检索结果-南通市图书馆

Phonon imaging in 3D with a fibre probe

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2021年第6期10卷 1007-1019页

作者： Salvatore La Cavera III Fernando Perez-cota Richard jSmith Matt Clark Optics and Photonics Group Faculty of EngineeringUniversity of NottinghamUniversity ParkNottingham NG72RDUK

We show for the first time that a single ultrasonic imaging fibre is capable of simultaneously accessing 3D spatial information and mechanical properties from microscopic *** novel measurement system consists of two ultrafast lasers that excite and detect high-frequency ultrasound from a nano-transducer that was fabricated onto the tip of a single-mode optical fibre.A signal processing technique was also developed to extract nanometric in-depth spatial measurements from GHz frequency acoustic waves,while still allowing Brillouin spectroscopy in the frequency ***-free and non-contact imaging performance was demonstrated on various polymer *** singular device is equipped with optical lateral resolution,2.5μm,and a depth-profiling precision of 45 nm provided by *** endoscopic potential for this device is exhibited by extrapolating the single fibre to tens of thousands of fibres in an imaging *** a device catalyses future phonon endomicroscopy technology that brings the prospect of label-free in vivo histology within reach.

关键词： fibre equipped acoustics

Cellular Auxin Homeostasis： Gatekeeping Is Housekeeping

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2012年第4期5卷 772-786页

作者： Michel ruiz Rosquete Department of Applied Genetics and Cell Biology University of Applied Life Sciences and Natural Resources (BOKU) 1190 Vienna Austria Department of Plant Systems Biology VIB and Department of Plant Biotechnology and Bioinformatics Ghent University 9052 Gent Belgium

The phytohormone auxin is essential for plant development and contributes to nearly every aspect of the plant life cycle. The spatio-temporal distribution of auxin depends on a complex interplay between auxin metabolism and cell-to-cell auxin transport. Auxin metabolism and transport are both crucial for plant development; however, it largely remains to be seen how these processes are integrated to ensure defined cellular auxin levels or even gradients within tissues or organs. In this review, we provide a glance at very diverse topics of auxin biology, such as biosynthesis, conjugation, oxidation, and transport of auxin. This broad, but certainly superficial, overview highlights the mutual importance of auxin metabolism and transport. Moreover, it allows pinpointing how auxin metabolism and transport get integrated to jointly regulate cellular auxin homeostasis. Even though these processes have been so far only separately studied, we assume that the phytohormonal crosstalk integrates and coordinates auxin metabolism and transport. Besides the integrative power of the global hormone signaling, we additionally introduce the hypothetical concept considering auxin transport components as gatekeepers for auxin responses.

关键词： auxin conjugation auxin homeostasis auxin metabolism auxin transport.

Detecting stable phase structures in EEG signals to classify brain activity amplitude patterns

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 Zhej.ang University-Science A(Applied Physics & Engineering) 2009年第10期10卷 1483-1491页

作者： Yusely ruiz Guang LI Walter j.FREEMAN Eduardo GONZALEZ Department of Biomedical Engineering Zhejiang University Hangzhou 310027China National Lab of Industrial Control Technology Institute of Cyber-Systems and ControlZhejiang UniversityHangzhou 310027China Department of Molecular&Cell Biology 101 Donner University of California at BerkeleyCA 94720-3206USA

Obtaining an electrocorticograms(ECoG)signal requires an invasive procedure in which brain activity is recorded from the cortical *** contrast,obtaining electroencephalograms(EEG)recordings requires the non-invasive procedure of recording the brain activity from the scalp surface,which allows EEG recordings to be performed more easily on healthy *** this work,a technique previously used to study spatial-temporal patterns of brain activity on animal ECoG was adapted for use on *** main issues are centered on solving the problems introduced by the increment on the interelectrode distance and the procedure to detect stable *** results showed that spatial patterns of beta and gamma activity can also be extracted from the EEG signal by using stable frames as time markers for feature *** adapted technique makes it possible to take advantage of the cognitive and phenomenological awareness of a normal healthy subject.

关键词： Electroencephalograms(EEG) Spatial-temporal pattem Stable phase structure Frames

Apples to oranges:environmentally derived,dynamic regulation of serotonin neuron subpopulations in adulthood?

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第9期20卷 2596-2597页

作者： Christopher j.O’Connell Matthew j.Robson Department of Genetics College of MedicineHarvard UniversityBostonMAUSA james L.Winkle College of Pharmacy Division of Pharmaceutical SciencesUniversity of CincinnatiCincinnatiOHUSA Neuroscience Graduate Program College of MedicineUniversity of CincinnatiCincinnatiOHUSA

Traumatic brain injury(TBI)is a public health problem with an undue economic burden that impacts nearly every age,ethnic,and gender group across the globe(Capizzi et al.,2020).TBIs are often sustained during a dynamic range of exposures to energetic environmental forces and as such outcomes are typically heterogeneous regarding severity and pathology(Capizzi et al.,2020).

关键词： sustained orange dynamic

Biodiversity, dynamics, and impact of chakras on the Ecuadorian Amazon

在线全文

学校读者我要写书评

暂无评论

journal of Plant Ecology 2019年第1期12卷 34-44页

作者： Roy R.Vera V j.Hugo cota-Sánchez jorge E.Grijalva Olmedo University of Saskatchewan Department of Biology112 Science PlaceSaskatoon SK S7N 5E2Canada University of Saskatchewan Department of Biology and W.P.Fraser Herbarium(SASK)112 Science PlaceSaskatoon SK S7N 5E2Canada Universidad Central del Ecuador Facultad de Medicina Veterinaria y ZootecniaJerónimo Leiton y Gatto SobralQuito 170521Ecuador Estación Experimental Santa Catalina Panamericana Sur Km1Instituto Nacional de Investigaciones AgropecuariasMejía 171101Ecuador

Aims Deforestation and biodiversity loss are two alarming,closely related problems,and the main factors triggering changes in land *** agricultural practices in the western Amazon Basin are known as chakras,and their structure and dynamics are seemingly optimal for forest ***,the variability in tree spe-cies and the degree of forest recovery after abandonment is poorly documented in this agroforestry system(AFS).The goals of this study were:(i)to investigate whether the different AFSs(chakras)preserve similar levels of forest diversity,(ii)to determine the effect of trans-formation of mature forests(MF)to chakras,in particular,forest alpha and beta diversity levels,and(iii)to investigate whether native tree species recovery leads to the original forest structure following chakra *** We assessed the floristic composition in three AFSs(cassava,corn,and cocoa),the secondary forest(SF),and the forest remnants in the buffer zone of the Northern Ecuadorian Amazon(NEA).All tree spe-cies with a diameter at breast height(dbh)≥10 cm were inventoried in 61 plots(0.28 ha average)representing 17.44 *** diversity was calculated in all systems to determine the levels of variabil-ity using species richness and the Shannon diversity ***,beta diversity was examined to evaluate the degree of dissimilarity among all AFSs with the MF in order to analyze changes in floristic *** divergence between the SF and the MF was ana-lyzed to ascertain forest recovery after chakra *** Findings A total of 4,060 trees(dbh≥10 cm)representing 109 species,96 genera,and 43 plant families were inventoried in 17.44 ha sampled in five systems in the buffer zone of the *** most dominant plant families were Arecaceae,Myristicaceae,Fabaceae,Meliaceae,and Malvaceae,and the most representative genera included Iriartea,Virola,Guarea,Ocotea,Cordia,Chrysophyllum,and *** MF in this zone is composed of 81 tree species circums

关键词： agroforestry biodiversity chakra climate change tropical forest

Temporal dynamics of neonatal hypoxic-ischemic encephalopathy injuries on magnetic resonance imaging

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第11期20卷 3144-3150页

作者： Holly Flyger Samantha j.Holdsworth Alistair j.Gunn Laura Bennet Hamid Abbasi Mātai Medical Research Institute Tairāwhiti GisborneNew Zealand Department of Anatomy&Medical Imaging Faculty of Medical and Health SciencesThe University of AucklandAucklandNew Zealand Center for Brain Research The University of AucklandAucklandNew Zealand Auckland Bioengineering Institute The University of AucklandAucklandNew Zealand

Moderate to severe perinatal hypoxic-ischemic encephalopathy occurs in~1 to 3/1000 live births in high-income countries and is associated with a significant risk of death or neurodevelopmental *** assessment is important to help identify highrisk infants,to help families,and to support appropriate interventions.A wide range of monitoring tools is available to assess changes over time,including urine and blood biomarkers,neurological examination,and *** present,magnetic resonance imaging is unique as although it is expensive and not suited to monitoring the early evolution of hypoxic-ischemic encephalopathy by a week of life it can provide direct insight into the anatomical changes in the brain after hypoxic-ischemic encephalopathy and so offers strong prognostic information on the long-term outcome after hypoxic-ischemic *** review investigated the temporal dynamics of neonatal hypoxic-ischemic encephalopathy injuries,with a particular emphasis on exploring the correlation between the prognostic implications of magnetic resonance imaging scans in the first week of life and their relationship to long-term outcome prediction,particularly for infants treated with therapeutic hypothermia.A comprehensive literature search,from 2016 to 2024,identified 20 pertinent *** review highlights that while the optimal timing of magnetic resonance imaging scans is not clear,overall,it suggests that magnetic resonance imaging within the first week of life provides strong prognostic *** challenges limit the timing consistency,particularly the need for intensive care and clinical ***,although most reports examined the prognostic value of scans taken between 4 and 10 days after birth,there is evidence from small numbers of cases that,at times,brain injury may continue to evolve for weeks after *** suggests that in the future it will be important to explore a wider range of times after hypo

关键词： magnetic resonance imaging neonatal hypoxic-ischemic encephalopathy neurodevelopmental outcomes prognostic biomarkers in neuroimaging scan timing therapeutic hypothermia

LP-SVR Model Selection Using an Inexact Globalized Quasi-Newton Strategy

在线全文

学校读者我要写书评

暂无评论

journal of Intelligent Learning Systems and Applications 2013年第1期5卷 19-28页

作者： Pablo Rivas-Perea j.an cota-ruiz j. A. Perez Venzor David Garcia Chaparro jose-Gerardo Rosiles Department of Computer Science Baylor University Waco TX USA Department of Electrical and Computer Engineering Auto- nomous University of Ciudad Juarez Ciudad Juárez Mexico Science Applications International Corporation El Paso TX USA.

In this paper we study the problem of model selection for a linear programming-based support vector machine for regression. We propose generalized method that is based on a quasi-Newton method that uses a globalization strategy and an inexact computation of first order information. We explore the case of two-class, multi-class, and regression problems. Simulation results among standard datasets suggest that the algorithm achieves insignificant variability when measuring residual statistical properties.

关键词： Hyper-Parameter Estimation Support Vector Regression Machine Learning Data Mining

Gene therapy for spinal muscular atrophy:perspectives on the possibility of optimizing SMN1 delivery to correct all neurological and systemic perturbations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第7期20卷 2011-2012页

作者： Sharon j.Brown Rafael j.Yáñez-Muñoz Heidi R.Fuller School of Pharmacy and Bioengineering Keele UniversityKeeleUK Wolfson Center for Inherited Neuromuscular Disease TORCH BuildingRJAH Orthopaedic HospitalOswestryUK *** Center of Gene and Cell TherapyDepartment of Biological SciencesSchool of Life Sciences and the EnvironmentRoyal Holloway University of LondonEghamUK

Spinal muscular atrophy(SMA)is a genetic condition that results in selective lower motor neuron loss with concomitant muscle weakness and *** genetic cause of SMA was understood in 1995 when loss or impairment of the survival motor neuron 1(SMN1)gene was identified as the main contributing factor(Lefebvre et al.,1995).This,in combination with the discovery that humans have a“back-up”gene,SMN2,which can produce low levels(approximately 10%)of the full-length functional SMN protein,has led to the generation of SMA-specific gene *** was traditionally classified according to age of symptom onset and developmental milestones achieved,with life expectancy and severity varying between ***,SMN2 copy number is used as a proxy for the prediction of disease severity,with higher SMN2 copy number typically being associated with reduced severity of SMA,although this relationship is not absolute:some individuals with low SMN2 copy number have less severe SMA phenotypes and vice ***,the etiology of SMA is further complicated by other factors,such as non-typical nucleotide variants and SMN2-independent modifiers of disease severity.

关键词： atrophy traditionally absolute

Retrieval of Elastic Green’s Tensor near a Cylindrical Inhomogeneity from Vector Correlations

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2008年第1期3卷 250-270页

作者： j.an AP´erez-ruiz Francisco Luzon Francisco j.Sanchez-Sesma Grupo de Geof´ısica Aplicada Departamento de F´ısica AplicadaUniversidad de Almer´ıaCa˜nada de San Urbano s/n04120-Almer´ıaSpain Departamento de Sismolog´ıa Instituto de IngenieriaUniversidad Nacional Aut´onoma de M´exicoCd.UniversitariaCircuito Escolar s/nCoyoac´an 04510M´exico D.F.Mexico.

Multiple scattering of elastic waves in realistic media makes that averagefield intensities or energy densities follow diffusive processes. In such regime the successiveP to S energy conversions by distributed random inhomogeneities give rise toequipartition which means that in the phase space the available elastic energy is distributedin averagewith equal amounts among the possible states of P and S waves. Insuch diffusive regime the P to S energy ratio equilibrates in an universal way independentof the particular details of the scattering. It has been demonstrated that averagingthe cross correlations at any two points of an elastic medium subjected to diffuse elasticwavefields leads to the emergence of the Green function, which is the wave fieldthat would be observed at one position if an impulsive load is applied at the other. Inthis work we study the problem of the retrieval of the 2D tensor elastodynamic Greenfunction in an infinite elastic space containing a circular cylinder inclusion. We illuminateisotropically the elastic spacewith plane waves. We assume the spectra for both Pand S waves uniform but such that the energy ratio ES/EP=(a/b)2, which is the onepredicted by equipartition theory in two-dimensions. We then show that the Fouriertransform of azimuthal average of the cross-correlation of motion between two pointswithin an elastic medium is proportional to the imaginary part of the exact Green tensorfunction between these points. The numerical results presented here point out thepossibility of detection and imaging of diffractors and resonant diffractors by crosscorrelation even in presence of attenuation exists.

关键词： Multiple scattering elastic waves elastic Green’s tensor