Alcohol Acetate Research Articles

약물 방출 스텐트의 약물 방출 및 기계적 특성에 Ethylene Vinyl Alcohol와 Cellulose Acetate Butyrate가 미치는 영향

약물 방출 스텐트의 약물 방출 및 기계적 특성에 Ethylene Vinyl Alcohol와 Cellulose Acetate Butyrate가 미치는 영향

The influence of pre-fermentative maceration and ageing factors on ester profile and marker determination of Pedro Ximenez sparkling wines.

The influence of pre-fermentative maceration and ageing factors on the ester profiles of Pedro Ximenez sparkling wines was evaluated. The pre-fermentative maceration consisted of the skin-maceration of musts at 10°C for 6h. The sparkling wines were produced following the Champenoise method. Samples were monitored at 3, 6 and 9months of ageing on lees. Sparkling wines with pre-fermentative maceration displayed higher contents of ethyl esters of branched acids and cinnamates. Meanwhile, those without maceration showed higher levels of ethyl esters of fatty acids and higher alcohol acetates. The study of statistical interactions elucidated different hydrolytic kinetics and developments in higher alcohol acetates and ethyl esters of branched acids during ageing. The application of a dual criterion based on univariate (ANOVA) and multivariate analyses (OPLS-DA) allowed us to identify new potential volatile markers related to pre-fermentative maceration and ageing time, reported for the first time in sparkling wines.

Theta Activity in the Regio Inferior of the Temporal Hippocampus by Odor Stimulation in Anesthetized Pigs

We examined theta activity in the temporal hippocampus of ure-thane-chloralose-anesthetized pigs by stimulation with two chemical odors, beta-phenyl ethyl alcohol (PEA; rose-like odor) and n-amyl acetate (banana-like odor). Neural activity was recorded in the neural cell layer nearby fimbria of the temporal hippocampus in three of six animals. Odor stimulation with PEA at a low concentration (10-4 w/w; 100 ppm) significantly increased power of the low-frequency theta band (type-2; 4 - 6 Hz) for the middle 10 s (w (3, 6, 2.5%) >2.56). The PEA odor at a higher concentration (10-3 w/w; 1000 ppm), however, showed a tendency for gradual increase in the low-frequency theta but the response was insignificant compared with the control. On the other hand, odor stimulation with n-amyl acetate (10-4 w/w; 100 ppm) caused no apparent increase or a tendency for decrease in power of the low-frequency theta. Thus, the type-2 theta response in the temporal hippocampus to the PEA odor contrasted strikingly with that to the n-amylacetate in the ure-thane-chloralose-anesthetized pigs. The response of the type-2 theta rhythm in the temporal hippocampus may underlie the difference in emotional sensation and cognition of PEA from n-amyl acetate in the pig.

A Microtiter Plate-Based Assay to Screen for Active and Stereoselective Hydrolytic Enzymes in Enzyme Libraries.

A procedure for the high-throughput screening (HTS) of esterases is described. This includes a pretest for discrimination of active and inactive clones using an agar plate overlay assay, the enzyme expression in microtiter plates and the measurement of activity and enantioselectivity (E) of the esterase variants using acetates of secondary alcohols as model substrates. Acetic acid released is converted in an enzyme cascade leading to the stoichiometric formation of NADH, which is quantified in a spectrophotometer. The method allows screening of several thousand mutants per day and has already been successfully applied to identify an esterase mutant with an E > 100 towards an important building block for organic synthesis. This protocol can also be used for lipases and possibly other hydrolases that are expressed in soluble form in conventional E. coli strains.

Improved enantioselectivity of thermostable esterase ST0071 from archaeon Sulfolobus tokodaii by site-saturation mutagenesis

An archaeon GGG(A)X-type esterase (ST0071) can catalyze the hydrolysis of various acetates of secondary alcohols, but shows low enantioselectivity. Using structure-guided site-saturation mutagenesis, we successfully identified a G274W variant that has excellent selectivity compared with that of wild-type ST0071.

ChemInform Abstract: Graphite Oxide‐Catalyzed Acetylation of Alcohols and Phenols.

Abstract Graphite oxide (GO) was used as a catalyst for the reactions of alcohols and phenols with acetic anhydride. The acetates of primary and secondary alcohols were prepared in good to excellent yields in short reaction time under mild conditions. Electron deficient phenols could be converted to the corresponding acetates steadily. As an efficient catalyst, GO is easily available, cheap, moderately toxic and weakly acidic.

Anti-Inflammatory Activity of <i>Chrozophora rottleri</i> Extracts on Carrageenan-Induced Rat Paw Edema

The present study was intended to evaluate Anti-inflammatory activity ofC. rottleriextracts (Hydroalcoholic, Methanol, Ethyl acetate and Hexane). The Anti-inflammatory activity ofC.rottleriextracts at doses of 125mg/kg, 250mg/kg and 500mg/kg using carrageenan induced rat paw edema model compared with standard drug (Indomethacin). The selected plant extracts significantly inhibited paw edema along with the standard drug Indomethacin. Of all extracts, methanol extract produced significant effect on reduction of increased paw thickness, hydro alcoholic and ethyl acetate extracts produced moderate percentage inhibition and hexane extract produced low level of percentage inhibition in reducing paw edema on carrageenan induced rats. In all extracts, methanol extract at a dose of 500mg/kg showed more percentage inhibition i.e . 53.47±2.19. From the results obtained during the study it is concluded thatC. rottlerihaving the bioactive molecule responsible for Anti-inflammatory activity by individually or by combination of different bio-active compounds present in it. Further is necessary for isolation and characterization of bioactive molecules which are responsible for the selected plant biological activities.

MACRO DEFECT FREE CEMENTS: A REVIEW

The usage of polymers in different sectors has been increasing in recent decades, and even our current age may have been defined as polymer age. When concrete is considered polymers are also widely used to modify the properties of both mortar and concrete and the usage of polymers in concrete dates back to 1920’s. On the other hand, Macro-defect free (MDF) cements are one particular type of cement-polymer composites and developed and patented by scientists at Imperial College at the beginnings of 1980’s. MDF cements are produced by mixing cement (commonly calcium aluminate cement) with small amounts of polymer (usually polyvinyl alcohol acetate) and water. High shear, relatively low pressure (about 5 MPa) and moderate temperature (about 80-100 °C) are applied during the production of this material. MDF cements, although consist of more than 80% by weight of cement, show 20-30 times higher flexural strength comparing to ordinary Portland cements. However, MDF cements show a considerable reduction in strength when they are exposed to water even for a short time. Many studies have been conducted to solve the water sensitivity of MDF cements for over 30 years. In this study, production, basic properties and the current state of the art of MDF cements are explained, and the future research works are suggested.

Berry Shriveling Significantly Alters Shiraz (Vitis vinifera L.) Grape and Wine Chemical Composition.

Berry shriveling is an often reported occurrence in the Shiraz (Vitis vinifera L.) cultivar. This study investigated the effect of berry shriveling occurring in a high yielding (18.6 ± 1.6 kg/vine) Shiraz vineyard in relation to a temporal investigation of grape and wine composition using three harvest dates. Berry shriveling resulted in delayed total soluble solids and amino acid accumulation into the berry, however differences between treatments diminished or became smaller by the third harvest date. Similarly, ethyl esters of fatty acids and higher alcohol acetates were lower in wines from shriveled berries from the first two harvests; anthocyanins were reduced in wines from shriveled berries at all harvest dates, whereas terpenes were unaltered. Wines made from shriveled berries had higher γ-nonalactone and β-damascenone concentrations. This study provides novel information on the chemical alterations of grapes and wines made from grapes affected by shriveling.

Graphite oxide-catalyzed acetylation of alcohols and phenols

Graphite oxide (GO) was used as a catalyst for the reactions of alcohols and phenols with acetic anhydride. The acetates of primary and secondary alcohols were prepared in good to excellent yields in short reaction time under mild conditions. Electron deficient phenols could be converted to the corresponding acetates steadily. As an efficient catalyst, GO is easily available, cheap, moderately toxic and weakly acidic.

Comparison Scent Compound Emitted from Flowers of Damask Rose and Persian Musk Rose

Rose emits a great group of scent that is functional in their communication with their instantaneous environment. In this study, the chemical compositions of floral scent from Damask and Musk roses flowers were isolated at full bloom stage by using headspace extraction. The main floral headspace components in Damask rose were Phenylethyl alcohol (2-phenylethanol), β-citronellol, α-Pinene and Geranyl acetate however the main components in Musk rose were Phenylethyl alcohol, 1-Nonadecene, Heneicosane and n-Nonadecane. In the both of species, the relative percentage of Phenyl ethyl alcohol was main scent compound. β-citronellol, α-Pinene and Geranyl acetate were highest and a major component in the Damask rose however these components (except α-Pinene) were not detected in Musk rose. The results of this study indicated that a number of factors, including particular rose species and the genetic triggers for releasing fragrance, determine the amount of fragrance.

A Cobalt (II) Complex [Co(VIM)4](NCS)2 Based on 1-vinylimidazole (VIM) and SCN–

A cobalt complex of [Co(VIM)4](NCS)2 (VIM = 1-vinylimidazole) was synthesized by 1-vinylimidazolium with CoCl2 and KSCN in acetone. The structure was determined by X-ray crystallography, infrared spectrum, and elemental analysis. The coordination environment of the Co atom was basically octahedron, comprising four nitrogen atoms from 1-vinylimidazole ring and two nitrogen atoms from NCS– anion. The 3D supramolecular structure is constructed with the hydrogen bond intermolecular interactions. The melting temperature of complex [Co(VIM)4] (NCS)2 is 153.6°C, the solidification temperature is 119.9°C. The title complex is easily soluble in acetone, slightly soluble in methanol, alcohol, chloroform and ethyl acetate, insoluble in petroleum ether, water, and benzene.

Inactive dry yeast application on grapes modify Sauvignon Blanc wine aroma

This study investigated the potential to improve wine aroma by applying two inactive dry yeast products (IDYs) at the onset of ripening on Sauvignon Blanc grapes. Both products led to increased reduced glutathione concentrations in the grape juice and corresponding wines, as well as differences in individual higher alcohol acetates (HAAs) and ethyl esters of straight chain fatty acids (EEFAs) at the end of fermentation. After two months of storage, a significantly slower decrease of EEFAs and to a lesser extent of HAAs was found for wines made from grapes with IDY applications. These wines also resulted in significantly slower synthesis of ethyl esters of branched acids, whereas varietal thiols were altered in a product-specific manner. The modifications in the wine chemical composition were also sensorially corroborated. This study showed that vineyard additions of IDY products directly on the grapes at the onset of ripening have a subsequent benefit to the production and preservation of aroma in wines.

A re-examination of corn (Zea mays L.) ear volatiles

Helicoverpa zea (Boddie) is a major insect pest of corn and other agricultural crops. An improved understanding of semiochemcials that control adult behavior is needed to develop alternative control measures. In this study, overnight SPME collection of volatiles from corn ears enclosed in Teflon bags in the field at two stages of development were made. C8–C10 aldehydes, a C8-alcohol, C6–C9 alcohol acetates, and numerous monoterpenes, sesquiterpenes, sequiterpene alcohols, and geosmin were identified after thermal desorption and GC/MS. Structural assignments of the alcohol acetates, Z-3-hexenyl acetate, 2-heptyl acetate, 2-nonyl acetate, and 4-nonyl acetate, the monoterpenes, α- and β-ocimene, and geosmin were made by analysis of standards that were purchased or prepared in the laboratory. All other assignments were based on published Kovat’s retention time indices (KI) and mass spectra. Pair-wise comparison of the relative amounts of each component between two groups of corn ears defined by silk weight did not identify significant differences, thus it is unknown whether or not silk weight impacted volatile emission composition and rate. To our knowledge three compounds detected in SPME collections, 2-heptyl acetate, 2-nonyl acetate, and 4-nonyl acetate have not been previously reported in corn ear or silk volatiles. Their impact on the flight response of gravid earworm females was evaluated in a flight chamber. No significant response to the individual compounds or a blend of all three was observed. Thus, their impact on moth behavior remains uncertain.

Answer to the Letter to the Editor by Dr. Sanjay Pralhad Shirsat concerning the article “Separation of isobutyl alcohol and isobutyl acetate by extractive distillation and pressure-swing distillation: Simulation and optimization”

Answer to the Letter to the Editor by Dr. Sanjay Pralhad Shirsat concerning the article “Separation of isobutyl alcohol and isobutyl acetate by extractive distillation and pressure-swing distillation: Simulation and optimization”

Metabolic engineering of Escherichia coli for production of biodiesel from fatty alcohols and acetyl-CoA.

Microbial production of biodiesel from renewable feedstock has attracted intensive attention. Biodiesel is known to be produced from short-chain alcohols and fatty acyl-CoAs through the expression of wax ester synthase/fatty acyl-CoA: diacylglycerol acyltransferase that catalyzes the esterification of short-chain alcohols and fatty acyl-CoAs. Here, we engineered Escherichia coli to produce various fatty alcohol acetate esters, which depend on the expression of Saccharomyces cerevisiae alcohol acetyltransferase ATF1 that catalyzes the esterification of fatty alcohols and acetyl-CoA. The fatty acid biosynthetic pathways generate fatty acyl-ACPs, fatty acyl-CoAs, or fatty acids, which can be converted to fatty alcohols by fatty acyl-CoA reductase, fatty acyl-ACP reductase, or carboxylic acid reductase, respectively. This study showed the biosynthesis of biodiesel from three fatty acid biosynthetic pathway intermediates.

MULTIPLE INTERACTIONS MIXED MATRIX MEMBRANE CHROMATOGRAPHY USING ANION AND CATION EXCHANGER RESIN FOR WHEY PROTEIN FRACTIONATION

Membrane chromatography can overcome the limitation of packed bed chromatography in terms of high processing speed, low pressure drop and acceptable protein binding capacity. In the current study, multiple interactions mixed matrix membrane (MMM) chromatography was prepared for batch fractionation of whey protein. Lewatit CNP105 cation exchanger resin and Lewatit MP500 anion exchanger resin were mixed into two different membrane polymer solutions of ethylene vinyl alcohol (EVAL) and cellulose acetate (CA). The membranes were test to bind lactoferrin (LF)-spiked whey. The binding capacity for acidic whey proteins to the MMM follows the order of β-lactoglobulin (β-Lac) > BSA > α-lactalbumin. The binding capacity of EVAL MMM is higher than CA based MMM, more prominently for β-Lac. The average binding capacity of β-Lac in the EVAL and CA MMM are 50.827 mg β-Lac/ g MMM and 19.174 mg β-Lac /g MMM, respectively. High purity of β-Lac and LF were recovered from the MMM after the elution as shown by the SDS PAGE gel.

Substrate specificity of an esterase from the archaeon Sulfolobus tokodaii bearing a GGG(A)X motif

A GGG(A)X-type esterase (Est0071) from an archaeon catalyzes asymmetric hydrolysis of prochiral bulky malonic diesters in good enantioselectivity. The selectivity of Est0071 was for the opposite enantiomer to that previously shown for pig liver esterase, and the resulting enantiomeric excess of the products was higher. Est0071 could also catalyze the hydrolysis of various acetates of secondary alcohols, and showed moderate enantioselectivity in these reactions.

Clonal differences and impact of defoliation on Sauvignon blanc (Vitis vinifera L.) wines: a chemical and sensory investigation.

The aim of this study, performed on Sauvignon blanc clones SB11 and SB316, grafted on the same rootstock 101-14 Mgt (Vitis riparia × V. ruperstris) and grown at two adjacent vineyards, was two-fold: (1) to study wine chemical and sensory composition of both clones within an unaltered canopy; and (2) to determine the effect of defoliation (e.g. bunch microclimate) on wine chemical and sensory composition. Orthogonal projection to latent structures discriminate analysis (OPLS-DA) was applied to the concentration profiles of volatile compounds derived from gas chromatography-mass spectrometry data. The loadings directions inferred that 3-isobutyl-2-methoxypyrazine (IBMP) discriminated control treatments (shaded fruit zone) of both clones from defoliation treatments (exposed fruit zone), whereas 3-sulfanyl-hexan-1-ol (3SH), 3-sulfanylhexyl acetate (3SHA), hexanol, hexyl hexanoate and some other esters discriminated defoliated treatments from the controls. The OPLS-DA indicated the importance of IBMP, higher alcohol acetates and phenylethyl esters, for discrimination of clone SB11 from clone SB316 irrespective of the treatment. Defoliation in the fruit zone significantly decreased perceived greenness in clone SB11 and elevated fruitier aromas, whereas in clone SB316 the effect of defoliation on wine sensory perception was less noticeable regardless the decrease in IBMP concentrations. These findings highlight the importance of clone selection and bunch microclimate to diversify produced wine styles.

Kinetic resolution of esters from secondary and tertiary benzylic propargylic alcohols by an improved esterase-variant from Bacillus sp. BP-7

We described in a recent work the rational improvement of an esterase from Bacillus sp. BP7 aimed at investigating the efficiency of several esterase variants for enantiomeric resolution of acetate esters of tertiary alcohols. Variant EstBP7-AGA, bearing two aminoacidic changes in the oxyanion hole, showed an excellent E>100 enantioselectivity value towards a complex tertiary alcohol acetate (2-(4-pyridyl)-3-butyn-2-yl acetate) at low reaction temperature (4°C). We here go further in the investigation of such esterase variant by analyzing the kinetic resolution of benzylic propargylic esters to prove that this enzyme is a powerful tool to obtain enantiomerically pure tertiary as well as secondary alcohols, provided that the structural integrity of the parent benzylic propargylic ester is maintained. Understanding the mode of action and interaction of such esterase variant with the assayed substrates will allow production of interesting pharmaceutical building blocks.