Synthesis and evaluation of the glycosidase inhibitory activity of 5-hydroxy substituted isofagomine analogues

An efficient strategy for the synthesis of 5-hydroxy substituted isofagomine analogues and , having both -CH2OH/CH3 and -OH functionality at the C-5 position, and evaluation of their inhibitory potency is reported. The synthetic methodology involves the aldol-Cannizzaro reaction of easily available alpha-d-xylopentodialdose followed by hydrogenolysis to afford the triol . Selective amidation of the alpha- and beta-hydroxymethyl group at C-4, deprotection of the 1,2-acetonide group and hydrogenation gave the target molecules, which were found to be potent against beta-glycosidases with IC50 values in the micro molar range. Compound showed excellent potency against glycosidases and human salivary amylase.     

Different types of electrospun nanofibers and their effect on microfluidic‐based immunoassay

Protein capturing on polymeric substrate of microfluidic devices is a key factor for the fabrication of immunoassay with high sensitivity. In this work, simple and versatile technique of electrospinning was used to produce electrospun nanofibrous membranes (e.NFMs) with high surface area as a substrate for microfluidic‐based immunoassay to increase sensitivity. It was found that the simultaneous use of e.NFM and 1‐Ethylethyl‐3‐(3‐dimethylaminopropyl)‐carbodiimide/N‐Hydroxysuccinimide hydroxysuccinimide as coupling agent has synergic effect on antigen immobilization onto the microchannels. It was found that the oxygen plasma technique for the creation of oxygen containing functional group like carboxyl and hydroxyl causes extreme leakage of solution through the microchannels. Thus, due to capillary effect, it is impossible to use hydrophilic substrate to modify microchannels. In order to compensate this problem, it is propose to utilize other type of polymer for the fabrication of nanofiber to answer this important question that if it is possible to enhance the sensitivity of immunoassay just by changing the polymer type? For this purpose, four different polymers, namely, polycaprolactone, poly lactic‐co‐glycolic acid, poly L‐lactic acid, and polyethersolfone were used as the based material for e.NFM fabrication. Results showed that compared with plain poly (dimethylsiloxane) surface of microchannels, poly lactic‐co‐glycolic acidand poly L‐lactic acid, which inherently contain end‐group of carboxyl in their chemical structure, can improve the protein immobilization, which leads to immunoassay signal enhancement through 1‐ethyl‐3‐(3‐dimethylaminopropyl)‐carbodiimide/N‐hydroxysuccinimide coupling chemistry, significantly.     

Alcaloides steroidiques—LII Alcaloides du buxus balearica Willd.: Cycloprotobuxine-D, buxamine-E, buxaminol-E, N-isobutyryl-baleabuxidine-F, N-benzoyl-baleabuxidine-F, baleabuxoxazine-C, N-isobutyryl-baleabuxidienine-F, N-benzoyl-baleabuxidienine-F, N-isobutyryl-baleabuxaline-F

The following alkaloides have been extracted from the leaves of Buxus balearica Willd.: cyclomicrophylline-B, cycloprotobuxines A, C and D, baleabuxine (N-isobutyryl-baleabuxine-F), buxamine-E and buxaminol-E (already reported), N-isobutyryl- and N-benzoyl-baleabuxidine-F, baleabuxoxazine-C, N-isobutyryl- and N-benzoyl-baleabuxidienine-F, N-isobutyryl-baleabuxaline-F, the structures of which are proposed. The stereochemistry of baleabuxidines and baleabuxoxazines is established on the base of chemical correlations between these two groups and cyclomicrophyllines.     

Role of the ubiquitin proteasome system in Parkinson's disease

Parkinson's disease (PD) is the most common neurodegenerative movement disorder. Although a subject of intense research, the etiology of PD remains poorly understood. Recently, several lines of evidence have implicated an intimate link between aberrations in the ubiquitin proteasome system (UPS) and PD pathogenesis. Derangements of the UPS, which normally functions as a type of protein degradation machinery, lead to alterations in protein homeostasis that could conceivably promote the toxic accumulation of proteins detrimental to neuronal survival. Not surprisingly, various cellular and animal models of PD that are based on direct disruption of UPS function reproduce the most prominent features of PD. Although persuasive, new developments in the past few years have in fact raised serious questions about the link between the UPS and PD. Here I review current thoughts and controversies about their relationship and discuss whether strategies aimed at mitigating UPS dysfunction could represent rational ways to intervene in the disease. Publication history: Republished from Current BioData's Targeted Proteins database (TPdb; http://www.targetedproteinsdb.com).     

Determination of BTEX in Water Samples with an SPME Hollow Fiber Coated Copper Wire

A piece of copper wire coated with a polypropylene hollow fiber membrane was used as an SPME fiber and its efficiency for extraction of BTEX compounds from the headspace of water samples prior to GC analysis was evaluated. Under optimum extraction conditions, limits of detection for benzene, toluene, ethylbenzene, m-p-xylene, and o-xylene were found to be 0.11, 0.22, 0.26, 0.37, and 0.26 μg L^?1, respectively. Low detection limits, wide linear dynamic ranges, good reproducibility (RSD% <4), high fiber capacity and higher mechanical durability are some of the most important advantages of the new fiber.     

Preparation of La-Mo-V mixed-oxide systems and their application in the direct synthesis of acetic acid

In this study, mixed metal oxides developed with a perovskite-type structure that show great potential for use in catalysis. Perovskite oxide catalysts with the composition LaMoxV1-xOn （x = 0.1, 0.3, 0.5, 0.7, and 0.9） have been synthesized by the sol-gel method and then used in the ethane dry reforming reaction for the direct synthesis of acetic acid. The influence of the nature of the metallic source （metal, nitrate, acetylacetonate, and ammonium） on gel formation has been studied by Fourier-transform infrared spectroscopy （FT-IR） and thermogravimetric analysis （TGA-DTA）. After calcination, the obtained perovskites were characterized by X-ray diffraction （XRD） and energy-dispersive X-ray spectrometry （EDS） coupled with scanning electron microscopy （SEM）. The catalysts were then subjected to thermo-programmed reduction （TPR）. The surface area （BET） was found to increase from 2.6 m^2/g （x = 0.1） to 5.1 m2/g （x = 1.0） with increasing molybdenum content following calcinations at 750 °C, and pure LaMoxV1-xOn perovskite was obtained with good homogeneity. The catalysts have been characterized by XRD, SEM, EDS, and carbon analysis （CA）. The results indicate that through this synthesis it is possible to obtain highly crystalline, homogeneous and pure solids, with well-defined structures. The direct synthesis of acetic acid from ethane over the perovskite catalysts was studied at temperatures between 450 and 850 °C and elevated pressures between 1 and 8 bar. It was found that the yield of acetic acid and the selectivity of its formation could be increased by incorporating more molybdenum into the perovskite structure. The experimental studies have shown that the calcination temperature and the molybdenum content have a significant influence on the catalytic activity. Amongst the catalysts tested, LaMo0.7V0.3O4.2 exhibited the best activity and stability.     

Zeolite‐SiC in PVC Matrix as a New SPME Fiber for Gas Chromatographic Determination of BTEX in Water and Soil Samples

A new SPME fiber based on mixture of zeolite and silicon carbide in PVC matrix was made and its application for sampling of BTEX compounds from headspace of water and soil samples was studied. After optimization of conditions, the proposed fiber was used for determination of BTEX in real samples obtained from rivers and soils of gasoline reservoirs surroundings. The method has good linearity (0.991‐0.999) over wide concentration range. Detection limits of the method are in the range of 0.66–1.66 μg L^? and 0.01–0.12 μg kg^? for water and soil samples, respectively.     

Theory of integer-valued data envelopment analysis

Conventional data envelopment analysis (DEA) models assume real-valued inputs and outputs. In many occasions, some inputs and/or outputs can only take integer values. In some cases, rounding the DEA solution to the nearest whole number can lead to misleading efficiency assessments and performance targets. This paper develops the axiomatic foundation for DEA in the case of integer-valued data, introducing new axioms of “natural disposability” and “natural divisibility”. We derive a DEA production possibility set that satisfies the minimum extrapolation principle under our refined set of axioms. We also present a mixed integer linear programming formula for computing efficiency scores. An empirical application to Iranian university departments illustrates the approach.     

Liquid chromatographic determination of benomyl in water samples after dispersive liquid–liquid microextraction

A dispersive liquid–liquid microextraction (DLLME) method combined with solvolysis reaction for extraction of the carbamate fungicide benomyl as carbendazim from water samples is described. The method is based on the extraction of benomyl from acidified sample solution and its conversion into carbendazim via solvolysis reaction with DMF as organic solvent. The proposed DLLME method was followed by HPLC with fluorimetric detection for determination of benomyl. The proposed method has good linearity (0.998) with wide linear dynamic range (0.01–25 mg/L) and low detection limit (0.0033 mg/L), making it suitable for benomyl determination in water samples.