Quantification of reservoir bags as airway pressure-limiting devices in a nonrebreathing system

ObjectiveTo evaluate the influence of reservoir bag types, volumes and previous use on the peak pressures (Pmax) and the times to develop 30 cmH₂O pressure (P30) within a nonrebreathing system with a closed adjustable pressure-limiting (APL) valve.Study designIn vitro study using three-way factorial design with repeated measure on one factor.SubjectsA total of 75 new anesthesia reservoir bags (five types, three volumes, five bags from each type × volume). The bag types were reusable latex (RL), disposable latex (DL) and three disposable neoprene (DN-1, DN-2 and DN-3).MethodsEach bag was tested three times (treatments): new, after prestretching and 1 week later. The bags were attached to a Bain system and anesthesia machine with closed APL valve and patient port with O₂ flow 2 L minute^–1 until Pmax was reached. The Pmax and time to reach P30 values were determined from recorded pressure traces. General linear mixed model analysis was used to examine the effects of bag type, volume and treatment. One-sided 95% upper prediction limits of Pmax were calculated to test the null hypothesis that predicted Pmax of new bags would be ≥ 50 cmH₂O for each factor combination.ResultsRL bags were the least and DN-3 bags were the most compliant. Prestretching increased compliance in all bag types. Smaller bags of RL, DL and DN-1 were less compliant than larger ones. The predicted Pmax values were < 50 cmH₂O only for DN-3 bags after prestretching. The time to reach P30 was critically low when using 0.5 L bags (median 17 seconds).Conclusions and clinical relevanceTo minimize the risk of barotrauma, highly compliant reservoir bags (e.g. DN-3) are recommended and reusable bags should be avoided. Bags should be prestretched before first use, 0.5 L bags should be avoided and fresh gas flow minimized.     

Prevalence of antibodies to bluetongue virus and Anaplasma marginale in Montana yearling cattle entering Alberta feedlots: Fall 2001

A serologic survey was conducted in yearling cattle imported into Alberta feedlots from Montana during October 2001 to estimate the prevalence of antibodies to bluetongue virus (BTV) and Anaplasma marginale in Montana yearling cattle. The apparent prevalence of antibodies to BTV when the competitive enzyme-linked immunosorbent assay (cELISA) was used was 0.37% (21/5608). Test positive cELISA samples were also all positive when tested by virus neutralization (VN) and they reacted to 1 or more BTV serotypes, including 2, 10, 11, 13, and 17. The apparent prevalence of antibodies to A. marginale when a recombinant cELISA (rcELISA) was used with a positive cutoff at 30% inhibition was 1.93% (108/5608). When the rcELISA positive cutoff was at 42% inhibition, the apparent prevalence was 0.73% (41/5608). After the reported sensitivity and specificity of the test had been accounted for, the A. marginale antibody results were consistent with a population that was either free of exposure or had a very low prevalence for A. marginale.     

基于无人机倾斜摄影技术的黄土丘陵区典型小流域淤地坝特征信息提取与分析

淤地坝现状特征信息的精准提取对于淤地坝运行现状评估十分重要,全面的淤地坝特征信息可为病险坝除险加固提供重要依据,当前淤地坝特征信息提取尚缺乏科学高效的技术。针对此问题,拟提出基于无人机倾斜摄影技术提取淤地坝运行现状特征的方法,以无人机航拍影像为基础数据,生成三维实景模型和高精度DEM,用于淤地坝数目、位置、剩余库容、有效坝高等重要现状信息的提取和测量,进而分析小流域内淤地坝分布、组成结构、坝体信息、淤积程度、坝控流域面积等特征。将此技术应用于陕西省榆林市子洲县蛇家沟小流域,详细提取1座大型坝和3座中型坝的现状特征信息。经过同野外实测数据对比,提取的淤地坝坝体信息相对误差均＜3.8%。所识别的大型坝剩余库容不足,处于基本淤满状态,且坝顶明显沉降,在极端降水条件下具有极大的漫顶溃坝风险。坝地耕作面积占小流域面积比例仅为2.17%,仍有坝地尚未开垦利用。研究结果可为小流域淤地坝动态监测与科学管理提供新方法和新思路。     

"Agri-sc免深耕"土壤调理剂在甘蔗上应用试验初报

“Agri-sc免深耕”土壤理剂是国家高科技产品，经在宿根蔗和新植蔗上试验均产生一定的经济效益。其中，在宿根蔗上应用每亩增产0．506吨，净增收67．01元；在新植蔗上应用每亩增产0．309吨，净增收33．92元。经t测验，在宿根蔗上产量差异达显著水平，而在新植蔗上差异不显著。因此，宜在土壤板结较为严重的宿根蔗上推广应用则效果更好。     

汉中市小麦条锈病流行的影响因子及预测模型

为掌握汉中市小麦条锈病流行规律,提高病害测报的科学性和准确性,采用DPS数据处理系统,对多年来汉中市小麦条锈病测报资料进行了主导因素分析,筛选出影响发病程度的主要因子包括小麦感病品种种植比例(x1)、秋苗病田率(x2)、秋苗单位面积平均病叶数(x3)、1月份平均气温(x6)、上年11月份降雨量(x11)、早春病田率(x18)、3月中旬病田率(x19),与发生程度(y)进行逐步回归分析,建立了发病程度预测模型:y=-6.354 7+0.084 0x1+0.022 8x3+0.662 8x6+0.020 9x11,R2=0.968 7。拟合预测符合率为92.31%,相对误差8.96%。利用预测模型对2014-2016年汉中市小麦条锈病进行预测,预测的病级分别为2.93、3.21、1.92,与2014、2015、2016年发生的实际病级3、3、2相吻合。此模型可应用于生产中小麦条锈病的测报。     

Economic feasibility of recirculating aquaculture systems in pangasius farming

This study aims to analyze the economic feasibility of recirculating aquaculture systems (RAS) in pangasius farming in Vietnam. The study uses a capital budgeting approach and accounts for uncertainty in key parameters. Stochastic simulation is used to simulate the economic performance of medium and large farms operating with a traditional system or RAS. Data are obtained through structured surveys and a workshop in the Mekong River Delta. Results show that for large farms, net present value increases from an average of 589,000 USD/ha to 916,000 USD/ha after implementing RAS. Overall, the probability that RAS is a profitable investment is found to be 99% for both farm sizes. With RAS, the crucial parameters determining profitability are price, yield, costs of fingerling, feed, and initial investment. Findings on the robustness of the economic performance of RAS are useful to support public and private decision making towards increasing the sustainability of pangasius production.     

Osteogenic proliferation and differentiation of canine bone marrow and adipose tissue derived mesenchymal stromal cells and the influence of hypoxia

The aim of this study was to compare the osteogenic and proliferative potential of canine mesenchymal stromal cells (cMSCs) derived from bone marrow (BM-cMSCs) and adipose tissue (AT-cMSCs). Proliferation potential was determined under varying oxygen tensions (1%, 5%, and 21% O(2)). Effects of reduced oxygen levels on the osteogenic differentiation of AT-cMSCs were also investigated. AT-cMSCs proliferated at a significantly faster rate than BM-cMSCs, although both cell types showed robust osteogenic differentiation. Culture in 5% and 1% O(2) impaired proliferation in cMSC from both sources and osteogenic differentiation in AT-cMSCs. Our data suggests that AT-cMSCs might be more suitable for use in a clinical situation, where large cell numbers are required for bone repair, due to their rapid proliferation combined with robust osteogenic potential. Our data also suggests that the inhibitory effects of hypoxia on both cell proliferation and differentiation should be considered when using MSCs in a potentially hypoxic environment such as a fracture site.     

地表覆盖方式对桃果实发育过程中果实品质指标的影响

采用信阳五月鲜桃为试验材料,设置覆膜和覆膜+覆秸秆(膜+秸秆)两种地表覆盖栽培方式,以清耕(CK)为对照,测定桃果实发育过程中可溶性糖、可滴定酸、可溶性固形物、花青苷含量的动态变化,研究不同地表覆盖方式对信阳五月鲜桃果实生长发育的影响。结果表明:两种地表覆盖方式下,信阳五月鲜桃果实发育过程中可溶性固形物、花青苷、可溶性糖含量变化均为前期上升趋势缓慢,盛花期78d后迅速增加;而桃果实中可滴定酸含量随着果实成熟度的增加而逐渐降低。信阳五月鲜桃果实成熟期(盛花期后93d),覆膜处理的桃果实中的可滴定酸含量较低,可溶性固形物、花青苷和可溶性糖含量较高,与CK和膜+秸秆处理相比差异显著;膜+秸秆处理的桃果实中花青苷含量与CK相比显著增加。信阳五月鲜桃果实发育过程中果实中可溶性固形物、花青苷、可溶性糖含量之间分别存在显著正相关,并均与可滴定酸含量呈显著负相关。总之,桃果实品质指标在果实发育过程中存在显著相关性,并且在果实成熟期迅速变化;桃树生产上应用单一覆膜能显著提高果实品质。