bluuebunny/crossref_metadata_2025_split huggingface dataset:
Van Allen Probes observations of unusually low frequency whistler mode waves observed in association with moderate magnetic storms: Statistical study
Authors: Cattell C. A. , Breneman A. W. , Thaller S. A. , Wygant J. R. , Kletzing C. A. 
Published: September 2015

AbstractWe show the first evidence for locally excited chorus at frequencies below 0.1 fce (electron cyclotron frequency) in the outer radiation belt. A statistical study of chorus during geomagnetic storms observed by the Van Allen Probes found that frequencies are often dramatically lower than expected. The frequency at peak power suddenly stops tracking the equatorial 0.5 fce and f/fce decreases rapidly, often to frequencies well below 0.1 fce (in situ and mapped to equator). These very low frequency waves are observed both when the satellites are close to the equatorial plane and at higher magnetic latitudes. Poynting flux is consistent with generation at the equator. Wave amplitudes can be up to 20 to 40 mV/m and 2 to 4 nT. We conclude that conditions during moderate to large storms can excite unusually low frequency chorus, which is resonant with more energetic electrons than typical chorus, with critical implications for understanding radiation belt evolution.
Positive tropical marine low‐cloud cover feedback inferred from cloud‐controlling factors
Authors: Qu Xin , Hall Alex , Klein Stephen A. , DeAngelis Anthony M. 
Published: September 2015

AbstractDifferences in simulations of tropical marine low‐cloud cover (LCC) feedback are sources of significant spread in temperature responses of climate models to anthropogenic forcing. Here we show that in models the feedback is mainly driven by three large‐scale changes—a strengthening tropical inversion, increasing surface latent heat flux, and an increasing vertical moisture gradient. Variations in the LCC response to these changes alone account for most of the spread in model‐projected 21st century LCC changes. A methodology is devised to constrain the LCC response observationally using sea surface temperature (SST) as a surrogate for the latent heat flux and moisture gradient. In models where the current climate's LCC sensitivities to inversion strength and SST variations are consistent with observed, LCC decreases systematically, which would increase absorption of solar radiation. These results support a positive LCC feedback. Correcting biases in the sensitivities will be an important step toward more credible simulation of cloud feedbacks.
Cluster observations of unusually high concentration of energetic O+ carried by flux ropes in the nightside high‐latitude magnetosheath during a storm initial phase
Authors: Duan Suping , Dai Lei , Wang Chi , Lui A. T. Y. , Liu Zhenxing , He Zhaohai , Zhang Yongcun , Dandouras I. , Reme H. 
Published: September 2015

AbstractWe present measurements from Cluster spacecraft to investigate the energetic singly charged oxygen ions, O+, within the flux ropes in the nightside high‐latitude magnetosheath during the initial phase of an intense storm on 24 October 2011. Three magnetic flux ropes were identified by Cluster 4 in the intervals from 20:10 UT to 20:20 UT. Unusually, large number density of energetic O+ ions at energy of tens of keV was detected within these flux ropes. The number density of O+ ions was above 0.1 cm−3 and the maximum value was about 0.25 cm−3, 1 order of magnitude larger than the ambient value (~0.01 cm−3) in the magnetosheath. The O+/H+ ratio is as large as ~0.08 within the flux ropes. Enhanced convection electric fields Ey (~10 mV/m) are associated with the flux rope and the high concentrations of energetic O+. The flux ropes, which are presumably produced by magnetic reconnection at the dayside magnetopause or cusp, are convected at a larger velocity than the tailward velocity of ambient flows in the magnetosheath. These observations together show that abundant energetic O+ ions are carried by the flux ropes toward tail in the nightside magnetosheath. Our observations present new evidence for a chain linking the dayside to the nightside in the global O+ transport process.
The nature of GPS differential receiver bias variability: An examination in the polar cap region
Authors: Themens David R. , Jayachandran P. T. , Langley Richard B. 
Published: September 2015

AbstractWhile modern GPS receiver differential code bias estimation techniques have become highly refined, they still demonstrate unphysical behavior, namely, notable solar cycle variability. This study investigates the nature of these seasonal and solar cycle bias variabilities in the polar cap region using single‐station bias estimation methods. It is shown that the minimization of standard deviation bias estimation technique is linearly dependent on the user's choice of shell height, where the sensitivity of this dependence varies significantly from 1 total electron content unit (1 TECU = 1016 el m−2) per 4000 km in solar minimum winter to in excess of 1 TECU per 90 km during solar maximum summer. Using an ionosonde, we find appreciable shell height variability resulting in bias variabilities of up to 2 TECU. Comparing northward face Resolute Incoherent Scatter Radar (RISR‐N) measurements to a collocated GPS station, we find that RISR‐derived GPS receiver biases vary seasonally but not with solar cycle. RMS differences between bias estimation methods and observation between 2009 and 2013 were found to range from 2.7 TECU to 3.4 TECU, depending on method. To account for the erroneous solar cycle variability of standard bias estimation approaches, we linearly fit these biases to sunspot number, removing the trend. RMS errors after sunspot detrending these biases are reduced to 1.91 TECU. Also, these ISR‐derived and sunspot‐detrended biases are fit to ambient temperature, where a significant correlation is found. By using these temperature‐fitted biases we further reduce RMS errors to 1.66 TECU. These results can be taken as further evidence of temperature‐dependent dispersion in the GPS cabling and antenna hardware.
Organic aerosol processing in tropical deep convective clouds: Development of a new model (CRM‐ORG) and implications for sources of particle number
Authors: Murphy B. N. , Julin J. , Riipinen I. , Ekman A. M. L. 
Published: September 2015

AbstractThe difficulty in assessing interactions between atmospheric particles and clouds is due in part to the chemical complexity of the particles and to the wide range of length and timescales of processes occurring simultaneously during a cloud event. The new Cloud‐Resolving Model with Organics (CRM‐ORG) addresses these interactions by explicitly predicting the formation, transport, uptake, and re‐release of surrogate organic compounds consistent with the volatility basis set framework within a nonhydrostatic, three‐dimensional cloud‐resolving model. CRM‐ORG incorporates photochemical production, explicit condensation/evaporation of organic and inorganic vapors, and a comprehensive set of four different mechanisms describing particle formation from organic vapors and sulfuric acid. We simulate two deep convective cloud events over the Amazon rain forest in March 1998 and compare modeled particle size distributions with airborne observations made during the time period. The model predictions agree well with the observations for Aitken mode particles in the convective outflow (10–14 km) but underpredict nucleation mode particles by a factor of 20. A strong in‐cloud particle formation process from organic vapors alone is necessary to reproduce even relatively low ultrafine particle number concentrations (~1500 cm−3). Sensitivity tests with variable initial aerosol loading and initial vertical aerosol profile demonstrate the complexity of particle redistribution and net gain or loss in the cloud. In‐cloud particle number concentrations could be enhanced by as much as a factor of 3 over the base case simulation in the cloud outflow but were never reduced by more than a factor of 2 lower than the base. Additional sensitivity cases emphasize the need for constrained estimates of surface tension and affinity of organic vapors to ice surfaces. When temperature‐dependent organic surface tension is introduced to the new particle formation mechanisms, the number concentration of particles decreases by 60% in the cloud outflow. These uncertainties are discussed in light of the other prominent challenges for understanding the interactions between organic aerosols and clouds. Recommendations for future theoretical, laboratory, and field work are proposed.
Asthma risk factors
Authors: Toskala Elina , Kennedy David W. 
Published: September 2015

BackgroundBronchial asthma is one of the most common chronic diseases in childhood, with a current prevalence of 6% to 9%, but a prevalence that is increasing at an alarming rate. Asthma is a complex genetic disorder with strong environmental influence. It imposes a growing burden on our society in terms of morbidity, quality of life, and healthcare costs. Despite large‐scale efforts, only a few asthma genes have been confirmed, suggesting that the genetic underpinning of asthma is highly complex.MethodsA review of the literature was performed regarding atopic and nonatopic asthma risk factors, including environmental risk factors and genetic studies in adults and children.ResultsSeveral environmental risk factors have been identified to increase the risk of developing asthma such as exposure to air pollution and tobaccos smoke as well as occupational risk factors. In addition atopy, stress, and obesity all can increases the risk for asthma in genetically susceptible persons.ConclusionAsthma represents a dysfunctional interaction with our genes and the environment to which they are exposed, especially in fetal and early infant life. The increasing prevalence of asthma in all age groups indicate that our living environment and immunity are in imbalance with each other reacting with airway inflammation to the environmental exposures and often non‐harmful proteins, such as allergens causing the current “asthma and allergy epidemic.” Because of the close relationship between asthma and chronic rhinosinusitis, it is important that otolaryngologists have a good understanding of asthma, the etiologic factors associated with disease, and its evaluation and management.
Metalloenzymartige Zeolithe als Lewis‐Säure‐Katalysatoren für die C‐C‐Bindungsbildung
Authors: Van de Vyver Stijn , Román‐Leshkov Yuriy 
Published: September 2015

AbstractIn den letzten Jahren wurde der Verwendung von metalloenzymartigen Zeolithen als Lewis‐Säure‐Katalysatoren für C‐C‐Kupplungen zunehmende Aufmerksamkeit geschenkt. Insbesondere die Beobachtung, dass hydrophobe Zeolithe mit isolierten Metallzentren im Gerüst direkte Aldolkondensationen ermöglichen, hat die Entwicklung von Katalyseverfahren für die Herstellung von Chemikalien ausgehend von aus Biomasse stammenden Verbindungen angestoßen. Die Entdeckung von neuen Diels‐Alder‐Cycloadditions‐/Dehydratisierungswegen sowie experimentelle und rechnerische Untersuchungen von Lewis‐Säure‐katalysierten Carbonyl‐En‐Reaktionen haben die Entwicklung dieses schnell wachsenden Forschungsgebietes weiter vorangetrieben.
Asperchalasine A, a Cytochalasan Dimer with an Unprecedented Decacyclic Ring System, from Aspergillus flavipes
Authors: Zhu Hucheng , Chen Chunmei , Xue Yongbo , Tong Qingyi , Li Xiao‐Nian , Chen Xintao , Wang Jianping , Yao Guangmin , Luo Zengwei , Zhang Yonghui 
Published: September 2015

AbstractAsperchalasine A (1), the first cytochalasan dimer featuring a unique decacyclic 5/6/11/5/5/6/5/11/6/5 ring system consisting of 20 chiral centers, was isolated from the culture broth of Aspergillus flavipes. Three biogenetically related intermediates, asperchalasines B–D (2–4), were also isolated. Their structures, including their absolute configurations, were elucidated using a combination of HRESIMS, NMR, ECD, molecular modeling, and single‐crystal X‐ray diffraction techniques. Compound 1, which possesses an unprecedented 13‐oxatetracyclo[7.2.1.12,5.01,6]tridec‐8,12‐dione core structure, is the first example of a dimeric cytochalasan alkaloid. The biogenetic pathways of 1–4 were described starting from the co‐isolated compounds 5 and 6. More importantly, 1 induced significant G1‐phase cell cycle arrest by selectively inhibiting cyclin A, CDK2 and CDK6 in cancerous, but not normal, cells, highlighting it as a potentially selective cell cycle regulator against cancer cells.
Metalloenzyme‐Like Zeolites as Lewis Acid Catalysts for CC Bond Formation
Authors: Van de Vyver Stijn , Román‐Leshkov Yuriy 
Published: September 2015

AbstractThe use of metalloenzyme‐like zeolites as Lewis acid catalysts for CC bond formation reactions has received increasing attention over the past few years. In particular, the observation of direct aldol condensation reactions enabled by hydrophobic zeolites with isolated framework metal sites has encouraged the development of catalytic approaches for producing chemicals from biomass‐derived compounds. The discovery of new Diels–Alder cycloaddition/dehydration routes and experimental and computational studies of Lewis acid catalyzed carbonyl–ene reactions have given a further boost to this rapidly evolving field.
Enhancing pentose phosphate pathway in Corynebacterium glutamicum to improve l‐isoleucine production
Authors: Ma Wenjian , Wang Jianli , Li Ye , Hu Xiaoqing , Shi Feng , Wang Xiaoyuan 
Published: September 2015

AbstractThree genes, gnd, pgl, and fbp, relevant to the pentose phosphate pathway (PPP) were overexpressed in Corynebacterium glutamicum IWJ001, leading to increase of l‐isoleucine production. The transcriptional levels of gnd, pgl, and fbp significantly increased in IWJ001/pDXW‐8‐gnd‐fbp‐pgl. Compared with the control strain IWJ001/pDXW‐8, intracellular NADPH/NADP+ ratios in IWJ001/pDXW‐8‐gnd and IWJ001/pDXW‐8‐gnd‐fbp cells grown for 36 H increased threefold and fourfold, respectively, indicating that overexpression of gnd and fbp redirected the carbon flux to PPP. Intracellular NADPH/NADP+ ratio in IWJ001/pDXW‐8‐gnd‐fbp‐pgl grown for 36 H was similar to IWJ001/pDXW‐8, suggesting that the NADPH produced by PPP could be quickly consumed for l‐isoleucine production. 10.9 and 28.96 g/L of l‐isoleucine was produced in IWJ001/pDXW‐8‐gnd‐fbp‐pgl in shake flask cultivation and fed‐batch fermentation, respectively. In addition, IWJ001/pDXW‐8‐gnd‐fbp‐pgl grew fast, its dry cell weight reached 49 g/L after 48 H, whereas the start strain IWJ001/pDXW‐8 reached only 40 g/L. After 96 H fermentation, l‐isoleucine yield on glucose in IWJ001/pDXW‐8‐gnd‐fbp‐pgl reached 0.138 g/g. The results demonstrate that carbon flux redirection to PPP is an efficient approach to enhance l‐isoleucine production in C. glutamicum.
Early definite stent thrombosis with everolimus‐eluting stents
Authors: Naito Ryo , Miyauchi Katsumi , Konishi Hirokazu , Tsuboi Shuta , Okazaki Shinya , Daida Hiroyuki 
Published: September 2015

Key Clinical MessageStent thrombosis (ST) is a serious complication of percutaneous coronary intervention. Several factors are associated with ST, and combination of these factors increase the risk, even in everolimus‐eluting stents, which have low risk of ST. We experienced a case of ST caused by limited coronary flow and resistance to antiplatelet agent.
Bubble Mobilization Pressure in a Small‐Diameter Tube
Authors: Uchiyama Hiroki , Kariyasaki Akira , Kagawa Masazumi , Yamasaki Yoshikazu , Matsukuma Yosuke , Morooka Shigeharu 
Published: September 2015

AbstractThe mobilization pressure was measured for a train of bubbles in a capillary tube when the liquid film forming between the bubble surface and the inner surface of the duct does (Case B) and does not cover the bubble surface (Case A). In Case A, the measured bubble mobilization pressure mostly agreed with the estimated capillary pressure for different numbers of bubbles in the duct. In Case B, the bubble mobilization pressure was lower, with a larger scatter than in Case A. Increasing the number of bubbles caused the mobilization pressure to converge to the Case B results. Factors that affect the mobilization pressure were considered.
ChemInform Abstract: Titanium Migration Driven by Li Vacancies in Li1‐xTi2O4 Spinel.
Authors: Kitada A. , Arevalo‐Lopez A. M. , Attfield J. P. 
Published: September 2015

AbstractGentle oxidation of LiTi2O4 with H2O at 25 °C results in Li‐deficient Li1‐xTi2O4 (x = 0.67) without decomposition to other Ti oxides.
ChemInform Abstract: Synthesis and Up‐Conversion Luminescence of Yb3+/Er3+/Tm3+ Doped Ca9Y(PO4)7.
Authors: Du Shanshan , Wang Deyin , Wang Yuhua , Xin Shuangyu , Qiang QinPing , Ma Xinlong 
Published: September 2015

AbstractYb3+/Er3+, Yb3+/Tm3+, or Yb3+/Er3+/Tm3+ (25, 1, and 0.5 mol%, resp.) co‐doped Ca9Y(PO4)7 are prepared by hydrothermal reaction of a stoichiometric solution of CaCO3, Y2O3, and lanthanide oxides in HNO3 to which (NH4)2HPO4 is added at a controlled pH of 8 (autoclave, 200 °C, 10 h) followed by annealing in air (850 °C, 2 h).
ChemInform Abstract: Synthetic Progress Toward Azadirachtins. Part 2. Enantio‐ and Diastereoselective Synthesis of the Right‐Wing Fragment of 11‐epi‐Azadirachtin I.
Authors: Tan Ceheng , Chen Wei , Mu Xinpeng , Chen Qi , Gong Jianxian , Luo Tuoping , Yang Zhen 
Published: September 2015

AbstractThe reaction of silyl glyoxylate (I) with allylzinc bromide and β‐lactone (III) leads to benzoate (IV), which is used for the multistep preparation of the furopyran moiety (XII) of azadirachtins.
ChemInform Abstract: Enantioselective α‐Amination of 1,3‐Dicarbonyl Compounds in Batch and Flow with Immobilized Thiourea Organocatalysts.
Authors: Kasaplar Pinar , Ozkal Erhan , Rodriguez‐Escrich Carles , Pericas Miquel A. 
Published: September 2015

AbstractThe polymer‐supported bifunctional thiourea organocatalyst PSTU is not irreversibly deactivated by the azodicarboxylates (II) used.
ChemInform Abstract: Catalytic Enantioselective Intramolecular Aza‐Diels—Alder Reactions.
Authors: Min Chang , Lin Chih‐Tsung , Seidel Daniel 
Published: September 2015

AbstractHighly annulated heterocycles are obtained via intramolecular Povarov reaction promoted by a readily available chiral Broensted acid catalyst.
ChemInform Abstract: Intramolecular Insertions into Unactivated C(sp3)—H Bonds by Oxidatively Generated β‐Diketone‐α‐Gold Carbenes: Synthesis of Cyclopentanones.
Authors: Wang Youliang , Zheng Zhitong , Zhang Liming 
Published: September 2015

AbstractFor the first time, oxidatively generated β‐diketone‐α‐gold carbenes are intramolecularly inserted into unactivated C(sp3)—H bonds using ynones as substrates.
ChemInform Abstract: Broadening the Chemical Scope of Laccases: Selective Deprotection of N‐Benzyl Groups.
Authors: Martinez‐Montero Lia , Diaz‐Rodriguez Alba , Gotor Vicente , Gotor‐Fernandez Vicente , Lavandera Ivan 
Published: September 2015

AbstractLaccase from Trametes versicolor along with TEMPO is found to be a very efficient catalytic system for the deprotection of N‐benzylated primary amines using oxygen as a mild oxidant in aqueous medium.
ChemInform Abstract: A New Approach to Nitrones Through Cascade Reaction of Nitro Compounds Enabled by Visible Light Photoredox Catalysis.
Authors: Lin Cheng‐Wei , Hong Bor‐Cherng , Chang Wan‐Chen , Lee Gene‐Hsiang 
Published: September 2015

AbstractA series of nitrones (III) is readily prepared by a photocatalytic reaction of nitro compounds (I) with aldehydes (II) in the presence of iBu‐N(iPr)2 as base.
ChemInform Abstract: Bidirectional Approach to Symmetrical Spiro‐1,3‐bisketone via Grignard Reaction and Two Fold Ring‐Closing Metathesis as Key Steps.
Authors: Kotha Sambasivarao , Ali Rashid , Dipak Mirtunjay Kumar 
Published: September 2015

AbstractSymmetrical spiro‐1,3‐bisketone (IV) is synthesized by ring‐closure metathesis reaction of tetraene (I) obtained by Grignard reaction of a dialkenyl compound and allylmagnesium bromide.
ChemInform Abstract: Pinacolatoboron Fluoride (pinBF) is an Efficient Fluoride Transfer Agent for Diastereoselective Synthesis of Benzylic Fluorides.
Authors: Cresswell Alexander J. , Davies Stephen G. , Figuccia Aude L. A. , Fletcher Ai M. , Heijnen Dorus , Lee James A. , Morris Melloney J. , Kennett Alice M. R. , Roberts Paul M. , Thomson James E. 
Published: September 2015

AbstractPinacolatoboron fluoride, generated in situ from bis(O‐trimethylsilyl)pinacol and BF3·OEt2 is an efficient fluoride transfer reagent for epoxide ring‐opening.
ChemInform Abstract: Copper‐Catalyzed Aerobic Oxidative C—C Bond Cleavage of Unstrained Ketones with Air and Amines.
Authors: Zhou Wang , Fan Wenyou , Jiang Qijian , Liang Yu‐Feng , Jiao Ning 
Published: September 2015

AbstractAmide and oxoamides are easily synthesized from the title reaction of both simple and cyclic ketones.
ChemInform Abstract: Step Economical Synthesis of O‐Aryl Benzamides via C—H Activation Relayed by the in situ Installation of Directing Group: A Multicomponent Method.
Authors: Liu Yunyun , Zhang Yi , Huang Meiying , Wan Jie‐Ping 
Published: September 2015

AbstractA concise multicomponent one‐step method for the synthesis of 2,6‐biarylated (IV),(VI) or 6‐arylated benzamides (VIII) starting from 8‐aminoquinoline, benzoyl chlorides, and various iodobenzenes is established.
ChemInform Abstract: Stereoselective Preparation of Polyfunctional Alkenylindium(III) Halides and Their Cross‐Coupling with Unsaturated Halides.
Authors: Shen Zhi‐Liang , Knochel Paul 
Published: September 2015

AbstractThe stereoselective synthesis of cyclic and acyclic (E)‐ or (Z)‐alkenylindium halides is described.
ChemInform Abstract: Eco‐Friendly Approach to Tetrasubstituted Diazodihydrofuranones: Valuable Precursors of Oxetane Derivatives and Other Heterocyclic Compounds.
Authors: Galkina Olesia S. , Maas Gerhard , Rodina Liudmila L. , Nikolaev Valerij A. 
Published: September 2015

AbstractThe developed reaction sequence provides 2,2,5,5‐tetraalkyl, 2,2,5,5‐tetraaryl as well as regioisomeric 2,2‐diaryl‐5,5‐dimethyl and 2,2‐dimethyl‐5,5‐diaryldiazofuranones.
ChemInform Abstract: Enantioselective Synthesis of Tertiary α‐Chloro Esters by Non‐covalent Catalysis.
Authors: Liu Richard Y. , Wasa Masayuki , Jacobsen Eric N. 
Published: September 2015

AbstractThe enantioselective α‐chlorination of silyl ketene acetals with NCS is achieved in the presence of the chiral squaramide catalyst.
ChemInform Abstract: Zinc and Trimethylsilyl Chloride Mediated Synthesis of 2,3,5‐Trisubstituted Pyrrole Diesters from Nitriles and Ethyl Bromoacetate.
Authors: Rao H. Surya Prakash , Desai Avinash 
Published: September 2015

AbstractAn efficient synthesis of pyrrole diesters from readily available aromatic, benzylic, and aliphatic nitriles with ethyl bromoacetate takes place if the amount of the catalyst is 50 mol%.
ChemInform Abstract: [3 + 2] Cycloaddition of Arynes with CF3CHN2: Access to 3‐Trifluoromethyl‐1H‐indazoles.
Authors: Sun Long , Nie Jing , Zheng Yan , Ma Jun‐An 
Published: September 2015

AbstractA general and practical methodology for the formation of 3‐trifluoromethylindazoles under mild reaction conditions is developed.
ChemInform Abstract: One‐Pot Synthesis of Highly Functionalized Benzimidazolylisophthalates and (2E)‐2‐Ethylidene‐(1H)‐pyridinecarboxylates by Ultrasound‐Promoted Multicomponent Reactions.
Authors: Eleftheriadis Nicolaos , Kasapidou Paraskevi M. , Stephanidou‐Stephanatou Julia , Tsoleridis Constantinos A. , Hadjipavlou‐Litina Dimitra J. , Kontogiorgis Christos , Pritsa Agathi , Papadopoulos Athanasios 
Published: September 2015

AbstractStarting from 3‐formylchromones, acetonedicarboxylates and 2‐aminobenzimidazole or aryl amines an efficient one‐step method to new hydroxyaroylbenzimidazole or hydroxyaroylpyridinecarboxylate derivatives, respectively, is described.
ChemInform Abstract: Synthesis and Anticancer Activities of Thiazoles, 1,3‐Thiazines, and Thiazolidine Using Chitosan‐Grafted‐Poly(vinylpyridine) as Basic Catalyst.
Authors: Riyadh Sayed M. , Gomha Sobhi M. , Mahmmoud Elmahdi A. , Elaasser Mahmoud M. 
Published: September 2015

AbstractA series of thiazoles (III) and (V), 1,3‐thiazines (IX), and thiazolidine (VII) is prepared in the presence of an environmentally friendly basic chitosan‐grafted‐poly(vinylpyridine) catalyst.