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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 1349-1353 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Changes in surface morphology have been studied for Si surfaces treated with CF4/O2 down-flow etching. It has been found that rough Si surfaces can be smoothed and Si trench corners can be rounded off using this CF4/O2 down-flow etching. A SiFxOy layer is formed on the Si surface etched by a down-flow discharged CF4/O2 gas mixture in high O2 concentration. A thick SiFxOy layer is formed at the concave part of the surface, which prevents fluorine atoms from reacting with Si. On the other hand, Si etching proceeds fast at the convex part covered with a thin SiFxOy layer. As a result, a rough Si surface is smoothed and trench corners are rounded off. By applying this treatment to a polycrystalline silicon surface, the leakage current of a SiO2 film grown on it is much reduced.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 19 (1966), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: To investigate the mechanism of frost damage in trees, the temperature fluctualions in the stems and leaves of some wintering trees were recorded with copperconstantan thermocouples.In Sapporo, even the trunk of large elm trees with diameter of 86 cm are frozen during the winter. In a Kalopanax trunk with a diameter of 13.5 cm, the bark temperature on the south side which is exposed to direct sunshine reaches nearly 20°C about midday in midwinter; while, on the north side, the temperature remains nearly the same as the environmental temperature (0 to -5°C). The rise in the bark temperature in trees is considerably affected by factors such as the intensity of sunshine, the environmental temperature, the diameter of the trunk, the side of the trunk which the bark is on, the height above the ground, and the colour of the bark surface, etc. This rise is far less in small twigs, slender stems, and small leaves than in large ones. The south side of the bark 10 to 15 cm above the snow surface or above the ground in a slender stem is exposed to a remarkable fluctuation in temperature, especially when the ground is covered with snow.Even in northern trees, the cortical cells on the south side of trunks and twigs are less resistant to freezing than those on the north.
    Type of Medium: Electronic Resource
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  • 3
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    Paris : Periodicals Archive Online (PAO)
    Revue de littérature comparée. 64:1 bis (1990:janv./mars) 36 
    ISSN: 0035-1466
    Topics: Linguistics and Literary Studies
    Notes: Comptes rendus Histoire et théorie littéraire Littérature et autres arts Thèmes, Mythes, Genres
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plant cell reports 9 (1990), S. 328-331 
    ISSN: 1432-203X
    Keywords: cryopreservation ; dried buds ; desiccation tolerance ; asparagus ; Asparagus officinalis L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dried axillary buds from plantlets of Asparagus lofficinalis L. grown in vitro were successfully cryopreserved. Single node segments (5mm in length) with axillary bud were taken from mature in vitro plantlets. The segments were precultured on solidfied Murashige-Skoog medium (1962) containing 0.7M sucrose at 25 °C in light for 2 days. Thereafter, these precultured segments were subjected to dehydration with silica gel at room temperature for 0 to 24 h. The axillary buds of precultured segments tolerated dehydration to about 14% water content(FW) with 50% lethality (LD50) and the threshold water content at which the dried buds remained alive after exposure to liquid nitrogen was 16.9%(LD50). The maximum rate of survival of cryopreserved buds was about 71% of untreated control. Surviving buds produced shoots and regenerated into plantlets. These results demonstrate the feasibility of cryopreserving dried axillary buds from in vitro plantlets.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-203X
    Keywords: cryopreservation ; apical meristems ; vitrification ; wasabi (Wasabia japonica)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In vitro-grown apical meristems of wasabi (Wasabia japonica Matsumura) were successfully cryopreserved by vitrification. Excised apical meristems precultured on solidified M S medium containing 0.3M sucrose at 20°C for 1 day were loaded with a mixture of 2M glycerol and 0.4M sucrose for 20 min at 25°C. Cryoprotected meristems were then sufficiently dehydrated with a highly concentrated vitrification solution (designated PVS2) for 10 min at 25°C prior to a plunge into liquid nitrogen. After rapid warming, the meristems were expelled into 2 ml of 1.2M sucrose for 20 min and then plated on solidified culture medium. Successfully vitrified and warmed meristems remained green after plating, resumed growth within 3 days, and directly developed shoots within two weeks. The average rate of normal shoot formation amounted to about 80 to 90% in the cryopreserved meristems. This method was successfully applied to three other cultivars of wasabi. This vitrification procedure promises to become a routine method for cryopreserving meristems of wasabi.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-203X
    Keywords: Cryopreservation ; Vitrification ; Asparagus ; In vitro ; cultured bud clusters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A culture line of asparagus forming green bulbous structures consisting of numerous multiple bud clusters designated “bud clusters” was induced from a meristem culture of asparagus (Asparagus officinalis L.cv. Hiroshimagreen, 2n=30). Small cubic segments (2 mm3) cut from bud clusters were cryopreserved using three different cryogenic protocols. Only vitrification produced very high levels of shoot formation after cooling to −196°C. Segments were treated with a vitrification solution (PVS2) at 25°C for 45 min or at 0°C for 120 min prior to a direct plunge into liquid nitrogen. After rapid warming, the segments were expelled into Murashige and Skoog medium containing 1.2 M sucrose for 10 min and then plated on agar shoot outgrowth medium. The average rate of shoot formation of vitrified segments producing normal shoots was near 90% without any preculture and/or cold-acclimation treatment. Revived segments resumed growth within 3 days and developed about three shoots per segment. In vitro-cultured bud clusters appear promising as material for cryopreserving asparagus germplasm.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 27 (1992), S. 6022-6028 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Three-dimensional carbon fibre preforms were infiltrated with silicon carbide from a gas system of CH3SiCl3-H2 using a process of pressure pulsed chemical vapour infiltration. To infiltrate to a deep level, the temperature had to be lowered to 870–900°C, and the hold time per pulse below 1.0 s. Three-dimensional carbon fibre preforms partly filled with SiC fine powder were compared with those without filler. The weight of the preforms increased linearly with increasing number of pulses up to 105 when no filler was present. However, the weight increase slowed down above 8×104 pulses when the filler was used. Preforms with and without SiC filler showed three-point flexural strengths of 160 and 80 MPa after CVI of 105 pulses, respectively. In order to improve the strength, a denser filling of SiC powder is necessary.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-203X
    Keywords: Cryopreservation ; Vitrification ; Nucellar cells ; Navel orange ; Citrus sinensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The nucellar cells of navel orange(Citrus sinensis Osb. var. brasiliensis Tanaka) were successfully cryopreserved by vitrification. In this method, cells were sufficiently dehydrated with highly concentrated cryoprotective solution(PVS2) prior to direct plunge in liquid nitrogen. The PVS2 contains(w/v) 30% glycerol, 15% ethylene glycol and 15% DMSO in Murashige-Tucker medium(MT) containing 0.15 M sucrose. Cells were treated with 60% PVS2 at 25°C for 5 min and then chilled PVS2 at 0°C for 3 min. The cell suspension of about 0.1 ml was loaded in a 0.5 ml transparent plastic straw and directly plunged in liquid nitrogen for 30 min. After rapid warming, the cell suspension was expelled in 2 ml of MT medium containing 1.2 M sucrose. The average rate of survival was about 80%. The vitrified cells regenerated plantlets. This method is very simple and the time required for cryopreservation is only about 10 min.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    International orthopaedics 15 (1991), S. 341-346 
    ISSN: 1432-5195
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Afin d'évaluer les effets de champs électromagnétiques vibratoires (CEMV) sur la prolifération cellulaire et la synthèse du glycosaminoglycan (GAG) et d'étudier le milieu d'action de la stimulation par CEMV dans les cellules, nous avons effectué une série d'expériences sur des cellules de cartilage de croissance de la côte du lapin et sur des cellules de cartilage articulaire humain en culture. Un stimulateur CEMV a été fabriqué en employant une bobine de Helmholz. Des courants électriques en salves pulsées répétitives, avec une largeur de salve de 76 ms, une largeur de pulsion de 230 μs et 6.4 Hz étaient envoyés à travers cette bobine. La force du champ électromagnétique atteignait 0.4 mT (tesla) en moyenne. Les synthèses de DNA et de GAG étaient mesurées par incorporation de thymidine H3 et d'acide sulfurique S35. Les effets sur les cellules traitées par la lidocaine, l'adriamycine et l'irradiation étaient aussi mesurés par un essai formant colonie. La stimulation CEMV d'une durée de 5 jours a favorisé et la prolifération cellulaire et la synthèse du GAG dans les cellules de cartilage de croissance. La stimulation intermittente (fonctionnant on non toutes les 12 heures) les a augmentées de façon encore plus significative. D'autre part, dans les cellules de cartilage articulaire, la stimulation a accéléré la prolifération des cellules; cependant, elle n'a pas augmenté la synthèse du GAG. La stimulation CEMV a favorisé les cellules traitées par la lidocaine de façon plus significative que celles traitées par d'autres agents. Ces résultats montrent de façon évidente que la stimulation intermittente CEMV est plus efficace, aussi bien pour la prolifération cellulaire que pour la synthèse de GAG de cellules de cartilage, que la stimulation continue; et que la stimulation pourrait exercer des effets non pas directement par le noyau, mais par le mécanisme dépendant de la membrane cellulaire. Cette étude apporte une nouvelle donnée de base pour encourager les applications cliniques de CEMV.
    Notes: Summary In order to evaluate the effects of pulsing electromagnetic fields (PEMFs) on cell proliferation and glycosaminoglycan (GAG) synthesis and to study the action site of PEMF stimulation in the cells, we performed a series of experiments on rabbit costal growth cartilage cells and human articular cartilage cells in culture. A PEMF stimulator was made using a Helmholz coil. Repetitive pulse burst electric currents with a burst width of 76 ms, a pulse width of 230 μs and 6.4 Hz were passed through this coil. The magnetic field strength reached 0.4 mT (tesla) on the average. The syntheses of DNA and GAG were measured by 3H-thymidine and 35S-sulfuric acid incorporations. The effects on the cells treated with lidocaine, adriamycin and irradiation were also measured using a colony forming assay. The PEMF stimulation for the duration of 5 days promoted both cell proliferation and GAG synthesis in growth cartilage cells and intermittent stimulation on and off alternatively every 12 h increased them most significantly, while, in articular cartilage cells, the stimulation promoted cell proliferation, but did not enhance GAG synthesis. PEMF stimulation promoted cells treated with lidocaine more significantly than with other agents. These results present evidence that intermittent PEMF stimulation is more effective on both cell proliferation and GAG synthesis of cartilage cells than continuous stimulation, and that the stimulation could exert effects not by nucleus directly, but by the cellular membrane-dependent mechanism. This study provides further basic data to encourage the clinical application of PEMF stimulation on bone and cartilage disorders.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1615-6102
    Keywords: DNA-protein interaction ; Nicotiana tabacum ; Proplastid ; Proplastid-nuclei (nucleoids) ; Transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have developed a novel assay system for analyzing the relationship between the structure and the transcriptional activity of the plastid-nuclei (plastid-nucleoids). The organization of morphologically intact proplastid-nuclei, isolated from tobacco cultured cells (line BY-2), was dispersed by treatment with NaCl at various concentrations and their transcriptional activities were examined by an assay of transcription in vitro and Southern hybridization. Disturbance of the structural organization of the proplastid-nuclei caused changes in both absolute and relative transcriptional activities of plastid genes, a result that suggests that the transcriptional activity of plastid genes may actually be regulated by structural changes in the plastid-nuclei.
    Type of Medium: Electronic Resource
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