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141.
Anna Vizi-Orosz Vilmos Galamb Irma Ötvös Gyula Pályi László Markó 《Transition Metal Chemistry》1979,4(5):294-297
Summary The n-donor character of the AsCo3(CO)9 cluster has been tested by reacting it with soft (metal carbonyls) and hard (AlCl3) Lewis acids. The (CO)xMAsCo3(CO)9 compounds (with M=Cr, Mo or W, x=5; M=Fe, x=4) and Cl3Al AsCo3(CO)9 have been prepared. 相似文献
142.
Irma L. Botto Prof. Dr. Enrique J. Baran Pedro J. Aymonino José C. Pedregosa Gabino F. Puelles 《Monatshefte für Chemie / Chemical Monthly》1975,106(6):1559-1566
Mn2As2O7 has been obtained by solid state reaction between As2O5 and MnCO3 at 600 °C and also by thermal decomposition of NH4MnAsO4·H2O. The crystallographic study has shown that the substance crystallizes in the monoclinic thortveitite structure. Its i.r. spectrum was recorded and discussed in relation with their structural properties. The i.r. spectrum of the parent compound NH4MnAsO4·H2O was also briefly discussed.
Mit 1 Abbildung 相似文献
Mit 1 Abbildung 相似文献
143.
Renato Sariego Irma Carkovic Manuel Martínez Mauricio Valderrama 《Transition Metal Chemistry》1984,9(3):106-108
Summary Hydrogen transfer reactions from 2-propanol to acetophenone or cyclohexene are catalyzed by neutral rhodium(I) complexes of the type [Rh(COD)L] and [Rh2(COD)2L] (where L and L are Schiff base ligands and COD=cycloocta-1,5-diene). Some dependency of the catalytic activity on the electronic and steric properties of the ligands are discussed. 相似文献
144.
The accreditation of laboratories has emphasized the use of interlaboratory comparisons as a tool to monitor the comparability
and accuracy of results laboratories produce. An interlaboratory comparison for water laboratories was organized among European
Cooperation for Accreditation (EA) member countries; 30 laboratories, 7 of which were not accredited, from 14 European countries
participated in this intercomparison. All the laboratories were chosen by the appropriate national accreditation bodies, with
the instruction to select as participants those laboratories which act as national reference laboratories in this field. About
90% of the data collected was considered satisfactory after statistical treatment. Non-accredited laboratories performed as
well as accredited laboratories. The laboratories were asked to take corrective action and report the corrections to the accreditation
bodies. A great variation in the reported uncertainties of the results was observed. There seems to be a need to organize
EA interlaboratory comparisons for national reference laboratories analysing water. It is obvious that even reference laboratories need training in how to estimate the uncertainty of results.
Received: 22 July 1998 · Accepted: 21 September 1998 相似文献
145.
PHOTOTOXICITY INDUCED BY HEMATOPORPHYRIN DERIVATIVE IN C5-DEFICIENT, MAST CELL-DEFICIENT AND LEUKOPENIC MICE 总被引:1,自引:0,他引:1
Abstract— The phototoxic response induced by hematoporphyrin derivative and irradiation was evaluated in mice congenitally deficient in the fifth component of complement (C5), those congenitally deficient in mast cells, and in cyclophosphamide-treated, leukopenic mice. Hematoporphyrin derivative, 10 mg/kg, was injected intraperitoneally, and 6 h later, the animals were irradiated (6.5 kj/m2 at396–407 nm). Phototoxicity was quantified by measurement of the increase in ear-thickness. In control mice, at the end of the irradiation (0 h), an increase in the ear-thickness of28–37% was noted; it reached a peak of51–81 % at 24 h. The phototoxic response in C5-deficient mice was markedly suppressed both at 0 h and at 24 h ( P vs control, < 0.02 and < 0.05, respectively), while mast cell-deficient mice has a suppressed response at 24 h ( P vs control, < 0.001). In both groups of mice, the intensity of dermal mononuclear and polymorphonuclear infiltrates was not different from that of the respective controls. The response in leukopenic mice was suppressed at both 24 h and 48 h ( P < 0.001). These results indicate that intimate and complex interactions among the complement system, mast cells, and leukocytes are necessary for the complete manifestation of the phototoxic response. 相似文献
146.
PUVA Treatment Selectively Induces a Cell Cycle Block and Subsequent Apoptosis in Human T-Lymphocytes 总被引:1,自引:0,他引:1
Ray Johnson Lisa Staiano-Coico Lisa Austin Irma Cardinale Reiko Nabeya-Tsukifuji James G. Krueger 《Photochemistry and photobiology》1996,63(5):566-571
Psoralen plus UVA (320–400 nm radiation; PUVA) is a highly effective therapy for cutaneous diseases caused by skin infiltration with normal or neoplastic T-lympho-cytes. In comparing the effects of pharmacologically relevant, low-dose PUVA treatment on growth of human keratinocytes, peripheral blood leukocytes (PBMC), and T-lymphocyte cell lines, we determined that PBMC or T-lymphocytes were >50-fold more sensitive to cytotoxic effects of PUVA, while antiproliferative effects were produced by similar PUVA levels in all cell types. Low doses of PUVA (10 ng/mL 8-methoxypsoralen and 1–2 J/cm2 ) were highly cytotoxic for phytohemagglutinin-activated normal lymphocytes or transformed T-lymphocytes as assessed by two viability assays and by flow cytofluo-rometry. Altered lymphocyte morphology, nuclear fragmentation, TUNEL+ nuclei or nuclear fragments, and the appearance of a sub-G, DNA peak indicated that cell death occurred by apoptosis, beginning about 1 day after PUVA treatment and continuing for several days thereafter. From assessment of cell cycle progression in mi-mosine-synchronized cells, PUVA treatment markedly slowed cell cycle progression, eventually producing cell cycle arrest and apoptotic entry. We propose that the probable basis for disease remissions (psoriasis, cutaneous T-cell lymphoma) produced by PUVA treatment is through selective cytotoxic effects on clonal T-lymphocyte populations that are concentrated in diseased skin. 相似文献
147.
Mellace MG Fagalde F Katz NE Crivelli IG Delgadillo A Leiva AM Loeb B Garland MT Baggio R 《Inorganic chemistry》2004,43(3):1100-1107
New dinuclear asymmetric ruthenium complexes of the type [(bpy)(2)Ru(5-CNphen)Ru(NH(3))(5)](4+/5+) (bpy = 2,2'-bipyridine; 5-CNphen = 5-cyano-1,10-phenanthroline) have been synthesized and characterized by spectroscopic, electrochemical, and photophysical techniques. The structure of the cation [(bpy)(2)Ru(5-CNphen)Ru(NH(3))(5)](4+) has been determined by X-ray diffraction. The mononuclear precursor [Ru(bpy)(2)(5-CNphen)](2+) has also been prepared and studied; while its properties as a photosensitizer are similar to those of [Ru(bpy)(3)](2+), its luminescence at room temperature is quenched by a factor of 5 in the mixed-valent species [(bpy)(2)Ru(II)(5-CNphen)Ru(III)(NH(3))(5)](5+), pointing to the occurrence of intramolecular electron-transfer processes that follow light excitation. From spectral data for the metal-to-metal charge-transfer transition Ru(II) --> Ru(III) in this latter complex, a slight electronic interaction (H(AB) = 190 cm(-1)) is disclosed between both metallic centers through the bridging 5-CNphen. 相似文献
148.
Jadwiga Frelek Irma Panfil Przemyslaw Gluzinski Marek Chmielewski 《Tetrahedron: Asymmetry》1996,7(12):3415-3426
Several isoxazolidin-5-ones were synthesized in an addition — rearrangement reaction from corresponding sugar lactones and hydroxylamines. The sign of the Cotton effect at ca. 220 nm can be correlated to the absolute configuration of the stereogenic center at C3 and can be predicted by Weigang's sector rule. X-ray diffraction study performed for 11 and 12 confirms the configuration at C3 to be 3S and 3R, respectively. 相似文献
149.
The method based on the confidence limits of a regression straight line is applied to the linear portion of the calibration curve of a biosensor in order to determine the limit of detection. A practical application gives a detection limit of an ethanol biosensor greater than that calculated by using the method of the signal‐to‐noise‐ratio, S/N=3, but the value is more reliable because it accounts for the variability in the response at analyte additions. A simple approximation of the method is also presented. 相似文献
150.
Hernn E. Ríos Gerardo A. Ternero Raúl G. Barraza Irma C. Gamboa 《Journal of Polymer Science.Polymer Physics》1994,32(2):215-222
A method which allows the evaluation of phenomenological ion exchange constants Kex is proposed and tested in a cationic polyelectrolyte system. Results for nitrate/chloride exchange are nearly constant over the entire concentration range studied. However, for nitrate/bromide exchange, the results depend on the polyelectrolyte concentration, with Kex following the same trend as the mean activity coefficient for the polyion bromide. For polyion fluoride, a conformational change is probably induced as nitrate is added to the solution and the result deviates from the linear relationship predicted by the method. Benzene sulfonate behaves like a hydrophilic anion, whereas tosylate and ethylbenzene sulfonate also induce conformational changes by hydrophobic interactions. These results are supported by viscosity measurements and agree well with those recently reported by Satoh, who considered changes in apparent molar volume. © 1994 John Wiley & Sons, Inc. 相似文献