Seroprevalence and Risk Factors Associated With Corynebacterium pseudotuberculosis Detectable Antibodies in Equids in Alabama

A cross-sectional serological survey was carried out to screen the equine population of the nonendemic state of Alabama for the presence of detectable antibody titers against Corynebacterium pseudotuberculosis. A second objective was to determine the association of detectable titers with risk factors such as exposure to ruminants or previous travel to endemic states. A total of 342 equine serum samples from 40 Alabama counties were analyzed using the synergistic hemolysis inhibition test (SHI). The prevalence of detectable antibody titers (≥1:8) was 52.5% (95% confidence interval [CI], 47%–57.9%). Titers ≥1:128 were detected in 2.63% (95% CI, 1.2%–4.9%), and titers ≥1:512 were detected in 0.3% (95% CI, 0%–1.6%) of the sampled population. In the final generalized linear model, age (P < .001), breed (P = .023), and contact with cattle (P = .05) were associated with increasing SHI titers. Contact with goats was associated in the initial but not in the final analysis (P = .19). Previous travel was not associated with increasing SHI titer (P = .97). The results demonstrated a high prevalence of low detectable titers and low prevalence of titers ≥ 1:128 in a nonendemic population. Further evaluation of SHI cutoff titers and accuracy is warranted to reduce the risk of a false positive diagnosis.     

A Method for State Diagnosis of Grounding Grid

This paper discuses the method with which the corrosion of the grounding grid can be diagnosed .A grounding grid can handled as a circuit network. With the application of circuit network graph theory and the fault diagnosis theory of analog circuit and optimization, the fault diagnosis equations can be set up. This equations is figured out by Matlab, and the corrosion status of the grounding grid can be deduced from the result.     

电偶腐蚀和缝隙腐蚀的发生及预防

主要介绍了电偶腐蚀和缝隙腐蚀的定义、发生原理、常见形式及相应的预防措施。     

木霉菌对苹果主要真菌病害的抑制及其在土壤中的定殖作用

以胶东半岛老的果园中土壤为试材,采用逐步稀释法,涂平板于孟加拉红培养基中,根据形态和分子方法鉴定分离木霉菌。分离出的木霉菌与苹果主要病害对峙培养在不同pH的培养基上,观察不同pH条件下,对真菌病害的抑制效果。土壤有机质和pH是目前胶东果园的主要问题,采用正交法设计,研究了不同的土壤条件对木霉菌生长的影响。结果表明:在不同pH条件下,木霉菌抑制苹果病原真菌的效果不同,木霉菌在不同的pH条件下对腐烂病(Valsa mali)和炭疽病(Colletotrichum gloeosporioides)均可以抑制,但对轮纹病(Physalospora piricola Nose)只有在pH 6.0时没有效果外,其它pH时都对轮纹病有抑制作用。在土壤pH 6.5和土壤有机质含量为75 g·kg^-1时,最有利于木霉菌定殖。同时还发现木霉菌对土壤的pH具有调节作用,无论在碱性条件下,还是酸性条件下,均可以使土壤pH趋于中性,另外木霉菌可以增加土壤有机质含量,特别是在高土壤有机质含量的情况下,增加更加显著。总之,分离出的木霉菌对苹果腐烂病、炭疽病和轮纹病抑制效果好。土壤pH和有机质含量对木霉菌的生长有影响,高土壤有机质含量和中性土壤有利于木霉菌定殖。另外,木霉菌能有效地改良土壤有机质含量和土壤pH。     

氟磺胺草醚的生物测定方法研究

试验利用对氟磺胺草醚敏感的玉米、向日葵、高粱为指示作物,利用土培法研究了不同条件下,氟磺胺草醚不同浓度对作物的抑制作用,并建立了氟磺胺草醚玉米生物测定方法——玉米株高法.试验结果表明,最佳生物测定条件为在27℃条件下,培养120 h.研究结果对土壤中氟磺胺草醚的快速测定和轮作换茬具有重要意义.     

Nitrous oxide fluxes and denitrification sensitivity to temperature in Irish pasture soils

Nitrous oxide (N₂O) emissions from grazed pastures constitute approximately 28% of total global anthropogenic N₂O emissions. The aims of this study were to investigate the effect of inorganic N fertilizer application on fluxes of N₂O, quantify the emission factors (EFs) for a sandy loam soil which is typical of large areas in Ireland and to investigate denitrification sensitivity to temperature. Nitrous oxide flux measurements from a cut and grazed pasture field for 1 year and denitrification laboratory incubation were carried out. The soil pH was 7.3 and had a mean organic C and N content at 0–20 cm of 44.1 and 4.4 g/kg dry weight, respectively. The highest observed peaks of N₂O fluxes of 67 and 38.7 g N₂O‐N per hectare per day were associated with times of application of inorganic N fertilizer. Annual fluxes of N₂O from control and fertilized treatments were 1 and 2.4 kg N₂O‐N per hectare, respectively. Approximately 63% of the annual flux was associated with N fertilizer application. Multiple regression analysis revealed that soil nitrate and the interaction between soil nitrate and soil water content were the main factors controlling N₂O flux from the soil. The derived EF of 0.83% was approximately 66% of the IPCC default EF value of 1.25% as used by the Irish EPA to estimate greenhouse gases (GHGs) in Ireland. The IPCC‐revised EF value is 0.9%. A highly significant exponential regression (r² = 0.98) was found between denitrification and incubation temperature. The calculated Q₁₀ ranged from 4.4 to 6.2 for a temperature range of 10–25 °C and the activation energy was 47 kJ/mol. Our results show that denitrification is very sensitive to increasing temperature, suggesting that future global warming could lead to a significant increase in soil denitrification and consequently N₂O fluxes from soils.     

“芪蓝饮”及不同提取成分对NDV在鸡胚成纤维细胞中增殖的影响

为评价新兽药"芪蓝饮"及其不同提取成分的体外抗病毒活性,本试验通过细胞病变抑制法和MTT比色法检测了各提取成分对新城疫病毒(NDV)感染鸡胚成纤维细胞(CEF)过程的影响。结果显示,在3种加药方式中"芪蓝饮"原药(QLY)直接杀灭NDV的作用最强,其抑制率最高为128.85%;原药总多糖(TPS)干扰NDV的增殖作用最强,其抑制率最高为130.23%;原药总萜类(TT)直接杀灭NDV的作用最强,其抑制率最高为146.15%;板蓝根总生物碱(RIA)及其水溶性部位(RIAw)和酸性部位(RIAa)对抗NDV的方式是多环节的。综上所述,"芪蓝饮"及其提取成分表现出较强的干扰NDV增殖和直接杀灭NDV的作用,而阻断作用稍弱。     

漏磁腐蚀检测器新型探头机构的设计

为了解决漏磁腐蚀检测器在管道内检测过程中因探头机构姿态不稳、偏磨及支撑弹簧易折断、易震颤带来的一系列问题,对检测器所用探头机构进行研究,设计制造了一种全新的探头机构.该机构增加了辅助支撑弹簧和柔性连接铰链,很好地解决了传统探头机构存在的不足.该机构的检测探头将以往探头加耐磨层结构变为整体灌装探头壳形式,改善了检测探头的提离值,提高了检测信号的可靠性.与传统探头机构相比,该机构的使用能够有效提高检测数据的可靠性和稳定性.     

辣椒素的抑菌作用及其对某些保护酶活性的影响

 本文对辣椒素的抑菌作用和对寄主体内3种保护酶活性的影响进行了研究,结果表明3.57μg/mL-50.00μg/mL的辣椒素对辣椒枯萎病菌的菌丝生长都有明显的抑制作用,浓度愈高,抑制作用愈强。20μg/mL辣椒素对另外供试的8种病原菌的菌丝具有强烈的抑制作用,其中对番茄灰霉病菌抑制作用最强。辣椒素处理辣椒后1-6 d内,SOD、POD和CAT酶活性的平均增减比率值均明显高于对照,而且对根部和叶部3种保护酶活性的影响显著不同。