The fovea of the human retina, a specialization for acute and color vision, features a high concentration of cone photoreceptors. A pit on the inner retinal aspect is created by the centrifugal migration of post-receptoral neurons. Foveal cells are specified early in fetal life, but the fovea reaches its final configuration postnatally.
View Article and Find Full Text PDFThe post-heat mechanical property is one of the important indices for the fire-resistance evaluation of fiber-reinforced polymers. At present, the primary approach to improving the post-heat mechanical property of a material involves incorporating inorganic fillers; yet, the enhancement is limited, and is accompanied by a reduction in room-temperature performance and processability. This study prepares glass-fiber-reinforced composites with elevated mechanical properties after heat through utilizing two variants of epoxy resins modified with polysiloxane, phenolic resin, kaolin, and graphite.
View Article and Find Full Text PDFα-Hydroxy ketones are a class of vital organic skeletons that generally exist in a variety of natural products and high-value chemicals. However, the traditional synthetic route for their production involves toxic Hg salts and corrosive HSO as catalysts, resulting in harsh conditions and the undesired side reaction of Meyer-Schuster rearrangement. In this study, CO-promoted hydration of propargylic alcohols was achieved for the synthesis of various α-hydroxy ketones.
View Article and Find Full Text PDFIntroduction: Age related macular degeneration (AMD) causes legal blindness worldwide, with few therapeutic targets in early disease and no treatments for 80% of cases. Extracellular deposits, including drusen and subretinal drusenoid deposits (SDD; also called reticular pseudodrusen), disrupt cone and rod photoreceptor functions and strongly confer risk for advanced disease. Due to the differential cholesterol composition of drusen and SDD, lipid transfer and cycling between photoreceptors and support cells are candidate dysregulated pathways leading to deposit formation.
View Article and Find Full Text PDFMitochondria are candidate reflectivity signal sources in optical coherence tomography (OCT) retinal imaging. Here, we use deep-learning-assisted volume electron microscopy of human retina and imaging to map mitochondria networks in the outer plexiform layer (OPL), where photoreceptors synapse with second-order interneurons. We observed alternating layers of high and low mitochondrial abundance in the anatomical OPL and adjacent inner nuclear layer (INL).
View Article and Find Full Text PDFIn filament wound composites, fiber bundles cross each other and form an undulating architecture, which may significantly affect the mechanical behavior of composites. In this study, the tensile mechanical behavior of filament wound laminates was studied experimentally and numerically, and the influences of the bundle thickness and winding angle on the mechanical behavior of the filament wound plates were also explored. In the experiments, tensile tests were carried out on filament wound plates and laminated plates.
View Article and Find Full Text PDFThis paper presents an easy and low-cost flame treatment method to improve the bonding performance of GF/EP (Glass Fiber-Reinforced Epoxy) pultrusion plates, which are using widely for large size wind blades. In order to explore the effect of flame treatment on the bonding performance of the precast GF/EP pultruded sheet vs. the infusion plate, the GF/EP pultruded sheets were treated with different flame treatment cycles and were embedded in the fiber fabrics during the vacuum-assisted resin infusion process (VARI).
View Article and Find Full Text PDFPurpose: The purpose of this study was to investigate histologic autofluorescence lifetimes and spectra of retinal pigment epithelium (RPE) on the transition from normal aging to RPE activation and migration in age-related macular degeneration (AMD).
Methods: Autofluorescence lifetimes and spectra of 9 donor eyes were analyzed in cryosections by means of 2-photon excited fluorescence at 960 nm. Spectra were detected at 483 to 665 nm.
Thin-ply composite failure modes also significantly differ from conventional ply composite failure modes, with the final failure mechanism switching from irregular progressive failure to direct fracture characterized by a uniform fracture with the reduction of the ply thickness. When open holes and bolt joints are involved, thin-ply-laminated composites exhibit more complex stress states, damage evolution, and failure modes. Compared to the experimental study of thin-ply-laminated composite-bolted joints, there are few reports about numerical analysis.
View Article and Find Full Text PDFUnderstanding the molecular composition of ocular tissues and fluids could inform new approaches to prevalent causes of blindness. Subretinal fluid accumulating between the photoreceptor outer segments and retinal pigment epithelium (RPE) is potentially a rich source of proteins and lipids normally cycling among outer retinal cells and choroid. Herein, intact post-translationally modified proteins (proteoforms) were extracted from subretinal fluids of five patients with rhegmatogenous retinal detachment (RRD), analyzed by tandem mass spectrometry, and compared to published data on these same proteins as synthesized by other organs.
View Article and Find Full Text PDFThis paper reported the tensile failure strengths and damage procedure of composite laminate manufactured from the toughened-epoxy T800 prepreg at multi-scale levels. According to the exterior and interior distinction of each layer in laminate, the macro/mesoscale representative volume element (macro-RVE, meso-RVE) was first constructed, respectively. Then the micro-scale representative volume element (micro-RVE) with a hexagonal fiber-packed pattern in the interior zone of each layer in the laminate was finally determined on the principle of the same fiber volume fraction between the composite laminate and multi-scale RVEs.
View Article and Find Full Text PDFPurpose: Melanotic cells with large spherical melanosomes, thought to originate from retinal pigment epithelium (RPE), are found in eyes with neovascular age-related macular degeneration (nvAMD). To generate hypotheses about RPE participation in fibrosis, we correlate histology to clinical imaging in an eye with prominent black pigment in fibrotic scar secondary to nvAMD.
Methods: Macular findings in a white woman with untreated inactive subretinal fibrosis due to nvAMD in her right eye were documented over 9 years with color fundus photography (CFP), fundus autofluorescence (FAF) imaging, and optical coherence tomography (OCT).
Purpose: By optical coherence tomography (OCT) imaging, hyperreflective foci (HRF) indicate progression risk for advanced age-related macular degeneration (AMD) and are in part attributable to ectopic retinal pigment epithelium (RPE). We hypothesized that ectopic RPE are molecularly distinct from in-layer cells and that their cross-retinal course follows Müller glia.
Methods: In clinical OCT (61 eyes, 44 patients with AMD, 79.
Materials (Basel)
February 2021
Compared with standard-ply composites, thin-ply composites exhibit a superior mechanical performance under various operating conditions due to their positive size effects. Thin-ply laminate failure modes, including matrix initial damage (MID), matrix failure (MF), and fiber failure (FF), have been distinguished through a systematic acoustic emission (AE) signals analysis combined with scanning electron microscopy (SEM). First, the characteristic frequencies of various failure modes are identified based on unidirectional laminates ([90] and [0] ).
View Article and Find Full Text PDFAutophagy and lysosomal function are important for protein homeostasis and their dysfunction have been associated with Alzheimer's disease (AD). Increased immunoreactivities of an important lysosomal protease, cathepsin D (Cat D), are evident in amyloid plaques and neurons in patients with AD. This study tests the hypothesis that deleting one allele of the cathepsin D gene (Ctsd) impacts cerebral β-amyloidosis in amyloid-β precursor protein (APP)sw/PS1dE9 (APP/PS1) double transgenic mice.
View Article and Find Full Text PDFIsoprenoids and prenylated proteins have been implicated in the pathophysiology of Alzheimer disease (AD), including amyloid-β precursor protein metabolism, Tau phosphorylation, synaptic plasticity, and neuroinflammation. However, little is known about the relative importance of the two protein prenyltransferases, farnesyltransferase (FT) and geranylgeranyltransferase-1 (GGT), in the pathogenesis of AD. In this study, we defined the impact of deleting one copy of FT or GGT on the development of amyloid-β (Aβ)-associated neuropathology and learning/memory impairments in APPPS1 double transgenic mice, a well established model of AD.
View Article and Find Full Text PDFTwo major isoprenoids, farnesyl pyrophosphate and geranylgeranyl pyrophosphate, serve as lipid donors for the posttranslational modification (known as prenylation) of proteins that possess a characteristic C-terminal motif. The prenylation reaction is catalyzed by prenyltransferases. The lipid prenyl group facilitates to anchor the proteins in cell membranes and mediates protein-protein interactions.
View Article and Find Full Text PDFWe evaluated the therapeutic efficacy of combined treatment of Aβ-immunization with simvastatin in an Alzheimer mouse model at age 22 months. DNA prime-adenovirus boost immunization induced modest anti-Aβ titers and simvastatin increased the seropositive rate. Aβ-KLH was additionally administered to boost the titers.
View Article and Find Full Text PDFTo date there is no effective therapy for Alzheimer disease (AD). High levels of circulating high density lipoprotein (HDL) and its main protein, apolipoprotein A-I (apoA-I), reduce the risk of cardiovascular disease. Clinical studies show that plasma HDL cholesterol and apoA-I levels are low in patients with AD.
View Article and Find Full Text PDFStatins are widely used to lower cholesterol levels by inhibiting cholesterol biosynthesis. Some evidence has indicated that statins might have therapeutic and preventive benefits for Alzheimer's disease (AD). We and others also have shown the beneficial effect of statin treatment in reversing learning and memory deficits in animal models of AD.
View Article and Find Full Text PDFRecent evidence indicates that inflammation may significantly contribute to the pathogenesis of Alzheimer's disease (AD). Since the apo A-I mimetic peptide D-4F has been shown to inhibit atherosclerotic lesion formation and regress already existing lesions (in the presence of pravastatin) and the peptide also decreases brain arteriole inflammation, we undertook a study to evaluate the efficacy of oral D-4F co-administered with pravastatin on cognitive function and amyloid beta (A beta) burden in the hippocampus of APPSwe-PS1 Delta E9 mice. Three groups of male mice were administered D-4F and pravastatin, Scrambled D-4F (ScD-4F, a control peptide) and pravastatin in drinking water, while drinking water alone served as control.
View Article and Find Full Text PDFDement Geriatr Cogn Disord
February 2009
Background: Conflicting results have been reported on the association of plasma total homocysteine (tHcy) and cholesterol levels in Alzheimer disease (AD). The objective of this study was to determine the relationship between cognitive performance and plasma levels of tHcy and its biological determinants folate and vitamin B(12), and lipids in clinically diagnosed AD patients.
Methods: A cross-sectional database review was performed on two separate groups of patients (n = 191).
Compelling evidence indicates that excess consumption of sugar-sweetened beverages plays an important role in the epidemic of obesity, a major risk factor for type 2 diabetes mellitus. Type 2 diabetes mellitus has been associated with a higher incidence of Alzheimer disease (AD). High fat diets promote AD-like pathology in mice.
View Article and Find Full Text PDFObjective: Normal aging is often associated with a decline in learning and memory functions. This decline is manifested to a much greater extent in Alzheimer's disease. Recent studies have indicated statins, a class of cholesterol-lowering drugs, as a potential therapy for Alzheimer's disease.
View Article and Find Full Text PDFEmerging evidence indicates that cholesterol metabolism affects the pathogenesis of Alzheimer's disease (AD). The LDL receptor (LDLR) is obligatory in maintaining cholesterol homeostasis in the periphery. To investigate the role of LDLR in the development of AD-like behavior and pathology, Tg2576 mice, a well-characterized transgenic mouse model of AD, with different genotypes of LDLR were generated.
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