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Comparison of quantitative NMR spectroscopy (QNMR) with chromatographic methods such as gas chromatography (GC) or high-pressure liquid chromatography (HPLC) for the determination of the purity of and impurities in technical grade agrochemicals, 2,4-dichlorophenoxyacetic acid (2,4-D), 1, and Dalapon sodium (sodium 2,2-dichloropropionate), 10, has revealed that QNMR is more precise and accurate than the chromatographic methods. Quantitative impurity profiling of technical grade 1 is rapid and accurate using 600 MHz (1)H NMR. Extra dispersion at the relatively high frequency allowed full assignment of the NMR spectrum of 1 and its related organic impurities in technical samples. The percentage purity of 1 was measured by the difference QNMR method, which involves summing the amounts of impurities and subtracting from 100%. Results are superior in consistency to those obtained by chromatographic methods. The percentage purity of Dalapon sodium, 10, in technical grade batches is readily obtained by (1)H QNMR, using either the difference method or the internal standard method, using dimethyl sulfone (DMSO2) internally as a reference material, that is chemically unrelated to the analyte. The latter method also allows the simultaneous identification and quantification of impurities, many of which are either not accessible to or detectable by the chromatographic methods. Uncertainty budgets for the QNMR method are presented and demonstrate that the major contributors to uncertainty lie in the weighing of the chemicals and in purity of the standard reference material prior to the QNMR experiment.  相似文献   
2.
Relaxin is a peptide hormone found in seminal plasma that has a physiological influence on sperm motility in some species. There are no reports on the effect of relaxin on acrosome reaction and utilization of glucose in boar spermatozoa. In this study, to investigate the effects of relaxin on sperm motility, acrosome reaction, and incorporation and oxidation of labeled glucose, boar spermatozoa were washed and preincubated for swim-up and then incubated (0-6 h) with 0, 20, or 40 ng/ml relaxin in mTALP medium. The results indicated that the addition of relaxin stimulated sperm motility significantly (P<0.05) during 1-4 h of incubation. The percentage of acrosome-reacted live spermatozoa was higher (P<0.05) when the spermatozoa were treated with 20 or 40 ng/ml relaxin. The rate of incorporation, and oxidation of glucose were also greater (P<0.05) in the spermatozoa incubated with relaxin compared to the control spermatozoa. The rate of incorporation and oxidation of (14)C-glucose were increased in correlation with acrosome reaction up to 4 h of incubation and then decreased in line with the increasing incubation period. In conclusion, the present study demonstrates that relaxin accelerates not only motility but also the acrosome reaction and utilization of glucose in boar spermatozoa.  相似文献   
3.
A major limitation to chickpea grown on residual soil moisture after the harvest of rice in the High Barind Tract (HBT) of Bangladesh is acidic surface soil. A diagnostic trial conducted in the 2001/02 season showed that Mo was limiting growth and yield of chickpea. Multilocational on‐farm trials in the 2002/03 season established that Mo applied to the soil at 500 g ha–1 improved nodulation and plant growth and resulted in grain‐yield responses of 58%–173%. In addition, we tested an application method suitable for resource‐poor farmers where Mo and Rhizobium were added in the seed‐priming process. Multilocational trials in farmers' fields in 2003/04 confirmed that this was as effective as soil application of Mo, giving yield responses of 37%–90%. In each of 2004/05 and 2005/06 seasons, 50 farmers implemented on‐farm evaluations of adding Mo + Rhizobium in the priming solution in operational scale plots (666 m2) across the HBT. Mean responses of up to 50%, compared to priming in water only, were obtained. These results suggest that the severe N deficiency of chickpea commonly observed in the HBT can be effectively alleviated by applying Mo and Rhizobium inoculum through a simple low‐cost technology within the scope of resource‐poor farmers.  相似文献   
4.
The research work was conducted with 10 rice germplasm during T. Aman (wet season), 2004, at Bangladesh Rice Research Institute, Gazipur, to assess the different lodging concerned parameters and their interrelationships. A great extent of diversity among aromatic rice genotypes was observed in respect to canopy architecture and lodging related characters. Minimum seedling height was 30 cm for BR39 and the maximum was 47 cm for Hatisail. Variations were found in the cultivars regarding penultimate and flag leaf angles and dimensions of both the leaves. Maximum plant height was recorded to be 153 cm in Baoi jhak and the minimum was 100 cm in BR28. The longest panicle was observed in Nizersail (27 cm) and shortest in Hatisail (21 cm). The range of culm diameter was 4.0–4.7 mm and culm thickness was 0.40–0.51 mm. Rice cultivars varied for bending moment from 812 g · cm (BR28) to 2263 g · cm (Doiar guro). Lodging index was at a minimum 2.7 in BR28 and a maximum 11.28 in Sugandha-1. Plant height exhibited positive correlation with panicle exertion and internode lengths, and hence lodging index. Lodging index was found to have a negative relationship with breaking strength. In path analysis, bending moment projected highest positive direct effect on lodging index.  相似文献   
5.
ABSTRACT

Many forest reserves in Bangladesh have been converted to protected areas (PAs) to conserve the forests resources from further depletion. This study has investigated if such initiatives have improved the state of biodiversity of these PAs amid tremendous anthropogenic pressure on forest resources. We have assessed the phytosociological attributes of the PAs in the country through a case study at Kaptai National Park (KNP) and compared the attributes with those of the adjacent areas and of the tropical forests across the world. We have identified 52 species belonging to 45 genera and 28 families. The most dominant species in KNP was Dipterocarpus spp. and the adjacent area was dominated by Tectona grandis. Unexpectedly, the Shannon-Wiener index of KNP has dropped down from 2.98 in 2000 to 0.90 in 2014. However, in terms of relative density, relative dominance, and relative frequency, KNP was better than the adjacent areas. In contrast, the mean Shannon-Wiener index in KNP (0.90) was smaller than that in the tropical countries (2.99). We recommend strengthening effective comanagement of PAs and enabling nonforestry income generation activities for the forest-dependent people so that the biodiversity of the PAs can be enriched while people’s livelihoods are ensured.  相似文献   
6.
Modified atmosphere packaging (MAP) is commercially used to increase the shelf life of packaged produce by reducing the produce respiration rate, delaying senescence, and inhibiting the growth of many spoilage organisms, ultimately increasing product shelf life. MAP systems typically optimize O(2) levels to achieve these effects while preventing anaerobic fermentation but fail to optimize CO(2) concentrations. Altering film permselectivity (i.e., beta, which is the ratio of CO(2)/O(2) permeation coefficients) could be utilized to concurrently optimize levels of both CO(2) and O(2) in MAP systems. We investigated the effect of modifying film permselectivity on the equilibrium gas composition of a model MAP produce system packaged in containers incorporating modified poly(ethylene) ionomer films with CO(2)/O(2) permselectivites between 4-5 and 0.8-1.3. To compare empirical to calculated data of the effect of permselectivity on the equilibrium gas composition of the MAP produce system, a mathematical model commonly used to optimize MAP of respiring produce was applied. The calculated gas composition agreed with observed values, using empirical respiration data from fresh cut apples as a test system and permeability data from tested and theoretical films. The results suggest that packaging films with CO(2)/O(2) permselectivities lower than those commercially available (<3) would further optimize O(2) and CO(2) concentration in MAP of respiring produce, particularly highly respiring and minimally processed produce.  相似文献   
7.
A bioavailability and pharmacokinetics study of doxycycline was carried out on 30 healthy ostriches after a single intravenous (IV), intramuscular (IM) and oral dose of 15 mg/kg body weight. The plasma doxycycline concentration was determined by HPLC/UV at 0 (pretreatment), 0.08, 0.25, 0.5 1, 2, 4, 6, 8, 12, 24 and 48 h after administration. The plasma concentration-time curves were examined using non-compartmental methods based on the statistical moment theory for only the higher dose. After IV administration, the elimination half-life (t1/2β), mean residence time (MRT), volume of distribution at the steady-state (Vss), volume of distribution (Vdarea) and total body clearance (ClB) were 7.67 ± 0.62 h, 6.68 ± 0.86 h, 0.86 ± 0.16 l/kg, 1.67 ± 0.52 l/kg and 2.51 ± 0.63 ml/min/kg, respectively. After IM and oral dosing, the mean peak plasma concentrations (Cmax) were 1.34 ± 0.33 and 0.30 ± 0.04 µg/ml, respectively, which were achieved at a post-administration time (tmax) of 0.75 ± 0.18, 3.03 ± 0.48 h, respectively. The t1/2β, Vdarea and ClB after IM administration were 25.02 ± 3.98 h, 23.99 ± 3.4 l/kg and 12.14 ± 1.71 ml/min/kg, respectively and 19.25 ± 2.53 h, 61.49 ± 7 l/kg and 40.19 ± 3.79 ml/min/kg after oral administration, respectively. The absolute bioavailability (F) of doxycycline was 5.03 and 17.52% after oral and IM administration, respectively. These results show that the dose data from other animals particularly mammals cannot be extrapolated to ostriches. Therefore, based on these results along with those reported in the literature, further studies on the pharmacokinetic/pharmacodynamic, in vitro minimum inhibitory concentration values and clinical applications of doxycycline in ostriches are required.  相似文献   
8.
Multiple spawnings are special reproductive tactics that many fish evolved to obtain different types of direct and/or indirect spawning benefits. This has led to two pertinent questions: (a) what types of benefit does a commercially important fish provide during multiple induced spawnings annually? and (b) is there any trade‐off between traits during these spawnings? To address these questions, the present study was carried out with two separate experiments during two spawning events of an Indian major carp (Catla catla) to assess: (a) male's spawning performances and (b) female's spawning performances. The male's spawning data revealed that they produced significantly higher amount of milt and hatchlings during the first spawning, while they significantly reduced hatchling deformation rate, enhanced offspring survival rate and enlarged offspring body size during the second spawning. The female's spawning information unveiled no significant differences in total egg weight, hatching rate and hatchling deformation rate between the first and second spawning. However, females had significantly higher offspring survival rate during the first spawning and enhanced offspring body size during the second spawning. Interestingly, the analysis of trait associations revealed that males allocated energy with a trade‐off between milt weight and offspring survival rate, whereas females showed a trade‐off between hatching rate and offspring survival rate. Thus, the study provides some important information for carp breeders and associated stakeholders to know which spawning season is preferable for the higher production of eggs, milt and good quality larvae.  相似文献   
9.
Concerning the requirements of effective drug candidates to combat against high rising multidrug resistant pathogens, we isolated three new linear lipopeptides, gageostatins A–C (1–3), consisting of hepta-peptides and new 3-β-hydroxy fatty acids from the fermentation broth of a marine-derived bacterium Bacillus subtilis. Their structures were elucidated by analyzing a combination of extensive 1D, 2D NMR spectroscopic data and high resolution ESIMS data. Fatty acids, namely 3-β-hydroxy-11-methyltridecanoic and 3-β-hydroxy-9,11-dimethyltridecanoic acids were characterized in lipopeptides 1 and 2, respectively, whereas an unsaturated fatty acid (E)-7,9-dimethylundec-2-enoic acid was assigned in 3. The 3R configuration of the stereocenter of 3-β-hydroxy fatty acids in 1 and 2 was established by Mosher’s MTPA method. The absolute stereochemistry of amino acid residues in 1–3 was ascertained by acid hydrolysis followed by Marfey’s derivatization studies. Gageostatins 1–3 exhibited good antifungal activities with MICs values of 4–32 µg/mL when tested against pathogenic fungi (R. solani, B. cinerea and C. acutatum) and moderate antibacterial activity against bacteria (B. subtilis, S. aeureus, S. typhi and P. aeruginosa) with MICs values of 8–64 µg/mL. Futhermore, gageostatins 1–3 displayed cytotoxicity against six human cancer cell lines with GI50 values of 4.6–19.6 µg/mL. It is also noteworthy that mixed compounds 1+2 displayed better antifungal and cytotoxic activities than individuals.  相似文献   
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