Advancing PHBV Biomedical Potential with the Incorporation of Bacterial Biopigment Prodigiosin.

The quest for sustainable biomaterials with excellent biocompatibility and tailorable properties has put polyhydroxyalkanoates (PHAs) into the research spotlight. However, high production costs and the lack of bioactivity limit their market penetration. To address this, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was combined with a bacterial pigment with strong anticancer activity, prodigiosin (PG), to obtain functionally enhanced PHBV-based biomaterials. The samples were produced in the form of films 115.6-118.8 µm in thickness using the solvent casting method. The effects of PG incorporation on the physical properties (morphology, biopolymer crystallinity and thermal stability) and functionality of the obtained biomaterials were investigated. PG has acted as a nucleating agent, in turn affecting the degree of crystallinity, thermal stability and morphology of the films. All samples with PG had a more organized internal structure and higher melting and degradation temperatures. The calculated degree of crystallinity of the PHBV copolymer was 53%, while the PG1, PG3 and PG3 films had values of 64.0%, 63.9% and 69.2%, respectively. Cytotoxicity studies have shown the excellent anticancer activity of films against HCT116 (colon cancer) cells, thus advancing PHBV biomedical application potential.

Design of Pt-Sn-Zn Nanomaterials for Successful Methanol Electrooxidation Reaction.

This work highlights the potential for the synthesis of new PtSnZn catalysts with enhanced efficiency and durability for methanol oxidation reaction (MOR) in low-temperature fuel cells. In this research, PtZn and PtSnZn nanoparticles deposited on high surface area Vulcan XC-72R Carbon support were created by a microwave-assisted polyol method. The electrochemical performances of synthesized catalysts were analyzed by cyclic voltammetry and by the electrooxidation of adsorbed CO and the chronoamperometric method. The physicochemical properties of obtained catalysts were characterized by transmission electron microscopy (TEM), thermogravimetric (TGA) analysis, energy dispersive spectroscopy (EDS) and by X-ray diffraction (XRD). The obtained findings showed the successful synthesis of platinum-based catalysts. It was established that PtSnZn/C and PtZn/C catalysts have high electrocatalytic performance in methanol oxidation reactions. Catalysts stability tests were obtained by chronoamperometry. Stability tests also confirmed decreased poisoning and indicated improved stability and better tolerance to CO-like intermediate species. According to activity and stability measurements, the PtSnZn/C catalyst possesses the best electrochemical properties for the methanol oxidation reaction. The observed great electrocatalytic activity in the methanol oxidation reaction of synthesized catalysts can be attributed to the beneficial effects of microwave synthesis and the well-balanced addition of alloying metals in PtSnZn/C catalysts.

Synthesis of octenyl succinic anhydride-modified levan and investigation of its microstructural, physicochemical, and emulsifying properties.

In this study, levan from Bacillus licheniformis NS032 was modified in an aqueous medium by octenyl succinic anhydride (OSA), and the properties of the obtained derivatives were studied. The maximum efficiency in the synthesis reaction was achieved at 40 °C and a polysaccharide slurry concentration of 30 %. Increasing the reagent concentration (2-10 %) led to an increase in the degree of substitution (0.016-0.048). Structures of derivatives were confirmed by FTIR and NMR. Scanning electronic microscopy, thermogravimetry, and dynamic light scattering analyses showed that the derivatives with degrees of substitution of 0.025 and 0.036 retained levan's porous structure and thermostability and showed better colloidal stability than the native polysaccharide. The intrinsic viscosity of derivatives increased upon modification, while the surface tension of the 1 % solution was lowered to 61 mN/m. Oil-in-water emulsions prepared with sunflower oil (10 % and 20 %) by mechanical homogenization and 2 and 10 % derivatives in the continuous phase showed mean oil droplet sizes of 106-195 µm, while the distribution curves exhibited bimodal character. The studied derivatives have a good capacity to stabilize emulsions, as they have a creaming index ranging from 73 % to 94 %. The OSA-modified levans could have potential applications in new formulations of emulsion-based systems.

Bacterial nanocellulose as green support of platinum nanoparticles for effective methanol oxidation.

Bacterial nanocellulose, BNC, has emerged as a new class of nanomaterials recognized as renewable, biodegradable, biocompatible and material for versatile applications. BNC also proved as a perfect support matrix for metallic nanoparticle synthesis and appeared as suitable alternative for widely used carbon based materials. Following the idea to replace commonly used carbon based materials for platinum supports with the green and sustainable one, BNC appeared as an excellent candidate. Herein, microwave assisted synthesis has been reported for the first time for platinum nanoparticles supported on BNC as green material. Bacterial nanocelullose-platinum catalyst, Pt/BNC, was investigated by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), atomic force microscopy (AFM), X-ray diffractometry (XRD) and transmission-electron microscopy (TEM) analysis. The obtained results confirmed successful synthesis of new Pt-based catalyst. It was found that Pt/BNC catalyst has high electrocatalytic performance in methanol oxidation reaction. Green/sustainable catalytic system is highly desirable and provided by the elegant microwave assisted synthesis of Pt/BNC will pave the way for a larger scale application and expedite the market penetration of such fuel cells.

Bibliometric trend and patent analysis in nano-alloys research for period 2000-2013.

This paper presents an overview of current situation in nano-alloys investigations based on bibliometric and patent analysis. Bibliometric analysis data, for the period 2000 to 2013, were obtained using Scopus database as selected index database, whereas analyzed parameters were: number of scientific papers per year, authors, countries, affiliations, subject areas and document types. Analysis of nano-alloys patents was done with specific database, using the International Patent Classification and Patent Scope for the period 2003 to 2013. Information found in this database was the number of patents, patent classification by country, patent applicators, main inventors and publication date.

Bibliometric trend and patent analysis in nano-alloys research for period 2000-2013.

This paper presents an overview of current situation in nano-alloys investigations based on bibliometric and patent analysis. Bibliometric analysis data, for period from 2000 to September 2013, were obtained using Scopus database as selected index database, whereas analyzed parameters were: number of scientific papers per years, authors, countries, affiliations, subject areas and document types. Analysis of nano-alloys patents was done with specific database, using the International Patent Classification and Patent Scope for the period from 2003 to 2013 year. Information found in this database was the number of patents, patent classification by country, patent applicators, main inventors and pub date.

Characterization of PCBs from computers and mobile phones, and the proposal of newly developed materials for substitution of gold, lead and arsenic.

In this paper, we have analyzed parts of printed circuit board (PCB) and liquid crystal display (LCD) screens of mobile phones and computers, quantitative and qualitative chemical compositions of individual components, and complete PCBs were determined. Differential thermal analysis (DTA) and differential scanning calorimetry (DSC) methods were used to determine the temperatures of phase transformations, whereas qualitative and quantitative compositions of the samples were determined by X-ray fluorescence spectrometry (XRF), inductively coupled plasma optical emission spectrometry (ICP-OES), and scanning electron microscopy (SEM)-energy dispersive X-ray spectrometry (EDS) analyses. The microstructure of samples was studied by optical microscopy. Based on results of the analysis, a procedure for recycling PCBs is proposed. The emphasis was on the effects that can be achieved in the recycling process by extraction of some parts before the melting process. In addition, newly developed materials can be an adequate substitute for some of the dangerous and harmful materials, such as lead and arsenic are proposed, which is in accordance with the European Union (EU) Restriction of the use of certain hazardous substances (RoHS) directive as well as some alternative materials for use in the electronics industry instead of gold and gold alloys.