Debates in the Digital Humanities Formerly Known as Humanities Computing

published_or_final_versio

Transmembrane protein PERP is a component of tessellate junctions and of other junctional and non-junctional plasma membrane regions in diverse epithelial and epithelium-derived cells

Protein PERP (p53 apoptosis effector related to PMP-22) is a small (21.4 kDa) transmembrane polypeptide with an amino acid sequence indicative of a tetraspanin character. It is enriched in the plasma membrane and apparently contributes to cell-cell contacts. Hitherto, it has been reported to be exclusively a component of desmosomes of some stratified epithelia. However, by using a series of newly generated mono- and polyclonal antibodies, we show that protein PERP is not only present in all kinds of stratified epithelia but also occurs in simple, columnar, complex and transitional epithelia, in various types of squamous metaplasia and epithelium-derived tumors, in diverse epithelium-derived cell cultures and in myocardial tissue. Immunofluorescence and immunoelectron microscopy allow us to localize PERP predominantly in small intradesmosomal locations and in variously sized, junction-like peri- and interdesmosomal regions (“tessellate junctions”), mostly in mosaic or amalgamated combinations with other molecules believed, to date, to be exclusive components of tight and adherens junctions. In the heart, PERP is a major component of the composite junctions of the intercalated disks connecting cardiomyocytes. Finally, protein PERP is a cobblestone-like general component of special plasma membrane regions such as the bile canaliculi of liver and subapical-to-lateral zones of diverse columnar epithelia and upper urothelial cell layers. We discuss possible organizational and architectonic functions of protein PERP and its potential value as an immunohistochemical diagnostic marker

Room Temperature CW Operation of GaInAsSb/AlGaAsSb Quantum Well Lasers Emitting in the 2.2 to 2.3µm Wavelength Range

AbstractWe report on room temperature cw operation of type-I semiconductor quantum well (QW) laser diodes based on the GaInAsSb/AIGaAsSb/GaSb material system emitting beyond 2.2 µm. Lasing is observed in cw mode up to at least 320 K. A high internal quantum efficiency of 65% and a low internal loss coefficient of 5 cm1have been achieved for a single QW (SQW)large optical cavity laser at 280 K. An extrapolated threshold current density for infinite cavity length of 144 A/cm2and 55 A/cm2has been deduced for the 3 QW and SQW lasers, respectively, which scales with the number of QWs. A maximum cw light output power of 230 mW at 280 K heatsink temperature was obtained for a 3 QW large optical cavity laser with HR/AR coated mirror facets, mounted substrate-side down.</jats:p

Sb-Based Mid-Infrared Diode Lasers

AbstractIn this paper we review recent progress achieved in our development of type-I GaInAsSb/AlGaAsSb quantum-well (QW) lasers with emission wavelength in the 1.74–2.34 μm range. Triple-QW (3-QW) and single-QW (SQW) diode lasers having broadened waveguide design emitting around 2.26 μm have been studied in particular. Comparing the two designs we have find that the threshold current density at infinite cavity length as well as the transparency current density scale with the number of QWs. Maximum cw operating temperature exceeding 50°C and 90°C has been obtained for ridge waveguide lasers emitting above and below 2 μm, respectively. Ridge waveguide diode lasers emitting at 1.94 μm exhibited internal quantum efficiencies in excess of 77%, internal losses of 6 cm−1, and threshold current density at infinite cavity length as low as 121 A/cm2 reflecting the superior quality of our diode lasers, all values recorded at 280 K. A high characteristic temperature TOof 179 K for the threshold current along with a value of T1 = 433 K for the characteristic temperature of the external efficiency have been attained for the 240–280 K temperature interval. Room temperature cw output powers exceeding 1.7 W have been demonstrated for broad area single element devices with highreflection/ antireflection coated mirror facets, mounted epi-side down. The latter result is a proof for the high power capabilities of these GaSb-based mid-ir diode lasers.</jats:p