Search | SciELO

Need help?

Add field +

Search history

No documents were found for your search

Results: 10

au:LAZARO, S.

Filters

Collection + Options

All
Brazil

9
Argentina

1

Journal + Options

All
Food Science and Technology

2
Química Nova

2
Brazilian Journal of Pharmaceutical Sciences

1
Cerâmica

1
Engenharia Agrícola

1
Journal of the Brazilian Chemical Society

1
Revista argentina de reumatología

1
Rodriguésia

1

Language

All
Portuguese

2

Publication Year + Options

All
2019

3
2020

2
2004

1
2010

1
2016

1
2018

1
2022

1

SciELO Thematic Areas + Options

All
Agricultural Sciences

3
Exact and Earth Sciences

3
Health Sciences

2
Biological Sciences

1
Engineering

1

Show all...

WoS Subject Categories + Options

All
Chemistry

3
Multidisciplinary

3
Science

3
Food

2
Technology

2
Agricultural

1
Ceramics

1
Ecology

1
Engineering

1
Materials

1
Pharmacology

1
Pharmacy

1
Plant

1
Rheumatology

1
Sciences

1

Show all...

WoS Citation Index + Options

All
Science Citation Index Expanded

6
Social Sciences Citation Index

1

Citables and non citables

All
Citable

10

Type of Literature

All
Article

10

Order by

Page of 1 Next

Select this page

Print | Send to email | Export |

Facebook
Twitter
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

0 Selected itens

List all
Erase all

Promising antifungal activity of two varieties of Capsicum chinense against Sclerotinia sclerotiorum, Rhizopus stolonifer and Colletotrichum goleosporoides
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

TOIGO, Sandriny Evillin Machado

; FERNANDES, Cassia Cristina

; MIRANDA, Mayker Lazaro Dantas

Food Science and Technology

Journal Metrics
- Sobre o periódico
- SciELO Analytics

2022, Volume 42 elocation e52722

Abstract: En | Text: En | PDF: En

Abstract Peppers (Capsicum sp.) which belong to the Solanaceae family constitute an important segment in the vegetable sector, both in agriculture and in the food industry. This paper aims to investigate in vitro antifungal activity of hexane extracts from Capsicum chinense fruit (unripe bode pepper – ‘HE-UB’ – and ripe little beak pepper – ‘HE-RB’) against Sclerotinia sclerotiorum, Rhizopus stolonifer and Colletotrichum gloeosporioides. Antifungal activity was evaluated by the disk diffusion method (DDM) at doses between 25 µL and 300 µL of both diluted extracts. Chemical analyses revealed that the major constituent in both extracts was E-caryophyllene. HE-RB inhibited 100% of S. sclerotiorum, R. stolonifer and C. gloeosporioides growth at doses of 200 µL, 100 µL and 300 µL, respectively. HE-UB also inhibited 100% of fungal growth at doses of 100 µL (S. sclerotiorum), 150 µL (C. gloeosporioides) and 200 µL (R. stolonifer). HE-RB and HE-UB were active against the fungi under study; thus, screening of medicinal plants provides another alternative to produce chemical fungicides that are relatively non-toxic and cost-effective.

https://doi.org/10.1590/fst.52722

Bioactivities of essential oils from different parts of Spiranthera odoratissima (Rutaceae)
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Cabral, Fernando Duarte

; Fernandes, Cassia Cristina

; Ribeiro, Arthur Barcelos

; Squarisi, Iara Squarisi

; Tavares, Denise Crispim

; Candido, Ana Carolina Bolela Bovo

; Magalhães, Lizandra Guidi

; Souza, João Matias de

; Martins, Carlos Henrique Gomes

; Miranda, Mayker Lazaro Dantas

Rodriguésia

Journal Metrics
- Sobre o periódico
- SciELO Analytics

2020, Volume 71 elocation e00902019

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo Este trabalho tem por objetivo investigar, pela primeira vez, as atividades antituberculose, antileishmania e antiproliferativa in vitro dos óleos essenciais (OEs) obtidos de folhas e flores de S. odoratissima. Avaliamos a atividade antimicobacteriana em termos da Concentração Inibitória Mínima (CIM). Os OEs mostraram ser antimicrobianos ativos contra M. tuberculosis, com valores de CIM de 150 µg/mL (folhas) e 162,5 µg/mL (flores). Os óleos apresentam significativa atividade antiparasitária contra a forma promastigota de L. amazonensis, com valores de CI50 (50% de inibição do crescimento) de 14,36 ± 2,02 (folhas) e 19,89 ± 2,66 µg/mL (flores). A atividade antiproliferativa em linhagem celular normal (GM07492A, fibroblastos de pulmão) e tumorais (MCF-7, HeLa e M059J) foi realizada utilizando o ensaio XTT; os resultados foram expressos a partir do cálculo da Concentração Inibitória de 50% do crescimento celular (CI50) e o índice de seletividade foi calculado. OEs de folhas e flores apresentaram um CI50 de 502,97 ± 40,33 µg/mL e 370,60 ± 2,01 µg/mL para a linhagem GM07492A, respectivamente. Observou-se atividade antiproliferativa contra todas as linhagens celulares tumorais humanas, com valores de CI50 significativamente inferiores aos obtidos para a linhagem celular normal, demonstrando valores de CI50 para a linhagem MCF-7 (367,57 ± 4,46 µg/mL para OEs folhas e 357,70 ± 1,85 µg/mL para OEs flores) e M059J (492,53 ± 56,67 µg/mL para OEs folhas e 324,90 ± 6,72 µg/mL para OEs flores). Estes resultados in vitro mostraram que OEs de S. odoratissima podem ser um possível candidato que atue como agente antimicobacteriano, antiparasitário e antitumoral.

Abstract This paper aims to investigate, for the first time, in vitro antitubercular, antileishmanial and antiproliferative activities of essential oils (EOs) from S. odoratissima leaves and flowers - grown in midwestern Brazil - against Mycobacterium tuberculosis, promastigote forms of Leishmania amazonensis and human tumor cell lines. Antimycobacterial activity of EOs was evaluated in terms of the minimal inhibitory concentration (MIC). EOs from leaves and flowers showed to be active antimicrobials against M. tuberculosis, since MIC values were 150 µg/mL and 162.5 µg/mL, respectively. Both EOs exhibited significant activity against promastigote forms of L. amazonensis; IC50 values (50% growth inhibition) were 14.36 ± 2.02 (EOs from leaves) and 19.89 ± 2.66 µg/mL (EOs from flowers). Antiproliferative activity in normal (GM07492A, lung fibroblasts) and tumor (MCF-7, HeLa and M059J) cell lines was performed by the XTT assay; results were expressed as IC50 (50% cell growth inhibition) and the selective index was calculated. IC50 values of EOs from leaves and flowers obtained in normal cell lines for were 502.97 ± 40.33 µg/mL and 370.60 ± 2.01 µg/mL, respectively. Antiproliferative activity was observed against human tumor cell lines, whose IC50 values were significantly lower than those obtained in normal cell lines of MCF-7 cells (367.57 ± 4.46 µg/mL-EOs from leaves and 357.70 ± 1.85 µg/mL-EOs from flowers) and M059J cells (492.53 ± 56.67 µg/mL-EOs from leaves and 324.90 ± 6.72 µg/mL-EOs from flowers), thus, indicating selectivity. These in vitro results showed that EOs from S. odoratissima may be an antimycobacterial, antiparasitic and antitumor agent.

https://doi.org/10.1590/2175-7860202071050 376 downloads

Chemical composition and in vitro antibacterial activity of essential oils from Murraya paniculata (L.) Jack (Rutaceae) ripe and unripe fruits against bacterial genera Mycobacterium and Streptococcus
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Silva, Flávia Fernanda Alves da

; Fernandes, Cassia Cristina

; Santiago, Mariana Brentini

; Martins, Carlos Henrique Gomes

; Vieira, Tatiana Manzini

; Crotti, Antônio Eduardo Miller

; Miranda, Mayker Lazaro Dantas

Brazilian Journal of Pharmaceutical Sciences

Journal Metrics
- Sobre o periódico
- SciELO Analytics

2020, Volume 56 elocation e18371

Abstract: En | Text: En | PDF: En

This study aims to investigate chemical composition of essential oils from Murraya paniculata (L.) Jack (Rutaceae) ripe and unripe fruits and determine their in vitro antibacterial activity. Essential oils were extracted by hydrodistillation from Murraya paniculata (L.) Jack ripe and unripe fruits collected in the Cerrado, in Rio Verde, southwestern Goiás, Brazil. They were analyzed by gas chromatography with flame ionization detector (GC-FID) and by gas chromatography-mass spectrometry (GC-MS). Sesquiterpenes, which represent the most abundant class of compounds in oils, predominated in both ripe and unripe fruits. Major constituents of essential oils extracted from ripe fruits (RF-EO) were (-caryophyllene (21.3%), (-ylangene (13.3%), germacrene-D (10.9%) and (-zingiberene (9.7%) whereas the ones of unripe fruits (UF-EO) were sesquithujene (25.0%), (-zingiberene (18.2%), germacrene-D (13.1%) and (-copaene (12.7%). In vitro antibacterial activity of essential oils was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method in 96-well microplates. Both essential oils under investigation showed moderate anti-streptococcal activity against the following bacteria: Streptococcus mutans, S. mitis, S. sanguinis, S. sobrinus and S. salivarius. MIC values ranged between 100 and 400 µg/mL. Regarding the antimycobacterial activity, essential oils from M. paniculata (L.) Jack unripe and ripe fruits were active against Mycobacterium kansasii (MIC = 250 µg/mL), moderately active against M. tuberculosis (MIC = 500 µg/mL) and inactive against M. avium (MIC = 2000 µg/mL). This study was pioneer in revealing similar chemical profiles of both essential oils extracted from Murraya paniculata (L.) Jack unripe and ripe fruits, besides describing their in vitro anti-streptococcal and antimycobacterial activities.

https://doi.org/10.1590/s2175-97902019000418371 621 downloads

Chemical constituents of essential oil from Murraya paniculata leaves and its application to in vitro biological control of the fungus Sclerotinia sclerotiorum
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

SILVA, Flávia Fernanda Alves da

; ALVES, Cassia Cristina Fernandes

; OLIVEIRA FILHO, Josemar Gonçalves de

; VIEIRA, Tatiana Manzini

; CROTTI, Antônio Eduardo Miller

; MIRANDA, Mayker Lazaro Dantas

Food Science and Technology

Journal Metrics
- Sobre o periódico
- SciELO Analytics

dec 2019, Volume 39 Pages 413 - 417

Abstract: En | Text: En | PDF: En

ABSTRACT Besides their value as therapeutic resources, medicinal plants may also be used as sources of active ingredients against phytopathogens. Fungi can grow and cause spoilage in food, thus, resusting in decrease in its quality and quantity. This research aimed at evaluating the effect of essential oil from Murraya paniculata (ML-EO) leaves on mycelial growth of Sclerotinia sclerotiorum, a fungus that poses high risk to several cultures, mainly soybean. Essential oil from M. paniculata (Rutaceae) leaves was obtained by hydrodistillation which was carried out by a Clevenger-type apparatus while its chemical composition was analyzed by GC-FID and GC-MS. β-Caryophyllene (23.8%), α-zingiberene (21.0%) and β-cubebene (10.2%) were the main constituents found in ML-EO leaves. In vitro antifungal activity showed that ML-EO, at a 300 µL dose, inhibited 91.2% of mycelial growth of Sclerotinia sclerotiorum . This is the first report of the antifungal activity of ML-EO against S. sclerotiorum and results suggest that the essential oil under evaluation has good potential to control this phytopathogenic fungus.

https://doi.org/10.1590/fst.20218 506 downloads

HDL-PARTICLES SEPARATION EMPLOYING DIFFERENT PRECIPITATING AGENTS: FUNCTIONAL PROPERTIES OF THE IMPACT OF CHEMICAL PRECIPITATION ON LIPOPROTEIN PARTICLE-SIZE AND PARAOXONASE-1-ACTIVITY
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Silva, Vanessa R. A. e

; Albuquerque, Elaine C.

; Santos, Ana Paula C. dos

; Santos, Julio C. A.

; Junior, Lazaro S. S.

; Presada, William A.

; Vinagre, Carmen G. C. de M.

; Couto, Ricardo D.

Química Nova

Journal Metrics
- Sobre o periódico
- SciELO Analytics

aug 2019, Volume 42 N. 8 Pages 859 - 865

Abstract: En | Text: En | PDF: En

First-generation methods used to quantify HDL-cholesterol have been used for decades. Therefore, first-generation precipitatingreagents still in use, the chemical impact on HDL-particles functionality (structure/activity-relationship) is not well-documented. The study aim was to identify the most efficient precipitating-reagent for lipoprotein separation to be used in the HDL functionalevaluation. A cross-sectional design with convenience sampling was conducted. Plasma samples from 40 individuals, both genders, were evaluated. Biochemical analysis was performed after using different chemical precipitants (e.g. polyethylene glycol - PEG (P1), phosphotungstic-acid (P2), and dextran-sulfate/MgCl2 (P3)) to evaluate HDL-particle-size and PON1-activity. Parametric and non-parametric tests were performed using GraphPad-Prism 5.01 (USA). Differences were considered significant when a p-value < 0.05 were obtained. The PON1-activity comparison differed after NaCl stimulation (p < 0.001, paired t-test) and among chemical precipitant treatments. The PON1-activity differed after sample precipitation with P1 when compared to P2, and P3 (p < 0.05; ANOVA), before and after stratification for dyslipidemia group. The HDL particle-size comparison did not differ, but on the other hand, polydispersity differed after sample precipitation with P3 when compared to P1 or P2 (p < 0.05; ANOVA). Dextran- Sulfate/MgCl2 was a better chemical precipitant for PON1-activity, and PEG for HDL-particle-size, respectively. The HDL functional

https://doi.org/10.21577/0100-4042.20170410 1096 downloads

Sexto reporte de eventos adversos con tratamientos biológicos en Argentina: Informe del registro BIOBADASAR
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics

Gómez, G.

; Pons-Estel, G.

; Citera, G.

; Soriano, E.

; Saurit, V.

; Benavidez, F.

; Velozo, E.

; Dubinsky, D.

; Exeni, I.

; Gobi, C.

; Gómez, G.

; Díaz, M.

; Granel, A.

; Smichowsky, A.

; Garate, G.

; Quinteros, A.

; Cavillon, E.

; Petkovic, I.

; Larroude, M.S.

; de la Sota, M.

; Cappuccio, A.M.

; Berbotto, G.

; Alvarez, A.

; Papasidero, S.

; Lazaro, A.

; Garcia, M.

; Sacnun, M.

; Soares de Souza, S.

; Bertoli, A.

; Bejarano, V.

; Rillo, O.

; Kerzberg, E.

; Quintana, R.

; Agüero, S.

; Somma, L.

; Cruzat, V.

; Battaglitti, C.

; Perez Dávila, A.

; Gallardo, M.

; Pereira, D.

; Verando, M.

; Paira, S.

; Martinez, L.

; Aste, N.

; Pisoni, C.

; Catay, E.

; Graf, C.

; Casado, G.

; de la Vega, M.

Revista argentina de reumatología

Journal Metrics
- Sobre o periódico
- SciELO Analytics

mar 2019, Volume 30 N. 1 Pages 4 - 9

Abstract: En Es | Text: En Es | PDF: En | PDF: Es

Objective: Update the results of the BIOBADASAR registry on safety, duration and causes of treatment interruption after 8 years of follow-up. Methods: BIOBADASAR is a safety record of biological therapies established by the Argentine Society of Rheumatology. The description of BIOBADASAR 3.0 is presented, a cohort of 53 centers in Argentina followed prospectively from August 2010 to January 2018. Results: 4656 patients were registered, 6234 treatments [3765 cases (therapy with biologicals) and 2469 controls (non-biological therapy)]. Treatment was interrupted in 44.6% in cases vs. 27.9% in controls. Main cause of discontinuation was due to inefficiency (40% cases vs. 32% controls). There were 3154 adverse events (2230 in cases vs. 924 in controls), of which 13.6% were tombs (9.8% in cases and 3.7% in controls). The most frequent adverse event (AE) in both groups were infections (43.56% in cases vs. 34.31% in controls, RR: 3.42, 95% CI: 3.02-3.88), and the upper airway pathways (14.5%). Neoplasms were published in 78 cases versus 45 controls (RR: 1.98, 95% CI: 1.37-2.86). Conclusions: In this article, there are no different trends regarding safety, duration and causes of interruption of treatment compared to previous reports. Infections were the main causes of treatment discontinuation. The advent of new biological agents and the need for control over long-term security, strengthens the use of this type of registration.

Objetivo: Actualizar los resultados del registro BIOBADASAR sobre seguridad, duración y causas de interrupción del tratamiento luego de 8 años de seguimiento. Métodos: BIOBADASAR es un registro de seguridad de terapias biológicas establecido por la Sociedad Argentina de Reumatología. Se presenta la descripción de BIOBADASAR 3.0, una cohorte compuesta por 53 centros de Argentina seguidos prospectivamente desde agosto de 2010 hasta enero de 2018. Resultados: Se registraron 4656 pacientes, 6234 tratamientos [3765 casos (terapia con biológicos) y 2469 controles (terapia no biológicos)]. Se interrumpió el tratamiento en el 44,6% en los casos vs. 27,9% en los controles. Causa principal de discontinuación fue por ineficacia (40% casos vs. 32% controles). Se presentaron 3154 eventos adversos (2230 en casos vs. 924 en controles), de los cuales el 13,6% fueron graves (9,8% en casos y 3,7% en controles). El evento adverso (EA) más frecuente en ambos grupos fueron las infecciones (43,56% en casos vs. 34,31% en los controles, RR: 3,42; IC 95%: 3,02-3,88), y de ellas las de vías aéreas superiores (14,5%). Las neoplasias se presentaron en 78 casos vs. 45 en controles (RR: 1,98; IC 95%: 1,37-2,86). Conclusiones: En este sexto reporte no se observan tendencias diferentes sobre seguridad, duración y causas de interrupción del tratamiento respecto a informes previos. Las infecciones fueron el principal EA y la ineficacia, seguido por EA y la pérdida de pacientes las principales causas de suspensión del tratamiento. El advenimiento de nuevos agentes biológicos y la necesidad de control en seguridad a largo plazo, fortalece el uso de este tipo de registro.

197 downloads

HR-MAS NMR Allied to Chemometric on Hancornia speciosa Varieties Differentiation
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Flores, Igor S.

; Silva, Andressa K.

; Furquim, Leonnardo C.

; Castro, Carlos F. S.

; Chaves, Lazaro J.

; Collevatti, Rosane G.

; Lião, Luciano M.

Journal of the Brazilian Chemical Society

Journal Metrics
- Sobre o periódico
- SciELO Analytics

apr 2018, Volume 29 N. 4 Pages 708 - 714

Abstract: En | Text: En | PDF: En

This work describes the potential of chemometric analyses applied to 1H high-resolution magic angle spinning nuclear magnetic resonance (1H HR-MAS NMR) data for the chemotaxonomic investigation of Hancornia speciosa (Apocynaceae) varieties. This plant, popularly known as mangaba, has a complex morphological differentiation and thus chemical analyses can be used for their taxonomic classification. In comparison to traditional techniques, 1H HR-MAS NMR allied with chemometrics provided a simple and low cost method for chemotaxonomy. Leaves of four varieties of H. speciosa from a common garden experiment was studied and demonstrated that H. speciosa var. speciosa differs from others due to its specific metabolic profile, and var. pubescens was discriminated based on its high phenolic compound content. The distinction between the latter variety and gardineri is important once it allows for the selection of samples with greater commercial value, once they produce the largest and heaviest fruits.

https://doi.org/10.21577/0103-5053.20170191 573 downloads

Ba-DOPED ZnO MATERIALS: A DFT SIMULATION TO INVESTIGATE THE DOPING EFFECT ON FERROELECTRICITY
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics
- Dimensions
- PlumX
- Altmetric

Lacerda, Luis H. da S.

; Lazaro, Sergio R. de

Química Nova

Journal Metrics
- Sobre o periódico
- SciELO Analytics

apr 2016, Volume 39 N. 3 Pages 261 - 266

Abstract: En | Text: En | PDF: En

ZnO is a semiconductor material largely employed in the development of several electronic and optical devices due to its unique electronic, optical, piezo-, ferroelectric and structural properties. This study evaluates the properties of Ba-doped wurtzite-ZnO using quantum mechanical simulations based on the Density Functional Theory (DFT) allied to hybrid functional B3LYP. The Ba-doping caused increase in lattice parameters and slight distortions at the unit cell angle in a wurtzite structure. In addition, the doping process presented decrease in the band-gap (Eg) at low percentages suggesting band-gap engineering. For low doping amounts, the wavelength characteristic was observed in the visible range; whereas, for middle and high doping amounts, the wavelength belongs to the Ultraviolet range. The Ba atoms also influence the ferroelectric property, which is improved linearly with the doping amount, except for doping at 100% or wurtzite-BaO. The ferroelectric results indicate the ZnO:Ba is an strong option to replace perovskite materials in ferroelectric and flash-type memory devices.

https://doi.org/10.5935/0100-4042.20160023 2375 downloads

Desempenho de válvulas antigotas e microaspersores
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics

Sandri, Delvio

; Bessa, Kady S. E.

; Mesquita, Márcio

; Prado, Lazaro C. R. A.

Engenharia Agrícola

Journal Metrics
- Sobre o periódico
- SciELO Analytics

aug 2010, Volume 30 N. 4 Pages 627 - 636

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Nos últimos anos, foram introduzidos novos modelos de dispositivos para cultivo em ambiente protegido, como as válvulas antigotas e microaspersores, necessitando-se avaliar o desempenho dos mesmos. Assim, o objetivo deste trabalho foi avaliar o desempenho hidráulico de válvulas antigotas novas e usadas, sob baixa e alta pressão, em microaspersores do grupo modular e modelo Hadar. O CVf e CVq do conjunto microaspersor e válvula antigotas de baixa pressão e somente o microaspersor modular foram classificados como ruins ou inaceitáveis e a válvula anti-gotas modular de alta pressão nova como inaceitável. A válvula Hadar apresentou o melhor desempenho para todas as pressões de serviço. As válvulas avaliadas abriram em pressões inferiores às indicadas pelos seus fabricantes. O tempo de uso interferiu no desempenho das válvulas antigotas modular de baixa pressão, sendo o modelo novo o que apresentou menor índice de CVf para a pressão de abertura e fechamento.

In the last years new models of devices were introduced for greenhouse cultivation, as the leak-preventing device and microsprinkler, it is needed to evaluate their performance. So the objective of this work was to evaluate the hydraulic performance of new and used leak-preventing device, under low and high pressure in microsprinkler of modular group and Hadar model. The CVf and CVq of the microsprinkler and the leak-preventing device of low pressure only the microsprinkler of modular group were classified as bad or unacceptable and the new high pressure as unacceptable. The leak-preventing device Hadar presented the best performance for all the performances. The leak-preventing device opened in low pressures as indicated by their manufacturers. The long time using interfered in the performance of the leak-preventing device of low pressure modular group, being the new model which presented smaller values of CVf for the opening and closing pressure.

2877 downloads

10.

O papel dos modificadores de rede na produção da fotoluminescência no CaWO4
Facebook Twitter

Other social networks
Google+
LinkedIn
Reddit
StambleUpon
CiteULike
Mendeley
Other networks

Metrics
- SciELO Analytics

Ciaco, F. R. C.

; Pontes, F. M.

; Pinheiro, C. D.

; Leite, E. R.

; Lazaro, S. R. de

; Varela, J. A.

; Pizani, P. S.

; Paskocimas, C. A.

; Souza, A. G.

; Longo, E.

Cerâmica

Journal Metrics
- Sobre o periódico
- SciELO Analytics

mar 2004, Volume 50 N. 313 Pages 43 - 49

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Discutiu-se a fotoluminescência para o tungstato de cálcio amorfo, observada à temperatura ambiente. Verificou-se que há concordância entre os resultados experimentais e teóricos. Neste trabalho foram simuladas as estruturas cristalinas e amorfas do tungstato de cálcio (CaWO4), comparando-se as respectivas estruturas eletrônicas. Os resultados dos cálculos teóricos indicam a formação de novos níveis de energia na banda de valência e de condução do amorfo. Estes níveis eletrônicos extras são os responsáveis pela formação da cauda na curva do espectro de absorção. Correspondentemente, medidas experimentais de absorção óptica mostraram a presença da cauda, com relação ao espectro do cristalino. Desta forma, pode-se interpretar a formação da cauda, como sendo associada aos defeitos promovidos na estrutura desordenada do material amorfo.

We discuss the nature of visible photoluminescence at room temperature in amorphous calcium tungstate taking into account the results of recent experimental and quantum mechanical theoretical studies. Our investigation of the electronic structure involved the use of first-principle molecular calculations to simulate the variation of the electronic structure in the calcium tungstate crystalline phase, which is known to have a direct band gap, and we also made an in-depth examination of amorphous calcium tungstate. The results of our theoretical calculations of amorphous calcium tungstate indicate that the formation of threefold coordination in the amorphous system may introduce delocalized electronic levels in the HOMO (highest occupied molecular orbital) and the LUMO (lowest unoccupied molecular orbital). These delocalized electronics levels are related to the formation of a tail in the absorbency spectrum curve. The results indicate that amorphous calcium tungstate has the conduction band near the band gap dominated by Ca states contribution. Experimental optical absorption measurements showed the presence of a tail. These results are interpreted by the nature of these exponential optical edges and tails, associated with defects promoted by the disordered structure of the amorphous material. We associate them with delocalized states in the band gap.

2251 downloads

Showing

itens per page

Page of 1 Next

Select one or more results

All Alphabetic

Results

Comparative chart Download CSV

Statistics of

Send result

To*

Use ; (semicolon) to insert more emails.

Send to email

This page

Selected records

All references (max. 300)

Your email

Subject

Comments

Export format:

RIS (for EndNote, ProCite, Reference Manager, RefWorks, Citavi, etc.)

BibTeX

Citation

CSV (for Excel, etc)

Export:

This page

Selected itens

All references (max. 2000)

Sem resultados

No documents were found for your search

Glossary and search help

You can enrich your search in a very simple way. Use the search indexes combined with the connectors (AND or OR) and specify more your search.

For example, if you want to search for articles about
cases of dengue in Brasil in 2015, use:
ti:dengue and publication_year:2015 and aff_country:Brasil

See below the complete list of search indexes that can be used:

Index code	Element
ti	article title
au	author
kw	article keywords
subject	subject (title words, abstract and keywords)
ab	abstract
ta	journal short title (e.g. Cad. Saúde Pública)
journal_title	journal full title (e.g. Cadernos de Saúde Pública)
la	publication language code (e.g. pt - Portuguese, es - Spanish)
type	document type
pid	publication identifier
publication_year	publication year of publication
sponsor	sponsor
aff_country	country code of the author's affiliation
aff_institution	author affiliation institution
volume	article volume
issue	article issue
elocation	elocation
doi	DOI number
issn	journal ISSN
in	SciELO colection code (e.g. scl - Brasil, col - Colômbia)
use_license	article usage license code

SciELO - Scientific Electronic Library Online
Rua Dr. Diogo de Faria, 1087 – 9º andar – Vila Clementino 04037-003 São Paulo/SP - Brasil
Email: scielo@scielo.org

All the contents of this site www.scielo.br, except where otherwise noted, is licensed under a Creative Commons Attribution License.
more »