Drug–Polymer Interactions in Hydrogel‐based Drug‐Delivery Systems: An Experimental and Theoretical Study

In drug‐delivery systems, drug transport is a key step, but the interpretation of the transport mechanism is still controversial. Here, we investigated a promising hydrogel library loaded with the anticonvulsant drug ethosuximide (ESM). The self‐diffusion coefficient of ESM was measured using two methods: a direct and advanced measurement with a pulsed field gradient spin‐echo (PFGSE) method, using an NMR spectrometer equipped with high‐resolution magic angle spinning (HR‐MAS) probe, and an indirect one based on fitting in vitro drug‐delivery data. Starting from the experimental data a mathematical model without fitted parameters was developed and all the phenomena involved, that is, adsorption and diffusion, were considered. At low drug concentrations, adsorption prevails and consequently the diffusivity in the gels is lower than that in water. At high drug concentrations, where all adsorption sites are saturated, the diffusion in the gels is similar to that in a water solution. This study may pave the way for better device design.     

Green Deep Eutectic Solvents for Microwave-Assisted Biomass Delignification and Valorisation

Aiming to fulfil the sustainability criteria of future biorefineries, a novel biomass pretreatment combining natural deep eutectic solvents (NaDESs) and microwave (MW) technology was developed. Results showed that NaDESs have a high potential as green solvents for lignin fractionation/recovery and sugar release in the following enzymatic hydrolysis. A new class of lignin derived NaDESs (LigDESs) was also investigated, showing promising effects in wheat straw delignification. MW irradiation enabled a fast pretreatment under mild condition (120 °C, 30 min). To better understand the interaction of MW with these green solvents, the dielectric properties of NaDESs were investigated. Furthermore, a NaDES using the lignin recovered from biomass pretreatment as hydrogen bond donor was prepared, thus paving the way for a “closed-loop” biorefinery process.     

Anti-Multiple Myeloma Potential of Secondary Metabolites from Hibiscus sabdariffa—Part 2

Multiple Myeloma (MM) is an aggressive tumor causing millions of deaths every year and currently available therapies are often unsuccessful or correlated with severe side effects. In our previous work we demonstrated that the Hibiscus sabdariffa hydroalcoholic extract inhibits the growth of the MM cell line and we isolated two metabolites responsible for the activity: Hib-ester and Hib-carbaldehyde. Herein we report their interaction with proteasome, one of the main targets in the fight against MM. The molecular modelling study outlined a good interaction of both compounds with the target and these results prompted us to investigate their potential to inhibit proteasome. Metabolites were then isolated from the calyces and an extract with a high content of Hib-ester and Hib-carbaldehyde was prepared. An anticancer profile was drawn, evaluating apoptosis, autophagy and proteasome inhibition, with the anticancer properties being mainly attributed to the Hib-ester and Hib-carbaldehyde, while the proteasome inhibition of the extract could also be ascribed to the presence of anthocyanins, a class of secondary metabolites already known for their proteasome inhibitory activity.     

One-way multiparty communication lower bound for pointer jumping with applications

In this paper we study the one-way multiparty communication model, in which every party speaks exactly once in its turn. For every k, we prove a tight lower bound of Ω(n ^1/(k?1)}) on the probabilistic communication complexity of pointer jumping in a k-layered tree, where the pointers of the i-th layer reside on the forehead of the i-th party to speak. The lower bound remains nontrivial even for k = (logn)^1/2?? parties, for any constant ? > 0. Previous to our work a lower bound was known only for k =3 (Wigderson, see [7]), and in restricted models for k>3 [2},24,18,4,13]. Our results have the following consequences to other models and problems, extending previous work in several directions. The one-way model is strong enough to capture general (not one-way) multiparty protocols with a bounded number of rounds. Thus we generalize two problem areas previously studied in the 2-party model (cf. [30,21,29]). The first is a rounds hierarchy: we give an exponential separation between the power of r and 2r rounds in general probabilistic k-party protocols, for any k and r. The second is the relative power of determinism and nondeterminism: we prove an exponential separation between nondeterministic and deterministic communication complexity for general k-party protocols with r rounds, for any k,r. The pointer jumping function is weak enough to be a special case of the well-studied disjointness function. Thus we obtain a lower bound of Ω(n ^1/(k?1)) on the probabilistic complexity of k-set disjointness in the one-way model, which was known only for k = 3 parties. Our result also extends a similar lower bound for the weaker simultaneous model, in which parties simultaneously send one message to a referee [12]. Finally, we infer an exponential separation between the power of any two different orders in which parties send messages in the one-way model, for every k. Previous results [29, 7] separated orders based on who speaks first. Our lower bound technique, which handles functions of high discrepancy over cylinder intersections, provides a “party-elimination” induction, based on a restricted form of a direct-product result, specific to the pointer jumping function.     

Graphene transistors via in situ voltage-induced reduction of graphene-oxide under ambient conditions

Here, we describe a simple approach to fabricate graphene-based field-effect-transistors (FETs), starting from aqueous solutions of graphene-oxide (GO), processed entirely under ambient conditions. The process relies on the site-selective reduction of GO sheets deposited in between or on the surface of micro/nanoelectrodes. The same electrodes are first used for voltage-induced electrochemical GO reduction, and then as the source and drain contacts of FETs, allowing for the straightforward production and characterization of ambipolar graphene devices. With the use of nanoelectrodes, we could reduce different selected areas belonging to one single sheet as well.     

Communication: Conformation state diagram of polypeptides: a chain length induced α-β transition

By using a generic coarse grained polypeptide model, we perform multicanonical molecular dynamics simulations for determining the equilibrium conformation state diagram of a single homopolypeptide chain as a function of the chain length and temperature. The state diagram highlights the thermal regimes of stability for various conformational patterns in polypeptides, including swollen, random and collapsed coils, globular structures, extended and bended α helices, and compact β bundles. Remarkably, at low temperatures we observe a sharp transition from extended α helix to compact β bundles as the chain length increases. This finding indicates that the chain length is one of the intrisic factors that can trigger α-β transformations in a broad class of polypeptides.     

Total phenolic content and antioxidant activity of Salvia spp. exudates

The total phenolic content and antioxidant activity of 6 Salvia spp. exudates were measured to find new potential sources of natural antioxidants. Total phenolic content was assessed by a modified Prussian blue method, and the antioxidant activity by two methods: 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging capacity assay and lipoxygenase inhibitory assay. The total phenolic content ranged between 1.3 microg/mg DW (S. fallax) and 74.0 microg/mg DW (S. cacaliaefolia). In the DPPH test, S. cacaliaefolia was more effective than BHT, while in the inhibition of lipid peroxidation all the extracts presented good antioxidant capacity.     

Polymer‐based Scaffold Designs For In Situ Vascular Tissue Engineering: Controlling Recruitment and Differentiation Behavior of Endothelial Colony Forming Cells

In situ vascular tissue engineering has been proposed as a promising approach to fulfill the need for small‐diameter blood vessel substitutes. The approach comprises the use of a cell‐free instructive scaffold to guide and control cell recruitment, differentiation, and tissue formation at the locus of implantation. Here we review the design parameters for such scaffolds, with special emphasis on differentiation of recruited ECFCs into the different lineages that constitute the vessel wall. Next to defining the target properties of the vessel, we concentrate on the target cell source, the ECFCs, and on the environmental control of the fate of these cells within the scaffold. The prospects of the approach are discussed in the light of current technical and biological hurdles.