Substantial CT radiation dose reduction does not affect the preference for CT over direct digital radiography to diagnose isolated zygomatic fractures:a study in human cadavers

Introduction: Zygomatic fractures can be diagnosed with either computed tomography (CT) or direct digital radiography (DR). The aim of the present study was to assess the effect of CT dose reduction on the preference for facial CT versus DR for accurate diagnosis of isolated zygomatic fractures. Materials and methods: Eight zygomatic fractures were inflicted on four human cadavers with a free fall impactor technique. The cadavers were scanned using eight CT protocols, which were identical except for a systematic decrease in radiation dose per protocol, and one DR protocol. Single axial CT images were displayed alongside a DR image of the same fracture creating a total of 64 dual images for comparison. A total of 54 observers, including radiologists, radiographers and oral and maxillofacial surgeons, made a forced choice for either CT or DR. Results: Forty out of 54 observers (74%) preferred CT over DR (all with P < 0.05). Preference for CT was maintained even when radiation dose reduced from 147.4 mSv to 46.4 mSv (DR dose was 6.9 mSv). Only a single out of all raters preferred DR (P ¼ 0.0003). The remaining 13 observers had no significant preference. Conclusion: This study demonstrates that preference for axial CT over DR is not affected by substantial (~70%) CT dose reduction for the assessment of zygomatico-orbital fractures

Measurement of antiacetylcholine receptor auto-antibodies in myasthenia gravis

Two different acetylcholine receptor (AChR) preparations derived from amputated human muscle (AChRAMP) and from the human rhabdomyosarcoma cell line TE671 (AChRTE67,) were compared in radio-immunoprecipitation assays for the detection of AChR auto-antibodies in serum specimens from 20 patients with proven myasthenia gravis. Tests performed with the AChRTE67, and AChRAMP antigen preparations were positive in all the patients and in 19/20 respectively. A high degree of correlation (r = 0,94) was evident between the two auto-antigen preparations. Assays based on the use of TE671-derived antigen represent a useful alternative to the conventional assay using AChRAMP  for the detection of AChR autoantibodies

Genotyping of Chlamydophila psittaci in Human Samples

Chlamydophila (formerly Chlamydia) psittaci genotypes A, B, C, and a new genotype most similar to the 6BC type strain were found in 10 humans with psittacosis by outer membrane protein A gene sequencing. Genotypes B (n = 3) and C (n = 1) are endemic in nonpsittacine European birds. These birds may represent an important part of the zoonotic reservoir

Psychedelics Promote Structural and Functional Neural Plasticity.

Atrophy of neurons in the prefrontal cortex (PFC) plays a key role in the pathophysiology of depression and related disorders. The ability to promote both&nbsp;structural and functional plasticity in the PFC has been hypothesized to underlie the fast-acting antidepressant properties of the dissociative anesthetic ketamine. Here, we report that, like ketamine, serotonergic psychedelics are capable of robustly increasing neuritogenesis and/or spinogenesis both in&nbsp;vitro and in&nbsp;vivo. These changes in neuronal structure are accompanied by increased synapse number and function, as measured by fluorescence microscopy and electrophysiology. The structural changes induced by psychedelics appear to result from stimulation of the TrkB, mTOR, and 5-HT2A signaling pathways and could possibly explain the clinical effectiveness of these compounds. Our results underscore the therapeutic potential of psychedelics and, importantly, identify several lead scaffolds for medicinal chemistry efforts focused on developing plasticity-promoting compounds as safe, effective, and fast-acting treatments for depression and related disorders

Tuning the Energetic Landscape of Ruddlesden-Popper Perovskite Films for Efficient Solar Cells

Ruddlesden-Popper perovskite films deposited with different methods show very diverse phase segregation and composition. When DMSO is used as solvent, the conventional method based on spin-coating and annealing produces very poor devices, whereas the vacuum-assisted method proposed here allows obtaining devices with efficiency up to 14.14%. The conventional method gives rise to a three-dimensional (3D)-like phase on the top of the film but dominant n = 2 phase with large domains (∼40 μm) at the bottom of the film. These n = 2 domains are oriented with their inorganic slabs parallel to the substrate and inhibit the charge transport in the vertical direction. Consequently, severe monomolecular and bimolecular charge recombination occurs in the solar cells. Conversely, the vacuum-assisted method yields films with a 3D-like phase dominant throughout their entire thickness and only a small amount of n ≤ 2 domains of limited dimensions (∼3 μm) at the bottom, which facilitate charge transport and reduce charge recombination

Tuning the Energetic Landscape of Ruddlesden-Popper Perovskite Films for Efficient Solar Cells

Ruddlesden-Popper perovskite films deposited with different methods show very diverse phase segregation and composition. When DMSO is used as solvent, the conventional method based on spin-coating and annealing produces very poor devices, whereas the vacuum-assisted method proposed here allows obtaining devices with efficiency up to 14.14%. The conventional method gives rise to a three-dimensional (3D)-like phase on the top of the film but dominant n = 2 phase with large domains (∼40 μm) at the bottom of the film. These n = 2 domains are oriented with their inorganic slabs parallel to the substrate and inhibit the charge transport in the vertical direction. Consequently, severe monomolecular and bimolecular charge recombination occurs in the solar cells. Conversely, the vacuum-assisted method yields films with a 3D-like phase dominant throughout their entire thickness and only a small amount of n ≤ 2 domains of limited dimensions (∼3 μm) at the bottom, which facilitate charge transport and reduce charge recombination.</p

The 74MHz System on the Very Large Array

The Naval Research Laboratory and the National Radio Astronomy Observatory completed implementation of a low frequency capability on the VLA at 73.8 MHz in 1998. This frequency band offers unprecedented sensitivity (~25 mJy/beam) and resolution (~25 arcsec) for low-frequency observations. We review the hardware, the calibration and imaging strategies, comparing them to those at higher frequencies, including aspects of interference excision and wide-field imaging. Ionospheric phase fluctuations pose the major difficulty in calibrating the array. Over restricted fields of view or at times of extremely quiescent ionospheric ``weather'', an angle-invariant calibration strategy can be used. In this approach a single phase correction is devised for each antenna, typically via self-calibration. Over larger fields of view or at times of more normal ionospheric ``weather'' when the ionospheric isoplanatic patch size is smaller than the field of view, we adopt a field-based strategy in which the phase correction depends upon location within the field of view. This second calibration strategy was implemented by modeling the ionosphere above the array using Zernike polynomials. Images of 3C sources of moderate strength are provided as examples of routine, angle-invariant calibration and imaging. Flux density measurements indicate that the 74 MHz flux scale at the VLA is stable to a few percent, and tied to the Baars et al. value of Cygnus A at the 5 percent level. We also present an example of a wide-field image, devoid of bright objects and containing hundreds of weaker sources, constructed from the field-based calibration. We close with a summary of lessons the 74 MHz system offers as a model for new and developing low-frequency telescopes. (Abridged)Comment: 73 pages, 46 jpeg figures, to appear in ApJ

Photochromism in Ruddlesden-Popper copper-based perovskites:A light-induced change of coordination number at the surface

Ruddlesden-Popper organic-inorganic hybrid copper-based perovskites have been studied for decades owing to a variety of interesting properties, such as thermochromism and piezochromism, and the mechanisms behind these phenomena have been explained. Another possible property of these materials that has seldomly been investigated is photochromism. In this work, the photochromic properties of bis(phenethylammonium) tetrachlorocuprate (also known as phenethylammonium copper chloride) are reported for the first time. This material has attracted scientific interest owing to the fact that it shows both ferroelectric and ferromagnetic behavior. This work highlights the difference in stability between two Ruddlesden-Popper copper-based perovskites - with phenethylammonium (PEA) or methylammonium (MA) as the cations - during external stimuli. Various techniques, such as Raman and X-ray photoelectron spectroscopy, and grazing-incidence wide-angle X-ray scattering, combined with optical studies, were used to investigate the underlying photochemical processes at a molecular level. It is found that for the PEA compound, ultraviolet illumination causes a color change from yellow to brown. This is the result of two independent events, namely a Cu2+ reduction reaction and a transition from an octahedral copper-chloride structure to square-planar CuCl42-. After illumination, the material (brown color) is unstable in air, which is evident from a color change back to yellow. Interestingly, the similar compound bis(methylammonium) tetrachlorocuprate does not display photochromic behavior, which is attributed to the different nature of the two organic cations

Carotid intima-media thickness and its associations with type 2 diabetes mellitus in South Africans

OBJECTIVES: Carotid intima-media thickness (CIMT) is a surrogate marker of subclinical atherosclerosis and a predictor of cardiovascular events. Few studies in Africa have evaluated CIMT and its associations in people with type 2 diabetes mellitus. This study measured CIMT in a sample of mainly black South African patients with type 2 diabetes mellitus, and evaluated the association of demographic and clinical risk factors with CIMT. DESIGN: Cross-sectional study. SETTING: Kafalong Hospital, a large community hospital in Pretoria that mainly serves an urban black community. SUBJECTS: Patients with type 2 diabetes mellitus. OUTCOME MEASURES: We evaluated clinical, biochemical and CIMT ultrasound measurements in a standardised fashion. RESULTS: In 185 patients, the univariate significant predictors of mean far-wall CIMT were age [beta 0.007 (standard error 0.001)], systolic blood pressure [beta 0.001 (standard error 0.000)] and inverse serum creatinine [beta -8.15 (standard error 3.23)]. Low-density lipoprotein cholesterol, apolipoprotein A-1, apolipoprotein B:A-1 ratio and apolipoprotein B:A-1 ratio > 1.2 all had p-values below 0.1, but above 0.05. Age had the largest R-squared (20%). The multivariate models did not explain more of the variation in CIMT than did age alone. CONCLUSION: Lipid parameters were related to CIMT in our study population. However, this did not reach statistical significance in this relatively small sample, and lipids added very little to the variability of CIMT compared with age alone.http://www.jemdsa.co.za/index.php/JEMDSAay201