Perfluoroalkyl substances in food contact materials: preliminary investigation in Vietnam and global comparison.

Per- and polyfluoroalkyl substances (PFASs) are a group of concerned persistent toxic substances, especially for their application or unintentional formation in food contact materials (FCMs). However, information about the occurrence, sources, and fate of these pollutants in food packaging materials from Vietnam as well as Southeast Asian countries is probably still obscured. In this study, levels of 13 perfluoroalkyl carboxylic acids (PFCAs) and 4 sulfonates (PFSs) were determined in various types of food packaging samples collected from Vietnamese markets.

Highly stable, substrate-free, and flexible broadband halide perovskite paper photodetectors.

In this work, we aim to fabricate a highly stable and flexible perovskite paper photodetector based on a Zn-doped MAFAPbI perovskite and CNC. The paper photodetector has been successfully synthesized by the vacuum filtration method and deposited with interdigitated electrodes. The paper photodetector exhibits a significant photoresponse with a responsivity of 0.

Reconfigurable broadband metasurfaces with nearly perfect absorption and high efficiency polarization conversion in THz range.

Reconfigurable metasurfaces (RMSs) that enable the switching function of absorption and polarization conversion have attracted increasing attention. However, the design of RMSs to achieve wideband and high efficiency for both absorption and polarization conversion functions simultaneously remains a great challenge. Here, we propose the design of a RMS structure with a high-efficiency cross-polarization conversion and nearly perfect absorption.

Simple design of efficient broadband multifunctional polarization converter for X-band applications.

A simple design of a broadband multifunctional polarization converter using an anisotropic metasurface for X-band application is proposed. The proposed polarization converter consists of a periodic array of the two-corner-cut square patch resonators based on the FR-4 substrate that achieves both cross-polarization and linear-to-circular polarization conversions. The simulated results show that the polarization converter displays the linear cross-polarization conversion in the frequency range from 8 to 12 GHz with the polarization conversion efficiency above 90%.

Cost-effective capillary electrophoresis with contactless conductivity detection for quality control of beta-lactam antibiotics.

A simple and inexpensive approach for determination of various antimicrobial drugs using a purpose-made compact capillary electrophoresis (CE) instrument with capacitively coupled contactless conductivity detection (CD) is reported. The objective of the work is to propose an affordable and easily-implemented tool for quality control and detection of counterfeiting of antibiotic formulations in resource constrained developing countries. The design of the purpose-made CE-CD system was improved according to the feedback from over 10 years of use of our previous instrument.

Simple semi-automated portable capillary electrophoresis instrument with contactless conductivity detection for the determination of β-agonists in pharmaceutical and pig-feed samples.

An inexpensive, robust and easy to use portable capillary electrophoresis instrument with miniaturized high-voltage capacitively coupled contactless conductivity detection was developed. The system utilizes pneumatic operation to manipulate the solutions for all flushing steps. The different operations, i.