Wiedemannic acids

Measurements in this held have been made by Berthelot and Ogier with nitrogen tetroxide Ann. de Chim. et Phys., [v.], 30, 382 (1883)), and with acetic acid ibid., 400), and some calculations with reference to steam have been made by Nernst Verhandl. Deutsch. Phys. Ges., 15, 313) and Levy ibid., 330), who utilised the vapour-pressure measurements of Holborn and Henning Ann. der Physik, (1906), 21 (1907), 22, 23). Wiedemann had previously observed that the specific heats of ethylbromide, ethyl-acetate, and benzene increase with temperature at about the same rate as that of nitrogen tetroxide at 200°. In the case of steam it was assumed that (i.) the polymerisation is to double molecules... 

W. Bettray, J. Schankat, J. Wiedemann, in Enantioselective Synthesis of -Amino Acids (Ed. E. Juaristi), Wiley-VCH, New York 1997, p. 187. 

Wiedemann, H.G. (1971) Applications of thermogravimetry of vapor pressure determination. Thermochim. Acta 3, 355-366. Whitehead, K.E., Geankoplis, C.J. (1955) Separation of formic and sulfuric acids by extraction. Ind. Eng. Chem. 47, 2114-2122. Windholz, M., Editor (1983) The Merck Index. 10th ed., Merck Co., Rahway, NJ. 

A tem containing calcium carbonate, lime, and carbonic acid gas consists of two independent components (o 2) divided into three phases =S) it is a monovariant i stem at a givax temperature the i stem is in equilibrium for a definite value of the pressure, called Ihe dissociation tension of calcium carbonate at the given temperature this tension depends exclusively upon the temperature it depends in no wise upon the masses of the independent components, lime, and carbonic anhydride, which make up the intern this is the celebrated law predicted by Henri Sainte-Claire Deville, demonstrated by Debray for the case that we have just taken as example, and confirmed by Debray and by G. Wiedemann vdien studying the dissociation of hydrated salts, and by Isambert from a study of the dissociation of compounds that ammonia gas forms with certain metallic chlorides. 

The class A P-lactamases are a subset of the active-site serine P-lactamases. TEM-1 P-lactamase is a class A enzyme encoded by the ft/ajEM-l gene that is present on the transposons Tn2 and Tn3 (Datta et al, 1965). Epidemiological studies have shown that TEM-1 is the most common plasmid-mediated P-lactamase and is therefore a major determinant of bacterial resistance to P-lactam antibiotics (Wiedemann et al, 1989). Compounding the problem of resistance is the discovery that TEM-1 mutant variants with altered substrate specificity have been identified in natural isolates (Jacoby and Medieros, 1991). These variant enzymes contain from one to three amino acid substitutions that enable the enzyme to hydrolyze the newer extended-spectrum cephalosporin antibiotics such as cefotaxime and ceftazidime (Jacoby and Medieros, 1991). Thus, the selective pressure of antibiotic therapy le s to die creation of new enzymes with expanded hydrolytic capabilities. 

Enders, D., Bettray, W., Schankat, J., Wiedemann, J. Diastereo- and enantioselective synthesis of P-amino acids via SAMP hydrazones and hetero Michael addition using TMS-SAMP as a chiral equivalent of ammonia. Enantioselective Synthesis of/T-Amino Acids 1997,187-210. 

The determination of the vapor pressure of various compounds was reviewed by Wiedemann (49). He discussed the determination of vapor pressure by TG techniques based on the Knudsen effusion method. The sample holder that was employed is illustrated in Chapter 3 (Figure 3.6). For some measurements, a Pyrex glass cell having a diameter of about 15 mm was used. Four organic compounds were studied p-chlorophenyl-AT. Af-dimethyl urea (Monuron. a herbicide), p-phenacetin, anthracene, and benzoic acid, in the temperature range of 250-400 K. The vapor-pressure curves of these compounds, in the range from 0 10 Torr, are shown in Figure 4.49. The AHs values calculated were Monuron. 27.4 p-phenacetin 27.6 anthracene, 20.1 and benzoic acid. 20.7 kcalmole. 

Pancreaticoblastoma, or infantile adenocarcinoma, is a rare tumor in children (Monte marano et al. 2000 Roebuck et al. 2001). It usually presents in the fourth year of life with males being more affected than females. This tumor conunonly arises from the head or tail of the gland, and has been associated with Beckwith-Wiedemann syndrome. Microscopic analysis will show proliferation of poor differentiated squamous cells surrounded by a fibrous capsule. Although it has a better prognosis than the adult adenocarcinoma, metastases can occur and are commonly present at the time of the initial exam or diagnosis. Common sites for metastases include the liver and lymph nodes. Lung and brain metastasis are rarely seen. Usually, vanillylmandelic acids (VMA) are not elevated but the alpha-fetoprotein is. 

A Schultz, K Wiedemann, I Bitsch. Stabilization of 5-methyltetrahydrofolic acid and subsequent analysis by reversed-phase high-performance liquid chromatography. J Chromatogi 328 417-421, 1985. 

Barium copper siUcate purple was found to be thermally unstable, and this phenomenon Wiedemann et al. (1998) have linked to the crystal structure. The colour is also known to fade dramatically when exposed to acid (Wiedemann and Bayer, 1997 FitzHugh and Zycherman, 1992). 

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