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A simplified molecular imprinting strategy through electrospinning of polyacrylonitrile for thin film microextraction of selected pesticides
No full textMolecularly imprinted polymers (MIPs) have been extensively used as selective extractive phases for sample preparation because of their analyte-selective binding sites. However, MIP preparation requires optimized monomer-template interactions and long polymerization reactions. In this study, a novel and simple method of MIP preparation was proposed based on electrospinning. Instead of preparing analyte-monomer complexes before polymerization, model analytes (trifluralin and carbaryl) were directly dissolved in a polyacrylonitrile (PAN) solution, then electrospun into nanofibrous mats. This allowed for a means of preparation of highly crystalline, template-imprinted nanostructures with minimal synthetic complexity. Following the characterization studies for the new material, the extraction properties of the imprinted and nonimprinted electrospun mats were investigated in thin film microextraction (TFME) studies by extracting trifluralin and carbaryl from water samples, followed by gas chromatography-mass spectrometry (GC–MS) analysis. The optimization results showed that samplers containing 10.0 mg of MIP sorbents made by electrospinning of a solution containing 5.0 mg of template in 1.0 mL of PAN solution resulted in approximately 4 and 7 times enhanced extraction recoveries for carbaryl and trifluralin compared to samplers made of non-imprinted bulk PAN. Moreover, the cross-reactivity testing performed with non-template analytes (malathion and diazinon) suggested a more specific extraction towards trifluralin compared to carbaryl. The proposed new technique was also validated using computational methodology, which supported the experimental finding about higher selectivity towards trifluralin. This may signify a probability for structural orientation of partially charged trifluralin under an electrical field in electrospun PAN creating favorable extraction sites
The effect of stromal vascular fraction cells derived from epididymal and inguinal adipose tissues on in vitro spermatogenesis
No full textInfertility affects 10–20% of sexually active couples and male-related factors contribute to 30–50% of all cases of infertility. The development of three-dimensional in vitro approaches to promote the differentiation of spermatogonial stem cells (SSCs) into functional spermatozoa is an essential step for the treatment of male infertility. Stromal vascular fraction (SVF) cells derived from adipose tissue are known to have a regenerative effect on spermatogenesis and testicular regeneration after testicular damage. The study assessed the effect of SVF cells from epididymal and inguinal adipose tissue on in vitro spermatogenesis. Testicular cells from prepubertal mice were cultured alone as control and co-cultured with SVF cells from epididymal (ESVF) and inguinal (ISVF) adipose tissue in experimental groups by an air–liquid interface system. Spermatogenic progression was evaluated histomorphometrically and immunohistochemically at weeks 1, 3, 4, and 6. ESVF increased formation of tubule-like structures at week 1 and ISVF had a similar effect at week 4. The ISVF group showed higher numbers of ID4(+) (Inhibitor of DNA Binding 4) SSCs than control at all time points. At weeks 3 and 4, the ISVF exhibited increased number of SCP3(+) (Synaptonemal Complex Protein 3) spermatocytes compared to the control group and the ESVF showed a similar increase at week 6. The presence of ACR(+) (Acrosin) spermatids was observed in all groups at week 3. At week 4, the ISVF group had more ACR(+) spermatids than the control and ESVF groups. Our findings demonstrated that SVF cells effectively supported in vitro spermatogenesis. Notably, inguinal-derived SVF cells led to a higher production of ACR(+) spermatids than edidiymal-derived SVF cells. In conclusion, inguinal derived SVF cells can be used as a new co-culture method to preserve the SSC pool and promote in vitro spermatogenesis in infertile patients
Navigating digitalization and global value chains: Empirical insights from the Chinese manufacturing industry
No full textIn a rapidly digitalized and globalized world, enterprises understand how digitalization shapes the global value chain (GVC) to remain competitive. Previous studies have examined digitalization, trade openness, research and development (R&D) investment, foreign direct investment (FDI), and infrastructure quality, leaving a gap in understanding the integrated determinants of GVC. This study aims to fill this research gap by examining the integrated impact of digitalization on GVC. Unlike previous studies, this study develops a holistic framework that captures a multidimensional analysis of the interaction between digitalization and GVC participation. This study used panel data models to achieve the desired outcomes from China's manufacturing sector, and the results were obtained using Machine Learning Techniques. This study shows that manufacturing, domestic and foreign digitalization, research and development, productivity, and GVC participation all improve a GVC's position; however, foreign direct investment hampers this improvement. Trade openness, financial growth, and infrastructure all positively impact the relationship between digitalization and the GVC position. By explicitly integrating digital technologies with broader economic and institutional factors, these findings offer a comprehensive understanding of the drivers of GVC competitiveness and provide actionable insights for the manufacturing sectors of emerging economies undergoing rapid digital transformation
NMR Investigations of Honey: Chemical Composition, Chemical Physical Properties and Molecular Dynamics
No full textHoney is the best known and a widely used bee product, as well as one of the most defrauded foods. This paper focuses on the analysis of honey by different NMR techniques, complemented by some conventional methods to characterize food. Twenty-six honey samples of different botanical and geographical origins have been investigated. The chemical composition of honey samples in terms of water content and sugar concentrations was determined, and high-resolution 1H NMR spectroscopy was used to identify, and in some cases to quantify, some of the minor chemical compounds considered important to discriminate the botanical origin of honey. Finally, we developed a model for molecular dynamics in honey, which was tested to analyse the 1H NMR relaxation dispersions as studied by fast field-cycling NMR relaxometry. In conclusion, an array of NMR techniques, ranging from high to low resolution, was applied to a broad set of honey samples from diverse botanical and geographical origins. The outcomes provide a foundation for future research and potential applications in honey authentication and characterization
Building Raw Material Recovery Capabilities: The Case of Electric Batteries in the Automotive Industry
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Homological properties of persistent homology
No full textIn this paper, we investigate to what extent persistent homology benefits from the properties of a homology theory. We show that persistent homology benefits from a Mayer-Vietoris sequence and a long exact sequence for a pair if one works with graded persistence modules. We also give concrete examples showing that the same is not the case for persistent homology groups