•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%.
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.
We construct a neutrino model using the flavour group
S
4
×
C
4
×
C
3
×
C
2
under the type 1 seesaw mechanism. The vacuum alignments of the flavons in the model lead to
TM
1
mixing with
sin
θ
13
=
1
...3
sin
π
12
. The mixing also exhibits
μ
-
τ
reflection symmetry. By fitting the eigenvalues of the effective seesaw mass matrix with the observed neutrino mass-squared differences, we predict the individual light neutrino masses. The vacuum alignment of the
S
4
triplet appearing in the Majorana mass term plays a key role in obtaining the aforementioned
TM
1
scenario. Since the symmetries of the flavour group are not sufficient to define this alignment, we apply the recently proposed framework of the auxiliary group in our model. Using this framework, the
S
4
triplet is obtained by coupling together several irreducible multiplets that transform under an expanded flavour group consisting of the original flavour group as well as an auxiliary group. The vacuum alignment of each of these multiplets is uniquely defined in terms of its residual symmetries under the expanded flavour group. As a result, the
S
4
triplet constructed from these multiplets also becomes uniquely defined.
The structural and thermal properties of sodium niobium phosphate glass are studied to analyse its suitability for immobilizing long-lived radioactive waste from nuclear reprocessing plants. Two ...series of sodium niobium phosphate glasses such as (A)
x
Nb
2
O
5
–(50−
x
)Na
2
O–50P
2
O
5
and (B)
x
Nb
2
O
5
–(50−
x
/
2)Na
2
O–(50−
x
/
2) P
2
O
5
(
x
= 0, 10, 20, 30, 40 mol.%) are prepared by the conventional melt–quenching technique. The influence of the incremental addition of Nb
2
O
5
on the structural and thermal properties of the above two series is investigated. The FTIR and Raman spectra of these glasses revealed that the number of NbO
6
octahedral chain increases with Nb content and dominates as the major structural unit over the number of PO
4
tetrahedra unit. The glass transition temperature (
T
g
), crystallization temperature (
T
c
) and melting temperature (
T
m
) are measured by using a differential scanning calorimeter (DSC). Other thermal stability parameters such as Hruby (
K
H
), Angell (
K
A
), Saad–Poulain (
K
SP
) and Weinberg (
K
W
), the total relaxation time of transformation and fragility are evaluated and compared between different composition of glasses. For both series A and B, the glass transition temperature increases with Nb content, suggesting the formation of a larger number of P–O–Nb or Nb–O–Nb linkages compared to the PO
4
tetrahedra, resulting in a more rigid network. This is confirmed by Raman spectra which show an increase in the number of Nb–O–Nb bonds with Nb content. The major crystalline phases formed by devitrifying these glasses are identified by XRD and are found to be mainly NaPO
3
, NbOPO
4
, Na
2
Nb
6
P
4
O
26
and Na
4
Nb
8
P
4
O
32
.
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