Technical note: Characterization of key volatile odorants in rabbit meat using gas chromatography mass spectrometry with simultaneous distillation extraction

[EN] This study explored the key volatile compounds in both male and female rabbit meat. Simultaneous distillation extraction with dichloromethane was adopted to extract the volatile compounds in Hyla rabbit meat. A total of 35 volatile compounds were identified by gas chromatography–mass spectrometry and quantified with 2, 4, 6-thimethylpyridine as internal standard. Seventeen volatile aldehydes, 4 alcohols, 2 ketones, 2 acids, 1 heterocyclic compound, 2 alkanes and 7 esters were detected. Hexanal, heptanal, octanal, nonanal, (E, E)-2, 4-decadienal, 1-octen-3-ol and (Z)-2-decenal were the key odorant compounds, with high relative odour activity value. Furthermore, the concentration of volatile compounds in male rabbit meat was higher than that in female rabbit meat.This work was supported by the National Natural Science Foundation of China (31671787), the Chinese Rabbit Industry System of Education Ministry (100030-40305411) and Fundamental Research Funds for the Central Universities (XDJK2014D042).Xie, Y.; He, Z.; Zhang, E.; Li, H. (2016). Technical note: Characterization of key volatile odorants in rabbit meat using gas chromatography mass spectrometry with simultaneous distillation extraction. World Rabbit Science. 24(4):313-320. https://doi.org/10.4995/wrs.2016.4464SWORD31332024

Evaluación comparativa de la composición química y las actividades antimicrobianas de los aceites esenciales extraídos de diferentes quimiotipos de Cinnamomum camphora (L.) Presl

The purpose of this study is to determine the chemical composition of the essential oils of Cinnamomum camphora (L.) Presl leaves (CCPL) from 5 different habitats in China by GC-MS, and to evaluate their antimicrobial activities against 3 foodborne pathogens, using a paper disc diffusion method. A total of 30 compounds were identified with a predominance of oxygenated monoterpenes, including linalool (42.65%-96.47%), eucalyptol (39.07%-55.35%) and camphor (26.08%) as well as monoterpene hydrocarbons such as sabinene (6.18%-12.93%) and α-terpineol (8.19%-13.81%). Through cluster analysis, CCPL from 5 different habitats can be well divided into 2 categories. Combining with principal component analysis, the habitats can be better correlated with the chemical constituents of the essential oils. The antimicrobial activities of 5 extracted essential oils against 2 gram-negative bacteria and one gram-positive bacteria were assessed. It showed that the essential oil extracted from the CCPL harvested in Jinxi had the strongest antibacterial property. The results of this study provided basis for resource identification of CCPL and quality difference identification of essential oils. Research on the antibacterial properties of several pathogenic strains has proved its application value as a natural food preservative.El objetivo de este estudio es determinar la composición química de los aceites esenciales de hojas de Cinnamomum camphora (L.) Presl (CCPL) de 5 hábitats diferentes de China mediante GC-MS, y evaluar sus actividades antimicrobianas contra 3 patógenos transmitidos por los alimentos, utilizando un método de difusión de disco de papel. Se identificaron un total de 30 compuestos, con predominio de monoterpenos oxigenados, entre ellos linalol (42,65%-96,47%), eucaliptol (39,07%-55,35%) y alcanfor (26,08%) así como hidrocarburos monoterpenos como el sabineno (6,18%-12,93%) y α-terpineol (8,19%-13,81%). A través del análisis de conglomerados, los CCPL de 5 hábitats diferentes se pueden dividir bien en 2 categorías. En combinación con el análisis de componentes principales, los hábitats se pueden correlacionar mejor con los componentes químicos de los aceites esenciales. Se evaluaron las actividades antimicrobianas de 5 aceites esenciales extraídos contra 2 bacterias gramnegativas y una bacteria grampositiva. Se demuestra que el aceite esencial extraído del CCPL cosechado en Jinxi tenía la propiedad antibacteriana más fuerte. Los resultados de este estudio proporcionaron la base para la identificación de recursos de CCPL y la identificación de diferencias de calidad de los aceites esenciales. La investigación sobre las propiedades antibacterianas de varias cepas patógenas ha demostrado su valor de aplicación como conservante natural de alimentos

The Design and Numerical Study of a 2MWh Molten Salt Thermocline Tank

AbstractThe two tank molten salt thermal storage system is widely used in the commercialized solar thermal power plant. However, the thermocline storage system with a low-cost filler material is a more economically feasible option. In this study, a transient two-dimensional and two-temperature model is developed to investigate the heat transfer and fluid dynamics in a molten salt thermocline thermal storage system. After model validation, the effects of inlet flow boundary condition and storage medium properties including fluid and solid materials on the thermal performance of thermocline storage system are investigated. The results show that thermoclne thickness increases slowest with solar salt as heat transfer fluid (HTF) and Cofalit® as solid material in the thermocline tank. Any non-uniformity in the inlet velocity flow would only enhance mixing and widen the thermocline appreciably, which contributes to the loss of thermodynamic availability of stored energy. The thermocline thickness increases with the non-uniformity of the inlet velocity boundary condition. So smaller non-uniformity of inlet flow is better in non-uniform flow though it may causes larger fluctuations in average outlet temperature. Smaller inlet mass flow rate is better for the thermocline storage tank, while it also causes smaller discharging power. With the chosen basic design parameters such as fluid and solid materials, the size of a 2MWh thermocline tank is determined by a simple one-dimensional design method. Tank with larger H/D ratio has higher discharge efficiency. It helps to figure out the thermal stratification mechanism of a storage tank and thereby to determine optimum design and operating conditions

Few-Body Systems Composed of Heavy Quarks

Within the past ten years many new hadrons states were observed experimentally, some of which do not fit into the conventional quark model. I will talk about the few-body systems composed of heavy quarks, including the charmonium-like states and some loosely bound states.Comment: Plenary talk at the 20th International IUPAP Conference on Few-Body Problems in Physics, to appear in Few Body Systems (2013

The newly observed open-charm states in quark model

Comparing the measured properties of the newly observed open-charm states D(2550), D(2600), D(2750), D(2760), D_{s1}(2710), D_{sJ}(2860), and D_{sJ}(3040) with our predicted spectroscopy and strong decays in a constituent quark model, we find that: (1) the D(2\,^1S_0) assignment to D(2550) remains open for its too broad width determined by experiment; (2) the D(2600) and $D_{s1}(2710)$ can be identified as the 2\,^3S_1-1\,^3D_1 mixtures; (3) if the D(2760) and D(2750) are indeed the same resonance, they would be the D(1\,^3D_3); otherwise, they could be assigned as the D(1\,^3D_3) and $D^\prime_2(1D)$, respectively; (4) the $D_{sJ}(2860)$ could be either the $D_{s1}(2710)$'s partner or the D_s(1\,^3D_3); and (5) both the $D_{s1}(2P)$ and $D^\prime_{s1}(2P)$ interpretations for the $D_{sJ}(3040)$ seem likely. The $E1$ and $M1$ radiative decays of these sates are also studied. Further experimental efforts are needed to test the present quarkonium assignments for these new open-charm states.Comment: 26 pages,7 figures, journal versio

Effect of Intensity Modulator Extinction on Practical Quantum Key Distribution System

We study how the imperfection of intensity modulator effects on the security of a practical quantum key distribution system. The extinction ratio of the realistic intensity modulator is considered in our security analysis. We show that the secret key rate increases, under the practical assumption that the indeterminable noise introduced by the imperfect intensity modulator can not be controlled by the eavesdropper.Comment: 6 pages, 5 figures. EPJD accepte

Studies of Static and Dynamic Characteristics of the EDM Machine Based on the ANSYS Workbench

The static and dynamic characteristics of the EDM machine as the main machining unit directlyinfluence the machining accuracy and stability. For a particular type of the EDM machine, the three-dimensional model was built with SolidWorks and the finite element method was employed with the ANSYS Workbench to analyze the static and dynamic characteristics of the machine. The results show that the stiffness of the ram and vertical guide (Z-axis) in the Y and Z directions is the weak side of the machine. The analytical method is proved to be effective for the optimization of the machine design.Установлено, что точность и стабильность обработки зависят от статических и динамических характеристик электроэрозионного станка как основного станочного модуля. Для электроэрозионного станка определенного типа с помощью программного комплекса SolidWorks была построена трехмерная модель, а для анализа его статических и динамических характеристик использовали метод конечных элементов в комбинации с программным комплексом ANSYS. Результаты показывают, что жесткость ползуна и вертикальной направляющей (ось Z) в направлениях Y и Z слабая сторона станка. Доказано, что аналитический метод является эффективным средством оптимизации его конструкции

Dynamics of quantum Hall stripes in double-quantum-well systems

The collective modes of stripes in double layer quantum Hall systems are computed using the time-dependent Hartree-Fock approximation. It is found that, when the system possesses spontaneous interlayer coherence, there are two gapless modes, one a phonon associated with broken translational invariance, the other a pseudospin-wave associated with a broken U(1) symmetry. For large layer separations the modes disperse weakly for wavevectors perpendicular to the stripe orientation, indicating the system becomes akin to an array of weakly coupled one-dimensional XY systems. At higher wavevectors the collective modes develop a roton minimum associated with a transition out of the coherent state with further increasing layer separation. A spin wave model of the system is developed, and it is shown that the collective modes may be described as those of a system with helimagnetic ordering.Comment: 16 pages including 7 postscript figure

Optical properties of dust

http://arxiv.org/abs/0808.4123Except in a few cases cosmic dust can be studied in situ or in terrestrial laboratories, essentially all of our information concerning the nature of cosmic dust depends upon its interaction with electromagnetic radiation. This chapter presents the theoretical basis for describing the optical properties of dust -- how it absorbs and scatters starlight and reradiates the absorbed energy at longer wavelengths.Partial support by a Chandra Theory program and HST Theory Programs is gratefully acknowledged