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1.
A novel methodology for the solvent free auto-oxidation of methylbenzenes under mild conditions is disclosed. The new scheme is based on a combination of metallic salt (cobalt chloride) and a quaternary ammonium phase transfer catalyst (didecyldimethylammonium bromide) which together form a complex soluble catalyst in the organic phase. Major reaction parameters are studied and optimized and the procedure is applied for the conversion of several substituted toluenes to the corresponding benzoic acids in excellent isolated yields.  相似文献   
2.
Magnetic semiconductors are highly sought in spintronics, which allow not only the control of charge carriers like in traditional electronics, but also the control of spin states. However, almost all known magnetic semiconductors are featured with bandgaps larger than 1 eV, which limits their applications in long‐wavelength regimes. In this work, the discovery of orthorhombic‐structured Ti2O3 films is reported as a unique narrow‐bandgap (≈0.1 eV) ferromagnetic oxide semiconductor. In contrast, the well‐known corundum‐structured Ti2O3 polymorph has an antiferromagnetic ground state. This comprehensive study on epitaxial Ti2O3 thin films reveals strong correlations between structure, electrical, and magnetic properties. The new orthorhombic Ti2O3 polymorph is found to be n‐type with a very high electron concentration, while the bulk‐type trigonal‐structured Ti2O3 is p‐type. More interestingly, in contrast to the antiferromagnetic ground state of trigonal bulk Ti2O3, unexpected ferromagnetism with a transition temperature well above room temperature is observed in the orthorhombic Ti2O3, which is confirmed by X‐ray magnetic circular dichroism measurements. Using first‐principles calculations, the ferromagnetism is attributed to a particular type of oxygen vacancies in the orthorhombic Ti2O3. The room‐temperature ferromagnetism observed in orthorhombic‐structured Ti2O3, demonstrates a new route toward controlling magnetism in epitaxial oxide films through selective stabilization of polymorph phases.  相似文献   
3.
Coronavirus disease (COVID-19) is a contagious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This case report presents a patient who had difficulty eradicating the corona virus due to being treated with Rituximab, which depletes B lymphocyte cells and therefore disables the production of neutralizing antibodies. The combined use of external anti-viral agents like convalescent plasma, IVIG and Remdesivir successfully helped the patient’s immune system to eradicate the virus without B-cell population recovery. In vitro studies showed that convalescent plasma is the main agent that helped in eradicating the virus.  相似文献   
4.
Slot-die (SD) coating is used to fabricate fully solution processed organic solar cells (OSCs) based on a blend of high performance donor polymer (PTB7-Th) and a non-fullerene acceptor (IEICO-4F) for stable devices over extended periods of operation. The optimization of a sequential deposition process of transport and active layers, under ambient conditions, enable high efficiency slot-die coated solar cells with remarkable power conversion efficiencies (PCE) > 11.0% to bridge the gap between lab-to-fab. Fully slot-die coated inverted OSCs are demonstrated with efficiencies reaching 11% along with 1 cm2 devices, proving the scalability and reproducibility of the proposed technique. Further, replacing the evaporated Ag electrode with solution processed Ag nanowire (AgNW) electrodes shows the highest light utilization efficiency of 5.26% for semi-transparent OSC with a PCE of 9.07% and average visible transmission of 58%.  相似文献   
5.
The ‘Ulam’, a traditional Malay dish, are plants that can be eaten raw, as a form of local salad. The shoots and young leaves of Melicope ptelefolia are among the popular species, believed to be high in nutritional and medicinal values. The metabolomic fingerprinting analysis of the ethanolic extracts of leaves of M. ptelefolia was carried out using 1H Nuclear Magnetic Resonance (NMR) spectroscopy and multivariate data analysis in order to differentiate young and mature leaves and to evaluate the variation of their chemical composition. Principle component analysis (PCA) of the 1H NMR spectra showed a clear discrimination between the young and mature leaves extracts by PC3 and PC4. The compounds responsible for the differentiation were identified by comparison of 1H NMR chemical shifts and qualitative HPLC. The young leaves were found to be richer in fatty acids and the levels of the three marker compounds, p-O-geranylcoumaric acid, 2,4,6-trihydroxy-3-geranylacetophenone and 2,4,6-trihydroxy-3-prenylacetophenone, were clearly higher. The mature leaves contain higher levels of sugars and glycosidic components.  相似文献   
6.
7.
The quantity of hematopoietic progenitors in an apheresis collection is defined by the number of CD34(+) cells or granulocyte macrophage colony-forming units present. These parameters are believed to give roughly equivalent information on graft quality. We here report that the in vitro proliferative potential of r-metHuSCF (stem cell factor) plus filgrastim (granulocyte colony-stimulating factor; r-metHuG-CSF) mobilized peripheral blood (PB) CD34(+) cells obtained from previously heavily treated non-Hodgkin's lymphoma patients inversely correlates with extent of prior therapy. CD34(+) cells were enriched using the CellPro Ceprate system and placed in liquid culture for 4 weeks in the presence of either r-metHuSCF, IL-3, IL-6, filgrastim (S36G), or S36G plus erythropoietin (S36GE) with a weekly exchange of media and cytokines with reestablishment of culture at the starting cell concentration (Delta assay) and enumeration of progenitors. Starting with 4 x 10(4) CD34(+) cells from apheresis samples from patients who had received <10 cycles of prior chemotherapy, progenitors were detectable in culture at 4 weeks 81% of the time as compared to 14% with CD34(+) cells from patients who had received >10 cycles and 5% for >10 cycles plus radiotherapy. The total number of progenitors generated over the duration of culture (area under the curve) was calculated using the trapezoidal rule as a novel measure of the proliferative potential of the enriched PB CD34(+) cell population. The median area under the curve of CD34(+) cells from patients receiving <10 cycles of prior chemotherapy was 7.4 and 5.7 (x10(5)) using S36G or S36GE, respectively, 1.8 and 1.9 if the patients received >10 cycles of prior chemotherapy, and 1.4 and 1.2 if the patients received >10 cycles of prior chemotherapy plus radiotherapy (P < 0.001). These data show that prior therapy impacts on the quality of PB CD34(+) cells as measured by their ability to generate committed progenitors over a number of weeks in liquid culture.  相似文献   
8.
Wehbe N  Houssiau L 《Analytical chemistry》2010,82(24):10052-10059
This work reports a comparative study on the capability of low energy primary ion beams for depth profiling nonpolymeric molecules including amino-acid and sugar layers. Due to their different behavior regarding depth profiling, phenylalanine and trehalose molecules are chosen as reference systems. Each molecule was dissolved in suitable solvent prior to spin-coating on clean silicon wafer. The film thicknesses were in the order of 70 and 100 nm for phenylalanine and trehalose respectively. Depth profiling feasibility were assessed first using Cs(+) as reactive sputtering ion at various energies. The results obtained under Cs(+) sputtering ions are compared afterward to those obtained under Xe(+) sputtering ions which are inert and have a mass very similar to Cs(+). In order to investigate the effect of oxygen, depth profiling are also performed using either Xe(+) under oxygen flooding or O(2)(+) as sputtering ions. While phenylalanine could be depth profiled successfully using Cs(+) ions, Xe(+) and O(2)(+) ions failed to retain any characteristic signal. The sputtering yields measured as a function of the ion beam energies were higher using Cs(+), in particular at low energies. The chemical reactivity of the cesium atoms being implanted during the sputtering process helps to prevent the loss of the molecular phenylalanine signal. In contrast, depth profiling of trehalose was more successful upon Xe(+) and O(2)(+) compared to Cs(+). In this case the sputtering yields were higher if Xe(+) primary ion is employed instead of Cs(+). The different trends observed in this study are interpreted using arguments involving the reactivity of the sputtering ions.  相似文献   
9.
Friction stir welding (FSW) provides many advantages over traditional joining techniques, the most significant of which is lower cost of fabrication. Titanium alloys provide a high specific strength and increased corrosion resistance, which makes them an attractive material for use in extreme environments, such as those experienced by the next generation vehicle systems – marine, air, land or space. This research is focused on understanding the local mechanical properties and microstructure of a friction stir weld of a 12.7 mm thick plate of Ti-5111 in the direction transverse to the weld. The weld showed significant increases in strength and ductility in the stir zone. The retreating side of the weld showed reduced strength and ductility below the base property. This result, however, was found to be limited to the microscale. The understanding gained from this research should lead to future process optimizations of FSW.  相似文献   
10.
L-alpha glycerylphosphorylcholine (GPC), a nutritional supplement, has been demonstrated to improve neurological function. However, a new study suggests that GPC supplementation increases incident stroke risk thus its potential adverse effects warrant further investigation. Here we show that GPC promotes atherosclerosis in hyperlipidemic Apoe−/− mice. GPC can be metabolized to trimethylamine N-oxide, a pro-atherogenic agent, suggesting a potential molecular mechanism underlying the observed atherosclerosis progression. GPC supplementation shifted the gut microbial community structure, characterized by increased abundance of Parabacteroides, Ruminococcus, and Bacteroides and decreased abundance of Akkermansia, Lactobacillus, and Roseburia, as determined by 16S rRNA gene sequencing. These data are consistent with a reduction in fecal and cecal short chain fatty acids in GPC-fed mice. Additionally, we found that GPC supplementation led to an increased relative abundance of choline trimethylamine lyase (cutC)-encoding bacteria via qPCR. Interrogation of host inflammatory signaling showed that GPC supplementation increased expression of the proinflammatory effectors CXCL13 and TIMP-1 and activated NF-κB and MAPK signaling pathways in human coronary artery endothelial cells. Finally, targeted and untargeted metabolomic analysis of murine plasma revealed additional metabolites associated with GPC supplementation and atherosclerosis. In summary, our results show GPC promotes atherosclerosis through multiple mechanisms and that caution should be applied when using GPC as a nutritional supplement.  相似文献   
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