Absorption, luminescence and scattering of single nano-objects

We study the technique of photothermal microscopy by which we can detect single nano-objects by their absorption at room temperature. We optimize the sensitivity of this technique and demonstrate the first optical detection of a single molecule by its absorption at room temperature. Moreover, we combine photothermal, luminescence and scattering of individual nano-objects (organic dye nanoparticles and gold nanoparticles) at single-particle level to gain insight into their radiative and nonradiative properties. Single organic nanoparticles exhibit a complex excitation power-dependent luminescence quantum yield due to singlet-singlet or singlet-triplet annihilation, and their luminescence quantum yield can be as high as 10^(__2). In contrast to organic dye nanoparticles, gold nanoparticles yield very stable optical signals. Gold nanoparticles are also easily detectable by their photoluminescence. We find that the luminescence quantum yield of single gold nanoparticles is nearly independent of their volumes and can be as high as ~10^(-5) for nanorods with a plasmon resonance of ~650 nm. We further investigate the sensitivity of a single gold nanorod to an approaching dielectric surface. We show that the nanorod exhibits significant red-shift in its plasmon resonance wavelength for distances less than 400 nm pointing the way towards the possible application of nanorods as distance sensors.Seventh Framework Programme (FP7)Biological and Soft Matter Physic

Efecto de la temperatura de molturación sobre la composición y calidad del aceite de oliva virgen

The objective of the current study was to assess the influence of a modified crushing process and kneading operation on the quality parameters, volatile compounds, and the fatty acid and sterol profiles of virgin olive oil from the Edremit yaglik variety. In the study, olive oil samples were produced in two different processes. The first one was produced without malaxation and the second one was produced with the malaxing process. During crushing, the effect of different temperatures was tested. The results demonstrate that different crushing temperatures generally did not affect the amount of free fatty acids, or peroxide value. Total phenol contents were positively affected by the additional malaxation process. Fatty acids and sterol composition were not significantly altered at different crushing temperatures or during the subsequent malaxation application. PCA enabled a clear classification of the oils obtained from different processing techniques.El objetivo del presente estudio fue evaluar la influencia de un proceso de molturación modificado y de la etapa de batido sobre los parámetros de calidad, los componentes volátiles, los ácidos grasos y el perfil de esteroles de aceites de oliva virgen de la variedad Edremit yaglik. En este estudio, las muestras de aceite de oliva se obtuvieron mediante dos procesos diferentes con y sin malaxación. Durante la trituración, se probó el efecto de diferentes temperaturas. Los resultados demostraron que las diferentes temperaturas de trituración, en general, no mostraron tener efecto sobre la cantidad de ácidos grasos libres o el índice de peróxido. El contenido total de fenoles se vio afectado positivamente por el empleo de malaxación. La composición de ácidos grasos y de esteroles no se vieron afectados significativamente por el aumento de la temperatura en la trituración ni durante el proceso de malaxación. PCA permitió una clasificación clara de los aceites obtenidos mediante las diferentes técnicas de procesamiento

The impact of pretreatment with simvastatin on kidney tissue of rats with acute sepsis

It has been reported that changes in cytokine levels affect mitochondrial functions, levels of hypoxia-inducible factor α (HIF-1α), and tissue damage during sepsis. We aimed to investigate the effects of simvastatin pretreatment on mitochondrial enzyme activities, and on levels of ghrelin, HIF-1α, and thiobarbituric acid reactive substances (TBARS) in kidney tissue during sepsis. Rats were separated into four groups, namely, control, lipopolysaccharides (LPS) (20 mg/kg), simvastatin (20 mg/kg), and simvastatin + LPS. We measured the levels of mitochondrial enzyme activities and TBARS in the kidney using spectrophotometry. The histological structure of the kidney sections was examined after staining with hematoxylin and eosin. Tumor necrosis factor α (TNF-α), IL-10, HIF-1α, and ghrelin immunoreactivity were examined using proper antibodies. In tissue, TNF-α (p  0.05). Ghrelin immunoreactivity was lower in the LPS group (p  0.05). We observed that pretreatment of simvastatin caused favorable changes on ghrelin and TBARS levels in rats with sepsis

Phase and TV Based Convex Sets for Blind Deconvolution of Microscopic Images

In this paper, two closed and convex sets for blind deconvolution problem are proposed. Most blurring functions in microscopy are symmetric with respect to the origin. Therefore, they do not modify the phase of the Fourier transform (FT) of the original image. As a result blurred image and the original image have the same FT phase. Therefore, the set of images with a prescribed FT phase can be used as a constraint set in blind deconvolution problems. Another convex set that can be used during the image reconstruction process is the Epigraph Set of Total Variation (ESTV) function. This set does not need a prescribed upper bound on the Total Variation (TV) of the image. The upper bound is automatically adjusted according to the current image of the restoration process. Both the TV of the image and the blurring filter are regularized using the ESTV set. Both the phase information set and the ESTV are closed and convex sets. Therefore they can be used as a part of any blind deconvolution algorithm. Simulation examples are presented. © 2015 IEEE

Academic student satisfaction and perceived performance in the e-learning environment during the COVID-19 pandemic: Evidence across ten countries

The outbreak of the COVID-19 pandemic has dramatically shaped higher education and seen the distinct rise of e-learning as a compulsory element of the modern educational landscape. Accordingly, this study highlights the factors which have influenced how students perceive their academic performance during this emergency changeover to e-learning. The empirical analysis is performed on a sample of 10,092 higher education students from 10 countries across 4 continents during the pandemic’s first wave through an online survey. A structural equation model revealed the quality of e-learning was mainly derived from service quality, the teacher’s active role in the process of online education, and the overall system quality, while the students’ digital competencies and online interactions with their colleagues and teachers were considered to be slightly less important factors. The impact of e-learning quality on the students’ performance was strongly mediated by their satisfaction with e-learning. In general, the model gave quite consistent results across countries, gender, study fields, and levels of study. The findings provide a basis for policy recommendations to support decision-makers incorporate e-learning issues in the current and any new similar circumstances.info:eu-repo/semantics/publishedVersio

Archaeogenetic analysis of Neolithic sheep from Anatolia suggests a complex demographic history since domestication

Sheep were among the first domesticated animals, but their demographic history is little understood. Here we analyzed nuclear polymorphism and mitochondrial data (mtDNA) from ancient central and west Anatolian sheep dating from Epipaleolithic to late Neolithic, comparatively with modern-day breeds and central Asian Neolithic/Bronze Age sheep (OBI). Analyzing ancient nuclear data, we found that Anatolian Neolithic sheep (ANS) are genetically closest to present-day European breeds relative to Asian breeds, a conclusion supported by mtDNA haplogroup frequencies. In contrast, OBI showed higher genetic affinity to present-day Asian breeds. These results suggest that the east-west genetic structure observed in present-day breeds had already emerged by 6000 BCE, hinting at multiple sheep domestication episodes or early wild introgression in southwest Asia. Furthermore, we found that ANS are genetically distinct from all modern breeds. Our results suggest that European and Anatolian domestic sheep gene pools have been strongly remolded since the Neolithic

Higher education students’ achievement emotions and their antecedents in e-learning amid COVID-19 pandemic: A multi-country survey

The outbreak of the COVID-19 pandemic has had a wide range of negative consequences for higher education students. We explored the generalizability of the control-value theory of achievement emotions for e-learning, focusing on their antecedents. We involved 17019 higher education students from 13 countries, who completed an online survey during the first wave of the pandemic. A structural equation model revealed that proximal antecedents (e-learning self-efficacy, computer self-efficacy) mediated the relation between environmental antecedents (cognitive and motivational quality of the task) and positive and negative achievement emotions, with some exceptions. The model was invariant across country, area of study, and gender. The rates of achievement emotions varied according to these same factors. Beyond their theoretical relevance, these findings could be the basis for policy recommendations to support stakeholders in coping with the challenges of e-learning and the current and future sequelae of the pandemic.info:eu-repo/semantics/publishedVersio

Unexplored olive cultivars from the Valencian Community (Spain): some chemical characteristics as a valorization strategy

[EN] The olive processing industry has till date been dominated by a small group of cultivars, leading to the possibility of some olive cultivars becoming extinct in the near future. In this study, we determined the composition of some chemical components in the olive oils from 31 minor olive cultivars of the Valencian Community. Our main aim was to identify suitable cultivars, which could produce differentiated olive oils, thus aiming towards their valorization. The average oil content of minor olive cultivars was found to be good, with some of them reporting approximately 60% (dry basis). On average, the total phenolic content was 229mg kg(-1), with cv. Mas Blanc reporting the highest content (570mg kg(-1)). Among the various tocopherols found in olives, -tocopherol was the main constituent, with a maximum concentration of 290.6mg kg(-1). Linoleic acid was the main polyunsaturated fatty acid and varied between 3.4% (cv. Del Pomet) and 16.9% (cv. Blanqueta Enguera). Special attention needs to be paid to the composition of sterols, since some olive oils exceeded the limits established for some sterols by the current European legislation. Some of the cultivars studied were highly productive, and originated differentiated olive oils with a rich composition of antioxidants and essential fatty acids. In some cases, these beneficial compounds were higher than those of commercial oils obtained from the most common cultivars worldwide. These results could contribute to the commercial exploitation of some of the studied cultivars.Salazar-García, DC.; Malheiro, R.; Pereira, JA.; López- Cortés, I. (2019). Unexplored olive cultivars from the Valencian Community (Spain): some chemical characteristics as a valorization strategy. 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