Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 69
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Small ; : e2310368, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38511564

RESUMO

Grain boundaries (GBs) have a significant role in polycrystalline perovskite solar cells (PSCs). However, there is ongoing debate regarding the impact of GBs on the performance and long-term stability of PSCs. Employing the first-principles molecular dynamics for perovskites, the iodine vacancy defect migrations both in bulk and at GBs are investigated. i) The positive iodine vacancy (VI +) is found that have both lower formation energy (1.4 eV) and activation energy (0.18 eV) than those of neutral iodine vacancy (VI), statistically. It indicated the VI + acts as the dominant migrated iodine vacancy rather than VI; ii) the iodine vacancy at GBs has ≈0.48 eV higher activation energy than those in bulk, which leads to the accumulation of iodine vacancy at GBs; iii) the presence of VI + result in a 3-fold increase in charge recombination ratio at GBs, compared to pristine PSCs. Based on quantum molecular dynamics statistical results, which are consistent with experimental measurements, insights into iodine vacancy migration both at GBs and in the bulk are gained. This understanding can be valuable for defects engineering related to ion migration, in order to improve the long-term stability and promote the performance of PSCs.

2.
Cancer Control ; 31: 10732748241255212, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38769789

RESUMO

OBJECTIVE: A high number of Non-Small Cell Lung Cancer (NSCLC) patients with brain metastasis who have not had surgery often have a negative outlook. Radiotherapy remains a most common and effective method. Nomograms were developed to forecast the cancer-specific survival (CSS) and overall survival (OS) in NSCLC individuals with nonoperative brain metastases who underwent radiotherapy. METHODS: Information was gathered from the Surveillance, Epidemiology, and End Results (SEER) database about patients diagnosed with NSCLC who had brain metastases not suitable for surgery. Nomograms were created and tested using multivariate Cox regression models to forecast CSS and OS at intervals of 1, 2, and 3 years. RESULTS: The research involved 3413 individuals diagnosed with NSCLC brain metastases who had undergone radiotherapy but had not experienced surgery. These participants were randomly divided into two categories. The analysis revealed that gender, age, ethnicity, marital status, tumor location, tumor laterality, tumor grade, histology, T stage, N stage, chemotherapy, tumor size, lung metastasis, bone metastasis, and liver metastasis were significant independent predictors for OS and CSS. The C-index for the training set for predicting OS was .709 (95% CI, .697-.721), and for the validation set, it was .705 (95% CI, .686-.723), respectively. The C-index for predicting CSS was .710 (95% CI, .697-.722) in the training set and .703 (95% CI, .684-.722) in the validation set, respectively. The nomograms model, as suggested by the impressive C-index, exhibits outstanding differentiation ability. Moreover, the ROC and calibration curves reveal its commendable precision and distinguishing potential. CONCLUSIONS: For the first time, highly accurate and reliable nomograms were developed to predict OS and CSS in NSCLC patients with non-surgical brain metastases, who have undergone radiotherapy treatment. The nomograms may assist in tailoring counseling strategies and choosing the most effective treatment method.


Assuntos
Neoplasias Encefálicas , Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Nomogramas , Programa de SEER , Humanos , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Masculino , Feminino , Neoplasias Encefálicas/secundário , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/mortalidade , Neoplasias Pulmonares/radioterapia , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/mortalidade , Pessoa de Meia-Idade , Idoso , Prognóstico , Adulto
3.
Nucleic Acids Res ; 50(D1): D371-D379, 2022 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-34761274

RESUMO

Previous studies on enhancers and their target genes were largely based on bulk samples that represent 'average' regulatory activities from a large population of millions of cells, masking the heterogeneity and important effects from the sub-populations. In recent years, single-cell sequencing technology has enabled the profiling of open chromatin accessibility at the single-cell level (scATAC-seq), which can be used to annotate the enhancers and promoters in specific cell types. A comprehensive resource is highly desirable for exploring how the enhancers regulate the target genes at the single-cell level. Hence, we designed a single-cell database scEnhancer (http://enhanceratlas.net/scenhancer/), covering 14 527 776 enhancers and 63 658 600 enhancer-gene interactions from 1 196 906 single cells across 775 tissue/cell types in three species. An unsupervised learning method was employed to sort and combine tens or hundreds of single cells in each tissue/cell type to obtain the consensus enhancers. In addition, we utilized a cis-regulatory network algorithm to identify the enhancer-gene connections. Finally, we provided a user-friendly platform with seven useful modules to search, visualize, and browse the enhancers/genes. This database will facilitate the research community towards a functional analysis of enhancers at the single-cell level.


Assuntos
Bases de Dados Genéticas , Elementos Facilitadores Genéticos , Análise de Célula Única/métodos , Software , Aprendizado de Máquina não Supervisionado , Animais , Linhagem da Célula/genética , Cromatina/química , Cromatina/metabolismo , Sequência Consenso , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Células Eucarióticas/citologia , Células Eucarióticas/metabolismo , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Heterogeneidade Genética , Humanos , Internet , Camundongos , Anotação de Sequência Molecular , Especificidade de Órgãos , Regiões Promotoras Genéticas
4.
Angew Chem Int Ed Engl ; 63(1): e202315167, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-37983657

RESUMO

Mixed-matrix membranes (MMMs) have the potential for energy-efficient gas separation by matching the superior mass transfer and anti-plasticization properties of the fillers with processability and scaling up features of the polymers. However, construction of high-performance MMMs has been prohibited due to low filler-loading and the existence of interfacial defects. Here, high MOF-loaded, i.e., 55 wt %, MMMs are developed by a 'dormancy and double-activation' (DDA) strategy. High MOF precursor concentration suppresses crystallization in the membrane casting solution, realizing molecular level mixing of all components. Then, the polymeric matrix was formed with uniform encapsulation of MOF nutrients. Subsequently, double-activation was employed to induce MOF crystallization: the alkali promotes MOFs nucleation to harvest small porous nanocrystals while excessive ligands activate the metal ions to enhance the MOFs conversion. As such, quasi-semi-continuous mass transfer channels can be formed in the MMMs by the connected MOFs nanocrystals to boost the gas permeability. The optimized MMM shows significantly ameliorated CO2 permeability, i.e., 2841 Barrer, five-fold enhancement compared with pristine polymer membrane, with a good CO2 /N2 selectivity of 36. Besides, the nanosized MOFs intensify their interaction with polymer chains, endowing the MMMs with good anti-plasticization behaviour and stability, which advances practical application of MMMs in carbon capture.

5.
Small ; 19(16): e2207487, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36693783

RESUMO

Benefiting from the proton's small size and ultrahigh mobility in water, aqueous proton batteries are regarded as an attractive candidate for high-power and ultralow-temperature energy storage devices. Herein, a new-type C4 N polymer with uniform micropores and a large specific surface area is prepared by sulfuric acid-catalyzed ketone amine condensation reaction and employed as the electrode of proton batteries. Multi-walled carbon nanotubes (MWCNT) are introduced to induce the in situ growth of C4 N, and reaped significantly enhanced porosity and conductivity, and thus better both room- and low-temperature performance. When coupled with MnO2 @Carbon fiber (MnO2 @CF) cathode, MnO2 @CF//C4 N-50% MWCNT full battery shows unprecedented cycle stability with a capacity retention of 98% after 11 000 cycles at 10 A g-1 and even 100% after 70 000 cycles at 20 A g-1 . Additionally, a novel anti-freezing electrolyte (5 m H2 SO4  + 0.5 m MnSO4 ) is developed and showed a high ionic conductivity of 123.2 mS cm-1 at -70 °C. The resultant MnO2 @CF//C4 N-50% MWCNT battery delivers a specific capacity of 110.5 mAh g-1 even at -70 °C at 1 A g-1 , the highest in all reported proton batteries under the same conditions. This work is expected to offer a package solution for constructing high-performance ultralow-temperature aqueous proton batteries.

6.
Heart Fail Rev ; 2023 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-37943420

RESUMO

Cardiovascular diseases (CVDs) represent a paramount global mortality concern, and their prevalence is on a relentless ascent. Despite the effectiveness of contemporary medical interventions in mitigating CVD-related fatality rates and complications, their efficacy remains curtailed by an array of limitations. These include the suboptimal efficiency of direct cell injection and an inherent disequilibrium between the demand and availability of heart transplantations. Consequently, the imperative to formulate innovative strategies for cardiac regeneration therapy becomes unmistakable. Within this context, 3D bioprinting technology emerges as a vanguard contender, occupying a pivotal niche in the realm of tissue engineering and regenerative medicine. This state-of-the-art methodology holds the potential to fabricate intricate heart tissues endowed with multifaceted structures and functionalities, thereby engendering substantial promise. By harnessing the prowess of 3D bioprinting, it becomes plausible to synthesize functional cardiac architectures seamlessly enmeshed with the host tissue, affording a viable avenue for the restitution of infarcted domains and, by extension, mitigating the onerous yoke of CVDs. In this review, we encapsulate the myriad applications of 3D bioprinting technology in the domain of heart tissue regeneration. Furthermore, we usher in the latest advancements in printing methodologies and bioinks, culminating in an exploration of the extant challenges and the vista of possibilities inherent to a diverse array of approaches.

7.
Nitric Oxide ; 136-137: 24-32, 2023 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-37217001

RESUMO

Developing functional nitroxyl (HNO) donors play a significant role in the further exploration of endogenous HNO in biochemistry and pharmacology. In this work, two novel Piloty's acids (SBD-D1 and SBD-D2) were proposed by incorporating benzoxadiazole-based fluorophores, in order to achieve the dual-function of releasing both HNO and a fluorophore in situ. Under physiological conditions, both SBD-D1 and SBD-D2 efficiently donated HNO (t1/2 = 10.96 and 8.18 min, respectively). The stoichiometric generation of HNO was determined by both Vitamin B12 and phosphine compound trap. Interestingly, due to the different substitution groups on the aromatic ring, SBD-D1 with the chlorine showed no fluorescence emission, but SBD-D2 was strongly fluorescent due to the presence of the dimethylamine group. Specifically, the fluorescent signal would decrease during the release process of HNO. Moreover, theoretical calculations were performed to understand the emission difference. A strong radiation derived from benzoxadiazole with dimethylamine group due to the large transition dipole moment (∼4.3 Debye), while the presence of intramolecular charge transfer process in the donor with chlorine group caused a small transition dipole moment (<0.1 Debye). Finally, these studies would contribute to the future design and application of novel functional HNO donors for the exploration of HNO biochemistry and pharmacology.


Assuntos
Cloro , Óxidos de Nitrogênio , Óxidos de Nitrogênio/química , Ácidos Hidroxâmicos/química , Corantes Fluorescentes
8.
Int J Colorectal Dis ; 37(8): 1785-1797, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35796872

RESUMO

BACKGROUND: The rate of second primary malignancies (SPM) is gradually increasing. Yet, the risk of death from primary cancer vs. SPM is still not well understood. In this study, we investigated the survival of patients with colorectal cancer (as SPM) who had cancer in the past (prior cancer) and the risk factors of SPM death in this population. MATERIALS AND METHODS: Based on the Surveillance, Epidemiology, and End Results (SEER) database, we identified 1866 colon cancer patients with prior cancer in our main cohort and 43,959 colon cancer patients, including 37,440 patients with colon cancer as only malignancy and 6519 patients with colon cancer as subsequent colon cancer (SCC), in a second cohort and 3429 colon cancer patients, including 2371 patients with prior colon cancer (PCC) and 1058 patients with colon cancer as SPM, in a third cohort. After propensity score matching, 6519 pairs of subjects were identified in second cohort. RESULTS: Patients with prior prostate and breast cancer had a higher risk of developing colon cancer compared to those with gastrointestinal cancer. Also, colon cancer patients with different prior cancer had different survival rates. Furthermore, except for prior lung cancer (52.78 vs. 25.93%), most subjects died due to colon cancer complications. The ratio of colon cancer deaths to prior cancer deaths in patients with a low stage and high stage was 1.51 and 6.64, respectively. In addition, colon cancer-specific survival (CSS) and OS rates were significantly lower in subjects with colon cancer as the SPM than in those with PCC. Also, compared with PCC, SPM was associated with OS and CSS with HR 1.59 (95 CI 1.43-1.78) and HR 2.00 (95% CI 1.70-2.36). Furthermore, compared with only colon cancer, SCC was associated with OS and CSS with HR 1.23 (95 CI 1.17-1.29) and HR 1.13 (95% CI 1.06-1.21). CONCLUSIONS: Prior cancer was found to have an adverse impact on OS in patients with colon cancer (secondary cancer), most of whom died due to colon cancer as secondary cancer itself rather than prior cancer. Early detection and treatment strategies should be investigated in this population.


Assuntos
Neoplasias do Colo , Segunda Neoplasia Primária , Neoplasias do Colo/patologia , Humanos , Masculino , Segunda Neoplasia Primária/epidemiologia , Pontuação de Propensão , Programa de SEER
9.
Int J Cancer ; 149(7): 1435-1447, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34019699

RESUMO

Although excess adiposity has been linked with various cancers, association between body composition and some cancers remains unclear, like lung and prostate cancers. We investigated associations of body composition with risk of overall cancer and major site-specific cancers in a prospective cohort of 454 079 cancer-free participants from UK-Biobank. Body composition was measured with bioimpedance analysis. We evaluated hazard ratio (HR) and 95% confidence interval (CI) with multivariate Cox linear and nonlinear models in men and women separately. We identified 27 794 cancers over 7.6 years of follow-up. Multivariable adjusted models including fat-free mass (FFM) and fat mass (FM) showed that FFM was positively associated with overall cancer risk in men and women (HR 1.03, 95% CI 1.01-1.04 and 1.07, 1.04-1.10, respectively); while the association between FM and overall cancer disappeared after adjusting for FFM. FFM was associated with higher risks of obesity-related cancers combined, stomach (women only), malignant melanoma, postmenopausal breast, corpus uteri, prostate, kidney (men only), and blood cancers and lower risk of lung cancer. FM was associated with higher risks of obesity-related cancers combined, esophageal, colon, lung (men only), postmenopausal breast (at the lower end of FM range), and corpus uteri cancers and lower risks of rectal, malignant melanoma (women only), prostate and blood cancers. FFM and FM seemed to have different effects on cancer risk, and the effects varied substantially by cancer type, in both direction and size. Higher FM/FFM ratio was also associated with some cancers risk, and might be a useful predictor of cancer risk.


Assuntos
Adiposidade , Composição Corporal , Índice de Massa Corporal , Neoplasias/classificação , Neoplasias/epidemiologia , Obesidade/fisiopatologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/patologia , Prognóstico , Estudos Prospectivos , Fatores de Risco , Reino Unido/epidemiologia
10.
Langmuir ; 36(43): 12858-12865, 2020 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-33103434

RESUMO

The interface layer is responsible for the outward migration of oxygen atoms, which subsequently leads to an adjustment in the energetic performance of nanothermite films. In this study, sandwich-structured CuO@Ni/Al and CuO@NiO/Al nanowire thermite films were successfully prepared to investigate the effects of the interface layer on the heat-release, ignition, and combustion performance. The effects of the Ni and NiO interface layers are extremely different on the heat-release performance and combustion properties of the CuO/Al nanowire thermite film. Herein, the introduced Ni layer decreased the heat release (1979.7 J/g), reactivity (Ea = 177.3 kJ/mol), and maximum pressure (2.32 MPa) compared with the CuO/Al composite. Al/Ni alloys can be formed at the interface to prevent oxygen from diffusing between CuO and Al. Moreover, the incorporation of the Ni interface layer into the CuO/Al systems results in a heat drop due to its heat-absorption capability as well as its blockage of heat transfer from the thermite reaction. The deposition of the NiO layer between CuO and Al leads to an increase in the heat release (3014.2 J/g) and a decrease in the activation energy (Ea = 178.6 kJ/mol). The NiO layer endows the CuO/Al system with a high energy-release rate and chemical reactivity. NiO can participate in a thermite reaction, which promotes the reaction of CuO/Al and induces the condensed phase.

11.
J Med Internet Res ; 22(10): e22596, 2020 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-32936776

RESUMO

BACKGROUND: Risk and crisis communication plays an essential role in public health emergency responses. The COVID-19 pandemic has triggered spontaneous and intensive media attention, which has affected people's adoption of personal preventive measures and their mental health. OBJECTIVE: The aim of this study was to investigate the associations between exposure to COVID-19-specific information and mental health (depression and sleep quality) and self-reported compliance with personal preventive measures (face mask wearing and hand sanitizing). We also tested whether these associations were moderated by thoughtful consideration of the veracity of the information to which people were exposed. METHODS: A cross-sectional, closed web-based survey was conducted among a sample of 3035 factory workers at the beginning of work resumption following the COVID-19 outbreak in Shenzhen, China. A stratified two-stage cluster sampling design was used for recruitment. Multivariate linear and logistic regression models were used for the analyses. RESULTS: The prevalence of probable moderate-to-severe depression was 170/3035 (5.6%), while that of good or excellent sleep quality was 2110/3035 (69.5%). The prevalence of self-reported consistent face mask wearing in public places was 2903/3035 (95.7%), while that of sanitizing hands every time after returning from public spaces or touching public installations was 2151/3035 (70.9%). Of the 3035 respondents, 1013 to 1638 (33.3% to 54.0%) reported >1 hour of daily exposure to COVID-19-specific information through web-based media and television. After controlling for significant background variables, higher information exposure via television and via newspapers and magazines was associated with better sleep quality and higher compliance with hand sanitizing. Higher exposure via unofficial web-based media was associated with higher compliance with hand sanitizing but was also associated with higher depressive symptoms. In contrast, higher exposure through face-to-face communication was associated with higher depressive symptoms, worse sleep quality, and lower compliance with hand sanitizing. Exposure to information about positive outcomes for patients with COVID-19, development of vaccines and effective treatments, and heroic stories about frontline health care workers were associated with both better mental health and higher compliance with preventive measures. Higher overall information exposure was associated with higher depressive symptoms among participants who were less likely to carefully consider the veracity of the information to which they were exposed; it was also associated with better sleep quality among people who reported more thoughtful consideration of information veracity. CONCLUSIONS: This study provides empirical evidence of how the amount, sources, and contents of information to which people were exposed influenced their mental health and compliance with personal preventive measures at the initial phase of work resumption in China. Thoughtful consideration of information quality was found to play an important moderating role. Our findings may inform strategic risk communication by government and public health authorities during the COVID-19 pandemic.


Assuntos
Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/psicologia , Desinfecção das Mãos , Comportamentos de Risco à Saúde , Saúde Mental/estatística & dados numéricos , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Pneumonia Viral/psicologia , Inquéritos e Questionários , Adolescente , Adulto , Betacoronavirus , COVID-19 , China/epidemiologia , Infecções por Coronavirus/epidemiologia , Estudos Transversais , Depressão/epidemiologia , Depressão/psicologia , Surtos de Doenças , Feminino , Humanos , Masculino , Pneumonia Viral/epidemiologia , SARS-CoV-2 , Autorrelato , Cooperação e Adesão ao Tratamento/psicologia , Cooperação e Adesão ao Tratamento/estatística & dados numéricos , Adulto Jovem
12.
J Med Internet Res ; 22(9): e22457, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32924947

RESUMO

BACKGROUND: Maintaining compliance with personal preventive measures is important to achieve a balance of COVID-19 pandemic control and work resumption. OBJECTIVE: The aim of this study was to investigate self-reported compliance with four personal measures to prevent COVID-19 among a sample of factory workers in Shenzhen, China, at the beginning of work resumption in China following the COVID-19 outbreak. These preventive measures included consistent wearing of face masks in public spaces (the workplace and other public settings); sanitizing hands using soap, liquid soap, or alcohol-based hand sanitizer after returning from public spaces or touching public installations and equipment; avoiding social and meal gatherings; and avoiding crowded places. METHODS: The participants were adult factory workers who had resumed work in Shenzhen, China. A stratified two-stage cluster sampling design was used. We randomly selected 14 factories that had resumed work. All full-time employees aged ≥18 years who had resumed work in these factories were invited to complete a web-based survey. Out of 4158 workers who had resumed work in these factories, 3035 (73.0%) completed the web-based survey from March 1 to 14, 2020. Multilevel logistic regression models were fitted. RESULTS: Among the 3035 participants, 2938 (96.8%) and 2996 (98.7%) reported always wearing a face mask in the workplace and in other public settings, respectively, in the past month. However, frequencies of self-reported sanitizing hands (2152/3035, 70.9%), avoiding social and meal gatherings (2225/3035, 73.3%), and avoiding crowded places (1997/3035, 65.8%) were relatively low. At the individual level, knowledge about COVID-19 (adjusted odds ratios [AORs] from 1.16, CI 1.10-1.24, to 1.29, CI 1.21-1.37), perceived risk (AORs from 0.58, CI 0.50-0.68, to 0.85, CI 0.72-0.99) and severity (AOR 1.05, CI 1.01-1.09, and AOR 1.07, CI 1.03-1.11) of COVID-19, perceived effectiveness of preventive measures by the individual (AORs from 1.05, CI 1.00-1.10, to 1.09, CI 1.04-1.13), organization (AOR 1.30, CI 1.20-1.41), and government (AORs from 1.14, CI 1.04-1.25, to 1.21, CI 1.02-1.42), perceived preparedness for a potential outbreak after work resumption (AORs from 1.10, CI 1.00-1.21, to 1.50, CI 1.36-1.64), and depressive symptoms (AORs from 0.93, CI 0.91-0.94, to 0.96, CI 0.92-0.99) were associated with self-reported compliance with at least one personal preventive measure. At the interpersonal level, exposure to COVID-19-specific information through official media channels (AOR 1.08, CI 1.04-1.11) and face-to-face communication (AOR 0.90, CI 0.83-0.98) were associated with self-reported sanitizing of hands. The number of preventive measures implemented in the workplace was positively associated with self-reported compliance with all four preventive measures (AORs from 1.30, CI 1.08-1.57, to 1.63, CI 1.45-1.84). CONCLUSIONS: Measures are needed to strengthen hand hygiene and physical distancing among factory workers to reduce transmission following work resumption. Future programs in workplaces should address these factors at multiple levels.


Assuntos
Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/prevenção & controle , Emprego/estatística & dados numéricos , Inquéritos Epidemiológicos , Controle de Infecções/estatística & dados numéricos , Saúde Ocupacional/estatística & dados numéricos , Pandemias/prevenção & controle , Pneumonia Viral/epidemiologia , Pneumonia Viral/prevenção & controle , Autorrelato , Local de Trabalho , Adulto , Betacoronavirus , COVID-19 , China/epidemiologia , Infecções por Coronavirus/transmissão , Estudos Transversais , Surtos de Doenças , Feminino , Humanos , Controle de Infecções/métodos , Masculino , Saúde Ocupacional/normas , Razão de Chances , Pneumonia Viral/transmissão , SARS-CoV-2 , Adulto Jovem
13.
Nat Mater ; 17(8): 703-709, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30013057

RESUMO

The open-circuit voltage of organic solar cells is usually lower than the values achieved in inorganic or perovskite photovoltaic devices with comparable bandgaps. Energy losses during charge separation at the donor-acceptor interface and non-radiative recombination are among the main causes of such voltage losses. Here we combine spectroscopic and quantum-chemistry approaches to identify key rules for minimizing voltage losses: (1) a low energy offset between donor and acceptor molecular states and (2) high photoluminescence yield of the low-gap material in the blend. Following these rules, we present a range of existing and new donor-acceptor systems that combine efficient photocurrent generation with electroluminescence yield up to 0.03%, leading to non-radiative voltage losses as small as 0.21 V. This study provides a rationale to explain and further improve the performance of recently demonstrated high-open-circuit-voltage organic solar cells.

14.
Nanotechnology ; 29(36): 36LT02, 2018 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-29897341

RESUMO

In this study, a new method was reported for the fabrication of the nanostructured CuO/Al thermite film on a Cu substrate. The CuO nanorod (NR) arrays grew vertically from the Cu surfaces by electrochemical anodization processes, followed by the deposition of an Al layer on the CuO NRs via magnetron sputtering to form a core/shell CuO/Al nanothermite film, whose component, structure and morphology were subsequently characterized. In addition, the energy-release characteristics of the obtained nanothermite film were investigated using thermal analyses and laser ignition tests. All evidence demonstrates that the obtained CuO/Al is of a uniform structure and has superb energy performance. Impressively, the resulting material is potentially useful in applications of functional energetic chips due to its easy integration with microelectromechanical systems (MEMS) technologies.

15.
J Environ Sci (China) ; 71: 188-196, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30195677

RESUMO

In order to understand the size distribution and the main kind of heavy metals in particulate matter on the lead and zinc smelting affected area, particulate matter (PM) and the source samples were collected in Zhuzhou, Hunan Province from December 2011 to January 2012 and the results were discussed and interpreted. Atmospheric particles were collected with different sizes by a cascade impactor. The concentrations of heavy metals in atmospheric particles of different sizes, collected from the air and from factories, were measured using an inductively coupled plasma mass spectrometry (ICP-MS). The results indicated that the average concentration of PM, chromium (Cr), arsenic (As), cadmium (Cd) and lead (Pb) in PM was 177.3 ±â€¯33.2 µg/m3, 37.3 ±â€¯8.8 ng/m3, 17.3 ±â€¯8.1 ng/m3, 4.8 ±â€¯3.1 ng/m3 and 141.6 ±â€¯49.1 ng/m3, respectively. The size distribution of PM displayed a bimodal distribution; the maximum PM size distribution was at 1.1-2.1 µm, followed by 9-10 µm. The size distribution of As, Cd and Pb in PM was similar to the distribution of the PM mass, with peaks observed at the range of 1.1-2.1 µm and 9-10 µm ranges while for Cr, only a single-mode at 4.7-5.8 µm was observed. PM (64.7%), As (72.5%), Cd (72.2%) and Pb (75.8%) were associated with the fine mode below 2.1 µm, respectively, while Cr (46.6%) was associated with the coarse mode. The size distribution characteristics, enrichment factor, correlation coefficient values, source information and the analysis of source samples showed that As, Cd and Pb in PM were the typical heavy metal in lead and zinc smelting affected areas, which originated mainly from lead and zinc smelting sources.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Metalurgia , Metais Pesados/análise , Material Particulado/análise , Chumbo/análise , Tamanho da Partícula , Zinco/análise
16.
Br J Nutr ; 117(9): 1222-1234, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28643619

RESUMO

Leucine plays an important role in promoting muscle protein synthesis and muscle remodelling. However, what percentage of leucine is appropriate in creep feed and what proteome profile alterations are caused by dietary leucine in the skeletal muscle of piglets remain elusive. In this case, we applied isobaric tags for relative and absolute quantitation to analyse the proteome profile of the longissimus dorsi muscles of weanling piglets fed a normal leucine diet (NL; 1·66 % leucine) and a high-leucine diet (HL; 2·1 % leucine). We identified 157 differentially expressed proteins between these two groups. Bioinformatics analysis of these proteins exhibited the suppression of oxidative phosphorylation and fatty acid ß-oxidation, as well as the activation of glycolysis, in the HL group. For further confirmation, we identified that SDHB, ATP5F1, ACADM and HADHB were significantly down-regulated (P<0·01, except ATP5F1, P<0·05), whereas the glycolytic enzyme pyruvate kinase was significantly up-regulated (P<0·05) in the HL group. We also show that enhanced muscle protein synthesis and the transition from slow-to-fast fibres are altered by leucine. Together, these results indicate that leucine may alter energy metabolism and promote slow-to-fast transitions in the skeletal muscle of weanling piglets.


Assuntos
Ração Animal/análise , Dieta/veterinária , Metabolismo Energético/efeitos dos fármacos , Leucina/farmacologia , Músculo Esquelético/fisiologia , Suínos/fisiologia , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Suplementos Nutricionais , Leucina/administração & dosagem , Sistema de Sinalização das MAP Quinases/fisiologia , Proteínas Proto-Oncogênicas c-jun/genética , Proteínas Proto-Oncogênicas c-jun/metabolismo
17.
J Proteome Res ; 15(4): 1262-73, 2016 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-26967195

RESUMO

Intrauterine growth restriction (IUGR) impairs fetal growth and development, perturbs nutrient metabolism, and increases the risk of developing diseases in postnatal life. However, the underlying mechanisms by which IUGR affects fetal liver development and metabolism remain incompletely understood. Here, we applied a high-throughput proteomics approach and biochemical analysis to investigate the impact of IUGR on the liver of newborn piglets. As a result, we identified 78 differentially expressed proteins in the three biological replicates, including 31 significantly up-regulated proteins and 47 significantly down-regulated proteins. Among them, a majority of differentially expressed proteins were related to nutrient metabolism and mitochondrial function. Additionally, many significantly down-regulated proteins participated in the mTOR signaling pathway and the phagosome maturation signaling pathway. Further analysis suggested that glucose concentration and hepatic glycogen storage were both reduced in IUGR newborn piglets, which may contribute to AMPK activation and mTORC1 inhibition. However, AMPK activation and mTORC1 inhibition failed to induce autophagy in the liver of IUGR neonatal pigs. A possible reason is that PP2Ac, a potential candidate in autophagy regulation, is significantly down-regulated in the liver of IUGR newborn piglets. These findings may provide implications for preventing and treating IUGR in human beings and domestic animals.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Retardo do Crescimento Fetal/genética , Hepatócitos/metabolismo , Fígado/metabolismo , Proteoma/análise , Serina-Treonina Quinases TOR/metabolismo , Proteínas Quinases Ativadas por AMP/genética , Animais , Animais Recém-Nascidos , Autofagia , Cromatografia Líquida , Retardo do Crescimento Fetal/metabolismo , Retardo do Crescimento Fetal/patologia , Regulação da Expressão Gênica no Desenvolvimento , Glucose/metabolismo , Glicogênio/metabolismo , Hepatócitos/patologia , Alvo Mecanístico do Complexo 1 de Rapamicina , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Anotação de Sequência Molecular , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Fagossomos/metabolismo , Proteína Fosfatase 2/genética , Proteína Fosfatase 2/metabolismo , Proteoma/genética , Proteoma/metabolismo , Transdução de Sinais , Suínos , Serina-Treonina Quinases TOR/genética , Espectrometria de Massas em Tandem
18.
J Am Chem Soc ; 136(49): 16954-7, 2014 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-25424459

RESUMO

We investigate the molecular structure of the solvated complex, [(NC)6Fe-Pt(NH3)4-Fe(CN)6](4-), and related dinuclear and mononuclear model complexes using first-principles calculations. Mixed nuclear complexes in both solution and crystal phases were widely studied as models for charge transfer (CT) reactions using advanced spectroscopical and electrochemical tools. In contrast to earlier interpretations, we find that the most stable gas phase and solvated geometries are substantially different from the crystal phase geometry, mainly due to variance in the underlying oxidation numbers of the metal centers. Specifically, in the crystal phase a Pt(IV) metal center resulting from Fe ← Pt backward electron transfers is stabilized by an octahedral ligand field, whereas in the solution phase a Pt(II) metal complex that prefers a square planar ligand field forms a CT salt by bridging to the iron complexes through long-range electrostatic interactions. The different geometry is shown to be consistent with spectroscopical data and measured CT rates of the solvated complex. Interestingly, we find that the experimentally indicated photoinduced process in the solvated complex is of backward CT (Fe ← Pt).


Assuntos
Compostos de Ferro/química , Nitrilas/química , Platina/química , Cinética , Estrutura Molecular , Processos Fotoquímicos , Teoria Quântica , Soluções , Espectrofotometria Infravermelho
19.
J Environ Sci (China) ; 26(1): 147-53, 2014 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-24649700

RESUMO

To understand the pollution characteristics of atmospheric particles and heavy metals in winter in Chang-Zhu-Tan city clusters, China, total suspended particulate (TSP) and PM10 samples were collected in cities of Changsha, Zhuzhou and Xiangtan from December 2011 to January 2012, and heavy metals of Cd, Pb, Cr, and As were analyzed. It shows that the average TSP concentration in Changsha, Zhuzhou and Xiangtan were (183 +/- 73), (201 +/- 84) and (190 +/- 66) microg/m3 respectively, and the average PM10 were (171 +/- 82), (178 +/- 65) and (179 +/- 55) microg/m3 respectively. The lowest TSP and PM10 concentrations occurred at the background Shaping site of Changsha. The average ratio of p(PM10)/p(TSP) was 91.9%, ranging from 81.3% to 98.9%. Concerning heavy metals, in TSP samples, the concentration of Cr, As, Cd and Pb were 28.8-56.5, 18.1-76.3, 3.9-26.1 and 148.0-460.9 ng/m3, respectively, while in PM10 samples, were 16.4-42.1, 15.5-67.9, 3.3-22.2 and 127.9-389.3 ng/m3, respectively. The enrichment factor of Cd was the highest, followed by Pb and As, while that of Cr was the lowest.


Assuntos
Poluentes Atmosféricos/análise , Metais Pesados/análise , Material Particulado/análise , China , Cidades
20.
Nat Commun ; 15(1): 3649, 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38684671

RESUMO

Two-dimensional nanofluidics based on naturally abundant clay are good candidates for harvesting osmotic energy between the sea and river from the perspective of commercialization and environmental sustainability. However, clay-based nanofluidics outputting long-term considerable osmotic power remains extremely challenging to achieve due to the lack of surface charge and mechanical strength. Here, a two-dimensional all-natural nanofluidic (2D-NNF) is developed as a robust and highly efficient osmotic energy generator based on an interlocking configuration of stacked montmorillonite nanosheets (from natural clay) and their intercalated cellulose nanofibers (from natural wood). The generated nano-confined interlamellar channels with abundant surface and space negative charges facilitate selective and fast hopping transport of cations in the 2D-NNF. This contributes to an osmotic power output of ~8.61 W m-2 by mixing artificial seawater and river water, higher than other reported state-of-the-art 2D nanofluidics. According to detailed life cycle assessments (LCA), the 2D-NNF demonstrates great advantages in resource consumption (1/14), greenhouse gas emissions (1/9), and production costs (1/13) compared with the mainstream 2D nanofluidics, promising good sustainability for large-scale and highly-efficient osmotic power generation.

SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa