Structure based release kinetics analysis of doxazosin mesylate sustained-release tablets using micro-computed tomography.

The structures of solid dosage forms determine their release behaviors and are critical attributes for the design and evaluation of the solid dosage forms. Here, the 3D structures of doxazosin mesylate sustained-release tablets were parallelly assessed by micro-computed tomography (micro-CT). There were no significant differences observed in the release profiles between the RLD and the generic formulation in the conventional dissolution, but the generic preparation released slightly faster in media with ethanol during an alcohol-induced dose-dumping test.

Toxicology study of a tissue anchoring paclitaxel prodrug.

Background: Local drug presentation made possible by drug-eluting depots provides benefits for a vast array of diseases, including cancer, microbial infection, and wound healing. Drug-eluting depots provide sustained drug release of therapeutics directly at disease sites with tunable kinetics, remove the need for drugs to access disease sites from circulation, and reduce the side effects associated with systemic therapy. Recently, we introduced an entirely novel approach to local drug presentation named Tissue-Reactive Anchoring Pharmaceuticals (TRAPs).

Colloidal substrate-facilitated synthesis of gold nanohelices.

Helical nanostructures have unique optical and mechanical properties, yet their syntheses had always been quite challenging. Various symmetry-breaking mechanisms such as chiral templates, strain-restriction and asymmetric ligand-binding have been developed to induce the helical growth at nanoscale. In this work, with neither chiral ligands nor templates, gold (Au) nanohelices were synthesized via a facile wet-chemical method, through an asymmetric Active Surface Growth facilitated by colloidal silica nanoparticles (NPs).

Construction of spontaneous built-in electric field on heterointerface furnishing continuous efficient adsorption-directional migration-conversion of polysulfides.

Integrating sulfur with efficient electrocatalysts remains a pressing need in lithium-sulfur (Li-S) batteries for modulating the sluggish conversion kinetics and restricting the shuttle behavior of lithium polysulfides (LiPSs). Herein, a compact p-type FeO and n-type MoS heterostructure embedded on nitrogen-doped porous carbon (FeO-MoS-NPC-0.5) is meticulously constructed as dual-functional hosts that can facilitate continuous catalytic conversion of LiPSs.

Simultaneous Observation of the Anomerization and Reaction Rates of Enzymatic Dehydrogenation of Glucose-6-Phosphate by Dissolution DNP.

The hyperpolarization of biological samples using dissolution dynamic nuclear polarization (dDNP) has become an attractive method for the monitoring of fast chemical and enzymatic reactions using NMR by taking advantage of a large signal increase. This approach is actively developing but still needs key methodological breakthroughs to be used as an analytical method for the monitoring of complex networks of simultaneous metabolic pathways. In this article, we use the deceptively simple example of glucose-6-phosphate (G6P) oxidation reaction by the enzyme G6P dehydrogenase (G6PDH) to discuss some important methodological aspects of dDNP kinetic experiments, such as its robustness and its ability to provide repeatable results as well as the capacity of this time-resolved methodology to test kinetic models and hypotheses and to provide reliable parameter estimates.

A hybrid tau-leap for simulating chemical kinetics with applications to parameter estimation.

We consider the problem of efficiently simulating stochastic models of chemical kinetics. The Gillespie stochastic simulation algorithm (SSA) is often used to simulate these models; however, in many scenarios of interest, the computational cost quickly becomes prohibitive. This is further exacerbated in the Bayesian inference context when estimating parameters of chemical models, as the intractability of the likelihood requires multiple simulations of the underlying system.

Use of Population-Based Compartmental Modeling and Retinol Isotope Dilution to Study Vitamin A Kinetics and Total Body Stores among Ghanaian Women of Reproductive Age.

Background: Limited data are available on vitamin A kinetics and total body stores (TBS) in women. Such information can be obtained using compartmental modeling and retinol isotope dilution (RID).

Objectives: Objectives were to apply population-based ("super-subject") modeling to determine retinol kinetics in nonpregnant Ghanaian women of reproductive age and to use RID to predict TBS in the group and its individuals.

Reconstructing the phase of vanadium oxides enables redox-catalysis manipulated reversible sulfur conversion for stable Zn-S batteries.

The naturally sluggish redox kinetics and limited utilization associated with the sulfur conversion in Zn/S electrochemistry hinder its real application. Herein, we report an phase reconstruction strategy that activates the catalytic activity of vanadium oxides for invoking redox-catalysis to manipulate reversible sulfur conversion. It was identified that the VO@C/S precursor derived from metal organic frameworks could be transformed into VO ·HO@C/S by a facile electrochemical induction process.

Guanidinium Substitution Improves Self-Healing and Photodamage Resilience of MAPbI.

Self-healing materials can become game changers for developing sustainable (opto)electronics. APbX halide (=X) perovskites, HaPs, have shown a remarkable ability to self-heal damage. While we demonstrated self-healing in pure HaP compounds, in single crystals, and in polycrystalline thin films (as used in most devices), HaP compositions with multiple A (and X) constituents are preferred for solar cells.

Deciphering the emission dynamics of colloidal PbS quantum dots: a spectroscopic exploration under diverse environmental and experimental conditions.

This study employs a combination of spectroscopic techniques, including absorption, photoluminescence (PL), time-resolved PL kinetics, and transient absorption measurements, to elucidate the dynamics of excited states of oleic acid (OA)-capped colloidal PbS quantum dots (QDs) in toluene with a mean size of approximately 3 nm. PL decay profiles were properly treated employing either fitting or fitting-free models to extract average decay lifetimes and lifetime distributions. Our findings highlight the profound impact of factors such as particle concentration, size, surface treatment, and the surrounding environment on the optical properties of PbS QDs.

A 'through-DNA' mechanism for co-regulation of metal uptake and efflux.

Transition metals like Zn are essential for all organisms including bacteria, but fluctuations of their concentrations in the cell can be lethal. Organisms have thus evolved complex mechanisms for cellular metal homeostasis. One mechanistic paradigm involves pairs of transcription regulators sensing intracellular metal concentrations to regulate metal uptake and efflux.

P-Doping Modulated RuIr Nanoparticles Anchored on Co/N/C Catalysts with Improved Alkaline Hydrogen Evolution Activity and Stability.

Achieving efficient and stable hydrogen evolution reactions in alkaline conditions is crucial for hydrogen production. In this study, a RuIr/CoNC-P catalyst featuring RuIr alloys alongside P-doping and CoNx sites is developed. RuIr alloying optimizes the electronic structure between Ru and Ir, promoting electron transfer from Ru to Ir.

The Importance of Catalytic Effects in Hot-Electron-Driven Chemical Reactions.

Hot electrons (HEs) represent out-of-equilibrium carriers that are capable of facilitating reactions which are inaccessible under conventional conditions. Despite the similarity of the HE process to catalysis, optimization strategies such as orbital alignment and adsorption kinetics have not received significant attention in enhancing the HE-driven reaction yield. Here, we investigate catalytic effects in HE-driven reactions using a compositional catalyst modification (CCM) approach.

Determination of melatonin by potentiometric stripping analysis using sensor based on boron-doped diamond electrodes.

A three-electrode screen-printed sensor with heavily doped microcrystalline boron-doped diamond electrodes grown by chemical vapor deposition on alumina substrates was used to determine the concentration of melatonin by constant current potentiometric stripping analysis. This paper provides a detailed examination of the irreversible oxidation behavior of melatonin by cyclic voltammetry at a boron-doped diamond electrode. The relationship between the current response and the square root of the scan rate confirmed a diffusion-controlled oxidation process.

Studies on inhibition of α-glucosidase using debittered formulation of Bacopa monnieri juice: Enzyme inhibition kinetics, interaction strategy, and molecular docking approach.

Bacopa monnieri juice (BMJ) is traditionally used, reported, and scientifically validated for memory enhancement. However, its efficacy against diabetes is less explored. The extreme bitterness of BMJ restricts its commercial applications.

Assessing the impact of pin-to-plate atmospheric cold plasma on activity, stability, kinetics, and conformation of α-amylase.

α-amylase is responsible for shortening the shelf life of food by degrading starch and glycogen into maltose, disaccharides, and oligosaccharides. This study focuses on the effect of atmospheric cold plasma on the activity, stability, enzyme kinetics, and structural change for its application in α-amylase modifications. A reduction in the residual activity from 96.

Mapping the FF domain folding pathway via structures of transiently populated folding intermediates.

Despite the tremendous accomplishments of AlpaFold2/3 in predicting biomolecular structure, the protein folding problem remains unsolved in the sense that accurate atomistic models of how protein molecules fold into their native conformations from an unfolded ensemble are still elusive. Here, using chemical exchange saturation transfer (CEST) NMR experiments and a comprehensive four-state kinetic model of the folding trajectory of a 71 residue four-helix bundle FF domain from human HYPA/FBP11 we present an atomic resolution structure of a transiently formed intermediate, I2, that along with the structure of a second intermediate, I1, provides a description of the FF domain folding trajectory. By recording CEST profiles as a function of urea concentration the extent of compaction along the folding pathway is evaluated.

Unlocking the Ultrafast Deposition Kinetics within Bi-Tailored Core-Shell Structured Carbon Nanofibers for Highly Efficient and Ultrastable Sodium Metal Batteries.

Sodium metal anodes (SMA), featuring high energy content, low electrochemical potential and easy availability, are a compelling option for sustainable energy storage. However, notorious sodium dendrite and unstable solid-electrolyte interface (SEI) have largely retarded their widespread implantation. Herein, porous amorphous carbon nanofiber embedded with Bi nanoparticles in nanopores (Bi@NC) was rationally designed as a 3D host for SMA.

Role of the Sn-TiO/Ti-SnO Heterojunction in Enhancing the Photocatalytic Oxidation of Arsenite (As) through the Promotion of Charge Carrier Lifetime.

This study proposes the heterojunction photocatalyst, Sn-doped TiO/Ti-doped SnO (herein named SnTiO), as a promising alternative to pure TiO. SnTiO demonstrates improved light harvesting efficiency over TiO by generating longer-lived electron-hole (e-h) pairs, while also displaying a smaller band gap compared to pure TiO. Consequently, we show that it is a promising candidate for the photocatalytic oxidation (PCO) of As to the less toxic and more readily removable form As.