4,112 research outputs found

    Microscopic mechanism of protein cryopreservation in an aqueous solution with trehalose

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    In order to investigate the cryoprotective mechanism of trehalose on proteins, we use molecular dynamics computer simulations to study the microscopic dynamics of water upon cooling in an aqueous solution of lysozyme and trehalose. We find that the presence of trehalose causes global retardation of the dynamics of water. Comparing aqueous solutions of lysozyme with/without trehalose, we observe that the dynamics of water in the hydration layers close to the protein is dramatically slower when trehalose is present in the system. We also analyze the structure of water and trehalose around the lysozyme and find that the trehalose molecules form a cage surrounding the protein that contains very slow water molecules. We conclude that the transient cage of trehalose molecules that entraps and slows the water molecules prevents the crystallisation of protein hydration water upon cooling.DC, EGS, and HES thank the NSF chemistry Division for support (Grants CHE-1213217, CHE-0911389, and CHE-0908218). PG gratefully acknowledges the computational support reveived by the INFN RM3-GRID at Roma Tre University. (CHE-1213217 - NSF chemistry Division; CHE-0911389 - NSF chemistry Division; CHE-0908218 - NSF chemistry Division)Published versio

    The demand for bank loans in Italy at national and macro-regional level (1984-96)

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    Bank lending expanded rapidly in Italy in the second half of the 1980s and early 1990s. By contrast, in the four years 1993-96 it rose moderately, and in real terms it diminished. The paper addresses some questions in the light of these trends: Was there a structural change in firms’ demand for credit after 1993? Are there systematic differences in the parameters of the demand for loans in the different parts of Italy? If such differences do exist, how have they influenced recent developments in credit? The evidence presented delineates a rather clear picture. At national level the demand for loans was stable during the observation period. The deceleration in lending is ascribable in small part (about 3 percentage points on an annualized basis ) to the increase in the opportunity cost of loans; it was due largely (about 10 percentage points on an annualized basis) to the sizable decrease in business investment in relation to firms’ gross margins. The demand for loans displays differing characteristics in the different parts of Italy. In particular, its elasticity to interest rates was lower and its elasticity to investment higher in the North-East than in the other parts of the country. It is possible that changes occurred in the demand function in the North-West and the Centre.bank loans, Italy, regional

    Optimization of an in vitro transcription/translation system based on Sulfolobus solfataricus cell lysate.

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    A system is described which permits the efficient synthesis of proteins in vitro at high temperature. It is based on the use of an unfractionated cell lysate (S30) from Sulfolobus solfataricus previously well characterized in our laboratory for translation of pre-transcribed mRNAs, and now adapted to perform coupled transcription and translation. The essential element in this expression system is a strong promoter derived from the S. solfataricus 16S/23S rRNA-encoding gene, from which specific mRNAs may be transcribed with high efficiency. The synthesis of two different proteins is reported, including the S. solfataricus DNA-alkylguanine-DNA-alkyl-transferase protein (SsOGT), which is shown to be successfully labeled with appropriate fluorescent substrates and visualized in cell extracts. The simplicity of the experimental procedure and specific activity of the proteins offer a number of possibilities for the study of structure-function relationships of proteins

    Sunday consumer behavior: A case study in retail marketing

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    The Sunday opening of shops is a very debated topic on both international and national levels. On a European level, the regulation of Sunday work is varied, with most Member States that, like Italy, do not impose restrictions on openings and working hours. The present work aims to analyze the European reference framework of Sunday openings, focusing on the Italian situation, which is currently experiencing proposals for change. Moreover, from the statistical analysis of the purchase data made in the main Italian stores of a multinational company, the "profile of the Sunday consumer" is highlighted, analyzing the characteristics and peculiarities that orient Sunday shopping. The Two Step cluster analysis provides different profiles, among which emerges the consumer profile of Sunday, which assumes peculiar characteristics and different from those of consumers of the other days of the week

    Effect of hydrophobic solutes on the liquid-liquid critical point

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    Jagla ramp particles, interacting through a ramp potential with two characteristic length scales, are known to show in their bulk phase thermodynamic and dynamic anomalies, similar to what is found in water. Jagla particles also exhibit a line of phase transitions separating a low density liquid phase and a high density liquid phase, terminating in a liquid-liquid critical point in a region of the phase diagram that can be studied by simulations. Employing molecular dynamics computer simulations, we study the thermodynamics and the dynamics of solutions of hard spheres (HS) in a solvent formed by Jagla ramp particles. We consider the cases of HS mole fraction x = 0.10, 0.15 and 0.20, and also the case x = 0.50 (a 1:1 mixture of HS and Jagla particles). We find a liquid-liquid critical point, up to the highest HS mole fraction; its position shifts to higher pressures and lower temperatures upon increasing x. We also find that the diffusion coefficient anomalies appear to be preserved for all the mole fractions studied.Comment: 8 pages, 7 figures, 1 table. In press (Phys. Rev. E

    The tower of London (tol) in Italy. standardization of the tol test in an Italian population

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    Deficit in planning and problem-solving, affecting a wide range of neuropsychological patients, has been widely investigated using the Tower of London (ToL) test, as developed by Shallice (Philos Trans R Soc Lond Ser B Biol Sci 298:199-209, 1). The ToL taps on several executive functions (EF), such as planning, time for planning or rule breaks, which may be usefully indexed by different ToL measurements. However, in its original version, the different aspects involved in ToL are not evaluated in a specific way.Here, we report the standardization of the ToL, on 896 individuals aged 15-86 years, taking in account individual factors (i.e. gender, age, years of education) which may affect performances on ToL. We computed several indexes on the ToL including score, planning and execution times, perseverations, rule breaks and self-monitoring. We found that these indexes were affected by individual factors such as gender, age and education. Present results not only provide extensive normative data according to gender, as well as different age and education ranges, but also represent a very useful instrument for a more fine-grained diagnosis of EF deficits in a wide range of neuropsychological patients, including traumatic brain injury and brain-damaged patients, as well as Alzheimer's disease and Parkinson's disease patients

    Spontaneous physical activity down-regulates Pax7 in cancer cachexia

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    Emerging evidence suggests that the muscle microenvironment plays a prominent role in cancer cachexia. We recently showed that NF-kB - induced Pax7 overexpression impairs the myogenic potential of muscle precursors in cachectic mice, suggesting that lowering Pax7 expression may be beneficial in cancer cachexia. We evaluated the muscle regenerative potential after acute injury in C26 colon carcinoma tumor-bearing mice and healthy controls. Our analyses confirmed that the delayed muscle regeneration observed in muscles form tumor-bearing mice was associated with a persistent local inflammation and Pax7 overexpression. Physical activity is known to exert positive effects on cachectic muscles. However, the mechanism by which a moderate voluntary exercise ameliorates muscle wasting is not fully elucidated. To verify if physical activity affects Pax7 expression, we hosted control and C26-bearing mice in wheel-equipped cages and we found that voluntary wheel running down-regulated Pax7 expression in muscles from tumor-bearing mice. As expected, down-regulation of Pax7 expression was associated with a rescue of muscle mass and fiber size. Our findings shed light on the molecular basis of the beneficial effect exerted by a moderate physical exercise on muscle stem cells in cancer cachexia. Furthermore, we propose voluntary exercise as a physiological tool to counteract the over-expression of Pax7observed in cancer cachexia

    Workability and chemical-physical degradation of limestone frequently used in historical Mediterranean architecture

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    Sedimentary rocks are among the most used in historical buildings, as they are more readily available in the area and because they are also more easily extractable, in virtue in general of lower mechanical resistance. among these the most used are limestones and sandstones. The former are represented by a remarkable variety of lithologies, with highly variable characteristics, passing from the almost pure, massive and not very porous limestones, to those with a variable arenaceous-clayey component which instead are characterized by a low compactness and consequent high porosity (up to 35%). In this study the calcarenites present in two geographic sectors of Sardinia are dealt with, by comparing them with similar showers present in other territorial contexts of the Mediterranean. The mineralogical-petrographic analyzes by optical microscope and XRD analysis of the "Pietra Cantone" limestone of Cagliari (south Sardinia) show, besides calcite, the presence of phyllosilicates and various other accessory minerals. SEM analyses show a very weak physical-mechanical microstructure
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