RESUMO
Cancer-related cachexia is a metabolic syndrome characterized by weight loss, adipose tissue decomposition, and progressive skeletal muscle atrophy. It is a major complication of many advanced cancers and seriously affects the quality of life and survival of cancer patients. However, the specific molecules that mediate cancer-related cachexia remain elusive, and the fundamental cellular and molecular mechanisms associated with muscle atrophy and lipidolysis in cancer patients still need to be investigated. Exosomes, a newly discovered class of small extracellular vesicles that facilitate intercellular communication, have a significant role in the onset and development of various cancers. Studies have shown that exosomes play a role in the onset and progression of cancer-related cachexia by transporting active molecules such as nucleic acids and proteins. This review aimed to provide an overview of exosome developments in cancer-induced skeletal muscle atrophy and adipose tissue degradation. More importantly, exosomes were shown to have potential as diagnostic markers or therapeutic strategies for cachexia and were prospected, providing novel strategies for the diagnosis and treatment of cancer-related cachexia.
Assuntos
Caquexia , Exossomos , Neoplasias , Caquexia/etiologia , Caquexia/patologia , Caquexia/terapia , Caquexia/metabolismo , Humanos , Exossomos/metabolismo , Neoplasias/complicações , Neoplasias/patologia , Animais , Tecido Adiposo/patologia , Tecido Adiposo/metabolismo , Atrofia Muscular/patologia , Atrofia Muscular/metabolismo , Atrofia Muscular/etiologiaRESUMO
The molecular structure of the polymer PM6 is elaborately modified through random copolymerization by incorporating simple units of either difluoro-substituted thiophene (2FT) or dicyano-substituted thiophene (2CNT). The incorporation of the 2FT unit significantly enhanced the coplanarity of the random copolymers, leading to improved molecular crystallinity, whereas the introduction of the 2CNT unit featured the opposite effect. Thanks to the optimized morphology resembling a fiber-like interpenetrating network structure, the organic solar cells based on PM6-10%2FT:IT4F showed higher and more balanced charge mobilities, achieving a power conversion efficiency (PCE) of 12.65%, which is comparable to that of PM6-based devices. For comparison, the 2CN-series random copolymers-based devices exhibited lower PCEs of Ë12%. Interestingly, a superior PCE close to 19.0% is achieved in PM6:L8-BO:PM6-20%2CN based ternary device due to the significant improvement in open-circuit voltage. This work demonstrates that the crystallinity of donor polymers can be enhanced by introducing simple structural units to strengthen the coplanarity of the backbone, thereby achieving an optimized morphology that promotes favorable charge transport.
RESUMO
Achieving a more balanced charge transport by morphological control is crucial in reducing bimolecular and trap-assisted recombination and enhancing the critical parameters for efficient organic solar cells (OSCs). Hence, a facile strategy is proposed to reduce the crystallinity difference between donor and acceptor by incorporating a novel multifunctional liquid crystal small molecule (LCSM) BDTPF4-C6 into the binary blend. BDTPF4-C6 is the first LCSM based on a tetrafluorobenzene unit and features a low liquid crystal phase transition temperature and strong self-assembly ability, conducive to regulating the active layer morphology. When BDTPF4-C6 is introduced as a guest molecule into the PM6 : Y6 binary, it exhibits better compatibility with the donor PM6 and primarily resides within the PM6 phase because of the similarity-intermiscibility principle. Moreover, systematic studies revealed that BDTPF4-C6 could be used as a seeding agent for PM6 to enhance its crystallinity, thereby forming a more balanced and favourable charge transport with suppressed charge recombination. Intriguingly, dual Förster resonance energy transfer was observed between the guest molecule and the host donor and acceptor, resulting in an improved current density. This study demonstrates a facile approach to balance the charge mobilities and offers new insights into boosting the efficiency of single-junction OSCs beyond 20 %.
RESUMO
As an important neurotropic enterovirus, enterovirus 71 (EV71) is occasionally associated with severe neurological diseases and high mortality rates in infants and young children. Understanding the interaction between host factors and EV71 will play a vital role in developing antivirals and optimizing vaccines. Here, we performed a genome-wide CRISPR-Cas9 knockout screen and revealed that scavenger receptor class B member 2 (SCARB2), solute carrier family 35 member B2 (SLC35B2), and beta-1,3-glucuronyltransferase 3 (B3GAT3) are essential in facilitating EV71 replication. Subsequently, the exploration of molecular mechanisms suggested that the knockout of SLC35B2 or B3GAT3, not SCARB2, led to a remarkable decrease in the binding of EV71 to cells and internalization into cells. Furthermore, we found that the infection efficiency for EV71 was positively correlated with the level of host cell sulfation, not simply with the amount of heparan sulfate, suggesting that an unidentified sulfated protein(s) must contribute to EV71 infection. In support of this idea, we screened possible sulfated proteins among the proteinous receptors for EV71 and confirmed that SCARB2 could uniquely interact with both tyrosyl protein sulfotransferases in humans. We then performed mass spectrometric analysis of SCARB2, identifying five sites with tyrosine sulfation. The function verification test indicated that there were more than five tyrosine-sulfated sites on SCARB2. Finally, we constructed a model for EV71 entry in which both heparan sulfate and SCARB2 are regulated by SLC35B2 and act cooperatively to support viral binding, internalization, and uncoating. Taken together, this is the first time that we performed the pooled CRISPR-Cas9 genetic screening to investigate the interplay of host cells and EV71. Furthermore, we found that a novel host factor, SLC35B2, played a dual role in regulating the overall sulfation comprising heparan sulfate sulfation and protein tyrosine sulfation, which are critical for EV71 entry. IMPORTANCE As the most important nonpolio neurotropic enterovirus lacking specific treatments, EV71 can transmit to the central nervous system, leading to severe and fatal neurological complications in infants and young children. The identification of new factors that facilitate or inhibit EV71 replication is crucial to uncover the mechanisms of viral infection and pathogenesis. To date, only a few host factors involved in EV71 infection have been characterized. Herein, we conducted a genome-wide CRISPR-Cas9 functional knockout (GeCKO) screen for the first time to study EV71 in HeLa cells. The screening results are presented as a ranked list of candidates, including 518 hits in the positive selection that facilitate EV71 replication and 1,044 hits in the negative selection that may be essential for cell growth and survival or for suppressing EV71 infection. We subsequently concentrated on the top three hits in the positive selection: SCARB2, SLC35B2, and B3GAT3. The knockout of any of these three genes confers strong resistance against EV71 infection. We confirmed that EV71 infection is codependent on two receptors, heparan sulfate and SCARB2. We also identified a host entry factor, SLC35B2, indirectly facilitating EV71 infection through regulation of the host cell sulfation, and determined a novel posttranslational modification, protein tyrosine sulfation existing in SCARB2. This study revealed that EV71 infectivity exhibits a significant positive correlation with the level of cellular sulfation regulated by SLC35B2. Due to the sulfation pathway being required for many distinct viruses, including but not limited to EV71 and respiratory syncytial virus (RSV), which were tested in this study, SLC35B2 represents a target of broad-spectrum antiviral therapy.
Assuntos
Enterovirus Humano A , Infecções por Enterovirus , Transportadores de Sulfato , Enterovirus Humano A/fisiologia , Glucuronosiltransferase/genética , Glucuronosiltransferase/metabolismo , Células HeLa , Heparitina Sulfato/metabolismo , Humanos , Proteínas de Membrana Lisossomal/genética , Proteínas de Membrana Lisossomal/metabolismo , Receptores Depuradores/genética , Receptores Depuradores/metabolismo , Transportadores de Sulfato/genética , Transportadores de Sulfato/metabolismo , Sulfotransferases/metabolismo , Tirosina/metabolismoRESUMO
Esophageal carcinoma (ESCA) is one of the prevalent malignancies worldwide. Cisplatin (CDDP) is a conventional chemotherapy drug. However, the acquired cisplatin resistance limits its extensively clinical applications. In this study, the roles and underlying mechanisms of lncRNA PVT1 in cisplatin-resistant ESCA are investigated. PVT1 was significantly upregulated in ESCA patient specimens and cell lines. Higher PVT1 level was associated with a poor survival rate of ESCA patients. Silencing PVT1 effectively increased cisplatin sensitivity of ESCA cells. We established cisplatin-resistant ESCA cell line (EC109 CDDP Res) and detected that PVT1 and glutamine metabolism were remarkedly elevated in CDDP-resistant esophageal cancer cells. Bioinformatical analysis and luciferase assay illustrated that PVT1 sponged miR-181a-5p to form a ceRNA network, resulting in the downregulation of miR-181a-5p expression in ESCA cells. Glutaminase (GLS), which is a key enzyme in the glutamine metabolism, was identified and validated as a direct target of miR-181-5p in ESCA cells. Inhibiting glutamine metabolism effectively re-sensitized CDDP-resistant cells. Rescue experiments demonstrated that restoration of miR-181a-5p in PVT1-overexpressing CDDP-resistant ESCA cells successfully overcame the PVT1-promoted cisplatin resistance through targeting GLS. Summarily, our study revealed molecular mechanisms of the lncRNA PVT1-promoted cisplatin resistance in ESCA by modulating the miR-181a-5p-GLS axis.
Assuntos
Neoplasias Esofágicas , MicroRNAs , RNA Longo não Codificante , Humanos , Linhagem Celular Tumoral , Proliferação de Células , Cisplatino/farmacologia , Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Esofágicas/genética , Glutaminase/genética , Glutaminase/farmacologia , Glutamina/farmacologia , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Longo não Codificante/genéticaRESUMO
BACKGROUND: This study aimed to analyze the diagnostic value of seven autoantibodies (7-AABs) combined with carcinoembryonic antigen (CEA) and carbohydrate antigen-199 (CA199) in non-small cell lung cancer (NSCLC) and provide a new method for early screening of NSCLC. METHODS: The serum levels of 7-AABs, CEA, and CA199 were determined in the NSCLC group (n = 615), benign lung disease group (n = 183), healthy control group (n = 236), and the other tumor group (n = 226). The receiver operating characteristic area under the curve (AUC) analyses were conducted to evaluate the diagnostic efficiency of 7-AABs combined with CEA and CA199 in NSCLC. RESULTS: The positive rate of 7-AABs detection was higher than that of a single antibody detection. The positive rate of the combination of 7-AABs in NSCLC group (27.8%) was significantly higher than that of the benign lung disease group (15.8%) and healthy control group (11.4%). The positive rate of MAGE A1 was higher in patients with squamous cell carcinoma than adenocarcinoma. The levels of CEA and CA199 in the NSCLC group were significantly higher than those of the healthy control group, but had no statistical differences compared with those of benign lung disease group. The sensitivity, specificity, and AUC of the 7-AABs were 27.8%, 86.6%, and 0.665, respectively. The combination of 7-AABs with CEA and CA199 increased the sensitivity to 34.8% and AUC to 0.689. CONCLUSIONS: The diagnostic efficiency was enhanced by a combination of 7-AABs, CEA, and CA199 in NSCLC, which was helpful in the screening of NSCLC.
Assuntos
Adenocarcinoma , Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Antígeno Carcinoembrionário , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Neoplasias Pulmonares/diagnóstico , Biomarcadores TumoraisRESUMO
In this work, a thiol-ene coupling reaction was employed to prepare the semi-interpenetrating polymer network AEMs. The obtained QP-1/2 membrane exhibits high hydroxide conductivity (162.5 mS cm-1 at 80 °C) with a relatively lower swelling ratio, demonstrating its mechanical strength of 42 MPa. This membrane is noteworthy for its improved alkaline stability, as the semi-interpenetrating network effectively limits the attack of hydroxide. Even after being treated in 2 M NaOH at 80 °C for 600 h, 82.5% of the hydroxide conductivity is maintained. The H2/O2 fuel cell with QP-1/2 membrane displays a peak power density of 521 mW cm-2. Alkaline water electrolyzers based on QP-1/2 membrane demonstrated a current density of 1460 mA cm-2 at a cell voltage of 2.00 V using NiCoFe catalysts in the anode. All the results demonstrate that a semi-interpenetrating structure is a promising way to enhance the mechanical property, ionic conductivity, and alkaline stability of AEMs for the application of alkaline fuel cells and water electrolyzers.
RESUMO
Without insight into the correlation between the structure and properties, anion exchange membranes (AEMs) for fuel cells are developed usually using the empirical trial and error method or simulation methods. Here, a virtual module compound enumeration screening (V-MCES) approach, which does not require the establishment of expensive training databases and can search the chemical space containing more than 4.2×105 candidates was proposed. The accuracy of the V-MCES model was considerably improved when the model was combined with supervised learning for the feature selection of molecular descriptors. Techniques from V-MCES, correlating the molecular structures of the AEMs with the predicted chemical stability, generated a ranking list of potential high stability AEMs. Under the guidance of V-MCES, highly stable AEMs were synthesized. With understanding of AEM structure and performance by machine learning, AEM science may enter a new era of unprecedented levels of architectural design.
RESUMO
The efficient removal of persistent organic pollutants (POPs) in natural waters is vital for human survival and sustainable development. Photocatalytic degradation is a feasible and cost-effective strategy to completely disintegrate POPs at room temperature. Herein, we develop a series of direct Z-scheme BiOIO3/AgIO3 hybrid photocatalysts via a facile deposition-precipitation method. Under natural sunlight irradiation, the light intensity of which is â¼40 mW/cm2, a considerable rate constant of 0.185 min-1 for photodecomposing 40 mg/L MO is obtained over 0.5 g/L Bi@Ag-5 composite photocatalyst powder, about 92.5 and 5.3 times higher than those of pristine AgIO3 and BiOIO3. The photoactivity of Bi@Ag-5 for photodecomposing MO under natural sunlight illumination surpasses most of the reported photocatalysts under Xe lamp illumination. After natural sunlight irradiation for 20 min, 95% of MO, 82% of phenol, 78% of 2,4-DCP, 54% of ofloxacin, and 88% of tetracycline hydrochloride can be photodecomposed over Bi@Ag-5. Relative to the commercial photocatalyst TiO2 (P25), Bi@Ag-5 exhibits greatly higher photoactivity for the treatment of MO-phenol-tetracycline hydrochloride mixture pollutants in the scale-up experiment of 500 mL of solution, decreasing COD, TOC, and chromaticity value by 52, 19, and 76%, respectively, after natural sunlight irradiation for 40 min. The photodegradation process and mechanism of MO have been systematically investigated and proposed. This work provides an archetype for designing efficient photocatalysts to remove POPs.
Assuntos
Poluentes Orgânicos Persistentes , Luz Solar , Humanos , Iluminação , Tetraciclina , Catálise , Fenóis , FenolRESUMO
BACKGROUND: The purpose of this study was to explore the detection value of seven autoantibodies (TAAbs): p53, PGP9.5, SOX2, GBU4-5, MAGE A1, CAGE, and GAGE7 and three tumor markers: CYFRA21-1, NSE, and SCCA in the diagnosis of lung cancer. METHODS: ELISA was used to detect the levels of the TAAbs, and chemiluminescence immunoassay was used to test the levels of the tumor markers. The diagnostic efficacy of the TAAbs combined with the tumor markers for lung cancer was evaluated by receiver operating characteristic (ROC) curves. RESULTS: The positive rate of the combined detection of seven TAAbs and three tumor markers in lung cancer (37.8%) was higher than that in other three groups. The positive rates of SOX2, GAGE7, MAGE A1, CAGE, CYFRA21-1, and SCCA had differences among the four groups. Compared with the benign lung disease group, only GAGE7, CYFRA21-1, and SCCA differed among the groups. The combined sensitivity of the TAAbs was 29.07% (AUC, 0.594), the combined sensitivity of all the markers was 37.76% (AUC, 0.660 [p < 0.05]), and Youden's index was 0.196. In the lung cancer group, CYFRA21-1 had a significant difference in age and sex, and SOX2, MAGE A1, CYFRA21-1, NSE, and SCCA were significantly different in pathological type and TNM. In contrast, p53 and GBU4-5 showed no significant differences in age, sex, pathological type, and TNM. CONCLUSIONS: The combined detection of seven TAAbs and three tumor markers could be useful in early diagnosis of lung cancer.
Assuntos
Biomarcadores Tumorais , Neoplasias Pulmonares , Antígenos de Neoplasias , Autoanticorpos , Humanos , Queratina-19 , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/patologia , Proteína Supressora de Tumor p53RESUMO
PURPOSE: Suicide is a major public health problem, especially in low- and middle-income countries (LMICs). However, current data on temporal trends in suicide attempts are limited. Therefore, we explored the temporal trends in suicide attempts among adolescents aged 12-15 years from 12 LMICs. METHODS: The data for this study were obtained from the Global School-based Student Health Survey (GSHS) 2009-2017, wherein the interval between two surveys in most of the participating countries was approximately 6 years. The prevalences of suicide attempts were reported as weighted prevalences and 95% confidence intervals (CIs). Pooled overall estimates were calculated using meta-analysis with a random-effects model. Linear regression was used to assess the associations of a country's GNI/capita with the prevalence and temporal variations of suicide attempts. RESULTS: The pooled prevalence of suicide attempts in the LMICs decreased significantly from 17.56% in the first survey to 13.77% in the second survey (difference = 3.65%, 95% CI = 0.35-6.95%, P = 0.03). However, significant decreasing trends were only observed in two countries (Benin and Samoa), the prevalence in the remaining countries remained relatively stable. The pooled prevalence of suicide attempts decreased significantly in boys and in the 12- to 13 year age group (difference = 3.77% and 4.44%, Both P < 0.05). In addition, the correlations of gross national income per capita with the prevalences of suicide attempts was negative but not significant (P > 0.05). CONCLUSIONS: Our findings reveal a decreasing trend in the prevalence of suicide attempts among 12-15 year-old adolescents in 12 LMICs. However, the trend varied in each country. This suggests the need for tailored suicide prevention strategies in each country to reduce suicide attempts.
Assuntos
Países em Desenvolvimento , Tentativa de Suicídio , Masculino , Adolescente , Humanos , Criança , Pobreza , Renda , Instituições Acadêmicas , Inquéritos Epidemiológicos , PrevalênciaRESUMO
BACKGROUNDS: As a regulator of cell cycle, cell division cycle-associated 5 (CDCA5) is involved in the progression of various malignant tumors. However, the potential relationship between CDCA5 and lung cancer has not been reported. METHODS: In our study, we analyzed the expression of CDCA5 in a variety of malignant tumors, performed Kaplan-Meier survival analysis of lung adenocarcinoma (LUAD), explored the potential relationship between CDCA5 expression and clinicopathological characteristics, assessed the predictive capability of at different stages of clinicopathological characteristics, revealed the enriched functions and signaling pathways among LUAD paitents with high CDCA5 expression, and investigated the correlation between PD-1, PD-L1, and CDCA5 through bioinformatics analyses. Subsequently, we performed quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting (WB) to demonstrate that CDCA5 mediates the p53-p21 pathway and regulates the cell cycle. RESULT: CDCA5 is probably involved in the occurrence and development of NSCLC, and function as a reliable biomarker for predicting the survival outcomes of patients with early stage of patients with LUAD. Furthermore, CDCA5 may be a promising indicator of immunotherapy efficacy. In addition, silencing the expression of CDCA5 significantly increased the proportion of apoptotic NSCLC cells, and caused NSCLC cells to be arrested in the G1 phase. CONSLUSION: In conclusion, CDCA5 regulated the cell cycle of NSCLC cells by mediating the p53-p21 signaling pathway, participating in the development and progression of NSCLC patients.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Adenocarcinoma de Pulmão , Carcinoma Pulmonar de Células não Pequenas , Proteínas de Ciclo Celular , Neoplasias Pulmonares , Proteínas Adaptadoras de Transdução de Sinal/genética , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/patologia , Apoptose/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Ciclo Celular/genética , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Proliferação de Células , Fase G1 , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Oncogenes , Transdução de Sinais/genética , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
BACKGROUND: As an important non-apoptotic cell death method, oncosis has been reported to be closely associated with tumors in recent years. However, few research reported the relationship between oncosis and lung cancer. METHODS: In this study, we established an oncosis-based algorithm comprised of cluster grouping and a risk assessment model to predict the survival outcomes and related tumor immunity of patients with lung adenocarcinomas (LUAD). We selected 11 oncosis-related lncRNAs associated with the prognosis (CARD8-AS1, LINC00941, LINC01137, LINC01116, AC010980.2, LINC00324, AL365203.2, AL606489.1, AC004687.1, HLA-DQB1-AS1, and AL590226.1) to divide the LUAD patients into different clusters and different risk groups. Compared with patients in clsuter1, patients in cluster2 had a survival advantage and had a relatively more active tumor immunity. Subsequently, we constructed a risk assessment model to distinguish between patients into different risk groups, in which low-risk patients tend to have a better prognosis. GO enrichment analysis revealed that the risk assessment model was closely related to immune activities. In addition, low-risk patients tended to have a higher content of immune cells and stromal cells in tumor microenvironment, higher expression of PD-1, CTLA-4, HAVCR2, and were more sensitive to immune checkpoint inhibitors (ICIs), including PD-1/CTLA-4 inhibitors. The risk score had a significantly positive correlation with tumor mutation burden (TMB). The survival curve of the novel oncosis-based algorithm suggested that low-risk patients in cluster2 have the most obvious survival advantage. CONCLUSION: The novel oncosis-based algorithm investigated the prognosis and the related tumor immunity of patients with LUAD, which could provide theoretical support for customized individual treatment for LUAD patients.
Assuntos
Adenocarcinoma , Neoplasias Pulmonares , RNA Longo não Codificante , Algoritmos , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Humanos , Pulmão/metabolismo , Proteínas de Neoplasias/metabolismo , Prognóstico , Receptor de Morte Celular Programada 1 , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Medição de Risco , Microambiente Tumoral/genéticaRESUMO
OBJECTIVE: We aimed to establish an easy-to-use screening questionnaire with risk factors and suspected symptoms of COPD for primary health care settings. METHODS: Based on a nationwide epidemiological study of pulmonary health among adults in mainland China (China Pulmonary Health, CPH study) between 2012 and 2015, participants ≥40 years who completed the questionnaire and spirometry tests were recruited and randomly divided into development set and validation set by the ratio of 2:1. Parameters including sex, age, BMI, residence, education, smoking status, smoking pack-years, biomass exposure, parental history of respiratory diseases and daily respiratory symptoms were initially selected for the development of scoring system. Receiver operating characteristic (ROC) curve, area under curve (AUC), positive and negative predictive values were calculated in development set and validation set. RESULTS: After random split by 2:1 ratio, 22443 individuals were assigned to development set and 11221 to validation set. Ten variables were significantly associated with COPD independently in development set after a stepwise selection by multivariable logistic model and used to develop scoring system. The scoring system yielded good discrimination, as measured by AUC of 0.7737, and in the validation set, the AUC was 0.7711. When applying a cutoff point of ≥16, the sensitivity in development set was 0.69 (0.67 - 0.71); specificity 0.72 (0.71 - 0.73), PPV 0.25 (0.24 - 0.26) and NPV 0.94 (0.94 - 0.95). CONCLUSION: We developed and validated a comprehensive screening questionnaire, COPD-CPHS, with good discrimination. The score system still needs to be validated by large cohort in the future.Supplemental data for this article is available online at https://doi.org/10.1080/15412555.2022.2042504 .
Assuntos
Doença Pulmonar Obstrutiva Crônica , Adulto , Área Sob a Curva , China/epidemiologia , Estudos Epidemiológicos , Humanos , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Curva ROC , Espirometria , Inquéritos e QuestionáriosRESUMO
Constructing direct Z-scheme system is a promising strategy to boost the photocatalytic performance for pollution waters restoration, but it is of great challenge because of the requirement of appropriately staggered energy band alignment and intimate interfacial interaction between semiconductors. Herein, a class of core-shell structured Ag2S-AgIO3 Z-scheme heterostructure photocatalysts are designed and developed. Ag2S is generated by the in-situ ion exchange reaction and anchored on the surface of AgIO3, so the intimate interface between AgIO3 and Ag2S is realized. Integration of AgIO3 and Ag2S extends the ultraviolet absorption of AgIO3 to Vis-NIR region, and also promote the charge separation and migration efficiency, contributing to the enhanced photocatalysis activity for composite catalysts. The optimal Ag2S-AgIO4-4 catalyst exhibits a MO photo-degradation rate constant of 0.298 h-1, which reaches 5.77 and 11.4-folds higher than that of AgIO3 (0.044 h-1) and Ag2S (0.024 h-1). The as-obtained composite catalyst exhibits universally photocatalytic activity in disintegrating diverse industrial pollutants and pharmaceuticals. Particularly, driven by natural sunlight, the Ag2S-AgIO4-4 can effectively decompose MO. A plausible Z-scheme photocatalytic mechanism and reaction pathways of MO degradation over composite catalyst are systemically investigated and proposed.
Assuntos
Poluentes Ambientais , Catálise , Luz , Luz SolarRESUMO
The structural diversity of three-dimensional (3D) covalent organic frameworks (COFs) are limited as there are only a few choices of building units with multiple symmetrically distributed connection sites. To date, 4 and 6-connected stereoscopic nodes with Td , D3h , D3d and C3 symmetries have been mostly reported, delivering limited 3D topologies. We propose an efficient approach to expand the 3D COF repertoire by introducing a high-valency quadrangular prism (D4h ) stereoscopic node with a connectivity of eight, based on which two isoreticular 3D imine-linked COFs can be created. Low-dose electron microscopy allows the direct visualization of their 2-fold interpenetrated bcu networks. These 3D COFs are endowed with unique pore architectures and strong molecular binding sites, and exhibit excellent performance in separating C2 H2 /CO2 and C2 H2 /CH4 gas pairs. The introduction of high-valency stereoscopic nodes would lead to an outburst of new topologies for 3D COFs.
RESUMO
Developing highly efficient semiconductor photocatalysts for H2 evolution is intriguing, but their efficiency is subjected to the following three critical issues: limited light absorption, low carrier separation efficiency, and sluggish H2 evolution kinetics. Element surface doping is a feasible strategy to synchronously break through the above limitations. In this study, we prepared a series of Co-surface-doped ZnS photocatalysts to systematically investigate the effects of Co surface doping on photocatalytic activity and electronic structure. The implantation of Co results in the emergence of the impurity level above the valence band (VB) and the upshifted conduction band (CB) and enhances its visible light absorption. Co gradient doping inhibits the combination and facilitates the migration of carriers. S atoms are proven to be reactive active sites for photocatalytic H2 evolution over both ZnS and Co-doped ZnS. Co doping alters the surface electronic structure and decreases the absolute value for the hydrogen binding free energy (ΔGH) of the adsorbed hydrogen atom on the catalyst. As a consequence, Co-surface-doped ZnS shows boosted photocatalytic H2 evolution activity relative to the undoped material. This work provides insights into the mechanistic understanding of the surface element doping modification strategy to developing efficient photocatalysts.
RESUMO
An efficient organophosphorus-mediated cross-Rauhut-Currier/Wittig domino reaction of vinyl ketones with chalcones has been developed for the synthesis of trisubstituted cyclopentenes. The new synthetic method has the advantages of mild reaction conditions, high efficiency, environmental friendliness and satisfactory yields.
RESUMO
To explore a simple and efficient way to fabricate thin film electrodes on flexible substrates is highly desired because of its high promising application in optoelectronics. Transfer printing technique plays a key role in the fabrication of flexible electrodes from conventional substrates to flexible substrates. Unfortunately, a simple, room temperature, environmental-friendly and reusable transfer printing technique still remains challenging. Here we demonstrated a novel water-based wet-transfer printing technique that is simple, room temperature, environmental-friendly and reusable by taking advantage of the adjustment of the intermolecular hydrogen bonding between thin film and substrates. This effective and practical transfer technique may provide an effective route to develop electronic flexible devices with high performance.
RESUMO
AIM: Levels of American Heart Association-defined cardiovascular (CV) health behaviours have not been fully reported among young adolescents in low- and middle-income countries (LMICs). We describe poor, intermediate and ideal levels of American Heart Association-defined CV health behaviours among young adolescents in LMICs. METHODS: We categorised the levels of CV health behaviours (smoking, body mass index, physical activity and diet) as poor, intermediate, or ideal and calculated the prevalence of each level and the cumulative number of ideal CV health behaviours using the latest data from the global school-based health survey during 2009-2015. The weighted prevalence and 95% confidential intervals were calculated for the whole sample and for sub-groups stratified by gender and age. Pooled overall and regional estimates were calculated using a random-effects model. This study included 153 759 young adolescents from 45 countries. RESULTS: Overall, 86.3% (95% confidence interval, 82.7-89.9), 80.1% (79.8-80.4), 15.4% (13.7-17.2) and 1.7% (1.1-2.2) of respondents reported ideal levels for smoking, body mass index, physical activity and a healthy diet score, respectively. Overall, 0.3% (0.2-0.4) of respondents had 'four' cumulative ideal CV health behaviours. This 'percentage' was lowest in the Americas (0.2%) and highest in Southeast Asia (0.5%). CONCLUSIONS: Consistently low proportions of young adolescents in LMICs met the ideal levels of physical activity and a healthy diet score or had 'four' ideal CV health behaviours. For this population, physical activity and a healthy dietary pattern should be strongly prioritised.