Retinal toxicity of intravitreal triamcinolone acetonide: a morphological study

Purpose: To evaluate the morphologic effects of intravitreal triamcinolone acetonide (TA) on rabbit retina. Methods: Intravitreal injections of 0.5 mg, 1 mg, 4 mg, 8 mg, and 20 mg of TA (Kenalog-40; Bristol-Myers Squibb, Princeton, NJ) in 0.1 mL were given to pigmented rabbits. For control, 0.1 mL of TA vehicle and saline were injected. Animals were killed on day 14, and retinas were analyzed by light as well as electron microscopy. Results: No ophthalmoscopic change was found. Eyes injected with 0.5 mg and 1 mg of TA did not have morphologic abnormality. Eyes injected with 4 mg, 8 mg, and 20 mg showed destruction of photoreceptor outer segments and migration of macrophage-like cells in the subretinal space. Eyes injected with 20 mg showed more extensive damage and increased pigment granules in the retinal pigment epithelium cells with large oil droplets in the cytoplasm. Electron microscopy also showed loss of photoreceptor/retinal pigment epithelium interdigitations. Eyes injected with vehicle or saline did not show morphologic changes. Conclusion: Single intravitreal injection of 0.5 mg or 1 mg of TA did not produce morphologic retinal changes in pigmented rabbits. However, injections of 4 mg, 8 mg, and 20 mg of TA produced outer retina toxic effects. These findings suggest that long-term retinal toxicity studies should be carried out, using single and repeated injections before this therapy becomes more widely used

The Influences of Diesel Particulate Filter Installation on Air Pollutant Emissions for Used Vehicles

Three kinds of diesel particulate filters (DPFs) were installed on used diesel-powered vehicles to investigate their influences on air pollutant emissions. The air pollutant emissions were measured before, after and running for specific distances to assess the deterioration effect. The emission measurement was performed on a chassis dynamometer. The results show that emissions of smoke, CO and HC are all reduced after DPF installation. After 20000 km driving, the emission concentrations of the above 3 criteria air pollutants do not increase in comparison with that right after installation. When DPFs are installed, the emissions of PAHs (polycyclic aromatic hydrocarbons) are reduced by 85.6-89.4% and 69.0-89.2% for heavy-duty diesel vehicles (HDVs) and light-duty diesel vehicles (LDVs), respectively. After driving 20000 km for HDVs and 2500 km for LDVs, PAH emissions do not increase in comparison with that right after installation, indicating that the DPFs do not deteriorate after driving for the test mileages. The lower molecular weight PAHs predominates in the exhaust both before and after DPF installation. The results also show the reduction rate is higher for higher molecular weight PAHs due to their tendency to adsorb on particulate

The Effects of Atmospheric Dispersion on High-Resolution Solar Spectroscopy

We investigate the effects of atmospheric dispersion on observations of the Sun at the ever-higher spatial resolutions afforded by increased apertures and improved techniques. The problems induced by atmospheric refraction are particularly significant for solar physics because the Sun is often best observed at low elevations, and the effect of the image displacement is not merely a loss of efficiency, but the mixing of information originating from different points on the solar surface. We calculate the magnitude of the atmospheric dispersion for the Sun during the year and examine the problems produced by this dispersion in both spectrographic and filter observations. We describe an observing technique for scanning spectrograph observations that minimizes the effects of the atmospheric dispersion while maintaining a regular scanning geometry. Such an approach could be useful for the new class of high-resolution solar spectrographs, such as SPINOR, POLIS, TRIPPEL, and ViSP

Glassy Vortex State in a Two-Dimensional Disordered XY-Model

The two-dimensional XY-model with random phase-shifts on bonds is studied. The analysis is based on a renormalization group for the replicated system. The model is shown to have an ordered phase with quasi long-range order. This ordered phase consists of a glass-like region at lower temperatures and of a non-glassy region at higher temperatures. The transition from the disordered phase into the ordered phase is not reentrant and is of a new universality class at zero temperature. In contrast to previous approaches the disorder strength is found to be renormalized to larger values. Several correlation functions are calculated for the ordered phase. They allow to identify not only the transition into the glassy phase but also an additional crossover line, where the disconnected vortex correlation changes its behavior on large scales non-analytically. The renormalization group approach yields the glassy features without a breaking of replica symmetry.Comment: latex 12 pages with 3 figures, using epsf.sty and multicol.st

An enrichment method for temperature-sensitive and auxotrophic mutants of yeast

An enrichment procedure that exploits the difference in heat-sensitivity between exponentially growing and stationary phase cells has been developed for the isolation of yeast mutants. Enrichments of up to 12-fold for temperature-sensitive lethal mutants and of up to 15-fold for auxotrophs have been obtained with single cycles of selection. Still higher enrichments (to frequencies of greater than 90% and 80% for temperature-sensitive lethals and auxotrophs, respectively) have been obtained with multiple cycles of selection. The method requires no special parent strain, and seems adaptable to the selection of a wide variety of types of mutants.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47545/1/438_2004_Article_BF00274022.pd

Stress corrosion cracking in Al-Zn-Mg-Cu aluminum alloys in saline environments

Copyright 2013 ASM International. This paper was published in Metallurgical and Materials Transactions A, 44A(3), 1230 - 1253, and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.Stress corrosion cracking of Al-Zn-Mg-Cu (AA7xxx) aluminum alloys exposed to saline environments at temperatures ranging from 293 K to 353 K (20 °C to 80 °C) has been reviewed with particular attention to the influences of alloy composition and temper, and bulk and local environmental conditions. Stress corrosion crack (SCC) growth rates at room temperature for peak- and over-aged tempers in saline environments are minimized for Al-Zn-Mg-Cu alloys containing less than ~8 wt pct Zn when Zn/Mg ratios are ranging from 2 to 3, excess magnesium levels are less than 1 wt pct, and copper content is either less than ~0.2 wt pct or ranging from 1.3 to 2 wt pct. A minimum chloride ion concentration of ~0.01 M is required for crack growth rates to exceed those in distilled water, which insures that the local solution pH in crack-tip regions can be maintained at less than 4. Crack growth rates in saline solution without other additions gradually increase with bulk chloride ion concentrations up to around 0.6 M NaCl, whereas in solutions with sufficiently low dichromate (or chromate), inhibitor additions are insensitive to the bulk chloride concentration and are typically at least double those observed without the additions. DCB specimens, fatigue pre-cracked in air before immersion in a saline environment, show an initial period with no detectible crack growth, followed by crack growth at the distilled water rate, and then transition to a higher crack growth rate typical of region 2 crack growth in the saline environment. Time spent in each stage depends on the type of pre-crack (“pop-in” vs fatigue), applied stress intensity factor, alloy chemistry, bulk environment, and, if applied, the external polarization. Apparent activation energies (E a) for SCC growth in Al-Zn-Mg-Cu alloys exposed to 0.6 M NaCl over the temperatures ranging from 293 K to 353 K (20 °C to 80 °C) for under-, peak-, and over-aged low-copper-containing alloys (~0.8 wt pct), they are typically ranging from 20 to 40 kJ/mol for under- and peak-aged alloys, and based on limited data, around 85 kJ/mol for over-aged tempers. This means that crack propagation in saline environments is most likely to occur by a hydrogen-related process for low-copper-containing Al-Zn-Mg-Cu alloys in under-, peak- and over-aged tempers, and for high-copper alloys in under- and peak-aged tempers. For over-aged high-copper-containing alloys, cracking is most probably under anodic dissolution control. Future stress corrosion studies should focus on understanding the factors that control crack initiation, and insuring that the next generation of higher performance Al-Zn-Mg-Cu alloys has similar longer crack initiation times and crack propagation rates to those of the incumbent alloys in an over-aged condition where crack rates are less than 1 mm/month at a high stress intensity factor

New Insights into White-Light Flare Emission from Radiative-Hydrodynamic Modeling of a Chromospheric Condensation

(abridged) The heating mechanism at high densities during M dwarf flares is poorly understood. Spectra of M dwarf flares in the optical and near-ultraviolet wavelength regimes have revealed three continuum components during the impulsive phase: 1) an energetically dominant blackbody component with a color temperature of T $\sim$ 10,000 K in the blue-optical, 2) a smaller amount of Balmer continuum emission in the near-ultraviolet at lambda $<$ 3646 Angstroms and 3) an apparent pseudo-continuum of blended high-order Balmer lines. These properties are not reproduced by models that employ a typical "solar-type" flare heating level in nonthermal electrons, and therefore our understanding of these spectra is limited to a phenomenological interpretation. We present a new 1D radiative-hydrodynamic model of an M dwarf flare from precipitating nonthermal electrons with a large energy flux of $10^{13}$ erg cm$^{-2}$ s$^{-1}$. The simulation produces bright continuum emission from a dense, hot chromospheric condensation. For the first time, the observed color temperature and Balmer jump ratio are produced self-consistently in a radiative-hydrodynamic flare model. We find that a T $\sim$ 10,000 K blackbody-like continuum component and a small Balmer jump ratio result from optically thick Balmer and Paschen recombination radiation, and thus the properties of the flux spectrum are caused by blue light escaping over a larger physical depth range compared to red and near-ultraviolet light. To model the near-ultraviolet pseudo-continuum previously attributed to overlapping Balmer lines, we include the extra Balmer continuum opacity from Landau-Zener transitions that result from merged, high order energy levels of hydrogen in a dense, partially ionized atmosphere. This reveals a new diagnostic of ambient charge density in the densest regions of the atmosphere that are heated during dMe and solar flares.Comment: 50 pages, 2 tables, 13 figures. Accepted for publication in the Solar Physics Topical Issue, "Solar and Stellar Flares". Version 2 (June 22, 2015): updated to include comments by Guest Editor. The final publication is available at Springer via http://dx.doi.org/10.1007/s11207-015-0708-

A randomised controlled trial of acceptance and commitment therapy plus usual care compared to usual care alone for improving psychological health in people with motor neuron disease (COMMEND): study protocol

Background Motor neuron disease (MND) is a rapidly progressive, fatal neurodegenerative disease that predominantly affects motor neurons from the motor cortex to the spinal cord and causes progressive wasting and weakening of bulbar, limb, abdominal and thoracic muscles. Prognosis is poor and median survival is 2–3 years following symptom onset. Psychological distress is relatively common in people living with MND. However, formal psychotherapy is not routinely part of standard care within MND Care Centres/clinics in the UK, and clear evidence-based guidance on improving the psychological health of people living with MND is lacking. Previous research suggests that Acceptance and Commitment Therapy (ACT) may be particularly suitable for people living with MND and may help improve their psychological health. Aims To assess the clinical and cost-effectiveness of ACT modified for MND plus usual multidisciplinary care (UC) in comparison to UC alone for improving psychological health in people living with MND. Methods The COMMEND trial is a multi-centre, assessor-blind, parallel, two-arm RCT with a 10-month internal pilot phase. 188 individuals aged ≥ 18 years with a diagnosis of definite, laboratory-supported probable, clinically probable, or possible familial or sporadic amyotrophic lateral sclerosis, and additionally the progressive muscular atrophy and primary lateral sclerosis variants, will be recruited from approximately 14 UK-based MND Care Centres/clinics and via self-referral. Participants will be randomly allocated to receive up to eight 1:1 sessions of ACT plus UC or UC alone by an online randomisation system. Participants will complete outcome measures at baseline and at 6- and 9-months post-randomisation. The primary outcome will be quality of life at six months. Secondary outcomes will include depression, anxiety, psychological flexibility, health-related quality of life, adverse events, ALS functioning, survival at nine months, satisfaction with therapy, resource use and quality-adjusted life years. Primary analyses will be by intention to treat and data will be analysed using multi-level modelling. Discussion This trial will provide definitive evidence on the clinical and cost-effectiveness of ACT plus UC in comparison to UC alone for improving psychological health in people living with MND