Nature of the acceptor responsible for p-type conduction in liquid encapsulated Czochralski-grown undoped gallium antimonide

The acceptors in undoped liquid encapsulated Czochralski (LEC)-grown GaSb were investigated using temperature dependent Hall (TDH) and positron lifetime spectroscopy measurements. TDH measurements were performed on nonirradiated and electron irradiated undoped samples. The 34 meV acceptor was found to be the important one responsible for the p-type conduction in nonirradiated and the e--irradiated undoped materials annealed at temperatures up to 500°C. This acceptor was not related to any VGa-related defect detected and was most likely the GaSb antisite.published_or_final_versio

Optimization of Transparent Electrode Processing Conditions for Bulk Heterojunction Solar Cells

In this work, semi-transparent inverted polymer solar cells with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate; PEDOT:PSS) top electrodes were fabricated by spin-coating process. Poly(3-hexylthiophene; P3HT):[6,6]-phenyl C 61 -butyric acid methyl ester (PCBM) was used as a model material combination for a bulk heterojunction solar cell, because this material combination has been frequently studied, and its properties and performance have been well established. For enhancing the wetting of P3HT:PCBM blend film, different plasma etching conditions were tried. In addition, different high boiling point organic additives were tried to enhance the conductivity of PEDOT:PSS. The performance of solar cells with different fabrication conditions for the top electrode was compared. The best performance was obtained for Ar plasma etching to improve wetting of PEDOT:PSS and the addition of ethylene glycol to improve conductivity.published_or_final_versio

Deconvolution of positron annihilation coincidence Doppler broadening spectra using an iterative projected Newton method with non-negativity constraints

A generalized least-square method with Tikonov-Miller regularization and non-negativity constarints was developed for deconvoluting two-dimensional coincidence Doppler broadening spectroscopy (CDBS) spectra. A projected Newton algorithm was developed to solve the generalized least-square problem. The algorithm was used to deconvolute experimental CDBS data from aluminum was tested on Monte Carlo generated spectra. The retrieval of the positron-electron momentum distributions in the low momentum region was also demonstrated.published_or_final_versio

Indium tin oxide nanowires growth by dc sputtering

Indium tin oxide nanowires have been grown by dc sputtering on different substrates without the use of catalysts or oblique deposition. The nanowire length was of the order of several μm, while their diameter was ∼50- 100 nm. Small side branches on the nanowires were frequently observed. The nanowires were characterized by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The growth mechanism of the nanowires is discussed. © Springer-Verlag 2011.published_or_final_versionSpringer Open Choice, 21 Feb 201

Anode modification of polyfluorene-based polymer light-emitting devices

A glycerol-modified poly(3,4-ethylene dioxythiophene) (PEDOT): poly(styrene sulfonate) (PSS) layer was used as an anode buffer layer in polymer light-emitting devices using poly(9,9-dioctylfluorene) (F8) as the emitter. Devices with a configuration of indium tin oxide/PEDOT:PSS (with or without glycerol)/F8/CsF/Al were fabricated. It was found that the glycerol-modified device showed a much larger current density than the unmodified device. At an operating voltage of 6 V, the glycerol-modified device showed a luminance of 1300Cd/m 2 and a current efficiency of 1.7 Cd/A compared to the corresponding values of 500Cd/m 2 and 1.3 Cd/A in the unmodified device. Analysis by ultraviolet spectroscopy suggests that the two devices have the same energy level structure and the performance improvement should not be due to change in the PEDOT/polymer interface. It was further found that incorporating a suitable amount of glycerol into the PEDOT:PSS layer can increase its conductivity by six times. This leads to a better balance in the hole and electron currents and thus improved device efficiency. © 2002 American Institute of Physics.published_or_final_versio

Low energy electron irradiation induced deep level defects in 6H-SiC: The implication for the microstructure of the deep levels E1/E 2

The deep level defects in 6H-SiC induced by low energy electron irradiation was investigated. Electron energies of 0.2, 0.3, 0.5 and 1.7 MeV were used to produce the deep level defects in the n-type 6H-SiC materials. The deep level transient spectroscopy (DLTS) technique, combined with isochronal thermal annealing experiments, was used for the study of the defects. It was observed that deep levels ED1, E1/E2 and Ei were created with irradiation energies of 0.3 MeV or greater than that. The deep levels were found to be associated with primary atom displacement on the C atom of SiC sublattice and had microstructure containing the carbon vacancy.published_or_final_versio

Diabetic retinopathy for the non-ophthalmologist

Diabetic retinopathy is a microangiopathy resulting from the chronic effects of diabetes mellitus. Healthcare professionals often work in isolation to deliver highly specialised care efficiently and effectively for people living with diabetes. It is not uncommon for people with diabetes to be making frequent visits to community and hospital clinics to see a variety of specialists and healthcare professionals, with seemingly little opportunity for coordination of this complex health management programme between the wider team. In a field that is so diverse and rapidly changing, healthcare professionals of all specialties need to be aware of developments across all aspects of diabetes management. In this article, we discuss the epidemiology and natural history of diabetic retinopathy and describe an approach to its assessment and diagnosis. We provide an overview of the principles of diabetic retinopathy management and outline possible future treatments for diabetic retinopathy

Meditation-induced neuroplastic changes in amygdala activity during negative affective processing

Recent evidence suggests that the effects of meditation practice on affective processing and resilience have the potential to induce neuroplastic changes within the amygdala. Notably, literature speculates that meditation training may reduce amygdala activity during negative affective processing. Nonetheless, studies have thus far not verified this speculation. In this longitudinal study, participants (N = 21, 9 men) were trained in awareness-based compassion meditation (ABCM) or matched relaxation training. The effects of meditation training on amygdala activity were examined during passive viewing of affective and neutral stimuli in a non-meditative state. We found that the ABCM group exhibited significantly reduced anxiety and right amygdala activity during negative emotion processing than the relaxation group. Furthermore, ABCM participants who performed more compassion practice had stronger right amygdala activity reduction during negative emotion processing. The lower right amygdala activity after ABCM training may be associated with a general reduction in reactivity and distress. As all participants performed the emotion processing task in a non-meditative state, it appears likely that the changes in right amygdala activity are carried over from the meditation practice into the non-meditative state. These findings suggest that the distress-reducing effects of meditation practice on affective processing may transfer to ordinary states, which have important implications on stress management.Department of Rehabilitation Sciences2016-2017 > Academic research: refereed > Publication in refereed journalbcr

Simvastatin improves the sexual health-related quality of life in men aged 40 years and over with erectile dysfunction : Additional data from the Erectile Dysfunction and Statin trial

© 2014 Trivedi et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Background: Erectile dysfunction is prevalent in men over 40 years, affecting their quality of life and that of their partners. The aims of this study were:a)To evaluate the internal reliability of the male erectile dysfunction specific quality of life (MED-QoL) scale and explore its factor structure.b)To evaluate the effect of simvastatin on subscales of the MED-QoL in men over forty years with erectile dysfunction. Methods: This is a double blind randomised controlled trial of 40 mg simvastatin or placebo given once daily for six months to men over forty years with untreated erectile dysfunction, who were not at high cardiovascular risk and were not on anti-hypertensive or lipid-lowering medication. 173 eligible men were recruited from 10 general practices in East of England. Data were collected at two points over 30 weeks. We report on the factor structure of MED-QoL, the internal reliability of the scale and the derived subscales, and the effect of simvastatin on MED-QoL subscales. Results: An initial analysis of the MED-QoL items suggested that a number of items should be removed (MED-QoL-R). Exploratory factor analysis identified three subscales within the MED-QoL-R which accounted for 96% of the variance, related to feelings of Control, initiating Intimacy, and Emotional response to erectile dysfunction. The alpha value for the revised scale (MED-Qol-R) was >0.95 and exceeded .82 for each subscale. Regression analysis showed that patients in the placebo group experienced a significantly reduced feeling of Control over erectile dysfunction than those in the statin group. Those in the placebo group had significantly lower Emotional response than those in the statin group at the close of trial, but there was no significant treatment effect on Intimacy. Conclusions: Our revised MED-QoL-R identified three subscales. Secondary analysis showed a significant improvement in sexual health related quality of life, specifically in relation to perception of control and emotional health in men with untreated erectile dysfunction given 40 mg simvastatin for six months. Trial registration: Current Controlled Trials ISRCTN66772971.Peer reviewe