Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Mais filtros








Intervalo de ano de publicação
1.
Braz. j. biol ; 82: e238337, 2022. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1249249

RESUMO

Abstract Extensive field surveys were carried out to explore the distribution of Leisler's Bat Nyctalus leisleri (Kuhl, 1819) in selected area of FATA regions, Pakistan. Specimens of Leisler's Bat Nyctalus leisleri (Kuhl, 1819) (n5) were collected from Kurram Agency (Shublan) (N33.8229788 E70.1634414) at elevation 1427m and Khyber Agency (Landi Kotel) (N34.0909899 E71.1457517) at elevation 1091m for two years survey extending from May 2013 through August 2015. The mean head and body length, hind foot length, ear length and tail length the Nyctalus leisleri specimens captured from the study area was 65.08 ± 1.58 mm, 44.06 ± 0.52 mm, 8.38 ± 0.60 mm, 13.20 ± 0.99 mm and 39.46 ± 1.46 mm, respectively. For molecular analysis the sequences of COI gene were obtained and analyzed. The mean intraspecific divergences of Nyctalus leisleri was 0.04%. The mean interspecific divergences of Nyctalus noctula and Nyctalus leisleri was 0.2%. The mean concentration of each nucleotides was A = (26.3%), T = (32.8%), G = (15.9%) and C = (25.0%). The mean A+T contents were 59.2%and C+G were 40.9%. In the phylogenetic tree Nyctalus leisleri and Nyctalus noctula clustered with significant bootstrap support value.


Resumo Extensas pesquisas de campo foram realizadas para explorar a distribuição do morcego de Leisler Nyctalus leisleri (Kuhl, 1819), em uma área selecionada das regiões das FATA, Paquistão. Espécimes do morcego de Leisler Nyctalus leisleri (Kuhl, 1819) (n = 5) foram coletados na Agência Kurram (Shublan) (N33.8229788 E70.1634414), na elevação 1.427 m, e na Agência Khyber (Landi Kotel) (N34.0909899 E71.1457517), na elevação 1.091 m, por dois anos de pesquisa, estendendo-se de maio de 2013 a agosto de 2015. Os comprimentos médios da cabeça, do corpo, do pé traseiro, da orelha e da cauda dos espécimes de Nyctalus leisleri capturados na área de estudo foram de 65,08 ± 1,58 mm, 44,06 ± 0,52 mm, 8,38 ± 0,60 mm, 13,20 ± 0,99 mm e 39,46 ± 1,46 mm, respectivamente. Para análise molecular, foram obtidas e analisadas as sequências do gene COI. A média das divergências intraespecíficas de Nyctalus leisleri foi de 0,04%. As divergências interespecíficas médias de Nyctalus noctula e Nyctalus leisleri foram de 0,2%. A concentração média de cada nucleotídeos foi A = 26,3%, T = 32,8%, G = 15,9% e C = 25%. Os conteúdos médios de A + T foram de 59,2% e de C + G foram de 40,9%. Na árvore filogenética, Nyctalus leisleri e Nyctalus noctula agruparam-se com um valor significativo de suporte de bootstrap.

2.
Braz. j. biol ; 82: e243633, 2022. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1249273

RESUMO

Abstract Snow trout (Schizothorax plagiostomus) is an economically important freshwater fish, mostly found in northern areas of water reservoirs of Pakistan. The current study was conducted in River Swat to analyze the bioaccumulation of heavy metals (Pb, Cr, Ni, and Zn) in tissues of Schizothorax plagiostomus. Tissues were extracted and dissolved in perchloric acid (HClO4) and nitric acid (HNO3) along with hotplate. The heavy metals, zinc (Zn), lead (Pb), chromium (Cr), and Nickel (Ni) were determined using Perkin Elmer 2380 atomic absorption spectrophotometer. Results shows great variation in the content of the metal related to tissue type and sampling sites. A high concentration of bioaccumulation was reported at Charbagh, whereas lowest at Odigram: Charbagh>Landakai>Odigram. In the same way, Cr was the most accumulated heavy metal followed by lead, nickel, and Zinc:


Resumo A truta das neves (Schizothorax plagiostomus) é um peixe de água doce economicamente importante, encontrado principalmente nas áreas ao norte de reservatórios de água do Paquistão. O presente estudo foi realizado em River Swat para analisar a bioacumulação de metais pesados (Pb, Cr, Ni e Zn) em tecidos de Schizothorax plagiostomus. Os tecidos foram extraídos e dissolvidos em ácido perclórico (HClO4) e ácido nítrico (HNO3) com placa de aquecimento. Os metais pesados zinco (Zn), chumbo (Pb), cromo (Cr) e níquel (Ni) foram determinados usando espectrofotômetro de absorção atômica Perkin Elmer 2380. Os resultados mostram grande variação no conteúdo do metal relacionado ao tipo de tecido e locais de amostragem. Uma alta concentração de bioacumulação foi relatada em Charbagh, enquanto a mais baixa, em Odigram: Charbagh > Landakai > Odigram. Da mesma forma, Cr foi o metal pesado mais acumulado, seguido por Pb, Ni e Zn.

3.
Braz. j. biol ; 82: e238339, 2022. tab, graf
Artigo em Inglês | LILACS-Express | MEDLINE, LILACSEXPRESS | ID: biblio-1278513

RESUMO

Abstract The present research was carried out to explore the spider fauna of Buner valley with taxonomic study from February 2018 to January 2019. For this purpose samples were collected, four times at each month from 4 tehsils: Daggar, Gagra, Mandan and Totalai. Two methods were used, hand picking and sweep net for collection of samples. During day and night, three habitats, arid area, agriculture land and building area were search for collection. A total of 534 samples of spider were collected from four sampling sites, in which 379 were belonging to family Araniedae. After confirmation, the identified species were belonging to 8 genera (Neoscona, Argiope, Cyclosa, Araneus, Cyrtophora, Larinia, Erivoxia and Poltys) and 19 species. 18 of them were identified to specie level while a single specie to its generic level. The genus Neoscona was the dominant genus 26.31% having 5 species while the genus Argiope 21.05% is the second dominant having 4 species followed by Cyclosa 15.78% having 3 species followed by Cyrtophora and Araneus 10.52% having two species both. The Poltys and Larinia 5.26% are the rarest genera represent single-single specie both. Statistical analysis show that specie richness (D) = 5.77, Simpson index (1-D) = 0.87, Shannon index (H) = 2.33. Diversity of spiders was evenly distributed and calculated Evenness value was H/InS = 0.5408. There is also few atypical species and Fisher alpha estimate high value (Fisher α) = 4.42. Chao-1 estimated we have reported 22 species.


Resumo A presente pesquisa foi realizada para explorar a fauna de aranhas do vale Buner, em um estudo taxonômico realizado de fevereiro de 2018 a janeiro de 2019. Para esse fim, foram coletadas amostras, quatro vezes por mês, a partir de 4 subdistritos: Daggar, Gagra, Mandan e Totalai. Foram utilizados dois métodos, coleta manual e rede de varredura, para a obtenção das amostras. Durante o dia e a noite, foram pesquisados ​​três habitats: área árida, área agrícola e área de construção. Foram coletadas 534 amostras de aranha em quatro locais de amostragem, sendo que 379 pertenciam à família Araneidae. Após a confirmação, as espécies identificadas pertenciam a 8 gêneros (Neoscona, Argiope, Cyclosa, Araneus, Cyrtophora, Larinia, Erivoxia e Poltys) e a 19 espécies (18 delas foram identificados em seu nível de espécie, enquanto uma única foi identificada em seu nível genérico). O gênero Neoscona foi dominante (26,31%), com 5 espécies, seguido pelos gêneros Argiope (21,05%), com 4 espécies, Cyclosa (15,78%), com 3 espécies, e Cyrtophora e Araneus (10,52%), com 2 espécies. Poltys e Larinia (5,26%) são os gêneros mais raros, representando a mesma espécie. A análise estatística mostrou que a riqueza de espécies (D) foi de 5,77, o índice de Simpson (1-D) foi de 0,87 e o índice de Shannon (H) foi de 2,33. A diversidade de aranhas foi distribuída uniformemente, e o valor calculado da uniformidade foi H / InS = 0,5408. Também existem poucas espécies atípicas, e o alfa de Fisher (Fisher α) estimou o valor de 4,42. Já Chao-1 estimou 22 espécies.

4.
Artigo em Inglês | VETINDEXEXPRESS | ID: vti-762561

RESUMO

Abstract Extensive field surveys were carried out to explore the distribution of Leislers Bat Nyctalus leisleri (Kuhl, 1819) in selected area of FATA regions, Pakistan. Specimens of Leislers Bat Nyctalus leisleri (Kuhl, 1819) (n5) were collected from Kurram Agency (Shublan) (N33.8229788 E70.1634414) at elevation 1427m and Khyber Agency (Landi Kotel) (N34.0909899 E71.1457517) at elevation 1091m for two years survey extending from May 2013 through August 2015. The mean head and body length, hind foot length, ear length and tail length the Nyctalus leisleri specimens captured from the study area was 65.08 ± 1.58 mm, 44.06 ± 0.52 mm, 8.38 ± 0.60 mm, 13.20 ± 0.99 mm and 39.46 ± 1.46 mm, respectively. For molecular analysis the sequences of COI gene were obtained and analyzed. The mean intraspecific divergences of Nyctalus leisleri was 0.04%. The mean interspecific divergences of Nyctalus noctula and Nyctalus leisleri was 0.2%. The mean concentration of each nucleotides was A = (26.3%), T = (32.8%), G = (15.9%) and C = (25.0%). The mean A+T contents were 59.2%and C+G were 40.9%. In the phylogenetic tree Nyctalus leisleri and Nyctalus noctula clustered with significant bootstrap support value.


Resumo Extensas pesquisas de campo foram realizadas para explorar a distribuição do morcego de Leisler Nyctalus leisleri (Kuhl, 1819), em uma área selecionada das regiões das FATA, Paquistão. Espécimes do morcego de Leisler Nyctalus leisleri (Kuhl, 1819) (n = 5) foram coletados na Agência Kurram (Shublan) (N33.8229788 E70.1634414), na elevação 1.427 m, e na Agência Khyber (Landi Kotel) (N34.0909899 E71.1457517), na elevação 1.091 m, por dois anos de pesquisa, estendendo-se de maio de 2013 a agosto de 2015. Os comprimentos médios da cabeça, do corpo, do pé traseiro, da orelha e da cauda dos espécimes de Nyctalus leisleri capturados na área de estudo foram de 65,08 ± 1,58 mm, 44,06 ± 0,52 mm, 8,38 ± 0,60 mm, 13,20 ± 0,99 mm e 39,46 ± 1,46 mm, respectivamente. Para análise molecular, foram obtidas e analisadas as sequências do gene COI. A média das divergências intraespecíficas de Nyctalus leisleri foi de 0,04%. As divergências interespecíficas médias de Nyctalus noctula e Nyctalus leisleri foram de 0,2%. A concentração média de cada nucleotídeos foi A = 26,3%, T = 32,8%, G = 15,9% e C = 25%. Os conteúdos médios de A + T foram de 59,2% e de C + G foram de 40,9%. Na árvore filogenética, Nyctalus leisleri e Nyctalus noctula agruparam-se com um valor significativo de suporte de bootstrap.

5.
Braz J Biol ; 82: e238339, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34161423

RESUMO

The present research was carried out to explore the spider fauna of Buner valley with taxonomic study from February 2018 to January 2019. For this purpose samples were collected, four times at each month from 4 tehsils: Daggar, Gagra, Mandan and Totalai. Two methods were used, hand picking and sweep net for collection of samples. During day and night, three habitats, arid area, agriculture land and building area were search for collection. A total of 534 samples of spider were collected from four sampling sites, in which 379 were belonging to family Araniedae. After confirmation, the identified species were belonging to 8 genera (Neoscona, Argiope, Cyclosa, Araneus, Cyrtophora, Larinia, Erivoxia and Poltys) and 19 species. 18 of them were identified to specie level while a single specie to its generic level. The genus Neoscona was the dominant genus 26.31% having 5 species while the genus Argiope 21.05% is the second dominant having 4 species followed by Cyclosa 15.78% having 3 species followed by Cyrtophora and Araneus 10.52% having two species both. The Poltys and Larinia 5.26% are the rarest genera represent single-single specie both. Statistical analysis show that specie richness (D) = 5.77, Simpson index (1-D) = 0.87, Shannon index (H) = 2.33. Diversity of spiders was evenly distributed and calculated Evenness value was H/InS = 0.5408. There is also few atypical species and Fisher alpha estimate high value (Fisher α) = 4.42. Chao-1 estimated we have reported 22 species.


Assuntos
Aranhas , Animais , Biodiversidade , Ecossistema , Paquistão
6.
Braz J Biol ; 82: e243633, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34076166

RESUMO

Snow trout (Schizothorax plagiostomus) is an economically important freshwater fish, mostly found in northern areas of water reservoirs of Pakistan. The current study was conducted in River Swat to analyze the bioaccumulation of heavy metals (Pb, Cr, Ni, and Zn) in tissues of Schizothorax plagiostomus. Tissues were extracted and dissolved in perchloric acid (HClO4) and nitric acid (HNO3) along with hotplate. The heavy metals, zinc (Zn), lead (Pb), chromium (Cr), and Nickel (Ni) were determined using Perkin Elmer 2380 atomic absorption spectrophotometer. Results shows great variation in the content of the metal related to tissue type and sampling sites. A high concentration of bioaccumulation was reported at Charbagh, whereas lowest at Odigram: Charbagh>Landakai>Odigram. In the same way, Cr was the most accumulated heavy metal followed by lead, nickel, and Zinc.


Assuntos
Cyprinidae , Metais Pesados , Poluentes Químicos da Água , Animais , Bioacumulação , Monitoramento Ambiental , Metais Pesados/análise , Paquistão , Rios , Poluentes Químicos da Água/análise
7.
Cureus ; 13(4): e14433, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33996299

RESUMO

Background The occurrence of both tuberculosis (TB) and concomitant hepatitis B virus (HBV) is likely to be associated with poor patient outcomes and poor treatment response. Objective To assess whether tuberculosis patients with concomitant hepatitis B virus infection were prone to poorer outcomes and treatment response. Methodology A case-control study was undertaken at the Tuberculosis Centre, DHQ Bagh Azad Kashmir and Pulmonology Department, Lady Reading Hospital, Peshawar, between March 2020 and August 2020. All patients with diagnosed tuberculosis and coinfection with hepatitis B were labeled as the case group while those with only tuberculosis acted as the control. All patients with tuberculosis were managed on a directly observed treatment strategy (DOTS). Non-compliant patients and those without complete data were excluded from the study. All data regarding socio-demographics, laboratory investigations, and clinical characteristics were recorded in a predefined proforma. Patients were considered to have good treatment outcomes when patients completed the treatment or had a negative smear at six months of treatment. The Statistical Package for the Social Sciences (SPSS) version 26 (IBM Corp, Armonk, NY) was used for the data analysis. Results A total of 178 patients were enrolled in the study. It was found that patients with concomitant hepatitis B had significantly poorer outcomes as compared to patients who did not have hepatitis B (<0.001). Similarly, TB and hepatitis B patients were significantly associated with severe tuberculosis (<0.001) and required a higher frequency of retreatment (<0.001). Conclusion Our study reports a strong association between the treatment response of patients with tuberculosis with an added hepatitis B infection. Furthermore, a larger number of patients with hepatitis B had severe tuberculosis as compared to those without hepatitis B.

8.
Braz J Biol ; 82: e238337, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33978080

RESUMO

Extensive field surveys were carried out to explore the distribution of Leisler's Bat Nyctalus leisleri (Kuhl, 1819) in selected area of FATA regions, Pakistan. Specimens of Leisler's Bat Nyctalus leisleri (Kuhl, 1819) (n5) were collected from Kurram Agency (Shublan) (N33.8229788 E70.1634414) at elevation 1427m and Khyber Agency (Landi Kotel) (N34.0909899 E71.1457517) at elevation 1091m for two years survey extending from May 2013 through August 2015. The mean head and body length, hind foot length, ear length and tail length the Nyctalus leisleri specimens captured from the study area was 65.08 ± 1.58 mm, 44.06 ± 0.52 mm, 8.38 ± 0.60 mm, 13.20 ± 0.99 mm and 39.46 ± 1.46 mm, respectively. For molecular analysis the sequences of COI gene were obtained and analyzed. The mean intraspecific divergences of Nyctalus leisleri was 0.04%. The mean interspecific divergences of Nyctalus noctula and Nyctalus leisleri was 0.2%. The mean concentration of each nucleotides was A = (26.3%), T = (32.8%), G = (15.9%) and C = (25.0%). The mean A+T contents were 59.2%and C+G were 40.9%. In the phylogenetic tree Nyctalus leisleri and Nyctalus noctula clustered with significant bootstrap support value.


Assuntos
Quirópteros , Animais , Paquistão , Filogenia
10.
Exp Clin Endocrinol Diabetes ; 124(6): 380-4, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27219887

RESUMO

BACKGROUND: Interindividual genetic variations and environmental factors both play pivotal roles in the pathogenesis of metabolic syndrome (MetS). The rationale of this study conducted was to analyze the association of Matrix Metalloproteinase (MMP) gene variants, MMP-1 (-1607 1G/2G) and MMP-2 (-1306 C/T) with susceptibility to MetS and its effect on serum MMP level. METHODS: Study involved 370 subjects with 1:1 distribution of cases and controls. Patients were recruited according to modified NCEP-ATP III criteria for MetS. Clinical, biochemical analysis, PCR-RFLP and ELISA methods were employed for genotyping and estimation of serum MMP level. RESULTS: Significantly (p<0.001) higher Serum MMP-2 (39.13±19.96 ng/ml) was detected in cases as compared to controls. The MMP-2 (-1306 C/T) was significantly associated with the risk of MetS. The variant genotype TT was significantly associated with increased risk of MetS. (p=0.032; OR=2.31; 95%CI=1.07-4.97). No significant association of MMP-1(-1607 1G/2G) was found with risk of MetS. CONCLUSION: Our study concluded that presence of MMP-2 (-1306 C/T) might be associated the risk of MetS. Serum MMP2 level was significantly higher in patients and correlated with clinical parameters of MetS. Clinical implication of the work may help to identify the individuals with high risk of MetS and further complications.


Assuntos
Metaloproteinase 2 da Matriz/sangue , Síndrome Metabólica/sangue , Adulto , Estudos de Casos e Controles , Humanos , Metaloproteinase 1 da Matriz/sangue , Metaloproteinase 1 da Matriz/genética , Metaloproteinase 2 da Matriz/genética , Síndrome Metabólica/genética , Pessoa de Meia-Idade , Risco
11.
Ann Med Health Sci Res ; 3(3): 349-54, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24116312

RESUMO

BACKGROUND: Physicians have long recognized the association between diabetes mellitus and several pathologic conditions of the hand. The most commonly recognized maladies are limited joint mobility (LJM), Dupuytren's disease (DD), trigger finger (TF), and carpal tunnel syndrome (CTS). Incidence of these hand disorders has increased in the setting of diabetes. Collectively, these are described as diabetic hand syndrome. AIM: The aims were to find out the prevalence of hand disorders in diabetic patients, and to study the relation of these hand disorders with microvascular complications. SUBJECTS AND METHODS: This is an observational cross-sectional case-control study done over a period of 1 year Patients of type 2 DM, of age < 65 years, who visited Gandhi Memorial Hospital, Lucknow were enrolled and were described as cases. Age- and sex-matched nondiabetic individuals were taken in the control group. The data were analyzed using software SPSS. SPSS Inc. Released 2008. SPSS Statistics for Windows, Version 17.0. Chicago: SPSS Inc. Means and standard deviations were computed; the Student t-test and Chi-square (χ(2)) test were used as appropriate. RESULTS: A total of 400 subjects were studied, 200 each in the case and control groups. Of total 200 diabetic patients, 30% (60/200) patients had neuropathy, 37.5% (75/200) had nephropathy, and 44.5% (89/200) patients had retinopathy. In the study population, 67% patients were having one or more hand disorders, in which LJM was found in 40.5% (81/200) patients, DD was found in 19% (38/200) patients, TF in 16.5% (33/200), and CTS in 14% (28/200) patients. CONCLUSIONS: This study shows a high prevalence of hand disorders in diabetic patients and also correlates with the duration of type 2 DM, LJM being the most common hand disorder and more common in patients who have microvascular complications.

12.
BMJ Case Rep ; 20132013 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-23608838

RESUMO

A 42-year-old man presented with a history of recurrent loose motions for the previous 7 months. The patient also had a history of diabetes mellitus for the last 10 years and was uncontrolled on oral hypoglycaemic agents but responded to insulin. There was no history of any addiction. Examination and investigations showed the presence of malabsorption along with a calcified pancreas. The presence of a thrombus was also noted in the inferior vena cava. In the absence of alcohol intake, a diagnosis of fibrocalcific pancreatic diabetes was made and the patient was investigated for other hypercoagulable states but none was found. The patient was put on oral anticoagulants, insulin and pancreatic enzyme supplements, and currently, he is under regular follow-up for diabetes.


Assuntos
Diabetes Mellitus Tipo 2/complicações , Veia Cava Inferior , Trombose Venosa/etiologia , Adulto , Anticoagulantes/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diagnóstico Diferencial , Suplementos Nutricionais , Humanos , Insulina/uso terapêutico , Masculino , Tomografia Computadorizada por Raios X , Trombose Venosa/diagnóstico por imagem , Trombose Venosa/tratamento farmacológico
13.
Sci Pharm ; 79(1): 113-22, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21617776

RESUMO

A simple, specific and stability indicating reversed phase high performance liquid chromatographic method was developed for the simultaneous determination of paracetamol and lornoxicam in tablet dosage form. A Brownlee C-18, 5 µm column having 250×4.6 mm i.d. in isocratic mode, with mobile phase containing 0.05 M potassium dihydrogen phosphate:methanol (40:60, v/v) was used. The flow rate was 1.0 ml/min and effluents were monitored at 266 nm. The retention times of paracetamol and lornoxicam were 2.7 min and 5.1 min, respectively. The linearity for paracetamol and lornoxicam were in the range of 5-200 µg/ml and 0.08-20 µg/ml, respectively. Paracetamol and lornoxicam stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation and dry heat degradation. The proposed method was validated and successfully applied to the estimation of paracetamol and lornoxicam in combined tablet dosage form.

14.
Opt Express ; 17(5): 3765-70, 2009 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-19259217

RESUMO

We develop a rapid and efficient numeric technique for the design of arbitrary quasi-phase matched lattices for parametric generation of single and multiple pulses with any prescribed amplitude and phase profiles from fundamental frequency excitation in the regime of pump depletion. We examine the case of simultaneous of 2nd and 3rd harmonic generation in arbitrary quasi-phase matched gratings taking into account the group velocity mismatch and dispersion.

15.
Opt Express ; 16(3): 2115-21, 2008 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-18542291

RESUMO

We numerically demonstrate pulse shaping by backward frequency doubling of femtosecond laser pulses in engineered quasi-phase-matched waveguides. We employ optimal control theory to access the regime of pump depletion.


Assuntos
Desenho Assistido por Computador , Modelos Teóricos , Óptica e Fotônica/instrumentação , Processamento de Sinais Assistido por Computador/instrumentação , Simulação por Computador , Desenho de Equipamento , Análise de Falha de Equipamento
16.
Opt Express ; 16(1): 1-6, 2008 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-18521126

RESUMO

We develop an effective numerical algorithm to design engineered quasi-phase-matching gratings in nonlinear crystals for the parametric generation of harmonics of arbitrary order from a fundamental frequency input. We demonstrate the method in the case of lithium niobate excited by a continuous-wave source in the regime of pump depletion.


Assuntos
Desenho Assistido por Computador , Iluminação/instrumentação , Óptica e Fotônica/instrumentação , Refratometria/instrumentação , Refratometria/métodos , Algoritmos , Cristalização , Desenho de Equipamento , Análise de Falha de Equipamento
17.
Opt Lett ; 33(4): 378-80, 2008 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-18278116

RESUMO

The generation of tailored femtosecond pulses with fully engineered intensity and phase profiles is demonstrated using second-harmonic generation of an Er:fiber laser in an aperiodically poled lithium niobate crystal in the undepleted pump regime. Second-harmonic pulse shapes, including Gaussian, stepped, square, and multiple pulses have been characterized using cross-correlation frequency-resolved optical gating and have been shown to agree well with theory.

18.
Opt Lett ; 32(20): 2921-3, 2007 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-17938653

RESUMO

We propose and numerically investigate a simple scheme based on frequency-selective mirrors for compensating group-velocity mismatch during harmonic generation. We address the case of frequency doubling and illustrate the effectiveness of the approach for multipass frequency doubling in LiNbO(3).

19.
Opt Express ; 15(12): 7448-57, 2007 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-19547068

RESUMO

We numerically design quasi-phase matched crystals with domains of arbitrary sizes for second harmonic generation by femtosecond pulses, taking into account both group velocity mismatch and dispersion. An efficient simulated-annealing algorithm is developed to design quasi-phase matching gratings which can yield the desired amplitude and phase of second-harmonic pulses in the presence of pump depletion. The method is illustrated with reference to single, double-hump and chirped fs Gaussian pulses in a lithium niobate crystal.

20.
Appl Radiat Isot ; 52(3): 585-9, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10724410

RESUMO

The half-life of 233Pa has been determined by following the emission rates of eight gamma rays from the decay of 233Pa produced by neutron irradiation of 232Th. Several data evaluation procedures were used in the analysis of the half-life data. The measured half-life resulting from these measurements is 27.02(3) days. An evaluation in conjunction with 4 literature values leads to 26.975(13) days as the current best estimate of the half-life of 233Pa.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA