The use of graphene and its derivatives with excellent characteristics such as good electrical and mechanical properties and large specific surface area has gained the attention of researchers. Recently, novel nanocomposite materials based on graphene and conducting polymers including polyaniline (PANi), polypyrrole (PPy), poly  (PEDOT), polythiophene (PTh), and their derivatives have been widely used as active materials in gas sensing due to their unique electrical conductivity, redox property, and good operation at room temperature. Mixing these two materials exhibited better sensing performance compared to pure graphene and conductive polymers. This may be attributed to the large specific surface area of the nanocomposites, and also the synergistic effect between graphene and conducting polymers. A variety of graphene and conducting polymer nanocomposite preparation methods such as in situ polymerization, electropolymerization, solution mixing, self-assembly approach, etc. have been reported and utilization of these nanocomposites as sensing materials has been proven effective in improving the performance of gas sensors. Review of the recent research efforts and developments in the fabrication and application of graphene and conducting polymer nanocomposites for gas sensing is the aim of this review paper. These dications .Graphene is a p-type semiconductor that contains a larger hole to electron ratio concentration and has to pull an electron effect in a gas atmosphere . When grConducting polymers, including polypyrrole (PPy), polyaniline (PANi), polythiophene (PTh), and so on, have been used as the sensing materials of gas sensors. Conducting polymer-based gas sensors are more sensitive, with a shorter response time at room temperature, that tune both chemical and physical properties by using different substituents in comparison with most commercially available metal oxide (MO)-based gas sensors. Another advantage of conducting polymers is their synthesizing procedure is facilitated through chemical or electrochemical processes. Also, copolymerization or structural derivations can modify their polymer molecular chain structure .In recent years, the development of novel polymer nanocomposites has attracted significant worldwide research interest. The advantage of polymer-nanocomposite includes the value-added properties of the pure polymers without affecting their processability, inherent mechanical properties, and lightweight ,17,18. WNowadays, many studies investigated the performance of gas sensor-based graphene and its composites with metal oxides and polymers ,25,26,27A critical review of the published papers indicates that there is a gap in our knowledge about the comparison in preparation and sensing performance of graphene and different conducting polymers in the application of chemiresistive sensors for detecting various target gases. This article focuses on recent research efforts, developments, and approaches for the preparation of graphene and conducting polymer nanocomposites. The fabrication of chemiresistive gas sensors with graphene and conducting polymer nanocomposites is described along with a discussion of sensing performances.2, Fe2O3, ZnO, SnO2, and WO3. MOS materials possess good sensing properties, but require high operating temperatures [Sensors with accurate sensing performance have attracted much attention to monitoring and controlling emissions from various emitters . Gas seneratures . Theoreteratures . On the eratures . The seneratures ,43,45,46To enhance the sensitivity and selectivity of a resistive gas sensor, it is essential to understand the sensing mechanism. It is well known that the conductance of n-type semiconductors increases with a reducing analyte and decreases with an oxidizing one . The oppThe sensing performance parameters of the gas sensor include response, sensitivity, selectivity, stability, repeatability, response and recovery time, the limit of detection, and working temperature . The resFor reducing environments;o and Rg are the resistances of the sensor in background gas and the presence of target gas, respectively, and S is the response of the sensor. Based on the electrical response, different approaches are used to determine the sensitivity of a gas sensor. Sensitivity is the change degree in response to a certain concentration of target gas. The ability of a sensor to selectively respond is known as selectivity. Selectivity refers to the characteristics that determine whether a sensor can respond selectively to an analyte or a group of analytes. Repeatability is how much the gas sensor test results will be constant when they are tested in the same environment continuously and whether it can affect the working life of the sensor. Response time and recovery time are other important parameters for determining the performance of a sensor towards a specific gas. The response time and recovery time are defined as the time to reach 90% of the total change in resistance during exposure and removal of the target gas, respectively. The lowest concentration of target gas that can be detected by the gas sensor is known as the limit of detection (LOD). The temperature that can give the gas sensors its highest sensitivity is known as the working temperature [For oxidizing environments;perature ,53,54,55To detect the target gases, variety of materials such as conducting polymers ,57, carbNowadays, graphene and its derivatives have received attention owing to their unique properties such as good conductivity, large specific surface area, feasible adsorption of gas molecules, and their potential to be modified by functional groups as a sensing material for gas sensor fabrication ,65. On tSeveral studies reported that graphene and conducting polymer composites indicated excellent mechanical, thermal, gas barrier, electrical, and flame retardant properties in comparison with pure conducting polymers ,72,73,74Over the last few years research on incorporating graphene into polymer matrices to provide novel nanocomposite materials with enhanced electrical, thermal, mechanical, electrical, and other properties due to the large aspect and surface-to-volume ratios of the nanofiller has reseived extensive attention ,77,78,79The in situ polymerization involves chemical reactions. Normally in this technique, the nanofiller mixes with monomers in a solvent. The use of monomers can help to adjust the interactions between materials which makes possible intercalation and results in exfoliation and also compared to high molecular weight polymers, monomers diffuse into the galleries of the silicate more efficiently ,91. AlthThis section focuses on the synthesis of graphene and different conductive polymers  (PEDOT), etc.) nanocomposites and their application for gas sensing .The most widely used methods to synthesize graphene and PANi nanocomposites for the application of gas sensors are in situ chemical polymerization and solution mixing. In situ chemical polymerization was reported as an efficient method to uniformly disperse graphene oxide (GO) with a strong interaction between the GO and polymer matrix and . Typical2/rGO/PANi nanocomposite was synthesized by using the in situ polymerization technique [2 powder and NaOH were added in the same solution and then stirred to obtain the precipitate of SnO2/rGO/PANi composite [In situ chemical oxidative polymerization also was used for the preparation of graphene quantum dots (GQDs)/PANi ,107. SnOechnique ,109,110.The S, N: GQDs were prepared by the hydrothermal method in the presence of citric acid and thiourea. Ammonium persulfate (APS) was added to the mixture of aniline, 30 mL hydrochloric acid (HCl) and then transferred to the suspension of citric acid and thiourea. In the last step, the powder of S, N:GQDs/PANi hybrid was washed and dried in the oven. 2/GO/PANi by using the in-situ polymerization of aniline in the presence of TiO2/GO nanocomposite. Firstly, TiO2/GO composite was mixed with 50 mL of deionized water under stirring, and then aniline was added to the solution drop by drop in an ice water bath to obtain a hybrid material consisting of bulk reduced TiO2/GO/PANi [Junfeng Tian, et al. synthesized TiO/GO/PANi .4OH) solution firstly and then dissolved in N-methyl-2-pyrrolidone (NMP) while stirring. After that, graphene was added to the solution to make graphene-PANi nanocomposite [The most simple process method to prepare graphene and PANi nanocomposite is solution mixing ,112. Noromposite ,114.3 sensor based on rGO–PANi hybrid, which was synthesized using a simple, chemical oxidative polymerization method and coated on a flexible polyethylene terephthalate (PET) thin film was reported by Shouli Bai [3 exposure, good selectivity to some of the volatile organic compounds (VOCs) tested, and short response time and recovery time which were 20 s and 27 s, respectively at room temperature. GO-rambutan like PANi hollow nanosphere hybrid (GPA) for the detection of ammonia gas was prepared by the in situ chemical oxidation polymerization method and assembled on PET substrates as flexible devices [3, response and recovery time  and low detection limit of 50 ppb.The NHouli Bai . The com devices . The sen3 sensors based on /PANi loading on PTE and N-doped GQDs/PANi hybrid assembled on two different electrodes, silver (Ag) and aluminum (Al). The composite of S, N: GQDs and PANi lead to significant improvement in the response , and response and recovery time  at room temperature [3 gas sensor based on N-GQDs/PANi with Ag contact illustrated the best response of 110.92 compared to the sensor with an Al electrode (86.91) under 1500 ppm target gas at room temperature [Jaber Nasrollah Gavgani, et al.  and M. Hperature . The NH3perature .2/PANi composites were prepared by using the in situ chemical oxide polymerization for detecting different gases such as NH3 [4 [2S [2/PANi composite film exhibited 160% response to 20 ppm NH3, 9.1% toward 100 ppb H2S, and 26.1% to 100 ppm of CH4.The rGO@ SnOh as NH3 , CH4 [11s NH3 [4 , and H2S3 [4 [2S  at room 6H5–CH3) gas indicated the response of 11.6% and 90% toward 100 ppm and 5000 ppm C6H5–CH3 gas, respectively.The Gr/PANi nanocomposites were prepared by solution mixing  and in s3, CH4, C6H5–CH3, Benzene, and H2S. Among different NH3 gas sensors based on graphene and PANi nanocomposites, rGO–PANI hybrids loaded on a flexible PET thin film indicated the highest response of 344.2 to 100 ppm NH3 and the response time and recovery time were 20 s and 27 s, respectively [3. The enhancement of the sensing performance of the sensor based on rGO-PANi hybrid under NH3 exposure might be related to the acid-base deprotonation process of PANi nanoparticles, resulting in the selective response to NH3 gas.ectively . The sel3 gas sensor based on rGO/PANi hybrid sensing performance can be caused by the acid-base de-doping process of PANi nanoparticles and the synergetic effects between rGO and PANi [3.The enhancement of NHand PANi . This no3 gas sensor based on copper (II) tetrasulfophthalocyanine supported on a 3-dimensional nitrogen-doped graphene-based framework (CuTSPc@3D-(N)GF)/(PEDOT-PSS) nanocomposite  (PEDOT) nanocomposite. Yajie Yang, et al. ,118 prepomposite d.PEDOT:PSS is a widely used conjugated polymer due to its excellent electrical conductivity, high transparency, good processability, and low redox potential ,124. Fir2 gas compared to the sensor based on pure rGO [2 were also investigated. The PEDOT/RGO composite showed good sensing performance to NO2, higher operating temperature, and improved sensitivity. The gas sensor based on (CuTSPc@3D-(N)GF)/(PEDOT-PSS) nanocomposite indicated better response (5 and 53 times) and lower response and recovery times towards 200 ppm of NH3 compared with pure PEDOT-PSS and CuTSPc@3D-(N)GF [PEDOT, one of the most famous conducting polymers, attracted researchers’ attention due to its good conductivity, electrical properties associated with its low bandgap, and good stability ,127. Thepure rGO . The elepure rGO  and the 3D-(N)GF . 3 and NO2 gases. The gas-sensing performance of PEDOT/rGO nanocomposites prepared by in-situ polymerization technique revealed in contrast to other PEDOT/rGO nanocomposites, which were listed in 2 gas [As we can see in in 2 gas .2 gas exposure have been executed repeatedly. Yang et al. [2 gas, because of the synergistic effect between rGO and PEDOT. The gas sensor based on rGO and PEDOT nanocomposite under the various concentrations of NO2 gas  nanoparticles utilized the sol-gel method to obtain TiO2@PPy–graphene nanosheet (GN) nanocomposite  when exposed to 50 ppm of NO2 at room temperature. The gas sensor based on RGO-PPy composite decorated by TiO2 indicated a response of 102.2% toward 50ppm of NH3 [PPy is one of the most widely used conducting polymers in different applications due to its high conductivity, facile synthesis process, and great environmental stability . Graphenm of NH3 .2, humidity, NH3, and CO is indicated in 3 exposure when it is decorated with TiO2 nanoparticles [2 is an n-type semiconductor material with a bandgap of around 3.33 eV, which made it useful for sensing materials [2 nanoparticles can be a useful way to enhance sensing performance of rGO/PPy.The investigation of gas sensors based on RGO-PPy composites toward various target gases such as NOarticles . TiO2 isaterials . DevelopPolystyrene (PS)-modified graphene composites were prepared by using the solution blending method ,137,138.2 detection [2 exposure) compared to the pure PTh and graphene which might be attributed to synergistic effects between PTh and graphene [The in situ polymerization technique was used to prepare a hybrid of ethylenediamine-modified, rGO, and PTh and then the as-prepared hybrid was deposited on a flexible PET film to fabricate a sensor for NOetection . PTh attetection ,144. Thegraphene ,146,147.2TPP and graphene which were selected for being versatile, biodegradable, eco-compatible, recyclable (PS) [Joshua Avossa, et al.  designedble (PS) ,149 and −3 ΔR/R mg L−1 and the LOD of the sensor was 22.67 mg/L.Rey Alfred G. Rañola, et al.  investig3 exposure. 3 (1–1500 ppm). As we can understand from the tables and 3, the gas-sensing performance of PEDOT/RGO nanocomposites prepared by in-situ polymerization technique revealed in contrast to other PEDOT/RGO nanocomposites exhibited excellent sensing performance to NO2, and rGO/PPy nanocomposite indicated the highest response of 102.2% under 50 ppm NH3 exposure when it is decorated with TiO2 nanoparticles. Compared to various gas sensors based on graphene and conductive polymer nanocomposites such as graphene/PEDOT, graphene/PPy, graphene/PTh, and so on, graphene and PANi nanocomposite gas sensor shows the highest response for detecting NH3 gas. The enhancement of gas accessibility might contribute to the large surface area of the composite materials and also the combination of materials with various properties can result in a synergistic effect. Incorporating the merits of high conductive graphene sheets with the advantages of conducting polymers has attracted researchers’ attention to tap their novel characteristics because of the synergistic effect between them. The superior electrical properties of graphene materials, including high carrier mobility, and detectable change in their resistance after adsorption or desorption of gases, also contribute to the high sensitivity.The preparation methods and sensing performance of graphene and conductive polymer nanocomposites are discussed in this review paper. The most widely used methods to prepare nanocomposites of graphene and conductive polymers for the application of gas sensors are in situ chemical polymerization. Mixing these two materials exhibited better sensing performance compared to pure graphene and conductive polymers because of the large specific surface area of the nanocomposites, which might be attributed to the anchoring of conducting polymers on the surface of graphene sheets. According to the tables listed, rGO–PANI hybrids loaded on a flexible PET thin film indicated the highest response of 344.2 to 100 ppm NHThe most important mechanism that should be considered in graphene and conducting polymer composites is normally referring to non-interface dependent complementary behavior, which is known as a synergistic effect. A synergistic effect determines when various constituents in a composite material are separately in contact with the gas phase and serve a different purpose that is complementary of the other constituents in a material.The chemiresistors fabricated using the composite of graphene and other conducting polymers to date have received relatively little attention. On the other hand, there are only a few works that have studied the sensing performance of graphene/conductive polymer composites under various gases. Very few works have been reported on new preparation methods of this novel material and their application in gas sensors. The lower limit of detection for the given gas was not reported in most studies.Improving the large-scale production of gas sensors based on graphene/conductive polymer nanocomposites, enhancing the selectivity by functionalizing the sensing layer, and increasing the stability of the active layer should be considered in future studies.


Students are using file sharing sites to breach academic integrity in light of the Covid-19 pandemic. This paper analyses the use of one such site, Chegg, which offers “homework help” and other academic services to students. Chegg is often presented as a file sharing site in the academic literature, but that is just one of many ways in which it can be used. As this paper demonstrates, Chegg can and is used for contract cheating This is despite the apparent existence of an Honour Code on Chegg which asks students not to breach academic integrity. With pandemic led safety considerations leading to increased online teaching and assessment, the paper analyses data relating to how Chegg is used by students in five STEM subjects, namely Computer Science, Mechanical Engineering, Electrical Engineering, Physics and Chemistry. The results show that students are using Chegg to request exam style questions. They demonstrate that contract cheating requests can be put live and answered within the short duration of an examination. The number of student requests posted for these five subjects increased by 196.25% comparing the time period April 2019 to August 2019 with the period April 2020 to August 2020. This increase corresponds with the time when many courses moved to be delivered and assessed online. The growing number of requests indicates that students are using Chegg for assessment and exam help frequently and in a way that is not considered permissible by universities. The paper concludes by recommending that academic institutions put interventions in place to minimise the risk to educational standards posed by sites such as Chegg, particularly since increased online teaching and assessment may continue after the pandemic. This paper reports on the growth of how a single market leading file sharing website has been used for contract cheating purposes. The period of growth coincides with the Covid-19 pandemic and the associated necessary increase in online teaching and assessment within education.when academic lecture materials, notes, assessment tasks, answers, and responses are shared, swapped, and traded over Internet-based sites in fee, free, or barter (credit/exchange) arrangements”. Although student collaboration is often encouraged within an educational setting, a challenge with file sharing comes when students share files owned by a university with commercial providers. These providers then sell materials which they have no ownership claim over to other students. Often a barter system is used, with other students encouraged to upload more materials so that they can themselves get access to other resources and answers. As well as breaching copyright and instructor rights of intellectual property, this also has commercial implications for educational providers. Dixon and George  subjects, offering an analysis over a two-year period with reference to pre and post Covid-19 provision. The paper concludes by recommending that the sector works to address contract cheating through file sharing sites particularly as this relates to Covid-19.Many forms of assessment are susceptible to contract cheating. The literature in this field has revealed that an aggressive industry exists, aiming to implore students to cheat  number of questions posted in 18/19 was 8357 and in 19/20 was 14,578. Table The number of questions asked and answered on 1 March each year was also calculated. Eight thousand two hundred seventy-six questions were posted 1 March 2018 across all five subjects. These were answered 89.96% of the time. Thirteen thousand seven hundred nineteen questions were posted on 1 March 2020 and answered 85.57% of the time. Despite the slight drop in the percentage of questions answered, the raw numbers showed a substantial quantitative increase.Table The average number of questions per day per month was also calculated at a subject level and compared on a month-by-month basis. This showed a striking result. Between September and March, inclusive, the percentage increase never exceeded 32.27% for any of the subjects. Between April and August, inclusive, the smallest increase was 80.08% and the largest increase 343%. Table Figures For example, in Fig. Figure A further analysis considered the average number of questions asked per day in the September to March period and in the April to August period, compared over the 2 years. Between September and March, this showed an overall 12.68% increase between the years of the average number of questions posted per day per month, but between April and August the increase was 196.25%, which is a substantial difference. Furthermore, the average had dropped by 28.92% between the September 2018–March 2019 and April 2019–August 2019 periods, but increased by 87.74% between the September 2019–March 2020 and April 2020–August 2020 periods.Table Although Table Chegg do not provide the facility to trace requests directly back to an individual academic provider, or even a country of origin. On occasion it may be possible to work this out, but the way in which data is shown on the site makes this difficult. For example, some posts contain photos or screenshots of a problem that is likely to have been encountered in a standard textbook. Such standard questions could be in use at many institutions.Many questions list a number of available marks on them. Others appear to contain randomised variables. These are indicators that the questions are likely from online exams. Some questions contain both marks and randomised variables, as indicated by the Physics question example shown in Fig. Students have also been observed posting a series of requests one after another, most often where the questions are multiple choice or short answer format. Figure An interesting consequence of the Covid-19 pandemic is that there are many questions on Chegg whose themes include Covid-19. A selection of terms such as COVID, pandemic and coronavirus were used as search terms across all questions on Chegg from all subjects. In every case, Chegg returned 500 results, which is the limit of the number of questions returned by a search. This indicates that students around the world are being set questions on Covid-19 and that many of them are finding their way onto file sharing sites for third parties to answer on their behalf.This paper has reviewed how a file sharing website popular with students is used to facilitate contract cheating. There are many assessed coursework and exam questions posted and answered every day. The data shows a substantial increase in the number of questions asked and answered in the period from April 2020 onwards, largely matching with the move online of teaching and assessment. Given the number of exam style questions, it appears highly likely that students are using this site as an easy way to breach academic integrity by obtaining outside help.Using the fact that around 85% of questions asked are answered at least once, it is possible to approximate the number of questions answered each year. Based on Table To have a successful and growing business and to deliver a return to its shareholders, Chegg depends on a continual growth in the number of subscribers it has. Based on the growth in the number of questions asked, this also suggests an increase in subscribers and thus the number of students who have access to the answers.The apparent growth in student cheating also matches an increase in the market value of Chegg. Table In an interview, Chegg’s chief executive mentioned that they noticed a “sustainable growth” of the website starting from 15 March 2020 (Gelles Chegg does claim to have an Honour Code in place. In the Honour Code, it is stated that Chegg does not support fraud, cheating or breaches of copyright and suggests that materials may be removed or user accounts terminated if academic institutions contact them to open an investigation. There is little evidence that account termination has happened. In addition, it appears that there is nothing to stop students posting questions online and receiving answers within the time frame of an exam. There does not seem to be any manual approval of requests or periods of delay before questions are put live to be answered. People, including Chegg certified experts, appear to be ready and waiting to answer questions as they are asked. This seems to provide evidence that the Chegg Honour Code system is not working based on the volume of requests for assessed work that have been observed.Some individuals have stated that requests can be made to Chegg if their copyrighted teaching or assessment material is found online Murdoch . This maFuture action in this area is necessary. This includes awareness raising with both staff and students. Using contract cheating services is not victimless and this has to be communicated. Similarly, the messaging needs to provide consistent and clear advice that there are benefits to working with academic integrity and there are risks involved when breaching it. Staff should be encouraged to monitor file sharing sites for their assessments, but this can be difficult when questions are posted as images rather than text. Some form of automated monitoring, with immediate reporting to instructors if their assessments or exam questions appear to be found online, would be a useful development.Further research data could be collected from Chegg, covering more subjects over a longer time period. This investigation has focused only on STEM subjects, which typically have many questions that are mathematical or scientific in nature. This may make this area easier for contract cheating providers to give quick answers for these subjects than it would be for those that are more text based or descriptive. In addition, content analysis of the questions posted would also be useful, but that would most likely require an automated or machine learning based approach. Although it is the market leader, Chegg is not the only file sharing site. It would be instructive to see if the trends identified here extend more widely.Academic integrity breaches are happening and, as the data presented in this paper has demonstrated, such breaches are becoming more common as a result of Covid-19. These breaches do require a continued reconsideration of teaching and assessment methods. Even if face-to-face teaching returns, it is unlikely that this will ever now consistently take the same format it did prior to the pandemic. The genie is well and truly out of the bottle and there is no way to put the stopper back in. The entire academic integrity community, including but not limited to staff, students, academic institutions, quality bodies and commercial providers alike, needs to be ready and prepared to act.


Candida albicans, multidrug-resistant Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus biofilms, whereas MediHoney, polyhexamethylene biguanide (PHMB), and benzalkonium chloride (BZK) ointments failed to eradicate all biofilms within 2 hours. We assessed cytotoxicity by exposing L-929 fibroblasts to extracts of each ointment; Trypan blue exclusion was used to assess cell viability, and Alamar blue conversion was used to assess metabolic function. After exposure to PG+CAP and MediHoney, fibroblast viability was 96.23% and 95.23%, respectively (Trypan blue), and was comparable to untreated cells (98.77%). PHMB and BZK showed reduced viability . Metabolic activity results followed a similar pattern. Cytotoxicity of PG+CAP ointment towards erythrocytes was comparable to saline. PG+CAP ointment seems to be safe and can rapidly eradicate microbial biofilm; thus, PG+CAP ointment merits further in vivo testing as a potential antimicrobial wound ointment.Antiseptic wound ointments are widely used to treat dermal wounds that are microbially contaminated. Polygalacturonic acid (PG)+caprylic acid (CAP) is a novel combination that has been shown to eradicate biofilms. We developed a novel PG+CAP ointment and compared the biofilm eradication capability and cytotoxicity of PG+CAP with that of commercially available antiseptic wound ointments. We used a well-established biofilm model to quantitatively assess the eradication of organisms following exposure to the wound ointments for 2 hours. PG+CAP ointment completely eradicated  Antiseptic wound ointments are widely used to treat dermal wounds that are microbially contaminated. These ointments play an important role in inhibiting microbial biofilms because the ointments are broad-spectrum and do not encourage the development of antibiotic-resistant microorganisms. Quaternary-ammonium benzalkonium chloride (BZK) wound ointment was shown to generate an adequate environment for wound healing; it improved cell proliferation and cell activity and suppressed the multiplication of bacteria , 2. PolyStaphylococcus aureus (MRSA), multidrug-resistant Pseudomonas aeruginosa, Candida albicans, Escherichia coli, and Salmonella enteritidis) [As alternatives to both antiseptic and antibiotic ointments, natural plant-based agents have been shown to provide optimal biofilm disinfection without leading to antimicrobial resistance . MediHonritidis) . This stBenzalkonium chloride , polyhexamethylene biguanide , and MediHoney  wound ointments were purchased and used directly, while PG+CAP ointment was prepared in the laboratory as previously described . The oinP. aeruginosa (MDA #118), and C. albicans (MDA #117), as representative hospital-acquired infection pathogens from cancer patients. For testing, the organisms were grown from glycerol stock on trypticase soy agar+5% sheep blood (for bacteria) or on Sabouraud dextrose agar . Each organism was inoculated into Muller Hinton broth and diluted to 0.5 McFarland. Further dilutions were made as necessary for testing.Biofilm eradication testing was conducted using highly virulent clinical isolates of MRSA (MDA #120), multidrug-resistant 5 CFU/mL) and incubating at 37°C for 24 hours. All culture liquid was then removed, and disks were washed for 30 minutes in isotonic sterile saline to remove any remaining planktonic organisms. After washing, disks were exposed to ointments, control ointment base, and control by adding Muller Hinton broth and incubating at 37°C for 120 minutes. After exposure, viable organisms remaining on the surface of the silicone disks were assessed by disrupting biofilm via sonicating the disks in 5 mL of isotonic saline for 15 minutes. The resulting sonicate was serially diluted and quantitatively cultured onto trypticase soy agar+5% sheep blood for Staphylococcus aureus and P. aeruginosa or on Sabouraud dextrose agar for C. albicans. Each ointment for each organism was tested with six replicates. To ensure eradication was complete (no surviving dormant or persister cells) from biofilms for which no viable colonies were recovered following the exposure to ointments, we conducted regrowth experiments by first exposing biofilm-colonized disks to each experimental solution, then rinsing, and subsequently transferring the disks to fresh broth and reincubating for an additional 24 hours. Following the 24-hour regrowth interval, disks were sonicated and cultured as indicated above to determine whether any organisms remaining embedded in the biofilm were still viable.A well-established biofilm colonization model was employed to test eradication of pathogenic biofilms following 2 hours of exposure to different ointments . BrieflyMus musculus) cells were used in our study. Cell culture was performed according to fibroblast protocols as described by Rosenblatt et al. [2 until the cells formed a monolayer (60% confluent); then, a 2% extract of each ointment was added to its corresponding wells and incubated at 37°C with 5% CO2 for 24 hours. In the Trypan blue exclusion test, live cells with intact membranes exclude the Trypan blue dye whereas dead cells do not, and therefore, dead cells are stained with blue cytoplasm [μL HBSS+10% Alamar blue reagent and incubated at 37°C with 5% CO2 for 4 hours. Cell viability (absorbance) was determined at 570 nm using a microplate reader spectrophotometer, and the absorbance for each ointment was compared with that of controls.NCTC clone 929 areolar fibroblast mouse , incubating for 24 hrs, and then counting viable erythrocytes from 1 : 200 dilution in normal saline using a hemocytometer. Results from 5 replicates were collected for each ointment. 2% saline in whole blood was used as a control.U test to compare the performance of comparators. All tests were two-sided with an alpha level of 0.05. p < 0.05 was used to determine significance.To determine whether there was a significant difference between ointments and controls in the assays, the Kruskal-Wallis test was used. Pairwise comparisons were assessed using the Mann-Whitney C. albicans but was not able to fully eradicate biofilms of Staphylococcus aureus and P. aeruginosa. BZK and MediHoney did not fully eradicate biofilms of any of the tested pathogens. For MRSA, PG+CAP was significantly more efficacious than PHMB (p = 0.02), BZK (p = 0.002), and MediHoney (p = 0.002) in eradicating biofilms. PG+CAP eradicated significantly more P. aeruginosa biofilms than did BZK (p = 0.015) and significantly more C. albicans biofilm compared with MediHoney (p = 0.015). No growth was observed in the regrowth experiments for any ointments for which no viable colonies were recovered in the biofilm eradication assay, verifying that eradication was complete.p < 0.05). Results of the Alamar blue metabolic activity assay are shown in p < 0.05). Of the ointments assessed, PG+CAP was uniquely able to rapidly eradicate all representative biofilms without producing significant cytotoxicity relative to nonantimicrobial controls. The conventional antiseptic ointments (BZK and PHMB) were more cytotoxic and less broad-spectrum than PG+CAP. Previous studies reported that BZK was cytotoxic to fibroblasts, keratinocytes, and other epithelial cells . ElectroFibroblasts cells treated with PHMB generated discernable cytotoxicity in our study. These results are consistent with previous studies with PHMB on epithelial cells . MechaniDermal wounds have been reported to exhibit improved healing at acidic pH . The PG+These findings suggest that PG+CAP ointment is both safe and can rapidly eradicate microbial biofilm; thus, PG+CAP ointment merits further in vivo testing as a potential antimicrobial wound ointment with low toxicity for treating biofilm contaminated wounds. In this regard, future ultrastructural analysis of biofilms by electron microscopy following treatment with PG+CAP ointment would also be worthwhile.


Mutations in the gene coding for tau, MAPT, can cause FTLD-tau, directly linking tau dysfunction with disease . Another protein, TDP-43, comprises aggregates which are the primary hallmark of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD-TDP), and mutations in the gene coding for TDP-43, TARDBP, can cause disease . To model tau or TDP-43 proteinopathies, transgenic C. elegans have been generated that express the full-length human protein pan-neuronally. These worms exhibit significant uncoordinated movement on plates and impaired thrashing in liquid . However, tau- and TDP-43- expressing worms are not paralyzed; they still move their heads and have some motility on the plate  which are not captured in standard crawling or thrashing assays. To assay differences in total activity, we used a WMicroTracker ARENA System . The ARENA captures population level activity data by relying on optical interferometry, which uses a large array of infrared LED microbeams to detect both the movement and position of worms on a culture plate. Disruption of an LED microbeam by worm movement is recorded by repeat scans of the 6-well culture plate, and allows for real-time processing. The software identifies changes in the location of disrupted beams between scans and assigns an activity score based on differences identified between each consecutive scan (Simonetta SH). Both tau- and TDP-43- expressing worms had significantly less activity per minute than N2 . Further, we found the ARENA- assessed activity data recapitulated the relative severity of phenotypes among the strains as measured by motility assays. For example, both CK10 (tau V337M) and CK144 (tau WT) have significantly uncoordinated movement when crawling or thrashing in liquid, with CK144 having worse motility than CK10, due to its much higher burden of total tau protein expressed . Likewise, CK410 (TDP-43 WT) worms have slightly impaired motility compared with N2 when crawling on a plate, CK423 (TDP-43 M337V) are severely uncoordinated, and CK426 (TDP-43 A315T) have the most severe uncoordinated phenotype. The relative toxicities of these strains stem from the effects of the mutations, as TDP-43 protein expression is relatively even among these transgenic strains . Interestingly, the ARENA captures activity of these severely uncoordinated worms that move poorly in motility assays such as crawling on an NGM plate or thrashing in liquid . Therefore, ARENA assessment of aggregate activity may be a more accurate metric for capturing non-locomotor movement of C. elegans that are severely uncoordinated.Aggregates of the protein tau are the hallmark of several neurodegenerative diseases including Alzheimer’s disease, frontotemporal lobar degeneration (FTLD-tau), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), Pick’s disease, and chronic traumatic encephalopathy (CTE) . The plate was placed in the ARENA 15 minutes before starting the run to allow worms to acclimate. 14 activity scores were collected per strain over 60 minutes. Statistical analysis was performed with GraphPad Prism 8.All worms used were staged by way of timed egglay, and grown at 16Strains UsedN2 BristolbkIs10  IIICK10 bkIs144  IVCK144 bkIs410  IICK410 bkIs423  IVCK423 bkIs426  IICK426


Among a growing body of research that examined the contradictory role of written corrective feedback (WCF) in development of L2 writing accuracy, this study investigated the possible impact of focused metalinguistic WCF on discourse markers (DMs) in writing performance of an intact group of 42 Iranian English as a Foreign Language (EFL) learners over an eight-week period. In an authentic, situated, and personalized learning platform, giving and receiving WCF were made possible only through the mobile-mediated application of WhatsApp. Before participants wrote on selected elicitation topics, they had taken part in a 2004 version of Oxford Preliminary Test in order to be screened for their initial differences in writing performance. After receiving metalinguistic WCF on their scripts, participants were required to work on the coded feedback and try to eliminate the DM errors in their revised writing assignment. After collecting the scripts over an eight-week period, the content of written assignment was thematically analyzed using NVivo 21 Software for the additive, adversative, causal and temporal DMs, following Halliday and Hasan’s  typology. In a convergent mixed-methods design, the content analysis of the qualitative data showed a larger distribution of additive DM than adversative, causal, and temporal DMs in all participants’ written scripts. Exploring the possible impact of metalinguistic WCF on improving the DMs accuracy, analysis of the frequency count data with Statistical Package for the Social Sciences (SPSS) multivariate Chi-square test reported the fluctuation and unsystematic patterns of distribution for four types of DMs with no sign of significant long-term improvement in DMs accuracy after receiving metalinguistic WCF. These findings implied further research on practicing alternative WCF strategies focused on variety of error types in actual and virtual L2 writing environments. Many studies verified the viability of WCF in improving L2 learners writing  in second/foreign language (L2) contexts does not protect any language teachers from losing sight of how to interpret the contradictory research findings and how to take actions to apply them in real classroom context. For many L2 teaching professionals, the critical concern about WCF has never been whether it is useful, but In the absence of serious examination of WCF long-term efficacy, well-designed and valid experimental studies, the challenge over WCF benefits still persists. Within the WCF advocates party, a group of researchers have been interested in the extent to which different WCF strategies and their amount of explicitness may have divergent impacts on L2 writers’ accuracy  pandemic. Online initiatives, resources and educational programs have emerged and evolved quickly in the absence of face-to-face teacher mediation, wherein the L2 writers can still benefit from WCF. It is through computer-mediated writing assignment or online classroom tasks that the teachers’ suggested notes or corrective feedback can easily be transmitted to the L2 writers. Therefore, it is believed that using modern technological devices such as smart phones, iPads or even desktop computers might create a platform to bring to the L2 learners the advantages of immediate and more favorable types of WCF  learners progressed in fluency, communicative abilities, and their confidence in using French, they commonly failed to master French grammar use even after years of extensive exposure  slims the chance of bewilderment that students will usually experience if they fail to recollect the received indirect feedback; (2) grants them a toolkit to predict and prevent future errors; and eventually, (3) seems more intriguing and immediate to the students in writing classrooms  WCF if they have to attend to all committed errors at the same time. While to several researchers, unfocused WCF is detailed and authentic; many more blamed it as an unsystematic WCF strategy which overloads L2 writers’ working memory capacity  has made entrance to most educational settings, especially L2 learning/teaching context. So far, the power of wireless technologies has improved markedly, “especially with smart mobile phones which have incorporated the functionality of hand-held computers and audio-video recorders and players”  consented to voluntary participation among whom three volunteers were excluded after administering the Oxford Preliminary Test (2004 version) as the placement test in this study. Within the age range of 19 to 45 and average of 28, the 42 candidates enrolled in a virtual course of English paragraph writing at a private language institute in Karaj, Iran which lasted for eight consecutive weeks. The participants were undergraduate university students majoring in engineering (27%), medical sciences (22%), accounting (22%), Russian literature (16%) and architecture (13%), whose general English proficiency was determined at advanced levels of C1 and C2, trusting their range of obtained scores (48–60) on the OPT.OPT is a standard test of general English proficiency with a six-point rating scale. As stated in www.oxfordenglishtesting.com , OPT “meα = 0.883). Eventually, 42 students whose OPT scores assigned them to levels of C1 and C2 were selected as the final research sample.At the outset of the experiment, to minimize the odds of initial differences among the participants in terms general English proficiency, the researchers administered a 2004 version of OPT with 100 multiple-choice items and reasonable measure of inter-item reliability  whose scores were below the advanced level of language proficiency . The final 42 selected candidates were informed that in the following 8 weeks they were required to write a 150–200 word paragraph on every selected topic and send it to the instructor through WhatsApp Messenger. Next, they received detailed instructions on four types of DMs  referred the students to the following explanations in the DMs glossary sheet:and, also, moreover, in other words, is used to repeat or emphasize the previous information or add relevant new ideas or expressions to them.ADD = Additive DM, such as yet, though, however, in any case, instead, is used to express contrasts and comparisons between sentences or corrections in relation to foregoing discourse.AD = Adversative DM, such as so, then, therefore, because, is used to signal the results or consequences of what is being stated.CD = Causal DM, such as next, when, secondly, is used to reflect the chronological, logical or sequential relationship between discourse units. No further error categories were corrected or received coded feedback.TD = Temporal DM, such as Once a DM error was located by the researchers, it was highlighted and an abbreviation above the error , including and, however, before, so, if, 10 of which were additive DM. Among additive DM, and was overused. Table Imagine a day without the Internet, smart phones or computers. How would your life most likely become?As Table n = 14) were used more reasonably and frequently. Moreover, AR started to use less frequent DMs, such as initially, since, and as well as which show some degree of adjustment in her writing performance. Still, AR used more additive DM (n = 7) than other three DM types. Finally, as Table Why do most people still want to live in cities rather than country sides?In Table n = 0), the instances of other types of DMs, such as although, because of, and, also, and so were accomodated accurately with similar frequency rates (n = 14). To sum up, the frequency distribution of four types of DMs in AR’s writing was different in every session, with no sign of considerable improvement over 8 weeks of receiving metalinguistic WCF. Similar unsystematic and fluctuating patterns of DMs distribution were retrieved and reported in other participants’ writing.According to Table obligatory occasion analysis). For instance, in a written script, the three correct usage of the additive DM from 10 obligatory occasions was calculated as 30% accuracy rate.Following Ellis and Barkhuizen , accuracFor frequency analysis of the collected quantitative data, the IBM SPSS 21 descriptive statistics was deployed. The obligatory occasions for the DMs were identified and noted in all the written scripts by each candidate on the eight assigned writing tasks. The interrater reliability was checked across the current researchers’ ratings to ensure the credibility of the content analysis and it had the index of 0.815 in terms of Cohen’s kappa coefficient. The measures of mean and standard deviation for four types of DMs were summarized in Table the extent to which metalinguistic WCF affects EFL learners’ accuracy of four types of DMs in their writing performance, the measures of mean and SD demonstrated fluctuating patterns of distribution across four types of DMs, despite the participants constantly using additive DM more than the three other DM types along eight sessions of metalinguistic WCF. In other words, through the treatment sessions, no considerable progress in the DMs accuracy could be seen in participants’ writing after receiving metalinguistic WCF. Figure As it can be seen in Table As Fig. how metalinguistic WCF would affect EFL learners’ accuracy of DMs in their writing performance over an eight-week period, or in another terms, the significance of fluctuations in DMs accuracy along the metalinguistic WCF intervention sessions, the frequency pattern for every type of DMs was cross-examined in a contingency table , p = 0.000, Cramer’s V = 0.910 (indicating a strong effect size)]. To sum up the findings, the frequency counts of the four types of DMs showed different distributions in the participants’ writing, with the additive DM as the most frequent (n = 4651) and temporal DM as the least (n = 1393) overall. However, such fluctuating patterns of occurrence seemed consistent and non-significant along the eight-week period of treatment rendering no accountable sign of improvement in participants’ writing performance through and after receiving metalinguistic WCF.Summarized in Table This study aimed at investigating the extent and the quality of metalinguistic WCF possible impacts, specifically focused on EFL learners’ use of discourse markers in a mobile-mediated language learning platform. Qualitative data analysis in this study indicated a considerable divergence in the frequency patterns of four types of DMs  in the participants’ writing performance. To be precise, the additive DM had an outnumbered appearance over adversative, causal and temporal DMs. Much to the chagrin of the current researchers, however, despite a significant difference in the frequency distributions of the DMs, the statistical data analysis failed to support a meaningful improvement in the participants’ DMs accuracy along an eight-week period of receiving metalinguistic WCF. There is a growing body of research which still examines such nuances and niches in applying WCF. Despite ample empirical evidence, it is still unclear whether specific error types are more sensitive to WCF than others (Bitchener, temporarily but they hardly advance their internal grammar which is acquired and internalized over time and only through natural and extensive exposure to L2. In other words, regarding the constructive role of feedback, positive evidence is a trigger for progressive change; negative evidence seems irrelevant in a long shot.Conforming to Truscott’s  stark dito correct or not to correct their students’ written performance are left in the middle of contention.There have been abiding debates between those who strongly support the advantages of WCF to natural improvement of L2 learners’ writing performance and those who are against them. Likewise, Guénette  argued tScholars like Truscott and Hsu , who belIn L2 research domain, several studies found corrective feedback even harmful rather than simply ineffective (Farrokhi et al., Although attempts were made to minimize the probable lapses in research design, data collection and content analysis in this study, there are some limitations and implications which should be pointed out once further research is designed in the future. The focus of metalinguistic WCF in this study was only on locating and responding to discourse markers, which can be both a source of strength and a cause of restraint to the generalizability of the findings. Adopting DM lenses made it possible to focus on the EFL learners’ accuracy of cohesive devices; however, further research is needed to estimate the extent to which the findings in this study are applicable to other non-treatable error categories as well.Further research is also needed to investigate whether alternative means of data collection, such as writing tasks of different genres or various strategies of WCF might change the algorithm of DMs occurrences in EFL learners’ writing. It should also be noted that the participants in this study were Iranian EFL learners at the advanced level of English language proficiency who studied English in the formal educational setting and had received some earlier instructions to the use of DMs in academic English writing and grammar courses. Further research seems necessary to determine whether a variety of WCF strategies would help the elementary or less proficient EFL learners to develop accuracy in using DMs in their writing performance.Finally, as several incompatibilities were earlier reported between the WCF empirical research findings and real classroom practice (e.g., Hobbs,


Graphene and its derivatives, with their unique two-dimensional structures and excellent physical and chemical properties, have been an international research hotspot both in the research community and industry. However, in application-oriented research in the oil and gas industry they have only drawn attention in the past several years. Their excellent optical, electrical, thermal and mechanical performance make them great candidates for use in oil and gas exploration, drilling, production, and transportation. Combined with the actual requirements for well working fluids, chemical enhanced oil recovery, heavy oil recovery, profile control and water shutoff, tracers, oily wastewater treatment, pipeline corrosion prevention treatment, and tools and apparatus, etc., this paper introduces the behavior in water and toxicity to organisms of graphene and its derivatives in detail, and comprehensively reviews the research progress of graphene materials in the upstream oil and gas industry. Based on this, suggestions were put forward for the future research. This work is useful to the in-depth mechanism research and application scope broadening research in the upstream oil and gas industry. With the continuous growth of population and the rapid development of economy, the global energy demand is increasing. Oil and natural gas, as the most important current energy sources for human society, will not be replaced on a large scale, at least during the first 50 years of the 21st century. The oil and gas industry is a multibillion-dollar market that affects the lives of anyone who has ever driven a car, used electricity, walked on asphalt-paved roads or used polymer products such as plastics [In recent years, nanomaterials application research in biology, medicine, electronic engineering and other fields has made rapid progress, which also provides new ideas for the development of the upstream oil and gas industry. The relatively high cost of nanomaterials is a major challenge for their application in the oil and gas industry, but scholars and oil companies around the world are still actively carrying out research on the applications of nanomaterials in the oil industry. The most widely studied nanomaterials are carbon nanotubes, carbon nanofibers, nano-oxides, and nano-clays .2 hybridized, and there are dangling bonds on the edges. However, because graphene needs to be stable in the natural environment, the hanging bonds on the edges of such nanoscale graphene sheets are occupied by other chemical bonds, therefore, in practical applications, it is always a three-dimensional graphene material composed of nanoscale graphene sheets. In this paper, the application of graphene and its derivatives in petroleum engineering is reviewed, and their development directions in the upstream oil and gas industry are proposed.As a special nanomaterial, the application of graphene and its derivatives in the field of oil and gas industry has attracted more attention. However, compared with its extensive application in other fields , the application of graphene in oil and gas exploration and production is still at the initial stage. Although its research time is short, the effects of graphene and its derivatives in oil exploration and development are obvious, so many scholars and engineers believe that they will have a better application prospects in the upstream oil and gas industry. Although in theory, graphene should be large in size and large in area, each carbon atom is sp2 hybridization. Its basic structural unit is the most stable benzene-like six-membered ring structure. Its theoretical thickness is only 0.35 nm, which is the thinnest two-dimensional material discovered so far [In 2004, Novoselov and Geim at the University of Manchester in the UK obtained the first graphene sheet by a mechanical exfoliation method, and since then graphene has become a research hotspot in the scientific community around the world . The uni4 cm2·V−1·s−1, which is twice that of indium antimonide material  and 10 times higher than that of the commercial silicon wafers. Under certain conditions , the mobility can even be as high as 2.5 × 105 cm2·V−1·s−1. The thermal conductivity of graphene can reach 5 × 103 W·m−1·K−1, which is three times that of diamond. In addition, graphene has excellent chemical stability and adsorption properties [Graphene has many excellent physical and chemical properties. For example, the strength of graphene is the highest among the tested materials, reaching 130 GPa, which is more than 100 times that of steel. Its carrier mobility is 1.5 × 10operties ,7,8,9.2 hybrid state to sp3 hybrid state, and then peeled layer by layer [Graphene derivatives generally include graphene oxide (GO), reduced graphene oxide (rGO), graphene quantum dots (CQDs), doped graphene and modified graphene, among which graphene oxide is the most widely used graphene derivative. Graphene oxide is a kind of single-layer two-dimensional material, obtained by the oxidizing and intercalating modification treatment of graphene, which changes part of carbon atoms from spby layer . The strby layer ,12,13,14The industrial applications of graphene and its derivatives are mainly in the fields of surface coating and preparation of nanocomposites, in which graphene and its derivatives participate the whole process mainly in the dispersion form. The research on the behavior of graphene and its derivatives in water is involved in the fields of chemistry, materials science, environmental science and biomedicine ,16. In t−1, GO began to coagulate rapidly. Furthermore, the influence of divalent metal ions on the average electrophoretic mobility and the hydraulic diameter was stronger than that of univalent metal ions. Moreover, the humic acid had a significant effect on the stability of GO in the solution. When the concentration of humic acid increased from 0 to 10 mg·L−1, the hydraulic diameter of GO decreased from 500 nm to 250 nm, and the stability was significantly improved [The solubility of graphene in water is very low. Due to the effect of van der Waals forces, it easily forms agglomerates or even accumulates to form turbostratic carbon in aqueous solution . The zetimproved . In addiimproved .With the rapid growth of the application scope and usage of graphene materials, it is inevitable they will leak into the environment at some point during the whole cycle of production, storage, transportation, use, disposal and recycling. Although graphene nanomaterials have relatively good biocompatibility, they still have certain biological toxicity. Therefore, the impact of graphene nanomaterials on organisms and the environment has attracted more and more attention . The oilCytotoxicity is one of the important indexes used to evaluate the safety of pollutants. Studies have shown that graphene nanomaterials have certain cytotoxicity, and their toxicities are closely related to their physical and chemical properties and the types of cells, and it also has a significant concentration dependence. The mechanism of the cytotoxicity of graphene is not very clear at present, but studies have shown that oxidative stress and inflammatory reaction are the main mechanisms leading to cell death. Graphene materials have high surface activity, which can produce a lot of reactive oxygen radicals (ROS) after aggregation on the surface or inside of cells. These ROS further lead to DNA fragmentation, cell membrane damage and mitochondrial dysfunction . Qu et aCaenorhabditis elegans, which can damage its gonad development [Graphene materials have also shown some toxic effects on animals. At present, most of the studies focus on mammals such as rats and mice. The lower protozoa and nematodes, as well as zebrafish and other aquatic animals have also been studied. The toxicity of graphene materials to animals is closely related to its action position, action mode and action concentration, as well as the size of itself and the types of surface functional groups. The toxicity of graphene to mammal is manifested as low acute toxicity. GO is more toxic to the lungs of mammals than graphene, however, the surface modification can avoid the toxic effects of GO. The size of graphene material is also a major factor affecting its toxicity ,29,30,31elopment . Chen etelopment .Arabidopsis thaliana, and found that GO had no significant effect on seed germination, seed development, seedling root development and flowering time. The above studies indicate that the toxic effect of graphene on plants may be related to oxidative stress, but the detailed mechanisms need further study [Raphidocelis subcapitata from the aspects of ROS, membrane damage and chlorophyll content, and the results showed that GO could lead to the increase of ROS and membrane damage in green algae cells, and the accumulation of graphene would also affect the lighting efficiency of green algae [Chlorella vulgaris and found that GO could accumulate on the surface of algal cells, significantly reduce the permeability of cell membrane, and cause a degree of extent oxidative stress, resulting in algal cells damage [Graphene materials are toxic to both terrestrial plants and algae. Begum et al. studied the toxic effects of graphene on a variety of vegetables, from the aspects of growth, biomass, shape, cell death and active oxygen level of their roots and buds. The results showed that higher concentrations of graphene could significantly inhibit plant growth and biomass increase. In addition, different kinds of plants and different parts of plants have different reactions after exposure to the action of graphene . Zhao ster study . Nogueiren algae . Ouyang s damage . The aboEscherichia coli while showing less cytotoxicity. Graphene paper sheet obtained by simple vacuum filtration using graphene suspension also had good antibacterial effect [In the aspect of antibacterial activity, Hu et al. first reported the antibacterial activity of GO and rGO, and found that the graphene-based nanomaterials can effectively inhibit the growth of l effect .In conclusion, the toxicity of graphene materials to cells, animals, and plants is relatively low, and they can show good biocompatibility after surface modification. Graphene has a good antibacterial effect on microorganisms. However, Schinwald et al. found that GO could interact with proteins in the plasma to form GO-protein composite particles. Graphene sheets could easily become inhalable particles, enter the lungs and deposit into the alveoli, and produce toxic effects on the lungs, causing severe pulmonary fibrosis and cysts. In addition, the particles may accumulate in the lung, liver, spleen and kidney. What makes matters worse is that it cannot be removed from the kidney . TherefoExploratory research for applying graphene and its derivatives in the fields of well working fluids, chemical enhanced oil recovery, heavy oil recovery, profile control and water shutoff, tracer, and oily wastewater treatment, etc., was conducted in the past three years. Meanwhile, they have also been applied in tools, sensors and pipelines. Although the above research is still in the initial stages, we have reasons to believe that graphene and its derivatives will certainly provide new breakthroughs in their application in the oil and gas industry, because of their widely application research in many fields such as biomedicine, nanotechnology, electronics, photonics, heat transfer and so on, through which the similar mechanisms could be found.Drilling engineering is an important step in establishing a connection channel between the ground production system and the underground reservoir, which refers to the rock stratum with pores, fractures or holes, where oil or natural gas are stored and flow. The performance of the working fluid directly affects the construction work. Drilling fluid in the broad sense is all fluids  that help to produce and remove cuttings from the wellbore during drilling process. The functions of drilling fluid mainly include flushing the bottom of the well, carrying cuttings, balancing formation pressure, cooling and lubricating the drill bit, stabilizing the well wall, protecting oil and gas reservoir, and transmitting the ground power, etc. Monteiro et al. pointed out that graphene particles can effectively improve the fluid fluidity, filtration, rheology, stability, lubricity, electrical properties, thermal properties, viscosity and other properties, therefore it can be added to drilling fluid, completion fluid, cementing fluid, etc. . This seDrilling fluids can be filtered into the reservoir at a certain temperature and pressure difference. The filtration loss property of a drilling fluid refers to the property of whether a drilling fluid can be easily filtered into the formation or not. A large amount of filtrate invading into the reservoir will block the oil/gas flow channels and cause damage to the reservoir. At the same time, the thick filter cake  may cause drilling accidents such as undergauging of holes, increased friction, bit freezing, and well leakage. Therefore, it is necessary to add a fluid loss control agent to drilling fluids to ensure the formation of high-quality mud cake and prevent the filtrate from invading the formation during the drilling process .Submicrometer-thick membranes made from graphene oxide can be completely impermeable to liquids, vapors, and gases, including helium, but these membranes allow unimpeded permeation of water . If it cGraphene oxide, as a kind of nanomaterial with the same lamellar structure as graphene, is more suitable for use in water-based drilling fluid than graphene because its surface is rich in polar groups and it has good water dispersibility . During 2 and the diameter of 9 cm at room temperature and 0.689 MPa pressure for 30 min. Compared with standard bentonite , the best filtration loss property was achieved when the mass ratio of flaky GO to powdered GO was 3:1, and the results were that the API filtration loss was 6.1 mL and the filter cake thickness was 20 μm [Kosynkin et al. believed that even if GO was added to a water-based drilling fluid at a dosage as low as 0.2 wt %, it still showed good filtration loss control performance. American Petroleum Institute (API) filtration loss is a commonly used parameter to describe the filtration performance of drilling fluids. API filtrate loss refers to the filtration loss of drilling fluid permeated through the filter paper with the cross-sectional area of 45.8 cmas 20 μm . Xuan etas 20 μm .Graphene has excellent self-lubricating properties, so it can be used to improve the lubricity of drilling fluids. Zhao et al. studied the lubrication and wear properties of graphene particles as lubricant additives added into the PAO4 lubricating oil by means of a UTM-2 tribometer via ball on plate contact reciprocating sliding. The results showed that the friction coefficient and the wear rate can be reduced by 78% and 95%, respectively, when graphene was added .Taha et al. developed nanographene particles that can enter the pores of metals where they crystallize under high pressure to form a protective film, and prevent the formation of balled bits. The tests showed that the extreme pressure lubrication coefficient of water-based polymer drilling fluid could be reduced by 80% after adding graphene with a volume fraction of 1–5%, while it as only reduced by 30–40% after the addition of a common ester-based lubricant. In addition, graphene also can significantly improve the reservoir protection performance of the well completion fluid. After the interaction of graphene-based completion fluid with the reservoir, the reservoir permeability recovery rate reached 41%, while it was only 5% for a conventional completion fluid. After adding 2% graphene into the drilling fluid of a pilot well in Myanmar, the penetration rate increased from 3.0–4.0 to 9.0 m/h, while the friction resistance decreased by 70–80%. Meanwhile, the bit life was extended by 75%, the bit wear was small, and no mud was found on the bit surface. The wear rate of the drill bit was reduced, and no balled bit were seen ,53.Furthermore, Liu et al. pointed out that GO had a better effect on improving the lubricating properties and friction reduction of drilling fluid than graphene. A field application test in Northeast China showed that when 0.075 wt % GO was added to an oil-based drilling fluid, the lubrication factor of the drilling fluid was reduced by 15.6%, the reduction rate of the friction coefficient was increased by 24.3%, and the aluminum disk wear was reduced by 20.5% .Halliday et al. pointed out in their patent that adding graphene particles to the drilling fluid could improve the rheological properties of drilling fluids, such as plastic viscosity, yield pint, gel strength, apparent viscosity, and so on. Using graphene particles 80 mesh size (the particle size distribution was greater than 65%) they could prepare a drilling fluid system with excellent rheological properties, while particles of 120 mesh could be used to prepare a stuck-freeing spotting fluid .Borehole wall stability refers to the ability of the face of a well to maintain its original state. Shale inhibitors are often used to inhibit shale expansion and maintain borehole wall stability. Graphene and its derivatives can also improve the shale stability ,57,58. ACementing fluid is the working fluid used in well cementation. During the process of cementing, the cementing fluid is injected from the casing pipe to the annulus space  pointed out in their patent that both nanographene and nano-GO can be used as crosslinkers for fracturing fluids. When a composite crosslinker system based on the above materials and crosslinkers was used to conduct fracturing, the shear resistance of fracturing fluids was improved by the synergistic effect between nano-GO or nanographene and cross-linking agents . Lv et ant areas . The aboFossil energy sources such as oil and natural gas, are non-renewable energy forms. How to maximize the oil or gas recovery is of great significance to the sustainable development of the global economy, and the enhanced oil recovery (EOR) technology has attracted worldwide attention, in which chemical enhanced oil recovery (CEOR) is one of the most effective ways. The construction of oil flooding systems based on new materials has always been the main direction of the development of chemical flooding for oil recovery. The application of nanoparticles in CEOR, which has developed rapidly in the past two decades, provides the basis for the application of graphene materials in CEOR ,80,81,82Nanofluid flooding technology shows great application prospects in CEOR. The term nanofluid refers to a homogeneous liquid obtained by highly dispersing nanomaterials  in water or other liquid phases (such as ethanol). Compared with the conventional chemical flooding , the nanofluid flooding mechanism is more diversified, including conventional mechanisms such as mobility control, low interfacial tension, wetting reversal, as well as the unique interfacial effects of nanoparticles ,84,85.+ cations acted as a bridge between the two negatively charged surface of the sandstone and GO sheets, and the bridging effect of Na+ was not as much as the effect of pH at low salinities [It is found that graphene oxide can be used in CEOR due to its surfactant-like properties, such as changing wettability, emulsifying property and reducing interfacial tension. Radnia et al. studied the adsorption behavior and mechanism of GO on the sandstone surface  in improving oil recovery, as shown in Namin et al. pointed out that functionalized nitrogen-doped graphene could disperse stably in water in the condition of high salt and high temperature and could reduce the oil/water interfacial tension by 49.2%. Wettability reversal could be achieved by its adsorption on sandstone and limestone surfaces. In addition, when functionalized nitrogen-doped graphene was used as oil displacement agent, the oil recovery could be increased by 16.42%, which they believed was mainly due to its ability to reduce the interfacial tension .2 nanohybrid by the sol-gel method, and pointed out that the Pickering emulsion stabilized by this nano-porous graphene/SiO2 nanohybrid remained stable in a reservoir with a salt content of 1%, the temperature of 25–120 °C, and the pH value of 7–10. It is also pointed out that the composite material can reduce the oil/water interfacial tension, improve the rheology of the injecting fluid, and could be used in chemical flooding [AfzaliTabar et al. prepared rGO/SiOflooding . Tajik eflooding .Polymer flooding, which employs polymers as flooding agents, is a commonly used technique to improve oil recovery. The oil displacement mechanism is to reduce the water-oil mobility ratio and increase the sweep efficiency of the flooding fluid, thereby improving the crude oil recovery ,96. The Haruna et al. prepared graphene oxide/partially hydrolyzed polyacrylamide materials (GO/HPAM) and studied the influence of GO nanosheets on the rheological properties and thermal stability of HPAM. The results show that hydrogen bonds were formed between GO and HPAM. The addition of GO significantly improved the long-term thermal stability of the material, as well as the storage modulus and loss modulus of HPAM. In addition, GO/HPAM composite has good performance under high salt conditions . Lyu et 2 foam flooding to improve oil recovery, in order to improve the foam stability, the stabilizer needs to be quickly migrated onto the surface of the liquid film to form a stable foam boundary, and slow down the drainage of the liquid film of the foam [In the process of COthe foam . The comthe foam ,107,108.the foam ,110,111.2/water emulsion, as shown in 2 flooding. The results show that graphene oxide played a stabilizing role in the CO2/simulated seawater foam system due to the formation of hydrogels and graphene oxide accumulation effect. rGO could not stabilize the foam due to its small size, which increased the hydrophilicity. rGO with the content of 13–22% could not stabilize the foam, which was different from the results obtained by Liu. This may be due to the high reduction degree of the particles, and the increase of oxygen content would enhance the hydrophilicity and reduce the CO2-affinity [Liu et al. demonstrated that partially reduced graphene oxide (rGO) can effectively stabilize COaffinity .Thermal oil recovery is the main method of heavy oil production, which refers to the method of injecting heat from the ground to the stratum or generating heat underground to achieve underground crude oil extraction ,115,116.2O3, NiO, CuO, ZnO, Al2O3, TiO2 and WO3, Fe2O3 exhibited the best viscosity reduction effect. However, if the same heavy oil viscosity reduction rates were achieved, the price of GO was 10–15% lower than that of Fe2O3. Therefore, they claimed that GO not only had a significant viscosity reduction effect for heavy oil, but also was economically feasible, and can be applied to all methods of heavy oil production  [Elshawaf et al. studied the application of GO in heavy oil recovery. They pointed out that when the temperature was 40–70 °C and the GO dosage was 0.02–0.08 wt %, the viscosity of heavy oil can be significantly reduced by 25–60%. By comparing the viscosity reduction of heavy oil treated by other nano particles, such as Fed, etc.) ,125.3O4) have strong magnetic loss to microwave. Therefore, by combining graphene with magnetic nanoparticles, graphene/magnetic nanocomposites with both electrical loss and magnetic loss can be obtained, which is conducive to widening the absorption band and impedance matching, and improving the microwave absorption capacity [The use of microwave irradiation to extract heavy oil has the advantages of continuous heating, being unaffected by buried depth, easy to control, and a low-level of environmental pollution. At present, many countries and oil companies are carrying out relevant research and experiments. However, due to the small dielectric constant of heavy oil, the penetration depth of microwave in heavy oil reservoirs is limited, which affects the viscosity reduction effect ,128,129.capacity ,137,138.Xu et al. prepared magnetic graphene oxide (MGO) by a self-assembly method and conducted microwave-assisted enhanced recovery research. The results showed that MGO had good dispersibility in water. With the increase of microwave radiation time, the dispersibility weakened and formed magnetic reduced graphene oxide (MrGO), showing better lipophilicity and better microwave absorption ability when compared with MGO. MGO-assisted microwave irradiation showed good performance in reducing the viscosity of heavy oil. After microwave treatment for 10 min, the viscosity reduction rate reached 43.61%. In addition, the adsorption of MrGO onto the crude oil droplets could also reduce the viscosity. Compared with conventional water flooding, MGO assisted microwave flooding increased the recovery efficiency by increasing the sweep ratio, as shown in The heterogeneity of the formation makes the injected water directly flow into the oil well along a high permeable layer. The washing action of water to the high permeability layer further aggravates the heterogeneity, which makes it easier for water to break into the oil well along the high permeability layer ,141,142.Profile control and water shutoff are indispensable both in secondary oil recovery  and tertiary oil recovery . The mechanism of profile control and water shutoff to improve oil recovery is to improve the sweep efficiency ,146,147.2/rGO nanocomposite as the crosslinking agent. The novel polymer/graphene nanocomposite had a uniformly distributed three-dimensional network structure. The small size of the gel grid holes made the network structure thermally stable and firmly locked the water in the gel, even at high temperature. The improvement in the properties of this material was mainly due to the high specific surface area provided by graphene at the nanoscale, which increasing the interface interaction between the polymer and graphene. The experimental results of core flooding showed that the pressure drop of sandstone cores with high permeability (Berea sandstone with the permeability of 1000 × 10−3 μm2 and porosity of 21%) increased significantly after treatment. The material had good shear resistance and thermal stability. It can significantly enhance the plugging effect in high-temperature reservoir with lower cost, compared with the existing polymer gel [Almoshin et al. prepared a kind of gel by using low molecular weight polyacrylamide , and ZrOymer gel .Ye et al. found that GO had the function of adjusting the injection volume, plugging the high permeability layer and improving the sweep efficiency, making it can be used as profile control agent in water injection in the oilfield. Flooding experiments in the single core showed that the injection of GO dispersion into the core had two effects, one was to increase the injection pressure of the water phase, the other was to reduce the permeability due to the adsorption and retention of GO. As a result, the mobility of the displacement phase in the core was greatly reduced. Flooding experiments in the two parallel cores showed that in the stage of injecting GO dispersion, it preferentially entered the core with high permeability, and the adsorption of GO in the layer with high permeability caused physical plugging, which increased the injection pressure of high permeability core  have significant quantum confinement effect and boundary effect due to their ultra-small size. They have adjustable band gap and can emit stable fluorescence when stimulated. They are new nano carbon materials with fluorescence properties, in which graphene quantum dots (GQDs) is a special CQDs . MurugesOily wastewater in oilfields refers to all kinds of sewage generated during the process of drilling, production, and transportation, mainly including drilling sewage, wastewater separated from crude oil and other types of oily wastewater ,168,169.Materials with adsorption and separation abilities are often used in oily wastewater treatment ,177,178.6 and 3 × 106 L/(m3·h), respectively [Nguyen et al. prepared graphene nanosheets-based sponges with high oil absorption, good selectivity and recyclability by a dip coating method. The material had super-hydrophobicity and super-lipophilic characteristics, and the adsorption capacity was up to 165 times of its own weight. It was suitable for oil and organic solvent absorption . Also, Qectively .2/GO/rTAc membrane by introducing GO and TiO2 coating into cellulose triacetate (TAC) membrane by electrophoretic deposition. The oil-water separation rate could reach up to 98.9%, exhibiting broad application prospect in oil-water separation [2O3 membrane using GO as the modifier by vacuum transfer method, which has longer service life and better separation performance compared with the unmodified membrane [By adjusting the surface roughness and surface energy, Yang et al. designed a graphene foam material with super hydrophobic characteristics, which had good adsorption properties for both oil and a variety of organic solvents . The enhparation . Hu et amembrane .In the process of oil-gas storage and transportation, crude oil, refined oil and natural gas are all corrosive to equipment and pipelines. With the development of reservoirs with harsh conditions such as high temperature and high salinity, higher requirements are put forward for related metal materials and rubber materials, such as abrasion resistance, corrosion resistance and higher strength ,193.The application of nanotechnology in oil and gas equipment and pipelines is attracting increasing attention in the field of oil and gas industry, especially the application research of nanocomposites. The discovery of carbon nanotubes and graphene with higher strength makes the application of nanocomposites in the field of oil and gas industry become a new hotspot. Nanocomposites refer to the complex system that was prepared based on resin, rubber, ceramic and metal as the continuous phase, and metal, semiconductor, rigid particles and other inorganic particles, fibers, carbon nanotubes and other modifiers as the dispersion phase. The modifier is evenly dispersed in the matrix material by an appropriate preparation method. The equipment and apparatus prepared based on nanocomposite materials have the characteristics of light weight, corrosion resistance, fire resistance, durability and high strength. Nanocomposites can replace some of the metal material components in the oil and gas industry , or as sealing materials , or as coating agent or lubricants ,197,198.Graphene has been widely used in anticorrosive coatings due to its advantages of large specific surface area, good toughness and good self-lubricating property. The graphene-modified coating has a tight structure with improved corrosion resistance and wear resistance. Graphene-modified anticorrosive coatings are a good choice for oil pipe protection ,200,201.During the drilling process, drill bit and downhole power apparatus are the main tools used to break rocks. The harsh environment of high temperature and high pressure put forward higher requirements for drilling tools. Graphene coatings have excellent mechanical properties, which can optimize the surface morphology and characteristics of metal, improve the wear resistance, corrosion resistance and impact resistance of drilling tools, and prevent the tool surface from oxidation and rusting. Chakraborty et al. coated the surface of diamond particles with a graphene film and applied it to PDC  drilling bit, which extended the drilling life, and meanwhile the temperature resistance reached 1200 °C . KeshavaRubber failure is one of the common failures of downhole tools in petroleum engineering. Ocsial company added graphene nanotubes concentrated solution with a mass fraction of 1.7% to nitrile rubber, which increased the tensile modulus of nitrile rubber by about 30%. When the modified nitrile rubber was applied to the rubber stator used in the screw drilling tools, the wear resistance of rubber stator was increased by 20% and the mechanical drilling speed was also increased by more than 20% .Sensors are crucial for finding new oilfields in the process of exploration, safety monitoring in the process of stimulation treatments and data collecting in oil and gas production . In oil 1/2 [In order to ensure the quality of spatial resolution, it is often necessary to use multiple acoustic sensors at the same time in oil exploration. The development of acoustic sensors is directly affected by the development of lightweight diaphragm materials ,214. At 1/2 ,217.The poor conductivity of oil-based drilling fluids could block the direct current, resulting in the unavailability of resistivity logging while drilling. Magnetic graphene nanoribbon stacks (MGNRs) are quasi-one-dimensional graphene-based materials. Their special edge confinement effect makes their properties flexible and adjustable. For example, the magnetic graphene material cannot be used directly because there is no gap between the conduction band and valence band, but it can be applied to the field effect transistor (FET) when it is cut into a smaller scale MGNRs ,219. Gen−1 (45 times higher than that of the silicon piezoresistive pressure sensor) in a wide pressure range (0–50 kPa). The response time under high pressure reached 0.4 ms, which can be promoted in the field of oil and gas exploration [Graphene, as a functional reinforcement material, can enhance the conductivity of composite materials. Compared with other conductive materials, graphene has excellent conductivity, certain degree of flexibility, and good compatibility with organic polymers. It is an ideal material for the preparation of flexible conductive composite materials with organic polymer. Graphene flexible sensors enhance the selectivity of commonly used sensors in oil and gas exploration ,222,223.loration .2 and H2S in natural gas well will gradually exceed the critical value. The corrosion medium will lead to fracture and dropout of rod or tube phenomena, and even cause the scrapping of oil and gas wells. Therefore, the detection of CO2, H2S and other gases is worthy of attention. The graphene-based gas sensor had ultra-high sensitivity and ultra-low detection limit because every atom was able to interact with gas molecule, providing a new choice for oil field gas sensor [There are many types of pipelines used in oil and gas production, and the performance requirements for pipelines are various according to the different construction situations. When the oil field enters the middle or high water cut stage, the properties of produced fluid in oil well has changed, and the partial pressure of the corrosive gas such as COs sensor ,228,229.In the medical field, bones and tissue structures can be distinguished by contrast agents. Similarly, in the field of oil and gas field exploration and development, the fluids and reservoir rock skeletons can also be distinguished by contrast agents, so that the direction of fluid flows can be analyzed and the three-dimensional fracture morphology of the reservoir can be identified. The research of contrast agents based on graphene and its derivatives is one of the hotspots in the biomedical field. Many scholars have shown that the contrast agents based on graphene and its derivatives has good stability, high relaxation rate and easy to monitor and trace. Therefore, contrast agents based on graphene and its derivatives can also be extended to the field of oil and gas industry, expanding their application scope ,231,232.As new materials, the development of graphene and its derivatives needs to go through a gradual process from laboratory discovery to large-scale application, and this should follow the development rules of emerging industries. The application of graphene and its derivatives in the upstream oil and gas industry is still in the initial exploring stage, but with its excellent mechanical, chemical, electrical and optical properties, graphene and its derivatives have broad application prospects in hydrocarbon exploration, oil and water well stimulation, downhole operation, enhanced oil recovery, oilfield wastewater treatment, tools and apparatus, and other aspects. Limited by the cost and the depth of the research, there is still a certain gap between the applications of graphene in the oil and gas industry.In order to promote the application of graphene and its derivatives in the oil and gas industry, further research should be conducted in the following aspects: (1) clarification of the microscopic mechanisms, such as the role of graphene materials in chemical enhanced oil recovery; (2) broadening the research scope in the oil and gas industry, such as the application of graphene materials in shale gas production; (3) revealing the compatibility with other additives, such as the compatibility of graphene materials with surfactant in chemical flooding; (4) putting forward performance requirements for graphene and its derivatives used in the oil and gas industry, such as functional modification of graphene for different purposes in profile control and water shutoff treatments. In addition, how to reduce the cost of industrial application of graphene in the oil and gas industry is particularly important given the current low oil price situation.