bluuebunny/crossref_metadata_2025_split huggingface dataset:
Perturbation electric fields and disturbance currents investigated during the 25 September 1998 great storm
Authors: Horvath Ildiko , Lovell Brian C. 
Published: September 2014

AbstractThis study investigates the ionosphere's response to the 25 September 1998 great storm and utilizes multi‐instrument observations covering the Australian (140°E; geographic) and Indian (75°E) longitude sectors. Results show the domination of eastward (westward) electrojet at 140°E (75°E). Its causative net eastward (westward) perturbation electric (E) field drove the forward (reverse) plasma fountain, caused the presence (absence) of the equatorial ionization anomaly (EIA). These strong longitudinal differences were due to a combination of various LT‐dependent, E field‐driven, and competing mechanisms. Perturbation E fields are identified as prompt penetration E field (PPEF) and disturbance dynamo E field (DDEF). Due to the later (earlier) local time at 140°E (75°E), the undershielding PPEF was eastward (westward) directed early in the main phase. A series of periodic substorms occurred during the recovery phase. The substorm‐related eastward PPEFs became overpowered by westward DDEFs over India but remained dominant in the Australian sector. Thus, eastward PPEFs (westward DDEFs) dominated at 140°E (75°E). At 140°E these eastward PPEFs exhibited a strong positive correlation with the variations of both the cross polar cap potential drop and the asymmetric ring current, significantly increased the net equatorial upward E × B drift and thus caused EIA development with plasma bubbles scintillating GPS signals. Based on the strong and independent correlation of these asymmetric ring current events with both the EIA development and the scintillation activity, we propose that the ASY‐H index could provide a natural tool for modeling EIA development and scintillation episodes during severe storms characterized by periodic substorm‐related eastward PPEFs.
Average QLg, QSn, and observation of Lg blockage in the Continental Margin of Nova Scotia
Authors: Mousavi S. Mostafa , Cramer Chris H. , Langston Charles A. 
Published: September 2014

AbstractThe term “Lg blockage” refers to the sudden disappearance of the Lg phase along a particular propagation path which is commonly seen at continental‐oceanic transition zones. In this paper we present observational evidence of Lg blockage across the continental margin of Nova Scotia in eastern Canada. Regional Lg and Sn spectra from 91 events with epicentral distances between 100 and 1200 km and magnitudes between 2.5 and 4.7 are inverted simultaneously for the source spectrum, site amplification, and average attenuation. The vertical displacement spectra were estimated between 0.9 and 10.75 Hz. The assumptions include a fixed frequency‐independent geometric spreading rate for Lg and a frequency‐dependent spreading model for the Sn. Estimates for the apparent regional attenuations are QLg (f) = 615(±25) f0.35(±0.04) and QSn (f) = 404(±23) f0.45(±0.03). Results from this study provide an accurate parameterization of observed amplitude spectra and are valuable for representing wave propagation in the region. Based on the observation of a strong trade‐off between Sn and Lg amplitudes which have different attenuation characteristics, we conclude any attenuation study based on measuring amplitude of a package of several different phases, without taking into consideration the propagation characteristics of individual waveforms at the region of study, may bias the estimation of average regional Q.
Sulfoxylic and Thiosulfurous Acids and their Dialkoxy Derivatives
Authors: Makarov Sergei V. , Makarova Anna S. , Silaghi‐Dumitrescu Radu 
Published: September 2014

AbstractBeing potent reductants, sulfoxylic acid S(OH)2and its salts (sulfoxylates) are intermediates in many reactions of important industrial chemicals, such as sodium hydroxymethanesulfinate (rongalite) and thiourea dioxide. Sulfoxylates contain the ‐O‐S‐O‐ moiety, which is isoelectronic to trioxides, ‐O‐O‐O‐. However, the apparent structural and valence electron count similarity may be contrasted to significant differences in reactivity.Thiosulfurous acid H2S2O2is a primary product of reaction between hydrogen sulfide and sulfur dioxide. Despite the central role of the S‐S bond in organic, inorganic and biological chemistry, thiosulfurous acid remains one of the least studied sulfur acids together with its one sulfur counterpart–sulfoxylic acid. Here we present the first special review describing the structure, stability and reactivity of these acids and their anions.Organic derivatives of sulfoxylic and thiosulfurous acids are much more studied than the acids themselves. In this review, organic derivatives of sulfoxylic and thiosulfurous acids (dialkoxy sulfoxylates (R‐O‐S‐O‐R) and dialkoxy disulfides (R‐O‐S‐S‐O‐R), which are isoelectronic to organic trioxides and tetroxides), as well as organic trisulfanes R‐S‐S‐S‐R and tetrasulfanes R‐S‐S‐S‐S‐R, respectively, are also briefly discussed.
The characteristic and kinetic studies on the enantioselective hydrolysis of (R, S)‐α‐ethyl‐2‐oxo‐1‐pyrrolidine acetic acid ethyl ester catalyzed by Tsukamurella tyrosinosolvens E105‐derived hydrolase
Authors: Huang Jin , Yan Ren , Shi Haifang , Wang Pu , He Junyao 
Published: September 2014

ABSTRACTAs a key chiral intermediate of Levetiracetam, (S)‐α‐ethyl‐2‐oxo‐1‐pyrrolidine acetic acid can be produced by ester hydrolase‐catalyzed hydrolysis of (R, S)‐α‐ethyl‐2‐oxo‐1‐pyrrolidine acetic acid ethyl ester. In this paper, the characteristics and kinetics of such hydrolysis were investigated using ester hydrolase derived from soil bacterium Tsukamurella tyrosinosolvens E105. Effects of different parameters were systematically investigated to reveal the primary factors that determine the performance of the enantioselective hydrolysis. The optimal reaction conditions were found to be as follows: temperature, 30 °C; pH, 7.0; potassium phosphate buffer, 0.5 mol/L; and 9.2 mmol/L of substrate. Under the optimum conditions, a substrate inhibition kinetic model based on Michaelis–Menten was proposed and verified with experimental data. Moreover, the obtained kinetic constants were Km = 6.73 mmol/L, Vmax = 18.9 × 10−3 mmol/L/min and Ksi = 23.7 mmol/L. This model can be used to predict the ester hydrolase‐catalyzed hydrolysis of (R, S)‐α‐ethyl‐2‐oxo‐1‐pyrrolidine acetic acid ethyl ester and will be advantageous to the industrial application of this process. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
Brain‐Derived Neurotrofic Factor and its Receptor TrkB are Present, but Segregated, Within Mature Cutaneous Pacinian Corpuscles of Macaca fascicularis
Authors: Cabo R. , Alonso P. , José I. San , Vázquez G. , Pastor J.F. , Germanà A. , Vega J.A. , García‐Suárez O. 
Published: September 2014

ABSTRACTSome mechanoreceptors in mammals depend totally or in part on the neurotrophins brain‐derived neurotrophic factor (BDNF) and neurotrophin‐4 (NT‐4), and their receptor TrkB, for development and maintenance. These actions are presumably exerced regulating the survival of discrete sensory neurons in the dorsal root ganglia which form mechanoreceptors at the periphery. In addition, the cells forming the mechanoreceptors also express both neurotrophins and their receptors although large differences have been described among species. Pacinian corpuscles are rapidly adapting low‐threshold mechanoreceptors whose dependence from neurotrophins is not known. In the present study, we analyzed expression of TrkB and their ligands BDNF and NT‐4 in the cutaneous Pacinian corpuscles of Macaca fascicularis using immunohistochemistry and fluorescent microscopy. TrkB immunoreactivity was found in Pacinian corpuscles where it co‐localized with neuron‐specific enolase, and occasionally with S100 protein, thus suggesting that TrkB expression is primarily into axons but also in the lamellar cells and even in the outer core. On the other hand, BDNF immunoreactivity was found the inner core cells where it co‐localized with S100 protein but also in the innermost layers of the outer core; NT‐4 immunostaining was not detected. These results describe for the first time the expression and distribution of a full neurotrophin system in the axon‐inner core complex of mature Pacinian corpuscles. The data support previous findings demonstrating large differences in the expression of BDNF‐TrkB in mammalian mechanoreceptors, and also suggest the existence of a retrograde trophic signaling mechanism to maintain morphological and functional integrity of sensory neurons supplying Pacinian corpuscles. Anat Rec, 298:624–629, 2015. © 2014 Wiley Periodicals, Inc.
Oligostilbenoids from the Heartwood of N. Heimii: Role of Non‐Covalent Association in their Biogenesis
Authors: Bayach Imene , Manshoor Nurhuda , Sancho‐García Juan Carlo , Choudhary Muhammad Iqbal , Trouillas Patrick , Weber Jean‐Frédéric Faizal 
Published: September 2014

AbstractFour new oligostilbenes, including one dimer and three tetramers of resveratrol, that is, heimiols B–E (1–4) were isolated from the heartwood of Neobalanocarpus heimii (Dipterocarpaceae), together with thirteen known resveratrol oligomers (5–17). Examination of the structural diversity of the isolated oligostilbenes led to hypothesis of their biogenetic origin through a small number of versatile chemical pathways. These hypotheses are strongly supported by computational calculations (based on the density functional theory, DFT) that were performed to rationalize conformational re‐arrangements and thus provide insights into the mechanism of oligostilbenoid biosynthesis. Non‐covalent complexes are believed to drive the regio‐ and stereoselectivity of the oligomerization reactions.
Modification of Nucleic Acids by Azobenzene Derivatives and Their Applications in Biotechnology and Nanotechnology
Authors: Li Jing , Wang Xingyu , Liang Xingguo 
Published: September 2014

AbstractAzobenzene has been widely used as a photoregulator due to its reversible photoisomerization, large structural change between E and Z isomers, high photoisomerization yield, and high chemical stability. On the other hand, some azobenzene derivatives can be used as universal quenchers for many fluorophores. Nucleic acid is a good candidate to be modified because it is not only the template of gene expression but also widely used for building well‐organized nanostructures and nanodevices. Because the size and polarity distribution of the azobenzene molecule is similar to a nucleobase pair, the introduction of azobenzene into nucleic acids has been shown to be an ingenious molecular design for constructing light‐switching biosystems or light‐driven nanomachines. Here we review recent advances in azobenzene‐modified nucleic acids and their applications for artificial regulation of gene expression and enzymatic reactions, construction of photoresponsive nanostructures and nanodevices, molecular beacons, as well as obtaining structural information using the introduced azobenzene as an internal probe. In particular, nucleic acids bearing multiple azobenzenes can be used as a novel artificial nanomaterial with merits of high sequence specificity, regular duplex structure, and high photoregulation efficiency. The combination of functional groups with biomolecules may further advance the development of chemical biotechnology and biomolecular engineering.
Efficient Intramolecular Energy Transfer between Two Fluorophores in a Bis‐Branched [3]Rotaxane
Authors: Yao Jian , Li Hong , Xu Ya‐Nan , Wang Qiao‐Chun , Qu Da‐Hui 
Published: September 2014

AbstractA bis‐branched [3]rotaxane, with two [2]rotaxane arms separated by an oligo(para‐phenylenevinylene) (OPV) fluorophore, was designed and investigated. Each [2]rotaxane arm employed a difluoroboradiaza‐s‐indacene (BODIPY) dye‐functionalized dibenzo[24]crown‐8 macrocycle interlocked onto a dibenzylammonium in the rod part. The chemical structure of the [3]rotaxane was confirmed and characterized by 1H and 13C NMR spectroscopy and high‐resolution ESI mass spectrometry. The photophysical properties of [3]rotaxane and its reference systems were investigated through UV/Vis absorption, fluorescence, and time‐resolved fluorescence spectroscopy. An efficient energy‐transfer process in [3]rotaxane occurred from the OPV donor to the BODIPY acceptor because of the large overlap between the absorption spectrum of the BODIPY moiety and the emission spectrum of the OPV fluorophore; this shows the important potential of this system for designing functional molecular systems.
o‐Fluorination of Aromatic Azides Yields Improved Azido‐Based Fluorescent Probes for Hydrogen Sulfide: Synthesis, Spectra, and Bioimaging
Authors: Wei Chao , Wang Runyu , Wei Lv , Cheng Longhuai , Li Zhifei , Xi Zhen , Yi Long 
Published: September 2014

AbstractHydrogen sulfide (H2S) is an endogenously produced gaseous signaling molecule with multiple biological functions. To visualize the endogenous in situ production of H2S in real time, new coumarin‐ and boron‐dipyrromethene‐based fluorescent turn‐on probes were developed for fast sensing of H2S in aqueous buffer and in living cells. Introduction of a fluoro group in the ortho position of the aromatic azide can lead to a greater than twofold increase in the rate of reaction with H2S. On the basis of o‐fluorinated aromatic azides, fluorescent probes with high sensitivity and selectivity toward H2S over other biologically relevant species were designed and synthesized. The probes can be used to in situ to visualize exogenous H2S and D‐cysteine‐dependent endogenously produced H2S in living cells, which makes them promising tools for potential applications in H2S biology.
High‐level secretory expression and purification of unhydroxylated human collagen α1(III) chain in Pichia pastoris GS115
Authors: Li Linbo , Fan Daidi , Ma Xiaoxuan , Deng Jianjun , He Jing 
Published: September 2014

AbstractRecombinant collagen and gelatin have been applied in biomedical materials field because of products from genetically engineered microorganisms with improved safety, traceability, reproducibility, and homogeneous quality. To obtain high‐level secretory expression of single‐chain full‐length human collagen α1(III) chain (COL3A1) without the N and C telopeptides, the cDNA coding for the human COL3A1 gene was cloned into the secretory expression vector pPIC9K and integrated into Pichia pastoris GS115. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and Western blotting analysis of culture supernatant from the recombinant methylotrophic yeast suggested that the unhydroxylated recombinant human COL3A1 (rhCOL3A1) was secreted into the culture medium, and exhibited an apparent molecular mass of approximately 130 kDa, which is 1.4 times higher than the theoretical one. Finally, the unhydroxylated rhCOL3A1 was purified to greater than 90% purity using a four‐step approach. In addition, methylthiazolydiphenyl‐tetrazolium bromide experiments indicated that low concentration of rhCOL3A1 could promote Baby hamster kidney cell (BHK21) proliferation effectively. The production and purification of rhCOL3A1 described in this study offer a new method for obtaining high level of rhCOL3A1 in relatively pure form, which is suitable for biomedical materials application.
TGFβ and Wnt in Cardiac Outflow Tract Defects in Offspring of Diabetic Pregnancies
Authors: Zhao Zhiyong 
Published: September 2014

BACKGROUNDDiabetes mellitus in pregnancy causes defects in infant heart, including the outflow tracts (OFTs). Development of the aorta and pulmonary artery, which are derived from the common OFT in the embryo, is regulated by the transforming growth factor β (TGFβ) and Wnt families, and can be perturbed by hyperglycemia‐generated intracellular stress conditions. However, the underlying cellular and molecular mechanisms remain to be delineated.METHODSFemale mice were induced diabetic with streptozotocin. Embryonic and fetal OFTs were examined morphologically and histologically. Cell proliferation was assessed using 5’‐bromo‐2’‐deoxyuridine incorporation assay. Oxidative and endoplasmic reticulum (ER) stress markers and TGFβ factors were detected using immunohistochemistry. The expression of genes in the Wnt‐signaling system was assessed using real‐time reverse transcription polymerase chain reaction array. The role of activin‐A in cell proliferation was addressed by treating embryos cultured in high glucose with activin‐A.RESULTSMaternal diabetes caused complex abnormalities in the OFTs, including aortic and pulmonary stenosis and persistent truncus arteriosus. The development of the endocardial cushions was suppressed, manifested with insufficient cellularization of the tissues. Cell proliferation was significantly decreased under oxidative and ER stress conditions. The expression of genes in the Wnt signaling was significantly altered. Activin‐A and Smad3 were found to be expressed in the OFT. Treatment with activin‐A rescued cell proliferation in the endocardial cushions.CONCLUSIONSMaternal diabetes generates oxidative and ER stress conditions, suppresses TGFβ and Wnt signaling, inhibits cell proliferation and cellularization of the endocardial cushions, leading to OFT septal defects. Activin‐A plays a role in hyperglycemia‐suppressed proliferation of the endocardial cells
Synthesis of Novel Phosphonic‐Type Activity‐Based Probes for Neutrophil Serine Proteases and Their Application in Spleen Lysates of Different Organisms
Authors: Grzywa Renata , Burchacka Ewa , Łęcka Maria , Winiarski Łukasz , Walczak Maciej , Łupicka‐Słowik Agnieszka , Wysocka Magdalena , Burster Timo , Bobrek Kamila , Csencsits‐Smith Keri , Lesner Adam , Sieńczyk Marcin 
Published: September 2014

AbstractNeutrophils are a type of granulocyte important in the “first line of defense” of the innate immune system. Upon activation, they facilitate the destruction of invading microorganisms by the production of superoxide radicals, as well as the release of the enzymatic contents of their lysozymes. These enzymes include specific serine proteases: cathepsin G, neutrophil elastase, proteinase 3, as well as the recently discovered neutrophil serine protease 4 (NSP4). Under normal conditions, the proteolytic activity of neutrophil proteases is tightly regulated by endogenous serpins; however, this mechanism can be subverted during tissue stress, thereby resulting in the uncontrolled activity of serine proteases, which induce chronic inflammation and subsequent pathology. Herein, we describe the development of low‐molecular‐weight activity‐based probes that specifically target the active sites of neutrophil proteases.
Evaluation of the Calmodulin‐SOX9 Interaction by “Magnetic Fishing” Coupled to Mass Spectrometry
Authors: McFadden Meghan J. , Hryciw Todd , Brown Arthur , Junop Murray S. , Brennan John D. 
Published: September 2014

AbstractDisruption of calmodulin (CaM)‐based protein interactions has been touted as a potential means for modulating several disease pathways. Among these is SOX9, which is a DNA binding protein that is involved in chrondrocyte differentiation and regulation of the hormones that control sexual development. In this work, we employed a “magnetic fishing”/mass spectrometry assay in conjunction with intrinsic fluorescence to examine the interaction of CaM with the CaM‐binding domain of SOX9 (SOX‐CAL), and to assess the modulation of this interaction by known anti‐CaM compounds. Our data show that there is a high affinity interaction between CaM and SOX‐CAL (27±9 nM), and that SOX‐CAL bound to the same location as the well‐known CaM antagonist melittin; unexpectedly, we also found that addition of CaM‐binding small molecules initially produced increased SOX‐CAL binding, indicative of binding to both the well‐known high‐affinity CaM binding site and a second, lower‐affinity binding site.
Oncogenic nature of a novel mutant AATF and its interactome existing within human cancer cells
Authors: Sharma Shaveta , Kaul Deepak , Arora Mansi , Malik Deepti 
Published: September 2014

AbstractSince apoptosis presents a natural defense in cancer development, the anti‐apoptotic factor AATF/Che‐1 has emerged as a crucial ‘Epigenomic‐Switch’. We have tried to understand the double‐edged nature of AATF, showing for the first time the conspicuous existence of an aberrant AATF/Che‐1 transcriptome encoding for 23 kDa mutant AATF protein, which evolves its unique interactome within human cancer cells derived from different tissue origins. This mutant AATF along with its interactome consisting of SP1, DNMT3B and Par‐4 ensures cancer cell DNA methylation required for down‐regulation of tumor suppressor genes. Hence, the proposed mutant AATF interactome‐based pathway can have the inherent ability to ensure human cells become and remain cancerous.
Formic Acid Dehydrogenation Catalysed by Tris(TPPTS) Ruthenium Species: Mechanism of the Initial “Fast” Cycle
Authors: Thevenon Arnaud , Frost‐Pennington Ewan , Weijia Gan , Dalebrook Andrew F. , Laurenczy Gábor 
Published: September 2014

AbstractWater‐soluble ruthenium m‐triphenylphosphinetrisulfonate (TPPTS) complexes are excellent catalysts for formic acid dehydrogenation. Interestingly, the choice of metal catalyst precursor has a direct influence on initial activities. The reaction with hexaaquaruthenium(II) tosylate directly yields bisphosphine complexes in the presence of TPPTS and formic acid, whereas trisphosphine adducts are involved if the reaction starts with ruthenium(III) chloride. We present the results of a series of manometric and spectroscopic experiments that reveal the true nature of these highly active species, and subsequently propose a rational “fast” cycle mechanism explaining this peculiar activity profile.
Grooves of Bundled Single‐Walled Carbon Nanotubes Dramatically Enhance the Activity of the Oxygen Reduction Reaction
Authors: Fujigaya Tsuyohiko , Morita Junichi , Nakashima Naotoshi 
Published: September 2014

AbstractNitrogen‐doped graphitic structures (N‐GSs) are promising and cheap catalyst candidates for the oxygen reduction reaction (ORR). In this paper, we describe, first, the synthesis of single‐walled carbon nanotubes (SWNTs) coated by a N‐GS (SWNT/N‐GS) and, second, the dramatic enhancement in the activity of the ORR by using this catalyst relative to that observed for the analogue composite composed of multiwalled carbon nanotubes (MWNTs) coated by a N‐GS (i.e., MWNT/N‐GS). Scanning electron microscopy and gas‐adsorption experiments revealed that the SWNT/N‐GS formed a bundled structure and that superior gas adsorption behavior originated from this groove structure. It is assumed that the grooves of the bundled SWNT/N‐GS dramatically enhance the activity of the ORR owing to superior O2 adsorption on the grooves.
Polyvinyl Alcohol–Borax Slime as Promising Polyelectrolyte for High‐Performance, Easy‐to‐Make Electrochromic Devices
Authors: Alesanco Yolanda , Palenzuela Jesús , Viñuales Ana , Cabañero Germán , Grande Hans J. , Odriozola Ibon 
Published: September 2014

AbstractA novel slime‐type electrochromic system based on polyvinyl alcohol (PVA) and borax, in combination with a viologen and a redox pair has been developed. On top of overcoming the limitations of both liquid electrolytes, such as the risk of leakage and difficulty of assembly and of solid electrolytes, such as limited transparency and slow response time, this easy‐to‐make slime electrochromic system offers an excellent wettability and transparency and achieves high‐performance in terms of optical contrast (>65 % at 550 nm), switching time (<5 s as estimated for 90 % of the total transmittance change at 550 nm) and cyclability (8 000–10 000). For the electrochromic devices shown here, the CIELAB 1976 color space coordinates at the “on” state were L*=7.12, a*=18.08, and b*=−21.02, corresponding to a purple color. The color efficiencies were 75.5 cm2 C−1 and 149.3 cm2 C−1 for coloration and bleaching processes respectively.