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关键词： hemostasis   thrombosis   rivaroxaban   pharmaceutical nanotechnology   polymeric nanoparticles  

摘要： Rivaroxaban (RXB), an oral direct factor Xa inhibitor, presents innovative therapeutic profile. However, RXB has shown adverse effects, mainly due to pharmacokinetic limitations, highlighting the importance of developing more effective formulations. Therefore, this work aims at the preparation, physicochemical characterization and in vitro evaluation of time-dependent anticoagulant activity and toxicology profile of RXB-loaded poly(lactic-co-glycolic acid) (PLGA)/ poloxamer nanoparticles (RXBNps). RXBNp were produced by nanoprecipitation method and physicochemical characteristics were evaluated. In vitro analysis of time-dependent anticoagulant activity was performed by prothrombin time test and toxicological profile was assessed by hemolysis and MTT reduction assays. The developed RXBNp present spherical morphology with average diameter of 205.5 +/- 16.95 nm (PdI 0.096 +/- 0.04), negative zeta potential (-26.28 +/- 0.77 mV), entrapment efficiency of 91.35 +/- 2.40%, yield of 41.81 +/- 1.68% and 3.72 +/- 0.07% of drug loading. Drug release was characterized by an initial fast release followed by a sustained release with 28.34 +/- 2.82% of RXB available in 72 h. RXBNp showed an expressive time-dependent anticoagulant activity in human and rat blood plasma and non-toxic profile. Based on the results presented, it is possible to consider that RXBNp may be able to assist in the development of promising new therapies for treatment of thrombotic disorders.

关键词： Polymer composite   Proton exchange membrane   Polybenzimidazole   Graphene oxide   HT-PEMFC  

摘要： Polymer composite membranes are fabricated using poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (PBI) as a polymer matrix and imidazole functionalized graphene oxide (ImGO) as a filler material for high temperature proton exchange membrane fuel cell applications. ImGO is prepared by the reaction of o-phenylenediamine with graphene oxide (GO). The compatibility of ImGO with PBI matrix is found to be better than that of GO, and as a result PBI composite membrane having ImGO exhibits improved physicochemical properties and larger proton conductivity compared with pure PBI and PBI composite membrane having GO. For example, PBI composite membrane having 0.5 wt% of ImGO shows enhanced tensile strength (219.2 MPa) with minimal decrease of elongation at break value (28.8%) compared with PBI composite membrane having 0.5 wt% of GO (215.5 MPa, 15.4%) and pure PBI membrane without any filler (181.0 MPa, 34.8%). The proton conductivity of this membrane, at 150 degrees C under anhydrous condition, is 77.52 mS cm(-1). (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

关键词： Haze-to-dust transition   Physicochemical properties   Individual particles analysis   Aerosol mass spectrometer   Secondary formation  

摘要： The variations in physicochemical properties of airborne particles collected during a typical transition from haze to dust were investigated using single particle analysis with transmission and scanning electron microscopes combined with online measurement of chemical compositions of airborne particles in Beijing in February 2013. The transition was divided into three phases based on the weather condition. During haze pollution (Phase 1), gaseous and particle pollutants enhanced gradually. Results from single particle analysis showed that more coatings and more anthropogenic elements (e.g., S) appeared on the surface of fine and coarse particles, which was probably caused by efficient aqueous-phase reactions under high humidity (70%) condition. Phase 2 was dust intrusion episode. PM10 reached over 1000 mu g m(-3). Larger fractions of mineral particles and bare-like soot particles were observed in fine particles, while the fraction of secondary particles with coatings decreased. The proportion of black carbon in submicron particles also increased. Photochemical oxidation in gas phase likely dominated in secondary formation under high O-3 concentration. After the dust episode (Phase 3), secondary formation enhanced obviously. Soot aged quickly and had a larger mode of 0.45 mu m than the other phases. The size modes of airborne fine particles during Phases 1 and 3 were 0.35 mu m, which were a bit larger than that during Phase 2 (0.24 mu m). These results indicate that dust plumes accompanied with strong wind brought mineral particles in both fine and coarse modes and freshly emitted particles with smaller sizes, and swept away pre-presence air pollutants. This study could provide detailed information on the physicochemical properties of airborne particles during typical severe pollution processes in a short time. Such short-term change should be taken into account in order to more accurately assess the environmental, climatic and health-related effects of airborne part

关键词： Peptides and proteins   Reaction products   Fluorescence   Cells   Conjugate acid-base pairs  

摘要： Most therapeutic agents used for treating brain malignancies face hindered transport through the blood-brain barrier (BBB) and poor tissue penetration. To overcome these problems, we developed peptide conjugates of conventional and experimental anticancer agents. SynB3 cell-penetrating peptide derivatives were applied that can cross the BBB. Tuftsin derivatives were used to target the neuropilin-1 transport system for selectivity and better tumor penetration. Moreover, SynB3-tuftsin tandem compounds were synthesized to combine the beneficial properties of these peptides. Most of the conjugates showed high and selective efficacy against glioblastoma cells. SynB3 and tandem derivatives demonstrated superior cellular internalization. The penetration profile of the conjugates was determined on a lipid monolayer and Transwell co-culture system with noncontact HUVEC-U87 monolayers as simple ex vivo and in vitro BBB models. Importantly, in 3D spheroids, daunomycin-peptide conjugates possessed a better tumor penetration ability than daunomycin. These conjugates are promising tools for the delivery systems with tunable features.

关键词： Vegetable fibers   Polypropylene fiber   Physical properties   Mechanical properties   High temperatures   Microstructure  

摘要： Sustainable development today requires smart deployment of renewable environmentally-friendly materials and innovative thoughts. It is unavoidable to assess their performance and engineering properties to be accepted by the civil engineering community. Thus, vegetable fibers as reinforcement for cementitious materials are a very interesting eco-option for the construction industry. This paper study the behavior of metakaolin cementitious mortars reinforced with vegetable (VF)/polypropylene (PP) fibers under high temperature exposure. Vegetable fibers were previously treated with calcium hydroxide in order to improve their paste-adhesion and durability. Four VF mortars (including Alfa mortar (MAF), Diss mortar (MDS), Date Palm mortar (MDP), Hemp mortar (MHE)), one PP mortar (MPP) and one control mortar (CM) were made. The mixes had a sand/binder ratio of 3, 30% matakaolin content, and 0.1%/m(3) fibers dosage. The induced firing-changes were studied at room temperature (20 degrees C) and after heating process at 150, 300, 450, and 600 degrees C. The tested properties were: residual mechanical strengths, ultrasonic velocity, thermal conductivity, porosity, density, thermogravemetric analysis, and optical and microstructural observations. The results showed a similar behavior of vegetable and polypropylene fibers' mortars under fire with a different mechanism;a diminished spalling with fibred mortars;Ca(OH)(2) treatment and metakaolin rich matrix was a good prescription to get enhanced VF-mortars properties. (C) 2021 Elsevier Ltd. All rights reserved.

关键词： Potato peel   Sour orange leaf   Lightweight brick   Sound insulation   Plant residue  

摘要： Using plant residues in building materials may reduce both short and long-term effects on the environment. In this paper, we used potato peel powder (PPP) to investigate the effects of this residue on sound insulation and other physicochemical properties. To achieve the optimal properties of the bricks, we utilized three percentages of dried PPP. We dried bricks and then fired them in the kiln at 1000 degrees C for four hours. Comparing the dried PPP and sour orange leaf (SOL) powder analysis, which was previously studied, showed that by using 7% of SOL powder, the compressive strength, apparent dry density, saturated density, and thermal conductivity decreased by 77%, 12.5%5, 4.4%, and 76.2%, respectively. While, porosity, water absorption, total shrinkage, dry shrinkage, soluble salt, and sound insulation are increased by 32.4%, 51.6%, 61.9%, 54.05%, 34.21%, and 13.68% compared to the ordinary clay bricks (CBs). However, in this study by adding 7% of dried PPP, the compressive strength, apparent dry density, saturated density, and thermal conductivity are decreased by 88%, 11.9%, 5.4%, 97.7%, and 81.6%, respectively. While porosity, water absorption, total shrinkage, dry shrinkage, soluble salt, and sound insulation are increased by 27%, 46%, 59.52%, 45.95%, 26.32%, and 18.62%, respectively, in comparison with the ordinary ones. Weight reduction in structures, sound insulation at natural frequencies, and crop residue management are the other advantages of these bricks compared to the ordinary clay ones. This value showed an 18.62% increase in bricks with 5% of PPP at a frequency of 5000 HZ compared to the ordinary bricks, which are higher than bricks with 3% and 7% of PPP. Also, these bricks are highly recommended in partition walls since the bricks used in these walls are usually ignored in strength and can be cost-effective due to the low cost of carrying products. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： PET-poly(terephtalate ethylene)   Fly ash   Composite lightweight aggregate   Portland cement   Circular economy   Eco-composite  

摘要： This article presents testings' results of cement composites with Composite Lightweight Aggregates (CLAs) as a partial substitute of natural aggregates. A new sustainable eco-composite manufacturing took place in laboratory conditions by using 100% waste by-products: PET flakes and sewage sludge fly ash (ssFA) streams or siliceous fly ash (FA). The manufactured (EN 196-1) modified cement mortars were tested in a various series of CLAs by applying volume replacements of 10% and 25% regarding the standard aggregate. The new insights on physical-chemical properties of the original materials and effective water and mechanical performance of both the fresh and hardened specimens contrasted the qualitative and quantitative assessments in the function of the two different aggregates production methods lines. Frattini test is also used to assess the impact of the aggregate composite on the cement composite and their mutual interactions. The obtained results show that the use of CLA as a substitute of standard aggregate allows reducing the water content in the mix while maintaining good workability and increasing compressive and flexural strengths up to 25% of reference mortar. (c) 2020 Elsevier Ltd. All rights reserved.

关键词： biopolymers and renewable polymers   degradation   electrospinning   films   spectroscopy  

摘要： The preparation by electrospraying of a bilayer film formed by a pectin layer (hydrophilic, polar) and a zein layer (hydrophobic, nonpolar), is a difficult task that has not yet been reported. Herein, the feasibility of producing films by electrostatic atomization was studied, as well as the changes in the superficial and physicochemical characteristics of the bilayer film. Results showed that it is possible to produce a flexible and yellow bilayer film (101.07 +/- 8.11 mu m) with a continuous surface structure and a well-defined interface, without chemical interactions between both layers nor antimicrobial activity. This study is one of the first to show that the electrospraying technique can be used to generate biodegradable bilayer films using hydrophilic/hydrophobic biopolymer solutions.