bluuebunny/crossref_metadata_2025 huggingface dataset:
Equatorial F region neutral winds and shears near sunset measured with chemical release techniques
Authors: Kiene A. , Larsen M. F. , Kudeki E.
Published: September 2015

The period near sunset is a dynamic and critical time for the daily development of the equatorial nighttime ionosphere and the instabilities that occur there. It is during these hours that the preconditions necessary for the later development of Equatorial Spread F (ESF) plasma instabilities occur. The neutral dynamics of the sunset ionosphere are also of critical importance to the generation of currents and electric fields; however, the behavior of the neutrals is experimentally understood primarily through very limited single‐altitude measurements or measurements that provide weighted altitude means of the winds as a function of time. To date, there have been very few vertically resolved neutral wind measurements in the F region at sunset. We present two sets of sounding rocket chemical release measurements, one from a launch in the Marshall Islands on Kwajalein atoll and one from Alcantara, Brazil. Analysis of the release motions has yielded vertically resolved neutral wind profiles that show both the mean horizontal winds and the vertical shears in the winds. In both experiments, we observe significant vertical gradients in the zonal wind that are unexpected by classical assumptions about the behavior of the neutral wind at these altitudes at sunset near the geomagnetic equator.
Magnetospheric resonances at low and middle latitudes
Authors: Streltsov A. V. , Huba J. D.
Published: September 2015

We present results from a numerical study of structure and dynamics of dispersive Alfvén waves in the near‐Earth magnetosphere containing proton radiation belt (near L = 1.5 dipole magnetic shell). The interest in this problem is motivated by numerous observations of magnetic oscillations with frequencies in the range of 0.1–4.0 Hz detected on the ground at low and middle latitudes. In a number of studies these oscillations interpreted as shear Alfvén waves standing inside the so‐called ionospheric Alfvén resonator. We present results from two‐dimensional, time‐dependent simulations of the reduced two‐fluid MHD model performed in the dipole magnetic field geometry with the realistic parameters of the magnetospheric plasma. These simulations show that these pulsations can be produced by the fundamental mode of the global field line resonator, spanning the entire magnetic field line in the low or middle magnetosphere. Simulations also show that even the waves with the highest considered frequencies (2.44 Hz) are not trapped inside the ionospheric resonator. Therefore, if these waves will be generated by some ionospheric source, then they can reach the equatorial magnetosphere and interact with energetic protons in the proton radiation belt.
Monsoonal loading in Ethiopia and Eritrea from vertical GPS displacement time series
Authors: Birhanu Yelebe , Bendick Rebecca
Published: September 2015

Vertical GPS displacement time series from 16 continuous sites over a period from 2007 to 2014 are compared to time series of monthly averages of liquid water equivalent thickness from the Gravity Recovery and Climate Experiment and precipitation from the Climate Research Unit to investigate hydrologic loading in Ethiopia and Eritrea. The GPS vertical time series record the presence of one or two rainy seasons, the amplitude surface displacements in response to monsoon water load, and phases consistent with a purely elastic response to a water load that accumulates throughout the rainy period. Comparison of observed amplitudes to those calculated for an average Earth model shows no systematic weakness related to the rift.
Borehole strainmeter measurements spanning the 2014 Mw6.0 South Napa Earthquake, California: The effect from instrument calibration
Authors: Langbein John
Published: September 2015

The 24 August 2014 Mw6.0 South Napa, California earthquake produced significant offsets on 12 borehole strainmeters in the San Francisco Bay area. These strainmeters are located between 24 and 80 km from the source, and the observed offsets ranged up to 400 parts per billion (ppb), which exceeds their nominal precision by a factor of 100. However, the observed offsets of tidally calibrated strains differ by up to 130 ppb from predictions based on a moment tensor derived from seismic data. The large misfit can be attributed to a combination of poor instrument calibration and better modeling of the strain field from the earthquake. Borehole strainmeters require in situ calibration, which historically has been accomplished by comparing their measurements of Earth tides with the strain tides predicted by a model. Although the borehole strainmeter accurately measures the deformation within the borehole, the long‐wavelength strain signals from tides or other tectonic processes recorded in the borehole are modified by the presence of the borehole and the elastic properties of the grout and the instrument. Previous analyses of surface‐mounted, strainmeter data and their relationship with the predicted tides suggest that tidal models could be in error by 30%. The poor fit of the borehole strainmeter data from this earthquake can be improved by simultaneously varying the components of the model tides up to 30% and making small adjustments to the point source model of the earthquake, which reduces the RMS misfit from 130 ppb to 18 ppb. This suggests that relying on tidal models to calibrate borehole strainmeters significantly reduces their accuracy.
Generation and propagation of internal tides and solitary waves at the shelf edge of the Bay of Biscay
Authors: Xie X. H. , Cuypers Y. , Bouruet‐Aubertot P. , Pichon A. , Lourenço A. , Ferron B.
Published: September 2015

High‐frequency mooring data were collected near the northern shelf edge of the Bay of Biscay to investigate the generation and propagation of internal tides and internal solitary waves (ISWs). During spring tide, strong nonlinear internal tides and large amplitude ISWs are observed every semidiurnal tidal period. While onshore propagation was expected since the mooring is located shoreward of the maximum internal tidal generation location, both onshore and seaward traveling internal tides are identified. Within a tidal period at spring tide, three ISW packets are observed. Like internal tides, different ISW packets have opposite (seaward and shoreward) propagating direction. Based on realistic hydrostatic HYCOM simulations, it is suggested that advection by the barotropic tide affects wave generation and propagation significantly and is essential for the seaward traveling internal tides to appear shoreward of their generation location. A two‐layer idealized nonhydrostatic model derived by Gerkema (1996) further confirms the effect of advection on the generation and propagation of internal tides. Moreover, the two‐layer model reproduces one seaward propagating ISW packet and one shoreward propagating ISW packet, indicating that the offshore and onshore traveling ISWs are excited by nonlinear steepening of the seaward and shoreward traveling internal tides, respectively.
Identification of new events in Apollo 16 lunar seismic data by Hidden Markov Model‐based event detection and classification
Authors: Knapmeyer‐Endrun Brigitte , Hammer Conny
Published: September 2015

Detection and identification of interesting events in single‐station seismic data with little prior knowledge and under tight time constraints is a typical scenario in planetary seismology. The Apollo lunar seismic data, with the only confirmed events recorded on any extraterrestrial body yet, provide a valuable test case. Here we present the application of a stochastic event detector and classifier to the data of station Apollo 16. Based on a single‐waveform example for each event class and some hours of background noise, the system is trained to recognize deep moonquakes, impacts, and shallow moonquakes and performs reliably over 3 years of data. The algorithm's demonstrated ability to detect rare events and flag previously undefined signal classes as new event types is of particular interest in the analysis of the first seismic recordings from a completely new environment. We are able to classify more than 50% of previously unclassified lunar events, and additionally find over 200 new events not listed in the current lunar event catalog. These events include deep moonquakes as well as impacts and could be used to update studies on temporal variations in event rate or deep moonquakes stacks used in phase picking for localization. No unambiguous new shallow moonquake was detected, but application to data of the other Apollo stations has the potential for additional new discoveries 40 years after the data were recorded. Besides, the classification system could be useful for future seismometer missions to other planets, e.g., the InSight mission to Mars.
A method to estimate trends in distributions of 1 min rain rates from numerical weather prediction data
Authors: Paulson Kevin S. , Ranatunga Channa , Bellerby Timothy
Published: September 2015

It is known that the rain rate exceeded 0.01% of the time in the UK has experienced an increasing trend over the last 20 years. It is very likely that rain fade and outage experience a similar trend. This paper presents a globally applicable method to estimate these trends, based on the widely accepted Salonen‐Poiares Baptista model. The input data are parameters easily extracted from numerical weather prediction reanalysis data. The method is verified using rain gauge data from the UK, and the predicted trend slopes of 0.01% exceeded rain rate are presented on a global grid.
Radar measurement of ionospheric scintillation in the polar region
Authors: Knepp Dennis L.
Published: September 2015

This paper considers several estimators that use radar data to measure the S4 scintillation index that characterizes the severity of amplitude scintillation that may occur during RF propagation through ionospheric irregularities. S4 is defined to be the standard deviation of the fluctuations in received power normalized by division by the mean power. Estimates of S4 are based on radar returns obtained during track of targets which may themselves have intrinsic radar cross‐section fluctuations. Key to this work is the consideration of thresholding, which is used in many radars to remove (from further processing) signals whose SNR is considered too low. We consider several estimators here. The “direct” estimator attempts to estimate S4 through the direct calculation of the mean and standard deviation of the SNR from a number of radar returns. The maximum likelihood (ML) estimator uses multiple hypothesis testing and the assumption of Nakagami‐m statistics to estimate the scintillation index that best fits the radar returns from some number of pulses. The ML estimator has perfect knowledge of the number of radar returns that are below the threshold. The direct estimator is accurate for the case where there is no threshold and there are many returns or samples from which to estimate S4. However, the direct estimator is flawed (especially for strong scintillation) if deep fades that fall below the radar threshold are ignored. The modified ML estimator here is based on the ML technique but is useful if the count of missed returns is unavailable. We apply the modified ML estimator to several years of radar tracks of large calibration satellites to obtain the statistics of UHF scintillation as viewed from the early warning radar at Thule, Greenland. One‐way S4 was measured from 5000 low Earth orbit tracks during the 3 year period after solar maximum in May 2000. The data are analyzed to quantify the exceedance or the level of scintillation experienced at various probabilities. For example, from Thule during the period from December 2001 to February 2002, the probability exceeds 5% that the one‐way scintillation index at UHF is greater than 0.7. On a daily basis this translates into 1.2 h a day of strong scintillation. Unfortunately, there are insufficient data to obtain equivalent information for the winter of solar maximum when the scintillation is likely to be most severe.
Dry‐season length and runoff control annual variability in stream DOC dynamics in a small, shallow groundwater‐dominated agricultural watershed
Authors: Humbert G. , Jaffrezic A. , Fovet O. , Gruau G. , Durand P.
Published: September 2015

As a phenomenon integrating climate conditions and hydrological control of the connection between streams and terrestrial dissolved organic carbon (DOC) sources, groundwater dynamics control patterns of stream DOC characteristics (concentrations and fluxes). Influence of intra‐annual variations in groundwater level, discharge and climatic factors on DOC concentrations and fluxes were assessed over 13 years at the headwater watershed of Kervidy‐Naizin (5 km2) in western France. Four seasonal periods were delineated within each year according to groundwater fluctuations (A: rewetting, B: high flow, C: recession, and D: drought). Annual and seasonal base flow versus stormflow DOC concentrations were defined based on daily hydrograph readings. High interannual variability of annual DOC fluxes (5.4–39.5 kg ha−1 yr−1) indicates that several years of data are required to encompass variations in water flux to evaluate the actual DOC export capacity of a watershed. Interannual variability of mean annual DOC concentrations was much lower (4.9–7.5 mg C L−1), with concentrations decreasing within each year from ca. 9.2 mg C L−1 in A to ca. 3.0 mg C L−1 in C. This indicates an intra‐annual pattern of stream DOC concentrations controlled by DOC source characteristics and groundwater dynamics very similar across years. Partial least squares regressions combined with multiple linear regressions showed that the dry season characteristics (length and drawdown) determine the mean annual DOC concentration while annual runoff determines the annual flux. Antagonistic mechanisms of production‐accumulation and dilution‐depletion combined with an unlimited DOC supply from riparian wetland soils can mitigate the response of stream concentrations to global changes and climatic variations.
Correlation equations for average deposition rate coefficients of nanoparticles in a cylindrical pore
Authors: Seetha N. , Majid Hassanizadeh S. , Mohan Kumar M. S. , Raoof Amir
Published: September 2015

Nanoparticle deposition behavior observed at the Darcy scale represents an average of the processes occurring at the pore scale. Hence, the effect of various pore‐scale parameters on nanoparticle deposition can be understood by studying nanoparticle transport at pore scale and upscaling the results to the Darcy scale. In this work, correlation equations for the deposition rate coefficients of nanoparticles in a cylindrical pore are developed as a function of nine pore‐scale parameters: the pore radius, nanoparticle radius, mean flow velocity, solution ionic strength, viscosity, temperature, solution dielectric constant, and nanoparticle and collector surface potentials. Based on dominant processes, the pore space is divided into three different regions, namely, bulk, diffusion, and potential regions. Advection‐diffusion equations for nanoparticle transport are prescribed for the bulk and diffusion regions, while the interaction between the diffusion and potential regions is included as a boundary condition. This interaction is modeled as a first‐order reversible kinetic adsorption. The expressions for the mass transfer rate coefficients between the diffusion and the potential regions are derived in terms of the interaction energy profile. Among other effects, we account for nanoparticle‐collector interaction forces on nanoparticle deposition. The resulting equations are solved numerically for a range of values of pore‐scale parameters. The nanoparticle concentration profile obtained for the cylindrical pore is averaged over a moving averaging volume within the pore in order to get the 1‐D concentration field. The latter is fitted to the 1‐D advection‐dispersion equation with an equilibrium or kinetic adsorption model to determine the values of the average deposition rate coefficients. In this study, pore‐scale simulations are performed for three values of Péclet number, Pe = 0.05, 5, and 50. We find that under unfavorable conditions, the nanoparticle deposition at pore scale is best described by an equilibrium model at low Péclet numbers (Pe = 0.05) and by a kinetic model at high Péclet numbers (Pe = 50). But, at an intermediate Pe (e.g., near Pe = 5), both equilibrium and kinetic models fit the 1‐D concentration field. Correlation equations for the pore‐averaged nanoparticle deposition rate coefficients under unfavorable conditions are derived by performing a multiple‐linear regression analysis between the estimated deposition rate coefficients for a single pore and various pore‐scale parameters. The correlation equations, which follow a power law relation with nine pore‐scale parameters, are found to be consistent with the column‐scale and pore‐scale experimental results, and qualitatively agree with the colloid filtration theory. These equations can be incorporated into pore network models to study the effect of pore‐scale parameters on nanoparticle deposition at larger length scales such as Darcy scale.
Family Structure
Authors: Pasley Kay , Petren Raymond E.
Published: September 2015

“Family structure” is a term that describes the members of a household who are linked by marriage or bloodline and is typically used in reference to at least one child residing in the home under the age of 18. Today these structures are identified as two‐parent, one‐parent, and “living with neither parent” (e.g., adoptive families, grandparent families or other relatives, foster care families, institutionalized children). However, since the mid‐1940s other changes in family life have resulted in more complicated designations of family structure, including blended families, single‐parent plus partner families (cohabiting couples, both opposite sex and same sex), multigenerational families, and binuclear families). This entry outline the various common definitions of different family structures, identifies changes in family structure over time, and discusses their increasing complexity.
Deformation of Pure Aluminum Along the Groove Path of ECAP‐Conform Process
Authors: Ayati Vahid , Parsa Mohammad Habibi , Mirzadeh Hamed
Published: September 2015

Combining of rotary extrusion and equal channel angular pressing (ECAP) leads to the ECAP‐Conform process, which is one of the few successful continuous severe plastic deformation processes. Sample before reaching the ECAP die is influenced by three main deformations of rolling, bending, and forging, which can affect the microstructure and mechanical properties of the material. The effects of these steps on the microstructure and properties of AA1100 alloy are studied based on the simulation and experimental investigations. It is found that these steps significantly affect the material and they should be considered for evaluation of properties compared with the conventional ECAP.
Nanostructured MWCNT/Polypyrrole Actuators with Anisotropic Strain Response
Authors: Schnoor Thea I. W. , Vainio Ulla , Shao Li‐Hua , Lilleodden Erica T. , Müller Martin , Schreyer Andreas , Schulte Karl , Fiedler Bodo
Published: September 2015

Conducting polymers (CP) as an active material in electrochemical actuators are often likened to “artificial muscles”. To transfer the isotropic change of volume in the CP component into an anisotropic actuation as in a natural muscle, different design approaches, mostly bilayer or triple layer bending devices, have been studied. Herein, we report a novel actuator design with an almost linear strain response, consisting of nanostructured aligned multi‐walled carbon nanotube arrays in which each MWCNT is individually coated with a thin layer of polypyrrole.
Reduced cerebrospinal fluid mitochondrial DNA is a biomarker for early‐stage Parkinson's disease
Authors: Pyle Angela , Brennan Rebecca , Kurzawa‐Akanbi Marzena , Yarnall Alison , Thouin Anais , Mollenhauer Brit , Burn David , Chinnery Patrick F. , Hudson Gavin
Published: September 2015

The identification of cell‐free circulating mitochondrial DNA (ccf‐mtDNA) in early‐stage Alzheimer's disease (AD) raised the possibility that the same neurodegenerative effect could be observed in Parkinson's disease (PD). Here, and for the first time, we investigated the role of ccf‐mtDNA in PD, identifying a significant reduction of ccf‐mtDNA in PD patient cerebrospinal fluid (CSF) when compared to controls. Our data demonstrates that CSF ccf‐mtDNA is not only a powerful biomarker for PD, but, given that the effect is also observed in AD, is likely a biomarker for neurodegeneration. Ann Neurol 2015;78:1000–1004
Validating novel tau positron emission tomography tracer [F‐18]‐AV‐1451 (T807) on postmortem brain tissue
Authors: Marquié Marta , Normandin Marc D. , Vanderburg Charles R. , Costantino Isabel M. , Bien Elizabeth A. , Rycyna Lisa G. , Klunk William E. , Mathis Chester A. , Ikonomovic Milos D. , Debnath Manik L. , Vasdev Neil , Dickerson Bradford C. , Gomperts Stephen N. , Growdon John H. , Johnson Keith A. , Frosch Matthew P. , Hyman Bradley T. , Gómez‐Isla Teresa
Published: September 2015

Objective

To examine region‐ and substrate‐specific autoradiographic and in vitro binding patterns of positron emission tomography tracer [F‐18]‐AV‐1451 (previously known as T807), tailored to allow in vivo detection of paired helical filament‐tau–containing lesions, and to determine whether there is off‐target binding to other amyloid/non‐amyloid proteins.

Methods

We applied [F‐18]‐AV‐1451 phosphor screen autoradiography, [F‐18]‐AV‐1451 nuclear emulsion autoradiography, and [H‐3]‐AV‐1451 in vitro binding assays to the study of postmortem samples from patients with a definite pathological diagnosis of Alzheimer disease, frontotemporal lobar degeneration–tau, frontotemporal lobar degeneration–transactive response DNA binding protein 43 (TDP‐43), progressive supranuclear palsy, corticobasal degeneration, dementia with Lewy bodies, multiple system atrophy, cerebral amyloid angiopathy and elderly controls free of pathology.

Results

Our data suggest that [F‐18]‐AV‐1451 strongly binds to tau lesions primarily made of paired helical filaments in Alzheimer brains (eg, intraneuronal and extraneuronal tangles and dystrophic neurites), but does not seem to bind to a significant extent to neuronal and glial inclusions mainly composed of straight tau filaments in non‐Alzheimer tauopathy brains or to lesions containing β‐amyloid, α‐synuclein, or TDP‐43. [F‐18]‐AV‐1451 off‐target binding to neuromelanin‐ and melanin‐containing cells and, to a lesser extent, to brain hemorrhagic lesions was identified.

Interpretation

Our data suggest that [F‐18]‐AV‐1451 holds promise as a surrogate marker for the detection of brain tau pathology in the form of tangles and paired helical filament‐tau–containing neurites in Alzheimer brains but also point to its relatively lower affinity for lesions primarily made of straight tau filaments in non‐Alzheimer tauopathy cases and to the existence of some [F‐18]‐AV‐1451 off‐target binding. These findings provide important insights for interpreting in vivo patterns of [F‐18]‐AV‐1451 retention. Ann Neurol 2015 Ann Neurol 2015;78:Ann Neurol 2015;78:679–696
Uran aus deutschen Nuklearprojekten der 1940er Jahre – eine nuklearforensische Untersuchung
Authors: Mayer Klaus , Wallenius Maria , Lützenkirchen Klaus , Horta Joan , Nicholl Adrian , Rasmussen Gert , van Belle Pieter , Varga Zsolt , Buda Razvan , Erdmann Nicole , Kratz Jens‐Volker , Trautmann Norbert , Fifield L. Keith , Tims Stephen G. , Fröhlich Michaela B. , Steier Peter
Published: September 2015

Wir berichten hier über eine nuklearforensische Analyse verschiedener Uranmaterialien aus deutschen Nuklearprojekten der 1940er Jahre, bei denen Uranmetall in verschiedenen Geometrien verwendet wurde. Mithilfe des 230Th/234U‐Isotopenverhältnisses konnte für das Metall ein Produktionszeitraum von 1940 bis 1943 bestimmt werden. Die geographische Herkunft des Urans wurde anhand des Spurengehalts an Seltenerdelementen und der Strontium‐Isotopenverhältnisse bestimmt. Die Ergebnisse zeigen, dass das bei den deutschen Nuklearprojekten verwendete Uran aus Minen in der Tschechischen Republik stammt. 236U und 239Pu wurden in Spuren nachgewiesen. Diese entsprechen in etwa der Häufigkeit dieser Isotope in Uranerzen, woraus sich ableiten lässt, dass die untersuchten Uranmetalle keinem signifikanten Neutronenfluss ausgesetzt waren.
Divergent Reactivity of Rhodium(I) Carbenes Derived from Indole Annulations
Authors: Li Xiaoxun , Li Hui , Song Wangze , Tseng Po‐Sen , Liu Lingyan , Guzei Ilia A. , Tang Weiping
Published: September 2015

Rhodium(I) carbenes were generated from propargylic alcohol derivatives as the result of a dehydrative indole annulation. Depending on the choice of the electron‐withdrawing group on the aniline nitrogen nucleophile, either a cyclopropanation product or dimerization product was obtained chemoselectively. Intramolecular hydroamidation occurred for the same type of propargylic alcohol derivatives when other transition‐metal catalysts were employed.
Towards Structural‐Functional Mimics of Acetylene Hydratase: Reversible Activation of Acetylene using a Biomimetic Tungsten Complex
Authors: Peschel Lydia M. , Belaj Ferdinand , Mösch‐Zanetti Nadia C.
Published: September 2015

The synthesis and characterization of a biomimetic system that can reversibly bind acetylene (ethyne) is reported. The system has been designed to mimic catalytic intermediates of the tungstoenzyme acetylene hydratase. The thiophenyloxazoline ligand S‐Phoz (2‐(4′,4′‐dimethyloxazolin‐2′‐yl)thiophenolate) is used to generate a bioinspired donor environment around the W center, facilitating the stabilization of W–acetylene adducts. The featured complexes [W(C2H2)(CO)(S‐Phoz)2] (2) and [WO(C2H2)(S‐Phoz)2] (3) are extremely rare from a synthetic and structural point of view as very little is known about W–C2H2 adducts. Upon exposure to visible light, 3 can release C2H2 from its coordination sphere to yield the 14‐electron species [WO(S‐Phoz)2] (4). Under light‐exclusion 4 re‐activates C2H2 making this the first fully characterized system for the reversible activation of acetylene.
Copper‐Catalyzed Formation of α‐Alkoxycycloalkenones from N‐Tosylhydrazones
Authors: Su Naijing , Theorell Juliana A. , Wink Donald J. , Driver Tom G.
Published: September 2015

The combination of 20 mol % of copper iodide and lithium tert‐butoxide triggers the formation of a broad range of substituted, functionalized α‐alkoxy 2H‐naphthalenones from readily available N‐tosylhydrazones. The data suggests that this transformation occurs through cycloaddition of a copper carbenoid with an ester, followed by a Lewis acid‐catalyzed [1,2] alkyl shift of the in situ generated alkoxyepoxide intermediate.
Metal–Ligand Cooperation
Authors: Khusnutdinova Julia R. , Milstein David
Published: September 2015

Metal–ligand cooperation (MLC) has become an important concept in catalysis by transition metal complexes both in synthetic and biological systems. MLC implies that both the metal and the ligand are directly involved in bond activation processes, by contrast to “classical” transition metal catalysis where the ligand (e.g. phosphine) acts as a spectator, while all key transformations occur at the metal center. In this Review, we will discuss examples of MLC in which 1) both the metal and the ligand are chemically modified during bond activation and 2) bond activation results in immediate changes in the 1st coordination sphere involving the cooperating ligand, even if the reactive center at the ligand is not directly bound to the metal (e.g. via tautomerization). The role of MLC in enabling effective catalysis as well as in catalyst deactivation reactions will be discussed.
Uranium from German Nuclear Power Projects of the 1940s— A Nuclear Forensic Investigation
Authors: Mayer Klaus , Wallenius Maria , Lützenkirchen Klaus , Horta Joan , Nicholl Adrian , Rasmussen Gert , van Belle Pieter , Varga Zsolt , Buda Razvan , Erdmann Nicole , Kratz Jens‐Volker , Trautmann Norbert , Fifield L. Keith , Tims Stephen G. , Fröhlich Michaela B. , Steier Peter
Published: September 2015

Here we present a nuclear forensic study of uranium from German nuclear projects which used different geometries of metallic uranium fuel.3b,d, 4 Through measurement of the 230Th/234U ratio, we could determine that the material had been produced in the period from 1940 to 1943. To determine the geographical origin of the uranium, the rare‐earth‐element content and the 87Sr/86Sr ratio were measured. The results provide evidence that the uranium was mined in the Czech Republic. Trace amounts of 236U and 239Pu were detected at the level of their natural abundance, which indicates that the uranium fuel was not exposed to any major neutron fluence.
Synthesis and Stereochemical Assignment of Crypto‐Optically Active 2H6‐Neopentane
Authors: Masarwa Ahmad , Gerbig Dennis , Oskar Liron , Loewenstein Aharon , Reisenauer Hans Peter , Lesot Philippe , Schreiner Peter R. , Marek Ilan
Published: September 2015

The determination of the absolute configuration of chiral molecules is at the heart of asymmetric synthesis. Here we probe the spectroscopic limits for chiral discrimination with NMR spectroscopy in chiral aligned media and with vibrational circular dichroism spectroscopy of the sixfold‐deuterated chiral neopentane. The study of this compound presents formidable challenges since its stereogenicity is only due to small mass differences. For this purpose, we selectively prepared both enantiomers of 2H6‐1 through a concise synthesis utilizing multifunctional intermediates. While NMR spectroscopy in chiral aligned media could be used to characterize the precursors to 2H6‐1, the final assignment could only be accomplished with VCD spectroscopy, despite the fleetingly small dichroic properties of 1. Both enantiomers were assigned by matching the VCD spectra with those computed with density functional theory.
Targeting Human Poly(ADP‐Ribose) Polymerase‐1 with Natural Medicines and Its Potential Applications in Ovarian Cancer Therapeutics
Authors: Song Min , Li Jun‐Lan , Li Xiao‐Ping , Kan Shi‐Feng
Published: September 2015

Targeting poly(ADP‐ribose) polymerase‐1 (PARP‐1) has been established as an efficient therapeutics for advanced ovarian cancer. In this study, we describe an integrated procedure that combines virtual computer screening and an experimental enzyme assay to discover novel potent PARP‐1 inhibitors from more than 130000 commercially available natural products. The protocol employed a stepwise strategy to fast exclude typical PARP‐1 non‐binders and then performing rigorous prediction to identify promising candidates with high potency against PARP‐1. Consequently, eight natural products were hit and tested to determine their inhibitory activities against the PARP‐1 catalytic domain. From these, four compounds, i.e., puerarin, phloretin, chlorogenic acid, and biochanin A, were found to have high or moderate potencies with inhibitory IC50 values of 6, 470, 25, and 86 nM, respectively. The values are comparable to that (IC50 = 1.94 nM) of the FDA‐approved agent olaparib. Structural and energetic analyses of the modeled structures of the PARP‐1 catalytic domain complexed with the newly identified inhibitors revealed a common binding mode in the complexes: the active site of PARP‐1 is composed of a thin polar helix and a flat non‐polar pocket; the inhibitors can form a number of hydrogen bonds and electrostatic forces with the helix, while tightly packing against the pocket to define chemical interactions.
How Information Availability Interacts with Visual Attention during Judgment and Decision Tasks
Authors: Pärnamets Philip , Johansson Roger , Gidlöf Kerstin , Wallin Annika
Published: September 2015

Decisions in front of a supermarket shelf probably involve a mix of visually available information and associated memories—and interactions between those two. Several cognitive processes, such as decision making, search, and various judgments, are therefore likely to co‐occur, and each process will influence visual attention. We conducted two eye‐tracking experiments capturing parts of these features by having participants make either judgments or decisions concerning products that had been previously encoded. Half the time, participants made their choices with full information about the available products and half the time with crucial task‐relevant information removed. By comparing participants' use of visual attention during decisions and search‐based and memory‐based judgments, we can better understand how visual attention is differently employed between tasks and how it depends on the visual environment. We found that participants' visual attention during decisions is sensitive to evaluations already made during encoding and strongly characterized by preferential looking to the options later to be chosen. When the task environment is rich enough, participants engage in advanced integrative visual behavior and improve their decision quality. In contrast, visual attention during judgments made on the same products reflects a search‐like behavior when all information is available and a more focused type of visual behavior when information is removed. Our findings contribute not only to the literature on how visual attention is used during decision making but also to methodological questions concerning how to measure and identify task‐specific features of visual attention in ecologically valid ways. Copyright © 2015 John Wiley & Sons, Ltd.
Development of easy‐to‐use reverse‐phase liquid chromatographic methods for determining PRE‐084, RC‐33 and RC‐34 in biological matrices. The first step for in vivo analysis of sigma1 receptor agonists
Authors: Marra Annamaria , Rossi Daniela , Maggi Lauretta , Corana Federica , Mannucci Barbara , Peviani Marco , Curti Daniela , Collina Simona
Published: September 2015

Over the years there has been a growing interest in the therapeutic potential for central nervous system pathologies of sigma receptor modulators. The widely studied PRE‐084 and our compounds RC‐33 and RC‐34 are very potent and selective sigma 1 receptor agonists that could represent promising drug candidates for Amyotrophic Lateral Sclerosis (ALS). Herein, we develop and validate robust and easy‐to‐use reverse‐phase chromatographic methods suitable for detecting and quantifying PRE‐084, RC‐33 and RC‐34 in mouse blood, brain and spinal cord. An HPLC/UV/ESI‐MS system was employed for analyzing PRE‐084 and an HPLC/UV‐PDA system for determining RC‐33 and RC‐34. Chromatographic separations were achieved on Waters Symmetry RP18 column (150 × 3.9 mm, 5 µm), eluting with water and acetonitrile (both containing 0.1% formic acid) in gradient conditions. The recovery of PRE‐084, RC‐33 and RC‐34 was >95% in all the considered matrices. Their limits of quantitation and detection were also determined. Validation proved the methods be suitable for separating tested compounds from endogenous interferences, being characterized by good sensitivity, linearity, precision and accuracy. A preliminary central nervous system distribution study showed a high distribution of RC‐33 in brain and spinal cord, with concentration values well above the determined limit of quantitation. The proposed methods will be used in future preclinical investigations. Copyright © 2015 John Wiley & Sons, Ltd.
Identification and quantification of the antipsychotics risperidone, aripiprazole, pipamperone and their major metabolites in plasma using ultra‐high performance liquid chromatography–mass spectrometry
Authors: Wijma Rixt A. , van der Nagel Bart C. H. , Dierckx Bram , Dieleman Gwen C. , Touw Daan J. , van Gelder Teun , Koch Birgit C. P.
Published: September 2015

The antipsychotics risperidone, aripiprazole and pipamperone are frequently prescribed for the treatment in children with autism. The aim of this study was to validate an ultra‐high performance liquid chromatography–mass spectrometry method for the quantification of these antipsychotics in plasma. An ultra‐high performance liquid chromatography–mass spectrometry assay was developed for the determination of the drugs and metabolites. Gradient elution was performed on a reversed‐phase column with a mobile phase consisting of ammonium acetate, formic acid in methanol or in Milli‐Q ultrapure water at a flow rate of 0.5 mL/min. The method was validated according to the US Food and Drug Administration guidelines. The analytes were found to be stable enough after reconstitution and injection of only 5 μL improved the accuracy and precision in combination with the internal standard. Calibration curves of all five analytes were linear. All analytes were stable for at least 72 h in the autosampler and the high quality control of 9‐OH‐risperidone was stable for 48 h. The method allows quantification of all analytes. The advantage of this method is the combination of a minimal injection volume, a short run‐time, an easy sample preparation method and the ability to quantify all analytes in one run. Copyright © 2015 John Wiley & Sons, Ltd.
Primary pleural precursor B‐Cell lymphoblastic lymphoma
Authors: Williams Mark S. , Cheesman Edmund , Kaleem Musa , Wynn Robert
Published: September 2015

Key Clinical Message

Intrathoracic lymphoblastic lymphoma (LBL) is classically of T‐cell lineage, but these cases of pleural B‐cell LBL suggest that this is not always the case. Despite the clinical challenges involved every attempt should be made to secure a biopsy and histological diagnosis, as we move into an era of lineage‐directed therapies.
A different type of dominoes in the stomach
Authors: Kalavakunta Jagadeesh K. , Agrawal Yashwant , Tokala Hemasri
Published: September 2015

Key Clinical Message

Ingestion of foreign bodies is one of the common causes of emergency department visits. History, physical examination, and noninvasive imaging such as plain radiography and computer tomography scan can guide us regarding the type and location of the ingested foreign body. Most of the patients can be managed conservatively but few may need endoscopic evaluation and treatment.
Rosai Dorfman disease diagnosed by fine‐needle aspiration cytology in a young man with HIV infection
Authors: Sall Abibatou , Touré Awa Oumar , Ndiaye Fatou Samba , Sène Abdoulaye , Sall Fatimata Bintou , Faye Blaise Félix , Seck Moussa , Diop Saliou
Published: September 2015

Key Clinical Message

RDD (Rosai Dorfman disease) is a rare and benign histiocytic proliferative disorder of unknown etiology. FNAC (Fine‐needle aspiration cytology) is a useful and reliable tool for the diagnosis of RDD, and as such, biopsy is avoidable.
VOx/SiO2 Catalyst Prepared by Grafting VOCl3 on Silica for Oxidative Dehydrogenation of Propane
Authors: Zhu Haibo , Ould‐Chikh Samy , Dong Hailin , Llorens Isabelle , Saih Youssef , Anjum Dalaver H. , Hazemann Jean‐Louis , Basset Jean‐Marie
Published: September 2015

The VOx/SiO2 catalysts for oxidative dehydrogenation of propane were synthesized by a simple grafting method. The VOCl3 was first grafted at the surface of SiO2, which was dehydrated at different temperature (from 200 to 1000 °C). The formed grafted complexes were then calcined in air, leading to the formation of VOx/SiO2 catalysts. The synthesized catalysts were characterized by nitrogen adsorption, SEM, Raman spectroscopy, temperature‐programmed reduction, and extended X‐ray absorption fine structure analysis. The SiO2 pretreatment temperature has an evident effect on the loading and dispersion of VOx on SiO2, which finally affects their catalytic performance. High SiO2 treatment temperature is beneficial to dispersing the vanadium oxide species at the SiO2 surface. These materials are efficient catalysts for the catalytic oxidative dehydrogenation of propane to propylene. The best selectivity to propylene is achieved on the VOx/SiO2‐(1000) catalyst. The high selectivity and activity are well maintained for three days catalytic reaction.
Systematic Investigation of the Effect of Polymerization Routes on the Gas‐Sorption Properties of Nanoporous Azobenzene Polymers
Authors: Buyukcakir Onur , Je Sang Hyun , Park Joonho , Patel Hasmukh A. , Jung Yousung , Yavuz Cafer T. , Coskun Ali
Published: September 2015

Functional‐group‐oriented polymerization strategies have contributed significantly to the initial development of porous polymers and have led to the utilization of several well‐known organic transformations in the synthesis of these polymers. Because there are multiple polymerization routes that can be used to introduce the same chemical functionality, it is very important to demonstrate the effect of different polymerization routes on the gas‐sorption properties of these chemically similar polymers. Herein, we have studied the rich chemistry of azobenzenes and synthesized four chemically similar nanoporous azobenzene polymers (NABs) with surface areas of up to 1021 m2 g−1. The polymerization routes have a significant impact on the pore‐size distributions of the NABs, which directly affects the temperature dependence of the CO2/N2 selectivity. A pore‐width maximum of 6–8 Å, narrow pore‐size distribution, and small particle size (20–30 nm) were very critical for high CO2/N2 selectivity and N2 phobicity, which is associated with azo linkages and realized at warm temperatures. Our findings collectively suggest that an investigation of different polymerization routes for the same chemical functionalization is critical to understand fully the combined effect of textural properties, local environment, and chemical functionalization on the gas‐sorption properties of nanoporous polymers.
Coordination Complexes of a Neutral 1,2,4‐Benzotriazinyl Radical Ligand: Synthesis, Molecular and Electronic Structures, and Magnetic Properties
Authors: Morgan Ian S. , Mansikkamäki Akseli , Zissimou Georgia A. , Koutentis Panayiotis A. , Rouzières Mathieu , Clérac Rodolphe , Tuononen Heikki M.
Published: September 2015

A series of d‐block metal complexes of the recently reported coordinating neutral radical ligand 1‐phenyl‐3‐(pyrid‐2‐yl)‐1,4‐dihydro‐1,2,4‐benzotriazin‐4‐yl (1) was synthesized. The investigated systems contain the benzotriazinyl radical 1 coordinated to a divalent metal cation, MnII, FeII, CoII, or NiII, with 1,1,1,5,5,5‐hexafluoroacetylacetonato (hfac) as the auxiliary ligand of choice. The synthesized complexes were fully characterized by single‐crystal X‐ray diffraction, magnetic susceptibility measurements, and electronic structure calculations. The complexes [Mn(1)(hfac)2] and [Fe(1)(hfac)2] displayed antiferromagnetic coupling between the unpaired electrons of the ligand and the metal cation, whereas the interaction was found to be ferromagnetic in the analogous NiII complex [Ni(1)(hfac)2]. The magnetic properties of the complex [Co(1)(hfac)2] were difficult to interpret owing to significant spin–orbit coupling inherent to octahedral high‐spin CoII metal ion. As a whole, the reported data clearly demonstrated the favorable coordinating properties of the radical 1, which, together with its stability and structural tunability, make it an excellent new building block for establishing more complex metal–radical architectures with interesting magnetic properties.
Poly(aryl ether) Dendrons with Monopyrrolotetrathiafulvalene Unit‐Based Organogels exhibiting Gel‐Induced Enhanced Emission (GIEE)
Authors: Liu Yucun , Lei Wenwei , Chen Tie , Jin Longyi , Sun Guangyan , Yin Bingzhu
Published: September 2015

A series of poly(aryl ether) dendrons with a monopyrrolo‐tetrathiafulvalene unit linked through an acyl hydrazone linkage were designed and synthesized as low molecular mass organogelators (LMOGs). Two of the dendrons could gelate the aromatic solvents and some solvent mixtures, but the others could not gel all solvents tested except forn‐pentanol. A subtle change on the molecular structure produces a great influence on the gelation behavior. Note that the dendrons could form the stable gel in the DMSO/water mixture without thermal treatment and could also form the binary gel with fullerene (C60) in toluene. The formed gels undergo a reversible gel–sol phase transition upon exposure to external stimuli, such as temperature and chemical oxidation/reduction. A number of experiments (SEM, FTIR spectroscopy,1H NMR spectroscopy, and UV/Vis absorption spectroscopy, and XRD) revealed that these dendritic molecules self‐assembled into elastically interpenetrating one‐dimensional fibrillar aggregates and maintain rectangular molecular‐packing mode in organogels. The hydrogen bonding, π–π, and donor–acceptor interactions were found to be the main driving forces for formation of the gels. Moreover, the gel system exhibited gel‐induced enhanced emission (GIEE) property in the visible region in spite of the absence of a conventional fluorophore unit and the fluorescence was effectively quenched by introduction of C60.
The Influence of the Amide Linkage in the FeIII‐Binding Properties of Catechol‐Modified Rosamine Derivatives
Authors: Queirós Carla , Leite Andreia , G. M. Couto Maria , Cunha‐Silva Luís , Barone Giampaolo , de Castro Baltazar , Rangel Maria , M. N. Silva André , M. G. Silva Ana
Published: September 2015

The two new fluorescent ligands RosCat1 and RosCat2 contain catechol receptors connected to rosamine platforms through an amide linkage and were synthesized by using microwave‐assisted coupling reactions of carboxyl‐ or amine‐substituted rosamines with the corresponding catechol units and subsequent deprotection. RosCat1 possesses a reverse amide, whereas RosCat2 has the usual oriented amide bond (HNCO vs. CONH, respectively). The ligands were characterized by means of NMR spectroscopy, mass‐spectrometry, and DFT calculations and X‐ray crystallography studies for RosCat1. The influence of the amide linkage on the photophysical properties of the fluorescent ligands was assessed in different solvents and showed a higher fluorescence quantum yield for RosCat1. The coordination chemistry of these ligands with a FeIII center has been rationalized by mass‐spectrometric analysis and semiempirical calculations. Octahedral FeIII complexes were obtained by the chelation of three RosCat1 or RosCat2 ligands. Interestingly, the unconventional amide connectivity in RosCat1 imposes the formation of an eight‐membered ring on the chelate complex through a “salicylate‐type” mode of coordination.
Unusual Transformation from a Solvent‐Stabilized 1D Coordination Polymer to a Metal–Organic Framework (MOF)‐Like Cross‐Linked 3D Coordination Polymer
Authors: Lee Seung‐Chul , Choi Eun‐Young , Lee Sang‐Beom , Kim Sang‐Wook , Kwon O‐Pil
Published: September 2015

An unusual 1D‐to‐3D transformation of a coordination polymer based on organic linkers containing highly polar push–pull π‐conjugated side chains is reported. The coordination polymers are synthesized from zinc nitrate and an organic linker, namely, 2,5‐bis{4‐[1‐(4‐nitrophenyl)pyrrolidin‐2‐yl]butoxy}terephthalic acid, which possesses highly polar (4‐nitrophenyl)pyrrolidine groups, with high dipole moments of about 7 D. The coordination polymers exhibit an unusual transformation from a soluble, solvent‐stabilized 1D coordination polymer into an insoluble, metal–organic framework (MOF)‐like 3D coordination polymer. The coordination polymer exhibits good film‐forming ability, and the MOF‐like films are insoluble in conventional organic solvents.