Lactobacillus reuteri-fortified camel milk infant formula: Effects of encapsulation,in vitro digestion,and storage conditions on probiotic cell viability and physicochemical characteristics of infant formula

Lactobacillus reuteri fortified camel milk infant formula (CMIF) was produced. The effect of encapsulation in different matrices (sodium alginate and galacto-oligosaccharides) via spray drying, simulated infant gastrointestinal digestion (SIGID), and storage conditions (temperature and humidity) on the viability of L. reuteri in CMIF and the physicochemical properties of CMIF were evaluated. Compared with free cells, probiotic cell viability was significantly enhanced against SIGID conditions upon encapsulation. However, L. reuteri viability in CMIF decreased after 60 d of storage, predominantly at higher storage humidity and temperature levels. At the end of the storage period, significant changes in the color values were observed in all CMIF, with a reduction in their greenness, an increase in yellowness, and a wide variation in their whiteness. Moreover, pH values and caking behavior of all CMIF stored at higher temperature (40°C) and humidity [water activity (a_w) = 0.52] levels were found to be significantly higher than the samples stored under other conditions. Over 30 d of storage at lower humidity conditions (a_w = 0.11 and 0.33) and room temperature (25°C), no significant increase in CMIF lipid oxidation rates was noted. Fourier-transform infrared spectroscopy analysis showed that, compared with the other storage conditions, CMIF experienced fewer changes in functional groups when stored at a_w = 0.11. Microscopic images showed typical morphological characteristics of milk powder, with round to spherical-shaped particles. Overall, camel milk fortified with encapsulated L. reuteri can be suggested as a promising alternative in infant formula industries, potentially able to maintain its physicochemical characteristics as well as viability of probiotic cells when stored at low humidity levels (a_w = 0.11) and temperature (25°C), over 60 d of storage.     

Impact of Divalent Ions on Heavy Oil Recovery by in situ Emulsification

Many reservoir formation brines are characterized by high salinity and contain high concentrations of divalent ions such as calcium, magnesium, and potassium. These challenging conditions can render the surfactants ineffective during chemical flooding for enhanced heavy oil recovery. Various brine types can have an impact on the stability of emulsions generated with chemicals as chemicals have various resistant levels toward hard divalent ions and salinities. To investigate the impact of brine hardness on heavy oil-in-water emulsion stability, glass tube experiments, microscopic visualization and sandpack flooding experiments, and Hele-Shaw visualization experiments were conducted in this study under low-salinity/hard-brine, high-salinity/hard-brine conditions using commercial chemicals, which are designed for specific reservoir brine conditions. Recovery results demonstrated that complex colloidal solution introduced in the previous study with silica and Dodecyltrimethylammonium bromide (DTAB) along with screened chemicals from glass tube tests in this study can enhance heavy oil recovery significantly with an addition of low concentration of xanthan gum (Lee and Babadagli 2018). The results confirmed the robustness of the complex colloidal solution formula to enhance oil recovery with low concentration of polymer under any reservoir brine conditions. The study also demonstrates the potential of polymer as an emulsion stabilization additive for enhanced heavy oil recovery by in situ emulsion generation. Polymer effects seemed to be particularly dominant under the low-salinity conditions than high-salinity conditions.     

基于循证的寒地综合医院的人性化设计研究

鉴于众多国家正在普遍使用循证方式去量化体验指数和指导设计,我国也正开始逐步应用循证设计理论,尝试将研究参与到设计的前期循证和实验及使用后评价的工作中去,文中将处于北方寒冷地域的综合医院为研究对象,对其进行循证评价分析指导设计,通过参照用后评价指标,印证循证指导的人性化设计策略的有效性。     

浅谈工程总承包商对分包商的安全管理

分包商安全能力不足以及总包商安全管理薄弱,已成为导致工程建设项目事故多发的重要原因。将分包商的安全管理有效纳入到总承包商的安全管理体系内,做好分包商的安全管理,对提高总承包商的安全绩效、确保施工安全,具有极其重要的现实意义。从总承包商和分包商两个角度,研究分析分包安全管理中存在的问题及原因,得出分包安全管理各种问题的根源主要是经济利益,管理源头在总承包单位,站在总承包商的视角提出加强分包商安全管理的建议。     

面向流屑角突变建模的切削状态参数经验公式的获得及应用

从提高流屑角突变模型的预测精度出发,建立了切削状态参数与3个切削控制参数之间关系的新经验公式。提出了一种通过迭代法准确设定有限元仿真软件刀-屑摩擦因数的方法,并通过直角切削Al6061-T6工件的有限元仿真试验,获得了一组不同切削控制参数组合条件下的切削状态参数数据。根据该数据拟合出剪切角φ、刀-屑摩擦角β、剪切应力τs关于刀具前角γ0、进给量f和切削速度v的经验公式,并通过一组直角切削试验,验证了所得经验公式的有效性。将新建经验公式应用于流屑角突变建模过程后,所得模型关于突变临界切削宽度的平均预测误差减小了27.2%。     

培养原料种类的减少对人工窖泥发酵剂菌群结构的影响

为实现人工窖泥发酵剂（APMSC）的品质控制，从前期开发的发酵剂配方中分别取出老熟窖泥、曲药、酒糟和黄水初步形成4个简化配方，采用扩增子测序和色谱技术比较了各配方发酵剂的微生物群落结构及香味物质含量差异。结果显示，各配方发酵剂样品中共检测到70个微生物操作分类单元（OTU），其中71.43%为各组样品共有，未检测到独有OTU。各配方样品的优势微生物均存在于其余分组中，仅物种相对丰度有所差异。根据酿酒有益微生物的丰度高低，选择了一种简化配方（无老熟窖泥作原料）发酵剂养护窖池，使酿造白酒的主体香味物质含量得到显著提高。结果表明，即使缺失了某一种培养原料，人工窖泥发酵剂的功能微生物物种也可能由其他原料补充，而原料种类的减少是实现发酵剂品质控制的主要途径。     

武汉市一般人群血清中全氟及多氟烷基化合物浓度及其影响因素研究

目的 了解武汉市一般人群血清中全氟及多氟烷基化合物(PFASs)浓度,探索血清中PFASs浓度水平的影响因素。方法 以在武汉市某医院进行一般体检的人群为研究对象(n=67),通过超高效液相色谱-三重四级杆质谱(UPLC-TQ/MS)联用仪测定外周血清中12种PFASs浓度,采用多元线性回归分析方法分析一般人口学特征和血清中PFASs浓度的关联性。结果 武汉市一般人群血清中12种PFASs的平均浓度水平为11.60 ng/mL。全氟辛烷磺酸及其盐类(PFOS)和全氟辛酸及其盐类(PFOA)的贡献率较大,分别为45.03%和31.86%。男性人群血清中PFOS、PFOA、全氟己基磺酸(PFHxS)、全氟壬酸(PFNA)等主要化合物的浓度高于女性,其β值(95%可信区间)分别为0.708(0.313,1.104)、0.518(0.069,0.967)、0.724(0.388,1.059)和0.684(0.399,0.968)。同时,发现血清中PFOS、PFHxS、PFNA浓度和年龄呈正相关,其β值(95%可信区间)分别为0.062(0.042,0.081)、0.035(0.019,0.052)和0.030(0.016,0.045)。结论 性别和年龄对血清中PFASs浓度有影响,在进行人体PFASs暴露评估中应考虑这些因素。     

对称消声器传递损失测量及误差修正

为了提高对称消声器传递损失的测量效率，基于声学理论分析，提出了一种单负载法传递损失计算模型。针对反射系数较大的吸声末端，导致该方法在实际测量中存在较大误差的问题，推导出了一种能够消除测试管道末端反射声波在上、下游形成多次反射的修正公式。通过自制阻抗管进行试验测试，结果表明：在末端声学负载吸声性能良好的情况下，单负载法传递损失计算模型能够精确计算出对称消声器的传递损失；修正公式能够有效地消除末端负载所引起的反射波对传递损失计算的影响，降低对末端声学负载吸声性能的要求，保证单负载传递损失计算模型的适用性。     

三甘醇脱水填料塔计算方法适用性分析

塔径计算是进行三甘醇填料脱水塔设计的首要工作,为了选用准确适用的塔径计算方法,详细介绍了多种塔径计算方法。以两个实际项目的数据为计算案例,分别采用贝恩-霍根(Bain-Haugen)关联式、通用压降关联图法(GPDC)、塔负荷系数法、Aspen HYSYS软件等不同方法计算三甘醇填料脱水塔的塔径,并进行了计算结果偏差分析和计算方法适用性分析。结果分析表明,塔负荷系数法、通用压降关联图法(GPDC)、Aspen HYSYS软件计算结果相近,经圆整后的塔径一致。贝恩-霍根(Bain-Haugen)关联式算出的结果偏差较大,过于保守,分别为11.11%和8.73%。由于通用压降关联图法(GPDC)的计算结果受GPDC关联图内数据点影响准确度不易保证,建议选用塔负荷系数法和Aspen HYSYS软件进行三甘醇脱水填料塔塔径的计算。      

泰勒公式在不等式中的应用

泰勒公式在高等数学中应用广泛.在简单介绍泰勒公式的基础上，通过具体实例，将泰勒公式（包含佩亚诺型余项、拉格朗日型余项）应用于高阶不等式的证明中，最后对证明步骤及注意事项进行相应分析，以便为学生学习泰勒公式提供参考。