After the lockdown of Wuhan on January 23, 2020, the government used community-based pandemic prevention and control as the core strategy to fight the pandemic, and explored a set of standardized community pandemic prevention measures that were uniformly implemented throughout the city. One month later, the city announced its first lists of “high-risk” communities and COVID-19-free communities. Under the standardized measures of pandemic prevention and mitigation, why some communities showed a high degree of resilience and effectively avoided escalation, while the situation spun out of control in other communities? This study investigated: 1) key factors that affect the effective response of urban communities to the pandemic, and 2) types of COVID-19 susceptible communities.This study employs the crisp-set qualitative comparative analysis method to explore the influencing variables and possible causal condition combination paths that affect community resilience during the pandemic outbreak. Relying on extreme-case approach, 26 high-risk communities and 14 COVID-19 free communities were selected as empirical research subjects from the lists announced by Wuhan government. The community resilience assessment framework that evaluates the communities’ capacity on pandemic prevention and mitigation covers four dimensions, namely spatial resilience, capital resilience, social resilience, and governance resilience, each dimension is measured by one to three variables.The results of measuring the necessity of 7 single-condition variables found that the consistency index of “whether the physical structure of the community is favorable to virus transmission” reached 0.9, which constitutes a necessary condition for COVID-19 susceptible communities. By analyzing the seven condition configurations with high row coverage and unique coverage in the obtained complex solutions and intermediate solutions, we found that outbreaks are most likely to occur in communities populated by disadvantaged populations. However, if lacking spatial-, capital-, and governance resilience, middle-class and even wealthy communities could also become areas where COVID-19 spreads easily.Three types of communities namely vulnerable communities, alienated communities, and inefficient communities have lower risk resilience. Spatial resilience, rather than social resilience, constitutes the key influencing factor of COVID-19-susceptible communities, and the dual deficiencies of social resilience and governance resilience are the common features of these communities. The global outbreak of COVID-19 has made prevention and mitigation of the pandemic an issue of urgent concern internationally  and its Wuhan is the capital of Hubei Province. The city is composed of 15 administrative districts and 1107 communities. Until 2020, Wuhan has a permanent resident population of 12,32 million, ranking the sixth-largest city in China . BesidesIn the Chinese context, communities are the first state-backed organizations  and hencOn February 24, the Wuhan New Crown Pneumonia Pandemic Prevention and Control Headquarters announced the first list of 278 “high-risk” communities and residential blocks in Wuhan  . On MarcResilience is originally a concept from physics that refers to the ability of a substance or system to return to its original position after being displaced , 14. In Like community resilience definition, there is no consensus as to how it should be measured. Depending on different conceptualization approaches and specific resilience domains to be assessed, measurement tools vary from quantitative methods relying on preexisting datasets, to qualitative and participatory framework using focus groups, interviews, and mixed approaches which combine quantitative and qualitative data . Among tDeveloping a proper and adequate community resilience measurement framework remains a complex challenge. Clark-Ginsberg et al. point out that “community resilience measurement is less about developing measures that can satisfy all design criteria and more about minimizing the negative elements of measurement choices and maximizing the positive” , and thaDespite their important theoretical and empirical contributions, the current literature presents some limitations. First, studies on community resilience mostly focus on the community’s ability to adapt to natural disaster risks in the context of climate change , researcTo complete the theoretical and methodological deficiencies of existing research, this study adopted a qualitative comparative method to investigate the influencing factors and their dynamic interactions that affect community resilience during the pandemic outbreak. Through the analysis of 40 urban communities in Wuhan, we identified key factors and common features that determine communities’ capacity for pandemic prevention and mitigation, as well as types of communities susceptible to the COVID-19 pandemic. This study aims to provide theoretical inspiration for urban communities to respond to the same type of public health risk.Qualitative comparative analysis (QCA) is a research method oriented toward small and medium sample case studies (10–40). Through a comparative analysis of causal conditions in multiple cases, it seeks to reveal multiple conjunctural causation relationships between conditional variables and outcome variables . Multipli configurations in total, i = number of condition variables). A specific configuration is the combination of some condition variables and an outcome variable, which might correspond to several observed cases. In this sense, QCA is useful for data exploration and case interpretation in a synthetic way, as a relevant tool for typology-building [At present, QCA has developed three research methods: crisp-set qualitative comparative analysis (csQCA), fuzzy-set qualitative comparative analysis (fsQCA), and multi-value qualitative comparative analysis (mvQCA). Among them, crisp-set QCA is the most widely used method by researchers –39. Its building . It can building .To examine whether there is a necessary and sufficient relationship between a given condition variable and an outcome variable, one should measure the consistency and coverage of a single condition variable in the overall sample cases.The univariate necessity and adequacy analysis are assessed by the consistency index. The formula for calculating the consistency index is as follows:If variable X  is a sufficient condition for Y (outcome variable), the consistency index should be greater than 0.8 . At the This indicator describes how well the condition (or combination) X interprets the outcome Y. The larger the value of the coverage index, the stronger the explanatory power of X to Y.This study chooses csQCA as the analysis method. The reason is as follows: First of all, the boundary of the condition variables and outcome variables involved in the study is relatively clear, and can be divided into two categories by “true” or “false”. Second, with the combination comparison and calculation of multiple concurrent conditions in multiple cases, a csQCA study can help identify the necessary conditions and sufficient conditions combination paths that lead to the emergence of COVID-19-susceptible communities. This can partly compensate for the limitations of current quantitative or qualitative researches on this issue. In addition, through the analysis of multiple concurrent configurations between condition variables and outcome variables, qualitative comparative research can also help reveal the complex dynamic interactions between factors that influence community resilience.This study integrated and improved the assessment frameworks put forward by Bruneau et al. and Peacock et al., and developed a community resilience assessment framework covering the four dimensions of spatial resilience, capital resilience, social resilience, and governance resilience. Each dimension is measured by 1–3 variables. As the total number of variables in a QCA is usually limited from four to seven , the stuThis term refers to the resilience of community physical space, building environments, and public infrastructure, such as community space planning, public facilities, characteristics of buildings and residential houses, and disaster prevention facilities , 23, 43 Communities incorporate a stock of human- and economic capital that defines their capital resilience. This resilience is defined by the community population characteristics, such as education and skills, the employment rate, and the average income level of families , 23. ComIt involves the quality and stock of a community’s social capital, which is reflected through the number of community social organizations, the relationship between residents, and their participation in community affairs , 23. ResIt refers to the level of a community’s governance capabilities and the abundance of governance resources. It is reflected through the completeness of the community governance structure, the community decision-making and implementation capabilities, and the adequacy of human and institutional resources on community governance , 33, 54.Lastly, as for the outcome variable “Whether it is a COVID-19 susceptible community”, we assign a value of 1 to high-risk communities and 0 to COVID-19 free communities . The data for the condition variable “whether community administrators have received complaints due to poor implementation of anti-pandemic measures” are taken from the “Leadership Message Board” of People’s Daily Online (liuyan.people.com.cn) and Weibo (weibo.com). Some information that is difficult to verify through the Internet, such as whether the physical spatial characteristics of individual communities are high-rise buildings or old-broken-small housing, was verified by residents in Wuhan through telephone interviews.Research data mainly are originally collected from government information disclosure via the Internet and social networks. The data related to the cases are taken from the China Community website; category 2(configurations 2 and 6) is sufficient in capital resilience but vulnerable in spatial, social, and governance resilience; category 3(configuration 7) is sufficient in spatial and capital resilience, but vulnerable in social and governance resilience.Among the seven configurations, six of the configurations are related to insufficient spatial resilience, four of the configurations are related to insufficient capital resilience. Spatial resilience thereby is the main factor that influences the degree of community resilience, the results confirm the findings of the above analysis of the necessary conditions for COVID-19 susceptible communities. Lastly, insufficient social resilience and governance resilience appear in all of the seven configurations, it’s the common feature of all COVID-19-susceptible communities.The above seven condition combination paths involve three types of COVID-19-susceptible communities. This article names them vulnerable communities , alienated communities (configurations 2 and 6), and inefficient communities (configuration 7). See Table Vulnerable communities covered 57.7% of susceptible community cases. Because of its overall weakening characteristics in the four dimensions of spatial resilience, capital resilience, social resilience, and governance resilience, vulnerability is its core feature, so this type of community is named a vulnerable community. Its condition combination is configuration 1, configuration 3, configuration 4, and configuration 5.First, in terms of spatial features, vulnerable communities fall into two categories. One is characterized by high-rise buildings and usually consists of social housing (such as Case 1), resettlement housing (such as Case 5), or urban villages . The other involves large non-gated old communities with poor common facilities and living conditions, namely old-broken-small communities. Second, in terms of human- and economic capital, vulnerable communities are urban areas populated by disadvantaged groups. The elderly, disabled, low-income households, and floating population account for a large proportion of the total community population. Third, the social capital of vulnerable communities is relatively weak. They are usually communities established after the year 2000 and belong to young communities. Residents come from different parts of the country, and their relationship networks and social bonds are weak. The apparent exceptions, such as cases 4 and 12, where the communities were established early on, however, share the common trait that they have only got a few social organizations. Therefore, they lack the channels and platforms for enhancing communication and cooperation among residents. Finally, vulnerable communities also belong to communities with low governance efficiency. These communities often lack governance resources. Except for the establishment of a general Party branch at the community level, there is no other Party branch, and community Party members have not been effectively organized and mobilized. This means these communities lack effective leadership organizations and active participants. In these communities, administrative members often receive complaints from residents in terms of competence and responsibility. Therefore, vulnerable communities lack robust resilience to effectively meet the needs of community residents for pandemic prevention and control.After being designated as high-risk communities, vulnerable communities mainly rely on the support and help of external resources to overcome the pandemic. During the period of COVID-19, the general practice of Wuhan City was to support high-risk communities one-on-one by higher-level official departments, establishing temporary Party branches that played the role of leadership, sending extra Party members and government employees to augment the community’s pandemic response personnel, relying on the authority of higher-level departments and Party organizations to mobilize community residents and organizations to work together to fight the pandemic.The main difference between alienated communities and vulnerable communities is that the former ones are not areas populated by vulnerable groups. The residents’ socio-economic status and human capital are in the middle or even the upper level of society. The reason why they are named alienated communities is that these communities are mostly young communities with a short history of establishment in which residents are strangers to each other, that is, alienated. Its condition combinations are configurations 2 and 6. The alienated communities cover 34.6% of COVID-19-susceptible community cases.The vulnerability of alienated communities is mainly reflected in three dimensions: spatial resilience, social resilience, and governance resilience. They are usually new communities built around the real estate economy after the rise of the commercial housing market. In terms of housing type, they usually involve high-rise modern buildings. The residents are similar in social and economic status, that is, the middle- or upper class. However, these communities are often loosely organized communities, with few social organizations and low participation in community affairs. Party branch building is imperfect. As it is difficult for the homeowners to establish an autonomy committee, the property management agency thereby lacks supervision, and its conflicts with the homeowners are numerous. Community residents’ committees often find it difficult to gain the trust and cooperation of residents because of their bureaucratism in daily work. Due to their high socioeconomic status, community residents have a relatively strong awareness of rights, and they often put higher service requirements on community administrators. Additionally, the existing property management agencies and residents’ committees cannot effectively meet the expectations of residents. As a result, the administrators of this type of community are often vulnerable to complaints and resistance from residents during the pandemic. In short, despite the strong capital resilience of alienated communities, the lack of resilience to the pandemic in the design and planning of physical residential space, as well as insufficient social resilience and governance resilience, leaves this type of community vulnerable to COVID-19.Inefficient communities do not involve high-rise buildings or old-broken-small housing, nor are they inhabited by disadvantaged groups, but are communities lacking both social resilience and governance resilience. Because of their low collective action efficiency and governance efficiency, they are called “inefficient communities.” Their condition combination is configuration 7. Case 6 and Case 14 in this study belong to this type of community, covering 7.7% of risk-susceptible community cases.Case 6 is a good illustration of inefficient communities. It involves a new community located in Qingshan District, Wuhan, established in 2002. According to the community’s information registered on the “China Community Network”: “The community covers an area of 141,700 square meters, with a total construction area of 222,000 square meters and a green area of 2.27 hectares. The community is surrounded by trees and has a beautiful environment. It is composed of five independent courtyards. There are 37 residential buildings, 160 unit doors, 2,289 households with 7,819 people, including 4 low-income households, 46 disabled people, and 243 elderly living alone.” In terms of physical space characteristics, the community has a low floor area ratio and a high greening rate. It is characterized by neither high-rise buildings nor old-broken-small housing, so it has strong spatial resilience. In terms of its capital resilience, the population of disadvantaged groups accounted for approximately 3.7% of the total population of the community. It is not a community populated by disadvantaged groups. It has strong resilience in human capital and economic capital. However, the community was established in 2000, it is a young community. The number of registered social organizations is only 3, which is lower than the average of 40 community cases. The community has only one Party branch composed of three Party members. The number of Party members is limited. The community has not received any reward from high-level governments. Moreover, during the pandemic, the community administrators received complaints from residents for not being “serious and responsible” . The main reason for inefficient communities to become pandemic-susceptible communities is their weak social resilience and governance resilience; therefore it is difficult for them to resist the spread of the virus during the outbreak.The results of analysis of necessary conditions of the seven variables revealed that spatial resilience is the key influencing factor of COVID-19 susceptible communities, and the seven condition configurations showed that the dual deficiencies of social resilience and governance resilience are the common features of these communities. These issues are further discussed below.From the aforementioned univariate necessity analysis, it can be seen that insufficient spatial resilience constitutes the key factor of pandemic-susceptible communities. Among the 26 high-risk community cases, 22 cases lack spatial resilience, with a case coverage rate of 84.6%. Two types of communities are characterized by insufficient spatial resilience: First, residential communities are dominated by large-scale high-rise buildings, with high population density and frequent intercrossing between residents. The vertically enclosed shared facilities of high-rise buildings, such as elevators, ventilation facilities, and sewage facilities, can easily cause the virus to spread in the same building space. The second is the “old-broken-small” communities. Residential buildings usually have poor ventilation and lighting conditions, lack of basic sanitation facilities (it is common for many people to share toilets and kitchens), and poor environmental sanitation  making iAmong the 26 high-risk community cases, a total of 15 communities involved disadvantaged groups inhabited areas, accounting for 57.7%, and 13 of the latter lacked spatial resilience. However, among the 14 COVID-19-free cases, there were also 7 communities inhabited by disadvantaged groups. Among them, two communities lacked spatial resilience, but had strong social resilience and governance resilience; the other 5 communities had strong spatial resilience, social resilience, and governance resilience. The above data show that the key reason why communities inhabited by disadvantaged groups have become pandemic-susceptible communities may be that these groups often live in communities that lack spatial resilience, not their weak human and economic capital resilience. As long as communities lacking capital resilience have sufficient social resilience and governance resilience, they can also be protected from the impact of the pandemic.If we closely examine the 14 cases of COVID-19-free communities, it can be found that communities inhabited by disadvantaged groups with sufficient social resilience and governance resilience are all old neighborhood communities with numerous social organizations. In this type of community, residents are relatively homogeneous in member structure and status. Most of the residents have known each other for decades, they have relatively stable and continuous social networks, and there exist mutual trust and cooperation relationships with each other. Traditional authority and administrative organizations, such as Party branches and residents’ committees, are relatively efficient, and they enjoy a high degree of authority and recognition among residents, so they have strong mobilization capabilities to enforce specific measures. The existing endowments and resources of the community can be converted into effective collective action efficiency and governance efficiency at the critical moment of disaster, providing resilience for efficient disaster response.Although each of the three types of COVID-19 susceptible communities has its unique characteristics, they share common features with a lack of social resilience and governance resilience.Firstly, communities susceptible to COVID-19 are often communities low on organization and resident participation, in other words, lacking social resilience. In these communities, residents have not formed cooperative relationships based on mutual trust. Instead, the residents are unlikely to provide mutual assistance in the face of disasters, and mainly rely on the residents’ committee, property management agencies, and higher-level governments to fight the pandemic,It is worth discussing that the number of social organizations is usually regarded as an important indicator to measure the stock of social capital in a community , 23. CanSecondly, COVID-19-susceptible communities have got insufficient governance resilience. The imperfect governance structure and the replacement of communities’ autonomy with administrative management are common features of most urban communities in China. It is common for old community residents’ committees to take charge of property management, while new commercial housing communities often lack the self-governing organization, namely a homeowners’ committee. An outstanding problem brought about by the governance structure is insufficient human resources for community governance. Once the community was hit by a critical disaster, the community’s emergency management personnel was overwhelmed. Moreover, the extension of the hierarchical administrative management style in communities not only leads to the weak self-government ability of the community residents, but also makes it difficult for the coordination of multiple governance bodies such as the grass-roots formal organizations (residents’ committees), informal organizations , market organizations (property management agencies), and residents. The hierarchical administrative relationship between residents’ committees and higher-level governments has also led to the lack of initiative and autonomy of the former. Thereby, in the process of disaster response, residents’ committees usually show behavioral inertia and passively execute orders and tasks of higher-level governments, cannot act decisively, autonomously, and respond flexibly in the face of a crisis. Lack of decision-making capacity and adaptability of policy implementation to local conditions constitute two important reasons why some communities become high-risk communities.Based on the assessment framework of community resilience, this study adopts a crisp-set qualitative comparative analysis method to examine the pandemic prevention and control capacity of 40 communities in Wuhan during the COVID-19 pandemic. Subsequently, the paper discusses the influencing variables and their configuration paths affecting the risk resilience of urban communities. The study found that vulnerable communities, alienated communities, and inefficient communities constitute three types of COVID-19-susceptible communities. Vulnerable communities inhabited by disadvantaged groups are not uniquely vulnerable to the pandemic as middle-class and wealthy communities can also be high-risk areas. The spatial dimension, rather than the capital dimension, constitutes the key influencing variable that affects the risk resilience of communities. Insufficient spatial resilience constitutes a necessary condition for COVID-19-susceptible communities, and its influence exceeds the human and economic capital dimension.The contributions of this study are double: First, based on the QCA approach, we have identified the key influencing factors of pandemic-related community resilience, which is a missing element in the current literature; Second, through analyzing the consistency of seven condition variables, we discovered that the spatial resilience rather than capital or social resilience constituted the key factor of community resilience in the situation of a pandemic, finding constitutes a novelty compared to existing ideas which tend to emphasize the imbalanced importance of social network or socio-economic capital of the community. This study pointed out the main reason that communities populated by disadvantaged populations are vulnerable to COVID-19 might be the physical structures and environment of these communities usually lack spatial resilience, rather than their disadvantaged socio-economic capital.Our findings suggest city policy-makers in new similar crises pay more attention to communities and places that lack spatial resilience, including identifying these places beforehand, taking appropriate risk precautions such as strengthening pandemic surveillance and prevention, taking locking-down measures in very early stage, transferring populations to places with strong spatial resilience if necessary. Meanwhile, this study confirmed the existing hypothesis that COVID-19-susceptible communities are the result of a comprehensive combination of weaknesses in multiple resilience dimensions. Empowering communities’ social capital and economic capital, as well as improving their governance capacity, constitute indispensable measures to improve a given pandemic susceptible community’s ability to respond to the disaster.


Wnt1-Cre lineage specific role of Gpr161 during mouse embryonic development. We observed three major gross morphological phenotypes in Gpr161 cKO  fetuses; protrusive tectum defect, encephalocele, and craniofacial skeletal defect. The overall midbrain tissues were expanded and cell proliferation in ventricular zones of midbrain was increased in Gpr161 cKO fetuses, suggesting that protrusive tectal defects in Gpr161 cKO are secondary to the increased proliferation of midbrain neural progenitor cells. Shh signaling activity as well as upstream Wnt signaling activity were increased in midbrain tissues of Gpr161 cKO fetuses. RNA sequencing further suggested that genes in the Shh, Wnt, Fgf and Notch signaling pathways were differentially regulated in the midbrain of Gpr161 cKO fetuses. Finally, we determined that cranial neural crest derived craniofacial bone formation was significantly inhibited in Gpr161 cKO fetuses, which partly explains the development of encephalocele. Our results suggest that Gpr161 plays a distinct role in midbrain development and in the formation of the craniofacial skeleton during mouse embryogenesis.Sonic hedgehog (Shh) signaling regulates multiple morphogenetic processes during embryonic neurogenesis and craniofacial skeletal development. Gpr161 is a known negative regulator of Shh signaling. Nullizygous Gpr161 mice are embryonic lethal, presenting with structural defects involving the neural tube and the craniofacies. However, the lineage specific role of Gpr161 in later embryonic development has not been thoroughly investigated. We studied the  Sonic hedgehog (Shh) signaling is one of the critical mammalian morphogen signaling pathways that regulates dorsoventral neural tube patterning , neural Mammalian neural crest cells (NCCs) arise from the dorsal neural tube which delaminate from their site of origin and subsequently migrate and differentiate into the designated cell types in peripheral organs . SeveralGpr161 hypomorphic mutant mice had both congenital cataracts and spina bifida , and facial nerve ganglia (VII) at E9.5. By E11.5, the Cre expression was widely expanded into the neural tube, including the mid/hindbrain and most of the orofacial and pharyngeal arch regions   or Gpr161f/f (flox control) did not show any similar abnormal phenotypes  . The Gprenotypes . Spinal the face . We alsond E18.5 .Gpr161 cKO fetuses  . The pHH3 positive cells tend to be located in the mitotic zone of VZ  , whereasne of VZ  in WT wh fetuses . In addi fetuses .Gpr161 cKO fetuses, we measured Shh and Wnt signaling activities within dissected midbrain tissues from floxed/Cre controls and Gpr161 cKO fetuses  and β-catenin , were increased, and one of Wnt target genes, CyclinD1, was increased , Gpr161f/+;Cre/+ (Cre control), and Gpr161 cKO  fetuses at E13.5 , Fgf8, Spry1 , Hes3 , Wnt1  and Draxin  (Gpr161 cKO fetuses. The Gene Ontology (GO) analysis further demonstrated that DEGs were highly enriched in the processes involved with neurogenesis, neuronal differentiation, neuronal morphogenesis, and mitotic cell cycle (Gpr161 cKO.To further unbiasedly identify the molecular basis of protrusive tectum phenotypes in at E13.5 . The hea control . The topgulated) . These rll cycle . Taken tGpr161 cKO fetuses. We observed up to 69% of the Gpr161 cKO fetuses had encephalocele  and Alizarin Red S . We observed a significant loss of mineralized skull and facial bones in Gpr161 cKO fetuses at E17.5  during embryonic midbrain morphogenesis.As previously reported  and shownd bones . The brastin-Cre . We also fetuses , indicatncreased , 4B, andncreased  was inhid Nkx6.2 , which wf Gpr161 . Corticaferation . As PtchCyclinD1, was increased  were generated and graciously provided by Dr. Saikat Mukhopadhyay  and the detailed information was previously reported (Wnt1-Cre (#009107), Nestin-Cre (#003771), and Rosa26-lsl-LacZ (#003474), were purchased from Jackson laboratory. The genotypes of the mice and embryos/fetuses were determined by PCR-based genotyping.All mice were housed and handled according to the guidelines approved by the Institutional Animal Care and Use Committee (IACUC) of The University of Texas at Austin. reported . The traWnt1-Cre and Rosa26-LacZ. The harvested embryos were fixed, and β-gal staining was performed according to the manufacturer’s instruction (Millipore Sigma). The images were captured by Leica stereomicroscope with a Nikon digital camera.Embryos were collected at E9.5 and E11.5 from timed mated breeding pairs between Gpr161f/f and Gpr161f/+;Wnt1-Cre/+. Collected fetuses were fixed, paraffin embedded, and sectioned with 4 um-thickness. The paraffin sections were deparaffinized, dehydrated, antigen-retrieved, blocked (blocking solution: Thermo Fisher scientific), and incubated with primary antibodies  diluted with Lab Vision™ Antibody Diluent Quanto (Thermo Fischer scientific) overnight at 4°C. After washing, sectioned were incubated with Horseradish peroxidase (HRP) polymer conjugate  and DAB (Boster Bio). The sections were counterstained with hematoxylin (Thermo Fisher scientific). Images were captured with All-In-One Fluorescent (Keyence) microscope using a ×2 and ×20 objective. To assess the positive cells for each proliferation marker Ki-67 and pHH3 in the dorsal midbrain regions of each embryo, the images were digitized and analyzed with Fiji (NIH), with image analysis. For quantification, a total of 4–6 fields per dorsal midbrain regions per each embryo were captured at ×20 magnification. Each field was divided into 100 equal squares and subjected to color deconvolution. For each of the images, the Shanbhag threshold (Fetuses were harvested at either E13.5 or E15.5 from timed mating between hreshold  was appl® 800CW goat anti-rabbit IgG and 1RDye® 680CW goat anti-mouse IgG secondary antibodies (LI-COR). The images were captured by Odyssey® (LI-COR).The midbrain tissues were dissected from E13.5 mouse fetuses as described . The disThe dissected midbrain tissues from E13.5 mouse fetuses were lysed with Trizol and total RNA was purified with Direct-zol RNA kit (Zymo research). For quantitative RT-PCR, 500 ng-1 µg of RNA was used to synthesize cDNA using iScript reverse transcription Supermix kit (Bio-Rad). The quantitative RT-PCR was performed using SsoAdvanced™ Universal SYBp < 0.05 genes with <1 count per million (cpm). Any gene with a p-value greater than FDR, after Benjamini-Hochberg correction for multi-testing, was deemed significantly differentially expressed under the test condition as compared to the control. The dataset was analyzed by the Gene Ontology (GO) enrichment analysis.The tissues were harvested as described in Midbrain dissection and total RNAs were extracted with Direct-zol RNA kit (Zymo Research). The quantity and integrity of RNAs were analyzed by Nanodrop (Thermo Fisher) and Bioanalyzer (Agilent Technologies). The library was prepared with NEBNext Ultra RNA with Poly-A selection and (NEB) was sequenced on an Illumina Hi-Seq 4000 . The differential gene expression was determined with fold change >1.5 and 2O and 90% ethanol) for 3 days at 37°C. After washing, samples were kept in 1% KOH for 48 h. For long term storage, specimens were transferred into 20, 50 and 80% glycerol solutions and were ultimately maintained in 100% glycerol. The images were captured by a Leica stereomicroscope with a Nikon digital camera.Skeletal staining was performed using a modified Alcian Blue/Alizarin Red staining procedure . BrieflyThe E17.5 fetuses were fixed with 10% formalin followed by 70% ethanol. Specimens were scanned at the University of Texas High-Resolution X-ray CT Facility using the flat panel detector on a Zeiss Xradia 620 Versa. The X-ray source was set to 70 kV and 8.5 W with no filter. A total of 2001 0.1s projections were acquired over ±180 degrees of rotation with no frame averaging. A source-object distance of 18.0 mm and a detector-object distance of 251.7 mm resulted in 9.98-micron resolution. The resulting data were segmented in Avizo software v.2020.2.The experiments were done in triplicate Unless specifically stated otherwise and the data was analyzed by the Standard Deviation (SD) with student t-test for comparing groups. For IHC data, the statistical analysis was performed with 2-way ANOVA, followed by Tukey’s test for multiple comparison (GraphPad Prism9).


Research activity on ceramic/graphene composites and hybrids has increased dramatically in the last decade. In this review, we provide an overview of recent contributions involving ceramics, graphene, and graphene-related materials  with a primary focus on applications. We have adopted a broad scope of the term ceramics, therefore including some applications of GRM with certain metal oxides and cement-based matrices in the review. Applications of ceramic/graphene hybrids and composites cover many different areas, in particular, energy production and storage , energy harvesting, sensors and biosensors, electromagnetic interference shielding, biomaterials, thermal management (heat dissipation and heat conduction functions), engineering components, catalysts, etc. A section on ceramic/GRM composites processed by additive manufacturing methods is included due to their industrial potential and waste reduction capability. All these applications of ceramic/graphene composites and hybrids are listed and mentioned in the present review, ending with the authors’ outlook of those that seem most promising, based on the research efforts carried out in this field. Outcomes about composite materials fabricated by additive manufacturing methods that emphasize applications deserved a separate section because they offer interesting flexibility and potential for novel device development.The number of patents filed in the subject (ceramic + graphene + composites) has experienced an evolution quite similar to that of research articles b but obvThe increasing demand for portable electronic devices and electric vehicles has generated enormous research efforts to improve specific capacity, energy density, cycling performance and safety of batteries used in energy storage systems. One of the recent strategies to address these challenges involves incorporating GRM into battery components for improved electrochemical performance due to graphene´s excellent electrical and thermal conductivities, lightweight, high specific surface area and superior mechanical strength . The pri2, LiFePO4, or LiMnO2, exhibiting theoretical specific capacities in the range 100–300 mA·h·g−1, and transition metal oxides and metal chalcogenides structures in which Li-ion can be intercalated, giving specific capacitance of 100–200 mA·h·g−1 . . 2O3@SiOAs shown in 3O4 composites after oxidation at 600 °C for 2 h. Graphene@magnetic np were proposed to decrease impedance mismatch between the air and the graphene material, and simultaneously increase the magnetic loss. The SiBCN/rGO@Fe3O4 composite processed by PDC technology showed excellent EM properties with minimum RC of −43.8 dB and EAB of 3.4 GHz; after oxidation at 600 °C, the composites exhibited better EM wave absorption, where the RC decreases to −66.2 dB and EAB increases to 3.7 GHz in X-band. Besides, the composites were stable at high temperatures (up to 1100 °C) in both argon and air, owing to the protecting effect of the ceramic matrix around the rGO@Fe3O4 inclusions.Despite the number of current studies on the outstanding EM performance of ceramic/graphene composites, analysis on high-temperature EM properties are scarcer, because of graphene’s poor stability, particularly above 600 °C in oxygen-rich atmospheres. However, there are some recent studies ,200,201,−3) and SE of ~19 dB, with corresponding specific shielding effectiveness (SE divided by density) of 29 dB·cm3·g−1. A SiC protective coating over SiBCN/GF composites slightly increased SE to 20.8 dB, which remained practically unchanged up to 1100 °C (93% SE at RT) [3 (specific SE of 33.8 dB cm3·g−1). The porous structure ensured the penetration of incident EM waves and facilitated dissipation by multiple reflections.Structures with a large specific area and many interfaces, such as foams, multicomponent systems or other hierarchical structures can also enhance SE. Accordingly, some attempts have been done on 3D graphene aerogels and foams due to their high porosity (lightweight), large specific surface area (increases the number of reflections and scatterings) and improved dispersion of graphene sheets, which yields longer pathways for rapid attenuation of EM wave. Moreover, these 3D graphene structures have excellent mechanical characteristics such as compression/recovering capability. Finally, they offer the possibility of anchoring different nanoparticles/nanowires to the graphene surface, for further increases of the impedance matching and interfacial polarization, and to promote additional synergistic loss effects . LightweE at RT) . In a diE at RT) , giving E at RT)  developenw) that displayed an outstanding EM wave absorption ability with an RC of−69.3 dB for 3 wt.% rGO. This high value was attributed to the conductive network, SiCnw stacking faults and rGO defects. Recently, Song et al. [nw composites in which SiCnw (2.29 wt.%) and rGO (0.5 wt.%) overlapped, forming a conductive pathway that significantly enhanced dielectric property and EM absorption characteristic, even at high temperatures and in harsh environments. The minimum RC was −42.02 dB at a thickness of 3.6 mm with a corresponding EAB of 4.2 GHz. Permittivity increased with temperature up to 400 °C because of the enhanced charge carrier density, and decreased above that temperature due to rGO oxidation attaining at 600 °C a minimum RC of −39.13 dB with an EAB that covered the entire X-band. The SiBCN/rGO-SiCnw composite maintained good EMW absorption properties after oxidation at 900 °C, with a minimum RC of −10.41 dB. On the other hand, SiCN/rGO-CNT composites were obtained from a single-source precursor containing chemically bonded GO-CNT hybrids [2O4/rGO nanoparticles by simple hydrothermal and freeze-drying routes. The amount of Co2+ and Fe3+ allowed adjusting the permittivity of the CoFe2O4/rGO hybrids that achieved RC of −38 dB and EAB of 5.9 GHz for a thickness of 2.2 mm. Enhanced absorption performance was achieved for a CoFe2O4/rGO hybrid coated with wave-transparent material lithium–aluminum–silicate (LAS) glass-ceramics by the sol-gel method 3O4@LAS/rGO composites with extraordinary electromagnetic wave absorption performance have been developed [3O4 nanospheres (200 nm) attached by LAS nanoparticles and distributed among the graphene sheets. The EM performance depended on the LAS content, reaching for the Fe3O4/LAS molar ratio of 1/0.2, RC values of −65 dB at 12.4 GHz with a thickness of 2.1 mm and the EAB with RC values less than −10 dB (over 90% EM wave absorption) was up to 4 GHz. Compared to Fe3O4/rGO composites, the addition of LAS significantly enhanced the absorption effect of the material in the X-band and Ku-band (8–18 GHz) and accordingly the thickness of the sample decreased.Regarding graphene-based multi-component systems, Han et al.  reportedg et al.  combined hybrids . For the hybrids  synthesieveloped  from Fe3−3) hierarchically ordered aerogels of rGO wrapped SiC whiskers with high microwave absorption performance were developed , p-nitrophenol and rhodamine B (Fe3O4/rGO/NiO). The large surface area, adsorptive efficiency and numerous catalytic active sites provided by rGO enhanced the degradation of these dyes. Interestingly, all works reported until now have selected GO as the source of graphene-based catalyst, in part attributed to its lower production costs, which are often chemically or thermally reduced to rGO to improve the carrier mobility and electrocatalytic properties.Initial works on ceramic/graphene composite catalysts were published in 2015 by Vinothkannan et al.  and Zhao3O4/rGO  and Fe3O/rGO/NiO  composit2Fe4O9 (BFO), TiO2 or BiVO4/SiO2 has considerably improved those processes. For example, a BFO/5 wt.% rGO composite increased the degradation efficiency of methyl violet solutions [2/graphene composites, Li et al. [2/8 wt.% of rGO composite loaded onto honeycomb ceramic plates via the sol-gel method showed excellent performance for removing clothianidin in pesticide wastewaters. Salem et al. [2/rGO decorated onto mullite rods to recover wastewaters contaminated by the cationic dye. Trinh et al. [4/SiO2/GO nanocomposites by the hydrothermal method, and reported a much higher efficiency for methylene blue removal than the plain ceramics due to the considerably augment of the specific surface area and pore size promoted by GO sheets. There is currently a new line in the catalysis research area that looks for embedding the catalytic species into 3D printed structures because the control over the size, shape and porosity of the structures, as can be seen in The addition of rGO to photocatalytic ceramics like Biolutions , which ai et al.  found thm et al.  developeh et al.  synthesi2/Pd-Ag composites by combining hydrothermal and photo-deposition processes. The degradation of rhodamine B and methylene blue under ultraviolet light irradiation was favored by rGO sheets, which behaved as an electrically conductive pathway for the photogenerated electrons and also as a good adsorbent for organic dye molecules. Similarly, enhanced catalytic performance for the degradation of methyl orange was reported by Wang et al. [2/rGO composite catalyst.Regarding metal-containing catalysts, Khojasteh et al.  producedg et al.  using an2 nanosheets decorated on rGO. The composite containing 20 wt.% of rGO exhibited a superior and more stable electrochemical HER performance than the monolithic material. In fact, the rGO improved the electrical conductivity and accelerated the electron transfer process, which led to smooth and superior kinetics. Zhang et al. [2/MoS2/1 wt.% GO photocatalysts. Hanniet et al. [Ceramic/graphene catalysts have recently been employed in a new application as the electrocatalytic hydrogen evolution reaction (HER). In this way, Mondal et al.  synthesig et al.  obtainedt et al.  developeBioceramics have long been used in bone tissue engineering (BTE) applications ,227. DueOwing to their nanoscale size, excellent mechanical properties, good electrical conductivity, large specific surface area, tunable surface functionalities, photoluminescence properties, high biocompatibility and antibacterial activity, GRM possess enormous potential in biomedicine for BTE, drug and gene delivery, biosensors, bioimaging applications, antibacterial agents, and photothermal therapies ,229,230.−1 might inhibit proliferation of bone marrow mesenchymal stem cells). On the other hand, graphene’s potential toxicity may be decreased through functionalization and compounding with other materials, as the potential to penetrate the cell membrane would be reduced. Many recent studies have been conducted to investigate the potential toxicity of GRM in their interaction with cells and tissues, in vitro and in vivo experiments, that being a critical issue in order to identify suitable candidates for clinical applications, see reviews [Despite the advantages in the bone repair application, some concerns remain about potential toxicity and possible in vivo residues. Current studies demonstrate that toxicity depends on graphene size, being bigger for smaller sizes (<100 nm) than larger ones (>400 nm), and concentration 2·4H2O and (NH4)2HPO4 precursors and a dispersed GO water solution, and a biomimetic approach consisting of two soaking steps in pH-controlled environments: first, a supersaturated SBF solution to promote nuclei formation, and second, a chemically modified solution to encourage the crystallization and growth of apatite nuclei. In the HA/GO nanocomposites processed via sol–gel, spindle-like nanoparticles of HA were strongly bonded to the GO surface by means of Ca2+ ions that attached to the oxygen functional groups on GO. This biocomposite showed enhanced cell viability (hMSC), and induced osteoblastic differentiation without using osteogenic factors. For composites obtained by the biomimetic route, an amorphous calcium phosphate coating formed on GO sheets; these biocomposites also sustained cell viability and proliferation, but the expression of alkaline phosphatase activity was hindered.On the other hand, biomineralized HA nanocrystals/GO composites were produced by two different methods ; namely,The feasibility of rGO hydrogels as artificial barrier membranes for guided bone regeneration was demonstrated by Lu et al. . This mel-lactic-co-glycolic acid)/HA/GO by electrospinning. The role of the polymer component (PLGA) was to provide a uniform and smooth nanofibrous 3D porous substrate with excellent biocompatibility and biodegradation properties, while GO enhanced the tensile strength and conductivity of the substrate, and HA improved the biocompatibility. Zhao et al. [3)2 and K2HPO4 aqueous solution was added to a solution of CS in acetic acid, and mixed with a GO suspension; finally, the CS/nano-HA/GO scaffolds were obtained by treating with an alkaline solution. On the other hand, a 3D porous CS/nano-HA/carbon scaffold was developed by in situ depositing HA nanoparticles on the porous carbon surface and immersion in chitosan solution before freeze-drying [2 and H3PO4 (Ca/P  =  1.66) solutions were added, then the resulting nHAC powder was collected by centrifugation and freeze-dried. This powder was added into the PLGA/GO solution, stirred and ultrasonicated for 4 h before the last freeze-drying. In another wok, the porous carboxymethyl chitosan/nano-HA/GO composite was prepared by chemical crosslinking, lyophilization and afterwards, ultrasonic washing [Organic/inorganic multicomponent hybrids of GO and HA and biopolymers  have also been developed to achieve good cytocompatibility and better hydrophilic and mechanical properties ,247,248.o et al.  prepared washing . Luo et  washing .Usually, graphene needs to undergo some functionalization before using in composites, scaffolds, coatings, membranes or injectable hydrogels. Properties like dispersibility and hydrophilicity can be considerably enhanced by different functional groups, thus improving the bone repair capability and the binding ability to active substances ,251. The5(PO4)2SiO4, previously synthesized by a sol-gel method. In vitro studies demonstrated the deposition of a layer of needle-like amorphous apatite with alkaline phosphatase activity, calcium deposition and osteogenic differentiation ability. The composite showed no toxicity in HUVEC  culture medium and significantly promoted cell proliferation.A recent work by Udduttula et al.  achievedMuch more complex systems that incorporate osteogenesis-inducing drugs, peptides, proteins and anti-bacterial agents have also been developed, aiming at further improving the performance of the scaffold ,255. For3 or Al-doped ZnO are used in thermoelectric-based coolers for electronic devices and batteries, then, although they could be listed in this section, they have been referred to in Many important applications of ceramic materials are linked to thermal properties and heat transfer subjects. Ceramic materials for heat dissipation and thermal management require the assistance of different properties such as electrical insulation and high thermal conductivity. However, ceramics directed to thermal insulation issues generally require very low values of both density and thermal conductivity. In any case, high thermal and mechanical stabilities remain critical attributes. Examples of thermal management use include substrates and heat sinks for light-emitting diodes (LED), computer processors and power electronic devices, as well as heat shields for automotive and aerospace applications. Thermal applications of ceramic/graphene composites also include capsules for infiltration of phase change materials (PCM) used in thermal energy storage systems; in the case of cement-based composites, these uses are reviewed in Within the low thermal conductivity ceramics, we can refer to aerogels and porous materials used as thermal insulation and flame retardants in buildings, motor and aerospace vehicles. In particular, low thermal conductivity materials and coatings have become essential in thermal barrier applications for gas turbines and in thermal protection systems (TPS) of Reusable Launch Vehicles for nose, wings and fin leading edges, where high reentry temperatures (900–1200 °C) and mechanical loads develop. −1⋅K−1, respectively, and remarkable properties like good mechanical strength and high electrical conductivity, which are critical for certain applications. GRM are considered ideal nano-inclusions for tuning the heat transfer performance of ceramics ,257 becaHeat generation in power electronics is a critical matter because a rise in the device temperature can degrade its performance and even cause its failure. In thermal management applications, GRM are either integrated into the device architecture or added as filler. According to recent reviews ,258,259,2O3 foams that display ultralow sheet electrical resistance (0.11 Ω·sq−1) and improved thermal conductivity (8.28 W⋅m−1⋅K−1) [2O3/graphene foam still maintained a κ value of 2.39 W⋅m−1⋅K−1 with a latent heat of 38 J⋅g−1, indicating great potential for heat transfer purposes, especially for heat sink and thermal energy storage applications [2O3 and AlN ceramics, 2O3 showed better adhesion than those obtained by conventional CVD, while delamination was detected for the AlN/graphitic coating structures. The developed structures presented sufficient thermal mass and superior thermal conductivity, 1000 W⋅m−1⋅K−1 for the in-plane and 6 W⋅m−1⋅K−1 for the cross-plane directions, measured for a 6 μm thin layer by the time-domain thermo-reflectance method [2O3 was significantly better than the displayed by AlN substrates, showing 54-fold greater resistor failure time. Besides, there was a delay in the temperature rise that helped prevent thermal shock.Examples of ceramic/graphene materials for thermal management applications, include architectures consisting of a CVD graphene coating on porous Alm−1⋅K−1) . The incications . Howevere method . The the2O3 particles , ~72 times higher than that of the epoxy matrix. Highly efficient thermal conductivity composites that maintain electrical insulation have been developed for TIM application by using aligned graphene or boron nitride sheets . The APCarticles b. The thvity TIM ,267 becavity TIM  describe2O3 nanoparticles on 3D graphene templates, showed very low density, superelastic response, structural robustness, high electrical conductivity, good thermal stability, flame-retardant quality and good thermal insulation (0.05 W⋅m−1⋅K−1).Depending on the graphene ordering within diverse porous structures , hybrids can be used not only for enhancing thermal conduction but also for developing advanced insulating materials . DifferiGraphene coatings have been used to modify carbon fibers (CF) in mullite/CF composites, in order to improve its oxidation resistance and avoid deterioration of the electro-thermal functioning under heating . The proAblative TPS are considered a suitable choice for aerospace applications in those cases where full heat exposure occurs for a short time . Major c2O3-Al2O3-SiO2 system) coatings containing GNP (1 wt.%) on SiC and SiC/CF substrates using a simple and feasible thermal spraying method  inferred non-conventional crack-bridging mechanisms that combined stretching, debonding, sliding and pull-out of the piled graphene layers [4C/GNP (1.5 wt.%) composite, fabricated by SPS, was significantly better than the displayed by two comparable commercial ceramic armors ; actually, the penetration depth for a bullet speed of 818 m·min−1 decreased by ~45% [4C/GNP ceramic armor target plate tested. Despite graphene may obviously contribute to the development of new lightweight and mechanical resistant materials for ballistic applications, works on this subject are rare [Fracture toughness has received specific attention as represents one of the most limiting factors for ceramics application. In particular, significant toughness increases have been reported for low graphene contents when a good filler dispersion within the matrix was guaranteed. Toughening mechanisms have been widely studied and, recently, in-situ observations of crack propagation in ceramic composites  cutting tools containing 0.4 wt.% GNP for continuous dry turning of Inconel 718. This composite showed enhanced mechanical properties and decreased friction between the insert and workpiece on dry reciprocating sliding tests. Based on these results, Inconel 718 was then machined with the composite cutting tool at ultra-high speed using a turning center and dry conditions. The cutting tools exhibited high abrasive wear resistance and better cutting performance than commercial sialon cutting tools, as a direct consequence of the graphene additions.Chen et al.  develope2/0.15 wt.% GO composites for dental implants should be mentioned. The materials were tribologically tested against GCr15 steel bearings using artificial saliva lubrication to simulate the teeth operating conditions. For that purpose, a reciprocating motion with a frequency of 2 Hz was selected, applying a load of 30 N for reproducing chewing forces. Results indicated that GO additions decreased both the friction coefficient and the wear rate. Besides, the composite was biocompatible and promoted cell proliferation. Balazsi et al. [3N4/multilayer graphene (5 wt.%) and SiC/multilayer graphene (2 wt.%) composite pins, respectively, tested against SiC seal rings. In both cases, noticeable reductions of the friction coefficient and wear rate were mutually reported. The water lubrication produced mixed lubrication conditions where the contact pressures decreased and the contact area increased. The water film between the surfaces jointly with the carbon-based tribofilm induced the better tribological response of these composites for seal face components. The tribological performance under isooctane lubrication of different ceramic/graphene composites were chosen to simulate the conditions attained in gasoline direct injection (GDI) engines [3N4/GNP composites containing 20.6 vol.% GNP [Regarding lubricated tribological applications, the work of Zhang et al.  on 3Y-Zri et al.  and Zhani et al.  analyzed engines . It is wol.% GNP  reduced −1) for electrolytic decomposition but significantly enhanced the damping behavior of the YSZ/GNP composite The use of GRM produces very high strength-to-weight ratios in highly porous ceramic/graphene structures, which have unique damping and superelastic responses, and show good prospects for applications in dissipation of impact energy and vibration protection systems, as well as for acoustic insulation . For exa−1 in the ice growth direction) was produced. The local disruption of the graphene network by crack formation and propagation led to a measurable increase (~0.1 mV) of voltage (constant current) in notched bend bars for very small crack propagations (~10 μm). On the other hand, an improvement of the fiber/matrix interfacial bonding of CF composites used as piezoresistive SHM sensors was achieved by growing GO on the surface of CF, these sensors were tested in aerospace, military and civil engineering use [SHM sensors are crucial in detecting stress/strain data in diverse structures to avoid overloads that might lead to breakdown or collapse of the entire structure. Picot at al.  demonstrring use ,291.Cement-based composites (CBC) , the most used materials in construction, display enhanced mechanical properties and damping capability by GRM additions ,293,294.2+ ions. Accordingly, modifications of these fillers  have been proposed to moderate these effects and achieve better mechanical performance. Using any of those modifications, varied mechanical enhancements were reported, for example, increases of compressive (~56%) and flexural strengths (77%) for polycarboxylate-modified GO fillers [The main concerns regarding GO nano-reinforcements for CBC are their possible agglomeration, the reduction of the fluidity of the cement paste due to GO water absorption, and the crosslinking of GO with Ca fillers , a reinf fillers , or impr fillers .Different graphene sources have been recently proposed to avoid some of the problems associated to GO; besides GNP, some authors have tried electrochemically exfoliated (EE) graphene  or multiIn addition to the enhanced mechanical performance, CBC/graphene composites can be used for improving the efficiency of energy consumption in buildings, as well as for SHM self-sensing and de-icing applications ,312,313.Some target application areas according to the review paper by Tian et al.  are seisPisello et al.  investigDimov et al. combined graphene with concrete by mixing water-graphene dispersions with ordinary Portland cement, fine dry sand, and 10 mm coarse aggregate . The higThe enhanced damping capability in CBC by GRM additions ,293,294 Regarding energy consumption efficiency, GRM additions to common phase change materials used in cement have been reported  to increRecently, GO has shown its effectiveness in achieving a cementitious mixture for 3D printing applications. The printable cementitious mixture was fabricated from ordinary Portland cement, industrial waste materials, GO, and chemical additives. GO improved the printability, the fresh mechanical properties and after 28 days curing as well (compression strength of 125 MPa), signaling this route as a viable method for 3D fabrication of a wide range of engineered cementitious materials for civil and construction applications, which is a promising novel manufacturing technology for reducing cost in the use of cement materials .To summarize, GRM can be used to promote construction sustainability with the following potential contributions: less cement consumption, greatly improved mechanical properties, promoting innovative architectural and lighter structural designs, excellent permeability resistance due to low porosity, high early strength that can reduce construction cycle times, energy consumption efficiency and additional interesting functionalities like self-sensing of early damage, damping, de-icing, and even ultra-strong EMI shielding, and fire resistance ability due to the higher thermal conductivity.The outcomes in this topic have received a notable impulse in recent years owing to the notable expansion of 3D printing methods and the noteworthy effects of graphene type inclusions in ceramic composites ,320. Thee was demonstrated owing to the log-pile design of the 3D structure and the reported GNP alignment during printing. Conversely, the compressive strength of the 3D structures decreased with GNP content due to the observed porosity increase. The importance of rod-to-rod contact resistance in determining the electrical conductivity of these structures was noted using modeling tools that were claimed to be applicable to address other properties of the structures [3D SiC/GNP composite structures with variable contents of GNP (5–20 vol.%) were processed by DIW from water-based composite inks, displaying electrical conductivity that increased with GNP additions. Directional response of σructures . −1 and 200 MPa (50 h), respectively [Other authors reported an alternative method for fabricating these composites consisting of DIW of GNP using ethylene glycol butyl ether and ethanol media, followed by CVI with a SiC precursor (methyltrichlorosilane) to form structured composites. As a result, β-SiC grains nucleated between the sheets of the graphene filling the voids and also formed a dense SiC rim on the filaments for the longer CVI times. The electrical conductivity and compressive strength in these composites increased with infiltration time (up to 50 h) and graphene concentration in the inks (25–50 wt.%) reporting maximum values of 3700 S⋅mectively .−1), even at high temperatures, particularly if the GO structure was previously reduced, as well as notable thermal resistance to direct flame and considerable mechanical strength (10 MPa). This kind of 3D composite was tested as supercapacitor electrodes (50.3 F⋅g−1 at 0.06 A⋅g−1) showing large capacity retention after 7000 cycles 3D composites of rGO and amorphous SiCN were also obtained through infiltration; in this case, GO scaffolds were first printed by DIW using aqueous inks and subsequently immersed in an organic-polysilazane liquid polymer, which after crosslinking and pyrolysis (800–1000 °C) formed the amorphous ceramic phase . The relUsing a different perspective, 3D SiOC ceramic structures were printed from preceramic polymers (a methyl silicone resin) with small GO amounts (<1 wt.%) to confer integrity to the structure and reduce contractions of the preceramic polymer during crosslinking and pyrolysis . In othe2O3 with GO (0.5–5 wt.%) additions were prepared by DIW from a mix of colloidal ink of different polyelectrolytes. The structures, treated at 1500 °C in Ar/H2 atmosphere for consolidation and reduction, proved their effectiveness as metal-free catalysts in various Paal-Knorr model reactions to synthesize substituted pyrroles, while maintained their structural integrity and the possibility of regeneration after use [Structured composites of Alfter use .−1 K−1) with respect to the PLA alone (~0.5 Wm−1 K−1). These composites were cryogenic milled and mixed with fumed silica for allowing processing by selective laser sintering into complex shapes with the aim of building enhanced heat dissipation devices for the electronic industry [By adding alumina powders (up to 70 wt.%) and GNP (maximum of 4 wt.%) to biodegradable polylactic acid (PLA) and hot pressing, researchers developed PLA-alumina-graphene composites with enhanced thermal conductivity  xerogel notably enhanced the compressive strength of the rGO scaffolds (in the range 100–400 kPa), inducing a considerable capacity for water absorption as well, thus expecting their potential applications as absorber and pollutant removal [The development of 3D rGO scaffolds grafted with silica  removal , in all On the subject of biomaterials for bone tissue engineering applications, we can mention the use of DIW to create 3D mixed composites of the biodegradable polylactic-co-glycolic acid (PLGA) copolymer with hydroxyapatite powders and GNP (10–90 vol.% referred to HA), with maximum polymer contents of 10–40 vol.%, which solidify rapidly by the use of a convenient mixture of three solvents. These scaffolds were used for in vitro studies through mesenchymal stem cell seeding, reporting cell proliferation, although a clear neurogenic effect assumed by the conducting character of the scaffolds was not observed . In a di®) with different amounts of rGO  by DIW was reported using water as a solvent and carboxymethyl cellulose as a viscosity modifier, results indicated that optimal mechanical enhancement was achieved for the 1 vol.% rGO composite sintered at 500 °C [2O3, looking in this case for a magnetic functionality usable in hyperthermia therapy. Accordingly, β-TCP scaffolds were DIW using aqueous mixtures with polyvinyl alcohol, which were sintered at 1100 °C once conveniently dried. The scaffolds were subsequently immersed in Fe2O3-GO and GO solutions, repeating this process several times to achieve a layered Fe2O3-GO/GO microstructure on the β-TCP filaments. Results indicated that the magnetothermal effect induced in the scaffolds actually killed tumor cells and stimulated osteointegration as well [The printing of bioactive glass composition  and GO (contents from 5–20 vol.%) plus water with no other additives. The GO addition definitively made the geopolymer printable by DIW methods. The printed structures needed to set at a fixed temperature (5 °C) and humidity conditions prior to sintering at temperatures of 1000 °C, rendering conductive robust structures . A similNanoclay particles of laponite and GO sheets have been used to enhance printability and photothermal activity of the responsive hydrogel precursor N-isopropylacrylamide (NIPAAm). A small amount of a photoinitiator was also added to the mixture. The suspensions were kept for one day in dark sealed containers before been ready for DIW. Researchers achieved multi-responsive hydrogels (to heat or light exposures), and predictable undulating shapes in the composites by using two dispensing pumps with slightly different compositions. Combinations of these composite hydrogels were employed to fabricate a microfluidic system feasible for biological and chemical uses .2 substrate (50 °C) to favor capillary bridging. The films were treated at 350 °C to nucleate ZnO and form multiple ZnO/GNP junctions; after testing for ultraviolet light (340 nm) detection, they proved better response than alike composites processed by other methods [3 detection with a reported enhanced overall performance compared to other sensors, with claimed repeatability and scalability based on the CMOS platform used [3-graphene hybrids alleging the plausible application to other metal oxide sensing materials.Several studies have recently been published on printed ZnO-graphene hybrids. We can mention first the inkjet printing of a mixture of ZnO powders and graphene flakes, using N-methyl-pyrrolidone (NMP) as a solvent, on micro-ridged PDMS substrate to achieve a highly stretchable and flexible strain sensor suitable for body sensing. The highest sensitivity for different strain levels was reported for the 1graphene:0.5ZnO ratio . In a di methods . On the orm used . The samnp/graphene system, researchers have fabricated a porous photodetector film by inkjet printing taking advantage of the different volatility of co-solvents and the change in surface tension by the graphene presence to create controlled microporosity in the films. The Ilight/Idark ratio of the composite films although small it proved larger than that of the pure ZnO film, and increased with porosity as well [Within the same ZnO  as well . 2O3-GNP were extrusion printed using a mixture of polymers, solvents and some water, this mixture settled at RT. The scaffolds were intended for applications in electronic devices, which researchers proved building different gadgets such as a magnet-driven toy car, a magnetic switch, or an electromagnetic interference shielding grit [Feing grit .3O4 nanosheets have been mixed with rGO to improve the electric conductivity of the oxide. The composites were achieved by reaction and precipitation of Mn salt and GO mixtures, and subsequent hydrothermal reduction. The composites showed higher specific capacitance than the counterparts and offered the possibility of been shaped by DIW methods [In the subject of electronic energy storage, efforts have been done for increasing the current density of supercapacitors; for that purpose, Mn methods . For achieving high-performance electrochemical devices some researchers have designed a hybrid system of a bimetallic nickel–cobalt sulfide (Ni–Co–S) and graphene with an architected structure achieved by DIW, aiming at increasing both, the accessibility to active redox sites and the pathways for the ion/electron transfer. To achieve printability characteristics, the precursors (NiCo synthesis product/GO) were mixed with sodium alginate to gain printability. The structures after freeze-drying, reduction and sulfurization, showed a highly interconnected microstructure and large capacity retention. As proof of concept a fully printed device for electrochemical energy storage was assembled (both electrodes) .4Ti5O12, LTO) and lithium iron phosphate , respectively. Both electrodes were consecutively printed by DIW on a glass substrate, freeze-dried and annealed at 600 °C in Ar/H2 for GO reduction, and accordingly tested in a planar battery electrochemical cell demonstrating high stability. The possibility of a miniaturized design of the cells was demonstrated in In the field of Li-ion batteries, it should be recognized the achievement of an interdigitated battery cell by printing of the anode and cathode using mixtures of GO with lithium titanium oxide (Li2/GO anode intended to accommodate the larger Na ions and larger volumes changes during the charge/discharge cycles. The method chosen was inkjet printing of a mixed ink of GO and a MoS2 precursor in combination with the freezing of the printed drops by cooling at −30 °C the substrate, later freeze-drying and annealing at 600 °C in Ar/H2 for GO reduction and preserving the porous nature. The electrochemical characterization indicated the potential of this 3D printed MoS2/rGO porous electrode for Na ion batteries [Regarding the future Na ion batteries, an attempt has been reported on the printing of a porous MoSatteries .Ceramic/graphene composites and hybrids are attractive alternatives for the fabrication of more efficient, lighter and compact batteries. Product commercialization will be a reality once relevant issues for large-scale production, i.e., facile and standardized synthesis routes, control of graphene agglomeration and reproducibility of homogeneous components, are solved. Equally, supercapacitor fabrication is one of the fields in which the whole potential of GRM composites can be successfully exploited in the near term. Further efforts are needed for application in electrodes for fuel cells to gain more knowledge on long operation times. In the case of solar cells, the actual development is at a research stage for a better understanding of the effects on charge transport mechanisms.Ceramic/graphene materials have shown good responses in energy harvesting but need to be combined with specific product designs to maximize efficiency. Nano and micro-generators are clean novel technologies but still in an early development stage, hence, more efforts will be necessary for the following years. These materials will be relevant for future portable and wearable devices.Graphene-based compounds and hybrids have clearly demonstrated improved overall performance as electrochemical sensors and biosensors for the detection of molecules biomolecules, bacteria and viruses, which has been the impetus for extensive research in this area. The benefits related to miniaturization and portability are also important goals. Control over manufacturing methods, scalability, and reliability are issues that need to be solved. The development of laboratory-scale detection devices has proven its feasibility and at the moment, market product development is a closer challenge, driven by the current global health juncture and also by crucial environmental issues.Despite the excellent results of ceramic/graphene composites in biomedicine, in-vivo experiments on the potential toxicity and possible residues are still required. Complex systems, in which osteogenesis-inducing drugs, peptides, proteins, and anti-bacterial agents are incorporated, emerge with great potential in the near future. Regarding engineering applications, we can mention the excellent tribological results attained at the lab scale for ceramic/graphene composites that will allow short-term testing in a number of real applications, particularly in cutting and machining operations, engine components, seal face parts and dental implants. The favorable effects of graphene on the short-crack and long-crack toughness, elasticity, strength and dynamic mechanical performance of ceramic materials opens an important area of scarcely explored applications, like impact and ballistic protection, vibration protection, damping and stress/strain self-monitoring. Research in this field is currently focused on cementitious materials with the first graphene reinforced concrete commercial product just announced. An increased effort is expected in the near future for high added-value applications of high-temperature ceramics. GRM has proved to be ideal nanofillers for tuning the heat transfer performance of ceramics. Investigation on the thermal performance of highly porous hierarchical multi-material structures at working conditions, including modeling, will be necessary for the applications of these composites in thermal management.EMI shielding is one of the most promising applications of ceramic/graphene composites as EMI pollution is an unsolved relevant issue for devices working at high temperatures and harsh environments. Targets in this subject include the development of hierarchical multicomponent structures using PDC and sol-gel precursor technologies. The good catalytic performance of both metal-free and metal-containing ceramic/graphene composites would favor new developments for efficient removal of larger number of chemical contaminants and also lead to a higher yield in hydrogen production in the next years.The outlook for additive manufacturing methods in relation to the industrial applications of ceramic/graphene composites is brilliant as they offer advantages such as precise computerized designs, miniaturization and multi-material 3D structures. Reductions of waste and toxic materials are opportunities of additive manufacturing methods in addition to the advantages of improved flexibility and integration, compared to other technologies. Particularly promising are the applications as bio-materials scaffolds, supercapacitors, batteries and sensors. Summarizing the application prospects for ceramic/graphene composites show varying degrees of development, as they include many different areas, some of them look quite real but future developments are very dependent on the availability of standardized GRM sources, the fair control over manufacturing methods, scalability and reliability, but also on external factors such as societal challenges, environmental and health issues.


Interpreters can either interpret from the first language (L1) to the second language (L), or in the other direction. Understanding translation and interpreting as a direction-dependent process contributes to a wider and more critical view regarding the role of both languages in the process, as well as the identity, perspectives, and preferences of translators. The effect of directionality primarily weighs on stimulus and individual factors. This study explores the impact of directionality on the performance of trainee interpreters by examining four critical aspects of quality in target speeches, namely: speech rate, information completeness, delivery, and quality of expression. We observed an advantage for L2-L1 over L1-L2 interpreting in the form of interpreting quality  but not in content . These effects of interpreting directionality suggest an important role of L2 proficiency in interpreting. Moreover, L1-L2 interpreting is cognitively demanding compared to L2-L1 interpreting for trainee interpreters. This research sheds light on the cognitive mechanisms of interpreting in different directions and provides pedagogical recommendations for training interpreters. Interpreting can differ in its directionality: it can be done from the interpreter’s first language (L1) into their second language (L2) or the other way around  which is a cognitively demanding multitask involving different cognitive processes . Therefore, it is of paramount difficulty to identify how directionality may serve as a modulator in CI. Previous studies found that directionality has some impact on lexical translation with an asymmetry effect, where L2-L1 translation or interpreting is more fluent than the reverse direction . The traMost CI or SI studies that go beyond lexical translation are confined to certain aspects of interpreters’ performance or interpreting quality, such as fluency , accuracvia their L1 equivalents, especially, in bilinguals with lower L2 proficiency. As a result of these asymmetries in word-concept relationships between L1 and L2, RHM predicts that L2-L1 translation or interpreting should be faster than that of L1-L2 at the lexical level  of bilingual language processing  proposesal level . RHM alsal level . Among tal level , or tranal level . Furtheral level . This inal level . As has As a window to biligual language processing, lexical translation (or word translation) tasks have been administered in different control settings to investigate the directionality effect on bilinguals and interpreters . Being tMany studies have confirmed that the asymmetry effect appears to decrease when the level of L2 proficiency increases, regardless of other factors in L1-L2 or L2-L1 translation or interpreting . In thisRegarding the investigations on the category of individual-level factors , a few studies have found evidence in support of the RHM hypothesis that the effect of directionality appears among unbalanced bilinguals or L2 learners. For instance, unbalanced bilinguals appear to have developed asymmetric relationships between category names . Poarch The asymmetry is also supported by behavioral and neuroscientific observations. Behaviorally, Translation and interpreting studies have explored the directionality effect under different settings, including regular translation practices , and intWith the aid of pen recording and eye-tracking techniques, Among novice interpreters, a number of studies on directionality effects found support for an L2-L1 advantage in interpreting. With regard to the language pair of Chinese (L1) and English (L2), participants of such studies include both professional interpreters  and studIn terms of individual factors, studies have found that the difference in professional interpreters’ performance appears to be the result of a combination of factors rather than just directionality, such as discourse structures and audience expectations . HoweverIn summary, regarding the impact of the individual-level factors on directionality, the studies have reported conflicting results. It remains unclear whether interpreters perform differently in different interpreting directions and to what extent directionality interacts with other factors including language proficiency, working memory, and translation expertise to make an impact on the interpreting performance.When considering stimuli-related variables, as per RHM and relevant studies testing the RHM hypothesis, word translation is found to be modulated by directionality; these stimuli-related effects may disappear as L2 proficiency increases, suggesting that the conceptual level has a role in both directions, while the lexical routes appear to operate asymmetrically  and 4 , as illustrated in Two independent raters separately scored all the enhanced CI quality protocols listed in The participants are 66 undergraduate and postgraduate students from translation and interpreting programs of various universities in Southwest China . All participants were native Chinese speakers who learned English through formal education. Their ages ranged from 20 to 26years. Notably, they were right-handed and none of them had neurological or psychiatric antecedents. The materials are eight recordings (three from L1-L2 and five from L2-L1) in the second round of the nationwide interpreting competition. Each participant was required to perform CI in two directions. The first task is from L2 to L1 and participants were randomly assigned a passage, then followed by a L1 to L2 task with a passage which is also randomly assigned from the database. The distribution of passages is given in They were transcribed by the authors and the minimal instances that required editing were resolved through consensus between the first and the second authors. Transcriptions were saved as DOC files for further processing and analysis. Details of the eight recordings are provided in Participants remotely accessed the recordings through their computers using a headset. They could listen to the recordings once only and then required to interpret the task once the recording finished. The first was an L2-L1 CI task. Participants were required to listen to an English passage randomly assigned from the five topics. There was no stop in the recording and students were allowed to freely take notes. Afterwards, the participants were asked to interpret the English passage into Chinese right after the recording stops. The platform started to record participants’ voice once the source recording stopped. Recording of the interpreting output would last 1.2 times of the original recording before it stopped. The L2-L1 task was then administered upon completion of the L1-L2 task, which was also randomly assigned to participants from the three topics mentioned above. The same procedure was repeated as in task 1. Recordings which contain students’ interpreting output that fall within the allowed time window were regarded as eligible in the contest.Recordings were first automatically transcribed through iFlytek, a software reported to have 97.5% accuracy in English recognition . SubsequFirst, delivery was measured in terms of quantifying pauses and disfluencies. Based on the model proposed by In addition, the quality of expression in terms of grammatical, syntactic, and lexical errors was measured . In linet-tests were used to compare the two directions of interpreting. Cohen’s d was used to indicate the effect sizes and classified as small (d<0.2), medium (d<0.5), and large (d<0.8). As described in section “Directionality Effect in Translation and Interpreting Activities,” ten metrics were measured in four categories, i.e., speech rate, information completeness, delivery, and quality of expression. Their descriptive statistics are detailed in Experimental data and analytical scripts are publicly available on Open Science Framework.The speech rate in the L2-L1 task was significantly faster than that in the L1-L2 task . No effect of directionality was found regarding information completeness . There was an effect of directionality in three metrics of delivery, namely false starts , repetition  and slips of tongue . The directionality effect was also found in Quality of Expression in all three metrics, namely, false collocation , Missing IC , and Redundancy . Overall, we can see that directionality effect holds true in the majority of metrics used in this study.This work evaluated the impact of directionality on the CI performance of trainee interpreters, with L1 in Chinese and L2 in English. Based on the enhanced CI quality scale of For speech rate, we found a significant difference between the two interpreting directions, with the rate of L2-L1 interpreting faster than that of L1-L2. This result echoed the findings of Regarding information completeness of CI, information retention often requires multitasking, including listening comprehension, high-order cognitive processing, and linguistic reformulation skills . Since wAs for delivery, significant differences were found between the two directions. In this category, we captured the frequency of filled and unfilled pauses together with disfluency features ; notably, each has been included in several quality interpretation assessment scales as critical values in delivery . AccordiAs a major metric in delivery, pauses (filled and unfilled) have been used in various studies to evaluate the effect of directionality and among different subjects (novice or expert). Our findings of no significant differences in both filled and unfilled pauses between the two interpreting directions are consistent with the findings reported in previous studies. For example, Similarly, we observed the impact of directionality in the category of quality of expression. To our knowledge, this is the first study exploring whether the quality of expression in CI is susceptible to the directionality effect. This category, which consists of three metrics, i.e., false collocation, missing independent clause, and redundancy, primarily reflects the manner in which grammatical mistakes occur in interpreting output. The metrics used in this category have been widely employed to assess the interpreting performance in various contexts . Our finTaking together the significant effects of directionality on delivery and quality of expression, the CI performance of trainee interpreters was better in the L2-L1 than in L1-L2 task. Studies have attributed several factors to the impact of directionality, including market and speech characteristics , interprDelivery and quality of expression tend to gauge how target language reformulation is influenced by directionality. Interpreting is a complex cognitive activity involving an array of interwined sub-cognitive tasks. Notably, it is impossible to link any sub-tasks to the final product of interpreting. In bilingual processing, it is generally acknowledged that one language must be inhabited when producing the other. The act of interpreting requires constant and repeated activation as well as inhabitation of one language or the other. Thus, the cognitive mechanism underlying delivery and quality of expression is more inclined towards L2 production, but likely to be inhibited by L1 among unbalanced bilinguals . Our stuvia an online interpreting platform. Such a setting, despite its near-naturalness in terms of environmental setup and interpreting materials, can give rise to some issues that might confound the study results. For example, while participants were allowed to take notes during interpreting, such notes were inaccessible to the researchers. We are fully aware that note-taking can be a key modulator in interpreters’ performances. To what extent note-taking can affect the directionality effect is worthy of future investigations In addition, the language pair used in the current study (L1: Chinese and L2: English) consists of two languages that are genetically different from each other. Results of the current study indicate that L2-L1 advantage appeared with novice interpreters in conducting CI tasks in speech rate, quality of expression, and some delivery metrics including false starts, repetition and slips of tongue. This is in line with Our study is not without limitations. First, our data were derived from interpreting tasks conducted remotely The findings have great pedagogical implications. The notion that translating from one’s mother tongue into a foreign language does not have much value is deeply rooted in the western world, as evidenced by the mainstream practice by international organizations which accept only L2-L1 translation . In direIn conclusion, we explored how the performance of student interpreters is influenced by directionality using naturalistic data from an interpreting contest. Our research has provided insights from the perspective of CI between Chinese and English, two languages that are typologically different from each other. Our findings are broadly consistent with previous findings based on different language pairs, and with previous findings based on participants of different language proficiency and professional experience . We havehttps://osf.io/su8zy/.The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found at: The studies involving human participants were reviewed and approved by University of Electronic Science and Technology of China. The patients/participants provided their written informed consent to participate in this study.IC: conceptualization, methodology, formal analysis, investigation, resources, writing – original draft, and writing – review and editing. KL: writing – original draft and writing – review and editing. NZ: writing – review and editing and formal analysis. All authors contributed to the article and approved the submitted version.This work was supported by the Fundamental Research Funds for the Central Universities, UESTC (grant no.: ZYGX2019J140).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.