bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of cannabinoids from a surrogate hops matrix using multiple reaction monitoring gas chromatography with triple quadrupole mass spectrometry
Authors: Leghissa Allegra , Hildenbrand Zacariah L. , Foss Frank W. , Schug Kevin A. 
Published: November 2017

AbstractCannabinoids are the primary bioactive constituents of Cannabis sativa and Cannabis indica plants. In this work, gas chromatography in conjunction with triple quadrupole mass spectrometry in multiple reaction monitoring mode was explored for determination of cannabinoids from a surrogate hops matrix. Gas chromatography with mass spectrometry is a reasonable choice for the analysis of these compounds; however, such methods are susceptible to false positives for Δ9‐tetrahydrocannabinol, due to decarboxylation of Δ9‐tetrahydrocannabinolic acid, its acid precursor, in the hot injection port. To avoid this transformation, the carboxyl group of Δ9‐tetrahydrocannabinolic acid was protected through a silylation reaction. Multiple reaction monitoring transitions for both unmodified and silylated cannabinoids were developed and the fragmentation pathways for the different species were assigned. Precision and accuracy were evaluated for cannabinoids spiked into hops at different levels. The developed methods provided good linearity (R2 > 0.99) for all the cannabinoids with a linear range from 0.15 to 20 mg/L, and with limits of detection in the orders of low‐ to mid‐picogram on column. The recoveries for the cannabinoids were generally between 75 and 120%. Precisions (<6% coefficient of variation) were within acceptable ranges.
Risk factors of pediatric tinnitus: Systematic review and meta‐analysis
Authors: Lee Doh Young , Kim Young Ho 
Published: November 2017

Objectives/HypothesisMedications for pediatric tinnitus are not widely used due to a lack of evidence‐based information. The modification of risk factors is essential in pediatric tinnitus; however, there is a lack of systematic reviews despite several reports on risk factors. This study performed a systematic review and meta‐analysis of available literature to evaluate risk factors of pediatric tinnitus.MethodsStudies reporting the risk factors of pediatric tinnitus were systematically reviewed by searching the MEDLINE, PubMed, and Embase databases for studies published from database inception to 2016. The selected articles included clinical or epidemiological studies conducted with at least 50 subjects and at least one risk factor, including age, gender, hearing loss, noise exposure, or smoking.ResultsEleven studies involving a total of 28,358 individuals were identified. Increased age was not a significant risk factor with a standardized median difference of 0.16 (95% confidence interval [CI]: −0.01 to 0.33). However, there was a significant correlation between increased age and tinnitus in the adolescent population. The odds ratio (OR) was 1.37 for female gender (95% CI: 1.17 to 1.60), 2.39 for hearing loss (95% CI: 1.48 to 3.87), and 11.35 for noise exposure (95% CI: 1.87 to 68.77). Two studies in adolescents showed statistical significance for smoking as a risk factor in developing tinnitus (OR: 6.05, 95% CI: 1.81 to 20.21).ConclusionsOlder‐aged adolescents, as well as those who are females and those with hearing loss may have a higher risk of tinnitus. Noise exposure in the general pediatric population and smoking in adolescents may represent especially important risk factors in pediatric tinnitus. Laryngoscope, 128:1462–1468, 2018
Transductive Ridge Regression in Structure‐activity Modeling
Authors: Marcou Gilles , Delouis Grace , Mokshyna Olena , Horvath Dragos , Lachiche Nicolas , Varnek Alexandre 
Published: November 2017

AbstractIn this article we consider the application of the Transductive Ridge Regression (TRR) approach to structure‐activity modeling. An original procedure of the TRR parameters optimization is suggested. Calculations performed on 3 different datasets involving two types of descriptors demonstrated that TRR outperforms its non‐transductive analogue (Ridge Regression) in more than 90 % of cases. The most significant transductive effect was observed for small datasets. This suggests that transduction may be particularly useful when the data are expensive or difficult to collect.
Dietary Vitamin K and Association with Hepatic Vitamin K Status in a Yup'ik Study Population from Southwestern Alaska
Authors: Au Nicholas T. , Ryman Tove , Rettie Allan E. , Hopkins Scarlett E. , Boyer Bert B. , Black Jynene , Philip Jacques , Yracheta Joseph , Fohner Alison E. , Reyes Morayma , Thornton Timothy A. , Austin Melissa A. , Thummel Kenneth E. 
Published: November 2017

ScopeThe relationship between dietary vitamin K and plasma PIVKA‐II concentration, a biomarker of hepatic vitamin K status, in a Yup'ik study population in southwestern Alaska is investigated.Methods and resultsA total of 659 male and female, self‐reported Yup'ik people, ≥14 years of age, were enrolled. Blood is collected for genotyping and plasma PIVKA‐II biomarker analysis. A Yup'ik‐specific dietary food frequency questionnaire is used to assess vitamin K intake. Among the participants, 22% report not consuming foods rich in vitamin K during the past year and 36% have a PIVKA‐II concentration ≥ 2 ng mL–1, indicating vitamin K insufficiency. The odds of an elevated PIVKA‐II concentration are 33% lower in individuals reporting any versus no consumption of vitamin‐K‐rich foods. The association is significant after adjusting for CYP4F2*3 genotype. Tundra greens are high in vitamin K1 content, but an exploratory analysis suggests that subsistence meat sources have a greater effect on vitamin K status.ConclusionsA substantial proportion of the Yup'ik population exhibits vitamin K insufficiency, which is associated with low consumption of vitamin K rich foods and which might affect an individual's response to anticoagulant drugs such as warfarin that target the vitamin K cycle.
Cyclometalated Pt complex based random terpolymers as electron acceptors for all polymer solar cells
Authors: Gao Xuyu , Wang Menghan , Cao Xudong , Yang Jie , Zhong Yu , Zhang Zhiguo , Li Cheng , Huettner Sven , Tao Youtian , Li Yongfang , Huang Wei 
Published: November 2017

ABSTRACTVarious molar ratios of platinum complexes were introduced into the conjugated backbone of the well‐studied poly[[N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐bithiophene)](PNDIT2) acceptor polymer through random terpolymer approach. Terpolymers PNDIT2Ptx (x = 1, 2 and 5) exhibited slightly higher melting point (Tm), crystallization temperature, HOMO and LUMO energy levels than the control PNDIT2 copolymer due to the introduction of small amount of weaker electron‐withdrawing bulky rigid Pt complex instead of strong electron‐withdrawing flexible naphthalene diimide. When blended them with poly[[2,6′‐4,8‐di(5‐ethylhexylthienyl)benzo[1,2‐b;3,3‐b] dithiophene] [3‐fluoro‐2[(2‐ethylhexyl)carbonyl]thieno[3,4‐b]thiophenediyl]] (PTB7‐Th) in all polymer solar cells, enhanced power conversion efficiency of 4.51% (3.74%) was obtained in terpolymer PNDIT2Pt1 based device compared to 3.88% (3.24%) of the control PNDIT2 at the same inverted (conventional) device conditions. The enhancement was probably ascribed to higher hole and electron transport ability and more efficient charge separation. To the best of our knowledge, this is the first example of random terpolymer acceptors based on heavy metal complexes. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 105–115
Molecular weight dependence of carrier mobility and recombination rate in neat P3HT films
Authors: Dixon Alex G. , Visvanathan Rayshan , Clark Noel A. , Stingelin Natalie , Kopidakis Nikos , Shaheen Sean E. 
Published: November 2017

ABSTRACTThe microstructure dependence of carrier mobility and recombination rates of neat films of poly 3‐hexylthyophene (P3HT) were determined for a range of materials of weight‐average molecular weights,Mw, ranging from 14 to 331 kDa. This variation has previously been shown to modify the polymer microstructure, with low molecular weights forming a one‐phase, paraffinic‐like structure comprised of chain‐extended crystallites, and higher molecular weights forming a semicrystalline structure with crystalline domains being embedded in an amorphous matrix. Using Charge Extraction by Linearly Increasing Voltage (CELIV), we show here that the carrier mobility in P3HT devices peaks for materials ofMw = 48 kDa, and that the recombination rate decreases monotonically with increasing molecular weight. This trend is likely due to the development of a semicrystalline, two‐phase structure with increasingMw, which allows for the spatial separation of holes and electrons into the amorphous and crystalline regions, respectively. This separation leads to decreased recombination. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.2018,56, 31–35
Liprotides assist in folding of outer membrane proteins
Authors: Nedergaard Pedersen Jannik , Skov Pedersen Jan , Otzen Daniel E. 
Published: November 2017

AbstractProteins and lipids can form complexes called liprotides, in which the partially denatured protein forms a shell encasing a lipid core. This effectively stabilizes a lipid micelle in an aqueous solvent and suggests that liprotides may provide a suitable vessel for membrane proteins. Accordingly we have investigated if liprotides consisting of α‐lactalbumin and oleate could aid folding of four different outer membrane proteins (OMPs) tOmpA, PagP, BamA, and OmpF. tOmpA was able to fold in the presence of the liprotide, and folding did not occur if only oleate or α‐lactalbumin were added. Although the liprotides did not fold the other three OMPs on its own, it was able to assist their folding in the presence of vesicles. Incubation with liprotides before folding into vesicles increased the folding yield of the outer membrane proteins to a level higher than using micelles of the non‐ionic surfactant DDM. Even though the liprotide was stable at both high urea concentrations and high pH, it failed to efficiently fold OmpA at high pH. Instead, optimal folding was seen at pH 8–9, suggesting that important changes in the liprotide occurred when increasing the pH. We conclude that an otherwise folding‐inactive fatty acid can be activated when presented by a liprotide and thereby work as an in vitro chaperone for outer membrane proteins.
Editorial introduction: New European youth mobilities
Authors: King Russell , Williams Allan M. 
Published: November 2017

AbstractThis paper introduces and sets the context for a special issue on “New European Youth Mobilities: Motivations, Experiences and Future Prospects,” which derives from the European Union‐funded H2020 “YMOBILITY” project on current youth migrations and transitions across the European Union. It first introduces the YMOBILITY programme and its multimethod, comparative research effort. This is followed by a brief review of secondary data on the changing profile of youth migration and mobility in Europe. Then, we explore definitions of key terms central to the project, such as “youth,” “youth transition,” “mobility,” “skill,” and the notion of the “learning migrant”. The final part of the paper introduces the 6 articles that make up the special issue, highlighting their most significant findings and outlining their value as an integrated set that offers new insights into the role of mobile young people as students and workers within European societies.
SOFT‐SLAM: Computationally efficient stereo visual simultaneous localization and mapping for autonomous unmanned aerial vehicles
Authors: Cvišić Igor , Ćesić Josip , Marković Ivan , Petrović Ivan 
Published: November 2017

AbstractAutonomous navigation of unmanned aerial vehicles (UAVs) in GPS‐denied environments is a challenging problem, especially for small‐scale UAVs characterized by a small payload and limited battery autonomy. A possible solution to the aforementioned problem is vision‐based simultaneous localization and mapping (SLAM), since cameras, due to their dimensions, low weight, availability, and large information bandwidth, circumvent all the constraints of UAVs. In this paper, we propose a stereo vision SLAM yielding very accurate localization and a dense map of the environment developed with the aim to compete in the European Robotics Challenges (EuRoC) targeting airborne inspection of industrial facilities with small‐scale UAVs. The proposed approach consists of a novel stereo odometry algorithm relying on feature tracking (SOFT), which currently ranks first among all stereo methods on the KITTI dataset. Relying on SOFT for pose estimation, we build a feature‐based pose graph SLAM solution, which we dub SOFT‐SLAM. SOFT‐SLAM has a completely separate odometry and mapping threads supporting large loop‐closing and global consistency. It also achieves a constant‐time execution rate of 20 Hz with deterministic results using only two threads of an onboard computer used in the challenge. The UAV running our SLAM algorithm obtained the highest localization score in the EuRoC Challenge 3, Stage IIa–Benchmarking, Task 2. Furthermore, we also present an exhaustive evaluation of SOFT‐SLAM on two popular public datasets, and we compare it to other state‐of‐the‐art approaches, namely ORB‐SLAM2 and LSD‐SLAM. The results show that SOFT‐SLAM obtains better localization accuracy on the majority of datasets sequences, while also having a lower runtime.
Au Nanoclusters Sensitized Black TiO2−x Nanotubes for Enhanced Photodynamic Therapy Driven by Near‐Infrared Light
Authors: Yang Dan , Gulzar Arif , Yang Guixin , Gai Shili , He Fei , Dai Yunlu , Zhong Chongna , Yang Piaoping 
Published: November 2017

AbstractThe low reactive oxygen species production capability and the shallow tissue penetration of excited light (UV) are still two barriers in photodynamic therapy (PDT). Here, Au cluster anchored black anatase TiO2−x nanotubes (abbreviated as Au25/B‐TiO2−x NTs) are synthesized by gaseous reduction of anatase TiO2 NTs and subsequent deposition of noble metal. The Au25/B‐TiO2−x NTs with thickness of about 2 nm exhibit excellent PDT performance. The reduction process increased the density of Ti3+ on the surface of TiO2, which effectively depresses the recombination of electron and hole. Furthermore, after modification of Au25 nanoclusters, the PDT efficiency is further enhanced owing to the changed electrical distribution in the composite, which forms a shallow potential well on the metal–TiO2 interface to further hamper the recombination of electron and hole. Especially, the reduction of anatase TiO2 can expend the light response range (UV) of TiO2 to the visible and even near infrared (NIR) light region with high tissue penetration depth. When excited by NIR light, the nanoplatform shows markedly improved therapeutic efficacy attributed to the photocatalytic synergistic effect, and promotes separation or restrained recombination of electron and hole, which is verified by experimental results in vitro and in vivo.
Sealed‐Bid Reverse Auction Pricing Mechanisms for Federated Satellite Systems
Authors: Pica Udrivolf , Golkar Alessandro 
Published: November 2017

ABSTRACTThis paper develops a framework to simulate and evaluate pricing policies of spacecraft trading commodities, such as data routing, in a federated satellite network. Federated satellite systems allow the reallocation of underutilized assets, enabling their use as services between owners and third parties. The paper, by means of game theory, focuses on sealed‐bid reverse auction pricing schemes, benchmarks first‐price and second‐price auction strategies, and evaluates the associated trade‐offs in terms of performance and cost, and losses in Pareto efficiency introduced by system‐level operation constraints. The analysis considers an application case study for federated satellite systems operating in Low Earth Orbit for commercial purposes. Satellite federations are a novel paradigm envisioning on‐orbit opportunistic sharing of resources through an ad hoc mobile satellite network. The architecture creates the basis for the realization of a commercial cloud computing environment in orbit, with spacecraft establishing communications links between each other leveraging on system design margins. The results of the case study in space provide new insights on the design of federated satellites and their operations while characterizing emergent behaviors and efficient trade‐offs on the Pareto front of the cost–performance curve.
Combination of mechanical and informational modeling to predict hysteresis behavior of I beam‐to‐CFT column connection
Authors: Abdollahzadeh G.R. , Yapang‐Gharavi S. , Hoseinali‐Beygi M. 
Published: November 2017

SummaryThe behavior of beam‐to‐column connections is significantly complicated because it depends on the material, nonlinear relationship between different members, and contact of connecting elements. Their hysteretic response exhibits highly inelastic characteristics and continuous variation in stiffness, strength, and ductility. Therefore, accurate hysteretic models of bolted connections are essential to accurate seismic assessment and design. Composed (Hybrid) modeling approach is presented to represent the complex hysteretic behavior of I beam‐to‐concrete‐filled‐tube (CFT) column bolted connection. For the purpose in this study, experimental evaluation of I beam‐to‐CFT column connection with bolted end‐plate under cyclic loading is done. It must be mentioned to make the connection easily applicable practically and also prepare the column flanges continuity, a connection with the bolts penetrated into the CFT column are used since using the stiffeners in hollow sections is not easily applicable. In the composed mechanical–informational modeling framework, the conventional mechanical model is complemented by information‐based model components. Finally, moment–rotation curves of composed model have been compared with experimental results. Comparison showed that the composed model has a good agreement with experimental results. A newly designed specimen for validation purpose of the composed modeling was made and experimented. Composed model was well applied to predict the behavior of new connections. The presented results show that the composed model has a good ability to predict of hysteretic behavior.
Brine, englacial structure and basal properties near the terminus of McMurdo Ice Shelf, Antarctica
Authors: Campbell S. , Courville Z. , Sinclair S. , Wilner J. 
Published: November 2017

ABSTRACTWe collected ~1300 km of ground-penetrating radar profiles over McMurdo Ice Shelf, Antarctica, using frequencies between 40 and 400 MHz to determine extent, continuity and depth to the brine. We also used profiles to determine meteoric ice thickness and locate englacial features, which may suggest ice shelf instability. The brine extends 9–13 km inland from the ice shelf terminus and covers the entire region between Ross, White and Black Islands. Jump unconformities and basal fractures exist in the brine and ice shelf, respectively, suggesting prior fracturing and re-suturing. One 100 MHz profile, the most distal from the ice shelf edge while still being situated over the brine, simultaneously imaged the brine and bottom of meteoric ice. This suggests a negative brine salinity gradient moving away from the terminus. The meteoric ice bottom was also imaged in a few select locations through blue ice in the ablation zone near Black Island. We suggest that brine, sediment-rich ice and poor antenna coupling on rough ice attenuates the signal in this area. When combined with other recent mass-balance and structural glaciology studies of MIS, our results could contribute to one of the most high-resolution physical models of an ice shelf in Antarctica.
Threefold increase in marine-terminating outlet glacier retreat rates across the Atlantic Arctic: 1992–2010
Authors: Carr J. Rachel , Stokes Chris. R. , Vieli Andreas 
Published: November 2017

ABSTRACTAccelerated discharge through marine-terminating outlet glaciers has been a key component of the rapid mass loss from Arctic glaciers since the 1990s. However, glacier retreat and its climatic controls have not been assessed at the pan-Arctic scale. Consequently, the spatial and temporal variability in the magnitude of retreat, and the possible drivers are uncertain. Here we use remotely sensed data acquired over 273 outlet glaciers, located across the entire Atlantic Arctic (i.e. areas potentially influenced by North Atlantic climate and/or ocean conditions, specifically: Greenland, Novaya Zemlya, Franz Josef Land and Svalbard), to demonstrate high-magnitude, accelerating and near-ubiquitous retreat between 1992 and 2010. Overall, mean retreat rates increased by a factor of 3.5 between 1992 and 2000 (−30.5 m a−1) and 2000–10 (−105.8 m a−1), with 97% of the study glaciers retreating during the latter period. The Retreat was greatest in northern, western and south-eastern Greenland and also increased substantially on the Barents Sea coast of Novaya Zemlya. Glacier retreat showed no significant or consistent relationship with summer air temperatures at decadal timescales. The rate of frontal position change showed a significant, but weak, correlation with changes in sea-ice concentrations. We highlight large variations in retreat rates within regions and suggest that fjord topography plays an important role. We conclude that marine-terminating Arctic outlet glaciers show a common response of rapid and accelerating retreat at decadal timescales.
Flow-induced vibration of two cylinders in tandem and staggered arrangements
Authors: Griffith Martin D. , Lo Jacono David , Sheridan John , Leontini Justin S. 
Published: November 2017

A numerical study of the flow-induced vibration of two elastically mounted cylinders in tandem and staggered arrangements at Reynolds number $Re=200$ is presented. The cylinder centres are set at a streamwise distance of 1.5 cylinder diameters, placing the rear cylinder in the near-wake region of the front cylinder for the tandem arrangement. The cross-stream or lateral offset is varied between 0 and 5 cylinder diameters. The two cylinders are identical, with the same elastic mounting, and constrained to oscillate only in the cross-flow direction. The variation of flow behaviours is examined for static cylinders and for elastic mountings of a range of spring stiffnesses, or reduced velocity. At least seven major modes of flow response are identified, delineated by whether the oscillation is effectively symmetric, and the strength of the influence of the flow through the gap between the two cylinders. Submodes of these are also identified based on whether or not the flow remains periodic. More subtle temporal behaviours, such as period doubling, quasi-periodicity and chaos, are also identified and mapped. Across all of these regimes, the amplitudes of vibration and the magnitude of the fluid forces are quantified. The modes identified span the parameter space between two important limiting cases: two static bodies at varying lateral offset; and two elastically mounted bodies in a tandem configuration at varying spring stiffnesses. Some similarity in the response of extremely stiff or static bodies and extremely slack bodies is shown. This is explained by the fact that the slack bodies are free to move to an equilibrium position and stop, effectively becoming a static system. However, the most complex behaviour appears between these limits, when the bodies are in reasonably close proximity, and the natural structural frequency is close to the vortex shedding frequency of a single cylinder. This appears to be driven by the interplay between a series of time scales, including the vortex formation time, the advection time across the gap between the cylinders and the oscillation period of both bodies. This points out an important difference between this multi-body system and the classic single-cylinder vortex-induced vibration: two bodies in close proximity will not oscillate in a synchronised, periodic manner when their natural structural frequencies are close to the nominal vortex shedding frequency of a single cylinder.