bluuebunny/crossref_metadata_2025_split huggingface dataset:
A simulation of small to giant Antarctic iceberg evolution: Differential impact on climatology estimates
Authors: Rackow Thomas , Wesche Christine , Timmermann Ralph , Hellmer Hartmut H. , Juricke Stephan , Jung Thomas 
Published: March 2017

AbstractWe present a simulation of Antarctic iceberg drift and melting that includes small, medium‐sized, and giant tabular icebergs with a realistic size distribution. For the first time, an iceberg model is initialized with a set of nearly 7000 observed iceberg positions and sizes around Antarctica. The study highlights the necessity to account for larger and giant icebergs in order to obtain accurate melt climatologies. We simulate drift and lateral melt using iceberg‐draft averaged ocean currents, temperature, and salinity. A new basal melting scheme, originally applied in ice shelf melting studies, uses in situ temperature, salinity, and relative velocities at an iceberg's bottom. Climatology estimates of Antarctic iceberg melting based on simulations of small (≤2.2 km), “small‐to‐medium‐sized" (≤10 km), and small‐to‐giant icebergs (including icebergs >10 km) exhibit differential characteristics: successive inclusion of larger icebergs leads to a reduced seasonality of the iceberg meltwater flux and a shift of the mass input to the area north of 58°S, while less meltwater is released into the coastal areas. This suggests that estimates of meltwater input solely based on the simulation of small icebergs introduce a systematic meridional bias; they underestimate the northward mass transport and are, thus, closer to the rather crude treatment of iceberg melting as coastal runoff in models without an interactive iceberg model. Future ocean simulations will benefit from the improved meridional distribution of iceberg melt, especially in climate change scenarios where the impact of iceberg melt is likely to increase due to increased calving from the Antarctic ice sheet.
Interannual surface salinity on Northwest Atlantic shelf
Authors: Grodsky Semyon A. , Reul Nicolas , Chapron Bertrand , Carton James A. , Bryan Frank O. 
Published: March 2017

AbstractSea surface salinity (SSS) from the Aquarius and SMOS satellite missions displays a steady increase of ∼1 psu over the entire northwestern Atlantic shelf south of Nova Scotia during 2011–2015. Put in the context of longer ocean profile data, the results suggest that mixed layer salinity and temperature north of the Gulf Stream experience positively correlated shelf‐wide interannual oscillations (1 psu/2°C). Salty and warm events occur coincident with anomalous easterly‐southeasterly winds and Ekman transport counteracting the mean southwestward shelf currents. They are coincident with weakening of both branches of the Scotian Shelf Current (SSC), but only moderately correlate with shifts of the Gulf Stream North Wall. This suggests that salt advection by anomalous SSC acting on the mean salinity gradient is the primary driver regulating the transport of fresh/cold water from high latitudes. The advection mechanism imposes a connectedness of the larger‐scale interannual variability in this region and its tie to atmospheric oscillations. In the second part, an analysis of 15 year‐long numerical simulations is presented which show eight interannual salinity oscillations (positive and negative). Six of these are driven by horizontal advection by slow varying currents (>2 months), while two events are driven by horizontal eddy advection (<2 months). In line with observations, salt/warm model events correspond to anomalously weak SSC, correlate with southeasterly wind anomaly, and confirm that interannual horizontal salt advection drives interannual salinity. Indeed, vertical exchanges provide negative feedback, while interannual horizontal diffusion and the net surface salt flux anomalies are small.
Global observations of 2 day wave coupling to the diurnal tide in a high‐altitude forecast‐assimilation system
Authors: Lieberman R. S. , Riggin D. M. , Nguyen V. , Palo S. E. , Siskind D. E. , Mitchell N. J. , Stober G. , Wilhelm S. , Livesey N. J. 
Published: March 2017

AbstractWe examine wave components in a high‐altitude forecast‐assimilation system that arise from nonlinear interaction between the diurnal tide and the westward traveling quasi 2 day wave. The process yields a westward traveling “sum” wave with zonal wave number 4 and a period of 16 h, and an eastward traveling “difference” wave with zonal wave number 2 and a period of 2 days. While the eastward 2 day wave has been reported in satellite temperatures, the westward 16 h wave lies outside the Nyquist limits of resolution of twice daily local time satellite sampling. Hourly output from a high‐altitude forecast‐assimilation model is used to diagnose the nonlinear quadriad. A steady state primitive equation model forced by tide‐2 day wave advection is used to intepret the nonlinear wave products. The westward 16 h wave maximizes in the midlatitude winter mesosphere and behaves like an inertia‐gravity wave. The nonlinearly generated component of the eastward 2 day wave maximizes at high latitudes in the lower thermosphere, and only weakly penetrates to low latitudes. The 16 h and the eastward 2 day waves are of comparable amplitude and alias to the same apparent frequency when viewed from a satellite perspective.
Major dust storms and westward traveling waves on Mars
Authors: Wang Huiqun 
Published: March 2017

AbstractWestward traveling waves are observed during major dust storm periods in northern fall and winter. The close correlation in timing makes westward traveling wave one of the signature responses of the Martian atmosphere to major dust storms. Westward traveling waves are dominated by zonal wave number m = 1 in the middle atmosphere and are typically characterized by long wave period. They are associated with significant temperature perturbations near the edge of the north polar vortex. Their wind signals extend to the low latitudes and the southern hemisphere. Their eddy momentum and heat fluxes exhibit complex patterns on a global scale in the middle atmosphere.
Performance and crystallization kinetics of poly (L‐lactic acid) toughened by poly (D‐lactic acid)
Authors: Song Zhongbo , Zhen Weijun 
Published: March 2017

AbstractPoly(D‐lactic acid) (PDLA) was prepared from D‐lactic acid under optimized polymerization conditions of 1 wt% stannous octoate, at 170°C for 12 hr. Poly(L‐lactic acid) (PLLA) and its optical isomer, PDLA, were blended to improve the thermal and mechanical properties. Mechanical testing showed an increase in the impact strength of the PLLA/PDLA (0.3 wt%) by 27.6%. SEM showed more shear zones and fibrillation on the composite surfaces, compared withthe PLLA, suggesting high toughness and shock strength. TGA showed the enhanced thermal stability of PLLA composites. The DSC results indicated that the crystallinity of PLLA/PDLA (0.3 wt%) was increased by 54.31%, compared with pure PLLA. Non‐isothermal crystallization kinetics suggested the formation of crystal nucleus and the growth rate of PLLA/PDLA (0.3 wt%) increased gradually. Half crystallization time showed a decreasing trend, which could provide a large number of heterogeneous nucleation sites and improved the crystallization rate of PLLA.
Assessing the Informed Consent Skills of Emergency Medicine Resident Physicians
Authors: Binstadt Emily S. , Curl Nathaniel D. , Nelson Jessie G. , Johnson Gail L. , Hegarty Cullen B. , Knopp Robert K. 
Published: March 2017

AbstractBackgroundInformed consent (IC) is an essential component of shared medical decision making between patients and providers in emergency medicine (EM). The basic components required for adequate consent are well described, yet little is published investigating whether EM residents demonstrate adequate IC skills.ObjectiveThe objectives were to assess the ability of EM residents to obtain IC for an invasive emergency procedure using a novel assessment tool and to assess reliability and validity of the tool.MethodsThis was an observational study in which participants were initially blinded to the primary objectives of the study. Each participant conducted a video‐recorded history and physical examination with a standardized patient, requiring tube thoracostomy due to spontaneous pneumothorax. Two faculty EM physicians independently reviewed the videos and evaluated the participants’ IC skills. First, they gave an overall impression of whether IC was obtained; they then evaluated the participants using a 30‐point scoring tool based on the five elements of IC (decision‐making capacity, disclosure, voluntariness, understanding, and physician recommendation). Upon all participants’ case completion, we revealed the primary objectives and gave participants the option to withdraw from the study. Descriptive statistics and kappa coefficient were generated from the data collected.ResultsTwenty‐two residents completed the study. None withdrew from the study after the primary objectives were revealed. Twenty residents (91%) obtained adequate IC based on both reviewers’ overall impression. One disagreement occurred between reviewers (κ = 0.64). The mean IC score on a 30‐point scale was 18.5 ± 0.5.ConclusionsIn a simulated setting, most EM residents at this training program possess the knowledge and skills necessary to obtain IC prior to an invasive procedure. The assessment tool appears reliable and demonstrates construct validity.
Clinical characteristics and whole exome/transcriptome sequencing of coexisting chronic myeloid leukemia and myelofibrosis
Authors: Kandarpa Malathi , Wu Yi‐Mi , Robinson Dan , Burke Patrick William , Chinnaiyan Arul M. , Talpaz Moshe 
Published: March 2017

AbstractMyeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell (HSC) disorders that can be classified on the basis of genetic, clinical, phenotypic features. Genetic lesions such as JAK2 mutations and BCR‐ABL translocation are often mutually exclusive in MPN patients and lead to essential thrombocythemia, polycythemia vera, or myelofibrosis or chronic myeloid leukemia, respectively. Nevertheless, coexistence of these genetic aberrations in the same patient has been reported. Whether these aberrations occur in the same stem cell or a different cell is unclear, but an unstable genome in the HSCs seems to be the common antecedent. In an effort to characterize the underlying genetic events that might contribute to the appearance of more than one MPN in a patient, we studied neoplastic cells from patients with dual MPNs by next‐generation sequencing. We observed that most patients with two MPNs harbored mutations in genes known to contribute to clonal hematopoiesis through altered epigenetic regulation such as TET2, ASXL1/2, SRSF2, and IDH2 at varying frequencies (1%–47%). In addition, we found that some patients also harbored oncogenic mutations in N/KRAS, TP53, BRAF, EZH2, and GNAS at low frequencies, which probably represent clonal evolution. These findings support the hypothesis that hematopoietic cells from MPN patients harbor multiple genetic aberrations, some of which can contribute to clonal dominance. Acquiring mutations in JAK2/CALR/MPL or the BCR‐ABL translocation probably drive the oncogenic phenotype towards a specific MPN. Further, we propose that the acquisition of BCR‐ABL in these patients is frequently a secondary event resulting from an unstable genome.
Large Magnetoelectric Coupling Near Room Temperature in Synthetic Melanostibite Mn2FeSbO6
Authors: Dos santos‐García Antonio J. , Solana‐Madruga Elena , Ritter Clemens , Andrada‐Chacón Adrián , Sánchez‐Benítez Javier , Mompean Federico J. , Garcia‐Hernandez Mar , Sáez‐Puche Regino , Schmidt Rainer 
Published: March 2017

AbstractMultiferroic materials exhibit two or more ferroic orders and have potential applications as multifunctional materials in the electronics industry. A coupling of ferroelectricity and ferromagnetism is hereby particularly promising. We show that the synthetic melanostibite mineral Mn2FeSbO6 (R
space group) with ilmenite‐type structure exhibits cation off‐centering that results in alternating modulated displacements, thus allowing antiferroelectricity to occur. Massive magnetoelectric coupling (MEC) and magnetocapacitance effect of up to 4000 % was detected at a record high temperature of 260 K. The multiferroic behavior is based on the imbalance of cationic displacements caused by a magnetostrictive mechanism, which sets up an unprecedented example to pave the way for the development of highly effective MEC devices operational at or near room temperature.
Mutant Exon1 Huntingtin Aggregation is Regulated by T3 Phosphorylation‐Induced Structural Changes and Crosstalk between T3 Phosphorylation and Acetylation at K6
Authors: Chiki Anass , DeGuire Sean M. , Ruggeri Francesco S. , Sanfelice Domenico , Ansaloni Annalisa , Wang Zhe‐Ming , Cendrowska Urszula , Burai Ritwik , Vieweg Sophie , Pastore Annalisa , Dietler Giovanni , Lashuel Hilal A. 
Published: March 2017

AbstractHerein, we used protein semisynthesis to investigate, for the first time, the effect of lysine acetylation and phosphorylation, as well as the crosstalk between these modifications on the structure and aggregation of mutant huntingtin exon1 (Httex1). Our results demonstrate that phosphorylation at T3 stabilizes the α‐helical conformation of the N‐terminal 17 amino acids (Nt17) and significantly inhibits the aggregation of mutant Httex1. Acetylation of single lysine residues, K6, K9 or K15, had no effect on Httex1 aggregation. Interestingly, acetylation at K6, but not at K9 or K15, reversed the inhibitory effect of T3 phosphorylation. Together, our results provide novel insight into the role of Nt17 post‐translational modifications in regulating the structure and aggregation of Httex1 and suggest that its aggregation and possibly its function(s) are controlled by regulatory mechanisms involving crosstalk between different PTMs.
Detection of Carbapenemase‐Producing Organisms with a Carbapenem‐Based Fluorogenic Probe
Authors: Mao Wuyu , Xia Lingying , Xie Hexin 
Published: March 2017

AbstractAntibiotic resistance has become a major challenge to public health worldwide. This crisis is further aggravated by the increasing emergence of bacterial resistance to carbapenems, typically considered as the antibiotics of last resort, which is mainly due to the production of carbapenem‐hydrolyzing carbapenemases in bacteria. Herein, the carbapenem‐based fluorogenic probe CB‐1 with an unprecedented enamine–BODIPY switch is developed for the detection of carbapenemase activity. This reagent is remarkably specific towards carbapenemases over other prevalent β‐lactamases. Furthermore, the efficient imaging of live clinically important carbapenemase‐producing organisms (CPOs) with CB‐1 demonstrates its potential for the rapid detection of antibiotic resistance and timely diagnosis of CPO infections.
Synthesis of Complex Phenols Enabled by a Rationally Designed Hydroxide Surrogate
Authors: Fier Patrick S. , Maloney Kevin M. 
Published: March 2017

AbstractThe conversion of aryl halides to phenols under mild reaction conditions is a longstanding and formidable challenge in organic chemistry. Herein, we report the rational design of a broadly applicable Pd‐catalyzed method to prepare phenols with benzaldehyde oxime as a hydroxide surrogate. These reactions occur under mildly basic conditions and enable the late‐stage hydroxylation of several functionally‐dense drug‐like aryl halides.
Synthesis of Poly(arylene vinylene)s with Different End Groups by Combining Acyclic Diene Metathesis Polymerization with Wittig‐type Couplings
Authors: Miyashita Tomonari , Kunisawa Mikiko , Sueki Shunsuke , Nomura Kotohiro 
Published: March 2017

AbstractA series of end‐functionalized poly(9,9′‐di‐n‐octylfluorene vinylene)s (EF‐PFVs) with different end groups were obtained by 1) synthesizing EF‐PFV with vinyl end groups by acyclic diene metathesis (ADMET) polymerization with a molybdenum catalyst and termination with an aldehyde and 2) subsequent olefin metathesis of the vinyl group with the molybdenum catalyst followed by Wittig‐type coupling with another aldehyde. The exclusive formation of EF‐PFVs containing a vinyl end group by the ADMET polymerization was confirmed by grafting PEG, and by the synthesis of amphiphilic triblock copolymers by combining atom transfer radical polymerization from the PFV chain end with PEG grafting through a click reaction. Various EF‐PFVs with different end groups, such as C6F5, pyridyl, ferrocenyl, and terthiophene, have thus been prepared. Their fluorescence spectra (e.g., intensities, emission wavelengths) were influenced by the end groups and the length of the conjugation.
Chiral Amino Alcohol Accelerated and Stereocontrolled Allylboration of Iminoisatins: Highly Efficient Construction of Adjacent Quaternary Stereogenic Centers
Authors: Tan Qiuyuan , Wang Xinqiao , Xiong Yang , Zhao Zimeng , Li Lu , Tang Pei , Zhang Min 
Published: March 2017

AbstractWe have developed a highly efficient asymmetric allylboration of ketimines with nonchiral γ,γ‐disubstituted allylboronic acids by using a chiral amino alcohol as the directing group, which is otherwise challenging. The amino alcohol not only serves as a cheap source of nitrogen and chirality, but also dramatically enhances the reactivity. The versatility of this method was demonstrated by its ability to access all four stereoisomers with adjacent quaternary carbon centers. A reaction model was proposed to explain the diastereoselectivity and the rate‐accelerating effect.
Synthesis and Properties of Aza‐ullazines
Authors: Boldt Sebastian , Parpart Silvio , Villinger Alexander , Ehlers Peter , Langer Peter 
Published: March 2017

AbstractA range of aza‐ullazines, which represent a new heterocyclic core structure, were synthesized through a scalable four‐step reaction, including a Sonogashira reaction and metal‐free cyclization promoted by p‐toluenesulfonic acid. The optical and electrochemical properties of selected derivatives were investigated, they were found to have similar absorption and emission spectra but a higher oxidation potential than the parent ullazine core.
Different Structural Origins of the Enantioselectivity of Haloalkane Dehalogenases toward Linear β‐Haloalkanes: Open–Solvated versus Occluded–Desolvated Active Sites
Authors: Liskova Veronika , Stepankova Veronika , Bednar David , Brezovsky Jan , Prokop Zbynek , Chaloupkova Radka , Damborsky Jiri 
Published: March 2017

AbstractThe enzymatic enantiodiscrimination of linear β‐haloalkanes is difficult because the simple structures of the substrates prevent directional interactions. Herein we describe two distinct molecular mechanisms for the enantiodiscrimination of the β‐haloalkane 2‐bromopentane by haloalkane dehalogenases. Highly enantioselective DbjA has an open, solvent‐accessible active site, whereas the engineered enzyme DhaA31 has an occluded and less solvated cavity but shows similar enantioselectivity. The enantioselectivity of DhaA31 arises from steric hindrance imposed by two specific substitutions rather than hydration as in DbjA.
Oleanane‐type Saponins from Glochidion hirsutum and Their Cytotoxic Activities
Authors: Thang Nguyen Van , Thu Vu Kim , Nhiem Nguyen Xuan , Dung Duong Thi , Quang Tran Hong , Tai Bui Huu , Anh Hoang Le Tuan , Yen Pham Hai , Ngan Nguyen Thi Thanh , Hoang Nguyen Huy , Kiem Phan Van 
Published: March 2017

Five new oleanane‐type saponins, hirsutosides A – E, were isolated from the leaves of Glochidion hirsutum (Roxb.) Voigt. Their structures were elucidated as 21β‐benzoyloxy‐3β,16β,23,28‐tetrahydroxyolean‐12‐ene 3‐O‐β‐d‐glucopyranoside (1), 21β‐benzoyloxy‐3β,16β,23,28‐tetrahydroxyolean‐12‐ene 3‐O‐β‐d‐glucopyranosyl‐(1 → 3)‐β‐d‐glucopyranoside (2), 21β‐benzoyloxy‐3β,16β,23,28‐tetrahydroxyolean‐12‐ene 3‐O‐6‐acetyl‐[β‐d‐glucopyranosyl‐(1 → 3)]‐β‐d‐glucopyranoside (3), 21β‐benzoyloxy‐3β,16β,23,28‐tetrahydroxyolean‐12‐ene 3‐O‐β‐d‐glucopyranosyl‐(1 → 3)‐〈‐l‐arabinopyranoside (4), and 21β‐benzoyloxy‐3β,16β,23‐trihydroxyolean‐12‐ene‐28‐al 3‐O‐β‐d‐glucopyranosyl‐(1 → 3)‐α‐l‐arabinopyranoside (5). All isolated compounds were evaluated for cytotoxic activities on four human cancer cell lines, HepG‐2, A‐549, MCF‐7, and SW‐626 using the SRB assay. Compounds 1, 2, 4, and 5 showed significant cytotoxic activities against all human cancer cell lines with IC50 values ranging from 3.4 to 10.2 μm. Compound 3 containing acetyl group at glc C(6″) exhibited weak cytotoxic activity with IC50 values ranging from 47.0 to 54.4 μm.
Fluorescent Sensing of a Nerve Agent Simulant with Dual Emission over Wide pH Range in Aqueous Solution
Authors: Kim Youngsam , Jang Yoon Jeong , Mulay Sandip V. , Nguyen Thuy‐Tien T. , Churchill David G. 
Published: March 2017

AbstractA new 1,8‐naphthalimide‐based fluorescent probe for the detection of diethyl cyanophosphonate, a very common nerve agent simulant, is designed, synthesized, and characterized fully. The probe shows around 50‐fold enhancement of fluorescence intensity over other nerve agent simulants. Importantly, the probe is able to work under aqueous conditions in a wide pH range. Two reactive groups, the oxime and the phenol, allow a dual emission with different kinetic reactions. The reaction of diethyl cyanophosphonate with the oxime group occurs in advance; the resulting time response of the fluorescence enhancement is observed within approximately 30 s. After the oxime reaction, then phenol also undergoes a substitution reaction with diethyl cyanophosphonate, resulting in a blue emission. The real application of this new probe is demonstrated through the use of silica plate assays for the detection of diethyl cyanophosphonate in both gas and liquid phases through dual emission channels.
Direct Asymmetric Aza‐Vinylogous‐Type Michael Additions of Nitrones from Isatins to Nitroalkenes
Authors: Zhan Gu , Shi Ming‐Lin , Lin Wei‐Jia , Ouyang Qin , Du Wei , Chen Ying‐Chun 
Published: March 2017

AbstractNitrones commonly act as 1,3‐dipoles and electrophiles to furnish valuable isoxazolidine and N‐hydroxyl products, respectively. They also can be converted to nitrone ylide species and undergo [3+2] formal cycloadditions to access N‐hydroxyl pyrrolidines. Here, asymmetric direct aza‐vinylogous‐type additions of nitrones from isatins to nitroalkenes are presented, catalyzed by a bifunctional thiourea‐tertiary amine, affording highly functionalized nitrones with extended carbon skeletons in excellent stereoselectivity. Notably, the nitrone moiety can be easily removed, thus furnishing the formal asymmetric α‐functionalization of alkylamine‐type substances. Moreover, the remaining electrophilic nitrone motif enables the subsequent annulations to construct spirocyclic products in high molecular complexity and diversity, which might have potential applications for drug discovery.