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Objectives: To summarize the clinical characteristics and outcomes of pediatric sports-related concussion (SRC) patients who were evaluated and managed at a multidisciplinary pediatric concussion program and examine the healthcare resources and personnel required to meet the needs of this patient population. Methods: We conducted a retrospective review of all pediatric SRC patients referred to the Pan Am Concussion Program from September 1st, 2013 to May 25th, 2015. Initial assessments and diagnoses were carried out by a single neurosurgeon. Return-to-Play decision-making was carried out by the multidisciplinary team. Results: 604 patients, including 423 pediatric SRC patients were evaluated at the Pan Am Concussion Program during the study period. The mean age of study patients was 14.30 years (SD: 2.32, range 7-19 years); 252 (59.57%) were males. Hockey (182; 43.03%) and soccer (60; 14.18%) were the most commonly played sports at the time of injury. Overall, 294 (69.50%) of SRC patients met the clinical criteria for concussion recovery, while 75 (17.73%) were lost to follow-up, and 53 (12.53%) remained in active treatment at the end of the study period. The median duration of symptoms among the 261 acute SRC patients with complete follow-up was 23 days (IQR: 15, 36). Overall, 25.30% of pediatric SRC patients underwent at least one diagnostic imaging test and 32.62% received referral to another member of our multidisciplinary clinical team. Conclusion: Comprehensive care of pediatric SRC patients requires access to appropriate diagnostic resources and the multidisciplinary collaboration of experts with national and provincially-recognized training in TBI.
In our x-ray calorimetry effort, we have developed several techniques which may be helpful to other groups working in this field. We are studying several different monolithic and composite calorimeter designs. In our readout configuration, the preamplifier circuit employs negative voltage feedback which allows us to accurately measure the temporal profile of the thermal pulse produced by an x-ray absorbed in a micro-calorimeter. Rise times of less than two microseconds have been observed in monolithic devices operating at .3 K. Furthermore, the feedback preamplifier can be configured for either positive or negative electro-thermal feedback. This preamplifier system is followed by an analog pulse shaping amplifier with a frequency response that can be adjusted to yield the maximum signal to noise ratio for a given thermal response of the calorimeter. In addition, we have developed several diagnostic procedures which have been useful in determining the operating and noise characteristics of our devices. These include an infrared light-emitting diode which flashes a discrete amount of energy on to the calorimeter, and a capacitively coupled test input to the preamplifier which allows us to directly determine the total noise in the thermal detection system. Finally, we are developing an adiabatic demagnetization refrigerator with a temperature control system that is designed to stabilize the 0.1 K cold stage to better than 8 μK. This is required for a resistive thermal detector with resolving power of 1000.
Background: Transient ischemic attack (TIA) and minor stroke are associated with a substantial risk of subsequent stroke; however, there is uncertainty about whether such patients require admission to hospital for their initial management. We used data from a clinical stroke registry to determine the frequency and predictors of hospitalization for TIA or minor stroke across the province of Ontario, Canada. Methods: The Ontario Stroke Registry collects information on a population-based sample of all patients seen in the emergency department with acute stroke or TIA in Ontario. We identified patients with minor ischemic stroke or TIA included in the registry between April 1, 2008, and March 31, 2011, and used multivariable analyses to evaluate predictors of hospitalization. Results: Our study sample included 8540 patients with minor ischemic stroke or TIA, 47.2% of whom were admitted to hospital, with a range of 37.6% to 70.3% across Ontario’s 14 local health integration network regions. Key predictors of admission were preadmission disability, vascular risk factors, presentation with weakness, speech disturbance or prolonged/persistent symptoms, arrival by ambulance, and presentation on a weekend or during periods of emergency department overcrowding. Conclusions: More than one-half of patients with minor stroke or TIA were not admitted to the hospital, and there were wide regional variations in admission patterns. Additional work is needed to provide guidance to health care workers around when to admit such patients and to determine whether discharged patients are receiving appropriate follow-up care.
Background: This study examines whether abnormal blood hemoglobin concentration (bHB) is associated with worse clinical outcomes and poorer prognosis after acute ischemic stroke. Methods: We included data from the Registry of the Canadian Stroke Network on consecutive patients with ischemic stroke who were admitted between July/2003 and March/2008. Patients were divided into groups as follows: low bHB, normal bHB, and high bHB. Primary outcome measures were the frequency of moderate/severe strokes on admission (Canadian Neurological Scale: <8), greater degree of disability at discharge (modified Rankin score: 3-6), and 30-day and 90-day mortality. Results: Higher bHB than the superior normal limit is associated with greater degree of impairment (OR=1.45, 95%CI: 1.06-1.95, p=0.0195) and disability (OR=1.49, 95%CI: 1.03-2.15, p=0.0331), and higher 30-day mortality (HR=1.98, 95%CI: 1.44-2.74, p<0.0001) after adjustment for major potential confounders. The Kaplan-Meier curves indicate that abnormal bHB is associated with higher mortality after acute ischemic stroke (p<0.0001). Lower bHB than the inferior normal limit is associated with longer stay in the acute stroke care center (OR=1.11, 95%CI: 1.02-1.22, p=0.017). Conclusions: Polycythemia on the initial admission is associated with poorer prognosis regarding the degree of impairment and disability, and 30-day mortality after an acute ischemic stroke. Anemia on admission is associated with longer stay in the acute stroke center.
Background: We hypothesized that abnormal blood platelet count (BPC) is associated with poorer outcomes after acute ischemic stroke. Methods: We included data from the Registry of the Canadian Stroke Network on consecutive patients with acute ischemic stroke admitted between July/2003 and March/2008. Patients were divided into groups as follows: low BPC (<150,000/mm3), normal BPC (150,000 to 450,000/mm3) and high BPC (>450,000/mm3). Primary outcome measures were the frequency of moderate/severe strokes on admission (Canadian Neurological Scale: <8), greater degree of disability at discharge (modified Rankin score: 3-6), and 30-day and 90-day mortality. Results: We included 9,230 patients. Both low and high BPC were associated with higher 30-day mortality (p=0.0103) and 90-day mortality (p=0.0189) following acute ischemic stroke. The Kaplan-Meier curves indicate that abnormal BPC is associated with greater mortality after acute ischemic stroke (p=0.0002). Nonetheless, abnormal BPC was not associated with degree of impairment (p=0.3734), degree of disability (p=0.684), or length of stay (LOS) in the acute stroke care center (p=0.9541) after adjustment for major potential confounders. Conclusions: In patients with acute ischemic stroke, thrombocytopenia and thrombocytosis on the initial admission is associated with higher mortality after stroke. Abnormal BPC does not adversely affect the degree of impairment and disability, or LOS in the acute care center after acute ischemic stroke.
Long space flights and planetary settlement will require sources of nutrition and chemicals that must be generated in space. This will include not only amino acids and vitamins but also oxygen, all of which can be generated by means of biosynthesis. Synthetic biology has the potential to generate organisms designed for supplying human nutritional needs in space. Photosynthetic microbes may be ideal for this purpose, as they are more efficient per volume cultivated than green plants at conversion of light to chemical energy, biomass and nutritional molecules. In addition, microbes are easier and faster to genetically engineer, facilitating not only design and terrestrial manufacture of organisms optimized for growth and nutrient production in the artificial conditions of space, but superior ability in space to develop organisms suited to newly discovered environments. The rapid ability to adapt and create new microbes to suit new circumstances when in space offers significant potential for risk reduction. Development of sun-driven microbial production of nutritional chemicals would also have terrestrial benefits in commerce and sustainability. A synthetic biology approach to chemical production would not be based on fossil fuels as such fuels do not exist on other planets. This approach would highlight a synergistic relationship between outer space and ‘spaceship earth’, illustrating NASA's role in stimulating technology development with terrestrial application. Two specific approaches deserve consideration: production by traditional photosynthetic microbes, or by the newly appreciated capacity of some bacteria to absorb electric current (e.g. solar panels) to drive metabolism. Palatability and sensory stimulation are a key part of food consumption and could be engineered into microbes. As a first step, NASA should test a bioreactor in which genetically engineered, nutrient-producing photosynthetic bacteria are grown and harvested in space.
The puzzles regarding the magnitude of the free electron mobility in hydrogenated amorphous silicon are examined. It is suggested that highlevel double injection produces a metastable increase in the carrier mobility by neutralizing positively and negatively charged defect states thereby eliminating long-range potential fluctuations. Since these defect states cannot be neutralized under low-level or single injection, they both contribute to the modulation of the conduction band and increase the freecarrier scattering. If the latter is the predominant scattering mechanism, the neutralization of charged defects directly leads to a mobility increase under double-injection conditions. We discuss the various implications of this model, and present recent experimental results in agreement with these ideas.