Teores de enxofre em solos dos Estados do Rio de Janeiro e Espírito Santo.

bitstream/CNPS-2009-09/11269/1/comtec19_2003_teores_enxofre.pd

Design Rules for Self-Assembly of 2D Nanocrystal/Metal-Organic Framework Superstructures.

We demonstrate the guiding principles behind simple two dimensional self-assembly of MOF nanoparticles (NPs) and oleic acid capped iron oxide (Fe3 O4 ) NCs into a uniform two-dimensional bi-layered superstructure. This self-assembly process can be controlled by the energy of ligand-ligand interactions between surface ligands on Fe3 O4 NCs and Zr6 O4 (OH)4 (fumarate)6 MOF NPs. Scanning transmission electron microscopy (TEM)/energy-dispersive X-ray spectroscopy and TEM tomography confirm the hierarchical co-assembly of Fe3 O4 NCs with MOF NPs as ligand energies are manipulated to promote facile diffusion of the smaller NCs. First-principles calculations and event-driven molecular dynamics simulations indicate that the observed patterns are dictated by combination of ligand-surface and ligand-ligand interactions. This study opens a new avenue for design and self-assembly of MOFs and NCs into high surface area assemblies, mimicking the structure of supported catalyst architectures, and provides a thorough fundamental understanding of the self-assembly process, which could be a guide for designing functional materials with desired structure

Quantitative And Qualitative Analysis Of Microorganisms In Root-filled Teeth With Persistent Infection: Monitoring Of The Endodontic Retreatment.

The aim of this study was to investigate in vivo microorganisms detected in root-filled teeth with post-treatment apical periodontitis and quantify colony-forming units (CFU) during endodontic retreatment. Fifteen root-filled teeth had their previous gutta-percha removed and were randomly instrumented before being divided into three groups and medicated with either [Ca(OH)2 + 2% CHX gel], [Ca(OH)2 + 0.9% NaCl] or 2% CHX gel. Samples were taken after removal of gutta-percha (S1), after chemomechanical preparation using 2% CHX gel (S2), and after inter-appointment dressing (S3) for 7 or 14 days later. Cultivable bacteria recovered from infected root canals at the three stages were counted and identified by means of culture and PCR assay (16S rDNA). Quantitative data were statistically analyzed by using Mann-Whitney test in which pairs of groups were compared (P < 0.05). CFU counts decreased significantly from S1 to S2 (P < 0.05). No significant difference was found between S2 and S3 (P = 0.3093) for all three experimental groups. Chemomechanical preparation and intra-canal dressing promoted significant median reductions of 99.61% and 99.57%, respectively, in the number of bacteria compared to S1 samples. A total of 110 cultivable isolates were recovered by culture technique from 32 different species and 7 different genera. Out of the 13 target species-specific primer of bacteria analyzed, 11 were detected during endodontic retreatment. The great majority of taxa found in post-treatment samples were Gram-positive bacteria, although Gram-negative bacteria were found by molecular methods. Moreover, our results showed that gutta-percha removal and chemomechanical preparation are effective for root canal disinfection, whereas additional intra-canal dressing did not improve disinfection.7302-

Psychogenetics of Turner syndrome: an investigation of 28 subjects and respective controls using the Bender test and Piagetian scales

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Piagetian scales and the Bender visual motor gestalt test (BT) were applied to 28 subjects with universal 45, X Turner syndrome (TS), and their respective controls, in order to investigate their cognitive performance. Dermatoglyphics were also analyzed to obtain clues concerning embryological changes that may have appeared during development of the nervous system and could be associated with cognitive performance of TS patients. Dermatoglyphic pattern distribution was similar to that reported in previous studies of TS individuals: ulnar loops in the digital patterns and finger ridge, a-b, and A'-d counts were more frequent, while arch and whorl patterns were less frequent compared to controls. However, we did not find higher frequencies of hypothenar pattern, maximum atd angle, and ulnarity index in our TS subjects, unlike other investigations. Furthermore, we found significant differences between TS and control T line index values. The BT scores were also lower in probands, as has been previously reported, revealing a neurocognitive deficit of visual motor perception in TS individuals, which could be due to an absence of, or deficiency in, cerebral hemispheric lateralization. However, TS subjects seemed to improve their performance on BT with age. Cognitive performance of the TS subjects was not significantly different from that of controls, confirming a previous study in which TS performance was found to be similar to that of the normal Brazilian population. There were significant correlations between BT scores and Piagetian scale levels with dermatoglyphic parameters. This association could be explained by changes in the common ectodermal origin of the epidermis and the central nervous system. TS subjects seem to succeed in compensating their spatial impairments in adapting their cognitive and social contacts. We concluded that genetic counseling should consider cognitive and psychosocial difficulties presented by TS subjects, providing appropriate treatment and orientation for them and their families.9317011725Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq_Brasi

Children’s coping styles and trauma symptoms after an explosion disaster

Background: The negative impact of trauma on children and adolescents is well documented. However, few studies have investigated the relationship between coping and trauma and distress symptoms after man-made disasters, especially those not related to war. Objective: This study investigated the relationship between children’s coping styles and their self-reported levels of trauma and distress symptoms after an explosion disaster in a residential area. Method: Participants were recruited through the local public school that served the affected residential area. A total of 333 children and adolescents from grades 3 through 10 participated in the study 16 months after the explosion. All participants filled out questionnaires to assess their trauma and distress symptoms as well as their coping strategies. The adolescents answered additional questions about pre-, peri-, and post-traumatic factors and filled out questionnaires about their trauma and distress symptoms, including aspects of somatization and negative affectivity. Results: The following variables were associated with a higher degree of trauma symptoms for children in grades 6 through 10 and explained 39% to 48% of the unique variance in these symptoms: female gender; the experience of traumatic events pre-disaster; the destruction of property or danger to life occurring during the disaster; the experience of traumatic events post-disaster; and the use of self-blame, emotion regulation, wishful thinking, and cognitive restructuring. For the younger children, pre-, peri-, and post-disaster factors were not measured. However, female gender and the use of self-blame as a coping strategy explained 26% of the variance in trauma symptoms. Conclusions: This study generally supports the findings of the limited literature addressing coping skills after man-made disasters. However, contrary to previous findings in community samples after episodes of terrorism, adaptive coping strategies such as cognitive restructuring were found to influence the variance of trauma and distress symptoms

A Mechanistic Analysis of Phase Evolution and Hydrogen Storage Behavior in Nanocrystalline Mg(BH4)2 within Reduced Graphene Oxide.

Magnesium borohydride (Mg(BH4)2, abbreviated here MBH) has received tremendous attention as a promising onboard hydrogen storage medium due to its excellent gravimetric and volumetric hydrogen storage capacities. While the polymorphs of MBH-alpha (α), beta (β), and gamma (γ)-have distinct properties, their synthetic homogeneity can be difficult to control, mainly due to their structural complexity and similar thermodynamic properties. Here, we describe an effective approach for obtaining pure polymorphic phases of MBH nanomaterials within a reduced graphene oxide support (abbreviated MBHg) under mild conditions (60-190 °C under mild vacuum, 2 Torr), starting from two distinct samples initially dried under Ar and vacuum. Specifically, we selectively synthesize the thermodynamically stable α phase and metastable β phase from the γ-phase within the temperature range of 150-180 °C. The relevant underlying phase evolution mechanism is elucidated by theoretical thermodynamics and kinetic nucleation modeling. The resulting MBHg composites exhibit structural stability, resistance to oxidation, and partially reversible formation of diverse [BH4]- species during de- and rehydrogenation processes, rendering them intriguing candidates for further optimization toward hydrogen storage applications