241 research outputs found

    Computation of Madelung Energies for Ionic Crystals of Variable Stoichiometries and Mixed Valencies and their application in Lithium-ion battery voltage modelling

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    Electrostatic energy (Madelung energy) is a major constituent of the cohesive energy of ionic crystals. Several physicochemical properties of these materials depend on the response of their electrostatic energy to a variety of applied thermal, electrical and mechanical stresses. In the present study, a method has been developed based on Ewalds technique, to compute the electrostatic energy arising from ion-ion interactions in ionic crystals like LixMn2O4 with variable stoichiometries and mixed valencies. An interesting application of this method in computing the voltages of lithium ion batteries employing spinel cathodes is presented for the first time. The advantages of the present method of computation over existing methods are also discussed.Comment: 15 page

    Characteristics of non-fatal overdoses and associated risk factors in patients attending a specialist community-based substance misuse service

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    INTRODUCTION: There are concerns about rising drug-related deaths and the potential contribution of prescription analgesics. There is limited understanding regarding the role of prescription analgesics in non-fatal overdoses (NFODs), nor is there a good understanding of what factors are associated with more severe overdose. OBJECTIVES: To explore risk factors and characteristics of NFODs among people attending a specialist community-based substance misuse service. METHODS: After Caldicott approval, data on NFODs, in people attending the Tayside Substance Misuse Service (TSMS), were extracted from the Scottish Ambulance Service database, along with opioid replacement therapy (ORT) prescribing data. Statistical analysis was performed using R studio and Microsoft Excel. RESULTS: 557 people (78% [434/556] male, mean age ± standard deviation 38.4 ± 7.95) had an NFOD. Repeat NFODs were more likely in males compared to females (p < .0065). Males were more likely to be administered naloxone (OR = 1.94, 95% CI = 1.10–3.40, p < .02). NFODs at home were more likely to be moderate to severe (categorized by Glasgow Comma Scale [p < .02, OR = 4.95, 95% CI = 1.24–24.38]). Methadone (321/557, 57.63%), benzodiazepines (281/557, 50.45%) and heroin (244/557, 43.81%) were the commonest substances: prescribed methadone overdose was more likely than buprenorphine (p < .00001). Opioids and benzodiazepines were often taken together (275/557, 49.40%), with almost all gabapentinoid NFODs also involving opioids (60/61, 98.40%). CONCLUSIONS: Polysubstance use with opioids prescribed for ORT, such as methadone, is highly likely to be implicated in NFOD, with males being at the highest risk of severe and repeat NFOD. Future work should focus on strategies to further reduce NFODs

    Enhanced effect of liposome-encapsulated amikacin on Mycobacterium avium-M. intracellulare complex infection in beige mice

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    We examined the therapeutic effects of free and liposome-encapsulated amikacin on Mycobacterium avium-M. intracellulare complex infection by using the beige-mouse model of the disease. In the first series of studies, intravenous administration of four weekly doses of 5 mg of amikacin per kg encapsulated in large (approximately 0.4-μm diameter), unilamellar liposomes arrested the growth of M. avium-M. intracellulare complex organisms in the liver, as measured by CFU counts. M. avium-M. intracellulare complex levels in untreated animals and in those treated with the same dose of free amikacin increased by several orders of magnitude over 8 weeks. Liposome-encapsulated amikacin was also effective against M. avium-M. intracellulare complex organisms in the spleens and kidneys, reducing the CFU counts by about 1,000-fold compared with those of both untreated controls and free-drug-treated mice. In the lungs, a slight reduction in CFU was observed in the liposome-encapsulated-amikacin-treated group, but only at the 8-week point. Neither free nor liposome-encapsulated amikacin reduced the colony counts in the lymph nodes compared with those of control animals. Reductions in CFU in all organs greater than those caused by the liposome preparation could be achieved by intramuscular administration of free amikacin, but only at a 10-fold-higher dose given 6 days a week for 8 weeks. In the second series of studies, we investigated the effects of (i) doubling the dose of liposome-encapsulated amikacin and (ii) increasing the size of the liposomes and prolonging the treatment to five injections. Administration of 10 mg of amikacin per kg in liposomes 2 to 3 μm in diameter was more effective in the liver than 5 or 10 mg of amikacin per kg in liposomes 0.2 μm in diameter. A slight reduction in the CFU levels in the lungs was observed with the higher dose, irrespective of liposome size. Our results indicate that liposome-based delivery of amikacin enhances its anti-M. avium-M. intracellulare complex activity, particularly in the liver, spleen, and kidney, and may therefore improve the therapy of this disease

    A Genome-Wide Association Study Provides New Evidence That CACNA1C Gene is Associated With Diabetic Cataract

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    PURPOSE: Diabetic cataract is one of the major eye complications of diabetes. It was reported that cataract occurs two to five times more frequently in patients with diabetes compared with those with no diabetes. The purpose of this study was to identify genetic contributors of diabetic cataract based on a genome-wide association approach using a well-defined Scottish diabetic cohort. METHODS: We adapted linked e-health records to define diabetic cataract. A diabetic cataract case in this study was defined as a type 2 diabetic patient who has ever been recorded in the linked e-health records to have cataracts in both eyes or who had previous cataract extraction surgeries in at least one eye. A control in this study was defined as a type 2 diabetic individual who has never been diagnosed as cataract in the linked e-health records and had no history of cataract surgeries. A standard genome-wide association approach was applied. RESULTS: Overall, we have 2341 diabetic cataract cases and 2878 controls in the genetics of diabetes audit and research in Tayside Scotland (GoDARTS) dataset. We found that the P value of rs2283290 in the CACNA1C gene was 8.81 × 10(−10), which has reached genome-wide significance. We also identified that the blood calcium level was statistically different between diabetic cataract cases and controls. CONCLUSIONS: We identified supporting evidence that CACNA1C gene is associated with diabetic cataract. The role of calcium in the cataractogenesis needs to be reevaluated in future studies

    Light and myopia: from epidemiological studies to neurobiological mechanisms

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    Myopia is far beyond its inconvenience and represents a true, highly prevalent, sight-threatening ocular condition, especially in Asia. Without adequate interventions, the current epidemic of myopia is projected to affect 50% of the world population by 2050, becoming the leading cause of irreversible blindness. Although blurred vision, the predominant symptom of myopia, can be improved by contact lenses, glasses, or refractive surgery, corrected myopia, particularly high myopia, still carries the risk of secondary blinding complications such as glaucoma, myopic maculopathy, and retinal detachment, prompting the need for prevention. Epidemiological studies have reported an association between outdoor time and myopia prevention in children. The protective effect of time spent outdoors could be due to the unique characteristics (intensity, spectral distribution, temporal pattern, etc.) of sunlight that is lacking in artificial lighting. Concomitantly, studies in animal models have highlighted the efficacy of light and its components in delaying or even stopping the development of myopia and endeavoured to elucidate possible mechanisms involved in this process. In this narrative review, we (1) summarize the current knowledge concerning light modulation of ocular growth and refractive error development based on studies in human and animal models, (2) summarize potential neurobiological mechanisms involved in the effects of light on ocular growth and emmetropization and (3) highlight a potential pathway for the translational development of noninvasive light-therapy strategies for myopia prevention in children.info:eu-repo/semantics/publishedVersio

    Insights into the role of DNA methylation in diatoms by genome-wide profiling in Phaeodactylum tricornutum

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    DNA cytosine methylation is a widely conserved epigenetic mark in eukaryotes that appears to have critical roles in the regulation of genome structure and transcription. Genome-wide methylation maps have so far only been established from the supergroups Archaeplastida and Unikont. Here we report the first whole-genome methylome from a stramenopile, the marine model diatom Phaeodactylum tricornutum. Around 6% of the genome is intermittently methylated in a mosaic pattern. We find extensive methylation in transposable elements. We also detect methylation in over 320 genes. Extensive gene methylation correlates strongly with transcriptional silencing and differential expression under specific conditions. By contrast, we find that genes with partial methylation tend to be constitutively expressed. These patterns contrast with those found previously in other eukaryotes. By going beyond plants, animals and fungi, this stramenopile methylome adds significantly to our understanding of the evolution of DNA methylation in eukaryotes.Fil: Veluchamy, Alaguraj. Institut de Biologie de l'École Normale Supérieure; FranciaFil: Lin, Xin. Institut de Biologie de l'École Normale Supérieure; Francia. Xiamen University; ChinaFil: Maumus, Florian.Fil: Rivarola, Maximo Lisandro.Fil: Bhavsar, Jaysheel.Fil: Creasy, Todd.Fil: O'Brien, Kimberly.Fil: Sengamalay, Naomi A..Fil: Tallon, Luke J..Fil: Smith, Andrew D..Fil: Rayko, Edda.Fil: Ahmed, Ikhlak.Fil: Crom, Stéphane Le.Fil: Farrant, Gregory K..Fil: Sgro, Jean-Yves.Fil: Olson, Sue A..Fil: Bondurant, Sandra Splinter.Fil: Allen, Andrew.Fil: Rabinowicz, Pablo D..Fil: Sussman, Michael R..Fil: Bowler, Chris.Fil: Tirichine, Leïla

    On Unbounded Composition Operators in L2L^2-Spaces

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    Fundamental properties of unbounded composition operators in L2L^2-spaces are studied. Characterizations of normal and quasinormal composition operators are provided. Formally normal composition operators are shown to be normal. Composition operators generating Stieltjes moment sequences are completely characterized. The unbounded counterparts of the celebrated Lambert's characterizations of subnormality of bounded composition operators are shown to be false. Various illustrative examples are supplied
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