Reverse Microemulsion Synthesis, Structure, and Luminescence of Nanosized REPO(4):Ln(3+) (RE = La, Y, Gd, or Yb, and Ln = Eu, Tm, or Er)

A surfactant-mediated solution route for the obtainment of nanosized rare-earth orthophosphates of different compositions (LaPO(4):Eu(3+), (Y,Gd)PO(4):Eu(3+),LaPO(4):Tm(3+), YPO(4):Tm(3+), and YbPO(4):Er(3+)) is presented, and the implications of the morphology control on the solids properties are discussed. The solids are prepared in water-in-heptane microemulsions, using cetyltrimethylammonium bromide and 1-butanol as the surfactant and cosurfactant; the alteration of the starting microemulsion composition allows the obtainment of similar to 30 nm thick nanorods with variable length. The morphology and the structure of the solids were evaluated through scanning electron microscopy and through powder X-ray diffractometry; dynamic light scattering and thermal analyses were also performed. The obtained materials were also characterized through vibrational (FTIR) and luminescence spectroscopy (emission/excitation, luminescence lifetimes, chromaticity, and quantum efficiency), where the red, blue, and upconversion emissions of the prepared phosphors were evaluated.

Unraveling the Na,K-ATPase alpha(4) Subunit Assembling Induced by Large Amounts of C(12)E(8) by Means of Small-Angle X-ray Scattering

In the current work, we studied the effect of the nonionic detergent dodecyloctaethyleneglycol, C(12)E(8), on the structure and oligomeric form of the Na,K-ATPase membrane enzyme (sodium-potassium pump) in aqueous suspension, by means of small-angle X-ray scattering (SAXS). Samples composed of 2 mg/mL of Na,K-ATPase, extracted from rabbit kidney medulla, in the presence of a small amount of C(12)E(8) (0.005 mg/mL) and in larger concentrations ranging from 2.7 to 27 mg/mL did not present catalytic activity. Under this condition, an oligomerization of the alpha subunits is expected. SAXS data were analyzed by means of a global fitting procedure supposing that the scattering is due to two independent contributions: one coming from the enzyme and the other one from C(12)E(8) micelles. In the small detergent content (0.005 mg/mL), the SAXS results evidenced that Na,K-ATPase is associated into aggregates larger than (alpha beta)(2) form. When 2.7 mg/mL of C(12)E(8) is added, the data analysis revealed the presence of alpha(4) aggregates in the solution and some free micelles. Increasing the detergent amount up to 27 mg/mL does not disturb the alpha(4) aggregate: just more micelles of the same size and shape are proportionally formed in solution. We believe that our results shed light on a better understanding of how nonionic detergents induce subunit dissociation and reassembling to minimize the exposure of hydrophobic residues to the aqueous solvent.

Parametric analyses of anxiety in zebrafish scototaxis

Scototaxis, the preference for dark environments in detriment of bright ones, is an index of anxiety in zebrafish. In this work, we analyzed avoidance of the white compartment by analysis of the spatiotemporal pattern of exploratory behavior (time spent in the white compartment of the apparatus and shuttle frequency between compartments) and swimming ethogram (thigmotaxis, freezing and burst swimming in the white compartment) in four experiments. In Experiment 1, we demonstrate that spatiotemporal measures of white avoidance and locomotion do not habituate during a single 15-min session. In Experiments 2 and 3, we demonstrate that locomotor activity habituates to repeated exposures to the apparatus, regardless of whether inter-trial interval is 15-min or 24-h; however, no habituation of white avoidance was observed in either experiment. In Experiment 4, we confined animals for three 15-min sessions in the white compartment prior to recording spatiotemporal and ethogram measures in a standard preference test. After these forced exposures, white avoidance and locomotor activity showed no differences in relation to non-confined animals, but burst swimming, thigmotaxis and freezing in the white compartment were all decreased. These results suggest that neither avoidance of the white compartment nor approach to the black compartment account for the behavior of zebrafish in the scototaxis test. (C) 2010 Elsevier B.V. All rights reserved.

Synthesis, X-ray analysis and DFT study of 2-amino-3-(N-oxipiridin-4-ilsulfanil)-propionic acid dihydrate

The title compound, C(8)H(14)N(2)O(5)S 2(H(2)O), 2-amino-3-(N-oxipiridin-4-ilsulfanil)-propionic acid dihydrate, is obtained by the reaction of cysteine and 4-nitropyridine N-oxide in dimethylformamide, removing the NO(2) group from the benzene ring and releasing nitrous acid into the solution. The molecule exists as a Zwitterion. Hydrogen bond interactions involving the title molecule and water molecules allow the formation of R(5)(5)(23) edge fused rings parallel to (010). Water molecules are connected independently, forming infinite chains (wires), in square wave form, along the b-axis. The chirality of the cysteine molecule used in the synthesis is retained in the title molecule. A density functional theory (DFT) optimized structure at the B3LYP/6-311G(3df,2p) level allows comparison of calculated and experimental IR spectra.

Amphiphilic cerium(III) beta-diketonate as a catalyst for reducing diesel/biodiesel soot emissions

This work reports on the synthesis, characterization and applications of the new cerium(III) beta-diketonate Ce(hdacac)(3)(Hhdacac)(3)center dot 2H(2)O (where hdacac and Hhdacac denote, respectively, the hexadecylpentane-2,4-dionate and hexadecylpentane-2,4-dione ligands) as catalyst for the reduction of automotive emissions. Due to its amphiphilic character, this complex can be solubilized in non-polar fuels, thus generating cerium(IV) oxide particles, which efficiently catalyze the oxidation of diesel/biodiesel soot. The synthesized complex was characterized by microanalysis (C, H), thermal analysis, and infrared spectroscopy. Scanning electron microscopy, X-ray diffractometry, and specific surface area measurements attested that the complex can act as a soluble precursor of homogeneous CeO(2) spherical nanoparticles. The efficiency of this compound as catalyst for the reduction of soot emission was evaluated through static studies (comprising carbon black oxidation), which confirmed that increasing concentrations of the complex result in lower carbon black oxidation temperatures and lower activation Gibbs free energies. Dynamic studies, which embraced the combustion of diesel/biodiesel blends containing different amounts of the solubilized complex in a stationary motor, allowed a comparative evaluation of the soot emission through diffuse reflectance spectroscopy. These analyses provided very emphatic evidences of the efficiency of this new cerium complex for the control of soot emission in diesel/biodiesel motors. (c) 2009 Published by Elsevier B.V.

Constancy check of beam quality in conventional diagnostic X-ray equipment

A tandem ionization chamber was developed for quality control programs of X-ray equipment used in conventional radiography and mammography. A methodology for the use of the tandem chamber in the constancy check of diagnostic X-ray beam qualities was established. The application at a medical X-ray imaging facility of this established methodology is presented. The use of the tandem chamber in the constancy check of diagnostic X-ray beam qualities is a useful method to control the performance of the X-ray equipment. (c) 2008 Elsevier Ltd. All rights reserved.

Luminescent Langmuir-Blodgett film of a new amphiphilic Eu(3+) beta-diketonate

This work reports on the synthesis and characterization of the ligand 3-hexadecylpentane-2,4-drone (Hhdacac) and its Eu(3+) complexes Eu(hdacac)(6) center dot 2H(2)O, Eu(hdacac)(6) center dot phen and Eu(hdacac)(6) center dot tta, where phen and tta denote 1,10-phenanthroline and thenoyltrifluoroacetone, respectively. These new compounds present long carbon chains and their expected miscibility into non-polar ambients is confirmed by the emission spectra of Eu(hdacac)6 center dot tta in hexane. Moreover, the amphiphilic properties of Eu(hdacac)6 complexes allow the obtainment of thin luminescent films by the Langmuir-Blodgett technique. In both cases (solids and films), the typical antenna effect of beta-diketonates is observed. The alluring characteristics of these compounds raise great interest in many fields of Materials Science, like photo- and electro-luminescent materials (mainly thin ""organic"" films), metal catalysts or probes in non-polar solutions, and Langmuir-Blodgett films of several compositions. For the characterization of these products, nuclear magnetic resonance spectroscopy ((1)H NMR), thermogravimetric analysis, elementary analyses (C, H), scanning electron microscopy (energy dispersive X-ray spectroscopy), absorption (UV-vis/FT-IR) and photoluminescence spectroscopies were used. (c) 2008 Elsevier B.V. All rights reserved.

Quantification of orientation of pore patterns in X-ray images of deformed clay

The use of X-ray imaging to assess variability in ceramic fabrication is common in archaeological studies aimed at examining ancient pottery technologies. In this paper, a method based on the measurement of individual pores orientation is presented. This method is successfully applied to ceramic specimens of known origin whose structure signified different deformation histories.

Macromolecular assembly of polycystin-2 intracytosolic C-terminal domain

Mutations in PKD2 are responsible for approximately 15% of the autosomal dominant polycystic kidney disease cases. This gene encodes polycystin-2, a calcium-permeable cation channel whose C-terminal intracytosolic tail (PC2t) plays an important role in its interaction with a number of different proteins. In the present study, we have comprehensively evaluated the macromolecular assembly of PC2t homooligomer using a series of biophysical and biochemical analyses. Our studies, based on a new delimitation of PC2t, have revealed that it is capable of assembling as a homotetramer independently of any other portion of the molecule. Our data support this tetrameric arrangement in the presence and absence of calcium. Molecular dynamics simulations performed with a modified all-atoms structure-based model supported the PC2t tetrameric assembly, as well as how different populations are disposed in solution. The simulations demonstrated, indeed, that the best-scored structures are the ones compatible with a fourfold oligomeric state. These findings clarify the structural properties of PC2t domain and strongly support a homotetramer assembly of PC2.

Structural and electron self-exchange rate variations in isomeric (hexaamine)cobalt(III/II) complexes

The syntheses and characterisation of the new macrocyclic hexaamine trans-(5(S),7(S),12(R),14(R)-tetramethyl)-1,4,8,11-tetraazacyclotetradecane-6,13-diamine (L-6) and its Co-III complex are reported. The X-ray crystal structural analyses of [CoL6]Cl-2(ClO4) [monoclinic, space group C2/c, a = 16.468(3) Angstrom, b = 9.7156(7) Angstrom, c = 15.070(3) Angstrom, beta = 119.431(8)degrees, Z = 4] and the closely related cis-diamino-substituted macrocyclic complex [CoL2](ClO4)(3) . 2H(2)O (L-2 = cis-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine) [orthorhombic, space group Pna2(1), a = 16.8220(8) Angstrom, b = 10.416(2) Angstrom, c = 14.219(3) Angstrom, Z = 4] reveal significant variations in the observed Co-N bond lengths and coordination geometries, which may be attributed to the trans or cis disposition of the pendent primary amines. The Co-III/II self-exchange electron transfer rate constants for these and other closely related hexaamines have been determined, and variations of some 2 orders of magnitude are found between pairs of trans and cis isomeric Co-III complexes.

CLASSIFYING RADIUS FRACTURES WITH X-RAY AND TOMOGRAPHY IMAGING

Introduction: This study evaluated the interobserver reliability of plain radiograpy versus computed tomography (CT) for the Universal and AO classification systems for distal radius fractures. Patients and methods: Five observers classified 21 sets of distal radius fractures using plain radiographs and CT independently. Kappa statistics were used to establish a relative level of agreement between observers for both readings. Results: Interobserver agreement was rated as moderate for the Universal classification and poor for the AO classification. Reducing the AO system to 9 categories and to its three main types reliability was raised to a ""moderate"" level. No difference was found for interobserver reliability between the Universal classification using plain radiographs and the Universal classification using computed tomography. Interobserver reliability of the AO classification system using plain radiographs was significantly higher than the interobserver reliability of the AO classification system using only computed tomography. Conclusion: From these data, we conclude that classification of distal radius fractures using CT scanning without plain radiographs is not beneficial.

Pleural fluid: Are temperature and storage time critical preanalytical error factors in biochemical analyses?

Background: Biochemical analysis of fluid is the primary laboratory approach hi pleural effusion diagnosis. Standardization of the steps between collection and laboratorial analyses are fundamental to maintain the quality of the results. We evaluated the influence of temperature and storage time on sample stability. Methods: Pleural fluid from 30 patients was submitted to analyses of proteins, albumin, lactic dehydrogenase (LDH), cholesterol, triglycerides, and glucose. Aliquots were stored at 21 degrees, 4 degrees, and-20 degrees C, and concentrations were determined after 1, 2, 3, 4, 7, and 14 days. LDH isoenzymes were quantified in 7 random samples. Results: Due to the instability of isoenzymes 4 and 5, a decrease in LDH was observed in the first 24 h in samples maintained at -20 degrees C and after 2 days when maintained at 4 degrees C. Aside from glucose, all parameters were stable for up to at least day 4 when stored at room temperature or 4 degrees C. Conclusions: Temperature and storage time are potential preanalytical errors in pleural fluid analyses, mainly if we consider the instability of glucose and LDH. The ideal procedure is to execute all the tests immediately after collection. However, most of the tests can be done in refrigerated sample;, excepting LDH analysis. (C) 2010 Elsevier B.V. All rights reserved.

Reticular angiomatoid ""malignant"" fibrous histiocytoma-a case report with cytogenetics and molecular genetic analyses

Angiomatoid ""malignant"" fibrous histiocytoma is a rare sarcoma of low malignant potential that occurs most commonly in the extremities of children and young adults. Herein, we present a case of angiomatoid malignant fibrous histiocytoma with unusual histologic features arising in the mediastinum of an 80-year-old man. The tumor exhibited a reticular growth pattern and myxoid stroma. The tumor cells expressed epithelial membrane antigen and desmin. Cytogenetic analysis revealed the translocation t(2;22)(q33;q12). Molecular genetic analysis confirmed the rearrangement of the EWSR1 locus and the presence of the EWSR1/CREB1 fusion. This report expands the clinicopathologic spectrum of angiomatoid malignant fibrous histiocytoma and underscores the value of integrating morphologic, immunophenotypic, and molecular findings in the identification of its unusual morphologic variants. (C) 2011 Elsevier Inc. All rights reserved.

Effect of treadmill exercise on lumbar vertebrae in ovariectomized rats: anthropometrical and mechanical analyses

The purpose of this study was to examine the preventive effect of exercise on lumbar vertebrae in ovariectomized rats. Three-month-old female Wistar rats were divided into 3 groups: control group (A, n = 10); non-exercised ovariectomized group (B, n = 7) and exercised ovariectomized group (C, n = 7). The rats from group C were subjected to treadmill exercise (15 m/minute in the initial six weeks and 19 m/minute in the next six weeks, 1 hour/day, 4 days/week) for 12 weeks. At death, the fourth lumbar vertebrae were removed and an anthropometrical analysis by a paquimeter and a mechanical compression test by a universal test machine were performed. After 12 weeks, the ovariectomy decreased the superior-inferior vertebral height and the maximal braking load in group B compared to group A, while the exercise increased the vertebral mass in group C compared to both groups A and B (p < 0.01) and the stiffness compared to group B. We concluded the physical activity has an important role to prevent the osteopenia in lumbar vertebrae.