756 research outputs found

    Optimization of Roadway Electrification Integrating Wireless Power Transfer: TechnoEconomic Assessment and Lifecycle Analysis

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    Electric vehicles are the main technology currently being pursued to reduce dependence on fossil fuels in the transportation sector. These vehicles provide both reduced greenhouse gas emissions and decreased operating costs when compared to conventional internal combustion vehicles, while providing the flexibility to use both renewable and fossil energy. However, these vehicles have seen limited consumer adoption due to their large purchase prices and limited driving range. Both purchase price and driving range are related to the large onboard battery systems required for electric vehicle travel. One solution to decrease dependence on large battery systems has focused on charging vehicles in-motion using wireless power transfer. In-motion charging of electric vehicles would allow for longer range travel with smaller onboard battery systems which would lead to cheaper vehicles and, in turn, greater consumer acceptance. Wireless power transfer is commonly used for small electronics (i.e. cell phones), but has seen limited use on large scale projects. Therefore, limited work has been done to understand the feasibility of in-motion charging of electric vehicles using wireless power transfer. The goal of this thesis is to better understand the economic feasibility, environmental benefit, and infrastructure requirements of a wirelessly charged electric vehicle fleet for transportation in the United States

    Galectins and their involvement in ocular disease and development

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    Galectins are carbohydrate binding proteins with high affinity to Ăź-galactoside containing glycoconjugates. Understanding of the functions of galectins has grown steadily over the past decade, as a result of substantial advancements in the field of glycobiology. Galectins have been shown to be versatile molecules that participate in a range of important biological systems, including inflammation, neovascularisation and fibrosis. These processes are of particular importance in ocular tissues, where a major theme of recent research has been to divert diseases away from pathways which result in loss of function into pathways of repair and regeneration. This review summarises our current understanding galectins in the context important ocular diseases, followed by an update on current clinical studies and future directions

    Feasibility of wireless power transfer for electrification of transportation: Techno-economics and life cycle assessment

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    Integration of wireless power transfer (WPT) systems in roadways and vehicles represents a promising alternative to traditional internal combustion transportation systems. The economic feasibility and environmental impact of WPT applied to the transportation system is evaluated through the development of engineering system models. For a 20% penetration of the WPT technology in vehicles, results show a 20% reduction in air pollutants, 10% reduction in energy use and CO2 emissions and a societal level payback (defined as total cost of ownership savings compared to a traditional vehicle equal to roadway infrastructure) of 3 years. The modeled system covers 86% of all traffic in the US, impacts 40% of all roadways and shifts $180 billion per year from oil production to jobs in local power generation and development, construction, and maintenance of electrified roadways and new electric vehicles. Results on model sensitivity to energy prices, payback as a function of penetration, and trucking vs light duty use are presented

    Strain Specific Responses in a Microbead Rat Model of Experimental Glaucoma

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    Purpose: A major challenge in glaucoma research is the lack of reproducible animal models of RGC and optic nerve damage, the characteristic features of this condition. We therefore examined the glaucomatous responses of two different rat strains, the Brown Norway (BN) and Lister Hooded (LH) rats, to high intraocular pressure (IOP) induced by injection of magnetic beads into the anterior chamber. Methods: Magnetic microsphere suspensions (20 µl of 5–20 mg/ml) were injected into the anterior chamber of BN (n = 9) or LH (N = 15) rats. Animals from each strain were divided into three groups, each receiving a different dose of microspheres. IOP was measured over 4 weeks using a rebound tonometer. Retinal ganglion cell (RGC) damage and function were assessed using scotopic electroretinograms (ERGs), retinal flatmounts and optic nerve histology. ANOVA and Student’s t-tests were used to analyse the data. Results: A significant elevation in IOP was observed in BN rats receiving injections of 20 mg (37.18 ± 12.28 mmHg) or 10 mg microspheres/ml (36.95 ± 13.63 mmHg) when compared with controls (19.63 ± 4.29 mmHg) (p < .001) over 2 weeks. This correlated with a significant impairment of RGC function, as determined by scotopic ERG (p < .001), reduction in axon number (p < .05) and lower RGC density (P < .05) in animals receiving 20 mg or 10 mg microspheres/ml as compared with controls. LH rats receiving similar microsphere doses showed reduced scotopic ERG function (p < .001) after 2 weeks. No changes in IOP was seen in this strain, although a reduction in axon density was observed in optic nerve cross-sections (p < .05). Initial changes in IOP and ERG responses observed in BN rats remained unchanged for a duration of 7 weeks. In LH animals, ERG responses were decreased at 1–2 weeks and returned to control levels after 5 weeks. Conclusions: Although this model was easily reproducible in BN rats, the phenotype of injury observed in LH rats was very different from that observed in BN animals. We suggest that differences in the glaucomatous response observed in these two strains may be ascribed to anatomical and physiological differences and merits further investigation

    Prospects for the application of MĂĽller glia and their derivatives in retinal regenerative therapies

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    Neural cell death is the main feature of all retinal degenerative disorders that lead to blindness. Despite therapeutic advances, progression of retinal disease cannot always be prevented, and once neuronal cell damage occurs, visual loss cannot be reversed. Recent research in the stem cell field, and the identification of MĂĽller glia with stem cell characteristics in the human eye, have provided hope for the use of these cells in retinal therapies to restore vision. MĂĽller glial cells, which are the major structural cells of the retina, play a very important role in retinal homeostasis during health and disease. They are responsible for the spontaneous retinal regeneration observed in zebrafish and lower vertebrates during early postnatal life, and despite the presence of MĂĽller glia with stem cell characteristics in the adult mammalian retina, there is no evidence that they promote regeneration in humans. Like many other stem cells and neurons derived from pluripotent stem cells, MĂĽller glia with stem cell potential do not differentiate into retinal neurons or integrate into the retina when transplanted into the vitreous of experimental animals with retinal degeneration. However, despite their lack of integration, grafted MĂĽller glia have been shown to induce partial restoration of visual function in spontaneous or induced experimental models of photoreceptor or retinal ganglion cell damage. This improvement in visual function observed after MĂĽller cell transplantation has been ascribed to the release of neuroprotective factors that promote the repair and survival of damaged neurons. Due to the development and availability of pluripotent stem cell lines for therapeutic uses, derivation of MĂĽller cells from retinal organoids formed by iPSC and ESC has provided more realistic prospects for the application of these cells to retinal therapies. Several opportunities for research in the regenerative field have also been unlocked in recent years due to a better understanding of the genomic and proteomic profiles of the developing and regenerating retina in zebrafish, providing the basis for further studies of the human retina. In addition, the increased interest on the nature and function of cellular organelle release and the characterization of molecular components of exosomes released by MĂĽller glia, may help us to design new approaches that could be applied to the development of more effective treatments for retinal degenerative diseases

    Time to surgery for open hand injuries and the risk of surgical site infection: a prospective multicentre cohort study

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    Whether delaying surgery increases the risk of infection in open hand injuries is an important but unresolved topic. This prospective cohort study included 983 consecutive adults with open hand injuries treated surgically over 1 year. The risk ratio (RR) for surgical site infection was estimated by logistic regression. The median time from injury to surgery was 20 hours (range 4–90). Forty-one patients (4%) developed an infection. The risk of infection was not affected by the time to surgery (adjusted risk ratio 1.0 [95% CI: 1.0 to 1.0]) or preoperative antibiotics (adjusted risk ratio 1.8 [95% CI: 0.2 to 13]), which were provided to 95% of patients. Skin loss increased the risk of infection (adjusted risk ratio 2.6 [95% CI: 1.3 to 5.0]). Delaying surgery for open hand injuries by 4 days does not appear to increase the risk of surgical site infection

    Size exclusion chromatography as a technique for the investigation of novel extracellular vesicles in cancer

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    Abstract: (1) Background: Cancer cells release extracellular vesicles that are a rich target for biomarker discovery and provide a promising mechanism for liquid biopsy. SEC is an increasingly popular technique which has been rediscovered for the purposes of EV isolation and purification from diverse biofluids. (2) Methods: A review was undertaken to identify all papers which described size exclusion as their primary EV isolation method in cancer research. (3) Results: 37 papers were identified and discussed which showcases the breadth of applications that EVs can be utilised, from proteomics, to RNA, and through to functionality. A range of different methods are highlighted, with Sepharose-based techniques predominating. (4) Conclusions: EVs isolated using SEC are able to identify cancer cells, highlight active pathways in tumourigenesis, clinically distinguish cohorts and remain functionally active for further experiments

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    QM/MM simulations as an assay for carbapenemase activity in class A β-lactamases

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    Carbapenemases are distinguished from carbapenem-inhibited β-lactamases with a protocol involving QM/MM free energy simulations of acyl–enzyme deacylation, requiring only the enzyme 3D structure as input.</p

    QM/MM Simulations Reveal the Determinants of Carbapenemase Activity in Class A β-lactamases

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    [Image: see text] β-lactam antibiotic resistance in Gram-negative bacteria, primarily caused by β-lactamase enzymes that hydrolyze the β-lactam ring, has become a serious clinical problem. Carbapenems were formerly considered “last resort” antibiotics because they escaped breakdown by most β-lactamases, due to slow deacylation of the acyl-enzyme intermediate. However, an increasing number of Gram-negative bacteria now produce β-lactamases with carbapenemase activity: these efficiently hydrolyze the carbapenem β-lactam ring, severely limiting the treatment of some bacterial infections. Here, we use quantum mechanics/molecular mechanics (QM/MM) simulations of the deacylation reactions of acyl-enzyme complexes of eight β-lactamases of class A (the most widely distributed β-lactamase group) with the carbapenem meropenem to investigate differences between those inhibited by carbapenems (TEM-1, SHV-1, BlaC, and CTX-M-16) and those that hydrolyze them (SFC-1, KPC-2, NMC-A, and SME-1). QM/MM molecular dynamics simulations confirm the two enzyme groups to differ in the preferred acyl-enzyme orientation: carbapenem-inhibited enzymes favor hydrogen bonding of the carbapenem hydroxyethyl group to deacylating water (DW). QM/MM simulations of deacylation give activation free energies in good agreement with experimental hydrolysis rates, correctly distinguishing carbapenemases. For the carbapenem-inhibited enzymes, free energies for deacylation are significantly higher than for the carbapenemases, even when the hydroxyethyl group was restrained to prevent interaction with the DW. Analysis of these simulations, and additional simulations of mutant enzymes, shows how factors including the hydroxyethyl orientation, the active site volume, and architecture (conformations of Asn170 and Asn132; organization of the oxyanion hole; and the Cys69-Cys238 disulfide bond) collectively determine catalytic efficiency toward carbapenems
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