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1.
BMC Endocr Disord ; 23(1): 210, 2023 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-37777715

RESUMO

BACKGROUND: Type 1 diabetes (T1D) in youth is becoming a public health problem in Sub-Saharan Africa, including Burkina Faso. However, little is known about the level of knowledge of these patients on T1D. This study aimed to evaluate the knowledge of diabetes in adolescents and young adults about the disease, and identify the factors associated in Burkina Faso. METHODS: A cross-sectional survey was conducted from April to June 2020 among youth with T1D, aged 10 to 30 years, and regularly followed in the internal medicine department of Yalgado Ouedraogo University Hospital of Ouagadougou, Burkina Faso. Data were collected using the French AJD (Aide aux Jeunes Diabétiques) validated diabetes knowledge and skills (DKS) questionnaire designed to test participants' accuracy in knowledge about six different themes of T1D, as generalities of diabetes, hypoglycemia and hyperglycemia, management of insulin treatment, and self-monitoring blood glucose (SMBG). DKS level was determined by calculating the scores, and univariate and multivariate logistic regression were used to explore factors influencing DKS scores. This level was classified as insufficient or low ≤ 25/50, regular 26-39/50, and adequate or good ≥ 40/50. RESULTS: Sixty-three participants with a mean age of 19.05 years and a sex ratio (W/M) of 1.17 were included in our study. The mean HbA1c level was 9.79%, and 43 (68.23%) patients had an insufficient DKS level. The mean global DKS score of correct answers was 23.63/50. The percentage of correct answers was respectively 50% for the item "generalities of diabetes", 32.4% for the item "hypoglycemia and hyperglycemia", 67.72% for the item "diet", 37.34% for the item "management of insulin treatment" and 44.97% for the item "SMBG". In univariate analysis, a better patient DKS level was associated with university education and long duration of diabetes care follow-up (> 10 years, p < 0.05). Only increasing age remain associated with a better knowledge score (p < 0.05) in multivariate analysis. CONCLUSION: This study is an important first step in identifying areas for intervention efforts about therapeutic education for youth with type I diabetes in Burkina Faso.


Assuntos
Diabetes Mellitus Tipo 1 , Hiperglicemia , Hipoglicemia , Insulinas , Humanos , Adolescente , Adulto Jovem , Adulto , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/epidemiologia , Burkina Faso/epidemiologia , Estudos Transversais , Hiperglicemia/epidemiologia
2.
Eur J Pharm Biopharm ; 163: 252-265, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33745980

RESUMO

Lipid-based nanoparticles for RNA delivery (LNP-RNA) are revolutionizing the nanomedicine field, with one approved gene therapy formulation and two approved vaccines against COVID-19, as well as multiple ongoing clinical trials. As for other innovative nanopharmaceuticals (NPhs), the advancement of robust methods to assess their quality and safety profiles-in line with regulatory needs-is critical for facilitating their development and clinical translation. Asymmetric-flow field-flow fractionation coupled to multiple online optical detectors (MD-AF4) is considered a very versatile and robust approach for the physical characterisation of nanocarriers, and has been used successfully for measuring particle size, polydispersity and physical stability of lipid-based systems, including liposomes and solid lipid nanoparticles. However, the unique core structure of LNP-RNA, composed of ionizable lipids electrostatically complexed with RNA, and the relatively labile lipid-monolayer coating, is more prone to destabilization during focusing in MD-AF4 than previously characterised nanoparticles, resulting in particle aggregation and sample loss. Hence characterisation of LNP-RNA by MD-AF4 needs significant adaptation of the methods developed for liposomes. To improve the performance of MD-AF4 applied to LNP-RNA in a systematic and comprehensive manner, we have explored the use of the frit-inlet channel where, differently from the standard AF4 channel, the particles are relaxed hydrodynamically as they are injected. The absence of a focusing step minimizes contact between the particle and the membrane, reducing artefacts (e.g. sample loss, particle aggregation). Separation in a frit-inlet channel enables satisfactory reproducibility and acceptable sample recovery in the commercially available MD-AF4 instruments. In addition to slice-by-slice measurements of particle size, MD-AF4 also allows to determine particle concentration and the particle size distribution, demonstrating enhanced versatility beyond standard sizing measurements.


Assuntos
Portadores de Fármacos/química , Lipídeos/química , Nanopartículas/química , RNA/administração & dosagem , RNA/química , Fracionamento por Campo e Fluxo/métodos , Humanos , Nanomedicina/métodos , Tamanho da Partícula , Preparações Farmacêuticas/administração & dosagem , Preparações Farmacêuticas/química
3.
Gynecol Obstet Fertil ; 43(2): 144-50, 2015 Feb.
Artigo em Francês | MEDLINE | ID: mdl-25637039

RESUMO

INTRODUCTION: The purpose of this work was to study the continuation rate of intrauterine device (IUD) copper in a nulliparous population. PATIENTS AND METHOD: A prospective study in a family planning centre including nulliparous patients between January and December 2012. RESULTS: A total of 83 nulliparous patients had IUD copper insertion and 11 patients were excluded because they were lost to follow-up. Finally, 72 nulliparous patients were included in the study. Continuation rate after one-year follow-up was 90.3% (65/72). Satisfaction rate of patient was high (93.8%). Menstruation amount was increased for 84% (55/65) patients, but 75% (41/55) did not report any inconvenience about this. Dysmenorrhea were increased for 80% (52/65) patients, but 58% (30/52) were not troubled by this. CONCLUSION: Continuation rate of IUD copper was high (90%) after one-year follow-up in nulliparous women. Tolerance was also good for evaluated patients.


Assuntos
Dispositivos Intrauterinos de Cobre , Cooperação do Paciente , Satisfação do Paciente , Adulto , Feminino , Humanos , Paridade , Cooperação do Paciente/estatística & dados numéricos , Estudos Prospectivos
4.
Med Sante Trop ; 24(1): 49-54, 2014.
Artigo em Francês | MEDLINE | ID: mdl-24418900

RESUMO

OBJECTIVE: to describe the feasibility and results of at-home follow-up of mothers and newborns discharged early from the maternity ward after normal childbirth. METHOD: This prospective descriptive study took place during a one month period (April 1-30, 2011) in five maternity units in Bobo-Dioulasso, the second largest city in Burkina Faso. Mothers with normal vaginal deliveries and no complications at the sixth hour postpartum were included in the study with their newborns after informed oral consent. The discharge took place between 12 and 48 hours after delivery. The follow-up took place by telephone, home visits, and emergency hospital visits in cases of complications. A postnatal hospital visit was systematically planned for day 7. RESULTS: The study included 630 mothers and their babies. There were 1567 phone calls made: 27 women could not be reached by telephone after discharge, and 140 home visits took place, either at the mother's request or because of the failure to reach her by telephone. Complications were observed in 55 mothers and 135 babies. CONCLUSION: Postnatal follow-up at home is required for mothers and their newborns discharged early from the maternity ward after normal childbirth in view of the possibility of complications. This ensures continuity of care to improve survival of mothers and babies. As cell phones become more and more available, they may play an important role as a tool for such follow up.


Assuntos
Serviços de Assistência Domiciliar , Alta do Paciente , Cuidado Pós-Natal , Adulto , Burkina Faso , Estudos de Viabilidade , Feminino , Seguimentos , Humanos , Recém-Nascido , Doenças do Recém-Nascido/epidemiologia , Tempo de Internação , Estudos Prospectivos , Transtornos Puerperais/epidemiologia , Fatores de Tempo
5.
Mali Med ; 29(2): 38-46, 2014.
Artigo em Francês | MEDLINE | ID: mdl-30049126

RESUMO

The objectives of this prospective study, conducted from November 2011 to July 2013, in Bobo-Dioulasso were to evaluate seroprevalence of toxoplasma infection and to screen for maternal and congenital toxoplasmosis during pergravidic monitoring. MATERIAL AND METHODS: Techniques of High Sensitivity Direct Agglutination (HSDA) and Enzyme Linked Fluorescent Assay (ELFA) were used for the detection of IgG and IgM toxoplasma respectively. The IgG avidity assay was used for the dating of seroconversion. Screening and monitoring for fetal lesions were echographic. In case of seroconversion, a prenatal treatment with pyrimethamine and sulphonamide was introduced. Systematically and regularly immunoassay surveillance of newborn from cases of recent pergravidic toxoplasmosis was performed until complete and final negativity of serology. RESULTS: In total 301 pregnant women were included. The overall seroprevalence was 31.9%. Three cases of seroconversion (0.9%) including two cases at the 22nd and one at the 41th week of amenorrhea were noted. Series of obstetrical echography have detected no case of fetal Toxoplasma gondii infection and no congenital toxoplasmosis was detected. CONCLUSION: This study underlines the importance of implementation of a legal disposition for screening and routine monitoring of toxoplasmosis during pregnancy. This is due to the low rate (31.9%) of toxoplasma immunity among gestante in Burkina Faso that may lead to pergravidic acute toxoplasmosis or congenital toxoplasmosis whose outcome is often fatal.


Les objectifs de la présente étude prospective conduite de Novembre 2011 à Juillet 2013 à Bobo-Dioulasso ont été d'évaluer la séroprévalence de l'infection toxoplasmique et de dépister une toxoplasmose maternelle et congénitale au cours du suivi pergravidique. MATÉRIEL ET MÉTHODES: Les techniques d'agglutination haute sensibilité (ADHS) et ELFA (enzyme linked fluorescent assay) ont respectivement servi à la détection des IgG et d'IgM anti toxoplasmiques. Le test d'avidité des IgG a servi à la datation de la séroconversion. Le dépistage et le suivi des lésions fœtales ont été échographiques. En cas de séroconversion, un traitement anténatal associant pyriméthamine et sulfamide a été instauré. Une surveillance immunologique systématique et régulière du nouveau-né issu de cas de séroconversion toxoplasmqiue a été faite jusqu'à négativation complète et définitive de la sérologie. RÉSULTATS: Au total, 301 gestantes ont été incluses. La séroprévalence globale a été de 31,9%. Trois cas de séroconversion (0,9%) dont deux à la 22 ème et un à la 41ème semaine d'aménorrhée ont été notés. Les séries d'échographies obstétricales n'ont dépisté aucun cas d'infection toxoplasmique fœtale et aucune toxoplasmose congénitale n'a été détectée. CONCLUSION: Cette étude souligne l'intérêt de la mise en place d'une disposition légale de dépistage et de surveillance systématique de la toxoplasmose gestationnelle. Ceci en raison du faible taux (31,9%) de l'immunité toxoplasmique de la gestante au Burkina Faso qui peut conduire à une toxoplasmose aiguë pergravidique voire une toxoplasmose congénitale dont l'issue est parfois fatale.

6.
Sciences de la santé ; 1(1): 71-74, 2013.
Artigo em Francês | AIM (África) | ID: biblio-1271867

RESUMO

Objectifs : Determiner la frequence intra-hospitaliere des traumatismes corporels sur grossesse; identifier les circonstances de survenue et les types de traumatismes puis decrire le pronostic maternel et foetal Patientes et methodes : Il s'est agi d'une etude retrospective descriptive allant de 2007 a 2009; menee dans les services des urgences chirurgicales et obstetricales du CHU de Bobo-Dioulasso. Nous avons analyse les dossiers de toutes les femmes enceintes admises pour traumatisme corporel a la periode de l'etude. L'analyse des donnees a ete realisee avec le logiciel epi info version 6.0. Resultats : A la periode d'etude; nous avons enregistre 16053 admissions de femmes enceintes; soit une prevalence de 3;6. Les traumatismes ont concerne des femmes d'age moyen egal a 24 ans; menageres (74;1); citadines (81;1) et enceintes de 25 semaines d'amenorrhee. Les circonstances de survenue des traumatismes etaient les accidents de circulation (51;7); les rixes (29;30) et les chutes d'arbres (18;96). Il s'agissait de traumatismes abdominaux fermes (19); traumatismes des membres (10); traumatismes craniens (9); pelviens (4) et rachidiens (1). Le taux global des complications foto-maternelles etait 8;6 avec 17;2 de patientes decedees et 34;5 de morts fotales in utero. Conclusion : Les traumatismes au cours de la grossesse sont rares mais graves. L'on a deplore le deces d'une patiente et deux morts in utero dans cette serie. Se deplacer avec les engins a deux ou grimper dans les arbres doivent etre deconseilles aux femmes enceintes


Assuntos
Centros Médicos Acadêmicos , Acidentes por Quedas , Acidentes de Trânsito , Traumatismo Múltiplo , Gestantes
7.
Med Trop (Mars) ; 71(1): 49-52, 2011 Feb.
Artigo em Francês | MEDLINE | ID: mdl-21585091

RESUMO

OBJECTIVE: The purpose of this study was to evaluate the bacterial profile and antimicrobial susceptibility of surgical site infection (SSI) as a basis for optimizing probabilistic antibiotherapy. MATERIALS AND METHODS: A 6-month transversal retrospective study was carried out at the Souro Sano Hospital Laboratory from November 1st, 2006 to April 30th, 2007. All positive pus samples collected for etiologic diagnosis of SSI were included. RESULTS: In a series of 681 patients who underwent surgery at the hospital, SSI was observed in 159 cases for an incidence of 23.4%. Pus samples for etiologic diagnosis were collected from 112 patients and led to identification of 103 bacterial strains. The most common strains were enterobacteriaceae in 54.0%, gram-positive cocci in 29.0% and non-fermenting Gram-negative bacilli in 16.5%. Escherichia coli was the most common species (30%) followed by Staphylococcus aureus (16.5%) and Pseudomonas aeroginosa (12.0%). Enterobacteriaceae resistance rates were 71% to amoxicillin, 64% to clavulanic acid-amoxicillin and 15% to third generation cephalosporin. Most S. aureus isolates (85%) were sensitive to methicillin. Non-fermenting Gram-negative bacilli resistance rates were 68.5% to carboxypenicillin and 56% to fluoroquinolones. CONCLUSION: These findings indicate that SSI can be treated using third generation cephalosporin-aminosides in combination with oral fluoroquinolones.


Assuntos
Bactérias/isolamento & purificação , Infecção da Ferida Cirúrgica/microbiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Burkina Faso , Criança , Pré-Escolar , Estudos Transversais , Feminino , Hospitais , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
8.
Artigo em Francês | AIM (África) | ID: biblio-1260251

RESUMO

Objectif : Evaluer l'intégration du dépistage du cancer du col par IVA dans les services de soins après avortement (SAA) et de planification familiale (PF) dans un hôpital universitaire.Méthodologie : L'étude s'est déroulée dans les unités de Soins Après Avortement (SAA) et de planification familiale (PF) du CHU de Bobo Dioulasso au Burkina Faso. Les données ont été collectées rétrospectivement sur les clientes de PAC et de PF ayant bénéficié du dépistage du cancer du col par IVA pendant la période du 1er janvier 2009 au 31 aout 2010. Le personnel des deux unités a également été interrogé sur son point de vue sur l'intégration des services et les difficultés de sa mise en œuvre.Résultats : Le nombre de femmes ayant consulté dans les deux unités pendant la période de l'étude était de 3161. Leurs caractéristiques sociodémographiques étaient les suivantes : âge moyen de 32,8 ans, mariées dans 93,50% des cas, sans profession dans 78,8% ; gestité et parité moyennes respectives de 3,8 et 2,9 et un taux d'utilisation d'une méthode contraceptive de 66,7%. Au total 460 femmes ont bénéficié du dépistage des lésions précancéreuses par l'IVA soit 14,6% des consultantes et 70,2% de ces femmes ont bénéficié du dépistage en plus des soins pour lesquels elles ont consulté. L'IVA a été normal dans la majorité des cas (426 sur 460), positive chez 12 femmes et une IST a été diagnostiquée dans 54 cas (11,7%). Les principales difficultés évoquées par le personnel sont l'insuffisance de personnel formé et les problèmes logistiques.Conclusion : L'intégration du dépistage du cancer du col dans les services de SAA et de PF n'a pas donné les résultats escomptés dans les deux services à savoir l'augmentation de l'accès au dépistage. La formation du personnel, la résolution des problèmes logistiques dans les deux services ainsi qu'une meilleure organisation des soins doivent permettre d'améliorer le taux de dépistage


Assuntos
Aborto Induzido/enfermagem , Centros Médicos Acadêmicos , Ácido Acético , Burkina Faso , Serviços de Planejamento Familiar , Neoplasias do Colo do Útero
9.
Chir Main ; 29(2): 121-4, 2010 Apr.
Artigo em Francês | MEDLINE | ID: mdl-20299267

RESUMO

A case of ischemic gangrene of the right upper limb and hemiface noticed at birth is reported. It was a male baby born at term vaginally from a non diabetic mother. He was allowed in the surgical emergencies, 24 hours after the birth. The injuries were irreversible and required an arm amputation and a debridement of necrotic areas of the hemiface. The authors discuss the aetiology, the clinical features and the management of this rare condition.


Assuntos
Braço/irrigação sanguínea , Face/irrigação sanguínea , Doenças Fetais/etiologia , Doenças Fetais/cirurgia , Isquemia/etiologia , Isquemia/cirurgia , Amputação Cirúrgica , Burkina Faso , Desbridamento , Doenças Fetais/diagnóstico , Humanos , Recém-Nascido , Isquemia/diagnóstico , Masculino , Necrose , Doenças Raras , Índice de Gravidade de Doença
10.
AIDS Care ; 20(2): 146-9, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18293122

RESUMO

The aim of this study was to explore why patients in the urban Kibera slum, Nairobi, Kenya, offered free antiretroviral treatment (ART) at the Médecins Sans Frontièrs (MSF) clinic, choose not to be treated despite signs of AIDS. Qualitative semi-structured interviews were conducted with 26 patients, 9 men and 17 women. Six main reasons emerged for not accepting ART: a) fear of taking medication on an empty stomach due to lack of food; b) fear that side-effects associated with ART would make one more ill; c) fear of disclosure and its possible negative repercussions; d) concern for continuity of treatment and care; e) conflicting information from religious leaders and community, and seeking alternative care (e.g. traditional medicine); f) illiteracy making patients unable to understand the information given by health workers.


Assuntos
Terapia Antirretroviral de Alta Atividade/psicologia , Infecções por HIV/psicologia , Conhecimentos, Atitudes e Prática em Saúde , Recusa do Paciente ao Tratamento/psicologia , Adulto , Fármacos Anti-HIV/uso terapêutico , Feminino , Infecções por HIV/tratamento farmacológico , Humanos , Quênia , Masculino , Pessoa de Meia-Idade , Áreas de Pobreza
11.
Med Trop (Mars) ; 67(1): 43-7, 2007 Feb.
Artigo em Francês | MEDLINE | ID: mdl-17506272

RESUMO

Malaria is still a public health problem in many sub-Saharan countries. This study was undertaken to understand and analyze the relationship between local perceptions of malaria and practices for prevention and management in the department of Gaoua in Burkina Faso. The goal was to improve the effectiveness of prevention and management of malaria in the target population, i.e., children under the age of five. Individual interviews and focus groups using a semi-structured guide were carried out with mothers, traditional healthcare providers and elderly persons in four villages of the department of Gaoua. Findings showed that practices used for treatment and prevention were directly related to perceptions about malaria. Due to poverty, inadequate health service delivery and ignorance, people do not always seek medical attention and express doubts about the efficacy of modern care. Endogenous practices for malaria prevention are directly related to causes described by the population. Modern preventive techniques are not used by the population. For instance nets are misused to protect corpses from flies or for shelter during funerals.


Assuntos
Atitude do Pessoal de Saúde , Comportamentos Relacionados com a Saúde , Conhecimentos, Atitudes e Prática em Saúde , Malária/etiologia , Malária/prevenção & controle , Burkina Faso , Grupos Focais , Humanos , Entrevistas como Assunto , Pobreza
12.
Médecine Tropicale ; 67(1): 43-47, 2007.
Artigo em Francês | AIM (África) | ID: biblio-1266751

RESUMO

Le paludisme; maladie endemique; est encore un probleme de sante publique dans beaucoup de pays au sud du Sahara. Notre etude a concerne le departement de Gaoua et a eu pour objectif de comprendre et d'analyser les perceptions des populations face a la maladie et les strategies de prevention et de prise en charge du paludisme. Ainsi; sont concernes par cette etude les enfants de moins de cinq ans; la finalite etant d'ameliorer la prevention et la prise en charge efficace du paludisme. Pour ce faire; des entretiens individuels et des Focus groups ont ete realises a l'aide d'un guide d'entretien semi structure dans quatre villages du departement de Gaoua avec des meres d'enfants; des traditherapeutes et des personnes agees. L'etude a montre que; le paludisme est traite et prevenu en fonction des perceptions que les populations se font de cette maladie. En raison de la pauvrete; de la mauvaise qualite du service dans les formations sanitaires et de leurs perceptions; les populations ne recourent pas systematiquement aux formations sanitaires etmettent souvent en doute l'efficacite des traitementsmodernes. Il existe des moyens endogenes de prevention du paludisme qui sont directement en rapport avec les causes qu'evoquent les populations. Les moyens modernes de protection ne sont pas adoptes par les populations. La moustiquai- re est detournee de son usage traditionnel pour proteger dans certaines localites les cadavres contre les mouches ou pour servir d'abris lors des funerailles


Assuntos
Criança , Malária , Malária/etiologia
13.
Médecine Tropicale ; 67(1): 43-47, 2007.
Artigo em Francês | AIM (África) | ID: biblio-1266756

RESUMO

Le paludisme; maladie endemique; est encore un probleme de sante publique dans beaucoup de pays au sud du Sahara. Notre etude a concerne le departement de Gaoua et a eu pour objectif de comprendre et d'analyser les perceptions des populations face a la maladie et les strategies de prevention et de prise en charge du paludisme.Ainsi; sont concernes par cette etude les enfants de moins de cinq ans; la finalite etant d'ameliorer la prevention et la prise en charge efficace du paludisme. Pour ce faire; des entretiens individuels et des Focus groups ont ete realises a l'aide d'un guide d'entretien semi structure dans quatre villages du departement de Gaoua avec des meres d'enfants; des traditherapeutes et des personnes agees. L'etude a montre que; le paludisme est traite et prevenu en fonction des perceptions que les populations se font de cette maladie. En raison de la pauvrete; de la mauvaise qualite du service dans les formations sanitaires et de leurs perceptions; les populations ne recourent pas systematiquement aux formations sanitaires etmettent souvent en doute l'efficacite des traitementsmodernes. Il existe des moyens endogenes de prevention du paludisme qui sont directement en rapport avec les causes qu'evoquent les populations. Les moyens modernes de protection ne sont pas adoptes par les populations. La moustiquaire est detournee de son usage traditionnel pour proteger dans certaines localites les cadavres contre les mouches ou pour servir d'abris lors des funerailles


Assuntos
Criança , Malária , Malária/etiologia
15.
J Fr Ophtalmol ; 24(5): 463-6, 2001 May.
Artigo em Francês | MEDLINE | ID: mdl-11397980

RESUMO

PURPOSE: To identify the epidemiological features of ocular traumas in Burkina Faso. METHODS: A retrospective study was conducted in the eye department of the National Hospital of Ouagadougou, from January 1995 to 31 December 1997. All cases of eye trauma during this period were included. RESULTS: The study showed that ocular traumas represented 9.80% of the reasons for consultation in the unit. 73% of the patients were male. The median age was 21. School children and students were the most frequently involved 25.8%) and 58.9% of the patients came from Ouagadougou while 41.1% came from the rural areas. Public thoroughfare accidents (were the main causes of the trauma (25%). Among the traumatic agents, 26% involved vegetal materials. CONCLUSION: Ocular traumas are a major cause of blindness in Western Africa and concern mostly young people. Prevention strategies based on education and information about road safety could reduce the incidence of ocular traumatisms.


Assuntos
Traumatismos Oculares/epidemiologia , Traumatismos Oculares/etiologia , Pálpebras/lesões , Prevenção de Acidentes , Adolescente , Adulto , Distribuição por Idade , Idoso , Cegueira/etiologia , Burkina Faso/epidemiologia , Criança , Pré-Escolar , Traumatismos Oculares/prevenção & controle , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Avaliação das Necessidades , Vigilância da População , Características de Residência/estatística & dados numéricos , Estudos Retrospectivos , Fatores de Risco , Segurança , Distribuição por Sexo
16.
Opt Lett ; 22(10): 715-7, 1997 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-18185638

RESUMO

We investigated field screening mechanisms in large-aperture GaAs photoconductors, using an ultrafast pump--probe terahertz technique. After photoexcitation the bias field decreases to an intensity-dependent value as a result of near-field screening of the bias field. For longer delays the field exhibits an intensity-dependent decrease that results from a space-charge field caused by transport-induced charge separation. These measurements support recent theoretical results that the dominant saturation mechanism that limits terahertz output from large-aperture photoconductors is near-field screening of the bias field because the space-charge field develops on a much longer time scale than that of the terahertz pulse.

18.
Phys Rev B Condens Matter ; 50(8): 5783-5786, 1994 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-9976939
19.
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