bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strategies for radiation exposure‐sparing in fluoroscopically guided invasive cardiovascular procedures
Authors: Fiorilli Paul N. , Kobayashi Taisei , Giri Jay , Hirshfeld John W. 
Published: April 2019

AbstractBackgroundMinimizing radiation exposure during x‐ray fluoroscopically guided procedures is critical to patients and to medical personnel. Tableside adjustment of x‐ray image acquisition parameters can vary the fluoroscopic radiation exposure rate.ObjectivesTo determine the impact of adjusting four tableside controllable image acquisition parameters on x‐ray fluoroscopic radiation exposure rate.MethodsWe made fluoroscopic exposures of a standard radiologic phantom to measure radiation exposure rates as kerma•area product per second of exposure and milligray per x‐ray pulse under all possible combinations of detector zoom mode, collimated image field size, fluoroscopy dose mode, and fluoroscopy pulse frequency.ResultsKerma•area product per second was linearly proportional to pulse frequency. Selecting larger detector zoom modes, smaller collimated image field sizes and low dose fluoroscopy mode each decreased exposure rate. We found a > 20‐fold variation in dose rates over the range of acquisition parameter combinations.ConclusionsSelecting the most appropriate fluoroscopy acquisition parameters enables physician operators to adjust radiation exposure rates over a large range. Judicious selection of acquisition parameters can reduce patient and medical personnel radiation exposure by as much as 95% compared to “standard” fluoroscopy protocol settings.
One‐Step Pyrolysis to Synthesize Non‐Graphitic Nitrogen‐Doped 2D Ultrathin Carbon Nanosheets and Their Application in Supercapacitors
Authors: Guo Wen , Zhou Yansong , Pang Lei , Chen Zhen , Dong Yahao , Bi Jiajun , Ming Shujun , Li Tao 
Published: April 2019

AbstractNon‐graphitic nitrogen plays a significant role in determining the electrochemical performance of carbon materials in the field of energy storage. However, the synthesis of carbon materials with a high level of non‐graphitic nitrogen doping is still a great challenge. In this paper, a facile one‐step pyrolysis approach was developed to synthesize 2D carbon nanosheets with a ultrahigh non‐graphitic nitrogen content. Through an ingenious design, g‐C3N4 and NH3, both generated during the pyrolysis process, play major roles in the generation of the non‐graphitic nitrogen‐doped carbon nanosheets. The intermediate g‐C3N4 acts as both a self‐sacrificial template and a nitrogen source, whereas NH3 offers a nitrogen‐enriched chemical atmosphere. Benefiting from the high pyridinic‐nitrogen content of the maternal g‐C3N4 and the reductive atmosphere of NH3, the as‐prepared carbon nanosheets exhibit a strikingly high non‐graphitic nitrogen content (up to 17.36 wt.%); also, thanks to the g‐C3N4 self‐sacrificial template, the as‐synthesized carbon nanosheets are 2D with an ultrathin thickness (3–4 nm) and a porous structure. These novel features make the as‐prepared carbon nanosheets an excellent supercapacitor electrode material in terms of superior specific capacitance (316.8 F g−1 at 1 A g−1), excellent cycling stability (without obvious capacitance loss after 10 000 cycles at 10 A g−1) and high energy density (up to 10.56 Wh kg−1 at a power density of 500 W kg−1). This work provides a new idea to prepare non‐graphitic nitrogen enriched carbon materials.
Spatial Mallows model averaging for geostatistical models
Authors: Liao Jun , Zou Guohua , Gao Yan 
Published: April 2019

AbstractImportant progress has been made with model averaging methods over the past decades. For spatial data, however, the idea of model averaging has not been applied well. This article studies model averaging methods for the spatial geostatistical linear model. A spatial Mallows criterion is developed to choose weights for the model averaging estimator. The resulting estimator can achieve asymptotic optimality in terms of L2 loss. Simulation experiments reveal that our proposed estimator is superior to the model averaging estimator by the Mallows criterion developed for ordinary linear models [Hansen, 2007] and the model selection estimator using the corrected Akaike's information criterion, developed for geostatistical linear models [Hoeting et al., 2006]. The Canadian Journal of Statistics 47: 336–351; 2019 © 2019 Statistical Society of Canada
Katanin catalyzes microtubule depolymerization independently of tubulin C‐terminal tails
Authors: Belonogov Liudmila , Bailey Megan E. , Tyler Madison A. , Kazemi Arianna , Ross Jennifer L. 
Published: April 2019

AbstractMicrotubule network remodeling is an essential process for cell development, maintenance, cell division, and motility. Microtubule‐severing enzymes are key players in the remodeling of the microtubule network; however, there are still open questions about their fundamental biochemical and biophysical mechanisms. Here, we explored the ability of the microtubule‐severing enzyme katanin to depolymerize stabilized microtubules. Interestingly, we found that the tubulin C‐terminal tail (CTT), which is required for severing, is not required for katanin‐catalyzed depolymerization. We also found that the depolymerization of microtubules lacking the CTT does not require ATP or katanin's ATPase activity, although the ATP turnover enhanced depolymerization. We also observed that the depolymerization rate depended on the katanin concentration and was best described by a hyperbolic function. Finally, we demonstrate that katanin can bind to filaments that lack the CTT, contrary to previous reports. The results of our work indicate that microtubule depolymerization likely involves a mechanism in which binding, but not enzymatic activity, is required for tubulin dimer removal from the filament ends.
Characterization of Disulfide Bond Rebridged Fab–Drug Conjugates Prepared Using a Dual Maleimide Pyrrolobenzodiazepine Cytotoxic Payload
Authors: Ruddle Ben T. , Fleming Ryan , Wu Herren , Gao Changshou , Dimasi Nazzareno 
Published: April 2019

AbstractWe describe the characterization of antigen binding fragments (Fab)–drug conjugates prepared using a dual maleimide pyrrolobenzodiazepine dimer cytotoxic payload (SG3710). Pyrrolobenzodiazepine dimers, which are DNA cross‐linkers, are a class of payloads used in antibody–drug conjugates (ADCs). SG3710 was designed to rebridge two adjacent cysteines, such as those that form the canonical interchain disulfide bond between the light and heavy chain in Fab fragments. The rebridging generated homogenous Fab conjugates, with a drug‐to‐Fab ratio of one, as demonstrated by the preparation of rebridged Fabs derived from the anti‐HER2 trastuzumab antibody and from a negative control antibody both prepared using recombinant expression and papain digestion. The resulting anti‐HER2 trastuzumab Fab‐rebridged conjugate retained antigen binding, was stable in rat serum, and demonstrated potent and antigen‐dependent cancer cell‐killing ability. Disulfide rebridging with SG3710 is a generic approach to prepare Fab–pyrrolobenzodiazepine dimer conjugates, which does not require the Fabs to be engineered for conjugation. Thus, SG3710 offers a flexible and straightforward platform for the controlled assembly of pyrrolobenzodiazepine dimer conjugates from any Fab for oncology applications.
Autophagy inhibition overcomes sorafenib resistance in S45F‐mutated desmoid tumors
Authors: Braggio Danielle , Koller David , Jin Feng , Siva Nanda , Zewdu Abeba , Lopez Gonzalo , Batte Kara , Casadei Lucia , Welliver Meng , Strohecker Anne M. , Lev Dina , Pollock Raphael E. 
Published: April 2019

BackgroundDesmoid tumors (DTs) are rare and understudied fibroblastic lesions that are frequently recurrent and locally invasive. DT patients often experience chronic pain, organ dysfunction, decrease in quality of life, and even death.MethodsSorafenib has emerged as a promising therapeutic strategy, which has led to the first randomized phase 3 clinical trial devoted to DTs. Concurrently, we conducted a comprehensive analysis of sorafenib efficacy in a large panel of desmoid cell strains to probe for response mechanism.ResultsWe found distinctive groups of higher‐ and lower‐responder cells. Clustering the lower‐responder group, we observed that CTNNB1 mutation was determinant of outcome. Our results revealed that a lower dose of sorafenib was able to inhibit cell viability, migration, and invasion of wild‐type and T41A‐mutated DTs. Apoptosis induction was observed in those cells after treatment with sorafenib. On the other hand, the lower dose of sorafenib was not able to inhibit cell viability, migration, or invasion or to induce apoptosis in the S45F‐mutated DTs. The investigation of autophagy showed the dependency of S45F‐mutated DTs on this pathway as a part of cell survival mechanism. Significantly, when autophagy was inhibited genetically or pharmacologically in the S45F mutant cell strains, sensitivity to sorafenib was restored.ConclusionsOur findings suggest that the response to sorafenib differs when comparing S45F‐mutated DTs and T41A‐mutated or wild‐type DTs. Furthermore, the combination of hydroxychloroquine and sorafenib enhances the antiproliferative and proapoptotic effects in S45F‐mutated DT cells, suggesting that profiling β‐catenin status could guide clinical management of desmoid patients who are considering sorafenib treatment.
Cholecystokinin immunoreactive neurons in the basolateral amygdala of the rhesus monkey (Macaca mulatta)
Authors: McDonald Alexander J. , Mascagni Franco 
Published: April 2019

AbstractSeveral distinct subpopulations of interneurons (INs) in the amygdalar basolateral nuclear complex (BNC) of the rat can be recognized on the basis of their expression of calcium‐binding proteins and neuropeptides, including parvalbumin (PV), somatostatin (SOM), calretinin (CR), and cholecystokinin (CCK). In the rat BNC CCK is expressed in two separate IN subpopulations, termed large (CCKL) and small (CCKS). These subpopulations exhibit distinct connections indicative of discrete functional roles in the circuitry of the BNC. Although there have been several studies of PV+, SOM+, and CR+ INs in the primate BNC, there is almost no information regarding CCK+ INs in these species. Therefore, in the present study the distribution and morphology of CCK+ INs and their axon terminals in the BNC of the monkey was investigated. CCK immunoreactivity in the BNC was observed in somata and proximal dendrites of nonpyramidal neurons, as well as in axon terminals. A moderate density of CCK+ INs was found in all nuclei of the BNC. CCK+ INs in the BNC were morphologically heterogeneous, with both small and large varieties observed. All CCK+ somata gave rise to 2–4 dendrites that branched sparingly and were aspiny. CCK+ axon terminals in the BNC were found both in the neuropil and forming pericellular baskets contacting somata of pyramidal cells. In addition, many CCK+ neurons were contacted by multiple CCK+ terminals, indicative of the existence of a CCK interneuronal network. These data indicate that the morphology of CCK+ INs in the monkey is very similar to that of the rat.
Image‐Based Flow Cytometry and Angle‐Resolved Light Scattering to Define the Sickling Process
Authors: Goktas Polat , Sukharevsky Ilya O. , Larkin Sandra , Kuypers Frans A. , Yalcin Ozlem , Altintas Ayhan 
Published: April 2019

AbstractRed blood cells (RBCs) from sickle cell patients exposed to a low oxygen tension reveal highly heterogeneous cell morphologies due to the polymerization of sickle hemoglobin (HbS). We show that angle‐resolved light scattering approach with the use of image‐based flow cytometry provides reliable quantitative data to define the change in morphology of large populations of RBCs from sickle cell patients when the cells are exposed for different times to low oxygen. We characterize the RBC morphological profile by means of a set of morphological and physical parameters, which includes cell shape, size, and orientation. These parameters define the cell as discocyte, sickle, elongated, as well as irregularly or abnormal RBC shaped cells, including echinocytes, holly‐leaf, and granular structures. In contrast to microscopy, quick assessment of large numbers of cells provides statistically relevant information of the dynamic process of RBC sickling in time. The use of this approach facilitates the understanding of the processes that define the propensity of sickle blood samples to change their shape, and the ensuing vaso‐occlusive events in the circulation of the patients. Moreover, it assists in the evaluation of treatments that include the use of anti‐sickling agents, gene therapy‐based hemoglobin modifications, as well as other approaches to improve the quality of life of sickle cell patients. © 2019 International Society for Advancement of Cytometry
Filling in the phylogenetic gaps: Induction, migration, and differentiation of neural crest cells in a squamate reptile, the veiled chameleon (Chamaeleo calyptratus)
Authors: Diaz Raul E. , Shylo Natalia A. , Roellig Daniela , Bronner Marianne , Trainor Paul A. 
Published: April 2019

AbstractNeural crest cells comprise a migratory progenitor cell population that differentiate into cell types such as neurons and glia of the peripheral nervous system, pigment cells, hormone secreting cells in glands, and skeletal and connective tissue in the head, thus making important contributions to most tissues and organs throughout the vertebrate body. The evolutionary appearance of neural crest cells is considered synonymous with the origin of vertebrates and their subsequent diversification and radiation. While the comparative biology of neural crest cells has been studied for a century and a half beginning with their discovery by Wilhelm His in 1868, most of our understanding of their development and function has come from a small number of species. Thus, critical gaps exist in our understanding of how neural crest cells mediate evolution and development. This is particularly true with respect to squamate reptiles (lizards, snakes, amphisbaenians), which account for approximately one‐third of all living tetrapods. Here, we present veiled chameleons (Chamaeleo calyptratus) as a model system for studying neural crest cell development in squamates. Chameleons exhibit various morphological specializations associated with an arboreal lifestyle that may have been facilitated through neural crest cells acting as a conduit for evolutionary change.
Spatiotemporal prediction of wildfire size extremes with Bayesian finite sample maxima
Authors: Joseph Maxwell B. , Rossi Matthew W. , Mietkiewicz Nathan P. , Mahood Adam L. , Cattau Megan E. , St. Denis Lise Ann , Nagy R. Chelsea , Iglesias Virginia , Abatzoglou John T. , Balch Jennifer K. 
Published: April 2019

AbstractWildfires are becoming more frequent in parts of the globe, but predicting where and when wildfires occur remains difficult. To predict wildfire extremes across the contiguous United States, we integrate a 30‐yr wildfire record with meteorological and housing data in spatiotemporal Bayesian statistical models with spatially varying nonlinear effects. We compared different distributions for the number and sizes of large fires to generate a posterior predictive distribution based on finite sample maxima for extreme events (the largest fires over bounded spatiotemporal domains). A zero‐inflated negative binomial model for fire counts and a lognormal model for burned areas provided the best performance. This model attains 99% interval coverage for the number of fires and 93% coverage for fire sizes over a six year withheld data set. Dryness and air temperature strongly predict extreme wildfire probabilities. Housing density has a hump‐shaped relationship with fire occurrence, with more fires occurring at intermediate housing densities. Statistically, these drivers affect the chance of an extreme wildfire in two ways: by altering fire size distributions, and by altering fire frequency, which influences sampling from the tails of fire size distributions. We conclude that recent extremes should not be surprising, and that the contiguous United States may be on the verge of even larger wildfire extremes.
Larval and phenological traits predict insect community response to mowing regime manipulations
Authors: van Klink Roel , Menz Myles H. M. , Baur Hannes , Dosch Oliver , Kühne Isabel , Lischer Lukas , Luka Henryk , Meyer Sandro , Szikora Timea , Unternährer Debora , Arlettaz Raphaël , Humbert Jean‐Yves 
Published: April 2019

AbstractFor the restoration of biodiversity in agricultural grasslands, it is essential to understand how management acts as an ecological filter on the resident species. Mowing constitutes such a filter: only species that possess functional traits enabling them to withstand its consequences can persist in the community. We investigated how the timing of mowing modulates this filtering effect for insects. We predicted that two traits drive species responses. Species with larval development within the meadow vegetation will suffer more from mowing than species whose larvae develop in or on the ground, or outside the meadows, while species with a later phenology should benefit from later mowing. We conducted a five‐year experiment, replicated at 12 sites across the Swiss lowlands, applying three different mowing regimes to low‐intensity hay meadows: (1) first cut of the year not earlier than 15 June (control regime); (2) the first cut delayed until 15 July; and (3) leaving an uncut grass refuge on 10–20% of the meadow area (after earliest first cut on 15 June). Before the first cut in years 4 or 5, we sampled larvae of Lepidoptera and sawflies, and adults of moths, parasitoid wasps, wild bees, hoverflies, ground beetles, and rove beetles. Overall, before the first cut of the year, abundances of species with vegetation‐dwelling larvae were higher in meadows with delayed mowing or an uncut grass refuge, with some taxon‐specific variation. In contrast, species whose larval development is independent of the meadow vegetation showed no differences in abundance between mowing regimes. Species richness did not differ among regimes. For species with vegetation‐dwelling larvae, a fourth‐corner analysis showed an association between early phenology and the control regime. No associations were found for the other functional groups. Our results show that slight modifications of mowing regimes, easily implementable in agri‐environmental policy schemes, can boost invertebrate abundance, potentially benefitting insectivorous vertebrates.
Bio‐energetic modeling of medium‐sized cetaceans shows high sensitivity to disturbance in seasons of low resource supply
Authors: Hin Vincent , Harwood John , de Roos André M. 
Published: April 2019

AbstractUnderstanding the full scope of human impact on wildlife populations requires a framework to assess the population‐level repercussions of nonlethal disturbance. The Population Consequences of Disturbance (PCoD) framework provides such an approach, by linking the effects of disturbance on the behavior and physiology of individuals to their population‐level consequences. Bio‐energetic models have been used as implementations of PCoD, as these integrate the behavioral and physiological state of an individual with the state of the environment, to mediate between disturbance and biological significant changes in vital rates (survival, growth, and reproduction). To assess which levels of disturbance lead to adverse effects on population growth rate requires a bio‐energetic model that covers the complete life cycle of the organism under study. In a density‐independent setting, the expected lifetime reproductive output of a single female can then be used to predict the level of disturbance that leads to population decline. Here, we present such a model for a medium‐sized cetacean, the long‐finned pilot whale (Globicephala melas). Disturbance is modeled as a yearly recurrent period of no resource feeding for the pilot whale female and her calf. Short periods of disturbance lead to the pre‐weaned death of the first one or more calves of the young female. Higher disturbance levels also affect survival of calves produced later in the life of the female, in addition to degrading female survival. The level of disturbance that leads to a negative population growth rate strongly depends on the available resources in the environment. This has important repercussion for the timing of disturbance if resource availability fluctuates seasonally. The model predicts that pilot whales can tolerate on average three times longer periods of disturbance in seasons of high resource availability, compared to disturbance happening when resources are low. Although our model is specifically parameterized for pilot whales, it provides useful insights into the general consequences of nonlethal disturbance. If appropriate data on life history and energetics are available, it can be used to provide management advice for specific species or populations.
Future changes in fire weather, spring droughts, and false springs across U.S. National Forests and Grasslands
Authors: Martinuzzi Sebastián , Allstadt Andrew J. , Pidgeon Anna M. , Flather Curtis H. , Jolly William M. , Radeloff Volker C. 
Published: April 2019

AbstractPublic lands provide many ecosystem services and support diverse plant and animal communities. In order to provide these benefits in the future, land managers and policy makers need information about future climate change and its potential effects. In particular, weather extremes are key drivers of wildfires, droughts, and false springs, which in turn can have large impacts on ecosystems. However, information on future changes in weather extremes on public lands is lacking. Our goal was to compare historical (1950–2005) and projected mid‐century (2041–2070) changes in weather extremes (fire weather, spring droughts, and false springs) on public lands. This case study looked at the lands managed by the U.S. Forest Service across the conterminous United States including 501 ranger district units. We analyzed downscaled projections of daily records from 19 Coupled Model Intercomparison Project 5 General Circulation Models for two climate scenarios, with either medium‐low or high CO2− equivalent concentration (RCPs 4.5 and 8.5). For each ranger district, we estimated: (1) fire potential, using the Keetch‐Byram Drought Index; (2) frequency of spring droughts, using the Standardized Precipitation Index; and (3) frequency of false springs, using the extended Spring Indices. We found that future climates could substantially alter weather conditions across Forest Service lands. Under the two climate scenarios, increases in wildfire potential, spring droughts, and false springs were projected in 32–72%, 28–29%, and 13–16% of all ranger districts, respectively. Moreover, a substantial number of ranger districts (17–30%), especially in the Southwestern, Pacific Southwest, and Rocky Mountain regions, were projected to see increases in more than one type of weather extreme, which may require special management attention. We suggest that future changes in weather extremes could threaten the ability of public lands to provide ecosystem services and ecological benefits to society. Overall, our results highlight the value of spatially‐explicit weather projections to assess future changes in key weather extremes for land managers and policy makers.