Extended corresponding-states behavior for particles with variable range attractions

We propose an extension of the law of corresponding states that can be applied to systems - such as colloidal suspensions - that have widely different ranges of attractive interactions. We argue that, for such systems, the ``reduced'' second virial coefficient is a convenient parameter to quantify the effective range of attraction. This procedure allows us to give a simple definition of the effective range of attraction of potentials with different functional forms. The advantage of the present approach is that it allows us to estimate the relative location of the liquid-vapor and solid-fluid coexistence curves exclusively on basis of the knowledge of the pair-potential.Comment: REVTeX, 5 pages, 2 figure

Metabarcoding analysis of the bacterial and fungal communities during the maturation of Preparation 500, used in biodynamic agriculture, suggests the rational link between horn and manure

10doi: 10.20944/preprints202008.0727.v1openInternational coauthor/editorHorn manure (Preparation 500) is a product used in the practice of biodynamic agriculture. It is obtained by an underground fermentation of cow faecal material incubated in cow horns for several months. The product is used as spray treatment meant to increase soil fertility. In the present report we analyzed the successional changes in bacterial and fungal communities throughout the process of horn manure maturation by high throughput sequencing of ribosomal 16S (bacterial) and ITS (fungal) gene markers. Marked shifts in the microbial community were seen involving a general decrease from a Firmicutes-dominated material to a product transiently enriched in Proteobacteria and later in Actinobacteria, mostly within the Nocardioidaceae family. In the fungal community evolution, the most abundant taxon in the starting faecal material resulted a member of the Onygenales order, known to specifically degrade keratin. Its abundance in the intestine is explained by the fact that keratin, which is also the structural component of hairs and horns, is found in all epithelial layers, including gut mucosae. This occurrence suggests a link of enzymatic/catabolic nature between manure and horn.openZanardo, Marina; Giannattasio, Matteo; Sablok, Gaurav; Pindo, Massimo; La Porta, Nicola; Lorenzetti, Michele; Noro, Carlo; Stevanato, Piergiorgio; Concheri, Giuseppe; Squartini, AndreaZanardo, M.; Giannattasio, M.; Sablok, G.; Pindo, M.; La Porta, N.; Lorenzetti, M.; Noro, C.; Stevanato, P.; Concheri, G.; Squartini, A

The role of long-range forces in the phase behavior of colloids and proteins

The phase behavior of colloid-polymer mixtures, and of solutions of globular proteins, is often interpreted in terms of a simple model of hard spheres with short-ranged attraction. While such a model yields a qualitative understanding of the generic phase diagrams of both colloids and proteins, it fails to capture one important difference: the model predicts fluid-fluid phase separation in the metastable regime below the freezing curve. Such demixing has been observed for globular proteins, but for colloids it appears to be pre-empted by the appearance of a gel. In this paper, we study the effect of additional long-range attractions on the phase behavior of spheres with short-ranged attraction. We find that such attractions can shift the (metastable) fluid-fluid critical point out of the gel region. As this metastable critical point may be important for crystal nucleation, our results suggest that long-ranged attractive forces may play an important role in the crystallization of globular proteins. However, in colloids, where refractive index matching is often used to switch off long-ranged dispersion forces, gelation is likely to inhibit phase separation.Comment: EURO-LATEX, 6 pages, 2 figure

Lamellar and inverse micellar structures of skin lipids: Effect of templating

The outermost layer of skin, the stratum corneum (SC), comprises rigid corneocytes in a layered lipid matrix. Using atomistic simulations we find that the equilibrium phase of the SC lipids is inverse micellar. A model of the corneocyte is used to demonstrate that lamellar layering is induced by the patterned corneocyte wall. The inverse micellar phase is consistent with in vivo observations in the lacunar spaces and at the stratum granulosum - SC boundary region, and suggests a functional role in the lipid synthesis pathway in vivo.Comment: pdflatex 5 pages, 10 page supplementary material. Published Physical Review Letters. Added link to website with animation

Advancements in hybrid photovoltaic-thermal systems: performance evaluations and applications

Due to European Directives (2010/31/UE on buildings energy performance, 2009/28/CE on the use of renewable energy, 2012/27/UE on the energy efficiency) the electric and thermal energy needs of new and retrofitted buildings are faced by increasing percentages of renewable energy. Solar energy and heat pumps are the most promising technologies mainly in residential buildings as they have reached great maturity. Anyway, in most cases solar energy utilizations systems are thermal (which convert solar energy to thermal energy) and photovoltaic (which convert solar energy to electricity) used as separated collectors. Commercial photovoltaic modules have nowadays an efficiency around 15 % - 18 %. It means that the most relevant part of solar radiation is lost. Such a remark gets more importance if the active surface is located in an urban environment, where the availability of surfaces exposed to the sun is scarce if compared to the buildings thermal loads. PhotoVoltaic / Thermal cogeneration (PV/T) aims to utilize the same area both for producing electricity and heat. As solar cells are sensitive to temperature (their efficiency lowers when temperature increases), heat is beneficially collected but it cannot be available at high temperatures. Many researches on performances and characteristics of different hybrid photovoltaic\u2013thermal technologies and systems have been carried out during the last years to face this problem; among these designs, systems utilizing air, liquid, heat pipes, phase change materials, and thermoelectric devices to aid cooling of PV cells. This paper provides a description of the applications of the photovoltaic\u2013thermal systems, such as building integrated PV/T, concentrating PV/T systems and photovoltaic\u2013thermal heat pump systems. Several factors affecting the performances and characteristics of the photovoltaic\u2013thermal systems are also summarized

Are you sitting comfortably? The political economy of the body

The aim of this paper is to examine the relationship between the mass production of furniture in modern industrial societies and lower back pain (LBP). The latter has proven to be a major cost to health services and private industry throughout the industrialised world and now represents a global health issue as recent WHO reports on obesity and LBP reveal. Thus far there have been few co-ordinated attempts to deal with the causes of the problem through public policy. Drawing upon a range of sources in anthropology, health studies, politics and economics, the paper argues that this a modern social problem rooted in the contingent conjuncture of natural and social causal mechanisms. The key question it raises is: what are the appropriate mechanisms for addressing this problem? This paper develops an analysis rooted in libertarian social theory and argues that both the state and the capitalist market are flawed mechanisms for resolving this problem. There remains a fundamental dilemma for libertarians, however. Whilst the state and the market may well be flawed mechanisms, they are the dominant ones shaping global political economy. To what extent can libertarians work within these structures and remain committed to libertarian goals

Thin Ice Target for 16^{16}O(p,p') experiment

A windowless and self-supporting ice target is described. An ice sheet with a thickness of 29.7 mg/cm$^2$ cooled by liquid nitrogen was placed at the target position of a magnetic spectrometer and worked stably in the $^{16}$O$(p,p')$ experiment at $E_{p}=392$ MeV. Background-free spectra were obtained.Comment: 14 pages, 4 figures, Nucl. Instr. & Meth. A (in press