7,647 research outputs found
Synergistic Effects of Branched-chain Amino Acids and Phenylalanine Addition on Major Volatile Compounds in Wine during Alcoholic Fermentation
The effects of adding branched-chain amino acids (BCAAs, including L-valine, L-leucine and L-isoleucine),L-phenylalanine and a mixture of them (BCAAs + Phe) on the fermentation profiles of wine yeastEC1118 and the production of volatile compounds were investigated in synthetic grape juice. The additionof selected amino acids had no considerable influence on the yeast growth and primary metabolites of thesugars. Adding BCAAs increased the production of higher alcohols, medium-chain fatty acids (MCFAs)and their corresponding ethyl esters. In comparison, adding Phe promoted the production of 2-phenylethanol,2-phenylethyl acetate and ethyl esters of MCFAs. Nevertheless, the supplementation of BCAAs +Phe further heightened the production of MCFAs, acetate esters and ethyl esters of MCFAs compared tothe single additions, but it attenuated the production of various higher alcohols (1-propanol, 2,3-butanedioland methionol) compared to the addition of BCAAs, and of 2-phenylethanol and 2-phenylethyl acetatecontents compared to the Phe addition. These results suggest that adding BCAAs or Phe is an efficient wayto adjust wine’s aromatic composition and complexity. Meanwhile, the combined addition of BCAAs + Phecould be a potential tool to further manipulate wine’s aromatic profile by accentuating or suppressing theformation of certain aroma compounds
Characteristic Aroma Compounds in Two New Vitis vinifera Cultivars (Table Grapes) and Impact of Vintage and Greenhouse Cultivation
‘Zaoheibao’ (a red tetraploid hybrid) and ‘Wuhecuibao’ (a white triploid hybrid) grapes have beenobtained from Guibao♀ (diploid, Vitis vinifera) × Zaomeigui♂ (diploid, V. vinifera) and Guibao♀ (diploid,V. vinifera) × Wuhebaijixin♂ (triploid, V. vinifera) respectively. Aroma characterisation of the twonew table grape cultivars was firstly done by the investigation of volatile compounds. The influence ofgreenhouse cultivation and vintage on berry aroma was studied as well. The results showed that linalool,decanal, β-damascenone, hexanal and (E)-2-hexenal were the main volatile compounds of the two cultivars,which meant that the floral, fruity and sweet odour were prominent, followed by the herbaceous aroma.Greenhouse cultivation enhanced herbaceous odour in both ‘Wuhecuibao’ and ‘Zaoheibao’ berries,and reduced the floral aroma, contributed mainly by β-damascenone, in ‘Wuhecuibao’, and the sweetaroma, represented mainly by linalool, in ‘Zaoheibao’. The concentrations of the main aroma compoundswere greatly affected by vintage and the intensity of sensorial perception was correspondingly changed,but varietal odour attributes were not significantly altered. These results will not only help promote thecultivation and popularisation of these cultivars, but also will provide valuable data for the use of thesecultivars in future breeding
Improving hand vein recognition by score weighted fusion of wavelet-domain multi-radius local binary patterns
Among biometric modalities, hand vein patterns are seen as providing an attractive method for high-level security access applications owing to high impenetrability and good user convenience. For biometric recognition based on near-infrared dorsal hand vein images, Local Binary Patterns (LBP) have emerged as a highly effective descriptor of local image texture with high recognition performance reported. In this paper, the traditional approach with LBP applied in the spatial domain is extended to multi-radius LBP in the wavelet domain to provide a more comprehensive set of feature categories to capture grey-level variation characteristics of vein patterns, and score weighted fusion based on the relative discriminative power of each feature category is proposed to achieve higher recognition performance. The proposed methodology is shown to provide a more robust performance with a recognition rate in excess of 99% and an equal error rate significantly less than 2%
Application of Lyapunov matrix inequality based unsymmetrical saturated control to a multi-vectored propeller airship
The problem of the design of a controller for a multi-vectored propeller airship is addressed. The controller includes anti-windup that takes into account unsymmetrical actuator constraints. First, a linear transformation is applied to transform the unsymmetrical constraints into symmetric constraints with an amplitude-bounded exogenous disturbance. Then, a stability condition based on a quadratic Lyapunov function for the saturated closed-loop system is proposed. The condition considers both amplitude-bounded and energy-bounded exogenous disturbances. Thus, the controller design problem is transformed into a convex optimization problem expressed in a bilinear matrix inequality form. Two controller design methods were applied: one-step controller and traditional anti-windup controller. The one-step method obtains the controller and the anti-windup compensator in one step while the anti-windup controller method separates this process into the linear controller design and the compensator design. Simulation results showed that both controllers enlarge the stability zone of the saturation system and have good tracking performance. It is shown that the anti-windup controller design method not only has a larger region of stability, but the demanded actuator output exceeds the constraints less and has a smaller anti-windup coefficient matrix compared to the one-step method
Tissue-specific Accumulation of Flavonoids in Grape Berries is Related to Transcriptional Expression of VvF3′H and VvF3′5′H
The products and the related gene expression of flavonoid metabolism were examined in the skin and pulpof Yan73 (Vitis vinifera L. cv.) grapes, a teinturier variety cultivated in China, and the data were comparedwith those in the skin and pulp of Cabernet Sauvignon (Vitis vinifera L. cv.) grapes, a well-known redvariety. The results showed that, in comparison with the skins of Cabernet Sauvignon, the skins of Yan73berries were characterised by fewer types of flavonols and anthocyanins, a higher level of flavonoids,and a much lower percentage of 3′-hydroxylated flavonols. Flavonoid metabolism was also present in thepulp of Yan73, and the percentages of 3′-hydroxylated flavonols and 3′-hydroxylated flavan-3-ols weresignificantly higher than the percentages of their corresponding 3′,5′-hydroxylated forms. Only flavan-3-ols were found in the pulp of Cabernet Sauvignon. The expression of VvmybA1 exhibited a co-ordinationwith the accumulation of anthocyanins in the pulp of the teinturier cultivar, which showed great similarityto that in the skin. A good correlation was found between the expression of VvF3′H and 3′-hydroxylatedflavonoids, as well as between the expression of VvF3′5′H and 3′,5′-hydroxylated flavonoids in the skin andpulp of the grape berries. It is suggested that tissue-specific accumulation of flavonoids in grape berries isrelated to the transcriptional expression of VvF3′H and VvF3′5′H
Quantum three-body system in D dimensions
The independent eigenstates of the total orbital angular momentum operators
for a three-body system in an arbitrary D-dimensional space are presented by
the method of group theory. The Schr\"{o}dinger equation is reduced to the
generalized radial equations satisfied by the generalized radial functions with
a given total orbital angular momentum denoted by a Young diagram
for the SO(D) group. Only three internal variables are
involved in the functions and equations. The number of both the functions and
the equations for the given angular momentum is finite and equal to
.Comment: 16 pages, no figure, RevTex, Accepted by J. Math. Phy
Generation of 3-Dimensional graph state with Josephson charge qubits
On the basis of generations of 1-dimensional and 2-dimensional graph states,
we generate a 3-dimensional N3-qubit graph state based on the Josephson charge
qubits. Since any two charge qubits can be selectively and effectively coupled
by a common inductance, the controlled phase transform between any two-qubit
can be performed. Accordingly, we can generate arbitrary multi-qubit graph
states corresponding to arbitrary shape graph, which meet the expectations of
various quantum information processing schemes. All the devices in the scheme
are well within the current technology. It is a simple, scalable and feasible
scheme for the generation of various graph states based on the Josephson charge
qubits.Comment: 4 pages, 4 figure
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