bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interannual to multidecadal Euro‐Atlantic blocking variability during winter and its relationship with extreme low temperatures in Europe
Authors: Rimbu Norel , Lohmann Gerrit , Ionita Monica 
Published: November 2014

AbstractThe dominant modes of blocking frequency variability in the Atlantic‐European region are evaluated for the 1871–2010 period. An Empirical Orthogonal Function (EOF) analysis of a two‐dimensional blocking indicator field reveals three dominant EOFs, describing about 35% of interannual to multidecadal blocking variability. The first EOF captures an out‐of‐phase blocking frequency anomaly over Greenland and Western Europe regions. The corresponding principal component time series is strongly correlated with the North Atlantic Oscillation index but shows also significant correlations with indices of the East Atlantic, Scandinavian, and East Atlantic‐Western Russia patterns. The second EOF shows a dominant center over the North Sea region as well as a less pronounced center with anomalies of the same sign over southeastern Greenland. The multidecadal variations of this mode of blocking variability are related with a basin wide North Atlantic sea surface temperature anomaly which projects partly on the Atlantic Multidecadal Oscillation (AMO). The third mode is an east‐west dipole of blocking frequency anomalies from Scandinavian and southern Greenland regions and shows enhanced variability at ~20 year time scales. The coherent variations of the time coefficients of this pattern with open solar flux suggest a possible solar influence on blocking variability at these time scales. Furthermore, the dominant patterns of blocking variability are related with distinct anomaly patterns in the occurrence of extreme low temperature events over Europe at interannual to multidecadal time scales. AMO as well as the solar signals was detected also in the corresponding extreme low temperature blocking patterns. We argue that multivariate analysis of blocking indicators gives additional information about blocking and related extreme climate phenomena variability and predictability comparative with classical sectorial approach.
Anthropogenically induced changes in twentieth century mineral dust burden and the associated impact on radiative forcing
Authors: Stanelle Tanja , Bey Isabelle , Raddatz Thomas , Reick Christian , Tegen Ina 
Published: November 2014

AbstractWe investigate the relative importance of climate change (CC) and anthropogenic land cover change (ALCC) for the dust emissions and burden changes between the late nineteenth century and today. For this purpose, the climate‐aerosol model ECHAM6‐HAM2 is complemented by a new scheme to derive potential dust sources at runtime using the vegetation cover provided by the land component JSBACH of ECHAM6. Dust emissions are computed online using information from the ECHAM6 atmospheric component. This allows us to account for changes in land cover and climate interactively and to distinguish between emissions from natural and agricultural dust sources. For today's climate we find that nearly 10% of dust particles are emitted from agricultural areas. According to our simulations, global annual dust emissions have increased by 25% between the late nineteenth century and today (e.g., from 729 Tg/a to 912 Tg/a). Globally, CC and ALCC (e.g., agricultural expansion) have both contributed to this change (56% and 40%, respectively). There are however large regional differences. For example, change in dust emissions in Africa are clearly dominated by CC. Global dust burden have increased by 24.5% since the late nineteenth century, which results in a clear‐sky radiative forcing at top of the atmosphere of −0.14 W/m2. Based on these findings, we recommend that both climate changes and anthropogenic land cover changes should be considered when investigating long‐term changes in dust emissions.
Tropical temperature trends in Atmospheric General Circulation Model simulations and the impact of uncertainties in observed SSTs
Authors: Flannaghan T. J. , Fueglistaler S. , Held I. M. , Po‐Chedley S. , Wyman B. , Zhao M. 
Published: November 2014

AbstractThe comparison of trends in various climate indices in observations and models is of fundamental importance for judging the credibility of climate projections. Tropical tropospheric temperature trends have attracted particular attention as this comparison may suggest a model deficiency. One can think of this problem as composed of two parts: one focused on tropical surface temperature trends and the associated issues related to forcing, feedbacks, and ocean heat uptake and a second part focusing on connections between surface and tropospheric temperatures and the vertical profile of trends in temperature. Here we focus on the atmospheric component of the problem. We show that two ensembles of Geophysical Fluid Dynamics Laboratory HiRAM model runs (similar results are shown for National Center for Atmospheric Research's CAM4 model) with different commonly used prescribed sea surface temperatures (SSTs), namely, the HadISST1 and “Hurrell” data sets, have a difference in upper tropical tropospheric temperature trends (∼0.1 K/decade at 300 hPa for the period 1984–2008) that is about a factor 3 larger than expected from moist adiabatic scaling of the tropical average SST trend difference. We show that this surprisingly large discrepancy in temperature trends is a consequence of SST trend differences being largest in regions of deep convection. Further, trends, and the degree of agreement with observations, not only depend on SST data set and the particular atmospheric temperature data set but also on the period chosen for comparison. Due to the large impact on atmospheric temperatures, these systematic uncertainties in SSTs need to be resolved before the fidelity of climate models' tropical temperature trend profiles can be assessed.
Asymmetric Synthesis of Bioxindole‐Substituted Hexahydrofuro[2,3‐b]furans via Hydroquinine Anthraquinone‐1,4‐diyl Diether‐Catalyzed Domino Annulation of Acylidenoxindoles/Isatins, Acylidenoxindoles and Allenoates
Authors: Yang Hai‐Bin , Zhao Yun‐zhou , Sang Rui , Wei Yin , Shi Min 
Published: November 2014

AbstractHydroquinine anthraquinone‐1,4‐diyl diether [(DHQ)2AQN]‐catalyzed unprecedented asymmetric domino annulation reactions of acylidenoxindoles/isatins, acylidenoxindoles and allenoates are disclosed in this communication, providing a facile access to hexahydrofuro[2,3‐b]furans containing four contiguous chiral centers in good to excellent yields along with good to excellent ee values and moderate to good dr values. Based on theoretical investigations, a concerted [3+2] ring‐closure process was proposed, in which steric hindrance and π–π stacking interaction between catalyst and substrate subtly co‐control the diastereoselectivity of the reaction.magnified image
Multi‐Enzymatic Synthesis of Optically Pure β‐Hydroxy α‐Amino Acids
Authors: Hibi Makoto , Kasahara Takuya , Kawashima Takashi , Yajima Hiroko , Kozono Shoko , Smirnov Sergey V. , Kodera Tomohiro , Sugiyama Masakazu , Shimizu Sakayu , Yokozeki Kenzo , Ogawa Jun 
Published: November 2014

AbstractA novel enzymatic production system of optically pure β‐hydroxy α‐amino acids was developed. Two enzymes were used for the system: an N‐succinyl L‐amino acid β‐hydroxylase (SadA) belonging to the iron(II)/α‐ketoglutarate‐dependent dioxygenase superfamily and an N‐succinyl L‐amino acid desuccinylase (LasA). The genes encoding the two enzymes are part of a gene set responsible for the biosynthesis of peptidyl compounds found in the Burkholderia ambifaria AMMD genome. SadA stereoselectively hydroxylated several N‐succinyl aliphatic L‐amino acids and produced N‐succinyl β‐hydroxy L‐amino acids, such as N‐succinyl‐L‐β‐hydroxyvaline, N‐succinyl‐L‐threonine, (2S,3R)‐N‐succinyl‐L‐β‐hydroxyisoleucine, and N‐succinyl‐L‐threo‐β‐hydroxyleucine. LasA catalyzed the desuccinylation of various N‐succinyl‐L‐amino acids. Surprisingly, LasA is the first amide bond‐forming enzyme belonging to the amidohydrolase superfamily, and has succinylation activity towards the amino group of L‐leucine. By combining SadA and LasA in a preparative scale production using N‐succinyl‐L‐leucine as substrate, 2.3 mmol of L‐threo‐β‐hydroxyleucine were successfully produced with 93% conversion and over 99% of diastereomeric excess. Consequently, the new production system described in this study has advantages in optical purity and reaction efficiency for application in the mass production of several β‐hydroxy α‐amino acids.magnified image
Updating the role played by immunotherapy for allergic rhinitis: meta‐analysis
Authors: Cingi Cemal , Muluk Nuray Bayar , Hanci Deniz , Ulusoy Seckin , Sahin Fezan 
Published: November 2014

BackgroundAlthough the effectiveness of allergen monotherapy immunotherapy for allergic rhinitis (AR) has been well established by many prior studies, other aspects of immunotherapy are still incompletely documented by high‐quality studies. The many published papers describe various results. The aim of the present study was to conduct a meta‐analysis on the effectiveness of allergen immunotherapy.MethodsA total of 56 homogeneous studies were included in the analysis. The inclusion criteria used to select articles were as follows: (1) placebo‐controlled clinical trials; (2) the use of immunotherapy; (3) participants and/or physicians were or were not blinded to immunotherapy or placebo assignment (single‐blinding, double‐blinding, or no‐blinding studies); and (4) randomization or not of those in the immunotherapy and placebo groups.ResultsBetween 2003 and 2013, 114 placebo‐controlled clinical trials were reported in Medline. Studies describing recovery rates in immunotherapy and placebo groups numbered 56. The distribution of such works was homogeneous (heterogeneity chi‐square = 16.11; degrees of freedom [df] = 55; p = 1.000). The extent of recovery in immunotherapy groups was 53.671‐fold greater than in placebo groups (Mantel‐Haenszel [M‐H] pooled risk ratio [RR] = 53.671; 95% confidence interval [CI], 36.981 to 77.893; z = 20.96; p < 0.001).ConclusionOur meta‐analysis suggests that immunotherapy is associated with a recovery rate 53.671‐fold that of placebo.
G‐Quartet‐Based Nanostructure for Mimicking Light‐Harvesting Antenna
Authors: Pu Fang , Wu Li , Ran Xiang , Ren Jinsong , Qu Xiaogang 
Published: November 2014

AbstractArtificial light‐harvesting systems have received great attention for use in photosynthetic and optoelectronic devices. Herein, a system involving G‐quartet‐based hierarchical nanofibers generated from the self‐assembly of guanosine 5′‐monophosphate (GMP) and a two‐step Förster resonance energy transfer (FRET) is presented that mimics natural light‐harvesting antenna. This solid‐state property offers advantages for future device fabrication. The generation of photocurrent under visible light shows it has potential for use as a nanoscale photoelectric device. The work will be beneficial for the development of light‐harvesting systems by the self‐assembly of supramolecular nanostructures.
Remote meta‐CH Olefination of Phenylacetic Acids Directed by a Versatile U‐Shaped Template
Authors: Deng Youqian , Yu Jin‐Quan 
Published: November 2014

Abstractmeta‐CH olefination of phenylacetic acid derivatives has been achieved using a commercially available nitrile‐containing template. The identification of N‐formyl‐protected glycine as the ligand (Formyl‐Gly‐OH) was crucial for the development of this reaction. Versatility of the template approach in accommodating macrocyclopalladation processes with different ring sizes is demonstrated.
Total Syntheses of Linear Polythiazole/Oxazole Plantazolicin A and Its Biosynthetic Precursor Plantazolicin B
Authors: Wilson Zoe E. , Fenner Sabine , Ley Steven V. 
Published: November 2014

AbstractPlantazolicin A, a linear decacyclic natural product, exhibits desirable selective activity against the causative agent of anthrax toxicity. The total synthesis of plantazolicin A and its biosynthetic precursor plantazolicin B was successfully achieved by an efficient, unified, and highly convergent route featuring dicyclizations to form 2,4‐concatenated oxazoles and the mild synthesis of thiazoles from natural amino acids. This report represents the first synthesis of plantazolicin B and includes the first complete characterization data for both natural products.
Squeezing Fluoride out of Water with a Neutral Bidentate Antimony(V) Lewis Acid
Authors: Hirai Masato , Gabbaï François P. 
Published: November 2014

AbstractBecause of hydration, fluoride ions in water typically elude complexation by neutral Lewis acids. Here, we show how this limitation can be overcome with a bidentate Lewis acid containing two antimony(V) centers. This derivative (2) is obtained by the simple reaction of 4,5‐bis(diphenylstibino)‐9,9‐dimethylxanthene (1) with two equivalents of 3,4,5,6‐tetrachlorobenzoquinone (o‐chloranil). It features two square‐pyramidal stiborane units oriented in a face‐to‐face fashion. Titration experiments show that this new bidentate Lewis acid binds fluoride in aqueous solutions containing 95 % water with a binding constant (K) of 700±30 M−1. The structure of the fluoride adduct confirms fluoride anion chelation between the two antimony centers.
Upper Limit of Nitrogen Content in Carbon Materials
Authors: Zhang Shiguo , Tsuzuki Seiji , Ueno Kazuhide , Dokko Kaoru , Watanabe Masayoshi 
Published: November 2014

AbstractNitrogen‐doped carbon materials (NDCs) play an important role in various fields. A great deal of effort has been devoted to obtaining carbon materials with a high nitrogen content; however, much is still unknown about the structure of the nitrogen‐doped materials and the maximum nitrogen content possible for such compounds. Here, we demonstrate an interesting relationship between the N/C molar ratio and the N content of NDCs. The upper limit for the nitrogen content of NDCs that might be achieved was estimated and found to strongly depend on the carbonization temperature (14.32 wt % at 1000 °C and 21.66 wt % at 900 °C), irrespective of the precursor or preparation conditions. Simulations suggest that, especially in the carbon architectures obtained at high temperatures, nitrogen atoms are always located on separate hexagon moieties in a graphitic configuration, thereby yielding a critical N/C molar ratio very close to the value estimated from the experimental results.
Copper‐Catalyzed Aerobic Oxidative Transformation of Ketone‐Derived N‐Tosyl Hydrazones: An Entry to Alkynes
Authors: Li Xianwei , Liu Xiaohang , Chen Huoji , Wu Wanqing , Qi Chaorong , Jiang Huanfeng 
Published: November 2014

AbstractA novel strategy involving Cu‐catalyzed oxidative transformation of ketone‐derived hydrazone moiety to various synthetic valuable internal alkynes and diynes has been developed. This method features inexpensive metal catalyst, green oxidant, good functional group tolerance, high regioselectivity and readily available starting materials. Oxidative deprotonation reactions were carried out to form internal alkynes and symmetrical diynes. Cross‐coupling reactions of hydrazones with halides and terminal alkynes were performed to afford functionalized alkynes and unsymmetrical conjugated diynes. A mechanism proceeding through a Cu‐carbene intermediate is proposed for the CC triple bond formation.
Size‐Controlled Construction of Magnetic Nanoparticle Clusters Using DNA‐Binding Zinc Finger Protein
Authors: Ryu Yiseul , Jin Zongwen , Lee Joong‐jae , Noh Seung‐hyun , Shin Tae‐Hyun , Jo Seong‐Min , Choi Joonsung , Park HyunWook , Cheon Jinwoo , Kim Hak‐Sung 
Published: November 2014

AbstractNanoparticle clusters (NPCs) have attracted significant interest owing to their unique characteristics arising from their collective individual properties. Nonetheless, the construction of NPCs in a structurally well‐defined and size‐controllable manner remains a challenge. Here we demonstrate a strategy to construct size‐controlled NPCs using the DNA‐binding zinc finger (ZnF) protein. Biotinylated ZnF was conjugated to DNA templates with different lengths, followed by incubation with neutravidin‐conjugated nanoparticles. The sequence specificity of ZnF and programmable DNA templates enabled a size‐controlled construction of NPCs, resulting in a homogeneous size distribution. We demonstrated the utility of magnetic NPCs by showing a three‐fold increase in the spin–spin relaxivity in MRI compared with Feridex. Furthermore, folate‐conjugated magnetic NPCs exhibited a specific targeting ability for HeLa cells. The present approach can be applicable to other nanoparticles, finding wide applications in many areas such as disease diagnosis, imaging, and delivery of drugs and genes.
Copper Sulfide Nanoparticles with Phospholipid‐PEG Coating for In Vivo Near‐Infrared Photothermal Cancer Therapy
Authors: Huang Yizhuan , Lai Yulian , Shi Saige , Hao Shufang , Wei Jingping , Chen Xiaolan 
Published: November 2014

AbstractIn this work, small sizes of hydrophobic copper sulfide nanoparticles (CuS NPs, ∼3.8 nm in diameter) have been successfully prepared from the reaction of copper chloride with sodium diethyldithiocarbamate (SDEDTC) inside a heated oleylamine solution. These CuS NPs displayed strong absorption in the 700–1100 nm near‐infrared (NIR) region. By coating CuS NPs with DSPE‐PEG2000 on the surface, the as‐synthesized CuS@DSPE‐PEG NPs exhibited good water solubility, significant stability and biocompatibility, as well as excellent photothermal conversion effects upon exposure to an 808 nm laser. After intravenous administration to mice, the CuS@DSPE‐PEG NPs were found to passively target to the tumor site, and tumor tissues could be ablated efficiency under laser irradiation. In addition, CuS@DSPE‐PEG NPs do not show significant toxicity by histological and blood chemistry analysis, and can be effectively excreted via metabolism. Our results indicated that CuS@DSPE‐PEG NPs can act as an ideal photothermal agent for cancer photothermal therapy.
Preparation of morusin from Ramulus mori and its effects on mice with transplanted H22 hepatocarcinoma
Authors: Wan Liang‐Ze , Ma Bin , Zhang Yu‐Qing 
Published: November 2014

AbstractIn this study, we used branches Ramulus mori from cultivated mulberry Husang‐32 (Morus multicaulis Perry) as the experimental material and anhydrous ethanol as the extraction solution to obtain the crude extract from the branch bark. The ethanolic extract was successively purified through a macroporous resin, Sephadex LH‐20, and semipreparative reversed‐phase high‐performance liquid chromatography (RP‐HPLC). The high‐purity monomer was identified as morusin by HPLC with diode array detection (HPLC‐DAD) and its UV spectrum. The contents of morusin exhibited almost no difference between the root and branch bark in Husang‐32, and morusin was not detected in the leaves. Morusin is able to inhibit the tumor growth of transplanted H22 hepatocarcinoma in mice and has no side effects. The fluorescence quantitative real‐time PCR (qRT‐PCR) results indicate that morusin has a marked inhibitory effect on liver cancer cells through a mechanism that may be related increases in the expression of p53, Survivin, CyclinB1, and Caspase‐3 and a decrease in NF‐κ B gene expression. The influence of this compound is more apparent in the Caspase‐3 and the NF‐κ B genes. © 2014 BioFactors, 40(6):636–645, 2014
pH control in biological systems using calcium carbonate
Authors: Salek S.S. , van Turnhout A.G. , Kleerebezem R. , van Loosdrecht M.C.M. 
Published: November 2014

ABSTRACTDue to its abundance, calcium carbonate (CaCO3) has high potentials as a source of alkalinity for biotechnological applications. The application of CaCO3 in biological systems as neutralizing agent is, however, limited due to potential difficulties in controlling the pH. The objective of the present study was to determine the dominant processes that control the pH in an acid‐forming microbial process in the presence of CaCO3. To achieve that, a mathematical model was made with a minimum set of kinetically controlled and equilibrium reactions that was able to reproduce the experimental data of a batch fermentation experiment using finely powdered CaCO3. In the model, thermodynamic equilibrium was assumed for all speciation, complexation and precipitation reactions whereas, rate limited reactions were included for the biological fatty acid production, the mass transfer of CO2 from the liquid phase to the gas phase and the convective transport of CO2 out of the gas phase. The estimated pH‐pattern strongly resembled the measured pH, suggesting that the chosen set of kinetically controlled and equilibrium reactions were establishing the experimental pH. A detailed analysis of the reaction system with the aid of the model revealed that the pH establishment was most sensitive to four factors: the mass transfer rate of CO2 to the gas phase, the biological acid production rate, the partial pressure of CO2 and the Ca+2 concentration in the solution. Individual influences of these factors on the pH were investigated by extrapolating the model to a continuously stirred‐tank reactor (CSTR) case. This case study indicates how the pH of a commonly used continuous biotechnological process could be manipulated and adjusted by altering these four factors. Achieving a better insight of the processes controlling the pH of a biological system using CaCO3 as its neutralizing agent can result in broader applications of CaCO3 in biotechnological industries. Biotechnol. Bioeng. 2015;112: 905–913. © 2014 Wiley Periodicals, Inc.
Integration of biological kinetics and computational fluid dynamics to model the growth of Nannochloropsis salina in an open channel raceway
Authors: Park Stephen , Li Yebo 
Published: November 2014

ABSTRACTMicroalgal growth and systemic productivity is not only affected by environmental conditions such as temperature, irradiance, and nutrient concentrations, but also by physical processes such as fluid flow and particulate sedimentation. Modeling and simulating the system is a cost‐effective way to predict the growth behavior under various environmental and physical conditions while determining effective engineering approaches to maximize productivity. Many mathematical models have been proposed to describe microalgal growth, while computational fluid dynamics (CFD) have been used to model the behavior of many fluid systems. Integrating the growth kinetics into a CFD model can help researchers understand the impact of a variety of parameters and determine what measures can be taken to overcome some obstacles in the aquaculture industry – self‐shading, biomass sedimentation, and contamination – which prevent the production of high biomass yields. The aim of this study was to integrate physical and environmental effects to predict space‐ and time‐dependent algal growth in industrial scale raceways. A commercial CFD software, ANSYS‐Fluent 14.5, was used to solve the proposed models in regards to fluid flow, heat transfer, and nutrient balance. User‐defined functions written in C language were used to incorporate the kinetic equations into a three‐dimensional standard k‐ε turbulence model of an open channel raceway system driven by a single paddlewheel. Simulated results were compared with light intensity, temperature, nutrient concentration, and algal biomass data acquired for 56 day from an industrial scale raceway pond constructed for the growth of Nannochloropsis salina and were observed to be in good agreement with one another. There was up to a 17.6% increase in simulated productivity when the incoming CO2 concentration was increased from 0.0006 to 0.150 g L−1, while the effect of paddlewheel velocity was not significant. Sensitivity analysis showed that the model was particularly sensitive to the species‐specific maximum growth rate, light attenuation coefficient, optimal growth temperature, half‐saturation constant for growth based on irradiance, and death coefficient. Biotechnol. Bioeng. 2015;112: 923–933. © 2014 Wiley Periodicals, Inc.