Allergic reactions to raw, pasteurized, and homogenized/pasteurized cow milk: a comparison

Five children aged 12-40 months with IgE-mediated adverse reactions to cow milk (immediate onset clinical pattern of cow milk allergy) were orally challenged double-blind in random order with three different milk preparations processed from the same batch of milk 1) raw untreated cow milk, 2) pasteurized cow milk, 3) homogenized and pasteurized cow milk, and 4) Nutramigen (a commercial hypoallergenic infant formula based on hydrolysed casein) as placebo. Skin prick tests with the same preparations were also performed. On oral challenge the three different processed milk types provoked significant and similar allergic reactions in each child, and no adverse reactions followed the challenge with placebo (Nutramigen). Skin prick test with the same milk products were positive in all children and comparable to the results with an extract of purified raw cow milk protein (Soluprick), whereas Nutramigen did not elicit any skin reactions. A tendency towards a lower threshold of reaction and larger skin reactions induced by the processed milk preparations might indicate an increased ability of pasteurized and homogenized/pasteurized milk to evoke allergic reactions in patients allergic to milk.     

基于“药辅合一”理念的Pickering乳技术提升儿科用药羚珠散中石菖蒲挥发油热稳定性的研究

目的 在“药辅合一”理念下导入Pickering乳技术,提升儿科用药羚珠散中石菖蒲挥发油的稳定性。方法 对羚珠散各饮片粉末进行初步表征,确定稳定剂。通过成乳量、包油量和乳剂形态筛选出最佳稳定剂质量浓度、油水比和制备方法。并使用近红外光谱（nearinfraredspectroscopy,NIRS）分析石菖蒲油在Pickering乳中的包裹状态。比较不同时间下各组别挥发油的保有量、丙二醛和过氧化物的含量。再通过GC-MS分析其中成分的变化趋势。结果 筛选出珍珠粉作为Pickering乳的稳定剂,珍珠粉质量浓度为65 mg/mL,油水比9∶11为最优成乳条件,高压均质法为最优的制备方法,NIRS分析可知石菖蒲挥发油被珍珠粉包裹,Pickering乳液中没有形成新的化学键。对比各组在不同时间段下石菖蒲油的保有率和其中丙二醛和过氧化物含量,可知40℃放置1、3、8 h的Pickering乳剂相比于石菖蒲挥发油组有更高的保有率和更低的氧化程度。GC-MS分析结果表明,相比于石菖蒲挥发油组,Pickering乳组挥发性成分的稳定性显著提高。结论 在“药辅合一”理念下Pickering乳可用于含油固...     

以茶皂素为天然乳化剂制备水飞蓟素纳米乳及其理化性质考察

目的 以茶皂素为天然乳化剂制备水飞蓟素纳米乳（silymarin nanoemulsion,SM-NE）。方法 使用高速剪切联合高压均质法制备SM-NE,以平均粒径、粒度多分散系数（polydispersity index,PDI）、分层指数和外观为主要评价指标,采用单因素试验对处方和制备工艺进行优化;以摩尔增溶比（molar solubilization ratio,MSR）和胶束-水分配系数（K_m）作为评价指标探究了茶皂素对水飞蓟素的增溶能力;对最佳处方和工艺制备的SM-NE进行了理化性质和稳定性考察。结果 SM-NE的最佳处方为水飞蓟素用量0.15%,茶皂素用量为0.3%,油相用量为5%,最佳制备工艺为剪切速率16 000 r/min,剪切时间3 min,均质压力为100 MPa,均质次数为8次;茶皂素对水飞蓟素增溶参数值MSR和K_m分别为0.011 1和2.31;制得的SM-NE的平均粒径为（204.1±2.8）nm,PDI为0.058±0.007,电导率为（117.8±0.9）μs/cm,pH值为7.31±0.10,浊度为（59.75±1.10）cm^-1,水飞蓟素溶解度为（1.22±0.05）mg/mL;稳定性结果显示,SM-NE具有良好的离心稳定性和储存稳定性。结论 以茶皂素为天然乳化剂成功制备了稳定的SM-NE,茶皂素是一种潜在的用于水飞蓟素新型绿色纳米制剂生产的天然增溶剂。     

Stochastic Multiscale Heat Transfer Analysis of Heterogeneous Materials with Multiple Random Configurations

This study presents a new stochastic multiscale analysis approach to analyze the heat transfer performance of heterogeneous materials with random structures at different length scales. The heterogeneities of the materials are taken into account by periodic layouts of unit cells, consisting of randomly distributed inclusion dispersions and homogeneous matrix on the microscale and mesoscale. Based on the reiterated homogenization, a novel unified micro-meso-macro stochastic multiscale formulation is established and the scale gap is correlated by means of two-scale asymptotic expansions. Also, the stochastic multiscale formulae for computing the effective thermal property and temperature field are derived successively. Then, the stochastic prediction algorithm coupled with the finite element method is brought forward in details. The accuracy of the implemented stochastic multiscale analysis is verified by comparing the results against the experimental data for three scales heterogeneous materials with several different material combinations. The comparison demonstrates the usability of the proposed stochastic multiscale method for the determination of the thermal behaviors. This study offers a unified multiscale framework that enables heat transfer behavior analysis of heterogeneous materials with multiple random configurations.     

Influence of Boundary Conditions on Numerical Homogenization of High Performance Concrete

Concrete is the most widely used construction material nowadays. We are concerned with the computational modelling and laboratory testing of high-performance concrete (HPC). The idea of HPC is to enhance the functionality and sustainability of normal concrete, especially by its greater ductility as well as higher compressive, tensile, and flexural strengths. In this paper, the influence of three types (linear displacement, uniform traction, and periodic) of boundary conditions used in numerical homogenization on the calculated values of HPC properties is determined and compared with experimental data. We take into account the softening behavior of HPC due to the development of damage (micro-cracks), which finally leads to failure. The results of numerical simulations of the HPC samples were obtained by using the Abaqus package that we supplemented with our in-house finite element method (FEM) computer programs written in Python and the homogenization toolbox Homtools. This has allowed us to better account for the nonlinear response of concrete. In studying the microstructure of HPC, we considered a two-dimensional representative volume element using the finite element method. Because of the random character of the arrangement of concrete’s components, we utilized a stochastic method to generate the representative volume element (RVE) structure. Different constitutive models were used for the components of HPC: quartz sand—linear elastic, steel fibers—ideal elastic-plastic, and cement matrix—concrete damage plasticity. The numerical results obtained are compared with our own experimental data and those from the literature, and a good agreement can be observed.     

Optimal Design of Double-Walled Corrugated Board Packaging

Designing corrugated board packaging is a real challenge, especially when the packaging material comes from multiple recycling. Recycling itself is a pro-ecological and absolutely necessary process, but the mechanical properties of materials that are processed many times deteriorate with the number of cycles. Manufacturers are trying to use unprecedented design methods to preserve the load-bearing capacity of packaging, even when the material itself is of deteriorating quality. An additional obstacle in the process of designing the structure of paper packaging is the progressive systematic reduction of the grammage (the so-called lightweight process) of corrugated cardboard. Therefore, this research presents a critical look at the process of optimal selection of corrugated cardboard for packaging structures, depending on the paper used. The study utilizes analytical, simplified formulas to estimate the strength of cardboard itself as well as the strength of packaging, which are then analyzed to determine their sensitivity to changes in cardboard components, such as the types of paper of individual layers. In the performed sensitivity analysis, numerical homogenization was used, and the influence of initial imperfections on the packaging mechanics was determined. The paper presents a simple algorithm for the optimal selection of the composition of corrugated cardboard depending on the material used and the geometry of the packaging, which allows for a more conscious production of corrugated cardboard from materials derived, e.g., from multiple recycling.     

Parametric Optimization of Thin-Walled 3D Beams with Perforation Based on Homogenization and Soft Computing

The production of thin-walled beams with various cross-sections is increasingly automated and digitized. This allows producing complicated cross-section shapes with a very high precision. Thus, a new opportunity has appeared to optimize these types of products. The optimized parameters are not only the lengths of the individual sections of the cross section, but also the bending angles and openings along the beam length. The simultaneous maximization of the compressive, bending and shear stiffness as well as the minimization of the production cost or the weight of the element makes the problem a multi-criteria issue. The paper proposes a complete procedure for optimizing various open sections of thin-walled beam with different openings along its length. The procedure is based on the developed algorithms for traditional and soft computing optimization as well as the original numerical homogenization method. Although the work uses the finite element method (FEM), no computational stress analyses are required, i.e., solving the system of equations, except for building a full stiffness matrix of the optimized element. The shell-to-beam homogenization procedure used is based on equivalence strain energy between the full 3D representative volume element (RVE) and its beam representation. The proposed procedure allows for quick optimization of any open sections of thin-walled beams in a few simple steps. The procedure can be easily implemented in any development environment, for instance in MATLAB, as it was done in this paper.     

Study on the Shear Modulus Based Equivalent Homogenization Methods of Multi-Layer BCC Lattice Sandwich

In this paper, the shear modulus based equivalent homogenization methods of multi-layer BCC (body-centered cubic) lattice sandwich structures have been studied using analytical, experimental, and finite element methods. In the analytical approach, the multiple strut-deformation patterns were introduced in the derivations of the shear modulus based on Euler–Bernoulli beam theory and Timoshenko beam theory according to different boundary conditions. The analytical shear modulus of three types of rectangle shaped sandwich BCC lattice structures was derived. Finite element models of the BCC lattice structures by ANSYS were conducted to estimate the analytical solutions. Butterfly style sandwich BCC lattice structures were printed by SLM technology using 304 stainless steel (06Cr19Ni10), and corresponding shear experiments using modified Arcan Rig experimental devices were conducted to validate the analytical and numerical calculations. Good agreements were observed among the analytical, numerical, and experimental results.     

利用微透析技术进行青藤碱贴剂的生物等效性研究

目的：研究不同制剂工艺的青藤碱凝胶贴剂的生物等效性，探讨微透析技术在生物等效性研究中的可行性和优越性。方法：以不同工艺制备青藤碱的普通凝胶贴剂和脂质体凝胶贴剂，以裸鼠为实验动物进行经皮给药后，分别采用组织匀浆法及微透析法对青藤碱的体内药量的进行测定。结果：组织匀浆法的测定结果显示出经过20h以上的时间后，脂质体凝胶贴剂比普通凝胶贴剂具有更高的皮肤局部剩余药量；而微透析法的检测结果则显示出在整个测定过程中，脂质体凝胶贴剂比普通凝胶贴剂具有更高的皮肤局部瞬间药量，且皮肤局部药时曲线与国际上报道的大多数经皮吸收情况相符。结论：青藤碱的脂质体凝胶贴剂比普通凝胶贴剂具有更高的局部生物利用度，且脂质体可能存在贮库效应；微透析技术可用于制剂的生物利用度及生物等效性研究。     

2种方法制备银杏内酯长循环固体脂质纳米粒的比较

目的:研究银杏内酯AB长循环固体脂质纳米粒(GAB-LSLN)的制备方法,并探讨GAB-LSLN的主要理化性质。方法:分别采用超声法和高压乳匀法制备GAB-LSLN。在电镜下观察其形态,测定其粒径、Zeta电位和包封率,并在室温下放置4周,观察GAB-LSLN的稳定性。结果:超声法制备的GAB-LSLN在透射电镜下呈片状存在,形态不规则;高压乳匀法制备的GAB-LSLN呈球状,形态规则。超声法和高压乳匀法制备的GAB-LSLN粒径分别为(219.6±14.3)nm和(173.9±10.4)nm(P<0.001);Zeta电位分别为(—21.12±1.03)mv和(—27.43±2.14)mV(P<0.001),包封率分别为(85.05±0.67)%和(92.49±0.88)%(P<0.001)。高压乳匀法制备的GAB-LSLN室温放置4周后,粒径无显著增加(P>0.05)。结论:高压乳匀法制备GAB-LSLN具有粒径小、稳定性和包封率高的特点,优于超声法。