Rare earth activated yttrium aluminate phosphors with modulated luminescence.

Yttrium aluminate (Y3 A5 O12 ) was doped with different rare earth ions (i.e. Gd(3+) , Ce(3+) , Eu(3+) and/or Tb(3+) ) in order to obtain phosphors (YAG:RE) with general formula,Y3-x-a Gdx REa Al5 O12 (x = 0; 1.485; 2.97 and a = 0.03). The synthesis of the phosphor samples was done using the simultaneous addition of reagents technique. This study reveals new aspects regarding the influence of different activator ions on the morpho-structural and luminescent characteristics of garnet type phosphor. All YAG:RE phosphors are well crystallized powders containing a cubic-Y3 Al5 O12 phase as major component along with monoclinic-Y4 Al2 O9 and orthorhombic-YAlO3 phases as the impurity. The crystallites dimensions of YAG:RE phosphors vary between 38 nm and 88 nm, while the unit cell slowly increase as the ionic radius of the activator increases. Under UV excitation, YAG:Ce exhibits yellow emission due to electron transition in Ce(3+) from the 5d level to the ground state levels ((2) F5/2 , (2) F7/2 ). The emission intensity of Ce(3+) is enhanced in the presence of the Tb(3+) ions and is decreased in the presence of Eu(3+) ions due to some radiative or non-radiative processes that take place between activator ions. By varying the rare earth ions, the emission colour can be modulated from green to white and red. Copyright © 2015 John Wiley & Sons, Ltd.

New TiO2/MgAl-LDH nanocomposites for the photocatalytic degradation of dyes.

In this study we report the synthesis of a series of composite nanostructures comprising LDH and TiO2 phases. The materials characterization showed that the LDH crystallites are encapsulated inside the TiO2 matrix after the anatase seeds are deposited on MgxAl-LDHs. The structure in which LDH phase is embedded into anatase matrix is unique bringing important advantages to the photocatalytic performances of the nanocomposites. The photocatalytic activity of the prepared nanocomposites was tested on the degradation of the methylene blue (MB) in aqueous solution. The photocatalytic activities of the nanocomposites were compared with commercial TiO2 nanoparticles Degussa P25. The nanocomposites exhibited superior photocatalytic activity in basic environment because the negatively charged surface of TiO2 nanoparticles at high pH attracts the positively charged methylene blue species.

Estrogen receptor alpha polymorphisms: correlation with clinicopathological parameters in breast cancer.

Polymorphisms in estrogen receptor alpha gene (ESR1) have been previously associated with breast cancer risk; however, the results were not fully consistent. Our purpose was to study interactions between common genotypes in ESR1, breast cancer risk and tumor phenotypes. 6 ESR1 single nucleotide polymorphisms (SNPs) were genotyped in 103 breast cancer patients and 90 controls using hybridization probes; the genotypes were correlated with known prognostic factors for breast cancer and 5 years-follow up data. To assess estrogen and progesterone receptors (ER, PR) and HER2/neu expressions, immunohistochemistry was performed. Our results showed that rs3798577 was significantly associated with the risk of breast cancer, the common allele C conferring susceptibility (p-trend=4 x 10(-5)); rs3798577 was also correlated with PR expression (p=0.01), but not with ER expression; rs2228480 (p=0.047) and rs1801132 (p=0.02) were associated with the age at diagnosis; rs1801132 was correlated with hypercholesterolemia (p=0.003) and increased BMI (body mass index) (p=0.01); rs2234693 showed a low significant association (p=0.042) with the tumor grade; rs3798577 was correlated with disease-free survival (p=0.05), allele C conferring increased risk for relapses, but it reached not statistical significance after adjustments. In conclusions, we identified four genotypes significantly correlated with either the risk or some tumor characteristics, suggesting that the main selection criteria of the investigated SNPs (frequency and the position in modulating domains of the gene) are pertinent instruments for establish correlations between the gene structure and the tumor phenotype.

[Risk factors involved in multiresistant infections with strains of Enterobacteriaceae]. / Factorii de risc implicati în infectiile cu tulpini de Enterobacteriaceae multirezistente.

OBJECTIVE: The present study aims to analyse the risk factors involvement in the cross infectious pathology determined by multiresistant Enterobacteriaceae, in hospitalised patients in the Intensive Care Unit at the County Emergency Clinical Hospital in Timisoara. MATERIAL AND METHOD: We carried out a case-control study with 3 groups of adult inpatients--200 patients with no superadded infectious pathology, 100 patients infected with Enterobacteriaceae strains resistant to 3 classes of antibacterial chemotherapeutic agents and 100 infected with multiresistant strains. Identification of bacterial germs was performed using API ID 20 E manual galleries (BioMérieux) and the inclusion in the resistance phenotypes was done using the Osiris Evolution (BioRad) analyser. RESULTS: Subjects infected with multiresistant strains are mostly male, (p=0.020, OR=1.8 [1.06-3.07], RR=1.49, [1.05-2.11]), with the mean age younger than that of the control group (p=0.011). The mean Charlson Comorbidity Index was 3.34 in Group III and 4.06 in Group I (p=0.027). The logistic regression application keeps as well as independent risk factors for multiresistance--the mechanical ventilation, consciousness impairment, prolonged hospitalization and the higher number of days of antibiotherapy. CONCLUSIONS: In this study, the nosocomial factors and basic pathology prevail to the detriment of other intrinsic risk factors.

Controlled drug delivery system based on ordered mesoporous silica matrices of captopril as angiotensin-converting enzyme inhibitor drug.

In the present study, captopril-loaded ordered mesoporous SBA-15 silica matrix were produced, functionalized, and characterized to obtain an efficient formulation of controlled drug delivery system. First, the starting SBA-15 materials are examined to verify that their synthesis has been successful considering the structural properties, using XRD, FTIR, and BET methods. Second, the influence of processing parameters of ordered mesoporous matrices for the loading and release of captopril was investigated. The release of captopril was controlled by tailoring the surface properties of the mesoporous silica via functionalization. The loading and release kinetics (in vitro in simulated gastric and intestinal fluids) showed that both of them were affected by the surface properties of the mesoporous silica materials. Such a formulation shows potential as an efficient controlled drug delivery system.

New SnO2/MgAl-layered double hydroxide composites as photocatalysts for cationic dyes bleaching.

A new type of nanocomposite containing SnO(2) has been obtained by wet impregnation of dehydrated Mg/Al-hydrotalcite-type compounds with ethanolic solutions of SnCl(4).2H(2)O. Tin chloride hydrolysis was achieved using NaOH or NH(4)OH aqueous solutions, at pH around 9, followed by the conversion into corresponding hydroxides through calcinations. The powder X-ray diffraction (PXRD) and UV-Vis diffuse reflectance (UV-DR) methods confirmed the structure of as-synthesized solids. The chemical composition and morphology of the synthesized materials were investigated by energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The as-synthesized materials were used for photocatalytic studies showing a good activity for methylene blue decolourization, which varies with SnO(2) content and used as a hydrolysing agent. The proposed mechanism is based on the shifting of flat band potential of SnO(2) due to the interaction with Mg/Al-LDH, this being energetically favourable to the formation of hydroxyl radicals responsible for methylene blue degradation.

Energy efficient on-sensor processing in Body Sensor Networks.

Body Sensor Networks (BSNs) have tremendous potential in facilitating the real-time monitoring of the health of an individual in their own environment. However to truly exploit this potential, the powerful signal processing and analysis techniques available in the hospital environment must also be deployed in BSNs. In this paper, techniques in algorithm development, communications, hardware architecture and circuit design are described that will achieve the necessary power savings to make intelligent BSNs a reality.

Synthesis and characterization of TiO2-pillared Romanian clay and their application for azoic dyes photodegradation.

The synthesis and properties of metal oxide pillared cationic clays (PILCs) has been subject to numerous studies in the last decades. In order to obtain TiO(2)-pillared type materials, sodium montmorillonite from Romania-areal of Valea Chioarului, having the following composition (% wt): SiO(2)-72.87; Al(2)O(3)-14.5; MgO-2.15; Fe(2)O(3)-1.13; Na(2)O-0.60; K(2)O-0.60; CaO-0.90; PC-5.70 and cation exchange capacity, determined by ammonium acetate method, of 82 meq/100g, as matrix, was used. Sodium form of the clay was modified, primarily, by intercalation of cetyl-trimethylammonium cations between negatively charged layers which will lead to the expansion of the interlayer space. For the preparation of the TiO(2)-pillared clay, the alkoxide molecules, as titania precursor, were adsorbed onto/into clay samples (1 mmol Ti/g clay), in hydrochloric acid environment, the resulted species being converted into TiO(2) pillars by calcination. The as-prepared materials have been used as catalysts for Congo Red dye photodegradation, under UV. The photocatalytic activity of the pillared clays is a function of TiO(2) pillars size, their increase leading to the enhancement of the contact areas between dye solution and photoactive species present in the interlayer space. The structural characteristics and properties of the obtained materials were investigated by X-ray Diffraction, Thermogravimetry Analysis, UV-vis Diffuse Reflectance, Transmission Electron Microscopy and Energy Dispersive X-ray Analysis.