Paper-based enzyme-free immunoassay for rapid detection and subtyping of influenza A H1N1 and H3N2 viruses

Development of rapid screening in the ambulatory environment is the most pressing needs for the control of spread of infectious disease. Despite there are many methods to detect the immunoassay results, quantitative measurement in rapid disease screening is still a great challenge for point-of-care applications. In this work, based on the internal structural protein, i.e., nucleoprotein (NP), and outer surface glycoproteins, i.e., H1 and H3, of the influenza viruses, specific and sensitive immunoassay on paper-based platform was evaluated and confirmed. Detection and subtyping of influenza A H1N1 and H3N2 viruses found in people were demonstrated by colorimetric paper-based sandwich immunoassay. Concentration-dependent response to influenza viruses was shown and the detection limits could achieve 2.7 × 10³ pfu/assay for H1 detection and 2.7 × 10⁴ pfu/assay for H3 detection, which are within the clinical relevant level. Moreover, detection of influenza virus from infected cell lysate and clinical samples was demonstrated to further confirm the reliability of the paper-based immunoassay. The use of paper for the development of diagnostic devices has the advantages of lightweight, ease-of-use, and low cost and paper-based immunoassay is appropriate to apply for rapid screening in point-of-care applications.     

Fermentation kinetics of ethanol production from glucose and xylose by recombinant Saccharomyces 1400(pLNH33)

Fermentation kinetics of ethanol production from glucose, xylose, and their mixtures using a recombinant Saccharomyces 1400 (pLNH33) are reported. Single-substrate kinetics indicate that the specific growth rate of the yeast and the specific ethanol productivity on glucose as the substrate was greater than on xylose as a substrate. Ethanol yields from glucose and xylose fermentation were typically 95 and 80% of the theoretical yield, respectively. The effect of ethanol inhibition is more pronounced for xylose fermentation than for glucose fermentation. Studies on glucose-xylose mixtures indicate that the recombinant yeast co-ferments glucose and xylose. Fermentation of a 52.8 g/L glucose and 56.3 g/L xylose mixture gave an ethanol concentration of 47.9 g/L after 36 h. Based on a theoretical yield of 0.51 g ethanol/g sugars, the ethanol yield from this experiment (for data up to 24 h) was calculated to be 0.46 g ethanol/g sugar or 90% of the theoretical yield. The specific growth rate of the yeast on glucose-xylose mixtures was found to lie between the specific growth rate on glucose and the specific growth rate on xylose. Kinetic studies were used to develop a fermentation model incorporating the effects of substrate inhibition, product inhibition, and inoculum size. Good agreements were obtained between model predictions and experimental data from batch fermentation of glucose, xylose, and their mixtures.     

Effects of surfactant micelles on viscosity and conductivity of poly(ethylene glycol) solutions

The neutral polymer-micelle interaction is investigated for various surfactants by viscometry and electrical conductometry. In order to exclude the well-known necklace scenario, we consider aqueous solutions of low molecular weight poly(ethylene glycol) (2-20)x10(3), whose radial size is comparable to or smaller than micelles. The single-tail surfactants consist of anionic, cationic, and nonionic head groups. It is found that the viscosity of the polymer solution may be increased several times by micelles if weak attraction between a polymer segment and a surfactant exists, epsilon相似文献   

Formal Syntheses of (±)‐Methylenomycins A and B

The syntheses of methyl ester of (±)‐desepoxy‐4,5‐didehydromethylenomycin A ( 4 ) and 2,3‐dimethyl‐5‐methoxycarbonyl‐2‐cyclopentenone ( 5 ) were accomplished from a common starting material, 2,3‐dimethyl‐4‐methoxyphenol (8), in only four and two steps in 35% and 53% overall yields, respectively. Photochemical rearrangements of masked p‐benzoquinones in methanol are the key steps.     

Coproduction of ethanol and glycerol

Ethanol and glycerol are both metabolic products of yeasts. There are occasions when coproduction of both is considered desirable in industrial operations. In this article, we describe the potential of integrating the two processes. A LORRE Y8 yeast culture isolated from molasses is capable of efficient glycerol production from glucose, and a yeast Culture 1400 is an excellent producer of ethanol. By controlling the process conditions, the ratio of ethanol and glycerol production can be varied.     

Synthesis of 3-(5-Aryl-1,3,4-oxadiazol-2-yl)chromones

A general procedure was proposed for the synthesis of 3-(5-aryl-1,3,4-oxadiazol-2-yl)chromones by reaction of 3-formylchromone with aroylhydrazines, transformation of the corresponding acylhydrazones into 1,3-dipoles by the action of bromine in the presence of sodium acetate, and intramolecular ring closure.     

Lutein in selected Canadian crops and agri-food processing by-products and purification by high-speed counter-current chromatography

This study mainly focused on lutein content in several selected crops grown in southern Ontario, Canada. Marigold flower, a good rotation crop for the control of nematodes in tobacco fields was found to contain 0.77% lutein (after saponification, on dry basis). A high-speed counter-current chromatography (HSCCC) method using a two-phase solvent system consisting of hexane-ethanol-water (6:4.5:1.5, v/v/v) was developed for the purification of lutein from the saponification mixture of marigold flower extract. The purity of lutein prepared using this HSCCC method was 97%. Free lutein was found to be the predominant form in three squash varieties, and it was mostly found in the peel rather than the commonly consumed flesh. Sweet Mamma, Buttercup and Pepper squash varieties contained 25.4, 18.4 and 30.1mg/100g fresh weigh (FW) of lutein in the peels, respectively. These concentrations were significantly higher than that in spinach and kale (3.7 and 12.3 mg/100 g FW). beta-Carotene was found most in the peel of Sweet Mamma squash at 13.6 mg/100g FW, whereas it was below 2mg/100g FW in all other samples. Cooking increased extractable free lutein by 22-65% in squash peels. Lutein in Yukon Gold potato was at ca. 0.4 mg/100 g FW. Certain Yukon Gold was also found to contain violaxanthin (0.35 mg/100 g FW). Structures of lutein, beta-carotene and violaxanthin were identified by LC-atmospheric pressure chemical ionization MS in positive ion mode, and by comparing the retention time and UV-vis spectral data with standards. Results from this study suggest the selected crops and agri-food industrial processing by-products of these can be a good source of free lutein.     

Organic dyes containing fused acenes as building blocks: Optical,electrochemical and photovoltaic properties

Fused-acenes are important building blocks for D-p-A sensitizers. The small change in substituted heteroatoms influence the behavior of the sensitizers dramatically.     

Optimization of L-Lactic acid production from glucose by Rhizopus oryzae ATCC 52311

The effect of nutrients on L(+)-lactic acid production from glucose was investigated using Rhizopus oryzae ATCC 523 11. From the shake-flask experiments, the optimal medium composition was defined for improved lactic-acid production. In order to enhance lactic-acid production rate and product yield, controlled aeration in a bubble column was conducted under optimal conditions. Results showed a maximum lactic-acid production rate of 2.58 g/L/h was obtained with an initial glucose concentration of 94 g/L. Finallactic-acid concentration of 83 g/L was achieved after 32 h of fermentation with a weight of 0.88 glactic acid/g glucose consumed.     

Composite spring model in stretched polymer knots

The deformation of a knotted polymer under a stretching force is studied by modeling the deformed knot as a composite spring system. Our results predict that the elastic modulus of a knotted polymer is larger when compared to an equal‐length linear chain. More complex knots are in general stiffer. The increase in stiffness of knots relative to the linear chain is also derived. Monte Carlo simulations are also performed to investigate the streching of polymer knots. Chain lengths up to N = 82 and prime knots 0₁ , 3₁ , 4₁ , 5₁ , 6₁ and 8₁ are considered. Segregation of the crossings into a small tight region of the knot structure at strong forces is observed. The increase in stiffness predicted by the composite spring model agree well with the simulation data. Our simulation data show that the scaling laws proposed by de Gennes and Pincus for a single linear chain under traction force still hold for the knotted type polymers.