不同氧气浓度对绵羊体外受精胚胎凋亡的影响

为了研究培养环境中的氧气浓度对绵羊体外受精胚胎发育的影响。比较了低氧环境(5%O2)和高氧环境(20%O2)中绵羊体外受精胚胎的发育能力和凋亡发生情况,同时利用Real-time PCR技术检测这两种氧气浓度下绵羊体外受精胚胎中凋亡相关基因Bax和Bcl-2的表达水平。结果表明：在这两种氧气浓度下发育的绵羊体外受精胚胎,细胞凋亡信号都起始于16-细胞期,且在胚胎各发育阶段发生凋亡的比率没有明显差异,但低氧环境组的囊胚发育率和囊胚细胞数都显著高于高氧环境组的（分别为45.9%、134;14.6%、106,P＜0.05）,且其囊胚细胞的凋亡指数也显著低于高氧环境组（分别为0.053、0.066,P＜0.05）;PCR的研究结果表明：不论是高氧环境还是低氧环境,在绵羊体外受精胚胎的各阶段都能检测到Bax和Bcl-2的表达。而且在囊胚阶段,低氧环境下的Bcl-2基因表达量明显高于高氧环境下的。低氧环境可以抑制绵羊胚胎细胞的凋亡,更有利于绵羊胚胎的发育。     

基于土壤张力的土壤湿度传感器的设计与标定

为实时准确监测土壤的水吸力,基于土壤张力计电阻应变原理,研制开发一款结构简单、价格低廉的土壤张力传感器。传感器标定与误差分析结果表明,该传感器的精度与灵敏度较高,能够满足设计要求。     

柴胡对蟾蜍离体心脏功能活动影响的研究

[目的]观察不同浓度的柴胡水煮液对离体蟾蜍心脏活动的影响。[方法]采用斯氏离体蛙心灌流方法,分别以不同浓度的柴胡水煮液对离体的蟾蜍心脏进行灌流,经BL-420E生物机能实验系统记录离体蟾蜍心脏的收缩活动。[结果]0.009 g/ml的柴胡水煮液对离体蟾蜍心脏收缩振幅和心率影响均不明显（P〉0.05;P〉0.05）;而0.018 g/ml和0.180 g/ml的柴胡溶液对离体蟾蜍心脏收缩振幅和心率均具有降低与减慢的作用,影响显著（P〈0.01;P〈0.01）;尤其0.180 g/ml柴胡溶液对离体蟾蜍心脏的心肌收缩力的抑制作用更为明显,甚至导致心脏停止跳动。[结论]柴胡水煮液可抑制蟾蜍离体心脏的心肌收缩力,对心率有明显的减慢作用。     

不同干燥预处理对杨木应拉木孔隙结构的影响

采用CO<,2>超临界干燥、冷冻干燥和常规干燥对杨木应拉木和对应木进行干燥预处理,通过干燥前后试样的形变和吸附等温线,比较不同干燥预处理对杨木应拉木孔隙结构的影响,为定量表征应拉木的微观孔隙结构提供理论依据.结果表明:经CO<,2>超临界干燥的杨木应拉木具有完好的介孔特征(孔径在2～50 nm),BET比表面积和中孔体...     

人造土壤形成的第一个40年

Soil formation is often a very slow process that requires thousands and even millions of years. Human influence, occasionally on a par with the function of climate or geological forces, can accelerate the process and can be viewed as a distinct soil forming factor. This paper describes a soil, Haplic Regosol, in which anthrosolization dominates the soil forming process. Man-made soils, Technosols, were stabilized with techniques of ecological engineering (crib walls). We measured the main soil properties and focused on the movement of water (the reduction of soil weight is the key factor in stabilizing these calcschists). The newly deposited debris, sheltered by anthropic interventions, after four years differentiated an A/C profile while after forty years differentiated an O/A/AB/Bw/BC/C profile. Our results indicate that colonization by plants and the consequent success of vegetation establishment is influenced mainly by control of the factor of pedogenesis ‘topography’ and by the ability of these Technosols to retain nutrients.     

Pressure evaluation of 3D seamless knitted bras and conventional wired bras

Seamless knitting for making bras is a novel approach. The fitting evaluation of these products remains unknown and there is limited knowledge about the effects of knitting parameters on the bra tension. This study developed 3 styles of seamless knitted bras with various loop length and elastic yarn tension based on a 2² full factorial experimental design with one additional centre level. Therefore, a total of 3 × 5= 15 new seamless bra samples have been knitted. The skin pressure exerted by the new bras was compared with 4 commercial bras including 2 “cut and sewn” wired bras and 2 seamless knitted bras. Six women subjects of breast size 75B* in our newly developed breast sizing system were invited to wear all the bra samples. The skin pressure exerted by the bra was measured by the Novel pliance-X pressure sensors on 11 body positions. The results indicated that newly developed seamless bras showed lower pressure than the commercial bras, but had a considerably higher pressure at the cup base point. The new seamless bras with the largest loop length presented the lowest pressure values. Furthermore, empirical equations were established to predict 2 critical pressure points at “apex” and “side bottom band” from two major knitting parameters. This study provides the new knowledge of seamless knitted bra fitting and the resulted bra pressure, as well as some guidelines for seamless knitted product design and manufacturing.     

保护地黄瓜膜下滴灌及土壤中水分运行

2009年春季在河北省进行了保护地黄瓜滴灌试验和滴灌水分在土壤中运行的观察。结果表明：土壤绝对含水量（SAWC）与土壤水分张力（SMT）存在相关性。粘壤土SAWC（22.73%时,SMT=0.104 026×SAWC-2.866 41MPa,SAWC≥22.73%时SMT=3.527 1 lgSAWC-5.175 9MPa;粘土SAWC≤17.78%时SMT=0.108 329×SAWC-2.228 37MPa,SAWC（17.78%时SMT=1.530 3 lgSAWC-2.127 5MPa。据此计算,壤粘土温室越冬黄瓜的越冬期和初瓜期土壤水分张力应为-0.31～-0.25MPa,春季结果期为-0.13～-0.07MPa,但无论那个时期均不应高于-0.58MPa。保护地滴灌滴孔滴水速度以750 mL/h为宜,滴灌对土壤营养元素分布没有不同于漫灌的影响。     

皂荚皂素和油茶皂素表面活性研究

系统研究了皂荚皂素和油茶皂素的表面活性和泡沫性能,以及温度、盐度、水硬度、pH值等因素对皂素水溶液表面张力的影响.结果表明,皂荚皂素和油茶皂素水溶液临界胶束浓度(CMC)值(20℃)分别为0.1 和1.5g/L,最低表面张力( γ CMC)(20℃)分别为43.292和43.531mN/m,皂荚皂素表面活性高于油茶皂素.质量浓度2.5g/L的皂素水溶液,油茶皂素泡沫高度比皂荚皂素高25mm,油茶皂素起泡性能和稳泡性能均比皂荚皂素稍强.温度升高,油茶皂素和皂荚皂素的γ CMC均呈现明显下降趋势,而CMC值基本不变;pH值偏低或偏高时,皂素的CMC值略有降低;皂荚皂素和油茶皂素均有较好的耐盐和抗硬水能力.     

通风量对里氏木霉产纤维素酶的影响

用10 g/L纸浆作碳源,研究通风量对里氏木霉产纤维素酶的影响.在28℃、搅拌速率250 r/min、pH值4.8时,不调通风量或调节通风量控制溶解氧浓度(DOT),用10 L发酵罐产酶,测定菌丝质量浓度和纤维素酶酶活.结果表明:通风量一定时,DOT有时可能会低于临界DOT,有时又偏高,不利于菌丝生长.改变通风量,调节DOT为20%～30%时,最适宜于茵丝的生长代谢,菌丝质量浓度最高为3.12 g/L,比未调通风量时的最高值2.77 g/L增加12.6%,76 h滤纸酶活达3.55 IU/mL,比未调通风量时的最高值2.80 g/L提高26.8%.     

针刀干预对中期膝骨关节炎兔模型伸肌-屈肌萎缩状态及肌肉拉伸弹性模量的影响

目的 探索针刀治疗对中期膝骨关节炎（knee osteoarthrits,KOA）兔模型伸肌-屈肌萎缩状态及肌肉拉伸弹性模量的影响。方法 24只新西兰兔按体质量随机分为空白组（6只）及KOA造模组（18只）,造模组应用改良的Videman法制动6周建立KOA兔模型,解除固定后根据Lequesne评分再随机分为模型组、针刀组和西药组（每组6只）。随后各组分别进行干预治疗4周,治疗结束后,应用Lequesne评分标准进行行为学评价,兔股直肌、股二头肌分别进行HE染色及拉伸弹性模量检测。结果 （1）与模型组相比,针刀组和西药组能明显降低Lequesne评分（P<0.01）和改善局部疼痛程度（P<0.05或P<0.01）。（2）与模型组相比,针刀组和西药组可显著改善股直肌、股二头肌萎缩状态,表现在固定视野内肌纤维数量显著减少（P<0.01）、平均横截面积显著增加（P<0.01）。（3）与模型组相比,针刀组股直肌和股二头肌弹性模量（elasticity modulus,EM）显著降低（P<0.01）,西药组股直肌和股二头肌EM值明显降低（P<0.05）,且针刀组股直肌EM值低于西药组（P<0.05）。结论 针刀干预中期KOA兔具有改善关节功能及缓解疼痛的作用,减轻KOA兔股直肌、股二头肌肌肉萎缩状态,促进股直肌-股二头肌拉伸弹性模量的改善。