首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   100篇
  免费   6篇
  2022年   1篇
  2021年   2篇
  2018年   2篇
  2017年   1篇
  2016年   4篇
  2015年   5篇
  2014年   4篇
  2013年   3篇
  2012年   4篇
  2011年   10篇
  2010年   3篇
  2009年   3篇
  2008年   7篇
  2007年   5篇
  2006年   4篇
  2005年   6篇
  2004年   1篇
  2003年   1篇
  2002年   4篇
  2001年   4篇
  2000年   3篇
  1999年   4篇
  1998年   2篇
  1996年   3篇
  1995年   1篇
  1994年   4篇
  1993年   4篇
  1990年   1篇
  1989年   1篇
  1988年   3篇
  1986年   2篇
  1982年   1篇
  1981年   2篇
  1977年   1篇
排序方式: 共有106条查询结果,搜索用时 15 毫秒
61.

Background

The wetlands of the North East India fall among the global hotspots of biodiversity. However, they have received very little attention with relation to their intrinsic values to human kind; therefore their conservation is hardly addressed. These wetlands are critical for the sustenance of the tribal communities.

Methods

Field research was conducted during 2003 to 2006 in seven major wetlands of four districts of Manipur state, Northeast India (viz. Imphal-East, Imphal-West, Thoubal, and Bishnupur). A total of 224 wetland-plant-collectors were interviewed for the use and economics of species using semi-structured questionnaires and interview schedules. Imphal, Bishenpur and Thoubal markets were investigated in detail for influx and consumption pattern of these plants. The collectors were also inquired for medicinal use of wetland species. Nutritive values of 21 species were analyzed in laboratory. The vouchers were collected for all the species and deposited in the CSIR-NEIST (Formerly Regional Research Laboratory), Substation, Lamphelpat, Imphal, Manipur, India.

Results

We recorded 51 edible wetland species used by indigenous people for food and medicinal purposes. Thirty eight species had high medicinal values and used in the traditional system to treat over 22 diseases. At least 27 species were traded in three markets studied (i.e. Imphal, Thoubal and Bishenpur), involving an annual turnover of 113 tons of wetland edible plants and a gross revenue of Rs. 907, 770/- (US$1 = Rs. 45/-). The Imphal market alone supplies 60% of the total business. Eighty per cent of the above mentioned species are very often used by the community. The community has a general opinion that the availability of 45% species has depleted in recent times, 15 species need consideration for conservation while another 7 species deserved immediate protection measures. The nutrient analysis showed that these species contribute to the dietary balance of tribal communities.

Conclusions

Considering the importance of wild wetland plants in local sustenance, it is suggested to protect their habitats, develop domestication protocols of selected species, and build programs for the long-term management of wetland areas by involving local people. Some medicinal plants may also be used to develop into modern medicines.
  相似文献   
62.
High level production of an extracellular cellulase-poor alkali stable xylanase has been conceded from newly isolated Bacillus pumilus SV-85S under solid state fermentation using wheat bran as a substrate. Optimization of the fermentation conditions enhanced the enzyme production to 73,000 ± 1,000 IU/g dry substrate, which was 13.8-fold higher than unoptimized conditions (5,300 IU/g). The enzyme titre was highest after 48 h of incubation at 30°C with 1:3 ratios of substrate to moistening agent using wheat bran as a carbon source. The enzyme could be produced in significant levels by using either tap water or distilled water alone as a moistening agent. An elevated production of xylanase by B. pumilus SV-85S in the presence of wheat bran, a cheap and easily available agro-residue, in shorter duration would apparently reduce the enzyme cost substantially. The enzyme was completely stable over a broad pH (5-11) range and retained 52% of its activity at a temperature of 70°C for 30 min. The desired characteristics of this enzyme together with economic production would be important for its application in paper and pulp industry.  相似文献   
63.

Background

There has been increasing interest in the use of newer, culture-independent techniques to study the airway microbiome of COPD patients. We investigated the relationships between the three common potentially pathogenic microorganisms (PPMs) Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis, as detected by quantitative PCR (qPCR), and inflammation and health status in stable patients in the London COPD cohort.

Methods

We prospectively collected sputum, serum and plasma samples for analysis of airway bacterial presence and load, and airway and systemic inflammation from 99 stable COPD patients between January 2011 and October 2012. Health status was measured with St George’s Respiratory Questionnaire and COPD Assessment Test.

Results

Airway inflammation and plasma fibrinogen, but not C-reactive protein, were greater in samples with PPM detection (p < 0.001, p = 0.049 and p = 0.261, respectively). Increasing total bacterial load was associated with increasing airway (p < 0.01) but not systemic inflammation (p > 0.05). Samples with high total bacterial loads had significantly higher airway inflammation than both samples without PPM detection and those with lower loads. Haemophilus influenzae presence was associated with significantly higher levels of airway but not systemic inflammation for all given pathogen loads (p < 0.05), and was significantly greater than with other PPMs. No association was observed between inflammation and health status (p > 0.05).

Conclusions

Airway and systemic inflammation, as measured by fibrinogen, is greater in stable COPD patients with PPMs detected using the culture-independent qPCR technique. The airway, but not systemic inflammatory response, appears to have a total pathogen-load threshold and appears attributable to Haemophilus influenzae. However, discordance between inflammation and health status was observed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0114-1) contains supplementary material, which is available to authorized users.  相似文献   
64.
Abstract

Fungal arachidonic acid (ARA)-rich oil is an important microbial oil that affects diverse physiological processes that impact normal health and chronic disease. In this article, the historic developments and technological achievements in fungal ARA-rich oil production in the past several years are reviewed. The biochemistry of ARA, ARA-rich oil synthesis and the accumulation mechanism are first introduced. Subsequently, the fermentation and downstream technologies are summarized. Furthermore, progress in the industrial production of ARA-rich oil is discussed. Finally, guidelines for future studies of fungal ARA-rich oil production are proposed in light of the current progress, challenges and trends in the field.  相似文献   
65.
The production of an alkali-stable xylanase, with dual pH optima, from haloalkalophilic Staphylococcus sp. SG-13 has been enhanced using agro-residues in submerged fermentation and a biphasic growth system. The agro-residues such as wheat bran, sugarcane bagasse, corncobs and poplar wood when used as sole carbon source, improved the xylanase yield by five-fold as compared to xylose and xylan. Staphylococcus sp. SG-13 also produced equally good amounts of xylanase when grown simply in deionized water (pH 8.0) supplemented with agro-residues as sole carbon source. In the biphasic growth system (lower layer containing agricultural residue set in agar medium with liquid medium above it), the prime substrate, wheat bran (1% w/v), resulted in maximum xylanase production of 4525 U l–1 (pH 7.5) and 4540 U l–1 (pH 9.2) at an agar: broth ratio of 4.0 after 48 h of incubation at 37 °C under static conditions. In general, the cost-effective agro-residues were found to be more suitable inducers for xylanase production over expensive substrates like xylan.  相似文献   
66.
Streptomyces cyaneus SN32 was used in this study to produce extracellular xylanase, an important industrial enzyme used in pulp and paper industry. The enzyme was purified to homogeneity by ammonium sulfate precipitation followed by anion exchange chromatography using DEAE-Sepharose column, with 43.0% yield. The enzyme was found to be a monomer of 20.5 kDa as determined by SDS gel electrophoresis and has a pI of 8.5. The optimum pH and temperature for purified xylanase activity was 6.0 and 60-65 degrees C, respectively. The half-lives of xylanase at 50 and 65 degrees C were approximately 200 and 50 min, respectively. The xylanase exhibited K(m) and V(max) values of 11.1 mg/ml and 45.45 micromol/min/mg. The 15 residue N-terminal sequence of the enzyme was found to be 87% identical up to that of endoxylanases from Steptomyces sp. Based on the zymogram analysis, sequence similarity and other characteristics, it is proposed that the purified enzyme from S. cyaneus SN32 is an endoxylanase and belongs to Group 1 xylanases (low molecular weight - basic proteins). The purified enzyme was stable for more than 20 week at 4 degrees C. Easy purification from the fermentation broth and its high stability will be highly useful for industrial application of this endoxylanase.  相似文献   
67.
Lycopene attenuates diabetes-associated cognitive decline in rats   总被引:2,自引:0,他引:2  
Kuhad A  Sethi R  Chopra K 《Life sciences》2008,83(3-4):128-134
Diabetes-induced learning and memory impairment, characterized by impaired cognitive functions and neurochemical and structural abnormalities, involve direct neuronal damage caused by intracellular glucose. The present study was designed to investigate the effect of lycopene, a potent anti-oxidant and anti-inflammatory molecule, on cognitive functions, oxidative stress and inflammation in streptozotocin (STZ)-induced diabetic rats. Cognitive functions were investigated using a spatial version of the Morris water maze test. Acetylcholinesterase activity, a marker of cholinergic dysfunction, was increased by 1.8 fold in the cerebral cortex of diabetic rats. There was about 2 fold and 2.2 fold rise in thiobarbituric acid-reactive substance levels in cerebral cortex and hippocampus of diabetic rats, respectively. Non-protein thiol levels and enzymatic activities of superoxide dismutase and catalase were decreased in both cerebral cortex and hippocampal regions of diabetic rat brain. Total nitric oxide levels in cerebral cortex and hippocampus was increased by 2.4 fold and 2 fold respectively. Serum tumor necrosis factor-alpha, an inflammatory marker, was found to increase by 8 fold in diabetic rats. Chronic treatment with lycopene (1, 2 and 4 mg/kg; p.o.) significantly and dose dependently attenuated cognitive deficit, increased acetylcholinesterase activity, oxidative-nitrosative stress and inflammation in diabetic rats. The results emphasize the involvement of oxidative-nitrosative stress and peripheral inflammation in the development of cognitive impairment in diabetic animals and point towards the therapeutic potential of lycopene in diabetes-induced learning and memory impairment.  相似文献   
68.
A full-scale study evaluating an inoculum addition to stimulate in situ bioremediation of oily-sludge-contaminated soil was conducted at an oil refinery where the indigenous population of hydrocarbon-degrading bacteria in the soil was very low (10(3) to 10(4) CFU/g of soil). A feasibility study was conducted prior to the full-scale bioremediation study. In this feasibility study, out of six treatments, the application of a bacterial consortium and nutrients resulted in maximum biodegradation of total petroleum hydrocarbon (TPH) in 120 days. Therefore, this treatment was selected for the full-scale study. In the full-scale study, plots A and B were treated with a bacterial consortium and nutrients, which resulted in 92.0 and 89.7% removal of TPH, respectively, in 1 year, compared to 14.0% removal of TPH in the control plot C. In plot A, the alkane fraction of TPH was reduced by 94.2%, the aromatic fraction of TPH was reduced by 91.9%, and NSO (nitrogen-, sulfur-, and oxygen-containing compound) and asphaltene fractions of TPH were reduced by 85.2% in 1 year. Similarly, in plot B the degradation of alkane, aromatic, and NSO plus asphaltene fractions of TPH was 95.1, 94.8, and 63.5%, respectively, in 345 days. However, in plot C, removal of alkane (17.3%), aromatic (12.9%), and NSO plus asphaltene (5.8%) fractions was much less. The population of introduced Acinetobacter baumannii strains in plots A and B was stable even after 1 year. Physical and chemical properties of the soil at the bioremediation site improved significantly in 1 year.  相似文献   
69.
The effect of nine different antibiotics (chloramphenicol, ampicillin trihydrate, kanamycin A monosulfate, neomycin sulfate, erythromycin, thiostrepton, tetracycline, apramycin sulfate and streptomycin sulfate) on growth and laccase production from Cyathus bulleri and Pycnoporus cinnabarinus has been investigated. All the antibiotics tested at a concentration of 200 mg/l affected the fungal growth, release of protein and laccase production to different extent. Inhibition in fungal growth was found to be positively correlated with increase in laccase production. Interestingly, apramycin sulfate inhibited biomass production (14.9-26.2%), nevertheless, it stimulated maximum laccase production (18.2 U/ml) in both the fungi. Increasing concentrations of apramycin sulfate enhanced laccase production from P. cinnabarinus but not from C. bulleri.  相似文献   
70.
AIM: The present study aimed at optimization of cultural and nutritional parameters for enhanced production of xylanase from Streptomyces cyaneus SN32. METHODS AND RESULTS: The xylanase production by S. cyaneus SN32 on most of the agro-residues tested in this study was more, as compared with the xylanase yield in the medium supplemented with commercial xylan. The presence of wheat bran as carbon source in the medium induced the highest production of xylanase followed by corn cob. Utilization of maize stalk, gram husk and black gram husk for microbial xylanase production has been reported first time in the present study. Among all the organic and inorganic sources of nitrogen tested in the study, peptone was found to be the best in stimulating xylanase production by S. cyaneus SN32. CONCLUSION: The production of xylanase from this thermoalkalophilic actinomycete has been enhanced 1.44-fold. To the best of our knowledge, the magnitude of enzyme yield i.e. 720 IU ml(-1) by S. cyaneus SN32 has not been reported for any other actinomycete so far. SIGNIFICANCE AND IMPACT OF STUDY: Present studies revealed that thermoalkalophilic S. cyaneus SN32, because of its simple nutritional requirements and its ability to exhibit considerably good enzyme yield, is a potent xylanase producer for its economical application in various industries.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号