bluuebunny/crossref_metadata_2025 huggingface dataset:
Efectos gammágenos del cobre en los aceros inoxidables 18Cr8Ni
Authors: Botella J. , Hierro P. , Merino C.
Published: October 2010

A partir de una serie de 22 lingotes de 40 kg de aceros inoxidables típicos 18Cr8Ni, con concentraciones variables de cobre entre 0,6 y 3,0 % en masa, se mide la ferrita δ mediante un medidor de ferrita y se deduce para el cobre un equivalente en níquel de 0,27, a la vez que se establecen ciertas diferencias entre los contenidos de ferrita δ medida y la deducida según DeLong -excluida la acción gammágena del cobre- por el hecho de solidificar en lingotes en vez de la típica solidificación de soldaduras.
Criterio para la limitación del desgaste de herramientas en el punzonado de chapa de acero inoxidable 18-8
Authors: Faura F. , López J. , Sanes J.
Published: October 2010

El presente artículo desarrolla un criterio para la limitación del desgaste en procesos de punzonado de chapa de acero inoxidable 18-8. Se han considerado diferentes factores, tales como longitud de la herramienta, juego de corte o materiales, para establecer dicho criterio. El objetivo final es determinar el máximo número de operaciones entre dos reacondicionados consecutivos de la herramienta hasta el completo deterioro de la misma. En consecuencia, se ha obtenido el máximo número posible de operaciones que puede realizarse en unas condiciones de trabajo determinadas para llegar a un desgaste económicamente aceptable. Los resultados obtenidos por el presente método tienen una excelente correspondencia con estudios teóricos y experimentales previos. Los ensayos fueron realizados utilizando una prensa de 20 t y una velocidad de 150 golpes/min para juegos de corte comprendidos entre un 5 y 20 % del espesor de la chapa. El material del punzón usado en los ensayos fue un AISI A2 con diámetros comprendidos entre 6 y 14 mm.
Caracterización estructural de vidrios con altos contenidos de óxidos de hierro obtenidos a partir de un residuo de la hidrometalurgia del zinc
Authors: Romero M. , Rincón J. María , Mûsik S. , Kozhukharov W.
Published: October 2010

En este trabajo se ha llevado a cabo la caracterización estructural de vidrios con altos contenidos de óxidos de hierro obtenidos por fusión de un residuo industrial de goethita procedente de la hidrometalurgia del zinc con otras materias primas (dolomita y casco de vidrio). El estudio estructural se ha realizado por difracción de rayos-X (DRX), difracción de rayos-X por dispersión amorfa (RDF) y espectroscopia Mössbauer, determinándose las distancias interatómicas, el estado de oxidación y la coordinación de los átomos de hierro en este nuevo tipo de vidrios.
Influencia de los dispersoides en el comportamiento en fluencia de materiales de aluminio reforzados por dispersión
Authors: Carreño F. , Ruano O. A.
Published: October 2010

Se estudió el comportamiento en fluencia del material solidificado rápidamente Al-6,5%Fe-0,6%V-1,3%Si, reforzado por dispersión que contenía una fracción de volumen de dispersoides de 16 %, mediante ensayos de tracción a altas temperaturas desde 483 a 821 K. Las velocidades de deformación impuestas variaron desde 2,5∙10-6 to 10-2s-1. La microestructura, que era muy fina, estaba formada por granos submicrométricos y pequeños dispersoides redondeados y duros de unos 54 nm. El comportamiento en fluencia se caracterizó por altos exponentes de la tensión aparente y altas energías de activación aparentes que no se predicen con exactitud por modelos de la literatura. Por ello, se ha desarrollado una ecuación de fluencia que describe el comportamiento del material de base aluminio reforzado por dispersión y de otros materiales de microestructura similar. La ecuación propuesta es una generalización de ecuaciones de fluencia convencionales por movimiento de dislocaciones y no emplea una tensión umbral.
Inhibidores de escaso impacto medioambiental. Sistemas basados en tierras raras
Authors: Aballe A. , Bethencourt M. , Botana F. J. , Marcos M. , Pérez J. , Rodríguez M. A.
Published: October 2010

Se estudia el comportamiento de los cloruros de lantano, cerio y samario como inhibidores de los procesos de corrosión uniforme y por picaduras de los aceros inoxidables AISI 434 y AISI 304 y de la aleación de aluminio AA 5083 en disoluciones aireadas de NaCl al 3,5 %. Utilizando técnicas electroquímicas como polarización lineal y cíclica, se ha podido evaluar el poder inhibidor de estas sustancias. El mejor comportamiento inhibidor se ha obtenido para una concentración de 500 ppm de CeCl3, si bien para los aceros se obtienen resultados del mismo orden para 500 ppm de LaCl3. Con la ayuda de microscopía electrónica de barrido y espectroscopia de dispersión de energía se ha podido confirmar el carácter catódico del mecanismo de inhibición que tiene lugar en el proceso.
Influencia de la microestructura del cobre comercial sobre los procesos de formación de la pátina gris artificial
Authors: Vera R. , Pulgar J. , Olguín A.
Published: October 2010

El cobre comercial se sometió a tratamiento termomecánico a fin de estudiar su influencia sobre la velocidad de formación artificial de pátina verde por inmersión, así como sobre el espesor y adherencia al sustrato metálico de los productos de corrosión formados. El tratamiento termomecánico permitía la obtención de muestras de 9 a 60 μm de tamaño de grano. Estas muestras se sometieron a un ataque acelerado por inmersión en un baño electrolítico para obtener la pátina verde. Sobre el material de menor tamaño de grano se puede observar una pátina de elevado espesor y gran adherencia, textura fina y morfología homogénea. A partir de los ensayos electroquímicos se estableció que la corriente de pasivación disminuía para tamaños de grano decrecientes. Estos resultados son consecuentes con la pequeña porosidad presentada por la pátina, lo que incrementa su valor protector. El material subyacente no presentó ataque localizado.
Diagrama de Recristalización-Precipitación-Tiempo-Temperatura (RPTT) de un acero microaleado al vanadio
Authors: Quispe A. B. , Medina S. F.
Published: October 2010

Se describe un método desarrollado en el CENIM, que permite estudiar la interacción de la recristalización- precipitación inducida por deformación de un acero microaleado al vanadio. Mediante ensayos de torsión, y aplicando el método back extrapolation, se ha determinado la fracción recristalizada a diferentes temperaturas. Cuando la precipitación comienza, la fracción recristalizada se desvía de la ecuación de Avrami y esto permite conocer el instante en que la precipitación comienza (Ps) y el instante en que termina (Pf). De este modo, se pueden trazar los diagramas Recristalización- Precipitación- Tiempo-Temperatura (RPTT), que muestran gráficamente la interacción Recristalización-Precipitación y que simultáneamente permiten la determinación de la temperatura crítica de recristalización estática (SCRT). Dicha temperatura crítica representa el límite entre las dos fases, antes y después de la precipitación.
Modelo de difusión de cloruros en las estructuras de hormigón armado expuestas en la Península de Yucatán (México)
Authors: Castañeda H. , Castro P. , González C. , Gesescá J.
Published: October 2010

La corrosión del acero de refuerzo es una de las causas que reduce la vida en servicio de las estructuras de hormigón, especialmente en las zonas costeras. Este fenómeno, en atmósferas marinas, se produce como consecuencia de la llegada de iones cloruro a la superficie de la barra por difusión o capilaridad. La vida útil de una estructura se puede dividir en dos períodos: uno de iniciación, durante el cual el acero se mantiene pasivo como resultado del contacto con un medio de pH alcalino, en el cual los iones agresivos penetran el hormigón en dirección al acero, y otro período de propagación, que se inicia cuando la concentración de los iones cloruro en la superficie del acero excede de un cierto nivel crítico. El propósito de este trabajo es presentar un modelo, basado en la segunda ley de Fick, que permita estudiar la difusión de los iones cloruro en un medio marino durante el período de iniciación. Se toma en consideración tanto la variabilidad de los coeficientes de difusión como los parámetros inherentes al hormigón, durante un tiempo de exposición de 2 años en las condiciones ambientales prevalecientes en la Península de Yucatán (México). Para la resolución del conjunto de ecuaciones a que da lugar el modelo se ha utilizado el método numérico de las diferencias finitas, teniéndose en cuenta la no linealidad del problema. Los valores obtenidos a partir del modelo se han comparado con los experimentales para así comprobar la efectividad y viabilidad del modelo propuesto.
Transferencia de calor en la colada continua de aceros. II parte. Enfriamiento secundario
Authors: Cicutti C.
Published: October 2010

La solidificación del acero iniciada en el molde continúa en la zona de enfriamiento secundario de la máquina donde el calor es extraído, principalmente por la incidencia del agua de los rociadores, la radiación al medio ambiente, el contacto con los rodillos y el agua acumulada en ellos. En este trabajo se revisa cada uno de estos mecanismos determinando, en los casos en que es posible, valores cuantitativos de los mismos. Además, se analizan los distintos métodos empleados para medir el avance del espesor solidificado en la máquina de colada continua. Por último, se discute la incidencia del enfriamiento secundario en la calidad final de los productos colados.
Producción de arrabio en los países de la Unión Europea
Authors: García L. , Cores A. , Formoso A. , Babich A.
Published: October 2010

El aumento continuo de la competitividad en la industria siderúrgica hace necesaria la optimización de los recursos y materias primas empleados. Este hecho afecta de igual forma a la fabricación de arrabio en horno alto y a su principal combustible, el coque metalúrgico. De ahí la gran importancia que adquiere el desarrollo de técnicas que faciliten mejoras en los índices de operación del horno alto. En este trabajo se analizan los últimos desarrollos aplicados al proceso del horno alto en los países de la Unión Europea.
Using integrated near‐surface geophysical surveys to aid mapping and interpretation of geology in an alluvial landscape within a 3D soil‐geology framework
Authors: Tye A.M. , Kessler H. , Ambrose K. , Williams J.D.O. , Tragheim D. , Scheib A. , Raines M. , Kuras O.
Published: October 2010

An integrated geological, geophysical and remote sensing survey was undertaken as part of the construction of a high‐resolution 3D model of the shallow subsurface geology of part of the Trent Valley in Nottinghamshire, UK. The 3D model was created using the GSI3D software package and the geophysical techniques used included ground‐penetrating radar (GPR), electrical resistivity tomography (ERT) and automated resistivity profiling. In addition, the remote sensing techniques of light detection and ranging (LIDAR) and airborne thematic mapping (ATM) were used. The objective of the study was to assess the contribution of these techniques to improve the geological mapping and interpretation of terrace deposits and other geological features. The study site had an area of ~2 km2and consisted of a Triassic mudstone escarpment, overlain first by a sand and gravel river terrace that extended to the modern floodplain of the River Trent. Automated resistivity profiling mapping proved to be the central tool in identifying and positioning geological features at a greater resolution than would be obtained through traditional geological mapping and borehole observation. These features included i) a buried cliff delineating the south‐eastern limits of the incised Trent valley, ii) siltstone beds within the Gunthorpe Member of the Mercia Mudstone Group and iii) the variability of the sediments within the river terrace. A long ERT transect across the site successfully imaged the buried cliff and outcropping siltstone beds on the escarpment. Combined ERT and GPR transects revealed the depth of the sand and gravel deposits (Holme Pierrepont sands and gravels), whilst the GPR provided information about the depositional environment. Remote sensing using light detection and ranging proved essential in the original geological survey because it confirmed the absence of a second river terrace that had been previously thought to exist. This case study demonstrates the importance of combining geophysical techniques with traditional geological survey and borehole analysis, in order to create high‐resolution 3D geological models, which are increasingly being used as a platform to understand and solve environmental problems.
Phenological Development and Production Potentials of Tomato under Polyhouse Climate
Authors: Parvej MR , Khan MAH , Awal MA
Published: October 2010

An experiment was conducted in a covered polyhouse along with an open field (control) aside the Field Laboratory of the Department of Crop Botany, Bangladesh Agricultural University, Mymensingh during the period from December 2007 to April 2008 to compare the phenological development and production potentials of two tomato varieties viz. BARI Tomato-3 and Ratan under polyhouse and open field conditions. Photosynthetically active radiation inside the polyhouse was reduced by about 40% compared to the outside (i.e. open field) while air and soil temperatures were always remained higher. From December to February the mid day air temperature under polyhouse and open field varied from 31.8 to 39.1ºC and 23.3 to 31.1ºC, respectively indicating about 8ºC higher air temperature inside polyhouse and during that time the average air temperature inside polyhouse was about 28ºC which was optimum for the growth and development of tomato plants. Relative humidity had opposite trends with that of air temperature i.e. it was lower inside the polyhouse as compared to open field. The above microclimatic variabilities inside polyhouse favoured the growth and development of tomato plant through increased plant height, number of branches/plant, rate of leaf area expansion and leaf area index over the plants grown in open field. Flowering, fruit setting and fruit maturity in polyhouse plants were advanced by about 3, 4 and 5 days, respectively compared to the crop raised in open field condition. Polyhoused plants had higher number of flower clusters/plant, flowers/cluster, flowers/plant, fruit clusters/plant, fruits/cluster and fruits/plant, and fruit length, fruit diameter, individual fruit weight, fruit weight/plant and fruit yield over open field condition. The fruit yield obtained from the polyhouse was 81 t/ha against 57 t/ha from the open field. Key words: Phenological development; polyhouse climate; production potentials; tomato. DOI: 10.4038/jas.v5i1.2329 Journal of Agricultural Sciences Vol.5(1) 2010 pp.19-31
No Requirement of Trans Presentations of IL-15 for Human CD8 T Cell Proliferation
Authors: Ota Naruhisa , Takase Mitsuyo , Uchiyama Hidemi , Olsen Shaun K. , Kanagawa Osami
Published: October 2010

The trans presentation of IL-15 by cells expressing the specific high-affinity receptor α-chain (IL-15Rα) to cells expressing the signaling receptor β-chain and γ-chain is essential for the generation and maintenance of CD8 memory T cells, NK cells, and NKT cells in an in vivo mouse system. We have also demonstrated in vitro that cell-surface IL-15Rα on cells expressing all the receptor components present IL-15 to receptor β-chain/γ-chain coexpressed on the same cell surface (cis presentation). However, although mouse CD8 T cells express all the IL-15R components, they show no evidence of cis presentation. In this study, we demonstrate that increased expression of mouse IL-15Rα in mouse CD8 T cells by retrovirus-mediated gene transfer changes the ability of the T cell to use cis presentation on the cell surface, indicating that cis presentation requires high expression of mouse IL-15Rα on the cell surface. Using cell lines expressing human or mouse receptors, we demonstrate that cis presentation occurs more efficiently in the human receptor–ligand combination than in that of the mouse system. Moreover, we found that primary human CD8 T cells do not require trans presentation of human IL-15 in vitro. These findings raise the possibility that the maintenance and generation of memory CD8 T cells are achieved via distinct mechanisms in humans and mice. Therefore, careful study of the human immune system, rather than extrapolation from the murine model, is necessary to achieve more complete understanding of memory CD8 T cell development in humans.
β7 Integrin Deficiency Suppresses B Cell Homing and Attenuates Chronic Ileitis in SAMP1/YitFc Mice
Authors: Gorfu Gezahegn , Rivera-Nieves Jesus , Hoang Sharon , Abbott Derek W. , Arbenz-Smith Keely , Azar David W. , Pizarro Theresa T. , Cominelli Fabio , McDuffie Marcia , Ley Klaus
Published: October 2010

Lymphocyte recruitment to intestinal tissues depends on β7 integrins. In this study, we studied disease severity and lymphocyte recruitment into the small intestine in SAMP1/YitFc mice, which develop chronic ileitis with similarity to human Crohn’s disease. To assess the role of β7 integrins in chronic ileitis, we generated SAMP1/YitFc lacking β7 integrins (SAMP1/YitFc Itgb7−/−) using a congenic strain developed via marker-assisted selection. We analyzed ileal inflammation in SAMP1/YitFc and SAMP1/YitFc Itgb7−/− mice by histopathology and the distribution of T and B lymphocytes in the mesenteric lymph nodes (MLNs) by flow cytometry. Short-term (18 h) adoptive transfer experiments were used to study the in vivo homing capacity of T and B lymphocytes. In both young (<20 wk) and old (20–50 wk) SAMP1/YitFc Itgb7−/− mice, ileitis was reduced by 30–50% compared with SAMP1/YitFc mice. SAMP1/YitFc Itgb7−/− mice showed a dramatic 67% reduction in the size of their MLNs, which was caused by a 85% reduction in lymphocyte numbers and reduced short-term B cell homing. Flow cytometric analysis revealed a highly significant decrease in the percentage of B cells in MLNs of SAMP1/YitFc Itgb7−/− mice. Cotransfer of SAMP1/YitFc MLN B cells but not SAMP1/YitFc Itgb7−/− MLN B cells along with CD4+ T cells resulted in exacerbated ileitis severity in SCID mice. Our findings suggest that β7 integrins play an essential role in spontaneous chronic ileitis in vivo by promoting homing of disease-exacerbating B cells to MLNs and other intestinal tissues.
Substance P Upregulates Cyclooxygenase-2 and Prostaglandin E Metabolite by Activating ERK1/2 and NF-κB in a Mouse Model of Burn-Induced Remote Acute Lung Injury
Authors: Sio Selena W. S. , Ang Seah Fang , Lu Jia , Moochhala Shabbir , Bhatia Madhav
Published: October 2010

Acute lung injury (ALI) is a major cause of mortality in burn patients, even without direct inhalational injury. Identification of early mediators that instigate ALI after burn and of the molecular mechanisms by which they work are of high importance but remain poorly understood. We previously reported that an endogenous neuropeptide, substance P (SP), via binding neurokinin-1 receptor (NK1R), heightens remote ALI early after severe local burn. In this study, we examined the downstream signaling pathway following SP-NK1R coupling that leads to remote ALI after burn. A 30% total body surface area full-thickness burn was induced in male BALB/c wild-type (WT) mice, preprotachykinin-A (PPT-A) gene-deficient mice, which encode for SP, and PPT-A−/− mice challenged with exogenous SP. Local burn injury induced excessive SP-NK1R signaling, which activated ERK1/2 and NF-κB, leading to significant upregulation of cyclooxygenase (COX)-2, PGE metabolite, and remote ALI. Notably, lung COX-2 levels were abrogated in burn-injured WT mice by L703606, PD98059, and Bay 11-7082, which are specific NK1R, MEK-1, and NF-κB antagonists, respectively. Additionally, burn-injured PPT-A−/− mice showed suppressed lung COX-2 levels, whereas PPT-A−/− mice injected with SP showed augmented COX-2 levels postburn, and administration of PD98059 and Bay 11-7082 to burn-injured PPT-A−/− mice injected with SP abolished the COX-2 levels. Furthermore, treatment with parecoxib, a selective COX-2 inhibitor, attenuated proinflammatory cytokines, chemokines, and ALI in burn-injured WT mice and PPT-A−/− mice injected with SP. To our knowledge, we show for the first time that SP-NK1R signaling markedly elevates COX-2 activity via ERK1/2 and NF-κB, leading to remote ALI after burn.
Blockade of Programmed Death-1 Pathway Rescues the Effector Function of Tumor-Infiltrating T Cells and Enhances the Antitumor Efficacy of Lentivector Immunization
Authors: Zhou Qifeng , Xiao Haiyan , Liu Yanjun , Peng Yibing , Hong Yuan , Yagita Hideo , Chandler Phillip , Munn David H. , Mellor Andrew , Fu Ning , He Yukai
Published: October 2010

Despite intensive effort, the antitumor efficacy of tumor vaccines remains limited in treating established tumors regardless of the potent systemic tumor-specific immune response and the increases of tumor infiltration of T effector cells. In the current study, we demonstrated that although lentivector (lv) immunization markedly increased Ag-dependent tumor infiltration of CD8 and CD4 T cells and generated Ag-specific antitumor effect, it simultaneously increased the absolute number of myeloid-derived suppressor cells and regulatory T cells in the tumor lesions. In addition, lv immunization induced expression of programmed death-ligand 1 in the tumor lesions. Furthermore, the tumor-infiltrating CD8 T cells expressed high levels of programmed death-1 and were partially dysfunctional, producing lower amounts of effector cytokines and possessing a reduced cytotoxicity. Together, these immune-suppression mechanisms in the tumor microenvironment pose a major obstacle to effective tumor immunotherapy and may explain the limited antitumor efficacy of lv immunization. The loss of effector function in the tumor microenvironment is reversible, and the effector function of CD8 T cells in the tumor could be partially rescued by blocking programmed death-1 and programmed death-ligand 1 pathway in vitro and in vivo, resulting in enhanced antitumor efficacy of lv immunization. These data suggest that immunization alone may exacerbate immune suppression in the tumor lesions and that methods to improve the tumor microenvironment and to rescue the effector functions of tumor-infiltrating T cells should be incorporated into immunization strategies to achieve enhanced antitumor efficacy.
Neutropenia Enhances Lung Dendritic Cell Recruitment in Response to Aspergillus via a Cytokine-to-Chemokine Amplification Loop
Authors: Park Stacy J. , Burdick Marie D. , Brix William K. , Stoler Mark H. , Askew David S. , Strieter Robert M. , Mehrad Borna
Published: October 2010

Current understanding of specific defense mechanisms in the context of neutropenic infections is limited. It has previously been reported that invasive aspergillosis, a prototypic opportunistic infection in neutropenic hosts, is associated with marked accumulation of inflammatory dendritic cells (DCs) in the lungs. Given recent data indicating that neutrophils can modulate immune responses independent of their direct microbial killing, we hypothesized that neutropenia impacts the host response to Aspergillus by determining the migration and phenotype of lung DCs. Inflammatory DCs, but not other DC subsets, were found to accumulate in the lungs of neutropenic hosts challenged with killed or live-attenuated Aspergillus as compared with nonneutropenic hosts, indicating that the accumulation was independent of neutrophil microbicidal activity. The mechanism of this accumulation in neutropenic hosts was found to be augmented influx of DCs, or their precursors, from the blood to the lungs. This effect was attributable to greatly elevated lung TNF expression in neutropenic as compared with nonneutropenic animals. This resulted in greater lung expression of the chemokine ligands CCL2 and CCL20, which, in turn, mediated enhanced recruitment of TNF-producing inflammatory DCs, resulting in a positive feedback cycle. Finally, in the context of neutropenic invasive aspergillosis, depletion of DCs resulted in impaired fungal clearance, indicating that this mechanism is protective for the host. These observations identify what we believe is a novel defense mechanism in invasive aspergillosis that is the result of alterations in DC traffic and phenotype and is specific to neutropenic hosts.
Possible Link between Metabolic Syndrome and Chronic Kidney Disease in the Development of Cardiovascular Disease
Authors: Nitta Kosaku
Published: October 2010

Metabolic syndrome (MetS) is a clinical syndrome that consists of visceral obesity, dyslipidemia, hypertension, and impaired insulin sensitivity. Although individual components of MetS have been implicated in the development of chronic kidney disease (CKD), few studies have examined the effect of combinations of the components of MetS on the development of CKD and cardiovascular disease (CVD). The prevalence of MetS is increasing worldwide in both developing and developed countries, and early detection and treatment of MetS would be a cost-effective strategy for preventing the development of CKD. Visceral obesity and insulin resistance are two important features of MetS that may be associated with renal damage. Lifestyle modifications, including caloric restriction and exercise, are necessary to treat MetS. Initial antihypertensive therapy should consist of an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker. An improved understanding of the mechanism responsible for the association between MetS and renal damage should be helpful in determining the treatment regimens directed at cardiovascular and renal protection.
MTHFR A1298C polymorphism and idiopathic male infertility
Authors: Singh K , Singh SK , Raman R
Published: October 2010

Background:

DNA methylation is an important epigenetic feature of DNA that plays a pivotal role in gene expression regulation during spermatogenesis. The enzyme methylenetetrahydrofolate reductase (MTHFR) catalyses the formation of folate intermediates that are vital for DNA synthesis and methylation reactions. C677T and A1298C variants of MTHFR result in reduced plasma folate and increase the susceptibility to various multifactorial disorders. We have already shown that homozygosity for 677 (C ®T) mutation in the MTHFR gene, is a risk factor for idiopathic male infertility in an Indian population. Aim: Recently, we showed that homozygosity for the 677(C;T) mutation in the MTHFR gene is a risk factor for idiopathic male infertility and now we aim to assess whether the A1298C mutation in the same gene is an additional risk factor for idiopathic male infertility in an Indian population.

Setting and Designs:

In a case-control study 151 idiopathic male infertile patients and 140 healthy fertile control individuals were recruited from the University hospital and infertility clinics in Varanasi city, India.

Materials and Methods:

Genotyping for A1298C change of the MTHFR gene was done by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

Statistical Analysis:

Allele frequencies were calculated using Fisher's exact test. Odds ratio was calculated as the measure of the association between the MTHFR genotype and idiopathic male infertility.

Results:

The homozygous (C/C) A1298C polymorphism of the MTHFR gene was present at a statistically high significance in idiopathic azoospermic infertile men (OR=3.4494, CI: 1.0092 to 11.7899, P<0.05).

Conclusion:

The MTHFR 1298CC genotype is an additional genetic risk factor for idiopathic male infertility in an Indian population.
Selective estrogen receptor modulators promising for cardiac syndrome X
Authors: Chen YX , Luo NS , Lin YQ , Yuan WL , Xie SL , Nie RQ , Wang JF
Published: October 2010

Cardiac syndrome X (CSX) is defined as a typical anginal-like chest pain with a transient ischemic electrocardiogram, but without abnormal coronary angiography. It is usually accepted that endothelial dysfunction, inflammation, oxidative stress and estrogen deficiency are the main reasons of CSX. There are some methods to treat CSX including statins, b blocker, angiotensin converting enzyme inhibitors, nitrates, estrogen, and so on. The estrogen replacement therapy (ERT), in particular, has been reported by many researchers to significantly reduce the frequency of chest pain after administration of estrogen, which has been explained as estrogen acting on its receptor to improve the endothelial function. However, it has been suggested that ERT must not be used for coronary heart disease due to its adverse effects. However, some selective estrogen receptor modulators (SERMs) can inhibit inflammatory response as well as oxidative stress, and improve the endothelial function, to reduce the occurrence of chest pain. Here, we hypothesize that SERMs may be the beneficial selection for patients with CSX.
Efficacy of anti-scorpion venom serum over prazosin in the management of severe scorpion envenomation
Authors: Natu VS , Kamerkar SB , Geeta K , Vidya K , Natu V , Sane S , Kushte R , Thatte S , Uchil DA , Rege NN , Bapat RD
Published: October 2010

Background:

Scorpion venoms cause a massive release of neurotransmitters. Either anti-scorpion venom serum (AScVS) or prazosin has been used in the management of severe scorpion envenomation.

Aims:

To compare the time taken for clinical recovery by patients with severe scorpion envenomation after AScVS therapy with that following prazosin therapy.

Settings and Design:

A prospective, open-labeled clinical trial was undertaken to compare the effects of the AScVS and/or prazosin on clinical recovery in scorpion-stung patients.

Materials and Methods:

Eighty-one patients from rural districts of Maharashtra presenting with severe scorpion envenomation were assigned to three treatment groups (AScVS: n = 28; prazosin: n = 25; AScVS + prazosin: n = 28). Severity of scorpion envenomation was graded using a proposed composite clinical scoring system to assess the therapeutic efficacy. AScVS was administered as an intravenous slow bolus, ranging from 40 to 100 ml, depending on the severity of envenomation. Prazosin was given as 1 mg every 3 h.

Statistical Analysis Used:

The non-parametric "Kruskal-Wallis" test was used in the statistical analysis and a P-value of 0.05 was considered significant.

Results:

Mean composite scores of patients from the three groups at the time of admission were comparable. Complete clinical recovery was noted in 4.14 ± 1.6 h and 19.28 ± 5.03 h in the subjects who were administered AScVS and prazosin, respectively (P < 0.001). There was no incidence of anaphylactic reaction to AScVS.

Conclusions:

Intravenous slow bolus of AScVS given based on the clinical severity of envenomation leads to early recovery than prazosin alone and is well tolerated.
Multiple ring-enhancing lesions of the brain
Authors: Garg RK , Sinha MK
Published: October 2010

Multiple ring-enhancing lesions of the brain are one of the most commonly encountered abnormalities on neuroimaging. These can be caused by a variety of infectious, neoplastic, inflammatory or vascular diseases. Distinguishing non-neoplastic causes from neoplastic lesions is extremely important because a misdiagnosis can lead to unwarranted neurosurgery and exposure to toxic chemotherapy or potentially harmful brain irradiation. Diligent clinical evaluation and a battery of tests are required for making a definitive diagnosis. Newer advanced diagnostic techniques, such as diffusion-weighted magnetic resonance imaging (MRI), perfusion-weighted MRI, magnetic resonance spectroscopy, single-photon emission tomography and positron emission tomography may help in establishing the etiology. However, early brain biopsy is often needed because several of these diseases are potentially life-threatening.
Evaluation of clinical skills for first-year surgical residents using orientation programme and objective structured clinical evaluation as a tool of assessment
Authors: Pandya JS , Bhagwat SM , Kini SL
Published: October 2010

Background:

Postgraduate specialities require a combination of knowledge and clinical skills. The internship year is less structured. Clinical and practical skills that are picked up during training are not well regulated and the impact is not assessed. In this study, we assessed knowledge and skills using objective structured clinical examination (OSCE).

Aim:

To evaluate the clinical skills of new first-year surgical residents using orientation programme and OSCE as a tool for assessment.

Settings and Design:

Observational study.

Materials and Methods:

Twenty new first-year surgical residents (10 each in 2008 and 2009) participated in a detailed structured orientation programme conducted over a period of 7 days. Clinically important topics and skills expected at this level (e.g., suturing, wound care etc.) were covered. The programme was preceded by an OSCE to test pre-programme knowledge (the "pre-test"). The questions were validated by senior department staff. A post-programme OSCE (the "post-test") helped to evaluate the change in clinical skill level brought about by the orientation programme.

Statistical Analysis:

Wilcoxson matched-pairs signed-ranks test.

Results:

Passing performance was achieved by all participants in both pre- and post-tests. Following the orientation programme, significant improvement was seen in tasks testing the psychomotor and cognitive domains. (P= 0.0001 andP= 0.0401, respectively). Overall reliability of the OSCE was found to be 0.7026 (Cronbach's coefficient alpha).

Conclusions:

This study highlighted the lacunae in current internship training, especially for skill-based tasks. There is a need for universal inclusion of structured orientation programmes in the training of first-year residents. OSCE is a reliable, valid and effective method for the assessment of clinical skills.
Alpha‐Synuclein Stimulation of Astrocytes: Potential Role for Neuroinflammation and Neuroprotection
Authors: Lee He-Jin , Kim Changyoun , Lee Seung-Jae
Published: October 2010

Selective loss of neurons, abnormal protein deposition and neuroinflammation are the common pathological features of neurodegenerative diseases, and these features are closely related to one another. In Parkinson′s disease, abnormal aggregation and deposition of α‐synuclein is known as a critical event in pathogenesis of the disease, as well as in other related neurodegenerative disorders, such as dementia with Lewy bodies and multiple system atrophy. Increasing evidence suggests that α‐synuclein aggregates can activate glial cells to induce neuroinflammation. However, how an inflammatory microenvironment is established and maintained by this protein remains unknown. Findings from our recent study suggest that neuronal α‐synuclein can be directly transferred to astrocytes through sequential exocytosis and endocytosis and induce inflammatory responses from astrocytes. Here we discuss potential roles of astrocytes in a cascade of events leading to α‐synuclein‐induced neuroinflammation.
Carnitine Deficiency and Oxidative Stress Provoke Cardiotoxicity in an Ifosfamide‐Induced Fanconi Syndrome Rat Model
Authors: Sayed-Ahmed Mohamed M. , Darweesh Amal Q. , Fatani Amal J.
Published: October 2010

In addition to hemorrhagic cystitis, Fanconi Syndrome is a serious clinical side effect during ifosfamide (IFO) therapy. Fanconi syndrome is a generalized dysfunction of the proximal tubule which is characterized by excessive urinary excretion of glucose, phosphate, bicarbonate, amino acids and other solutes excreted by this segment of the nephron including L‐carnitine. Carnitine is essential cofactor for β‐oxidation of long‐chain fatty acids in the myocardium. IFO therapy is associated with increased urinary carnitine excretion with subsequent secondary deficiency of the molecule. Cardiac abnormalities in IFO‐treated cancer patients were reported as isolated clinical cases. This study examined whether carnitine deficiency and oxidative stress, secondary to Fanconi Syndrome, provoke IFO‐induced cardiomyopathy as well as exploring if carnitine supplementation using Propionyl‐L‐carnitine (PLC) could offer protection against this toxicity. In the current study, an animal model of carnitine deficiency was developed in rats by D‐carnitine‐mildronate treatment Adult male Wistar albino rats were assigned to one of six treatment groups: the first three groups were injected intraperitoneally with normal saline, D‐carnitine (DC, 250 mg/kg/day) combined with mildronate (MD, 200 mg/kg/day) and PLC (250 mg/kg/day), respectively, for 10 successive days. The 4th, 5th and 6th groups were injected with the same doses of normal saline, DC‐MD and PLC, respectively for 5 successive days before and 5 days concomitant with IFO (50 mg/kg/day). IFO significantly increased serum creatinine, blood urea nitrogen (BUN), urinary carnitine excretion and clearance, creatine phosphokinase isoenzyme (CK‐MB), lactate dehydrogenase (LDH), intramitochondrial acetyl‐CoA/CoA‐SH and thiobarbituric acid reactive substances (TBARS) in cardiac tissues and significantly decreased adenosine triphosphate (ATP) and total carnitine and reduced glutathione (GSH) content in cardiac tissues. In carnitine‐depleted rats, IFO induced dramatic increase in serum creatinine, BUN, CK‐MB, LDH, carnitine clearance and intramitochondrial acetyl‐CoA/CoA‐SH, as well as progressive reduction in total carnitine and ATP in cardiac tissues. Interestingly, PLC supplementation completely reversed the biochemical changes‐induced by IFO to the control values. In conclusion, data from the present study suggest that: Carnitine deficiency and oxidative stress, secondary to Fanconi Syndrome, constitute risk factors and should be viewed as mechanisms during development of IFO‐induced cardiotoxicity. Carnitine supplementation, using PLC, prevents the development of IFO‐induced cardiotoxicity through antioxidant signalling and improving mitochondrial function.
Age Associated Oxidative Damage in Lymphocytes
Authors: Gautam Nandeslu , Das Subhasis , Mahapatra Santanu Kar , Chakraborty Subhankari Prasad , Kundu Pratip Kumar , Roy Somenath
Published: October 2010

Lymphocytes are an important immunological cell and have been played a significant role in acquired immune system; hence, may play in pivotal role in immunosenescence. Oxidative stress has been reported to increase in elderly subjects, possibly arising from an uncontrolled production of free radicals with aging and decreased antioxidant defenses. This study was aimed to evaluate the level of lipid‐protein damage and antioxidant status in lymphocytes of healthy individuals to correlate between oxidative damage with the aging process. Twenty healthy individuals of each age group (11–20; 21–30; 31–40; 41–50; and 51–60 years) were selected randomly. Blood samples were drawn by medical practitioner and lymphocytes were isolated from blood samples. Malondialdehyde (MDA), protein carbonyls (PC) level were evaluated to determine the lipid and protein damage in lymphocytes. Superoxide dismutase (SOD), catalase (CAT), glutathione and glutathione dependent enzymes were estimated to evaluate the antioxidant status in the lymphocytes. Increased MDA and PC levels strongly support the increased oxidative damage in elderly subject than young subjects. The results indicated that, balance of oxidant and antioxidant systems in lymphocytes shifts in favor of accelerated oxidative damage during aging. Thus oxidative stress in lymphocytes may particular interest in aging and may play important role in immunosenescence.
Deleterious Effects of Reactive Metabolites
Authors: Attia Sabry M.
Published: October 2010

A number of drugs have been withdrawn from the market or severely restricted in their use because of unexpected toxicities that become apparent only after the launch of new drug entities. Circumstantial evidence suggests that, in most cases, reactive metabolites are responsible for these unexpected toxicities. In this review, a general overview of the types of reactive metabolites and the consequences of their formation are presented. The current approaches to evaluate bioactivation potential of new compounds with particular emphasis on the advantages and limitation of these procedures will be discussed. Reasonable reasons for the excellent safety record of certain drugs susceptible to bioactivation will also be explored and should provide valuable guidance in the use of reactive‐metabolite assessments when nominating drug candidates for development. This will, in turn, help us to design and bring safer drugs to the market.
Group Processes and EFL Learners' Motivation: A Study of Group Dynamics in EFL Classrooms
Authors: CHANG LILIAN YA‐HUI
Published: October 2010

This study explores how group processes, such as group cohesiveness and group norms, influence an individual EFL learner's motivation. The uniqueness of this research lies in shifting the focus from an analysis of the individual's experience being seen as apart from the group to considering the individual's experience in relation to the social interactions within the group. Questionnaires were administered to 152 Taiwanese university students from the English Department of a university in Taiwan. The results from the questionnaires show that there was a slight to moderate correlation between group processes (group cohesiveness and group norms) and students' level of motivation (self‐efficacy and autonomy). A dozen students who participated in this study were asked to share more information in semi‐structured in‐depth interviews. During those interviews, several students commented that their learner class group was indeed important to their learning, as associating with more motivated classmates and classmates with whom they get along does positively influence their own motivation. On the other hand, being in a class group of stolid learners who are unresponsive and show little interest or concern for each other could de‐motivate an otherwise motivated learner.
Effects of Dynamic Corrective Feedback on ESL Writing Accuracy
Authors: HARTSHORN K. JAMES , EVANS NORMAN W. , MERRILL PAUL F. , SUDWEEKS RICHARD R. , STRONG‐KRAUSE DIANE , ANDERSON NEIL J.
Published: October 2010

Though recent research has shown that written corrective feedback (WCF) may improve aspects of writing accuracy in some English as a second language (ESL) contexts, many teachers continue to be confused about the practical steps they should utilize to help their students improve their writing. Moreover, some have raised concerns as to whether commonly used approaches to ESL writing pedagogy and grammar instruction are effective in helping students improve their linguistic accuracy. This article describes an instructional strategy we developed for improving students' accuracy based on insights gleaned from practice, research, and theory. We refer to this instructional methodology as dynamic WCF. The article also discusses a test of the methodology's efficacy that compared the performance of two groups of students, one using a conventional process approach to writing instruction and the other using the dynamic WCF approach. Test results demonstrated that although rhetorical competence, writing fluency, and writing complexity were largely unaffected by the dynamic WCF pedagogy, significant improvement was observed for writing accuracy.
Independent vs. Integrated Writing Tasks: A Comparison of Task Representation
Authors: PLAKANS LIA
Published: October 2010

TESOL Quarterlyinvites readers to submit short reports and updates on their work. These summaries may address any areas of interest toQuarterlyreaders.
Should Vocabulary Instruction Be Integrated or Isolated?
Authors: FILE KIERAN ANDREW , ADAMS REBECCA
Published: October 2010

This study compares integrated and isolated form‐focused instruction for vocabulary development in an English as a second language (ESL) reading lesson. Two classes of ESL learners (N = 20) from a university preparation academic English course were involved in the study. Each class did two reading treatments in which they read an article and studied vocabulary from that article. In one of the treatments participants were taught the words in isolation prior to reading the article, and in the other the vocabulary instruction was integrated with reading the article. Paribakht and Wesche's (1997) vocabulary knowledge scale was used as the instrument to measure learning and retention gains for words taught in isolated instruction, in integrated instruction, and words acquired incidentally. Statistical analysis showed both types of instruction led to more learning and retention of vocabulary knowledge than incidental exposure alone. Although retention rates were similar for isolated and integrated instruction, there was a trend for isolated instruction to lead to higher rates of learning.
The potential to narrow uncertainty in projections of stratospheric ozone over the 21st century
Authors: Charlton-Perez A. J. , Hawkins E. , Eyring V. , Cionni I. , Bodeker G. E. , Kinnison D. E. , Akiyoshi H. , Frith S. M. , Garcia R. , Gettelman A. , Lamarque J. F. , Nakamura T. , Pawson S. , Yamashita Y. , Bekki S. , Braesicke P. , Chipperfield M. P. , Dhomse S. , Marchand M. , Mancini E. , Morgenstern O. , Pitari G. , Plummer D. , Pyle J. A. , Rozanov E. , Scinocca J. , Shibata K. , Shepherd T. G. , Tian W. , Waugh D. W.
Published: October 2010

Abstract. Future stratospheric ozone concentrations will be determined both by changes in the concentration of ozone depleting substances (ODSs) and by changes in stratospheric and tropospheric climate, including those caused by changes in anthropogenic greenhouse gases (GHGs). Since future economic development pathways and resultant emissions of GHGs are uncertain, anthropogenic climate change could be a significant source of uncertainty for future projections of stratospheric ozone. In this pilot study, using an "ensemble of opportunity" of chemistry-climate model (CCM) simulations, the contribution of scenario uncertainty from different plausible emissions pathways for ODSs and GHGs to future ozone projections is quantified relative to the contribution from model uncertainty and internal variability of the chemistry-climate system. For both the global, annual mean ozone concentration and for ozone in specific geographical regions, differences between CCMs are the dominant source of uncertainty for the first two-thirds of the 21st century, up-to and after the time when ozone concentrations return to 1980 values. In the last third of the 21st century, dependent upon the set of greenhouse gas scenarios used, scenario uncertainty can be the dominant contributor. This result suggests that investment in chemistry-climate modelling is likely to continue to refine projections of stratospheric ozone and estimates of the return of stratospheric ozone concentrations to pre-1980 levels.
Glycine in aerosol water droplets: a critical assessment of Köhler theory by predicting surface tension from molecular dynamics simulations
Authors: Li X. , Hede T. , Tu Y. , Leck C. , Ågren H.
Published: October 2010

Abstract. Aerosol particles in the atmosphere are important participants in the formation of cloud droplets and have significant impact on cloud albedo and global climate. According to the Köhler theory which describes the nucleation and the equilibrium growth of cloud droplets, the surface tension of an aerosol droplet is one of the most important factors that determine the critical supersaturation of droplet activation. In this paper, with specific interest to remote marine aerosol, we predict the surface tension of aerosol droplets by performing molecular dynamics simulations on two model systems; the pure water droplets and glycine in water droplets. The curvature dependence of the surface tension is interpolated by a quadratic polynomial over the nano-sized droplets and the limiting case of a planar interface, so that the so-called Aitken mode particles which are critical for droplet formation could be covered and the Köhler equation could be improved by incorporating surface tension corrections.