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  • 1
    Electronic Resource
    Electronic Resource
    Studies on the role of 24-hydroxylation of vitamin D in the mineralization of cartilage and bone of vitamin D-deficient rats (1981)
    Springer
    Calcified tissue international 33 (1981), S. 489-497 
    Details
    ISSN: 1432-0827
    Keywords: Vitamin D ; Vitamin D deficiency ; Cartilage ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary To test the importance of 24-hydroxylation of vitamin D3 on bone mineralization, rat pups born to vitamin D-deficient females were given either 25-hydroxyvitamin D3 or 24,24-difluoro-25-hydroxyvitamin D3 for 16 days beginning at the time of weaning. Following such treatment analysis of blood samples revealed no detectable 24R,25-(OH)2D3 and 1,25-(OH)2D3 in the rats given the difluoro compound while revealing the expected 24,24-difluoro-25-hydroxyvitamin D3 and 24,24-difluoro-1,25-dihydroxyvitamin D3. The rats given 25-hydroxyvitamin D3 had the expected levels of 25-hydroxyvitamin D3, 24,25-dihydroxyvitamin D3, and 1,25-dihydroxyvitamin D3. Following sacrifice at day 17, postweaning bone mineralization and modeling were studied in long bones using histological methods. Bones taken from vitamin D-deficient rats at the beginning and end of the experimental period had lesions typical of rickets. These included wide growth plates, excessive amounts of osteoid, and metaphyseal fibrosis. Following treatment with either 25-hydroxyvitamin D3 or 24,24-difluoro-25-hydroxyvitamin D3, bone mineralization returned to normal. Growth plate widths and the amount of osteoid on bone surfaces were both substantially reduced and to a similar degree in both treatment groups. Normal cartilage core formation and trabecularization of the metaphyseal primary spongiosa were also restored to a similar degree in both groups. In effect, no difference was observed in any bone parameter studied between the 25-hydroxyvitamin D3- and the 24,24-difluoro-25-hydroxyvitamin D3-treated animals. These results provide strong evidence that 24-hydroxylation of the vitamin D molecule plays little or no role in the modeling and mineralization of bone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409479
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  • 2
    Electronic Resource
    Electronic Resource
    Alkaline and acid phosphatase activities during growth of long bones and mandibles (1972)
    Springer
    Calcified tissue international 9 (1972), S. 173-178 
    Details
    ISSN: 1432-0827
    Keywords: Phosphatase ; Development ; Bone ; Growth ; Rhythm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une étude longitudinale, par séries, est effectuée pour déterminer les activités en phosphatases acide et alcaline dans les os longs et la mandibule. Le pH optimum des deux enzymes se situe respectivement à 10.2 et 5.4 pour les phosphatases alcaline et acide. Des portées synchronisées de rats sont sacrifiées, à raison d'une portée par jour, en commençant au premier jour jusqu'au 25ème jour post-partum. Les spécimens sont analysés en ce qui concerne leur concentration en protéine et leur activité en phosphatases. Une activité de types élevée et faible est observée au niveau du tissu osseux, ainsi qu'un type d'activité faible en phosphatase alcaline, au cours des pics d'activité en phosphatase acide, et vice-versa. Les pics observés suggèrent une concordance entre l'activité en phosphatase et les autres changements biochimiques de la croissance osseuse, au niveau de la matrice organique et la formation minérale. Une étude séparée, tenant compte de la possibilité d'une activité enzymatique rythmique, suggère l'existence d'un rythme diurne court chez les animaux jeunes.
    Abstract: Zusammenfassung Eine serienmäßige Longitudinaluntersuchung wurde unternommen, um die Aktivitäten der alkalischen und sauren Phosphatase in den Röhrenknochen und den Mandibulae von Ratten zu bestimmen. Das pH-Optimum der beiden Enzyme wurde für die alkalische Phosphatase bei 10,2 und für die saure Phosphatase bei 5,4 ermittelt. Synchronisierte und randomisierte Würfe wurden getötet, 1 Wurf pro Tag vom 1.–25. Tag post partum. Die Proben wurden auf ihren Proteingehalt und ihre Phosphatasenaktivität untersucht. Ein Muster niedriger und hoher Aktivität konnte in beiden Knochengeweben beobachtet werden, sowie ein Muster von niedriger Aktivität der alkalischen Phosphatase bei Spitzenwerten der sauren Phosphatase und umgekehrt. Die beobachteten Spitzenwerte lassen einen Zusammenhang vermuten zwischen der Phosphatasenaktivität und den anderen biochemischen Veränderungen, die im wachsenden Knochen auftreten, d. h. Bildung der organischen Matrix und des Minerals. Eine getrennte Untersuchung, welche sich mit der Möglichkeit rhythmischer Merkmale der Enzymaktivität befaßte, läßt vermuten, daß in den ersten Tagen ein schwacher Tagersrhythmus bestehen könnte.
    Notes: Abstract A serial longitudinal study was undertaken to determine the activities of the alkaline and acid phosphatases in the long bones and mandibles. The optimum pH of the two enzymes was recorded at 10.2 and 5.4 for alkaline and acid phosphatase, respectively. Synchronized and randomized litters of rats were killed, 1 litter daily, starting at day 1 to day 25 post partum. Samples were analyzed for protein concentration and activity of the phosphatases. A pattern of low and high activity was observed in both bony tissues, as well as a pattern of low alkaline phosphatase activity during acid phosphatase activity peaks, and vice versa. The observed peaks suggest a correspondence between phosphatase activity and the other biochemical changes occurring in the growing bone, i.e., organic matrix and mineral formation. A separate study, considering the possibility of rhythmic features of the enzyme activity suggests that there may be a small diurnal rhythm at an early age.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02061955
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  • 3
    Electronic Resource
    Electronic Resource
    Development of a two-phase combination fermenter for the conversion of cellulose to methaneIssued as N.R.C.C. No. 21064. (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 25 (1983), S. 1571-1579 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Cellulose degradation to methane under continuous fermentation conditions was compared using fully mixed, fully mixed with solids return, sludge-blanket, and fixed-film fermenters. In fully mixed fermenters, a decrease in hydraulic retention time (HRT) of two weeks or less caused the wash out of anaerobes capable of converting volatile fatty acids to methane, while at increased feeding rates over 1 g/L day the rapid growth of cellulolytic anaerobes upset the balance between acid formation and its conversion to CH4. Circulation of cellulose and difficulty in settling of cellulose with attached bacteria imposed problems in the use of other types of fermenters. On the basis of information obtained from this study, a fermenter which combined a fully mixed phase for cellulose degradation and a fixed-film phase with pre-immobilized bacteria for converting fatty acids to CH4 in one vessel, was devised. Using this fermenter, a mixed culture converted cellulose to CH4 at 4.8 g/L day at a HRT of six days as compared to 0.7 g/L day at a HRT of 28 days in the fully mixed fermenter.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260250611
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  • 4
    Electronic Resource
    Electronic Resource
    Growth of animal cells on microbeads. I. In situ estimation of numbers (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 28 (1986), S. 1466-1473 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Evaluation of the number of anchorage-dependent cells growing on the surface of microbeads kept in suspension in a bioreactor is a tedious procedure fraught with many difficulties. Using the Coulter counter as a biomass probe, this article shows that the number of cells adhering to microbeads can be determined while the cells are still attached.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260281004
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  • 5
    Electronic Resource
    Electronic Resource
    Power requirements of gas-liquid agitated systems (1962)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 8 (1962), S. 262-266 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Power data for dispersion of air in liquids by means of a six-bladed flat blade turbine are presented in the form of a logarithmic plot of actual power consumed against a function of speed, impeller diameter, gas flow rate, and impeller power characteristics. The data are those of Michel (7), Bimbenet (2), Sachs (12), and Oyama and Endoh (10).Turbines of from 3- to 8-in. diameter were run in tanks of from 6.5- to 18-in. diameter, with the D/T never exceeding 0.47. The fluids tested covered a density range of 0.8 to 1.65 g./ml. and a viscosity range of 0.9 to 100 centipoises.Data are also presented on dispersion of air in a 50% by volume batch of carbon tetrachloride in water and dispersion of air in a suspension of Alundum particles in water, and compared with data on water in a similar system.The qualitative effect of a surface active agent is demonstrated in a comparison of data for a 0.1% by weight mixture of Pluronic L-62 in water with data for pure water with the same apparatus.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690080226
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  • 6
    Electronic Resource
    Electronic Resource
    Inamine aus Halogenalkinen und tertiären Aminen (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 76 (1964), S. 537-538 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19640761213
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  • 7
    Electronic Resource
    Electronic Resource
    Collisions of fluorocarbon ions at solid surfaces: Electronic excitation, surface-induced dissociation and chemical sputteringIn recognition of the enormous contribution of John Holmes to ion chemistry and his service to this journal. (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 28 (1993), S. 1021-1033 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Collisions of C3F6+· at self-assembled hydrocarbon, deuterated hydrocarbon and fluorocarbon surfaces yield fragment ions which are characteristics of both electronic excitation and vibrational excitation. Direct electronic excitation is indicated by loss of F·, which has been shown previously to be diagnostic of this type of excitation process. Electronic excitation is favored by low-energy collisions at the hydrocarbon surface. Even the change to the corresponding deuterated surface produces a large effect in favor of the normal vibrational excitation process. This change in mechanism with the nature of the target shows up as a dramatic isotope effect in the surface-induced dissociation (SID) mass spectra. The control over the excitation process exhibited by the effective mass of the target is probably exerted through its effect on the relative velocity of the collision partners. The fluorinated surfce is more effective than the others in conversion of translational into internal energy and in minimizing ion loss through neutralization and other processes which compete with SID. The fluorinated surfaces yield spectra that are largely free from chemical sputtering, a process which occurs even at ultra-high vacuum for stainless-steel surfaces which are not rigorously cleaned. The internal energy deposition associated with chemical sputtering increases with increaisng collision energy. Several of the fluorocarbon fragment ions generated from perfluoropropylene have also been examined at self-assembled monolayer surfaces and they are well behaved in their SID and chemical sputtering reactions. This in contrast to the low efficiency of SID and high sputtering efficiency observed in previous studies at uncharacterized multi-layer hydrocarbon-covered surfaces.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210281009
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  • 8
    Electronic Resource
    Electronic Resource
    Long-term osteopenic changes in cancellous bone structure in ovariectomized rats (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 236 (1993), S. 433-441 
    Details
    ISSN: 0003-276X
    Keywords: Bone ; Cancehous bone ; Osteopenia ; Ovariectomy ; Morphometry ; Rats ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Cancellous bone mass decreases following ovariectomy in rodents, providing a useful model for post-menopausal bone loss in humans. This study describes and quantifies the longer-term changes in cancellous bone structure in the ovariectomized (OVX) rat. Rats were OVX or sham-OVX at 100 days of age and bones were collected 540 days later. Lumbar vertebral bodies were prepared for microradiography and structural analyses (nodal analyses and star volume analyses) of cancellous bone. Proximal humerii were prepared for scanning electron microscopy (SEM). Microradiography confirmed the loss of cancellous bone from the central spongiosa regions of the vertebral bodies and the humerii in the OVX rats. Changes in trabecular structural elements included relative increases in the number of free to free, cortical to free, cortical to node struts and decreases in the node to node struts in the OVX animals compared with controls. There were increases in average lengths of the node to free, node to node, and free to free trabecular struts in the OVX animals. The marrow star volume was increased in the OVX animals indicating a greater trabecular separation in these animals compared with controls. Viewed by SEM, metaphyseal trabeculae in the controls consisted of rods and plates but in the OVX animals the remaining trabeculae were mostly longitudinal rods with smaller transverse connecting rods. The remaining bone in the OVX animals was found in the lateral metaphyseal areas and is consistent with maintenance of the structural capacity of the bone. These long-term changes in cancellous bone structure are likely due to the continuation of functional skeletal loading but a decrease in gonadal hormones resulting in a decreased necessity to maintain a skeletal mineral store for reproduction (e.g., pregnancy and lactation). © 1993 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092360303
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  • 9
    Electronic Resource
    Electronic Resource
    Comparison of osteopenic changes in cancellous bone induced by ovariectomy and/or immobilization in adult rats (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 239 (1994), S. 243-254 
    Details
    ISSN: 0003-276X
    Keywords: Bone ; Ovariectomy ; Immobilization ; Bone resorption ; Bone formation ; Rats ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: Ovariectomy (OVX) and immobilization (IMM) in rats are useful models of osteopenia, replicating some aspects of osteoporosis in humans. The purpose of this study was to compare changes in cancellous bone after OVX and/or IMM.Methods: Differences in cancellous bone were determined at 6 and 12 weeks after OVX or IMM. Comparisons were also made when rats were ovariectomized or immobilized for 6 weeks and then immobilized (OVX/IMM) and ovariectomized (IMM/OVX), respectively, for 6 more weeks. The femurs were used to determine bone mineral content (BMC) using single photon absorptiometry (SPA) and for scanning electron microscopy (SEM). Tibias were collected for microradiography, image analysis, and histomorphometry of metaphyseal cancellous bone.Results: Six and 12 weeks after OVX, there was less cancellous bone mass, compared with controls, as indicated by SPA, SEM, microradiography, image analyses, and histomorphometry. Bone was lost primarily from the central metaphyseal regions in the OVX animals, whereas the loss occurred throughout the metaphyses in the IMM animals. There were more rodlike bone spicules and fewer platelike trabecule in the OVX and IMM groups compared with controls. Differences in the structural aspects of the cancellous bone, including differences in the types of bone struts and marrow star volumes, indicated less trabecular connectivity and greater trabecular separation in the OVX and IMM animals, compared with controls. Endochondral growth indices in the IMM groups tended to be less, whereas the OVX groups tended to be greater than controls. Cancellous bone formation rates were generally greater in the OVX groups but less in the IMM groups compared with controls. Osteoclastic resorption surfaces were substantially elevated in the IMM and OVX groups, particularly the IMM groups. Changes reflecting OVX and IMM, independently, were apparent in the OVX/IMM and IMM/OVX groups and indices of osteopenia were different from controls, including less bone mass, trabecular connectivity, and greater trabecular separation, bone turnover rates, and osteoclastic surface.Conclusions: These results demonstrate differences in the osteopenic changes that occur in cancellous bone following OVX or IMM. The changes were generally more dramatic in the IMM than in the OVX animals. When OVX and IMM were applied in combination, the osteopenic changes are particularly severe, emphasizing the importance of mechanical usage even with a deficiency of gonadal hormones. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092390303
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  • 10
    Electronic Resource
    Electronic Resource
    Tough, transparent heat- and flame-resistant thermoplastics via silicone block-modified bisphenol fluorenone polycarbonatePresent at Conference on Aerospace Transparent Materials and Enclosures, Atlanta, Georgia, November 18-21, 1975, sponsored by Air Force Materials Laboratory and Air Force Flight Dynamics Laboratory. (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 20 (1976), S. 3275-3293 
    Details
    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: Bisphenol fluorenone carbonate-dimethylsiloxane block polymers have been synthesized by interfacial condensation of phosgene with various mixtures of BPF-endcapped silicone oligomers and free BPF or its monosodium salt. The multisequence block polymers described here contain 7% to 27% silicone consisting of blocks of number-average degree of polymerization 10 to 40. Cast films are clear and colorless. Two glass temperatures are evident in each resin, one at about -100°C for the silicone microdomains and one at temperatures as high as 275°C for the polycarbonate matrix. While BPF polycarbonate is brittle, block polymers with as little as 10% silicone yield by shear deformation before breaking. Ultimate elongations are increased by preorientation at silicone contents above 15%. At temperatures far removed from BPF carbonate domain Tg's, both modulus and yield stress decrease with increasing silicone content, independent of block length, in a manner rationalized quantitatively by hard phase-soft phase continuum models. Ultimate tensile elongation, impact toughness, and plane strain stress intensity factors increase with silicone content, through a stress whitening mechanism. At higher silicone contents, shear deformation enhances tensile elongation and impact toughness. Heat distortion temperatures of 200°C or more are achieved. Flame resistance exceeds that of any known nonhalogenated resin. The resins are extrudable and injection moldable with only minor changes in color, transparency, and strength properties. Resins with 15% to 20% silicone can have a balance of properties that makes them attractive as tough, transparent heat- and flame- resistant engineering plastics.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1976.070201209
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