^(12)C^(16)O_(2)分子位于1.57μm的饱和吸收光谱

本文展示了基于光梳锁频-光腔衰荡光谱装置测量的^(12)C^(16)O_(2)分子位于1.57μm附近的30012←00001振动带中转动量子数最高为68的共计37根振转跃迁的饱和吸收光谱,其频率确定至kHz水平;文献和CDSD2019数据库中的多普勒光谱确定的30012振动态的振转能级与本工作确定的数值存在超过1 MHz的偏差.

Energy-Efficient Traffic Offloading for RSMA-Based Hybrid Satellite Terrestrial Networks with Deep Reinforcement Learning

As the demands of massive connections and vast coverage rapidly grow in the next wireless communication networks, rate splitting multiple access(RSMA) is considered to be the new promising access scheme since it can provide higher efficiency with limited spectrum resources. In this paper, combining spectrum splitting with rate splitting, we propose to allocate resources with traffic offloading in hybrid satellite terrestrial networks. A novel deep reinforcement learning method is adopted to solve this challenging non-convex problem. However, the neverending learning process could prohibit its practical implementation. Therefore, we introduce the switch mechanism to avoid unnecessary learning. Additionally, the QoS constraint in the scheme can rule out unsuccessful transmission. The simulation results validates the energy efficiency performance and the convergence speed of the proposed algorithm.

Piezo1 expression in chondrocytes controls endochondral ossification and osteoarthritis development

Piezo proteins are mechanically activated ion channels,which are required for mechanosensing functions in a variety of cell types.While we and others have previously demonstrated that the expression of Piezo1 in osteoblast lineage cells is essential for boneanabolic processes,there was only suggestive evidence indicating a role of Piezo1 and/or Piezo2 in cartilage.Here we addressed the question if and how chondrocyte expression of the mechanosensitive proteins Piezo1 or Piezo2 controls physiological endochondral ossification and pathological osteoarthritis(OA)development.Mice with chondrocyte-specific inactivation of Piezo1(Piezo1^(Col2a1Cre)),but not of Piezo2,developed a near absence of trabecular bone below the chondrogenic growth plate postnatally.Moreover,all Piezo1^(Col2a1Cre) animals displayed multiple fractures of rib bones at 7 days of age,which were located close to the growth plates.While skeletal growth was only mildly affected in these mice,OA pathologies were markedly less pronounced compared to littermate controls at 60 weeks of age.Likewise,when OA was induced by anterior cruciate ligament transection,only the chondrocyte inactivation of Piezo1,not of Piezo2,resulted in attenuated articular cartilage degeneration.Importantly,osteophyte formation and maturation were also reduced in Piezo1^(Col2a1Cre) mice.We further observed increased Piezo1 protein abundance in cartilaginous zones of human osteophytes.Finally,we identified Ptgs2 and Ccn2 as potentially relevant Piezo1 downstream genes in chondrocytes.Collectively,our data do not only demonstrate that Piezo1 is a critical regulator of physiological and pathological endochondral ossification processes,but also suggest that Piezo1 antagonists may be established as a novel approach to limit osteophyte formation in OA.

Nitrate in the Changjiang diluted water:an isotopic evaluation on sources and reaction pathways

A cruise covering two transects in the Changjiang(Yangtze)estuary in July 2017 was conducted,aiming to explore the sources for riverine NOˉ3 and identify reactions involved in the NO_(3)^(-)transformations along the transport of the Changjiang diluted water(CDW).In the river water,NO_(3)^(-)was fundamentally contributed by chemical fertilizer leakage in the watershed according to isotope signals.Sewage discharge may also be significant on riverine NO_(3)^(-)inventory,while the isotope signal was masked by nitrification.Together with the transport of the CDW,NO_(3)^(-)production was observed in waters with low salinities(<20)and high turbidities.Nitrification resulted from the mineralization of riverine organic nitrogen;therefore,the high turbidity was linked to active production.In the outer plume,coupled with stratification,a significant decrease in NO_(3)^(-)concentration was observed in the surface water.In parallel,enrichment inδ^(15)N-NO_(3)^(-)andδ^(18)O-NO_(3)^(-)was found,indicating biological consumption by phytoplankton.The difference in the stratification intensity between two transects led to variations in NO_(3)^(-)concentrations and isotope compositions.In the benthic water,denitrification(sediment-water interface)and nitrification(bottom water)coexisted.Furthermore,accumulations of NH4+and dissolved organic nitrogen in the bottom water were observed,indicating that nitrification was constrained by oxidant(mainly dissolved oxygen)supplies.

Benthic microbial biogeography along the continental shelf shaped by substrates from the Changjiang River plume

Coastal zones are active reactors of continental material including that transported by rivers via a series of microbiota-mediated reactions. Nevertheless, current knowledge of the ecology and functioning of the microbiota in coastal areas affected by large riverine inputs remains insufficient on a global scale. Here, an investigation on sediment microbial composition, including taxonomy and metabolic network, as well as their relationship with major benthic reaction substrates, namely carbon, nitrogen, sulphur and phosphorus, was conducted in the continental shelf affected by the spread of the Changjiang River plume. Surface sediment samples(48 samples)were collected during March 2018, obtaining a mean Operational Taxonomic Units(OTUs) number of 3 341.Proteobacteria, Acidobacteria and Actinobacteria were abundant phyla in the studied sediments. Bray-Curtis distance analysis classified the 48 samples into 4 clusters(MG1 to MG4) at the phylum-level. MG1 and MG2 are found near the river mouth, receiving substantial land-derived particles from the Changjiang River runoff.Particle-attached microbes may be settled in these regions and influenced the observed sediment microbial diversity and biomass, e.g., increased Crenarchaeota relative abundance. The relative enrichment of these two groups in heterotrophic microbes further suggests a reliance of benthic microbiota on substrates with terrestrial origin, particularly specialized on processing sulphur-rich substrates. Regions MG3 and MG4 are located in the outer margin of the area affected by the Changjiang River plume, mainly fed by settling pelagic particles from phytoplankton. Compared to MG1 and MG2, a significant increase in the abundance of Thaumarcheota(phylumlevel) and Nitrosopumilus(genus-level) was found in MG3, suggesting nitrogen-related transformations as the key reactions to sustain microbial metabolism in this region. Coupled with the identified variations in the taxonomic composition, significant differences in the keystone taxa between MG1/MG2 and MG3/MG4 were identified via OTU co-occurrence analyses. A higher abundance of Actinobacteria, Thaumarchaeota and Acidobacteria in MG3 and MG4 reinforced the identified spatial variability in benthic metabolism and highlighted the significance of substrate inputs on the sediment microbial structure and biogeography.

氮掺杂石墨毡对水系醌基氧化还原液流电池性能的影响

电极的性能是实现水系醌基氧化还原液流电池(AQRFBs)高能量效率的关键。本文采用尿素水热反应对石墨毡(GF)进行改性,同时研究了水热反应时间对氮掺杂石墨毡表面官能团和结构的影响。利用扫描电子显微镜(SEM)、比表面积及孔隙度分析仪(BET)、拉曼光谱(Raman)和X射线光电子能谱(XPS)对改性电极的表面形貌、比表面积、碳缺陷、元素含量和表面官能团进行了表征。然后,通过循环伏安法、电化学阻抗谱和单电池循环对改性电极的电化学性能进行了研究。结果表明,氮掺杂提高了石墨毡的比表面积、亲水性和电导率。氮掺杂石墨毡(NGFs)具有优异的电化学催化活性和较低的电荷转移电阻。与GF相比,在100 mA·cm^(-2)时,电池负极使用NGF-6电极后,醌基氧化还原液流电池的能量效率提高了8.0%。

Microbiota of a seepage face at the mouth of a subterranean estuary:diversity,distribution and substrate dependence

Subterranean estuaries,i.e.,the mixing zone between terrestrial groundwater and recirculated seawater,host a wide range of microbiota.Here,field campaigns were conducted at the mouth of the subterranean estuary at the Sanggou Bay(Shandong Province,China)over four consecutive seasons at a seepage face(0−20 cm depth).The diversity of benthic microbiome was characterized via 16S rRNA gene sequencing and metagenomics,combined with physic-chemical parameters,e.g.,organic carbon,total nitrogen and sulfate contents in sediments.During spring,the dominant species were assigned to the phylum Proteobacteria.Important opportunistic species was assigned to Acidobacteria,Actinobacteria and Bacteroidetes.The key components were identified to be species of the genera Pseudoalteromonas,Colwellia and Sphingobium,indicating the involvement of sediment microbiota in the degradation of sedimentary organic carbon,particularly that of pelagic origin,e.g.,phytoplankton detritus and bivalve pseudo-feces.During spring,the microbial community was statistically similar along the depth profiles and among the three sampled stations.Similar spatial distributions were obtained in the remaining seasons.By contrast,the dominant species assemblages varied significantly among seasons,with key genera being Thioprofundum and Nitrosopumilus during summer and autumn and Thioprofundum and Ilumatobacter during winter.Network analysis revealed a seasonal shift in benthic nitrogen and sulfur metabolism associated with these variations in microbial community composition.Overall,our findings suggested that macro elements derived from pelagic inputs,particularly detrital phytoplankton,shaped the microbial community compositions at the seepage face,resulting in significant seasonal variations,while the influence of terrestrial materials transported by groundwater on the sediment microbiota at the seepage face found to be minor.

A comparison between high temperature catalytic and persulfate oxidation for the determination of total dissolved nitrogen in natural waters

Total dissolved nitrogen(TDN) is an important parameter for assessing the nutrient cycling and status of natural waters.The accurate determination of TDN in natural waters is essential for assessing its contents and distinguishing different forms of nitrogen in the water.The TDN in various systems has been largely documented,and the concentrations of TDN are usually obtained using high-temperature catalytic(HTC) or persulfate oxidation(PO).However,the accuracy of these methods and their suitability for all types of natural waters are still unclear.To explore both methods in-depth,assorted samples were tested,including eight solutions composed of nitrogen-containing compounds(3 dissolved inorganic nitrogen fractions:NO_(3)^(-),NO_(2)^(-)and NH_(4)^(+);5 organic compounds:EDTA-2Na,vitamin B1,vitamin B12,amino acids,and urea) and 105 natural waters which were collected from an open ocean(Northwest Pacific Ocean,28),a marginal sea(Yellow Sea,34),an estuary(Huanghe River mouth,31),rivers(Huanghe River,4;Licun River,4),and precipitations(4 samples).The results showed that heterocycles and molecular dimensions had certain effects on the oxidation efficiency of the PO method but had little effect on HTC.There was no significant difference between the two methods for natural waters,but HTC was more suitable for deep-sea samples with low TDN concentrations(less than 10 μmol/L) and low organic activity.Overall,HTC has a relatively simple measurement process,a high degree of automation,and low error.Therefore,HTC can be recommended to determine the TDN of samples in freshwater and seawater.

The extracellular secretion of miR-1825 wrapped by exosomes increases CLEC5A expression:A potential oncogenic mechanism in ovarian cancer

Background:Ovarian cancer(OC)is a leading cause of gynecological cancer-linked deaths worldwide.Exosomal miR-1825 and its target gene C-type lectin domain family 5 member A(CLEC5A)are associated with tumorigenesis in cancers that was further probed.Methods:Exosomal miR-1825 expression in exosomes and its impact on overall survival(OS)prediction were determined using Gene Expression Omnibus(GEO)and The Cancer Genome Atlas(TCGA)data.Target genes of miR-1825 were searched in five prediction databases and prognostically significant differentially expressed genes were identified.Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses were carried out.The ability of CLEC5A to predict OS was evaluated using univariate and multivariate Cox regression analyses and Kaplan-Meier curves.The CLEC5A expression pattern in OC was validated using immunohistochemistry.The CIBERSORT algorithm was used to compare the immune cell landscape,and the results were validated in a GEO cohort.Finally,the predicted half maximal inhibitory concentration(IC50)values for five commonly used chemotherapy agents were also compared.Results:MiR-1825 level was higher in exosomes derived from OC cells and served as a tumor suppressor.The CLEC5A gene was found to be a target of miR-1825,the upregulation of which was correlated with a poor prognosis.M2 macrophage infiltration was significantly enhanced in the CLEC5A high expression group,while T follicular helper cell infiltration was reduced in it.While the predicted IC50 for cisplatin and doxorubicin was higher in the CLEC5A high expression group,that of docetaxel,gemcitabine,and paclitaxel was lower.Conclusion:MiR-1825,a promising OC biomarker,may promote OC progression by increasing CLEC5A expression via exosome-mediated efflux from tumor cells.

清代盛京内务府档案房职能研究——基于辽宁省档案馆藏《黑图档》的考察

文章选取辽宁省档案馆藏《黑图档》作为研究的依据,深入剖析其中盛京内务府档案房与其他部门的往来公文及存查档,进一步分析清代地方档案馆的工作内容。通过梳理档案可以发现,档案房的具体职责主要体现为五个方面:抄写、保管、汇总、印务及移交等文档工作。

整合与创新—浙江省“美丽乡村”建设规划探析

本文通过新农村建设发展趋势分析,指明浙江省当前美丽乡村建设规划是新农村规划的“升级版”,其工作具有综合性、地方性及操作性特点。操作层面上存在技术依据缺失和管理机制失效两大问题,于此提出规划整合和机制创新两大措施,以期解决问题。

Gender and metabolic differences of gallstone diseases

AIM:To investigate the risk factors for gallstone disease in the general population of Chengdu,China. METHODS:This study was conducted at the West China Hospital.Subjects who received a physical examination at this hospital between January and December 2007 were included.Body mass index,blood pressure,fasting plasma glucose,serum lipid and lipoproteins concentrations were analyzed.Gallstone disease was diagnosed by ultrasound or on the basis of a history of cholecystectomy because of gallstone disease.Unconditional logistic regression analysis was used to investigate the risk factors for gallstone disease,and the Chi-square test was used to analyze differences in the incidence of metabolic disorders between subjects with and without gallstone disease. RESULTS:A total of 3573 people were included, 10.7%(384/3573)of whom had gallstone diseases. Multiple logistic regression analysis indicated that the incidence of gallstone disease in subjects aged 40-64 or≥65 years was significantly different from that in those aged 18-39 years(P<0.05);the incidence was higher in women than in men(P<0.05).In men,a high level of fasting plasma glucose was obvious in gallstone disease(P<0.05),and in women, hypertriglyceridemia or obesity were significant in gallstone disease(P<0.05).

PA66/PA6I6T共混物非等温结晶动力学及性能

将PA66与PA6I6T以不同配比进行熔融共混,通过差示扫描量热分析对所制备的尼龙66(PA66)与半芳香尼龙(PA6I6T)共混物在不同降温速率下的非等温结晶行为进行了研究。利用Jeziorny法及Mo方法对共混物的非等温结晶动力学数据进行了分析,并采用Kissinger方法计算了共混体系的结晶活化能;考察了PA6I6T含量对共混物力学性能、耐热性及加工流动性的影响。研究发现,PA66与PA6I6T具有良好的相容性,少量的PA6I6T会促进PA66的结晶,随着PA6I6T含量的进一步增加,PA66的结晶速率及结晶度呈下降趋势,PA66的结晶活化能的绝对值随PA6I6T含量的增加表现为先增大后减小。共混物的拉伸强度和冲击强度随PA6I6T含量的增加而增加,其中拉伸强度在PA6I6T达到一定含量后趋于平缓。PA6I6T的引入提高了共混物的耐热性和热稳定性,但加工流动性较纯PA66材料有一定程度降低。

3D功能模型在口腔正畸中的应用现状与研究进展

在正畸临床工作中,牙颌模型是患者初始信息和疗程记录的良好载体,也是诊断分析的重要资料。在治疗过程中,可通过研究模型来了解当前的治疗情况及矫治进展,并及时调整治疗方案,达到最佳疗效。石膏模型存在固化时间长、边缘不清楚、取模变性等缺点,难以快速准确地测量数据并对治疗结果的预测存在一定的局限性。伴随着科学技术的不断发展,石膏模型已很难满足正畸医师的需求。3D功能模型技术的发展为数字化时代下的正畸治疗带来了巨大变化。3D功能模型技术广泛应用于数字化建档、三维诊断及治疗方案的辅助设计、正畸矫治、正畸材料设备制造、科研教学等。3D功能模型技术应用带动了口腔正畸的发展,该文就3D功能模型在口腔正畸领域的应用进行综述。

The role of sphingosine-1-phosphate in bone remodeling and osteoporosis

Osteoporosis is a systemic bone disease that affects more than 200 million people worldwide and is caused by the disruption of the equilibrium between osteoclastic bone resorption and osteoblastic bone formation. Sphingosine-1-phosphate(S1 P) is a natural,bioactive sphingolipid that has been shown to play a major role in cardiovascular and immunological pathologies by regulating biological and cellular processes, including migration, differentiation, proliferation and survival. Recent studies also suggest a central role for S1 P in bone diseases, including osteoporosis;however, the effects of S1 P, particularly in bone metabolism, remain to be further elucidated. In this review, we summarize the available literature on the role of S1 P in bone metabolism with a focus on osteoporosis. On the cellular level, S1 P acts as an osteoclast-osteoblast coupling factor to promote osteoblast proliferation and bone formation. Moreover, the recruitment of osteoclast precursors to resorption sites is regulated by the interplay of S1 P gradients and S1 P receptor expression. From a clinical perspective, increasing evidence suggests that systemically elevated S1 P blood levels may serve as an independent risk factor for osteoporosis-related fractures. Taken together, S1 P signaling is a potential therapeutic target and may serve as a novel biomarker in patients with systemic bone disease.

Carvedilol protected diabetic rat hearts via reducing oxidative stress

Oxidative stress plays a dominant role in the pathogenesis of diabetes mellitus. Bcl-2 gene has close connection with antioxidant stress destruction in many diseases including diabetes. Carvedilol, an adrenoceptor blocker, also has antioxidant properties. To study the effect of carvedilol on the antioxidant status in diabetic hearts, we investigated carvedilol-administrated healthy and streptozotocin-induced diabetic rats. After small and large dosage carvedilol-administered for 5 weeks, hemodynamic parameters, the levels of malondialdehyde, activities of antioxidant enzymes and expression of Bcl-2 mRNA in the cardiac tissues were measured. The diabetic rats not only had cardiac disfunction, weaker activities of antioxidant enzymes, but also showed lower expression of Bcl-2. Carvedilol treatment increased activities of antioxidant enzymes and expression of Bcl-2 in healthy rats as well as diabetic rats. These results indicated that carvedilol partly improves cardiac function via its antioxidant properties in diabetic rats.

Hierarchical Bimetallic Selenides CoSe_(2)–MoSe_(2)/rGO for Sodium/Potassium-Ion Batteries Anode: Insights into the Intercalation and Conversion Mechanism

As anode materials for high-performance sodium-ion batteries and potassium-ion batteries,bimetallic selenides have attracted great concern due to their relatively high electrical conductivity and electrochemical activity.However,the formidable challenge in the reaction process is the large volume change,leading to the structural collapse of material,and eventually the decline in electrochemical performance.Herein,a composite of hierarchical CoSe_(2)–MoSe_(2) tubes anchored on reduced graphene oxide nanosheets(CoSe_(2)–MoSe_(2)/rGO)is designed by an in situ hydrothermal selenization treatment.Benefiting from the synergistic effects between CoSe_(2) and MoSe_(2),unique hierarchical structure,and effective reduced graphene oxide coating,the CoSe_(2)–MoSe_(2)/rGO exhibited improved reaction kinetics and structural stability,and thus good electrochemical properties.A combination mechanism of intercalation and conversion of CoSe_(2)–MoSe_(2)/rGO by forming NaxCoSe_(2) and Mo_(15)Se_(19) as intermediate states is put forward on the basis of in situ and ex situ XRD analyses.

Folding beam-type piezoelectric phononic crystal with low-frequency and broad band gap

A folding beam-type piezoelectric phononic crystal model is proposed to isolate vibration. Two piezoelectric bimorphs are joined by two masses as a folding structure to comprise each unit cell of the piezoelectric phononic crystal. Each bimorph is connected independently by a resistive-inductive resonant shunting circuit. The folding structure extends the propagation path of elastic waves, while its structure size remains quite small. Propagation of coupled extension-flexural elastic waves is studied by the classical laminated beam theory and transfer matrix method. The theoretical model is further verified with the finite element method(FEM). The effects of geometrical and circuit parameters on the band gaps are analyzed. With only 4 unit cells, the folding beam-type piezoelectric phononic crystal generates two Bragg band gaps of 369 Hz to1 687 Hz and 2 127 Hz to 4 000 Hz. In addition, between these two Bragg band gaps, a locally resonant band gap is induced by resonant shunting circuits. Appropriate circuit parameters are used to join these two Bragg band gaps by the locally resonant band gap.Thus, a low-frequency and broad band gap of 369 Hz to 4 000 Hz is obtained.

Diffusion tensor imaging with multiple diffusion-weighted gradient directions

Diffusion tensor MRI （DT-MRI or DTI） is emerging as an important non-invasive technology for elucidating intemal brain structures. It has recently been utilized to diagnose a series of diseases that affect the integrity of neural systems to provide a basis for neuroregenerative studies. Results from the present study suggested that neural tissue is reconstructed with multiple diffusion-weighted gradient directions DTI, which varies from traditional imaging methods that utilize 6 gradient directions. Simultaneously, the diffusion tensor matrix is obtained by multiple linear regressions from an equation of echo signal intensity. The condition number value and standard deviation of fractional anisotropy for each scheme can be used to evaluate image quality. Results demonstrated that increasing gradient direction to some extent resulted in improved effects. Therefore, the traditional 6 and 15 directions should not be considered optimal scan protocols for clinical DTI application. In a scheme with 20 directions, the condition number and standard deviation of fractional anisotropy of the encoding gradients matrix were significantly reduced, and resulted in more clearly and accurately displayed neural tissue. Results demonstrated that the scheme with 20 diffusion gradient directions provided better accuracy of structural renderings and could be an optimal scan protocol for clinical DTI application.

Electromagnetic Wave Propagation into Fresh Water

Wireless communications from air to fresh water are studied here. Our analysis relies on plane wave propagation mod-els. Specifically, the transmission loss and propagation loss of RF waves penetrating into fresh water are calculated for various propagation depths. Even though RF wireless communications are not well suited for seawater due to its high attenuation, our paper illustrates that RF communications from air to fresh water are possible. Finally, this work de-rives the optimum frequencies, which provide minimum attenuation and maximum propagation depth, for RF commu-nications from air to fresh water.