The commensurability condition is applied to determine the hierarchy of fractional fillings of Landau levels in monolayer and in bilayer graphene. The filling rates for fractional quantum Hall effect (FQHE) in graphene are found in the first three Landau levels in one-to-one agreement with the experimental data. The presence of even denominator filling fractions in the hierarchy for FQHE in bilayer graphene is explained. Experimentally observed hierarchy of FQHE in the first and second Landau levels in monolayer graphene and in the zeroth Landau level in bilayer graphene is beyond the conventional composite fermion interpretation but fits to the presented nonlocal topology commensurability condition.  SU(4) spin-valley symmetry is broken by a larger magnetic field, the new features for IQHE appear, corresponding to removal of LL subbands degeneracy [Recent progress in Hall experiments with graphene has revealed many new features in longitudinal and transversal resistivity in Hall configurations characteristic for fractional quantum Hall effect (FQHE), both in suspended graphene scrapings –3, and igeneracy . In the graphene . EspeciaIn the present paper we analyze the hierarchy for fractional fillings linked to strongly correlated multiparticle states in graphene using the topological commensurability approach developed earlier for the ordinary 2DEG Hall systems –10. In t2. N-fold normal product of the manifold N elements [N particle system resulting in special shapes of trajectories are not important here, unless they cause the topological nonequivalence. Only topology of trajectories on M decides whether one trajectory loop can be continuously transformed into another one without a cut or not. If a smooth continuous transformation is impossible between two trajectories, they are topologically nonequivalent and fall into distinct classes of the full braid group. Thus, the full braid group does not reflect the dynamics details, but rather identifies the topology restrictions imposed on the multiparticle system, which are associated to some global features of the system including the manifold type and only those aspects of interaction that might cause topological nonequivalence of trajectories. The Coulomb repulsion of electrons on the plane is a central prerequisite for the braid group definition at magnetic field presence, because the scale of interparticle separation defined by the Coulomb repulsion must interfere with the planar cyclotron orbits, discriminating in this way possible correlation types. As the loops from i-th particle on the manifold M, i.e., the classical position of the i-th particle on M) are changing along a selected loop from the The concept of the commensurability of cyclotron trajectories with interparticle spacing in a 2D charged system at strong magnetic field is born in relation to the braid group approach to multiparticle systems in the presence of a magnetic field, and employs the interaction of electrons, essential for formation of any correlated state, including states corresponding to FQHE. The collective behavior of a quantum multiparticle state must be assigned by the statistics phase shift acquired by the multiparticle wave function if one considers position exchanges of particle pairs ,13. The elements . The quoar braid . In thisnt 1DURs :(1) σi→ei-th and M the braid groups differ considerably from the permutation group. For where he 1DURs :(2) σi→ecorresponding to so-called anyons . This is illustrated in the central panel of Figure BA must be shared among three loops with the same surface A (i.e. BA for each loop). Thus, each loop accommodated to the flux quantum A and gives the contribution BA to the flux, resulting in the total flux 3BA per particle, as needed – this is schematically illustrated in Figure A in the right panel is equal to A in the left panel, which means that the three-loop orbits fit to the interparticle separation.In Figure As the braid group generator must be defined by the half of the cyclotron orbit . The genductors .x-th particle separation  is here 4. This corresponds to the ordinary Zeeman spin-splitting and to the so-called valley splitting (expressed often in terms of a pseudospin) due to doublet of inequivalent K points mixed with two sublattices for C atoms in crystal lattice of graphene [In graphene one deals with the relativistic version of LLs ,23. Thisnds meet . Thus thgraphene  and the rvations . The remThe Berry phase contribution is linked to an additional Similar analysis of the LLs can be done for the bilayer graphene ,24. Due  and n=1 ,24. Beca the LLs ,24.3.1. For the magnetic field strong enough that The cyclotron orbits in the LLL must be accommodated to the bare kinetic energy S is the sample surface). As this orbit size is lower than the interparticle separation l-th particles. In this way one can obtain the hierarchy of fillings for FQHE in this subband of the LLL, q-looped orbit x-th particle . For hoFor the completely filled subband x-th particle) we get Similarly one can consider fillings of the following LL with At the special case q-looped orbits, their size may be accommodated to every x-th particle in the subband, resulting in additional hierarchy in all subbands of the first LL, Moreover, for , ν=23,4,+xll3(q-1n), whereas the interparticle distances are measured with the plaque The following subbands are filled with electrons upon the similar scheme. For the subband 3.2. The special topology of the bilayer graphene creates the opportunity to verify the braid group based concept of the commensurability of cyclotron orbit size with the interparticle spacing in the planar system of interacting particles. Let us emphasize once more that the interaction is essential for correlation manifestation – the interaction prevents particles from approaching one another closer than the particle separation resulting from the planar density. This separation is rigidly kept by the interaction allowing the commensurability notion to be useful. Exclusively when the cyclotron orbits fit accurately to the particle spacing the exchange of neighboring particles in the presence of the perpendicular magnetic field is possible along specific braids named as the cyclotron braids.It must be emphasized that commensurability condition, as related to the braid group, concerns the classical archetype of the quantum system, thus is not addressed to real quantum particles which do not have any trajectories. This agrees with the spirit of the braid group approach in which classical trajectories in configuration space supply information on quantum statistics via 1DURs of the braid group. To organize any correlated collective state, the related statistics of particles must be determined first. In order to establish the statistics of quantum particles, the appropriate braid group must be defined whereas the statistics is governed by the selected 1DUR of this group .The bilayer graphene is, however, not strictly two dimensional and for the bilayer graphene the topological situation changes considerably. Two sheets of the graphene plane lie close to each other and the hopping can change the electron positions among the planes. Thus, we deal here with double the number of electrons residing on a two-sheet structure simultaneously instead of the single sheet as was the case for the monolayer graphene.doublelooped cyclotron orbits may have in bilayer graphene the same size as the single-looped orbit in opposition to the monolayer case. This follows from the fact that the second loop can be located in the opposite sheet of graphene than the first one and the external field passing through such doublelooped orbit is twice larger than the flux passing through the single-looped orbit. Each loop has in this case its own separate surface in contrary to the multilooped cyclotron orbit located on the purely 2D plane. Taking into account that in the bilayer system loops of the multilooped orbit may be located partly in both 2D sheets, the contribution of the one loop must be avoided whereas the remaining loops must share the same flux as passing through a single-looped orbit, independently of how loops are distributed among two sheets. Thus, one can write out the commensurability condition in the bilayer graphene for the case of too short single-looped cyclotron orbits in the following form , and p is an odd integer to assure that the half of the cyclotron orbit defines the braid.where, p-looped cyclotron orbit take part only The factor Equation  is causep – thus the generators of the corresponding cyclotron subgroup are of the form p exponent for the Jastrow polynomial. But due to the distinct commensurability of orbits with interparticle separation (Equation (p-odd) in the first particle-type subband of the LLL, i.e., in the subband Let us emphasize that for such multilooped orbits the total number of loops is still Equation ) the reln due to the same size of the cyclotron orbits.For holes in this subband  one can write Some novelty occurs, however, in the following two subbands of the LLL, The generalization of this main series for holes in the subband and to the full FQHE hierarchy in this subband is as follows: for subband holes, In the subband The last subband The evolution of the fractional filling hierarchy of subsequent LLs is illustrated in Figures For bilayer graphene the degeneration of One can consider also the situation in the LLL of bilayer graphene, when the degeneracy of ∗<1 , it wasce band) ,29. Both011 cm-2 ; and in FQHE in suspended graphene is observed at relatively high temperatures around 10 K , and eveThe competition between the FQHE state with the insulator state near the Dirac point, corresponding to a rapidly decreasing concentration has also been demonstrated ,33 Figu.From the perspective of cyclotron groups, experimental results on FQHE in graphene –31,34 se5-60 V ) allows 5-60 V ,29. For 5-60 V . In the 5-60 V  may exhiBN) in high magnetic fields of the order of 40 T  .The mobility of carriers in graphene is lower than in traditional 2DEG, but taking into account that the carrier concentration in graphene can be lower in comparison to semiconductor heterostructure ,38, the Energy gaps protecting incompressible FQHE states are larger in graphene than in traditional semiconductor materials, reaching a magnitude in order of 16 K  , the subn. The repeating doublet of filling ratios for If one compares the experimentally observed fractions for characteristic FQHE features in longitudinal and Hall conductivities measured on a variety of samples of graphene with the pattern of fractional hierarchy for two lowest LLs, as illustrated in Figure le-loop) –5. The n3), 133,13, , 3,113, -rates indistinguishable at the observation resolution. In higher LL the new features, however, occur in between the above-mentioned doublets, but with nonzero longitudinal resistivity contrary to other FQHE states. This suggests that not all particles participate in these correlated states and they may correspond to the multilooped correlations of every second or every third particles according the appropriate cyclotron commensurability. And indeed these new features in the first LL of monolayer graphene, recently reported  at ν=73,N, B)-plane in Figure N, B)-plane. Straight lines, which lie in a -plane and have a common point in a coordinate origin, are connected to a constant filling factor value; N, B)-plane can be described as n enumerating LL, b depending on n and LL degeneracy, first n and compressed to smaller periods for higher n, which also agrees with the details of the observation [Another experimental evidence for the above hierarchy follows from the measurement  of the tervation . SimilarThe most convincing evidence supporting the correctness of the commensurability condition is, however, the coincidence of the related predictions with the experimental observations in bilayer graphene. The pronounced feature of these observations is the occurrence of primary fractional features with even denominators also in the lowest subband of the LLL in bilayer graphene, oppositely to monolayer one . The comNote finally that the FQHE hierarchy in bilayer systems with the characteristic even denominators holds also for bilayer 2DEG conventional Hall setups and indeed the ed there ,41, whic5. The condition for commensurability of cyclotron orbits building cyclotron braid subgroups with interparticle spacing in homogeneous 2D charged systems is formulated in order to verify possibility of arrangement of correlated multiparticle Hall states. Using this commensurability condition based on the braid group approach to statistics of interacting many particle systems, the hierarchy of fractional fillings for LLs in graphene has been determined. The FQHE evolutionwith growing numbers of LLs has been described. In higher LLs the new opportunities for commensurability occur leading to the different than the ordinary FQHE(multiloop) correlated states. The fractional fillings of LLs related with this new commensurability opportunity have been identified, starting from the first LL. They are referred to FQHE(single-loop) because the related correlations are described by single-looped braids. Both the monolayer and bilayer graphene have been considered and the essential difference of related hierarchy structures has been demonstrated and described. The even denominator main line of the fractional filling hierarchy in bilayer graphene is found in agreement with the experimental observations. The confirmation of the presented hierarchy for the monolayer and bilayer graphene can be found in experimental data for both, the graphene on BN substrate as well as the suspended samples including bilayer graphene available for fillings up to sixth spin-valley subband.The success in description of hierarchy for FQHE using commensurability conditions is linked with the nonlocal and topological character of this approach. It is known that FQHE results from non-perturbative effects of the Coulomb interaction in 2D, which give rise to gapped many-body states at special filling factors. These states have long-range entanglement and cannot be explained in a simple single-particle picture. Similarly, the composite fermion theory, effective in the LLL of conventional 2DEG and in monolayer graphene, is in fact not strictly local, utilizing the auxiliary concept of flux tubes, or vortices, fixed to particles and allowing via this multiparticle effective trick to discriminate highly nonlocal effects. The commensurability approach presented in this paper bases on the topological braid group description of statistics in many body systems and falls to the same class of nonlocal multiparticle models. It elucidates artificial assumptions of composite fermion theory and allows for the generalization of the topological approach beyond the limit of the composite fermion model. In particular, the commensurability approach is effective also in higher LLs and allows the hierarchy of FQHE to be defined quite differently than that in the LLL – in agreement with experimental observations. Utilizing the energy minimization methods , the difference between FQHE states belonging to various Landau levels is referred to the different form of the effective Coulomb interaction (i.e. Coulomb interaction dressed by the form factor corresponding to a given Landau level). The energy minimization gives energy gaps for fractions related to special multiparticle correlations of FQHE. These fractions (and their hierarchy) can be, however, identified by a nonlocal effective-multiparticle topological method of commensurability braid approach, generalizing in this way the previous composite fermion approach from the LLL. The advantage of the commensurability condition is especially clearly visible in the case of bilayer graphene, where the states at fractions with even denominators cannot be explained by the simple composite fermion model, even in the LLL.


Smart actuators have many potential applications in various areas, so the development of novel actuation materials, with facile fabricating methods and excellent performances, are still urgent needs. In this work, a novel electromechanical bimorph actuator constituted by a graphene layer and a PVDF layer, is fabricated through a simple yet versatile solution approach. The bimorph actuator can deflect toward the graphene side under electrical stimulus, due to the differences in coefficient of thermal expansion between the two layers and the converse piezoelectric effect and electrostrictive property of the PVDF layer. Under low voltage stimulus, the actuator  can generate large actuation motion with a maximum deflection of about 14.0 mm within 0.262 s and produce high actuation stress (more than 312.7 MPa/g). The bimorph actuator also can display reversible swing behavior with long cycle life under high frequencies. on this basis, a fish‐like robot that can swim at the speed of 5.02 mm/s is designed and demonstrated. The designed graphene‐PVDF bimorph actuator exhibits the overall novel performance compared with many other electromechanical avtuators, and may contribute to the practical actuation applications of graphene‐based materials at a macro scale. The excellent performance of the bimorph actuator may provide a possible design for the construction of the robot. Subsequently, a fish‐like robot inspired by the dolphin swimming is designed, which is driven by the bimorph actuator upon electrical stimulus, and the fish‐like robot can swim at different frequencies, whose swimming speed is up to 5.02 mm s−1 when the voltage is 13.0 V.Herein, we demonstrate a novel electromechanical actuator which is composed of one layer of poly‐(vinylidene fluoride) (PVDF) and the other layer of flexible graphene paper, utilizing a facile process which only involves sequential filtration processing for graphene layer and drop‐coating processing for PVDF layer, respectively. PVDF is chosen as the polymer layer for several reasons: (i) PVDF as an electroactive polymer possesses excellent electrostrictive performance,22.1−6 K−1,−6 K−1.The graphene film was first fabricated by direct filtration of an aqueous suspension of reduced graphene oxide colloids followed by 400 °C annealing according to previous works.Figure2.2−1) of the β phase, as shown in Figure S1 (Supporting Information). Moreover, the graphene–PVDF bimorph actuator exhibits a good conductivity of ≈2500 S m−1. Figure I–V) curve of the graphene‐PVDF actuator. The linear line indicates that the resistance is relatively stable in the test range from 3 to 13 V. The square resistance of the graphene layer is also measured, about 58.79 Ω □−1, and this can be well in consistent with the data in the Figure Figure 2.3FigureTo investigate the actuation performance of the graphene‐PVDF bimorph actuator, a homemade setup was designed and demonstrated, as shown in D/L (displacement/length) ratio of samples with different sizes was similar. Therefore, the length–width ratio has no influence on the deflection angle of the graphene‐PVDF bimorph actuator. Subsequently, the samples with different thicknesses of PVDF layer were prepared while the sizes of the samples are uniform and the thickness of the graphene layer is 4–5 μm. The results are shown in Figure S3 (Supporting Information). The tip displacement D gets its maximum value when the thickness of the PVDF layer is 3–4 μm. So the samples in the following tests are all 4–5 μm for the graphene layer, and 3–4 μm for the PVDF layer.In order to investigate the electromechanical properties of our graphene‐PVDF bimorph actuator, the thickness and the size of the actuator were all varied and optimized. First, pieces of the bimorph actuator with the thicknesses of graphene and PVDF layers being 4–5 μm and 3–4 μm, respectively, were cut into different sizes. In Figure S2 (Supporting Information), the P =U2/R. Thus, the tip displacement variation has a mismatch with the variation of the sample temperature. Accordingly, it might be possible that the temperature change induced by the Joule effect was one of the motivations to the deflection due to the different coefficients of thermal expansion (CTE) of the two layers.When applied the direct current, as shown in Figure To further investigate the influence of the temperature change on the deflection, we extracted the temperature data from the infrared camera, and made the tip displacement of the cantilever beam as a function of the temperature. As a contrast, we also carried out a study on the deflection in which the graphene‐PVDF bimorph actuator was heated in an oven. As shown in Figure −1 under 17.0 V, which is larger than the tensile strength of traditional engineering polymer materials.To further evaluate the actuation performance of the graphene‐PVDF bimorph actuator, the electric‐induced stress of the actuator was investigated, and the results were depicted in Figure 2.4FigureThe real‐time displacement and temperature variation of the graphene‐PVDF bimorph actuator with the cycled voltage on and off were simultaneously monitored. When applied the square wave voltage 0–13.0 V), the graphene‐PVDF bimorph actuators could be triggered, and exhibited rapid and reversible swing motions, also shown in Video S1 (Supporting Information). The tip displacement variation and the temperature variation under different frequencies  were studied. .0 V, theThe frequency response and the cycle life are two significant indexes for evaluating the performance of actuators. Figure 2.5Figure−1, shown in Figure The graphene‐PVDF bimorph actuator with the ultra large displacement and fast response to the low electric voltage could provide a basis for the various robotic device applications. Herein, a fish‐like robot was designed to imitate fish swimming in petroleum ether. The fish‐like robot consists of an expandable polystyrene body and a tail which is made of the graphene‐PVDF actuator to offer the propulsion. As shown in 3−1). In addition to the conventional thermal‐induced mechanism (the different CTEs of two layers), other mechanisms including the good converse piezoelectric effect and electrostrictive performance of PVDF, also play a significant role in the fast and enhanced actuation. Interestingly, the actuator could exhibit fast and reversible swing motions without any downgrade performance due to the super mechanical properties of graphene. The actuation could response up to 14 Hz while the performance keeps unchanged with even high cycling times (over 3600 times). Finally, based on the graphene‐PVDF bimorph actuator, a fish‐like robot was built, and it could swim at the speed of 5.02 mm s−1. Note that better performance is expected with further material and device structure optimization. These results may have some important implications to design micro or light devices based on graphene for applications in various areas such as for sensors, microrobotics, switches, artificial muscle, and so on.In summary, the electric‐driven bimorph actuator comprised of one layer of graphene and another layer of PVDF was fabricated. The actuator could bend to the graphene layer side with a maximum deflection of about 14.0 mm within 0.262 s, it also could generate large stress  should be addressed to the authors.SupplementaryClick here for additional data file.SupplementaryClick here for additional data file.SupplementaryClick here for additional data file.


Herein, free-standing nitrogen-doped graphene aerogel has been fabricated via hydrothermal reaction as the potential anode material for sodium ion batteries. The three dimensional porous network structure of the graphene aerogel provides sufficient interstitial space for sodium ion accommodation, allowing fast and reversible ion intercalation/de-intercalation. The nitrogen doping could introduce defects on the graphene sheets, making the feasible transport of large-sized sodium ion. Benefiting from the effective structure and nitrogen doping, the obtained material demonstrates high reversible capacities, good cycling performance (287.9 mA h g Sodium ion batteries have been expected as the most competitive alternative due to their abundance recourse in the earth crust, low price, and similar chemical properties to lithium ion batteries6. One great challenge in achieving stable cyclability and rate capability for sodium ion batteries is making sure the reversible insertion/extraction of sodium ions, which have larger ionic radius than that of lithium ions7. Therefore, it is vital to fabricate a promising electrode material with large surface area to provide more active reaction sites and contact area for electrode materials and electrolyte, high electrical conductivity to ensure fast electron transport, as well as high porosity to access freely sodiation/de-sodiation and shorten the diffusion distance for sodium ions.Although lithium ion batteries have been regarded as the most competitive choice for high power sources and electric vehicles because of the high energy density, the limited lithium source driven researcher to explore the substitutes for lithium ion batteries8. To date, many carbonaceous material with different structures have been investigated in the electrochemical performance as anode materials for sodium ion batteries, such as carbon fibers10, nanowires11, carbon nanospheres12, reduced graphene oxide15, and porous carbon composites16. Among these materials, graphene is the most attractive anode material for sodium ion batteries due to its extraordinary electric conductivity, high surface area, and remarkable mechanical flexibility. Notably, three dimensional (3D) structured graphene with open channels allows free and fast sodium ion intercalation/de-intercalation. Furthermore, 3D graphene network acted as free-standing anode material can eliminate the loss of electrical contact between the electrode material and current collector, ensuring good electron transport.Carbonaceous materials, the common anode materials for lithium ion batteries, are considered as the attractive anode candidates for sodium ion batteries because of their good electrical conductivity, environmental friendly, low cost, and stable chemical and physical properties17. Firstly, nitrogen doping is believed to increase the electric conductivity by lowering the semiconducting gap19. Secondly, the nitrogen doping sites could attract a large number of positive ions due to the higher electronegativity around the doping area20, therefore, increase the specific capacity of graphene. Thirdly, nitrogen doping can introduce defects on the graphene sheets22. Based on the first-principle’s calculation, the defects can facilitate lithium ion diffusion from the vacancy and go through the graphene sheets due to the lower diffusion barrier around defect sites21. These appealing merits driven the study of nitrogen doped graphene as an anode material in the field of sodium ion batteries.In order to improve the specific capacity and energy density, chemical doping, especially nitrogen doping, has attracted great interests in the enhancement of the electrochemical properties of graphene−1 at a high current density of 5 A g−1 and even maintained a capacity of 287.9 mA h g−1 over 200 cycles at a current density of 100 mA g−1. The superior electrochemical performance makes the N-doped graphene aerogel material have a promising prospect in practical applications.With these motivations, nitrogen-doped graphene (N-doped graphene) aerogel was successfully synthesized via a facile hydrothermal method followed by an annealing treatment using ammonium bicarbonate as nitrogen source. Porous structure with heteroatom doping improves the interface interaction and provides efficient diffusion channels for sodium ions and electrons. The obtained material delivered a reversible capacity of 151.9 mA h g−1. After a typical hydrothermal reaction of the obtained GO aqueous solution, the reduced graphene oxide sheets assembled to form a black cylindrical hydrogel, which was then freeze-dried to form a 3D porous graphene aerogel. Finally, nitrogen doping in graphene aerogel was conducted by an annealing treatment using ammonium bicarbonate as the nitrogen source. The obtained 3D N-doped graphene aerogel is light and porous, with a low density of 0.034 g cm−3 and a good mechanical strength . Figure 2 adsorption-desorption curve presents a typical type-IV isotherm and H2 hysteresis loop with a BJH pore distribution ranged from 2.0 to 10.0 nm, which further confirms the mesoporous texture  . As shown in Fig. ure Fig. . The spe−1) Fig. .Figure 224. The graphene powder shows a broad diffraction peak owning to the stacking of graphene nanosheets. By contrast, the N-doped graphene aerogel exhibits a sharp diffraction peak with high intensity, which may be related to the fine changes of morphology on the surface25. Figure −1 and 1587 cm−1 can be observed, which correspond to D band and G band, respectively. The D band is resulted from the defects or structural disorder and G band is accordance with the E2g mode of sp2 hybridized carbon atoms26. The intensity ratio of the D to G band (ID/IG) for N-doped graphene aerogel is 1.42, which is higher than that of pristine graphene (1.40) and graphene powder (1.36). This suggests more defects were introduced on the graphene aerogel sheets after nitrogen doping. In addition, the 2D, 2D’ and the combination mode D + D’ are shown in this spectrum of N-doped graphene aerogel, indicating the existence of both monolayer and multilayers of graphene nanosheets27.X-Ray diffraction (XRD) patterns of graphene powder, graphene aerogel, and N-doped graphene aerogel are shown in Fig. 29. The C 1s peak of N-doped graphene aerogel can be fitted into three components at 284.4, 285.6 and 288.3 eV  was applied to analyze the element distribution and chemical composition on the surface layer of the N-doped graphene aerogel. Figure  eV Fig. , which a eV Fig. 31.−1. The initial capacity of N-doped graphene aerogel is 1013.8 mA h g−1. This high value in capacity is attributed to the electrolyte reductive decomposition, reactions between the oxygen-containing functional groups on the graphene sheets and sodium ions, and the formation of solid electrolyte interphase (SEI) layer35. The electrode of N-doped graphene aerogel delivered an average reversible capacity of 260.3, 242.9, 215.9, 191.1, and 151.9 mA h g−1 at the current densities of 1, 2, 3, 4, and 5 A g−1, respectively. It can be observed that there is a steady decrease in capacity from 0.1 to 2 A g−1. When the current density came back to 0.1 A g−1, the average capacity recovered to 268.3 mA h g−1, indicating a good reversibility of the composite. In comparison, the pristine graphene aerogel presents an inferior rate performance, delivering an average of 196.1, 145.5, 102.5, 73.1, and 53.7 mA h g−1 at the current density of 1, 2, 3, 4, and 5 A g−1, respectively. Figure st, 11th, 21st, 31st, 41st, and 51st cycles at respective current density, which correspond to Fig. 37.The behaviors of sodium ion intercalation/de-intercalation were investigated by a serial of electrochemical tests and shown in Fig. −1. The N-doped graphene aerogel electrode exhibits an excellent cycling stability over 200 cycles. The capacity underwent a decrease in the first three cycles and became stable from the 4th cycle, which remained a value of 287.9 mA h g−1 after 200 cycles with about 98.6% Coulombic efficiency, corresponding to 90.6% of that at the 4th cycle. In terms of the graphene aerogel sample, there is an obvious decaying in capacity during cycling. The specific capacity is 209.2 mA h g−1 at the 100th cycle with about 93.4% Coulombic efficiency, which is 71.6% of that at the 4th cycle. The cyclabilities of graphene aerogel and N-doped graphene aerogel were further evaluated a high current density of 5 A g−1 for 100 cycles, as shown in Fig. −1 at the 100th cycle.Figure The superior electrochemical performance of N-doped graphene aerogel can be attributed to the following essential features. First, the obtained 3D porous framework of N-doped graphene aerogel can provide sufficient interstitial space and more electrochemical active sites for sodium ion reaction and storage, increase the surface area for the contact between active material of electrode and electrolyte, as well as shorten the diffusion distance for sodium ions. Second, the porous structure can accommodate volume change during the sodiation/de-sodiation processes, thus maintain the structural integrity of the electrode material. Third, the robust mechanical flexibility originated from free-standing structure guaranteed an improved cyclability even at high current densities. Forth, the defects introduced by nitrogen doping make the feasible transport of large-sized sodium ion between graphene sheets and also increase the storage sites for sodium ion.−1 at a high current density of 5 A g−1 and even maintained a capacity of 287.9 mA h g−1 after 200 cycles at a current density of 100 mA g−1. The superb results demonstrate that the effective 3D framework of N-doped graphene aerogel can provide high porosity with good mechanism properties to tolerate the volume change during charging/discharging processes, increase reaction active sites for sodium ions, and facile sodium ion diffusion. The enhanced electrochemical performance can also be attributed to the nitrogen-doping introduced defects, which is beneficial to the diffusion of large-sized sodium ion during the intercalation/de-intercalation processes. This work proves that the free-standing and binder-free 3D N-doped graphene aerogel is a promising candidate anode material for sodium ion batteries with high energy storage.In summary, 3D free-standing nitrogen-doped graphene aerogel was synthesized by hydrothermal reaction and annealing treatment. The obtained materials exhibited good sodium storage performance, delivering a reversible capacity of 151.9 mA h g4HCO3), potassium permanganate (KMnO4), sodium nitrate (NaNO3), hydrogen peroxide (H2O2), and sulfuric acid (H2SO4) were analytical grade reagents received from Tianjin Chemical Reagent Technology Co., Ltd. All the chemicals were used without further purification.Graphite powder was purchased from Sinopharm Chemical Reagent Co., Ltd. Ammonium bicarbonate  graphene hydrogel was prepared through a hydrothermal process. In a typical experiment, 0.5 g of the obtained GO was dispersed in 100 mL of distilled water under ultrasonication for 4 h and subsequently treated via a hydrothermal reaction at 150 °C for 20 h to form a graphene hydrogel. The hydrogel was freeze-dried to obtain pristine graphene aerogel. To obtain the nitrogen-doped (N-doped) graphene aerogel, the pristine graphene aerogel was loaded in an alumina boat, which was placed in a larger, covered alumina boat containing excess amount of ammonium bicarbonate (6.0 g) outside of the inner alumina boat. Then the alumina boats were transferred to a quartz tube furnace under vacuum and annealed at 300 °C for 2 h. To study the effect of graphene structure on the electrochemical performance of sodium ion batteries, graphene powder without 3D structure was also prepared as a reference from the graphene oxide through a thermal reduction at 800 °C in N2 atmosphere with a heating rate of 10 °C min−1. The conductivity of N-doped aerogel measured by Four-Point Probe Meter at ambient temperature with a value of 2.4 × 10−2 S m−1, which is larger than that of graphene aerogel (2.9 × 10−3 S m−1).Graphene oxide (GO) was synthesized via a modified Hummers method−2 in the electrode. The electrochemical tests were carried out with CR2032 coin type cells. The cells were constructed with sodium foil as the anode, the prepared active material as the cathode, glass microfiber as the separator, and 1 M NaClO4 in a mixture of ethylene carbonate (EC) and propylene carbonate (PC) (1:1 by volume) as the electrolyte (about 4 drops). The whole assembly process was carried out in an argon-filled glove box. The charge-discharge cycling was performed within the voltage range of 0.01–3 V vs. Na+/Na on a battery test instrument  at ambient temperature. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements of the electrodes were carried out on an electrochemical workstation (CHI660E). The cyclic voltammograms were obtained over the potential range from 0.01 to 3.0 V at varous scan rate from 0.1 to 5 mV s−1. The EIS was conducted by applying a dc potential equal to open circuit voltage over the frequency range from 100 kHz to 0.01 Hz with an amplitude of 5 mV.The as-obtained pristine and N-doped graphene aerogel were pressed under a pressure of 20 MPa and used as the working electrodes without any conductive agent or binder. The average weight of the active material is about 0.60 g cmθ = 10° to 90°. Raman spectra were recorded on a LabRAM HR Evolution with the laser excitation of 532 nm. X-ray photoelectron spectroscopy (XPS) experiments were conducted on an ESCALAB 250Xi X-ray photoelectron spectrometer. The electrical conductivities were measured using SZT-2A Four-Point Probe Meter at ambient temperature. Brunauer−Emmett−Teller (BET) measurement was carried out on a Quantachrome NOVA 1000e instrument by N2 physisorption at 77 K. Macropores distribution was analyzed on AutoPore IV 9500 instrument (Micromeritics).The morphologies and microstructures of the resulting materials were characterized by transmission electron microscope  and field-emission scanning electron microscope . X-ray diffraction analysis were performed on a PANalytica X’PERT PRO with Cu Kα (λ = 1.541 Å) over the range from 2Supplementary Information


Studies combining immune checkpoint inhibitors with external beam radiation have shown a therapeutic advantage over each modality alone. The purpose of these works is to evaluate the potential of targeted delivery of high LET radiation to the tumor microenvironment via an immune checkpoint inhibitor.111In-DTPA-anti-PD-L1-BC, an 111In-antibody conjugate targeted to PD-L1, was evaluated in an immunocompetent mouse model of breast cancer. 225Ac-DOTA-anti-PD-L1-BC was evaluated by both macroscale (ex vivo biodistribution) and microscale (alpha-camera images at a protein concentration determined by the 111In data.The impact of protein concentration on the distribution of 111In-DTPA-anti-PD-L1-BC at 1, 3, and 10 mg/kg highlighted the impact of protein concentration on the distribution of the labeled antibody, particularly in the blood, spleen, thymus, and tumor. Alpha-camera images for the microscale distribution of 225Ac-DOTA-anti-PD-L1-BC showed a uniform distribution in the liver while highly non-uniform distributions were obtained in the thymus, spleen, kidney, and tumor. At an antibody dose of 3 mg/kg, the liver was dose-limiting with an absorbed dose of 738 mGy/kBq; based upon blood activity concentration measurements, the marrow absorbed dose was 29 mGy/kBq.The evaluation of 225Ac-DOTA-anti-PD-L1-BC is capable of delivering high LET radiation to PD-L1 tumors. The use of a surrogate SPECT agent, 111In-DTPA-anti-PD-L1-BC, is beneficial in optimizing the dose delivered to the tumor sites. Furthermore, an accounting of the microscale distribution of the antibody in preclinical studies was essential to the proper interpretation of organ absorbed doses and their likely relation to biologic effect.These studies demonstrate that  The recent successes of novel immunomodulatory agents have brought immunotherapy up to the forefront as a possible treatment against various types of cancers –4. This A number of investigators have demonstrated the potential advantages of combined immune checkpoint inhibition therapy and external beam radiotherapy –11. RadiWe previously reported on the feasibility of modifying an anti-PD-L1 antibody to deliver an imaging radionuclide in an immune-intact mouse model . This wo111In]InCl3 was purchased from MDS Nordion . 225Ac was produced from a 229Th source as described in -trans-cyclohexane-1,2-diamine-N,N′,N′,N″,N″-pentaacetic acid (SCN-CHX-A″-DTPA) using previously described standard methods yielding DTPA-anti-PD-L1 [111In]InCl3 (37-74 MBq) was added to an acid washed 1.5 mL eppendorf tube containing 0.25 mL of 0.2 M HCl and 0.03 mL of 3 M NH4OAc, pH = 7. After a minute, 0.2 mg of DTPA-anti-PD-L1-BC Ab was added to the mixture. The mixture was allowed to set at room temperature for 45–60 min and then transferred to an Amicon Ultra 10K centrifugal filter device. Phosphate-buffered saline (PBS) was added and the device was centrifuged for 15 min at 3000 rpm to remove free [111In]InCl3 (1×). Radiochemical purity of >98% was determined by radio TLC, and the protein concentration was determined by Nanodrop .The anti-PD-L1-BC Ab was conjugated to ti-PD-L1 , 24. Bri225Ac-labeled anti-PD-L1-BC Ab conjugate was prepared using the high-efficiency one-step method described in PCT/US2010/042885. For the one-step method, p-SCN-Bn-DOTA was conjugated to the anti-PD-L1-BC Ab overnight and the resulting conjugate, DOTA-anti-PD-L1-BC, was purified prior to radiolabeling. DOTA-anti-PD-L1-BC (0.5 mg) was then radiolabeled with 225Ac (23 MBq) in 100 μL of 3 M sodium acetate at 37 °C for 90 min. The resulting radiolabeling conjugate 225Ac-DOTA-anti-PD-L1-BC was purified using a 10 DG desalting column  prepped with PBS containing 1% bovine serum albumin (BSA) followed by a PBS wash. The radiolabeled conjugate was eluted with PBS and collected in 0.5 mL fractions. TLC determined radiochemical purity, and the protein concentration was determined by Nanodrop .The neu-N mice [l-glutamine + 1% non-essential amino acids (NEAA) + 1% sodium pyruvate + 0.2% insulin + 0.02% gentamycin. Cells were cultured for a maximum of 4 weeks before thawing fresh, early passage cells.The NT2.5 cell line was established from spontaneous mammary tumors in female u-N mice , 26. Dr.neu-N) female mice, 4 to 7 weeks old, purchased from The Jackson Laboratory . All animal studies were approved by the Animal Care and Use Committee of the Johns Hopkins University, School of Medicine.Animal studies were performed using FVB/N-Tg(MMTVneu)202Mul/J (neu-N mice (n = 3–5/time point) were injected subcutaneously (s.c.) with NT2.5 cells (1 × 106) in the right flank. Following a growth period of 4 weeks, the tumor-bearing mice were injected intravenously (i.v.) with 111In-DTPA-anti-PD-L1-BC (370 kBq) at the following Ab protein concentrations: 1, 3, and 10 mg/kg as well as with 225Ac-DOTA-anti-PD-L1-BC (15 kBq) at 3 mg/kg. At 1, 6, 24, 72, and 144 h post-injection (p.i.), the mice were sacrificed. The blood, heart, lungs, liver, spleen, kidneys, stomach (with content), intestine (with content), bone, thymus, muscle, tumor, and brown adipose tissue (BAT) were harvested, weighed, and measured in a gamma well counter  using the 400 to 480 keV energy window for 213Bi (440.6 keV and yield 26.1%). The percent-injected activity per gram (%IA/g) was calculated by comparison to a weighed, diluted standard.Biodistribution experiments were conducted as previously described with minor modifications , 27, 28.225Ac-DOTA-anti-PD-L1-BC within the normal tissues and tumors. neu-N mice (n = 1/time point) were injected s.c. with NT2.5 cells (1 × 106) in the right flank. Following a growth period of 4 weeks, the tumor-bearing mice were injected i.v. with 225Ac-DOTA-anti-PD-L1-BC (67 kBq). The mice were sacrificed at 1, 6, 24, and 72 h, and the organs  were immediately removed, embedded in optimal cutting temperature (OCT) compound and frozen (−78.5 °C). Consecutive, 8-μm-thick cryostat sections of each tissue were obtained for alpha-camera imaging, hematoxylin and eosin (H&E) staining, and immunohistochemistry. Immunohistochemistry was performed for CD8 . Exposure times for alpha-camera imaging were in the range of 20 to 24 h. Alpha-camera images were analyzed using the software, ImageJ 1.49 g .The alpha-camera is an ex vivo digital autoradiography imaging technique dedicated to detecting emitted alpha-particles . The alp225Ac-DOTA-anti-PD-L1-BC biodistribution data. The radioactivity concentration vs time curves were fitted using the software SAAM II  and integrated from zero to infinity to calculate the time-integrated activity per unit mass. If the data could not be fitted, the integral was obtained as the sum of a numerical integration over the measured time period and an analytically integrated exponential function based on an exponential extrapolation beyond the last measure time point that used the log-linear slope of the last two time points as the exponential clearance rate. The mean absorbed dose Normal tissue and tumor mean absorbed doses were calculated using the Ã is the time-integrated activity, 225Ac, 221Fr, 217At, 213Bi, and 213Po, and for 213Bi, 225Ac leads to the release of free 213Bi, which concentrates in the kidneys [213Bi was added to the 225Ac-absorbed dose. The radioactivity in kidneys was measured using a gamma well counter. Counts detected over a 1-min interval were recorded for 4.5 h. The measurements were fitted with a double exponential function from which the activity per unit mass (Bq/g) of free 213Bi (obtained as the time-zero intercept) and 225Ac-anti-PD-L1-BC within the kidneys at the time of sacrifice  could be determined.where fraction . For 225J/(Bq s) . Only th kidneys , 32. Acc111In-DTPA-anti-PD-L1-BC 1, 3, and 10 mg/kg biodistribution data. These data were used to calculate the TIA for three different radionuclides that are candidates for alpha-particle emitter therapy: 225Ac, 212Pb, and 211At with half-lives of 10 days, 10.6 h, and 7.2 h, respectively.To assess the impact of protein amount administered on the optimal alpha-particle emitter choice, the time-integrated activity (TIA) for the tumor, blood, spleen, liver, kidneys, and thymus were calculated using the neu-N mice (n = 5 mice/group) were injected i.v. with 225Ac-DOTA-anti-PD-L1-BC (3 mg/kg) at the following doses: 15, 22, 30, 37, and 44 kBq. The dose range was based on previously performed MTD studies with 111In-DTPA-7.16.4 as well as organ and blood clearance rates of 111In-DTPA-anti-PD-L1-BC in comparison to 111In-DTPA-7.16.4 (data not shown) [Healthy non-tumor-bearing t shown) . The mict test and two-way and one-way ANOVAs. p values were considered significant if p ≤ 0.05.Statistical analysis was performed using the software, GraphPad . Groups were compared using multiple 111In-DTPA-anti-PD-L1-BC conjugate was radiolabeled in 45–60 min at room temperature at a specific activity of 11.8 MBq/nmol with >95% radiochemical purity following purification. The 225Ac-DOTA-anti-PD-L1-BC conjugate was radiolabeled in 90 min at 37 °C at a specific activity of 4.0 ± 0.7 MBq/nmol with >95% radiochemical purity following purification.The 111In-DTPA-anti-PD-L1-BC (approximately 370 kBq) at the following protein doses: 1 mg/kg (20 μg Ab), 3 mg/kg (60 μg Ab), and 10 mg/kg (200 μg Ab); the pharmacokinetics of 225Ac-DOTA-anti-PD-L1-BC (15 kBq on 3 mg/kg) were also examined  by a rapid  phase. A lower fraction of the 225Ac-DOTA conjugate is cleared rapidly , and correspondingly, a larger component (37%) clears with a 19-h half-life. The difference in blood kinetics is consistent with the PK differences of the DOTA- compared to the DTPA-conjugate seen in the liver, kidneys, and tumor  calculations  with activities ranging between 15 and 44 kBq. All the mice were sacrificed after a 100-day monitoring period except one, which was sacrificed on day 98. Over the 100-day period, the whole-body weight of the mice decreased in a dose-dependent manner with greater weight loss at the larger administered activities . Administered activity-dependent decreases in organ weights were also observed for the spleen, kidneys, liver, and thymus. Significant decreases occurred in the spleen at the 44-kBq dose compared to the 22-kBq dose (p ≤ 0.001), as well as in the liver at the 37-kBq dose and 44-kBq dose as compared to the 15-kBq dose (p ≤ 0.01). A 20 to 40% reduction in kidney mass occurred at 22 to 30 kBq. Relative to the 15-kBq dose, significant decrease were seen at the 30 (p ≤ 0.007), 37 (p ≤ 0.005), and 44 kBq (p ≤ 0.0001) dose. In addition, a significant decrease (p ≤ 0.006) was seen at 44 kBq relative to the 22-kBq dose. Mice reaching the 100-day endpoint had blood chemistries within the normal range . The ALT was over 1000 IU/L with the normal range being 17–77 IU/L. Pathology showed significant degenerative and proliferative changes in the liver and kidney, as well as hematopoietic neoplasia in this mouse.The single mouse (44 kBq) that was sacrificed at 98 days displayed signs of pain, particularly labored breathing and a hunched back. Upon necropsy, the mouse was found to have a visually enlarged thymus and spleen, fluid appeared to have accumulated in the chest cavity, and the liver was pitted. The blood chemistries of this mouse all fell within the normal range, except the ALP and ALT. The ALP (526 IU/L) was again elevated outside the normal range and was significantly higher compared to the other 44-kBq-dosed mice , significant liver toxicity was noted, including a significant reduction in liver mass and weight loss. In this case, the macroscopic absorbed dose calculation is consistent with the observed MTD. However, the activity distribution in the spleen and thymus was highly non-uniform; correspondingly, only the highest administered activity led to a significant reduction in spleen weight, and the thymus seemed to be insensitive to administered activity. The threshold for renal toxicity occurs at 18 to 23 Gy which corresponds to 130 to 170 kBq administered activity. As is evident from EMS. 8, renal toxicity as indicated by mass reduction occurs at far lower administered activities. This again highlights the importance of dosimetry calculations that account for the microscopic localization of alpha-particle emitters. In the case of kidneys, 63% of the absorbed dose is due to free l cortex . It shoul cortex . Preclinl cortex . Given t225Ac-DOTA-anti-PD-L1-BC, successfully targeted a PD-L1-positive tumor for delivery of 225Ac. However, the low absorbed dose and highly non-uniform distribution in the tumor supports the use of this agent to supplement anti-PD-L1 therapy through the recruitment of immune cells to the tumor microenvironment.Targeted alpha-particle emitting radionuclides are extremely potent over a short range, making it a valuable treatment for treating single cells and small metastatic cell clusters. The development of PD-L1-targeted high LET agents has the potential to eradicate small metastatic sites and theoretically has an immunostimulatory effect in larger PD-L1-positive tumor sites. However, these agents also target PD-L1-positive immune cells potentially limiting their use as a therapeutic agent. Both imaging and therapy using radiolabeled antibody-based checkpoint inhibition therapy will be influenced by binding to PD-L1-positive sites in normal tissues. Such normal organ uptake may be overcome to some extent by optimizing the protein amount of antibody administered for therapy, helping to protect normal tissues and potentially preserve immune cells by saturating non-tumor PD-L1 sites. An accounting of the microscale distribution of the antibody in preclinical studies is essential to the proper interpretation of organ absorbed doses and their likely relation to biologic effect. The agent developed here, The distinction between an imaging agent used to evaluate target expression for patient selection and therapeutic response monitoring and a surrogate agent used for treatment planning is important. For the latter, the surrogate-imaging agent that best matches the pharmacokinetics of the therapeutic agent is required. Alternatively, differences in pharmacokinetics must be modeled to derive the kinetics of the therapeutic agent. In the former, a low-molecular-weight imaging agent that rapidly images PD-L1 expression in tumor sites with quick clearance is appropriate. Such an agent was recently reported and its biodistribution investigated in immunodeficient NOD-SCID (NSG) mice with xenografted tumors .


The 3D lamellar graphene structures were formed due to the synergistic effect of the tremendous heat induced gasification as well as huge volume expansion. The 3D lamellar graphene/BaFe12O19 composites bearing 30 wt % graphene present the reflection loss peak at −27.23 dB as well as the frequency bandwidth at 2.28 GHz (< −10 dB). The 3D lamellar graphene structures could consume the incident waves through multiple reflection and scattering within the layered structures, prolonging the propagation path of electromagnetic waves in the absorbers.The synthesis of 3D lamellar graphene/BaFe Electromagnetic wave absorbing materials have attracted much attention in commercial and military applications and it is significant to produce microwave absorbing materials with excellent absorption properties ,2. High 12O19 is widely used as magnetic substrate because of its high coercivity, excellent magnetization, good magnetocrystalline anisotropy, easy preparation with low cost, and adjustable properties [12O19. Nevertheless, how to obtain ultra-light and economic graphene/BaFe12O19 composite has become the essential issue in the preparation process of the composite material. The free-standing three-dimensional (3D) graphene synthesized by self-assembled method with the characteristics of broad frequency bandwidth, ultrahigh compressibility and adjustable electrical conductivity , could boperties ,8,9,10. operties  ensures 12O19 composite was prepared by self-propagating combustion, triggered by the exothermic oxidation-reduction reaction between citric acid and nitrate. The high temperature generated by self-propagating combustion could vaporize the oxygen-containing functional group of graphite and promote the formation of BaFe12O19 crystal. Therefore, graphite sheets that can take advantage of the energy are largely expanded into large amounts of lamellar graphenes due to the sudden gasification and stupendous volume expansion effect. The two-step process of preparing stabilized 3D lamellar graphene and embedding BaFe12O19 between the graphite layers to synthesize the composite material is completed at one time, which lead to simple operation procedure. In this paper, the self-propagating combustion triggered synthesis process of 3D lamellar graphene/BaFe12O19 composites has been studied, which has not been reported before.Here, we report a potential use of the self-propagating combustion  process 12O19 with high permeability and coercivity can easily widen absorption bandwidth and further expand reflection loss as well as remedying the tremendous gap between low permeability and high complex permittivity. Such superiorities of self-propagating combustion with short reaction time; little pollution, high temperature and high energy triggered by low temperature and low energy; the capability of chemical exothermic maintenance by itself; and high quality of purity of the product attract much attention [The 3D independent graphene in this composite has a wide frequency band and high dielectric constant characteristic. Meanwhile, BaFettention ,15.12O19 composite is presented in 4 in order to activate the graphite layers. Second, 3D lamellar graphene/BaFe12O19 composite was prepared by self-propagating combustion using activated graphite sheets and citric acid compound with Fe(NO3)3 and Ba(NO3)3 as precursor at 350 °C. The formation of 3D lamellar graphene structures from graphite mainly based on two effects occurred in the self-propagating combustion reaction process. The self-propagating combustion that was triggered at lower temperature can produce tremendous heat to continue the reaction and form the crystal structure. The temperature during the reaction increased to about 1500 °C. Thus, the high temperature and tremendous heat can gasify the functional groups on the graphite layers. The instantaneous gas flow could easily expand the graphite layers into multilayered graphene. Furthermore, for the second aspect, the self-propagating combustion reaction also has volume expansion effect. The precursor firstly infiltrate into the graphite layers  was activated by concentrated acid for the later reaction. First, 1 g NFG was mixed with 4 g concentrated sulfhuric acid, 2 g concentrated nitric acid and 0.8 g KMnO12O19 composite was in situ prepared by self-propagating combustion method using the activated graphite sheets and citric acid mixed with Fe(NO3)3 and Ba(NO3)3 as precursor. The mass ratio of Fe(NO3)3, Ba(NO3)3 and citric acid is 10:1:(6–15). The mass fraction of activated graphite sheets are various from 10 to 40 wt %. The ingredients were first dissolved into distilled water and then ammonium hydroxide was added to adjust pH = 7. The obtained colloidal sol was continuously heated and stirred at 350 °C to evaporate water and give rise to the self-propagating combustion process. After the combustion reaction, 3D lamellar graphene/BaFe12O19 composite was prepared. The sample powders were collected and cleaned for further test and application.The 3D lamellar graphene/BaFe2 F30, FEI: Hillsboro, OR, USA), field emission scanning electron microscope , X-ray diffraction spectrometer  and the Raman spectrometer  are used for qualitative analyses on the morphology, structural characteristics and component composition of all samples. The as-obtained samples that were used for the characterization of electromagnetic wave absorbing properties were prepared by mixing 10 wt % 3D lamellar graphene/BaFe12O19 composite with 90 wt % molten paraffin, then made into a doughnut-shaped sample . The complex permittivity  and permeability  components as the function of frequency of a sample are measured using a MS4644A vector network analyzer .High resolution transmission electron microscope , and the others are rectangular-like shape. The graphene sheets interlinked BaFe12O19 particles for increasing the dielectric loss in the composite. The 3D structure of lamellar graphene/BaFe12O19 composite is beneficial to the pass through of electromagnetic wave in different directions. 12O19 and 3D lamellar graphene/BaFe12O19 composite. The BaFe12O19 peaks labeled with crystal indices in the two curves are coincident. The spectrum of 3D lamellar graphene/BaFe12O19 composite shows the graphene peak at around 18°, proving the formation of graphene and the graphite peak at around 26°. Compared with the graphite peak in the upper curve, the peak intensity of graphite is far lower in that of lamellar graphene/BaFe12O19 composite, indicating that there is only a little residual graphite after the self-propagating combustion process. The BaFe12O19 spectrum has sharp peaks showing the good crystallinity. 12O19 composite. The spectrum has two obvious peaks centered at 1324.7 and 1593.2 cm−1, namely D and G modes of graphene. The D peak at 1324.7 cm−1 stems from a symmetry-lowering effect owing to the defects of graphene sheets. The G peak at 1593.2 cm−1 indicates the graphite crystallinity of carbon material. The ratio of ID to IG is used to characterize the structure integrity of carbon materials. 3D lamellar graphene/BaFe12O19 composite shows both the characteristic peak of BaFe12O19 (labeled in the image) and graphene. The presence of 2D peak indicates the existence of graphene. Therefore, from above characterization and analysis, the graphene/BaFe12O19 composite have a 3D lamellar structure and the BaFe12O19 particles were embedded inside the graphene sheets after the self-propagating combustion process.ε′, ε″) and permeability  curves of 3D lamellar graphene/BaFe12O19 composites (with different graphene mass fraction) vs. frequency are shown in ε′) and permeability (μ′) represent the storage ability of electromagnetic energy, whereas the imaginary permittivity (ε″) and imaginary permeability (μ″) are connected with the energy dissipation and magnetic loss, respectively [ε′) decreases slightly with frequency increasing, which is also observed by other researchers [12O19, graphene and paraffin wax plays an important role in the formation of the grain boundaries. At low frequencies, the grain boundaries are more effective than the conducting grains. Owing to the high resistance of the grain boundaries, the hopping electrons will be stacked and produce polarization at these areas. The electronic conduction is high at low frequencies due to the polarization. However, the electron exchange between Fe3+ and Fe2+ ions cannot follow the fast alternating field, which decreases the probability of electrons reaching the grain boundaries and the interfacial polarization [ε′) and dielectric loss (ε″) of 3D lamellar graphene/BaFe12O19 composites enhance with the graphene mass fraction increasing. It is easy to understand that the interlinked graphene sheets can form conducting network to increase the conductivity. With the mass fraction of graphene increasing, the conductivity of the composite improves. Besides, the lamellar graphene/BaFe12O19/paraffin wax structure has a better dielectric polarization and relaxation effects. When the conductive phase is distributed in the insulating matrix to form composite materials, the free charge gathering will exist in the insulation/conductor interface due to the difference in the two phase conductive performance. The interlinked graphene conductive networks embedded with BaFe12O19 particles improved the dielectric polarization properties. In μ′ and μ″ in some lines, respectively, those obvious peaks for μ′ and μ″ can be ascribed to a resonance phenomenon, which is also shown in inZ is the normalized input impedance at free space and material interface, rε = ε′− jε" is the complex permittivity, rμ = μʹ − jμ" is the complex permeability of absorbers, f is the frequency of the microwave in free space, d is the thickness of the absorber, and c is the velocity of light in free space. The impedance matching condition is given by inZ = 1 to represent the perfect absorption properties. The surface reflectivity of an absorber was presented as a function of six parameters, ε′, ε″, μ′, μ″, f and d [ε′, ε″, μ′, μ″, f and d (see 12O19 composites with 30 wt % graphene presents the reflection loss peak at −27.23 dB as well as the frequency bandwidth at 2.28 GHz (<−10 dB). For contrast, under the same matching thickness (dm = 2.0 mm), the absorbing peaks of 20 wt % graphene sample presents a slight decrease in absorbing peak and absorbing bandwidth, which is −22.83 dB and 2.04 GHz, respectively. However, when the mass fraction of graphene is up to 40 wt %, the reflection loss and the frequency bandwidth are only 11.18 dB and 1.61 GHz, respectively. Here, a crucial weight value at 30 wt % appears. Based on the former analysis, the dielectric loss tangent of the composite with 40 wt % graphene is larger than that of 20 wt % and 30 wt %. The possible reason for the poor electromagnetic wave absorbing properties of 40 wt % might be the poor matching degree of dielectric loss and magnetic loss, the electromagnetic wave absorbing property of pure EG without BaFe12O19 was also tested. It can be seen from that the reflection loss peak is only about −5 dB. The high dielectric loss and the poor reflection loss further prove the assumption. Overall, the electromagnetic wave absorbing properties improved with the increasing of graphene mass fraction before 30 wt % and recede after that. The composite with 30 wt % graphene presents the best performance. 12O19 composites at various thicknesses in the frequency range of 2–18 GHz with 30 wt % graphene. This indicates that the microwave absorbing ability of the lamellar graphene/BaFe12O19 composite at different frequencies can be adjusted by controlling the thickness of the absorbents [12O19 composite. The good electromagnetic wave absorbing properties of 3D lamellar graphene/BaFe12O19 composite may be explained by the following several reasons. First, the layered structures with high density graphene sheets formed conductive networks leading to more physical contacts between conductive graphene sheets, therefore it increases the resonance circuit density, which is consistent with the good electrical conductivity and large dielectric loss tangent. The graphene possess excellent electrical conductivity. The conducting networks would interact and attenuate the electromagnetic radiation in the absorbers effectively. Second, the polarization relaxation of defects or π-electron and interfacial polarization between graphene and BaFe12O19 exist. The 3D lamellar graphene structures can consume the incident waves through multiple reflection and scattering inside the layered structures, prolonging the propagation path of electromagnetic waves in the absorbers. The multiple reflections of electromagnetic wave lead to the larger losses of electromagnetic energy. Furthermore, the intertwined layer structures spontaneously and intensely response to the broadband incident wave, presenting as tremendous resistance–inductance–capacitance coupled circuits. The interaction of electromagnetic waves with dielectric materials intensified the molecular motions such as ionic conduction, dipolar polarization relaxation, etc., leading to energy dissipation in the form of heat through molecular friction and dielectric loss and the highly conductive networks would also consume the electromagnetic wave as resistance heat.The complex permittivity  in the frequency range 2–18 GHz. The 3D lamellar graphene nanostructures could consume the incident waves through multiple reflection and scattering inside the layer structures, prolonging the propagation path of electromagnetic waves in the absorbers. The multiple reflections of electromagnetic wave lead to the larger losses of electromagnetic energy.The 3D lamellar graphene/BaFe


Idiopathic pulmonary fibrosis (IPF) is a rare lung disease of unknown origin leading rapidly to death. This paper addresses the issue of whether sputum induction is a suitable tool to study respiratory tract inflammation and potential biomarkers in IPF compared to COPD, a fibrosing airway wall disease.In a cross-sectional analysis, 15 IPF patients, 32 COPD and 30 healthy subjects underwent sputum induction. Total sputum cell counts and the amount of TGF- β, IGF-1, IGF-2, IGFBP-1, IGFBP-2, IGFBP-3, IL-8, IL-13, MMP-7, MMP-9, YKL-40, TNF-α and KL-6 in sputum supernatant were analysed. We also profiled gene expression of cells in the induced sputum for TGF-β, MMP-7, YKL-40, IGFBP-2, IL-6, IL-8 and TNF-α.IPF patients, like COPD, had increased sputum absolute number of neutrophils, eosinophils, macrophages and epithelial cells compared to HS. IPF sputum supernatants had increased concentrations of IGFBP-2, IL-8, TGF-β, MMP-7, MMP-9 and KL-6  when compared to healthy subjects where COPD had higher IL-6 and TNF-α levels than IPF (p<0.05 and p<0.05 respectively) and HS (p<0.0001 and p<0.001 respectively) and higher IL-8 and MMP-9 than HS (p<0.0001 and p<0.001 respectively). Conversely to IL-6 and TNF-α, MMP-7 was increased in IPF compared to COPD (p<0.05). The KL-6 and MMP-7 protein levels in sputum were inversely correlated with total lung capacity  in IPF patients (r = -0.73 and r = -0.53 respectively). Sputum gene expression analysis identified a significant increase for IGFBP-2, IL-6, IL-8 and MMP-7 in IPF compared to HS  and for IGFBP-2, YKL-40, IL-6, IL-8 and MMP-7 compared to COPD . Furthermore, gene expression of TGF-β was increased in IPF compared to COPD (p<0.001) but not to HS.Our data show clear increase in expression and production of IGFBP-2, IL-8 and MMP-7 in sputum from patients with IPF that may contribute to the disease. Idiopathic pulmonary fibrosis (IPF) is a rare lung disease of unknown origin leading rapidly to death . The diaMany biomarkers have already been studied both in serum and BAL from ILDs and in particular in IPF where inflammation seems to take part of the disease  in additThe aim of our study was to evaluate the potential of measuring biomarkers of the fibrosing process in sputum from patients with IPF. As comparators we have recruited a group of COPD, recognized to be an airway disease featuring fibrosis of the airway wall at the periphery of the lung .We analysed the induced sputum of patients with IPF n = 15) in comparison to healthy subjects (n = 30) and COPD (n = 32). The diagnosis of IPF was made according to the international recommendations of the ATS 5 in comp and heal2014/302).The protocol was approved by the ethics committee of CHU Liège, and all subjects gave written consent before their enrolment  or isotonic (NaCl 0.9%) saline according to the FEV1 value (> or < than 65% predicted). Saline was combined with additional salbutamol delivered by an ultrasonic nebulizer  with an output set at 0.9 ml/min. Each subject inhaled the aerosol for three consecutive periods of 5 min for a total of 15 min. For safety reasons, FEV1 was monitored throughout the induction and it was stopped if FEV1 fell by more than 20% from baseline. The whole sputum was collected in a plastic container, weighed, and homogenized by adding three volumes of phosphate-buffered saline (PBS), vortexed for 30 s, and centrifuged at 800g for 10 min at 4°C. Supernatant was separated from cell pellet and stored at − 80°C. The cells were resuspended in a solution containing 5mM dithiothreitol without CaWe analysed several biomarkers assumed to be critical growth factors or chemokines in the induced sputum. The concentration of IL-6, IL-13, TNF-α, MMP-7, YKL-40 were assessed by ELISA multiplex using Fluorokine® Multianalyte Profiling Kits  according to the manufacturer’s instructions. The detection limit for this assays were 7-25-7-39-61 pg/ml respectively The concentration of the other proteins were measured separately by ELISA: TGF- β, MMP-9, IL-8, IGF-1, IGFBP-1, IGFBP-2 and IGFBP-3 ; IGF-2 ; KL-6 (Lumipulse G KL-6 Fujirebio Europe). The detection limits for these kits were 7-25-25-32-30-125-130-450pg/ml and 100 U/ml respectively.PCR was used to profile gene expression of cells in the induced sputum for TGF–β, MMP-7, YKL-40, IGFBP-2, IL-6, IL-8 and TNF-α in a subgroup of patients . mRNA expression was measured in total sputum cells by Taqman reverse transcription quantitative polymerase chain reaction (RT-qPCR). RNA extraction, and RT-qPCR were performed according to description of da Silva et al . The hou® qPCR Assays provide by IDT  were used for IGFBP-2, MMP-7, TNF-α, TGF-β1 and YKL-40. We only analysed samples with more than 50% of viability with less than 30% squamous cells. We chose a cut-off of 20 CT for the 18S and excluded samples in which more than 20 CT was needed to pick up 18S.Primers and probes for 18S rRNA, IL-6 and IL-8 were designed by Gielen and al. . The seqLung function tests were performed in our routine respiratory laboratory at CHU Liège. All spirometric tests performed for this study were measured using the pneumotachograph JaegerMasterlab system . The expiratory volume in one second (FEV) and forced vital capacity (FVC) were measured in accordance with the recommendations of the European Respiratory Society (ERS). The resDemographic and functional data were expressed as mean ± standard deviation (SD). Induced sputum cellularity was expressed as median (minimum-maximum) because of a not normal distribution. When the data showed normal distribution, they were compared with a one-way ANOVA, followed by Tukey-Kramer’s post-hoc testing. When the data did not show a normal distribution, they were compared by Kruskall-Wallis followed by Mann-Whitney testing. Correlations between variables were assessed using Spearman’s rank correlation test. A p<0.05 was considered as significant.The demographic, functional and treatment characteristics of the subjects are given in Induced sputum (IS) from IPF patients showed an increased cellular concentration in comparison to healthy subjects . There wSeveral biomarkers were measured in sputum supernatant . There wGene expression analysis identified a significant increase for IGFBP-2, IL-6, IL-8 and MMP-7 in IPF compared to HS  and for IGFBP-2, YKL-40, IL-6, IL-8 and MMP-7 compared to COPD . Table 5)Table 5).In IPF, there was an inverse correlation between sputum supernatant protein levels of MMP-7 and KL-6 and % predicted TLC  . DiffusiOur groups were not fully matched with respect to age, sex and gender and smoking status. Therefore we performed a specific analysis in the HS group in which we didn’t find any correlation between biomarkers and age, gender and smoking status (data not shown).Here we report for the first time concomitant measurement of gene expression and protein levels of growth factors and matrix metalloproteinases in sputum from patients with IPF. We confirmed that TGF- β, IL-8, KL-6 and MMP-7, known to be biomarkers in IPF based on serum and BAL analysis, are also significantly higher in induced sputum from IPF patients. Furthermore IGFBP-2, recently identified as a new protein involved in IPF , was alsSputum cell count of patients with IPF revealed an intense inflammatory pattern with raised total cell counts including granulocytes, macrophages and epithelial cells confirming previous finding of Beeh et al. . This inTGF-β, widely known as a key actor of fibrosis and known to be elevated in BAL of IPF patients , was incOur study also confirmed the importance of MMP-7, a matrix metalloproteinase specifically found to be raised both at gene and protein level in sputum from IPF compared to COPD and HS. While MMP-9 was increased in both IPF and COPD, it is remarkable that the raised expression and protein amount of MMP-7 was limited to patients with IPF compared to HS. Our results are in keeping with those of Zuo et al. who reported a greater MMP-7 gene expression in lung tissues of IPF patients  and withWe found a significant and specific increase in KL-6 in sputum supernatant from IPF. As with MMP-7 there was also a negative correlation between TLC (%pred) and sputum protein level of KL-6. KL-6 is well known as a biomarker in pulmonary fibrosis , 31 and We have recently shown that serum IGFBP-2 was raised in IPF . Here weGene expression of IL-6 in IPF was increased compared to both healthy subjects and COPD though the protein level remained comparable to that measured in healthy subjects. In IPF IL-6 is pro-mitogenic for fibroblasts due to the sustained activation of MAP Kinases in contrast to what is seen normal fibroblast . In ordeAs aforementioned, one of the potential limitation of the study is the cross sectional design that precludes any interpretation of the predictive values of these biomarkers in the follow-up of the patients. A further limitation is that we were unable to assess the expression and the levels of the growth factors in patients receiving anti-fibrotic therapy. Finally the lack of perfect matching between our groups regarding age, gender and tobacco may be seen as a potential confounding factor. However we have to say that it is extremely difficult to recruit a large number of healthy subjects above the age of 65 yrs. To address this issue of potential confounding factors we have assessed the relationship between age, gender and tobacco smoking and protein and gene expression of biomarkers in the group of healthy subjects and we did not find any significant correlation.Our data show clear increase in expression and production of several growth factors and matrix metalloproteinases and chemokine in sputum from patients with IPF. Whether sputum analysis may become a suitable and less invasive tool than BAL to predict and monitor evolution of the disease and the response to treatment should be investigated in prospective longitudinal trials.


The nature of police work often necessitates use of Individual Light Armour Vests (ILAVs) for officer protection. Previous research has demonstrated various biomechanical and physical performance impacts of ILAVs, however, little knowledge exists on the individual officer’s perceptions of ILAV. The aim of this study was to investigate officers’ perceptions of the impacts of three different ILAVs and normal station wear whilst performing police occupational tasks.A prospective, within subjects, repeated measures design was employed in which 11 serving police officers wore each of three different types of body armour  and normal station wear for a full day while performing tasks including a simulated victim drag, a patrol vehicle exit and a marksmanship shoot. Ratings of Perceived Exertion (RPE) and a Visual Analogue Scale  were used to examine officer perceptions of each ILAV. Finally, officers were asked to indicate areas of both discomfort and comfort of each ILAV on a mannequin chart.Officers perceived less effort was required for the victim drag whilst wearing ILAV B (RPE = 3.6/10) when compared to ILAV A, ILAV C and even station wear . A positive impact on performance was perceived for ILAV B (VAS = + 0.26) when performing a patrol vehicle exit and sprint task but not for the other two ILAVs . Officers perceived a positive impact of ILAV B (VAS = + 2.7) and station wear (VAS = + 1.4) and a negative impact of ILAVs A and C  on marksmanship. Despite all armour types being criticized for discomfort, ILAV B received lower ratings of discomfort overall, and some positive comments regarding both comfort and performance.Officers perceived ILAV B to have positive effects on task performance. It was also rated more comfortable than the other two, possibly due to a longer torso design which shifted load from the shoulders to the hips and pelvis. Officer perceptions of comfort and effects on occupational performance should be considered when designing and procuring armour systems. Although ILAVs may be similar, perceived impacts may vary between officers. Policing duties may intermittently involve periods of running, jumping, crawling and engaging in combat without warning , 2. NumeMore recently, lighter Individual Light Armour Vests (ILAV) weighing between 2.7–3.8 kg have been implemented to reduce officer fatalities from stabbing, blunt trauma and small calibre bullets .The importance of acceptance of additional loads by the tactical personnel who must carry them was evident in a study by Ramstrand et al. , who exaGiven the importance of acceptance by the wearer before implementation of ILAVs, the opinions of individuals required to wear the equipment should be sought during the ILAV design or procurement phases, if user engagement with the proposed ILAVs is to be achieved. Therefore, the aim of this study was to investigate officers’ perceptions of the comparative impacts of three different types of ILAV and normal station wear when they were worn while performing occupational tasks associated with policing duties.A prospective, within-subjects, repeated measures design was employed, using a counterbalanced randomization procedure to determine the order of types of ILAV and normal station wear worn by each participating officer. Each officer served as their own control and wore each of three types of ILAV for one full day, and normal station wear for one full day. On each day, all measures were taken at the same time of day while the officers wore the ILAV or standard station wear assigned for that particular day. The counterbalanced randomization procedure controlled for any potential activity learning effects and other factors (eg ambient conditions) that might have varied across the 4 days of data collection.Data collection for the study was conducted at an Australian State police college in 2016. Eleven research volunteer officers who were all qualified and serving members of the Australian State Police Force, served as participants for this study. The officer’s characteristics can be seen in Table To improve the translation of this research across the general State police force population, equal numbers of female and male officers were initially recruited, with two participants per gender sized as each of small, medium and large, with respect to the standard sizes used by the ILAV suppliers. This process and diversification allowed for the comparison of the perceived impacts of three ILAV and normal station wear in relation to both gender and body size. All of the 12 initially-recruited officers were provided an initial briefing regarding the program and, if they expressed willingness to participate , they were invited to provide written informed consent for participation. One recruited female officer was unable to commence the research due to medical concerns which were identified at this stage and so the final sample was reduced to 11 officer participants. All participants formally consented to participation and the study was approved by the Bond University Human Research Ethics Committee (protocol number 15803).The three different types of ILAV  were all weighed  prior to provision. Each type of ILAV was then fitted with standard equipment worn by each officer as part of their normal duties. This equipment was individualised and varied slightly due to each officer’s daily taskings and preferences. This equipment carried as part of normal duties also made up the fourth condition; normal station wear (N). On the days of testing, officers wore their allocated load configuration for the duration of the day. Officers were randomly allocated to one of four initial conditions  using a lot draw on the first day of data capture which employed a counterbalanced approach. Following the first day of data collection, each participant progressed to the next ILAV to be trialled, in the specified sequence, which progressed from ILAV A to ILAV B to ILAV C to normal station wear to ILAV A.To minimise any diurnal variations a standardised program was followed on each day. Noting that this program of data capture was part of a larger project, with other measures also captured, the aspects of the daily program relevant to this study are shown in Table The Rating of Perceived Exertion  is a measure of a person’s perception of the rate of effort required for a given task. While the original scale was rated between a score of 6 (no exertion) and 20  , the modThe 10 m victim drag scenario utilized a mannequin fitted with a ballistic vest (80 kg). Officers were required to lift the shoulders of the mannequin off the ground and, moving backward, drag the mannequin 6 m, complete a 90-degree right hand turn through a doorway, and continue to drag the mannequin another 4 m to the end of the track. This configuration was designed to mimic retrieving a victim from the centre of a road and then dragging them back and behind cover. The distances officers covered for the victim drag task were measured using a digital mini-measuring wheel . Officers were allowed an initial practice run at their estimated 80% of maximum capacity, to familiarize themselves with the scenario and as a warm up.The Visual Analogue Scale (VAS) is a commonly used tool to quantify perceptions of a particular type of experience . On comprapid patrol vehicle exit task, a police patrol vehicle  was parked so that the driver’s side of the vehicle opened onto a track. Officers were seated in the driver’s seat of the vehicle without their seatbelt on and with both hands on the steering wheel. A researcher gave a verbal command ‘go’ to start the scenario whilst simultaneously breaking the beam of the electronic timing system light gate . The officer exited the driver’s side of the vehicle and ran to the rear of the vehicle through two opposing timing gates placed 5 m away, as measured using a digital mini-measuring wheel   with a Glock model 22 pistol, firing 26 rounds in total, with marksmanship scored over three separate sequences. These three sequences were: Point/proximity shooting (9 rounds); Immediate distance / kneeling (5 rounds); and Transition drills / reloading (12 rounds). Each sequence assessed a single or related multiple skill set which was deemed a mandatory and necessary skill set for the operational policing environment. As soon as officers completed their marksmanship scenarios they were asked to rate on the VAS how the ILAV or normal station wear they were wearing impacted on their shooting ability. For the duration of the marksmanship task, the volunteer officers were under the direction and authority of the State police force Range Safety Officers.The participating officers were instructed not to remove their assigned ILAV, for the duration of each day (e.g. during lunch or short breaks), and following completion of activities on each day, the officers were requested to indicate on a manikin figure Fig.  any areaAll recorded data except for data relating to the participants’ subjective evaluations of ILAV were entered into a spreadsheet in SPSS version 23 (IBM 2015) and were then cleaned for analysis. Initial descriptive analyses were conducted to provide counts, means, standard deviations and ranges for the included variables, as relevant depending on levels of measurement. These descriptive statistics were derived for each ILAV type and for the normal station wear.Following these descriptive analyses, a multivariate repeated measures analysis of variance (ANOVA) was conducted to examine the relative impacts of the different ILAV types and normal station wear, with post hoc pairwise comparisons using a Bonferroni adjustment. Finally, subjective evaluations documented by the participants regarding comfort of the ILAV and normal station wear were aggregated onto a single body chart for each type of ILAV assessed, in order to provide an overview for each ILAV type of the evaluations from all participants. Comments on each body chart were numbered according to the identification number assigned to the participant who made the comment, so that multiple comments by the same participant could be identified and so that where comments were more frequent from particular participants, commonalities in those participants’ characteristics  that might have affected their evaluations could be considered.p < .04 in all instances).An overview of the measured weights of each ILAV type is provided in Table p = .048). Average RPE scores attributed to the victim drag task by officers when wearing each type of ILAV are seen in Table Subjectively, ILAV type significantly affected required effort in the victim drag, as assessed by participants using the RPE scale .p = .026). The average impact officers perceived each ILAV condition to have on their performance in the range shoot, as measured by the VAS, was positive in both ILAV B and normal station wear and negative in ILAV A and ILAV C (Table The repeated measures ANOVA indicated that ILAV condition significantly affected officer self-assessments using the VAS of ILAV impacts on task performance (marksmanship) during the range shoot  and normal station wear on subjective measures of performance and comfort whilst police officers performed occupational tasks associated with their normal policing duties. Despite numerous previous investigations reporting the effects of wearing armour on performance and mobility, there has been minimal focus on the opinion of the individual who wears the armour and no known studies comparing multiple types of ILAV.There were significant differences in the weights of the three types of body armour used in this study, with ILAV A being the heaviest and ILAV C being the lightest. Also of note, body armour weight increased as the body weight, height and chest circumference of the officer increased, since the size of the body armour required to fit them increased and so also its weight.The results from this study suggest that overall, ILAV B appeared to be the most preferred by officers when compared to other ILAV configurations, across all three tasks. For both the 10 m victim drag and marksmanship, ILAV B received significantly better ratings that the other ILAV configurations in relation to its impact on task performance. For the 10 m victim drag task the least amount of effort required to complete the task across all ILAV conditions was reported by participants to be associated with ILAV B. Likewise, ILAV B received positive  ratings regarding impacts on marksmanship performance. Interestingly, the quickest times of the Victim drag and the best score on the marksmanship task were whilst wearing ILAV B, so officer perceptions matched objective measures of performance on those tasks.In contrast to previous research , 16, 17 When data from each configuration’s subjective evaluation sheet was collated, it was apparent that the major areas of discomfort for all ILAV were the chest, shoulders and hips. This is in agreement with previously published research which found that, apart from the foot, the low back and hips were the areas of least comfort for carriers of load , 19, 20.The outcomes of this study demonstrate that the subjective feedback of officers regarding both comfort and performance are important to consider for the issuing of ILAV and that their perceptions regarding performance are accurate. For example, there was a notable preference for one of the three types of ILAV and whilst wearing this preferred ILAV, the subjective perceptions of performance were in most cases reflected in the objective measures of performance in the tasks.The future development and large-scale implementation of ILAVs should ensure that the user’s feedback and opinion is sought to ensure that first and foremost they are going to be worn, and that perceived comfort and performance impacts are considered. Seeking the opinion and acceptance of the officers who will be required to wear the equipment is vital to ensure a balance between user acceptance and equipment requirements are obtained, and given the costs associated with the procurement of new equipment for law enforcement, studies on subjective acceptance should be performed before any procurement decisions are made.There are some limitations to this study which need to be acknowledged. The results from this study are only applicable to the 3 variants which were utilised in this study and therefore may not be representative of all options available to law enforcement officers. The opinions expressed by the sample of officers in this study may also not be representative of the entire police force and a larger scale study may therefore be warranted.The results from this study suggest that participants perceived that wearing ILAV B assisted them in performing several key occupational tasks . The ILAV B also had fewer negative comments with respect to comfort and fit throughout the testing period and these findings may at least in part have been due to the longer torso design of ILAV B, shifting load of the ILAV from shoulders and chest to the hips and pelvis. Conversely, the other ILAVs were found to be more uncomfortable on the neck and shoulders, and detrimental to occupational task performance, when this was assessed both subjectively and also objectively. Nevertheless, ILAV B did cause more pressure on hips and pelvis and obstructed deployment of belt-mounted tactical equipment to some degree, according to participants, and this may be of operational concern. Overall, the results from this study suggest that feedback from wearers is important when considering the implementation of ILAV and involving personnel in this way may form an important part of organisational acceptance of new ILAV.