998 resultados para Transdutor de 5 a 10 MHz
Resumo:
AIM: To study the development of motor speed and associated movements in participants aged 5 to 18 years for age, sex, and laterality. METHOD: Ten motor tasks of the Zurich Neuromotor Assessment (repetitive and alternating movements of hands and feet, repetitive and sequential finger movements, the pegboard, static and dynamic balance, diadochokinesis) were administered to 593 right-handed participants (286 males, 307 females). RESULTS: A strong improvement with age was observed in motor speed from age 5 to 10, followed by a levelling-off between 12 and 18 years. Simple tasks and the pegboard matured early and complex tasks later. Simple tasks showed no associated movements beyond early childhood; in complex tasks associated movements persisted until early adulthood. The two sexes differed only marginally in speed, but markedly in associated movements. A significant laterality (p<0.001) in speed was found for all tasks except for static balance; the pegboard was most lateralized, and sequential finger movements least. Associated movements were lateralized only for a few complex tasks. We also noted a substantial interindividual variability. INTERPRETATION: Motor speed and associated movements improve strongly in childhood, weakly in adolescence, and are both of developmental relevance. Because they correlate weakly, they provide complementary information.
Resumo:
Improving safety at nighttime work zones is important because of the extra visibility concerns. The deployment of sequential lights is an innovative method for improving driver recognition of lane closures and work zone tapers. Sequential lights are wireless warning lights that flash in a sequence to clearly delineate the taper at work zones. The effectiveness of sequential lights was investigated using controlled field studies. Traffic parameters were collected at the same field site with and without the deployment of sequential lights. Three surrogate performance measures were used to determine the impact of sequential lights on safety. These measures were the speeds of approaching vehicles, the number of late taper merges and the locations where vehicles merged into open lane from the closed lane. In addition, an economic analysis was conducted to monetize the benefits and costs of deploying sequential lights at nighttime work zones. The results of this study indicates that sequential warning lights had a net positive effect in reducing the speeds of approaching vehicles, enhancing driver compliance, and preventing passenger cars, trucks and vehicles at rural work zones from late taper merges. Statistically significant decreases of 2.21 mph mean speed and 1 mph 85% speed resulted with sequential lights. The shift in the cumulative speed distributions to the left (i.e. speed decrease) was also found to be statistically significant using the Mann-Whitney and Kolmogorov-Smirnov tests. But a statistically significant increase of 0.91 mph in the speed standard deviation also resulted with sequential lights. With sequential lights, the percentage of vehicles that merged earlier increased from 53.49% to 65.36%. A benefit-cost ratio of around 5 or 10 resulted from this analysis of Missouri nighttime work zones and historical crash data. The two different benefitcost ratios reflect two different ways of computing labor costs.
Resumo:
The water content dynamics in the upper soil surface during evaporation is a key element in land-atmosphere exchanges. Previous experimental studies have suggested that the soil water content increases at the depth of 5 to 15 cm below the soil surface during evapo- ration, while the layer in the immediate vicinity of the soil surface is drying. In this study, the dynamics of water content profiles exposed to solar radiative forcing was monitored at a high temporal resolution using dielectric methods both in the presence and absence of evaporation. A 4-d comparison of reported moisture content in coarse sand in covered and uncovered buckets using a commercial dielectric-based probe (70 MHz ECH2O-5TE, Decagon Devices, Pullman, WA) and the standard 1-GHz time domain reflectometry method. Both sensors reported a positive correlation between temperature and water content in the 5- to 10-cm depth, most pronounced in the morning during heating and in the afternoon during cooling. Such positive correlation might have a physical origin induced by evaporation at the surface and redistribution due to liquid water fluxes resulting from the temperature- gradient dynamics within the sand profile at those depths. Our experimental data suggest that the combined effect of surface evaporation and temperature-gradient dynamics should be considered to analyze experimental soil water profiles. Additional effects related to the frequency of operation and to protocols for temperature compensation of the dielectric sensors may also affect the probes' response during large temperature changes.
Resumo:
CREB is a cAMP-responsive nuclear DNA-binding protein that binds to cAMP response elements and stimulates gene transcription upon activation of the cAMP signalling pathway. The protein consists of an amino-terminal transcriptional transactivation domain and a carboxyl-terminal DNA-binding domain (bZIP domain) comprised of a basic region and a leucine zipper involved in DNA recognition and dimerization, respectively. Recently, we discovered a testis-specific transcript of CREB that contains an alternatively spliced exon encoding multiple stop codons. CREB encoded by this transcript is a truncated protein lacking the bZIP domain. We postulated that the antigen detected by CREB antiserum in the cytoplasm of germinal cells is the truncated CREB that must also lack its nuclear translocation signal (NTS). To test this hypothesis we prepared multiple expression plasmids encoding carboxyl-terminal deletions of CREB and transiently expressed them in COS-1 cells. By Western immunoblot analysis as well as immunocytochemistry of transfected cells, we show that CREB proteins truncated to amino acid 286 or shorter are sequestered in the cytoplasm, whereas a CREB of 295 amino acids is translocated into the nucleus. Chimeric CREBs containing a heterologous NTS fused to the first 248 or 261 amino acids of CREB are able to drive the translocation of the protein into the nucleus. Thus, the nine amino acids in the basic region involved in DNA recognition between positions 287 and 295 (RRKKKEYVK) of CREB contain the NTS. Further, mutation of the lysine at position 290 in CREB to an asparagine diminishes nuclear translocation of the protein.(ABSTRACT TRUNCATED AT 250 WORDS)
Resumo:
BACKGROUND: Postoperative chemoradiotherapy (CRT) of gastric carcinoma improves survival among high- risk patients. This study was undertaken to analyse long-term survival probability and the impact of certain covariates on the survival outcome in affected individuals. MATERIALS AND METHODS: Between January 2000 and December 2005, 244 patients with gastric cancer underwent adjuvant radiotherapy (RT) in our institution. Data were retrieved retrospectively from patient files and analysed with SPSS version 21.0. RESULTS: A total of 244 cases, with a male to female ratio of 2.2:1, were enrolled in the study. The median age of the patients was 52 years (range, 20-78 years). Surgical margin status was positive or close in 72 (33%) out of 220 patients. Postoperative adjuvant RT dose was 46 Gy. Median follow-up was 99 months (range, 79-132 months) and 23 months (range, 2-155 months) for surviving patients and all patients, respectively. Actuarial overall survival (OS) probability for 1-, 3-, 5- and 10-year was 79%, 37%, 24% and 16%, respectively. Actuarial progression free survival (PFS) probability was 69%, 34%, 23% and 16% in the same consecutive order. AJCC Stage I-II disease, subtotal gastrectomy and adjuvant CRT were significantly associated with improved OS and PFS in multivariate analyses. Surgical margin status or lymph node dissection type were not prognostic for survival. CONCLUSIONS: Postoperative CRT should be considered for all patients with high risk of recurrence after gastrectomy. Beside well-known prognostic factors such as stage, lymph node status and concurrent chemotherapy, the type of gastrectomy was an important prognostic factor in our series. With our findings we add to the discussion on the definition of required surgical margin for subtotal gastrectomy. We consider that our observations in gastric cancer patients in our clinic can be useful in the future randomised trials to point the way to improved outcomes.
Resumo:
Os parâmetros dosimétricos de um feixe de raios X de pequeno diâmetro para um sistema de radiocirurgia comercial foram medidos em água com um detector de diodo de Si do tipo p. As razões tecido-máximo, o fator de espalhamento total e os perfis dos feixes a profundidades de 5 e 10 cm foram medidos para 17 feixes de diâmetros circulares de 5 mm a 50 mm, em incrementos de 2,5 mm. Os fatores de espalhamento totais caíram lentamente, de 0,947 para 0,888 entre os cones de 50 mm e 12,5 mm de diâmetro (variação de 7%); para os cones entre 10 mm e 5 mm de diâmetro, esta queda foi bem maior, de 0,854 para 0,666 (variação de 28%). Os valores obtidos para a relação tecido-máximo são consistentes com dados publicados. Os perfis dos feixes foram medidos nas direções x e y, e estão dentro de 0,2 mm para todos os cones entre as duas direções. A medida da largura à meia-altura se encontra dentro de 1 mm com o diâmetro nominal dos cones.
Resumo:
Este estudo propôs-se a revisar os aspectos relevantes da anatomia, técnica de exame e achados de imagens, com o objetivo de auxiliar o radiologista no diagnóstico diferencial frente às afecções músculo-tendinosas do ombro. Foram realizadas 34 ultra-sonografias da região do ombro, no período de janeiro a dezembro de 2001. A avaliação foi realizada com transdutores de alta freqüência (7,5-10 MHz). O exame foi normal em 23% dos pacientes (oito casos). Dos 26 casos alterados, observaram-se oito com ruptura total (30%), cinco com ruptura parcial (19%), dez com tendinopatia (38%), um com tendinopatia calcificada (3%), um com tenossinovite bicipital (3%) e um com tendinopatia associada a artrite gotosa (3%). A falta de experiência e de conhecimento das principais alterações que acometem o ombro é um dos principais pontos limitantes do diagnóstico ultra-sonográfico das lesões do ombro. Portanto, o estudo dessas alterações deve ser realizado amplamente.
Resumo:
PURPOSE: The MOSAIC (Multicenter International Study of Oxaliplatin/Fluorouracil/Leucovorin in the Adjuvant Treatment of Colon Cancer) study has demonstrated 3-year disease-free survival (DFS) and 6-year overall survival (OS) benefit of adjuvant oxaliplatin in stage II to III resected colon cancer. This update presents 10-year OS and OS and DFS by mismatch repair (MMR) status and BRAF mutation. METHODS: Survival actualization after 10-year follow-up was performed in 2,246 patients with resected stage II to III colon cancer. We assessed MMR status and BRAF mutation in 1,008 formalin-fixed paraffin-embedded specimens. RESULTS: After a median follow-up of 9.5 years, 10-year OS rates in the bolus/infusional fluorouracil plus leucovorin (LV5FU2) and LV5FU2 plus oxaliplatin (FOLFOX4) arms were 67.1% versus 71.7% (hazard ratio [HR], 0.85; P = .043) in the whole population, 79.5% versus 78.4% for stage II (HR, 1.00; P = .980), and 59.0% versus 67.1% for stage III (HR, 0.80; P = .016) disease. Ninety-five patients (9.4%) had MMR-deficient (dMMR) tumors, and 94 (10.4%) had BRAF mutation. BRAF mutation was not prognostic for OS (P = .965), but dMMR was an independent prognostic factor (HR, 2.02; 95% CI, 1.15 to 3.55; P = .014). HRs for DFS and OS benefit in the FOLFOX4 arm were 0.48 (95% CI, 0.20 to 1.12) and 0.41 (95% CI, 0.16 to 1.07), respectively, in patients with stage II to III dMMR and 0.50 (95% CI, 0.25 to 1.00) and 0.66 (95% CI, 0.31 to 1.42), respectively, in those with BRAF mutation. CONCLUSION: The OS benefit of oxaliplatin-based adjuvant chemotherapy, increasing over time and with the disease severity, was confirmed at 10 years in patients with stage II to III colon cancer. These updated results support the use of FOLFOX in patients with stage III disease, including those with dMMR or BRAF mutation.
Resumo:
The thermal decomposition reaction of trans-3,6-dimethyl-3,6-diphenyl-1,2,4,5-tetraoxacyclohexane (acetophenone cyclic diperoxide, DPAF), in different solvents (methanol, 1,4-dioxane, acetonitrile and 2-propanol/benzene mixtures) in the initial concentration and temperature ranges of (4.2-10.5) x 10-3 M and 140.0 to 185.0 ºC, respectively, follows a pseudo first order kinetic law up to at least 70% DPAF conversion. An important solvent effect on the rate constant values, activation parameters (DH# and DS#) and reaction products obtained in different solvents is detected, showing that the reaction is accelerated in alcohols.
Resumo:
OBJETIVOS: avaliar o desempenho de diversas características ultra-sonográficas morfológicas (12) e doplervelocimétricas (7), para detecção de metástases linfonodais em mulheres com câncer de mama. MÉTODOS: foram incluídas 179 mulheres (181 axilas), entre janeiro e dezembro de 2004. Os exames ultra-sonográficos foram realizados com transdutor linear em tempo real (Toshiba-Power Vision-6000 (modelo SSA-370A)). Para o estudo de parâmetros morfológicos foram utilizadas freqüências entre 7,5 e 12 MHz. Para os parâmetros Doppler foi utilizada freqüência de 5 MHz. Subsequentemente, as pacientes foram submetidas a axilectomia dos níveis I, II e III (158) ou à técnica do linfonodo sentinela (23). Foram calculadas a sensibilidade, a especificidade e os valores preditivos positivo e negativo para cada parâmetro. Para a associação de parâmetros foi utilizada a árvore de decisão. Foram estabelecidos os valores de corte para as variáveis contínuas por meio da curva ROC. RESULTADOS: ao exame ultra-sonográfico foi identificado pelo menos um linfonodo axilar em 173 (96%) exames. O exame histológico detectou metástase linfonodal em 87 mulheres (48%). As melhores sensibilidades dos critérios morfológicos foram encontradas com o volume (62%), diâmetro ântero-posterior (62%) e local do centro ecogênico (56%). Embora a especificidade da invasão da gordura adjacente (100%), regularidade das margens (92%) e da ecotextura do parênquima (99%) tenham sido elevadas, a sensibilidade destes parâmetros foi muito baixa. Nenhum critério dopplervelocimétrico alcançou 50% de sensibilidade. A árvore de decisão selecionou a localização do centro ecogênico, a ecotextura do parênquima e a regularidade das margens como melhor associação de parâmetros. CONCLUSÃO: o estadiamento dos linfonodos axilares por método não invasivo ainda é um objetivo não alcançado no tratamento das pacientes com câncer de mama.
Resumo:
OBJETIVO: descrever os valores encontrados para o índice de resistência (IR), índice de pulsatilidade (IP) e relação sístole/diástole (S/D) das artérias renais fetais em gestações sem complicações entre a 22ª e a 38ª semana de gestação e avaliar se estes valores variam durante esse período. MÉTODOS: estudo observacional, no qual 45 fetos de gestações não-complicadas foram avaliados na 22ª, 26ª, 30ª, 34ª e 38ª semanas gestacional. Os exames ultra-sonográficos com Doppler foram feitos por um único observador que utilizou aparelho com transdutor de 4 a 7 MHz. Para a aquisição do traçado de velocidade das artérias renais, uma amostra, com tamanho entre 1 e 2 mm, foi posicionada no terço médio da artéria renal para avaliação através da ultra-sonografia com Doppler pulsado, sempre por um único observador. A avaliação do IR, do IP e da relação S/D das artérias renais (direita e esquerda) foi realizada a partir de três ondas consecutivas utilizando-se o modo automático. Para demonstrar diferença nos valores dos índices com a variação da idade gestacional, comparamos os valores obtidos nas diferentes idades gestacionais através do teste ANOVA com medidas repetidas no tempo (repeated measures ANOVA) com pós-teste de Tukey. RESULTADOS: Não houve diferença significativa entre a artéria renal direita e a esquerda quando se compararam o IR, o IP e a relação S/D. Entretanto, observou-se modificação dos valores destes parâmetros entre a 22ª semana (IR=0,9 ± 0,02; IP=2,44 ± 0,2; relação S/D=11,6 ± 2,2; média ± desvio padrão do valor médio da artéria renal direita e esquerda) e a 38ª semana (IR=0,8 ± 0,03; IP=2,1 ± 0,2; relação S/D=8,7 ± 2,3) de idade gestacional. CONCLUSÕES: os parâmetros avaliados (IR, IP e relação S/D) apresentam valores decrescentes entre a 22ª e a 38ª semana, sem diferença entre os lados direito e esquerdo do feto.
Resumo:
OBJETIVOS: Avaliar os padrões hemodinâmicos da artéria oftálmica, por meio da doplervelocimetria, em portadoras de diabetes mellitus gestacional (DMG), e comparar os achados com os obtidos em gestantes normais. MÉTODOS: Estudo prospectivo caso-controle que analisou os índices doplervelocimétricos das artérias oftálmicas. Foram constituídos dois grupos: um com 40 gestantes com diagnóstico de DMG e o outro por 40 gestantes normais. Foram incluídas gestantes com DMG segundo critérios da American Diabetes Association - 2012, com gravidez de 27 semanas até o termo, e excluídas gestantes hipertensas, em uso de drogas vasoativas ou com diagnóstico prévio de diabetes. O estudo foi realizado em um olho com transdutor linear de 10 MHz Sonoace 8000 Live Medison ®. As variáveis analisadas foram: índice de pulsatilidade (IP), índice de resistência (IR), razão entre picos de velocidade (RPV), pico de velocidade sistólica (PVS) e velocidade diastólica final (VDF). Para análise de normalidade das amostras foi empregado o teste de Lillefors, e os testes t de Student e Mann-Whitney, para comparação entre as médias e medianas conforme normalidade dos dados, e adotado nível de significância de 95%. RESULTADOS: As medianas e médias com desvio padrão das variáveis doplervelocimétricas da artéria oftálmica dos grupos de DMG e gestantes normais foram, respectivamente: IP=1,7±0,6 e 1,6±0,4 (p=0,7); IR=0,7 e 0,7 (p=0,9); RPV=0,5±0,1 e 0,5±0,1 (p=0,1); PVS=33,6 e 31,9 cm/seg (p=0,7); VDF=6,3 e 7,9 cm/seg (p=0,4). Não houve diferença significante entre as médias e medianas das variáveis analisadas entre os dois grupos de gestantes. CONCLUSÕES: Os padrões hemodinâmicos das artérias oftálmicas permaneceram inalterados no grupo de gestantes com DMG em relação ao grupo de gestantes normais, sugerindo que o tempo de exposição à doença durante a gestação é curto para causar vasculopatias importantes no território materno central.
Resumo:
O herpesvírus bovino tipo 5 (BoHV-5) é um agente importante de meningoencefalite em bovinos. Após replicação na mucosa nasal, acredita-se que o vírus invada o cérebro principalmente pela via olfatória. Para investigar a importância dessa via na patogenia da infecção neurológica em um modelo animal, coelhos recém-desmamados (30 dias) foram submetidos à ablação cirúrgica dos bulbos olfatórios (BOs) e posteriormente inoculados pela via intranasal (IN) ou no saco conjuntival (IC) com uma cepa altamente neurovirulenta do BoHV-5 (SV-507). Após inoculação IN, 10/10 coelhos no Grupo Controle (com BOs) desenvolveram enfermidade neurológica, com início dos sinais clínicos entre os dias 5 e 10 pós-inoculação (pi) (média de 7,5 dias); em contraste, no grupo submetido à ablação dos BOs (n=11), apenas um animal (9,1%) desenvolveu doença neurológica (início no dia 17pi). Administração de dexametasona aos animais sobreviventes (n=10) no dia 50 pi resultou em excreção viral em secreções nasais e/ou oculares por oito destes, demonstrando que o vírus foi capaz de atingir o gânglio trigêmeo (TG) durante a infecção aguda. Esses resultados demonstram que a rota olfatória representa a via principal, mas não única, de acesso ao cérebro de coelhos após inoculação IN. Para investigar o papel de uma segunda possível via de acesso, grupos de coelhos controle (n=12) ou submetidos à ablação dos BOs (n=12) foram inoculados no saco conjuntival (IC), após o qual o vírus poderia utilizar o ramo oftálmico do nervo trigêmeo para invadir o cérebro. Dez coelhos controle (83,3 %) desenvolveram doença neurológica após inoculação IC, com início dos sinais entre os dias 11 e 20 (média 15,3 dias). A ablação prévia dos BOs não afetou a freqüência ou o curso da doença neurológica nesse grupo: 10/12 coelhos (83,3 %) sem os BOs desenvolveram a doença neurológica, com os sinais iniciando entre os dias 9 e 15pi (média 12,7 dias). Esses resultados demonstram que tanto a via olfatória como a trigeminal podem servir de acesso para o BoHV-5 invadir o cérebro de coelhos inoculados experimentalmente, dependendo da via de inoculação. Inoculação IN resulta em um transporte rápido e eficiente pela via olfatória; com a via trigeminal servindo de acesso mais lento e menos eficiente. Inoculação IC resulta em transporte e invasão eficientes, porém mais tardios, provavelmente pela via trigeminal.
Resumo:
An alkali-insoluble fraction 1 (F1), which contains mainly ß-glucan isolated from the cell wall of Histoplasma capsulatum, induces eosinophil recruitment into the peritoneal cavity of mice. The present study was carried out to determine the participation of interleukin-5 (IL-5) in this process. Inbred C57BL/6 male mice weighing 15-20 g were treated ip with 100 µg of anti-IL-5 monoclonal antibody (TRFK-5, N = 7) or an isotype-matched antibody (N = 7), followed by 300 µg F1 in 1 ml PBS ip 24 h later. Controls (N = 5) received only 1 ml PBS. Two days later, cells from the peritoneal cavity were harvested by injection of 3 ml PBS and total cell counts were determined using diluting fluid in a Neubauer chamber. Differential counts were performed using Rosenfeld-stained cytospin preparations. The F1 injection induced significant (P < 0.01) leukocyte recruitment into the peritoneal cavity (8.4 x 10(6) cells/ml) when compared with PBS alone (5.5 x 10(6) cells/ml). Moreover, F1 selectively (P < 0.01) induced eosinophil recruitment (1 x 10(6) cells/ml) when compared to the control group (0.07 x 10(6) cells/ml). Treatment with TRFK-5 significantly (P < 0.01) inhibited eosinophil recruitment (0.18 x 10(6) cells/ml) by F1 without affecting recruitment of mononuclear cells or neutrophils. We conclude that the F1 fraction of the cell wall of H. capsulatum induces peritoneal eosinophilia by an IL-5-dependent mechanism. Depletion of this cytokine does not have effect on the recruitment of other cell types induced by F1.
Resumo:
Parkinson's disease, a major neurodegenerative disorder in humans whose etiology is unknown, may be associated with some environmental factors. Nocardia otitidiscaviarum (GAM-5) isolated from a patient with an actinomycetoma produced signs similar to Parkinson's disease following iv injection into NMRI mice. NMRI mice were infected intravenously with a non-lethal dose of 5 x 10(6) colony forming units of N. otitidiscaviarum (GAM-5). Fourteen days after bacterial infection, most of the 60 mice injected exhibited parkinsonian features characterized by vertical head tremor, akinesia/bradykinesia, flexed posture and postural instability. There was a peak of nocardial growth in the brain during the first 24 h followed by a decrease, so that by 14 days nocardiae could no longer be cultured. At 24 h after infection, Gram staining showed nocardiae in neurons in the substantia nigra and occasionally in the brain parenchyma in the frontal and parietal cortex. At 21 days post-infection, tyrosine hydroxylase immunolabeling showed a 58% reduction of tyrosine hydroxylase in the substantia nigra, and a 35% reduction of tyrosine hydroxylase in the ventral tegmental region. Dopamine levels were reduced from 110 ± 32.5 to 58 ± 16.5 ng/mg protein (47.2% reduction) in brain from infected mice exhibiting impaired movements, whereas serotonin levels were unchanged (191 ± 44 protein in control and 175 ± 39 ng/mg protein in injected mice). At later times, intraneuronal inclusion bodies were observed in the substantia nigra. Our observations emphasize the need for further studies of the potential association between Parkinson's disease or parkinsonism-like disease and exposure to various nocardial species.