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1.
Materials (Basel) ; 17(6)2024 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-38541430

RESUMO

This study examined the thermal dehydration characteristics of CaSO4∙2H2O in a constant-volume rotary vessel. The experiment used CaSO4∙2H2O particles obtained from the crushed waste gypsum board. The particle size ranged from 850 to 2000 µm, and the experiment was carried out at varying rotation speeds of 1, 10, and 35 rpm, with the vessel temperature heated to 180 °C. Temperature and pressure inside the vessel were measured simultaneously using the thermocouple and the pressure sensor. The XRPD measurement analyzed the transition of CaSO4∙2H2O after the heating of particles. The result showed that the temperature growth rate was similar for high rotation speeds of 10 and 35 rpm, while periodic temperature changes occurred at the low rotation speed of 1 rpm. A distinguishing flow pattern was observed at the low rotation speed, and the particles inside the vessel collapsed periodically downward. This particle behavior was related to the temperature distribution of the rotation speed of 1 rpm. Additionally, the pressure in the vessel increased rapidly at higher rotation speeds. This trend indicates the desorption of the crystal water of CaSO4∙2H2O due to the increasing temperature in the case of high rotation speed. Also, the XRPD measurement results showed the appearance of CaSO4∙0.5H2O under the higher rotation speed conditions, and the mass fraction of CaSO4∙0.5H2O increased with the rotation speed. Overall, the present study suggests that rotation speed plays a crucial role in determining the heat conduction and heat transfer of particles in a constant-volume rotary vessel.

2.
Materials (Basel) ; 15(6)2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35329644

RESUMO

This study focused on the vibrating fluidized-bed-type powder feeder used in HVAF thermal spraying equipment. This feeder has been used in thermal spraying equipment and industrial applications. However, particulate materials' flow mechanism and stable transport characteristics have not been fully understood. This study experimentally investigated the fluidization characteristics, powder dispersion state, and powder transportation characteristics of Al2O3 particles during vertical vibration fluidization. The material used was Al2O3 particles of 2.9 µm and 3808 kg/m3, classified as the group C particles in the Geldart diagram. As experimental conditions, the fluidized air velocity to the bottom of the powder bed and the vibration intensity in the vertical direction changed. The critical fluidization air velocity was defined to evaluate the generating powder flow by vertical vibrating fluidization. As a result, good fluidization of the powder bed of Al2O3 was obtained by the vertical vibration, as well as an airflow that was higher than the critical fluidization air velocity. Regarding powder transportation characteristics, it was clarified that the fluidized air velocity at the bottom of the powder dispersion vessel and the pressure difference from the powder dispersion vessel to the transportation part significantly affect the mass flow rate.

3.
Artif Organs ; 34(5): 377-83, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20633152

RESUMO

Using a nonlinear three-dimensional finite element analysis simulating loading conditions, we designed a new type of proximal-fitting, anterolaterally-flared, arc-deposit hydroxyapatite-coated anatomical femoral stem (FMS-anatomic stem; Japan Medical Materials, Osaka, Japan) for cementless total hip arthroplasty (THA) for Japanese patients with dysplastic hip osteoarthritis. The aim of the present study was to analyze the clinical and radiographic outcomes of the new stem. We reviewed 143 consecutive patients (164 hips; 13 men, 14 hips; 130 women, 150 hips; age at surgery, 56.6 +/- 7.6 years, mean +/- SD, range, 30-74) who underwent cementless THA using the FMS-anatomic stem at a single institution, with a follow-up period of 7.6 +/- 1.6 years (range, 5.3-11.0). Harris Hip score improved from 46.1 +/- 12.6 before surgery to 90.0 +/- 8.9 points post-THA. The 7.6-year survival rate of the stem was 99.0% after revision for aseptic loosening. Radiographs at follow-up confirmed the stability of the femoral stems within the femoral canal in all cases, with sufficient bone ingrowth. None of the patients had subsidence of the stem exceeding 2.0 mm within the femoral canal or changes in varus or valgus position of more than 2.0 degrees . The FMS-anatomic stem provided excellent results in patients with dysplastic hip osteoarthritis. Our analysis confirmed reduced radiolucency around the stem in Gruen zones, minimal subsidence, appropriate stress shielding, and promising medium-term stability within the femoral canal in our patients.


Assuntos
Artroplastia de Quadril/métodos , Fêmur/diagnóstico por imagem , Articulação do Quadril/diagnóstico por imagem , Prótese de Quadril , Osteoartrite do Quadril/cirurgia , Adulto , Idoso , Feminino , Fêmur/cirurgia , Seguimentos , Articulação do Quadril/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite do Quadril/diagnóstico por imagem , Radiografia
4.
J Nucl Med ; 50(11): 1808-14, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19837766

RESUMO

UNLABELLED: Osteoporosis represents a significant side effect of glucocorticoid therapy, and alendronate has been reported to prevent this glucocorticoid-induced osteoporosis. Functional imaging with (18)F-fluoride PET allows quantitative analysis of bone metabolism in specific skeletal regions. However, only a few studies have quantitatively determined bone turnover and metabolism in glucocorticoid-induced osteoporosis by radiologic imaging techniques including PET. The aim of this study was to examine changes in regional bone remodeling and turnover as measured by (18)F-fluoride PET, the relationship between these measured changes and conventional bone metabolism parameters, and the effect of alendronate treatment. METHODS: The study group consisted of 24 postmenopausal women (mean age, 59.7 y) who had various diseases, excluding rheumatoid arthritis, and had been treated with 10 mg or more of oral glucocorticoids (prednisolone equivalent) per day for more than 6 mo. Treatment with 5 mg of alendronate per day began at the time of study entry and continued for 12 mo. (18)F-fluoride PET was performed at baseline, 3 mo, and 12 mo to determine localized bone turnover, and the results were compared with other bone metabolism parameters. RESULTS: Lumbar spine standardized uptake values (SUVs) were significantly lower (P < 0.05) in the osteoporotic group (T-score < or = -2.5) than in the group that was healthy or osteopenic (T-score > -2.5). Patients treated with alendronate for 12 mo exhibited significant decreases in serum bone-specific alkaline phosphate (P < 0.05), urinary N-telopeptide for type I collagen (P < 0.01), lumbar spine SUV (P < 0.01), and femoral neck SUV (P < 0.01) in association with a gradual increase in bone mineral density (BMD) of the lumbar spine relative to the baseline value (P < 0.05). Although there was a significant correlation between BMD and SUV in the lumbar spine at baseline (P < 0.05), there was no correlation between the 2 variables at 12 mo of treatment with alendronate. CONCLUSION: Alendronate treatment resulted in significant decreases in bone metabolism and turnover in the lumbar spine. It also led to an increase in BMD of the lumbar spine in patients with glucocorticoid-induced osteoporosis. Our findings suggest that antiresorptive therapy has a direct bone-metabolism effect on skeletal kinetics in glucocorticoid-induced osteoporosis at the clinically important site of the lumbar spine.


Assuntos
Alendronato/farmacologia , Osso e Ossos/efeitos dos fármacos , Osso e Ossos/metabolismo , Fluoretos , Glucocorticoides/efeitos adversos , Osteoporose/induzido quimicamente , Osteoporose/diagnóstico por imagem , Idoso , Alendronato/uso terapêutico , Biomarcadores/metabolismo , Densidade Óssea/efeitos dos fármacos , Osso e Ossos/diagnóstico por imagem , Osso e Ossos/fisiopatologia , Feminino , Fluoretos/química , Fluoretos/metabolismo , Radioisótopos de Flúor/química , Humanos , Pessoa de Meia-Idade , Osteoporose/metabolismo , Osteoporose/fisiopatologia , Tomografia por Emissão de Pósitrons , Pós-Menopausa/metabolismo , Estudos Prospectivos
5.
Clin Rehabil ; 20(3): 239-45, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16634343

RESUMO

UNLABELLED: OBJECTIVE To evaluate the effects of a mathematical procedure that adjusts for gait velocity on the variability seen in gait analysis. DESIGN: Evaluation before and after compensation. SETTING: Gait laboratory, Fukui University Hospital, Japan. SUBJECTS: Fourteen normal volunteers. OUTCOME MEASURES: A computerized gait analysis system with two forceplates and a light source spot measuring device was used. Gait measurement in each subject was performed on three different days. RESULTS: The gait parameters measured on three different days were significantly different, particularly step length, stride length, velocity, the components of floor-reaction forces and hip motion. In these parameters, intraclass correlation coefficient, ICC (1,1) was not high (range 0.05-0.71). However, there was a high correlation between these parameters and velocity and high repeatability was obtained following compensation for velocity (ICC (1,1), range 0.73-0.97). In contrast, compensation of parameters whose measurement was not significantly different before compensation did not improve ICC (1,1). Variability of all parameters was acceptable, however CV (an index of variability) improved significantly after compensation compared with that before compensation in six of 15 parameters. CONCLUSIONS: Our findings suggest that low repeatability in gait parameters should be considered even when the gait of normal subjects is measured on different days. A high repeatability and more acceptable variability were obtained when the data were compensated for velocity.


Assuntos
Marcha/fisiologia , Modelos Biológicos , Análise de Variância , Humanos , Análise de Regressão , Reprodutibilidade dos Testes , Processamento de Sinais Assistido por Computador
6.
Arch Phys Med Rehabil ; 87(11): 1436-41, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17084116

RESUMO

OBJECTIVE: To determine the effects of lateral wedged insoles on knee kinetics and kinematics during walking, according to radiographic severity of medial compartment knee osteoarthritis (OA). DESIGN: A prospective case control study of patients with medial compartment OA of the knee. SETTING: Gait analysis laboratory in a university hospital. PARTICIPANTS: Forty-six medial compartment knees with OA of 23 patients with bilateral disease and 38 knees of 19 age-matched healthy subjects as controls. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: We measured the peak external adduction moment at the knee during the stance phase of gait and the first acceleration peak after heel strike at the lateral side of the femoral condyles. Kellgren and Lawrence grading system was used for radiographic assessment of OA severity. RESULTS: The mean value of peak external adduction moment of the knee was higher in OA knees than the control. Application of lateral wedged insoles significantly reduced the peak external adduction moment in Kellgren-Lawrence grades I and II knee OA patients. The first acceleration peak value after heel strike in these patients was relatively high compared with the control. Application of lateral wedged insoles significantly reduced the first acceleration peak in Kellgren-Lawrence grades I and II knee OA patients. CONCLUSIONS: The kinetic and kinematic effects of wearing of lateral wedged insoles were significant in Kellgren-Lawrence grades I and II knee OA. The results support the recommendation of use of lateral wedged insoles for patients with early and mild knee OA.


Assuntos
Aparelhos Ortopédicos , Osteoartrite do Joelho/reabilitação , Índice de Gravidade de Doença , Sapatos , Idoso , Fenômenos Biomecânicos , Estudos de Casos e Controles , Feminino , Marcha , Humanos , Masculino , Osteoartrite do Joelho/fisiopatologia , Estudos Prospectivos , Caminhada
7.
Arch Phys Med Rehabil ; 86(3): 527-33, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15759240

RESUMO

OBJECTIVE: To investigate changes in axonal flow after nerve root compression by using immunohistochemical techniques to detect calcitonin gene-related peptide (CGRP), which is thought to be involved in pain sensation. DESIGN: Experimental, controlled study. SETTING: University medical school in Japan. ANIMALS: Forty adult mongrel dogs (weight, 7-15kg). INTERVENTIONS: In dogs, the lumbar nerve roots were compressed using 4 types of clips with different pressures. Changes of CGRP levels in the spinal dorsal horn, dorsal root, and dorsal root ganglia (DRG) were examined immunohistochemically after compression for 24 hours or for 1 week. MAIN OUTCOME MEASURES: CGRP-positive neurons and CGRP-positive fibers. RESULTS: After compression, axonal flow in the dorsal root was impaired, accumulation of CGRP was observed distal to the site of compression, and the number of DRG cells showing positively for CGRP decreased. Compression for 1 week resulted in a decrease in the number of CGRP-positive fibers in the spinal dorsal horn. CONCLUSIONS: These findings indicate that CGRP dynamics are modified by nerve compression.


Assuntos
Peptídeo Relacionado com Gene de Calcitonina/fisiologia , Neurônios Aferentes/patologia , Radiculopatia/patologia , Animais , Cães , Gânglios Espinais/patologia
8.
Clin Orthop Relat Res ; (403): 161-7, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12360022

RESUMO

To investigate the effects of total knee arthroplasty on joint proprioception, the absolute angular error of the knee in 38 consecutive patients before and after total knee arthroplasty for osteoarthritis and in 23 age-matched control subjects were examined. Varus and valgus laxity of the knee and muscle strengths of the thigh were measured using appropriate instruments. There were no significant differences in absolute angular error before and after total knee arthroplasty, independent of retaining or substituting the posterior cruciate ligament. The absolute angular error of the knee with a normal appearing anterior cruciate ligament was larger than that with a missing anterior cruciate ligament before total knee arthroplasty and decreased significantly after surgery. The absolute angular error correlated with the varus and valgus laxity of the knee, but did not correlate with the strength of thigh muscles after total knee arthroplasty. These results suggest that deficiency of the anterior cruciate ligament may not adversely affect proprioception in severe knee osteoarthritis. In addition, proper ligament balance may partly contribute to better proprioception after total knee arthroplasty.


Assuntos
Artroplastia do Joelho/efeitos adversos , Instabilidade Articular/etiologia , Instabilidade Articular/fisiopatologia , Articulação do Joelho/fisiopatologia , Articulação do Joelho/cirurgia , Osteoartrite/fisiopatologia , Osteoartrite/cirurgia , Complicações Pós-Operatórias , Propriocepção/fisiologia , Idoso , Idoso de 80 Anos ou mais , Ligamento Cruzado Anterior/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/fisiopatologia , Amplitude de Movimento Articular/fisiologia
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