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We present a combination of many-body Green's function theory and Förster-Dexter theory to estimate the excitation energy transfer (EET) coupling in both the isolated and condensed systems. This approach employs the accurate wave functions of excitons, which are derived from the Bethe-Salpeter equation, in the donor and acceptor to set up the electronic coupling terms. Dexter coupling, which arises from the exchange-correlation effect, is evaluated based on the GW method which is a state-of-the-art ab initio theory for the description of self-energy. This approach is applicable to various situations, especially for periodic systems. The approach is tested on some model molecular dimers and compared with other high-level quantum chemistry methods together with the exact supermolecule scheme. Finally, we apply it to study the EET between periodic single-walled carbon nanotubes, exploring the dependence of EET on the chirality of nanotubes and the type of excitation transferred, finding that dark states play key roles in the EET between nanotubes. The EET rate falls as â¼D-12 approximately with the distance D between nanotubes for small D, much faster than the traditional Förster model.
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Phosphocreatine (PCr), a naturally occurring creatine phosphorylated molecule, is a high-energy phosphate compound that is one of the most important substances involved in cell energy metabolism, and also has anti-apoptosis and anti-oxidative stress effects. It is precisely because of its role in maintaining energy homeostasis that PCr is widely used in diseases related to energy damage. In the regulation of cell signal, PCr mainly plays a role through MAPK, NF-κB, PI3K/AKT, ERK/Nrf2/HO-1 and JAK2/STAT3. In clinical applications, PCr is commonly used as a cardioprotective drug, such as ischemic heart disease, myocardial fibrosis, myocardial infarction, arrhythmia, and myocarditis. In recent years, further research on PCr has found that PCr also has a positive role in the treatment of other diseases, including diabetes-induced liver injury, kidney injury, cerebral ischemia-reperfusion injury, and neurodegenerative diseases. In this paper, the literature on PCr in three databases, Web of Sciences, SciFinder, and PubMed, was summarized and analyzed, and the research progress of PCr in recent years was reviewed, hoping to provide help for the expansion of its application in clinical therapy.
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The design of semiconductor catalysts with excellent photocatalytic properties, stability, recyclability, and good separation for the treatment of polluted water is still challenging. In this paper, the ZnO/TiO2 nano-thin films were fabricated using the magnetron sputtering technique and then heating the underlying ZnO layer and the upper TiO2 layer for their respective optimal heating time, i. e. heating ZnO for 3 h and heating TiO2 for 2 h. The as-prepared films were characterized. The results show that the preferred growth of TiO2 grains along the [001] axis, relatively large specific surface area, and increased amounts of surface oxygen vacancies (OVs) were induced to the heterojunction catalysts through this optimized heating strategy, which boosts the photocatalytic activity of ZnO/TiO2 nano-film. The degradation experiment inndicates that the ciprofloxacin (CIP) removal efficiency can reach 97.3% in 2 h duration, which was higher than that of the samples annealed for the same periods. Meanwhile, the prepared ZnO/TiO2 photocatalytic film exhibited favorable stability of 95.5% degradation efficiency after the fourth run and general applicability for the photodegradation of various contantains, whih removed 99.5% of ofloxacin (OFX) and 77.6% of tetracycline (TC) in 2 h and 94.1% of Rhodamine B (RhB) in 1 h. This work is expected to yields a novel insight into the production of heterojunction photocatalysts with excellen ability for photocatalytic degradation of pollutants in the practical industry.
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Antibacterianos , Óxido de Zinco , Óxido de Zinco/química , Calefação , Titânio/químicaRESUMO
The process parameters of electrodeposited Ni-Fe-graphene composite coating on the 7075 aluminum alloy were optimized by the orthogonal experiment. The optimized process parameters were determined as follows: graphene concentration of 1 g L-1, current density of 9 A dm-2, agitation speed of 250 r min-1, and temperature of 60 °C, on the basis of hardness and friction coefficient. The Ni-Fe-graphene composite coating shows an increment of 393.0% in hardness and a decrement of 55.9% in friction coefficient in comparison with 7075 aluminum alloy substrate. The Ni-Fe-graphene composite coating binds tightly to 7075 aluminum alloy with adhesion strength of higher than 6.895 MPa. These make contributions to provide effective protection for aluminum alloys. Surface morphology and corrosion morphology, as well as morphology of the side bound to the substrate, were characterized. The scattered asperities on the surface were proven to be graphene nanoplatelets being wrapped by Ni-Fe, which comprehensively reveals the formation of asperities.
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The incidence rate of diabetes in pregnancy is about 20%, and diabetes in pregnancy will have a long-term impact on the metabolic health of mothers and their offspring. Mothers may have elevated blood glucose, which may lead to blood pressure disease, kidney disease, decreased resistance and secondary infection during pregnancy. The offspring may suffer from abnormal embryonic development, intrauterine growth restriction, obesity, autism, and other adverse consequences. Resveratrol (RSV) is a natural polyphenol compound, which is found in more than 70 plant species and their products, such as Polygonum cuspidatum, seeds of grapes, peanuts, blueberries, bilberries, and cranberries. Previous studies have shown that RSV has a potential beneficial effect on complex pregnancy, including improving the indicators of diabetes and pregnancy diabetes syndrome. This article has reviewed the molecular targets and signaling pathways of RSV, including AMP-activated protein kinase, mitogen-activated protein kinases, silent information regulator sirtuin 1, miR-23a-3p, reactive oxygen species, potassium channels and CX3C chemokine ligand 1, and the effect of RSV on gestational diabetes mellitus (GDM) and its complications. RSV improves the indicators of GDM by improving glucose metabolism and insulin tolerance, regulating blood lipids and plasma adipokines, and modulating embryonic oxidative stress and apoptosis. Furthermore, RSV can ameliorate the GDM complications by reducing oxidative stress, reducing the effects on placentation, reducing the adverse effects on embryonic development, reducing offspring's healthy risk, and so on. Thus, this review is of great significance for providing more options and possibilities for further research on medication of gestational diabetes.
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Perovskites have attracted great interest in optoelectronics and photonics. As a new class of perovskites, metal-free perovskites have drawn growing attention due to the absence of toxic metal elements in them and their wide chemical diversity. Taking MDABCO-NH4I3 (MDBACO = N-methyl-N'-diazabicyclo[2.2.2]octonium) and MDABCO-NH4Br3 as examples, our first-principles calculations discover two fundamental features of metal-free perovskites that should be crucial for their applications. First, their photoluminescence emission originates from halogen vacancies, instead of the self-trapped exciton generally suggested. Second, in the vicinity of a halogen vacancy, optical excitation from the valence bands to the empty defect bands may cause release of H2 and NH3 molecules, which will not only lead to degradation of the perovskite but also quench its photoluminescence. To prevent the degradation and protect the optoelectronic and photonic performances of metal-free perovskites, short-wavelength illumination needs to be shielded.
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With the rapid development of modern industries, the surface quality and performance of metals need to be improved. Composite electrodeposition (co-deposition) has evolved as an important technique for improving the surface performance of metal materials. Herein, a new type of graphene oxide (GO)-reinforced nickel-boron (Ni-B) composite coating was successfully prepared on a 7075 aluminum (Al) alloy by co-deposition. Characterization revealed a significant improvement in the mechanical and anti-corrosion properties of the composite with the incorporation of GOs. The composite showed a rougher, compact, cauliflower-like morphology with finer grains, a higher hardness (1532 HV), a lower rate of wear (5.20 × 10-5 mm3âN-1âm-1), and a lower corrosion rate (33.66 × 10-3 mmây-1) compared with the Ni-B alloy deposit (878 HV, 9.64 × 10-5 mm3âN-1âm-1, and 116.64 × 10-3 mmây-1, respectively). The mechanism by which GOs strengthen the Ni-B matrix is discussed.
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Photocatalytic degradation of organic pollutants in water is a highly efficient and green approach. However, the low quantum efficiency is an intractable obstacle to lower the photocatalytic efficiency of photocatalysts. Herein, the TiO2/ZnO heterojunction thin films combined with surface oxygen vacancies (OVs) were prepared through magnetron sputtering, which was designed to drive rapid bulk and surface separation of charge carriers. The morphology and structural and compositional properties of films were investigated via different techniques such as SEM, XRD, Raman, AFM, and XPS. It has been found that by controlling the O2/Ar ratio, the surface morphology, thickness, chemical composition, and crystal structure can be regulated, ultimately enhancing the photocatalytic performance of the TiO2/ZnO heterostructures. In addition, the heterojunction thin film showed improved photocatalytic properties compared with the other nano-films when the outer TiO2 layer was prepared at an O2/Ar ratio of 10:35. It degraded 88.0% of Rhodamine B (RhB) in 90 min and 90.8% of RhB in 120 min. This was attributed to the heterojunction interface and surface OVs, which accelerated the separation of electron-hole (e-h) pairs.
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Graphitic carbon nitride (g-C3N4), a metal-free two-dimensional photocatalyst, has drawn increasing attention due to its application in photocatalytic water splitting. However, its quantum efficiency is limited by the poor performance of the oxygen evolution reaction (OER). Therefore, it is important to clarify the behavior of photogenerated holes in the OER. In this work, we investigate the energy level alignment using the GW method and the exciton properties using the Bethe-Salpeter equation within the ab initio many-body Green's function theory at the g-C3N4/water interface. We found that the g-C3N4 substrate can elevate energy levels of OH- and H2O molecules at the interface by up to 0.6 eV. This effect can make the electronic levels of OH- surpass the valence band maximum (VBM) of g-C3N4. However, orbital energies of H2O molecules remain far below the VBM of g-C3N4. This indicates that a photogenerated hole after exciting g-C3N4 can relax to OH- instead of neutral H2O. Moreover, OH- could be directly oxidized through electron transfer from OH- to g-C3N4 by light near the optical absorption edge of g-C3N4, which is beneficial for efficient carrier separation at the interface.
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The kinetics of Cu(II) interactions with Susquehanna River (mid-Atlantic, USA) particle suspensions using the copper ion selective electrode (Cu-ISE) method indicated that the concentration of Cu2+ in both the suspension and filtrate was kinetically controlled; the reaction of Cu(II) in the suspension was faster than that in the filtrate. Bioassay tests were performed in continuous flow-through bioassay systems to examine the effect of kinetics of Cu(II) interactions with suspended solids on the toxicity of Cu to Ceriodaphnia dubia. The toxicity curves were displaced to higher total Cu concentration as the reaction time increased, indicating that such interaction of Cu with solids was time dependent. Further, the toxicity curves overlapped for reaction times of 6 and 24 h, indicating that the reaction was relatively rapid and that equilibrium was achieved within 6 h. The survival of organisms was related to the free Cu2+ concentration but deviated from the result for bioassays in which dissolved organic matter (DOM) rather than particles reacted with the added Cu(II) to affect the free Cu2+ concentration. It may be interpreted that, besides the toxic effect of Cu2+, particles exert adverse influences on the organisms.
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Cobre/química , Cobre/toxicidade , Sedimentos Geológicos/química , Poluentes da Água/toxicidade , Animais , Crustáceos , Cinética , Dose Letal Mediana , Ligantes , Análise de SobrevidaRESUMO
OBJECTIVE: To assess efficacy and safety of fulranumab, a fully human monoclonal antibody against nerve growth factor, in patients with diabetic peripheral neuropathic pain (DPNP). METHODS: In this phase II, double-blind, placebo-controlled trial, patients with moderate to severe DPNP were randomized to treatments with fulranumab (1, 3, or 10 mg) or placebo administered subcutaneously every 4 weeks. RESULTS: Because of early study termination (clinical hold) by the US Food and Drug Administration, 77 (intent-to-treat) of the planned 200 patients were enrolled. The primary endpoint, the mean reduction of average daily pain at week 12 compared with baseline, showed a positive dose-response relationship (p = 0.014, 1-sided); the pair-wise comparison between the 10-mg group and placebo was significant (unadjusted p = 0.040, 2-sided). An exploratory responder analysis revealed that a greater proportion of patients in the 10-mg group reported ≥30% reduction in the average DPNP intensity compared with placebo at week 12 (p = 0.006). Although not statistically significant, several secondary endpoints showed directionally similar results to the primary efficacy dose-response relationship. During the combined efficacy and safety extension phases, the top 3 treatment-emergent adverse events in the combined fulranumab group were arthralgia (11%), edema peripheral (11%), and diarrhea (9%). No cases of joint replacement or death were reported. CONCLUSION: Despite early study termination, fulranumab treatment resulted in dose-dependent efficacy and was generally well tolerated. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that in patients with DPNP, fulranumab 10 mg reduces pain by 1.2 points on an 11-point scale compared with placebo.