bluuebunny/crossref_metadata_2025 huggingface dataset:
Colon carcinoma discovered in an adolescent during inguinal hernia repair
Authors: LeClair LCDR Lawrence L. , Mitchell CDR Craig S.
Published: June 2017

Colon carcinoma is an unusual tumor during childhood. The authors report a case of metastatic colonic adenocarcinoma diagnosed in a 14-year-old boy during inguinal hernia repair. To the authors' knowledge, this is the first reported case of this rare disease presenting as an inguinal hernia.
Team physician preferences at National Collegiate Athletic Association Division I universities
Authors: Stockard Alan R.
Published: June 2017

Virtually all National Collegiate Athletic Association (NCAA) Division I universities have physicians who evaluate and treat athletic injuries and other medical conditions. The relationship of these physicians to these institutions ranges from a very loose arrangement to full-time employment. The specialties of the physicians working with the athletes of NCAA Division I universities vary as well. This study attempts to determine the specialty of current team physicians at NCAA Division I universities and their qualifications as well as the preferences of athletic directors when they are seeking to employ a team physician for their university. By comparing IA and non-IA Division I institutions, an attempt is made to determine the possible reasons for differences. This information will then be useful both for physicians-in-training who aspire to be team physicians at the university level and for administrators at these institutions who will be recruiting physicians with the most desirable credentials in the future.
Observatory clues to aid in the diagnosing of diastasis symphysis pubis: an underreported complication of parturition
Authors: Spaeth, Donald G.
Published: June 2017

Diagnosis of diastasis symphysis pubis in the postpartum period need not depend on radiographic findings. This diagnosis can be made with simple observation techniques. Entertaining a high index of suspicion and observation of the patient are the most important contributions the physician can make. Parameters triggering a tentative diagnosis would include, but not be limited to, a large infant, a small pelvis, a rapid second stage of delivery, or application of forces to abduct the thighs. The diagnosis of diastasis symphysis pubis should be ruled out if thefollowing conditions are present postpartum: the flattened abdomen (the postpartum "pooch" is absent); the patient is incontinent of urine when changing position from supine/prone to upright; the patient has pain in the hips or sacral region when walking; or the patient waddles when walking. The change in gait, or the pain on walking may not be noticed until 24 hours or more after delivery. However, the change in abdominal contour and incontinence is noticed immediately. Using these observational clues, the physician can institute treatment sooner, thereby expediting recovery.
Martial arts injuries
Authors: Wilkerson Leonard A.
Published: June 2017

In the United States, approximately 1.5 million to 2 million persons practice the martial arts. It is the general belief that martial arts are safe, with little thought given to the physical forces involved. Some enthusiasts gravitate to the martial arts to learn self-defense, whereas others participate to improve cardiovascular fitness, flexibility, and self-esteem. Some join for the structured exercise programs, whereas others desire the artistic expression or have a need to compete. Injuries involve the head and neck region, trunk, and extremities. Soft tissue trauma, hematomas, and lacerations are some of the most common injuries. Occasionally fractures occur, most often involving the hands and digits. The neurosurgical literature indicates that wearing headgear increases the shearing injury to nerve fibers and neurons in the brain in proportion to the degree of acceleration to the head. Three case presentations illustrate death resulting from anterior chest trauma.
Revisiting epiglottitis: a protocol--the value of lateral neck radiographs
Authors: Ragosta Kevin G. , Orr Richard , RN Mary Jo Detweiler,
Published: June 2017

A retrospective review was done on the medical records (March 1986 through December 1989) of patients referred to Pittsburgh Children's Hospital with the presumptive diagnosis of epiglottitis. Data obtained included age, final diagnosis, referring physician's radiographic evaluation/interpretation, procedures (intubation, IV administered, aerosol, cultures obtained), transport times, and long-term morbidity and mortality. The diagnostic value of lateral neck radiographs was analyzed. Lateral neck radiographs were found to be of little value in the primary evaluation of epiglottitis. Rather, skilled personnel, using an established protocol, did limit morbidity and mortality in patients with symptoms consistent with epiglottitis. All medical centers should develop a protocol for management of patients presenting with symptoms suggestive of epiglottitis.
New data towards the development of a comprehensive taphonomic framework for the Late Jurassic Cleveland-Lloyd Dinosaur Quarry, Central Utah
Authors: Peterson Joseph E. , Warnock Jonathan P. , Eberhart Shawn L. , Clawson Steven R. , Noto Christopher R.
Published: June 2017

The Cleveland-Lloyd Dinosaur Quarry (CLDQ) is the densest deposit of Jurassic theropod dinosaurs discovered to date. Unlike typical Jurassic bone deposits, it is dominated by the presence ofAllosaurus fragilis. Since excavation began in the 1920s, numerous hypotheses have been put forward to explain the taphonomy of CLDQ, including a predator trap, a drought assemblage, and a poison spring. In an effort to reconcile the various interpretations of the quarry and reach a consensus on the depositional history of CLDQ, new data is required to develop a robust taphonomic framework congruent with all available data. Here we present two new data sets that aid in the development of such a robust taphonomic framework for CLDQ. First, x-ray fluorescence of CLDQ sediments indicate elevated barite and sulfide minerals relative to other sediments from the Morrison Formation in the region, suggesting an ephemeral environment dominated by periods of hypereutrophic conditions during bone accumulation. Second, the degree of abrasion and hydraulic equivalency of small bone fragments dispersed throughout the matrix were analyzed from CLDQ. Results of these analyses suggest that bone fragments are autochthonous or parautochthonous and are derived from bones deposited in the assemblage rather than transported. The variability in abrasion exhibited by the fragments is most parsimoniously explained by local periodic re-working and re-deposition during seasonal fluctuations throughout the duration of the quarry assemblage. Collectively, these data support previous interpretations that the CLDQ represents an attritional assemblage in a poorly-drained overbank deposit where vertebrate remains were introduced post-mortem to an ephemeral pond during flood conditions. Furthermore, while the elevated heavy metals detected at the Cleveland-Lloyd Dinosaur Quarry are not likely the primary driver for the accumulation of carcasses, they are likely the result of multiple sources; some metals may be derived from post-depositional and diagenetic processes, and others are potentially produced from an abundance of decomposing vertebrate carcasses. These new data help to support the inferred depositional environment of the quarry as an ephemeral pond, and represent a significant step in understanding the taphonomy of the bonebed and Late Jurassic paleoecology in this region.
Chemical composition and the potential for proteomic transformation in cancer, hypoxia, and hyperosmotic stress
Authors: Dick Jeffrey M.
Published: June 2017

The changes of protein expression that are monitored in proteomic experiments are a type of biological transformation that also involves changes in chemical composition. Accompanying the myriad molecular-level interactions that underlie any proteomic transformation, there is an overall thermodynamic potential that is sensitive to microenvironmental conditions, including local oxidation and hydration potential. Here, up- and down-expressed proteins identified in 71 comparative proteomics studies were analyzed using the average oxidation state of carbon (ZC) and water demand per residue (${\overline{n}}_{{\mathrm{H}}_{2}\mathrm{O}}$), calculated using elemental abundances and stoichiometric reactions to form proteins from basis species. Experimental lowering of oxygen availability (hypoxia) or water activity (hyperosmotic stress) generally results in decreasedZCor ${\overline{n}}_{{\mathrm{H}}_{2}\mathrm{O}}$ of up-expressed compared to down-expressed proteins. This correspondence of chemical composition with experimental conditions provides evidence for attraction of the proteomes to a low-energy state. An opposite compositional change, toward higher average oxidation or hydration state, is found for proteomic transformations in colorectal and pancreatic cancer, and in two experiments for adipose-derived stem cells. Calculations of chemical affinity were used to estimate the thermodynamic potentials for proteomic transformations as a function of fugacity of O2and activity of H2O, which serve as scales of oxidation and hydration potential. Diagrams summarizing the relative potential for formation of up- and down-expressed proteins have predicted equipotential lines that cluster around particular values of oxygen fugacity and water activity for similar datasets. The changes in chemical composition of proteomes are likely linked with reactions among other cellular molecules. A redox balance calculation indicates that an increase in the lipid to protein ratio in cancer cells by 20% over hypoxic cells would generate a large enough electron sink for oxidation of the cancer proteomes. The datasets and computer code used here are made available in a new R package,canprot.
Unimodal relationship between small-scale barnacle recruitment and the density of pre-existing barnacle adults
Authors: Scrosati Ricardo A. , Ellrich Julius A.
Published: June 2017

Recruitment is a key demographic process for population persistence. This paper focuses on barnacle (Semibalanus balanoides) recruitment. In rocky intertidal habitats from the Gulf of St. Lawrence coast of Nova Scotia (Canada), ice scour is common during the winter. At the onset of intertidal barnacle recruitment in early May (after sea ice has fully melted), mostly only adult barnacles and bare substrate are visible at high elevations in wave-exposed habitats. We conducted a multiannual study to investigate if small-scale barnacle recruitment could be predicted from the density of pre-existing adult barnacles. In a year that exhibited a wide adult density range (ca. 0–130 individuals dm−2), the relationship between adult density and recruit density (scaled to the available area for recruitment, which excluded adult barnacles) was unimodal. In years that exhibited a lower adult density range (ca. 0–40/50 individuals dm−2), the relationship between adult and recruit density was positive and resembled the lower half of the unimodal relationship. Overall, adult barnacle density was able to explain 26–40% of the observed variation in recruit density. The unimodal adult–recruit relationship is consistent with previously documented intraspecific interactions. Between low and intermediate adult densities, the positive nature of the relationship relates to the previously documented fact that settlement-seeking larvae are chemically and visually attracted to adults, which might be important for local population persistence. Between intermediate and high adult densities, where population persistence may be less compromised and the abundant adults may limit recruit growth and survival, the negative nature of the relationship suggests that adult barnacles at increasingly high densities stimulate larvae to settle elsewhere. The unimodal pattern may be especially common on shores with moderate rates of larval supply to the shore, because high rates of larval supply may swamp the coast with settlers, decoupling recruit density from local adult abundance.
No long‐term trends in pCO2 despite increasing organic carbon concentrations in boreal lakes, streams, and rivers
Authors: Nydahl Anna C. , Wallin Marcus B. , Weyhenmeyer Gesa A.
Published: June 2017

Concentrations of dissolved organic carbon (DOC) from terrestrial sources have been increasing in freshwaters across large parts of the boreal region. According to results from large‐scale field and detailed laboratory studies, such a DOC increase could potentially stimulate carbon dioxide (CO2) production, subsequently increasing the partial pressure of CO2 (pCO2) in freshwaters. However, the response of pCO2 to the presently observed long‐term increase in DOC in freshwaters is still unknown. Here we tested whether the commonly found spatial DOC‐pCO2 relationship is also valid on a temporal scale. Analyzing time series of water chemical data from 71 lakes, 30 streams, and 4 river mouths distributed across all of Sweden over a 17 year period, we observed significant DOC concentration increases in 39 lakes, 15 streams, and 4 river mouths. Significant pCO2 increases were, however, only observed in six of these 58 waters, indicating that long‐term DOC increases in Swedish waters are disconnected from temporal pCO2 trends. We suggest that the uncoupling of trends in DOC concentration and pCO2 are a result of increased surface water runoff. When surface water runoff increases, there is likely less CO2 relative to DOC imported from soils into waters due to a changed balance between surface and groundwater flow. Additionally, increased surface water runoff causes faster water flushing through the landscape giving less time for in situ CO2 production in freshwaters. We conclude that pCO2 is presently not following DOC concentration trends, which has important implications for modeling future CO2 emissions from boreal waters.
Nonlinear internal waves and plumes generated in response to sea‐loch outflow, AUV, and time‐lapse photography observations
Authors: Toberman Matthew , Inall Mark , Boyd Tim , Dumount Estelle , Griffiths Colin
Published: June 2017

The tidally modulated outflow of brackish water from a sea loch forms a thin surface layer that propagates into the coastal ocean as a buoyant gravity current, transporting nutrients and sediments, as well as fresh water, heat and momentum. The fresh intrusion both propagates into and generates a strongly stratified environment which supports trains of nonlinear internal waves (NLIWs). NLIWs are shown to propagate ahead of this buoyancy input in response to propagation of the outflow water into the stratified environment generated by the previous release as well as in the opposing direction after the reflection from steep bathymetry. Oblique aerial photographs were taken and photogrammetric rectification led to the identification of the buoyant intrusion and the subsequent generation of NLIWs. An autonomous underwater vehicle (AUV) was deployed on repeated reciprocal transects in order to make simultaneous CTD, ADCP, and microstructure shear measurements of the evolution of these phenomena in conjunction with conventional mooring measurements. AUV‐based temperature and salinity signals of NLIWs of depression were observed together with increased turbulent kinetic energy dissipation rates of over 2 orders of magnitude within and in the wake of the NLIWs. Repeated measurements allow a unique opportunity to investigate the horizontal structure of these phenomena. Simple metric scaling demonstrates that these processes are likely to be feature of many fjordic systems located on the west coast of Scotland but may also play a key role in the assimilation of the outflow from many tidally dominated fjordic systems throughout the world.
Temperature and oxygen dependence of the remineralization of organic matter
Authors: Laufkötter C. , John Jasmin G. , Stock Charles A. , Dunne John P.
Published: June 2017

Accurate representation of the remineralization of sinking organic matter is crucial for reliable projections of the marine carbon cycle. Both water temperature and oxygen concentration are thought to influence remineralization rates, but limited data constraints have caused disagreement concerning the degree of these influences. We analyze a compilation of particulate organic carbon (POC) flux measurements from 19 globally distributed sites. Our results indicate that the attenuation of the flux of particulate organic matter depends on temperature with a Q10 between 1.5 and 2.01, and on oxygen described by a half‐saturation constant between 4 and 12 μmol/L. We assess the impact of the temperature and oxygen dependence in the biogeochemistry model Carbon, Ocean Biogeochemistry, and Lower Trophics, coupled to Geophysical Fluid Dynamics Laboratory's Earth System Model ESM2M. The new remineralization parameterization results in shallower remineralization in the low latitudes but deeper remineralization in the high latitudes, redistributing POC flux toward the poles. It also decreases the volume of the oxygen minimum zones, partly addressing a long‐standing bias in global climate models. Extrapolating temperature‐dependent remineralization rates to the surface (i.e., beyond the depth range of POC flux data) resulted in rapid recycling and excessive surface nutrients. Surface nutrients could be ameliorated by reducing near‐surface rates in a manner consistent with bacterial colonization, suggesting the need for improved remineralization constraints within the euphotic zone. The temperature and oxygen dependence cause an additional 10% decrease in global POC flux at 500 m depth, but no significant change in global POC flux at 2000 m under the RCP8.5 future projection.
Autonomous observing platform CO2 data shed new light on the Southern Ocean carbon cycle
Authors: Olsen Are
Published: June 2017

While the number of surface ocean CO2 partial pressure (pCO2) measurements has soared the recent decades, the Southern Ocean remains undersampled. Williams et al. (2017, https://doi.org/10.1002/2016GB005541) now present pCO2 estimates based on data from pH‐sensor equipped Bio‐Argo floats, which have been measuring in the Southern Ocean since 2014. The authors demonstrate the utility of these data for understanding the carbon cycle in this region, which has a large influence on the distribution of CO2 between the ocean and atmosphere. Biogeochemical sensors deployed on autonomous platforms hold the potential to shape our view of the ocean carbon cycle in the coming decades.
Basin scale variability of active diazotrophs and nitrogen fixation in the North Pacific, from the tropics to the subarctic Bering Sea
Authors: Shiozaki Takuhei , Bombar Deniz , Riemann Lasse , Hashihama Fuminori , Takeda Shigenobu , Yamaguchi Tamaha , Ehama Makoto , Hamasaki Koji , Furuya Ken
Published: June 2017

Nitrogen‐fixing microorganisms (diazotrophs) provide biologically available nitrogen to plankton communities and thereby greatly influence the productivity in many marine regions. Various cyanobacterial groups have traditionally been considered the major oceanic diazotrophs, but later noncyanobacterial and presumably heterotrophic diazotrophs were also found to be widespread and potentially important in nitrogen fixation. However, the distribution and activity of different diazotroph groups is still poorly constrained for most oceanic ecosystems. Here we examined diazotroph community structure and activity along a 7500 km south‐north transect between the central equatorial Pacific and the Bering Sea. Nitrogen fixation contributed up to 84% of new production in the upper waters of the subtropical gyre, where the diazotroph community included the gammaproteobacterium γ‐24774A11 and highly active cyanobacterial phylotypes (>50% of total nifH transcript abundance). Nitrogen fixation was sometimes detectable down to 150 m depth and extended horizontally to the edge of the gyre at around 35°N. Nitrogen fixation was even detected far north on the Bering Sea shelf. In the Alaskan Coastal Waters on the Bering Sea shelf, low nitrate together with high dissolved iron concentrations seemed to foster diazotroph growth, including a prominent role of UCYN‐A2, which was abundant near the surface (1.2×105 nifH gene copies L−1). Our study provides evidence for nitrogen fixation in the Bering Sea and suggests a clear contrast in the composition of diazotrophs between the tropical/subtropical gyre and the separate waters in the cold northern regions of the North Pacific.
CMIP5 models' shortwave cloud radiative response and climate sensitivity linked to the climatological Hadley cell extent
Authors: Lipat Bernard R. , Tselioudis George , Grise Kevin M. , Polvani Lorenzo M.
Published: June 2017

This study analyzes Coupled Model Intercomparison Project phase 5 (CMIP5) model output to examine the covariability of interannual Southern Hemisphere Hadley cell (HC) edge latitude shifts and shortwave cloud radiative effect (SWCRE). In control climate runs, during years when the HC edge is anomalously poleward, most models substantially reduce the shortwave radiation reflected by clouds in the lower midlatitude region (LML; ∼28°S–∼48°S), although no such reduction is seen in observations. These biases in HC‐SWCRE covariability are linked to biases in the climatological HC extent. Notably, models with excessively equatorward climatological HC extents have weaker climatological LML subsidence and exhibit larger increases in LML subsidence with poleward HC edge expansion. This behavior, based on control climate interannual variability, has important implications for the CO2‐forced model response. In 4×CO2‐forced runs, models with excessively equatorward climatological HC extents produce stronger SW cloud radiative warming in the LML region and tend to have larger climate sensitivity values than models with more realistic climatological HC extents.
Preconditioning of Antarctic maximum sea ice extent by upper ocean stratification on a seasonal timescale
Authors: Su Zhan
Published: June 2017

This study uses an observationally constrained and dynamically consistent ocean and sea ice state estimate. The author presents a remarkable agreement between the location of the edge of Antarctic maximum sea ice extent, reached in September, and the narrow transition band for the upper ocean (0–100 m depths) stratification, as early as April to June. To the south of this edge, the upper ocean has high stratification, which forbids convective fluxes to cross through; consequently, the ocean heat loss to the atmosphere is an efficient way to cool the surface ocean to the freezing point during April to September. To the north, the upper ocean has low stratification such that the ocean heat loss to the atmosphere is not efficient to cool the upper ocean. The upper ocean is instead cooled mainly through mixing with the colder inflow carried by northward Ekman transport but cannot reach the freezing point due to the nature of mixing. Therefore, upper ocean stratification, dominated by salinity here, provides an important constraint on the northward expansion of Antarctic sea ice to its maximum.
Van Allen Probes observations of whistler‐mode chorus with long‐lived oscillating tones
Authors: Gao Zhonglei , Su Zhenpeng , Chen Lunjin , Zheng Huinan , Wang Yuming , Wang Shui
Published: June 2017

Whistler‐mode chorus plays an important role in the radiation belt electron dynamics. In the frequency‐time spectrogram, chorus often appears as a hiss‐like band and/or a series of short‐lived (up to ∼1 s) discrete elements. Here we present some rarely reported chorus emissions with long‐lived (up to 25 s) oscillating tones observed by the Van Allen Probes in the dayside (MLT ∼9–14) midlatitude (|MLAT|>15°) region. An oscillating tone can behave either regularly or irregularly and can even transform into a nearly constant tone (with a relatively narrow frequency sweep range). We suggest that these highly coherent oscillating tones were generated naturally rather than being related to some artificial VLF transmitters. Possible scenarios for the generation of the oscillating tone chorus are as follows: (1) being nonlinearly triggered by the accompanying hiss‐like bands or (2) being caused by the modulation of the wave source. The details of the generation and evolution of such a long‐lived oscillating tone chorus need to be investigated both theoretically and experimentally in the future.
Uncertain soil moisture feedbacks in model projections of Sahel precipitation
Authors: Berg Alexis , Lintner Benjamin R. , Findell Kirsten , Giannini Alessandra
Published: June 2017

Given the uncertainties in climate model projections of Sahel precipitation, at the northern edge of the West African Monsoon, understanding the factors governing projected precipitation changes in this semiarid region is crucial. This study investigates how long‐term soil moisture changes projected under climate change may feedback on projected changes of Sahel rainfall, using simulations with and without soil moisture change from five climate models participating in the Global Land Atmosphere Coupling Experiment‐Coupled Model Intercomparison Project phase 5 experiment. In four out of five models analyzed, soil moisture feedbacks significantly influence the projected West African precipitation response to warming; however, the sign of these feedbacks differs across the models. These results demonstrate that reducing uncertainties across model projections of the West African Monsoon requires, among other factors, improved mechanistic understanding and constraint of simulated land‐atmosphere feedbacks, even at the large spatial scales considered here.
WINDII airglow observations of wave superposition and the possible association with historical “bright nights”
Authors: Shepherd G. G. , Cho Y.‐M.
Published: June 2017

Longitudinal variations of airglow emission rate are prominent in all midlatitude nighttime O(1S) lower thermospheric data obtained with the Wind Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite (UARS). The pattern generally appears as a combination of zonal waves 1, 2, 3, and 4 whose phases propagate at different rates. Sudden localized enhancements of 2 to 4 days duration are sometimes evident, reaching vertically integrated emission rates of 400 R, a factor of 10 higher than minimum values for the same day. These are found to occur when the four wave components come into the same phase at one longitude. It is shown that these highly localized longitudinal maxima are consistent with the historical phenomena known as “bright nights” in which the surroundings of human dark night observers were seen to be illuminated by this enhanced airglow.
Pronounced differences between observed and CMIP5‐simulated multidecadal climate variability in the twentieth century
Authors: Kravtsov Sergey
Published: June 2017

Identification and dynamical attribution of multidecadal climate undulations to either variations in external forcings or to internal sources is one of the most important topics of modern climate science, especially in conjunction with the issue of human‐induced global warming. Here we utilize ensembles of twentieth century climate simulations to isolate the forced signal and residual internal variability in a network of observed and modeled climate indices. The observed internal variability so estimated exhibits a pronounced multidecadal mode with a distinctive spatiotemporal signature, which is altogether absent in model simulations. This single mode explains a major fraction of model‐data differences over the entire climate index network considered; it may reflect either biases in the models' forced response or models' lack of requisite internal dynamics, or a combination of both.
Influences of drizzle on stratocumulus cloudiness and organization
Authors: Zhou Xiaoli , Heus Thijs , Kollias Pavlos
Published: June 2017

Large‐eddy simulations are used to study the influence of drizzle on stratocumulus organization, based on measurements made as part of the Second Dynamics and Chemistry of the Marine Stratocumulus field study‐II. Cloud droplet number concentration (Nc) is prescribed and considered as the proxy for different aerosol loadings. Our study shows that the amount of cloudiness does not decrease linearly with precipitation rate. An Nc threshold is observed below which the removal of cloud water via precipitation efficiently reduces cloud depth, allowing evaporation to become efficient and quickly remove the remaining thin clouds, facilitating a fast transition from closed cells to open cells. Using Fourier analysis, stratocumulus length scales are found to increase with drizzle rates. Raindrop evaporation below 300 m lowers the cloud bases and amplifies moisture variances in the subcloud layer, while it does not alter the horizontal scales in the cloud layer, suggesting that moist cold pool dynamic forcings are not essential for mesoscale organization of stratocumulus. The cloud scales are greatly increased when the boundary layer is too deep to maintain well mixed.
Tree ring δ18O reveals no long‐term change of atmospheric water demand since 1800 in the northern Great Hinggan Mountains, China
Authors: Liu Xiaohong , Zhang Xuanwen , Zhao Liangju , Xu Guobao , Wang Lixin , Sun Weizhen , Zhang Qiuliang , Wang Wenzhi , Zeng Xiaomin , Wu Guoju
Published: June 2017

Global warming will significantly increase transpirational water demand, which could dramatically affect plant physiology and carbon and water budgets. Tree ring δ18O is a potential index of the leaf‐to‐air vapor‐pressure deficit (VPD) and therefore has great potential for long‐term climatic reconstruction. Here we developed δ18O chronologies of two dominant native trees, Dahurian larch (Larix gmelinii Rupr.) and Mongolian pine (Pinus sylvestris var. mongolica), from a permafrost region in the Great Hinggan Mountains of northeastern China. We found that the July–August VPD and relative humidity were the dominant factors that controlled tree ring δ18O in the study region, indicating strong regulation of stomatal conductance. Based on the larch and pine tree ring δ18O chronologies, we developed a reliable summer (July–August) VPD reconstruction since 1800. Warming growing season temperatures increase transpiration and enrich cellulose 18O, but precipitation seemed to be the most important influence on VPD changes in this cold region. Periods with stronger transpirational demand occurred around the 1850s, from 1914 to 1925, and from 2005 to 2010. However, we found no overall long‐term increasing or decreasing trends for VPD since 1800, suggesting that despite the increasing temperatures and thawing permafrost throughout the region, forest transpirational demand has not increased significantly during the past two centuries. Under current climatic conditions, VPD did not limit growth of larch and pine, even during extremely drought years. Our findings will support more realistic evaluations and reliable predictions of the potential influences of ongoing climatic change on carbon and water cycles and on forest dynamics in permafrost regions.
Assessment of volumetric absorbed dose for mobile fluoroscopic 3D image acquisition
Authors: Leon Stephanie
Published: June 2017

Mobile fluoroscopy (c‐arm) units offering 3D image reconstruction are becoming more common in surgical settings. Although these images are “CT‐like” and sometimes replace the postoperative CT, the acquisition is technically very different from a traditional CT acquisition. Dose assessment is complicated by a large beam width, automatic exposure rate control, and a rotation of less than 360°. The purpose of this work was to explore the impact of these factors on the volumetric dose calculation and to provide practical recommendations for clinical physicists assessing dose from these units using commonly available equipment. CTDIW was calculated using the IAEA method for dosimetry of wide beams and compared to scans of the 32‐cm CTDI phantom using the full beam width and a 20‐mm collimated beam width. The impact of the partial rotation on the CTDIW calculation was assessed by acquiring measurements at four and twelve positions on the phantom periphery. For the system tested, the CTDIW was calculated to be 16.1 mGy using the IAEA method with default clinical protocol. Results showed that measuring CTDIW with the full beam width or a collimated beam width alone resulted in CTDI values of 19.0 mGy and 19.5 mGy, respectively. Using four peripheral measurements instead of 12 resulted in a difference of 4% for a collimated beam and 6% for an open beam. Variations in positioning on the order of a few centimeters resulted in a variation of only 4% with an open beam. The excellent reproducibility of the measurements using the full beam width suggests that this simple method is adequate for year‐to‐year comparisons. In contrast, the IAEA method is difficult to employ, particularly with 180° acquisitions. Use of peripheral measurements in excess of the usual four is time‐consuming and not necessary for most applications obtained with the geometry specific to this system.
Technical Note: Monte Carlo calculations of the AAPM TG‐43 brachytherapy dosimetry parameters for a new titanium‐encapsulated Yb‐169 source
Authors: Reynoso Francisco J. , Munro III John J. , Cho Sang Hyun
Published: June 2017

Due to a number of distinct advantages resulting from the relatively low energy gamma ray spectrum of Yb‐169, various designs of Yb‐169 sources have been developed over the years for brachytherapy applications. Lately, Yb‐169 has also been suggested as an effective and practical radioisotope option for a novel radiation treatment approach often known as gold nanoparticle‐aided radiation therapy (GNRT). In a recently published study, the current investigators used the Monte Carlo N‐Particle Version 5 (MCNP5) code to design a novel titanium‐encapsulated Yb‐169 source optimized for GNRT applications. In this study, the original MC source model was modified to accurately match the specifications of the manufactured Yb‐169 source. The modified MC model was then used to obtain a complete set of the AAPM TG‐43 parameters for the new titanium‐encapsulated Yb‐169 source. The MC‐calculated dose rate constant for this titanium‐encapsulated Yb‐169 source was 1.19 ± 0.03 , indicating no significant change from the values reported for stainless steel‐encapsulated Yb‐169 sources. The source anisotropy and radial dose function for the new source were also found similar to those reported for the stainless steel‐encapsulated Yb‐169 sources. The current results suggest that the use of titanium, instead of stainless steel, to encapsulate the Yb‐169 core would not lead to any major change in the dosimetric characteristics of the Yb‐169 source. The results also show that the titanium encapsulation of the Yb‐169 source could be accomplished while meeting the design goals as described in the current investigators’ published MC optimization study for GNRT applications.
Effect of VERO pan‐tilt motion on the dose distribution
Authors: Prasetio Heru , Yohannes Indra , Bert Christoph
Published: June 2017

Tumor tracking is an option for intra‐fractional motion management in radiotherapy. The VERO gimbal tracking system creates a unique beam geometry and understanding the effect of the gimbal motion in terms of dose distribution is important to assess the dose deviation from the reference conditions. Beam profiles, output factors (OF) and percentage depth doses (PDD) were measured and evaluated to investigate this effect. In order to find regions affected by the pan‐tilt motion, synthesized 2D dose distributions were generated. An evaluation of the 2D dose distribution with the reference position was done using dose difference criteria 1%–4%. The OF and point dose at central axis were measured and compared with the reference position. Furthermore, the PDDs were measured using a special monitoring approach to filtering inaccurate points during the acquisition. Beam profiles evaluation showed that the effect of pan‐tilt at inline direction was stronger than at the crossline direction. The maximum average deviation of the full width half maximum (FWHM), flatness, symmetry, penumbra left and right were 0.39 ± 0.25 mm, 0.62 ± 0.50%, 0.76 ± 0.59%, 0.22 ± 0.16 mm, and 0.19 ± 0.15 mm respectively. The ÔF and the measured dose average deviation were <0.5%. The mechanical accuracies during the PDD measurements were 0.28 ± 0.09 mm and 0.21 ± 0.09 mm for pan and tilt and pan or tilt position. The PDD average deviations were 0.58 ± 0.26 % and 0.54 ± 0.25 % for pan‐or‐tilt and pan‐and‐tilt position respectively. All the results showed that the deviation at pan and tilt position are higher than pan or tilt. The most influences were observed for the penumbra region and the shift of radiation beam path.
Does liver resection/transplantation affect respiratory induced liver motion in patients with hepatocellular carcinoma?
Authors: Hu Yong , Zhou Yong‐Kang , Chen Yi‐Xing , Ye Lu‐Xi , Zeng Zhao‐Chong
Published: June 2017

The purpose of this study was to evaluate the changes in magnitude of three‐dimensional (3D) liver motion after liver resection/transplantation in patients with hepatocellular carcinoma (HCC) using four‐dimensional (4D)‐computed tomography (CT) images. From January 2012 to April 2016, 74 HCC patients underwent 4D‐CT scans under a free‐breathing state to assess respiratory liver motion. Of the 74 patients, 40 did not have a liver resection/transplantation (Group A), 34 with liver resection/transplantation. 15 underwent major or minor resection in the right liver lobe (Group B), 14 underwent major or minor resection in the left liver lobe (Group C), and five underwent liver transplantation (Group D). The 4D‐CT images were sorted into 10 image series according to the respiratory phase from the end inspiration to the end expiration, and then transferred to treatment planning software. All liver contours were drawn by a single physician and confirmed by a second. Liver relative coordinates were automatically generated to calculate liver respiratory motion in different axial directions and compiled into a single composite image. Differences in respiratory liver motion were assessed using one‐way ANOVA. The average liver respiratory motion in the cranial‐caudal direction and 3D magnitude were 10.46 ± 2.78 mm (range, 5.60–18.80 mm) and 11.74 ± 2.65 mm (range, 7.45–20.79 mm) for patients without liver resection/transplantation, and 7.74 ± 2.79 mm (range, 2.20–12.90 mm) and 9.07 ± 2.38 mm (range, 4.79–14.08 mm) for posthepatectomy/post‐transplant patients respectively. There were significant differences between Group A and B, Group A and C, Group A and D. However, there were no significant differences among Group B, C, and D. Liver resection/transplantation greatly affected respiratory‐induced liver motion in patients with HCC. We, therefore, recommend discriminatory internal target volume (ITV) determination for patients with or without liver resection/transplantation undergoing external radiotherapy for hepatic tumors while respiratory motion management is unavailable.
Orientational Coupling Locally Orchestrates a Cell Migration Pattern for Re‐Epithelialization
Authors: Hu Benhui , Leow Wan Ru , Amini Shahrouz , Nai Brenda , Zhang Xiaoqian , Liu Zhiyuan , Cai Pingqiang , Li Zhuyun , Wu Yun‐Long , Miserez Ali , Lim Chwee Teck , Chen Xiaodong
Published: June 2017

Re‐epithelialization by collective migration of epithelial cells over a heterogeneous environment to restore tissue integrity and functions is critical for development and regeneration. Here, it is reported that the spatial organization of adjacent adherent paths within sparsely distributed extracellular matrix (ECM) has a significant impact on the orientational coupling between cell polarization and collective cell migration. This coupling effect determines the migration pattern for human keratinocytes to regain their cohesion, which impacts the occupancy of epithelial bridge and the migration velocity in wound repair. Statistical studies suggest the converging organization of ECM, in which adjacent paths become closer to each other and finally converge to a junctional point, facilitating collective cell migration mostly within variable ECM organization, as the polarization of the advancing cell sheet is remodeled to align along the direction of cell migration. The findings may help to design implantable ECM to optimize efficient skin regeneration.
Confining the Nucleation of Pt to In Situ Form (Pt‐Enriched Cage)@CeO2 Core@Shell Nanostructure as Excellent Catalysts for Hydrogenation Reactions
Authors: Song Shuyan , Liu Xianchun , Li Junqi , Pan Jing , Wang Fan , Xing Yan , Wang Xiao , Liu Xiaogang , Zhang Hongjie
Published: June 2017

Ultrathin (Pt‐enriched cage)@CeO2 core@shell nanostructures are successfully fabricated via a facile hard‐template method. It is found that the usage of Pd@Ag@CeO2 bi‐metallic core@shell nanostructure as the hard template plays an important role in avoiding the independent nucleation of Pt metal during the galvanic replacement process between K2PtCl4 and Ag components. This unique core@shell samples show extraordinary activity and selectivity for the cinnamaldehyde hydrogenation reaction. It can achieve over 95% conversion with 87% selectivity of hydrocinnamaldehyde in 5 h under 1 atm H2 pressure. It is considered that such high catalytic performance could be attributed to the densely CeO2‐coated core@shell hybrid form as well as the ultrathin nature of the Pt‐enriched cage.
Homogeneous 2D MoTe2 p–n Junctions and CMOS Inverters formed by Atomic‐Layer‐Deposition‐Induced Doping
Authors: Lim June Yeong , Pezeshki Atiye , Oh Sehoon , Kim Jin Sung , Lee Young Tack , Yu Sanghyuck , Hwang Do Kyung , Lee Gwan‐Hyoung , Choi Hyoung Joon , Im Seongil
Published: June 2017

Recently, α‐MoTe2, a 2D transition‐metal dichalcogenide (TMD), has shown outstanding properties, aiming at future electronic devices. Such TMD structures without surface dangling bonds make the 2D α‐MoTe2 a more favorable candidate than conventional 3D Si on the scale of a few nanometers. The bandgap of thin α‐MoTe2 appears close to that of Si and is quite smaller than those of other typical TMD semiconductors. Even though there have been a few attempts to control the charge‐carrier polarity of MoTe2, functional devices such as p–n junction or complementary metal–oxide–semiconductor (CMOS) inverters have not been reported. Here, we demonstrate a 2D CMOS inverter and p–n junction diode in a single α‐MoTe2 nanosheet by a straightforward selective doping technique. In a single α‐MoTe2 flake, an initially p‐doped channel is selectively converted to an n‐doped region with high electron mobility of 18 cm2 V−1 s−1 by atomic‐layer‐deposition‐induced H‐doping. The ultrathin CMOS inverter exhibits a high DC voltage gain of 29, an AC gain of 18 at 1 kHz, and a low static power consumption of a few nanowatts. The results show a great potential of α‐MoTe2 for future electronic devices based on 2D semiconducting materials.
Connectivity Predicts deep brain stimulation outcome in Parkinson disease
Authors: Horn Andreas , Reich Martin , Vorwerk Johannes , Li Ningfei , Wenzel Gregor , Fang Qianqian , Schmitz‐Hübsch Tanja , Nickl Robert , Kupsch Andreas , Volkmann Jens , Kühn Andrea A. , Fox Michael D.
Published: June 2017

Objective

The benefit of deep brain stimulation (DBS) for Parkinson disease (PD) may depend on connectivity between the stimulation site and other brain regions, but which regions and whether connectivity can predict outcome in patients remain unknown. Here, we identify the structural and functional connectivity profile of effective DBS to the subthalamic nucleus (STN) and test its ability to predict outcome in an independent cohort.

Methods

A training dataset of 51 PD patients with STN DBS was combined with publicly available human connectome data (diffusion tractography and resting state functional connectivity) to identify connections reliably associated with clinical improvement (motor score of the Unified Parkinson Disease Rating Scale [UPDRS]). This connectivity profile was then used to predict outcome in an independent cohort of 44 patients from a different center.

Results

In the training dataset, connectivity between the DBS electrode and a distributed network of brain regions correlated with clinical response including structural connectivity to supplementary motor area and functional anticorrelation to primary motor cortex (p < 0.001). This same connectivity profile predicted response in an independent patient cohort (p < 0.01). Structural and functional connectivity were independent predictors of clinical improvement (p < 0.001) and estimated response in individual patients with an average error of 15% UPDRS improvement. Results were similar using connectome data from normal subjects or a connectome age, sex, and disease matched to our DBS patients.

Interpretation

Effective STN DBS for PD is associated with a specific connectivity profile that can predict clinical outcome across independent cohorts. This prediction does not require specialized imaging in PD patients themselves. Ann Neurol 2017;82:67–78
A Dysprosium Metallocene Single‐Molecule Magnet Functioning at the Axial Limit
Authors: Guo Fu‐Sheng , Day Benjamin M. , Chen Yan‐Cong , Tong Ming‐Liang , Mansikkamäki Akseli , Layfield Richard A.
Published: June 2017

Abstraction of a chloride ligand from the dysprosium metallocene [(Cpttt)2DyCl] (1Dy Cpttt=1,2,4‐tri(tert‐butyl)cyclopentadienide) by the triethylsilylium cation produces the first base‐free rare‐earth metallocenium cation [(Cpttt)2Dy]+ (2Dy) as a salt of the non‐coordinating [B(C6F5)4]− anion. Magnetic measurements reveal that [2Dy][B(C6F5)4] is an SMM with a record anisotropy barrier up to 1277 cm−1 (1837 K) in zero field and a record magnetic blocking temperature of 60 K, including hysteresis with coercivity. The exceptional magnetic axiality of 2Dy is further highlighted by computational studies, which reveal this system to be the first lanthanide SMM in which all low‐lying Kramers doublets correspond to a well‐defined MJ value, with no significant mixing even in the higher doublets.
Noncovalent Immobilization of Molecular Electrocatalysts for Chemical Synthesis: Efficient Electrochemical Alcohol Oxidation with a Pyrene–TEMPO Conjugate
Authors: Das Amit , Stahl Shannon S.
Published: June 2017

Electrocatalytic methods for organic synthesis could offer sustainable alternatives to traditional redox reactions, but strategies are needed to enhance the performance of molecular catalysts designed for this purpose. The synthesis of a pyrene‐tethered TEMPO derivative (TEMPO=2,2,6,6‐tetramethylpiperidinyl‐N‐oxyl) is described, which undergoes facile in situ noncovalent immobilization onto a carbon cloth electrode. Cyclic voltammetry and controlled potential electrolysis studies demonstrate that the immobilized catalyst exhibits much higher activity relative to 4‐acetamido–TEMPO, an electronically similar homogeneous catalyst. In preparative electrolysis experiments with a series of alcohol substrates and the immobilized catalyst, turnover numbers and frequencies approach 2 000 and 4 000 h−1, respectively. The synthetic utility of the method is further demonstrated in the oxidation of a sterically hindered hydroxymethylpyrimidine precursor to the blockbuster drug, rosuvastatin.
Cobalt ferrite encapsulated in a zwitterionic chitosan derived shell: An efficient nano‐magnetic catalyst for three‐component syntheses of pyrano[3,2‐c]quinolines and spiro‐oxindoles
Authors: Asghari‐Haji Fatereh , Rad‐Moghadam Kurosh , Mahmoodi Nosrat O. , Tonekaboni Tayyebeh , Rahimi Najmeh
Published: June 2017

A nano‐magnetic core‐shell composite fabricated of a unique zwitterionic chitosan‐derived coating and cobalt ferrite core was found to be a green and reusable heterogeneous catalyst for efficient synthesis of pyrano[3,2‐c]quinoline and spiro‐oxindole derivatives in high to excellent yields. Due to having negative charges at its outermost layer and a high magnetization, the catalyst is finely dispersed in ethanol and can be easily separated from reaction mixtures by using a simple external magnet. It is reasonably stable as can be reused several times without appreciable loss of catalytic activity.