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排序方式: 共有285条查询结果,搜索用时 15 毫秒
1.
Mat Rasol Awang Hassan Hamdani Mutaat Mohd. Shukri Mahmud Wan Badrin Wan Husain Tajuddin Osman Khomsaton Abu Bakar Asmahwati Kassim Zal U''yun Wan Mahmud Ishak ManafTamikazu Kume Shoji Hashimoto 《Radiation Physics and Chemistry》1993,42(4-6):611-616
In solid state fermentation, Pleurotus sajor-caju has been found to be able to degrade at least 30% oil palm empty Fruit Bunch (EFB) fibre leaving 70 % useful materials. Conditions under which fermentation carried out were investigated. It was found that, in the temperature range between 25– 28 °C, relative ph between 6–8, moisture between 60–70 % and medium composition of CaCO3: rice bran 2 %: 5 % were the optimum conditions. The results showed in fermented products that, there were substantial reduction in cellulosic component such as Crude Fiber (CF, 18 %); Acid Detergent Fibre (ADF, 45 %), Neutral Detergent Fibre (NDF, 61 %) and Acid Detergent Lignin (ADL, 14 %). However, Crude Protein (CP, 10%) increased resulted from single cell protein enrichment of mycelial microbial mass. The mass reductions of substrate in fermentation process corresponds to the CO2 released during fermentation. Hence, attributable to the decreased in content of CF, ADF, NDF, and ADL. The digestibility study has also been carried out to determine the useful level of this product to ruminant. Aflatoxin content was detected low in both the initial substrates and products. Based on nutritional value and low content of aflatoxin, the product is useful as a source of roughage to ruminant. 相似文献
2.
Kessler BM Tortorella D Altun M Kisselev AF Fiebiger E Hekking BG Ploegh HL Overkleeft HS 《Chemistry & biology》2001,8(9):913-929
BACKGROUND: The 26S proteasome is responsible for most cytosolic proteolysis, and is an important protease in major histocompatibility complex class I-mediated antigen presentation. Constitutively expressed proteasomes from mammalian sources possess three distinct catalytically active species, beta1, beta2 and beta5, which are replaced in the gamma-interferon-inducible immunoproteasome by a different set of catalytic subunits, beta1i, beta2i and beta5i, respectively. Based on preferred cleavage of short fluorogenic peptide substrates, activities of the proteasome have been assigned to individual subunits and classified as 'chymotryptic-like' (beta5), 'tryptic-like' (beta2) and 'peptidyl-glutamyl peptide hydrolyzing' (beta1). Studies with protein substrates indicate a far more complicated, less strict cleavage preference. We reasoned that inhibitors of extended size would give insight into the extent of overlapping substrate specificity of the individual activities and subunits. RESULTS: A new class of proteasome inhibitors, considerably extended in comparison with the commonly used fluorescent substrates and peptide-based inhibitors, has been prepared. Application of the safety catch resin allowed the generation of the target compounds using a solid phase protocol. Evaluation of the new compounds revealed a set of highly potent proteasome inhibitors that target all individual active subunits with comparable affinity, unlike the other inhibitors described to date. Modification of the most active compound, adamantane-acetyl-(6-aminohexanoyl)(3)-(leucinyl)(3)-vinyl-(methyl)-sulfone (AdaAhx(3)L(3)VS), itself capable of proteasome inhibition in living cells, afforded a new set of radio- and affinity labels. CONCLUSIONS: N-terminal extension of peptide vinyl sulfones has a profound influence on both their efficiency and selectivity as proteasome inhibitors. Such extensions greatly enhance inhibition and largely obliterate selectivity towards the individual catalytic activities. We conclude that for the interaction with larger substrates, there appears to be less discrimination of different substrate sequences for the catalytic activities than is normally assumed based on the use of small peptide-based substrates and inhibitors. The compounds described here are readily accessible synthetically, and are more potent inhibitors in living cells than their shorter peptide vinyl sulfone counterparts. 相似文献
3.
T. Kilic T. Dirmenci F. Satil G. Bilsel T. Kocagoz M. Altun A. C. Goren 《Chemistry of Natural Compounds》2005,41(3):276-279
The fatty acid composition of seed extracts of Salvia bracteata, S. aethiopis, and S. candidissima ssp. candidissima were analyzed by GC/MS. The main compound of S. bracteata, S. aethiopis, and S. candidissima ssp. candissima was found to be 9,12-octadecenoic acid at 64.3%, 73.4%, and 20.8%, respectively. The seed extracts of S. bracteata showed activity against S. aureus E. coli, M. smegmatis, and C. albicans with MIC values of 1.1, 0.5, 1.1, and 1.1 mg/mL, respectively, while the seeds extract of S. aethiopis showed activity against the same microorganisms with MIC values of 2.2, 2.2, 1.1, and 1.1 mg/mL, respectively. However, the seed extract of S. candidissima ssp. candidissima showed activity only against M. smegmatis with a MIC value of 0.25 mg/mL.__________Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 223–225, No. 3, May–June 2005. 相似文献
4.
A
modulated dsc study on the in situ polymerization of cyclic butylene terephthalate
oligomers 总被引:1,自引:0,他引:1
Z. A. Mohd Ishak P. P. Shang J. Karger-Kocsis 《Journal of Thermal Analysis and Calorimetry》2006,84(3):637-641
The polymerization of a cyclic butylene terephthalate
(CBT) oligomer was studied as a function of temperature (T=200
and 260°C, respectively) by modulated DSC (MDSC). The first heating was
followed by cooling after various holding times (5, 15 and 30 min) prior to
the second heating which ended always at T=260°C.
This allowed us to study the crystallization and melting behavior of the resulting
polybutylene terephthalate (PBT), as well. In contrary to the usual belief,
the CBT polymerization is exothermic and the related process is superimposed
to that of the CBT melting. The melting behavior of the PBT was affected by
the polymerization mode (performed below or above the melting temperature
of the PBT product) of the CBT. Annealing above the melting temperature of
PBT yielded a product featuring double melting. This was attributed to the
presence of crystallites with different degrees of perfection. The crystals
perfection which occurred via recrystallization/remelting was manifested by
a pronounced exothermic peak in the non-reversing trace. 相似文献
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8.
Motasem Y. D. Alazaiza Su Kong Ngien Mustafa M. Bob Samira A. Kamaruddin Wan Mohd Faizal Ishak 《Transport in Porous Media》2017,117(1):103-123
Double porosity is a substantial microstructure characteristic in a wide range of geomaterials. It is a natural phenomenon that can be found in many types of soil, and it can result from biological, chemical or mechanical damage. In this paper, the influence of macro-pores on dense non-aqueous phase liquid (DNAPL) migration in double-porosity medium was investigated using light transmission visualization technique. Three experiments were carried out in two-dimensional flow chambers filled with a double-porosity medium composed of a mixture of local sand and sintered kaolin clay spheres arranged in a periodic manner. In each experiment, a different volumetric fraction of macro-pores and micropores was used. Tetrachloroethylene (PCE) was used to simulate DNAPL, and it was dyed using Oil-Red-O for better visualization. A predetermined amount of PCE was injected into the flow chambers and this amount was re-calculated using image analysis. A very strong correlation was found between the PCE amount injected and the amount calculated from image analysis in each experiment. The experiment was repeated by filling the flow chamber with silica sand to represent single-porosity medium. The results show that the macro-pores have a considerable effect on the PCE migration in double-porosity soil as the PCE movement was the fastest in the third experiment which contained the largest macro-pores volume. The accuracy of the method was validated using statistical analysis. The results show a slight difference between the means of the three experiments, indicating that the method is viable for monitoring NAPL migration in double-porosity medium under different volumetric fractions of macro-pores and micropores. 相似文献
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