排序方式： 共有45条查询结果，搜索用时 15 毫秒
21.
22.
壤和堆肥中四环素类抗生素的检测方法优化及其在土壤中的降解研究 总被引：2，自引：0，他引：2
在对土霉素（OTC）、四环素（TC）和金霉素（CTC）3 种四环素类抗生素的高效液相色谱（HPLC）检测分析方法以及在土壤和堆肥中的提取方法进行改进和优化的基础上,采用该方法进行了 3 种抗生素在土壤中的降解试验。结果表明,选用 Agilent Eclipse XDB-C8（4.6150 mm,5 m）色谱柱,以 0.01 mol/L草酸/乙腈/甲醇（79/10.5/10.5,v/v/v）为流动相,紫外检测波长 268 nm,流速 1.0 mL/min,进样量 5 L,采用外标法定量,可使 3 种四环素类抗生素在 20 min 内全部洗脱并达到基线分离; 在 0~10 mg/L 范围内,抗生素浓度与峰面积呈显著的线性关系,相关系数（r）均 0.999。土壤和堆肥样品中的 OTC、TC 和 CTC可用1 mol/L NaCl/0.5 mol/L 草酸/乙醇（25/25/50,v/v/v）混合溶液提取,其回收率在 76.0%~92.5% 之间。加入到土壤中的抗生素在 25℃下避光培养 49 d 后,在壤土和红土中的降解率分别是 67%~72% 和 36%~46%,对应的半衰期分别为 2630 d 和 4675 d,说明抗生素在壤土中比红土中容易降解。此外,3种抗生素在壤土中的半衰期没有显著性差异,而在红土中 CTC 和 TC 的降解速率显著高于 OTC。 相似文献
23.
24.
25.
MIN‐SU LEE AH‐RA LEE MI‐AE JUNG IN‐HYE LEE JI‐HYE CHOI HYUN‐WOO CHUNG SOON‐WUK JEONG SANG‐SOEP NAHM KI‐DONG EOM 《Veterinary radiology & ultrasound》2010,51(6):670-673
We evaluated the whole body distribution of 2‐deoxy‐2‐[18F]fluoro‐d ‐glucose (18F‐FDG) in seven beagle dogs using positron emission tomography/computed tomography. The mean and maximum standard uptake values (SUV) for various tissues were computed. The SUV of the aortic blood pool was 0.65±0.19. Moderate uptake was present in brain (3.40±1.01). Mild uptake was present in orbital muscles, soft palate, laryngeal and pharyngeal region, mandibular salivary gland, myocardium, liver, pancreas, kidney, and intestine. 18F‐FDG uptake would be normally higher in these tissues because of normal physiologic activity. Mean and maximum SUV values of the eye, skeletal muscle, bone tissue, spleen, adrenal gland, stomach, tongue, gall bladder, and lung were similar to or lower than that of the aortic blood pool. These data provide a normal baseline for comparing pathologic 18F‐FDG uptake. 相似文献
26.
广州及其附近十字花科蔬菜花叶病毒的鉴定 总被引：1，自引：0，他引：1
广州郊区、新会县荷塘乡及南海县等重要蔬菜栽培区域的无菁(Brassica juncea(L.) Coss.)、芥菜(B.juncea(L.) Coss.)、白菜(B.chinensis L.)、菜心(B.sp)、蘿卜(Raphanus sativus L.)和大白菜(土名绍菜)(B.pekinensis(Lour.) Rupr.)等十字花科蔬菜普遍而严重地感染一种花叶病。 相似文献
27.
28.
本研究探讨了核移植前对受体卵子进行激活、细胞融合开始时间及供体受精卵细胞周期调节对核移植卵体外发育的影响。其结果显示核移植前对受体卵子激活组的细胞融合率与对照组没有差异 ,但重组胚胎的卵裂率、8～ 16细胞期胚胎及囊胚的发育率比对照组明显提高 ;核移植前激活的受体卵子分别在卵子体外成熟开始的第30h和 4 5h与供体细胞进行细胞融合 ,结果 ,30h组的细胞融合率和卵裂率与 4 5h组没有差异 ,但发育到 8～ 16细胞期及囊胚的发育率均比 4 5h的高 ;将供体受精卵用诺考达唑 (Nocodazole)处理后 ,进行核移植的结果 ,处理组的细胞融合率、卵裂率、发育到 8～ 16细胞期和囊胚的发育率与对照组无差异 相似文献
29.
Adiposity, fatty acid composition, and delta-9 desaturase activity during growth in beef cattle 总被引：3，自引：1，他引：3
Stephen B. SMITH David K. LUNT Ki Y. CHUNG Chang B. CHOI Ron K. TUME Meiji ZEMBAYASHI 《Animal Science Journal》2006,77(5):478-486
Oleic acid (18:1n‐9) is the most abundant fatty acid in bovine adipose tissue. Because most of the lipid in bovine muscle is contributed by intramuscular adipocytes, oleic acid also is the predominant fatty acid in beef. In many species, the concentration of oleic acid in adipose tissue is dictated by the average concentration of oleic acid in the diet, but in ruminant species such as beef cattle, oleic acid is hydrogenated largely to stearic acid by ruminal microorganisms. In these species, the concentration of oleic acid in adipose tissue is dependent upon the activity of Δ9 desaturase, encoded by the stearoyl coenzyme A desaturase (SCD) gene. Expression of the SCD gene is essential for bovine preadipocyte differentiation, and desaturase gene expression and catalytic activity increase dramatically as adipose tissue mass increases after weaning. Feeding a hay‐based diet to American Wagyu steers to a typical Japanese bodyweight endpoint (650 kg) markedly stimulated desaturase enzyme activity as well as the accumulation of both oleic acid and intramuscular lipid, but the increase in oleic acid and intramuscular lipid was much less in hay‐fed Angus steers. Increasing the concentration of oleic acid improves the palatability and healthiness of beef, and Korean Hanwoo and Japanese Black (and American Wagyu) seem especially well adapted to accumulate oleic acid in their adipose tissue. 相似文献
30.
Jin Young CHUNG Dae Young YOO Wooseok IM Jung Hoon CHOI Sun Shin YI Hwa Young YOUN In Koo HWANG Je Kyung SEONG Yeo Sung YOON 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(2):167-173
In the current study, we investigated whether electroacupuncture (EA) can inhibit pathological reductions in neurogenesis. Zucker diabetic fatty (ZDF) rats at 7 weeks of age were anesthetized with zoletil, and sham-acupuncture or EA at the Zusanli (ST36) and Baihui (GV20) acupoints was administered once a day for 5 weeks. In the ZDF group that received sham-EA (ZDF-Sham group), the blood glucose level was significantly increased together with age as compared to the control littermates [Zucker lean control (ZLC) rat]. In contrast, proliferating cells and differentiated neuroblasts were significantly decreased in the ZDF-Sham group compared to the ZLC group. Although EA treatment decreased blood glucose levels, this was not statistically significant when compared to blood glucose levels changes in the ZDF-Sham group. However, proliferating cells and differentiated neuroblasts were significantly increased with EA in ZDF rats as compared to those in the ZDF-Sham group.
Brain-derived neurotrophic factor (BDNF) levels were significantly decreased in hippocampal homogenates of ZDF-Sham group compared to those in the ZLC group. The EA treatment significantly increased the BDNF levels compared to those in the ZDF-Sham group, and BDNF levels in this group were similar to those in the ZLC group. These results suggest that EA at ST36 and GV20 can ameliorate the reductions in proliferating cells and differentiated neuroblasts in the dentate gyrus induced by type-2 diabetes without significantly reducing blood glucose levels with increasing BDNF levels. 相似文献