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Structural candidates for the super-size cubic carbon phase discovered in the Popigai crater are proposed. They are superhard transparent insulators as the discovered sample and their simulated XRD can partially explain the experimental results.

This article is concerned with causal mediation analysis with varying indirect and direct effects. We propose a varying coefficient mediation model, which can also be viewed as an extension of moderation analysis on a causal diagram. We develop a new estimation procedure for the direct and indirect effects based on B-splines. Under mild conditions, rates of convergence and asymptotic distributions of the resulting estimates are established. We further propose a F-type test for the direct effect. We conduct simulation study to examine the finite sample performance of the proposed methodology, and apply the new procedures for empirical analysis of behavioral economics data.

Within the past 2 decades, three highly pathogenic human coronaviruses have emerged, namely, severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The health threats and economic burden posed by these tremendously severe coronaviruses have paved the way for research on their etiology, pathogenesis, and treatment. Compared to SARS-CoV and SARS-CoV-2, MERS-CoV genome encoded fewer accessory proteins, among which the ORF4b protein had anti-immunity ability in both the cytoplasm and nucleus. Our work for the first time revealed that ORF4b protein was unstable in the host cells and could be degraded by the ubiquitin proteasome system. After extensive screenings, it was found that UBR5 (ubiquitin protein ligase E3 component N-recognin 5), a member of the HECT E3 ubiquitin ligases, specifically regulated the ubiquitination and degradation of ORF4b. Similar to ORF4b, UBR5 can also translocate into the nucleus through its nuclear localization signal, enabling it to regulate ORF4b stability in both the cytoplasm and nucleus. Through further experiments, lysine 36 was identified as the ubiquitination site on the ORF4b protein, and this residue was highly conserved in various MERS-CoV strains isolated from different regions. When UBR5 was knocked down, the ability of ORF4b to suppress innate immunity was enhanced and MERS-CoV replication was stronger. As an anti-MERS-CoV host protein, UBR5 targets and degrades ORF4b protein through the ubiquitin proteasome system, thereby attenuating the anti-immunity ability of ORF4b and ultimately inhibiting MERS-CoV immune escape, which is a novel antagonistic mechanism of the host against MERS-CoV infection.

In this work, we prepared CuCe/Ti catalysts in a dielectric barrier discharge (DBD) reactor and proposed a new method for flue gas mercury oxidation using DBD coupling CuCe/Ti catalyst. Our experiments verified the oxidation efficiency of flue gas Hg0 (ηHg) and clarified the influence of O2 content, NO concentration, SO2 concentration, water vapor content, and discharge voltage on ηHg. The oxidation mechanism of Hg0 in the DBD-CuCe/Ti reactor was also illustrated. The Hg0 oxidation experiment on the simulated flue gas (70 μg/m3 Hg0 + 300 mg/m3 NO + 1000 mg/m3 SO2 + 6%O2) with a flow rate of 1 L/min showed that when the amount of catalyst was 1.25 g and the discharge voltage was 9.5 kV, a ηHg of 93% can be achieved, which indicates that the DBD coupling CuCe/Ti technology is suitable for Hg0 conversion and flue gas mercury removal.

We performed density functional theory calculations to investigate the electronic and magnetic properties of h-BN/MoS2 heterostructures intercalated with 3d transition-metal (TM) atoms, including V, Cr, Mn, Fe, Co, and Ni atoms. It was found that metal and magnetic semiconductor characteristics are induced in the h-BN/MoS2 heterostructures after intercalating TMs. In addition, the results demonstrate that h-BN sheets could promote charge transfer between the TMs and the heterogeneous structure. Specifically, the h-BN/MoS2 heterostructure transforms from an indirect semiconductor to a metal after intercalating V or Cr atoms in the interlayers. For Mn, Fe, and Co atoms, the bandgaps of the intercalated heterojunction systems become smaller when the spin polarization is 100% at the highest occupied molecular orbital level. However, the system intercalated with Ni atoms exhibits no spin polarization and non-magnetic character. Strong covalent-bonding interactions emerged between the intercalated TMs and the nearest S atom of the h-BN/MoS2 heterostructure. In addition, the magnetic moments of the TM atoms show a decreasing trend for all the interstitial intercalated heterostructures compared with their free-standing states. These results reveal that h-BN/MoS2 heterostructures with intercalated TMs are promising candidates for application in multifarious spintronic devices.

Van der Waals (vdW) heterostructure, vertically assembled by two kinds of two-dimensional layered materials with extraordinary electronic and optical properties, has emerged as an interesting candidate in the applications of electronics and optoelectronics. It is known that vacancies are crucial in determining the physical properties of materials, and always exist in the materials during the process of actual experimental preparations and can be artificially introduced. In the present work, the structures and electronic properties of a black phosphorus/molybdenum disulfide (BP/MoS2) vdW heterostructure with P atom vacancies are investigated via first principles calculations. Based on the structural symmetry, two types of heterostructures with single-atom vacancy and three types of heterostructures with diatomic vacancies are constructed. It is found that the presence of a single P atom vacancy leads to the transformation from semiconductor to metal in the BP/MoS2 heterostructure, which is mainly due to the contribution of the remaining P atomic p orbitals based on analyses of the partial density of states (PDOS). On the other hand, the heterostructures with diatomic P atom vacancies still maintain their pristine semiconductor features, along with a decrease in their bandgap value. In addition, the plane electrostatic potential indicates that the introduction of P atom vacancy defects causes a change in the electrostatic potential of the BP atomic layer, resulting in asymmetric electrostatic potential on both sides of the BP layer. Finally, it is interesting to note that the accumulation-depletion of electrons occurs around the vacancy, but also partially emerges at the MoS2 layer. Our results provide the possibility for the application of 2D-vacancy-defect heterostructure systems.

In risk theory, ruin probabilities and dividend strategies have drawn lots of attentions. The dual risk model assumes that the surplus process decreases at a constant rate over time and gains by me...

Facilitating the mass transfer and spatial charge separation is a great challenge for achieving efficient oxidation of NO and outstanding sulfur resistance. Herein, a hydrothermal-assisted confinement growth technique is used to fabricate well-defined three-dimensional CuOx@MnOx hetero-shelled hollow-structure catalysts. By integrating the coupled plasma space reactor and the porous hierarchical structure of the catalyst, excellent stability (10 h) and high conversion of NO (93.86%) are reached under the concentration of SO

Objective. DNA methylation played a vital role in the progression of diabetic retinopathy. In this study, we aimed to explore the role of DNA cytosine-5-methyltransferase 1 (DNMT1) in the development of early diabetic retinopathy and its potential underlying mechanism. Methods. Eight-week-old healthy Mongolian gerbils were used to establish type 1 diabetes using streptozotocin (STZ). Alteration of weight, fasting blood glucose, density of RGCs (Tuj1-labeled), and H&E-stained retinal cross sections were applied to evaluate the diabetic retinopathy mouse model. The global DNA methylation level of the retina at different time points after STZ injection was measured using the global methylation assay. Western blot was used to detect the protein expression of DNMT1, DNA methyltransferase 3A (DNMT3A), and 3B (DNMT3B). Quantitative reverse transcription-polymerase chain reactions (qRT-PCR) and western blot were used to determine the expression of CDKN2B. Cell proliferation and cell cycle were evaluated by the MTS assay and flow cytometry. Results. STZ injection caused the increased global DNA methylation level, which reached a maximum at 6 weeks after injection. Moreover, STZ injection caused the damage of RGCs. At 6 weeks after STZ injection, the expression levels of DNMT1 and DNMT3B were significantly increased in the STZ group. DNMT1-induced DNA hypermethylation inhibited the expression of CDKN2B (a negative regulator of cell cycle). DNMT1-mediated DNA methylation facilitated RGC proliferation via regulating the expression of CDKN2B. Conclusion. DNMT1-mediated DNA methylation played an important role in STZ-induced diabetic retinopathy via modulating CDKN2B expression.

Based on first-principles calculations, the ground state configuration (Cmma-CH) of a hydrogenated biphenylene sheet ( Science 2021, 372, 852) is carefully identified from hundreds of possible candidates generated by RG2 code ( Phys. Rev. B. 2018, 97, 014104). Cmma-CH contains four inequivalent benzene molecules in its crystalline cell due to its Cmma symmetry. Hydrogen atoms bond to carbon atoms in each benzene with a boat-like (DDUDDU) up/down sequence and reversed boat-1 (UUDUUD) sequence in adjacent benzene rings. Cmma-CH is energetically less stable than the proposed allotropes of hydrogenated graphene, but the formation energy for hydrogenating a biphenylene sheet is remarkably lower than that for hydrogenating graphene to graphane. Our results of mechanical and dynamical stability also confirm that Cmma-CH is a stable 2D hydrocarbon, which is expected to be realized experimentally. Especially, biphenylene undergoes a transition from normal metal to a wide band gap insulator (4.645 eV) by hydrogenation to Cmma-CH, which has potential applications in nanodevices at elevated temperatures and high voltages.

An integrated system of dielectric barrier discharge (DBD) combined with MnCu/Ti catalyst and wet electrostatic precipitator (DBD–catalyst–WESP) was constructed for simultaneous removal of SO2 and NO. The removal mechanism and the effects of special energy density (SED) and initial concentrations of NO and SO2 on oxidation efficiency were investigated. Experimental results showed that compared with Mn/Ti and Cu/Ti, the MnCu/Ti catalyst exhibited a higher dispersion of active constituents and has more catalytic oxidation active substances. The removal efficiencies of NO and SO2 in the DBD-catalyst system increased with increasing SED (15–275 J/L), and the lower the initial concentration was, the higher were the simultaneous removal efficiencies of NO and SO2. The competitive relationship between the removal of NO and SO2 was clarified. Compared with the DBD–catalyst system, the DBD–catalyst–WESP system significantly improved the simultaneous removal efficiencies of NO and SO2. With low initial concentratio...

OBJECTIVES: Food insecurity is a dynamic phenomenon within a given month and across seasons. It remains unknown how food insecurity influences low-income adults’ day-to-day affective well-being, which is associated with long-term mental and physical health. In this pilot study, we explored the association between daily food insecurity and affect over a 2-month period (spanning 2 seasons) in a sample of low-income adults in Central Pennsylvania. METHODS: A total of 22 healthy low-income adults were recruited during the fall months (September, October, or November) in 2019, 18 of whom were also followed in the winter months (February or March) in 2020. Using an ecological momentary assessment framework administered on smart phones over a three-week-long wave (2nd – 4th week) in each survey month, daily food insecurity (once daily), and positive and negative affect (5 times daily) were collected. Time Varying Effect Models were used to estimate the association between levels of daily food insecurity and daily aggregated positive/negative affect as a function of study day, adjusting for gender, race/ethnicity, employment, and poverty status. RESULTS: A total of 713 person-days (84.9% of what was possible) of daily-level data was collected. Food insecurity was reported in 42.9% and 36.0% of participants in the fall and winter months, respectively. Greater daily food insecurity was associated with significantly lower positive affect scores in the 3rd week of the fall months (β ranged from −1.40 (95% CI −2.62, −0.18) to −3.17 (95% CI: −5.93, −0.42)) and in the 4th week of the winter months (β ranged from −2.24 (95% CI: −4.08, −0.39) to −2.84 (95% CI: −4.28, −1.40)). No consistent association was identified between daily food insecurity and negative affect. CONCLUSIONS: Daily food insecurity was associated with lower positive affect in the second half of the months in both fall and winter seasons. Future large observational studies should verify our study findings in order to better identify, target, and intervene in food insecure adults who are at-risk of adverse mental health outcomes. FUNDING SOURCES: The National Center for Advancing Translational Sciences, National Institutes of Health (UL1TR002014) and the Broadhurst Career Development Professorship for the Study of Health Promotion and Disease Prevention.

We performed density functional theory calculations to investigate the electronic and magnetic properties of h-BN/MoS2 heterostructures intercalated with 3d transition-metal (TM) atoms, including V, Cr, Mn, Fe, Co, and Ni atoms. It was found that metal and magnetic semiconductor characteristics are induced in the h-BN/MoS2 heterostructures after intercalating TMs. In addition, the results demonstrate that h-BN sheets could promote charge transfer between the TMs and the heterogeneous structure. Specifically, the h-BN/MoS2 heterostructure transforms from an indirect semiconductor to a metal after intercalating V or Cr atoms in the interlayers. For Mn, Fe, and Co atoms, the bandgaps of the intercalated heterojunction systems become smaller when the spin polarization is 100% at the highest occupied molecular orbital level. However, the system intercalated with Ni atoms exhibits no spin polarization and non-magnetic character. Strong covalent-bonding interactions emerged between the intercalated TMs and the nearest S atom of the h-BN/MoS2 heterostructure. In addition, the magnetic moments of the TM atoms show a decreasing trend for all the interstitial intercalated heterostructures compared with their free-standing states. These results reveal that h-BN/MoS2 heterostructures with intercalated TMs are promising candidates for application in multifarious spintronic devices.

In this work, we prepared CuCe/Ti catalysts in a dielectric barrier discharge (DBD) reactor and proposed a new method for flue gas mercury oxidation using DBD coupling CuCe/Ti catalyst. Our experiments verified the oxidation efficiency of flue gas Hg0 (ηHg) and clarified the influence of O2 content, NO concentration, SO2 concentration, water vapor content, and discharge voltage on ηHg. The oxidation mechanism of Hg0 in the DBD-CuCe/Ti reactor was also illustrated. The Hg0 oxidation experiment on the simulated flue gas (70 μg/m3 Hg0 + 300 mg/m3 NO + 1000 mg/m3 SO2 + 6%O2) with a flow rate of 1 L/min showed that when the amount of catalyst was 1.25 g and the discharge voltage was 9.5 kV, a ηHg of 93% can be achieved, which indicates that the DBD coupling CuCe/Ti technology is suitable for Hg0 conversion and flue gas mercury removal.

In this work, the ultra-uniform amidated nitrogen (N)-doped carbon sphere (ANG-Cs) adsorbent with different pore sizes and modified by kinds of functional groups was developed for efficient carbon dioxide (CO2) adsorption, simultaneously obtaining the excellent selectivity of CO2/N2 from the simulated ultra-low emission flue gas. We fabricated the uniformly monodispersed glucose-based carbon microspheres via a creative ethanol-assisted hydrothermal method, and also systematically explored and discussed the relationship between porous structures functional alkaline-containing N-groups and CO2 adsorption capacity. Impressively, the pore size distribution arranged from micro- to mesoporous region along with large surface area of 1217 m2/g, that is benefit for the adsorption of small acid gas like CO2. Moreover, the adsorption capacity of the optimized ANG-Cs reached 4.89 mmol/g under 298 K and 1 bar, and the predictable adsorption selectivity of pure CO2/N2 was as high as 43 in the simulated ultra-low emission flue gas. More importantly, when compared with some advanced MOF-based adsorbents, ANG-Cs not only owns similar CO2 adsorption performance, but also keeps higher water resistance, chemical stability and lower cost. Therefore, this promising ANG-Cs with green synthesis for the controllable CO2 adsorption and separation pushes the progress in industry application of ultra-low emission gas.

With the outbreak of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), coronaviruses have begun to attract great attention across the world. Of the known human coronaviruses, however, Middle East respiratory syndrome coronavirus (MERS-CoV) is the most lethal. Coronavirus proteins can be divided into three groups: nonstructural proteins, structural proteins, and accessory proteins. While the number of each of these proteins varies greatly among different coronaviruses, accessory proteins are most closely related to the pathogenicity of the virus. We found for the first time that the ORF3 accessory protein of MERS-CoV, which closely resembles the ORF3a proteins of severe acute respiratory syndrome coronavirus and SARS-CoV-2, has the ability to induce apoptosis in cells in a dose-dependent manner. Through bioinformatics analysis and validation, we revealed that ORF3 is an unstable protein and has a shorter half-life in cells compared to that of severe acute respiratory syndrome coronavirus and SARS-CoV-2 ORF3a proteins. After screening, we identified a host E3 ligase, HUWE1, that specifically induces MERS-CoV ORF3 protein ubiquitination and degradation through the ubiquitin-proteasome system. This results in the diminished ability of ORF3 to induce apoptosis, which might partially explain the lower spread of MERS-CoV compared to other coronaviruses. In summary, this study reveals a pathological function of MERS-CoV ORF3 protein and identifies a potential host antiviral protein, HUWE1, with an ability to antagonize MERS-CoV pathogenesis by inducing ORF3 degradation, thus enriching our knowledge of the pathogenesis of MERS-CoV and suggesting new targets and strategies for clinical development of drugs for MERS-CoV treatment.

Metal atom adsorption is recently considered to be an efficient approach to achieve stability of black phosphorus required by practical devices with no damage to its pristine excellent properties. Using first-principles calculations, we studied the structures and electronic properties of monolayer black phosphorus with Fe atom adsorption under different biaxial strain. Monolayer BP becomes an indirect bandgap semiconductor due to the contribution of adsorbed Fe atom. Strain is considered as a promising way to turn the electronic structures of the adsorption systems. The compressive strain reduces the band gap value of the systems, and eventually results in a semiconductor-metal transition when the strain reaches −8%. The tensile strain would turn the value of band gap ranging from 0.96 eV to 0.60 eV, and an indirect-direct band gap transition would occur with the tensile strain of 4%. In addition, it is found that the charge density difference and charge transfer nearly unchanged under different strain, means that the Fe–P covalent bonds are very strong. The combination of adjustable electronic properties with stability makes black phosphorus an attractive material for fundamental physics studies.

Antimony phosphorus in the alpha phase (α-SbP) is a novel two-dimensional binary material with suitable band gap and environmental stability, it has attracted attention for its promising applications in the field of optoelectronics. In this work, the electronic and optical properties of α-SbP monolayer under biaxial strain have been studied by first principles calculation method based on density functional theory. It is found that when the tensile strain is applied, the band gap value of monolayer SbP increases firstly and then decreases under tensile strain, but the whole band gap value fluctuated is controlled within 0.08 eV. However, in the process of applying compressive strain, the band gap value decreases linearly with the strain value, and semiconductor-metal transition occurs at about −5% strain value. This is due to the difference in coupling between Sb and P atoms. Its optical properties under different strains are analyzed in detail, and it is found that the optical properties of SbP changed little under tensile strain, the light absorption peak is mainly concentrated in the ultraviolet region. In contrast, the compressive strain significantly adjust the optical properties of SbP. The innovation of this work is that the optoelectronic properties of SbP are studied by means of biaxial strain regulation. We find that the optoelectronic properties of SbP are robust to tensile strain. On the other hand, compressive strain has a significant effect on the photoelectric properties of SbP, and semiconductor-metal phase transition occurs. The research work in this paper provides theoretical support for the applications of monolayer α-SbP as a robust tensile and flexible compression material in optoelectronic nanodevices.

For efficient conversion of elemental mercury (Hg0) in flue gas, we coupled the non-thermal plasma (NTP) and catalytic oxidation, and prepared MnCu/Ti catalytic through dielectric barrier discharge (DBD) reactor. The experimental system of DBD coupling MnCu/Ti catalytic oxidation was established. The catalytic oxidation performance and the influences of energy density (SED), oxygen content, H2O content, and the concentrations of NO and SO2 on the conversion efficiency of Hg0 were clarified. Based on the experimental results and DFT simulation results, the mechanism of the catalytic oxidation was elucidated. Our results showed that after coupling with MnCu/Ti, the conversion efficiency of Hg0 in DBD reactor under mild conditions increased from 42.9% to 86.7%, and the energy consumption decreased from 0.77 mg Hg0/kWh to 1.56 mg Hg0/kWh. The proposed method has the advantages of high efficiency, intensive and no secondary pollution, hence it has good application potential in Hg0 conversion and removal from flue gas.

This study mainly uses N-methyldiethanolamine (MDEA) as the main body of absorption, and uses three kinds of AAILs(AAILs), 1-butyl-3-methylimidazolium lysinate ([Bmim][Lys]), tetramethylammonium glycinate ([N1111][Gly]) and 1-butyl-3-methylimidazolium glycinate ([Bmim][Gly]) as accelerator, respectively. That forms a new blended aqueous solution for CO2 removal. The new AAILs-MDEA aqueous solution absorbent has stronger ability to absorb CO2, faster absorption rate and lower equipment corrosion. When the gas flow rate is 500ml/min and the liquid flow rate is 150ml/min, the best removal efficiency is achieved. At 313.2K, the removal efficiency of MDEA-[N1111] [Gly] absorbent can reach 100%; the effect of the three new alkanolamine aqueous solutions on CO2 absorption is: MDEA-[N1111][Gly]>MDEA-[Bmim] [Gly]>MDEA-[Bmim][Lys].

To investigate whether insulin can increase the production of reactive oxygen species (ROS) in bovine retinal microvascular endothelial cells (BRECs), the role of antioxidants in the insulin-induced exacerbation of diabetic retinopathy and the related mechanisms.BRECs were cultured in either 5 or 30 mM glucose for 3 days before stimulation with 100 nM insulin for 24 h or incubated with 1 mM apocynin, 100 μM LY294002, 50 μM U0126, 2 μM GF109203X, 250 U/ml catalase, 100 μg/ml ascorbic acid, 100 μM α-lipoic acid and 50 μM α-tocopherol before stimulation with 100 nM insulin. H(2)O(2) (200 μM) was added to cells to measure the VEGF protein expression. Intracellular ROS was measured by immunofluorescence and flow cytometry, superoxide anion measurement was done by cytochrome c reduction, and VEGF protein was measured by ELISA analysis.Insulin or (and) high glucose significantly increased intracellular ROS production in BRECs, and pretreatment of the cells with apocynin and LY294002 decreased insulin-induced superoxide anion production. Neither pretreatment with GF109203X nor U0126 showed an effect on the superoxide anion production. Ascorbic acid, α-lipoic acid, and α-tocopherol also decreased superoxide anion production. Furthermore, H(2)O(2) increased VEGF protein expression in BRECs and catalase suppressed insulin-induced VEGF protein expression.Insulin can increase ROS production through an NAD(P)H, phosphatidylinositol 3´-kinase-dependent mechanism in bovine retinal microvascular endothelial cells ex vivo. ROS can regulate insulin-induced VEGF expression. Supplementation with antioxidants may help to attenuate the transient worsening of retinopathy in diabetes caused by acute intensive insulin therapy.

Clinical trials have demonstrated that acute intensive insulin therapy may cause transient worsening of retinopathy in type 1 and type 2 diabetes patients. However, the related mechanism still remains controversial. The purpose of the present study was to investigate the effect of insulin on the mitochondrial membrane potential (△Ψm), reactive oxygen species (ROS) production, UCP-2 and VEGF expression in bovine retinal microvascular endothelial cells (BRECs) in the presence of normal or high glucose and the related mechanisms. BRECs were isolated as primary cultures and identified by immunostaining. Passage BRECs were initially exposed to normal (5 mM) or high glucose (30 mM) for 3 days, with equimolar L-glucose supplemented for osmotic equation. Then the cells were treated with 1 nM, 10 nM, or 100 nM insulin for 24 h: △Ψm and ROS production were determined by JC-1 and CM-H2DCFDA, respectively. Expression of UCP-2 and VEGF mRNA was determined by real-time RT-PCR; expression UCP-2 and VEGF protein was determined by Western-blotting analysis. A general ROS scavenger N-acetylcysteine (NAC, 10 mM) and an NADPH oxidase inhibitor apocynin (1 mmol/l) were added 1 h before treatment with 100 nM insulin. Insulin increased △Ψm, ROS production, and expression of UCP-2 and VEGF in BRECs at normal glucose (5 mM) in a dose-dependent manner. Low-dose insulin (1 nM) decreased △Ψm, ROS production, and UCP-2, VEGF expression in BRECs at high glucose (30 mM); and high-dose insulin (10 nM, 100nM) recovered △Ψm, ROS production, and UCP-2, VEGF expression. Pretreatment of cells with NADPH oxidase inhibitor apocynin significantly suppressed 100 nM insulin-induced ROS production (p