bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantification of Reflux Velocity by Duplex Ultrasound in Superficial and Deep Venous Insufficiency and its Correlation in the Assessment of the Clinical Stage of Chronic Venous Insufficiency
Authors: Ibrahim Aliah , Ganzon Simonette 
Published: July 2024

OBJECTIVE: This study aimed to determine the correlation between ultrasound-derived parameters of chronic venous insufficiency (CVI) and the clinical stage of disease.

METHODS: This was a cross-sectional study conducted in a tertiary hospital and included all adult patients who underwent venous duplex ultrasound of the lower extremities with reflux of the superficial and/or deep venous system. The following parameters were measured: vein diameter, reflux duration, peak systolic velocity (PSV), mean diastolic velocity (MDV) and total reflux volume (TRV). Spearman’s Rank-Order coefficient was used to determine the correlation between ultrasound parameters versus the clinical stage of CVI (C0-C6).

RESULTS: There was a weak but statistically significant correlation between clinical stage and MDV in the right peroneal (r=0.240), left femoral (r=0.175) and left popliteal (r=0.192); between clinical stage and PSV in the right peroneal vein (r=0.194); and between clinical stage and TRV in the right peroneal (r=0.186), left great saphenous (r=0.167), left femoral (r=0.194) and left popliteal veins (r=0.201).

CONCLUSION: There is a statistically significant correlation between the clinical stage of CVI and MDV, PSV and TRV, although the correlations are weak.

KEYWORDS: Duplex-derived parameters, chronic venous insufficiency
A turbulent, high magnetic Reynolds number experimental model of Earth's core
Authors: Zimmerman Daniel S. , Triana Santiago Andrés , Nataf Henri‐Claude , Lathrop Daniel P. 
Published: May 2014

AbstractWe present new experimental results from the University of Maryland Three Meter Geodynamo experiment. We drive a fully turbulent flow in water and also in sodium at magnetic Reynolds number Rm = ΔΩ(ro−ri)2/η, up to 715 (about half design maximum) in a spherical Couette apparatus geometrically similar to Earth's core. We have not yet observed a self‐generating dynamo, but we study MHD effects with an externally applied axisymmetric magnetic field. We survey a broad range of Rossby number −68 < Ro = ΔΩ/Ωo< 65 in both purely hydrodynamic water experiments and sodium experiments with weak, nearly passive applied field. We characterize angular momentum transport and substantial generation of internal toroidal magnetic field (the Ω effect) as a function of Ro and find a rich dependence of both angular momentum transport and Ω effect on Ro. Internal azimuthal field generation peaks at Ro = 6 with a gain as high as 9 with weak applied field. At this Rossby number, we also perform experiments with significant Lorentz forces by increasing the applied magnetic field. We observe a reduction of the Ω effect, a large increase in angular momentum transport, and the onset of new dynamical states. The state we reach at maximum applied field shows substantial magnetic field gain in the axial dipole moment, enhancing the applied dipole moment. This intermittent dipole enhancement must come from nonaxisymmetric flow and seems to be a geodynamo‐style feedback involving differential rotation and large‐scale drifting waves.
Roughness effects on absorption and scattering of left‐handed materials
Authors: Xu Peng , Shi Jian‐Cheng 
Published: May 2014

AbstractBistatic scattering and absorptivities from both Gaussian and exponentially correlated rough surfaces of the left‐handed materials (LHMs) are studied numerically for 2‐D geometries in a numerical Maxwell model. The multilevel UV method is employed to accelerate the matrix equation solver. Accuracy is ensured by energy conservation check. Using a set of physical surface parameters of root‐mean‐square heights and correlation lengths, numerical results are illustrated for absorptivities, bistatic scattering, and bistatic transmission of the LHMs. The numerical results show that the presence of the second opposite transmission, from lower medium to upper one for exponentially correlated LHM surfaces, dramatically reduces the absorptivities and enhances the bistatic scattering remarkably. In particular, the exponentially correlated roughness has negative effect on absorption for transverse electric (TE) case. Then all absorptivities for TE case are below that of the planar interface and decrease continuously with the increasing roughness. Due to both the Brewster angle effect and the opposite transmission across exponentially correlated interface, the absorptivities for the transverse magnetic (TM) case of the LHMs increase at first and decrease subsequently down below that of the planar interface. Both polarimetric absorptive characteristics are in completely contrary to those of the right‐handed materials (RHMs), where the absorptivities for both the TE and TM cases are monotonic increasing with the increase of roughness because of its fine‐scale surface features and the increasing effective surface areas. For Gaussian correlated LHM surfaces, however, the second opposite transmission does not exist, thus does not show any evident differences from RHMs, except for the maximum transmission in different directions and beam broadening. In addition, comparisons are also made with the second‐order small perturbation method and Kirchhoff's approximation. In contrary to RHM, the second‐order small perturbation method is no longer valid for TE case for both absorptivity and scattering from exponentially correlated LHM surfaces even for very small perturbation cases. Similar to RHM surfaces, the Kirchhoff's approximation can be only valid to the LHM surfaces with Gaussian correlation function.
The future of global water stress: An integrated assessment
Authors: Schlosser C. Adam , Strzepek Kenneth , Gao Xiang , Fant Charles , Blanc Élodie , Paltsev Sergey , Jacoby Henry , Reilly John , Gueneau Arthur 
Published: May 2014

AbstractWe assess the ability of global water systems, resolved at 282 assessment subregions (ASRs), to the meet water requirements under integrated projections of socioeconomic growth and climate change. We employ a water resource system (WRS) component embedded within the Massachusetts Institute of Technology Integrated Global System Model (IGSM) framework in a suite of simulations that consider a range of climate policies and regional hydroclimate changes out to 2050. For many developing nations, water demand increases due to population growth and economic activity have a much stronger effect on water stress than climate change. By 2050, economic growth and population change alone can lead to an additional 1.8 billion people living under at least moderate water stress, with 80% of these located in developing countries. Uncertain regional climate change can play a secondary role to either exacerbate or dampen the increase in water stress. The strongest climate impacts on water stress are observed in Africa, but strong impacts also occur over Europe, Southeast Asia, and North America. The combined effects of socioeconomic growth and uncertain climate change lead to a 1.0–1.3 billion increase of the world's 2050 projected population living with overly exploited water conditions—where total potential water requirements will consistently exceed surface water supply. This would imply that adaptive measures would be taken to meet these surface water shortfalls and include: water‐use efficiency, reduced and/or redirected consumption, recurrent periods of water emergencies or curtailments, groundwater depletion, additional interbasin transfers, and overdraw from flow intended to maintain environmental requirements.
Isotope and trace element insights into heterogeneity of subridge mantle
Authors: Mallick Soumen , Dick Henry J. B. , Sachi‐Kocher Afi , Salters Vincent J. M. 
Published: May 2014

AbstractGeochemical data for abyssal peridotites are used to determine the relationship to mid‐ocean ridge basalts from several locations at ridge segments on the SW Indian Ridge (SWIR), the Mid‐Cayman‐Rise (MCR), and the Mid‐Atlantic Ridge (MAR). Based on chemical and petrological criteria peridotites are categorized as being either dominantly impregnated with melt or being residual after recent melting. Those that are considered impregnated with melt also have isotopic compositions similar to the basalts indicating impregnation by an aggregate MORB melt. A SWIR and MCR residual peridotite Nd‐isotopic compositions partly overlap the Nd‐isotopic compositions of the basalts but extend to more radiogenic compositions. The differences between peridotite and basalt Nd‐isotopic compositions can be explained by incorporating a low‐solidus component with enriched isotopic signature in the subridge mantle: a component that is preferentially sampled by the basalts. At the MAR, peridotites and associated basalts have overlapping Nd‐isotopic compositions, suggesting a more homogeneous MORB mantle. The combined chemistry and petrography indicates a complex history with several depletion and enrichment events. The MCR data indicate that a low‐solidus component can be a ubiquitous component of the asthenosphere. Residual abyssal peridotites from limited geographic areas also show significant chemical variations that could be associated with initial mantle heterogeneities related to events predating the ridge‐melting event. Sm‐Nd model ages for possible earlier depletion events suggest these could be as old as 2.4 Ga.
Simulation of operational typhoon rainfall nowcasting using radar reflectivity combined with meteorological data
Authors: Wei Chih‐Chiang 
Published: May 2014

AbstractIn this study, a practical typhoon effective rainfall nowcasting (TERN) model was developed for use in real‐time forecasting. The TERN model was derived from a data‐driven adaptive network‐based fuzzy inference system (ANFIS). The model inputs include meteorological data and radar reflectivity data. The model simulation process begins with an online typhoon warning issued by the Central Weather Bureau (CWB) of Taiwan. It is then determined whether the typhoon approaches the study area according to the typhoon track predicted by the CWB. When a typhoon hits Taiwan, various data are received from sensor instruments, including the ground precipitation data, typhoon climatological data, and radar reflectivity factor by using Weather Surveillance Radar, 1988, Doppler (WSR‐88D) products. The study site was Shihmen Catchment. A maximum of 10 typhoon events from 2000 to 2010 were collected. Regarding the model construction, the input combinations of the ground precipitations and reflectivity factors over the catchment functioned as optimal input variables. To verify the practicability of the ANFIS‐based TERN model, Typhoon Krosa, which hit Taiwan in 2007, was simulated. The results demonstrated that the proposed methodology of real‐time rainfall forecasts during typhoon warning periods yielded favorable performance levels, reliably predicting results regarding 1 h to 6 h forecasting horizons.
A new cloud and aerosol layer detection method based on micropulse lidar measurements
Authors: Zhao Chuanfeng , Wang Yuzhao , Wang Qianqian , Li Zhanqing , Wang Zhien , Liu Dong 
Published: May 2014

AbstractThis paper introduces a new algorithm to detect aerosols and clouds based on micropulse lidar measurements. A semidiscretization processing technique is first used to inhibit the impact of increasing noise with distance. The value distribution equalization method which reduces the magnitude of signal variations with distance is then introduced. Combined with empirical threshold values, we determine if the signal waves indicate clouds or aerosols. This method can separate clouds and aerosols with high accuracy, although differentiation between aerosols and clouds are subject to more uncertainties depending on the thresholds selected. Compared with the existing Atmospheric Radiation Measurement program lidar‐based cloud product, the new method appears more reliable and detects more clouds with high bases. The algorithm is applied to a year of observations at both the U.S. Southern Great Plains (SGP) and China Taihu sites. At the SGP site, the cloud frequency shows a clear seasonal variation with maximum values in winter and spring and shows bimodal vertical distributions with maximum occurrences at around 3–6 km and 8–12 km. The annual averaged cloud frequency is about 50%. The dominant clouds are stratiform in winter and convective in summer. By contrast, the cloud frequency at the Taihu site shows no clear seasonal variation and the maximum occurrence is at around 1 km. The annual averaged cloud frequency is about 15% higher than that at the SGP site. A seasonal analysis of cloud base occurrence frequency suggests that stratiform clouds dominate at the Taihu site.
An Immobilised Grubbs 2nd Generation Catalyst for Application in Flow‐Through Devices
Authors: Gmeiner Julia , Seibicke Max , Lang Carolin , Gärtner Ute , Trapp Oliver 
Published: May 2014

AbstractAn improved immobilised Grubbs 2nd generation catalyst and its application in flow‐through devices, shown for on‐column reaction gas chromatography (ocRGC), has been studied. The coupling of a reaction capillary and a separation column in GC/MS allows direct reaction monitoring and analysis of conversion as well as reaction kinetics. The presented permanently bonded N‐heterocyclic carbene ligand shows a great stability and activity in ring closing metathesis reactions. A salt‐free approach was used to generate the carbene ligand, which can be directly monitored by mass spectrometry. The very flexible design of the immobilised ligand system in reaction channels and capillaries of flow through systems allows the preparation of various catalysts using a broad variety of metal precursors. This strategy of immobilised catalytically active complexes offers a wide range of on‐column reactions combinable with fast reaction screening by high throughput experimentation.magnified image
Visible Light Photoredox Catalysis: Investigation of Distal sp3 CH Functionalization of Tertiary Amines for Alkylation Reaction
Authors: Pandey Ganesh , Jadhav Deepak , Tiwari Sandip Kumar , Singh Bhawana 
Published: May 2014

AbstractVisible light‐mediated photoredox activation of 10‐methyl‐9,10‐dihydroacridine in the presence of electron‐deficient alkenes leads to selective γ‐sp3 CH alkylation whereby 4‐alkyl‐N,N‐dimethylanilines produce substituted tetrahydroquinolines by a subsequent alkylation/cyclization sequence involving interesting mechanistic pathways.magnified image
Site Selective Synthesis of Pentaarylpyridines via Multiple Suzuki–Miyaura Cross‐Coupling Reactions
Authors: Reimann Sebastian , Ehlers Peter , Petrosyan Andranik , Kohse Stefanie , Spannenberg Anke , Surkus Annette E. , Ghochikyan Tariel V. , Saghyan Ashot S. , Lochbrunner Stefan , Kühn Oliver , Ludwig Ralf , Langer Peter 
Published: May 2014

AbstractPentaarylpyridines were conveniently prepared in one step by pentafold Suzuki–Miyaura reactions of pentachloropyridine. Moreover, site selective reactions were performed, leading to various substituted arylpyridines. Pentaarylpyridines were studied in detail by means of DFT calculations and by optical spectroscopy.magnified image
Stable Nickel(0) Phosphites as Catalysts for CN Cross‐Coupling Reactions
Authors: Kampmann Sven S. , Sobolev Alexandre N. , Koutsantonis George A. , Stewart Scott G. 
Published: May 2014

AbstractHerein we describe the design and preparation of inexpensive, air‐stable nickel phosphite‐based catalysts for use in the CN cross‐coupling reaction. The combination of nickel tetrakis(triphenyl phosphite) {Ni[P(OPh)3]4} and 1,1′‐bis(diphenylphosphino)ferrocene (dppf), and in particular a newly developed catalyst (dppf)Ni[P(OPh)3]2, were found to be extremely effective in catalyzing a range of amination reactions of anilines and amines with aryl chlorides. This new catalyst system offers an alternative to the bis(cyclooctadienyl)nickel [Ni(COD)2] and palladium(0) catalysts commonly used for CN bond formation.magnified image
Synthesis and Characterization of New Thiophene‐Derived Polymers
Authors: Ruiz Jesica , Gonzalo Beatriz , Laza José Manuel , León Luis Manuel , Moreno María Isabel , Vilas José Luis , Bilbao Elena 
Published: May 2014

ABSTRACTTwo new intrinsically conducting polythiophenes, poly‐1,4‐bis(3‐hexylthiophene)‐dibutyne (P1) and poly‐2′‐thiophene‐5‐hexyl‐2,3′‐bithiophene (P2), are synthesized to improve the processability of polythiophene. P2 exhibits alternating thiophene and alkylthiophene rings, whereas P1 is characterized by triple bonds between alkylthiophene rings. Both polymers are characterized in terms of chemical, electrical, thermal, and mechanical properties using different techniques. The electrical conductivity of both polymers was determined, their values being significantly lower than that of polythiophene. However, the processability of P1 and P2 was higher in comparison with that of polythiophene because the compression process was possible. The conductivity range makes them suitable for electronic applications.
Synthese von Indolen durch ein modifiziertes Koser‐Reagens
Authors: Fra Laura , Millán Alba , Souto José A. , Muñiz Kilian 
Published: May 2014

AbstractEine neue Methode unter metallfreien Bedingungen zur schnellen und produktiven Synthese von Indolen wurde entwickelt. Dieser Prozess beruht auf einer voluminösen Iodverbindung der Familie der Koser‐Reagentien, wobei die Kombination aus Iodosobenzol und 2,4,5‐Tris(isopropyl)benzolsulfonsäure die höchsten Ausbeuten und kürzesten Reaktionszeiten gewährleistet. Dieses Reagens vermittelt die chemoselektive oxidative Cyclisierung von 2‐Vinylanilinen zu Indolen in hohen Ausbeuten und unter milden Reaktionsbedingungen.
In Situ Observation of Surface Species on Iridium Oxide Nanoparticles during the Oxygen Evolution Reaction
Authors: Sanchez Casalongue Hernan G. , Ng May Ling , Kaya Sarp , Friebel Daniel , Ogasawara Hirohito , Nilsson Anders 
Published: May 2014

AbstractAn iridium oxide nanoparticle electrocatalyst under oxygen evolution reaction conditions was probed in situ by ambient‐pressure X‐ray photoelectron spectroscopy. Under OER conditions, iridium undergoes a change in oxidation state from IrIV to IrV that takes place predominantly at the surface of the catalyst. The chemical change in iridium is coupled to a decrease in surface hydroxide, providing experimental evidence which strongly suggests that the oxygen evolution reaction on iridium oxide occurs through an OOH‐mediated deprotonation mechanism.
Improving Site‐Directed RNA Editing In Vitro and in Cell Culture by Chemical Modification of the GuideRNA
Authors: Vogel Paul , Schneider Marius F. , Wettengel Jacqueline , Stafforst Thorsten 
Published: May 2014

AbstractAdenosine‐to‐inosine deamination can be re‐addressed to user‐defined mRNAs by applying phosphothioate/2′‐methoxy‐modified guideRNAs. Dense chemical modification of the guideRNA clearly improves performance of the covalent conjugates inside the living cell. Furthermore, careful positioning of a few modifications controls editing selectivity in vitro and was exploited for the challenging repair of the Factor 5 Leiden missense mutation.
Concurrent Stabilization of π‐Donor and π‐Acceptor Ligands in Aromatized and Dearomatized Pincer [(PNN)Re(CO)(O)2] Complexes
Authors: Mazzotta Michael G. , Pichaandi Kothanda Rama , Fanwick Phillip E. , Abu‐Omar Mahdi M. 
Published: May 2014

AbstractAromatized cationic [(PNN)Re(π acid)(O)2]+ (1) and dearomatized neutral [(PNN*)Re(π acid)(O)2] (2) complexes (where π acid=CO (a), tBuNC (b), or (2,6‐Me2)PhNC (c)), possessing both π‐donor and π‐acceptor ligands, have been synthesized and fully characterized. Reaction of [(PNN)Re(O)2]+ (4) with lithiumhexamethyldisilazide (LiHMDS) yield the dearomatized [(PNN*)Re(O)2] (3). Complexes 1 and 2 are prepared from the reaction of 4 and 3, respectively, with CO or isocyanides. Single‐crystal X‐ray structures of 1 a and 1 b show the expected trans‐dioxo structure, in which the oxo ligands occupy the axial positions and the π‐acidic ligand occupies the equatorial plane in an overall octahedral geometry about the rhenium(V) center. DFT studies revealed the stability of complexes 1 and 2 arises from a π‐backbonding interaction between the dxy orbital of rhenium, the π orbital of the oxo ligands, and the π* orbital of CO/isocyanide.
Preparation of polysiloxane oligomers bearing benzoxazine side groups and tunable properties of their thermosets
Authors: Zhu Chunli , Wei Yanze , Zhang Jing , Geng Pengfei , Lu Zaijun 
Published: May 2014

ABSTRACTA new pathway for the preparation of polysiloxane oligomers bearing benzoxazine side groups were reported via the hydrolysis and co‐polycondensation of benzoxazinyl siloxane (SBZ) with dimethyldiethoxysilane (DEDMS). The structures of SBZ and oligomers were characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. The average molecular weights of the obtained oligomers were estimated from size exclusion chromatography and 1H‐NMR to be in the range of 2000–4000. The oligomers gave transparent films by casting in THF solution. The films were further thermally treated to produce crosslinked films via the ring opening polymerization of benzoxazine side group. The effects of siloxane content on polymerization behavior, glass transition temperature, and mechanical properties of the polybenzoxazine thermosets were investigated. Tensile test of the films revealed that the elongation at break increased with increasing siloxane content. The elongation at break of poly(I‐50) was up to 12.1%. Dynamic mechanical analysis of the thermosets showed that the Tgs were in the range of 119–165°C. Thermogravimetic analysis also revealed a better thermal stability as evidenced by the 5% weight loss temperatures in the range of 363–390°C. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40960.
Effect of carbon nanotube dispersion on the complex permittivity and absorption of nanocomposites in 2–18 GHz ranges
Authors: Yang Ruey‐Bin , Kuo Wen‐Shyong , Lai Heng‐Chih 
Published: May 2014

ABSTRACTThe effect of dispersion processes on complex permittivity
and microwave absorption in 2−18 GHz ranges is presented for nanocomposites loaded with different amounts of carbon nanotubes (CNTs) ranging from 1 to 5 wt %. The ultrasonic sonication (US) method and the three‐roll mill (TRM) method were performed for the manufacturing of the CNT/epoxy absorbers with different dispersing levels. Microscopic observations revealed that the CNT agglomerates were reduced after the TRM process, and individual CNTs were uniformly dispersed in the epoxy resin. For the same weight content of CNT fillers, the percentage increase of
between US and TRM samples varies from 35.5% to 101.7% while the corresponding increment of
(dielectric loss) varies from 79.6% to 248.8%. A minimum reflection loss for the US sample with 2 wt % CNTs is only −7.8 dB at 11.3 GHz while the corresponding TRM sample is greatly improved to reach −37.4 dB at 7.76 GHz for the same matching thickness of 3 mm. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40963.