Polysaccharides are natural polymers with hydrophilic, biocompatible and biodegradable characteristics and have many opportunities in the food and pharmaceutical sectors. This review focuses on the ...field of nano and microstructures whose internal structure is based on networked polysaccharide chains in 3D i.e., polysaccharide nanogels (NGs) and microgels (MGs). As it is observed the number of articles on NGs and MGs in peer reviewed scientific journals has been increasing over the last two decades. At the same time, the relative contribution of polysaccharides in this field is gaining place. This review focuses on the different applied methods for the fabrication of a variety of polysaccharide-based NGs and MGs and aims to highlight the recent advances on the subject and present their potentials and properties with regards to their integration in aspects of medicinal and food sciences. The presentation of the recent advances in the application of polysaccharide NGs and MGs is divided in materials with potential as emulsion stabilizers and materials with potential as carriers of bioactives. For applications in the medical sector the division is based on the fabrication processes and includes self-assembled, electrostatically complexed/ionically crosslinked and chemically crosslinked NGs and MGs. It is concluded that many advances are expected in the application of these polysaccharide-based materials and in particular as nutrient-loaded emulsion stabilizers, viscosity modifiers and co-assembled structures in combination with proteins.
Polysaccharide materials and biomaterials gain the focus of intense research owing to their great versatility in chemical structures and modification possibilities, as well as their biocompatibility, ...degradability, and sustainability features. This review focuses on the recent advances in the application of SANS on polysaccharide systems covering a broad range of materials such as nanoparticulate assemblies, hydrogels, nanocomposites, and plant-originating nanostructured systems. It motivates the use of SANS in its full potential by demonstrating the features of contrast variation and contrast matching methods and by reporting the methodologies for data analysis and interpretation. As these soft matter systems may be organized in multiple length scales depending on the interactions and chemical bonds between their components, SANS offers exceptional and unique opportunities for advanced characterization and optimization of new nanostructured polysaccharide materials.
We use particle tracking microrheology to obtain the power-law dynamical behaviour of xanthan in several aqueous solution conditions and illustrate that the probe particle motion is subdiffusive even ...at low xanthan concentrations. Analysis of the concentration dependence of xanthan’s viscoelasticity is described in terms of linear and comb polyelectrolyte rheological models. There is a clear distinction between two power-law regimes i.e. unentangled and entangled of the modulus prefactor as a function of concentration. The critical entanglement concentration and the power-law exponents are investigated in terms of their dependence on the content and valency of the added salts. Above the entanglement concentration the deviation of the particles motion from Brownian diffusion depends strongly on concentration. Linear complex viscosity is compared to nonlinear steady shear rate viscosity in an illustration of predicting the nonlinear rheology from particle tracking measurements in food biopolymer solutions. Finally in renatured xanthan solutions the viscoelasticity enhancement by temperature treatment is demonstrated to be more effective in the entangled region.
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•Video particle tracking microrheology showed power-law behaviour for xanthan.•Two power-law regimes in concentration are observed i.e. unentangled and entangled.•Effects of content and valency of added salts are tested.•Complex viscosity is compared to the steady shear rate viscosity.•Renatured xanthan solutions are tested by temperature treatments.
In this paper, we present a novel data clustering framework for big sensory data produced by IoT applications. Based on a network representation of the relations among multi-dimensional data, data ...clustering is mapped to node clustering over the produced data graphs. To address the potential very large scale of such datasets/graphs that test the limits of state-of-the-art approaches, we map the problem of data clustering to a community detection one over the corresponding data graphs. Specifically, we propose a novel computational approach for enhancing the traditional Girvan-Newman (GN) community detection algorithm via hyperbolic network embedding. The data dependency graph is embedded in the hyperbolic space via Rigel embedding, allowing more efficient computation of edge-betweenness centrality needed in the GN algorithm. This allows for more efficient clustering of the nodes of the data graph in terms of modularity, without sacrificing considerable accuracy. In order to study the operation of our approach with respect to enhancing GN community detection, we employ various representative types of artificial complex networks, such as scale-free, small-world and random geometric topologies, and frequently-employed benchmark datasets for demonstrating its efficacy in terms of data clustering via community detection. Furthermore, we provide a proof-of-concept evaluation by applying the proposed framework over multi-dimensional datasets obtained from an operational smart-city/building IoT infrastructure provided by the Federated Interoperable Semantic IoT/cloud Testbeds and Applications (FIESTA-IoT) testbed federation. It is shown that the proposed framework can be indeed used for community detection/data clustering and exploited in various other IoT applications, such as performing more energy-efficient smart-city/building sensing.
To determine whether insulin action on endothelial cells promotes or protects against atherosclerosis, we generated apolipoprotein E null mice in which the insulin receptor gene was intact or ...conditionally deleted in vascular endothelial cells. Insulin sensitivity, glucose tolerance, plasma lipids, and blood pressure were not different between the two groups, but atherosclerotic lesion size was more than 2-fold higher in mice lacking endothelial insulin signaling. Endothelium-dependent vasodilation was impaired and endothelial cell VCAM-1 expression was increased in these animals. Adhesion of mononuclear cells to endothelium in vivo was increased 4-fold compared with controls but reduced to below control values by a VCAM-1-blocking antibody. These results provide definitive evidence that loss of insulin signaling in endothelium, in the absence of competing systemic risk factors, accelerates atherosclerosis. Therefore, improving insulin sensitivity in the endothelium of patients with insulin resistance or type 2 diabetes may prevent cardiovascular complications.
► Insulin decreases VCAM-1 protein expression in endothelial cells ► Knockout of endothelial insulin receptors increases leukocyte adhesion by 4-fold ► Loss of insulin signaling causes increase in atherosclerotic lesion area by >2-fold
•Semidilute xanthan solutions were studied by scattering methods.•Self-similarity was observed by power-law behaviour in dynamic light scattering.•Small angle neutron scattering revealed multiscale ...organization.•Molecular mass per unit length was measured by small angle neutron scattering.•No alignment of xanthan molecules was observed up to shear rate 1000rad/s.
The hierarchical morphology of xanthan solutions is analyzed by light and neutron scattering in a broad range of concentrations in order to connect their morphology to their well-documented dynamic properties. Static light scattering inside the semidilute regime is dominated by the form factor of individual xanthan chains while at higher concentrations chain interconnections appear to modify the low wave vector scattering. Dynamic light scattering reveals the self-similar nature of the solutions caused by interchain associations as intensity autocorrelation functions present power-law behaviour. Small angle neutron scattering is dominated by the fractal scattering from the formed network at intermediate length scales. At small length scales the rigid structure of xanthan is revealed and the molecular weight per unit length is extracted. No detectable morphological alterations for shear rates up to 1000rad/s are observed revealing that the shear thinning behaviour of xanthan is related to the disruption of chain-chain associations.
Sotiropoulos, K, Smilios, I, Barzouka, K, Christou, M, Bogdanis, G, Douda, H, and Tokmakidis, SP. Effects of drop jump training from different heights and weight training on vertical jump, maximum ...strength and change of direction performance in female volleyball players. J Strength Cond Res 37(2): 423-431, 2023-This study compared the effects of drop jump (DJ) training from different drop heights and weight training on vertical jump and maximum strength performance. Fifty-five female volleyball players (age: 23.8 ± 4.3 years) were randomly and equally allocated to a control group (volleyball training, CG); a volleyball and weight training group (WG); and 3 volleyball, weight, and drop jump training groups. One group performed DJ training from the optimal drop height, i.e., the height that elicited the highest ratio of jump height to contact time (OG), a second group from a drop height 25% higher than the optimal (HG), and a third group from a drop height 25% lower than the optimal (LG). Drop jump and weight training were performed 1-2 times per week, for 8 weeks for a total of 13 sessions. After training, vertical jump performance improved by 3.6-17.4% ( p < 0.05; effect size ES: 1.03-1.23) in the OG and the HG compared with the LG, WG, and CG ( p < 0.05; ES: 0.03-0.58). Drop jump height from drop heights 20-70 cm increased by 10.0-20.2% ( p < 0.05; ES: 0.59-1.13) for the OG and the HG, while reactive strength index increased ( p < 0.05; ES: 0.74-1.40) by 19.6-33.9% only in the HG compared with the CG. Half-squat maximum strength was increased in all experimental groups by 17.4-19% compared with the CG ( p < 0.05) with no differences ( p > 0.05) observed among them. The use of the optimal height or a moderately higher drop height by 25% for DJ training, combined with weight training, seems to be the most beneficial option to improve vertical jump and reactive strength index in female volleyball players.
Aim: To assess the role of the Balkan Peninsula as a Pleistocene refugium for the smooth newt, Lissotriton vulgaris, and to test whether its genetic differentiation is temporally compatible with the ...southern réfugia model. Location: The Balkan Peninsula. Methods: Phylogeographical analyses were conducted using mitochondrial DNA (mtDNA) sequences sampled from 49 populations of L.vulgaris. A fossil-calibrated estimate of divergence times among major mtDNA clades was obtained. Results: We detected seven parapatrically distributed mtDNA clades with very little admixture among populations. Whereas most clades diverged in the Pleistocene, the earliest splits between Caucasian, Anatolian and Balkan clades occurred in the Pliocene. Clades C, D, K and M have local distributions within the Balkans and have evolved in isolation from other groups. Clade L originated in the Pannonian Basin and northern margin of the Balkan Peninsula and recently expanded across central and western Europe. Clades H and E have recently arrived in the Balkans from source populations in the Apennine Peninsula and Anatolia, respectively. Main conclusions: The history of L. vulgaris involves multiple, independent refugiai populations in the Balkans. Only one of them, located at the northern periphery of the peninsula, showed evidence of post-glacial expansion into western and northern Europe. The Balkans have therefore served as a reservoir of old diversity for L. vulgaris. By contrast, populations at the northern and eastern frontiers of the peninsula have experienced non-equilibrium dynamics. Our dating revealed that very little, if any, pre-Pliocene genetic diversity has survived in Europe, despite an extensive fossil record for this species in the Miocene and Pliocene. Differentiation of the European mtDNA clades thus seems to have been primarily moulded by Pleistocene climate change. None of the currently recognized subspecies present in the Balkans are reciprocally monophyletic in their mtDNA. We hypothesize that incomplete lineage sorting and mtDNA introgression account for the observed discrepancies.
Aquatic invaders often cause severe declines of native amphibian populations, either through competition, predation and/or alterations of the habitat. Such situation has raised additional concerns ...for the persistence of endemic species exhibiting rare and alternative phenotypes. Here, we experimentally assessed the impact of the invasive mosquitofish (
Gambusia holbrooki
) on adult newts (
Lissotriton graecus
) exhibiting paedomorphosis, the retention of larval traits such as gills, making them fully aquatic. Mosquitofish had a negative impact on paedomorphic newts by inducing both behavioral and phenotypic changes. Paedomorphic newts exhibited avoidance behavior and higher metamorphosis rates in the presence of fish. Both female and male newts responded by decreasing mobility and foraging activity. Females stopped investing in egg-laying in presence of fish and males metamorphosed earlier than females. Hence, our results show that mosquitofish introductions, particularly in areas with populations exhibiting paedomorphosis, might have detrimental consequences on the preservation of alternative developmental pathways. Both behavioral and phenotypic effects should be assessed to understand the impacts of introduced species.
Assessing the variation in diet composition of a species, over different years and between periods, offers insights to comprehend its ecological niche as well as to define different feeding ...strategies. We studied the diet of the Lesser Kestrel (Falco naumanni) by analysing 1040 regurgitated pellets collected in the city of Ioannina (northwestern Greece). We compared diet composition between the breeding period (data from years 2010–2015) and the pre-migration period (data from 2013–2015) at the study site. A total of 8920 prey items were identified and classified into 13 different prey families. The Lesser Kestrel shows a consistent pattern of diet composition throughout years, displaying significant differences between breeding and pre-migration periods. The diet is rather diverse during the breeding season (Levins' diet breadth, B = 4.12) and is composed mainly of Orthoptera and Coleoptera, while during pre-migration, the species shows a more narrow diet breadth (B = 1.98) and feeds more often and on larger amounts of Orthoptera. These results indicate a specialised feeding strategy during pre-migration. In addition, the examination of the Orthoptera consumption during this period indicates a peak in the abundance of grasshoppers (Acrididae) in the second half of August. We suggest that at this time birds exploit high elevation open grasslands around the roosting site where grasshopper abundance is high. Thus, such areas are of high conservation importance as Lesser Kestrels depend on this localised abundance of Orthoptera in order to fuel up before their trans-Saharan migration.
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