In order to evaluate the effectiveness of CdTe surface passivating layers, HgCdTe photoconductors with and without CdTe sidewall passivation were fabricated. As expected, photoconductors with CdTe ...sidewall passivation demonstrated significantly higher responsivity in comparison with those without sidewall passivation, indicating the effectiveness of molecular-beam epitaxially (MBE)-grown CdTe as a passivation layer in reducing surface recombination velocity. Characterization of the responsivity differences between photoconductors with and without sidewall CdTe passivation offers a potential method for measuring the interface/surface recombination velocity. This has been demonstrated in this paper by extracting the value of the surface recombination velocity using the Synopsys Sentaurus commercial modeling package to fit experimental responsivity data for fully and partially passivated devices.
Managing manure in reduced tillage and forage systems presents challenges, as incorporation by tillage is not compatible. Surface-applied manure that is not quickly incorporated into soil provides ...inefficient delivery of manure nutrients to crops due to environmental losses through ammonia (NH3) volatilization and nutrient losses in runoff, and serves as a major source of nuisance odors. An array of technologies now exist to facilitate the incorporation of liquid manures into soil with restricted or minor soil disturbance, some of which are new: shallow disk injection; chisel injection; aeration infiltration; pressure injection. Surface banding of manure in forages decreases NH3 emissions relative to surface broadcasting, as the canopy can decrease wind speed over the manure, but greater reductions can be achieved with manure injection. Soil aeration is intended to hasten manure infiltration, but its benefits are not consistent and may be related to factors such as soil drainage characteristics. Work remains to be done on refining its method of use and timing relative to manure application, which may improve its effectiveness. Placing manure under the soil surface by injection offers much promise to improve N use efficiency through less NH3 volatilization, reduced odors and decreased nutrient losses in runoff, relative to surface application. We identified significant gaps in our knowledge as many of these technologies are relatively new, and this should help target future research efforts including environmental, agronomic, and economic assessments.
The electrical properties of semiconductor materials have conventionally been extracted via Hall measurements performed at a single magnetic field. When applied to a semiconductor such as HgCdTe with ...mixed conduction characteristics, the values obtained from the Hall measurement represent only an averaged contribution of all carriers present in the sample. In this study, the transport properties of a liquid-phase epitaxially (LPE) grown p-type HgCdTe were determined. Variable magnetic field and temperature Hall and resistivity measurements were employed in conjunction with the improved-quantitative mobility spectrum analysis (iQMSA) algorithm to extract the concentrations and mobilities of all carriers present in the material. A comparison study was made between a van der Pauw Greek cross and a standard Hall bar structure on the same material. A disparity in the transport property of the sample was observed when both structures were measured within a few days of each other. Through iQMSA analysis, the discrepancy is seen to be attributed to the formation of an n-type skin inversion layer within a week after processing.
State-of-the-art: rheumatoid arthritis McInnes, Iain B; O'Dell, James R
Annals of the rheumatic diseases,
11/2010, Volume:
69, Issue:
11
Journal Article
Peer reviewed
The understanding of the pathogenesis and optimal therapeutics for rheumatoid arthritis (RA) has advanced remarkably over the last decade. This review highlights these key advances, particularly the ...outcomes of genome-wide scans which have provided an increasingly robust appraisal of the complex genetics that underpin RA. Such observations are placed in pathogenetic context, particularly concerning the breach of tolerance that presages synovitis and the mechanisms that subserve chronicity. The key therapeutic strategies and treatment agents, both conventional and biological, now available to effectively manage the disease are described. Throughout the review, emphasis is placed on unanswered questions and challenges in this exciting field.
Novel Antioxidant Properties of Doxycycline Clemens, Dahn L; Duryee, Michael J; Sarmiento, Cleofes ...
International journal of molecular sciences,
12/2018, Volume:
19, Issue:
12
Journal Article
Peer reviewed
Open access
Doxycycline (DOX), a derivative of tetracycline, is a broad-spectrum antibiotic that exhibits a number of therapeutic activities in addition to its antibacterial properties. For example, DOX has been ...used in the management of a number of diseases characterized by chronic inflammation. One potential mechanism by which DOX inhibits the progression of these diseases is by reducing oxidative stress, thereby inhibiting subsequent lipid peroxidation and inflammatory responses. Herein, we tested the hypothesis that DOX directly scavenges reactive oxygen species (ROS) and inhibits the formation of redox-mediated malondialdehyde-acetaldehyde (MAA) protein adducts. Using a cell-free system, we demonstrated that DOX scavenged reactive oxygen species (ROS) produced during the formation of MAA-adducts and inhibits the formation of MAA-protein adducts. To determine whether DOX scavenges specific ROS, we examined the ability of DOX to directly scavenge superoxide and hydrogen peroxide. Using electron paramagnetic resonance (EPR) spectroscopy, we found that DOX directly scavenged superoxide, but not hydrogen peroxide. Additionally, we found that DOX inhibits MAA-induced activation of Nrf2, a redox-sensitive transcription factor. Together, these findings demonstrate the under-recognized direct antioxidant property of DOX that may help to explain its therapeutic potential in the treatment of conditions characterized by chronic inflammation and increased oxidative stress.
Beta-adrenergic receptors (β-ARs) critically modulate long-lasting synaptic plasticity and long-term memory storage in the mammalian brain. Synaptic plasticity is widely believed to mediate memory ...storage at the cellular level. Long-term potentiation (LTP) is one type of synaptic plasticity that has been linked to memory storage. Activation of β-ARs can enhance LTP and facilitate long-term memory storage. Interestingly, many of the molecular signaling pathways that are critical for β-adrenergic modulation of LTP mirror those required for the persistence of memory. In this article, we review the roles of signaling cascades and translation regulation in enabling β-ARs to control expression of long-lasting LTP in the rodent hippocampus. These include the cyclic-AMP/protein kinase-A (cAMP–PKA) and extracellular signal-regulated protein kinase cascades, two key pathways known to link transmitter receptors with translation regulation. Future research directions are discussed, with emphasis on defining the roles of signaling complexes (e.g. PSD-95) and glutamatergic receptors in controlling the efficacy of β-AR modulation of LTP.
The semiconductor-passivating layer interfaces, as well as their dielectric properties, play important and very often dominant roles in determining HgCdTe device performance. In this work, ...photoconductors were fabricated on p-type mid-wave infrared Hg 1-x Cd x Te material using molecular beam epitaxy (MBE) grown CdTe film as the passivation layer. In order to emphasize the importance of the CdTe passivating layer, HgCdTe photoconductors with and without the sidewall CdTe passivation were fabricated. The photoconductor with its sidewalls passivated shows significantly higher responsivity than the one without sidewall passivation. Conductance-voltage characteristics of capacitor using CdTe between HgCdTe and metal contacts were made in studying insulating property of the passivation film. Scanning electron microscopy (SEM) micrographs and X-ray diffraction (XRD) spectra were included in order to investigate the structural properties of the CdTe passivation film.
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