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Virulence Markers in Staphylococcus aureus Strains Isolated from Hemodialysis Catheters of Mexican Patients

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Advances in Microbiology 2012年第4期2卷 476-487页

作者： Gloria Paniagua-Contreras Teresita Sainz-Espunes Eric Monroy-Perez Jose Raymundo Rodriguez-Moctezuma Diego Arenas-Aranda Erasmo Negrete-Abascal sergio vaca FES-Iztacala Universidad Nacional Autonoma de Mexico(UNAM)TlalnepantlaMéxico Ciencias Biológicas y de la Salud Universidad Autonoma Metropolitana(UAM)—XochimilcoCalzada del HuesoMéxico Departamento de Sistemas Biológicos División de Ciencias Biológicas y de la SaludUniversidad Autonoma Metropolitana(UAM)—XochimilcoCalzada del HuesoMéxico Hospital General Regional 72 Instituto Mexicano del Seguro SocialGustavo Baz Esquina F.GómezTlalnepantlaMéxico

Methicillin-resistant Staphylococcus aureus is an increasingly important cause of nosocomial bacterial infections worldwide. S. aureus is responsible for several pathologies, including skin infections, endocarditis, meningitis, deep-tissue ulcers, and sepsis. S. aureus biofilm formation on catheters and other medical devices is a major post-operative concern, because biofilms are often the source of persistent and difficult to treat bacterial infections. While catheter-related S. aureus infections have been reported, the strains responsible for these infections have not been genetically characterized. We genetically characterized S. aureus strains isolated from hemodialysis catheters in Mexican patients. The frequency of 35 genes coding for adhesins, toxins, and other virulence-associated products in the 55 isolated S. aureus strains was determined using PCR, while real-time PCR was used to examine the level of gene expression. Of the 55 S. aureus strains isolated from 109 patients, 45 (81.8%) were determined to be methicillin-resistant. The icaA, rbf, sarA, and agr genes are involved in biofilm formation and bacterial dispersion and were detected in 96.3%, 40.0%, 74.5%, and 100% of S. aureus strains, respectively, and 70.9% of the strains formed a detectable biofilm. Interestingly, 67.2% of the strains contained the icaA, agr, spa, clfA, sdrC, sdrD, sdrE, seg, seh, and sei genes, suggesting that this gene combination is important for successful catheter colonization. The results of this study provide significant insight into the virulence gene make-up of catheter-colonizing S. aureus strains, and will assist in developing a more targeted treatment approach for persistent S. aureus biofilm contamination of medical devices.

关键词： S.aureus Hemodialysis Catheter Genotyping

Adhesion of <i>Gallibacterium anatis</i>to Chicken Oropharyngeal Epithelial Cells and the Identification of Putative Fimbriae

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Advances in Microbiology 2012年第4期2卷 505-510页

作者： Mónica L. Salgado Lucio sergio vaca Candelario Vázquez Edgar Zenteno Ismael Rea Víctor M. Pérez-Márquez Erasmo Negrete-Abascal Biotecnología Veterinaria Tehuacán Mexico Carrera de Biología Facultad de Estudios Superiores Iztacala Universidad Nacional Autónoma de México (UNAM) Tlalnepantla México Centro de Investigaciones en Ciencias Microbiológicas Benemérita Universidad Autónoma de Puebla (BUAP) Puebla México Departamento de Bioquímica Facultad de Medicina Universidad Nacional Autónoma de México México City México

Microbial infections are typically initiated by the colonization of tissues by a specific mechanism that promotes adherence to host cells or tissues. In this work, we characterized the ability of Gallibacterium anatis F149T to express fimbriae that may be involved in mucosal attachment. Using transmission electron microscopy, the fimbriae-like structures could be observed on the surface of negatively stained G. anatis F149T, and these structures were further visualized after being released by physical shaking. When the fimbriae-like structures were separated by SDS-PAGE, the proteins comprising them were isolated and sized at 13 and 25 kDa. G. anatis F149T was able to adhere to chicken oropharyngeal epithelial cells. Adhesion could be completely inhibited by pretreatment of the bacterial cells with trypsin, whereas 25% inhibition was attained after pretreatment with an antiserum against the 13 kDa protein. We demonstrated by immuno-gold electron microscopy that the antibodies from the antiserum were specifically associated with the fimbria-like structures on G. anatis. These results indicated that G. anatis F149T expresses fimbriae that contribute to its adhesion to chicken oropharyngeal epithelial cells and may be important for colonization of the upper respiratory tract.

关键词： G. anatis Adhesion Fimbria Pili

Machine learning applications in stroke medicine:advancements,challenges,and future prospectives

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Neural Regeneration Research 2024年第4期19卷 769-773页

作者： Mario Daidone sergio Ferrantelli Antonino Tuttolomondo Internal Medicine and Stroke Care Ward Department of Health PromotionMother and Child CareInternal Medicine and Medical SpecialtiesUniversity of Palermo Molecular and Clinical Medicine PhD Program University of Palermo

Stroke is a leading cause of disability and mortality worldwide,necessitating the development of advanced technologies to improve its diagnosis,treatment,and patient outcomes.In recent years,machine learning techniques have emerged as promising tools in stroke medicine,enabling efficient analysis of large-scale datasets and facilitating personalized and precision medicine approaches.This abstract provides a comprehensive overview of machine learning’s applications,challenges,and future directions in stroke medicine.Recently introduced machine learning algorithms have been extensively employed in all the fields of stroke medicine.Machine learning models have demonstrated remarkable accuracy in imaging analysis,diagnosing stroke subtypes,risk stratifications,guiding medical treatment,and predicting patient prognosis.Despite the tremendous potential of machine learning in stroke medicine,several challenges must be addressed.These include the need for standardized and interoperable data collection,robust model validation and generalization,and the ethical considerations surrounding privacy and bias.In addition,integrating machine learning models into clinical workflows and establishing regulatory frameworks are critical for ensuring their widespread adoption and impact in routine stroke care.Machine learning promises to revolutionize stroke medicine by enabling precise diagnosis,tailored treatment selection,and improved prognostication.Continued research and collaboration among clinicians,researchers,and technologists are essential for overcoming challenges and realizing the full potential of machine learning in stroke care,ultimately leading to enhanced patient outcomes and quality of life.This review aims to summarize all the current implications of machine learning in stroke diagnosis,treatment,and prognostic evaluation.At the same time,another purpose of this paper is to explore all the future perspectives these techniques can provide in combating this disabling disease.

关键词： cerebrovascular disease deep learning machine learning reinforcement learning stroke stroke therapy supervised learning unsupervised learning

Spatial sensitivity to absorption changes for various near-infrared spectroscopy methods:A compendium review

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Journal of Innovative Optical Health Sciences 2024年第4期17卷 1-115页

作者： Giles Blaney Angelo Sassaroli sergio Fantini Department of Biomedical Engineering Tufts University 4 Colby StreetMedfordMA 02155USA

This compendium review focuses on the spatial distribution of sensitivity to localized absorption changes in optically diffuse media,particularly for measurements relevant to near-infrared spectroscopy.The three temporal domains,continuous wave,frequency domain,and time domain,each obtain different optical data types whose changes may be related to effective homogeneous changes in the absorption coefficient.Sensitivity is the relationship between a localized perturbation and the recovered effective homogeneous absorption change.Therefore,spatial sensitivity maps representing the perturbation location can be generated for the numerous optical data types in the three temporal domains.The review first presents a history of the past 30 years of work investigating this sensitivity in optically diffuse media.These works are experimental and theoretical,presenting one-,two-,and three-dimensional sensitivity maps for different Near-Infrared Spectroscopy methods,domains,and data types.Following this history,we present a compendium of sensitivity maps organized by temporal domain and then data type.This compendium provides a valuable tool to compare the spatial sensitivity of various measurement methods and parameters in one document.Methods for one to generate these maps are provided in Appendix A,including the code.This historical review and comprehensive sensitivity map compendium provides a single source researchers may use to visualize,investigate,compare,and generate sensitivity to localized absorption change maps.

关键词： Diffuse optics diffusion theory Monte Carlo spatial sensitivity absorption perturbations near-infrared spectroscopy continuous-wave frequency-domain time-domain

Nonlinear dynamics of the reversed shear Alfvén eigenmode in burning plasmas

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Plasma Science and Technology 2024年第5期26卷 1-16页

作者：王涛魏士朝 sergio BRIGUGLIO Gregorio VLAD Fulvio ZONCA 仇志勇 Institute for Fusion Theory and Simulation and School of Physics Zhejiang UniversityHangzhou 310027People’s Republic of China Center for Nonlinear Plasma Science ENEA C.R.FrascatiFrascati 00044Italy Fusion and Nuclear Safety Department ENEA C.R.FrascatiFrascati 00044Italy

In a tokamak fusion reactor operated at steady state,the equilibrium magnetic field is likely to have reversed shear in the core region,as the noninductive bootstrap current profile generally peaks off-axis.The reversed shear Alfvén eigenmode(RSAE)as a unique branch of the shear Alfvén wave in this equilibrium,can exist with a broad spectrum in wavenumber and frequency,and be resonantly driven unstable by energetic particles(EP).After briefly discussing the RSAE linear properties in burning plasma condition,we review several key topics of the nonlinear dynamics for the RSAE through both wave-EP resonance and wave-wave coupling channels,and illustrate their potentially important role in reactor-scale fusion plasmas.By means of simplified hybrid MHD-kinetic simulations,the RSAEs are shown to have typically broad phase space resonance structure with both circulating and trapped EP,as results of weak/vanishing magnetic shear and relatively low frequency.Through the route of wave-EP nonlinearity,the dominant saturation mechanism is mainly due to the transported resonant EP radially decoupling with the localized RSAE mode structure,and the resultant EP transport generally has a convective feature.The saturated RSAEs also undergo various nonlinear couplings with other collective oscillations.Two typical routes as parametric decay and modulational instability are studied using nonlinear gyrokinetic theory,and applied to the scenario of spontaneous excitation by a finite amplitude pump RSAE.Multiple RSAEs could naturally couple and induce the spectral energy cascade into a low frequency Alfvénic mode,which may effectively transfer the EP energy to fuel ions via collisionless Landau damping.Moreover,zero frequency zonal field structure could be spontaneously excited by modulation of the pump RSAE envelope,and may also lead to saturation of the pump RSAE by both scattering into stable domain and local distortion of the continuum structure.

关键词： reversed shear Alfvén eigenmode energetic particle nonlinear gyrokinetic theory saturation burning plasma

A new approach to pedestal differentiation for soil loss estimation-a case study from a burnt area in north-central Portugal

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Journal of Forestry Research 2024年第3期35卷 45-54页

作者： Frank G.A.Verheijen Martinho A.S.Martins sergio A.Prats Jan J.Keizer Centre for Environmental and Marine Studies(CESAM) Department Environment and PlanningUniversity of Aveiro3810-193 AveiroPortugal Mediterranean Institute for Agriculture Environment and Development(MED-CHANGE)Institute for Advanced Studies and ResearchUniversity of EvoraPolo da MitraAp.947006-554 EvoraPortugal GeoBiociencias Geotecnologias E Geoengenharias(GEOBIOTEC)Department Environment and PlanningUniversity of Aveiro3810-193 AveiroPortugal

Soil pedestals have long been used as qualitative indicators of soil splash erosion.In rangelands,plant-capped pedestals,generally grass tussocks,have also been used to quantitatively estimate soil loss since the first half of the twentieth century.In agricultural lands,forests,and bad-lands,stone-capped pedestals have been used as qualitative and semi-quantitative indicators of active,'extreme'erosion.Little work has been reported on using capstone pedestal data for quantifying soil loss.We postulate that three distinct capstone pedestal types may be present in any given location and that a detailed analysis of a pedestal height histogram may be used to recognize their populations.This analysis can subsequently inform if soil loss can be reliably estimated and if so,which of the existing methods using pedestal height data will provide more accurate results.The three proposed capstone pedestal types are:(1)neo-pedestals formed underneath surface stones exposed by(partial)removal of the soil surface cover;(2)endo-pedestals formed underneath stones that were buried in the soil but have been exposed by erosion;and(3)phoenix-pedestals formed underneath stones from collapsed pedestals.In the pedestal height histogram of any given location,a skew to smaller heights may indicate the existence of endo-and/or phoenix-pedestals,which may be revealed as a bi-(or tri)modal distribution when using a smaller bin size.This concept was applied to a case study where soil loss had been monitored for control plots and mulched plots during a 5-year period following wildfire in a eucalypt plantation.We measured pedestal heights and used methods to quantitatively assess soil loss from soil pedestal data in the available literature.Soil pedestal data at the end of the 5-year period under or overestimated soil loss in the control treatment,with results ranging from 60 to 115%of measured soil loss,depending on the method.It is postulated that phoenix-and endo-pedestals may be a driving factor behind the observed discrepancies.We discuss

关键词： Soil pedestals Mulch Wildfire Soil erosion Char

Greening the Belt and Road Initiative: Evidence from emergy evaluation of China’s provincial trade with ASEAN countries

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Fundamental Research 2024年第2期4卷 379-393页

作者： Xu Tian Joseph Sarkis Wei Chen Yong Geng Haozhi Pan Zuoxi Liu sergio Ulgiati SJTU-UNIDO Joint Institute of Inclusive and Sustainable Industrial Development School of International and Public AffairsShanghai Jiao Tong UniversityShanghai 200030China Worcester Polytechnic Institute Worcester MA 01609-2280USA School of Geography and Environment Shandong Normal UniversityJinan 250358China School of International and Public Affairs Shanghai Jiao Tong UniversityShanghai 200030China Key Laboratory of Clean Energy of Liaoning School of Energy and EnvironmentShenyang Aerospace UniversityShenyang 110136China Department of Science and Technology Parthenope University of NapoliNaples 80143Italy School of Environment Beijing Normal UniversityBeijing 100875China

The Belt and Road Initiative(BRI)is a central policy within China’s regional development and foreign trade strategy.Traditional trade has typically depended on economic valuation of resources,while the embedded environmental value is rarely considered.This situation exists in most BRI trade evaluations.To address BRI environmental sustainability issues,we consider the role of pivotal Chinese provinces and their key trade partners(ASEAN countries)as an illustration for the environmental value of resource exchanges.Emergy accounting is used as the valuation tool for a sample period of seventeen years.Key results include:(1)Emergy valuations show sustainability of sample provinces decreased over time;(2)ASEAN countries such as Indonesia,Malaysia,Singapore,Thailand,and Vietnam play significant resource roles for provincial economic systems;(3)Diverse trends in trade between pivotal provinces and ASEAN countries resulted in an unbalanced trade structure from trade.Policy implications are proposed to promote a more globally sustainable and fair trade using BRI as an established trade policy.

关键词： International trade Emergy Belt and road initiative Environmental sustainability Province

A new look at the first dinosaur discovered in Antarctica:reappraisal of Antarctopelta oliveroi(Ankylosauria:Parankylosauria)

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Advances in Polar Science 2024年第1期35卷 78-107页

作者： sergio SOTO ACUÑA Alexander OVARGAS Jonatan KALUZA Red Paleontológica U-Chile Departamento de BiologíaFacultad de CienciasUniversidad de ChileÑuñoa 7800003Chile Escuela de Geología Facultad de CienciasIngeniería y TecnologíaUniversidad MayorProvidenciaSantiago 7500994Chile Fundación de Historia Natural Félix de Azara Universidad MaimónidesBuenos Aires C1405Argentina Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET) Buenos Aires C1425FQBArgentina

The first dinosaur discovered in the Antarctic continent was the ankylosaur Antarctopelta oliveroi in the 1980s.Nevertheless,since then several hypotheses of phylogenetical relationships have been proposed because these have been depended on how the skeletal remains have been interpreted.The main obstacle for clarifying its phylogenetic position is that many portions of the skeleton remain unknown,in addition to the presence of unknown characters in typical ankylosaurs.Considered an ankylosaurid,nodosaurid,or even a chimaera,a recent proposal based on mostly complete material of a new ankylosaur from Chilean Patagonia provided support for a novel phylogenetic hypothesis:Antarctopelta and other southern ankylosaurs are an early branching clade,the Parankylosauria,whose origin probably dates to the Late Jurassic.In the light of this new view,a redescription of the available skeletal remains is provided together with a new reconstruction of the first Antarctic dinosaur known to the science community.

关键词： Antarctic Peninsula Biogeographic Weddellian Province Parankylosauria Antarctopelta

Stress tensors and quantification of fracture patterns to analyze connectivity and potential fluid flow in a mesa landform of the Northern Andes

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Journal of Mountain Science 2024年第1期21卷 271-291页

作者： GARCÍA-ARIAS sergio VELANDIA Francisco ALVAREZ Angélica SANABRIA-GÓMEZ JoséD TARAZONA Yessenia VARGAS María Camila Escuela de Geología Universidad Industrial de SantanderCra.27 Calle 9BucaramangaColombia Escuela de Física Universidad Industrial de SantanderCra.27 Calle 9BucaramangaColombia

This work applies stress tensors inversions and quantification of fracture patterns along the Mesa de Los Santos, in the Eastern Cordillera of Colombia, to better understand the potential fluid flow. It thus contributes to the conceptual hydrogeological model. The area was subdivided into three blocks, separated by the NW Potreros and the Los Santos faults, having minor inner faults of different orientations. This separation facilitates the analysis of the fractures measured in the field, which in general show high dip angles and a conjugate geometry in the northern block, tension fractures(Mode I) in the central block, and a random distribution in the southwestern block. WinTensor treatment of slickensides yielded a maximum horizontal stress(SHmax) of 111o, which coincides with the WNW-ESE tensor observed from the conjugate and tension joints. We then used Frac Pa Q to generate interpolation maps of fracture intensity and density. The maps show the highest values in the central block and the lowest in the northern block,where the precipitation is higher, causing intensive rock weathering and homogenization of the fracture planes. Although the highest values of connectivity by line are found to the south of the mesa, we suggest the possibility of greater flow from the recharge zone(NE) along bedding planes and open NW-SE fractures.

关键词： Mesa de Los Santos Colombia Win-Tensor FracPaQ Strike-slip faults Fractured aquifers