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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 27 (1901), S. 209-253 
    ISSN: 0863-1778
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 5 (1963), S. 131-146 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A sensitive cup plate assay method for lysine on large plates using S. faecalis ATCC 6057 as the test organism is described in detail. Well-defined zones of dense growth were obtained in a rectilinear dose - response range from 5 to 3000 μg. of L-lysine/ml. Comparative assays on twelve different samples were carried out using the turbidimetric tube assay method with Leuc. mesenteroides ATCC 8042 and the cup plate method with S. faecalis ATCC 6057. Good agreement between the two assay methods was obtained for five samples. For the remaining seven samples the tube assay values were appreciably higher than those obtained by the plate method. This discrepancy is discussed. Pure lysine added to various sample extracts could be quantitatively recovered. The specificity of the lysine requirement of S. faecalis ATCC 6057 in the plate assay was also investigated. Under certain experimental conditions, a weak and variable response was obtained with D-lysine and the polyamines cadaverine, spermine, and spermidine. There was generally no difficulty in distinguishing the D-lysine and polyamine growth zones from the L-lysine growth zones. This growth effect of D-lysine and polyamines could be diminished and even completely abolished by increasing the DL-hydroxylysine hydrochloride level in the plate medium. The lysine peptides glycyl-L-lysine and L-lysylglycine gave excellent growth zones of the same appearance as those produced by L-lysine. The activity of these two peptides in cup tests were on a molar basis about 70% of that of L-lysine.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 5 (1963), S. 147-165 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A number of factors was found to affect the cup plate assay for lysine with Streptococcus faecalis ATCC 6057. Hydroxylysine, aspartic acid, and Tween 80 were found to be among the essential components of the assay medium. Removal of any of these three components produced diffuse growth zones or otherwise unsatisfactory plates. The inclusion of asparagine and additional dipotassium phosphate to the medium was found to be advantageous but not an absolute requirement. It was important not to autoclave the hydroxylysine and the additional dipotassium phosphate together with the rest of the assay medium, but to add these components to the sterilized medium immediately before pouring the plates. With certain concentrations of hydroxylysine in the medium, the addition of L-glutamine was found to potentiate the effect of hydroxylysine and thereby improve the lysine plates. The effect of graded amounts of the above mentioned medium components and of the pH of the assay medium was also studied. Increasing the sterilization time of the medium from 5 to 10 min. at 120°C. improved the readability of the lysine plates and led to more easily reproducible results. Factors influencing the preparation of the inoculum for the lysine plates were also studied: the age of the stab culture, the amount of inoculum used per plate, and the influence of the nature of the suspension medium used for washing the inoculum.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 4 (1962), S. 23-36 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The ability of a number of Ustilago species, especially Ustilago maydis (DC.) Cda., to produce lysine and threonine was investigated. The organisms were grown in shake flasks or in 10-l. fermentors. Lysine and threonine were found to be excreted into the medium both in the free and bound form. The bound amino acids could be released by acid hydrolysis or by enzymes from autolyzed cells. The optimal conditions for the release by autolysis were, in the case of Ustilago maydis (DC.) Cda., pH 4.3 and 45°C. An enzyme that could liberate lysine from the bound form(s) occurring in the broth was extracted from cells of Ustilago maydis (DC.) Cda. It exhibited an apparent pH optimum near 4.0. The effect of pH and temperature during the growth phase on the yield of lysine and threonine was studied in 10-l. fermentations.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The ability of Ustilago maydis (DC.) Cda. to grow and to produce lysine and threonine was investigated in shake flask cultures. Growth and production of lysine and threonine increased markedly when aeration was increased. The optimal ratio of glucose to diammonium phosphate in the medium seemed to be approximately 10:1. Ammonium phosphate, ammonium sulfate, ammonium chloride, ammonium nitrate, sodium nitrate, urea, aspartic acid, glutamic acid, and glycine were readily used as nitrogen sources. Growth and amino acid production was poor on ammonium carbonate, ammonium acetate, ammonium citrate, trimethylamine, and betaine.U. maydis (DC.) Cda. was found to grow on a number of different carbohydrates. Besides D-glucose the organism could utilize D-mannose, D-galactose, D-fructose, L-arabinose, D-xylose, D-ribose, sucrose, maltose, and the polyalcoholes D-sorbitol, D-mannitol, and i-inositol. Pectin, dextrin, and corn starch treated with α-amylase could also be used but not untreated corn starch or lactose, cellobiose, D-sedoheptulose, glycerol, or D-glucosamine. The formation of lysine and threonine was better with disaccharides and hexoses than with pentoses.No specific effects on the formation of lysine and threonine could be observed from changes in the concentration of calcium, sodium, potassium, magnesium, zinc, iron, copper, manganese, cobalt, or molybdenum. The requirement of metal ions for growth is discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 31 (1991), S. 1057-1063 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: An attempt was made to improve the properties of filament wound glass fiber-epoxy composites by addition of carboxyl-terminated-butadiene-acrylonitrile (CTBN)-rubber to the matrix. The interlaminar GIc of unidirectional glass fiber-epoxy increased significantly with CTBN addition whereas the flexural strength decreased. The weepage stress in hoop loading of ±50 degree angle-ply pipes was higher for unmodified as compared with 10 phr CTBN-modified epoxy matrix pipes. However, the strain at weepage and the stress and strain at nonlinearity were higher for the pipes based on toughened epoxy. The reason for the lower weepage stress is that, although the toughened matrix pipes show higher resistance to cracking, their stiffness is lower. The addition of small amounts of CTBN-rubber (about 5 percent by weight is suggested) to the present epoxy matrix for filament winding can be done with only a minor increase in viscosity. This is a way of toughness enhancement for applications where the matrix stiffness reduction and increased moisture absorption are of minor importance.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A specific assay is described for the confirmatory identification of danofloxacin residues in edible tissues of cattle and chicken. The assay utilizes on-line microbore high-performance liquid chromatography and pneumatically assisted electrospray tandem mass spectrometry (MS/MS). Collision-induced dissociation of the danofloxacin protonated molecule results in two significant daughter ions. Monitoring both ions provides the specificity required for this confirmatory assay. Optimum electrospray and MS/MS operating conditions permitted the specific monitoring of danofloxacin and the confirmation of its residues in chicken and cattle liver extracts down to 50 ppb. The analysis of control liver or the commercially available antibacterial quinolones enrofloxacin and its metabolite ciprofloxacin gave no response under the assay conditions. The ratios of the two daughter ions were similar for danofloxacin standard solutions, fortified tissues and incurred tissues.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 41 (1998), S. 574-583 
    ISSN: 0021-9304
    Keywords: artificial implants ; calcium phosphates ; titanium ; osteointegration ; arthroplasty ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The early healing phase of hard tissue implants is important to their long-term success. Problems during this phase can result in a so-called primary biological failure. In 24 New Zealand white rabbits, the healing in cortical bone of noncoated TiAlV and cpTi cylinders and of TiAlV cylinders plasma-spray-coated with hydroxyapatite (HA) or fluorapatite (FA) was investigated histologically and histomorphometrically after 3, 7, 14, and 28 days. Histomorphometry consisted of bone contact measurements and the use of a new semi quantitative scoring system that discriminated various tissues in contact with the implant. The results demonstrated that the most important parameter in initial implant healing is the bone itself and not the characteristic of the implanted material. For all implants, healing was characterized by a sequence of hematoma formation, bone resorption, and new bone formation where the initial press-fit situation revealed more bone-implant contact than after 7 and 14 days. There were only minor differences between the implant types: the new bone formation directly on the implant surface was qualitatively histologically superior to the CaP-coated implants, but this could be confirmed with the scoring method only for the HA-coated implants. It is concluded that initial press-fit fixation in cortical bone is not an end situation; rather, what happens is that as a result of interface remodeling, early postoperatively implant integration in the bone will decrease temporarily prior to a subsequent phase of new bone formation. © 1998 John Wiley & Sons, Inc. J. Biomed Mater Res, 41, 574-583, 1998.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 24 (1990), S. 847-860 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Ion implantation modifies the surface properties of different materials. We have compared the biological properties of titanium implanted with nitrogen with those of pure titanium. Implants were inserted in the abdominal wall of rats. The implants with surrounding tissue were excised after 1 and 6 weeks, and embedded in epoxy resin. The bulk metal was removed electrochemically and the tissue cut for light and electron microscopy. Using this technique the implant surface, formed by a thin oxide layer, remains and appears in sections as a dense line. After 1 week both types of implants were surrounded by a fluid space containing proteins and scattered macrophages but few polymorphonuclear granulocytes. The fluid space was wider around ionimplanted titanium (52 ± 22 μm) than around pure titanium implants (15 ± 3 μm). After 6 weeks the fluid space had largely disappeared around both type of implants. Around pure titanium implants macrophages and fibroblasts, quantified in 1-μm-thick sections in the light microscope, were present in about the same concentration in the inner tissue zone (within 25 μm from the implant surface). Around ion-implanted titanium macrophages predominated in the inner zone and multinuclear giant cells were present in almost all sections. Around both type of implants fibroblasts increased and macrophages decreased with increasing distance from the surface. In the electron microscope macrophages close to the surface of pure titanium were of small size and had an ultrastructure indicating a low activity. Macrophages close to ion-implanted titanium were large and had an active appearance as indicated by the presence of large amounts of endoplasmic reticulum and large Golgi areas in the cytoplasm. Our observations indicate that modification of the surface properties of titanium implants by ion implantation changes the biological properties.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 18 (1992), S. 381-386 
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A superlattice sample consisting of 200 alternating 5 nm layers of GaAs and Al0.45Ga0.55As was analyzed to explore some of the factors affecting depth resolution in rotational depth profiling by AES, including coincidence of sample rotation and probe beam axes, stability of analysis position and probe beam current density. Because of the periodic nature of the layers involved, it was possible to detect very small (〈 2 nm) changes in surface topography. A mathematical model is proposed which explains the unusual features observed in the AES profile.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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