检索结果-南通市图书馆

DnA-guided hepatitis b treatment,viral load is essential,but not sufficient

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of gastroenterology 2009年第4期15卷 423-430页

作者： Rafael bárcena Marugán Silvia garcía garzón Services of liver-gastroenterology Hospital Ramón y CajalUniversity of Alcalá Department of gastroenterology Hospital Universitario de GuadalajaraUniversity of Alcalá

Hepatitis b virus （HbV） infection is a global public health problem that concerns 350 million people worldwide. Individuals with chronic hepatitis b （Crib） are at increased risk of developing liver cirrhosis, hepatic de-compensation and hepatocellular carcinoma. To maintain undetectable viral load reduces chronic infection complications. There is no treatment that eradicates HbV infection. Current drugs are expensive, are associated with adverse events, and are of limited efficacy. Current guidelines try to standardize the clinical practice. nevertheless, controversy remains about management of asymptomatic patients with Crib who are hepatitis b e antigen （HbeAg）-positive with normal alanine aminotransferase, and what is the cut-off value of viral load to distinguish HbeAg- negative Crib patients and inactive carriers. We discuss in detail why DnA level alone is not sufficient to begin treatment of Crib.

关键词： Hepatitis b virus Viral DnA Alaninetransaminase Antiviral drug Hepatitis b e antigen Antiviral drug resistance

Influence of bimodal grain size distribution on the corrosion behavior of friction stir processed biodegradable AZ31 magnesium alloy

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 Magnesium and Alloys 2016年第1期4卷 68-76页

作者： n.Saikrishna g.Pradeep Kumar Reddy balakrishnan Munirathinam b.Ratna Sunil Department of Mechanical Engineering Rajiv Gandhi University of Knowledge Technologies(AP-IIIT)Nuzvid 521202India Department of Mechanical Engineering Vignana Bharathi Institute of TechnologyHyderabad 501301India Department of Metallurgical and Materials Engineering Indian Institute of Technology MadrasChennai 600036India

In the present study,AZ31 magnesium alloy sheets were processed by friction stir processing(FSP)to investigate the effect of the grain refinement and grain size distribution on the corrosion *** refinement from a starting size of 16.4±6.8µm to 3.2±1.2µm was attained after ***,bimodal grain size distribution was observed in the nugget zone with a combination of coarse(11.62±8.4µm)and fine grains(3.2±1.2µm).Due to the grain refinement,a slight improvement in the hardness was found in the nugget zone of FSPed *** bimodal grain size distribution in the stir zone showed pronounced influence on the corrosion rate of FSPed AZ31 as observed from the immersion and electrochemical *** the X-ray diffraction analysis,more amount of Mg(OH)_(2) was observed on FSPed AZ31 compared with the unprocessed *** measurements demonstrated the higher corrosion current density for FSPed AZ31(8.92×10^(−5)A/cm^(2))compared with the unprocessed condition(2.90×10^(−5)A/cm^(2))that can be attributed to the texture effect and large variations in the grain size which led to non-uniform galvanic intensities.

关键词： AZ31 Mg alloy biodegradable implants grain size distribution Corrosion Friction stir processing,texture

Quality vs. quantity of publications in nanotechnology field from the People’s Republic of China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Science bulletin 2008年第8期53卷 1272-1280页

作者： Ronald n. KOSTOFF Ryan b. bARTH Clifford g. Y. lAU Office of naval Research 875 N. Randolph St. Arlington 22217 VA USA DDl-OMnI Engineering LLC 8260 Greensboro Drive Suite 600 McLean VA USA Institute for Defense Analyses 4850 Mark Center Drive Alexandria VA USA

This study evaluates trends in quality of nanotechnology and nanoscience papers produced by au- thors from the People’s Republic of China (PRC). The metric used to gauge quality is ratio of highly cited nanotechnology papers to total nanotechnology papers produced in sequential time frames. The USA is both the most prolific nanotechnology publishing country and most represented country on highly cited nanotechnology papers (both in absolute numbers of highly cited papers and highly cited papers relative to total publications) over the 1998―2003 time frame, based on the SCI/SSCI databases. Some of the smaller hi-tech countries have relatively high ratios (~2) of highly cited papers to total publications (e.g. Denmark, netherlands, Switzerland). Countries that have exhibited rapid growth in SCI/SSCI nanotechnology paper production in recent years (e.g. PRC, South Korea) had ratios an order of magnitude less than that of the USA for 1998, but by 2003 had increased to about 20% that of the USA (~2.5). PRC and South Korea have climbed in the publications rankings from 6th and 9th in 1998, re- spectively, to 2nd and 6th in 2005, respectively. PRC’s ratio monotonically increased from 0.16 to 0.45 over the 1998―2003 period, and South Korea’s ratio increased from 0.11 to about 0.6 over that same period, indicating their papers are getting more and more citations proportionately. Thus, under rapid growth conditions, PRC and South Korea have been able to increase their share of participation in highly cited papers. As of 2003, PRC and South Korea have ratios comparable to nations like Japan, France, Italy, and Australia but not yet approaching those of the highly cited countries. none of the top ten publications producing institutions are from the USA, while all of the top ten highly cited publica- tions producers are from the USA. Over the 1998―2003 time period, the top six total publications pro- ducing institutions (globally) remained the same, with Chinese Academy of Scien

关键词：纳米技术纳米科学引用分析中国

Dynamic mechanical properties,deformation and damage mechanisms of eutectic high-entropy alloy AlCoCrFeni_(2.1)under plate impact

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第3期134卷 178-188页

作者： S.P.Zhao Z.D.Feng l.X.li X.J.Zhao l.lu S.Chen n.b.Zhang Y.Cai S.n.luo The Peac Institute of Multiscale Sciences ChengduChina Key laboratory of Advanced Technologies of Materials Ministry of EducationSouthwest Jiaotong UniversityChengduChina

Shock compression and spallation of a eutectic high-entropy alloy(HEA)AlCoCrFeni_(2.1)with lamellar structure are investigated via plate impact loading with free-surface velocity *** as-cast and postmortem samples are characterized with transmission electron microscopy,electron back-scatter diffraction and scanning electron *** accurate Hugoniot equation of state is ***-ter shock compression to∼12 gPa,both the l1_(2)and b_(2)phases retain their ordered *** dislocations in the{111}slip planes,stacking faults and deformation twins are found in the l1_(2)phase,along with fewer dislocations in the{110}slip bands in the b(2)***-induced deformation twin-ning within the l1_(2)phase of this HEA is observed as a new deformation mechanism under various load-ing *** spallation,both ductile and brittle damage modes are *** micro voids and cracks prefer to nucleate at the phase boundaries chiefly,then in the b(2)*** similar shock stress,the spall strength of AlCoCrFeni_(2.1)HEA is about 40%higher than those of other reported dual-phase HEAs due to the high stability of its semi-coherent phase boundaries.

关键词： High-entropy alloy Hugoniot Spall damage Microstructure

Stabilization of cubic ordering of zirconium dioxide nanoclusters on silicon with laser ablation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2007年第S1期26卷 10-13页

作者： KUZ'MEnKO A P PETERSOn M b KUZ'MEnKO n A ZAVODInSKY V g PUgACHEVSKY M A DObROMYSlOV M b laboratory Quantum Electronic & laser Technology Pacific National University Institute for Materials Science FEb RAS

Regimes of continuous and pulsed laser action on high-melting oxide compounds of ZrO2 were found with the aim of obtaining steady coatings on monocrystal silicon on laser ablation.X-ray phase analyses,scanning and atomic-force microscopy reveal that the coatings obtained are of nanocluster structure with the cubic *** this case the nanoclusters reach several hundreds of nanometers in *** assumption was made that on laser ablation of ZrO2 thermostabilization may take place where a minimum of the surface energy is attained just at cubic ordering.

关键词： laser ablation thermostabilization atomic-force microscopy nanocluster structure monocrystal silicon

A facile strategy for tuning the density of surface-grafted biomolecules for melt extrusion-based additive manufacturing applications

在线全文

学校读者我要写书评

暂无评论

bio-Design and Manufacturing 2024年第3期7卷 277-291页

作者： I.A.O.beeren g.Dos Santos P.J.Dijkstra C.Mota J.bauer H.Ferreira Rui l.Reis n.neves S.Camarero-Espinosa M.b.baker l.Moroni Department of Complex Tissue Regeneration MERLN Institute for Technology-Inspired Regenerative MedicineMaastricht University6229 ER MaastrichtThe Netherlands 3b’s Research group I3Bs–Research Institute on BiomaterialsBiodegradables and BiomimeticsHeadquarters of the European Institute of Excellence on Tissue Engineering and Regenerative MedicineUniversity of MinhoAveParkZona Industrial da Gandra4805-017 BarcoGuimarãesPortugal ICVS/3b’s-PT government Associate laboratory 4806-909 Braga/GuimarãesPortugal POlYMAT University of the Basque Country UPV/EHU20018 Donostia/San SebastiánSpain IKERbASQUE Basque Foundation for Science48009 BilbaoSpain

Melt extrusion-based additive manufacturing(ME-AM)is a promising technique to fabricate porous scaffolds for tissue engi-neering ***,most synthetic semicrystalline polymers do not possess the intrinsic biological activity required to control cell *** of biomolecules on polymeric surfaces of AM scaffolds enhances the bioactivity of a construct;however,there are limited strategies available to control the surface ***,we report a strategy to tune the surface density of bioactive groups by blending a low molecular weight poly(ε-caprolactone)5k(PCl5k)containing orthogonally reactive azide groups with an unfunctionalized high molecular weight PCl75k at different *** porous three-dimensional(3D)scaf-folds were then fabricated using a high weight percentage(75 wt.%)of the low molecular weight PCl *** a proof-of-concept test,we prepared films of three different mass ratios of low and high molecular weight polymers with a thermopress and reacted with an alkynated fluorescent model compound on the surface,yielding a density of 201-561 pmol/cm^(2).Subsequently,a bone morphogenetic protein 2(bMP-2)-derived peptide was grafted onto the films comprising different blend compositions,and the effect of peptide surface density on the osteogenic differentiation of human mesenchymal stromal cells(hMSCs)was *** two weeks of culturing in a basic medium,cells expressed higher levels of bMP receptor II(bMPRII)on films with the conjugated *** addition,we found that alkaline phosphatase activity was only significantly enhanced on films contain-ing the highest peptide density(i.e.,561 pmol/cm^(2)),indicating the importance of the surface *** together,these results emphasize that the density of surface peptides on cell differentiation must be considered at the cell-material ***,we have presented a viable strategy for ME-AM community that desires to tune the bulk and surface functionality via blending of(m

关键词： Additive manufacturing blending Surface functionalization Surface density Click chemistry Human

Classification of glaucoma in Retinal Images Using Efficientnetb4 Deep learning Model

在线全文

学校读者我要写书评

暂无评论

Computer Systems Science & Engineering 2022年第12期43卷 1041-1055页

作者： A.geetha n.b.Prakash national Engineering College Kovilpatti628502India

Today, many eye diseases jeopardize our everyday lives, such as Diabetic Retinopathy (DR), Age-related Macular Degeneration (AMD), and *** is an incurable and unavoidable eye disease that damages the vision ofoptic nerves and quality of life. Classification of glaucoma has been an active fieldof research for the past ten years. Several approaches for glaucoma classification areestablished, beginning with conventional segmentation methods and feature-extraction to deep-learning techniques such as Convolution neural networks (Cnn). Incontrast, Cnn classifies the input images directly using tuned parameters of convolution and pooling layers by extracting features. but, the volume of training datasetsdetermines the performance of the Cnn;the model trained with small datasets,overfit issues arise. Cnn has therefore developed with transfer learning. The primary aim of this study is to explore the potential of Efficientnet with transfer learning for the classification of glaucoma. The performance of the current workcompares with other models, namely Vgg16, InceptionV3, and Xception usingpublic datasets such as RIM-OnEV2 & V3, ORIgA, DRISHTI-gS1, HRF, andACRIMA. The dataset has split into training, validation, and testing with the ratioof 70:15:15. The assessment of the test dataset shows that the pre-trained Efficientnetb4 has achieved the highest performance value compared to other models listedabove. The proposed method achieved 99.38% accuracy and also better results forother metrics, such as sensitivity, specificity, precision, F1_score, Kappa score, andArea Under Curve (AUC) compared to other models.

关键词： Convolution neural network deep learning fundus image glaucoma image classification

RAPID SOlIDIFICATIOn OF HYPEREUTECTIC SIlVER-COPPERAllOY In DROP TUbE

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English letters) 1999年第3期12卷 251-258页

作者： Wang, n. Wei, b. northwestern Polytechnical Univ Xi'an China

The Ag-50wt%Cu hypereutectic alloy was solidified and investigated in a 3 m drop tube, and its nucleation and microstructure characteristics were explored also. The results showed that (1) with the decrease of droplet size, the structural morphology transforms from the dendrites with long trunk and thin short secondary arms to fine dendritic structures; (2) the dendritic growth is mainly controlled by solute diffusion within the whole undercooling regime, while the influence of thermal diffusion-controlled growth becomes stronger above a critical undercooling about 268 K; (3) the refinement of dendritic structure is caused by large amounts of nuclei within droplet; (4) when droplet diameter is smaller than 300 micron, the undercooling and growth velocity were estimated to be greater than 268 K and 290 mm/s respectively, while the solute trapping effect may occur.

关键词： Eutectics Morphology Rapid solidification

First-principles calculations of structural and electronic properties of Tl_xga_(1-x)As alloys

在线全文

学校读者我要写书评

暂无评论

Chinese Physics b 2016年第2期25卷 377-383页

作者： g. bilgec akyüz A. Y. Tunali S. E. gulebaglan n. b. Yurdasan Adnan Menderes University Faculty of Arts and Sciences Physics Department 09100 Aythn Turkey Dokuz Eylul University Faculty of Sciences Physics Department 35160 Izmir Turkey Yuzuncu YiI University Department of Electric Program Vacational School of Van 65080 Van Turkey

The zincblende ternary alloys Tl_xga_（1-x） As（0 〈 x 〈 1） are studied by numerical analysis based on the plane wave pseudopotential method within the density functional theory and the local density approximation. To model the alloys,16-atom supercells with the 2 × 2 × 2 dimensions are used and the dependency of the lattice parameter, bulk modulus,electronic structure, energy band gap, and optical bowing on the concentration x are analyzed. The results indicate that the ternary Tl_xga_（1-x） As alloys have an average band gap bowing parameter of 4.48 eV for semiconductor alloys and 2.412 eV for semimetals. It is found that the band gap bowing strongly depends on composition and alloying a small Tl content with gaAs produces important modifications in the band structures of the alloys.

关键词： methods of electronic structure calculations electron density of states and band structure of crys-talline solids electronic structure of disordered solid