Fatigue Study of the Pre-Corroded 6082-T6 Aluminum Alloy in Saline Atmosphere

[Abstract] This work studies the influence of the saline atmospheric corrosion on the fatigue strength of 6061-T6 aluminum alloy. For this purpose, this alloy was subjected to tests in a salt spray corrosion chamber at different exposure times (1, 2, and 3 months) according to ASTM B117 standard. The morphological study of the pits was carried out by confocal microscopy. Subsequently, fatigue tests were performed at variable stresses whose maximum stress (Smax) was between 30% and 95% of the yield strength (S0) in order to keep them within the zone of elastic behavior of the material. Data were analyzed using the Basquin equation and the maximum likelihood function method. The results show a similar decrease in the conventional fatigue limit (2 × 106 cycles) after one month (98 MPa) and two months (91 MPa) of corrosion. After three months of corrosion, the material showed a very important reduction in the fatigue limit (68 MPa) with respect to the uncorroded material (131 MPa). The data of Se/S0 (fatigue limit/yield strength) versus the ratio Pm/Dm (pit average depth/pit diameter at zero depth) can be fitted to a logarithmic curve

Growth Hormone Receptor Signaling Pathways and its Negative Regulation by SOCS2

Growth hormone (GH) is a critical regulator of linear body growth during childhood but continues to have important metabolic actions throughout life. The GH receptor (GHR) is ubiquitously expressed, and deficiency of GHR signaling causes a dramatic impact on normal physiology during somatic development, adulthood, and aging. GHR belongs to a family of receptors without intrinsic kinase activity. However, GH binding to homodimers of GHR results in a conformational change in the receptors and the associated tyrosine kinase Janus kinase 2 (JAK2) molecules. Activated JAK2 phosphorylates the GHR cytoplasmic domain on tyrosine residues, and subsequent JAK2-dependent and JAK2-independent intracellular signal transduction pathways evoke cell responses including changes in gene transcription, proliferation, cytoskeletal reorganization, and lipid and glucose metabolism. JAK2 phosphorylates STAT5b, which is a key transcription factor in GH regulation of target genes associated with body growth, intermediate metabolism, and gender dimorphism; although STAT1, 3, and 5a have also been shown to be recruited by the GHR. In addition, many transcripts are regulated independently of STAT5b as a result of GHR activation of Src, ERK, and PI3K-mTOR signaling pathways. The analysis of molecular mechanisms involved in inactivation of GHR-dependent signaling pathway is also imperative for understanding GH physiology. This is clearly illustrated in the case of hepatic GHR-JAK2-STAT5b activation where signal duration regulates gender differences in liver gene expression. An early step in the termination of GH-dependent signaling is removal of GHRs by endocytosis and ubiquitination. The level of ubiquitin ligase SOCS2 is constitutively low, but its expression is rapidly induced by GH. SOCS2 binding to GHR complex promotes their ubiquitination and subsequent proteasomal degradation, contributing to the termination of the GH intracellular signaling. Clinically relevant, SOCS2 is a key negative regulator of GH-dependent body growth and lipid and glucose homeostasis. Furthermore, several cytokines, growth factors, xenobiotics, and sex hormones can regulate SOCS2 protein level, which provides a mechanism for cross-talking where multiple factors can regulate GHR signaling during somatic development. A better understanding of this complex regulation in physiological and pathological states will contribute to prevent health damage and improve clinical management of patients with growth and metabolic disorders

Xylan-binding xylanase Xyl30 from Streptomyces avermitilis: cloning, characterization, and overproduction in solid-state fermentation

A DNA fragment from the lignocellulolytic actinomycete Streptomyces avermitilis CECT 3339 was cloned using a DNA probe from the xylanase gene xysA of Streptomyces halstedii. The nucleotide sequence analysis revealed two potential ORFs, xyl30 and hd30, encoding a deduced multimodular F/10 xylanase with a binding domain and a secreted glycoxyl hydrolase, respectively. In Streptomyces lividans carrying the subcloned DNA fragment, two xylanase activity bands with estimated molecular masses of 42.8 and 35 kDa (named Xyl30 forms "h" and "l", respectively), were detected by zymograms and SDS-PAGE. The two xylanases had identical N-terminal sequences, suggesting that Xyl30 "l" derived from Xyl30 "h" by C-terminal processing in the culture supernatant. No transcripts of hd30 were detected by RT-PCR. Characterization of the partially purified Xyl30 "h" confirmed the presence of a modular endoxylanase containing a xylan-binding domain, which after processing in the culture supernatant loses the aforementioned domain and thus its capacity to bind xylan (Xyl30 "l"). Xyl30 "h" achieved maximal activity at pH 7.5 and 60 degrees C, retaining more than 50% of its activity from pH 3 to 9 and more than 40% after a 1-h incubation at 70 masculineC. Moreover, in the recombinant host strain up to 400 U xylanase/g medium (dry weight) was produced in solid-state fermentation (SSF) using cereal bran as substrate. The high production yields of this enzyme and its biochemical features make it a good candidate for use in industrial applications

Validation of a simple method for the interpretation of uterine cytology in cows

One of the main drawbacks of using endometrial cytology in cows is the time required for sample collection and interpretation. It is recommended to count a large number of polymorphonuclear neutrophils (PMN) and to calculate their overall percentage. However, since counting a large number of cells is a laborious method, it would be preferable to simplify the analysis by counting the number of PMN in few microscopic fields. Therefore, the aim of this study was to assess whether a simple test, based on calculating the average number of PMN in 10 fields at 1000×, could be a reliable technique for the diagnosis of endometritis. Two hundred and sixty endometrial samples were taken from Holstein cows at different postpartum stages using an adapted cytobrush. Smears obtained were air-dried for fixing and stained with a Romanowsky-type procedure. To evaluate the counting method, the percentage of PMN in 150 cells was calculated as well as the average number of PMN in 10 fields at 1000×. Receiver operating characteristic (ROC) curves was constructed to evaluate both methods, the percentage of PMN (used as reference) and the average number of PMN. It was observed that the area under the curve is (regardless of cut-off used) higher than 0.99 and the correspondence between both methods were 1.58 PMN/field for the cut-off value of 15% and 2.40 PMN/field for the cut-off value of 20%. These results show that this simple method could be used to determine the percentage of PMN in endometrial cytological samples and to diagnose endometritis in cowsSupported by the Xunta de Galicia (Galician Plan for Research and Technological Development; Grant No. PGIDIT07MRU002E) and the Friesian Federation of Galician, A Coruna, SpainS

Evaluación Funcional del Adulto Mayor: Consultorio Médico 262, Policlínico "Turcios Lima", Julio - Diciembre del 2006 / Functional assessment of the elderly: No-262 Doctor's Office, "Turcios Lima" Teaching Outpatient Clinic, July-December 2006

Se realizó una investigación de Desarrollo Tecnológico, descriptiva, transversal y prospectiva, con el objetivo de evaluar el estado funcional e integral de los adultos mayores pertenecientes al Consultorio Médico No. 262, Grupo Básico de trabajo No.5, Consejo Popular "Capitán San Luís", Policlínico Universitario "Turcios Lima", Municipio Pinar del Río en el período comprendido de julio-diciembre de 2006. El universo está constituido por los 110 ancianos de nuestro consultorio, correspondiéndose con la muestra. Para la recogida de la información se utilizó el análisis de la situación de salud del sector, las historias de salud familiar e individuales, también se aplicó un cuestionario siempre bajo la voluntariedad y aceptación de las personas a participar en nuestra investigación, basado en la Escala Geriátrica de Evaluación Funcional(EGEF), así como en el Índice de Actividades Básicas de la Vida Diaria (ABVD) de Katz y la Escala de Actividades Instrumentadas de la Vida Diaria de Lawton-Brody. Para su análisis estadístico se aplicó el Test de proporción de variables. Los resultados demostraron que el sexo femenino (63.64 %) y las edades de 60-64 años (22.73 %) fueron los que predominaron, constatándose un envejecimiento demográfico. El uso de medicamentos se detectó en el 70 % de los gerontes mientras la movilidad y el equilibrio estaban afectados en el 60.91 % y 56.36 %, respectivamente. La memoria fue el componente de la esfera psicológica más frecuentemente afectado (56.64 %). Las mujeres presentaron mayores dificultades que los hombres en la mayoría de las esferas, y existe en ellas también un predominio de las alteraciones del estado funcional e integral. Los ancianos independientes, activos y satisfechos con la vida que llevan, se presentaron de forma más relevante en el sexo masculino. Palabras clave: evaluación geriátrica, adulto mayor. ABSTRACT Technological Development, descriptive, cross-sectional and prospective research was conducted in order to assess the functional and general conditions of the elderly belonging to No-262 Doctor's Office, No-5 Basic Group of work "Capitan San Luis" Popular Council and "Turcios Lima" Teaching Outpatient Clinic, Pinar del Rio municipality during July-December 2006. The universe was comprised of 110 elderly attending to the Doctor's Office corresponding with the sample. To record the information an analysis of the health situation in the sector was performed, reviewing medical and familial histories, a questionnaire was applied always under voluntary nature, and the agreement of the persons to participate in the research based on the Scale of the Functional Geriatric Assessment (SFGA); as well as in the Katz's Rate of Basic Activities on Daily Life (RBADL), and the Scale of Lawton-Brody to the Instrumental Daily Activities was arranged. To the statistical analysis the Test of proportional variables was used. Results showed that female sex (63.64%) and ages 60-64 years old (22.73%) prevailed, verifying a demographic aging. The use of medications was detected in the 70% of the aged, while mobility and balance were influenced in 60.91% and 56.36%, respectively. Memory was the most affected component in the psychological sphere (56.64%). Women presented more difficulties than men in the majority of the spheres; prevailing in women disorders of the functional and general condition. The independent, active elderly, and those satisfied with their life belonged mainly to male sex. Key words: geriatric assessment, the elderly

Evaluación Funcional del Adulto Mayor: Consultorio Médico 262, Policlínico "Turcios Lima", Julio - Diciembre del 2006 / Functional assessment of the elderly: No-262 Doctor's Office, "Turcios Lima" Teaching Outpatient Clinic, July-December 2006

Se realizó una investigación de Desarrollo Tecnológico, descriptiva, transversal y prospectiva, con el objetivo de evaluar el estado funcional e integral de los adultos mayores pertenecientes al Consultorio Médico No. 262, Grupo Básico de trabajo No.5, Consejo Popular "Capitán San Luís", Policlínico Universitario "Turcios Lima", Municipio Pinar del Río en el período comprendido de julio-diciembre de 2006. El universo está constituido por los 110 ancianos de nuestro consultorio, correspondiéndose con la muestra. Para la recogida de la información se utilizó el análisis de la situación de salud del sector, las historias de salud familiar e individuales, también se aplicó un cuestionario siempre bajo la voluntariedad y aceptación de las personas a participar en nuestra investigación, basado en la Escala Geriátrica de Evaluación Funcional(EGEF), así como en el Índice de Actividades Básicas de la Vida Diaria (ABVD) de Katz y la Escala de Actividades Instrumentadas de la Vida Diaria de Lawton-Brody. Para su análisis estadístico se aplicó el Test de proporción de variables. Los resultados demostraron que el sexo femenino (63.64 %) y las edades de 60-64 años (22.73 %) fueron los que predominaron, constatándose un envejecimiento demográfico. El uso de medicamentos se detectó en el 70 % de los gerontes mientras la movilidad y el equilibrio estaban afectados en el 60.91 % y 56.36 %, respectivamente. La memoria fue el componente de la esfera psicológica más frecuentemente afectado (56.64 %). Las mujeres presentaron mayores dificultades que los hombres en la mayoría de las esferas, y existe en ellas también un predominio de las alteraciones del estado funcional e integral. Los ancianos independientes, activos y satisfechos con la vida que llevan, se presentaron de forma más relevante en el sexo masculino. Palabras clave: evaluación geriátrica, adulto mayor. ABSTRACT Technological Development, descriptive, cross-sectional and prospective research was conducted in order to assess the functional and general conditions of the elderly belonging to No-262 Doctor's Office, No-5 Basic Group of work "Capitan San Luis" Popular Council and "Turcios Lima" Teaching Outpatient Clinic, Pinar del Rio municipality during July-December 2006. The universe was comprised of 110 elderly attending to the Doctor's Office corresponding with the sample. To record the information an analysis of the health situation in the sector was performed, reviewing medical and familial histories, a questionnaire was applied always under voluntary nature, and the agreement of the persons to participate in the research based on the Scale of the Functional Geriatric Assessment (SFGA); as well as in the Katz's Rate of Basic Activities on Daily Life (RBADL), and the Scale of Lawton-Brody to the Instrumental Daily Activities was arranged. To the statistical analysis the Test of proportional variables was used. Results showed that female sex (63.64%) and ages 60-64 years old (22.73%) prevailed, verifying a demographic aging. The use of medications was detected in the 70% of the aged, while mobility and balance were influenced in 60.91% and 56.36%, respectively. Memory was the most affected component in the psychological sphere (56.64%). Women presented more difficulties than men in the majority of the spheres; prevailing in women disorders of the functional and general condition. The independent, active elderly, and those satisfied with their life belonged mainly to male sex. Key words: geriatric assessment, the elderly

Audiovestibular manifestations in patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease of unknown origin affecting up to 1% of the population. Little is known about audiovestibular impairment in patients with AS, especially the presence of cochleovestibular dysfunction in these patients. To investigate audiovestibular manifestations in AS, we studied a series of 50 consecutive patients who fulfilled the modified New York diagnostic criteria for AS and 44 matched controls. Individuals with history of cardiovascular disease, cerebrovascular complications, peripheral artery disease, renal insufficiency, syphilis, Meniere and other vestibular syndromes, infections involving the inner ear, barotrauma, or in treatment with ototoxic drugs were excluded. Most patients with AS were men (80%). The mean age at the time of study was 52.5 years, and mean age at the onset of symptoms was 34.4 years. Twenty-nine (58%) patients showed abnormal hearing loss in the audiogram compared to only 8 (18%) controls (p < 0.001). Values of audiometric tests (pure-tone average and speech reception threshold) yielded significant differences between patients and controls (p < 0.001). It is noteworthy that the audiogram shape disclosed a predominant pattern of high-frequency sensorineural hearing loss in AS patients (50%) compared to controls (18%) (p = 0.002). Also, AS patients exhibited abnormal vestibular tests more commonly than controls. AS patients had an increased frequency of head-shaking nystagmus (20%) compared to controls (0%) (p < 0.001). Moreover, patients (26%) showed a significantly increased frequency of abnormal caloric test compared to controls (0%) (p < 0.001). Finally, a significantly increased frequency of abnormal clinical test of sensory integration and balance with a predominant vestibular loss pattern was observed in patients (36%) compared to controls (5%) (p < 0.001). In conclusion, the current study demonstrates strong evidence for inner ear compromise in patients with AS

Characterization of Microstructural and Mechanical Properties of 17-4 PH Stainless Steel by Cold Rolled and Machining vs. DMLS Additive Manufacturing

The 17-4 PH stainless steel is widely used in the aerospace, petrochemical, chemical, food, and general metallurgical industries. The present study was conducted to analyze the mechanical properties of two types of 17-4 PH stainless steel—commercial cold-rolled and direct metal laser sintering (DMLS) manufactured. This study employed linear and nonlinear tensile FEM simulations, combined with various materials characterization techniques such as tensile testing and nanoindentation. Moreover, microstructural analysis was performed using metallographic techniques, optical microscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The results on the microstructure for 17-4 PH DMLS stainless steel reveal the layers of melting due to the laser process characterized by complex directional columnar structures parallel to the DMLS build direction. The mechanical properties obtained from the simple tension test decreased by 17% for the elastic modulus, 7.8% for the yield strength, and 7% for the ultimate strength for 17-4 PH DMLS compared with rolled 17-4 PH stainless steel. The FEM simulation using the experimental tension test data revealed that the 17-4 PH DMLS stainless steel experienced a decrease in the yield strength of ~8% and in the ultimate strength of ~11%. A reduction of the yield strength of the material was obtained as the grain size increased

Caracterización clínico-histopatológica del Carcinoma Basocelular

El Carcinoma Basocelular, (CBC), constituye el tumor epitelial maligno más frecuente de la piel; su etiología está muy asociada con la exposición a los rayos solares, por lo cual las personas de piel blanca y ojos claros son las más afectadas. Este tumor se caracteriza por su destrucción local, no así por su metástasis. Se describe una distribución similar en la zona bucomaxilofacial e incluso variantes intrabucales que, para muchos autores, no son más que Carcinomas ameloblásticos. El diagnóstico clínico, a veces, se hace difícil puesto que puede confundirse con otras entidades de la piel, por lo cual nos propusimos realizar un estudio transversal de las solicitudes e informes de biopsia, recibidos en el Departamento de Anatomía Patológica de la Facultad de Estomatología,en el período 1999-2004, con el diagnóstico de CBC clínica y/o histológicamente. Seleccionamos una muestra de 204 pacientes afectados;encontramos que la mayoría integraba el grupo entre los 71-80 años de edad;predominó el sexo masculino; la localización más frecuente fue en la nariz (47,4%), todo lo cual se comparó con lo reportado en la literatura actual. Predominó el tipo sólido dentro de las variantes histológicas y hubo una correlación de los diagnósticos clínicos con los histológicos de90,2%.Palabras Clave: Carcinoma Basocelular, epitelioma maligno, carcinoma basal facial,neoplasias en piel.</p