Cross Breeding and Hybrid Identification of Sulphite-tolerant Hybrids of Saccharomyces uvarum

Yeast species belonging to Saccharomyces have great potential for the wine industry. However, the sulphite tolerance of most S. uvarum strains is quite poor compared with that of the other Saccharomyces strains. Inorder to get new S. uvarum strains with tolerance to sulphite, and also with good fermentation characteristics, 21 candidates were screened from three different crossing combinations of sensitive S. uvarum strains to one sulphitetolerant strain. Ten of these hybrids were sulphite tolerant and contained the FZF1 gene from both parents. Intersimple sequence repeat (ISSR) analysis confirmed their hybrid status, based on six primers that produced 55 clear and reproducible bands, including 32 that were polymorphic. Two hybrids had identical fingerprints, indicating that it was the same clone. Thus, nine different novel sulphite-resistant hybrids of S. uvarum were obtained. The selected hybrid strains fermented very well at 30ºC in Sauvignon Blanc grape juice containing 2 mM of sodium sulphite, with minor differences in fermentation performance. Two strains (namely C13 and C21) performed very similarly to the sulphite-tolerant parent A9 and a commercial S. cerevisiae strain EC1118, and the production offermentation aromas, namely propanol, isobutanol and isoamyl alcohol by C13 was found to be the highest. This is the first report of using hybridisation to breed the sulphite-tolerant S. uvarum strains

Stability Analysis of Large Scale Integrodifferential Systems

AbstractIn this paper, we investigate the stability problems of large scale integrodifferential systems. The basic idea is first to decompose a large scale system into several appropriate lower order subsystems. Neglecting the interconnection among them, we obtain several isolated subsystems. For each subsystem, a simple method is used to construct a Lyapunov functional to characterize its stability properties. These Lyapunov functionals are then employed in the construction of the Lyapunov functional for the overall system. Unlike ordinary differential systems, simple linear combination of the Lyapunov functional obtained through the stability analysis of the isolated subsystems is no longer a good candidate for the overall integrodifferential system. To overcome this difficulty, we modify the well-known decomposition-aggregation method used for ordinary differential systems and successfully construct, incorporating the special structure of the integral part, the Lyapunov functional or the overall integrodifferential system. Several stability criteria are then established through various aggregation techniques. Since the present approach is constructive, it may be more useful in applications

Rapid analysis of pyrethroid insecticides in aquaculture seawater samples via membrane-assisted solvent extraction coupled with gas chromatography-electron capture detection

A simple, efficient, and environmentally friendly membrane-assisted solvent extraction (MASE) method for the extraction and preconcentration of six pyrethroid insecticides from aquaculture seawater samples followed by gas chromatography-electron capture detection (GC-ECD) was successfully proposed. The operating conditions for MASE, such as the extraction solvent, solvent volume, NaCl concentration, stirring rate, extraction time, and temperature, were optimized. Compared to conventional Florisil-solid phase extraction (SPE), higher extraction recoveries (85.9% to 105.9%) of three spiked levels of the six pyrethroid pesticides in aquaculture seawater were obtained using MASE, and the RSD values were lower than 7.9%. The limits of detection (LOD, signal-to-noise ratio (S/N)=3) and quantification (LOQ, S/N = 10) were in the range of 0.037–0.166 and 0.12–0.55 µg L-1, respectively. The results demonstrate the excellent applicability of the MASE method in analyzing the six pyrethroid pesticides in aqueous samples. The proposed method exhibited a high potential for routine monitoring analysis of pyrethroid insecticides in seawater samples

The simulation of magnetorheological elastomers adaptive tuned dynamic vibration absorber for automobile engine vibration control

The aim of this article is to investigate the use of a Dynamic Vibration Absorber to control vibration of engine by using simulation. Traditional means of vibration control have involved the use of passive and more recently, active methods. This study is different in that it involves an adaptive component in the design of vibration absorber using magnetorheological elastomers (MREs) as the adaptive spring. MREs are kind of novel smart material whose shear modulus can be controlled by applied magnetic field. In this paper, the vibration mode of a simple model of automobile engine is simulated by Finite Element Method (FEM) analysis. Based on the analysis, the MREs Adaptive Tuned Dynamic Vibration Absorber (ATDVA) is presented to reduce the vibration of the engine. Simulation result indicate that the control frequency of ATDVA can be changed by modifing the shear modulus of MREs and the vibraion reduction efficiency of ATDVA are also evaluated by FEM analysis

Effect of Tensor Correlations on Gamow-Teller States in 90Zr and 208Pb

The tensor terms of the Skyrme effective interaction are included in the self-consistent Hartree-Fock plus Random Phase Approximation (HF+RPA) model. The Gamow-Teller (GT) strength function of 90Zr and 208Pb are calculated with and without the tensor terms. The main peaks are moved downwards by about 2 MeV when including the tensor contribution. About 10% of the non-energy weighted sum rule is shifted to the excitation energy region above 30 MeV by the RPA tensor correlations. The contribution of the tensor terms to the energy weighted sum rule is given analytically, and compared to the outcome of RPA.Comment: 13 pages, 2 figures,2 table

Particle Motion Around Tachyon Monopole

Recently, Li and Liu have studied global monoole of tachyon in a four dimensional static space-time. We analyze the motion of massless and massive particles around tachyon monopole. Interestingly, for the bending of light rays due to tachyon monopole instead of getting angle of deficit we find angle of surplus. Also we find that the tachyon monopole exerts an attractive gravitational force towards matter.Comment: 14 pages, 7 figure

Detection of herb-symptom associations from traditional chinese medicine clinical data

YesTraditional Chinese medicine (TCM) is an individualized medicine by observing the symptoms and signs (symptoms in brief) of patients. We aim to extract the meaningful herb-symptom relationships from large scale TCM clinical data. To investigate the correlations between symptoms and herbs held for patients, we use four clinical data sets collected from TCM outpatient clinical settings and calculate the similarities between patient pairs in terms of the herb constituents of their prescriptions and their manifesting symptoms by cosine measure. To address the large-scale multiple testing problems for the detection of herb-symptom associations and the dependence between herbs involving similar efficacies, we propose a network-based correlation analysis (NetCorrA) method to detect the herb-symptom associations. The results show that there are strong positive correlations between symptom similarity and herb similarity, which indicates that herb-symptom correspondence is a clinical principle adhered to by most TCM physicians. Furthermore, the NetCorrA method obtains meaningful herb-symptom associations and performs better than the chi-square correlation method by filtering the false positive associations. Symptoms play significant roles for the prescriptions of herb treatment. The herb-symptom correspondence principle indicates that clinical phenotypic targets (i.e., symptoms) of herbs exist and would be valuable for further investigations

Nucleon-nucleon momentum correlation function for light nuclei

Nucleon-nucleon momentum correlation function have been presented for nuclear reactions with neutron-rich or proton-rich projectiles using a nuclear transport theory, namely Isospin-Dependent Quantum Molecular Dynamics model. The relationship between the binding energy of projectiles and the strength of proton-neutron correlation function at small relative momentum has been explored, while proton-proton correlation function shows its sensitivity to the proton density distribution. Those results show that nucleon-nucleon correlation function is useful to reflect some features of the neutron- or proton-halo nuclei and therefore provide a potential tool for the studies of radioactive beam physics.Comment: Talk given at the 18th International IUPAP Conference on Few-Body Problems in Physics (FB18), Santos, Brasil, August 21-26, 2006. To appear in Nucl. Phys.

A C. elegans neuron both promotes and suppresses motor behavior to fine tune motor output [preprint]

How neural circuits drive behavior is a central question in neuroscience. Proper execution of motor behavior requires the precise coordination of many neurons. Within a motor circuit, individual neurons tend to play discrete roles by promoting or suppressing motor output. How exactly neurons function in specific roles to fine tune motor output is not well understood. In C. elegans, the interneuron RIM plays important yet complex roles in locomotion behavior. Here, we show that RIM both promotes and suppresses distinct features of locomotion behavior to fine tune motor output. This dual function is achieved via the excitation and inhibition of the same motor circuit by electrical and chemical neurotransmission, respectively. Additionally, this bi-directional regulation contributes to motor adaptation in animals placed in novel environments. Our findings reveal that individual neurons within a neural circuit may act in opposing ways to regulate circuit dynamics to fine tune behavioral output