Numerical and experimental analysis of natural convection in a cavity with flush mounted heat sources on a side wall

This work considers a problem of interest in several technological applications such as the thermal control of electronic equipment. It is also important to study the heat transfer performance of these components under off-normal conditions, such as during failure of cooling fans. The effect of natural convection on the flow and heat transfer in a cavity with two flush mounted heat sources on the left vertical wall, simulating electronic components, is studied numerically and experimentally. The influence of the power distribution, spacing between the heat sources and cavity aspect ratio have been investigated. An analysis of the average Nusselt number of the two heat sources was performed to investigate the behavior of the heat transfer coefficients. The results obtained numerically and experimentally, after an error analysis, showed a good agreement.

Plant Cell Wall Research Related to Evolution and Chemical Defenses

The plant cell wall is composed mainly of polysaccharides some constituted of repeating units of a single sugar, as cellulose or by two or more sugars grouped in repeating oligosaccharide blocks as the galactomannans and xyloglucans. Variations in composition and fine structure of these cell wall polysaccharides have been used as taxonomic markers and in the comprehension of the evolutive process, particularly in the Leguminosae. Partial hydrolysis of these compounds give rise to oligomers, some of which are capable of eliciting the synthesis of defensive substances in plants named phytoalexins. Species which differ in respect to phytoalexin liberation also differ in cell wall composition, particularly in the pectic fraction of the wall. Pectinases (mainly endopolygalacturonases) present in fungi, have been shown to hydrolyze plant cell walls yielding phytoalexin-eliciting oligosaccharides which differ in composition and in eliciting capacity in different species. These differences can be associated with the capacity of a given species to produce phytoalexins. On the other hand, the phytoalexin induction in plants is being used as a method of producing novel bioactive secondary metabolites.

Reduction of diameter of the left ventricle of dogs by plication of the left ventricular free wall

Objective - To determine effects of reducing the diameter of the left ventricle of dogs by plication of the left ventricular free wall. Animals - 8 healthy adult mixed-breed dogs. Procedure - Left lateral thoracotomy and a T-shaped pericardiotomy were performed. The free wall of the left ventricle was imbricated with 3 interrupted transfixing sutures applied in a horizontal mattress pattern, using 3-0 polypropylene suture assembled on a straight cutting needle. Surgeons were careful to avoid the coronary vessels. Echocardiography was performed 24 hours before and 48 hours after surgery. Electrocardiography was performed before and 1, 2, 7, 15, 21, 30, and 60 days after surgery. Results - Echocardiographic measurements revealed that the diameter of the left ventricle was reduced by a mean of 23.5%. Electrocardiography revealed ventricular premature complexes 24 hours after surgery that regressed without treatment during the first week after surgery. Conclusions and Clinical Relevance - Plication of the left ventricular free wall of dogs can reduce end-diastolic and end-systolic dimensions of the left ventricle. The technique is simple and does not require cardiopulmonary bypass. According to Laplace's law, the reduction of cardiac diameter leads to reduction on free-wall tension and may improve left ventricular function in dilatated hearts. Thus, additional studies involving dogs with dilated cardiomyopathy should be conducted.

Plication of the free wall of the left ventricle in dogs with doxorubicin-induced cardiomyopathy

Objective - To evaluate plication of the free wall of the left ventricle, which reduces the left ventricular area and volume, as a method to improve the left ventricular systolic function without cardiopulmonary bypass. Animals - 8 mixed-breed adult dogs. Procedure - Dilated cardiomyopathy (DCM) was induced in each dog by administration of doxorubicin (30 mg/m2, IV, q 21 d for 168 days). Two dogs died during induction of cardiomyopathy. Plication surgery was performed in 4 dogs. Two dogs did not ondergo to surgery (control group). Values for cardiac output (CO), 2-dimensional and M-mode echocardiography, arterial blood pressure, electrocardiography, blood cell counts, and serum biochemical analyses were recorded after induction of DCM (baseline) and 1, 2, 7, 15, 21, 30, 60, 90, 120, 150, and 180 days after plication surgery. Ambulatory ECG (Holter) recordings were conducted for 24 hours on the day of surgery. Results - 1 dog died after plication surgery. The remaining dogs undergoing ventricular plication had a significant improvement in CO, ejection fraction, and fractional shortening and reductions of left ventricular area and volume after surgery. Electrocardiographic and Holter recordings revealed premature ventricular complexes, which resolved without treatment during the first week after surgery. Clinical condition of the control dogs declined, and these 2 dogs died approximately 40 days after induction of cardiomyopathy. Conclusions and Clinical Relevance - Plication of the free wall of the left ventricle improved left ventricular systolic function in dogs with doxorubicin-induced cardiomyopathy. Additional studies are needed to evaluate its application in dogs with naturally developing DCM.

Effects of copper vapor laser radiation on the root canal wall of human teeth: A scanning electron microscope study

Objective: The aim of this study is to analyze the effects of copper vapor laser radiation on the radicular wall of human teeth. Materials and Methods: Immediately after the crowns of 10 human uniradicular teeth were cut along the cement-enamel junction, a chemical-surgical preparation of the radicular canals was completed. Then the roots were longitudinally sectioned to allow for irradiation of the surfaces of the dentin walls of the root canals. The hemi-roots were separated into two groups: one (control) with five hemi-roots that were not irradiated, and another (experimental) with 15 hemi-roots divided into three subgroups that were submitted to the following exposure times: 0.02,0.05, and 0.1 s. A copper vapor laser (510.6 nm) with a total average power of 6.5 W in green emission, frequency of 16.000 Hz, and pulse duration of 30 ns was used. Results: The results obtained by scanning electron microscope analysis showed the appearance of a cavity in the region of laser beam impact, with melting, recrystallization, and cracking on the edges of the dentin of the cavity due to heat diffusion. Conclusions: We determined that the copper vapor laser produces significant morphologic changes in the radicular wall of human teeth when using the parameters in this study. However, further research should be done to establish parameters that are compatible with dental structure in order to eliminate thermal damages. © Mary Ann Liebert, Inc.

Novas espécies de Staurogyne Wall. (Acanthaceae) para o Brasil

The genus Staurogyne Wall. comprises about 140 tropical species, and in the Neotropics 28 species are recognized, especially found in preserved forested areas. A recent revision of the genus for the Americas revealed four new species in Brazil, which are here described. The new taxa are known from Goiás, Minas Gerais, Espírito Santo, São Paulo, Rio de Janeiro, Paraná and Santa Catarina States, three of them occurring in the Atlantic Rain Forest, and one in the gallery forests of the cerrado domain.

Anomalia congênita em vasos da base do coração de um potro

Congenital anomalies of heart and large vessels are among more common found in animals, however rare in horses. This survey describes a cardiac anomaly that presents confluence between aorta wall and lung trunk, ramification of caudal cava vein in left atrium with presence of valve and consequently erroneous position of heart in thoracic cavity of one foal found dead after birth. The diagnostic was carried out for macroscopic finds association during the necropsy and histopathologic exams carried out at School of Veterinary Medicine - Unesp Araçatuba.

Variabilidade genética na porção codificadora para a proteína capsidial do Lettuce big-vein associated virus e Mirafiori lettuce big-vein virus provenientes de alface no Brasil

Lettuce big vein associated virus (LBVaV) and Mirafiori lettuce big vein virus (MLBVV) have been found in mixed infection in Brazil causing the lettuce big vein disease. Analysis of part of the coat protein (CP) gene of Brazilian isolates of LBVaV collected from lettuce, showed at least 93% amino acid sequence identity with other LBVaV isolates. Genetic diversity among MLBVV CP sequences was higher when compared to LBVaV CP sequences, with amino acid sequence identity ranging between 91% to 100%. Brazilian isolates of MLBVV belong to subgroup A, with one RsaI restriction site on the coat protein gene. There is no indication for a possible geografical origin for the Brazilian isolates of LBVaV and MLBVV.

The possible involvement of hyperpolarizing mechanisms in histamine-induced relaxation of the rat portal vein

The present study evaluated the effects of histamine 10 -2 M on longitudinal preparations of rat portal vein. It was observed that histamine 10 -2 M induced relaxation of rat portal vein preparations pre-contracted with phenylephrine 10 -4 M. On the other hand, no pharmacological effects were observed in preparations not pre-contracted. The observed histamine-induced relaxing effect was absent in preparations pre-contracted with KCl (120 mM) or in the presence of depolarizing nutritive solution. However, the histamine-induced relaxation was still present in the endothelium-removed preparations. The histamine-induced relaxation also was not prevented by astemizole (10 -6 M, 10 -5 M and 10 -4 M), cimetidine (10 -5 M, 10 -4 M and 10 -3 M) or thioperamide (10 -6 M, 10 -5 M and 10 -4 M), selective antagonists H 1, H 2 and H 3, respectively. The presence of L-NAME 10 -4 M or L-NAME 10 -4 M plus indomethacin 10 -5 M also did not prevent the histamine-induced relaxation observed in rat portal vein. Thus, the histamine-induced relaxation observed in rat portal vein appears to involve a non-endothelial hyperpolarizing mechanism independent of H 1, H 2 and H 3 receptors.

Tridimensional modeling of the cardiac wall

The advance in the graphic computer's techniques and computer's capacity of processing made possible applications like the human anatomic structures modeling, in order to investigate diseases, surgical planning or even provide images for training of Computer Aided Diagnosis (CAD). On this context, this work exhibits an anatomical model of cardiac structures represented in a tridimensional environment. The model was represented with geometrical elements and has anatomical details, as the different tunics that compose the cardiac wall and measures that preserves the characteristics found on real structures. The validation of the anatomical model was made through quantitative comparations with real structures measures, available on specialized literature. The results obtained, evaluated by two specialists, are compatible with real anatomies, respecting the anatomical particularities. This degree of representation will allow the verification of the influence of radiological parameters, morphometric peculiarities and stage of the cardiac diseases on the quality of the images, as well as on the performance of the CAD. © 2010 IEEE.

Avaliação morfométrica, realizada pelo exame ultrassonográfico, da veia porta, veia cava caudal e aorta abdominal em cães saudáveis de diferentes pesos corpóreos

The diameters and areas of portal vein, caudal vena cava and abdominal aorta are useful measurements in dogs. These values can be easily measured by ultrasonographic exam, and variations of normality can be an important indicator of hepatic or extra-hepatic alterations. This study aimed to measure the diameter and areas of portal vein, caudal vena cava and abdominal aorta in healthy dogs, with normal corporal score, divided in groups according to the body weight, and assess whether the data are influenced by animal weight. Thirty dogs were examined and divided into three groups (Group A: ≤ 10 kg Group B: from 10.1 to 20.0 kg; Group C: ≥ 20.1 kg). To measure the diameters and areas of portal vein, caudal vena cava and abdominal aorta, the animal was kept in left lateral decubitus position and the transducer was placed on the right lateral abdominal wall, at approximately the 10 th or 11 th intercostal space, in the porta hepatis region. The diameters and areas of the portal vein, caudal vena cava and abdominal aorta were significantly lower for dogs in Group A with respect to other groups and the dogs from Groups B and C had similar results with each other. The diameters and areas of the portal vein, caudal vena cava and abdominal aorta may vary with the animal size, and reference values must be specific for small, medium and large dogs.

Tomographic index as auxiliary criteria for surgery indication in fracture dislocation of acetabulum posterior wall

There are situations which the tomographic exam is done on the affected hip or situations where the contralateral hip presents abnormalities that make it impossible to compare. In this study we aimed to evaluate a tomographic index that does not require comparison between the both hips. Twenty two patients with unilateral acetabular fracture dislocation with fracture of posterior wall were studied. We established the relationship between the remaining posterior wall and the femoral head diameter (head/wall index-H/W index). We evaluated 45 two-dimensional computed tomography scan in normal hips and established the H/W index. In 45 normal hips we simulated a posterior wall fracture with involvement of 25% and 30% of the posterior wall and calculated the H/W index. We divided into five groups with five different H/W index (fractured group with non surgical treatment; fractured group; normal group; normal group with simulated fracture of 25% and; 30% of the posterior wall). 2.4 was the lowest limit of confidence interval of the group with 25% of the posterior wall fracture. When we analyzed the confidence interval of the 30% fracture group the upper limit of the confidence interval was 2.7, close to the lower limit of the surgical group that was 2.9. Thus, we suggest the 2.4 the H/W index limit as an auxiliary criteria to indicate whether or not to operate. H/W index is helpful to decide whether or not surgery indication in the fracture dislocation of the posterior wall of the acetabulum. © 2012 Fujiki et al.; licensee BioMed Central Ltd.

Effects of three restorative techniques in the bond strength and nanoleakage at gingival wall of Class II restorations subjected to simulated aging

Objective: To evaluate the effects of simulated aging in bond strength and nanoleakage of class II restorations using three different restorative techniques. Materials and methods: Class II preparations (n = 12) were restored using: FS - composite resin Filtek Supreme Plus (3M/ESPE); RMGIC + FS - resin-modified glass ionomer cement Vitrebond Plus (3M/ESPE) + FS; and FFS + FS - flowable composite resin Filtek Supreme Plus Flowable (3M ESPE) + FS. The teeth were assigned into two groups: Control and Simulated Aging - Thermal/Mechanical cycling (3,000 cycles, 20-80 °C/500,000 cycles, 50 N). From each tooth, two slabs were assessed to microtensile bond strength test (μTBS) (MPa), and two slabs were prepared for nanoleakage assessment, calculated as penetration along the restoration margin considering the penetration length (%) and as the area of silver nitrate particle deposition (μm2). Data were analyzed by two-way analysis of variance (ANOVA) followed by Tukey's post hoc test (p < 0. 05). Results: FS presented the highest μTBS to dentin (22. 39 ± 7. 55 MPa) after simulated aging, while the presence of flowable resin significantly decreased μTBS (14. 53 ± 11. 65 MPa) when compared to no aging condition. Both control and aging groups of RMGIC + FS presented the highest values of silver nitrate penetration (89. 90 ± 16. 31 % and 97. 14 ± 5. 76 %) and deposition area (33. 05 ± 12. 49 and 28. 08 ± 9. 76 μm2). Nanoleakage was not affected by simulated aging. Conclusions: FS presented higher bond strength and lower nanoleakage and was not affected by simulated aging. Use of flowable resin compromised the bond strength after simulated aging. Clinical relevance: The use of an intermediate layer did not improve the dentin bond strength neither reduced nanoleakage at the gingival margins of class II restorations under simulated aging conditions. © 2012 Springer-Verlag.

One-dimensional Fermi accelerator model with moving wall described by a nonlinear van der Pol oscillator

A modification of the one-dimensional Fermi accelerator model is considered in this work. The dynamics of a classical particle of mass m, confined to bounce elastically between two rigid walls where one is described by a nonlinear van der Pol type oscillator while the other one is fixed, working as a reinjection mechanism of the particle for a next collision, is carefully made by the use of a two-dimensional nonlinear mapping. Two cases are considered: (i) the situation where the particle has mass negligible as compared to the mass of the moving wall and does not affect the motion of it; and (ii) the case where collisions of the particle do affect the movement of the moving wall. For case (i) the phase space is of mixed type leading us to observe a scaling of the average velocity as a function of the parameter (χ) controlling the nonlinearity of the moving wall. For large χ, a diffusion on the velocity is observed leading to the conclusion that Fermi acceleration is taking place. On the other hand, for case (ii), the motion of the moving wall is affected by collisions with the particle. However, due to the properties of the van der Pol oscillator, the moving wall relaxes again to a limit cycle. Such kind of motion absorbs part of the energy of the particle leading to a suppression of the unlimited energy gain as observed in case (i). The phase space shows a set of attractors of different periods whose basin of attraction has a complicated organization. © 2013 American Physical Society.

An anisotropic linear elastic boundary element formulation for masonry wall analysis

This work presents an application of a Boundary Element Method (BEM) formulation for anisotropic body analysis using isotropic fundamental solution. The anisotropy is considered by expressing a residual elastic tensor as the difference of the anisotropic and isotropic elastic tensors. Internal variables and cell discretization of the domain are considered. Masonry is a composite material consisting of bricks (masonry units), mortar and the bond between them and it is necessary to take account of anisotropy in this type of structure. The paper presents the formulation, the elastic tensor of the anisotropic medium properties and the algebraic procedure. Two examples are shown to validate the formulation and good agreement was obtained when comparing analytical and numerical results. Two further examples in which masonry walls were simulated, are used to demonstrate that the presented formulation shows close agreement between BE numerical results and different Finite Element (FE) models. © 2012 Elsevier Ltd.