780 research outputs found
RP-LC and HPTLC Methods for the Determination of Olmesartan Medoxomil and Hydrochlorothiazide in Combined Tablet Dosage Forms
Two new, rapid, precise, accurate and specific chromatographic methods were described for the simultaneous determination of olmesartan medoxomil and hydrochlorothiazide in combined tablet dosage forms. The first method was based on reversed phase liquid chromatography using an Eurosphere 100 RP C18 column (250 × 4.6 mm ID, 5 μm). The mobile phase was methanol–0.05% o-phosphoric acid (60:40 v/v) at a flow rate of 1.0 mL min−1. Commercially available tablets and laboratory mixtures containing both drugs were assayed and detected using a UV detector at 270 nm. The second method involved silica gel 60 F254 high performance thin layer chromatography and densitometric detection at 254 nm using acetonitrile–ethyl acetate–glacial acid (7:3:0.4 v/v/v) as the mobile phase. Calibration curves ranged between 200–600 and 125–375 ng spot−1 for olmesartan and hydrochlorothiazide, respectively
Behavior of Poly electrolyte Gels in Concentrated Solutions of Highly Soluble Salts
Ionic hydrogels are an abundant class of materials with applications ranging from drug delivery devices to high performance concrete to baby diapers. A more thorough understanding of interactions between poly electrolyte networks and ionic solutes is critical as these materials are further tailored for performance applications in highly targeted ionic environments. In this work, we seek to develop structure-property relationships between polyelectrolyte gels and environments containing high concentrations of multivalent ions. Specifically, this work seeks to elucidate the causes behind differences in hydrogel response to divalent ions of main group metals versus transition metals. PANa-co-PAM hydrogels containing low and high fractions of ionic groups are investigated in solutions of DI water, NaCl, CaCl2, and CuSO4 at concentrations ranging from 5 to 100 mM in order to understand 1) the transient or permanent nature of crosslinks produced in these networks by divalent counter-ions, 2) the role of polymer ionic content in these interactions, and 3) how these interactions scale with salt concentration. Gravimetric swelling and mechanical compression testing are employed to characterize water and salt-swollen hydrogels in order to develop guiding principles to control and manipulate material properties through polymer-counter-ion interactions. The work presented here confirms the formation of permanent crosslinks by transition metal ions, offers explanation for the behavioral discrepancy observed between ionic hydrogels and main group versus transition metal ions, and illustrates how such hydrogel properties scale with counter-ion concentration
Mode-resolved reciprocal space mapping of electron-phonon interaction in the Weyl semimetal candidate Td-WTe
The selective excitation of coherent phonons provides unique capabilities to
control fundamental properties of quantum materials on ultrafast time scales.
For instance, in the presence of strong electron-phonon coupling, the
electronic band structure can become substantially modulated. Recently, it was
predicted that by this means even topologically protected states of matter can
be manipulated and, ultimately, be destroyed: For the layered transition metal
dichalcogenide Td-WTe, pairs of Weyl points are expected to annihilate as
an interlayer shear mode drives the crystalline structure towards a
centrosymmetric phase. By monitoring the changes in the electronic structure of
Td-WTe with femtosecond resolution, we provide here direct experimental
evidence that the coherent excitation of the shear mode acts on the electronic
states near the Weyl points. Band structure data in comparison with our results
imply, furthermore, the periodic reduction in the spin splitting of bands near
the Fermi energy, a distinct electronic signature of the non-centrosymmetric Td
ground state of WTe. The comparison with higher-frequency coherent phonon
modes finally proves the shear mode-selectivity of the observed changes in the
electronic structure. Our real-time observations reveal direct experimental
insights into electronic processes that are of vital importance for a coherent
phonon-induced topological phase transition in Td-WTe.Comment: 28 pages, 17 figure
Customized television: Standards compliant advanced digital television
This correspondence describes a European Union supported collaborative project called CustomTV based on the premise that future TV sets will provide all sorts of multimedia information and interactivity, as well as manage all such services according to each user’s or group of user’s preferences/profiles. We have demonstrated the potential of recent standards (MPEG-4 and MPEG-7) to implement such a scenario by building
the following services: an advanced EPG, Weather Forecasting, and Stock Exchange/Flight Information
Diffraction effects in the Recoil-Frame Photoelectron Angular Distributions of Halomethanes
Citation: Bomme, C., Anielski, D., Savelyev, E., Boll, R., Erk, B., Bari, S., . . . Rolles, D. (2015). Diffraction effects in the Recoil-Frame Photoelectron Angular Distributions of Halomethanes. 635(11). doi:10.1088/1742-6596/635/11/112020We have measured the Recoil Frame-Photoelectron Angular Distributions (RF-PADs) for inner-shell photoionization of CH3F, CH3I and CF3I halomethane molecules for photoelectron energies up to 300 eV detected within a 4? solid angle in the gas-phase. For high kinetic energies, the RF-PADs are dominated by diffraction effects that encode information on the molecular geometry. © Published under licence by IOP Publishing Ltd
Kyoto: An Integrated System for Specific Domain WSD
This document describes the preliminary release of the integrated Kyoto system for specific domain WSD. The system uses concept miners (Tybots) to extract domain-related terms and produces a domain-related thesaurus, followed by knowledge-based WSD based on wordnet graphs (UKB). The resulting system can be applied to any language with a lexical knowledge base, and is based on publicly available software and resources. Our participation in Semeval task #17 focused on producing running systems for all languages in the task, and we attained good results in all except Chinese. Due to the pressure of the time-constraints in the competition, the system is still under development, and we expect results to improve in the near future
Rheology of enzyme liquefied corn stover slurries: The effect of solids concentration on yielding and flow behavior
The measurement of yield stress and shear thinning flow behavior of slurries formed from unpretreated corn stover at solids loadings of 100–300 g/L provides a key metric for the ability to move, pump, and mix this lignocellulosic slurry, particularly since corn stover slurries represent a major potential feedstock for biorefineries. This study compared static yield stress values and flow hysteresis of corn stover slurries of 100, 150, 200, 250, and 300 g/L, after these slurries were formed by adding pellets to a cellulase enzyme solution (Celluclast 1.5 L) in a fed-batch manner. A rotational rheometer was used to quantitate relative yield stress and its dependence on processing history at insoluble solids concentrations of 4%–21% (wt/vol). Key findings confirmed previous observations that yield stress increases with solids loadings and reaches ~3000 Pa at 25% (wt/vol) solids concentration compared to ~200 Pa after enzyme liquefaction. While optimization of slurry forming (i.e., liquefaction) conditions remains to be done, metrics for quantifying liquefaction extent are needed. The method for obtaining comparative metrics is demonstrated here and shows that the yield stress, shear thinning and shear thickening flow behaviors of enzyme liquefied corn stover slurries can be analyzed using a wide-gap rheometry setup with relative measuring geometries to mimic the conditions that may exist in a mixing vessel of a bioreactor while applying controlled and precise levels of strain
Functional neuroimaging effects of recently discovered genetic risk loci for schizophrenia and polygenic risk profile in five RDoC subdomains
Recently, 125 loci with genome-wide support for association with schizophrenia
were identified. We investigated the impact of these variants and their
accumulated genetic risk on brain activation in five neurocognitive domains of
the Research Domain Criteria (working memory, reward processing, episodic
memory, social cognition and emotion processing). In 578 healthy subjects we
tested for association (i) of a polygenic risk profile score (RPS) including
all single-nucleotide polymorphisms (SNPs) reaching genome-wide significance
in the recent genome-wide association studies (GWAS) meta-analysis and (ii) of
all independent genome-wide significant loci separately that showed sufficient
distribution of all allelic groups in our sample (105 SNPs). The RPS was
nominally associated with perigenual anterior cingulate and posterior
cingulate/precuneus activation during episodic memory (PFWE(ROI)=0.047) and
social cognition (PFWE(ROI)=0.025), respectively. Single SNP analyses revealed
that rs9607782, located near EP300, was significantly associated with amygdala
recruitment during emotion processing (PFWE(ROI)=1.63 × 10−4, surpassing
Bonferroni correction for the number of SNPs). Importantly, this association
was replicable in an independent sample (N=150; PFWE(ROI)<0.025). Other SNP
effects previously associated with imaging phenotypes were nominally
significant, but did not withstand correction for the number of SNPs tested.
To assess whether there was true signal within our data, we repeated single
SNP analyses with 105 randomly chosen non-schizophrenia-associated variants,
observing fewer significant results and lower association probabilities.
Applying stringent methodological procedures, we found preliminary evidence
for the notion that genetic risk for schizophrenia conferred by rs9607782 may
be mediated by amygdala function. We critically evaluate the potential caveats
of the methodological approaches employed and offer suggestions for future
studies
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