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1.
Water Res ; 194: 116933, 2021 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-33618106

RESUMO

Reservoirs have been constructed as clean energy sources in recent decades with various environmental impacts. Karst rivers typically exhibit high dissolved inorganic carbon (DIC) concentrations, whether and how reservoirs affect carbon cycling, especially organic carbon (OC)-related biogeochemical processes in karst rivers, are unclear. To fill this knowledge gap, multiple tracer methods (including fluorescence excitation-emission matrix (EEM), ultraviolet (UV) absorption, and stable carbon (δ13C) and radiocarbon (Δ14C) isotopes) were utilized to track composition and property changes of both particulate OC (POC) and dissolved OC (DOC) along river-transition-reservoir transects in the Southwest China karst area. The changes in chemical properties indicated that from the river to the reservoir, terrestrial POC is largely replaced by phytoplankton-derived OC, while gradual coloured dissolved organic matter (CDOM) removal and addition of phytoplankton-derived OC to the DOC pool occurred as water flowed to the reservoir. Higher primary production in the transition area than that in the reservoir area was observed, which may be caused by nutrient released from suspended particles. Within the reservoir, the production surpassed degradation in the upper 5 m, resulting in a net DIC transformation into DOC and POC and terrestrial DOM degradation. The primary production was then gradually weakened and microbial degradation became more important down the profile. It is estimated that ~3.1-6.3 mg L-1 (~15.5-31.5 mg-C m-2 (~10-21%)) DIC was integrated into the OC pool through the biological carbon pump (BCP) process in the upper 5 m in the transition and reservoir areas. Our results emphasize the reservoir impact on riverine OC transport, and due to their characteristics, karst areas exhibit a higher BCP potential which is sensitive to human activities (more nutrient are provided) than non-karst areas.

2.
J Health Psychol ; : 1359105321990802, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33586460

RESUMO

The present study was designed to examine a possible two mediator model with both body surveillance and body shame mediating the association of selfie behavior with cosmetic surgery consideration in young adult women. A sample of 588 young adult women participated in this study and completed questionnaires regarding selfie behavior, body surveillance, body shame, and cosmetic surgery consideration. Results indicated that selfie behavior was positively related to cosmetic surgery consideration. In addition, the mediation analysis by PROCESS revealed that body surveillance and body shame mediated the relation between selfie behavior and cosmetic surgery consideration. These findings add to the extant literature by suggesting that selfie behavior may be a new experience of self-objectification, which provide new insights into the relation between selfie activities and cosmetic surgery consideration in young women.

3.
Chin Med J (Engl) ; 134(4): 410-412, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33605601
4.
J Cell Mol Med ; 2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33534963

RESUMO

Inflammation is a biological process that exists in a large number of diseases. If the magnitude or duration of inflammation becomes uncontrolled, inflammation may cause pathological damage to the host. HMGB1 and NF-κB have been shown to play pivotal roles in inflammation-related diseases. New drugs aimed at inhibiting HMGB1 expression have become a key research focus. In the present study, we showed that paeonol (Pae), the main active component of Paeonia suffruticosa, decreases the expression of inflammatory cytokines and inhibits the translocation of HMGB1 induced by lipopolysaccharide (LPS). By constructing HMGB1-overexpressing (HMGB1+ ) and HMGB1-mutant (HMGB1m ) RAW264.7 cells, we found that the nuclear HMGB1 could induce an LPS-tolerant state in RAW264.7 cells and that paeonol had no influence on the expression of inflammatory cytokines in HMGB1m RAW264.7 cells. In addition, the anti-inflammatory property of paeonol was lost in HMGB1 conditional knockout mice, indicating that HMGB1 is a target of paeonol and a mediator through which paeonol exerts its anti-inflammatory function. Additionally, we also found that HMGB1 and P50 competitively bound with P65, thus inactivating the NF-κB pathway. Our research confirmed the anti-inflammation property of paeonol and suggests that inhibiting the translocation of HMGB1 could be a new strategy for treating inflammation.

5.
Biol Open ; 2021 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-33593793

RESUMO

One of the main functions of physiological color change is thermoregulation. This change occurs much more rapidly than morphological color change, but the underlying mechanism remains poorly understood. Here, we studied the thermal dependence and molecular basis of physiological color change in lizards using Takydromus septentrionalis (Lacertidae) as the model system. Body color was thermally sensitive, becoming increasingly light as body temperatures deviated from the level (∼30 °C) preferred by this species. We identified 3,389 differentially expressed genes (DEGs) between lizards at 24 °C and 30 °C, and 1,097 DEGs between lizards at 36 °C and 30 °C. Temperature affected the cAMP signal pathway, motor proteins, cytoskeleton, and the expression of genes related to melanocyte-stimulating hormone (MSH) and melanocyte-concentrating hormone (MCH). Our data suggest that the role of physiological color change in thermoregulation is achieved in T. septentrionalis by altering the arrangement of pigments and thus the amount of solar radiation absorbed and reflected. G protein-coupling system inhibits adenylate cyclase activity to transform ATP into cAMP and thereby causes rapid pigment aggregation. MCH deactivates the G proteins and thereby initiates pigment dispersion. This mechanism differs from that reported for teleost fish where MCH activates the G proteins and thereby causes pigment aggregation.

6.
Virol Sin ; 2021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33559831

RESUMO

Human respiratory syncytial virus (RSV) infection is the leading cause of lower respiratory tract illness (LRTI), and no vaccine against LRTI has proven to be safe and effective in infants. Our study assessed attenuated recombinant RSVs as vaccine candidates to prevent RSV infection in mice. The constructed recombinant plasmids harbored (5' to 3') a T7 promoter, hammerhead ribozyme, RSV Long strain antigenomic cDNA with cold-passaged (cp) mutations or cp combined with temperature-sensitive attenuated mutations from the A2 strain (A2cpts) or further combined with SH gene deletion (A2cptsΔSH), HDV ribozyme (δ), and a T7 terminator. These vectors were subsequently co-transfected with four helper plasmids encoding N, P, L, and M2-1 viral proteins into BHK/T7-9 cells, and the recovered viruses were then passaged in Vero cells. The rescued recombinant RSVs (rRSVs) were named rRSV-Long/A2cp, rRSV-Long/A2cpts, and rRSV-Long/A2cptsΔSH, respectively, and stably passaged in vitro, without reversion to wild type (wt) at sites containing introduced mutations or deletion. Although rRSV-Long/A2cpts and rRSV-Long/A2cptsΔSH displayed  temperature-sensitive (ts) phenotype in vitro and in vivo, all rRSVs were significantly attenuated in vivo. Furthermore, BALB/c mice immunized with rRSVs produced Th1-biased immune response, resisted wtRSV infection, and were free from enhanced respiratory disease. We showed that the combination of ΔSH with attenuation (att) mutations of cpts contributed to improving att phenotype, efficacy, and gene stability of rRSV. By successfully introducing att mutations and SH gene deletion into the RSV Long parent and producing three rRSV strains, we have laid an important foundation for the development of RSV live attenuated vaccines.

7.
Artigo em Inglês | MEDLINE | ID: mdl-33492596

RESUMO

The increase of affected river reaches by reservoirs has drastically disturbed the original hydrological conditions, and subsequently influenced the nutrient biogeochemistry in the aquatic system, particularly in the cascade reservoir system. To understand the seasonal variation of nitrogen (N) behaviors in cascade reservoirs, hydrochemistry and nitrate dual isotopes (δ15N-NO3- and δ18O-NO3-) were conducted in a karst watershed (Wujiang River) in southwest China. The results showed that NO3--N accounted for almost 90% of the total dissolved nitrogen (TDN) concentration with high average concentration 3.8 ± 0.4 mg/L among four cascade reservoirs. Higher N concentration (4.0 ± 0.8 mg/L) and larger longitudinal variation were observed in summer than in other seasons. The relationship between the variation of NO3--N and dual isotopes in the profiles demonstrated that nitrification was dominated transformation, while assimilation contributed significantly in the epilimnion during spring and summer. The high dissolved oxygen concentration in the present cascade reservoirs system prevented the occurrence of N depletion processes in most of the reservoirs. Denitrification occurred in the oldest reservoir during winter with a rate ranging from 18 to 28%. The long-term record of surface water TDN concentration in reservoirs demonstrated an increase from 2.0 to 3.6 mg/L during the past two decades (~ 0.1 mg/L per year). The seasonal nitrate isotopic signature and continuously increased fertilizer application demonstrated that chemical fertilizer contribution significantly influenced NO3--N concentration in the karst cascade reservoirs. The research highlighted that the notable N increase in karst cascade reservoirs could influence the aquatic health in the region and further investigations were required.

8.
Subst Abuse Treat Prev Policy ; 16(1): 9, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33441176

RESUMO

BACKGROUND: Anxiety, an important factor that affects the therapeutic effect and preservation rate of methadone maintenance treatment, has a high prevalence among MMT patients. This study aims to investigate the effects of treatment status and life quality on anxiety in MMT patients. METHODS: One hundred and Seventy-seven methadone maintenance treatment users in Guangzhou, China were evaluated. The socio-demographic, duration and MMT-related characteristics were documented. Anxiety level and quality of life were evaluated by Beck Anxiety inventory (BAI) and the Quality of Life-Drug Addiction (QOL-DA) respectively. The correlation between different factors and BAI score was also analyzed. RESULTS: The BAI total score and the QOL-DA score were 7.1±8.2, 163.5±21.4 respectively. 30.5% of the subjects showed mild to severe anxiety. Treatment interruption and QOL-DA score had strong correlations with the score of BAI, with correlation coefficients of 0.17 and - 0.08 respectively. CONCLUSIONS: Anxiety symptoms were commonly presented in MMT patients. Treatment interruption and quality of life are two major factors affecting anxiety of MMT patients.

9.
J Clin Anesth ; 69: 110150, 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33418429

RESUMO

STUDY OBJECTIVE: This study aimed to evaluate the effects of low versus high mean arterial pressure (MAP) levels on the incidence of postoperative delirium during non-cardiothoracic surgery in older patients. DESIGN: Multicenter, randomized, parallel-controlled, open-label, and assessor-blinded clinical trial. SETTING: University hospital. PATIENTS: Three hundred twenty-two patients aged ≥65 with an American Society of Anesthesiologists physical status of I-II who underwent non-cardiothoracic surgery with general anaesthesia. INTERVENTIONS: Participants were randomly assigned into a low-level MAP (60-70 mmHg) or high-level MAP (90-100 mmHg) group during general anaesthesia. The study was conducted from November 2016 to February 2020. Participants were older patients having non-cardiothoracic surgery. The follow-up period ranged from 1 to 7 days after surgery. The primary outcome was the incidence of postoperative delirium. MAIN RESULTS: In total, 322 patients were included and randomized; 298 completed in-hospital delirium assessments [median (interquartile range) age, 73 (68-77) years; 173 (58.1%) women]. Fifty-four (18.1%) patients total, including 36 (24.5%) and 18 (11.9%) in the low-level and high-level MAP groups [relative risk (RR) 0.48, 95% confidence interval (CI) 0.25 to 0.87, P = 0.02], respectively, experienced postoperative delirium. The adjusted RR was 0.34 (95% CI 0.16 to 0.70, P < 0.01) in the multiple regression analysis. High-level MAP was associated with a shorter delirium span and a higher intraoperative urine volume than low-level MAP. CONCLUSIONS: In older patients during non-cardiothoracic surgery, high-level blood pressure management might help reduce the incidence of postoperative delirium.

10.
BMC Microbiol ; 21(1): 7, 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33407119

RESUMO

BACKGROUND: Working in an underground tunnel environment is unavoidable in professions such as miners and tunnel workers, and there is a concern about the health of these workers. Few studies have addressed alterations in the intestinal microbiome of workers within that environment. RESULTS: Fecal samples were collected from the workers before they entered the tunnel (baseline status, BS) and after they left the tunnel (exposed status, ES), respectively (a time period of 3 weeks between them). We analyzed 16S rRNA sequencing to show the changes in microbial composition and self-evaluation of mental health questionnaire was also performed. The results showed that Shannon and Simpson indices decreased significantly from BS to ES. A higher abundance was found in the phylum Actinobacteria, classes Actinobacteria and Deltaproteobacteria, orders Bifidobacteriales, Coriobacteriales, and Desulfovibrionales, families Bifidobacteriaceae, Peptostreptococcaceae, Coriobacteriaceae, Clostridiaceae_1, Desulfovibrionaceae, Pseudomonadaceae, and Microbacteriaceae, and genera Bifidobacterium, Romboutsia, Clostridium sensu stricto, and Leucobacter in ES, while BS showed greater levels of genera Faecalibacterium and Roseburia. The self-evaluation showed that at least one-half of the tunnel workers experienced one or more symptoms of mental distress (inattention, sleeplessness, loss of appetite, headache or dizziness, irritability) after working in the underground tunnel environment. CONCLUSIONS: Collectively, the underground tunnel environment led to alterations in the intestinal microbiome, which might be relevant to symptoms of mental distress in underground-tunnel workers.

11.
Syst Rev ; 10(1): 31, 2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-33461611

RESUMO

PURPOSE: To review and summarize the clinical features, diagnosis, treatment strategies, and prognosis of spinal Rosai-Dorfman disease (RDD). METHODS: RDD is also termed as sinus histiocytosis with massive lymphadenopathy. We searched the databases of PubMed, Elsevier ScienceDirect, SpringerLink, and OVID. The keywords were Rosai-Dorfman disease and spine/central nervous system. Research articles and case reports with accessibility to full texts regarding spinal RDD were eligible for the inclusion. A total of 62 articles were included, and they contained 69 cases. We extracted the information of interest and analyzed them using SPSS statistics package. RESULTS: The average age was 33.1 ± 18.3 years. The ratio of males to females was 1.9/1. Overall, 63 cases presented with spine-related symptoms. A total of 27 cases (39.1%) had multi-organ lesions, and 12 cases had records of massive lymphadenopathy. Among 47 cases who first manifested spine-related symptoms, 93.6% were preoperatively misdiagnosed. The disease had a predilection for cervical spine (38.8%) and thoracic spine (40.3%). 62.9% of lesions were dura-based. Surgery remained the mainstream treatment option (78.8%), with or without adjuvant therapies. Total lesion resection was achieved in 34.8% of cases. The rate of lesion recurrence/progression was 19.5%, which was marginally lower for total resection than for non-total resection. CONCLUSION: Spinal RDD has no pathognomonic clinical and imaging features. Most cases first present with spine-relevant symptoms. Massive lymphadenopathy is not common, but a tendency for multi-organ involvement should be considered. Spinal RDD has a high recurrence rate; thus, total resection is the treatment of choice. Adjuvant therapies are indicated for multi-organ lesions and residual lesions. A wait and watch strategy is recommended for asymptomatic patients. Herein, a workflow of diagnosis and treatment of the spinal RDD is established.

12.
Artigo em Inglês | MEDLINE | ID: mdl-33292128

RESUMO

BACKGROUND: Osteoarthritis (OA) is a kind of chronic joint destructive disease, which seriously endangers the activity ability of the elderly all over the world and can lead to disability. However, the pathogenesis of OA is still unclear, which leads to the limited treatment and the therapeutic effect far from people's expectations. This study aims to filter out key genes in the pathogenesis of OA and explore their potential role in the occurrence and development of OA. METHOD: The dataset of GSE117999 was obtained and analyzed in order to identify the differentially expressed genes (DEGs), hub genes and key genes. We also identified potential miRNAs which may play a major role in the pathogenesis of OA, and verified their difference in OA by real-time quantitative PCR (RT-qPCR). DGldb was served to identify drugs with potential therapeutic effects on key genes and Receiver Operating Characteristic (ROC) analysis was used for identifying underlying biomarkers of OA. RESULTS: We identified ten key genes including MDM2, RB1, EGFR, ESR1, UBE2E3, WWP1, BCL2, OAS2, TYMS and MSH2. Then, we identified hsa-mir-3613-3p, hsa-mir-548e-5p and hsa-mir-5692a were potentially related to key genes. In addition, RT-qPCR confirmed the differential expression of identified genes in mouse cartilage with or without OA. We then identified Etoposide and Everolimus, were potentially specific to the most key genes. Finally, we speculated that ESR1 might be a potential biomarker of OA. CONCLUSIONS: In this study, potential key genes related to OA and their biological functions were identified, and their potential application value in the diagnosis and treatment of OA has been demonstrated , which will help us to improve the therapeutic effect of OA.

13.
Artigo em Inglês | MEDLINE | ID: mdl-33258380

RESUMO

Anterior percutaneous endoscopic cervical discectomy (APECD) is a common treatment for cervical spondylotic radiculopathy (CSR). In this study, the effects of various channel diameters and approach angles on cervical vertebrae on postoperative outcomes in APECD surgery were explored. A finite element model of intact cervical C3-C7 was constructed and then modified to obtain six surgical models. Range of motion (ROM) and intradiscal pressure (IDP) were calculated under different conditions of flexion (Fle), extension (Ext), lateral bending, and axial rotation. During Fle and bending to the left (LB), the ROM was closer to the intact model when the angle of approach was 90°. During bending to the left (LB) and rotation to the left (LR), the ROM changed considerably (43.2%, 33.7%, respectively) where the angle of approach was 45°. As the surgical channel diameter increased, the extent of the change in ROM compared with the intact model also increased. IDP decreased by 48% and 49%, respectively, compared with the intact model at the C5-C6 segment where the angle of approach was 45° and 60° during Fle, while it changed little at 90°, by less than 10%. The IDP was increased noticeably by 117.6%, 82.1%, and 105.8%, for channel diameters of 2, 3 and 4 mm, respectively. And declined noticeably during LB and LR (LB: 27.1%, 27.1%, 38.5%; LR: 37.4%, 35.5%, 48.7%). The results demonstrated that the shorter the surgical path, the smaller surgical diameter, the less the biomechanical influence on the cervical vertebra.

14.
Artigo em Inglês | MEDLINE | ID: mdl-33331055

RESUMO

Bifunctional hydrogen electrocatalysis (hydrogen-oxidation and hydrogen-evolution reactions) in alkaline solution is desirable but challenging. Among all available electrocatalysts, Ni-based materials are the only non-precious-metal-based candidates for alkaline hydrogen oxidation, but they generally suffer from low activity. Here, we demonstrate that properly alloying Ni with Mo could significantly promote its electrocatalytic performance. Ni4 Mo alloy nanoparticles are prepared from the reduction of molybdate-intercalated Ni(OH)2 nanosheets. The final product exhibits an apparent hydrogen-oxidation activity exceeding that of the Pt benchmark and a record-high mass-specific kinetic current of 79 A g-1 at an overpotential of 50 mV. A superior hydrogen-evolution performance is also measured in alkaline solution. These experimental data are rationalized by our theoretical simulations, which show that alloying Ni with Mo significantly weakens its hydrogen adsorption, improves the hydroxyl adsorption and decreases the reaction barrier for water formation.

15.
J Clin Neurosci ; 82(Pt A): 99-104, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33317748

RESUMO

BACKGROUND AND OBJECTIVE: To develop and validate a clinical nomogram for individualized predicting hematoma expansion (HE) in patients with Intracerebral Hemorrhage (ICH). METHODS: A total of 1025 patients with ICH were retrospectively enrolled in the development cohort between 2010 and 2016. We identified and integrated significant factors for HE to build a nomogram. The model was subjected to validation with a separate cohort of 397 patients from the 2017-2019. The predictive accuracy and discriminative ability were measured by concordance index (C-index). The primary outcome was HE, defined as hematoma growth more than 6 mL or 33% increase in the volume. RESULTS: A total of 1025 patients were included for univariable analysis. HE occurred in 180 patients (17.6%). The time to initial CT (≤6h vs. >6 h; p = 0.001), NIHSS score (0-4 vs. 5-14 vs. ≥15; p = 0.031), CTA spot sign (yes vs. no vs. absent; p = 0.018), hypodensities (p = 0.000), blend sign (p = 0.005), and INR (<1.2 vs. ≥1.2; p = 0.009) were identified and entered into the nomogram. The calibration curves for probability of HE showed optimal agreement between nomogram prediction and actual observation. The C-index was 0.751. The validation cohort consisted of 397 patients and HE occurred in 78 patients (19.6%). The C-index was 0.743. CONCLUSIONS: We developed and validated a nomogram that can individually predict HE for ICH in Chinese populations. This practical prognostic nomogram may help clinicians make decision of clinical practice and design of clinical studies.

17.
Biomed Environ Sci ; 33(10): 735-744, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-33228832

RESUMO

Objective: Despite the remarkable progress in efforts to control disease spread, the nationwide elimination of hepatitis B in China is still hindered by the persistently high rate of hepatitis B virus (HBV) infection in Western China. This study aimed to evaluate the strategy of hepatitis B prevention and control in Western China and identify potential areas and strategies for improvement. Methods: Susceptible population vaccination, health education, professional training of doctors, and other prevention and control measures have been implemented in Wuwei city since 2010. Data were obtained from three representative cross-sectional serosurveys conducted in 2010, 2013, and 2015. The serum samples were subjected to enzyme-linked immunosorbent assays to detect the following seromarkers: HBV surface antigen (HBsAg), antibody against hepatitis B surface antigen (anti-HBs), and antibody against hepatitis B core antigen (anti-HBc). Estimates of variance were determined using Taylor series linearization methods. Results: The three serosurveys revealed decreases in the prevalence of HBsAg (7.19% in 2010 vs. 6.51% in 2013 vs. 5.87% in 2015) and anti-HBc positivity (43.89% vs. 32.87% vs. 28.46%) and an increase in the prevalence of anti-HBs positivity (49.07% vs. 53.66% vs. 53.72%) over time. From 2010 to 2015, the legally reported incidence of hepatitis B in Wuwei city decreased from 686.53/100,000 to 53.72/100,000. Notably, persistently high HBsAg-positive rates (above 5.40%) were observed among subjects aged 20-69 years old in the three serosurveys; the prevalence of HBsAg was above 1% among children younger than 10 years old. Furthermore, rural subjects had higher rates of HBsAg and anti-HBc positivity than their urban counterparts (6.04% vs. 4.83% and 30.26% vs. 20.35%, respectively) in 2015 but had a lower rate of anti-HBs positivity (49.68 vs. 55.18%). Multivariate regression analysis showed that age, urban and rural areas, and education level were the main factors affecting HBV infection. Conclusion: Although vaccine-based prevention and control measures reduced the rate of HBV infection in Wuwei City over time, the hepatitis B infection rate in children younger than 10 years was still higher than the national average level. Therefore, the prevention and control of mother-to-child transmission and the management of the infected should be the focus of future prevention and control work.

18.
Adv Mater ; : e2006784, 2020 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-33184955

RESUMO

Layered double hydroxides (LDHs) have been recognized as potent electrocatalysts for oxygen evolution reaction (OER), but are lacking in hydrogen evolution reaction (HER) activities due to the sluggish kinetics of water dissociation in alkaline medium. Herein, aiming to simultaneously bolster the HER and OER kinetics, a metal-organic framework (MOF) mediated topotactic transformation tactic is deployed to fabricate holey ternary CoFeNi LDHs on nickel foam, exposing polygonal mesopores with atomistic edge steps and lattice defects. The optimized catalyst requires only an external voltage of 1.49 V to afford the water splitting current density of 10 mA cm-2 apart from the superb electrolytic stability, far surpassing the benchmark Pt/C||RuO2 couple. More importantly, mechanistic investigations utilizing advanced spectroscopies in conjunction with density function theory (DFT) understandings unravel while the synergetic effect among under-coordinated metal centers lowers the energy barrier of water dissociation, Fe-doping enables further modulating the d-band density of states (DOS) of Co and Ni in favor of intermediates binding, thereby promoting the intrinsic HER activity. Operando Raman studies reveal negligible structural change of the LDHs during the HER process, whereas for OER the active sites can quickly turn into oxyhydroxides in the presence of lattice defects and under-coordinated metal centers.

19.
Artigo em Inglês | MEDLINE | ID: mdl-33202136

RESUMO

Platinum telluride (PtTe2) has garnered significant research enthusiasm owing to its unique characteristics. However, large-scale synthesis of PtTe2 toward potential photoelectric and photovoltaic application has not been explored yet. Herein, we report direct tellurization of Pt nanofilms to synthesize large-area PtTe2 films and the influence of growth conditions on the morphology of PtTe2. Electrical analysis reveals that the as-grown PtTe2 films exhibit typical semimetallic behavior, which is in agreement with the results of first-principles density functional theory (DFT) simulation. Moreover, the combination of multilayered PtTe2 and Si results in the formation of a PtTe2/Si heterojunction, exhibiting an obvious rectifying effect. Moreover, the PtTe2-based photodetector displays a broadband photoresponse to incident radiation in the range of 200-1650 nm, with the maximum photoresponse at a wavelength of ∼980 nm. The R and D* of the PtTe2-based photodetector are found to be 0.406 A W-1 and 3.62 × 1012 Jones, respectively. In addition, the external quantum efficiency is as high as 32.1%. On the other hand, the response time of τrise and τfall is estimated to be 7.51 and 36.7 µs, respectively. Finally, an image sensor composed of a 8 × 8 PtTe2-based photodetector array was fabricated, which can record five near-infrared (NIR) images under 980 nm with a satisfying resolution. The result demonstrates that the as-prepared PtTe2 material will be useful for application in NIR optoelectronics.

20.
ACS Appl Mater Interfaces ; 12(49): 54507-54516, 2020 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-33233882

RESUMO

Solar-driven photocatalytic CO2 reduction into CH4 with H2O is considered to be a promising way to alleviate the energy crisis and greenhouse effect. However, current CO2 photoreduction technologies tend to overlook the role of photooxidation half reaction as well as the effect of the protons produced by water oxidation on CH4 generation, resulting in low CO2 conversion efficiency and poor CH4 selectivity. In the present study, a series of chloride-modified Bi2WO6 nanosheets were constructed in view of chloride-assisted photocatalytic water oxidation. The results show that the CH4 yield of the synthesized sample can be enhanced up to about 10 times compared to that with no Cl- modification. Besides, the selectivity of CH4 can be regulated by the loading amount of chloride, varying from 51.29% for Bi2WO6 to 94.98% for the maximum. The increase of product yield is attributed to chloride modification, which not only changed the morphology of the catalyst, but also modified the pathway of water oxidation. Further studies on intermediate products and the density functional theory calculation confirm that the Cl- ions on Bi2WO6 nanosheets not only promote H2O oxidation, but also lower the energy barrier for intermediate *CHO generation, thus facilitating CH4 production. The results gained herein may provide some illuminating insights into the design of a highly selective photocatalyst for efficient CO2 reduction.

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