620 research outputs found
Anarchic Yukawas and top partial compositeness: the flavour of a successful marriage
The top quark can be naturally singled out from other fermions in the
Standard Model due to its large mass, of the order of the electroweak scale. We
follow this reasoning in models of pseudo Nambu Goldstone Boson composite
Higgs, which may derive from an underlying confining dynamics. We consider a
new class of flavour models, where the top quark obtains its mass via partial
compositeness, while the lighter fermions acquire their masses by a deformation
of the dynamics generated at a high flavour scale. One interesting feature of
such scenario is that it can avoid all the flavour constraints without the need
of flavour symmetries, since the flavour scale can be pushed high enough. We
show that both flavour conserving and violating constraints can be satisfied
with top partial compositeness without invoking any flavour symmetry for the
up-type sector, in the case of the minimal SO(5)/SO(4) coset with top partners
in the four-plet and singlet of SO(4). In the down-type sector, some degree of
alignment is required if all down-type quarks are elementary. We show that
taking the bottom quark partially composite provides a dynamical explanation
for the hierarchy causing this alignment. We present explicit realisations of
this mechanism which do not require to include additional bottom partner
fields. Finally, these conclusions are generalised to scenarios with
non-minimal cosets and top partners in larger representations.Comment: 37 pages, 1 figure, v2: typos fixed, Eq. (3.44) added, version
corresponds to published article in JHE
Earthworm as an alternative protein source in poultry and fish farming : Current applications and future perspectives
Among the different agricultural activities, the livestock is one of the most impacting on the environment. The feeding of animals is often the main responsible of the adverse environmental impact related to animal productions. Above all for intensive production, the consumption of protein feed is a key aspect for the achievement of sustainable production processes. The actual consumption of soybean meal and fish meal is not sustainable due to the related environmental impact and to the increasing prices. Among the different alternative protein sources, in the last 20 years, the attention of research centres and private companies focused on insects, algae and other invertebrates but, up to now, little consideration was paid to the use of fresh earthworm or earthworm meal as a protein feed for monogastric animals. The use of earthworms as an alternative protein source for fish and poultry feeding is an opportunity for providing environmental services via cleaner technologies. Thanks to earthworms, organic wastes and by-products generated by livestock activities can be valorised and become a resource for animal feeding in a circular perspective. In this context, this manuscript was designed to summarize the productivity, suitability and effectiveness issues connected with the utilization of earthworms as alternative protein feed in poultry production as well as in aquaculture. The studies investigating the earthworm meal use are quite old above all those carried out in Europe; however, some general indications can be drawn: both for broiler and fish, the parameters usually evaluated are body weight gain, growth rate, feed intake and feed conversion rate, the acceptability level of earthworm meal in broiler diet is lower than 15% while in trout diet ranges between 25 and 30%. The inclusion of earthworm meal in diets with an inclusion level lower than the acceptability threshold allows good productive performances without affecting the quality of the final food products
Issues Facing Design Professionals through the Lens of Two Rain-Induced Roof Collapses
The drainage of low-sloped roof systems involves multiple design professionals, and often each has a different opinion as to their design responsibility. Roofing issues have been identified as being a number one source of litigation, and rain-induced roof collapses continue to occur with alarming frequency. With the backdrop of several rain-induced roof collapses, this paper illustrates the complexity of assigning design responsibility for drainage systems; and investigates a variety of outcomes associated with the current building code provisions transporting rainwater from large low-sloped roof structures
Communication: Free energy of ligand-receptor systems forming multimeric complexes.
Ligand-receptor interactions are ubiquitous in biology and have become popular in materials in view of their applications to programmable self-assembly. Although complex functionalities often emerge from the simultaneous interaction of more than just two linker molecules, state of the art theoretical frameworks enable the calculation of the free energy only in systems featuring one-to-one ligand/receptor binding. In this Communication, we derive a general formula to calculate the free energy of systems featuring simultaneous direct interaction between an arbitrary number of linkers. To exemplify the potential and generality of our approach, we apply it to the systems recently introduced by Parolini et al. [ACS Nano 10, 2392 (2016)] and Halverson and Tkachenko [J. Chem. Phys. 144, 094903 (2016)], both featuring functionalized Brownian particles interacting via three-linker complexes.LDM and LP acknowledge support from the EPSRC Programme Grant CAPITALS number EP/J017566/1. LDM acknowledges support from the Oppenheimer Fund and Emmanuel College Cambridge. SB and BMM are supported by the Universit´e Libre de Bruxelles (ULB)
Volume and porosity thermal regulation in lipid mesophases by coupling mobile ligands to soft membranes
Short DNA linkers are increasingly being exploited for driving specific
self-assembly of Brownian objects. DNA-functionalised colloids can assemble
into ordered or amorphous materials with tailored morphology. Recently, the
same approach has been applied to compliant units, including emulsion droplets
and lipid vesicles. The liquid structure of these substrates introduces new
degrees of freedom: the tethers can diffuse and rearrange, radically changing
the physics of the interactions. Unlike droplets, vesicles are extremely
deformable and DNA-mediated adhesion causes significant shape adjustments. We
investigate experimentally the thermal response of pairs and networks of
DNA-tethered liposomes and observe two intriguing and possibly useful
collective properties: negative thermal expansion and tuneable porosity of the
liposome networks. A model providing a thorough understanding of this
unexpected phenomenon is developed, explaining the emergent properties out of
the interplay between the temperature-dependent deformability of the vesicles
and the DNA-mediated adhesive forces.Funding was provided by the Ernest Oppenheimer Fund and Emmanuel College Cambridge (L.D.M.), EPSRC Programme Grant CAPITALS number EP/J017566/1 (L.P., J.K., P.C. and L.D.M.) and the Winton Fund for Physics of Sustainability (E.E.).This article was originally published in Nature Communications (L Parolini, BM Mognetti, J Kotar, E Eiser, P Cicuta, L Di Michele, Nature Communications 2015, 6, 5948
Multiphysics simulation of corona discharge induced ionic wind
Ionic wind devices or electrostatic fluid accelerators are becoming of
increasing interest as tools for thermal management, in particular for
semiconductor devices. In this work, we present a numerical model for
predicting the performance of such devices, whose main benefit is the ability
to accurately predict the amount of charge injected at the corona electrode.
Our multiphysics numerical model consists of a highly nonlinear strongly
coupled set of PDEs including the Navier-Stokes equations for fluid flow,
Poisson's equation for electrostatic potential, charge continuity and heat
transfer equations. To solve this system we employ a staggered solution
algorithm that generalizes Gummel's algorithm for charge transport in
semiconductors. Predictions of our simulations are validated by comparison with
experimental measurements and are shown to closely match. Finally, our
simulation tool is used to estimate the effectiveness of the design of an
electrohydrodynamic cooling apparatus for power electronics applications.Comment: 24 pages, 17 figure
Intra and inter-day repeatability of peripheral arterial function: suitability and potential limitations
The present study aimed to investigate the inter- and intraday repeatability of reactive hyperemia index (RHI) measured by Endo-PAT in healthy volunteers. Interday RHI repeatability was tested in two consecutive days in a group of thirty-one male subjects. Intraday repeatability was investigated at baseline and after 2 and 4 h in a group of sixteen volunteers. Data were evaluated by analysis of variance. Bland-Altman plot, coefficient of variation (CV), coefficient of repeatability (CR) and intraclass correlation coefficient (ICC) were measured. While interday RHI repeatability was found to be reliable (CV: 6.0%; CR: 0.51; ICC: 0.77), multiple evaluations within the same day significantly (p<0.001) affected RHI (repeatability of the measurement - CV: 18.8%; CR: 1.26; ICC: 0.48). In particular, a significant increase in RHI occurred at 4 h compared to 2 h (+16.8%; p<0.05) and to baseline (+30.1%; p<0.05). In conclusion, RHI showed good interday but poor intraday repeatability. Multiple evaluations increased RHI especially in subjects with endothelial dysfunction who improved or reversed their impairment. These results show the potential limitations of multiple Endo-PAT measurements within the same day and the importance of standardizing the protocols before RHI evaluations
A serving of blueberry (V. corymbosum) acutely improves peripheral arterial dysfunction in young smokers and non-smokers : two randomized, controlled, crossover pilot studies
Several studies have documented the important role of polyphenol-rich foods in the modulation of vascular remodelling and function. This study aimed to evaluate the capacity of a single portion of blueberry (V. corymbosum) to acutely improve peripheral arterial dysfunction in a group of young volunteers. Twenty-four healthy males (12 non-smokers and 12 smokers) were recruited for two different randomized, controlled, crossover pilot acute studies. In the first study, non-smokers were exposed to a control treatment (C; 300 mL of water with sugar) and a blueberry treatment (BB; 300 g of blueberry). In the second study, smokers underwent 3 different protocols: (1) - smoking treatment (S); (2) - control treatment (CS; 300 mL of water with sugar + smoking); (3) - blueberry treatment (BS; 300 g of blueberry + smoking). Each treatment (1 day long) was separated by a one week washout period. Blood pressure, peripheral arterial function (reactive hyperemia index, RHI, a marker of endothelial function) and arterial stiffness (digital augmentation index, dAix and dAix normalized by considering a heart rate of 75 bpm, dAix@75) were measured before and after each treatment. In the first study, the consumption of blueberry and control treatment acutely increased peripheral arterial function in the group of non-smokers. The improvement in RHI was higher and significantly different after blueberry treatment compared to the control treatment (54.8 \ub1 8.4% BB vs. 28.2 \ub1 8.3% C; p = 0.01). No effects were observed for markers of arterial stiffness, blood pressure and heart rate. Acute cigarette smoke significantly increased blood pressure and heart rate, while no significant effect was registered in peripheral arterial function and stiffness. The intake of blueberry and control treatment before a cigarette did not counteract the increase in blood pressure and heart rate, while it significantly improved peripheral arterial function. In particular, a significant increase was observed following BS (35.2 \ub1 7.5% RHI; p = 0.02) and CS treatments (34.6 \ub1 11.9% RHI; p = 0.02) when compared to only smoking treatment. No difference between BS and CS was detected. In conclusion, the intake of blueberry and control treatments acutely improved peripheral arterial dysfunction both in smoker and in non-smoker subjects. Further studies should be performed to confirm the results obtained and reveal the potential mechanisms of blueberry in the improvement of endothelial function
Enzymatically active apurinic/apyrimidinic endodeoxyribonuclease 1 is released by mammalian cells through exosomes
The apurinic/apyrimidinic endodeoxyribonuclease 1 (APE1), the main AP-endonuclease of the DNA base excision repair pathway, is a key molecule of interest to researchers due to its unsuspected roles in different nonrepair activities, such as: I) adaptive cell response to genotoxic stress, ii) regulation of gene expression, and iii) processing of microRNAs, which make it an excellent drug target for cancer treatment. We and others recently demonstrated that APE1 can be secreted in the extracellular environment and that serum APE1 may represent a novel prognostic biomarker in hepatocellular and non-smallcell lung cancers. However, the mechanism by which APE1 is released extracellularly was not described before. Here, using three different approaches for exosomes isolation: Commercial kit, nickel-based isolation, and ultracentrifugation methods and various mammalian cell lines, we elucidated the mechanisms responsible for APE1 secretion. We demonstrated that APE1 p37 and p33 forms are actively secreted through extracellular vesicles (EVs), including exosomes from different mammalian cell lines. We then observed that APE1 p33 form is generated by proteasomal-mediated degradation and is enzymatically active in EVs. Finally, we revealed that the p33 form of APE1 accumulates in EVs upon genotoxic treatment by cisplatin and doxorubicin, compounds commonly found in chemotherapy pharmacological treatments. Taken together, these findings provide for the first time evidence that a functional Base Excision Repair protein is delivered through exosomes in response to genotoxic stresses, shedding new light into the complex noncanonical biological functions of APE1 and opening new intriguing perspectives on its role in cancer biology
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