Imipramine distribution among red blood cells, plasma and brain tissue

Hypertension complicates the treatment of anaemia of chronic renal failure with recombinant human erythropoietin (EPO) in some patients. We conducted a prospective study measuring changes in cardiac index (CI) and systemic vascular resistance index (SVRI) in 29 patients from before commencement of EPO to attainment of target haemoglobin concentration. We used the operator-independent technique of trans-thoracic bioimpedance. The group of patients who developed EPO-induced hypertension (EpHT) were separately analysed and compared with the group who had no change in blood pressure (NC). Our results showed there was a significant rise in SVRI after treatment in EpHT group patients but in the NC group there was a small fall. CI increased significantly in the NC group after treatment but no change was recorded in the EpHT group. These findings clearly demonstrate how the cardiovascular changes differ in patients who develop EPO-induced hypertension.     

Comparison of Pyrometric Co-C and Re-C Eutectic-Point Cells Between VNIIM and LNE-Cnam

VNIIM and LNE-Cnam have collaborated for several years in the field of metal-carbon eutectic points. The first action was the construction of a Pt-C cell at VNIIM using the LNE-Cnam technique and cell design. The Pt-C cells constructed in each of the laboratories were studied and compared in the past. The two laboratories have followed their collaboration work by studying and comparing Co-C and Re-C cells. Different designs and filling techniques were applied. The melting and freezing temperatures observed on the Re-C cells from the two laboratories were measured at VNIIM. The Re-C and Co-C cells were compared at LNE-Cnam in the high-temperature blackbody furnace HTBB 3200pg which was thermally optimized before the measurements. The results of the comparison showed that the Co-C cells were comparable at the level of 0.03 K while the Re-C cells showed a large difference of melting temperatures of about 0.7 K. In this article, the cells used and the methodology of the comparison will be described. The temperature differences that were obtained at the highest temperature will be examined to propose an explanation for this temperature difference.     

Correlation Between Immersion Profile and Measured Value of Fixed-Point Temperature

Assessment of thermal immersion effects in the melting and freezing points defined by the International Temperature Scale of 1990 is one of the vital issues of modern thermometry. In documents of the Consultative Committee for Thermometry, the deviation of the experimental immersion profile from the theoretical value of the hydrostatic effect at a height of about 3 cm to 5 cm from the thermometer well bottom is used for the estimation of the uncertainty due to unwanted thermal effects. This estimation assumes the occurrence of solely the hydrostatic effect all along the height of the well inner wall. Real distortions of the temperature gradient at the bottom and at the top part of the well caused by the change of heat-exchange conditions are not taken into account. To define more precisely the temperature gradient along the height of the well, a miniature PRT with a 30 mm sensitive element and a sheath length and diameter of about 60 mm and 6 mm, respectively, were used. Also, the measurements of fixed-points temperature at noticeably different slopes of immersion profiles due to variations of the thermometer heat exchange and phase transition realization conditions were produced by means of a standard platinum resistance thermometer (SPRT). The measurements were carried out at the tin and zinc freezing points. The immersion curves measured with a miniature thermometer demonstrated an increase of the temperature during its lifting in the first 1 cm to 3 cm above the bottom of the well. The measurement results at the zinc freezing point by means of the SPRT have not confirmed the correlation between the immersion curves, the received value of the Zn freezing temperature, and the estimation of its uncertainty.     

Methods for the Realization of its-90 Fixed Points: Necessity of Improvement

Measurement Techniques - We consider the problems of consistency of the results of international comparisons, equivalence of the national standards, and improvement of the methods aimed at the...     

Evolution of the Inner Liquid–Solid Interface During Metal Freezing

The influence of the inner interface initiation method on the interface shape (formation of the planar interface or the interface with the dendrites growing into the liquid metal) was studied both theoretically and experimentally. The results of numerical simulation of the process of heat removal from the metal, corresponding to different initiation methods, revealed the existence of different species of the inner interface. The interface modification during freezing arises from the inequality of temperature gradients on opposite sides of the interface, i.e., from imbalance of heat fluxes on the interphase boundary (Stefan problem). For indium point, the results of numerical simulation were confirmed experimentally.     

State Primary Standard of Temperature Unit in the Range 0–3200°C GET 34-2020: Practical Implementation of the New Definition of Kelvin

Measurement Techniques - We consider the necessity and means of modernizing the State primary standard GET 34-2007 of the unit of temperature in the range of 0–3000°С. The problem...     

Experimental and Numerical Investigation of the Temperature Field of a Fixed-Point Cavity

The temperature field non-uniformity of a blackbody cavity is one of the components of uncertainty of fixed-point realization. Here a study of the design and opportunities of the temperature furnace used in VNIIM is described. The dependence of the uniformity of a temperature field on various factors is shown by results of numerical calculations of a temperature field of VNIIM??s copper and gold fixed-point cells, realized with the software packages Elcut 5.3 and Ansys 11.0. A thermophysical model of the phase transition considered as steady state with convection and radiation heat exchange to an environment is applied. The basic focus is made on calculation of the radiation heat exchange between crucible elements and the environment and a furnace cavity, as a dominating component of the heat transfer. Results using analytically and numerically calculated angular factors of radiation of heat exchange are discussed. The data obtained in measurements of a temperature field of a cavity fixed point during phase transitions of copper and gold by a spectrocomparator with high sensitivity, are also shown here. Both theoretical calculation and experiment were realized at various distributions of temperature along an external surface of a crucible. Good agreement of results between steady-state calculation of a temperature field and the measured data with the best entry conditions is observed. The average value of non-uniformity of a temperature field along a cavity for points of phase transition of copper and gold for an 88?mm long graphite crucible with a 54?mm deep, 8?mm diameter cavity was 40?mK, and the temperature drop across the graphite wall was 20 mK. In this paper the reasons for occurrence of large gradients inside a fixed-point cavity during the phase transition, received during some experimental research, are also discussed.     

Regioselective Alcoholysis of Silychristin Acetates Catalyzed by Lipases

A panel of lipases was screened for the selective acetylation and alcoholysis of silychristin and silychristin peracetate, respectively. Acetylation at primary alcoholic group (C-22) of silychristin was accomplished by lipase PS (Pseudomonas cepacia) immobilized on diatomite using vinyl acetate as an acetyl donor, whereas selective deacetylation of 22-O-acetyl silychristin was accomplished by Novozym 435 in methyl tert-butyl ether/n-butanol. Both of these reactions occurred without diastereomeric discrimination of silychristin A and B. Both of these enzymes were found to be capable to regioselective deacetylation of hexaacetyl silychristin to afford penta-, tetra- and tri-acetyl derivatives, which could be obtained as pure synthons for further selective modifications of the parent molecule.