Search Results - (Author, Cooperation:W. H. Zhang)

2018-08-04

Institute of Physics (IOP)

1757-8981

1757-899X

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

2018-10-12

Institute of Physics (IOP)

1755-1307

1755-1315

Geography

Geosciences

Physics

2014-02-14

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Aging/metabolism ; Animals ; Animals, Genetically Modified ; Caenorhabditis elegans/cytology/genetics/*metabolism/physiology ; Caenorhabditis elegans Proteins/genetics ; Death ; Energy Metabolism ; Environment ; Glyoxylates/metabolism ; Hermaphroditic Organisms ; *Longevity/genetics/physiology ; Male ; Mitochondria/*metabolism ; Models, Biological ; Muscles/cytology ; Mutation ; Oxidative Stress ; Receptor, Insulin/genetics ; Reproduction ; Stochastic Processes ; Superoxides/analysis/*metabolism ; Time Factors

2013-10-19

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2018-04-06

BMJ Publishing

2044-6055

Medicine

Open access, Epidemiology

2018-04-14

BMJ Publishing

2044-6055

Medicine

Open access

1365-2826

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

With the recent revelation of considerable peptidergic innervation of the anterior pituitary in several mammalian species, including man, it becomes imperative to elucidate the physiological significance of such a morphological entity. We addressed this issue by employing an anterior pituitary slice in vitro superfusion system coupled with electrical field stimulation. Anterior pituitary slices of 0.8 mm were perfused with Krebs-Ringer bicarbonate–bovine serum albumin buffer in a superfusion chamber for 30 min before electrical field stimulation. A square current of 30 mA, 10 Hz and 0.5 ms was then applied for 10 min. The perfusate was collected every 10 min and measured for adrenocorticotropic hormone (ACTH) by radio-immunoassay. It was found that under the experimental condition the basal release of ACTH was suppressed by electrical field stimulation of the nerve fibres in the anterior pituitary. Furthermore, vasopressin was added as a secretagogue. The suppression of ACTH by electrical field stimulation became even more marked. This is the first physiological evidence of the effect of stimulation of the nerve fibres innervating the anterior pituitary on its secretory activity.

Electronic Resource

1365-3040

Blackwell Publishing Journal Backfiles 1879-2005

Biology

In developing seeds of bean (Phaseolus vulgaris L.), phloem-imported assimilates (largely sucrose and potassium) are released from coats to seed apoplasm and subsequently retrieved by the dermal cell complexes of cotyledons. To investigate the mechanisms of K+ uptake by the cotyledons, protoplasts of dermal cell complexes were isolated and whole-cell currents across their plasma membranes were measured with the patch-clamp technique. A weakly rectified cation current displaying a voltage-dependent blockade by external Ca2+ and acidic pH, dominated the conductance of the protoplasts. The P haseolus v ulgaris Cotyledon Dermal-cell pH and Calcium-dependent Cation Conductance (Pv-CD-pHCaCC) was highly selective for K+ over Ca2+ and Cl–. For K+ current through Pv-CD-pHCaCC a sigmoid shaped current–voltage (I–V) curve was observed with negative conductance at voltages between −200 and −140 mV. This negative K+ conductance was Ca2+ dependent. With other univalent cations (Na+, Rb+, NH4+) the currents were smaller and were not Ca2+ dependent. Reversal potentials remained constant when external K+ was substituted with these cations, suggesting that Pv-CD-pHCaCC channels were non-selective. The Pv-CD-pHCaCC would provide a pathway for K+ and other univalent cation influx into developing cotyledons. These cation influxes could be co-ordinated with sucrose influx via pH and Ca2+dependence.

Electronic Resource

1615-1488

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract A convex programming optimizer called GMMA (Generalized Method of Moving Asymptotes) is presented in this paper. This method aims at solving engineering design problems including nonlinear equality and inequality constraints. The basic feature of this optimizer is that the efficient dual solution strategy together with the flexible GMMA approximation scheme are used. Especially, nonlinear equality constraints can be exactly satisfied by the intermediate solution of each explicit subproblem because their linearization is updated in an internal loop of the subproblem. This method will be illustrated by a hydrodynamic design application.

Electronic Resource

1615-1488

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract A practical tool is developed to deal with sizing sensitivity analysis of linear and geometrically nonlinear problems. Design variables are selected as cross-sectional areas of bar elements or the thickness of the membrane, beam, plate and shell elements. This tool is considered as a general open interface implemented outside the finite element package. It can extend existing finite element systems from pure structural analysis to engineering design capabilities. The formulation is based on the direct differentiation method. Numerical results are typically provided with the application of the ABAQUS code.

Electronic Resource

1615-1488

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract In this paper, a new efficient sensitivity analysis procedure is presented for the optimization of shell structures without access to the finite element source code. It is devised as a general interface tool to extend existing finite element systems from pure structural analysis to design capability. The implementation is performed based on the ABAQUS code. Kirchhoff flat shell elements are taken into account in the study with the element thickness as design variables. To ensure the performance and the validity of the proposed procedure, satisfactory sensitivity and optimization results are illustrated for numerical examples.

Electronic Resource

1615-1488

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract A mixed approximation method called DQA-GMMA is presented in this paper. This approximation uses the combination of Diagonal Quadratic Approximation (DQA) and the Generalized Method of the Moving Asymptotes (GMMA). It has the flexibility to deal with both monotonic and non-monotonic design functions. The convexity and the separable form of this approximation ensures the efficient solution of constructed optimization problem by dual approach. Truss geometry and configuration problems are solved by this method.

Electronic Resource