164 research outputs found

    A note on the sunspot and prominence records made by Angelo Secchi during the period 1871–1875

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    Angelo Secchi (1818–1878) was an Italian Jesuit who made relevant scientific contributions in geophysics, meteorology, and astrophysics. He was a well-known pioneer in solar physics due to his theories and observations. Secchi published Le Soleil (The Sun) a summary of knowledge about our star in that time. Moreover, he published in this book his sunspot and prominence observations made during the period 1871–1875. In this work, we present a machine-readable version of these observations and a preliminary analysis of them

    Instability of cosmological event horizons of non-static global cosmic strings

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    The stability of the cosmological event horizons found recently by Gregory [Phys. Rev. D54, 4955 (1996)] for a class of non-static global cosmic strings is studied. It is shown that they are not stable to both test particles and physical perturbations. In particular, the back reaction of the perturbations of null dust fluids will turn them into spacetime singularities. The resulted singularities are strong in the sense that the distortion of test particles diverges logarithmically when these singular hypersurfaces are approaching.Comment: Latex, no figure

    Exciting and confining light in Cr doped gallium oxide

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    On one hand, interest on the tunability of the optical microcavities has increased in the last few years due to the need for selective nano-and microscale light sources to be used as photonic building blocks in several applications. On the other, transparent conductive oxide (TCO) beta-Ga_2O_3 is attracting attention in the optoelectronics area due to its ultra wide band gap and high breakdown field. However, at the micro- and nanoscale there are still some challenges to face up, namely the control and tuning of the optical and electrical properties of this oxide. In this work, Cr doped Ga_2O_3 elongated microwires are grown using the vapor-solid (VS) mechanism. Focused Ion Beam (FIB) etching forms Distributed Bragg Reflector (DBR)-based resonant microcavities. Room temperature microphotoluminescence (mu-PL) spectra show strong modulations in the red-NIR range on five cavities with different lengths. Selectivity of the peak wavelengths is obtained, proving the tunability of this kind of optical systems. The confined modes are analyzed experimentally, analytically and via finite difference time domain (FDTD) simulations. Experimental reflectivities up to 78% are observed

    Brain aging and Parkinson's disease: new therapeutic approaches using drugs delivery systems

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    ABSTRACT The etiology and pathogenesis of Parkinson’s disease (PD) is unknown, aging being the strongest risk factor for brain degeneration. Understanding PD pathogenesis and how aging increases the risk of disease would aid the development of therapies able to slow or prevent the progression of this neurodegenerative disorder. In this review we provide an overview of the most promising therapeutic targets and strategies to delay the loss of dopaminergic neurons observed both in PD and aging. Among them, handling alphasynuclein toxicity, enhancing proteasome and lysosome clearance, ameliorating mitochondrial disruptions and modifying the glial environment are so far the most promising candidates. These new and conventional drugs may present problems related to their labile nature and to the difficulties in reaching the brain. Thus, we highlight the latest types of drug delivery system (DDS)-based strategies for PD treatment, including DDS for local and systemic drug delivery. Finally, the ongoing challenges for the discovery of new targets and the opportunities for DDS-based therapies to improve and efficacious PD therapy will be discussed

    Click-chemistry mediated synthesis of OTBN-1,2,3-Triazole derivatives exhibiting STK33 inhibition with diverse anti-cancer activities

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    There is a continuous and pressing need to establish new brain-penetrant bioactive compounds with anti-cancer properties. To this end, a new series of 4′-((4-substituted-4,5-dihydro-1H-1,2,3-triazol-1-yl)methyl)-[1,1′-biphenyl]-2-carbonitrile (OTBN-1,2,3-triazole) derivatives were synthesized by click chemistry. The series of bioactive compounds were designed and synthesized from diverse alkynes and N3-OTBN, using copper (II) acetate monohydrate in aqueous dimethylformamide at room temperature. Besides being highly cost-effective and significantly reducing synthesis, the reaction yielded 91–98 % of the target products without the need of any additional steps or chromatographic techniques. Two analogues exhibit promising anti-cancer biological activities. Analogue 4l shows highly specific cytostatic activity against lung cancer cells, while analogue 4k exhibits pan-cancer anti-growth activity. A kinase screen suggests compound 4k has single-digit micromolar activity against kinase STK33. High STK33 RNA expression correlates strongly with poorer patient outcomes in both adult and pediatric glioma. Compound 4k potently inhibits cell proliferation, invasion, and 3D neurosphere formation in primary patient-derived glioma cell lines. The observed anti-cancer activity is enhanced in combination with specific clinically relevant small molecule inhibitors. Herein we establish a novel biochemical kinase inhibitory function for click-chemistry-derived OTBN-1,2,3-triazole analogues and further report their anti-cancer activity in vitro for the first time

    Click-chemistry mediated synthesis of OTBN-1,2,3-Triazole derivatives exhibiting STK33 inhibition with diverse anti-cancer activities

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    There is a continuous and pressing need to establish new brain-penetrant bioactive compounds with anti-cancer properties. To this end, a new series of 4′-((4-substituted-4,5-dihydro-1H-1,2,3-triazol-1-yl)methyl)-[1,1′-biphenyl]-2-carbonitrile (OTBN-1,2,3-triazole) derivatives were synthesized by click chemistry. The series of bioactive compounds were designed and synthesized from diverse alkynes and N3-OTBN, using copper (II) acetate monohydrate in aqueous dimethylformamide at room temperature. Besides being highly cost-effective and significantly reducing synthesis, the reaction yielded 91–98 % of the target products without the need of any additional steps or chromatographic techniques. Two analogues exhibit promising anti-cancer biological activities. Analogue 4l shows highly specific cytostatic activity against lung cancer cells, while analogue 4k exhibits pan-cancer anti-growth activity. A kinase screen suggests compound 4k has single-digit micromolar activity against kinase STK33. High STK33 RNA expression correlates strongly with poorer patient outcomes in both adult and pediatric glioma. Compound 4k potently inhibits cell proliferation, invasion, and 3D neurosphere formation in primary patient-derived glioma cell lines. The observed anti-cancer activity is enhanced in combination with specific clinically relevant small molecule inhibitors. Herein we establish a novel biochemical kinase inhibitory function for click-chemistry-derived OTBN-1,2,3-triazole analogues and further report their anti-cancer activity in vitro for the first time

    A multiple stakeholder multicriteria decision analysis in diabetic macular edema management: the MULTIDEX‑EMD study

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    Background The clinical and economic management of retinal diseases has become more complex following the introduction of new intravitreal treatments. Multicriteria decision analysis (MCDA) ofers the potential to overcome the challenges associated with traditional decision-making tools. Objectives A MCDA to determine the most relevant criteria to decision-making in the management of diabetic macular edema (DME) based on the perspectives of multiple stakeholders in Spain was developed. This MCDA was termed the MULTIDEX-EMD study. Methods Nineteen stakeholders (7 physicians, 4 pharmacists, 5 health authorities and health management experts, 1 psychologist, and 2 patient representatives) participated in this three-phase project. In phase A, an advisory board defned all of the criteria that could infuence DME treatment decision-making. These criteria were then screened using a discrete choice experiment (DCE) (phase B). Next, a multinomial logit model was ftted by applying the backward elimination algorithm (relevant criteria: p value<0.05). Finally, the results were discussed in a deliberative process (phase C). Results Thirty-one criteria were initially defned (phase A) and grouped into 5 categories: efcacy/efectiveness, safety, organizational and economic impact, patient-reported outcomes, and other therapeutic features. The DCE results (phase B) showed that 10 criteria were relevant to the decision-making process for a 50- to 65-year-old DME patient: mean change in best corrected visual acuity (p value<0.001), percentage of patients with an improvement of ≥15 letters (p value<0.001), efect duration per administration (p value=0.008), retinal detachment (p value<0.001), endophthalmitis (p value=0.012), myocardial infarction (p value<0.001), intravitreal hemorrhage (p value=0.021), annual treatment cost per patient (p value=0.001), health-related quality of life (HRQoL) (p value=0.004), and disability level (p value=0.021). Conclusions From a multi-stakeholder perspective, the selection of an appropriate treatment for DME patients should guarantee patient safety and maximize the visual acuity improvement and treatment efect duration. It should also contribute to system sustainability by being afordable, it should have a positive impact on HRQoL, and it should prevent disability

    Impaired PLP-dependent metabolism in brain samples from Huntington disease patients and transgenic R6/1 mice

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    Oxidative stress has been described as important to Huntington disease (HD) progression. In a previous HD study, we identified several carbonylated proteins, including pyridoxal kinase and antiquitin, both of which are involved in the metabolism of pyridoxal 5´-phosphate (PLP), the active form of vitamin B6. In the present study, pyridoxal kinase levels were quantified and showed to be decreased both in HD patients and a R6/1 mouse model, compared to control samples. A metabolomic analysis was used to analyze metabolites in brain samples of HD patients and R6/1 mice, compared to control samples using mass spectrometry. This technique allowed detection of increased concentrations of pyridoxal, the substrate of pyridoxal kinase. In addition, PLP, the product of the reaction, was decreased in striatum from R6/1 mice. Furthermore, glutamate and cystathionine, both substrates of PLP-dependent enzymes were increased in HD. This reinforces the hypothesis that PLP synthesis is impaired, and could explain some alterations observed in the disease. Together, these results identify PLP as a potential therapeutic agent

    A green bio-organic catalyst (taurine) promoted one-pot synthesis of (R/S)-2-thioxo-3,4-dihydropyrimidine(TDHPM)-5-carboxanilides: chiral investigations using circular dichroism and validation by computational approaches

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    Owing to the massive importance of dihydropyrimidine (DHPMs) scaffolds in the pharmaceutical industry and other areas, we developed an effective and sustainable one-pot reaction protocol for the synthesis of (R/S)-2-thioxo-DHPM-5-carboxanilides via the Biginelli-type cyclo-condensation reaction of aryl aldehydes, thiourea and various acetoacetanilide derivatives in ethanol at 100 °C. In this protocol, taurine was used as a green and reusable bio-organic catalyst. Twenty-three novel derivatives of (R/S)-TDHPM-5-carboxanilides and their structures were confirmed by various spectroscopy techniques. The aforementioned compounds were synthesized via the formation of one asymmetric centre, one new C–C bond, and two new C–N bonds in the final product. All the newly synthesized compounds were obtained in their racemic form with up to 99% yield. In addition, the separation of the racemic mixture of all the newly synthesized compounds was carried out by chiral HPLC (Prep LC), which provided up to 99.99% purity. The absolute configuration of all the enantiomerically pure isomers was determined using a circular dichroism study and validated by a computational approach. With up to 99% yield of 4d, this one-pot synthetic approach can also be useful for large-scale industrial production. One of the separated isomers (4R)-(+)-4S developed as a single crystal, and it was found that this crystal structure was orthorhombic

    A New Mouse Model for Marfan Syndrome Presents Phenotypic Variability Associated with the Genetic Background and Overall Levels of Fbn1 Expression

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    Marfan syndrome is an autosomal dominant disease of connective tissue caused by mutations in the fibrillin-1 encoding gene FBN1. Patients present cardiovascular, ocular and skeletal manifestations, and although being fully penetrant, MFS is characterized by a wide clinical variability both within and between families. Here we describe a new mouse model of MFS that recapitulates the clinical heterogeneity of the syndrome in humans. Heterozygotes for the mutant Fbn1 allele mgΔloxPneo, carrying the same internal deletion of exons 19–24 as the mgΔ mouse model, present defective microfibrillar deposition, emphysema, deterioration of aortic wall and kyphosis. However, the onset of a clinical phenotypes is earlier in the 129/Sv than in C57BL/6 background, indicating the existence of genetic modifiers of MFS between these two mouse strains. In addition, we characterized a wide clinical variability within the 129/Sv congenic heterozygotes, suggesting involvement of epigenetic factors in disease severity. Finally, we show a strong negative correlation between overall levels of Fbn1 expression and the severity of the phenotypes, corroborating the suggested protective role of normal fibrillin-1 in MFS pathogenesis, and supporting the development of therapies based on increasing Fbn1 expression
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