检索结果-南通市图书馆

Friction 2021年第2期9卷 415-428页

作者： Jose Enrique marTÍN-ALFONSO maría Jose marTÍN-ALFONSO Concepción VALENCIA maría Teresa CUBERES Department of Chemical Engineering and Materials Science Campus de“El Carmen”University of HuelvaChemical Product and Process Technology Research Center(Pro2TecS)Huelva 21071Spain Department of Applied Mechanics and Project Engineering University of Castilla-La ManchaAlmadén 13400Spain

This study investigates the development of novel montmorillonite/castor oil blends to formulate sustainable lubricating greases to promote the replacement of petrochemicals industry-derived materials by substances obtained from renewable ***,the effect of the thickener concentration on the rheological,chemical,thermal,tribological properties,and atomic force microscopy(AFM)microstructure of these systems were *** results showed that the C20A nanoclay content could be used to modulate the viscosity values,the linear viscoelastic functions,and tribological properties of these montmorillonite *** general,these gel-like dispersions exhibited remarkable lubricant properties;the samples showed values of the friction coefficient and wear scars similar or lower than those obtained with model bentonite grease.

关键词： lubricating greases nanoclay vegetable oil rheology tribology

Existence and Uniqueness to a Fully Nonlinear Version of the Loewner–Nirenberg Problem Dedicated to Celebrate the Sixtieth Anniversary of USTC

在线全文

学校读者我要写书评

暂无评论

Communications in Mathematics and Statistics 2018年第3期6卷 269-288页

作者： maría del mar González YanYan Li Luc Nguyen Departamento de Matemáticas Universidad Autónoma de MadridCampus de Cantoblanco28049 MadridSpain Department of Mathematics Hill CenterBusch CampusRutgers University110 Frelinghuysen RoadPiscatawayNJ 08854USA Mathematical Institute and St Edmund Hall University of OxfordAndrew Wiles BuildingRadcliffe Observatory QuarterWoodstock RoadOxford OX26GGUK

We consider the problem of finding on a given Euclidean domainof dimension n≥3 a complete conformally flat metric whose Schouten curvature A satisfies some equations of the form f(λ(−A))=*** generalizes a problem considered by Loewner and Nirenberg for the scalar *** prove the existence and uniqueness of such metric when the boundary δΩ is a smooth bounded hypersurface(of codimension one).When δΩ contains a compact smooth submanifold ∑ of higher codimension with δΩ\∑ being compact,we also give a‘sharp’condition for the divergence to infinity of the conformal factor near ∑ in terms of the codimension.

关键词： Fully nonlinear Loewner-Nirenberg problem Singular fully nonlinear Yamabe metrics Conformal invariance

Brain and spinal cord trauma:what we know about the therapeutic potential of insulin growth factor 1 gene therapy

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

Neural Regeneration Research 2023年第2期18卷 253-257页

作者： maría Jose Bellini Florencia Labombarda Lab de Bioquímica del Envejecimiento INIBIOLP-CONICETFacultad de Ciencias MedicinaUniversidad Nacional de La PlataLa PlataArgentina Laboratory of Neuroendocrine Biochemistry IBYME-CONICETBuenos AiresArgentina Department of Human Biochemistry Faculty of MedicineUniversidad de Buenos AiresBuenos AiresArgentina

Although little attention has been paid to cognitive and emotional dysfunctions observed in patients after spinal co rd injury,several reports have described impairments in cognitive *** group also has contributed significantly to the study of cognitive impairments in a rat model of spinal co rd *** findings are very significant because they demonstrate that cognitive and mood deficits are not induced by lifestyle changes,drugs of abuse,and combined *** are related to changes in brain structures involved in cognition and emotion,such as the *** spinal cord injury decreases neurogenesis,enhances glial reactivity leading to hippocampal neuroinflammation,and trigge rs cognitive *** brain distal abnormalities are recently called te rtiary *** that there is no treatment for Tertiary Damage,insulin growth factor 1 gene therapy emerges as a good *** growth factor 1 gene thera py recove rs neurogenesis and induces the polarization from pro-inflammato ry towards anti-inflammatory microglial phenotypes,which represents a potential strategy to treat the neuroinflammation that supports te rtiary *** growth factor 1 gene therapy can be extended to other central nervous system pathologies such as traumatic brain injury where the neuroinflammatory component is *** growth factor 1 gene therapy could emerge as a new therapeutic strategy for treating traumatic brain injury and spinal cord injury.

关键词： cognitive impairments gene therapy hippocampus insulin growth factor 1 microglial cells neurodegeneration neurogenesis neuroinflammation spinal cord injury traumatic brain injury

Weighted Inequalities for Fractional Type Operators with Some Homogeneous Kernels

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2013年第3期29卷 449-460页

作者： maría Silvina RIVEROS marta URCIUOLO FaMAF-UNC CIEM-CONICET Ciudad Universitaria

In this paper, we study integral operators of the formappropriate weighted BMO and weak type estimates for certain weights satisfying the above inequality. We also give a Coifman type estimate for these operators.

关键词： Fractional operators Calderon-Zygmund operators BMO Muckenhoupt weights

Heuristics of node selection criteria to assess robustness of world airport network

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2017年第4期30卷 1473-1480页

作者： Manel SORIA Oriol LORDAN Josmaría SALLAN Department of Physics Aeronautics Engineering Universitat Politecnica de Catalunya-BarcelonaTech Terrassa 08222 Spain Department of Management Universitat Politecnica de Catalunya-BarcelonaTech Terrassa 08222 Spain

The world airport network（WAN） is one of the networked infrastructures that shape today＇s economic and social activity, so its resilience against incidents affecting the WAN is an important problem. In this paper, the robustness of air route networks is extended by defining and testing several heuristics to define selection criteria to detect the critical nodes of the *** addition to heuristics based on genetic algorithms and simulated annealing, custom heuristics based on node damage and node betweenness are defined. The most effective heuristic is a multiattack heuristic combining both custom heuristics. Results obtained are of importance not only for advance in the understanding of the structure of complex networks, but also for critical node detection.

关键词： Adaptive strategy Air route networks Complex networks Intentional attacks Network robustness

Cellular automata model for traffic flow with safe driving conditions

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第5期23卷 216-226页

作者： maría Elena Lárraga Luis Alvarez-Icaza Instituto de Ingeniería Universidad Nacional Autónoma de México04510Coyoacán D.F.México

In this paper, a recently introduced cellular automata （CA） model is used for a statistical analysis of the inner micro-scopic structure of synchronized traffic flow. The analysis focuses on the formation and dissolution of clusters or platoons of vehicles, as the mechanism that causes the presence of this synchronized traffic state with a high flow. This platoon formation is one of the most interesting phenomena observed in traffic flows and plays an important role both in manual and automated highway systems （AHS）. Simulation results, obtained from a single-lane system under periodic boundary conditions indicate that in the density region where the synchronized state is observed, most vehicles travel together in pla- toons with approximately the same speed and small spatial distances. The examination of velocity variations and individual vehicle gaps shows that the flow corresponding to the synchronized state is stable, safe and highly correlated. Moreover, results indicate that the observed platoon formation in real traffic is reproduced in simulations by the relation between vehicle headway and velocity that is embedded in the dynamics definition of the CA model.

关键词： traffic flow models synchronized traffic cellular automata platoons formation

Potential of RP-UHPLC-DAD-MS for the qualitative and quantitative analysis of sofosbuvir in film coated tablets and profiling degradants

在线全文

学校读者我要写书评

暂无评论

Journal of Pharmaceutical Analysis 2017年第4期7卷 208-213页

作者： maría del mar Contreras Aránzazu Morales-Soto Antonio Segura-Carretero Javier Valverde Department of Analytical Chemistry Faculty of SciencesUniversity of GranadaAvenida Fuentenueva s/n18071 GranadaSpain Research and Development Functional Food Centre (CIDAF) Bioregión BuildingHealth Science Technological ParkAvda. Del Conocimiento s/n18016 GranadaSpain

Sofosbuvir is one of the new direct-acting antiviral drugs against hepatitis C virus(HCV) infection. This drug has recently been launched into the market, and generic versions of the medication are expected to be produced by local drug producers in some countries. Therefore, new methods are required to control sofosbuvir in pharmaceuticals. In the present study, a new method based on reversed phase(RP)-ultra-high performance liquid chromatography(UHPLC) coupled to diode array detection(DAD) and mass spectrometry(MS) was developed to facilitate the qualitative and quantitative analysis of sofosbuvir in film coated tablets. A wavelength of 260 nm was selected to perform a cost-effective quantification and the method showed adequate linearity,with an R^2 value of 0.9998, and acceptable values of accuracy(75%–102%) and precision(residual standard deviation < 5%). The detection and quantification limits were 0.07 μg/mL and 0.36 μg/mL, ***, the use of high-resolution MS enabled us to ensure the specificity, check impurities and better sensitivity. Therefore, this methodology promises to be suitable not only for the routine analysis of sofosbuvir in pharmaceutical dosage forms, but also for potential degradants.

关键词： Film coated tablets Mass spectrometry RP-UHPLC Sofosbuvir

Glutamine is highly effective in preventing in vivo cobalt-induced oxidative stress in rat liver

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2005年第23期11卷 3533-3538页

作者： Soledad Gonzales Ariel H.Polizio maría A.Erario maría L.Tomaro Departamento de Química Biológica

AIM: To evaluate the in vivo effect of glutamine on cobaltgenerated oxidative stress and (HO-1) induction in rat ***: Fasted female Wistar rats received a single injection of cobalt chloride (375 μmol/kg body weight) and then were killed at different times. Lipid peroxidation and soluble and enzymatic antioxidant defense system (reduced glutathione (GSH), catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD)) were measured in liver homogenates. Ferritin and ferritin iron contents as well as heme oxygenase-1 (HO-1) activity and expression were also determined. The antioxidant properties of glutamine (Gin) were also evaluated. RESULTS: Cobalt chloride increased lipid peroxidation (50% over control values) 1 h after treatment. GSH reached a minimum at 3 h (40%) increasing thereafter. Twelve hours after CoCl2 injection, the antioxidant enzymes CAT, GSH-Px and SOD also diminished by about 30%. Heme oxygenase-1 induction was observed 6 h after treatment reaching a maximum value of 14-fold over the controls, 12 h after cobalt treatment. A 1.7-fold increase in ferritin and ferritin-bound iron 24 h after treatment were also obtained. Administration of glutamine (300 mg/kg body weight) by gavage 24 h before CoCl2 treatment entirely prevented the increase in thiobarbituric acid reactive substances (TBARS) content, the decrease in GSH levels, and partially reverted heme oxygenase-1 induction. CONCLUSION: These results suggested that a natural product such as glutamine prevents glutathione depletion and consequently heme oxygenase induction.

关键词： Oxidative stress Heme oxygenase Glutathione Glutamine Iron Liver

Antioxidant role of heme oxygenase-1 in prehepatic portal hypertensive rats

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

World Journal of Gastroenterology 2006年第26期12卷 4149-4155页

作者： Soledad Gonzales maría Julia Pérez Juan C Perazzo maría Luján Tomaro Department of Biological Chemistry School of Pharmacy and Biochemistry University of Buenos AiresBuenos Aires 1113Argentina Laboratory of Portal Hypertension Department of Biological Science School of Pharmacy and BiochemistryUniversity of Buenos AiresBuenos Aires 1113Argentina

AIM： To study the effect of bilirubin on the oxidative liver status and the activity and expression of heine oxygenase-1 （HO-1） in rat liver injury induced by prehepatic portal hypertension. METHODS： Wistar male rats, weighing 200-250 g, were divided at random into two groups： one group with prehepatic portal hypertension （PH） induced by regulated prehepatic portal vein ligation （PPVL） and the other group corresponded to sham operated rats. Portal pressure, oxidative stress parameters, antioxidant enzymes, HO-1 activity and expression and hepatic sinusoidal vasodilatation were measured. RESULTS： In PPVL rats oxidative stress was evidenced by a marked increase in thiobarbituric acid reactive substances （TBARS） content and a decrease in reduced glutathione （GSH） levels. The activities of liver antioxidant enzymes, superoxide dismutase （SOD）, catalase （CAT） and glutathione peroxidase （GSH-Px） were also diminished while activity and expression of HO-1 were enhanced. Administration of bilirubin （5μmol/kg body weight） 24 h before the end of the experiment entirely prevented all these effects. Pretreatment with Sn-protoporphyrin IX （Sn-PPIX）（100 μg/kg body weight, i.p.）, a potent inhibitor of HO, completely abolished the oxidative stress and provoked a slight decrease in liver GSH levels as well as an increase in lipid peroxidation. Besides, carbon monoxide, another heme catabolic product, induced a significant increase in sinusoidal hepatic areas in PPVL group. Pretreatment of PPVL rats with Sn-PPIX totally prevented this effect CONCLUSION： These results suggest a beneficial role of HO-1 overexpression in prehepatic portal hypertensive rats.

关键词： Heme oxygenase-1 Portal hypertensive rats Liver oxidative stress

Modelling and simulation of flight control electromechanical actuators with special focus on model architecting, multidisciplinary effects and power flows

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

Chinese Journal of Aeronautics 2017年第1期30卷 47-65页

作者： Fu Jian Jean-Charles maré Fu Yongling School of Mechanical Engineering and Automation Beihang University Beijing 100083 China Institut Clement Ader (CNRS UMR 5312) INSA-Toulouse Toulouse 31077 France

In the aerospace field, electromechanical actuators are increasingly being implemented in place of conventional hydraulic actuators. For safety-critical embedded actuation applications like flight controls, the use of electromechanical actuators introduces specific issues related to thermal balance, reflected inertia, parasitic motion due to compliance and response to failure. Unfortunately, the physical effects governing the actuator behaviour are multidisciplinary, coupled and nonlinear. Although numerous multi-domain and system-level simulation packages are now available on the market, these effects are rarely addressed as a whole because of a lack of scientific approaches for model architecting, multi-purpose incremental modelling and judicious model implementation. In this publication, virtual prototyping of electromechanical actuators is addressed using the Bond-Graph formalism. New approaches are proposed to enable incremental modelling,thermal balance analysis, response to free-run or jamming faults, impact of compliance on parasitic motion, and influence of temperature. A special focus is placed on friction and compliance of the mechanical transmission with fault injection and temperature dependence. Aileron actuation is used to highlight the proposals for control design, energy consumption and thermal analysis, power network pollution analysis and fault response.

关键词： Bond Graph Electro-hydrostatic actuator Electromechanical actuator More electric aircraft Modelling Power-by-wire Power loss Simulation