Effect of Prestrain on Payne Effect and Hysteresis Loss of Carbon-Black-Filled Rubber Vulcanizates: Measurements and Modeling.

The performance of a viscoelastic damper is governed by the mechanical properties of the viscoelastic material, which are sensitive to prestrain. Among viscoelastic materials, carbon black (CB)-filled rubber vulcanizate is commonly used in structural applications. In this paper, the prestrain-dependent Payne effect and hysteresis loss of CB-filled rubber vulcanizates are investigated through experimental and theoretical analysis. Based on the experimental results, the classic quantitative models proposed by Kraus, Huber-Vilgis, and Maier-Göritz are used to describe the Payne effect. The results show that the Maier-Göritz model is most suitable to describe the Payne effect, especially for the loss modulus. After calculating the area of the hysteresis loops, hysteresis loss curves at various dynamic strain amplitudes are parallel to each other. Through application of the time-strain superposition principle, the hysteresis loss at any arbitrary prestrain can be predicted. Thus, the aim of this paper is to provide guidance for researchers in choosing an accurate model for future investigations of the prestrain-dependent Payne effect. An accelerated characterization method is useful for the prediction of the hysteresis loss of rubber products using small amounts of experimental data, which can provide manufacturers with more attractive and lower cost opportunities for testing the mechanical properties of rubber products.

A new direction in Chinese herbal medicine ameliorates for type 2 diabetes mellitus: Focus on the potential of mitochondrial respiratory chain complexes.

ETHNOPHARMACOLOGICAL RELEVANCE: Diabetes is a common chronic disease. Chinese herbal medicine (CHM) has a history of several thousand years in the treatment of diabetes, and active components with hypoglycemic effects extracted from various CHM, such as polysaccharides, flavonoids, terpenes, and steroidal saponins, have been widely used in the treatment of diabetes. AIM OF THE STUDY: Research exploring the potential of various CHM compounds to regulate the mitochondrial respiratory chain complex to improve type 2 diabetes mellitus (T2DM). MATERIALS AND METHODS: The literature data were primarily obtained from authoritative databases such as PubMed, CNKI, Wanfang, and others within the last decade. The main keywords used include "type 2 diabetes mellitus", "Chinese medicine", "Chinese herbal medicine", "mitochondrial respiratory chain complex", and "mitochondrial dysfunction". RESULTS: Chinese herbal medicine primarily regulates the activity of mitochondrial respiratory chain complexes in various tissues such as liver, adipose tissue, skeletal muscle, pancreatic islets, and small intestine. It improves cellular energy metabolism through hypoglycemic, antioxidant, anti-inflammatory and lipid-modulating effects. Different components of CHM can regulate the same mitochondrial respiratory chain complexes, while the same components of a particular CHM can regulate different complex activities. The active components of CHM target different mitochondrial respiratory chain complexes, regulate their aberrant changes and effectively improve T2DM and its complications. CONCLUSION: Chinese herbal medicine can modulate the function of mitochondrial respiratory chain complexes in various cell types and exert their hypoglycemic effects through various mechanisms. CHM has significant therapeutic potential in regulating mitochondrial respiratory chain complexes to improve T2DM, but further research is needed to explore the underlying mechanisms and conduct clinical trials to assess the safety and efficacy of these medications. This provides new perspectives and opportunities for personalized improvement and innovative developments in diabetes management.

Age differences in facial trustworthiness judgement based on multiple facial cues.

Multiple facial cues such as facial expression and face gender simultaneously influence facial trustworthiness judgement in adults. The current work was to examine the effect of multiple facial cues on trustworthiness judgement across age groups. Eight-, 10-year-olds, and adults detect trustworthiness from happy and neutral adult faces (female and male faces) in Experiment 1. Experiment 2 included both adult and child faces wearing happy, angry, and neutral expressions. Nine-, 11-, 13-year-olds, and adults had to rate facial trustworthiness with a 7-point Likert scale. The results of Experiments 1 and 2 revealed that facial expression and face gender independently affected facial trustworthiness judgement in children aged 10 and below but simultaneously affected judgement in children aged 11 and above, adolescents, and adults. There was no own-age bias in children and adults. The results showed that children younger than 10 could not process multiple facial cues in the same manner as in older children and adults when judging trustworthiness. The current findings provide evidence for the stable-feature account, but not for the own-age bias account or the expertise account.

A miniaturized sorbent phase-based extraction device in the form of syringe filter holder using molecularly imprinted polymer as sorbent and its application to extract benzophenones.

The molecularly imprinted polymer using 2,4-dihydroxybenzophenone as the template (DHBP-MIP) was synthesized via sacrificial support method. The DHBP-MIP was demonstrated to possess good adsorption capacity and selectivity towards benzophenones. Moreover, a miniaturized sorbent phase-based extraction device in the form of syringe filter holder using DHBP-MIP as the sorbent was proposed, and named as µ-SPE-SFH-MIP device. The µ-SPE-SFH-MIP device consisted of a reusable syringe filter holder, flexible amount of sorbent and a sub-microporous membrane, which could be conveniently connected to different driving forces, like syringe pump, solid-phase extraction device and peristaltic pump. It was successfully applied to extract five benzophenones from swimming pool water and human urine samples, combined with high performance liquid chromatograph-UV analysis, with detection limits of 0.12-0.68 µg L-1 and 0.21-1.05 µg L-1, respectively. The accuracy and precision of the analytes were in the range of 89.27%-113.35% for swimming pool water samples and 90.65%-108.00% for urine samples, with all the relative standard deviation values below 7.89%. The µ-SPE-SFH-MIP device was portable, cost-effective operational convenient and suitable for the small-size samples; moreover, with the MIP as the sorbent, it afforded additional high selectivity and sensitivity.

Simultaneous determination of nimesulide and its four possible metabolites in human plasma by LC-MS/MS and its application in a study of pharmacokinetics.

In this study, it was the first time that we simultaneously quantified nimesulide and its possible metabolites M1, M2, M3 and M4 by employing liquid chromatography-tandem mass spectrometry (LC-MS/MS). Nimesulide-d5 was used as internal standard (IS) for validation. Analytes and IS were recovered from human plasma by protein precipitation with acetonitrile. Prepared plasma samples were analyzed under the same LC-MS/MS conditions, and chromatographic separation was realized by using an Ultimate C18 column, with run time being 5min for each sample. Our results showed that various analytes within their concentration ranges could be quantified accurately by using the method. Mean intra- and inter-day accuracies ranged from -4.8% to 4.8% (RE), and intra- and inter-assay precision ≤6.2% (RSD). The following parameters were validated: specificity, recovery, matrix effects, dilution integrity, carry-over, sample stability under a variety of storage and handling conditions (room temperature, freezer, freeze-thaw and post-preparative) and stock solution stability. Pharmacokinetics of nimesulide and its metabolites were calculated based on the analysis of samples collected from twelve Chinese healthy volunteers after single oral dose of 100mg nimesulide tablets. By applying the pharmacokinetic determination into human samples, we preliminarily detected a new metabolite of nimesulide (M4*), and the concentration of M4* was relatively higher in plasma. Furthermore, we predicted part of conceivable metabolism pathway in plasma of after oral administration of 100mg nimesulide tablets. This research provided an experimental basis for further studies on metabolic activation and biotransformation of nimesulide, and for more comprehensive conjecture of its metabolic pathways.