Online communities are gaining importance in modern society by actively structuring public opinion and initiating discussions about various socio-economical issues. As information and communication technologies advance, the online communities are confronted with novel technological and societal hurdles . To boost their efficacy and productivity, it’s crucial to enhance our understanding of user behavior, communication avenues and potential future trends of development.Online platforms serve a function beyond simply sharing information or knowledge; they act as influential social networks affecting various societal sectors, including politics, culture and the economy. There is a need to recognize online communities not as static entities, but as dynamic, evolving systems of collective intelligence.A representative quantitative study was carried out between 1 to 30 of October 2022 through direct, in-person interviews conducted at the respondent’s residence (known as an Omnibus survey). The sample of respondents is representative of the entire population of Lithuania regarding essential socio-demographic characteristics. By thoroughly analyzing data gathered from a comprehensive quantitative study, the study raises awareness of the issues surrounding online communities, while also shedding light on social networking behavior within these virtual spaces.Despite the multitude of challenges inherent to virtual communication, there remains a significant knowledge gap in comprehending general user behavior within these online communities. The current research aims to bridge this gap by investigating user behavior in Lithuanian online communities. An online community takes this notion into the digital realm, where it describes a group of individuals united around a common purpose, interest or goal on the Internet. Different researchers have explored this concept through varying lenses. Some focus on the technological interaction between members  while otThe developments of both the digital technologies and how society uses such tools led to significant transformations in how the online communities function. Initially, these platforms primarily served as casual outlets for individuals to share unofficial information, personal concerns, or rumors. Such communities were often seen as secondary spaces to traditional forms of communication and not taken seriously in many instances. Over time, the nature of online communities started changing with the rise of Web 2.0 and social networking sites, enabling more dynamic interactions. As such platforms gained popularity and credibility, governments and corporations began recognizing the potential of online communication. In this regard, online communities have increasingly played pivotal roles in structuring public opinion and instigating discussions about various socio-economic issues . As we vDespite the recognized advantages they offer, online communities face a plethora of challenges that cannot be overlooked. One of the critical criticisms of virtual networks is the limited physical contact between participants, leading to a loss of interpersonal connection that is inherent in face-to-face interactions . FurtherAnother research question is related to deeper understanding of the motivations driving users to participate in online communities. Factors such as enhancing user engagement, improving online safety, increasing information reliability, and promoting respectful communication can be addressed more effectively by comprehending what compels users to interact within these communities. This knowledge can also aid community developers in devising strategies that maximize customer engagement while minimizing potential negative impacts. Many studies have concentrated on the motivations behind individuals’ active participation in online communities . These m2.Lithuania’s online communities offer a unique research platform for studying the potential of networked structures. With a solid foundation of information technology infrastructure, impressive Internet accessibility and a highly-educated population, Lithuania is well-positioned to evolve into an ideal networked society. Lithuania’s long-term plans reinforce this digital readiness, with the 2030 National Progress Strategy emphasizing the importance of a sound information and digital technology infrastructure. Additional strategic measures include the 2020–2030 Lithuanian Industry Digitalisation Roadmap and the National Cybersecurity Strategy for 2018–2023.However, a paradox emerges when considering Lithuania’s civic engagement. Despite high digital access, the annual Lithuanian Civic Empowerment Index  suggestsThe development of Lithuania’s online communities has been influenced by historical factors. The soviet occupation negatively affected non-governmental organizations, stifling civil activity . As resu3.The survey was carried out between 1 to 30 of October 2022. A representative quantitative study was carried out through direct, in-person interviews conducted at the respondent’s residence (known as an Omnibus survey), with the aid of computers . For these computer-facilitated surveys (CAPI), the survey tool – a pre-programmed questionnaire – was used. This software allowed automatic regulation of quotas, logic and typing errors, logical associations between queries, the progression of questions, and their responses. Interviewers ensured that the order of the questions remained consistent throughout. Data were stored directly in a digital format, reducing the potential for human error during data entry. A randomized multi-stage sampling method was employed to select the households and respondents to be included in the survey. The sample of respondents is representative of the entire population of Lithuania regarding essential socio-demographic characteristics . The target group in this study is the Lithuanian population aged 15–74. The household surveys (from which respondents will be selected) are selected in the following steps:Geographic distribution of the sample. Geographically, the sample proportions correspond to the overall population proportions in the different regions. The most recent data from the Statistical Office of the Republic of Lithuania are used;Randomly selecting the initial sampling points, i.e., the addresses from which the sampling route starts, from the Population Register of the Lithuanian Statistical Department database. A total of 117 initial sampling points were used;Households were selected using a route sampling approach. Every second apartment/house in an urban or rural area was visited starting from the initial sampling point. Respondents are selected using the ‘youngest male’ sampling rule.In total, 1,135 respondents were surveyed .3.1.The reliability of survey results depends to a large extent on the way the survey is conducted by the data collectors and on whether all quality control standards for data collection are met. To guarantee the validity and reliability of the gathered data, an independent Quality Control Unit was established. This unit’s role includes overseeing data quality and coding responses to open-ended questions. The data quality check included a check and assessment of compliance with the household selection rules, the respondent selection rules, the quality of the questionnaire, the quality of the route or other respondent record sheet, the general principles of the survey, and the interviewer’s behavior during the survey. Standardized verification techniques were used to check the quality of the data: (1) physical verification of the data series, (2) telephone verification, (3) verification of compliance with the rules of the methodology during the survey, and (4) on-site verification of the conduct of the interview. In addition, the reliability of the questionnaire was tested using test–retest reliability method, which evaluates the consistency of a measure across the time .χ2 test was used to calculate the dependence of one criterion on the other. A relationship was considered statistically significant if the χ2 criterion statistic  is less than or equal to 0.05 (p < =0.05); as a result, it can be said with 95% confidence that the values of the answers to one question are statistically significantly correlated with the values of the answers to the other question. When assessing the results, it will be necessary to pay attention to the statistical bias that arises from the fact that a sample of respondents is selected rather than from a continuous survey. This error is calculated mathematically. The maximum statistical error in the estimation of the responses of all respondents  is due to sampling. It is equal to ±3% at the 95% confidence level, i.e., it will not exceed ±5% at the 95% confidence level.Data analysis was carried out using SPSS/PC software. The All demographic data was collected adhering to the General Data Protection Regulation (GDPR) stipulated by the European Union, and was utilized exclusively for research and statistical purposes. Furthermore, to take part in the survey, all research participants were required to complete a consent form. This was incorporated into the introductory segment of the survey questionnaire, ensuring that participants understood and agreed to the data collection process.4.The questionnaire is based on the following constructs and their scales:I. Internet usage frequency: daily, once a week, several times a week, several times a month, once in three month, not using.frequency of involvement, most frequent online activities, motivation for engagement in online communities, reasons for not participating in online communities.II. Extent of involvement in online communities, motivation, and participation character/ activeness: frequency of involvement, motivation for engagement, areas of interest in online communities focused on societal issues, reasons for not participating.III. Extent of involvement of online communities focusing on social issues and civic initiatives motivation, and participation character/ activeness: level of satisfaction, benefits and disadvantages of online communication.IV. Quality evaluation of different aspects of online communication: The validity of measurement was estimated through expert judgment using on content validity method. Content validity evaluates the extent to which the measurement covers all aspects of the concept measured, and how well an instrument covers all relevant parts of the construct . This me4.1.Approximately 72% of respondents of the survey access the Internet at least weekly, while nearly one-third of Lithuanians between the ages of 15 and 74 either use the Internet less frequently than quarterly or not at all. Daily Internet usage is reported by 53% of respondents. Among Internet users, 63%  frequent various online community websites. Of these Internet users, one-third (35%) visit online communities daily, and a fifth (21%) visit at least once a week. However, over a third of Internet users express no interest in online communities – the majority of them never visit these sites, and 6% have accounts but do not utilize them. Daily participation in online communities is notably higher among Internet users aged between 15 and 29, individuals with primary and secondary education, students, schoolchildren, and single individuals. Those aged between 30 and 39 are more prone to use these sites weekly or less frequently.4.2.Participation in online communities  is exclusively related to the personal interests of the participant, who usually chooses communities groups or forums relevant to his lifestyle, hobbies, and interests . The second most popular topic is communities related to studies/scholarship  see . Pages rThe primary reasons for visiting online communities include maintaining social connections and seeking information on pertinent topics, with 64 and 44% of all responses, respectively. Online communities also serve as platforms for entertainment (28% of responses) and for finding information about products and services (26% of responses). They further facilitate contributions to ideas, initiatives, or projects initiated by others, decision-making processes (like voting for initiatives or selecting charitable causes), and the creation and proposition of new ideas, initiatives, or projects (1–3% of mentions). Single individuals and those living in two-person households are more inclined to participate in online communities to sustain social connections and to remain in contact with acquaintances. Residents of the three largest cities show a higher likelihood of utilizing these platforms to seek information on matters of concern  of all Internet users frequent online community websites centerd around public issues. Users who have one child in their household and those who participate in online community activities daily are statistically more likely to use websites focusing on societal matters. Based on the findings, online communities offer participants pertinent information, intriguing articles, commentary, and overall, expand their worldviews. Nearly half of the visitors to these sites also take the opportunity to express their viewpoints. Married and cohabitating individuals are significantly more likely to contribute to initiated projects by suggesting possible improvements and applying their knowledge to identify and solve various social issues. On the other hand, single individuals tend to seek like-minded people. Women show a higher likelihood of seeking relevant information, and those with one child in their household are more inclined towards reading articles and comments  express concerns over participating in virtual activities aimed at social problem-solving due to perceived dangers – such as fear of being accused of ulterior motives, threats, harassment, potential physical harm, or job loss. However, respondents underlined the importance of state oversight of Internet content and called for increased focus on data security and intellectual property protection. Single women are more likely to abstain from participation due to a perceived lack of appeal. Those claiming a lack of time are more likely to be aged 50–59 and to have two or more children  concur that online communities should bear strict liability for any infringements of others’ rights. They also believe that site administrators should be held accountable for disseminated content, that these administrators should scrutinize the information they share, and that virtual community activities should fall under detailed legal regulation. Most Internet users acknowledge the issue of identity theft in the virtual world, such as the creation of fraudulent profiles or blogs impersonating renowned individuals. They also agree that there is a greater prevalence of intolerance and defamation online than in real life.5.The vast majority of surveyed Internet users (63%) frequent these online communities, making them an ideal platform for civic engagement and interaction. The study also reveals that the level of participation in these communities is determined largely by personal interests. Online communities centerd around hobbies, lifestyle, and personal interests attract the highest levels of active participation. This active participation extends beyond passive engagement, with members actively contributing to content creation, discussion, and experience sharing. It suggests that online communities can be more effectively leveraged for civic participation by aligning them with people’s interests, thereby encouraging greater active involvement. The findings also indicate that there is a high level of engagement in communities focusing on academic or scholarly topics. This suggests an interest in learning and knowledge-sharing within the Lithuanian online community space. The research findings align with existing literature that sees online communities as a form of civic participation, bridging the gap between individual interests and broader societal issues . ZarifisHowever, it is also evident that participation in online communities oriented towards societal issues is limited, with only 18% of surveyed internet users, or 12% of the total population, engaging with such communities. This limited engagement in social or societal matters beyond personal interests presents a significant challenge to leveraging the potential of online communities as platforms for civic participation. While these platforms can facilitate connections and conversations on broader societal issues, their effectiveness is contingent on active and diverse participation. The results suggest that these communities must do more to attract and engage users if they are to realize their full potential as forums for civic engagement. Interestingly, daily online users and those with children in their households are the most likely to visit these socially-focused online communities. This suggests that these demographics may be more inclined towards societal engagement, potentially due to their daily interaction with digital platforms or their interest in societal issues impacting their children’s futures. Despite the limited participation, those who do engage with online communities centerd on societal issues find value in the information, engaging content and diverse commentary offered. These platforms serve to broaden their perspectives and almost half of the visitors take the opportunity to voice their opinions. The topics of highest interest include ecology, environmental challenges, climate change, education and social welfare. These results are in alignment with the study of Concerns over cybersecurity, including threats to personal data, intellectual property, and potential violations of rights and obligations, act as barriers to participation. These findings emphasize the need for online communities to prioritize the establishment of secure environments. Users need to feel safe when participating, contributing, and generating ideas that could benefit society at large. This is an area of concern in wider online community research as well. Issues surrounding data privacy and personal security have been identified as significant factors influencing individuals’ willingness to participate in online communities . The finFinally, results show that the platform creators should bear in mind the importance of simplicity and user-friendliness when devising technological solutions. Users of these websites express a longing for a genuine impact on socio-political issues, a valid representation for society, clarity and structure in topics, quality discourse, the freedom to voice their opinions, and user-friendly technological solutions. Interestingly, such views are prevalent across various socio-demographic user groups. One inference that can be drawn is that the advantages of virtual activities, such as openness, adaptability, and accessibility, may inadvertently contribute to additional psychological challenges for participants. The desire for user-friendly and straightforward technological solutions expressed by the users echoes the consensus in the wider research sphere that emphasizes the importance of usability in technology design. Numerous studies have found that simple, intuitive user interfaces enhance engagement and contribute to the overall success of online communities .6.This study contributes significantly to research on online communities by providing insights into how such communities function within Lithuania and how they may evolve elsewhere. It expands our understanding of participation dynamics, demonstrating that personal interest is a key driver of active involvement. In this regard, the data indicate that online communities in Lithuania are becoming an increasingly significant channel for societal participation. They offer a more relatable and modern approach to decision-making processes and involvement in societal issues, reflecting the evolving lifestyle and communication preferences of contemporary society.The study provides a comprehensive examination of participation dynamics within the unique context of online communities in Lithuania. It importantly highlights that personal interest serves as the central driver for active engagement, with communities focused on hobbies, lifestyle, and personal interests eliciting the highest levels of participation. Interestingly, despite the extensive adoption of online communities—observed in 63% of the surveyed Internet users—engagement in platforms focused on societal issues is limited, indicating a challenge that needs to be addressed to realize the full potential of these platforms as venues for civic participation in post-soviet countries. The study further illuminates concerns over cybersecurity, emphasizing the importance of secure environments in fostering participation and the generation of ideas for societal benefit.The originality of the paper is national socio-cultural context of one country. However, this is also one of the limitations of this research and the reason, why the conclusions can not be generalized or applied to other countries without additional research. Another limitation is that this study relies on the answers of individual users without considering the interaction between participants. Future studies could analyze participants’ communication and interaction habits or behavioral changes over time. Results are based on a limited dataset in Lithuania. Therefore, findings can only be generalized to online communities in Lithuania. Looking forward, there are several key areas that future research can delve into. The first is the exploration of strategies to increase user engagement in online communities concentrating on societal matters. This could involve identifying and overcoming barriers to participation. Secondly, there is a need for an in-depth understanding of users’ cybersecurity concerns and an investigation into the impact of various security measures on their willingness to engage. Lastly, it would be of interest to examine the potential psychological challenges posed by participation in online communities and how these can be mitigated. For practitioners, particularly those designing online communities, several key implications arise from the findings of this study. Firstly, there’s an identified need to align community themes with potential users’ personal interests as a strategy for encouraging participation. Secondly, designers must prioritize establishing robust cybersecurity measures to build trust and create a safe environment for users. Lastly, the study underscores the importance of usability in online community design. Users expressed a strong preference for simplicity and user-friendliness in their platforms—an aspect that should not be overlooked in the design process. Taken together, the insights from this study contribute significantly to our understanding of online communities, pointing to critical areas of focus for designers and researchers alike.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.Ethical review and approval was not required for the study on human participants in accordance with the local legislation and institutional requirements. Written informed consent from the patients/participants or patients/participants legal guardian/next of kin was not required to participate in this study in accordance with the national legislation and the institutional requirements.AS: Conceptualization, Methodology, Writing – original draft. MM: Conceptualization, Methodology, Writing – review & editing.


We present a simple and cost-effective fabrication technique for on-chip integration of pure edge contact two-terminal (2T) and Graphene field effect transistor (GFET) devices with low contact resistance and nonlinear characteristics based on single-layer chemical-vapor-deposited (CVD) graphene. We use a smart print-based mask projection technique with a 10X magnification objective lens for maskless lithography followed by thermal evaporation of the contact material Cr-Pd-Au through three different angles (90° and ± 45°) using a customized inclined-angle sample-holder to control the angle during normal incidence evaporation for edge-contact to graphene. Our fabrication technique, graphene quality, and contact geometry enable pure metal contact to 2D single-layer graphene allowing electron transport through the 1D atomic edge of graphene. Our devices show some signatures of edge contact to graphene in terms of very low contact resistance of 23.5 Ω, the sheet resistance of 11.5 Ω, and sharp nonlinear voltage-current characteristics (VCC) which are highly sensitive to the bias voltage. This study may find application in future graphene-integrated chip-scale passive or active low-power electronic devices. Many researchers and industry are hopeful about the integration of graphene into silicon technology towards technological revolutions in active and passive micro and nanoelectronic devices. However, the metal-to-graphene contact resistance is a key parameter when considering the CMOS compatibility of graphene7. The contact resistance’s nature depends on the physical interaction between the metal and the atomically thin graphene for the injection of charge carriers into the channel region8. An electrostatic field is created when the metal comes in contact with the graphene atoms and prohibits the further transfer of carriers in the graphene channel. The more, the electrostatic field at the junction, the higher the applied field required to transport carriers inside the channel and vice-versa. Therefore, it is important to reduce the electrostatic field near the metal-graphene junction either through physical changes to the geometry at the metal-graphene interface or through chemical treatments to graphene or contact metals10. Contact resistance also plays a role to tune the charge neutrality point in multi-layer graphene for several applications11.Graphene is considered a suitable 2D material for optical, electronic, and optoelectronic applications due to its superior physical properties such as lightweight, charge carrier mobility, large surface area, high electrical and thermal conductivity, zero and tunable bandgap and optical transparency14, choice of contact material15, doping to graphene10, contact-pad patterning10, chemical and thermal treatments to graphene15, UV treatments to graphene16 and edge contact to graphene20. So far, edge contact to graphene is the most successful technique to improve the M-G contact resistance. It can be done either through chemically doping the graphene, UV exposure to modify the chemical bonds in the graphene, or through physical contact geometry to graphene, which also indirectly dopes the graphene. Moreover, from a device robustness and performance reproducibility point of view, a contact geometry-based edge contact is comparatively more effective. Recently, Park et al.10 have presented an edge-top contact design including patterned TLMs below the graphene contact electrode that shows reduced contact resistances which can also be extremely reduced through a combination of edge contact and n-type doping to graphene. A similar study is carried out by Song et al.18 by patterning the contact electrode to graphene for improved edge contact. However, these multi-step techniques allow chemical doping to the graphene edge and are partially edge-contacted.There are wide studies reported in this direction for the reduction of metal-graphene contact resistance through the active region or contact geometry17 through asymmetric Ni–Au and Ti–Au contacts to graphene, which is highly nonlinear, whereas it shows a total resistance of 74 KΩ between contacts to the graphene. Wang et al.13 have presented 1D edge contact to exfoliated 2D graphene sandwiched between two layers of boron nitride (BN) and show low contact resistances of the order of 100 Ω at low temperatures. Further, most of the devices with low contact resistances are based either on exfoliated graphene or epitaxial graphene22. Here, in our study, (1) we can grow and transfer single-layer graphene using CVD, (2) integrate it to two-terminal devices using a cost-effective and simple fabrication approach as described below. (3) As the signature of a pure 1D edge-contact geometry, we have achieved much-improved contact resistances at room temperature compared to those presented in the literature21, nonlinear total resistance variation concerning graphene channel length and a voltage-sensitive nonlinear voltage-current characteristic reflecting the nature of charge carrier transport from metal contacts through 1D atomic-edges of single layer-graphene. (4) Next, we have also verified the nonlinear resistance variation in our devices through the fabrication of edge-contacted TLM sets with variable graphene channel length and width. There are wide studies reported on the transport properties and VCC of graphene using field effect devices under several conditions such as channel length scalability, doping to contact electrode, and top gate interface-trap engineering through top-gate, etc.25. Therefore, (5) to understand the edge-contact effects on transport properties and the Dirac point of graphene, and the edge-enhanced nonlinearities in VCC, we have included a separate study on the edge-contact graphene field effect transistor (GFET) device. Initially, we fabricated an edge-contacted 2 T device with a graphene channel width of 200 µm and a channel length of 30 µm using the same technique, and then we added a top gate insulated by 120 nm of Parylene N.There are limited studies reported on pure edge contact devices to CVD graphene for improvement of metal–graphene contact resistance. A pure 1D edge contact device is presented by Hemmetter et al.2 through Cr–Pd–Au contact to pure plasma etched 1D edge-of the graphene. These devices may find application in future graphene-integrated low-power electronic devices and fast-charging electrodes.Our devices show a contact resistance of 23.5 Ω leading to 0.117 Ω per µm (4.7 K Ω µm) and a contact resistivity of 1.4 Ω µm26. The microscope image of the device with a graphene channel length of 3 µm, and channel width of 200 µm is shown in Fig. The one-dimensional schematic of the Cr-Pd-Au edge contact device is presented in Fig. 2 from the patch region towards the non-patch region is presented in Fig. 2D/ IG+ of 4.2 and I2D/ IG− of 5.92. Due to the stretching of the Graphene plane during PET transfer, a splitted G peak appears with G− at 1574 cm−1 and a blue-shifted G+ peak at 1608 cm−1. We have a negligible D peak at 1345 cm−1, and the 2D peak is at 2630 cm−1. Rests of the peaks are due to the PET substrate. A 2D plot of the Raman map is presented in the supplementary material  and the SMU2. The VI characteristics of the sample are presented in Fig. 13 at low temperature (1.2 K) for FET devices based on 1D edge-contact to exfoliated graphene. This kind of nonlinear VCC and resistance variation is a sign of pure 1D edge contact in a short graphene channel length (2 μm) 2 T device. Here, the transport near the contact is dominated showing a clouding effect of charge carriers due to the electrostatic field near the metal–graphene interface for zero and low biasing voltages is evidenced, which is overcome with increasing bias voltage allowing a continuous flow of current in the graphene channel. It is believed that the electrostatic effect arises at metal–graphene contact due to doping to graphene either due to two different chemical potentials of contact material and the graphene or contamination/ oxidation of contact metal during processing leading to a potential barrier, which is quite small to be overcome with the supplied voltage. The pure-edge contacted device allows us to observe this phenomenon through nonlinear VCC and the Keithley system is highly sensitive to detect it.As observed from Fig. Figure 13. Where RC is the contact resistance, C) is obtained from the Y-intercept of the channel length vs. total resistance plot in Fig. C × L = 47 Ω µm (minimum) and RC × W = 4.7 K Ω µm (maximum).Next, we fabricated three devices with variable graphene channel lengths , integrated them into a single chip for a constant width of 200 µm, and characterized them with the Keithley measurement system at room temperature. The total resistance as a function of the biasing voltage for variable channel lengths is presented in Fig. To verify and bring clarity to the nonlinear variation of the total resistance concerning the channel lengths in the edge-contact devices, we have fabricated edge-contacted TLM devices following the same fabrication technique with Cr–Pd–Au contacts to graphene. The TLM devices with variable channel lengths 10–60 µm) and channel widths of 50 and 200 µm have carried out a similar study  × graphene channel width × width of graphene = 23.5 Ω × 200 µm × 0.0003 µm = 1.4 Ω µm2. It was believed that the device can show even much lower contact resistance than those reported in the literature for smaller channel widths of the devices. However, we have tried to reduce the graphene channel width to 40, 20, and 10 µm and fabricated a few devices. We observed that the contact resistance varies inversely as a function of the width of the graphene channel. This is also valid because higher channel width reduces the contact resistance through the inclusion of more resistances in parallel contributing to the contact resistance as shown in Fig. 26.As we have contact with the graphene only at the edge, we calculate the contact resistivity as presented in28. The quiet mode-scanning of the Keithley system with pre-amplifier connected SMU1 is highly sensitive to detect these edge-enhanced quantum effects at the metal–graphene edge. The nonlinearity in edge-contacted devices is also a phenomenon as presented in Hemmetter et al.17, which is highly prominent in large–contact resistance devices.Further, we have also studied the VI characteristics of the edge contact devices integrated into a single chip with channel lengths 5 and 20 µm using SMU1 and SMU2 of the Keithley parameter analyzer, and the results for L = 5 are presented in Fig. As we increase the voltage from ± 10 to ± 100 mV, we see a similar VCC in Fig. To further understand the origin of edge-enhanced nonlinear effects in edge-contacted devices we have fabricated edge-contacted graphene field effect transistors (GFET) and the study on current–voltage and charge transfer characteristics are presented in Fig. DS) vs. drain-source current (IDS) plot which is almost linear except for two sharp nonlinear peaks/dips near the zero biasing voltage. The origin of these two nonlinear responses in the VCC at low voltages is due to the dominant edge contact effects as discussed before. This can also be understood from the aspect of edge-contacted graphene FETs showing somewhat nonlinear-response-like semiconductors such as dark current in the absence of voltage as reported by Lee et al.29. Further, as we supply and increase the gate voltage from 1 to 5 V, it is observed that two peaks/dips in the VCC merge to a single nonlinear dip and shallows due to the continuous flow of current in the GFET as shown in Fig. 23. Figure GS vs ID at VD = 0.5 V) of the edge-contacted FET with VDirac shift to negative voltage showing an n-type graphene channel of the device with Cr–Pd. Au (1–15–100 nm) contacts to graphene, where Pd–Au provides n-type doping to the graphene channel. The nonlinear GFET also shows an asymmetric transfer characteristic as evidenced by Fig. Figure 2 chips are glued to the Cu-Graphene substrate through epoxy Epotek 353ND (1:10) and dried at 60 °C for a few hours. Cu is etched in 30% HNO3 for a few minutes and graphene is transferred to Si–SiO2 as shown in Fig. 30. We have fabricated the contact to graphene in a two-step and cost-effective maskless photolithographic process using Microlight 3D smart print. Initially, we have patterned the contact pads through the maskless lithography using a three-layer resist coating including S1805, LOR 3A, and S1813 as shown in Fig. 2 under a pressure of 250 mBar. However, the undercut prohibits contact metal to touch the graphene edge under normal incidence thermal evaporation. After many failures to achieve edge contact with graphene through normal incidence evaporation on the plasma etched metal contacts, we deal with this challenge through a customized sample holder which allows us to rotate the sample plane up to ± 45°. Further, we have also chosen Cr–Pd–Au (1/7.5/50 nm) as the contact metal to graphene, which is proved to be a suitable choice of contact material for graphene to achieve high mobility31. Cr–Pd–Au is deposited on the sample from three different angles  to reach the edge of the graphene from all directions as shown in Fig. 2 plasma etching. Now, the device as shown in Fig. Graphene is grown on a 2-inch copper (Cu) foil using CVD as per the procedure presented in the supplementary material. The Si–SiOIn the presented study, we could achieve pure metal contact to the 1D edge of single-layer 2D graphene through a cost-effective and simple fabrication approach and have studied the voltage-current characteristics of the integrated graphene to two-terminal (2 T), TLM and FET devices. The Cr–Pd–Au edge contacted 2 T device shows a contact resistance of 23.5 Ω between the two terminals, a nonlinear total resistance variation concerning voltage and channel lengths, a nonlinear voltage-current relationship that is highly sensitive to the input voltages, and shows some signs of charge clouding and quantum transport effects through atomic edge-of graphene. Nonlinear VCC in graphene devices is applicable in frequency mixing and switching. This study presents a robust approach toward realizing geometry-dependent graphene-integrated edge contact devices with low contact resistance for future high-speed and low-power graphene-integrated electronic devices and circuits.Supplementary Information 1.Supplementary Table S1.


Respiratory viral infections (RVIs) are major drivers of chronic obstructive pulmonary disease (COPD) exacerbations. Interferon beta (IFN-β) is key in host defence against viruses but can be suppressed by virus or host factors locally at the site of infection. Inhalation of SNG001 (IFN-β-1a nebuliser solution) aims to restore lung IFN-β levels. SG015 (NCT03570359) was a randomized, placebo-controlled Phase 2 clinical study of inhaled SNG001 conducted in COPD patients. Here we describe lung antiviral biomarker and sputum viral clearance data from Part 2 of the study which was conducted in patients with a confirmed RVI.109 COPD patients with worsening symptoms and a positive respiratory viral test were randomized 1:1 to SNG001 or placebo once-daily for 14 days in two Groups: A (no moderate exacerbation); B . Sputum samples were collected on days 1, 4, 7, 10, 13, 17 and 28 for analysis of lung antiviral biomarker responses (interferon-stimulated genes (ISGs): Mx1, OAS1 and CXCL10) and lung viral load by RT-qPCR.post-hoc analysis was therefore conducted in the subgroup of patients who had detectable rhinovirus viral load in sputum. By Day 4 the proportion of patients receiving SNG001 who had detectable rhinovirus reduced to 40.0% , with a further reduction to 20.0% on Day 7 .Mx1 and OAS1 sputum cell gene expression were significantly upregulated on day 7, 10 and 13 (p< 0.05) overall and in Groups A and B with SNG001 treatment compared to placebo. CXCL10 sputum cell gene expression was significantly upregulated in the overall population with SNG001 treatment compared to placebo on days 7 and 10, in Group B on days 7, 10 and 13, and there was no significant difference in Group A. Patients had a broad range of RVIs, the most common being human rhinovirus. A Inhaled SNG001 upregulated lung antiviral defenses as assessed using sputum cell biomarker responses and accelerated viral clearance, supporting the proposed mechanism of action as an antiviral treatment for severe viral lung infections.Phillip D. Monk, PhD, Synairgen Research Plc: Employee of Synairgen Research Plc and has options on shares|Synairgen Research Plc: Stocks/Bonds Jody L. Brookes, BSc, Synairgen Research Ltd: Share options Victoria J. Tear, PhD, Synairgen Research Ltd.: Stocks/Bonds Marcin Mankowski, MD MFPM (Dis), Multiple companies: Advisor/Consultant|Synairgen: Advisor/Consultant Michael G. Crooks, MBChB (hons), MD, FRCP, AstraZeneca: Advisor/Consultant|AstraZeneca: Grant/Research Support|AstraZeneca: Honoraria|Chiesi: Advisor/Consultant|Chiesi: Honoraria|Gilead: Honoraria|Synairgen: Advisor/Consultant Dave Singh, MD, AstraZeneca: Advisor/Consultant|Chiesi: Advisor/Consultant|gsk: Advisor/Consultant|Novartis: Advisor/Consultant|Orion: Advisor/Consultant|Pulmatrix: Advisor/Consultant|Sanofi: Advisor/Consultant|Synairgen: Advisor/Consultant|Synairgen: Grant/Research Support|Therevance: Advisor/Consultant Rekha Chaudhuri, MD, AstraZeneca: Grant/Research Support|AstraZeneca: Honoraria|Chiesi: Honoraria|GSK: Honoraria|Novartis: Honoraria|Sanofi: Honoraria|Teva: Honoraria Sarah Dudley, N/A, PhD, Synairgen Plc: Employed by Synairgen Research Ltd which is a subsidiary of Synairgen Plc|Synairgen Plc: Stocks/Bonds Felicity Gabbay, MbChb, Synairgen: Board Member Stephen T. Holgate, FMedSci, MD, Synairgen Research Plc: Board Member|Synairgen Research Plc: Stocks/Bonds Ratko Djukanovic, MD, GlaxoSmithKline: Advisor/Consultant|GlaxoSmithKline: Honoraria|KyMab: Advisor/Consultant|Sanofi: Advisor/Consultant|Synairgen: Advisor/Consultant|Synairgen: Stocks/Bonds Tom Wilkinson, PhD, PhD, Synairgen: Advisor/Consultant|Synairgen: Grant/Research Support|Synairgen: Honoraria


Diamanes are unique 2D carbon materials that can be obtained by the adsorption of light atoms or molecular groups onto the surfaces of bilayer graphene. Modification of the parent bilayers, such as through twisting of the layers and the substitution of one of the layers with BN, leads to drastic changes in the structure and properties of diamane-like materials. Here, we present the results of the DFT modelling of new stable diamane-like films based on twisted Moiré G/BN bilayers. The set of angles at which this structure becomes commensurate was found. We used two commensurate structures with twisted angles of θ = 10.9° and θ = 25.3° with the smallest period as the base for the formation of the diamane-like material. Previous theoretical investigations did not take into account the incommensurability of graphene and boron nitride monolayers when considering diamane-like films. The double-sided hydrogenation or fluorination of Moiré G/BN bilayers and the following interlayer covalent bonding led to the opening of a gap up to 3.1 eV, which was lower than the corresponding values of h-BN and c-BN. The considered G/BN diamane-like films offer great potential in the future for a variety of engineering applications. It was proposed in 2009  as a hydoperties ,2,3,4. Doperties . The synoperties ,7. The foperties  and fluooperties , one-sidoperties  and moleoperties  or covaloperties ,14.Diamane-like materials can not only be obtained on a base of AA- and AB-stacked bilayer graphene ,16; twisThe manipulation of the properties of vertically stacked two-dimensional materials by a twisted angle was named “twistronics” . The twix substrate induced by high pressure were investigated. Pressure-dependent charge injection experiments on graphene/BN heterostructures have shown that the efficiency of the charge injection decreases with increasing pressure, which indicates a conductor–insulator electronic modification. DFT calculations of twisted graphene/BN with passivation by OH groups from the graphene side, formed using water as the pressure medium, have shown a bandgap opening, which is in agreement with experimental results. These calculations were performed for twisted layers without taking into account the difference in the lattice parameters of graphene and BN.One of the parent layers of diamanes can be replaced with a structural analogue of graphene, namely hexagonal boron nitride h-BN. Diamane-like materials based on untwisted G/BN bilayers have been widely investigated theoretically in recent years ,27. In tIn the synthesis of diamane-like G/BN structures, it is impossible to obtain a material with an AB diamane structure due to the incommensurability of the layers. Here, we present the results of DFT calculations of a new diamane-like material based on a Moiré G/BN bilayer fully passivated by hydrogen and fluorine atoms, taking into account the lattice mismatch.−5 eV. The atomic structure minimization was carried out until the change in the total energy was less than 10−3 eV.The geometric optimization and the calculations of the electronic properties of the considered Moiré G/BN structures were performed by the density functional theory (DFT) method implemented in the VASP package ,30,31. WG/aBN, and common values of δ range between 0.014 and 0.021, corresponding to lattice parameters of aG = 2.46 Å, aBN = 2.49 Å and aG = 2.46 Å, aBN = 2.51 Å, respectively [56B27N27 and C74B36N36 and a mismatch of δ10.9 = −0.0017 and δ25.3 = 0.0028, respectively. The mismatch of these supercells was five- to twelve-times smaller than the mismatch of the G and BN cells. Thus, the layers of these twisted supercells were less compressed or stretched and should be energetically more stable in comparison with untwisted structures [Graphene and h-BN monolayers are structural analogues and have the same hexagonal lattice. The differences lie in their atomic composition and lattice parameters. When the layers are put onto each other, a mismatch leads to the formation of the Moiré pattern. The lattice mismatch is determined by the formula δ = 1 − aectively . The twoectively . The supectively . Our DFTructures . The G/BThese hybrid bilayers provided the basis for the diamane-like structures discussed below. Only the structures with their rotation center situated in the middle of the C-atomic hexagon in the carbon layer and coinciding with the center of the atomic BN hexagon of the other layer were considered.The formation of diamane-like materials is a two-stage process. The adsorption of atoms or molecules onto the outer surfaces of few-layered materials leads to a curvature of layers and changes their hybridization. The inner surfaces become chemically active, which leads to the formation of interlayer bonds. This mechanism has been predicted for untwisted few-layer graphenes ,38 and fHydrogen and fluorine atoms are considered as adsorbent. Hydrogens obtained during the hot-filament process were used in the synthesis of diamanes by the Piazza group . In addi3 hybrid G/BN bilayers with θ = 25.3° had C–C and B–N bond “crossings”, and the atoms of these bonds did not combine during the process of the formation of the diamane-like material. Not all bond “crossings” are perfect. “Crossings” with a shift of one of the bonds, to which hydrogen adsorption is also preferable, were located in the intermediate regions 74 and C56B27N27H(F)46 supercells, respectively. Fewer atoms in the BN layer prevents the formation of the same number of interlayer bonds as in carbon diamanes. Therefore, a sufficiently large amount of adsorbed atoms was chosen compared to non-twisted and twisted carbon diamanes [3 structure.In this paper, we considered several possible schemes of fully spStructural heterogeneity leads to the formation of non-equivalent interlayer bonds in contrast to untwisted G/BN bilayers , which of = (Etot − NCEG − NBNEBN − NH2(F2)EH2(F2))/N, where Etot is the total energy of the G/BN diamane-like structure, NC ) and EG) are the number of carbon atoms (boron + nitrogen and adsorbed atoms) and the energy of the atoms in graphene , respectively, and N is the total number of atoms in the calculated cell. The fluorinated structures were more stable than the hydrogenated ones. The negative formation energies demonstrated the higher possibility of their synthesis. The hydrogenated structures had positive energies and could be synthesized at a high external pressure and/or temperature.The formation energies were calculated using the formula: E1 and AB2 stacking, where there are only C-B and C-N interlayer bonds, respectively. Untwisted three-layered hybrid C/BN heterostructures are also stable [The conclusions about the dynamic stability of the considered G/BN diamane-like films was made on the basis of already-published works. The stability of fully carbon diamanes based on hydrogenated/fluorinated AA- and AB-stacked bilayer graphenes was predicted  and confo stable . It is io stable . The info stable  and hydro stable  diamanesStructural transformations of a G/BN bilayer change its properties. Graphene is a semimetal that has a conduction and a valence band that meet at the Dirac point. Hexagonal boron nitride has a wide bandgap of >6 eV. Dirac cones of graphene are well preserved in combinations of twisted graphene and h-BN . The intThe adsorption of atoms onto graphene and BN distorts their flat surfaces, where atoms leave the plane and bind to hydrogen or fluorine atoms e,f. The g values of 2.5 and 3.0 eV corresponded to the fluorinated G/BNs. The twisted heterobilayers had mixed C-N and C-B interlayer bonds in the structure in contrast to the AB-G/BN, where the interlayer bonds were of the same type. Therefore, the difference between the Eg of fluorinated twisted structures of 0.5 eV was lower than the 1.3 eV obtained for fluorinated AA-G/BN heterobilayers [The G/BN structures with θ = 25.3° are semiconductors with a direct bandgap in the Γ-point. The hydrogenated ones had a bandgap of 2.7 and 3.1 eV with C-B and C-N bonds in the AA-stacked area, respectively a,b. The bilayers . The G/Bbilayers ,45.56B27N27H(F)43 had almost flat bands crossing the Fermi level  is the density of the adsorbed atoms on the surfaces. The lower density of H(F) makes it impossible to for it to cover all the carbon, boron and nitrogen atoms not involved in the formation of the interlayer bonds. The presence of these sp2-hybridizated carbon, boron and nitride species leads to electron localizations and band flattening. Similar hybrid sp2/sp3 structures based on fluorinated/hydrogenated graphene bilayers with diamane-like domains were investigated earlier [To estimate the effect of the quantity of adsorbed atoms on the electronic structure, hybrid G/BN structures with θ = 10.9° and a reduced number of H(F) atoms were calculated. The removal of two atoms on the BN side and one on the graphene side led to a significant change in the properties. The defected G/BN structures Cmi level . These mgraphene . The rea earlier .The presence of a Moiré periodic superlattice makes the appearance of flattened zones in the transformed electronic spectrum of graphene in such hybrid structures possible. Moreover, two factors act on its change, namely the covalent bonding of the carbon atoms with the boron and nitrogen atoms, leading to the appearance of wide band gaps in the spectrum, as well as the interaction of the carbon atoms with the inhomogeneously adsorbed hydrogen atoms, leading to the appearance of a narrow miniband, which is similar for the case of a system with hydrogen adsorbed on a diamond surface , in part2 as bilayer graphene [We believe that double-sided passivated G/BN heterobilayers can be produced by the existing methods. Graphene layers can be grown quite precisely on the surface of boron nitride  or rotatgraphene . Double-graphene . The covgraphene . Thus, tDiamane-like films have great potential for application ,55. The 3 hybrid diamane-like structure. The total energy calculations showed the higher stability of the fluorinated structures compared to the hydrogenated ones. Destroying the π-system of graphene led to the bandgap opening up to 3.1 eV. However, the electronic properties of these hybrid diamane-like structures are sensitive to the density and type of the adsorbed atoms, the interlayer connections and the twisting angle of the parent bilayer. A slight decrease in the number of adsorbed atoms led to the appearance of very narrow metal minizones, which were associated with the presence of sp2 atoms. The choice of the twisted angle and the density of adsorbed atoms can be used for the precise tuning of the electronic properties of the obtained films. These results indicated that diamane-like hybrid materials could be interesting for applications in next-generation devices.In summary, a new diamane-like material based on twisted G/BN bilayers was proposed. DFT calculations were performed on the examples of diamane-like films based on parent bilayers with twisted angles of θ = 10.9° and θ = 25.3°. These angles were determined from the obtained dependence on the number of atoms on the twisted angle for bilayers with a lattice mismatch of δ < 1%. The hydrogenation or fluorination of the bilayer surfaces led to interlayer covalent bonding and the formation of a fully sp


The development of new scaffolds and materials for tissue engineering is a wide and open realm of material science. Among solutions, the use of biopolymers represents a particularly interesting area of study due to their great chemical complexity that enables creation of specific molecular architectures. However, biopolymers do not exhibit the properties required for direct application in tissue repair—such as mechanical and electrical properties—but they do show very attractive chemical functionalities which are difficult to produce through in vitro synthesis. The combination of biopolymers with nanostructured carbon fillers could represent a robust solution to enhance composite properties, producing composites with new and unique features, particularly relating to electronic conduction. In this paper, we provide a review of the field of carbonaceous nanostructure-containing biopolymer composites, limiting our investigation to tissue-engineering applications, and providing a complete overview of the recent and most outstanding achievements. Complex chemical architectures represent a challenge for material science and synthetic chemistry. Several approaches can be used to achieve the complexity that naturally occurs in living organisms during anabolic metabolism. The level of complexity shown by biopolymers is astonishing and represents an opportunity to apply ready-to- use complex building blocks for the production of new materials . This isTissue engineering is one of the most cutting-edge applications of polymer science, aiming to repair and replace damaged biological tissues using polymers and polymer composites by means of several production routes, as illustrated in Over the last two decades, the realm of tissue engineering underwent rapid developments and several experimental routes for the reparation and regeneration of organs, tissues and cells were developed . FurtherThe great advantage of biopolymers compared with synthetic polymers is associated with the complexity of their molecular architectures and their reproducibility resulting from biological pathways. The great potential for the application of biologically synthesized polymers, together with the role of purification procedures, is evidenced by considering cellulose as a case study. The structure of cellulose was determined by Staudinger in the early years of the 20th century . Even noNevertheless, several biological applications—ranging from scaffolding to prosthetics—require superior conductive and mechanical properties. Neat biopolymers do not perform well enough to be used without mixing them with fillers. Nanostructured fillers, such as graphene derivatives  and CNTsGraphene, graphene oxide (GO) and reduced GO (rGO) are briefly illustrated in 2 hybridization, while the p orbitals perpendicular to the sp2 plane do not participate in the bonding, hosting the conduction electrons. As a consequence, the electrons in the 2 V−1 s−1, room-temperature ballistic transport and half-integer quantum Hall effects [In its ideal form, graphene is a two-dimensional crystal of carbon atoms bound in a honeycomb lattice and can be thought as a single plane of graphite. In each elementary cell of graphene, each carbon atom is linked by three in-plane ne plane ,30,31, ene plane . The pec effects . These f effects .The astonishing properties exhibited by ideal graphene are counterbalanced by its poor compatibility with established technological pipelines, as well as its scarce availability . Indeed,Due to this sensitivity to the production path, several structures have been proposed for GO in different studies, such as the Hofmann, Ruess, Scholz–Boehm, Nakajima–Matsuo, Lerf–Klinowski, and Szabo models ,40.Among these, the Lerf–Klinowski model is usually considered to represent the most realistic description of actual GO , attribuGO is not the only graphene-derived material currently under extensive scientific investigation. Another very promising graphene-based material is reduced graphene oxide (rGO), which is obtained through a reduction process of GO by means of several reducing agents . This prDespite their astonishing properties, graphene-related materials can damage cellular structures, promoting oxidative degradation, apoptosis and cell-membrane disruption , mainly The use of graphene and related materials for biological applications can exploit several interesting features ,48. The As reported by Bahrami et al. , graphen2-hybridized carbon atoms and can be thought of as cylindrical graphite sheets rolled up in a tubular structure. Different types of folding are possible for CNTs according to the so-called chiral vector n and m are the positive integer chiral indexes, and q is a positive integer) the CNT is metallic, otherwise it is semiconducting. Armchair CNTs always show metallic behavior, whereas chiral CNTs exhibit the same geometric properties as enantiomeric molecules.CNTs are another carbon allotrope based on the honeycomb lattice of spnducting ; specifi2-hybridized honeycomb carbon lattice endows CNTs with excellent electrical [Furthermore, CNT models can be obtained by folding both single-layer and multi-layer graphene sheets, resulting in single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs), respectively, even if real CNT structure is more complex . This chectrical ,65, mechectrical  and therectrical ,68 propepathogenic fiber paradigm” model which states that thin, long and persistent fibrous structures promote both inflammation and carcinogenesis [Similarly to graphene-like materials, CNTs are harmful for tissues and cells due to intrinsic defects ,70 and mogenesis . Neverthogenesis . After iogenesis ,75. Thisogenesis . Furtherogenesis .Collagen is a fibrous protein exhibiting strong hydrophilic behavior, which is insoluble in the majority of organic solvents, and represents the most abundant component of connective tissue. Remarkably, collagen accounts for more than 30 wt.% of total animal proteins, representing the main component of the extracellular matrix in animals. Collagen shows very interesting biological activities, such as the inhibition of tissue damage induced by stretching stress , preservThe medical use of collagen started between the end of the 19th and the beginning of the 20th century with the development of biodegradable sutures for intestine surgery . Neat coThe complex mechanisms of collagen degradation are central issues in the use of neat collagen associated with its high hydrophilicity that induces denaturation pathways and swelling in in vivo experiments . AgarwalA cryogel based on mixed rGO flakes and collagen has found a promising application in bone restoration, as reported by Bahrami et al. . The autA simple sol-gel production route is also effective for GO-containing collagen composites, as demonstrated by Liu et al. . The autInterestingly, CNTs containing collagen scaffolds are more effective as substrates for the proliferation and differentiation of stem cells ,99,100 aChi et al.  reportedKeratin is a protein in which cysteine reaches up to 13 wt.%; it is the major constituent of structures such as feathers and horns. The use of keratin as a biological scaffold is quite complex and requires multistep chemical modification of the native keratin structure.The first step of this process is the extraction of keratin performed in strong chemical conditions using thermochemical or microbial approaches . When th®  and QuickClot® .Nonetheless, keratin hydrogels have been used as effective hemostatic solutions in rabbits affected by lethal liver injury . In addiKeratin and keratin hydrogels have also been used for the regeneration of peripheral nerves, as reported by Sierpinski et al.  using miSong et al.  used an Considering the number of studies reported in the literature, graphene-containing keratin materials represent a new and not-entirely-mature technology, whereas the combination of fibrous keratin with CNT has been more extensively studied. Mahmoodi et al.  followedSimilarly, Asl et al.  replacedSilk is a biopolymer composed mainly of two proteins, fibroin and sericin. Fibroin is a structural protein responsible for the strength and stiffness of silk, while sericin is a jelly protein that promotes adhesion of fibroin fibers together .Fibroin is structured in long parallel β-sheet fibers interacting through hydrogen bonds. Fibroin is a hydrophobic amino-acid-rich material; its ordered folding process underlies the impressive mechanical properties of silk residues, which enable the protein to self-assemble into a stable, ordered structure . As discIzyan et al.  evaluateThere are three main production routes for graphene-like materials containing silk composites: the sol-gel approach , reverseFurthermore, Eivazzadeh-Keihan et al.  tested GColloidal composites based on GO and silk were used to repair myocardial tissue after infarction by mixing with growth factors .CNTs can also be mixed with silk using electrospinning for the production of biocompatible composites with high electronic conductivity and improved mechanical properties , showingd-glucosamine produced as crystalline ordered microfibrils and is a crucial component in the formation of the cell walls of fungi, yeast and arthropod exoskeletons. Chitin has been widely used as an electrospun fiber mat by improving its mechanical properties by functionalization and coupling with polymers [Chitin is a functionalized polysaccharide containing units of β--N-acetyl-polymers . The as-Among chitin derivatives, chitosan is the most used and is produced by the simple partial deacetylation of neat chitin through alkaline or enzymatic hydrolysis . ChitosaSimilarly, Gupta et al.  disperseHyaluronic acid is a biopolymer composed of disaccharide units based on N-acetyl-D-glucosamine and glucuronic acid dimers with a molecular weight up to MDa; it can be found in the majority of biological tissues.Hyaluronic acid use has been explored in viscosurgery for tissue protection during ophthalmological medical procedures, such as lens implantations or cataract surgery, and as a humor vitreous replacement .Outside of surgical applications, hyaluronic acid can be used as a protective agent for wounds due to the moisturizing effect that accelerates tissue healing. Edmonds and coworkers  describeAdditionally, neat hyaluronic acid was used as a synovial fluid replacement and as an additive in cosmetic surgical treatments, inducing increase in the inter-tissue space with a filling effect, as reported by several studies ,170.Neat hyaluronic acid can promote the proliferation of chondrocytes, slowing down cartilage degradation and related ageing problems .Furthermore, neat hyaluronic acid is able to reduce the inflammatory response by modulating cytokine metabolism, with a massive reduction in reactive oxygen species . Neat hyAccordingly, Umar et al.  combinedThe addition of CNTs has created the possibility of producing hyaluronic composites enriched with pluripotent stem cells able to induce neurogenesis together with upregulation of calcium channels. CNT-containing hyaluronic fibers have been used for neural engineering . The autCellulose is the most abundant polysaccharide and is composed of linear chains of glucose units connected to each other through a β 1-4 glycosidic chemical bond. Cellulose is a highly tunable template and can be shaped from nanocrystals to microfibrils based on an isolation methodology involving rearrangement of its hydrogen bond network. However, neat cellulose is not a good biological scaffold due to issues related to cellular interaction. Human cells are unable to adhere and to proliferate on neat cellulose films due to the hydrophilicity of the cellulose surface. This issue has been tackled by tailoring the cellulose hydroxyl residues by inserting species through simple chemical tailoring . CelluloAlternatively, neat cellulose can be blended with other polymers, as reported by Mao et al. . The autThe main feature of nanostructured carbon-based cellulose composites is represented by the strong interaction between cellulose hydroxyl groups and the residual functionalities of carbon materials that tune cell adhesion, growth and proliferation .Graphene and GO flakes dispersed into cellulose matrixes resulted in interesting properties, such as stimulation of osteogenesis ,186, neuSimilar results have been achieved using functionalized MCNTs, as reported by Khalid and co-workers .Nanostructured carbonaceous materials and related biopolymers represent an advanced means of addressing the many issues related to their use as neat materials. CNTs and graphene-related materials are the best candidates to improve both the mechanical and electrical properties of composites. However, several other solutions exist based on nanostructured carbon particles, which are particularly attractive for biomedical applications, such as carbon nano-onions . This paA further important point to be considered is biopolymer isolation, that can represent a cost-determining step in biopolymer production. Similar considerations apply to the production of both CNTs and graphene materials that are still far from being large-scale and sufficiently standardized to meet biomedical industry requirements ,201,202.Nevertheless, the great economical value of biomedical solutions represents a driving force for rapidly achieving significant advancements in the large-scale industrial production of biopolymers, nanostructured carbon species and their composites.This can lead to a new generation of multiresponsive materials useful for applications at the neural interface due to both their chemical and electrical properties ,204. FurThe use of biopolymers represents one of the most interesting frontiers in tissue engineering due to the great potential of biopolymer architectures naturally produced by the molecular engines of biological systems. Their combination with nanostructured carbon represents an additional step towards the production of complex and resilient species with enhanced electrical conductivity and mechanical properties, which will enable the creation of multifunctional composites for many applications in biological fields, such as regenerative medicine, scaffolds, and prosthesis production. Nonetheless, several issues remain unsolved, such as the high cost of biopolymers, CNTs and graphene and related materials, together with their difficult purification, processing, and standardization. Additionally, the degradative pathways of biopolymers are a key point to be considered for in vivo applications, particularly for prosthetic implants where they could represent a considerable advancement compared with the degradative pathways occurring with synthetic-polymer-based composites. Nevertheless, the full exploitation of nanostructured carbon-based biopolymer composites will surely lead to discoveries in many fields, such as regenerative medicine and neuronal implantation.


As a member of the TRIM (tripartite motif) protein family, TRIM56 can function as an E3 ubiquitin ligase. In addition, TRIM56 has been shown to possess deubiquitinase activity and the ability to bind RNA. This adds to the complexity of the regulatory mechanism of TRIM56. TRIM56 was initially found to be able to regulate the innate immune response. In recent years, its role in direct antiviral and tumor development has also attracted the interest of researchers, but there is no systematic review on TRIM56. Here, we first summarize the structural features and expression of TRIM56. Then, we review the functions of TRIM56 in TLR and cGAS-STING pathways of innate immune response, the mechanisms and structural specificity of TRIM56 against different types of viruses, and the dual roles of TRIM56 in tumorigenesis. Finally, we discuss the future research directions regarding TRIM56. The tripartite-motif (TRIM) family of proteins, also known as really interesting new gene (RING)-B-box-Coiled-Coil (RBCC) region proteins, is composed of an N-terminal RING structural domain, one or two B-box patterns, and an α-helical coiled-coil domain, followed by a highly variable carboxyl structural domain from the N-terminus to the C-terminus ,2,3. TRITRIM family members are involved in a wide range of cellular activities and biological processes, including DNA damage repair , RNA binTRIM56 is a member of the TRIM family. TRIM56 was originally reported to regulate the intracellular double-stranded DNA innate immune response . In receThe expression level of TRIM56 is not consistent among different tumor types, and its expression changes are closely related to tumor development and prognosis. This suggests that TRIM56 may play different pro- or anti-cancer functions in different tumor types. In recent years, many studies have revealed the function of TRIM56 in tumor development. TRIM56 is an oncogene in glioma, breast cancer, and Kaposi’s sarcoma ,30,31,32Here, we first describe the structural features and expression characteristics of TRIM56. Next, we focus on reviewing the role of TRIM56 in innate immunity and antiviral processes. We also summarize the role of TRIM56 in tumors. Finally, we discuss the future directions of TRIM56 research. Reviewing the antiviral and tumor regulatory functions and specific mechanisms of TRIM56 is beneficial to provide new ideas for developing novel antiviral drugs and enriching therapeutic strategies against tumors.TRIM56, also known as Ring finger protein 109 (RNF109), is an 81 kDa protein of 755 amino acids encoded by the TRIM56 gene on human chromosome 7. The protein contains three structural domains, a RING domain, a B-box domain, and a coiled-coil domain . BecauseThe RING structural domain is a unique linear sequence of cysteine and histidine residues in a zinc finger structural domain that forms the catalytic center of the ubiquitinating enzyme. Ubiquitination is a very important post-translational modification process that plays roles in innate immune and tumorigenic development ,39,40. UThe B-box structural domain consists of small peptide sequences that contain finger-like protrusion. Although the B-box structural domain also contains a “zinc finger” structure, it generally does not exert E3 ubiquitin ligase activity. There are two distinct isoforms of the B-box, B-box1 and B-box2. Most TRIM proteins contain one B-box2 structural domain or two B-box structural domains, while a few TRIMs, such as TRIM69, do not have either structural domain . The B-bTRIM56 can act as an E3 ubiquitin ligase that catalyzes the ubiquitination of Vimentin, DVL2 (Dishevelled-2), ERα, SAP18 (Sin3A associated protein 18), IκBα, STING, cGAS, and TGF-β-activated kinase 1 (TAK1) ,32,33,36TRIM56 is widely expressed in various tissues of adult mammals . SimilarTRIM family members have direct and indirect antiviral effects, including direct interactions with virus-associated proteins or nucleic acids, or modulation of antiviral signaling pathways associated with host immune function . In receInnate immunity is the first line of defense against pathogen invasion. Upon pathogen invasion, pathogen-associated molecular patterns (PAMPs) are recognized by the pattern recognition receptors (PRRs) of innate immune cells, including retinoic-acid inducible gene-I (RIG-I)-like receptors (RLRs), TLRs, and cell membrane DNA receptors ,51. The TLRs are the first-known PRRs capable of recognizing extracellular viral components that enter the cytoplasm by phagocytosis or endocytosis to induce type I IFN (IFN-I) and pro-inflammatory cytokines to counteract viral invasion. The TLR family contains 13 members . Upon acTRIM56 catalyzes the M1-type ubiquitination modification of TAK1, which enhances the interaction of the TAK1-IKKα complex. The overexpression of TRIM56 enhances the TNF-α-induced activation of NF-κB signaling, whereas the knockdown of TRIM56 has the opposite effect. The C-terminus is the binding region of TRIM56 to TAK1, while the RING structural domain of TRIM56 is the active region of the E3 enzyme and is important for the ubiquitination of TAK1 .Unlike other TLRs, TLR3 uses adaptor Toll-IL-1 receptor (TIR) domain-containing adaptor inducing IFN-β (TRIF) and then activates IRF3 via TBK1/IKKε-mediated phosphorylation. Phosphorylated IRF3 forms a dimer and then translocate to the nucleus, initiating IFN-I expression . TRIM56 cGAS, also known as MB21D1/C6orf150, is considered to be one of the most important cell membrane DNA sensors . Upon reTsuchida et al. found that the overexpression of TRIM56 enhanced IFN-β promoter activation after double-stranded DNA stimulation. TRIM56 interacts with STING and uses it as a substrate for lysine 63-linked ubiquitination. This modification induces STING dimerization, which recruits antiviral kinase TBK1 and induces IFN-β . UbiquitIFN exerts its antiviral effect by inducing the expression of hundreds of ISGs . After IThe known activity of ISGs is still insufficient to explain the antiviral effect of IFN, suggesting that more ISGs with antiviral activity need to be discovered. IFN-I itself enhances the expression of TRIM56 ,48. ThisViruses are a serious threat to the health of living organisms. TRIM56 can act as a direct antiviral restriction factor against many types of viruses, such as positive single-stranded RNA viruses, negative single-stranded RNA viruses, and DNA viruses .The N-terminal protease (N(pro)) of bovine viral diarrhea virus (BVDV) is a proviral interferon antagonist capable of degrading interferon regulatory factor 3 (IRF3) via the proteasome. Although TRIM56 overexpression does not affect the protein levels of N(pro) and IRF3, it still interferes with BVDV replication. The anti-BVDV viral activity of TRIM56 is dependent on its E3 ubiquitin ligase activity and the integrity of its C-terminal region and is not due to a general enhancement of the interferon antiviral response .TRIM56 does not improve cellular resistance to yellow fever virus (YFV), dengue virus serotype 2 (DENV2), or human coronavirus (HCoV) OC43. The anti-flavivirus  function of TRIM56 requires the E3 ligase activity located in the N-terminal RING structural domain and the integrity of its C-terminal portion, whereas anti-HCoV-OC43 restriction only depends on TRIM56 E3 ligase activity. TRIM56 inhibits YFV, DENV2, and BVDV replication by impairing intracellular viral RNA replication, whereas it inhibits HCoV-OC43 progeny production later in the viral life cycle by targeting the viral packaging and release phase rather than intracellular viral RNA accumulation . The aboZika virus (ZIKV) infection is associated with microcephaly and other neurological disorders and is a serious threat to human health . TRIM56 Porcine epidemic diarrhea virus (PEDV) infection causes severe enteric disease in lactating piglets, resulting in significant economic losses to the swine industry . TRIM56 Human immunodeficiency virus (HIV), also known as the AIDS virus, is a retrovirus that causes defects in the human immune system . TRIM56 TRIM56 exerts direct antiviral effects against several positive single-stranded RNA viruses, including members of the Coronaviridae family. 2019-nCoV belongs to the same family of coronaviruses as HCoV-OC43 and causes Coronavirus Disease 2019 (COVID-19). COVID-19 patients were found to have higher levels of TRIM56 expression. There was also a strong positive correlation between the expression levels of TRIM56 and VEGF . This suThe antiviral activity of TRIM56 is virus-specific. TRIM56 was reported to be resistant to only seven positive single-stranded RNA viruses, including Flaviviridae YFV, DENV2, ZIKV, and BVDV; Retroviridae HIV-1; and OC43 and PEDV of the Coronaviridae family . The oveTherapeutic approaches for influenza remain very limited, and genetically mutated drug-resistant influenza virus strains often emerge . UnderstThe antiviral activity of TRIM56 is virus-specific. The overexpression of TRIM56 has been reported not to inhibit three negative single-stranded RNA viruses, VSV, Sendai virus, and human parapneumovirus ,76. WhetTRIM56 expression is upregulated in IFN-treated HepG2 cells and Hepatitis B virus (HBV)-infected liver tissue. TRIM56 inhibits HBV replication with its RING and C-terminal structural domains. The C-terminal structural domain is essential for TRIM56 translocation from the cytoplasm to the nucleus during HBV infection . TRIM56 TRIM56 also promotes IFNα/β expression levels via the cGAS-STING signaling pathway and inhibits the replication of double-stranded DNA virus HSV-1 . TRIM56-The hallmark of Salmonella typhi infection is an acute intestinal inflammatory response, which is mediated by the action of secreted bacterial effector proteins . InflammBy regulating various signaling pathways and proteins in an E3 ligase-dependent or -independent manner, TRIM56 plays different roles in different tumors. It inhibits ovarian cancer, multiple myeloma, lung adenocarcinoma, hepatocellular carcinoma, and leukemia; however, it promotes the development of glioma, breast cancer, and Kaposi’s sarcoma .Ovarian cancer is a gynecologic oncologic disease and one of the major female lethal cancers . EpithelMultiple myeloma (MM) is a group of plasma cell malignancies characterized by the extensive clonal proliferation of tumor plasma cells in the bone marrow . MM accoLung cancer is the most common and lethal malignancy, with lung adenocarcinoma accounting for up to 40% of cases . The redDVL2 is a key regulator of Wnt signaling, which stabilizes β-catenin by catabolizing the APC/Axin/CK1α/GSK3β degradation complex . DVL2 exYang et al. found that downregulated TRIM56 in hepatocellular carcinoma (HCC) patient samples was strongly associated with pathological stage and prognosis . TRIM56 Hepatocellular carcinoma has been associated with viral infections of type B and C . TRIM56 TRIM56 expression is significantly increased in glioblastoma tissues and cell lines. High TRIM56 expression is associated with a poor prognosis in glioma patients ,30. TRIMBreast cancer is the most common cancer in women worldwide ,101. TheKaposi’s Sarcoma (KS) is a common AIDS-associated cancer caused by KS-associated herpesvirus (KSHV) infection . KSHV enTRIM56 is aberrantly expressed in a variety of tumors. TRIM56 was lowly expressed in multiple myeloma , ovarianThis review summarizes the role of TRIM56 in antiviral processes and the development of tumorigenesis. Elucidating the altered expression of TRIM56 and its potential mechanisms in the pathophysiology of cancer and other diseases may provide insights for the development of new and more effective therapeutic strategies. However, there are still no reports on the clinical applications of TRIM56 in small-molecule therapy. A further understanding of the crystal structure of TRIM56 and its ligand-binding complexes could refine the structure-based design for the development of specific small molecules targeting TRIM56, ultimately leading to therapeutic applications.As an E3 ubiquitin ligase, TRIM56 catalyzes the ubiquitination modification of substrates ,36,61,77The innate immune response is the first line of host defense and is characterized by the production of IFN-I and ISGs to limit viral infection and transmission ,113,114.The C-terminal region of TRIM56 mediates protein–protein or protein–RNA interactions between TRIM56 and cellular viral proteins/RNAs and can inhibit viral RNA replication. In addition, the E3 ligase activity of TRIM56 may regulate post-translational modifications of viral proteins and/or host factors to inhibit the replication of positive-stranded RNA viruses. Although TRIM56 is widely expressed in many tissues, the highest expression levels of the protein were detected in the lung and stomach . The preTRIM56 has been reported to exert oncogenic or tumorigenic potential in solid tumors and hematological cancers ,117. The


Two-dimensional (2D) materials offer a prospect of membranes that combine negligible gas permeability with high proton conductivity and could outperform the existing proton exchange membranes used in various applications including fuel cells. Graphene oxide (GO), a well-known 2D material, facilitates rapid proton transport along its basal plane but proton conductivity across it remains unknown. It is also often presumed that individual GO monolayers contain a large density of nanoscale pinholes that lead to considerable gas leakage across the GO basal plane. Here we show that relatively large, micrometer-scale areas of monolayer GO are impermeable to gases, including helium, while exhibiting proton conductivity through the basal plane which is nearly two orders of magnitude higher than that of graphene. These findings provide insights into the key properties of GO and demonstrate that chemical functionalization of 2D crystals can be utilized to enhance their proton transparency without compromising gas impermeability. GO monolayers are presumed to invariably contain a large density of nanoscale pinholes. Here the authors present gas and proton transport measurements which show that GO monolayers can be pinhole-free over micrometer-scale areas. The latter finding was unexpected and contradicted theoretical calculations that suggested insurmountable barriers for proton transsport7. This led to speculation that accidental nanoscale holes were fundamentally necessary for the proton conductivity through graphene10. Those conclusions were based on experiments using chemical-vapor-deposited graphene that often displays such pinholes10. The controversy was resolved only recently, with the demonstration that proton permeation through defect-free graphene is spatially nonuniform and occurs predominantly through wrinkles and nanoripples11. The morphological distortions of the perfect graphene lattice induce local strain and curvature, which considerably reduces the energy barrier for protons12. This finding raises the question of whether intentionally induced lattice distortions13 can be employed to enhance the proton conductivity of 2D materials. In this context, graphene oxide, a chemical modification of graphene, offers a convenient testing ground. GO’s surface is covered with hydroxide, epoxide and other functional groups that are covalently bonded to the graphene lattice and induce nano- and atomic-scale roughness14, that is, a high density of morphological distortions.Defect-free graphene is impermeable to all atoms and molecules18. This in-plane conductivity makes GO a promising additive to Nafion21 and fosters interest in proton-conductive multilayer GO films, so-called GO laminates, which have been extensively examined for their potential as proton-conducting membranes22. However, little is known about proton and molecular transport across the basal plane of GO monolayers . It is universally assumed that there are many nanoscale holes within individual GO monolayers, which enable considerable proton and gas flows28. In this work, we show that high-quality GO monolayers obtained by the Hummers’ method contain large areas that are as impermeable to helium  and other gases as defect-free graphene. The same membranes display proton permeabilities surpassing that of graphene by a factor of ∼50 and approaching those found for monolayers of hexagonal boron nitride (hBN)3 and mica29 which are the 2D materials with the highest proton permeability known so far. Using scanning electrochemical cell microscopy, we show that the enhanced proton transport takes place over a large number of active sites that can be attributed to carbon-oxygen bonds that locally distort the underlying graphene lattice of GO.GO has already attracted considerable interest as a proton conductor because of its high lateral proton conductivity along the basal plane, which is facilitated by surface functional groups30 (Preparation of GO monolayers in Methods). The oxidation process yielded monolayer crystals that displayed a prominent D band in their Raman spectra . To the best of our knowledge, He leak tests of GO monolayers were not reported in earlier literature, probably due to challenges associated with making suspended GO membranes that are more fragile than those made from graphene.GO monolayer flakes with large lateral sizes of 10 to 30 μm were synthesized by the Hummers’ method and exfoliated using short-duration ultrasonication and step-wise separation, as reported previously3–104 atoms s−1 under a pressure of 1 bar31. This means that, in principle, many angstrom-scale defects could be present in our GO membranes but remained indiscernible using the He-leak detector. To check for such angstrom-scale pinholes, we employed a recently developed technique that can sense gas flows of as little as a few atoms per hour, that is, provides more than 10 orders of magnitude higher sensitivity than that of the best helium-leak detectors31. The technique is based on micrometer-size wells etched into hBN or graphite monocrystals, which are then sealed with 2D crystals2  − δ(0) as a function of the time, t, that the devices spent under 1 bar of helium (kinetic diameter of 2.6 Å). For most of the devices (∼70%), no Δδ could be noticed over a one-month period within our experimental accuracy for Δδ of better than 1 nm. This demonstrates that those GO membranes were completely impermeable to He, similar to pristine (non-oxidized) graphene31. Note that, if a single angstrom-scale defect were present in our GO membrane, it would rapidly inflate and deflate by tens of nm, as reported previously31. The remaining 30% of the microcontainers without AFM-visible pinholes either exhibited some bulging or failed completely. For completeness, we performed similar experiments exposing our microcontainers to other inert gases  and reached the same conclusions  graphene that was not subjected to any oxidation processes. For electrical measurements, the devices were placed inside a chamber filled with humid hydrogen to ensure the high proton conductivity of Nafion (Proton conductivity measurements in Methods).Having established that gas-permeable defects were absent in GO membranes without AFM-visible damage, we proceeded to examine proton transport through GO. We used the same devices that passed the impermeability test with the He-leak detector described in the previous section. These membranes were coated on both sides with a proton-conducting polymer (Nafion) and electrically connected with proton-injecting electrodes Fig. , inset. −2, in agreement with the earlier reports11. In contrast, GO monolayers were notably more transparent to protons, exhibiting conductivity of 110 ± 70 mS cm−2, which is on average ∼50 times higher than that of pristine graphene  are much smaller than He atoms. To investigate the latter possibility, we examined GO membranes using scanning electrochemical cell microscopy (SECCM), which provided maps of GO’s proton conductivity with nanoscale resolution.For both pristine graphene and GO, we found the measured currents to vary linearly with applied bias Fig. , and theene Fig.  and comp11. The devices were similar to those used in the electrical measurements reported in Fig. For SECCM, we followed the methodology described in our recent study of proton transport through graphene and hBN crystals10. Instead, we observed many sites within the current range of 200-300 pA, which is approximately two orders of magnitude higher than in our reference devices using pristine exfoliated graphene, in agreement with ref. 11  graphene36, which led to a bigger meniscus on the GO surface (exceeding the SECCM tip diameter) and hence an overestimation of the areal conductance  graphene that clearly displayed such pinholes14. Indeed, it has recently been shown that proton permeation through pristine graphene monolayers is strongly facilitated by nonflat regions such as nanoscale ripples where local strain reduces the energy barrier for proton permeation11. The functional groups on GO’s surface also create microscopic distortions, acting somewhat like adsorbates that are known to cause nanoripples on pristine graphene39. Our density functional theory calculations  with an ESCA 2SR high-throughput X-ray photoelectron spectrometer (Scienta Omicron GmbH). The instrument is equipped with a monochromated Al Kα source , an Argus CU multipurpose hemispherical analyser and an electron flood gun for less conductive samples. All the peaks were calibrated using the C1s photoelectron peak at ∼284.8 eV for graphitic carbon. Spectral deconvolution was performed using CASAXPS (www.casaxps.com) with Shirley-type backgrounds. Supplementary Fig. 44: non-oxygenated ring C = C (∼284.8 eV), hydroxyl group C-OH (∼285.6 eV), epoxy group O-C-O (∼286.9 eV), carbonyl C = O (∼287.8) and carboxylate O–C = O (∼288.8 eV). The inset of Supplementary Fig. Graphite oxide was obtained using the Hummers’ method and the material was exfoliated into monolayers by short-duration sonication in water (3 minutes under 40 W power). Large monolayers >10–20 µm) were separated from smaller ones using centrifugation procedures0–20 µm w−1) was drop-cast onto an oxidized silicon wafer covered with a bilayer polymer film  that was used as a sacrificial layer when transferring selected flakes to make the final devices. The deposited GO flakes were examined using both optical and atomic force (AFM) microscopes to check their thickness and quality. Supplementary Fig. 45. Areas within the flakes without visible defects such as wrinkles46, tears or cracks were chosen for device fabrication  were etched into silicon-nitride/silicon substrates (500 nm of silicon-nitride) using photolithography, wet etching and reactive ion etching, as reported previously31. In brief, polymer rings with inner and outer diameters of 0.5–1 µm and 1.5-2 µm, respectively, were defined by e-beam lithography on top of atomically flat areas (free of terraces) of cleaved graphite or hBN monocrystals. The rings were used as a mask to dry-etch the crystals and form an array of microwells that were ∼80 nm deep , and the I-V curves were recorded using Keithley SourceMeter 2636 A. Measurements were limited to T < 60 °C to prevent GO membranes’ rupture. We emphasize that, despite the relatively high conductivity of GO membranes, our devices’ resistance was still ~100 times higher than that of devices with empty apertures 3. This assured that the series resistance arising from a finite conductivity of Nafion could be neglected and we measured the intrinsic proton properties of GO monolayers.To measure proton conductivity of GO, both sides of the freestanding membranes were coated with a Nafion solution . Proton injecting electrodes were carbon cloth with Pt-on-carbon acting as a catalyst. The devices were measured in a humid hydrogen atmosphere  due to Ebias provides qualitative information on the local degree of wetting11. Upon the approach of the nanopipette to the surface, there is a characteristic ‘jump-to-contact’ as the meniscus wets the surface, resulting in an abrupt change in IDC . On the other hand, the broad distribution of ‘jump-to-contact’ currents for GO is consistent with an inhomogeneous functionalization in the membrane. The wetting behavior discussed so far is mirrored when the probe is withdrawn. In this case  and projected augmented wave (PAW) method57. The kinetic energy cut-off and the k-point meshes were set to 500 eV and 7×7×1, respectively58. The van der Waals interactions were considered and treated by the semi-empirical DFT-D2 method60. All atoms were allowed to fully relax to the ground state and the spin-polarization was included. We used climbing-image nudged elastic band (CI-NEB) methods to search for transition states (TS)62. The latter correspond to states with the highest total energy Emax along the reaction path. Accordingly, the energy barrier Eb was evaluated as the difference between Emax and the initial energy Ein.DFT calculations were performed using the VASP packagen) of functional groups. Supplementary Fig. sp3-sp3 C-C hybridization. The largest buckling happens if all the carbon atoms within a single hexagon ring are bonded with oxygen (n = 3). We then calculated the energy for the proton-GO system as the proton transfers through the distorted hexagon ring. As shown in Supplementary Figs. Eb for proton translocation is notably lowered with increasing the number of attached oxygen atoms. At n = 3, where all the carbon atoms are saturated by oxygen . The observed trend in Eb is inversely correlated with that in the calculated length of C-C bonds in the buckled graphene lattice (Supplementary Fig. To model GO, oxygen functional groups were attached to the graphene lattice. For simplicity, only epoxy groups, that are most abundant in our GO films (Supplementary Fig. Supplementary InformationPeer Review File


We know that speech planning in conversational turn-taking can happen in overlap with the previous turn and research suggests that it starts as early as possible, that is, as soon as the gist of the previous turn becomes clear. The present study aimed to investigate whether planning proceeds all the way up to the last stage of articulatory preparation  and what the timing of this process is. Participants answered pre-recorded quiz questions (being under the illusion that they were asked live), while their tongue movements were measured using ultrasound. Planning could start early for some quiz questions , but late for others . The results showed no evidence for a difference between tongue movements in these two types of questions for at least two seconds after planning could start in early-planning questions, suggesting that speech planning in overlap with the current turn proceeds more slowly than in the clear. On the other hand, when time-locking to speech onset, tongue movements differed between the two conditions from up to two seconds before this point. This suggests that articulatory preparation can occur in advance and is not fully tied to the overt response itself. Imagine you are participating in a television quiz in which you have to answer several knowledge questions, each with a five second deadline. Listening to the quizmaster, you hear “Which character, also called 007…”. Even though it is clear that the question is not over yet, hearing only this first part of the question allows you to start retrieving the answer to the question. Will you indeed start retrieving the answer, instead of waiting for the end of the question? Or perhaps you will go even further and you will continue planning the answer (‘James Bond’) as far as positioning your tongue in the correct position, such that after the question is over (“… appears in the famous movies?”) you have already prepared your articulators and can utter the correct answer as fast as possible? The present study investigates, using ultrasound measures of tongue movements, whether speakers, when planning responses in advance, go so far as to prepare their articulators in advance as well, and if so, what the timing of this process is.turns are counted. Relatedly, not all turns appear to be contingent on the previous turn, but a substantial amount of turns within conversational corpora, at least when they are automatically annotated, appear to be continuations of a previously started turn ).For future research, corpus studies investigating natural conversation  areWe argue that the (perceived) interactive aspect is especially relevant to include in such experiments because it may quantitatively or qualitatively change the processes involved. In other aspects, recreating natural conversation in controlled circumstances is also challenging. For example, the present study did not include visual aspects of interaction  and was restricted to question-answer sequences. Although phone conversations, and questions followed by socially expected answers are an important part of natural conversation, future research should broaden its scope to face-to-face interaction and other types of conversational sequences  as well.When taking turns in conversation, communicators have to be listeners and speakers at the same time, since they often start planning their own response while still listening to the previous turn. However, this dual tasking is not without cost. The present study showed that early planning can proceed all the way up to articulatory preparation in the form of tongue movements before speech onset, and arrive there some time (in the present study up to two seconds) before the response starts. This is in accordance with earlier observational work suggesting that articulatory preparation is not strictly tied to the response itself. However, we also found no evidence for early articulatory preparation, which is in accordance with the body of evidence showing that the planning process appears drawn out and less efficient when performed in overlap with understanding of the ongoing turn.S1 Text(PDF)Click here for additional data file.