Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
1.
Pediatr Emerg Care ; 37(7): 365-370, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30211837

RESUMO

OBJECTIVES: The effectiveness of Japanese helicopter emergency medical services (HEMS) and interventions at the scene is not clear as regard children. For effective use of HEMS at the clinical scene, we need to clarify the characteristics of pediatric patients cared for by HEMS. Therefore, the objective of this study was to describe the characteristics of pediatric scene flights and to describe the procedures performed on the patients. METHODS: This was a retrospective cohort study based on the database for children aged younger than 18 years who were cared for by physician-staffed HEMS of Ibaraki prefecture, in Japan. We reviewed the database for air medical transports conducted at our institution from July 2010 to December 2016. RESULTS: During the 6.5-year period, the Ibaraki HEMS attended to 288 children. The median age of the children was 11 (interquartile range, 5-14) years. Of the total, 196 (68.1%) of the children had trauma-related injuries. The head was the most common site of significant injuries (12.4%). The most common cause of nontrauma incidents was seizure (9.0%). In 65.9% of the patients, the injury or illness was of mild or moderate severity at the scene. An intervention was applied at the scene in 76.0% of the cases: 75.1%, intravenous route; 6.9%, intubation; and 13.4%, drug administration. Of those patients, 29.1% were discharged from the emergency department. In-hospital mortality accounted for 1.5% (n = 2) of the cases. CONCLUSIONS: Although the condition at the scene of most of the pediatric patients transported by the physician-staffed HEMS was not severe, an intervention was frequently applied from the scene. Improving the dispatch criteria and monitoring compliance are needed for appropriate use of HEMS.


Assuntos
Resgate Aéreo , Serviços Médicos de Emergência , Médicos , Adolescente , Aeronaves , Criança , Pré-Escolar , Humanos , Estudos Retrospectivos
2.
Asian J Neurosurg ; 17(4): 638-641, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36570747

RESUMO

Rapid advances in emergent mechanical thrombectomy have resulted in a higher occurrence of arterial perforations during neurointerventions. Here, we report a case of internal carotid artery (ICA) perforation during mechanical thrombectomy in a 78-year-old man with a left middle cerebral artery occlusion. The ICA was perforated by a microcatheter during thrombectomy, forming a direct carotid-cavernous fistula. A two-stage drainer occlusion was conducted because of cortical venous reflex aggravation and ocular symptoms. Here, we report the perforation details and treatment, adding to evidence that ICA perforation with the microcatheter body is a concern during mechanical thrombectomy.

3.
World J Pediatr Surg ; 5(2): e000350, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36474514

RESUMO

Objective: The Japan Coma Scale (JCS) is widely used in clinical practice to evaluate levels of consciousness in Japan. There have been several studies on the usefulness of JCS in adults. However, its usefulness in evaluating children has not been reported. Therefore, this study aimed to assess the usefulness of the JCS for the prediction of mortality in children. Methods: This is a multicenter cohort study which used data from a national trauma registry (Japan Trauma Data Bank). This study included patients under 16 years of age who were treated between 2004 and 2015.The primary outcome measure was in-hospital mortality. Two models were used to examine each item of the Glasgow Coma Scale (GCS) and the JCS. Model A included the discrete levels of each index. In model B, data regarding age, sex, vital signs on arrival to hospital, the Injury Severity Score, and blunt trauma were added to each index. The effectivity of the JCS score was then evaluated using the area under the curve (AUC) for discrimination, a calibration plot, and the Hosmer-Lemeshow test for calibration. Results: A total of 9045 patients were identified. The AUCs of the GCS and JCS were 0.929 (95% confidence interval (CI) 0.904 to 0.954) and 0.930 (95% CI 0.906 to 0.954) in model A and 0.975 (95% CI 0.963 to 0.987) and 0.974 (95% CI 0.963 to 0.985) in model B, respectively. The results of the Hosmer-Lemeshow test were 0.00 (p=1.00) and 0.00 (p=1.00) in model A and 4.14 (p=0.84) and 8.55 (p=0.38) in model B for the GCS and JCS, respectively. Conclusions: We demonstrated that the JCS is as valid as the GCS for predicting mortality. The findings of this study indicate that the JCS is a useful and relevant tool for pediatric trauma care and future research.

4.
Neurol Med Chir (Tokyo) ; 61(9): 521-527, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34121049

RESUMO

Various approaches have been tried for acute ischemic stroke (AIS) treatment to shorten the time from onset to recanalization. MRI positioning scanning (PS), which must be taken before any MRI sequences, was examined whether it can detect cerebral large vessel occlusion. A total of 68 consecutive patients with AIS who underwent MRI and were treated with intravenous recombinant tissue plasminogen activator or mechanical thrombectomy at our hospital were retrospectively included in this study. Occluded vessels were identified on the axial or coronal views of PS images, and these images were compared with 3D time-of-flight MRA and digital subtraction angiogram. The sensitivities, positive predictive values (PPVs), and negative predictive values (NPVs) for internal carotid artery (ICA), the proximal M1, distal M1, and M2 segment of the middle cerebral artery occlusion were assessed, and the number of PS slices was assessed. The sensitivities of the axial slices for ICA, proximal M1, distal M1, and M2 occlusion were 62%, 21%, 35%, and 86%, respectively. The PPVs of the axial slices for ICA, proximal M1, distal M1, and M2 occlusion were 81%, 88%, 100%, and 97%, respectively, and the NPVs of the axial slices for ICA, proximal M1, distal M1, and M2 occlusion were 94%, 90%, 86%, and 100%, respectively. The detection rate for the ICA was significantly higher with three axial slices (91%) than with two slices (47%) (p <0.01). MRI PS is warranted to be referred to detect large cerebral vessel occlusion.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Acidente Vascular Cerebral , Isquemia Encefálica/diagnóstico por imagem , Humanos , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Imageamento por Ressonância Magnética , Estudos Retrospectivos , Acidente Vascular Cerebral/diagnóstico por imagem , Trombectomia , Ativador de Plasminogênio Tecidual , Resultado do Tratamento
5.
Interv Neuroradiol ; 27(5): 672-676, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33715499

RESUMO

We herein report a rare case of a patient with a clival diploic vein arteriovenous fistula (AVF) associated with a posterior condylar canal AVF and discuss the radiological features of clival diploic vein AVF during decision-making on treatment strategies. A 69-year-old male patient with one-year history of pulsatile tinnitus was evaluated with magnetic resonance angiography, which revealed a dilated venous structure. Digital subtraction angiography revealed AVFs located in the clivus and posterior condylar canal. The clival diploic vein AVF was fed by the right internal maxillary artery and the petrous branch of middle meningeal artery and shed to the posterior condylar canal only through an intraosseous vein in the jugular tubercle. Although a catheter could not be navigated into the venous pouch in the clivus, the AVFs were successfully obliterated by transvenous embolization of the venous pouch in the posterior condylar canal.


Assuntos
Fístula Arteriovenosa , Embolização Terapêutica , Idoso , Angiografia Digital , Fístula Arteriovenosa/terapia , Fossa Craniana Posterior/diagnóstico por imagem , Humanos , Masculino , Artérias Meníngeas
6.
Surg Neurol Int ; 11: 120, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32494395

RESUMO

BACKGROUND: While recent randomized clinical trials have shown the efficacy of mechanical thrombectomy for acute large vessel anterior cerebral occlusion, cases in patients with a subarachnoid hemorrhage (SAH) were excluded from the study. CASE DESCRIPTION: A 58-year-old man presented with a SAH as a result of a ruptured middle cerebral artery aneurysm. Coil embolization was performed, and a right intracranial angiography showed remnants of an aneurysmal neck. However, the following angiography also revealed a thromboembolic complication that occurred in the same territory as the ruptured aneurysm. The patient underwent a rescue mechanical thrombectomy under the working projection. We deployed a retrieval stent without covering the aneurysmal neck. The occluded vessel was recanalized without any hemorrhagic complication. Due to minimal intracerebral infarction, the patient had good outcomes. CONCLUSION: Mechanical thrombectomy is a useful option to retrieve a clot from an occluded intracranial vessel located near a ruptured aneurysm. Approaching the clot at the working projection is important to ensure safety in the setting of a ruptured aneurysm.

7.
PLoS One ; 15(8): e0237192, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32785294

RESUMO

BACKGROUND: Helicopter emergency medical services' (HEMS) effectiveness for pediatric trauma patients remains unclear. We aimed to examine the relation between HEMS and reduced mortality in pediatric trauma patients. METHODS: This retrospective cohort study utilized data from the Japan Trauma Data Bank, a national multicenter clinical trauma database. Participants were aged <18 years, admitted between 2004 and 2015, and transported from the scene to the hospital by HEMS or ground emergency medical services (GEMS). We used a standardized mortality ratio (SMR) weight method, and fitted a marginal structural model to adjust for measured confounders. The SMR weight was calculated using the estimation of the propensity scores. A logistic regression model was used with the baseline independent variables to estimate the propensity score. RESULTS: Overall, 5,947 patients were identified in our study: 453 were transported by HEMS and 5,494 by GEMS. The mean injury severity score in the HEMS group was significantly higher than that in the GEMS group17.0 (Standard deviation = 11.0) vs 12.2 (Standard deviation = 9.2), p < .001. In-hospital mortality was higher in the HEMS group than that in the GEMS group in the unadjusted analysis (3.8% vs 1.3%, respectively; p < .001). After adjusting for covariates, HEMS transport was not associated with reduced hospital mortality. (odds ratio = 0.82, 95% confidence interval = 0.42-1.58). CONCLUSIONS: HEMS was not associated with reduced mortality among pediatric trauma patients compared with GEMS in this nationwide study. Further investigation is necessary to determine who clearly benefits from HEMS as compared to GEMS.


Assuntos
Resgate Aéreo , Aeronaves , Serviços Médicos de Emergência/métodos , Mortalidade Hospitalar , Transporte de Pacientes/métodos , Ferimentos e Lesões/mortalidade , Adolescente , Criança , Pré-Escolar , Bases de Dados Factuais , Feminino , Humanos , Lactente , Recém-Nascido , Escala de Gravidade do Ferimento , Japão , Masculino , Mortalidade , Estudos Retrospectivos , Fatores de Tempo
8.
World Neurosurg ; 132: e812-e819, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31404689

RESUMO

BACKGROUND: Few reports have focused on chronic subdural hematoma (CSDH) in the very elderly, who have lived beyond average life expectancy. Our aim is to appraise treatment outcomes of burr-hole craniotomy for CSDH in the elderly, focusing on cure, recurrence, and complications. METHODS: Fifty patients ≤79 years of age (group A) and 73 patients ≥80 years of age (group B) were studied. Recurrence was defined as requiring reoperation for hematoma regrowth or symptomatic failure. A cure was regarded as having been achieved in the absence of hematoma on postoperative computed tomography. Complications were defined as any harmful event related to the treatment procedure for CSDH. RESULTS: Cure was documented in 31 patients in group A (63%) and 24 patients in group B (33%) (P = 0.0017). Median intervals to cure were 2.76 and 3.73 months, respectively (P = 0.06). Cumulative cure rates were 51%/76% and 36%/59%, respectively, at the sixth/twelfth postoperative months. Recurrence was documented in 2 patients (4%) and 11 patients (15%), respectively (P = 0.07). Median intervals to recurrence were 0.81 and 1.25 months, respectively (P = 0.049). Cumulative recurrence-free rates were 96%/92% and 87%/75%, respectively, at the third/sixth postoperative months. Complications were observed in 2 patients (4%) and 4 patients (5%), respectively (P = 1.00). CONCLUSIONS: With advancing age, CSDH might show a greater tendency to recur and a longer time is required to achieve a cure. However, complications developed only in high-risk patients. Thus, surgical treatment for CSDH in elderly patients, even those who have lived beyond life expectancy, might provide acceptably effective results.


Assuntos
Hematoma Subdural Crônico/cirurgia , Trepanação/métodos , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Seguimentos , Hematoma Subdural Crônico/mortalidade , Humanos , Estimativa de Kaplan-Meier , Expectativa de Vida , Masculino , Complicações Pós-Operatórias/epidemiologia , Recidiva , Reoperação/estatística & dados numéricos , Estudos Retrospectivos , Resultado do Tratamento , Trepanação/mortalidade
9.
J Clin Neurosci ; 32: 41-6, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27523585

RESUMO

We present a retrospective analysis of endovascular treatments for posterior cerebral artery (PCA) aneurysms and discuss the susceptibility of a fetal-type PCA to vascular insufficiency after parent artery occlusion. Among 1207 aneurysms treated with endovascular therapy between March 1997 and March 2013 in our institution, 10 patients (0.8%) presented PCA aneurysms. The principal strategy was to employ selective coil embolization for the aneurysm. However, in certain cases of fusiform or dissecting aneurysms, we performed parent artery occlusion with coils. Clinical and radiological data were collected from hospital charts and evaluated retrospectively. The mean age was 52.7±15.6years (range, 12-65years). Five patients (50%) were admitted with a subarachnoid hemorrhage, and one patient presented with slowly developing paralysis. The remaining four patients were diagnosed incidentally. Five patients underwent selective coil embolization, and five patients underwent parent artery occlusion. All endovascular therapies were successfully performed. However, two patients in the parent artery occlusion group suffered cerebral infarction, and both patients exhibited a fetal-type PCA. The remaining three patients in the parent artery occlusion group exhibited an adult-type PCA and did not suffer a cerebral infarction. Endovascular treatment with either selective coil embolization or parent artery occlusion is safe and effective as the long as the anatomical type of the PCA is considered. Patients with a fetal-type PCA may develop vascular insufficiency upon parent artery occlusion. Neurosurgeons should attempt to preserve the parent artery using a flow-diverting stent or stent-assisted technique for a fetal-type PCA aneurysm.


Assuntos
Embolização Terapêutica/efeitos adversos , Aneurisma Intracraniano/terapia , Artéria Cerebral Posterior/diagnóstico por imagem , Adolescente , Adulto , Idoso , Angiografia Cerebral , Criança , Feminino , Humanos , Aneurisma Intracraniano/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Posterior/patologia , Stents/efeitos adversos
11.
Anticancer Res ; 23(6D): 5231-5, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14981995

RESUMO

BACKGROUND: In boron neutron capture therapy, blood boron concentration is the key factor to calculate radiation dose, however, blood sampling is difficult during neutron irradiation. MATERIALS AND METHODS: The prediction of blood boron concentrations for BNCT treatment planning has been prospectively investigated using patient data obtained at first craniotomy after the infusion of a low dose of sodium undecahydroclosododecaborate. RESULTS: The boron biodistribution data showed a biexponential pharmacokinetic profile. If the final boron concentration at 6 or 9 hours after the end of the infusion is within the 95% confidence interval of the prediction, direct prediction from biexponential fit will reduce the error of blood boron concentrations during irradiation to around 6%. CONCLUSION: Actual boron concentrations during BNCT were reasonably and accurately predictable from the test data.


Assuntos
Astrocitoma/sangue , Terapia por Captura de Nêutron de Boro , Boro/sangue , Neoplasias Encefálicas/sangue , Glioblastoma/sangue , Adulto , Idoso , Astrocitoma/radioterapia , Astrocitoma/cirurgia , Boro/farmacocinética , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/cirurgia , Terapia Combinada , Feminino , Glioblastoma/cirurgia , Glioblastoma/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Distribuição Tecidual
12.
Resuscitation ; 85(3): 315-9, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24291510

RESUMO

OBJECTIVES: Bystander-initiated cardiopulmonary resuscitation (CPR) has been reported to increase the possibility of survival in patients with out-of-hospital cardiopulmonary arrest (OHCA). We evaluated the effects of CPR instructions by emergency medical dispatchers on the frequency of bystander CPR and outcomes, and whether these effects differed between family and non-family bystanders. METHODS: We conducted a retrospective cohort study, using Utstein-style records of OHCA taken in a rural area of Japan between January 2004 and December 2009. RESULTS: Of the 559 patients with non-traumatic OHCA witnessed by laypeople, 231 (41.3%) were given bystander CPR. More OHCA patients received resuscitation when the OHCA was witnessed by non-family bystanders than when it was witnessed by family members (61.4% vs. 34.2%). The patients with non-family-witnessed OHCA were more likely to be given conventional CPR (chest compression plus rescue breathing) or defibrillation with an AED than were those with family-witnessed OHCA. Dispatcher instructions significantly increased the provision of bystander CPR regardless of who the witnesses were. Neurologically favorable survival was increased by CPR in non-family-witnessed, but not in family-witnessed, OHCA patients. No difference in survival rate was observed between the cases provided with dispatcher instructions and those not provided with the instructions. CONCLUSIONS: Dispatcher instructions increased the frequency of bystander CPR, but did not improve the rate of neurologically favorable survival in patients with witnessed OHCA. Efforts to enhance the frequency and quality of resuscitation, especially by family members, are required for dispatcher-assisted CPR.


Assuntos
Reanimação Cardiopulmonar/normas , Sistemas de Comunicação entre Serviços de Emergência , Família , Parada Cardíaca Extra-Hospitalar/terapia , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento
14.
Neurol Med Chir (Tokyo) ; 52(9): 691-4, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23006889

RESUMO

Sufficient bone decompression of osteophytes is important for positive functional outcomes in anterior cervical spine surgery. Achieving good alignment and bone fusion in anterior cervical decompression and fusion requires a bone graft bed of the optimum size and shape. We have developed a stainless steel instrument named the anterior fusion spinal fork, which is designed to aid in accurately drilling the bone cavity, thus enabling selection of the correct size of bone graft or bone graft substitutes. The device has an open design with 4 prongs, and resembles a three-dimensional fork. This instrument assists in guiding the direction of drilling, and marking the drilling point of the graft cavity with pyoctanin markers. We have used this instrument in 40 cases of anterior cervical spine surgery using the modified Smith-Robinson procedure since March 2000. This simple instrument allowed us to design and construct a bone graft cavity of the correct size and shape for iliac bone graft or bone graft substitutes for anterior cervical spine surgery.


Assuntos
Transplante Ósseo/instrumentação , Vértebras Cervicais/cirurgia , Descompressão Cirúrgica/métodos , Discotomia/métodos , Compressão da Medula Espinal/cirurgia , Fusão Vertebral/métodos , Adulto , Idoso , Vértebras Cervicais/diagnóstico por imagem , Corantes , Durapatita , Desenho de Equipamento , Feminino , Transtornos Neurológicos da Marcha/etiologia , Violeta Genciana , Humanos , Hipestesia/etiologia , Masculino , Pessoa de Meia-Idade , Lesões do Pescoço/complicações , Lesões do Pescoço/cirurgia , Próteses e Implantes , Radiografia , Estudos Retrospectivos , Compressão da Medula Espinal/etiologia , Osteofitose Vertebral/complicações , Osteofitose Vertebral/diagnóstico por imagem , Osteofitose Vertebral/cirurgia , Espondilose/complicações , Espondilose/cirurgia
15.
Hum Exp Toxicol ; 29(5): 427-9, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20068013

RESUMO

A 27-year-old female nurse intravenously injected 5 mL of cigarette soakage solution that contained approximately 5.7 mg nicotine, in a suicidal attempt. Clinical manifestations consisted of nausea, palpitation, abdominal pain, repeated vomiting, and diarrhea. She remained fully conscious during this episode. About 7 hours later, she visited emergency department on foot and received fluid infusion for dehydration. She fully recovered at night of the day. This is the first documented report of acute nicotine poisoning due to intravenous injection of cigarette soakage in humans. Signs and symptoms appeared immediately after the injection, but this case seemed to be relatively mild in terms of clinical manifestation. The elimination half-life of nicotine seems to be short, that is, less than 1 hour. Therefore, if initial treatment is appropriate and the patient can survive acute phase of nicotine poisoning, prognosis is good.


Assuntos
Nicotiana/química , Nicotina/intoxicação , Intoxicação por Plantas/etiologia , Adulto , Feminino , Hidratação , Meia-Vida , Humanos , Injeções Intravenosas , Nicotina/farmacocinética , Extratos Vegetais/química , Extratos Vegetais/farmacocinética , Extratos Vegetais/intoxicação , Intoxicação por Plantas/fisiopatologia , Intoxicação por Plantas/terapia , Tentativa de Suicídio
16.
In. Hamada, M, ed; O'Rourke, T, ed. Proceedings from the Sixth Japan-U.S. Workshop on Earthquake Resistant Design of Lifeline Facilities and Countermeasures Against Soil Liquefaction. Buffalo, NY, U.S. National Center for Earthquake Engineering Research, Sep. 1996. p.275-88, ilus, tab.
Monografia em En | Desastres | ID: des-9698

RESUMO

Very severe lateral flow occurred in the liquefied ground behind quay walls during the 1995 Hyogoken-nambu (Kobe) earthquake. Shaking table tests were conducted under several conditions to study the mechanism of the lateral flow. A soil container with a model quay wall and a model pile was used. The model quay wall was moved quickly or slowly just after the occurrence of liquefaction. Displacement of the top of the pile was affected by the speed of the movement of the wall and soil density. The effectiveness of densification of the ground behind the quay wall in preventing lateral flow was also studied.(AU)


Assuntos
Engenharia , Solo , Métodos , Terremotos , Japão , 28574
17.
In. U.S. National Center for Earthquake Engineering Research (NCEER). Proceedings from the fourth Japan-U.S. workshop on earthquake resistant design of lifeline facilities and countermeasures for soil liquefaction. New York, U.S. National Center for Earthquake Engineering Research (NCEER), Aug. 1992. p.453-63, ilus. (Technical Report NCEER, 1, 92-0019).
Monografia em En | Desastres | ID: des-7937

RESUMO

In Japan, everyday life would be seriously affected by damage to the infrastructure resulting from an earthquake, since most lifeline facilities are buried. Given those circunstances, studies of the damage caused to underground structures due to liquefaction have began over the past few years. However, most studies have concentrated on the behavior of buried structures in liquefied ground, with few taking into consideration the process by which the ground is liquefied or the large permanent displacements produced by liquefaction. Accordingly, we have traced the mechanism of damage to lifeline facilities, specifically buried pipelines, with the lapse of time, based on knowledge obtained from past experimental results. We carried out stress analysis on buried pipelines during the liquefaction process and looked for correspondence between the analytical results and the temporally equivalent results of effective stress analysis.(AU)


Assuntos
Terremotos , Tubulações , 28574 , Japão , Pesquisa
18.
In. Hamada, Masanori, ed; O'Rourke, T. D., ed. Proceedings from the fourth Japan-U.S. Workshop on Earthquake Resistant Design of Lifeline Facilities and Countermeasures for Soil Liquefaction. New York, U.S. National Center for Earthquake Engineering Research (NCEER), Aug. 12 1992. p.621-37, ilus, tab. (Technical Report NCEER, 92-0019, 92-0019).
Monografia em En | Desastres | ID: des-7949

RESUMO

We carried oiut several experiments to examine the adaptability of a sensor. From those, the water elevates higher as the pore water pressure developed in the soil is increases, and the two variables nearly have a proportionate relation each other. Then, we can roughly estimate the occurrence and degree of liquefaction if we measure the water level in the pipe of "Liquefaction Sensor".(AU)


Assuntos
Terremotos , 34661 , Solo , Engenharia , Métodos
19.
In. U.S. National Center for Earthquake Engineering Research (NCEER). Proceedings from the fifth U.S.-Japan workshop on earthquake resistant design of lifeline facilities and countermeasures against soil liquefaction. Buffalo, N.Y., U.S. National Center for Earthquake Engineering Research (NCEER), 1994. p.181-98, ilus. (Technical Report NCEER, 94-0026).
Monografia em En | Desastres | ID: des-7459

RESUMO

Behavior of sand after liquefaction is discussed and formuled. Material properties that are usually assumed constant, such as internal friction angle, is ahown to change due to cyclic loading causing liquefaction. It is also shown that regions with very small stiffness appears by the cyclic loading. They may expand several ten percents, which causes liquefaction-induced large permanent displacement. A simlified model is introduced and improved so as to be able to take into new features such as change of material property and appearance of low stiffness region. The agreement of the numerical calculation and test are very good. Future research needs for evaluating the amount of liquefaction-induced permanent displacement more precisely are also pointed out.(AU)


Assuntos
Solos Arenosos , Mecânica dos Solos , 24975 , Engenharia
20.
In. U.S. National Center for Earthquake Engineering Research (NCEER). Proceedings from the fifth U.S.-Japan workshop on earthquake resistant design of lifeline facilities and countermeasures against soil liquefaction. Buffalo, N.Y., U.S. National Center for Earthquake Engineering Research (NCEER), 1994. p.665-77, ilus. (Technical Report NCEER, 94-0026).
Monografia em En | Desastres | ID: des-7490

RESUMO

Many manholes and sewage pipes were floated due to liquefaction during the 1993 Kushiro-oki earthquake in Japan. To study the mechanism of the floatation, several shaking table tests were carried out under several conditions of soil densities, specific gravities of pipes, water levels and diameters of pipes. Tests were also conducted on the model grounds in which a trench was excavated and then backfilled with loose sands. Test results show that the speed and the height of floatation are affected by soil density, the specific gravity of the pipe or manhole, water level, and width and depth of the trench.(AU)


Assuntos
Terremotos , Tubulações , Águas Residuárias , Japão , Solos Saturados
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA