Selective permeation of o-, m-, and p-isomers of benzene derivatives through polymer membranes based on cyclodextrin complexation in the bulk aqueous solution

Transport behavior of several aromatic compounds through a poly(vinyl chloride)membrane and poly(vinyl alcohol)-poly(ethylenimine) composite membranes was studied in the presence of cyclodextrin in the aqueous solution. o-Isomers of nitrophenol, nitroaniline, and iodophenol were effectively separated from their mixture of regio isomers based on the preferential complexation between cyclodextrin and the m- and p-isomers over the o-isomers. Pumping of p-nitroaniline across the membrane was also observed by addition of cyclodextrin. The results were explained as a consequence of the selective complex formation between cyclodexarin and substrate and the low membrane permeability of the complexes.     

Abscesses caused by "dropped" stones after laparoscopic cholecystectomy for cholelithiasis: a report of three cases

This presentation gives an overview about the factors involved in the regulation of gluconeogenesis. Then, based on these regulatory principles, the changes seen in impaired liver function are discussed. Gluconeogenesis from lactate and pyruvate is mediated through pyruvate carboxylase (PC) and phosphoenolpyruvate carboxykinase (PEPCK) activity. The PC mediated pathway depends on substrate supply and on the downregulation of the oxidative pathway for pyruvate. Both enzymes need ATP or GTP and, thus, depend on the cellular energy charge. Tissue anoxia can reduce the energy charge and limit the flow through the PEPCK pathway. Thus, one expects a coupling between reduced splanchnic blood flow, limited oxygen supply to the liver, resulting tissue anoxia, and reduced gluconeogenesis. Conditions are shown, where this coupling exists. Since gluconeogenesis is concentrated in the periportal region of the liver, the local oxygen tension is sufficient under many circumstances to maintain a high glucose production level. Also, the enzyme activity of PEPCK can compensate for long term anoxia. Thus, gluconeogenesis is sufficient in most cases, as seen in critically ill patients. However, this could be associated with a reduction in the perivenous oxygen tension, possibly below critical levels. Beta-adrenergic stimulation increases gluconeogenesis. Examples are shown where this stimulation can overlay the dependency on the oxygen tension and substrate supply. Catecholamines are generally used to stabilize the hemodynamic system. This treatment could limit splanchnic bloodflow and, as a consequence, the oxygen supply to the liver with a simultaneous stimulation of gluconeogenesis and can cause severe anoxia in the perivenous region. These negative side effects of catecholamine treatment should be avoided and the ideal treatment should aim at improving splanchnic flow without stimulation of gluconeogenesis.     

Thermal conductivity study of thin He films adsorbed in porous glasses with well controlled pore sizes

Thermal conductivity study of thin He films adsorbed in porous glasses with well controlled pore sizes^[2] is reported. The measurements are performed in a cell where a torsional oscillator monitors the superfluid density change, for the same films for comparison. Since the heat flux through the superfluid is proportional to the superfluid velocity, we discuss the possible observation of the intrinsic critical velocity v_sl = h/ml, inherent in superfluid He films in such porous systems with unit pore length l, as discussed by Minoguchi and Nagaoka^[3], which marks the velocity at which phase slippages start to occur over macroscopic scales.on leave from: Inst. Physics near Prahaon leave from: Lukin's Research Inst. Phys. Problems, Zelnograd, Moscow.     

Anti-idiotype monoclonal antibodies against anti-microcystin antibody and their use in enzyme immunoassay

Two different makes of bioimpedance spectrometer (UniQuest-SEAC SFB-3 and Xitron 4000B) were used for a series of measurements on volunteers and patients in intensive care. Although each machine was accurate over the frequency range 5 to 500 kHz when bench tested on model resistor-capacitor circuits, significant differences in their recorded impedance parameters appeared when used in vivo, especially on intensive care patients. A series of laboratory tests was performed on each machine simulating the situation in vivo to identify possible reasons for these differences. Whilst stray capacitance in the environment was identified as the major contributor to variability in high-frequency performance, interaction between electrode impedance and lead positioning was also a factor. The observed phase shift with frequency or time delay (Td) used in the Xitron modeling software appears to be the result of a time constant caused by stray capacitance and so is unlikely to have any biological meaning. Significant differences in the in vivo numerical values produced by bioimpedance spectrometers may be attributed to instrument design, data processing and, in particular, the clinical environment.     

Epidemiologic study on physical conditions related to work among the elderly]

The present study was conducted in order to examine the epidemiologic factors related to work capacity among the elderly. As study area, Ogimi Village in Okinawa Prefecture was selected by reason of the long life expectancy of the inhabitants. Medical examination and interview were conducted on 756 inhabitants aged 65 yr and older. Working status was classified into two groups, that is, working group and non-working group. The association between working status and related factors was examined by using multiple logistic regression analysis. The examined factors were as follows: sex, age, history of apoplexy, history of being down, history of falls, history of fracture, chewing ability, pain, exercise habit, hobby, education, number of family members, alcohol, smoking, food intake frequencies and medical indicators (blood pressure, ECG, Quetlet index, skinfold thickness, grip strength, one-leg test with eyes opened, albumin, total cholesterol, hemoglobin and HDL-cholesterol). The results of the analysis revealed that grip strength and one-leg test with eyes opened had a statistically significant correlation with working status (p < 0.01). From the results, maintenance of muscle strength and equilibrium function were found to be the physical conditions related to work among the elderly in the agricultural area.     

Effects of Mn,P, and mo on sulfide stress cracking resistance of high strength low alloy steels

Effects of phosphorus, manganese, and molybdenum on sulfide stress cracking (SSC) resistance were investigated by the constant load SSC test for low alloy steels with tempered martensite struc-ture and yield strength of 690 MPa to 820 MPa. The SSC threshold stress begins to decrease with an increase in yield strength at a certain yield strength (an SSC critical strength). The fraction of inter-granular fracture surface begins to increase with an increase in yield strength at the SSC critical strength, while the fracture mode becomes transgranular below this strength. Furthermore, there ex-ists a relationship between an increase in the fraction of intergranular fracture surface and a decrease in the SSC threshold stress. A decrease in phosphorus and manganese content and an increase in molybdenum content make the SSC critical strength higher. These changes in content of chemical elements, therefore, lead to an increase in the SSC threshold stress due to a decrease in the amount of intergranular fracture surface above the SSC critical strength. Below the SSC critical strength, however, the change of the SSC threshold stress is not observed because the fracture mode remains fully transgranular. The SSC critical strength could be represented as a function of a parameter com-posed of manganese and phosphorus contents.     

Role of Phe120 in the activity and structure of bovine pancreatic ribonuclease A

A method was evaluated to control for off-resonance saturation in noninvasive magnetic resonance imaging with continuous arterial spin labeling of cerebral blood flow. In phantoms and humans, application of amplitude-modulated radio-frequency irradiation during the control image corrected for saturation across the whole brain and made possible cerebral blood flow imaging in multiple sections at arbitrary angles to the labeling plane.