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951.
本文基于NET4.0,采用C#语言和ADO.NET数据访问技术,结合SQL Server数据库,开发建立了数字化木材标本管理系统,实现了木材标本的数字化管理和快捷检索.本系统具有运行速度高、信息处理能力强、人机界面直观、功能齐全、通用性强、硬件环境要求低等特点,为促进木材科学与数字化技术水平的提高提供了技术支持.  相似文献   
952.
The color degradation of aqueous solutions of six natural red pigment extracts (elderberry, red cabbage, hibiscus, red beet, Opuntia fruits and red cochineal) used commercially as food colorants was investigated at temperatures between 50 and 90 °C. Color degradation was studied in respect to both spectral properties and visual color. The remaining absorbance at 535 nm as a function of the incubation time and temperature was used to quantify the degradation process. Red cochineal was the most thermoresistant extract with a remaining absorbance of 95 % after 6 h at 90 °C. Anthocyanin extracts (elderberry, red cabbage, hibiscus) showed remaining absorbance percentages of 63.8, 46.1 and 26.7, respectively. Betacyanin extracts (red beet, Opuntia fruits) were the most thermosensitive maintaining only 12.5 and 1.7 %, respectively, of the initial absorbance at 535 nm. Applying a first-order kinetic model to the degradation processes, reaction rate constants (k) and half-life periods (t 1/2 ) were calculated. The temperature dependence of the degradation rate constant obeyed the Arrhenius relationship, with activation energies (E a ) ranging between 3.02 and 53.37 kJ?mol?1. The higher activation energy values indicated greater temperature sensitivity. Changes in visual color attributes corroborated the high thermal stability of the red cochineal extract.  相似文献   
953.
肖牧  徐健  何乐  刘春林  阮颖 《作物研究》2013,(3):213-216
NPR1是水杨酸介导的系统获得性抗性(SAR)途径中不可或缺的一个转录辅助因子。在SA诱导下,NPR1被转运至细胞核内并与一些转录因子结合,以启动下游基因的表达。本研究通过PCR扩增获得拟南芥中NPR1基因CDS序列,经过限制性内切酶酶切后在T4连接酶作用下分别克隆至pGBKT7与pGADT7酵母表达载体上,并成功将其转化至Gold酵母菌株中。为利用酵母双杂交筛选NPR1参与形成的转录复合体中其它可能存在的蛋白质并阐明其在植物防御信号传导途径中的互作模式奠定了基础。  相似文献   
954.
多目标跟踪是视频监控等领域的一项关键技术。阐述目标跟踪算法的研究现状,运用灰度阈值分割,基于特征和主动轮廓跟踪方法实现对多只运动果蝇进行目标识别与跟踪。运用C#以及emgu开发应用程序予以系统实现。经验证,该系统识别率高,具有稳健的跟踪效果。  相似文献   
955.
An approximately 8‐year‐old male castrated Dutch rabbit was evaluated for a 6‐day history of respiratory signs, which began as sneezing and progressed to tachypnea with anorexia. On physical examination, tachypnea and pale mucous membranes were noted. Thoracic radiographs revealed a soft tissue pulmonary mass, fine‐needle aspirates of which confirmed a neoplasia with malignant features suspicious for a histiocytic sarcoma. The rabbit was discharged and due to a rapidly deteriorating condition, the owner declined chemotherapy with Lomustine and elected euthanasia of the rabbit. The affected lung was submitted for histopathology. Histologic sections of the lung were characterized by clusters of histiocytic cells and multinucleated giant cells with occasional invasion of blood and lymphatic vessels. The histologic diagnosis was histiocytic sarcoma. To the authors' knowledge, this is the first case report of histiocytic sarcoma in a rabbit. Based on the clinical and radiologic findings in this case, histiocytic sarcoma should be included in the list of differentials for rabbits presenting with respiratory signs and evidence of a pulmonary mass.  相似文献   
956.
Five strains of Rhipicephalus (Boophilus) microplus collected from Tamaulipas Mexico were tested for resistance against several classes of acaricides commonly used. All were resistant to fipronil. Four of five were co-resistant to permethrin and coumaphos in addition to being resistant to fipronil. One strain, El Zamora was found multi-resistant to permethrin, coumaphos, fipronil, and amitraz. Selection with fipronil for 3 generations produced a resistance ratio of 8.3 and 9.4 at the LC50 and the LC99 estimates, respectively. Permethrin resistance in El Zamora was possibly linked to elevated esterase (CZEST9) and could be a contributing factor of resistance to fipronil. The implications of resistance for the control of the southern cattle tick in the future are discussed.  相似文献   
957.
将猪圆环病毒2型(PCV2)接种猪血管内皮细胞(VEC),于接种后不同时间收集细胞及上清,利用实时荧光定量PCR和ELISA技术分析VEC相关免疫调节分子表达变化。与对照组相比,PCV2感染后血管内皮生长因子(VEGF)、IL-6与巨噬细胞集落刺激因子(M-CSF)的mRNA水平变化趋势基本一致,VEGF和M-CSF在感染后12h显著上调,IL-6与M-CSF在48h显著下调;MCP-1和IL-8在感染后4h和48h均显著上调,且IL-8在24h时上调显著,72h下调显著。蛋白水平上,VEGF在4h显著下降,24h显著增高;IL-8在4h和24h显著上升。以上结果表明,PCV2体外感染导致VEC免疫调节功能分子表达异常,其炎性趋化、黏附能力以及对树突状细胞(DC)的分化、成熟等免疫调节功能可能受到影响。  相似文献   
958.
在探明小孢拟盘多毛孢(Pestalotiopsis microspora)PM-1菌株产生紫杉醇的基础上,本试验系统研究了菌龄、孢壁降解酶、稳渗剂、酶解时间及温度和培养基初始pH值对小孢拟盘多毛孢PM-1菌株原生质体制备和再生的影响,以期建立稳定高效的原生质体制备和再生体系。研究发现,小孢拟盘多毛孢PM-1菌株原生质体制备受多种因素影响,其中主要因素为混合酶系中各种酶的浓度配比及酶解时间,综合各项试验结果,明确PM-1菌株原生质体制备适宜的条件为分生孢子悬浮液接种Fries液体培养基(pH5.5)振荡培养18h,Lywallzyme(7.5g/L)、Drislase(7.5g/L)、Snailase(7.5g/L)3种酶的混合溶液,在36℃下酶解3h,以0.7mol/L NaCl作为稳渗剂制备的原生质体产量最高。研究结果为菌株的遗传改良和提高菌株的紫杉醇产生率奠定了基础。  相似文献   
959.
The epidemiology of subclinical salmonellosis in wild birds in a region of high Salmonella prevalence in pigs was studied. Three hundred and seventy‐nine faecal samples from 921 birds trapped in 31 locations nearby pig premises, and 431 samples from 581 birds of 10 natural settings far from pig farms were analysed for the presence of Salmonella spp. Positive samples were serotyped and analysed for antimicrobial resistance (AR). Phage typing and pulsed‐field gel electrophoresis (PFGE) on Salmonella Typhimurium isolates were also carried out. The overall proportion of Salmonella‐positive samples was 1.85% (95% CI = 0.93, 2.77). Salmonella isolation was positively associated with samples collected from birds in the proximity of a pig operation (OR = 16.5; 95% CI = 5.17, 52.65), and from non‐migratory (or short‐distance migration) birds (OR = 7.6; 95% CI = 1.20, 48.04) and negatively related to mostly granivorous birds (OR = 0.4; 95% CI = 0.15, 1.13). Salmonella Typhimurium was the most prevalent serotype and four different XbaI PFGE patterns were observed that matched the four phage types identified (U310, U311, DT164 and DT56). Only 20% of the strains showed multi‐AR. In three farms, a high degree of homogeneity among isolates from different birds was observed. These findings suggested that pig farms may act as amplifiers of this infection among wild birds, and the degree of bird density may have much to do on this transmission. Some of the Salmonella serotypes isolated from bird faeces were of potential zoonotic transmission and associated with AR. Monitoring salmonellosis in wild bird is advised.  相似文献   
960.
Cattle play a very important role in agriculture and food security in Vietnam. A high level of cattle diversity exists and serves different needs of Vietnamese cattle keepers but has not yet been molecularly characterized. This study evaluates the genetic diversity and structure of Vietnamese indigenous cattle populations, using microsatellite markers. A total of 410 individuals from six indigenous cattle populations and an exotic breed was characterized using 27 microsatellite markers A total of 362 alleles was detected and the number of alleles per locus ranged from 8 (INRA005 and ILSTS005) to 17 (ETH185). The level of gene diversity was high indicated by a mean expected heterozygosity (He) across populations and loci of 0.73. Level of inbreeding (mean FIS=0.05) and genetic differentiation (mean FST=0.04) was moderate. The phylogenetic tree based on Reynolds genetic distance reflected geographic distances. Structure analysis indicated five homogeneous clusters. The Brahman, Lang Son, Ha Giang and U Dau Riu cattle were assigned to independent clusters while Nghe An, Thanh Hoa and Phu Yen cattle were grouped in a single cluster. We conclude that Vietnamese indigenous cattle have high levels of genetic diversity and distinct genetic structures. Based on these results, we recommend that for conservation homogenous populations (Nghe An, Thanh Hoa and Phu Yen) can be grouped to reduce costs and U Dau Riu, Lang Son and Ha Giang populations should be conserved separately to avoid loss of genetic diversity.  相似文献   
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