Effects of (-)-epigallocatechin gallate and quercetin on the activity and structure of α-amylase

Purpose: To investigate the effects of (-)-epigallocatechin gallate (EGCG) and quercetin on the activity and structure of α-amylase. Methods: The inhibitory effects of 7 functional factors were compared by measuring half maximal inhibitory concentration (IC50) values. Lineweaver-Burk plots were used to determine the type of inhibition exerted by EGCG and quercetin against α-amylase. The effect of EGCG and quercetin on the conformation of α-amylase was investigated using fluorescence spectroscopy. Results: Quercetin and EGCG inhibited α-amylase with IC50 values of 1.36 and 0.31 mg/mL, respectively, which were much lower than the IC50 values of the other compounds (puerarin, paeonol, konjac glucomannan and polygonatum odoratum polysaccharide). The Lineweaver−Burk plots indicated that EGCG and quercetin inhibited α-amylase competitively, with ki values of 0.23 and 1.28 mg/mL, respectively. Fluorescence spectroscopy revealed that treatment with EGCG and quercetin led to formation of a loosely-structured hydrophobic hydration layer. Conclusion: This study has unraveled the mechanism underlying the inhibition of α-amylase activity by EGCG and quercetin in vitro. This should make for better understanding of the mechanisms that underlie the antidiabetic effects of EGCG and quercetin in vivo

Cloning and expression of the VvbHLH79 gene involved in grape tartaric acid biosynthesis

Abstract [Objective] Tartaric acid not only affects the taste of grape berries but also determines the color, texture, microbial stability, and aging potential of the wine. It is of great value to explore the transcription factors and mechanisms that regulate tartaric acid biosynthesis, regulate the accumulation of tartaric acid in grapes through biotechnology or to cultivate wine grape varieties with high tartaric acid accumulation. [Methods] In this study, using ‘Traminer’ and ‘Marselan’ wine grapes as experimental materials, we cloned the tartaric acid related transcription factor VvbHLH79 by PCR. We performed bioinformatic and subcellular localization analyses of VvbHLH79. Furthermore, we measured the tartaric acid content and VvbHLH79 expression levels in grape berries at different developmental stages using HPLC and qRTPCR techniques. We also constructed a plant expression vector and the expression and tartaric acid content of VvbHLH79 were detected after transient transformation of young grape berries using Agrobacteriummediated fruiting pedicle infection, in order to clarify the role of the VvbHLH79 gene in regulating the content of tartaric acid in grape berries. [Results] (1) A grapevine VvbHLH79 gene was obtained by RNA-seq, with a CDS of 831 bp, amino acids of 277, molecular weight of 66.22 kD, and isoelectric point of 5.15. It belonged to the class of unstable hydrophilic proteins without signal peptides and transmembrane structures. Positions 147-232 of amino acid sequence contained the bHLH-SF conserved domain, which belonged to the bHLH transcription factor family. The protein was localized in the cell nucleus. (2) The grapevine VvbHLH79-encoded protein had the highest sequence similarity with the bHLH89-encoded protein in riverbank grape (accession number: XP_034699340.1), with a sequence identity of 99.64%. (3) There was a gradual decrease of VvbHLH79 expression during the development of ‘Traminer’ grape fruits, decreasing 67.25% from veraison to harvest. The accumulation of tartaric acids occurred mainly before color change of the grapes, with a rapid decrease after color change. (4) Transient expression of VvbHLH79 in low tartaric acid grapes resulted in a increase in tartaric acids, whereas silencing of VvbHLH79 in high tartaric acid grapes resulted in a decrease in tartaric acids, confirming that the VvbHLH79 gene positively regulated tartaric acid content. [Conclusion] The VvbHLH79 transcription factor may play a role in the tartaric acid biosynthesis in grape berries

Soft switching modulation strategy based on bipolar (PSM) with improved efficiency in high-frequency link inverters

High Frequency-Link (HFL) Inverters have been employed to integrate renewable energy sources into utility grids and electric vehicles. The soft-switching range of High-Frequency Link Inverters (HFLI) is increased using auxiliary inductors and capacitors. The application of auxiliary components increases the conduction loss and the complexity of the circuit. The literature indicates that the existing soft-switching methods suffer from higher duty cycle loss, voltage spikes, and lower efficiency owing to the resonance between the parasitic capacitance of switches and the leakage inductance of the transformer. Therefore, it is imperative to develop a modulation strategy that can improve the efficiency of HFLI. In this context, the proposed study develops a cycloconverter-type High-Frequency Link Inverter (CHFLI) based on a Bipolar Phase Shift Modulation (BPSM) strategy without the use of auxiliary components. The proposed modulation strategy enables the semiconductor switches to operate under zero voltage switching. The full-bridge inverter and Full Bridge Active Clamper Circuit (FBAC) switches operate at the same gating signals with a constant duty cycle of 50%. The proposed topology uses built-in magnetizing inductance to achieve zero voltage switching and reduce the duty cycle loss. The leakage energy is recycled from the output filter inductor to the load side using the FBAC. The results indicate that the proposed modulation strategy achieves ZVS and simultaneously achieves an efficiency of 95%. The proposed modulation strategy is easy to implement and does not require complex circuitry

Logarithmic corrections from ferromagnetic impurity ending bonds of open antiferromagnetic host chains

We analyze the logarithmic corrections due to ferromagnetic impurity ending bonds of open spin 1/2 antiferromagnetic chains, using the density matrix renormalization group technique. A universal finite size scaling $\sim {\frac 1 {L \log L}}$ for impurity contributions in the quasi-degenerate ground state energy is demonstrated for a zigzag spin 1/2 chain at the critical next nearest neighbor coupling and the standard Heisenberg spin 1/2 chain, in the long chain limit. Using an exact solution for the latter case it is argued that one can extract the impurity contributions to the entropy and specific heat from the scaling analysis. It is also shown that a pure spin 3/2 open Heisenberg chain belongs to the same universality class.Comment: 4 pages, 7 eps figure

Geochemical reactions altering the mineralogical and multiscale pore characteristics of uranium-bearing reservoirs during CO2 + O2in situ leaching

CO2 + O2in situ leaching has been extensively applied in uranium recovery in sandstone-type uranium deposits of China. The geochemical processes impact and constrain the leaching reaction and leaching solution migration; thus, it is necessary to study the CO2 + O2–water–rock geochemical reaction process and its influence on the physical properties of uranium-bearing reservoirs. In this work, a CO2 + O2–water–rock geochemical reaction simulation experiment was carried out, and the mineralogical and multiscale pore characteristics of typical samples before and after this simulation experiment were compared by X-ray diffraction and high-pressure mercury intrusion porosimetry (HPMIP). The results show that the CO2 + O2–water–rock geochemical reaction has complicated effects on the mineral compositions due to the various reaction modes and types. After the CO2 + O2–water–rock geochemical reaction, the femic minerals decrease and the clay minerals in the coarse sandstone, medium sandstone, fine sandstone, and siltstone increase, while the femic minerals and clay minerals in sandy mudstone show a contrary changing trend. The CO2 + O2–water–rock geochemical reaction decreases the total pore volume of uranium-bearing reservoirs and then promotes pore transformation from small scale to large scale. The fractal dimensions of macropores are decreased, and the fractal dimensions of mesopores, transition pores, and micropores are increased. The effects of felsic mineral and carbonate dissolution, secondary mineral precipitate, clay mineral swelling, and mineral particle migration are simultaneously present in the CO2 + O2in situ leaching process, which exhibit the positive transformation and the negative transformation for the uranium-bearing reservoirs. The mineral dissolution may improve reservoir permeability to a certain degree, while the siltation effect will gradually reveal with the extension of CO2 + O2in situ leaching. This research will provide a deep understanding of the physical property response of uranium-bearing reservoirs during CO2 + O2in situ leaching and indicate the direction for the efficient recovery of uranium resources

Genetic variation and marker−trait association affect the genomic selection prediction accuracy of soybean protein and oil content

IntroductionGenomic selection (GS) is a potential breeding approach for soybean improvement.MethodsIn this study, GS was performed on soybean protein and oil content using the Ridge Regression Best Linear Unbiased Predictor (RR-BLUP) based on 1,007 soybean accessions. The SoySNP50K SNP dataset of the accessions was obtained from the USDA-ARS, Beltsville, MD lab, and the protein and oil content of the accessions were obtained from GRIN.ResultsOur results showed that the prediction accuracy of oil content was higher than that of protein content. When the training population size was 100, the prediction accuracies for protein content and oil content were 0.60 and 0.79, respectively. The prediction accuracy increased with the size of the training population. Training populations with similar phenotype or with close genetic relationships to the prediction population exhibited better prediction accuracy. A greatest prediction accuracy for both protein and oil content was observed when approximately 3,000 markers with -log10(P) greater than 1 were included.DiscussionThis information will help improve GS efficiency and facilitate the application of GS