Non-equilibrium condensation and coarsening of field-driven dipolar colloids

In colloidal suspensions, self-organization processes can be easily fueled by external fields. One particularly interesting class of phenomena occurs in monolayers of dipolar particles that are driven by rotating external fields. Here we report results from a computer simulation study of such systems focusing on the clustering behavior also observed in recent experiments. The key result of this paper is a novel interpretation of this pattern formation phenomenon: We show the clustering to be a by-product of a vapor-liquid first order phase transition. In fact, the observed dynamic coarsening process corresponds to the spindodal demixing that occurs during such a transitionComment: 6 pages, 5 figure

HIV-assoziierte Malignome

Kaposi's sarcoma (KS), Non-Hodgkin's lymphma (NHL) and invasive cervical cancer are considered AIDS-defining malignancies. The incidence of Kaposi's sarcoma has recently been increased as a secondary manifestation of AIDS. The pathogenesis is not completely understood. Human herpesvirus 8 could be identified as an infectious cofactor. Therapeutic strategies should be based on prognostic factors and tailored to the patient's individual situation. Local treatments widely used are cryotherapy or radiotherapy. Systemic therapies such as interferon-alpha. or single and multiagent chemotherapy are also well established. Based on their high response rates and favorable toxicity profile, liposome-encapsulated anthracyclines may be considered first-line therapy for advanced AIDS-related KS. HIV-associated NHL may increase in frequency as HIV-infected individuals survive longer with improved antiretroviral therapy. There is no advantage for intensive as compared with standard or less intensive chemotherapeutic regimens of the CHOP type. Complete remissions can be achieved in approximately 50% of the patients, but the recurrence rate is high. The therapeutic strategy should include an optimal supportive care and antiretroviral treatment because chemotherapy significantly increases the risk of opportunistic infection. In urban populations at risk, cervical cancer is a common AIDS-related malignancy in women. Patients with cervical carcinoma usually have a more aggressive and more advanced disease. Various malignant diseases, such as Hodgkin's lymphoma, anal cancer or seminoma in patients with AIDS occur at higher frequency in HIV infection

Precursor and ambient rock paleothermometry to assess the thermicity of burial dolomitization in the southern Cantabrian Zone (northern Spain)

International audiencePaleozoic rocks in the Cantabrian Zone, and the Variscan foreland fold-and-thrust belt on the Iberian Peninsula have been affected by a sequence of diagenetic to epizonal thermal events. Late- to Post-Variscan hot fluid circulation caused a large-scale burial dolomitization and ore mineralization, mostly in Cambrian and a Lower to Middle Carboniferous carbonate sucessions. The goal of this study is to analyze and compare the temperatures experienced by the carbonate precursor rocks, as well as the under- and over-lying siliciclastic ambient rocks to gain a better understanding of the thermicity of dolomitization. These temperatures are evaluated based on published paleothermal datasets combined with new data obtained from Rock–Eval pyrolysis and vitrinite reflectance analysis of Carboniferous rocks rich in organic matter. The overall results indicate that reworking of detrital sediments in synorogenic ambient siliciclastics results in an anomalously high thermal maturity recorded by bulk rock techniques such as illite crystallinity and Rock–Eval pyrolysis. In situ VR-derived paleotemperatures recorded by ambient siliciclastic rocks appear to be higher compared to CAI-derived temperatures for carbonate precursor rocks. This variation in thermal maturity is likely related to the analytical techniques used to obtain CAI and VR data, and the empirical equations applied to calculate corresponding paleotemperatures. Conodont fragments were not as sensitive compared to vitrinite, and the color alteration process could have suffered from hydrothermal alteration. A secondary cause might be a different response to mechanical deformation between siliciclastic and carbonate units during the Variscan and post-Variscan geodynamic evolution of the study area. Rigid precursor carbonate units experienced fluid circulation mainly along distinct and spaced fracture zones, creating fracture-related dolomite geobodies and ore mineralization. Soft ambient siliciclastic rocks experienced more diffuse fluid circulation and heat dissipation. The different paleothermometry datasets compiled for the study area indicate that the fluids circulating during Late- to Post-Variscan times, with associated fracture-related dolomitization and ore mineralization in carbonate precursors, are hydrothermal. The highest paleotemperatures were recorded in ambient and precursor rocks in the highly tectonized northern part of the study area, where several thrusts and faults allowed intense fluid circulation. Positive temperature anomalies within the precursor carbonates correlate well with the occurrence of dolomite geobodies and ore mineral deposits. Such anomalies could thus be used as an exploration tool for hydrothermal dolomite bodies in analog sub-surface settings

Precision Calculations for Future Colliders

I discuss the motivations for, and the status of, precision calculations for the Large Hadron Collider (LHC) and the planned International Linear Collider (ILC).Comment: latex, uses ws-ijmpe.cls, 19 pages, 9 figures, 1 table, based on a talk given at the symposium "50 Years of High Energy Physics at UB", to appear in International Journal of Modern Physics

Strictly Toral Dynamics

This article deals with nonwandering (e.g. area-preserving) homeomorphisms of the torus $\mathbb{T}^2$ which are homotopic to the identity and strictly toral, in the sense that they exhibit dynamical properties that are not present in homeomorphisms of the annulus or the plane. This includes all homeomorphisms which have a rotation set with nonempty interior. We define two types of points: inessential and essential. The set of inessential points $ine(f)$ is shown to be a disjoint union of periodic topological disks ("elliptic islands"), while the set of essential points $ess(f)$ is an essential continuum, with typically rich dynamics (the "chaotic region"). This generalizes and improves a similar description by J\"ager. The key result is boundedness of these "elliptic islands", which allows, among other things, to obtain sharp (uniform) bounds of the diffusion rates. We also show that the dynamics in $ess(f)$ is as rich as in $\mathbb{T}^2$ from the rotational viewpoint, and we obtain results relating the existence of large invariant topological disks to the abundance of fixed points.Comment: Incorporates suggestions and corrections by the referees. To appear in Inv. Mat

On the relevance of polyynyl-substituted PAHs to astrophysics

We report on the absorption spectra of the polycyclic aromatic hydrocarbon (PAH) molecules anthracene, phenanthrene, and pyrene carrying either an ethynyl (-C2H) or a butadiynyl (-C4H) group. Measurements were carried out in the mid infrared at room temperature on grains embedded in CsI pellets and in the near ultraviolet at cryogenic temperature on molecules isolated in Ne matrices. The infrared measurements show that interstellar populations of polyynyl-substituted PAHs would give rise to collective features in the same way non-substituted PAHs give rise to the aromatic infrared bands. The main features characteristic of the substituted molecules correspond to the acetylenic CH stretching mode near 3.05 mum and to the almost isoenergetic acetylenic CCH in- and out-of-plane bending modes near 15.9 mum. Sub-populations defined by the length of the polyynyl side group cause collective features which correspond to the various acetylenic CC stretching modes. The ultraviolet spectra reveal that the addition of an ethynyl group to a non-substituted PAH molecule results in all its electronic transitions being redshifted. Due to fast internal energy conversion, the bands at shorter wavelengths are significantly broadened. Those at longer wavelengths are only barely affected in this respect. As a consequence, their relative peak absorption increases. The substitution with the longer butadiynyl chain causes the same effects with a larger magnitude, resulting in the spectra to show a prominent if not dominating pi-pi* transition at long wavelength. After discussing the relevance of polyynyl-substituted PAHs to astrophysics, we conclude that this class of highly conjugated, unsaturated molecules are valid candidates for the carriers of the diffuse interstellar bands.Comment: 29 pages, 9 figures, accepted for publication in ApJ 2 April 201

Development of an Antioxidative Pickering Emulsion Gel through Polyphenol-Inspired Free-Radical Grafting of Microcrystalline Cellulose for 3D Food Printing

The manufacture of next-generation 3D-printed foods with personalized requirements can be accelerated by in-depth knowledge of the development of a multifunctional biopolymeric-based ink. As a fat replacer in the food industry, microcrystalline cellulose (MCC) has the potential to address the growing need for sustainable healthy reduced-fat 3D printed foods. The modification of MCC structure by polyphenols gives the way to produce a multifunctional antioxidative Pickering emulsion with improved emulsifying properties. In this study, different types of polyphenols, including gallic acid (GA), tannic acid (TA), and cyanidin-3-O-glucoside (C3G), were individually used to synthesize the grafted MCC-g-polyphenol conjugates by the free-radical grafting method. Then, the antioxidative grafted microconjugates were added to a soy protein-based emulsion gel to partially substitute its oil, and each Pickering emulsion gel variant was printed through an extrusion-based 3D printing system. Emulsifying properties and antioxidant character of MCC were proven to be enhanced after the fabrication of grafted microconjugates. Compared to MCC-g-TA, MCC-g-GA and MCC-g-C3G could efficiently improve the stability of a reduced-fat soy-based emulsion gel upon storage. Moreover, the reduced-fat soy-based emulsion gel containing grafted microconjugates endowed a characteristic shear-thinning behavior with a gel-like structure and superlative thixotropic properties. Following the printing, the antioxidative Pickering emulsion gels containing grafted microconjugates produced well-defined 3D structures with superior lubrication properties. This study demonstrated that the grafting of polyphenols onto MCC could enhance bioactive properties and improve emulsifying performance of MCC, making it a useful component in the development of personalized functional foods

Application of Pickering emulsions in 3D printing of personalized nutrition. Part II: Functional properties of reduced-fat 3D printed cheese analogues

The current interest in personalized food through the application of surface-active biopolymers and additive manufacturing has identified a requirement to tailor a 3D printed healthy diet with well-defined geometries. In this study, a reduced-fat casein-based Pickering emulsion was stabilized via different ratios of acetylated microcrystalline cellulose, and then it was printed through an extrusion-based printer. The micro-biosurfactant contents led to differences in the printing performance and resolution of printed architectures. The original compact and uneven structures of 3D printed objects were reduced in presence of micro-biosurfactant, providing a uniform and porous matrix. Thermal investigation indicated that oil and aqueous phases in the reduced-fat 3D printed systems were less readily frozen. Proton molecular mobility became less mobile and moved to the populations with a shorter relaxation time upon micro-biosurfactant addition. Oral tribology was shown to depend on micro-biosurfactant content, where less deformable (firmer) 3D printed objects decreased surface-surface contact and reduced friction coefficients, improving lubrication property. The dynamic sensory evaluation by temporal dominance of sensations showed promising results regarding creaminess and mouth-coating, which was correlated well with instrumental readings. This work established an integrated attitude, from fundamental and practical viewpoints, supporting the application of Pickering emulsions in the 3D printing process to develop functional foods, broadening the micro-biosurfactant utilization in food printing