bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vivo measurement of gas flow in human airways with hyperpolarized gas MRI and compressed sensing
Authors: Collier Guilhem J. , Wild Jim M. 
Published: July 2014

PurposeHyperpolarized (HP) 3He and 129Xe are two gases with different fluid dynamic properties, which can be used as tracers for airflow measurement in the lungs with phase contrast velocimetry MRI sequences. In this work, in vivo measurements of velocity maps of airflow in the upper airways and first bronchi of healthy volunteers were obtained with both gases and compared.Theory and MethodsTo reduce the acquisition time, a Compressed Sensing (CS) based acquisition and reconstruction algorithm was developed and optimized for flow measurement in three directions by including the sparsity of the complex difference images as prior knowledge.ResultsCS simulations on retrospectively under‐sampled images demonstrated a better reconstruction with the inclusion of the complex difference terms in the cost function. The technique was then validated with a prospective acquisition study providing artifact free maps with acceleration factors up to 3.ConclusionThe presented technique opens up the possibility to map velocity inside human lungs. The results are of interest for the validation of computational fluid dynamics flow simulations and for understanding the spatio‐temporal evolution of airflow patterns in the airways in vivo with different gas mixtures. Magn Reson Med 73:2255–2261, 2015. © 2014 Wiley Periodicals, Inc.
Cortical depth dependence of the BOLD initial dip and poststimulus undershoot in human visual cortex at 7 Tesla
Authors: Siero Jeroen C.W. , Hendrikse Jeroen , Hoogduin Hans , Petridou Natalia , Luijten Peter , Donahue Manus J. 
Published: July 2014

PurposeOwing to variability in vascular dynamics across cerebral cortex, blood‐oxygenation‐level‐dependent (BOLD) spatial and temporal characteristics should vary as a function of cortical‐depth. Here, the positive response, initial dip (ID), and post‐stimulus undershoot (PSU) of the BOLD response in human visual cortex are investigated as a function of cortical depth and stimulus duration at 7 Tesla (T).MethodsGradient‐echo echo‐planar‐imaging BOLD fMRI with high spatial and temporal resolution was performed in 7 healthy volunteers and measurements of the ID, PSU, and positive BOLD response were made as a function of cortical depth and stimulus duration (0.5–8 s). Exploratory analyses were applied to understand whether functional mapping could be achieved using the ID, rather than positive, BOLD signal characteristicsResultsThe ID was largest in outer cortical layers, consistent with previously reported upstream propagation of vasodilation along the diving arterioles in animals. The positive BOLD signal and PSU showed different relationships across the cortical depth with respect to stimulus duration.ConclusionThe ID and PSU were measured in humans at 7T and exhibited similar trends to those recently reported in animals. Furthermore, while evidence is provided for the ID being a potentially useful feature for better understanding BOLD signal dynamics, such as laminar neurovascular coupling, functional mapping based on the ID is extremely difficult. Magn Reson Med 73:2283–2295, 2015. © 2014 Wiley Periodicals, Inc.
Mit Tetraedern zum Ziel
Authors: Heine Johanna , Weinert Bastian , Dehnen Stefanie 
Published: July 2014

AbstractMultinäre Metallate und intermetalloide Cluster zeigen eine große Vielfalt bei Strukturen und Reaktivitätsmustern. Binäre, tetraedrische Hauptgruppenelement‐Anionen bieten einen effizienten Zugang zu solchen aus drei und mehr Elementen aufgebauten anorganischen Materialien.
Dreidimensionales wächst
Authors: Gottwald Eric , Haug Peter , Truckenmüller Roman 
Published: July 2014

AbstractDreidimensionale Zellmodelle bilden die Situation im lebenden Organismus besser ab als zweidimensionale; sie eignen sich aber häufig nicht für Hochdurchsatzverfahren. Neue 3‐D‐Systeme mit fixierter Position der Zellen könnten dies ändern.
Elektrochemischer Nitratsensor
Authors: Plumeré Nicolas 
Published: July 2014

AbstractDer Stickstoffbedarf von Nutzpflanzen ist bekannt und der Nitratgehalt im Boden analytisch quantifizierbar, sodass Landwirte die Menge an Düngemittel dem Bedarf anpassen könnten. Sie schrecken jedoch vor den für sie aufwendigen Bodenanalysen zurück und setzen Düngemittel im Überschuss ein. Abhilfe schaffen auf dem Feld einsetzbare Testsysteme mit elektrochemischen Sensoren.
Hilft Uniluft‐Schnuppern gegen Studienabbruch?
Authors: Engel Thomas 
Published: July 2014

AbstractSeit dem Jahr 2006 wählt die Ludwig‐Maximilians‐Universität München Bewerber für den Bachelorstudiengang “Chemie und Biochemie” anhand gewichteter Schulnoten. Seit 2008 überprüfen Studieninteressierte zudem in einem Praktikum vor der Immatrikulation theoretische Kenntnisse sowie praktische Fertigkeiten. Sind durch die beiden Maßnahmen die Studienabbrüche zurückgegangen?
Inventory control and replenishment with flexible delivery‐time upgrade
Authors: Liang Xiaoying , Yan Houmin 
Published: July 2014

AbstractWe consider a capacitated inventory model with flexible delivery upgrades, in which the seller allocates its on‐hand inventory to price‐ and delivery‐time‐sensitive customers. The seller has two decisions: inventory commitment and replenishment. The former addresses how the on‐hand inventories are allocated between the two classes of customers within an inventory cycle. The latter addresses how the inventory is replenished between inventory cycles. We develop optimal inventory allocation, upgrade, and replenishment policies and demonstrate that the optimal policy can be characterized by a set of switching curves. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 418–426, 2014
Oxygen‐enhanced 3D radial ultrashort echo time magnetic resonance imaging in the healthy human lung
Authors: Kruger Stanley J. , Fain Sean B. , Johnson Kevin M. , Cadman Robert V. , Nagle Scott K. 
Published: July 2014

The purpose of this work was to use 3D radial ultrashort echo time (UTE) MRI to perform whole‐lung oxygen‐enhanced (OE) imaging in humans.Eight healthy human subjects underwent two 3D radial UTE MRI acquisitions (TE = 0.08 ms): one while breathing 21% O2 and the other while breathing 100% O2. Scans were each performed over 5 min of free breathing, using prospective respiratory gating. For comparison purposes, conventional echo time (TE = 2.1 ms) images were acquired simultaneously during each acquisition using a radial " outward‐inward" k‐space trajectory. 3D percent OE maps were generated from these images.3D OE maps showing lung signal enhancement were generated successfully in seven subjects (technical failure in one subject). Mean percent signal enhancement was 6.6% ± 1.8%, near the value predicted by theory of 6.3%. No significant enhancement was seen using the conventional echo time data, confirming the importance of UTE for this acquisition strategy.3D radial UTE MRI shows promise as a method for OE MRI that enables whole‐lung coverage and isotropic spatial resolution, in comparison to existing 2D OE methods, which rely on a less time‐efficient inversion recovery pulse sequence. These qualities may help OE MRI become a viable low‐cost method for 3D imaging of lung function in human subjects. Copyright © 2014 John Wiley & Sons, Ltd.
Multigrid‐in‐time for sensitivity analysis of chaotic dynamical systems
Authors: Blonigan Patrick , Wang Qiqi 
Published: July 2014

SummaryThe following paper discusses the application of a multigrid‐in‐time scheme to Least Squares Shadowing (LSS), a novel sensitivity analysis method for chaotic dynamical systems. While traditional sensitivity analysis methods break down for chaotic dynamical systems, LSS is able to compute accurate gradients. Multigrid is used because LSS requires solving a very large Karush–Kuhn–Tucker system constructed from the solution of the dynamical system over the entire time interval of interest. Several different multigrid‐in‐time schemes are examined, and a number of factors were found to heavily influence the convergence rate of multigrid‐in‐time for LSS. These include the iterative method used for the smoother, how the coarse grid system is formed and how the least squares objective function at the center of LSS is weighted.
Thermodynamically consistent algorithms for a finite‐deformation phase‐field approach to fracture
Authors: Hesch C. , Weinberg K. 
Published: July 2014

SUMMARYPhase‐field approaches to fracture offer new perspectives toward the numerical solution of crack propagation. In this paper, a phase‐field method for finite deformations and general nonlinear material models is introduced using a novel multiplicative split of the principal stretches to account for the different behavior of fracture in tension and compression. An energy‐momentum consistent integrator is developed and applied to the arising nonlinear coupled phase‐field model. This approach is thermodynamically consistent in the sense that the first law of thermodynamics if fulfilled with respect to the dissipation function. The capabilities and the performance of the proposed approach is demonstrated in several representative examples. Copyright © 2014 John Wiley & Sons, Ltd.
A massively parallel implementation of the Optimal Transportation Meshfree method for explicit solid dynamics
Authors: Li B. , Stalzer M. , Ortiz M. 
Published: July 2014

SUMMARYPresented is a massively parallel implementation of the Optimal Transportation Meshfree (pOTM) method Li et al., 2010 for explicit solid dynamics. Its implementation is based on a two‐level scheme using Message Passing Interface between compute servers and threaded parallelism on the multi‐core processors within each server. Both layers dynamically subdivide the problem to provide excellent parallel scalability. pOTM is used on three problems and compared to experiments to demonstrate accuracy and performance. For both a Taylor‐anvil and a hypervelocity impact problem, the pOTM implementation scales nearly perfectly to about 8000 cores. Copyright © 2014 John Wiley & Sons, Ltd.
Comparison of the Effects of Combination Diuretic Therapy with Oral Hydrochlorothiazide or Intravenous Chlorothiazide in Patients Receiving Intravenous Furosemide Therapy for the Treatment of Heart Failure
Authors: Kissling Kevin T. , Pickworth Kerry K. 
Published: July 2014

Study ObjectiveTo compare the effects of combination diuretic therapy with oral hydrochlorothiazide or intravenous chlorothiazide added to background intravenous loop diuretic therapy among patients hospitalized with heart failure.DesignSingle‐center, retrospective review.SettingCardiovascular hospital within a university‐affiliated teaching institution.PatientsEighty‐two patients hospitalized for heart failure between September 1, 2009, and August 31, 2011, who were receiving background intravenous furosemide therapy (total daily dose ≥ 160 mg); of those patients, 28 patients also received oral hydrochlorothiazide (median dose 25 mg [interquartile range 25–50 mg]), and 54 patients also received intravenous chlorothiazide (median dose 500 mg [interquartile range 250–750 mg]).Measurements and Main ResultsThe primary outcome was change in 24‐hour urine output. Urine output was recorded from the 24 hours before and after the first administration of either oral hydrochlorothiazide or intravenous chlorothiazide. Baseline characteristics, with the exception of female sex (p=0.01) and home loop diuretic dose (p=0.03), were similar between groups. Twenty‐four–hour urine output before administration of the thiazide diuretic was not significantly different between groups. After treatment, 24‐hour urine output increased in both groups; however, urine output increased to a lesser extent with oral hydrochlorothiazide (from mean ± SD 2104 ± 830 ml to 3038 ± 917 ml) than with intravenous chlorothiazide (from 2342 ± 978 ml to 4128 ± 1755 ml) (p=0.005). Hypokalemia occurred frequently in both groups: 71.4% and 83.3% in the oral hydrochlorothiazide and intravenous chlorothiazide groups, respectively (p=0.21).ConclusionAmong hospitalized patients with heart failure receiving intravenous loop diuretics, the addition of either oral hydrochlorothiazide or intravenous chlorothiazide augmented diuresis. Urine output increased to a greater extent with intravenous chlorothiazide compared with oral hydrochlorothiazide. However, given the positive response observed, ease of administration, and lower drug cost, oral hydrochlorothiazide should still be considered as an option for combination diuretic therapy in this patient population.
Teilchendynamik fern vom Gleichgewicht
Authors: Liebchen Benno , Schmelcher Peter 
Published: July 2014

AbstractFern des thermodynamischen Gleichgewichts kann ungerichtete Bewegung sogar auf atomaren Skalen in gerichtete Bewegung umgewandelt werden. Dieses Phänomen nutzen biologische Organismen seit Urzeiten. Angesichts der beachtlichen Fortschritte der Nanotechnologie und der Miniaturisierung elektronischer Bauteile rücken gerichtete Teilchenströme aber auch zunehmend in den Fokus von Wissenschaft und Technik. Neue Wege zur Kontrolle von Teilchen und gerichteten Teilchenströmen bieten raumzeitlich getriebene Gitter. Insbesondere ermöglichen sie das Sortieren von Teilchen in Mustern und den Transport ganzer Dichtewellen. Teilchen, die untereinander wechselwirken, wie etwa Ionen, zeigen eine nahezu kollektive Konversion von Chaos zu Ordnung. Diese äußert sich in einer überraschenden, selbstständigen Umkehr der Richtung von Teilchenströmen.
Revisiting the structure of the Vps10 domain of human sortilin and its interaction with neurotensin
Authors: Quistgaard Esben M. , Grøftehauge Morten K. , Madsen Peder , Pallesen Lone T. , Christensen Brian , Sørensen Esben S. , Nissen Poul , Petersen Claus M. , Thirup Søren S. 
Published: July 2014

AbstractSortilin is a multifunctional receptor involved in sorting and apoptosis. We have previously reported a 2.0‐Å structure of the Vps10 ectodomain in complex with one of its ligands, the tridecapeptide neurotensin. Here we set out to further characterize the structural properties of sortilin and its interaction with neurotensin. To this end, we have determined a new 2.7 Å structure using a crystal grown with a 10‐fold increased concentration of neurotensin. Here a second peptide fragment was observed within the Vps10 β‐propeller, which may in principle either represent a second molecule of neurotensin or the N‐terminal part of the molecule bound at the previously identified binding site. However, in vitro binding experiments strongly favor the latter hypothesis. Neurotensin thus appears to bind with a 1:1 stoichiometry, and whereas the N‐terminus does not bind on its own, it enhances the affinity in context of full‐length neurotensin. We conclude that the N‐terminus of neurotensin probably functions as an affinity enhancer for binding to sortilin by engaging the second binding site. Crystal packing differs partly from the previous structure, which may be due to variations in the degree and pattern of glycosylations. Consequently, a notable hydrophobic loop, not modeled previously, could now be traced. A computational analysis suggests that this and a neighboring loop may insert into the membrane and thus restrain movement of the Vps10 domain. We have, furthermore, mapped all N‐linked glycosylations of CHO‐expressed human sortilin by mass spectrometry and find that their locations are compatible with membrane insertion of the hydrophobic loops.
Introducing touchstroke: keystroke‐based authentication system for smartphones
Authors: Kambourakis Georgios , Damopoulos Dimitrios , Papamartzivanos Dimitrios , Pavlidakis Emmanouil 
Published: July 2014

AbstractKeystroke dynamics is a well‐investigated behavioural biometric based on the way and rhythm in which someone interacts with a keyboard or keypad when typing characters. This paper explores the potential of this modality but for touchscreen‐equipped smartphones. The main research question posed is whether ‘touchstroking’ can be effective in building the biometric profile of a user, in terms of typing pattern, for future authentication. To reach this goal, we implemented a touchstroke system in the Android platform and executed different scenarios under disparate methodologies to estimate its effectiveness in authenticating the end‐user. Apart from typical classification features used in legacy keystroke systems, we introduce two novel ones, namely, speed and distance. From the experiments, it can be argued that touchstroke dynamics can be quite competitive, at least when compared to similar results obtained from keystroke evaluation studies. As far as we are aware of, this is the first time this newly arisen behavioural trait is put into focus. Copyright © 2014 John Wiley & Sons, Ltd.
A modeling methodology to facilitate safety‐oriented architecture design of industrial avionics software
Authors: Wu Ji , Yue Tao , Ali Shaukat , Zhang Huihui 
Published: July 2014

SummaryEnsuring that avionics software meets safety requirements at each development stage is very important to warrant the safe operation of an avionics system. Many safety requirements are imposed by various standards and industrial regulations that must be met by avionics software. One of such standards is DO‐178B/C, which provides guidelines (e.g., development process and objectives to satisfy in development activities) for meeting safety requirements. This paper presents a modeling methodology including a UML profile for specifying safety requirements on a component‐based architecture model and a set of design guidelines on avionics software. These safety requirements were identified from both standards (mainly DO‐178B/C) and current engineering practices in the domain of avionics systems. The methodology automatically enforces these safety requirements. We have applied the methodology on an industrial autopilot system, and several previously uncaught faults were revealed. Copyright © 2014 John Wiley & Sons, Ltd.
Effects of secondary electron emission coefficients on Townsend's second ionization coefficient in argon dielectric barrier discharges
Authors: Yoshinaga Tomokazu , Akashi Haruaki 
Published: July 2014

AbstractOne‐dimensional fluid model simulations are performed to investigate how the secondary electron emission arising from ions (γi), metastable atoms (γm), and photons (γp) affect Townsend's second ionization coefficient (γ′) in argon dielectric barrier discharges. Since Townsend's breakdown criterion determines the value of γ′, it is naturally affected by the discharge condition such as the reduced electric field (E/p) as well as the combination of γi, γm, and γp. It also depends on the other contributions from the indirect ionization processes such as cumulative ionizations or metastable–metastable collision ionizations. When the nonionic electron‐yielding processes such as the effects of γm, γp, and the indirect ionizations are considered, the calculated γ′ increases largely under the higher pd (pressure times distance) branch of the Paschen curve. Since the experimental characteristics of γ′, which decreases with E/p, can hardly be explained without such nonionic processes, the contributions of those processes can be quite important in Townsend discharges especially under high pd conditions. These processes tend not to appear and γ′ tends to converge to γi under the lower pd branch of the Paschen curve. The value of γi can possibly be estimated by using γ′ under the lower pd condition. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Unitary coherent strategy for spatial sparsity‐based DOA estimation of wideband signals
Authors: Kahaei Mohammad Hossein , Atashbar Mahmoud 
Published: July 2014

AbstractThe coherent l1‐singular value decomposition (l1‐SVD) uses a non‐unitary coherent strategy for transferring different frequency bin data to a reference bin, which decreases the signal‐to‐error ratio (SER) in transferring, thereby leading to a decrease in accuracy in the direction of arrival (DOA) estimation. To cope with this problem, in this paper we propose a unitary coherent strategy that uses unitary focusing matrices for transferring data. Simulation results show that the proposed method outperforms the coherent l1‐SVD method in accurate DOA estimation. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Environmental safety level of lead (Pb) pertaining to toxic effects on grey mullet (Mugil cephalus) and Tiger perch (Terapon jarbua)
Authors: Hariharan G. , Purvaja R. , Ramesh R. 
Published: July 2014

ABSTRACTAcute and chronic bioassay toxicity test of Lead (Pb) in Grey Mullet (Mugil cephalus), and Tiger perch (Terapon jarbua) was conducted. LC50 values (Lethal Concentration) from acute tests and chronic values were calculated by the geometric mean of the No‐Observed‐Effect Concentration (NOEC) and the Lowest‐Observed‐Effect Concentration (LOEC) in a study period of 30 days. This research was conducted to evaluate the quantitative relationship between toxicity test statistics and correlation between toxicant and the organisms exposed. Three test average LC50 was analyzed for 24, 48, 72, and 96 h and the 96 h average LC50 of M. cephalus and T. jarbua is 2.57 ± 0.47 and 2.99 ± 0.23 mg/L of Pb, respectively. Significant correlation is observed with the increased time duration and exposure concentration. The NOEC and LOEC values were calculated based on survival of test organisms for M. cephalus and T. jarbua and the values are 0.014 and 0.029 and 0.011 and 0.022 mg/L, respectively. The chronic value is found to be 0.011 mg/L for M. cephalus and 0.021 mg/L for T. jarbua. The intensity of biochemical and histological alterations increased gradually with increased Pb concentration and the exposure time. Toxicity testing is the primary step to determine the water quality safe limit on marine organisms. The outcome of the study indicates that the sensitivity of juvenile organisms to Pb, persistence of toxic effects and biomarkers as a tool capable of revealing the toxic effects of heavy metals on the environment and aquatic biota. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 24–43, 2016.
The regulatory potential of upstream open reading frames in eukaryotic gene expression
Authors: Wethmar Klaus 
Published: July 2014

Upstream open reading frames (uORFs) are prevalent cis‐regulatory sequence elements in the transcript leader sequences (TLSs) of eukaryotic mRNAs. The majority of uORFs is considered to repress downstream translation by the consumption of functional pre‐initiation complexes or by inhibiting unrestrained progression of the ribosome. Under distinct conditions, specific uORF properties or sequential arrangements of uORFs can oppositely confer enhanced translation of the main coding sequence, designating uORFs as versatile modifiers of gene expression. Ribosome profiling and proteomic studies demonstrated widespread translational activity at AUG‐ and non‐AUG‐initiated uORFs in eukaryotic transcriptomes from yeast to human and several reports linked defective uORF‐mediated translational control to the development of human diseases. This review summarizes the structural features affecting uORF‐mediated translational control in eukaryotes and describes the highly divergent mechanisms of uORF regulation that result in repression or induction of downstream protein translation. WIREs RNA 2014, 5:765–768. doi: 10.1002/wrna.1245This article is categorized under:

RNA Interactions with Proteins and Other Molecules > Small Molecule–RNA Interactions
Translation > Translation Regulation