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Background: Coronavirus disease 2019 (COVID-19) is primarily a respiratory disease that has become a global pandemic. Close contact plays an important role in infection spread, while fomite may also be a possible transmission route. Research during the COVID-19 pandemic has identified long-range airborne transmission as one of the important transmission routes although lack solid evidence. Methods: We examined video data related to a restaurant associated COVID-19 outbreak in Guangzhou. We observed more than 40,000 surface touches and 13,000 episodes of close contacts in the restaurant during the entire lunch duration. These data allowed us to analyse infection risk via both the fomite and close contact routes. Results: There is no significant correlation between the infection risk via both fomite and close contact routes among those who were not family members of the index case. We can thus rule out virus transmission via fomite contact and interpersonal close contact routes in the Guangzhou restaurant outbreak. The absence of a fomite route agrees with the COVID-19 literature. Conclusions: These results provide indirect evidence for the long-range airborne route dominating SARS-CoV-2 transmission in the restaurant. We note that the restaurant was poorly ventilated, allowing for increasing airborne SARS-CoV-2 concentration.

Texture analysis is an emerging field that allows mathematical detection of changes in MRI signals that are not visible among image pixels. Alzheimer's disease, a progressive neurodegenerative disease, is the most common cause of dementia. Recently, multiple texture analysis studies in patients with Alzheimer's disease have been performed. This review summarizes the main contributors to Alzheimer's disease-associated cognitive decline, presents a brief overview of texture analysis, followed by review of various MR imaging texture analysis applications in Alzheimer's disease. We also discuss the current challenges for widespread clinical utilization. MR texture analysis could potentially be applied to develop neuroimaging biomarkers for use in Alzheimer's disease clinical trials and diagnosis.

Two different structures of MoSi2 coatings were prepared on Niobium based alloys by using a two step process. The as-deposited type(a) MoSi2 coating structure consists of a MoSi2 layer on the surface and a NbSi2 layer underneath, while the type(b) MoSi2 coating consists of an outer MoSi2 layer and an inner unsiliconized Mo layer. The oxidation behaviors of the two different types MoSi2 coatings were examined at 1200 °C for 100 h in air, and the mass gains of type(a) and type(b) MoSi2 coated specimens were 0.64 mg/cm2 and 0.59 mg/cm2 respectively. The excellent oxidation resistance of both type(a) and type(b) MoSi2 coated samples at 1200 °C was due to the formation of a dense and continuous SiO2 scale during oxidation. As the CTE mismatch between the outer MoSi2 coating and the inner layer, cracks distributed within both type(a) and type(b) MoSi2 coating structures.

The quasar SDSS J151653.22+190048.2 (J1516+1900) exhibits very peculiar spectral characters in the observed ultraviolet, optical, and infrared bands: the full widths at half maximum (FWHM) of its optical H α , H β , and infrared Pa α and Pa β emission lines are all larger than 5000 km/s, and the equivalent widths of these emission lines also approach to those of normal quasars; while the ultraviolet emission lines (Ly β , OVI, Ly α , NV, SiIV, and CIV) are dominated by intermediate-width emission lines (IELs) with a FWHM of ∼ 1700 km/s. This phenomenon can be explained as the effect of partial obscuration: the broad emission lines (BELs) in the ultraviolet waveband are heavily suppressed by the dust extinction, and thus the IELs become prominent; while the dust extinction is not significant in optical and infrared bands, and the IELs can hardly be detected due to the brightness of BELs. Using the IEL width and central supermassive black hole mass M BH ∼ 5.75 × 10 8 M ⊙ of J1516+1900, and assuming that the intermediate-width emission line region (IELR) is virialized, we estimate the distance of the IEL region to the central black hole is about 1.6 pc. On the other side, by combining the photoionization model calculations and observed IELs, we find that the IELR has a density of ∼ 10 12 cm − 3 , and the ionization parameter of ∼ 10 − 0.65 , and that its distance to the central region is ∼ 0.016 pc, which is only one percent of the virialized distance. This contradiction can provide an important clue for studying the geometry, physical condition, and origin of the IELRs in active galactic nuclei.

Iron-doped ZnTe (Fe2+:ZnTe) crystal can be used as promising gain media for mid-infrared laser. However, there are few studies in the optical properties of Fe2+:ZnTe crystal from mid-infrared to ultraviolet. In this work, large size Fe2+:ZnTe bulk crystal (the concentration of Fe ions is about 1019 cm−3) with a dimension of Φ30 mm × 50 mm was grown by the temperature gradient solution growth (TGSG) method. The luminescence and optical properties of Fe2+:ZnTe from terahertz wave to ultraviolet wave have been studied. The evaluated refractive index of Fe2+:ZnTe crystal is approximately 2.5–3.0 at the frequency range of 0.5–2.0 THz range. And its band gap is estimated to be about 2.24 eV. It is noted that strong absorptions at the wavelength of 2.8–4.7 μm and 705 nm were observed. Based on the experimental results, the energetic positions of Fe2+ center such as 3T1, 5T2, 5E in ZnTe crystal were proposed.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant has become the dominant lineage worldwide. Experimental studies have shown that SARS-CoV-2 Omicron variant is more stable on various environmental surfaces than the ancestral strains of SARS-CoV-2. However, the influences on the role of the contact route in SARS-CoV-2 transmission are still unknown. In this study, we built a Markov chain model to simulate the transmission of the Omicron and ancestral strains of SARS-CoV-2 within a household over a 1-day period from multiple pathways; that is, airborne, droplet, and contact routes. We assumed that there were two adults and one child in the household, and that one of the adults was infected with SARS-CoV-2. We assumed two scenarios. (1) Asymptomatic/presymptomatic infection, and (2) symptomatic infection. During asymptomatic/presymptomatic infection, the contact route contributing the most (37%-45%), followed by the airborne (34%-38%) and droplet routes (21%-28%). During symptomatic infection, the droplet route was the dominant pathway (48%-71%), followed by the contact route (25%-42%), with the airborne route playing a negligible role (10%). Compared to the ancestral strain, although the contribution of the contact route increased in Omicron variant transmission, the increase was slight, from 25%-41% to 30%-45%. With the growing concern about the increase in the proportion of asymptomatic/presymptomatic infection in Omicron strain transmissions, the airborne route, rather than the fomite route, should be of focus. Our findings suggest the importance of ventilation in the SARS-CoV-2 Omicron variant prevention in building environment.

This study examined whether aggression among students in China rose or fell during 2003–2016. We applied a cross-temporal meta-analysis of 90 studies using Aggression Questionnaire (Buss & Perry, 1992) responses by 87,319 students (primary school students through senior high students). The results showed less aggression in later years. The decline in aggression was greater among junior high school students than among other students. Otherwise, the decline in aggression did not differ across gender or across regions (Eastern China, Central China, Western China).

Seepage flow is important because it is useful for production optimization and well spacing decisions. In this study, an enclosed high-precision seepage flow apparatus is used to determine the seepage flow characteristics of the Qianjiang shale reservoir in China under various pressures from 3 MPa to 24 MPa. The results revealed that the seepage flow curve has an inverse-spoon shape, which is completely different from the results for low-permeability and tight sandstone reservoirs, as reported in the literature. In addition, according to the full-scale pore size distribution technique, the modular automated processing system (MAPS), and the nuclear magnetic resonance (NMR) T2 spectrum before and after the seepage flow experiments, the seepage flow characteristics of the Qianjiang shale oil reservoir were not only caused by the boundary effect, but also dependent upon the stress sensitivity. It was also found that micro-fractures or macro-pore were compressed as the effective stress increased in the experiment. Moreover, a new non-Darcy model for a shale reservoir was derived, and the model was verified using experimental data. This model demonstrated it would be a good candidate for quantitative evaluation of affecting factors. It can also be applied to determine the main controlling factor. The calculated results showed that the shape of the nonlinear flow portion of the seepage flow curve for the Qianjiang shale oil reservoir was primarily dependent upon the effect of stress sensitivity. However, the linear flow portion of the seepage flow curve was dependent upon the combined effects of stress sensitivity and the boundary layer. Therefore, from the enhanced individual-well production point of view, the control of production pressure drops and selection of rational well spacing is important for the effective development of shale oil reservoirs.

Tellurite glasses of TeO2 BaF2−REF3 (RE = La, Gd, and Y) co-doped with Er3+/Yb3+ were prepared and investigated comparatively for optical fiber temperature sensors. For this purpose, their thermal and optical properties were examined in detail. The J-O theory was adopted to estimate the transition properties based on absorption spectra. The dominant green emissions were observed in both of the downshifting and upconversion luminescence. The optical temperature sensing abilities based on the FIR of Er3+ green emissions were studied under both of the UV (380 nm) and NIR (980 nm) excitations. Results show that these three tellurite glasses, especially for the TBG glass, should be very qualified for the design of optical fiber temperature sensors under different excitation modes.

A MoSi2 coating was prepared on Nb-10Hf-1Ti alloys by a two-step process. The first step was arc ion plating (AIP) of the Mo layer, and the second step was halide-activated pack cementation (HAPC) of Si. The coating is composed of an outer layer of MoSi2 and an inner bond layer. After oxidation testing at 1200 °C for 100 h in a static air atmosphere, the mass gain of the coated specimen was 0.64 mg/cm2. The good oxidation resistance of the MoSi2 coating is attributed to the protective SiO2 scale generated by the oxidation process.

Fluoxetine (Flx), a selective serotonin reuptake inhibitor, is extensively used to treat mood and anxiety disorders. Previous animal studies have shown that early-life exposure to Flx results in long-lasting behavioral alterations and neuroplasticity in the hippocampus and cortex, which may persist into adulthood. It remains unclear whether repeated Flx treatment in normal adult animals can induce lasting neuroplasticity and behavioral alterations persisting long beyond the treatment period. In this study, young adult rats (about 9 weeks old) were treated with Flx (10 mg/kg body weight, twice daily) for 15 consecutive days, and the effects of Flx on medial prefrontal cortex (mPFC) neuroplasticity and mPFC-related behaviors were assessed 20 days after the last injection. It was observed that the mPFC of Flx-treated rats had significant increases in the number of 5-bromodeoxyuridine-positive (BrdU+) cells, dendritic complexity/spine density in layer II/III pyramidal neurons, and brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB) expression levels, as well as a significant decrease in the number of parvalbumin-positive (PV+) interneurons. The Flx-treated rats exhibited higher motivation to explore new environments, evidenced by a significantly increased number of entries into the novel arm in the Y-maze test. However, they did not show any significant changes in the anhedonia and anxiety levels measured by sucrose preference and elevated plus maze tests respectively. In conclusion, repeated Flx treatment, with the paradigm used, induces long-lasting neuroplastic changes in the mPFC of normal adult rats; such changes and related behavioral manifestations may persist up to 20 days after the last dose.

Constructing electronic systems without an external power source is urgently required toward self-powered photodetection. In this work, we proposed a self-driven photodetection system with a MoS2 nanosheets photodetector as light intensity sensor, a vertical contact-separate mode triboelectric nanogenerator (CS-TENG) as power source, and several LEDs as alarm. The MoS2 based planar photodetector was fabricated by conventional photolithography technique and lift-off process. It is highly sensitive for visible light illumination with high current on-off ratio and excellent reproducibility characteristics under light on-off switching. When conjuncting these functional devices, the induced output voltage of the CS-TENG is tuned by the load resistance of the photodetector, which is responded to the light intensity. The mechanism can be ascribed to the impedance matching effect between specific output characteristics of TENG and working status of photodetector. By adding a Zener diode acts as a voltage regulator, the self-driven renders the voltage and current varying from 1.58 to 20.60 V and 0.06–4.78 μA in a range of light intensity from 0 to 3.19 W/m2, respectively. Finally, it is demonstrated that the output of CS-TENG varies with the variable working states of the MoS2 photodetector and then accurately reflects on the lighted number of LEDs.

A new 3D metal-organic framework (PMI)2[Zn4(μ4-O)Br2L2] (1, PMI = 1-propyl-3-methylimidazolium, H3L = biphenyl-3,4′,5-tricarboxylic acid) was prepared from tricarboxylic acid H3L and Zn(NO3)2 under ionothermal conditions. Single crystal X-ray diffraction analysis reveals that the anionic framework possesses a (3,6)-connected topological network and contains rare {Zn4(μ4-O)Br2} clusters as building units. The compound was further characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Interestingly, 1 can serve as a sensitive and recyclable luminescent probe to detect Fe3+ ions. In addition, 1 can effectively and selectively absorb cationic dyes, possibly due to the anionic nature of the framework.

ZnTe crystal is a promising electro-optical crystal materials applied for THz generation and detection. However, there is still a big challenge to obtain large sized high quality ZnTe crystals. In this work, large sized ZnTe bulk crystals with Φ30 mm × 150 mm were grown by the traveling solvent melting zone (TSMZ) method. With the characterization of the optical and electrical properties of as-grown ZnTe crystals, the band gap (2.22 eV), high IR transmittance (around 60%), high resistivity (3.5 × 103 Ω·cm), low density (1.3 × 105 cm−2) and small sizes (3 μm - 5 μm) of Te inclusions in ZnTe crystals, low etch pit densities (1.5 × 105 cm−2), high peak intensity to FWHM ratio (2.5 × 104) of the LO peak in the Raman spectra were obtained. Furthermore, the THz transmission spectra was measured and the maximum transmittance is more than 40% at the range of 0.3 - 3 THz. Based on these results, high quality and large aspect ratio ZnTe bulk crystals can be obtained by the TSMZ technique. Our work has greatly facilitated the application of ZnTe crystals in THz device.