bluuebunny/crossref_metadata_2025 huggingface dataset:
Tree ring records capture long‐term memory in climate systems
Authors: Schultz Colin
Published: July 2013

Measuring tree rings is a mainstay technique for estimating ancient climatic conditions, with a tree's year‐by‐year growth reflecting changes in precipitation and temperature. In some cases, paleoclimatological records compiled from tree ring measurements can stretch for thousands of years. Based on recent research, climatologists have found that hydrological and other systems have long‐term memory. Drawing on tree ring measurements compiled from across the continental United States, Bowers et al. sought to determine whether such long‐term relationships are preserved in ring width measurements. The authors analyzed the Hurst parameter—a measure of long‐term memory—of 697 different tree ring records that were collected from 10 tree species from locations across the United States. They found that though each tree species had a different mean value for its Hurst parameter, meaning that each species recorded long‐term trends in the climate differently, they all fell within the range suggestive of their being able to properly represent long‐term memory.
Storminess helps coastal marshes withstand sea level rise
Authors: Balcerak Ernie
Published: July 2013

Rising sea levels are predicted to threaten many coastal sea marshes around the world in the coming decades as the Earth's climate warms. In addition to accelerating sea level rise, global climate change is predicted to increase the frequency and severity of storms in many places around the world. However, few studies have taken into account how an increased storminess might affect the ability of coastal marshes to withstand sea level rise.
Interplanetary Space Weather: A New Paradigm
Authors: Guhathakurta Madhulika
Published: July 2013

In September 1859, Earth was hit by a solar storm so powerful that it set telegraph offices on fire and sparked northern lights in the South Pacific. Historians call it the “Carrington Event,” after English astronomer Richard Carrington, who witnessed the instigating solar flare on a projecting screen with his unaided eyes. Many consider this to be the birth of space weather.
Proposed U.S. Geological Survey Budget Would Provide “Significant” Increase
Authors: Showstack Randy
Published: July 2013

The White House's proposed budget for the U.S. Geological Survey (USGS) for fiscal year (FY) 2014, which the administration submitted to Congress on 10 April, would provide the agency with $1.17 billion, an increase of $98.02 million, 9.17% more than the FY 2012 enacted budget of $1.07 billion (see Table 1). The proposed budget is a “significant” increase and “makes a statement about the USGS's relevance in the federal research community,” USGS acting director Suzette Kimball said at the agency's briefing. Because Congress approved the FY 2013 budget just a few weeks prior to the release of the Obama administration's proposal, the FY 2014 budget is compared with the FY 2012 enacted budget here.
Research Funding Cut in Proposed Environmental Protection Agency Budget
Authors: Balcerak Ernie
Published: July 2013

The Obama administration's proposed budget for fiscal year (FY) 2014 provides a total of $8.153 billion to the Environmental Protection Agency (EPA), a decrease of $296 million from FY 2012 spending (comparisons are to FY 2012 because final appropriations for 2013 were not available when the president released his proposed FY 2014 budget).
Volcanic and Igneous Plumbing Systems: State‐of‐the‐Art and Future Developments
Authors: Galland Olivier , Burchardt Steffi , Troll Valentin
Published: July 2013

The dynamics of volcanic and igneous plumbing systems (VIPS) are governed by complex interacting chemical and mechanical processes, which control how magmas stall or propagate through the Earth's crust, the way they are emplaced, and the dynamics of their eruption. In addition, these processes control dramatic volcanotectonic phenomena such as caldera and sector collapse. Traditionally, the study of the dynamics of VIPS is method based, and relatively limited bridges between the distinct methodological approaches exist. Consequently, studies that employ different methods often lead to contradictory conclusions, illustrating a need for integrated multidisciplinary research approaches.
Canadian Arctic glacier melt is accelerating and irreversible
Authors: Schultz Colin
Published: July 2013

Ongoing glacier loss in the Canadian high Arctic is accelerating and probably irreversible, new model projections by Lenaerts et al. suggest. The Canadian high Arctic is home to the largest clustering of glacier ice outside of Greenland and Antarctica—146,000 square kilometers of glacier ice spread across 36,000 islands. In the past few years, the mass of the glaciers in the Canadian Arctic archipelago has begun to plummet. Observations from NASA's Gravity Recovery and Climate Experiment (GRACE) satellites suggest that from 2004 to 2011 the region's glaciers shed approximately 580 gigatons of ice. Aside from glacier calving, which plays only a small role in Canadian glacier mass loss, the drop is due largely to a shift in the surface mass balance, with warming‐induced meltwater runoff outpacing the accumulation of new snowfall.
Exploring the Causes of Mass Extinction Events
Authors: Keller Gerta , Kerr Andrew C. , MacLeod Norman
Published: July 2013

The Natural History Museum in London recently hosted an international, multidisciplinary conference that brought together 150 researchers in geology, geophysics, geochemistry, volcanology, sedimentology, paleontology, and astronomy to review and assess recent research into the causes of mass extinction events. Participants included experts as well as younger researchers and students. Through listening and learning from one another and by spirited constructive discussions, a new collaborative and multidisciplinary approach to resolving outstanding problems in this field was explored. The data and concepts presented and discussed at the meeting also have value well beyond the geosciences, particularly with regard to understanding modern environmental crises.
Calling All Department Heads and Chairs
Authors: Asher Pranoti M.
Published: July 2013

The AGU Heads and Chairs Workshop, offered at the Fall Meeting each year, provides an opportunity for experienced and new heads and chairs of Earth and space science departments to meet one another, discuss successful strategies and challenges, and get tips on how to build stronger departments. This year's 1‐day workshop will be held on Sunday, 8 December 2013.
Navigating Declining Budgets, Political Hurdles: A New Vision for the Future of Geoscience
Authors: Gagosian Robert B.
Published: July 2013

The Oklahoma tornadoes, Superstorm Sandy, the Tohoku tsunami, and the Deepwater Horizon oil spill are just a few examples of oceanic, atmospheric, and other Earth system disasters in the past 3 years that together claimed thousands of lives and caused hundreds of billions of dollars of damage. Basic and applied research in the geosciences were essential in supporting early warnings and forecasts that were used not only to protect lives when these natural disasters struck but also to assess risks and help society to be better able to adapt and recover after disaster struck.
Economic Growth in the Face of Weather and Climate Extremes: A Call for Better Data
Authors: Pendleton Linwood , Karl Thomas R. , Mills Evan
Published: July 2013

The U.S. economy has grown to be the world's largest, even in the face of the most varied and costly weather and climate extremes on the planet (see http://www.munichreamerica.com/webinars/2013_01_natcatreview/MunichRe_III_NatCat01032013.pdf). Nevertheless, these extremes continue to take a toll on the nation, diverting public and private funds while limiting economic growth and jobs and threatening the well‐being of Americans. Extreme weather events affect every state and manifest differently by region (see Figure 1 in Supporting Information in the online version of this Forum and http://www.ncdc.noaa.gov/billions/summary‐stats).
Obama Presents Far‐Reaching Climate Plan, Addresses Keystone Pipeline Proposal
Authors: Showstack Randy
Published: July 2013

Stating that climate change “is a challenge that does not pause for partisan gridlock,” U.S. President Barack Obama took matters into his own hands and presented a broad‐based climate action plan on 25 June. The plan, which relies on existing administrative authority and does not require congressional approval, includes three primary objectives: cutting carbon pollution in the United States, preparing the nation for the impacts of climate change, and leading international efforts to address climate change.
Dramatic Enhancement of Photoluminescence Quantum Yields for Surface‐Engineered Si Nanocrystals within the Solar Spectrum
Authors: Svrcek Vladimir , Dohnalova Katerina , Mariotti Davide , Trinh Minh Tuan , Limpens Rens , Mitra Somak , Gregorkiewicz Tom , Matsubara Koiji , Kondo Michio
Published: July 2013

Substantial improvements of the absolute photoluminescence quantum yield (QY) for surfactant‐free silicon nanocrystals (Si‐ncs) by atmospheric pressure microplasma 3‐dimensional surface engineering are reported. The effect of surface characteristics on carrier multiplication mechanisms is explored using transient induced absorption and photoluminescence QY. Surface engineering of Si‐ncs is demonstrated to lead to more than 120 times increase in the absolute QY (from 0.1% up to 12%) within an important spectral range of the solar emission (2.3–3 eV). The Si‐ncs QY is shown to be stable when Si‐ncs are stored in ethanol at ambient conditions for three months.
Brief communication: Adrenal androgens and aging: Female chimpanzees (Pan troglodytes) compared with women
Authors: Blevins James K. , Coxworth James E. , Herndon James G. , Hawkes Kristen
Published: July 2013

Ovarian cycling continues to similar ages in women and chimpanzees yet our nearest living cousins become decrepit during their fertile years and rarely outlive them. Given the importance of estrogen in maintaining physiological systems aside from fertility, similar ovarian aging in humans and chimpanzees combined with somatic aging differences indicates an important role for nonovarian estrogen. Consistent with this framework, researchers have nominated the adrenal androgen dehydroepiandrosterone (DHEA) and its sulfate (DHEAS), which can be peripherally converted to estrogen, as a biomarker of aging in humans and other primates. Faster decline in production of this steroid with age in chimpanzees could help explain somatic aging differences. Here, we report circulating levels of DHEAS in captive female chimpanzees and compare them with published levels in women. Instead of faster, the decline is slower in chimpanzees, but from a much lower peak. Levels reported for other great apes are lower still. These results point away from slowed decline but toward increased DHEAS production as one of the mechanisms underlying the evolution of human longevity. Am J Phys Anthropol 151:643–648, 2013. © 2013 Wiley Periodicals, Inc.
Hydrolyzable‐emulsifier‐containing polymer latices as dispersants and binders for waterborne carbon black paint
Authors: Itoh Yoshihiro , Ozaki Kaori , Maezawa Ryosuke
Published: July 2013

Poly(styrene‐co‐butyl methacrylate) and poly(styrene‐co‐butyl acrylate) latices were prepared by emulsion polymerization with alkali‐hydrolyzable and nonhydrolyzable cationic emulsifiers and were used as a dispersant and binder for waterborne carbon black (CB) paint. CB was dispersed in the latex solutions and then coated on filter paper pretreated with dilute aqueous Na2CO3 under mild conditions. The styrene (St)‐rich rigid copolymer latices easily dispersed the CB but fixed a little amount of the pigment on the paper surface. In contrast, the methacrylate‐ and acrylate‐rich soft latices tended to increase the adhesibility on it. We also demonstrated that the hydrolyzable‐emulsifier‐containing latices always had a higher adhesibility than the nonhydrolyzable‐emulsifier‐containing ones. Thus, the hydrolyzable‐emulsifier‐containing latices with an appropriate St content had the highest paintability, rapid adhesion, quick drying, reduced fading, superior fastness, and so on. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3869–3873, 2013
Effect of the carbonyl content on the properties of composite films based on oxidized starch and gelatin
Authors: Wang Yajuan , Jiang Lan , Duan Jingkuan , Shao Shuangxi
Published: July 2013

To improve the properties of gelatin, oxidized starch (OS) with different carbonyl content was introduced into the gelatin. In this study, we researched the influence of the carbonyl content of OS on the rheological characteristics, swelling behavior, thermal properties, and wettability of the modified gelatin film (MGF). The MGF samples were prepared by the casting of a 10% w/w solution of gelatin and OS with 18.9, 38.7, and 49.3% carbonyl content, respectively. The results of the dynamic viscosity demonstrated that the influence of the temperature on the rheological characteristics of native gelatin film (NGF) was more obvious than that of MGF. Meanwhile, the viscosity of the samples decreased with increasing carbonyl content in OS. Both the differential scanning calorimetry and thermogravimetry curves indicated that the denaturation and pyrogenic decomposition temperatures of the MGF samples were higher than those of NGF; this meant that the crosslinking between NGF and OS improved the physicochemical properties of gelatin. Compared with the NGF sample, MGF was less hydrophilic because the hydrophilic groups of gelatin could be shielded by OS. Meanwhile, the acid–base and salt sensitivity of the MGF samples were very obvious; therefore, the MGF samples could potentially be used as biomedical materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3809–3815, 2013
Modification of disposable screen‐printed carbon electrode surfaces with conductive electrospun nanofibers for biosensor applications
Authors: Ekabutr Pongpol , Chailapakul Orawan , Supaphol Pitt
Published: July 2013

In this work, we describe an alternative approach to the surface modification of screen‐printed carbon electrodes (SPCEs) to fabricate a polypyrrole/polyacrylonitrile multiwall carbon nanotube‐modified screen‐printed carbon electrode (PPy/PAN‐MWCNT/SPCE) using a two‐step process. First, PAN loaded with 5 wt % of MWCNTs was electrospun onto a carbon layer. The CNT‐embedded PAN electrospun nanofibers (average diameter ≈ 200 nm) were subsequently coated with a PPy layer via vapor‐phase polymerization using p‐toluenesulfonate as an oxidizing agent in a vacuum system. The electrochemical behavior of both the unmodified and the modified SPCEs were compared using cyclic voltammetry (CV) with common electroactive analytes in order to optimize the electrospinning and the vapor‐phase parameters. By incorporating glucose oxidase(GOX) as an enzymatic model into the modified electrode without a mediator, we conducted a calibration study which showed that glucose could be detected by an amperometer over a linear range of 0.25–6 mM with a LOD of 15.51 μM and a sensitivity of 5.41 μA/mM cm2. With a mediator, the glucose detection can be performed at low potential over a linear range of 0.125–7 mM with a LOD of 0.98 mM and a sensitivity of 14.62 μA/mM cm2. Therefore, the novel modified electrode is a promising new device for biosensor applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3885–3893, 2013
ANN modeling in Pb(II) removal from water by clay‐polymer composites fabricated via the melt‐blending
Authors: Dlamini Derrick S. , Mishra Ajay K. , Mamba Bhekie B.
Published: July 2013

This work presents two new related aspects in heavy‐metal adsorption. The first aspect is the use of Cloisite® C20A‐polycaprolactone (C20A‐PCL) composite with the aid of dry Na2SO4 in Pb(II) extraction from water. The composite was fabricated by means of the melt‐blending method at a filler loading rate of 3% (w/w). This material was able to remove 87% of Pb(II) from water despite the fact that the polymer is a thermoplastic and the C20A is hydrophobic. The second aspect is the modeling of the adsorption data obtained using polymer‐clay composites synthesized via the melt‐blending method by artificial neural networks. A network with 10 neurons and using TRAINLM, and employing tansig function in the input layer and purelin in the output layer was found to be optimal. The network was used to predict the adsorption efficiency of Pb(II) by several clay‐polymer composites and the correlation was satisfactory. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3894–3901, 2013
Highly filled graphite polybenzoxazine composites for an application as bipolar plates in fuel cells
Authors: Dueramae Isala , Pengdam Anucha , Rimdusit Sarawut
Published: July 2013

Highly filled graphite polybenzoxazine composites as bipolar plate material for polymer electrolyte membrane fuel cell (PEMFC) are developed. At the maximum graphite content of 80 wt % (68 vol %), storage modulus was increased from 5.9 GPa of the neat polybenzoxazine matrix to 23 GPa in the composite. Glass transition temperatures (Tg) of the composites were ranging from 176°C to 195°C and the values substantially increased with increasing the graphite contents. Thermal conductivity as high as 10.2 W/mK and electrical conductivity of 245 S cm−1 were obtained in the graphite filled polybenzoxazine at its maximum graphite loading. The obtained properties of the graphite filled polybenzoxazine composites exhibit most values exceed the United States department of energy requirements for PEMFC applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3909–3918, 2013
Curcumin improves the therapeutic efficacy of Listeriaat‐Mage‐b vaccine in correlation with improved T‐cell responses in blood of a triple‐negative breast cancer model 4T1
Authors: Singh Manisha , Ramos Ilyssa , Asafu‐Adjei Denise , Quispe‐Tintaya Wilber , Chandra Dinesh , Jahangir Arthee , Zang Xingxing , Aggarwal Bharat B. , Gravekamp Claudia
Published: July 2013

Success of cancer vaccination is strongly hampered by immune suppression in the tumor microenvironment (TME). Interleukin (IL)‐6 is particularly and highly produced by triple‐negative breast cancer (TNBC) cells, and has been considered as an important contributor to immune suppression in the TME. Therefore, we hypothesized that IL‐6 reduction may improve efficacy of vaccination against TNBC cancer through improved T‐cell responses. To prove this hypothesis, we investigated the effect of curcumin, an inhibitor of IL‐6 production, on vaccination of a highly attenuated Listeria monocytogenes (Listeriaat), encoding tumor‐associated antigens (TAA) Mage‐b in a TNBC model 4T1. Two therapeutic vaccination strategies with Listeriaat‐Mage‐b and curcumin were tested. The first immunization strategy involved all Listeriaat‐Mage‐b vaccinations and curcumin after tumor development. As curcumin has been consumed all over the world, the second immunization strategy involved curcumin before and all therapeutic vaccinations with Listeriaat‐Mage‐b after tumor development. Here, we demonstrate that curcumin significantly improves therapeutic efficacy of Listeriaat‐Mage‐b with both immunization strategies particularly against metastases in a TNBC model (4T1). The combination therapy was slightly but significantly more effective against the metastases when curcumin was administered before compared to after tumor development. With curcumin before tumor development in the combination therapy, the production of IL‐6 was significantly decreased and IL‐12 increased by myeloid‐derived suppressor cells (MDSC), in correlation with improved CD4 and CD8 T‐cell responses in blood. Our study suggests that curcumin improves the efficacy of Listeriaat‐Mage‐b vaccine against metastases in TNBC model 4T1 through reversal of tumor‐induced immune suppression.
Social Networking Sites: Mediating the Self and its Communities
Authors: Whittaker Lisa , Gillespie Alex
Published: July 2013

What do social networking sites reveal about the relation between the self and the community? We conceptualise social networking sites as technologies of the self and the community enabling individuals to self‐present and also objectifying the community's evaluation of individuals (through ‘structures of recognition’ such as page views, friends and lovehearts). We analyse the way in which 37 Scottish adolescents used the social networking site Bebo in nonprescribed and creative ways. First, they challenged the single authorship of profiles by co‐creating multi‐authored profiles. Second, they used creative language to obscure meaning from the preying eyes of parents, teachers and potential employers. We conclude by discussing the simplistic assumptions that Bebo makes about the relation between the self and the community. In contrast, newer social networking sites such as Facebook and Google+ are increasingly enabling people to present different facets of themselves to different communities. How people use social networking sites, and how these sites are developing to attract more users, reveals how the multiplicity of human identity is related to the multiple communities that people participate in. Copyright © 2013 John Wiley & Sons, Ltd.
Formation Kinetics and Structural Features of Beta‐Amyloid Aggregates by Sedimented Solute NMR
Authors: Bertini Ivano , Gallo Gianluca , Korsak Magdalena , Luchinat Claudio , Mao Jiafei , Ravera Enrico
Published: July 2013

The accumulation of soluble toxic beta‐amyloid (Aβ) aggregates is an attractive hypothesis for the role of this peptide in the pathology of Alzheimer's disease. We have introduced sedimentation through ultracentrifugation, either by magic angle spinning (in situ) or preparative ultracentrifuge (ex situ), to immobilize biomolecules and make them amenable for solid‐state NMR studies (SedNMR). In situ SedNMR is used here to address the kinetics of formation of soluble Aβ assemblies by monitoring the disappearance of the monomer and the appearance of the oligomers simultaneously. Ex situ SedNMR allows us to select different oligomeric species and to reveal atomic‐level structural features of soluble Aβ assemblies.
Microstructure of Bimetallic PtPd Catalysts under Oxidizing Conditions
Authors: Johns Tyne R. , Gaudet Jason R. , Peterson Eric J. , Miller Jeffrey T. , Stach Eric A. , Kim Chang H. , Balogh Michael P. , Datye Abhaya K.
Published: July 2013

Diesel oxidation catalysts (DOCs), which decrease the amount of harmful carbon monoxide (CO), nitrogen oxide (NO), and hydrocarbon (HC) emissions in engine exhaust, typically utilize Pt and Pd in the active phase. There is universal agreement that the addition of Pd improves both the catalytic performance and the durability of Pt catalysts. However, the mechanisms by which Pd improves the performance of Pt are less clear. Because these catalysts operate under oxidizing conditions, it is important to understand these catalysts in their working state. Herein, we report the microstructure of PtPd catalysts that are aged in air at 750 °C. After 10 h of aging, EXAFS and XANES analysis show that the Pt is fully reduced but that almost 30 % of the Pd species are present as an oxide. HRTEM images show no evidence of surface oxides on the metallic PtPd particles. Instead, the PdO is present as a separate phase that is dispersed over the alumina support. Within the metallic particles, Pt and Pd are uniformly distributed and there is no evidence of core–shell structures. Therefore, the improved catalytic performance is likely associated with the co‐existence of metallic Pt and Pd on the catalyst surface.
Photoswitchable Hydrogel Surface Topographies by Polymerisation‐Induced Diffusion
Authors: Stumpel Jelle E. , Liu Danqing , Broer Dirk J. , Schenning Albertus P. H. J.
Published: July 2013

Herein, we describe the preparation of patterned photoresponsive hydrogels by using a facile method. This polymer‐network hydrogel coating consists of N‐isopropylacrylamide (NIPAAM), cross‐linking agent tripropylene glycol diacrylate (TPGDA), and a new photochromic spiropyran monoacrylate. In a pre‐study, a linear NIPAAM copolymer (without TPGDA) that contained the spiropyran dye was synthesised, which showed relatively fast photoswitching behaviour. Subsequently, the photopolymerisation of a similar monomer mixture that included TPGDA afforded freestanding hydrogel polymer networks. The light‐induced isomerisation of protonated merocyanine into neutral spiropyran under slightly acidic conditions resulted in macroscopic changes in the hydrophilicity of the entire polymer film, that is, shrinkage of the hydrogel. The degree of shrinkage could be controlled by changing the chemical composition of the acrylate mixture. After these pre‐studies, a hydrogel film with spatially modulated cross‐link density was fabricated through polymerisation‐induced diffusion, by using a patterned photomask. The resulting smooth patterned hydrogel coating swelled in slightly acidic media and the swelling was higher in the regions with lower cross‐linking densities, thus yielding a corrugated surface. Upon exposure to visible light, the surface topography flattened again, thus showing that a hydrogel coating could be created, the topography of which could be controlled by light irradiation.
Molecular‐Level Insights into the Oxidative Degradation of Grafted Amines
Authors: Ahmadalinezhad Asieh , Tailor Ritesh , Sayari Abdelhamid
Published: July 2013

The oxidative degradation of CO2 adsorbents consisting of amine‐grafted pore‐expanded mesoporous MCM‐41 silica was investigated. The adsorbents were treated under flowing air at various temperatures, and the degree of deactivation was evaluated through the measurement of their CO2 adsorption capacity prior and subsequent to exposure to air. To decipher the chemical structure of surface species upon air‐deactivation of grafted amines, a solvent extraction procedure was developed using a deuterated basic solution. The obtained solutions were analyzed by a variety of 1D and 2D NMR spectroscopy techniques, such as 29Si, 13C, 1H, [1H,15N] HMBC, [1H,13C] HMQC, COSY and DOSY. The surface species generated by oxidative degradation of amine‐grafted silica were found to contain functional groups such as imine, amide and carboxylic groups. Several structural units were conclusively demonstrated.
The Ligand‐Based Quintuple Bond‐Shortening Concept and Some of Its Limitations
Authors: Noor Awal , Bauer Tobias , Todorova Tanya K. , Weber Birgit , Gagliardi Laura , Kempe Rhett
Published: July 2013

Herein, the ligand‐based concept of shortening quintuple bonds and some of its limitations are reported. In dichromium–diguanidinato complexes, the length of the quintuple bond can be influenced by the substituent at the central carbon atom of the used ligand. The guanidinato ligand with a 2,6‐dimethylpiperidine backbone was found to be the optimal ligand. The reduction of its chromium(II) chloride–ate complex gave a quintuply bonded bimetallic complex with a CrCr distance of 1.7056 (12) Å. Its metal–metal distance, the shortest observed in any stable compound yet, is of essentially the same length as that of the longest alkane CC bond (1.704 (4) Å). Both molecules, the alkane and the Cr complex, are of remarkable stability. Furthermore, an unsupported CrI dimer with an effective bond order (EBO) of 1.25 between the two metal atoms, indicated by CASSCF/CASPT2 calculations, was isolated as a by‐product. The formation of this by‐product indicates that with a certain bulk of the guanidinato ligand, other coordination isomers become relevant. Over‐reduction takes place, and a chromium–arene sandwich complex structurally related to the classic dibenzene chromium complex was observed, even when bulkier substituents are introduced at the central carbon atom of the used guanidinato ligand.
Mechanistic Study on the Cleavage and Reorganization of C(sp3)H and CN Bonds in Carbodiimides: Synthesis of 1,2‐Dihydrothiopyrimidines and 2,3‐Dihydropyrimidinthiones through Four‐Component Coupling
Authors: Wang Yang , Zhao Fei , Zhou Yi , Chi Yue , Wang Zitao , Zhang Wen‐Xiong , Xi Zhenfeng
Published: July 2013

This study sheds light on the cleavage and reorganization of C(sp3)H and CN bonds of carbodiimides in a three‐component reaction of terminal alkynes, sulfur, and carbodiimides by a combination of methods including 1) isolation and X‐ray analysis of six‐membered‐ring lithium species 2‐S, 2) trapping of the oxygen‐analogues (B‐O and D‐O) of both four‐membered‐ring intermediate B‐S and ring‐opening intermediate D‐S, 3) deuterium labeling studies, and 4) theoretical studies. These results show that 1) the reaction rate‐determining step is [2+2] cycloaddition, 2) the CN bond cleavage takes place before C(sp3)H bond cleavage, 3) the hydrogen attached to C6 in 2‐S originates from the carbodiimide, and 4) three types of new aza‐heterocycles, such as 1,2‐dihydrothiopyrimidines, N‐acyl 2,3‐dihydropyrimidinthiones, and 1,2‐dihydropyrimidinamino acids are constructed efficiently based on 2‐S. All results strongly support the idea that the reaction proceeds through [2+2] cycloaddition/4π electrocyclic ring‐opening/1,5‐H shift/6π electrocyclic ring‐closing as key steps. The research strategy on the synthesis, isolation, and reactivity investigation of important intermediates in metal‐mediated reactions not only helps achieve an in‐depth understanding of reaction mechanisms but also leads to the discovery of new synthetically useful reactions based on the important intermediates.
Empirical likelihood confidence regions for the evaluation of continuous‐scale diagnostic tests in the presence of verification bias
Authors: Wang Binhuan , Qin Gengsheng
Published: July 2013

In a continuous‐scale diagnostic test, when a cut‐off level is given, the performance of the test in distinguishing diseased subjects from non‐diseased subjects can be evaluated by its sensitivity and specificity. Joint inferences for sensitivity and specificity as well as cut‐off level play an important role in the assessment of the diagnostic accuracy of the test. Most current studies on this topic focus on complete data cases. However, in some studies, only a portion of subjects given their screening test results ultimately have their true disease status verified. In addition, the verification may depend on the test result and the subject's observed characteristics. Directly applying full data methods to verified subjects results in biased estimates, known as verification bias. In this paper, based on a general framework that combines empirical likelihood and general estimation equations with nuisance parameters, we propose various bias‐corrected joint empirical likelihood confidence regions for sensitivity and specificity with verification‐biased data. Thorough simulation studies are conducted to compare the finite sample performance of the proposed confidence regions in terms of coverage probabilities, and some suggestions are provided accordingly. Finally, an example is provided to illustrate the proposed methods.The Canadian Journal of Statistics41: 398–420; 2013 © 2013 Statistical Society of Canada
Response to Improvement of Arterial Stiffness in the Transition From Acute Decompensated Heart Failure to Chronic Compensated Heart Failure
Authors: Yalcinkaya Emre , Celik Murat , Yasar Salim , Bugan Baris
Published: July 2013

Kim DB et al. Clin Cardiol. 2013;36:358–362.
Adsorption of Fluoride on the Raw and Modified Cement Clay
Authors: Atasoy Ayse Dilek , Sahin Muge Ozdemir
Published: July 2013

Absctract

Adsorption of fluoride (F) on the raw and modified local cement clay was investigated by batch method. Modified clays were prepared through calcination, using the Na and Mg saturated (C‐Na, C‐Mg) clay at 500 and 850°C (C‐500, C‐850) and calcination of Mg incorporated clay at 500°C (C‐Mg‐500). The equilibration time was attained in 5 h. Adsorption of F increased with increasing adsorbent dose. Decrease of the initial F concentration resulted in an increasing amount of F adsorption. F adsorption isotherms fitted well with both Freundlich and Langmuir models. Low F adsorption was obtained on the raw, incorporated or calcined clays. However maximum F adsorption was found for C‐Mg‐500, with Kf and Q0 values of 0.27 and 1.69, respectively. This work indicated that the calcination of incorporated clay with Mg increased the F adsorption significantly, due to increased and stabilized positive sites.
Recurrent glioblastoma: Volumetric assessment and stratification of patient survival with early posttreatment magnetic resonance imaging in patients treated with bevacizumab
Authors: Huang Raymond Y. , Rahman Rifaquat , Hamdan Alhafidz , Kane Caroline , Chen Christina , Norden Andrew D. , Reardon David A. , Mukundun Srinivasan , Wen Patrick Y.
Published: July 2013

BACKGROUND

Despite a high radiographic response rate in patients with recurrent glioblastoma following bevacizumab therapy, survival benefit has been relatively modest. We assess whether tumor volume measurements based on baseline and early posttreatment MRI can stratify patients in terms of progression‐free survival (PFS) and overall survival (OS).

METHODS

Baseline (−4 +/‐ 4 days) and posttreatment (30 +/‐ 6 days) MRI exams of 91 patients with recurrent glioblastoma treated with bevacizumab were retrospectively evaluated for volume of enhancing tumor as well as volume of the T2/FLAIR hyperintensity. Overall survival (OS) and progression‐free survival (PFS) were assessed using volume parameters in a Cox regression model adjusted for significant clinical parameters.

RESULTS

In univariable analysis, residual tumor volume, percentage change in tumor volume, steroid change from baseline to posttreatment scan, and number of recurrences were associated with both OS and PFS. With dichotomization by sample median of 52% change of enhancing volume can stratify OS (52 weeks vs. 31 weeks, P = .013) and PFS (21 weeks vs. 12 weeks, P = .009). Residual enhancing volume, dichotomized by sample median of 7.8 cm3, can also stratify for OS (64 weeks vs. 28 weeks, P < .001) and PFS (21 weeks vs. 12 weeks, P = .036).

CONCLUSIONS

Volumetric percentage change and absolute early posttreatment volume of enhancing tumor can stratify survival for patients with recurrent glioblastoma receiving bevacizumab therapy. Cancer 2013;119:3479–3488.. © 2013 American Cancer Society.
The impact of gene expression analysis on evolving views of avian brain organization
Authors: Montiel Juan F. , Molnár Zoltán
Published: July 2013

Recent studies have presented data on adult and developing avian brain organization. Jarvis et al. ([2013] J Comp Neurol. 521:3614–3665) identify four pallial and two subpallial gene expression domains and demonstrate that the mesopallium and adjoining divisions of the hyperpallium (hyperpallium intercalatum and hyperpallium densocellulare), have very similar gene expression profiles to each other, distinct from those of the nidopallium, the arcopallium, and the more distant divisions of the hyperpallium (hyperpallium apicale). The study proposes an update of the current nomenclature (Jarvis et al. [2005] Nat Rev Neurosci. 6:151–159). The authors perform densitometric quantifications of the in situ expression of 50 selected genes, use correlations of distances between vectors that represent these gene expression patterns within the 23 avian brain regions of their study, and group them according to similarity in their expression profiles. The generated cluster tree further supports their argument for a new terminology. The authors hypothesize that the mesopallium and adjoining divisions of the hyperpallium have a common developmental origin, and in the accompanying paper (Chen et al. [2013] J Comp Neurol. 521:3666–3701) show that these structures/subdivisions initially form continuous gene expression domains. With subsequent development these domains fold into distinct subdivisions in the dorsal and ventral avian pallium, forming mirror images to each other. Jarvis et al. ([2013] J Comp Neurol. 521:3614–3665) also demonstrate interesting principles of the functional organization of the avian brain by showing that specific sensory stimulation or motor behavior elicits gene expression in functional units perpendicular to the axis of the gene expression reversal and compare their arrangements and cell types with mammalian cortical columns. J. Comp. Neurol. 521:3604–3613, 2013. © 2013 Wiley Periodicals, Inc.
Global view of the functional molecular organization of the avian cerebrum: Mirror images and functional columns
Authors: Jarvis Erich D. , Yu Jing , Rivas Miriam V. , Horita Haruhito , Feenders Gesa , Whitney Osceola , Jarvis Syrus C. , Jarvis Electra R. , Kubikova Lubica , Puck Ana E.P. , Siang‐Bakshi Connie , Martin Suzanne , McElroy Michael , Hara Erina , Howard Jason , Pfenning Andreas , Mouritsen Henrik , Chen Chun‐Chun , Wada Kazuhiro
Published: July 2013

Based on quantitative cluster analyses of 52 constitutively expressed or behaviorally regulated genes in 23 brain regions, we present a global view of telencephalic organization of birds. The patterns of constitutively expressed genes revealed a partial mirror image organization of three major cell populations that wrap above, around, and below the ventricle and adjacent lamina through the mesopallium. The patterns of behaviorally regulated genes revealed functional columns of activation across boundaries of these cell populations, reminiscent of columns through layers of the mammalian cortex. The avian functionally regulated columns were of two types: those above the ventricle and associated mesopallial lamina, formed by our revised dorsal mesopallium, hyperpallium, and intercalated hyperpallium; and those below the ventricle, formed by our revised ventral mesopallium, nidopallium, and intercalated nidopallium. Based on these findings and known connectivity, we propose that the avian pallium has four major cell populations similar to those in mammalian cortex and some parts of the amygdala: 1) a primary sensory input population (intercalated pallium); 2) a secondary intrapallial population (nidopallium/hyperpallium); 3) a tertiary intrapallial population (mesopallium); and 4) a quaternary output population (the arcopallium). Each population contributes portions to columns that control different sensory or motor systems. We suggest that this organization of cell groups forms by expansion of contiguous developmental cell domains that wrap around the lateral ventricle and its extension through the middle of the mesopallium. We believe that the position of the lateral ventricle and its associated mesopallium lamina has resulted in a conceptual barrier to recognizing related cell groups across its border, thereby confounding our understanding of homologies with mammals. J. Comp. Neurol. 521:3614–3665, 2013. © 2013 Wiley Periodicals, Inc.
Splicing factor TRA2B is required for neural progenitor survival
Authors: Roberts Jacqueline M. , Ennajdaoui Hanane , Edmondson Carina , Wirth Brunhilde , Sanford Jeremy R. , Chen Bin
Published: July 2013

Alternative splicing of pre‐mRNAs can rapidly regulate the expression of large groups of proteins. The RNA binding protein TRA2B (SFRS10) plays well‐established roles in developmentally regulated alternative splicing during Drosophila sexual differentiation. TRA2B is also essential for mammalian embryogenesis and is implicated in numerous human diseases. Precise regulation of alternative splicing is critical to the development and function of the central nervous system; however, the requirements for specific splicing factors in neurogenesis are poorly understood. This study focuses on the role of TRA2B in mammalian brain development. We show that, during murine cortical neurogenesis, TRA2B is expressed in both neural progenitors and cortical projection neurons. Using cortex‐specific Tra2b mutant mice, we show that TRA2B depletion results in apoptosis of the neural progenitor cells as well as disorganization of the cortical plate. Thus, TRA2B is essential for proper development of the cerebral cortex. J. Comp. Neurol. 522:372–392, 2014. © 2013 Wiley Periodicals, Inc.
Protein kinase C gamma interneurons in the rat medullary dorsal horn: Distribution and synaptic inputs to these neurons, and subcellular localization of the enzyme
Authors: Peirs Cédric , Patil Sudarshan , Bouali‐Benazzouz Rabia , Artola Alain , Landry Marc , Dallel Radhouane
Published: July 2013

The γ isoform of protein kinase C (PKCγ), which is concentrated in interneurons in the inner part of lamina II (IIi) of the dorsal horn, has been implicated in the expression of tactile allodynia. Lamina IIi PKCγ interneurons were shown to be activated by tactile inputs and to participate in local circuits through which these inputs can reach lamina I, nociceptive output neurons. That such local circuits are gated by glycinergic inhibition and that A‐ and C‐fibers low threshold mechanoreceptors (LTMRs) terminate in lamina IIi raise the general issue of synaptic inputs to lamina IIi PKCγ interneurons. Combining light and electron microscopic immunochemistry in the rat spinal trigeminal nucleus, we show that PKCγ‐immunoreactivity is mostly restricted to interneurons in lamina IIi of the medullary dorsal horn, where they constitute 1/3 of total neurons. The majority of synapses on PKCγ‐immunoreactive interneurons are asymmetric (likely excitatory). PKCγ‐immunoreactive interneurons appear to receive exclusively myelinated primary afferents in type II synaptic glomeruli. Neither large dense core vesicle terminals nor type I synaptic glomeruli, assumed to be the endings of unmyelinated nociceptive terminals, were found on these interneurons. Moreover, there is no vesicular glutamate transporter 3‐immunoreactive bouton, specific to C‐LTMRs, on PKCγ‐immunoreactive interneurons. PKCγ‐immunoreactive interneurons contain GABAAergic and glycinergic receptors. At the subcellular level, PKCγ‐immunoreactivity is mostly concentrated on plasma membranes, close to, but not within, postsynaptic densities. That only myelinated primary afferents were found to contact PKCγ‐immunoreactive interneurons suggests that myelinated, but not unmyelinated, LTMRs play a critical role in the expression of mechanical allodynia. J. Comp. Neurol. 522:393–413, 2014. © 2013 Wiley Periodicals, Inc.
Globally Hyperbolic Regularization of Grad's Moment System
Authors: Cai Zhenning , Fan Yuwei , Li Ruo
Published: July 2013

In this paper, we propose a globally hyperbolic regularization to the general Grad's moment system in multidimensional spaces. Systems with moments up to an arbitrary order are studied. The characteristic speeds of the regularized moment system can be analytically given and depend only on the macroscopic velocity and the temperature. The structure of the eigenvalues and eigenvectors of the coefficient matrix is fully clarified. The regularization together with the properties of the resulting moment systems is consistent with the simple one‐dimensional case discussed in 1. In addition, all characteristic waves are proven to be genuinely nonlinear or linearly degenerate, and the studies on the properties of rarefaction waves, contact discontinuities, and shock waves are included. © 2014 Wiley Periodicals, Inc.
Interaction of ZnII Porphyrin with TiO2 Nanoparticles: From Mechanism to Synthesis of Hybrid Nanomaterials
Authors: Spadavecchia Jolanda , Méthivier Christophe , Landoulsi Jessem , Pradier Claire‐Marie
Published: July 2013

The mechanism of interaction of Zn porphyrin (ZnPP) with TiO2 surfaces is investigated with a view to optimizing the synthesis of hybrid nanomaterials. The strategy consists of studying the adsorption of ZnPP on TiO2 flat surfaces by taking advantage of complementary surface characterization techniques. Combining a detailed X‐ray photoelectron spectroscopic analysis with AFM imaging allows ZnPP–surface and ZnPP intermolecular interactions to be discriminated. Probing the adsorption of ZnPP on TiO2 nanoparticles (NPs) reveals the dominant role of ZnPP‐mediated interactions, which are associated with the formation of ZnPP multilayers and/or with the state of aggregation of NPs. These preliminary investigations provide a guideline to synthesizing a novel ZnPP–TiO2 hybrid nanomaterial in a one‐step protocol. In this material, ZnPP molecules are presumably involved in the TiO2 lattice rather than on the NP surface. Furthermore, ZnPP molecules preserve their electronic properties within the TiO2 NPs, and this makes the ZnPP–TiO2 hybrid nanomaterial an excellent candidate for nanomedicine and related applications, such as localization of nanoparticles in cells and tissues or in photodynamic therapy.
Wnt5a evokes cortical axon outgrowth and repulsive guidance by tau mediated reorganization of dynamic microtubules
Authors: Li Li , Fothergill Thomas , Hutchins B. Ian , Dent Erik W. , Kalil Katherine
Published: July 2013

Wnt5a guides cortical axons in vivo by repulsion and in vitro evokes cortical axon outgrowth and repulsion by calcium signaling pathways. Here we examined the role of microtubule (MT) reorganization and dynamics in mediating effects of Wnt5a. Inhibiting MT dynamics with nocodazole and taxol abolished Wnt5a evoked axon outgrowth and repulsion of cultured hamster cortical neurons. EGFP‐EB3 labeled dynamic MTs visualized in live cell imaging revealed that growth cone MTs align with the nascent axon. Wnt5a increased axon outgrowth by reorganization of dynamic MTs from a splayed to a bundled array oriented in the direction of axon extension, and Wnt5a gradients induced asymmetric redistribution of dynamic MTs toward the far side of the growth cone. Wnt5a gradients also evoked calcium transients that were highest on the far side of the growth cone. Calcium signaling and the reorganization of dynamic MTs could be linked by tau, a MT associated protein that stabilizes MTs. Tau is phosphorylated at the Ser 262 MT binding site by CaMKII, and is required for Wnt5a induced axon outgrowth and repulsive turning. Phosphorylation of tau at Ser262 is known to detach tau from MTs to increase their dynamics. Using transfection with tau constructs mutated at Ser262, we found that this site is required for the growth and guidance effects of Wnt5a by mediating reorganization of dynamic MTs in cortical growth cones. Moreover, CaMKII inhibition also prevents MT reorganization required for Wnt5a induced axon outgrowth, thus linking Wnt/calcium signaling to tau mediated MT reorganization during growth cone behaviors. © 2013 The Authors. Developmental Neurobiology Published by Wiley Periodicals, Inc.
Develop Neurobiol 74: 797–817, 2014