bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparing Survival and Recurrence in Curative Stage I to III Colorectal Cancer in Transfused and Nontransfused Patients
Authors: Talukder Yumna , Stillwell Andrew P. , Siu Simon K. , Ho Yik-Hong
Published: January 2014

Evidence of the association between blood transfusions and its impact on prognostic outcomes in patients who undergo curative resection of colorectal cancer remains controversial. The aim of this study was to determine whether receiving peri-operative blood transfusions during curative colorectal cancer resection affected overall survival, cancer-related survival, and cancer recurrence. This retrospective study was undertaken at The Royal Brisbane and Women's Hospital, Australia, between 1984 and 2004. The outcomes of 1370 patients undergoing curative colorectal cancer resection for TNM stage I to III were analyzed. Four hundred twenty three patients (30.9%) required transfusion and 947 patients (69.1%) did not. Peri-operative transfusion was associated with higher rates of cancer recurrence on multivariate analysis (P = 0.024, RR, 1.257, 95% CI, 1.03–1.53); however, it was not independently associated with poorer overall or cancer-related survival. Where the aim is curative resection, this study contributes to a body of evidence that blood transfusions may be associated with poorer outcomes.
Retrospective Review of Pilonidal Sinus Patients With Early Discharge After Limberg Flap Procedure
Authors: Altintoprak Fatih , Gundogdu Kemal , Ergonenc Tolga , Dikicier Enis , Cakmak Guner , Celebi Fehmi
Published: January 2014

The aim of this study was to evaluate the results of cases with pilonidal sinus (PS) disease that underwent Limberg flap (LF) transposition and to compare the short and long-term results of early discharge cases with those in the literature. A total of 345 patients who underwent rhomboid excision and LF transposition for PS were evaluated retrospectively. No major anesthetic or surgical complications occurred. Partial wound dehiscence, localized flap necrosis, hematoma, wound infection, and seroma rates were determined as 4.0, 2.1, 1.5, 3.3, and 3.7% respectively. All patients other than those with a hematoma or localized necrosis were discharged with a drain in place 24 hours after the operation. The recurrence rate was 3.9% after a mean 33.1-month follow-up (range, 6–72 months). As a result, we found that short and long-term results of patients who underwent LF and were discharged 24 hours after the operation were similar to those in the literature. We suggest that patients without postoperative complications, such as hematoma or flap necrosis, can be discharged early.
The influence of ambient fault temperature on flash‐heating phenomena
Authors: Passelègue François X. , Goldsby David L. , Fabbri Olivier
Published: January 2014

Recent high‐velocity friction experiments on room temperature rocks reveal a dramatic weakening caused by extreme frictional heating and thermal degradation of the strength of microscopic asperity contacts on a slip surface, i.e., “flash” heating. Here we explore the effects of elevated ambient fault temperature, up to that at the base of the Earth's seismogenic zone, on the flash‐heating behavior of quartzite, Westerly granite, and India gabbro. The experiments demonstrate that elevated ambient fault temperature causes 1) an increase in the characteristic weakening velocity for flash heating, and 2) an increase in the friction coefficient at a given velocity above this characteristic weakening velocity. These unexpected results are reconciled with flash‐heating theory when temperature‐specific values of various material parameters are incorporated in existing constitutive descriptions of flash heating. Our results suggest that constitutive equations for flash heating can be extrapolated with confidence to the elevated ambient temperatures of the seismogenic zone.
A new class of complex ejecta resulting from the interaction of two CMEs and its expected geoeffectiveness
Authors: Lugaz N. , Farrugia C. J.
Published: January 2014

A significant portion of transients measured by spacecraft at 1 AU does not show the well‐defined properties of magnetic clouds (MCs). Here we propose a new class of complex, non‐MC ejecta resulting from the interaction of two coronal mass ejections (CMEs) with different orientations, which differ from previously studied multiple‐MC events. At 1 AU, they are associated with a smooth rotation of the magnetic field vector over an extended duration and do not exhibit clear signs of interaction. We determine the characteristics of such events based on a numerical simulation and identify and analyze a potential case in the long‐duration transient event measured in situ on 19–22 March 2001. Such events may result in intense, long‐duration geomagnetic storms, with a sequence sawtooth events, and may sometimes be misidentified as isolated CMEs.
Effects of Mackenzie River discharge and bathymetry on sea ice in the Beaufort Sea
Authors: Nghiem S. V. , Hall D. K. , Rigor I. G. , Li P. , Neumann G.
Published: January 2014

Mackenzie River discharge and bathymetry effects on sea ice in the Beaufort Sea are examined in 2012 when Arctic sea ice extent hit a record low. Satellite‐derived sea surface temperature revealed warmer waters closer to river mouths. By 5 July 2012, Mackenzie warm waters occupied most of an open water area about 316,000 km2. Surface temperature in a common open water area increased by 6.5°C between 14 June and 5 July 2012, before and after the river waters broke through a recurrent landfast ice barrier formed over the shallow seafloor offshore the Mackenzie Delta. In 2012, melting by warm river waters was especially effective when the strong Beaufort Gyre fragmented sea ice into unconsolidated floes. The Mackenzie and other large rivers can transport an enormous amount of heat across immense continental watersheds into the Arctic Ocean, constituting a stark contrast to the Antarctic that has no such rivers to affect sea ice.
Automated determination of auroral breakup during the substorm expansion phase using all‐sky imager data
Authors: Murphy Kyle R. , Miles David M. , Watt Clare E. J. , Rae I. Jonathan , Mann Ian R. , Frey Harald U.
Published: January 2014

This paper describes a novel method for quantitatively and routinely identifying auroral breakup following substorm onset using the Time History of Events and Macroscale Interactions during Substorms all‐sky imagers. Substorm onset is characterized by a brightening of the aurora that is followed by auroral poleward expansion and auroral breakup. This breakup can be identified by a sharp increase in the auroral intensity i(t) and the time derivative of auroral intensity i(t). Utilizing both i(t) and i'(t), we have developed an algorithm for identifying the time interval and spatial location of auroral breakup during the substorm expansion phase based solely on quantifiable characteristics of the optical auroral emissions. We compare the time interval determined by the algorithm to independently identified auroral onset times from three previously published studies. In each case the time interval determined by the algorithm is within error of the onset independently identified by the prior studies. We further show the utility of the algorithm by comparing the breakup intervals determined using the automated algorithm to an independent list of substorm onset times. We demonstrate that 50% of the breakup intervals characterized by the algorithm are within the uncertainty of the times identified in the list. The quantitative description and routine identification of an interval of auroral brightening during the substorm expansion phase provides a foundation for unbiased statistical analysis of the aurora and to probe the physics of the auroral substorm and identify the processes leading to auroral substorm onset.
Testing linear theory of EMIC waves in the inner magnetosphere: Cluster observations
Authors: Lin R.‐L. , Zhang J.‐C. , Allen R. C. , Kistler L. M. , Mouikis C. G. , Gong J.‐C. , Liu S.‐Q. , Shi L.‐Q. , Klecker B. , Sauvaud J.‐A. , Dunlop M. W.
Published: January 2014

In this paper, we test whether time periods with hot proton temperature anisotropy are associated with electromagnetic ion cyclotron (EMIC) waves and whether the plasma conditions during the observed waves satisfy the linear theory threshold condition. We identify 865 events observed by the Composition Distribution Function instrument onboard Cluster spacecraft 4 during 1 January 2001 to 1 January 2011 that exhibit a positive temperature anisotropy (Ahp = T⊥ h/T∥ h − 1) in the 10–40 keV protons. The events occur over an L range from 4 to 10 in all magnetic local times and at magnetic latitudes (MLATs) within ±50°. Of these hot proton temperature anisotropy (HPTA) events, only 68 events have electromagnetic ion cyclotron (EMIC) waves. In these 68 HPTA events, for those at 3.81.0 nT2/Hz mainly appear in the region with fEMIC/fH,eq < 0.8. Two stop bands are present, one near the region with fEMIC/fH,eq ≈ 0.33, the other in the region with 0.8 < fEMIC/fH,eq < 0.9. Most of the EMIC waves in the He, H, and >H bands satisfy Ahp/(Ahp + 1) > fEMIC/fH,lo, Ahp/(Ahp + 1) > 0.45  × fEMIC/fH,lo, and Ahp/(Ahp + 1) < 0.45  × fEMIC/fH,lo. fEMIC,  fH,eq, and fH,lo are the EMIC wave frequency, the magnetic equatorial, and the local proton gyrofrequencies. We also find that the EMIC waves predominantly occur with Ahp > 0.25. By testing a threshold equation for the EMIC instability based on linear theory, we find that for EMIC waves with |MLAT| ≤ 10° in the He, H, and >H bands, the percentages that satisfy the predicted conditions for wave growth by the threshold equation are 15.2%, 24.6%, and 25.6%. For the EMIC waves with |MLAT| > 10° the percentages that satisfy the wave growth predicted conditions are only 2.8%, 2.6%, and 0.0%. Finally, possible reasons for the low forecast accuracies of EMIC waves are suggested.
Magnetotelluric investigations of the lithosphere beneath the central Rae craton, mainland Nunavut, Canada
Authors: Spratt Jessica E. , Skulski Thomas , Craven James A. , Jones Alan G. , Snyder David B. , Kiyan Duygu
Published: January 2014

New magnetotelluric soundings at 64 locations throughout the central Rae craton on mainland Nunavut constrain 2‐D resistivity models of the crust and lithospheric mantle beneath three regional transects. Responses determined from colocated broadband and long‐period magnetotelluric recording instruments enabled resistivity imaging to depths of > 300 km. Strike analysis and distortion decomposition on all data reveal a regional trend of 45–53°, but locally the geoelectric strike angle varies laterally and with depth. The 2‐D models reveal a resistive upper crust to depths of 15–35 km that is underlain by a conductive layer that appears to be discontinuous at or near major mapped geological boundaries. Surface projections of the conductive layer coincide with areas of high grade, Archean metasedimentary rocks. Tectonic burial of these rocks and thickening of the crust occurred during the Paleoproterozoic Arrowsmith (2.3 Ga) and Trans‐Hudson orogenies (1.85 Ga). Overall, the uppermost mantle of the Rae craton shows resistivity values that range from ~3000 Ω m in the northeast (beneath Baffin Island and the Melville Peninsula) to ~10,000 Ω m beneath the central Rae craton, to >50,000 Ω m in the south near the Hearne Domain. Near‐vertical zones of reduced resistivity are identified within the uppermost mantle lithosphere that may be related to areas affected by mantle melt or metasomatism associated with emplacement of Hudsonian granites. A regional decrease in resistivities to values of ~500 Ω m at depths of 180–220 km, increasing to 300 km near the southern margin of the Rae craton, is interpreted as the lithosphere‐asthenosphere boundary.
Antigorite‐induced seismic anisotropy and implications for deformation in subduction zones and the Tibetan Plateau
Authors: Shao Tongbin , Ji Shaocheng , Kondo Yosuke , Michibayashi Katsuyoshi , Wang Qian , Xu Zhiqin , Sun Shengsi , Marcotte Denis , Salisbury Matthew H.
Published: January 2014

The present study, which is a follow‐up of the Journal of Geophysical Research paper by Ji et al. (2013a), provides a new calibration for both seismic and fabric properties of antigorite serpentinites. Comparisons of the laboratory velocities of antigorite serpentinites measured at high pressures with crystallographic‐preferred orientation data measured using electron backscatter diffraction techniques demonstrate that seismic anisotropy in high T serpentinite, which is essentially controlled by the antigorite c axis fabric, is independent on the operating slip system but strongly dependent on the regime and magnitude of finite strain experienced by the rock. Extrapolation of the experimental data with both pressure and temperature suggests that Vp anisotropy decreases but shear wave splitting (ΔVs) and Vp/Vs increase with increasing pressure in either cold or hot subduction zones. For a cold, steeply subducting slab, antigorite is most likely deformed by nearly coaxial flattening or trench‐parallel movements, forming trench‐parallel seismic anisotropy. For a hot, shallowly subducting slab, however, antigorite is most likely deformed by simple shear or transpression. Trench‐normal seismic anisotropy can be observed when the subducting dip angle is smaller than 30°. The geophysical characteristics of the Tibetan Plateau such as strong heterogeneity in Vp, Vs and attenuation, shear wave splitting and electric conductivity may be explained by the presence of strongly deformed serpentinites in lithospheric shear zones reactivated along former suture zones between amalgamated blocks, hydrated zones of subducting lithospheric mantle, and the crust‐mantle boundary if the temperature is below 700°C in the region of interest.
Diagnosing shortwave cryosphere radiative effect and its 21st century evolution in CESM
Authors: Perket Justin , Flanner Mark G. , Kay Jennifer E.
Published: January 2014

We incorporate a new diagnostic called the cryosphere radiative effect (CrRE), the instantaneous influence of surface snow and sea ice on the top‐of‐model solar energy budget, into two released versions of the Community Earth System Model (CESM1 and CCSM4). CrRE offers a more climatically relevant metric of the cryospheric state than snow and sea ice extent and is influenced by factors such as the seasonal cycle of insolation, cloud masking, and vegetation cover. We evaluate CrRE during the late 20th century and over the 21st century, specifically diagnosing the nature of CrRE contributions from terrestrial and marine sources. The radiative influence of ice sheets and glaciers is not considered, but snow on top of them is accounted for. Present‐day global CrRE in both models is −3.8 W m−2, with a boreal component (−4.2 to −4.6 W m−2) that compares well with observationally derived estimates (−3.9 to −4.6 W m−2). Similar present‐day CrRE in the two model versions results from compensating differences in cloud masking and sea ice extent. Over the 21st century, radiative forcing in the Representative Concentration Pathway (RCP) 8.5 scenario causes reduced boreal sea ice cover, austral sea ice cover, and boreal snow cover, which all contribute roughly equally to enhancing global absorbed shortwave radiation by 1.4–1.8 Wm−2. Twenty‐first century RCP8.5 global cryospheric albedo feedback are +0.41 and +0.45 W/m2/K, indicating that the two models exhibit similar temperature‐normalized CrRE change.
ZnSe‐Based Longitudinal Twinning Nanowires
Authors: Xu Jing , Lu Aijiang , Wang Chunrui , Zou Rujia , Liu Xiaoyun , Wu Xing , Wang Yuxi , Li Sijia , Sun Litao , Chen Xiaoshuang , Oh Hongseok , Baek Hyeonjun , Yi Gyu‐Chul , Chu Junhao
Published: January 2014

Zinc blende ZnSe longitudinal twinning nanowires and a sandwich structure with the wurtzite ZnSe inserting into the zinc blende ZnSe longitudinal twinning nanowires are fabricated via a simple thermal evaporation method. The high‐resolution transmission electron microscope images of the two types of nanowires match well with simulated atomic models of them. The growth of them might be caused by the crystal plane slip during the phase transformation process between the wurtzite and the zinc blende ZnSe nanowire. The vibrating and luminescence properties of the as‐grown longitudinal twinning nanowire are investigated by room‐temperature Raman and low‐temperature (10 K) photoluminescence spectroscopy, respectively. The electrical transport properties of the two types of longitudinal twinning ZnSe nanowires and the monocrystal ZnSe nanowires were compared using in situ measurement in transmission electron microscope.
Fracture Toughness Healing in Epoxy Containing Both Epoxy and Amine Loaded Capsules
Authors: Neuser Sam , Chen Philipp W. , Studart André. R. , Michaud Véronique
Published: January 2014

The feasibility of self‐healing epoxy matrices using the same chemistry as the matrix material, namely a standard epoxy‐amine system, is demonstrated. The two‐component self‐healing system is encapsulated in core‐shell structures using standard in situ curing in a stirred emulsion and a novel microfluidic encapsulation technique for the epoxy monomer and the amine hardener, respectively. The recovery of fracture toughness after room temperature healing is above 50%, and increases to 100% when shape memory alloy wires are combined with a low temperature cure of the matrix to enhance crack closure. This healing ability is also preserved for higher curing temperatures, demonstrating the potential of this novel approach.
Rapid Formation of a Monolayer of Oriented Hard‐Magnetic Strontium Hexaferrite Nanoparticles on a Solid Substrate
Authors: Kushnir Sergey E. , Koshkodaev Dmitry S. , Kazin Pavel E. , Zuev Dmitry M. , Zaytsev Dmitry D. , Jansen Martin
Published: January 2014

Single crystal nanoplatelets of M‐type strontium hexaferrite, which were prepared by oxide glass crystallization, form colloidal solutions after consequent leaching and peptization of the nanocrystalline material. The colloids are stabilized by the particles charging to a zeta‐potential of about 50 mV. Monolayers of oriented platelet strontium hexaferrite nanoparticles form readily on a glass surface while immersing the substrate in the colloidal solution due to Columb attraction of the positively charged nanoparticles to the negatively charged surface. The films show almost rectangular magnetization hysteresis loops typical for strongly textured hard‐magnetic material.
Foldable Textile Electronic Devices Using All‐Organic Conductive Fibers
Authors: Miura Hiroaki , Fukuyama Yasuhiro , Sunda Takashi , Lin Bangjia , Zhou Jian , Takizawa Junko , Ohmori Akio , Kimura Mutsumi
Published: January 2014

Scalable conductive multifilament of poly(3,4‐ethylenedioxythiophene) doped with poly(4‐styrene sulfonate) (PEDOT:PSS) and poly(vinyl alcohol) (PVA) was fabricated by a coagulation of spinning dope solution in cold methanol. The multifilament was composed of uniform circular fibers with an average diameter of 60 ± 5 μm and showed good enough mechanical properties for textile processes while maintaining electronic conductivity. The PEDOT:PSS/PVA blended fibers displayed an actuation response when a voltage was applied in air and the foldable textiles based on the PEDOT:PSS/PVA blended fibers worked as flexible electrodes to detect human heartbeats. The organic conductive fibers can be a platform for lightweight wearable electronics.
Delivering Colloidal Nanoparticles to Mammalian Cells: A Nano–Bio Interface Perspective
Authors: Verderio Paolo , Avvakumova Svetlana , Alessio Giulia , Bellini Michela , Colombo Miriam , Galbiati Elisabetta , Mazzucchelli Serena , Avila Jesus Peñaranda , Santini Benedetta , Prosperi Davide
Published: January 2014

Understanding the behavior of multifunctional colloidal nanoparticles capable of biomolecular targeting remains a fascinating challenge in materials science with dramatic implications in view of a possible clinical translation. In several circumstances, assumptions on structure–activity relationships have failed in determining the expected responses of these complex systems in a biological environment. The present Review depicts the most recent advances about colloidal nanoparticles designed for use as tools for cellular nanobiotechnology, in particular, for the preferential transport through different target compartments, including cell membrane, cytoplasm, mitochondria, and nucleus. Besides the conventional entry mechanisms based on crossing the cellular membrane, an insight into modern physical approaches to quantitatively deliver nanomaterials inside cells, such as microinjection and electro­poration, is provided. Recent hypotheses on how the nanoparticle structure and functionalization may affect the interactions at the nano–bio interface, which in turn mediate the nanoparticle internalization routes, are highlighted. In addition, some hurdles when this small interface faces the physiological environment and how this phenomenon can turn into different unexpected responses, are discussed. Finally, possible future developments oriented to synergistically tailor biological and chemical properties of nanoconjugates to improve the control over nanoparticle transport, which could open new scenarios in the field of nanomedicine, are addressed.
Role of Extracellular Matrix Signaling Cues in Modulating Cell Fate Commitment for Cardiovascular Tissue Engineering
Authors: Nakayama Karina H. , Hou Luqia , Huang Ngan F.
Published: January 2014

It is generally agreed that engineered cardiovascular tissues require cellular interactions with the local milieu. Within the microenvironment, the extracellular matrix (ECM) is an important support structure that provides dynamic signaling cues in part through its chemical, physical, and mechanical properties. In response to ECM factors, cells activate biochemical and mechanotransduction pathways that modulate their survival, growth, migration, differentiation, and function. This Review describes the role of ECM chemical composition, spatial patterning, and mechanical stimulation in the specification of cardiovascular lineages, with a focus on stem cell differentiation, direct transdifferentiation, and endothelial‐to‐mesenchymal transition. The translational application of ECMs is discussed in the context of cardiovascular tissue engineering and regenerative medicine.
Designing Lubricant‐Impregnated Textured Surfaces to Resist Scale Formation
Authors: Subramanyam Srinivas Bengaluru , Azimi Gisele , Varanasi Kripa K.
Published: January 2014

Scale formation is a widespread problem in industries and households—from scaling of cooking pots in ancient times to the plugging of pipelines in the modern age. Developing surfaces that have a low affinity to scale has been an area of great interest in the last decade. In this work, we demonstrate the anti‐scaling properties of textured surfaces impregnated with a lubricant. Since scale deposition can be reduced by lowering the nucleation rate, which depends on the properties of the substrate, we optimize the design of the lubricant‐impregnated surfaces (LIS) based on the surface tension of the lubricant and its spreading coefficient on the solid. Scale deposition experiments show that the nucleation rate on optimized LIS is reduced owing to their low surface energy and low density of nucleation sites. Mass gain measurements indicate that the optimized LIS perform 10 times better than uncoated smooth surfaces. This idea is extended to an engineering material like stainless steel and, along with low scale deposition, low adhesion of scale to LIS is also achieved.
Synthesis of Spiro[chroman/tetrahydrothiophene‐3,3′‐oxindole] ScaffoldsviaHeteroatom‐Michael–Michael Reactions: Easily Controlled EnantioselectivityviaBifunctional Catalysts
Authors: Huang Youming , Zheng Changwu , Chai Zhuo , Zhao Gang
Published: January 2014

An efficient method for the construction of chiral spirooxindole‐chroman and spirooxindole‐tetrahydrothiophene scaffolds with three consecutive chiral centers including an all‐carbon quaternary spirocenter has been developed. This method features an asymmetric thia/oxa‐Michael–Michael cascade sequence in a single operation in the presence of chiral tertiary amine‐thioureas as the catalysts, providing the desired products in good chemical yields and optical purities.

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Copper‐Catalyzed Decarboxylative CN Triple Bond Formation: Direct Synthesis of Benzonitriles from Phenylacetic Acids Under O2 Atmosphere
Authors: Feng Qiang , Song Qiuling
Published: January 2014

A copper‐catalyzed reaction of phenylacetic acids with urea was found to afford benzonitriles under an oxygen atmosphere. This reaction proceeds smoothly by a sequence of decarboxylation, dioxygen activation, CH bond functionalization, and nitrile formation with urea as the nitrogen source. Molecular oxygen was found to play a crucial role in this transformation. This reaction represents a novel protocol for the formation of benzonitriles in an environmental friendly way and with good functional group tolerability.

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Hydrodynamic feedback on bubble breakup at a T‐junction within an asymmetric loop
Authors: Fu Taotao , Ma Youguang , Li Huai Z.
Published: January 2014

Bubble breakup at a microfluidic T‐junction by taking into consideration the hydrodynamic feedback at the downstream channels is presented. Experiments are conducted in square microchannels with 400 μm in width. The splitting ratio of the bubble size in the bifurcations varies nonmonotonically with the flow rate ratio of gas/liquid phases, and it is also affected by the liquid viscosity. A critical size of the mother bubble determines the variation trend of the splitting ratio of bubble size with flow rates of both phases and the liquid viscosity, which is related to the different breakup mechanisms for long and short bubbles at the junction and the different additional resistances induced by long and short bubbles in downstream channels. A theoretical model is proposed to predict the tailoring size of bubbles at the T‐junction by taking into account of the additional resistance in the presence of bubbles in downstream channels. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1920–1929, 2014
Influence of ash agglomerating fluidized bed reactor scale‐up on coal gasification characteristics
Authors: Song Yuncai , Feng Jie , Jia Yalong , Li Wenying , Fang Yitian
Published: January 2014

To study the influence of fluidized‐bed reactor scale‐up on coal gasification characteristics, a model of the ash agglomerating fluidized‐bed reactor has been developed using an equivalent reactor network method. With the reactor network model, the scale‐up effects of a gasifier were studied in terms of the characteristics of the chemical reactions in the jet zone, the annulus dense‐phase zone and the freeboard zone. Results showed that the changes occurred in the inequality proportion of the volume of the jet zone during the reactor scale‐up. Taking into consideration the utilization of a portion of the backflow gas, the expansion of the jet zone volume and the coal particle residence time, the temperature of the jet zone was increased from 1592 to 1662 K. Also, both the annulus dense‐phase zone temperature and the freeboard zone temperature decreased, causing subsequent decrease in the carbon conversion efficiency. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1821–1829, 2014
Oscillatory shear rheology of dilute solutions of flexible polymers interacting with oppositely charged particles
Authors: Radhakrishnan Rangarajan , Underhill Patrick T.
Published: January 2014

Fluids with both attractions and repulsions among its constituents can exist in multiple states depending on nature of the interactions. An external flow can induce such systems to transition between the different states, such as the globule‐stretch transition for polymers in poor solvents. Brownian dynamics simulations of a dilute solution of polymers and colloids interacting via short‐ranged potentials are presented. For some values of the strength and range of interactions, compact structures of polymers and colloids are formed. An external flow is capable of pulling these globules apart, causing the polymers to stretch at a critical shear rate. In oscillatory shear, the shear rate can cycle between being above and below this critical shear rate leading to interesting dynamics. These dynamics are quantified using the rheological response in large amplitude oscillatory shear. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1365–1371, 2014
Sensitive KIT D816V mutation analysis of blood as a diagnostic test in mastocytosis
Authors: Kristensen Thomas , Vestergaard Hanne , Bindslev‐Jensen Carsten , Møller Michael Boe , Broesby‐Olsen Sigurd ,   on Behalf of the Mastocytosis Centre Odense University Hospital (MastOUH)
Published: January 2014

The recent progress in sensitive KIT D816V mutation analysis suggests that mutation analysis of peripheral blood (PB) represents a promising diagnostic test in mastocytosis. However, there is a need for systematic assessment of the analytical sensitivity and specificity of the approach in order to establish its value in clinical use. We therefore evaluated sensitive KIT D816V mutation analysis of PB as a diagnostic test in an entire case‐series of adults with mastocytosis. We demonstrate for the first time that by using a sufficiently sensitive KIT D816V mutation analysis, it is possible to detect the mutation in PB in nearly all adult mastocytosis patients. The mutation was detected in PB in 78 of 83 systemic mastocytosis (94%) and 3 of 4 cutaneous mastocytosis patients (75%). The test was 100% specific as determined by analysis of clinically relevant control patients who all tested negative. Mutation analysis of PB was significantly more sensitive than serum tryptase >20 ng/mL. Of 27 patients with low tryptase, 26 tested mutation positive (96%). The test is furthermore readily available and we consider the results to serve as a foundation of experimental evidence to support the inclusion of the test in diagnostic algorithms and clinical practice in mastocytosis. Am. J. Hematol. 89:493–498, 2014. © 2014 Wiley Periodicals, Inc.
Fluorine in Shark Teeth: Its Direct Atomic‐Resolution Imaging and Strengthening Function
Authors: Chen Chunlin , Wang Zhongchang , Saito Mitsuhiro , Tohei Tetsuya , Takano Yoshiro , Ikuhara Yuichi
Published: January 2014

Atomic‐resolution imaging of beam‐sensitive biominerals is extremely challenging, owing to their fairly complex structures and the damage caused by electron irradiation. Herein, we overcome these difficulties by performing aberration‐corrected electron microscopy with low‐dose imaging techniques, and report the successful direct atomic‐resolution imaging of every individual atomic column in the complex fluorapatite structure of shark tooth enameloid, which can be of paramount importance for teeth in general. We demonstrate that every individual atomic column in shark tooth enameloid can be spatially resolved, and has a complex fluorapatite structure. Furthermore, ab initio calculations show that fluorine atoms can be covalently bound to the surrounding calcium atoms, which improves understanding of their caries‐reducing effects in shark teeth.
Die Existenz von Hexafluorarsen(V)‐säure
Authors: Axhausen Joachim , Lux Karin , Kornath Andreas
Published: January 2014

Die homogene Mischung von wasserfreiem Fluorwasserstoff und Antimonpentafluorid, aHF/AsF5, ist als supersaures System bekannt. Die hohe Säurestärke wird durch die Bildung von [H2F]+ [AsF6]− erklärt. Es gibt keine experimentellen Belege für die Existenz des freien Säuremoleküls HAsF6. Wir haben die Reaktion von Trimethylsilyl‐N,N‐dimethylcarbamat im binären System aHF/AsF5 untersucht und beobachteten die Zersetzung von Trimethylsilyl‐N,N‐dimethylcarbamat bei −50 °C in Dimethylammoniumhexafluoridoarsenat und eine Cokristallisation von HAsF6. Eine Einkristallröntgenstrukturanalyse zeigt ein HAsF6‐Molekül, das eine unsymmetrische Wasserstoffbrücke zu einem Hexafluoridoarsenat‐Anion bildet. Aufgrund der nicht berechenbaren Situation im Kristallgitter wird die Molekülstruktur von HAsF6 durch quantenchemische Strukturoptimierung der beiden Extremfälle [FHF‐AsF5] (starke Wasserstoffbrücke) und HAsF6 (keine Wasserstoffbrücke) auf PBE1PBE/6‐311G(3df,3pd)‐Niveau berechnet.
Rational Perturbation of the Fluorescence Quantum Yield in Emission‐Tunable and Predictable Fluorophores (Seoul‐Fluors) by a Facile Synthetic Method Involving CH Activation
Authors: Choi Eun Joung , Kim Eunha , Lee Youngjun , Jo Ala , Park Seung Bum
Published: January 2014

Fluorescence imaging enables the uniquely sensitive observation of functional‐ and molecular‐recognition events in living cells. However, only a limited range of biological processes have been subjected to imaging because of the lack of a design strategy and difficulties in the synthesis of biosensors. Herein, we report a facile synthesis of emission‐tunable and predictable Seoul‐Fluors, 9‐aryl‐1,2‐dihydrolopyrrolo[3,4‐b]indolizin‐3‐ones, with various R1 and R2 substituents by coinage‐metal‐catalyzed intramolecular 1,3‐dipolar cycloaddition and subsequent palladium‐mediated CH activation. We also showed that the quantum yields of Seoul‐Fluors are controlled by the electronic nature of the substituents, which influences the extent of photoinduced electron transfer. On the basis of this understanding, we demonstrated our design strategy by the development of a Seoul‐Fluor‐based chemosensor 20 for reactive oxygen species that was not accessible by a previous synthetic route.
Xanthomonine I–III: eine neue Klasse von Lassopeptiden mit einem Makrolactamring aus sieben Aminosäureresten
Authors: Hegemann Julian D. , Zimmermann Marcel , Zhu Shaozhou , Steuber Holger , Harms Klaus , Xie Xiulan , Marahiel Mohamed A.
Published: January 2014

Lassopeptide gehören zu den ribosomal synthetisierten und posttranslatorisch modifizierten Peptiden. Ihr gemeinsames Erkennungsmerkmal ist ein N‐terminaler Makrolactamring, der von einem C‐terminalen Schwanz durchfädelt wird. Diese “Lassofaltung” wird durch sterische Wechselwirkungen aufrechterhalten. In dieser Studie werden die Isolierung und Charakterisierung der Xanthomonine I–III, der ersten Lassopeptide mit einem nur aus sieben Aminosäuren bestehenden Makrolactamring, sowie die Kristallstruktur von Xanthomonin I und die NMR‐spektroskopisch ermittelte Struktur von Xanthomonin II beschrieben. Insgesamt wurden 25 Xanthomonin‐II‐Varianten generiert, um Aspekte der Biosynthese, der Stabilisierung und der Aufrechterhaltug der Lassofaltung zu testen. Diese Mutagenesestudie offenbart die Einschränkungen, die ein so kleiner Ring für das Durchfädeln bedeutet, und zeigt, dass jede Stöpselaminosäure größer als Serin eine hitzestabile Lassofaltung in Xanthomonin II aufrechterhalten kann.
Flavoenzym‐katalysierte Bildung von Disulfidbrücken in Naturstoffen
Authors: Scharf Daniel H. , Groll Michael , Habel Andreas , Heinekamp Thorsten , Hertweck Christian , Brakhage Axel A. , Huber Eva M.
Published: January 2014

Die Natur hält Verbindungen verschiedenster chemischer Struktur und biologischer Aktivität bereit, darunter schwefelhaltige Substanzen aus Bakterien und Pilzen. Einige dieser Stoffe enthalten ein Disulfid, das unabdingbar für ihre Bioaktivität ist. Spezielle Oxidoreduktasen wie GliT, HlmI und DepH katalysieren die Bildung dieses Disulfids im Virulenzfaktor Gliotoxin, dem Antibiotikum Holomycin bzw. dem Krebsmedikament Romidepsin. Alle drei Enzyme wurden mithilfe von Röntgenstrukturanalyse und Aktivitätstests untersucht. Trotz ihrer unterschiedlich großen Substrattaschen und ihrer verschiedenen Spezifitäten wird ein gemeinsamer Reaktionsmechanismus postuliert. Dieser basiert auf den erhaltenen Kristallstrukturen und wird durch Mutageneseexperimente gestützt.
Integrated Antimicrobial and Nonfouling Zwitterionic Polymers
Authors: Mi Luo , Jiang Shaoyi
Published: January 2014

Zwitterionic polymers are generally viewed as a new class of nonfouling materials. Unlike their poly(ethylene glycol) (PEG) counterparts, zwitterionic polymers have a broader chemical diversity and greater freedom for molecular design. In this Minireview, we highlight recent microbiological applications of zwitterionic polymers and their derivatives, with an emphasis on several unique molecular strategies to integrate antimicrobial and nonfouling properties. We will also discuss our insights into the bacterial nonfouling performance of zwitterionic polymers and one example of engineering zwitterionic polymer derivatives for antimicrobial wound‐dressing applications.
Quinones as Dienophiles in the Diels–Alder Reaction: History and Applications in Total Synthesis
Authors: Nawrat Christopher C. , Moody Christopher J.
Published: January 2014

In the canon of reactions available to the organic chemist engaged in total synthesis, the Diels–Alder reaction is among the most powerful and well understood. Its ability to rapidly generate molecular complexity through the simultaneous formation of two carboncarbon bonds is almost unrivalled, and this is reflected in the great number of reported applications of this reaction. Historically, the use of quinones as dienophiles is highly significant, being the very first example investigated by Diels and Alder. Herein, we review the application of the Diels–Alder reaction of quinones in the total synthesis of natural products. The highlighted examples span some 60 years from the landmark syntheses of morphine (1952) and reserpine (1956) by Gates and Woodward, respectively, through to the present day examples, such as the tetracyclines.
Xanthomonins I–III: A New Class of Lasso Peptides with a Seven‐Residue Macrolactam Ring
Authors: Hegemann Julian D. , Zimmermann Marcel , Zhu Shaozhou , Steuber Holger , Harms Klaus , Xie Xiulan , Marahiel Mohamed A.
Published: January 2014

Lasso peptides belong to the class of ribosomally synthesized and post‐translationally modified peptides. Their common distinguishing feature is an N‐terminal macrolactam ring that is threaded by the C‐terminal tail. This lasso fold is maintained through steric interactions. The isolation and characterization of xanthomonins I–III, the first lasso peptides featuring macrolactam rings consisting of only seven amino acids, is now presented. The crystal structure of xanthomonin I and the NMR structure of xanthomonin II were also determined. A total of 25 variants of xanthomonin II were generated to probe different aspects of the biosynthesis, stability, and fold maintenance. These mutational studies reveal the limits such a small ring imposes on the threading and show that every plug amino acid larger than serine is able to maintain a heat‐stable lasso fold in the xanthomonin II scaffold.
Rhodium(I)‐Catalyzed Decarbonylative Spirocyclization through CC Bond Cleavage of Benzocyclobutenones: An Efficient Approach to Functionalized Spirocycles
Authors: Xu Tao , Savage Nikolas A. , Dong Guangbin
Published: January 2014

The rhodium‐catalyzed formation of all‐carbon spirocenters involves a decarbonylative coupling of trisubstituted cyclic olefins and benzocyclobutenones through CC activation. The metal–ligand combination [{Rh(CO)2Cl}2]/P(C6F5)3 catalyzed this transformation most efficiently. A range of diverse spirocycles were synthesized in good to excellent yields and many sensitive functional groups were tolerated. A mechanistic study supports a hydrogen‐transfer process that occurs through a β‐H elimination/decarbonylation pathway.
A multiscale correction to the Black–Scholes formula
Authors: Kim Jeong‐Hoon , Lee Jungwoo , Zhu Song‐Ping , Yu Seok‐Hyon
Published: January 2014

Based on a new multiscale hybrid structure of the volatility of the underlying asset price, we study the pricing of a European option in such a way that the resultant option price has a desirable correction to the Black–Scholes formula. The correction effects are obtained by asymptotic analysis based upon the Ornstein–Uhlenbeck diffusion that decorrelates rapidly while fluctuating on a fast time‐scale. The subsequent implied volatilities demonstrate a smile effect (right geometry), which overcomes the major drawback of the Black–Scholes model as well as local volatility models, and move to a right direction as the underlying asset price increases (right dynamics), which fits the observed market behavior and removes the possible instability of hedging that the local volatility models may cope with. Further, we demonstrate that our correction brings significant improvement in terms of fitting to the implied volatility surface through a calibration exercise. Copyright © 2014 John Wiley & Sons, Ltd.
Prevalence of venous thromboembolism at diagnosis of upper gastrointestinal cancer
Authors: Larsen A C , Dabrowski T , Frøkjær J B , Fisker R V , Iyer V V , Møller B K , Kristensen S R , Thorlacius-Ussing O
Published: January 2014

Background

Venous thromboembolism (VTE) in patients with upper gastrointestinal (GI) cancer increases morbidity and mortality. This study aimed to determine the prevalence of VTE at diagnosis of upper GI cancer.

Methods

Patients admitted between February 2008 and February 2011 with upper GI cancer (pancreatic, extrahepatic biliary, lower oesophageal, gastro-oesophageal junction or gastric cancer) were investigated in a cross-sectional cohort study. At cancer diagnosis, all patients were examined for deep vein thrombosis (DVT) by means of bilateral compression ultrasonography. From February 2009 and onwards, computed tomographic pulmonary angiography (CTPA) was also performed for the diagnosis of pulmonary embolism (PE).

Results

Some 250 patients had ultrasonography; CTPA was performed in 143 patients on admission. DVT was detected in 13 (5·2 per cent) of the 250 patients, eight (3·2 per cent) of whom were asymptomatic. DVT was correlated with tumour location in the pancreaticobiliary tract (odds ratio (OR) 6·27, 95 per cent confidence interval 1·18 to 33·38; P = 0·031) and tumour stage IV (OR 19·34, 2·33 to 160·70; P = 0·006). PE was detected in 11 (7·7 per cent) of 143 patients, eight (5·6 per cent) of whom were asymptomatic. PE embolism was also significantly more common in patients with pancreaticobiliary tract cancer (OR 7·81, 1·28 to 47·62; P = 0·026) and in those with stage IV disease (OR 17·19, 1·83 to 161·50; P = 0·013).

Conclusion

The prevalence of VTE at cancer diagnosis was significantly higher in patients with pancreaticobiliary tract cancer than in those with other forms of upper GI cancer, and in patients with advanced cancer stage.
Systematic review of tibial nerve stimulation to treat faecal incontinence
Authors: Horrocks E J , Thin N , Thaha M A , Taylor S J C , Norton C , Knowles C H
Published: January 2014

Background

Two forms of tibial nerve stimulation are used to treat faecal incontinence (FI): percutaneous (PTNS) and transcutaneous (TTNS) tibial nerve stimulation. This article critically appraises the literature on both procedures.

Methods

A systematic review was performed adhering to the PRISMA framework. A comprehensive literature search was conducted, with systematic methodological quality assessment and data extraction. Summary measures for individual outcome variables are reported.

Results

Twelve articles met eligibility criteria; six related to PTNS, five to TTNS, and one to both procedures. These included ten case series and two randomized clinical trials (RCTs). Case series were evaluated using the National Institute for Health and Care Excellence quality assessment for case series, scoring 3–6 of 8. RCTs were evaluated using the Jadad score, scoring 4 of a possible 5 marks, and the Cochrane Collaboration bias assessment tool. From one RCT and case series reports, the success rate of PTNS, based on the proportion of patients who achieved a reduction in weekly FI episodes of at least 50 per cent, was 63–82 per cent, and that of TTNS was 0–45 per cent. In an RCT of TTNSversus sham, no patient had a reduction in weekly FI episodes of 50 per cent or more, whereas in an RCT of PTNSversus TTNSversus sham, 82 per cent of patients undergoing PTNS, 45 per cent of those having TTNS, and 13 per cent of patients in the sham group had treatment success.

Conclusion

PTNS and TTNS result in significant improvements in some outcome measures; however, TTNS was not superior to sham stimulation in a large, adequately powered, RCT. As no adequate RCT of PTNSversus sham has been conducted, conclusions cannot be drawn regarding this treatment.
A Neuregulin‐1 schizophrenia susceptibility variant causes perihippocampal fiber tract anomalies in healthy young subjects
Authors: Nickl‐Jockschat Thomas , Stöcker Tony , Krug Axel , Markov Valentin , Huang Ruiwang , Schneider Frank , Habel Ute , Eickhoff Simon B. , Zerres Klaus , Nöthen Markus M. , Treutlein Jens , Rietschel Marcella , Shah Nadim Jon , Kircher Tilo
Published: January 2014

Background

Changes in fiber tract architecture have gained attention as a potentially important aspect of schizophrenia neuropathology. Although the exact pathogenesis of these abnormalities yet remains to be elucidated, a genetic component is highly likely. Neuregulin‐1 (NRG1) is one of the best‐validated schizophrenia susceptibility genes. We here report the impact of the Neuregulin‐1 rs35753505 variant on white matter structure in healthy young individuals with no family history of psychosis.

Methods

We compared fractional anisotropy in 54 subjects that were either homozygous for the risk C allele carriers (n = 31) for rs35753505 or homozygous for the T allele (n = 23) using diffusion tensor imaging with 3T. Tract‐Based Spatial Statistics (TBSS), a method especially developed for diffusion data analysis, was used to improve white matter registration and to focus the statistical analysis to major fiber tracts.

Results

Statistical analysis showed that homozygous risk C allele carriers featured elevated fractional anisotropy (FA) in the right perihippocampal region and the white matter proximate to the left area 4p as well as the right hemisphere of the cerebellum. We found three clusters of reduced FA values in homozygous C allele carriers: in the left superior parietal region, the right prefrontal white matter and in the deep white matter of the left frontal lobe.

Conclusion

Our results highlight the importance of Neuregulin‐1 for structural connectivity of the right medial temporal lobe. This finding is in line with well known neuropathological findings in this region in patients with schizophrenia.
New Lignans and Their Biological Activities
Authors: Zhang Jia , Chen Jiejun , Liang Zizhen , Zhao Changqi
Published: January 2014

Lignans, which are widely distributed in higher plants, represent a vast and rather diverse group of phenylpropane derivatives. They have attracted considerable attention due to their pharmacological activities. Some of the lignans have been developed approved therapeutics, and others are considered as lead structures for new drugs. This article is based on our previous review of lignans discovered in the period 2000–2004, and it provides a comprehensive compilation of the 354 new naturally occurring lignans obtained from 61 plant families between 2005 and 2011. We classified five main types according to their structural features, and provided the details of their sources, some typical structures, and diverse biological activities. A tabular compilation of the novel lignans by species is presented at the end. A total of 144 references were considered for this review.