Hydrothermal Synthesis of Hierarchical SnO2 Nanostructures for Improved Formaldehyde Gas Sensing

The indoor environment of buildings affects people’s daily life. Indoor harmful gases include volatile organic gas and greenhouse gas. Therefore, the detection of harmful gas by gas sensors is a key method for developing green buildings. The reasonable design of SnO2-sensing materials with excellent structures is an ideal choice for gas sensors. In this study, three types of hierarchical SnO2 microspheres assembled with one-dimensional nanorods, including urchin-like microspheres (SN-1), flower-like microspheres (SN-2), and hydrangea-like microspheres (SN-3), are prepared by a simple hydrothermal method and further applied as gas-sensing materials for an indoor formaldehyde (HCHO) gas-sensing test. The SN-1 sample-based gas sensor demonstrates improved HCHO gas-sensing performance, especially demonstrating greater sensor responses and faster response/recovery speeds than SN-2- and SN-3-based gas sensors. The improved HCHO gas-sensing properties could be mainly attributed to the structural difference of smaller nanorods. These results further indicate the uniqueness of the structure of the SN-1 sample and its suitability as HCHO- sensing material.

Photorheological fluids of azobenzene polymers for lubrication regulation

Fluid viscosity is ubiquitous property and is of practical importance in intelligent fluids, industrial lubrication, and pipeline fluid transportation. Recently, there has been a surging interest in viscosity regulation. Here, we have developed a group of photorheological fluids by utilizing azobenzene polymers with a light-induced microstructure transformation. In this work, a photosensitive polymer with 4,4′-bis-hydroxyazobenzene as the main chain was designed and synthesized as a pivotal functional material. The sufficiently large structural difference under ultraviolet and near-infrared light makes it possible to regulate the viscosity of a polyethylene glycol solution. The viscosity of the photosensitive rheological fluids under ultraviolet light radiation is found to be up to 45.1% higher than that under near-infrared light radiation. To explore this intelligent lubricating technology, the friction regulation of ceramic sliding bearings was investigated utilizing photosensitive rheological fluids. Reversible friction regulation with a ratio of up to 3.77 has been achieved by the alternative irradiation of near-infrared and ultraviolet light, which can be attributed to the differences in mechanical properties and molecular structures under ultraviolet and near-infrared light according to both simulations and experiments. Such photorheological fluids will have promising applications in controllable lubrication, intelligent rheological fluids, and photosensitive dampers.

Re-Contemplating the Classification of Multiple Reeds

The 2011 Revision of the Hornbostel-Sachs Classification of Musical Instruments by the MIMO Consortium categorises the “reedpipes with double (or quadruple) reeds” (422.1) according to the number of pipes, bore shapes, and finger holes, as it does to many other instrument groups. However, this scheme rather overlooks the significantly varied features of the multiple reeds themselves – their structural difference that determines their making and functioning, and how they connect to the pipe body – especially considering the vast varieties and distribution of multiple reeds compared with other types of reed pipes. Following the hierarchical classification of reed pipes (422) primarily according to the types of reeds, this paper would propose a further classification based on the “subtypes” of multiple reeds. The first level divides into “idioglot reeds” and “staple-mounted reeds” based on the connection of reeds with the pipe body. Idioglot reeds make one-part and two-part reed pipes, the former “usually a flattened stem” of the upper end of the pipe itself and the latter made from unbroken thick cane that fits inside the pipe bore. In contrast, staple-mounted reeds make three-part reed pipes. Some have fixed sides so that only the tips of reed blades are free to vibrate, while others have detached individual leaves that can vibrate on all sides. Given that reeds, as the primary source of sonic vibration, decide many fundamental features of a reed pipe, this recontemplated classification is likely to provide more distinct insight into their construct, functioning, and historical lineages.

Homo-composition and hetero-structure nanocomposite Pnma Bi2SeS2 - Pnnm Bi2SeS2 with high thermoelectric performance

Nanocomposite engineering decouples the transport of phonons and electrons. This usually involves the in-situ formation or ex-situ addition of nanoparticles to a material matrix with hetero-composition and hetero-structure (heC-heS) interfaces or hetero-composition and homo-structure (heC-hoS) interfaces. Herein, a quasi homo-composition and hetero-structure (hoC-heS) nanocomposite consisting of Pnma Bi2SeS2 - Pnnm Bi2SeS2 is obtained through a Br dopant-induced phase transition, providing a coherent interface between the Pnma matrix and Pnnm second phase due to the slight structural difference between the two phases. This hoC-heS nanocomposite demonstrates a significant reduction in lattice thermal conductivity (~0.40 W m−1 K−1) and an enhanced power factor (7.39 μW cm−1 K−2). Consequently, a record high figure-of-merit ZTmax = 1.12 (at 773 K) and a high average figure-of-merit ZTave = 0.72 (in the range of 323–773 K) are achieved. This work provides a general strategy for synergistically tuning electrical and thermal transport properties by designing hoC-heS nanocomposites through a dopant-induced phase transition.

Characterization of the gut microbiota in hemodialysis patients with sarcopenia

Purpose Maintenance hemodialysis (MHD) patients are at high risk of sarcopenia. Gut microbiota affects host metabolic and may act in the occurrence of sarcopenia importantly. This study aimed to study the characterization of the gut microbiota in MHD patients with sarcopenia, and to further reveal the complex pathophysiology of sarcopenia in MHD patients. Methods Fecal samples and clinical data were collected from 30 MHD patients with sarcopenia, and 30 age-and-sex-matched MHD patients without sarcopenia in 1 general hospital of Jiangsu Province from December 2020 to March 2021. 16S rRNA sequencing technology was used to analyze the genetic sequence of the gut microbiota for evaluation of the diversity, species composition, and differential microbiota of the two groups. Results Compared to MHD patients without sarcopenia, the ACE index of patients with sarcopenia was lower (P = 0.014), and there was a structural difference in the β-diversity between the two groups (P = 0.001). At the genus level, the relative abundance of Tyzzerella_4 in the sarcopenia group was significantly higher than in the non-sarcopenia group (P = 0.039), and the relative abundance of Megamonas (P = 0.004), Coprococcus_2 (P = 0.038), and uncultured_bacterium_f_Muribaculaceae (P = 0.040) decreased significantly. Conclusion The diversity and structure of the gut microbiota of MHD patients with sarcopenia were altered. The occurrence of sarcopenia in MHD patients may be influenced by gut microbiota.

HPLC Method for Separation of Cannabidiol Hemp Seed Oil with Skin Lipids and Tandem HRMS Technology for Characterization of a Chemical Marker

Cannabidiol (CBD) hemp seed oil is a commercial raw material with antioxidant and anti-inflammatory benefits that has been formulated into body wash and skin care products. The biggest analytical challenge is how to simultaneously quantify CBD and hemp seed oil as they deposited on the skin surface. CBD is easily separated and quantified from skin surface extracts via a HPLC-mass spectrometry methodology. However, the structural skeleton of triacylglycerides (TAGs) in hemp seed oil is same as those from the skin surface sebum. The strong hydrophobicity with subtle structural difference challenges their separation. In this project, a new reverse phase HPLC-high resolution mass spectrometry methodology was developed with a strong mobile phase normal propanol. The separated hemp seed oil TAGs in the chromatogram were identified and characterized using data-dependent acquisition (DDA) technology. Based on the daughter ion characterization, the separated peak with an ammonium adduct at 890.7226 [M + NH4]+ was confirmed as the parent ion of glycerol with three omega-3 fatty acid chains. This is the first time TAG structure with direct HPLC-tandem mass spectrometry technology has been elucidated without a hydrolysis reaction. The confirmed TAG structure with an ammonium adduct at 890.7226 ± 0.0020 can be used as a representative chemical marker for the hemp seed oil quantification.