首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Results from pilot tests of microspherical aluminochromium KDI-M catalyst mixed with IM-2201 in a large-scale unit (Nizhnekamskneftekhim) for iso-butane dehydrogenation are discussed. Compared to KDI catalyst, its modified analogue KDI-M is more active and selective; the optimized grain-size composition and mechanical strength ensures higher yields of iso-butylene and longer nonstop operation (up to 400 days) of the reactor unit.  相似文献   

2.
The influence of the following factors on the reactivity CRI and hot strength CSR in industrial coking is studied: eliminating bituminous coal from the coal batch; considerably increasing the coking periods; and significantly reducing the ash content of the batch. Batch composition such that the coke quality meets the needs of export customers (including requirements regarding CRI and CSR) is identified. Sharp deterioration in CRI and CSR is seen when the batch includes coal with high ash basicity and coal concentrate that is heavily contaminated with intermediate products.  相似文献   

3.
An effective S-adenosylmethionine and glutathione enriching yeast mutant of Candida utilis CCTCC M 209298 was first screened from plates containing 0.5 g/L of DL-ethionine by complex mutagenesis with UV and γ-ray in this study. Medium components optimization for enhanced co-production of S-adenosylmethionine and glutathione by C. utilis CCTCC M 209298 was further carried out using response surface methodology. The significant factors influencing S-adenosylmethionine and glutathione co-production were selected by Plackett-Burman design as sucrose, KH2PO4 and L-methionine, and Box-Behnken design was applied for further optimization studies. Based on these approaches, the optimized concentrations on medium components for higher co-production of S-adenosylmethionine and glutathione were sucrose 35.4 g/L, (NH4)2SO4 10 g/L, KH2PO4 12.3 g/L, MgSO4·7H2O, 0.05 g/L, CaCl2 0.05 g/L and L-methionine 4.6 g/L. The medium optimization by response surface methodology led to a total production of 589.3 mg/L on S-adenosylmethionine and glutathione, which was 2.4-fold increased compared with the medium without optimization.  相似文献   

4.
5.
Two sets of experimental data characterizing the chemical composition of coal ash, its flow temperature t c, and the CSR and CRI values of the coke from such coal are analyzed. The results indicate that the content of four oxides (SiO2, Fe2O3, CaO, and Na2O) may be used to predict t c and also CSR and CRI in mathematical models. Models of the form y = a(I 4) b , where y = t c, CSR, or CRI and I 4 = SiO2/(Fe2O3 + CaO + Na2O), adequately describe the experimental data within the range considered.  相似文献   

6.
7.
8.
Aim of the present study was to identify the chemical composition of Origanum vulgare L. essential oil and to investigate its effect on the biochemical behavior of the yeast Yarrowia lipolytica. Twenty-three compounds were identified by GC–MS analysis, representing the 92.3% (w/w) of the total essential oil of the plant. Carvacrol (56.3%) and thymol (16.4%) were the major components. Additionally, shake-flask cultivations of Y. lipolytica were performed, with various essential oil additions (0.05–2 mL/L of medium) on glycerol-based media. Growth was affected even at low concentrations (0.05 mL/L), while in higher essential oil concentrations, strong inhibition phenomena were observed. A tolerance-threshold concentration for the strain was hence established at 0.15 mL/L of oil. Furthermore, the presence of the essential oil in the culture medium resulted in changes in the composition of the intra-cellular lipids of the yeast. Specifically, oil addition to nitrogen-limited cultures to a level >0.15 mL/L caused a substantial increase in the percentage of saturated fatty acids (C16:0 and C18:0) in the lipid composition of the yeast Y. lipolytica.  相似文献   

9.
Pheromones in social insects play a key role in the regulation of group homoeostasis. It is well-established that parasites can modify hormone signaling of their host, but less is known about the effect of parasites on pheromone signaling in insect societies. We, thus, tested in honey bees (Apis mellifera) the effect of the widespread parasite Nosema spp. on the production of ethyl oleate (EO), the only identified primer pheromone in honey bee workers. Since environmental stressors like pesticides also can weaken honey bees, we also analyzed the effect of imidacloprid, a neonicotinoid widely used in agriculture, on EO production. We show that, contrary to imidacloprid, Nosema spp. significantly altered EO production. In addition, the level of Nosema infection was correlated positively with the level of EO production. Since EO is involved in the regulation of division of labor among workers, our result suggests that the changes in EO signaling induced by parasitism have the potential to disturb the colony homoeostasis.  相似文献   

10.
Terpenes are the largest group of phytochemicals that exhibit diverse functions in mediating antagonistic and beneficial interactions in, and among, organisms. For many years the abundance and distribution of terpenoid compounds in plants have benefitted both nature and human civilization. Jatropha species, belonging to the family Euphorbiaceae, are a rich source of terpenoid compounds. Among the terpenes, diterpenoid compounds have dominated the research area in Jatropha species with respect to their novel chemical structures and medicinal values. The present review describes the chemistry and biological activities of an array of Jatropha diterpenes. The diterpenes isolated from Jatropha species belongs to rhamnofolane, daphnane, lathyrane, tigliane, dinorditerpene, deoxy preussomerin and pimarane skeletal structures. Among the 68 diterpenes collated in this review, the biological activity of compounds varied distinctly—the majority of the diterpenes exhibited cytotoxic, antitumor and antimicrobial activities in vitro. To name a few, jatrophone, spruceanol and jatrophatrione exhibited antitumor properties against P338 lymphocytic leukemia and japodagrol against KB carcinoma cells. Whereas, curcusone B exhibited anti-invasive effects against cholangiocarcinoma cells. The phorbol esters (Jatropha factor C1C6) and Jatropherol exhibited insect deterrent/cytotoxic properties. Many diterpenes (jatrophalactam, faveline derivatives, multifolone, curcusone, jatrophone derivatives etc.) showed in-vitro cytotoxic activity, while japodagrin, jatrogrossidione derivatives and jatropholone derivatives exhibited antimicrobial activities. Jatropha diterpenoids having a wide spectrum of bioactivity could form lead compounds or could be used as templates for the synthesis of new compounds with better biological activity for utilization in the pharmaceutical industries.  相似文献   

11.
A systematic collection of Jatropha curcas germplasm was carried out from five distinct ecogeographic zones of peninsular India in 2008. This involved recording passport data, documentation of important plant traits in situ, ecogeographic parameters and assessment of variability in 82 accessions. Extraction of oil was done by the Soxhlet method which gave an average yield of 38%. Oil content of collected accessions was determined by nuclear magnetic resonance and Soxhlet extraction. Oil variability ranged from 45.5% in JC-8 to 11.5% in JC-30. The level of unsaturated fatty acid ranged from 85% in JC-57 to 75.5% in JC-10. Saturated fatty acids ranged from 24% in JC-43 to 15% in JC-54, the oxidative stability index was highest at 2.1 in JC-30 and lowest at 0.68 in JC-17. The seed weight was greatest in JC-8 and the lowest in JC-30. This paper provides information that will facilitate the selection of promising accessions for genetic enhancement of Jatropha germplasm through conventional breeding.  相似文献   

12.
Sheath blight and brown spot disease of rice caused by Rhizoctonia solani and Bipolaris oryzae causes significant yield loss in rice production worldwide. The present study was undertaken to examine the effect of two essential oils (EOs) from Lippia geminata and Cymbopogon jwarancusa on in vitro growth and sporulation of these two pathogens. The fungal radial growth was inhibited at very low concentration (25 ppm) of the EOs. Similarly, fungal spore production was also inhibited up to ≥80% at 500 ppm of EOs. However, fungal sporulation was completely retarded at 1,000 ppm of L. geminata EO. Very low oil concentrations (10 ppm) accelerated the radial growth (0–5 mm) and spore germination (3.5–8.5%) of the pathogens. At higher oil concentrations, the mycelial growth and spore productions were completely inhibited. The IC50 value of the EO of C. jwarancusa was 365.45 and 336.74 ppm and for L. geminata, it was 420.16 and 481.47 ppm against B. oryzae and R. solani, respectively. GC–MS analysis of the oils showed 54.36% piperitone and 30.86% α-phellandrene as major compounds in C. jwarancusa whereas 25.9% geranial and 14.6% neral in L. geminata oil. Essential oils from Lippia geminata and Cymbopogon jwarancusa appear to be good candidates for the in vitro control of these two rice pathogens and can be successfully utilized in management strategies of pathogens in appropriate formulation.  相似文献   

13.
The effect of the reducing power on the reduction of methyl-2-chlorobenzoylformate was evaluated by using carbon substrates with different reducing powers. Glucose, sorbitol, and gluconate regenerated 2, 3, and 1 NAD(P)H during its conversion to pyruvate, respectively. When sorbitol was used as the carbon substrate, complete conversion was achieved in 8 h while it took 12 h and 19 h when glucose and gluconate were used, respectively. The enantiomeric excess (ee) value was 96.7% when sorbitol was used.  相似文献   

14.
Biological pesticides based on nucleopolyhedroviruses (NPVs) can provide an effective and environmentally benign alternative to synthetic chemicals. On some crops, however, the efficacy and persistence of NPVs is known to be reduced by plant specific factors. The present study investigated the efficacy of Helicoverpa armigera NPV (HearNPV) for control of H. armigera larvae, and showed that chickpea reduced the infectivity of virus occlusion bodies (OBs) exposed to the leaf surface of chickpea for at least 1 h. The degree of inactivation was greater on chickpea than that previously reported on cotton, and the mode of action is different from that of cotton. The effect was observed for larvae that consumed OBs on chickpea leaves, but it also occurred when OBs were removed after exposure to plants and inoculated onto artificial diet, indicating that inhibition was leaf surface-related and permanent. Despite their profuse exudation from trichomes on chickpea leaves and their low pH, organic acids—primarily oxalic and malic acid—caused no inhibition. When HearNPV was incubated with biochanin A and sissotrin, however, two minor constituents of chickpea leaf extracts, OB activity was reduced significantly. These two isoflavonoids increased in concentration by up to 3 times within 1 h of spraying the virus suspension onto the plants and also when spraying only the carrier, indicating induction was in response to spraying and not a specific response to the HearNPV. Although inactivation by the isoflavonoids did not account completely for the level of effect recorded on whole plants, this work constitutes evidence for a novel mechanism of NPV inactivation in legumes. Expanding the use of biological pesticides on legume crops will be dependent upon the development of suitable formulations for OBs to overcome plant secondary chemical effects.  相似文献   

15.
The present study was performed to investigate the effect of dietary conjugated linoleic acid (CLA) on the growth performance, immune parameters and disease resistance to Aeromonas hydrophila of juvenile Jian carp. A total of 900 juvenile Jian carp (10.71 ± 0.02 g) were randomly allocated into six groups of each three replicates, feeding isonitrogenous (35% crude protein) and isolipidic (7.8% crude fat) diets containing graded amounts of CLA (0, 0.5, 0.8, 1.4, 1.7, and 2.0%) for 60 days. After a 60-day growth test, a challenge trial was conducted by intraperitoneal injection of Aeromonas hydrophila to determine the effect of CLA on disease resistance of juvenile Jian carp. The results showed that diets incorporated with a proportion of up to 2.0% CLA without effect on weight gain, feed intake, and feed conversion ratio, but improved immune parameters and disease resistance of juvenile Jian carp. The dietary CLA level of optimal disease resistance to Aeromonas hydrophila was estimated to be 1.7% in juvenile Jian carp using broken-line analysis.  相似文献   

16.
Growth profile of predominantly Pseudomonas species was studied using wastewater containing phenol and m-cresol, as single and multi component systems in an internal loop airlift bioreactor (ILALR). The species utilized for the study was isolated from a wastewater treatment plant. The reactor was operated at both lower and higher hydraulic retention time (HRTs), 4.1 h and 8.3 h, respectively. The inlet phenol and concentration was varied between 100 and 800 mg/L with 800 mg/L as shock loading concentration for an HRT of 8.3 h. For 4.1 h HRT, the concentration was varied 100 and 500 mg/L using 500 mg/L as a shock loading concentration. The study showed complete degradation of both phenol and m-cresol, when present individually at an HRT of 8.3 h with an enriched biomass output. The specific growth rate of the culture at various phenol and m-cresol concentrations was fitted to a Monod model. The biokinetics value showed good potential of Pseudomonas species employing the internal loop air lift bioreactor in utilizing high strength phenolics containing wastewater. Culture growth profile with both phenol and m-cresol as mixtures also showed decreased lag times with complete utilization of the phenolics.  相似文献   

17.
The trans fatty acid (TFA) patterns in the fats of ruminant meat and dairy products differ from those found in other (processed) fats. We have evaluated different TFA isomers in human breast milk as an indicator of dietary intake of ruminant and dairy fats of different origins. Breast milk samples were collected 1 month postpartum from 310 mothers participating in the KOALA Birth Cohort Study (The Netherlands). The study participants had different lifestyles and consumed different amounts of dairy products. Fatty acid methyl esters were determined by GC-FID and the data were evaluated by principal component analysis (PCA), ANOVA/Post Hoc test and linear regression analysis. The two major principal components were (1) 18:1 trans-isomers and (2) markers of dairy fat including 15:0, 17:0, 11(trans)18:1 and 9(cis),11(trans)18:2 (CLA). Despite similar total TFA values, the 9(trans)18:1/11(trans)18:1-ratio and the 10(trans)18:1/11(trans)18:1-ratio were significantly lower in milk from mothers with high dairy fat intake (40–76 g/day: 0.91 ± 0.48, P < 0.05) compared to low dairy fat intake (0–10 g/day: 1.59 ± 0.48), and lower with strict organic meat and dairy use (>90% organic: 0.92 ± 0.46, P < 0.05) compared to conventional origin of meat and dairy (1.40 ± 0.61). Similar results were obtained for the 10(trans)18:1/11(trans)18:1-ratio. We conclude that both ratios are indicators of different intake of TFA from ruminant and dairy origin relative to other (including industrial) sources.  相似文献   

18.
The accumulation of benzo[a]pyrene as a coal pyrolysis product in the soil cover of Chelyabinsk and its surroundings, which are characterized by a high concentration of industrial enterprises and power plants within the confines of the city, was evaluated. The concentrations of this carcinogenic substance in various soils were found higher than the maximum permissible concentration (20 μg/kg).  相似文献   

19.
A new device for measuring the pore characteristics of adsorbents is developed for fast measurement and convenient sample handling. The proposed device utilizes a quartz crystal resonator capable of detecting the change of mass loading in nanogram scale. The measured material is coated on the electrode surface of the resonator, and the change of resonant frequency of the resonator at different pressures of adsorbate gas is converted into the adsorbed amount used in the computation of the adsorption surface area and pore size. For the performance evaluation of the device, alumina and activated carbon are tested with the adsorbate, i-butane. The experimental results show that the proposed device gives comparable measurements with some deviation to the reference values of the adsorption characteristics. It is proved that the device is relatively simple and requires short measurement time and the mild condition of sample handling.  相似文献   

20.
The role of extracellular fatty acids in the interference between two algae, Chlorella vulgaris Beijerink and Pseudokirchneriella subcapitata (Korshikov) Hindak, was assessed by the co-cultivation of the two selected strains, as well as by the chemical analysis of exudates from the culture media of single strain cultures. The effect of culture age and phosphate limitation was evaluated. The experiments showed that the composition and amount of fatty acids, released by C. vulgaris and by P. subcapitata, both in a batch and in a continuous monoculture, depend on the culture age and on the phosphate concentration in the culture medium. We also found that the amount of chlorellin generated in the two algae co-culture increased and was almost exclusively constituted by a mixture of C18 fatty acids. By using the evaluated concentrations of these fatty acids, an artificial chlorellin was prepared. The toxicity of this mixture to P. subcapitata appears to be similar to that of the natural chlorellin. For both algae, a stimulation of growth was observed at low concentrations of the natural chlorellin, whereas higher concentrations produced inhibitory effects on both species. However, P. subcapitata was much more sensitive than C. vulgaris. By using some of these new experimental results, two new mathematical models have been used to describe the toxicity of chlorellin to C. vulgaris and to the interference between C. vulgaris and P. subcapitata, respectively.  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