913 research outputs found
Negative thermal expansion
Materials with a negative thermal expansion coefficient contract when heated and expand when cooled. This paper reviews mechanisms of how this unusual property can be achieved at the molecular and macroscopic level. Some applications of this unusual property are also discussed.peer-reviewe
Capturing Multivariate Spatial Dependence: Model, Estimate and then Predict
Physical processes rarely occur in isolation, rather they influence and
interact with one another. Thus, there is great benefit in modeling potential
dependence between both spatial locations and different processes. It is the
interaction between these two dependencies that is the focus of Genton and
Kleiber's paper under discussion. We see the problem of ensuring that any
multivariate spatial covariance matrix is nonnegative definite as important,
but we also see it as a means to an end. That "end" is solving the scientific
problem of predicting a multivariate field. [arXiv:1507.08017].Comment: Published at http://dx.doi.org/10.1214/15-STS517 in the Statistical
Science (http://www.imstat.org/sts/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Photopyroelectric Investigation of the transâcis Isomerization Effect on the Nematic- Isotropic Phase Transition of a Liquid Crystalline Azobenzene
Photopyroelectric calorimetry has been applied to the study of the effects of different concentration of photo-induced cis isomeric molecules on the characteristics of the nematic â isotropic phase transition in p,pâ-diheptylazobenzene (7AB) samples. The investigations could be carried out by monitoring the behavior of the thermal diffusivity over the phase transition before and during the sample irradiation with UV light of varying intensity. Among other, it is shown that the monitoring of the time dependence of the thermal diffusivity at fixed sample temperature enabled the comparative study of the dynamics of the transâcis and cisâtrans isomeric transitions. It was shown that the increasing cis isomers concentration caused an increase in the fraction of material undergoing the phase transitions and increased the cisâtrans conversion rate. Finally, polarization microscopy observations of the sample texture, which could be carried out together with the calorimetric evaluations proved useful for a more comprehensive analysis of the obtained results
A system with adjustable positive or negative thermal expansion
We analyse the anisotropic thermal expansion properties of a two-dimensional structurally rigid construct made from rods of different materials connected together through hinges to form triangular units. In particular, we show that this system may be made to exhibit negative thermal expansion coefficients along certain directions or thermal expansion coefficients that are even more positive than any of the component materials. The end product is a multifunctional system with tunable thermal properties that can be tailor-made for particular practical applications.peer-reviewe
Constitutive expression of Yes-associated protein (Yap) in adult skeletal muscle fibres induces muscle atrophy and myopathy
Peer reviewedPublisher PD
Thermographic and reflectographic imaging investigations on Baroque paintings preserved at the Chigi Palace in Ariccia
In this work, two different mid-infrared imaging techniques operating in the 3-5 ÎŒm spectral range are applied to the study of three paintings on canvas, dating back to the XVII century, preserved at the Chigi Palace in Ariccia (Italy). A combined approach based on the use of pulsed thermography and mid-infrared reflectography is proposed for the analysis of the 'Primavera' by Filippo Lauri and Mario Nuzzi, the 'Ritratto di Mario Nuzzi che dipinge un vaso di fiori' by Giovanni Maria Morandi and Mario Nuzzi and the 'Ebbrezza di Noee' by Andrea Sacchi. The aim is to show how the integrated use of these techniques enables a depth-resolved investigation of the entire layered structure of the paintings, from the surface up to the canvas support. The complementarity of the presented results allows an evaluation of the conservative status of the support and the detection of graphical and pictorial features hidden beneath the surface layer, such as pentimenti, as these features are important for the historical and artistic characterisation of the artefact
Effects of diabetes family history and exercise training on the expression of adiponectin and leptin and their receptors
The daughters of patients with diabetes have reduced insulin sensitivity index (ISI) scores compared with women with no family history of
diabetes, but their ISI increase more in response to exercise training(1). The present study aimed to determine whether differences between
these groups in exercise-induced changes in circulating adiponectin and leptin concentrations and expression of their genes and receptors
in subcutaneous adipose tissue (SAT), could explain differences in the exercise-induced changes in ISI between women with and without
a family history of diabetes
E-heritage : the future for integrated applications in cultural heritage
A number of factors are combining to change the structure and contents of documentation of cultural heritage: 1) the exponential growth in data generated by imaging techniques makes it possible for a site or an artifact to be recorded at a resolution of over 16 megapixels and at a density of several hundred million cloud points; 2) high-resolution imaging is becoming more affordable and/or available; 3) the economics and legal constraints of conservation practice are gradually pushing towards more stringent documentation standards; 4) improved communications infrastructure and mobile computing facilities are changing the way that data is recorded, processed, stored and â inevitably - used; 5) increasingly available computerized expert systems will be integrated into the very systems that conservators and documentation specialists carry around with them or access on a daily basis; 6) the advent of web-based systems will afford super-computer processing power and large-system database handling to the documentation specialist and the conservator in the field and permit greater flexibility for teleworking; 7) Computerised Project-based Management techniques will gradually spread from the realm of large institutions to SMEâs and individual practitioners making digital image processing in architecture and archaeology more akin to the exchange of engineering drawings in automobile design industry. 8) The availability of cheap local or distributed processing power means that most of the above advantages will be present in both developed and developing countries. This paper explores. e-heritage as an integrated project which aims at providing a seamless yet structurally and inherently up-gradeable technological platform for all activities within cultural heritage conservation and management.peer-reviewe
Disturbed Sleep Connects Symptoms of Posttraumatic Stress Disorder and Somatization: A Network Analysis Approach
Posttraumatic stress disorder (PTSD) and physical health problems, particularly somatic symptom disorder, are highly comorbid. Studies have only examined this coâoccurrence at the disorder level rather than assessing the associations between specific symptoms. Using network analysis to identify symptoms that act as bridges between these disorders may allow for the development of interventions to specifically target this comorbidity. We examined the association between somatization and PTSD symptoms via network analysis. This included 349 traumaâexposed individuals recruited through the National Centre for Mental Health PTSD cohort who completed the ClinicianâAdministered PTSD Scale for DSMâ5 and the Patient Health Questionnaireâ15. A total of 215 (61.6%) individuals met the DSMâ5 diagnostic criteria for PTSD. An exploratory graph analysis identified four clusters of densely connected symptoms within the overall network: PTSD, chronic pain, gastrointestinal issues, and more general somatic complaints. Sleep difficulties played a key role in bridging PTSD and somatic symptoms. Our network analysis demonstrates the distinct nature of PTSD and somatization symptoms, with this association connected by disturbed sleep
Effect of X-ray and artificial aging on parchment
In this study, the employment of the X-ray irradiation as bioremediation method to treat parchment has been deeply investigated. In particular, the effect of the irradiation doses on the structural stability of collagen, the main constituent of parchment, has been evaluated on a series of modern parchment samples by means of different opto-thermal and spectroscopic techniques in order to obtain the dose-dependent effect of irradiation on collagen. Moreover, the long-term behavior of the irradiated parchment has been considered by analyzing the same series of samples after being hygrothermally artificially aged. Characterizations by light transmission analysis, Fourier transform infrared spectroscopy and the ultraviolet-visible-near infrared (UV-Vis-NIR) reflectance one have been performed for the identification of the radio-induced effect on the parchment structure even in a dose range much wider than the need for sterilization. The obtained results have proved the safeness of the method in the short and long term confirming the applicability of this emerging procedure
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