bluuebunny/crossref_metadata_2025_split huggingface dataset:
The impact of static stress change, dynamic stress change, and the background stress on aftershock focal mechanisms
Authors: Hardebeck Jeanne L. 
Published: October 2014

AbstractThe focal mechanisms of earthquakes in Southern California before and after four M ≥ 6.7 main shocks provide insight into how fault systems respond to stress and changes in stress. The main shock static stress changes have two observed impacts on the seismicity: changing the focal mechanisms in a given location to favor those aligned with the static stress change and changing the spatial distribution of seismicity to favor locations where the static stress change aligns with the background stress. The aftershock focal mechanisms are significantly aligned with the static stress changes for absolute stress changes of ≥ 0.02 MPa, for up to ~20 years following the main shock. The dynamic stress changes have similar, although smaller, effects on the local focal mechanisms and the spatial seismicity distribution. Dynamic stress effects are best observed at long periods (30–60 s) and for metrics based on repeated stress cycling in the same direction. This implies that dynamic triggering operates, at least in part, through cyclic shear stress loading in the direction of fault slip. The background stress also strongly controls both the preshock and aftershock mechanisms. While most aftershock mechanisms are well oriented in the background stress field, 10% of aftershocks are identified as poorly oriented outliers, which may indicate limited heterogeneity in the postmain shock stress field. The fault plane orientations of the outliers are well oriented in the background stress, while their slip directions are not, implying that the background stress restricts the distribution of available fault planes.
Proxy interpretation of coral‐recorded seawater δ18O using 1‐D model forced by isotope‐incorporated GCM in tropical oceanic regions
Authors: Liu Gang , Kojima Keitaro , Yoshimura Kei , Oka Akira 
Published: October 2014

AbstractThe oxygen isotopic ratio in the seawater (δ18Osw) recorded in δ18O of coral skeleton for several centuries in tropical regions is an important variable for reconstructing the past climate. However, the relationship between δ18Osw and hydrological balance has not been clearly uncovered yet. In this study, a one‐dimensional ocean budget model forced by the global quasi‐reanalysis isotope data, which is the output of an isotope‐incorporated global spectral model, is employed to simulate δ18Osw. The results from the simulations are compared with 31 coral records in tropical oceanic regions. The 1‐D model successfully reproduces δ18Osw in 21 coral records, indicating these corals have the potential to reconstruct the local hydrological budget. The results also confirm that the reproducibility of the 1‐D model generally increases with the annual precipitation variability. However, in the regions where the precipitation variability is less, it is more difficult to reconstruct climatic information from the δ18Osw, since the nonlocal physical processes unaccounted for in the 1‐D model may affect δ18Osw. The sensitivity analysis of the 1‐D model shows that in tropical oceanic regions, the large‐scale precipitation is the dominant factor for δ18Osw, confirming that δ18Osw recorded in the coral records is a proxy for the precipitation anomaly. This study implies that δ18Osw is more closely associated with precipitation and local water isotope budget in tropical oceanic regions than elsewhere, and that the 1‐D model is a useful approach for the proxy interpretation in tropical oceanic regions.
On the origin of the Vastitas Borealis Formation in Chryse and Acidalia Planitiae, Mars
Authors: Salvatore M. R. , Christensen P. R. 
Published: October 2014

AbstractThe geologic history of the northern plains of Mars has been extensively debated. Specifically, the Vastitas Borealis Formation (VBF) represents an enigmatic surface unit that exhibits flow morphologies at its boundary, extensive surface fracturing, tens of thousands of small mounds, and unique crater morphologies. Here we test the hypothesis that the VBF in the region of Chryse and Acidalia Planitiae, Mars, originated through the compaction and later expulsion of fluid‐laden sediments sourced from the shallow subsurface. We find that the morphological, thermophysical, and spectral properties of the VBF marginal unit, in addition to the recent identification of fine‐grained sedimentary layers in the shallow subsurface, are all consistent with such a formation mechanism. Estimates of volume loss based on “collar‐like” morphologies present on high‐standing buttes suggest that a minimum fluid volume of ~13,500 km3 was expelled from the subsurface, making the VBF a significant ancient hydrologic reservoir on the Martian surface. This formation mechanism lends additional insight into the sedimentary and aqueous history of the northern plains of Mars and unites morphologic, spectral, thermophysical, and structural observations under one consistent formation hypothesis.
Monitoring motion and measuring relative position of the Chang'E‐3 rover
Authors: Liu Qinghui , Zheng Xin , Huang Yong , Li Peijia , He Qingbao , Wu Yajun , Guo Li , Tang Mingle 
Published: October 2014

AbstractSame‐beam very long baseline interferometry observations were performed between the rover and the lander of Chang'E‐3 and differential phase delay data were obtained with the minimum random error of about 0.03 ps. These data were used to monitor the rover motions, as small as several centimeters, including movement, turning, and attitude adjustment. The relative position between the rover and the lander was precisely measured with an accuracy of 1 m, which is an improvement of 10 times compared with that of the Apollo project.
Wind‐driven nearshore sediment resuspension in a deep lake during winter
Authors: Reardon Kristin E. , Bombardelli Fabián A. , Moreno‐Casas Patricio A. , Rueda Francisco J. , Schladow S. Geoffrey 
Published: October 2014

AbstractOngoing public concern over declining water quality at Lake Tahoe, California‐Nevada (USA) led to an investigation of wind‐driven nearshore sediment resuspension that combined field measurements and modeling. Field data included: wind speed and direction, vertical profiles of water temperature and currents, nearbed velocity, lakebed sediment characteristics, and suspended sediment concentration and particle size distribution. Bottom shear stress was computed from ADV‐measured nearbed velocity data, adapting a turbulent kinetic energy method to lakes, and partitioned according to its contributions attributed to wind‐waves, mean currents, and random motions. When the total shear stress exceeded the critical shear stress, the contribution to overall shear stress was about 80% from wind‐waves and 10% each from mean currents and random motions. Therefore, wind‐waves were the dominant mechanism resulting in sediment resuspension as corroborated by simultaneous increases in shear stress and total measured sediment concentration. The wind‐wave model STWAVE was successfully modified to simulate wind‐wave‐induced sediment resuspension for viscous‐dominated flow typical in lakes. Previous lake applications of STWAVE have been limited to special instances of fully turbulent flow. To address the validity of expressions for sediment resuspension in lakes, sediment entrainment rates were found to be well represented by a modified 1991 García and Parker formula. Last, in situ measurements of suspended sediment concentration and particle size distribution revealed that the predominance of fine particles (by particle count) that most negatively impact clarity was unchanged by wind‐related sediment resuspension. Therefore, we cannot assume that wind‐driven sediment resuspension contributes to Lake Tahoe's declining nearshore clarity.
Multisensor earth observations to characterize wetlands and malaria epidemiology in Ethiopia
Authors: Midekisa Alemayehu , Senay Gabriel B. , Wimberly Michael C. 
Published: October 2014

AbstractMalaria is a major global public health problem, particularly in Sub‐Saharan Africa. The spatial heterogeneity of malaria can be affected by factors such as hydrological processes, physiography, and land cover patterns. Tropical wetlands, for example, are important hydrological features that can serve as mosquito breeding habitats. Mapping and monitoring of wetlands using satellite remote sensing can thus help to target interventions aimed at reducing malaria transmission. The objective of this study was to map wetlands and other major land cover types in the Amhara region of Ethiopia and to analyze district‐level associations of malaria and wetlands across the region. We evaluated three random forests classification models using remotely sensed topographic and spectral data based on Shuttle Radar Topographic Mission (SRTM) and Landsat TM/ETM+ imagery, respectively. The model that integrated data from both sensors yielded more accurate land cover classification than single‐sensor models. The resulting map of wetlands and other major land cover classes had an overall accuracy of 93.5%. Topographic indices and subpixel level fractional cover indices contributed most strongly to the land cover classification. Further, we found strong spatial associations of percent area of wetlands with malaria cases at the district level across the dry, wet, and fall seasons. Overall, our study provided the most extensive map of wetlands for the Amhara region and documented spatiotemporal associations of wetlands and malaria risk at a broad regional level. These findings can assist public health personnel in developing strategies to effectively control and eliminate malaria in the region.
SNOT‐22 quality of life domains differentially predict treatment modality selection in chronic rhinosinusitis
Authors: DeConde Adam S. , Mace Jess C. , Bodner Todd , Hwang Peter H. , Rudmik Luke , Soler Zachary M. , Smith Timothy L. 
Published: October 2014

BackgroundPrior study demonstrated that baseline 22‐item Sino‐Nasal Outcome Test (SNOT‐22) aggregate scores accurately predict selection of surgical intervention in patients with chronic rhinosinusitis (CRS). Factor analysis of the SNOT‐22 survey has identified five distinct domains that are differentially impacted by endoscopic sinus surgery (ESS). This study sought to quantify SNOT‐22 domains in patient cohorts electing both surgical or medical management and postinterventional change in these domains.MethodsCRS patients were prospectively enrolled into a multi‐institutional, observational cohort study. Subjects elected continued medical management or ESS. SNOT‐22 domain scores at baseline were compared between treatment cohorts. Postintervention domain score changes were evaluated in subjects with at least six‐month follow‐up.ResultsA total of 363 subjects were enrolled with 72 (19.8%) electing continued medical management, whereas 291 (80.2%) elected ESS. Baseline SNOT‐22 domain scores were comparable between treatment cohorts in sinus‐specific domains (rhinologic, extranasal rhinologic, and ear/facial symptoms; p > 0.050); however, the surgical cohort reported significantly higher psychological (mean ± standard deviation [SD]: 16.0 ± 8.4 vs 12.0 ± 7.1; p < 0.001) and sleep dysfunction (13.7 ± 6.8 vs 10.5 ± 6.2; p < 0.001) than the medical cohort. Effect sizes for ESS varied across domains with rhinologic and extranasal rhinologic symptoms experiencing the greatest gains (1.067 and 0.997, respectively), whereas psychological and sleep dysfunction experiencing the smallest improvements (0.805 and 0.818, respectively). Patients experienced greater mean improvements after ESS in all domains compared to medical management (p < 0.001).ConclusionSubjects electing ESS report higher sleep and psychological dysfunction compared to medical management but have comparable sinus‐specific symptoms. Subjects undergoing ESS experience greater gains compared to medical management across all domains; however, these gains are smallest in the psychological and sleep domains.
Synthesis and Ligand Modification Chemistry of a Molybdenum Dinitrogen Complex: Redox and Chemical Activity of a Bis(imino)pyridine Ligand
Authors: Margulieux Grant W. , Turner Zoë R. , Chirik Paul J. 
Published: October 2014

AbstractThe bis(imino)pyridine 2,6‐(2,6‐iPr2‐C6H3NCPh)2‐C5H3N (iPrBPDI) molybdenum dinitrogen complex, [{(iPrBPDI)Mo(N2)}2(μ2,η1,η1‐N2)] has been prepared and contains both weakly (terminal) and modestly (bridging) activated N2 ligands. Addition of ammonia resulted in sequential NH bond activations, thus forming bridging parent imido (μ‐NH) ligands with concomitant reduction of one of the imines of the supporting chelate. Using primary and secondary amines, model intermediates have been isolated that highlight the role of metal–ligand cooperativity in NH3 oxidation.
Diagnosis of Toxoplasmosis Using a Synthetic Glycosylphosphatidylinositol Glycan
Authors: Götze Sebastian , Azzouz Nahid , Tsai Yu‐Hsuan , Groß Uwe , Reinhardt Anika , Anish Chakkumkal , Seeberger Peter H. , Varón Silva Daniel 
Published: October 2014

AbstractAround 2 billion people worldwide are infected with the apicomplexan parasite Toxoplasma gondii which induces a variety of medical conditions. For example, primary infection during pregnancy can result in fetal death or mental retardation of the child. Diagnosis of acute infections in pregnant women is challenging but crucially important as the drugs used to treat T. gondii infections are potentially harmful to the unborn child. Better, faster, more reliable, and cheaper means of diagnosis by using defined antigens for accurate serological tests are highly desirable. Synthetic pathogen‐specific glycosylphosphatidylinositol (GPI) glycan antigens are diagnostic markers and have been used to distinguish between toxoplasmosis disease states using human sera.
Supramolecular Architectures from Bent‐Core Dendritic Molecules
Authors: Cano Miguel , Sánchez‐Ferrer Antoni , Serrano José Luis , Gimeno Nélida , Ros M. Blanca 
Published: October 2014

AbstractControl of the self‐assembly of small molecules to generate architectures with diverse shapes and dimensions is a challenging research field. We report unprecedented results on the ability of ionic, bent dendritic molecules to aggregate in water. A range of analytical techniques (TEM, SEM, SAED, and XRD) provide evidence of the formation of rods, spheres, fibers, helical ribbons, or tubules from achiral molecules. The compact packing of the bent‐core structures, which promotes the bent‐core mesophases, also occurs in the presence of a poor solvent to provide products ranging from single objects to supramolecular gels. The subtle balance of molecule/solvent interactions and appropriate molecular designs also allows the transfer of molecular conformational chirality to morphological chirality in the overall superstructure. Functional motifs and controlled morphologies can be combined, thereby opening up new prospects for the generation of nanostructured materials through a bottom‐up strategy.
Isolation of a Three‐Coordinate Boron Cation with a Boron–Sulfur Double Bond
Authors: Franz Daniel , Irran Elisabeth , Inoue Shigeyoshi 
Published: October 2014

AbstractThe reaction of the bulky bis(imidazolin‐2‐iminato) ligand precursor (1,2‐(LMesNH)2‐C2H4)[OTs]2 (12+ 2[OTs]−; LMes=1,3‐dimesityl imidazolin‐2‐ylidene, OTs=p‐toluenesulfonate) with lithium borohydride yields the boronium dihydride cation (1,2‐(LMesN)2‐C2H4)BH2[OTs] (2+ [OTs]−). The boronium cation 2+ [OTs]− reacts with elemental sulfur to give the thioxoborane salt (1,2‐(LMesN)2‐C2H4)BS[OTs] (3+ [OTs]−). The hitherto unknown compounds 12+ 2[OTs]−, 2+ [OTs]−, and 3+ [OTs]− were fully characterized by spectroscopic methods and single‐crystal X‐ray diffraction. Moreover, DFT calculations were carried out to elucidate the bonding situation in 2+ and 3+. The theoretical, as well as crystallographic studies reveal that 3+ is the first example for a stable cationic complex of three‐coordinate boron that bears a BS double bond.
Dendritic Ionic Liquids Based on Imidazolium‐Modified Poly(aryl ether) Dendrimers
Authors: Qin Tianyi , Li Xuying , Chen Jinping , Zeng Yi , Yu Tianjun , Yang Guoqiang , Li Yi 
Published: October 2014

AbstractA series of dendritic ionic liquids (DILs) based on imidazolium‐modified poly(aryl ether) dendrimers IL‐Br‐Gn (n=0–3) were synthesized by a modified convergent approach and “click” chemistry. The resulting DILs exhibited high thermal resistance with decomposition temperatures up to 270 °C and low glass transition temperatures in the range of approximately −5–0 °C. All IL‐Br‐Gn were found to be miscible with water at any ratio and could encapsulate hydrophobic molecules. The reversible phase transfer of the DILs between the aqueous and organic phases was accomplished by simple anion exchange between the hydrophilic Br− anion and the hydrophobic bis(trifluoromethylsulfonyl)amide anion (NTf2−). IL‐Br‐Gn could be used as transporters to shuttle hydrophobic molecules between the organic and aqueous phases efficiently. The present work provides a new kind of transporting materials with potential applications in substance separation, drug delivery, and biomolecule transport.
Tetrathio and Tetraseleno[8]circulenes: Synthesis, Structures, and Properties
Authors: Xiong Xiaodong , Deng Chun‐Lin , Minaev Boris F. , Baryshnikov Gleb V. , Peng Xiao‐Shui , Wong Henry N. C. 
Published: October 2014

AbstractNovel sulfur and selenium‐bridged [8]circulenes were prepared from octabromotetraphenylene. Structures of these compounds were unambiguously confirmed by X‐ray crystallographic analyses. Photophysical and electrochemical investigations of these [8]circulenes suggest their potential applications as electronic materials. The antiaromatic nature of tetrathio[8]circulene and tetraselenium[8]circulene was studied by computational methods, and the NICS computational results reveal that the central eight‐membered ring has highly antiaromatic character.
Enhancing functional expression of heterologous proteins through random substitution of genetic codes in the 5' coding region
Authors: Cheong Dae‐Eun , Ko Kyong‐Cheol , Han Yunjon , Jeon Ho‐Geun , Sung Bong Hyun , Kim Geun‐Joong , Choi Jong Hyun , Song Jae Jun 
Published: October 2014

ABSTRACTRecent studies using heterologous protein expression systems suggest that synonymous codons affect not only the expression but also the properties of the expressed protein. However, practical application of this information is challenging, and to date, efforts to employ bioinformatics tools to design synonymous codon mixes have been only marginally successful. Here, we sought to enhance the functional expression of heterologous protein in Escherichia coli through completely random substitution of the first ten codons with synonymous codons, using a previously isolated exocellulase CelEdx‐SF301 as the model protein. Synonymous codon variants were generated by PCR using forward primers with mixed nucleotides at the third position in each codon and a conventional reverse primer. The resulting PCR products were inserted upstream of the fluorescent protein mCherry without linkers. After transformation and cultivation, colonies exhibiting red fluorescence were selected, and the activity of SF301‐mCherry fusion proteins was tested. Synonymous codon variant fusion proteins exhibited 35‐ to 530‐fold increases in functional expression compared with wild‐type controls. Unlike results from other reports, we found that the stability of mRNA secondary structure in the 5' untranslated region and codon rarity were not correlated with functional expression level. Our work demonstrates that a completely random mixed of synonymous codons effectively enhances functional expression levels without the need for amino acid substitutions. Biotechnol. Bioeng. 2015;112: 822–826. © 2014 Wiley Periodicals, Inc.
Mineralization initiation of MC3T3‐E1 preosteoblast is suppressed under simulated microgravity condition
Authors: Hu Li‐fang , Li Jing‐bao , Qian Ai‐rong , Wang Fei , Shang Peng 
Published: October 2014

AbstractMicrogravity decreases the differentiation of osteoblast. However, as this process is multistage and complex, the mechanism by which microgravity inhibits osteoblast differentiation is still unclear. We have previously found that 24 h acute treatment of simulated microgravity (SM) with a random positioning machine (RPM) significantly inhibited the differentiation of preosteoblasts and have explored whether osteoblasts show different response to microgravity condition at other stages, such as the mineralizing‐stage. Murine MC3T3‐E1 preosteoblasts induced for osteogenic differentiation for seven days were cultured either under normal gravity or SM conditions for 24 h. SM treatment significantly suppressed mineralized nodule formation. Alkaline phosphatase (ALP) activity was dramatically decreased, and the expression of ALP gene was downregulated. Expression of well‐known markers and regulators for osteoblasts differentiation, including osteocalcin (OC), type I collagen α1 (Col Iα1), dentin matrix protein 1 (DMP1) and runt‐related transcription factor 2 (Runx2), were downregulated. Western blot analysis showed that the phosphorylated extracellular signal‐regulated kinase (p‐ERK) level was lower under SM condition. Thus, the initiation of osteoblast mineralization is suppressed by SM condition, and the suppression may be through the regulation of ALP activity and the osteogenic gene expression. ERK signaling might be involved in this process. These results are relevant to the decrease of osteoblast maturation and bone formation under microgravity condition.
Highly Efficient and Magnetically Recoverable Niobium Nanocatalyst for the Multicomponent Biginelli Reaction
Authors: Lima Carolina G. S. , Silva Sandrina , Gonçalves Ricardo H. , Leite Edson R. , Schwab Ricardo S. , Corrêa Arlene G. , Paixão Márcio W. 
Published: October 2014

AbstractA new magnetically recoverable nanocatalyst was prepared by coating magnetite with niobium oxide (Fe3O4@Nb2O5) by using a simple wet impregnation method. The Fe3O4@Nb2O5 nanocatalyst was fully characterized, and its catalytic activity was evaluated by using the one‐pot, three‐component Biginelli reaction, with the aim to synthesize 1,4‐dihydropyrimidinones, a class of compounds with diverse pharmacological properties. The developed protocol was applied to a wide range of aliphatic and aromatic substrates, and structurally diverse products were obtained in excellent yields. Compared with copper and nickel nanocatalysts, the Fe3O4@Nb2O5 nanocatalyst demonstrated superior catalytic activity at a remarkably low catalyst loading (0.1 mol %). This niobium nanocatalyst could be easily separated from the reaction mixture with an external magnet and was reused several times without any loss of its catalytic activity. Moreover, although the Biginelli reaction is a century‐old reaction, its mechanism is still a controversial subject, and our investigation provided an insight into the reaction mechanism.