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101.
采用冲击钻进行桩基础钻孔施工,经常会出现入岩倾斜偏位的现象,如果处理不当,就会造成 废桩。这里介绍一种简单而有效的处治方法——用混凝土封底法,针对这种现象进行处理。 相似文献
102.
N.J. Cave S.T. Koo 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(3):781-785
Background
Electrochemical approach to the assessment of acid‐base states should provide a better mechanistic explanation of the metabolic component than methods that consider only pH and carbon dioxide.Hypothesis/Objectives
Simplified strong ion equation (SSIE), using published dog‐specific values, would predict the measured serum pH of diseased dogs.Animals
Ten dogs, hospitalized for various reasons.Methods
Prospective study of a convenience sample of a consecutive series of dogs admitted to the Massey University Veterinary Teaching Hospital (MUVTH), from which serum biochemistry and blood gas analyses were performed at the same time. Serum pH was calculated using the SSIE, and published values for the concentration and dissociation constant for the nonvolatile weak acids (Atot and K a), and subsequently was compared with the dog''s actual pH . To determine the source of discordance between and , the calculations were repeated using a series of substituted values for Atot and K a.Results
The did not approximate the for any dog (P = 0.499, r 2 = 0.068), and was consistently more basic. Substituted values Atot and K a did not significantly improve the accuracy (r 2 = 0.169 to <0.001). Substituting the effective SID produced a strong association between and (r 2 = 0.977).Conclusions and clinical importance
Using the simplified strong ion equation and the published values for Atot and K a does not appear to provide a quantitative explanation for the acid‐base status of dogs. Efficacy of substituting the effective SID in the simplified strong ion equation suggests the error lies in calculating the SID. 相似文献103.
Assessing the influence of mechanical ventilation on blood gases and blood pressure in rattlesnakes
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Mads F Bertelsen Rasmus Buchanan Heidi M Jensen Cleo AC Leite Augusto S Abe Søren S Nielsen Tobias Wang 《Veterinary anaesthesia and analgesia》2015,42(4):386-393
ObjectiveTo characterize the impact of mechanical positive pressure ventilation on heart rate (HR), arterial blood pressure, blood gases, lactate, glucose, sodium, potassium and calcium concentrations in rattlesnakes during anesthesia and the subsequent recovery period.Study designProspective, randomized trial.AnimalsTwenty one fasted adult South American rattlesnakes (Crotalus durissus terrificus).MethodsSnakes were anesthetized with propofol (15 mg kg−1) intravenously, endotracheally intubated and assigned to one of four ventilation regimens: Spontaneous ventilation, or mechanical ventilation at a tidal volume of 30 mL kg−1 at 1 breath every 90 seconds, 5 breaths minute−1, or 15 breaths minute−1. Arterial blood was collected from indwelling catheters at 30, 40, and 60 minutes and 2, 6, and 24 hours following induction of anesthesia and analyzed for pH, PaO2, PaCO2, and selected variables. Mean arterial blood pressure (MAP) and HR were recorded at 30, 40, 60 minutes and 24 hours.ResultsSpontaneous ventilation and 1 breath every 90 seconds resulted in a mild hypercapnia (PaCO2 22.4 ± 4.3 mmHg [3.0 ± 0.6 kPa] and 24.5 ± 1.6 mmHg [3.3 ± 0.2 kPa], respectively), 5 breaths minute−1 resulted in normocapnia (14.2 ± 2.7 mmHg [1.9 ± 0.4 kPa]), while 15 breaths minute−1 caused marked hypocapnia (8.2 ± 2.5 mmHg [1.1 ± 0.3 kPa]). Following recovery, blood gases of the four groups were similar from 2 hours. Anesthesia, independent of ventilation was associated with significantly elevated glucose, lactate and potassium concentrations compared to values at 24 hours (p < 0.0001). MAP increased significantly with increasing ventilation frequency (p < 0.001). HR did not vary among regimens.Conclusions and clinical relevanceMechanical ventilation had a profound impact on blood gases and blood pressure. The results support the use of mechanical ventilation with a frequency of 1–2 breaths minute−1 at a tidal volume of 30 mL kg−1 during anesthesia in fasted snakes. 相似文献
104.
105.
猪在农业和医学领域均具有重要应用价值,利用基因修饰技术能够快速提高猪的经济性状和培育
人类疾病动物模型。CRISPR/Cas9 基因编辑技术具有操作简单、高效和低成本的优势,在猪基因修饰领域具有重
要应用。但 CRISPR/Cas9 易引发基因组结构不稳、大范围染色体重排和基因脱靶等问题,因而具有潜在的生物
安全风险。近年基于 CRISPR/Cas9 开发的碱基编辑技术可以实现单个碱基定向转换,不会导致 DNA 双链断裂,
理论上不会引发插入 / 缺失(Indels),对基因编辑更精准、更安全。随着碱基编辑工具的不断开发和改良,其
不仅能产生 C → T(A → G)突变,还能产生 C、A 两种碱基的同时突变以及 C → G 突变,增加了应用范围;改
良的碱基编辑工具在保持编辑效率的同时能够降低甚至消除旁侧突变、非 C → T(A → G)突变以及 Indels,使
得碱基编辑技术在猪遗传修饰上具有更加重要的潜在应用价值。综述了不同的碱基编辑系统原理、碱基编辑技
术在基因修饰猪模型构建和猪遗传改良中的应用,以及碱基编辑系统在猪成纤维细胞中的编辑效率和脱靶情况,
以期为开展猪碱基编辑应用实践提供参考。 相似文献
106.
107.
土壤养分含量同海拔高度密切相关,为探索湖北巴东县茶店子基地单元不同海拔植烟土壤的理化性状,更好地指导巴东烟叶生产实践工作,对巴东县茶店子基地单元不同海拔植烟土壤的理化性状进行了分析。结果表明:(1)海拔800m以下区域,植烟土壤理化性状特点是pH值、有机质、氮素、全磷含量处于适宜标准或以上,但速效磷和钾素含量较低;(2)800~1200m区域,土壤pH值、氮素含量较为适宜,土壤有机质含量普遍偏高,但是磷素、钾素含量较低;(3)1200m以上区域,除土壤pH值偏低以外,其他指标均处于优质烟叶生产范围内或高于标准。结合茶店子基地单元烟叶种植区划目标,建议在生产上采取“控氮、增磷、补钾”的施肥策略,施用充分腐熟的优质有机肥和适量土壤改良剂改良土壤,提高土壤养分利用率,进一步提高烟叶产量和质量。 相似文献
108.
109.
在国家要求加快推进现代种业发展的形势下,地处浙西南山区的遂昌,利用当地生态资源,以注重强化组织领导、注重管理机制创新、注重科技攻关、注重质量监管、注重扶持激励等为举措,合力建设水稻制繁种基地县。 相似文献
110.
为实现滚动轴承复合故障自适应诊断,该研究提出了基于循环含量比-归一化谐波比例(Ratio of Cyclic Content-Normalized Proportion of Harmonics,RCC-NPH)融合指标改进的最大二阶循环平稳盲解卷积(Maximum second order cyclostationary blind deconvolution,CYCBD)方法。首先,构建了RCC-NPH融合指标,解决了CYCBD算法循环频率确定依赖先验知识及遍历所有故障频率空间耗时的问题。其次,根据RCC-NPH融合指标图估计CYCBD的循环频率集,实现了CYCBD参数的自适应选择。再次,采用自适应参数CYCBD方法对输入信号进行解卷积运算,提取了不同循环频率对应的故障信号。最后,对提取的故障信号进行Hilbert包络解调分析,完成故障的辨识。利用该方法分别对仿真信号和轴承复合故障信号进行试验,均能有效检测信号中包含的故障成分,实现了复合故障的自适应诊断。与其他指标相比,该方法能够有效避免噪声和谐波的干扰,适用于复合故障诊断。 相似文献