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The performance of a chemical reaction is critically dependent on the electronic and/or geometric structures of a material in heterogeneous catalysis. Over the past century, the Sabatier principle has already provided a conceptual framework for optimal catalyst design by adjusting the electronic structure of the catalytic material via a change in composition. Beyond composition, it is essential to recognize that the geometric atomic structures of a catalyst, encompassing terraces, edges, steps, kinks, and corners, have a substantial impact on the activity and selectivity of a chemical reaction. Crystal-phase engineering has the capacity to bring about substantial alterations in the electronic and geometric configurations of a catalyst, enabling control over coordination numbers, morphological features, and the arrangement of surface atoms. Modulating the crystallographic phase is therefore an important strategy for improving the stability, activity, and selectivity of catalytic materials. Nonetheless, a complete understanding of how the performance depends on the crystal phase of a catalyst remains elusive, primarily due to the absence of a molecular-level view of active sites across various crystal phases. In this review, we primarily focus on assessing the dependence of catalytic performance on crystal phases to elucidate the challenges and complexities inherent in heterogeneous catalysis, ultimately aiming for improved catalyst design.
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The development of alternative alloy catalysts with high activity, surpassing platinum group metals, for the oxygen reduction reaction (ORR) is urgently needed in the field of electrocatalysis. The Ag-based single-atom alloy (AgSAA) cluster has been proposed as a promising catalyst for the ORR; however, enhancing its activity under operational conditions remains challenging due to limited insights into its actual active site. Here, we demonstrate that the operando formation of the MO x (OH) y complex serves as the key active site for catalyzing the ORR over AgSAA cluster catalysts, as revealed through comprehensive neural network potential molecular dynamics simulations combined with first-principles calculations. The volcano plot of the ORR over the MO x (OH) y complex addresses the gaps inherent in traditional metallic alloy models for pure AgSAA cluster catalysts in ORR catalysis. The appropriate orbital hybridization between OH and the dopant metal in the MO x (OH) y complexes indicated that the Ag54Co1, Ag54Pd1, and Ag54Au1 clusters are optimal AgSAA catalysts for the ORR. Our work underscores the significance of theoretical modeling considering the reaction atmosphere in uncovering the true active site for the ORR, which can be extended to other reaction systems for rational catalyst design.
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OBJECTIVE: To explore asurgical methods for replantation of severed finger. METHODS: From January 2018 to November 2022, 8 amputated-finger patients were performed surgical reconstructions by using polyfoliate free flaps with the first dorsal metatarsal artery, including 7 males and 1 female, aged from 20 to 55 years old, and defect areas ranged from (1.0 to 2.0) cm×(3.0 to 4.5) cm. Finger pulp sensation, shape and other relevant parameters were assessed following the upper extremity functional evaluation standard, which was put forward by Hand Surgery Branch of Chinese Medical Association. And maryland foot functional score was used to evaluate foot function. RESULTS: Amputated fingers and flaps of all the 8 patients were survived. All patients were followed up for 4 to 20 months, their finger color and temperature tured to normal, with good wear-resistance and cold-resistance. According to Hand Surgery Branch of Chinese Medical Association, functional score ranged 61 to 92;4 patients got excellent result and 4 good. Maryland foot functional score ranged from 93 to 100;and 8 patients got excellent result. CONCLUSION: It is feasible to repair severed fingers with soft tissue defects using polyfoliate free flaps that driven by the flippers of the first and second toes of the foot. This method ccould bridge blood vessels, increase soft tissue volume of the injured finger, and avoid finger shortening, with high patient satisfaction.
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Pé , Procedimentos de Cirurgia Plástica , Masculino , Humanos , Feminino , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Pé/cirurgia , Extremidade Inferior , Retalhos Cirúrgicos , Dedos do PéRESUMO
Epigallocatechin gallate (EGCG) has the effect to protect skin from ultraviolet B (UVB) induced damages, but it is unstable under ambient conditions, being susceptible to become brown in color. Gallocatechin gallate (GCG), an epimer counterpart of EGCG, is more stable chemically than EGCG. The potential effects of GCG against UVB-induced skin damages has not been available. The objective of this study was to investigate the protective effects of GCG against UVB-induced skin photodamages. GCG was topically applied on the skin of hairless mice at three dosage levels (LL, 12.5 mg/mL; ML 25 mg/mL; HL, 50 mg/mL), with EGCG and a commercially available baby sunscreen lotion SPF50 PA+++ as control. The mice were then irradiated by UVB (fluence rate 1.7 µmol/m2 s) for 45 min. The treatments were carried out once a day for 6 consecutive days. Skin measurements and histological studies were performed at the end of experiment. The results show that GCG treatments at ML and HL levels inhibited the increase in levels of skin oil and pigmentation induced by UVB irradiation, and improved the skin elasticity and collagen fibers. GCG at ML and HL levels inhibited the formation of melanosomes and aberrations in mitochondria of UVB-irradiated skin in hairless mice. It is concluded that GCG protected skin from UVB-induced photodamages by improving skin elasticity and collagen fibers, and inhibiting aberrations in mitochondria and formation of melanosomes.
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Catequina/análogos & derivados , Pele/efeitos dos fármacos , Pele/efeitos da radiação , Protetores Solares/administração & dosagem , Raios Ultravioleta/efeitos adversos , Administração Cutânea , Animais , Catequina/administração & dosagem , Feminino , Masculino , Melanossomas/efeitos dos fármacos , Melanossomas/efeitos da radiação , Camundongos , Camundongos Pelados , Camundongos Endogâmicos BALB C , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/efeitos da radiação , Vaselina/administração & dosagem , Doses de RadiaçãoRESUMO
ScPO4:Eu3+, Tb3+ phosphors with tuned emission color were prepared through high temperature solid-state reaction. The structure, morphology and photoluminescence properties of the title samples were collected by XRD, SEM and fluorescence spectrophotometer, respectively. Co-doping Eu3+ and Tb3+ in ScPO4 does not change the body-centered tetragonal structure of the host. And the morphology remains essentially unchanged except for slight agglomeration. Changing the ratio of Tb3+/Eu3+, the tuned emission can be achieved, the color could be adjusted from green through yellow to orange-red. The ScPO4:0.03Tb3+, 0.03Eu3+ phosphor with high thermal stability as the single matrix phosphor can be suitable for the NUV-pumped white LED. The white LED with a color rendering index of 86.5 and a correlated color temperature of 3470 K has been generated by packaging BAM:Eu2+ with ScPO4:0.03Tb3+, 0.03Eu3+ on an NUV-InGaN chip.
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Európio , LuminescênciaRESUMO
OBJECTIVE: Through reviewing the relevant literature from the past decades, to summarize the assessment and management of fractures of the clavicle, and provide an overview of the clinical results of a range of treatment options. DATA SOURCES: The data analyzed in this review are mainly from articles included in PubMed and EMBASE, published from 1960 to 2015. STUDY SELECTION: Studies involving assessment of fractures of the clavicle were reviewed. Further literatures were gathered regarding the conservative and surgical treatment of these fractures, including the methods of fixation and the surgical approaches used. Both conservative and surgical treatments were then compared and contrasted. RESULTS: Through retrieving and reading the abstract, a total of 42 representative articles were selected, which covered all aspects of the conservative treatment and surgical treatment, and compared the advantages and disadvantages of different treatment options. CONCLUSIONS: Although the majority of recent data suggest that surgery may be more appropriate as it improves functional outcome and reduces the risk of complications, we recommend that the treatment should be individually assessed.