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1.
Inorg Chem ; 63(12): 5701-5708, 2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38471976

RESUMEN

Transparent and brown La2O3-MoO3 binary glasses were prepared in bulk form using a levitation technique. The glass-forming range was limited, with the primary composition being approximately 25 mol % La2O3. The 25La2O3-75MoO3 glass exhibited a clear crystallization at 546 °C, while determining its glass transition temperature was difficult. Notably, despite its amorphous nature, the glass possessed a density and packing density comparable to those of crystalline La2Mo3O12. X-ray absorption fine structure and Raman scattering analyses revealed that the glass structure closely resembles La2Mo3O12 due to the presence of isolated MoO42- units, whereas disordered atomic arrangement around La atoms was confirmed. The glass demonstrated transparency ranging from 378 to 5500 nm, and the refractive index at 1.0 µm was estimated to be 2.0. The optical bandgap energy was 3.46 eV, which was slightly smaller than that of La2Mo3O12. Additionally, the glass displayed a transparent region ranging from 6.5 to 8.0 µm. This occurrence results from the decreased diversity of MoOn units and connectivity of Mo-O-Mo, which resulted in the reduced overlap of multiphonon absorption. This glass formation, with its departure from conventional glass-forming rules, resulted in distinctive glasses with crystal-like atomic arrangements.

2.
Circ J ; 86(12): 1990-1997, 2022 11 25.
Artículo en Inglés | MEDLINE | ID: mdl-36047087

RESUMEN

BACKGROUND: Balloon atrial septostomy (BAS) is an essential catheterization procedure for congenital heart lesions. Recently, a balloon catheter for static BAS was approved for the first time in Japan as an alternative to the conventional pull-through BAS. Despite the expected increase in the use of static BAS, reports on its safety are scarce worldwide.Methods and Results: Data on static and pull-through BAS registered in a national registry between 2016 and 2018 were collected. During the study period, 247 sessions of static BAS and 588 sessions of pull-through BAS were performed on a total of 674 patients. Patients who underwent static BAS were older (P<0.001). The incidence of serious adverse events (4.3% vs. 0.9%, P=0.03) and the overall incidence of adverse events (8.1% vs. 3.2%, P=0.03) were higher in static BAS than in pull-through BAS. Among patients who underwent static BAS, the risk factor for adverse events was a body weight <3 kg at the time of the procedure (odds ratio: 4.3 [confidence interval: 1.7-11], P=0.003). CONCLUSIONS: This nationwide study revealed differences in patient background between static and pull-through BAS, as well as a higher incidence of adverse events related to static BAS. Patients weighing <3 kg are at high risk for adverse events after static BAS and may require surgical and circulatory support backup.


Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Transposición de los Grandes Vasos , Humanos , Procedimientos Quirúrgicos Cardíacos/métodos , Cateterismo/efectos adversos , Factores de Riesgo , Oportunidad Relativa , Sistema de Registros , Transposición de los Grandes Vasos/epidemiología , Transposición de los Grandes Vasos/etiología , Transposición de los Grandes Vasos/cirugía
3.
Circ J ; 85(9): 1517-1524, 2021 08 25.
Artículo en Inglés | MEDLINE | ID: mdl-33692248

RESUMEN

BACKGROUND: Stent implantation for vascular stenosis associated with congenital heart diseases is commonly performed as an off-label procedure in Japan because there is no officially approved stent for any congenital heart disease.Methods and Results:We analyzed data from the Japanese Society of Congenital Interventional Cardiology Registry collected from January 2016 to December 2018. Patients who underwent stent implantation were enrolled in the present analysis. During the study period, there were 470 procedures, 443 sessions, and 391 cases. Of 443 sessions, 427 (96.4%) succeeded procedurally. There were no differences in the procedural success rates among age groups. In all, 416 sessions (367 patients; 94%) resulted in survival to 30 days after catheter intervention. Of 392 admissions, 357 patients (91%) survived to discharge. Only 4 deaths were directly related to stent implantation. Some in-hospital complications were observed during 55 of 443 sessions. Both hospital deaths and serious complications were significantly more frequent in the group with various preoperative risk factors. CONCLUSIONS: Although not officially approved for congenital heart diseases in Japan, stent implantation in congenital heart diseases has been widely and routinely performed for many years with safety and efficacy. The aim of stenting was variable and broad because of many different applications and morphological variations. These data may facilitate approval of such an important device in Japan.


Asunto(s)
Cardiología , Cardiopatías Congénitas , Humanos , Japón , Sistema de Registros , Stents/efectos adversos
4.
Indian J Clin Biochem ; 30(3): 351-6, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26089624

RESUMEN

We measured serum soluble vascular endothelial growth factor receptor 1 (sVEGFR1) and receptor 2 (sVEGFR2) levels in healthy Japanese individuals in order to establish a reference value using a specific ELISA. Significant differences were observed in serum sVEGFR1 and sVEGFR2 levels between children and adults. To demonstrate the usefulness of the reference value for children, we measured serum sVEGFR1 and sVEGFR2 levels in children with diarrhea positive (D+) hemolytic uremic syndrome (HUS) as a preliminary study. Serum sVEGFR2 levels in children with HUS were markedly higher than those in healthy children from the onset of D + HUS. The reference value for healthy children in the present study will allow normal and pathological conditions to be discriminated from each other in future study.

5.
Biomed Mater Eng ; 35(3): 293-302, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38277279

RESUMEN

BACKGROUND: The ultra-high molecular weight polyethylene (UHMWPE) component of artificial joints is one of the most important factors affecting the clinical outcomes of joint arthroplasty. Although the possibility of in vivo UHMWPE degradation caused by absorbed lipids has been reported, a quantitative evaluation of this phenomenon has not yet been performed. OBJECTIVE: This study aimed to establish the lipid index (LI) as a quantitative indicator of the amount of absorbed lipids and the first step to quantify their effects on UHMWPE. METHODS: The LI was defined using the infrared spectrum obtained with a Fourier-transform infrared spectrophotometer and verified using the retrieved UHMWPE components. RESULTS: The LI was consistent with the amount of extract recovered in reflux extraction with hexane. In addition, the LI could replace lipid extraction for calculating the oxidation index (OI) because the value obtained by subtracting the LI from the OI showed good agreement with the OI obtained after lipid extraction. CONCLUSION: The LI represents the amount of lipids absorbed by UHMWPE and is useful for quantitatively evaluating the effects of lipids on UHMWPE. In addition, the LI enables OI measurements that are unaffected by absorbed lipids without requiring troublesome lipid-extraction procedures.


Asunto(s)
Lípidos , Polietilenos , Polietilenos/química , Lípidos/química , Lípidos/análisis , Humanos , Espectroscopía Infrarroja por Transformada de Fourier , Prótesis Articulares , Ensayo de Materiales
6.
Proc Inst Mech Eng H ; : 9544119241253322, 2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38831562

RESUMEN

The delamination of ultra-high molecular weight polyethylene (UHMWPE) in artificial joints is a major cause limiting the long-term clinical results of arthroplasty. However, the conventional test method using simple reciprocation to evaluate the delamination resistance of UHMWPE materials has insufficient detection sensitivity. To reproduce delamination, the unconformity contact must be maintained throughout the test so that the maximum stress is generated below the surface. Therefore, a test method that applies a U-shaped motion comprising two long-linear and one short linear sliding motion was developed. The sensitivity, robustness, and reproducibility of the U-shaped delamination test were investigated and compared with the traditional test method. The traditional test method could reproduce delamination only in materials that had degraded considerably, whereas the U-shaped delamination test could reproduce delamination in a wide range of materials, demonstrating its superior sensitivity. Additionally, using a higher load helped accelerate the test without affecting the test results. The optimal length of the short linear sliding motion was confirmed to be 1 mm. Finally, the inter-laboratory reproducibility of the U-shaped delamination test was confirmed using the round-robin test. The U-shaped delamination test demonstrates high sensitivity, robustness, and reproducibility and contributes to the selection and development of UHMWPE materials and artificial joints with a lower risk of delamination.

7.
J Artif Organs ; 15(1): 49-56, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21956206

RESUMEN

The purpose of this study was to examine the hemodynamic characteristics of expanded polytetrafluoroethylene (ePTFE) pulmonary valves with bulging sinuses quantitatively in a pediatric pulmonary mechanical circulatory system designed by us, in order to propose the optimal design for clinical applications. In this study, we developed a pediatric pulmonary mock circulation system, which consisted of a pneumatic right ventricular model, a pulmonary heart valve chamber, and a pulmonary elastic compliance tubing with resistive units. The hemodynamic characteristics of four different types of ePTFE valves and a monoleaflet mechanical heart valve were examined. Relationships between the leaflet movements and fluid characteristics were evaluated based on engineering analyses using echocardiography and a high-speed video camera under the pediatric circulatory conditions of the mock system. We successfully performed hemodynamic simulations in our pediatric pulmonary circulatory system that could be useful for quantitatively evaluating the pediatric heart valves. In the simulation study, the ePTFE valve with bulging sinuses exhibited a large eddy in the vicinity of the leaflets, whereas the straight tubing exhibited turbulent flow. The Reynolds number obtained in the valve with bulging sinuses was calculated to be 1667, which was smaller than that in the straight tubing (R (e) = 2454).The hemodynamic characteristics of ePTFE pediatric pulmonary heart valves were examined in our mock circulatory system. The presence of the bulging sinuses in the pulmonary heart valve decreased the hydrodynamic energy loss and increased the systolic opening area. Based on an in vitro experiment, we were able to propose an optimal selection of pulmonary valve design parameters that could yield a more sophisticated pediatric ePTFE valve shape.


Asunto(s)
Prótesis Valvulares Cardíacas , Corazón/fisiología , Hemodinámica/fisiología , Modelos Cardiovasculares , Niño , Humanos , Ensayo de Materiales , Politetrafluoroetileno , Flujo Pulsátil/fisiología
8.
Immunopharmacol Immunotoxicol ; 34(5): 803-9, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22316079

RESUMEN

Propolis is a resinous substance collected by honeybees from leaf buds and cracks in the bark of various plants. It has been reported to show immunomodulatory activity. Previously, we reported the protective effect of Brazilian propolis ethanolic extract against the pathogenesis of collagen-induced arthritis (CIA), an experimental animal model of rheumatoid arthritis (RA). Moreover, we found that the protective effect against CIA was involved in suppression of the production of interleukin-17 (IL-17) in CIA mice. In the present study, we demonstrated for the first time that propolis inhibited IL-6 plus transforming growth factor-ß induced Th17 differentiation in vitro. Propolis also suppressed the IL-6-induced phosphorylation of signal transducer and activator of transcription 3 (STAT3), a cytokine-activated essential transcription factor in Th17 development, concomitantly with the enhanced suppressor of cytokine signaling 3 expression involved in the downregulation of STAT3 phosphorylation. These data suggest that the suppressive effect of propolis on Th17 differentiation might be useful for controlling unbalanced cytokine networks in autoimmune diseases.


Asunto(s)
Artritis Experimental/inmunología , Artritis Reumatoide/inmunología , Interleucina-6/inmunología , Própolis/farmacología , Factor de Transcripción STAT3/inmunología , Células Th17/inmunología , Animales , Artritis Experimental/inducido químicamente , Artritis Experimental/tratamiento farmacológico , Artritis Experimental/patología , Artritis Reumatoide/inducido químicamente , Artritis Reumatoide/tratamiento farmacológico , Artritis Reumatoide/patología , Abejas , Brasil , Masculino , Ratones , Ratones Endogámicos BALB C , Fosforilación/efectos de los fármacos , Fosforilación/inmunología , Células Th17/patología
9.
Inflammopharmacology ; 20(1): 19-26, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21861090

RESUMEN

Propolis is a resinous substance collected by honeybees from leaf buds and cracks in the bark of various plants. Propolis has been reported to have immunomodulatory activity. We hypothesized that propolis would be able to reduce the disease severity of rheumatoid arthritis. We evaluated the effect of Brazilian propolis ethanolic extract on the pathogenesis of collagen-induced arthritis (CIA) in mice. Mice fed propolis exhibited significant lower clinical arthritis scores than those fed the control diet. To investigate the mechanism of the effect of propolis on CIA mice, we examined interleukin-17 (IL-17) production in CIA mice fed propolis using an enzyme-linked immunospot assay and flow cytometric analysis. The numbers of IL-17-producing cells in the CIA mice fed propolis were significantly decreased. To determine direct influence of propolis on cytokine production, splenocytes were stimulated with phorbol myristate acetate in the presence of propolis extract in vitro. Concentration-dependent declines in IL-17 expression were observed by ELISA and real-time PCR methods. We further found that propolis significantly inhibited the differentiation of Th17 cells from murine splenocytes in a concentration-dependent manner. Taken together, our results may provide a new light on the potential mechanism of the immunosuppressive and anti-inflammatory effects of propolis.


Asunto(s)
Artritis Experimental/tratamiento farmacológico , Artritis Experimental/inmunología , Interleucina-17/antagonistas & inhibidores , Interleucina-17/biosíntesis , Própolis/farmacología , Animales , Antiinflamatorios/farmacología , Artritis Experimental/genética , Artritis Experimental/metabolismo , Brasil , Diferenciación Celular/efectos de los fármacos , Femenino , Inmunosupresores/farmacología , Interleucina-17/genética , Interleucina-17/inmunología , Ratones , Ratones Endogámicos DBA , ARN Mensajero/genética , ARN Mensajero/metabolismo , Bazo/inmunología , Bazo/metabolismo , Células Th17/efectos de los fármacos , Células Th17/inmunología , Células Th17/metabolismo
10.
Indian J Clin Biochem ; 27(4): 400-4, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24082468

RESUMEN

Most cytokine receptors including interleukin (IL)-9 have soluble counterparts in body fluids. We planned to investigate the pathophysiological significance of the serum soluble IL-9 receptor (sIL-9R) level. We determined the serum sIL-9Rα chain (sIL-9Rα) levels in 96 healthy Japanese individuals to establish a control value by means of specific human sIL-9Rα ELISA, followed by a preliminary application in a patient with diarrhea positive hemolytic uremic syndrome. Age was negatively correlated with the sIL-9Rα level (Spearman r = -0.241, n = 96, p = 0.0180). The serum sIL-9Rα level showed a progressive decline to the normal adult level by the age of 30. The serum sIL-9Rα level of the patient with HUS was markedly higher than those of the age-matched control from the onset of the disease. Because of the remarkable age-dependent variability of sIL-9Rα in healthy subjects, disease-related changes, as well as therapy-dependent alterations, should be considered with caution. Thus, it is recommended that when the serum sIL-9Rα levels of patients are evaluated, the values should be compared with those of age-matched controls. The established control value will be used to discriminate between normal and the pathological conditions in our future studies.

11.
Proc Inst Mech Eng H ; 236(2): 279-285, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34431397

RESUMEN

Poly-ether-ether-ketone (PEEK) and carbon fiber reinforced PEEK as orthopedic implant materials exhibit excellent material properties. Although delamination of PEEK materials has been reported in knee joint wear research, the delamination resistance behavior remains unclear. In this study, the delamination resistance of PEEK materials was investigated; these materials were compared to ultra-high molecular weight polyethylene (UHMWPE). The results of a ball-on-flat type delamination test indicated that the PEEK materials underwent delamination considerably earlier than UHMWPE, and the contact area of the PEEK materials was smaller than that of UHMWPE. Moreover, the indentation modulus, hardness, and coefficient of friction were higher for PEEK materials than for UHMWPE. The reduced tendency of PEEK materials to undergo deformation to mitigate stress concentration at low conformity contact conditions contributed to their inferior delamination resistance compared to that of UHMWPE. The delamination resistance of the PEEK materials was equivalent to that of degraded UHMWPE, which highlights the risk of delamination of PEEK implants in a clinical context. Consequently, when using PEEK materials as an implant component loaded at a low conformity contact condition, the material selection and component design must be carefully considered. Overall, the results of this study can help guide the future development of PEEK-based implants.


Asunto(s)
Éter , Cetonas , Materiales Biocompatibles , Fibra de Carbono , Ensayo de Materiales , Polietilenglicoles
12.
Chemosphere ; 289: 133181, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34875295

RESUMEN

To better understand the migration behavior of actinides in deep groundwater (GW), the interactions between doped tracers and deep GW components were investigated. La, Sm, Ho, and U tracers (10 or 100 ppb) were doped into sedimentary rock GW samples collected from 250 to 350 m deep boreholes in the experimental gallery of the Horonobe Underground Research Laboratory (URL), Hokkaido, Japan. To evaluate the effect of GW composition on the chemical speciation of actinides, the same tracers were doped into crystalline rock GW samples collected from 300 to 500 m deep boreholes in the experimental gallery at the Mizunami URL, Gifu Prefecture, Japan. Each GW sample was sequentially filtered through a micro-pore filter (0.2 µm) and ultrafilters with a 10 kDa nominal molecular weight limit. Next, the filtrate solutions were analyzed using inductively coupled plasma-mass spectrometry to determine the concentration of tracers retained in solution during each filtration step, and the used filters were analyzed using time-of-flight secondary ion mass spectrometry element mapping and X-ray absorption fine structure spectroscopy to determine the chemical species of the tracers trapped on each filter. It was determined that lanthanide migration was controlled by the amount of phosphates in the Horonobe GW. Therefore, it was expected that the solubility of minor actinides (MAs), which exhibit a similar chemical behavior to that of lanthanides, would be controlled by the formation of phosphates in sedimentary rock GW. Moreover, the data on the Mizunami GW indicated that a fraction of lanthanides and MAs formed hydroxides and/or hydroxocarbonates.


Asunto(s)
Elementos de Series Actinoides , Agua Subterránea , Elementos de la Serie de los Lantanoides , Filtración , Análisis Espectral
13.
J Neuroendovasc Ther ; 16(4): 192-197, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-37502454

RESUMEN

Objective: As an important evaluation index of vascular damage, the study aims to clarify the value of contact pressure applied to blood vessels and how it changes with respect to balloon pressure during balloon dilation. Methods: The contact pressure was evaluated through an in vitro measurement system using a model tube with almost the same elastic modulus as the blood vessel wall and our film-type pressure sensor. A poly (vinyl alcohol) hydrogel tube with almost the same elastic modulus was fabricated as the model vessel. The film-type sensor was inserted between the balloon catheter and the model vessel, and the balloon was dilated. Results: The contact pressure applied to the blood vessel was less than 10% of the balloon pressure, and the increase in contact pressure was less than 1% of the increase in balloon pressure (8 to 14 atm). Moreover, the contact pressure and its increase were larger in the model with a high elastic modulus. Conclusion: The contact pressure to expand the soft vessel model was not high, and the balloon pressure almost appeared to act on the expansion of the balloon itself. Our experiment using variable stiffness vessel models containing film-type sensors showed that the contact pressure acting on the vessel wall tended to increase as the wall became harder, even when the nominal diameter of the balloon was almost identical to the vessel. Our results can be clinically interpreted: when a vessel is stiff, the high-pressure inflation may rupture it even if its nominal diameter is identical to the diameter of the vessel.

14.
J Artif Organs ; 14(4): 348-56, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21698514

RESUMEN

Treatment of large (diameter 12-25 mm) or giant (diameter >25 mm) cerebral aneurysms with a broad neck in the cranio-cervical area is difficult and carries relatively high risks, even with surgical and/or endovascular methods. To this end, we have been developing a high-performance, self-expanding stent graft which consists of a commercially available NiTi stent (diameter 5 mm, length 20 mm) initially covered with a thin microporous segmented polyurethane membrane fabricated by the dip-coating method. Micropores are then created by the excimer laser ablation technique, and the outer surface is coated with argatroban. There are 2 types of micropore patterns: circular-shaped pore type (pore: diameter 100 µm, opening ratio 12.6%) and the bale-shaped pore type (pore: size 100 × 268 µm, opening ratio 23.6%). This self-expanding stent graft was tested on side-wall aneurysms of both canine carotid arteries that were experimentally induced using the venous pouches from the external jugular veins, with the self-expanding stent graft on one side and a bare self-expanding stent on the other side. All carotid arteries were patent and free of marked stenosis after 1 month. All aneurysms were occluded by stent grafts, while patent in those treated with bare stents. Histologically, the stent grafts with bale-shaped micropores and a high opening ratio were associated with less intimal hyperplasia (187 ± 98 µm) than the bare stents (341 ± 146 µm) or the stent grafts with circular micropores and a low opening ratio (441 ± 129 µm). A pore ratio of 23.6% was found to control intimal growth.


Asunto(s)
Aneurisma Intracraneal/terapia , Stents , Animales , Perros , Femenino , Hiperplasia/prevención & control , Aneurisma Intracraneal/patología , Neointima/patología
15.
J Immunoassay Immunochem ; 32(2): 145-55, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21391051

RESUMEN

We determined the urinary soluble tumor necrosis factor-α receptor type I (sTNFRI) and type II (sTNFRII) levels in healthy Japanese individuals to establish a reference value by means of specific ELISA. It was found that there were no significant differences between the urine sTNFRI and sTNFRII levels of children and adults. To demonstrate the usefulness of the reference value for children, we measured the urine sTNFRI and sTNFRII levels of children with diarrhea positive (D+) hemolytic uremic syndrome (HUS) as a preliminary study. The urine sTNFRI and sTNFRII levels of the patients with HUS were markedly higher than those of healthy children from the onset of D + HUS. Our reliable reference value for healthy children will allow us to discriminate between normal and pathological conditions in future studies.


Asunto(s)
Receptores Tipo II del Factor de Necrosis Tumoral/orina , Receptores Tipo I de Factores de Necrosis Tumoral/orina , Adulto , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Japón , Masculino , Persona de Mediana Edad , Solubilidad
16.
Nihon Kokyuki Gakkai Zasshi ; 49(5): 360-4, 2011 May.
Artículo en Japonés | MEDLINE | ID: mdl-21688644

RESUMEN

A 33-year-old woman used waterproofing spray and subsequently developed cough, sputum and chest pain about 8 hours later accompanied by dyspnea, fever and general fatigue. She was admitted to our hospital 4 days after the symptoms appeared. A chest CT scan on the first visit revealed diffuse mild centrilobular nodular opacities and ground-glass opacities in both lung fields. Hemosiderin-laden macrophages accounted for 11% of the histiocytes found in her bronchoalveolar lavage fluid, which also contained blood. Based on these findings, the patient was given a diagnosis of diffuse alveolar hemorrhage. This is the first report in Japan of diffuse alveolar hemorrhage occurring after the use of a waterproofing spray.


Asunto(s)
Aerosoles/efectos adversos , Hemorragia/inducido químicamente , Enfermedades Pulmonares/inducido químicamente , Adulto , Femenino , Compuestos de Flúor/efectos adversos , Humanos
17.
J Neurointerv Surg ; 13(2): 164-170, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33097626

RESUMEN

INTRODUCTION: Despite a decade of research into virtual stent deployment and the post-stenting aneurysmal hemodynamics, the hemodynamic factors which correlate with successful treatment remain inconclusive. We aimed to examine the differences in various post-treatment hemodynamic parameters between successfully and unsuccessfully treated cases, and to quantify the additional flow diversion achievable through stent compaction or insertion of a second stent. METHODS: A systematic review and meta-analysis were performed on eligible studies published from 2000 to 2019. We first classified cases according to treatment success (aneurysm occlusion) and then calculated the pooled standardized mean differences (SMD) of each available parameter to examine their association with clinical outcomes. Any additional flow diversion arising from the two common strategies for improving the stent wire density was quantified by pooling the results of such studies. RESULTS: We found that differences in the aneurysmal inflow rate (SMD -6.05, 95% CI -10.87 to -1.23, p=0.01) and energy loss (SMD -5.28, 95% CI -7.09 to -3.46, p<0.001) between the successfully and unsuccessfully treated groups were indicative of statistical significance, in contrast to wall shear stress (p=0.37), intra-aneurysmal average velocity (p=0.09), vortex core-line length (p=0.46), and shear rate (p=0.09). Compacting a single stent could achieve additional flow diversion comparable to that by dual-stent implantation. CONCLUSIONS: Inflow rate and energy loss have shown promise as identifiers to discriminate between successful and unsuccessful treatment, pending future research into their diagnostic performance to establish optimal cut-off values.


Asunto(s)
Velocidad del Flujo Sanguíneo/fisiología , Simulación por Computador , Hemodinámica/fisiología , Aneurisma Intracraneal/terapia , Stents Metálicos Autoexpandibles/tendencias , Humanos , Aneurisma Intracraneal/diagnóstico por imagen , Aneurisma Intracraneal/fisiopatología , Estrés Mecánico , Resultado del Tratamiento
18.
J Phys Chem A ; 114(13): 4664-71, 2010 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-20225902

RESUMEN

The local structure around the La(3+) ions in molten LaCl(3) and its mixtures with alkali and alkaline earth chlorides has been investigated by using extended X-ray absorption fine structure (XAFS) and molecular dynamics (MD) techniques. Such mixtures, which are of current technological interest, are known to be thermodynamically nonideal, and there has been a good deal of work to understand the structural effects factors that contribute to the nonideality. New experimental methods allow observations at the La K-absorption edge at the high temperatures of interest, and the ability of the technique to obtain reliable information even at very low La(3+) concentrations in multicomponent mixtures is demonstrated. Both the mean La(3+)-Cl(-) interionic separation and the mean La(3+) coordination number are found to decrease as the concentration of La(3+) in the mixture decreases. The rate of decrease depends on the identity of the alkali and alkaline earth cations present in the mixtures in a way that parallels the degree of nonideality of the different systems; it is greatest for those alkali cations that coordinate Cl(-) weakly. In dilute mixtures with such cations La(3+) is able to adopt a very stable octahedral coordination geometry but this is inhibited by the presence of more strongly coordinating cations like Li(+) and Mg(2+).

19.
J Biomed Mater Res B Appl Biomater ; 108(8): 3155-3161, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32491260

RESUMEN

Ultra-high molecular weight polyethylene (UHMWPE) is used as a bearing surface of joint prostheses and has been reported to absorb lipids such as squalene (SQ) and cholesterol esters in vivo. These lipids have been suggested by in vitro studies using SQ as a model lipid to have the potential to induce polymer degradation. However, the impact of lipid-induced degradation on the strength and wear resistance of UHMWPE is unknown. In this study, lipid-induced degradation was simulated by SQ absorption and subsequent accelerated aging, and its influence on the strength and wear resistance of UHMWPE was investigated using wear, fatigue crack growth, and delamination testing. Lipid-induced degradation was found to have little impact on fatigue crack growth rates and delamination resistance. These results were consistent with previous reports that lipid-induced degradation is localized near the surface. However, we also found that lipid-induced degradation increased the wear rate of both non-crosslinked and crosslinked UHMWPE by a factor of 2.5 and 14, respectively. These results indicate that lipid-induced degradation may affect the durability and long-term clinical outcome of joint replacements due to increased wear of UHMWPE.


Asunto(s)
Materiales Biocompatibles , Prótesis Articulares , Lípidos/química , Polietilenos/química , Artroplastia de Reemplazo , Reactivos de Enlaces Cruzados , Ensayo de Materiales , Escualeno/química
20.
Biomed Mater Eng ; 31(2): 119-129, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32568171

RESUMEN

BACKGROUND: Fourier-transform infrared spectroscopy (FTIR) is one of the standard methods to analyze ultra-high molecular weight polyethylene (UHMWPE) in orthopedic implants. For retrieved components, lipid extraction using an organic solvent prior to the measurement is necessary to eliminate the influence of lipids absorbed in vivo. However, its influence on the measurement has not been substantially investigated. OBJECTIVE: To investigate the influence of lipid extraction on the FTIR analysis of UHMWPE and to develop a novel method to obtain reliable results without inconvenient lipid extraction. METHODS: FTIR analysis was repeatedly performed on UHMWPE specimens from retrieved components before and after lipid extraction under various conditions. A method to calculate the extent of influence of the absorbed lipids from the FTIR spectra was developed using a peak separation technique. RESULTS: An elevated temperature was necessary for lipid extraction; however, it had the potential to influence the results if the conditions were not properly controlled. The results obtained using the peak separation technique coincided with those obtained after lipid extraction. CONCLUSION: The use of the peak separation technique enables the efficient acquisition of reliable results without the need for lipid extraction.


Asunto(s)
Análisis de Falla de Equipo/métodos , Lípidos/farmacocinética , Polietilenos/química , Polietilenos/farmacocinética , Absorción Fisicoquímica , Adulto , Tobillo , Artroplastia de Reemplazo de Tobillo/instrumentación , Artroplastia de Reemplazo de Cadera/instrumentación , Fraccionamiento Químico , Remoción de Dispositivos , Femenino , Prótesis de Cadera , Humanos , Lípidos/aislamiento & purificación , Lípidos/farmacología , Ensayo de Materiales , Oxidación-Reducción , Reoperación , Espectroscopía Infrarroja por Transformada de Fourier , Propiedades de Superficie/efectos de los fármacos
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