基于GIS的丹东地区柞蚕农业气候区划

根据当地柞蚕实际生产与气象条件的关系,确定了柞蚕生产的农业气候区划指标.运用丹东地区1:250000地形数据和丹东及周边地区气象站30年的气候资料,建立区划指标小网格推算模型,应用GIS技术对丹东地区柞蚕生产进行气候区划,将该区划分为气候最适宜区、气候适宜区、气候次适宜区和气候不适宜区,为丹东柞蚕生产的合理布局和发展提供参考依据.     

The evolution and application of enzymes in the animal feed industry: the role of data interpretation

ABSTRACT

1. Enzymes have been used commercially for nearly 40 years and save significant costs through sparing of expensive nutrients but the mechanism by which this is achieved is still debated.

2. The research focused on non-starch polysaccharidase (NSPase) enzymes is used as an example of where greater progress could have been made if the details of the work had been described more fully and the analysis of the data generated had been broader in scope and more critical.

3. Lack of standardisation of the details presented in the materials and methods has been identified as a significant barrier to meaningful retrospective analysis and thus limits advances in the understanding of the mode of action of these enzymes.

4. The identity of the enzyme employed and its activity is often lacking, and more importantly the purity is rarely disclosed. Contaminant activities which are neither listed nor assayed could play a significant role in the responses observed.

5. The dose optimum of most enzymes is often considerably higher than that employed in most studies. Thus studies claiming synergy between two ‘activities’ should ensure that the response is not related to each enzyme simply augmenting the dose of just one activity in the finished feed. This is a common problem, and coupled with the lack of factorial experiments to justify the presence of each enzyme in a multi-enzyme product, it is not surprising that there is still debate as to whether single or multi-enzymes are best suited poultry rations.

6. The three proposed mechanisms for NSPases (viscosity, cell wall and prebiotic) are discussed, and along with their strengths and weaknesses it is suggested that a re-evaluation of each is needed. Viscosity may have to be re-evaluated as being a function not only of the cereal being fed, but of the age of the animal as well. The cell wall theory as described is poorly modelled in vitro and hence the validity of these data is questioned. The prebiotic theory may need significant modification as it appears that the quantities of oligomers produced are insufficient to generate the additional volatile fatty acids (VFA)’s reported. It is likely that all three mechanisms play a role in the responses observed, but the prebiotic mechanism probably plays by far the most important part in low viscosity diets.

7. Future research would be improved if it considered all potential mechanisms when designing a trial. Significant failings are apparent as a result of adherence to tenets in explanation of the results. Most importantly, it should be emphasised that a hypothesis is there to be tested, not defended.     

Cell direct reprogramming：a new technique for treating diabetes

Diabetes is characterized by an absolute or relative deficiency in β-cell mass, which cannot be reversed with existing therapeutic strategies. The restoration of the endogenous islet β-cells can stabilize the level of blood glucose. The islet β-cells can be obtained from the directional differentiation of stem cells, but the process is complex and has the risk of teratomas generation. Cell direct reprogramming, one terminal differentiated cell can transdifferentiate into another kind of terminal differentiated cell, which is other than directional differentiation from stem cells. Direct reprogramming gives rise to the generation of islet β-cells from one terminal differentiated cell, may be preferable for diabetes therapy because of its unique advantage.     

甲状腺素对猪小肠上皮细胞miR-let-7a基因表达及细胞增殖的影响

miR-let-7a在动物细胞的分化、增殖与凋亡等方面发挥越来越重要的作用。甲状腺激素(TH)作用非常广泛,机体的每个细胞几乎都是TH作用的靶细胞,其可以促进组织分化、生长和成熟。本实验用甲状腺素(T4)浓度分别为(0、0.02、0.03、0.05、0.075、0.1、0.2μmol/L)在体外培养猪的小肠上皮细胞。结果表明:T4处理组的细胞体积形态相对于空白对照组没有明显变化;当T4添加浓度为0.03μmol/L时,细胞的增殖率显著低于其他组(P0.05);当T4浓度为0~0.03μmol/L时,let-7a的表达随着添加剂量的增加而升高,浓度从0.03~0.2μmol/L变化时,let-7a的表达呈现降低趋势,浓度为0.03μmol/L时表达量极显著高于其他组(P0.01)。let-7a的表达量与细胞增殖呈负相关。     

多径衰落信道下OFDM系统的符号同步方法研究

由于在正交频分复用（OFDM）的系统中存在符号时间同步误差，为了消除这种误差，提出了工作在多径衰落信道的符号时间频移（STO）估计方法，即基于CP的符号时间偏移估计和基于训练符号的符号时间偏移估计，通过仿真对基于循环序列（CP）估计技术的最大似然法（ML）和基于训练符号的最小均方差异法（Classen）两类性能比较分析，在无载波频移条件下，ML算法精确度更高，当存在载波频移时，Classen算法精确度更高。     

提高二倍体马铃薯原始栽培种原生质体分离与分裂频率的研究

为获得较高的原生质体分离和分裂频率,试验以马铃薯二倍体原始栽培种‘47-33’‘5-19’试管苗叶片为材料,进行了原生质体游离和培养的研究.结果表明:培养21d的两品系试管苗叶片均在含有2.0%纤维素酶+0.5%果胶酶+0.25%离析酶,渗透压为0.35mol/L的酶解液中解离效果最好,原生质体产量分别为2.31×106个/gFW和2.52×106个/gFW;在28℃酶解温度条件下缓慢摇动14h或1h静置+13h缓慢摇动的,可促进叶片原生质体的大量释放.此外,1.0mg/L NAA+0.5mg/L 2,4-D+0.4mg/L BAP外源激素组合有利于叶片原生质体的分裂,‘47-33’‘5-19’原生质体一次分裂频率分别达到8.85%和12.56%.在0.35mol/L渗透压的液体培养基中,‘47-33’叶片原生质体分裂更早,分裂频率达13.85%.研究获得了稳定的原生质体分离体系以及较好的原生质体培养条件,为马铃薯二倍体原始栽培种的体细胞融合奠定了基础.     

近15年我国土地利用分区研究进展

通过查阅21世纪以来的大量文献和对比分析,总结了国内土地利用分区的研究动态。结果表明院国内土地利用分区类型呈多元化,以省、市、县级为尺度和采用聚类分析法、GIS技术的研究较多,基于个案研究提出了新的理论、方法模型等,有效地对土地利用分区进行了探索,但也存在问题和不足;并指出其发展趋势是分区理论深入化、分区制度完善化、分区方法集成化及信息化。     

牛羊胎盘免疫调节因子的提取及对PANC-Ⅰ增殖和迁移影响的比较

胎盘免疫调节因子(placenta immunoregulating factor,PF)是从胎盘提取的小分子多肽,对病毒性疾病、免疫缺陷疾病及恶性肿瘤等具有潜在的临床应用价值.为检测牛(Bos taurus)和绵羊(Ovis aries)胎盘免疫调节因对人(Homo sapiens)胰腺癌细胞(pancreatic cancer cells-Ⅰ,PANC-Ⅰ)增殖与迁移的影响,本研究对从屠宰场获得的牛和绵羊胎盘进行分离,利用双酶水解法制备PF,将质量浓度为100～2 000 ng/mL的牛、羊PF作用于体外培养的PANC-Ⅰ细胞,以3-(4,5-二甲基噻唑-2-基)-5-(3-羧甲酯基)-2-(4-磺苯基)-2H-四唑(3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium,MTS)法观察细胞增殖抑制率,应用流式细胞技术检测其对PANC-Ⅰ细胞周期的影响.并利用Transwell迁移实验检测添加PF对PANC-Ⅰ细胞迁移能力的影响,同时通过实时荧光定量PCR法检测肿瘤抑制基因(tumor suppressor gene,PS3)和细胞周期依赖性蛋白激酶抑制因子1A基因(cyclin-dependent kinaseinhibitor 1A,P21)的表达情况.结果显示,17.11 g绵羊胎盘制得0.588 mg PF,6.61 g牛胎盘制得0.312 mgPF,胎盘质量与所得PF的质量比约为20 000∶1.在体外培养的PANC-Ⅰ细胞培养液中添加PF,从形态上观察,牛羊PF对PANC-Ⅰ细胞没有明显的影响.绵羊PF处理后PANC-Ⅰ细胞增殖抑制率为9.75％～22.89％,牛PF处理后PANC-Ⅰ细胞增殖抑制率为-3.81％～23.56％,增殖抑制率最显著的绵羊PF浓度为500 ng/mL,牛PF浓度为1 000 ng/mL.绵羊PF在浓度为500 ng/mL时,PANC-Ⅰ细胞的PI和SPF最低,而牛PF各浓度下的胰腺癌细胞增殖指数(proliferation index,PI)和增殖活性(S-phase fraction,SPF)没有明显的变化.同时,牛羊PF对PANC-Ⅰ细胞的迁移能力无显著影响.牛羊PF使PANC-Ⅰ细胞P53表达上调而P21表达下调.上述结果表明,在一定浓度下,PF对体外培养的PANC-Ⅰ细胞增殖有负调控作用,且牛羊胎盘免疫调节因子对胰腺癌细胞的影响不同,可能因为其存在的活性成分有区别.本研究为胰腺癌的治疗提供了新的思路.     

Influence of MUD on the System Capability of CDMA

In CDMA communication system, the relativities between users result in Multiple Access Interference (MAI). With the increase of users, MAI becomes the main jam of broadband CDMA communication system. Multi-User Detection (MUD) is the most important technology of anti-jamming in the broadband CDMA communication system, which can eliminates MAI effectively by using the information of all user signals to detection single. This paper analyze the expression of system capability without MUD and with MUD, and puts forward the way to increase system capability by using MUD. Then the influence of MUD on CDMA system capability is discussed by MATLAB emulation. Basing analysis and emulation, the conclusion is got: the higher the MUD efficiency, the better the improvement of CDMA system capability; under the same MUD efficiency, the lower data rate, the smaller inter-cell interference, the lower the ratio of bit energy to power spectrum, the better the improvement of CDMA system capability.