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  • 1
    Electronic Resource
    Electronic Resource
    Activities of carboxylating enzymes in the CAM species Opuntia ficus-indica grown under current and elevated CO2 concentrations (1994)
    Springer
    Photosynthesis research 40 (1994), S. 223-229 
    Details
    ISSN: 1573-5079
    Keywords: Crassulacean acid metabolism ; CO2 enrichment ; Opuntia ficus-indica ; PEPCase ; Rubisco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Responses of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and phosphoenolpyruvate carboxylase (PEPCase) to an elevated atmospheric CO2 concentration were determined along with net CO2 uptake rates for the Crassulacean acid metabolism species Opuntia ficus-indica growing in open-top chambers. During the spring 13 months after planting, total daily net CO2 uptake of basal and first-order daughter cladodes was 28% higher at 720 than at 360 μl CO2 l-1. The enhancement, caused mainly by higher CO2 assimilation during the early part of the night, was also observed during late summer (5 months after planting) and the following winter. The activities of Rubisco and PEPCase measured in vitro were both lower at the elevated CO2 concentration, particularly under the more favorable growth conditions in the spring and late summer. Enzyme activity in second-order daughter cladodes increased with cladode age, becoming maximal at 6 to 10 days. The effect ofelevated CO2 on Rubisco and PEPCase activity declined with decreasing irradiance, especially for Rubisco. Throughout the 13-month observation period, O. ficus-indica thus showed increased CO2 uptake when the atmospheric CO2 concentration was doubled despite lower activities of both carboxylating enzymes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00034772
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  • 2
    Electronic Resource
    Electronic Resource
    Recovery of photosynthetic reactions after high-temperature treatments of a heat-tolerant cactus (1988)
    Springer
    Photosynthesis research 18 (1988), S. 277-286 
    Details
    ISSN: 1573-5079
    Keywords: CO2 uptake ; high-temperature acclimation ; Opuntia ficus-indica ; photosystems I and II ; whole chain electron transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Inhibition and recovery of net CO2 uptake and three photosynthetic electron transport reactions as well as plant survival following high-temperature treatments were investigated for Opuntia ficus-indica. For plants maintained at 30°C/20°C day/night air temperatures, treatment at 60°C for 1 h irreversibly inhibited net CO2 uptake and photosynthetic electron transport, resulting in plant death in about 60 days. When a plant maintained at 30°C/20°C was treated at 55°C for 1 h, net CO2 uptake was completely inhibited 1 d after the treatment but fully recovered in 60 d. Differential inactivation of photosystem (PS) I, PSII, and whole chain electron transport activities occurred; PSI was the most tolerant of 55°C and took the least time (45 d) for total recovery. All 30°C/20°C plants survived a 1-h treatment at 55°C, although some pale green areas were observed on the cladode surfaces. In contrast to growing at 30°C/20°C, plants acclimated to 45°C/35°C survived 60°C for 1 h without showing any necrotic or pale green areas on the cladode surfaces. When such a plant was transferred to 30°C/20°C following the high-temperature treatment, recovery in net CO2 uptake began in 1 d and progressed to complete recovery by 30 d. Growth temperatures thus influence the possibility for recovery of photosynthetic reactions and ultimately the survival of O. ficus-indica following a high-temperature exposure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00034832
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  • 3
    Electronic Resource
    Electronic Resource
    Einfluß der Korngröße auf mechanische Eigenschaften und den ungeschmierten reversierenden Gleitverschleiß von Al2O3-Keramik (1992)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 23 (1992), S. 329-338 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Influence of grain size on mechanical properties and dry oscillating sliding wear of Al2O3-ceramicsSpecimens with average grain sizes varying between about 0.8 μm and 12 μm were produced by cold isostatic pressing of high purity Al2O3-powder followed by sintering between 1300°C and 1700°C. Hardness, Young's modulus, bending strength and fracture toughness were measured as a function of average grain sizes. Tribological tests were carried out on the different microstructures at normal laboratory air and room temperature by using a ring-on-block tribometer.Experimental results showed the dependence of mechanical properties on grain size, hardness and bending strength obeying a Hall-Petch type relation, approximately. Coefficient of friction was relatively independent of grain size under the test conditions used. However, wear intensity increased substantially if a critical grain size was surpassed. This was due to a change in mechanisms of material removal which was confirmed by scanning electron microscopical studies of the worn surfaces.
    Notes: Aus hochreinem Al2O3-Pulver wurden durch kaltisostatisches Pressen und Variation der Sintertemperatur zwischen 1300°C und 1700°C Formkörper mit unterschiedlichen mittleren Korngrößen zwischen etwa 0,8 und 12 μm hergestellt. Untersucht wurde der Einfluß der Korngröße auf mechanische und tribologische Eigen-schaften.Die Ergebnisse zeigten, daß mechanische Eigenschaften wie Härte, E-Modul, Biegebruchfestigkeit und Bruchzähigkeit von der Korngröße bzw. den Sintertemperaturen abhingen, wobei im Fall der Härte und Bruchfestigkeit näiherungsweise eine Hall-Peteh-Beziehung vorlag. Während die Reibungszahl relativ unabhängig von der Korngröße war, trat in der Verschleißintensität aufgrund geänderter Mechanismen ein starker Anstieg mit zunchmender Korngröße auf. Rasterelektronenmikroskopische Untersuchungen zeigten, daß der Verschleiß durch plastische Verformung, Mikrobruch, Kornfragmentierung und Deckschichten beeinflußt wurde.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19920230909
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  • 4
    Electronic Resource
    Electronic Resource
    Mn(III) - porphyrin-based thiocyanate-selective membrane electrodes: Characterization and application in flow injection determination of thiocyanate in saliva (1989)
    Weinheim : Wiley-Blackwell
    Electroanalysis 1 (1989), S. 477-484 
    Details
    ISSN: 1040-0397
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The response properties of a new thiocyanate-selective solvent-polymeric membrane electrode are reported. The membrane contains (5,10,15,20-tetrakis(2,4,6-triphenylphenyl)porphyrinato)manganese(III) chloride (Mn[TPPP]CI) in a plasticized polyvinyl chloride matrix. The electrode deviates from the Hofmeister selectivity pattern by responding to thiocyanate preferentially over inorganic anions (perchlorate, chloride, iodide, and bromide) and several organic anions often present in biological samples (ascorbate, citrate, urate, and salicylate). The performance of this electrode as an ion-selective detector in a low-dispersion, flow-injection system is also evaluated. While selectivity in such a nonequilibrium flow arrangement is found to be somewhat different than that observed under equilibrium conditions, the electrode's response and selectivity is still adequate to allow for measurement of thiocyanate in biological samples. This application is demonstrated via the flow-injection analysis (FIA) detection of thiocyanate in 22 human saliva samples with good correlation to a classical colorimetric method (r = 0.981).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elan.1140010602
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  • 5
    Electronic Resource
    Electronic Resource
    Potentiometric anion selectivities of polymer membranes doped with indium(III)-porphyrins (1991)
    Weinheim : Wiley-Blackwell
    Electroanalysis 3 (1991), S. 909-916 
    Details
    ISSN: 1040-0397
    Keywords: Indium ; potentiometry ; membrane ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The potentiometric anion responses of polymeric membranes doped with various indium (III)-porphyrin structures are examined. The appropriate membranes are prepared by incorporating 1.0 wt % of the In(III)-porphyrins in plasticized poly(vinyl chloride) films. When such membranes are incorporated within standard ion selective electrode bodies, the resulting electrodes display non-Hofmeister anion selectivity, with a particularly enhanced and super-Nernstian response to chloride. Among those porphyrins investigated, membranes doped with chloro(octaethylporphyrinato)indium(III) yield the largest and most reproducible potentiometric anion responses. These same membrane electrodes exhibit negligible response to protons (or hydroxide) in the range of pH 4.5-9.0. When utilized as a flow-injection detector in conjunction with a protein diluent/buffer stream, the In(III)-porphyrin based electrodes may be used to determine chloride levels in human serum samples.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elan.1140030906
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of the polyamide molecular structure on the performance of reverse osmosis membranes (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 1821-1830 
    Details
    ISSN: 0887-6266
    Keywords: reverse osmosis ; poly(aminostyrene) ; benzenediamines ; acyl chlorides ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Thin-film composite reverse osmosis membranes of polyamides were prepared by interfacial polymerization. Various benzenediamines and poly(aminostyrene) were interfacially reacted with various acyl chlorides to prepare a skin layer of composite membranes. Among the membranes prepared from the structural isomeric monomers of benzenediamines and acyl chlorides, i.e., the same chemical composition but different in the position of functional groups on the aromatic ring, the membrane with the best salt rejection was obtained when the reacting groups forming amide are located at the same position on the aromatic ring. Membranes prepared by interfacially reacting various diamines with trimesoyl chloride revealed that the salt rejection depends on the linear chain structure of polyamides and network formed by crosslinking. Membranes obtained by interfacial polymerization of poly(aminostyrene) with trimesoyl chloride showed higher water flux but lower salt rejection than those obtained by interfacial polymerization of various benzenediamines with trimesoyl chloride. Membranes obtained here showed the typical trade-off behavior between salt rejection and water flux. However, membranes prepared by interfacially reacting trimesoyl chloride with a mixture of poly(aminostyrene) and m-phenylenediamine or a mixture of poly(aminostyrene), m-phenylenediamine, and diaminobenzoic acid showed a performance advantage over usual membranes, i.e., a large positive deviation from the usual trade-off trend. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1821-1830, 1998
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Application of extracorporeal shock wave lithotripter (ECSWL) in orthopedics. I. Foundations and overviewParts of this paper were presented at the Society for Biomaterials and Orthopedic Research Society Annual meetings. (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Biomaterials 2 (1991), S. 115-126 
    Details
    ISSN: 1045-4861
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: In this paper we have reviewed the feasibility of using a shock wave lithotripter to loosen the interface between the bone and acrylic bone cement for revision arthroplasty. We have reviewed the physics of shock wave and its applications in medicine, especially its interaction with tissues. The calculations show that the energy is greatly reduced at the interface both in the soft tissue-bone interface and cement-bone interface. On the other hand, a tensile and compressive pressure can be operated at the cement-bone interface that can cause the interface to break if the pressure exceeds the tensile strength of the cement-bone interface.Subsequent papers will deal with in vitro and in vivo application of the shock wave in the treatment of the cement-bone interface in order to weaken it and consequently for easier extraction of bone cement from the intramedullary canal.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jab.770020207
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  • 8
    Electronic Resource
    Electronic Resource
    Application of extracorporeal shock wave lithotripter (ECSWL) in orthopaedics. II. Dose-response and pressure distribution measurements (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Biomaterials 2 (1991), S. 161-170 
    Details
    ISSN: 1045-4861
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: In order to apply the extracorporeal shock wave lithotripter (ECWSL) technique to the loosening of the bone-cement interface for the extraction of the cement during revision arthroplasty it is essential to know the dose-response characteristics. The present study shows that the number of shocks needed to break the interface between a 2- and 6-mm-thick bovine femoral bone and bone cement is similar to the fatigue behavior of a material, that is, Log(N) = C(kV) + D, where N is the number of shock impulses, kV is the power setting of the lithotripter machine in kilovolts, and C and D are constants. Iso-pressure distribution of the traveling shock wave front through a simulated bone in a Plexiglass® tube using Fuji® pressure film showed quantitative pressure contours from which one can understand the effective area of shock wave and its distribution. The most effective area of the shock wave was about 1.5 cm in diameter at 23 and 25 kV with pressure at least 7.0 MPa which is more than sufficient to break the bone-cement interface in tension.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jab.770020304
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  • 9
    Electronic Resource
    Electronic Resource
    Application of extracorporeal shock wave lithotripter (ECSWL) in orthopaedics. III. In Vitro and In Vivo studiesPart of this work was presented to the Society for Biomaterials and Orthopedic Research Society annual meetings. (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Biomaterials 2 (1991), S. 171-181 
    Details
    ISSN: 1045-4861
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The present study was conducted to compare the push-out strength of the treated and control samples obtained after implantation of intramedullary rod in canine femurs with bone cement to simulate the femoral stem implantation for 2 weeks, 3 and 6 months. Contralateral femur served as control. The result showed a significant decrease in push-out interfacial strength after shock wave treatment (average 48.4% decrease compared with control, p 〈 0.0001) which is similar to the in vitro results. There was no significant difference if the shock treatment was applied and left for 2 weeks or 4 weeks compared to the ones tested immediately after sacrifice. There were some soft tissue damage immediately following shock treatment in the focal area but this returned to normal in 2 weeks. Human cadaveric femoral bones and the canine bone (the dosage level was higher for the human bone than canine). The number of impacts used to extract the bone cement plug out of a human femur segment (5-cm long) decreased about 68% at 23 and 25 kV treatment power level. These preliminary studies indicate that the shock wave can be utilized to reduce the interfacial strength of the bone and bone cement although more studies are needed to assess its efficacy in terms of cost, long-term effect on patients and the exact mechanism of the loosening before this technique can be used clinically.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jab.770020305
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  • 10
    Electronic Resource
    Electronic Resource
    Biodegradable sponges for hepatocyte transplantation (1995)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 959-965 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Liver cell transplantation may provide a means to replace lost or deficient liver tissue, but devices capable of delivering hepatocytes to a desirable anatomic location and guiding the development of a new tissue from these cells and the host tissue are needed. We have investigated whether sponges fabricated from poly-L-lactic acid (PLA) infiltrated with polyvinyl alcohol (PVA) would meet these requirements. Highly porous sponges (porosity = 90-95%) were fabricated from PLA using a particulate leaching technique. To enable even and efficient cell seeding, the devices were infiltrated with the hydrophilic polymer polyvinyl alcohol (PVA). This reduced their contact angle with water from 79 to 23°, but did not inhibit the ability of hepatocytes to adhere to the polymer. Porous sponges of PLA infiltrated with PVA readily absorbed aqueous solutions into 98% of their pore volume, and could be evenly seeded with high densities (5 × 107 cells/mL) of hepatocytes. Hepatocyte-seeded devices were implanted into the mesentery of laboratory rats, and 6 ± 2 × 105 of the hepatocytes engrafted per sponge. Fibrovascular tissue invaded through the devices' pores, leading to a composite tissue consisting of hepatocytes, blood vessels and fibrous tissue, and the polymer sponge. © 1995 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820290807
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