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Synthesis and Characterization of Ultrafine Grained 304 Stainless Steel through Machining  [PDF]
V. Senthilkumar, K. Lenin
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2011, DOI: 10.4236/jmmce.2011.105034
Abstract: The microstructures of 304 stainless steel chips created by plane strain machining at ambient temperature have been analyzed using scanning electron microscopy (SEM) and the crystallite size of the ultrafine chips were analyzed using X-Ray Diffraction Analysis. The strain imposed in the chips was varied by changing the tool rake angle. An attempt is made in the present investigation to correlate the plastic strain, strain rate with the grain size of the stainless steel.
Historias nacionales, historias de los trabajadores y el problema de la democracia en la obra de Charles Bergquist
Florez Lenin
Anuario Colombiano de Historia Social y de la Cultura , 1992,
Abstract: La obra de Bergquist es examinada a la luz de los problemas teóricos y metodológicos expuestos por el autor. Se contrastan aspectos específicos, utilizando como punto de referencia conceptos de otros investigadores que han estudiado la historia de los trabajadores colombianos.
La legislación del servicio público de radiodifusión en México: un letargo pendiente
Lenin Martell
Espacios Públicos , 2007,
Abstract: La legislación del servicio público de radiodifusión en México: un letargo pendiente
Sighting frequency and relative abundance of bottlenose dolphins (Tursiops truncatus) along the northeast coast of Margarita Island and Los Frailes Archipelago, Venezuela
Oviedo,Lenin; Silva,Noemi;
Revista de Biología Tropical , 2005,
Abstract: the study of local cetaceans in venezuela has a very recent history, and few efforts have been made in the assessment of coastal populations based on field research. the occurrence of whales and dolphins along the northeast coast of venezuela has been documented through sightings and stranding records. given the underwater topographical features and the influence of upwelling processes, this area is considered a very productive coastal ecosystem. our objective was to establish the sighting frequency and relative abundance of bottlenose dolphins in the area. sighting records were gathered on bottlenose dolphins and other cetacean species occurring along the northeast coast of margarita island and los frailes archipelago through direct observation during land-based (6 surveys, 48 hours of observation) and boat-based surveys (24 surveys, 121 hours of observation, 1295 km covered). a sighting frequency was calculated using two methodologies and then compared, considering: 1) a mean effective observation time (4.27 hours), and 2) distance covered with cetacean sightings (1108 km). a third method is proposed relating a mean effective distance covered with cetacean sightings and expressed as a percentage. the abundance index was calculated using the mean effective observation time. the sighting frequency of tursiops truncatus in the study area was 3 - 4 sightings per day of 4.27 observation hours, or by 185 kilometers covered. the relative abundance was calculated as 35 dolphins in the study area, so a total population of less than 60 dolphins could inhabit the proposed range. tursiops truncatus is the dominant species in the northeast coast of margarita island and los frailes archipelago with 70% of all the sightings, so this locality could be termed as the distribution range of a possible local population of bottlenose dolphins. rev. biol. trop. 53(3-4): 595-600. epub 2005 oct 3.
Ramp position for intubating morbidly obese parturient: What′s new?
Thangaswamy Chitra,Elakkumanan Lenin
Indian Journal of Anaesthesia , 2011,
Abstract:
Sighting frequency and relative abundance of bottlenose dolphins (Tursiops truncatus) along the northeast coast of Margarita Island and Los Frailes Archipelago, Venezuela
Lenin Oviedo,Noemi Silva
Revista de Biología Tropical , 2005,
Abstract: The study of local cetaceans in Venezuela has a very recent history, and few efforts have been made in the assessment of coastal populations based on field research. The occurrence of whales and dolphins along the northeast coast of Venezuela has been documented through sightings and stranding records. Given the underwater topographical features and the influence of upwelling processes, this area is considered a very productive coastal ecosystem. Our objective was to establish the sighting frequency and relative abundance of bottlenose dolphins in the area. Sighting records were gathered on bottlenose dolphins and other cetacean species occurring along the northeast coast of Margarita Island and Los Frailes Archipelago through direct observation during land-based (6 surveys, 48 hours of observation) and boat-based surveys (24 surveys, 121 hours of observation, 1295 km covered). A sighting frequency was calculated using two methodologies and then compared, considering: 1) a mean effective observation time (4.27 hours), and 2) distance covered with cetacean sightings (1108 km). A third method is proposed relating a mean effective distance covered with cetacean sightings and expressed as a percentage. The abundance index was calculated using the mean effective observation time. The sighting frequency of Tursiops truncatus in the study area was 3 - 4 sightings per day of 4.27 observation hours, or by 185 kilometers covered. The relative abundance was calculated as 35 dolphins in the study area, so a total population of less than 60 dolphins could inhabit the proposed range. Tursiops truncatus is the dominant species in the northeast coast of Margarita Island and Los Frailes Archipelago with 70% of all the sightings, so this locality could be termed as the distribution range of a possible local population of bottlenose dolphins. Rev. Biol. Trop. 53(3-4): 595-600. Epub 2005 Oct 3. El estudio de cetáceos locales en Venezuela tiene una historia bien reciente. Pocos esfuerzos se han hecho para evaluar las poblaciones costeras de estos mamíferos sobre la base de muestreo en campo. La presencia de ballenas y delfines en la costa noreste de Venezuela ha sido documentada a través de avistamiento y en una mayor proporción por medio de registros de varamientos. Esto esta ampliamente relacionado con un ecosistema costanero muy productivo asociado a las características topográficas y los procesos de surgencia. El objetivo de esta contribución es establecer la frecuencia de avistamiento y la abundancia relativa del delfín nariz de botella en el área de estudio. Se colecta
Laclau, Ernesto. La razón populista. Buenos Aires: Fondo de Cultura Económica, 2005. 312 páginas.
Flórez Lenin
Anuario Colombiano de Historia Social y de la Cultura , 2006,
Abstract:
Qué significa la participación ciudadana en la radio hoy en día?
Lenin Martell Gámez
Espacios Públicos , 2006,
Abstract: El presente ensayo discute cómo se configura la participación ciudadana de la radio en México actualmente, en qué consiste, cuáles son los actores sociales que la conforman, cuál ha sido su desarrollo histórico reciente. Para ello, el autor aborda el tema desde una perspectiva hist órico-descriptiva, tomando como referencia la radio comunitaria urbana y la indigenista. El artículo forma parte de una investigación más amplia sobre el servicio público de radio en México en el marco del neoliberalismo.
Astrocytes Prevent Ethanol Induced Apoptosis of Nrf2 Depleted Neurons by Maintaining GSH Homeostasis  [PDF]
Madhusudhanan Narasimhan, Marylatha Rathinam, Dhyanesh Patel, George Henderson, Lenin Mahimainathan
Open Journal of Apoptosis (OJApo) , 2012, DOI: 10.4236/ojapo.2012.12002
Abstract: Glutathione (GSH), a major cellular antioxidant protects cells against oxidative stress injury. Nuclear factor erythroid 2-related factor 2 (NFE2L2/Nrf2) is a redox sensitive master regulator of battery of antioxidant enzymes including those involved in GSH antioxidant machinery. Earlier we reported that ethanol (ETOH) elicits apoptotic death of pri-mary cortical neurons (PCNs) which in partly due to depletion of intracellular GSH levels. Further a recent report from our laboratory illustrated that ETOH exacerbated the dysregulation of GSH and caspase mediated cell death of pure cortical neurons that are compromised in Nrf2 machinery (Narasimhan et al., 2011). In various experimental models of neurodegeneration, neuronal antioxidant defenses mainly GSH has been shown to be supported by astrocytes. We therefore sought to determine whether astrocytes can render protection to neurons against ETOH toxicity, particularly when the function of Nrf2 is compromised in neurons. The experimental model consisted of co-culturing PCAs with Nrf2 downregulated PCNs that were exposed with and without 4 mg/mL ETOH for 24 h. Monochlorobimane (MCB) staining followed by FACS analysis showed that astrocytes blocked ETOH induced GSH decrement in Nrf2-silenced neurons as opposed to exaggerated GSH depletion in Nrf2 downregulated PCNs alone. Similarly, the heightened activa-tion of caspase 3/7 observed in Nrf2-compromised neurons was attenuated when co-cultured with astrocytes as meas-ured by luminescence based caspase Glo assay. Furthermore, annexin-V-FITC staining followed by FACS analysis re-vealed that Nrf2 depleted neurons showed resistance to ETOH induced neuronal apoptosis when co-cultured with as-trocytes. Thus, the current study identifies ETOH induced dysregulation of GSH and associated apoptotic events ob-served in Nrf2-depleted neurons can be blocked by astrocytes. Further our results suggest that this neuroprotective ef-fect of astrocyte despite dysfunctional Nrf2 system in neurons could be compensated by astrocytic GSH supply.
Performance evaluation of a diesel engine fueled with methyl ester of pongamia oil
A. Haiter Lenin, K. Thyagarajan
International Journal of Energy and Environment , 2012,
Abstract: In this study pongamia methyl ester was prepared by transesterification using potassium hydroxide (KOH) as catalyst and was used as fuel in a four stroke, water cooled, single cylinder, direct injection diesel engine. Pongamia methyl ester fuel blends (75% and 100%) were used for conducting the engine performance tests at varying loads (20%, 40%, 60%, 80%, and 100%). Tests were carried out over entire range of engine operation at varying conditions of load. The performance, combustion and emission characteristics were determined. Based on these, the parameters such as brake thermal efficiency, specific fuel consumption, exhaust gas temperature, emissions in exhaust such as CO, CO2, O2, HC and NOx were recorded. The results show that the blend of pongamia oil with diesel fuel can be used as an alternative fuel successfully in a diesel engine without any modification.
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