2,321 research outputs found
Refractive change following pseudophakic vitrectomy: a retrospective review
Background
To assess the occurrence and magnitude of refractive change in pseudophakic eyes undergoing 20 gauge pars plana vitrectomy without scleral buckling and to investigate possible aetiological factors.
Methods
Retrospective case note review of 87 pseudophakic eyes undergoing 20 gauge pars plana vitrectomy for a variety of vitreo-retinal conditions over a three-year period. Anterior chamber depth (ACD) was measured before and after vitrectomy surgery in 32 eyes. Forty-three pseudophakic fellow eyes were used as controls.
Results
Eighty-seven eyes (84 patients) were included in the study. Mean spherical equivalent refraction prior to vitrectomy was -0.20 dioptres, which changed to a mean of -0.65 dioptres postoperatively (standard deviation of refractive change 0.59, range-2.13 to 0.75 dioptres) (p < 0.001). Sixty-one of the 87(70%) eyes experienced a myopic shift and 45(52%) eyes had a myopic shift of -0.5 dioptres or more. Mean fellow eye refraction was -0.19 dioptres preoperatively and -0.17 dioptres postoperatively (p = 0.14)(n = 37) Mean ACD preoperatively was 3.29 mm and postoperatively 3.27 mm (p = 0.53) (n = 32) and there was no significant change in ACD with tamponade use. Regression analysis revealed no statistically significant association between changes in anterior chamber depth, as well as a wide variety of other pre-, intra and postoperative factors examined, and the refractive change observed.
Conclusion
Significant refractive changes occur in some pseudophakic patients undergoing 20 g pars plana vitrectomy. The mean change observed was a small myopic shift but the range was large. The aetiology of the refractive change is uncertain
Memory T Cell Responses Targeting the SARS Coronavirus Persist up to 11 Years Post-Infection
10.1016/j.vaccine.2016.02.063Vaccine34172008–201
Medical Evaluation and Triage of the Agitated Patient: Consensus Statement of the American Association for Emergency Psychiatry Project BETA Medical Evaluation Workgroup
Numerous medical and psychiatric conditions can cause agitation; some of these causes are life threatening. It is important to be able to differentiate between medical and nonmedical causes of agitation so that patients can receive appropriate and timely treatment. This article aims to educate all clinicians in nonmedical settings, such as mental health clinics, and medical settings on the differing levels of severity in agitation, basic triage, use of de-escalation, and factors, symptoms, and signs in determining whether a medical etiology is likely. Lastly, this article focuses on the medical workup of agitation when a medical etiology is suspected or when etiology is unclear
Verbal De-escalation of the Agitated Patient: Consensus Statement of the American Association for Emergency Psychiatry Project BETA De-escalation Workgroup
Agitation is an acute behavioral emergency requiring immediate intervention. Traditional methods of treating agitated patients, ie, routine restraints and involuntary medication, have been replaced with a much greater emphasis on a noncoercive approach. Experienced practitioners have found that if such interventions are undertaken with genuine commitment, successful outcomes can occur far more often than previously thought possible. In the new paradigm, a 3-step approach is used. First, the patient is verbally engaged; then a collaborative relationship is established; and, finally, the patient is verbally de-escalated out of the agitated state. Verbal de-escalation is usually the key to engaging the patient and helping him become an active partner in his evaluation and treatment; although, we also recognize that in some cases nonverbal approaches, such as voluntary medication and environment planning, are also important. When working with an agitated patient, there are 4 main objectives: (1) ensure the safety of the patient, staff, and others in the area; (2) help the patient manage his emotions and distress and maintain or regain control of his behavior; (3) avoid the use of restraint when at all possible; and (4) avoid coercive interventions that escalate agitation. The authors detail the proper foundations for appropriate training for de-escalation and provide intervention guidelines, using the “10 domains of de-escalation.
Visualisation and performance evaluation of biodiesel/methane co-combustion in a swirl-stabilised gas turbine combustor
While dual fuel firing of power generation combustion systems can improve the fuel flexibility of such systems, several studies on compression ignition engines have also shown a positive impact on NOX and PM emissions. Previous multiphase fuel combustion studies for combustion turbines are limited, thus the present study addresses that gap by fuelling a model swirl stabilised gas turbine combustor with a blend of waste cooking oil-derived biodiesel and methane. Methane was increasingly injected into swirling combustion air flow while simultaneously reducing the biodiesel spray flowrate across a pressure atomiser, thus maintaining an overall equivalence ratio of 0.7 while delivering a thermal power output of 15 kW in all cases, except for flame stability range trials. Direct flame imaging, CH* and C2* chemiluminescence imaging, post combustion emissions as well as stability performance of the flames were evaluated. NOX emissions were found to decrease by 29% and unburnt hydrocarbons increased by 10% as the fraction of methane in fuel mix increased to 30%. Further, flame images suggest increased wrinkling and perturbing of the flame front as gas fraction of the biodiesel/methane flame increases. However, the temporal variation of integral intensity of CH* and C2* species chemiluminescence point to at least an 8% improvement in flame stability when 30% of flame heat output is supplied by methane compared to neat biodiesel burn. Also, it was found that flame stability limits reduce as methane partly replaces biodiesel in the flame
All-sky convolution for polarimetry experiments
We discuss all-sky convolution of the instrument beam with the sky signal in
polarimetry experiments, such as the Planck mission which will map the
temperature anisotropy and polarization of the cosmic microwave background
(CMB). To account properly for stray light (from e.g. the galaxy, sun, and
planets) in the far side-lobes of such an experiment, it is necessary to
perform the beam convolution over the full sky. We discuss this process in
multipole space for an arbitrary beam response, fully including the effects of
beam asymmetry and cross-polarization. The form of the convolution in multipole
space is such that the Wandelt-Gorski fast technique for all-sky convolution of
scalar signals (e.g. temperature) can be applied with little modification. We
further show that for the special case of a pure co-polarized, axisymmetric
beam the effect of the convolution can be described by spin-weighted window
functions. In the limits of a small angle beam and large Legendre multipoles,
the spin-weight 2 window function for the linear polarization reduces to the
usual scalar window function used in previous analyses of beam effects in CMB
polarimetry experiments. While we focus on the example of polarimetry
experiments in the context of CMB studies, we emphasise that the formalism we
develop is applicable to anisotropic filtering of arbitrary tensor fields on
the sphere.Comment: 8 pages, 1 figure; Minor changes to match version accepted by Phys.
Rev.
VEGF\u3csub\u3e164\u3c/sub\u3e-Mediated Inflammation is Required for Pathological, but Not Physiological, Ischemia-Induced Retinal Neovascularization
Hypoxia-induced VEGF governs both physiological retinal vascular development and pathological retinal neovascularization. In the current paper, the mechanisms of physiological and pathological neovascularization are compared and contrasted. During pathological neovascularization, both the absolute and relative expression levels for VEGF164 increased to a greater degree than during physiological neovascularization. Furthermore, extensive leukocyte adhesion was observed at the leading edge of pathological, but not physiological, neovascularization. When a VEGF164-specific neutralizing aptamer was administered, it potently suppressed the leukocyte adhesion and pathological neovascularization, whereas it had little or no effect on physiological neovascularization. In parallel experiments, genetically altered VEGF164-deficient (VEGF120/188) mice exhibited no difference in physiological neovascularization when compared with wild-type (VEGF+/+) controls. In contrast, administration of a VEGFR-1/Fc fusion protein, which blocks all VEGF isoforms, led to significant suppression of both pathological and physiological neovascularization. In addition, the targeted inactivation of monocyte lineage cells with clodronate-liposomes led to the suppression of pathological neovascularization. Conversely, the blockade of T lymphocyte–mediated immune responses with an anti-CD2 antibody exacerbated pathological neovascularization. These data highlight important molecular and cellular differences between physiological and pathological retinal neovascularization. During pathological neovascularization, VEGF164 selectively induces inflammation and cellular immunity. These processes provide positive and negative angiogenic regulation, respectively. Together, new therapeutic approaches for selectively targeting pathological, but not physiological, retinal neovascularization are outlined
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