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61.
Humic acids (HA) contribute to soil fertility because of their chemical, physical, and biological properties. The origin of HAs in soils has puzzled scientists for decades, and what HAs are and what their origin is remain unclear. The isolation of HAs in plants, which have characteristics close to soil HAs, suggests the probable origin of soil-HA is the preservation of plant tissue, indicating biochemical origin. In this paper HA from maize plant at different stages of maturity is isolated, from which it was found that the evolution of this fraction depends on and is derived from cell wall formation. Evidence was also found that HA was above all composed of lignin and cutin residues, and was characterized by low surface area. After 8 months of incubation in both mineral-artificial and natural soils, humic acid isolated form maize plant could be recovered intact.  相似文献   
62.
63.
After isolation from different doughs and sourdoughs, 177 strains of lactic acid bacteria were screened at the phenotypic level for exopolysaccharide production on media containing different carbohydrate sources. Two exopolysaccharide-producing lactic acid bacteria (Lactobacillus curvatus 69B2 and Leuconostoc lactis 95A) were selected through quantitative analysis on solid media containing sucrose and yeast extract. The PCR detection of homopolysaccharide (gtf and lev) and heteropolysaccharide (epsA, epsB, epsD and epsE, and epsEFG) genes showed different distributions within species and strains of the lactic acid bacteria studied. Moreover, in some strains both homopolysaccharide and heteropolysaccharide genes were detected. Proton nuclear magnetic resonance spectra suggest that Lactobacillus curvatus 69B2 and Leuconostoc lactis 95A produced the same exopolysaccharide, which was constituted by a single repeating glucopyranosyl unit linked by an α-(1→6) glycosidic bond in a dextran-type carbohydrate. Microbial growth, acidification, and viscoelastic properties of sourdoughs obtained by exopolysaccharide-producing and nonproducing lactic acid bacterial strains were evaluated. Sourdough obtained after 15 h at 30°C with exopolysaccharide-producing lactic acid bacteria reached higher total titratable acidity as well as elastic and dissipative modulus curves with respect to the starter not producing exopolysaccharide, but they showed similar levels of pH and microbial growth. On increasing the fermentation time, no difference in the viscoelastic properties of exopolysaccharide-producing and nonproducing samples was observed. This study suggests that dextran-producing Leuconostoc lactis 95A and Lactobacillus curvatus 69B2 can be employed to prepare sourdough, and this would be particularly useful to improve the quality of baked goods while avoiding the use of commercially available hydrocolloids as texturizing additives.  相似文献   
64.
Rhodiola rosea has been used for centuries in the traditional medicine to stimulate nervous system, to enhance physical and mental performance and to treat fatigue. It is known that administration of Rhodiola rosea extract elicits antidepressant activity, but the mechanism of action still remains unclear. Evidence from animal models and human studies show that nicotine reduces symptoms of depression and that nicotine cessation induces depressive-like symptoms. We investigated the effects of Rhodiola rosea on nicotine withdrawal signs. Nicotine dependence was induced by subcutaneous nicotine injection (2mg/kg, four times daily) for 14 days. Another group of animals treated with nicotine (for 14 days) and successively with Rhodiola rosea extract was co-administered with selective 5-HT receptorial antagonist WAY 100635 (1mg/kg). After nicotine withdrawal animals were evaluated for behavioural parameters (locomotor activity, abstinence signs, marble burying test), diencephalic serotonin metabolism and serotonin receptor-1A expression. Results show a significant increase of 5-HT content in N treated with R. rosea, with a significant increase of serotonin receptor 1A, suggesting an involvement of serotonin in beneficial effects of R. rosea on suffering produced by nicotine withdrawal.  相似文献   
65.

Background and Aim

Altered expression of microRNAs (miRNAs) hallmarks many cancer types. The study of the associations of miRNA expression profile and cancer phenotype could help identify the links between deregulation of miRNA expression and oncogenic pathways.

Methods

Expression profiling of 866 human miRNAs in 19 colorectal and 17 pancreatic cancers and in matched adjacent normal tissues was investigated. Classical paired t-test and random forest analyses were applied to identify miRNAs associated with tissue-specific tumors. Network analysis based on a computational approach to mine associations between cancer types and miRNAs was performed.

Results

The merge between the two statistical methods used to intersect the miRNAs differentially expressed in colon and pancreatic cancers allowed the identification of cancer-specific miRNA alterations. By miRNA-network analysis, tissue-specific patterns of miRNA deregulation were traced: the driving miRNAs were miR-195, miR-1280, miR-140-3p and miR-1246 in colorectal tumors, and miR-103, miR-23a and miR-15b in pancreatic cancers.

Conclusion

MiRNA expression profiles may identify cancer-specific signatures and potentially useful biomarkers for the diagnosis of tissue specific cancers. miRNA-network analysis help identify altered miRNA regulatory networks that could play a role in tumor pathogenesis.  相似文献   
66.
The interplay between anatomical connectivity and dynamics in neural networks plays a key role in the functional properties of the brain and in the associated connectivity changes induced by neural diseases. However, a detailed experimental investigation of this interplay at both cellular and population scales in the living brain is limited by accessibility. Alternatively, to investigate the basic operational principles with morphological, electrophysiological and computational methods, the activity emerging from large in vitro networks of primary neurons organized with imposed topologies can be studied. Here, we validated the use of a new bio-printing approach, which effectively maintains the topology of hippocampal cultures in vitro and investigated, by patch-clamp and MEA electrophysiology, the emerging functional properties of these grid-confined networks. In spite of differences in the organization of physical connectivity, our bio-patterned grid networks retained the key properties of synaptic transmission, short-term plasticity and overall network activity with respect to random networks. Interestingly, the imposed grid topology resulted in a reinforcement of functional connections along orthogonal directions, shorter connectivity links and a greatly increased spiking probability in response to focal stimulation. These results clearly demonstrate that reliable functional studies can nowadays be performed on large neuronal networks in the presence of sustained changes in the physical network connectivity.  相似文献   
67.
Global warming will lead to earlier beginnings and prolongation of growing seasons in temperate regions and will have pronounced effects on phenology and life-history adaptation in many species. These changes were not easy to simulate for actual phenologies because of the rudimentary temporal (season) and spatial (regional) resolution of climate model projections. We investigate the effect of climate change on the regional incidence of a pest insect with nearly worldwide distribution and very high potential for adaptation to season length and temperature--the Codling Moth, Cydia pomonella. Seasonal and regional climate change signals were downscaled to the hourly temporal scale of a pest phenology model and the spatial scale of pest habitats using a stochastic weather generator operating at daily scale in combination with a re-sampling approach for simulation of hourly weather data. Under future conditions of increased temperatures (2045-2074), the present risk of below 20% for a pronounced second generation (peak larval emergence) in Switzerland will increase to 70-100%. The risk of an additional third generation will increase from presently 0-2% to 100%. We identified a significant two-week shift to earlier dates in phenological stages, such as overwintering adult flight. The relative extent (magnitude) of first generation pupae and all later stages will significantly increase. The presence of first generation pupae and later stages will be prolonged. A significant decrease in the length of overlap of first and second generation larval emergence was identified. Such shifts in phenology may induce changes in life-history traits regulating the life cycle. An accordingly life-history adaptation in photoperiodic diapause induction to shorter day-length is expected and would thereby even more increase the risk of an additional generation. With respect to Codling Moth management, the shifts in phenology and voltinism projected here will require adaptations of plant protection strategies to maintain their sustainability.  相似文献   
68.

Background

Ovarian cancer remains a leading cause of death in women and development of new therapies is essential. Second mitochondria derived activator of caspase (SMAC) has been described to sensitize for apoptosis. We have explored the pro-apoptotic activity of LBW242, a mimic of SMAC/DIABLO, on ovarian cancer cell lines (A2780 cells and its chemoresistant derivative A2780/ADR, SKOV3 and HEY cells) and in primary ovarian cancer cells. The effects of LBW242 on ovarian cancer cell lines and primary ovarian cancer cells was determined by cell proliferation, apoptosis and biochemical assays.

Principal Findings

LBW242 added alone elicited only a moderate pro-apoptotic effect; however, it strongly synergizes with tumor necrosis factor-related apoptosis inducing ligand (TRAIL) or anticancer drugs in inducing apoptosis of both ovarian cancer cell lines and primary ovarian cancer cells. Mechanistic studies show that LBW242-induced apoptosis in ovarian cancer cells is associated with activation of caspase-8. In line with this mechanism, c-FLIP overexpression inhibits LBW242-mediated apoptosis.

Conclusion

LBW242 sensitizes ovarian cancer cells to the antitumor effects of TRAIL and anticancer drugs commonly used in clinic. These observations suggest that the SMAC/DIABLO mimic LBW242 could be of value for the development of experimental strategies for treatment of ovarian cancer.  相似文献   
69.

Objectives

The main objective of the present study was to estimate the uptake to quality indicators that reflect the current evidence-based recommendations and guidelines.

Methods

A retrospective review of medical records of patients admitted to two hospitals in the South of Italy was conducted. For the purposes of the analysis, a sets of quality indicators has been used from the Joint Commission on Accreditation of Hospital Organizations and Centers for Medicare & Medicaid Services. Four areas of care were selected: acute myocardial infarction (AMI), heart failure (HF), pneumonia (PN), and surgical care improvement project (SCIP). Frequency or median was calculated, as appropriate, for each indicator. A composite score was calculated to estimate the overall performance for each area of care.

Results

A total of 1772 medical records were reviewed. The adherence rates showed a wide-ranging variability among the selected indicators. The use of aspirin and angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) for AMI, the use of ACEI or ARB for HF, the use of appropriate thromboembolism prophylaxis and appropriate hair removal for surgical patients almost approached optimal adherence. At the other extreme, rates regarding adherence to smoking-cessation counseling in AMI and HF patients, discharge instructions in HF patients, and influenza and pneumococcal vaccination in pneumonia patients were noticeably intangible. Overall, the recommended processes of care among eligible patients were provided in 70% for AMI, in 32.4% for HF, in 46.4% for PN, and in 46% for SCIP.

Conclusions

The results show that there is still substantial work that lies ahead on the way to improve the uptake to evidence-based processes of care. Improvement initiatives should be focused more on domains of healthcare than on specific conditions, especially on the area of preventive care.  相似文献   
70.

Background

Asthma guidelines suggest that therapy can be reduced once asthma is controlled. Despite these recommendations, asthmatic patients are seldom stepped down in clinical practice, and questions remain about when and how to reduce asthma therapy. The purpose of the present study was to evaluate lung function and asthma control in patients who were stepped down from the highest recommended dose of inhaled corticosteroid/long acting β2 agonist combination therapy.

Methods

This was a prospective, randomised, controlled, two-arm parallel group study. Asthmatic patients who were fully controlled with a high daily dose (1000/100 μg) of fluticasone/salmeterol were randomly assigned to 6 months of open-label treatment with either 500/100 μg fluticasone/salmeterol Diskus daily or 400/24 μg extrafine beclomethasone/formoterol pMDI daily. The primary outcome was the change in morning peak expiratory flow (PEF) values between baseline and the end of treatment. The secondary outcomes included asthma control and exacerbation frequency.

Results

Four hundred twenty-two patients were included in the analysis. The PEF values remained above 95% of the predicted values throughout the study. The end-study morning PEF rates showed equivalence between the groups (difference between means, 2.49 L/min; 95% CI, -13.43 to 18.42). No changes from baseline were detected in PEF and forced expiratory volume in 1 second measured at the clinics, in the symptom scores or in the use of rescue medication. Asthma control was maintained in 95.2% of the patients at 6 months. No significant differences between the groups were detected in any other parameter, including exacerbation frequency and adverse events.

Conclusions

Stepping down patients whose asthma is controlled with the highest recommended dose of fluticasone/salmeterol to either 500/100 μg fluticasone/salmeterol daily or 400/24 μg extra-fine beclomethasone/formoterol daily provides comparable maintenance of lung function and asthma control.

Trial registration

clinicaltrials.gov NCT00497237  相似文献   
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