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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Intensive care medicine 26 (2000), S. S022 
    ISSN: 1432-1238
    Keywords: Key words Nosocomial infection ; Antibiotics ; Environment ; Handwashing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Small intensive care units (ICUs) functioning within their capacity and caring mainly for post-operative patients have fewer problems with infection control than larger ICUs with a varied case mix, sub-optimal staffing levels, and high levels of antibiotic consumption. Under these circumstances chronic cross colonisation and infection are inevitable and outbreaks may occur. Little can be done to reduce the risks of infection which arise as a direct result of the patient's clinical condition and prior colonisation status. However, selection pressure from antibiotic usage can be modified, as can environmental hygiene, ventilation and architectural design. One of the simplest measures for reducing cross infection remains one of the most intractable: compliance by staff with protocols and standards for maintaining hand hygiene. Simplification of procedures by the ready availability of alcohol hand rub preparations with or without chlorhexidine may improve matters.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 29 (1990), S. 393-405 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Tm of internal loop-forming (dA · dT)N domains in pBR322 DNA has been measured over a tenfold range of [Na+]. The slopes SN = dTm/d log[Na+] are linear and decrease in magnitude with decreasing loop size N, signaling a reduction in Na+ released during the transition of these domains to the coil state. Values of SN decrese linearly with increasing N-1 in accordance with the expectation of a simple model for the occurrence of a gradient of long-range electrostatic forces at helix-coil boundaries, and extrapolate almost precisely to the value of S∞ observed for (dA · dT)∞. These results indicate (1) less counterion is released per phosphate residue from the finite loop than from the infinitesized loop, and (2) the difference in binding is constant for each boundary formed and independent of the size of the loop within the range examined: ∼ 350 base pair (bp) 〉 N 〉 71 bp. The slope of the dependence of SN on N-1 indicates the region of higher charge density at the boundary extends at least 18 Å into the coil and probably 40-50 Å before dropping to a value characteristic of the unperturbed coil. The free energy for excess counterion binding at boundaries can be expressed by \documentclass{article}\pagestyle{empty}\begin{document}$$ {{ - \Delta G} \mathord{\left/ {\vphantom {{ - \Delta G} {RT}}} \right. \kern-\nulldelimiterspace} {RT}} = 10.47{\rm log}\left[{{\rm Na}^ + } \right] + 5.234 $$\end{document} When the loop entropy function in a statistical mechanical algorithm for the dissociation of DNA is weighted by this quantity, calculated Tm are seen to vary by only ±0.09°C from observed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 2293-2302 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Several alkoxy/aryloxy-substituted phosphazene polymers [P(OR)2 = N]n, where R = C6H5, CH2CF3, C8H10, were prepared by the reaction of polydichlorophosphazene with their corresponding sodium salts. The polydichlorophosphazene was obtained by the solution polymerization of hexachlorocyclotriphosphazene in 1,2,4-trichlorobenzene. Sulfamic acid and ammonium sulfamate were used as catalysts. Apparently, sulfamic acid functions as a catalyst through its acid group in some decomposed form. New catalysts, p-toluenesulfonic acid and sulfobenzoic aicd, have been developed for this solution polymerization. The polymerization favors a cationic mechanism. A promoter, CaSO4·2H2O, was found to speed up the polymerization reaction. Effect of several parameters such as dilution, catalyst concentration, and promoter concentration on the properties of the final polymer were investigated. The polymers were characterized by differential scanning calorimetry, gel permeation chromatography, and 31P solution NMR spectroscopy.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 789-797 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The antioxidant mechanism of zinc dialkyl dithiocarbamate is examined in detail in model compounds. The kinetics of the reaction of zinc dialkyl dithiocarbamate with hydroperoxides were studied in inert and oxidizable substrates. A typical electron donor antioxidant and a base (CaCO3) were found to inhibit the peroxide decomposition. The oxidation products of the Zinc II complex appear to be quite different from those of the nickel II and iron III complexes. Two processes are involved in the antioxidant function of the zinc complex: The first is a free radical decomposition of the peroxides, which predominates at molar cumene hydroperoxide (CHP)/zinc diethyl dithiocarbamate (ZnDEC) ratios of 10 or less. At higher molar ratios an ionic reaction predominates, although there is a radical contribution at all ratios. Thiocarbamoyl disulfide does not seem to be formed as an intermediate from ZnDEC during the ionic process.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 33 (1987), S. 1455-1471 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The behaviors of iron, nickel, and zinc dialkyl dithiocarbamates were compared with the corresponding thiuram disulphide in their reaction with cumene hydroperoxide (CHP) at 110°C. The metal complexes exhibit both homolytic and heterolytic processes and transformation products formed during the above reactions and not the initial metal complexes were found to be responsible for the heterolytic decomposition process. However, the nature of the initial transformation products in the case of the iron and nickel complexes differed from those of the corresponding zinc complex. In the former case the corresponding disulfide was shown to be the initial transformation product while there was no evidence for the formation of disulfide in the case of the zinc complex. This difference appears to be responsible for the observed different kinetic behavior of CHP decomposition in the presence of the nickel and iron complexes from that in the presence of zinc. This thiuram disulfide behaves quite differently from the metal complexes in that heterolytic decomposition of hydroperoxide predominates at all molar ratios of the disulphide to the CHP. The hydroperoxide decomposition curves in this case show only one step in contrast to the metal complexes which show a multistep behavior, and this was shown to correspond to the third catalytic stage in the reaction of the metal complexes. Comparison of the rate constant of this step with that of the final step of the metal complexes shows a close resemblance to the case of the iron and nickel and is quite different from that of the zinc complex, confirming the intermediacy of the disulfide in the former cases but not in the latter.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 33 (1987), S. 703-713 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of the processing operation on the nature and quantity of transformation products of 2,2,6,6-tetramethyl-4-hydroxypiperidinoxyl (〉NO.) and its corresponding hydroxylamine (〉NOH) was investigated in polypropylene. It was found that both 〉NO. and 〉NOH are actively involved in a regenerative cycle and that this redox couple is responsible for the stability of the polymer whether the initial additive is 〉NO. or 〉NOH. The alkyl hydroxylamine (〉NOR), on the other hand, does not appear to play a significant role in the melt stabilization of the polymer. Quantitative measurements of 〉NOH and 〉NO. concentrations show that, under conditions of both restricted oxygen (CM) and oxygen excess (OM), the concentrations of both species change reciprocally throughout the processing operation. In a closed mixer (CM), the total overall concentration of 〉NO. and 〉NOH remains at a high constant level, whereas in an open mixer (OM), their total concentration decreases continuously to a low level, indicating the irreversible destruction of the redox couple (〉NO. and 〉NOH). The photo-oxidative stability of the polymer was found to depend on the total concentration of the redox couple left in the system after processing in either CM or OM.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 823-830 
    ISSN: 0887-624X
    Keywords: atom transfer radical polymerization ; poly(N-vinylpyrrolidinone-g-styrene) ; macromonomer method ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Atom transfer radical polymerization has been used to prepare well-defined vinyl macromonomers of polystyrene using vinyl chloroacetate as an initiator. Because styrene and vinyl chloroacetate do not copolymerize, no branching or incorporation of the initiator into the backbone was observed. Macromonomers of several molecular weights were prepared and copolymerized free radically with N-vinylpyrrolidinone in varying feed ratios in order to produce poly(NVP-g-Sty) graft copolymers. The macromonomers used were of sufficiently high molecular weight to form physical crosslinks in solvents which favor the hydrophilic NVP, such as water, which prevent the copolymer from dissolving and cause it to swell. These materials, therefore, formed hydrogels of swellabilities in water exceeding 95%, depending on the amount of styrene that was incorporated into the copolymer. Limitations of and alternatives to this method are also discussed. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 823-830, 1998
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 291-298 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The desorption of Trichoderma reesei cellulase from Avicel by a wide range of desorbents was measured. Emphasis was placed on desorption at alkaline pH. A maximum desorption of 65-68% Avicelase activity was achieved by contact with NaOH, pH 10.0, at 40°C for 5 min in the presence of 0.005% Triton X-100 or Tween 80. The design of a suitable desorption process using these conditions is discussed. Glycerol was also effective as a desorbent either alone or in combination with alkali and detergent. However, relatively high concentrations of glycerol were needed and the maximum desorption achieved, 68%, was not significantly greater than that with only alkali and detergent.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 77 (1965), S. 870-870 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 26 (1987), S. 2009-2026 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The loop function ƒ(N), representing the statistical weight of N complementary residues in a closed ring, has been determined by analysis of high-resolution melting curves of a series of recombinant homopoly(A · T)N inserts in pBR322 DNA, where 150 〉 N 〉 50 base pairs (bp). Loops are found more stable and therefore presumably less elastic than expected for an ideal, freely jointed chain. A value of 97 ± 2 bp is obtained for the empirical orientation-stiffness parameter D in the expression for nonideal chains, ƒ(N) = (N + D)-1.7. The 10% increase in apparent stiffness over that of an ideal chain closely coincides with the extent of residual stacking in the loop. It is thus concluded that the more favorable loop energy, such as expected of smaller loops, is due to the incipient helical orientation of some residues, predisposing the loop to reclosure. A quantitative loop function is essential for the prediction and assignment of domains in DNA.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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