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61.
Fibroblast growth factors (FGFs) are involved in paracrine control of follicle development. It was previously demonstrated that FGF10 decreases estradiol (E(2)) secretion in granulosa cell culture and that theca cell FGF10 mRNA expression is decreased in healthy follicles from abattoir ovaries. The main objectives of this study were to evaluate FGF10 and FGFR2b mRNA expression during follicular development in vivo, to evaluate the effect of FGF10 on follicle growth using Bos taurus taurus cows as a model, and to gain more insight into the mechanisms through which FGF10 inhibits steroidogenesis. Messenger RNA encoding both FGF10 and FGFR2b (main FGF10 receptor) was significantly more expressed in subordinate follicles (SFs) than in dominant follicles (DFs). The intrafollicular injection of FGF10 into the largest growing follicle at 7-8?mm in diameter interrupted the DF growth in a dose-dependent manner (11±0.4, 8.3±1 and 5.9±0.3?mm for 0, 0.1, and 1?μg/ml FGF10, respectively, at 72?h after treatment; P<0.05). In a third experiment, follicles were obtained 24?h after FGF10 (1?μg/ml) or PBS treatment through ovariectomy. In theca cells, FGF10 treatment did not affect mRNA encoding steroidogenic enzymes, LHCGR and IGFBPs, but significantly upregulated FGF10 mRNA expression. The expression of CYP19A1 mRNA in granulosa cells was downregulated by FGF10 treatment, which was accompanied by a 50-fold decrease in E(2) production, and decreased cyclin D2 mRNA. These results have shown that FGF10 and its receptor FGFR2b are more expressed in SFs and provide solid in vivo evidence that FGF10 acts as an important regulator of follicular growth in cattle.  相似文献   
62.
Food fraud is an intentional act for economic gain. It poses a risk to food integrity, the economy, public health and consumers’ ethics. Seafood is one commodity which has endured extensive fraudulent activity owing to its increasing consumer demand, resource limitations, high value and complex supply chains. It is essential that these fraudulent opportunities are revealed, the risk is evaluated and countermeasures for mitigation are assigned. This can be achieved through mapping of the seafood supply chains and identifying the vulnerability analysis critical control points (VACCP), which can be exposed, infiltrated and exploited for fraudulent activity. This research systematically maps the seafood supply chain for three key commodities: finfish, shellfish and crustaceans in the United Kingdom. Each chain is comprised of multiple stakeholders across numerous countries producing a diverse range of products distributed globally. For each supply chain the prospect of fraud, with reference to species substitution, fishery substitution, illegal, unreported and unregulated substitution, species adulteration, chain of custody abuse, catch method fraud, undeclared product extension, modern day slavery and animal welfare, has been identified and evaluated. This mapping of the fraudulent opportunities within the supply chains provides a foundation to rank known and emerging risks and to develop a proactive mitigation plan which assigns control measures and responsibility where vulnerabilities exist. Further intelligence gathering and management of VACCPs of the seafood supply chains may deter currently unknown or unexposed fraudulent opportunities.  相似文献   
63.
The aim of this study was to investigate the effect of freeze‐drying, hot air‐drying and vacuum‐drying at 70, 90 and 110 °C, on dried lemon pomace polyphenols and antioxidant capacity. The total phenolic content and antioxidant capacity were higher in lemon pomace dried by hot air or under vacuum than those dried by freeze‐drying and increased as the temperature increased. The highest total flavonoid content was recorded in the pomace dried under vacuum at 70 and 90 °C. Lemon pomace dried by freeze‐drying had the highest neohesperidin content, whereas pomace dried under vacuum at 70 °C had the highest rutin and p‐coumaric acid content. The highest gallic acid content was recorded in the pomace dried by hot air at 110 °C. The results of this study indicate that drying technique should be carefully selected according to the bioactive compounds aimed to be extracted.  相似文献   
64.
Many dairy cows succumb to disease after calving. Disease risk may be affected by the cows' social environment and ability to perform maternal behaviors. In nature, cattle isolate from others and find seclusion to give birth; these behaviors may be limited in indoor group pens and could potentially affect the cows' ability to cope. The aim was to determine whether stocking density and a physical blind in prepartum bedded-pack group pens affected physiological biomarkers, disease risk, and hygiene of peripartum dairy cows. A randomized complete block designed with a 2 × 2 factorial arrangement of treatments was used. Approximately 3 wk before calving, 374 cows (primiparous = 127; multiparous = 247) were assigned randomly to 1 of 4 treatment pens with the following 2 factors: (1) high versus low stocking density (7.7 to 12.9 m2 vs. 15.4 to 25.8 m2 lying space per cow), and (2) presence or absence of a blind. The blind was created using plastic road barriers and plywood, a steel gate, and shade cloth. After calving, cows were moved into a freestall pen and milked 3 times per day. Blood was sampled on the day of enrollment (baseline; ?24 d) and approximately ?14, ?7, 3, 7, 10, and 14 d relative to calving, to measure inflammatory (haptoglobin) and metabolic (nonesterified fatty acids and β-hydroxybutyrate) biomarkers. β-Hydroxybutyrate (≥1.2 mmol/L) was used to diagnose subclinical ketosis. Vaginal discharge was scored 3, 7, 10, and 14 d after calving, to diagnose metritis (none, mild, or severe). Hygiene was scored on ?24, ?14, and ?7 d before calving. Before calving, haptoglobin was lower in pens with a blind. After calving, cows in pens with low stocking density before calving tended to be at greater odds of being diagnosed with metritis. Cows were more likely to have poorer hygiene scores in high stocking density pens. No treatment effects were detected for pre- and postpartum nonesterified fatty acids, β-hydroxybutyrate, postpartum haptoglobin, or subclinical ketosis. Results suggest that the provision of a blind and lower stocking density may be beneficial for reducing inflammation before calving. However, low prepartum stocking density might increase the odds of metritis after calving. Although the reason for this paradox is unclear, the effects of prepartum stocking density may require further exploration.  相似文献   
65.
碳水化合物的色谱分析对很多行业的研究来说都是非常重要的工作。例如.食品中单糖与二糖的定性定量,由于复杂糖类.糖醇、人造甜味剂与盐皆可形成复杂基质.使分析变得困难;制药行业通常使用简单或复杂的糖类或糖衍生物基质作为起始药物.通过对药物配方中的这些化合物进行分析,可以为生产提供所需要的信息;  相似文献   
66.
67.
Bioaccumulation of perfluoroalkyl sulfonates, perfluorocarboxylates, and 2-(N-ethylperfluorooctane sulfonamido) acetic acid (N-EtFOSAA) from laboratory-spiked and contaminated field sediments was assessed using the freshwater oligochaete, Lumbriculus variegatus. Semistatic batch experiments were conducted to monitor the biological uptake of these perfluorochemicals (PFCs) over 56 days. The elimination of PFCs was measured as the loss of PFCs in L. variegatus exposed to PFC-spiked sediment for 28 days and then transferred to clean sediment. The resultant data suggest that PFCs in sediments are readily bioavailable and that bioaccumulation from sediments does not continually increase with increasing perfluorocarbon chain length. Perfluorooctane sulfonate (PFOS) and perfluorononanoate were the most bioaccumulative PFCs, as measured by laboratory-based estimated steady-state biota sediment accumulation factors (BSAFs) and BSAFs measured using contaminated field sediments. Elimination rate constants for perfluoroalkyl sulfonates and perfluorocaroboxylates were generally smaller than those previously measured for other organic contaminants. Last, a PFOS precursor, N-EtFOSAA, accumulated in the worm tissues and appeared to undergo biotransformation to PFOS and other PFOS precursors. This suggests that N-EtFOSAA, which has been detected in sediments and sludge often at levels exceeding PFOS, may contribute to the bioaccumulation of PFOS in aquatic organisms.  相似文献   
68.
Iron(VI) and iron(V) oxidation of thiocyanate   总被引:1,自引:0,他引:1  
Thiocyanate (SCN-) is used in many industrial processes and is commonly found in industrial and mining waste-waters. The removal of SCN- is required because of its toxic effects. The oxidation of thiocyanate (SCN-) by environmentally friendly oxidants, Fe(VI) and Fe(V), has been studied anaerobically using stopped-flow and premix pulse radiolysis techniques. The stoichiometry with Fe(VI) was determined to be 4HFeO(4-) + SCN(-) + 5H2O-->4Fe(OH)3 + SO4(2-) + CNO(-) + O2 + 2OH-. The rate law for the oxidation of SCN- by Fe(VI) was found to be -d[Fe(VI)]/dt = k11([H+]/([H+] + Ka,HFeO4)) [Fe(VI)][SCN-] where k11 = 2.04 +/- 0.04 x 10(3) M-1 s-1 and pKa,HFeO4 = 7.33. A mechanism is proposed that agrees with the observed reaction stoichiometry and rate law. The rate of oxidation of SCN- by Fe(V) was approximately 3 orders of magnitude faster than Fe(VI). The higher reactivity of Fe(V) with SCN- indicates that oxidations by Fe(VI) may be enhanced in the presence of appropriate one-electron-reducing agents. The results suggest that the effective removal of SCN- can be achieved by Fe(VI) and Fe(V).  相似文献   
69.
The application of the photo-Fenton process to the treatment of saline wastewater contaminated with hydrocarbons is investigated. Aqueous saline solutions containing raw gasoline were used as a model oil-field-produced water. The dependence on concentrations of the following reagents has been appropriately evaluated: hydrogen peroxide (100-200 mM), iron ions (0.5-1 mM), and sodium chloride (200-2000 ppm). The reactions were monitored by measurement of the absorption spectra and total organic carbon (TOC). Experimental results demonstrate that the photo-Fenton process is feasible for the treatment of wastewaters containing hydrocarbons, even in the presence of high concentrations of salt. The effect of the salt in this process is described through a series of reactions. A simple feedforward neural network model was found to correlate well the observed data for the degradation process.  相似文献   
70.
Experiments were performed to assess the reduction of Campylobacter spp. and Escherichia coli in commercial broiler carcasses by postchill dip applications of acidified sodium chlorite. Carcass rinses were collected before the inside-outside-bird washer (IOBW), post-IOBW, postchill, and after the postchill application of acidified sodium chlorite. Prevalence and counts of Campylobacter spp. and E. coli were determined. The mean values for Campylobacter spp. and E. coli counts differed significantly at sampling sites. The IOBW reduced the bacterial counts significantly in only one experiment. The chiller reduced Campylobacter counts significantly in both experiments but failed to significantly reduce the counts of E. coli in one experiment. No major reduction in the prevalence after enrichment for Campylobacter spp. was detected post-IOBW or postchill. However, a significant reduction in Campylobacter spp. and in E. coli counts and Campylobacter spp. prevalence was seen after the postchill application of acidified sodium chlorite. These results demonstrate that the antimicrobial effect of acidified sodium chlorite applied postchill may be used to significantly reduce Campylobacter spp. and E. coli in commercial broiler carcasses. Postchill systems may eventually be used in different applications, such as mist, spray, or bath, which could be applied closer to the final stages in processing.  相似文献   
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