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1.
J Interprof Care ; 38(1): 52-61, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-37366565

RESUMO

In Vietnam, each primary care community health center (CHC) consists of a multi-professional team with six disciplines, including a physician, assistant physician, nurse, pharmacist, midwife, and Vietnamese traditional physician, who are able to meet the majority of patient's needs at the primary care level. How they collaborate, especially in chronic disease management (CDM), is still limited described in the literature. This study aims to gain insight into the perceptions and the experiences of primary health care providers (PHCPs) toward interprofessional collaboration (IPC) in CDM in CHCs in (Hue) Vietnam. A qualitative study of descriptive phenomenology was performed using two focus groups and 15 semi-structured interviews with PHCPs from six professions relevant to CDM in CHCs. The data were analyzed using NVivo 12.0 with a thematic analysis method by a multiprofessional research team. From the analysis, the data were classified into three main themes: "lack of collaborative practice," "knowledge," and "facilitators and barriers to IPC." This study provided evidence of the awareness that actual collaboration in daily care is fragmentarily organized and that PHCPs try to finish their tasks within their profession. PHCPs work multiprofessionally and lack shared decision-making in patient-centered care. There is a need to develop an interprofessional education program and training to address these deficiencies in the Vietnamese context to improve interprofessional collaboration in health care.


Assuntos
Relações Interprofissionais , Médicos , Humanos , Vietnã , Atitude do Pessoal de Saúde , Pesquisa Qualitativa , Doença Crônica , Gerenciamento Clínico
2.
J Environ Sci (China) ; 139: 569-588, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38105077

RESUMO

Environmental pollution, such as water contamination, is a critical issue that must be absolutely addressed. Here, three different morphologies of tungsten-based photocatalysts (WO3 nanorods, WO3/WS2 nanobricks, WO3/WS2 nanorods) are made using a simple hydrothermal method by changing the solvents (H2O, DMF, aqueous HCl solution). The as-prepared nanocatalysts have excellent thermal stability, large porosity, and high hydrophilicity. The results show all materials have good photocatalytic activity in aqueous media, with WO3/WS2 nanorods (NRs) having the best activity in the photodegradation of bisphenol A (BPA) under visible-light irradiation. This may originate from increased migration of charge carriers and effective prevention of electron‒hole recombination in WO3/WS2 NRs, whereby this photocatalyst is able to generate more reactive •OH and •O2- species, leading to greater photocatalytic activity. About 99.6% of BPA is photodegraded within 60 min when using 1.5 g/L WO3/WS2 NRs and 5.0 mg/L BPA at pH 7.0. Additionally, the optimal conditions (pH, catalyst dosage, initial BPA concentration) for WO3/WS2 NRs are also elaborately investigated. These rod-like heterostructures are expressed as potential catalysts with excellent photostability, efficient reusability, and highly active effectivity in different types of water. In particular, the removal efficiency of BPA by WO3/WS2 NRs reduces by only 1.5% after five recycling runs and even reaches 89.1% in contaminated lake water. This study provides promising insights for the nearly complete removal of BPA from wastewater or different water resources, which is advantageous to various applications in environmental remediation.


Assuntos
Luz , Tungstênio , Tungstênio/química , Compostos Benzidrílicos/química , Água , Catálise
3.
4.
Emerg Infect Dis ; 29(5): 1002-1006, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37015283

RESUMO

We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions.


Assuntos
COVID-19 , Humanos , COVID-19/epidemiologia , SARS-CoV-2/genética , Vietnã/epidemiologia , Surtos de Doenças
5.
Chem Phys ; 564: 111709, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36188488

RESUMO

Inhibiting the biological activity of SARS-CoV-2 Mpro can prevent viral replication. In this context, a hybrid approach using knowledge- and physics-based methods was proposed to characterize potential inhibitors for SARS-CoV-2 Mpro. Initially, supervised machine learning (ML) models were trained to predict a ligand-binding affinity of ca. 2 million compounds with the correlation on a test set of R = 0.748 ± 0.044 . Atomistic simulations were then used to refine the outcome of the ML model. Using LIE/FEP calculations, nine compounds from the top 100 ML inhibitors were suggested to bind well to the protease with the domination of van der Waals interactions. Furthermore, the binding affinity of these compounds is also higher than that of nirmatrelvir, which was recently approved by the US FDA to treat COVID-19. In addition, the ligands altered the catalytic triad Cys145 - His41 - Asp187, possibly disturbing the biological activity of SARS-CoV-2.

6.
Cytopathology ; 34(4): 325-333, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36988122

RESUMO

BACKGROUND: Fine needle aspiration biopsy (FNAB), accompanied by classification systems for cytology, can offer a cheap and convenient option for the diagnosis of breast cancer in women with suspicious breast lumps. In this study, we aimed to assess the accuracy of the International Academy of Cytology (IAC) Yokohama system in a Vietnamese oncology centre. METHODS: A retrospective cross-sectional study was conducted from November 2021 to April 2022 at Vietnam National Cancer Hospital. We included patients with full hospital records regarding breast lesions for which FNAB was indicated. A total of 803 patients' FNAB specimens were assessed according to the IAC Yokohama system. The basic characteristics were summarised using the appropriate summary measurements. The risk of malignancy (ROM) was calculated for each classification category. RESULTS: The median age was 42.7 years (range: 14-85). The mean size of the lesions was 17.9 mm (range: 4-123 mm). We had 215 histopathological reports. The most common benign and malignant diagnoses were fibroadenoma and invasive carcinoma, respectively. The ROM for categories II, III, IV, and V was calculated as 3.4%, 37.5%, 95%, and 99.2% respectively. The sensitivity, specificity, positive predictive value, and negative predictive value were 96.4%, 97.2%, 98.5%, and 93.2%, respectively. CONCLUSION: The IAC Yokohama system offers a good option with which to predict underlying breast pathology using a simple and cheap procedure. However, pathologists require continuous training to ensure accurate interpretation of the slides.


Assuntos
Neoplasias da Mama , População do Sudeste Asiático , Adulto , Feminino , Humanos , Biópsia por Agulha Fina , Mama/patologia , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/patologia , Estudos Transversais , Estudos Retrospectivos , Sensibilidade e Especificidade , Vietnã , Adolescente , Adulto Jovem , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais
7.
BMC Med Educ ; 23(1): 798, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37880693

RESUMO

BACKGROUND: Interprofessional education (IPE) is expected to help prepare undergraduate health profession students to collaborate with other healthcare professionals in realising quality of care. Studies stress the necessity of students' readiness for interprofessional learning (IPL) in view of designing IPE programs. The present study aims to determine students' IPL-readiness and looks at related differences in students enrolled in different programs and at different phases in their educational program. METHODS: A cross-sectional survey study was set up among 1139 students from six health programs at HueUMP, using the Readiness for Interprofessional Learning Scale (RIPLS). Statistical analysis was performed using Kruskal-Wallis H and Mann-Whitney U tests. RESULTS: The overall mean RIPLS score was 68.89. RIPLS scores significantly differed between programs and between phases in the educational programs. Medical students presented a lower readiness level for IPL than students from other programs. In contrast to a significant increase in RIPLS scores of students in the clinical phase in Vietnamese traditional medicine, medicine, and pharmacy, a decrease in RIPLS scores was observed in students in the clinical phase in odonto-stomatology. CONCLUSIONS: The differences could be related to differences in educational programs and the study phases in a particular program. These results offer insights to direct the design and implementation of IPE in health education curricula and especially underscore the need to provide IPE throughout the curriculum.


Assuntos
Relações Interprofissionais , Estudantes de Ciências da Saúde , Humanos , Estudos Transversais , Vietnã , Educação em Saúde , Atitude do Pessoal de Saúde
8.
Arch Environ Contam Toxicol ; 85(3): 229-244, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37017706

RESUMO

Stable isotope signatures (δ13C, δ15N) and trace elements (TEs) were analyzed from invertebrates and fish to assess food web structure and the biomagnification or biodilution of Cu, Pb, Cd, Zn, Mn, Cr, Hg and As in coastal waters of Ha Tinh Province, Central Vietnam. δ13C and δ15N values of purported food sources (sediments, phytoplankton, macroalgae, and zooplankton) ranged from -21.24 ± 0.39‰ to -16.72 ± 1.02‰ and from 3.02 ± 0.70‰ to 7.30 ± 0.42‰, respectively. The δ13C and δ15N values in invertebrates and fish ranged from -19.75 ± 0.10‰ to -18.68 ± 0.40‰, and from 7.02 ± 1.21‰ to 9.10 ± 0.29‰. The δ15N values showed that the food web structure could be divided into four trophic levels. The benthic invertebrates had significantly higher concentrations of Cu, Pb, Zn, Cd and As. Hg concentrations tended to accumulate higher in the crabs and fish. The biodilution of Pb, Cd, Zn, Cr was observed throughout the food web, whereas biomagnification was observed for Cr, Mn, and As in bivalves; Cd and Zn in gastropods; Pb, Cd, Zn, and As in crabs; Cd in prawns and Hg in fish.


Assuntos
Mercúrio , Oligoelementos , Poluentes Químicos da Água , Animais , Oligoelementos/análise , Cádmio , Vietnã , Chumbo , Poluentes Químicos da Água/análise , Isótopos de Nitrogênio/análise , Invertebrados , Peixes , Mercúrio/análise , Cadeia Alimentar , Monitoramento Ambiental
9.
J Environ Manage ; 338: 117807, 2023 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-37037143

RESUMO

Increased agriculture and aquaculture production in the Mekong Delta during the last two decades has improved farmers' income, national export earnings and reduced poverty, but has also impacted on the environment and ecosystem services (ES) of importance to peoples' livelihoods and well-being. Through group discussions, interviews and questionnaires, this study assesses stakeholders' perceptions of the status and trends of ES in the Mekong Delta and how these have been influenced by agriculture development. 15 of 24 ES were assessed to be impacted negatively by agriculture intensification, and especially supporting and regulating ES (SRES). Only a few provisioning ES (PrES), related to farming, were assessed to be in a good and stable supply, because of human interventions to create favorable conditions for these ES. Among the ten highest ranked ES, eight belonged to PrES and two belonged to SRES. There was a positive correlation between rank and awareness of ES. The supply of most SRES was perceived to be in a low and declining status and assessed to be in a high need for improved management. Some ES, such as pest-control had been complemented with human-made substitutes, such as pesticides, which however sometimes weakened rather than strengthened the ES. Cultural ES (CES) were often ranked lower and of less management concern than the other groups of ES. It is concluded that future agriculture strategies need a more balanced management of ES for a long-term production of healthy food and increased resilience of the Mekong Delta to cope with future challenges, such as climate change and upstream dams.


Assuntos
Ecossistema , Praguicidas , Humanos , Áreas Alagadas , Agricultura , Renda , Conservação dos Recursos Naturais
10.
J Comput Chem ; 43(3): 160-169, 2022 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-34716930

RESUMO

AutoDock Vina (Vina) achieved a very high docking-success rate, p^ , but give a rather low correlation coefficient, R , for binding affinity with respect to experiments. This low correlation can be an obstacle for ranking of ligand-binding affinity, which is the main objective of docking simulations. In this context, we evaluated the dependence of Vina R coefficient upon its empirical parameters. R is affected more by changing the gauss2 and rotation than other terms. The docking-success rate p^ is sensitive to the alterations of the gauss1, gauss2, repulsion, and hydrogen bond parameters. Based on our benchmarks, the parameter set1 has been suggested to be the most optimal. The testing study over 800 complexes indicated that the modified Vina provided higher correlation with experiment Rset1=0.556±0.025 compared with RDefault=0.493±0.028 obtained by the original Vina and RVina1.2=0.503±0.029 by Vina version 1.2. Besides, the modified Vina can be also applied more widely, giving R≥0.500 for 32/48 targets, compared with the default package, giving R≥0.500 for 31/48 targets. In addition, validation calculations for 1036 complexes obtained from version 2019 of PDBbind refined structures showed that the set1 of parameters gave higher correlation coefficient ( Rset1=0.617±0.017 ) than the default package ( RDefault=0.543±0.020 ) and Vina version 1.2 ( RVina1.2=0.540±0.020 ). The version of Vina with set1 of parameters can be downloaded at https://github.com/sontungngo/mvina. The outcomes would enhance the ranking of ligand-binding affinity using Autodock Vina.

11.
J Chem Inf Model ; 61(5): 2302-2312, 2021 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-33829781

RESUMO

The COVID-19 pandemic has killed millions of people worldwide since its outbreak in December 2019. The pandemic is caused by the SARS-CoV-2 virus whose main protease (Mpro) is a promising drug target since it plays a key role in viral proliferation and replication. Currently, developing an effective therapy is an urgent task, which requires accurately estimating the ligand-binding free energy to SARS-CoV-2 Mpro. However, it should be noted that the accuracy of a free energy method probably depends on the protein target. A highly accurate approach for some targets may fail to produce a reasonable correlation with the experiment when a novel enzyme is considered as a drug target. Therefore, in this context, the ligand-binding affinity to SARS-CoV-2 Mpro was calculated via various approaches. The molecular docking approach was manipulated using Autodock Vina (Vina) and Autodock4 (AD4) protocols to preliminarily investigate the ligand-binding affinity and pose to SARS-CoV-2 Mpro. The binding free energy was then refined using the fast pulling of ligand (FPL), linear interaction energy (LIE), molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA), and free energy perturbation (FEP) methods. The benchmark results indicated that for docking calculations, Vina is more accurate than AD4, and for free energy methods, FEP is the most accurate method, followed by LIE, FPL, and MM-PBSA (FEP > LIE ≈ FPL > MM-PBSA). Moreover, atomistic simulations revealed that the van der Waals interaction is the dominant factor. The residues Thr26, His41, Ser46, Asn142, Gly143, Cys145, His164, Glu166, and Gln189 are essential elements affecting the binding process. Our benchmark provides guidelines for further investigations using computational approaches.


Assuntos
COVID-19 , Pandemias , Benchmarking , Humanos , Simulação de Acoplamento Molecular , Peptídeo Hidrolases , SARS-CoV-2
12.
Cleft Palate Craniofac J ; 58(4): 446-454, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-32924600

RESUMO

OBJECTIVE: The Kay Pentax nasometer uses a separator plate that touches the philtrum of a patient to separate the nasal and oral sound energies for nasalance measurement. However, the separator plate can restrict the natural movement of the patient's upper lip and generate unpleasant pressure on the patient's philtrum. The present study was intended to measure nasalance scores without touching the philtrum for better comfort during speech assessment and therapy. METHODS: Nasalance scores of 10 males and 10 females having no speech disorders were measured under 4 levels (0, 5, 10, and 15 mm) of the gap between the plate and the philtrum (denoted as plate-to-philtrum gap) using Nasometer II 6450 for nasal (Nasal Sentences) and oral (Zoo Passage) stimuli. Regression formulas were established to examine the relationships between nasalance score and plate-to-philtrum gap for the stimuli. To provide nasalance scores equivalent to those measured for the contact condition, compensation factors for the 5 mm plate-to-philtrum gap measurement condition were identified for the stimuli. RESULTS: The nasalance scores were significantly different between the 4 different plate-to-philtrum gaps for the stimuli. Compensation factors for the Nasal Sentences and the Zoo Passage were identified as 1.17 and 0.71, respectively. CONCLUSIONS: The 5 mm plate-to-philtrum gap condition after multiplying the compensation factors can provide equivalent nasalance scores to the conventional contact measurement condition which may provide better comfort in speech assessment and therapy.


Assuntos
Lábio , Fala , Feminino , Humanos , Masculino , Fonética , Acústica da Fala , Medida da Produção da Fala , Qualidade da Voz
13.
Molecules ; 25(15)2020 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-32707961

RESUMO

In previous studies, we isolated the known compound saponin XII from the roots of Dipsacus japonicus Miq. Here, we show that this compound reduced the number of acute myeloid leukemia OCI-AML3 cells as evaluated by a hemocytometer. Flow cytometry analyses demonstrated that the reported activity was associated with a significant increase of apoptosis and of cells in the G0/G1 phase of the cell cycle, with a decrease of cells in the S and G2/M phases. Thus, the inhibition of cell growth in OCI-AML3 cells was due to antiproliferative and pro-apoptotic effects. Interestingly, the bioactivity of saponin XII exerted its effect at a concentration as low as 1 µg/mL.


Assuntos
Antineoplásicos/química , Dipsacaceae/química , Inibidores do Crescimento/química , Leucemia Mieloide Aguda/tratamento farmacológico , Extratos Vegetais/química , Saponinas/química , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Descoberta de Drogas , Inibidores do Crescimento/farmacologia , Humanos , Extratos Vegetais/farmacologia , Saponinas/farmacologia
14.
Phys Chem Chem Phys ; 21(16): 8365-8375, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30941393

RESUMO

A systematic investigation on structure, relative stabilities, dissociation behavior and bonding of the singly and doubly Ni doped boron clusters BnNim with n = 2-22 and m = 1-2, was carried out using density functional theory (TPSSh functional) calculations. Calculated results indicate that for n < 14, BnNim structures are generally formed by capping Ni atom(s) on the edge or the surface of the pure boron Bn frameworks. From n = 14, the Ni dopants exert stronger effects in such a way that the most stable isomers BnNim adopt the shape of the related double ring tubular boron structures. With n ≥ 20, the Bn double ring appears to possess a large enough volume to entirely enclose the Ni2 dimer. The B14Ni and B22Ni2 turn out to be remarkable species with enhanced thermodynamic stability with larger average binding energies along with surprising geometric structures. Their higher thermodynamic stability can be understood in terms of the MO energy levels predicted by a hollow cylinder model, and other electronic properties. The (2 0 2)-orbital derived from the model of particle in a hollow cylinder appears to play a key role in the stabilization of the boron double ring.

15.
BMC Health Serv Res ; 19(1): 275, 2019 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-31046750

RESUMO

BACKGROUND: Patient experience with primary health care services can vary markedly between different types of health care facilities, even within the same country setting. Given known benefits of high quality primary health care, the performance of these facilities may significantly impact population health. The aim of this study was to compare the quality of primary care in different types of health facilities as experienced by Vietnamese consumers. METHODS: 1662 people who utilized primary health care services at least once over the past two years in various types of facilities in central Vietnam were surveyed in a cross-sectional study using the Vietnamese version of the Primary Care Assessment Tool (VN PCAT-AE) to assess overall primary care quality as well as several different domains of high quality primary care services. RESULTS: Commune health centers were associated with the highest overall primary care quality (PCAT expanded score 21.07, p < 0.001) as well as high scores in nearly all individual domains of primary care quality experienced by consumers compared with other types of facilities. Conversely, private facilities such as private clinics and pharmacies were rated lowest overall (PCAT expanded score 18.45, p < 0.05 and 16.90, p < 0.001 respectively). District hospitals and other government hospitals (PCAT expanded score 20.10 and 19.72 respectively) were reported as the best quality in comprehensiveness of available services (p < 0.001). Polyclinics performed quite well in comprehensiveness of services available (3.11) and first contact-access (2.79) but less so in other domains, especially in cultural competency (1.87). CONCLUSIONS: The high quality of primary care services experienced by consumers in commune health centers compared with other facilities gives Vietnam ample reason to promote greater use of these community-based primary care facilities. Populations may benefit most from building and strengthening grassroots networks of such community-based health centers as an effective solution for overcrowding at hospitals while simultaneously providing better overall health outcomes.


Assuntos
Instalações de Saúde/normas , Atenção Primária à Saúde , Qualidade da Assistência à Saúde , Adolescente , Adulto , Idoso , Centros Comunitários de Saúde , Estudos Transversais , Competência Cultural , Confiabilidade dos Dados , Feminino , Pesquisas sobre Atenção à Saúde , Acessibilidade aos Serviços de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Atenção Primária à Saúde/normas , Vietnã , Adulto Jovem
16.
Phys Chem Chem Phys ; 20(11): 7588-7592, 2018 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-29493696

RESUMO

Remarkably strong effects of the aromatic B3 cycle in stabilizing tubular silicon clusters were observed for the first time. The doped cluster B3@Si12+ presents a novel structural motif for silicon clusters in which a B3 cycle is encapsulated into a (6 × 2) Si12 prism giving rise to a high symmetry stable tubular structure (D3h). A large amount of electron density is transferred to the boron cycle, and the B3δ- unit not only retains a delocalized bonding pattern within the Si12 prism but also enables a two-fold aromaticity for the resulting silicon double ring. This double ring can be used as a building block to make longer nanotubes.

17.
Proc Natl Acad Sci U S A ; 112(44): 13639-44, 2015 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-26483491

RESUMO

Dogs were the first domesticated species, originating at least 15,000 y ago from Eurasian gray wolves. Dogs today consist primarily of two specialized groups--a diverse set of nearly 400 pure breeds and a far more populous group of free-ranging animals adapted to a human commensal lifestyle (village dogs). Village dogs are more genetically diverse and geographically widespread than purebred dogs making them vital for unraveling dog population history. Using a semicustom 185,805-marker genotyping array, we conducted a large-scale survey of autosomal, mitochondrial, and Y chromosome diversity in 4,676 purebred dogs from 161 breeds and 549 village dogs from 38 countries. Geographic structure shows both isolation and gene flow have shaped genetic diversity in village dog populations. Some populations (notably those in the Neotropics and the South Pacific) are almost completely derived from European stock, whereas others are clearly admixed between indigenous and European dogs. Importantly, many populations--including those of Vietnam, India, and Egypt-show minimal evidence of European admixture. These populations exhibit a clear gradient of short--range linkage disequilibrium consistent with a Central Asian domestication origin.


Assuntos
Cães/genética , Genética Populacional , Animais , Animais Domésticos , Ásia
18.
Chemistry ; 23(17): 4120-4127, 2017 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-28111816

RESUMO

The interaction of carbon monoxide with platinum alloy nanoparticles is an important problem in the context of fuel cell catalysis. In this work, molybdenum-doped platinum clusters have been studied in the gas phase to obtain a better understanding of the fundamental nature of the Pt-CO interaction in the presence of a dopant atom. For this purpose, Ptn+ and MoPtn-1+ (n=3-7) clusters were studied by combined mass spectrometry and density functional theory calculations, making it possible to investigate the effects of molybdenum doping on the reactivity of platinum clusters with CO. In addition, IR photodissociation spectroscopy was used to measure the stretching frequency of CO molecules adsorbed on Ptn+ and MoPtn-1+ (n=3-14), allowing an investigation of dopant-induced charge redistribution within the clusters. This electronic charge transfer is correlated with the observed changes in reactivity.

19.
J Phys Chem A ; 120(37): 7335-43, 2016 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-27556591

RESUMO

A systematic investigation on structure, dissociation behavior, chemical bonding, and magnetic property of Cr-doped Cun clusters (n = 9-16) is carried out using the mean of density functional theory calculations. It is found that CrCu12 is a crucial size, preferring an icosahedral Cu12 cage with the central Cr dopant. Smaller cluster sizes appear as on the way to form the CrCu12 icosahedron while larger ones are produced by attaching additional Cu atoms to the CrCu12 core. The presence of Cr dopant obviously enhances the stability of CrCun clusters in comparison to that of pure counterparts. Exceptionally stable CrCu12 has an 18-electron closed-shell electronic structure, mimicking a noble gas in the viewpoint of superatom concept. Analysis on cluster electronic structure shows that the interplay between 3d orbitals of Cr and 4s orbitals of Cu has a vital role on the magnetic properties of CrCun clusters.

20.
Bull Environ Contam Toxicol ; 97(1): 98-104, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27075585

RESUMO

This study assesses the effects of sequential applications of the insecticides Bassa 50EC (fenobucarb-F) and Vitashield 40EC (chlorpyrifos ethyl-CPF), sprayed at concentrations used by rice farmers in the Mekong Delta, on the brain acetylcholinesterase (AChE) in climbing perch fingerlings. After spraying the pesticides on the rice fields, the water concentrations of both insecticides decreased below the detection levels within 3 days. The sequential applications caused significant inhibition on the brain AChE activity in the exposed fish. The inhibition by F was quicker, but less prolonged, than for CPF. The inhibition levels caused by the sequential applications were lower than those caused by only CPF and by a mixture of CPF and F. The results indicate that sequential applications of pesticides could have a negative impact on aquatic organisms and fish yields, with implication for the aquatic biodiversity, local people's livelihood and the aquaculture industry in the Mekong Delta.


Assuntos
Acetilcolinesterase/metabolismo , Carbamatos/toxicidade , Inseticidas/toxicidade , Compostos Organotiofosforados/toxicidade , Oryza , Percas/metabolismo , Animais , Encéfalo/enzimologia , Clorpirifos , Vietnã
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