Effects of ion beam on nanoindentation characteristics of glassy polymeric carbon surface

Glassy polymeric carbon (GPC) is a useful material for medical applications due to its chemical inertness and biocompatible characteristics. Mitral and aortic and hydrocephalic valves are examples of GPC prosthetic devices that have been fabricated and commercialized in Brazil. In this work, ion beam was used to improve the mechanical characteristics of GPC surface and therefore to avoid the propagation of microcracks where the cardiac valves are more fragile. A control group of phenolic resin samples heat-treated at 300, 400, 700, 1000, 1500, and 2500 degrees C was characterized by measuring their hardness and Young's reduced elastic modulus with the depth of indentation. The control group was compared to results obtained with samples heat-treated at 700, 1000, and 1500 degrees C and bombarded with energetic ions of silicon, carbon, oxygen, and gold at energies of 5, 6, 8, and 10 MeV, respectively, with fluences between 10x10(13) and 10x10(16) ions/cm(2). GPC nonbombarded samples showed that hardness depends on the heat treatment temperature (HTT), with a maximum hardness for heat treatment at 1000 degrees C. The comparison between the control group and bombarded group also showed that hardness, after bombardment, had a greater increase for samples prepared at 700 degrees C than for samples prepared at higher temperatures. The Young's elastic modulus presents an exponential relationship with depth. The parameters obtained by fitting depend on the HTT and on the ion used in the bombardment more than on energy and fluence. The hardness results show clearly that bombardment can promote carbonization, increase the linkage between the chains of the polymeric material, and promote recombination of broken bonds in lateral groups that are more numerous for samples heat-treated at 700 degrees C. (c) 2004 Elsevier B.V. All rights reserved.

Use of FIA systems for on-line dilution in multielement determination by ICP-MS

A flow-injection (FI) system to match concentrations was used as an auto-diluter in multielement determination by inductively coupled plasma-mass spectrometry (ICP-MS). The flow system comprised loop-based injection or a timed valve that introduced a variable sample volume info a spray chamber through a standard Meinhard nebulizer of an ICP-MS. Routinely analyzed samples such as water, plant, and steel were selected. The accuracy of multielement determination was checked against water standard reference material from the National Institute of Standards and Technology (1643d), plant standard reference material from the National Bureau of Standards (1572 citrus leaves), and steel standard reference material from the National Bureau of Standards (AISI 4340). The measuring system was calibrated with a multielement solution, yielding a linear plot with good precision [relative standard deviation (RSD) < 3%, n = 12]. The results were in agreement at a 95% confidence level with the certified values for the reference materials and also with those obtained by continuous aspiration and by (FI) with a discrete volume. (C) 1999 John Wiley & Sons, Inc.

Demographic of short gut syndrome: Increasing demand is not followed by referral of potential candidates for small bowel transplantation

Background. Despite improvements in small bowel transplantation (SBTx), early referral of patients with irreversible intestinal failure (IF) remains a major obstacle. In this study we evaluated the demand for SBTx among seven surgical pediatric centers located at least 200 km from our center.Methods. From 1997 to 2001, 640 patients have been treated for neonatal diseases, including 248 who underwent a minor or major intestinal resection. Twenty-four patients with major resections presented with short gut syndrome, requiring total parenteral nutrition (TPN). The greatest demand was in postsurgical neonates with necrotizing enterocolitis, gastroschiesis, onphalocoeles, or midgut volvulus, and in three adults with postradiotherapy arteritis (n = 2) and mesenteric vein thromboses (n = 1). The median length of residual bowel after resection was 20 to 30 cm, without an ileocecal valve. Four patients were referred for SBTx evaluation; three died while awaiting a donor; 20 were not referred, among whom 14 died of TPN complications.Results. Approximately 62 children per year require nutritional support for IF, most of whom develop complications related to TPN. Because many patients who are TPN-dependent develop complications, we believe that early referral would reduce mortality.Conclusions. Greater medical awareness about the feasibility of SBTx procedures and earlier referral may improve results and quality of life after transplant.

Anatomic data of the human coronary sinus

The authors studied the formation, tributaries, lenght and the ostium of the coronary sinus, as well as the relationship of the venous walls to the myocardium and to the epicardium. The observations were made out of 143 hearts of subjects of different ages, and it was found that the most frequent display of the coronary sinus valve was a semilunar form (52 adults, 15 youngsters, 2 children, 3 newborn); it was also found valves in a cribiform or septal form. The absence of the valve of coronary sinus was noted in 53 cases (42 adults, 9 youngsters, 2 newborn). The valve of Vieussens was found, in some cases, at the level of the transition between the great cardiac vein and the coronary sinus, as well as others single or double parietal venous valves. The action of the valve of coronary sinus is also discussed by the authors.

Relações pressão-diâmetro e esforço-diâmetro do ventrículo esquerdo em seres humanos. Padronização e análise crítica do método.

PURPOSE--To provide a critical analysis of the fluid filled manometric system and M-mode echocardiography and, by their association, to standardize the determination of left ventricular (LV) pressure-diameter and stress-diameter relationships in humans. MATERIAL AND METHODS--The pressure curve and the LV M-mode image was obtained in 24 patients with cardiopathy. The dynamic characteristics of the fluid-filled system have been studied to define the amplitude, the resonance and the time gap of the pressure curve register. The delay of the pressure curve recording was determined in all cases by comparing pressure curve and echocardiographic aortic valve registers. The values of pressure, diameter, posterior wall thickness and LV meridional stress was calculated at every 0.02s. RESULTS--Preliminary analyses of the fluid-filled manometric system indicated that this system has variable dynamic characteristics. The pressure-diameter and stress-diameter loops obtained were similar to those of the literature. The values of end-systolic stress, percentage of fractional shortening, ejection fraction and circumferential fiber shortening rate of patients with dilated cardiomyopathy (n = 5) were significantly reduced when compared to the values of patients without left ventricular overload (n = 8) and patients with ventricular volume overload. It has been verified, also, that the retard of the pressure curve record introduced by the fluid-filled manometric system does not modify the values of these variables. CONCLUSION--The LV pressure-diameter and stress-diameter relationships obtained by the association of echocardiography and LV manometry showed functional characteristics of the ventricle that could not appear by the use of the echocardiography or by the LV manometry themselves.

Obstrução nasolacrimal congênita - Diagnóstico e tratamento

Patients with congenital nasolacrimal obstruction (CNLO) were evaluated at the Lacrimal Apparatus Service of Botucatu Faculty of Medicine - UNESP from 1990 to 1993. 45 children were seen at this period with CNLO. The diagnosis was confirmed by dacryocystography (DCG). Obstruction was unilateral in 77,7% of the patients; 68,1% at Arlt Sinus and 43,6% had lacrimal sac grade 1. Probing was made in children older than 6 months, under general anaesthesia, after DCG was performed. Cure was greater in children age 6 to 12 months with obstruction at Hasner's Valve and without dilation of lacrimal sac.

Heritability of sting characters in Africanized honeybees

In this paper we proposed to estimate the heritability of seven morphological characters that compose the sting apparatus ofthe Africanized honeybee workers. An experimental design to estimate genetic parameters was based on the method developed by Oldroyd and Moran. This method was modified to eliminate within-colony environmental effects associated with the additive genetic variance. The estimated h2 values ranged from 0.17 ± 0.11 (maximum width of bulb of sting stylet and height of the valve of right lancet) to 0.74 ± 0.30 (length of the lancet).

Coeficientes de perda de carga em valvulas e acessorios no escoamento laminar de fluidos nao-Newtonianos

Friction loss coefficients for laminar flow of xantan gum solutions (concentrations in the range of 0.1-0.5% by weight) through valves and fittings were experimentally determined. The rheological behavior, studied by means of a concentric cylinder rheometer, was pseudoplastic, being well described by the Ostwald-De Waele model with non-linear correlation coefficients (r) between 0.998 and 0.999. In the pressure drop measurements the following fittings were employed: completely open and half way open ball valve, completely open and half way open angle valve, tee used like coupling, tee used like a 90° elbow, short radius 90° elbow and coupling. The results showed that the friction loss coefficients increased with decreasing generalized Reynolds number. The friction loss coefficients could be well adjusted by a potential model, suggested by Kittredge & Rowley (1957) for Newtonian fluids, K f = A(Re g) -B, with correlation coefficients between 0.837 and 0.999.

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.

Echocardiographic Doppler estimation of pulmonary artery pressure in critically ill patients with severe hypoxemia

BACKGROUND: In spontaneously breathing cardiac patients, pulmonary artery pressure (PAP) can be accurately estimated from the transthoracic Doppler study of pulmonary artery and tricuspid regurgitation blood flows. In critically ill patients on mechanical ventilation for acute lung injury, the interposition of gas between the probe and the heart renders the transthoracic approach problematic. This study was aimed at determining whether the transesophageal approach could offer an alternative. METHODS: Fifty-one consecutive sedated and ventilated patients with severe hypoxemia (arterial oxygen tension/fraction of inspired oxygen < 300) were prospectively studied. Mean PAP measured from the pulmonary artery catheter was compared with several indices characterizing pulmonary artery blood flow assessed using transesophageal echocardiography: preejection time, acceleration time, ejection duration, preejection time on ejection duration ratio, and acceleration time on ejection duration ratio. In a subgroup of 20 patients, systolic PAP measured from the pulmonary artery catheter immediately before withdrawal was compared with Doppler study of regurgitation tricuspid flow performed immediately after pulmonary artery catheter withdrawal using either the transthoracic or the transesophageal approach. RESULTS: Weak and clinically irrelevant correlations were found between mean PAP and indices of pulmonary artery flow. A statistically significant and clinically relevant correlation was found between systolic PAP and regurgitation tricuspid flow. In 3 patients (14%), pulmonary artery pressure could not be assessed echocardiographically. CONCLUSIONS: In hypoxemic patients on mechanical ventilation, mean PAP cannot be reliably estimated from indices characterizing pulmonary artery blood flow. Systolic PAP can be estimated from regurgitation tricuspid flow using either transthoracic or transesophageal approach. © 2008 American Society of Anesthesiologists, Inc.

Biotic interaction between spionid polychaetes and bouchardiid brachiopods: Paleoecological, taphonomic and evolutionary implications

Shells of Bouchardia rosea (Brachiopoda, Rhynchonelliformea) are abundant in Late Holocene death assemblages of the Ubatuba Bight, Brazil, SW Atlantic. This genus is also known from multiple localities in the Cenozoic fossil record of South America. A total of 1211 valves of B. rosea, 2086 shells of sympatric bivalve mollusks (14 nearshore localities ranging in depth from 0 to 30 m), 80 shells of Bouchardia zitteli, San Julián Formation, Paleogene, Argentina, and 135 shells of Bouchardia transplatina, Camacho Formation, Neogene, Uruguay were examined for bioerosion traces. All examined bouchardiid shells represent shallow-water, subtropical marine settings. Out of 1211 brachiopod shells of B. rosea, 1201 represent dead individuals. A total of 149 dead specimens displayed polychaete traces (Caulostrepsis). Live polychaetes were found inside Caulostrepsis borings in 10 life-collected brachiopods, indicating a syn-vivo interaction (Caulostrepsis traces in dead shells of B. rosea were always empty). The long and coiled peristomial palps, large chaetae on both sides of the 5th segment, and flanged pygidium found in the polychaetes are characteristic of the polychaete genus Polydora (Spionidae). The fact that 100% of the Caulostrepsis found in living brachiopods were still inhabited by the trace-making spionids, whereas none was found in dead hosts, implies active biotic interaction between the two living organisms rather than colonization of dead brachiopod shells. The absence of blisters, the lack of valve/site stereotypy, and the fact that tubes open only externally are all suggestive of a commensal relationship. These data document a new host group (bouchardiid rhynchonelliform brachiopods) with which spionids can interact (interestingly, spionid-infested sympatric bivalves have not been found in the study area despite extensive sampling). The syn-vivo interaction indicates that substantial bioerosion may occur when the host is alive. Thus, the presence of such bioerosion traces on fossil shells need not imply a prolonged post-mortem exposure of shells on the sea floor. Also, none of the Paleogene and Neogene Bouchardia species included any ichnological evidence for spionid infestation. This indicates that the Spionidae/ Bouchardia association may be geologically young, although the lack of older records may also reflect limited sampling and/or taphonomic biases.

Influence of vegetable oil in the viscosity of biodiesel-a review

Viscosity is a measure fluid resistance to flowing, affecting the fuel spray in the combustion chamber and, by this way, thus the formation of carbon deposits. The analysis of the influence of vegetable oil viscosity in biodiesel seems appropriate, because biodiesel viscosity is a function of vegetable oil. The increase of the fuel viscosity, promoted by biodiesel, has a major impact on the dynamics of jet fuel, increasing its speed and distance of penetration, obtaining therefore an increase in the amount of turbulent movement of the jet and thus an increase in the rate of preparation of the mixture, air-fuel, when adding biodiesel to diesel oil. The negative effect of this higher fuel viscosity is the increase of the wear of the train of gears, cam shaft, and valve push rod of all the injection pumps due to the higher pressure of injection. The viscosity of biodiesel is influenced by the size of its molecule and by the increase of molecule insaturations, is directly related with its origin vegetable oil or fat. This study is a review of the influence of vegetable oils in viscosity of biodiesel. Copyright © 2008 SAE International.

Highlights from the I international symposium of thrombosis and anticoagulation in internal medicine, October 23-25, 2008, Sao Paulo, Brazil

The importance of thrombosis and anticoagulation in clinical practice is rooted firmly in several fundamental constructs that can be applied both broadly and globally. Awareness and the appropriate use of anticoagulant therapy remain the keys to prevention and treatment. However, to assure maximal efficacy and safety, the clinician must, according to the available evidence, choose the right drug, at the right dose, for the right patient, under the right indication, and for the right duration of time. The first International Symposium of Thrombosis and Anticoagulation in Internal Medicine was a scientific program developed by clinicians for clinicians. The primary objective of the meeting was to educate, motivate and inspire internists, cardiologists and hematologists by convening national and international visionaries, thought-leaders and dedicated clinician-scientists in Sao Paulo, Brazil. This article is a focused summary of the symposium proceedings. © Springer Science+Business Media, LLC 2009.

Mau Funcionamento do Sistema de Circulação Extracorpórea: Relato de Caso

Background and objectives: The introduction of extracorporeal circulation in clinical practice was decisive for the development of modern cardiovascular surgery. Addition of new procedures and equipment, however, brings inherent risks and complications. The objective of this report is to describe a malfunction of the oxygenation system and emphasize the importance of the interaction among the medical team members to prevent errors and complications. Case Report: During valve replacement and IVC correction surgery, we observed a darker shade of red in the blood on the exit of the oxygenator. Laboratory tests demonstrated severe acidosis and hypoxemia. The entire system was evaluated, but the cause of the malfunction was not found. Measures to reduce damage were successfully instituted. After the surgery, the whole system underwent technical evaluation. Conclusions: Interaction among the medical team members, early diagnosis, and immediate intervention were fundamental for a favorable outcome. © 2011 Elsevier Editora Ltda.

Simulation of the flow through automatic valves of hermetic compressors by the immersed boundary method approach

The main goal of the present work is to verify the applicability of the Immersed Boundary Method together with the Virtual Physical Model to solve the flow through automatic valves of hermetic compressors. The valve was simplified to a two-dimensional radial diffuser, with diameter ratio of D/d = 1.5, and simulated for a one cycle of opening and closing process with a imposed velocity of 3.0 cm/s for the reed, dimensionless gap between disks in the range of 0.07 < s/d < 0.10, and inlet Reynolds number equal to 1500. The good results obtained showed that the methodology has great potential as project tool for this type of valve systems. © The Authors, 2011.