Cell and platelet composition assays by flow cytometry: basis for new platelet-rich fibrin methodologies.

Platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) are selective blood fractions obtained by cen¬trifugation. They act locally on inflammation and immunity as adjuvant homeostatic modulators during tissue regeneration. In recent years, many methods for achieving these blood concentrates have emerged, whose parameters of time and force of centrifugation presented themselves as critical, conflicting, and poorly understood points. Thus, the present study aimed to evaluate the effect of different centrifugal experimental parameters on the concentration of cells and platelets in samples of anticoagulated blood. Blood samples were centrifuged by forces of 200, 400 and 800 x g for 5, 10 and 15 minutes of centrifugation times to obtain three fractions: a) platelet-poor plasma (PPP), b) leukocyte-rich plasma (L- PRP) and c) red blood cell sed¬iment (RBC). The leukocyte and platelet content of each centrifuged fraction was measured by automated flow cytometry associated with the peroxidase reaction for differential leukocyte count. The application of 200 x g generated a more significant dispersive content of leukocytes and platelets in the supernatant fraction of PPP when compared to the other two strength ranges. However, it presented the highest concentration of platelets in the sediment (P <0.05 ANOVA), representing a loss of total mass during processing. The 400 and 800 x g forces showed leukocytes and platelets condensed in the L-PRP fraction and lower levels in the sedi¬ment, demonstrating the greater effectiveness of buoyancy in the resuspension of these sedimented elements. Our experimental data showed that the concentration and organization of leukocytes and platelets in the centrifuged blood matrices are very sensitive to variations in g force and centrifugation time, thus generating products with different biological composition and characteristics, and with specific potential therapeutic effects. The present study did not focus on comparing authoring methods, but on presenting the impact of methodological variations on the biological nature of centrifuged blood matrices. Further in vivo studies are needed to assess the specific clinical effect of each methodological change.

Computer-based quantification of an atraumatic sinus augmentation technique using CBCT.

Our group recently developed an innovative maxillary sinus augmentation technique without the need of sinus membrane elevation, termed as "IPG" DET protocol. This technique utilizes autologous platelet concentrates (including platelet rich plasma (PRP), platelet rich fibrin (PRF), growth factors (GFs) and CD34+ stem cells), together with bone grafting materials positioned through intentionally perforated Schneider's membrane for flapless implant placement. This study aimed at evaluating the performance of "IPG" DET protocol in terms of new bone formation and implant stability at 8 months post-op. This prospective study consisted of forty-eight patients with a mean age of 52.8 years. A total of eighty-five implants were placed with "IPG" DET protocol in combination with autologous platelet concentrates. CBCT (cone beam computed tomography) was performed at two different time points: pre-operatively and at 8 months post-op. CBCT images were then compared by an intensity-based image algorithm to assess the newly formed bone in terms of gray scale values. Additionally, implant stability quotient (ISQ) was used to estimate implant osseointegration and success rate. The average new bone formation was 5.9 ± 0.9 mm2 per implant. All implants successfully osseointegrated, and ISQ ranged 62.3-71.7. According to the results of this study, "IPG" DET protocol in combination with autologous platelet concentrates is a successful technique for implant-supported rehabilitation of the edentulous posterior maxilla without the need of sinus floor elevation.

Low toxicity superparamagnetic magnetite nanoparticles: One-pot facile green synthesis for biological applications.

Superparamagnetic magnetite nanoparticles have been synthesized by a highly reproducible polyvinyl alcohol (PVA)-based modified sol-gel process using water as the only solvent. The synthesis method has proven to be effective, time and cost saving and environmental friendly, resulting in PVA-coated magnetite nanoparticles as direct product from the synthesis, without any special atmosphere or further thermal treatment. X-ray diffraction and transmission electron microscopy revealed that the biocompatible PVA-coating prevents the nanoparticle agglomeration, giving rise to spherical crystals with sizes of 6.8nm (as-cast) and 9.5nm (heat treated) with great control over size and shape with narrow size distribution. Complementary compositional and magnetic characterizations were employed in order to study the surface chemistry and magnetic behavior of the samples, respectively. Cytotoxicity endpoints including no observed adverse effect concentration (NOAEC), 50% lethal concentration (LC50) and total lethal concentration (TLC) of the tested materials on cell viability were determined after 3, 24 and 48h of exposure. The PVA coating improved the biocompatibility of the synthesized magnetite nanoparticles showing good cell viability and low cytotoxicity effects on the MTT assay performed on BHK cells. Preliminary assessment of nanoparticles in vivo effects, performed after 48h on Balb/c mice, exposed to a range of different sub-lethal doses, showed their capacity to penetrate in liver and kidneys with no significant morphological alterations in both organs.

Dimensionality tuning of the electronic structure in Fe3Ga4 magnetic materials.

This work reports on the dimensionality effects on the magnetic behavior of Fe3Ga4 compounds by means of magnetic susceptibility, electrical resistivity, and specific heat measurements. Our results show that reducing the Fe3Ga4 dimensionality, via nanowire shape, intriguingly modifies its electronic structure. In particular, the bulk system exhibits two transitions, a ferromagnetic (FM) transition temperature at T1 = 50 K and an antiferromagnetic (AFM) one at T2 = 390 K. On the other hand, nanowires shift these transition temperatures, towards higher and lower temperature for T1 and T2, respectively. Moreover, the dimensionality reduction seems to also modify the microscopic nature of the T1 transition. Instead of a FM to AFM transition, as observed in the 3D system, a transition from FM to ferrimagnetic (FERRI) or to coexistence of FM and AFM phases is found for the nanowires. Our results allowed us to propose the magnetic field-temperature phase diagram for Fe3Ga4 in both bulk and nanostructured forms. The interesting microscopic tuning of the magnetic interactions induced by dimensionality in Fe3Ga4 opens a new route to optimize the use of such materials in nanostructured devices.

Bayesian GGE biplot models applied to maize multi-environments trials.

The additive main effects and multiplicative interaction (AMMI) and the genotype main effects and genotype x environment interaction (GGE) models stand out among the linear-bilinear models used in genotype x environment interaction studies. Despite the advantages of their use to describe genotype x environment (AMMI) or genotype and genotype x environment (GGE) interactions, these methods have known limitations that are inherent to fixed effects models, including difficulty in treating variance heterogeneity and missing data. Traditional biplots include no measure of uncertainty regarding the principal components. The present study aimed to apply the Bayesian approach to GGE biplot models and assess the implications for selecting stable and adapted genotypes. Our results demonstrated that the Bayesian approach applied to GGE models with non-informative priors was consistent with the traditional GGE biplot analysis, although the credible region incorporated into the biplot enabled distinguishing, based on probability, the performance of genotypes, and their relationships with the environments in the biplot. Those regions also enabled the identification of groups of genotypes and environments with similar effects in terms of adaptability and stability. The relative position of genotypes and environments in biplots is highly affected by the experimental accuracy. Thus, incorporation of uncertainty in biplots is a key tool for breeders to make decisions regarding stability selection and adaptability and the definition of mega-environments.

Audiometric findings in petrochemical workers exposed to noise and chemical agents.

This study investigated the occurrence of hearing loss among workers of a petrochemical industry during a period of five years. The records of environmental noise and solvents measurements and the results of annual audiometry performed by the company were examined. The audiometric results of workers from olefin operational areas 1 and 2 and aromatic plant areas exposed to solvents and noise and utility area workers exposed only to noise were analyzed for the standard threshold shift (STS). Despite the low exposures to solvents and a moderate exposure to noise, 45.3% of workers had hearing losses and 29.6% had STS.

Vascular endothelial growth factor in minor salivary glands: effect of ageing.

Morphological and physiological age changes are described in human salivary glands. Vascular endothelial growth factor (VEGF) is neoangiogenic growth factor found in normal salivary glands. Considering the neoangiogenic properties of VEGF and its important function in inflammation, repair and, probably, in oral mucosa homeostasis, the purpose of the present study was to evaluate the effect of ageing on the immunolocalization of VEGF in minor salivary glands. Paraffin-embedded tissue blocks containing normal labial salivary glands were retrieved and classified according to the patients' age in two groups (< 20 and > 40-year-old). The biotin-streptavidin-peroxidase system was used to detect the VEGF antigen. The results demonstrated that the mean level of VEGF immunoreaction in the young group was not statistically different from the old group when compared by the Mann-Whitney U-test (P = 0.54). This may indicate that although salivary flow reduction may develop in old patients, some properties of the salivary glands may not be affected.

Ausência de micorrizas vesículo-arbusculares efetivas em lecythidaceas numa área de floresta primária da amazônia central

Lecythidaceae comprise one of the four most common tree families in the Amazon forest, but there have been few studies of vesicular-arbuscular mycorrhizae in this taxon. In this study roots of 31 species in six genera of Lecythidaceae were collected in a primary forest on an acid oxisol. No vesicular-arbuscular mycorrhizae, as indicated by the presence of vesicles or arbuscules were detected. Only some hyfas were found on some species roots, but not enough for increasing the nutrient absorption from the soil. This indicated that under the edaphic condiction and the time which the samples were collected, these species worked as no mycor-rhizal plants. These informations confirm datas found for other researches, and may be important for exploring more efficiently and by a not predatory way, the species of Lecythidaceae on agroforestry systems in the Amazon.

As Lecythidaceae compreendem uma das quatro famílias de árvores mais abundantes na floresta amazônica, mas foram pouco estudadas no que sc refere à simbiose com fungos micorrízicos dos solos. Foram coletadas raízes de 31 espécies de seis gêneros desta família numa floresta de terra firme da Amazônia Central, próxima a Manaus, sob um latossolo amarelo. Em algumas espécies observou-se uma ausência total de fungos nas raízes, enquanto que em outras, apenas algumas hifas de fungos, mas sem vesículas ou arbúsculos, estruturas que serviriam para confirmar a presença de micorrizas vesículo-arbusculares efetivas nas mesmas. As poucas bifas encontradas não seriam suficientes para aumentar a absorção de nutrientes do solo, indicando que nas condições edáficas e épocas de coletas do presente estudo, as plantas se comportaram como não micorrizicas. Estas informações reforçam dados obtidos por outros autores e podem servir de embasamento para uma exploração mais eficiente e não predatória de espécies desta família em sistemas agroflorestais na Amazônia.

[The Northeast: fertility and recent dynamics of the labor force]. / Nordeste: fecundidade e dinamica recente da forca de trabalho.

PIP: Data from the 1970 and 1980 censuses of Brazil are analyzed to examine the economic growth of the Notheast, changes in the region's population dynamics, and changes in fertility. Consideration is given to the segmentation of the urban labor market, the income of the economically active population, children in the labor force, female education versus fertility, and family income versus female participation in the work force.^ieng