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Mini-sabbaticals are formal short-term training and educational experiences away from an investigator’s home research unit. These may include rotations with other research units and externships at government research or regulatory agencies, industry and non-profit programs, and training and/or intensive educational programs. The National Institutes of Health have been encouraging training institutions to consider offering mini-sabbaticals, but given the newness of the concept, limited data are available to guide the implementation of mini-sabbatical programs. In this paper, we review the history of sabbaticals and mini-sabbaticals, report the results of surveys we performed to ascertain the use of mini-sabbaticals at Clinical and Translational Science Award hubs, and consider best practice recommendations for institutions seeking to establish formal mini-sabbatical programs.
Superior semicircular canal dehiscence affects the auditory and vestibular systems due to a partial defect in the canal's bony wall. In most cases, sound- and pressure-induced vertigo are present, and are sometimes accompanied by pulse-synchronous tinnitus.
We describe a 50-year-old man with superior semicircular canal dehiscence whose only complaints were head rotation induced tinnitus and autophony. Head rotation in the plane of the right semicircular canal with an angular velocity exceeding 600°/second repeatedly induced a ‘cricket’ sound in the patient's right ear. High resolution temporal bone computed tomography changes, and an elevated umbo velocity, supported the diagnosis of superior semicircular canal dehiscence.
In addition to pulse-synchronous or continuous tinnitus, head rotation induced tinnitus can be the only presenting symptom of superior semicircular canal dehiscence without vestibular complaints. We suggest that, in our patient, the bony defect of the superior semicircular canal (‘third window’) might have enhanced the flow of inner ear fluid, possibly producing tinnitus.
To describe a series of five patients with isolated fracture of the manubrium of the malleus.
Retrospective case series.
Five patients aged 44–64 years with isolated fracture of the manubrium who presented to our institution over a five-year period (2000–2005).
All patients presented with a history of digitally manipulating the external auditory canal, leading to the manubrial fracture, which we presume was due to a suction-type mechanism. Otomicroscopy often revealed a break in the smooth contour of the manubrium. All patients had air–bone gaps on audiometry, especially at higher frequencies. Tympanometry showed hypermobility of the tympanic membrane in four patients who were tested. Laser-Doppler vibrometry revealed increased umbo velocity in four out of five patients. Four patients were treated conservatively. One patient underwent exploratory tympanotomy with successful ossiculoplasty.
Isolated fracture of the manubrium is a rare condition which may present as sudden-onset hearing loss after digital manipulation of the external auditory canal. The diagnosis can be made on the basis of otomicroscopy, audiometry, tympanometry and laser-Doppler vibrometry. Conservative treatment is often successful.
Most patients with the Mustard procedure are now adults. To date, however, there have been few reports on resting and exercise hemodynamics in a large population of adults with this circulation. The aim of this study is to describe such parameters in one of the largest and oldest populations of adults with the Mustard procedure. The database of the University of Toronto Congenital Cardiac Centre for Adults was examined to identify 84 adults with the Mustard procedure who have undergone cardiopulmonary exercise tests. Magnetic resonance imaging and echocardiography studies were obtained in order to assess right ventricular size, function and baseline hemodynamics. Patients achieved lower maximum uptake of oxygen, maximal heart rate, forced vital capacity, forced expiratory volume in 1 second, and oxygen saturations at maximal exercise compared to a healthy population. Magnetic resonance imaging showed significantly different right ventricular ejection fractions between patients and controls. There were no effects of operative variables or preoperative hemodynamics on current exercise capacity. Patients after the Mustard procedure have subnormal exercise capacities. Factors such as chronotropic incompetence, peripheral deconditioning, and impaired lung function may be responsible for these results.
Textured superconducting films of YbBa2Cu3O7−δ were grown on single crystals of MgO (100) and SrTiO3 (100) by oxidation of a liquid alloy precursor. The substrates were coated by dipping them in molten YbBa2Cu3 (m.p. ~870 °C). After removal from the melt, the liquid layers on the substrates were oxidized in pure oxygen to form the tetragonal oxide phase, i.e., YbBa2Cu3O7−δ, then annealed at 500 °C to obtain the superconducting orthorhombic phase of the same compound. The microstructure of the films obtained in this way was found to be related to the nature of the substrate as well as to processing variables that included oxidation temperature and oxidation time. Films grown on MgO (100) showed c-axis texture as well as a random growth structure. Films prepared on SrTiO3 (100) showed either a c-axis texture or a mixture of c-axis and a-axis texture. The superconducting properties of the as-prepared films and the effects of key process parameters on film quality and microstructure are presented and discussed.
The growth and stability of the (Bi1-xPbx)2Sr2Ca2Cu3Oy (Bi-2223) phase contained in silver-sheathed wires has been investigated by a combination of x-ray diffraction, scanning electron microscopy, energy dispersive x-ray analysis, and transmission electron microscopy. Silver tubes loaded with Bi-2223 precursor powders were processed into filaments using established metallurgical techniques. The filaments were then heat-treated at selected temperatures (800 to 845°C) for a range of times (10 to 6000 min) in a 7.5% oxygen atmosphere. From these studies it has been possible to investigate the time-temperature-oxygen pressure domains wherein Bi2Sr2CaCu2O8 (Bi-2212) + second phases transform to Bi-2223. Fractional conversion (Bi-2212 --> Bi-2223) versus time data show good conformance to the kinetic model for a diffusion-controlled reaction at the interface between thin sheets and a fine powder or a fluid. Quenching experiments also reveal that the Bi-2223 phase is stable in a limited temperature interval between 810 and 830°C.
Textured superconducting films of YbBa2Cu3O7-δ supported on single and polycrystalline substrates were prepared by oxidation of a liquid precursor alloy. The substrates were coated by dipping them into a molten alloy (YbBa2Cu3, m.p. ∼870°C), withdrawing them from the melt, then oxidizing the adhering liquid alloy layer to the corresponding oxide phase, i.e., YbBa2Cu3O7-δ. Samples prepared in this way exhibited a superconducting transition at ∼80 K following annealing in pure O2 at 500°C. With SrTiO3 (100) and MgO (100) substrates, evidence was seen for the epitaxial growth of YbBa2Cu3O7-δ crystals having their c-axis parallel to the  direction of the substrate. For polycrystalline MgO, x-ray diffraction and microstructural examination showed that the high-Tc crystallites in the films were also oriented with their c-axis perpendicular to the substrate surface, but the a and b axes directions were randomly oriented rather than epitaxial.
The caloric test response from the unaffected ear in a case of acoustic neuroma may be normal, hypoactive or hyperactive; each has a different pathophysiological connotation: a normal response is the anticipated finding; a hyperactive contralateral response is due to the presence of a large neuroma with brainstem compression; and a hypoactive response may result from several factors, such as lack of mental alertness during the test, drugs like barbiturates, raised intracranial tension, or the presence of bilateral neuromas.
The bithermal caloric test remains, four decades after its first description, the single most valuable test of vestibular function. However, there are several variations described in the exact procedure of caloric stimulation and in the method of evaluating and representing the test results. For the past 10 years, we have followed a procedure using a constant standardized stimulus and a particular system for caloric nystagmus representation, viz., the Butterfly Chart, and have found it to be very satisfactory. This paper describes our experience with the use of the Butterfly Chart and its clinical application in over 4,500 cases.
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