Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 31
Filter
1.
Adv Sci (Weinh) ; 11(13): e2304349, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38243637

ABSTRACT

Cost-effective non-noble metal-based catalysts for selective hydrogenation with excellent activity, selectivity, and durability are still the holy grail. Herein, an oxygen-doped carbon (OC) chainmail encapsulated dilute Cu-Ni alloy is developed by simple pyrolysis of Cu/Ni-metal-organic framework. The CuNi0.05@OC catalyst displays superior performance for atmospheric pressure transfer hydrogenation of p-chloronitrobenzene and p-nitrophenol, and for hydrogenation of furfural, all in water and with exceptional durability. Comprehensive characterizations confirm the close interactions between the diluted Ni sites, the base Cu, and optimized three-layered graphene chainmail. Theoretical calculations demonstrate that the properly tuned lattice strain and Schottky junction can adjust electron density to facilitate specific adsorption on the active centers, thus enhancing the catalytic activity and selectivity, while the OC shell also offers robust protection. This work provides a simple and environmentally friendly strategy for developing practical heterogeneous catalysts that bring the synergistic effect into play between dilute alloy and functional carbon wrapping.

2.
Small ; 20(7): e2306513, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37803425

ABSTRACT

With the rapid development of performance and long-term stability, bismuth vanadate (BiVO4 ) has emerged as the preferred photoanode in photoelectrochemical tandem devices. Although state-of-the-art BiVO4 photoanodes realize a saturated photocurrent density approaching the theoretical maximum, the fill factor (FF) is still inferior, pulling down the half-cell applied bias photon-to-current efficiency (HC-ABPE). Among the major fundamental limitations are the Fermi level pinning and sluggish surface kinetics at the low applied potentials. This work demonstrates that the plasma-assisted atomic layer deposition technique is capable of addressing these issues by seamlessly installing an angstrom-scale FeNi-layer between BiVO4 and electrolyte. Not only this ultrathin FeNi layer serves as an efficient OER cocatalyst, more importantly, it also effectively passivates the surface states of BiVO4 , de-pins the surface Fermi level, and enlarges the built-in voltage, allowing the photoanode to make optimal use of the photogenerated holes for achieving high FF up to 44% and HC-ABPE to 2.2%. This study offers a new approach for enhancing the FF of photoanodes and provides guidelines for designing efficient unassisted solar fuel devices.

3.
Nano Lett ; 23(24): 11785-11792, 2023 Dec 27.
Article in English | MEDLINE | ID: mdl-38078823

ABSTRACT

Nanostructured bismuth vanadate (BiVO4) is at the forefront of emerging photoanodes in photoelectrochemical tandem devices for solar water splitting owing to the suitable band edge position and efficient charge separation capability. However, the (photo)chemical corrosion involving V5+ dissolution limits the long-term stability of BiVO4. Herein, guided by DFT calculations, we introduce an ALD-derived NiOx catalyst layer on BiVO4 to stabilize the surface Bi-O bonds, facilitate hole extraction, and thus suppress the V5+ dissolution. At the same time, the ALD NiOx catalyst layer could efficiently suppress the surface recombination and accelerate the surface OER kinetics, boosting the half-cell applied bias photon-to-current efficiency of BiVO4 to 2.05%, as well as a fill factor of 47.1%. By adding trace NaVO3 to the electrolyte, the NiOx/BiVO4 photoanode with an illumination area of 10.5 cm2 shows a record operational stability of more than 2100 h.

4.
Iran J Public Health ; 52(7): 1311-1319, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37593500

ABSTRACT

An apoptosis-resistant state determined by apoptotic protein expression is commonly seen in the initiation, progression, and treatment failure stages of human cancer, and anti-tumor drugs targeting apoptotic proteins have been increasingly developed over the past three decades. However, the frequently alternative splicing of apoptotic proteins diminished the ability of targeting drugs to bind to apoptotic proteins and, consequently, limit the drug efficacy. Currently, accumulating evidence has demonstrated that many alternative splicing events have been associated to apoptosis resistance in different cancers. Therefore, the intervention targeting alternative splicing for regulating tumor cell apoptosis is expected to become a new strategy and new direction of antitumor therapy. Here, we present well established alternative splicing events that occur in different apoptosis-related genes and their modification by several approaches with cancer therapeutic purposes.

5.
Nanoscale ; 15(14): 6664-6672, 2023 Apr 06.
Article in English | MEDLINE | ID: mdl-36916503

ABSTRACT

The emergence of organic-inorganic hybrid perovskites with a high µτ product and a high absorption coefficient has made it possible to adopt an aerosol-liquid-solid technology for direct X-ray detectors. The film quality from the ALS process is often compromised, especially on the film surface, when deposited in ambient conditions with uncontrolled humidity. Herein we develop a solvent engineering strategy in the ALS process to obtain high-quality MAPbI3 thick films. The key is the introduction of a molecular additive to intervene and regulate the perovskite crystallization process so that the negative effect of the ALS ambience is minimized. This strategy allows us to prepare direct X-ray detectors with much reduced dark current, enhanced response speed and improved overall performance.

6.
BMJ Open ; 12(3): e053182, 2022 03 16.
Article in English | MEDLINE | ID: mdl-35296476

ABSTRACT

INTRODUCTION: Network meta-analyses have confirmed that paclitaxel plus carboplatin could improve progression-free survival (PFS) and overall survival (OS) compared with platinum alone. However, detailed implementation schedule (weekly or 3-weekly therapy) was not specified in clinical practice guidelines. Evidence from studies is also inconsistent. We will conduct a systematic review and meta-analysis to evaluate the benefits and harms of weekly therapy and 3-weekly therapy of paclitaxel combined with carboplatin in women with ovarian cancer. METHODS: We will search PubMed, EMBASE and the Cochrane Library databases to include relevant randomised controlled trials comparing weekly therapy versus 3-weekly therapy of paclitaxel combined with carboplatin for women with ovarian cancer. Random-effects model will be used to pool data for patient-reported outcomes including survival rate, OS, PFS and adverse events. Grading of Recommendation, Assessment, Development and Evaluation approach will be used to rate the quality of evidence. ETHICS AND DISSEMINATION: This systematic review and meta-analysis will be based on published data and does not therefore require specific ethical approval or consent for participation. The results will be published in a peer-reviewed journal. OSF REGISTRATION NUMBER: 10.17605/OSF.IO/GJUMA.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols , Ovarian Neoplasms , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Carboplatin/therapeutic use , Carcinoma, Ovarian Epithelial , Female , Humans , Meta-Analysis as Topic , Paclitaxel/adverse effects , Systematic Reviews as Topic
7.
J Am Chem Soc ; 144(12): 5247-5252, 2022 Mar 30.
Article in English | MEDLINE | ID: mdl-35298886

ABSTRACT

Understanding the structural nature of the active sites in electrocatalysis is central to discovering general design rules for better catalysts in fuel cells and electrolyzers. Nanostructures are widely used as electrocatalysts, but the location and structure of the active sites within the nanostructure are often unknown. This information is hidden in conventional bulk measurements due to ensemble averaging, hindering direct structure-activity correlation. Herein, we use a single-entity electrochemical approach to reveal the heterogeneity in electrocatalysts via scanning electrochemical cell microscopy (SECCM). Using hematite (α-Fe2O3) nanorods as the model catalyst for oxygen evolution reaction (OER), the electrocatalytic activity is measured at individual nanorods. Finer mapping within a single nanorod shows that the OER activity is consistently higher at the body portion vs the tip of the nanorod. Our results directly suggest the benefit of synthesizing longer hematite nanorods for better OER performance. The origin of the enhanced local activity is explained by the larger fraction of {001} facet exposed on the body compared to the tip. The finding goes beyond OER on hematite nanorods, highlighting the critical role of single-entity activity mapping and colocalized structural characterization in revealing active sites in electrocatalysis.

9.
Angew Chem Int Ed Engl ; 58(52): 19087-19095, 2019 Dec 19.
Article in English | MEDLINE | ID: mdl-31617959

ABSTRACT

The BiVO4 photoelectrochemical (PEC) electrode in tandem with a photovoltaic (PV) cell has shown great potential to become a compact and cost-efficient device for solar hydrogen generation. However, the PEC part is still facing problems such as the poor charge transport efficiency owing to the drag of oxygen vacancy bound polarons. In the present work, to effectively suppress oxygen vacancy formation, a new route has been developed to synthesize BiVO4 photoanodes by using a highly oxidative two-dimensional (2D) precursor, bismuth oxyiodate (BiOIO3 ), as an internal oxidant. With the reduced defects, namely the oxygen vacancies, the bound polarons were released, enabling a fast charge transport inside BiVO4 and doubling the performance in tandem devices based on the oxygen vacancy eliminated BiVO4 . This work is a new avenue for elaborately designing the precursor and breaking the limitation of charge transport for highly efficient PEC-PV solar fuel devices.

10.
Nat Commun ; 10(1): 3687, 2019 Aug 15.
Article in English | MEDLINE | ID: mdl-31417082

ABSTRACT

We herein demonstrate the unusual effectiveness of two strategies in combination to enhance photoelectrochemical water splitting. First, the work function adjustment via molybdenum (Mo) doping significantly reduces the interfacial energy loss and increases the open-circuit photovoltage of bismuth vanadate (BiVO4) photoelectrochemical cells. Second, the creation and optimization of the heterojunction of boron (B) doping carbon nitride (C3N4) and Mo doping BiVO4 to enforce directional charge transfer, accomplished by work function adjustment via B doping for C3N4, substantially boost the charge separation of photo-generated electron-hole pairs at the B-C3N4 and Mo-BiVO4 interface. The synergy between the above efforts have significantly reduced the onset potential, and enhanced charge separation and optical properties of the BiVO4-based photoanode, culminating in achieving a record applied bias photon-to-current efficiency of 2.67% at 0.54 V vs. the reversible hydrogen electrode. This work sheds light on designing and fabricating the semiconductor structures for the next-generation photoelectrodes.

11.
Small ; 15(14): e1804976, 2019 Apr.
Article in English | MEDLINE | ID: mdl-30817092

ABSTRACT

Constructing 3D nanophotonic structures is regarded as an effective means to realize both efficient light absorption and efficient charge separation. However, most of the 3D structures reported so far enhance light trapping beyond the absorption onset wavelength, and thus greatly attentuate or even completely block the long-wavelength light, which could otherwise be efficiently absorbed by narrow-bandgap materials in a Z-scheme or tandem device. In addition, constructing a 3D conductive substrate often involves complex processes causing increased cost and upscaling problems. To overcome these shortcomings, a novel 3D hematite nanorod@nanobowl array nanophotonic structure is designed and fabricated by a low-cost method. This unique structure can enhance light absorption with tunable cutoffs and rationally concentrate photons right above the bowl bottom, enabling efficient charge separation. By loading NiFeOx as a cocatalyst, a high photocurrent density of 3.41 ± 0.2 mA cm-2 at 1.23 V versus reversible hydrogen electrode (RHE) can be obtained, which is 2.35 times that with a planar structure in otherwise the same system.

12.
Health Place ; 53: 258-263, 2018 09.
Article in English | MEDLINE | ID: mdl-30196043

ABSTRACT

BACKGROUND: Studies on environmental exposures during pregnancy commonly use maternal residence at time of delivery, which may result in exposure misclassification and biased estimates of exposure and disease association. Studies on residential mobility during pregnancy are needed in various populations to aid studies of the environmental exposure and birth outcomes. However, there is still a lack of studies investigating residential mobility patterns in Asian populations. METHODS: We analyzed data from 10,542 pregnant women enrolled in a birth cohort study in Lanzhou, China (2010-2012), a major industrial city. Multivariate logistic regression was used to evaluate residential mobility patterns in relation to maternal complications and birth outcomes. RESULTS: Of the participants, 546 (5.2%) moved during pregnancy; among those who moved, 40.5%, 34.8%, and 24.7% moved during the first, second, and third trimester, respectively. Most movers (97.3%) moved once with a mean distance of 3.75 km (range: 1-109 km). More than half (66.1%) of the movers moved within 3 km, 13.9% moved 3-10 km, and 20.0% moved > 10 km. Pregnant women who were > 30 years or multiparous, or who had maternal complications were less likely to have moved during pregnancy. In addition, movers were less likely to deliver infants with birth defects, preterm births, and low birth weight. CONCLUSIONS: Residential mobility was significantly associated with several maternal characteristics and complications during pregnancy. The study also showed a lower likelihood of adverse birth outcomes among movers than non-movers, suggesting that moving might be related to reduce exposure to environmental hazards. These results confirm the hypothesis that residential mobility may be important with respect to exposure misclassification and that this misclassification may vary by subpopulations.


Subject(s)
Population Dynamics/statistics & numerical data , Pregnancy Outcome , Adult , China , Cohort Studies , Environmental Exposure/adverse effects , Female , Humans , Infant, Newborn , Pregnancy , Risk Factors , Socioeconomic Factors
13.
BMC Pregnancy Childbirth ; 17(1): 400, 2017 Dec 01.
Article in English | MEDLINE | ID: mdl-29191156

ABSTRACT

BACKGROUND: To evaluate the independent and joint effects of maternal pre-pregnancy BMI and gestational weight gain (GWG) on the risk of preeclampsia and its subtypes. METHODS: A birth cohort study was conducted from 2010 to 2012 in Lanzhou, China. Three hundred fourty seven pregnant women with preeclampsia and 9516 normotensive women at Gansu Provincial Maternity and Child Care Hospital were included in the present study. Unconditional logistic regression models were used to evaluate the associations between pre-pregnancy BMI, GWG, and risk of preeclampsia and its subtypes. RESULTS: Compared to women with normal pre-pregnancy BMI, those who were overweight/obese had an increased risk of preeclampsia (OR = 1.81; 95%CI: 1.37-2.39). Women with excessive GWG had an increased risk of preeclampsia (OR = 2.28; 95%CI: 1.70-3.05) compared to women with adequate GWG. The observed increased risk was similar for mild-, severe- and late-onset preeclampsia. No association was found for early-onset preeclampsia. Overweight/obese women with excessive GWG had the highest risk of developing preeclampsia compared to normal weight women with no excessive weight gain (OR = 3.78; 95%CI: 2.65-5.41). CONCLUSIONS: Our results suggested that pre-pregnancy BMI and GWG are independent risk factors for preeclampsia and that the risk might vary by preeclampsia subtypes. Our study also proposed a potential synergistic effect of pre-pregnancy BMI and GWG that warrants further investigation.


Subject(s)
Body Mass Index , Obesity/complications , Overweight/complications , Pre-Eclampsia/etiology , Weight Gain , Adult , China , Cohort Studies , Female , Humans , Logistic Models , Obesity/physiopathology , Overweight/physiopathology , Pregnancy , Risk Factors
14.
PLoS One ; 12(11): e0187996, 2017.
Article in English | MEDLINE | ID: mdl-29145433

ABSTRACT

BACKGROUND: It has been reported that folic acid supplementation before and/or during pregnancy could reduce the risk of congenital heart defects (CHDs). However, the results from limited epidemiologic studies have been inconclusive. We investigated the associations between maternal folic acid supplementation, dietary folate intake, and the risk of CHDs. METHODS: A birth cohort study was conducted in 2010-2012 at the Gansu Provincial Maternity & Child Care Hospital in Lanzhou, China. After exclusion of stillbirths and multiple births, a total of 94 births were identified with congenital heart defects, and 9,993 births without any birth defects. Unconditional logistic regression was used to estimate the associations. RESULTS: Compared to non-users, folic acid supplement users before pregnancy had a reduced risk of overall CHDs (OR: 0.42, 95% CI: 0.21-0.86, Ptrend = 0.025) after adjusted for potential confounders. A protective effect was observed for certain subtypes of CHDs (OR: 0.37, 95% CI: 0.16-0.85 for malformation of great arteries; 0.26, 0.10-0.68 for malformation of cardiac septa; 0.34, 0.13-0.93 for Atrial septal defect). A similar protective effect was also seen for multiple CHDs (OR: 0.49, 95% CI: 0.26-0.93, Ptrend = 0.004). Compared with the middle quartiles of dietary folate intake, lower dietary folate intake (<149.88 µg/day) during pregnancy were associated with increased risk of overall CHDs (OR: 1.63, 95% CI: 1.01-2.62) and patent ductus arteriosus (OR: 1.85, 95% CI: 1.03-3.32). Women who were non-user folic acid supplement and lower dietary folate intake have almost 2-fold increased CHDs risk in their offspring. CONCLUSIONS: Our study suggested that folic acid supplementation before pregnancy was associated with a reduced risk of CHDs, lower dietary folate intake during pregnancy was associated with increased risk. The observed associations varied by CHD subtypes. A synergistic effect of dietary folate intake and folic acid supplementation was also observed.


Subject(s)
Diet , Folic Acid/administration & dosage , Heart Defects, Congenital/etiology , Heart Defects, Congenital/prevention & control , Adult , China , Cohort Studies , Female , Humans , Pregnancy
15.
Small ; 13(41)2017 11.
Article in English | MEDLINE | ID: mdl-28895281

ABSTRACT

Recently, researchers have made significant advancement in employing transition metal compound hybrids as anode material for lithium-ion batteries and developing simple preparation of these hybrids. To this end, this study reports a facile and scalable method for fabricating a vanadium oxide-nitride composite encapsulated in amorphous carbon matrix by simply mixing ammonium metavanadate and melamine as anode materials for lithium-ion batteries. By tuning the annealing temperature of the mixture, different hybrids of vanadium oxide-nitride compounds are synthesized. The electrode material prepared at 700 °C, i.e., VM-700, exhibits excellent cyclic stability retaining 92% of its reversible capacity after 200 cycles at a current density of 0.5 A g-1 and attractive rate performance (220 mAh g-1 ) under the current density of up to 2 A g-1 . The outstanding electrochemical properties can be attributed to the synergistic effect from heterojunction form by the vanadium compound hybrids, the improved ability of the excellent conductive carbon for electron transfer, and restraining the expansion and aggregation of vanadium oxide-nitride in cycling. These interesting findings will provide a reference for the preparation of transition metal oxide and nitride composites as well.

16.
Adv Mater ; 29(34)2017 Sep.
Article in English | MEDLINE | ID: mdl-28681991

ABSTRACT

Water splitting into hydrogen and oxygen in order to store light or electric energy requires efficient electrocatalysts for practical application. Cost-effectiveness, abundance, and efficiency are the major challenges of the electrocatalysts. Herein, this paper reports the use of low-cost 304-type stainless steel mesh as suitable electrocatalysts for splitting of water. The commercial and self-support stainless steel mesh is subjected to exfoliation and heteroatom doping processes. The modified stainless steel electrocatalyst displays higher oxygen evolution reaction property than the commercial IrO2 , and comparable hydrogen evolution reaction property with that of Pt. More importantly, an all-stainless-steel-based alkaline electrolyzer (denoted as NESSP//NESS) is designed for the first time, which possesses outstanding stability along with lower overall voltage than the conventional Pt//IrO2 electrolyzer at increasing current densities. The remarkable electrocatalytic properties of the stainless steel electrode can be attributed to the unique exfoliated-surface morphology, heteroatom doping, and synergistic effect from the uniform distribution of the interconnected elemental compositions. This work creates prospects to the utilization of low-cost, highly active, and ultradurable electrocatalysts for electrochemical energy conversion.

18.
Nano Lett ; 17(4): 2490-2495, 2017 04 12.
Article in English | MEDLINE | ID: mdl-28334530

ABSTRACT

High-temperature activation has been commonly used to boost the photoelectrochemical (PEC) performance of hematite nanowires for water oxidation, by inducing Sn diffusion from fluorine-doped tin oxide (FTO) substrate into hematite. Yet, hematite nanowires thermally annealed at high temperature suffer from two major drawbacks that negatively affect their performance. First, the structural deformation reduces light absorption capability of nanowire. Second, this "passive" doping method leads to nonuniform distribution of Sn dopant in nanowire and limits the Sn doping concentration. Both factors impair the electrochemical properties of hematite nanowire. Here we demonstrate a silica encapsulation method that is able to simultaneously retain the hematite nanowire morphology even after high-temperature calcination at 800 °C and improve the concentration and uniformity of dopant distribution along the nanowire growth axis. The capability of retaining nanowire morphology allows tuning the nanowire length for optimal light absorption. Uniform distribution of Sn doping enhances the donor density and charge transport of hematite nanowire. The morphology and doping engineered hematite nanowire photoanode decorated with a cobalt oxide-based oxygen evolution reaction (OER) catalyst achieves an outstanding photocurrent density of 2.2 mA cm-2 at 0.23 V vs Ag/AgCl. This work provides important insights on how the morphology and doping uniformity of hematite photoanodes affect their PEC performance.

19.
Biosci Biotechnol Biochem ; 81(3): 441-444, 2017 Mar.
Article in English | MEDLINE | ID: mdl-28114857

ABSTRACT

A novel indole derivative (1) and three known compounds (2-4) were isolated from the fruiting bodies of Tricholoma flavovirens. Their structures were determined or identified by the interpretation of spectroscopic data. Compounds 1 and 2 promoted root growth of lettuce and inhibited hypocotyl growth at 1 µmol/paper. Compound 3 inhibited hypocotyl and root growth at 100 nmol/paper.


Subject(s)
Fruiting Bodies, Fungal/chemistry , Plant Growth Regulators/chemistry , Plant Growth Regulators/pharmacology , Tricholoma/chemistry , Acetamides/chemistry , Acetamides/pharmacology , Benzofurans/chemistry , Benzofurans/pharmacology , Hypocotyl/drug effects , Hypocotyl/growth & development , Indoles/chemistry , Lactuca/drug effects , Lactuca/growth & development , Magnetic Resonance Spectroscopy , Molecular Structure , Plant Roots/drug effects , Plant Roots/growth & development
20.
ACS Appl Mater Interfaces ; 8(41): 27859-27867, 2016 Oct 19.
Article in English | MEDLINE | ID: mdl-27696814

ABSTRACT

Defect engineering is regarded as one of the most active projects to monitor the chemical and physical properties of materials, which is expected to increase the photocatalytic activities of the materials. Herein, oxygen vacancies and IO3- doping are introduced into BiOI nanosheets via adding NaH2PO2, which can impact the charge carrier dynamics of BiOI photocatalysts, such as its excitation, separation, trap, and transfer. These oxygen-deficient BiOI nanosheets display attractive photocatalytic activities of gaseous formaldehyde degradation and methyl orange under visible light irradiation, which are 5 and 3.5 times higher than the BiOI samples, respectively. Moreover, the comodified BiOI also displayed superior cycling stability and can be used for practical application. This work not only develops an effective strategy for fabricating oxygen vacancies but also offers deep insight into the impact of surface defects in enhancing photocatalysis.

SELECTION OF CITATIONS
SEARCH DETAIL
...