We classify the constraints on a stationary point of the potential invariant under a finite group into intrinsic and extrinsic based on whether they are independent of the coefficients in the ...potential or not. We find that the symmetry group of a set of stationary points can be larger than that of the potential and the stabilizer under this group generates intrinsic constraints. By applying these findings in the framework of the auxiliary group, we show that the constraints that can only be obtained extrinsically in an elementary theory can be generated intrinsically in an effective theory.
In the framework of the representation theory of finite groups, it was recently shown that a fully constrained complex-symmetric mass matrix can be conveniently mapped into a sextet of Σ (72 × 3). In ...this paper, we introduce an additional flavor group X 24 in the model so that the vacuum alignment of the Σ (72 × 3) sextet is determined not only by the symmetries of Σ (72 × 3) but also by that of X24. We define several flavons which transform as multiplets under Σ (72 × 3) as well as X24. The vacuum alignment of each of these flavons is obtained as a simultaneous invariant eigenstate of specific elements of the groups Σ (72 × 3) and X24 ; i.e., the vacuum alignment is fully determined by its residual symmetries. These flavons couple together uniquely resulting in the fully constrained sextet of Σ (72 × 3). Through this work we propose a general formalism in which the flavor symmetry group (Gf) is obtained as the direct product, Gf = Gr × Gx. Fermions transform nontrivially only under Gr while they remain invariant under Gx. Flavons, on the other hand, transform nontrivially under both Gr and Gx . The vacuum alignment of each flavon multiplet transforming irreducibly under Gr × Gx is uniquely identified by its corresponding residual symmetry (a subgroup of Gr × Gx). Several such flavons couple together to form an effective multiple of Gr which remains invariant under Gx. This effective multiplet couples to the fermions.
•Kinetics and thermodynamics of flavonoid extraction of T. bellerica studied by MAE.•Flavonoid yield improved with microwave irradiation.•MAE of flavonoids were observed to be endothermic and ...spontaneous.•No loss of antioxidant activity due to microwave exposure.
Microwave-assisted solid–liquid extraction (MAE) of flavonoids from Terminalia bellerica Roxb. has been investigated to understand the influence of solvent-to-feed ratio (5–40mL/g) and temperature (40–100°C) on kinetics and thermodynamics of extraction. The flavonoid concentration–time data were analysed using a second order kinetic model to determine extraction constant. A diffusion model was utilized to determine diffusion coefficient taking into account of both washing and diffusion phases together. Solvent-to-feed ratio and temperature were observed to show a significant effect on flavonoid yield, extraction rate and effective diffusion coefficient with the highest solvent-to-feed ratio and temperature providing the maximum flavonoid yield of 25.21mgQE/g using water as the solvent. An empirical equation has been developed to predict extraction kinetics. Thermodynamic parameters revealed MAE process to be spontaneous and endothermic. The kinetic and diffusion models provided valuable insights into the microwave assisted extraction process. T. bellerica was observed to be a good source of flavonoids. Therefore, MAE is a suitable method for extraction of flavonoids from T. bellerica when water alone is to be used as the solvent, as in the case of traditional Indian medicinal preparations.
Manufacturers and online retailers are readily availing themselves of new technologies to present their merchandise using a variety of formats, including static (still image) and dynamic (video) ...portrayal. Building on vividness theory, the authors propose and demonstrate that presenting products and services using a dynamic visual format enhances consumer preference for hedonic options and willingness to pay for those options. The dynamic presentation format increases involvement with the product/service experience in a manner presumably similar to that of the actual product experience. The result is an increased preference for and valuation of hedonic options. This holds true for experiential and search products in single and joint evaluations and carries over to subsequent choices. Across all studies, the results demonstrate that a dynamic (relative to static) presentation format enhances choice of the hedonically superior (vs. utilitarian-superior) option by more than 79%.
Recent trends, variations and tele-connections between the two large regional sub-systems over the Asian domain, the South Asian and the East Asian monsoons are explored using data for the 1901–2014 ...period. Based on trend analysis a dipole-type configuration with north-drought and south-flood over South as well as East Asia is observed. Two regions over South Asia, one exhibiting a significant decreasing trend in summer monsoon rainfall over northeast India and the other significant increasing trend over the northern parts of the west coast of India are identified. Similarly two regions over East Asia, one over South Korea-southern parts of Japan and the other over South China are also identified both indicating a significant increasing trend in the summer monsoon rainfall. These trends are examined post 1970s. Possible factors associated with the recent trends are explored. Analysis of sea surface temperature (SST), mean sea level pressure and winds at lower troposphere indicates that the entire monsoon flow system appears to have shifted westwards, with the monsoon trough over South Asia indicating a westward shift by about 2–3° longitudes and the North Pacific Subtropical High over East Asia seems to have shifted by about 5–7° longitudes. These shifts are consistent with the recent rainfall trends. Furthermore, while the West Indian Ocean SSTs appear to be related with the summer monsoon rainfall over northern parts of India and over North China, the West Pacific SSTs appear to be related with the rainfall over southern parts of India and over South Korea- southern Japan sector.
Although there have been no cases of serotype 2 wild poliovirus for more than 20 years, transmission of serotype 2 vaccine-derived poliovirus (VDPV2) and associated paralytic cases in several ...continents represent a threat to eradication. The withdrawal of the serotype 2 component of oral poliovirus vaccine (OPV2) was implemented in April 2016 to stop VDPV2 emergence and secure eradication of all serotype 2 poliovirus. Globally, children born after this date have limited immunity to prevent transmission. Using a statistical model, we estimated the emergence date and source of VDPV2s detected between May 2016 and November 2019. Outbreak response campaigns with monovalent OPV2 are the only available method to induce immunity to prevent transmission. Yet our analysis shows that using monovalent OPV2 is generating more paralytic VDPV2 outbreaks with the potential for establishing endemic transmission. A novel OPV2, for which two candidates are currently in clinical trials, is urgently required, together with a contingency strategy if this vaccine does not materialize or perform as anticipated.
Schizophrenia is associated with impairments in neurotransmitter systems and changes in neuronal membrane phospholipids. Several atypical antipsychotic drugs induce weight gain and ...hypertriglyceridemia. To date, there has not been a comprehensive evaluation and mapping of global lipid changes in schizophrenia, and upon treatment with antipsychotics. Such mapping could provide novel insights about disease mechanisms and metabolic side effects of therapies used for its treatment. We used a specialized metabolomics platform 'lipidomics' that quantifies over 300 polar and nonpolar lipid metabolites (across seven lipid classes) to evaluate global lipid changes in schizophrenia and upon treatment with three commonly used atypical antipsychotics. Lipid profiles were derived for 50 patients with schizophrenia before and after treatment for 2-3 weeks with olanzapine (n=20), risperidone (n=14) or aripiprazole (n=16). Patients were recruited in two cohorts (study I, n=27 and study II, n=23) to permit an internal replication analyses. The change from baseline to post-treatment was then compared among the three drugs. Olanzapine and risperidone affected a much broader range of lipid classes than aripiprazole. Approximately 50 lipids tended to be increased with both risperidone and olanzapine and concentrations of triacylglycerols increased and free fatty acids decreased with both drugs but not with aripiprazole. Phosphatidylethanolamine concentrations that were suppressed in patients with schizophrenia were raised by all three drugs. Drug specific differences were also detected. A principal component analysis (PCA) identified baseline lipid alterations, which correlated with acute treatment response. A more definitive long-term randomized study of these drugs correlating global lipid changes with clinical outcomes could yield biomarkers that define drug-response phenotypes.
General Strategies for Nanoparticle Dispersion Mackay, Michael E; Tuteja, Anish; Duxbury, Phillip M ...
Science (American Association for the Advancement of Science),
03/2006, Letnik:
311, Številka:
5768
Journal Article
Recenzirano
Traditionally the dispersion of particles in polymeric materials has proven difficult and frequently results in phase separation and agglomeration. We show that thermodynamically stable dispersion of ...nanoparticles into a polymeric liquid is enhanced for systems where the radius of gyration of the linear polymer is greater than the radius of the nanoparticle. Dispersed nanoparticles swell the linear polymer chains, resulting in a polymer radius of gyration that grows with the nanoparticle volume fraction. It is proposed that this entropically unfavorable process is offset by an enthalpy gain due to an increase in molecular contacts at dispersed nanoparticle surfaces as compared with the surfaces of phase-separated nanoparticles. Even when the dispersed state is thermodynamically stable, it may be inaccessible unless the correct processing strategy is adopted, which is particularly important for the case of fullerene dispersion into linear polymers.
Naturally-occurring membrane proteins have been engineered as nanopore sensors for the single-molecule detection of various biochemical molecules. Here, we present a natural bacterial porin, CymA ...containing a dynamic component and densely packed charged residues in the pore, shaping a unique structural conformation and charge feature. Using single-channel recordings, we investigated the translocation of charged polypeptides through native CymA and truncated CymA lacking the dynamic element. Cationic polypeptides bind to the pore with high affinity, specifically at low salt conditions indicating an electrostatic charge and voltage-dependent translocation. Anionic peptides did not bind to the pore, confirming the selective binding of polypeptides with the pore due to their specific charge distribution. Further, the distinct peptide translocation kinetics between native and truncated indicated the role of the dynamic segment in molecular transport. We suggest that these natural membrane pores that permit the selective translocation of cationic polypeptides are advantageous for nanopore proteomics applications.
We have developed a metal-free, mild, and green synthetic route toward benzothieno3,2-bbenzofurans by the annulation of 3-nitrobenzothiophene with phenols. The reaction was found to be general with ...a range of substituted phenols. In addition, we could extend the methodology for the synthesis of pentacenes and could demonstrate the synthesis in gram-scale. Moreover, we extended the strategy for the synthesis of benzothieno2,3-bbenzofurans by starting from 2-nitrobenzothiophenes.
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