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Whitbread Anthony Blair Graeme Naklang Kunnika Lefroy Rod Wonprasaid Sodchol Konboon Yothin Suriya-arunroj Duangjai 《Plant and Soil》1999,207(1):29-36
The maintenance of soil organic matter (SOM) and the balancing of nutrient flows into and out of the rainfed rice cropping
systems in Northeast Thailand is of paramount importance to arresting the decline in soil fertility and crop yields. A system
where small applications of leaf litters from locally grown trees are applied annually to rice paddy soils prior to transplanting
is described. The annual application of 1500 kg/ha of Cajanus cajan, Acacia auriculiformis, Phyllanthus taxodifolius and Samanea
saman for five seasons resulted in increases in rice grain yield of 48, 35, 32 and 23% above the no-leaf litter control, respectively.
Average annual nutrient inputs from the leaf litters, in kg/ha, ranged from 62.7 N, 3.9 P, 17.9 K, and 3.5 S for Cajanus cajan
to 24.5 N, 1.5 P, 8.1 K and 2.0 S for Acacia auriculiformis. Nutrient balances, determined by the difference between the inputs
(fertiliser and added leaf litters) and outputs (grain and straw) indicated net positive N and P balances of up to 457 and
60 kg/ha. respectively, after five seasons of leaf litter applications. Sulfur and potassium balances resulted in net deficits
of up to −3 and −52 kg S and K/ha, respectively, where no leaf litter was applied and rice straw was removed following harvest.
Calculated apparent nutrient recoveries reflected the decomposition rate of the added residues and were highest for P and
K, reflecting their higher soil residual value than mobile nutrients such as N and S. Sustainable farming systems will require
that crop yields are stable through the maintenance of soil fertility and the balance of nutrients in the system.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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A demonstration of athermal effects of continuous microwave irradiation on the growth and antibiotic sensitivity of Pseudomonas aeruginosa PAO1 下载免费PDF全文
Stress, caused by exposure to microwaves (2.45 GHz) at constant temperature (37 ± 0.5°C), alters the growth profile of Pseudomonas aeruginosa PAO1. In the absence of microwave treatment a simple, highly reproducible growth curve was observed over 24 h or more. Microwave treatment caused no reduction in growth during the first 6 h, but at a later stage (>12 h) the growth was markedly different to the controls. Secondary growth, typical of the presence of persisters clearly became apparent, as judged by both the dissolved oxygen and the cell density profiles. These treated cells showed distinct morphological changes, but on regrowth these cells reverted to normal. The microwave induced persisters were subject to antibiotic challenge (tobramycin) and showed increased sensitivity when compared to the unstressed planktonic cells. This is in marked contrast to antibiotic induced persisters which show increased resistance. This provides evidence for both a nonthermal effect of microwaves and a previously undescribed route to a novel form of antibiotic susceptible persister cells. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:37–44, 2017 相似文献
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With the objective of reducing maternal and neonatal mortality, the Safe Motherhood Program was implemented in Nepal in 1997. It was launched as a priority programme during the ninth five-year plan period, 1997-2002, with the aim of increasing women's access to health care and raising their status. This paper examines the association of access to health services and women's status with utilization of prenatal, delivery, and postnatal care during the plan period. The 1996 Nepal Family Health Survey and the 2001 Nepal Demographic and Health Survey data were pooled and the likelihood of women's using maternal health care was examined in 2001 in comparison with 1996. Multiple logistic regression analysis indicates that the utilization of maternal health services increased over the period. Programme interventions such as outreach worker's visits, radio programmes on maternal health, maternal health information disseminated through various mass media sources and raising women's status through education were able to explain the observed change in utilization. Health worker visits and educational status of women showed a large association, but radio programmes and other mass media information were only partially successful in increasing use of maternal health services. Socioeconomic and demographic variables such as household economic status, number of living children and place of residence showed stronger association with use of maternal health services then did intervention programmes. 相似文献
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The performance of a resazurin chromogenic agar plate with a combined disc method for rapid screening of extended‐spectrum‐β‐lactamases,AmpC β‐lactamases and co‐β‐lactamases in Enterobacteriaceae 下载免费PDF全文
Yothin Teethaisong Katie Evans Ismini Nakouti Kanokwan Tiamyom James R. Ketudat‐Cairns Glyn Hobbs Griangsak Eumkeb 《Microbiology and immunology》2017,61(8):297-304
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Yothin Teethaisong Nongluk Autarkool Kittipot Sirichaiwetchakoon Pongrit Krubphachaya Sajeera Kupittayanant Griangsak Eumkeb 《Journal of biomedical science》2014,21(1)
Background
Ampicillin-resistant S. aureus (ARSA) now poses a serious problem for hospitalized patients, and their care providers. Plant-derived antibacterial that can reverse the resistance to well-tried agents which have lost their original effectiveness are the research objectives of far reaching importance. To this aim, the present study investigated antibacterial and synergistic activities of Stephania suberosa extracts (SSE) against ARSA when used singly and in combination with ampicillin.Results
The majority chemical compounds of SSE were alkaloid (526.27 ± 47.27 mg/1 g of dried extract). The Minimum inhibitory concentration (MICs) for ampicillin and SSE against all ARSA strains were >512 μg/ml and 4 mg/ml, respectively. Checkerboard assay revealed synergistic activity in the combination of ampicillin (0.15 μg/ml) and SSE (2 mg/ml) at fractional inhibitory concentration index (FICI) <0.5. The killing curve assay had confirmed that the viability of ARSA was dramatically reduced from 5x105 cfu/ml to 103 cfu/ml within 6 h after exposure to SSE (2 mg/ml) plus ampicillin (0.15 μg/ml) combination. Electron microscopic study clearly revealed that these ARSA cells treated with this combination caused marked morphological damage, peptidoglycan and cytoplasmic membrane damage, and average cell areas significant smaller than control. Obviously, Immunofluorescence staining and confocal microscopic images confirmed that the peptidoglycan of these cells were undoubtedly disrupted by this combination. Furthermore, the CM permeability of ARSA was also increased by this combination. Enzyme assay demonstrated that SSE had an inhibitory activity against β-lactamase in concentrations manner.Conclusions
So, these findings provide evidence that SSE has the high potential to reverse bacterial resistance to originate traditional drug susceptibility of it and may relate to three modes of actions of SSE: (1) inhibits peptidoglycan synthesis, resulting in morphological damage, (2) inhibits β-lactamases activity, and (3) increases CM permeability. It is widely recognized that many types of drugs are derived from alkaloids. So, this SSE offers the prominent potential to develop a novel adjunct phytopharmaceutical to ampicillin for the treatment of ARSA. Further active ingredients study, toxicity of it, and the synergistic effect on blood and tissue should be performed and confirmed in an animal test or in humans. 相似文献
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