The Varietal Influence of Flavour Precursors from Grape Marc on Monoterpene and C13-Norisoprenoid Profiles in Wine as Determined by Membrane-Assisted Solvent Extraction (MASE) GC-MS

The winemaking by-product grape marc (syn. pomace) contains significant quantities of latent flavour in the form of flavour precursors which can be extracted and used to modulate the volatile composition of wine via chemical hydrolysis. Varietal differences in grapes are widely known with respect to their monoterpene content, and this work aimed to extend this knowledge into differences due to cultivar in volatiles derived from marc precursors following wine-like storage conditions. Marc extracts were produced from floral and non-floral grape lots on a laboratory-scale and from Muscat Gordo Blanco marc on a winery -scale, added to a base white wine for storage over five to six months, before being assessed using a newly developed membrane-assisted solvent extraction gas chromatography-mass spectrometry (GC-MS) method. The geraniol glucoside content of the marc extracts was higher than that of juices produced from each grape lot. In all wines with added marc extract from a floral variety, geraniol glucoside concentration increased by around 150–200%, with increases also observed for non-floral varieties. The relative volatile profile from extracts of the floral varieties was similar but had varied absolute concentrations. In summary, while varietally pure extracts would provide the greatest control over flavour outcomes when used in winemaking, aggregated marc parcels from floral cultivars may provide a mechanism to simplify the production logistics of latent flavour extracts for use in the wine sector.     

Crosslinked penicillin acylase aggregates for synthesis of β-lactam antibiotics in organic medium

Crosslinked enzyme aggregates (CLEAs) of a partially purified penicillin acylase from a recombinant Escherichia coli strain have been produced as a novel type of biocatalysts well endowed to perform in organic media. Different protein precipitants were studied and glutaraldehyde was used as the crosslinking agent. Precipitation curves were obtained for all precipitants to determine the concentrations at which all the protein precipitated out of the solution. The effect of the glutaraldehyde-to-protein ratio was studied with respect to process recovery and the specific activity and stability of the biocatalyst. Recovery of penicillin acylase activity was moderately high, about 50%; major losses of enzyme activity were produced at the precipitation step. Specific activities of all CLEAs were very high, which is one of the advantages of using nonsupported biocatalysts. Ammonium sulfate and tert-butyl alcohol were the best precipitants at a glutaraldehyde-protein mass ratio of 2 and were selected to perform the kinetically controlled synthesis of ampicillin in 60% (v/v) ethylene glycol medium. At comparable conversion yields, volumetric and specific antibiotic productivity were much higher for CLEAs than for carrier-bound penicillin acylases.     

NATURAL GAS OF NEW GENETIC TYPE——BIO-, THERMO-CATALYTIC TRANSITIONAL ZONE GAS

Bio-, thermo-catalytic transitional zone gas (BTCTZ gas), of which burial depth is shallow (1000-2500m), chemical composition (C,/ΣC1-5 = 0.7-0.9) and isotopic composition (δ13C1= -55 to-48‰) coincide with the evolution level of organic matter (R0=0.25-0.6%) in the corresponding strata, is a natural gas of new genetic type. The genesis of BTCTZ gas must have some relation to microcatalysis under lower temperature and condensation of aromatic hydrocarbons. In line with the new theory of natural gas formation, the existence of BTCTZ gas is objective. According to data from all over the world, BTCTZ gas may hold an important position in the table of reserves of natural gas.     

白酒中游离有机酸的定量测定

本文介绍了一种简单、准确测定白酒中游离有机酸的方法。酒样经中和、浓缩后,未经衍生直接注入毛细管色谱柱,经气相色谱-质谱鉴定并采用三种内标物定量,可准确测定白酒中C2～C18的二十种游离脂肪酸及三种苯羧酸,结果重现性良好。     

3-甲基环状乙撑磷酸二酯醇解的反应途径的理论研究

采用密度泛函理论和MP2方法研究了3-甲基环状乙撑磷酸二酯(MEP)与甲醇的反应途径:(Ⅰ)CH3O-+MEP;(Ⅱ)CH3OH+MEP;(Ⅲ)CH3O-+HMEP(MEP的质子化形式);(Ⅳ)CH3OH+HMEP.在B3LYP/6-31++G(d,p)水平上优化了四条反应途径的反应物、中间体、过渡态及产物的几何构型,并在同水平上进行了自然电荷分析,然后在MP2/6-311++G(3df,2p)水平上计算了各驻点的单点能.采用极化连续介质模型(PCM)研究了各途径在苯、甲醇和水溶液中的溶剂化效应.计算结果表明,溶剂效应使途径(Ⅰ)的自由能垒降低,而使途径(Ⅱ)和(Ⅳ)的决速步骤的自由能垒升高.在气相和苯溶剂中途径(Ⅳ)是反应的优势途径,在甲醇和水溶剂中途径(Ⅰ)则成为最优.研究结果进一步表明实验条件下途径(Ⅱ)与(Ⅳ)对总醇解反应的贡献相当.     

BEDT-TTF-based radical cation salt with the cyanurate anion: synthesis,structure, conductivity,and polarized reflection spectra

The new conducting radical cation salt, bis(ethylenedithio)tetrathiafulvalene cyanurate, was synthesized. This salt is an organic metal down to 4 K. The crystal structure, conductivity, and optical properties of the salt were studied. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 96–101, January, 2008.     

Rapid determination of trace polycyclic aromatic hydrocarbons in particulate matter using accelerated solvent extraction followed by ultra high performance liquid chromatography with fluorescence detection

A method has been developed for the trace analysis of polycyclic aromatic hydrocarbons, which are known as persistent organic pollutants and ubiquitous constituents of fine particulate matter that causes growing airborne pollution. The method, which was especially for samples of airborne particulate matter less than 2.5 μm in diameter, utilized accelerated solvent extraction and ultra high performance liquid chromatography with fluorescence detector. Four principal parameters of accelerated solvent extraction were optimized to obtain maximum extraction efficiency. Using the established synergetic programs of gradient elution and fluorescence wavelength switching, a rapid separation was achieved in 6.56 min with good linearity for 15 polycyclic aromatic hydrocarbons (coefficient of determination above 0.999). The limits of detection ranged from 0.833 to 10.0 pg/m³. The precision of the method expressed as inter‐day relative standard deviation ranged from 0.2 to 1%, which was calculated from nine repetitive measurements of 8.00 μg/L analytes. Average spiked recoveries ranged from 71.6 to 97.7%, with the exception of naphthalene. The rapid, sensitive, and accurate method can meet the pressing needs of health risk assessment and increasingly heavy daily tasks of air quality monitoring.     

Effect of the Terminal Acceptor Unit on the Performance of Non-Fullerene Indacenodithiophene Acceptors in Organic Solar Cells

Four acceptor–donor–acceptor (A–D–A)-type molecules bearing indacenodithiophene as donating central core and various end-capping acceptor units have been designed and synthesised as n-type materials suitable for organic solar cells (OSCs). The studied optical and electrochemical properties supported by theoretical calculations revealed that the nature and the strength of the terminal groups exert a decisive influence on the polymer bulk-heterojunction OSC performance.     

Energy,Exergy, Exergoeconomic and Emergy-Based Exergoeconomic (Emergoeconomic) Analyses of a Biomass Combustion Waste Heat Recovery Organic Rankine Cycle

In recent decades, there has been an increasing trend toward the technical development of efficient energy system assessment tools owing to the growing energy demand and subsequent greenhouse gas emissions. Accordingly, in this paper, a comprehensive emergy-based exergoeconomic (emergoeconomic) method has been developed to study the biomass combustion waste heat recovery organic Rankine cycle (BCWHR-ORC), taking into account thermodynamics, economics, and sustainability aspects. To this end, the system was formulated in Engineering Equation Solver (EES) software, and then the exergy, exergoeconomic, and emergoeconomic analyses were conducted accordingly. The exergy analysis results revealed that the evaporator unit with 55.05 kilowatts and the turbine with 89.57% had the highest exergy destruction rate and exergy efficiency, respectively. Based on the exergoeconomic analysis, the cost per exergy unit (c), and the cost rate (C˙) of the output power of the system were calculated to be 24.13 USD/GJ and 14.19 USD/h, respectively. Next, by applying the emergoeconomic approach, the monetary emergy content of the system components and the flows were calculated to evaluate the system’s sustainability. Accordingly, the turbine was found to have the highest monetary emergy rate of capital investment, equal to 5.43×1012 sej/h, and an output power monetary emergy of 4.77×104 sej/J. Finally, a sensitivity analysis was performed to investigate the system’s overall performance characteristics from an exergoeconomic perspective, regarding the changes in the transformation coefficients (specific monetary emergy).