bluuebunny/crossref_metadata_2025 huggingface dataset:
Charcoal dispersion and deposition in boreal lakes from 3 years of monitoring: Differences between local and regional fires
Authors: Oris France , Ali Adam A. , Asselin Hugo , Paradis Laure , Bergeron Yves , Finsinger Walter
Published: August 2014

To evaluate the influence of long‐distance transport of charcoal particles on the detection of local wildfires from lake sediment sequences, we tracked three consecutive years of charcoal deposition into traps set within seven boreal lakes in northeastern Canada. Peaks in macroscopic charcoal accumulation (>150 µm) were linked to both local (inside the watershed) and regional wildfires. However, regional fires were characterized by higher proportions of small particles (<0.1 mm2) in charcoal assemblages. We conclude that the analysis of particle size distribution is useful to discriminate “true” local fires from regional wildfires.
The preparatory phase of the 2009 Mw 6.3 L'Aquila earthquake by improving the detection capability of low‐magnitude foreshocks
Authors: Sugan Monica , Kato Aitaro , Miyake Hiroe , Nakagawa Shigeki , Vuan Alessandro
Published: August 2014

We explored the detection capability of low‐magnitude earthquakes before the 6 April 2009 Mw 6.3 L'Aquila event by using a matched filter technique and 512 foreshocks as templates. We analyzed continuous waveforms from 10 broadband seismic stations in a 60 km radius from the epicenter and for ~3 months before the main shock. More than 3000 new events, mostly located on the main shock fault, were detected to define the spatial‐temporal evolution of micro‐seismicity. The foreshock sequence was active northwest of the Mw 6.3 hypocenter in January, then migrated toward it at a speed of ~0.5 km/day in middle of February. At that time, in a ~4 km2 patch close to the main shock nucleation point, the cumulative number of earthquakes gradually increased until the Mw 6.3 event. This patch, characterized by a low b‐value, played a key role in controlling the preparation stage to the 2009 L'Aquila main rupture.
Electron kappa distribution and quasi‐thermal noise
Authors: Yoon Peter H.
Published: August 2014

Spacecraft measurements of charged particles in the solar wind show that their velocity distributions deviate from thermal Maxwellian model, having energetic components with quasi‐scale‐free power law velocity dependence, f ∼ v−α, in the high‐velocity range. It is customary to model such a feature by means of the kappa distribution, first introduced in the 1960s to empirically fit the data, but attempts have been made to understand the kappa distribution in terms of nonextensive statistical mechanics. A recent series of papers explore an alternative model, which may be interrelated with the nonextensive thermostatistical concept. According to the model, the electron kappa distribution is understood as a self‐consistent steady state solution of the weak turbulence equation in which the electrons and electrostatic Langmuir turbulence are in dynamic equilibrium state. These papers also compared the theoretical kappa parameter with observations of quiet time solar wind electrons near 1 AU. However, the electrostatic Langmuir turbulence, also known as the quasi‐thermal noise, requires a more in‐depth analysis. The present paper extends the recent theory by including a discussion of electrostatic fluctuations in greater detail, thus bringing the theory to a full closure.
Quantitative estimate of heat flow from a mid‐ocean ridge axial valley, Raven field, Juan de Fuca Ridge: Observations and inferences
Authors: Salmi Marie S. , Johnson H. Paul , Tivey Maurice A. , Hutnak Michael
Published: August 2014

A systematic heat flow survey using thermal blankets within the Endeavour segment of the Juan de Fuca Ridge axial valley provides quantitative estimates of the magnitude and distribution of conductive heat flow at a mid‐ocean ridge, with the goal of testing current models of hydrothermal circulation present within newly formed oceanic crust. Thermal blankets were deployed covering an area of 700 by 450 m in the Raven Hydrothermal vent field area located 400 m north of the Main Endeavour hydrothermal field. A total of 176 successful blanket deployment sites measured heat flow values that ranged from 0 to 31 W m−2. Approximately 53% of the sites recorded values lower than 100 mW m−2, suggesting large areas of seawater recharge and advective extraction of lithospheric heat. High heat flow values were concentrated around relatively small “hot spots.” Integration of heat flow values over the Raven survey area gives an estimate of conductive heat output of 0.3 MW, an average of 0.95 W m−2, over the survey area. Fluid circulation cell dimensions and scaling equations allow calculation of a Rayleigh number of approximately 700 in Layer 2A. The close proximity of high and low heat flow areas, coupled with previous estimates of surficial seafloor permeability, argues for the presence of small‐scale hydrothermal fluid circulation cells within the high‐porosity uppermost crustal layer of the axial seafloor.
Impact of various observing systems on weather analysis and forecast over the Indian region
Authors: Singh Randhir , Ojha Satya P. , Kishtawal C. M. , Pal P. K.
Published: August 2014

To investigate the potential impact of various types of data on weather forecast over the Indian region, a set of data‐denial experiments spanning the entire month of July 2012 is executed using the Weather Research and Forecasting (WRF) model and its three‐dimensional variational (3DVAR) data assimilation system. The experiments are designed to allow the assessment of mass versus wind observations and terrestrial versus space‐based instruments, to evaluate the relative importance of the classes of conventional instrument such as radiosonde, and finally to investigate the role of individual spaceborne instruments. The moist total energy norm is used for validation and forecast skill assessment. The results show that the contribution of wind observations toward error reduction is larger than mass observations in the short range (48 h) forecast. Terrestrial‐based observations generally contribute more than space‐based observations except for the moisture fields, where the role of the space‐based instruments becomes more prevalent. Only about 50% of individual instruments are found to be beneficial in this experiment configuration, with the most important role played by radiosondes. Thereafter, Meteosat Atmospheric Motion Vectors (AMVs) (only for short range forecast) and Special Sensor Microwave Imager (SSM/I) are second and third, followed by surface observations, Sounder for Probing Vertical Profiles of Humidity (SAPHIR) radiances and pilot observations. Results of the additional experiments of comparative performance of SSM/I total precipitable water (TPW), Microwave Humidity Sounder (MHS), and SAPHIR radiances indicate that SSM/I is the most important instrument followed by SAPHIR and MHS for improving the quality of the forecast over the Indian region. Further, the impact of single SAPHIR instrument (onboard Megha‐Tropiques) is significantly larger compared to three MHS instruments (onboard NOAA‐18/19 and MetOp‐A).
Distribution and activity of ice wedges across the forest‐tundra transition, western Arctic Canada
Authors: Kokelj S. V. , Lantz T. C. , Wolfe S. A. , Kanigan J. C. , Morse P. D. , Coutts R. , Molina‐Giraldo N. , Burn C. R.
Published: August 2014

Remote sensing, regional ground temperature and ground ice observations, and numerical simulation were used to investigate the size, distribution, and activity of ice wedges in fine‐grained mineral and organic soils across the forest‐tundra transition in uplands east of the Mackenzie Delta. In the northernmost dwarf‐shrub tundra, ice wedge polygons cover up to 40% of the ground surface, with the wedges commonly exceeding 3 m in width. The largest ice wedges are in peatlands where thermal contraction cracking occurs more frequently than in nearby hummocky terrain with fine‐grained soils. There are fewer ice wedges, rarely exceeding 2 m in width, in uplands to the south and none have been found in mineral soils of the tall‐shrub tundra, although active ice wedges are found there throughout peatlands. In the spruce forest zone, small, relict ice wedges are restricted to peatlands. At tundra sites, winter temperatures at the top of permafrost are lower in organic than mineral soils because of the shallow permafrost table, occurrence of phase change at 0°C, and the relatively high thermal conductivity of icy peat. Due to these factors and the high coefficient of thermal contraction of frozen saturated peat, ice wedge cracking and growth is more common in peatlands than in mineral soil. However, the high latent heat content of saturated organic active layer soils may inhibit freezeback, particularly where thick snow accumulates, making the permafrost and the ice wedges in spruce forest polygonal peatlands susceptible to degradation following alteration of drainage or climate warming.
Two‐Dimensional Soft Nanomaterials: A Fascinating World of Materials
Authors: Zhuang Xiaodong , Mai Yiyong , Wu Dongqing , Zhang Fan , Feng Xinliang
Published: August 2014

The discovery of graphene has triggered great interest in two‐dimensional (2D) nanomaterials for scientists in chemistry, physics, materials science, and related areas. In the family of newly developed 2D nanostructured materials, 2D soft nanomaterials, including graphene, BxCyNz nanosheets, 2D polymers, covalent organic frameworks (COFs), and 2D supramolecular organic nanostructures, possess great advantages in light‐weight, structural control and flexibility, diversity of fabrication approaches, and so on. These merits offer 2D soft nanomaterials a wide range of potential applications, such as in optoelectronics, membranes, energy storage and conversion, catalysis, sensing, biotechnology, etc. This review article provides an overview of the development of 2D soft nanomaterials, with special highlights on the basic concepts, molecular design principles, and primary synthesis approaches in the context.
Hydrogels and Scaffolds for Immunomodulation
Authors: Singh Ankur , Peppas Nicholas A.
Published: August 2014

For over two decades, immunologists and biomaterials scientists have co‐existed in parallel world with the rationale of understanding the molecular profile of immune responses to vaccination, implantation, and treating incurable diseases. Much of the field of biomaterial‐based immunotherapy has relied on evaluating model antigens such as chicken egg ovalbumin in mouse models but their relevance to humans has been point of much discussion. Nevertheless, such model antigens have provided important insights into the mechanisms of immune regulation and served as a proof‐of‐concept for plethora of biomaterial‐based vaccines. After years of extensive development of numerous biomaterials for immunomodulation, it is only recently that an experimental scaffold vaccine implanted beneath the skin has begun to use the human model to study the immune responses to cancer vaccination by co‐delivering patient‐derived tumor lysates and immunomodulatory proteins. If successful, this scaffold vaccine will change the way we approached untreatable cancers, but more importantly, will allow a faster and more rational translation of therapeutic regimes to other cancers, chronic infections, and autoimmune diseases. Most materials reviews have focused on immunomodulatory adjuvants and micro‐nano‐particles. Here we provide an insight into emerging hydrogel and scaffold based immunomodulatory approaches that continue to demonstrate efficacy against immune associated diseases.
Daily environmental differences in blood pressure and heart rate variability in healthy premenopausal women
Authors: James Gary D. , Bovbjerg Dana H. , Hill Leah A.
Published: August 2014

Objectives

As daily environments change, behavior and activity also change and as blood pressure (BP) and heart rate (HR) are allostatically tied to these factors, one might expect that environments that elicit the greatest behavioral/activity variation should also evince the highest BP and HR variability [standard deviation (SD) or coefficient of variation (CV)]. The purpose of this study was to evaluate this premise.

Methods

Two hundred and six women (age = 37.6 ± 9.1 years) wore an ambulatory BP monitor on a midweek workday. All worked in clerical, technical, or professional positions. Ambulatory BP and HR Means, SDs and CVs at work (11 AM–3 PM), home (∼6–10 PM) and during sleep (∼10 PM–6 AM) were compared using repeated measures ANCOVA.

Results

Mean BP and HR decreased from work and home to sleep [121 ± 11, 120 ± 11 vs. 107 ± 12 systolic; 82 ± 10, 80 ± 11 vs. 66 ± 11 diastolic; 79 ± 12, 80 ± 12 vs. 68 ± 11 HR (all P < 0.001)], while the CV of systolic and diastolic BP increased [0.06 ± 0.02, 0.07 ± 0.02 vs. 0.08 ± 0.03 systolic; 0.09 ± 0.03, 0.10 ± 0.04 vs. 0.12 ± 0.05 diastolic (P < 0.001)]. The HR SD decreased during sleep [8.1 ± 3.8, 8.2 ± 3.8 vs. 6.9 ± 3.2 (P < 0.001)].

Conclusions

HR variability follows the expected variability pattern with behavior and activity, whereas BP does not. Am. J. Hum. Biol. 27:136–138, 2015. © 2014 Wiley Periodicals, Inc.
Gold(I)‐Catalyzed Diazo Coupling: Strategy towards Alkene Formation and Tandem Benzannulation
Authors: Zhang Daming , Xu Guangyang , Ding Dong , Zhu Chenghao , Li Jian , Sun Jiangtao
Published: August 2014

A gold(I)‐catalyzed cross‐coupling of diazo compounds to afford tetrasubstituted alkenes has been developed by taking advantage of a trivial electronic difference between two diazo substrates. A N‐heterocyclic‐carbene‐derived gold complex is the most effective catalyst for this transformation. Based on this new strategy, a gold(I)‐initiated benzannulation has been achieved through a tandem reaction involving a diazo cross‐coupling, 6π electrocyclization, and oxidative aromatization.
Photocatalytic Synthesis of Dihydrobenzofurans by Oxidative [3+2] Cycloaddition of Phenols
Authors: Blum Travis R. , Zhu Ye , Nordeen Sarah A. , Yoon Tehshik P.
Published: August 2014

We report a protocol for oxidative [3+2] cycloadditions of phenols and alkenes applicable to the modular synthesis of a large family of dihydrobenzofuran natural products. Visible‐light‐activated transition metal photocatalysis enables the use of ammonium persulfate as an easily handled, benign terminal oxidant. The broad range of organic substrates that are readily oxidized by photoredox catalysis suggests that this strategy may be applicable to a variety of useful oxidative transformations.
Highly Diastereoselective and Enantiospecific Allylation of Ketones and Imines Using Borinic Esters: Contiguous Quaternary Stereogenic Centers
Authors: Chen Jack L.‐Y. , Aggarwal Varinder K.
Published: August 2014

3,3‐Disubstituted allylic boronic esters are not sufficiently reactive to react with ketones and imines. However, they can be converted into the corresponding borinic esters by the sequential addition of nBuLi and TFAA. These reactive intermediates possess the perfect balance between reactivity and configurational stability. Their enhanced reactivity allows the highly selective allylation of both ketones and ketimines, and facile access to adjacent quaternary stereocenters with full stereocontrol. The versatility of the methodology is demonstrated in the construction of all possible stereoisomers of a quaternary‐quaternary motif and by the allylation of the heterocycles, dihydroisoquinoline and indole.
Arylacetylene‐Substituted Naphthalene Diimides with Dual Functions: Optical Waveguides and n‐Type Semiconductors
Authors: Li Yonghai , Zhang Guanxin , Zhang Wei , Wang Jianguo , Chen Xin , Liu Zitong , Yan Yongli , Zhao Yongsheng , Zhang Deqing
Published: August 2014

New arylacetylene‐substituted naphthalene diimides (NDIs) 1–6, with both light‐emitting and semiconducting functions, are reported. Among them, the crystal structure of 1 was determined. On the basis of their reduction potentials and thin‐film absorption spectra, the HOMO/LUMO energies of these modified NDIs were estimated. The results reveal that their HOMO/LUMO energies are slightly affected by the flanking aryl groups. The emission colors of these NDIs vary from green to red, and interestingly, they show aggregation‐induced emission enhancement behavior with fluorescence quantum yields reaching 9.86 % in the solid state. Microrods of 1, 3, and 5 show typical optical wave‐guiding behavior with relatively low optical‐loss coefficients. Organic field‐effect transistors with thin films of these NDIs were fabricated with conventional techniques. The results indicate that thin films of 2, 4, and 6, with long and branched alkyl chains, show air‐stable n‐type semiconducting properties with electron mobilities of up to 0.035 cm2 V−1 s−1 after thermal annealing, whereas 1, 3, and 5, with short alkyl chains, behave as n‐type semiconductors under a nitrogen atmosphere with electron mobilities of up to 0.075 cm2 V−1 s−1 after thermal annealing.
Inhomogeneous influence of the Atlantic warm pool on United States precipitation
Authors: Liu Hailong , Wang Chunzai , Lee Sang‐Ki , Enfield David
Published: August 2014

On interannual time scales, the warming of the Atlantic warm pool (AWP) is associated with a tripole sea surface temperature (SST) pattern in the North Atlantic and leads to more rainfall in the central and eastern US. On decadal‐to‐multidecadal time scales, the AWP warming corresponds to a basin‐wide warming pattern and results in less precipitation in the central and eastern US. The inhomogeneous relationship between the AWP warming and US rainfall on different time scales is largely due to the sign of mid‐latitude SST anomaly. The negative mid‐latitude SST anomaly associated with the tripole pattern may enhance the low sea level pressure over the northeastern North American continent and also enhance the barotropic response there of the AWP‐induced barotropic Rossby wave. This strengthened low pressure system, which is not exhibited when the warming is basin‐wide, results in a different moisture transport variation and thus the rainfall pattern over the United States.
Direct effect of lower‐tropospheric diabatic heating on surface wind over the equatorial Pacific
Authors: Li Lijuan , Wang Bin , Zhou Tianjun
Published: August 2014

The direct effect of lower‐tropospheric diabatic heating (DH) on surface circulation over the equatorial Pacific is revealed using the theoretical analysis and three atmospheric general circulation model (AGCM) simulations, only differing their moist processes. The AGCM results suggest that the insensitivity of surface wind to DH in the middle and high levels is closely associated with the vertical disagreement of DH between the layers below and above 925 hPa over the equatorial Pacific.
Towards an aerosol classification scheme for future EarthCARE lidar observations and implications for research needs
Authors: Groß S. , Freudenthaler V. , Wirth M. , Weinzierl B.
Published: August 2014

Owing to the high variability of aerosols, and their different impact on the Earth's climate system, aerosol type classification from satellite measurements is of high importance. Polarization sensitive lidar measurements on board the future Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) satellite mission will provide information to distinguish different aerosol types. We analyze whether former classification schemes based on lidar measurements at 532 nm are applicable to EarthCARE measurements at 355 nm. We compare coordinated lidar measurements at both wavelengths performed during five field experiments; adapt thresholds for aerosol classification with future spaceborne lidar measurements and identify limitations of the current state of knowledge.
Friction in mid‐latitude cyclones: an Ekman‐PV mechanism
Authors: Boutle I. A. , Belcher S. E. , Plant R. S.
Published: August 2014

The mechanism by which the atmospheric boundary layer reduces the intensity of mid‐latitude cyclones is investigated. It is demonstrated that two alternative theories, Ekman pumping and the baroclinic potential vorticity (PV) mechanism, in fact act in union to maximize the spin‐down. Ekman pumping aids the ventilation of PV from the boundary layer, and shapes the resulting PV anomaly into one of increased static stability. PV inversion techniques are used to demonstrate how this anomaly reduces the coupling between the upper‐ and lower‐levels within the cyclone, reducing the growth rate.
Experimental evidence needed to demonstrate inter‐ and trans‐generational effects of ancestral experiences in mammals
Authors: Dias Brian G. , Ressler Kerry J.
Published: August 2014

Environmental factors routinely influence an organism's biology. The inheritance or transmission of such influences to descendant generations would be an efficient mode of information transfer across generations. The developmental stage at which a specific environment is encountered by the ancestral generation, and the number of generations over which information about that environment is registered, determines an inter‐ vs. trans‐generational effect of ancestral influence. This commentary will outline the distinction between these influences. While seductive in principle, inter‐ and trans‐generational inheritance in mammals is a hotly debated area of research inquiry. We present constructive criticism of such inheritance, and suggest potential experimental avenues for reconciliation. Finally, epigenetic mechanisms present an avenue for gene regulation that is dynamic. We briefly discuss how such malleability affords the potential for a reversal of any detrimental environmental influences that might have adversely impacted ancestral or descendant generations.
Silencing of TERT decreases levels of miR‐1, miR‐21, miR‐29a and miR‐208a in cardiomyocytes
Authors: Drevytska T. I. , Nagibin V. S. , Gurianova V. L. , Kedlyan V. R. , Moibenko A. A. , Dosenko V. E.
Published: August 2014

To test the hypothesis that telomerase reverse transcriptase (TERT) as an RNA‐dependent RNA polymerase could be involved in the amplification of microRNA (miRNA), we have determined the levels of immature and mature miRNA in cultured neonatal rat cardiomyocytes, during the silencing of TERT by siRNA. The silencing of the TERT gene led to the reduction of both telomerase activity and the TERT mRNA expression when compared with scrambled RNA. TERT gene silencing resulted in the decrement of three studied mature miRNAs levels: miRNA‐21, miRNA‐29a and miRNA‐208a when compared with scrambled RNA; but miRNA‐1, it was not changed significantly. At the same time, levels of immature miRNA‐1 and miRNA‐208a were not changed, although the levels of immature miRNA‐29a and pri‐miRNA‐1 were decreased. The data obtained allow us to permit that TERT is a genome‐independent source of mature miRNA, and the changes in telomerase activity can significantly influence the level of miRNA in cardiomyocytes. Copyright © 2014 John Wiley & Sons, Ltd.
Predictors of post‐sentence mental health service use in a population cohort of first‐time adult offenders in Western Australia
Authors: Sodhi‐Berry Nita , Knuiman Matthew , Preen David B. , Alan Janine , Morgan Vera A.
Published: August 2014

Background

Little is known about whether or how offenders use mental health services after sentence completion.

Aim

This study aimed to determine the likelihood of such service use by adult (18–44 years) first‐time offenders up to 5 years after sentence completion and possible predictor variables.

Methods

Pre‐sentence and post‐sentence mental health service use was obtained from whole‐population linked administrative data on 23,661 adult offenders. Cox proportional hazard models were used to determine which socio‐demographic, offending and pre‐sentence health service variables were associated with such post‐sentence service use.

Results

The estimated 5‐year probability of any post‐sentence mental health service use was 12% for offenders who had not previously used such services, but still only 42% for those who had. For the latter, best predictors of post‐sentence use were past psychiatric diagnosis and history of self‐harm; history of self‐harm also predicted post‐sentence use among new mental health services users and so also did past physical illness. Indigenous offenders had a greater likelihood of service use for any mental disorder or for substance use disorders than non‐Indigenous offenders, irrespective of pre‐sentence use. Among those with pre‐sentence service contact, imprisoned offenders were less likely to use mental health services after sentence than those under community penalties; in its absence, socio‐economic disadvantage and geographic accessibility were associated with greater likelihood of post‐sentence use.

Conclusions

Our findings highlight the discontinuity of mental healthcare for most sentenced offenders, but especially prisoners, and suggest a need for better management strategies for these vulnerable groups with mental disorders. Copyright © 2014 John Wiley & Sons, Ltd.
Synergetic Catalytic Effects in Tri‐Component Mesostructured Ru–Cu–Ce Oxide Nanocomposite in CO Oxidation
Authors: Cui Xiangzhi , Wang Yongxia , Chen Lisong , Shi Jianlin
Published: August 2014

This work focuses on probing the synergetic catalytic effects in mesostructured tri‐component Ru–Cu–Ce oxides in CO oxidation reaction. The crystallized nanocomposites with RuO2 and CuO nanoparticles dispersed homogeneously in the pore network of mesoporous CeO2 were synthesized by the nanocasting replication method. The greatly enhanced catalytic activity was achieved by CuO incorporating in mesoporous CeO2, and further by RuO2 incorporating in the mesostructure of CuO/CeO2. Two types of synergetic catalytic mechanisms have been preliminarily proposed to be copresent in the system: CeO2 activation by CuO through generating oxygen vacancies at CeO2/CuO interface and the CeO2 surface nearby, which consequently activate the oxygen species (O*) and enhance the CO oxidation activity of the bi‐metal CuCe oxide, and the simultaneous adsorption of CO molecules and their activation in parallel on the active surface of RuO2, which results in further elevated catalytic activity.
Catalysis by Dynamically Formed Defects in a Metal–Organic Framework Structure: Knoevenagel Reaction Catalyzed by Copper Benzene‐1,3,5‐tricarboxylate
Authors: Položij Miroslav , Rubeš Miroslav , Čejka Jiří , Nachtigall Petr
Published: August 2014

The high catalytic activity and selectivity of the metal–organic framework (MOF) copper benzene‐1,3,5‐tricarboxylate (CuBTC) that are observed experimentally in the Knoevenagel reaction are explained on the basis of computational investigations by employing a periodic model and density functional theory. Three factors are responsible for the unusually high activity of CuBTC: One, CuBTC can act as a base, and the active methylene reactant is deprotonated, whereas a temporary defect in the framework is formed; two, the thus‐formed defect, a Brønsted acid site, simultaneously activates the aldehyde; three, the reaction takes place on two adjacent Cu2+ sites (Lewis acid sites) that are separated by 8.2 Å. The results reported herein show the great versatility of the CuBTC MOF catalyst, including its amphiphilic character and the concerted effect of nearby framework metal cations.
Electrochemically Controlled One‐Electron Oxidation Coupled to Consecutive Hydrogen Atom Transfer of Caffeine
Authors: Chan Kwok Kiong , Ganguly Rakesh , Li Yongxin , Webster Richard D.
Published: August 2014

Caffeine (CAF) undergoes a one‐electron oxidation in acetonitrile to form a cation radical, with variable scan rate CV experiments indicating that the lifetime of the cation radical improves as the trace water content of the solvent is decreased. Electrochemical oxidation (and chemical oxidation with NOSbF6) of CAF in CH3CN leads to the generation of the protonated CAF cation as the long‐term product in high yield, whose structure is confirmed by single‐crystal X‐ray crystallography and NMR spectroscopy. The protonated cation is able to be electrochemically reduced back to CAF under electrolysis conditions. The formation of the protonated cation involves the initial one‐electron oxidation of CAF to form the cation radical, which undergoes a hydrogen atom abstraction reaction. Digital simulations of the CV data show that the rate and equilibrium constants for the hydrogen atom abstraction step are kf=1.0×102 L mol−1 s−1 and Keq=1.0×102.
Vernier‐Templated Synthesis, Crystal Structure, and Supramolecular Chemistry of a 12‐Porphyrin Nanoring
Authors: Kondratuk Dmitry V. , Sprafke Johannes K. , O'Sullivan Melanie C. , Perdigao Luis M. A. , Saywell Alex , Malfois Marc , O'Shea James N. , Beton Peter H. , Thompson Amber L. , Anderson Harry L.
Published: August 2014

Vernier templating exploits a mismatch between the number of binding sites in a template and a reactant to direct the formation of a product that is large enough to bind several template units. Here, we present a detailed study of the Vernier‐templated synthesis of a 12‐porphyrin nanoring. NMR and small‐angle X‐ray scattering (SAXS) analyses show that Vernier complexes are formed as intermediates in the cyclo‐oligomerization reaction. UV/Vis/NIR titrations show that the three‐component assembly of the 12‐porphyrin nanoring figure‐of‐eight template complex displays high allosteric cooperativity and chelate cooperativity. This nanoring–template 1:2 complex is among the largest synthetic molecules to have been characterized by single‐crystal analysis. It crystallizes as a racemate, with an angle of 27° between the planes of the two template units. The crystal structure reveals many unexpected intramolecular CH⋅⋅⋅N contacts involving the tert‐butyl side chains. Scanning tunneling microscopy (STM) experiments show that molecules of the 12‐porphyrin template complex can remain intact on the gold surface, although the majority of the material unfolds into the free nanoring during electrospray deposition.
One Ligand in Dual Roles: Self‐Assembly of a Bis‐Rhomboidal‐Shaped, Three‐Dimensional Molecular Wheel
Authors: Lu Xiaocun , Li Xiaopeng , Guo Kai , Wang Jing , Huang Mingjun , Wang Jin‐Liang , Xie Ting‐Zheng , Moorefield Charles N. , Cheng Stephen Z. D. , Wesdemiotis Chrys , Newkome George R.
Published: August 2014

A facile high yield, self‐assembly process that leads to a terpyridine‐based, three‐dimensional, bis‐rhomboidal‐shaped, molecular wheel is reported. The desired coordination‐driven supramolecular wheel involves eight structurally distorted tristerpyridine (tpy) ligands possessing a 60° angle between the adjacent tpy units and twelve Zn2+ ions. The tpy ligand plays dual roles in the self‐assembly process: two are staggered at 180° to create the internal hub, while six produce the external rim. The wheel can be readily generated by mixing the tpy ligand and Zn2+ in a stoichiometric ratio of 2:3; full characterization is provided by ESI‐MS, NMR spectroscopy, and TEM imaging.
Novel Organocatalytic Activation of Unmodified Morita–Baylis–Hillman Alcohols for the Synthesis of Bicyclic α‐Alkylidene‐Ketones
Authors: Stiller Julian , Kowalczyk Dorota , Jiang Hao , Jørgensen Karl Anker , Albrecht Łukasz
Published: August 2014

The organocatalytic activation of Morita–Baylis–Hillman alcohols via H‐bonding‐iminium‐ion formation is demonstrated for the first time. This activation strategy enables the Morita‐Baylis–Hillman alcohols to undergo a formal SN2′ reaction. In combination with the well‐established enamine reactivity, this creates a new reactivity pattern. The application of this new activation mode for the synthesis of bicyclic α‐alkylidene‐ketones is demonstrated. The developed reaction sequence proceeds efficiently affording nature‐inspired target products with four contiguous stereogenic centers in a highly stereoselective manner.
Impact of Magnesium(II) on Beryllium Fluorides in Solutions Studied by 19F NMR Spectroscopy
Authors: Liu Yixiang , Mao Xian , Liu Maili , Jiang Ling
Published: August 2014

Beryllium fluorides are widely used in protein phosphorylation studies to get stable transition state analogs or near attack conformers, which has attracted much attention. BeF3− is one of the optimal phosphoryl (PO3−) analogs for its identical geometry and charge, and Mg2+ naturally participates in the phosphoryl binding in biological systems. In solutions, BeF3− coexists with other beryllium fluorides (BeF42−, BeF2 and BeF+) and magnesium fluorides, and there are equilibriums between these species. In this article, 19F NMR spectroscopy was applied to the investigation of the impact of magnesium(II) on beryllium fluorides. It has been found that when Mg2+ was introduced into the solutions, the chemical shifts, the intensities and the line widths of 19F signals of various beryllium fluoride complexes were changed. After ionic strength correction, these effects were remarkable only for BeF42− and BeF3−, especially BeF42−, when the concentration of the fluoride ion is relatively low. Mechanism of the effects is proposed which involves ion pair formation between Mg2+ and beryllium fluorides.
Chincona Alkaloid‐Catalyzed Enantioselective Trifluoromethylthiolation of Oxindoles
Authors: Yang Tao , Shen Qilong , Lu Long
Published: August 2014

An organocatalytic asymmetric trifluoromethylthiolation of 3‐aryl or 3‐alkyloxindoles employing a trifluoromethyl‐substituted thioperoxide as the electrophilic trifluoromethylthiolating reagent was described. Reactions occurred in good to excellent enantioselectivities to generate oxindoles with a SCF3‐substituted quaternary chiral center.
Aniline Induced Domino Ring Contraction Process on the Rim of an Open‐Cage Fullerene with Carbonyl, Imino and Iactone Moieties
Authors: Liu Shuming , Gan Liangbing
Published: August 2014

Functional groups on the rim of open‐cage fullerenes usually exhibit different reactivity from those in classical organic molecules due to the unique spherical structure of fullerenes. The present work shows a sequence of lactone opening, imino hydrolysis, aminal formation and imine formation processes during the reaction of aniline with the open‐cage compound 1 with functional groups including lactone on the rim of the orifice. Single crystal X‐ray diffraction analysis confirmed the structure of the product.
Bio‐inspired Step‐Economical, Redox‐Economical and Protecting‐Group‐Free Enantioselective Total Syntheses of (−)‐Chaetominine and Analogues
Authors: Luo Shi‐Peng , Peng Qi‐Long , Xu Chu‐Pei , Wang Ai‐E , Huang Pei‐Qiang
Published: August 2014

Full details of the enantioselective four‐step and five‐step total syntheses of (−)‐chaetominine from D‐Trp and L‐Trp are described. Featuring an oxidative double cyclization reaction, and tandem C14 epimerization‐lactamization reactions as key steps, the method provides a rapid access to (−)‐chaetominine (6a) and analogues. The total syntheses of (−)‐chaetominine (6a) are so far the most concise and efficient. Through comprehensive investigation, the stereochemical requirements for the double cyclization reaction were revealed, and the confusion regarding physicochemical properties of this natural product was clarified. Moreover, short pathways to complexity generation, a scenarios revealed for the biosynthesis of fungal peptidyl alkaloid multi‐cyclic scaffolds, have been validated through the chemical synthesis. On the basis of these findings, a plausible biosynthetic pathway for (−)‐chaetominine (6a) was suggested.
Cu‐Promoted Oxidative Trifluoromethylation of Terminal Alkynes with Difluoromethylene Phosphobetaine
Authors: Deng Xiaoyun , Lin Jinhong , Zheng Jian , Xiao Jichang
Published: August 2014

Difluoromethylene phosphobetaine (Ph3P+CF2CO2−, PDFA), a known difluorocarbene reagent, was found to be able to efficiently trifluoromethylate terminal alkynes in the presence of Cu(I) and potassium fluoride. The transformation proceeded smoothly to afford the corresponding trifluoromethylated acetylenes in moderate yields.
Impact of state‐specific Medicaid reimbursement and eligibility policies on receipt of cancer screening
Authors: Halpern Michael T. , Romaire Melissa A. , Haber Susan G. , Tangka Florence K. , Sabatino Susan A. , Howard David H.
Published: August 2014

BACKGROUND

Although state Medicaid programs cover cancer screening, Medicaid beneficiaries are less likely to be screened for cancer and are more likely to present with tumors of an advanced stage than are those with other insurance. The current study was performed to determine whether state Medicaid eligibility and reimbursement policies affect the receipt of breast, cervical, and colon cancer screening among Medicaid beneficiaries.

METHODS

Cross‐sectional regression analyses of 2007 Medicaid data from 46 states and the District of Columbia were performed to examine associations between state‐specific Medicaid reimbursement/eligibility policies and receipt of cancer screening. The study sample included individuals aged 21 years to 64 years who were enrolled in fee‐for‐service Medicaid for at least 4 months. Subsamples eligible for each screening test were: Papanicolaou test among 2,136,511 patients, mammography among 792,470 patients, colonoscopy among 769,729 patients, and fecal occult blood test among 753,868 patients. State‐specific Medicaid variables included median screening test reimbursement, income/financial asset eligibility requirements, physician copayments, and frequency of eligibility renewal.

RESULTS

Increases in screening test reimbursement demonstrated mixed associations (positive and negative) with the likelihood of receiving screening tests among Medicaid beneficiaries. In contrast, increased reimbursements for office visits were found to be positively associated with the odds of receiving all screening tests examined, including colonoscopy (odds ratio [OR], 1.07; 95% confidence interval [95% CI], 1.06‐1.08), fecal occult blood test (OR, 1.09; 95% CI, 1.08‐1.10), Papanicolaou test (OR, 1.02; 95% CI, 1.02‐1.03), and mammography (OR, 1.02; 95% CI, 1.02‐1.03). Effects of other state‐specific Medicaid policies varied across the screening tests examined.

CONCLUSIONS

Increased reimbursement for office visits was consistently associated with an increased likelihood of being screened for cancer, and may be an important policy tool for increasing screening among this vulnerable population. Cancer 2014;120:3016–3024. © 2014 American Cancer Society.
Serum‐based miRNAs in the prediction and detection of recurrence in melanoma patients
Authors: Fleming Nathaniel H. , Zhong Judy , da Silva Inês Pires , Vega‐Saenz de Miera Eleazar , Brady Bobbi , Han Sung Won , Hanniford Doug , Wang Jinhua , Shapiro Richard L. , Hernando Eva , Osman Iman
Published: August 2014

BACKGROUND

Identification of primary melanoma patients at the highest risk of recurrence remains a critical challenge, and monitoring for recurrent disease is limited to costly imaging studies. We recently reported our array‐based discovery of prognostic serum miRNAs in melanoma. In the current study, we examined the clinical utility of these serum‐based miRNAs for prognosis as well as detection of melanoma recurrence.

METHODS

Serum levels of 12 miRNAs were tested using qRT‐PCR at diagnosis in 283 melanoma patients (training cohort, n = 201; independent validation, n = 82; median follow‐up, 68.8 months). A refined miRNA signature was chosen and evaluated. We also tested the potential clinical utility of the miRNAs in early detection and monitoring of recurrence using multiple longitudinal samples (pre‐ and postrecurrence) in a subset of 82 patients (n = 225). In addition, we integrated our miRNA signature with publicly available Cancer Genome Atlas data to examine the relevance of these miRNAs to melanoma biology.

RESULTS

Four miRNAs (miR‐150, miR‐30d, miR‐15b, and miR‐425) in combination with stage separated patients by recurrence‐free survival (RFS) and overall survival (OS) and improved prediction of recurrence over stage alone in both the training and validation cohorts (training RFS and OS, P < .001; validation RFS, P < .001; OS, P = .005). Serum miR‐15b levels significantly increased over time in recurrent patients (P < .001), adjusting for endogenous controls as well as age, sex, and initial stage. In nonrecurrent patients, miR‐15b levels were not significantly changed with time (P =.17).

CONCLUSIONS

Data demonstrate that serum miRNAs can improve melanoma patient stratification over stage and support further testing of miR‐15b to guide patient surveillance. Cancer 2015;121:51–59. © 2014 American Cancer Society.
Morphological parameters able to predict BRAFV600E‐mutated malignancies on thyroid fine‐needle aspiration cytology: Our institutional experience
Authors: Rossi Esther Diana , Bizzarro Tommaso , Martini Maurizio , Capodimonti Sara , Fadda Guido , Larocca Luigi Maria , Schmitt Fernando
Published: August 2014

BACKGROUND

The BRAFV600E mutation is the most common diagnostic/prognostic marker in papillary thyroid carcinoma (PTC). Its evaluation is typically performed with DNA‐based techniques; nonetheless, a few articles have recently proposed the morphological prediction of BRAFV600E in histological PTCs. We investigated this morphological parameter in our cytological series.

METHODS

We re‐analyzed all 72 cytohistological samples diagnosed as positive for malignancy (favoring PTC) on fine‐needle aspiration cytology from January 2012 to December 2013. We included 22 male patients and 50 female patients. The cytological cases were processed with liquid‐based cytology. We performed molecular analysis and immunocytochemistry for the VE1 BRAFV600E antibody.

RESULTS

We reported 47 mutated cases and 25 wild‐type (WT) cases with 100% cytohistological concordance. The cytological evaluations revealed plump cells (abundant eosinophilic cytoplasm and PTC nuclei) in all 47 mutated cases, with only 6 having a focal plump cell component (≤20% cells). Furthermore, 5 of the 25 WT cases showed focal plump cells. A distinctive sickle nuclear shape was found only in the mutated cases. VE1 yielded 100% positivity for all 24 mutated cases that were tested, including 3 cases with focal plump cells.

CONCLUSIONS

We demonstrated that the BRAFV600E mutation might be predicted in cytological samples on the basis of some specific morphological features. Although the detection of plump cells (mainly focal) was also observed in WT cases, the detection of sickle‐shaped nuclei provided the highest specificity and sensitivity as a predictive mutational parameter. These morphological features might be a valid tool for selecting cases for molecular analysis. Cancer (Cancer Cytopathol) 2014;122:883–891. © 2014 American Cancer Society.
In Situ Encapsulation of Germanium Clusters in Carbon Nanofibers: High‐Performance Anodes for Lithium‐Ion Batteries
Authors: Wang Wei , Xiao Ying , Wang Xia , Liu Bing , Cao Minhua
Published: August 2014

Alloyed anode materials for lithium‐ion batteries (LIBs) usually suffer from considerable capacity losses during charge–discharge process. Herein, in situ‐grown germanium clusters are homogeneously encapsulated into porous nitrogen‐doped carbon nanofibers (N‐CNFs) to form Ge/N‐CNFs hybrids, using a facile electrospinning method followed by thermal treatment. When used as anode in LIBs, the Ge/N‐CNFs hybrids exhibit excellent lithium storage performance in terms of specific capacity, cycling stability, and rate capability. The excellent electrochemical properties can be attributed to the unique structural features: the distribution of the germanium clusters, porous carbon nanofibers, and GeN chemical bonds all contribute to alleviating the large volume changes of germanium during the discharge–charge process, while at same time the unique porous N‐CNFs not only increase the contact area between the electrode and the electrolyte, but also the conductivity of the hybrid.
Multiple Cathodic Reaction Mechanisms in Seawater Cathodic Biofilms Operating in Sediment Microbial Fuel Cells
Authors: Babauta Jerome T. , Hsu Lewis , Atci Erhan , Kagan Jeff , Chadwick Bart , Beyenal Haluk
Published: August 2014

In this study, multiple reaction mechanisms in cathodes of sediment microbial fuel cells (SMFCs) were characterized by using cyclic voltammetry and microelectrode measurements of dissolved oxygen and pH. The cathodes were acclimated in SMFCs with sediment and seawater from San Diego Bay. Two limiting current regions were observed with onset potentials of approximately +400 mVAg/AgCl for limiting current I and −120 mVAg/AgCl for limiting current II. The appearance of two catalytic waves suggests that multiple cathodic reaction mechanisms influence cathodic performance. Microscale oxygen concentration measurements showed a zero surface concentration at the electrode surface for limiting current II but not for limiting current I, which allowed us to distinguish limiting current II as the conventional oxygen reduction reaction and limiting current I as a currently unidentified cathodic reaction mechanism. Microscale pH measurements further confirmed these results.
New Organic Donor–Acceptor–π–Acceptor Sensitizers for Efficient Dye‐Sensitized Solar Cells and Photocatalytic Hydrogen Evolution under Visible‐Light Irradiation
Authors: Li Xing , Cui Shicong , Wang Dan , Zhou Ying , Zhou Hao , Hu Yue , Liu Jin‐gang , Long Yitao , Wu Wenjun , Hua Jianli , Tian He
Published: August 2014

Two organic donor–acceptor–π–acceptor (D‐A‐π‐A) sensitizers (AQ and AP), containing quinoxaline/pyrido[3,4‐b]pyrazine as the auxiliary acceptor, have been. Through fine‐tuning of the auxiliary acceptor, a higher designed and synthesized photoelectric conversion efficiency of 6.02 % for the AQ‐based dye‐sensitized solar cells under standard global AM1.5 solar conditions was achieved. Also, it was found that AQ‐Pt/TiO2 photocatalysts displayed a better rate of H2 evolution under visible‐light irradiation (420 nm<λ<780 nm) because of the stability of the oxidized states and the lower rates of electron recombination. Importantly, sensitizers AQ and AP‐Pt/TiO2 showed strong photocatalytic activity during continuous light soaking for 10 h with methanol as the sacrificial electron donor. Additionally, the processes of their intermolecular electron transfer were further investigated theoretically by using time‐dependent DFT. The calculated results indicate that the auxiliary acceptor plays the role of an electron trap and results in broad spectral responses.