After the continued failure of β‐secretase (BACE1) inhibitor clinical trials in prodromal as well as mild‐to‐moderate Alzheimer's disease (AD), they are shifting to further earlier or asymptomatic stages. The aim of this study is to explore a cognitive paradigm that allows us to more sensitively detect beneficial effects of BACE1 inhibitors in presymptomatic AD.GRL‐8234 , a small‐molecule BACE1 inhibitor, was administered once daily for 28 days to the 5XAFD transgenic mouse model of AD. The contextual fear conditioning was used to evaluate the effects of GRL‐8234 on memory deficits in 5XFAD mice at different ages.Chronic administration of GRL‐8234 to 5XFAD mice rescued their contextual memory deficits, when tested 1 day after training at 6‐8 months but not at 12 months of age. Importantly, 4‐month‐old 5XFAD mice retain the ability to form contextual memory equivalent to wild‐type controls, demonstrating that the standard method of 1‐day memory assessment is not suitable for evaluating BACE1 inhibitor efficacy in ameliorating cognitive declines during earlier disease stages. Despite normal contextual memory formation, young 5XFAD mice showed faster forgetting when a longer delay (28 days) intervened between training and memory testing. Notably, GRL‐8234 administered to 4‐month‐old 5XFAD mice during the 28‐day delay reversed accelerated long‐term forgetting almost completely back to wild‐type control levels.The results provide experimental evidence that accelerated long‐term forgetting represents more sensitive memory testing that can help evaluate BACE1 inhibitor therapy in presymptomatic AD populations. Despite intact 1‐day contextual memory, 4‐month‐old 5XFAD mice showed faster forgetting when a longer delay (28 days) intervened between training and memory testing. Notably, accelerated long‐term forgetting was reversed by the BACE1 inhibitor GRL‐8234 administered during the 28‐day delay. Therefore, accelerated long‐term forgetting represents a sensitive paradigm that can detect subtle cognitive decline and help evaluate early BACE1 interventions during presymptomatic stages of Alzheimer's disease. Data were presented as mean ± SEM, and the level of significance was set at 33.1P < .05). GRL‐8234 significantly increased contextual freezing in 5XFAD mice at 6‐8 months of age (P < .05), restoring the impaired 1‐day memory completely back to wild‐type levels  at ~ 6 months concomitant with moderate Aβ accumulation and the onset of Schaffer collateral‐CA1 synaptic dysfunction.s Figure . In conts Figure . Togethe3.2P < .05), while GRL‐8234 administered during the 28‐day delay reversed accelerated long‐term forgetting in 5XFAD mice almost completely back to wild‐type control levels (P < .05)  Figure . The res4Consistent with our previous findings in the spontaneous alternation Y‐maze task,More importantly, the standard procedure of 1‐day memory assessment was not sensitive enough for detecting subtle declines in the contextual fear conditioning in 4‐month‐old 5XFAD mice, while a longer delay (28 days) intervening between training and memory testing revealed accelerated long‐term forgetting that was reversible with chronic administration of GRL‐8234. Consistent with our findings in young 5XFAD mice,−/− knockouts.+/– reduction or the lower dose of inhibitors devoid of synaptic side effect.A growing number of BACE1 substrates besides APP uncover new physiological roles of this protease,The author declares no conflict of interest.MO designed the research, performed the experiments, analyzed the data, and wrote the manuscript.All animal experiments were approved by the Animal Care and Use Committee of Nathan Kline Institute.Table S1Click here for additional data file.


During the 2020 SARS-CoV-2 pandemic, physical distancing and mask use guidelines were implemented resulting in a decline in the number of infections caused by influenza, respiratory syncytial virus and otitis media. A surveillance analysis from England and Taiwan showed a decline in invasive pneumococcal disease (IPD) . We hypothesized that COVID mitigation efforts resulted in a decrease in incidence of pediatric IPD within the U.S. during 2020 compared to previous years.Streptococcus pneumoniae from normally sterile sites . Pneumococcal pneumonia was defined as an abnormal chest radiograph in the presence of a positive blood, pleural fluid or lung culture. Mastoiditis was identified by positive middle ear, subperiosteal abscess or mastoid bone culture. Serotypes were determined by the capsular swelling method. Hospital admission numbers were obtained for incidence calculations. Statistical analyses were performed using STATA11. A p< 0.05 was considered significant.We reviewed all cases of IPD among 7 children’s hospitals from the U.S. Pediatric Multicenter Pneumococcal Surveillance Group from 2017-2020. IPD was defined by the isolation of A total of 410 IPD cases were identified. The cumulative incidence of IPD (0-22 years of age) decreased from 99.2/100,000 admissions in 2017-2019 to 53.8/100,000 admissions in 2020 . Pneumococcal bacteremia and pneumonia decreased significantly in 2020 (p< 0.05), and although not statistically significant, there were fewer cases of meningitis and mastoiditis when compared to previous years (p=0.08) . Sex, race, age or presence of comorbidities were not significantly different between groups. Most common serotypes in 2020 were 35B, 3 and 15B/C .S. pneumoniae via droplets and viral infections frequently preceding IPD. These precautions might be useful in the future to decrease IPD, especially in high-risk patients.The observed decline in IPD cases during the first year of the SARS-CoV-2 pandemic is likely associated with mask use and physical distancing limiting transmission of Sheldon L. Kaplan, MD, Pfizer (Research Grant or Support) Tina Q. Tan, MD, GSK  Involved: Self): Advisor or Review Panel member, Grant/Research Support; ILiAD  Involved: Self): Advisor or Review Panel member; Merck  Involved: Self): Advisor or Review Panel member, Grant/Research Support; Moderna  Involved: Self): Advisor or Review Panel member; Pfizer  Involved: Self): Advisor or Review Panel member Pia S. Pannaraj, MD, MPH, Pfizer (Grant/Research Support)Sanofi-Pasteur (Advisor or Review Panel member)Seqirus (Advisor or Review Panel member) Larry Givner, MD, AstraZeneca (Advisor or Review Panel member) Kristina G. Hulten, PhD, Pfizer (Research Grant or Support)


X-ray photoelectron spectroscopy analysis confirmed that the graphene precursors, as well as the coatings, contained typical nitrogen groups, such as pyridinic and pyrrolic, and sulfur groups, such as thiol, thiophene, or C-SO2. However, due to oxidation during deposition, the qualitative and quantitative composition of the graphene coatings changed relative to the composition of the precursors. In particular, the concentration of nitrogen and sulfur dropped and some thiophene groups were oxidized to C-SO2. Studies showed the functionalized coatings had a uniform, defect-free, hydrophobic, more adhesive surface than nonmodified films. The corrosion measurements demonstrated that these coatings had better protective properties than the ones without these heteroatoms. This behavior can be assigned to the catalytic activity of nitrogen towards oxidation of C-SO2 groups to C-SO3H with oxygen.Electrophoretic production of anticorrosion carbonaceous coatings on copper could be successfully performed by anodic oxidation of negatively charged graphene platelets suspended in an aqueous solution. The various platelets were synthesized by Hummer’s method followed by a hydrothermal reduction in the presence of NH Nevertheless, the coatings probably contain a number of intact graphene domains, which might be current conductive. One can visualize such coatings as the one composed of three domains: pure graphene (current-conducting), oxidized graphene , and defects or holes that do not protect the metal surface. Once graphene oxide is employed as the EPD precursor, we end up with coatings that do not meet the criteria of good protective properties [2 to SO3 over N-doped graphene [2 to C-SO3H with oxygen (from the air) penetrating the N-doped graphene coatings. As a matter of fact, this reaction also involves oxygen reduction, but the electrons are donated by sulfur not metal, thus it may diminish corrosion.Graphene and its various oxidized or chemically functionalized forms have been recently studied as monolayers or multicomponent coatings for corrosion protection of metals. Graphene possesses properties that are beneficial for metal protection, such as chemical resistance, mechanical endurance, good adhesion to metals, or impermeability to gases and water. On the other hand, the conducting graphene layers might accelerate the corrosion in some instances . Moreoveposition . This isoperties ,11,12. Toperties . In turnoperties . Howeveroperties , which toperties . Indeed,graphene ,18. We hNitrogen- and sulfur-functionalized reduced graphene oxide coatings as the anti-corrosion layer have not been reported yet. In the present work, graphene oxide, reduced graphene oxide, and nitrogen- and sulfur-functionalized reduced graphene oxide were synthesized by an improved Hummer’s method, one-step hydrothermal method, and one-step hydrothermal method in presence of ammonium thiocyanate, respectively. Subsequently, the obtained products were electrophoretically deposited on the copper substrate and subjected to numerous studies, revealing their properties.4, purity: 99.0%, POCH, Gliwice, Poland), orthophosphoric acid , sulfuric acid , hydrogen peroxide , ethanol , hydrochloric acid , acetone ((CH3)2CO, POCH), ammonium thiocyanate , and sodium chloride  were used. Copper sheets , graphite powder , potassium permanganate . At the end, the precipitate was washed with acetone, which was then evaporated, leaving around 1 g of a brown solid.Graphene oxide was synthesized by the improved Hummer’s method . ConcentThe one-step hydrothermal method was used for the preparation of reduced graphene oxide . In tota4SCN  were dispersed in 40 mL of distilled water by using an ultrasonic bath for 30 min. Then, the mixture was put into a stainless steel autoclave heated to 180 °C for 6 h. Afterwards, the solid was filtered under vacuum, washed several times with distilled water, and dried at 60 °C for 24 h.Nitrogen- and sulfur-functionalized reduced graphene oxides  were prepared by the one-step hydrothermal method in the presence of ammonium thiocyanate . GO  analysis was performed with Rigaku MiniFlex 600 in the range of angle 2°–90° . Characteristic crystallographic parameters such as an interlayer distance (d002), an in-plane crystallite size (aL), and an average crystallite width (cL) were calculated using the following equations: λ—radiation wavelength (Å); θ1—(0 0 2) diffraction peak position (°);θ2—(1 0 0) diffraction peak position (°); FWHM—width at half height of the corresponding diffraction peak (rad).All functionalized precursors of coatings were prepared from newly synthesized graphene oxide. Results for GO and rGO are meant to be reference data. Fourier Transform Infrared Spectroscopy (FTIR) of precursors of the coatings was conducted on the spectroscope PerkinElmer Frontier over a scanning range 550–4000 cmD/IG was calculated as the quotient area under the D peak and under the G peak. As a result of the deconvolution of bands, the area under peaks was obtained. X-ray photoelectron spectroscopy (XPS) analysis was prepared by the Omicron NanoTechnology system at a pressure below 1.1 × 10−8 mBa and at room temperature. The Argus hemispherical spectrometer with a 128-channel collector was used for the energy measurement of photoelectrons. The photoelectrons were excited by a Mg-Kα X-ray source operated at 15 keV and 300 W. Analysis of obtained results was performed using CASA XPS software package with Shirley background subtraction and least-square Gaussian–Lorentzian—GL(30) curve fitting algorithm. Calibration of measured spectra to the binding energy of 285 eV for the C1s line was conducted. Zeta potential measurements of the graphene sheets in aqueous suspensions were carried out by using Malvern Zeta-Sizer. A contact angle of the coatings was determined by the goniometer Cam 200 KSV. The used liquid was distilled water (dosing volume of water of 1 µL). The surface topography of layers was defined by the Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM). SEM images before the electrochemical tests were collected on the microscope Quanta FEG 400-FEI Company , whereas SEM images after electrochemical tests and thickness of the coatings were obtained by SEM Microscope FEI Quanta FEG 250 with a SE-ETD detector (secondary electron—Everhart-Thornley detector), using 10 kV beam accelerating voltage. Film thickness is the average value of all thickness measurements of the layers. AFM images were obtained using Bruker Catalyst by noncontact mode using Au coated silicon tips (scan rate—0.273 Hz). The cross-cut test was used to determine adhesion between the graphene coating and the metal substrate. With a knife, cuts separated by about 1 mm were made on the surface of coatings. After an adhesive tape was broken, on the basis of the number of detached graphene flakes, the adhesion of coatings was determined.Raman spectra were recorded on Horiba-Jobin Yvon microprobe apparatus excited by a 532 nm laser. A ratio of I−1. To stabilize potential, every sample was immersed in the solution for 30 min before measurement.A sodium chloride solution (3.5% NaCl) was used as the corrosive medium. Chloride ions are very aggressive for the copper substrate; therefore, it is important to assess the durability of the coatings in this environment. For evaluation of the protective properties of the graphene coatings, a potentiodynamic polarization was applied. Measurements were carried out by using a potentiostat, ATLAS-SOLLICH 0531 (Poland), connected to a cell containing the coated copper substrate as a working electrode, an Ag/AgCl (KCl saturated) reference electrode, and a platinum wire as a counter electrode. Electrochemical tests were performed twice for each sample, in a potential range of −0.1 to 0.1 V  with a scan rate of 0.5 mV scorrE) and corrosion current density (corrI) were determined from the intersection of the anode and cathode curves. Corrosion rate (CR) was calculated from the following equation (ASTM G59):K—corrosion rate constant (mm year−1);corrI—corrosion current density (µA cm−2);EW—equivalent weight, for Cu 31.7 g;d—density, dCu = 8.97 g cm−3.Corrosion potential . The stretching energy of 1500 cm−1 is completely missing for GO , the strong band at 1500 cm−1 shows up  was estimated from the width of (1 0 0) reflections at ca. 43°, while the stacking number of graphene sheets (Lc) was estimated from the width of (0 0 2) peaks at ca. 26°  [The elemental compositions of the studied graphene precursors and coatings were studied by the XPS technique . The higx = 2,3) . 2 hybridization of the carbon atoms . During electroformation of the coatings, many thiophene and thiols were oxidized to carbon bound –SO2 groups, although some sulfur was lost due to SO2 gas release.The percentage chemical compositions of the precursors and coatings are presented in Electrophoretic deposition requires stable dispersions. Due to the large interlayer distance for graphene oxide maintained by weak interactions, the stable suspension of graphene oxide was easily produced by 0.5 h treatment in an ultrasonic bath. Reduced graphene oxide samples were characterized by significantly lower interlayer spacings and thus, stronger interactions between layers. This caused the obtention of uniform suspension more difficult, simultaneously contributing to prolonged ultrasonic treatment (around 2 h). The obtained suspensions were stable due to the Zeta potential (ζ) being lower than −30 mV . Measure2 groups. Moreover, an increase in the potential from N,S-rGO300 to N,S-rGO600 samples results from the increasing content of graphitic nitrogen , whose positive charge compensates the negative charge of C-SO2 groups.As expected, the Zeta potential for rGO is higher (less negative) than that for GO. However, in the case of functionalized graphene oxide samples, the Zeta potential is much lower than that for GO and rGO due to the presence of the C-SO2 release during electrolysis. The other precursors were not subjected to the destructive CO2 evolution because they contained a substantially lower concentration of oxygen in their structures. The same observation is also true for the functionalized coatings. The roughness of the coatings was estimated by the AFM . The resThe low wettability of the protective coatings is a crucial property to fend off water. The measured contact angles show  that allSEM images of all coatings, before and after electrochemical studies, are presented in The corrosion resistance of all coating against 3.5% sodium chloride solution was tested by a potentiodynamic polarization method. The results are presented by the Tafel plots in corrE shifted towards more positive values for all coated samples, indicating that coatings probably act as a barrier separating copper from the aggressive environment. However, the hydrophilic nature of the graphene oxide allows penetration of the GO coatings by water, causing oxidation of copper. Moreover, the high current density stems also from the partial or complete oxidation of carbon, which may finally result in the decomposition of the coatings.As can be seen in In the case of the rGO coatings, their hydrophobicity makes them an impenetrable water barrier. Therefore, the measured corrosion current stemmed only from the oxidation of carbon. Thanks to this, the surface of these coatings became smoother after the electrochemical tests.2 groups formed as a result of the oxidation of thiophene groups during EPD. Nitrogen that is also present in the structure can effectively catalyze the oxidation of these groups to C-SO3H by oxygen from the air, so oxygen can no longer depolarize the copper metal. The corrosion protection mechanism of the graphene coatings is presented in In our previous work, we showed that the nitrogen-functionalized graphene oxide coatings had protective properties, but these were comparable to the anticorrosion properties of the reduced graphene oxide coatings. Nitrogen groups exhibiting catalytic properties towards the oxygen reduction reaction were responsible for this behavior. The coatings produced in this study contain a substantial amount of C-SO2 groups in their structures, which formed as a result of the oxidation of thiophene groups. Nitrogen can effectively catalyze the oxidation of these groups to C-SO3H with oxygen from the air. The introduction of nitrogen and sulfur groups to the graphene oxide structure contributed to the improved corrosion resistance of graphene coatings produced by EPD on the copper substrate. These coatings had numerous C-SO


Blended cognitive-behavioural therapy (bCBT) combines face-to-face CBT (FtFCBT) and Internet-based CBT (iCBT) into one integrated treatment protocol, opening up new ways to deliver therapy, increase cost-effectiveness and resolve scarcity of therapist availability. When traditional therapy is transformed into a new format, there is a need to evaluate whether principles of the new protocol are consistently applied.N = 44) received bCBT within a randomised controlled trial. Ratio of FtF to online sessions, session frequency and therapist adherence to instructions were assessed.This study aimed to explore therapist fidelity to bCBT protocols for anxiety disorders in specialised mental health care and to assess whether fidelity is related to patient characteristics. Adult patients , as well as patient computer experience . Adherence to instructions in FtF sessions was based on a subset of patients (n = 23) and should therefore be interpreted with caution.Overall therapist fidelity with regard to ratio of blending, session frequency and instructions was high. Correlations were found between patients' share of online sessions and both session frequency (The blended approach was generally delivered as intended, indicating that the format is feasible in specialised mental health. •Therapist fidelity to blended cognitive behavioural therapy protocols for severe anxiety disorders was high.•Treatment of higher intensity had a higher share of online sessions.•Patients with more computer experience were likely to receive higher shares of online sessions.•Results support feasibility of the blended approach in specialised mental health care.•Results enhance confidence in earlier findings on effectiveness and cost-effectiveness of blended cognitive behavioural therapy for severe anxiety disorders. Patients in both groups reported high levels of treatment satisfaction, and both conditions yielded large within group effect sizes at posttest and at one-year follow-up. A small RCT (N = 36) of bCBT for panic disorders by another research group achieved results in line with our findings regarding acceptability and effectiveness, with medium to high effect sizes in both treatment groups and no differences in treatment satisfaction between the groups  is an effective psychological treatment for anxiety disorders . Internee groups .Blended interventions appear increasingly popular as treatment protocols for blended therapy become more widely available . HoweverN = 36) pointed to a lack of clear guidelines on incorporating online sessions as a major barrier to providing bCBT.The degree of treatment fidelity is important not only for understanding effectiveness and cost outcomes, but it also provides essential input for developing therapist guidelines on how to use bCBT . In a reN = 495) (N = 39)  were rated in terms of therapist adherence to the CBT protocol, with mean scores emerging of 85% on a 0%-to-100% scale (SD = 10.4) and 6.18 (SD = 0.51) on a 1-to-7 scale. Concerning Internet-based CBT, Hadjistavropoulos and colleagues investigated adherence to feedback instructions in online feedback messages   or videomessages . They ramessages  therapisn = 250) trained and equipped to use bCBT actually offered a treatment containing both FtFCBT and iCBT to their patients. Furthermore, they used iCBT as an add-on rather than a replacement of FtF sessions. In a qualitative study on barriers and facilitators of bCBT  therapists (n = 5) stated that they lacked knowledge on how to integrate online components in FtF therapy and in a study on patient experiences with bCBT (n = 15), a deficiency in the interplay between FtF and online components and a lack of therapist awareness of patient activities in online sessions was found to be a cause of patient dissatisfaction  or FtFCBT (n = 62) in one of four Dutch outpatient clinics for specialised mental health care between November 2015 and July 2017. Written informed consent was obtained from all participants before baseline assessment and randomisation. Participants were informed that participation in the trial was not contingent upon agreeing to be audio-recorded. A separate consent document for permission to record was obtained. A total of 45 patients started the bCBT treatment. Since one patient dropped out after the first session, our study of treatment fidelity analyses data from the 44 participants who actually received bCBT. The trial was approved by the Medical Ethics Committee of the Amsterdam University Medical Centers, location VU University Medical Center (registration number 2015.073) and registered in the Netherlands Trial Register (NTR4912).Data were collected within an RCT assessing the clinical and cost-effectiveness of bCBT in comparison with FtFCBT . In that2.2www.minddistrict.com). Patients and therapists accessed this platform with a personalised login. The online sessions offered information (videos and text), testimonials from fictional patients, assignments  and homework exercises . Therapists provided feedback on assignments and homework exercises. Default text templates for feedback and instructions were supplied for every online session as a therapist aid for providing feedback as intended. Therapists were free to tailore these texts to the specific needs of their clients. The online treatment platform also offered the option of repeating an online session. Therapists could decide on that if they deemed it beneficial, for example if the patient had not fully comprehended the content of an online session or had greatly benefited from a specific exercise in it.Separate manualised bCBT protocols were developed for patients with panic disorder, social anxiety disorder and generalised anxiety disorder . Their content was based on protocols for FtFCBT , which contain evidence-based elements for the treatment of anxiety disorders, such as cognitive therapy and exposure  see . In all 2.3Patients were invited for study participation if they (i) were aged 18 or older and (ii) met the DSM-IV criteria for panic disorder with or without agoraphobia, social anxiety disorder or generalised anxiety disorder, as diagnosed with the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I ) or the 2.4Therapists were trained and experienced in delivering CBT. Prior to treating patients in the trial, all therapists received a 2-h training course in the delivery of the blended treatment protocol, provided by researcher GR. During the training, therapists received instructions on how to apply the blended format, and were shown the main sections and functionalities of the online platform such as the start page of the therapist portal and entry point to other sections of the platform, treatment modules, homework area, feedback templates and messaging function. They also had the chance to practise with a fictitious patient. In addition, discussion sessions were organised by the research team in which therapists could exchange their experiences with bCBT.2.5Information on patient characteristics was obtained via an online self-report questionnaire at baseline. Primary diagnosis and comorbid disorders were established by a diagnostic interview .2.7The bCBT protocol prescribed weekly sessions. Session frequency was determined by dividing the total number of completed FtF and online sessions by the total therapy duration in weeks (session frequency = (number of completed FtF sessions + number of completed online sessions) / duration therapy in weeks)).2.8p < .001, 95% CI 0.86–0.93) and for online components 0.90 , indicating good agreement between the raters with respect to both FtF and online sessions.To assess fidelity to the blended protocol in the FtF sessions and the online sessions, we developed a checklist based on the treatment protocol, containing the mandatory blended protocol components  were used to describe the sample and the observed fidelity. The relationships between fidelity scores and patient characteristics were assessed with Pearson correlations. Analyses were undertaken using SPSS, version 23 .33.1A total of 44 patients were given bCBT by 28 therapists. Baseline demographics and clinical characteristics of the patient sample can be found in 3.2n = 29) contained 50% to 60% FtF sessions. In fourteen cases (32%), the share of FtF sessions was either 40% to 50%  or 60% to 70% ; in two cases (5%) it was higher than 70% (75% and 80%).The mean treatment duration was 12.6 sessions (SD: 5.2), with 6.7 FtF sessions (SD: 2.6) and 6.0 online sessions (SD: 2.9) in 15.6 weeks (SD: 8.7). The mean percentage of FtF sessions in the 44 courses of blended treatment (55%) was almost equal to the prescribed 53%. Most courses of treatment , slightly lower than the 1.0 sessions per week as prescribed. Five courses of treatment (11%) had a frequency of exactly 1 session per week, in 13 cases (30%) frequency was higher (range: 1.1–1.4) and in 26 cases (59%) frequency was lower (range: 0.3–0.9).r = 0.373, p = .013), suggesting that patients who received a larger share of online sessions were likely to have higher-frequency treatment than those receiving more FtF sessions.Session frequency was higher  when the ratio of online to FtF sessions was positive than when the ratio of FtF to online sessions was positive . The correlation between session frequency and the FtF-to-online ratio was significant , therapists forgetting to record sessions, poor recording quality and low battery of the recording device. Forty-six (62%) recorded sessions were conducted in full accordance with the blended instructions in the protocol, while in 28 sessions (38%) some devations to the protocol occurred  sessions received by 23 patients. There were no significant differences in baseline characteristics  between the patient sample that consented with recordings and the patient sample that did not consent with recordings. The recorded sessions were provided by 17 therapists, of whom 15 were female (88%), 10 (59%) were licensed health care psychologists and 7 (41%) were supervised psychologists in training for health care psychologists. Reasons for non-availability of recordings included: participants not consenting to be recorded , therapists deviated from the protocol where the previous online session should have been discussed (Boxes 2a and 2b). In one case the online session was not mentioned at all; in other cases therapists did refer to it, but there was little or no discussion of homework and assignments.n = 20). In the other two cases, therapists did not discuss the homework for the upcoming online session.Most deviations from the protocol occurred when the upcoming online session was to be discussed (Box 3). In 22 of 66 sessions (33%), therapists deviated from the instructions, mostly by not scheduling an appointment for providing feedback on the next online session  of the 257 online sessions were repeated. Feedback messages on repeated sessions were usually short and practical in nature (Boxes 5a to 5c) and usually did not contain CBT-specific feedback (31 of 34 messages).3.5r = −0.314, p = .038), indicating that the treatment of patients more experienced with computers was likely to contain a larger percentage of online sessions. No significant associations between other patient characteristics and fidelity outcomes were found.44.1The aim of this paper was to explore therapist fidelity to bCBT protocols for anxiety disorders in specialised mental health care, considering insights in the actual application of blended treatment are lacking. Additionally, we wanted to gauge the influence of patient characteristics on bCBT fidelity, since therapists believe some patients are better suited for bCBT than others .g by 0.45, with the total number of sessions held constant.Overall, therapist adherence to the instructions in the blended treatment protocol was high. The mean session frequency was 0.89 sessions per week (SD: 0.26), slightly lower than the 1.0 sessions per week as prescribed. The ratio of FtF to online sessions was negatively associated with session frequency, suggesting that a larger share of online sessions enables a higher treatment frequency. This may be relevant in the light of meta-analytic findings by Cuijpers and colleagues  showing Our inspection of patient characteristics showed a significant association between the ratio of blending and patient experience with the use of computers, indicating that those with more computer experience were more likely to receive a higher share of online sessions. Other patient characteristics, such as pretreatment anxiety severity or comorbidity, were not associated with fidelity outcomes. This finding is in line with previous findings for FtF therapy  and refu4.2Evaluating fidelity is a time-consuming process, and it becomes even more complex when two treatment modalities are integrated into one treatment protocol. For this reason, treatment fidelity is often not examined in intervention studies, and had not yet been evaluated for blended treatment at all, even though it is essential to the interpretation of treatment outcomes and to successful implementation of a blended format. As this study was an investigation of therapist fidelity to a blended treatment protocol assessing both the FtF and the online elements of the treatment, we were able to examine what actually happened during blended treatment: did it blend?It should be taken into account that the current analyses into fidelity were explorative in nature and should be seen as one of the first steps in unravelling the application of blended treatment. Although findings on blending ratio, session frequency and adherence to protocol instructions in online sessions were based on the full patient sample, results regarding the adherence to instructions in FtF sessions were based on a subsample of patients and a subset of therapy sessions. Even though characteristics of this subsample of patients resembled the full sample, we cannot be sure whether the recorded sessions were representative of all FtF sessions, which is a clear limitation of the study.Furthermore, comparing our results to other studies, and comparing outcomes on treatment fidelity in general, is complicated by the lack of uniformity in the definition of fidelity used by different authors. One general definition is: ‘the degree to which a treatment is implemented as it was intended in the original protocol’; however, more specified definitions vary across studies and varying interpretations of the concept hinder shared understanding of findings . The cur4.3Opportunities to improve therapist fidelity to the blended treatment format appear to lie in enhancing therapist recognition of FtF and online sessions as equally important elements of treatment. If that is not acknowledged, online sessions cannot adequately replace FtF sessions. In the current study, therapists often did not set a date to provide feedback on online sessions, which could be an indication that a therapist sees those sessions as merely supportive to the FtF sessions and this idea can uncounsiously be transferred to the patient. This requires attention in training therapist. Furthermore, if an appointment calendar function were added to the online platform, that might improve fidelity to this protocol component and heighten therapists' awareness of the importance of online elements in blended treatment.Previously, a lack of clear guidelines has been identified as a barrier to the use of bCBT . In someOne benefit of a blended format, as found in earlier studies, is that it can enhance therapists' adherence to the treatment protocol . In the Finally, an interesting topic for subsequent research would be whether therapist variables are associated with the degree of treatment fidelity. Identifying therapist characteristics that predict fidelity to bCBT could assist mental health care services in the selection and training of professionals.5Our findings suggest that the blended treatment was generally conducted as intended, indicating that delivery of bCBT in the applied format is feasible for therapists in specialised mental health care. This enhances confidence in the findings on effectiveness and cost-effectiveness of bCBT reported elsewhere : high trThe current study was conducted prior to the coronavirus crisis. The outbreak of a pandemic disease highlights the relevance of online treatment as an important element of routine care practice . BlendedProtocol components with instructions regarding the blended format.Supplementary Table 1Patient characteristics.Supplementary Table 2n = 74 recorded sessions).Adherence to protocol instructions in face-to-face sessions (Supplementary Table 3n = 257 sessions).Adherence to protocol instruction in online sessions .Correlations of patient characteristics with treatment fidelity outcomes (Supplementary Table 5Content of the sessions in the bCBT protocol.Appendix 1Checklist for fidelity to bCBT treatment protocol, including examples.Appendix 2Examples of full and partial adherence to blended instructions in FtF sessions and online feedback messagesAppendix 3The following are the supplementary data related to this article.The authors report no conflicts of interest related to this publication.


However, monolayer graphene still suffers from defects that cause leakage. Here, we report a method of sealing defects in graphene transferred onto porous polymer substrate via reduced graphene oxide (rGO). The influence of various reducing agents  on the properties of rGO was investigated by SEM, Raman, FTIR, and XRD. Subsequently, membranes based on graphene/reduced graphene oxide were tested in a forward osmosis system using sodium chloride (NaCl). The effect of the effectiveness of the reduction of graphene oxide, the type and number of attached groups, the change in the distance between the rGO flakes, and the structure of this material were examined in terms of filtration efficiency. As a result, semi-permeable centimetre-scale membranes with ion blocking efficiency of up to 90% and water flux of 20 mL h The rapid growth of the human population, industrialisation, and climate change have a great impact on decreasing water supplies. Along with the continuous release of pollutants into water such as microplastic, heavy metals, dyes, etc., these have caused over one billion people over the world to suffer from drinking water shortage . For thiThe desire to develop a membrane with the smallest possible thickness, and thus, to obtain the lowest flow resistance, has prompted researchers around the world to work on the use of graphene and related materials for this purpose. Apart from the thickness of one atom (the thinnest possible active part of the membrane), the main advantages of graphene are its strength, flexibility, chemical, and thermal properties. Graphene, in its ideal form, cannot be used as a filtration membrane because it is impermeable even to atoms as small as helium , and, th® can be listed. Quasi-monocrystalline HSMG® graphene is produced by the metallurgical method on a substrate of liquid copper [Among the methods of synthesis of large-area graphene methods like CVD on liquid copper, CVD on solid copper, and HSMGd copper ,12. The ®). Despite the development of the mentioned transfer methods, cracks and defects still appear at this stage and must be eliminated in the next steps of membrane production.The production efficiency of graphene membranes and their size are largely limited by the difficulty of obtaining large, continuous, and undefective graphene layers on mainly copper and nickel substrates. The synthesis of large-area graphene and its transfer to the support substrate determine the purity and quality of the produced membrane. Currently, the most used method of graphene transfer is a wet transfer, in which graphene is coated with a carrier polymer and then the graphene growth substrate is etched with appropriate reagents. A competitive method for wet transfer is electrochemical delamination, in which graphene is also coated with a carrier polymer, and then in the electrolyte, under the influence of the applied voltage, is separated from the substrate due to the hydrogen generated between the growth substrate and graphene ,14. It i® graphene sealed with reduced graphene oxide or nylon manufactured on polymer scaffoldings revealed semi-permeable properties in FO filtration mode. The clue of this solution was sub-nanometre pores in the graphene layer structure. The effectiveness of the graphene membrane depends on how it is sealed. Using graphene oxide for this purpose may be of key importance [Currently, RO and FO membranes based on various graphene materials are being developed and tested. The active layers of such membranes are for example graphene monolayers, graphene multilayers, graphene monolayers sealed with polymer materials, layers of graphene oxide, and reduced graphene oxide applied by various methods that determine the final properties of the membrane. The membranes produced in this way are tested in the FO system, aimed at determining the speed of water transport and the reverse diffusion of ions. Osmotic stands with different salt concentrations (draw solution) and deionized water (feed solution) are used, or tests in FO systems that reflect the membrane work conditions more, where dextran draw solution and NaCl feed solution are used ,16,17,18portance .4), ascorbic acid, hydroiodic acid, or hot strong alkaline solutions can be listed [Graphene oxide contains graphite structure sheets decorated with oxygen-containing groups with a thickness of one or a few layers of carbon atoms. GO may be reduced via thermal reduction, chemical reduction, or multi-step reduction with the use of more than one method. As effective chemical reducers hydrazine, metal hydrates . Unlike other concepts, naturally occurring sub-nanometric defects in graphene were the active filter paths of the membrane and the key to the solution. The novelty is the use of reduced graphene oxide which allowed for sealing larger defects resulting from graphene growth and transfer steps. The analysis of graphene after its growth stage, as well as during transfer and after transfer to the polymer substrates , was performed. Several reagents reducing graphene oxide were used and their influence on the morphology of the defect-sealing material was determined. Filtration tests were carried out in the FO system with the use of NaCl salt solution aiming to determine the dependence of semi-permeable properties on the graphene oxide reducing agent used.The aim of this work was to manufacture and investigate semi-permeable FO membranes based on HSMG®) according to the procedure described in detail in the patent  and the article [Monolayer polycrystalline graphene for composite membranes preparation was synthesized via the metallurgical method . It was used to prepare composite graphene membranes in each test. Membrane thickness equaled 110 µm and was declared by the manufacturer as having water permeability of ≥10 mL min−1 cm−2 bar−1 at a temperature of 25 °C. We transferred graphene on a polysulfone membrane side with minor porosity where pore diameter was from 0.1 to 1.0 μm. The density of the pores was 1.05 × 106 mm−2.Porous polysulfone membranes were used as graphene supporting substrates (MicroPES−3 (9.2 g of PMMA-100 mL of chlorobenzene), was used for covering graphene during the transfer procedure.Poly(methyl methacrylate) (PMMA) with a molecular weight of 996,000 g/mol of the Aldrich Chemistry Company, Burlington, MA, United States, dissolved in chlorobenzene , with a concentration of 0.10 mol dmThe solvent used to dissolve and remove the PMMA foil from graphene during the transfer procedure was 2-propanol with a technical grade of 70% .Graphene oxide with 0.4% dispersion in water (4 mg/mL) was purchased from the Advanced Graphene Products Company, Nowy Kisielin, Poland.4) A.C.S , L(+)-ascorbic acid (C6H8O6) A.C.S , and green tea leaves commercially available in the local market, were used.For the reduction of graphene oxide, diluted commercial 80% hydrazine hydrate , pure ethylenediamine A.C.S , 98.5 % sodium borohydride  pure p.a. from Chempur, Poland, was used. For membrane assembly in the grip of side-by-side diffusion cell Polydimethylsiloxane (PDMS), SYLGARD™ 184 Silicone Elastomer , was used.® graphene transfer process onto a polysulfone membrane was conducted using the electrochemical delamination method [2. This was followed by drop/blade coating graphene with PMMA in chlorobenzene as a temporary carrier layer. The polymer was dried at a temperature of c.a. 40 °C for 30 min. Delamination of the HSMG® graphene was carried out using a laboratory half-automatic station in 0.5 mol/L NaOH solution at a constant voltage of 4.5 V at a sample submersion angle of 35° and a submersion linear speed of 0.02 mm s−1. Then, graphene on PMMA foil was washed three times in deionized water. Graphene on polymer foil was placed on a wetted polysulfone membrane and roll pressed with a sponge roller and then annealed at 70 °C for 5 min. A gentle pressing was used to get rid of water and provide good attachment while avoiding damaging the graphene. Then it was placed in a chamber with boiling isopropanol to remove the PMMA-supporting layer. The graphene membrane was then washed twice in cold isopropanol to remove any polymer residues and air-dried.The HSMGn method . The proAfter transfer on the target, substrate graphene was subjected to SEM analysis (HITACHI S 3000 N). In this way, we established that no new cracks and tears are introduced to graphene at any stage of the transfer method.® graphene. It was prepared by the chemical reagent reduction of graphene oxide. rGO reduced with hydrazine without centrifugation of the reaction products was prepared via preparation of 1% solution of hydrazine in 50 mL of 0.4% GO in DI water suspension and left for 48 h to reduce at room temperature (RT).Reduced graphene oxide (rGO), listed in The reduction of GO via hydrazine and ethylenediamine was conducted via preparation of 1% solution of hydrazine and ethylenediamine in 50 mL of 0.4% GO in DI water suspension, respectively. The solution was kept for 48 h at RT. Next, the rGO was centrifuged . After being centrifuged, the washing procedure was applied. The reaction mixture was poured out and 50 mL of DI water was added. In the next step, rGO sediment was extensively vortexed and mixed using an ultrasonic cleaner for 15 min. The washing procedure was repeated six times .4 (0.4 g), as a reducing agent, was added to 50 mL of 0.4% GO in DI water suspension. To obtain rGO, the suspension-prepared mixture was kept with continuous stirring at room temperature for 12 h. Next, the suspension was washed according to the procedure described above [NaBHed above .In the next stage of the experiment process, the reduction was carried out using ascorbic acid (0.4 g) diluted in 50 mL of 0.4% GO deionised water suspension. The reaction mixture was kept for 48 h at RT with gentle stirring. After the reduction process, the rGO suspension was washed according to the procedure mentioned above .The last reducing agent used to reduce graphene oxide was green tea leaf extract. 15 g of dried tea leaves were boiled with 200 mL of DI water at 80 °C for 1h in a 250 mL flask to obtain the tea leaf extract. Next, the prepared solution was filtered. The 50 mL GO solution and 50 mL tea leaf extract were heated to 90 °C and then mixed in a ratio of 1:1 (vol. ratio). The reduction of GO was carried out with continuous stirring at 90 °C for 12 h. After this time, the above-mentioned washing procedure was applied .Raman spectroscopy measurements were performed using an inVia Renishaw Raman spectroscope equipped with a 532 nm laser. The laser power during the measurements was reduced to the value of 0.3 mW to avoid sample damage, while laser exposition time was 10 s. A 50× objective was used for all measurements.2 greater than 0.98.For the needs of spectral analysis, each peak was fitted to a single Lorentzian using the PeakFit software. The fits achieved an R−1 was measured by Fourier transform infrared spectroscopy . Spectra were recorded at a resolution of 2 cm−1 using a highly sensitive MCT-B detector (Telluride Mercury Cadmium Telluride). Measurements were made in the reflection mode with the use of the Sequelle DRIFT reflection adapter, for the incidence of the radiation beam equal to 20 degrees. Spectra were collected from 256 scans.The infrared absorption of GO and rGO samples in the spectral range from 4000 to 500 cmThe X-ray diffraction studies of graphene oxides were performed with the use of the PANALYTICAL Empyrean X-ray diffractometer . The diffraction patterns were collected using a tube with a Cr anode-emitting characteristic radiation with a wavelength of λ = 2.291 Å, operating at a voltage of 30 kV and current of 55 mA. Due to the high roughness of the graphene oxide samples deposited on nickel substrates, on the primary radiation beam, an X-ray lens with a cross collimator was used. On the reflected beam path, a 0.18 deg parallel beam collimator, 0.04 rad Soller slits, and a proportional detector were installed. The tests were carried out in the angular range from 2θ = 10–60°, with a 0.05° step, and time per step equal to 5 s.® in the amount of 30 µL per 1 cm2. After 5 min, the excess solution was washed off with a gentle stream of water. In the next step, another 10 µL/cm2 of rGO/water solution was applied on the graphene membrane and air-dried. Each time before use, the rGO solution was dispersed by means of ultrasound. Due to the hydrophobic nature of graphene, a water suspension of rGO tended to accumulate in graphene discontinuities (uncoated polysulfone area). In this way, graphene HSMG® defects were sealed. The preparation of each membrane was performed in the same way as presented in The as-prepared rGO suspensions and unreduced GO suspension were dispersed in distilled water at a concentration of 0.1%, respectively. Then the solution was applied onto a polysulfone membrane covered with graphene HSMG® graphene to the PS substrate and after sealing with reduced graphene oxide. The observation of the surface of the graphene membranes was performed using the HITACHI S 3000 N scanning electron microscope. The samples were placed in the chamber using a table pressed with a ring in such a way as to ensure good charge-discharge from the entire surface of the graphene composite area. The tests were performed at the intensity HV = 5 kV, in SE and AEE modes, which enabled the identification of defects and impurities in the structure. The contrast in AEE mode is the result of the differences in the electrical conductivity of the tested micro-areas.Once made, the graphene membranes were subjected to qualitative investigations. The tests were carried out after the transfer of HSMGIon separation effectiveness and water flow through membranes driven by osmotic pressure gradient were measured with a side-by-side diffusion cell with a 22 mm orifice. The volume of each chamber  was 64 mL .One of the cylinders was filled with 0.2 M NaCl as a draw solution and the second was filled with degassed, deionized, UV lamp-treated water as a feed solution.The membranes were sealed in a grip with a semi-liquid polydimethylsiloxane polymer which was then polymerized. This provided membrane stabilization and good sealing while causing no damage to the working part of a membrane.® graphene to the PS substrate and after sealing with reduced graphene oxide.After being made, the graphene membranes were subjected to qualitative investigations. The tests were carried out after the transfer of HSMGEach time after membrane assembly both cylinders with feed and draw solution were filled simultaneously to avoid membrane deflection. The tests were conducted at room temperature (20 °C) for 24 h. Each time the salt concentration was measured on each side of the membrane after the test. To evaluate water flux (J), the transport of water from the feed side to the draw side, driven by the osmotic gradient that resulted in a rise of water level in the draw side, was measured using a graduated glass tube during the test.Each experiment was repeated twice by replacing the solution in each cylinder.c is the molar concentration of the solute, R is the gas constant, and T is the temperature in Kelvin. The calculated pressure was 9.7 bar.The osmotic pressure was calculated based on the van’t Hoff equation (−2 h−1 bar−1) was calculated based on the equation V is the change of water volume in a container (mL), A is the membrane-active surface area (m2), t is time (h), and p is theoretical osmotic pressure owing to the concentration difference (bar). The ion’s flux (mol m−2 s−1) was calculated by dividing the change of salt concentration in the container with feed solution by the test time and the membrane surface. The degree of ion transport blocking efficiency was calculated relative to an uncoated polysulfone membrane (bare PSU), assuming 0% ion blocking efficiency is the same ion transport as bare PSU and 100% ion blocking is no ion transport.The water flux through the membrane (J)  may be considered as a function of the C/O ratio:In accordance with the work , differeinf-G app < 0; C/O < 10GO = D’ inf-G app < 25; 10 < C/O < 500rGO = 0 < D’ inf-G app > 25; C/O > 500Graphene = D’ app) is equal to −0.52, at the same time fulfilling the condition D’ inf-G app < 0, which is typical for GO.In view of the above, in the case of sample No. 1  the value of the difference .The difference in the D’ and Ginf-G app) amounting in both cases, ~13 . The value placed in this range is characteristic of the reduced graphene (rGO). The higher D’ and Gapp difference, the more reduced the GO. Therefore, based on the obtained results it can be stated that the most effective reduction has been achieved by the reaction of GO with hydrazine, which is also confirmed by the FTIR and XRD analysis.According to the Raman spectroscopy analysis, samples No. 2 and 3 (the hydrazine-reduced GO’s) show the highest value of  and 4 (GO reduced with L(+)-ascorbic acid). The difference between D’-Gapp) value was equal to 1.79 and 0.5, respectively, which means that both ethylenediamine and green tea turned out to be the least efficient reducing agents for graphene oxide in these experiments. However, in the case of the reactions with green tea the lowest level of the reduction of GO was obtained, which is also confirmed by the XRD and FTIR analysis.In Raman measurements, the least effective reduction of GO was obtained for samples No. 6 and 7, where  identified by the adsorption bands at 1240 cm−1 and 1075 cm−1 derived from the stretching vibrations of the C-O bonds. In addition, at 1627 cm−1, there is a typical maximum for stretching vibrations of C=C bonds taking place in the hexagonal ring of graphene oxide [−1, a wide band also appears, originating from both symmetric and asymmetric stretching vibrations of C-H bonds in aliphatic hydrocarbon chains attached to the GO ring structure [The spectrum of unmodified GO shown in ne oxide ,29,30. I−1  and at 1280 cm−1, which correspond to the stretching vibrations of C-N bonds, emerge [−1, corresponding to the stretching vibration of N-H bonds and characteristic for the NH2 group, appear. Additionally, in the spectrum of graphene reduced with non-centrifuged hydrazine, a maximum at 1530 cm−1, corresponding to the C-NH2 stretching vibrations, emerges along with a wide and distinct band in the range from 3500–3300 cm−1 related to the stretching vibrations of N-H bonds. This means that hydrazine centrifugation is necessary to clean the surface of the reduced GO to get rid of the toxic residues of the reducer used. Nitrogen-containing compounds allow not only for the reduction of GO but also the formation of bridges between carbon atoms in different rGO flakes [When it comes to GO reduction, hydrazine, sodium borohydride, and ascorbic acid turn out to be the best reducing agents and this can be observed in the IR absorption spectra. First of all, following reduction the band originating from the C=C vibrations shifts away from the position dedicated to GO. In hydrazine reduced material, the bands originating from hydroxyl and carboxyl groups disappear, while groups typical for C=N connections in the range of 1690–1640 cm, emerge ,31. In aO flakes ,22. On tO flakes .4. After reduction with this substance, no maxima assigned to -OH and -COOH groups are observed but, instead, an intense band at 1270 cm−1 originating from epoxy groups is present. In addition, a new peak emerges at 1592 cm−1, related to the presence of COO- anions, which is a consequence of the presence of the sodium cation in the reducer used and the formation of the carboxylic anion [Another effective reducing agent is NaBHic anion .2H8N2, the C=C peak is still at the constant 1627 cm−1 position. In the spectrum of GO reduced with green tea, apart from signals corresponding to carboxyl groups, epoxy, and other C-O connections characteristic for GO, absorption bands typical for this reducing agent, appear. Moreover, the presence of a maximum at 1655 cm−1 assigned to the stretching vibrations of the C=O bond in first-order amides, as well as that at 1327 cm−1, due to the stretching vibrations of aromatic amines of I and II order [−1 and 1056 cm−1 are concerned, they originate from stretching and deformation vibrations, respectively, of C-O bonds in the C-OH group of polysaccharides [2 amine groups are recorded in the spectral range from 3300–3150 cm−1 (stretching vibrations) and at 1580 cm−1 (deformation vibrations of N-H bonds in the -NH2 groups), and those originating from C-N bond stretching vibrations are observed at 1220 cm−1 [2- and -CH3 groups is also higher in ethylenediamine-reduced GO.Only in the cases of GO treated with GT and CII order ,31, is rcharides . FinallyThe reflection mode geometry X-ray diffraction pattern for a neat GO has a strong (001) diffraction peak indicating the preferred orientation of graphene oxide basal planes parallel to the sample plane. The two-theta position of the (001) GO diffraction peak can show a range from ~7–12 2theta (Cu Kα radiation) that corresponds to ~10–18 2theta for Cr Kα radiation, depending on the amount of residual water intercalated between basal planes in a GO film . InterplAn average number of layers per flake of GO and r-GO is calculated using the flake size and d-spacing parameters obtained from XRD analysis.n is the number of layers, D is the crystallite size, and d(001) is the interplanar distance.Here, The results of the explained estimations above for all samples are summarized in In sample No. 2 intense reduction of GO can be observed, but calculations of d, D, and n values also indicate a very intense conglomeration of remaining GO flakes and likely the exchange of pre-existing H-O bonds between flakes with reducing agent species. This effect is likely also related to the lack of centrifugation, the product of the hydrazine reduction reaction, and the formation of C-N, C=N bonds.In the case of sample No. 4, reducing agents caused the removal of H-O species from between GO flakes and the partial transformation into rGO, which is indicated by decreasing the d for GO and the appearance of the rGO peak.For sample No. 5, the reducing agent, however, caused a partial reduction of GO to rGO, but at the same time, the increment in d’s is observed and in crystallite dimensions.For sample No. 6, there is a shift towards lower 2Th values only. No rGO peak was observed which can indicate the applied reducing agent species added to existing H-O ones. In sample No. 7, the decrease of d interplanar spacing of GO is observed, however, no rGO peak appeared. The calculation of the “n” value suggests that the applied agent only caused the division of GO flakes without any reducing effect.In the examined group of samples, only sample No. 3 shows the complete reduction of GO without any additional effects.In all cases created, rGO is characterised by very close d, D, and n values.The membranes were manufactured and labeled as described in ® polycrystalline graphene at the stage of synthesis and/or transfer to a polysulfone substrate. On membrane 1, defects in the graphene layer were masked with graphene oxide. Large GO conglomerates covering the surface of HSMG® graphene are visible here. Membranes 2 and 3 were sealed with reduced graphene oxide as a result of the use of hydrazine. There is an even coverage of the rGO graphene surface, with no major conglomerates. As the AEE images show, there are no non-conductive sites, which proves a very good continuity of graphene layers supplemented with rGO. On membranes 4, 6, and 7 the coating is not as uniform as in the other cases (except membrane 1), some of the sealing material tended to accumulate in larger aggregates on the surface of the membrane, thereby forming large conglomerates GO/rGO. The surface of diaphragm No. 5 is also characterised by homogeneous coverage GO/rGO as for diaphragms 2 and 3. The wrinkles characteristic of graphene oxide/reduced graphene oxide can be seen here. The entire surface of HSMG® graphene is covered with such a wrinkled coating. Furthermore, all images of membranes with transferred graphene show reflections of the boundaries of copper grains from the growth substrate, however, this does not affect the continuity of graphene in these areas.In the presented results of osmotic tests for the as-prepared composite graphene membranes, the effectiveness of blocking the ion transport ranges from 30–95%. For the membrane with unsealed graphene (No. 8), no semi-permeable properties were noted, it was characterized by high ion transport and no water flux caused by osmotic pressure .−1 m−2 bar −1 and an ion blocking efficiency of approximately 60%.A reference to other options for the composite membrane preparation is also the membrane sealed with non-reduced graphene oxide. A water flux achieved for it is over 8 mL hThe reduction of GO with hydrazine (sample No. 2) and its use as a material for sealing defects in graphene increased the ion blocking efficiency for the membrane prepared in this way up to 87%, however, a water flow close to zero was noted.For membrane 3, in which a completely hydrazine-reduced graphene oxide was used as the sealing material, the same ion blocking efficiency as in membrane 2 was achieved, but with a significantly higher water flow. Here, in relation to membrane 1, ion blocking was higher at lower water flow rates. This phenomenon is associated with a reduced interplanar distance in the rGO flakes, a lower number of oxygen groups in reduced graphene oxide flakes, and, thus, the more accurate sealing of defects. In this case, the blocking of the ion flow and water molecules is also greatly influenced by the uniform coverage of the membrane surface by rGO and the low tendency to form conglomerates. On the other hand, the increase in water flow in membrane 3 with respect to membrane 2 with the same degree of ion blocking may be due to the greater presence of C=N and C-N bonds in membrane 3. The blocking of water flow through membrane 2 may also be influenced by non-centrifuged reduction reaction products.® also contributes to this high water flow. However, the resulting large rGO conglomerates, and the tendency to form clusters on the surface, do not sufficiently cover the defects in HSMG® graphene. Therefore, the migration of ions through this type of membrane is high and the repeatability of the results is worse.The most intense water flow was achieved for the membrane with vitamin C-reduced graphene oxide. In this case, the effective removal of OH and COOH groups, the reduction of the distance between the planes of non-reduced graphene oxide, and the small distances between the planes of reduced graphene oxide translated into such a sealing of large defects in graphene that the highest water transport was obtained under the influence of osmotic pressure. The ability to selectively coat the surface of graphene HSMG−1 m−2 bar−1 with an ion blocking efficiency of 70%. This is due to the very low degree of reduction of GO and the presence of nitrogen bonds, which further increased the interplanar distances, which was demonstrated in FTIR and XRD results. In this case also, conglomerate formation and GO aggregation on the HSMG® graphene surface did not sufficiently cover the defects, but selective coverage resulted in high water flow.Sealing graphene with ethylenediamine-reduced GO resulted in a water flow of 11.5 mL hGreen tea turned out to be an ineffective reagent, which not only had almost no effect on the reduction of graphene oxide but also the transport of water and ions was close to the one obtained for bare graphene. The low level of ion blocking, in this case, was also related to the formation of conglomerates and aggregation of GO on the surface of the graphene membrane. The low ability to cover defects in the graphene layer resulted in a very low water flow due to there being practically no osmotic pressure.All prepared membranes showed the stability of operation in more than one osmotic test, moreover, most often the second measurement resulted in a higher water flow and slightly higher ion transport than during the first measurement. It may be related to the intercalation of water molecules between the flakes of reduced graphene oxide and between graphene and the sealing rGO on the border of graphene defects.−2 h−1 . Only the solution based on green tea did not give positive results. Here, it is most likely that the low degree of sealing affected the generation of low osmotic pressure, which translates into low water flow. The optimal solution, from the point of view of the flow rate, and the degree of ion blocking, is the solution using GO reduced with ethylenediamine, with a water flow of 12 mL m−2 h−1 bar−1 and ion blocking at the level of 70%.The study showed that the graphene membranes created are semi-permeable to aqueous solutions. The effectiveness of blocking NaCl ions and the rate of water flow through the membrane are dependent on the degree of GO reduction used to cover HSMG


One of the urgent problems of materials science is the search for the optimal combination of graphene modifications and carbon nanotubes (CNTs) for the formation of layered hybrid material with specified physical properties. High electrical conductivity and stability are one of the main optimality criteria for a graphene/CNT hybrid structure. This paper presents results of a theoretical and computational study of the peculiarities of the atomic structure and the regularities of current flow in hybrid films based on single-walled carbon nanotubes (SWCNTs) with a diameter of 1.2 nm and bilayer zigzag graphene nanoribbons, where the layers are shifted relative to the other. It is found that the maximum stresses on atoms of hybrid film do not exceed ~0.46 GPa for all considered topological models. It is shown that the electrical conductivity anisotropy takes place in graphene/SWCNT hybrid films at a graphene nanoribbon width of 4 hexagons. In the direction along the extended edge of the graphene nanoribbon, the electrical resistance of graphene/SWCNT hybrid film reaches ~125 kOhm; in the direction along the nanotube axis, the electrical resistance is about 16 kOhm. The prospects for the use of graphene/SWCNT hybrid films in electronics are predicted based on the obtained results. In the last decade, the possibility of combining graphene and CNTs has attracted much attention from the research community in order to obtain new multifunctional hybrid materials with promising properties due to the synergistic effect caused by the interaction of nanostructures of various dimensions—1D nanotubes and 2D graphene ,7,8,9,102/Si substrate has been presented by Liu et al. [5), fast response time (~100 μs), and ultra-wideband sensitivity in the range of electromagnetic radiation from visible to near-infrared. Liu et al. have also developed the flexible photodetector utilizing van der Waals bonded graphene-SWNT hybrid films as the light-harvesting layer. This device on a flexible polyethylene terephthalate substrate demonstrated a high photoresponsivity of ~51 A/W and a fast response time of ~40 ms over the visible wavelength range [2 molecules. It was found that the H2 response in SWCNT/graphene nanohybrid improved by 50% as graphene provides more efficient charge transfer [−1, outstanding power capability of ~390 mA∙g−1, and cyclability over 1000 operating cycles with maximum Coulombic efficiency [−1 in an ionic liquid at room temperature. In addition, an increase in the specific capacity of electrodes by 29% after 1000 operating cycles were recorded, which indicates their excellent cyclicity [Graphene/SWCNT hybrid structures with horizontally oriented nanotubes find their application as a material for creating the element base of various nanodevices. In particular, highly sensitive photodetectors have been developed on the basis of atomically thin graphene/SWCNT hybrid films. A photodetector based on van der Waals graphene/SWCNT heterostructures located on a SiOu et al. . The proth range . An all-th range . A hybritransfer . Layeredficiency . Composiyclicity .Along with the development of various devices based on graphene/SWCNT hybrid structures, fundamental studies of the regularities of physical processes in these structures are also being carried out. The mechanisms of thermal and electrical conductivity in graphene/SWCNT hybrid structures are studied using computer simulation methods. Using the method of nonequilibrium molecular dynamics, it was found that the thermal boundary conductivity in hybrid structures based on horizontally oriented SWCNTs and graphene nanoribbons increases linearly with increasing temperature due to the significant role of inelastic phonon scattering. It was shown that as the strength of the interphase interaction increases, the thermal boundary conductivity monotonically increases due to the emerging enhanced phonon coupling between SWCNTs and graphene . Based oThe aim of this paper is to study the peculiarities of the atomic structure and the regularities of current flow in hybrid films formed by bilayer zigzag graphene nanoribbons and a SWCNT  layer using theoretical and computational methods. The choice of SWCNTs  and zigzag graphene nanoribbons is due to the following reasons. Chiral SWCNTs  with a diameter of 1.2 nm are among the most frequently synthesized single-walled nanotubes ,33,34. IThe atomic structure of graphene/SWCNT hybrid films was calculated using the self-consistent charge density-functional tight-binding (SCC-DFTB) method . This meIn order to quantitatively evaluate the stability of graphene/SWCNT hybrid films to internal deformations, the distribution of local stresses of the atomic network was calculated. The stress on each atom was calculated as the ratio of the force acting on the atom to the surface area of the atom, taking into account its immediate environment. The force was defined as the derivative of the energy of the atom with respect to its coordinates x, y, z. The energy of each atom was calculated by the SCC-DFTB method in the DFTB+ software package version 20.2 ,43.T(E) and static electrical conductivity G. The function T(E) is determined by the expression:FE is the Fermi energy of the material of the contacts, TF is the thermal broadening function; e is the electron charge, h is the Planck’s constant, e2/h is the quantum of conduction .The electrical conductivity was calculated within Landauer–Buttiker formalism . This foT(E) were carried out for supercells of graphene/SWCNT hybrid films consisting of 250–300 atoms. In view of the large dimension of the considered electronic system, the original method for the accelerated calculation of the transmission function T(E) was applied using the original Mizar program [T(E) for a small number of k-points of the first Brillouin zone and then interpolating it for any k-point of the first Brillouin zone and recovering the full transmission function T(E).In this study, the calculations of the transmission function  program . This meTo analyze the electronic distribution in the studied graphene/SWCNT hybrid films, the Mulliken Population Analysis (MPA) was carried out . AccordixL = 1.72 nm and yL = 1.12 nm, respectively.To construct atomistic models of graphene/SWCNT hybrid films, we used SWCNTs  with a diameter of 1.2 nm and bilayer zigzag graphene nanoribbons. One of the graphene layers was shifted relative to the other in the direction of the Y-axis . Wherein bilayer graphene was located above the SWCNT surface at a distance of 0.34 nm. In total, three topological models of the graphene/SWCNT hybrid films were considered. These models differed in the width of the graphene nanoribbon in each layer. With an increase in the width of the nanoribbon, the displacement of the graphene layers relative to each other in the direction of the Y-axis  changed. In the first version (model V1) of the initial graphene/SWCNT film, the width of the graphene nanoribbon was 2 hexagons (~0.5 nm), the displacement of the layers along the Y-axis was 0.48 nm. In the second version (model V2), the width of the graphene nanoribbon was 3 hexagons (0.71 nm), the displacement of the layers was 0.27 nm. In the third version (model V3), the width of the graphene nanoribbon was 4 hexagons (0.92 nm), the displacement of the layers was 0.06 nm. The distance between graphene layers along the Z-axis (perpendicular to the nanotube axis) was 0.34 nm for all considered topological models of graphene/SWCNT hybrid films. xL, yL with the optimization of the atomic network geometry of the supercell constructed for these xL, yL. The lengths of the translation vectors of the supercells after optimization are shown in xr and yr, respectively). xr/yr) of nanotubes in graphene/SWCNT hybrid structure. According to these data, the degree of deformation was 1.2 for all three topological models. The atomic structure of the initial graphene nanoribbons was also deformed as a result of the interaction of nanoribbons with each other and with the nanotube. Moreover, depending on the width of the graphene nanoribbon, different orientations of the graphene layers with respect to the nanotube were observed. As can be seen from The initial atomic structures of the supercells were optimized to find their equilibrium configuration, i.e., configurations characterized by the minimum energy. The atomic structure of the supercells was optimized by the SCC-DFTB method. In the course of optimization, a relaxation scanning of the energy surface of the hybrid film was carried out. This scanning implied a step-by-step change in the lengths of the translation vectors As noted in fH, which was determined by the following formula:filmE is the energy of the hybrid film, grE is the energy of graphene layers, tubeE is the nanotube  energy, N is the number of atoms in the supercell. The structure of the hybrid film was configured in such a way that its total energy in absolute value was less than for its individual components. The ΔfH values are given in Another confirmation of the energy stability of the constructed supercells was the result of calculating the formation enthalpy ΔFE. The values of FE for each topological model of the hybrid film are given in gapE opens (see The next stage of the study was to identify the features of the electronic structure of the studied graphene/SWCNT hybrid films. The distributions of the density of electronic states (DOS) were calculated for each of the constructed supercells. Our task was to determine how the DOS profile of graphene/SWCNT hybrid films was formed by evaluating the contribution of individual graphene nanoribbons and nanotube . pens see  as in the versus 0.157e for model V1), which led to an increase in the intensity of the DOS peak at the Fermi level for individual graphene nanoribbons in this case , which characterized the probability of the passage of electrons through the given structure. The resulting plots of the function T(E) are shown in T(E) profile near the Fermi level determines the value of electrical conductivity G. The T(E) plots for the direction of current transfer along the Y axis are marked in green, and along the X axis in red. The values of the T(E) in the plots are given in quanta of conductance e2/h. To explain the obtained dependencies, the T(E) plots of its constituent graphene and nanotube (in a square frame) are presented for each topological model of graphene/SWCNT hybrid film. The presented plots demonstrate that either graphene (current transfer in the direction of the X-axis) or a nanotube  (current transfer in the direction of the Y-axis) makes a decisive contribution to the formation of the T(E) profile. The T(E) profile contours of graphene/SWCNT hybrid film near the Fermi level largely repeat the DOS profile contours in this energy range. This allows us to use the conclusions about the influence of the electron charge density redistribution between the atoms of the nanotube and graphene layers, made in the analysis of the DOS, to explain the differences between the T(E) profiles of the models V1 and V2 and the T(E) profile of the model V3. In order to quantify the ability of graphene/SWCNT hybrid films to conduct current, we calculated the electrical resistances in the directions of current transfer along the X and Y axes . The resistance was calculated as the reciprocal of the electrical conductivity G, which was determined by Formula (2). The calculated resistance values are presented in yR was less than xR. This can be explained by the fact that the value of T(E) in the direction of the Y-axis is equal to “2” over a large energy interval, but in the direction of the X-axis, the T(E) reaches the value “3” at the Fermi level and then decreases to unity in almost the entire considered energy range. On the contrary, in the case of the topological model V3, the resistance values in different directions of current transfer differ by a factor of tens, i.e., the phenomenon of electrical conductivity anisotropy takes place. In the direction of the X-axis, the resistance reaches ~ 125 kΩ. This is explained by the fact that the function T(E) takes values less than unity over the entire energy range near the Fermi level. In the direction of the Y-axis, the resistance was about 16 kΩ, which was three times higher than the resistance values for models V1 and V2 since the T(E) at the Fermi level takes almost zero value in this case  profiles for the topological models V1, V2, and V3, we calculated the maps of the transmission function T, on which the wave number k was plotted. This wave number corresponds to the direction in which the partition of the reciprocal space was carried out. The calculated maps T are shown in For a visual interpretation of the yk), the function T(E) for the models V1 and V2 takes maximum values (of the order of 3), either at the Fermi level (model V1) or in the immediate vicinity of it (model V2). This result was in good agreement with the features of the profiles of the function T(E) in the vicinity of the Fermi level shown in xk), the function T(E) takes on the value “2” at almost all points of reciprocal space with the exception of individual “islands” explaining small deviations of the function T(E) from the value “2” near the Fermi level observed in T(E) in the direction of the X-axis for the model V3 was zero throughout the reciprocal space, except for a small number of edge points located far from the Fermi level. As can be seen from T(E) at the Fermi level and in its vicinity was close to zero and gradually increased with distance from it. In the direction of the Y-axis, the map T was more rarefied since the function T(E) has a large number of conduction channels in this direction of current transfer. This explains the anisotropy of the conducting properties observed for this topological model of graphene/SWCNT hybrid film.These maps clearly show that in the case of the current transfer in the direction of the X-axis (partition by In this work, the theoretical and computational study of layered films formed by bilayer graphene and a layer of chiral SWCNTs was carried out. The results of this study made it possible to determine new topological models of graphene/SWCNT hybrid structures, characterized by high energy stability, and to reveal the regularities of the topological control of their electrically conductive properties. For the first time, at the level of computer simulation, we considered the atomic configurations of graphene/SWCNT hybrid films, in which the mutual arrangement of the graphene layers and the SWCNT layer led to the formation of structural regions with increased density, which corresponds to the data of modern experiments on the synthesis of graphene/CNT films . Based o


In the 2016 experiment by Crossno et al. the electronic contribution to the thermal conductivity of graphene was found to violate the well-known Wiedemann–Franz (WF) law for metals. At liquid nitrogen temperatures, the thermal to electrical conductivity ratio of charge-neutral samples was more than 10 times higher than predicted by the WF law, which was attributed to interactions between particles leading to collective behavior described by hydrodynamics. Here, we show, by adapting the handbook derivation of the WF law to the case of massless Dirac fermions, that significantly enhanced thermal conductivity should appear also in few- or even sub-kelvin temperatures, where the role of interactions can be neglected. The comparison with numerical results obtained within the Landauer–Büttiker formalism for rectangular and disk-shaped (Corbino) devices in ballistic graphene is also provided. Soon after the advent of graphene, it became clear that this two-dimensional form of carbon shows exceptional thermal conductivity, reaching the room temperature value of 00 W/m/K , being o00 W/m/K . Althoug00 W/m/K ,4 allowity point . One canty point , but dirThe Wiedemann–Franz (WF) law states that the ratio of perature (1)κelσ=For metals, Equation  with L≈LL≈L0  holds true of L0  with a fIn graphene, the situation is far more complex, partly because o et al.  show thaHigh values of the Lorentz number  can be understood within a hydrodynamic transport theory for graphene ,15,16, wIn this paper, we show how to adapt the handbook derivation of the WF law  in ordertangular ,20,21 antangular ,23 samplThe remainder of the paper is organized as follows. In C) derived within kinetic theory of gases [v is a typical particle velocity, and ℓ is the mean-free path (travelled between collisions with boundaries or other particles). C in Equation , as follows from Equation  vanishes in the Equation  and the Equation  for d=2, for d=3 , but the for d=3 ,27 even  for d=3 .C in Equation =d2nEquation , we obtaNow, taking Equation , obtainiIt is now sufficient to divide Equations  and 17)17) side-d. More careful analysis also shows that the parabolic dispersion of Equation  value of σ0  may therTo understand the above conjecture, we refer to the approximate dispersion relation for charge carriers in graphene, showing up so-called Dirac cones,The value of the Fermi velocity Charge carriers in graphene are characterized by an additional (next to spin) quantum number, the so-called valley index. This leads to an additional twofold degeneracy of energy levels, which needs to taken into account when calculating the density of states,Subsequently, the carrier concentration at F index for symbols denoting the Fermi energy and the Fermi wavevector to emphasize that they can be tuned (together with the concentration) by electrostatic gates, while the Fermi velocity In the above, we intentionally omit the ocity vF  is a matDespite the unusual dispersion relation, given by Equation , the relEquation  leads tomC=ℏ22π∂AEquation  for freen  , replaciC  corresponds to y μ>0 is gigiven byL=κσ0T=FL=κeiven by3Ln=gsgvh∫Before calculating For instance, the linear transmission-energy dependence =9ζ gap may enhance the Lorentz number. Instead of Equation , we putFor Equation  can be aThis time, the result given in Equation  can be sm.An apparent feature of Equation  is that nductors . SimilarEquation  for Δ≫kBA different behavior appears near the band boundary, i.e., for grals Ln  matters.Closed-form expressions for Asymptotic forms of Substituting the above into Equation , we obtam  and evanescent waves Tons, see ),53)knknW and lj is the half-odd integer angular momentum quantum number, with a corresponding transmission probabilityk is same as in Equation T(ε)Equation , and≈g0ΩXThe exact transmission-energy functions Equation  for the T) from the Wiedemann–Franz regime, with a flat Close to the charge-neutrality point, i.e., for Equation   or to the bottom of the conduction band (the unipolar case), proves that the bipolar band structure is also important  as expected for a model transmission energy dependence, L the sample length.Finally, the Lorentz numbers, for different dopings and temperatures, are elaborated numerically from exact solutions available for the rectangular sample and the Corbino (edge-free) disk in graphene, both connected to heavily-doped graphene leads. The results show that Our results complement earlier theoretical study on the topic  by inclu


Thanks to the unique properties of graphite oxides and graphene oxide (GO), this material has become one of the most promising materials that are widely studied. Graphene oxide is not only a precursor for the synthesis of thermally or chemically reduced graphene: researchers revealed a huge amount of unique optical, electronic, and chemical properties of graphene oxide for many different applications. In this review, we focus on the structure and characterization of GO, graphene derivatives prepared from GO and GO applications. We describe GO utilization in environmental applications, medical and biological applications, freestanding membranes, and various composite systems. The fun1F1]n show small flakes of fluorographene which consist of multiple wrinkled sheets. Whereas micrographs of CRG do not show such wrinkled structure of multiple sheets, the last micrographs of TRG show small flakes of multiple-sheet structure which are highly wrinkled. According to EDS 1]n. The synthesis of such material consists of two consecutive oxidation steps of graphite. After the first oxidation by the Tour method, GO is obtained and further used as a starting material for the second oxidation. The second oxidation runs according to the Tour method as well n [Fluorographene is fluorinated graphene with stoichiometry [C1F1]n ,87. As w1F1]n . The pre1F1]n . For the1F1]n . Isoprop1F1]n , ethanol1F1]n , acetoni1F1]n , and chl1F1]n  can be m1F1]n . The pro1F1]n .In order to provide typical analytical results of GO, a sample of GO was prepared by modified Tour’s method  and analTransmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), and scanning electron microscopy (SEM) were used to study the surface of GO. The first micrographs in The composition of the sample can be determined via X-ray fluorescence (XRF). The composition of GO depends on the level of oxidation of the sample. Generally, graphene oxide is composed of carbon, oxygen, and hydrogen, but there are very often other impurities from the starting materials, such as sulfur, chlorine, nitrogen, manganese, and potassium . ManganeThe composition of TO-GO can be also investigated by elemental analysis (EA) . The res−1 and 1600 cm−1, respectively, are usually registered. The first local maximum is called the D band and shows a quasitetrahedral coordination with sp3 carbon hybridization . The other local maximum is called the G band and detects a planar arrangement with sp2 hybridization (regular graphene lattice). The D/G ratio, calculated from the intensity of peaks, shows the level of oxidation of the sample and should be around 1.00 [Raman spectroscopy is a powerful tool for the determination of defect rate. Using Raman spectroscopy, two local maxima around 1350 cmund 1.00 .X-ray diffraction is used to determine the interlayer distance between GO layers. Whereas pure graphite has (002) reflection at 26.3° that corresponds to the interlayer distance of 3.342 Å , the  to determine the composition of the sample surface and more interestingly to determine the ratio of individual functional groups. Two local maxima are usually detected around ~284.4 eV for the C1s peak and around ~532.4 eV for the O1s peak. Maxima for N1s, S2s, and S2p peaks might also be found, showing the contamination of the sample by sulfur and nitrogen. The composition is very variable and depends on the level of oxidation of the sample . The dec2O, CO, and CO2.With simultaneous thermal analysis in an inert atmosphere, the temperature of exfoliation is investigated. The literature claims that the temperature of the exfoliation of graphene oxide is around 200 °C . The obtAtomic force microscopy (AFM) can be employed in order to study the thickness of the GO sample, therefore investigating the number of layers. It is known from the literature that a monolayered sample of GO has a thickness of 0.8–1.2 nm ,110. She2, CO, NO2, and NH3. Thanks to the oxygen groups decorating the basal planes and the edges, GO is capable of covalent or noncovalent interactions with various molecules. GO can be employed in catalysis for converting polluting gases during industrial processing. The elimination of such harmful gases can be performed by capturing and storing gases, catalyst reactions of gas conversion, or direct utilization [One of the biggest threats to the environment is air pollution caused by the industrial release of harmful gases such as COlization . Apart f2 [2 permeation performance [2 were developed, enhancing the diffusivity selectivity, solubility selectivity, and reactive selectivity [2S [2 [x [The functional groups of few-layered GO composites exhibit unique adsorption behavior towards CO2 ,115,116.formance . Multi-pectivity ,121,122.ectivity ,126,127.ectivity ,129, forectivity , H2S [13vity [2S ,132,133,y [2S [2 ,135,136,2S [2 [x ,138 can 2 conversion [2 reduction and solar energy harvesting.Thanks to the unique electronic properties, GO-based composites exhibit superior photocatalyst abilities for COnversion ,140. Hsunversion  reported−1 at 293 K [2+ ions is very low, even with oxygen groups on GO acting as active sites [GO exhibits high adsorption ability towards Cd(II), Co(II), Au(III), Pd(II), Ga(III), and Pt(IV) ,143,144.at 293 K . On the ve sites . With thve sites ,154,155.ve sites ,158,159.ve sites  reportedThe first possible application in this field is GO-based biosensors. GO-based biosensors rely on their preferred interaction with single-strand DNA (ssDNA) rather than double-strand DNA (dsDNA). This effect is caused by the effective hiding of nucleo-bases in dsDNA in a helical structure, which prevents GO from direct interaction with nucleo-bases ,162,163.Another interesting application is gene delivery, which is a promising way to treat genetic disorders, including cancer. The therapy uses gene vectors protecting DNA from nuclease degradation. GO sheets have been covered by polyethyleneimine (PEI) as a surface modifier for gene delivery into the cells. The delivery runs through complexation by electrostatic interaction and covalent conjugation for the loading of plasmid DNA (pDNA) ,164.Small-molecule drug delivery seems to be another promising medical application of GO. Small molecules of drugs can be attached to a GO surface using pH-sensitive linkers. A complex of doxorubicin and GO (DOX-GO) shows a release of DOX from GO dependent on pH due to higher solubility of DOX at low pH . MoreoveGO membranes may be used as ionic and molecular sieves or for selective gas transport. GO membranes were first introduced to the world by Nair et al. . It was As a reaction to Nair’s paper, Sun et al.  demonstr3N4 ceramic matrix was enriched by multilayered graphene or graphene oxide to study the influence of the addition on mechanical, tribological, and electrical properties. The addition of multilayered graphene caused higher hardness, modulus, and bending strength in comparison to graphene oxide addition. However, the addition of graphene oxide and multilayered graphene resulted in lower mechanical properties but better electrical and tribological properties [Graphene and graphene oxide are very promising materials for the reinforcement and general enhancement of mechanical properties of high-temperature materials. Some researchers studied the effects of graphene oxide on high-temperature materials such as metal alloys and ceramics. The mechanical resistance can be significantly improved by only 1 vol.% of GO. High energy ball milling was used to disperse graphene oxide powder in an aluminum (AlMg5) alloy matrix. Hot pressing was used to densify the obtained material . More froperties .Ordinary Portland cement (OPC) is one of the most used materials in the field of civil engineering thanks to the thirst for urbanization. The concrete is produced by mixing aggregates, binder (OPC), and water for hydration. Concrete has its advantages, such as unique compressive strength, as well as disadvantages, including poor crack formation resistance or low tensile strength . Researc2 during manufacturing [2 during the carbonation is magnesium oxychloride cement  [Magnesium oxychloride cements (MOCs) are promising alternatives to Portland cement. Let us note that OPC production is connected to high emissions of COacturing . An alte cement) . In orde cement) . Even th cement) .2 and toxic gases such as ammonia, acetone, formaldehyde, H2S, SO2, and NOx. There is also a possibility to convert CO2 by photocatalytic reaction using GO-based composites. Organic dyes and inorganic heavy metal ions in water represent another worldwide environmental issue that can be solved by using GO. There are also medical applications such as gene delivery, which is a very promising way of treating genetic disorders; drug delivery for targeting cancer; and GO-based biosensors. GO-based membranes can be employed as molecular and ionic sieves or for selective gas transport. In high-temperature materials, GO works mainly as an additive used for reinforcement and general enhancement of mechanical properties. Employing GO into building materials such as ordinary Portland cement or magnesium oxychloride can enhance their flexural and compressive strength as well as MOC’s poor water resistance.In this article, the history, synthesis, properties, and application of graphene oxide were reviewed. There are many GO derivatives, including graphene acid, fluorographene, and graphene oxide reduced by thermal or chemical reduction (TRG or CRG). Graphene oxide as well as its derivatives have plenty of various applications. Thanks to the oxygen functional groups on the edges and basal plane, GO can be used as a solution for environmental problems such as excess of CO