bluuebunny/crossref_metadata_2025_split huggingface dataset:
Climatic uncertainty in Himalayan water towers
Authors: Mishra Vimal 
Published: February 2015

AbstractThe Himalayan water towers (e.g., Indus, Ganges, and Brahmaputra) play a major role in water resource availability and affect a significant population in the South Asia region. Climatic uncertainty in the region not only hampers progress toward process understanding but also decision making. Observational data sets show uncertainty (standard deviation in mean temperature in data sets) of 0.2 to 0.5°C in winter (January‐February‐March‐April) and the monsoon season (June‐July‐August‐September) air temperature. Observational uncertainty in precipitation in the winter and monsoon seasons ranged between 6 and 17% (with respect to ensemble mean seasonal precipitation) in the Indus, Ganges, and Brahmaputra river basins. The Coordinated Regional Climate Downscaling Experiment (CORDEX) South Asia regional climate models (CORDEX‐RCMs) show larger uncertainty (1–3.6°C in temperature and 18–60% in precipitation) than that of the observations. Moreover, RCMs exhibit a large cold bias (6–8°C) and are not able to reproduce the observed warming in the Himalayan water towers. In fact, the CORDEX‐RCMs overestimate observed warming by threefold in Ganges and Brahmaputra basins, which raises a question on their reliability on future warming trends in the region. The CORDEX‐RCMs overestimate the area that experienced significant warming and fail to reproduce precipitation trends in both magnitude as well as direction. In observational data sets, uncertainty in precipitation and air temperature increases with elevation, which may be associated with sparse observations. However, the CORDEX‐RCMs showed larger uncertainty at the lower elevations in both precipitation as well as temperature. The host general circulation models show a better performance in simulating winter climate than the CORDEX‐RCMs, which suggest that an improved representation of elevation may not necessarily improve the model's performance. While observations show significant warming in the Indus basin and decline in the monsoon season precipitation in the Ganges basin, reliability of future climate projections and their impacts on water resources in the region will depend on improvements in the models and observations in coming years.
Observing and modeling the influence of layering on bubble trapping in polar firn
Authors: Mitchell Logan E. , Buizert Christo , Brook Edward J. , Breton Daniel J. , Fegyveresi John , Baggenstos Daniel , Orsi Anais , Severinghaus Jeffrey , Alley Richard B. , Albert Mary , Rhodes Rachael H. , McConnell Joseph R. , Sigl Michael , Maselli Olivia , Gregory Stephanie , Ahn Jinho 
Published: February 2015

AbstractInterpretation of ice core trace gas records depends on an accurate understanding of the processes that smooth the atmospheric signal in the firn. Much work has been done to understand the processes affecting air transport in the open pores of the firn, but a paucity of data from air trapped in bubbles in the firn‐ice transition region has limited the ability to constrain the effect of bubble closure processes. Here we present high‐resolution measurements of firn density, methane concentrations, nitrogen isotopes, and total air content that show layering in the firn‐ice transition region at the West Antarctic Ice Sheet (WAIS) Divide ice core site. Using the notion that bubble trapping is a stochastic process, we derive a new parameterization for closed porosity that incorporates the effects of layering in a steady state firn modeling approach. We include the process of bubble trapping into an open‐porosity firn air transport model and obtain a good fit to the firn core data. We find that layering broadens the depth range over which bubbles are trapped, widens the modeled gas age distribution of air in closed bubbles, reduces the mean gas age of air in closed bubbles, and introduces stratigraphic irregularities in the gas age scale that have a peak‐to‐peak variability of ~10 years at WAIS Divide. For a more complete understanding of gas occlusion and its impact on ice core records, we suggest that this experiment be repeated at sites climatically different from WAIS Divide, for example, on the East Antarctic plateau.
Role of water vapor and convection‐circulation decoupling in MJO simulations by a tropical channel model
Authors: Ulate Marcela , Zhang Chidong , Dudhia Jimy 
Published: February 2015

AbstractA tropical channel model failed to simulate an observed MJO event. As a means to find reasons for the failure, model errors in water vapor (qv) and other fields were corrected to different extents by nudging towards a global reanalysis product. An MJO metric was developed to quantify the realism of a simulated MJO event in the amplitude and zonal propagation speed of its precipitation and zonal wind at 850 hPa (U850). Results show that correcting errors in qv alone is necessary and sufficient for a realistic simulation of the MJO event. Correcting errors in other fields is insufficient by itself and unnecessary with water vapor correction. For a realistic MJO simulation, error corrections are needed for qv perturbations of the planetary scales (zonal wave number 1–3) together with its zonal mean in both the lower and middle troposphere. Correcting errors in qv at upper levels, planetary‐scale perturbations of any single zonal wave number, synoptic‐scale perturbations, or temporal/zonal means alone is not sufficient for a realistic MJO simulation. Amplitudes of MJO precipitation and U850 are significantly correlated, but their propagation speeds are not. MJO signals in U850 are easier than those in precipitation to improve by correcting errors in qv. In the absence of MJO intrinsic dynamics, inserted MJO signals in qv in a simulation may create a phantom MJO event in precipitation but not in the circulation. This study confirms the existing knowledge on the importance of qv to MJO simulations, sheds new lights on the role of the qv spatial structure, and presents evidence for possible precipitation‐circulation decoupling in MJO simulations.
How obliquity cycles powered early Pleistocene global ice‐volume variability
Authors: Tabor Clay R. , Poulsen Christopher J. , Pollard David 
Published: February 2015

AbstractMilankovitch theory proposes that the magnitude of high‐latitude summer insolation dictates the continental ice‐volume response by controlling summer snow melt, thus anticipating a substantial ice‐volume contribution from the strong summer insolation signal of precession. Yet almost all of the early Pleistocene δ18O records' signal strength resides at the frequency of obliquity. Here we explore this discrepancy using a climate‐vegetation‐ice sheet model to simulate climate‐ice sheet response to transient orbits of varying obliquity and precession. Spectral analysis of our results shows that despite contributing significantly less to the summer insolation signal, almost 60% of the ice‐volume power exists at the frequency of obliquity due to a combination of albedo feedbacks, seasonal offsets, and orbital cycle duration differences. Including eccentricity modulation of the precession ice‐volume component and assuming a small Antarctic ice response to orbital forcing produce a signal that agrees with the δ18O ice‐volume proxy records.
Response of Karakoram‐Himalayan glaciers to climate variability and climatic change: A regional climate model assessment
Authors: Kumar Pankaj , Kotlarski Sven , Moseley Christopher , Sieck Kevin , Frey Holger , Stoffel Markus , Jacob Daniela 
Published: February 2015

AbstractThe Karakoram and the Himalayan mountain range accommodate a large number of glaciers and are the major source of several perennial rivers downstream. To interactively describe to response of glaciers to climate change, a glacier parameterization scheme has been developed and implemented into the regional climate model REMO. The scheme simulates the mass balance as well as changes of the areal extent of glaciers on a subgrid scale. The parameterization scheme is for the first time applied to the region. A regional glacier inventory is compiled and is used to initialize glacier area and volume. Over the highly complex and data sparse region, the simulated mass balance largely agrees with observations including the positive Karakoram anomaly. The simulated equilibrium line altitude is well captured although a systematic underestimation is apparent. REMO simulates the glacier‐climate interaction reasonably well; it has clear potential to be used for future climate assessments.
A Smart DNAzyme–MnO2 Nanosystem for Efficient Gene Silencing
Authors: Fan Huanhuan , Zhao Zilong , Yan Guobei , Zhang Xiaobing , Yang Chao , Meng Hongmin , Chen Zhuo , Liu Hui , Tan Weihong 
Published: February 2015

AbstractDNAzymes hold promise for gene‐silencing therapy, but the lack of sufficient cofactors in the cell cytoplasm, poor membrane permeability, and poor biostability have limited the use of DNAzymes in therapeutics. We report a DNAzyme–MnO2 nanosystem for gene‐silencing therapy. MnO2 nanosheets adsorb chlorin e6‐labelled DNAzymes (Ce6), protect them from enzymatic digestion, and efficiently deliver them into cells. The nanosystem can also inhibit 1O2 generation by Ce6 in the circulatory system. In the presence of intracellular glutathione (GSH), MnO2 is reduced to Mn2+ ions, which serve as cofactors of 10–23 DNAzyme for gene silencing. The release of Ce6 generates 1O2 for more efficient photodynamic therapy. The Mn2+ ions also enhance magnetic resonance contrast, providing GSH‐activated magnetic resonance imaging (MRI) of tumor cells. The integration of fluorescence recovery and MRI activation provides fluorescence/MRI bimodality for monitoring the delivery of DNAzymes.
Electrolytic Macrocyclizations: Scalable Synthesis of a Diazonamide‐Based Drug Development Candidate
Authors: Ding Hui , DeRoy Patrick L. , Perreault Christian , Larivée Alexandre , Siddiqui Arshad , Caldwell Charles G. , Harran Susan , Harran Patrick G. 
Published: February 2015

AbstractAn electrochemical method to synthesize the core macrolactam of diazonamides is described. Large ring‐forming dehydrogenation is initiated by anodic oxidation at a graphite surface. The reaction requires no tailoring of the substrate and occurs at ambient temperature in aqueous DMF in an undivided cell open to air. This unique chemistry has enabled a concise, scalable preparation of DZ‐2384; a refined analog of diazonamide A slated for clinical development as a cancer therapeutic.
Active Targeting of Tumors through Conformational Epitope Imprinting
Authors: Zhang Yan , Deng Chunyue , Liu Sha , Wu Jin , Chen Zhangbao , Li Chong , Lu Weiyue 
Published: February 2015

AbstractInspired by the knowledge that most antibodies recognize a conformational epitope because of the epitope’s specific three‐dimensional shape rather than its linear structure, we combined scaffold‐based peptide design and surface molecular imprinting to fabricate a novel nanocarrier harboring stable binding sites that captures a membrane protein. In this study, a disulfide‐linked α‐helix‐containing peptide, apamin, was used to mimic the extracellular, structured N‐terminal part of the protein p32 and then serve as an imprinting template for generating a sub‐40 nm‐sized polymeric nanoparticle that potently binds to the target protein, recognizes p32‐positive tumor cells, and successfully mediates targeted photodynamic therapy in vivo. This could provide a promising alternative for currently used peptide‐modified nanocarriers and may have a broad impact on the development of polymeric nanoparticle‐based therapies for a wide range of human diseases.
Cerium(IV)‐Driven Water Oxidation Catalyzed by a Manganese(V)–Nitrido Complex
Authors: Ma Li , Wang Qian , Man Wai‐Lun , Kwong Hoi‐Ki , Ko Chi‐Chiu , Lau Tai‐Chu 
Published: February 2015

AbstractThe study of manganese complexes as water‐oxidation catalysts (WOCs) is of great interest because they can serve as models for the oxygen‐evolving complex of photosystem II. In most of the reported Mn‐based WOCs, manganese exists in the oxidation states III or IV, and the catalysts generally give low turnovers, especially with one‐electron oxidants such as CeIV. Now, a different class of Mn‐based catalysts, namely manganese(V)–nitrido complexes, were explored. The complex [MnV(N)(CN)4]2− turned out to be an active homogeneous WOC using (NH4)2[Ce(NO3)6] as the terminal oxidant, with a turnover number of higher than 180 and a maximum turnover frequency of 6 min−1. The study suggests that active WOCs may be constructed based on the MnV(N) platform.
Biomass of invasive plant species as a potential feedstock for bioenergy production
Authors: Van Meerbeek Koenraad , Appels Lise , Dewil Raf , Calmeyn Annelies , Lemmens Pieter , Muys Bart , Hermy Martin 
Published: February 2015

AbstractInvasive alien species (IAS) are one of the most important drivers of species loss. A series of recent (inter)national policies and guidelines however did not prevent new introductions and further spread of non‐indigenous species. But instead of considering invasive plant species as a burden, the biomass production of IAS can be considered and used as an ecosystem service. To assess the possibilities for bioenergy production of four invasive alien plant species in Europe, Fallopia japonica, Heracleum mantegazzianum, Impatiens glandulifera and Solidago gigantea, we determined their biomass production, gross calorific value and biogas yield. The viability of the propagules after digestion was also tested to assess the dispersal risk related to the bioenergy chain. Fallopia japonica and S. gigantea achieved a high annual biomass yield of 8.6 ton DM per hectare. Impatiens glandulifera and H. mantegazzianum had a lower biomass production (5.8 and 6.0 ton DM ha−1). Without extra inputs or agronomic optimization of the crops, the anaerobic digestion of the studied invasive plant species achieved comparable energy outputs per hectare (28–88 GJ ha−1) as some of the current bioenergy systems. All propagules lost their viability after digestion. The risk of further invasion is thus minimized during the digestion process. However, caution during harvest and transport is required to prevent the spread of new propagules. The energetic valorization of the biomass of IAS can create an economic incentive for habitat restoration of invaded sites and offers the opportunity to reconcile the restoration of the invaded habitats with renewable energy goals. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd
Activity of second‐generation ALK inhibitors against crizotinib‐resistant mutants in an NPM‐ALK model compared to EML4‐ALK
Authors: Fontana Diletta , Ceccon Monica , Gambacorti‐Passerini Carlo , Mologni Luca 
Published: February 2015

AbstractAnaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor involved in both solid and hematological tumors. About 80% of ALK‐positive anaplastic large‐cell lymphoma (ALCL) cases are characterized by the t(2;5)(p23;q35) translocation, encoding for the aberrant fusion protein nucleophosmin (NPM)‐ALK, whereas 5% of non‐small‐cell lung cancer (NSCLC) patients carry the inv(2)(p21;p23) rearrangement, encoding for the echinoderm microtubule‐associated protein‐like 4 (EML4)‐ALK fusion. The ALK/c‐MET/ROS inhibitor crizotinib successfully improved the treatment of ALK‐driven diseases. However, several cases of resistance appeared in NSCLC patients, and ALK amino acid substitutions were identified as a leading cause of resistance to crizotinib. Second‐generation ALK inhibitors have been developed in order to overcome crizotinib resistance. In this work, we profiled in vitro the activity of crizotinib, AP26113, ASP3026, alectinib, and ceritinib against six mutated forms of ALK associated with clinical resistance to crizotinib (C1156Y, L1196M, L1152R, G1202R, G1269A, and S1206Y) and provide a classification of mutants according to their level of sensitivity/resistance to the drugs. Since the biological activity of ALK mutations extends beyond the specific type of fusion, both NPM‐ALK‐ and EML4‐ALK‐positive cellular models were used. Our data revealed that most mutants may be targeted by using different inhibitors. One relevant exception is represented by the G1202R substitution, which was highly resistant to all drugs (>10‐fold increased IC50 compared to wild type) and may represent the most challenging mutation to overcome. These results provide a prediction of cross‐resistance of known crizotinib‐resistant mutations against all second‐generation tyrosine kinase inhibitors (TKIs) clinically available, and therefore could be a useful tool to help clinicians in the management of crizotinib‐resistance cases.
Synthesis of Oxazolidinones from Epoxides and Isocyanates Catalyzed by Rare‐Earth‐Metal Complexes
Authors: Wang Peng , Qin Jie , Yuan Dan , Wang Yaorong , Yao Yingming 
Published: February 2015

AbstractRare‐earth‐metal complexes stabilized by an amino‐bridged triphenolate ligand showed high efficiency in catalyzing the cycloaddition of isocyanates and epoxides in the presence of NBu4I under mild conditions. This strategy is applicable to both terminal and disubstituted epoxides as well as various isocyanates, and tolerated different types of functional groups. Moreover, it is highly regio‐ and stereoselective, and afforded 3,5‐disubstituted oxazolidinones as the only products in most cases in moderate to good yields.
Hotelling trace criterion as a figure of merit for the optimization of chromatogram alignment
Authors: Soares Edward J. , Yalla Gopal R. , O'Connor John B. , Walsh Kevin A. , Hupp Amber M. 
Published: February 2015

We present a methodology for optimization of chromatogram alignment using a class separability measure called the Hotelling trace criterion (HTC). This metric is a multi‐class distance measure that accounts for within‐class and between‐class variation. We chose the correlation optimized warping algorithm as our alignment method and used the HTC to judge the effectiveness of the alignment based on algorithm parameters called segment length and max warp.Biodiesel feedstock samples representing classes of soy, canola, tallow, waste grease, and hybrid were used in our experiments. Fatty acid methyl esters in each biodiesel were separated using gas chromatography‐mass spectroscopy. The entire data set was baseline corrected, aligned, normalized, and mean‐centered prior to principal components (PCs) analysis. The aligned, baseline corrected data sets were used to compute a figure of merit called warping effect, while the PC‐transformed data sets were used to evaluate the HTC. The segment length and max warp parameters that maximized the warping effect and/or HTC were then determined. Scores plots of pairs of PCs, along with 95% confidence ellipses, were created and analyzed.The results demonstrated that the parameters derived from maximizing the HTC more effectively aligned the data, as evidenced by better clustering of the biodiesels in the scores plots. This behavior was robust to the number of PCs used in the computation of the HTC. We conclude that the HTC is an objective measure of alignment quality that allows for optimal class separability and can be applied to optimize other methods of chromatogram alignment. Copyright © 2015 John Wiley & Sons, Ltd.
Orientational Preference of Long, Multicenter Bonds in Radical Anion Dimers: A Case Study of π‐[TCNB]22−and π‐[TCNP]22−
Authors: Capdevila‐Cortada Marçal , Miller Joel S. , Novoa Juan J. 
Published: February 2015

AbstractThe similar shape and electronic structure of the radical anions of 1,2,4,5‐tetracyanopyrazine (TCNP) and 1,2,4,5‐tetracyanobenzene (TCNB) suggest a similar relative orientation for their long, multicenter carboncarbon bond in π‐[TCNP]22−and in π‐[TCNB]22−, in good accord with the Maximin Principle predictions. Instead, the two known structures of π‐[TCNP]22−have aD2h(θ=0°) and aC2(θ=30°) orientation (θbeing the dihedral angle that determines the rotation of one radical anion relative to the other along the axis that passes through center of the two six‐membered rings). The only known π‐[TCNB]22−structure has aC2(θ=60°) orientation. The origin of these preferences was investigated for both dimers by computing (at the RASPT2/RASSCF(30,28) level) the variation withθof the interaction energy (Eint) and the variation of theEintcomponents. It was found that: 1) a long, multicenter bond exists for all orientations; 2) theEint(θ) angular dependence is similar in both dimers; 3) for all orientations the electrostatic component dominates the value ofEint(θ), although the dispersion and bonding components also play a relevant role; and 4) the Maximin Principle curve reproduces well the shape of theEint(θ) curve for isolated dimers, although none of them reproduce the experimental preferences. Only after the (radical anion).−⋅⋅⋅cation+interactions are also included in the model aggregate are the experimental data reproduced computationally.
Calcium‐Catalyzed Carboarylation of Alkynes
Authors: Fu Liang , Niggemann Meike 
Published: February 2015

AbstractThe first transition‐metal‐free carboarylation of alkynes with commercial and readily available alcohols as alkylating agents was realized in the presence of an environmentally benign calcium catalyst. Thereby, a novel protocol for the one‐step synthesis of highly congested, all‐carbon tetrasubstituted alkenes, as incorporated in potentially bioactive, complex dihydronaphthalene, chromene and dihydroquinoline structures, is provided. The reaction features an unprecedented, particularly wide substrate scope, good functional‐group tolerance and simple experimental operation under mild reaction conditions.
Randomizing the Unfolded State of Peptides (and Proteins) by Nearest Neighbor Interactions between Unlike Residues
Authors: Toal Siobhan E. , Kubatova Nina , Richter Christian , Linhard Verena , Schwalbe Harald , Schweitzer‐Stenner Reinhard 
Published: February 2015

AbstractTo explore the influence of nearest neighbors on conformational biases in unfolded peptides, we combined vibrational and 2D NMR spectroscopy to obtain the conformational distributions of selected “GxyG” host–guest peptides in aqueous solution: GDyG, GSyG, GxLG, GxVG, where x/y=A, K, L, V. Large changes of conformational propensities were observed due to nearest‐neighbor interactions, at variance with the isolated pair hypothesis. We found that protonated aspartic acid and serine lose their above‐the‐average preference for turn‐like structures in favor of polyproline II (pPII) populations in the presence of neighbors with bulky side chains. Such residues also decrease the above‐the‐average pPII preference of alanine. These observations suggest that the underlying mechanism involves a disruption of the hydration shell. Thermodynamic analysis of 3J(HN,Hα) (T) data for each x,y residue reveals that modest changes in the conformational ensemble masks larger changes of enthalpy and entropy governing the pPII↔β equilibrium indicating a significant residue dependent temperature dependence of the peptides’ conformational ensembles. These results suggest that nearest‐neighbor interactions between unlike residues act as conformational randomizers close to the enthalpy–entropy compensation temperature, eliminating intrinsic biases in favor of largely balanced pPII/β dominated ensembles at physiological temperatures.