Myostatin preferentially down-regulates the expression of fast 2x myosin heavy chain in cattle

Myostatin is involved in an inhibitor of muscular growth and differentiation. Myoblasts derived from double-muscled Japanese shorthorn cattle (DM myoblasts) with absence of functional myostatin had higher abilities to proliferate and differentiate than myoblasts derived from normal-muscled cattle (NM myoblasts). In DM myoblasts, mRNA expressions of fetal myosin heavy chain (MyHC) in growth medium and of fast 2a and 2x MyHC in fusion medium were significantly greater than that in NM myoblasts. No significant difference existed in expressions of embryonic and slow MyHC mRNA between DM and NM myoblasts. The expression of MyoD mRNA was suppressed in myoblasts by administration of myostatin. Two cloned DM myoblast strains (DMc) were established. Addition of myostatin for DMc resulted in less myotube formation and suppression of mRNA expression of fast 2x MyHC. These findings suggest that the endogenous myostatin preferentially down-regulates the expression of the fast 2x MyHC and participates in differentiation of myofiber types during early bovine myogenesis.     

Microscale Numerical Simulation of the Permeability Reduction due to Trapping of Suspended Fine Particles Within Sand Sediments

The reduction in permeability of sediments due to blockages caused by the trapping of suspended particles is a common concern for the extraction processes of oil or natural gas. In this study, the effect of trapped fine particles in sand sediments is studied numerically using a three-dimensional lattice Boltzmann method. The geometrical properties of larger, immobile, sand grains are digitally extracted by the spherical harmonics series expansions of CT scans of real sand grains. The migrating fine particles are assumed to be spherical in shape with their volumes following a log-normal distribution. These fine particles, together with larger frame sands, are positioned, without overlapping, within a microscopic, cubic, domain with periodic boundaries. The remaining empty volume is filled with water and imposing a pressure gradient simulates the flow of fluid through the sediment. As a result of fine particles becoming trapped by the frame sand, the initial porosity of which is 0.589, the absolute permeability of the system is reduced by approximately 60?C90?%, corresponding to fine particle saturations of 0.15?C0.29, respectively. The permeability change due to the trapping of fine particles is also modelled theoretically using not only volume saturations but also specific surface areas of both the frame sands and the fine particles with a coefficient of proportionality.     

Fusing C<Subscript>60</Subscript> units without Stone–Wales bond rotations

Abstract  Using ab-initio calculation, we have explored new chemical paths for the coalescence of C₆₀ units into higher fullerenes and novel structures. Besides the Stone–Wales paradigm used for rationalizing the fusion of fullerenes and nanotubes, we demonstrated that an alternative path exists for the fusion of two C₆₀ units. This path uses successive “π–π” additions and subsequent bond reorganizations to lead to a specific C₁₂₀ peanut-like structure. The energies of the chemical barriers, the intermediate structures, and the final product are markedly lower than their counterparts found in the chemical paths based on Stone–Wales bond rotations. The results rationalize the existence of a temperature range in which peanut-like structures are obtained during thermal treatment of peapod structures. Graphical abstract   Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Efficient Amide Bond Formation through a Rapid and Strong Activation of Carboxylic Acids in a Microflow Reactor

The development of highly efficient amide bond forming methods which are devoid of side reactions, including epimerization, is important, and such a method is described herein and is based on the concept of rapid and strong activation of carboxylic acids. Various carboxylic acids are rapidly (0.5 s) converted into highly active species, derived from the inexpensive and less‐toxic solid triphosgene, and then rapidly (4.3 s) reacted with various amines to afford the desired peptides in high yields (74 %–quant.) without significant epimerization (≤3 %). Our process can be carried out at ambient temperature, and only CO₂ and HCl salts of diisopropylethyl amine are generated. In the long history of peptide synthesis, a significant number of active coupling reagents have been abandoned because the highly active electrophilic species generated are usually susceptible to side reactions such as epimerization. The concept presented herein should renew interest in the use of these reagents.     

Chemical constituents of the aerial parts of Scutellaria lateriflora and their alpha-glucosidase inhibitory activities

MeOH extracts of 37 herbs were tested in screening experiments for rat intestinal alpha-glucosidase. The MeOH extract of the aerial parts of Scutellaria lateriflora L. (Lamiaceae) significantly inhibited sucrase and maltase activities, using sucrose and maltase as the substrates. Enzyme inhibition guided-fractionation of the MeOH extract of S. lateriflora resulted in the isolation of a new diterpene glucoside, deacetylajugarin-IV 18-O-beta-D-glucopyranoside (1), along with 20 known phenolics (2-21). The structures of 1-21 were elucidated on the basis of MS and NMR data analyses. Baicalein (4) and baicalin (10), a glycoside of 4, showed moderate sucrase inhibitory activities at IC50 values of 14.9 and 36.3 microM, respectively, whereas luteolin (3), acteoside (16), leucosceptoside A (18), and isoacteoside (20) showed weak inhibitory activities at IC50 values of 811, 522, 727, and 443 microM, respectively. This is the first report on mammalian alpha-glucosidase inhibitory activities of S. lateriflora extract and identification of the constituents responsible for the activities. Apigenin (2), luteolin (3), 6-methoxyluteolin 4'-methyl ether (6), isoscutellarin 8-O-beta-D-glucuronide (7), luteolin 7-O-beta-D-glucuronide (9), wogonin 7-O-beta-D-glucuronide methyl ester (12), eriodictyol (13), naringenin (14), naringenin 7-O-beta-D-glucuronide (15), jionoside D (17), leucosceptoside A (18), and (+)-syringaresinol 4'-O-beta-D-glucopyranoside (21) were isolated from this plant for the first time. The inhibitory properties of S. lateriflora extract against alpha-glucosidase provide a prospect for its antidiabetic usage.     

Approximate Bayesian Computation and Model Assessment for Repulsive Spatial Point Processes

In many applications involving spatial point patterns, we find evidence of inhibition or repulsion. The most commonly used class of models for such settings are the Gibbs point processes. A recent alternative, at least to the statistical community, is the determinantal point process. Here, we examine model fitting and inference for both of these classes of processes in a Bayesian framework. While usual MCMC model fitting can be available, the algorithms are complex and are not always well behaved. We propose using approximate Bayesian computation (ABC) for such fitting. This approach becomes attractive because, though likelihoods are very challenging to work with for these processes, generation of realizations given parameter values is relatively straightforward. As a result, the ABC fitting approach is well-suited for these models. In addition, such simulation makes them well-suited for posterior predictive inference as well as for model assessment. We provide details for all of the above along with some simulation investigation and an illustrative analysis of a point pattern of tree data exhibiting repulsion. R code and datasets are included in the supplementary material.     

Simultaneous determination of gemfibrozil and its metabolites in plasma and urine by a fully automated high performance liquid chromatographic system

Sensitive and specific methods for the simultaneous determination of gemfibrozil (Lopid), a lipid-lowering agent, and its metabolites in plasma and urine are described. The methods are based on a fully automated high performance liquid chromatographic (HPLC) system with fluorescence detection. Urine samples, diluted with acetonitrile, were directly analysed by HPLC using a flow and eluent programming method. In the case of plasma, gemfibrozil and its main metabolites were extracted from acidified samples and the resulting extracts injected into the chromatographic system. The sensitivity was approximately 100 ng/mL for gemfibrozil and its four metabolites using 0.5 mL plasma or urine. An acyl glucuronide of gemfibrozil excreted in human urine after oral administration of the drug was isolated and its structure and stability examined.     

Rapid Synthesis of Thiophene‐Based,Organic Dyes for Dye‐Sensitized Solar Cells (DSSCs) by a One‐Pot,Four‐Component Coupling Approach

This one‐pot, four‐component coupling approach (Suzuki–Miyaura coupling/C?H direct arylation/Knoevenagel condensation) was developed for the rapid synthesis of thiophene‐based organic dyes for dye‐sensitized solar cells (DSSCs). Seven thiophene‐based, organic dyes of various donor structures with/without the use of a 3,4‐ethylenedioxythiophene (EDOT) moiety were successfully synthesized in good yields based on a readily available thiophene boronic acid pinacol ester scaffold (one‐pot, 3‐step, 35–61 %). Evaluation of the photovoltaic properties of the solar cells that were prepared using the synthesized dyes revealed that the introduction of an EDOT structure beside a cyanoacrylic acid moiety improved the short‐circuit current (J_sc) while decreasing the fill factor (FF). The donor structure significantly influenced the open‐circuit voltage (V_oc), the FF, and the power conversion efficiency (PCE). The use of a n‐hexyloxyphenyl amine donor, and our originally developed, rigid, and nonplanar donor, both promoted good cell performance (η=5.2–5.6 %).     

Theoretical study on the photochromic cycloreversion reactions of dithienylethenes; on the role of the conical intersections

The mechanism of the photochromic cycloreversion reactions is theoretically examined in a model system of dithienylethenes by means of the CASSCF and CASPT2 methods. The structures of its conical intersections (CIs), which are the branching points of the internal conversions, were obtained. The analyses of the minimum energy paths from the Franck-Condon states and the CI points suggest that the cycloreversion reaction occurs during the intramolecular vibrational energy redistribution (IVR) toward the quasi-equilibrium on the 2A state. The current study of the model system will provide a basic insight for the photochromic molecular design.     

Theoretical studies to understand surface chemistry on carbon anodes for lithium-ion batteries: how does vinylene carbonate play its role as an electrolyte additive?

To elucidate the role of vinylene carbonate (VC) as a solvent additive in organic polar solutions for lithium-ion batteries, reductive decompositions for vinylene carbonate (VC) and ethylene carbonate (EC) molecules have been comprehensively investigated both in the gas phase and in solution by means of density functional theory calculations. The salt and solvent effects are incorporated with the clusters (EC)nLi+(VC) (n = 0-3), and further corrections that account for bulk solvent effects are added using the polarized continuum model (PCM). The electron affinities of (EC)nLi+(VC) (n = 0-3) monotonically decrease when the number of EC molecules increases; a sharp decrease of about 20.0 kcal/mol is found from n = 0 to 1 and a more gentle variation for n > 1. For (EC)nLi+(VC) (n = 1-3), the reduction of VC brings about more stable ion-pair intermediates than those due to reduction of the EC molecule by 3.1, 6.1, and 5.3 kcal/mol, respectively. This finding qualitatively agrees with the experimental fact that the reduction potential of VC in the presence of Li salt is more negative than that of EC. The calculated reduction potentials corresponding to radical anion formation are close to the experimental potentials determined with cyclic voltammetry on a gold electrode surface (-2.67, -3.19 eV on the physical scale for VC and EC respectively vs experimental values -2.96 and -2.94 eV). Regarding the decomposition mechanisms, the VC and EC moieties undergo homolytic ring opening from their respective reduction intermediates, and the energy barrier of VC is about one time higher than that of EC (e.g., 20.1 vs 8.8 kcal/mol for (EC)2Li+(VC)); both are weakly affected by the explicit solvent molecules and by a bulk solvent represented by a continuum model. Alternatively, starting from the VC-reduction intermediate, the ring opening of the EC moiety via an intramolecular electron-transfer transition state has also been located; its barrier lies between those of EC and VC (e.g., 17.2 kcal/mol for (EC)2Li+(VC)). On the basis of these results, we suggest the following explanation about the role that VC may play as additive in EC-based lithium-ion battery electrolytes; VC is initially reduced to a more stable intermediate than that from EC reduction. One possibility then is that the reduced VC decomposes to form a radical anion via a barrier of about 20 kcal/mol, which undergoes a series of reactions to give rise to more active film-forming products than those resulting from EC reduction, such as lithium divinylene dicarbonate, Li-C carbides, lithium vinylene dicarbonate, R-O-Li compound, and even oligomers with repeated vinylene and carbonate-vinylene units. Another possibility starting from the VC-reduction intermediate is that the ring opening occurs on the unreduced EC moiety instead of being on the reduced VC, via an intramolecular electron transfer transition state, the energy barrier of which is lower than that of the former, in which VC just helps the intermediate formation and is not consumed. The factors that determine the additive functioning mechanism are briefly discussed, and consequently a general rule for the selection of electrolyte additive is proposed.