Trinuclear and tetranuclear magnesium alkoxide clusters supported by bulky phenolates with triangular or rhombic structures were readily synthesized in acceptable yields via the reaction of ...2-N,N-dimethylaminoethanol/methoxyethanol, different phenols, and dibutylmagnesium. These complexes have been characterized using (1)H and (13)C NMR, elemental analyses, and X-ray crystallography. The experimental results indicate that these clusters are efficient and excellent initiators for the ring-opening polymerizations (ROPs) of l-lactide (LA) and afford polylactides with desired molecular weights and narrow polydispersity indexes (PDIs). Complex 2 can even catalyze the ROP of 4000 equiv of l-lactide in 1 min in a controlled model. Kinetic studies indicate that the polymerization is first-order for both the trinuclear magnesium complex 3 and LA. However, for the tetranuclear magnesium complex 5, the polymerization rate is first order for 5 and second order for LA.
Zirconium nitride (ZrN) is an important material for the mechanical industries due to its excellent properties such as excellent wear resistance, high hardness, etc. In practical applications, it is ...necessary to study how to regulate the mechanical properties of materials to meet the needs of different applications. To better understand the influence of vacancies and oxygen on the mechanical property of ZrN, we studied the tensile strength of the ZrN with oxygen atom doping and zirconium vacancy introduction by ab initio density functional theory. The mechanical property changes of modified ZrN in three crystallographic directions ( , , and ) were calculated. The results show that the tensile strength of ZrN can be increased by oxygen doping at a certain concentration, while that of ZrN can be decreased by the introduction of zirconium vacancy.
Titanium dioxide nanoparticles (TiO
2
NPs) are widely used in various disciplines, and it is imperative to evaluate their safety in the environment. In this paper,
Bombyx mori
(silkworm) was used as ...a model organism to evaluate the biological effects of different sized TiO
2
NPs, taking into consideration their effect on the larval growth, cocoon shell weight, tissues, and silk produced. The effect of the different sized TiO
2
NPs on the larval and cocoon shell weight was dose-dependent. The highest accumulation of titanium (Ti) following a modified TiO
2
NPs-treated mulberry diet was observed in the midgut. The expression of the light chain fibroin (FIBL) was three times higher in 0.33 g TiO
2
NPs-treated silk gland after 96 h. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analysis demonstrated that TiO
2
NPs-treated silk fiber (TiSF) exhibited a diminutive decrease in silk fiber (SF) crystallization and β-sheet compared to the control SF, respectively. The tensile tests of SF from silkworm fed with 0.03 g of 25 nm TiO
2
NPs were significantly improved when compared to the control SF. Significant changes in the surface morphology and thermal stability of SF were observed. The antimicrobial activity of TiSF was investigated against
Pseudomonas aeruginosa
and
Staphylococcus aureus
, with ciprofloxacin-treated SF acting as a control. It was documented that 0.09 g of 60 nm TiSF was most effective against
P. aeruginosa
at a zone of inhibition (ZOI) of 21.06 mm when compared with the control SF which recorded a ZOI of 17.19 mm. This study highlighted a different approach in evaluating the biological effects of TiO
2
NPs using the silkworm as a model and assessing their impact on the silk intrinsic property, which will be effective in biotechnology applications.
Syntheses of Thiophenes – Recent Advances Peng, Xue; Yin, Gaofeng; Wu, Kun ...
Asian journal of organic chemistry,
March 2024, 2024-03-00, 20240301, Letnik:
13, Številka:
3
Journal Article
Recenzirano
Thiophene, as an important sulfur‐containing heterocyclic, is widely used in pharmaceuticals, functional materials, and natural products. Furthermore, thiophene is of great interest to synthetic ...chemists due to its diverse reactivities. Over the past few decades, many synthetic strategies are developed for functionalized thiophenes. Several reviews have been reported. However, there is no review on thiophene synthesis summarized based on the sulfur sources. The current review envisioned to summary the synthesis methods for thiophene with the respect of sulfur sources and give support for choose the appropriate tools to obtain thiophene substrates.
This review provides an overview of the recent synthesis methods developed and made available for thiophene products preparation. Thiophene being an important sulfur‐containing heterocyclic motif finds use in pharmaceuticals, functional materials, organic chemistry and natural products, its efficient synthesis is equally important.
Triboelectric nanogenerator (TENG) has been seen as one of the most promising energy harvesting technologies. However, there are an irreconcilable contradiction between low friction and high ...electrical output performance of the TENG. Here, we have devised a macroscale liquid superlubric triboelectric nanogenerator based on solid-liquid-solid structure, leveraging the concept of liquid superlubricity technology, resulting in a remarkable increase in both the open circuit voltage and short-circuit current by 53.0 % and 58.4 %, respectively. This huge increase in electrical output performance is accompanied by a 99.1 % reduction in friction coefficient (≈ 0.0025) and 99.993 % reduction in wear rate (≈ 0.76×10−7 mm3/N·m), when compared to those of a lubricant-free triboelectric nanogenerator. This work delves into the lubrication and charge transfer mechanisms. The liquid superlubricity technology achieves friction reduction through a hybrid mechanism combining boundary and hydrodynamic lubrication. And the high outputs arise from the charges transfer at solid-liquid interface. The triboelectric charges generated by the friction pair are transferred from solid to the lubricating liquid. Meanwhile, the lubricating liquid promotes electron transfer and contributes additional electrons. Our work provides profound insights into the lubrication and charge transfer mechanisms at solid-liquid interfaces, and addresses the paradox of high output and low friction in TENGs.
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•Liquid superlubric TENG solves the contradiction between low friction and high electrical output performance.•This work provides profound insights into the liquid superlubricity and charge transfer at solid-liquid interface.•The liquid superlubric TENG shows an ultralow friction coefficient (≈0.0025) and wear rate (≈0.76×10−7 mm3/(N·m)).•The maximal Voc and Isc increase by 53.0 % and 58.4 %, respectively, accompanied by a 99.1 % reduction in friction coefficient.
To figure out the energy attenuation of micro/nanofibers (MNFs) more flexibly and conveniently, a backpropagation neural network (BPNN) is proposed to forecast the output intensity of rhodamine B ...(RhB) doped polymer microfibers (PMFs). According to the diameter, doping concentration, and propagation distance ( L ), we realize the L -dependence of output energy predictions for the excitation light ( I E ) and fluorescence ( I F ) of the doped PMFs. Hundreds of propagation distance-intensity data pairs acquired from dozens of RhB doped PMFs are used for the BPNN training. The prediction ability of the model is evaluated by the root-mean-square error (RMSE), the mean absolute percentage error (MAPE), and R 2 . The output intensity prediction performance of BPNN is compared with the traditional exponential-fitting (EF) method. The prediction results indicate that the two-hidden-layer network with one and seventeen neurons respectively provides the best performance. After training, BPNN gives a good intensity prediction for both the I E (RMSE = 3.16×10 −2 , MAPE = 7.3%, and R 2 = 0.9802) and the I F (RMSE = 0.91×10 −2 , MAPE = 0.89%, and R 2 = 0.9696) from the output end of the PMF with different diameters and doping concentrations. The energy losses of the two kinds of light from different doped PMFs are also calculated based on the predicted values, which are similar to the ones obtained from the EF method. The approach based on the BPNN prediction for the energy attenuation of the PMFs shows superiority in flexibility and applicability toward the traditional methods, which could promote the optimal design of the MNF devices and the practical application.
The role of the bronchoalveolar lavage fluid (BALF) microbiome in acute exacerbations of chronic obstructive pulmonary disease (AECOPD) remains unclear. The advent of the metagenomic next-generation ...sequencing (mNGS) has made it possible to reveal the complex microbiome composition of the respiratory tract. This study aimed to explore whether there are differences in the BALF microbiome of AECOPD patients with different lung functions. We enrolled 55 AECOPD patients and divided them into a mild group (n = 31) and a severe group (n = 24) according to their lung function. We collected BALF and submitted it to mNGS and bioinformatics analysis. At the species level, mNGS identified 264 bacteria, 13 fungi and 12 viruses in the mild group, and 174 bacteria, 6 fungi and 6 viruses in the severe group. Mixed bacterial and viral infection occurred in both groups. At the genus level, Rothia and Veillonella were more abundant in the mild group, while Pseudomonas and Staphylococcus were more abundant in the severe group. At the species level, compared with the mild group, the relative abundance of Haemophilus influenzae and Pseudomonas aeruginosa was increased in the severe group. Besides, the BALF microbiome composition was similar between the two groups, and there was no significant difference in α and β diversity. Forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) (%) showed no significant correlation with the Shannon or Simpson index. The microbiome abundance was different between the mild and severe groups; however, microbiome diversity was similar between the two groups. Based on our findings, Haemophilus influenzae and Pseudomonas aeruginosa may be the pathogenic bacteria that cause the difference in lung function in patients with AECOPD.The role of the bronchoalveolar lavage fluid (BALF) microbiome in acute exacerbations of chronic obstructive pulmonary disease (AECOPD) remains unclear. The advent of the metagenomic next-generation sequencing (mNGS) has made it possible to reveal the complex microbiome composition of the respiratory tract. This study aimed to explore whether there are differences in the BALF microbiome of AECOPD patients with different lung functions. We enrolled 55 AECOPD patients and divided them into a mild group (n = 31) and a severe group (n = 24) according to their lung function. We collected BALF and submitted it to mNGS and bioinformatics analysis. At the species level, mNGS identified 264 bacteria, 13 fungi and 12 viruses in the mild group, and 174 bacteria, 6 fungi and 6 viruses in the severe group. Mixed bacterial and viral infection occurred in both groups. At the genus level, Rothia and Veillonella were more abundant in the mild group, while Pseudomonas and Staphylococcus were more abundant in the severe group. At the species level, compared with the mild group, the relative abundance of Haemophilus influenzae and Pseudomonas aeruginosa was increased in the severe group. Besides, the BALF microbiome composition was similar between the two groups, and there was no significant difference in α and β diversity. Forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) (%) showed no significant correlation with the Shannon or Simpson index. The microbiome abundance was different between the mild and severe groups; however, microbiome diversity was similar between the two groups. Based on our findings, Haemophilus influenzae and Pseudomonas aeruginosa may be the pathogenic bacteria that cause the difference in lung function in patients with AECOPD.
The SiO2 coating layer could effectively reduce the electrochemical polarization of Li4Ti5O12 and enhance electrochemical reaction kinetics of Li+ insertion/deinsertion. As a result, the Li4Ti5O12 ...modified with 2.5mol% SiO2 exhibits higher specific capacity and better rate capability. Moreover, the SiO2 coating layer is likely to cover the catalytic sites on the Li4Ti5O12 surface for the decomposition of electrolyte, thereby restraining the formation of SEI, which is favorable to improving the cycling stability of Li4Ti5O12. Display omitted
•The SiO2 modification method is easy to carry out.•The SiO2 coating layer could enhance the Li+ diffusion.•The SiO2 coating layer could suppress the formation of SEI.•The LTO modified with 2.5mol% SiO2 exhibits the best electrochemical performance.
The commercial Li4Ti5O12 is modified with SiO2 directly via a simple sol–gel method. The SiO2 modified Li4Ti5O12 samples are characterized by a variety of means such as powder X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) mapping, transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), galvanostatic charge–discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Compared with pure Li4Ti5O12, the structure of SiO2 modified Li4Ti5O12 has no change, and there is a SiO2 coating layer over the Li4Ti5O12 particles. Appropriate amount of SiO2 could effectively reduce the electrochemical polarization of Li4Ti5O12 and enhance electrochemical reaction kinetics of Li+ insertion/deinsertion. As a result, the Li4Ti5O12 modified with 2.5mol% SiO2 exhibits higher specific capacity and better rate capability. Moreover, the SiO2 coating layer is likely to cover the catalytic sites on the Li4Ti5O12 surface for the decomposition of electrolyte, thereby restraining the formation of solid electrolyte interphase (SEI), which is very favorable for improving the cycle performance of Li4Ti5O12. The SiO2 modification process is easy to control and carry out for industrialization, which could improve the electrochemical performance of Li4Ti5O12.
Epidemiological evidence indicates that anthocyanin consumption reduces the incidence of chronic and degenerative diseases. Therefore, the present study aimed to determine whether black rice ...anthocyanin (BRA), black soybean anthocyanin (BSA), and purple corn anthocyanin (PCA) could mitigate oxidative stress and inflammation associated obesity in C57BL/6 mice fed with a high-fat diet. BRA, BSA, or PCA was administered at doses of 200 mg kg
throughout the 12-week experiment and reduced the bodyweight by 9.6%, 13.3%, or 16.6%, respectively. Furthermore, BRA, BSA or PCA administration could effectively increase fecal butyric acid levels, elevate hepatic SOD and GPx activities, decrease lipid peroxidation, and downregulate the gene expression levels of TNFα, IL-6, iNOS, and NF-κB. Hence, BRA, BSA, or PCA might ameliorate diet-induced obesity by alleviating both oxidative stress and inflammation.
Direct carbon solid oxide fuel cells (DC-SOFCs) are high-efficiency and clean power generation systems that can directly utilize solid carbon to produce electricity. However, the cell performance is ...hampered by the sluggish kinetics of the reverse Boudouard reaction at operating temperatures, as dictated by their operational principle. Here, carbon fuels loaded with varying amounts of MgO catalyst were successfully developed to promote the reverse Boudouard reaction and DC-SOFC performance. At 850 °C, the DC-SOFC powered by 5 wt% Mg-loaded activated carbon achieved peak power output of 236 mW cm−2, demonstrating a notable enhancement of 41.3% compared to that of 165 mW cm−2 in pure activated carbon-fueled cell. Furthermore, the single cell discharged stably for a prolonged duration of 41.6 h under 50 mA, achieving a noteworthy fuel utilization of 33.3% at 850 °C. These underscored the substantial contribution of MgO to the enhancement of DC-SOFC performance and efficiency. More importantly, the MgO catalyst displayed excellent stability without agglomeration during the high-temperature operation of the cell. Density functional theory simulation confirmed experimental findings that MgO reduced the energy barrier of carbon gasification reaction, thereby providing sufficient carbon oxide for cell operation. Finally, the reaction paths and internal mechanism of MgO-catalyzed carbon gasification were proposed to offer theoretical backing for the effective conversion of solid carbon fuel and improvement of cell performance. This study offers original perspectives on advancing carbon gasification reaction catalysts to facilitate the stable and highly efficient operation of DC-SOFCs, contributing to reduced carbon emissions and advancing sustainability.
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