284 research outputs found
Fundamental partial compositeness
We construct renormalizable Standard Model extensions, valid up to the Planck
scale, that give a composite Higgs from a new fundamental strong force acting
on fermions and scalars. Yukawa interactions of these particles with Standard
Model fermions realize the partial compositeness scenario. Under certain
assumptions on the dynamics of the scalars, successful models exist because
gauge quantum numbers of Standard Model fermions admit a minimal enough 'square
root'. Furthermore, right-handed SM fermions have an SU(2)-like structure,
yielding a custodially-protected composite Higgs. Baryon and lepton numbers
arise accidentally. Standard Model fermions acquire mass at tree level, while
the Higgs potential and flavor violations are generated by quantum corrections.
We further discuss accidental symmetries and other dynamical features stemming
from the new strongly interacting scalars. If the same phenomenology can be
obtained from models without our elementary scalars, they would reappear as
composite states.Comment: 36 pages, 3 figures, 5 tables. v2: final published version, expanded
discussion about neutrino masses, dark matter and flavou
Naturalness of asymptotically safe Higgs
We extend the list of theories featuring a rigorous interacting ultraviolet
fixed point by constructing the first theory featuring a Higgs-like scalar with
gauge, Yukawa and quartic interactions. We show that the theory enters a
perturbative asymptotically safe regime at energies above a physical scale
. We determine the salient properties of the theory and use it as a
concrete example to test whether scalars masses unavoidably receive quantum
correction of order . Having at our dispose a calculable model
allowing us to precisely relate the IR and UV of the theory we demonstrate that
the scalars can be lighter than . Although we do not have an answer to
whether the Standard Model hypercharge coupling growth towards a Landau pole at
around GeV can be tamed by non-perturbative asymptotic
safety, our results indicate that such a possibility is worth exploring. In
fact, if successful, it might also offer an explanation for the unbearable
lightness of the Higgs.Comment: 17 pages. v2: final version; extra argument in the conclusions makes
obvious why our claims are correc
Real and Complex Fundamental Partial Compositeness
We complete the analysis of the effective field theory at the electroweak
scale for minimal models of fundamental partial compositeness. Specifically, we
consider fermions in the complex and real representation of the gauge group
underlying the composite Higgs dynamics, since the pseudo real representation
was investigated earlier. The minimal models feature the cosets
SU(4)xSU(4)/SU(4)_D and SU(5)/SO(5) respectively for the complex and real
representations. We determine the vacuum alignment, the electroweak precision
constraints, additional collider constraints. We finally discuss the main
differences among the different models of minimal partial compositeness.Comment: 31 pages, 1 Figure, 3 Table
Progress and Perspectives in the Management of Wound Infections
The progress in nanotechnology and the medical application of novel generations of nanomaterials have opened new horizons in the definition of non-conventional approaches against multiple diseases. Biomaterials coated with antimicrobial metal nanoparticles, along with the topical applications of zinc, silver or copper-based formulations have demonstrated huge potential in prevention from infections associated with implantable medical devices and in biofilm eradication. In wound healing, in particular, the increasing healthcare costs and the antibiotic resistance demonstrated by several microorganisms have encouraged researchers and companies in the development of innovative wound dressings with antibacterial properties and capability to promote and enhance the healing process. Supported by scientific evidence, many formulations have been proposed and a large number of works involves the use of hybrid metal nanoparticles/polymer products, which have demonstrated encouraging results both in vitro and in vivo. In this chapter, recent progress in the development of novel wound dressings based on antibacterial metal nanoparticles is presented, along with the most interesting results achieved by the authors, mainly devoted to the application of silver nanocoatings in wound management
Investigating the Structure-Related Properties of Cellulose-Based Superabsorbent Hydrogels
Superabsorbent hydrogels are macromolecular networks able to absorb and retain large amounts of water solutions within their fine mesh-like structure. More importantly, they are capable of multiple swelling/shrinking transitions in response to specific environmental cues (e.g., pH, ionic strength, temperature, presence of given electrolytes), thus exhibiting a stimuli-sensitive behavior, which makes them appealing for the design of smart devices in a number of technological fields. In particular, in the last two decades, cellulose-based superabsorbent hydrogels have proven to be an environmentally friendly and cost-effective alternative to acrylamide-based products. This chapter reviews the relationship between the molecular structure of cellulose-based hydrogels and their physicochemical properties. First, the network formation through the use of different cellulose derivatives and chemical or physical crosslinking agents is presented. Successively, the smart swelling capability of the hydrogels as a function of composition and structure is thoroughly discussed. Finally, several approaches to the hydrogel characterization are reviewed, with focus on the assessment of key mechanical, thermal and morphological properties
Current Trends in Gelatin-Based Drug Delivery Systems
Gelatin is a highly versatile natural polymer, which is widely used in healthcare-related sectors due to its advantageous properties, such as biocompatibility, biodegradability, low-cost, and the availability of exposed chemical groups. In the biomedical field, gelatin is used also as a biomaterial for the development of drug delivery systems (DDSs) due to its applicability to several synthesis techniques. In this review, after a brief overview of its chemical and physical properties, the focus is placed on the commonly used techniques for the development of gelatin-based micro- or nano-sized DDSs. We highlight the potential of gelatin as a carrier of many types of bioactive compounds and its ability to tune and control select drugs' release kinetics. The desolvation, nanoprecipitation, coacervation, emulsion, electrospray, and spray drying techniques are described from a methodological and mechanistic point of view, with a careful analysis of the effects of the main variable parameters on the DDSs' properties. Lastly, the outcomes of preclinical and clinical studies involving gelatin-based DDSs are thoroughly discussed
Mimicking the Hierarchical Organization of Natural Collagen: Toward the Development of Ideal Scaffolding Material for Tissue Regeneration
Biological materials found in living organisms, many of which are proteins, feature a complex hierarchical organization. Type I collagen, a fibrous structural protein ubiquitous in the mammalian body, provides a striking example of such a hierarchical material, with peculiar architectural features ranging from the amino acid sequence at the nanoscale (primary structure) up to the assembly of fibrils (quaternary structure) and fibers, with lengths of the order of microns. Collagen plays a dominant role in maintaining the biological and structural integrity of various tissues and organs, such as bone, skin, tendons, blood vessels, and cartilage. Thus, "artificial" collagen-based fibrous assemblies, endowed with appropriate structural properties, represent ideal substrates for the development of devices for tissue engineering applications. In recent years, with the ultimate goal of developing three-dimensional scaffolds with optimal bioactivity able to promote both regeneration and functional recovery of a damaged tissue, numerous studies focused on the capability to finely modulate the scaffold architecture at the microscale and the nanoscale in order to closely mimic the hierarchical features of the extracellular matrix and, in particular, the natural patterning of collagen. All of these studies clearly show that the accurate characterization of the collagen structure at the submolecular and supramolecular levels is pivotal to the understanding of the relationships between the nanostructural/microstructural properties of the fabricated scaffold and its macroscopic performance. Several studies also demonstrate that the selected processing, including any crosslinking and/or sterilization treatments, can strongly affect the architecture of collagen at various length scales. The aim of this review is to highlight the most recent findings on the development of collagen-based scaffolds with optimized properties for tissue engineering. The optimization of the scaffolds is particularly related to the modulation of the collagen architecture, which, in turn, impacts on the achieved bioactivity
High fiber cakes from mediterranean multipurpose oilseeds as protein sources for ruminants
Fifteen oilseed cakes from sunflower, pomegranate, cardoon, tobacco and hemp were characterized with regard to chemical composition, Cornell Net Carbohydrate and Protein System (CNCPS) fractionation, in vitro digestibility of dry matter, neutral detergent fiber, and crude protein. All the cakes presented low moisture, rather variable ether extract contents and medium to high levels of crude protein and neutral detergent fiber. The cakes significantly differed in terms of CNCPS partitioning and in vitro digestibility. Tobacco and hemp cakes presented high contents of slow degradable fractions of crude protein and carbohydrate joined to good post-ruminal protein digestibility. Cardoon cakes presented the highest rumen protein degradability. Based on crude protein content and intestinal digestibility of rumen undegraded protein, cakes of tobacco and hemp showed the better potential as alternative protein supplements for ruminants, while pomegranate appears to be the least suitable for ruminant feeding
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