RESUMO
INTRODUCTION: With the introduction of tooth-colored restoration material, the usage of amalgam has reduced over years. However, results regarding toxicity and health concerns are conflicting. Based on the concept of recycle and reuse, we previously used an ayurvedic method for purification of excess mercury obtained from dental operatory. In the present study, we aimed to evaluate the properties of dental amalgam using commercially available and ayurvedically recycled mercury. MATERIALS AND METHODS: Samples were prepared for analysis of mean compressive strength, Vickers hardness number, and coefficient of friction dental amalgam using commercially available and ayurvedically recycled mercury. Further analysis was done using scanning electron microscopy. The data were presented on Microsoft Excel Spreadsheet 2013 and statistical analysis was done on IBM SPSS software (IBM Analytics) and OriginPro 8 software. RESULTS AND CONCLUSION: No statistically significant difference was found in properties of dental amalgam prepared using commercially available and ayurvedically recycled mercury. Although not statistically significant, early compressive strength and hardness of amalgam using ayurvedically recycled mercury were comparatively higher, which may be attributed to residual amounts of silver, tin, and copper acting as nucleating agent for faster setting reaction.
RESUMO
Wireless neural stimulators are being developed to address problems associated with traditional lead-based implants. However, designing wireless stimulators on the sub-millimeter scale (<1 mm3) is challenging. As device size shrinks, it becomes difficult to deliver sufficient wireless power to operate the device. Here, we present a sub-millimeter, inductively powered neural stimulator consisting only of a coil to receive power, a capacitor to tune the resonant frequency of the receiver, and a diode to rectify the radio-frequency signal to produce neural excitation. By replacing any complex receiver circuitry with a simple rectifier, we have reduced the required voltage levels that are needed to operate the device from 0.5 to 1 V (e.g., for CMOS) to ~0.25-0.5 V. This reduced voltage allows the use of smaller receive antennas for power, resulting in a device volume of 0.3-0.5 mm3. The device was encapsulated in epoxy, and successfully passed accelerated lifetime tests in 80°C saline for 2 weeks. We demonstrate a basic proof-of-concept using stimulation with tens of microamps of current delivered to the sciatic nerve in rat to produce a motor response.
RESUMO
La obesidad se ha identificado como un factor importante de riesgo de morbimortalidad relacionada con anestesia en obstetricia. La obesidad acentúa la mayoría de los cambios fisiológicos del embarazo. Las parturientas obesas tienen un mayor riesgo de presentar problemas médicos concomitantes o enfermedades prenatales, entre ellas la preeclampsia y la diabetes gestacional. Estas pacientes requieren valoración preoperatoria minuciosa, una preparación meticulosa y alistamiento para una vía aérea difícil, puesto que la incidencia de intubación fallida es mucho más alta en ellas. Siempre que sea posible, la anestesia regional es la mejor alternativa en este grupo de pacientes.
Obesity has been identified as a significant risk factor for anaesthesia related morbi-dity/mortality in obstetrics. Obesity compounds most of the physiological changes in pregnancy. The obese parturients are at increased risk of having either concurrent medical problems or superimposed antenatal diseases including preeclampsia and gestational diabetes. These patients need thorough preoperative assessment, meticulous preparation and preparation for difficult airway as incidence of failed intubation is many times higher in these patients. Regional anaesthesia whenever possible is the best choice in this group of patients.
Assuntos
HumanosRESUMO
Dynamic electrowetting on nanostructured silicon surfaces is demonstrated as an effective method for improving detection sensitivity in matrix-free laser desorption/ionization mass spectrometry. Without electrowetting, silicon surfaces comprising dense fields of oriented nanofilaments are shown to provide efficient ion generation and high spectral peak intensities for deposited peptides bound to the nanofilaments through hydrophobic interactions. By applying an electrical bias to the silicon substrate, the surface energy of the oxidized nanofilaments can be dynamically controlled by electrowetting, thereby allowing aqueous buffer to penetrate deep into the nanofilament matrix. The use of electrowetting is shown to result in enhanced interactions between deposited peptides and the nanofilament silicon surface, with improved signal-to-noise ratio for detected spectral peaks. An essential feature contributing to the observed performance enhancement is the open-cell nature of the nanofilament surfaces, which prevents air from becoming trapped within the pores and limiting solvent penetration during electrowetting. The combination of nanofilament silicon and dynamic electrowetting is shown to provide routine detection limits on the order of several attomoles for a panel of model peptides.
