SABRE hyperpolarization of nicotinamide derivatives and their molecular dynamics properties.

Signal amplification by reversible exchange hyperpolarization explores the chemical structure and kinetic properties of nicotinamide derivatives. N-Benzyl nicotinamide and nicotinic acid hydrazide compounds display relatively fast dissociation rates of approximately 7-8 s-1 and long proton T1 relaxation times of 5-20 s, respectively. Consequently, these substrates exhibit remarkable signal enhancements, reaching approximately 175 and 102 fold, respectively, underscoring the efficacy of the hyperpolarization technique in elucidating the behavior of these compounds.

Dynamic Nuclear Polarization of Selectively 29Si-Enriched Core@shell Silica Nanoparticles.

29Si silica nanoparticles (SiO2 NPs) are promising magnetic resonance imaging (MRI) probes that possess advantageous properties for in vivo applications, including suitable biocompatibility, tailorable properties, and high water dispersibility. Dynamic nuclear polarization (DNP) is used to enhance 29Si MR signals via enhanced nuclear spin alignment; to date, there has been limited success employing DNP for SiO2 NPs due to the lack of endogenous electronic defects that are required for the process. To create opportunities for SiO2-based 29Si MRI probes, we synthesized variously featured SiO2 NPs with selective 29Si isotope enrichment on homogeneous and core@shell structures (shell thickness: 10 nm, core size: 40 nm), and identified the critical factors for optimal DNP signal enhancement as well as the effective hyperpolarization depth when using an exogenous radical. Based on the synthetic design, this critical factor is the proportion of 29Si in the shell layer regardless of core enrichment. Furthermore, the effective depth of hyperpolarization is less than 10 nm between the surface and core, which demonstrates an approximately 40% elongated diffusion length for the shell-enriched NPs compared to the natural abundance NPs. This improved regulation of surface properties facilitates the development of isotopically enriched SiO2 NPs as hyperpolarized contrast agents for in vivo MRI.

Hyperpolarized 29Si magnetic resonance spectroscopy of selectively radical-embedded silica nanoparticles.

The embedding of radicals at different locations within core@shell silica nanoparticles contributes to enhanced polarization capability and can be self-polarized without adding external radicals. With grafting the radical source homogenously inside of the nanoparticles, a significant 29Si hyperpolarization signal enhancement of 49.4 was obtained.

Tailored synthesis of pH-responsive biodegradable microcapsules incorporating gelatin, alginate, and hyaluronic acid for effective-controlled release.

In response to escalating environmental concerns and the urgent need for sustainable drug delivery systems, this study introduces biodegradable pH-responsive microcapsules synthesized from a blend of gelatin, alginate, and hyaluronic acid. Employing the coacervation process, capsules were created with a spherical shape, multicore structure, and small sizes ranging from 10 to 20 µm, which exhibit outstanding vitamin E encapsulation efficiency. With substantial incorporation of hyaluronic acid, a pH-responsive component, the resulting microcapsules displayed noteworthy swelling behavior, facilitating proficient core ingredient release at pH 5.5 and 7.4. Notably, these capsules can effectively deliver active substances to the dermal layer under specific skin conditions, revealing promising applications in topical medications and cosmetics. Furthermore, the readily biodegradable nature of the designed capsules was demonstrated through Biochemical Oxygen Demand (BOD) testing, with over 80 % of microcapsules being degraded by microorganisms after one week of incubation. This research contributes to the development of responsive microcapsules and aligns with broader environmental initiatives, offering a promising pathway to mitigate the impact of microplastics while advancing various applications.

Accurate detection of enzymatic degradation processes of gelatin-alginate microcapsule by 1H NMR spectroscopy: Probing biodegradation mechanism and kinetics.

With an increase in the severity of environmental pollution caused by microbeads, the development of biodegradable microcapsules that can be applied in diverse fields has attracted significant attention. The degradation processes are directly related to biodegradable microcapsule creation with high stability and persistence. In this study, biodegradable microcapsules are synthesized via a complex coacervation approach using gelatin and alginate as the capsule main wall materials; additionally, enzyme-induced decomposition mechanisms are proposed by observing spectral changes in proton nuclear magnetic resonance (1H NMR) analyses. Additional analytical techniques confirm the chemical structure, morphology, and size distribution of the synthesized capsules; these uniform spherical microcapsules are 20-30 µm in size and possess a smooth surface. In addition to characterization, the microcapsules were exposed to targeted enzymes to investigate enzymatic effects using short-term and long-term degradation kinetics. Close inspection reveals that determination of the degradation rate constant of the major components in the capsule is feasible, and suggests two types of 4-stage degradation mechanisms that are enzyme-specific. These investigations demonstrate that capsule degradation can be explored in detail using 1H NMR spectroscopy to provide a viable strategy for monitoring degradation properties in the development of new biodegradable polymers.

Understanding family-based health insurance enrolment among informal sector workers in a rural district of Vietnam: Adverse selection and key determinants.

Background: Challenges remain in the implementation of family-based health insurance (FHI) - the key strategy for achieving universal health coverage in Vietnam. Objectives: To explore the experiences of and factors influencing enrolment in FHI among informal sector workers (ISW) in a rural district in Vietnam. Methods: A cross-sectional study was conducted from January to June 2016 in Tien Du, a rural district in Bac Ninh province. Secondary data were extracted from provincial social insurance databases to identify the rate of FHI among ISW in the district. Qualitative data were collected from 55 participants: 20 semi-structured in-depth interviews (IDI) and 6 focus group discussions (FGD). Data were transcribed verbatim. Thematic analysis was conducted. Results: Only 25.1% of ISW had FHI. Those individuals with FHI tended to be older or already experiencing health problems or have 'risky' jobs. The key determinants of adverse selection from different levels included: individual, family and health system. Conclusions: Low health insurance uptake remains an issue for ISW. Policy makers should consider raising awareness of FHI and improve the quality of primary health services, simplify the procedures of enrolment and claim for ISW. Additional government premium subsidy is required to increase FHI enrolment among ISW.