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101.
Production of fuel alcohol from oats by fermentation   总被引:1,自引:0,他引:1  
Very high gravity (>30 g dissolved solids per 100 ml) mashes were prepared from hulled and hulless oats and fermented at 20° C with active dry yeast to produce ethanol. Excessive viscosity development during mashing was prevented by hydrolyzing -glucan with crude preparations of -glucanase or Biocellulase. Both these preparations possessed endo--glucanase activity. By using these enzymes and by decreasing the water to grain ratio, very high gravity mashes with low viscosity were prepared. Unlike wheat and barley mashes, oat mashes contained sufficient amounts of assimilable nitrogen to promote a fast rate of fermentation. The free amino nitrogen (FAN) content of oat mash could be predicted by the equation, mg FAN L–1=8.9n wheren is the number of grams of dissolved solids in 100 ml of mash supernatant fluid. Ethanol yields of 353.2±3.7 L and 317.6±1.3 L were obtained per tonne (dry weight basis) of hulless (59.8% starch) and hulled (50.8% starch) oats respectively. The efficiency of conversion of starch to ethanol was the same in normal and very high gravity mashes.  相似文献   
102.
本文对103例锰作业工人测定了血液流变学中的七项指标,结果表明:全血粘度(高切、低切)、血浆粘度、红细胞压积、纤维蛋白原、红细胞电泳、血小板粘附、血沉等项指标,均明显高于正常对照组(P<0.01),证实锰作业工人普遍存在高粘滞血症,为临床治疗锰中毒开辟新的途径提供了依据。对其中的52例锰中毒(包括症状较重的观察对象),用清栓酶治疗后,复查其七项指标与治疗前比较,均有明显下降(P<0.01),其症状与体征得以改善,进一步说明清栓酶是治疗锰中毒的理想药物之一。  相似文献   
103.
Energetic constraints and foraging efficiency   总被引:2,自引:1,他引:1  
Previous research considers foraging options that differ interms of their gross rate of gain b and rate of energy expenditurec. This research argues that maximizing efficiency b/c willmaximize net energetic gain when there is an upper limit onthe amount of energy that can be assimilated. This analysisdoes not include the expenditure during the time for which theanimal is unable to forage because of this constraint. Whenthis expenditure is included, maximizing efficiency is no longeroptimal. Instead the best feeding option is the one with thehighest value of b/(cc1), where c, is the metabolicrate when the animal is not foraging.  相似文献   
104.
Summary Chickpea was micropropagated by axillary shoot proliferation (ASP) and modified single node culture (MSNC) methods. Maximum propagule proliferation occurred on Murashige and Skoog (MS) medium enriched with 1–10 μM N6-benzyladenine and 0.01 μM α-naphthaleneacetic acid. The propagules were rooted on MS medium containing 1 μM 3-indolebutyric acid and B5 vitamins. Regenerated plants were fertile and phenotypically similar to control plants grown from seed. The MSNC method was four times more efficient than the ASP method in terms of the number of plants produced per explant.  相似文献   
105.
Microwave evoked body movements were studied in mice. A resonant cavity was used to provide head and neck exposure of the mouse to pulsed and gated continuous wave (CW) 1.25 GHz microwaves. No difference in response to pulsed and gated CW stimuli of equal average power was found. The incidence of the microwave evoked body movements increased proportionally with specific absorption (dose) when the whole-body average specific absorption rate was at a constant level (7300 W/kg). Under a constant average specific absorption rate, the response incidence reached a plateau at 0.9 kJ/kg. For doses higher than 0.9 kJ/kg, response incidence was proportional to the specific absorption rate and reached a plateau at 900 W/kg. Body movements could be evoked by a single microwave pulse. The lowest whole-body specific absorption (SA) tested was 0.18 kJ/kg, and the corresponding brain SA was 0.29 kJ/kg. Bulk heating potentials of these SAs were less than 0.1 °C. For doses higher than 0.9 kJ/kg, the response incidence was also proportional to subcutaneous temperature increment and subcutaneous heating rate. The extrapolated absolute thresholds (0% incidence) were 1.21 °C temperature increment and 0.24 °C/s heating rate. Due to high subcutaneous heating rates, these microwaves must be perceived by the mouse as an intense thermal sensation but not a pain sensation because the temperature increment was well below the threshold for thermal pain. Results of the present study should be considered in promulgation of personnel protection guideline against high peak power but low average power microwaves. © 1994 Wiley-Liss, Inc.  相似文献   
106.
Social insects such as ants use trial-marking and trail-following to organize the behaviour and movement patterns of a large population. Since behaviour has to meet needs of the population in a changing environment, the type of trail networks formed must be adaptable. Both solitary foraging as well as mass migration along a system of trunk trails are behaviours essential for survival of the colony, and the population must be able to switch from one behaviour to the other, depending on conditions. Using a mathematical model for trail following we show that subtle changes in individual behaviour can give rise to dramatic differences in the behaviour of the population, including the ability to switch from solitary movement to organized group traffic. The model incorporates biological parameters associated with the organism, the trail-marker, and the population. Ordinary differential equations are formulated for the density of the trails and for the number of individuals following trails or exploring randomly. It is assumed that the followers reinforce trails by pheromone marking, and that individuals respond to the strength of the trails by becoming more efficient followers. The model is analyzed by qualitative phase-plane methods.  相似文献   
107.
Specific quantifications of the major cellulolytic components of the Trichoderma reesei enzyme complex, i.e., endoglucanases I and III and cellobiohydrolases I and II, are described and, employing a defined mixture of these four cellulases reconstituted according to the composition of the native Trichoderma cellulase complex, used to determine the binding of each individual component onto filter paper. During substrate degradation by this enzyme mixture, the specific adsorption of each individual cellulase gradually increases and no preferential binding of one enzyme component in any particular phase of cellulose hydrolysis is found. T. reesei cellobiohydrolases I and II admixed with endoglucanases I and III represent a "full-value" cellulase system that is capable of degrading semicrystalline cellulose efficiently. In comparison with the crude Trichoderma enzyme complex, almost identical adsorption properties and similar hydrolytic efficiency are found for the reconstituted mixture. (c) 1994 John Wiley & Sons, Inc.  相似文献   
108.
Dynamic approaches to the mechanism of photosynthesis   总被引:2,自引:0,他引:2  
An account of the author's life and scientific research is presented. Two main lines of research have been pursued: (1) Studies on the physiological aspect of photosynthesis started from experiments with crops under field conditions and then extended to the study of photosynthesis in nature; and (2) studies on the mechanism of photophosphorylation and related problems which began with the measurement of quantum requirement of photophosphorylation. This work led to the discovery of the high energy state of phosphorylation and many other interesting findings. In recent years, efforts have been made to study the operation and regulation of photosynthetic apparatus with a view to link the above-mentioned lines of research together.Written at the invitation of Govindjee.  相似文献   
109.
Recently, it has been suggested (Horton et al. 1992) that aggregation of the light-harvesting a-b complex (LHC II) in vitro reflects the processes which occur in vivo during fluorescence induction and related to the major non-photochemical quenching (qE). Therefore the requirement of this chlorophyll a-b containing protein complex to produce qN was investigated by comparison of two barley mutants either lacking (chlorina f2) or depressed (chlorina104) in LHC II to the wild-type and pea leaves submitted to intermittent light (IL) and during their greening in continuous light. It was observed that qN was photoinduced in the absence of LHC II, i.e. in IL grown pea leaves and the barley mutants. Nevertheless, in these leaves qN had no (IL, peas) or little (barley mutants) inhibitory effect on the photochemical efficiency of QA reduction measured by flash dosage response curves of the chlorophyll fluorescence yield increase induced by a single turn-over flash During greening in continuous light of IL pea leaves, an inhibitory effect on QA photoreduction associated to qN developed as Photosystem II antenna size increased with LHC II synthesis. Utilizing data from the literature on connectivity between PS II units versus antenna size, the following hypothesis is put forward to explain the results summarized above. qN can occur in the core antenna or Reaction Center of a fraction of PS II units and these units will not exhibit variable fluorescence. Other PS II units are quenched indirectly through PS II-PS II exciton transfer which develops as the proportion of connected PS II units increases through LHC II synthesis.  相似文献   
110.
The influence of two enzyme solutions, differing only in the presence or absence of Macerozyme, on protoplast yield, colony formation and transient GUS (-glucuronidase) activity was studied. For all parameters tested the presence of Macerozyme during protoplast isolation had a negative influence. Using an enzyme solution without Macerozyme suspension aggregates gave up to 4.4 times higher protoplast yield and plating efficiencies were increased up to 10-fold. Further, protoplasts isolated without macerozyme showed a 5.2-fold higher GUS activity in transient gene expression. Apart from the presence of Macerozyme, longer incubation (3 compared with 1.5 h) of cell aggregates in the enzyme solution also had a negative effect on transient transformation efficiency. These data demonstrate that protoplast isolation conditions have a profound effect on transient gene expression and it is proposed that these factors will also influence stable transformation efficiency.Abbreviations CP cellulase pectolyase - CPM cellulase pectolyase Macerozyme - 2,4-d 2,4-dichlorophenoxyacetic acid  相似文献   
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