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Search Results: 1 - 10 of 149155 matches for " Timothy F. Lesser "
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Review of the Surgical Approaches for Peyronie's Disease: Corporeal Plication and Plaque Incision with Grafting
Viet Q. Tran,Dennis H. Kim,Timothy F. Lesser,Sherif R. Aboseif
Advances in Urology , 2008, DOI: 10.1155/2008/263450
Abstract: The understanding and management of Peyronie's disease (PD) has improved but elucidating the exact etiology of the disease has yet to be achieved. In this paper, we review the historical and clinical aspects of PD. We focus on the evolution of surgical management for PD and review recent published articles that compare popular surgical techniques such as plication and plaque incision with vein graft. These two techniques have been reported to be equivalent with respect to patient satisfaction; however, each technique has its own advantages and disadvantages.
Penile Corporeal Reconstruction during Difficult Placement of a Penile Prosthesis
Viet Q. Tran,Timothy F. Lesser,Dennis H. Kim,Sherif R. Aboseif
Advances in Urology , 2008, DOI: 10.1155/2008/370947
Abstract: For some patients with impotence and concomitant severe tunical/corporeal tissue fibrosis, insertion of a penile prosthesis is the only option to restore erectile function. Closing the tunica over an inflatable penile prosthesis in these patients can be challenging. We review our previous study which included 15 patients with severe corporeal or tunical fibrosis who underwent corporeal reconstruction with autologous rectus fascia to allow placement of an inflatable penile prosthesis. At a mean follow-up of 18 months (range 12 to 64), all patients had a prosthesis that was functioning properly without evidence of separation, herniation, or erosion of the graft. Sexual activity resumed at a mean time of 9 weeks (range 8 to 10). There were no adverse events related to the graft or its harvest. Use of rectus fascia graft for coverage of a tunical defect during a difficult penile prosthesis placement is surgically feasible, safe, and efficacious.
A Multifunctional Region of the Shigella Type 3 Effector IpgB1 Is Important for Secretion from Bacteria and Membrane Targeting in Eukaryotic Cells
Sonia C. P. Costa, Cammie F. Lesser
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0093461
Abstract: Type 3 secretion systems are complex nanomachines used by many Gram–negative bacteria to deliver tens of proteins (effectors) directly into host cells. Once delivered into host cells, effectors often target to specific cellular loci where they usurp host cell processes to their advantage. Here, using the yeast model system, we identify the membrane localization domain (MLD) of IpgB1, a stretch of 20 amino acids enriched for hydrophobic residues essential for the targeting of this effector to the plasma membrane. Embedded within these residues are ten that define the IpgB1 chaperone-binding domain for Spa15. As observed with dedicated class IA chaperones that mask hydrophobic MLDs, Spa15, a class IB chaperone, promotes IpgB1 stability by binding this hydrophobic region. However, despite being stable, an IpgB1 allele that lacks the MLD is not recognized as a secreted substrate. Similarly, deletion of the chaperone binding domains of IpgB1 and three additional Spa15-dependent effectors result in alleles that are no longer recognized as secreted substrates despite the presence of intact N-terminal secretion signal sequences. This is in contrast with MLD-containing effectors that bind class IA dedicated chaperones, as deletion of the MLD of these effectors alleviates the chaperone requirement for secretion. These observations indicate that at least for substrates of class IB chaperones, the chaperone-effector complex plays a major role in defining type 3 secreted proteins and highlight how a single region of an effector can play important roles both within prokaryotic and eukaryotic cells.
Climate Change Impacts and Adaptation in Rainfed Farming Systems: A Modeling Framework for Scaling-Out Climate Smart Agriculture in Sub-Saharan Africa  [PDF]
Berhanu F. Alemaw, Timothy Simalenga
American Journal of Climate Change (AJCC) , 2015, DOI: 10.4236/ajcc.2015.44025
Abstract: Improving agricultural water productivity, under rainfed or irrigated conditions, holds significant scope for addressing climate change vulnerability. It also offers adaptation capacity needs as well as water and food security in the southern African region. In this study, evidence for climate change impacts and adaptation strategies in rainfed agricultural systems is explored through modeling predictions of crop yield, soil moisture and excess water for potential harvesting. The study specifically presents the results of climate change impacts under rainfed conditions for maize, sorghum and sunflower using soil-water-crop model simulations, integrated based on daily inputs of rainfall and evapotranspiration disaggregated from GCM scenarios. The research targets a vast farming region dominated by heavy clay soils where rainfed agriculture is a dominant practice. The potential for improving soil water productivity and improved water harvesting have been explored as ways of climate change mitigation and adaptation measures. This can be utilized to explore and design appropriate conservation agriculture and adaptation practices in similar agro-ecological environments, and create opportunities for outscaling for much wider areas. The results of this study can suggest the need for possible policy refinements towards reducing vulnerability and adaptation to climate change in rainfed farming systems.
Modeling of a Contaminant Plume in a Tidally Influenced River Using Domenico’s Equation  [PDF]
Luis E. Lesser-Carrillo
International Journal of Geosciences (IJG) , 2013, DOI: 10.4236/ijg.2013.43048

Currently, the mathematical code Modflow is widely used to simulate groundwater flow in aquifers. Due to the ease which exists today to create mathematical models through Modflow visual Interfaces, it is possible to obtain contamiant transport results which may not have much support, especially when simulating the transport of contaminants with little groundwater flow information. Domenico’s equation is an analytical solution for transport of contaminants in groundwater that can be used when not much groundwater flow information exists. The objective of this study is to model, using Domenico’s equation, a groundwater contaminant plume that discharges into a tidally influenced river. The study area was a wood treatment facility located on the bank of a river which is influenced by tides. Previous studies have found the presence of creosote in the subsurface and the formation of a groundwater plume that apparently discharges into the river. Domenico’s equation was selected to model this site because of the limited piezometric data available at the site to properly simulate the daily hydraulic gradient inversion due to the river tides. Domenico’s equation was successfully used to model this plume and reproduce the field distribution of naphthalene, benzene and 1-methyl-naphthalene. Two sources 40 minland had to be defined to properly simulate the plume behavior. It was determined through modeling that biodegradation plays an important role on the plume’s behavior. These were key issues in the conceptual model understanding of the plume at this site.

13C/12C Isotope Fractionation during Aerobic and Anaerobic Biodegradation of Naphthalene  [PDF]
Luis E. Lesser-Carrillo
International Journal of Geosciences (IJG) , 2014, DOI: 10.4236/ijg.2014.52022

Microcosm experiments were conducted to determine the fractionation of stable carbon isotopes during biodegradation of naphthalene. The microcosms were performed under aerobic conditions, anaerobic (amended with sulfate, amended with nitrate and with no amendments) and sterile controls. The liquid phase was analyzed to determine naphthalene concentration and stable carbon isotope signature. Aerobic microcosm showed that naphthalene degraded aerobically within 60 hours. The δ13C increased from -25.5‰ to -25.1‰ (enrichment of 0.4‰ ± 0.08‰) in a single sample in which 95% of the naphthalene was biodegraded. Anaerobic microcosms show that after 288 days, the microcosms with no amendments, amended with nitrate and amended with sulfate had consumed respectively 30%, 50% and 60% of naphthalene on average, compared to control microcosms. Under the denitrifying conditions, the δ13C of naphthalene increased from -25.2‰ to -23.9‰ (enrichment of 1.3‰ ± 0.3‰) after a 95% of naphthalene biodegradation. For the unamended microcosms, a slight enrichment on δ13C napththalene was detected, from -25.2‰ to -24.5‰ (enrichment of 0.7‰ ± 0.3‰) after a biodegradation of approximately 65% of naphthalene (after 288 days). For sulfate reducing microcosms, no significant changes were detected on the δ13C during naphthalene biodegradation.

Unresolved Issues: Assignments for the North and South
Ian lesser
Revista CIDOB d'Afers Internacionals , 1997,
Abstract: Los Estados del sur del Mediterráneo pertenecen a un “arco de cambio”, y no a un “arco de crisis”, como han pretendido algunos analistas. Desde este prisma, Lesser dibuja cuatro hipótesis sobre el contenido del diálogo y de los problemas de seguridad en esta región. La primera estudia la dimensión de la seguridad interna y las razones de la existencia de Estados “disfuncionales” en el Sur. La segunda resta importancia al fundamentalismo islámico como causa de conflicto; éste estaría más relacionado con preocupaciones tradicionales alentadas desde el extremismo nacionalista, no islamista. En la tercera hipótesis Lesser se ala que los Estados del Sur se hallan inmersos en el proceso de incluir “nuevas geometrías”en sus relaciones de seguridad, ya sea con sus vecinos regionales o con la UE y la OTAN. La cuarta hipótesis coloca la interdependencia entre Europa, Oriente Medio y Eurasia ante los siguientes retos a la seguridad: la proliferación armamentista, el abastecimiento de energía procedente de la cuenca del mar Caspio y su acceso a los mercados occidentales, y los aspectos políticos de la interacción entre Occidente y el mundo musulmán. Estos retos se entrecruzan en el Mediterráneo y lo convierten en la dimensión meridional de la seguridad europea.
Comportamiento de variedades de Chile dulce (capsicum annum) en la región occidental de el Salvador
Lesser Linares
Agronomía Mesoamericana , 2004,
Abstract: Capsicun annum) en la región occidental de El Salvador. Con el objetivo de seleccionar material vegetativo adaptable a las diferentes condiciones agroecológicas de El Salvador, se implementó una investigación de seis variedades de chile dulce. Los ensayos se realizaron en Candelaria de la Frontera, Atiquizaya y Chalchuapa en el a o 2002. El dise o experimental fue de bloques al azar, con cuatro repeticiones y seis tratamientos, conformados por los variedades Nathalie, Comandante, Lido, Tikal, Quetzal y una variedad Criolla. Hubo diferencias significativas al 1 % de probabilidad para las variables de altura de planta, largo, peso, diámetro, numero de frutos y rendimiento, en el combinado de las tres localidades. El material Nathalie, sobresalió en las variables altura de planta (0,49 m), número de frutos (259.500 frutos/ha), y rendimiento (25,11 t/ha), y como consecuencia reportó el mejor ingreso ($ 19.332,80) y la mejor relación beneficio costo (3,31). La duración de anaquel varió entre seis y nueve días con respecto a los diferentes materiales de chile dulce. Los resultados obtenidos podrían crear la base para validar el cultivar Nathalie en las zonas de influencia.
A Functional Genomic Yeast Screen to Identify Pathogenic Bacterial Proteins
Naomi L Slagowski,Roger W Kramer,Monica F Morrison,Joshua LaBaer,Cammie F Lesser
PLOS Pathogens , 2008, DOI: 10.1371/journal.ppat.0040009
Abstract: Many bacterial pathogens promote infection and cause disease by directly injecting into host cells proteins that manipulate eukaryotic cellular processes. Identification of these translocated proteins is essential to understanding pathogenesis. Yet, their identification remains limited. This, in part, is due to their general sequence uniqueness, which confounds homology-based identification by comparative genomic methods. In addition, their absence often does not result in phenotypes in virulence assays limiting functional genetic screens. Translocated proteins have been observed to confer toxic phenotypes when expressed in the yeast Saccharomyces cerevisiae. This observation suggests that yeast growth inhibition can be used as an indicator of protein translocation in functional genomic screens. However, limited information is available regarding the behavior of non-translocated proteins in yeast. We developed a semi-automated quantitative assay to monitor the growth of hundreds of yeast strains in parallel. We observed that expression of half of the 19 Shigella translocated proteins tested but almost none of the 20 non-translocated Shigella proteins nor ~1,000 Francisella tularensis proteins significantly inhibited yeast growth. Not only does this study establish that yeast growth inhibition is a sensitive and specific indicator of translocated proteins, but we also identified a new substrate of the Shigella type III secretion system (TTSS), IpaJ, previously missed by other experimental approaches. In those cases where the mechanisms of action of the translocated proteins are known, significant yeast growth inhibition correlated with the targeting of conserved cellular processes. By providing positive rather than negative indication of activity our assay complements existing approaches for identification of translocated proteins. In addition, because this assay only requires genomic DNA it is particularly valuable for studying pathogens that are difficult to genetically manipulate or dangerous to culture.
The Real Density Matrix
Timothy F. Havel
Physics , 2003,
Abstract: We introduce a nonsymmetric real matrix which contains all the information that the usual Hermitian density matrix does, and which has exactly the same tensor product structure. The properties of this matrix are analyzed in detail in the case of multi-qubit (e.g. spin = 1/2) systems, where the transformation between the real and Hermitian density matrices is given explicitly as an operator sum, and used to convert the essential equations of the density matrix formalism into the real domain.
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