RESUMEN
BACKGROUND: The short-term corrosion and micromechanical behavior of 32 unique head-neck taper design/material/assembly conditions was tested using an incremental cyclic fretting corrosion (ICFC) test method previously developed. METHODS: Seven materials, design, and simulated surgical parameters were evaluated, each being assigned 2 conditions for testing, using a 27-2 (7 factor, quarter factorial) design of experiments test matrix. The factors explored were (1) seating load, (2) head-neck offset, (3) material combination, (4) taper diameter, (5) taper roughness, (6) angular mismatch/engagement, and (7) taper length. Each sample underwent assembly, ICFC testing, pull off. RESULTS: Low seating load and high head offset correlated with increased fretting corrosion (P < .05). High head offset also contributed to a lower onset load for fretting current and higher micromotion (P < .05). Head subsidence measured over the ICFC test for samples seated at 100 N was significantly higher than samples seated at 4000 N. Micromotion for 12-mm head offsets was statistically higher than samples with a 1.5-mm head offset. A number of interactive effects were observed. For example, samples seated at 4000 N were less sensitive to head offset than samples seated at 100 N in terms of the resulting fretting current. CONCLUSION: Taper locking position, material combination, taper engagement length, taper roughness, and taper dimensions all had weak or no correlation with fretting current and taper micromotion. This test method and experimental design is a versatile means of assessing potential new taper designs in the future.
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Artroplastia de Reemplazo de Cadera/efectos adversos , Artroplastia de Reemplazo de Cadera/instrumentación , Prótesis de Cadera/efectos adversos , Diseño de Prótesis , Falla de Prótesis , Corrosión , Técnicas In Vitro , Estrés MecánicoRESUMEN
El objetivo del presente trabajo fue proponer un modelo estructural que delinee la relación que guardan distintas caracterÃsticas psicológicas en su relación con problemas de salud mental por medio de un modelo de ecuaciones estructurales. En una muestra no aleatoria e intencional de N = 231 estudiantes, el modelo especificado demuestra que las variables de ira-rasgo, abnegación y locus de control interno tienen efectos en problemas de salud mental a través de mediadores como la ira contenida, la falta de asertividad y la autoeficacia, y que estos guardan las relaciones teóricas esperadas (X2 = 50.24, gl = 35 y p = 0.04; razón X2/gl = 1.44, CFI = .98, NFI = .93, IFI = .98, RMSEA = .04). Se discuten estos hallazgos en términos de su contribución a la comprensión de los mecanismos de la compleja relación de las caracterÃsticas psicológicas, la personalidad y la salud.
The objective of this study was to propose a structural model that delineates the relationship between different psychological characteristics in relation to mental health problems through a structural equation model. In a non-random, intentional sample of N = 231 students, the specified model demonstrates that anger-trait, self-denial and internal locus of control variables have effects on mental health problems through mediators such as anger-in, lack of assertiveness, and self-efficacy, and that they keep the expected theoretical relationships (X2 = 50.24, gl = 35 and p = 0.04; razón X2/gl = 1.44, CFI = .98, NFI = .93, IFI = .98, RMSEA = .04) These findings are discussed in terms of their contribution to understanding the mechanisms of the complex relationship among psychological characteristics, personality and health.
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Nineteen samples from the aerial parts in bloom of Acantholippia seriphioides (Verbenaceae) were collected in three provinces belonging to the Cuyo region of Argentina. The essential oils were obtained by hydrodistillation, yielding between 0.57 and 2.46 percent (v/w). On the basis of the 13 main compounds determined by GC-FID-MS, representing the 87.2 and 95.3 percent of the total identified, four chemotypes were determined: carvacrol, thymol, cis and trans-dihydrocarvone and linalool-geraniol. The co-occurrence of different chemotypes in a same population indicates that the sample collection must be carefully done with the aid of an in situ olfactory testing of the plants, since no morphological differences at first sight were observed among them. The results showed in this study suggest that the pattern of variations for this species exists throughout its natural distribution area...
Se colectaron 19 muestras de partes aéreas en floración de Acantholippia seriphioides (Verbenaceae) de tres provincias de la región de Cuyo de la Argentina. Los aceites esenciales fueron obtenidos por hidrodestilación, arrojando rendimientos entre 0.57 y 2.46 por ciento (v/p). A partir de la determinación por GC-FID-MS de los 13 compuestos principales, que representaban entre el 87.2 y 95.3 por ciento del total de los identificados, fueron determinados cuatro quimiotipos: carvacrol, timol, cis y trans-dihidrocarvona, y linalol-geraniol. La co-ocurrencia de diferentes quimiotipos en una misma población indica que la colecta debe ser realizada con la ayuda de un examen olfatorio in situ de la planta, ya que, a primera vista no se observan diferencias morfológicas entre ellas. Los resultados sugieren que el patrón de variación para esta especie existe en toda su área de distribución natural...
Asunto(s)
Humanos , Aceites Volátiles/química , Extractos Vegetales/química , Verbenaceae , Argentina , Biodiversidad , Cromatografía de Gases/métodos , Cromatografía de Gases y Espectrometría de MasasRESUMEN
In this study, we examined the protective effects of Caesalpinia sappan L. and its major component, brazilin, against tert-butylhydroperoxide (t-BHP)-induced cell death in House Ear Institute-Organ of Corti 1 (HEI-OC1) cells. We found that the extract of C. sappan L. and brazilin induced antioxidant response element (ARE)-luciferase activity and heme oxygenase-1 (HO-1) expression in a concentration-dependent manner. The inductive effect of brazilin was more potent than the extract of C. sappan L. and the expression of HO-1 reached a peak at 12 h after brazilin treatment. The extract and brazilin protected the cells against t-BHP-induced cell death. Their protective effects were abrogated by zinc protoporphyrin IX (ZnPP IX), a HO inhibitor. These results demonstrate that the extract of C. sappan L. and brazilin induce the expression of HO-1 and the enzyme diminishes t-BHP-induced cell death in HEI-OC1 cells.
Asunto(s)
Benzopiranos/farmacología , Caesalpinia/química , Hemo-Oxigenasa 1/metabolismo , Extractos Vegetales/farmacología , Animales , Antioxidantes/farmacología , Benzopiranos/química , Western Blotting , Muerte Celular/efectos de los fármacos , Línea Celular , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Hemo-Oxigenasa 1/antagonistas & inhibidores , Luciferasas/genética , Luciferasas/metabolismo , Ratones , Estructura Molecular , Órgano Espiral/citología , Órgano Espiral/efectos de los fármacos , Órgano Espiral/metabolismo , Estrés Oxidativo/efectos de los fármacos , Extractos Vegetales/química , Protoporfirinas/farmacología , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Elementos de Respuesta/genética , Transfección , terc-Butilhidroperóxido/farmacologíaRESUMEN
Se presenta un caso poco frecuente de leihmaniasis cutánea en un individuo adulto, japonés, residente en una zona periférica de Capiatá, a la altura del km 24 de la ruta 2. El paciente presentaba diversas lesiones en distintas zonas del cuerpo. En todas ellas se identificaron amastigotes de Leihmania a través de frotis, biopsias y cultivo. También las pruebas indirectas (intradermorreacción de Montenegro e inmunofluorescencia indirecta para leishmaniasis) resultaron positivas. El paciente respondió eficazmente al tratamiento con antimoniales. De acuerdo a las características clínicas y resultados laboratoriales, estimamos que el caso, poco común, corresponde a una leishmaniasis cutánea diseminada por metástasis. Se plantea una discusión acerca del origen geográfico de la infección