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1.
Cancer Control ; 31: 10732748241258602, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38783766

RESUMO

INTRODUCTION: Brain cancer is the leading cause of cancer-related deaths in children and the majority of childhood brain tumors are diagnosed without determination of their underlying etiology. Little is known about risk factors for childhood brain tumors in Vietnam. The objective of this case-control study was to identify maternal and perinatal factors associated with brain tumors occurring in young Vietnamese children and adolescents. METHODS: We conducted a hospital-based case-control study at Viet Duc University Hospital in Hanoi, Vietnam. Cases consisted of children with brain tumors aged 0-14 years old admitted to the hospital from January 2020 to July 2022 while the controls were age and sex-matched hospitalized children diagnosed with head trauma. Perinatal characteristics were abstracted from hospital medical records and maternal medical, behavioral, and sociodemographic factors were collected through in-person interviews. Conditional logistic regression models were used to examine maternal and perinatal factors associated with childhood brain tumors. RESULTS: The study sample included 220 children (110 cases and 110 controls) whose average age was 8.9 years and 41.8% were girls. Children born to mothers aged greater than 30 years at the time of the child's birth had a higher risk of childhood brain tumors compared to those born to mothers aged from 18 to 30 years old (OR = 2.55; 95% CI: 1.13-5.75). Additionally low maternal body mass index prior to the current pregnancy of <18.5 kg/m2 significantly increased the odds of having a child with a brain tumor in relation to normal maternal body mass index from 18.5-22.9 kg/m2 (OR = 3.19; 95% CI: 1.36 - 7.50). CONCLUSION: Advanced maternal age and being markedly underweight were associated with an increased odds of having a child with a brain tumor. A population-based study with larger sample size is needed to confirm and extend the present findings.


Assuntos
Neoplasias Encefálicas , Humanos , Estudos de Casos e Controles , Feminino , Neoplasias Encefálicas/epidemiologia , Vietnã/epidemiologia , Criança , Masculino , Adolescente , Fatores de Risco , Pré-Escolar , Lactente , Adulto , Gravidez , Recém-Nascido , Adulto Jovem , Idade Materna
2.
Psychophysiology ; 61(3): e14497, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38044748

RESUMO

Electroencephalography (EEG) data processing to derive event-related potentials (ERPs) follows a standard set of procedures to maximize signal-to-noise ratio. This often includes ocular correction, which corrects for artifacts introduced by eye movements, typically measured by electrooculogram (EOG) using facial electrodes near the eyes. Yet, attaching electrodes to the face may be uncomfortable for some populations, best to avoid in some situations, and contribute to data loss. Eye movements can also be measured using electrodes in a standard 10-20 EEG cap. An examination of the impact of electrode selection on ERPs is needed to inform best practices. The present study examined data quality when using different electrodes to measure eye movements for ocular correction (i.e., facial electrodes, cap electrodes, and no ocular correction) for two well-established and widely studied ERP components (i.e., reward positivity, RewP; and late positive potential, LPP) elicited in adolescents (N = 34). Results revealed comparable split-half reliability and standardized measurement error (SME) between facial and cap electrode approaches, with lower SME for the RewP with facial or cap electrodes compared to no ocular correction. Few significant differences in mean amplitude of ERPs were observed, but the LPP to positive images differed when using facial compared to cap electrodes. Findings provide preliminary evidence of the ability to collect high-quality ERP data without facial electrodes. However, when using cap electrodes for EOG measurement and ocular correction, it is recommended to use consistent procedures across the sample or statistically examine the impact of ocular correction procedures on results.


Assuntos
Eletroencefalografia , Potenciais Evocados , Humanos , Adolescente , Reprodutibilidade dos Testes , Eletroencefalografia/métodos , Eletrodos , Recompensa
3.
Molecules ; 29(5)2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38474685

RESUMO

Microplastics (MP) encompass not only plastic products but also paint particles. Marine microdebris, including MP, was retrieved from five sampling stations spanning Nagasaki-Goto island and was classified into six types, primarily consisting of MP (A), Si-based (B), and Cu-based (C) paint particles. Type-A particles, i.e., MP, were exceedingly small, with 74% of them having a long diameter of 25 µm or less. The vertical distribution of type C, containing cuprous oxide, exhibited no depth dependence, with its dominant size being less than 7 µm. It was considered that the presence of type C was associated with a natural phenomenon of MP loss. To clarify this, polypropylene (PP) samples containing cuprous oxide were prepared, and their accelerated degradation behavior was studied using a novel enhanced degradation method employing a sulfate ion radical as an initiator. Infrared spectroscopy revealed the formation of a copper soap compound in seawater. Scanning electron microscopy/energy-dispersive X-ray spectroscopy analysis indicated that the chemical reactions between Cl- and cuprous oxide produced Cu+ ions. The acceleration of degradation induced by the copper soap formed was studied through the changes in the number of PP chain scissions, revealing that the presence of type-C accelerated MP degradation.

4.
J Clin Pediatr Dent ; 47(4): 25-34, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37408343

RESUMO

Orofacial myofunctional disorders (OMD) and sleep-disordered breathing (SDB) may present as comorbidities. Orofacial characteristics might serve as a clinical marker of SDB, allowing early identification and management of OMD and improving treatment outcomes for sleep disorders. The study aims to characterize OMD in children with SDB symptoms and to investigate possible relationships between the presence of various components of OMD and symptoms of SDB. A cross-sectional study of healthy children aged 6-8 from primary schools was conducted in central Vietnam in 2019. SDB symptoms were collected using the parental Pediatric Sleep Questionnaire, Snoring Severity Scale, Epworth Daytime Sleepiness Scale, and lip-taping nasal breathing assessment. Orofacial myofunctional evaluation included assessment of tongue mobility, as well as of lip and tongue strength using the Iowa Oral Performance Instrument, and of orofacial characteristics by the protocol of Orofacial Myofunctional Evaluation with Scores. Statistical analysis was used to investigate the relationship between OMD components and SDB symptoms. 487 healthy children were evaluated, of whom 46.2% were female. There were 7.6% of children at high risk of SDB. Children with habitual snoring (10.3%) had an increased incidence of restricted tongue mobility and decreased lip and tongue strength. Abnormal breathing patterns (22.4%) demonstrated lower posterior tongue mobility and lower muscle strength. Daytime sleepiness symptoms were associated with changes in muscle strength, facial appearance, and impaired orofacial function. Lower strengths of lip and tongue or improper nasal breathing were more likely to be present in children with reported sleep apnea (6.6%). Neurobehavioral symptoms of inattention and hyperactivity were linked to anomalous appearance/posture, increases in tongue mobility and oral strength. This study demonstrates a prevalence of orofacial myofunctional anomalies in children exhibiting SDB symptoms. Children with prominent SDB symptoms should be considered as candidates for further orofacial myofunctional assessment.


Assuntos
Distúrbios do Sono por Sonolência Excessiva , Síndromes da Apneia do Sono , Humanos , Criança , Feminino , Masculino , Ronco/diagnóstico , Ronco/epidemiologia , Estudos Transversais , Síndromes da Apneia do Sono/diagnóstico , Síndromes da Apneia do Sono/epidemiologia , Inquéritos e Questionários
5.
Environ Res ; 208: 112744, 2022 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-35065928

RESUMO

Antibiotics might build up into the human body by foodstuff metabolism, posing a serious threat to human health and safety. Establishing simple and sensitive technology for quick antibiotic evaluation is thus extremely important. Nanomaterials (or NMTs) with the advantage of possessing merits such as remarkable optical, thermal, mechanical, and electrical capabilities have been highlighted as a piece of the best promising materials for rising new paths in the creation of the future generation biosensors. This paper presents the most recent advances in the use of graphene NMTs-based biosensors to determine antibiotics. Gr-NMTs (or graphene nanomaterials) have been used in the development of a biosensor for the electrochemical signal-transducing process. The rising issues and potential chances of this field are contained to give a plan for forthcoming research orientations. As a result, this review provides a comprehensive evaluation of the nanostructured electrochemical sensing approach for antibiotic residues in various systems. In this review, various electrochemical techniques such as CV, DPV, Stripping, EIS, LSV, chronoamperometry, SWV were employed to determine antibiotics. Additionally, this also demonstrates how graphene nanomaterials are employed to detect antibiotics.


Assuntos
Técnicas Biossensoriais , Grafite , Nanoestruturas , Antibacterianos , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Grafite/química , Humanos , Nanoestruturas/química
6.
Biodegradation ; 33(3): 301-316, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35499742

RESUMO

Three different fungi were tested for their ability to degrade 2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophenoxyacetic acid and for the role of laccases and cytochromes P450-type in this process. We studied a white-rot fungus Rigidoporus sp. FMD21, which has a high laccase activity, for its efficiency to degrade these herbicides. A positive correlation was found between its laccase activity and the corresponding herbicide degradation rate. Even more, the doubling of the enzyme activity in this phase corresponded with a doubling of the herbicide degradation rate. It is, therefore, tempting to speculate that laccase is the most dominant enzyme in the degradation of 2,4-D and 2,4,5-T under these conditions. In addition, it was shown that Rigidoporus sp. FMD21 partly relies on cytochromes P450-type for the breakdown of the herbicides as well. Two filamentous fungi were isolated from soil contaminated with herbicides and dioxins located at Bien Hoa airbase. They belong to genera Fusarium and Verticillium of the phylum Ascomycota as judged by their 18S rRNA gene sequences. Both isolated fungi were able to degrade the herbicides but with different rates. Their laccase activity, however, was very low and did not correlate with the rate of breakdown of the herbicides. These data indicate that the white-rot fungus most likely synthesizes laccase and cytochromes P450-type for the breakdown of the herbicides, while the types of enzyme used for the breakdown of the herbicides by the two Ascomycota remain unclear.


Assuntos
Ácido 2,4-Diclorofenoxiacético , Herbicidas , Ácido 2,4,5-Triclorofenoxiacético/metabolismo , Ácido 2,4-Diclorofenoxiacético/metabolismo , Biodegradação Ambiental , Citocromos/metabolismo , Fungos/metabolismo , Herbicidas/metabolismo , Lacase/metabolismo , Vietnã
7.
Biomed Chromatogr ; 36(6): e5364, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35274322

RESUMO

In this paper, we discuss veterinary medicine and its applications in the food industry as well as the risk to the health of humans and animals caused by these residues. We review how the veterinary residues enter and cause some detrimental effects. We also mention two techniques to determine the residue of veterinary medications that exist in food originating from animals, including classic and advanced techniques. Finally, we discuss the potential of various developed methods and compare them with some traditional techniques.


Assuntos
Resíduos de Drogas , Drogas Veterinárias , Animais , Resíduos de Drogas/análise , Contaminação de Alimentos/análise , Drogas Veterinárias/análise
8.
Mol Ecol ; 30(23): 6273-6288, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34845798

RESUMO

Whole-genome sequencing has advanced the study of species evolution, including the detection of genealogical discordant events such as ancient hybridization and incomplete lineage sorting (ILS). The evolutionary history of bighorn (Ovis canadensis) and thinhorn (Ovis dalli) sheep present an ideal system to investigate evolutionary discordance due to their recent and rapid radiation and putative secondary contact between bighorn and thinhorn sheep subspecies, specifically the dark pelage Stone sheep (O. dalli stonei) and predominately white Dall sheep (O. dalli dalli), during the last ice age. Here, we used multiple genomes of bighorn and thinhorn sheep, together with snow (O. nivicola) and the domestic sheep (O. aries) as outgroups, to assess their phylogenomic history, potential introgression patterns and their adaptive consequences. Among the Pachyceriforms (snow, bighorn and thinhorn sheep) a consistent monophyletic species tree was retrieved; however, many genealogical discordance patterns were observed. Alternative phylogenies frequently placed Stone and bighorn as sister clades. This relationship occurred more often and was less divergent than that between Dall and bighorn. We also observed many blocks containing introgression signal between Stone and bighorn genomes in which coat colour genes were present. Introgression signals observed between Dall and bighorn were more random and less frequent, and therefore probably due to ILS or intermediary secondary contact. These results strongly suggest that Stone sheep originated from a complex series of events, characterized by multiple, ancient periods of secondary contact with bighorn sheep.


Assuntos
Doenças dos Ovinos , Carneiro da Montanha , Animais , Genoma , Hibridização Genética , Filogenia , Ovinos/genética , Carneiro da Montanha/genética
9.
BMC Public Health ; 21(1): 409, 2021 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-33637080

RESUMO

BACKGROUND: Simulation exercises can functionally validate World Health Organization (WHO) International Health Regulations (IHR 2005) core capacities. In 2018, the Vietnam Ministry of Health (MOH) conducted a full-scale exercise (FSX) in response to cases of severe viral pneumonia with subsequent laboratory confirmation for Middle East Respiratory Syndrome Coronavirus (MERS-CoV) to evaluate the country's early warning and response capabilities for high-risk events. METHODS: An exercise planning team designed a complex fictitious scenario beginning with one case of severe viral pneumonia presenting at the hospital level and developed all the materials required for the exercise. Actors, controllers and evaluators were trained. In August 2018, a 3-day exercise was conducted in Quang Ninh province and Hanoi city, with participation of public health partners at the community, district, province, regional and national levels. Immediate debriefings and an after-action review were conducted after all exercise activities. Participants assessed overall exercise design, conduction and usefulness. RESULTS: FSX findings demonstrated that the event-based surveillance component of the MOH surveillance system worked optimally at different administrative levels. Detection and reporting of signals at the community and health facility levels were appropriate. Triage, verification and risk assessment were successfully implemented to identify a high-risk event and trigger timely response. The FSX identified infection control, coordination with internal and external response partners and process documentation as response challenges. Participants positively evaluated the exercise training and design. CONCLUSIONS: This exercise documents the value of exercising surveillance capabilities as part of a real-time operational scenario before facing a true emergency. The timing of this exercise and choice of disease scenario was particularly fortuitous given the subsequent appearance of COVID-19. As a result of this exercise and subsequent improvements made by the MOH, the country may have been better able to deal with the emergence of SARS-CoV-2 and contain it.


Assuntos
Surtos de Doenças/prevenção & controle , Vigilância em Saúde Pública/métodos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/prevenção & controle , Humanos , Coronavírus da Síndrome Respiratória do Oriente Médio/isolamento & purificação , Pneumonia Viral/epidemiologia , Pneumonia Viral/prevenção & controle , Vietnã/epidemiologia , Organização Mundial da Saúde
10.
Emerg Infect Dis ; 26(3): 596-600, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32091368

RESUMO

During 2015-2018, seven schools in rural Vietnam experienced diphtheria outbreaks. Multilocus sequence types were the same within schools but differed between schools. Low vaccine coverage and crowded dormitories might have contributed to the outbreaks. Authorities should consider administering routine vaccinations and booster doses for students entering the school system.


Assuntos
Corynebacterium diphtheriae/isolamento & purificação , Difteria/epidemiologia , Surtos de Doenças , Instituições Acadêmicas , Adolescente , Criança , Serviços de Saúde da Criança , Pré-Escolar , Corynebacterium diphtheriae/genética , Demografia , Difteria/etiologia , Difteria/prevenção & controle , Feminino , Humanos , Lactente , Masculino , Tipagem de Sequências Multilocus , Vacinação , Vietnã/epidemiologia , Adulto Jovem
11.
Arch Virol ; 165(4): 823-834, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32008121

RESUMO

While conducting sentinel surveillance of hand, foot, and mouth disease (HFMD) in Vietnam, we found a sudden increase in the prevalence of coxsackievirus A10 (CV-A10) in 2016 and CV-A2 and CV-A4 in 2017, the emergence of which has been reported recently to be associated with various clinical manifestations in other countries. However, there have been only a limited number of molecular studies on those serotypes, with none being conducted in Vietnam. Therefore, we sequenced the entire VP1 genes of CV-A10, CV-A4, and CV-A2 strains associated with HFMD in Vietnam between 2012 and 2017. Phylogenetic analysis revealed a trend of endemic circulation of Vietnamese CV-A10, CV-A4, and CV-A2 strains and the emergence of thus-far undescribed HFMD-causing lineages of CV-A4 and CV-A2. The Vietnamese CV-A10 strains belonged to a genotype comprising isolates from patients with HFMD from several other countries; however, most of the Vietnamese strains were grouped into a local lineage. Recently, emerging CV-A4 strains in Vietnam were grouped into a unique lineage within a genotype comprising strains isolated from patients with acute flaccid paralysis from various countries. New substitutions were detected in the putative BC and HI loops in the Vietnamese CV-A4 strains. Except for one strain, Vietnamese CV-A2 isolates were grouped into a unique lineage of a genotype that includes strains from various countries that are associated with other clinical manifestations. Enhanced surveillance is required to monitor their spread and to specify their roles as etiological agents of HFMD or "HFMD-like" diseases, especially for CV-A4 and CV-A2. Further studies including whole-genome sequencing should be conducted to fully understand the evolutionary changes occurring in these newly emerging strains.


Assuntos
Proteínas do Capsídeo/genética , Enterovirus Humano A/isolamento & purificação , Doença de Mão, Pé e Boca/virologia , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/virologia , Surtos de Doenças , Enterovirus Humano A/classificação , Enterovirus Humano A/genética , Genoma Viral , Genótipo , Doença de Mão, Pé e Boca/epidemiologia , Humanos , Filogenia , Vigilância de Evento Sentinela , Vietnã/epidemiologia
12.
Global Health ; 16(1): 38, 2020 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-32354353

RESUMO

BACKGROUND: In 2016-2017, Vietnam's Ministry of Health (MoH) implemented an event-based surveillance (EBS) pilot project in six provinces as part of Global Health Security Agenda (GHSA) efforts. This manuscript describes development and design of tools for monitoring and evaluation (M&E) of EBS in Vietnam. METHODS: A strategic EBS framework was developed based on the EBS implementation pilot project's goals and objectives. The main process and outcome components were identified and included input, activities, outputs, and outcome indicators. M&E tools were developed to collect quantitative and qualitative data. The tools included a supervisory checklist, a desk review tool, a key informant interview guide, a focus group discussion guide, a timeliness form, and an online acceptability survey. An evaluation team conducted field visits for assessment of EBS 5-9 months after implementation. RESULTS: The quantitative data collected provided evidence on the number and type of events that were being reported, the timeliness of the system, and the event-to-signal ratio. The qualitative and subjective data collected helped to increase understanding of the system's field utility and acceptance by field staff, reasons for non-compliance with established guidelines, and other factors influencing implementation. CONCLUSIONS: The use of M&E tools for the EBS pilot project in Vietnam provided data on signals and events reported, timeliness of reporting and response, perceptions and opinions of implementers, and fidelity of EBS implementation. These data were valuable for Vietnam's MoH to understand the function of the EBS program, and the success and challenges of implementing this project in Vietnam.


Assuntos
Monitoramento Epidemiológico , Saúde Global , Surtos de Doenças , Humanos , Projetos Piloto , Inquéritos e Questionários , Vietnã
13.
Mol Cell Neurosci ; 92: 1-11, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29936143

RESUMO

E2F1 is a transcription factor classically known to regulate G0/G1 to S phase progression in the cell cycle. In addition, E2F1 also regulates a wide range of apoptotic genes and thus has been well studied in the context of neuronal death and neurodegenerative diseases. However, its function and regulation in the mature central nervous system are not well understood. Alternative splicing is a well-conserved post-transcriptional mechanism common in cells of the CNS and is necessary to generate diverse functional modifications to RNA or protein products from genes. Heretofore, physiologically significant alternatively spliced E2F1 transcripts have not been reported. In the present study, we report the identification of two novel alternatively spliced E2F1 transcripts: E2F1b, an E2F1 transcript retaining intron 5, and E2F1c, an E2F1 transcript excluding exon 6. These alternatively spliced transcripts are observed in the brain and neural cell types including neurons, astrocytes, and undifferentiated oligodendrocytes. The expression of these E2F1 transcripts is distinct during maturation of primary hippocampal neuroglial cells. Pharmacologically-induced global translation inhibition with cycloheximide, anisomycin or thapsigargin lead to significantly reduced expression of E2F1a, E2F1b and E2F1c. Conversely, increasing neuronal activity by elevating the concentration of potassium chloride selectively increased the expression of E2F1b. Furthermore, experiments expressing these variants in vitro show the transcripts can be translated to generate a protein product. Taken together, our data suggest that the alternatively spliced E2F1 transcript behave differently than the E2F1a transcript, and our results provide a foundation for future investigation of the function of E2F1 splice variants in the CNS.


Assuntos
Processamento Alternativo , Fator de Transcrição E2F1/genética , Hipocampo/metabolismo , Animais , Células Cultivadas , Fator de Transcrição E2F1/metabolismo , Hipocampo/citologia , Neuroglia/metabolismo , Neurônios/metabolismo , Ratos , Ratos Sprague-Dawley
14.
J Asian Nat Prod Res ; 21(9): 867-872, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29986612

RESUMO

From an EtOAc-soluble fraction of the leaves of Azadirachta indica, two new 28-norlimonoids named nimbandiolactone-21 (1) and nimbandioloxyfuran (2), together with nimbandiolactone-23 (3), were isolated. Their relative structures were elucidated based on NMR spectroscopic interpretation and biosynthetic consideration. Nimbandioloxyfuran (2) and nimbandiolactone-23 (3) showed potent α-glucosidase inhibitory activity, with the IC50 values of 46.2 and 38.7 µM, respectively.


Assuntos
Azadirachta/química , Limoninas/química , Folhas de Planta/química , Estrutura Molecular
15.
Emerg Infect Dis ; 24(9): 1649-1658, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30124198

RESUMO

Surveillance and outbreak reporting systems in Vietnam required improvements to function effectively as early warning and response systems. Accordingly, the Ministry of Health of Vietnam, in collaboration with the US Centers for Disease Control and Prevention, launched a pilot project in 2016 focusing on community and hospital event-based surveillance. The pilot was implemented in 4 of Vietnam's 63 provinces. The pilot demonstrated that event-based surveillance resulted in early detection and reporting of outbreaks, improved collaboration between the healthcare facilities and preventive sectors of the ministry, and increased community participation in surveillance and reporting.


Assuntos
Controle de Doenças Transmissíveis , Surtos de Doenças/prevenção & controle , Vigilância da População , Instalações de Saúde , Hospitais , Humanos , Vietnã/epidemiologia
16.
J Nanosci Nanotechnol ; 18(10): 7170-7176, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-29954554

RESUMO

In this work, the success of doping Na into Cu2O thin films by reactive DC magnetron sputtering method at low temperature is described for the first time. The characteristics of crystal structure, morphology, optical, electrical properties and binding of elements in Cu2O:Na thin films are carefully investigated. The Cu2O:Na thin films have exhibited high electronic conductivity as p-type semiconductor and absorption in visible range. The highest hole concentration on the order of 1018 cm-3 and the lowest resistivity of 6.726 Ω · cm according to 6.56% Na impurities in Cu2O:Na lattice are also detected. The role of Na impurity in Cu2O structure is proposed that based on the changing of structure and alignment of elements.

17.
J Nanosci Nanotechnol ; 17(1): 634-39, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29630318

RESUMO

The p-Cu2O/i-ZnO nanorods/n-IGZO heterojunctions were fabricated by electrochemical and sputtering method. ZnO nanorods were grown on conductive indium gallium zinc oxide (IGZO) thin film and then p-Cu2O layer was deposited on ZnO nanorods to form the heterojunction. ZnO nanorods play an important role in carrier transport mechanisms and performance of the junction. The changing of defects in ZnO nanorods by annealing samples in air and vacuum have studied. The XRD, photoluminescence (PL) spectroscopy, and FTIR were used to study about structure, and defects in ZnO nanorods. The SEM, i­V characteristics methods were also used to define structure, electrical properties of the heterojunctions layers. The results show that the defects in ZnO nanorods affected remarkably on performance of heterojunctions of solar cells.

18.
J Nanosci Nanotechnol ; 16(4): 3557-63, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27451665

RESUMO

Reduced Graphene Oxide Wrapped Pd/TiO2 (r-GO@Pd/TiO2) which exhibited high photocatalytic activity under visible light was synthesized from commercial chemicals. The classic sol-gel method and the Ar gas bubbling composition was used in the preparation of the catalyst. Furthermore, the best Pd-doping concentration in crystals, the wrapping concentration of r-GO over nanoparticles, and the optimal calcination temperature were investigated to enhance the photocatalytic activity of the hybrid catalyst. The experimental results showed that the catalytic efficiency of r-GO@Pd/TiO2 reached maximum value at the optimum synthesis conditions: 0.7 wt% Pd-doped TiO2 by sol-gel process, calcination temperature of 550 °C, 1 mg of GO for 100 .gram wrapped Pd/TiO2. X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) techniques were conducted to determine the nanostructure of the catalysts. The average crystallite size of nanoparticles was 14 nm with perfect dispersion of Pd dots and wraps of r-GO membrane. Methyl Blue was used as an organic dye model to test the ability in wastewater treatment of the catalysts. A comparison between different catalysts' characteristics was also studied. The r-GO@Pd/TiO2 showed a higher photocatalytic activity compared to Pd/TiO2 and commercial P25. Additionally, the complete dye reduction under visible light excitation indicated that wrapping r-GO round Pd/TiO2 improved the photocatalytic activity of catalysts. The determination of the stability of r-GO@Pd/TiO2 showed that its photocatalysis was persistent over several times of recycling examination. Therefore, r-GO@ Pd/TiO2 in wastewater treatment.


Assuntos
Cristalização/métodos , Grafite/química , Nanopartículas Metálicas/química , Nanocompostos/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Catálise , Grafite/efeitos da radiação , Luz , Teste de Materiais , Nanopartículas Metálicas/efeitos da radiação , Nanocompostos/efeitos da radiação , Óxidos/química , Paládio/química , Paládio/efeitos da radiação , Titânio/química , Titânio/efeitos da radiação , Águas Residuárias/química
19.
Environ Microbiol ; 17(12): 4898-915, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25331365

RESUMO

Iso-alkanes comprise a substantial proportion of petroleum and refined products that impact the environment, but their fate is cryptic under methanogenic conditions. We investigated methanogenic biodegradation of C7 and C8 iso-alkanes found in naphtha, specifically 2-methylhexane, 3-methylhexane, 2-methylheptane, 4-methylheptane and 3-ethylhexane. These were incubated as a mixture or individually with enrichment cultures derived from oil sands tailings ponds that generate methane from naphtha components; substrate depletion and methane production were monitored for up to 663 days. 3-Methylhexane and 4-methylheptane were degraded both singly and in the mixture, whereas 2-methylhexane and 2-methylheptane resisted degradation as single substrates but were depleted in the iso-alkane mixture, suggesting co-metabolism. 3-Ethylhexane was degraded neither singly nor with co-substrates. Putative metabolites consistent with succinylated C7 and C8 were detected, suggesting activation by addition of iso-alkanes to fumarate and corresponding to detection of alkylsuccinate synthase-like genes. 454 pyrotag sequencing, cloning and terminal restriction fragment length polymorphism of 16S rRNA genes revealed predominance of a novel member of the family Peptococcaceae (order Clostridiales) and Archaea affiliated with Methanoregula and Methanosaeta. We report here isomer-specific metabolism of C7 -C8 iso-alkanes under methanogenic conditions and propose their activation by a novel Peptococcaceae via addition to fumarate.


Assuntos
Alcanos/metabolismo , Biodegradação Ambiental , Euryarchaeota/metabolismo , Peptococcaceae/metabolismo , Petróleo/metabolismo , Alcanos/química , Carbono/metabolismo , Euryarchaeota/genética , Metano/metabolismo , Campos de Petróleo e Gás , Peptococcaceae/genética , Filogenia , RNA Ribossômico 16S/genética
20.
Artigo em Inglês | MEDLINE | ID: mdl-38500633

RESUMO

Depressed individuals tend to use maladaptive emotion regulation strategies more frequently than non-depressed individuals while using adaptive strategies (e.g., reappraisal) less frequently. Objective neural markers of emotion regulation ability could aid in identifying youth at greatest risk for depression and functional impairment more broadly. We used electroencephalography to examine emotion regulation in adolescents (aged 14-17; N = 201) with current depression (n = 94) and without any history of depression (n = 107) at high (n = 54) and low (n = 53) risk for depression based on a maternal history of depression. Results revealed group differences in event-related potential markers of emotion regulation using multiple scoring approaches. Never-depressed adolescents had significant reductions in mean-activity and principal component analysis-identified late positive potential responses to dysphoric stimuli under reappraisal instructions compared to passive viewing. There was no significant difference in neural responses between conditions among depressed adolescents. The magnitude of the reappraisal effects appeared slightly stronger for low-risk adolescents relative to high-risk. Exploratory analyses further demonstrated that the association between neural markers of emotion regulation and overall functioning was moderated by age, such that impaired emotion regulation abilities predicted poorer functioning among older adolescents. Findings support the sensitivity of the late positive potential to emotion regulation impairments in depression and psychopathology more broadly.

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