Bony union is a primary predictor of outcome after surgical fixation of long bone fractures. Murine models offer many advantages in assessing bony healing due to their low costs and small size. However, current fracture recovery investigations in mice frequently rely on animal sacrifice and costly analyses. The modified Radiographic Union Score for Tibia fractures (mRUST) scoring system is a validated metric for evaluating bony healing in humans utilizing plain radiographs, which are relatively inexpensive and do not require animal sacrifice. However, its use has not been well established in murine models. The aim of this study was to characterize the longitudinal course of mRUST and compare mRUST to other conventional murine fracture analyses. 158 mice underwent surgically created midshaft femur fractures. Mice were evaluated after fracture creation and at 7, 10, 14, 17, 21, 24, 28, 35, and 42 days post-injury. mRUST scoring of plain radiographs was performed by three orthopaedic surgeons in a randomized, blinded fashion. Interrater correlations were calculated. Micro-computed tomography (μCT) was analyzed for tissue mineral density (TMD), total callus volume (TV), bone volume (BV), trabecular thickness, trabecular number, and trabecular separation. Histomorphometry measures of total callus area, cartilage area, fibrous tissue area, and bone area were performed in a blinded fashion. Ultimate torque, stiffness, toughness, and twist to failure were calculated from torque-twist curves. A sigmoidal log-logistic curve fit was generated for mRUST scores over time which shows mRUST scores of 4 to 6 at 7 days post-injury that improve to plateaus of 14 to 16 by 24 days post-injury. mRUST interrater correlations at each timepoint ranged from 0.51 to 0.86, indicating substantial agreement. mRUST scores correlated well with biomechanical, histomorphometry, and μCT parameters, such as ultimate torque , manual stiffness , bone percentage based on histomorphometry , cartilage percentage , tissue mineral density , BV/TV based on μCT , and trabecular thickness , among others. These data demonstrate that mRUST is reliable, trends temporally, and correlates to standard measures of murine fracture healing. Compared to other measures, mRUST is more cost-effective and non-terminal. The mRUST log-logistic curve could be used to characterize differences in fracture healing trajectory between experimental groups, enabling high-throughput analysis. Approximately 1.1 million human bone fractures are treated annually in the United States (US). In fact, long bone fractures comprise 10% of all non-fatal injuries and incur an estimated inpatient expenditure of $10.4 billion annually in the US . These aIn vivo μCT allows for the generation of longitudinal data, and studies have identified protocols for non-invasive monitoring of rodent fracture healing  scanning provides quantitative, three-dimensional measurements of both the structure and mineralization of the fracture callus. In fact, numerous studies have demonstrated that CT-based measurements directly correlate with callus stiffness and strength , 4. In t healing –8. Howev healing  found th healing  develope healing , 12. AddDespite the success of mRUST in human studies, there is no accepted methodology for utilizing plain radiographs to assess fracture healing in mouse models. The standard measures of fracture healing in mice include biomechanical testing, μCT analysis, and histomorphometric analysis, which are associated with significant time and costs . Should All animal procedures were performed with prior approval from Indiana University School of Medicine Institutional Animal Care and Use Committee. All experiments were performed in compliance with NIH guidelines on the use and care of laboratory and experimental animals. Three month old male, C57BL6/J mice were purchased from Jackson Laboratories  and housed in the Indiana University School of Medicine Laboratory Animal Resource Center under a 12-h light, 12-h dark cycle for 6 weeks. Food and water were provided ad libitum.Mice were anesthetized using 1.0% isoflurane for induction and 0.6-0.8% for maintenance, at 1000 mL/minute utilizing a SomnoSuite Low-Flow Anesthesia System (Kent Scientific). Analgesia was provided by 1.0mg/kg of buprenorphine sustained-release subcuticular fashion pre-operatively. The right leg was shaved and scrubbed with betadine followed by ethanol (triplicate scrubs). All instruments and implants were autoclaved before use. A surgically created mid-shaft femur fracture was utilized as previously described . In brieAnteroposterior (AP) and lateral X-ray imaging at the aforementioned time points were obtained using a Kubtec Xpert80 X-ray system . All images were taken using a set of standardized imaging parameters to ensure direct comparisons within and across specimens. AP radiographs were obtained by placing the mouse on its left  hip. A small piece of tape was used to gently pull the surgical leg laterally and downwards while ensuring that the tail was not overlapping the femur  and lateral (anterior and posterior cortices) X-rays as follows: 1 = no healing; 2 = callus present, no bridging; 3 = bridging callus, fracture line visible; 4 = bridging callus with no fracture line visible. The scores for all 4 cortices were summed to provide a final score ranging from 4  to 16 . Mean mRUST scores were calculated for each specimen at each time point, and interrater correlations were calculated.Mice were euthanized at the indicated time points using carbon dioxide gas and cervical dislocation. Both the fractured and unfractured femora were harvested and cleaned of subcutaneous tissue and muscle before analysis. The intramedullary needle was removed using a needle driver to facilitate histologic sectioning and limit metal artifact during μCT analysis. Femora designated for histomorphometry and μCT were fixed in 10% neutral buffered formalin for 48 hours and then rinsed and stored in 70% ethanol at 4°C. Femora designated for μCT and biomechanical analysis were wrapped with gauze soaked in deionized water and stored at -20°C.3. The long axis of each femur was aligned with the vertical axis of the scanner. Femurs were imaged using a Bruker SkyScan 1172 desktop imaging system with X-ray tube voltage 59kV, intensity 167μA, rotation step 0.7°, integration time 885ms, and voxel size 9.83μm. Scanned images were then reconstructed into 3D image stacks  with smoothing 2, beam hardening 20%, ring artifact 5, and a dynamic image range with minimum and maximum attenuation coefficients of 0 and 0.75. They were then analyzed using CT Analyzer software . The region of interest was the entire fracture callus determined by manual and automated techniques. The proximal and distal boundaries of the callus were identified manually. Next, a custom script was utilized to trace the fracture callus excluding the cortical bone and marrow areas. Bone was differentiated from non-bone by a single global threshold grayscale index of 90. Recorded measures included: tissue mineral density (TMD), bone volume (BV), tissue volume (TV), bone volume/tissue volume (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), and trabecular number (Tb.N).Analyses were conducted after all mice were euthanized and all specimens were treated at the same time to minimize batch to batch variation. For μCT analyses, the scanner was calibrated using two phantom rods 2mm in diameter, at concentrations of 0.25 and 0.75 g/cmFemora harvested for histomorphometric analysis were decalcified in Immunocal™ Decalcifier  at pH 7.2-7.4 for 48 hours. Longitudinal paraffin sections of 5 μm thickness were prepared and the center-most section from each femur was stained with picrosirius red and alcian blue. Brightfield and polarized images were obtained from a Leica DM2700M microscope. Histomorphometric measures of total callus area, cartilage area, fibrous tissue area, and bone area were performed in a blinded fashion using an image manipulation program  .For femora undergoing biomechanical analyses, frozen femora were rehydrated in Dulbecco’s phosphate-buffered saline (DPBS) with calcium and magnesium at room temperature for 16-24 hours. Femora underwent immediate biomechanical torsion analysis after μCT to prevent repeated freeze-thaw cycles and to maintain structural integrity of the bone. Femora were potted into 0.38 bullet casings and held in place with orthodontic resin . The resin was allowed to harden for 5 minutes prior to testing. Biomechanical testing was then performed in torsion at 1 degree/second until failure using a Mark-10 advanced torque-testing system . Ultimate torque, stiffness, toughness, and twist to failure were calculated from the resultant torque-twist curves. Ultimate torque was defined as the maximum torque sustained, manual stiffness was defined as the slope of the torque-twist curve over 50-75% of the ultimate torque, maximal stiffness was defined as the greatest slope over a 5 degree segment of twist, toughness was calculated as the area under the torque-twist curve, and twist to failure was defined as the twist to failure after 25% of the ultimate torque was reached on the torque-twist curve (Continuous variables were summarized by means and standard deviations (SDs). Gwet’s AC2 was calculated to quantify the interrater reliabilities of mRUST scores. The average mRUST scores across raters were then used for subsequent analysis. Spearman’s correlation coefficients were calculated between the mRUST scores and other measures because these associations appeared to be monotonic but nonlinear. For the temporal trend of mRUST scores, a nonlinear mixed effects model was fit with a log-logistic curve as the mean function as follows:Y(0) a known initial value at day zero (mRUST=4 by definition), Y∞ is the upper asymptote at the end of the fracture healing, k is the healing rate, and X0.5 is when half the healing is complete. The log-logistic curve also has an inflection point where the fastest healing happens. Random effects of INLINE, k, and X0.5 were included. All analyses were performed using SAS 9.4 , and p<0.05 was considered statistically significant.where ∞) as 15.38, the inflection point (X0.5) as 12.08 days, and the rate (k) as 4.43. Additionally, this curve has approximate exponential growth, transitional, and plateau phases beginning at 7-, 17-, and 28-days post injury, respectively, which reflects the expected timeline of fibrocartilaginous callus, bony callus, and remodeling phases of fracture healing in mice.For mRUST to be a viable metric of murine fracture healing, it should correlate well with traditional measures. Biomechanical testing offers the most direct quantification of bone’s ability to support efficient locomotion and is thus pivotal for determining the functionality of the end product of fracture repair. As observed in Histological staining followed by histomorphometry offers another avenue for assessment of the fracture callus that is best for differentiating between tissue types . As detailed in Micro-computed tomography enables high‐resolution visualization of fracture callus architecture, and resolution of fracture related deficits in μCT parameters often correlates with restoration of mechanical function. As shown in The goal of this study was to assess the validity of mRUST X-ray scoring as a metric of fracture repair outcomes in mice. X-ray evaluation is pivotal in gauging fracture repair success clinically. In fact, the FDA defines non-union solely based on radiographic criteria and definitions of non-union in orthopaedic research include radiographic criteria more often than clinical criteria (62% vs 45%) . SeveralDespite the known predictive value and reliability of RUST/mRUST scoring of fracture repair success, there is minimal evidence supporting its use in animal models , 19–22. In the study by Cooke and colleagues , the autFiset et al.  performeTo our knowledge, RUST and mRUST have been used as metrics to examine non-RUST and mRUST related hypotheses in few rodent studies. Meeson et al.  implemen∞), an increased or unchanged rate (k), and an earlier inflection point (X0.5). Additionally, although mRUST appears to correlate well with other modalities of fracture repair assessment, if and how these correlations may be disrupted in various disease states and following experimental interventions is unclear. For instance, Cooke et al. . We chose radiographic assessment, as this is the most commonly used clinical modality and is less technically demanding/time intensive compared with other protocols for rodent non-invasive longitudinal monitoring of fracture healing. Our purpose is not to supplant other modalities, but rather to investigate whether quantitative evaluation of mRUST would at all be of use when applied longitudinally to radiographic evaluation. We demonstrate that it is a feasible technique, has reasonable correlations to standard measures of rodent fracture healing, and we uniquely provide a “mathematical” description of routine fracture healing based on mRUST scoring over time that could be valuable for future studies. X-rays may also be useful in cases where the more advanced imaging modalities are not available.Several limitations to our study exist. We had only three raters and do not know how this would fair with a larger number of raters with varying degrees of experience. Another limitation is that we intended to house five mice per cage. Over the course of the study, some were split due to aggression or other behavior based on veterinarian and/or study personnel observation. This may have contributed to variation in measured parameters as previously described . AdditioIn conclusion, mRUST is a reliable, cost-effective, and non-terminal measure to follow fracture healing longitudinally in murine models. It follows a consistent trend that reflects the phases of fracture repair and correlates well with traditional metrics of fracture repair. We predict that implementation of the log-logistic mRUST curve will enable accurate and meaningful representation of various alterations in fracture repair following experimental intervention. This will facilitate characterization of healing trajectory in endocrine disease states, such as menopausal osteoporosis, glucocorticoid use, renal osteodystrophy, pituitary disease, and anorexia nervosa, as well as assess the efficacy of potential treatments. For large exploratory studies , a shift in parameters and phases of the log-logistic curve could be used to gauge general impact on fracture healing. Upon finding a change in mRUST healing trajectory, more detailed experiments involving μCT, histomorphometry, biomechanics and other assessments could be undertaken at targeted time points. In this way, longitudinal mRUST trajectories could expedite discovery of new fracture healing interventions for further investigation.The original contributions presented in the study are included in the article/supplementary material. Further inquiries can be directed to the corresponding author.The animal study was reviewed and approved by Indiana University School of Medicine Institutional Animal Care and Use Committee.RN, MK, CC and T-MC conceived of the idea, designed the experiments and assisted with data interpretation and manuscript preparation. MK provided equipment, funding and other resources. VA, AK, CS, AM, JC, SM, MS, RB, UD, CC, JL and RN participated in conducting experiments and acquisition of data. ZL curated data and performed formal analyses. VA and AM drafted original manuscript. All authors assisted in editing the manuscript, approve of the final version, and take responsibility for the accuracy and integrity of the work.Funding for these studies was provided in part by the NIH . This work was also supported in part by Indiana University School of Medicine, the Indiana Center for Musculoskeletal Health, the Stark Neuroscience Research Institute, and the Department of Orthopaedic Surgery. This material is also the result of work supported with resources and the use of facilities at the Richard L. Roudebush VA Medical Center, Indianapolis, IN: VA Merit #BX003751. The presented contents are solely the responsibility of the authors and do not necessarily represent the official views of any of the aforementioned agencies.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


The study aimed to evaluate the contribution of building problems to mold proliferation in dwellings. We investigated 503 dwellings of patients suffering from respiratory diseases, whose attending physicians had requested a home inspection if the area of mold was equal to at least one square meter. After careful visual evaluation and basic environmental measurements performed by a trained technician, environmental issues were classified into building defects, accidental water damage, and condensation. Data analysis demonstrated that building defects were the pre-eminent cause of mold proliferation. Among the building defects, water infiltration through leaks in roofs or walls was the leading cause. These results highlight the need for health professionals managing patients with respiratory diseases to be able to request a home inspection, and for city health authorities to commission professionals who can focus on building problems and find ways to address them. Mold proliferation has been identified in around 20% of dwellings in Europe  and the Several governmental and nongovernmental organizations around the world have issued guidelines on the health impacts of indoor mold ,4,5. HomIn practical terms, when a home inspection is performed, the technician should be able to identify the leading cause of mold proliferation.This paper aimed to identify the leading causes of mold proliferation, following home visits to buildings with mold problems. This issue is crucial because it affects the way in which the building will be managed: either through remediation undertaken by professionals in the case of structural defects, or simple adjustments or counseling in the case of inappropriate occupant behavior.Five hundred and three dwellings with mold were studied. A dwelling was considered to have mold if the sum of the surfaces with mold in the living areas  was equal to at least 1 square meter . The inThe technician first performed a careful visual inspection of the dwelling. In each room, they located possible sources of air pollution by checking the condition of the joinery and heaters, maintenance of combustion appliances, looking for spots of mold, and checking the ventilation. They also had a discussion with the tenant concerning the living habits of the family and, in particular, the use of cleaning products.The technician then completed a questionnaire regarding the above items, and also the number of occupants.-A Qtrack to measure ambient temperature and relative humidity ;-A mural hygrometer );-A light paper sheet and a smoke canister to check the efficiency of mechanical ventilation .Then, various types of equipment were used in the living room and the patient’s bedroom, as follows:-Building defects: rising dampness, water infiltration through leaks in the roof and/or external walls, thermal bridge;-Accidental water damage resulting from a sudden disruption of the water pipes;-Vapor condensation on walls and/or ceiling. Measurement of wall humidity allowed the cause of mold development to be identified as either vapor condensation  or a water leak .At the end of the visit, environmental issues were classified into three different groups:The study group included 67 dwellings without structural defects, and 436 with at least one defect. The mean number of occupants per dwelling was equal to 6.25, although the mean figure for this area is 2.5 [This study has strengths and limitations. Its strengths are the large sample size and the standardization of the visits performed by a single trained technician. Nevalinen et al., have demonstrated that occupants missed signs of current or previous mold problems in 15% of houses surveyed . In addiExisting literature has highlighted many different risk factors for mold development: age of the building , number From the abovementioned results, it is clear that building problems are the number one cause of mold proliferation. Indeed, in addition to the “building problems” category, such problems also feature in the “condensation” category when condensation is caused by thermal bridges, and a lack of proper ventilation systems.To the best of our knowledge, this is the first demonstration of the pre-eminence of building problems as the main causes of mold proliferation. Inappropriate building usage is shown to be merely a contributory factor. Therefore, city health authorities and home inspections should first focus on possible building defects. Similarly, health professionals who manage patients suffering from respiratory diseases that may be related to mold proliferation should advise these patients to ask for a home inspection, because it is unlikely that the common advice they offer, concerning ventilation and cleaning moldy surfaces, will resolve the issue.In this study, we aimed to identify the causes of mold proliferation in dwellings. In inner-city high-rise buildings, building problems are the main cause of mold proliferation. This result is likely to apply to this type of building in other locations, but not necessarily to other types of housing in other climates. These findings point to the need for home inspections by professionals so that the defects identified can be correctly addressed.


Graphene field-effect transistors (GFETs) exhibit unique switch and sensing features. In this article, GFETs are investigated within the tight-binding formalism, including quantum capacitance correction, where the graphene ribbons with reconstructed armchair edges are mapped into a set of independent dual channels through a unitary transformation. A new transfer matrix method is further developed to analyze the electron transport in each dual channel under a back gate voltage, while the electronic density of states of graphene ribbons with transversal dislocations are calculated using the retarded Green’s function and a novel real-space renormalization method. The Landauer electrical conductance obtained from these transfer matrices was confirmed by the Kubo–Greenwood formula, and the numerical results for the limiting cases were verified on the basis of analytical results. Finally, the size- and gate-voltage-dependent source-drain currents in GFETs are calculated, whose results are compared with the experimental data. Graphene is a one-atom-thick planar sheet of carbon atoms in a honeycomb structure, whose free-standing monolayer was isolated and characterized for the first time in 2004 by Andre Geim and Konstantin Novoselov . This maWhen the semiconductor layer of a traditional metal–oxide–semiconductor field-effect transistor (MOSFET) is replaced by a graphene sheet, it is called as graphene field-effect transistor (GFET), whose source-drain current is extremely sensitive to the adsorbed molecules, and it is employable for use in gas and bio sensing ,7,8. Morsed CMOS . Among psed CMOS .Additionally, GFET has a singular capacitor behavior, since the graphene ribbon, being one of the parallel plates, possesses a very low charge density around the Dirac point, which may induce large variations in its chemical potential when a small amount of electric charge is introduced into the capacitor. This fact could significantly increase the potential difference between the back gate and the graphene, because it is equal to the difference between the chemical potentials at each plate. Such small quantities of charge generating a large potential difference lead to a lower capacitance compared to geometric or classic ones  , while tIn this article, the source-drain current  of an ideal parallel-plate capacitor with a dielectric material of thickness d and a relative permittivity e is the magnitude of the electron charge.In general, the capacitance per unit of area  in each transversal zig-zag line, as illustrated in W and L are integer numbers, H) of this graphene ribbon with null on-site energies can be written ast is the hopping integral of pristine graphene sheet and l and Let us consider an armchair-edged graphene ribbon with an even number of atoms n2D=∫f energy . CombiniT is given by , while R in turn increases with the ribbon length. Therefore, the asymmetry of Note in  in ref. , which i in ref. . In factThe correlation between source-drain current and gate voltage in graphene field-effect transistors (GFETs) is investigated by means of an atomic-scale tight-binding model, where mesoscopic graphene ribbons with edge reconstruction defects and transversal dislocations are addressed by an independent dual-channel transformation, which converts armchair-edged graphene ribbons into a set of independent dual channels.The electronic transport was studied within the Landauer formalism, and a new transfer matrix method has been further developed for each dual channel with nearest- and next-nearest-neighbor interactions, including aperiodically placed dislocations following a dilute Rudin–Shapiro (RS) sequence, which is one of the closest aperiodic arrangements to the random distribution. The Landauer conductance was confirmed by that obtained from the Kubo–Greenwood formula see , while tQuantized electrical conductance spectra are observed even in presence of edge reconstruction defects along mesoscopic graphene ribbons without dislocations, whose maximum value corresponds to the number of dual channels, while the multi-step behavior is softened at finite temperatures. In addition, the back gate voltage ( lengths .The approach of independent dual-channel plus renormalization method presented in this article can be used to study biosensor devices based on GFETs by considering adsorbed molecules as Fano impurities . This st


Due to its superhydrophobicity and sensitivity, this wearable sensor demonstrates efficient and stable monitoring of various underwater activities, including pressure, blowing, and tapping. Our approach provides an alternative idea for highly sensitive wearable sensors while broadening the practical application scope.Wearable pressure sensors have received widespread attention owing to their potential applications in areas such as medical diagnosis and human–computer interaction. However, current sensors cannot adapt to extreme environments  or show moderate sensitivity. Herein, a highly sensitive and superhydrophobic fabric sensor is reported based on graphene/PDMS coating. This wearable sensor exhibits great superhydrophobicity (water contact angle of 153.9°) due to the hydrophobic alkyl long chains and rough structure introduced by the Ar plasma. Owing to the network structure created by the electric-induced alignment of graphene sheets, an enhanced sensitivity (ΔI/I Wearable pressure sensors ,4,5,6,7 Researchers have introduced superhydrophobic material on the sensor surface to improve its resistance to harsh conditions. For example, Ni et al.  establisIn this experiment, a simple strategy was used to introduce an electric field into the preparation process of the conductive fabric to obtain a graphene interlayer-amplified structure. When an external force was applied, the additional structural deformation of the graphene sheet increased the sensor’s output. For underwater sensing, the polyester fabric obtained after plasma treatment had excellent superhydrophobicity and could be placed underwater to sense underwater motion (water contact angle (WCA) = 153.9°). New ideas were proposed for the design and development of future underwater intelligent equipment.2) were purchased from Miandu Textile Co., Ltd. . All fabrics were washed with Detergent 209 aqueous solution . The poly(dimethylsiloxane) precursor (MW770) was purchased from Alfa Aesar Chemical Company. Multilayer graphene (thickness less than 100 nm) was purchased from Kaisa  Materials Co., Ltd. Anhydrous ethanol (AR ≥ 99.7%) and argon (99.99%) were purchased from Changzhou Hongsheng Fine Detail Co., Ltd.  and Shanghai Haoqi Gas Co., Ltd. .Polyester fabrics  treatment. First, graphene and ethanol solutions were ultrasonically dispersed and exfoliated for 2 h, and the poly(dimethylsiloxane) precursor was then added to ultrasonic and mixed for 1 h . The preThe surface morphology of the polyester fabrics was tested using a field emission electron microscope . Water contact and rolling angles were measured using a professional A-200 instrument . The test system consists of an electrochemical workstation (CHI660E), a sensor, and a lab-built applied pressure device . An abra3 as -Si-CH2- under high-energy plasma and subsequent polymerization into -Si-CH2-CH2-Si- [-CH2-Si- ,21,22,23An electric field is applied to graphite nanosheets on PDMS substrates induce directional alignment of nanosheets. To clarify the effect of the electric field on the sensitivity of the fabric sensor, the response and recovery time of the sensor are measured when pressure is applied and removed from the sensor. As shown in μ). Here the dipole moment can be divided into two directions—the component parallel to the graphene sheet ||μ and the component perpendicular to the graphene sheet ⊥μ—and the force acting on the graphene sheet is the superposition of the two effects [However, the graphene nanosheets are not twisted completely parallel to the electric field, which may be due to the joint influence of the viscosity of macromolecules and the force between graphene nanosheets, and the movement of graphene nanosheets is greatly hindered by space. Therefore, the graphene nanosheets tend to move in one direction as a whole.  effects .T = μ × E, which is the driving force for the electric field to align the graphene, and the torque will try to twist the graphene, so that the graphene is aligned parallel to the electric field. However, due to the large aspect ratio of graphene, the generated dipole moment usually differs from the direction of the applied electric field force. The overall force acting on a graphene sheet is the superposition of moments caused by fields parallel and perpendicular to its axis; note that ||E = E × cosθ; ⊥E= E × sinθ, and θ is the angle between the direction of the DC electric field and sheet axis.The interaction between the electric field force and dipole moment produces an electric field-induced torque θ satisfies certain conditions, the total force can deflect the graphene sheet against the resistance in the system. If the directional arrangement of graphene is achieved under an electric field, the main consideration is the relationship between the torque and resistance of the system, and graphene starts to deflect when the torque generated under the electric field exceeds the sum of the resistance of the graphene in the system. Therefore, the choice of electric field strength is an important starting point for achieving the directional deflection of graphene.When 0, ΔI = I − I0, where I is the instantaneous current, I0 is the initial current at 0 kPa) is defined as the signal response of the pressure sensor, which can indirectly represent the sensitivity of the pressure sensor. The ΔI/I0 values initially increased and reaches an equal value then decreased as the dispersion concentration increased  and fast response time (~100 ms) due to the additional structural deformation obtained by the three-dimensional alignment of graphene under electric fields. The sensor can be used for pressure, water level, and underwater motion detection because it exhibits excellent superhydrophobicity (WCA = 153.9°) and good repeatability due to the formation of alkyl long chains and the rough surface under plasma. Moreover, stable superhydrophobic surfaces maintained good electrical conductivity when immersed in acid–alkali solutions with ultrasonic treatment. The sensor can be integrated into electronic circuits to provide warnings for preset pressures, or the fabric sensor could be used in underwater wearable devices to detect the pressure environment in which the human body is subjected to being underwater in real-time. We believe that this highly sensitive superhydrophobic fabric sensor provides an efficient strategy for wearable sensors, especially in wet or underwater environments.In summary, we have demonstrated a fabric pressure sensor with high sensitivity, good stability and good superhydrophobicity using the electric field synergistic plasma approach. The fabric sensor exhibits higher sensitivity (ΔI/I


Dysregulated brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB) signalling is implicated in several neurodegenerative diseases, including Alzheimer’s disease. A failure of neurotrophic support may participate in neurodegenerative mechanisms, such as ferroptosis, which has likewise been implicated in this disease class. The current study investigated whether modulators of TrkB signalling affect ferroptosis. Cell viability, C11 BODIPY, and cell-free oxidation assays were used to observe the impact of TrkB modulators, and an immunoblot assay was used to detect TrkB expression. TrkB modulators such as agonist BDNF, antagonist ANA-12, and inhibitor K252a did not affect RSL3-induced ferroptosis sensitivity in primary cortical neurons expressing detectable TrkB receptors. Several other modulators of the TrkB receptor, including agonist 7,8-DHF, activator phenelzine sulphate, and inhibitor GNF-5837, conferred protection against a range of ferroptosis inducers in several immortalised neuronal and non-neuronal cell lines, such as N27 and HT-1080 cells. We found these immortalised cell lines lack detectable TrkB receptor expression, so the anti-ferroptotic activity of these TrkB modulators was most likely due to their inherent radical-trapping antioxidant properties, which should be considered when interpreting their experimental findings. These modulators or their variants could be potential anti-ferroptotic therapeutics for various diseases. NTRK2; tropomyosin receptor kinase family) is a receptor for brain-derived neurotrophic factor (BDNF) and neurotrophin 4. The binding of ligands to the full-length TrkB receptor leads to ligand–receptor dimerisation and autophosphorylation of tyrosine residues in the intracellular kinase domain of the receptor [Tropomyosin receptor kinase B  ,5,6. BDNII(ATSM)), and by iron chelators such as deferiprone (DFP) [Ferroptosis, a unique form of iron-mediated regulated cell death, is executed by the build-up of lethal lipid hydroperoxides ,11,12. Ine (DFP) . Ferroptne (DFP) . TherefoGrowing evidence suggests that the ligand-activated TrkB signalling pathway mediates neuroprotection via amelioration of aberrant cellular responses such as inflammation ,17, oxidWe first screened different immortalised cell lines, such as N27, HT-22, HT-1080, and U-251, as well as primary cortical neurons for their TrkB expression and found that only mature primary cortical neurons express detectable levels of TrkB receptors a. Mature50 against RSL3: 19.2 μM) than in rescuing N27 cells (EC50 against RSL3: 72.1 μM).Independent studies have shown that the TrkB activators 7,8-DHF ,30 and p50 of 7,8-DHF: 24.3 μM; phenelzine: 40.9 μM), which was commensurate to the reference anti-ferroptotic RTA, Lip-1 (IC50 =22.7 μM)  c.50: 36~116 nM) and RSL3 (EC50: 29~73 nM), commensurate to Lip-1 in the following immortalised cell lines: N27, HT-22, and HT-1080  in the same cell lines: N27, HT-22, and HT-1080 a. We alsGrowing evidence of altered BDNF-TrkB signalling in neurodegeneration has spurred interest in understanding the possible underlying mechanisms. Ferroptosis is also implicated in neurodegeneration, and TrkB trophic signalling conceivably interferes with this pathway. Here, we reveal that several modulators of TrkB inhibit ferroptosis via a receptor-independent RTA mechanism.While BDNF is a potent agonist of the TrkB receptor, systemic therapy with BDNF has several pharmacokinetic limitations, such as short half-life, large molecular size, and poor blood–brain barrier (BBB) penetration. As an orally bioactive flavonoid, 7,8-DHF penetrates the BBB to act as an agonist of the TrkB receptor, and numerous preclinical studies ,30 demonTypical and fast-acting antidepressants bind to the TrkB receptor to exert biological and behavioural actions ,34. AntiANA-12 is a selective and potent antagonist of the TrkB receptor that penetrates the BBB , and K25GNF-5837 is a potent and orally bioavailable oxindole pan-Trk inhibitor with a mechanism similar to K252a . In our RPMI 1640 culture media (Cat# 72400120), penicillin and streptomycin (Cat#15140122), B27 (Cat#17504044), and MTT (Cat#M6494) were purchased from Thermo Fisher Scientific ; Foetal Bovine Serum ; Erastin (Cat#S7242), RSL3 (Cat#S8155), and 7,8-DHF (Cat#S8319) were purchased from Selleckchem ; FINO2 ; tBH solution (Cat#416665), BSO (Cat#B2515), deferiprone (Cat#379409), Lip-1 (Cat#SML1414), K252a (Cat#05288), recombinant human BDNF protein (Cat#B3795), phenelzine sulphate salt (Cat#P6777), GNF-5837 (Cat#SML0844), and ANA-12 (Cat#SML0209) were purchased from Sigma-Aldrich .2.N27 rat dopaminergic neural cell line harvested from E12 rat mesencephalic tissue and HT-22 mouse hippocampal cell line subcloned from the HT-4 cell line , U-251 human glioblastoma—a kind gift from Associate Professors Andrew Morokoff and Kate Drummond—, and HT-1080 human fibrosarcoma cells  were cultured in RPMI 1640 media (supplemented with 10% FBS and 1% penicillin and streptomycin). As previously described, primary cortical neurons were isolated from E14 C57BL/6J mice (RRID: IMSR_JAX:000664) . Upon is4 cells/well, while primary cortical neurons were 1 × 105 cells/well. Cells were then co-treated with tested compounds and ferroptosis inducers for 24 h (but tBH was for 4 h), and 20  μL of MTT (5  mg/mL) was added to each well and incubated for 2–4 h. The overlying media were aspirated from each well, and DMSO was added to the wells to dissolve formed formazan crystals in viable cells. The absorbance at 570 nm of the dissolved formazan demonstrated viable cells and was measured by a PowerWave XS microplate spectrophotometer , and cell viability was expressed as a percentage of control cells.The colourimetric MTT assay is routinely used to measure cell viability in the context of ferroptosis ,11,13. TABTS radical scavenging assay was used to evaluate the possible RTA properties of tested compounds in cell-free conditions. The assay was done according to the described protocol by Lee et al. (2015)  with theC11 BODIPY (581/591), a fluorophore that responds to lipid peroxidation with an increase in fluorescence emitted in the green range and a parallel decrease in fluorescence emitted in the red range, was employed to quantify lipid peroxides. After seeding cells per the viability assay, cells were co-treated with test compounds  for 24 h. Cells were washed once with PBS and then supplemented with PBS before measuring fluorescence at 565/600 nm (excitation/emission) for red fluorescence and 477/525 nm for green fluorescence using a CLARIOstar microplate reader . Lipid peroxidation was presented as the ratio of green to red C11 BODIPY fluorescence [We evaluated the possible RTA property of GNF-5837 in cell-free conditions by a fluorescence-based lipid peroxidation assay using the MDA Assay Kit  as previously reported [w/v) skimmed milk for 1 h at room temperature and then incubated overnight at 4 °C with primary antibodies against TrkB  and beta-actin , and then following incubation with the normal isotype-matched IgG-HRP conjugated antibodies (Dako) with a dilution ratio of 1:2000 for 1 h. Finally, immunoblots were visualised by a chemiluminescence reagent (Amersham ECL Start Western Blotting Detection Reagent) and imaged using a Fujifilm Luminescent Image Analyser LAS-3000 and then quantified by Image J software.Total protein was extracted from the cells by a RIPA lysis buffer containing 50 mM Tris, 150 mM NaCl, 0.1% SDS, 0.5% sodium deoxycholate, 1% Triton X-100 and cOmplete™, and an EDTA-free protease inhibitor cocktail . Protein was separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, which was then transferred to polyvinylidene difluoride membranes using the iBlot Gel Transfer Device (Invitrogen). The membranes were blocked in tris-buffered saline containing 0.1% Tween-20 (TBST) and additionally containing 5% (www.graphpad.com) were used to perform statistical analysis. Some test compounds were coloured; the operator and data assessment were not blinded, and samples were not randomised. At least 2–3 technical replicates were used to ensure the dependability of single values within each independent experiment.Microsoft Excel v16 and GraphPad Prism 9.1 software for windows . The corresponding fitted regression curve is shown on the data where an EC50 or IC50 is reported. One- or two-way ANOVA was used for all multiple comparisons to calculate statistical significance, and p < 0.05 was deemed statistically significant.Non-linear regression analysis with a variable slope model (four parameters) was employed to fit a logistic curve to dose–response data to determine ECWe found that several potent modulators of TrkB signalling, such as BDNF, K252a, and ANA-12, did not affect ferroptotic lethality in TrkB-expressing mature primary cortical neurons. BDNF mimetic 7,8-DHF, TrkB activator phenelzine, and inhibitor GNF-5837 showed TrkB-independent anti-ferroptotic activity, possibly acting as RTAs. Caution should be applied when interpreting the results of these compounds in prior and future studies since the potent RTA effect may confound the result. As we detected TrkB receptor expression only in mature cortical neurons, this study was limited to characterising the effect of TrkB signalling on RSL3-induced ferroptotic lethality. We do not exclude the possibility that TrkB modulators affect ferroptotic stress caused by cystine/glutamate transporter inhibitors such as erastin in TrkB-expressing cell lines.


E − EF = 0.2 and 0.65 eV from the pd-hybridization and controllable Dirac cone of graphene, respectively. In the parallel configuration, the transmission probability calculation showed a profile similar to that of the pristine graphene. High and colossal magnetoresistance ratios of 284% and 3100% were observed at E − EF = 0.65 eV and 0.2 eV, respectively. Furthermore, a magnetoresistance beyond 3100% was expected at E − EF = 0.65 eV when the width of the Ni(111) nanostructures on the nanometer scale was considered.In this study, we present a theoretical study on the in-plane conductance of graphene partially sandwiched between Ni(111) nanostructures with a width of ∼12.08 Å. In the sandwiched part, the gapped Dirac cone of the graphene was controlled using a pseudospin by changing the magnetic alignment of the Ni(111) nanostructures. Upon considering the antiparallel configuration of Ni(111) nanostructures, the transmission probability calculation of the in-plane conductance of graphene shows a gap-like transmission at  In this study, we present a theoretical study on the in-plane conductance of graphene partially sandwiched between Ni(111) nanostructures with a width of ∼12.08 Å. The equipotential of the C atoms in sublattices A and B of the graphene layer causes a Dirac cone energy band at zero energy. This Dirac cone energy band causes the electrons in graphene to behave peculiarly, having the same velocity and no inertia.2 Growing graphene on top of a transition metal substrate enables the sensitive tuning of the Dirac cone energy band. When graphene is placed on a metal substrate, hybridization occurs, breaking the chiral symmetry of graphene and creating a gapped Dirac cone.5 Another unique property of graphene is its magnetic response when grown on a ferromagnetic substrate.6–8 This induces a magnetic moment in graphene due to charge transfer and has an orientation opposite to that of the ferromagnetic substrate.8 Additionally, the weak spin–orbit coupling and long spin scattering length of graphene9 make it a prospective material for spintronic devices. Ni(111) surfaces are the most commonly used contacts for studying graphene-based spintronic devices due to their similar structures  and strong hybridization with graphene.6,7,10 Studies show that graphene has served as a bridge between two Ni electrodes11–13 because of its long spin relaxation lifetime9 and as a tunnel barrier in Ni/graphene/Ni magnetic tunnel junctions (MTJs).14–23 Although further results are expected, a new strategy for achieving low resistance and overcoming the absence of a bandgap is necessary to realize the application of graphene in spintronic devices.The extraordinary in-plane charge mobility of graphene24 When the magnetic moments of the upper and lower Ni(111) slabs have an antiparallel configuration (APC), the bandgap at the Dirac cone is open. However, the bandgap is closed in parallel configuration (PC). This unique characteristic is because the most stable arrangement of the Ni/graphene/Ni heterostructure occurs when Ni atoms of the upper and lower Ni(111) slabs at the interfaces hybridize with different graphene sublattices. In other words, Ni atoms from the lower Ni(111) slab hybridized with C atoms in sublattice A , and Ni atoms from the upper Ni(111) slab hybridized with C atoms in sublattice B . Although the C atoms of graphene bond with the Ni atoms, this special hybridization preserves the equipotential between sublattices A and B. Meanwhile, a magnetic moment is induced on the graphene layer by charge transfer from the Ni to C atoms. The induced magnetic moments of the CA and CB atoms depended on the magnetic alignment of the Ni(111) slabs. Moreover, the induced magnetic moments in APC and PC between the CA and CB atoms exhibit antiferromagnetic and ferromagnetic orders, respectively. This implies that the pseudospin between sublattices A and B can be controlled to preserve or break the chiral symmetry, thereby making the gap of the Dirac cone is also controllable. A controllable-gapped Dirac cone help realize a high in-plane magnetoresistance (MR) ratio for graphene.Previous studies showed that for a Ni/graphene/Ni heterostructure, the gapped Dirac cone of graphene can be controlled using the magnetic alignment of the Ni slabs.This study presents a theoretical study on the in-plane conductance and magnetoresistance of graphene partially sandwiched between Ni(111) nanostructures. Here, we investigate the effectiveness of a controllable Dirac cone on graphene conductance to realize a high MR ratio. For that purpose, we proposed a system consisting of Ni(111) nanostructures with a finite size and atomic-scale width of ∼12.08 Å sandwiched the middle part of graphene. Both the APC and PC states of the upper and lower Ni(111) structures are considered. First-principles quantum transport calculations, which coupled density functional theory (DFT) with the nonequilibrium Green's function, were performed. Our calculation results observed a high and colossal in-plane MR ratio of graphene about 284% and 3100%. A higher MR ratio beyond 3100% can be obtained when the width of the Ni(111) structures on a nanometer scale are considered.24 The finite size width of ∼12.08 Å for Ni(111) nanostructures was considered for understanding the effectiveness of the in-plane magnetoresistance of graphene created from the Ni/graphene/Ni magnetic junctions. Wider Ni(111) nanostructure, e.g., width in nanometer scale, is expected to exhibit high performance. Here, graphene was used as the buffer layer and electrodes in the calculation. We considered the same stacking arrangement used in the previous study, where Ni atoms at the interfaces of the lower and upper Ni(111) slabs hybridized with C atoms in sublattices A and B, respectively.24 Both APC and PC were considered for Ni(111) nanostructures.In this theoretical study, we considered Ni(111) nanostructures with three Ni atoms layer thickness and an atomic-scale width of ∼12.08 Å, as shown in 25 to obtain the structural equilibrium and spin-charge density properties of the proposed system. Furthermore, we described the electron–ion interaction using a revised Perdew–Burke–Ernzerhof functional for a densely packed solid surface 26 and ultrasoft pseudopotentials27 within the generalized gradient approximation (GGA). From our previous studies, the PBESol pseudopotential is essential to successfully achieve the interlayer distance between Ni slabs and graphene , which is consistent regardless the thickness of Ni slabs and agrees with experimental study.24,28,29 This interlayer distance at the interface is important because it determine the electronic state at the interface. The atomic positions were relaxed, with a total force tolerance of 0.001 eV Å−1. A 45 × 45 × 1 Monkhorst–Pack k-mesh was used for calculations. First-principles quantum transport calculations, which coupled DFT with the nonequilibrium Green's function, were performed using the Siesta and Transiesta packages30–34 to calculate the transport properties at a zero-bias voltage. The spin-dependent current through our proposed system was calculated using the Landauer–Buttiker given by:fL) is the right (left) moving electron injected from the left (right) lead in the form of the Fermi–Dirac function. μL(μR) denotes the chemical potentials of the left (right) electrodes. Since zero-bias voltage was considered, thus μL = μR = EF. In addition, the ballistic transmission T as a function of energy E is described with respect to the Green's function form asΓL(ΓR) is the coupling matrix of the left (right) electrode, GR(GA) is the retarded (advanced) Green's functions of the central region. Finally, the in-plane MR ratio for graphene was calculated as follows:A spin-polarized plane-wave-based DFT calculations were performed using the Quantum ESPRESSO package31 were used within GGA. A double-zeta plus polarization basis set35–37 was employed, and the temperature was set to 300 K. A perpendicular k-point of 1 × 901 with respect to the transmission direction was considered to obtain a good accuracy for the transmission probability.For the transmission probability calculation, the PBESol functional and Troullier–Martins pseudopotentialWe investigated the characteristics of the induced magnetic moment on graphene, which is sandwiched between the Ni(111) nanostructures. Particularly we focused on the boundaries between the bare and sandwiched graphene. Mapping of the spin-charge density, as shown in nAσ = nBσ with σ = ↑ or ↓. Meanwhile, the sandwiched graphene has an induced magnetic moment depending on the magnetic alignment of the Ni(111) nanostructures. For the Ni(111) nanostructures in APC state, A and CB atoms of the sandwiched graphene have an antiferromagnetic order. Thus,A and CB atoms of the sandwiched graphene have the same magnetic orientation and almost the same value , which is ∼0.04 μB. This means that the decrease in the magnetic moment amplitude along the boundary direction corresponds to the characteristics found in the finite size of the Ni nanostructures. From the structure of the system, this decrease is attributed to the coordination of Ni(111) nanostructures, which compresses their shape toward the center but maintains their bond with C atoms at the interfaces. An edged shape was formed on the Ni(111) nanostructures at the boundaries, which increases the lattice mismatch between the Ni layer at the interfaces and the graphene layer, and in turn, decreases the charge transfer from Ni atoms to C atoms. Thus, the reduced charge transfer from the Ni atoms to the C atoms at the interface decreases the induced magnetic moment on the C atoms. Since the lattice mismatch increases along the direction of the boundary, the induced magnetic moment also decreases along the same direction. However, the profile of the induced magnetic moment on sandwiched graphene is unique in PC. The induced magnetic moment initially decreases from the center of the sandwich to the boundaries. However, it then increases even higher than that of the center part before finally decreasing again near the boundaries. The magnetic moment of the C atoms in the center of the sandwiched graphene was approximately equal to the induced magnetic moment of the C atoms of the Ni/graphene/Ni MTJ, which was ∼0.022 μB. Furthermore, the decrease in the induced magnetic moment on the neighboring C atoms, which shifted from the center of the sandwich graphene to the boundary, corresponds to the increasing lattice mismatch, similar to the case of APC. Additionally, the amplitude of the magnetic moment on the C atoms increased even more than that in the center part at the boundaries due to the reduction in the antiferromagnetic configuration between sublattices A and B near the boundary. In the periodic system of Ni/graphene/Ni MTJ, we obtained higher amplitude of the induced magnetic moment of C atoms in APC is higher than that in PC24 since the carbon atoms of sublattices A and B in graphene had to have an antiferromagnetic (AFM) configuration because of the half-filled pz-orbital and Pauli's exclusion principle. This rule is often found in organic molecules in sp2-hybridization or magnetic alternant hydrocarbon systems.38 The contribution of the antiferromagnetic alignment between the hybridized C and Ni atoms near the boundaries is more dominant than that of the AFM alignment between the C atom sublattices A and B, leading to the increased induced magnetic moment. Finally, at the boundaries, the induced magnetic moment of the C atoms in the sandwiched part decreases again, indicating increased lattice mismatch.The magnetic moment characteristics of the CThese changes in the induced magnetic moment on sandwiched graphene affect the Dirac cone and mass-gapped Dirac-cone characteristics. For the Ni(111) nanostructures in the APC, the decreasing induced magnetic moment of the sandwiched graphene toward the boundary reduces the size of the mass-gapped Dirac cone. This implies that the Dirac cone mass-gapped is smaller at the boundaries of the sandwiched graphene than at the center. For Ni(111) nanostructures in the PC state, the changes in the induced magnetic moment affect the size of the Stoner gap between the spin majority and spin minority channels. These characteristics are discussed in detail in the next section.E − EF = 0.18–0.22 eV and 0.58–0.78 eV, with its lowest transmission probability at E − EF = 0.2 and 0.65 eV, respectively, to understand the origin of the gap-like transmission, local density of states (LDOS) and projected density of states (PDOS) calculations were performed on the Ni/graphene/Ni MTJ, which represents the sandwiched part of the proposed system. The LDOS of graphene, shown in E − EF = 0.2 eV corresponds to the gap-like transmission probability found at E − EF = 0.2 eV. This relation was observed in the spin majority and minority channel. This Dirac-cone-like DOS is originated from the hybridization between d2z-orbital of Ni atoms at the interface and pz-orbital of C atoms  nanostructures were in the APC state, as shown in  C atoms . The Dirdization .E − EF = 0.65 eV results from the opening mass-gapped Dirac cone of graphene  nanostructure does not optimize the induced magnetic moment on graphene and a constant value is not achieved, thereby resulting considerably high conductance at E − EF = 0.65 eV. However, this also implies that, when a width of Ni(111) nanostructures is considered in the nanometer scale, the transmission probability at E − EF = 0.65 eV will be as low as at E − EF = 0.2 eV.The gap-like transmission probability at graphene . HoweverE − EF = 0.2 and 0.65 eV, respectively nanostructures in APC and PC states, a high and colossal in-plane MR ratio of up to 3100% and 284% was observed at pectively. ApplyinMR ratio . InteresA and CB of the sandwiched graphene.In this study, we investigated the in-plane conductance of graphene, where the Ni(111) nanostructures with a width of ∼12.08 Å is sandwiched in the center of the graphene. Both the APC and PC states of the Ni(111) nanostructures were considered. The induced magnetic moment was observed on the sandwiched graphene and could be controlled using the magnetic alignment of the Ni(111) nanostructures. When APC (PC) state is considered, we observed that the carbon atoms of sublattices A and B of the sandwiched graphene had an antiferromagnetic (ferromagnetic) order. Both spin configurations lead to a controllable mass-gapped Dirac cone in the sandwiched graphene. The mass-gapped Dirac cone is open (closed) for APC (PC) state due to the modulated (equi-) potential between the CWhen the Ni(111) nanostructures were in the PC state, the transmission probability of the proposed system produces a profile similar to that of the pristine graphene. Furthermore, a slight increase in the total transmission probability was observed from spin-up electrons that transmit through graphene and the Ni(111) nanostructures. Thus, spin-up electrons have a higher transmission probability than the spin-down electrons.E − EF = 0.18–0.22 eV and 0.58–0.78 eV with the lowest transmission probability at E − EF = 0.2 and 0.65 eV, respectively. The gap-like transmission probability at E − EF = 0.2 eV comes from the Dirac-cone-like DOS shown in the local density of sandwiched graphene due to the hybridization property between the d2z-orbital of Ni atoms at the interface and pz-orbital of C atoms. On the other hand, the gap-like transmission probability at E − EF = 0.65 eV comes from the opening mass-gapped Dirac cone of graphene. However, the gap-like transmission probability was smaller than that found in the LDOS of graphene in Ni/graphene/Ni MTJ. This is because the induced magnetic moment decayed from the center part of the sandwiched graphene toward the boundary, leading to a parabolic shape for the transmission probability gap.However, for the Ni (111) nanostructures in the APC state, a unique gap-like transmission probability was observed from E − EF = 0.2 and 0.65 eV. By applying a gate voltage, the Fermi energy can be controlled resulting in a colossal in-plane MR ratio. Furthermore, by increasing the width of the Ni(111) nanostructure to the nanometer scale, a colossal MR ratio > 3100% can be expected because the gap-like transmission is nearly zero at E − EF = 0.65 eV in the APC state but having higher the transmission probability than that at E − EF = 0.2 eV in the PC state.Finally, high and colossal in-plane MR ratios of up to 3100% and 284% were observed at Conceptualization was performed by Y. W., K. K., H. H., and G. K. S. performed computer simulations of the atomic layered systems and M. A. M. conducted the theory of atomic layered materials. Y. W. determined the equilibrium structure of the proposed system and performed spin-charge density mapping and transmission probability analysis on the proposed system. YW wrote the original draft of the manuscript. All the authors have reviewed the manuscript. The manuscript was written through the contributions of all authors. All the authors approved the final version of the manuscript.There are no conflicts of interest to declare.


Graphene is a promising material that may be potentially used in biomedical applications, mainly for drug delivery applications. In our study, we propose an inexpensive 3D graphene preparation method by wet chemical exfoliation. The morphology of the graphene was studied by SEM and HRTEM. Moreover, the volumetric elemental composition  of the materials was analyzed, and Raman spectra of prepared graphene samples were obtained. X-ray photoelectron spectroscopy, relevant isotherms, and specific surface area were measured. Survey spectra and micropore volume calculations were made. In addition, the antioxidant activity and hemolysis rate in contact with blood were determined. Activity against free radicals of graphene samples before and after thermal modification was tested using the DPPH method. The RSA of the material increased after graphene modification, which suggests that antioxidant properties were improved. All tested graphene samples caused hemolysis in the range of 0.28–0.64%. The results showed that all tested 3D graphene samples might be classified as nonhemolytic. Nanomedicine is a new generation of medicine that involves the application of nanoscaled materials. Among them, graphene is an emerging material due to the variety of its properties. In most research, graphene has been studied in electrochemical applications as an electrode material for constructing supercapacitors, photovoltaic cells, and metal–air batteries ,3,4,5,6.By definition, graphene is a paternal 2D material; however, its 3D structuring is possible and may deliver a new sort of material comprising graphene’s unique properties  with ones typically attributed to standard 3D materials (porosity and enhanced surface area) ,13,14.The 2D nature of pristine graphene hinders its applicability to the immobilization of large molecules  and microscopic objects such as cells or bacteria ,16. SuchGraphene has also been studied as an additive to polymeric matrixes. Such hybrid materials have shown improved mechanical properties . GraphenHowever, all modifications should be defined as safe and non-toxic. The aim of the proposed study was to determine graphene properties in terms of its applicability as a material for living-cell-bearing supports of advanced 3D architecture. The scheme of the method used by the authors is shown in In such a case, non-destructive activity towards basic body fluids such as blood and lymph is absolutely essential since such cell-containing structures will stay in permanent contact with fluids. Moreover, the antioxidant properties of graphene-based materials should be tested, since this feature is a part of widely understood blood compatibility. In this work, the so-far-achieved goals in the 3D structuring of graphene flakes will be exploited to receive 3D graphene derivatives, the blood compatibility of which is still unknown. We assume that blood compatibility should be investigated since our 3D structuring protocol involves the addition of a hard template, a cationic surfactant, and other chemical reagents, which have to be used to achieve advanced pore structure. The up-to-date collected knowledge and skill by authors in the area of graphene exfoliation and subsequent 3D structuring has been assumed as a starting point for the design of 3D graphene derivatives that are safe in contact with blood.Graphene and other carbon materials need to be characterized by a set of widely approved experimental methods, as in this study. Such features as surface area, pore structure, and chemical composition are crucial for any carbon-based material apart from biological activity.2CO3 nanocrystals precipitate among exfoliated graphene flakes upon drying the reaction mixture. Thus, the template particles were removed by HCl etching and washing with distilled water. N2 sorption analysis showed that the specific surface area decreased (330–391 m2/g) below the value determined for the used paternal graphene nanoplatelets (750 m2/g). In parallel, changes of the pore structure became visible. The total pore volume decreased in all samples from 0.999 (GF-750) to 0.220 cm3/g (GF_Na_600). Surprisingly, the contribution of the mesopore volume Vme to the total pore volume Vt increased from 36% to 79%. It is notable that for three of four investigated samples the share of mesopores is close to 50% or much higher. The presence of mesopores (average pore diameter from 2 to 50 nm) is significant for applications involving a liquid environment where adsorption/desorption proceeds .The elemental composition and surface parameters for the obtained samples of porous 3D graphene are given in Additionally, the morphology details of representative samples are shown in the HRTEM images . Figure In the case of carbon-based materials, the surface elemental composition may substantially differ from the bulk elemental content. In general, carbon is a reactive element, and surface atoms may come into reaction with gases present in the atmosphere. In particular, oxygen is supposed to yield diversified surface-oxygen-based species. Therefore, two methods need to be applied to determine elemental composition: elemental combustion analysis  and XPS .The results of combustion elemental analysis only allowed the bulk content of three elements to be determined: C, N, and H, while the specific chemical environment of the heteroatoms embedded in the carbon matrix remains unknown. Therefore, obtained samples were additionally supported by X-ray photoelectron spectroscopy (XPS) investigations. A sample with the most promising biological properties was selected for the XPS study based on DPPH and blood compatibility. The XPS spectra of the representative GF_Na_800 sample were determined and are demonstrated in 3 hybridized atoms (band C 1s at binding energy 285.0 eV), which is characteristic of graphene materials. The C 1s spectra of the GF_Na_800 sample are composed of four peaks corresponding to C-C bond (sp3) peak at 285 eV  specimen is the absorbance of solution in contact with tested samples;[OD] negative is the absorbance of blood in physiological saline;[OD] positive is the absorbance of blood in water.For the study of compatibility of the graphene samples with blood, anticoagulated sheep blood (0.2 mL) was added to physiological saline solution (10 mL) which contained 1 g of each sample (n = 3) according to ASTM Hemolysis (Direct Contact and Extract Methods) GLP Report. Two control samples with the addition of fresh blood were prepared: positive (in water) and negative . The mixture was incubated  and the suspension was centrifuged . The absorbance was measured spectrophotometrically at 540 nm by using the Multiscan FC  . FinallyThe applied manufacturing protocol, despite some chemical reagents used as hard templates and cationic surfactants, delivers a blood-compatible porous material potentially applicable for further living-cell-involved manipulations. The antioxidant activity of the material increased after graphene modification. The maximum RSA = 89% was noticed after graphene treatment at 800 °C. Moreover, the increase in the temperature in the preparation process results in an increase in the hemolysis rate. The structural properties indicate a high quality of obtained porous graphene structures with a well-developed surface area and pore structure, which is essential for living cell immobilization. We have proven that the manufacturing protocol is relatively environmentally friendly and low-cost. These aspects of the performed study will be continued in further research.


For EGr/GC, the oxidation peak was higher and appeared at lower potential (+1.12 V) compared with that of bare GC (+1.35 V). The linear range for AZT obtained with the EGr/GC electrode was very wide, 10−8–10−5 M, the sensitivity was 0.68 A/M, and the detection limit was 3.03 × 10−9 M. It is important to mention that the sensitivity of EGr/GC was three times higher than that of bare GC (0.23 A/M), proving the advantages of using graphene-modified electrodes in the electrochemical detection of AZT.An electrochemical cell containing two graphite rods was filled with the appropriate electrolyte (0.2 M ammonia + 0.2 M ammonium sulphate) and connected to the exfoliation system to synthesize graphene (EGr). A bias of 7 V was applied between the anode and cathode for 3 h. After synthesis, the morphology and structure of the sample was characterized by SEM, XRD, and FTIR techniques. The material was deposited onto the surface of a glassy carbon (GC) electrode (EGr/GC) and employed for the electrochemical detection of azithromycin (AZT). The DPV signals recorded in pH 5 acetate containing 6 × 10 For many years, infectious diseases have represented a difficult, persistent, and on-going public health challenge. However, by the mid-1900s, following the introduction of antibiotics, the mortality rate of infectious illnesses had significantly decreased , and theAzithromycin (AZT), an azalide—a subclass of macrolide-type antibiotics, is a second-generation broad-spectrum antibiotic with a long half-life and a high tissue penetration degree , primari2O4 [However, most of the reported methods present serious drawbacks since the microbiological approaches need long incubation periods and are affected by limited detection ability and poor accuracy ,25, whil2O4 ; aniline2O4 ; renewab2O4 ; and ion2O4 . Among t2O4 ,43.With several surprising features in its two-dimensional structure , graphenIn this work, we present a simple approach for modifying a glassy carbon electrode with graphene obtained by a simple electrochemical method, without the use of organic solvents. The modified electrode exhibits improved characteristics both in terms of sensitivity and the detection limit of AZT, in comparison with bare GC. In addition, we used the standard addition method for the quantification of AZT in spiked samples, demonstrating excellent results.High purity (99.995%) graphite rods  were purchased from Sigma-Aldrich  and were employed during electrochemical exfoliation. Ammonium sulphate was bought from Reactivul Bucuresti , while the ammonia solution (25%) was purchased from POCH SA . Azithromycin (AZT) was purchased from HiMedia Laboratories Pvt. Limited , uric acid , dopamine hydrochloride , and dimethylformamide (DMF) were purchased from Alfa-Aesar , while L-tyrosine (Tyr) was purchased from Fluka BioChemika . Glacial acetic acid (99.5%) was purchased from CHEMICAL COMPANY  and sodium acetate was purchased from Reactivul Bucuresti . Sodium dihydrogen phosphate (99.7%) and di-sodium hydrogen phosphate anhydrous (100%) were purchased from VWR Chemicals . Acetate buffer was employed for the preparation of the solutions with pH 3.6, 4.4, and 5. Phosphate buffer was employed for the preparation of the solutions with pH 6 and 7.−2 M AZT solution) was added, so the final concentration of the drug was 2 × 10−7 M AZT. This was denoted as the real concentration  of the drug. Next, three equal volumes (50 µL) from 10−4 M AZT stock solution (in ethanol) were added to the beaker under continuous stirring and the current increase was read after each addition . The current step was plotted versus the concentration, allowing us to determine the AZT (Cx) in the analyzed drug, resulting in Cx = 1.76 × 10−7 M, while Creal = 2 × 10−7 M. The recovery was determined as the Cx/Creal ratio (88.45%). It is important to mention that the recovery data obtained for several drug solutions of different concentrations ranged from 80 to 88.45%, indicating that some of the interfering species may interact with the electrode surface. According to the drug leaflet, the powder also contains sugar, xanthan gum, hydroxypropyl cellulose, anhydrous trisodium phosphate, anhydrous colloidal silicon dioxide, aspartame (E 951), caramel cream flavor, and titanium dioxide (E 171). For azithromycin determination using the standard addition method, the following procedure was applied. In 5 mL of acetate buffer solution (pH 5), a proper amount (0.38 µL) from the commercially available pharmaceutical drug , equipped with a cold field emission gun (CSEG). X-ray powder diffraction (XRD) was employed for the structural investigations of the graphene sample. The sample was dispersed in DMF (0.2 mg/mL) and then deposited onto the surface of an amorphous quartz substrate. A D8 Advance Diffractometer , 40 kV, 0.5 mA, equipped with a LYNXEXE detector (λ = 1.5406 Å) was employed.−1 spectral domain (4 cm−1 resolution). About 0.3 mg of graphene was mixed with KBr powder and pressed in a thin pellet, before recording the spectrum. The FTIR spectrum of graphene was recorded with a JASCO 6100 FTIR spectrometer , within a 4000–400 cmA Christ-Alpha 1–4 LSC freeze dryer equipment  was employed for drying the graphene sample after electrochemical exfoliation of the graphite rods.For the electrochemical measurements  and amperometry), the cell containing three electrodes was coupled with a Potentiostat/Galvanostat Instrument PGSTAT-302N . The GC (3 mm diameter) or the EGr/GC electrode was employed as a working electrode, together with a Ag/AgCl reference (3 M KCl) and a large foil platinum counter electrode. The DPV measurements were generally recorded from 0.5 to +1.5 V vs. Ag/AgCl, at a 10 mV/s scanning rate , while the amperometric measurements were recorded at +1.12 V (for the EGr/GC electrode) and +1.35 V (for the bare GC electrode). An electrochemical cell containing two graphite rods  was filled with the appropriate electrolyte (0.2 M ammonia + 0.2 M ammonium sulphate) and connected to the exfoliation system . The pulse generator allowed us to set the time parameters of the current pulses, such as the duration (0.8 s) and the pause between two pulses (0.2 s) . During N,N-dimethylformamide (DMF) was chosen as the organic solvent for the dispersion of the graphene sample (2 mg/mL). DMF has a higher boiling point (153 °C) in comparison with that of ethanol (78.37 °C) or distilled water (100 °C), which means that it evaporates slower at room temperature. Consequently, the graphene flakes from DMF solution have a longer time to interact by π–π stacking with the electrode surface, leading to the formation of a very stable layer on top of the GC electrode. A total of 10 µL from the graphene dispersion in DMF, previously homogenized with an ultrasonic device (SONICS Vibra-Cell), was deposited by the drop-casting method onto the GC electrode and dried at room temperature for 24 h. After that, the modified electrode (EGr/GC) was used for AZT electrochemical detection and quantification.The structural characteristics of the graphene sample were next investigated by the XRD technique. The pattern of the sample can be seen in −1 can be assigned to the O–H stretching vibrations from the adsorbed water molecules, while the 1383 cm−1 band is assigned to the C–O stretching vibrations of the functional groups attached to graphene. The large shoulder at around 3000 cm−1 may be attributed to the aromatic C–H stretching bands, which are weak-to-moderate bands. The other two important bands are the aromatic ring stretching vibrations centred at around 1638 and 1577 cm−1, which generally appear as a pair of band structures. These bands are characteristic of the vibration modes of the sp2-hybridized carbon atoms (C=C). Next, more information about the vibration characteristics of the functional groups attached to the graphene surface was obtained by the FTIR technique. The spectrum of the sample embedded in the KBr pellet is presented in −1, the graphite (G) band at 1582 cm−1, and the 2D bands at 2708 cm−1, generated by the in-plane vibrations [D/IG ratio [D/IG ratio is inversely correlated with the defect-free domain or the in-plane crystallite size (La):a was determined to be 17.91 nm. This is a large value, so we can assume that the majority of the defects are located at graphene edges. This is in excellent agreement with the SEM/TEM micrographs, which revealed that the basal planes of graphenes are generally smooth and defect-free. Raman analysis is useful for determining the structural properties of graphitic materials. The defect (D) band at 1355 cmbrations , shear mbrations , and thebrations , are thebrations , indicatbrations . HoweverIG ratio , which wIG ratio , the ID/−5 M). The DPV technique was employed, and the selected pH range was 3.6–7.0. Since the pKa of azithromycin is 7.34 [a. As can be seen in p) is well-defined above pH 4.4 and has a maximum value at pH 5. At pH value close to pKa, the peak current starts to decrease .According to the literature , in solup, with the natural logarithm of the scan rate, lnυ, for irreversible reactions (linear sweep voltammetry).a is the charge transfer coefficient, sk, the standard rate constant of the surface reaction, n is the number of electrons involved in the reaction, and E0′ is the formal potential.In order to determine the number of electrons involved in the oxidation reaction, the Laviron Equation (2) was employed . The equ−5 M azithromycin by varying the scan rate from 2 to 100 mV/s. Using the Ep vs. lnυ plot, we determined nαa from the corresponding slope  solution containing 6 × 10ng slope a. The obp and pH was obtained, following the equation: Ep = 1.42 − 0.052 × pH (r2 = 0.972). Since we determined that the number of electrons involved in the redox process is 1, it is reasonable to assume that the number of hydrogen ions taking part in the electrode reaction is also 1.The pH effect on the oxidation peak potential of azithromycin was also investigated b. The pe−5 M AZT revealed significant differences between the two electrodes. For EGr/GC, the oxidation peak is higher and appears at lower potential (+1.12 V) compared with that of the bare GC electrode (+1.35 V). The increased sensitivity of EGr/GC cannot be attributed only to its high electrochemical roughness factor, which was determined to be 1.46 . Other factors are the enhanced electron transfer rate at the edges of graphene sheets and the hydrophobic interaction between AZT and graphene, which may help with the orientation of N3 amine group towards graphene, favouring its oxidation. The electrocatalytic properties of the synthesized material towards AZT oxidation are now discussed in comparison with those of the bare GC electrode . Hence, −6–6 × 10−5 M) in pH 5 acetate buffer, using the DPV technique. The corresponding signals are plotted in −5 M concentration. The linear range for AZT was 10−6–3 × 10−5 M, the sensitivity was 0.043 A/M, and the detection limit was 3.03 × 10−7 M. Further analysis of AZT was investigated by recording the AZT signals at various concentrations , proving the advantages of using graphene-modified electrodes in the electrochemical detection of AZT. Significantly better results were obtained by employing the amperometric technique , as can be seen in −5 M AZT  and for a mixture of analytes, DA + UA + Tyr + AZT (10−5 M each), are presented. All the analytes appear at well-defined oxidation potentials and their mixture led to the slight increase in the AZT oxidation peak and potential, indicating a weak influence of the interfering species.Next, the selectivity of the EGr/GC electrode was evaluated in the presence of various interfering biomolecules such as dopamine (DA), uric acid (UA), and tyrosine (Tyr). In −2 M; 0.38 µL) and the stock solution  was read and plotted versus the concentration, allowing us to determine the concentration of the drug, Cx . It is important to mention that the recovery data obtained for the three drug solutions ranged from 80 to 88.45%, indicating that some of the interfering species may interact with the electrode surface. Since the EGr/GC electrode proved to have a good selectivity, it was additionally tested for AZT quantitative analysis in pharmaceutical drug solution, using the standard addition method a,b. The −8–10−5) for AZT, with excellent sensitivity (0.68 A/M); and the detection limit was 3.03 × 10−9 M  was prepared by the electrochemical exfoliation of graphite rods and characterized by advanced techniques  to obtain information about its morphology and structure. The SEM micrographs revealed that some of the graphene flakes are large  and have a smooth surface, while others are small  and exhibit a wrinkled appearance. The flakes are also thin and randomly oriented, generating a highly porous layer which is beneficial in electrochemical investigations due to the increase in the active area of the modified electrode. The XRD technique evidenced that the sample contains few-layer graphene (95%) and multilayer graphene (5%), while the FTIR technique allowed the identification of the oxygen-containing groups attached to graphene. The graphene-modified electrode (EGr/GC) was next used for azithromycin (AZT) electrochemical detection and quantification. Excellent results were obtained by employing the amperometric technique .


In this work, the adsorption energy and the electronic properties of a graphene/WS2 structure were calculated by first-principles before and after adsorption of NH3. The calculation results indicate that the bandgap of the material was appreciably reduced after NH3 was adsorbed. In addition, a graphene/WS2 gas sensor was prepared. The response of the sensor to NH3 at a concentration of 100 ppm was 2.42% and 1.73% at 30 °C and 60 °C, respectively. Combining simulation with experiment, it is feasible to use graphene composite WS2 to detect NH3, which provides a new idea for applications of graphene and other composite materials in gas sensing.Two-dimensional materials have outstanding application prospects in gas sensing. By constructing composite structures of various gas-sensitive materials, more-efficient and sensitive gas sensors can be further developed. After graphene is compounded with WS In recent years, in-depth research on two-dimensional materials has promoted further development of gas sensor technology, and has enabled gas sensors to move toward high sensitivity, stability, and reliability, as well as a fast response and recovery rate ,2,3. Amo2, MoTe2, and other materials have advantages of, e.g., high sensitivity and function at room temperature [However, because of limitations imparted by the electrical properties of graphene, the performance of gas sensors prepared by using graphene has thus far failed to meet theoretical expectations. Accordingly, researchers have prepared graphene-based composite materials , metal oxides, and functional polymers on the surface of graphene). Rapid transfer of charges at the interface of the composite material can improve the sensing performance ,6,7. In perature ,9.2, a dense layered stacked structure readily forms in the process of forming a charged network inside the material. This stacked structure is not conducive to the contact between the nanosheets and gas molecules [2 with graphene to prepare a graphene/WS2 composite structure. The large specific surface area of graphene can absorb more gas molecules, whereas WS2 can output a higher response. Complementing the advantages of the two materials will facilitate gas detection [As a representative material in TDMs, during electrical testing of WSolecules . Alternaetection ,12.3 based on a graphene/WS2 composite structure. The electronic energy band structures of WS2, graphene/WS2, and graphene/WS2/NH3 were calculated by using first-principles, and the bandgap changes were compared and analyzed. Moreover, a graphene/WS2 composite gas sensor was prepared, and the response sensitivity of the device to NH3 at various temperatures was discussed. A combination of theoretical simulation and experiment helps to better understand detection of NH3 by the graphene/WS2 composite structure.This work discusses adsorption of NH2 composite structure; its properties were studied by using CASTEP based on density functional theory [−5 and 1 × 10−1 eV/nm, respectively. The corresponding maximum stress displacement did not exceed 0.02 GPa and 5 × 10−4 nm, respectively. The BFGS algorithm was used for geometric optimization [The research goal is adsorption of ammonia gas by using a graphene/WSl theory ,14. To el theory . The Brimization . Figure 2 substrate by using wet transfer technology. A comb-shaped electrode was deposited onto the substrate. The space of the electrode was 200 μm. WS2 nanosheets were prepared by a one-step hydrothermal reaction. Tungsten chloride  and 25 mmol of thioacetamide (CH3CSNH2) were dissolved in 35 mL of deionized water and stirred for 40 min; then, the solution was transferred to a Teflon-lined stainless steel autoclave, held at a temperature of up to 220 °C, and kept at this temperature for 24 h. After cooling, the reaction products were washed and freeze-dried. Then, WS2 was ultrasonically dispersed in deionized water. The concentration of the WS2 suspension was 10 mg/mL. A 1.5-µL pipette was used to apply one to two drops of WS2 suspension onto the graphene above the substrate. After drying at room temperature in air, it was aged at 60 °C for 2 h to achieve stability. After the device was prepared, a WS-30B system was used to test the response characteristics of the graphene/WS2 composite gas sensor in a 100 ppm NH3 atmosphere. The temperature, humidity and gas concentration are automatically controlled by the gas sensing test bench, and the atmosphere of the test chamber is controlled by software. To reduce the influence of humidity in the experiment, the humidity of the test system was controlled to 25%, and the test temperatures were 30 °C and 60 °C. Before the test, background gas  was introduced, and then NH3 was introduced for testing and signal acquisition.The graphene grown by CVD was transferred onto an Si/SiO2 directly affect the electron transport properties inside the material. Therefore, the energy band structure of the composite material before and after the adsorption of gas was calculated. The bandgap of graphene is zero, and thus in this work only the energy band of WS2 and graphene/WS2 was calculated. 2. 2 was 1.945 eV. Both the bottom of the conduction band and the top of the valence band are located at point G, indicating that WS2 is a direct bandgap. This value is similar to previous results [The interfacial interactions of graphene/WS results ,18, whic2 before and after adsorption of NH3. When graphene was compounded with WS2, the bandgap of the composite structure changed significantly. The top of the valence band was at the high symmetry point G, and the bottom of the conduction band was at point G. The composite structure transformed into an indirect bandgap; the bandgap value was 1.187 eV. Concomitantly, the independent energy band structure of WS2 was largely retained when the two materials were composited. The conduction band shifted to the Fermi level with a low bias, such as in n-type doping. This is attributable to the electrons provided by the graphene transition to the conduction band. The energy height of the electrons that left the bottom of the conduction band was reduced. When the composite structure adsorbed NH3 molecules, its energy band structure did not change significantly compared with the structure of not-yet-adsorbed gas; but the bandgap value decreased to 1.246 eV, and the conduction band continued to move toward the Fermi level. Thus, after NH3 was adsorbed, electrons more readily migrated from the top of the valence band to the low conduction band, and the conductivity of the composite material was significantly improved [improved .2 before and after adsorption of NH3. After adsorption of NH3, the total density of states shifted slightly to the left, which indicates that charge transfer was facilitated [3 changed the strong hybridization and bonding between the atomic orbitals, which changed the charge transfer. In addition, under this simulation system, the adsorption energy Ead of graphene/WS2 for NH3 can be calculated as follows [ilitated . Concomi follows ,22.Ead 3 adsorption was −94,137.75 eV, whereas the total energy of the composite material without adsorbed gas ad of graphene/WS2 to NH3 was calculated as −1.25 eV. This value indicates that the composite material can readily achieve NH3 adsorption.In this simulation system, the total energy 2, the electron transport inside the material changed. Moreover, the composite material readily adsorbed NH3 and the bandgap of the adsorbed material was reduced. This indicates that the composite of graphene and WS2 will facilitate construction of a sensor for detecting NH3.Through analysis of the simulation results, it was evident that after graphene was compounded with WS2 prepared by the hydrothermal method. 2 was composed of agglomerated flocculent particles. After partial magnification in 2 nanosheets were found at the edge of the WS2 block and presented a loose structure, indicating the high specific surface area, which was beneficial to NH3 adsorption and improving the gas sensitivity. 2, and the XRD pattern is consistent with pure hexagonal WS2 (JPCDS No. 084-1398). The reflections at 14.22°, 34.04°, and 56.78° (corresponding to the (002), (100), and (110) planes, respectively) confirm the presence of the hexagonal phase. The sharp peaks indicate the crystallinity of the as-prepared sample. Some peaks were evident, along with slight rightward shifts of the peak positions and broadening, which indicates that there was some residual compressive stress on the surface of the WS2 nanosheets after freeze-drying.2 gas sensor when exposed to 100-ppm NH3 at 30 °C with 25% humidity. In accordance with the NH3 introduction time, the resistance of the gas sensor first increased and then decreased. This trend indicates that the device adsorbed gas molecules in an NH3 atmosphere, and detected NH3. As the concentration of gas absorbed onto the surface of the graphene and WS2 increased, charge transfer occurred between the gas molecules and the composite material. The type and concentration of carriers inside the composite material changed, which eventually led to the change in sensor resistance. This change corresponds to the gas response of the device [e device .The response time (recovery time) was defined as the time required to reach 90% of the change in sensor resistance upon exposure to the target gas (air). 2 sheet failed to desorb, which reduced the resistance of the WS2, improved the barrier between graphene and WS2, accelerated the transfer between electrons, and changed the overall electrical performance of the devices [A single response/recovery curve can indicate the response and recovery time of the device, but the overall performance of the device must be measured over a long period of time. During the entire experiment, the humidity was set to be 25% and the temperature was 30 °C, which eliminated the interference that would have been caused by temperature and humidity changes.  devices . Temperature corresponds to the diffusion rate of gas molecules. The detection performance of the sensor differed at different temperatures. Therefore, after adjusting the temperature to 60 °C, one can test the sensor again. Other experimental conditions are the same as those at 30 °C.2 gas sensor when the NH3 concentration was 100 ppm and temperature was 60 °C. Similarly to the test result at 30 °C, the sensor still detected NH3 molecules at 60 °C. At 60 °C, the response time of the gas sensor was 300 s and the recovery time was 600 s. The response time was the same as that at 30 °C, but the recovery time was significantly shortened. This is because the increase in temperature aggravated the movement of NH3 molecules. Molecules that might be attached to the gas-sensitive material at 30 °C will also accelerate desorption as the temperature increases. In accordance with the various means by which gas molecules are adsorbed on the surface of the material, the means of gas adsorption can be divided into physical adsorption and chemical adsorption. Physical adsorption mainly depends on the interaction forces between molecules, whereas chemical adsorption depends on the formation of chemical covalent bonds between gas molecules and the surface of the composite material. In general, physical adsorption precedes chemical adsorption [3 molecules mostly remain on the surface of composite materials by physical adsorption.sorption . The tem3 concentration was 100 ppm and the temperature was 60 °C. The device responded and recovered many times within more than 1 h of test time.3 such that NH3 underwent partial chemical adsorption concomitantly with physical adsorption. Over the course of desorption, a temperature of 60 °C is insufficient to destroy the stable chemical covalent bond. Chemical adsorption of NH3 on the surface of the material prevented the device from responding in the next cycle. As a result, there was a smooth region below the curve. 3 molecules that were not desorbed gathered on the surface of the composite materials. The aggregated molecules hindered the desorption and slowed the recovery rate. Therefore, the recovery time exhibited a gradually increasing trend [The device can maintain the excellent response after passing many cycle tests. Due to multiple recovery processes, many NHng trend . 0 − Rt|)/R0 × 100%. In the aforementioned formula, R0 is the initial resistance value of the gas sensor in air and Rt is the resistance value of the gas sensor after adsorbing NH3 molecules. At temperatures of 30 °C and 60 °C, the response of the sensor was 2.42% and 1.73%, respectively. The response of this type of device was lower than that in previous studies, but exhibited a faster response time (The response can intuitively reflect the performance of the device. The response (S) of the sensor was defined as (|Rnse time .2 is not obvious and there is stacking, which cannot provide sites for more gas molecules. The electron migration ability is reduced, and the composite material fails to assume the role of a bridge for electron transport.The low response mainly corresponds to the method used to prepare the device. Especially after one transfers the graphene to the electrode, the graphene will break, curl, and leave contaminants. In addition, the layered structure of WS3 by graphene/WS2 composites through simulation. After adsorption of NH3, the bandgap value of the material was significantly reduced, and the adsorption energy was calculated: 1.25 eV. The simulation results indicate that the use of graphene composite WS2 to detect NH3 is feasible under certain conditions. A graphene/WS2 gas sensor was also prepared, which realized detection of NH3 and verified the assumptions of the simulation results. At 30 °C and 60 °C, the response to 100-ppm NH3 was 2.42% and 1.73%, respectively. This research provides new ideas for applications of graphene and other composite materials in gas sensing.This work analyzed adsorption of NH