Search results for " Plastic"

Hyperbranched Polyglycerol-Based Lipids via Oxyanionic Polymerization: Toward Multifunctional Stealth Liposomes

2010

We describe the synthesis of linear-hyperbranched lipids for liposome preparation based on linear poly(ethylene glycol) (PEG) and hyperbranched polyglycerol (PG). Molecular weights were adjusted to values around 3000 g/mol with varying degrees of polymerization of the linear and the branched segments in analogy to PEG-based stealth lipids; polydispersities were generally low and below 1.3. The hydrophobic anchors were introduced into the lipid structures as initiators for the anionic polymerization of ethylene oxide and are either based on cholesterol or on different aliphatic glyceryl ethers. Complete incorporation of the apolar initiators was evidenced by MALDI-ToF analysis at all stages …

Polyaspartylhydrazide Copolymer-Based Supramolecular Vesicular Aggregates as Delivery Devices for Anticancer Drugs

2008

In this paper we report on three different hydrophilic copolymers based on alpha,beta-polyaspartylhydrazide (PAHy) bearing butyric groups in the side chain (C 4) (PAHy-C 4) or a combination of butyric groups and positive charged residues ((carboxypropyl)trimethylammonium chloride, CPTACl) (PAHy-C 4-CPTA) that were synthesized and used for the preparation of new supramolecular vesicular aggregates (SVAs) containing gemcitabine as an antitumor drug. Gemcitabine-loaded SVAs containing synthesized PAHy derivatives were characterized from the physicochemical and technological point of view and the in vitro toxicity and anticancer activity on two different human cancer cell lines, i.e., CaCo-2 (h…

The influence of Sb doping on the local structure and disorder in thermoelectric ZnO:Sb thin films

2023

The experiment at HASYLAB/DESY was performed within the project I-20200161 EC. The research leading to this result has been supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01–2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2. This work was carried out in part through the use of the INL Advanced Electron Microscopy, Imaging and Spectroscopy Facility. This work (proposal ID 2018–020-022469) was car…

Delivery of liquorice extract by liposomes and hyalurosomes to protect the skin against oxidative stress injuries.

2015

Liquorice extract, obtained by percolation in ethanol of Glycyrrhiza glabra L. roots, was incorporated in liposomes and hyalurosomes, new phospholipid-sodium hyaluronate vesicles, and their protective effect against oxidative stress skin damages was probed. As a comparison, raw glycyrrhizin was also tested. All the vesicles were small in size (≤ 100 nm), with a highly negative zeta potential ensuring long-term stability, and able to incorporate a high amount of the extract. In vitro tests showed that the liquorice extract loaded in vesicles was able to scavenge DPPH free radical (80% inhibition) and to protect 3T3 fibroblasts against H2O2-induced oxidative stress, restoring the normal condi…

Impact of molecular weight on the formation of electrosprayed chitosan microcapsules as delivery vehicles for bioactive compounds.

2016

The molecular weight of chitosan is one of its most determinant characteristics, which affects its processability and its performance as a biomaterial. However, information about the effect of this parameter on the formation of electrosprayed chitosan microcapsules is scarce. In this work, the impact of chitosan molecular weight on its electrosprayability was studied and correlated with its effect on the viscosity, surface tension and electrical conductivity of solutions. A Discriminant Function Analysis revealed that the morphology of the electrosprayed chitosan materials could be correctly predicted using these three parameters for almost 85% of the samples. The suitability of using elect…

Supramolecular Antioxidant Assemblies of Hyperbranched Polyglycerols and Phenols

2014

Natural Compounds as Sustainable Additives for Biopolymers

2020

In the last few decades, the interest towards natural compounds, coming from a natural source and biodegradable, for biopolymers is always increasing because of a public request for the formulation of safe, eco-friendly, and sustainable materials. The main classes of natural compounds for biopolymers are: (i) naturally occurring fillers (nFil), such as nano-/micro- sized layered alumino-silicate: halloysite, bentonite, montmorillonite, hydroxyapatite, calcium carbonate, etc.; (ii) naturally occurring fibers (nFib), such as wood and vegetable fibers; (iii) naturally occurring antioxidant molecules (nAO), such as phenols, polyphenols, vitamins, and carotenoids. However, in this short review, …

On parabolic hemivariational inequalities and applications

1999

Elastic plastic analysis iterative solution

1998

The step-by-step analysis of finite element elastic plastic structures subjected to an assigned (quasi-static) loading history, is considered; it identifies with the well-known sequence of linear complementarity problems. An iterative technique devoted to solve the relevant linear complementarity problem is presented. It is based on the recursive solution of a suitable linear complementarity problem, deduced from the relevant one and easier than it. The procedure convergency is proved. Some noticing particular cases are examined. The physical meaning of the procedure is shown to be a plastic relaxation. The suitable numerical ranges for some check parameter values, to be utilized in the app…

Geographical variation in wing polymorphism of the waterstrider Aquarius najas (Heteroptera, Gerridae)

1999

The waterstrider Aquarius najas is wingless in Northern Europe, while winged individuals occur frequently in Central and Southern Europe. To test if the latitudinal difference is genetically controlled, we collected mature individuals from 10 different populations and raised their offspring in ‘common garden’ laboratory conditions. Half of these populations were from southern and the other half from central Finland. Daylength and temperature do influence wing development among other species of waterstriders, and thus we maintained a similar short daylength and warm conditions for all populations. These conditions should be favourable for wing development in general. Among laboratory-bred in…