Steric requirements for coal swelling by amine bases

A set of six coals ranging in rank from lignite to hvA bituminous was swollen with a series of alkyl-substituted pyridines and a smaller set of 4-alkylanilines. The size and branching of the alkyl groups was varied and the effect of this variation on the dissolution of the amines in the coal and the resulting coal swelling was measured volumetrically. In a few cases, substituents which hindered the amine nitrogen were studied. The lignite and subbituminous coal have a much higher tolerance to branched, bulky groups than do the bituminous coals. The presence of tertiary groups in a solute strongly inhibits their dissolution in bituminous coals. Bituminous coals behave as if extensive parallel packing of structures occurs. Often, they can accept very large planar groups but have a low capacity for branched groups.     

Linear crosstalk in 4×4 semiconductor optical amplifier gateswitch matrix

We report a comprehensive crosstalk investigation of a packaged InGaAsP/InP 4×4 semiconductor optical amplifier gate switch matrix, experimentally as well as theoretically. For a fully loaded switch with the same wavelength on all four inputs, all possible switching combinations are analyzed, thus yielding realistic crosstalk figures. Coherent and incoherent crosstalk phenomena are identified, and a switch crosstalk less than -40 dB has been measured     

Role of nitric oxide in the regulation of the hepatic microcirculation in vivo

BACKGROUND/AIMS: Nitric oxide (NO) is an important mediator in the regulation of vascular tone. However, no data exist on the physiological role of NO in the regulation of the hepatic microcirculation. This study was designed to evaluate the role of NO in the hepatic microcirculation in vivo under physiological conditions. METHODS: The hepatic microcirculation was investigated in anesthetized rats by intravital fluorescence microscopy after injection of fluorescein-isothiocyanate-labeled erythrocytes. Following assessment of baseline sinusoidal perfusion, animals were randomly treated with L-NMMA (n=6), L-arginine (n=6), nitroprusside sodium (NPS, n=5) or a comparable volume of NaCl (n=4). Drugs were given through a portal vein catheter at three doses (Dx), each followed by intravital microscopy. L-NMMA was given: 5 mg/kg (D1), 25 mg/kg (D2), 50 mg/kg (D3); L-arginine 30 mg/kg (D1), 150 mg/kg (D2), 300 mg/kg (D3); and NPS continuously 80 microg x kg(-1) x h(-1). RESULTS: L-NMMA induced a significant increase of mean arterial blood pressure (MAP) (114 vs. 129 mm Hg; p<0.05). In contrast, MAP of NPS-treated animals decreased (107 vs. 91 mm Hg; p<0.01) whereas MAP of animals receiving L-arginine did not significantly differ. Sinusoidal blood flow revealed dose-dependent changes: L-NMMA significantly decreased perfusion of sinusoids (D1: 65%, D2: 57%, D3: 50% of baseline, p<0.05). Injection of L-arginine increased the sinusoidal flow even with the lowest dose (D1: 137%, D2: 133%, D3: 123%, p<0.05). Continuous infusion of NPS had little effect on sinusoidal blood flow at the first and second times of microscopy but sinusoidal blood flow was significantly increased at the third time (D1: 103%, D2: 106%, D3: 122%). CONCLUSIONS: Inhibition of NOS results in a dose-dependent disturbance of the hepatic microcirculation despite significantly increased MAP, whereas L-arginine increases the sinusoidal blood flow. The results indicate an important role for NO in the regulatory mechanisms of hepatic sinusoidal perfusion under physiological conditions.     

Reaction time during cocaine versus alcohol withdrawal: longitudinal measures of visual and auditory suppression

Visual and auditory stimulus discrimination tasks, analogous to those used in the Reitan-Klove Sensory Perceptual Examination, were performed by 12 cocaine-dependent and 5 alcohol-dependent patients after 1 week, 3 weeks, and 3 months of verified abstinence. Sixteen control subjects, who were not substance-dependent, performed the same tasks after comparable intervals. During each task, either visual or auditory stimuli were presented in the left, in the right, or in both sensory fields. A simple key press was made to discriminate these conditions. Cocaine-dependent patients responded more slowly than control subjects during both tasks. The reaction-time slowing persisted across all three sessions, spanning a 3-month period of abstinence. There were no significant differences between the cocaine-dependent and control groups in response accuracy. In the context of other findings, these findings are interpreted as reflecting an enduring effect of prior cocaine dependence on motor as opposed to sensory functioning.     

Fertilization in vitro. A review over the medical indications and suggestion to unified guidelines for public fertility clinics in Denmark

Medical indications for in vitro fertilization and embryo transfer (IVF-ET) internationally and in Denmark are reviewed. Reports from large international centres document that tubal infertility, unexplained infertility, endometriosis and male infertility are equally good indications for IVF. Traditionally, tubal infertility has been the only medical indication qualifying for IVF treatment within the National Health Service in Denmark. Thus, in this country, couples with unexplained and male infertility and with endometriosis have to pay up to 25,000 D.Kr. per IVF-ET treatment in private fertility clinics. Since there is no scientific basis for this discrimination, it is urged that the present rules are changed, so that couples with unexplained and male infertility and endometriosis are also allowed IVF treatment free of charge in the public fertility clinics.     

Determination of volterra transfer functions of non-linear multiport networks

A method is presented to determine frequency domain Volterra transfer functions of non-linear multiport networks containing non-linear multiport subsystems (elements). the method is based on an extension of the probing method to allow arbitrary (also commensurate) frequencies. A recursively based algorithm for the determination of Volterra transfer functions of non-linear multiport networks is derived. A computer implementation of the method in a symbolic programming language is presented. This makes it possible to determine algebraic expressions of the Volterra transfer functions. Three examples are considered.     

Changes in the kinetics of the hemoglobin, total protein and DNA content in rat erythroid cells in experimental anemia. I. The peripheral blood

Cytophotometry of rat blood erythroid cells during anaemia, induced by phenylhydrazin (4-8 days from the beginning of injections), revealed that all forms of bone marrow containing haemoglobin were thrown into the blood. On its peak (4th day), the greatest contribution in blood haemoglobinization (50%) is made by microcytes. From the 5th day and up to the end of the restoration period the important role in this process is played by macrocytes. From the 6th day the role of normocytes increases, whose contribution by 8th day reaches 70% of the whole haemoglobin amount in blood. In contrary to anaemizated birds, whose erythroid cells ripen in blood, in rats all the transformations of erythron during anaemia are accomplished in bone marrow.     

High dietary calcium level decreases colonic phytate degradation in pigs fed a rapeseed diet

The degradation of phytate (inositol hexaphosphate) in rapeseed meal diet not containing phytase activity was studied in 15 growing ileum-fistulated pigs. Stomach and small intestinal degradation and total gastrointestinal degradation were compared. The effect of addition of calcium carbonate to the rapeseed meal diet at two levels (9.2 and 18.5 g/kg diet) was investigated. A commercial barley-wheat-soybean diet with intrinsic phytase activity was used as reference. Phytate and its hydrolysis products in diets, ileal digesta and feces were determined by HPLC ion-pair chromatography. Hydrolysis of phytate in the stomach and small intestine was 35-45% in pigs fed the rapeseed meal diet independent of calcium addition, and 65% in pigs fed the reference diet. Total gastrointestinal degradation of phytate in pigs fed the rapeseed diet was 97, 77 and 42% (P < 0.001) when calcium intakes were 4.5, 9.9 and 15 g/d, respectively; total gastrointestinal degradation was 72% in pigs fed the reference diet. The intestinal phytate degradation pattern, when rapeseed diet was fed, indicated the activity of an unspecific phosphatase, whereas that of the reference diet indicated intrinsic dietary phytase activity. We conclude that dietary supplementation of calcium carbonate decreases the phytate degradation in the colon of pigs, but not in the stomach and small intestine.