Contents of Total Phenolics and Ferulic Acid, and PAL Activity during Water Potential Changes in Leaves of Maize Single-Cross Hybrids of Different Drought Tolerance

The aim of this study was to determine whether the resistance and/or sensitivity to drought stress, can be attributed to the level of phenolic compounds in the leaves of maize genotypes. The experiments were carried out on seedlings of three maize genotypes characterized by different levels of drought resistance. Experiments with three periods of drought were conducted (8, 11 and 14 days), to obtain plants with different levels of water potential in leaves, which induced changes in the total phenolic content and ferulic acid, and l ‐phenylalanine ammonia‐lyase (PAL) activity. Only for the drought‐resistant genotype Tina, was the low water potential found to be correlated with the high level of the total phenolic content and ferulic acid, which is the main source of blue fluorescence emissions. Moreover, only for Tina were the highest intensities of blue fluorescence emission correlated with the low water potential in leaves. The phenolic compounds present in leaf tissues can protect the deeper situated mesophyll, by absorbing light reaching the leaf and transforming it into a blue fluorescence. Phenolic compounds can, in this way, function as photoprotectors limiting the excitation of chlorophyll during conditions of water deficit in leaves.     

河虾中汞含量测量不确定度研究

采用国标方法GB/T5009.17 -1996中的原子荧光光谱法测定河虾中汞含量 ,并对河虾中汞含量测量不确定度进行了系统的研究 ,试验结果表明:对汞含量的扩展不确定度为0.058±0.008。     

低盐海水罗氏沼虾养殖技术

就河口低盐海区罗氏沼虾幼虾培育及商品虾养成技术进行了综合阐述，包括池塘条件及准备，虾苗运输与放养，饲料投喂技术，隐蔽物设置，低盐海水水质调节技术，虾病防治及商品虾捕捞等。     

钼锑抗法测定饲料中微量砷

以探索一种新的测定化学元素砷的方法为目的,较详细地研究了砷钼杂多酸还原产物—砷钼蓝水相光度法,测定微量砷的方法,试验表明"砷钼蓝"在720nm处有最大吸收峰。砷含量在0～20μg/5ml范围内遵守朗伯 比尔定律,r=0 9993。方法用于对各种动物饲料中,砷含量的测定,结果较为满意。     

庄河青堆虾池的浮游生物

本文报道了庄河青堆水产公司虾池浮游生物的研究结果。1)放虾前施无机肥并定期纳入沙蚕,放虾后以人工投喂为主的庄河青堆虾池的浮游植物种类组成前期(5～6月)和后期(9月以后)以甲藻占优势,中期(7～8月)以蓝球藻、小环藻和小球藻等陆水种为主。2)水色与浮游植物种类组成密切相关。以硅藻为优势的黄褐色水为养虾的优良水质;以蓝球藻和小球藻为优势的淡绿色或翠绿色水为较好水质;而以甲藻为优势的深褐色或酱油色水为不良水质。3)浮游植物生物量多为5～30mg·L~(-1),叶绿素a为23.14(5.24～63.43)mg·m~(-3),叶绿素b为7.78(0.93～37.00)mg·m~(-3),叶绿素c为47.36(12.72～138.79)mg·m~(-3),叶绿素总量(a+b+c)为78.37(29.06～111.59)mg·m~(-3)。叶绿素a占浮游植物湿重的百分比为0.26(0.06～1.12)。浮游动物生物量平均大约为浮游植物生物量的1/3～1/8,以桡足类为主。     

ED-XRF法快速测定虾预混合饲料中钙、磷含量

虾预混合饲料中钙（Ca）、磷（P）含量直接影响虾的生长、发育和健康状况。传统的化学分析方法需要对虾预混合饲料进行复杂的预处理,取得测试结果需要花费数小时。采用一种简单、快捷的分析方法——能量色散X射线荧光光谱法（ED-XRF）,对虾预混合饲料进行粉碎、压片和测试,在数分钟内获得了样品的测试结果。ED-XRF法对Ca、P的检出限分别为43 mg/kg和163 mg/kg,定量限分别为142 mg/kg和544 mg/kg。对虾预混合饲料3^#样本连续测试6次,Ca、P的连续测定数据的极差分别为0.159%和0.013%,分别小于推荐性国家标准中Ca、P含量检测的重复性临界差CrR₉₅（6）0.239%和0.031%,表明ED-XRF法满足推荐性国家标准对饲料中Ca、P含量测定的要求。通过对10个已定值的虾预混合饲料样品进行Ca、P含量测定,ED-XRF法的测定值与推荐性国家标准中相关方法测定值的相对差值不大于4.55%。综上表明,ED-XRF法具有较高的精密度和准确度,可用于虾预混合饲料生产企业对Ca、P元素添加量的监控。     

Effect of contrast and local anesthetic on dye spread following transversus abdominis plane injection in dog cadavers

ObjectiveTo determine whether the addition of bupivacaine or contrast medium to methylene blue dye would affect dye distribution following ultrasound (US)-guided transversus abdominis plane (TAP) injections.Study designProspective, randomized, blinded cadaveric study.AnimalsA total of 29 fresh Beagle dog cadavers.MethodsEach hemiabdomen (n = 58) was randomized into one of three groups: group M, 1% methylene blue; group MB, 50:50 mixture of 1% methylene blue and 0.5% bupivacaine; group MC, 25:75 mixture of 1% methylene blue and contrast agent (iohexol). TAP injections (0.5 mL kg^–1) were performed bilaterally by a trained individual followed by dissection of the abdominal walls. Craniocaudal and dorsoventral spread along tissue planes was measured. Staining of branches of the thoracic and lumbar spinal nerves was considered successful when dye on the nerve was >10 mm. One-way anova with post hoc Tukey test was used to compare craniocaudal and dorsoventral spread and Kruskal–Wallis test to compare incidence of nerve staining among groups.ResultsTAP injections were successful in 52 out of 58 hemiabdomens. Dorsoventral spread was greater for group M (60 ± 10 mm) compared with MC (49 ± 9 mm; p = 0.01) but not MB (52 ± 9 mm; p = 0.09). No difference was found in craniocaudal spread or number of nerves stained among groups.Conclusion and clinical relevanceThe significant difference found in spread of tissue staining between methylene blue alone and methylene blue mixed with contrast in the TAP blocks should be kept in mind when interpreting dye-based cadaveric regional anesthesia studies.     

浅谈猪繁殖与呼吸综合征的防控措施

猪繁殖与呼吸综合征(Porcine reproductive and respiratory syndrome,PRRS)是由猪繁殖与呼吸综合征病毒(PRRSV)引起的猪的一种高度传染性疾病,又称"猪蓝耳病"。笔者通过引种管理、生物安全、生产流程、疫苗免疫以及实验室监测这五项措施帮助不同的猪场实现对猪蓝耳病的有效防控。     

Taxonomic status of Chinese blue sheep (Pseudois nayaur): new evidence of a distinct subspecies

The blue sheep is an endemic species to the Qinghai‐Tibet Plateau and surrounding regions. It has been regarded as having 2 subspecies: Pseudois nayaur nayaur and P. n. szechuanensis. However, such a classification remains controversial. Herein, we analyze 10 microsatellite loci and part of the mitochondrial control region for clarification in such taxonomic debates. We use samples from 168 individuals from 6 geographic populations covering almost all the distribution areas of the species in China to carry out comparisons. Phylogenetic trees derived from both the microsatellite and mitochondrial markers combined with the discriminant analysis of principal components (DAPC) and the STRUCTURE analysis reveal that the individuals in the Helan Mountains are well grouped with a distinct evolutionary lineage and are significantly different from the other populations of P. n. szechuanensis according to Fst values, implying that this isolated population should be categorized as a valid subspecies; namely, Pseudois nayaur alashanicus. The isolation‐by‐distance (IBD) analysis shows a significant positive relationship between genetic and geographical distances among the populations.