Silver colloidal nanoparticles: Effect on matrix composition and structure of Candida albicans and Candida glabrata biofilms

Aim: The aim of this study was to assess the effect of different silver nanoparticles (SN) concentrations on the matrix composition and structure of Candida albicans and Candida glabrata biofilms. Methods and Results: Candida biofilms were developed in 6-well microtiter plates during 48 h. After, these biofilms were exposed to 13·5 or 54 μg SN ml-1 for 24 h. Then, extracellular matrices were extracted from biofilms and analysed chemically in terms of proteins, carbohydrates and DNA. To investigate the biofilm structure, scanning electron microscopy (SEM) and epifluorescence microscopy were used. SN interfered with the matrix composition of Candida biofilms tested in terms of protein, carbohydrate and DNA, except for the protein content of C. albicans biofilm. By SEM, Candida biofilms treated with SN revealed structural differences, when compared with the control groups. Further, SN showed a trend of agglomeration within the biofilms. Epifluorescence microscopy images suggest that SN induced damage on cell walls of the Candida isolates tested. Conclusions: In general, irrespective of concentration, SN affected the matrix composition and structure of Candida biofilms and these findings may be related to the mechanisms of biocide action of SN. Significance and Impact of the Study: This study reveals new insights about the behaviour of SN when in contact with Candida biofilms. SN may contribute to the development of therapies to prevent or control Candida infections. © 2012 The Society for Applied Microbiology.

Phosphorus and potassium balance in a corn-soybean rotation under no-till and chiseling

Nutrient use efficiency has become an important issue in agriculture, and crop rotations with deep vigorous rooted cover crops under no till may be an important tool in increasing nutrient conservation in agricultural systems. Ruzigrass (Brachiaria ruziziensis) has a vigorous, deep root system and may be effective in cycling P and K. The balance of P and K in cropping systems with crop rotations using ruzigrass, pearl millet (Pennisetum glaucum) and ruzigrass + castor bean (Ricinus communis), chiseled or not, was calculated down to 0.60 m in the soil profile for 2 years. The cash crops were corn in the first year and soybean in the second year. Crop rotations under no-till increased available P amounts in the soil-plant system from 80 to 100 %, and reduced K losses between 4 and 23 %. The benefits in nutrient balance promoted by crop rotations were higher in the second year and under without chiseling. Plant residues deposited on the soil surface in no-till systems contain considerable nutrient reserve and increase fertilizer use efficiency. However, P release from ruzigrass grown as a sole crop is not synchronized with soybean uptake rate, which may result in decreased yields. © 2013 Springer Science+Business Media Dordrecht.

Tissue engineering: Using collagen type i matrix for bone healing of bone defects

Among the many tissues in the human body, bone has been considered as a powerful marker for regeneration and its formation serves as a prototype model for tissue engineering based on morphogenesis. Therefore, collagen type I is one of the most useful biomaterials used in tissue engineering as extracellular matrix components capable to promote bone healing. The literature reveals excellent biocompatibility and safety due to its biological characteristics, such as biodegradability and weak antigenicity, making collagen type I the primary resource in medical applications. Thus, it was also used for tissue engineering including skin replacement, bone substitutes, and artificial blood vessels and valves. The authors describe the treatment of an abscessed apical periodontal cyst and show good outcomes of bone healing, using tissue engineering, as collagen type I matrix. © 2013 by Mutaz B. Habal, MD.

A finite element approach for predicting the ultimate rotation capacity of RC beams

This paper presents a numerical approach to model the complex failure mechanisms that define the ultimate rotational capacity of reinforced concrete beams. The behavior in tension and compression is described by a constitutive damage model derived from a combination of two specific damage models [1]. The nonlinear behavior of the compressed region is treated by the compressive damage model based on the Drucker-Prager criterion written in terms of the effective stresses. The tensile damage model employs a failure criterion based on the strain energy associated with the positive part the effective stress tensor. This model is used to describe the behavior of very thin bands of strain localization, which are embedded in finite elements to represent multiple cracks that occur in the tensioned region [2]. The softening law establishes dissipation energy compatible with the fracture energy of the concrete. The reinforcing steel bars are modeled by truss elements with elastic-perfect plastic behavior. It is shown that the resulting approach is able to predict the different stages of the collapse mechanism of beams with distinct sizes and reinforcement ratios. The tensile damage model and the finite element embedded crack approach are able to describe the stiffness reduction due to concrete cracking in the tensile zone. The truss elements are able to reproduce the effects of steel yielding and, finally, the compressive damage model is able to describe the non-linear behavior of the compressive zone until the complete collapse of the beam due to crushing of concrete. The proposed approach is able to predict well the plastic rotation capacity of tested beams [3], including size-scale effects.

Matrix effect on butyltin analysis of sediments and fish tissues by GC-PFPD

Butyltin (BTs) quantification in environmental matrices can be affected by interfering species found primarily in complex matrices,such as sediment and biota tissues. This study investigated matrix effects in analytical procedures for butyltin (TBT,DBT and MBT) quantification and speciation in sediments and in two fish tissues (gill and liver) by gas chromatography with pulsed flame photometric detection (GC-PFPD) analysis. Unlike sediment samples,tissues exhibited a significant matrix effect,thus,the quantification should be made by curve over matrix to avoid quantification errors and loss of analytical accuracy. © 2013 Sociedade Brasileira de Química.

Dynamics of rotation of super-Earths

We numerically investigate the dynamics of rotation of several close-in terrestrial exoplanet candidates. In our model, the rotation of the planet is disturbed by the torque of the central star due to the asymmetric equilibrium figure of the planet. We model the shape of the planet by a Jeans spheroid. We use surfaces of section and spectral analysis to explore numerically the rotation phase space of the systems adopting different sets of parameters and initial conditions close to the main spin-orbit resonant states. One of the parameters, the orbital eccentricity, is critically discussed here within the domain of validity of orbital circularization timescales given by tidal models. We show that, depending on some parameters of the system like the radius and mass of the planet, eccentricity etc., the rotation can be strongly perturbed and a chaotic layer around the synchronous state may occupy a significant region of the phase space. 55 Cnc e is an example. © 2013 Springer Science+Business Media Dordrecht.

Airway space changes after maxillomandibular counterclockwise rotation and mandibular advancement with TMJ Concepts® total joint prostheses: Three-dimensional assessment

This study focused on three-dimensional (3D) airway space changes and stability following simultaneous maxillomandibular counterclockwise rotation, mandibular advancement, and temporomandibular joint (TMJ) reconstruction with custom-made total joint prostheses (TMJ Concepts®). Cone beam computed tomography (CBCT) scans of 30 consecutive female patients with irreversibly compromised TMJs were obtained at the following intervals: T1, presurgery; T2, immediately after surgery; and T3, at least 6 months after surgery. The CBCT volumetric datasets were analysed with Dolphin Imaging ® software to evaluate surgical and postsurgical changes to oropharyngeal airway parameters. The average changes in airway surface area (SA), volume (VOL), and minimum axial area (MAA) were, 179.50 mm2, 6302.60 mm3, and 92.23 mm2, respectively, at the longest follow-up (T3 - T1) (P ≤ 0.001). Significant correlations between the amount of mandibular advancement and counterclockwise rotation of the occlusal plane and 3D airway changes were also found (P ≤ 0.01). The results of this investigation showed a significant immediate 3D airway space increase after maxillomandibular counterclockwise rotation and mandibular advancement with TMJ Concepts total joint prostheses, which remained stable over the follow-up period. © 2013 International Association of Oral and Maxillofacial Surgeons.

A single chart with supplementary runs rules for monitoring the mean vector and the covariance matrix of multivariate processes

The MRMAX chart is a single chart based on the standardized sample means and sample ranges for monitoring the mean vector and the covariance matrix of multivariate processes. User's familiarity with the computation of these statistics is a point in favor of the MRMAX chart. As a single chart, the recently proposed MRMAX chart is very appropriate for supplementary runs rules. In this article, we compare the supplemented MRMAX chart and the synthetic MRMAX chart with the standard MRMAX chart. The supplementary and the synthetic runs rules enhance the performance of the MRMAX chart. © 2013 Elsevier Ltd.

Soil organic matter and physical attributes affected by crop rotation under no-till

Growing cover crops in systems under no tillage affects different pools of soil organic matter, and eventually soil physical attributes are modified. The objective of this study was to evaluate changes in soil organic matter and their relationship with soil physical attributes as affected by plant species grown in rotation with soybean [Glycine max (L.) Merr.] under no-till for 3 yr. Crop rotations included grain sorghum [Sorghum bicolor (L.) Moench], ruzigrass [Urochloa ruziziensis (R. Germ, and CM. Evard) Crins] and sorghum mixed with ruzigrass, all grown in fall/winter, followed by pearl millet [Pennisetum americanum (L.) Leeke], sunn hemp (Crotalaria juncea L.) and sorghum-sudangrass [S. bicolor × S. sudanense (Piper) Stapf] grown during the spring, plus a fallow check plot. Soybean was grown as the summer crop. Millet and sorghum-sudangrass cropped in spring showed higher root and shoot production as spring cropping. In fall/winter, sorghum mixed with ruzigrass yielded higher phytomass compared with sole cropping. Soil physical attributes and organic matter fractioning were positively affected by cropping millet and sorghum-sudangrass whereas intermediate effects were observed after sunn hemp. Maintaining fallow in spring had negative effects on soil organic matter and physical properties. Ruzigrass and sorghum mixed with ruzigrass cropped in fall/winter resulted in better soil quality. Spring cover crops were more efficient in changing soil bulk density, porosity, and aggregates down to 0 to 10 cm; on the other hand, fall/winter cropping showed significant effects on bulk density in the uppermost soil layer. Total C levels in soil were increased after a 3-yr rotation period due to poor initial physical conditions. Fractions of particulate organic C, microbial C, and C in macroaggregates were the most affected by crop rotations, and showed high relation with improved soil physical attributes (porosity, density, and aggregates larger than 2 mm). © Soil Science Society of America, All rights reserved.

Elevated hyaluronan and extracellular matrix metalloproteinase inducer levels in women with preeclampsia

Purpose: Preeclampsia (PE) is a specific syndrome of pregnancy clinically identified by hypertension and proteinuria from the 20th week of gestation associated with a systemic inflammatory response and oxidative stress. While pro-inflammatory cytokines have been extensively studied in PE, other factors in the circulation that also influence the magnitude of inflammation have received much less attention. The present study compared serum concentrations of five immune-regulatory compounds in normotensive pregnant women and in women with gestational hypertension (GH) or PE. Methods: Sixty women with PE, 53 with GH and 40 normotensive women paired by gestational age were evaluated. Sera were evaluated for concentrations of extracellular matrix metalloproteinase inducer (EMMPRIN), hyaluronan, gelsolin, visfatin and histone 2B by ELISA. Differences between groups were analyzed by nonparametric tests, with a significance level of 5 %. Results: Increased levels of EMMPRIN and hyaluronan were present in preeclamptic women as compared to the GH and normotensive groups. There was no difference between groups in gelsolin, visfatin or histone 2B. Conclusion: Increased release of EMMPRIN and hyaluronan may contribute to an elevated pro-inflammatory response and tissue damage in women with PE. © 2013 Springer-Verlag Berlin Heidelberg.

Platelet-Rich Plasma And Chronic Wounds: Remaining Fibronectin May Influence Matrix Remodeling And Regeneration Success

Background: Platelet-rich plasma has been largely used as a therapeutic option for the treatment of chronic wounds of different etiologies. The enhanced regeneration observed after the use of platelet-rich plasma has been systematically attributed to the growth factors that are present inside platelets' granules. Aim: We hypothesize that the remaining plasma and platelet-bound fibronectin may act as a further bioactive protein in platelet-rich plasma preparations. Methods: Recent reports were analyzed and presented as direct evidences of this hypotheses. Results: Fibronectin may directly influence the extracellular matrix remodeling during wound repair. This effect is probably through matrix metalloproteinase expression, thus exerting an extra effect on chronic wound regeneration. Conclusions: Physicians should be well aware of the possible fibronectin-induced effects in their future endeavors with PRP in chronic wound treatment. © 2013 International Society for Cellular Therapy.

Matrix Effects on Water Analysis for Alkylphenols Using Solid Phase Extraction Gas Chromatography-Mass Spectrometry

Gas chromatography with mass spectrometry is frequently used for the quantification of many classes of substances, including alkylphenols. Alkylphenol polyethoxylates are nonionic surfactants used in a wide variety of industrial and consumer applications. Alkylphenol polyethoxylates can degrade to alkylphenols, which are endocrine disruptors. In analytical validation procedures, the most common parameters studied are the detection and quantification limits, linearity, and recovery; however, the matrix effects are sometimes neglected. Although some investigators have evaluated matrix effects, there is no consensus on how to evaluate them during method validation. In this study, the matrix effects of alkylphenol polyethoxylates (nonylphenol monoethoxylate, nonylphenol diethoxylate, octylphenol monoethoxylate, octylphenol diethoxylate) and alkylphenols (nonylphenol and octylphenol) were studied using solid phase extraction and gas chromatography-mass spectrometry analysis. For alkylphenol polyethoxylates, the matrix effects ranged from 16 to 4692%, whereas for alkylphenols (nonylphenol and octylphenol), the effects were insignificant. Therefore, constructing an analytical curve in the matrix for alkylphenol polyethoxylates is essential. © 2013 Copyright Taylor and Francis Group, LLC.

Processo de reparo ósseo de cavidades cirúrgicas preenchidas ou não com osso autógeno e recobertas por membrana de matriz óssea homógena em diabéticos: análise histomorfométrica em tíbia de ratos

Pós-graduação em Odontologia - FOA

Em busca do espaço perdido em Matrix: do terrorismo teórico à violência simbólica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Systemic analysis of the health sector through the input-output matrix, 2000-2005

This article provides a systemic analysis of the health sector in Brazil, based on a study of its productive structure and its interactions with the other sectors of the economy. The article draws on unpublished data on the National Health Accounts provided by the Brazilian Geographical and Statistical Institute (ibge); and it proposes a methodology for harmonizing the System of National Accounts (input-output matrix) with the Health Satellite Accounts for 2000 and 2005. This sheds light on the relations that exist between the health sector and the other sectors the economy, through input-output indicators.