通过碳点从共价三嗪框架中提取光生空穴用于光合作用产过氧化氢

过氧化氢(H_(2)O_(2))是一种多功能氧化剂,利用地球上丰富的水和氧合成过氧化氢是解决能源危机和环境修复的一种有前景的方法.共价三嗪框架(CTFs)因具有独特的稳定结构以及π共轭sp^(2)碳结构上功能基团的高可设计性,其作为光催化剂而备受关注.然而,由于共轭键的可逆性较差,极大地影响了电荷的分离和转移.为了提高载流子分离效率,目前的策略主要为开发高结晶结构或在CTFs骨架中加入具有不同电离势和电子亲和力的供电子和接受电子单元,但催化性能和太阳能化学转化(SCC)效率仍然低于预期.碳点(CDs)具有类分子特性,可以通过表面接触或结合改变材料的微观结构和物理性能,起到调控光生电荷行为的作用.因而,本文把CDs引入到CTFs分子中,使其充当电荷分离器,提升光生载流子的利用效率.本文提出一种可扩展的方法,使1,4-二氰苯(DCB)、CDs和碱金属盐在溶液中发生选择性吸附反应,去除溶剂后制备出预混物,然后再以CF_(3)SO_(3)H为催化剂,在空气氛围内直接加热预混物至250℃并反应8 h,获得具有高结晶CTFs与CDs的复合光催化剂(CDs@CTFs).透射电镜、X射线光电子能谱(XPS)等结果证明了CDs引入到CTFs插层中.粉末X射线衍射结果表明,适量的CDs可以提高CTFs的结晶度.紫外-可见吸收谱表明CDs的引入扩大了可见光的吸收范围.Zeta电位、光致发光光谱等结果表明,二价和多价阳离子同时与两个或两个以上的CDs相互作用,导致其溶胶溶液的不稳定性和表面电子态的改变,影响了光催化剂性能.XPS、红外光谱、热重分析(TGA)等表征结果表明CDs表面羧基的H+离子可能被碱金属离子取代,从而调节表面电荷分布,促进电荷分离和转移.电荷牺牲实验、原位漫反射红外傅立叶变换光谱和电子顺磁共振谱测试结果表明,CDs@CTFs可以实现氧还原反应和水氧化反应双通道产H_(2)O_(2).通过使用已知的电子受体和电子供体来识别CDs和CTFs之间的电荷转移过程,并结合对空穴传输层器件的暗I-V曲线测试结果,揭示了CDs具有空穴存储功能.所制光催化剂的H_(2)O_(2)产率为2464μmolh^(-1)g^(-1),全光谱光化学转化效率为0.9%,500 nm的表观量子产率为13%,超过了目前报道的大多数光催化剂.结合理论分析结果表明,CDs可以作为空穴提取剂有效地驱动激子解离,并为水氧化反应提供活性位点;研究发现碱金属离子在合成过程中与CDs表面的羧酸基团相互作用,增强对CTFs的空穴提取能力,加速光催化生成H_(2)O_(2).此外,所制光催化剂在自然阳光下可连续工作产H_(2)O_(2),且光催化性能经过100 d循环使用仍表现出高的稳定性.综上所述,本文开发了一种简便且可扩展的方法,将CDs引入到CTFs中,以实现高效的光催化产H_(2)O_(2).CDs通过其界面产生的内电场从CTFs中提取光生空穴,并在CTFs上充当空穴存储层.此外,碱金属离子能显著调节内部电场强度,使CDs@CTFs具有更显著的光催化性能.本工作揭示了一种新的设计策略来调控有机共轭聚合物中的载流子分离和迁移.

陇东地区石油化工生产中采用液化分离法捕集烟道中二氧化碳的研究

在全球气候变暖的大趋势下,为积极应对气候变化挑战,我国承诺于2060年全社会进入低碳发展模式。因此大力研发节能减排技术成为我国工业企业尤其是石油、煤炭、化工等重污染领域的发展的首要技术支撑。液化分离法作为碳捕集与封存技术中最具有研究价值和推广价值的技术也成为近年来各大企业和研究机构的宠儿,我们根据陇东地区气候和地质特点,在庆阳市当地企业生产现状的基础上设计优化了液化分离法捕集二氧化碳流程。

Theoretical study of the ionospheric dynamo region inside the South Atlantic Anomaly

The South Atlantic Anomaly(SAA)is a region where the geomagnetic field is significantly lower than that of the surrounding area.On the basis of the models of CHAOS-7.8,Mass Spectrometer Incoherent Scatter Model(NRLMSISE-00),and International Reference Ionosphere 2016(IRI-2016),we theoretically investigated the lower and upper boundaries of the ionospheric dynamo region inside the SAA.In the ionospheric dynamo region,electrons are coupled with magnetic field lines,whereas ions are decoupled from magnetic field lines.Our results showed that the ionospheric dynamo region inside the SAA is higher and larger than that outside the SAA.We also studied the boundary variations of the dynamo region inside the SAA depending on the seasons and solar activities.We found that the dynamo region inside the SAA is the highest and largest in the summer of the southern hemisphere at solar maximum.The larger and higher altitude range of the ionospheric dynamo region in the SAA can contribute to the stronger ionospheric currents in this region.

Dielectric loss enhancement induced by the microstructure of CoFe_(2)O_(4) foam to realize broadband electromagnetic wave absorption

CoFe_(2)O_(4)has been widely used for electromagnetic wave absorption owing to its high Snoek limit,high anisotropy,and suitable saturation magnetization;however,its inherent shortcomings,including low dielectric loss,high density,and magnetic agglomeration,limit its application as an ideal absorbent.This study investigated a microstructure regulation strategy to mitigate the inherent disadvantages of pristine CoFe_(2)O_(4)synthesized via a sol–gel auto-combustion method.A series of CoFe_(2)O_(4)foams(S0.5,S1.0,and S1.5,corresponding to foams with citric acid(CA)-to-Fe(NO_(3))_(3)·9H_(2)O molar ratios of 0.5,1.0,and 1.5,respectively)with two-dimensional(2D)curved surfaces were obtained through the adjustment of CA-to-Fe^(3+)ratio,and the electromagnetic parameters were adjusted through morphology regulation.Owing to the appropriate impedance matching and conductance loss provided by moderate complex permittivity,the effective absorption bandwidth(EAB)of S0.5 was as high as 7.3 GHz,exceeding those of most CoFe_(2)O_(4)-based absorbents.Moreover,the EAB of S1.5 reached 5.0 GHz(8.9–13.9 GHz),covering most of the X band,owing to the intense polarization provided by lattice defects and the heterogeneous interface.The three-dimensional(3D)foam structure circumvented the high density and magnetic agglomeration issues of CoFe_(2)O_(4)nanoparticles,and the good conductivity of 2D curved surfaces could effectively elevate the complex permittivity to ameliorate the dielectric loss of pure CoFe_(2)O_(4).This study provides a novel idea for the theoretical design and practical production of lightweight and broadband pure ferrites.

EPAS1 prevents telomeric damage-induced senescence by enhancing transcription of TRF1,TRF2,and RAD50

Telomeres are nucleoprotein structures located at the end of each chromosome,which function in terminal protection and genomic stability.Telomeric damage is closely related to replicative senescence in vitro and physical aging in vivo.As relatively long-lived mammals based on body size,bats display unique telomeric patterns,including the upregulation of genes involved in alternative lengthening of telomeres(ALT),DNA repair,and DNA replication.At present,however,the relevant molecular mechanisms remain unclear.In this study,we performed cross-species comparison and identified EPAS1,a well-defined oxygen response gene,as a key telomeric protector in bat fibroblasts.Bat fibroblasts showed high expression of EPAS1,which enhanced the transcription of shelterin components TRF1 and TRF2,as well as DNA repair factor RAD50,conferring bat fibroblasts with resistance to senescence during long-term consecutive expansion.Based on a human single-cell transcriptome atlas,we found that EPAS1 was predominantly expressed in the human pulmonary endothelial cell subpopulation.Using in vitro-cultured human pulmonary endothelial cells,we confirmed the functional and mechanistic conservation of EPAS1 in telomeric protection between bats and humans.In addition,the EPAS1 agonist M1001 was shown to be a protective compound against bleomycin-induced pulmonary telomeric damage and senescence.In conclusion,we identified a potential mechanism for regulating telomere stability in human pulmonary diseases associated with aging,drawing insights from the longevity of bats.

Flocculation Efficiency in Taylor-Couette Flow

Velocity field data were acquired for Taylor-Couette flow in the annulus gap between a rotating inner cylinder and a fixed concentric outer cylinder by particle image velocimetry. The flocculation efficiencies were also obtained in the same Taylor-Couette flow under the conditions corresponding to the velocity field measurement. It was shown that the flocculation efficiencies reach the maximum values due to the closed vortices in WVF and their contraction and expansion with time, but out of WVF range, the comparatively low flocculation efficiencies were obtained due to the no-closed vortices connected with each other.

3D conformal radiotherapy combined with transcatheter arterial chemoembolization for hepatocellular carcinoma

AIM:To compare transcatheter arterial chemoembolization(TACE)and 3D conformal radiotherapy(3D-CRT)with TACE monotherapy in hepatocellular carcinoma(HCC).METHODS:We searched all the eligible studies from the Cochrane Library,Pub Med,Medline,Embase,and CNKI.The meta-analysis was performed to assess the survival benefit,tumor response,and the decline inα-fetoprotein(AFP)level.According to the heterogeneity of the studies,pooled OR with 95%CI were calculated using the fixed-effects or random-effects model.An observed OR>1 indicated that the addition of 3D-CRT to TACE offered survival benefits to patients that could be considered statistically significant.Statistical analyses were performed using Review Manager Software.RESULTS:Ten studies met the criteria to perform a meta-analysis including 908 HCC participants,with 400patients in the TACE/3D-CRT combination group and508 in the TACE alone group.TACE combined with 3DCRT significantly improved 1-,2-and 3-year overall survival compared with TACE monotherapy(OR=1.87,95%CI:1.37-2.55,P<0.0001),(OR=2.38,95%CI:1.78-3.17,P<0.00001)and(OR=2.97,95%CI:2.10-4.21,P<0.00001).In addition,TACE plus 3DCRT was associated with a higher tumor response(complete remission and partial remission)(OR=3.81;95%CI:2.70-5.37;P<0.00001),and decline rates of AFP level(OR=3.24,95%CI:2.09-5.02,P<0.00001).CONCLUSION:This meta-analysis demonstrated that TACE combined with 3D-CRT was better than TACE monotherapy for patients with HCC,which needs to be confirmed by large multicenter trials.

Focal choroidal excavation complicated with choroidal neovascularization in young and middle aged patients

AIM: To investigate the clinical and optical coherence tomography(OCT) features of focal choroidal excavation(FCE) complicated with choroidal neovascularization(CNV) in young and middle aged patients. METHODS: We performed a retrospective review of 26 patients with FCE accompanied by CNV. All patients underwent a complete ophthalmic examination. We analyzed the clinical characteristics of patients, focusing on the spectral-domain OCT features. All patients received intravitreal injection of anti-vascular endothelial growth factor(anti-VEGF) agents. And we assessed the changes of central retinal thickness and best-corrected visual acuity(BCVA) after anti-VEGF therapy. RESULTS: The mean age of 26 patients was 35.5±7.3 y(range, 21-48 y). Of the 26 FCE lesions, 11 were located subfoveal, 6 were parafoveal, and 9 were extrafoveal. The mean FCE depth was 129.8±50.3 μm, and the mean width was 901.3±306.0 μm. The FCE depth was correlated positively with the width, but not correlated with age or refractive error. CNV was located within the excavation(19 eyes) or adjacent to the excavation(7 eyes). After anti-VEGF therapy, the central retinal thickness was significantly reduced and the BCVA was significantly improved. In the absorption process of subretinal fluid, we found that the fluid in the excavations needed to be absorbed at the last. A small amount of residual fluid could still be seen in a few deep excavations even after a longterm follow-up.CONCLUSION: FCE may be an important reason to cause CNV. Especially in young patients with idiopathic CNV, we should pay attention to the use of OCT to check the presence of FCE. Anti-VEGF therapy is generally effective for CNV associated with FCE.

绿色化学在高职化学教育中的教学探讨

绿色化学是随着世界各国政府单纯追逐经济效率到兼顾生态保护这一趋势而产生的,在当下,绿色化学已经成为化学工业必然的发展之路。而高职院校化学教育强调的是实践化的化学,即重视化学工业的应用,因而,在高职院校的化学教育实施绿色化学的教育,培养师生形成绿色化学的思维,对化工产业的改革及生态保护都有积极的意义,重点从绿色化学在高职化学教育中的教学策略、教学原则出发,提供可操作的意见。

The correlation between ultrasonographic findings and the Lysholm scores in knee osteoarthritis

Objective:To analyze the correlation between ultrasonographic findings and Lysholm scores in knee osteoarthritis.Methods:This cross-sectional observational study included 77 cases of knee osteoarthritis examined from February to December in 2015.There were 66 females and 11 males,with an average age of 57.39 (6.41) years,single or bilateral knee pain and limitation of mobility,and an average course of disease of 13.60 (3.00) months.Multiple regression equations were applied in a linear regression analysis to assess the correlation between ultrasound findings and Lysholm scores.Results:The ultrasonographic findings of joint effusion,synovial hypertrophy,protrusion of the medial meniscus (MMP),and inflammation of subpatellar fat pad were significantly correlated with the Lysholm scores (all P <.05).In contrast,there was no association between the ultrasonographic findings of Baker's cyst or patellar ligament lesion and the Lysholm scores (both P >.05).Conclusion:Musculoskeletal ultrasound can better detect the pathological changes of soft tissue in the knee,mainly including synovial hypertrophy,joint effusion,and MMP in comparison with those by plain radiology.After statistical analysis,it is indicated that ultrasonographic findings of synovial hypertrophy was possibly associated with joint locking,joint effusion with supporting,MMP with squatting,and inflammation of subpatellar fat pad with squatting and locking.

浅析探究式教学法在高职基础化学教学中的应用

高职院校的基础化学教学方式随着我国教育改革的不断深化也发生了较为巨大的变化,探究式教学法的应用就是其中之一,本文采用探究式教学法,对高职院校基础化学传统教学模式中存在的问题进行了改进,并且获得了较为显著的效果。

洋岛玄武岩中的熔体包裹体揭示地球深部氯循环

地球深部与表层间挥发性元素的交换一直是重要的地球科学问题.来自海水的挥发分通过热液蚀变作用进入大洋地壳,之后通过洋壳的俯冲作用进入上地幔.但是这些挥发分是否能够被带入更深的下地幔目前依然不清楚。

A simple new technique for the induction of residual posterior vitreous cortex removal and membrane peeling

AIM:To describe a quick,cost-effective alternative to using a scraper to remove the residual posterior vitreous cortex and create an inner limiting membrane(ILM)flap during vitrectomy.METHODS:The surgical technique and a retrospective interventional single-center series of cases were described.A hook was made on the tip of a conventional syringe needle(outer diameter,0.6 mm;23 gauge)by bending the needle against a plate.We used this hook to remove the residual posterior vitreous cortex and create an ILM flap during vitrectomy.The efficacy and safety of using this instrument in ophthalmological procedures for a variety of vitreoretinal disorders were evaluated.RESULTS:The hook was effective for removing focal or diffuse residual posterior vitreous cortex in eyes with rhegmatogenous retinal detachment,proliferative diabetic retinopathy,and pathological myopia.It was also successfully used to make a free edge of the ILM and help strip the epiretinal membrane.There were no serious complications associated with using the hook in delicate ophthalmological procedures.CONCLUSION:The hook,made by bending a conventional needle,is a simple and cost-effective instrument for removing residual posterior vitreous vortex and to create epiretinal and ILM flaps during vitrectomy in eyes with various vitreoretinal diseases.

Effect of polysaccharide fractions from Fortunella margarita on the fecal microbiota of mice and SCFA production in vitro

Fortunella margarita polysaccharides(FMPS)are composed of 4 polysaccharide fragments,namely mannogalactoglucan,galactoglucan,glucan and arabinoglucan.This study investigated the in vitro fermentation of FMPS fractions and their effect on the fecal microbiota of mice and short chain fatty acids(SCFAs)production.The results showed that the structure of the fecal microbiota was changed after FMPS fermentation.At the phylum level,the polysaccharide fractions reduced the relative abundance of Bacteroidetes compared with the inulin group.At the genus level,the polysaccharide fractions increased the abundance of Lactobacillus,and decreased the abundance of Granulicatella,Proteus and Rummeliibacillus.Polysaccharide fractions could promote the proliferation of beneficial bacteria(Lactobacillus),and decreased harmful bacteria(Granulicatella,Proteus,Rummeliibacillus and Serratia).Furthermore,there was a significant distinction in the genus level flora processed by different polysaccharide fractions,especially mannogalactoglucan.Polysaccharide fractions showed potential prebiotic effects,with mannogalactoglucan,in particular,promoting proliferation of SCFA-producing bacteria.SCFAs were regulated by monosaccharide composition,molecular weight of the FMPS fractions,and the composition of the fecal bacteria.Polysaccharide fractions could modulate metabolic function of the fecal microbiota,altering the levels of SCFAs.These results suggested that FMPS are important functional components in gut health,especially mannogalactoglucan.

The current practice and future promise of integration of exercise science and medicine in China

With an increasing proportion of sedentary lifestyle related chronic diseases,an efficient way to help fight the growing world epidemic of non-communicable diseases(NCDs)and promote public health in a fast-changing world is urgently needed.Exercise and medicine science have played an important role in prevention and control of NCDs.However,the current status and future development directions regarding the integration of exercise science and medicine(IESM)in China have not been well discussed.During 2017 Belt and Road Initiative Global Health International Congress&2017 Chinese Preventive Medicine Association-Chinese Society on Global Health Annual Meeting,Xi’an Jiaotong University Global Health Institute,and the Integration of Sport and Medicine Innovation Research Center,China Institute of Sport Science organized the IESM Forum on September 27.Six leaders and experts from China and abroad presented excellent research reports in the IESM Forum from several aspects.Experts reached a consensus at the end of their discussions that,in the near future,the IESM will be a key part of a sustainable health care system and as such should contribute to prosperity in China and around the world.However,compared with European,American and Japanese universities,the development of the IESM in China is in its early stages with huge development potential.

An ICME impact on the Martian hydrogen corona

The Martian hydrogen exosphere extends out of the bow shock, forming a "hydrogen corona". The solar wind interacts directly with the hydrogen corona. During an ICME event on 7 March 2015, the SWIA instrument onboard Mars Atmosphere and Volatile Evolution mission (MAVEN) observed that the pick-up H+ fluxes in upstream solar wind were enhanced. Also increased were the penetrating H+ fluxes in the Martian atmosphere. Quantitatively, these penetrating H+ fluxes cannot increase by a factor of 5 simply due to a factor of 3 increase in the solar wind density, suggesting that the increased abundance of exospheric hydrogen upstream of the bow shock was a consequence of the passage of the ICME. A denser outer hydrogen corona at high altitudes suggests that the expansion of the neutral atmosphere was caused by the ICME. The excited and heated hydrogen exosphere probably indicates an elevated hydrogen escape rate during an ICME.

跨学科项目式教学与校企合作联合教学融合探讨

基于石油工程技术专业基础课程《钻井液使用与维护》的教学改革要求,将企业资源和学校的师资力量有机结合,探索更加符合大专院校学生学习特点的教学新方式。以跨学科项目式教学模式为基础手段结合校企合作企业资源增强学生实际操作水平和职业技能,拓宽就业面,提升教学质量,培养企业需求的高素质创新型技术人才。

探究式教学方法下高职基础化学实验室管理改革

随着基础化学课程中探究式教学方法的融入,实验课程的授课方式也随之发生重大改变,原有的实验室管理方法已无法满足新的课堂需求,在基础化学实验室现有条件下,为适应新的教学手段和课堂模式,对实验室管理方法和手段的创新与改革方面进行探讨。

Carbon dots-incorporated CuSeO_(3)rationally regulates activity and selectivity of the hydrogen species via light-converted electrons

The chemoselective hydrogenation of structurally diverse nitroaromatics is a challenging process.Generally,catalyst activity tends to decrease when excellent selectivity is guaranteed.We here present a novel photocatalyst combining amino-functionalized carbon dots(N-CDs)with copper selenite nanoparticles(N-CDs@CuSeO_(3))for simultaneously improving selectivity and activity.Under visible light irradiation,the prepared N-CDs@CuSeO_(3)exhibits 100%catalytic selectivity for the formation of 4-aminostyrene at full conversion of 4-nitrostyrene in aqueous solvent within a few minutes.Such excellent photocatalytic performance is mainly attributed to the precise control of the hydrogen species released from the ammonia borane by means of light-converted electrons upon N-CDs@CuSeO_(3).Besides,the defect states at the interface of N-CDs and CuSeO_(3)enable holes to be trapped for promoting separation and transfer of photogenerated charges,allowing more hydrogen species to participate in catalytic reaction.

Wide‑field swept‑source OCT angiography of the periarterial capillary‑free zone before and after anti‑VEGF therapy for branch retinal vein occlusion

Background:The aim of the study was to investigate the changes in the periarterial capillary-free zone(paCFZ)after anti-vascular endothelial growth factor(VEGF)therapy in patients with branch retinal vein occlusion(BRVO)by widefield swept-source optical coherence tomography angiography(SS-OCTA)and assess their associations with clinical outcomes.Methods:In this retrospective observational study of 54 treatment-naive BRVO patients with macular edema,we reviewed the findings of 12×12 mm^(2)SS-OCTA at baseline,3,6,and 12 months after intravitreal ranibizumab injections.The paCFZ and major retinal artery areas were measured on SS-OCTA images.The paCFZ area to artery area(P/A)ratio was calculated.Results:The paCFZ areas and P/A ratios of first-and second-order arteries were significantly greater in BRVO eyes than in contralateral eyes(all P<0.01),but there were no differences in the first-and second-order artery areas(P=0.20 and 0.25,respectively).The paCFZ areas and P/A ratios decreased significantly at 3,6,and 12 months after anti-VEGF therapy(all P<0.01).The baseline P/A ratio was significantly correlated with the baseline best-corrected visual acuity(BCVA),central retinal thickness,and their improvements at 3,6,and 12 months(all P<0.05).Baseline BCVA and P/A ratios of first-and second-order arteries were independently associated with the final BCVA in multivariate linear regression.Conclusions:Wide-field SS-OCTA shows that anti-VEGF therapy can lead to a significant improvement in the paCFZ parameters in BRVO.Smaller baseline P/A ratios on SS-OCTA tend to predict better visual outcomes at 12 months after anti-VEGF therapy.