Research on batch multielement rapid quantitative analysis based on the standard curve-assisted calibration-free laserinduced breakdown spectroscopy method

This study proposes a batch rapid quantitative analysis method for multiple elements by combining the advantages of standard curve(SC)and calibration-free laser-induced breakdown spectroscopy(CF-LIBS)technology to achieve synchronous,rapid,and accurate measurement of elements in a large number of samples,namely,SC-assisted CF-LIBS.Al alloy standard samples,divided into calibration and test samples,were applied to validate the proposed method.SC was built based on the characteristic line of Pb and Cr in the calibration sample,and the contents of Pb and Cr in the test sample were calculated with relative errors of 6%and 4%,respectively.SC built using Cr with multiple characteristic lines yielded better calculation results.The relative contents of ten elements in the test sample were calculated using CF-LIBS.Subsequently,the SC-assisted CF-LIBS was executed,with the majority of the calculation relative errors falling within the range of 2%-5%.Finally,the Al and Na contents of the Al alloy were predicted.The results demonstrate that it effectively enables the rapid and accurate quantitative analysis of multiple elements after a single-element SC analysis of the tested samples.Furthermore,this quantitative analysis method was successfully applied to soil and Astragalus samples,realizing an accurate calculation of the contents of multiple elements.Thus,it is important to advance the LIBS quantitative analysis and its related applications.

Analysis of CLARANS Algorithm for Weather Data Based on Spark

With the rapid development of technology,processing the explosive growth of meteorological data on traditional standalone computing has become increasingly time-consuming,which cannot meet the demands of scientific research and business.Therefore,this paper proposes the implementation of the parallel Clustering Large Application based upon RANdomized Search(CLARANS)clustering algorithm on the Spark cloud computing platformto cluster China’s climate regions usingmeteorological data from1988 to 2018.The aim is to address the challenge of applying clustering algorithms to large datasets.In this paper,the morphological similarity distance is adopted as the similarity measurement standard instead of Euclidean distance,which improves clustering accuracy.Furthermore,the issue of local optima caused by an improper selection of initial clustering centers is addressed by utilizing the max-distance criterion.Compared to the k-means clustering algorithm already implemented in the Spark platform,the proposed algorithm has strong robustness,can reduce the interference of outliers in the dataset on clustering results,and has higher parallel performance than the frequently used serial algorithms,thus improving the efficiency of big data analysis.This experiment compares the clustered centroid data with the annual average meteorological data of representative cities in the five typical meteorological regions that exist in China,and the results show that the clustering results are in good agreement with the meteorological data obtained from the National Meteorological Science Data Center.This algorithm has a positive effect on the clustering analysis of massive meteorological data and deserves attention in scientific research activities.

Adaptive coherence estimator based on the Krylov subspace technique for airborne radar

A novel adaptive detector for airborne radar space-time adaptive detection （STAD） in partially homogeneous environments is proposed. The novel detector combines the numerically stable Krylov subspace technique and diagonal loading technique, and it uses the framework of the adaptive coherence estimator （ACE）. It can effectively detect a target with low sample support. Compared with its natural competitors, the novel detector has higher proba- bility of detection （PD）, especially when the number of the training data is low. Moreover, it is shown to be practically constant false alarm rate （CFAR）.

Immunoregulatory polysaccharides from Apocynum venetum L.flowers stimulate phagocytosis and cytokine expression via activating the NF-κB/MAPK signaling pathways in RAW264.7 cells

Two immunomodulatory polysaccharides(Vp2a-Ⅱ and Vp3) were isolated and identified from Apocynum venetum L. flowers, and their innate immune-stimulating functions and working mechanisms were evaluated in RAW264.7 cells. Both the level of released nitric oxide(NO) and expression of inducible nitric oxide synthase(iNOS) m RNA were significantly enhanced in the RAW264.7 macrophages cells treated by Vp2a-Ⅱ and Vp3. Vp2a-Ⅱ(100–800 μg/m L) and Vp3(400 μg/mL) could significantly increase the phagocytic activity of RAW264.7 cells and the secretion and m RNA expression of TNF-α and IL-6 in a concentrationdependent manner through affecting mitogen-activated protein kinase(MAPK) activity and nuclear factor κB(NF-κB) nuclear translocation. Vp2a-Ⅱ might activate the MAPK signaling pathways and induce the nuclear translocation of NF-κB p65, whilst Vp3 likely activated the NF-κB and MAPK signaling pathways without influencing the p38 MAPK route.

A Fast Approach for Predicting Aerodynamic Noise Sources of High-Speed Train Running in Tunnel

The aerodynamic noise of high-speed trains passing through a tunnel has gradually become an important issue.Numerical approaches for predicting the aerodynamic noise sources of high-speed trains running in tunnels are the key to alleviating aerodynamic noise issues.In this paper,two typical numerical methods are used to calculate the aerodynamic noise of high-speed trains.These are the static method combined with non-reflective boundary conditions and the dynamic mesh method combined with adaptive mesh.The fluctuating pressure,flow field and aerodynamic noise source are numerically simulated using the abovemethods.The results showthat the fluctuating pressure,flow field structure and noise source characteristics obtained using different methods,are basically consistent.Compared to the dynamic mesh method,the pressure,vortex size and noise source radiation intensity,obtained by the static method,are larger.The differences are in the tail car and its wake.The two calculation methods show that the spectral characteristics of the surface noise source are consistent.The maximum difference in the sound pressure level is 1.9 dBA.The static method is more efficient and more suitable for engineering applications.

Natural products:Regulating glucose metabolism and improving insulin resistance

Compounds with regulating glucose metabolism and improving insulin resistance(IR)activity are abundant in nature and can be obtained from several sources.They have high potential to be used to treat diabetes mellitus.These compounds isolated from natural plants can be classified seven categories:terpenoids,alkaloids,quinones,flavonoids,phenols,phenyl propanoids,steroids,and other types of compounds.They exert biological effects by different ways and mechanisms.This review illustrated the potential natural products as a rich resource in regulation of glucose metabolism and IR,as well as their mechanisms.

Parameter optimization of control system design for uncertain wireless power transfer systems using modified genetic algorithm

The closed-loop wireless power transfer(WPT)system can realize constant voltage output in the presence of perturbation.However,the parameter design of the controller is a difficult problem.The traditional trial-and-error method is time-consuming and difficult to find optimal parameters.A parameter optimization strategy of control systems for uncertain WPT systems using the modified genetic algorithm(MGA)is proposed.Firstly,because the system has different characteristics at different periods,the simulation process is divided into three stages.The first one is the start-up stage,in which we mainly consider the overshoot and the rate of the voltage rise.The second one is the tracking stage,in which the tracking time and switching loss are mainly considered.The third one is the stabilisation stage,in which the steady-state error and switching loss are mainly considered.Secondly,three cost functions are designed according to the characteristics of the three stages,and then the optimal controller parameters of each stage are obtained by using MGA.Finally,the effectiveness of the proposed method is verified by simulation.The optimization results show that compared with the previous parameter optimization method,the optimal controller parameters obtained by the proposed method make the WPT system achieve better performance.

Variations in the natural 13C and 15N abundance of plants and soils under long-term N addition and precipitation reduction:interpretation of C and N dynamics

Background:The nitrogen isotope natural abundance(δ^(15)N)provides integrated information on ecosystem N dynamics,and carbon isotope natural abundance(δ^(13)C)has been used to infer how water-using processes of plants change in terrestrial ecosystems.However,howδ^(13)C andδ^(15)N abundances in plant life and soils respond to N addition and water availability change is still unclear.Thus,δ^(13)C andδ^(15)N abundances in plant life and soils were used to investigate the effects of long-time(10 years)N addition(+50 kg N·ha^(−1)·yr^(−1)and precipitation reduction(−30%of throughfall)in forest C and N cycling traits in a temperate forest in northern China.Results:We analyzed theδ^(13)C andδ^(15)N values of dominant plant foliage,litterfall,fungal sporophores,roots,and soils in the study.The results showed thatδ^(15)N values of foliage,litterfall,and surface soil layer’s(0–10 cm)total N were significantly increased by N addition,whileδ^(15)N values of fine roots and coarse roots were considerably decreased.Nitrogen addition also significantly increased theδ^(13)C value of fine roots and total N concentration of the surface soil layer compared with the control.The C concentration,δ^(13)C,andδ^(15)N values of foliage andδ^(15)N values of fine roots were significantly increased by precipitation reduction,while N concentration of foliage and litterfall significantly decreased.The combined effects of N addition and precipitation reduction significantly increased theδ^(13)C andδ^(15)N values of foliage as well as theδ^(15)N values of fine roots andδ^(13)C values of litterfall.Furthermore,foliarδ^(15)N values were significantly correlated with foliageδ^(13)C values,surface soilδ^(15)N values,surface soil C concentration,and N concentrations.Nitrogen concentrations andδ^(13)C values of foliage were significantly correlated withδ^(15)N values and N concentrations of fine roots.Conclusions:This indicates that plants increasingly take up the heavier 15N under N addition and the heavier 13C and 15N under precipitation reduction,suggesting that N addition and precipitation reduction may lead to more open forest ecosystem C and N cycling and affect plant nutrient acquisition strategies.

Can femoral head necrosis induced by steroid therapy in patients infected with coronaviruses be reversed?

Recently,we read with interest the findings of Zhang et al.1 of the long-term bone consequences in severe acute respiratory syndrome(SARS)patients.Their conclusion suggested that pulmonary damage and femoral head necrosis could be halted and reversed in SARS patients during the 15-year follow-up.These results have very important implications for the treatment and health utility evaluation of coronavirus disease 2019(COVID-19).However,they did not explore the reasons for the reversal of femoral head necrosis after large doses of steroid pulse therapy,which may affect our understanding with regard to the treatment of COVID-19 patients.

Study on Chronic Diseases Comprehensive Intervention in Baoji of Shaanxi Province in China

Background: There is very limited data available about the epidemiology trial on chronic diseases comprehensive intervention. The aim of this study was to assess the effect of comprehensive intervention on chronic diseases in Baoji and provide basis for the improvement of chronic diseases intervention measures. Methods: Using four stages stratified random sampling method, comprehensive intervention measures were implemented on intervention group (575 individuals) respectively aimed at three crowds of whole population, high risk population and chronic diseases patients. The control group (782 individuals) did not receive special treatment. Two groups were evaluated effect after one year observation. Results: The chronic diseases prevalence rate of whole population in intervention group was lower than that in control group (P < 0.05), the blood pressure level and smoking proportion of high risk population in intervention group were lower than in control group (P < 0.05), and the blood pressure, blood glucose control rate of chronic diseases patients in intervention group were higher than in control group (P < 0.05). Conclusion: Comprehensive intervention could prevent the rise of chronic diseases prevalence. The intervention is effective in reducing or halting risk factors of high risk population, particularly in controlling blood pressure, blood glucose of patients. We should establish government leading, department cooperation, social participation, longtime and classified comprehensive intervention mechanism of chronic diseases. We believe that whole population should control the risk factors, high risk population should early diagnosis and treatment, chronic diseases patients should normalized management, and it could be applied in other counties.

Single-atom alloys prepared by two-step thermal evaporation

Single-atom alloys(SAAs)have gained significant attention due to their remarkable atomic utilization efficiency,interactions between single atoms(SAs)and metal supports,and free-atom-like electronic structure of dopant elements.In this work,we observed the formation of SAs in pre-deposited metal particles by a two-step thermal evaporation technique,thereby establishing the first instance of discovering SAAs by thermal evaporation.The discovery of SAAs by thermal evaporation extends the range of SAAs preparation methods to include this traditional synthetic technique,which offers convenience,cost-efficiency,and universality.The formation mechanism of SAAs prepared using this technique was elucidated by density functional theory calculations.It was demonstrated that thermal evaporation can be utilized to prepare SAAs with multiple SAs,further highlighting its universal applicability.

Dual-photoconductivity in monolayer PtSe_(2) ribbons

Two-dimensional platinum diselenide (PtSe_(2)) has been explored for applications in visible and infrared photodetectors, owing to its tunable electrical and optoelectronic properties governed by layer-dependent bandgaps. Studies have explored both positive photoconductivity (PPC) and negative photoconductivity (NPC) behaviors in few-layer PtSe_(2) thin films, proposing mechanisms related to gas molecule adsorption. However, these proposed mechanisms, typically based on models with ideal limit structures, often lacked consistency with the structure and scale of polycrystalline thin films employed in actual experiments. Here, photodetectors utilizing monolayer PtSe_(2) ribbons were designed, demonstrating a significant NPC effect upon exposure to visible light in atmospheric conditions, with device resistance increasing to over threefold the initial state. Under vacuum conditions, the device demonstrated PPC characteristics. Density functional theory calculations indicated that oxygen molecules physically adsorbed at the edges of PtSe_(2) ribbons were integral. Laser irradiation prompted the detachment of oxygen molecules from the ribbon’s edges, leading to a decreased carrier concentration in channel conductivity. The abundant edge sites of the ribbons endowed the photodetectors with a pronounced NPC response. This study diverted from traditional multilayer PtSe_(2) films to explore monolayer PtSe_(2) ribbons. These ribbons, as limit structures, offered a more fundamental insight into the intrinsic photoconductivity properties of PtSe_(2). Photodetectors employing PtSe_(2) ribbons presented novel application prospects in low-power photodetection, gas detection, and additional fields.

Millimeter waves in medical applications:status and prospects

Millimeter waves are electromagnetic waves with wavelengths of 1–10 mm,which have characteristics of high frequency and short wavelength.They have gradually and widely been used in engineering and medical fields.We have identified studies related to millimeter waves in the biomedical field and summarized the biological effects of millimeter waves and their current status in medical applications.Finally,the shortcomings of existing studies and future developments were analyzed and discussed,with the aim of providing a reference for further research and development of millimeter waves in the medical field.

糖尿病足智能化管理平台建设需求的质性研究

目的探讨医护人员及糖尿病高危足患者对糖尿病足智能化管理平台建设的需求。方法采用方便抽样的方法,抽取中南大学湘雅医院糖尿病足防治联盟医院内的医护人员为医护人员部分的研究对象,抽取2022年1月至2023年6月在中南大学湘雅医院内分泌科就诊的糖尿病高危足患者为患者部分的研究对象。对纳入医护人员及糖尿病高危足患者进行半结构式访谈,使用Nvivo 12软件及Colaizzi分析研究对象对糖尿病足智能化管理平台建设的需求。结果共纳入7名医师、8名护士及10例糖尿病高危足患者。半结构式访谈结果显示,医护人员对糖尿病足智能化管理平台建设的需求主要体现在"患者信息管理、交流与会诊、学术与统计、健康教育、临床决策"5个方面,患者的需求主要体现在"健康教育相关知识、获取资讯的需求、多种信息传输形式并存"3个方面。结论医护人员与患者对于糖尿病足智能化管理平台建设的需求存在差异,医护人员对平台功能多样化与设计便捷性的需求较大,而患者则更关心健康教育、最新资讯获取及多种信息传输形式并存。

Symbiotic mycorrhizal types affect patterns of tree aboveground and belowground C allocation in Northeast China

Background Given the ubiquitous nature of mycorrhizal symbioses,different symbiotic fungi have obvious differences in structure and function,which may affect associated tree aboveground and belowground C allocation dynamics.However,the mechanisms underlying tree aboveground and belowground C allocation and its response to symbiotic mycorrhizal types and other factors(e.g.,resource availability)remain poorly understood.Results We used forest inventory data to explore the potential mechanism of tree aboveground and belowground C allocation patterns in Northeast China.Our results showed that tree-fungal symbioses were related to the patterns of tree C allocation.The ratio of aboveground to belowground C pool was significantly higher in ectomycorrhizal(EM)-associated trees than that in arbuscular mycorrhizal(AM)-associated trees.Symbiotic mycorrhizal types were associ-ated with the responses of tree aboveground and belowground C allocation to different factors,such as mean annual precipitation(MAP)and mean annual temperature(MAT).Almost all factors significantly increased aboveground C allocation in AM-associated trees but significantly decreased it in EM-associated trees.Moreover,after controlling the other factors,the effects of climate factors(MAT and MAP)on the C allocation of AM-and EM-associated trees were similar.Increases in MAT and MAP significantly increased belowground and aboveground C allocation,respectively.Conclusions Our results demonstrate symbiotic mycorrhizal types play an important role in controlling tree aboveground and belowground C allocation and dynamics.

糖尿病患者功能失调性态度与焦虑抑郁的关系分析

目的:探讨糖尿病患者功能失调性态度与焦虑、抑郁状况,并分析功能失调性态度与焦虑、抑郁的关系.方法:于2022年4月8-23日对湖南省15家医院的糖尿病住院患者,使用功能失调态度量表(DAS)、广泛性焦虑自评量表(GAD-7)和患者健康问卷抑郁症状群量表(PHQ-9),通过"问卷星"进行线上问卷调查;采用Pearson相关分析了解功能失调性态度与焦虑和抑郁相关性.结果:534例糖尿病患者中43.8%有抑郁情绪,34.1%存在焦虑问题;糖尿病患者的DAS总分为(130.20±30.83)分;DAS与GAD-7(r=0.498,P<0.01)、PHQ-9(r=0.516,P<0.01)评分均呈正相关.结论:糖尿病患者功能失调性态度处于低水平,功能失调性态度与焦虑、抑郁呈正相关;临床医务人员应对肥胖、情绪不良的糖尿病患者进行评估,并有针对性的对其加强健康教育及相关心理干预,以尽可能改善患者功能失调性态度水平及不良情绪,提高患者的生活质量.

催化中的极限结构:单原子,亚纳米团簇和电子

催化剂的尺寸在降低到原子尺度时表现出显著的性能提升,如原子利用率提高、配位不饱和度增强和比表面积增加.为了实现高效催化,针对原子分布和电子行为的精细设计与调控至关重要,由此引入了“极限结构”这一概念.极限结构涵盖了单个原子、双原子,单个原子链/层和亚纳米团簇等结构.围绕这些极限结构在原子和电子尺度上研究催化剂,可以更深入地理解其本征性质并为未来的催化剂设计提供新的方向.本文总结了极限结构在催化应用中的最新进展和研究方向,重点讨论单原子、亚纳米团簇和电子尺度的反应动力学.特别关注极限结构的优化策略,如金属-支撑作用增强、缺陷和电子结构调控.探讨了各种极限结构之间的相互关系,强调了每个结构的特性.最后,展望了极限结构在催化领域的未来发展趋势.

Pollen self-elimination CRISPR–Cas genome editing prevents transgenic pollen dispersal in maize

Dear Editor,Genome editing with clustered regularly interspaced short palindromic repeats(CRISPR)–CRISPR-associated nuclease(Cas)-mediated technologies have revolutionized basic plant science and crop genetic improvement(Chen et al.,2019).Stable genetic transformation of CRISPR–Cas cassette(s)is the main approach to genome editing in planta.In many sexually reproducing plants,a major concern is the dispersal of genetically modified elements through pollen(Devos et al.,2005).Maize(Zea mays L.).

禾本科三倍体:形成、鉴定与利用

禾本科三倍体的形成途径包括2n配子融合、倍性间杂交、多精受精和胚乳培养。其中,2n配子融合和倍性间杂交分别为自然界和人工合成三倍体的主要途径。该文介绍了形态学观测、染色体分析、流式细胞术和分子标记等倍性鉴定方法在禾本科三倍体中的应用及其优缺点。目前,三倍体在禾谷类作物中无直接应用价值,但可作为通往多倍体、非整倍体和转移异源基因的遗传桥梁。多年生禾本科三倍体(特别是异源三倍体)在饲草或能源作物中已得到广泛应用,在该类型禾本科作物中均可直接尝试三倍体育种。多倍体的三倍体育种和无融合生殖三倍体育种可作为未来禾本科三倍体的研究方向。三倍性胚乳培养可以一步合成三倍体,多精受精可以实现遗传上3个不同基因组的一步融合,在三倍体研究中应予以重视。鉴于2n配子融合、多精受精的稀有特性和倍性间杂交、胚乳培养频繁的染色体变异,高通量三倍体鉴定技术的发展将是三倍体研究实现突破的关键。

Human umbilical cord mesenchymal stem cells for psoriasis:a phase 1/2a,single-arm study

Psoriasis is a common,chronic immune-mediated systemic disease that had no effective and durable treatment.Mesenchymal stem cells(MSCs)have immunomodulatory properties.Therefore,we performed a phase 1/2a,single-arm clinical trial to evaluate the safety and efficacy of human umbilical cord-derived MSCs(UMSCs)in the treatment of psoriasis and to preliminarily explore the possible mechanisms.Seventeen patients with psoriasis were enrolled and received UMsC infusions.Adverse events,laboratory parameters,PASl,and PGA were analyzed.We did not observe obvious side effects during the treatment and 6-month follow-up.A total of 47.1%(8/17)of the psoriasis patients had at least 40%improvement in the PASl score,and 17.6%(3/17)had no sign of disease or minimal disease based on the PGA score.And the efficiency was 25%(2/8)for males and 66.7%(6/9)for females.After UMSC transplantation(UMSCT),the frequencies of Tregs and CD4^(+)memory T cells were significantly increased,and the frequencies of T helper(Th)17 and CD4^(+)naive T cells were significantly decreased in peripheral blood(PB)of psoriasis patients.And all responders showed significant increases in Tregs and CD4^(+)memory T cells,and significant decreases in Th17 cells and serum IL-17 level after UMsCT.And baseline level of Tregs in responders were significantly lower than those in nonresponders.In conclusion,allogeneic UMSCT is safe and partially effective in psoriasis patients,and level of Tregs may be used as a potent biomarker to predict the clinical efficacy of UMSCT.Trial registration Clinical Trials NCT03765957.