bluuebunny/crossref_metadata_2025 huggingface dataset:
Estudio de la intercara de una preforma híbrida infiltrada sin presión
Authors: Merchán M. , García de Cortázar M. , Egizabal P. , Peñalba F. , López A. J. , Torres B. , Rodrigo P. , Rams J.
Published: May 2011

En este trabajo se presenta la caracterización de la intercara matriz/refuerzo en un compuesto de matriz de aluminio reforzado con fibras de Saffil y partículas de alúmina, fabricado mediante el proceso de infiltración sin presión, Primex™. La caracterización microestructural y química del material compuesto se ha realizado mediante microscopía electrónica de barrido y mediante análisis semicuantitativo por energía dispersiva de rayos-X. Asimismo, se ha realizado una caracterización mecánica del material compuesto utilizando la técnica de nanoindentación. De la investigación se concluye que se tiene una buena unión entre los refuerzos y la matriz.
Estudio tribológico de aceros austeníticos tipo Hadfield: influencia del manganeso en su respuesta frente al desgaste
Authors: García A. , Varela Á. , Mier J. L. , Camba C. , Barbadillo F.
Published: May 2011

En este estudio se analiza la respuesta frente al desgaste de aceros austeníticos tipo Hadfield, en función del contenido de manganeso, partiendo de aceros con proporciones dentro del intervalo del 4 al 6 % de manganeso. El análisis tribológico se ha realizado mediante ensayos pin on disk, según norma ASTM G99-05, y los resultados obtenidos se han relacionado con la dureza y con la microestructura de cada muestra determinándose que, para este tipo de aceros, la resistencia al desgaste no sólo depende de la dureza del material sino que se ve muy influida por el tipo y distribución de precipitados existentes.
Comportamiento al desgaste de fundiciones tipo “silal”
Authors: Camba C. , Varela Á. , Blázquez V. , García A. , Mier J. L. , Barbadillo F.
Published: May 2011

Es este trabajo se han estudiado las propiedades tribológicas y mecánicas de cinco fundiciones con distintos contenidos de carbono y silicio. Cada fundición ha sido sometida a ensayos de dureza Brinell, y ensayos de resistencia al desgaste, según la norma ASTMG99, “Standard test method for wear testing with a pin-on-disk apparatus”. Se han correlacionado los resultados obtenidos para estos ensayos con la microestructura, la composición y el proceso de colada de cada una de las fundiciones.
Aplicación del modelo de daño de Gurson-Tvergaard-Needleman (GTN) para la simulación del ensayo miniatura de punzonado sobre probetas prefisuradas
Authors: Cuesta I. I. , Alegre J. M. , Barbáchano H.
Published: May 2011

El ensayo miniatura de punzonado (SPT) constituye una alternativa factible para la determinación de las propiedades mecánicas, en aquellos casos en los que no se dispone de material suficiente para la realización de ensayos convencionales. Actualmente, existe un gran interés en la utilización de este tipo de ensayo, sobre probetas prefisuradas (P-SPT), para la determinación de las propiedades a fractura del material. En el caso de que el comportamiento del material sea dúctil, el modelo de daño de Gurson-Tvergaard-Needleman (GTN) permite, en base a una serie de parámetros constitutivos, reproducir el comportamiento del material hasta su rotura. Los parámetros constitutivos tienen en cuenta la nucleación, crecimiento y coalescencia de microhuecos, como mecanismos de evolución del daño en materiales dúctiles. El objetivo del presente trabajo es el desarrollo de una metodología para la identificación de dichos parámetros constitutivos, a partir del ajuste numérico de los resultados experimentales obtenidos con los ensayos P-SPT.
Optimización de las propiedades mecánicas de las aleaciones AlSi7Mg moldeadas en arena
Authors: Loizaga A. , De la Fuente E. , Niklas A. , Barrenengoa J. , Fernández-Calvo A. I.
Published: May 2011

Se han estudiado las características mecánicas de la aleación AlSi7Mg, con objeto de elegir la composición y el tratamiento térmico idóneos para el moldeo de piezas en arena. Las propiedades mecánicas han sido evaluadas variando el contenido de magnesio, cubriendo tanto la aleación A356 como la A357. La incidencia del tratamiento térmico se ha estudiado en la aleación A356 variando la temperatura y el tiempo de precipitación, manteniendo constante el tratamiento de disolución. Se han definido distintos índices de calidad que combinan resistencia mecánica, límite elástico y alargamiento, permitiendo seleccionar un tratamiento térmico y una composición química adecuada para cada aplicación.
Diseño de molde para el establecimiento de la relación entre resultados de análisis térmico y microestructura del aluminio A357 en moldeo por microfusión
Authors: Bilbao Y. , Espinosa M. , Artola G. , Fernández-Calvo A. I. , Rodríguez P. P.
Published: May 2011

El tratamiento del metal fundido resulta esencial para mejorar las propiedades mecánicas de las aleaciones de aluminio. Los métodos de análisis térmico empleados habitualmente como medio de control están basados en el enfriamiento del metal en una copa metálica o en arena. En el caso de la microfusión, el enfriamiento se produce en un molde refractario a alta temperatura (entre 400 y 700°C), en el que las piezas además poseen espesores muy finos, de modo que los resultados de análisis térmico no son del todo fieles a lo que se obtiene en pieza. Como resultado del presente trabajo se obtiene un diseño de molde capaz de ajustarse a la tipología de pieza común en el moldeo a la cera perdida, lo que permitirá establecer, en ensayos futuros, la relación entre los resultados de análisis térmico, la microestructura en pieza y las propiedades mecánicas finales.
La tensión umbral para la fluencia, en un material de base magnesio procesado por pulvimetalurgia
Authors: Del Valle J. A. , Ruano O. A.
Published: May 2011

Se ha estudiado la presencia de una tensión umbral, en una aleación de magnesio AZ31 de pequeño tamaño de grano conteniendo diferentes cantidades de partículas, procesada por métodos pulvimetalúrgicos. Se observó que el deslizamiento en fronteras de grano es el mecanismo que controla la deformación, en un intervalo amplio de velocidades de deformación y temperaturas. La disminución drástica de la velocidad de deformación, con una pequeña disminución de la tensión, permite deducir la presencia de una tensión umbral. Esta tensión umbral es independiente de la temperatura. En este trabajo se hace un análisis de su presencia y de su dependencia con los parámetros estructurales y mecánicos de las aleaciones.
Influencia del tratamiento térmico en las intercaras y propiedades mecánicas de un laminado multicapa de aluminio
Authors: Cepeda-Jiménez C. M. , Hidalgo P. , Pozuelo M. , Ruano O. A. , Carreño F.
Published: May 2011

En este trabajo se han caracterizado la microestructura y las propiedades mecánicas alrededor de la intercara de un material multicapa de aluminio basado en las aleaciones Al 7075 y Al 2024. Las técnicas empleadas, principalmente, han sido EBSD y ensayos de cizalla para determinar propiedades mecánicas de las intercaras, en función del tiempo de solubilización durante el tratamiento térmico T6. Dicho tratamiento modifica la microestructura de las aleaciones constituyentes adyacentes a la intercara y, por tanto, las propiedades mecánicas de esta. La combinación de la ruta de procesado adecuada mediante laminación en caliente, junto con un tratamiento térmico optimizado conduce a intercaras resistentes, propensas a delaminar y, por ello, a materiales con propiedades mecánicas excelentes.
Evaluación del espesor de capas delgadas mediante análisis EDS y simulación de Monte Carlo
Authors: García J. C. , Peñalba F.
Published: May 2011

En este trabajo se presenta un método de evaluación de espesores de capas delgadas mediante la técnica de energías dispersivas de rayos X (EDS). Las medidas analíticas de las áreas de los picos característicos de los elementos detectados en las capas, obtenidas mediante esta técnica, se complementan con simulaciones de Monte Carlo de las trayectorias de los electrones en el volumen de interacción. Esto, junto con las estimaciones de la intensidad de los picos característicos obtenidos mediante el algoritmo de Bethe, Joy & Luo, posibilita realizar la estimación de los espesores de las muestras analizadas.
Definición de una metodología optimizada para la simulación del desgaste en materiales metálicos
Authors: Cruzado A. , Zabala A. , Urchegui M. A. , Gómez X.
Published: May 2011

La simulación del desgaste mediante el Método de Elementos Finitos (MEF) es una técnica que presenta grandes ventajas para la mejora del diseño de componentes ya que permite reducir el coste que conlleva la experimentación (tiempo de ensayo, materiales, medidas tribológicas). En el caso concreto de la optimización de sistemas multihilo sometidos a fretting, como es el caso de los cables metálicos donde se dan contactos cilindro-cilindro, este método puede resultar especialmente eficiente. Sin embargo, la simulación del desgaste resulta una técnica compleja ya que consta de dos núcleos importantes: por un lado, la resolución del contacto y, por otro, la introducción del modelo de desgaste, requiriendo, para ello, de un coste computacional muy importante. Por ello, en este trabajo se define una metodología a seguir con el fin de optimizar el modelo, en términos de tiempo computacional, para un sistema bloque-cilindro. La metodología definida sería aplicable a todos los modelos de desgaste, de geometrías más complejas. Finalmente, se introduce una técnica que consiste en la introducción de un acelerador de desgaste variable y autoajustable, teniendo en cuenta la evolución de la presión máxima de desgaste y el incremento umbral de desgaste. Esta técnica resulta indispensable en cuerpos sometidos a grandes desgastes, reduciendo el tiempo computacional en un 87 % y un error inferior al 1 %.
Nuevo modelo para la predicción de la microestructura final y los parámetros de recristalización dinámica de materiales metálicos policristalinos. Aplicación a la aleación de magnesio AZ31
Authors: Rieiro I. , Larrea M. T. , Gutiérrez V. , Triviño V. , Carsí M. , Ruano O. A.
Published: May 2011

Se ha partido de una nueva ecuación constitutiva capaz de reproducir las curvas tensión-deformación para cada velocidad de deformación y temperatura. Aplicando esta ecuación se pueden obtener los parámetros característicos de la recristalización dinámica para cada una de las curvas de fluencia. En este trabajo se ha hecho un estudio experimental de los tamaños de grano finales, sus distribuciones de frecuencia y fracciones de área que, junto con los parámetros característicos de la recristalización dinámica, han permitido establecer modelos predictivos para las condiciones finales de microestructura de materiales metálicos policristalinos. El método se ha aplicado a la aleación de magnesio AZ31 deformada en caliente. Se predicen tanto valores promedio de tamaños de grano final como distribuciones de fracciones de área y de frecuencia de los mismos. También, se predicen los parámetros característicos de la recristalización dinámica del material que constituyen elementos de control del proceso de deformación.
Desarrollo y caracterización de un material compuesto de matriz de aluminio 6061 y partículas de TiB2
Authors: Egizabal P. , Merchán M. , García-de-Cortázar M. , Plaza L. M. , Torregaray A.
Published: May 2011

Una de las vías desarrolladas, en los últimos años, para la mejora de las propiedades mecánicas de las aleaciones de aluminio es la de la incorporación de refuerzos cerámicos en forma de partículas cerámicas. El objetivo principal del trabajo ha sido desarrollar el proceso de fabricación de una aleación de aluminio 6061 reforzada con partículas de diboruro de titanio, TiB2, y analizar las propiedades del material obtenido. Se ha observado que el proceso de fabricación planteado, consistente en la fabricación de las partículas por medio del proceso de síntesis autopropagada a alta temperatura SHS (Self propagating high temperature synthesis) y su posterior incorporación a la aleación 6061, es un proceso viable para la fabricación de aleaciones reforzadas adecuadas para la realización de procesos subsiguientes de extrusión o forja. El resultado final es la obtención de un material adecuado para la fabricación de componentes extruidos y que presenta una mejora de sus propiedades de tracción y fatiga, en comparación a la aleación base.
Modelización delmaclado {10Ῑ2} de una chapa laminada de Mg-3%Al-1%Zn
Authors: Jérusalem A. , Fernández A. , Pérez-Prado M. T.
Published: May 2011

Un modelo continuo de plasticidad cristalina, que contempla los mecanismos de auto-endurecimiento y endurecimiento cruzado para los sistemas de maclado y deslizamiento, se ha utilizado para predecir las actividades de deslizamiento y del maclado, así como la evolución de la textura, de una chapa laminada y recocida de la aleación de magnesio Mg-3%Al-1%Zn ensayada en compresión, a lo largo de la dirección de laminación (DL) y en tensión, a lo largo de la dirección normal (DN). Se encontró que la contribución del maclado es mucho más importante cuando la muestra se tensiona a lo lago de DN, lo que da lugar a un cambio fuerte de textura. Se observó una buena correspondencia entre las simulaciones y resultados experimentales recientes.
Aerogeles híbridos y aerogeles bioactivos en compresión uniaxial: un estudio in situ con SAXS
Authors: Morales-Flórez V. , De la Rosa-Fox N. , Piñero M. , Esquivias L.
Published: May 2011

La compleja estructura de los aerogeles híbridos orgánico/inorgánicos está compuesta por una fase inorgánica de sílice, unida mediante enlaces covalentes a una red de cadenas orgánicas. Se han estudiado composites híbridos convencionales y bioactivos, esto es, con una fase activa de calcio añadida. En este trabajo se ha investigado la relación entre la respuesta mecánica y la nanoestructura, con ayuda de un portamuestras específicamente diseñado para el estudio in situ de muestras bajo compresión uniaxial, a la vez que se obtiene el espectro de rayos-X a bajo-ángulo de radiación sincrotrón (SAXS). Los elementos estructurales se pueden describir como núcleos particulados de sílice rodeados de las cadenas orgánicas. Estas, se comprimen en la dirección paralela a la carga pudiéndose establecer una relación entre la compresión uniaxial macroscópica y la deformación de las partículas y poros que forman la estructura.
A Case of Idiopathic Encephalomeningocele
Authors: Petridis Athanasios K. , Doukas Alexandros , Mehdorn Hubertus M.
Published: May 2011

In the present case we report about an encephalomeningocele in an adult female. Since the cause of this medical entity is a congenital fusion defect of the neural tube of the cranial base, most of the encephaloceles occurs in children leading to facial disfigurement. In the rare cases described in adults, rhinorrhea is usually present. Here we present a case of temporobasal encephalomeningocele in a 72-year-old female patient suffering from headaches in the last 4–5 years. No rhinorrhea or other significant neurological symptoms were noticed. No congenital cause was apparent. After diagnostic steps including brain magnetic resonance imaging (MRI), cranial computed tomography (CT) and MR cisternography, an encephalomeningocele was diagnosed. Through a pterional approach this was completely removed. The only symptom the patient complaint about, headache, was eliminated after surgery.
Coexistence of Behçet’s Disease with Ankylosing Spondylitis and Familial Mediterranean Fever: A Rare Occurrence
Authors: Frigui Makram , Kechaou Manel , Jallouli Moez , Kaddour Neila , Chaabouni Habiba Bouhamed , Bahloul Zouhir
Published: May 2011

Behçet's disease (BD) and familial Mediterranean fever (FMF), which are two separate diseases sharing some clinical features, may also coexist in the same patient. Further investigations are needed to understand whether this coexistence is due to either chance or geographical distribution patterns of these diseases or to common etiopathogenetic characteristics. Spondylarthritis as part of the clinical picture in these two diseases has been questioned and probably it is not a prominent characteristic of any of them. We report a 35- year-old Tunisian man who had an association of BD, FMF and Human Leukocyte Antigen (HLA) B27 positive ankylosing spondylitis. Although that spondylarthritis is an infrequent joint involvement of FMF and BD, it must be looked for in case of association of these diseases.
Primary gastric chorioadenocarcinoma: a needle in a haystack
Authors: Shastri Aditi , Daver Naval G. , Hayes Teresa G.
Published: May 2011

Primary gastric chorioadenocarcinoma (PGC) is an exceedingly rare neoplasm which is often misdiagnosed as gastric adenocarcinoma at presentation. A markedly elevated serum beta human chorionic gonadotrophin (Beta HCG) level is a characteristic feature of this tumor. A 44 year old white male presented with generalized abdominal pain and fullness, tarry black stools and weight loss of 3 months duration. Medical work-up including imaging with CT scans revealed the presence of a gastric mass and multiple liver metastases. Tumor markers were significant for a Beta human chorionic gonadotrophin (Beta HCG) of 23717.5 MIU/ML. Scrotal ultrasound did not show the presence of a testicular mass. Upper GI endoscopy with biopsy was positive for a poorly differentiated adenocarcinoma with Beta HCG staining on immunohistochemistry. The patient was diagnosed with metastatic PGC. He received four cycles of chemotherapy with Bleomycin, Etoposide and Cisplatinum. At the end of the fourth cycle, Beta HCG was 23 MIU/ML. CT scan for restaging, however showed an increase in the size of the metastatic lesions. The patient subsequently became profoundly pancytopenic, developed disseminated intravascular coagulation (DIC) and expired 12 months after initial presentation. PGC genetically and morphologically represents an adenocarcinoma and a choriocarcinoma. The significance of an elevated serum Beta HCG is controversial and it may have a role in evaluating response to treatment and tumor recurrence. Curative resection, appropriate chemotherapy and the absence of metastatic lesions is associated with improved survival. Hence, a high index of suspicion must be maintained to diagnose this tumor correctly at presentation and tailor therapy accordingly.
Andries van Aarde’s Matthew Interpretation
Authors: Le Roux Jurie H.
Published: May 2011

This article focused on Andries van Aarde’s interpretation of the Gospel of Matthew. It argues that Van Aarde has changed his approach to Matthew in the course of time. At the beginning of his career he focused on structural analysis and even made a contribution to the Gattung problem from a structural perspective. Then his attention shifted to narrative criticism and social-scientific criticism. Van Aarde’s consistent narratological interpretation of Matthew enabled him to identify Matthew’s ideology and to determine the way in which it took shape on the surface structure. This narratological investigation also shed new light on, amongst others, the parables, the characters and the problem of direct and indirect discourse. To conclude the article, some critical statements with regard to the historical understanding of the Gospel of Matthew were formulated.
Seeing the world through the eyes of Andries van Aarde: Radical inclusivity
Authors: Jackson Glenna S.
Published: May 2011

In the article the author reflected on her personal and existential experience of a journey to Egypt, and how this highlights radical inclusivity. The article focused on the issues of the violence of poverty, the history of Coptic Christianity and the role of women within this tradition. The article touched on aspects such as ‘women monks’, ecclesiastical hierarchy in modern Coptic Christianity, and the ordination of clergy. It also considered the perspective of ‘social hierarchy’ and ‘spiritual or divine hierarchy’.
The divine favour of the unworthy: When the fatherless son meets the Black Messiah
Authors: Boesak Allan A.
Published: May 2011

This article engages with Andries van Aarde’s 2001 work on the historical Jesus, Fatherless in Galilee: Jesus as Child of God. It poses the question whether Van Aarde succeeds in overcoming the shortcomings of Western, Euro-centric, male dominated scholarship and making a different kind of conversation with non-Western Christians possible. The article explores the new ways in which Van Aarde speaks of the historical Jesus and interrogates the consequences of his main thesis, namely that to understand the historical Jesus properly, one needs to understand the most determining fact of Jesus’ life, specifically his fatherlessness. The article finds that Van Aarde’s fatherless Jesus opens up heretofore unexplored possibilities for the ongoing discussion with liberation theologies, in particular Black liberation theology. However, it raises the question whether Van Aarde does justice to his own new insights by interacting with Western theological scholarship alone. The fatherless Jesus and the Black Messiah meet in South Africa, where the cause of the fatherless Jesus has been so shamefully betrayed and where the divine favour of the Black Messiah needs to be gloriously embraced.
Quorum sensing and Bacterial Pathogenicity: From Molecules to Disease
Authors: Deep Antariksh , Chaudhary Uma , Gupta Varsha
Published: May 2011

Quorum sensing in prokaryotic biology refers to the ability of a bacterium to sense information from other cells in the population when they reach a critical concentration (i.e. a Quorum) and communicate with them. The "language" used for this intercellular communication is based on small, self-generated signal molecules called as autoinducers. Quorum sensing is thought to afford pathogenic bacteria a mechanism to minimize host immune responses by delaying the production of tissue-damaging virulence factors until sufficient bacteria have amassed and are prepared to overwhelm host defense mechanisms and establish infection. Quorum sensing systems are studied in a large number of gram-negative bacterial species belonging to α, β, and γ subclasses of proteobacteria. Among the pathogenic bacteria, Pseudomonas aeruginosa is perhaps the best understood in terms of the virulence factors regulated and the role the Quorum sensing plays in pathogenicity. Presently, Quorum sensing is considered as a potential novel target for antimicrobial therapy to control multi/all drug-resistant infections. This paper reviews Quorum sensing in gram positive and gram negative bacteria and its role in biofilm formation.
Human Immunodeficiency Virus Infection Among Tuberculosis Patients in Mumbai
Authors: Sawant Sandhya S , Agrawal Sachee R , Shastri Jayanthi S , Pawaskar Medha , Kadam Pradeep
Published: May 2011

Background: Human Immunodeficiency Virus (HIV) is the most powerful risk factor for the progression of Mycobacterium tuberculosis infection to Tuberculosis (TB) disease. TB accelerates the progression of HIV infection to AIDS and shortens the survival of such patients.

Aim: To determine the seroprevalence of HIV infection among TB confirmed patients in a tertiary care center in Mumbai in view of the significance of HIV in TB. Its association with gender and age was also determined.

Materials and Methods: Blood samples were collected by venipuncture from 432 TB patients and their HIV status was determined. HIV antibody detection was carried out as per Strategy III, National AIDS Control Organisation (NACO) guidelines. Statistical analysis was carried out by applying the Chi-square test.

Results and Conclusion: Of the 432 patients screened, 9% (39) were HIV positive. The prevalence of co-infection was higher among females (9.4%) than the male (8.7%) patients and highest amongst those aged 21to40 years (13.7%). Co-infection was found to be statistically highly associated with age (p < 0.05). This high prevalence calls for routine screening of TB patients for HIV infection.
Pancytopenia: A Clinico Hematological Study
Authors: N. Gayathri B , Rao Kadam Satyanarayan
Published: May 2011

Background: Pancytopenia is a relatively common hematological entity. It is a striking feature of many serious and life-threatening illnesses, ranging from simple drug-induced bone marrow hypoplasia, megaloblastic anemia to fatal bone marrow aplasias and leukemias. The severity of pancytopenia and the underlying pathology determine the management and prognosis. Thus, identification of the correct cause will help in implementing appropriate therapy.

Objectives: To study the clinical presentations in pancytopenia due to various causes; and to evaluate hematological parameters, including bone marrow aspiration.

Materials and Methods: It was a prospective study, and 104 pancytopenic patients were evaluated clinically, along with hematological parameters and bone marrow aspiration in Hematology Unit, Department of Pathology, JJMMC, Davanagere, during the period of September 2005 to September 2007.

Results: Among 104 cases studied, age of patients ranged from 2 to 80 years with a mean age of 41 years, and male predominance. Most of the patients presented with generalized weakness and fever. The commonest physical finding was pallor, followed by splenomegaly and hepatomegaly. Dimorphic anemia was the predominant blood picture. Bone marrow aspiration was conclusive in all cases. The commonest marrow finding was hypercellularity with megaloblastic erythropoiesis. The commonest cause for pancytopenia was megaloblastic anemia (74.04%), followed by aplastic anemia (18.26%).

Conclusion: The present study concludes that detailed primary hematological investigations along with bone marrow aspiration in cytopenic patients are helpful for understanding disease process and to diagnose or to rule out the causes of cytopenia. These are also helpful in planning further investigations and management.
Inducible Clindamycin Resistance in Staphylococcus aureus Isolated from Clinical Samples
Authors: Prabhu Kavitha , Rao Sunil , Rao Venkatakrishna
Published: May 2011

Introduction: The resistance to antimicrobial agents among Staphylococci is an increasing problem. This has led to renewed interest in the usage of Macrolide-Lincosamide-Streptogramin B (MLS B ) antibiotics to treat Staphylococcus aureus (S. aureus) infections. The resistance to macrolide can be mediated by msr A gene coding for efflux mechanism or via erm gene encoding for enzymes that confer inducible or constitutive resistance to MLS B antibiotics. In vitro routine tests for clindamycin susceptibility may fail to detect inducible clindamycin resistance due to erm genes resulting in treatment failure, thus necessitating the need to detect such resistance by a simple D test on a routine basis.

Materials and Methods : One hundred and ninety S. aureus isolates were subjected to routine antibiotic susceptibility testing including oxacillin (1 µg) and cefoxitin (30 µg) by modified Kirby Bauer disc diffusion method. Inducible resistance to clindamycin in S. aureus was tested by ′D test′ as per CLSI guidelines.

Results: Twenty (10%) isolates showed inducible clindamycin resistance, 18 (9%) showed constitutive resistance while remaining 16 (8%) showed MS phenotype. Inducible resistance and constitutive resistance were found to be higher in MRSA as compared to MSSA (20%, 16% and 6%, 6%, respectively).

Conclusion : Clindamycin is kept as a reserve drug and is usually advocated in severe MRSA infections depending upon the antimicrobial susceptibility results. This study showed that D test should be used as a mandatory method in routine disc diffusion testing to detect inducible clindamycin resistance in Staphylococci for the optimum treatment of patients.
Lipoprotein (a) and other Lipid Profile in Patients with Thrombotic Stroke: Is it a Reliable Marker?
Authors: Nagaraj Shashidhar K , Pai Pareenta , Bhat Gopalakrishna , A. Hemalatha
Published: May 2011

Background: Cerebrovascular disease (CVD) and coronary heart disease (CHD) cause 40%-50% of deaths in developed countries with CVD causing 10%-12% of deaths. Though increased Lipoprotein (a) is a risk factor in developing CHD, its role is poorly defined in etiopathogenesis of CVD.

Aims: To find the association of lipoprotein (a) and lipid profile in thrombotic stroke patients after acute phase.

Settings and Design: The study was conducted at Kasturba Medical College, Manipal. Twenty one cases of thrombotic stroke and 18 cases of age and sex matched controls were taken for the study. Informed consent was taken from both case and control.

Materials and Methods: Overnight fasting sample was collected from both case and control. Serum was separated and parameters such as total cholesterol, triglycerides, high density lipoproteins-C, low density lipoprotein-C, lipoprotein (a), fasting blood sugars were estimated. Statistical analysis: Data were analyzed by SPSS software, Student′s t-test, standard deviation (SD), and standard error of mean (SEM), P-value <0.05 is considered to be significant.

Results: In this study, we found no statistical significant differences in serum lipid and lipoprotein (a) profile between controls and thrombotic stroke patients.

Conclusions: Highest frequency (38%) of stroke was found in the age group of 7080 years. There were other associated risk factors such as diabetes in five cases (24%), hypertension in nine cases (43%), and family history of stroke in four cases. However, further studies are required to evaluate the importance of serum Lp(a) estimation in the assessment as a risk factor for thrombotic stroke.
Horizontal Transfer of Antimicrobial Resistance by Extended-Spectrum β Lactamase-Producing Enterobacteriaceae
Authors: Vaidya Varsha K
Published: May 2011

Background: The purpose of this work was to study the acquisition of new antibiotic-resistant genes carried by extended spectrum β-lactamase (ESBL)-producing Enterobacteriaceae via horizontal transfer to understand their rampant spread in the hospitals and in the community.

Materials and Methods: A retrospective analysis of 120 ESBL screen-positive isolates of Escherichia coli and Klebsiella pneumoniae, which were subjected to antimicrobial susceptibility testing, was carried out. The Double Disc Synergy Test (DDST) and Inhibitor-Potentiation Disc Diffusion Test (IPDD) were employed for confirmation of ESBL activity. The transferability of the associated antibiotic resistance for amoxicillin, amikacin, gentamicin, cefotaxime and ceftriaxone was elucidated by intra- and intergenus conjugation in Escherichia coli under laboratory as well as under simulated environmental conditions. Transformation experiments using plasmids isolated by alkaline lysis method were performed to study the transferability of resistance genes in Klebsiella pneumoniae isolates.

Results : ESBL production was indicated in 20% each of the Escherichia coli and Klebsiella pneumoniae isolates. All the ESBL isolates showed co- resistance to various other groups of antibiotics, including 3GC antibiotics, though all the isolates were sensitive to both the carbapenems tested. Conjugation-mediated transfer of resistance under laboratory as well as environmental conditions at a frequency of 3-4 x 10-5 , and transformation-mediated dissemination of cefotaxime and gentamicin resistance shed light on the propensity of ESBL producers for horizontal transfer.

Conclusions: The transfer of resistant markers indicated availability of a large pool of resistance genes in the hospital setting as well as in the environment, facilitating long-term persistence of organisms.
Actinomycetes Mycetoma
Authors: Hogade Sumati , C. Metgud S ,   Swoorooparani
Published: May 2011

Mycetoma is a chronic infection, frequently seen in tropical and sub-tropical countries and is considered as an occupational disease. Nocardia species though it can infect immunocompetent individuals, it most commonly affects immunocompromised patients. A 50-year-old male, farmer presented to our hospital with serosanguineous discharging swelling over the dorsum of right foot. We have isolated Nocardia asteroides from the tissue sample. Speciation of this isolate was carried out based on phenotypic methods. Hereby we report a case of Actinomycetes Mycetoma in an immunocompetent individual.
A Rare Case of Fungal Maxillary Sinusitis due to Paecilomyces lilacinus in an Immunocompetent Host, Presenting as a Subcutaneous Swelling
Authors: Permi Harish S , Y. Sunil kumar , Karnaker Vimal K , L. Kishan Prasad H , Teerthanath S , Bhandary Satheesh Kumar
Published: May 2011

Paecilomyces is a colonizing fungal species which usually causes keratitis, endocarditis, sinusitis, nephritis, fungemia, cutaneous, and subcutaneous infections in immunocompromised host. Very rarely, it causes similar infection in immunocompetent host without any risk factors. We report a case of maxillary sinusitis due to Paecilomyces lilacinus in a 65-year-old immunocompetent male, who presented with a subcutaneous swelling below the left eye. The lesion was excised by surgery and treated with itraconazole for 6 months based on culture and sensitivity. After 1 year of follow up, he is free of symptoms with no evidence of recurrence.
Uncommon Manifestations of Endocervical Malignant Mixed Mullerian Tumor with Incidental Bilateral Fallopian Tube Carcinoma
Authors: L. Kishan Prasad H , Makannavar J H , Shetty Jayaprakash , Patil Channappa , Permi Harish S ,   Vinutha
Published: May 2011

A 43-year-old perimenopausal lady presented with bleeding per vagina and lower abdominal pain. On evaluation, she had cervical polyp, which expelled spontaneously during the per speculum examination. Histopathology revealed malignant mixed Mullerian tumor. Extended hysterectomy with salphingo oophorectomy was carried out, which showed bilateral fallopian tube carcinoma and leiomyoma uterus. The patient was treated with carboplatin regime and found to be disease-free for 1 year. This case presented because of a rare combination of the lesions.
Spinal shortening and monosegmental posterior spondylodesis in the management of dorsal and lumbar unstable injuries
Authors: Aly Tarek A
Published: May 2011

Introduction: Patients with spinal injuries have been treated in the past by laminectomy in an attempt to decompress the spinal cord. The results have shown insignificant improvement or even a worsening of neurologic function and decreased stability without effectively removing the anterior bone and disc fragments compressing the spinal cord. The primary indication for anterior decompression and grafting is narrowing of the spinal canal with neurologic deficits that cannot be resolved by any other approach. One must think of subsequent surgical intervention for increased stability and compressive posterior fusion with short-armed internal fi xators. Aim: To analyze the results and efficacy of spinal shortening combined with interbody fusion technique for the management of dorsal and lumbar unstable injuries. Materials and Methods: Twenty-three patients with traumatic fractures and or fracture-dislocation of dorsolumbar spine with neurologic deficit are presented. All had radiologic evidence of spinal cord or cauda equina compression, with either paraplegia or paraparesis. Patients underwent recapping laminoplasty in the thoracic or lumbar spine for decompression of spinal cord. The T-saw was used for division of the posterior elements. After decompression of the cord and removal of the extruded bone fragments and disc material, the excised laminae were replaced exactly in situ to their original anatomic position. Then application of a compression force via monosegmental transpedicular fixation was done, allowing vertebral end-plate compression and interbody fusion. Results: Lateral Cobb angle (T10–L2) was reduced from 26 to 4 degrees after surgery. The shortened vertebral body united and no or minimal loss of correction was seen. The preoperative vertebral kyphosis averaged +17 degrees and was corrected to +7 degrees at follow-up with the sagittal index improving from 0.59 to 0.86. The segmental local kyphosis was reduced from +15 degrees to −3 degrees. Radiography demonstrated anatomically correct reconstruction in all patients, as well as solid fusion. Conclusion: This technique permits circumferential decompression of the spinal cord through a posterior approach and posterior interbody fusion.
Placebo - More hatred than love
Authors: Hong-Liang Zhang
Published: May 2011

A placebo is a sham medical intervention that can produce a placebo eff ect. Laboratory evidence supports the existence of several mechanisms of placebo eff ects in both healthy population and patients with a variety of medical conditions. The ethics of placebos have long been debated. However, accumulating ethical concern has arisen from the worldwide use of placebo in randomized control trials (RCTs), which may render their participants without early and optimal treatment. Although the pilgrimage of placebo is still on the way, refi nement of controls in RCTs is worth paying new attention to.
Benign paroxysmal positional vertigo
Authors: Guo Xiang-Dong
Published: May 2011

Benign paroxysmal positional vertigo (BPPV) is a common clinical disorder characterized by brief recurrent spells of vertigo often brought about by certain head position changes as may occur with looking up, turning over in bed, or straightening up after bending over. It is important to understand BPPV not only because it may avert expensive and often unnecessary testing, but also because treatment is rapid, easy, and eff ective in >90% of cases. The diagnosis of BPPV can be made based on the history and examination. Patients usually report episodes of spinning evoked by certain movements, such as lying back or getting out of bed, turning in bed, looking up, or straightening after bending over. At present, the generally accepted recurrence rate of BPPV after successful treatment is 40%–50% at 5 years of average follow-up. There does appear to be a subset of individuals prone to multiple recurrences..
The effect of right or left handedness on caries experience and oral hygiene
Authors: Çakur Binali , Yildiz Mehmet , Dane Şenol , Zorba Yahya Orçun
Published: May 2011

Background: There is an indisputable relationship between tooth decay and oral hygiene. Caries can only be prevented by keeping tooth decay at bay. In several prophylactic methods, brushing is the most important. Brushing efficiency is directly related to an individuals’ manual dexterity. Objective: To investigate whether there were differences in oral hygiene and caries prevalence between right- and left-handers. Materials and Methods: Forty-six elementary school students were included in the study. The subjects were 30 males and 16 females, ranging in age from 11 to 13 years. Handedness was ascertained by using the Edinburgh Handedness Scale. All students were examined intraorally. During this examination, the necessary values to determine oral hygiene status and to determine caries prevalence were recorded. Results: It was observed that subjects who used their right hands were in a better position in terms of oral hygiene than those using the left (P < 0.01). In terms of caries prevalence, however, averages for right-handed individuals were lower than those for left-handed subjects, although the difference was not statistically significant. Conclusions: It can be stated that the right-handed individuals have better oral hygiene and the lower incidence of caries because of their better manual dexterity and brush efficiency. So, dentists should consider better manual dexterity and brush efficiency in right-handed individuals before treatment planning. However, future well-designed neurologic studies involving larger numbers of subjects will be necessary to confirm the findings of this study and to understand more about the effects of handedness on oral hygiene performance.
Rehabilitation for cerebral palsy: Analysis of the Australian rehabilitation outcome dataset
Authors: Amatya Bhasker , Khan Fary
Published: May 2011

Objective: To examine the outcome of inpatient rehabilitation for cerebral palsy (CP), using the Australian Rehabilitation Outcomes Center (AROC) database. Materials and Methods: De-identified data from the AROC database was analyzed for all rehabilitation admissions during 2003 – 2008, using four classes for the functional level. The outcomes included: Functional Independence Measure (FIM) scores, FIM efficiency, hospital length of stay (LOS), and discharge destination. Results: Of 141 case episodes 56.7% were female, mean age 48.5 years, 87.2% were discharged to the community and 64.5% (n = 91) were in the lowest functional classes (217, 218, and 219). The majority of CP patients were treated in the public hospital system (66.7% versus 33.3%), and had a slightly longer LOS compared with those treated in private facilities (22.6 versus 17.9 days, mean difference - 4.7 days, 95% CI - 9.2 to - 0.2, P = 0.041). The FIM for all classes (216 – 218) showed significant functional improvement during the admission (P = 0.001). As expected those in the most functionally impaired classes showed most change (FIM change: 16.6 in class 217, 15.3 in class 218). FIM efficiency was the highest in classes 217 compared to the other classes. The year-to-year trend demonstrated a mixed pattern for hospital LOS and was not significant (P = 0.492). Conclusion: The AROC dataset is a valuable research tool for describing rehabilitation outcomes. However, more specific information needs to be collected alongside the core AROC data, to allow a more meaningful evaluation of outcomes for CP rehabilitation..
Headache in a 27-year-old man: Bilateral serous retinal detachment
Authors: Yaghoubi Gholamhossein , Heydari Behrouz , Yaghoobi Mohammad Ali
Published: May 2011

A 27-year-old man with a complaint of headache, tinnitus, and visual obscuration presented to a neurologist. Neurologic evaluations, including MRI and CT scan, were within normal limit. The prescribed medicines were propranolol, sumatriptin, valproate sodium, and dexamethasone. Ophthalmic examination was associated with reduction of visual acuity of eyes, bilateral uveitis, and serous retinal detachment. The most probable diagnosis was Vogt–Koyanagi–Harada (VKH) disease. Prescribing high-dose oral steroid and acetazolamide-improved systemic and ocular symptoms. Although HLAB5 is positive in Behçet disease, it also may be seen in VKH.
Magnetic resonance “flip-flop” in idiopathic intracranial hypertension
Authors: George Uttam , Bansal Geetika , Pandian Jeyaraj
Published: May 2011

Idiopathic intracranial hypertension (IIH) is a headache syndrome with raised CSF pressure in the absence of an intracranial mass lesion. Though earlier confined to excluding intracranial lesions, magnetic resonance imaging (MRI) in recent years has been shown to identify intracranial changes from prolonged raised CSF pressure, suggestive of IIH. We present the MRI and TOF (time-of-flight) venography findings involving the orbit, sella tursica and cerebral venous structures in a 45-year-old lady with IIH and illustrate their reversibility (“flip-fl op”) following CSF drainage. Our case highlights the role of imaging in evaluation and follow-up of patients with IIH, without the need for repeated lumbar punctures to monitor pressures.
Imaging of the Bursae
Authors: Hirji Zameer , Hunjun Jaspal S , Choudur Hema N
Published: May 2011

When assessing joints with various imaging modalities, it is important to focus on the extraarticular soft tissues that may clinically mimic joint pathology. One such extraarticular structure is the bursa. Bursitis can clinically be misdiagnosed as joint-, tendon- or muscle-related pain. Pathological processes are often a result of inflammation that is secondary to excessive local friction, infection, arthritides or direct trauma. It is therefore important to understand the anatomy and pathology of the common bursae in the appendicular skeleton. The purpose of this pictorial essay is to characterize the clinically relevant bursae in the appendicular skeleton using diagrams and corresponding multimodality images, focusing on normal anatomy and common pathological processes that affect them. The aim is to familiarize radiologists with the radiological features of bursitis.
Carbon balance of South Asia constrained by passenger aircraft CO2 measurements
Authors: Patra P. K. , Niwa Y. , Schuck T. J. , Brenninkmeijer C. A. M. , Machida T. , Matsueda H. , Sawa Y.
Published: May 2011

Abstract. Quantifying the fluxes of carbon dioxide (CO2) between the atmosphere and terrestrial ecosystems in all their diversity, across the continents, is important and urgent for implementing effective mitigating policies. Whereas much is known for Europe and North America for instance, in comparison, South Asia, with 1.6 billion inhabitants and considerable CO2 fluxes, remained terra incognita in this respect. We use regional measurements of atmospheric CO2 aboard a Lufthansa passenger aircraft between Frankfurt (Germany) and Chennai (India) at cruise altitude, in addition to the existing network sites for 2008, to estimate monthly fluxes for 64-regions using Bayesian inversion and transport model simulations. The applicability of the model's transport parameterization is confirmed using SF6, CH4 and N2O simulations for the CARIBIC datasets. The annual amplitude of carbon flux obtained by including the aircraft data is twice as large as the fluxes simulated by a terrestrial ecosystem model that was applied to prescribe the fluxes used in the inversions. It is shown that South Asia sequestered carbon at a rate of 0.37 ± 0.20 Pg C yr−1 (1 Pg C = 1015 g of carbon in CO2) for the years 2007 and 2008. The seasonality and the strength of the calculated monthly fluxes are successfully validated using independent measurements of vertical CO2 profiles over Delhi and spatial variations at cruising altitude over Asia aboard Japan Airlines passenger aircraft.
Statistical dynamics of tropical wind in radiosonde data
Authors: Koh T.-Y. , Djamil Y. S. , Teo C.-K.
Published: May 2011

Abstract. Weibull distributions were fitted to wind speed data from radiosonde stations in the global tropics. A statistical theory of independent wind contributions was proposed to partially explain the shape parameter k obtained over Malay Peninsula and the wider Equatorial Monsoon Zone. This statistical dynamical underpinning provides some justification for using empirical Weibull fits to derive wind speed thresholds for monitoring data quality. The regionally adapted thresholds retain more useful data than conventional ones defined from taking the regional mean plus three standard deviations. The new approach is shown to eliminate reports of atypically strong wind over Malay Peninsula which may have escaped detection in quality control of global datasets as the latter has assumed a larger spread of wind speed. New scientific questions are raised in the pursuit of statistical dynamical understanding of meteorological variables in the tropics.
Global and regional effects of the photochemistry of CH3O2NO2: evidence from ARCTAS
Authors: Browne E. C. , Perring A. E. , Wooldridge P. J. , Apel E. , Hall S. R. , Huey L. G. , Mao J. , Spencer K. M. , Clair J. M. St. , Weinheimer A. J. , Wisthaler A. , Cohen R. C.
Published: May 2011

Abstract. Using measurements from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) experiment, we show that methyl peroxy nitrate (CH3O2NO2) is present in concentrations of ~5–15 pptv in the springtime arctic upper troposphere. We investigate the regional and global effects of CH3O2NO2 by including its chemistry in the GEOS-Chem 3-D global chemical transport model. We find that at temperatures below 240 K inclusion of CH3O2NO2 chemistry results in decreases of up to ~20 % in NOx, ~20 % in N2O5, ~5 % in HNO3, ~2 % in ozone, and increases in methyl hydrogen peroxide of up to ~14 %. Larger changes are observed in biomass burning plumes lofted to high altitude. Additionally, by sequestering NOx at low temperatures, CH3O2NO2 decreases the cycling of HO2 to OH, resulting in a larger upper tropospheric HO2 to OH ratio. These results may impact some estimates of lightning NOx sources as well as help explain differences between models and measurements of upper tropospheric composition.