International Journal of Science
Volume:3 Issue: 1, 2002

Thyrotropin-releasing hormone(TRH) and its receptors are widely distributed throughout the hippocampus. It plays some role in neurotransmission and neuromodulation and may affect on learning and memory functions. In the present study the effects of intrahippocampal microinjections of TRH(1,3 and 10?g/?l) on the trace classical conditioning of the rabbit,s eyeblink were examined. Five minutes before starting any training sessions, 1? l of TRH solution was injected through an implanted cannula into the CA1 area of hippocampus. The results indicate that TRH, dose dependently, increased the percentage of conditioned responses and shortened the latency of responses, compared with those in the control group. Therefore, it seems that TRH facilitates eyeblink trace conditioning and it may have an improving action on learning and memory retention

Cadmium (Cd) is an industrial and environmental pollutant. It has toxic effects on root tip growth and morphogenesis of onion (Allium cepa L.). Onion roots were germinated in 0, 2, 5, 10, 25, 50, 100, 200 g/ml doses of CdSO4 salt. Then root tips were fixed, dehydrated and paraffin embedded. Afterwards, material was sectioned on a microtom (7 m thickness) and stained by Acridine orange fluorescent dye and cytochemical methods for DNA and RNA staining. Results show that Cd induces morphological changes such as cell vacuolization, nucleus and cytoplasm condensation and nucleus margination. It also causes decreases nucleoplasmic ratio and cell death induction. It was also observed that Cd toxicity has a threshold level (10-25?g/ml concentrations). In doses higher than this threshold, cells are irreversibly committed to death. Therefore in concentrations lower than 25 g/ml, the mode of cell death is apoptotic-like cytological features and necrosis happens in higher concentrations.

Electrochemical (EC) data, in particular, when the magnitude of current is in range of nano and pico ampere, suffers from existence of environmental noises. In this work, a new modified SW voltammetric method for determination of Se(IV) is presented. Where signal-to-noise ratio has significantly (near to 620 times) increased by application of discrete Fast Fourier Formation (FFT) method, background subtraction and two-dimensional integration of the electrode response over a selected potential range and time window. Also, the detection method can be used for direct and indirect determination of Se(IV) ions by measuring the changes in SW voltammogram (or admittance) of an gold ultramicroelectrode (in 0.05 M H3PO4 solution) caused by redox reaction or just adsorption of the Se(IV) ion on the electrode surface. In indirect detection, the analyte signal was calculated based on admittance changes related to inhibition of oxygen adsorption (by adsorbed of Se(IV) ions). Direct measurement was carried out on an anodic stripping mode, after accumulation of the analytes on the electrode surface for 50 to 100 ms. In method, removal of oxygen from the studied solutions is not required. Calibration plots are given for solutions containing 10-8–10-7 M and 10-7–10-6 M of Se(IV) The limit of detection is calculated to be 2.5? 10-9 M. The relative standard deviation at concentration 3?10-8 M is 6 % for 5 reported measurements.

Detail description of texture and composition of 880 samples from Upper Red Formation sandstones in central part of its basin directed to identification of major petrofacies. On this basis, 17 petrofacies in the south and 16 petrofacies in the north successions were distinguished and described comprehensively. Major components variation of petrofacies through measured sections is used for analysis of source region and diagenetic history. A distinct diversity in the source rocks composition is indicated from component variation analysis. Major characteristic of the petrofacies and detrital mode analysis of sandstones indicate deposition in a back arc setting in which block faulting controlled accommodation development. Active tectonic setting of the basin is responsible for textural properties of the petrofacies. Composition of the petrofacies and its variation through measured sections was mainly controlled by source rocks characteristics. Diagenetic features of the petrofacies are significant enough to necessitate thorough diagenetic study prior to and depositional and/or provenance investigation.

Carbonate rocks of upper Paleozoic host barite ore deposits in the Central Iran. Main ore mineral is barite that shows crosscut relationships with its host rocks and occurs as veins and veinlets. Barite is associated with gold-bearing chalcopyrite. Faulting, fracturing and brecciation were important ground preparation processes in the host rock. Jasperoidization of the host rock prior to barite deposition is another ground preparing process. Open space structures had been filled by ore minerals, hydrothermal calcite and white sparry dolomite. Boiling episodes in the ore-bearing fluids, upon their arrival to the low-pressure dilation zones, along with influx of highly oxidized groundwater provided ideal conditions for ore mineralization. The studied ore deposit could be classified as epithermal based on its temperature of formation (167±11?C), shallow depth, open-space filling structures, mineral assemblages, and jasperoid alterations. Secondary alterations in the primary sulfide minerals had been induced by galvanic reactions, which resulted in formation of various secondary ore minerals. Mineralization in the studied area is in association with the magmatic activities of the early Kimmerian orogeny.

Paleozoic sediments of a section in south of Central Alborz Mountains near the village of Aru were studied in order to determine faunal assemblages, their precise ages and the history of the basin. A sum of 120 samples was collected from four different formations of Jeirud, Mobarak, Doroud and Ruteh. A total of 150 thin sections were prepared and analyzed. Fifty species of Foraminifera were identified and classified in 38 genera. From the biostratigraphic and lithostratigraphic evidence presented here it is clear that excep for the upper contact of the Jeirud Formation, the upper and lower contacts of each of the other three formations cropping out in the Aru area are disconformable and, during the Paleozoic, the sedimentary basin underwent a few major and minor transgressive and regressive events. The absence of Middle - Upper Cambrian, Ordovician, Silurian and Lower Devonian sediments is a result of post-orogenic erosional processes of the Caledonian Orogeny, while the absence of Upper Carboniferous sediments was a result of the Hercynian Orogeny.

During precipitation of diagenetic minerals, any change in pore water chemistry may have a significant effect on the structure and composition of cement. Compositional zoning and dissolution phases in siderite cements of the Early Permian Tirrawarra Sandstone, Cooper Basin, South Australia have recorded pore water chemistry changes induced by tectonically active and passive conditions. Back-scattered electron images of siderite cement reveal three stages of siderite cement as the early (S1), middle (S2), and late (S3) stages. S1 is a structureless iron-rich siderite and S3 is a relatively homogenous cement without extensive compositional zoning, whereas S2 exhibits a rapid compositional zoning associated with several minor dissolution phases. Temperatures of formation of siderite cements indicate that the formation of S1 and S3 has been during passive conditions in the Cooper Basin, whereas S2 formed during active tectonism. The use of compositional zoning of siderite cements may help to identify tectonic conditions during precipitation of cement in other basins.

An inferential Bayesian framework for sample size determination for a clinical trial is presented. It is assumed that the data are from a normal distribution for which the variance is known. We shall apply a Bayesian argument to show how we may use the prior information on the two treatment effects to decide how many patients are needed in each of these two groups.