In this article,we looked at metallenes,a novel class of two-dimensional(2D)metals that are attracting interest in the energy and catalysis sectors.Catalysis is one area where their exceptional physicochemical and ele...In this article,we looked at metallenes,a novel class of two-dimensional(2D)metals that are attracting interest in the energy and catalysis sectors.Catalysis is one area where their exceptional physicochemical and electrical characteristics might be useful.Metallenes are unique because they include several metal atoms that are not in a coordinated bond.This makes them more active and improves their atomic uti-lization,which in turn increases their catalytic potential.This article delves into the potential of two-dimensional metals as electrocatalysts for carbon dioxide reduction,fuel oxidation,oxygen evolution,and oxygen reduction reactions in the context of sustainable energy conversion.Owing to the exception-ally high surface-to-volume ratio,large surface area as well as their optimized atomic use efficiency,2D materials defined by atomic layers are crucial for surface-related sustainable energy applications.Due to its exceptional properties,such as high conductivity and the ability to enhance the exposure of active metal sites,2D metallenes have recently attracted a lot of interest for use in catalysis,electronics,and energy-related applications.With their highly mobility,adjustable surface states,and electrical struc-tures that can be fine-tuned,2D metallenes are promising nanostructure materials for use in energy con-version with the sustainable applications.展开更多
Ridge-furrow film mulching has been proven to be an effective water-saving and yield-improving planting pattern in arid and semi-arid regions.Drought is the main factor limiting the local agricultural production in th...Ridge-furrow film mulching has been proven to be an effective water-saving and yield-improving planting pattern in arid and semi-arid regions.Drought is the main factor limiting the local agricultural production in the Loess Plateau of China.In this study,we tried to select a suitable ridge-furrow mulching system to improve this situation.A two-year field experiment of summer maize(Zea mays L.)during the growing seasons of 2017 and 2018 was conducted to systematically analyze the effects of flat planting with no film mulching(CK),ridge-furrow with ridges mulching and furrows bare(RFM),and double ridges and furrows full mulching(DRFFM)on soil temperature,soil water storage(SWS),root growth,aboveground dry matter,water use efficiency(WUE),and grain yield.Both RFM and DRFFM significantly increased soil temperature in ridges,while soil temperature in furrows for RFM and DRFFM was similar to that for CK.The largest SWS was observed in DRFFM,followed by RFM and CK,with significant differences among them.SWS was lower in ridges than in furrows for RFM.DRFFM treatment kept soil water in ridges,resulting in higher SWS in ridges than in furrows after a period of no water input.Across the two growing seasons,compared with CK,RFM increased root mass by 10.2%and 19.3%at the jointing and filling stages,respectively,and DRFFM increased root mass by 7.9%at the jointing stage but decreased root mass by 6.0%at the filling stage.Over the two growing seasons,root length at the jointing and filling stages was respectively increased by 75.4%and 58.7%in DRFFM,and 20.6%and 30.2%in RFM.Relative to the jointing stage,the increased proportions of root mass and length at the filling stage were respectively 42.8%and 94.9%in DRFFM,63.2%and 115.1%in CK,and 76.7%and 132.1%in RFM,over the two growing seasons,showing that DRFFM slowed down root growth while RFM promoted root growth at the later growth stages.DRFFM treatment increased root mass and root length in ridges and decreased them in 0-30 cm soil layer,while RFM increased them in 0-30 cm soil layer.Compared with CK,DRFFM decreased aboveground dry matter while RFM increased it.Evapotranspiration was reduced by 9.8%and 7.1%in DRFFM and RFM,respectively,across the two growing seasons.Grain yield was decreased by 14.3%in DRFFM and increased by 13.6%in RFM compared with CK over the two growing seasons.WUE in CK was non-significantly 6.8%higher than that in DRFFM and significantly 22.5%lower than that in RFM across the two growing seasons.Thus,RFM planting pattern is recommended as a viable water-saving option for summer maize in the Loess Plateau of China.展开更多
The Middle East Respiratory Syndrome (MERS-CoV) is a potentially fatal respiratory viral infection that has had outbreaks in the Middle East and Asia region starting in 2012. As recent as 2015, MERS had outbreaks in S...The Middle East Respiratory Syndrome (MERS-CoV) is a potentially fatal respiratory viral infection that has had outbreaks in the Middle East and Asia region starting in 2012. As recent as 2015, MERS had outbreaks in South Korea, resulting in 36 deaths among 186 infected patients. The purpose of this thesis is to gain an in-depth understanding of how this viral infection behaves in outbreaks and how it is spread around the globe. To gain insight, real time analysis was performed under a case study methodology based on pooled data from the Ministry of Health & Welfare of South Korea. We calculated a striated mortality rate based on gender, age, and the presence of pre-existing health conditions ranging from heart, lung, and kidney diseases. We found that MERS outbreak follows the pattern of a point source outbreak, largely spurred by the patient-referral system under the universal healthcare system in South Korea. The purpose of this case is to discuss the benefits and challenges of such patient referral system, and to offer a possible solution in improving transparency between healthcare providers and the government under a universal healthcare system to prevent future outbreaks.展开更多
BACKGROUND Integrating conventional ultrasound features with 2D shear wave elastography(2D-SWE)can potentially enhance preoperative hepatocellular carcinoma(HCC)predictions.AIM To develop a 2D-SWE-based predictive mod...BACKGROUND Integrating conventional ultrasound features with 2D shear wave elastography(2D-SWE)can potentially enhance preoperative hepatocellular carcinoma(HCC)predictions.AIM To develop a 2D-SWE-based predictive model for preoperative identification of HCC.METHODS A retrospective analysis of 884 patients who underwent liver resection and pathology evaluation from February 2021 to August 2023 was conducted at the Oriental Hepatobiliary Surgery Hospital.The patients were divided into the modeling group(n=720)and the control group(n=164).The study included conventional ultrasound,2D-SWE,and preoperative laboratory tests.Multiple logistic regression was used to identify independent predictive factors for RESULTS In the modeling group analysis,maximal elasticity(Emax)of tumors and their peripheries,platelet count,cirrhosis,and blood flow were independent risk indicators for malignancies.These factors yielded an area under the curve of 0.77(95%confidence interval:0.73-0.81)with 84%sensitivity and 61%specificity.The model demonstrated good calibration in both the construction and validation cohorts,as shown by the calibration graph and Hosmer-Lemeshow test(P=0.683 and P=0.658,respectively).Additionally,the mean elasticity(Emean)of the tumor periphery was identified as a risk factor for microvascular invasion(MVI)in malignant liver tumors(P=0.003).Patients receiving antiviral treatment differed significantly in platelet count(P=0.002),Emax of tumors(P=0.033),Emean of tumors(P=0.042),Emax at tumor periphery(P<0.001),and Emean at tumor periphery(P=0.003).CONCLUSION 2D-SWE’s hardness value serves as a valuable marker for enhancing the preoperative diagnosis of malignant liver lesions,correlating significantly with MVI and antiviral treatment efficacy.展开更多
Locusts are agricultural pests around the world. To cognize how locust distribution density and community structure are related to the hydrothermal and vegetation growth conditions of their habitats and thereby provid...Locusts are agricultural pests around the world. To cognize how locust distribution density and community structure are related to the hydrothermal and vegetation growth conditions of their habitats and thereby providing rapid and accurate warning of locust invasions, it is important to develop efficient and accurate techniques for acquiring locust information. In this paper, by analyzing the differences between the morphological features of Locusta migratoria manilensis and Oedaleus decorus asiaticus, we proposed a semi-automatic locust species and instar information detection model based on locust image segmentation, locust feature variable extraction and support vector machine(SVM) classification. And we subsequently examined its applicability and accuracy based on sample image data acquired in the field. Locust image segmentation experiment showed that the proposed GrabCut-based interactive segmentation method can be used to rapidly extract images of various locust body parts and exhibits excellent operability. In a locust feature variable extraction experiment, the textural, color and morphological features of various locust body parts were calculated. Based on the results, eight feature variables were selected to identify locust species and instars using outlier detection, variable function calculation and principal component analysis. An SVM-based locust classification experiment achieved a semi-automatic detection accuracy of 96.16% when a polynomial kernel function with a penalty factor parameter c of 2 040 and a gamma parameter g of 0.5 was used. The proposed detection model exhibits advantages such as high applicability and accuracy when it is used to identify locust instars of L. migratoria manilensis and O. decorus asiaticus, and it can also be used to identify other species of locusts.展开更多
To better understand the interaction of N transformation and exogenous C source and manage N fertilization, the effects of glucose addition on N transformation were determined in paddy soils with a gradient of soil or...To better understand the interaction of N transformation and exogenous C source and manage N fertilization, the effects of glucose addition on N transformation were determined in paddy soils with a gradient of soil organic C content. Changes in N mineralization, nitrification and denitrification, as well as their response to glucose addition were measured by incubation experiments in paddy soils derived from Quaternary red clay in subtropical China. Mineralization and denitrification were changed in order of increasing soil fertilities： high 〉 middle 〉 low. During the first week of incubation, net N mineralization and denitrification rates in paddy soil with high fertility were 1.9 and 1.1 times of those in soil with middle fertility and 5.3 and 2.9 times of those in soil with low fertility, respectively. Addition of glucose decreased net N mineralization by approximately 78.8, 109.2 and 177.4% in soils with high, middle and low fertility, respectively. However, denitrification rates in soils with middle and low fertility were increased by 14.4 and 166.2% respectively. The highest nitrate content among the paddy soils tested was 0.62 mg kg-1 and the highest nitrification ratio was 0.33%. Addition of glucose had no obvious effects on nitrate content and nitrification ratio. It was suggested that the intensity of mineralization and denitrification was quite different in soils with different fertility, and increased with increasing soil organic C content. Addition of glucose decreased mineralization, but increased denitrification, and the shifts were greater in soil with low than in soil with high organic C content. Neither addition of glucose nor inherent soil organic C had obvious effects on nitrification in paddy soils tested.展开更多
In the framework of the gravity＇s rainbow, the asymptotic quasinormal modes of the modified Schwarzschild black holes undergoing a scalar perturbation are investigated. By using the monodromy method, we analytically ...In the framework of the gravity＇s rainbow, the asymptotic quasinormal modes of the modified Schwarzschild black holes undergoing a scalar perturbation are investigated. By using the monodromy method, we analytically calculated the asymptotic quasinormal frequencies, which depend on not only the mass parameter of the black hole, but also the particle＇s energy of the perturbation field. Meanwhile, the real parts of the asymptotic quasinormal modes can be expressed as TH In 3, which is consistent with Hod＇s conjecture. In addition, for the quantum corrected black hole, the area spacing is independent of the particle＇s energy, even though the area itself depends on the particle＇s energy. And that, by relating the area spectrum to loop quantum gravity, the Barbero-Immirzi parameter is given and it remains the same as from the usual black hole.展开更多
Polyimide is a typical complex high-molecular polymer of imide monomers,which is widely used in the manufacture of parts for aerospace engineering.The hypervelocity impacts between the spacecraft and orbital debris ca...Polyimide is a typical complex high-molecular polymer of imide monomers,which is widely used in the manufacture of parts for aerospace engineering.The hypervelocity impacts between the spacecraft and orbital debris can induce great damage to the spacecraft.In order to improve the safety of spacecraft,the characteristics of polyimide debris clouds produced by hypervelocity impact should be studied.Firstly,a Mie-Grüneisen equation of state based on the shock adiabat for polyimide,which describes the mechanical behavior in the numerical simulation,was obtained from hypervelocity impact experiments,then a 3-dimentional smoothed particle hydrodynamics program was compiled to numerically simulate the hypervelocity impact between aluminum projectiles(orbital debris)and polyimide targets with different impact velocities(3.km/s,5.km/s,8.km/s)and angles(0°,30°,45°,60°),finally typical shapes of debris clouds produced in different impact velocities and angles were collected from simulation results,the characteristics of which were systemically discussed.展开更多
The study investigated the university students＇ attitudes towards the coexistence of the standard discourse and the emergent discourses through a questionnaire. 223 sophomores in Xinjiang Normal University participat...The study investigated the university students＇ attitudes towards the coexistence of the standard discourse and the emergent discourses through a questionnaire. 223 sophomores in Xinjiang Normal University participated in the survey. The results show that these students tend to accept the emergent discourses in terms of their new vocabulary words, such as ＂yumi＂. Although the standard discourse dominates the students＇ life, the emergent discourses are accepted and used by these students. With regard to the view to purify the Chinese language, human concern and tolerance for the coexistence of various discourses are suggested.展开更多
This study applies ArcGIS to analyze the spatiotemporal distribution of cultural sites in the Ill River Valley in northwestern China. It explores relationships between the sites＇ spatiotemporal evolutionary character...This study applies ArcGIS to analyze the spatiotemporal distribution of cultural sites in the Ill River Valley in northwestern China. It explores relationships between the sites＇ spatiotemporal evolutionary characteristics, human history, and the natural environment. The results indicate that the numbers and proportions of the sites, and the frequency of their oc- currence, exhibited an inverted V-shaped change trend during six historical periods. The ＂high in the east and low in the west＂ spatial distribution pattern of the first three periods shifted to the one the ＂high in the west and low in the east＂ during the latter three periods, demonstrating a change in the spatial center of gravity of human activities. The sites were mainly distributed on slopes of grades 1-5, with their proportions increasing from 75% during the Spring and Autumn Period （770 BC-476 BC）-Qin Dynasty （221 BC-207 BC） to 93.75% during the Qing Dynasty-Modern period. The concentrated distribution of site elevations shifted from grades 4-8 during the Spring and Autumn Period-Qin Dynasty, and the Western Han （206 BC-8）-Southern and Northern Dynasties （420-589）, to grades 1-4 during the latter three periods. The number of sites showed a shifting trend from high-elevation mountains and hills to low-elevation plains, and from high slopes to low slopes. In particular, the sites exhibited a special ＂moist＂ evolutionary pattern of migration from middle and upstream areas to downstream areas, as opposed to the migration pattern of sites located in typical arid areas. The study also considered factors influencing the distribution and spatiotemporal evolution of cultural sites, notably, human factors and natural factors.展开更多
The modified version of Yahalom protocol improved by Burrows, Abradi, and Needham （BAN） still has security drawbacks. This study analyzed such flaws in a detailed way from the point of strand spaces, which is a nove...The modified version of Yahalom protocol improved by Burrows, Abradi, and Needham （BAN） still has security drawbacks. This study analyzed such flaws in a detailed way from the point of strand spaces, which is a novel method of analyzing protoeol＇s security. First, a mathematical model of BAN-Yahalom protocol is constructed. Second, penetrators＇ abilities are restricted with a rigorous and formalized definition. Moreover, to increase the security of this protocol against potential attackers in practice, a further improvement is made to the protocol. Future application of this re-improved protocol is also discussed.展开更多
Social vulnerability in this study represents the differences between the capacity to cope with natural hazards and disaster losses suffered within and between places.The assessment of social vulnerability has been re...Social vulnerability in this study represents the differences between the capacity to cope with natural hazards and disaster losses suffered within and between places.The assessment of social vulnerability has been recognized as a critical step in understanding natural hazard risks and enhancing effective response capabilities.This article presents an initial study of the social vulnerability of the Beijing-Tianjin-Hebei(B-T-H) Region in China.The goal is to replicate and test the applicability of the United States Social Vulnerability Index(So VI) method in a Chinese cultural context.Thirty-nine variables adapted from the So VI were collected in relation to two aspects:socioeconomic vulnerability and built environment vulnerability.Using factor analysis,seven factors were extracted from the variable set:the structure of social development,the level of economic and government financial strength,social justice and poverty,family structure,the intensity of space development,the status of residential housing and transportation,and building structure.Factor scores were summed to get the final So VI scores and the most and least vulnerable units were identified and mapped.The highest social vulnerability is concentrated in the northwest of the study area.The least socially vulnerable areas are mainly distributed in the Beijing,Tianjin and Shijiazhuang core urban peripheral and central city areas of the prefecture-level cities.The results show that this method is a useful tool for revealing places that have a high level of vulnerability,in other words,areas which are more likely to face significant challenges in coping with a large-scale event.These findings could provide a scientific basis for policy making and the implementation of disaster prevention and mitigation in China.展开更多
Simultaneous and quantitative detection of multiple exosomal micro RNAs(miRNAs)was successfully performed by a surface-enhanced Raman scattering(SERS)assay consisting of Raman probes and capture probes.In this design,...Simultaneous and quantitative detection of multiple exosomal micro RNAs(miRNAs)was successfully performed by a surface-enhanced Raman scattering(SERS)assay consisting of Raman probes and capture probes.In this design,the asymmetric core-shell structured Au@Au@Ag nanoparticles were first synthesized by layer-by-layer self-assembly method and modified with different Raman molecules and recognition sequences(poly A-DNA)to prepare the surface-enhanced Raman probes.Then,the streptavidinmodified magnetic beads were used to immobilize the biotinylated DNA capture sequences(biotin-DNA)to obtain capture probes.In the presence of target exosomal miRNAs,the Raman probes and capture probes could bind to the target exosomal miRNAs in the partial hybridization manner.Thus,the developed SERS sensor could indicate the target miRNAs levels in the buffer solution.Using breast cancerrelated miRNAs as model targets,the limits of detection of this sensor were determined to be 1.076 fmol/L for synthetic miR-21,0.068 fmol/L for synthetic miR-126,and 4.57 fmol/L for synthetic miR-1246,respectively.Such SERS sensors were further employed to detect the miR-21 in 20%human serum and the extraction solution of exosomes,respectively.Therefore,simultaneous and multiplex detection of cancerrelated exosomal miRNAs by this assay could provide new opportunities for further biomedical applications.展开更多
It is noted that in the new Particle Data Group(PDG) version the rare decays of the Λ_(b) baryon have been revised with more accuracy. The new results show that most of the existing theoretical results on the process...It is noted that in the new Particle Data Group(PDG) version the rare decays of the Λ_(b) baryon have been revised with more accuracy. The new results show that most of the existing theoretical results on the process Λ_(b)→Λ_(γ) Lgbare larger than those of experiments. With the improved higher-order light-cone distribution amplitudes of the Λ baryon, we reanalyze the process in the framework of light-cone quantum chromodynamics sum rules and the branching ratio is estimated to be Br (Λ_(b)→Λ_(γ))=(7.38-0.39+0.40)×10^(16), which is consistent with the new experimental result. Furthermore, another process Λ_(b)→Λl+l- is also analyzed in the same frame. The final branching ratio is calculated to be Br (Λ_(b)→Λl+l-)=1.20×10^(-6), which is in good accordance with the data from the PDG and other theoretical predictions.展开更多
Objective:To focus on the isolation and preliminary characterization of marine sponges associated Actinobacteria particularly Streptomyces species and also their antagonistic activities against bacterial and fungal pa...Objective:To focus on the isolation and preliminary characterization of marine sponges associated Actinobacteria particularly Streptomyces species and also their antagonistic activities against bacterial and fungal pathogens.Methods:The sponges were collected from Kovalam and Vizhinjam port of south-west coast of Kerala,India.Isolation of strains was carried out from sponge extracts using international Streptomyces project media.For preliminary identification of the strains,morphological(mycelial colouration,soluble pigments,melanoid pigmentation,spore morphology),nutritional uptake(carbon utilisation,amonoacids influence,sodium chloride tolerance),physiological(pH,temperature)and chemotaxonomical characterization were done.Antimicrobial studies were also carried out for the selected strains.Results:With the help of the spicule structures,the collected marine sponges were identified as Callyspongia diffusa,Mycale mytilorum,Tedania anhelans and Dysidea fragilis.Nearly 94 strains were primarily isolated from these sponges and further they were sub-cultured using international Streptomyces project media.The strains exhibited different mycelial colouration(aerial and substrate),soluble and melanoid pigmentations.The strains possessed three types of sporophore morphology namely rectus flexibilis,spiral and retinaculiaperti.Among the 94 isolates,seven exhibited antibacterial and antifungal activities with maximal zone of inhibition of 30 mm.The nutritional,physiological and chemotaxonomical characteristic study helped in the conventional identification of the seven strains and they all suggest that the strains to be grouped under the genus Streptomyces.Conclusions:The present study clearly helps in the preliminary identification of the isolates associated with marine sponges.Antagonistic activities prove the production of antimicrobial metabolites against the pathogens.Marine sponges associated Streptomyces are universally well known for their synthesis of many bioactive compounds such as antibiotics,enzymes,enzyme inhibitors and food grade pigments.They also have certain biotechnological applications like probiotics and single cell proteins.These marine Streptomyces bioactive metabolites can be the futuristic solution for the dreadful diseases.展开更多
基金funded by the Princess Nourah bint Abdulrahman University Researchers Supporting Project number(PNURSP2024R24),Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabiafunding from the Prince Sattam bin Abdulaziz University project number(PSAU/2023/R/1444).
文摘In this article,we looked at metallenes,a novel class of two-dimensional(2D)metals that are attracting interest in the energy and catalysis sectors.Catalysis is one area where their exceptional physicochemical and electrical characteristics might be useful.Metallenes are unique because they include several metal atoms that are not in a coordinated bond.This makes them more active and improves their atomic uti-lization,which in turn increases their catalytic potential.This article delves into the potential of two-dimensional metals as electrocatalysts for carbon dioxide reduction,fuel oxidation,oxygen evolution,and oxygen reduction reactions in the context of sustainable energy conversion.Owing to the exception-ally high surface-to-volume ratio,large surface area as well as their optimized atomic use efficiency,2D materials defined by atomic layers are crucial for surface-related sustainable energy applications.Due to its exceptional properties,such as high conductivity and the ability to enhance the exposure of active metal sites,2D metallenes have recently attracted a lot of interest for use in catalysis,electronics,and energy-related applications.With their highly mobility,adjustable surface states,and electrical struc-tures that can be fine-tuned,2D metallenes are promising nanostructure materials for use in energy con-version with the sustainable applications.
基金This study was funded by the National Natural Science Foundation of China(51979235,51909221)the Agricultural Science and Technology Innovation Integration Promotion Project of Shaanxi Province,China(SXNYLSYF2019-01)+1 种基金the China Postdoctoral Science Foundation(2019M650277)the Natural Science Basic Research Plan in Shaanxi Province,China(2020JQ-276).
文摘Ridge-furrow film mulching has been proven to be an effective water-saving and yield-improving planting pattern in arid and semi-arid regions.Drought is the main factor limiting the local agricultural production in the Loess Plateau of China.In this study,we tried to select a suitable ridge-furrow mulching system to improve this situation.A two-year field experiment of summer maize(Zea mays L.)during the growing seasons of 2017 and 2018 was conducted to systematically analyze the effects of flat planting with no film mulching(CK),ridge-furrow with ridges mulching and furrows bare(RFM),and double ridges and furrows full mulching(DRFFM)on soil temperature,soil water storage(SWS),root growth,aboveground dry matter,water use efficiency(WUE),and grain yield.Both RFM and DRFFM significantly increased soil temperature in ridges,while soil temperature in furrows for RFM and DRFFM was similar to that for CK.The largest SWS was observed in DRFFM,followed by RFM and CK,with significant differences among them.SWS was lower in ridges than in furrows for RFM.DRFFM treatment kept soil water in ridges,resulting in higher SWS in ridges than in furrows after a period of no water input.Across the two growing seasons,compared with CK,RFM increased root mass by 10.2%and 19.3%at the jointing and filling stages,respectively,and DRFFM increased root mass by 7.9%at the jointing stage but decreased root mass by 6.0%at the filling stage.Over the two growing seasons,root length at the jointing and filling stages was respectively increased by 75.4%and 58.7%in DRFFM,and 20.6%and 30.2%in RFM.Relative to the jointing stage,the increased proportions of root mass and length at the filling stage were respectively 42.8%and 94.9%in DRFFM,63.2%and 115.1%in CK,and 76.7%and 132.1%in RFM,over the two growing seasons,showing that DRFFM slowed down root growth while RFM promoted root growth at the later growth stages.DRFFM treatment increased root mass and root length in ridges and decreased them in 0-30 cm soil layer,while RFM increased them in 0-30 cm soil layer.Compared with CK,DRFFM decreased aboveground dry matter while RFM increased it.Evapotranspiration was reduced by 9.8%and 7.1%in DRFFM and RFM,respectively,across the two growing seasons.Grain yield was decreased by 14.3%in DRFFM and increased by 13.6%in RFM compared with CK over the two growing seasons.WUE in CK was non-significantly 6.8%higher than that in DRFFM and significantly 22.5%lower than that in RFM across the two growing seasons.Thus,RFM planting pattern is recommended as a viable water-saving option for summer maize in the Loess Plateau of China.
文摘The Middle East Respiratory Syndrome (MERS-CoV) is a potentially fatal respiratory viral infection that has had outbreaks in the Middle East and Asia region starting in 2012. As recent as 2015, MERS had outbreaks in South Korea, resulting in 36 deaths among 186 infected patients. The purpose of this thesis is to gain an in-depth understanding of how this viral infection behaves in outbreaks and how it is spread around the globe. To gain insight, real time analysis was performed under a case study methodology based on pooled data from the Ministry of Health & Welfare of South Korea. We calculated a striated mortality rate based on gender, age, and the presence of pre-existing health conditions ranging from heart, lung, and kidney diseases. We found that MERS outbreak follows the pattern of a point source outbreak, largely spurred by the patient-referral system under the universal healthcare system in South Korea. The purpose of this case is to discuss the benefits and challenges of such patient referral system, and to offer a possible solution in improving transparency between healthcare providers and the government under a universal healthcare system to prevent future outbreaks.
基金Supported by the National Natural Science Foundation of China Youth Training Project,No.2021GZR003and Medical-engineering Interdisciplinary Research Youth Training Project,No.2022YGJC001.
文摘BACKGROUND Integrating conventional ultrasound features with 2D shear wave elastography(2D-SWE)can potentially enhance preoperative hepatocellular carcinoma(HCC)predictions.AIM To develop a 2D-SWE-based predictive model for preoperative identification of HCC.METHODS A retrospective analysis of 884 patients who underwent liver resection and pathology evaluation from February 2021 to August 2023 was conducted at the Oriental Hepatobiliary Surgery Hospital.The patients were divided into the modeling group(n=720)and the control group(n=164).The study included conventional ultrasound,2D-SWE,and preoperative laboratory tests.Multiple logistic regression was used to identify independent predictive factors for RESULTS In the modeling group analysis,maximal elasticity(Emax)of tumors and their peripheries,platelet count,cirrhosis,and blood flow were independent risk indicators for malignancies.These factors yielded an area under the curve of 0.77(95%confidence interval:0.73-0.81)with 84%sensitivity and 61%specificity.The model demonstrated good calibration in both the construction and validation cohorts,as shown by the calibration graph and Hosmer-Lemeshow test(P=0.683 and P=0.658,respectively).Additionally,the mean elasticity(Emean)of the tumor periphery was identified as a risk factor for microvascular invasion(MVI)in malignant liver tumors(P=0.003).Patients receiving antiviral treatment differed significantly in platelet count(P=0.002),Emax of tumors(P=0.033),Emean of tumors(P=0.042),Emax at tumor periphery(P<0.001),and Emean at tumor periphery(P=0.003).CONCLUSION 2D-SWE’s hardness value serves as a valuable marker for enhancing the preoperative diagnosis of malignant liver lesions,correlating significantly with MVI and antiviral treatment efficacy.
基金funded by the National Natural Science Foundation of China(31471762)the Fundamental Research Funds for the Central Universities of China(2018NTST03)。
文摘Locusts are agricultural pests around the world. To cognize how locust distribution density and community structure are related to the hydrothermal and vegetation growth conditions of their habitats and thereby providing rapid and accurate warning of locust invasions, it is important to develop efficient and accurate techniques for acquiring locust information. In this paper, by analyzing the differences between the morphological features of Locusta migratoria manilensis and Oedaleus decorus asiaticus, we proposed a semi-automatic locust species and instar information detection model based on locust image segmentation, locust feature variable extraction and support vector machine(SVM) classification. And we subsequently examined its applicability and accuracy based on sample image data acquired in the field. Locust image segmentation experiment showed that the proposed GrabCut-based interactive segmentation method can be used to rapidly extract images of various locust body parts and exhibits excellent operability. In a locust feature variable extraction experiment, the textural, color and morphological features of various locust body parts were calculated. Based on the results, eight feature variables were selected to identify locust species and instars using outlier detection, variable function calculation and principal component analysis. An SVM-based locust classification experiment achieved a semi-automatic detection accuracy of 96.16% when a polynomial kernel function with a penalty factor parameter c of 2 040 and a gamma parameter g of 0.5 was used. The proposed detection model exhibits advantages such as high applicability and accuracy when it is used to identify locust instars of L. migratoria manilensis and O. decorus asiaticus, and it can also be used to identify other species of locusts.
基金supported by the National Basic Research Program of China (2007CB109301)the National Natural Science Foundation of China(40871 122)
文摘To better understand the interaction of N transformation and exogenous C source and manage N fertilization, the effects of glucose addition on N transformation were determined in paddy soils with a gradient of soil organic C content. Changes in N mineralization, nitrification and denitrification, as well as their response to glucose addition were measured by incubation experiments in paddy soils derived from Quaternary red clay in subtropical China. Mineralization and denitrification were changed in order of increasing soil fertilities： high 〉 middle 〉 low. During the first week of incubation, net N mineralization and denitrification rates in paddy soil with high fertility were 1.9 and 1.1 times of those in soil with middle fertility and 5.3 and 2.9 times of those in soil with low fertility, respectively. Addition of glucose decreased net N mineralization by approximately 78.8, 109.2 and 177.4% in soils with high, middle and low fertility, respectively. However, denitrification rates in soils with middle and low fertility were increased by 14.4 and 166.2% respectively. The highest nitrate content among the paddy soils tested was 0.62 mg kg-1 and the highest nitrification ratio was 0.33%. Addition of glucose had no obvious effects on nitrate content and nitrification ratio. It was suggested that the intensity of mineralization and denitrification was quite different in soils with different fertility, and increased with increasing soil organic C content. Addition of glucose decreased mineralization, but increased denitrification, and the shifts were greater in soil with low than in soil with high organic C content. Neither addition of glucose nor inherent soil organic C had obvious effects on nitrification in paddy soils tested.
基金Project supported by the National Natural Science Foundation of China (Grant No 10875012)the Natural Science Foundation of Shandong Province of China (Grant No Y2008A33)+1 种基金the Research Projects of Education Bureau of Shandong Province of China(Grant No J08L151)the Doctoral Foundation of Binzhou University, China (Grant No 2007Y02)
文摘In the framework of the gravity＇s rainbow, the asymptotic quasinormal modes of the modified Schwarzschild black holes undergoing a scalar perturbation are investigated. By using the monodromy method, we analytically calculated the asymptotic quasinormal frequencies, which depend on not only the mass parameter of the black hole, but also the particle＇s energy of the perturbation field. Meanwhile, the real parts of the asymptotic quasinormal modes can be expressed as TH In 3, which is consistent with Hod＇s conjecture. In addition, for the quantum corrected black hole, the area spacing is independent of the particle＇s energy, even though the area itself depends on the particle＇s energy. And that, by relating the area spectrum to loop quantum gravity, the Barbero-Immirzi parameter is given and it remains the same as from the usual black hole.
文摘Polyimide is a typical complex high-molecular polymer of imide monomers,which is widely used in the manufacture of parts for aerospace engineering.The hypervelocity impacts between the spacecraft and orbital debris can induce great damage to the spacecraft.In order to improve the safety of spacecraft,the characteristics of polyimide debris clouds produced by hypervelocity impact should be studied.Firstly,a Mie-Grüneisen equation of state based on the shock adiabat for polyimide,which describes the mechanical behavior in the numerical simulation,was obtained from hypervelocity impact experiments,then a 3-dimentional smoothed particle hydrodynamics program was compiled to numerically simulate the hypervelocity impact between aluminum projectiles(orbital debris)and polyimide targets with different impact velocities(3.km/s,5.km/s,8.km/s)and angles(0°,30°,45°,60°),finally typical shapes of debris clouds produced in different impact velocities and angles were collected from simulation results,the characteristics of which were systemically discussed.
文摘The study investigated the university students＇ attitudes towards the coexistence of the standard discourse and the emergent discourses through a questionnaire. 223 sophomores in Xinjiang Normal University participated in the survey. The results show that these students tend to accept the emergent discourses in terms of their new vocabulary words, such as ＂yumi＂. Although the standard discourse dominates the students＇ life, the emergent discourses are accepted and used by these students. With regard to the view to purify the Chinese language, human concern and tolerance for the coexistence of various discourses are suggested.
基金National Science and Technology Pillar Program, No.2012BAH48F01 Chinese Academy of Sciences Visiting Professorship for Senior International Scientists, No.2013T2Z0004+1 种基金 National Natural Science Foundation of China, No.41171165 No.41301204
文摘This study applies ArcGIS to analyze the spatiotemporal distribution of cultural sites in the Ill River Valley in northwestern China. It explores relationships between the sites＇ spatiotemporal evolutionary characteristics, human history, and the natural environment. The results indicate that the numbers and proportions of the sites, and the frequency of their oc- currence, exhibited an inverted V-shaped change trend during six historical periods. The ＂high in the east and low in the west＂ spatial distribution pattern of the first three periods shifted to the one the ＂high in the west and low in the east＂ during the latter three periods, demonstrating a change in the spatial center of gravity of human activities. The sites were mainly distributed on slopes of grades 1-5, with their proportions increasing from 75% during the Spring and Autumn Period （770 BC-476 BC）-Qin Dynasty （221 BC-207 BC） to 93.75% during the Qing Dynasty-Modern period. The concentrated distribution of site elevations shifted from grades 4-8 during the Spring and Autumn Period-Qin Dynasty, and the Western Han （206 BC-8）-Southern and Northern Dynasties （420-589）, to grades 1-4 during the latter three periods. The number of sites showed a shifting trend from high-elevation mountains and hills to low-elevation plains, and from high slopes to low slopes. In particular, the sites exhibited a special ＂moist＂ evolutionary pattern of migration from middle and upstream areas to downstream areas, as opposed to the migration pattern of sites located in typical arid areas. The study also considered factors influencing the distribution and spatiotemporal evolution of cultural sites, notably, human factors and natural factors.
基金supported by the National Natural Science Foundation of China(6057314,60773041)
文摘The modified version of Yahalom protocol improved by Burrows, Abradi, and Needham （BAN） still has security drawbacks. This study analyzed such flaws in a detailed way from the point of strand spaces, which is a novel method of analyzing protoeol＇s security. First, a mathematical model of BAN-Yahalom protocol is constructed. Second, penetrators＇ abilities are restricted with a rigorous and formalized definition. Moreover, to increase the security of this protocol against potential attackers in practice, a further improvement is made to the protocol. Future application of this re-improved protocol is also discussed.
基金Under the auspices of National Natural Science Foundation of China(No.41401176,41201550,41201114)New Starting Point of Beijing Union University(No.ZK10201406,ZK10201302)+1 种基金Humanities and Social Science Key Research Base of Zhejiang Province(Applied Economics at Zhejiang Gongshang University)(No.JYTyyjj20130105)Incubation Programme of Great Wall Scholars of Beijing Municipal University&College(No.IDHT20130322)
文摘Social vulnerability in this study represents the differences between the capacity to cope with natural hazards and disaster losses suffered within and between places.The assessment of social vulnerability has been recognized as a critical step in understanding natural hazard risks and enhancing effective response capabilities.This article presents an initial study of the social vulnerability of the Beijing-Tianjin-Hebei(B-T-H) Region in China.The goal is to replicate and test the applicability of the United States Social Vulnerability Index(So VI) method in a Chinese cultural context.Thirty-nine variables adapted from the So VI were collected in relation to two aspects:socioeconomic vulnerability and built environment vulnerability.Using factor analysis,seven factors were extracted from the variable set:the structure of social development,the level of economic and government financial strength,social justice and poverty,family structure,the intensity of space development,the status of residential housing and transportation,and building structure.Factor scores were summed to get the final So VI scores and the most and least vulnerable units were identified and mapped.The highest social vulnerability is concentrated in the northwest of the study area.The least socially vulnerable areas are mainly distributed in the Beijing,Tianjin and Shijiazhuang core urban peripheral and central city areas of the prefecture-level cities.The results show that this method is a useful tool for revealing places that have a high level of vulnerability,in other words,areas which are more likely to face significant challenges in coping with a large-scale event.These findings could provide a scientific basis for policy making and the implementation of disaster prevention and mitigation in China.
基金the Project of National Natural Science Foundation of China(Nos.21775036,21735002,21874035 and 22174044)。
文摘Simultaneous and quantitative detection of multiple exosomal micro RNAs(miRNAs)was successfully performed by a surface-enhanced Raman scattering(SERS)assay consisting of Raman probes and capture probes.In this design,the asymmetric core-shell structured Au@Au@Ag nanoparticles were first synthesized by layer-by-layer self-assembly method and modified with different Raman molecules and recognition sequences(poly A-DNA)to prepare the surface-enhanced Raman probes.Then,the streptavidinmodified magnetic beads were used to immobilize the biotinylated DNA capture sequences(biotin-DNA)to obtain capture probes.In the presence of target exosomal miRNAs,the Raman probes and capture probes could bind to the target exosomal miRNAs in the partial hybridization manner.Thus,the developed SERS sensor could indicate the target miRNAs levels in the buffer solution.Using breast cancerrelated miRNAs as model targets,the limits of detection of this sensor were determined to be 1.076 fmol/L for synthetic miR-21,0.068 fmol/L for synthetic miR-126,and 4.57 fmol/L for synthetic miR-1246,respectively.Such SERS sensors were further employed to detect the miR-21 in 20%human serum and the extraction solution of exosomes,respectively.Therefore,simultaneous and multiplex detection of cancerrelated exosomal miRNAs by this assay could provide new opportunities for further biomedical applications.
文摘It is noted that in the new Particle Data Group(PDG) version the rare decays of the Λ_(b) baryon have been revised with more accuracy. The new results show that most of the existing theoretical results on the process Λ_(b)→Λ_(γ) Lgbare larger than those of experiments. With the improved higher-order light-cone distribution amplitudes of the Λ baryon, we reanalyze the process in the framework of light-cone quantum chromodynamics sum rules and the branching ratio is estimated to be Br (Λ_(b)→Λ_(γ))=(7.38-0.39+0.40)×10^(16), which is consistent with the new experimental result. Furthermore, another process Λ_(b)→Λl+l- is also analyzed in the same frame. The final branching ratio is calculated to be Br (Λ_(b)→Λl+l-)=1.20×10^(-6), which is in good accordance with the data from the PDG and other theoretical predictions.
基金Supported by Department of Science and Technology of the Indian Ministry of Science and Technology(Grant No.SR/S0/AS-57/2004).
文摘Objective:To focus on the isolation and preliminary characterization of marine sponges associated Actinobacteria particularly Streptomyces species and also their antagonistic activities against bacterial and fungal pathogens.Methods:The sponges were collected from Kovalam and Vizhinjam port of south-west coast of Kerala,India.Isolation of strains was carried out from sponge extracts using international Streptomyces project media.For preliminary identification of the strains,morphological(mycelial colouration,soluble pigments,melanoid pigmentation,spore morphology),nutritional uptake(carbon utilisation,amonoacids influence,sodium chloride tolerance),physiological(pH,temperature)and chemotaxonomical characterization were done.Antimicrobial studies were also carried out for the selected strains.Results:With the help of the spicule structures,the collected marine sponges were identified as Callyspongia diffusa,Mycale mytilorum,Tedania anhelans and Dysidea fragilis.Nearly 94 strains were primarily isolated from these sponges and further they were sub-cultured using international Streptomyces project media.The strains exhibited different mycelial colouration(aerial and substrate),soluble and melanoid pigmentations.The strains possessed three types of sporophore morphology namely rectus flexibilis,spiral and retinaculiaperti.Among the 94 isolates,seven exhibited antibacterial and antifungal activities with maximal zone of inhibition of 30 mm.The nutritional,physiological and chemotaxonomical characteristic study helped in the conventional identification of the seven strains and they all suggest that the strains to be grouped under the genus Streptomyces.Conclusions:The present study clearly helps in the preliminary identification of the isolates associated with marine sponges.Antagonistic activities prove the production of antimicrobial metabolites against the pathogens.Marine sponges associated Streptomyces are universally well known for their synthesis of many bioactive compounds such as antibiotics,enzymes,enzyme inhibitors and food grade pigments.They also have certain biotechnological applications like probiotics and single cell proteins.These marine Streptomyces bioactive metabolites can be the futuristic solution for the dreadful diseases.
