检索结果-南通市图书馆

Tribological behaviour of sintered iron based self-lubricating composites

Friction 2017年第3期5卷 285-307页

作者： Jose Daniel Biasoli DE MELLO Cristiano BINDER Gisele HAMMES Roberto BINDER Aloisio Nelmo KLEIN laboratorio de Materiais(LabMat) Universidade Federal de Santa Catarina Florianópolis 88.040-900 SC BrazilLaboratorio de Tribologia e Materiais Universidade Federal de Uberl(a)ndia Uberl(a)ndia 38.400-902 MG Brazil laboratorio de Materiais(LabMat) Universidade Federal de Santa Catarina Florianópolis 88.040-900 SC Brazil Whirlpool Embraco Unit Joinville 89.219-900 SC Brazil

This work is a review of previous works, presenting and discussing the most important results obtained by an ongoing research program towards the development of innovative, low-cost, self-lubricating composites with a low friction coefficient and high mechanical strength and wear resistance. Special emphasis is given to uniaxial die pressing of solid lubricant particles mixed with matrix powders and to metal injection moulding associated with in situ generation of solid lubricant particles. Initially, a microstructural model/processing route (powder injection moulding followed by plasma-assisted debinding and sintering) produced a homogeneous dispersion of in situ generated solid lubricant particles. Micrometric nodules of graphite with diameter smaller than 20 μm were formed, constituting a nanostructured stacking of graphite foils with nanometric thickness. Micro Raman analysis indicated that the graphite nodules were composed of turbostratic 2D graphite having highly misaligned graphene planes separated by large interlamellae distance. Large interplanar distance between the graphene foils and misalignment of these foils were confirmed by transmission electron microscopy and were, probably, the origin of the outstandingly low dry friction coefficient (0.04). The effect of sintering temperature, precursor content, metallic matrix composition and surface finish is also reported. Furthermore, the influence of a double-pressing/double-sintering (DPDS) technique on the tribological performance of self-lubricating uniaxially die-pressed hBN + graphite-Fe-Si-C-Mo composite is also investigated. Moreover, the tribological behaviour of die-pressed Fe-Si-C matrix composites containing 5, 7.5 and 10 wt% solid lubricants (hBN and graphite) added during the mixing step is analysed in terms of mechanical properties and wear mechanisms. Finally, the synergy between solid lubricant particles dispersed in a metallic matrix and fluid lubricants in a cooperative mixed lubrication re

关键词： tribological behaviour powder metallurgy iron based self-lubricating composites turbostratic graphite

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrin-targeting with peptide-bioconjugated semiconductor-magnetic nanocrystalline heterostructures

引用

Nano Research 2016年第3期9卷 644-662页

作者： Gianpiero Valente Nicoletta Depalo Ivan de Paola Rosa Maria lacobazzi Nunzio Denora Valentino Laquintana Roberto Comparelli Emiliano Altamura Tiziana Latronico Michele Altomare Elisabetta Fanizza Marinella Striccoli Angela Agostiano Michele Saviano Annarita Del Gatto Laura Zaccaro Maria Lucia Curri Universita degli Studi di Bari Aldo Moro Dipartimento di Chimica Via Orabona 4 70125 - Bari Italy Istituto per i Processi Chimico-Fisici-CNR UOS Bari Via Orabona 4 70125 - Bari Italy Istituto di Biostrutture e Bioimmagini-CNR Via Mezzocannone 16 80134 - Napoli Italy Universita degli Studi di Bari Aldo Moro Dipartimento di Farmacia - Scienze del Farmaco Via Orabona 4 70125 - Bari Italy Universita degli Studi di BariAIdo Moro Dipartimento di Bioscienze Biotecnologie e Biofarmaceutica Via Orabona 4 70125 - Bari Italy lstituto di Cristallografia-CNR Via Amendola 122/0 70126 Bari Italy

Binary asymmetric nanocrystals （BNCs）, composed of a photoactive TiO2 nanorod joined with a superparamagnetic γ-Fe203 spherical domain, were embedded in polyethylene glycol modified phospholipid micelle and successfully bioconjugated to a suitably designed peptide containing an RGD motif. BNCs represent a relevant multifunctional nanomaterial, owing to the coexistence of two distinct domains in one particle, characterized by high photoactivity and magnetic properties, that is particularly suited for use as a phototherapy and hyperthermia agent as well as a magnetic probe in biological imaging. We selected the RGD motif in order to target integrin expressed on activated endothelial cells and several types of cancer cells. The prepared RGD-peptide/BNC conjugates, comprehensively monitored by using complementary optical and structural techniques, demon- strated a high stability and uniform dispersibility in biological media. The cytotoxicity of the RGD-peptide/BNC conjugates was studied in vitro. The cellular uptake of RGD-peptide conjugates in the cells, assessed by means of two distinct approaches, namely confocal microscopy analysis and emission spectroscopy determination in cell lysates, displayed selectivity of the RGD-peptide-BNC conjugate for the cw]33 integrin. These RGD-peptide-BNC conjugates have a high potential for theranostic treatment of cancer.

关键词： nanocrystallineheterostructures photoactive semiconductor magnetic nanostructure cyclic RGD peptide αvβ3 integrin active targeting

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Mitochondrial dysfunction as a target in spinal cord injury:intimate correlation between pathological processes and therapeutic approaches

引用

Neural Regeneration Research 2023年第10期18卷 2161-2166页

作者： Julieta Schmidt Héctor Ramiro Quintá Universidad de Buenos Aires CABAArgentina laboratorio de Medicina Experimental“Dr.J.Toblli” Hospital AlemánCABAArgentina Consejo Nacional de Investigaciones Científicas y Técnicas-CONICET CABAArgentina Rehabilitation Medicine Department University of MinnesotaTwin CitiesMINUSA

Traumatic spinal cord injuries interrupt the connection of all axonal projections with their neuronal targets below and above the lesion site. This interruption results in either temporary or permanent alterations in the locomotor, sensory, and autonomic functions. Damage in the spinal tissue prevents the re-growth of severed axons across the lesion and their reconnection with neuronal targets. Therefore, the absence of spontaneous repair leads to sustained impairment in voluntary control of movement below the injury. For decades, axonal regeneration and reconnection have been considered the opitome of spinal cord injury repair with the goal being the repair of the damaged long motor and sensory tracts in a complex process that involves:(1) resealing injured axons;(2) reconstructing the cytoskeletal structure inside axons;(3) re-establishing healthy growth cones;and(4) assembling axonal cargos. These biological processes require an efficient production of adenosine triphosphate, which is affected by mitochondrial dysfunction after spinal cord injury. From a pathological standpoint, during the secondary stage of spinal cord injury, mitochondrial homeostasis is disrupted, mainly in the distal segments of severed axons. This result in a reduction of adenosine triphosphate levels and subsequent inactivation of adenosine triphosphate-dependent ion pumps required for the regulation of ion concentrations and reuptake of neurotransmitters, such as glutamate. The consequences are calcium overload, reactive oxygen species formation, and excitotoxicity. These events are intimately related to the activation of necrotic and apoptotic cell death programs, and further exacerbate the secondary stage of the injury, being a hallmark of spinal cord injury. This is why restoring mitochondrial function during the early stage of secondary injury could represent a potentially effective therapeutic intervention to overcome the motor and sensory failure produced by spinal cord injury. This

关键词： adenosine triphosphate axonal regeneration creatine mitochondria dysfunction mitochondria spinal cord injury

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Methods to Be Developed for Some First Applications of Mitochondrial Filamentation

引用

Open Journal of Biophysics 2013年第1期3卷 51-53页

作者： Mario Gosalvez laboratorio y Servicio de Bioquímica Experimental clinica and Hospital Universitario Puerta de Hierro Madrid and Majadahonda Comunidad de Madrid Spain

The new field of mitochondrial filamentation and its first potential applications are just getting underway (1-7), following a series of pilot experiments in our laboratory over the past few decades (8-14). I should like to give a brief overview of the role that some new methods are playing in this emerging area of physiological bioenergetics, supported by a few references to our contributions as I scarcely have the faculties now to understand other specific contributions. This new field is brimming with promises for medicine, science and society, in general. I cannot and must not be concrete or comprehensive, because I honestly feel that it is now that matters are really beginning to take off, assisted by the most appropriate international capabilities.

关键词： Mitochondrial Filamentation Schizophrenic Psychoses Obesity

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Fruiting increases total content of flavonoids and antiproliferative effects of Cereus jamacaru D.C. cladodes in sarcoma 180 cells in vitro

引用

Asian Pacific Journal of Tropical Biomedicine 2019年第2期9卷 66-72页

作者： Jean Carlos Vencioneck Dutra Juda Ben-Hur de Oliveira Vanessa Silva dos Santos Paula Roberta Costalonga Pereira Jean Moises Ferreira Maria do Carmo Pimentel Batitucci laboratorio de Genetica Vegetal e Toxicologica Departamento de Ciencias BiologicasUniversidade Federal do Espirito Santo laboratorio de Biologia Molecular e Expressao Genica Departamento de Ciências BiologicasUniversidade Federal de Alagoas

Objective: To evaluate the influence of fruiting phenological stage on total flavonoid content, antioxidant activity, and antiproliferative effects of Cereus jamacaru(C. jamacaru)(mandacaru) cladodes and fruit. Methods: Fruit and cladodes at vegetative and fruiting stage of C. jamacaru were collected. The fruit was dissected and bark, pulp, and seeds were separated. Vegetative and fruiting cladodes, together with bark, pulp, and seeds were used to obtain five hydroalcoholic extracts. The extracts were investigated for total flavonoid content, using AlCl3 colorimetric method, antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging capacity and Fe^(2+) ion chelating activity, and in vitro antiproliferative effects(sarcoma 180 cells) by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2 H-tetrazolium bromide assay. Results: The extract of C. jamacaru cladodes at the fruiting stage showed higher flavonoid content compared to the other extracts. Seed extracts showed the highest antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) assays, and the extract of cladodes at vegetative stage showed better antioxidant activity in Fe^(2+) ion chelating activity. The extract of fruiting cladodes promoted higher antiproliferative effects compared to the other extracts. Conclusions: These findings suggest that fruiting increases the content of flavonoids and antiproliferative effects of C. jamacaru cladodes. Data reinforce the potential use of C. jamacaru cladodes and fruits as natural antioxidants and potent anticancer agent.

关键词： Mandacaru Flavonoid content DPPH ABTS Fe^(2+) ion chelating activity MTT assay Sarcoma 180 cells

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Atypical antipsychotics, more than just an antipsychotic

引用

Neural Regeneration Research 2020年第8期15卷 1477-1478页

作者： Hiram Tendilla-Beltrán Gonzalo Flores laboratorio de Fisiología de la Conducta Escuela Nacional de Ciencias BiológicasInstituto Politécnico NacionalCDMXMexico laboratorio de Neuropsiquiatría Instituto de FisiologíaBenemérita Universidad Autónoma de PueblaPueblaMexico

Antipsychotics are the prescribed drugs for *** first substance used for antipsychotic purposes appeared in 1952 and it was a general anesthetic:*** use of this drug was mainly because of its effects on violent behavior instead of sedation in patients,which“controls”the psychotic episodes and prevents psychosis *** then,pharmaceutical antipsychotics have been developed,producing second-generation or atypical *** drugs arose with the synthesis of clozapine in the late‘50s,which represented(and still represent)the“guide molecule”for the development of these substances,because of its effectiveness on the symptomatology of the disease.

关键词： prescribed synthesis drugs

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The reaction electronic flux in chemical reactions

引用

Science China Chemistry 2011年第12期54卷 1982-1988页

作者： CERON María Luisa ECHEGARAY Eleonora GUTIRREZ-OLIVA Soledad HERRERA Barbara TORO-LABB Alejandro laboratorio de Química Teorica Computacional(QTC) Facultad de Química Pontificia Universidad Catolica de Chile

The mechanism of a chemical reaction can be characterized in terms of chemical events that take place during the *** events are bond weakening/breaking and/or bond strengthening/*** reaction electronic flux(REF),a concept that identifies and rationalizes the electronic activity taking place along the reaction coordinate,has emerged recently as a powerful tool for characterizing the mechanism of chemical reactions.A quantitative theory introducing new descriptors for characterizing reaction mechanisms is presented in detail and three illustrative examples are *** nucleophilic substitution reactions the REF indicates that bond breaking or forming events may be leading the electronic activity whereas in the methanol decomposition reaction by copper oxide,the REF allows to discover that consecutive electronic reductions of copper together with bond breaking processes control the course of the reaction.

关键词：化学反应电子活动通量反应机制反应过程亲核取代分解反应断裂过程

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Phylogenetic endemism of the orchids of Megamexico reveals complementary areas for conservation

引用

Plant diversity 2022年第4期44卷 351-359页

作者： Brandon E.Gutierrez-Rodríguez Marilyn Vasquez-Cruz Victoria Sosa Instituto de Ecología AC Carretera Antigua a Coatepec 351El Haya91073 XalapaVeracruzMexico Unidad de Genomica Avanzada Laboratorio Nacional de Genomica para La BiodiversidadCentro de Investigaciony Estudios Avanzados IrapuatoLibramiento Norte Carretera Leon Km.9.636821 IrapuatoGuanajuatoMexico

Orchid diversity provides a unique opportunity to further our understanding of biotic and abiotic factors linked to patterns of richness,endemism,and phylogenetic endemism in many ***,orchid diversity is consistently threatened by illegal trade and habitat ***,we identified areas critical for orchid conservation in the biogeographic province of *** this purpose,we evaluated orchid endemism,phylogenetic diversity,and phylogenetic endemism within Megamexico and characterized orchid life *** results indicate that the majority of the regions with the highest estimates of endemism and phylogenetic endemism are in southern Mexico and northern Central America,mostly located on the Pacific side of *** the most important orchid lineages,several belong to epiphytic lineages such as Pleurothallidinae,Laeliinae and *** also found that species from diverse and distantly related lineages converge in montane forests where suitable substrates for epiphytes ***,the southernmost areas of phylogenetic diversity and endemism of Megamexico are in unprotected ***,we conclude that the most critical areas for orchid conservation in Megamexico are located in southern Mexico and northern Central *** recommend that these areas should be given priority by the Mexican system of natural protected areas as complementary conservation areas.

关键词： Epiphytes Geophytes Orchids Phylogenetic endemism Weighted endemism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

GC/MS: A Valid Tool for Soil Gas Hydrocarbons Speciation

引用

International Journal of Analytical Mass Spectrometry and Chromatography 2015年第3期3卷 54-62页

作者： Laura Clerici Emanuela Mongini Pasquale Robles Pierluisa Dellavedova Maria Antonietta De Gregorio U.O. laboratorio di Milano Sede Laboratoristica di via Juvara—Settore Laboratori—ARPA LOMBARDIA Milano Italia Settore Laboratori—ARPA LOMBARdiA Milano Italia

This work describes an alternative method based on GC/MS technique with SCAN-ion approach for speciation of hydrocarbons contained in soil gas matrices and sampled on solid sorbent tubes (coconut shell charcoal).

关键词： Hydrocarbons Soil Gas Matrices Solid Sorbent Tubes Soil Gas GC/MS

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Metabolic control of respiration and glycolysis of tumoral cells

引用

Advances in Biological Chemistry 2013年第1期3卷 86-89页

作者： Mario Gosalvez laboratorio y Servicio de Bioquímica Experimental Clinica and Hospital Universitario Puerta de Hierro (1970-2010) Madrid and Majadahonda Comunidad de Madrid Spain

The contribution of the author’s groups on the control of energy metabolism of cancer cells has been concisely reviewed. It is proposed that Otto Warburg’s “respiratory defect” of tumoral cells resides in an alteration of the recurrent filamentation cycle of mitochondria. These give those organelles an affinity lower for ADP than the affinity of the tumor cell isoenzyme of pyruvate kinase. These two findings may explain the essentials of the intimate mechanism of the aerobic glycolysis of cancer cells.

关键词： Energy Metabolism Cancer Mitochondrial Filamentation Glycolysis Respiration Metabolic Control

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：