Cataract surgery and quality of life implications

Cataract surgery in the developed world has undergone a revolution over the last 20 years. An operation which used to require a stay in hospital and long visual rehabilitation is now a quick day-case procedure with immediate benefits. As with any surgery there is an associated morbidity, but there is now the potential to provide cataract surgery at an earlier stage of cataract maturation and save patients from a period of severe visual impairment. This article reviews the new techniques available to measure the impact that cataracts have not only on a patient’s visual acuity but also their general physical health, function, cognition, and emotional well-being. New research is described that takes into account these more holistic tests and how they can be used to judge the best time to refer and operate on a patient with cataracts

Mitochondrial DNA changes in pedunculopontine cholinergic neurons in Parkinson’s disease

In Parkinson’s disease (PD), mitochondrial dysfunction associates with nigral dopaminergic neuronal loss. Cholinergic neuronal loss co-occurs, particularly within a brainstem structure, the pedunculopontine nucleus (PPN). We isolated single cholinergic neurons from post-mortem PPNs of aged controls and PD patients. Mitochondrial DNA (mtDNA) copy number and mtDNA deletions were increased significantly in PD patients compared to controls. Furthermore, compared to controls the PD patients had significantly more PPN cholinergic neurons containing mtDNA deletion levels exceeding 60%, a level associated with deleterious effects on oxidative phosphorylation. The current results differ from studies reporting mtDNA depletion in nigral dopaminergic neurons of PD patients

Tracking circadian rhythms of bone mineral deposition in murine calvarial organ cultures

Osteoblasts, which orchestrate the deposition of small apatite crystals through the expression of nucleating proteins, have been shown to also express clock genes associated with the circadian signaling pathway. We hypothesized that protein‐mediated bone mineralization may be linked to circadian oscillator mechanisms functioning in peripheral bone tissue. In this study, Per1 expression in ex vivo neonatal murine calvaria organ cultures was monitored for 6 days using a Per1 ‐ luciferase transgene as a bioluminescent indicator of clock function. Fluctuations in Per1 expression had a period of 25 ± 4 hours ( n  = 14) with early expression at CT09:59 ± 03:37 (CT = circadian time). We also established the kinetics of mineral deposition in developing bone by using noninvasive Raman microscopy to track mineral accumulation in calvarial tissue. The content and quality of newly deposited mineral was continually examined at the interparietal bone/fontanel boundary for a period of 6 days with 1‐hour temporal resolution. Using this approach, mineralization over time exhibited bursts of mineral deposition followed by little or no deposition, which was recurrent with a periodicity of 26.8 ± 9.6 hours. As many as six near‐daily mineralization events were observed in the calvaria before deposition ceased. Earliest mineralization events occurred at CT16:51 ± 03:45, which is 6 hours behind Per1 expression. These findings are consistent with the hypothesis that mineralization in developing bone tissue is regulated by a local circadian oscillator mechanism.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99084/1/jbmr1924.pd

Restoration of Strength in Polyamide Woven Glass Fiber Organosheets by Hot Pressing

Thermoplastic composite organosheets (OSs) are increasingly recognized as a viable solution for automotive and aerospace structures, offering a range of benefits including cost-effectiveness through high-rate production, lightweight design, impact resistance, formability, and recyclability. This study examines the impact response, post-impact strength evaluation, and hot-pressing repair effectiveness of woven glass fiber nylon composite OSs across varying impact energy levels. Experimental investigations involved subjecting composite specimens to impact at varying energy levels using a drop-tower test rig, followed by compression-after-impact (CAI) tests. The results underscore the exceptional damage tolerance and improved residual compressive strength of the OSs compared to traditional thermoset composites. This enhancement was primarily attributed to the matrix’s ductility, which mitigated transverse crack propagation and significantly increased the amount of absorbed energy. To mitigate impact-induced damage, a localized hot-pressing repair approach was developed. This allowed to restore the post-impact strength of the OSs to pristine levels for impact energies below 40 J and by 83.6% for higher impact energies, when OS perforation was observed. The measured levels of post-repair strength demonstrate a successful restoration of OS strength over a wide range of impact energies, and despite limitations in achieving complete strength recovery above 40 J, hot-pressing repair emerges as a promising strategy for ensuring the longevity of thermoplastic composites through repairability

Obtaining material identification with cosmic ray radiography

The passage of muons through matter is mostly affected by their Coulomb interactions with electrons and nuclei. The muon interactions with electrons lead to continuous energy loss and stopping of muons, while their scattering off nuclei lead to angular 'diffusion'. By measuring both the number of stopped muons and angular changes in muon trajectories we can estimate density and identify materials. Here we demonstrate the material identification using data taken at Los Alamos with the Mini Muon Tracker.Comment: 10 pages, 9 figures, Accepted to AIP Advance

Antemortem diagnosis of asbestosis by screening chest radiograph correlated with postmortem histologic features of asbestosis: a study of 273 cases

BACKGROUND: Accuracy in the clinical diagnosis of asbestosis has significant implications for the future health of affected patients as well as serious medicolegal implications for both patients and asbestos-associated industries. The radiographic gold-standard for diagnosis of asbestosis has been the plain chest radiograph, and in many asbestosis-screening clinics, chest radiograph abnormalities in conjunction with a history of asbestos exposure have been the mainstay of diagnosis. No studies have yet compared the antemortem chest radiographic diagnosis of asbestosis with the subsequent presence of pulmonary fibrosis and lung tissue ferruginous bodies at autopsy. METHODS: Records were reviewed from 273 autopsies performed to investigate asbestosis over an 11-year period. Accrued data included age and gender as well as the presence or absence of the following: occupational exposure to asbestos, antemortem clinical diagnosis of asbestosis by chest radiograph, fibrous pleural plaques, peribronchiolar or interstitial pulmonary fibrosis, ferruginous bodies in histologic sections of lung tissue, and ferruginous bodies in digested lung tissue. RESULTS: 242 cases with the antemortem radiographic diagnosis of asbestosis (study group) were identified. 31 additional autopsies had been requested based on history of asbestos exposure without radiographic documentation of asbestosis (control group). Comparison of the two groups showed a statistically significant increase in the association of chest radiograph-diagnosed asbestosis and the presence at autopsy of pleural plaques (p = 0.0109), peribronchiolar or interstitial pulmonary fibrosis (p = 0.0472), and histologically-diagnostic asbestosis (p = 0.0021). At autopsy, histologically-diagnostic asbestosis was confirmed in only 90 of the 243 study group cases. Comparison of individual parameters within the 242 study group cases showed a statistically significant correlation between the presence of fibrous pleural plaques and histologically-proven pulmonary fibrosis (p = 0.0025) as well as the subsequent histologic diagnosis of asbestosis (p < 0.0001). CONCLUSION: Clinical diagnosis of asbestosis by screening chest radiograph is more predictive of the postmortem presence of fibrous pleural plaques, pulmonary fibrosis, and histologically-proven asbestosis than is occupational exposure history alone. However, chest radiograph-based diagnosis of asbestosis significantly overpredicts the subsequent histologic diagnosis of asbestosis