Terapia Eléctrica Funcional en el Manejo de la Disfagia / Functional Electrical therapy in the management of Dysphagia

La participación del Fonoaudiólogo en la rehabilitación neuromuscular orofacial y musculatura implicada en la mecánica deglutoria, se ha complementado con el uso de la terapia eléctrica funcional; esta carece de evidencia científica que respalde su efectividad en los procesos de recuperación funcional. Objetivo: Realizar una revisión documental sobre el uso de la terapia eléctrica funcional en el manejo de la disfagia, con el fin de crear un soporte teórico que respalde los procesos de intervención en fonoaudiología. Metodología: La revisión de la literatura se realizó en las bases de datos de Proquest, EBSCO, Scielo, Redalyc y Medic Latina. Fueron revisados artículos entre el 2008 y 2018. Para la selección de los artículos se utilizó el diagrama de flujo PRISMA (Preferred Reporting Hems for Systematic Reviews and Meta analyses). Resultados: Se revisaron 2980 artículos para exclusión por título, quedando 66 artículos en la primera depuración, de los cuales 21 fueron descartados por no cumplir con ningún criterio propuesto, 10 por repetición y 12 por no permitir el acceso al documento. Finalmente fueron considerados 23 artículos y 5 fuentes de consulta física para realizar el respectivo análisis. Conclusiones: Existe escasa evidencia científica que respalde la intervención fonoaudiológica en la disfagia con electroterapia.

The participation of the speech therapist within the orofacial neuromuscular rehabilitation and the musculature involved in swallowing mechanics, has been complemented with the use of functional electrical therapy, which has lacked scientific evidence that supports its effectiveness in faster recovery processes in terms of functionality. Objective: To carry out a documentary review of information related to the use of functional electric therapy on the management of dysphagia, to create a theoretical support that supports the processes of speech therapy intervention. Methodology: The review of the literature was carried out in the databases of Proquest, EBSCO, Scielo, Redalyc and Medic Latina. Articles were reviewed between 2008 and 2018. For the selection of the articles the PRISMA flow chart (Preferred Reporting Hems for Systematic Reviews and Meta analyzes) was used. Results: 2980 articles were reviewed for exclusion by title, leaving 66 articles in the first debugging, of which 21 were discarded for not complying with any proposed criteria, 10 for repetition and 12 for not allowing access to the document. Finally, 23 articles and 5 sources of physical consultation were considered to perform the respective analysis. Conclusions: There is little scientific evidence to support the speech therapy intervention in dysphagia with electrotherapy.

High biobased content epoxy-anhydride thermosets from epoxidized sucrose esters of Fatty acids.

Novel highly functional biobased epoxy compounds, epoxidized sucrose esters of fatty acids (ESEFAs), were cross-linked with a liquid cycloaliphatic anhydride to prepare polyester thermosets. The degree of cure or conversion was studied using differential scanning calorimetry (DSC), and the sol content of the thermosets was determined using solvent extraction. The mechanical properties were studied using tensile testing to determine Young's modulus, tensile stress, and elongation at break. Dynamic mechanical analysis (DMA) was used to determine glass-transition temperature, storage modulus, and cross-link density. The nanomechanical properties of the surfaces were studied using nanoindentation to determine reduced modulus and indentation hardness. The properties of coatings on steel substrates were studied to determine coating hardness, adhesion, solvent resistance, and mechanical durability. Compared with the control, epoxidized soybean oil, the anhydride-cured ESEFAs have high modulus and are hard and ductile, high-performance thermoset materials while maintaining a high biobased content (71-77% in theory). The exceptional performance of the ESEFAs is attributed to the unique structure of these macromolecules: well-defined compact structures with high epoxide functionality. These biobased thermosets have potential uses in applications such as composites, adhesives, and coatings.

Left Ventricular Rotation and Twist: Why Should We Learn?

The left ventricle twists in systole storing potential energy and untwists (recoils) in diastole releasing the energy. Twist aids left ventricular ejection and untwist aids relaxation and ventricular filling. Therefore, rotation and torsion are important in cardiac mechanics. However, the methodology of their investigations is limited to invasive techniques or magnetic resonance imaging. With the advent of speckle tracking echocardiography, however, rotation and torsion (twist) become familiar to echocardiographers. In this review, I outline the mechanism and influencing factors of rotation and torsion with the anticipation of the routine use of these measurements in clinical practice.

Mechanical properties and total hydroxycinnamic derivative release of starch/glycerol/Melissa officinalis extract films / Propriedades mecânicas e a liberação total hidroxicinâmicos derivados e extração de película de amido / glicerol / Melissa officinalis

The aim of this study was to investigate the mechanical properties of starch/glycerol/Melissa officinalis, a topical drug delivery system for labial herpes treatment. Four films were prepared with different concentrations of starch, glycerol, and Melissa officinalis extract. The results revealed that increasing the glycerol concentration in the film reduced elasticity modulus and tensile strength, exhibiting a plasticizing effect. The increase in free volume resulted in increased release of hydroxycinnamic derivatives expressed as rosmarinic acid.

O objetivo deste trabalho foi estudar as propriedades mecânicas e o mecanismo de liberação de um sistema tópico de liberação prolongada para o tratamento do Herpes labial a partir de filmes de amido/glicerol/extrato de Melissa officinalis, planta com comprovada atividade antiviral. Foram obtidos quatro filmes poliméricos com diferentes concentrações de amido, glicerol e extrato de Melissa officinalis os quais foram caracterizados mecanicamente e determinado o perfil de liberação de derivados hidroxicinâmicos. Os resultados demonstraram que o aumento da concentração de glicerol no filme produz uma redução no módulo de elasticidade e na tensão de deformação como conseqüência do efeito plastificante. O aumento no volume livre do polímero resultou em aumento da liberação dos derivados hidroxicinâmicos expressos como ácido rosmarínico.

The differential role of motor cortex in stretch reflex modulation induced by changes in environmental mechanics and verbal instruction.

The motor cortex assumes an increasingly important role in higher mammals relative to that in lower mammals. This is true to such an extent that the human motor cortex is deeply involved in reflex regulation and it is common to speak of "transcortical reflex loops." Such loops appear to add flexibility to the human stretch reflex, once considered to be immutable, allowing it to adapt across a range of functional tasks. However, the purpose of this adaptation remains unclear. A common proposal is that stretch reflexes contribute to the regulation of limb stability; increased reflex sensitivity during tasks performed in unstable environments supports this hypothesis. Alternatively, before movement onset, stretch reflexes can assist an imposed stretch, opposite to what would be expected from a stabilizing response. Here we show that stretch reflex modulation in tasks that require changes in limb stability is mediated by motor cortical pathways, and that these differ from pathways contributing to reflex modulation that depend on how the subject is instructed to react to an imposed perturbation. By timing muscle stretches such that the modulated portion of the reflex occurred within a cortical silent period induced by transcranial magnetic stimulation, we abolished the increase in reflex sensitivity observed when individuals stabilized arm posture within a compliant environment. Conversely, reflex modulation caused by altered task instruction was unaffected by cortical silence. These results demonstrate that task-dependent changes in reflex function can be mediated through multiple neural pathways and that these pathways have task-specific roles.

[Daedalus sive mechanicus--automated equipment and machines at the interface between mechanics and medicine]. / Daedalus sive mechanicus-- Automaten und Maschinen an der Schnittstelle zwischen Mechanik und Medizin.

Automata have always held a particular fascination. Their history leads back to their mythical ancestors, whose destinies raise considerable ethical questions about the sense of technology and about the boundaries between nature and art. In the 16th century engineers, architects and also physicians discussed the status of the ,artes mechanicae' and the machines they produced or used. Useful, sometimes dangerous, amusing and elaborate artefacts liven up their texts. Together with wonderful automata we find there also orthopaedic stretching machines and artificial limbs, whose acceptance by medical practice was anything but a matter of course.

Soybean-oil-based waterborne polyurethane dispersions: effects of polyol functionality and hard segment content on properties.

The environmentally friendly vegetable-oil-based waterborne polyurethane dispersions with very promising properties have been successfully synthesized without difficulty from a series of methoxylated soybean oil polyols (MSOLs) with different hydroxyl functionalities ranging from 2.4 to as high as 4.0. The resulting soybean-oil-based waterborne polyurethane (SPU) dispersions exhibit a uniform particle size, which increases from about 12 to 130 nm diameter with an increase in the OH functionality of the MSOL from 2.4 to 4.0 and decreases with increasing content of the hard segments. The structure and thermophysical and mechanical properties of the resulting SPU films, which contain 50-60 wt % MSOL as renewable resources, have been studied by Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis, transmission electron microscopy, and mechanical testing. The experimental results reveal that the functionality of the MSOLs and the hard segment content play a key role in controlling the structure and the thermophysical and mechanical properties of the SPU films. These novel films exhibit tensile stress-strain behavior ranging from elastomeric polymers to rigid plastics and possess Young's moduli ranging from 8 to 720 MPa, ultimate tensile strengths ranging from 4.2 to 21.5 MPa, and percent elongation at break values ranging from 16 to 280%. This work has addressed concerns regarding gelation and higher cross-linking caused by the high functionality of vegetable-oil-based polyols. This article reports novel environmentally friendly biobased SPU materials with promising applications as decorative and protective coatings.

Strength enhancement of nanostructured organogels through inclusion of phthalocyanine-containing complementary organogelator structures and in situ cross-linking by click chemistry.

Stable photoactive organogels were successfully prepared by a two-step sequence involving: 1) formation of thermoreversible organogels by use of a combination of low-molecular-weight organogelators (LMOGs) and ZnII-phthalocyanine (ZnII-Pc) moieties containing complementary organogelator structures, and 2) strength enhancement of the gels by in situ cross-linking with the aid of CuI-catalysed azide-alkyne [3+2] cycloadditions (CuAACs). The optimum click reaction was carried out between a flexible C6 aliphatic diazide and a suitable dialkyne (molar ratio 1:1) added in a low proportion relative to the organogelator system [LMOG+ZnIIPc]. The dialkyne unit was incorporated into a molecule resembling the LMOGs structure in such a way that it could also participate in the self-assembly of [LMOG+ZnIIPc]. The significant compatibility of the multicomponent photoactive organogels towards this strengthening through CuAACs allowed their sol-to-gel transition temperatures (Tgel) to be enhanced by up to 15 degrees C. The Tgel values estimated by the "inverse flow method" were in good agreement with the values obtained by differential scanning calorimetry (DSC). Rheological measurements confirmed the viscoelastic, rigid, and brittle natures of all Pc-containing gels. Transmission and scanning electron microscopy (TEM, SEM) and atomic force microscopy (AFM) revealed the fibrilar nature of the gels and the morphological changes upon cross-linking by CuAAC. Emission of a red luminescence from the dry nanoscale fibrous structure-due to the self-assembly of the Pc-containing compounds in the organogel fibres-was directly observed by confocal laser scanning microscopy (CLSM). The optical properties were studied by UV/Vis and fluorescence spectroscopy. Fluorescence, Fourier-transform infrared (FTIR) and circular dichroism (CD) measurements were also carried out to complete the physicochemical characterization of selected gels. As a proof of concept, two different organogelators (cholesterol- and diamide-based LMOGs) were successfully used to validate the general strategy.

Mechanical properties of dental zirconia ceramics changed with sandblasting and heat treatment.

Two types of tetragonal zirconia polycrystals (TZP), a ceria-stabilized TZP/Al2O3 nanocomposite (CZA) and a conventional yttria-stabilized TZP (Y-TZP), were sandblasted with 70-microm alumina and 125-microm SiC powders, then partially annealed at 500-1200 degrees C for five minutes. Monoclinic ZrO2 content was determined by X-ray diffractometry and Raman spectroscopy. Biaxial flexure test was conducted on the specimens before and after the treatments. Monoclinic ZrO2 content and biaxial flexure strength increased after sandblasting, but decreased after heat treatment. However, in both cases, the strength of CZA was higher than that of Y-TZP. Raman spectroscopy showed that a compressive stress field was introduced on the sample surface after sandblasting. It was concluded that sandblasting induced tetragonal-to-monoclinic phase transformation and that the volume expansion associated with such a phase transformation gave rise to an increase in compressive stress on the surface of CZA. With the occurrence of such a strengthening mechanism in the microstructure, it was concluded that CZA was more susceptible to stress-induced transformation than Y-TZP.

The effect of the environment on the mechanical properties of medical grade silicones.

Silicone spacers have been in use as replacement joints in the human hand for over 30 years. Since they were first used there has been a number of designs all of which have had problems with fracture. This may be due to a defect in the material caused during implantation, or by bony intrusions within the arthritic hand after implantation. The aim of this research was to investigate the effect of the environment on the mechanical properties of medical grade silicones used for human implantation. The materials were subjected to static tensile testing after various forms of ageing. The environmental conditions included temperatures of 37 and 80 degrees C and the environments of Ringer's solution, distilled water, and air. The environmental conditions employed resulted in reduced mechanical strength with ageing time of the silicones. This research supports the view that failure of silicone implants in the hand could be partly attributed to the effects of environmental ageing of the material.

Fibroblast growth factor-2-apatite composite layers on titanium screw to reduce pin tract infection rate.

Fibroblast growth factor-2 (FGF-2)-apatite composite layers were formed on anodically oxidized titanium screws to improve bone-screw interface strength and to reduce pin tract infection rate through enhanced skin tissue healing in external fixation. A calcium-containing solution supplemented with FGF-2, a phosphate-containing solution, and a sodium bicarbonate solution were mixed at a Ca/P molar ratio of 2.0 to prepare a calcium phosphate solution supersaturated with respect to calcium phosphates. Screws were individually immersed in 10 mL of the calcium phosphate solution at 37 degrees C for 2 days. Low-crystalline apatite layers incorporating FGF-2 were formed on the screw surface at FGF-2 concentrations in the supersaturated calcium phosphate solution equal to or lower than 10 mug/mL. The amounts of FGF-2 immobilized on the screws ranged from 2.3- to 2.4-mug per screw. The immobilized FGF-2 retained biological activity, as demonstrated by NIH3T3 cell proliferation. Titanium screws with the composite layer were percutaneously implanted into the bilateral proximal tibial metaphyses in rabbits for 4 weeks. The titanium screws with the composite layer formed at the optimum FGF-2 concentration showed a significantly higher bone-screw interface strength and a lower pin tract infection rate than those without the composite layer: the extraction torque and infection rates were respectively 0.230 +/- 0.073 Nm and 43.8% for the screws with the composite layer, and 0.170 +/- 0.056 Nm and 93.8% for those without the composite layer. Therefore, titanium screws with the FGF-2-apatite composite layer are useful for improving bone-screw interface strength and infection resistance in external skeletal fixation.

Particle bridging in dispersions by small charged molecules: chain length and rigidity, architecture and functional groups spatial position.

The particle bridging behaviour of dicarboxylic acid bolaform compounds such as fumaric, oxalic,trans-beta-hydromuconic, trans,trans- and cis,cis-muconic acids were evaluated in terms of their effects on the yield stress of alpha-Al(2)O(3) dispersions. The adsorption behaviour of these additives and their effects on the particle zeta potential were also determined. This study aims to understand and identify molecular factors essential for particle bridging. Very rigid compounds like trans,trans- and cis,cis-muconic and fumaric acids were identified as excellent bridging compounds from the large increase in the maximum gel strength. This strength enhancement increases with chain length and is due to more bridging molecules located in the larger spherical cap bridging area and participating in bridging. Cis,cis-muconic acid with the same chain length as fumaric acid displayed a greater bridging capability as its bolaform carboxylate groups possessed a greater lateral reach. Trans-beta-hydromuconic acid with a more flexible backbone displayed a much diminished particle bridging capability. This study has revealed a number of new molecular structural factors essential for particle bridging attribute. These are (a) the degree of backbone rigidity, (b) chain length, (c) spatial position and (d) lateral displacement of the bolaform charged group. For fumaric, trans,trans- and cis,cis-muconic acids, the maximum gel strength was not located at the pH of zero zeta potential. A particle bridging model taking into account of electrostatic repulsive interactions between the interacting particles was proposed to explain the maximum gel strength enhancement by the bolaform compounds.

Global structures of high methoxyl pectin from solution and in gels.

Images of high methoxyl orange pectin deposited from solution and high methoxyl sugar acid gels (HMSAG) were obtained by atomic force microscopy (AFM) in the tapping mode. For the first time, images of pectin deposited from water revealed that the transition from pectin networks to individual molecules or aggregates thereof occurred at concentrations between 6.5 and 13.1 microg/mL. At 6.5 microg/mL, shapes included rods, segmented rods, kinked rods, rings, branched molecules, and dense circular areas. At 13.1 microg/mL, all of these shapes were integrated into networks. These same structures were discernible in pectin high methoxyl sugar acid gels. Thus one might consider pectin networks in water at concentrations in excess of 10 microg/mL to be separate fluid precursors of networks in high methoxyl sugar acid gels. Examination of AFM images revealed that gels with "uniform" distribution of strands and pores between strands had higher gel strengths as measured by a penetrometer than gels in which strands were nonuniformly distributed and were separated by large and small spaces.

High modulus nanopowder reinforced dimethacrylate matrix composites for dental cement applications.

Results from the study of a novel, high modulus nanopowder filled resin composite are presented. This composite is developed to serve (1) as a high stiffness support to all-ceramic crowns and (2) as a means of joining independently fabricated crown core and veneer layers. Nanosized Al(2)O(3) (average particle size 47 nm) reinforcement provides stiffness across joins. Two systems are examined: Al(2)O(3) with 50:50 bis-GMA:TEGDMA monomers (ALBT) and Al(2)O(3) with pure TEGDMA (ALT). To obtain higher filler levels, surfactant is used to aid mixing and increase maximum weight percent of nanopowder filler from 72 to 80. The loading level of Al(2)O(3) has significant effects on composite properties. The elastic modulus for cured ALBT systems increases from 4.6 GPa (0 wt % filler) to 29.2 GPa (80 wt % filler). The elastic modulus for cured ALT systems increases from 3.0 GPa (0 wt % filler) to 22.9 GPa (80 wt % filler). Similarly, ALBT hardness increases from 200 MPa (0% filler) to 949 MPa (80 wt % filler), and ALT hardness increases from 93 MPa (0% filler) to 760 MPa (80 wt % filler). Our results indicate that with a generally monodispersed nanosized high modulus filler relatively high elastic modulus resin based composite cements are possible.

Conceptualization and analysis of mechanistic studies.

Much recent attention has been given to the priority for doing "mechanistic studies" of complementary and alternative medicine (CAM) modalities. A preference for such studes has been clearly indicated by the National Center for Complementary and Alternative Medicine program of funding for CAM research. It is, however, difficult to find canons by which "mechanistic" studies should be analyzed, and even harder to find a good definition of "mechanism." Social scientists have well-developed ways of approaching these issues, but their methods suffer from a fatal flaw, the ecologic mechanistic fallacy. Basic scientists fare even worse, often conducting mechanistic studies that may have no plausible mechanistic content, and that also commit the ecologic mechanistic fallacy. More methodological work on the concept of mechanism is needed at a fundamental level.

Composite films from pectin and fish skin gelatin or soybean flour protein.

Composite films were prepared from pectin and fish skin gelatin (FSG) or pectin and soybean flour protein (SFP). The inclusion of protein promoted molecular interactions, resulting in a well-organized homogeneous structure, as revealed by scanning electron microscopy and fracture-acoustic emission analysis. The resultant composite films showed an increase in stiffness and strength and a decrease in water solubility and water vapor transmission rate, in comparison with films cast from pectin alone. The composite films inherited the elastic nature of proteins, thus being more flexible than the pure pectin films. Treating the composite films with glutaraldehyde/methanol induced chemical cross-linking with the proteins and reduced the interstitial spaces among the macromolecules and, consequently, improved their mechanical properties and water resistance. Treating the protein-free pectin films with glutaraldehyde/methanol also improved the Young's modulus and tensile strength, but showed little effect on the water resistance, because the treatment caused only dehydration of the pectin films and the dehydration is reversible. The composite films were biodegradable and possessed moderate mechanical properties and a low water vapor transmission rate. Therefore, the films are considered to have potential applications as packaging or coating materials for food or drug industries.

Role of indenter material and size in veneer failure of brittle layer structures.

The roles of indenter material and size in the failure of brittle veneer layers in all-ceramic crown-like structures are studied. Glass veneer layers 1 mm thick bonded to alumina layers 0.5 mm thick on polycarbonate bases (representative of porcelain/ceramic-core/dentin) are subject to cyclic contact loading with spherical indenters in water (representative of occlusal biting environment). Two indenter materials-glass and tungsten carbide-and three indenter radii-1.6, 5.0, and 12.5 mm-are investigated in the tests. A video camera is used to follow the near-contact initiation and subsequent downward propagation of cone cracks through the veneer layer to the core interface, at which point the specimen is considered to have failed. Both indenter material and indenter radius have some effect on the critical loads to initiate cracks within the local Hertzian contact field, but the influence of modulus is weaker. The critical loads to take the veneer to failure are relatively insensitive to either of these indenter variables, since the bulk of the cone crack propagation takes place in the contact far field. Clinical implications of the results are considered, including the issue of single-cycle overload versus low-load cyclic fatigue and changes in fracture mode with loading conditions.

A novel gel formation method, microstructure and mechanical properties of calcium polysaccharide gel films.

Hydrophilic gels, formed by the interaction of calcium ions with either sodium alginate or potassium pectinate, can be deposited as a wet coating on to the surface of drug loaded pellets. If the coated pellets are dried, they could be dispensed to a patient in a capsule for oral delivery of the active drug. In contact with the aqueous fluids of the gastrointestinal tract, the gel coat will rehydrate, swell and will sustain the release of active drug from the core. In order to facilitate the development and refinement of this novel coated system, it is beneficial to have a method that can produce free gel films in a manner that closely mimics the way the gel coat is formed and deposited on the pellet surface. Traditional film producing methods would involve the spraying or depositing (by evaporation) the gel forming polysaccharide on to an inert surface, drying it and then exposing the dry film to a solution containing calcium ions. Because the film is dry before it is gelled, it is fundamentally different to the wet gel coats that are deposited on to the pellets. We have developed a method to produce wet gel films and have evaluated different manufacturing conditions in order to optimize the quality of the completed gel film. Additionally, we have used these films to assess the effect that the type of polysaccharide and the environmental conditions experienced during rehydration (pH and ionic strength) has on the mechanical properties and the microscopic morphology of the gel. Irrespective of the rehydration medium, the calcium pectinate gel films were softer, weaker and more porous, than the calcium alginate films. Although calcium alginate gels that were rehydrated in 0.1M NaCl were porous, the same films rehydrated in either water, simulated gastric fluid USP (without pepsin) or 0.1M HCl were stronger and much more dense microscopically. Furthermore, of the four different alginates that were evaluated, those with a high content of guluronic acid saccharides were the strongest but most brittle when rehydrated in water.

Development of a hand dynamometer for the control of manually applied forces.

OBJECTIVE: The aim of the study was to develop a prototype tool capable of providing instantaneous feedback about manually applied forces, and to use it to determine (1) whether force constancy can be maintained during different application postures and (2) whether sensitivity to stiffness using the tool is different from sensitivity when assessing stiffness with the hands. METHODS: Subjects were students and staff in a health sciences faculty. A series of grade II and IV mobilizing forces were delivered using a mobilizing tool, a modified JAMAR dynamometer fitted with a molded handle. Forces were executed without feedback at application points on a plinth that were near, midway, and far from the body. Thereafter, discrimination between elastic stiffness was determined with hands alone or using the tool. RESULTS: Force was maintained at grade II when the point of application was moved away from the body, but attempts to replicate grade IV mobilization forces in similar postures showed a decrease despite increased effort. Variation in force produced was substantial both within and between subjects. Stiffness discrimination was not significantly different whether hands or the tool was used. CONCLUSION: There is substantial variation in manually applied forces that could be controlled if instantaneous force readout was available. Reports of hand injury in manual therapists motivate further development of devices that maintain sensitivity and allow for control of applied force and spread the load over a greater surface area on the hands.