Remote‐Controlled Hydrogel Depots for Time‐Scheduled Vaccination

Remote‐controlled drug depots represent a highly valuable tool for the timely controlled administration of pharmaceuticals in a patient compliant manner. Here, the first pharmacologically controlled material that allows for the scheduled induction of a medical response in mice is described. To this aim, a novel, humanized biohybrid material that releases its cargo in response to a small‐molecule stimulus licensed for human use is developed. The functionality of the material in mice is demonstrated by the remote‐controlled delivery of a vaccine against the oncogenic human papillomavirus type 16. It is shown that the biohybrid depot‐mediated immunoprotection is equivalent to the classical multi‐injection‐based vaccination. These results indicate that this material can be used as a universal remote‐controlled vehicle for the patient‐compliant delivery of vaccines and pharmaceuticals.     

The influence of galactomannans with different amount of galactose side chains on the gelation of soy proteins at neutral pH

The influence of diverse galactomannans, differing mainly on the degree of branching (amount of galactose side chains along the main mannan backbone), on the heat-induced gelation of soybean proteins at pH 7, was investigated using dynamic oscillatory rheological measurements at low strain amplitude and microstructural analysis by confocal laser scanning microscopy. Rheological tests were performed during gel formation, induced by either isothermal heating or by heating/cooling at a constant rate. Two different protein concentrations were analysed, one in the vicinity of the critical gel conditions and the other corresponding to a well developed gel, whereas the galactomannan concentration ranged from 0 to 0.5%. The presence of the galactomannan promoted the gelation to occur for protein concentration below the critical gelation of soybean proteins alone, decreased the gelling temperature and had a positive effect on the gel strength of the heat-induced gels. These effects were more pronounced as the degree of branching decreases. The consequence of demixing and phase separation was dependent on biopolymer concentration and galactomannan branching, resulting in an array of microstructures, spanning emulsion-like, bicontinuous and aggregated morphologies. Structure development within the galactomannan-rich phases, dependent on the branching degree and on the capability of the galactomannan for self-association, may have played a role in the phase separation and viscoelasticity of the final gels. It was demonstrated that by using soybean proteins and galactomannan mixtures at above phase separation concentrations and controlling the polymer concentration and the length of the unsubstituted polysaccharide backbone, tailor-made viscoelasticities and microstructures can be obtained with useful applications in food formulation.     

Prevalence and comparison of Streptococcus infantarius subsp. infantarius and Streptococcus gallolyticus subsp. macedonicus in raw and fermented dairy products from East and West Africa

Streptococcus infantarius subsp. infantarius (Sii) and Streptococcus gallolyticus subsp. macedonicus are members of the Streptococcus bovis/Streptococcus equinus complex (SBSEC) associated with human infections. SBSEC-related endocarditis was furthermore associated with rural residency in Southern Europe. SBSEC members are increasingly isolated as predominant species from fermented dairy products in Europe, Asia and Africa. African variants of Sii displayed dairy adaptations to lactose metabolism paralleling those of Streptococcus thermophilus including genome decay. In this study, the aim was to assess the prevalence of Sii and possibly other SBSEC members in dairy products of East and West Africa in order to identify their habitat, estimate their importance in dairy fermentation processes and determine geographic areas affected by this potential health risk. Presumptive SBSEC members were isolated on semi-selective M17 and SM agar media. Subsequent genotypic identification of isolates was based on rep-PCR fingerprinting and SBSEC-specific16S rRNA gene PCR assay. Detailed identification was achieved through application of novel primers enhancing the binding stringency in partial groES/groEL gene amplification and subsequent DNA sequencing. The presence of S. thermophilus-like lacS and lacZ genes in the SBSEC isolates was determined to elucidate the prevalence of this dairy adaptation. Isolates (n = 754) were obtained from 72 raw and 95 fermented milk samples from Côte d'Ivoire and Kenya on semi-selective agar media. Colonies of Sii were not detected from raw milk despite high microbial titers of approximately 10⁶ CFU/mL on M17 agar medium. However, after spontaneous milk fermentation Sii was genotypically identified in 94.1% of Kenyan samples and 60.8% of Kenyan isolates. Sii prevalence in Côte d'Ivoire displayed seasonal variations in samples from 32.3% (June) to 40.0% (Dec/Jan) and isolates from 20.5% (June) to 27.7% (Dec/Jan) present at titers of 10⁶–10⁸ CFU/mL. lacS and lacZ genes were detected in all Kenyan and 25.8% (June) to 65.4% (Dec/Jan) of Ivorian Sii isolates. Regional differences in prevalence of Sii and dairy adaptations were observed, but no clear effect of dairy animal, fermentation procedure and climate was revealed. Conclusively, the high prevalence of Sii in Kenya, Côte d'Ivoire in addition to Somalia, Sudan and Mali strongly indicates a pivotal role of Sii in traditional African dairy fermentations potentially paralleling that of typical western dairy species S. thermophilus. Putative health risks associated with the consumption of high amounts of live Sii and potential different degrees of evolutionary adaptation or ecological colonization require further epidemiologic and genomic investigations, particularly in Africa.     

Presence of Clostridium difficile in pigs and cattle intestinal contents and carcass contamination at the slaughterhouse in Belgium

The objective of this study was to evaluate the presence of Clostridium difficile in intestinal and carcass samples collected from pigs and cattle at a single slaughterhouse. C. difficile was isolated in 1% and 9.9% of the pig and cattle intestinal contents and in 7.9% and 7% of cattle and pig carcass samples respectively. A total of 19 different PCR-ribotypes were identified, among them types 078 and 014. Seven of 19 ribotypes correlated with the PCR-ribotypes involved in human C. difficile infections in Belgium. This study confirms that animals are carriers of C. difficile at slaughter and ribotypes are identical than those in humans, and that carcass contamination occurs inside the slaughterhouse.     

不同补强剂对氢化丁腈橡胶硫化胶性能的影响

以炭黑(N330)、蒙脱土(MMT)、有机蒙脱土(OMMT)、甲基丙烯酸镁(MgMA)、甲基丙烯酸锌(ZnMA)和齐聚酯等分别作为补强剂,制备相应的HNBR(氢化丁腈橡胶)硫化胶,并对硫化胶的力学性能、耐热老化性能和耐热性等进行了探讨。研究结果表明:ZnMA、MgMA或齐聚酯的综合补强效果相对较好;N330改性HNBR硫化胶的力学性能虽相对较好,但其耐热老化性能相对较差;MMT几乎无补强作用;OMMT能均匀分散在HNBR基体中,其与橡胶分子之间的相容性良好,故相应改性HNBR硫化胶的耐热性和耐热老化性能相对较好。     

Disulfides and Boryl Sulfides Serve as both Initiators and Precatalysts in Radical Reductions of Halides by an N‐Heterocyclic Carbene⋅Borane

Diphenyl disulfide (PhSSPh), a typical boryl monosulfide (diiPr‐Imd‐BH₂SPh) and a typical boryl bis‐sulfide [diMe‐Imd‐BH(SPh)₂] all serve as both initiators and precatalysts in the reduction of alkyl and aryl halides by readily available 1,3‐dimethylimidazol‐2‐ylidene⋅borane (diMe‐Imd‐BH₃). The reactions are suggested to occur by a polarity reverse catalysis mechanism where in situ generated thiophenol is the active catalyst.

     

一种软脂酸镁清净剂的研制

以软脂酸、二氧化碳、活性-60氧化镁为原料合成润滑油类清净剂,实验结果表明,软脂酸质量为5 g,活性-60氧化镁为8 g,甲醇8 mL,70℃反应2 h,可得到碱值为282 mg(KOH)/g的软脂酸镁盐清净剂;红外谱图(IR)显示软脂酸镁清净剂含有无定型的MgCO3。     

三种节能抽油机扭矩特征分析

为了提高抽油机的系统效率,降低能耗,有必要研究一下抽油机的运动轨迹及其扭矩分析,来探究每种抽油机的实用条件。在研究抽油机的结构时,通过对调径变矩、下偏杠铃、悬挂偏置三种节能抽油机的结构计算分析,对比每种抽油机的最大净扭矩、最小负扭矩、均方根扭矩,平均功率,周期载荷系数。调径变距抽油机取消了曲柄平衡,下偏杠铃抽油机改造性强,悬挂偏置抽油机消除负扭矩,减少其扭矩曲线的波动性。所以每种抽油机在在不同的井况下可以不同程度的提高抽油机系统效率。     

不同结构二维光子晶体的带隙特性

应用平面波展开法数值模拟了不同结构二维光子晶体TE模带隙特性,数值模拟得到正方形、正三边形和正六边形圆柱光子晶体结构的TE模带隙特性,比较得到正三边形圆柱结构光子晶体能够形成较宽TE模带隙结构.改变正方形圆柱光子晶体结构形成正方形椭圆柱结构和长方形圆柱结构光子晶体,比较得到长方形圆柱结构光子晶体形成带隙宽度较宽.研究就论为制作TE模滤波器件提供理论参考.