Statistical Mechanical Treatments of Protein Amyloid Formation

Protein aggregation is an important field of investigation because it is closely related to the problem of neurodegenerative diseases, to the development of biomaterials, and to the growth of cellular structures such as cyto-skeleton. Self-aggregation of protein amyloids, for example, is a complicated process involving many species and levels of structures. This complexity, however, can be dealt with using statistical mechanical tools, such as free energies, partition functions, and transfer matrices. In this article, we review general strategies for studying protein aggregation using statistical mechanical approaches and show that canonical and grand canonical ensembles can be used in such approaches. The grand canonical approach is particularly convenient since competing pathways of assembly and dis-assembly can be considered simultaneously. Another advantage of using statistical mechanics is that numerically exact solutions can be obtained for all of the thermodynamic properties of fibrils, such as the amount of fibrils formed, as a function of initial protein concentration. Furthermore, statistical mechanics models can be used to fit experimental data when they are available for comparison.     

Control of the state of a bubbling fluidised bed

Bubbling fluidised beds are used for a wide variety of industrial processes. As such it is desirable to be able to specify the conditions within the bed. These conditions can be subject to unwanted change in areas such as feedstock or fluctuations in process settings such as gas flow. This paper shows how pressure measurements can be used to characterise changing conditions within a three-dimensional bubbling fluidised bed. These characterisation techniques are then used to show that a linear controller can control the conditions within a bubbling bed. This control is demonstrated to be robust, being insensitive to the gas flow conditions, controller gains and location at which the characterisation measurement is made.     

Synthetic Biology Approaches in the Development of Engineered Therapeutic Microbes

Since the intimate relationship between microbes and human health has been uncovered, microbes have been in the spotlight as therapeutic targets for several diseases. Microbes contribute to a wide range of diseases, such as gastrointestinal disorders, diabetes and cancer. However, as host-microbiome interactions have not been fully elucidated, treatments such as probiotic administration and fecal transplantations that are used to modulate the microbial community often cause nonspecific results with serious safety concerns. As an alternative, synthetic biology can be used to rewire microbial networks such that the microbes can function as therapeutic agents. Genetic sensors can be transformed to detect biomarkers associated with disease occurrence and progression. Moreover, microbes can be reprogrammed to produce various therapeutic molecules from the host and bacterial proteins, such as cytokines, enzymes and signaling molecules, in response to a disturbed physiological state of the host. These therapeutic treatment systems are composed of several genetic parts, either identified in bacterial endogenous regulation systems or developed through synthetic design. Such genetic components are connected to form complex genetic logic circuits for sophisticated therapy. In this review, we discussed the synthetic biology strategies that can be used to construct engineered therapeutic microbes for improved microbiome-based treatment.     

螯合性表面活性剂的制备工艺与应用性能(Ⅳ)——N-酰基ED3A的应用

介绍了N-酰基ED3A螯合性表面活性剂与其他表面活性剂优异的配伍性能,复配产品能明显提高混合体系的耐盐性和抗硬水性,与酶、漂白剂相容性好,具有一定的助溶能力,适于配制无磷、超浓缩重垢液体洗涤剂、香波、浴液等个人清洁用品。重点介绍了此类表面活性剂的典型品种月桂酰基ED3A钠盐优异的表面活性与较强的螯合能力,它可以牢固地吸附在金属表面,抑制低碳钢在酸性条件下的腐蚀速度,使不锈钢在碱性条件下表面钝化,非常适于配制金属清洗剂、家具清洗剂等硬表面清洗剂,还可用于工业清洗、电渡、乳液聚合、浮选等领域。     

The concept of a near-field Raman probe

This article considers the possibility to use tips, which are functionalised by Raman active molecules, as new Raman probes for near-field optics in such a way that the Raman spectrum can be recorded of such a tip. If the Raman spectrum of the probe molecules is sensitive to their immediate environment, the probe can be used to map a surface by its local influence on the Raman spectrum of the probe. This new concept may be very promising for the investigation of specific interactions at the nanoscale by an optical response. Examples of the sensitivity of such a probe to the local environment are presented as a basis for further development of such a probe.     

Synthesis of secondary ethers derived from meadowfoam oil

Secondary ethers can be obtained from meadow-foam-derived delta lactones or 5-hydroxy fatty acids by using Lewis or Brønsted acid catalysts in good yield (70–90%). The conversion of δ-lactone or 5-hydroxy fatty acid to 5-ethers is performed under atmospheric pressure between 67 and 125°C with 0.5–6.4 mole equivalents of acid catalyst in the presence of 2–40 equivalents of alcohol and a reaction time of 1–140 h. Acid catalysts include mineral acids, such as perchloric and sulfuric; Lewis acids, such as boron trifluoride; and heterogeneous catalysts, such as clays and ion-exchange resins. Primary alcohols, such as methanol, butanol, decanol, and oleyl alcohol, or branched-chain alcohols, such as 2-ethylhexanol, can be used to make secondary ether fatty esters. The 5-ether fatty esters and the process for their formation have not been previously known and appear to be limited to structures where stabilized cations can be formed. The novel ethers were fully characterized by nuclear magnetic resonance and gas chromatography-mass spectrometry.     

烷基多苷的应用

简述了烷基多苷对眼睛和皮肤的刺激性、生物降解性、生态毒性、增黏性和抗菌性等。主要介绍了烷基多苷作为主表面活性剂或助表面活性剂用于化妆品、洗衣剂、餐具洗涤剂、食品、塑料、建材以及农药等产品中，起到协同增效作用以及降低其他表面活性剂的刺激性。同时指出了烷基多苷还可用于医药及三次采油等领域中。还可将烷基多苷进行衍生化，从而拓宽其应用领域。     

Neutron activation analysis and its application to the analysis of food products

High-flux thermal-neutron activation analysis (NAA) is an extremely sensitive means of quantitatively determining most of the elements of the periodic system. The usual limits of detection, for 75 of the elements, in the absence of appreciable interferences, range from picograms (for some elements) to as high as micrograms (for less sensitive elements). A typical element can be determined down to as low as a nanogram. This high sensitivity enables one to analyze food products, for example, for numerous trace-level elements that may be present: whether natural or added beneficial essential trace elements, or deleterious elements introduced from pesticide residues (such as Br, As and Hg), or from processing (such as Cr, Sn, Sb and Cu). Studies to be reported include the nondestructive determination of Hg in foodstuffs down to levels as low as 0.01 ppm, and of Br in foodstuffs down to about 0.1 ppm. With radiochemical separations, these detection limits can both be extended to 0.001 ppm, if needed. By combination with paper chromatographic or solvent extraction techniques, phosphorus- and halogen-containing pesticides can be sensitively determined. The NAA method can also be used to advantage at element levels much higher than trace levels, and in such cases the very high neutron flux of a nuclear reactor may not be necessary. For example, even with a small 14 Mev neutron generator, the nitrogen content of foodstuffs can be determined nondestructively, rapidly and accurately, down to levels of about 100 ppm. These determinations can also be made on-line, in food processing plants. Presented at the AOCS-AACC Joint Meeting, Washington, D.C., April, 1968.     

Catalytic conversion of biomass-derived carbohydrates to fuels and chemicals by formation and upgrading of mono-functional hydrocarbon intermediates

Aqueous solutions of sugars and polyols can be converted in a single catalytic process to produce a spontaneously separating organic phase consisting of hydrophobic mono-functional hydrocarbons. The process is shown to be stable for over 2 months time on stream at typical reaction conditions (e.g., 503 K and 18 bar total pressure). The composition and yield of this organic phase can be controlled by adjusting process variables, such as temperature, pressure and space velocity. This organic phase contains primarily mono-functional species such as ketones, alcohols, heterocycles, and organic acids. These oxygenated hydrocarbons can serve as an intermediate platform for the conversion of renewable biomass resources into chemicals and fuels. The organic phase can be separated into individual chemicals or can be upgraded to yield specific classes of chemicals. For example, heterocycles can be separated and used as solvents, additives or blending agents for transportation fuels, while aldol-condensation of the ketones and alcohols can produce long chains species for use as alkane fuels. Alternatively, this platform can be tuned to produce alcohols by reducing the ketone and acid groups. Dehydration of these alcohols produces olefins that have use in either the polymer industry, or as feeds for liquid fuels.     

Hydrotalcite-like anionic clays in catalytic organic reactions

Hydrotalcite-like anionic clays (HTs; or layered double hydroxides, LDHs) can be used as precursors to mixed oxides, but their catalytic potential reaches much further. This review demonstrates that HTs can be successfully applied in a broad spectrum of organic reactions, with advantages such as improved activity, selectivity, metal dispersion, less waste production, and an improved recuperation of immobilized catalysts. HTs can be used in the as-synthesized form or after different pretreatments. The HT as such is a solid base or, depending on the elemental composition of its octahedral layers, may have redox properties. Specific metals can be incorporated either as a cation in the octahedral layer or as an anion via exchange. The anion-exchange strategy is especially successful in the context of heterogenizing homogeneous catalysts. A particular advantage for base catalysis is that the number and strength of the basic sites can be tuned precisely to a specific reaction. HTs are excellent materials to design bifunctional redox-base catalysts or to control the acid-base properties around a heterogenized metal complex. Potential applications of HTs range from the production of large-scale basic chemicals to the synthesis of small-scale specialty chemicals.     

Hydrotalcite-like anionic clays in catalytic organic reactions

Hydrotalcite-like anionic clays (HTs; or layered double hydroxides, LDHs) can be used as precursors to mixed oxides, but their catalytic potential reaches much further. This review demonstrates that HTs can be successfully applied in a broad spectrum of organic reactions, with advantages such as improved activity, selectivity, metal dispersion, less waste production, and an improved recuperation of immobilized catalysts. HTs can be used in the as-synthesized form or after different pretreatments. The HT as such is a solid base or, depending on the elemental composition of its octahedral layers, may have redox properties. Specific metals can be incorporated either as a cation in the octahedral layer or as an anion via exchange. The anion-exchange strategy is especially successful in the context of heterogenizing homogeneous catalysts. A particular advantage for base catalysis is that the number and strength of the basic sites can be tuned precisely to a specific reaction. HTs are excellent materials to design bifunctional redox-base catalysts or to control the acid–base properties around a heterogenized metal complex. Potential applications of HTs range from the production of large-scale basic chemicals to the synthesis of small-scale specialty chemicals.     

General Requirements and Recommendations for Vapor Nucleation Rate Experiments

Agreement between experimentally measured vapor nucleation rates and current theoretical predictions exists for only a limited number of systems. These inconsistencies can result from differences in measurement methods and assumptions used to interpret the experimental results. Usually the causes of these disagreements are unclear. The current state of the art is such that experimental results using different methods can lead to very different interpretations of the same phenomenon. In this note, well-defined standard systems are suggested as a means to verify experimental system performance. The combination n-pentanol-helium is suggested as a standard reference system. Using this system, measurements produced by multiple research groups have been compiled, and from these experimental results, a nucleation rate equation was developed that can serve as a standard basis for method comparison. This equation provides a scale to relate nucleation rates over a range of nucleation temperatures and is a useful basis of comparison even if the proposed equation is not fully accurate. It is further suggested that the nucleation rate measurements be performed using small steps in nucleation temperature of around 2 or less to identify the features in the system such as phase changes in the critical embryos. In this note, a method that uses monotonicity and continuity conditions for the nucleation rate surface to detect such singularities is outlined. These monotonicity and continuity criteria can be formulated as a dimensionless quantity. The semiempirical construction of nucleation rate surfaces can indicate conditions where multiple nucleation rate surfaces may be detected. Experimental systems that include size distribution measurements have the potential to discern particles produced through multiple nucleation channels such that nucleation rates can be measured for each channel. Detection of nucleation rate surface singularities is important because these singularities indicate the existence of two-channel nucleation where one-channel nucleation theory cannot be applied.     

A Chiral Microporous Polymer Network as Asymmetric Heterogeneous Organocatalyst

Microporous polymer networks, composed of structure‐directing monomers (tectons), can exhibit high permanent surface area and porosity. By choice of suitable tectons various functionalities can be introduced into such networks. Here we introduce chiral BINOL derivatives as novel tectons to generate microporosity in polymer networks. The use of such monomers enables the formation of networks composed solely out of enantiomerically pure compounds. This porous network can be used as a heterogeneous organocatalyst in asymmetric reactions and gives higher enantioselectivty than the homogeneous reaction.     

Fish oil: production and use now and in the future

The global production of fish oil is around one million tonnes. This production is expected to be maintained. Rich in long‐chain omega‐3 fatty acids, especially EPA and DHA, it can supplement diets inadequate in these fatty acids such as those in many Western countries. Farmed fish, especially oily fish such as salmonids fed on fish oil provide an excellent source of these acids. Fish oil can be used directly in a purified form (nutraceuticals) in a wide range of foods. The daily recommended intake of EPA plus DHA of 0.25 to 0.50 g can then be met.     

Unique atmospheric plasma surface pretreatment approach for improving adhesion

Three‐dimensional parts and web‐processed products comprised of polyolefins, such as polypropylene, have low levels of polar functional groups on the surface and poor wettability and adhesion properties, thus making it difficult to apply other functional layers such as dyes, inks, adhesives, and coatings. To enhance surface polarity, surface treatments such as flame, corona, or plasma can be applied to improve wettability and adhesion. Plasma can be used specifically as a preparatory treatment for the photografting approach recommended in this paper in order to achieve high stability in treatment and permanent changes to the surface. J. VINYL ADDIT. TECHNOL., 13:87–90, 2007. © 2007 Society of Plastics Engineers.     

有机硅在聚氨酯中的应用

综述了有机硅在聚氨酯材料中的应用。聚硅氧烷可与聚氨酯形成共聚物，用于医学材料等；有机硅化合物还用作聚氨酯的改性剂，用于涂料，胶粘剂，密封剂，涂饰剂，织物整理剂等领域。对于提高聚氨酯性能，有机硅是一类十分有用的化合物。     

测算散料低速栓流气力输送压降和栓速的新方法

低速栓流气力输送技术已广泛应用于散料输送,然而对其输送对象的研究大多数针对有规则形状的散料（如塑料切片、小麦）,对于不规则形状的散料（如牛奶什锦早餐、玉米芽等）的研究却很少。提出了一种新的预测方法,它根据粒子的特性及从一个简单的垂直测试筒得到的数据,可以精确地预测低速栓流气力输送系统中的压降和栓速,即使是大型的气力输送系统。该方法适用于规则、不规则或不同性能（如不同形状、密度、粒径和粒度分布）的散料的低速栓流气力输送,预测的结果可满足设计和操作要求。     

Ionomer‐based polyurethanes: a comparative study of properties and applications

Polyurethanes cover a large range of materials exhibiting various physical and mechanical properties making them useful in different applications such as elastomers or biomaterials, for instance. The introduction of ionic groups in the polyurethane backbone opens the way to new applications where the ionic groups can act as physical crosslinkers that greatly modify the final mechanical and thermal properties of the materials. Furthermore, the hydrophilicity of the chains can be enhanced by the presence of the ionic species, and so the materials can be processed as conventional dispersions even in a polar solvent such as water. As a consequence the applications are numerous; the main commercial outlets are focused on coatings and textiles industries where they can be used as waterproof coatings or substitutes for leather. But these materials can also be used in high‐tech industries for shape memory materials, biomedical devices and biocompatible materials. This review summarizes the latest developments of this class of promising materials and provides the reader with the potentialities of these polymers in various areas.     

铝合金换向电流法氧化发色工艺的研究

采用周期换向电流法对铜较高的铝合金进行电解氧化发色。分别对温度与氧化电流密度等影响氧化膜生长速度与质量的工艺条件做了分析研究,取得了实用的工艺操作作规程。研究结果表明：应用周期换向电流法可以在硫酸溶液中对较难氧化着色的铝铜合金进行氧化发色,得到黄－黄绿－绿－黑绿－黑系列颜色的氧化膜。