Search results for "Kinetics"

Conformational-Dependent Photodissociation of Glycolic Acid in an Argon Matrix

2023

Ultraviolet-induced photodissociation and photo-isomerization of the three most stable conformers (SSC, GAC, and AAT) of glycolic acid are investigated in a low-temperature solid argon matrix using FTIR spectroscopy and employing laser radiation with wavelengths of 212 nm, 226 nm, and 230 nm. The present work broadens the wavelength range of photochemical studies of glycolic acid, thus extending the understanding of the overall photochemistry of the compound. The proposed kinetic model for the photodissociation of glycolic acid proceeds from the lowest energy conformer (SSC). The model suggests that ultraviolet light induces isomerization only between the SSC and GAC conformers and between …

Editorial: Flavonoids: From Biosynthesis and Metabolism to Health Benefits

2021

descripción no proporcionada por scopus

In Vitro Evaluation of Poly(lactide-co-glycolide) In Situ Forming Gels for Bedaquiline Fumarate Salt and Pharmacokinetics Following Subcutaneous Inje…

2021

This study evaluated in vitro and in vivo drug release of bedaquiline from in situ forming gels (ISGs) containing 200 mg eq./g bedaquiline fumarate salt prepared with four different grades of poly(d,l-lactide) (PDLLA) or poly(d,l-lactide-co-glycolide) (PLGA) with a lactide/glycolide ratio of 50/50 or 75/25 and acid (A) or ester (E) end-capping in N-methyl-2-pyrrolidone at a polymer/solvent ratio of 20/80% (w/w). Mean in vitro drug release in 0.05 M phosphate buffer pH 7.4 with 1% (w/v) sodium lauryl sulphate was 37.3, 47.1, 53.3, and 62.3% within 28 days for ISGs containing PLGA5050A, PDLLA, PLGA7525A, and PLGA7525E, respectively. The data suggested that drug release was primarily controlle…

Equilibrium and studies on sorption of heavy metals from solutions by algae

2013

Second harmonic ac polarography of strongly adsorbed electroactive species

1981

Abstract The second harmonic ac current is calculated for the case of a quasi-reversible surface redox system: both species are strongly adsorbed according to a Langmuir isotherm and the kinetics of the process are controlled by the electron transfer. The current is measured with a phase-sensitive detector and the variation of the in-phase and quadrature components vs. the frequency leads to the surface rate constant ks. The experimental results obtained for benzo-(c)cinnoline are in good agreement with the theoretical predictions and with the results of impedance measurements. The advantages of the two methods are compared.

Thermal and thermo-oxidative stability and kinetics of decomposition of PHBV/sisal composites

2017

The decomposition behaviours of composites made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and sisal were assessed in terms of thermal stability and decomposition kinetics, under inert and oxidative conditions, by means of multi-rate linear non-isothermal thermogravimetric experiments. A statistical design of experiments was applied to study the influence of the addition of sisal (0-10-20-30%wt), the presence coupling agent (Yes/No) and the applied conditions of work (inert or oxidative). An improvement of the thermal and thermo-oxidative stability of PHBV with the addition of sisal was observed for all cases. An accurate methodology based on iso-conversional methods was applied…

Latvijas rūpniecībai aktuālu farmaceitiski aktīvo vielu kristālsolvāti

2013

ANOTĀCIJA Promocijas darbs veltīts Latvijas tautsaimniecībai aktuālu farmaceitiski aktīvo vielu (FAV) izpētei. Veikti apskatīto vielu kristālsolvātu meklējumi un iegūtas līdz šim neaprakstītas vielu kristāliskās formas. Novērtēta iegūto formu stabilitāte iegūšanas, ražošanas un uzglabāšanas apstākļos. Atsevišķām FAV veikta struktūras noteikšana, gan izmantojot pulvera rentgendifraktometriju, gan monokristālu rentgendifraktometriju. Iegūtie rezultāti ir aktuāli zāļu ražotājiem, kā arī tiem ir zinātniska nozīme no FAV īpašību apzināšanas un metožu attīstības viedokļa. Atslēgas vārdi: kristālsolvāti, vielas stāvokļa diagramma, nestehiometriskie solvāti, vielu termodinamiskā stabilitāte, fāžu p…

Dipeptidyl Enoates As Potent Rhodesain Inhibitors That Display a Dual Mode of Action

2015

Dipeptidyl enoates were prepared through a high-yielding two-step synthetic route. They have a dipeptidic structure with a 4-oxoenoate moiety as a warhead with multiple reactive sites. Dipeptidyl enoates were screened against rhodesain and human cathepsins B and L, and were found to be potent and selective inhibitors of rhodesain. Among them (S,E)-ethyl 5-((S)-2-{[(benzyloxy)carbonyl]amino}-3-phenylpropanamido)-7-methyl-4-oxooct-2-enoate (6) was the most potent, with an IC50 value of 16.4 nm and kinact/Ki=1.6×106 m−1 s−1 against rhodesain. These dipeptidyl enoates display a reversible mode of inhibition at very low concentrations and an irreversible mode at higher concentrations. Inhibition…

The effects of locomotor pattern diversity and ageing on the lower limb joint mechanics and loading during human walking and running

2015

Aportación de la monitorización farmacocinética de vancomicina a la calidad farmacoterapéutica y seguridad del paciente neonato prematuro

2014

Vancomicina es un antibiótico utilizado con gran frecuencia en pacientes neonatos prematuros ingresados en las Unidades de Cuidados Intensivos Neonatales. La elevada variabilidad en los parámetros farmacocinéticos en este grupo de población representa la mayor barrera en el desarrollo y en la optimización de regímenes de dosificación. Esta situación favorece el desarrollo de diversas recomendaciones basadas en modelos farmacocinéticos poblacionales y nomogramas de dosificación, que consideran, para el cálculo de la dosis, variables como la edad postconcepcional, postnatal, creatinina sérica o el peso de los pacientes. Sin embargo, la experiencia clínica ha puesto de relieve que las concentr…