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Respiratory complex I is a ~1-MDa proton pump in mitochondria. Its structure has been revealed in great detail, but the structural basis of its assembly, in humans involving at least 15 assembly factors, is essentially unknown. We determined cryo-electron microscopy structures of assembly intermediates associated with assembly factor NDUFAF1 in a yeast model system. Subunits ND2 and NDUFC2 together with assembly factors NDUFAF1 and CIA84 form the nucleation point of the NDUFAF1-dependent assembly pathway. Unexpectedly, the cardiolipin remodeling enzyme tafazzin is an integral component of this core complex. In a later intermediate, all 12 subunits of the proximal proton pump module have assembled. NDUFAF1 locks the central ND3 subunit in an assembly-competent conformation, and major rearrangements of central subunits are required for complex I maturation.

Youth elbow throwing injuries have been increasing among the pediatric population as more children participate in overhead sports, compete at high levels, and specialize in a single sport at an earlier age. The majority of these elbow injuries are attributable to overuse. In order to decrease the incidence of elbow injuries, recommendations and guidelines have been established and adopted by the Little League Baseball organization and other youth baseball organizations in America. There has been some success with these guidelines as they have been shown to decrease the risk of developing injury. Despite having guidelines, however, adolescents who compete in overhead sports remain at high risk of developing overuse injury, and the spectrum of injury is commonly seen in pediatric orthopedic offices. In this review, we describe six different elbow injuries associated with overuse and their specific management and treatment strategies: medial epicondyle apophysitis, medial epicondyle fracture, capitellar osteochondritis dissecans, Panner’s disease, UCL sprain, and olecranon stress injury. The purpose of this review is to highlight the spectrum of overuse elbow injuries seen in the pediatric population and briefly summarize the management of each injury.

According to Einstein’s general theory of relativity, a clock runs more slowly if it is close to a large gravitating object. This principle was highlighted in the movie “Interstellar,” in which the main character spends several hours on a planet orbiting a massive black hole, and returns to find that his young daughter has become an elderly woman. In the movie, one hour on the planet equates to seven years on Earth. The same effect can be measured on a much smaller scale by changing locations within Earth’s gravitational field. Using atomic clocks, we have compared the ticking of time at Colorado College (elevation 1845 m above sea level), at the United States Air Force Academy (elevation 2165 m), and near the summit of Pikes Peak (elevation 4288 m). Our results confirm that clocks do indeed tick more quickly at higher altitudes, in accordance with Einstein’s theory. This work was carried out as a collaboration of physics majors and faculty at Colorado College (CC) and the United States Air Force Academy (USAFA). The experimental technique is straightforward and our results can be reproduced by other students and teachers, given access to an atomic clock and reasonably large changes in elevation. Indeed, a similar endeavor has been reported by amateur clock enthusiasts.

Die Ankündigung der Libra Association, mit Libra eine private globale Währung zu emittieren, hat eine heftige Debatte über die damit verbundenen Chancen und Risiken ausgelöst. Befürworter erwarten, dass Libra das Geldsystem von seinen „staatlichen Fesseln“ befreien und den Zahlungsverkehr weltweit liberalisieren und verbilligen kann. Gegner argumentieren, dass eine private Währung erhebliche Risiken für den einzelnen Nutzer und das gesamte Finanzsystem mit sich bringt. Darüber hinaus könne Libra die Effizienz der nationalen Geldpolitiken einschränken. Dieser Beitrag erläutert das Konzept von Libra und leitet aus deren Vor- und Nachteilen das Marktpotenzial von Libra ab. Zudem werden Implikationen für die Geldpolitik und die Finanzmarktregulierung beleuchtet.

Open fractures represent 2–9% of all pediatric fractures. Standard treatment in the Emergency Department (ED) includes prompt administration of intravenous antibiotics and tetanus prophylaxis, bedside irrigation, and reduction or immobilization based on the fracture pattern. Recommendations for management of open fractures in the pediatric population are mostly based on a 1989 landmark study by Patzakis et al. which analyzed factors influencing infection rates in adults and ultimately concluded that Cefazolin was superior to fluroquinolones or no antibiotics. Subsequent studies regarding antibiotic administration in the pediatric population have been less evidence-based, often choosing antibiotic protocols based on physician discretion and institutional practice patterns. To our knowledge, there is no consensus regarding optimal antibiotic treatment protocols for pediatric open fractures. To that end, we set out to review the literature for current trends in antibiotic management of open pediatric fractures. We specifically reviewed antibiotic choice, length of treatment, and subsequent infection rates. Based on our review of the literature we found that Gustilo and Anderson Type I pediatric open fractures are generally managed with the administration of a first-generation cephalosporin (e.g. Cefazolin) within three hours of injury, bedside irrigation, and fracture stabilization in the emergency department. Types II & III fractures may be similarly managed with a first-generation cephalosporin and provisional bedside irrigation, and fracture stabilization; however, these fracture types require further debridement and fracture stabilization in the operating room. Additional gram-negative coverage (e.g. Gentamicin) is frequently added for Type 3 fractures, and in cases of farm injuries, anti-clostridial drugs such as penicillin may be added; the evidence supporting these practices, however, is lacking. Overall, we found a paucity of high-quality evidence regarding antibiotic management of open pediatric fractures.

We develop a dynamic stochastic general equilibrium (DSGE) model to study the impact of central bank digital currencies (CBDCs) on the financial sector. We focus on the effects of interest- and non- interest-bearing CBDCs during financial crises and their interactions with the effective lower bound. In addition, we analyze the role of central bank funding and a rule-based variable interest rate on CBDCs. We find that CBDCs crowd out bank deposits. However, this crowding out effect can be mitigated if the central bank chooses to provide additional central bank funds or disincentivize large-scale CBDC accumulation through low CBDC interest rates.

General relativity predicts that clocks run more slowly near massive objects. The effect is small---a clock at sea level lags behind one 1000 m above sea level by only 9.4 ns/day. Here, we demonstrate that a measurement of this effect can be done by undergraduate students. Our paper describes an experiment conducted by undergraduate researchers at Colorado College and the United States Air Force Academy to measure gravitational time dilation. The measurement was done by comparing the signals generated by a GPS frequency standard (sea-level time) to a Cs-beam frequency standard at seven different altitudes above sea level. We found that our measurements are consistent with the predictions of general relativity.

Athletic Pubalgia, more commonly known as sports hernia, is defined as chronic lower abdominal and groin pain without the presence of a true hernia. It is increasingly recognized in athletes as a source of groin pain and is often associated with other pathology. A comprehensive approach to the physical exam and a strong understanding of hip and pelvic anatomy are critical in making the appropriate diagnosis. Various management options are available. We review the basic anatomy, patholophysiology, diagnostic approach and treatment of athletic pubalgia as well as discuss associated conditions such as femoroacetabular impingement. [Full article available at http://rimed.org/rimedicaljournal-2016-10.asp].

Acute compartment syndrome is an orthopedic surgical emergency and may result in devastating complications in the setting of delayed or missed diagnosis. Compartment syndrome has a variety of causes, including posttraumatic or postoperative swelling, external compression, burns, bleeding disorders, and ischemia-reperfusion injury. Rare cases of pediatric acute compartment syndrome in the setting of acute myeloid leukemia and, even less commonly, chronic myeloid leukemia have been reported. The authors report the first known case of pediatric acute compartment syndrome in a patient without a previously known diagnosis of chronic myeloid leukemia. On initial examination, an 11-year-old boy presented with a 2-week history of progressive left calf pain and swelling after playing soccer. Magnetic resonance imaging scan showed a hematoma in the left superficial posterior compartment. The patient had unrelenting pain, intermittent lateral foot parethesias, and inability to bear weight. Subsequently, he was diagnosed with acute compartment syndrome and underwent fasciotomy and evacuation of a hematoma. Laboratory results showed an abnormal white blood cell count of 440×10 9 /L (normal, 4.4–11×10 9 ) and international normalized ratio of 1.3 (normal, 0.8–1.2). Further testing included the BCR-ABL1 fusion gene located on the Philadelphia chromosome, leading to a diagnosis of chronic myeloid leukemia. Monotherapy with imatinib mesylate (Gleevec) was initiated. This report adds another unique case to the growing literature on compartment syndrome in the pediatric population and reinforces the need to consider compartment syndrome, even in unlikely clinical scenarios.