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2.
Materials (Basel) ; 16(6)2023 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-36984372

RESUMO

This study proposed wavelet-based approaches to characterise random vibration road excitations for durability prediction of coil springs. Conventional strain-life approaches require long computational time, while the accuracy of the vibration fatigue methods is unsatisfactory. It is therefore a necessity to establish an accurate fatigue life prediction model based on vibrational features. Wavelet-based methods were applied to determine the low-frequency energy and multifractality of road excitations. Strain-life models were applied for fatigue life evaluation from strain histories. ANFIS modelling was subsequently adopted to associate the vibration features with the fatigue life of coil springs. Results showed that the proposed wavelet-based methods were effective to determine the signal energy and multifractality of vibration signals. The established vibration-based models showed good fatigue life conservativity with a data survivability of more than 90%. The highest Pearson coefficient of 0.955 associated with the lowest RMSE of 0.660 was obtained by the Morrow-based model. It is suggested that the low-frequency energy and multifractality of the vibration signals can be used as fatigue-related features in life predictions of coil springs under random loading. Finally, the proposed model is an acceptable fatigue life prediction method based on vibration features, and it can reduce the dependency on strain data measurement.

3.
Clin Hemorheol Microcirc ; 83(3): 207-215, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36565106

RESUMO

BACKGROUND: Venous malformations tend to retain their slow-flow behavior, even in progressive disease or regression following therapy. OBJECTIVE: The aim of this study is to analyze the development of acquired hemodynamic relevant arterio-venous fistulae in patients with slow-flow malformations. METHODS: This study is a retrospective analysis based on a consecutive local registry at a tertiary care Interdisciplinary Center for Vascular Anomalies. Patients with venous malformations and development of secondary arterio-venous fistulae were included. Indications for therapy of the vascular malformation were based on patients' symptoms and complications. The following endpoints were of clinical interest and were assessed: origin of development of arteriovenous fistula, development of secondary comorbidities as a result of the vascular malformation. For analysis we focused on descriptive statistics. RESULTS: Out of 1213 consecutive patients with vascular malformations, in 6 patients perfusion changed from slow flow to arterio-venous fast-flow patterns. Four patients developed the fistula after local trauma in the area of the malformation, the other 2 patients developed the fistula due to progression of the disease and recurrent thrombophlebitis. These 2 patients had no trauma or interventions at the time of arterio-venous fistula development. CONCLUSIONS: Acquired arterio-venous fast-flow fistula in patients with slow flow vascular malformation is very rare and might be a result of local trauma or the progression of the disease with recurrent thrombophlebitis. Specific evidence-based treatment options for these patients do not exist.


Assuntos
Fístula Arteriovenosa , Tromboflebite , Malformações Vasculares , Humanos , Estudos Retrospectivos , Malformações Vasculares/complicações , Fístula Arteriovenosa/complicações , Tromboflebite/complicações
4.
Artigo em Inglês | WPRIM (Pacífico Ocidental) | ID: wpr-780670

RESUMO

@#While driving, a driver is required to control the steering wheel to change direction. The driver’s muscles of the upper limbs and shoulders are involved in such a task. Therefore, an assessment of the driver’s physiology according to certain condition is necessary to improve driving comfort and safety. This study aims to investigate the driver’s Deltoid Anterior (DA) muscle activity while operating the steering wheel. Eleven test subjects were recruited for an experiment using a car simulator. They were required to remain in the car seat and perform the task of steering the wheel. Surface electromyography (SEMG) was used to record each subject’s muscle contraction while turning the steering wheel to the right and left by several degrees. According to the findings, 45 degrees turning recorded the highest Root mean Square (RMS) value for DA. In addition, DA muscle activation increased with more degrees turning.

5.
Radiologe ; 57(4): 296-301, 2017 Apr.
Artigo em Alemão | MEDLINE | ID: mdl-28255791

RESUMO

BACKGROUND AND METHOD: Incidental cardiovascular findings are a frequent phenomenon in computed tomography (CT) examinations. As the result of a dedicated PubMed search this article gives a systemic overview of the current literature on the most important incidental cardiovascular findings, their prevalence and clinical relevance. RESULTS: The majority of incidental cardiovascular findings are of only low clinical relevance; however, highly relevant incidental findings, such as aortic aneurysms, thromboses and thromboembolic events can also occasionally be found, especially in oncology patients. CONCLUSION: The scans from every CT examination should also be investigated for incidental findings as they can be of decisive importance for the further clinical management of patients, depending on their clinical relevance.


Assuntos
Doenças Cardiovasculares/diagnóstico por imagem , Achados Incidentais , Tomografia Computadorizada por Raios X , Doenças Cardiovasculares/epidemiologia , Humanos , Exame Físico , Prevalência
6.
Radiologe ; 57(3): 217-230, 2017 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-28180915

RESUMO

The term nonthrombotic pulmonary embolism (NTPE) is defined as embolization of pulmonary arteries caused by foreign bodies (e. g. detached catheter fragments), biological substances (e. g. septic thrombus) or exogenous substances (e. g. gas). The frequency of NTPE is underestimated. Symptoms can cover the spectrum from undetectable to sudden death. In addition to mechanical obstruction of the pulmonary arteries, some NTPEs trigger an inflammatory cascade that causes deterioration of vascular, pulmonary and cardiac function. Radiological imaging in combination with the medical history of patients is sufficient to identify most NTPEs with certainty. The aim of this article is to make readers aware of the symptoms, frequency, relevance, classification, pathophysiology, laboratory findings and radiological findings of the most frequent forms of NTPE. The spectrum of forms presented here includes pulmonary embolisms due to foreign bodies (intravascular, intracorporeal and extracorporeal), amniotic fluid, endogenous tissue, fat, tumors, septic thrombi, hydatids, cement, metallic mercury, gas, silicone and particles.


Assuntos
Artéria Pulmonar , Embolia Pulmonar/etiologia , Embolia Aérea/complicações , Corpos Estranhos/complicações , Humanos , Trombose/complicações
8.
Br J Radiol ; 87(1041): 20140185, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25004949

RESUMO

OBJECTIVE: The purpose of this study was to identify the frequency and grading of non-osseous incidental findings (NOIF) in non-contrast whole-body low-dose CT (LDCT) in patients with multiple myeloma. METHODS: In the time period from 2010 to 2013, 93 patients with multiple myeloma were staged by non-contrast whole-body LDCT at our radiological department. LDCT images were analysed retrospectively for NOIF, which also included unsuspected extramedullary manifestation of multiple myeloma. All NOIF were classified as major or clinically significant, moderate or possibly clinically significant and minor or not clinically significant. Medical records were analysed regarding further investigation and follow-up of the identified NOIF. RESULTS: In the 93 patients, 295 NOIF were identified (on average, 3.2 NOIF per patient). Most of the NOIF (52.4%) were not clinically significant, 25.8% of the NOIF were possibly clinically significant and 21.8% of the NOIF were clinically significant. Clinically significant NOIF were investigated further by CT after intravenous administration of contrast medium and/or by ultrasound or MRI. In 34 of these cases, extramedullary relapse of myeloma, occult carcinoma or infectious/septic incidental findings were diagnosed (11.5% of all NOIF). In the remaining 10.3% of the NOIF classified as clinically significant, various benign lesions were diagnosed. CONCLUSION: LDCT detected various non-osseous lesions in patients with multiple myeloma. 36.6% of the patients had clinically significant NOIF. Therefore, LDCT examinations in patients with multiple myeloma should be evaluated carefully for the presence of NOIF. ADVANCES IN KNOWLEDGE: LDCT identified several NOIF. A total of 36.6% of patients with multiple myeloma had clinically significant NOIF. Radiologists should analyse LDCT examinations in patients with multiple myeloma not only for bone lesions, but also for lesions in other organs.


Assuntos
Achados Incidentais , Mieloma Múltiplo/diagnóstico por imagem , Mieloma Múltiplo/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Comorbidade , Meios de Contraste , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Doses de Radiação , Estudos Retrospectivos , Fatores de Tempo , Tomografia Computadorizada por Raios X/métodos
13.
Genes Immun ; 14(1): 42-51, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23151487

RESUMO

Two CCL3 haplotypes (HapA1 and Hap-A3) and two polymorphic positions shared by the haplotypes (Hap-2SNP (single nucleotide polymorphism)) were investigated together with CCL3L copy number (CN), for their role in HIV-1 disease. Hap-A1 was associated with protection from in utero HIV-1 infection: exposed uninfected (EU) infants had higher representation of wild type (WT)/Hap-A1 than infected infants (excluding intrapartum (IP)-infected infants), which maintained significance post maternal Nevirapine (mNVP) and viral load (MVL) correction (P=0.04; odds ratio (OR)=0.33). Mother-infant pair analyses showed the protective effect of Hap-A1 is dependent on its presence in the infant. Hap-A3 was associated with increased IP transmission: WT/Hap-A3 was increased in IP-transmitting vs non-transmitting (NT) mothers, and remained significant post mNVP and MVL correction (P=0.02; OR=3.50). This deleterious effect of Hap-A3 seemed dependent on its presence in the mother. Hap-2SNP was associated with lower CD4 count in the NT mothers (P=0.03). CCL3 Hap-A1 was associated with high CCL3L CN in total (P=0.001) and EU infants (P=0.006); the effect was not additive, however, having either Hap-A1 or high CCL3L CN was more significantly (P=0.0008) associated with protection from in utero infection than Hap-A1 (P=0.028) or high CCL3L CN (P=0.002) alone. Linkage disequilibrium between Hap-A1 and high CCL3L CN appears unlikely given that a Nigerian population showed an opposite relationship.


Assuntos
Quimiocina CCL3/genética , Dosagem de Genes , Infecções por HIV/genética , Infecções por HIV/transmissão , HIV-1 , Haplótipos , África Subsaariana/epidemiologia , Fármacos Anti-HIV/uso terapêutico , Antígenos CD4/sangue , Feminino , Predisposição Genética para Doença , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , Humanos , Lactente , Transmissão Vertical de Doenças Infecciosas , Desequilíbrio de Ligação , Nevirapina/uso terapêutico , Polimorfismo de Nucleotídeo Único , Carga Viral
16.
Artigo em Inglês | MEDLINE | ID: mdl-21146448

RESUMO

A homemade photoacoustic spectrometer has been constructed for monitoring gas emission from several sources. Numerous air pollutant gases are emitted exhaust of industries, vehicles and power plants. The photoacoustic technique is extremely sensitive and selective in detecting various gases. This work focuses on the gas emitted by the ceramic industry in northern Rio de Janeiro State in Brazil, the ceramic industry plays a remarkable role in the economy activity of this region, in recent years, this region developed into a significant red ceramic complex. The potential impact on the atmospheric environment of the region due to gaseous pollutant emissions from these anthropogenic sources needs to be evaluated. In this work we identified NH3 present in the samples collected in the kiln of a ceramic plant, in the concentration range of 33-52 ppmV. The ammonia gas present in our collected samples might come from the excess nitrogen in the manure soil from where the ceramic material was extracted. This soil was used for the sugarcane culture which is another important economic activity of this region.


Assuntos
Acústica , Amônia/análise , Dióxido de Carbono/química , Cerâmica/química , Resíduos Industriais/análise , Lasers , Luz , Absorção , Acústica/instrumentação , Calibragem , Etilenos/química , Limite de Detecção , Análise Espectral , Temperatura
17.
J Hazard Mater ; 110(1-3): 161-71, 2004 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-15177737

RESUMO

Oil spills represent a significant environmental issue in Brazil. This paper presents the latest results of a comprehensive experimental programme aimed at understanding how the presence of spilled oil affects the properties of sands and at studying alternatives to remediate the affected shores. Results indicate that oil causes a slight increase in grain size and uniformity, and oiled debris presents a smaller void ratio but a larger unit weight. It was also observed that effective strength parameters for both the natural and oiled debris were the same although the undrained strength of a natural sand is much higher than that of the contaminated sand. At ambient temperature, oiled debris emits methane and ammonia, and these emissions tend to increase with rising temperatures. On the other hand, the oil and grease content from oiled debris decreases with rising temperature and prolonged exposure. Finally, in situ thermal desorption seems to be a promising method for cleaning debris from oil spills. It is simple, fast and avoids all the difficulties associated with digging up the soil for disposal or cleanup.


Assuntos
Óleos Combustíveis/análise , Resíduos Perigosos/prevenção & controle , Dióxido de Silício/química , Poluição Química da Água/prevenção & controle , Brasil , Temperatura Alta , Modelos Químicos , Água do Mar
20.
Z Geburtshilfe Neonatol ; 205(6): 236-41, 2001.
Artigo em Alemão | MEDLINE | ID: mdl-11745010

RESUMO

PATIENT REPORTS: We report on a male preterm infant (gestational age 31 weeks, birth weight 1420 g) and a male term infant (gestational age 38 weeks, birth weight 3680 g) with ornithine transcarbamylase (OTC) deficiency. After inconspicuous cardiopulmonary adjustment, both entered a state of metabolic crisis with respiratory insufficiency and ventilatory requirement at the 2nd and 4th day of life, respectively. Diagnosis of hyperammonemia (NH(3) > 1000 micromol/l) was followed by the detection of a plasma amino acid pattern that is typical for OTC-deficiency and an excessive orotic aciduria. Beside intravenous treatment (insulin-glucose-infusion, lipid infusion, sodium benzoate, arginine, L-carnitine), the preterm infant received an exchange transfusion and was supplied with central venous catheters, hemofiltration and hemodialysis. He died after severe disturbances of circulation and coagulation at the 14th day. The male term infant tolerated the effective hemofiltration and was dicharged home with specific therapy at day 26. CONCLUSIONS: Time of diagnosis and influence of additional risk factors are decisively for the prognosis of OTC-deficiency. The immediate aims of therapy (stabilization of vital functions, reduction of plasma ammonium, control of nutrition) can only be realized in cooperation between neonatology, division of metabolism, pediatric nephrology and pediatric surgery.


Assuntos
Doenças do Prematuro/terapia , Doença da Deficiência de Ornitina Carbomoiltransferase/terapia , Equipe de Assistência ao Paciente , Transfusão Total , Evolução Fatal , Feminino , Hemofiltração , Humanos , Recém-Nascido , Doenças do Prematuro/diagnóstico , Terapia Intensiva Neonatal , Masculino , Doença da Deficiência de Ornitina Carbomoiltransferase/diagnóstico , Gravidez
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