We show that all these intriguing phenomena can be interpreted based on the unique band structures of graphene quantum dots and graphene as well as resonant quantum tunneling.The occurrence of zero effective mass of electrons at the vicinity of the Dirac point is expected to create new paradigms for scientific research and technological applications, but the related discoveries are rather limited. Here, we demonstrate that a simple architecture composed of graphene quantum dots sandwiched by graphene layers can exhibit several intriguing features, including the Dirac point induced ultralow-threshold laser, giant peak-to-valley ratio (PVR) with ultra-narrow spectra of negative differential resistance and quantum oscillations of current as well as light emission intensity. In particular, the threshold of only 12.4 nA cm In graphene, electrons possess zero effective mass in proximity to the Dirac point, an unusual feature that could trigger the development of novel photonic devices. Here, the authors combine graphene quantum dots with two graphene layers and observe laser action with ultralow threshold. A single layer graphene possesses linear energy momentum dispersion relation at the edges of hexagonal Brillouin zone, which leads the electrons and holes to behave as a massless Dirac Fermion with exceptionally high mobility6. It has triggered the experimental realization of several fundamental physical phenomena and offered a fascinating material for electronic and optoelectronic applications1. Over last few years, several applications have been demonstrated using various intriguing properties of graphene including ultrahigh carrier mobility, excellent tensile strength and high transparency10. Notably, linear dispersion relation makes the graphene Fermi energy (EF) extremely sensitive to its neighboring perturbations11. Thus, it has become a challenging issue to achieve the exceptionally high mobility of graphene film in a real device. Up until now, practical applications of massless Fermions around the Dirac point are not yet realized. On the other hand, graphene quantum dots (GQDs) reveal a new promise of bandgap opening in mesoscopic grapheme13. Several studies suggest that the energy band in GQDs can be highly influenced by the functional groups attached on the GQD matrices as well as the quantum confinement of the carriers14, which makes explicit explanation of the bandgap and related luminescence difficult.Graphene has been studied extensively during last decade owing to its unique physical, chemical and mechanical propertiesHerein, with a simple all-graphene-based architecture consisting of GQDs sandwiched between two graphene layers, we demonstrate the Dirac point induced ultralow-threshold laser action due to the rapid formation of population inversion by fast transport of massless charge carriers. In addition, we discover a giant peak-to-valley ratio (PVR) and ultra-narrow spectra of negative differential resistance (NDR). Furthermore, we observe quantum oscillations in both conductance and light emission spectra. These intriguing features may pave the way to the development of new optoelectronic and nanoelectronic devices.2 substrate  to the bottom-graphene (GrB) as shown in Fig. −1 in the band structure of GQDs20. This result is consistent with the X-ray photoelectron spectroscopy data as shown in Supplementary Fig. EF of the subsequent graphene changes monotonically. The EF close to a certain energy state of GQDs thus causes a resonant tunneling of electrons24as shown in Fig. 25. Notably, the tunneling electrons from the graphene electrode trapped in the energy levels of GQDs will block the tunneling of electrons with energy below the Fermi level of the graphene layer. We therefore can observe a very pronounced peak and valley characteristics. In addition, the injected charge carriers in GQDs can be used to generate electroluminescence and laser action as shown below. These distinct characteristics are very different from the graphene/hexagonal boron nitride (h-BN)/graphene heterostructure as reported previously26. Because h-BN is a wide bandgap material, it hardly carries any energy states in between its conduction and valance bands. Hence, the tunneling can occur from the density of states between the chemical potential of the two graphene electrodes, which leads to a quite different behavior. The average PVR of the current in the lower bias region is found to be >20. The two adjacent current peaks are found to be separated by ~0.30 V, which corresponds to an energy separation of ~ 135 cm−1 based on the estimated EF shift due to the change of external bias27 -grown graphene on SiOI–V curve in Fig. 2 in the curve, the tunneling current is dramatically enhanced owing to the existence of a very low effective mass of electrons4 in yellow region, as shown in the inset of Fig. 3, while the Fermi energy just crosses the neutrality point but still belongs to its vicinity, as the green region shown in the inset of Fig. 29. This abnormal behavior of current has not been realized in late studies on graphene tunnel transistors30. The observed nature of the measured current can be distinguished from previously reported conduction in graphene4 and graphene-based tunneling junctions26 with the help of existing theoretical models31. The energy states of graphene under scanning tunneling microscope (STM) measurement forms a quasi-planar junction with STM tip due to the existence of a large amount of neighboring bulky atoms  around the Dirac point4 as shown in Fig. EF of graphene approaches the Dirac point, as discussed above, the tunneling current arising from massless Dirac carriers is enhanced abruptly, which causes a sudden appearance of massive number of electrons in the conduction band of GQDs as illustrated in Fig. 35. With the application of an external bias, when the Fermi energy approaches the Dirac point of single-layer graphene (SLG), electrons with ultrahigh speed will be injected into the GQDs and result in a robust enhancement of the emitted photons in the GQD matrix. The emitted light from the GQDs suffers multiple scatterings in the GQD matrix while travelling through it, which provides an excellent platform for optical feedback in the active material producing multiple coherent feedback loops. Because the optical feedback matrix in our device is randomly distributed, the observed lasing behavior is therefore named as random action. Under a particular external bias, when the Fermi level of SLG is close to the Dirac point, the resonance tunneling occurs, and the injected electrons can only populate a particular set of vibrational energies. Thus, even though the emitted lights from the GQD matrix produce a broad spectrum, only the emission corresponding to the energy of resonant tunneling states close to the Dirac point can overcome the energy loss due to the massive number of injected electrons. Consequently, the appearance of only three lasing peaks in the emission spectra under the forward bias is due to the recombination of the population inversion in the vibrational energy levels of the GQDs caused by resonant tunneling near the Dirac point and the formation of coherent loops arising from multiple scatterings. For the reverse bias, because the graphene attached to PMMA contains a different initial Fermi energy compared with the graphene on SiO2, it produces slightly different energy band diagram which is not identical to the forward bias. In this case, the tunneling current and optical feedback that cause the random laser action will be different from that of applying forward bias. The enhancement of the background emission corresponding to the higher pumping voltage can be inferred to the enhanced number of injected electrons when the Fermi level approaches resonance tunneling condition. To further consolidate the random lasing mechanism, we have measured the angular dependence of the emission spectra as shown in Fig. 38. Note that the lasing threshold voltage depends on the polarity of external bias, which is due to the difference between the zero-bias Fermi energy of the top- and bottom-graphene layers. The average output power is found to be ~1 nW cm−2 at the applied voltage above lasing threshold.The most fascinating achievement in our study is the observation of electrically pumped ultralow-threshold laser action assisted by the ultrahigh mobility of carriers  of Dirac electrons4, the conductivity is quite high, which enables to greatly reduce the power consumption. Thirdly, the formation of coherent optical feedback loops due to multiple scatterings in the GQD particles is suspended, which enables to overcome the reflection energy loss due to the absorption of substrate. Finally, unlike conventional semiconductor laser devices, which were made with a complicate structure consisting of highly resistive layers, the simple structure of our device only contains a thin layer of GQDs sandwiched by graphene, which can result in ultralow dissipation of input power.Quite interestingly, the Dirac point induced laser action shows a unique feature of ultralow-threshold injection current density. It was observed that the device lases at an applied voltage of ~6.8 V and ~4.5 V under positive and negative bias, respectively, with an injected threshold current density of ~12.4 to 18 nA cm44. With increasing radiation density, the lifetime of excited states decreases still further. For our case, in the vicinity of the Dirac point, the electrons behave as massless Fermions. Thus, when the Fermi energy is tuned to the Dirac point of graphene, the resonance energy tunneling of the Dirac electrons from graphene induces a rapid formation of population inversion in GQDs and generates stimulated emission, which in turn shortens the carrier lifetime.To further confirm the nature of the laser action, we have measured the carrier lifetime of the device under the excitation of a 375 nm pulse laser while applying different bias voltage to the device as shown in Supplementary Fig. I–V curve is observed without any indication of oscillation  as shown in Supplementary Note 2 layer as shown in Supplementary Note 2 layer in between graphene layers does not exhibit any resonant behavior. A more detailed discussion is included in Supplementary Note I-V curve is not observed due to the defect-induced change in the electronic properties of the graphene layers45.To consolidate the results as described above, we have fabricated the device in which the GQD layer was replaced by an inactive SiO48 and is very costive54. Thanks to the unique band structure of graphene integrated with semiconducting materials, all these difficulties can be easily overcome as shown in this study. It is believed that our approach can be extended to several other material systems to achieve laser action covering a wide range of spectrum. For example, using lanthanide composite nanoparticles, indeed, we are able to successfully demonstrate an infra-red laser , the PMMA was spin coated on graphene at 2,000 r.p.m. for 25 s, and annealed at 100 °C for 2 min. We then used FeClAzadirachtaindica) leaf extract was obtained by grinding the Neem leaves using a commercial grinder. It was then boiled at 80 °C for 1 h in 20 ml of ultrapure deionized (DI) water, which was then centrifuged at a relative centrifuge force (RCF) of 12,000 g for 10 min in order to remove the remaining solid residue. The collected mixture was then filtered through a 22 µm membrane to further remove the trace solid residue. The supernatant was then added in a 10 ml glass bottle and stirred and sonicated at 24 °C for 30 min. It was then hydrothermally treated at 300 °C for 8 h in an autoclave, where it produces a brown transparent suspension and black precipitate. After the solution was cooled down to room temperature, the precipitate was carefully discarded. The suspension was then further centrifuged at higher RCF of 25,000 g for 20 min. The precipitate was discarded and the suspension was collected and washed twice in 10 ml ultrapure water. Then, the supernatant was dialyzed for 3 h using a filter of cutoff 3.5 kDa and subsequently dried overnight to get pure GQDs. The yield is found to be ~25.2%, and for every 250 mg of Neem leaf extract, ~75 mg of GQDs were produced. Next, 13.5 mg of obtained GQD was mixed in 60 ml of ultrapure DI water to produce a suspension of GQD which was used to design the device. The estimated cost of the built of materials was found to be 1 USD per 1 g of pure GQD. A detailed analysis of the property of graphene and GQD is provided in the Supplementary Notes To fabricate the GQDs, 250 mg of Neem  which costs 1$ per g. The reported costs for high-quality single-layer graphene is reported to be 115$ per m2. Commercial high-quality silicon wafer is available in 2$ per inch2, which makes the estimated costs of our device ~3$ per device.A schematic diagram of device fabrication is provided in Supplementary Fig. −2. Simultaneously, we applied different bias voltage to obtain the bias voltage-dependent carrier lifetime. The emitted photon intensity was collected by a TRIAX 320 monochromator of Horiba Jobin Yuvon. The obtained lifetime data contain ±0.2 ns errors induced by TRIAX 320.The electronic characterizations of the device were employed using Keithley 2400 electrometer and standard probe system. The optical measurements were performed by iHR 550 spectrometer of Horiba Jobin Yvon. The lasing phenomena is obtained by using IHR 550 spectrometer of Horiba Jobin Yuvon and Keithley 2400 electrometer. A constant bias voltage is applied to the device using Keithley 2400 electrometer and the emission spectrum was subsequently collected by IHR 550 spectrometer and Synapse CCD detector. The carrier lifetime of a particular emission wavelength was obtained by recording the transient intensity of emitted photons corresponding to the emission under 374 nm pulsed laser of pulse width 55 ps, frequency 40 MHz, and energy density of 5 µJ mDt, Db and Dvib are the carrier density of states in top graphene, bottom graphene and the vibrational-level GQDs, respectively26. The ft and fb are the Fermi distribution function of the top and bottom graphene; ɛf = ɛf0 is the initial Fermi energy of the graphene and ɛfi is the Fermi energy of the graphene close to ‘i’th vibrational energy level; 0.0155 eV is the period of the –OH out of plane vibrational energy levels20. T represents the tunneling coefficient, which can be expressed as equation  = [Φt(d−z) + (Φb−eV)z]/d, where the work functions Φt = Φb = 4.6 eV for both of the graphene layers.The current in our device can be expressed by equation , where, The data that support the findings of this study are available from the corresponding author upon request.Supplementary Information


This study aims to use high throughput 16SrRNA gene sequencing to examine the bacterial profile of lymph node biopsy samples of patients with sarcoidosis and to further verify the association between Propionibacterium acnes (P. acnes) and sarcoidosis.A total of 36 mediastinal lymph node biopsy specimens were collected from 17 cases of sarcoidosis, 8 tuberculosis (TB group), and 11 non-infectious lung diseases (control group). The V4 region of the bacterial 16SrRNA gene in the specimens was amplified and sequenced using the high throughput sequencing platform MiSeq, and bacterial profile was established. The data analysis software QIIME and Metastats were used to compare bacterial relative abundance in the three patient groups.P < 0.01). P. acnes 16SrRNA was exclusively found in all the 17 samples of the sarcoidosis group, whereas was not detected in the TB and control groups. The relative abundance of P. acnes in the sarcoidosis group (0.16% ± 0. 11%) was significantly higher than that in the TB  and control groups . The relative abundance of P. granulosum was only 0.0022% ± 0. 0044% in the sarcoidosis group. P. granulosum 16SrRNA was not detected in the other two groups.Overall, 545 genera were identified; 38 showed significantly lower and 29 had significantly higher relative abundance in the sarcoidosis group than in the TB and control groups  contains supplementary material, which is available to authorized users. Sarcoidosis is a systemic granulomatous disease and often involves the respiratory system. The disease frequently affects middle-aged adults, in particular women aged 40–50 years. The histopathology of sarcoidosis is characterized by non-caseous necrotizing granulomas, and the clinical presentation of the disease is very diverse . The exaPrevious reports studying the association of infection and sarcoidosis mainly focus on Mycobacterium tuberculosis (MTB) and propionibacteria, and show controversial results. Eishi et al.  used reaMost of the previous studies investigated only a few bacterial species. A full bacterial profile of the tissue specimens of patients with sarcoidosis is still lacking. The current study is filling this knowledge gap. In the current study, we aim to conduct high throughput 16SrRNA gene sequencing to investigate the bacterial profile of mediastinal lymph node specimens. The 16SrRNA gene is present in the genome of bacteria, chlamydia, rickettsia, mycoplasma, spirochaeta, and actinomycetes, but absent in eukaryotic organisms, viruses, and fungus. The sequence of V4 region of the bacterial 16SrRNA gene, which varies greatly in different bacterial species, is often considered as a unique signature for a bacterial species and thus commonly used for bacterial taxonomic classification –12. The The protocol for collecting and handling patients’ biopsy specimens has been approved by the Institutional Review Board of Shanghai Pulmonary Hospital and Tongji University School of Medicine . Biopsy specimens from the mediastinal lymph node of 36 patients, who were treated in Shanghai Pulmonary Hospital between August 2014 and August 2015, were collected and analyzed. All the 36 patients, including 17 cases of sarcoidosis, 8 cases of TB, and 11 cases of control, were inpatients of Shanghai Pulmonary Hospital. The 8 patients with TB were newly diagnosed based on positive MTB in their sputum. The 11 controls included 6 cases of nonspecific lymphadenitis and 5 cases of mediastinal lymph node metastasis of lung cancer. The clinical data of the patients are displayed in Table The diagnostic criteria for sarcoidosis followed the 1999 guidelines of ATS/ERS/WASOG  and the Patients with TB were diagnosed according to the 2013 tuberculosis diagnosis and treatment guidelines recommended by the China Medical Association Tuberculosis Society . The diahttp://ccb.jhu.edu/software/FLASH/)[http://drive5.com/uchime/uchime_download.html) using the UCHIME Algorithm  [Because the sequence of V4 region of the bacterial 16SrRNA gene is a unique signature of a bacterial species, the sequence can be used to identify the specific bacterial taxonomic position . The V4 go.html)  to identgo.html) . The reshttp://drive5.com/uparse/) [http://greengenes.lbl.gov/cgi-bin/nph-index.cgi) [http://sourceforge.net/projects/rdp-classifier/) [The identified 16SrRNA sequences (the effective sequencing tags) were annotated using the Uparse software package v7.0.1001 (uparse/) . The anndex.cgi)  and the sifier/) . The seqTo estimate if the identified 16SrRNA sequences could include all the bacteria in the samples, we conducted alpha diversity analysis. The alpha diversity was analyzed using the Quantitative Insights into Microbial Ecology (QIIME) software (Version 1.7.0) . To evalhttp://drive5.com/uparse/) were used to analyze bacterial abundance. The Metastats software (http://metastats.cbcb.umd.edu/) was used to compare the difference in bacterial abundance between different groups. The Metastats software is specifically designed to compare bacterial abundance by quantitatively analyzing the 16SrRNA gene sequences [Bacterial relative abundance was determined to identify the most predominant bacterial species, which represent the bacterial profile in the samples. The Quantitative Insights into Microbial Ecology (QIIME) software (Version 1.7.0) and Uparse software package v7.0.1001  > 0 represented inter-group difference > intra-group difference; R < 0 represented inter-group difference < intra-group difference; P < 0.01 was considered statistically significant. A P value was first calculated for inter-group difference in relative abundance. The P value was then adjusted to q value using an algorithm established by Storey and Tibshirani [P and q values, Taxonomic units showing significantly different relative abundance in the three groups were identified. When both P < 0.01 and q < 0.01, the differences were considered statistically significant. The software Graphpad prism 5 was used to prepare the curves of bacterial relative abundance. The software SPSS 20.0 was used for chi-square analysis of the inter-group difference in bacterial positive rate; P < 0.01 was considered statistically significant.Intra-group comparison was performed to evaluate the differences in the bacterial profile of samples in the same patient group. Inter-group comparison was performed to estimate the difference in the bacterial profile of the sarcoidosis, control, and TB patient groups. Because bacterial profile is expected to vary considerably in different individuals, evaluation of inter- and intra-group difference may reveal the unique characteristics of bacterial profile in sarcoidosis, control, and TB patient groups. For inter-and intra-group comparison of bacterial profile, R software (version 3.1.3) was used for nonparametric multi-response permutations procedure (MRPP)  and the bshirani . Based on = 10) with sarcoidosis were at chest X-ray stage I. The percentages of specific T cell populations, including CD3, CD4, and CD8, were similar in the sarcoidosis and TB groups. So were the levels of IgG, IgA, IgM, C3, and C4  and the 16SrRNA sequence database, GreenGene database (http://greengenes.lbl.gov/cgi-bin/nph-index.cgi). The annotations of all the 8748 are presented in Additional file Sequencing data are presented in Additional file At the taxonomic genus level, the OTUs were assigned to 545 genera based on the Greengenes database . Among the 67 genera, 38 showed significantly lower relative abundance in the sarcoidosis group than in the TB and control groups  and 11 control patients . In contrast, the other 28 bacterial genera were detected in all the patients in the three groups, suggesting that these bacterial genera may not be specific for patients with sarcoidosis. The relative abundance of the Propionibacterium Genus in the sarcoidosis group was 0.16% ± 0. 11%, which was significantly higher than that in the control  and TB groups .Among the 29 bacterial genera with significantly higher relative abundance in the sarcoidosis group, The Propionibacterium Genus was found in all the 17 patients with sarcoidosis (100% positive rate) but was completely absent in all the 8 patients with TB  and control  groups, the differences was not statistically significant. The relative abundance of mycoplasma was also very low in the three groups: 0.0067% ± 0.0090% in the sarcoidosis group, 0.0026% ± 0.0034% in the control group , and 0.0020% ± 0.0023% in the TB group . The differences were not statistically significant. Neither Borrelia nor and chlamydia was detected in the samples.In addition to propionibacteria, mycobacteria , 27, 28,P = 0.0010, q = 0.0038) and TB  groups  and TB  groups  and Propionibacterium granulosum (P. granulosum). P. acnes was detected in all the 17 patients with sarcoidosis, whereas P. granulosum was detected in only 5 of the 17 patients. Both Propionibacterium species were not found in the control and TB groups. The relative abundance of P. acnes in the sarcoidosis group (0.16% ± 0. 11%) was significantly higher than that in the control  from patients with non-sarcoidosis diseases showed positive P. acnes culture . Oswald To identify potential pathogenic bacteria of sarcoidosis, we previously used quantitative PCR to quantify the copy number of 16SrRNA gene of P. acnes and P. granulosum in the lymph node specimens and found that propionibacteria existed in 80% of sarcoidosis specimens but only in 4.5% of TB specimens . To furtThe possible pathogenic mechanism of P. acnes in sarcoidosis development has been tested in animal models. Kouji Iio et al. used heat-inactivated P. acnes and Freund's complete adjuvant to induce pulmonary granuloma in mice, and found that the total number of lymphocytes and the ratio of CD4+ to CD8+ T cells in the bronchoalveolar lavage fluid of the mice with pulmonary granuloma were higher than those of the control mice . Their sCompared with quantitative PCR approach, high throughput16SrRNA gene sequencing is a more effective approach to investigate bacterial profile of biopsy specimens and identify the predominant bacterial species in the specimens. The sequencing approach also allows us to compare the diversity and relative abundance of bacteria in specimens. Although quantitative PCR approach may be sensitive, low-cost, and fast, the sequencing approach can produce data for comprehensive analyses, such as bacterial taxonomy, bacterial diversity, and the correlation of bacterial profile evolution and sarcoidosis progression. The current study first used high throughput sequencing approach to investigate the bacterial profile in lymph node specimens of patients with sarcoidosis and to identify that propionibacteria were exclusively present in the sarcoidosis specimens. The advantages of the sequencing method include high throughput, high reproducibility, and high accuracy. The limitations of the sequencing method include technically complex and requiring special instrument and software for the analysis. In addition, the roles of those bacteria with significantly higher or lower abundance in the sarcoidosis group compared with the control and TB groups in the development of sarcoidosis remain unclear. Furthermore, the control groups in the current study included lymph node specimens of patients with nonspecific lymphadenitis and of patients with mediastinal lymph node metastasis of lung cancer, which may contribute to the highly various bacterial profiles in the control group. Another limitation of the current study is that the number of tissue specimens in the current study was relatively small. We are currently collecting more samples to further investigate the dynamic evolution of bacterial profiles in the sarcoidosis lesions at different disease stages.The current study used high throughput 16SrRNA gene sequencing to demonstrate that P. acnes exclusively existed in the mediastinal lymph node specimens of patients with sarcoidosis but was absence in the specimens of patients with TB or other non-infectious lung diseases. These findings indicate that P. acnes may correlate with sarcoidosis etiology.


For future on-chip communication schemes, it is essential to integrate nanoscale materials with an ultrafast optoelectronic functionality into high-frequency circuits. The atomically thin graphene has been widely demonstrated to be suitable for photovoltaic and optoelectronic devices because of its broadband optical absorption and its high electron mobility. Moreover, the ultrafast relaxation of photogenerated charge carriers has been verified in graphene. Here, we show that dual-gated graphene junctions can be functional parts of THz-circuits. As the underlying optoelectronic process, we exploit ultrafast photo-thermoelectric currents. We describe an immediate photo-thermoelectric current of the unbiased device following a femtosecond laser excitation. For a picosecond time-scale after the optical excitation, an additional photo-thermoelectric contribution shows up, which exhibits the fingerprint of a spatially inverted temperature profile. The latter can be understood by the different time-constants and thermal coupling mechanisms of the electron and phonon baths within graphene to the substrate and the metal contacts. The interplay of the processes gives rise to ultrafast electromagnetic transients in high-frequency circuits, and it is equally important for a fundamental understanding of graphene-based ultrafast photodetectors and switches. The graphene is electrically contacted by metal strips made from Ti/Au (10 nm/250 nm), which allow to apply a bias voltage Vsd. First, two adjacent 10 nm thick Pt gates are lithographically defined on a sapphire substrate. Then, a 30 nm thick, ALD-grown (atomic layer deposition) Al2O3-layer isolates the gates from the graphene. Subsequently, CVD-grown  graphene is mechanically transferred to the sampleIsampling7Iphoto is measured with the help of a current-voltage amplifier while the sample is scanned laterally by the help of piezoelectric positioners. Iphoto at Vsd = Vg1 = Vg2 = 0V. For these experimental parameters, Iphoto shows opposite signs on both sides of the junction, as it will be discussed below.For the excitation of the graphene, we use a laser system that emits laser pulses with a 30 fs pulse duration at a repetition rate of 80 MHz in the spectral range from 900 to 1500 nm cf. . The lasIsampling across the Auston-switch samples the electromagnetic transients on the striplines as a function of the time-delay Δt between the two laser pulses, and it is directly proportional to the ultrafast photocurrents in the graphene. Hereby, the photocurrents in the graphene can be measured with a picosecond time-resolution7For measuring the ultrafast optoelectronic dynamics of the graphene-based junction, we use an on-chip THz-time domain photocurrent spectroscopy of the stripline circuits 7212223, 721222122Rtotal is measured with a current-voltage amplifier to gain insights into the electronic properties of the dual-gated graphene junction. Rtotal, when both voltages of gate1 and gate2 are varied simultaneously. We find the charge neutrality point of the graphene for negative gate voltages (Vd < 0V), which implies that it is intrinsically n-doped. Rtotal, when Vg1 and Vg2 are varied independently. We apply the following modelThe two-terminal resistance n0 is the residual charge carrier density (i.e. the minimum sheet carrier concentration), nind the gate-induced charge carrier density, n the total charge carrier density. The term Δ is defined as C* the specific capacitance εr = 6.0 the relative permittivity and d = 30 nm the thickness of the Al2O3 layer). The data in Here, Rcontact accounts for the constant resistance of the metal striplines and the ungated graphene region. Rgi represents the gate voltage dependent resistance of the two  gated graphene sections, respectively. This resistance is related to the conductivity by l = 4 μm and w = 25 μm are the length and width of the gated graphene sections, respectively. The conductivity σi(Vgi) can be tuned by the gate voltage Vgi and is calculated from Rcontact = 2.57 kΩ and mobilities of μ1 = 157 cm2V−1s−1 and μ2 = 278 cm2V−1s−1. The charge neutrality point is reached at Vd1 = −1.92 V and Vd2 = −2.77 V. The fit further reveals Δ1 = 3.20 V and Δ2 = 2.62 V. The expression VTE can be written asThe photo-thermoelectric effect910113467Ti the change in electron temperature for a segment with constant thermopower Si. We define the x-axis as in T and for constant thermopowers Sg1 and Sg2 for the two areas on top of gate1 and gate2. We note that a symmetric heat profile is introduced by the laser pulse with the given FWHM of ≈5.5 μm  from the fit of Rtotal = Rtotal in Vg1 and Vg2: for a given gate voltage Vg2 and Seebeck coefficients Sg2  for different gate voltages Vg1 and Vg2. The voltage settings are defined by the indices in t between pump and probe pulse is zero. For a longer time-delay, we observe a rising and decaying behavior of Isampling (gray area). We label the latter response as ‘decay current’. For each gate voltage setting, we fit Isampling(Δt) with a constant offset, a Lorentzian (green area), and an exponentially rising and decaying function τdecay and τriseVg2 than on Vg1 for this laser position. We further note that the peak current and the decay current can have different polarities at certain gate voltages  and the difference in the thermopowers on both sides of the graphene give rise to a thermoelectric voltage VTE = (Sg1−Sg2) ΔT, that drives a photocurrent as long as the temperature profile is present. We can further infer that the so-called photovoltaic effect plays only a negligible role. In particular, the photovoltaic effect would only depend on the difference of both Fermi levels of dual-gated graphene junctions. In other words, its sign should change along the diagonals of 44In order to explain the measured ultrafast peak and the decay currents in 1316193233343513171837394142Δt < 13.3 ps as a function of both gate voltages for three different excitation positions of the laser spot. The excitation position is varied in steps of 2 μm from an excitation position closer to gate1 (Vg1 (Vg2). In other words, the decay current predominantly depends on the voltage of the gate at which the laser is focused. The numerical model .


This review focuses on the role of the lung microbiome in idiopathic pulmonary fibrosis. Although historically considered sterile, bacterial communities have now been well documented in lungs both in healthy and pathological conditions. Studies in idiopathic pulmonary fibrosis (IPF) suggest that increased bacterial burden and/or abundance of potentially pathogenic bacteria may drive disease progression, acute exacerbations, and mortality. More recent work has highlighted the interaction between the lung microbiome and the innate immune system in IPF, strengthening the argument for the role of both host and environment interaction in disease pathogenesis. Existing published data suggesting that the lung microbiome may represent a therapeutic target, via antibiotic administration, immunization against pathogenic organisms, or treatment directed at gastroesophageal reflux. Taken altogether, published literature suggests that the lung microbiome might serve in the future as a prognostic biomarker, a therapeutic target, and/or provide an explanation for disease pathogenesis in IPF. Idiopathic pulmonary fibrosis (IPF) is a rare lung disease of unknown origin which leads rapidly to death ,2. HowevIn this review we are going to approach successively the respiratory microbiome in healthy subjects and the main alterations described in IPF microbiome, during stable disease and during exacerbations, as well as its interaction with the host response. We have performed a systematic search in PubMed by typing the words: (“Microbiota”[Mesh]) and  or “Idiopathic Pulmonary Fibrosis”[Mesh]) and (microbiome) and  or “Idiopathic Pulmonary Fibrosis”[Mesh]), and selecting those thought to be relevant. Publications dates of selected papers range from 2010 to 2017. The epithelial surfaces of the respiratory tract, previously thought to be sterile, have been shown, by using culture-independent techniques, to accommodate dynamic microbial communities. High-throughput bacterial 16s-rRNA sequencing has been described to identify bacterial DNA in 95.7% of bronchoalveolar lavage (BAL) specimens compared with conventional culture techniques, which detected bacteria in 39.1% of BAL samples . Prevotella sp.), Firmicutes (including the genera of Streptococcus sp. and Veillonella sp.) and, to a lesser extent, Proteobacteria and Actinobacteria [The bacterial communities of healthy lungs closely resemble those of the mouth , while bbacteria ,28,29.The exact composition of the lung microbiota results from three main factors. The first one is microbial immigration due to microaspiration of gastric content, direct mucosal dispersion from the oro-nasal cavities, and to the inhalation of air. The second one is the microbial elimination, which results from the mucociliary clearance, cough and immunity. Finally, the third factor is the local microbial growth environment that includes notably nutrient availability, oxygen tension, pH and temperature. As a consequence of those three factors, the lung microbiota represents a steady state between microbial influx, efflux and reproduction rates, the latest being mostly altered in case of pathological processes. In every lung disease studied to date, the lung microbiome is altered compared with that of healthy subjects .Given the sensitivity of the molecular technologies employed, an obvious concern in many studies is contamination of samples from the upper respiratory tract when sampling, providing a false representation of the true microbiome ,19. AlthBeyond studying the microbiota, a small minority of studies have focused on fungi and viruses. Recent studies have shown that commensal fungi not only affect the host immune system, but can also affect bacterial composition and have a particularly important influence during restoration of the bacterial microbiota after antibiotic treatment . Virome Even if the exact pathophysiology of IPF is still incompletely understood, the microbiome is suspected to play a role in the pathology . Indeed,The hypothesis that IPF progression is influenced by microbes is supported by the finding that immunosuppression increased the risk of death and hospitalization . AnotherHaemophilus, Streptococcus, Neisseiria and Veillonella sp. are more abundant in patients with IPF compared to controls [The microbiome of IPF patients is distinct from healthy individuals: their bacterial load is overall higher, and the genera controls . It is acontrols , as eachcontrols .Streptococcus, Neisseria and Actinobacterium sp. genera. Interestingly, bacterial DNA was not detected in five out of eight patients colonized with Pneumocystis jirovecii, suggesting this fungus may impair bacterial colonization of the airways [The first exploratory application of a culture-independent molecular technique in IPF studied the microbiome in BAL from 17 IPF patients . Using 1 airways . A small study then investigated the upper and lower respiratory tract microbiota in a heterogenous group of 18 patients with interstitial lung disease (ILD), including five with idiopathic interstitial pneumonia (IIP), six patients with pneumocystis associated pneumonia and nine healthy controls . The 16sPrevotella, Veillonella and Cronobacter sp. Moreover, the presence of a specific Streptococcus or Staphylococcus OTU  above a certain threshold was associated with a faster-progressing disease, after adjusting for age, sex, smoking status, respiratory function, six-minute-walk test and the presence of gastro-intestinal reflux [Later on, a multicenter cohort study of Correlating Outcomes with biochemical Markers to Estimate Time-progression in idiopathic pulmonary fibrosis (COMET) , retrospl reflux . Howeverp < 0.0001). Secondly, there was a significant association between patients with higher BALF bacterial load and disease progression at six months  by 10%, or death) compared with controls (p = 0.02). Furthermore, it was possible to stratify patients according to bacterial burden in order to predict mortality risk, patients with higher bacterial burden having an increased risk of mortality (hazard ratio: 4.59) compared with patients with low bacterial burden. After logistic regression analysis, the abundance of Veillonella, Neisseria, Streptococcus and Haemophilus sp. remained significantly associated with IPF. Moreover, the study found that patients carrying a minor allele at the MUC5B promoter had a lower bacterial burden, providing a mechanistic link between bacterial burden and a mutation known to be relevant in IPF. A large study published in 2014 investigated 65 well-defined IPF patients and 44 controls which included 27 healthy controls and 17 patients with moderate chronic obstructive pulmonary disease (COPD) . The firToday, it is still unclear whether changes in microbiome seen in IPF are a cause or a consequence of the disease. The PANTHER trial  has idenNlrc4, Pglyrp1, Mmp9, Defa4). Additionally, that team found two genes encoding specific antimicrobial peptides (Slpi and Camp). Several of the identified genes were linked to poor survival and disease progression. These results suggest a host response to alterations of the respiratory microbiome in IPF, suggesting that these microbial changes would possibly trigger a response associated with the damage often observed in IPF patients. As they conclude, “the bacterial communities of the lower airways may act as persistent stimuli for repetitive alveolar injury in IPF” [In a study from Molyneaux et al. , the aut in IPF” .Streptococcus sp. OTU, and that this phenomenon is correlated with poorer PFS. Staphylococcus and Prevotella sp. OTUs are also associated with poorer PFS, with decreased expression of immune response pathways genes and with overexpression of TLR-9 in PBMC. Finally, the increased presence of a specific Veillonella sp. OTU is correlated with increased CpG fibroblast responsiveness. This study demonstrates that host defense, as assessed by immune pathway gene expression, may be modulated by variations in the lower airway microbiome and that bacteria with increased abundance and decreased diversity are associated with decreased immune pathway genes expression and poorer PFS. This study also demonstrates that host-microbiome interaction may influence immune-mediated fibroblast responsiveness.Another independent study  evaluateOn the other hand, Wang et al.  have att2)/inspiratory oxygen fraction (FiO2) ratios, higher C reactive protein (CRP) levels, higher percentages of neutrophils and lower percentages of lymphocytes in BALF compared with survivors. Amongst those factors only CRP was found to be an independent predictor of survival, suggesting that infection  and/or inflammation can be one of the pathogenic mechanisms contributing to acute exacerbations [The progression of IPF is marked with exacerbations, similar to a number of chronic lung diseases. Acute exacerbations are associated with a particularly poor prognosis. Among patients with acute exacerbations, non-survivors had shorter durations of dyspnea, lower arterial oxygen tension (PaOrbations .An exacerbation is currently defined as “an acute, clinically significant deterioration of unidentifiable cause in a patient with underlying IPF” , and it Campylobacter sp. and Stenotrophomonas sp., coupled with a significant decrease in Veillonella sp., and Campylobacter sp., although best known as a gastrointestinal pathogen, was previously identified in the respiratory microbiota of individuals with severe COPD. Its presence in the respiratory microbiota is likely to arise from silent micro-aspiration of gastric contents [Another study on 20 patients with diagnosed acute exacerbations of IPF and 15 matched controls with stable IPF who underwent bronchoscopy and DNA extraction has shown that IPF patients presented an increased bacterial burden during exacerbations, up to four times higher [All of these findings open the possibility of a place for antibiotherapy in IPF patients; in particular, they provide a rationale for clinical trials of long-term antibiotherapy acting as an immunomodulator and an antibioprophylaxis to prevent acute exacerbations. In the future, an improved knowledge of the dynamic alterations of the lung microbiome might help to select appropriate, targeted and more personalized antibiotherapy in the course of the disease, in particular in IPF exacerbations. In this context, more advanced metagenomic analyses are required to elucidate the functional role of individual bacterial genera and communities in IPF progression.As recent studies demonstrated interactions between host immune response and microbial community in IPF, further studies will probably focus on the exploration of therapeutic approaches targeting modulation, not only of the lung microbial community of patients with IPF, but of specific components of the innate immune system.


KS tumors consist of latently infected endothelial cells; however, lytic phase gene products are important for KS onset. Early KS lesion progression is driven by proinflammatory cytokines supplied by immune cell infiltrates including T cells and monocytes. KSHV-infected monocytes may supply the lytic viral products and the inflammatory milieu conducive to KS tumor progression. To establish successful infection, KSHV extensively modulates the host immune system. KSHV antigens activate both innate and adaptive immune responses including KSHV-specific T cells, but lifelong infection is still established. Programmed death ligand 1 (PD-L1) is a prosurvival cell surface protein that suppresses T-cell-mediated killing. PD-L1 is variably present on various tumor cells and is a targetable marker for cancer treatment. We show that KSHV infection of human monocytes increases PD-L1 expression and transcription in a dose-dependent manner. We also saw evidence of lytic gene expression in the KSHV-infected monocytes. Intact KSHV is needed for full PD-L1 response in human monocytes. KSHV induces a general proinflammatory cytokine milieu including interleukins 1α, 1β, and 6, which have been implicated in early KS lesion progression. KSHV-mediated PD-L1 increase may represent a novel mechanism of KSHV-mediated immune modulation to allow for virus survival and eventually malignant progression.Kaposi’s sarcoma-associated herpesvirus (KSHV) is associated with the human malignancy Kaposi’s sarcoma and the lymphoproliferative disorders primary effusion lymphoma and multicentric Castleman’s disease. KSHV establishes lytic infection of monocytes  KSHV is the etiologic agent of Kaposi’s sarcoma and the lymphoproliferative disorders primary effusion lymphoma and multicentric Castleman’s disease. Programmed death ligand 1 (PD-L1) is an immunosuppressive cell surface marker that inhibits T cell activation. We report that KSHV infection of primary human monocytes upregulates PD-L1 transcription and protein expression. Analysis of the cytokine and chemokine milieu following KSHV infection of monocytes revealed that KSHV induces interleukins 1α, 1β, and 6, all of which have been implicated in KS development. Our work has identified another potential immune evasion strategy for KSHV and a potential target for immunotherapy of KSHV-derived disease. KS re–gression . Therefogression –16. T ceression –, 17–20. sion –17–, 20. Chrsion –17––23. A spion –17––, 25. In ion –17–––30. Impoon –17––––34.in vivo and in vitro , IL-1β, and IL-6 are found within the KS tumor microenvironment -like receptors, to adaptive immune mechanisms, such as downregulation of major histocompatibility complex I (MHC-I) antigen presentation and expression of immunosuppressive viral cell surface homologues . Increasde novo infection of primary monocytes with KSHV induces increased PD-L1 levels through increased PD-L1 gene transcription. We also found evidence of lytic gene expression in the KSHV-infected monocytes. UV-inactivated KSHV failed to induce similar PD-L1 increases, suggesting that infection with KSHV is driving PD-L1 increase. Infection with increasing doses of KSHV correlate with increasing PD-L1 surface expression and transcription. KSHV-infected monocytes produce a general proinflammatory response similar to the KS tumor microenvironment cytokines with enrichment of IL-1α, IL-1β, and IL-6 compared to uninfected control cells. Overall, these data suggest that KSHV infection of monocytes may promote an immune tolerant environment and a cytokine milieu potentially allowing for both viral evasion and oncogenic progression.We report that As KSHV has evolved multiple strategies for evasion of the immune response, we hypothesized that KSHV may modulate the PD-1–PD-L1 pathway. Monocytes are permissive for KSHV infection  and exprn = 14), 48 hpi (n = 9), and 72 hpi (n = 8). These data suggest that infection with KSHV increases PD-L1 transcription at early time points and that while the protein level  to assess PD-L1 transcript levels. All PD-L1 transcript levels were normalized to β-actin message. PD-L1 transcription peaks at 24 h postinfection and then tapers off at 48 and 72 h postinfection . The genin level  remains To ensure that the increase in PD-L1 message and level of expression is due to primary KSHV infection, the level of KSHV RNA present inside the infected monocytes was assessed. RNA was extracted from monocytes at 48 h after infection with either intact KSHV or UV-inactivated KSHV. The levels of viral interleukin-6 (vIL-6) were quantified via real-time PCR for message levels at 48 h postinfection . KSHV vISimilar to other herpesviruses, KSHV infection displays either a latent or lytic life cycle . We infe48–We investigated the ability of UV-inactivated KSHV virions to increase PD-L1 levels at 48 h postinfection . PD-L1 s8 genomes/well) and a high dose of KSHV (2.1 × 109 genomes/well). At both 24 and 72 h postinfection, the cells that were infected with the higher dose of virus expressed higher levels of PD-L1 on the cell surface than the cells infected with the low dose of virus , and alpha tumor necrosis factor (TNF-α) changed significantly. Raw concentrations for significantly changed cytokines are shown in PD-L1 expression can be driven by cytokine signaling pathways . FurtherInterestingly, the levels of nearly all of the 35 analytes tested were increased in response to KSHV infection in monocytes compared to mock-infected cells . MonocytIn this report, we show that KSHV infection of human primary monocytes results in an increase in PD-L1 expression. This increase was at the transcriptional level, and although transcript levels decreased over time, protein levels remain increased at least until 72 h after primary infection with KSHV. We show that at 48 h postinfection of monocytes, KSHV expresses multiple lytic transcripts and the lytic protein ORF45, suggesting establishment of an overall lytic phase of infection. Cells that were exposed to increasing amounts of virus exhibited increased KSHV vIL-6 transcription as well as increased PD-L1 transcription and protein expression. In addition to an increase in PD-L1 expression, infected cells also increased production of a variety of generally proinflammatory cytokines and chemokines. Together these data suggest that KSHV induces an immune response in cells and one of the potential mechanisms that KSHV may utilize to decrease immune responses is through upregulation of the immunomodulatory protein PD-L1.KSHV-mediated expression of PD-L1 may be an additional mechanism among many already identified for KSHV evasion of host immune responses. It is critical that KSHV avoid detection in order to maintain lifelong infection within the host. To this end, mechanisms for blockade of many major immunological pathways have already been identified including the host complement system, type I interferons, Toll-like receptors, Nod-like receptors, and cytosolic DNA sensors . For manin vitro  using the monocyte isolation kit II (Miltenyi Biotec) according to the manufacturer’s instructions. The CD14-positive monocytes were assayed for purity, and in all experiments, only a ≥85% pure monocyte population was used. The resulting monocytes were plated into six-well dishes at 5 × 10Kaposi’s sarcoma-associated herpesvirus (KSHV) was isolated from iSLK.219 cells harboring latent recombinant KSHV.219 (rKSHV.219) . iSLK.217 to 7.8 × 109 genomes/well and 10 μg/ml Polybrene in serum-free RPMI medium at 2,500 rpm for 90 min at 30°C as previously described  and PD-L1  prior to analysis on a MACSQuant VYB cytometer (Miltenyi Biotec) and FlowJo software (Tree Star). Programmed death ligand 1 (PD-L1) levels were ascertained after gating on CD14.6 monocytes, cells were resuspended in 40 microliters of a solution of 50 ml NP-40 buffer  and subsequently frozen and thawed once to complete lysis. For samples more than 5 × 106 monocytes, cells were resuspended in 2× Laemmli sample buffer and simultaneously boiled and vortexed at 1,200 rpm in a ThermoMixer (Eppendorf) until the pellet was no longer visible (10 to 20 min). Equal amounts of protein were loaded per lane, resolved by SDS-PAGE, and then transferred to a nitrocellulose membrane. The antibodies used were PD-L1 , ORF45 , and actin .Cells were harvested, washed once with PBS, and then lysed. Lysis was mediated through two separate methods depending on cell number harvested. For samples less than or equal to 5 × 10CT) values similar to those of the aforementioned primers. The forward and reverse primers for cytokines, chemokines, and other targets follow: for viral IL-6 (vIL-6), forward, 5′-CGGTTCACTGCTGGTATCT, and reverse, 5′-CAGTATCGTTGATGGCTGGT (RNA was isolated using RNeasy Micro kit (Qiagen) and reverse transcribed with SuperScript III reverse transcriptase (Invitrogen) and oligo(dT) (Invitrogen). Real-time PCR was performed on a QuantStudio 6 Flex (Applied Biosystems) with PowerUp SYBR green PCR master mix (Applied Biosystems). The PCR was carried out with 1 cycle of 50°C for 2 min and 95°C for 10 min, followed by 40 cycles of 95°C for 15 s and 60°C for 1 min. All fold activations were normalized to β-actin. The primer sequences used for β-actin and PD-L1 were as follows: for β-actin, forward, 5′-TCATGAAGTGTGACGTGGACATC, and reverse, 5′-CAGGAGGAGCAATGATCTTGATCT ; for PD-TGGCTGGT ; for opeTGGCTGGT .Supernatants were precleared and tested with a human cytokine magnetic 35-plex panel (Life Technologies) per the manufacturer’s instructions and analyzed with a MAGPIX instrument (Luminex).All calculations were conducted using the R software package version 3.3.3 “Another Canoe” (released 6 March 2017) with the specific statistical tests indicated. Code is available upon request.


It has been suggested that the research priorities of those funding and performing research in transplantation may differ from those of end service users such as patients, carers and healthcare professionals involved in day-to-day care. The Kidney Transplant Priority Setting Partnership (PSP) was established with the aim of involving all stakeholders in prioritising future research in the field.The PSP methodology is as outlined by the James Lind Alliance. An initial survey collected unanswered research questions from patients, carers and clinicians. Duplicate and out-of-scope topics were excluded and the existing literature searched to identify topics answered by current evidence. An interim prioritisation survey asked patients and professionals to score the importance of the remaining questions to create a ranked long-list. These were considered at a final consensus workshop using a modified nominal group technique to agree a final top ten.The initial survey identified 497 questions from 183 respondents, covering all aspects of transplantation from assessment through to long-term follow-up. These were grouped into 90 unanswered “indicative” questions. The interim prioritisation survey received 256 responses , resulting in a ranked list of 25 questions that were considered during the final workshop. Participants agreed a top ten priorities for future research that included optimisation of immunosuppression , prevention of sensitisation and transplanting the sensitised patient, management of antibody-mediated rejection, long-term risks to live donors, methods of organ preservation, induction of tolerance and bioengineering of organs. There was evidence that patient and carer involvement had a significant impact on shaping the final priorities.The final list of priorities relates to all stages of the transplant process, including access to transplantation, living donation, organ preservation, post-transplant care and management of the failing transplant. This list of priorities will provide an invaluable resource for researchers and funders to direct future activity. Kidney transplantation is arguably the most successful treatment for end-stage kidney failure in suitable patients, with evidence that demonstrates cost effectiveness, improved survival and improved quality of life in comparison with patients remaining on dialysis ,2. Over Despite the success of kidney transplantation there are still challenges. The limited donor pool means that access to transplantation is not universal, with a median waiting time of 1,022 days for adult patients in the United Kingdom resulting in a waiting list of around 5,600 patients at any one time . FurtherGiven these challenges, it is perhaps not surprising that the field of kidney transplantation has a very active research community. The research agenda has typically been set by individual researchers or industry, with over one third of randomised controlled trials in transplantation receiving industry funding . It has Increasing recognition of a potential mismatch between the priorities of end service users and researchers/funders has led to a drive towards involving healthcare professionals, patients and carers in projects identifying and prioritising topics for research. This approach has been championed by the James Lind Alliance in the UK, a not-for-profit organisation now a part of the National Institute for Health Research (NIHR) Evaluation, Trials and Studies Coordinating Centre (NETSCC). These “Priority Setting Partnerships” (PSPs) have been successful in a number of areas of medicine, and have led to successful funding of many of the research questions identified –14.The aims of the present study were (i) to identify unanswered research questions in the field of kidney transplantation from end service users  and (ii) to prioritise these questions according to the needs of these groups, for use in future decision making by funders and researchers.The Kidney Transplant Priority Setting Partnership followed the methodology described in detail in the James Lind Alliance (JLA) guidebook . In keepNational patient and professional organisations and charities involved in kidney transplantation were contacted about the project and invited to contribute to a steering group. This group included representation from the Centre for Evidence in Transplantation (CET), British Transplantation Society (BTS), Renal Association (RA), British Renal Society (BRS), Kidney Research UK (KRUK), the National Kidney Federation (NKF) and the British Kidney Patient Association (BKPA). The group was chaired by an experienced advisor from the JLA (LM). The steering group developed the protocol for the project and was involved in all stages of its management. It included transplant surgeons, nephrologists, transplant recipients, living donors and carers. Additional partner organisations were invited to take part in the process by involving their members in the surveys and helping to promote the process. A full list of partner organisations is included in the Supporting Information .The steering group also defined the scope of the project. This incorporated all stages of the transplant process, including access to the waiting list and pre-transplant assessment, the transplant procedure itself, post-transplant care in the short and long-term, management of the failed transplant and issues surrounding retransplantation and living-donor transplantation. Scope included both adult and paediatric patients and their carers and clinicians. In order to maintain the focus of the process, it excluded management of end-stage kidney failure other than transplantation, donor selection and management (other than living donors) and issues specific to combined organ transplants.In order to identify potential research questions, an online survey was created to collect possible questions, along with the demographic details of the respondents. The survey was open-ended, simply asking “What unanswered questions about kidney transplantation and living donation would you like to see answered by research?” with space for up to three questions to be submitted. The survey was piloted by members of partner organisations and the wording refined according to feedback. It was also made available in paper format to improve access. The paper version included the same instructions and questions with the same wording as the online version, and was made available on request. The survey was open to responses between October and December 2014, and promoted via the steering group, partner organisations and other interested individuals. Methods of dissemination included websites, blogs, social media, society/organisation e-mailings and print newsletters distribution of flyers at conferences and events and display of posters and leaflets in transplant centres. The survey was open to all transplant recipients and those on the transplant waiting list, their carers, live kidney donors and professionals involved in the care of kidney transplant recipients in the UK. As the purpose was to collect as many potential research questions as possible, multiple submissions from the same respondent were allowed.The steering group also identified two recent previous surveys from the BTS and KRUK to which respondents were asked to submit potential research questions. Questions from these surveys that fell within the scope of the PSP were also included, although demographic information were not available.The raw submissions were imported into a custom designed MySQL database. Responses were reviewed by two researchers and those that were out of scope (as defined above), or that could not be translated into an answerable research question, were identified. These questions were reviewed by the entire steering group and only excluded if all members agreed.The remaining questions were grouped into similar themes using a pre-defined taxonomy to form a set of “indicative” research questions that covered the scope of all questions submitted. These indicative questions were expressed in the PICO  format as far as possible, although many questions were broad and all four parameters were not defined. Classification and grouping was initially performed by two researchers, with the results discussed in detail by the entire steering group to agree the final indicative questions.www.transplantlibrary.com), which includes all randomised controlled trials and systematic reviews  published in the field of solid organ transplantation between 1970 and present, identified from searches of MEDLINE the Cochrane Library and hand searches of conference proceedings. The purpose of the literature review was to identify any of the questions that were considered adequately answered by the existing literature. In order for a question to be considered answered, an existing up-to-date systematic review with a clear conclusion had to be identified. Questions with no available review, outdated reviews or with an existing review that expressed uncertainty in its conclusions  were considered unanswered. Questions considered answered were discussed in detail by the steering group prior to exclusion from the remainder of the process. A full description of the strategy and search terms used to identify existing reviews is provided in the Supporting Information (Two experienced systematic reviewers reviewed the transplant literature for each of the remaining indicative uncertainties in order to assess the extent of the existing evidence. The primary sources for this review were the Cochrane Library and the Transplant Library (ormation .In order to make a more manageable prioritisation survey (based upon previous JLA experience), remaining indicative questions submitted by three or more individuals to the initial survey were brought forward for prioritisation. A second online survey was designed and piloted in which respondents were asked to rate each remaining question on a five-point Likert scale from “Not at all important” to “Extremely important”. Following an initial pilot, a glossary of terms was also developed to help non-professional respondents understand some of the medical terminology used in the questions. Demographic characteristics of respondents were also collected, including age, sex, geographical region, ethnicity and role. The second survey was open from October to December 2015, and was promoted in a similar way to the initial survey. All respondents to the initial survey were contacted to participate in prioritisation, although this survey was also open to individuals who had not previously participated in the process. Only one response per participant was allowed.Responses to the prioritisation survey were collated and the Likert scale coded numerically from 1  to 5 (Extremely important). The overall mean score as well as the mean score for patients, donors and professionals were calculated for each question. Results were reviewed by the steering group, and the decision was made to take the top 25 ranked questions overall through to the final workshop.A final one-day workshop was held in London in February 2016. The aim of the workshop was to agree a top-ten list of prioritised questions for future research. Professionals , patients and donors from partner organisations were invited to attend and contribute via contact details submitted to the two surveys, as well as organisation mailing lists, social media and websites. Participants were selected with the aim of broad representation of all involved groups and organisations. We initially planned to include around 25 participants in the final workshop, based upon optimal numbers for interaction during previous JLA PSPs, as well as budget and space constraints. Due to illness and unexpected work commitments, 20 individuals eventually participated.The workshop took the form of a modified nominal group process facilitated by experienced JLA advisors. Participants were asked to rank the remaining 25 questions prior to attending the workshop, and in an initial small group session these responses were discussed to identify any agreement in the top and bottom three priorities. In a second small group session the groups were asked to rank the uncertainties based upon this discussion. Groups were balanced to ensure equal professional and non-professional involvement and the facilitators encouraged all participants to take part and voice their opinions. Results of this ranking process from each small group were fed back to the meeting as a whole, with agreement in the top and bottom ranked questions highlighted. A further small group round (with different group composition) took place to revise ranking based upon this feedback. In the final whole group session, the results of the small group discussions were used to suggest a top-ten ranking, and discussion took place as to whether items should be removed or inserted into the top ten. Where there was disagreement, all participants were asked to vote in order to reach a decision. The results of the interim prioritisation survey  were made available on request throughout the meeting to help inform debate and decision making. At the end of the meeting, a final top-ten questions were agreed as priorities for future research.The initial survey received 440 potential research questions from 183 respondents. Responses were from a mixture of professionals (36.1%), patients (37.7%), carers (2.2%) and live donors (21.9%), although some donors also identified themselves as carers for a transplant recipient. Full demographic details of respondents are described in Submitted questions covered the breadth of kidney transplantation, and were categorised as relating to recipient assessment, recipient education, access to the waiting list, organ allocation, management of highly sensitised recipients, organ preservation and reconditioning, live donor transplantation, non-directed donation, tissue typing and immunology, ABO and HLA incompatible transplantation, surgical technique and intra-operative management, post-transplant complications, acute and chronic rejection, recurrent disease, psychosocial outcomes, diet and lifestyle, management of the failing transplant, immunosuppression and tolerance, paediatric and adolescent transplantation and organ bioengineering.The flow of questions through the PSP process is outlined in The interim prioritisation survey received 256 responses from a mixture of patients (30.5%), carers (4.3%), donors (10.9%) and professionals (54.3%). Full demographic details of those responding are described in There was evidence of a difference in priorities between patients, donors and professionals. Of the 25 top-ranked questions, there was a difference in rankings of greater than 5 places between patients and professionals for 16, between donors and professionals for 18 and between patients and donors for 17. Whilst all groups prioritised questions regarding improving long-term transplant outcomes, patients tended to prioritise questions about immunosuppression (including side effects), organ preservation and equity of access. Professionals prioritised questions about assessment of patient and organ suitability and management of antibody mediated rejection. Donors prioritised questions regarding assessment of organ suitability and promotion of living donation. The questions taken to the final workshop represented a mixture of those prioritised by all three groups.Twenty participants took part in the final workshop, representing patients (7), donors (4) and professionals (9). During the day, it was decided that two of the questions had some degree of overlap (regarding organ preservation and conditioning) and the group agreed to merge them together. The top ten research priorities agreed are listed in Of particular note was the desire of the participants in the final workshop to include realistic questions achievable in the short term (for example those relating to the management of immunosuppression) as well as questions that seem much further away from reality such as the development of bioengineered organs and induction of tolerance. The most highly prioritised question from the interim survey (“What is the best strategy to prolong the life of the transplant kidney?”) was felt by the group to be too generic and covered by many of the more specific questions under consideration, and so was not included in the final top ten.A number of questions considered during the process were submitted by non-professionals, and would not have been considered without their involvement. Of the 90 indicative questions 41 (45.5%) were submitted by professionals alone and 14 (15.6%) were submitted by non-professionals alone; the remainder were submitted by both groups. Four questions submitted by patients alone were taken through to the prioritisation stage. Of the final top ten questions, six were originally submitted by both patients and professionals, and four by professionals alone.The final top ten reflected the mixed priorities of all groups. Of the ten, five appeared in the patient top ten during the prioritisation survey, four in the professional top ten, and two in the donor top ten. Four of the final ten were ranked more than five places higher by patients than professionals, and four were ranked more than five places higher by professionals.www.transplantpsp.org/kidney) and the JLA website (http://www.jla.nihr.ac.uk). They were also disseminated to all partner organisations and participants involved in the process, many of whom are involved in or fund transplant research. The James Lind Alliance is part of the National Institute for Health Research (NIHR), one of the largest funders of health research in the UK. The results of the Kidney Transplant PSP have been discussed with NIHR representatives in detail with the aim of taking forward priorities for future specific funding calls.The final list of priorities, as well as all research questions identified, have been made available on the internet through both the PSP website , and the methodology used fulfils many of the criteria defined for good practice in priority setting [The JLA process followed has now been used to identify research priorities in over 35 areas of medicine . The final top ten included questions ranked highly by all groups during the prioritisation process, with an equal mixture of those ranked highly by professionals and non-professionals. It is likely, therefore, that patient involvement played an important role in the shaping of the final prioritised list.A recent systematic review identified four existing publications outlining research priorities with a scope including kidney transplantation . Of thesThe current process may under-represent certain groups affected by transplantation. In particular, very few responses were received from children and adolescents despite partnership with children’s renal charities and the British Association for Paediatric Nephrology. However, many respondents were parents of affected children or nephrologists involved in the treatment of these patients, and questions regarding child and adolescent transplantation were considered during the final workshop. The other patients under-represented in the current process are those from black, Asian and minority ethnic (BAME) groups. These groups made up around 9% of the responses to the initial survey, and 5% of those to the prioritization survey, yet represent around one quarter of the patients on the UK transplant waiting list. BAME patients have significantly higher waiting times to transplantation in the UK, and are less likely to donate . QuestioA further limitation of the current process is the relatively small number of participants in the final workshop. A group size of around 25 participants was determined to provide optimal interaction based upon experience from previous JLA PSPs, and within the budget limitations of the project. Unfortunately, due to illness and unforeseen work commitments the final number of participants was reduced to 20. Despite this, the final group had fair and balanced representation from all stakeholder groups including patients, donors and clinicians. Furthermore, discussions during the final workshop were informed by the rankings of all groups during the prioritisation survey, meaning that the final decision making was influenced by a broader group than just those involved in the workshop.Whilst the prioritised results of this PSP are most relevant to the UK healthcare setting, it is likely that the long-list of potential research questions has international relevance. The review process to check whether questions were truly unanswered by existing literature included evidence from all international healthcare settings, and so whilst it is conceivable that priorities may differ, the unanswered questions are likely to remain the same. This notion is supported by comparison of questions submitted to the current process and those submitted to previous prioritisation processes in other healthcare settings, with significant overlap seen despite differences in priority . One cavPriority setting should not be seen as a one-time exercise, and the priorities set in this process will require future re-evaluation to ensure continuing relevant or to identify new areas of important uncertainty . As yet,The Kidney Transplant PSP has provided an invaluable resource of prioritized, unanswered research questions to help in the design of future research studies. By increasing awareness of these topics, we hope to divert research effort and funding towards the design and implementation of high quality studies, including collaborative randomised controlled trials, with the goal of improving access to transplantation and the long-term outcomes for both donors and recipients.S1 File(DOCX)Click here for additional data file.S2 File(DOCX)Click here for additional data file.S3 File(DOCX)Click here for additional data file.


The humidity sensor consists of an optimally designed porous top electrode, a functional polymer humidity sensitive layer, a bottom electrode, and a glass substrate. The porous top electrode is designed to increase the contact area between the sensing layer and water vapor, leading to high sensitivity and quick response time. The functional polymer mixed with TiO2 microparticles shows excellent hysteresis under a wide humidity-sensing range with good long-term stability. The results show that as the relative humidity ranges from 10% RH to 90% RH, the proposed humidity sensor achieves a high sensitivity of 0.85 pF/% RH and a fast response time of less than 35 s. Furthermore, the sensor shows an ultra-low hysteresis of 0.95% RH at 60% RH, a good temperature dependence, and a stable capacitance value with a maximum of 0.17% RH drift during 120 h of continuous test.In this study, a high-sensitivity and low-hysteresis porous metal–insulator–metal-type capacitive humidity sensor is investigated using a functional polymer mixed with TiO Humidity sensors have been widely used in our daily lives and have become increasingly important in different applications such as meteorology, agriculture, smart homes, medical equipment, and biotechnology ,2,3,4. VIn capacitive humidity sensors, the material of the humidity-sensing layer is one of the most important components. Many types of materials, such as electrolytes ,14, cera2 microparticles. The porous top electrode increases the contact area between the functional polymer sensing layer and the environment, resulting in high sensitivity and fast response time. A functional polymer is proposed by mixing an organic polymer with TiO2 ceramic-based microparticles to achieve ultra-low hysteresis and enhance the humidity-sensing range. The humidity characteristics of the sensor have been tested in various relative humidity conditions. The use of a well-designed porous top electrode and a functional polymer mixed with TiO2 microparticles can improve the properties of the humidity sensor; thus, high sensitivity, low hysteresis, fast response time, and wide humidity-sensing range can be realized.The current paper proposes a high-sensitivity and low-hysteresis metal–insulator–metal (MIM) capacitive humidity sensor using a well-designed porous top electrode and a functional polymer mixed with TiO2 microparticles is proposed for the humidity-sensing layer; it exhibits low hysteresis and good linearity to humidity. The proposed functional polymer is composed of pyromellitic dianhydride (PMDA)–oxydianiline (ODA), which is formed from the polyamic acid precursor of PMDA and ODA with mixed TiO2 microparticles to form a composite material in a weight ratio of 1:1.5, which can fully mix together and good for the water vapor absorption and desorption to realize a high sensitivity and low hysteresis. The average grain size of the TiO2 microparticles is less than 0.1 µm; they are of the rutile type with a dielectric constant of 3.9. Titanium dioxide is a very useful additive, which can improve the hysteresis behavior and humidity-sensing range of the polymer for humidity detection.The porous MIM-type capacitive humidity sensor, having a size of 4 mm × 5 mm, consists of a glass substrate, a bottom electrode, a functional polymer film as a sensing layer, and a top electrode with holes. 2/N2H2 plasma descum step. (e) The polymer is etched using CF4/O2 in a BMR inductively coupled plasma (ICP) asher with a chamber temperature of 81 °C and ICP power of 900 W for 3 min. Some TiO2 residue remains after this etching process. (f) A TiO2 residue removal method was previously proposed by our team [2/N2H2 plasma descum step. (i) A 1000/1000/3000 Å-thick Ti/Pt/Au metal layer is formed by e-beam evaporation, which is used as the top electrode. (j) Finally, a lift-off process is used to create the top electrode on the patterned photoresist layer.The substrate used in the fabrication is a 6 in. glass wafer. The fabrication process of the porous MIM-type capacitive humidity sensor is shown in our team . We founThe fabricated porous MIM-type capacitive humidity sensors are shown in pp; the relative humidity (RH) is used to fit experimental results. The chamber fluctuations in terms of temperature and humidity are ±0.3 °C and ±2.5% RH, respectively. First, we fix the sensors on the measurement board and place it into the humidity-generating chamber. Then, we use coaxial lines, which have low online losses, to connect the measurement board to the LCR meter through a hole on the side wall of the chamber using a good sealant. The varying capacitances can be recorded in real time on the computer through a USB connection with the LCR meter. Before the measurement process, the fabricated humidity sensors were dried and stored in a desiccator to maintain the initial absorbed moisture level close to zero. The chamber humidity was increased from 10% RH to 90% RH and then decreased back to 10% RH in steps of 10% RH; the measurements were taken at 30 min intervals to ensure full sorption/desorption of water vapor.C of the MIM capacitive humidity sensor is expressed as2 microparticles, A is the effective sensing area of the humidity sensor, and d is the thickness of the sensing layer. The permittivity of the polymer changes proportionally with the high dipole moments of water molecules. Therefore, this humidity change is directly detected by measuring the changes in the capacitance. The relative permittivity of the polymers in room conditions is approximately 5, while that for pure water is far greater (around 80). When water vapor is absorbed by polymers, the apparent permittivity value will increase, resulting in a linear increase in capacitance with relative humidity.Capacitive humidity sensors respond to humidity variations by varying their dielectric permittivity, and this variation is directly proportional to the ambient vapor changes. The ideal capacitance D) and spaces between the adjacent holes (L). The sensors show linear outputs with high sensitivity using the functional polymer mixed with TiO2 microparticles. The sensitivity S of the humidity sensors can be expressed asC90 and C10 denote the capacitance obtained at 90% RH and 10% RH, respectively. The 90 and 10 values are the highest and lowest RH values in the variation range, respectively. The sensitivity of the humidity sensor with different hole diameters (20 µm to 100 µm) is shown in 2 ceramic-based microparticles. The role of the TiO2 microparticles can be explained using an ionic conduction model [2 microparticles to form hydroxyl groups. When more water is further adsorbed, each water molecule is hydrogen-bonded to two hydroxyls; then, a liquid-like layer of hydrogen-bonded water molecules is formed, in which each water molecule is only singly bonded to a hydroxyl group. This process could effectively suppress the water clusters in the polymer, resulting in low hysteresis.Hysteresis is a critical drawback of capacitive humidity sensors. It may cause deformation of the polymer owing to water clusters and consequently influence the sensor performance. To reduce the hysteresis, a functional polymer is proposed by mixing an organic polymer with TiOon model . The watH of 0.95% RH at 60% RH, which is calculated byCD60 and CA60 are the capacitance values measured at 60% RH in the desorption and absorption process, respectively. 2 microparticles reduces the hysteresis value.The capacitance variation with the humidity is measured to investigate the hysteresis behavior of the humidity sensor, as shown in The response time is verified by the capacitance variation of the humidity sensor when the ambient humidity is abruptly changed from room conditions to 90% RH. The experimental setup was constructed as follows. The chamber was kept at 90% RH steadily. The humidity sensors were put into the 90% RH chamber at room humidity level through the hole in the chamber. The LCR meter was connected to the humidity sensor throughout the entire process, and it measured the response time at the 90% RH point of the final steady-state capacitance value after an abrupt capacitance change. The response times of the same humidity sensor at three different temperatures  were measured. To determine whether the temperature influences the sensitivity of the humidity sensor, the capacitance changes at three different temperatures  are measured. 2 microparticles. The magnitude of the drift of sensor capacitance is converted into the apparent changes in relative humidity, D, which is calculated by [The long-term stability is tested to investigate the practical value of the humidity sensor. The sensors are placed in an ambient chamber for 120 h at 10% RH, 50% RH, and 90% RH. lated by (4)D=C(m2, organic polymer without TiO2, and the other referenced sensors. The proposed humidity sensor, which employs a functional polymer mixed with TiO2 microparticles, realizes high sensitivity, low hysteresis, fast response time, and wide humidity-sensing range.2 microparticles and a porous top electrode structure was designed to improve the performance of MIM-type capacitive humidity sensors. This work demonstrated a high sensitivity of 0.85 pF/% RH and a fast response time of less than 35 s, which can be achieved by the hole structure on the top electrode. Furthermore, this research achieved an ultra-low hysteresis of 0.95% RH and a wide humidity-sensing range from 10% RH to 90% RH, which can be realized by the functional polymer mixed with TiO2 microparticles. Finally, a good temperature-independent and stable capacitance value with a maximum of 0.17% RH drift was shown to be sufficient for use in a reliable humidity sensor for various applications.A novel humidity-sensitive layer composed of a functional polymer mixed with TiO


In this work, the work function (WF) of graphenes, which are used as electronic devices, has been designed and evaluated by using the first-principle approach. Different states of graphene were considered, such as surface modification, doping, and defects. Firstly, WF strongly depends on the width of pristine graphene. A bigger width leads to a smaller WF. In addition, the effects of hydroxyls, defects, and positions of hydroxyls and defects are of concern. The WF of the graphene which is modified with hydroxyls is bigger than that of the pristine graphene. Moreover, the WF value increases with the number of hydroxyls. Positions of the hydroxyls and defects that deviated from the center have limited influence on the WF, whereas the effect of the position in the center is substantial. Lastly, B, N, Al, Si, and P are chosen as the doping elements. The n-type graphene doped with N and P atoms results in a huge decline in the WF, whereas the p-type graphene doped with B and Al atoms causes a great increase in the WF. However, the doping of Al in graphene is difficult, whereas the doping of B and N is easier. These discoveries will provide heavy support for the production of graphene-based devices. As a material that possesses a variety of excellent performances, graphene –3 has beGraphene WF measured via experiment is approximately at 4.2 to 4.8 eV , 13. The3 solution to adjust the WF  in uniform electron gas. Both GGA and LDA have been used for the calculations in two-dimensional materials. Lebègue et al. found that the band structure of two-dimensional materials obtained using either LDA or GGA is very similar [The generalized gradient approximation (GGA) and local density approximation (LDA) are the exchange–correlation functionals commonly used in quantum mechanics calculations. They are described in Eqs.  and 2)::2):1\doc similar . At the  similar , 34.−6 eV, and the MAX force is 0.03 eV/Å.As for the WF, the previous scanning probe-based studies had shown that the WF is measured as 4.6 eV, such as with graphite . GeneralV0) and the Fermi level (Ef), as shown in Eq.  is the energy of pristine GNRs, E+ d)(GNRs  is the energy of doped GNRs, d is the doping atom, n is the number, and EC and Ed are the chemical potentials determined for carbon and doping atoms.where The formation energy can be used to evaluate whether the feasibility of using atoms for doping is good or not. The smaller the formation energy is, the easier the doping becomes. Figure The WF of graphene in different states, such as surface modification, doping, and defects, are investigated in this study. Basically, the WF decreases as graphene width increases. For the hydroxyl modification, the WF is large when the number of hydroxyls increases. Furthermore, when the distribution of hydroxyls is intensive, the WF is also increased. The defect would decrease the graphene WF, which does not depend on the positions. The p-type doping with B and Al would lead the WF to increase; however, the increased amount is determined by the dopants. The n-type doping with N and P reduces WF greatly. These discoveries will provide a theoretical support in controlling graphene and further improving the design of graphene-based devices.