90 research outputs found
Atomistic simulation of structure and dynamics of columnar phases of hexabenzocoronene derivatives
Using atomistic molecular dynamics simulations we study solid and liquid
crystalline columnar discotic phases formed by alkyl-substituted
hexabenzocoronene mesogens. Correlations between the molecular structure,
packing, and dynamical properties of these materials are established
Charge mobility of discotic mesophases: A multiscale quantum/classical study
A correlation is established between the molecular structure and charge
mobility of discotic mesophases of hexabenzocoronene derivatives by combining
electronic structure calculations, Molecular Dynamics, and kinetic Monte Carlo
simulations. It is demonstrated that this multiscale approach can provide an
accurate ab-initio description of charge transport in organic materials
Celiac Disease and Pediatric Type 1 Diabetes: Diagnostic and Treatment Dilemmas
Despite the advent
of sensitive and specific serologic testing,
routine screening for celiac disease (CD) in
diabetic populations may not be universal
practice, and many clinicians struggle to find
the optimal approach to managing CD in pediatric
Type 1 diabetes (T1D) patients. While some
clinicians advocate screening for CD in all
patients with T1D, others are unsure whether
this is warranted. The diagnosis of patients who
present with symptomatic CD, including
malabsorption and obvious pathology upon biopsy,
remains straightforward, with improvements noted
on a gluten-free diet. Many patients identified
by screening, however, tend to be asymptomatic.
Evidence is inconclusive as to whether the
benefits of screening and potentially treating
asymptomatic individuals outweigh the harms of
managing a population already burdened with a
serious illness. This review focuses on current
knowledge of CD in children and youth with T1D,
highlighting important elements of the
disease's pathophysiology, epidemiology,
clinical presentation, and diagnostic
challenges
Exploiting natural polysaccharides to enhance in vitro bio-constructs of primary neurons and progenitor cells
Current strategies in Central Nervous System (CNS) repair focus on the engineering of artificial scaffolds for guiding and promoting neuronal tissue regrowth. Ideally, one should combine such synthetic structures with stem cell therapies, encapsulating progenitor cells and instructing their differentiation and growth. We used developments in the design, synthesis, and characterization of polysaccharide-based bioactive polymeric materials for testing the ideal composite supporting neuronal network growth, synapse formation and stem cell differentiation into neurons and motor neurons. Moreover, we investigated the feasibility of combining these approaches with engineered mesenchymal stem cells able to release neurotrophic factors. We show here that composite bio-constructs made of Chitlac, a Chitosan derivative, favor hippocampal neuronal growth, synapse formation and the differentiation of progenitors into the proper neuronal lineage, that can be improved by local and continuous delivery of neurotrophins.
Statement of Significance
In our work, we characterized polysaccharide-based bioactive platforms as biocompatible materials for nerve tissue engineering. We show that Chitlac-thick substrates are able to promote neuronal growth, differentiation, maturation and formation of active synapses. These observations support this new material as a promising candidate for the development of complex bio-constructs promoting central nervous system regeneration. Our novel findings sustain the exploitation of polysaccharide-based scaffolds able to favour neuronal network reconstruction. Our study shows that Chitlac-thick may be an ideal candidate for the design of biomaterial scaffolds enriched with stem cell therapies as an innovative approach for central nervous system repair
Engineering of Three-Finger Fold Toxins Creates Ligands with Original Pharmacological Profiles for Muscarinic and Adrenergic Receptors
Protein engineering approaches are often a combination of rational design and directed evolution using display technologies. Here, we test âloop grafting,â a rational design method, on three-finger fold proteins. These small reticulated proteins have exceptional affinity and specificity for their diverse molecular targets, display protease-resistance, and are highly stable and poorly immunogenic. The wealth of structural knowledge makes them good candidates for protein engineering of new functionality. Our goal is to enhance the efficacy of these mini-proteins by modifying their pharmacological properties in order to extend their use in imaging, diagnostics and therapeutic applications. Using the interaction of three-finger fold toxins with muscarinic and adrenergic receptors as a model, chimeric toxins have been engineered by substituting loops on toxin MT7 by those from toxin MT1. The pharmacological impact of these grafts was examined using binding experiments on muscarinic receptors M1 and M4 and on the α1A-adrenoceptor. Some of the designed chimeric proteins have impressive gain of function on certain receptor subtypes achieving an original selectivity profile with high affinity for muscarinic receptor M1 and α1A-adrenoceptor. Structure-function analysis supported by crystallographic data for MT1 and two chimeras permits a molecular based interpretation of these gains and details the merits of this protein engineering technique. The results obtained shed light on how loop permutation can be used to design new three-finger proteins with original pharmacological profiles
TRY plant trait database â enhanced coverage and open access
Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of traitâbased plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for âplant growth formâ. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and traitâenvironmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
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