bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling the fate of methane hydrates under global warming
Authors: Kretschmer Kerstin , Biastoch Arne , Rüpke Lars , Burwicz Ewa 
Published: March 2015

AbstractLarge amounts of methane hydrate locked up within marine sediments are vulnerable to climate change. Changes in bottom water temperatures may lead to their destabilization and the release of methane into the water column or even the atmosphere. In a multimodel approach, the possible impact of destabilizing methane hydrates onto global climate within the next century is evaluated. The focus is set on changing bottom water temperatures to infer the response of the global methane hydrate inventory to future climate change. Present and future bottom water temperatures are evaluated by the combined use of hindcast high‐resolution ocean circulation simulations and climate modeling for the next century. The changing global hydrate inventory is computed using the parameterized transfer function recently proposed by Wallmann et al. (2012). We find that the present‐day world's total marine methane hydrate inventory is estimated to be 1146 Gt of methane carbon. Within the next 100 years this global inventory may be reduced by ∼0.03% (releasing ∼473 Mt methane from the seafloor). Compared to the present‐day annual emissions of anthropogenic methane, the amount of methane released from melting hydrates by 2100 is small and will not have a major impact on the global climate. On a regional scale, ocean bottom warming over the next 100 years will result in a relatively large decrease in the methane hydrate deposits, with the Arctic and Blake Ridge region, offshore South Carolina, being most affected.
Impact of borehole depths on reconstructed estimates of ground surface temperature histories and energy storage
Authors: Beltrami Hugo , Matharoo Gurpreet S. , Smerdon Jason E. 
Published: March 2015

AbstractEstimates of ground surface temperature changes and continental energy storage from geothermal data have become well‐accepted indicators of climatic changes. These estimates are independent contributions to the ensemble of paleoclimatic reconstructions and have been used for the validation of general circulation models, and as a component of the energy budget accounting of the global climate system. Recent global and hemispheric analyses of geothermal data were based on data available in the borehole paleoclimatology database, which contains subsurface temperature profiles from a minimum depth of 200 m to about 600 m. Because of the nature of heat conduction, different depth ranges contain the record of past and persistent changes in the energy balance between the lower atmosphere and the ground for different time periods. Here we examine the dependency of estimated ground surface temperature histories and the magnitude of the subsurface heat content on the depth of borehole temperature profiles. Our results show that uncertainties in the estimates of the long‐term surface temperature are in the range of ±0.5K. We conclude that previous estimates of ground surface temperature change remain valid for the period since industrialization, but longer‐term estimates are subject to considerable uncertainties. The subsurface heat content shows a larger range of variability arising from differences in depth of the borehole temperature profiles, as well as from differences in the time of data acquisition, spanning four decades. These results indicate that estimates of subsurface heat should be carried out with caution to decrease cumulative errors in any spatial analysis.
Energy expenditure and activity among Hadza hunter‐gatherers
Authors: Pontzer Herman , Raichlen David A. , Wood Brian M. , Emery Thompson Melissa , Racette Susan B. , Mabulla Audax Z.P. , Marlowe Frank W. 
Published: March 2015

ObjectivesStudies of total energy expenditure, (TEE; kcal/day) among traditional populations have challenged current models relating habitual physical activity to daily energy requirements. Here, we examine the relationship between physical activity and TEE among traditional Hadza hunter‐gatherers living in northern Tanzania.MethodsHadza adults were studied at two camps, with minimal intervention so as to monitor energy expenditure and activity during normal daily life. We measured daily walking distance and walking speed using wearable GPS units for 41 adults. For a subset of 30 adults, we measured TEE using doubly labeled water, three indices of work load (foraging return rate, maternal status, and number of dependent children), and urinary biomarkers of metabolic activity and stress (8‐hydroxydeoxyguanosine, cortisol, and testosterone).ResultsFat‐free mass was the single strongest predictor of TEE among Hadza adults (r2 = 0.66, P < 0.001). Hadza men used greater daily walking distances and faster walking speeds compared with that of Hadza women, but neither sex nor any measure of physical activity or work load were correlated with TEE in analyses controlling for fat‐free mass. Compared with developed, industrial populations, Hadza adults had similar TEE but elevated levels of metabolic stress as measured by 8‐hydroxydeoxyguanosine.ConclusionOur results indicate that daily physical activity may not predict TEE within traditional hunter‐gatherer populations like the Hadza. Instead, adults with high levels of habitual physical activity may adapt by reducing energy allocation to other physiological activity. Am. J. Hum. Biol. 27:628–637, 2015. © 2015 Wiley Periodicals, Inc.
Digit ratio (2D:4D), aggression, and dominance in the Hadza and the Datoga of Tanzania
Authors: Butovskaya Marina , Burkova Valentina , Karelin Dmitry , Fink Bernhard 
Published: March 2015

ObjectivesDigit ratio (2D:4D)—a putative marker of prenatal androgen activity—has been shown to correlate with self‐reported physical aggression and dominance behavior, especially in male children and adolescents. This evidence is derived primarily from the study of Western samples.MethodsDigit ratios, self‐reported aggression, and dominance behavior were collected from men and women in two traditional, small‐scale societies, i.e., the Hadza and the Datoga of Tanzania.ResultsWe found significant differences in physical and verbal aggression, anger, and hostility between the two societies with the Datoga reporting higher scores on all four measures. Moreover, self‐reported dominance in the Datoga was higher than in the Hadza. The Datoga showed lower left and right hand 2D:4D ratios than the Hadza. Men reported higher physical and verbal aggression and dominance, and had lower 2D:4D ratios than women. A significant negative association between 2D:4D and dominance was found in Hadza women.ConclusionsWe discuss our findings with reference to differences in mating systems between the two small‐scale societies and previous findings of Western and other small‐scale societies. Am. J. Hum. Biol. 27:620–627, 2015. © 2015 Wiley Periodicals, Inc.
Synthesis of Polybenzoquinolines as Precursors for Nitrogen‐Doped Graphene Nanoribbons
Authors: Dibble David J. , Park Young S. , Mazaheripour Amir , Umerani Mehran J. , Ziller Joseph W. , Gorodetsky Alon A. 
Published: March 2015

AbstractGraphene nanoribbons (GNRs) represent promising materials for the next generation of nanoscale electronics. However, despite substantial progress towards the bottom‐up synthesis of chemically and structurally well‐defined all‐carbon GNRs, strategies for the preparation of their nitrogen‐doped analogs remain at a nascent stage. This scarce literature precedent is surprising given the established use of substitutional doping for tuning the properties of electronic materials. Herein, we report the synthesis of a previously unknown class of polybenzoquinoline‐based materials, which have potential as GNR precursors. Our scalable and facile approach employs few synthetic steps, inexpensive commercial starting materials, and straightforward reaction conditions. Moreover, due to the importance of quinoline derivatives for a variety of applications, the reported findings may hold implications across a diverse range of chemical and physical disciplines.
Energetic Materials with Promising Properties: Synthesis and Characterization of 4,4′‐Bis(5‐nitro‐1,2,3‐2H‐triazole) Derivatives
Authors: He Chunlin , Shreeve Jean'ne M. 
Published: March 2015

AbstractUsing a variety of functionalization strategies, derivatives of 4, 4′‐bis(5‐nitro‐1,2,3‐2H‐triazole) were designed, synthesized, and characterized. The isomers were separated, their structures were confirmed with single‐crystal X‐ray analysis, and their properties were determined by differential scanning calorimetry, density, impact sensitivity, heat of formation, and detonation velocity and pressure (calculated by EXPLO5 V6.01). Those materials were found to exhibit superior detonation performance when compared with the other fully carbon‐nitrated bis(azoles).
Eine hocheffiziente Gold‐katalysierte Photoredox‐α‐C(sp3)‐H‐ Alkinylierung von tertiären aliphatischen Aminen durch Sonnenlicht
Authors: Xie Jin , Shi Shuai , Zhang Tuo , Mehrkens Nina , Rudolph Matthias , Hashmi A. Stephen K. 
Published: March 2015

AbstractEine neue α‐C(sp3)‐H‐Alkinylierung nichtaktivierter tertiärer aliphatischer Amine mit 1‐Iodalkinen als radikalische Alkinylierungsreagentien in Gegenwart von [Au2(μ‐dppm)2]2+ im Sonnenlicht liefert Propargylamine. Basierend auf mechanistischen Studien zur C(sp3)‐C(sp)‐Bindungsknüpfung wird eine C‐C‐Kupplung eines α‐Aminoalkylradikals und eines Alkinylradikals vorgeschlagen. Die milden, einfachen, effizienten und hochselektiven C(sp3)‐H‐Alkinylierungen zeigen eine exzellente Regioselektivität und eine gute Toleranz gegenüber funktionellen Gruppen. Gramm‐Mengen konnten mit Sonnenlicht als saubere und nachhaltige Energiequelle umgesetzt werden.
Self‐Immolative Poly(4,5‐dichlorophthalaldehyde) and its Applications in Multi‐Stimuli‐Responsive Macroscopic Plastics
Authors: DiLauro Anthony M. , Lewis Gregory G. , Phillips Scott T. 
Published: March 2015

AbstractEnd‐capped poly(4,5‐dichlorophthalaldehyde) (PCl2PA), which is a new self‐immolative CDr polymer with the unique capability of depolymerizing continuously and completely in the solid state when an end cap is cleaved from the polymer by reaction with a specific molecular signal, is described. End‐capped poly(4,5‐dichlorophthalaldehyde) is sufficiently stable to enable patterning of three‐dimensional macroscopic polymeric materials by selective laser sintering. These unique materials are capable of 1) autonomously amplifying macroscopic changes in the material in response to specific molecular inputs, and 2) altering their responses depending on the identity of the applied signal. Thus, not only does end‐capped PCl2PA provide new and unique capabilities compared to the small subset of existing CDr polymers, but it also provides access to a new class of stimuli‐responsive materials.
Synthesis of Each Enantiomer of Rocaglamide by Means of a Palladium(0)‐Catalyzed Nazarov‐Type Cyclization
Authors: Zhou Zhe , Tius Marcus A. 
Published: March 2015

AbstractA recently reported Pd0‐catalyzed asymmetric Nazarov‐type cyclization has been successfully applied in the key step of the first catalytic asymmetric total synthesis of (−)‐rocaglamide (natural) and (+)‐rocaglamide. The stereochemistry at the C3 position that controls the stereochemistry of all other stereocenters is determined in the cyclization step. This versatile and modular synthesis proceeds from simple reagents.
meso‐Dibenzoporphycene has a Large Bathochromic Shift and a Porphycene Framework with an UnusualcisTautomeric Form
Authors: Oohora Koji , Ogawa Ayumu , Fukuda Tamaki , Onoda Akira , Hasegawa Jun‐ya , Hayashi Takashi 
Published: March 2015

Abstractmeso‐Monobenzoporphycene (mMBPc) andmeso‐dibenzoporphycene (mDBPc), in which one or two benzene moieties are fused at ethylene‐bridged positions (meso‐positions) of porphycene, were prepared in an effort to further delocalize the π‐electrons within the porphycene molecule. mMBPc and mDBPc were fully characterized by mass spectrometry,1H and13C NMR spectroscopy, and X‐ray crystallography. The longest‐wavelength Q‐bands of mMBPc and mDBPc are red‐shifted by 92 nm and 418 nm, respectively, compared to that of the unsubstituted porphycene (Pc). Electrochemical measurements indicate that the HOMO is destabilized and the LUMO is stabilized by the fused benzene moieties at themeso positions. Furthermore, both XPS and theoretical studies support the presence of acistautomeric form in the ground state of mDBPc, despite the fact that essentially all known porphycene derivatives adopt thetranstautomeric form.
Direct Catalytic Asymmetric Aldol Reaction of an α‐Azido Amide
Authors: Weidner Karin , Sun Zhongdong , Kumagai Naoya , Shibasaki Masakatsu 
Published: March 2015

AbstractA direct aldol reaction of an α‐azido 7‐azaindolinylamide, promoted by a Cu‐based cooperative catalyst, is documented. Aromatic aldehydes bearing an ortho substituent exhibited diastereodivergency depending on the nature of the chiral ligands used. Smooth reactions with ynals highlighted the broad substrate scope. A vicinal azido alcohol unit in the product allowed direct access to the corresponding aziridine and facile hydrolysis of the 7‐azaindolinylamide moiety furnished enantioenriched β‐hydroxy‐α‐azido carboxylic acid derivatives.
The Many Faces of FOX‐7: A Precursor to High‐Performance Energetic Materials
Authors: Gao Haixiang , Shreeve Jean'ne M. 
Published: March 2015

AbstractNew derivatives of 1,1‐diamino‐2, 2‐dinitroethene (FOX‐7) are reported. These highly oxygen‐ and nitrogen‐rich compounds were fully characterized using IR and multinuclear NMR spectroscopy, elemental analysis (EA), and differential scanning calorimetry (DSC). X‐ray structure determination of (E)‐1,2‐bis{(E)‐2‐chloro‐1‐(chloroimino)‐2,2‐dinitroethyl}diazene) (10), N1, N2‐dichloro‐1, 2‐diazenedicarboximidamide (11), and (E,E)‐N,N′‐1,2‐ethanediylidenebis(2, 2‐dinitro‐2‐chloro‐ethanamine) (12) was helpful in their characterization. Heats of formation (HOF) were calculated (Gaussian 03) and combined with experimental densities to estimate the detonation velocities (D) and pressures (P) of the high‐energy‐density materials (HEDMs) (EXPLO5, v6.01). The compounds exhibit good thermal stability, high density, positive HOF, acceptable oxygen balances, and excellent detonation properties, which often are superior to that of 1,3,5‐trinitroperhydro‐1,3,5‐triazine (RDX).
A Highly Efficient Gold‐Catalyzed Photoredox α‐C(sp3)H Alkynylation of Tertiary Aliphatic Amines with Sunlight
Authors: Xie Jin , Shi Shuai , Zhang Tuo , Mehrkens Nina , Rudolph Matthias , Hashmi A. Stephen K. 
Published: March 2015

AbstractA new α‐C(sp3)H alkynylation of unactivated tertiary aliphatic amines with 1‐iodoalkynes as radical alkynylating reagents in the presence of [Au2(μ‐dppm)2]2+ in sunlight provides propargylic amines. Based on mechanistic studies, a CC coupling of an α‐aminoalkyl radical and an alkynyl radical is proposed for the C(sp3)C(sp) bond formation. The mild, convenient, efficient, and highly selective C(sp3)H alkynylation reaction shows excellent regioselectivity and good functional‐group compatibility. A scale‐up to gram quantities is possible with sunlight used as a clean and sustainable energy source.
Accidents, Evocative Objects and Art: Meanderings of the Mind in the Work of Christopher Bollas and Gabriel Orozco
Authors: Marks Lesley 
Published: March 2015

AbstractThis study compares Christopher Bollas's theory of thinking and the creative process, both within and outside of the psychoanalytic encounter, with the work of artist and sculptor Gabriel Orozco. It demonstrates the parallels between the psychoanalytic quest for the true self and the artistic endeavor to create art that offers a potentially transformative experience. Orozco's art and Bollas's psychoanalytic theories are inter‐animating and mutually reinforcing, giving a discursive and visual form to ideas concerned with the fully‐lived life and the search for personal truth. Copyright © 2015 John Wiley & Sons, Ltd.
Analysis of factors that may be essential in the decision to fly on fully autonomous passenger airliners
Authors: Vance Samuel M. , Malik Arif S. 
Published: March 2015

SummaryThis research investigates factors that influence opinion in the decision to fly on fully autonomous passenger airliners primarily from the perspective of aviation and technology professionals. Bayesian statistical inference and a two‐level fractional factorial survey are used to sample passengers' views on fully autonomous airliners. Eight trust, safety, and cost factors are incorporated into a vignette set in the future. Factors include automation levels, safety records, liability guarantees, airline integrity, and service disruptions. Dependent variables exist in five post‐vignette questions and essentially ask “Would you” or “Would you not” be willing to fly on a fully autonomous airliner? Sixteen versions of the vignette, each with unique trust, safety, and cost levels, present varying (unknown) degrees of influence to the survey respondents. For every demographic, the research shows a 99% statistically significant difference between the “prior” and “posterior” sampled population proportions willing to fly. The most significant positive influence involves integrity characteristics of the airline, while the most negative influence relates to life insurance liability guarantees. Research from 2003 suggested that this mode of travel would be acceptable to only 10.5% of respondents. When the 2003 research is used as a Bayesian prior probability, the resulting posterior probability for the demographics sampled can be modeled as a beta distribution, indicating 95% probability that the sampled proportion of the population willing to fly is between 33.2% and 36.4%. After adjusting for age and profession demographics to match the US population, the 95% probability bounds on the proportion willing to fly are 31.35% and 34.15%. Copyright © 2015 John Wiley & Sons, Ltd.
Are Longshots Only for Losers? A New Look at the Last Race Effect
Authors: McKenzie Craig R. M. , Sher Shlomi , Müller‐Trede Johannes , Lin Charlette , Liersch Michael J. , Rawstron Anthony George 
Published: March 2015

AbstractThere is evidence that betting on longshots increases in the last race of a day of horse racing. Previous accounts have assumed that the phenomenon is driven by bettors who have lost money and are trying to recoup their losses. To test this assumption of “reference dependence,” three laboratory experiments simulated a day at the races: In each of several rounds, participants chose either (i) a gamble with a small probability of a large gain and a large probability of a small loss (the “longshot”) or (ii) a gamble with a moderate chance of a small gain or a small loss (the “favorite”). The first two experiments employed a game played for points, while a third experiment included monetary incentives and stimuli drawn from a real day of racing. These experiments provide a clear demonstration of the last race effect in a laboratory setting. However, the results indicate that the effect is largely reference independent: Participants were more likely to choose the longshot in the last round regardless of whether, and how much, they had won or lost in previous rounds. Winning or losing, bettors prefer to “go out with a bang” at the end of a series of gambles. Copyright © 2015 John Wiley & Sons, Ltd.
The fusion of Toxoplasma gondii SAG1 vaccine candidate to Leishmania infantum heat shock protein 83‐kDa improves expression levels in tobacco chloroplasts
Authors: Albarracín Romina M. , Becher Melina Laguía , Farran Inmaculada , Sander Valeria A. , Corigliano Mariana G. , Yácono María L. , Pariani Sebastián , López Edwin Sánchez , Veramendi Jon , Clemente Marina 
Published: March 2015

AbstractChloroplast transformation technology has emerged as an alternative platform offering many advantages over nuclear transformation. SAG1 is the main surface antigen of the intracellular parasite Toxoplasma gondii and a promising candidate to produce an anti‐T. gondii vaccine. The aim of this study was to investigate the expression of SAG1 using chloroplast transformation technology in tobacco plants. In order to improve expression in transplastomic plants, we also expressed the 90‐kDa heat shock protein of Leishmania infantum (LiHsp83) as a carrier for the SAG1 antigen. SAG1 protein accumulation in transplastomic plants was approximately 0.1–0.2 μg per gram of fresh weight (FW). Fusion of SAG1 to LiHsp83 significantly increased the level of SAG1 accumulation in tobacco chloroplasts (by up to 500‐fold). We also evaluated the functionality of the chLiHsp83‐SAG1. Three human seropositive samples reacted with SAG1 expressed in transplastomic chLiHsp83‐SAG1 plants. Oral immunization with chLiHsp83‐SAG1 elicited a significant reduction of the cyst burden that correlated with an increase of SAG1‐specific antibodies. We propose the fusion of foreign proteins to LiHsp83 as a novel strategy to increase the expression level of the recombinant proteins using chloroplast transformation technology, thus addressing one of the current challenges for this approach in antigen protein production.
Brevetoxin, the Dinoflagellate Neurotoxin, Localizes to Thylakoid Membranes and Interacts with the Light‐Harvesting Complex II (LHCII) of Photosystem II
Authors: Cassell Ryan T. , Chen Wei , Thomas Serge , Liu Li , Rein Kathleen S. 
Published: March 2015

AbstractThe brevetoxins are neurotoxins that are produced by the “Florida red tide” dinoflagellate Karenia brevis. They bind to and activate the voltage‐gated sodium channels in higher organisms, specifically the Nav1.4 and Nav1.5 channel subtypes. However, the native physiological function that the brevetoxins perform for K. brevis is unknown. By using fluorescent and photoactivatable derivatives, brevetoxin was shown to localize to the chloroplast of K. brevis where it binds to the light‐harvesting complex II (LHCII) and thioredoxin. The LHCII is essential to non‐photochemical quenching (NPQ), whereas thioredoxins are critical to the maintenance of redox homeostasis within the chloroplast and contribute to the scavenging of reactive oxygen. A culture of K. brevis producing low levels of toxin was shown to be deficient in NPQ and produced reactive oxygen species at twice the rate of the toxic culture, implicating a role in NPQ for the brevetoxins.