Hipposideros armiger: mass = 55 g, span = 51 cm). The bat was observed to decrease its flight velocity and gain approximately 20 cm of altitude entering the U-turn. By lowering its velocity from 2.0 m/s to 0.5 m/s, the centripetal force requirement to execute a tight turn was substantially reduced. Centripetal force was generated by tilting the lift force vector laterally through banking. During the initiation of the U-turn, the bank angle increased from 20 degrees to 40 degrees. During the initiation and persisting throughout the U-turn, the flap amplitude of the right wing (inside of the turn) increased relative to the left wing. In addition, the right wing moved more laterally closer to the centerline of the body during the end of the downstroke and the beginning of the upstroke compared to the left wing. Reorientation of the body into the turn happened prior to a change in the flight path of the bat. Once the bat entered the U-turn and the bank angle increased, the change in flight path of the bat began to change rapidly as the bat negotiated the apex of the turn. During this phase of the turn, the minimum radius of curvature of the bat was 5.5 cm. During the egress of the turn, the bat accelerated and expended stored potential energy by descending. The cycle averaged total power expenditure by the bat during the six wingbeat cycle U-turn maneuver was 0.51 W which was approximately 40% above the power expenditure calculated for a nominally straight flight by the same bat. Future work on the topic of bat maneuverability may investigate a broader array of maneuvering flights characterizing the commonalities and differences across flights. In addition, the interplay between aerodynamic moments and inertial moments are of interest in order to more robustly characterize maneuvering mechanisms.Bats possess wings comprised of a flexible membrane and a jointed skeletal structure allowing them to execute complex flight maneuvers such as rapid tight turns. The extent of a bat’s tight turning capability can be explored by analyzing a 180-degree U-turn. Prior studies have investigated more subtle flight maneuvers, but the kinematic and aerodynamic mechanisms of a U-turn have not been characterized. In this work, we use 3D optical motion capture and aerodynamic simulations to investigate a U-turn maneuver executed by a great roundleaf bat ( Of the three animal groups capable of powered flight—insects, birds, and bats—bats uniquely possess highly flexible wings composed of a jointed skeletal structure and a thin compliant skin membrane with embedded muscles. This wing morphology allows a bat to perform complex flight maneuvers which are critical to navigating cluttered environments and capturing prey. Three fundamental factors in understanding the maneuvering flight of bats are the shape and structure of their wings (morphology), the motion of the wings during flight (kinematics), and the interaction of the wings with the surrounding air (aerodynamics).Early work on characterizing the maneuverability of bats focused on wing morphology. In 1987, Norberg and Rayner investigated the relationship between bat wing morphology and flight capabilities such as maneuverability . This stAn early description of the turning radius of a flying animal as a function of mass, wing area, and bank angle was provided by Pennycuick . HoweverRhinolophus ferrumequinum, R. hipposideros, Plecotus auritus, Myotis mystacinus, M. daubentoni, and Pipistrellus pipistrellus )Over the six wingbeat cycles, close agreement is seen in the global x and y-directions. The force in the z-direction is slightly under predicted but falls within a reasonable margin of error. Overlaid on the figure is an envelope containing the range of predicted z-position admitting to a possible ±10% over or under prediction of force. Due to the time integration, a constant force error accumulates substantially in the predicted position. Therefore, it is more appropriate to evaluate the predicted position relative to the envelop instead of the absolute deviation. Exact estimation of aerodynamic force is challenging in live flying animals and the ±10% envelop represents a reasonable margin of error based on what is typically achievable using a range of techniques .In order to characterize the progress of the maneuver over time, Throughout the approach, the difference between heading and bearing are negligible. Beginning in the initiation phase, the heading angle begins to change prior to change in the flight path. This suggests that the bat is using yaw rotation to reorient into the turn during the initiation phase of the U-turn. This closely mirrors observations seen by Iriate-Diaz and Swartz where turn initiation was mediated by yaw rotation . The devThe bat sustains a roll angle of approximately 20–25 degrees throughout the approach phase of the flight. This rapidly increases beginning at cycle 3 during the initiation phase of the U-turn to a final maximum of nearly 40 degrees. The peak roll angle is observed during end of the initiation phase and remains elevated throughout the apex before decreasing during egress. The increase in roll angle from 20 to 40 degrees closely corresponds to the point at which the bearing angle begins to change rapidly during cycle 4. Taking the heading, bearing, and roll angle together, we can conclude that the bat begins yaw rotation early in the U-turn which persists throughout the entire U-turn, while in contrast the change in bearing is related somewhat to the yaw but more significantly to the increase in roll angle.The elevation angle describes the upward inclination angle of the bat’s body while the climb angle describes the inclination of the velocity vector. Prior studies have indicated that the elevation angle is persistently higher than the climb angle during all modes of flight . That iExamination of the bat’s body and velocity orientation angles suggests that rolling is responsible for a large portion of the bearing angle change during the U-turn. In order to further investigate this phenomenon, The vertical force, although defined relative to the ground vertical axis, shows a similar trend to the body frame lift force. That is, when the bat begins to climb in the approach phase the vertical force is maximum. As the rate of height gain decreases throughout the initiation and apex phases, the vertical force decreases. As the bat egresses the U-turn, it arrests its rate of descent by slightly beginning to increase the vertical force to a magnitude which supports its weight. This serves to arrest its descent towards a more gradual downward trajectory preventing a precipitous loss of altitude. The tangential force remains negative over the first four cycles corresponding to the observed deceleration. This is critical to maneuvering a tight turn since it decreases the required centripetal force to achieve a given radius of curvature. For a bat of a given mass to achieve a turn of a particular radius of curvature, the radial force requirement increases with the square of the tangential velocity. That is, to achieve a turn with a radius of 6 cm, a bat flying at 1 m/s would need to achieve 4 times the radial force compared to a 0.5 m/s tangential flight velocity. For the present flight, the negative tangential force causing deceleration is minimum during the initiation phase of the U-turn, specifically during the third wingbeat cycle.The radial force causes a centripetal acceleration of the bat causing a change in trajectory of the flight. This centripetal acceleration directly causes the change in bearing angle shown in The radial force as shown in Explanation of the moments is best conducted by observing general trends in the plots. This is because there are a few factors which contribute to the challenge of interpreting rotational moments in a very specific time-dependent manner. First, as the wings flap the location of the center of mass shifts thus the moments shown are only an estimate of the precise rotational moment. Second, the rotational moments are derived only from the aerodynamic forces. In addition, inertial moments may also contribute to reorienting the bat’s body. Thus, the aerodynamic moments are not guaranteed to explain 100% of the body rotation. However, despite these caveats, the trends in the aerodynamic moments are largely consistent with the observed changes in angular orientation. Additionally, comparing the aerodynamic moments and the angular acceleration can provide insight as to the relative contribution of aerodynamic mediated rotation versus inertia mediated rotation.Negative yaw moment (right yaw) is observed during the downstroke of cycles 2–4 during the period of the turn when yaw angular velocity is increasing. Subsequently, during the later portion of the apex and moving into the egress, the rate of yaw rotation decreases and correspondingly the yaw moment becomes positive. This trend in the yaw moment corresponds to the trend observed in the angular acceleration. In addition, both yaw moment and yaw acceleration vary substantially between the upstoke and downstroke; during the downstroke, yaw moment and acceleration is directed into the turn while counter rotation is observed during the upstrokes. During the initiation, the magnitude of the right yaw during the downstroke is greater than the left yaw during the upstroke resulting in a net right rotation. The yaw rotational acceleration is slowed during the apex and egress of the U-turn. It is important to recognize that the yaw moment and angular acceleration describe the rate of change of the angular velocity—thus despite the rate of yaw rotation decreasing during the apex and egress, the yaw angular velocity maintains a right rotation through the duration of the flight. That is, the rate of right yaw rotation slows during the later portion of the maneuver but right rotation persists throughout the maneuver.Both the roll and yaw moments are highly variable between the upstroke and downstroke. Generally, for a right turn, right roll and right yaw are maximum during each downstroke and reverse during each upstroke. This provides two available mechanisms for increasing net moment across a complete wingbeat cycle. Either the downstroke moment may be elevated or the reverse moment during the upstroke may be mitigated. Thus despite the majority of the right roll and right yaw moment generation during the downstroke, modulation of the moment during the upstroke will contribute to the net moment experienced over the course of a full wingbeat cycle. An additional consideration is that roll rotation may be mediated by inertial effects. Roll moment is positive during downstrokes 1 and 2, indicating right roll; however, throughout the initiation phase (cycles 3–4), the aerodynamic roll moment does not appear to fully explain the roll angular acceleration shown in xb-force will cause yaw moments while asymmetry in the zb-force will cause roll moments.In order to examine the source and nature of the aerodynamic moments at various points in the wingbeat cycle, the aerodynamic force in the body frame is broken up by the region of the wing on which it acts and is shown in The thrust on the outer left wing relative to the inner left wing is elevated throughout the downstrokes of the initiation phase of the turn. In general, thrust generated by the outer wing will have a disproportionally larger contribution to aerodynamic moment relative to the inner wing since the moment arm is longer. The wingspan of around 50 cm is substantially longer than other dimensions of the bat such as the mean wing chord or the body length, so small asymmetries on the outer wing can have a large rotational effect. This appears to contribute to the yaw moment generated throughout the approach and initiation phase of the turn.Fz,b between the right and left wings is marginal throughout the flight; however, the specific location on the wing at which the force acts will change the length of the moment arm. During downstrokes 2–3, the lift generated on the right outer wing is depressed causing a net right roll moment corresponding to the increase in bank angle which occurs throughout the initiation phase of the turn.Lift force is overwhelming generated during the downstroke of each cycle. This aligns with the observation that right roll moment is generated almost exclusively during the downstrokes. Asymmetry in In order to investigate the power requirement of a tight U-turn maneuver, total power expenditure was calculated over the entire flight. Total power  is the sTotal power is elevated throughout the approach (cycles 1–2) corresponding with the time at which the bat is initiating its climb. This agrees with prior data which indicated that vertical height gain is a power intensive mode of flight. Total power expenditure remains elevated throughout the maneuver when compared to the cost of straight flight. At the apex of the U-turn, the cycle mean power expenditure of 0.49 W is about 1.44 times higher than what has been previously calculated for the same bat in straight flight (cycle mean of 0.34 W) as shown in Analysis of the wing kinematics in conjunction with aerodynamic parameters during each of the four phases of the flight provides several insights into the mechanisms the bat is using to execute a U-turn maneuver. As the bat climbs and decelerates during the initiation of the turn, the wingbeat frequency decreases and the flap amplitude increases. The right wing on the inside of the turn exhibits a greater flap amplitude compared to the left wing, and extends across the body toward the center axis of the body during the end of the downstroke and beginning of the upstroke. This phenomenon can be clearly seen in the wingtip locus visualization and manifests as a very high positive stroke plane deviation angle in the right wing during the initiation and apex of the U-turn. Lateral movement of the right wing causes an inertial effect causing counter rotation of the body to conserve angular moment. However, the presence of aerodynamic yaw moment suggests that the yaw rotation is not simply an inertia rotation but a combined aerodynamic and inertial mechanism.The bat generates steady modest yaw rotation throughout the approach and initiation of the U-turn during both the upstroke and downstroke to reorient the body. Throughout the initiation phase the bank angle nearly doubles from 20 to 40 degrees causing a large lateral force. This causes the bearing angle to change rapidly throughout the fourth and fifth cycles eventually catching up to the more gradually changing yaw angle in the sixth cycle. In addition to the high roll angle, the slower flight velocity allows the lateral force to more quickly turn the bat since the required centripetal force is lowered.From this analysis, we can make several high level observations about the U-turn flight. The bat’s ability to rapidly yaw appears to be limited to a degree so the yaw rotation began about one to two cycles before the rapid bearing angle change and was stretched out over many wingbeat cycles. During the apex of the turn, the bat combined a high roll angle with a low flight velocity magnitude to very rapidly redirect its bearing direction and negotiate a low radius of curvature flight trajectory. Right roll moments and right yaw moments were primarily generated during the down stroke phase of the wingbeat cycle. The general trends in aerodynamic moment and angular acceleration of the body were correlated, but they did not precisely match on an instantaneous basis suggesting a shared contribution of inertial and aerodynamic mediated rotation mechanisms.In the future, further investigation of maneuvers executed by different bat species at different flight velocities and turning radii will allow a more generalized understanding of how bats turn. We believe this study highlights the importance of simultaneous kinematic and aerodynamic analysis in order to understanding the turning mechanisms being employed. A general model of how various different bat flight maneuvers are executed would be a valuable tool for both understanding bat biomechanics and enabling novel design of bat-mimetic micro air vehicles.S1 AnimationAnimation of the U-turn maneuver using results from the numerical aerodynamic simulation. Isosurfaces of coherent vorticity are shown along with contours of pressure coefficient differential on the wing surface (pressure below the wing minus pressure above the wing).(MP4)Click here for additional data file.S1 Video framesA time series of video frames of the bat executing the u-turn maneuver are provided. The video was recorded at 120 frames per second, so the time separating each subsequent frame is 8.33 ms.(RAR)Click here for additional data file.S2 Video framesA time series of video frames of the bat from a second camera perspective complementing (RAR)Click here for additional data file. 4 Aug 2020PONE-D-20-20383Analysis of a 180-degree U-turn maneuver executed by a Hipposiderid batPLOS ONEDear Dr. Windes,Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.Please submit your revised manuscript by Sep 18 2020 11:59PM. 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Thank you for including your ethics statement:  "Ethical bat housing and handling guidelines specified by Virginia Tech’s Institutional Animal Care and Use Committee (IACUC protocol number 15-067) were followed throughout the study".   Please amend your current ethics statement to confirm that your named ethics committee specifically approved this study.http://journals.plos.org/plosone/s/submission-guidelines#loc-animal-research  For additional information about PLOS ONE submissions requirements for ethics oversight of animal work, please refer to Once you have amended this/these statement(s) in the Methods section of the manuscript, please add the same text to the “Ethics Statement” field of the submission form (via “Edit Submission”).5. We note you have included a table to which you do not refer in the text of your manuscript. Please ensure that you refer to Table 2 in your text; if accepted, production will need this reference to link the reader to the Table.[Note: HTML markup is below. Please do not edit.]Reviewers' comments:Reviewer's Responses to QuestionsComments to the Author1. Is the manuscript technically sound, and do the data support the conclusions?The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes**********2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes**********3. Have the authors made all data underlying the findings in their manuscript fully available?PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.The Reviewer #1: Yes**********4. Is the manuscript presented in an intelligible fashion and written in standard English?PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.Reviewer #1: Yes**********5. Review Comments to the AuthorPlease use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. Reviewer #1: The authors used 3D optical motion capture and aerodynamic simulations to investigate a U-turn maneuver executed by a great roundleaf bat.Over the course of the entire flight, the bat first begins to gradually turn and climb, then executes a tight U-turn, and lastly descends while exiting the turn. This sequence was categorized into four phases. Analysis of the wing kinematics in conjunction with aerodynamic parameters during each of the four phases of the flight provides several insights into the mechanisms the bat is using to execute a U-turn maneuver.The topic is important and within the scope of PLOS ONE. The manuscript is well written.I would like to recommend it for publication. However, I think the following suggestion would be helpful to improve the quality of the manuscript.1. The authors pointed that "certain unsteady mechanisms such as enhanced lift by the leading edge vortex (LEV) have been shown to be nearly ubiquitous in flapping flight, while other mechanisms such as clap and fling are only observed in certain insects operating at smaller length scales" on page 9. I think it is better to also point that bats can dynamically changing wingspan to enhance lift , 20150821,2015; Physics of Fluids, 26(6), 061903, 2014; Physics of Fluids, 27(6), 061901, 2015)2. The authors use 44 cells per wing chord length in the simulations. The required number of cells in numerical simulations depends strongly on the Reynolds number of the flows. What is the typical Reynolds number in the simulations?3. What is the initial flow condition for the simulations?4. I suggest the authors to provide the details of the definition of force coefficients in Figure 7.**********what does this mean?). If published, this will include your full peer review and any attached files.6. PLOS authors have the option to publish the peer review history of their article  digital diagnostic tool,  11 Oct 20201. The authors pointed that "certain unsteady mechanisms such as enhanced lift by the leading edge vortex (LEV) have been shown to be nearly ubiquitous in flapping flight, while other mechanisms such as clap and fling are only observed in certain insects operating at smaller length scales" on page 9. I think it is better to also point that bats can dynamically changing wingspan to enhance lift , 20150821,2015; Physics of Fluids, 26(6), 061903, 2014; Physics of Fluids, 27(6), 061901, 2015)Author Reply: We have added the reference per the suggestion.2. The authors use 44 cells per wing chord length in the simulations. The required number of cells in numerical simulations depends strongly on the Reynolds number of the flows. What is the typical Reynolds number in the simulations?Author Reply: The Reynolds number varies with flight velocity (as the bat is slowing down during the u-turn), but ranges from 4,000 to 10,000. We have mentioned this in the text.3. What is the initial flow condition for the simulations?Author Reply: The initial flow condition is zero absolute velocity (since the bat is flying in stagnant air in the flight tunnel), and we allow several time steps for the flow to develop. Since the reference frame is moving, the velocity field was initialized at the reference frame velocity. We have mentioned this in the text.4. I suggest the authors to provide the details of the definition of force coefficients in Figure 7.Author Reply: We have added this definition.AttachmentAuthor_response.pdfSubmitted filename: Click here for additional data file. 13 Oct 2020PONE-D-20-20383R1Analysis of a 180-degree U-turn maneuver executed by a Hipposiderid batPLOS ONEDear Dr. Windes,Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.Please submit your revised manuscript by Nov 27 2020 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at Please include the following items when submitting your revised manuscript:A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocolsIf applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: We look forward to receiving your revised manuscript.Kind regards,Fang-Bao TianAcademic EditorPLOS ONEAdditional Editor Comments (if provided):Thank you for revising your work. I have checked it, and would like to request a minor revision regarding the definitions of Reynolds number and lift coefficient. In 3.3, the lift coefficient is defined by using "the mean flight velocity". I think this reference velocity can be used in the definition of Reynolds number. By the way, it is better to use "lift coefficient" instead of "force coefficient" in 3.3.[Note: HTML markup is below. Please do not edit.]https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool,  15 Oct 2020please see the file author response2.docxAttachmentauthor_response2.docxSubmitted filename: Click here for additional data file. 16 Oct 2020Analysis of a 180-degree U-turn maneuver executed by a Hipposiderid batPONE-D-20-20383R2Dear Dr. Tafti,We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at onepress@plos.org.If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact Kind regards,Fang-Bao TianAcademic EditorPLOS ONEAdditional Editor Comments :Reviewers' comments: 23 Oct 2020PONE-D-20-20383R2 Analysis of a 180-degree U-turn maneuver executed by a Hipposiderid bat Dear Dr. Tafti:I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. onepress@plos.org.If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact plosone@plos.org. If we can help with anything else, please email us at Thank you for submitting your work to PLOS ONE and supporting open access. 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All samples were produced by room temperature pressing–free sintering method. All of the fillers were blended with PTFE by intensive dry mechanical stirring; the efficiency of the blending was analysed by Energy-dispersive X-ray spectroscopy (EDS) method. Compared to neat PTFE, graphene in 4/8/16 wt % improved the thermal conductivity by ~29%/~84%/~157%, respectively. All fillers increased the storage, shear and tensile modulus and decreased the ductility. PTFE with 4 wt % Al2O3 content reached the lowest wear rate; the reduction was more than two orders of magnitude compared to the neat PTFE.In this research work, unfilled and mono-filled polytetrafluoroethylene (PTFE) materials were developed and characterised by physical, thermal, viscoelastic, mechanical, and wear analysis. The applied fillers were graphene, alumina (Al Nanoparticle filled thermoplastics are widely investigated materials due to their beneficial features. These nanoparticles can enhance the mechanical, thermal properties and flame retardancy of the thermoplastics and they can achieve a significant improvement of wear resistance as well ,2,3,4,5.2O3) nanofillers can improve the wear resistance of PTFE by 2 to 3 orders of magnitude [It is well known in the literature that graphene and alumina (OH)16·4(H2O), MG70) are also potential filler candidates in thermoplastic matrices. They have a high number of functional groups, which can be promising to increase the wear-resistance of thermoplastics as they can initiate a higher number of complex formation due to their extra functional groups [Boehmite alumina (AlO(OH), BA80) and hydrotalcite . The applied graphene was xGnP® Graphene Nanoplatelets Grade M from XG Sciences . The average particle size was ~25 µm. The applied 1015WW alpha alumina (Al2O3) with 99.5% purity was produced by Nanostructured & Amorphous Materials Inc. . The average nanoparticle size was between 27 and 43 nm. The applied boehmite alumina (AlO(OH)) was Disperal® 80 (BA80) from Sasol  with 35 µm average particle size and 80 nm average crystallite size. Al2O3 content of BA80 was 80%. Pural® MG70 hydrotalcite (MG70) from Sasol  has a double-layered metal hydroxide structure including magnesium and aluminium hydroxides . It had ~45 µm average particle size.The used polytetrafluoroethylene (PTFE) powder was 3MThe composition of the produced PTFE-based materials can be seen in Disc-shaped samples were pressed with 10/120 mm diameter and 4 mm thickness. Specimens with 10 mm diameter were used for compressive tests, and all other specimens were cut out or milled from the samples with 120 mm diameter. The results of repeatability tests are introduced with the mean and standard deviation values related to ±1σ.−1 in wavenumbers.Raman spectrometry was carried out with a Horiba Jobin Yvon Labram 300 spectrometer  equipped with charge-coupled device (CCD) detector and 532 nm Nd-YAG LASER. The grating was 1800 grooves/mm. The investigated spectrum range was between 1789 and 346 cmEnergy-dispersive X-ray spectroscopy (EDS) investigations were carried out with a JEOL JSM 6380LA device  with 15 kV accelerating voltage, 10 sweep counts and 0.1 msec dwell time. The sufficient electron conductivity of the samples was provided by sputtering of the surface with gold (Au) in a JEOL FC-1200 device. Micrographs were taken in high vacuum mode.The density of the sintered samples was estimated by immersion method (ISO 1183-1:2012). The mass of the samples was measured first in air, and afterwards in ethanol. The mean and standard deviation values were calculated from at least five measurements.The thermal conductivity of the unfilled/filled PTFE was measured by a thermal conductivity measurement device, developed at the Department of Polymer Engineering of BME  ,18. The Dynamic mechanical analysis (DMA) was carried out with a TA Instruments DMA Q800 device  in multi-frequency-strain mode. Three-point bending configuration was applied, the distance between the supports was 20 mm. The applied temperature range was between −120 and 330 °C with 3 °C/min heating rate and 1 Hz frequency. The isothermal dwelling time at −120 °C was 5 min. The applied oscillation strain was 0.05% with 6 N static force.Hardness measurements were carried out with a Zwick H04.3150.000 digital hardness tester  in Shore-D measurement range.The compressive properties of the filled/unfilled PTFE samples were measured by a Zwick Z020 universal tester  equipped with a 20 kN load cell. The tested cylindrical samples had 10 mm diameter and 10 mm height. The crosshead speed during the test was 2 mm/min.The shear tests were carried out with the use of Iosipescu shear test method set up. All tests were run according to ASTM D 5379-05 standard. The strain measurement was performed with a Digital Image Correlation (DIC) measurement system (Mercury Monet with 5 MP camera). The shear properties of the polymer samples were measured by a Zwick Z020 universal tester equipped with a 20 kN load cell. The crosshead speed during the test was 2 mm/min. With this test method, the shear properties of materials can be determined by the use of V-notched beams (4 mm notch depth on each side). The samples had 80 mm length, 20 mm width and 4 mm thickness.The tensile properties of the filled/unfilled PTFE samples were measured by a Zwick Z250 universal tester equipped with a 20 kN load cell (EN ISO 527-2). The crosshead speed was 10 mm/min until 0.5% strain and 100 mm/min after 0.5% strain. The dumbbell-shaped sample size was 80 mm total length, 60 mm neck length, 5 mm neck width, and 4 mm thickness.Related to the hardness, compressive, shear and tensile tests, the mean and standard deviation values were calculated from at least five measurements.3/Nm), 3), The tribological characterisation was performed with a Wazau TRM 1000 tribometer from Dr.-Ing. Georg Wazau Mess- und Prüfsysteme GmbH, Germany. The applied configuration was pin-on-disc with excentrically rotating cylindrical polymer pin and stationary steel disc counterface. The counterface material was 42CrMo4. All disc counterfaces were surface finished by turning to nominal Ra 0.3 µm average surface roughness in a spiral pattern. The investigated polymer pin samples had a diameter of 8 mm with 5 mm thickness (length), while the counterfaces had a diameter of 50 mm. The wear track centreline on the steel discs was at 30 mm diameter. The applied sliding speed was 61 rpm , while the applied normal force was 151 N (corresponding to 3 MPa contact pressure). The total sliding distance per test was set at 1000 m. The mean and standard deviation values were calculated from at least 5 measurements. The specific wear rate of polymer samples was calculated after wear testing by using Equation (1):2O3-4, PTFE/BA80-4 and PTFE/MG70-4 samples were analysed by Raman spectroscopy or EDS. The samples were fractured after being cooled down in liquid nitrogen (−196 °C).The freeze-fractured (cryo-fractured) surfaces of PTFE/graphene-4, PTFE/AlThe Raman spectra of PTFE/graphene-4 can be seen in −1, which comes from the graphene content of the area. These spectra indicate that there was no significant graphene migration or diffusion from the core to the edge (pressed surface of the sample) neither at the room temperature pressing nor at sintering temperature.The graphene dispersion was checked in eight locations at different depths from the pressed surface b. In all2O3-filler in PTFE/Al2O3-4 was analysed by EDS mapping at four different locations as a function of depth from the pressed surface. 2O3-powder also can be seen. The size of these finer filler particles was below 1 µm. The significant aluminium peak  was also shown by the EDS spectrum  as a function of temperature can be seen in 2O3, BA80 and MG70 improved the storage modulus at 20 °C by ~138%, ~33%, ~54%, and ~67%, respectively  respectively. PTFE/MG70-1 and PTFE/MG70-4 samples had the same values as the reference unfilled PTFE.The hardness values of the sintered materials can be seen in 2O3-1 and PTFE/Al2O3-4 samples did not reach significantly higher compressive stress compared to neat PTFE, while their compressive modulus increased remarkably. MG70 filler decreased both the compressive stress and modulus. Graphene with low filler content  did not change the compressive properties remarkably, while BA80 in 1 and 4 wt % increased the compressive modulus significantly compared to neat PTFE. In higher filler content, BA80 is observed as a superior additive compared to graphene filler. Samples with 8 and 16 wt % BA80 reached the same level of compressive modulus as neat PTFE, while the application of graphene in higher percentages decreased both compressive stress and compressive modulus significantly. This is attributed to the low density of graphene, which resulted in a high volume fraction of graphene in the developed PTFE/Graphene-8 and PTFE/Graphene-16 samples. PTFE/Al2O3-1, PTFE/BA80-4 and PTFE/Al2O3-4 samples reached the highest improvement in compressive modulus which was ~34.2%, 33.1% and 32.6% higher compared to neat PTFE, respectively.The compressive properties of the sintered samples are introduced in As it is introduced in The shear properties of the unfilled and filled PTFE samples are introduced in The tensile properties of the unfilled and filled PTFE samples are introduced in −4 (mm3/Nm) wear rate. The lowest wear rate was reached with PTFE/Al2O3-4 polymer samples with a value of 2.91 × 10−6 (mm3/Nm), which is more than two orders of magnitude improvement compared to the reference neat PTFE. It is in agreement with the results of Krick et al. who also reached two to three orders of magnitude enhancement in wear resistance with the use of 5 wt % alumina in PTFE matrix [2O3-1 had ~82% reduction in wear rate compared to unfilled PTFE. Graphene in 4/8/16 wt % filler content also significantly decreased the wear; the reduction was around one to two orders of magnitude with a value of 4.72 × 10−5, 3.17 × 10−5 and 8.51 × 10−6 (mm3/Nm), respectively. Kandanur et al. also registered a tendency with increasing wear resistance as the graphene filler content increased [2O3 fillers are in agreement with the literature [The calculated specific wear rates of the tested unfilled/filled PTFE samples are presented in ncreased . The weaterature .2O3-4 material had the lowest wear rate, with a low shear modulus and high compressive modulus compared to the other PTFE-based materials. In contrast with this, PTFE/graphene–16 had the second lowest wear rate, but it has the highest shear modulus and the lowest compressive modulus. The low wear rate of PTFE/Al2O3-4 material can neither come from its thermal conductivity, hardness or tensile modulus, as these properties only slightly changed compared to neat PTFE. It means that focusing on the wear rate, the dominating factor can only be the type of the applied fillers  and in this way the transfer layer formation. The applied filler and, consequently, the transfer layer formation can have a dominating (primary) role in the wear mechanism of the investigated materials.The wear rate as a function of the shear and compressive modulus is depicted in It is also important to mention that the higher tensile/shear modulus and thermal conductivity can also affect the wear resistance of the materials. E.g., the higher thermal conductivity can be beneficial in wear process as more frictional heat can be removed from the contact surface. As a result, the surface temperature of the polymer is decreasing, which results in a smaller reduction in the mechanical properties of the polymer. Focusing on graphene filler, it can be seen that the wear rate was decreased as the filler content increased, and simultaneously the tensile/shear modulus and thermal conductivity were increased as the filler content increased. In opposition to this, in the case of BA80 filler, the wear rate was not remarkably influenced by the increased filler content and accompanying increased shear and tensile modulus. As a conclusion, it can be stated that the shear/tensile properties and thermal conductivity have only a secondary role in the wear mechanism of the investigated materials.In this research, the physical, thermal, viscoelastic, mechanical, and wear analysis of neat PTFE and graphene, alumina, boehmite alumina, and hydrotalcite-filled PTFE were introduced.The applied blending method was an intensive dry mechanical stirring, which is suitable to make homogeneous blends. The homogeneity of the powder blends was investigated by EDS/Raman spectrometry.Graphene filler due to its excellent thermal properties remarkably increased the thermal conductivity of PTFE-based samples. Compared to neat PTFE, graphene in 4/8/16 wt % improved the thermal conductivity with ~29%/~84%/~157%, respectively.Compared to neat PTFE, the shear and tensile modulus of the developed mono-filled samples were increased together with the increase of the filler content. It is in line with the changes in storage modulus measured by DMA tests. All the applied fillers increased the storage modulus of PTFE. In agreement with the changes observed for the shear, tensile and storage modulus, the elongation at yield strength and the measured elongation during shear tests were significantly reduced with decreasing filler content. This reduced ductility, and the increase of the modulus values can be explained based on the restricted molecular chain motion caused by the applied fillers.Focusing on the compressive properties, with higher filler content (8 and 16 wt %), boehmite alumina is observed as a superior additive compared to graphene filler. Graphene significantly decreased the compressive stress and modulus compared to neat PTFE. Samples with lower alumina or boehmite content remarkably increased the compressive modulus.As the peak temperature of β-transition of PTFE is close to room temperature (19–20 °C), compressive tests at 50 °C were carried out as a confirmation of the measurements run at room temperature. The tendencies of the registered compressive stress and modulus values between room temperature (23 °C) and 50 °C are close to each other. It means that at the temperature range of the β-transition of PTFE, the ratio of the mechanical performance of the measured specimens does not change remarkably. It is in agreement with the measured storage modulus of the samples.2O3-4 polymer samples had the lowest wear rate, reaching more than two orders of magnitude improvement compared to the neat PTFE. This ultra-low wear rate is not induced by the modified thermal conductivity, hardness or compressive/shear/tensile modulus as these values only slightly changed compared to the neat PTFE. It is supposed that this improvement comes from the modified transfer layer formation.PTFE/AlThe type of filler has a dominating (primary) role in wear mechanism. The increased shear/tensile properties and thermal conductivity have a lower influence on the wear mechanism (secondary role) in case of the investigated PTFE-based materials.The developed alumina and graphene-filled PTFE materials can be used in a wide field of tribological applications, e.g., as sliding bearings or seals. Focusing on the wear results, the suggested compositions are 4 wt % alumina or 4–16 wt % graphene, as these materials reached more than one order of magnitude enhancement in wear resistance.


Annealing in an ultra-high vacuum at ca. 773 K allows for the removal of impurities formed on the surface of films during the synthesis and transfer procedure and changes the chemical state of nitrogen in nitrogen-doped graphene. Core level XPS spectra detect a low n-type doping of graphene film when nitrogen or phosphorous atoms are incorporated in the lattice. The electrical sheet resistance increases in the order: graphene < P-graphene < N-graphene. This tendency is related to the density of defects evaluated from the ratio of intensities of Raman peaks, valence band XPS and NEXAFS spectroscopy data. Heteroatom doping is a widely used method for the modification of the electronic and chemical properties of graphene. A low-pressure chemical vapor deposition technique (CVD) is used here to grow pure, nitrogen-doped and phosphorous-doped few-layer graphene films from methane, acetonitrile and methane-phosphine mixture, respectively. The electronic structure of the films transferred onto SiO Planar graphene sheets possessing a good electrical conductivity and mechanical strength as well as transparency and flexibility are very attractive for advanced electronics and energy applications ,2. The cThe use in the CVD process of molecules containing non-carbon atoms is a practical way to initiate the heteroatom doping of graphene ,11. The n-doping of graphene [p-type graphene doping with the insertion of pyridinic N and no electron/hole doping by pyrrolic N [n-type doping of graphene with substitutional phosphorus [Direct substitution of carbon by nitrogen results in the graphene . This fographene . At low graphene ,22. The rrolic N . Surprisrrolic N ,25,26. Prrolic N . The stuosphorus ,28,29.4/H2 at 1323 K (pure graphene), CH3CN/H2 at 1123 K (N-graphene) and CH4/PH3/H2 at 1173 K (P-graphene). The films transferred onto the SiO2/Si substrates were studied by Raman, X-ray photoelectron spectroscopy (XPS), near-edge absorption fine structure (NEXAFS) spectroscopy and electrical conductivity measurements. We showed that an annealing of the films in a vacuum is a necessary step to remove the surface contaminations and it modifies the electronic state of the constituting elements. The changes in the sheet resistance were related with the alternations observed experimentally in the valence and conduction bands of pure graphene film upon the insertion of nitrogen and phosphorus.In current work, we report the synthesis of few-layer graphene films on copper substrates using low pressures of a gaseous mixture of CH−1 and then naturally to ca. 423 K. Then, the reactor was evacuated, filled with a carbon-containing gas and hydrogen to pressure values of 400 Pa and 2000 Pa, respectively, and heated to a required temperature. The synthesis was conducted for 0.3 h, and after that the oven was moved away from the foil and the reactor was cooled down at a rate of ca. 2 grad min−1. Pure graphene was synthesized from methane at 1323 K. 40 Pa of phosphine was added to methane for the growth of P-graphene at 1123 K, and N-graphene was produced from acetonitrile at 1173 K [Graphene films were grown on electrolytic 35 µm thick copper foils  using the low-pressure variant of the CVD method. Details of the pretreatment of copper foil and the design of tubular CVD reactor equipped with a moveable oven can be found in . One squt 1173 K . The copper foil was etched in an aqueous solution of iron (III) chloride (30 wt.%) for 2 h. Cooper-free graphene film was washed twice in diluted HCl (10 wt.%) and then in deionized water to neutral pH. The floating graphene was caught by a silicon substrate with a 300-nm surface oxide layer. The sample was dried in laboratory conditions. 2/Si were taken using a BX 51TRF  optical microscope and S-3400N  scanning electron microscope (SEM). Raman spectra were recorded using an excitation from an Ar+ laser at 514 nm on a LabRAM HR Evolution  spectrometer. Electrical characterization of the films was carried out on a four-point probe station MPS150-C1A  by Van der Pauw method under ambient conditions. Electrodes were deposited by silver conductive paint on each corner of graphene film, with a size of ca. 5 × 5 mm2.The images of the films on SiO−9 mbar. An excitation photon energy was 830 eV for XPS overall spectra and C 1s spectra, 830 and 500 eV for N 1s spectra, and 200 eV for P 2p spectra. The spectra were fitted using a Gaussian/Lorentzian function, except of the sp2-component in C 1s spectra, where a Doniach–Sunjic high-energy tail was added to that function. Valence-band XPS spectra were measured at 100 eV. Energies of XPS spectral lines were calibrated to the Au 4f7/2 component position with an accuracy of ca. 0.05 eV. The XPS and NEXAFS experiments were carried out using monochromatized synchrotron radiation from the Russian–German beamline (RGBL) at the Berliner Elektronenspeicherring für Synchrotronstrahlung . The angle between the incident radiation and the graphene surface was 55°. NEXAFS spectra near the C K-edge were acquired in the total electron yield (TEY) mode. The base pressure in the measurement chamber was better than 102/Si substrate is visible, owing to the absorption of ca. 2.3% of white light [The graphene monolayer located on a SiOte light . Figure 4 on copper substrate within the density functional theory (DFT) showed that these processes rarely occur below 1073 K [It has been shown previously that the determining step for the formation of continuous graphene film is the attachment of carbon species to the graphene edges . The prow 1073 K . For thew 1073 K . CompareD/IG) is often used for the estimation of the density of the defects. Topological defects, edge states and stacking faults of the layers are most likely responsible for the D peak activation in pure graphene film. The intravalley phonon scattering at defects produces the D’ peak [Raman spectroscopy is an indispensable method for the structural characterization of graphitic materials . Raman s D’ peak . Peaks 2−1 at the used wavelength) and this corresponds to low electron-doping [−1 for the N-graphene could be due to hole-doping. Moreover, it was shown that the G and 2D peaks shift to the same side for hole-doping [2D/G) is a parameter dependent on doping density [2D/IG value may be less than unity when the concentration of nitrogen in graphene monolayer is ~0.25–0.35% [Phonon scattering is dependent on electrons and any variation of electronic structure modifies the Raman peaks . An upshn-doping . The upse-doping  and such density . This ra25–0.35% . Since R2D/IG value from Raman scattering cannot be used to determine the thickness of heteroatom-doped graphene. The number of layers in graphene films was evaluated from overall XPS spectra after annealing the samples in the spectrometer chamber at 773 K for 1 h. The spectra exhibited a dominant C 1s line and the core lines of oxygen and silicon from the oxidized silicon surface a. The hi2/Si substrates before annealing in a vacuum. In addition to an intense component corresponding to sp2-hybridized carbon areas, the spectra have a set of components at higher binding energies. The component at ca. 284.9 eV in the spectrum of pure graphene film is attributed to disordered carbon, which is intermediate between sp2 and sp3 states [2/Si and/or contact with laboratory air. 3 states . These c3 states , C-H bon3 states . The hig2 C=N and sp3 C–N bonds are around 285.8 and 287.1 eV, respectively [2 component in the spectrum of N-graphene. The shift of the C 1s core line is attributed to p- or n-type doping when the binding energy decreases or increases, respectively. However, the contact of carbon atoms with highly electronegative oxygen can be another factor causing a positive charging of the graphene network. The same shift of the sp2 and disordered components observed in the spectrum of N-graphene, relative to the positions of corresponding components for pure graphene, may be due to the influence of oxygen. The disordered carbon component is upshifted by ca. 0.4 eV in the spectrum of P-graphene and ca. 0.7 eV in the spectrum of N-graphene b. The boectively . These v2 components  in the graphene lattice. These variable parameters are listed in graphene . It has graphene . Our rescted C–H b and N–Hcted C–H a. Annealenomenon . Compared to homogeneous graphene film, the P-graphene and N-graphene films have shown a domain structure a,b. The D/IG value for N-graphene compared to P-graphene , which require different energies for the activation and attachment to the edges of a growing domain. As the result, the edges of the adjacent domains may connect tightly or weakly, forming a compact or sparse boundary. The measurements of the electrical properties of the films detected a larger sheet resistance of graphene films with heteroatoms . The n-tgraphene . Thus, wgraphene a. Therefn-type doping of graphene. Pyridinic N induces p-doping, while in the hydrogenated form it can behave as an n-type dopant [n-doping of graphene [The insertion of nitrogen and phosphorous in graphene can be achieved during the synthesis or post-synthesis treatment. Chemical forms of the embedded heteroatoms and electronic structure of the obtained material depend on the synthesis method, as well as the used parameters. In the post-synthesis treatment, the nature of the initial graphene material is also important. Particularly, the treatment of few-layer graphene may introduce heteroatoms only in the surface layers. The synthesis, characterization and properties of heteroatom-doped graphene nanomaterials are described in the recent reviews ,11,12,70e dopant . The effgraphene . Our exp2/Si substrates to study the structure by Raman spectroscopy, the electronic state by XPS and NEXAFS spectroscopy, and the electrical properties in the air at room temperature. Raman scattering revealed an increase of disorder in the graphene films with heteroatoms. The largest ratio of ID/IG and the smallest ratio I2D/IG were observed in the N-graphene spectrum. An upshift of the Raman peaks in this spectrum was related to the strong distortion of carbon bonds with the incorporation of nitrogen atoms and especially of pyrrolic N. The N 1s spectrum showed the predominance of this form in raw N-graphene. Annealing of the graphene samples in an ultra-high vacuum at 773 K for 1 h substantially reduced the amount of oxygen groups, developed during the wet transfer procedure and storage of samples in air environment, and defects in the graphene lattice. A comparison of the C 1s spectra of the annealed samples observed an upshift of the peaks for N-graphene and even more for P-graphene. This shift can be attributed to n-type doping of the graphene samples and might explain the increase of the sheet resistance, as related to pure, p-doped graphene. However, the change in the sheet resistance does not correlate with the doping level, estimated from the XPS data. Based on this fact, we concluded that scattering centers, created by heteroatoms and boundaries of domains, contribute to the sheet resistance. The poor connection of boundaries in N-graphene could be a reason of its lowest conductivity. NEXAFS and XPS spectra of this film detected many localized states around the Fermi level, which most likely correspond to the edges of domains and vacancies. These states can serve as adsorption sites in the sensors and scatters of phonons in devices where the control of thermal conductivity is important.We have compared three graphene films, synthesized by low-pressure CVD method on copper foils, pretreated in the same way. Methane and acetonitrile provided the necessary species for the growth of graphene and N-graphene, respectively, and P-graphene was produced using a mixture of methane and phosphine, taken in the ratio 10:1. The synthesis temperature was 1323 K for pure graphene, 1123 K for P-graphene and 1173 K for N-graphene. The lowering of the temperature and its addition to the reaction mixture heteroatoms resulted in the formation of different size domains in P-graphene and N-graphene. The films were successfully transferred to SiO


The harvester can work under the multiple channel mode, harvesting energy simultaneously from different flows of wireless energy in the air. This research will open a new avenue for wireless harvesting by using the ultrafast process of quantum tunneling and unique physical properties of graphene.Recharging the batteries by wireless energy facilitates the long-term running of the batteries, which will save numerous works of battery maintenance and replacement. Thus, harvesting energy form radio frequency (RF) waves has become the most promising solution for providing the micropower needed for wireless sensor applications, especially in a widely distributed 4G/5G wireless network. However, the current research on rectenna is mainly focused on the integrated antenna coupled with metal-insulator-metal tunneling diodes. Herein, by adopting the plasmon excitation of graphene and quantum tunneling process between graphene and GaAs or GaN, we demonstrated the feasibility of harvesting energy from the 915 MHz wireless source belonging to 5G in the FR1 range (450 MHz–6 GHz) which is also known as sub-6G. The generated current and voltage can be observed continuously, with the direction defined by the built-in field between graphene and GaAs and the incident electromagnetic waves treated as the quantum energy source. Under the RF illumination, the generated current increases rapidly and the value can reach in the order of 10 There are many wireless sensors operating for collecting the data of temperature, sound, vibration, pressure, or motions, which consist of the Internet of Things (IoTs). As powered by small batteries, those widely distributed sensors need to be charged rather than be displaced frequently. Nowadays, electromagnetic radiation generated by Wi-Fi systems of 2.4 and 5.9 GHz  is incre2 semiconducting-metallic phase heterojunction with a cutoff frequency of 10 GHz has been demonstrated [2) graphene/GaAs heterostructure to harvest energy from the 915 MHz wireless source by adopting the direct excitation of graphene hot electrons and fast carrier transportation process [Commonly, we use a rectenna , 4 to hanstrated . Also, anstrated . However process  between  process , extreme process , microsc process , extraor process , and hig process . With el process , which pThe schematic structure of the graphene/GaAs heterojunction shown in σ of graphene is defined as J/E, where J is the current density and E is the electric field. Generally, the overall conductivity is composed by two parts which are the intraband conductivity and the interband one and can be modeled using relaxation time approximation [ħ is the reduced Plank constant, e is the electron charge, kB is the Boltzmann constant, T is the temperature, ω  is the optical frequency, μ is the chemical potential, and τ1  and τ2 are the relaxation times of the intraband and interband scatterings. Through this model, it can be found that at the visible and infrared frequencies, the interband conductivity dominates, and graphene has a constant conductivity of  e2/4ħ. And in the region of 0.1-5 THz, the optical conductivity is decided by the intraband contribution. The real and imaginary parts of the conductivity of the graphene layer are shown in τ1 , has accounted for all scattering mechanisms including carrier-carrier scattering impurity scattering and phonon scattering [τ1  on parameters such as temperature, impurity density, and carrier density. Take τ1 = 0.6 ps, which corresponds to a mobility of 30,000 cm2/Vs for μ = 0.2 eV (carrier density 3 × 1012cm2) [μ = 0.2 eV, τ1 = 0.6 ps, and T = 300 K is shown in ximation , 21:(1)1012cm2) . A typic−1 is very weak, showing that the graphene is of high quality. The G peak locates at around 1588 cm−1, which is blue-shifted comparing to 1580 cm−1 of intrinsic graphene, implying graphene is p-doped after the wet transferring process [e is the value of the electron charge, V is the bias voltage, kB is the Boltzmann constant, parameter n is called the ideality factor, and JsT is the reverse saturation current density which is expressed byA∗ is the effective Richardson constant for thermionic emission [Φbarrier can be deduced from equations  is close to its Fermi level (EF−GaAs). The electrons in the conductance of GaAs tend to transfer to graphene, which moves up the Fermi level of graphene, increases Φbarrier of the junction, and consequently forms a balanced built-in electric field between graphene and GaAs [Φbarrier can be written asχGaAs is the electron affinity of GaAs, ΦGraphene is the work function of graphene, and Δg is the shift of the Fermi level of graphene caused by the electron diffusion [The electronic band diagram of the graphene can be drawn and shown on the left of and GaAs . In suchiffusion , 31. The−9 A at zero bias without 915 MHz RF emission. However, when putting the harvester under the RF illumination, the current increases rapidly more than one order of magnitude and the value can reach in the order of 10−8–10−7 A, which indicates energy generation exited by RF emission. All experiments were conducted in dark conditions shown in We also conducted the experiment under three sources to check whether the DC power caused by different sources will superpose. We placed the device as the center of a circle and two sources at the circle of the radius of 15 cm, forming some different angles as 2O3 between graphene and Si as the insulating layer for carrier transport to obtain better performance of the wireless energy generator. Since the silicon is sensitive to THz, we firstly detect the current it generated with RF emission on and off in order to test whether the silicon is sensitive to 915 MHz or not, which is illustrated in 2O3/Si just like the dark I-V curve of graphene/GaAs mentioned before, which indicates that they are indeed rectifying diodes. AlN and Al2O3 are all insulating layers used for carrier transport layers, which can improve carrier transport efficiency so that the graphene/Si Schottky diode can be optimized. Therefore, there is higher current generated by graphene/AlN/Si and graphene/Al2O3/Si comparing to graphene/GaAs. It is found that the current of graphene/AlN/Si is about 0.25 μA and the current of graphene/Al2O3/Si is 0.2 μA. As shown in Figures 2O3/Si diode can reach as high as 1.3 mV when the RF source is open. Comparing to the voltage that graphene/GaAs generates, graphene/AlN/Si and graphene/Al2O3/Si can greatly optimize the wireless energy generator, which can be seen that the voltage is stable and the value is enhanced. Considering the current generated by electromagnetic wave with different wavelengths, we predict that waves with shorter wave length will harvest larger current. As mentioned before, electrons are excited when photons are significantly greater than bandgap energy. So, the internal carrier emission efficiency is raised when the wavelength gets shorter, thus high frequency and high energy according to the photon energy formula. In this case, it also shows promising application scenarios of the wavelength detector for the wireless source.To further enhance the harvesting efficiency, the device can be fabricated using integrated heterostructure array, which can reduce the parasitic capacitances between graphene and substrate by decreasing the contact area. Instead of a large area, using some small areas in integrated heterostructure array can improve the current density and make the device more solid. Besides, we can adopt the method of inserting an insulating layer between graphene and semiconductor such as GaAs and Si to get higher current density by reducing the charge-carrier recombination. We conducted the experiment of inserting AlN or AlIn summary, we have demonstrated the feasibility of harvesting wireless energy around 1 GHz through a simple graphene/semiconductor heterostructure, which utilizes the unique physical properties of hot electrons of graphene and the ultrafast carrier dynamics between graphene and semiconductor. Moreover, graphene is active for higher frequency wireless energy reaching the scale of THz energy. Therefore, the utilization of the millimeter-wave spectrum to provide power will be one of the most promising ways to support the long-term running of the wireless sensors.


We used two different lateral sizes of graphene, 13 (GN-13) and 28 µm (GN-28). It can be found that the larger sheet sizes of graphene nanosheets give a poorer rate capability. The electrochemical measurements indicate that GN-13 delivers an average capacity of 189.8 mAh/g at 0.1 C and 114.2 mAh/g at 2 C and GN-28 exhibits an average capacity of 179.4 mAh/g at 0.1 C and only 6 mAh/g at 2 C. Moreover, according to the results of alternating current (AC) impedance, it can be found that the GN-28 sample has much higher resistance than that of GN-13. The reason might be attributed to that GN-28 has a longer diffusion distance of ion transfer and the mismatch of particle size between NCM and GN-28. The corresponding characterization might provide important reference for Li-ion battery applications.In this study, we focus on lateral size effects of graphene nanosheets as conductive additives for LiNi Compared to LiFePO4, LiCoxNiyMnzO2, namely NCM-based cathodes, demonstrated much better electrochemical performance, such as higher specific capacity, operating voltage and energy density [0.5Co0.2Mn0.3O2/LiFePO4 core-shell structure. By LiFePO4 coating, the electrochemical performance and safety of the composite are greatly improved by pouch fill cells tests. Yang et al. reported a one-dimensional Nb-doped LiNi1/3Co1/3Mn1/3O2 cathode nanostructure. By Nb doping, the reversible capacity, and structure stability as well as the electronic conductivity and cycle performance of the LiNi1/3Co1/3Mn1/3O2 cathode could be enhanced. The composition-optimized Nb-doped LiNi1/3Co1/3Mn1/3O2 cathode achieved a high discharge capacity of 200.4 mAh·g−1 at 0.1 C. Even at 5 C, the modified cathode still had a high capacity of 118.7 mAh·g−1 after 200 cycles [4 cathode could be dramatically enhanced from 150 to 178 mAh·g−1. For LiCoO2 and Li(Ni1/3Mn1/3Co1/3)O2 cathodes, the maximum specific capacity of 156 and 168 mAh·g−1 were also enhanced by using graphene as a conductive additive. Wang’s group further demonstrated that by adding liquid-exfoliated graphene, the electrode kinetic energy and reversibility of cathodes were greatly enhanced. In addition, graphene-based additives in cathode materials could also shorten Li-ion diffusion paths and reduce polarization in cathode material particles. The liquid-exfoliated graphene used as the conductive additive in cathode materials decreased the content of conductive additive without reducing the electrode conductivity [4 cathode materials. The results indicated that the smallest size of graphene had better electrochemical performance (165 mAh·g−1). The specific capacity and rate performance of LiFePO4 electrodes tend to worsen with increases of the size of graphene, because the length of ionic transport path got longer [The scientific and technological understanding of batteries has been developed rapidly in recent years because of the needs of the electronic devices market. Li-ion batteries are major energy storage devices that are used in many different electronic devices, such as cellphones, watches, computers, etc. . The req4  is one o4 ,4. In or density ,12,13,14 density ,17,18,19 density ,21,22. Z density  proposed0 cycles ,24,25 is0 cycles , of cour0 cycles ,41,42,43uctivity . The resuctivity . The latt longer .0.5Co0.2Mn0.3O2 cathode materials. Graphene and carbon black form three-dimensional structure networks by point-to-plane contact with the graphene and carbon black. The electrochemical measurements indicate that GN-13 delivers an average capacity of 189.8 mAh/g at 0.1 C and 114.2 mAh/g at 2 C and GN-28 exhibits an average capacity of 179.4 mAh/g at 0.1 C and only 6 mAh/g at 2 C, respectively. In this study, we studied the effects of different graphene nanosheets sizes on LiNi0.5Co0.2Mn0.3O2  as the active material, polyvinylidene fluoride (PVDF) as binder and graphene  and carbon black  as conductive additives in the weight ratio 91:4:3:2. Commercial graphene nanosheets (5–10 layers) with different sizes were used in this study. For comparison, two different lateral sizes of graphene nanosheets (denoted as GN-13 and GN-28) were synthesized by using the cavitation process via fixing the chamber pressure at 2000 bar and changing the cycling times to 3 times or 12 times to obtain GN-13  and GN-28 , respectively [The composition of electrodes consisted of LiNiectively . The NCMThe slurry was fabricated as follows: first, polyvinyl difluoride  was added into the graphene (4.6 wt %) suspension in a 10 mL sample vial, stirring smoothly for 2 h by hotplate to make sure the PVDF was fully dissolved. Second, mixing of Super-P (0.02 g) and active material (0.91 g) by powder mixing machine. The Super-P electrode was made in the same method by 5 wt % without adding graphene. Finally, the above mixture was added into N-methyl pyrrolidone (NMP) solution and stirred overnight. The slurry was coated onto aluminum foil (20 μm) by a coating machine and dried in an oven at 80 °C for 30 minutes. The electrodes were punched (Diameter = 14 mm) and dried at 120 °C in a vacuum system overnight to remove the residual water. Electrochemical performance was analyzed by coin cells . 2O and O2 content < 0.5 ppm, using a lithium disk as the counter electrode. The electrolyte consisted of 1 M LiPF6 in ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) (1:1:1 by wt %), with 1 wt % vinylene carbonate (VC). The separators were purchased from Celgard 2325®. The electrochemical performance tests for rate performance  were analysed by an AcuTech System in the voltage window of 3.0 and 4.5 V at room temperature. The electrodes were analyzed by cyclic voltammograms (CV)  in the voltage window of 3.0 to 4.5 V with a scan rate of 0.1~0.5 mV·s−1. Electrochemical impedance spectroscopy (EIS) measurements were measured on Bio-Logic Science Instruments (VSP-300) with a perturbation amplitude of 5 mV at the frequency range between 100,000 Hz and 0.01 Hz.The batteries were assembled in an Ar-gas filled glove box with H50) (50) c. Figure50) of GN-13 and GN-28 were 13 and 28 μm, respectively. The particle sizes (D10) and (D90) of GN-13 were 5 and 28 μm and of GN-28 were 11 and 79 μm, respectively.S, Rf and RCT items in the equivalent circuit. RS is the electrolyte resistance at the highest frequency, Rf is the resistance of the SEI film and RCT is the charge transfer resistance at the middle frequency region. The sloping line represents the diffusion of Li-ion at the lower frequency. Depending on the EIS plot, the RS, Rf and RCT values of GN-13 are 4.14, 123 and 40 Ω, respectively. The RS, Rf and RCT values of GN-28 are 6.13, 142 and 202 Ω, respectively. RCT decreases when smaller graphene is used to be the conductive agent, owing to shorter diffusion length of ionic transfer in the NCM structure. The ionic conductivity of the GN-13 electrode is higher than that of the GN-28 electrode, which indicates that the RCT of GN-13 electrode is smaller than that of GN-28 electrode. The lower slope of EIS analyses have better ionic diffusivity and conductivity. The diffusion length of ionic transfer in the GN-13 based electrode was shorter than that of the GN-28 based electrode. The following equation can calculate the Li-ion diffusion coefficient (D):2), the electrons number involved in the reaction is n (n = 0.75), Faraday’s constant is F (96500 C/mol), and the Li-ion concentration is C (0.001 mol/cm3). −1/2 at low frequency region of GN-13 and GN-28. We calculated the diffusion coefficients of Li-ion in GN-13 and GN-28 to be 4.437 × 10−10 and 4.227 × 10−10 cm2/s by the equation, respectively.+. The curves of both graphene show a similar charge/discharge plateau with the work voltage at 3.0–4.5 V. The diffusion coefficient of lithium-ion in GN-13 and GN-28 can be calculated by the following Randles–Sevcik equation via CV analysis:p (A), the mass of the active cathode material is m, Faraday’s constant is F (96500 C/mol), the ideal gas constant is E (8.314 J/K mol), the room temperature is T, the number of electrons involved in the reaction is n (n = 0.75), the electrode surface area is A (~1.54 cm2), and the concentration of Li-ion is C (0.001 mol/cm3). −8 and 2.61 × 10−8 cm2/s for anodic and 2.16 × 10−8 and 1.8 × 10−8 cm2/s for cathodic reaction, respectively. As shown in In summary, we used graphene nanosheets with different lateral sizes as conductive additives in NCM to study the size effects on their electrochemical properties. An effective electronic conducting network can be constructed and significantly improved the electrochemical performance of NCM by graphene nanosheets and Super P as conductive additives simultaneously. With increased graphene sheet sizes, the specific capacity and rate performance tends to get worse for NCM electrodes due to that the distance of the ion transport path is protracted. Size matching is the critical issue for choosing suitable graphene nanosheets as conductive additives for NCM cathodes for Li-ion battery application. Similar sizing matching of GN and NCM could keep effective balance between fast lithium ion diffusion and increased electron transport.


Blocking the PD-1/PD-L1 pathway can diminish immunosuppression and enhance anticancer immunity. PD-1/PD-L1 blockade can be realized by aptamers, which have good biocompatibility and can be synthesized in quantity economically. For in vivo applications, aptamers need to evade renal clearance and nuclease digestion. Here we investigated whether DNA nanostructures could be used to enhance the function of PD-L1 aptamers. Four PD-L1 aptamers (Apt) were built into a Holliday Junction (HJ) to form a tetravalent DNA nanostructure (Apt-HJ). The average size of Apt-HJ was 13.22 nm, which was above the threshold for renal clearance. Apt-HJ also underwent partial phosphorothioate modification and had improved nuclease resistance. Compared with the monovalent PD-L1 aptamer, the tetravalent Apt-HJ had stronger affinity to CT26 colon cancer cells. Moreover, Apt-HJ markedly boosted the antitumor efficacy in vivo vs. free PD-L1 aptamers without raising systemic toxicity. The results indicate that multiple aptamers attached to a DNA nanostructure may significantly improve the function of PD-L1 aptamers in vivo. Cancer is a leading cause of mortality in the 21st century. There are four main treatments for cancer: surgery, radiotherapy, chemotherapy, and immunotherapy. Unlike the first three treatments that directly target the cancer cells, immunotherapy attacks the tumor through mobilization of the host′s immune system . Among IThe current ICB therapies are implemented by antibodies. There are five monoclonal antibodies targeting the PD-1/PD-L1 pathway approved by the FDA: atezolizumab, nivolumab, durvalumab, avelumab, and pembrolizumab . HoweverAn aptamer is a type of ligand with promising advantages for biomedical applications. Aptamers are short single-strand DNA or RNA oligonucleotides, which can fold into complex 3D structures and bind to target molecules with high affinity and specificity . Compared of 72nM. As a result, the aptamer could bind to murine PD-L1 expressed on CT26 or LL/2 cells, and generate significant tumor inhibition in both CT26- or LL/2-bearing mice, without observable hepatic or renal toxicity [Aptamers have been developed for PD-1/PD-L1 blockade. Lai et al. selected an aptamer for human PD-L1 with relatively high affinity. This PD-L1 aptamer could also bind to recombinant murine PD-L1 protein with a Ktoxicity . The resIt should be noted, however, that for in vivo applications, aptamers need to satisfy certain conditions. Aptamers need to have nuclease-resistance, to a certain degree, in order to survive digestion by serum nucleases. Moreover, aptamers generally have a small size and tend to leach out of the kidney , which uTo date, no report in the literature has evaluated the application of a DNA nanostructure to improve the efficacy of PD-1/PD-L1 blockade by aptamers. In this study, four PD-L1 aptamers were built into the four arms of HJ to form Apt-HJ. Compared with free PD-L1 aptamers, we found that the tetravalent Apt-HJ had stronger affinity to CT26 cells and significantly improved antitumor efficacy in vivo.Previous studies have shown that a PD-L1 aptamer can generate an anti-tumor effect in vivo . In thisIt is well known that the threshold for kidneys to clear nanoparticles is approximately 10 nm . To evalA main obstacle for in vivo application of Apt-HJ is digestion by nucleases, due to the presence of large amounts of nucleases in serum. Various chemical methods have been developed to slow down the digestion of DNA strands by nucleases ,30. Phosd values were also measured and calculated , free PD-L1 aptamers, or Apt-HJ were incubated with CT26 cells, which were subsequently fixed and imaged by confocal microscopy. As shown in It has been reported that CT26 murine colon cancer cells express PD-L1, and that the PD-L1 aptamers can bind with these cells and act as an ICB agent . Since tlculated . The Kd Although Apt-HJ had superior target affinity vs. free aptamers in vitro, it was still unclear whether Apt-HJ would generate antitumor efficacy in vivo. To address this issue, CT26 tumor-bearing mice were treated with PBS, poly-A (control DNA sequence), poly-A-HJ, free PD-L1 aptamers, or Apt-HJ. The treatments were given via intraperitoneal injection every two days, for a total of six injections. The dosage of free PD-L1 aptamers was 1.2 mg/kg. Poly-A treatment had the same molar concentration as free PD-L1 aptamers. Since Apt-HJ and poly-A-HJ were tetravalent, they were given a molar concentration that was 1/4 of the free PD-L1 aptamers, for the sake of fair comparison. As shown in In this study, a new DNA nanostructure (Apt-HJ) comprising four PD-L1 aptamers and a Holliday Junction was constructed to enhance the target affinity and the in vivo antitumor efficacy. Apt-HJ was made of four ssDNA chains which had the PD-L1 aptamer at their 3′ end and the HJ sequence at their 5′ end. These ssDNA chains were assembled into a tetravalent structure via a self-assembly process . The aveA major obstacle for in vivo applications of aptamers is their rapid renal clearance and short circulating time. To address this issue, aptamers are sometimes conjugated to carriers with a high molecular mass to increase their size . PEGylatIn this study, Apt-HJ improved the antitumor efficacy in CT26-bearing mice vs. free PD-L1 aptamers A. The meIn summary, ample evidence has shown that blocking PD-1/PD-L1 pathways can reduce immunosuppression and enhance antitumor immunity. In this study, a novel DNA nanostructure (Apt-HJ) comprising four PD-L1 aptamers and a HJ is constructed. The tetravalent Apt-HJ has higher affinity for tumor cells and improves the antitumor efficacy in vivo. Such multivalent DNA complexes may become a new strategy to further enhance the potential of PD-L1 aptamers in ICB applications.2. DMEM was purchased from the Cell Center of Chinese Academy of Medical Sciences . FBS was purchased from Biond .CT26 (mouse colon cancer cell lines) was obtained from the Cell Center of Chinese Academy of Medical Science . The cells were cultured in DMEM medium supplemented with 10% fetal bovine serum (FBS) and antibiotics (100 U/mL penicillin and 100 μg/mL streptomycin). All cells were incubated in a 37 °C incubator with 5% COAll DNAs were synthesized by Invitrogen . The four DNA strands for Apt-HJ had the following sequences, with the underlined part indicating the sequence of PD-L1 aptamer:ACGGGCCACATCAACTCATTGATAGACAATGCGTCCACTGCCCGT-3′;5′-CGGCGATCCGGCCATAGTGGATTGCGGGCCAGTGAAAAAAACGGGCCACATCAACTCATTGATAGACAATGCGTCCACTGCCCGT-3′;5′-CTCACTGGCCCGCAATCCTGAGCACGTGGCTGACGAAAAAACGGGCCACATCAACTCATTGATAGACAATGCGTCCACTGCCCGT-3′;5′-CCGTCAGCCACGTGCTCACCGAATGCTGCGCAACCAAAAAACGGGCCACATCAACTCATTGATAGACAATGCGTCCACTGCCCGT-3′.5′-CGGTTGCGCAGCATTCGGACTATGGCCGGATCGCCAAAAAThe first nt at the 5′ end of each ssDNA for some Apt-HJ and all polyA-HJ was phosphorothioate modified.2). The concentration of each ssDNA was equal to 4 μM. The mixture was incubated at 95 °C for 5 min and slowly cooled to room temperature at a controlled rate of 0.1 °C/s.Four single-stranded DNA chains were dissolved in a saline solution  agarose and GelStain  in TBE buffer. Samples were loaded onto the gel and run for 30 min at 120 V, and analyzed under UV light. The particle size and zeta potential of the Apt-HJ were evaluated by dynamic light scattering (DLS) using Zeta Sizer Nano ZS90  at 25 °C.The prepared Apt-HJs were verified by using gel electrophoresis. The gel was made by dissolving 2.5%  were incubated in 50% fetal bovine serum (FBS) at 37 °C. At the predetermined time points, the samples were heated immediately at 95 °C for 5 min to inactivate nucleases. Thereafter, electrophoresis was utilized to analyze the degree of Apt-HJ degradation. The gray-scale value was analyzed by Quantity One software .5) were suspended in 250 μL PBS. Next, 60 pmol FAM-labeled poly-A, Apt, or Apt-HJ were added to the cells, which were shaken gently for 30 min at room temperature. The cells were washed thrice with PBS and resuspended in 250 μL PBS. The samples were analyzed directly by Accuri C6 Flow Cytometer . To evaluate the equilibrium dissociation constants (Kd), CT26 cells (2 × 105) were suspended in 250 μL PBS. Next, FAM-labeled Apt, or Apt-HJ were added to the cells. The final concentrations of Apt were 50, 100, 150, 200, 300, 600, 800, and 1000 nM, respectively. The final concentrations of Apt-HJ were 50, 100, 150, 300, 400, 600, and 1000 nM, respectively. Samples were shaken gently for 30 min at room temperature. The cells were washed thrice with PBS, resuspended in 250 μL PBS, and analyzed by flow cytometry . The Kd of PD-L1 aptamers and Apt-HJ was determined by the relationship between the fluorescence intensity and the corresponding concentration [d + X).CT26 cells in a logarithmic growth phase were incubated in PBS (plus 0.02% EDTA) for 30 s and washed gently twice with PBS. The cells  freshly prepared and pre-cooled was applied for 10 min at 4 °C to fix the cells. The cells were washed three times with PBS and stained by Hoechst  for 30 min at room temperature. Finally, cells were washed three times with PBS and incubated with 100 μL PBS. The fluorescence image was analyzed by a confocal laser-scanning microscope .CT26 cells were cultivated in a Lab-Tek Chamber #1.0 Borosilicate Coverglass System  at a density of 1.5 × 105 CT26 cells suspended in 100 μL PBS were injected subcutaneously on the right lower back. After tumor reached to a size of about 5 mm, mice were randomly divided into five treatment groups. The mice were treated with PBS, poly-A, poly-A-HJ, free-Apt, or Apt-HJ via intraperitoneal injection every two days for a total of six injections. The dosage of free PD-L1 aptamers was 1.2 mg/kg. Poly-A treatment had the same molar concentration as the PD-L1 aptamers. Since Apt-HJ and poly-A-HJ were tetravalent, the Apt-HJ or poly-A-HJ treatments were given a molar concentration that was 1/4 of the free PD-L1 aptamers. Tumor size and body weight were measured every 2 days during the experiment. Tumor volume was calculated according to the formula (a × b2)/2, where a and b represent the length and width of the tumor, respectively.Animal study and procedures were approved by the Ethics Committee of Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, according to the institutional animal care and use guidelines. BALB/c mice of 6-8 w old, with an average weight of 20 g, were purchased from Charles River Corp. . To establish a colon cancer model, 5 × 10p < 0.05. Relevant data were presented as mean value and standard deviation.Statistical analyses were performed by GraphPad Prism 8 software. One-way ANOVA with Fisher’s least significant difference (LSD) comparison test was used for statistical calculation. A statistically significant difference was defined as


Sarcoidosis is a systemic granulomatous disease without a known aetiology. Patients can be asymptomatic and do not require treatment. However, for the severe cases of sarcoidosis, anti-tumour necrosis factor-α (TNF-α) agents have been used in addition to corticosteroids and disease modifying anti-rheumatic drugs (DMARDs). Paradoxically, anti-TNF-α treatment has also been shown to induce sarcoidosis in patients with autoimmune diseases, though what is known about the pathogenesis of this phenomenon is limited. We present a case of renal sarcoidosis occurring following Certolizumab Pegol (CZP) treatment in a patient with psoriatic arthritis.A 55-year-old Caucasian man presented to the emergency department in Jan 2020 with a seizure and was found to have a stage 3 acute kidney injury. He was diagnosed with psoriatic arthritis (PsA) at age 47 and plaque psoriasis at 20. He has no other past medical history. For PsA, he was initially treated with Methotrexate, but this was stopped due to nausea. After failing on sulfasalazine, he was started on Humira  and low dose Methotrexate, 10mg weekly. Due to lack of efficacy, he switched to Benepali (Etanercept) monotherapy. One year later, he was switched to Cimzia (Certolizumab Pegol) due to worsening disease activity. He was on the treatment for 7 months before presenting with seizures and renal failure. His seizure was caused by uraemia and hypertension secondary to renal failure. He has severe renal dysfunction (eGFR of 8ml/min/1.73m2), but low-level proteinuria (uPCR of 47mg/mmol). A renal biopsy was performed which showed features of non-necrotising interstitial nephritis, with well-formed granulomas & multiple giant cells, consistent with renal sarcoidosis. Infections were excluded including TB.2) on admission to 526µmol/L (eGFR 10ml/min/1.73m2) on discharge a week later. He did not require renal replacement therapy during admission. The dose of prednisolone was tapered over time, he is now on 10mg per day and his creatinine in April 2020 was 344 µmol/L, (eGFR 16 ml/min/1.73m2).He was started on high dose prednisolone 80mg daily, a modest improvement in creatinine was observed from 636µmol/L (eGFR 8ml/min/1.73m2), his prednisolone was reduced further to 5mg daily.Currently, his psoriatic arthritis is under control, and his latest creatinine in July was 293 µmol/L  associated with onset of sarcoidosis, this is one of the treatment options for psoriatic arthritis and psoriasis as per NICE guidance (TA445). Tofacitinib has been approved by NICE recently (TA543) for PsA, so far, there are no case reports associated with the onset of sarcoidosis, rather, it has been used to treat sarcoidosis successfully. Therefore, Tofacitinib seems to be a potential treatment option for this patient.Certolizumab-induced sarcoidosis is a rare but increasingly recognised phenomenon.The role of anti-drug antibodies in the pathogenesis of anti-TNF-α agent-induced sarcoidosis remains unclear.Systemic corticosteroid treatment seems to be an effective treatment for anti-TNF-α agent-induced sarcoidosis.Tofacitinib has not been reported to cause drug-induced sarcoidosis and is a viable alternative treatment option.Key learning points therefore include: