Phase Identification of La-Doped Hard Magnetic Barium Ferrite Using Artificial Neural Network

A model based on an artificial neural network (ANN) was designed for the simulation and estimation of 2 theta and intensity values obtained by X-Ray Diffraction (XRD) of pure and La-doped barium ferrite powders which have been synthesized in ammonium nitrate melt. Its performance is evaluated by the influences of different La content, sintering temperature, Fe/Ba ratio, and washed in HCl (or not washed in HCl) samples. The XRD patterns of samples estimated by the ANN agree well with the experimental values, indicating that the model is reliable and adequate.     

Photoinduced Electron Transfer Between Pyridine Coated Cadmium Selenide Quantum Dots and Single Sheet Graphene

Interest in graphene as a two‐dimensional quantum‐well material for energy applications and nanoelectronics has increased exponentially in the last few years. The recent advances in large‐area single‐sheet fabrication of pristine graphene have opened unexplored avenues for expanding from nano‐ to meso‐scale applications. The relatively low level of absorptivity and the short lifetimes of excitons of single‐sheet graphene suggest that it needs to be coupled with light sensitizers in order to explore its feasibility for photonic applications, such as solar‐energy conversion. Red‐emitting CdSe quantum dots are employed for photosensitizing single‐sheet graphene with areas of several square centimeters. Pyridine coating of the quantum dots not only enhances their adhesion to the graphene surface, but also provides good electronic coupling between the CdSe and the two‐dimensional carbon allotrope. Illumination of the quantum dots led to injection of n‐carrier in the graphene phase. Time‐resolved spectroscopy reveals three modes of photoinduced electron transfer between the quantum dots and the graphene occurring in the femtosecond and picosecond time‐domains. Transient absorption spectra provide evidence for photoinduced hole‐shift from the CdSe to the pyridine ligands, thereby polarizing the surface of the quantum dots. That is, photoinduced electrical polarization, which favors the simultaneous electron transfer from the CdSe to the graphene phase. These mechanistic insights into the photoinduced interfacial charge transfer have a promising potential to serve as guidelines for the design and development of composites of graphene and inorganic nanomaterials for solar‐energy conversion applications.     

Long‐term oropharyngeal colonization by C. albicans in children with cystic fibrosis

This longitudinal prospective study aimed to determine the prevalence of oropharyngeal colonization by C. albicans in children with cystic fibrosis (CF), and observe the continuity of candidal colonization and the changes in production of virulence factors, susceptibility to antifungal agents and RAPD patterns of the isolates. Thirty‐seven children with CF were followed‐up for oropharyngeal C. albicans colonization for 18 months. The colonization rate was detected in 54%. All isolates were susceptible to amphotericin B, but those isolated from one patient were resistant to fluconazole. Biofilm production, secretory acid proteinase, phospholipase and esterase activity rates were 30%, 60%, 75% and 80%, respectively. RAPD analysis with the primers OPE‐03 and OPE‐18 was performed for genotyping. RAPD patterns of the strains isolated from the same patient were related to each other, whereas they were not related with other strains isolated from different patients. Two C. albicans strains isolated from the same patient were found to be unrelated to one another. As a result, long‐lasting colonization of the oropharyngeal mucosa of children with CF by endogenous C. albicans isolates having the same RAPD pattern was demonstrated. Colonization prevalance and development of resistance to antifungal agents and the increased production of virulence factors were not correlated. Copyright © 2013 John Wiley & Sons, Ltd.     

Total Antioxidant Activity and Total Phenolic Contents in Different Turkish Eggplant (Solanum Melongena L.) Cultivars

In this study, total water soluble antioxidant activity and phenolic content of 26 eggplant ( Solanum melongena L. ) cultivars were investigated. Total water soluble antioxidant activity of the cultivars varied from 2664 to 8247 μmolTrolox/kg, which is a 3.1-fold difference. Cultivars also showed significant variation for total phenolic contents ranging from 615 to 1376 mg/kg, a 2.2-fold difference. The two traits were significantly correlated and results of this study suggested that breeders can use the information to develop eggplant cultivars with high antioxidant activity.     

An integrated maritime surveillance system based on high-frequencysurface-wave radars. 2. Operational status and system performance

For pt.1 see ibid., vol.43, no.4, p.28-43 (2001). An integrated maritime surveillance (IMS) system, based on high-frequency surface wave radars (HFSWR), for monitoring surface and low-level air activity within the 200 nautical mile (nm) Exclusive Economic Zone (EEZ) is described in this two-part paper. The science behind the long-range performance of HFSWR was presented in Part 1(Sevgi et al. 2001). The system described was installed on Canada's east coast, where it is being used to demonstrate continuous, all-weather surveillance of the EEZ to beyond 200 nm. The system consists of two land-based HFSWRs and an operations control center (OCC). The two unmanned radars provide coverage of the Grand Banks region of Newfoundland, renowned for its offshore resources, particularly fish and oil. The system has been designed to assist authorities to more efficiently monitor such illegal activities as drug trafficking, smuggling, piracy, illicit fishing and illegal immigration. In addition, the system may be used for tracking icebergs, environmental protection, search and rescue, resource protection, sovereignty monitoring, and remote sensing of ocean surface currents and winds. Extensive performance testing of the system has been conducted using the two fully functional radars. It is shown that the HFSWR system complements existing surveillance assets to dramatically increase the effectiveness of air and surface reconnaissance missions by vectoring them directly to targets of interest     

Research of both γ-irradiation and La2O3 addition on structural and magnetoresistivity of Bi-2223 bulk superconductors

In this study, we investigate the effects of both gamma irradiation and the addition of lanthanum oxide (La₂O₃) on the Bi_1.85Pb_0.35Sr₂Ca₂Cu₃O_y (Bi-2223) bulk superconductors. Pure and lanthanum-added samples prepared by the solid-state reaction method were analyzed before and after gamma irradiation using various methods such as X-ray powder diffraction (XRD), the temperature dependence of resistivity under magnetic field (ρ-T). Bi-2223 + x La₂O₃ samples with x = 0.0, 1.0 and 5.0 wt% were fabricated. The synthesized samples were then subjected to gamma irradiation at different intensities, and the effects of radiation on the structural, electrical, and magnetic properties of the materials were examined. For this purpose, Bi-2223 superconductors in the form of discs were produced and cut into two pieces. One piece was exposed to gamma radiation under high vacuum conditions. The phase analyzes of the materials were carried out by XRD. Then, electrical analysis of the materials was made by measuring resistance under a magnetic field.     

Complications of 1303 central venous cannulations

Central venous catheterization (CVC), now a common procedure, has several major complications. We assessed their incidence in a prospective study of 1303 cannulations done in the intensive care unit or operating theatre. Chest radiographs were obtained to verify proper catheter placement and to detect pneumothorax. Complications were arterial puncture in 68 (5.2%) patients, arrhythmias in 21 (1.6%), cardiopulmonary arrest in 1 (0.1%), and pneumothorax in 5 (0.5%). The tip of the CVC was incorrectly located in 149 (11.2%). The chest radiograph was a valuable method for detecting complications of central venous catheterization.     

Predictors of left atrial thrombus and spontaneous echo contrast in rheumatic valve disease before and after mitral valve replacement

In this study we aimed to analyze, with reference to mitral regurgitation (MR), the incidence and predictors of left atrial (LA) thrombus and spontaneous echo contrast in patients with rheumatic valve disease before and after mitral valve replacement. The incidence of LA thrombus is known to be less in patients with MR. The impact of mitral valve replacement on this beneficial effect has not been studied in detail. The study included 169 consecutive patients (59 men and 110 women, average age 40 +/- 13 years) with rheumatic mitral valve disease who underwent transesophageal echocardiographic examination 1 to 3 days before and within 7 days (mean 4.0 +/- 1.3) after mitral valve replacement using mechanical prostheses in a single institution. The preoperative incidence of echocardiographic LA spontaneous echo contrast (SEC) was 1.1%, 30%, and 54%, and the incidence of thrombus was 1.1%, 13%, and 17% in the groups with MR, combined mitral stenosis + MR, and isolated mitral stenosis, respectively. In the MR group, SEC and thrombus incidence increased significantly after surgery. The independent predictors for postoperative thrombus development were atrial fibrillation, postoperative SEC, and preoperative thrombus. Thrombus recurred after surgery in 64% of 14 patients who had surgical thrombectomy. The presence of postoperative MR was associated with decreased risk of postoperative SEC and thrombus development. The interaction between MR and SEC and thrombus both before and after surgery provides further support for the protective effect of MR against LA thrombus formation.     

Poly(2‐hydroxyethyl methacrylate)/boric acid composite hydrogel as soft contact lens material: Thermal,optical, rheological,and enhanced antibacterial properties

The present work proposes to fabricate a composite hydrogel material that well characterized, transparent, biocompatible, and self‐antibacterial as potential soft contact lens material. For this purpose, poly(2‐hydroxyethyl methacrylate) (PHEMA)/boric acid (BA) composite hydrogels were successfully prepared by chemical crosslinking with BA through in situ polymerization using different BA ratios between 1 and 10% w/w. Afterward, the compositions, thermal stability, transparence, oxygen permeability, water uptake capacity, swelling ratio as well as morphological and rheological properties, in vitro degradability, in vitro cytotoxicity, and antibacterial properties of the all prepared materials were analyzed using a series of different techniques. The thermal stability, hydrophilicity, water uptake, oxygen permeability gradually increased depending ratio of BA, which is desirable for biomaterial. While the transparence and refractive index decreased, the composite hydrogels, except for BA content of 10 wt %, maintained enough transparency to be used for contact lens. In addition, PHEMA/BA composite hydrogels exhibited good cytocompatibility (PHEMA‐1%BA and PHEMA‐3%BA) and excellent antibacterial activity against Gram‐positive (Staphylococcus aureus and Enterococcus faecium) and Gram‐negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. Overall, the results demonstrated that the obtained PHEMA/BA composite hydrogels could be considered as self‐antibacterial contact lens and a potential composite biomaterial for other applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46575.