Disinfection of polymicrobial urines by electrochemical oxidation: Removal of antibiotic-resistant bacteria and genes.

In this work, data obtained from the University Hospital Complex of Albacete (Spain) were selected as a case study to carry out the disinfection experiments. To do this, different configurations of electrochemical reactors were tested for the disinfection of complex urines. Results showed that 4-6 logs bacterial removal were achieved for every bacterium tested when working with a microfluidic flow-through reactor after 180 min (0.423 Ah dm-3). The MIKROZON® cell reached a total disinfection after 60 min (1.212 Ah dm-3), causing severe damages induced in the cell walls observed in SEM images. The concentration profiles of the electrogenerated disinfectants in solution could explain the differences observed. Additionally, a mean decrease in the ARGs concentration ranked as follows: blaKPC (4.18-logs) > blaTEM (3.96-logs) > ermB (3.23-logs) using the MIKROZON® cell. This electro-ozonizer could be considered as a suitable alternative to reduce the risk of antibiotic resistance spread. Hence, this study provides an insight into different electrochemical reactors for the disinfection of complex hospital urine matrices and contributes to reduce the spread of antibiotic resistance through the elimination of ARGs. A topic of great importance nowadays that needs to be further studied.

Acetone-Sensitive Thin Films Comprising Coal Fly Ash Na-X Zeolites and Sol-Gel Nb2O5 Matrix.

In this study, thin composite films of a sol-gel Nb2O5 matrix doped with coal fly ash Na-X zeolites were deposited by the spin-coating method. Fly ash of lignite coal collected from the electrostatic precipitators of one of the biggest TPPs in Bulgaria was used as a raw material for obtaining zeolites. Zeolite Na-X was synthesized by ultrasonic-assisted double stage fusion-hydrothermal alkaline conversion of coal fly ash. In order to improve the optical quality and sensing properties of the deposited thin films, synthesized zeolites were wet-milled for 60, 120, and 540 s prior to film deposition. The surface morphology of zeolite powders was studied both by scanning electron microscopy and transmission electron microscopy, while their porosity was investigated by N2-physisorption. Refractive index, extinction coefficient, and thickness of the films were determined through fitting of their reflectance spectra. The sensing ability of thin films towards acetone vapors was tested by measuring the reflectance spectra prior to and during exposure to the analyte, and the change in the reflection coefficient ∆R of the films was calculated. The influence of milling time of zeolites on the sensing and optical properties of the films was assumed and confirmed.

Synthesis and Characterization of Macroinitiators Based on Polyorganophosphazenes for the Ring Opening Polymerization of N-Carboxyanhydrides.

Among the various biocompatible amphiphilic copolymers, biodegradable ones are the most promising for the preparation of drug delivery systems since they are destroyed under physiological conditions, that, as a rule, reduce toxicity and provide controlled release of the drug. Hybrid graft-copolymers consisting of the main inorganic polyphosphazene chain and polypeptide side chains are of considerable interest for the development of delivery systems with a controlled degradation rate, since the main and side chains will have different degradation mechanisms (chemical and enzymatic hydrolysis, respectively). Variable particle degradation rate, controlled by the adjusting the composition of substituents, will allow selective delivery in vivo and controlled drug release. The present work proposes the preparation of biodegradable macroinitiators based on polyorganophosphazenes for the synthesis of hybrid copolymers. Synthesis of novel biodegradable macroinitiators based on polyorganophosphazenes was performed via macromolecular substitution of a polydichlorophosphazene chain with the sodium alcoholates, amines and amino acids. The composition of copolymers obtained was calculated using NMR. These polyorganophosphazenes bearing primary amino groups can be considered as convenient macroinitiators for the polymerization of NCA of α-amino acids in order to prepare hybrid copolymers polyphosphazene-graft-polypeptide. The developed macroinitiators were amphiphilic and self-assembled in the aqueous media into nanoparticles. Furthermore, the ability to encapsulate and release a model substance was demonstrated. In addition, the in vitro cytotoxicity of synthesized polymers was evaluated using two cell lines.

Traditional games in elementary school: Relationships of student's personality traits, motivation and experience with learning outcomes.

This study promotes a novel teaching approach for integration of children's traditional games in elementary school program. It gives description of six traditional games and their educational prospects, implemented in six learning sessions in five elementary schools in Macedonia, involving 102 students. The comparison of learning achievements between these learning sessions and standard classes revealed increased students' learning performance on comparable topics. To understand the reason for improvement, we have surveyed students after each session and tested the gathered data set via the development of a structural equation model that examines the relationships between student's personality traits, motivation and experience with learning outcomes. The findings show that students' achievements were directly influenced by students' intrinsic and extrinsic motivational factors, as well as perceived experience. Additionally, the integration of traditional games in the elementary school classroom was equally accepted among all students, since their personality traits did not directly influence their experience or learning outcomes. Still, the link between the students' personality dimensions and motivation revealed that introvert children might have slightly increased motivation and possibility to open up during game-play in such collaborative environments.

Influence of Macromolecular Architecture on the Optical and Humidity-Sensing Properties of Poly(N,N-Dimethylacrylamide)-Based Block Copolymers.

The influence of the macromolecular architecture of block copolymers containing poly(N,N-dimethyl acrylamide) (PDMA) on the optical characteristics and sensing properties of corresponding thin films is discussed. Series of hydrophilic PDMA-based copolymers of different chemical composition and chain architecture such as triblock, star-shaped, and branched were synthesized. The copolymers were characterized using conventional spectroscopic techniques as well as methods for characterization of copolymer macromolecular characteristics in solution, namely size-exclusion chromatography and static light scattering. Thin films of the copolymers of nanometer scale thickness were deposited on silicon substrates by the spin-coating method. The refractive index and extinction coefficient of the copolymer films were calculated from the reflectance spectra by using non-linear curve fitting methods and the composition-structure-optical properties relationships were evaluated. Humidity-sensing properties of the films were studied by measuring reflectance spectra of the films at a relative humidity range from 5 to 95%RH. The implementation of the copolymer films as optical sensors of humidity is justified and discussed.

Vapor responsive one-dimensional photonic crystals from zeolite nanoparticles and metal oxide films for optical sensing.

The preparation of responsive multilayered structures with quarter-wave design based on layer-by-layer deposition of sol-gel derived Nb(2)O(5) films and spin-coated MEL type zeolite is demonstrated. The refractive indices (n) and thicknesses (d) of the layers are determined using non-linear curve fitting of the measured reflectance spectra. Besides, the surface and cross-sectional features of the multilayered structures are characterized by scanning electron microscopy (SEM). The quasi-omnidirectional photonic band for the multilayered structures is predicted theoretically, and confirmed experimentally by reflectance measurements at oblique incidence with polarized light. The sensing properties of the multilayered structures toward acetone are studied by measuring transmittance spectra prior and after vapor exposure. Furthermore, the potential of the one-dimensional photonic crystals based on the multilayered structure consisting of Nb(2)O(5) and MEL type zeolite as a chemical sensor with optical read-out is discussed.

Zeolite films as building blocks for antireflective coatings and vapor responsive Bragg stacks.

Zeolite films (LTL, BEA and MFI) are prepared with a thickness in the range 50-170 nm through a multistep spin-on deposition method. The optical properties of the zeolite films including refractive index, extinction coefficient and thickness are determined from the reflectance spectra using a nonlinear curve fitting method. The total free pore volume of the films using the Bruggeman effective medium theory is calculated. The potential of the zeolite films for broadband antireflection (AR) application is demonstrated. Five times reduction of the reflectance of a silicon substrate covered with the double AR films comprising of MFI type zeolite (120 nm) deposited on Nb2O5 (60 nm) is achieved. Additionally, the MFI zeolite film is used as a building block of vapor responsive Bragg stacks with a strong response towards acetone. The reversible response of the Bragg stacks towards acetone without additional annealing opens up the possibility of preparing sensors with optical read-out by incorporation of sensitive and transducer elements into a single device.