The functionalization of MoS2 is of paramount importance for tailoring its properties towards optoelectronic applications and unlocking its full potential. Zinc phthalocyanine (ZnPc) carrying an 1,2‐dithiolane oxide linker was used to functionalize MoS2 at defect sites located at the edges. The structure of ZnPc‐MoS2 was fully assessed by complementary spectroscopic, thermal, and microscopy imaging techniques. An energy‐level diagram visualizing different photochemical events in ZnPc‐MoS2 was established and revealed a bidirectional electron transfer leading to a charge separated state ZnPc. + ‐MoS2.?. Markedly, evidence of the charge transfer in the hybrid material was demonstrated using fluorescence spectroelectrochemistry. Systematic studies performed by femtosecond transient absorption revealed the involvement of excitons generated in MoS2 in promoting the charge transfer, while the transfer was also possible when ZnPc was excited, signifying their potential in light‐energy‐harvesting devices. 相似文献
The purpose of this study was to explore the possible link between metals and UV‐B‐induced damage in bacteria. The effect of growth in the presence of enhanced concentrations of different transition metals (Co, Cu, Fe, Mn and Zn) on the UV‐B sensitivity of a set of bacterial isolates was explored in terms of survival, activity and oxidative stress biomarkers (ROS generation, damage to DNA, lipid and proteins and activity of antioxidant enzymes). Metal amendment, particularly Fe, Cu and Mn, enhanced bacterial inactivation during irradiation by up to 35.8%. Amendment with Fe increased ROS generation during irradiation by 1.2–13.3%, DNA damage by 10.8–37.4% and lipid oxidative damage by 9.6–68.7%. Lipid damage during irradiation also increased after incubation with Cu and Co by up to 66.8% and 56.5% respectively. Mn amendment decreased protein carbonylation during irradiation by up to 44.2%. These results suggest a role of Fe, Co, Cu and Mn in UV‐B‐induced bacterial inactivation and the importance of metal homeostasis to limit the detrimental effects of ROS generated during irradiation. 相似文献
Treatment of 2-ketoglutaric acid with diazomethane gave 2-(metoxycarbonyl)-oxiranepropanoic acid methyl ester (2) wich lead to 2-hydroxy-2-methyl-glutaric acid dimethyl ester (3) by catalytic hydrogenation, wich was further processed to the title compound. 相似文献
The establishment of fragmentation pathways has a great interest in the identification of new or unknown related compounds present in complex samples. On that way, tentative fragmentation pathways for the ions generated by atmospheric pressure ionization of neutral per- and polyfluorinated alkyl substances (PFASs) have been proposed in this work. Electrospray (ESI), atmospheric pressure chemical ionization (APCI) and photoionization (APPI) were evaluated using mobile phases and source conditions that enhance the ionization efficiency of ions generated. A hybrid mass spectrometer consisting of a linear ion trap and an Orbitrap was used to combine the information of both multiple-stage mass spectrometry (MSn) and mass accuracy measurements to characterize and establish the genealogical relationship between the product ions observed. The ionization mechanisms to generate ions such as [M–H]−, [M]−•, and [M+O2]−• or the in-source collision-induced dissociation (CID) fragment ions in each API source are discussed in this study. In general, fluorotelomer olefins (FTOs) ionized in negative-ion APCI and APPI generated the molecular ion, while fluorotelomer alcohols (FTOHs) also provided the deprotonated molecule. Besides, fluorooctane sulfonamides (FOSAs) and sulfonamido-ethanols (FOSEs) led to the deprotonated molecule and in-source CID fragment ions, respectively. The fragmentation pathways from these precursor ions mainly involved initial α,β-eliminations of HF units and successive losses of CF2 units coming from the perfluorinated alkyl chain. Moreover, FTOHs and FOSEs showed a high tendency to generate adduct ions under negative-ion ESI and APPI conditions. The fragmentation study of these adduct ions has demonstrated a strong interaction with the attached moiety.
Banana, an important component in the diet of the global population, is one of the most consumed fruits in the world. This fruit is also very favorable to industry processes (e.g., fermented beverages) due to its rich content on soluble solids and minerals, with low acidity. The main objective of this work was to evaluate the influence of factors such as banana weight and extraction time during a hot aqueous extraction process on the total soluble solids content of banana. The extract is to be used by the food and beverage industries. The experiments were performed with 105 mL of water, considering the moisture of the ripe banana (65%). Total sugar concentrations were obtained in a beer analyzer and the result expressed in degrees Plato (°P, which is the weight of the extract or the sugar equivalent in 100 g solution at 20 °C), aiming at facilitating the use of these results by the beverage industries. After previous studies of characterization of the fruit and of ripening performance, a 22 full-factorial star design was carried out, and a model was developed to describe the behavior of the dependent variable (total soluble solids) as a function of the factors (banana weight and extraction time), indicating as optimum conditions for extraction 38.5 g of banana at 39.7 min. 相似文献
A simple and rapid development of a stability-indicating LC method for determination of chloroquine diphosphate in the presence of its hydrolysis, oxidative and photolysis degradation products is described. Stress testing showed that chloroquine diphosphate was degraded under basic conditions and by photolytic treatment but was stable under the other stress conditions investigated. Separation of the drug from its degradation products was achieved with a Nova Pack C18 column, 0.01 M PIC B7 and acetonitrile (40:60 v/v) pH 3.6, as mobile phase. Response was linear over the range 0.08–5.70 μg mL−1 (r = 0.996), with limits of detection and quantification (LOD and LOQ) of 0.17 and 0.35 μg mL−1, respectively.
In 2001, two years before the disclosure of the CERT‐associated Cer transfer machinery, N‐(3‐hydroxy‐1‐hydroxymethyl‐3‐phenylpropyl)alkanamides (HPAs) were described as the first, and to date unique, family of intracellular Cer trafficking inhibitors. The dodecanamide derivative, HPA‐12, turned out to be a benchmark as a cellular inhibitor of CERT‐mediated de novo sphingomyelin biosynthesis. In only 15 years after its first disclosure, this compound has prompted a growing number of biological and chemical studies. Its initial chemical development closely paralleled the study of the CERT protein. It was only after its structural revision in 2011 that HPA‐12 received broad attention from the synthetic chemistry community, leading to novel analogues with enhanced protein binding. This Minireview aims at presenting an exhaustive report of the syntheses of HPA‐12 and analogues. Biological activities of this CERT inhibitor and structure–activity relationships are also presented to afford a comprehensive overview of the chemistry and biology of the HPA series. 相似文献