Influence de la taille de départ, de l’état d’agglomération et de la dose de nanoparticules de dioxyde de titane (TiO2) inhalées sur la réponse pulmonaire chez le rat

En raison de leur petite taille, les nanoparticules (NP) (< 100 nm) peuvent coaguler très rapidement ce qui favorise leur pénétration dans l’organisme sous forme d’agglomérats. L’objectif de cette recherche est d’étudier l’influence de l’état d’agglomération de NP de dioxyde de titane (TiO2) de trois tailles de départ différentes, 5, 10-30 ou 50 nm sur la toxicité pulmonaire chez le rat mâle (F344) exposé à des aérosols de 2, 7 ou 20 mg/m3 pendant 6 heures. Dans une chambre d’inhalation, six groupes de rats (n = 6 par groupe) ont été exposés par inhalation aiguë nez-seulement à des aérosols ayant une taille primaire de 5 nm, mais produits sous forme faiblement (< 100 nm) ou fortement (> 100 nm) agglomérée à 2, 7 et 20 mg/m3. De façon similaire, quatre autres groupes de rats ont été exposés à 20 mg/m3 à des aérosols ayant une taille primaire de 10-30 et 50 nm. Les différents aérosols ont été générés par nébulisation à partir de suspensions ou par dispersion à sec. Pour chaque concentration massique, un groupe de rats témoins (n = 6 par groupe) a été exposé à de l’air comprimé dans les mêmes conditions. Les animaux ont été sacrifiés 16 heures après la fin de l’exposition et les lavages broncho-alvéolaires ont permis de doser des marqueurs d’effets inflammatoires, cytotoxiques et de stress oxydant. Des coupes histologiques de poumons ont également été analysées. L’influence de l’état d’agglomération des NP de TiO2 n’a pu être discriminée à 2 mg/m3. Aux concentrations massiques de 7 et 20 mg/m3, nos résultats montrent qu’une réponse inflammatoire aiguë est induite suite à l'exposition aux aérosols fortement agglomérés. En plus de cette réponse, l’exposition aux aérosols faiblement agglomérés à 20 mg/m3 s’est traduite par une augmentation significative de la 8-isoprostane et de la lactate déshydrogénase. À 20 mg/m3, les effets cytotoxiques étaient plus importants suite à l’exposition aux NP de 5 nm faiblement agglomérées. Ces travaux ont montré dans l'ensemble que différents mécanismes de toxicité pulmonaire peuvent être empruntés par les NP de TiO2 en fonction de la taille de départ et de l’état d’agglomération.

Electrical, optical, and structural studies of shallow-buried Au-polymethylmethacrylate composite films formed by very low energy ion implantation

The authors present here a summary of their investigations of ultrathin films formed by gold nanoclusters embedded in polymethylmethacrylate polymer. The clusters are formed from the self-organization of subplantated gold ions in the polymer. The source of the low energy ion stream used for the subplantation is a unidirectionally drifting gold plasma created by a magnetically filtered vacuum arc plasma gun. The material properties change according to subplantation dose, including nanocluster sizes and agglomeration state and, consequently also the material electrical behavior and optical activity. They have investigated the composite experimentally and by computer simulation in order to better understand the self-organization and the properties of the material. They present here the results of conductivity measurements and percolation behavior, dynamic TRIM simulations, surface plasmon resonance activity, transmission electron microscopy, small angle x-ray scattering, atomic force microscopy, and scanning tunneling microscopy. (C) 2010 American Vacuum Society [DOI: 10.1116/1.3357287]

Synthesis and sintering of ZrO2-CeO2 powder by use of polymeric precursor based on Pechini process

Nanocrystalline ZrO2-12 mol % CeO2 powders were synthesized using a polymeric precursor method based on the Pechini process. X-ray diffraction (XRD) patterns showed that the method was effective to synthesize tetragonal zirconia single-phase. The mean crystallite size attained ranges from 6 to 15 nm. The BET surface areas were relatively high reaching 97 m(2)/g. Studies by nitrogen adsorption/desorption on powders, dilatometry of the compacts, and transmission electron microscopy (TEM) of the powders, were also developed to verify the particles agglomeration state. Both citric acid : ethylene glycol ratio and calcination temperature affected the powder morphology, which influenced the sinterability and microstructure of the sintered material, as showed by scanning electron microscopy (SEM). (C) 2001 Kluwer Academic Publishers.

Effect of ceria content on the sintering of ZrO2 based ceramics synthesized from a polymeric precursor

Zirconia-ceria powders with ceria concentration varying from 0 to 12 mol% were synthesized using a polymeric precursor route based on the Pechini process. Powder characteristics were evaluated with regard to the crystallite size, BET surface area, phase distribution, nitrogen adsorption/desorption behavior, and agglomeration state. Sintering was studied considering the shrinkage rate, densification, grain size, and phase evolution. It was demonstrated that the synthesis method is effective to prepare nanosized powders of tetragonal zirconia single-phase. Sinterability mainly depended on the agglomeration state of powders and the monoclinic phase content, fully tetragonal zirconia ceramic, with grain size of 2.4 mu m, was obtained after addition of at least 9 mol% ceria and sintering at 1500 degrees C for 4 h. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

THE ROLE OF COLLOIDAL SILICON DIOXIDE IN THE ENHANCEMENT OF THE DRYING OF HERBAL PREPARATIONS IN SUSPENDED STATE

Recently, some research groups have been developing studies aiming to apply spouted beds of inert particles for production of dried herbal extracts. However, mainly due to their complex composition, several problems arise during the spouted bed drying of herbal extracts such as bed instability, product accumulation, particle agglomeration, and bed collapse. The addition of drying carriers, like colloidal silicon dioxide, to the extractive solution can minimize these unwanted effects. The aim of this work was to study the influence of the addition of colloidal silicon dioxide on enhancement of the performance of the drying of hydroalcoholic extract of Bauhinia forficata Link on a spouted bed of inert particles. The physical properties of the herbal extract and of its mixture with colloidal silicon dioxide at several concentrations (20% to 80% related to solids content) were quantified by determination of the surface tension, rheological properties, density, pH, and contact angles with the inert surfaces. Drying performance was evaluated through determination of the elutriation ratio, product recovery ratio, and product accumulation. The product was characterized through determination of the thermal degradation of bioactive compounds and product moisture content. The results indicated that the rheological properties of the extracts and their preparations, the contact angle with inert material, and the work of adhesion play important roles in the spouted bed drying of herbal extracts. Higher concentration of the drying carrier significantly improved the spouted bed drying performance.

IDENTIFICATION OF THE STATE OF A WET SPOUTED BED THROUGH TIME-FREQUENCY ANALYSIS OF PRESSURE FLUCTUATION TIME SERIES

The feasibility of detecting instability in wet spouted beds via pressure fluctuation (PF) time-series analyses was investigated. Experiments were carried out in a cylindrical Plexiglas column of diameter 150 mm with a conical base of internal angle 60 degrees, an inlet orifice diameter of 25 mm and glass beads of diameter 2.4 mm. Transducers at several axial positions measured PF time series with incremental addition of aqueous sucrose solutions of different concentrations. Liquid addition affected the spouted bed dynamics, causing irregular spouting, increased voidage in the annulus, increased fountain height, irregular annulus height, channelling, agglomeration, and adhesion of particles to the column walls. Autocorrelations indicated the appearance of periodicities in the PF signals with increasing sucrose addition. Dominant peaks in power-spectral density developed at low frequencies with changing system dynamics. The results indicate that PF signals furnish relevant information on system dynamics, useful for monitoring and control of spouted bed operations such as particle coating and drying of paste-like materials.

The third transformation of Japan: An institutional narrative on agglomeration economies in abenomics

Objective of the study The aim of this study is to understand the institutional implications in Abenomics in a spatial context, the contemporary economic reform taking place in Japan, which is to finally end over two decades of economic malaise. For theoretical perspective of choice, this study explores a synthesis of institutionalism as the main approach, complemented by economies of agglomeration in spatial economics, or New Economic Geography (NEG). The outcomes include a narrative with implications for future research, as well as possible future implications for the economy of Japan, itself. The narrative seeks to depict the dialogue between public discourse and governmental communication in order to create a picture of how this phenomenon is being socially constructed. This is done by studying the official communications by the Cabinet along with public media commentary on respective topics. The reform is studied with reference to historical socio-cultural, economic evolution of Japan, which in turn, is explored through a literature review. This is to assess the unique institutional characteristics of Japan pertinent to reform. Research method This is a social and exploratory qualitative study – an institutional narrative case study. The methodological approach was kept practical: in addition to literature review, a narrative, thematic content analysis with structural emphasis was used to construct the contemporary narrative based on the Cabinet communication. This was combined with practical analytic tools borrowed from critical discourse analysis, which were utilized to assess the implicit intertextual agenda within sources. Findings What appears to characterize the discourse is status quo bias that comes in multiple forms. The bias is also coded in the institutions surrounding the reform, wherein stakeholders have vested interests in protecting the current state of affairs. This correlates with uncertainty avoidance characteristic to Japan. Japan heeds the international criticism to deregulate on a rhetorical level, but consistent with history, the Cabinet solutions appear increasingly bureaucratic. Hence, the imposed western information-age paradigm of liberal cluster agglomeration seems ill-suited to Japan which lacks risk takers and a felicitous entrepreneur culture. The Japanese, however, possess vast innovative potential ascribed to some institutional practices and traits, but restrained by others. The derived conclusion is to study the successful intrapreneur cases in Japanese institutional setting as a potential benchmark for Japan specific cluster agglomeration, and a solution to its structural problems impeding growth.

Phylogenetics, Ancestral State Reconstruction, And A New Infrafamilial Classification Of The Pantropical Ochnaceae (medusagynaceae, Ochnaceae S.str., Quiinaceae) Based On Five Dna Regions.

Ochnaceae s.str. (Malpighiales) are a pantropical family of about 500 species and 27 genera of almost exclusively woody plants. Infrafamilial classification and relationships have been controversial partially due to the lack of a robust phylogenetic framework. Including all genera except Indosinia and Perissocarpa and DNA sequence data for five DNA regions (ITS, matK, ndhF, rbcL, trnL-F), we provide for the first time a nearly complete molecular phylogenetic analysis of Ochnaceae s.l. resolving most of the phylogenetic backbone of the family. Based on this, we present a new classification of Ochnaceae s.l., with Medusagynoideae and Quiinoideae included as subfamilies and the former subfamilies Ochnoideae and Sauvagesioideae recognized at the rank of tribe. Our data support a monophyletic Ochneae, but Sauvagesieae in the traditional circumscription is paraphyletic because Testulea emerges as sister to the rest of Ochnoideae, and the next clade shows Luxemburgia+Philacra as sister group to the remaining Ochnoideae. To avoid paraphyly, we classify Luxemburgieae and Testuleeae as new tribes. The African genus Lophira, which has switched between subfamilies (here tribes) in past classifications, emerges as sister to all other Ochneae. Thus, endosperm-free seeds and ovules with partly to completely united integuments (resulting in an apparently single integument) are characters that unite all members of that tribe. The relationships within its largest clade, Ochnineae (former Ochneae), are poorly resolved, but former Ochninae (Brackenridgea, Ochna) are polyphyletic. Within Sauvagesieae, the genus Sauvagesia in its broad circumscription is polyphyletic as Sauvagesia serrata is sister to a clade of Adenarake, Sauvagesia spp., and three other genera. Within Quiinoideae, in contrast to former phylogenetic hypotheses, Lacunaria and Touroulia form a clade that is sister to Quiina. Bayesian ancestral state reconstructions showed that zygomorphic flowers with adaptations to buzz-pollination (poricidal anthers), a syncarpous gynoecium (a near-apocarpous gynoecium evolved independently in Quiinoideae and Ochninae), numerous ovules, septicidal capsules, and winged seeds with endosperm are the ancestral condition in Ochnoideae. Although in some lineages poricidal anthers were lost secondarily, the evolution of poricidal superstructures secured the maintenance of buzz-pollination in some of these genera, indicating a strong selective pressure on keeping that specialized pollination system.

Emergent Antiferromagnetism Out Of The Hidden-order" State In Uru2si2: High Magnetic Field Nuclear Magnetic Resonance To 40 T."

Very high field (29)Si-NMR measurements using a fully (29)Si-enriched URu(2)Si(2) single crystal were carried out in order to microscopically investigate the hidden order (HO) state and adjacent magnetic phases in the high field limit. At the lowest measured temperature of 0.4 K, a clear anomaly reflecting a Fermi surface instability near 22 T inside the HO state is detected by the (29)Si shift, (29)K(c). Moreover, a strong enhancement of (29)K(c) develops near a critical field H(c) ≃ 35.6 T, and the ^{29}Si-NMR signal disappears suddenly at H(c), indicating the total suppression of the HO state. Nevertheless, a weak and shifted (29)Si-NMR signal reappears for fields higher than H(c) at 4.2 K, providing evidence for a magnetic structure within the magnetic phase caused by the Ising-type anisotropy of the uranium ordered moments.

[impact Variables On The Decline In Infant Mortality In The State Of São Paulo, Brazil: 1998-2008].

This is an ecological, analytical and retrospective study comprising the 645 municipalities in the State of São Paulo, the scope of which was to determine the relationship between socioeconomic, demographic variables and the model of care in relation to infant mortality rates in the period from 1998 to 2008. The ratio of average annual change for each indicator per stratum coverage was calculated. Infant mortality was analyzed according to the model for repeated measures over time, adjusted for the following correction variables: the city's population, proportion of Family Health Programs (PSFs) deployed, proportion of Growth Acceleration Programs (PACs) deployed, per capita GDP and SPSRI (São Paulo social responsibility index). The analysis was performed by generalized linear models, considering the gamma distribution. Multiple comparisons were performed with the likelihood ratio with chi-square approximate distribution, considering a significance level of 5%. There was a decrease in infant mortality over the years (p < 0.05), with no significant difference from 2004 to 2008 (p > 0.05). The proportion of PSFs deployed (p < 0.0001) and per capita GDP (p < 0.0001) were significant in the model. The decline of infant mortality in this period was influenced by the growth of per capita GDP and PSFs.

[diet Quality And Associated Factors Among The Elderly: A Population-based Study In Campinas, São Paulo State, Brazil].

The aim of this study was to assess the quality of diet among the elderly and associations with socio-demographic variables, health-related behaviors, and diseases. A population-based cross-sectional study was conducted in a representative sample of 1,509 elderly participants in a health survey in Campinas, São Paulo State, Brazil. Food quality was assessed using the Revised Diet Quality Index (DQI-R). Mean index scores were estimated and a multiple regression model was employed for the adjusted analyses. The highest diet quality scores were associated with age 80 years or older, Evangelical religion, diabetes mellitus, and physical activity, while the lowest scores were associated with home environments shared with three or more people, smoking, and consumption of soft drinks and alcoholic beverages. The findings emphasize a general need for diet quality improvements in the elderly, specifically in subgroups with unhealthy behaviors, who should be targeted with comprehensive strategies.

A New Species Of Pseudopaludicola Miranda-ribeiro, 1926 (anura: Leptodactylidae: Leiuperinae) From Northwestern State Of São Paulo, Brazil.

A new species of Pseudopaludicola is described from human-altered areas originally covered by Semideciduous Forest in northwestern state of São Paulo, southeastern Brazil. Morphologically, the new species differs from four species belonging to the P. pusilla group by the absence of either T-shaped terminal phalanges or toe tips expanded, and from all other congeners except P. canga and P. facureae by possessing an areolate vocal sac, with dark reticulation. The higher duration (300-700 ms) of each single, pulsed note (9-36 nonconcatenated pulses) that compose the call in the new species distinguishes it from all other 14 species of Pseudopaludicola with calls already described (10-290 ms). Absence of harmonics also differ the advertisement call of the new species from the call of its sister species P. facureae, even though these two species presented unexpected low genetic distances. Although we could not identify any single morphological character distinguishing the new species from P. facureae, a PCA and DFA performed using 12 morphometric variables evidenced significant size differences between these two species. 

Site Specific Spin Dynamics In Bafe2as2: Tuning The Ground State By Orbital Differentiation.

The role of orbital differentiation on the emergence of superconductivity in the Fe-based superconductors remains an open question to the scientific community. In this investigation, we employ a suitable microscopic spin probe technique, namely Electron Spin Resonance (ESR), to investigate this issue on selected chemically substituted BaFe2As2 single crystals. As the spin-density wave (SDW) phase is suppressed, we observe a clear increase of the Fe 3d bands anisotropy along with their localization at the FeAs plane. Such an increase of the planar orbital content is interestingly independent of the chemical substitution responsible for suppressing the SDW phase. As a consequence, the magnetic fluctuations in combination with this particular symmetry of the Fe 3d bands are propitious ingredients for the emergence of superconductivity in this class of materials.

Burnout Syndrome In Nursing Assistants Of A Public Hospital In The State Of São Paulo.

The burnout syndrome is a psychosocial phenomenon that arises as a response to chronic interpersonal stressors present at work. There are many aspects that make nursing assistants vulnerable to chronic stress situations that may lead to burnout, highlighting the low degree of autonomy in the healthcare staff and spending more in direct contact with patients. To assess the prevalence of the burnout syndrome in nursing assistants in a public hospital, as well as its association with socio-demographic and professional variables. A socio-demographic and professional questionnaire and the Maslach Burnout Inventory (MBI-SS) were applied to 534 nursing assistants. The prevalence of burnout syndrome among nursing assistants was 5.9%. High emotional exhaustion was observed in 23.6%, 21.9% showed high depersonalization, and 29.9% low professional achievement. It was found statistically significant associations between emotional exhaustion, job sector and marital status; depersonalization, having children and health problems; low professional achievement and job sector and number of jobs. There was association between job satisfaction and the three dimensions. Professionals working in the health area must pay intense and extended attention to people who are dependent upon others. The intimate contact of the nursing assistants with hard-to-handle patients, as well as being afraid to make mistakes in healthcare are additional chronic stress factors and burnout syndrome cases related in this study.

The Psychedelic State Induced By Ayahuasca Modulates The Activity And Connectivity Of The Default Mode Network.

The experiences induced by psychedelics share a wide variety of subjective features, related to the complex changes in perception and cognition induced by this class of drugs. A remarkable increase in introspection is at the core of these altered states of consciousness. Self-oriented mental activity has been consistently linked to the Default Mode Network (DMN), a set of brain regions more active during rest than during the execution of a goal-directed task. Here we used fMRI technique to inspect the DMN during the psychedelic state induced by Ayahuasca in ten experienced subjects. Ayahuasca is a potion traditionally used by Amazonian Amerindians composed by a mixture of compounds that increase monoaminergic transmission. In particular, we examined whether Ayahuasca changes the activity and connectivity of the DMN and the connection between the DMN and the task-positive network (TPN). Ayahuasca caused a significant decrease in activity through most parts of the DMN, including its most consistent hubs: the Posterior Cingulate Cortex (PCC)/Precuneus and the medial Prefrontal Cortex (mPFC). Functional connectivity within the PCC/Precuneus decreased after Ayahuasca intake. No significant change was observed in the DMN-TPN orthogonality. Altogether, our results support the notion that the altered state of consciousness induced by Ayahuasca, like those induced by psilocybin (another serotonergic psychedelic), meditation and sleep, is linked to the modulation of the activity and the connectivity of the DMN.