Somatostatin inhibits insulin release via SSTR2 in the hamster pancreatic islets

It is generally accepted that somatostatin receptor subtype 5 (SSTR5) mediates the inhibition of insulin release. This is due to the fact that in the human, rat, and mouse somatostatin (SST) inhibits insulin release via SSTR5; however, in a preliminary study from Dr. Hsu\u27s laboratory with HIT-T15 [beta]-cells that are derived from hamster insulinoma, it was found that a SSTR2 agonist, but not other SSTR agonists, inhibited insulin release. Since SSTR2 is highly expressed in tumor cells, it is possible that the results from HIT-T15 cells may be due to the nature of tumor cells. Thus, it is hypothesized that in hamsters, SSTR2 mediates somatostatin-induced inhibition of insulin release. Isolated hamster pancreatic islets were used in the present study to test this hypothesis. Both somatostatin (1-100 nM) and nonpeptide SSTR2 agonist L-779,976 (0.1-100 nM) inhibited insulin release in a dose-dependent manner. Nonpeptide agonists for SSTR1, 3, 4, and 5 at the highest concentration studied (1[mu]M) failed to inhibit insulin release. PRL-2903, a peptide SSTR2 antagonist (0.3-1[mu]M), antagonized somatostatin-induced inhibition of insulin release in a dose-dependent manner. It is concluded that in hamster [beta]-cells, somatostatin inhibits insulin release via SSTR2 but not SSTR5

An experimental study: An integrative strategy of PBL combined with an organ-systems-based curriculum to improve academic achievement and career maturity

This study aims to investigate the impact of integrating Problem-Based Learning (PBL) and Organ System-Based Curriculum (OSBC) on medical students' academic achievement and career maturity within the context of medical education. An experimental design was employed, involving students from a medical school in China. Participants were randomly assigned to either a control group with a traditional curriculum or an experimental group receiving an integrated PBL and OSBC curriculum focused on cardiovascular system diseases. The intervention spanned four weeks. The results indicate that the experimental group demonstrated significantly higher academic achievement immediately after the intervention compared to the control group. This improvement persisted in a follow-up test conducted one month later. Career maturity also improved in the experimental group, albeit with a less sustained effect. The study underscores the potential of integrated teaching strategies in medical education for enhancing critical thinking and practical skills. However, long-term improvements in career maturity may necessitate further refinement of teaching methods. These findings contribute to the ongoing discourse on effective medical education strategies and emphasize the importance of a comprehensive approach to prepare students for academic excellence and clinical competence. Future research with larger sample sizes and consideration of additional influencing factors is recommended to gain deeper insights into the dynamics of medical education

Recrystallized parylene as a mask for silicon chemical etching

This paper presents the first use of recrystallized parylene as masking material for silicon chemical etch. Recrystallized parylene was obtained by melting parylene C at 350°C for 2 hours. The masking ability of recrystallized parylene was tested in HNA (hydrofluoric acid, nitric acid and acetic acid) solution of various ratios, KOH (potassium hydroxide) solution and TMAH (tetramethylammonium hydroxide) at different temperatures and concentrations. It is found that interface between parylene and the substrate can be attacked, which results in undercuts. Otherwise, recrystallized parylene exhibited good adhesion to silicon, complete protection of unexposed silicon and silicon etching rates comparable to literature data

Liquid Density Sensing Using Resonant Flexural Plate Wave Device with Sol-Gel PZT Thin Films

This paper presents the design, fabrication and preliminary experimental results of a flexure plate wave (FPW) resonator using sol-gel derived lead zirconate titanates (PZT) thin films. The resonator adopts a two-port structure with reflecting grates on the composite membrane of PZT and SiNx. The design of the reflecting grate is derived from a SAW resonator model using COM theory to produce a sharp resonant peak. The comparison between the mass and the viscosity effects from the theoretical expression illustrates the applications and the constraints of the proposed device in liquid sensing. Multiple coatings of sol-gel derived PZT films are adopted because of the cost advantage and the high electromechanical coupling effect over other piezoelectric films. The fabrication issues of the proposed material structure are addressed. Theoretical estimations of the mass and the viscosity effects are compared with the experimental results. The resonant frequency has a good linear correlation with the density of low viscosity liquids, which demonstrate the feasibility of the proposed device.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

Q-enhanced fold-and-bond MEMS inductors

This work presents a novel coil fabrication technology to enhance quality factor (Q factor) of microfabricated inductors for implanted medical wireless sensing and data/power transfer applications. Using parylene as a flexible thin-film device substrate, a post-microfabrication substrate folding-and-bonding method is developed to effectively increase the metal thickness of the surface-micromachined inductors, resulting in their lower self-resistance so their higher quality factor. One-fold-and-bond coils are successfully demonstrated as an example to verify the feasibility of the fabrication technology with measurement results in good agreements with device simulation. Depending on target specifications, multiple substrate folding-and-bonding can be extensively implemented to facilitate further improved electrical characteristics of the coils from single fabrication batch. Such Q-enhanced inductors can be broadly utilized with great potentials in flexible integrated wireless devices/systems for intraocular prostheses and other biomedical implants