We introduce a different perspective describing electron-phonon interactions in graphene based on curved space hydrodynamics. Interactions of phonons with charge carriers increase the electrical resistivity of the material. Our approach captures the lattice vibrations as curvature changes in the space through which electrons move following hydrodynamic equations. In this picture, inertial corrections to the electronic flow arise naturally effectively producing electron-phonon interactions. The strength of the interaction is controlled by a coupling constant, which is temperature independent. We apply this model to graphene and recover satisfactorily the linear scaling law for the resistivity that is expected at high temperatures. Our findings open up a new perspective of treating electron-phonon interactions in graphene, and also in other materials where electrons can be described by the Fermi liquid theory. For most solids, the temperature behaviour of the electrical resistivity changes at the Debye temperature, which corresponds to the theoretical highest phonon frequency in the material. In graphene, the Debye temperature is very high, 2. However, for low electron densities, the Fermi energy can be substantially smaller than the Debye energy, and only phonons with energy smaller than two times the Fermi energy, corresponding to a full backscattering of electrons, can scatter with the electrons. This defines the Bloch-Grüneisen temperature TBG3, which for doped suspended graphene is around 100 K5. Therefore, in suspended graphene, the behaviour of the resistivity changes at Bloch-Grüneisen temperature 7At finite temperatures, phonons interact with charge carriers, and therefore, contribute to the electrical resistivity of the respective material16. Hydrodynamics is an effective theory that describes the relaxation of any interacting system to thermal equilibrium, where the disorder only varies on long wavelengths compared to the electron-electron scattering length18. Several different models are used to account for the electron-phonon interaction in the hydrodynamic picture. Usually, in this hydrodynamic formalism, electron-phonon interactions are included into the equation for the electrical current density τp16. More elaborate theories model the presence of internal strain on a crystal lattice as an effective distortion to the induced metric20. Here, we present an approach based on the induced metric, where we account for the electron-phonon interactions by including inertial corrections due to the deformations of the graphene sheet. The novelty in our approach relies on the coupling of the hydrodynamics electron fluid with the atomistic simulation of graphene sheets. The deformations used in our model are directly derived from atomistic simulations. The graphene sheet in this atomistic simulation behaves as a two-dimensional manifold that changes in time due to thermal fluctuations. The electrons flow through this manifold when an external electric field is applied. In order to describe the electrons with hydrodynamic equations, we use a covariant representation where the existence of deformations translates into the appearance of inertial corrections. In this work, we considered doped graphene samples, i.e. we are away from the charge neutrality point, where charge carriers are induced by a gate voltage instead of thermal fluctuations, and therefore the Fermi liquid theory applies21.Recently it has been shown that the electronic flow in graphene can be modelled using hydrodynamic equations23. However, in this work, we use an approach in which the thermal fluctuations are responsible for inducing curvature in the graphene sheets. This curvature generates dissipation24 and electrical resistivity in the sample. The resulting inertial terms are added naturally to the electronic fluid equations depending on the complexity of the locally induced curvature. To the best of our knowledge, this approach has never been proposed before. With our model at hand, we address the question whether the curvature induced inertial corrections can recover the temperature relation of the electrical resistivity in the high temperature regime.Other models have been used to describe electron-phonon interactions as inertial forcesWe use molecular dynamics simulations to simulate different graphene membranes at different temperatures and imposed strains. From the position of the atoms, we build the coordinate system in which the electrons flow, and extract the inertial corrections to include them into the two-dimensional hydrodynamic equations. In Fig. 25. This many-body potential has been developed to simulate molecules made of carbon and hydrogen atoms, and has been very successful to reproduce the phonon dispersion curves of graphene26. In our simulations we consider suspended graphene sheets of Lx = 99.2 Å,  and accordingly the armchair edge along the y-direction (left and right). The atoms can freely move in all directions, except the ones at the left and right boundary, representing the electrical contacts  with a time step Δt = 1 fs, which is small enough to capture the dynamics of the carbon-carbon interactions accurately. Randomised velocities are attributed to the atoms at the beginning of each simulation. After reaching thermal equilibrium we are ready to couple the graphene sheet to the fluid solver and introduce electrical currents.To simulate the graphene sheets with molecular dynamics we use the adaptive intermolecular reactive bond-order (AIREBO) potentialNμ and T0 are the 3-particle flow and the energy-momentum tensor, respectively. The energy momentum tensor in Minkowski-space T0 depends on the Minkowski metric ημν and the shear-stress tensor πμν, which contains the shear viscosity κ. The equation of state completes this set of equations, which for the case of graphene is given by ε = 2p, where ε is the energy density and p the pressure. To take into account the curvature of suspended graphene sheets, we consider inertial corrections in these equations. For this purpose, we first use the covariant formulation of the hydrodynamic equations in curved space to determine the terms responsible for the inertial corrections, and afterwards, we introduce them as a forcing term into the respective equations for flat graphene. The conservation equations in curved manifolds are derived by replacing partial derivatives ∂μ by covariant derivatives ▽μ and considering the energy-momentum tensor in curved space Tμν, which depends on the generalised metric gμν instead of the Minkowski (flat) metric ημν. The covariant derivative ▽μ in the curvilinear coordinate system can be expressed through the respective partial derivative by 27.The electronic flow in flat graphene can be modelled using hydrodynamic equations, which are responsible for the conservation of particles, α in front of the inertial corrections which accounts for the strength of the electron-phonon interaction. Thus, the set of equations can be written asAt this stage we include a temperature independent coupling constant 28, and add the inertial contributions as external forces . Our model discretises space as regular triangular lattice, which we couple to graphene’s hexagonal lattice. As shown in Fig. To solve these equations, we make use of the lattice Boltzmann solver described in refsThe graphene sheet possesses zigzag boundaries at the left and right end. For the fluid solver we impose periodic boundary conditions at these boundaries, which correspond to the in- and outlet. The free sides of the graphene sheet possesses armchair geometry and, therefore, we impose free slip boundary conditions.n = 1.36 × 1013 /cm 2 and compare our results with the experimental set-up proposed by Efetov et al.4. We impose a constant particle density by coupling the fluid solver to a particle (charge) reservoir, thus fulfilling overall particle number conservation even for α ≠ 1. Therefore, at every time step during our simulations, we compensate the loss/gain of particles by injecting/subtracting charge carriers, such that the total number of particles is always conserved. This fulfills the role of the gate voltage to fix the Fermi level and therefore, the total number of carriers. To produce an electrical current, we apply an external electric field in x direction, Ex = 1.43 × 109 − 1011 V/m. In our simulations, we also set the chemical potential 2/s22. We use the shear viscosity for doped graphene given by10x0 = ΔxMD = 1 Å and time scale t0 = ΔtMD = 10−5 fs. After each iteration we compute the metric tensor and the Christoffel symbols and simulate the electronic flow until we obtain the electrical current at steady state. Note that since the electronic flow is much faster than the typical velocity of the carbon atoms, the electrons will reach stationary solutions under adiabatic approximations. However, we still couple both time and space variations on an equal footing. The momentum change in the fluid is imposed on the atoms to ensure momentum conservation of the total system even for We perform simulations in the Fermi liquid regime, in which the Fermi energy fixes the total number of charge carriers, and can determine whether electrons or holes dominate the charge carriers and electrical currents. Therefore, we set a constant particle density 13. Therefore, we can use it to simulate the electronic flow in doped graphene samples  within the Fermi liquid theory.Our numerical solver can reproduce both the non-relativistic and relativistic regimes of the hydrodynamics equations, as has been shown in refWe perform simulations for different strains and different values of the coupling constant and measure the resistivity of the graphene sheets using Ohm’s law, 5. Additionally, the slope γs(α) only depends on the strength of the coupling constant α but not on the applied strain, which is also in agreement with previous works7. We can also observe from the inset of Fig. γs∝α2.15 ± 0.03. The factor γs can be compared with the values from the Boltzmann transport theory5, whereρm = 7.6×10−7 kg/m2 being the mass density of graphene, vph the phonon velocity and D the deformation-potential coupling constant. Experimental and theoretical results suggest that the deformation-potential varies within the range of 6, and phonon velocities within 31. Thus, one expects γ to be in the range γ. The residual resistivity ρ0 is 704 ± 33 Ω for α = 0.1 and is a consequence of the static corrugations (ripples) present at any temperature. These ripples stabilize the two-dimensional crystal circumventing the Mermin Wagner theorem, which states that crystalline order cannot exist in two dimensions32.This linear dependence is in agreement with experimental measurements and theoretical predictions7, the data suggest a quadratic dependence of the resistivity on the temperature .The linear temperature dependence observed in this set-up is related to the presence of external strain imposed by fixing the contact points at the boundary. For the study of the strain free resistivity, we have performed molecular dynamics simulations of graphene sheets without restricting the motion of the carbon atoms at the left and right boundary. We have observed that in this case, the linear behaviour of the resistivity is not recovered. Instead, in agreement with refs24. The Ricci scalar  is a measure for the curvature and is given by The existence of a resistivity points to the presence of dissipation. Recently, it has been shown that energy dissipation in flows through curved manifolds arises from the curvatureWe have also studied the standard deviation of the heights of our graphene sheets (which represents out-of-plane vibrations), and found that they are virtually not influenced by temperature, within the range of 100–600 K . However, we observe that temperature does affect the bond-length distribution, as seen in Fig. 3a–c in the Supplementary Information, meaning that it influences the in-plane vibrations of the membranes. Thus, one can conclude that the linear dependence of the resistivity with temperature is mainly due to in-plane phonons, and may be related to the lack of out-of-plane vibrations, which are suppressed when an external strain is applied . This also explains why in the absence of strain, i.e. without the suppression of out-of-plane vibrations, the quadratic behaviour is recovered.α, and for values of γ known from theoretical predictions and experimental measurements. Our measured resistivity does not depend on the strength of the strain applied to the sample, however, in the complete absence of external strain it exhibits the expected quadratic temperature dependence7.To summarise, we have shown that inertial corrections lead to a linear dependence of the electrical resistivity with temperature in suspended graphene under applied strain, which is in agreement with experimental measurements of the electrical resistivity due to electron-phonon interactions at high temperatures. To characterize the strength of the electron-phonon interaction in our model, we have introduced a coupling constant We also analysed the maximal absolute value of the curvature as function of temperature and found a power-law behaviour with an exponent that changes slightly with the applied strain. Finally, by studying the average height fluctuations of the graphene sheets under strain, we also discovered that the height fluctuations are almost temperature independent, and consequently, they seem to be uncorrelated with the changes in curvature. In contrary, the bond-length distribution (which is related to the in-plane phonons) possesses a clear temperature dependence and accounts for larger local values of curvature when increasing the temperature. In our model, larger curvature implies more energy dissipation, and consequently, larger electrical resistivity.30.Our finding opens up many interesting questions, as for instance, if one can discern the influence of different types of vibrational phonons, e.g. flexural, acoustic, and optical, by studying how they introduce curvature into the hydrodynamic system. By extending our molecular dynamics simulations, one could also explore the electrical resistivity due to the electron-phonon interactions when the graphene sample is placed on a substrateIn our work, the adiabatic motion of the electronic flow (weak MD-hydro coupling) relies mainly on two facts: i) our approach is classical, and ii) the electronic flow moves much faster than the carbon atoms. Therefore, the electrical current reaches convergence very fast and one does not need to take into account the simultaneous motion of the graphene structure. This leads us to conclude that within a classical picture of the electron-phonon interaction in graphene, one can consider the spatial static curvature of the sample to explain the resistivity vs. temperature curves found experimentally in graphene. However, other features of this interaction coming from quantum effects are obviously not covered.Finally, our approach can also be applied to other two- and three-dimensional crystals, where electrons are well described as Fermi liquid. In those structures, ion displacements due to phonons can induce intrinsic curvature, and consequently, energy dissipation in the electronic flow. Applying our model to other materials will be an interesting subject for future research.Supplementary Material


The porous structure could act as an electrode directly, free of binder and conductive agent, which promotes an improved electron transfer, and provides a 3D network for an enhanced ion transport, thus leading to an increased capacity and stable long cycle stability performance. Notably, the specific capacity of MoS2/reduced graphene aerogel is 1041 mA h g−1 at 100 mA g−1. Moreover, reversible capacities of 667 mA h g−1 with 58.6% capacity retention are kept after 100 cycles. The outstanding performance is beneficial from the synergistic effect of the MoS2 nanostructure and graphene conductive network, as well as the binder-free design. These results provide a route to integrate transition-metal-dichalcogenides with graphene to fabricate composites with rich micro-pores and a three-dimensional network for energy storage devices.Hybrid MoSThe online version of this article (10.1186/s11671-019-2916-z) contains supplementary material, which is available to authorized users. Nowadays, the rapid development of electric vehicles and flexible electronics opens up an opportunity for the development of energy storage devices in the industrial and research communities , 2. Amon2) shows great advantages as the anode of LIBs due to its unique layered structure and high capacity (ca. 670 mAh g−1). However, its structure is prone to deteriorate during the charge/discharge process due to volume change, leading to a poor cycling stability. Numerous attempts have been conducted to enhance kinetic behaviors of MoS2 as LIBs anode. One method is to synthesis nano-size structure, in order to shorten the diffusion distance of lithium ions [2 and it proves to be in effect. Especially, graphene has drawn much attention benefiting from its outstanding conductivity and high surface area. Recently, graphene has been widely researched in many areas, such as conductive switching [2 nanosheets on graphene sheets, and a capacity of 1077 mAh g−1 at 100 mA g−1 after 150 cycles was obtained [2 and graphene [−1 was obtained. How to incorporate graphene with MoS2 to obtain the high-capacity and stable anode material is still an ongoing task [Recently, many researches have focused on high-performance anode materials for LIBs. 2D transition metal dichalcogenides (TMDs), with outstanding electrochemical performance, have won much attention and showed great potential as anode materials for LIBs , 7. Compium ions , 10. Anoium ions –13. Diffium ions –20, inclium ions  and grapium ions , 20, arewitching , photoluwitching , chemicawitching , and gaswitching  as well witching . For insobtained . Liu et graphene , and theing task .2/reduced graphene (MoS2/RGO) aerogel. With a solvothermal and freezing-drying process, the MoS2/RGO aerogel is fabricated and directly acts as the binder-free anode. Such a structure endows the MoS2/graphene aerogel with several advantages as an anode material. First, the graphene acts as a matrix to support the MoS2 nanostructures, which is beneficial to preventing graphene sheets from restacking. Second, the hierarchical nanostructure provides a good adhesion between graphene and MoS2, which ensure a stable structure and thus guarantee a long cycling stability. Third, the graphene with high conductivity promotes an improved electron transfer and acts as a basis to alleviate volume expansion of MoS2 in the charge/discharge process. Fourth, such a binder-free design shortens the ion diffusion distance, leading to an enhanced ion transport. The reversible capacity of the as-prepared binder-free MoS2/RGO aerogel is up to 667 mA h g−1 at 100 mA g−1 after 100 cycles. This method provides a route to fabricate the high-performance lithium-ion anode material.Herein, a facile and low-cost approach is used to prepare a hierarchical nanostructure of MoS2/RGO aerogels were prepared with a one-step hydrothermal method. In detail, 60 mg of (NH4)2MoS4 were dissolved in 10 mL of N, N-dimethylformamide (DMF) solvent. Five milliliters of GO aqueous (5 mg mL−1) were added, and a homogeneous solution was obtained under sonication for several hours. The solution was put to a Teflon-lined autoclave and sealed. Finally, it was heated in the oven at 200°C for 12 h. MoS2/RGO hydrogels were obtained through washing with ethanol and D.I. water. Through freeze-drying and annealing in 700°C for 2 h, the final MoS2/RGO aerogels were obtained. As a comparison, the MoS2 powder was prepared with the same steps except adding GO.All reagents were of analytical grade. A modified Hummers’ method was used to prepare graphene oxide (GO) for further use . The MoS2/RGO film which was cut from the MoS2/RGO aerogels was used to carry out further characterization. Field mission scanning electron microscopy  and field-emission transmission electron microscopy  were used to characterize the obtained samples. XRD analysis  with Cu Kα radiation (λ = 1.5406 Å) from 10° to 80° was used to confirm the substance of the MoS2/RGO film and MoS2 powder.A thin piece of MoSThe MoS2/RGO film was directly used as a binder-free anode, without any binder and conductive agent. It was assembled into a coin-type half-cell in a glove box, with a lithium foil acting as counter electrode and Celgard 2400 polymer as separator. The electrolyte consisted of 1 M LiPF6 in ethylene carbonate (EC) and diethyl carbonate (DEC). After assembly, the cell was aged 24 h in the glove box for further measurements. The galvanostatic charge/discharge (GCD) measurements were carried out with a battery measurement system , and cyclic voltammetry (CV) testings were conducted with Autolab workstation (PGSTAT-302N). The testing was conducted in the potential range of 0.01–3.0 V (vs Li1/Li). Electrochemical impedance spectra (EIS) experiments were carried out with 10 mV amplitude in the frequency from 100 kHz to 0.01 Hz.2/RGO aerogel could keep integrate structure. The excellent mechanical behavior was beneficial from the rich porosity of the whole structure and the interconnection of graphene layers, showing great potential as a binder-free electrode.The MoS2/RGO aerogels were fabricated with a hydrothermal method, freeze-drying and heat treatment. Figure 2/rGO aerogel. A porous structure with wrinkled graphene layers interconnected with each other was observed  and (100) planes of MoS2 [2 planes [Figure  of MoS2 . The SAE2 planes . These r2 powder could be responsible for hexagonal 2H–MoS2 (JCPDS 37-1492). The strong reflection peak at 2θ = 14.2o belonged to the (002) plane, with a d-spacing of 0.62 nm. MoS2/RGO composite showed the similar crystalline structure of pure MoS2, indicating a layered structure. Comparing with the MoS2 samples, an obvious peak in 26.3° was observed in the MoS2/RGO samples, which could be the (002) diffraction peak of graphene, revealing the graphene substance in the composites [2, which was consistent with the previous SAED pattern results. Notably, the MoS2 (002) reflection peak, which indicated a stacked nature of layered MoS2, was weakened for the MoS2/RGO composite, suggesting the formation of a few-layer MoS2 structure [2, further confirming that the MoS2 was wrapped by graphene layer in the MoS2/RGO aerogels [X-ray diffraction (XRD) experiments were also carried out. As shown in Fig. mposites . It was tructure . The peaaerogels .Fig. 3a 2 nanostructure and graphene layer, Raman spectroscopy measurements were also carried out [2/RGO aerogel showed the E2g and A1g peaks of MoS2 at the frequencies of 380.2 and 403.6 cm−1 [2 nanostructure with different fabrication method would display an A1g peak at 402–404 cm−1 [2 crystals in the MoS2/RGO aerogel. Besides, the peaks at 1354.3 cm−1 and 1591.6 cm−1 were observed in Fig. ID/IG was usually associated with the graphene defects [To further confirm the nature of MoSried out –35. As s3.6 cm−1 , 36. Not404 cm−1 –39, furt defects .−1 were carried out. Figure 2/RGO electrode. The peak at 0.95 V was related with Li+ intercalation into MoS2 interlayer space to form LixMoS2, with a phase transformation process to become 1T structure of LixMoS2 from 2H  [2S and metallic Mo from LixMoS2 [2/RGO electrode in the reverse anodic scans, indicating the formation of sulfur [2 were formed after the first cycle and they were kept the same in subsequent cycles [2/RGO composite. The first three GCD curves of the MoS2/RGO and MoS2 electrodes were shown in Fig. 2, and the plateau at 0.65 V was related with the reaction of forming Mo particles from MoS2. A slope potential curve was observed below 0.52 V in the first discharge cycles, meaning the appearance of gel-like polymeric layer due to the degradation of electrolyte [2 electrode showed plateaus at 2.0, 1.20 and 0.45 V in the following discharge curves. In the charge process, an obvious plateau at 2.35 V was observed for the MoS2 electrode. For the MoS2/RGO electrode  , 44. The LixMoS2 –47. In tf sulfur . It coult cycles , 48–50. ctrolyte –53. The sibility , 56.Fig.2/RGO electrode and MoS2 electrodes were shown in Fig. 2 electrodes, MoS2/RGO electrodes delivered higher capacities. A capacity of 1041 mAh g−1 at 100 mA g−1 was kept after 50 discharge/charge cycles for the MoS2/RGO electrode, indicating a good electrochemical reversibility as well as a long cycle stability. By comparison, the MoS2 electrode only kept 512 mAh g−1 capacity at 100 mA g−1 after 50 cycles. Moreover, the specific capacity of the MoS2 electrode decreased a lot when the current decreased from 2000 mA g−1 to100 mA g−1. The cycling results conducted at 100 mA g−1 were shown in Fig. 2 electrode showed a poor cycling performance. There was nearly no decrease in its initial 20 cycles. However, the reversible (charge) capacity decreased from 892 mAh g−1 to 110 mAh g−1 after 100 cycles, with only 12.3% capacity retention. On the contrary, the MoS2/RGO electrodes displayed an improved cyclic stability. A reversible capacity of 667 mAh g−1, with a 58.6% capacity retention was obtained after 100 cycles. The rate performances and cycling stability of pure RGO electrode were also displayed in Additional file −1 at 100 mA g−1. When the current density reversed from 2000 mA g−1 to100 mA g−1, the specific capacity of 202.2 mAh g−1 was kept for the RGO electrode. Table 2 nanostructure, which was beneficial to preventing aggregation of MoS2. Secondly, the graphene with good conductivity reduced transfer resistance and promoted electron transmission and ion transport, leading to an improved rate capability. Thirdly, the RGO aerogel with multi-scale porous structure acted as an elastic buffer layer, which effectively restrained the volume expansion during the delithium-lithium process, and thus lead a better cycling stability.The rate performances of MoS2/RGO and MoS2 electrodes after 100 discharge-charge cycles at 100 mA g−1. The first semicircle represented lithium ion migration resistance through the SEI films (R1), while the second semicircle stood for the resistance of charge transport (Rct). R2 was related with the resistance of electrolyte [2/RGO and MoS2 electrodes. The fitted values were listed in the Fig. 2/RGO electrode (10.74Ω) was smaller than MoS2 (44.07 Ω), indicating that rGO could bring an improved charge transfer process during discharge-charge actions and thus show a good rate capability.Electrochemical impedance spectra (EIS) measurements were also conducted for the samples. Figure ctrolyte . ZView s−1 Additional file 2:Figure S2. Mechanical performance of the MoS2/RGO aerogel before compression (a), under compression (b), and after compression (c). (PNG 2203 kb)Additional file 3:Figure S3. (a) TEM picture of the MoS2/RGO sample. (b) TEM-EDS mapping of Mo, S, C elements. (c) EDX spectra of the MoS2/RGO sample. (JPG 304 kb)Additional file 4:Figure S4. (a) Rate performances of RGO aerogel electrodes at different current densities. (b) Cycling performance of RGO electrodes at a constant current density of 100 mA g−1. (JPG 114 kb)Additional file 5:Figure S5. FESEM images of  MoS2/RGO electrode,  cross-sectional images of MoS2/RGO and SEM images of  bare MoS2 electrode after 100 cycles performed with a current density of 100 mA g−1. (JPG 1649 kb)


Inhibition of PD-L1 signalling by using PD-L1/−− mice or by blockage of PD-L1 in wildtype mice resulted in an increased Treg frequency in the inflamed kidney. However, mice lacking PD-L1 developed more severe NTN associated with an elevated pathogenic renal Th1 immune response, which was reversed by blockage of IFNγ in these mice. Interestingly, lack of PD-L1 altered the gene expression profile of Tregs in homeostasis and kidney inflammation. Functionally, Tregs from nephritic PD-L1/−− mice had impaired suppressive capacity in vitro and failed to protect from NTN in vivo. Thus, PD-L1 displays a protective role in NTN, which is related to Treg-mediated suppression of the Th1 immune response.Immune-mediated glomerular diseases like crescentic glomerulonephritis (cGN) are driven by inappropriately regulated cellular and humoral immune responses subsequently leading to renal tissue injury. Recent studies demonstrated the crucial role for regulatory T cells (Tregs) in suppressing pathogenic T-cell responses during nephrotoxic nephritis (NTN), a murine model of cGN. However, mechanisms of immune regulation in cGN are less clear. Here, we aim at investigating the role of the co-inhibitory PD-1/PD-L1 pathway in Treg-mediated suppression of renal inflammation. We demonstrated that Foxp3 The PD-l/PD-L1 pathway exerts important functions in immune regulation and promotes development and function of regulatory T cells (Tregs) by induction and maintenance of the Treg-specific transcription factor forkhead box protein P3 (Foxp3)3. Binding of PD-L1 to PD-1 during primary T-cell activation induces blockage of T-cell proliferation and cytokine production and inhibits cytotoxic activity and cell survival5. Moreover, effector T-cell reactivation and function is also negatively regulated by the PD-1/PD-L1 interaction7.Crescentic glomerulonephritis (cGN) is a severe glomerular disease characterized by formation of glomerular crescents in Bowman’s space and a rapid loss of renal function. Inappropriately regulated cellular and humoral immune responses, which may result from defects in central and peripheral tolerance, drive cGN. Negative co-stimulatory pathways are crucial for the maintenance of peripheral tolerance by inducing inhibitory signals in lymphocytes. One negative co-stimulator receptor expressed on activated T cells and B cells is programed cell death-1 (PD-1) that is bound by programed cell death ligand-1 (PD-L1) and PD-L2. PD-L1 is expressed by hematopoietic and non-hematopoietic cells and can be further induced during inflammation. In contrast, PD-L2 expression is mostly restricted to activated dendritic cells (DCs) and macrophages8. Moreover, aged PD-1/−− mice were shown to develop lupus-like glomerulonephritis9. Renal expression of PD-L1 was demonstrated in patients with lupus nephritis, tubulointerstitial nephritis or renal cell carcinoma10. Furthermore, several studies revealed that blockage of PD-1/PD-L1 interaction aggravated murine accelerated nephrotoxic serum nephritis11, ischemia reperfusion-induced kidney injury12, adriamycin nephropathy13 or lupus-like nephritis14. However, mechanisms by which the PD-1/PD-L1 pathway mediates immunosuppression during kidney disease are less clear.The PD-1/PD-L1 pathway has been implicated in immune regulation of kidney diseases. A single nucleotide polymorphisms in the PD-1 gene was associated with increased susceptibility of patients to systemic lupus erythematosus19. CD4+ Foxp3+ Tregs are crucial for the control of such pro-inflammatory immune responses to prevent excessive tissue damage and autoimmunity. We have shown recently that Tregs contribute to immune regulation in nephrotoxic nephritis (NTN), the murine model of cGN, by inhibiting the pro-inflammatory Th1 immune response thereby ameliorating disease pathogenesis20. The suppressive effect of Tregs during NTN was partially attributed to expression of the anti-inflammatory cytokine IL-1021. In the present study, we investigated the immunoregulatory role of the co-inhibitory PD-1/PD-L1 pathway in Treg-mediated protection from renal injury.Kidney-infiltrating Th1 and Th17 cells were found to drive renal inflammation in murine models of cGN by production of the pro-inflammatory cytokines interferon-γ (IFNγ) and IL-17, respectivelyPD-L1/−− mice develop aggravated NTN and that lack of PD-L1 expression by cells of hematopoietic origin worsened disease pathogenesis11. Based on these finding, we asked whether Tregs might be responsible for PD-L1-mediated protection in NTN. Therefore, we induced NTN by injection of the nephritogenic NTN serum in FIR-tiger mice, which allow distinct detection of the Treg-specific transcription factor Foxp3 via flow cytometry22, and did Treg analysis in the T cell-mediated autologous phase 8 days after NTN induction. We analyzed glomerular damage by quantification of crescent formation in periodic acid-Schiff (PAS)-stained kidney sections20 and determination of proteinuria in urine by measurement of the albumin-creatinine-ratio. NTN serum-treated FIR-tiger mice developed severe NTN characterized by a high percentage of crescent formation and proteinuria whereas in naive FIR-tiger mice neither crescents nor proteinuria were detectable  mice. Moreover, we found no substantial difference in the frequencies of CD44lo CD62L+ central Tregs or CD44hi CD62L− effector Tregs  mRNA, which was absent in FIR-tiger-PD-L1/−− mice. We showed mRNA expression of PD-L2 (Pdcd1lg2) during NTN that was not altered in mice lacking PD-L1. In contrast, renal PD-1 (Pdcd1) mRNA expression was up-regulated in nephritic FIR-tiger-PD-L1/−− mice compared to nephritic FIR-tiger mice  and IL-12p40 (Il12b), and of the transcription factor T-bet (Tbx21) compared to nephritic WT mice. This correlated with enhanced expression of the IFNγ-inducible, Th1 cell-recruiting chemokine CXCL10 (Cxcl10) in nephritic PD-L1/−− mice. In contrast, mRNA expression of genes associated with a Th17 cell-mediated immune response such as IL-6 (Il6) and RORγt (Rorc) was down-regulated  during renal inflammation whereas Tregs from nephritic FIR-tiger-PD-L1/−− mice showed decreased expression. We demonstrated increased expression of molecules associated with Treg function such as CD39 (Entpd1) and T-cell immunoreceptor with Ig and ITIM domains (Tigit) in the absence of PD-L1. In contrast, only Tregs from FIR-tiger mice showed enhanced expression of granzyme B (GzmB) during NTN. Lack of PD-L1 resulted in up-regulated expression of the chemokines CXCL10, CCL5, and XCL1, of the cytokine colony stimulating factor 1 (CSF1), and of the chemokine receptor CXCR3 34, and worsened disease pathogenesis of accelerated NTN11. We confirmed the pathological findings of the study by Menke et al. by using FIR-tiger-PD-L1/−− and PD-L1/−− mice and by blockage of PD-L1 in WT mice. The authors also showed that PD-L2/−− mice developed more severe accelerated NTN indicating an immunoregulatory function for the second PD-1 ligand in kidney inflammation11. However, renal expression of PD-L2 was not altered in nephritic FIR-tiger-PD-L1/−− and PD-L1/−− mice and despite up-regulated expression of PD-1, PD-L2 did not compensate the absence of PD-L1.The immunosuppressive function of the PD-1/PD-L1 pathway was demonstrated in several autoimmune diseases. 39. Systemic activation of the PD-1/PD-L1 pathway by injection of a PD-L1/Fc fusion protein ameliorated progression of intracerebral hemorrhage40, colitis41, and collagen-induced arthritis42. In kidney disease, administration of a recombinant adenovirus encoding PD-L1 attenuated lupus-like nephritis43, and treatment with a PD-L1/Fc fusion protein ameliorated experimental autoimmune glomerulonephritis in rats44. In contrast, inhibition of the PD-1/PD-L1 pathway by administration of the checkpoint inhibitors pembrolizumab or nivolumab during cancer immunotherapy caused a higher incidence of acute interstitial nephritis in patients with melanoma or lung cancer45. The results of our study illustrate the important immunoregulatory function of the PD-1/PD-L1 pathway in NTN by ensuring proper Treg function in renal inflammation. Therefore, stimulating this pathway may provide a therapeutic option in cGN.Several therapeutic strategies activating the PD-1/PD-L1 pathway in autoimmune disease have been tested in mice. One study reported that overexpression of PD-L1 on DCs reduced severity of EAEPD-L1/−−, Rag1/−−, CD45.1, FIR-tiger (Foxp3-IRES-mRFP [FIR] x IL-10-IRES-GFP [tiger])22, and FIR-tiger-PD-L1/−− mice were bred in the animal facility of the University Medical Center Hamburg-Eppendorf . A detailed genotyping protocol of FIR-tiger-PD-L1/−− mice and analysis of PD-L1 expression in these mice is shown in Supplemental Figs PD-L1/−− mice were provided by Richard Flavell  and Lieping Chen , respectively. Mouse experiments were conducted according to the German animal protection law and approved by the institutional review board . Mice received humane care according to the national guidelines of the National Institutes of Health in Germany.C57BL/6, 46. Mice were sacrificed 8 days after NTN induction. To assess systemic antibody response, heart blood was drawn from individual mice. One day before killing, mice were housed in metabolic cages for urine collection. Albuminuria was determined by ELISA . C57BL/6 mice were treated i.p. with an anti-PD-L1 antibody  daily starting one day after NTN induction. As isotype control, mice received rat IgG2b . PD-L1/−− mice received i.p. an anti-IFNγ antibody  one day before and 4 days after NTN induction. As isotype control, rat IgG1  was injected.NTN was induced in male mice (8–12 weeks old) by intraperitoneal (i.p.) injection of 2.5 mg nephrotoxic sheep serum per gram of mouse body weight as described previously47. Crescent formation was assessed in 30 glomeruli/mouse in a blinded fashion in PAS-stained, paraffin-embedded kidney sections.Immunohistochemistry was performed by routine procedures as described previouslyMouse anti-sheep IgG antibody titers were measured by ELISA using sera collected 8 days after NTN induction. In brief, ELISA microtiter plates were coated with 100 µl sheep IgG  in carbonate-bicarbonate buffer overnight at 4 °C. After blocking with 1% BSA in TBS, the plates were incubated with serial dilutions of mouse serum for one hour at room temperature. Bound mouse IgG was detected using peroxidase-conjugated goat anti-mouse IgG , TMB peroxidase substrate , and absorbance readings (at 450 nm). Lack of cross-reactivity of the secondary antibody with sheep IgG was demonstrated by omitting the primary antibody. Bound mouse immunoglobulin isotypes were detected using peroxidase-conjugated rabbit anti-mouse IgG , IgG1, IgG2a/c, and IgG2b antibodies .4Cl. Kidneys were finely minced and digested for 40 min at 37 °C with 0.4 mg/ml collagenase D  and 0.01 mg/ml DNase I (Roche) in RPMI 1640 supplemented with 10% heat-inactivated fetal calf serum (Thermo Fisher Scientific). Erythrocytes were lysed with NH4Cl and cell suspensions were sequentially filtered through 70 µm and 40 µm nylon meshes and washed with Ca2+- and Mg2+-free HBSS (Thermo Fisher Scientific).Kidneys and spleens were harvested from nephritic mice 8 days after NTN induction. Splenic tissue was passed through 70 µm nylon meshes prior to erythrocyte lysis using NHRenal cells and splenocytes were incubated with anti-CD16/32 antibody  prior to antibody staining to prevent unspecific binding. LIVE/DEAD Fixable Red Dead Cell Stain Kit (Thermo Fisher Scientific) was used to exclude dead cells. Cells were surfaced-stained with fluorochrome-labeled antibodies specific to CD3 , PD-1 , PD-L1 , CD4 , CD45.1 , CD45 , CD11b , CD11c , Ly-6C , MHCII , TCRβ , CD25 , Nrp-1 , Helios , CD44 , CD62L . For intracellular cytokine staining, cells were stimulated with phorbol myristate acetate (10 ng/ml) and ionomycin (250 ng/ml) for 5 h with the addition of brefeldin A  after 30 min. After surface and Live/Dead staining, cells were fixed in Fix/Perm solution before incubation in Perm/Wash buffer (both BD Biosciences) with antibodies specific to IFNγ  and IL-17A . For intranuclear staining, cells were fixed using the Transcription Factor Staining Buffer Set (eBioscience) and incubated in Permeabilization buffer with an antibody specific to Foxp3 . Flow cytometry data were analyzed by using fluorescence minus one controls.6 cell/ml in RPMI 1640 medium supplemented with 10% fetal bovine serum, 1% penicillin/streptomycin, 1% sodium pyruvate, and 0.1% β-mercaptoethanol  in the presence of 20 µg/ml sheep IgG for three days. Cytokine levels were determined in culture supernatants using 96-well high-binding flat-bottom microtiter plates  and Duo Set ELISA for IFNγ  according to the manufacturer’s protocol.Splenocytes were cultured at a density of 4 × 10PD-L1/−− and WT mice 8 days after induction of NTN. Therefore, CD4+ T cells were enriched using the CD4+ T Cell Isolation Kit . Subsequently, CD4+ CD25hi Tregs were sorted by FACS . CD4+ CD25− responder T cells from CD45.1 mice were isolated by FACS and labeled with Cell Proliferation Dye eFlour670. Then, 1 × 105 responder T cells were co-cultured with 1 × 105 Tregs in the presence of an anti-CD3 antibody  for 3 days.Tregs were isolated from + CD25hi Tregs were sorted by FACS from nephritic PD-L1/−− and WT mice. 1 × 106 FACS-sorted CD4+ CD25− T cells from CD45.1 mice were adoptively transferred into Rag1/−− mice either alone or in combination with 5 × 105 Tregs from nephritic PD-L1/−− or WT mice. After 2 days, NTN was induced and mice were analyzed 8 days later.CD4Total RNA was isolated from shock-frozen kidney tissue using the NucleoSpin RNA Kit  according to the manufacturer’s instruction. RNA was transcribed into cDNA using the Verso cDNA Synthesis Kit  on a MyCycler thermal cycler . Quantitative RT-PCR was performed using the ABsolute qPCR SYBR Green Mix (Thermo Scientific). The relative mRNA levels were calculated using the ∆∆CT method after normalization to the reference genes β-actin or 18 S. Quantification was shown in x-fold changes to the corresponding control cDNA. Primers were obtained from Metabion . Sequences of the primers are listed in Supplemental Table + Tregs were isolated from spleen and lymph nodes of naive and nephritic FIR-tiger and FIR-tiger-PD-L1/−− mice. Therefore, CD4+ T cells were enriched from single cell suspensions by using the CD4+ T Cell Isolation Kit (Miltenyi Biotec). Thereafter, CD4+ Foxp3+ (mRFP+) Tregs were purely isolated by FACS. RNA of 1–2 × 106 Tregs was isolated by the RNeasy Mini Kit (Quiagen) and digested with RNase-free DNase I (Quiagen) according to the manufacturer’s instructions. Gene expression analysis was performed using the NanoString assay with the nCounter Immunology Panel profiling 561 immunology-related genes  according to the manufacturer’s instructions. The results were analyzed with the nSolver Analysis Software 2.5 (NanoString Technologies). Data were calculated in x-fold changes compared to the corresponding control mRNA and displayed as heat map using the web server Heatmapper48. Clustering was done using the average linkage and the Pearson distance.Foxp3Data were analyzed using the GraphPad Prism software . Statistical comparison was carried out using the Mann-Whitney U test or the one-way ANOVA with post analysis by Tukey-Kramer test. Data were expressed as means ± SEM. A p value of less than 0.05 was considered statistically significant with the following ranges *p < 0.05, **p < 0.01, and ***p < 0.001.Dataset 1


Moreover, the ability of GO to protect DNA and RNA from enzymatic digestion renders it one of the best candidates for biosensors based on these nucleic acids. This is an up-to-date review of the use of GO and RGO in sensors.Natural methylxanthines, caffeine, theophylline and theobromine, are widespread biologically active alkaloids in human nutrition, found mainly in beverages . Their detection is thus of extreme importance, and many studies are devoted to this topic. During the last decade, graphene oxide (GO) and reduced graphene oxide (RGO) gained popularity as constituents of sensors  for methylxanthines. The main advantages of GO and RGO with respect to graphene are the easiness and cheapness of synthesis, the notable higher solubility in polar solvents , and the higher reactivity towards these targets (mainly due to π–π interactions); one of the main disadvantages is the lower electrical conductivity, especially when using them in electrochemical sensors. Nonetheless, their use in sensors is becoming more and more common, with the obtainment of very good results in terms of selectivity and sensitivity (up to 5.4 × 10 Graphene oxide (GO) is a nanostructured material formed by graphite sheets (graphene) in which some of the aromatic C=C double bonds are oxidized, introducing oxygen atoms and giving rise to different functional groups . Due to the noteworthy importance of graphene and graphene oxide as nanomaterials in various application fields, a very high number of papers regarding their production can be found in the literature along with reviews ,2,3, to As effectively outlined by Jiang , the pecGO, among other nanostructured materials, has the advantage of being easily obtained by chemical oxidation of graphite; it has a two-dimensional structure , whose sOne of the important applications in which GO and its derivatives can give good results is the selective detection of important natural products, e.g., natural methylxanthines. These are natural compounds which can be found in many botanical species. The principal and most important examples of this category of molecules are theophylline, theobromine and caffeine . They caDue to the importance and diffusion of natural methylxanthines, their detection and quantification in solution  is the target of many studies and patents ,19,20.The design, development, realization, and optimization of GO and RGO-based devices require the analysis of their physical and chemical properties. The growing popularity of these nanomaterials stimulated the synergistic use of many different methods for this purpose ,22. ElecInformation about structural arrangements can be obtained by selected area electron diffraction (SAED) and reflection high-energy electron diffraction (RHEED) coupled with TEM and SEM . FinallyChemical structures of these materials can be analyzed through solid-state nuclear magnetic resonance (SSNMR) spectroscopy , while aThe scope of this minireview is an up-to-date focus on the use of GO and its derivative RGO as materials for the detection of natural methylxanthines, in biological and non-biological samples . As one of the applications of GO and RGO is biomedical, their possible toxicity should also be considered, which seems not to be negligible, as recently pointed out ,34,35,36It is important to underline that natural methylxanthines sequestration, detection and quantification are very significant topics in current research and the search for methods which allow for very low detection limits and selectivity is still ongoing. In this regard, electrochemical methods are usually more sensitive and selective than other methods  and thus the main applications of GO and RGO revised in this paper will be in electrochemical sensors.To obtain electrochemical sensors for complex matrices applications, in which the selectivity is the main topic, further modifications of GO and RGO composites are thus encouraged and can be considered possible routes for new research activities.The different application fields of GO and RGO will be reviewed in different paragraphs, starting from the use of these materials as simple adsorbents for xanthines, followed by their use in electrode surface modification in xanthines electrochemical sensors, and last in fluorescence sensors based on DNA and RNA. In all cases, the main advantage in using GO and RGO is their ability to chemically bind methylxanthines.Due to the near ubiquity of natural methylxanthines (mainly caffeine) in wastewaters and beverages, a good effort was made to find suitable adsorbent materials (often composites) for remediation . The mai−1 for caffeine was obtained (10 times higher than using GO instead of RGO). The interactions involved in this process are mainly electrostatic and π–π. Moodley and Akpotu [−1  is necessary, along with the possibility of reusing the material in subsequent runs without efficiency loss. As regards the adsorbents reported in In addition to the use of GO and RGO as materials for water remediation and xanthine adsorption, their use in natural methylxanthines determination and quantification in real samples is growing more and more. We will now refer only to the use of GO and RGO in adsorption followed by HPLC quantification, leaving their use in sensors to other paragraphs. The efficiency of these materials in the adsorption of methylxanthines from liquid phases, followed by complete (or nearly complete) desorption and quantification is demonstrated by the data reported in 3O4 nanoparticles were synthesized and used for caffeine extraction, followed by GC analysis. A noteworthy 0.1 ng mL−1 detection limit was obtained  as adsorbent, followed by HPLC analysis  of natural methylxanthines (mainly caffeine), their detection and quantification using a sensor is a very important task. A chemical sensor is a small device that is able to detect particular molecules and transform this detection into a signal . An elec−7 mol L−1), and it was successfully applied to original samples (beverages).Recently, GO has gained popularity as one of the compounds used for obtaining modified electrodes for electrochemical sensors , due to −6 mol L−1 , due to the noteworthy electrocatalytic activity of this modified electrode, and high long-term stability . In fact, a long lifetime and a good storage stability guarantee for a convenient use (and reuse) of a sensor, especially in case of expensive materials (in terms of preparation costs and times). In all reported cases, very good results were obtained in methylxanthines detection, under very diluted conditions, using GO as an electrode modifier in association with different materials, the most efficient (for both detection limit and detection range) being the composite formed by GO, SnS and TiOs of ten , entry 3−7 mol L−1 and a linear detection range of 8 × 10−7/6 × 10−5 mol L−1 . To decrease the extent of such an oxygenated functionalization, enhancing the electrical conductivity, still maintaining a good solubility in polar solvents (one of the major merits of GO), a chemical or electrochemical partial reduction of GO to yield reduced graphene oxide (RGO) and electrochemically reduced graphene oxide (ERGO) is possible . In the  mol L−1 , entry 1−7 mol L−1); the electrocatalytic effect was reported to be due to π–π interactions between caffeine backbone and ERGO structure 2 composite, which they used to modify a glassy carbon electrode for a caffeine electrochemical sensor , yielding a caffeine electrochemical sensor with a good detection limit of 2.6 × 10−7 mol L−1  in methylxanthines detection has many advantages over the use of GO, mainly related to the lower reactivity (lower oxygenation degree) of the reduced form. This is well documented by the higher number of examples of use of RGO in electrochemical sensors with respect to GO . AdditioDuring the last decade, the ability of graphene oxide to protect single-stranded DNA (ssDNA) and RNA (ssRNA) from enzymatic digestion has become evident. This effect is very important when ssDNA or ssRNA aptamers are used in fluorescence biosensors, as their enzymatic digestion would lead to an increase of fluorescence also in the absence of the target molecule, giving a false positive result . An apta−6 mol L−1  when the aptamer is bound to the target molecule. So a fluorescent aptamer bound to GO will result in a quenching of fluorescence, while when the aptamer is bound to the target will generate fluorescence again. It should be noted that all these are non-covalent bonds. Li and coworkers  were abl−7 mol L−1, −8 mol L−1  and linear detection range.The higher reactivity of GO with respect to that of RGO is thus very useful in DNA and RNA protection, giving rise to aptasensors with noteworthy performances in terms of both detection limit . Their biological activities  account for such a diffusion, both in pharmaceutical formulations and in food. It is thus clear the importance of their detection and quantification and, in some cases, sequestration. Specific chemical and electrochemical sensors and biosensors are the targets of many studies, with the aim of obtaining devices which are reliable, sensitive, selective, reusable, long-term stable, and cheap.Graphene derivatives are gaining popularity in this field. In particular, graphene oxide (GO) and reduced graphene oxide (RGO) are the first choice in the graphene family, due to the greater ease of obtaining them with respect to graphene and to the higher solubility in polar solvents . On the other hand, GO has a lower electrical conductivity than graphene, and a very high reactivity, due to the abundance of oxygenated functional groups. An increase in electrical conductivity and a decrease in reactivity, still maintaining the high stability and solubility, is obtained with the partial reduction of GO  to yield RGO or ERGO. These graphene derivatives are therefore the object of many studies to obtain optimal sensors for methylxanthines detection. The interactions between GO (or RGO or ERGO) and methylxanthines are mainly electrostatic and π–π. Moreover, the high surface area of these 2D graphene derivatives allows for a very high extent of interactions with the analytes, rendering GO and RGO  very good adsorbents for these natural products. In most cases, an efficient desorption and adsorbent regeneration and reuse was possible, without efficiency loss.The ability of GO and RGO to bind  methylxanthines can be exploited in electrochemical sensors, in which the electrode surfaces can be modified with these graphene derivatives. The effect of such a modification can be an enhancement of the current signal and/or an anticipation of the discharge potential .−10 mol L−1 for caffeine and 1.8 × 10−9 mol L−1 for theophylline) to be achieved, thanks to the ability of GO and RGO to “concentrate” these analytes on the electrode, mainly by π–π interactions.A quick look at the reference section of this minireview immediately reveals the relevance of such a topic. In fact, all the papers concerning the use of GO and RGO in methylxanthines detection date to the last decade, and their number is increasing. GO and RGO have been used in electrochemical sensors allowing very low detection limits  with respect to sensors of other kinds , this minireview also aims to be a stimulus for the search of new GO/RGO-based composites to enhance the performances, taking into account the noteworthy effect of GO and RGO on the electrochemical response of analytes, mainly due to the not covalent interactions between these graphene derivatives and methylxanthines.On the whole, it seems quite reasonable to predict a short/medium time to market for devices and systems using GO and RGO. In such a framework, a positive outlook can be envisaged for an effective and quick technology transfer of the use of GO and RGO for the methylxanthines adsorption and detection. This minireview proposes as a useful and up-to-date tool for those who want to work in this interesting research field.


TAR DNA binding protein (TDP-43) is a nucleic acid binding protein associated with insoluble cytoplasmic aggregates in several neurodegenerative disorders, including 97% of the ALS cases. In healthy individuals, TDP-43 is primarily localized to the nucleus; it can shuttle between the nucleus and the cytoplasm, and is involved in several aspects of RNA processing including transcription, splicing, RNA stability, transport, localization, stress granule (SG) formation, and translation. Upon stress, TDP-43 aggregates in the cytoplasm and associates with several types of RNA and protein assemblies, resulting in nuclear depletion of TDP-43. Under conditions of prolonged stress, cytoplasmic TDP-43 undergoes liquid-liquid phase separation (LLPS) and becomes less mobile. Evidence exists to support a scenario in which insoluble TDP-43 complexes sequester RNA and/or proteins causing disturbances in both ribostasis and proteostasis, which in turn contribute to neurodegeneration. However, the relationship between RNA binding and TDP-43 toxicity remains unclear. Recent studies provide conflicting views on the role of RNA in TDP-43 toxicity, with some finding RNA as a toxic factor whereby RNA binding contributes to TDP-43 toxicity, while others find RNA to be a protective factor that inhibits TDP-43 aggregation. Here we review and discuss these recent reports, which ultimately highlight the importance of understanding the heterogeneity of TDP-43 assemblies and collectively point to solubilizing TDP-43 as a potential therapeutic strategy. Although deficiencies in several dozen genes have been associated with ALS  and drives aggregation  or ALS exhibit ubiquitinated, tau-negative inclusions localized to the cytoplasm and containing TDP-43 that are distinct from amyloid deposits seen in other neurodegenerative disorders  highlight alterations in synaptic transmission, neurotransmitter release and endocytosis with several ligand- or neurotransmitter-gated ion-channels and neuropeptide receptors being misexpressed. Furthermore, loss of TBPH leads to altered splicing of transcripts including the voltage-gated calcium channel, cacophony. A subsequent study showed that null mutants for TBPH cause locomotor deficits and reduced amounts of cacophony protein at the neuromuscular junctions in Drosophila  as well as insoluble protein complexes. SGs are non-membrane bound organelles that assemble when translation initiation is inhibited or during stress  and toxic inclusions that disrupt nuclear transport . TDP-43 RNA granules were more spherical and more dynamic in distal end than in proximal axons. Additionally, RNP transport granules formed in ALS associated TDP-43 mutant models were more viscous and showed disrupted dynamics. Notably, when RRM domains were mutated, the neurons were devoid of TDP-43 puncta suggesting that RNA binding is required for granule formation in axons , mRNA was determined to be absent from many TDP-43 pathological complexes. Lastly, the correlation persisted when TDP-43 RRMs were replaced with the RRM of another RNA binding protein, FUS, suggesting that general RNA binding is sufficient for mitigating toxicity.In support of these recent findings, transient stress was shown to induce long lasting TDP-43 phase separation in the cytoplasm and was independent of mRNA  located within the NLS , however, under persistent stress these assemblies may undergo LLPS and promote the formation of insoluble TDP-43 complexes some of which contain RNAs and some which do not. It is likely that distinct RNA types  have different effects on TDP-43 solubility in cells. We speculate that the type and quantity of RNA available to interact with TDP-43 together with protein-protein interactions shape the type of assembly that TDP-43 associates with, and provide an explanation for the observed heterogeneity. Just reported, a comprehensive mutagenesis screen in yeast identified a 31 amino acid “hot-spot” (312−342) where mutations can cause different degrees of toxicity (Bolognesi et al., SL, EL, RE, and DZ wrote the manuscript. SL made the figure.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


An increasing discrepancy between our experimental results and predictions by theory for increasing Z1 was observed. This observation can be attributed to contributions from energy loss channels different from electron-hole pair excitation in binary Coulomb collisions.We present a thorough experimental study of electronic stopping of H, He, B, N, Ne and Al ions in TiN with the aim to learn about the energy loss mechanisms of slow ions. The energy loss was measured by means of time-of-flight medium-energy ion scattering. Thin films of TiN on silicon with a δ-layer of W at the TiN/Si interface were used as targets. We compare our results to non-linear density functional theory calculations, examining electron-hole pair excitations by screened ions in a free electron gas in the static limit, with a density equivalent to the expected value for TiN. These calculations predict oscillations in the electronic stopping power for increasing atomic number Z The mean energy loss of the ion per unit path length when travelling in a material is usually expressed by the force the medium exerts on the ion, known as the stopping power, S, or more conveniently by the stopping cross section (SCS), ε = S/n, where n is the atomic density. At energies of several hundred keV/u and higher, energy loss is dominated by the energy transfer due to excitation of electrons in binary collisions with the penetrating ion in an otherwise weakly perturbed solid. At lower energies the energy loss process becomes more complex. The projectile may bind electrons, therefore charge state effects must be considered. Consequently, screening of the projectile charge by both projectile and target electrons becomes of importance. With a decrease in ion energy, and consequently of the maximum energy transfer in a binary ion-electron collision, details of the electronic structure of the solid get highly relevant. For the interaction of nuclei multiple scattering effects must be taken into account due to the increase of scattering cross sections6.When an energetic ion moves in matter, it is decelerated due to interaction with the target electrons and nuclei; interactions which are known as electronic and nuclear stopping, respectively. The mechanisms involved in these energy transfer processes are of great interest in many research fields as e.g. ion implantation7. The electronic stopping power Se for ion velocities v <= vF (with vF the Fermi speed) in a target described as a FEG with an effective density ne v, with Z1 the projectile atomic number and Q the friction coefficient8. Density functional theory (DFT) has been extensively used to calculate the stopping power for a FEG with an appropriate density representing the intended material10. These calculations performed for different projectiles predict oscillations in the electronic stopping power as a function of Z113 with a maximum at Z1 ~ 6 and a minimum at Z1 ~ 11 (depending on the effective density) due to the projectile electronic structure. Echenique et al.11. studied the friction coefficients for ions with Z1 from 1 to 18 for different FEG densities. Their results show that the positions of the maximum and minimum shift to higher values of Z1 with decreasing rS. Such Z1 oscillations have been observed experimentally18 and for some materials discrepancies with DFT calculations are observed18.To model inelastic excitations of a solid, a free electron gas (FEG) model can be employed. This model is simple but powerful and has shown to be capable of giving accurate numeric predictions of the electronic stopping powerεe) for H, He, B, N, Ne and Al in TiN by backscattering spectrometry using time-of-flight medium-energy ion scattering (TOF-MEIS) and Monte Carlo simulations. Thin films of TiN grown on silicon with a thin layer of W at the interface, were used in our experiments. The results were compared with SRIM19 results and with nonlinear DFT calculation for a FEG according to Nagy et al.10.In this work we investigate the electronic stopping power of titanium nitride for different ions at energies corresponding to ion velocities below 1 atomic unit (a.u.). We deduced the experimental electronic SCS  with a stoichiometry Ti:N = 1 ± 0.08. The thickness of the W layer is 1.3 ± 0.1 nm. Minor oxygen impurities (below 5%) were observed only on the surface of the sample.For the TOF-MEIS based energy loss investigations we used thin polycrystalline TiN films on silicon, with a W layer of 1 nm nominal thickness at the interface. The sample was prepared by sputtering in a Kurt J. Lesker CMS-18 deposition system by the Department of Engineering Sciences at Uppsala University. The sample was characterized by Rutherford backscattering spectrometry (RBS) and time-of-flight elastic recoil detection analysis (TOF-ERDA) with ion beams of 2 MeV 22, using H, He, B, N, Ne and Al as projectiles with energies in the range of 3 to 140 keV/u. The beams for TOF-MEIS were provided by a Danfysik 350 kV ion implanter. Backscattered particles are detected by a large area position sensitive MCP detector, with a solid angle Ω > 0.1 sr. Only particles detected at scattering angles between 153° and 157° were selected for evaluation, to avoid effects of geometrical straggling. For H and He projectiles, electronic stopping data are obtained from the width of the spectrum signal corresponding to scattering from Ti. For heavier ions, the position of the peak corresponding to scattering from the W δ-layer is used, as shown in Fig. + beam. To account for the influence of multiple scattering and associated nuclear losses, evaluations were performed by Monte Carlo simulation of the experimental data employing the TRIM for Backscattering code (TRBS)23. Note that in the simulations it is also possible to tune the employed potential24. Previous investigations have, however, shown only a very minor impact on the observed spectrum width, even for the case of Ne ions in a heavy matrix such as Au25. The experimental stopping power is now obtained from the TRBS simulation by applying a correction factor to the employed electronic stopping power until a best fit to the experiment is achieved. Note that electronic stopping data for H, He and Ne have been reported by Sortica et al.26. The systematic uncertainty of the deduced electronic stopping from the film thickness calibration by RBS is estimated to be ~4% due to possible residual channelling in the substrate, accuracy of the employed stopping power for MeV He in Si and experimental statistics. In the MEIS experiments, no evidence for channelling of ions backscattered from TiN could be observed. The statistical uncertainty due to the fitting procedure using TRBS is estimated to be below 2%. Considering other possible uncertainties due to film stoichiometry, binning effects, etc., the accumulated uncertainty of our deduced electronic stopping cross sections should be below 7%.To obtain energy loss data, we performed TOF-MEIS experiments at the setup at the Ångström Laboratory in Uppsalaεe for all investigated projectiles together with the corresponding SRIM results for ion velocities v up to 1 a.u.. For H and Ne projectiles, εe is observed to be proportional to v. For He, B and N, εe exhibits a linear dependence on v extrapolating to a positive offset at zero velocity. For Al projectiles, at the lowest energies a clear non-linear dependence of εe on the ion velocity is observed. Note, however, that experiments for heavier ions at lowest energies have highest systematic and statistical uncertainty due to the evaluation procedure being more affected from nuclear losses.Figure et al.10. The density parameter rS = 1.61 a.u. for the FEG (which corresponds to ~7 electrons per molecule) was obtained from the experimental plasmon energy of TiN27. On this basis, for protons, excellent agreement with DFT predictions has been found26. Note, that the electronic structure of TiN, although being a metallic compound, is significantly different from a FEG28. Also, it has been recently shown, that for heavier early transition and rare-earth elements the DFT-model has failed as unreasonably high electron densities would have been required29. For all projectiles heavier than hydrogen, DFT calculations systematically underestimate the experimental data. To present the electronic stopping cross section as a function of the projectile atomic species and to allow for a clear comparison with theory, our results are expressed in terms of et al.11. For each Z1, εe is obtained from the corresponding plot shown on Fig. v for v < 1 a.u. Figure Z1* and experimental values for H, He, B, N and Al as a function of Z1. Oscillations in Z1* are present in the calculations due to screening effects and the atomic structure of the projectile11. To allow for an additional comparison with the model by Lindhard and Scharff30 as well as the modified Firsov-formula31 we have plotted their respective predictions as dashed and dash-dotted lines respectively. As both models ignore the shell structure of atoms and thus by definition are incapable of reproducing possible Z1-oscillations in dE/dx, both predict a monotonic increase in Z1*. Note, that also the observed slopes are significantly different from the experimental observations. When comparing with DFT, as already mentioned, except for protons, the calculated stopping power is always found lower than the experimental data, with increasing discrepancy for increasing Z1. In contrast to predictions, our data exhibit a broad maximum close to the calculated minimum, which has been attributed to atomic numbers corresponding to full atomic shells of the projectile. However, results obtained in grazing surface scattering on LiF confirm the predicted Z1 oscillations very well18. This qualitative difference in the Z1-dependence of electronic stopping of slow ions in surface scattering and in a solid points towards an additional energy loss mechanism in the latter case. Such a process should have high efficiency for ions with atomic numbers close to full atomic shells and is expected to occur for comparably small impact parameters. We suggest electron promotion in atomic collisions between dressed atoms as explanation. In collisions of both, charged or neutral projectiles with a target atom, promotion of electrons due to Pauli repulsion will provide an efficient mechanism of ionization32. In parallel, a formation of molecular orbitals at short interaction distances with an associated modification of the total energy of the electronic system can be expected33. Both processes can lead to electronic energy loss independent from electron-hole pair excitation in a Coulomb collision, and, therefore, increase electronic stopping.The deduced values of the stopping cross sections are subsequently compared to nonlinear DFT calculations for a FEG according to Nagy Z1-dependence of electronic stopping is supported by the observed deviations from velocity proportionality for ε for some of the projectiles. The relevance of atomic collisions is corroborated by the fact that inner shell excitation of the target material is observed even for low energy He projectiles35. As a consequence, repeated charge-exchange cycles and internal excitations of the projectile will occur and contribute to the electronic stopping power, as has been observed for He and Ne ions at energies significantly below 10 keV37. A possible influence of these processes on the velocity scaling of the electronic energy loss observed for He ions in Al and Au has been reported39. Note that electron transfer in atomic collisions can lead to substantial energy transfer that clearly exceeds the maximum energy transfer in a binary ion-electron collision35.The proposed interpretation of the et al.26 are compared with predictions from theory, in particular non-linear DFT calculations for a FEG. For protons, DFT-calculations perfectly reproduce the experimental data26, which indicates that in this case electronic stopping is dominated by direct excitation of conduction electrons of TiN in binary ion-electron collisions. For heavier ions, the discrepancy between predictions by theory and experimental data is found to increase with the projectile atomic number. For these ions, direct electron-hole pair excitation in binary collisions is apparently insufficient to explain the observed increase in the stopping cross sections. More complex dynamic energy transfer processes are expected to be responsible for the apparent discrepancy between static theory and experiment. Time dependent DFT calculations, including contributions of inner shells and the projectile electronic structure may lead to a better understanding of energy-loss processes of ions in TiN.In this work, electronic stopping cross sections for B, N and Al in TiN have been measured. Experimental results, including H, He and Ne from Sortica


Finally, the future challenges and prospects of graphene hybrid materials gas sensors in this field are discussed.Graphene and its hybrid materials, due to their unique structures and properties, have attracted enormous attention for both fundamental and applied research in the gas sensing field. This review highlights the recent advances in the application of graphene-based gas sensors in fault characteristic gas detection of oil-immersed equipment, which can effectively achieve condition monitoring of the oil-immersed power equipment. In this review, the synthetic methods of graphene hybrid materials with noble metals, metal oxides and their combination are presented. Then, the basic sensing mechanisms of graphene hybrid materials and gas sensing properties of graphene hybrid materials sensors to hydrogen (H Paton et al.  developen et al.  successf2 sensing using a polymer-assisted hydrothermal method and the H2 sensor had a response value of 16% and response/recovery times of 9/10 s with a 1% H2 concentration at 200 °C. Semiconductor metal oxide such as SnO2 , testing chamber and computer-controlled data acquisition and analysis system, as presented in Figure 2O molecules with hydrogen bonds and the adsorbed H2O molecules are transferred to H3O+, further promoting the formation of ion channels on the surface of the sample. When they are in contact with adsorbed molecules, the hydrogen bonds will be destroyed, which inhibits the ionization reaction between oxygen functional groups and H2O molecules and leads to step-like changes in resistance , the sensing behavior can be explained by the surface-adsorbed oxygen  will capture electrons from the surface of metal oxide to form chemisorbed oxygen species , which leads to a high resistance of the sensor, as observed in the experiments . In this section, we summarize and discuss the related works based on the recently published papers  at room temperature. Wang et al. synthesized MoO3 nanoribbon/graphene hybrid for H2 sensing with ultralow LOD of 0.5 μL/L  and recovery (~15 s) at 90°C. Shojaee and co-workers synthesized Pd-loaded SnO2/rGO hybrid materials by a hydrothermal method for CO sensing application /graphene  may be generated when electrical or thermal failures occur, such as oil or high-temperature overheating, partial discharge, spark discharge, or arc discharge. These four hydrocarbon gases have a small difference in molecular structure and chemical composition, and the sensing materials usually have the similar response to them. According to the relationship between principle gases and associated fault types  /graphene. Due to the existence of the π-π* conjugation system within the PANI/graphene, this sensor showed a high sensitivity of 10–3,200 μL/L at room temperature (Wu et al., 4 against H2, CO, and CO2. The response to 100 μL/L CH4 was 2.2% at 260°C. Graphene hybrid with ZnO (Zhang et al., 2 (Navazani et al., 4 around 190 and 150°C. Nasresfahani et al. (2/rGO via hydrothermal route, and the sensing performance to 800–16,000 μL/L CH4 were carried out at room temperature. Gas sensing characteristics of C2H2 sensor based on SnO2/rGO were carried out for 0.5–500 μL/L C2H2 at 180°C. The p-n heterojunctions between SnO2 and rGO, oxygen functional groups and high specific surface area of SnO2/rGO hybrid materials contribute to the high performance of sensor (Jin et al., 2/rGO (Jiang et al., 2H2 sensing. However, with the decrease of operating temperature, the sensitivity of the sensor was reduced with longer response-recovery time.The hydrocarbon gas (CHi et al.  synthesiGraphene hybrids are distinctive and promising sensing materials for detection of various gases, due to their ultrahigh electron mobility and large specific surface area. Compared to other types of sensor, the graphene-based sensors exhibit excellent properties and provide a new idea for high sensitivity detection of the oil-immersed power equipment at low temperature.Although great progress has been made in this field, there are still many challenges that need to be addressed. First, lower LOD and faster response-recovery time are needed. Graphene-based sensors provide a possible approach to detect gases at room temperature, but the reaction activities between gas molecules and sensing materials may be reduced, especially during the desorption, making it difficult to meet the engineering requirements. Ultraviolet light assisted excitation technology and novel multi-dimensional hierarchical nanostructure of graphene hybrid materials are useful ways to solve this problem. Secondly, avoiding the cross-sensitivity in the detection of mixed gas. Gas sensors usually exhibit similar responses toward different gases of different concentrations. The functionalization of graphene, operating temperature modulation and design of filter layer are workable methods to overcome this challenge. Moreover, gas sensor arrays, composed of group of sensors and signal processing algorithms, can realize the qualitative identification and quantitative detection of mixed gas. Thirdly, developing more stable materials and sensors. In practical application, the condition of detection environment, such as vibration, temperature, humidity, and other contaminants, may affect the sensitivity of sensors. The improvement of sensing materials, coating method, and fabrication techniques can avoid or reduce the impact of these factors. Finally, the development in this field is inseparable from the research of new materials as well as the corresponding sensing mechanism.WC and LJ summarized and analyzed the related literature. LJ wrote the manuscript under the guidance of YZ and WC. All authors read and approved the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


We determined the diagnostic and therapeutic effects of SRM-IV vestibular function diagnosis and treatment system on benign paroxysmal positional vertigo (BPPV).Overall, 120 patients with BPPV diagnosed in the outpatient and in-patient departments of the Vertigo Treatment Center of the First People’s Hospital of Xuzhou from January 2013 to December 2015 were selected for this study. They were randomly divided into three groups. Automatic repositioning procedure was conducted for 40 patients in the equipment repositioning group by SRM-IV vestibular function diagnosis and treatment system, conventional manual repositioning procedure was used for 40 patients in the manual repositioning group, and combination of treatment drugs  with acclimatization training was adopted in 40 patients in the drug therapy group.P<0.05). The total effective rate was 100.0% in the equipment-repositioning group and 92.5% in manual repositioning group; the difference between the two groups was not statistically significant. The success rate of one-time treatment of anterior semicircular canal BPPV, posterior semicircular canal BPPV and lateral semicircular canal BPPV in the equipment-repositioning group were higher than those in the manual repositioning group were.After 1 week of treatment, the cure rate and total effective rate in the equipment repositioning group and the manual repositioning group were significantly higher than those in drug therapy group (The SRM-IV vestibular function diagnosis and treatment system are helpful in achieving effective and standard diagnosis and treatment of BPPV. Benign paroxysmal positional vertigo (BPPV) is a common type of vertigo with a high incidence rate, and accounts for 17–20% of peripheral vertigo. BPPV, however, is often misdiagnosed as cerebrovascular vertigo and cervical vertigo, and unnecessary economic and psychological burdens are added to patients if inappropriate examination and treatment are administered. Canalith repositioning procedure can alleviate patients’ symptoms rapidly and relieve the pain of vertigo patients.Currently, the manual repositioning procedures consist of Barbecue rotation therapy, Epley procedure, Semont procedure and Gufoni procedure, but the clinical efficacy of each treatment is not stable as there are problems in the manipulative standards and physician’s experience in clinical practices . SRM-IV Our clinical study utilized automatic SRM-IV vestibular function diagnosis and treatment system for diagnosis and repositioning treatment on BPPV patients as well as the conventional manual repositioning procedure for comparison analysis, in order to explore effective therapeutic methods for BPPV.Overall, 120 patients with BPPV that were diagnosed in the outpatient and in-patient departments of the Vertigo Treatment Center of the First People’s Hospital of Xuzhou from January 2013 to December 2015 were selected for this study. All patients underwent imaging examinations including magnetic resonance imaging (MRI) or cranial computed tomography (CT) in order to exclude new cerebral infarction and cerebral hemorrhage. Patients also received routine neuro-otology tests to exclude vertigo caused by other problems in the nervous system and labyrinth.This study was approved by the Ethics Committee of the First People’s Hospital of Xuzhou. The informed consent was signed by all patients and their families.The patients were divided into 3 groups by the random number table. Automatic repositioning procedure was conducted for 40 patients in equipment repositioning group by SRM-IV vestibular function diagnosis and treatment system.Manual repositioning procedure was used for 40 patients in the manual repositioning group. Lastly, treatment-combining drugs with acclimatization training was administered to 40 patients in drug therapy group.P>0.05) and were therefore comparable.In the equipment repositioning group, there were 13 males and 27 females aged 24–80 years old, with an average age of 45.21±12.36 years old. The duration of disease was ranged between 15 days and 8 years, with an average duration of 2.23±3.61 years. In manual repositioning group, there were 14 men and 26 women aged 23–76 years old, with an average age of 44.83±12.50 years old. The duration of disease was ranged between 4 days and 9 years, with an average duration of 2.15±3.07 years. In the drug therapy group, there were 15 males and 25 females aged 21–79 years old, with an average age of 43.16±12.44 years old. The duration of disease was between 11 days and 7 years, with an average duration of 2.22±3.13 years. The statistical processing of the general data in two groups of patients confirmed that the differences were not significant  and safflower injection  with acclimatization training was administered in the drug therapy group. Alprostadil (10 μg) was mixed with 100mL normal saline and then infused intravenously once a day. Aafflower injection (20mL) was mixed with 250mL normal saline and then infused intravenously once a day. Seven consecutive days of drug administration were taken as a course of treatment. The acclimatization training could reduce the symptoms induced by special movement by means of repeated head and visual movement.SRM-IV vestibular function diagnosis and treatment system was utilized in the equipment-repositioning group, and all patients accomplished the roll test and Dix-Hallpike test on the system. Anterior semicircular canal BPPV: The patient was seated in the straight-ahead position and the whole body was turned left or right 45° and remained for 1second. Then, it leaned forward 120° within 1.5s to observe the disappearing of nystagmus and vertigo. After that, the body was turned 110° and remained there for 60s to observe the disappearance of nystagmus and vertigo. The body was continuously turned 130°, back to the starting position. Posterior semicircular canal BPPV: The patient was seated in the straight position, and the whole body was turned left or right 45° and remained there for 1second. Then, it was leant backward 120° within 1.5 s to observe the disappearance of nystagmus and vertigo. After that, the body was turned 110° and remained for 60s to observe the disappearing of nystagmus and vertigo. Then, the body was further turned 130°, back to the starting position. Lateral semicircular canal BPPV (cupulolithiasis type) of the right side: The patient was seated in the straight position and then slowly rotated to the supine position with the head risen 30°. The patient turning to the left 90° was taken as the starting position of repositioning procedure. The whole body was turned to the right 90° within 1.5 seconds and remained for there for 60s to observe the disappearance of nystagmus and vertigo. Again, it was turned to the right 90° within 1.5s and remained there for 60s to observe the disappearance of nystagmus and vertigo. Then, the body was turned to the right 90° and remained there for 60s to observe the disappearance of nystagmus. After that, the patients were further turned to the right 90° and remained there for 60s to observe the disappearance of nystagmus, and then were finally back to the starting position. Lateral semicircular canal BPPV (cupulolithiasis type) of the left side: the patient was seated in the straight position and then leaned towards the left side rapidly for 90° within 1.5 seconds and remained for about 180s to observe the disappearance of nystagmus and vertigo. Then, the body was turned to the right for 90° C within 1.5 s and remained for there for 60 s to observe the disappearance of nystagmus and vertigo, and then the patients were returned to the starting position. The process was repeated twice.The patients in the equipment repositioning group and the manual repositioning group were reexamined 48 hours after treatment, in which roll test or the Dix-Hallpike test was performed again to determine whether there was nystagmus and vertigo in patients. The second repositioning treatment was carried out on patients with positive provocative tests, further consultation was conducted after 1-week of observation, and the clinical efficacy was assessed. If symptoms were relieved in drug therapy group 1 week after treatment combining drug administration with acclimatization training, the one-time treatment was successful.Diagnosis Basis and Curative Effect Appraisal of Benign Paroxysmal Positional Vertigo  formulated by the Chinese Otorhinolaryngology Head Surgery Society of Chinese Medical Association in 2007  was used for data processing, and chi-square test was applied to the comparisons of indexes. P<0.05). There were no significant differences between the equipment repositioning group and the manual repositioning group (P>0.01).The statistical results of clinical efficacy in three groups of patients after 1 week of treatment are shown in Upon reexamination 1 week later, patients in the manual repositioning group, who were treated by the equipment repositioning procedure, exhibited that they were cured.P>0.001), however, the success rates of one-time treatment in the equipment repositioning group were higher than those in manual repositioning group were.In the equipment-repositioning group, there were 5 cases of anterior semicircular canal BPPV, 22 cases of posterior semicircular canal BPPV and 13 cases of lateral semicircular canal BPPV. In the manual repositioning group, the number of cases of anterior, posterior and lateral semicircular canal BPPV was 4, 23 and 13, respectively. The success rates of one-time treatment of different types of BPPV in the two groups are shown in BPPV is one of the most common peripheral vestibular disorders with complains of vertigo, which was first discovered by the physiologist Bárány in 1921 . The speThere are three pairs of semicircular canals in the human body located in three planes, which are relatively perpendicular to each other. The automatic SRM-IV vestibular function diagnosis and treatment system can maximize stimulation on the semicircular canal by corresponding the movement mode of the plane in which the semi-circular canal is located. Adequate stimulation on the semicircular canal may lead to the occurrence of positioning nystagmus, and the direction of nystagmus has a corresponding relationship with the stimulated semicircular canal , 8. The In the conventional manual repositioning procedure, problems associated with changing body position can easily to occur, positioning nystagmus cannot be guided in the patient, and a false negative state may easily to happen . MeanwhiWe observed through our study that, after 1 week of treatment, the total effective rates in both the equipment repositioning group and the manual repositioning group were above 80%, and the cure rates and total effective rates in both groups were significantly higher than those in the drug therapy group, which proves that both automatic SRM-IV vestibular function diagnosis, treatment system and manual repositioning procedure can effectively alleviate the symptoms of positioning nystagmus and vertigo in patients with BPPV. However, the cure rate and total effective rate in the equipment-repositioning group were higher than those in manual repositioning group were. In addition, patients in the manual repositioning group that were treated by the equipment repositioning upon reexamination 1 week later exhibited that the manual repositioning procedure was ineffective, but were cured by equipment repositioning. We also demonstrated in The automatic SRM-IV vestibular function diagnosis and treatment system has realized the full automation and standardization of conventional manual induction and repositioning procedure in terms of localization, quantification and speed fixing, so that 100% of therapeutic effect can be achieved. Therefore, it can provide an accurate basis for clinical diagnosis and treatment of BPPV and can implement standard operations. Thus, it is suitable for popularization and application in clinical practices.Ethical issues  have been completely observed by the authors.


Graphene nanocomposite is an inorganic nanocomposite material, which has been widely used in the treatment of tumor at present due to its ability of drug loading, modifiability, photothermal effect, and photodynamic effect. However, the application of graphene nanocomposite is now limited due to the fact that the functions mentioned above are not well realized. This is mainly because people do not have a systematic understanding of the physical and chemical properties of GO nanomolecules, so that we cannot make full use of GO nanomolecules to make the most suitable materials for the use of medicine. Here, we are the first to discuss the influence of the physicochemical properties of graphene nanocomposite on the various functions related to their antitumor effects. The relationship between some important physicochemical properties of graphene nanocomposite such as diameter, shape, and surface chemistry and their functions related to antitumor effects was obtained through analysis, which provides evidence for the application of related materials in the future. At present, graphene materials are often used in the form of graphene nanocomposites for biomedical and clinical practice. Graphene nanocomposites with the basic structure of GO have some special effects of common nanomaterials, such as small size effect, which enables the materials not only to have an excellent photothermal effect to convert infrared light energy into heat energy effectively due to the special effects mentioned above and the presence of a large number of aromatic ring structure [π-π stacking [As a deadly disease, cancer has always caused a great threat to people's health , 2. In ttructure –16, but stacking , 18. Grastacking , photodystacking , and so stacking , 21. OurGraphene nanocomposites have a variety of special properties, such as photothermal effect, photodynamic effect, and drug loading effect. Whether these properties can be successfully applied to the practice of eliminating tumor cells is closely related to the physical properties of the material molecules. At present, we pay more attention to the physical properties of material molecules. In the following part, some basic and important physical properties of graphene oxide nanocomposites currently in use and research such as shape, size, and surface potential will be introduced in detail, and the influence of these physical properties on the antitumor use of nanomaterials will be discussed.The shape of nanometer molecule is not a parameter that can be measured, but its influence on nanometer material molecule is self-evident. The European Union's new guidelines on nanomaterials state that shape is one of the key parameters in the definition of “nanoform” . The US The molecular size of GO nanocomposites is one of the most important physical properties. Many unique properties of nanomaterials are determined by their molecular size. Because the size or diameter of nanomolecule is in the nanometer, the nanomolecule has a high surface area ratio and quantum size effect, so that the properties of nanomolecule have a significant difference compared with other common materials . Many iner cells . It has er cells . Howeverer cells , which mThe diameter of nanometer molecule can also affect its photodynamic effect. The application of photodynamic effect in antitumor therapy is a new way of thinking which is different from photothermal therapy . PhotodyBesides, the molecular size of nanomaterials not only plays an important role in the functional realization of nanomaterials, but also influences the toxicity of nanomaterials and the body's immune response to nanoparticles. Studies have shown that the toxicity of GO nanomolecules is related to their molecular size . SchinwaIt should be pointed out that there are still some problems in determining the shape and size of GO nanoparticles. For example, proteins immediately attach themselves to nanomaterials after they come into contact with them, creating the so-called protein corona around the nanomaterials , 59. TheSurface potential is an important physical quantity of nanomolecules. We can detect the surface potential of nanomolecules through the measurement of surface zeta potential. Zeta potential of GO nanomolecules is one of the physical quantities frequently measured in experiments. One reason that zeta potential is particularly significant is that it could affect the dispersion of graphene oxide nanomolecules. Some studies indicate that particles with zeta potential between -30 and + 30mv tend to condense, which is most obvious when the solution is at an isoelectric point, when zeta potential of nanomolecule is 0mv . CurrentThere are also many other physical properties of nanomolecules, such as superparamagnetism, porosity, and dust content. These physical quantities also have a great influence on the properties of nanomolecules, but these physical properties do not play a critical role in drug loading, photothermal effect, and photodynamic effect. Therefore, the authors believe that it is not necessary to measure the characterization of nanomolecules in detail in experiments. At present, most researches on nanomaterials have not reported many other properties of nanomaterials. With the in-depth studies of nanomolecules, more physical properties may be paid attention to in the future.The chemical properties of GO nanomolecules that we focus on are the surface chemical properties. The rich chemical properties of GO provide us with more opportunities for modification and drug delivery. As we all know, functionalized nanographene can be used as a drug carrier to deliver anticancer chemotherapy drugs and gene therapy for tumors in vitro , 72–74. π-π bonds, such as drug carrying capacity, are probably affected. Therefore, it can be seen that the biological functions of GO nanoparticles are inseparable from their inherent surface chemical properties. These surface modifiers also play an important role in the photodynamics of GO nanoparticles [The presence of these functional groups can transfer negative surface charges and inhibit irreversible lamination in solution , which earticles .However, graphene oxide nanomolecules are not suitable for biomedical applications if only due to their own chemical properties. Therefore, we often modify graphene nanomolecules with some molecules, such as chitosan, PEG, and albumin. The addition of these molecules will have a certain impact on the chemical properties of GO nanomolecules. Some representative modifying molecules are discussed in detail in the following subsections.It is well known that the protein “corona” is easily attracted by nanomolecules when they enter the body due to hydrophobic, electrostatic, and van der Waals interactions, as well as the hydrogen bond between NPs and proteins –85. ThisAt present, antitumor chemotherapy drugs are generally cytotoxic. Taking adriamycin as an example, it has low tumor cell selectivity and strong cardiac toxicity –97. TherThere are many other molecules that can be used to modify GO nanoparticles, such as chitosan, to perform different functions. Through chemical modification, we can subjectively modify graphene oxide nanomolecules to increase their functions, which is a highlight of graphene oxide applications.With the development of medical technology, the cooperation between medicine, material science, and chemistry has become more and more, and the interdisciplinary has become a suitable choice to make a new breakthrough in the related fields. The application of graphene oxide nanomolecules in antitumor effects is a representative achievement of the intersection of medicine, materials science, and chemistry. GO nanoparticles are modifiable and have good photothermal and photodynamic effects, which provides a good idea for targeted killing of tumors. Nowadays, graphene oxide nanomolecules have been applied in many antitumor researches. Scientists have carried out various chemical modifications and physical properties control, loaded with different antitumor drugs to kill tumor cells, and achieved certain research results. In the process of application, we found that determining the chemical and physical properties of nanoparticles is a critical step. A lot of special properties of graphene oxide nanometer carrier, such as thermal effect and ability of carrying drugs, are all related to the physical and chemical properties of the nanoparticles, and a multitude of graphene oxide surface oxygen groups are left for us to modify, so as to enrich the nature of nanoparticles. It can be concluded that the development of graphene oxide nanomolecular applications will be based on the understanding, utilization, and expansion of its rich physical and chemical properties.