Shear wave elastography evaluation of cats with chronic kidney disease

Chronic kidney disease (CKD) is a major health condition in cats that can lead to poor quality of life and financial implications for therapy. Currently staging and identification of CKD is limited by diagnostic testing such as creatinine and urine-specific gravity, which do not change until late in the disease course. Other methods to evaluate CKD would be valuable in the clinical setting. Shear wave elastography is one novel ultrasound method, which has shown promise in identifying increases in tissue stiffness and identifying CKD in people. As CKD is often histologically characterized by tubulointerstitial fibrosis, shear wave elastography has the potential to identify CKD and differentiate between stages of CKD in cats. This prospective observational case-control study with 78 cats found no difference in shear wave velocities between groups (P = 0.33), a contradictory finding to one prior publication. There was no effect of weight (P = 0.65), nor the presence of mineralization (P = 0.31) or infarction (P = 0.52) on cortical shear wave velocities. There was a significant effect of age on shear wave velocity (P = 0.018) where velocities increased with age. The intraclass correlation coefficient was only moderate (0.62). Possible reasons for the difference in results between our work and that published prior, include differences in methodology and differences in instrumentation. Variability in measurements in our population may be due to the effects of respiratory motion or limitations in shear wave elastography software. As such, shear wave elastography is not currently recommended as a tool to evaluate CKD in cats and further work is necessary.     

Diagnostic accuracy of electrocardiography and thoracic radiography in the assessment of left atrial size in cats: comparison with transthoracic 2-dimensional echocardiography

BACKGROUND: Left atrial (LA) enlargement (LAE) is a morphologic expression of the severity and chronicity of left ventricular (LV) diastolic dysfunction, volume overload, and increased atrial pressure and has diagnostic, therapeutic, and prognostic importance in cats. The noninvasive gold standard for assessing LA size is 2-dimensional echocardiography (2DE). HYPOTHESIS: ECG and thoracic radiography may be used to predict LAE in cats. ANIMALS: Twenty-one healthy control cats and 31 cats with cardiomyopathy were prospectively studied. METHODS: 2DE studies, including determination of the maximum LA dimension (LAD) and area (LAA), were performed prospectively in all cats and compared to the assessment of LA size based on thoracic radiography and indices obtained from a 6-lead ECG. Results obtained from healthy cats were used to generate discrimination limits suggestive of LAE as defined by LAD > 1.57 cm and LAA > 2.75 cm2. RESULTS: In cats with LAE, P wave duration and PR interval were prolonged and radiographic LA vertebral heart size (LA-VHS) was increased (P < .05). P wave-related indices had low sensitivity (Se; range, 0.12 to 0.60) but high specificity (Sp; range, 0.81 to 1.00) for the prediction of LAE. Radiographic indices had low Se (range, 0.28 to 0.72) and high Sp (range, 0.74 to 0.95) for the prediction of LAE. Correlation analyses identified correlations between LAA and P wave duration (r = 0.47, P = .003) and LAD and LA-VHS (r = 0.70, P < .001). CONCLUSION AND CLINICAL IMPORTANCE: ECG and thoracic radiography are reasonably specific but less sensitive predictors of LAE in cats.     

基于Maple系统的Riccati方程自动求解的实现

利用非线性演化方程的精确行波解的手工推导和计算的原理,结合计算机符号计算,在计算机代数系统Maple上,开发了基于非线性代数方程组吴文俊消元法的非线性演化方程精确行波解的自动求解软件包,实现了非线性方程(组)的求解过程的完全自动化。     

Electrocardiographic indicators of excitability in horses for predicting recovery quality after general anaesthesia

ObjectiveTo determine whether preoperative electrocardiographic measurements linked to sympathetic nervous activity could be used to predict recovery quality after general anaesthesia in horses.Study designProspective, clinical study.AnimalsEighteen adult client-owned horses.MethodsThe electrocardiogram (ECG) was recorded presurgery in horses under three standard conditions: stabled unattended; with a groom whilst being led along a standard course; alone in the induction box. After surgery, each animal's recovery quality was scored by eight experienced anaesthetists or technicians using Donaldson's scoring system (2000). The digitized ECG recordings were analyzed for T-wave morphology, mean heart rate (HR), HR variability (HRV) and HRV derivatives including mean R-R interval, standard deviation of normal intervals (SDNN) and the root mean square of successive intervals (RMSSD), low (LF) and high frequency (HF) activity and the LF/HF ratio in both fast Fourier transformed and autoregressive spectra. Correlations between ECG variables and recovery score were examined using Spearman's rank correlation.ResultsThere was no significant correlation between preanaesthetic ECG measurements and recovery quality.ConclusionsPredictions of recovery quality after general anaesthesia in horses cannot be based on preanaesthetic ECG variables.Clinical relevanceMeasures other than those based on the ECG should be investigated as predictors of recovery quality.     

分光光度法测定薄荷叶中总黄酮含量的研究

通过乙醇浸提,超声波提取,采用亚硝酸钠—硝酸铝分光光度法测定薄荷叶中总黄酮立此法。测定过程中,以芦丁为对照标准品,确定了最大吸收波长为510nm,以芦丁的吸光度和浓度制作标准曲线,得回归方程：y=0.4833x-0.0001,R2=0.9997,样品在浓度为0.010～0.996mg/mL范围内线性良好;测定薄荷叶的总黄酮含量平均值为3.04%;加样回收率为99.81%,RSD为0.97%。该测定方法操作简便,结果准确,重复性、稳定性皆好。     

超声提取技术在中药中的研究进展

目的：介绍超声提取的原理和在中药提取方面的研究概况。方法：查阅、分析近些年来超声技术在中药提取方面的研究文献。结果：超声提取技术在中药领域中应用广泛,可用于药材中黄酮类、生物碱类、多糖类等的提取,超声提取中药的工艺研究较为丰富,但仍需完善。结论：超声提取技术是一种省时、节能、提取效率高的新方法,在中药提取中具有广阔的应用前景和开发价值。     

野外长期污染土壤中残留多环芳烃的提取

[目的]准确定量野外污染土壤中残留的PAHs,为PAHs污染土壤的修复提供依据。[方法]针对长期石油污水灌溉农田土壤,对比了常用PAHs提取方法（索氏、震荡和超声提取方法）的提取效率差异。[结果]索氏提取法对土壤中总PAHs的可提取量最高（6873.7μg/kg）,其次为往复震荡提取法（6698.8μg/kg）,超声提取法最低（5737.6μg/kg）,约为前2种提取方法的84%左右;相对于其他提取方法,索氏提取对4环和6环PAHs的提取效率最高,震荡提取对2环和5环PAHs的提取效率最高,超声萃取仅对3环PAHs提取效率最高。[结论]该研究为野外污染土壤中残留PAHs定量评价方法的选择提供了技术支持。     

单轴加载下混凝土超声波与声发射联合特性试验研究

本研究通过混凝土试件在单轴向受压下的试验研究,对比了不同强度等级立方体和棱柱体试件对超声波波速的影响,分析超声波及声发射参数随应力的变化关系。试验结果表明:强度等级越高的混凝土超声波波速时间稳定性表现越好;棱柱体超声波稳定性优于立方体试件;在工作应力为极限破坏应力的20%~70%阶段,超声波波速下降缓慢,声发射撞击数增加,能量和振铃计数呈突发式增长;当工作应力大于混凝土的极限破坏应力70%后,超声波波速明显下降,声发射活动急剧增加。提出划分应力阶段对2种检测方法进行分析,为混凝土结构工作应力状态的检测提供参考。     

超声辅助纤维素酶提取茶粕中茶皂苷的工艺研究

[目的]优化茶粕中茶皂苷的提取工艺。[方法]在纤维素酶作用下,利用超声辅助,通过单因素试验与正交试验,研究料液比、酶解温度、酶解时间、酶的用量等因素对茶皂苷提取得率的影响。[结果]试验表明,茶粕中茶皂苷的最佳提取条件为酶解温度50℃,酶添加量0.3%,酶解时间70 min,料液比1∶20(g∶m L),在此条件下茶皂苷提取得率为9.769%。[结论]采用超声辅助纤维素酶提取,可有效提高茶粕中茶皂苷的提取得率。     

超声波提取醉马草中生物碱的研究

[目的]研究醉马草中生物碱的超声提取工艺。[方法]采用40 kHz超声波水处理醉马草草粉,水提去渣得到滤液后,分别用氯仿、乙酸乙酯、正丁醇萃取,在回收溶剂的情况下用减压蒸馏获取生物碱,经薄层层析和红外鉴定。[结果]正交试验选取各因素的最佳水平组合为A1B2C2D2,即最佳提取工艺条件为以料液比1∶7.5（g/ml）、温度60℃、超声功率250 W,超声时间60 min;在此条件下生物碱的提取率为2.06 mg/g;新草的生物碱的提取率为14.04 mg/g。结构鉴定结果显示,醉马草混合碱中含有苦马豆素。[结论]该方法快速有效,准确度高,可用于醉马草中生物碱的提取。