Recurring Sacral Stress Fractures in the Male Distance Runner

Reccurring Sacral Stress Fractures in the Male Distance Runner Waugh TJ, Stoller GL, Brooks EK, Dailey SW: Miami University Oxford, Ohio Background: A twenty year old male collegiate distance runner (170 cm and 62 kg) complained of low back pain in March 2015. The patient reported right sided low back tightness that felt like a bad spasm traveling from the lower back down into the lower leg. History of this runner revealed a non-displaced stress fracture in the left sacral ala with a stress reaction on the right sacral ala in November 2013. In April 2014, the distance runner possessed yet another sacral stress fracture. In March 2015, an assessment was made that the patient presented an acute case of piriformis syndrome due to lack of athletic participation. As two weeks went by with no positive results through rehabilitation, worsening pain, and given the pre-existing conditions of the patient, the Team Physician ordered an MRI. Differential Diagnosis: It is possible that the runner could have had an acute disc herniation, muscle strain, degenerative disc disease, or spondylolisthesis. A vertebral compression fracture, sacroiliac joint dysfunction, lumbar facet arthropathy, and sciatica are all differential diagnoses that the clinicians in this case needed to be aware of. It is also important to assess the possibilities of a lumbosacral strain and a sacroiliac joint sprain. Treatment: The MRI report revealed a high grade stress reaction in the right sacral ala. A non-displaced stress fracture in the right superior portion of the left sacral ala was also discovered. The patient was told to rest without any exercise for four to six weeks. After the stress fracture was resolved, the athlete has been encouraged not to participate in any repeated load-bearing types of activities until the source of the problem has been identified. Uniqueness: There is an uncommon nature of sacral stress fractures in males. It is important to realize that individuals who are constantly participating in repeating load-bearing activities are more prone to sacral stress fractures. Sacral stress fractures normally present themselves in women who have the female athlete triad. Research has shown that the influence of energy balance and hormonal fluctuations are significant factors associated with injuries in amenorrheic female athletes. The testosterone levels in young men normally lead to healthy and strong bones. This case report is a prime example that has the potential to teach clinicians all over to always look at the big picture and keep in mind all of the possible differential diagnoses. Conclusions: Physician's have hypothesized that the calcium level in this patient is too high which is causing parathyroid levels to decrease, resulting in low bone density. Since calcium and the parathyroid hormone have an inverse relationship, moderation between the two is essential. However, if one is too high, the other is too low decreasing bone density. Another hypothesis is that low testosterone levels in the patient are causing low bone density. This rare case is far from over as there is numerous investigative work to still be done. Clinical Application: Correctly diagnosing a sacral stress fracture is very difficult due to the wide range of differential diagnoses that its symptoms can present. Clinicians should never rule out the possibility of a sacral stress fracture when clients present low back pain, diffuse buttocks pain, and a history of repetitive loading actively. Although the clinicians in this case did not originally think this injury was another sacral stress fracture, they never ruled out the possibility due to the patient's described pain and pre-existing conditions. The clinicians in this report considered all possible diagnoses before making an assessment. Further research still needs to be performed in order to provide the most effective treatment and outcomes for future patients. Word Count: 59

The role of the equation of state and the space-time dimension in spherical collapse

We study the spherically symmetric collapse of a fluid with non-vanishing radial pressure in higher dimensional space-time. We obtain the general exact solution in the closed form for the equation of state ($P_r = \gamma \rho$) which leads to the explicit construction of the root equation governing the nature (black hole versus naked singularity) of the central singularity. A remarkable feature of the root equation is its invariance for the three cases: (${D+1}, {\gamma = -1}$), (${D}, {\gamma = 0}$) and (${D - 1}, {\gamma = 1}$) where $D$ is the dimension of space-time. That is, for the ultimate end result of the collapse, $D$-dimensional dust, ${D+1}$ - AdS (anti de Sitter)-like and ${D-1}$ - dS-like are absolutely equivalent.Comment: 4 Pages, RevTeX, no figures, minor changes, new references added, Detailed version to follo

Magnetic Resonance

Contains research objectives and reports on three research projects

Spherically symmetric static solution for colliding null dust

The Einstein equations are integrated in the presence of two (incoming and outgoing) streams of null dust, under the assumptions of spherical symmetry and staticity. The solution is also written in double null and radiation coordinates and it is reinterpreted as an anisotropic fluid. Interior matching with a static fluid and exterior matching with the Vaidya solution along null hypersurfaces is discussed. The connection with two-dimensional dilaton gravity is established.Comment: 12 pages, 7 figures, to appear in Phys. Rev.

Measurement of Stress Profiles by Phase Contrast Techniques

An acoustic wave pissing through a material has its velocity changed when stress is applied. This is due to changes in the third order elastic constant and the density of the material. By using a small diameter beam or a focused beam Incident on a metal and reflected from both its front and back surfaces, It is possible to measure the difference in phase of the two reflected waves; the beam Itself can be scanned over the surface of the material. Three kinds of measurements will be shown. The first relates the change of velocity of a compressional wave to the applied stress taken \u27in an MTS testing system. The second shows a scan of the profile of the velocity change around a circular defect. The third is an image of the stressed region around a circular defect obtained with a scanned electronically focused system operating in a phase contrast mode

Force balance and membrane shedding at the Red Blood Cell surface

During the aging of the red-blood cell, or under conditions of extreme echinocytosis, membrane is shed from the cell plasma membrane in the form of nano-vesicles. We propose that this process is the result of the self-adaptation of the membrane surface area to the elastic stress imposed by the spectrin cytoskeleton, via the local buckling of membrane under increasing cytoskeleton stiffness. This model introduces the concept of force balance as a regulatory process at the cell membrane, and quantitatively reproduces the rate of area loss in aging red-blood cells.Comment: 4 pages, 3 figure

Work extraction in the spin-boson model

We show that work can be extracted from a two-level system (spin) coupled to a bosonic thermal bath. This is possible due to different initial temperatures of the spin and the bath, both positive (no spin population inversion) and is realized by means of a suitable sequence of sharp pulses applied to the spin. The extracted work can be of the order of the response energy of the bath, therefore much larger than the energy of the spin. Moreover, the efficiency of extraction can be very close to its maximum, given by the Carnot bound, at the same time the overall amount of the extracted work is maximal. Therefore, we get a finite power at efficiency close to the Carnot bound. The effect comes from the backreaction of the spin on the bath, and it survives for a strongly disordered (inhomogeneously broadened) ensemble of spins. It is connected with generation of coherences during the work-extraction process, and we derived it in an exactly solvable model. All the necessary general thermodynamical relations are derived from the first principles of quantum mechanics and connections are made with processes of lasing without inversion and with quantum heat engines.Comment: 30 pages, 6 figure

Strength Training for Adolescents with cerebral palsy (STAR): study protocol of a randomised controlled trial to determine the feasibility, acceptability and efficacy of resistance training for adolescents with cerebral palsy

Introduction: Gait is inefficient in children with cerebral palsy, particularly as they transition to adolescence. Gait inefficiency may be associated with declines in gross motor function and participation among adolescents with cerebral palsy. Resistance training may improve gait efficiency through a number of biomechanical and neural mechanisms. The aim of the Strength Training for Adolescents with cerebral palsy (STAR) trial is to evaluate the effect of resistance training on gait efficiency, activity and participation in adolescents with cerebral palsy. We also aim to determine the biomechanical and neural adaptations that occur following resistance training and evaluate the feasibility and acceptability of such an intervention for adolescents with cerebral palsy. Methods and analysis: 60 adolescents (Gross Motor Function Classification System level I–III) will be randomised to a 10-week resistance training group or a usual care control group according to a computer generated random schedule. The primary outcome is gait efficiency. Secondary outcomes are habitual physical activity, participation, muscle–tendon mechanics and gross motor function. General linear models will be used to evaluate differences in continuous data between the resistance training and usual care groups at 10 and 22 weeks, respectively. A process evaluation will be conducted alongside the intervention. Fidelity of the resistance training programme to trial protocol will be quantified by observations of exercise sessions. Semi structured interviews will be conducted with participants and physiotherapists following the resistance training programme to determine feasibility and acceptability of the programme. Ethics and dissemination: This trial has ethical approval from Brunel University London’s Department of Clinical Sciences’ Research Ethics Committee and the National Research Ethics Service (NRES) Committee London—Surrey Borders. The results of the trial will be submitted for publication in academic journals, presented at conferences and distributed to adolescents, families and healthcare professionals through the media with the assistance of the STAR advisory group

A Strategy for a Global Observing System for Verification of National Greenhouse Gas Emissions

Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).With the risks of climate change becoming increasingly evident, there is growing discussion regarding international treaties and national regulations to lower greenhouse gas (GHG) emissions. Enforcement of such agreements is likely to depend formally upon national and sectoral emission reporting procedures (sometimes referred to as “bottom-up” methods). However, for these procedures to be credible and effective, it is essential that these reports or claims be independently verified. In particular, any disagreements between these “bottom-up” emission estimates, and independent emission estimates inferred from global GHG measurements (so-called “top-down” methods) need to be resolved. Because emissions control legislation is national or regional in nature, not global, it is also essential that “top-down” emission estimates be determined at these same geographic scales. This report lays out a strategy for quantifying and reducing uncertainties in greenhouse gas emissions, based on a comprehensive synthesis of global observations of various types with models of the global cycles of carbon dioxide and other greenhouse gases that include both the natural and human influences on these cycles. The overall goal is to establish a global observing and estimation system that incorporates all relevant available knowledge (physical, biogeochemical, technological and economic) in order to verify greenhouse gas emissions, as a key component of any global GHG treaty.Lockheed Martin Corporation and the MIT Joint Program on the Science and Policy of Global Change, which is funded by a consortium of government, industry and foundation sponsors