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排序方式: 共有109条查询结果,搜索用时 31 毫秒
1.
Alkaline sucrose solution was demonstrated to be a good solvent for the solubilization of water-insoluble drugs. At high concentration
and alkaline pH, sucrose solubilizes water-insoluble molecules through intramolecular conformations. Tetracyline and chloramphenicol,
when dissolved in alkaline sucrose solution, retained their bactericidal activity. Gel permeation-chromatography analysis
and atomic-force-microscopy studies confirmed the formation of sucrose-antibiotics complex. 相似文献
2.
P. Badia A. Lorenzo T. Gomez A. Bolaños 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1988,157(6):865-871
Summary Ion transport processes in the ileum of the lizard,Gallotia (=Lacerta) galloti was examined in vitro by measuring Na22 and Cl36 fluxes across short-circuited preparations.In Ringer-bicarbonate solution there was both a net sodium flux (
) and a net chloride flux (
) from mucosa to serosa. The inequality between
and short-circuit current (I
sc) suggests that part of the net sodium transport is the result of an electrically neutral transport mechanism or that another electrogenic mechanism opposite in sign is contributing to the short-circuit current.In the absence of sodium, the short-circuit current and net chloride flux were abolished. In the absence of chloride, the net sodium was reduced but not abolished and the short-circuit current was unchanged.From an analysis of the effects of the inhibitors furosemide, amiloride, disulfonic stilbene (DIDS) and acetazolamide, a plausible model was developed to explain the characteristics of these transports. It is proposed that the entry of sodium into the cell across the luminal membrane occurs by two pathways. Part occurs by the antiport Na+H+ and part by an electrogenic pathway. The entry of chloride is by the antiport Cl–HCO
3
–
.Symbols and abbreviations
DIDS 4,4
diisothiocyanatostilbene-2,2-disulfonic acid
-
G
t
tissue conductance
-
I
sc
short circuit current
-
m
mucosal
-
PD
potential difference
-
s
serosal 相似文献
3.
Salmonella typhimurium excreted the rhamnose fermentation product 1,2-propanediol not only under anaerobic conditions, but also under aerobic conditions. The absence of an aldehyde dehydrogenase enzymatic activity that oxidizes to lactate the lactaldehyde formed in the dissimilation of rhamnose raised the intracellular concentration of the aldehyde which was alternatively reduced to the excretable 1,2-propanediol by a residual propanediol oxidoreductase activity. 相似文献
4.
C. Kevers B. Bisbis F. Le Dily J. P. Billard C. Huault Th. Gaspar 《In vitro cellular & developmental biology. Plant》1995,31(2):122-126
The transfer of light-cultured green normal (N) and white habituated (HNO) sugarbeet callus to darkness reduced the growth
of N callus and improved growth and delayed necrosis in the HNO callus. The decrease of dry matter of N callus under darkness
was accompanied by a reduced content of carotenoids and by decreased CO2 fixation, which was compensated by an increased dependency on externally supplied sucrose. The levels of some organic nitrogen
compounds such as glutamate, proline, and free polyamines were not affected by transfer to darkness of N or HNO callus. Darkness
decreased ethylene emissions in both callus types. In the HNO callus, the sucrose growth dependency and the CO2 fixation were unaffected by darkness. Chlorophylls were absent both in light and darkness, whereas some carotenoids were
accumulated in the HNO callus only in dark conditions. In another connection, a significant increase of peroxidase activity,
which did not occur in the N callus, was induced by darkness in the HNO callus. A decreased content of thio-barbituric acid
(TBA)-reactive substances was measured in the HNO callus transferred to darkness, whereas an increase was noticed in the N
callus placed in the same conditions. These metabolic changes and the reduction of cellular damage in darkness revealed light-induced
stress reactions leading to necrosis and to reduced growth of HNO callus. It appeared that darkness allowed the HNO callus
to avoid the photooxidation stress. Therefore, the favorable effect of darkness on HNO growth might be explained by the suppression
of photooxidative damage due to the absence of carotenoids. The higher peroxidase activity in the HNO callus maintained in
darkness raised the problem of heme synthesis in this heterotrophic callus. 相似文献
5.
Decline in photopositive tendencies with age inDrosophila melanogaster (Diptera: Drosophilidae) 总被引:1,自引:0,他引:1
Phototaxis was measured in young, middle-aged, and oldDrosophila melanogaster flies of both sexes. The apparatus allowed us to measure the tendency to go toward light, independently of the time needed to do so; under such conditions, phototaxis is dissociated from locomotor activity. The percentage of photopositive flies decreased slightly with age (93.96, 80.17, and 78.97%, respectively, in young, middle-aged, and old flies). Results are discussed in connection with previous data for which the tendency to go toward light and the time to do so were not dissociated. 相似文献
6.
7.
Loss of function of Arabidopsis NADP‐malic enzyme 1 results in enhanced tolerance to aluminum stress
8.
Pau Rodenas Taesup Song Pitchaimuthu Sudhagar Gabriela Marzari Hyungkyu Han Laura Badia‐Bou Sixto Gimenez Francisco Fabregat‐Santiago Ivan Mora‐Sero Juan Bisquert Ungyu Paik Yong Soo Kang 《Liver Transplantation》2013,3(2):176-182
TiO2 hollow nanowires (HNWs) and nanoparticles (NPs) constitute promising architectures for QDs sensitized photoanodes for H2 generation. We sensitize these structures with CdS/CdSe quantum dots by two different methods (chemical bath deposition, CBD and succesive ionic layer adsorption and reaction, SILAR) and evaluate the performance of these photoelectrodes. Remarkable photocurrents of 4 mA·cm and 8 mA·cm?2 and hydrogen generation rates of 40 ml·cm?2·day?1 and 80 ml·cm?2·day?1 have been obtained in a three electrode configuration with sacrificial hole scavengers (Na2S and Na2SO3), for HNWs and NPs respectively, which is confirmed through gas analysis. More importantly, autonomous generation of H2 (20 ml·cm?2·day?1 corresponding to 2 mA·cm?2 photocurrent) is obtained in a two electrode configuration at short circuit under 100 mW·cm?2 illumination, clearly showing that these photoanodes can produce hydrogen without the assistance of any external bias. To the best of the authors' knowledge, this is the highest unbiased solar H2 generation rate reported for these of QDs based heterostructures. Impedance spectroscopy measurements show similar electron density of trap states below the TiO2 conduction band while the recombination resistance was higher for HNWs, consistently with the much lower surface area compared to NPs. However, the conductivity of both structures is similar, in spite of the one dimensional character of HNWs, which leaves some room for improvement of these nanowired structures. The effect of the QDs deposition method is also evaluated. Both structures show remarkable stability without any appreciable photocurrent loss after 0.5 hour of operation. The findings of this study constitute a relevant step towards the feasibility of hydrogen generation with wide bandgap semiconductors/quantum dots based heterostructures. 相似文献
9.
Approximately 100 billion liters of oil is generated per week as waste from restaurants around the country. Because of health, environmental, and economic factors, current methods of disposal are ineffective for disposal of the restaurant oil wastes. In this study we have investigated the ability of Candida bombicola to fermentatively transform the restaurant oil waste into glycolipids called sophorolipids. Batch and fed-batch studies were carried out using oil waste as the lipid feedstock in Erlenmeyer flasks and in a fermentor. Batch fermentation in a fermentor gave the highest yield of sophorolipids of 34 g L-1. Fermentation using oleic acid as control feedstock were also carried out. Batch fermentation in the fermentor using this pure fatty acid gave a highest yield of 42 g L-1. The difference in the sophorolipid yield was attributed to the fatty acid composition of restaurant oil waste. 相似文献
10.