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Ti2AlC, a MAX phase ceramic, has an attractive self-healing ability to restore performance via the oxidation-induced crack healing mechanism upon healing at high temperatures in air (high oxygen partial pressures). However, such healing ability to repair damages in vacuum or low oxygen partial pressure conditions remains unknown. Here, we report on the self-healing behavior of Ti2AlC at a low oxygen partial pressure of about 1 Pa. The experimental results showed that the strength recovery depends on both healing temperature and time. After healing at 1400 °C for 1–4 h, the healed samples exhibited the recovered strengths even exceeding the original strength of 375 MPa. The maximum recovered strength of ∼422 MPa was achieved in the healed Ti2AlC sample after healing at 1400 °C for 4 h, about 13% higher than the original strength. Damages were healed by the formed TiCx from the decomposition of Ti2AlC. The decomposition-induced crack healing as a new mechanism in the low oxygen partial pressure condition was disclosed for the MAX ceramics. The present study illustrates that key components made of Ti2AlC can prolong their service life and keep their reliability during use at high temperatures in low oxygen partial pressures.

Research on consumer in-store shopping behavior does not account for the existence of different types of display locations (e.g. storefront, store rear, secondary, front end cap, rear end cap, and shelf displays). This article focuses on accounting for and understanding the impact of various displays on consumer purchase behavior based on the Stimulus-Organism-Response (SOR) theory. Specifically, we study how displays closer to and farther from the main location of the focal category influence consumer purchase behavior. Furthermore, within the different types of displays we investigate the impact of specific types of displays on consumer's category purchase and brand choice and the moderating role of price and discounts. A hierarchical Bayesian model is estimated using scanner panel data for a large U.S. grocery chain that contains unique information on the number of product facings at multiple display locations within a store. We find that displays closer to the focal category have a larger impact, with front end cap displays having the largest impact on category purchase and shelf displays having the largest impact on brand choice. We also demonstrate the synergistic impact of price and discounts in enhancing the impact of displays on consumer purchase behavior and brand choice. Equipped with these findings we propose a display allocation optimization that results in an average increase in revenue of about 11.15% and a strategy to distribute displays across all locations in the store rather than letting one location dominate.

TiO2 semiconductor photocatalysis is an effective technology for the treatment of wastewater containing organic dye pollutants, which has been received extensive focus. However, the problems in the recovery and reutilization process impede the large-scale applications of particulate photocatalytic materials. Herein, a macro sized hydrogel bead loaded with nano TiO2 powder was successfully prepared by taking advantage of the cross-linking and gel property of alginate salt, which could form egg-box structure naturally when Na+ ions in sodium alginate (SA) were replaced by divalent ions such as Cu2+, Co2+, and Sr2+ ions. The photocatalytic degradation rate of methyl orange (MO) solution in the presence of the hydrogel beads reaches 99% within 60 min under the ultraviolet light irradiation, which is competitive with that of TiO2 nano powder. Furthermore, the hydrogel beads prepared by this strategy maintain over 95% photocatalytic degradation rate after 10 cycles of degradation process. The results indicate that the network structure of alginate could immobilize and disperse TiO2 particle effectively, and it is readily for the spherical beads to contact and harvest the light, making the alginate beads have excellent photocatalytic functions. Also, the alginate based beads integrate good performance with high stability and excellent recyclability perfectly.

Among the current five Variants of Concern, infections caused by the SARS-CoV-2 B.1.617.2 (Delta) variant are often associated with the greatest severity. Despite recent advances on the molecular basis of elevated pathogenicity using recombinant proteins, architecture of intact Delta virions remains veiled. Moreover, molecular evidences for the detailed mechanism of S-mediated membrane fusion are missing. Here we reported the in situ structure and distribution of S on the authentic Delta variant, and discovered invagination in the distinctive Delta architecture. We also captured fusion snapshots from the virus-virus fusion events, provided structural evidences for Delta’s attenuated dependency on cellular factors for fusion activation, and proposed a model of S-mediated membrane fusion. Site-specific glycan analysis revealed increased oligomannose-type glycosylation of native Delta S over that of the Wuhan-Hu-1 S. Together, these results disclose distinctive factors of Delta being the most virulent SARS-CoV-2 variant.In BriefCryo-ET of intact SARS-CoV-2 Delta variant revealed its distinctive architecture and captured snapshots of its membrane fusion in action.

Per- and polyfluoroalkyl substances (PFASs) have attracted worldwide attention due to their high stability, refractory degradation, and bioaccumulation. In this study, 17 PFASs in water, sediment, and fish in the Dongjiang River Basin in southern China were investigated using high-performance liquid chromatography-mass spectrometry. Total PFASs concentrations ranged from 20.83 to 372.8 ng/L in water, from 1.050 to 3.050 ng/g in sediments, and from 12.28 to 117.4 ng/g in fish. Among six species of fish, Oreochromis mossambicus (mean: 68.55 ng/g) had the highest concentration of PFASs, while Tilapia zillii (36.90 ng/g) had the lowest concentration. Perfluorooctanoic acid (PFOA) predominates in water and sediments, while perfluorooctanesulfonic acid (PFOS) predominates in fish. Long-chain perfluorocarboxylates (PFCAs) and perfluorosulfonates (PFSAs) showed higher bioaccumulation, and the field-sourced sediment-water partition coefficients (Kd) and bioaccumulation factors (BAFs) of PFASs increased with the length of perfluorocarbon chains. PFASs concentration in the lower reaches (urban area) of the Dongjiang River is higher than that in the upper and middle reaches (rural area). The calculated hazard ratio (HR) of PFOS and PFOA levels in fish in the Dongjiang River Basin were far less than 1, hence the potential risk to human health was limited.

Novel MoAlB composites reinforced with 5–15 vol% SiC have been firstly prepared and characterized in the present study. The SiC reinforcement is stable with MoAlB at a sintering temperature of 1200 °C in Ar. The 5 vol% SiC/MoAlB composite exhibited improved mechanical properties and enhanced oxidation resistance. A flexural strength of 380 MPa and a Vickers hardness of 12.7 GPa were achieved and increased by 24% and 51%, respectively, as compared with those for MoAlB, indicating the enhanced strengthening effect of SiC. Cyclic oxidation tests at 1200 and 1300 °C for 10 h in air showed that the 5 vol% SiC/MoAlB composite has better oxidation resistance than MoAlB due to the formation of a dense and continuous scale composed of Al2O3 and SiO2, which prevents the oxygen inward diffusion and the evaporation of oxides. We expect that the general strategy of second phase reinforcing for materials will help to widen the applications of MoAlB composites.

Entrepreneurship is a key concept to understand the rapid development of China’s economy since the reform and opening-up. It is related to the revitalization of the Chinese nation. Formulating effective entrepreneurial policies and measures, carrying out entrepreneurship education, and promoting entrepreneurial actions are important issues that government agencies, educational institutions, and the society at all levels are paying attention to. The key lies in the insight into the psychological cognitive mechanism and motivation source of entrepreneurs in starting a business. Upon reviewing previous studies, this article believes that entrepreneurial self-efficacy and entrepreneurial intentions are the key concepts and entry points connecting entrepreneurial characteristics, entrepreneurial behavior, and cognitive research. This study explores the relationship between entrepreneurial self-efficacy and entrepreneurial intention from five dimensions: entrepreneurial planning efficacy, entrepreneurial resource acquisition, relationship coordination efficacy, risk-taking efficacy, as well as innovation and reform efficacy. Suggestions and strategies have been proposed in this article to integrate the entrepreneurial ecology of universities, society and the government, reform the entrepreneurial education model, as well as improve the entrepreneurial willingness of college students.

We aimed to identify any differences in the clinical characteristics of patients treated in Zhoushan Hospital and Wuhan Fourth Hospital, Gutian campus to provide insights into measures to better control the coronavirus disease 2019 (COVID-19) pandemic and treat COVID-19 patients.All cases included in this retrospective study from January 10, 2020 to March 15, 2020 were confirmed by laboratory detection of SARS-CoV-2. Data of epidemiological characteristics, clinical characteristics, laboratory results, radiological findings, treatments, and outcomes were obtained from electronic medical records and compared between the patient groups.A correlation analysis was performed to detect correlations between the serum C-reactive protein (CRP) level and other laboratory findings. COVID-19 patients treated in Wuhan more commonly had fever and shortness of breath, and less commonly had headache compared to those treated in Zhoushan (P=0.002, 0.039, and 0.015, respectively). The period from illness onset to hospitalization in Wuhan was 11.7±7.2 days, which was longer than that in Zhoushan (4.2±3.7 days; P=0.002), whereas the period from illness onset to shortness of breath in Wuhan was 5.4±5.0 days, which was shorter than that in Zhoushan (14.0±5.6 days; P=0.020). Computed tomography scans showed linear opacities, reticulation, and patchy shadows more commonly in cases treated in Wuhan (P=0.016, 0.013, and 0.008, respectively). The mean CRP level in Zhoushan patients was lower than that in Wuhan patients (P0.001), and the CRP level was correlated with several laboratory findings related to the immune response.COVID-19 patients treated at Wuhan Fourth Hospital, Gutian campus had more severe symptoms than those treated at Zhoushan Hospital. Earlier in-hospital treatment, as conducted in Zhoushan, may be beneficial in reducing the severity of illness in COVID-19 patients. Additionally, the correlations between the CRP level and indicators of immune function in COVID-19 patients warrant further investigation.

Novel and highly effective electromagnetic interference (EMI) shielding materials are desirable to attenuate unwanted electromagnetic radiation or interference produced by electrical communication devices. Here, functional Ti3C2Tx@Ni particles with a core@shell and sandwich like structure were fabricated using the facile electroless plating technique. The core@shell structured Ti3C2Tx@Ni consists of a Ti3C2Tx core and a Ni shell. In the core, thin Ni layers are sandwiched in between Ti3C2Tx flakes. EMI shielding effectiveness (SE) values of Ti3C2Tx@Ni/wax composites increased with increasing Ti3C2Tx@Ni content. The average EMI SE value of 60 wt% Ti3C2Tx@Ni/wax composite was 43.12 dB, increased by 73% as compared with 24.93 dB for the same content of pristine Ti3C2Tx in wax in the frequency range 2–18 GHz. An average EMI SE of 74.14 dB was achieved in the 80 wt% Ti3C2Tx@Ni/wax. The enhanced EMI shielding performance should be ascribed to the synergic effect of the absorption loss of the Ti3C2Tx core and the magnetic loss of the Ni shell and the inner Ni layers.

MAX phases (Ti3SiC2, Ti3AlC2, V2AlC, Ti4AlN3, etc.) are layered ternary carbides/nitrides, which are generally processed and researched as structure ceramics. Selectively removing A layer from MAX phases, MXenes (Ti3C2, V2C, Mo2C, etc.) with two-dimensional (2D) structure can be prepared. The MXenes are electrically conductive and hydrophilic, which are promising as functional materials in many areas. This article reviews the milestones and the latest progress in the research of MAX phases and MXenes, from the perspective of ceramic science. Especially, this article focuses on the conversion from MAX phases to MXenes. First, we summarize the microstructure, preparation, properties, and applications of MAX phases. Among the various properties, the crack healing properties of MAX phase are highlighted. Thereafter, the critical issues on MXene research, including the preparation process, microstructure, MXene composites, and application of MXenes, are reviewed. Among the various applications, this review focuses on two selected applications: energy storage and electromagnetic interference shielding. Moreover, new research directions and future trends on MAX phases and MXenes are also discussed.

Ti3C2Tx has microwave absorption (MA) properties due to its dielectric loss, but the absence of magnetic loss capability of pure Ti3C2Tx causes unmatched impedance and unsatisfied MA performance. Modification of Ti3C2Tx with magnetic particles is an effective way to introduce the magnetic loss mechanism. However, these modified Ti3C2Tx particles have higher density and require complicated fabrication processes, restricting the industrial production and functional applications. Here, a low-temperature and simple method of radio-frequency N2 plasma treatment was adopted to modify Ti3C2Tx with N. More interestingly, the N-doped Ti3C2Tx flakes demonstrated magnetic properties and thus exhibited drastically enhanced MA properties. The minimum reflection loss (RLmin) of -59.20 dB at 10.56 GHz was achieved in N-doped Ti3C2Tx products after only 3 min of plasma treatment, remarkably higher than RLmin of -11.07 dB at 7.92 GHz for the pristine Ti3C2Tx. The main mechanism is due to the combination of dielectric loss, magnetic loss, and the good impedance matching in the N-doped Ti3C2Tx. Further prolonging the nitriding time induces much desorption of -F and the formation of TiO2, thus deteriorating the impedance matching and the MA properties.

Nonalcoholic fatty liver disease (NAFLD) has emerged as a public health concern. To date, the mechanism of NAFLD progression remains unclear, and pharmacological treatment options are scarce. Traditional animal NAFLD models are limited in helping address these problems due to interspecies differences. Liver chips are promising for modeling NAFLD. However, pre-existing liver chips cannot reproduce complex physicochemical microenvironments of the liver effectively; thus, NAFLD modeling based on these chips is incomplete. Herein, we develop a biomimetic liver lobule chip (LC) and then establish a more accurate on-chip NAFLD model. The self-developed LC achieves dual blood supply through the designed hepatic portal vein and hepatic artery and the microtissue cultured on the LC forms multiple structures similar to in vivo liver. Based on the LC, NAFLD is modeled. Steatosis is successfully induced and more importantly, changing lipid zonation in a liver lobule with the progression of NAFLD is demonstrated for the first time on a microfluidic chip. In addition, the application of the induced NAFLD model has been preliminarily demonstrated in the prevention and reversibility of promising drugs. This study provides a promising platform to understand NAFLD progression and identify drugs for treating NAFLD. Statement of significance Liver chips are promising for modeling nonalcoholic fatty liver disease. However, on-chip replicating liver physicochemical microenvironments is still a challenge. Herein, we developed a liver lobule chip with dual blood supply, achieving self-organized liver microtissue that is similar to in vivo tissue. Based on the chip, we successfully modeled NAFLD under physiologically differentiated nutrient supplies. For the first time, the changing lipid zonation in a single liver lobule with the early-stage progression of NAFLD was demonstrated on a liver chip. This study provides a promising platform for modeling liver-related diseases.

AIMS: To explore the contagiousness and new SARS-CoV-2 mutations in pediatric COVID-19. METHODS: This cohort study enrolled all pediatric patients admitted to 8 hospitals in Zhejiang Province of China between 21 January and 29 February 2020, their family members and close-contact classmates. Epidemiological, demographic, clinical and laboratory data were collected. Bioinformatics was used to analyze the features of SARS-CoV-2. Individuals were divided into 3 groups by the first-generation case: Groups 1 (unclear), 2 (adult), and 3 (child). The secondary attack rate (SAR) and R0 were compared among the groups. RESULTS: The infection rate among 211 individuals was 64% (135/211). The SAR in Groups 2 and 3 was 71% (73/103) and 3% (1/30), respectively; the median R0 in Groups 2 and 3 was 2 (range: 1-8) and 0 (range: 0-1), respectively. Compared with adult cases, the SAR and R0 of pediatric cases were significantly lower (p

COVID-19 has emerged as a global pandemic, challenging the world’s economic and health systems. Human oral microbiota comprises the second largest microbial community after the gut microbiota and is closely related to respiratory tract infections; however, oral microbiomes of patients who have recovered from COVID-19 have not yet been thoroughly studied. Herein, we compared the oral bacterial and fungal microbiota after clearance of SARS-CoV-2 in 23 COVID-19 recovered patients to those of 29 healthy individuals. Our results showed that both bacterial and fungal diversity were nearly normalized in recovered patients. However, the relative abundance of some specific bacteria and fungi, primarily opportunistic pathogens, decreased in recovered patients (RPs), while the abundance of butyrate-producing organisms increased in these patients. Moreover, these differences were still present for some organisms at 12 months after recovery, indicating the need for long-term monitoring of COVID-19 patients after virus clearance.

Emergence of various circulating SARS-CoV-2 variants of concern (VOCs) promotes the identification of pan-sarbecovirus vaccines and broadly neutralizing antibodies (bNAbs). Here, to characterize monoclonal antibodies cross-reactive against both SARS-CoV-1 and SARS-CoV-2 and to search the criterion for bNAbs against all emerging SARS-CoV-2, we isolated several SARS-CoV-1-cross-reactive monoclonal antibodies (mAbs) from a wildtype SARS-CoV-2 convalescent donor. These antibodies showed broad binding capacity and cross-neutralizing potency against various SARS-CoV-2 VOCs, including B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma) and B.1.617.2 (Delta), but failed to efficiently neutralize Omicron variant and its sublineages. Structural analysis revealed how Omicron sublineages, but not other VOCs, efficiently evade an antibody family cross-reactive against SARS-CoV-1 through their escape mutations. Further evaluation of a series of SARS-CoV-1/2-cross-reactive bNAbs showed a negative correlation between the neutralizing activities against SARS-CoV-1 and SARS-CoV-2 Omicron variant. Together, these results suggest the necessity of using cross-neutralization against SARS-CoV-1 and SARS-CoV-2 Omicron as criteria for rational design and development of potent pan-sarbecovirus vaccines and bNAbs. This article is protected by copyright. All rights reserved.