799 research outputs found
Isotope analysis in central heavy ion collisions at intermediate energies
Symmetry energy is a key quantity in the study of the equation of state of
asymmetric nuclear matter. Heavy ion collisions at low and intermediate
energies, performed at Laboratori Nazionali di Legnaro and Laboratori Nazionali
del Sud, can be used to extract information on the symmetry energy coefficient
Csym, which is currently poorly known but relevant both for astrophysics and
for structure of exotic nuclei.Comment: 2 pages, 1 figure. Proceedings of 7th International Conference on
Radioactive Nuclear Beams (RNB7), to be published in The European Physical
Journal
Historical silk: a novel method to evaluate degumming with non-invasive infrared spectroscopy and spectral deconvolution
: To correctly manage a collection of historical silks, it is important to detect if the yarn has been originally subjected to degumming. This process is generally applied to eliminate sericin; the obtained fiber is named soft silk, in contrast with hard silk which is unprocessed. The distinction between hard and soft silk gives both historical information and useful indications for informed conservation. With this aim, 32 samples of silk textiles from traditional Japanese samurai armors (15th-20th century) were characterized in a non-invasive way. ATR-FTIR spectroscopy has been previously used to detect hard silk, but data interpretation is challenging. To overcome this difficulty, an innovative analytical protocol based on external reflection FTIR (ER-FTIR) spectroscopy was employed, coupled with spectral deconvolution and multivariate data analysis. The ER-FTIR technique is rapid, portable, and widely employed in the cultural heritage field, but rarely applied to the study of textiles. The ER-FTIR band assignment for silk was discussed for the first time. Then, the evaluation of the OH stretching signals allowed for a reliable distinction between hard and soft silk. Such an innovative point of view, which exploits a "weakness" of FTIR spectroscopy-the strong absorption from water molecules-to indirectly obtain the results, can have industrial applications too
An Interplay between a Face-Centred Composite Experimental Design and Solid-Phase Microextraction for Wine Aroma GC/MS Analysis
For oenological products, most of the intrinsic and extrinsic drivers of perceived quality are associated with specific aromatic profiles. Aromatic diversity has been recognized as a central element in perceived quality as it is able to transmit the complex interactions between grape variety, geographical characteristics, and viticultural and winemaking practices, including the fermentative process. A comprehensive characterization of flavour compounds by headspace solid-phase microextraction (HS-SPME) and gas chromatography coupled to mass spectrometric analysis is often needed in order to ascertain the quality of wine. HS-SPME requires a proper optimization that can be achieved through an adequate experimental design. Here, a HS-SPME/GC-MS based method was developed to investigate the volatile compounds of wine samples obtained by laboratory-scale fermentations. This was performed by inoculating a commercial Saccharomyces cerevisiae strain, which is used both as single starter and as mixed starter, with an indigenous Hanseniaspora osmophila strain. The experimental conditions of HS-SPME (extraction temperature and time) were optimized by applying a face-centred composite experimental design. Up to 95% of the total variance was explained by the proposed model. The optimized method allowed us to confirm the usefulness of combining the inoculation of grapes with selected yeast strains in co-culture situations in order to improve the wine bouquet
Effect of human skin-derived stem cells on vessel architecture, tumor growth, and tumor invasion in brain tumor animal models
Glioblastomas represent an important cause of cancer-related mortality with poor survival. Despite many advances, the mean survival time has not significantly improved in the last decades. New experimental approaches have shown tumor regression after the grafting of neural stem cells and human mesenchymal stem cells into experimental intracranial gliomas of adult rodents. However, the cell source seems to be an important limitation for autologous transplantation in glioblastoma. In the present study, we evaluated the tumor targeting and antitumor activity of human skin-derived stem cells (hSDSCs) in human brain tumor models. The hSDSCs exhibit tumor targeting characteristics in vivo when injected into the controlateral hemisphere or into the tail vein of mice. When implanted directly into glioblastomas, hSDSCs distributed themselves extensively throughout the tumor mass, reduced tumor vessel density, and decreased angiogenic sprouts. In addition, transplanted hSDSCs differentiate into pericyte cell and release high amounts of human transforming growth factor-beta1 with low expression of vascular endothelial growth factor, which may contribute to the decreased tumor cell invasion and number of tumor vessels. In long-term experiments, the hSDSCs were also able to significantly inhibit tumor growth and to prolong animal survival. Similar behavior was seen when hSDSCs were implanted into two different tumor models, the chicken embryo experimental glioma model and the transgenic Tyrp1-Tag mice. Taken together, these data validate the use of hSDSCs for targeting human brain tumors. They may represent therapeutically effective cells for the treatment of intracranial tumors after autologous transplantation
Active role of the mucilage in the toxicity mechanism of the harmful benthic dinoflagellate Ostreopsis cf. ovata.
Ostreopsis cf. ovata is a harmful benthic dinoflagellate, widespread along most of the Mediterranean
coasts. It produces a wide range of palytoxin-like compounds and variable amounts of mucus that may
totally cover substrates, especially during the stationary phase of blooms. Studies on different aspects of
the biology and ecology of Ostreopsis spp. are increasing, yet knowledge on toxicity mechanism is still
limited. In particular, the potential active role of the mucilaginous matrix has not yet been shown,
although when mass mortalities have occurred, organisms have been reported to be covered by the
typical brownish mucilage. In order to better elucidate toxicity dependence on direct/indirect contact,
the role of the mucilaginous matrix and the potential differences in toxicity along the growth curve of O.
cf. ovata, we carried out a toxic bioassay during exponential, stationary and late stationary phases.
Simultaneously, a molecular assay was performed to quantify intact cells or to exclude cells presence. A
liquid chromatography – high resolution mass spectrometry (LC-HRMS) analysis was also carried out to
evaluate toxin profile and content in the different treatments. Our results report higher mortality of
model organism, especially during the late stationary phase, when direct contact between a model
organism and intact microalgal cells occurs (LC50-48h <4 cells/ml on Artemia salina). Also growth
medium devoid of microalgal cells but containing O. cf. ovata mucilage caused significant toxic effects.
This finding is also supported by chemical analysis which shows the highest toxin content in pellet
extract (95%) and around 5% of toxins in the growth medium holding mucous, while the treatment
devoid of both cells and mucilage did not contain any detectable toxins. Additionally, the connection
between mucilaginous matrix and thecal plates, pores and trychocysts was explored by way of atomic
force microscopy (AFM) to investigate the cell surface at a sub-nanometer resolution, providing a
pioneering description of cellular features
Metal - Insulator transition driven by vacancy ordering in GeSbTe phase change materials
Phase Change Materials (PCMs) are unique compounds employed in non-volatile random access memory thanks to the rapid and reversible transformation between the amorphous and crystalline state that display large differences in electrical and optical properties. In addition to the amorphous-to-crystalline transition, experimental results on polycrystalline GeSbTe alloys (GST) films evidenced a Metal-Insulator Transition (MIT) attributed to disorder in the crystalline phase. Here we report on a fundamental advance in the fabrication of GST with out-of-plane stacking of ordered vacancy layers by means of three distinct methods: Molecular Beam Epitaxy, thermal annealing and application of femtosecond laser pulses. We assess the degree of vacancy ordering and explicitly correlate it with the MIT. We further tune the ordering in a controlled fashion attaining a large range of resistivity. Employing ordered GST might allow the realization of cells with larger programming windows
The Effects of an Acceptance and Commitment-Informed Interdisciplinary Rehabilitation Program for Chronic Airway Diseases on Health Status and Psychological Symptoms
Background: Chronic airway diseases are prevalent and costly conditions. Interdisciplinary rehabilitation programs that include Acceptance and Commitment-based (ACT) components could be important to tackle the vicious circle linking progression of the disease, inactivity, and psychopathological symptoms. Methods: A retrospective evaluation of routinely collected data of an interdisciplinary rehabilitation program was performed. The program included group sessions including patient education, breathing exercise, occupational therapy and an ACT-based psychological treatment, and individual sessions of physical therapy. Demographic data, clinical characteristics of the patients and the values of outcome variables (health status, quality of life, anxiety, and depression) before treatment, at discharge, at 3 months, and at 6 months were extracted from medical records. Multiple imputation was employed to address missing data. Linear mixed models were employed to assess changes over time. Multivariable logistic regression was performed to assess predictors of a minimum clinically important change of health status from baseline to the 6-months follow-up. Results: Data from 31 patients with chronic obstructive pulmonary disease (COPD) and 12 patients with bronchiectasis were extracted. Health status improved from baseline to discharge to the 3 months follow-up, but not to the 6 months follow-up. Anxiety and depression improved across all the time points. Quality of life did not improve over time. Having a worse health status at baseline and fewer depressive symptoms were significantly associated with achieving a minimum clinically important change of health status at 6 months. The effects of the interdisciplinary program were not different for patients with COPD or with bronchiectasis. Discussion: Interdisciplinary programs including ACT-based components are promising treatments for the rehabilitation of patients with chronic airway diseases
Metal - Insulator transition driven by vacancy ordering in GeSbTe phase change materials
Phase Change Materials (PCMs) are unique compounds employed in non-volatile random access memory thanks to the rapid and reversible transformation between the amorphous and crystalline state that display large differences in electrical and optical properties. In addition to the amorphousto-crystalline transition, experimental results on polycrystalline GeSbTe alloys (GST) films evidenced a Metal-Insulator Transition (MIT) attributed to disorder in the crystalline phase. Here we report on a fundamental advance in the fabrication of GST with out-of-plane stacking of ordered vacancy layers by means of three distinct methods: Molecular Beam Epitaxy, thermal annealing and application of femtosecond laser pulses. We assess the degree of vacancy ordering and explicitly correlate it with the MIT. We further tune the ordering in a controlled fashion attaining a large range of resistivity. Employing ordered GST might allow the realization of cells with larger programming windows
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