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One of the key challenges in artificial photosynthesis is to design a photocatalyst that can bind and activate the CO2 molecule with the smallest possible activation energy and produce selective hydrocarbon products. In this contribution, a combined experimental and computational study on Ni-nanocluster loaded black TiO2 (Ni/TiO2[Vo] ) with built-in dual active sites for selective photocatalytic CO2 conversion is reported. The findings reveal that the synergistic effects of deliberately induced Ni nanoclusters and oxygen vacancies provide (1) energetically stable CO2 binding sites with the lowest activation energy (0.08 eV), (2) highly reactive sites, (3) a fast electron transfer pathway, and (4) enhanced light harvesting by lowering the bandgap. The Ni/TiO2[Vo] photocatalyst has demonstrated highly selective and enhanced photocatalytic activity of more than 18 times higher solar fuel production than the commercial TiO2 (P-25). An insight into the mechanisms of interfacial charge transfer and product formation is explored.
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Background: Hepatocellular carcinoma (HCC) is a common malignancy. Ferroptosis and cuproptosis promote HCC spread and proliferation. While fewer studies have combined ferroptosis and cuproptosis to construct prognostic signature of HCC. This work attempts to establish a novel scoring system for predicting HCC prognosis, immunotherapy, and medication sensitivity based on ferroptosis-related genes (FRGs) and cuproptosis-related genes (CRGs). Methods: FerrDb and previous literature were used to identify FRGs. CRGs came from original research. The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) databases included the HCC transcriptional profile and clinical information [survival time, survival status, age, gender, Tumor Node Metastasis (TNM) stage, etc.]. Correlation, Cox, and least absolute shrinkage and selection operator (LASSO) regression analyses were used to narrow down prognostic genes and develop an HCC risk model. Using "caret", R separated TCGA-HCC samples into a training risk set and an internal test risk set. As external validation, we used ICGC samples. We employed Kaplan-Meier analysis and receiver operating characteristic (ROC) curve to evaluate the model's clinical efficacy. CIBERSORT and TIMER measured immunocytic infiltration in high- and low-risk populations. Results: TXNRD1 [hazard ratio (HR) =1.477, P<0.001], FTL (HR =1.373, P=0.001), GPX4 (HR =1.650, P=0.004), PRDX1 (HR =1.576, P=0.002), VDAC2 (HR =1.728, P=0.008), OTUB1 (HR =1.826, P=0.002), NRAS (HR =1.596, P=0.005), SLC38A1 (HR =1.290, P=0.002), and SLC1A5 (HR =1.306, P<0.001) were distinguished to build predictive model. In both the model cohort (P<0.001) and the validation cohort (P<0.05), low-risk patients had superior overall survival (OS). The areas under the curve (AUCs) of the ROC curves in the training cohort (1-, 3-, and 5-year AUCs: 0.751, 0.727, and 0.743), internal validation cohort (1-, 3-, and 5-year AUCs: 0.826, 0.624, and 0.589), and ICGC cohort (1-, 3-, and 5-year AUCs: 0.699, 0.702, and 0.568) were calculated. Infiltration of immune cells and immunological checkpoints were also connected with our signature. Treatments with BI.2536, Epothilone.B, Gemcitabine, Mitomycin.C, Obatoclax. Mesylate, and Sunitinib may profit high-risk patients. Conclusions: We analyzed FRGs and CRGs profiles in HCC and established a unique risk model for treatment and prognosis. Our data highlight FRGs and CRGs in clinical practice and suggest ferroptosis and cuproptosis may be therapeutic targets for HCC patients. To validate the model's clinical efficacy, more HCC cases and prospective clinical assessments are needed.
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Thoracic outlet syndrome(TOS) are constellation of symptoms caused by compression of the neurovascular bundle including the brachial plexus, the subclavian artery and the subclavian vein at the thoracic outlet region. It includes neurogenic TOS, venus TOS, arterial TOS, and neurogenic TOS is the most common type. TOS has varied manifestations and lack of confirmatory testing, therefore, the diagnosis should be conbination with thorough history, physical examination and associated supplementary examinations. Conservative and surgical treatment can be choosed for TOS and the outcomes are generally good. Conservative management is the initial treatment strategy for neurogenic TOS. In cases of symptomatic vascular TOS and neurovascular TOS, which has been failed by conservative treatment, surgery should be considered more promptly.
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Plexo Braquial , Síndrome do Desfiladeiro Torácico , Tratamento Conservador , Humanos , Exame Físico , Síndrome do Desfiladeiro Torácico/diagnóstico , Síndrome do Desfiladeiro Torácico/terapiaRESUMO
Photocatalytic formation of hydrocarbons using solar energy via artificial photosynthesis is a highly desirable renewable-energy source for replacing conventional fossil fuels. Using an L-cysteine-based hydrothermal process, here we synthesize a carbon-doped SnS2 (SnS2-C) metal dichalcogenide nanostructure, which exhibits a highly active and selective photocatalytic conversion of CO2 to hydrocarbons under visible-light. The interstitial carbon doping induced microstrain in the SnS2 lattice, resulting in different photophysical properties as compared with undoped SnS2. This SnS2-C photocatalyst significantly enhances the CO2 reduction activity under visible light, attaining a photochemical quantum efficiency of above 0.7%. The SnS2-C photocatalyst represents an important contribution towards high quantum efficiency artificial photosynthesis based on gas phase photocatalytic CO2 reduction under visible light, where the in situ carbon-doped SnS2 nanostructure improves the stability and the light harvesting and charge separation efficiency, and significantly enhances the photocatalytic activity.
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Production of hydrogen from water electrolysis has stimulated the search of sustainable electrocatalysts as possible alternatives. Recently, cobalt phosphide (CoP) and molybdenum phosphide (MoP) received great attention owing to their superior catalytic activity and stability towards the hydrogen evolution reaction (HER) which rivals platinum catalysts. In this study, we synthesize and study a series of catalysts based on hybrids of CoP and MoP with different Co/Mo ratio. The HER activity shows a volcano shape and reaches a maximum for Co/Mo = 1. Tafel analysis indicates a change in the dominating step of Volmer-Hyrovský mechanism. Interestingly, X-ray diffraction patterns confirmed a major ternary interstitial hexagonal CoMoP2 crystal phase is formed which enhances the electrochemical activity.
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Pseudo-dendritic polyethyleniminated poly(oxypropylene)diamine (D400(EI)(20)) was used as a stabilizer and promoter to prepare Pt nanoparticles in aqueous solution, which was then deposited on carbon surface followed by calcination. After being deposited on carbon surface, no Pt(0) could be detected in the solution phase. In all steps, the increasing molar ratio of the amino groups of D400(EI)(20) to H(2)PtCl(6) ([N]/[Pt]) drastically reduced the size and the polydispersity and kept a constant low value after [N]/[Pt] = 20. Under a [N]/[Pt] ratio of 20, the particle sizes obtained from transmission electron microscopy (TEM) were very small in solution (2.7-2.4 nm) and remained the same after being deposited on carbon surface (2.7-2.4 nm), and were only slightly increased to 3.6-3.0 nm after calcination. The stabilizing ability of D400(EI)(20) to Pt on carbon surface before and after calcination can be interpreted by the existence of binding energy between Pt and amine nitrogen. The X-ray diffraction (XRD) pattern together with the TEM image reveals that the obtained Pt nanoparticles exist in single-crystal form. The results of photoelectron spectroscopy (XPS) evidence that the metallic Pt(0) rather than the oxidized Pt is the predominant species in the Pt/C catalysts. The electrochemical active surface (EAS) area of the Pt/C catalyst is only slightly higher than that of the E-TEK Pt/C catalyst, but the utilization factor (93.4%) is remarkably higher than the latter (62.8%). The increasing time of thermal treatment increases the crystallinity of Pt(0) on carbon, accompanied by the increasing EAS areas, which corresponds to its enhanced electrocatalytic performance to methanol oxidation.
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A new type of surfactant with a hydrophile of dendritic polyethylenimine (C(12)(EI)(7)) was synthesized by a cationic polymerization of dodecylamine with aziridine and was used as a stabilizer to prepare Pt colloid, which is then used in situ to prepare carbon-supported Pt nanoparticles. The effects of supporting carbon, surfactant concentration, and calcination time on the nanoparticle size and catalytic performance were determined from the transmission electron microscopic analyses and cyclic voltammograms. In the presence of carbon, the Pt particle size increased slightly with lower C(12)(EI)(7) content, while those with higher C(12)(EI)(7) concentrations remained unchanged. For the heat-treated Pt/C catalyst, the molar ratio of C(12)(EI)(7) to H(2)PtCl(6) ([N]/[Pt] ratio) dominated the growth of Pt nanoparticles. The size decreased from 7.6 nm for a [N]/[Pt] ratio of 5 to 3.8 nm for a [N]/[Pt] ratio of 40. X-ray photoelectron spectroscopy revealed that metallic Pt(0) (81.6%) predominated the Pt species in the heat-treated catalyst, which is more than the commercial E-TEK catalyst. The data show clearly that thermal treatment had successively removed the stabilizing shells; moreover, it did not cause serious aggregation of particles in the presence of C(12)(EI)(7) and thus enhanced the catalytic activity. The interaction between Pt and C(12)(EI)(7) were studied and were explained in terms of a mechanism of dual-functional stabilization both on carbon and in the thermal treatment.
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A series of poly(oxypropylene)diamines D230, D400, D2000, and D4000, having molecular weights of hydrophobic segments of 230, 400, 2000, and 4000, were used as ligands to synthesize self-organized gold nanocrystals. Ligand exchange significantly reduced the average particle size and the polydispersity of nanocrystals, and this effect was more remarkable as the molar ratio of amine groups to Au3+ ions ([N]/[Au3+] ratio) was increased. Under the same [N]/[Au3+] ratio of 100, D2000 generated an ordered 2D-monolayer; however, D230 and D400 colloids formed mainly a densely packed 3D structure with minor 2-D layers, and D4000 presented disordered 3D and 2D structures. The gap among the nanoparticles was found to be increased with the increasing molecular weight of the hydrophobic segment of ligands, accompanied by the decreasing wavelength of UV-vis absorption bands. This increased gap can be interpreted as the ligand thickness calculated from the equation of steric force increasing with increasing molecular weight of the hydrophobic segment. The potential energies obtained from the calculated ligand thickness according to the soft sphere model show more steep potential wells for D230 and D400 colloids than that for the D2000 colloid. This explains why the aggregation hardly occurred for the gold nanoparticles obtained under D2000, where the nanoparticles are single crystals having face center crystal structure with a lattice constant of 2.36 A and have grain sizes close to the average particle sizes, evidenced from the results of transmission electron microscopy and X-ray diffraction spectroscopy.
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[reaction: see text] Stable 4-[2-isopropylidene]-phenol carbocation, IPP cation 1, was generated readily by addition of bisphenol A in concentrated sulfuric acid at ambient temperature, and the cation could be used for facile syntheses of 4-isopropenyl phenol (IPP), IPP dimers, and spiro-bisphenol derivatives.
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Alternatives to platinum-based catalysts are required to sustainably produce hydrogen from water at low overpotentials. Progress has been made in utilizing tungsten carbide-based catalysts, however, their performance is currently limited by the density and reactivity of active sites, and insufficient stability in acidic electrolytes. We report highly active graphene nanoplatelet-supported tungsten carbide-nitride nanocomposites prepared via an inâ situ solid-state approach. This nanocomposite catalyzes the hydrogen evolution reaction with very low overpotential and is stable operating for at least 300â h in harsh acidic conditions. The synthetic approach offers a great advantage in terms of structural control and kinetics improvement.
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Grafite/química , Hidrogênio/química , Nanoestruturas/química , Compostos de Nitrogênio/química , Compostos de Tungstênio/química , Catálise , Eletroquímica , Modelos Moleculares , Conformação MolecularRESUMO
The production of hydrogen by the electrolysis of water, a sustainable and greenhouse-gas-free source, requires an efficient and abundant electrocatalyst that minimizes energy consumption. Interest in transition metal carbides and nitrides has been aroused by their promising properties that make them potential substitutes for Pt-group metals as catalysts for the hydrogen evolution reaction. In this review, we discuss systematically the recent progress in the development of group IV-VI metal carbides and nitrides toward the hydrogen evolution reaction. Some strategies for designing such catalysts and improving their efficiency and reliability, including nanostructuring, optimizing hydrogen binding energy, interaction with the supporting material, and exploiting hybrid structures, are highlighted. We conclude with an outlook on the challenges in designing future HER electrocatalysts.
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Stability is one of the main requirements for commercializing fuel cell electrocatalysts for automotive applications. Platinum is the best-known catalyst for oxygen reduction in cathodes, but it undergoes dissolution during potential changes while driving electric vehicles, thus hampering commercial adoption. Here we report a new class of highly stable, active electrocatalysts comprising platinum monolayers on palladium-gold alloy nanoparticles. In fuel-cell tests, this electrocatalyst with its ultra-low platinum content showed minimal degradation in activity over 100,000 cycles between potentials 0.6 and 1.0 V. Under more severe conditions with a potential range of 0.6-1.4 V, again we registered no marked losses in platinum and gold despite the dissolution of palladium. These data coupled with theoretical analyses demonstrated that adding a small amount of gold to palladium and forming highly uniform nanoparticle cores make the platinum monolayer electrocatalyst significantly tolerant and very promising for the automotive application of fuel cells.
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Ouro/química , Paládio/química , Platina/química , Catálise , Eletroquímica , Nanotecnologia , OxirreduçãoRESUMO
Manipulating and discriminating biological cells of interest using microfluidic and micro total analysis system (µTAS) devices have potential applications in clinical diagnosis and medicine. Cellular focusing in microfluidic devices is a prerequisite for medical applications, such as cell sorting, cell counting, or flow cytometry. In the present study, an insulator-based dielectrophoretic microdevice is designed for the simultaneous filtration and focusing of biological cells. The cells are introduced into the microchannel and hydrodynamically pre-confined by funnel-shaped insulating structures close to the inlet. There are ten sets of X-patterned insulating structures in the microfluidic channel. The main function of the first five sets of insulating structures is to guide the cells by negative dielectrophoretic responses (viable HeLa cells) into the center region of the microchannel. The positive dielectrophoretic cells (dead HeLa cells) are attracted to regions with a high electric-field gradient generated at the edges of the insulating structures. The remaining five sets of insulating structures are mainly used to focus negative dielectrophoretic cells that have escaped from the upstream region. Experiments employing a mixture of dead and viable HeLa cells are conducted to demonstrate the effectiveness of the proposed design. The results indicate that the performance of both filtration and focusing improves with the increasing strength of the applied electric field and a decreasing inlet sample flow rate, which agrees with the trend predicted by the numerical simulations. The filtration efficiency, which is quantitatively investigated, is up to 88% at an applied voltage of 50 V peak-to-peak (1 kHz) and a sample flow rate of 0.5 µl/min. The proposed device can focus viable cells into a single file using a voltage of 35 V peak-to-peak (1 kHz) at a sample flow rate of 1.0 µl/min.
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OBJECTIVE: To explore the different therapeutic effects of comminuted clavicular fracture with acromioclavicular external fixtatior and DCP internal fixation. METHODS: There were 768 cases of comminuted clavicular fracture involved in the study. Among them, 528 patients (321 male and 207 female, aged from 15 to 82 years) treated with acromioclavicular external fixator, in which there were 165 cases of three parts fracture and 363 cases of more than three parts fracture; 240 patients (152 males and 88 females, aged from 17 to 64 years) treated with the internal fixation, in which there were 178 cases of three parts fracture and 62 cases of more than three parts fracture. The time between injury and treatment was 1.3 days (range, 2 h to 8 days). The results were evaluated according to Neer scoring system. RESULTS: All the cases were followed up from 8 to 24 months. For treatment of fracture more than three parts, there was significant difference between acromioclavicular external fixation group and internal fixation group in nonunion rate (chi2=44.17, P<0.05) and in Neer scores (t=5.284, P<0.05). CONCLUSION: Treatment with DCP internal fixation which matching the AO principles can obtain anatomic reduction, firm fixation and early functional exercise; however, treatment with self-designed acromioclavicular external fixator is an ideal therapeutic method as it has, early union of the fracture and good functional outcome with seldom complications.
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Clavícula/lesões , Fixadores Externos , Fixação Interna de Fraturas/métodos , Fraturas Cominutivas/cirurgia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
<p><b>OBJECTIVE</b>To summarize the clinicopathological features and prognosis of malignant ovarian neoplasms complicating pregnancy and explore the rational treatment.</p><p><b>METHODS</b>The clinical data of 38 patients with malignant ovarian neoplasms complicating pregnancy were retrospectively analyzed,and the intra-surgical pathological sections were reviewed. International Federation of Gynecology and Obstetrics (FIGO) staging system (1988) was applied.</p><p><b>RESULTS</b>Of these 38 patients,the malignancies included epithelial ovarian cancer (n=9, 23.7%), epithelial borderline ovarian tumor (n=13, 34.2%),ovarian malignant germ cell tumors (n=11, 28.9%), sex cord stromal tumors (n=3, 7.9%), and metastatic tumor from gastrointestinal tracts (n=2, 5.3%). Twenty-seven patients (71.1%) were at stage I. The pregnancy outcomes included termination in the first trimester (n=8), full-term vaginal delivery (n=6), full-term Cesarean section (n=15), and therapeutical Cesarean section for premature birth (n=9). One newborn died,and the remaining 29 survived in a healthy status. All patients underwent surgical treatment,among whom two patients received surgeries during pregnancy. Patients were followed up for (40.5±38.5) months,during which one patient was lost to follow-up, 7 died, 1 survived with tumor, and 29 (76.3%) survived free of tumors.</p><p><b>CONCLUSIONS</b>The management of ovarian malignancies complicating pregnancy should be individualized. Both surgical treatment and chemotherapy are relatively safe in the second and third trimesters. Satisfactory prognosis can be expected after appropriate treatment.</p>