4,696 research outputs found

    Applications of Carbon Dots for the Photocatalytic and Electrocatalytic Reduction of CO2

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    The photocatalytic and electrocatalytic conversion of CO2 has the potential to provide valuable products, such as chemicals or fuels of interest, at low cost while maintaining a circular carbon cycle. In this context, carbon dots possess optical and electrochemical properties that make them suitable candidates to participate in the reaction, either as a single component or forming part of more elaborate catalytic systems. In this review, we describe several strategies where the carbon dots participate, both with amorphous and graphitic structures, in the photocatalysis or electrochemical catalysis of CO2 to provide different carbon-containing products of interest. The role of the carbon dots is analyzed as a function of their redox and light absorption characteristics and their complementarity with other known catalytic systems. Moreover, detailed information about synthetic procedures is also reviewed

    A comparative evaluation of interest point detectors and local descriptors for visual SLAM

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    Abstract In this paper we compare the behavior of different interest points detectors and descriptors under the conditions needed to be used as landmarks in vision-based simultaneous localization and mapping (SLAM). We evaluate the repeatability of the detectors, as well as the invariance and distinctiveness of the descriptors, under different perceptual conditions using sequences of images representing planar objects as well as 3D scenes. We believe that this information will be useful when selecting an appropriat

    A pedestrian path-planning model in accordance with obstacle's danger with reinforcement learning

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    Most microscopic pedestrian navigation models use the concept of "forces" applied to the pedestrian agents to replicate the navigation environment. While the approach could provide believable results in regular situations, it does not always resemble natural pedestrian navigation behaviour in many typical settings. In our research, we proposed a novel approach using reinforcement learning for simulation of pedestrian agent path planning and collision avoidance problem. The primary focus of this approach is using human perception of the environment and danger awareness of interferences. The implementation of our model has shown that the path planned by the agent shares many similarities with a human pedestrian in several aspects such as following common walking conventions and human behaviours

    Raman threshold for nth-order cascade Raman amplification

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    We study theoretically and experimentally Raman threshold for 1, 2, ... , n orders Stokes in a free running configuration. Using alternative way to solve the differential coupled equations that describe the stimulate Raman scattering, we find simple mathematical expressions that allow calculating the necessary pumping power to obtain Raman threshold for nth-order Stokes and the maximum output power available in each Stokes. The theoretical calculations coincide with the results obtained experimentally

    Placebo-controlled trial of nimodipine in the treatment of acute ischemic cerebral infarction

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    Nimodipine is a 1,4-dihydropyridine derivative that shows a preferential cerebrovascular activity in experimental animals. Clinical data suggest that nimodipine has a beneficial effect on the neurologic outcome of patients suffering an acute ischemic stroke. Our double-blind placebo-controlled multicenter trial was designed to assess the effects of oral nimodipine on the mortality rate and neurologic outcome of patients with an acute ischemic stroke. One hundred sixty-four patients were randomly allocated to receive either nimodipine tablets (30 mg q.i.d.) or identical placebo tablets for 28 days. Treatment was always started less than or equal to 48 hours after the acute event. The Mathew Scale, slightly modified by Gelmers et al, was used for neurologic assessment. Mortality rate and neurologic outcome after 28 days were used as evaluation criteria. We considered 123 patients to be valid for the analysis of efficacy. Mortality rates did not differ significantly between groups. Neurologic outcome after 28 days of therapy did not differ between groups. However, when only those patients most likely to benefit from any intervention (Mathew Scale sum score of less than or equal to 65 at baseline) were analyzed separately in post hoc-defined subgroups, the nimodipine-treated subgroups showed a significantly better neurologic outcome. This result suggests that some patients with acute ischemic stroke will benefit from treatment with nimodipine tablets

    The effect of age on the acquisition and selection of cancer driver mutations in sun-exposed normal skin

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    BACKGROUND: The accumulation of somatic mutations contributes to ageing and cancer. Sunlight is the principal aetiological factor associated with skin cancer development. However, genetic and phenotypic factors also contribute to skin cancer risk. This study aimed at exploring the role of photoaging, as well as other well-known epidemiological risk factors, in the accumulation of somatic mutations in cancer-free human epidermis. MATERIAL AND METHODS: We deeply sequenced 46 genes in normal skin biopsies from 127 healthy donors, from which phenotypic data (including age, pigmentation-related genotype and phenotype) and sun exposure habits were collected. We determined the somatic mutational burden, mutational signatures, clonal selection and frequency of driver mutations in all samples. RESULTS: Our results reveal an exponential accumulation of UV-related somatic mutations with age, matching skin cancer incidence. The increase of mutational burden is in turn modified by an individual's skin phototype. Somatic mutations preferentially accumulated in cutaneous squamous cell carcinoma (cSCC) cancer genes and clonally expanded with age, with distinct mutational processes underpinning different age groups. Our results suggest loss of fidelity in transcription-coupled repair later in life. CONCLUSION: Our findings reveal that aging is not only associated with an exponential increase in the number of somatic mutations accumulated in normal epidermis, but also with selection and expansion of cancer-associated mutations. Aged, sun-exposed normal skin is thus an extended mosaic of multiple clones with driver mutations, poised for the acquisition of transforming events

    Seminal plasma AnnexinA2 protein is a relevant biomarker for stallions which require removal of seminal plasma for sperm survival upon refrigeration

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    Some stallions yield ejaculates that do not tolerate conservation by refrigeration prior to artificial insemination (AI), showing improvement after removal of most of the seminal plasma (SP) by centrifugation. In this study, the SP-proteome of 10 different stallions was defined through high-performance liquid chromatography with tandem mass spectrometry and bioinformatic analysis in relation to the ability of the ejaculates to maintain semen quality when cooled and stored at 5°C. Stallions were classified into three groups, depending on this ability: those maintaining good quality after direct extension in a commercial extender (good), stallions requiring removal of seminal plasma (RSP) to maintain seminal quality (good-RSP), and stallions, unable to maintain good semen quality even after RSP (poor). Pathway enrichment analysis of the proteins identified in whole equine SP using human orthologs was performed using g: profiler showing enriched Reactome and the Kyoto Encyclopedia of Genes and Genomes pathways related to hexose metabolism, vesicle mediated transport, post translational modification of proteins and immune response. Specific proteins overrepresented in stallions tolerating conservation by refrigeration included a peroxiredoxin-6 like protein, and transcobalamin-2, a primary vitamin B12-binding, and transport protein. Also, the protein involved in protein glycosylation, ST3 beta-galactoside alpha-2,3-sialyltransferase 1 was present in good stallions. These proteins were nearly absent in poor stallions. Particularly, annexinA2 appeared as to be the most powerful discriminant variable for identification of stallions needing RSP prior to refrigeration, with a P = 0.002 and a q value = 0.005. Overall this is the first detailed study of the equine SP-proteome, showing the potential value of specific proteins as discriminant bio-markers for clinical classification of stallions for AI

    Nebulized ivermectin for COVID-19 and other respiratory diseases, a proof of concept, dose-ranging study in rats

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    Ivermectin is a widely used antiparasitic drug with known efcacy against several single-strain RNA viruses. Recent data shows signifcant reduction of SARS-CoV-2 replication in vitro by ivermectin concentrations not achievable with safe doses orally. Inhaled therapy has been used with success for other antiparasitics. An ethanol-based ivermectin formulation was administered once to 14 rats using a nebulizer capable of delivering particles with alveolar deposition. Rats were randomly assigned into three target dosing groups, lower dose (80–90 mg/kg), higher dose (110–140 mg/kg) or ethanol vehicle only. A toxicology profle including behavioral and weight monitoring, full blood count, biochemistry, necropsy and histological examination of the lungs was conducted. The pharmacokinetic profle of ivermectin in plasma and lungs was determined in all animals. There were no relevant changes in behavior or body weight. There was a delayed elevation in muscle enzymes compatible with rhabdomyolysis, that was also seen in the control group and has been attributed to the ethanol dose which was up to 11 g/kg in some animals. There were no histological anomalies in the lungs of any rat. Male animals received a higher ivermectin dose adjusted by adipose weight and reached higher plasma concentrations than females in the same dosing group (mean Cmax 86.2 ng/ml vs. 26.2 ng/ ml in the lower dose group and 152 ng/ml vs. 51.8 ng/ml in the higher dose group). All subjects had detectable ivermectin concentrations in the lungs at seven days post intervention, up to 524.3 ng/g for high-dose male and 27.3 ng/g for low-dose females. nebulized ivermectin can reach pharmacodynamic concentrations in the lung tissue of rats, additional experiments are required to assess the safety of this formulation in larger animals

    Recovering Old Grapevine Varieties

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    [EN] In this work we report new findings related to the recovery of old vines in The Comunitat Valenciana (Spain), where great diversity of grapevines varieties was present prior the phylloxera arrival. New accessions of old varieties previously recovered by our group and in risk of disappearance were located. Accessions with new SSR profiles were also found and, in some cases, could be ascribed to old grapevine ampelonyms; new synonymies were also detected. Chlorotypes were determined in the recovered germplasm. Several actions for the preservation of the recovered accessions have been initiated.This work was supported by the projects 'Recuperacion de variedades de vid', AGCOOP_D/2018/007' (co-funded by FEADER, MAPA and Conselleria d'Agricultura, Desenvolupament Rural, Emergencia Climatica i Transicio Ecologica (Generatitat Valenciana) and MINECO CGL2015-708432-R (co-funded by FEDER). We thank the IMIDRA and The Domain the Vassal Collection that provided two accessions each used as controls in our workGarcía, J.; Peiró Barber, RM.; Martinez-Gil, F.; Soler, JX.; Jimenez, C.; Yuste Del Carmen, A.; Xirivella, C.... (2020). Recovering Old Grapevine Varieties. VITIS. 59(3):101-103. https://doi.org/10.5073/vitis.2020.59.101-103S10110359
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