Surface plasmon resonance biosensor for rapid label-free detection of microribonucleic acid at subfemtomole level

Microribonucleic acids (miRNAs) have been linked with various regulatory functions and disorders, such as cancers and heart diseases. They, therefore, present an important target for detection technologies for future medical diagnostics. We report here a novel method for rapid and sensitive miRNA detection and quantitation using surface plasmon resonance (SPR) sensor technology and a DNA*RNA antibody-based assay. The approach takes advantage of a novel high-performance portable SPR sensor instrument for spectroscopy of surface plasmons based on a special diffraction grating called a surface plasmon coupler and disperser (SPRCD). The surface of the grating is functionalized with thiolated DNA oligonucleotides which specifically capture miRNA from a liquid sample without amplification. Subsequently, an antibody that recognizes DNA*RNA hybrids is introduced to bind to the DNA*RNA complex and enhance sensor response to the captured miRNA. This approach allows detection of miRNA in less than 30 min at concentrations down to 2 pM with an absolute amount at high attomoles. The methodology is evaluated for analysis of miRNA from mouse liver tissues and is found to yield results which agree well with those provided by the quantitative polymerase chain reaction (qPCR).     

基于IFS确定性迭代算法的麦粒分形组织设计法

针对L系统在绘制织物分形组织图方面存在的局限,运用IFS的确定性迭代算法生成规则,结合计算机图形方法,提出了一种分形组织图的纹织效果设计方法。该设计方法以复杂变化组织中的麦粒组织为基础组织,基于IFS生成具有自相似结构的分形组织图,然后选择不同形式的组织为填充组织,从而获得具有特殊纹理效果的分形织物组织图。结合纺织CAD技术,借助电子提花机进行了相应的组织织造实验,对设计形成风格新奇的织物组织的新方法进行了初步的探讨。     

Preparation of spherical macroporous silica in an aerosol phase

Macroporous silica (MS) and macro/mesoporous silica (MMS) were prepared by spray drying a polystyrene (PS) latex sol containing a silica source, followed by calcination. As a silica source, 3-aminopropyl triethoxysilane (APS) was used for MS while either silica sol (SS) or tetraethoxyothosilicate using P123 templating (P123-TEOS) was used for MMS. Spray drying and calcination could also take place in a once-through aerosol reactor. The transformation of the silicon alkoxides to silica and decomposition of PS occurred at similar temperatures. Therefore, for APS-originated MS, the metal additives such as silver and nickel were required to accelerate the former. In addition, the nickel was well dispersed in the silica matrix during calcination even at 800 °C, in turn to thermally stabilize the porous structures. The wall-preforming additives were unnecessary for PS/SS and PS/P123-TEOS, since the SS drying and P123 templating, respectively, took place at lower temperature than PS decomposition. The porosities of all the porous silica prepared ranged from 0.54 to 0.57, which were close to the volume fraction of PS in the PS-alkoxides mixture solidified right after spray drying.     

Automated Sequential Injection Method for Determination of Caffeine in Coffee Drinks

An automated sequential injection analysis spectrophotometric assay for the determination of purine alkaloids in coffee drinks was developed. The sample was treated with a carrez reagent for matrix suppression followed by filtration; subsequently, alkaloids were separated from organic acids using a short C18 monolithic column (10 × 4.6 mm). The flow rate of the separation step was 10 μL s^?1 with 10% v/v of methanol as the mobile phase. The sum of alkaloids evaluated as caffeine was detected at 274 nm. The influence of the main parameters affecting the quantification of purine alkaloids was optimized. One sample analysis lasted 15 min when aspirated in triplicate. The linear range was 1–15 mg L^?1, and the determination coefficient (r ²) was 0.9969. The limit of detection and limit of quantitation were 0.128 and 0.425 mg L^?1, respectively. The repeatability evaluated as the relative standard deviation (RSD) was 3.58% (n = 12, 10 mg L^?1). Under optimal conditions, the method was successfully applied to determine purine alkaloids in different real samples including soluble coffee, coffee from an espresso machine, and brewed coffee drinks.     

Osmoresistant yeast Zygosaccharomyces rouxii: the two most studied wild-type strains (ATCC 2623 and ATCC 42981) differ in osmotolerance and glycerol metabolism

The yeast Zygosaccharomyces rouxii is known for its high tolerance to osmotic stress, which is thought to be caused by sets of specific genes. Relatively few Z. rouxii genes have been identified so far, all of them having homologues in Saccharomyces cerevisiae; none of them was Z. rouxii-specific. Most of the known Z. rouxii genes were isolated from two wild-type strains, ATCC 2623 and ATCC 42981. In this study, we compared these two strains with regard to some of their morphological, physiological and genomic properties. Important differences were found in their salt tolerance and assimilation of glycerol and karyotype; slight differences were also present in their cell morphology. The ATCC 42981 strain showed a higher resistance to salts, higher glycerol production and, unlike ATCC 2623, was able to assimilate glycerol. Under conditions of osmotic stress, the glycerol production in both Z. rouxii strains was much lower than in a S. cerevisiae S288c culture, which suggested the presence of a system that efficiently retains glycerol inside Z. rouxii cells. The karyotype analysis revealed that ATCC 42981 cells contain more chromosomes and have a bigger genome size than those of ATCC 2623.     

Energy Losses Estimation During Pulsed-Laser Seam Welding

The finite-element tool SYSWELD (ESI Group, Paris, France) was adapted to simulate pulsed-laser seam welding. Besides temperature field distribution, one of the possible outputs of the welding simulation is the amount of absorbed power necessary to melt the required material volume including energy losses. Comparing absorbed or melting energy with applied laser energy, welding efficiencies can be calculated. This article presents achieved results of welding efficiency estimation based on the assimilation both experimental and simulation output data of the pulsed Nd:YAG laser bead on plate welding of 0.6-mm-thick AISI 304 stainless steel sheets using different beam powers.     

Encapsulation of aliphatic amines into nanoparticles for self-healing corrosion protection of steel sheets

A noble approach based on the encapsulation of corrosion inhibitors has been presented, which are capable of improving the active corrosion protection without negatively influencing the barrier properties of the coating layers. Polymeric nanocapsules loaded with six types of amine corrosion inhibitors were synthesized by multi-stage emulsion polymerization. Depending on the basicity and water solubility of amines, different amounts of releasable corrosion inhibitors were encapsulated into the polymer capsules. Encapsulated organic amines were generally well released under alkaline conditions, and linear amines were more easily released from inside capsules than branched ones. The nanocapsules were incorporated into the coating resin and were coated on cold-rolled steel sheets to investigate corrosion protection efficiencies. The corrosion inhibitive efficiencies of the nanocapsule-containing coating layers were evaluated by electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET). In this study, it was revealed that the intrinsic properties of the amines as well as their encapsulation/release behaviors determined the barrier property and self-healing protection capability of the coating layer.