Squamous cell carcinoma of the prostate: case report and review of literature

Carcinoma of the prostate, that is adenocarcinoma, is one of the most common malignancies in the male with an estimated incidence for 1991 of 122,000 new cases. On the other hand, squamous cell carcinoma of the prostate, with a median incidence of .5%-1% of all prostatic malignancies, has a similar clinical presentation but differs in treatment response and prognosis. We herein present one case of this histological pattern and review the literature pertaining to it.     

Room-temperature laser emission of GaInNAs-GaAs quantum wells grown on GaAs (111)B

In this work, we present room-temperature laser emission at 1.206 /spl mu/m from GaInNAs-GaAs quantum-well (QW) laser diodes (LDs) grown on misoriented GaAs (111)B substrates for the first time. Details of the structure and the molecular beam epitaxial growth of the lasers are discussed. We found that the postgrowth rapid thermal annealing increased the optimum emission, while the in situ self annealing effect in these QWs is almost negligible. The optimum annealing cycle (30 s at 850/spl deg/C) is comparable to that found for the cladding-free GaInNAs single QW samples grown on GaAs (111)B. Finally, the optical and electrical characterization of these LD devices is presented. The LDs show a room-temperature threshold current density of 2.15 kA/cm/sup 2/, with a differential quantum efficiency of 37%, under pulsed conditions.     

Involvement of gamma and beta actin isoforms in mouse neuroblastoma differentiation

Two actin isoforms, gamma and beta, are contained within neuroblastoma cells. However, the relative amount and distribution of both isoforms within the cells are differentially regulated during neurite extension. The proportion of gamma-actin isoform became about four times greater than that of beta actin during neuroblastoma cell differentiation. Additionally, whereas beta actin appears to be concentrated in the cell cortex, gamma actin is also present throughout the cell body. Upon differentiation, neuroblastoma cells reorganize their actin cytoskeleton and gamma actin is induced to polymerize whereas beta actin polymers are partially disassembled. Moreover, both actin isoforms are differentially distributed within differentiated cells. Thus, gamma actin polymers are located both in the soma and proximal regions of extended neurites, whereas beta actin is enriched in the terminal tip of the neurites. Our results strongly suggest that both actin isoforms are involved in a different way in neuroblastoma cell differentiation.     

Towards a consolidated model for a collaborative courseware authoring system

Abstract In an effort to reduce the expensive resource requirements in courseware production and to allow effective management of, and communication and collaboration between authors, a model is needed to harmonize the diverse theoretical backgrounds such a process requires. To this end we look at five abstract models which where chosen for their apparent appropriateness within the general area of collaborative authoring and reuse of multimedia courseware. These models consist of a functional model of hypertext, an infrastructure model for an open collaborative authoring system, two object-oriented communication models, and a courseware production model. We attempt a consolidation of these models and ultimately make several conclusions, which are exposed during a conceptual harmonisation. The principal conclusion is that a hypermedia logical model is not by itself adequate to support collaboration and reuse. Our modeling conclusions have driven the design of a system which will be implemented and tested.     

Modeling of Transport Through Submicron Semiconductor Structures: A Direct Solution to the Coupled Poisson-Boltzmann Equations

We report on a computational approach based on the self-consistent solution of the steady-state Boltzmann transport equation coupled with the Poisson equation for the study of inhomogeneous transport in deep submicron semiconductor structures. The nonlinear, coupled Poisson-Boltzmann system is solved numerically using finite difference and relaxation methods. We demonstrate our method by calculating the high-temperature transport characteristics of an inhomogeneously doped submicron GaAs structure where the large and inhomogeneous built-in fields produce an interesting fine structure in the high-energy tail of the electron velocity distribution, which in general is very far from a drifted-Maxwellian picture.     

Impact of N on the atomic-scale Sb distribution in quaternary GaAsSbN-capped InAs quantum dots

The use of GaAsSbN capping layers on InAs/GaAs quantum dots (QDs) has recently been proposed for micro- and optoelectronic applications for their ability to independently tailor electron and hole confinement potentials. However, there is a lack of knowledge about the structural and compositional changes associated with the process of simultaneous Sb and N incorporation. In the present work, we have characterized using transmission electron microscopy techniques the effects of adding N in the GaAsSb/InAs/GaAs QD system. Firstly, strain maps of the regions away from the InAs QDs had revealed a huge reduction of the strain fields with the N incorporation but a higher inhomogeneity, which points to a composition modulation enhancement with the presence of Sb-rich and Sb-poor regions in the range of a few nanometers. On the other hand, the average strain in the QDs and surroundings is also similar in both cases. It could be explained by the accumulation of Sb above the QDs, compensating the tensile strain induced by the N incorporation together with an In-Ga intermixing inhibition. Indeed, compositional maps of column resolution from aberration-corrected Z-contrast images confirmed that the addition of N enhances the preferential deposition of Sb above the InAs QD, giving rise to an undulation of the growth front. As an outcome, the strong redshift in the photoluminescence spectrum of the GaAsSbN sample cannot be attributed only to the N-related reduction of the conduction band offset but also to an enhancement of the effect of Sb on the QD band structure.     

Estimation of the diffusivities of sodium chloride,potassium sorbate and sodium bisulphite in mango slices processed by hurdle technology

The fractional amount of sodium chloride, potassium sorbate and sodium bisulphite were evaluated in mango slices immersed in limited volumes of syrup at 25, 50 and 70 °C. The syrup contained 250 g sucrose, 1.5 g sodium chloride, 0.5 g potassium sorbate and 0.25 g sodium bisulphate per kilogram of solution. The sodium chloride concentration in the syrup was confirmed with a flame photometer, and the concentrations of potassium sorbate and sodium bisulphite were determined using high-performance liquid chromatography (HPLC). Fick’s second law was used to calculate effective diffusion coefficients and to predict solute content in the mango slices. Diffusion coefficients were affected by temperature and were correlated by the Arrhenius equation. The experimental data fit the proposed mathematical model well, allowing prediction of the system’s behavior at different temperatures. The resultant diffusivities ranges were 2.63–3.54 × 10^?9 m²/s for sodium chloride, 3.88 × 10^?9–8.3 × 10^?10 m²/s for potassium sorbate and 1.83 × 10^?7–5.98 × 10^-8 m²/s for sodium bisulphite.     

MBE growth and processing of diluted nitride quantum well lasers on GaAs (1 1 1)B

We have grown by Molecular Beam Epitaxy GaInNAs/GaAs (1 1 1)B quantum wells (QWs) embedded in p-i-n diode and laser diode structures. The impact of the different growth parameters (As flux, growth temperature, growth rate, ion density) on the optical and structural properties of this material is studied by Photoluminescence and Atomic Force Microscopy. Additionally, systematic studies of rapid thermal annealing cycles have been performed to optimize the laser structures. Finally, edge-emitting laser diodes have been processed using these structures. These devices showed room-temperature laser emission above 1.2 μm under pulsed current conditions.