Medical applications of shape memory alloys

Shape memory alloys (SMA) are materials that have the ability to return to a former shape when subjected to an appropriate thermomechanical procedure. Pseudoelastic and shape memory effects are some of the behaviors presented by these alloys. The unique properties concerning these alloys have encouraged many investigators to look for applications of SMA in different fields of human knowledge. The purpose of this review article is to present a brief discussion of the thermomechanical behavior of SMA and to describe their most promising applications in the biomedical area. These include cardiovascular and orthopedic uses, and surgical instruments.

Applicability of the Appropriate use Criteria for Myocardial Perfusion Scintigraphy

Background: Appropriateness Criteria for nuclear imaging exams were created by American College of Cardiology (ACC) e American Society of Nuclear Cardiology (ASNC) to allow the rational use of tests. Little is known whether these criteria have been followed in clinical practice. Objective: To evaluate whether the medical applications of myocardial perfusion scintigraphy (MPS) in a private nuclear medicine service of a tertiary cardiology hospital were suitable to the criteria of indications proposed by the American medical societies in 2005 and 2009 and compare the level of indication of both. Methods: We included records of 383 patients that underwent MPS, November 2008 up to February 2009. Demographic characteristics, patient's origin, coronary risk factors, time of medical graduation and appropriateness criteria of medical applications were studied. The criteria were evaluated by two independent physicians and, in doubtful cases, defined by a medical expert in MPS. Results: Mean age was 65 ± 12 years. Of the 367 records reviewed, 236 (64.3%) studies were performed in men and 75 (20.4%) were internee. To ACC 2005, 255 (69.5%) were considered appropriate indication and 13 (3.5%) inappropriate. With ACC 2009, 249 (67.8%) were considered appropriate indications and 13 (5.2%) inappropriate. Conclusions: We observed a high rate of adequacy of medical indications for MPS. Compared to the 2005 version, 2009 did not change the results.

Terras raras: aplicações industriais e biológicas

The history of the rare earths is rich in innovation and these elements have been the object of study of a number of scientists. Rare earths are used practically in almost all aspects of life and these applications are due to their outstanding properties, mainly spectroscopic and magnetic. In industry, the applications of rare earths are many, such as in catalysis, phosphors, magnetism, glass and lasers. In biological systems, rare earths are used, for example, as luminescent probes in the investigation of binding sites in proteins, labels in immunoassays and in noninvasive tests.

Uso da RMN como um sensor online em processos industriais

Nuclear magnetic resonance (NMR) is one of the most versatile analytical techniques for chemical, biochemical and medical applications. Despite this great success, NMR is seldom used as a tool in industrial applications. The first application of NMR in flowing samples was published in 1951. However, only in the last ten years Flow NMR has gained momentum and new and potential applications have been proposed. In this review we present the historical evolution of flow or online NMR spectroscopy and imaging, and current developments for use in the automation of industrial processes.

Characterization and oxygen binding properties of des-Arg human hemoglobin

The role of chloride in the stabilization of the deoxy conformation of hemoglobin (Hb), the low oxygen affinity state, has been studied in order to identify the nature of this binding. Previous studies have shown that arginines 141α could be involved in the binding of this ion to the protein. Thus, des-Arg Hb, human hemoglobin modified by removal of the α-chain C-terminal residue Arg141α, is a possible model for studies of these interactions. The loss of Arg141α and all the salt bridges in which it participates is associated with subtle structural perturbations of the α-chains, which include an increase in the conformational flexibility and further shift to the oxy state, increasing oxygen affinity. Thus, this Hb has been the target of many studies of structural and functional behavior along with medical applications. In the present study, we describe the biochemical characterization of des-Arg Hb by electrophoresis, high-performance liquid chromatography and mass spectroscopy. The effects of chloride binding on the oxygen affinity and on the cooperativity to des-Arg Hb and to native human hemoglobin, HbA, were measured and compared. We confirm that des-Arg Hb presents high oxygen affinity and low cooperativity in the presence of bound chloride and show that the binding of chloride to des-Arg does not change its functional characteristics as observed with HbA. These results indicate that Arg141α may be involved in the chloride effect on Hb oxygenation. Moreover, they show that these residues contribute to lower Hb oxygen affinity to a level compatible with its biological function.

Epidemiology and Anthropology: an integrated approach dealing with bio-socio-cultural aspects as strategy for the control of endemic diseases

The control of endemic diseases has not attained the desired level of effectiveness in spite of the use of modern efficient thecnologies. The classic interventionist approach for the control of schistosomiasis is centered on systemic control of the snail hosts combined to large scale medical treatment and is usually carried out without social preocupation due to the assisted communities. It is easy to understand the interest and the ethical compromise of public health research while producing studies in which the biological and social determinants as well as the cultural components should be considered and also encompass the historical dimensions and symbolic representations. In face of the recent political decision in favor of decentralizations of health administration to municipal level, we suggest, in the present paper, an integrated approach for the epidemiological diagnosis of an endemic situation at local level. Theoretical and methodological aspects from both, epidemiology and anthropology are discussed. Epidemiological methods can be used to detect the dependent variables (those related to the human infection) and the independent variables (demographic, economic, sanitary and social). Another methodological approach of anthropological /etnographic nature can be conducted in order to make an articulation of the knowledge on the various dimensions or determinant levels of the disease. Mutual comprehension, between researchers and the people under investigation, on the dynamic transmission process would be relevant for a joint construction, at local level, of programmed actions for the control of endemic diseases. This would extend reflections on the health/disease process as a whole.

Aplicações de QCM, EIS e SPR na investigação de superfícies e interfaces para o desenvolvimento de (bio)sensores

The use of the quartz crystal microbalance process, electrochemical impedance spectroscopy and surface plasmon resonance for characterizing thin films and monitoring interfaces is presented. The theorical aspects of QCM, EIS and SPR are introduced and the main application areas are outlined. Future prospects of the combined applications of QCM, EIS and SPR methods in the studies of interfacial processes at surfaces are also discussed.

Techniques of radioautography for medical and biological research

Standard techniques for radioautography used in biological and medical research can be classified into three categories, i.e., macroscopic radioautography, light microscopic radioautography and electron microscopic radioautography. The routine techniques used in these three procedures are described. With regard to macroscopic radioautography, whole body radioautography is a standard technique which employs freezing and cryosectioning and can demonstrate organ distributions of both soluble and insoluble compounds. In contrast, in light and electron microscopic radioautography, soluble and insoluble techniques are separated. In order to demonstrate insoluble labeled compounds, conventional chemical fixations such as formalin for light microscopy or buffered glutaraldehyde and osmium tetroxide for both light and electron microscopy followed by dehydration, embedding and wet-mounting applications of radioautographic emulsions can be used. For the demonstration of soluble labeled compounds, however, cryotechniques such as cryofixation, cryosectioning, freeze-drying, freeze-substitution followed by dry-sectioning and dry-mounting radioautography should be employed both for light and electron microscopy. The outlines of these techniques, which should be utilized in various fields of biological and medical research, are described in detail

Measuring higher order optical aberrations of the human eye: techniques and applications

In the present paper we discuss the development of "wave-front", an instrument for determining the lower and higher optical aberrations of the human eye. We also discuss the advantages that such instrumentation and techniques might bring to the ophthalmology professional of the 21st century. By shining a small light spot on the retina of subjects and observing the light that is reflected back from within the eye, we are able to quantitatively determine the amount of lower order aberrations (astigmatism, myopia, hyperopia) and higher order aberrations (coma, spherical aberration, etc.). We have measured artificial eyes with calibrated ametropia ranging from +5 to -5 D, with and without 2 D astigmatism with axis at 45º and 90º. We used a device known as the Hartmann-Shack (HS) sensor, originally developed for measuring the optical aberrations of optical instruments and general refracting surfaces in astronomical telescopes. The HS sensor sends information to a computer software for decomposition of wave-front aberrations into a set of Zernike polynomials. These polynomials have special mathematical properties and are more suitable in this case than the traditional Seidel polynomials. We have demonstrated that this technique is more precise than conventional autorefraction, with a root mean square error (RMSE) of less than 0.1 µm for a 4-mm diameter pupil. In terms of dioptric power this represents an RMSE error of less than 0.04 D and 5º for the axis. This precision is sufficient for customized corneal ablations, among other applications.

Design and applications of modified oligonucleotides

Oligonucleotides have a wide range of applications in fields such as biotechnology, molecular biology, diagnosis and therapy. However, the spectrum of uses can be broadened by introducing chemical modifications into their structures. The most prolific field in the search for new oligonucleotide analogs is the antisense strategy, where chemical modifications confer appropriate characteristics such as hybridization, resistance to nucleases, cellular uptake, selectivity and, basically, good pharmacokinetic and pharmacodynamic properties. Combinatorial technology is another research area where oligonucleotides and their analogs are extensively employed. Aptamers, new catalytic ribozymes and deoxyribozymes are RNA or DNA molecules individualized from a randomly synthesized library on the basis of a particular property. They are identified by repeated cycles of selection and amplification, using PCR technologies. Modified nucleotides can be introduced either during the amplification procedure or after selection.

Development and applications of the SWAN rating scale for assessment of attention deficit hyperactivity disorder: a literature review

This study reviewed the use of the Strengths and Weaknesses of Attention-Deficit/Hyperactivity-symptoms and Normal-behaviors (SWAN) rating scale in diagnostic and evolutive approaches to attention deficit hyperactivity disorder (ADHD) and in correlational studies of the disorder. A review of articles published in indexed journals from electronic databases was conducted and 61 articles on the SWAN scale were analyzed. From these, 27 were selected to a) examine use of SWAN in research on attention disorders and b) verify evidence of its usefulness in the areas of genetics, neuropsychology, diagnostics, psychiatric comorbidities, neuroimaging, pharmacotherapy, and to examine its statistical reliability and validity in studies of diverse populations. This review of articles indicated a growing use of the SWAN scale for diagnostic purposes, for therapy, and in research on areas other than ADHD, especially when compared with other reliable scales. Use of the scale in ADHD diagnosis requires further statistical testing to define its psychometric properties.

Clinical applications of retrograde autologous priming in cardiopulmonary bypass in pediatric cardiac surgery

Retrograde autologous priming (RAP) has been routinely applied in cardiac pediatric cardiopulmonary bypass (CPB). However, this technique is performed in pediatric patients weighing more than 20 kg, and research about its application in pediatric patients weighing less than 20 kg is still scarce. This study explored the clinical application of RAP in CPB in pediatric patients undergoing cardiac surgery. Sixty pediatric patients scheduled for cardiac surgery were randomly divided into control and experimental groups. The experimental group was treated with CPB using RAP, while the control group was treated with conventional CPB (priming with suspended red blood cells, plasma and albumin). The hematocrit (Hct) and lactate (Lac) levels at different perioperative time-points, mechanical ventilation time, hospitalization duration, and intraoperative and postoperative blood usage were recorded. Results showed that Hct levels at 15 min after CPB beginning (T2) and at CPB end (T3), and number of intraoperative blood transfusions were significantly lower in the experimental group (P<0.05). There were no significant differences in CPB time, aortic blocking time, T2-Lac value or T3-Lac between the two groups (P>0.05). Postoperatively, there were no significant differences in Hct (2 h after surgery), mechanical ventilation time, intensive care unit time, or postoperative blood transfusion between two groups (P>0.05). RAP can effectively reduce the hemodilution when using less or not using any banked blood, while meeting the intraoperative perfusion conditions, and decreasing the perioperative blood transfusion volume in pediatric patients.

Postharvest quality of cocona (Solanum sessiliflorum Dunal) stored under ambient condition

Cocona (Solanum sessiliflorum Dunal) is an important genetic resource that has been traditionally used for a variety of purposes, including food, medical and cosmetics applications. The objective of this study was evaluated the quality and the period of postharvest shelf life of cocona 'Mosquet", through the physical, chemical and physiological characterization of fruits stored under the ambient conditions. Physiologically mature fruits were harvested from an orchard, washed with tap water and soaked in a solution of the fungicide Prochloraz (49.5 g/100 L of water) for 5 minutes. After air drying, the fruits were packed in plastic containers and stored at 24 ± 2 ºC and relative humidity 60 ± 5% for 15 days. The fruits developed a respiratory climacteric respiratory patern and remained fit for consumption up to day 6 of storage, that is, without visual symptoms of loss of water and firmness. At this stage, the fruits showed firmness of 117,42 kPa, soluble solids of 6.62º Brix and citric acid of 1.22 %.

Antibacterial activity of Baccharis trimera (Less.) DC. (carqueja) against bacteria of medical interest

Baccharis trimera (Less.) (Asteraceae), popularly know as "carqueja", is a species commonly used in folk medicine for the treatment or prevention of diseases. In this context, the purpose of this work was to study the antibacterial activity of crude hydroalcoholic extract from Baccharis trimera against Gram-positive bacterial strains (Staphylococcus aureus ATCC 29213, Staphylococcus saprophyticus ATCC 15305, Staphylococcus epidermidis ATCC 12228, Enterococcus faecalis ATCC 19433) and Gram-negative bacteria (Escherichia coli EHEC ATCC 43895, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 27736, Salmonella typhi ATCC 19430) of clinical interest. Antibacterial susceptibility was evaluated by broth microdilution assay following the CLSI (formerly the NCCLS) guidelines. The extract from B. trimera showed antibacterial activity against Gram-positive bacteria and the most interesting result was obtained against S. epidermidis that presented Minimal Inhibitory Concentration of 250μg/mL. These results indicate that B. trimera have bacterisostatic potential against Gram-positive bacterial strains of medical interest and could serve as a base for further studies on the use of isolated compounds from this species as future antimicrobials.

Applications of artificial intelligence to condition-based maintenance

In this paper we discuss interesting developments of expert systems for machine diagnosis and condition-based maintenance. We review some elements of condition-based maintenance and its applications, expert systems for machine diagnosis, and an example of machine diagnosis. In the last section we note some problems to be resolved so that expert systems for machine diagnosis may gain wider acceptance in the future.