Optimal management of post-traumatic radioulnar synostosis

Post-traumatic radioulnar synostosis is a rare complication after forearm or elbow injury that can result in loss of motion and significant disability. Risk factors include aspects of the initial trauma and of the surgical treatment of that trauma. Surgical intervention for synostosis is the standard of care and is determined based on the location of the bony bridge. Surgical timing is recommended between 6 months and 2 years with recent advocacy for the 6- to 12-month period after radiographs demonstrate bony maturation but early enough to prevent further stiffness and contractures. For most types of synostosis, surgical resection with interposition graft is recommended. The types of materials used include synthetic, allograft, and vascularized and non-vascularized materials, but currently there is no consensus on which is the most preferable. Adjuvant therapy is not considered necessary for all cases but can be beneficial in patients with high risk factors such as recurrence or traumatic brain injury. Postoperative rehabilitation should be performed early to maintain range of motion. © 2017 Osterman and Arief

Differences in hearing acuity among “normal-hearing” young adults modulate the neural basis for speech comprehension

AbstractIn this paper, we investigate how subtle differences in hearing acuity affect the neural systems supporting speech processing in young adults. Auditory sentence comprehension requires perceiving a complex acoustic signal and performing linguistic operations to extract the correct meaning. We used functional MRI to monitor human brain activity while adults aged 18–41 years listened to spoken sentences. The sentences varied in their level of syntactic processing demands, containing either a subject-relative or object-relative center-embedded clause. All participants self-reported normal hearing, confirmed by audiometric testing, with some variation within a clinically normal range. We found that participants showed activity related to sentence processing in a left-lateralized frontotemporal network. Although accuracy was generally high, participants still made some errors, which were associated with increased activity in bilateral cingulo-opercular and frontoparietal attention networks. A whole-brain regression analysis revealed that activity in a right anterior middle frontal gyrus (aMFG) component of the frontoparietal attention network was related to individual differences in hearing acuity, such that listeners with poorer hearing showed greater recruitment of this region when successfully understanding a sentence. The activity in right aMFGs for listeners with poor hearing did not differ as a function of sentence type, suggesting a general mechanism that is independent of linguistic processing demands. Our results suggest that even modest variations in hearing ability impact the systems supporting auditory speech comprehension, and that auditory sentence comprehension entails the coordination of a left perisylvian network that is sensitive to linguistic variation with an executive attention network that responds to acoustic challenge.</jats:p

Redefinition of salinity

Two definitions of salinity have been in use since the early part of the present century (Knudsen 1901, Forch et al. 1902). According to the procedural definition, salinity is the amount (in grams) of dissolved solid material in a kilogram of seawater after all the bromine has been replaced by an equivalent quantity of chlorine, after all the carbonate has been converted to oxide, and after all of the organic matter has been destroyed...

Exploration and exploitation in the presence of network externalities

This paper examines the conditions under which exploration of a new, incompatible technologyis conducive to firm growth in the presence of network externalities. In particular, this studyis motivated bythe divergent evolutions of the PC and the workstation markets in response to a new technology: reduced instruction set computing (RISC). In the PC market, Intel has developed new microprocessors bymaintaining compatibilitywith the established architecture, whereas it was radicallyr eplaced byRISC in the workstation market. History indicates that unlike the PC market, the workstation market consisted of a large number of power users, who are less sensitive to compatibilitythan ordinaryusers. Our numerical analysis indicates that the exploration of a new, incompatible technologyis more likelyto increase the chance of firm growth when there are a substantial number of power users or when a new technologyis introduced before an established technologytakes off. (; ; ;

ALGAE TO ALKANES

Once considered infeasible and unviable, recently there has been renewed interest in the development of algae-derived transportation fuels. Currently, there are no commercialized algae to fuel ventures, and much debate is centered on the economic viability of such a process. Research conducted by NASA, among others, has expressed skepticism that terrestrially cultivated algae can ever compete with conventional fuels. The purpose of this project is to evaluate the economic feasibility of an algae-to-fuel venture that incorporates the state-of-the-art technologies available in the open literature. Our challenge is to produce 20 thousand barrels per day of n-alkane product that meets the current diesel fuel specifications. To arrive at a recommendation, separate models were built for algae cultivation, lipid extraction, and lipid processing at a scale necessary to reach this target. This analysis departs from prior studies on two major fronts. First, this analysis considers OriginOil’s new method of lipid extraction instead of conventional hexane extraction. Second, the objective of the lipid processing module is to produce n-alkanes from triglycerides, as opposed to producing FAME biodiesel. The n-alkane product from this process is comparable to petroleum-based diesel fuels. Thus it can be readily incorporated into existing energy infrastructure as a diesel blending stock or as a feedstock for other processing units in the refinery. Our economic analysis shows that an algae-to-fuel venture is profitable if the fuel is sold at $3/gallon, the current price of diesel. However, the commercialization of such a process is difficult due to the large total capital investment. At$2.2 billion, the capital investment of algae cultivation is nearly 40 times that of processing, which results in annual depreciation and fixed costs of nearly half of the revenue. Investors would be hesitant to invest such a large amount of money in an algae cultivation process where there is high uncertainty in the cost requirements. Algae-to-fuel economics can be improved by realizing higher value uses of the algae biomass. Biomass composes of over half of algae product, and their potential uses in pharmaceuticals, chemicals, and biomass power generation far surpass their value as animal feed. Proposed carbon-cap-and-trade programs may bring additional revenue. Thus, any algae-to-fuel venture should seek to optimize the value of its byproducts. Governments can support algae-to-fuel ventures by offering tax credits or mandating a market for renewable fuels, but the benefits of these measures are unclear. Additional analysis should address the uncertainties of various costs and look to reduce capital investment

Gravity model in the Korean highway

We investigate the traffic flows of the Korean highway system, which contains both public and private transportation information. We find that the traffic flow T(ij) between city i and j forms a gravity model, the metaphor of physical gravity as described in Newton's law of gravity, P(i)P(j)/r(ij)^2, where P(i) represents the population of city i and r(ij) the distance between cities i and j. It is also shown that the highway network has a heavy tail even though the road network is a rather uniform and homogeneous one. Compared to the highway network, air and public ground transportation establish inhomogeneous systems and have power-law behaviors.Comment: 13 page

Microtubule-associated protein 1B: a neuronal binding partner for gigaxonin

Giant axonal neuropathy (GAN), an autosomal recessive disorder caused by mutations in GAN, is characterized cytopathologically by cytoskeletal abnormality. Based on its sequence, gigaxonin contains an NH2-terminal BTB domain followed by six kelch repeats, which are believed to be important for protein–protein interactions (Adams, J., R. Kelso, and L. Cooley. 2000. Trends Cell Biol. 10:17–24.). Here, we report the identification of a neuronal binding partner of gigaxonin. Results obtained from yeast two-hybrid screening, cotransfections, and coimmunoprecipitations demonstrate that gigaxonin binds directly to microtubule-associated protein (MAP)1B light chain (LC; MAP1B-LC), a protein involved in maintaining the integrity of cytoskeletal structures and promoting neuronal stability. Studies using double immunofluorescent microscopy and ultrastructural analysis revealed physiological colocalization of gigaxonin with MAP1B in neurons. Furthermore, in transfected cells the specific interaction of gigaxonin with MAP1B is shown to enhance the microtubule stability required for axonal transport over long distance. At least two different mutations identified in GAN patients (Bomont, P., L. Cavalier, F. Blondeau, C. Ben Hamida, S. Belal, M. Tazir, E. Demir, H. Topaloglu, R. Korinthenberg, B. Tuysuz, et al. 2000. Nat. Genet. 26:370–374.) lead to loss of gigaxonin–MAP1B-LC interaction. The devastating axonal degeneration and neuronal death found in GAN patients point to the importance of gigaxonin for neuronal survival. Our findings may provide important insights into the pathogenesis of neurodegenerative disorders related to cytoskeletal abnormalities

Spitzer Observations of IC 2118

IC 2118, also known as the Witch Head Nebula, is a wispy, roughly cometary, ~5 degree long reflection nebula, and is thought to be a site of triggered star formation. In order to search for new young stellar objects (YSOs), we have observed this region in 7 mid- and far-infrared bands using the Spitzer Space Telescope and in 4 bands in the optical using the U. S. Naval Observatory 40-inch telescope. We find infrared excesses in 4 of the 6 previously-known T Tauri stars in our combined infrared maps, and we find 6 entirely new candidate YSOs, one of which may be an edge-on disk. Most of the YSOs seen in the infrared are Class II objects, and they are all in the "head" of the nebula, within the most massive molecular cloud of the region.Comment: Accepted to Ap