乳过氧化氢酶体系在牛乳保鲜中的应用

由于三聚氰胺事件影响,乳品安全已日益得到广大消费者的重视,生物酶制剂在牛乳保鲜中取得了良好的效果。本文从组成、抗菌机理、保鲜效果等方面探讨了鲜牛奶中固有的一种天然抗菌活性体系-乳过氧化物酶体系(LPS)在牛乳保鲜中的应用,并结合当前研究进展论述了它在牛乳保鲜中的效果,为牛乳保鲜提供了新的方法。     

浅淡以工业化理念引领动物卫生监督工作晋档升级

动物卫生监督工作担负着保障"三大安全"的历史任务,是保障畜牧业健康发展的关键环节,如何使动物卫生监督工作适应当代畜牧业发展趋势,以工业化理念引领我市动物卫生监督工作晋档升级值得深思。本文对以工业化理念抓我市动物卫生监督工作的意义及动物卫生监督工作面临的形势进行了分析,从实行任务项目化管理、推行标准化及规范化、集成化、信息化、社会化管理及打造品牌效益等六个方面阐述了以工业化理念谋划动物卫生监督工作晋档升级总体思路,为我市动物卫生监督工作平稳较快发展提供科学理论依据。     

青苹果片过热蒸汽瞬时压降膨化动力研究

针对过热蒸汽瞬时压降膨化动力不明晰、膨化程度调控困难的问题,建立了片状物料膨化动力通用数学模型,表明膨化的能量源自于物料内部过热液体闪急蒸发做功和过热蒸汽瞬时释放做功2部分。由于不同含水率的待膨化样品孔隙率不同,而且膨化前过蒸汽加热过程中热交换所产生的冷凝水质量也不同,从而膨化前样品的孔隙率产生了不同的变化。因此,膨化度与物料的含水率、孔隙度有关,也与过热蒸汽的状态有关。以青苹果片为试验材料,结果表明待膨化样品的孔隙率随着含水率的增大而明显减小。采用温度和压力分别为430~470 K和0.1~0.5 MPa、过热蒸汽膨化含水率为15%~35%的青苹果片,运用建立的膨化动力模型可有效地预测和评价膨化条件与膨化度的关系(R~20.89)。增大蒸汽压力,对冷凝水的影响不大,可增大过热液体和过热蒸汽做功,对提升膨化动力和膨化效果最明显;升高过热蒸汽温度仅能提高过热液体做功,但显著增大的冷凝水量使得过热蒸汽做功减小,对提高膨化动力及膨化效果不明显;增加物料的含水率明显地增大过热液体做功,但是由于冷凝水量明显增加而降低了过热蒸汽做功,总体上表现为较大程度增大了膨化动力和膨化度。     

重金属污水处理的研究与发展

对重金属污水处理的各种方法分别进行分析,指出其不足之处。并对生物处理重金属污染技术重点介绍,该技术是未来重金属污水处理的主要方法。生物技术具有原料丰富、效率高、成本低、环境友好无污染等优点。现阶段,很多生物技术尚处于实验室阶段,大规模应用于工业重金属污水处理还需要进一步的研究和发展。      

免疫遗传算法的研究及其在节水灌溉中的应用

根据生物的免疫原理,将免疫算法中的抗体多样性的维持机制、记忆机制、促进抑制机制引入到遗传算法中,在标准遗传算法的基础上提出了加速实数编码的免疫遗传算法.研究表明,免疫遗传算法改进了基本遗传算法群体多样性差、搜索区间大和免疫算法容易陷入局部最优的平衡态,以及进化后期搜索停滞不前的性能,使其快速成熟的收敛同时又提高了局部寻优和全局寻优的搜索能力.针对黑龙江省半干旱地区水资源紧缺的问题,用免疫遗传算法进行水量优化分配,结果表明实码加速免疫速遗传算法有较好的实用性能与稳定性能.     

不同品种大果沙棘果实品质研究

在山西省晋中市太谷县试验地,对引进的无刺丰、西伯利亚红晕、壮圆黄、杂交3号和杂交4号5个大果沙棘品种,进行了果实性状及结实情况的研究,结果表明:5个引进大果沙棘的百果鲜重和果柄长度都远大于对照中国沙棘,果实中的维生素C、胡萝卜素和总黄酮含量则远低于对照中国沙棘。     

Supplemental Chromium Picolinate Promotes Growth of Broiler Chickens by Enhancing Insulin Receptor Gene Expression

Chromium has been recognized for decades as a nutritional factor that promotes the growth of broiler chickens, but the molecular mechanism is still not clearly understood. The present study was designed to investigate the physiological and molecular mechanisms of the effects of supplemental chromium picolinate on the growth of broiler chickens. A total of 144 21-day-old Arbor Acres male broiler chicks were randomly divided into a control and an experimental group. The control group was fed a basal diet, and the experimental group was fed the same basal diet supplemented with 200 μg/kg chromium picolinate. The experiment lasted for three weeks from day 28 to 42 of the birds.. Supplementation with 200 μg/kg chromium picolinate significantly increased body weight (P < 0.05). Serum insulin levels in chickens of the experimental group were increased significantly (P < 0.05), whereas serum their glucose concentrations were decreased (P < 0.05). No significant changes were observed in serum lipid profiles in chickens fed the diet supplemented with chromium picolinate. Gene expression levels of the insulin receptor (IR) and insulin receptor substrate 1 (IRS-1), two pivotal components of the insulin signaling pathway, were also investigated using Real-time quantitative PCR. IR expression was significantly (P < 0.05) increased following chromium supplementation. Therefore, supplemental chromium picolinate had a beneficial effect on the growth of broilers. In agreement with observations in mammals, chromium might exert its effect via potentiating insulin action, and ultimately by stimulating anabolism without altering body composition in chickens.     

The spatiotemporal dynamics of rapid urban growth in the Nanjing metropolitan region of China

To better understand the spatio-temporal dynamics of the urban landscape of the Nanjing metropolitan region, China, we conducted a series of spatial analyses using remotely sensed data of 1979, 1988, 1998, 2000 and 2003. The results showed that the urban area as well as the growth rate increased significantly. Three urban growth types were distinguished: infilling, edge-expansion and spontaneous growth. The pattern of urban growth can be described as a ‘diffusion–coalescence’ phase transition. Although edge-expansion was the most common growth type, the spontaneous growth took a greater proportion in area and patch number than the infilling growth at the early stage, but its dominance decreased as urbanization proceeded from the diffusion phase to the coalescence phase. Hot-zones of urban growth and the distribution pattern of newly urbanized areas in different periods were studied with a buffering analysis. More than 80% of the growth area occurred within a zone of 1.4 km wide outwards from the pre-growth urban fringes. The spatial distribution of newly urbanized areas in each period showed a uniform negative exponential decline relative to the distance from the edge of the urban patches. There existed an outward wave-like shifting of urban growth hot-zones, but the distance-growth area curves varied at different stages of urban growth. While a double-peaked pattern usually occurred in the diffusion phase, a single-peaked pattern was common in the coalescence phase.     

喹草酮与辛酰溴苯腈复配应用于小麦田的除草效果及对小麦的安全性

为明确新型除草剂喹草酮应用于小麦田的除草效果及对小麦的安全性,在温室内采用共毒系数法对喹草酮与辛酰溴苯腈联合作用进行测定,并验证喹草酮与辛酰溴苯腈两者混用以及与双氟磺草胺三者混用时对小麦田杂草的防效,以及对小麦的安全性。温室试验结果表明,喹草酮对阿拉伯婆婆纳Veronica persica防效优,试验剂量下全部死亡,对播娘蒿Descurainia sophia和麦家公Lithospermum arvense的GR₅₀分别为12.67 g (a.i.)/hm²和152.99 g (a.i.)/hm²;辛酰溴苯腈对播娘蒿和麦家公防效优,其GR₅₀分别为26.22 g (a.i.)/hm²和13.36 g (a.i.)/hm²,对阿拉伯婆婆纳防效略差,GR₅₀为85.12 g (a.i.)/hm²。喹草酮与辛酰溴苯腈按有效成分用量1∶1～1∶2.5配比时,阿拉伯婆婆纳全部死亡,对播娘蒿的共毒系数在140.34～202....