Safety Assessment of L-ß-Aminoisobutyric Acid (L-BAIBA): Subchronic Toxicity Study in Sprague Dawley Rats.

L-3-Aminoisobutyric acid (L-BAIBA) is an endogenous compound in human metabolism when thymine and valine undergo catabolism. L-BAIBA represents one of the two isomers of BAIBA in biological systems. BAIBA has been shown to reduce body fat percentage via an increase in fatty acid oxidation and a decrease in hepatic lipogenesis. However, no toxicological effects of L-BAIBA in animals or humans have been established. The present study was designed to evaluate the safety and toxic potentials of this compound, where L-BAIBA was administered orally to Sprague Dawley rats at 100, 300, and 900 mg/kg/day for 90 days. No treatment-related adverse effects were observed in any of the treatment groups. Based on the results, the No-Observed-Adverse-Effect Level (NOAEL) of L-BAIBA was 900 mg/kg/day.

Synthesis of Thin Bi9 O7.5 S6 Nanosheets for Improved Photodetection in a Wide Wavelength Range.

Bismuth-based compounds possess layered structures with a variety of stacking modes, endowing the compounds with diverse properties. As one type of bismuth oxysulfides, Bi9 O7.5 S6 nanocrystals has great applications in photodetection; however, the responsivity of bulky Bi9 O7.5 S6 is limited due to the poor charge separation. Herein, single-crystalline Bi9 O7.5 S6 thin nanosheets are successfully synthesized by using a solvothermal method. The thickness of the obtained Bi9 O7.5 S6 nanosheets is down to 15 nm and can be easily tuned by varying the reaction period. Moreover, the Bi9 O7.5 S6 nanosheets show strong light absorption in the visible and near infrared range, making it a promising candidate in optoelectronics. As a demonstration, the thin Bi9 O7.5 S6 nanosheets are used as active layer in an optoelectronic device, which exhibits sensitive photoelectric response to light in a wide range of 400-800 nm. The responsivity of the device reaches up to 1140 µA W-1 , and the performance of the device is stable after long-period illumination. This work demonstrates a great potential of the thin Bi9 O7.5 S6 nanosheets in optoelectronic devices, and these nanosheets may also be extended to various optoelectronic applications.

A flexible SERS-active film for studying the effect of non-metallic nanostructures on Raman enhancement.

Since the discovery of surface enhanced Raman scattering (SERS), the choice of SERS-active materials has been limited mainly to metals, especially gold and silver in the visible spectrum. Although non-metals can also be SERS-active by forming nanostructures or composite structures with SERS-active materials, the mechanism behind it is still unclear and there is no perfect technique to study it. In this work, by constructing a SERS structure on a flexible polydimethylsiloxane film, we provide a way to study the effect of non-metallic nanostructures on Raman enhancement by attaching the above film onto flat and nanostructured surfaces. It was found that a nanoporous silicon surface contributes to an additional, up to five times, Raman enhancement. The pore depth and pore size also influence the observed Raman enhancement. These findings will help us not only to understand the mechanism of SERS involving non-metallic nanostructures, but also to design more efficient SERS structures for various applications.