NiS助催化剂的硫调控光沉积合成及其增强g-C3N4的光催化产氢性能

作为一种非金属聚合半导体,石墨相氮化碳(g-C3N4)具有特殊的能带结构、可见光响应能力以及优良的物理化学性质以及生产成本低等特点,因而已成为目前光催化领域的研究热点.然而,由于g-C3N4被光激发的电子与空穴极易复合,导致g-C3N4材料的光催化性能并不理想.而助剂修饰是实现光生载流子有效分离以提高光催化活性的有效途径.众所周知,贵金属Pt可以作为光催化产氢的反应位点,但高昂的成本限制了它的实际应用.所以,开发高效的非贵金属助剂很有必要.近年来,NiS作为优良的电子助剂在光催化领域受到广泛关注.大量研究表明,NiS可以作为g-C3N4的产氢活性位点用于提高其光催化产氢性能.NiS助剂主要是通过水热、煅烧和液相沉淀的方法修饰在g-C3N4的表面上.相较而言,助剂的光沉积方法具有一些独特的优势,例如节能、环保、简易并且能够实现其原位牢固地沉积在光催化剂的表面.然而g-C3N4光生电子和空穴强还原和氧化能力容易导致像Ni^2+的还原和S^2-的氧化等副反应发生,因此NiS助剂很难光沉积在g-C3N4材料表面.本文采用硫调控的光沉积法成功合成了NiS/g-C3N4光催化材料,该法利用g-C3N4在光照条件下产生的光生电子结合S以及Ni^2+生成NiS,然后原位沉积在g-C3N4表面.由于E0(S/NiS)(0.096 V)比E0(Ni^2+/Ni)(-0.23 V)更正,所以NiS优先原位沉积在g-C3N4表面.因此,硫调控的光沉积法促进了NiS的生成,并抑制了金属Ni等副反应的形成.通过X射线光电子能谱分析NiS/g-C3N4的表面化学态,表明该方法能成功地将NiS修饰在g-C3N4的表面,这也得到透射电镜和高分辨透射电镜结果的证实.光催化产氢的结果表明,NiS/g-C3N4光催化剂实现了良好的光催化性能,其最优产氢速率(244μmol h^‒1 g^‒1)接近于1 wt%Pt/g-C3N4(316μmol h^‒1 g^‒1).这是因为硫调控的光沉积法实现NiS助剂在g-C3N4表面的修饰,从而促进光生电子与空穴的有效分离,进而提高光催化制氢效率.此外,在该方法中,NiS的形成通常在g-C3N4光生电子的表面传输位点上,因此也能够使NiS提供更多的活性位点以提高界面产氢催化反应速率.电化学表征结果也进一步证明NiS/g-C3N4光催化剂加快了电子与空穴的分离和转移.更重要的是,这种简易且通用的方法还可以实现CoSx,CuSx,AgSx对g-C3N4的助剂修饰,并且都提高了g-C3N4的光催化产氢性能,表明该方法具有一定的普适性,为高效光催化材料的合成提供了新的思路.

NS1结合蛋白通过转录抑制c-Myc增强食管鳞状细胞癌的放疗敏感性

背景与目的基于顺铂的化疗联合放疗是晚期食管鳞状细胞癌(esophageal squamous cell carcinoma,ESCC)的标准疗法。NS1结合蛋白(NS1-binding protein,NS1-BP)是BTB-kelch蛋白家族中的一员,已被证明可通过抑制c-Myc进而抑制HeLa细胞增殖。在本研究中,我们检测NS1-BP表达在ESCC中的潜在作用,特别是其在ESCC放疗敏感性方面的作用。方法对于两组接受基于顺铂化疗且联合放疗的ESCC患者(研究组n=98;验证组n=46),采用免疫组化方法分别检测NS1-BP表达。使用正常食管黏膜组织块作为对照。我们也进行了一系列体外和体内实验来检测过表达NS1-BP对ESCC细胞各方面的潜在影响,尤其关注的是对电离辐射的敏感性方面的影响。结果在研究组中,59%(85/144)的ESCC样本观察到了NS1-BP下调。在研究组和验证组中,NS1-BP下调与放化疗抵抗和较短的疾病特异生存期(disease-specific survival,DSS)均具有相关性。体内和体外培养条件下过表达NS1-BP均能大幅度提高ECSS细胞对放疗的敏感性。NS1-BP也显著增强IR诱导的凋亡,阻断IR诱导的G2/M细胞周期阻滞和ATM/Chk1磷酸化。免疫沉淀反应显示NS1-BP可以与c-Myc启动子区相互作用从而抑制其转录。在ESCC组织中,c-Myc表达与NS1-BP水平负相关,与较短的疾病特异生存期相关。结论我们的研究结果显示了NS1-BP在ESCC放疗敏感性中的作用和重要性。以NS1-BP/c-Myc通路为靶标有望开发一种新的ESCC治疗策略。

Albedo of Coastal Landfast Sea Ice in Prydz Bay,Antarctica:Observations and Parameterization

The snow/sea-ice albedo was measured over coastal landfast sea ice in Prydz Bay, East Antarctica（off Zhongshan Station）during the austral spring and summer of 2010 and 2011. The variation of the observed albedo was a combination of a gradual seasonal transition from spring to summer and abrupt changes resulting from synoptic events, including snowfall, blowing snow, and overcast skies. The measured albedo ranged from 0.94 over thick fresh snow to 0.36 over melting sea ice. It was found that snow thickness was the most important factor influencing the albedo variation, while synoptic events and overcast skies could increase the albedo by about 0.18 and 0.06, respectively. The in-situ measured albedo and related physical parameters（e.g., snow thickness, ice thickness, surface temperature, and air temperature） were then used to evaluate four different snow/ice albedo parameterizations used in a variety of climate models. The parameterized albedos showed substantial discrepancies compared to the observed albedo, particularly during the summer melt period, even though more complex parameterizations yielded more realistic variations than simple ones. A modified parameterization was developed,which further considered synoptic events, cloud cover, and the local landfast sea-ice surface characteristics. The resulting parameterized albedo showed very good agreement with the observed albedo.

Crystal Type Iof Azilsartan Polymorphs: Preparation and Analysis

Azilsartan (2-ethoxy-1-([2’-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl)-1H-benzimidazole-7-carboxylic acid) is a new angiotensin II receptor antagonist used in the treatment of hypertension. This paper describes the preparation of type I crystal and its single crystal diffraction data, the comparison of the powder diffraction data for both type I and II crystals as well as their stability and solubility in methanol.

A nanoplatform with oxygen self-supplying and heat-sensitizing capabilities enhances the efficacy of photodynamic therapy in eradicating multidrug-resistant biofilms

Bacterial biofilms,especially those caused by multidrug-resistant bacteria,have emerged as one of the greatest dangers to global public health.The acceleration of antimicrobial resistance to conventional an-tibiotics and the severe lack of new drugs necessitates the development of novel agents for biofilm eradication.Photodynamic therapy(PDT)is a promising non-antibiotic method for treating bacterial infections.However,its application in biofilm eradication is hampered by the hypoxic microenvironment of biofilms and the physical protection of extracellular polymeric substances.In this study,we develop a composite nanoplatform with oxygen(O_(2))self-supplying and heat-sensitizing capabilities to improve the PDT efficacy against biofilms.CaO_(2)/ICG@PDA nanoparticles(CIP NPs)are fabricated by combining calcium peroxide(CaO_(2))with the photosensitizer indocyanine green(ICG)via electrostatic interactions,followed by coating with polydopamine(PDA).The CIP NPs can gradually generate O_(2)in response to the acidic microenvironment of the biofilm,thereby alleviating its hypoxic state.Under near-infrared(NIR)irradiation,the nanoplatform converts O_(2)into a significant amount of singlet oxygen(^(1)O_(2))and heat to eradicate biofilm.The generated heat enhances the release of O_(2),accelerates the generation of^(1)O_(2)in PDT,increases cell membrane permeability,and increases bacterial sensitivity to^(1)O_(2).This nanoplatform significantly improves the efficacy of PDT in eradicating biofilm-dwelling bacteria without fostering drug resistance.Experiments on biofilm eradication demonstrate that this nanoplatform can eradicate over 99.9999%of methicillin-resistant Staphylococcus aureus(MRSA)biofilms under 5-min NIR irradiation.Notably,these integrated advantages enable the system to promote the healing of MRSA biofilm-infected wounds with negligible toxicity in vivo,indicating great promise for overcoming the obstacles associated with bacterial biofilm eradication.

Superhydrophobic photothermal coatings based on candle soot for prevention of biofilm formation

Bacterial biofilms formed on the material surfaces have posed a series of serious problems for human health and industries.The treatment of mature biofilms is particularly difficult because they are inher-ently highly resistant against antibiotics and other adverse factors.The prevention is strategically advan-tageous over the treatment,and thus the development of innovative surfaces with capability to inhibit biofilm formation is highly demanded.In this work,we developed a superhydrophobic photothermal coating for prevention of biofilm formation,which was based on candle soot with hierarchical structure and excellent light-to-heat conversion ability.This coating was fabricated by deposition of a candle soot layer on the substrate,followed by sequential chemical vapor deposition of tetraethoxysilane and immo-bilization of fluorinated silane to make the coating robust and superhydrophobic.The resulted coating could repel a majority of bacteria from the surface at the early stage,and then eradicate a small number of bacteria remained on the surface under a short-term irradiation of near-infrared laser.The combi-nation of anti-adhesive property and photothermal bactericidal property endowed the coating with good antibiofilm property to prevent biofilm formation for at least 2 weeks.This coating is facile for deposition on various substrates with good storage stability,showing great potential for diverse practical applications to solve the biofilm-associated problems of materials and devices.

Bacterial cellulose-based dressings with photothermal bactericidal activity and pro-angiogenic ability for infected wound healing

For most traditional wound dressings,it is challenging to simultaneously eliminate bacteria and promote angiogenesis to accelerate the healing process of bacteria-infected wounds.In this work,we develop a multifunctional dressing based on bacterial cellulose(BC)deposited with a tannic acid/Cu^(2+)ion/Mg^(2+)ion(TCM)complex film.Overall,the TCM complex exhibits robust interfacial adhesion to modify BC and good photothermal properties to effectively eradicate bacteria in the wound area under near-infrared(NIR)irradiation.The individual components of the TCM complex have several advantageous features for wound healing,such as antibacterial ability and negligible cytotoxicity;in particular,the released Cu^(2+)and Mg^(2+)ions are favorable for the proliferation,migration,and tube formation of endothelial cells in vitro.The results of in vivo experiments demonstrated that with the assistance of NIR irradiation,this composite dressing is more effective than traditional gauze or pristine BC dressing in promotion of angiogenesis and collagen deposition without causing remarkable inflammation,thereby accelerating the healing process of bacteria-infected full-thickness skin wounds.This work thus provides a simple and facile way to fabricate multifunctional BC-based dressings that could be potentially used for treating infected wounds.

Postnatal feeding with high-fat diet induces obesity and precocious puberty in C57BL/6J mouse pups： a novel model of obesity and puberty

Childhood obesity and obesity-related metabolic complications are induced by a high-fat postnatal diet. The lack of a suitable animal model, however, remains a considerable challenge in obesity studies. In the current study, we provided high-fat diet （HFD） to dams during lactation and to pups after weaning. We also developed a novel model of C57BL/6J mouse pups with HFD-induced postnatal obesity. Results showed that feeding with HFD induces fat deposition and obesity in pups. Furthermore, HFD more potently increased the body weight （BW） of male than female pups. HFD-fed female pups were obese, underwent precocious puberty, and showed increased kisspeptin expression in the hypothalamus. However, parental obesity and precocious puberty exerted no synergistic effects on the HFD-induced postnatal weight gain and puberty onset of the pups. Interestingly, some HFD-fed litters with normal BW also exhibited precocious puberty. This finding suggested that diet composition but not BW triggers puberty onset. Our model suggests good construction validity of obesity and precocious puberty. Furthermore, our model can also be used to explore the mutual interactions between diet-induced postnatal childhood obesity and puberty.

NS1-binding protein radiosensitizes esophageal squamous cell carcinoma by transcriptionally suppressing c-Myc

Background:Cisplatin-based chemotherapy with concurrent radiotherapy is a standard treatment for advanced esophageal squamous cell carcinoma(ESCC).NS1-binding protein(NS1-BP),a member of the BTB-kelch protein fam-ily,has been shown to inhibit the proliferation of Hela cells by suppressing c-Myc.In the present study,we examined the potential function role of NS1-BP expression in ESCC,and particularly,the sensitivity of ESCC to radiotherapy.Methods:NS1-BP expression was examined using immunohistochemistry in two cohorts(n=98 for the training cohort;n=46 for independent validation cohort)of ESCC patients receiving cisplatin-based chemotherapy and con-current radiotherapy.Normal esophageal mucosal tissue blocks were used as a control.We also conducted a series of in vitro and in vivo experiments to examine the potential effects of over-expressing NS1-BP on ESCC cells,and particu-larly their sensitivity to ionizing irradiation.Results:In the training cohort,NS1-BP downregulation was observed in 59%(85/144)of the ESCC specimens.NS1-BP downregulation was associated with chemoradiotherapeutic resistance and shorter disease-specific survival(DSS)in both the training and validation cohorts.Over-expressing NS1-BP in cultured ESCC cells substantially increased the cellular response to irradiation both in vitro and in vivo.NS1-BP also significantly enhanced IR-induced apoptosis,and abrogated IR-induced G2/M cell-cycle arrest and ATM/Chk1 phosphorylation.Immunoprecipitation assays indicated that NS1-BP could interact with c-Myc promoter regions to inhibit its transcription.In ESCC tissues,c-Myc expression was inversely correlated with NS1-BP levels,and was associated with a shorter DSS.Conclusions:Our findings highlight the role and importance of NS1-BP in radiosensitivity of ESCC.Targeting the NS1-BP/c-Myc pathway may provide a novel therapeutic strategy for ESCC.

Snow and ice thicknesses derived from Fast Ice Prediction System Version 2.0(FIPS V2.0)in Prydz Bay,East Antarctica:comparison with in-situ observations

In this paper,snow and ice thickness products derived from an updated Fast Ice Prediction System Version 2.0(FIPS V2.0)in Prydz Bay,East Antarctica,are introduced and compared with in-situ obser-vations.FIPS V2.0 is comprised of a newly-developed snowdrift parameterization compared to the original FIPS V1.0.The simulation domain covers the entire fast ice region in Prydz Bay and is config-ured to 720 grid cells,with a spatial resolution of 0.125°.The ERAInterim reanalysis from the European Centre for Medium-Range Weather Forecasting(ECMWF)were used as the atmospheric forcing.The in-situ observations were obtained near Zhongshan Station by the wintering team,and the measurement frequency of the snow and ice thicknesses was around one week.Both the FIPS V2.0 pro-ducts and in-situ observations introduced in this paper cover the time periods from 2012 to 2016.The primary assessments based on the in-situ observations show that FIPS V2.0 has mean biases of 0.01±0.07 m and 0.23±0.09 m for snow and ice thickness simula-tions,respectively.The results indicate that the updated FIPS V2.0 produces a reasonable snow thickness due to the newly-developed snowdrift parameterization,but it overestimates the ice thickness due to the cold bias in the air temperature forcing.These 2-D snow and ice thickness distributions provide important references for sea ice thermodynamic studies,remote sensing validations,and ice-breaker navigation assessments in this region.The dataset is avail-able at http://www.doi.org/10.11922/sciencedb.j00076.00066.

Toll-Like Receptor 4 Deficiency Causes Reduced Exploratory Behavior in Mice Under Approach-Avoidance Conflict

Abnormal approach-avoidance behavior has been linked to deficits in the mesolimbic dopamine（DA）system of the brain. Recently, increasing evidence has indicated that toll-like receptor 4（TLR4）, an important pattern-recognition receptor in the innate immune system,can be directly activated by substances of abuse, resulting in an increase of the extracellular DA level in the nucleus accumbens. We thus hypothesized that TLR4-dependent signaling might regulate approach-avoidance behavior. To test this hypothesis, we compared the novelty-seeking and social interaction behaviors of TLR4-deficient（TLR4^（-/-））and wild-type（WT） mice in an approach-avoidance conflict situation in which the positive motivation to explore a novel object or interact with an unfamiliar mouse was counteracted by the negative motivation to hide in exposed,large spaces. We found that TLR4^（-/-）mice exhibitedreduced novelty-seeking and social interaction in the large open spaces. In less stressful test apparatuses similar in size to the mouse cage, however, TLR4^（-/-）mice performed normally in both novelty-seeking and social interaction tests. The reduced exploratory behaviors under approachavoidance conflict were not due to a high anxiety level or an enhanced fear response in the TLR4^（-/-）mice, as these mice showed normal anxiety and fear responses in the open field and passive avoidance tests, respectively. Importantly,the novelty-seeking behavior in the large open field induced a higher level of c-Fos activation in the nucleus accumbens shell（NAc Sh） in TLR4^（-/-）mice than in WT mice. Partially inactivating the NAc Sh via infusion of GABA receptor agonists restored the novelty-seeking behavior of TLR4^（-/-）mice. These data suggested that TLR4 is crucial for positive motivational behavior under approach-avoidance conflict. TLR4-dependent activation of neurons in the NAc Sh may contribute to this phenomenon.

A numerical study of convective-scale downdrafts in the outer core of tropical cyclones in vertically varying environmental flows

The characteristics of convective-scale downdrafts in the outer core of tropical cyclones in the lower-and upper-layer vertical wind shear(VWS)are investigated based on two high-resolution idealized numerical experiments.Four types of outer-core downdrafts,originating from the lower troposphere,the midtroposphere,the upper level,and the tropopause,respectively,are found.The downdrafts originating from the lower and mid troposphere can penetrate down near the surface,and those originating from the tropopause in upper-layer VWS tend to penetrate more downward than in lower-layer VWS.Downdrafts tend to be located in the more upwind portion of the downshear-right quadrant in lower-layer VWS than in upper-layer VWS.The frequency of downdrafts outside and upwind of the parent updraft increases with the increasing downdraft top height.Vertical momentum budgets indicate that downward-oriented buoyancy due to the evaporational cooling of rainwater and precipitation drag mainly contribute to the occurrence of low-level downdrafts,and the midlevel and upper-level downdrafts originate due to precipitation drag and are strengthened by the downward-oriented,buoyancy-induced perturbation pressure gradient.The processes governing the downdrafts from the tropopause are different between the two experiments.More icy-type particles are produced and transported outward at upper levels in the lower-layer shear experiment,resulting in larger downward-oriented buoyancy due to the sublimational cooling of icy-type particles and contributing to the development/maintenance of the downdraft from the tropopause in that experiment.However,the downwardoriented perturbation pressure gradient leads to the development/maintenance of the downdraft from the tropopause in the upper-layer shear experiment.

Hyperbolic metamaterial using chiral molecules

We theoretically investigate the intra-band transitions in Mobius molecules.Due to the weak magnetic response,the relative permittivity is significantly modified by the presence of the medium while the relative permeability is not.We show that there is hyperbolic dispersion relation induced by the intra-band transitions because one of the eigen-values of permittivity possesses a different sign from the other two,while all three eigen-values of permeability are positive.We further demonstrate that the bandwidth of negative refraction is 0.165 eV for the H-polarized incident light,which is broader than the ones for inter-band transitions by 3 orders of magnitude.Moreover,the frequency domain has been shifted from ultra-violet to visible domain.Although there is negative refraction for the E-polarized incident light,the bandwidth is much narrower and depends on the incident angle.