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81.
In July 1997 Professor Harry Rilbe passed away at the age of 84. Harry Rilbe was an outstanding personality skilled in chemistry, optics and mathematics, and he will be remembered for his important contributions to the development of separation methods, notably moving boundary electrophoresis and isoelectric focusing. The latter method is used for analytical and preparative purposes in thousands of laboratories worldwide. Isoelectric focusing is indispensable for characterization of proteins from humans, animals, plants and microorganisms. Isoelectric focusing is thus useful for the understanding of the function of genes and, accordingly, for progress in the life sciences. A biographical retrospect, "A scientific life with chemistry, optics and mathematics", was published by Harry Rilbe in Electrophoresis 1984, 5, 1-17. 相似文献
82.
Raman scattering from the transverse optical phonon in the hcp phase of solid H2 and D2 has been observed as a function of the density of the solid. Frequencies have been measured, with an accuracy of 0.3 cm–1, in crystals under pressures up to 5000 bar at the melting line. A linear dependence of ln TO on ln V is found (TO is the phonon frequency and V the molar volume) with mode Grüneisen constants of TO = 2.07 ± 0.03 for H2 and TO = 1.95 ± 0.03 for D2. The ratio of the phonon frequencies of H2 and D2 at the same molar volume varies between 1.38 and 1.41 over the whole density range, in contrast to the harmonic ratio of 2 obtained from the mass ratio of 2 between H2 and D2. The results are compared with calculations of the phonon frequencies. A fit is provided so that phonon frequencies can be used as a pressure or density calibration scale.Supported financially by the Stichting FOM. 相似文献
83.
R. Jochemsen V. V. Goldman Isaac F. Silvera 《Journal of Low Temperature Physics》1979,36(3-4):243-278
We present an experimental study of the infrared absorption spectra of solid enriched ortho-hydrogen and para-deuterium in the ordered state for pressures up to 6 kbar. From our observations we can conclude that the structure of the ordered state remains the Pa3 space group for all pressures studied. We find that the low-frequency optical phonon remains sharp at increased density and we have determined the mode Grüneisen constants as H
2=1.95±0.03 and D
2=1.87±0.03. The high-frequency optical phonon remains broad, and develops a double-peaked structure with increasing density, which is explained by anharmonicity and two-phonon decay. Comparison is made to theoretical expressions and numerical results for the absorption due to various microscopic processes involving phonons and combinations of librons and phonons. The integrated absorption intensity is also obtained, and compared with calculations based upon the quadrupole-induced dipole mechanism.Financially supported in part by the Stichting FOM, Utrecht. 相似文献
84.
Piet J. Berkhout J. Th. Minneboo Isaac F. Silvera 《Journal of Low Temperature Physics》1978,32(3-4):401-417
A study of the Raman scattering spectra of orientationally ordered ortho-H2 and para -D2 as a function of J = 0 impurities is presented. Libron peak frequencies over the concentration region 0.75 <c
1< 0.98 are determined and show a linear concentration dependence that can be represented by the relation (1)[1 – K(1 – c1)]. A least squares fit of our data gives values of K = 1.27 ± 0.05, 1.28 ± 0.05, and 0.96 ± 0.05 in D2 where = E
g, T
g
(1)
, and T
g
(2)
, respectively, and K 1.32 ± 0.05 and 0.97 ± 0.05 for the E
g and T
g
(2)
modes in H2. Results are compared to the values calculated by Diehl et al. using the coherent potential approximation for the J = 0 impurity problem. Extrapolated values for (1) were obtained that are slightly higher than those given by Hardy, Silvera, and McTague, resulting in an increased value for the effective interaction parameter eff. Conversion rates for H2 and D2 are determined, resulting in k
H2 = 0.0193 ± 0.0007h–1 and k
D2 = 0.00063 ± 0.0001 h–1.Supported by the Stichting voor Fundamenteel Onderzoek der Materie (FOM). 相似文献
85.
Experiments on rabbits demonstrated phasic changes in the nervous system excitability in aseptic inflammation against the background of latent tetanus intoxication (according to the results of investigation of the neuro-muscular chronaxia and the entire electroexcitability curve ("power-duration"). Apparently this is of definite significance in the changes of interrelations between the reactivity and the resistance of the organism and in the action on the phlogogenic agent. 相似文献
86.
MT Wu IF Mao CK Ho D Wypij PL Lu TJ Smith ML Chen DC Christiani 《Canadian Metallurgical Quarterly》1998,55(7):461-467
We analyzed the long-term results and the quality of life in patients who received orthotopic lower urinary tract reconstruction using the Kock ileal neobladder. Between July 1990 and October 1993, 37 consecutive patients including 2 females received orthotopic hemi-Kock neobladder after radical cystectomy. In these patients, we analyzed the urinary continence, complications and urethral recurrence, and performed a questionnaire survey by mail. Good continence all day had been achieved in 71% of the patients 4 years after surgery. The rate of the pouch-related complications requiring reoperation was 27%. There was no urethral recurrence. Compared with preoperative conditions, 42% were not satisfied with urination. In these dissatisfied patients, the need to use pads in the daytime, sensation of residual urine and weak urine stream were significantly more frequent than in satisfied patients. In summary, the rate of complications was higher than that of other methods. However, the Kock orthotopic ileal neobladder is a stable procedure providing good function over the long-term. 相似文献
87.
The extracellular pH (pHe) in solid tumours is frequently lower than the pHe in normal tissues. Cells within an acidic environment depend on mechanisms which regulate intracellular pH (pHi) for their survival, including the Na+/H+ antiport which exports protons in exchange for Na+ ions. Amiloride and its analogues DMA (5-(N,N-dimethyl)amiloride), MIBA (5-(N-methyl-N-isobutyl)amiloride) and EIPA (5-(N-ethyl-N-isopropyl)amiloride) are known to inhibit the Na+/H+ antiport and therefore decrease the cells ability to regulate pHi. All three analogues were found to be potent inhibitors of the antiport in human MGH-U1 and murine EMT-6 cells, with DMA being approximately 20, MIBA 100 and EIPA 200-fold as potent as amiloride; EIPA also gave more complete suppression of the Na+/H+ antiport. These agents were not toxic to cells when used alone; however, in combination with nigericin, an agent which acidifies cells, all three analogues were toxic to cells at pHe < 7.0, and markedly enhanced the toxicity of nigericin alone. Cell killing was greatest for nigericin used with EIPA or MIBA. None of the agents were toxic to cells at pHe 7.0 or above. When used against variant cells lacking the Na+/H+ antiport (PS-120 cells) EIPA did not enhance the cytotoxicity of nigericin alone, suggesting that the observed effect was due to inhibition of Na+/H+ exchange, rather than due to non-specific effects. The combination of EIPA and nigericin gave similar cell killing in previously dissociated and intact MGH-U1 spheroids, suggesting that the agents have good penetration of solid tissue. Preliminary experiments using EMT-6 tumours in mice suggested that EIPA and nigericin were able to enhance the toxicity of radiation in vivo, presumably through selective effects against the hypoxic (and probably acidic) subpopulation of cells that is resistant to radiation. 相似文献
88.
89.
Observation of female health in a region having higher background radiation suggests that Chernobyl plant accident has not induced symptomatic radiation disorders, but actually altered immune system. Chances are that long-term consequences of exposure to radiation will induce higher incidence of immune-related diseases. Females residents of Moscow suburb demonstrated more favorable results of immunologic study, than those of regions exposed to radiation. 相似文献
90.