Trenched microwave resonator integrated with porous PDMS for detection and classification of VOCs with enhanced performance.

Microwave resonators combined with polymer absorption layers are widely used in volatile organic compound (VOC) detection based on their variable resonant frequencies. However, the response time is limited due to the polymer's slow volumetric absorption of VOC molecules. By constructing a porous structure in Polydimethylsiloxane (PDMS), resulting in reduced the response time to as short as 71.1%. To mitigate the sensitivity decline caused by the porous PDMS, a trenched-substrate complementary split-ring resonator (CSRR) is proposed for enhancing the interaction between the electromagnetic fields (EMFs) and the porous PDMS with VOCs. The removal of the substrate beneath CSRR's sensing region enhances the effective EMF, increasing frequency and amplitude sensitivities up to 175.5% and 137.8%, respectively. Responses to four common VOCs by the sensor show a maximum sensitivity of 217 Hz/ppm and a minimum limit of detection of 295 ppm. Additionally, resonant parameters and extracted lumped parameters are utilized to establish two decision-tree-based VOC classification models, achieving high accuracies of 98.71% and 99.59%, respectively. And the latter one fully utilizing responses throughout the swept band, proves superior in identifying similar substances. This sensor technology helps promote the sensitive detection and accurate classification of diverse VOCs.

Hydrophobic MOF/PDMS-Based QCM Sensors for VOCs Identification and Quantitative Detection in High-Humidity Environments.

Metal-organic frameworks (MOFs) have great potential in quartz crystal microbalance (QCM) platforms for volatile organic compound (VOCs) detection and recognition due to their unique properties. However, the MOFs' hydrophilicity degrades performance in high-humidity environments, limiting reliable VOC sensing in complex environments. Herein, we propose a novel VOC virtual sensor array (VSA) using a single QCM sensor with an adsorption layer composed of MIL-101(Cr) MOF and polydimethylsiloxane (PDMS), realizing stable sensing and accurate identification for different VOCs under various relative humidity (RH) conditions. The hydrophobic PDMS layer improves the moisture resistance of the sensor to 4 and 14 times in terms of shifts in resonant frequency and scattering parameters, respectively. In addition, performance is maintained over 2 days of water treatment, demonstrating superior water resistance. The highest sensitivity of 2.68 mdB ppm-1 is achieved for isopropanol detection, with the lowest limit of detection of 20.06 ppm for acetone. Combining resonant signals and lumped parameters, the proposed VSA technique effectively discriminates four VOCs (ethanol, 2-propanol, acetone, and acetonitrile) with a high accuracy of 95.3% under both 60% and 90% RH backgrounds. The studies provide a promising solution for reliable low-concentration VOC detection using QCM sensors in high-humidity environments such as underground spaces.

Effect of care intervention based on susceptible pointers of care quality in patients with hepatic cerebropathy.

OBJECTIVE: To investigate the effect of care intervention based on susceptible pointers of care quality in patients with hepatic cerebropathy. METHODS: The clinical data of 106 patients with hepatic cerebropathy from January 2020 to June 2021 were retrospectively analyzed, and they were assigned to a study group (n=53) or a control group (n=53) in line with diverse care means. The control group received conventional care, and the study group received additional care intervention based on susceptible pointers of care quality. The liver function, blood ammonia, neural function, capacity of daily life, and quality of life were observed and contrasted in the two groups before and after the intervention. The implementation or occurrence of key indicators of care quality, the occurrence of adverse care events, and patient care satisfaction rate were documented in the two groups after intervention. RESULTS: After the intervention, the liver function, neural function, capacity of everyday activities, quality of life and the implementation or occurrence of key pointers of care quality in the study group were superior to those in the control group (P<0.05). The blood ammonia and the incidence of adverse events in the study group were lower than those of the control group (P<0.05), and the care satisfaction rate of patients in the study group was higher than that of the control group (P<0.05). CONCLUSION: Care intervention based on susceptible pointers of care quality can help patients with hepatic cerebropathy to enhance liver and neural function, decrease blood ammonia and have fewer adverse care events, and enhances quality of life, care quality, and care satisfaction of patients.

Simultaneous LC-MS/MS screening for multiple phenethylamine-type conventional drugs and new psychoactive substances in urine.

New psychoactive substances are being launched in the drug market at a rapidly growing pace. More than 950 new psychoactive substances have been reported to the United Nations Office on Drugs and Crime. The development of new psychoactive substance abuse has drawn risks on public health and safety. Phenethylamines, along with other stimulants, accounted for the majority of the new psychoactive substances being reported in the past decade. This study presents a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous screening of 74 conventional and artificial phenethylamines in urine samples. The chromatographic analysis was performed by a direct dilute-and-shoot procedure using a Phenomenex Kinetex® Phenyl-Hexyl column (10 cm × 2.1 mm i.d., 1.7 µm) and two mobile phases (A: 0.1% formic acid aqueous solution with 5 mM ammonium acetate, B: 0.1% formic acid methanolic solution). The mass fragments were collected under the multiple reaction monitoring mode. The linearity range located in 1.0-50.0 ng/mL for quantitative analysis. The limit of detection and lower limit of quantification for 74 phenethylamines were 0.5 ng/mL and 1.0 ng/mL, respectively. The method was validated and further applied to analyze authentic urine samples. Twenty samples were tested positive of seven phenethylamines from 67 samples, whereas the contents detected were 9.8 ng/mL to 147.1 µg/mL with dilution factors of 40 to 20,000 folds.

Characterization and discrimination of human colorectal cancer cells using terahertz spectroscopy.

Terahertz technology has been widely used in biomedical research. Herein, terahertz time-domain attenuated total reflection (THz TD-ATR) spectroscopy was employed to characterize and discriminate human cancer cell lines (DLD-1 and HT-29). Terahertz responses of the cell lines were measured and Savitzky-Golay algorithm was applied to smooth the spectra of refractive index, absorption coefficient and dielectric loss tangent in terahertz regime. Principal component analysis (PCA) was then adopted for feature extraction and cell characterization. Based on the processed data, cancer cell lines were discriminated by applying random forests (RF) method to analyze three characteristic parameters separately and the results from them were compared. Results indicate that absorption coefficient was the most sensitive parameter for cancer cell discrimination. Our study suggests great potential for human cancer cell recognition and provides experimental basis for liquid biopsy.

A LC-MS/MS method for determination of 73 synthetic cathinones and related metabolites in urine.

Synthetic cathinones, which are a group of ß-keto analogs of phenethylamine, have been reported as the most emerging new psychoactive substances in the past decade. The quantity and variety of synthetic cathinones have continued to increase, which poses considerable risks to public health and social security. In this study, an analytical method based on liquid chromatography-tandem mass spectrometry (LCMS/MS) was established for the simultaneous determination of 73 synthetic cathinones and related metabolites in urine. The chromatographic analysis was performed using a Kinetex® Biphenyl column (10 cm ×2.1 mm, 1.7 µm), applying a gradient mobile phase, comprising 0.1 % formic acid aqueous solution with 5 mM ammonium acetate and 0.1 % formic acid methanolic solution; the entire run time of the analysis was within 8 min. The multiple reaction monitoring (MRM) mode was employed to collect the monitoring and quantitative ion pairs. Intra-day/inter-day precision and accuracy were less than 10 % for all the studied analytes. The limits of detection and quantification for all the analytes were 0.1-0.5 ng/mL and 0.5-1.0 ng/mL, respectively. The matrix effect was satisfactory for all the analytes, with a deviation lower than 20 %. The present method was further applied to 67 authentic urine samples in which 13 different synthetic cathinones were detected from 32 positive samples. The abuse of poly-synthetic cathinones was examined that up to seven items was detected in one case from authentic samples in this study.

Particle depletion of diesel exhaust restores allergen-induced lung-protective surfactant protein D in human lungs.

RATIONALE: Exposure to air pollution is linked with increased asthma morbidity and mortality. To understand pathological processes linking air pollution and allergen exposures to asthma pathophysiology, we investigated the effect of coexposure to diesel exhaust (DE) and aeroallergen on immune regulatory proteins in human airways. METHODS: Fourteen allergen-sensitised participants completed this randomised, double-blinded, cross-over, controlled exposure study. Each participant underwent four exposures (allergen-alone exposure, DE and allergen coexposure, particle-depleted DE (PDDE) and allergen coexposure, and sham exposure) on different order-randomised dates, each separated by a 4-week washout. Serum and bronchoalveolar lavage (BAL) were assayed for pattern recognition molecules, cytokines, chemokines and inflammatory mediators. RESULTS: In human airways, allergen-alone exposure led to accumulation of surfactant protein D (SPD; p=0.02). Coexposure to allergen and DE did not elicit the same increase of SPD as did allergen alone; diesel particulate reduction restored allergen-induced SPD accumulation. Soluble receptor for advanced glycation end products was higher with particle reduction than without it. In the systemic circulation, there was a transient increase in SPD and club cell protein 16 (CC16) 4 hours after allergen alone. CC16 was augmented by PDDE, but not DE. % eosinophils in BAL (p<0.005), eotaxin-3 (p<0.0001), interleukin 5 (IL-5; p<0.0001) and thymus and activation regulated chemokine (p=0.0001) were each increased in BAL by allergen. IL-5, SPD and % eosinophils in BAL were correlated with decreased FEV1. CONCLUSION: Short-term coexposure to aeroallergen and DE alters immune regulatory proteins in lungs; surfactant levels are dependent on particle depletion. TRIAL REGISTRATION NUMBER: NCT02017431.

A multi-analyte LC-MS/MS method for screening and quantification of nitrosamines in sartans.

An incident of sartan medicine contamination was notified by Europe in June 2018. The contaminant was identified as a probable carcinogenic nitrosamine and the recalls of sartan medicines were soon made. Since then, more nitrosamine contaminants in sartan medicines were reported. To broaden the applicability and variety in nitrosamine determination, a multi-analyte method is required. In this study, a feasible and sensitive multi-analyte LC-MS/MS method for determination of 12 nitrosamines in sartans was established, where the active pharmaceutical ingredients and final products merchandised in Taiwan were also examined. Chromatographic separation was achieved on an Xselect® HSS T3 column (15 cm × 3 mm i.d., 3.5 µm) with gradient elution using mobile phase A consisting of 0.1% formic acid in water and mobile phase B consisting of 0.1% formic acid in acetonitrile/methanol (2:8). Validation of the proposed method was also carried out. The limit of detection and limit of quantification for 12 nitrosamines were 20 ng/g and 50 ng/g, respectively. The intra-day and inter-day recoveries of nitrosamines were among 80-120% with precision of 20% for most nitrosamines within sartans matrices. The method was successfully established and applied to authentic samples which a total of 98 positive samples containing 5 distinct nitrosamines, including N-nitrosodiethylamine, N-nitrosodimethylamine, N-nitroso-N-methyl-4-aminobutyric acid, N-nitrosomorpholine and N-nitrosopiperidine, were detected from 557 authentic samples.

Analysis of Critical Dimensions for Nanowire Core-Multishell Heterostructures.

Critical dimensions for nanowire core-multishell heterostructures are analyzed by using finite-element method based on the energy equilibrium criteria. Results show that the nanowire core-shell heterostructure can sufficiently reduce the strain in the shell and increase the critical shell thickness. The critical dimensions for the nanowire core-multishell heterostructure are determined by the stress fields generated at two heterointerfaces. For thin barrier, the critical dimensions decrease as the core radius increases, while when the barrier is thick enough, the critical dimensions show an increase with the increase of core radius conversely. This can be attributed to a competition between the lattice mismatch and strain distribution, which dominate the critical dimensions alternatively. Two critical quantum well thicknesses are obtained in the nanowire core-multishell heterostructure. Below the dislocation-free critical thickness, the structure will be coherent regardless of the barrier thickness. While above the dislocation-unavoidable thickness, dislocations are always energetically favored. In the dislocation-controllable region between the two critical thicknesses, coherent structure can be obtained via controlling the well and barrier thicknesses. The results are in good agreement with the experimental data and may serve as guidance for the design of coherent nanowire core-multishell quantum well structures and devices.