Reduced face preference in infancy: a developmental precursor to callous-unemotional traits?

Background Children with callous-unemotional (CU) traits, a proposed precursor to adult psychopathy, are characterized by impaired emotion recognition, reduced responsiveness to others’ distress, and a lack of guilt or empathy. Reduced attention to faces, and more specifically to the eye region, has been proposed to underlie these difficulties, although this has never been tested longitudinally from infancy. Attention to faces occurs within the context of dyadic caregiver interactions, and early environment including parenting characteristics has been associated with CU traits. The present study tested whether infants’ preferential tracking of a face with direct gaze and levels of maternal sensitivity predict later CU traits. Methods Data were analyzed from a stratified random sample of 213 participants drawn from a population-based sample of 1233 first-time mothers. Infants’ preferential face tracking at 5 weeks and maternal sensitivity at 29 weeks were entered into a weighted linear regression as predictors of CU traits at 2.5 years. Results Controlling for a range of confounders (e.g., deprivation), lower preferential face tracking predicted higher CU traits (p = .001). Higher maternal sensitivity predicted lower CU traits in girls (p = .009), but not boys. No significant interaction between face tracking and maternal sensitivity was found. Conclusions This is the first study to show that attention to social features during infancy as well as early sensitive parenting predict the subsequent development of CU traits. Identifying such early atypicalities offers the potential for developing parent-mediated interventions in children at risk for developing CU traits.

Improving polymeric microemulsions with block copolymer polydispersity

Recent experiments have demonstrated that block copolymers are capable of stabilizing immiscible homopolymer blends producing bicontinuous microemulsion. The stability of these polymeric alloys requires the copolymer to form flexible, nonattractive monolayers along the homopolymer interfaces. We predict that copolymer polydispersity can substantially and simultaneously improve the monolayers in both of these respects. Furthermore, polydispersity should provide similar improvements in systems, such as colloidal suspensions and polymer/clay composites, that utilize polymer brushes to suppress attractive interactions.

Administration of Neural Precursor Cells Ameliorates Renal Ischemia-Reperfusion Injury

In this study we evaluated whether administration of stem cells of neural origin (neural precursor cells, NPCs) could be protective against renal ischemia-reperfusion injury (IRI). We hypothesized that stem cell outcomes are not tissue-specific and that NPCs can improve tissue damage through paracrine mechanisms, especially due to immunomodulation. To this end, Wistar rats (200-250 g) were submitted to 1-hour ischemia and treated with NPCs (4 x 10(6) cells/animal) at 4 h of reperfusion. To serve as controls, ischemic animals were treated with cerebellum homogenate harvested from adult rat brain. All groups were sacrificed at 24 h of reperfusion. NPCs were isolated from rat fetus telencephalon and cultured until neurosphere formation (7 days). Before administration, NPCs were labeled with carboxyfluorescein diacetate succinimydylester (CFSE). Kidneys were harvested for analysis of cytokine profile and macrophage infiltration. At 24 h, NPC treatment resulted in a significant reduction in serum creatinine (IRI + NPC 1.21 + 0.18 vs. IRI 3.33 + 0.14 and IRI + cerebellum 2.95 + 0.78mg/dl, p < 0.05) and acute tubular necrosis (IRI + NPC 46.0 + 2.4% vs. IRI 79.7 + 14.2%, p < 0.05). NPC-CFSE and glial fibrillary acidic protein (GFAP)-positive cells (astrocyte marker) were found exclusively in renal parenchyma, which also presented GFAP and SOX-2 (an embryonic neural stem cell marker) mRNA expression. NPC treatment resulted in lower renal proinflammatory IL1-beta and TNF-alpha expression and higher anti-inflammatory IL-4 and IL-10 transcription. NPC-treated animals also had less macrophage infiltration and decreased serum proinflammatory cytokines (IL-1 beta, TNF-alpha and INF-gamma). Our data suggested that NPC therapy improved renal function by influencing immunological responses. Copyright (C) 2009 S. Karger AG, Basel

Magnetic characterization of ferrihydrite nanoparticles synthesized by hydrolysis of Fe metal-organic precursor

We investigate the formation of ferrihydrite nanoparticles (NPs) by hydrolysis of the Fe(III) alkoxide Fe(O(t)Bu)(3). Controlled amounts of water, up to 3.0 vol%, were added to the precursor solution yielding a series of hydrolyzed samples ranging from P0.0 (the unreacted precursor) to P3.0. X-ray diffraction (XRD) analysis evidenced the formation of high-crystalline ferrihydrite NP in sample P3.0, with grain size estimate of about 3.2 nm. The transition from the molecular precursor to the formation of crystalline magnetic NPs was followed through magnetization measurements M(T) and M(H), as well as Mossbauer spectroscopy (MS). M(T) measurements indicate a paramagnetic (PM) behavior for sample P0.0, characteristic of binuclear Fe-O-Fe units, which evolves to a superparamagnetic (SPM) behavior, with an energy barrier for the blocking process estimated for sample P3.0 as E(a) = 4.9 x 10(-21) J (E(a)/k(B) = 355 K), resulting in a high effective anisotropy constant K(eff) = 290 kJ/m(3). Magnetization loops at 5 K progressively change from PM-like to ferromagnetic-like shape upon increasing the hydrolysis process, although hysteresis (H(c) approximate to 500 Oe) only is apparent for P2.0 and higher. MS spectra at room temperature are PM/SPM doublets for all samples, while the MS spectra at T = 4.2 K reveal increasingly well-defined magnetic ordering as hydrolysis of the precursor stepwise progresses until well-crystallized ferrihydrite particles are formed. (C) 2008 Elsevier B.V. All rights reserved.

Synthesis and characterization of NiMn(2)O(4) nanoparticles using gelatin as organic precursor

Nanoparticles of NiMn(2)O(4) were successfully obtained by mixing gelatin and inorganic salts NiCl(2) center dot 6H(2)O and MnCl(2) center dot 4H(2)O in aqueous solution. The mixture has been synthesized at different temperatures and resulted in NiMn(2)O(4) nanoparticles with crystallites size in the range of 14-44 nm, as inferred from X-ray powder diffraction (XRPD) data. We have also observed that both the average crystallite size and the unit cell parameters increase with increasing synthesis temperature. Magnetic measurements confirmed the presence of a magnetic transition near 110K. (C) 2008 Published by Elsevier B.V.

Modeling Adsorption Processes of Poly-p-phenylenevinylene Precursor and Sodium Acid Dodecylbenzenesulfonate onto Layer-by-Layer Films Using a Langmuir-type Metastable Equilibrium Model

The adsorption kinetics curves of poly(xylylidene tetrahydrothiophenium chloride) (PTHT), a poly-p-phenylenevinylene (PPV) precursor, and the sodium salt of dodecylbenzene sulfonic acid (DBS), onto (PTHT/DBS)(n) layer-by-layer (LBL) films were characterized by means of UV-vis spectroscopy. The amount of PTHT/DBS and PTHT adsorbed on each layer was shown to be practically independent of adsorption time. A Langmuir-type metastable equilibrium model was used to adjust the adsorption isotherms data and to estimate adsorption/desorption coefficients ratios, k = k(ads)/k(des), values of 2 x 10(5) and 4 x 10(6) for PTHT and PTHT/DBS layers, respectively. The desorption coefficient has been estimated, using literature values for poly(o-methoxyaniline) desorption coefficient, as was found to be in the range of 10(-9) to 10(-6) s(-1), indicating that quasi equilibrium is rapidly attained.

Laser microstructuring for fabricating superhydrophobic polymeric surfaces

In this paper we show the fabrication of hydrophobic polymeric surfaces through laser microstructuring. By using 70-ps pulses from a Q-switched and mode-locked Nd:YAG laser at 532 nm, we were able to produce grooves with different width and separation, resulting in square-shaped pillar patterns. We investigate the dependence of the morphology on the surface static contact angle for water, showing that it is in agreement with the Cassie-Baxter model. We demonstrate the fabrication of a superhydrophobic polymeric surface, presenting a water contact angle of 157 degrees. The surface structuring method presented here seems to be an interesting option to control the wetting properties of polymeric surfaces. (C) 2010 Elsevier B.V. All rights reserved.

Polymeric scaffolds for enhanced stability of melanin incorporated in liposomes

The use of melanin in bioinspired applications is mostly limited by its poor stability in solid films. This problem has been addressed here by incorporating melanin into dipalmitoyl phosphatidyl glycerol (DPPG) liposomes, which were then immobilized onto a solid substrate as an LbL film. Results from steady-state and time-resolved fluorescence indicated an increased stability for melanin incorporated into DPPG liposomes. If not protected by liposomes, melanin looses completely its fluorescence properties in LbL films. The thickness of the liposome-melanin layer obtained from neutron reflectivity data was 4.1 +/- 0.2 nm, consistent with the value estimated for the phospholipid bilayer of the liposomes, an evidence of the collapse of most liposomes. On the other hand, the final roughness indicated that some of the liposomes had their structure preserved. In summary, liposomes were proven excellent for encapsulation, thus providing a suitable environment, closer to the physiological conditions without using organic solvents or high pHs. (C) 2010 Elsevier Inc. All rights reserved.

Synthesis and structural characterization of a new polymeric zinc(II) complex with thiophene-2-carboxylic acid

A new polymeric zinc(II) complex with thiophene-2-carboxylic acid (-tpc) of composition [Zn2(C20H12O8S4)]n was obtained and structurally characterized by X-ray diffraction, thermal analysis, nuclear magnetic resonance (NMR), and infrared spectroscopies. Upfield shift in the 1H-NMR spectrum is explained by the crystalline structure, which shows the thiophene rings overlapping each other in parallel pairs. The compound crystallizes in the monoclinic system, space group P21/c, with a = 9.7074(4) angstrom, b = 13.5227(3) angstrom, c = 18.9735(7) angstrom, = 95.797(10)degrees, and Z = 4. Three -tpc groups bridge between two Zn(II) ions through oxygens and the fourth one bridges between one of these ions and the third one, symmetry related by a twofold screw axis. This arrangement gives rise to infinite chains along the crystallographic a direction. The metal atoms display an approximate tetrahedral configuration. The complex is insoluble in water, ethanol, and acetone, but soluble in dimethyl sulfoxide.

CeO(2)-catalyzed ozonation of phenol

Three different cerium citrate-based precursors were used for synthesizing CeO(2) through thermal treatment. Three morphological types of CeO(2) were obtained. Characterization of these oxides was carried out by XRD patterns, SEM microscopy, N(2) adsorption isotherms, Raman spectroscopy, zeta potential, and UV/Vis luminescence. Ozonation of phenol catalyzed by CeO(2) was studied as a representative reaction of environmental interest. The differences on the catalytic activity showed by these three oxides could be correlated to amounts of Ce(3+) on CeO(2) surface and, consequently, to the demand for oxygen needed to burn each precursor.

Kinetic resolution of a drug precursor by Burkholderia cepacia lipase immobilized by different methodologies on superparamagnetic nanoparticles

Burkholderia cepacia lipase was immobilized on superparamagnetic nanoparticles using three different methodologies (adsorption, chemisorption with carboxibenzaldehyde and chemisorption with glutaraldehyde) and employed in the kinetic resolution of a chiral drug precursor, (RS)-2-bromo-1-(phenyl)ethanol, via enantioselective acetylation reaction. An excellent improvement of lipase catalytical performance was observed. Free B. cepacia lipase gave the ester (S)-2 with poor E-value <30, and after its immobilization to magnetic nanoparticles the E-value was up to >200. The effect of several reaction parameters in the kinetic resolution was studied. The best results for kinetic resolution were obtained using vinyl acetate as acetyl donor and toluene as solvent, typically yielding the ester in high enantiomeric excess (>99%) and E-value (E > 200). Of the three tested immobilization methods, chemisorption with glutaraldehyde was the best one in terms of temperature stability and yield product. (C) 2010 Elsevier B.V. All rights reserved.

Ruthenium nanoparticles prepared from ruthenium dioxide precursor: Highly active catalyst for hydrogenation of arenes under mild conditions

The hydrogenation of benzene and benzene derivatives was studied using Ru(0) nanoparticles prepared by a very simple method based on the in situ reduction of the commercially available precursor ruthenium dioxide under mild conditions (75 degrees C and hydrogen pressure 4atm) in imidazolium ionic liquids. Total turnovers (TTO) of 2700 mol/mol Ru were obtained for the conversion of benzene to cyclohexane under solventless conditions and TTO of 1200 mol/mol Ru were observed under ionic liquid biphasic conditions. When corrected for exposed ruthenium atoms, TTO values of 7940 (solventless) and 3530 (biphasic) were calculated for benzene hydrogenation. These reaction rates are higher than those observed for Ru nanoparticles prepared from decomposition of an organometallic precursor in similar conditions. The presence of the partially hydrogenated product cyclohexene was also detected at low conversion rates. (C) 2008 Elsevier B.V. All rights reserved.

Polymeric electronic gas sensor for determining alcohol content in automotive fuels

In this paper we describe the electrosynthesis of poly[(2-bromo-5-hexyloxy- 1,4-phenylenevinylene)-co-(1,4-phenylenevinylene)] (BHPPV-co-PPV), a novel conducting copolymer, and its application as active layer of a chemiresistive gas sensor suitable for quantification of ethanol present in ethanol-gasoline mixtures normally present in the fuel tanks of flex-fuel vehicles. This information is crucial for the smooth operation of the engine since it permits optimal air:fuel ratio regulation. The sensor consists of an interdigitated electrode coated with a thin polymer film doped with dodecylbenzenesulfonic acid. On exposure to fuel vapours at room temperature, the device presents a linear correlation between its electrical conductance and the ethanol concentration in the fuel. (C) 2008 Elsevier B.V. All rights reserved.

Polymeric electro-mechanic devices applied to antibiotic-controlled release

Polymeric electroactive blends formed by electropolymerized aniline inside a non-conductive polyacrylamide porous matrix were already shown as suitable materials for the electrocontrolled release of model compounds like safranin. In this paper the intermolecular interactions between the two components of the blend are put in evidence by Raman spectroscopy measurements. Also, in situ optical microscopy was used to follow changes occurring in the polyaniline/polyacrylamide blend during pyrocathecol violet release tests. These two sets of experiments show the possibility of controlling electrochemically the release of both, safranin (a cation) and pyrocathecol violet (an anion) and allow to infer a release mechanism based on the electromechanical properties of the blends explaining the dependence of the release kinetics on the applied potential. Tetracycline release curves for different potentials and pHs are shown and the obtained profiles are in agreement with those expected for a device acting as an electrochemically driven pump due to the artificial muscle properties of the conducting phase of the blends. (c) 2007 Elsevier B.V. All rights reserved.