Which form of dopamine is the substrate for the human dopamine transporter: the cationic or the uncharged species?

The question of which is the active form of dopamine for the neuronal dopamine transporter is addressed in HEK-293 cells expressing the human dopamine transporter. The Km value for [3H]dopamine uptake fell sharply when the pH was increased from 6.0 to 7.4 and then changed less between pH 7.4 and 8.2. The KI for dopamine in inhibiting the cocaine analog [3H]2beta-carbomethoxy-3beta-(4-fluorophenyl)tropane binding displayed an identical pH dependence, suggesting that changes in uptake result from changes in dopamine recognition. Dopamine can exist in the anionic, neutral, cationic, or zwitterionic form, and the contribution of each form was calculated. The contribution of the anion is extremely low (相似文献   

Analysis of the Specific Features of Wear of the Working Rolls of the Finishing Group of Stands Under Conditions of the 1950 Mill at the Casting-Rolling Complex of the “VMZ” JSC

Metallurgist - We present the analysis of the mechanism of in-service wear of the working rolls of wide-band rolling mills on an example of a 1950 mill from the casting-rolling complex of the...     

SDRC Set the Conditions for Joining the Metals Business

In order to develop and use some of the metals resources such as tungsten, tin and antimony in a more rational way and control the export of these metals as well as promote the upgrading of the industries, China's State Development and Reform Commission (SDRC) recently set the conditions for the related metals business. This move, according to industry analysts, will further control the investment and make better use of the natural resources.     

Does the study of victimization revictimize the victims?

Scanning electron microscopy (SEM) has produced a wealth of novel images that have significantly complemented our perception of biological structure and function, derived initially from transmission electron microscopy (TEM) information. SEM is a surface imaging technology, and its impact at the subcellular level has been restricted by reduced resolution in comparison with TEM. Recently, SEM resolution has been considerably improved by the advent of high-brightness sources used in field-emission instruments (FEISEM) which have produced resolution of around 1 nm, virtually equivalent to TEM "working resolution." Here we review our findings in the use of FEISEM in the imaging of nuclear envelopes and their associated structures, such as nuclear pore complexes, and the relationships of structure and function. FEISEM allows the structurally orientated cell biologist to visualise, directly and in three dimensions, subcellular structure and its modulation with a view to understanding its functional significance.     

Present conditions of the industry and the facing problems

At present,most of the domestically pro-duced nonferrous metals are in the stateof over supply including copper,alumini-um,lead,zinc,nickel,tin,antimony andmagnesium.Among them,the productionof lead,nickel,tin and magnesium all ex-ceed demand by one or more times.Stricken by the world economic situation,particularly the economic crisis in theSoutheast Asian countries,all major metal     

Impact of the Travelling Magnetic Field on the Metallic Impurities During the Crystallization of Photovoltaic Silicon

Silicon is the most extensively studied semiconductor mainly owing to its wide applicability in the photovoltaic solar cell industry.However the qualily of Si photovoltaic cells depends on the purity of the material and on the grain structure of the ingot from which the wafers are cutting.The electrical performance of such materials,i.e.mainly their minority carrier lifetime,is closely related to metal impurities present in the feedstock or introduced during crystal growth.These impurities strongly interact with existing crystal defects to form complexes,accumulate at dislocations or grain boundaries in different forms,or even form silieide precipitates,which simultaneously contain several metal impurities.In such a context,it is necessary to control the segregation of impurities especially metallic in the grown ingot in order to optimize the cell properties as a function of the raw material purity.A new Bridgman set-up is developed in order to study the crystallization of photovoltaic Si under independently controlled solidification parameters growth rate,thermal gradient,purity and convection.Convection,either natural or forced,plays a very important role during the crystallization.Its intensity and flow pattern affect heat and mass transfer and,consequently,macrostructure and segregation in a solidified ingot.Here the convection can be controlled by a travelling magnetic field in order to homogenize or segregate the rejected impurities such as metallic elements.The effects of the magnetic field intensity and frequency on the segregation and crystalline structure will be presented.     

Improving the Corrosion Resistance of the Nickel–Tungsten Alloy by Optimization of the Electroplating Conditions

Nickel–tungsten (Ni–W) alloy coating was electrodeposited on the copper substrate by direct current voltammetry. The optimization of a free-ammonium bath for electrodeposition of Ni–W alloy coating was investigated. Experiments were focused on elucidating the effect of W concentration and operating conditions on the corrosion performance of the obtained Ni–W alloy coating. The corrosion behavior of the coatings was investigated by potentiodynamic polarization (Tafel) test. Experimental data such as corrosion current density, corrosion rate and polarization resistance indicated that the operating conditions used during the electroplating had significant effects on the corrosion parameters of the Ni–W alloy coating. The results showed that the highest corrosion resistance was obtained for the coating with 56.7 wt% tungsten (Ni/W ratio of 1:2.5) which was prepared at the current density of 3.8 A dm^?2. The increase in the corrosion resistance at the optimum current density was attributed to the lower interferences of the hydrogen evolution reaction. Energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) techniques were used to characterize the electrodeposited Ni–W alloy with the best anti-corrosion parameters.

     

Whither the Rorschach? An analysis of the evidence.

In the previous Special Section, the authors presented empirical evidence and logical analysis that were sufficient to demonstrate that the widespread use of the Rorschach in clinical, legal, forensic, and occupational settings is unwarranted on both scientific and ethical grounds (J. Hunsley and J. M. Bailey, see record 1999-11130-004). To expand on their analysis and to respond to issues raised in the previous and current Special Sections, they begin their article by examining a number of conceptual issues that are at the heart of the disagreements about the Rorschach. The focus is then shifted to the central issue of clinical utility, with an emphasis on why current research is insufficient to demonstrate the utility of the Rorschach. Next, the psychometric issues raised by I. B. Weiner (see record 2001-05665-002) are addressed and an alternative perspective on the psychometric viability of the Rorschach is provided. Finally, the authors conclude with some suggestions for future directions that must be taken in research to address the substantive concerns raised by Rorschach critics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Investigation of the Service Properties of the Electroslag Cast Metal

Ｉｎａｌｔｒａｄｉｔｉｏｎａｌｍｅｔｈｏｄｓｏｆｓｈａｐｅｄｃａｓｔｉｎｇ，ｍｅｔａｌｉｓｐｒｅｐａｒｅｄｉｎａｍｅｌｔｉｎｇｆｕｒｎａｃｅａｎｄｔｈｅｎｐｏｕｒｅｄｉｎｔｏａｍｏｌｄ．Ｓｅｃｏｎｄａｒｙｏｘｉｄａｔｉｏｎｏｃｃｕｒｓｂｅ－ｃａｕｓｅ...     

Correlation between the Sulphide Capacity Index and the Slag Basicity

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Phase equilibria in the tungsten-rich field of the W-Fe-Ni system in the 800–575°C

Conclusions In the W-Fe-Ni system subjected to annealing at 800 and 575°C, isostructural phases FeW and NiW form a continuous series of (Fe, Ni)W-type solid solutions.At 800 and 575°C, the phases NiW₂ and (Fe, Ni)W or a solid solution of nickel in the FeW phase are in equilibrium with the tungsten-based -solid solution and (Ni, Fe)W or a solid solution of iron in the NiW phase exists in equilibrium with the NiW₂ phase.It is assumed that an invariant eutectoid equilibrium + + (Fe, Ni)W exists in the system under study at a temperature of approximately 1130°C ( is the Fe₇W₆ phase; and and are the tungsten and the nickel-based solid solutions).Depending on the temperature, the phase composition of the binder present in the tungsten-based heavy alloys subjected to long-term annealing can undergo changes: at temperatures exceeding 1110°C, the binder consists of a nickel-based solid solution; in the 1100–1000°C range, an intermediate (Fe, Ni)W phase is present along with this phase; and at temperatures below 1000°C, it consists of the intermediate phases (Fe, Ni)W and NiW₂.Translated from Poroshkovaya Metallurgiya, No. 8(344), pp. 61–67, August, 1991.     

A Study on the Specific Heat of the Lanthanide Oxides

In this paper,we report the measurements of the specific heat of the lanthanide oxides(La_2O_3,CeO_2,Pr_6O_(11),Nd_2O_3,Sm_2O_3,Eu_2O_3,Gd_2O_3,Tb_4O_7,Dy_2O_3,Ho_2O_3,Er_2O_3,Tm_2O_3,Yb_2O_3,Lu_2O_3)from-150℃ to800℃ by using adiabatic scanning calorimeter.We found that chemical reactions occur during the heating pro-cess of initial La_2O_3 and Nd_2O_3 materials by using DTA and X-ray diffraction.The results of specific heatmeasurement show that except CeO_2 and Tb_4O_7,other twelve lanthanide oxides were accompanied withendothermal change and weight loss to a certain degree during the heating process.     

What is the source of the Fullerton-Cattell "principle"?

Points out that there is no basis for the common tendency of writers on psychophysics to attribute the statement "Equally often noticed differences are equal unless always or never noticed" to G. S. Fullerton and J. M. Cattell (1892). No such statement appears in their monograph and its spirit seems contrary to their work's goals. The 1st attribution of the statement to Fullerton and Cattell appears to have been made by L. L. Thurstone (1932). (PsycINFO Database Record (c) 2010 APA, all rights reserved)