检索结果-南通市图书馆

Added value of ratio of cross diameters of the appendix in ultrasound diagnosis of acute appendicitis

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Surgery 2024年第1期16卷 21-28页

作者： Feng-wa Gu Si-Ze Wu Department of Ultrasound The First Affiliated Hospital of Hainan Medical UniversityHaikou 570102Hainan ProvinceChina

BACKGROUND The maximum outer diameter(MOD)of the appendix is an essential parameter for diagnosing acute appendicitis,but there is space for improvement in ultrasound(US)diagnostic *** To investigate whether combining the ratio of the cross diameters(RATiO)of the appendix with MOD of the appendix can enhance the diagnostic performance of acute *** A retrospective study was conducted,and medical records of 233 patients with acute appendicitis and 112 patients with a normal appendix were *** MOD and RATiO of the appendix were calculated and tested for their diagnostic performance of acute appendicitis,both individually and in *** The RATiO for a normal appendix was 1.32±0.16,while for acute appendicitis it was 1.09±*** cut-off value for RATiO was determined to be≤*** area under the receiver operating characteristic curve(AUC)for diagnosing acute appendicitis using RATiO≤1.18 and MOD>6 mm was 0.870 and 0.652,*** was a significant difference in AUC between RATiO≤1.18 and MOD>6 mm(Ping the combination of RATiO≤1.18 and MOD>6 mm with MOD>6 mm alone,the combination showed increased specificity,positive predictive value(PPV),and ***,the sensitivity and negative predictive value *** Combining RATiO of the appendix≤1.18 and MOD>6 mm can significantly improve the specificity,PPV,and AUC in the US diagnosis of acute appendicitis.

关键词： Acute appendicitis Diameter Ratio Diagnosis Ultrasound

Truly optimal semi-active damping to control free vibration of a single degree of freedom system

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2024年第2期14卷 142-145页

作者： Viet Duc la Ngoc Tuan Nguyen institute of Mechanics Vietnam Academy of Science and TechnologyHanoi 10000Vietnam Graduate University of Science and Technology Vietnam Academy of Science and TechnologyHanoi 10000Vietnam

This paper studies a single degree of freedom system under free vibration and controlled by a general semiactive damping.A general integral of squared error is considered as the performance index.A one-time switching damping controller is proposed and *** pontryagin maximum principle is used to prove that no other form of semi-active damping can provide the better performance than the proposed one-time switching damping.

关键词： Analytical optimization Quadratic integral Lyapunov equation Pontryagin maximum principle

A convolutional neural network to detect possible hidden data in spatial domain images

在线全文

学校读者我要写书评

暂无评论

Cybersecurity 2024年第1期7卷 37-52页

作者： Jean De la Croix Ntivuguruzwa Tohari Ahmad Department of informatics Institut Teknologi Sepuluh Nopember(ITS)Kampus ITS Keputih SukoliloSurabaya60111Indonesia African Center of Excellence in the internet of Things College of Science and TechnologyUniversity of Rwanda3900KigaliRwanda

Hiding secret data in digital multimedia has been essential to protect the ***,attackers with a steganalysis technique may break *** steganalysis methods have good results with conventional Machine Learning(ML)techniques;however,the introduction of Convolutional Neural Network(CNN),a deep learning paradigm,achieved better performance over the previously proposed ML-based *** the existing CNN-based approaches yield good results,they present performance issues in classification accuracy and stability in the network training *** research proposes a new method with a CNN architecture to improve the hidden data detection accuracy and the training phase stability in spatial domain *** proposed method comprises three phases:pre-processing,feature extraction,and ***,in the pre-processing phase,we use spatial rich model filters to enhance the noise within images altered by data hiding;secondly,in the feature extraction phase,we use two-dimensional depthwise separable convolutions to improve the signal-to-noise and regular convolutions to model local features;and finally,in the classification,we use multi-scale average pooling for local features aggregation and representability enhancement regardless of the input size variation,followed by three fully connected layers to form the final feature maps that we transform into class probabilities using the softmax *** results identify an improvement in the accuracy of the considered recent scheme ranging between 4.6 and 10.2%with reduced training time up to 30.81%.

关键词： information security Spatial domain steganalysis Deep learning Convolutional neural network infrastructure

Hydroxyapatite composites with carbon allotropes:Preparation,properties,and applications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第5期88卷 239-265页

作者： Boris i.Kharisov Oxana V.Kharissova Lucy T.González Yolanda Peña Méndez igor E.Uflyand idalia Gómez de la Fuente Universidad Autónoma de Nuevo León Ave.UniversidadCiudad UniversitariaSan Nicolás de los GarzaNuevo León 66455Mexico Tecnologico de Monterrey Escuela de Ingeniería y CienciasMonterreyNuevo Leon 64890Mexico Department of Chemistry Southern Federal UniversityRostov-on-DonRussia

Hydroxyapatite(HA)and its composites with inorganic additives,dopants,and polymers is a rapidly developing branch in the materials *** particular,carbon allotropes are widely used in these composites being widely applied for medical *** a gap of insufficient generalization of recent achievements in the field of the HA/Carbon composites,in this review we present the state of the art of the field of HA composites and hybrids with classic carbon allotropes and *** composites are known for carbon nanotubes,nanofibers,graphene and its oxidized forms,as well as,in a lesser grade,for graphite,fullerenes,nanodiamonds,carbon nanofoams,*** composites can be fabricated by a variety of classic and less-common methods,such as co-precipitation(with or without ultrasonic treatment),CVD,hot isostatic pressing,hydrothermal,spark plasma sintering,biomimetic mineralization,thermal and plasma spray,electrochemical and electrophoretic deposition,self-assembling,3D printing,electrospinning,and lyophilisation,among *** of various synthesis techniques can be also carried out for composite *** or synthetic HA can be used as it is for further interaction with carbon allotropes or it can be first prepared and then reacted with carbon counterpart;similarly,carbon allotropes can be introduced into the interaction with HA directly or they can be first synthesized,in particular from *** biocompatible composites can be produced in the form of coatings,powders,and scaffolds and can additionally contain quantitative amounts of third phases,frequently natural or synthetic *** these composites,especially with O-containing functionalizing groups,HA disadvantages could be considerably decreased with simultaneous enhancement of mechanical properties,becoming similar to human bone,chemical stability and biocompatibility,as well as possessing antibacterial ***→G reduction and higher HA decoration were obs

关键词： Hydroxyapatite Carbon nanotubes Graphene Quantum dots Fullerenes Nanodiamonds

ZnSb/Ti_(3)C_(2)T_(x)MXene van der waals heterojunction for flexible near-infrared photodetector arrays

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Semiconductors 2024年第5期45卷 99-105页

作者： Chuqiao Hu Ruiqing Chai Zhongming Wei la Li Guozhen Shen State Key laboratory for Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronic Engineering University of Chinese Academy of SciencesBeijing 100049China School of integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081China

Two-dimension(2D)van der waals heterojunction holds essential promise in achieving high-performance flexible near-infrared(NiR)***,we report the successful fabrication of ZnSb/Ti_(3)C_(2)T_(x)MXene based flexible NiR photodetector array via a facile photolithography *** single ZnSb/Ti_(3)C_(2)T_(x)photodetector exhibited a high light-to-dark current ratio of 4.98,fast response/recovery time(2.5/1.3 s)and excellent stability due to the tight connection between 2D ZnSb nanoplates and 2D Ti_(3)C_(2)T_(x)MXene nanoflakes,and the formed 2D van der waals *** polyethylene terephthalate(PET)substrate enables the ZnSb/Ti_(3)C_(2)T_(x)photodetector withstand bending such that stable photoelectrical properties with non-obvious change were maintained over 5000 bending ***,the ZnSb/Ti_(3)C_(2)T_(x)photodetectors were integrated into a 26×5 device array,realizing a NiR image sensing application.

关键词： ZnSb nanoplates Ti_(3)C_(2)T_(x)MXene van der waals heterojunction flexible photodetector image sensing

Woody plant taxonomic,functional,and phylogenetic diversity decrease along elevational gradients in Andean tropical montane forests:Environmental filtering and arrival of temperate taxa

在线全文

学校读者我要写书评

暂无评论

Plant Diversity 2024年第4期46卷 491-501页

作者： Guillermo Bañares-de-Dios Manuel J.Macía Gabriel Arellano Íñigo Granzow-de la Cerda Julia Vega-álvarez itziar Arnelas Carlos i.Espinosa Norma Salinas Luis Cayuela Departamento de Biología y Geología Física y Química InorgánicaUniversidad Rey Juan CarlosCalle Tulipán s/nMóstolesMadridES-28933Spain Departamento de Biología Área de BotánicaUniversidad Autónoma de MadridCalle Darwin 2MadridES-28049Spain Centro de investigación en Biodiversidad y Cambio Global(CiBC-UAM) Universidad Autónoma de MadridCalle Darwin 2MadridES-28049Spain Ecology and Evolutionary Biology University of MichiganAnn ArborMI 48109USA Oikobit LLC ***AlbuquerqueNM87120USA Real Jardín Botánico–CSiC Plaza Murillo 2MadridES-28014Spain Departamento de Biología Animal EcologíaParasitologíaEdafología y Química AgrícolaUniversidad de SalamancaCalle Donantes de Sangre s/nSalamancaES-37007Spain Departamento de Biodiversidad Ecología y EvoluciónUniversidad Complutense de MadridCalle JoséAntonio Nováis 12Ciudad UniversitariaES-28040Spain Departamento de Ciencias Biológicas y Agropecuarias Universidad Técnica Particular de LojaA.P.11-01-608 LojaEcuador Sección Química Pontificia Universidad Católica del PerúA.P.Lima 32LimaPeru ECi School of Geography and EnvironmentUniversity of OxfordOX13QYOxfordshireUnited Kingdom instituto de investigación en Cambio Global(iiCG-URJC) Universidad Rey Juan CarlosCalle Tulipán s/nMóstolesMadridES-28933Spain

Mountains are paramount for exploring biodiversity patterns due to the mosaic of topographies and climates encompassed over short *** research has traditionally focused on taxonomic diversity when investigating changes along elevational gradients,but other facets should be *** first time,we simultaneously assessed elevational trends in taxonomic,functional,and phylogenetic diversity of woody plants in Andean tropical montane forests and explored their underlying ecological and evolutionary *** investigation covered four transects(traversing ca.2200 m a.s.l.) encompassing 114 plots of 0.1 ha across a broad latitudinal range(ca.10°).Using Hill numbers to quantify abundance-based diversity among 37,869 individuals we observed a consistent decrease in taxonomic,functional,and phylogenetic diversity as elevation increased,although the decrease was less pronounced for higher Hill *** exception was a slight increase in phylogenetic diversity when dominant species were *** decrease in taxonomic and functional diversity might be attributed to an environmental filtering process towards highlands,where the increasingly harsher conditions exclude species and functional ***,the differences in steepness decrease between Hill orders suggest that rare species disproportionately contribute to functional *** phylogenetic diversity the shifting elevational trend between Hill orders indicates a greater than previously considered influence in central Andean highlands of tropical lowlands originated species with strong niche conservatism relative to distantly related temperate *** could be explained by a decreasing presence and abundance of temperate,extratropical taxa towards the central Andes relative to northern or southern Andes,where they are more prevalent.

关键词： Altitudinal gradients Andes Environmentalﬁltering Out of the Tropical Lowlands Functional rarity Tropical Niche Conservatism

The influence of Significant Public Health Events on Offline Consumption and its Pathways

在线全文

学校读者我要写书评

暂无评论

JOURNAL OF SYSTEMS SCiENCE AND SYSTEMS ENGiNEERiNG 2024年第5期33卷 627-648页

作者： Lu, Baile Zhou, Kewei Hao, Shuai Ta, la Dai, Hongyan Zhou, Weihua Natl Univ Def Technol Coll Syst Engn Changsha 410073 Peoples R China Cent Univ Finance & Econ Business Sch Beijing 100081 Peoples R China Southern Univ Sci & Technol Coll Business Dept Mkt & Operat Management Shenzhen 518055 Peoples R China Zhejiang Univ Sch Management Hangzhou 310058 Peoples R China

in the face of a significant public health event, consumers may either increase their panic buying or decrease their willingness to make purchases. This study focuses on the impact of a significant public health event on offline store sales and consumer consumption, utilizing data from chain convenience stores in Hefei and Wuhu during early 2019 and early 2020 in China. Employing a difference-in-differences model, the study investigates the effect of the significant public health event outbreak on weekly store sales, order numbers, and consumer consumption in terms of product quantities, transaction amount, average amount per order, and transaction frequency. Different from prior literature that finds hoarding behavior of consumers online, the findings of this paper indicate a significant reduction in stores' offline weekly sales and order numbers, as well as consumers' offline weekly consumption across the four dimensions, as a result of the significant public health event outbreak. Additionally, employing a mediation model, the study explores the pathway of population mobility through which the significant public health event adversely affects offline consumption. Furthermore, subset analysis is conducted for stores located in different areas and consumers with varying characteristics, revealing that the aforementioned conclusions predominantly apply to stores situated in office areas and residential areas, as well as consumers with either no apparent preference for different product categories or a noticeable preference for food.

关键词： Significant public health event offline consumption population mobility mediating effect HUMAN MOBiLiTY iMPACT

The earliest evidence for a microblade adaptation in the remote,high altitude regions of the Tibetan Plateau

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第5期67卷 1561-1573页

作者： Yingshuai JiN Xiaoling ZHANG Shejiang waNG Junyi GE Wei HE wa DA Yunyao TAN Ziyi YANG Christopher MORGAN Xing GAO institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of SciencesBeijing 100044China University of the Chinese Academy of Sciences Beijing 100049China Cultural Relics Conservation institute of the Xizang Autonomous Region Lhasa 850000China Nagqu Culture and Tourism Bureau Nagqu 852000China University of Nevada Reno 89557USA

Microblade assemblages are among the most common prehistoric archaeological materials found on the Tibetan Plateau(TP)and are thought to indicate large scale migration to and settlement of the *** microblade sites,however,have been systematically excavated,especially in the remotest,highest-elevation regions of the *** timing of the large-scale arrival,spread,and permanent settlement of people on the TP therefore remains *** this paper,we report on a recently excavated site,Locality 3 of the Nwya Devu Site(ND3),located at 4600 meters above sea level(masl),near the shore of Ngoin lake,on the interior *** analyses reveal a fairly typical microblade technological orientation and two types of microblade cores:wedge-shaped and semi-conical,which are similar to those found throughout North *** Optically Stimulated Luminescence(OSL)dating and AMS^(14)C dating,the age of ND3 ranges from 11 to 10 *** date range indicates ND3 is the oldest microblade site yet recorded in the remote,high-elevation regions of the TP and thus provides important information about when and how hunter-gatherers using microblades began exploiting the higher altitudes of the *** together,studies at ND3 and throughout the TP suggest that a microblade adaptation is associated with the first prolonged human occupation of the plateau and that microblades played a significant role in mediating the risks and facilitating the mobility necessary to permanently inhabit the TP.

关键词： The interior of Tibetan Plateau Nwya Devu locality 3 Microblade Early Holocene High altitude adaption

Strengthening and control of second-phase particle precipitation in ferritic/austenitic/martensitic heat-resistant alloys:a review

在线全文

学校读者我要写书评

暂无评论

Journal of iron and Steel Research international 2024年第1期31卷 3-23页

作者： Xue-cheng Peng Han-jie Guo Xin-fang Zhang Yi-wa Luo Ye Sun Jing Guo Rong-guang Yang Xiao-dan Zheng School of Metallurgical and Ecological Engineering University of Science and Technology Beijing(USTB)Beijing100083China Beijing Key laboratory of Special Melting and Preparation of High-End Metal Materials University of Science and Technology Beijing(USTB)Beijing100083China Beijing Shougang Gitane New MATERiALS Co. Ltd.Beijing102206China

Heat-resistant alloys with excellent mechanical properties are widely used in various fields,and further improvement in their properties is essential to meet the requirements in new-generation advanced supercritical boilers,nuclear reactors,superheaters,and other new materials *** effectively enhance the comprehensive performance of heat-resistant alloys,second-phase particle strengthening has been widely studied,and in the face of different service envi-ronments of advanced heat-resistant steels,the selection of suitable second-phase particles is essential to maximize the performance of these *** this end,three major types of reinforcing phases in heat-resistant alloys such as carbides,rare earth oxides,and intermetallic compounds are summarized.A comparative analysis of the precipitation behavior of the reinforcing phases with different types as well as the risks and means of controlling their use in service,is *** parameters for the application of various types of second-phase particles in heat-resistant alloys are provided to support the design and preparation of new ultrahigh-performance heat-resistant alloys.

关键词： Heat-resistant alloy Second-phase particle Carbide Rare earth oxide intermetallic compound Strengthening