bluuebunny/crossref_metadata_2025_split huggingface dataset:
50 kHz bottom backscattering measurements from two types of artificially roughened sandy bottoms
Authors: Son Su-Uk , Cho Sungho , Choi Jee Woong 
Published: June 2016

Abstract
Laboratory measurements of 50 kHz bottom backscattering strengths as a function of grazing angle were performed on the sandy bottom of a water tank; two types of bottom roughnesses, a relatively smooth interface and a rough interface, were created on the bottom surface. The roughness profiles of the two interface types were measured directly using an ultrasound arrival time difference of 5 MHz and then were Fourier transformed to obtain the roughness power spectra. The measured backscattering strengths increased from −29 to 0 dB with increasing grazing angle from 35 to 86°, which were compared to theoretical backscattering model predictions. The comparison results implied that bottom roughness is a key factor in accurately predicting bottom scattering for a sandy bottom.
Early Evaluation of Relative Changes in Tumor Stiffness by Shear Wave Elastography Predicts the Response to Neoadjuvant Chemotherapy in Patients With Breast Cancer
Authors: Jing Hui , Cheng Wen , Li Zi-Yao , Ying Liu , Wang Qiu-Cheng , Wu Tong , Tian Jia-Wei 
Published: June 2016

ObjectivesNeoadjuvant chemotherapy plays an important role in comprehensive therapy for breast cancer, but response prediction is imperfect. Shear wave elastography (SWE) is a novel technique that can quantitatively evaluate tissue stiffness. In this study, we sought to investigate the application value of SWE for early prediction of the response to neoadjuvant chemotherapy in patients with breast cancer.MethodsWe prospectively evaluated tumor stiffness in 62 patients with breast cancer using SWE, which was performed at baseline and after the second cycle of neoadjuvant chemotherapy. After chemotherapy, all of the patients underwent surgery. We investigated the correlations between the relative changes in tumor stiffness (Δ stiffness) after 2 cycles of chemotherapy and the pathologic response to the therapy.ResultsCompared with baseline values, tumor stiffness after 2 cycles of neoadjuvant chemotherapy was significantly decreased in responders (P < .001) but not in nonresponders (P = .172). The Δstiffness was significantly higher in responders (−42.194%) than in nonresponders (−23.593%; P = .001). As determined at either the baseline or after the second cycle of chemotherapy, tumor stiffness was significantly lower in responders than in nonresponders (P = .033 and .009, respectively). The Δ stiffness threshold for distinguishing between responders and nonresponders was −36.1% (72.92% sensitivity and 85.71% specificity). Furthermore, correlating Δ stiffness with clinical and pathologic characteristics, we found that estrogen and progesterone receptor expression showed statistically significant correlations with Δ stiffness (estrogen receptor, P = .008; progesterone receptor, P = .023).ConclusionsEarly evaluation of relative changes in tumor stiffness using SWE could effectively predict the response to neoadjuvant chemotherapy in patients with breast cancer and might indicate better therapeutic strategies on a timelier basis.
Sonographic‐Pathologic Correlation for Punctate Echogenic Reflectors in Papillary Thyroid Carcinoma
Authors: Tahvildari Ali M. , Pan Lorraine , Kong Christina S. , Desser Terry 
Published: June 2016

ObjectivesIt is commonly held that punctate nonshadowing echogenic foci on sonography, often termed microcalcifications, represent psammoma bodies. We aimed to determine the validity of this supposition by correlating the presence of punctate echogenic foci on sonography with their presence at histopathologic examination.MethodsWe examined 51 nodules (surgically proven papillary thyroid carcinoma) by sonography and histopathologic examination. On the latter, nodules were examined for evidence of psammomatous calcifications, dystrophic calcifications, and colloid. Two subspecialty‐trained radiologists with 2 and 25 years of experience in sonography, respectively, reviewed the sonograms for the presence and distribution of punctate echogenic foci.ResultsAll nodules contained colloid at histologic examination. Twenty of the papillary carcinomas lacked any calcification at pathologic examination. In the remaining 31 nodules with calcifications, 13 had psammomatous calcifications only; 6 had both coarse and psammomatous calcifications; and 12 had only coarse calcifications. The presence of punctate echogenic foci on sonography was 74% sensitive, was 46% to 53% specific, and had a positive predictive value of only 45% to 48% for the presence of psammomatous calcifications. The computed 2‐tailed P value indicated that the punctate echogenic foci‐to‐psammoma body correlation was not statistically significant.ConclusionsThe sonographic signature commonly referred to as “microcalcifications” may represent a variety of entities, including psammomatous calcifications, dystrophic calcifications, and eosinophilic colloid; for this reason, “punctate echogenic foci” would be a more accurate term.
A new perspective on global mean sea level (GMSL) acceleration
Authors: Watson Phil J. 
Published: June 2016

AbstractThe vast body of contemporary climate change science is largely underpinned by the premise of a measured acceleration from anthropogenic forcings evident in key climate change proxies—greenhouse gas emissions, temperature, and mean sea level. By virtue, over recent years, the issue of whether or not there is a measurable acceleration in global mean sea level has resulted in fierce, widespread professional, social, and political debate. Attempts to measure acceleration in global mean sea level (GMSL) have often used comparatively crude analysis techniques providing little temporal instruction on these key questions. This work proposes improved techniques to measure real‐time velocity and acceleration based on five GMSL reconstructions spanning the time frame from 1807 to 2014 with substantially improved temporal resolution. While this analysis highlights key differences between the respective reconstructions, there is now more robust, convincing evidence of recent acceleration in the trend of GMSL.
A high‐resolution record of Greenland mass balance
Authors: McMillan Malcolm , Leeson Amber , Shepherd Andrew , Briggs Kate , Armitage Thomas W. K. , Hogg Anna , Kuipers Munneke Peter , van den Broeke Michiel , Noël Brice , van de Berg Willem Jan , Ligtenberg Stefan , Horwath Martin , Groh Andreas , Muir Alan , Gilbert Lin 
Published: June 2016

AbstractWe map recent Greenland Ice Sheet elevation change at high spatial (5 km) and temporal (monthly) resolution using CryoSat‐2 altimetry. After correcting for the impact of changing snowpack properties associated with unprecedented surface melting in 2012, we find good agreement (3 cm/yr bias) with airborne measurements. With the aid of regional climate and firn modeling, we compute high spatial and temporal resolution records of Greenland mass evolution, which correlate (R = 0.96) with monthly satellite gravimetry and reveal glacier dynamic imbalance. During 2011–2014, Greenland mass loss averaged 269 ± 51 Gt/yr. Atmospherically driven losses were widespread, with surface melt variability driving large fluctuations in the annual mass deficit. Terminus regions of five dynamically thinning glaciers, which constitute less than 1% of Greenland's area, contributed more than 12% of the net ice loss. This high‐resolution record demonstrates that mass deficits extending over small spatial and temporal scales have made a relatively large contribution to recent ice sheet imbalance.
Magnetic Nanoparticles‐Supported Chiral Catalyst with an Imidazolium Ionic Moiety: An Efficient and Recyclable Catalyst for Asymmetric Michael and Aldol Reactions
Authors: Ying Anguo , Liu Shuo , Li Zhifeng , Chen Gang , Yang Jianguo , Yan Hua , Xu Songlin 
Published: June 2016

AbstractA magnetic nanoparticles‐supported chiral aminocyclohexane in combination with sulfamide, which was modified by an imidazolium ionic moiety, was prepared and characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), thermal gravimetric (TG) analysis and elementary analysis. The catalyst was successfully applied not only in the enantioselective Michael addition but also in the asymmetric aldol condensation to afford good to excellent yields (70–94%) and satisfactory stereoselectivity (ee: 92–100%, dr: 91:9–99:1).The role of the ionic moiety was verified by comparison of the catalyst with an ionic moiety‐free counterpart. The heterogeneous catalyst was easily separated and recovered using external magnetic force and can be used for up to five times without obvious loss in its catalytic activity.magnified image
Recyclable Enantioselective Catalysts Based on Copper(II) Complexes of 2‐(Pyridine‐2‐yl)imidazolidine‐4‐thione: Their Application in Asymmetric Henry Reactions
Authors: Nováková Gabriela , Drabina Pavel , Frumarová Božena , Sedlák Miloš 
Published: June 2016

AbstractThis paper describes the preparation of enantioselective catalysts based on derivatives of imidazolidine‐4‐thione and their subsequent anchoring by means of a sulfur atom on a polymeric carrier. First, we verified the catalytic activity and enantioselectivity in the Henry reaction of the homogeneous variants of the catalysts, i.e., the copper(II) complexes of 2‐(pyridine‐2‐yl)imidazolidine‐4‐thiones and 4‐benzylsufanyl‐2‐(pyridine‐2‐yl)imidazolines themselves. It was found that these catalysts exhibit high enantioselectivity (up to 98% ee). Subsequently, the imidazolidine‐4‐thione catalysts were immobilized by anchoring to polymeric carriers based on a copolymer of styrene and 4‐vinylbenzyl chloride. These heterogeneous catalysts were analogously tested with regard to their catalytic activity and enantioselectivity in the Henry reaction, and moreover, the possibility of their separation and reuse was studied. It was found that all the prepared immobilized catalysts are highly enantioselective (up to 97% ee). Their recycling ability was tested in Henry reaction of 2‐methoxybenzaldehyde with nitromethane. It was found that they can be recycled more than ten times without any decrease of their enantioselectivity. Therefore, they present a better means of catalysis than the original copper(II) complexes of imidazolidine‐4‐ones from both economic as well as ecological points of view. Thus, such immobilized catalysts exhibit high application potential for the asymmetric Henry reaction.magnified image
Neue Ansätze für die Synthese von Metallcarbenen
Authors: Jia Minqiang , Ma Shengming 
Published: June 2016

AbstractMetallcarbene sind vielseitige Verbindungen, deren Reaktivität sowohl durch das Metall als auch den Liganden gesteuert werden kann. Zur Synthese von Metallcarbenen nutzt man im Allgemeinen die Stickstoff‐Eliminierung von Diazoverbindungen, die allerdings häufig instabil, explosiv und toxisch sind, was ihren Einsatz in großskaligen Synthesen einschränkt. Demzufolge gibt es eine intensive Suche nach nachhaltigen und ungefährlichen Ersatzsubstraten für die zuverlässige Herstellung von Metallcarbenen. In diesem Aufsatz fassen wir die wichtigsten Fortschritte bei der Erzeugung, katalytischen Reaktionen und der Selektivitätskontrolle von Metallcarbenen zusammen, die nicht aus Diazoverbindungen gebildet wurden.
Gold(I)‐Catalyzed N‐Desulfonylative Amination versus N‐to‐O 1,5‐Sulfonyl Migration: A Versatile Approach to 1‐Azabicycloalkanes
Authors: Miaskiewicz Solène , Gaillard Boris , Kern Nicolas , Weibel Jean‐Marc , Pale Patrick , Blanc Aurélien 
Published: June 2016

AbstractValuable 1‐azabicycloalkane derivatives have been synthesized through a novel gold(I)‐catalyzed desulfonylative cyclization strategy. An ammoniumation reaction of ynones substituted at the 1‐position with an N‐sulfonyl azacycle took place in the presence of a gold cation by intramolecular cyclization of the disubstituted sulfonamide moiety onto the triple bond. Depending on the size of the heterocyclic ring and substitution of the substrates, two unprecedented forms of nucleophilic attack on the sulfonyl group were exploited, that is, a N‐desulfonylation in the presence of an external protic O nucleophile (37–87 %, 10 examples) and a unique N‐to‐O 1,5‐sulfonyl migration (60–98 %, 9 examples).
The role of carbonaceous aerosols on short‐term variations of precipitation over North Africa
Authors: Yoon Jin‐Ho , Rasch Philip J. , Wang Hailong , Vinoj V. , Ganguly Dilip 
Published: June 2016

AbstractSubtropical North Africa has been subject to extensive droughts in the late 20th century, linked to changes in the sea surface temperature (SST). However, climate models forced by observed SSTs cannot reproduce the magnitude of the observed rainfall reduction. Here, we propose aerosol indirect effects (AIE) as an important positive feedback mechanism. Model results are presented using two sets of sensitivity experiments designed to distinguish the role of aerosol direct/semi‐direct and indirect effects on regional precipitation. Changes in cloud properties due to the presence of carbonaceous aerosols are proposed as a key mechanism to explain the reduced rainfall over subtropical North Africa.
Expression of a gap junction protein, connexin43, in a large panel of human gliomas: new insights
Authors: Crespin Sophie , Fromont Gaëlle , Wager Michel , Levillain Pierre , Cronier Laurent , Monvoisin Arnaud , Defamie Norah , Mesnil Marc 
Published: June 2016

AbstractPrecise diagnosis of low and high grades of brain tumors permits determining therapeutical strategies. So far, diagnosis and prognosis of gliomas were based on histological and genetic criteria which need being completed by a panel of molecular markers. Highly distributed in brain, gap junction proteins, connexins, could be considered as markers of glioma progression as previous studies indicated that expression of a connexin type, connexin43 (Cx43), is inversely correlated to tumor grading. However, this assumption was weakened by the low number of glioma samples used. Taking advantage of tissue microarray technique, we pursued this analysis by studying in situ expression of Cx43 on 85 samples (37 grade IV, 18 grade III, 24 grade II, and 6 grades II to III). Our analysis confirmed the global diminution of Cx43 expression in glioblastomas that was observed in previous studies. However, this analysis brought new insights such as the following ones. First, the high number of samples permitted to show that more than 60% of glioblastomas still express Cx43. Second, no gradual decrease in Cx43 expression was observed between grades II and III, but Cx43 appeared to be a marker distinguishing oligodendrocytic and astrocytic grade III tumors. Third, independently from tumor grade, a Cx43 nuclear staining was detected in areas where leukocytes are present. In conclusion, our study emphasizes the importance of in situ immunohistochemical approaches by giving more precise insights in the subcellular localization of Cx43. It also emphasizes the necessity to carry out such analysis on a wide range of samples to circumvent the high glioma heterogeneity.
Rac1 promotes chondrogenesis by regulating STAT3 signaling pathway
Authors: Kim Hyoin , Sonn Jong Kyung 
Published: June 2016

AbstractThe small GTPase protein Rac1 is involved in a wide range of biological processes including cell differentiation. Previously, Rac1 was shown to promote chondrogenesis in micromass cultures of limb mesenchyme. However, the pathways mediating Rac1's role in chondrogenesis are not fully understood. This study aimed to explore the molecular mechanisms by which Rac1 regulates chondrogenic differentiation. Phosphorylation of signal transducer and activator of transcription 3 (STAT3) was increased as chondrogenesis proceeded in micromass cultures of chick wing bud mesenchyme. Inhibition of Rac1 with NSC23766, janus kinase 2 (JAK2) with AG490, or STAT3 with stattic inhibited chondrogenesis and reduced phosphorylation of STAT3. Conversely, overexpression of constitutively active Rac1 (Rac L61) increased phosphorylation of STAT3. Rac L61 expression resulted in increased expression of interleukin 6 (IL‐6), and treatment with IL‐6 increased phosphorylation of STAT3. NSC23766, AG490, and stattic prohibited cell aggregation, whereas expression of Rac L61 increased cell aggregation, which was reduced by stattic treatment. Our studies indicate that Rac1 induces STAT3 activation through expression and action of IL‐6. Overexpression of Rac L61 increased expression of bone morphogenic protein 4 (BMP4). BMP4 promoted chondrogenesis, which was inhibited by K02288, an activin receptor‐like kinase‐2 inhibitor, and increased phosphorylation of p38 MAP kinase. Overexpression of Rac L61 also increased phosphorylation of p38 MAPK, which was reduced by K02288. These results suggest that Rac1 activates STAT3 by expression of IL‐6, which in turn increases expression and activity of BMP4, leading to the promotion of chondrogenesis.
Fork in the road: Are all bifurcations created equal?
Authors: Hira Ravi S. , Dean Larry S. 
Published: June 2016

Key Points

The TRYTON study evaluated routine side branch (SB) stenting with a novel bare metal stent (BMS) designed for true bifurcation lesions (Medina 1,1,1; 1,0,1; 0,1,1) and compared it to a strategy of balloon angioplasty with provisional stenting. It failed to meet the primary endpoint of non‐inferiority in target vessel failure mainly driven by peri‐procedural myocardial infarction (MI) with elevated CK‐MB > 3× the upper limit of normal.
In this substudy, 41% of patients who had a SB diameter > 2.25 mm were evaluated and the new stent was found to be non‐inferior in the primary outcome of target vessel failure with no difference in post‐procedural MI.
This substudy suggests that appropriately sized SB stents with TRYTON may be useful when the SB is >2.25 mm in diameter. However, further studies could evaluate routine use of FFR for SBs; drug eluting versions of the stent as well as stents designed for vessels 2.25 mm in diameter which are frequently felt to be clinically larger when not subjected to core lab analysis.
Zwitterion/Brønsted Acid Mixtures Showing Controlled Lower Critical Solution Temperature‐Type Phase Changes with Water
Authors: Mieno Yuki , Kohno Yuki , Saita Shohei , Ohno Hiroyuki 
Published: June 2016

AbstractA new ammonium‐type zwitterion (ZI), N,N‐dihexyl‐N‐monopentyl‐3‐sulfonyl‐1‐propaneammonium (N665C3S) with adequate hydrophobicity showed reversible and highly temperature‐sensitive lower critical solution temperature (LCST)‐type phase transitions after being mixed with pure water. Generally for such compounds, those with longer alkyl chains were immiscible with water and those with shorter chains were miscible with water, regardless of temperature. A slightly more hydrophobic ZI than N665C3S showed LCST‐type phase behavior with water when it was mixed with equimolar amounts of a Brønsted acid such as trifluoromethanesulfonic acid (HTfO). The phase‐transition temperature of the ZI/Brønsted acid mixed aqueous solution was controllable by water content.
Hydroxyl Radical Generation and DNA Nuclease Activity: A Mechanistic Study Based on a Surface‐Immobilized Copper Thioether Clip‐Phen Derivative
Authors: Romo Adolfo I. B. , Abreu Dieric S. , de F. Paulo Tércio , Carepo Marta S. P. , Sousa Eduardo H. S. , Lemus Luis , Aliaga Carolina , Batista Alzir A. , Nascimento Otaciro R. , Abruña Héctor D. , Diógenes Izaura C. N. 
Published: June 2016

AbstractCoordination compounds of copper have been invoked as major actors in processes involving the reduction of molecular oxygen, mostly with the generation of radical species the assignment for which has, so far, not been fully addressed. In the present work, we have carried out studies in solution and on surfaces to gain insights into the nature of the radical oxygen species (ROS) generated by a copper(II) coordination compound containing a thioether clip‐phen derivative, 1,3‐bis(1,10‐phenanthrolin‐2‐yloxy)‐N‐(4‐(methylthio)benzylidene)propan‐2‐amine (2CP‐Bz‐SMe), enabling its adsorption/immobilization to gold surfaces. Whereas surface plasmon resonance (SPR) and electrochemistry of the adsorbed complex indicated the formation of a dimeric CuI intermediate containing molecular oxygen as a bridging ligand, scanning electrochemical microscopy (SECM) and nuclease assays pointed to the generation of a ROS species. Electron paramagnetic resonance (EPR) data reinforced such conclusions, indicating that radical production was dependent on the amount of oxygen and H2O2, thus pointing to a mechanism involving a Fenton‐like reaction that results in the production of OH..
Evaluation of Fe and Ru Pincer‐Type Complexes as Catalysts for the Racemization of Secondary Benzylic Alcohols
Authors: Bornschein Christoph , Gustafson Karl P. J. , Verho Oscar , Beller Matthias , Bäckvall Jan‐E. 
Published: June 2016

AbstractFe and Ru pincer‐type catalysts are used for the racemization of benzylic alcohols. Racemization with the Fe catalyst was achieved within 30 minutes under mild reaction conditions, with a catalyst loading as low as 2 mol %. This reaction constitutes the first example of an iron‐catalyzed racemization of an alcohol. The efficiency for racemization of the Fe catalyst and its Ru analogue was evaluated for a wide range ofsec‐benzylic alcohols. The commercially available Ru complex proved to be highly robust and even tolerated the presence of water in the reaction mixture.
Oxidative Alkane C−H Alkoxycarbonylation
Authors: Lu Lijun , Shi Renyi , Liu Luyao , Yan Jingwen , Lu Fangling , Lei Aiwen 
Published: June 2016

AbstractDirectly utilizing a chemical feedstock to construct valuable compounds is an attractive prospect in organic synthesis. In particular, the combination of C(sp3)−H activation and oxidative carbonylation involving alkanes and CO gas is a promising and efficient method to synthesize carbonyl derivatives. However, due to the high C−H bond dissociation energy and low polarity of unactivated alkanes, the carbonylation of unactivated C(sp3)−H bonds still remains a great challenge. In this work, we introduce a palladium‐catalyzed radical oxidative alkoxycarbonylation of alkanes to prepare numerous alkyl carboxylates. Various alkanes and alcohols were compatible, generating the desired products in up to 94 % yield. Remarkably, ethane, a constituent of natural gas, could be employed as a substrate under the standard reaction conditions. Preliminary mechanistic studies revealed a probable palladium‐catalyzed radical process.
ChemInform Abstract: A Naturally‐Occurring New Lead‐Based Halocuprate(I).
Authors: Welch Mark D. , Rumsey Michael S. , Kleppe Annette K. 
Published: June 2016

AbstractPb2Cu(OH)2I3, a new type of a halocuprate(I) is discovered as a natural mineral in a rock specimen from the Cu—Zn—Pb ore deposit in NSW, Australia.
ChemInform Abstract: Phase Transition, Conformational Exchange, and Nonlinear Optical Third Harmonic Generation of ACsP2Se8 (A: K, Rb, Cs).
Authors: Haynes Alyssa S. , Banerjee Abhishek , Saouma Felix O. , Otieno Calford O. , Jang Joon I. , Kanatzidis Mercouri G. 
Published: June 2016

AbstractThe title compounds are prepared from stoichiometric amounts of K2Se, and/or M2Se2 (M: Rb, Cs), P, and Se (500—550 °C, 10 h).
ChemInform Abstract: Syntheses, Crystal Structures and Magnetic Properties of Ternary Rare‐Earth Zirconium Selenides, Ln2ZrSe5 (Ln: Ce—Nd).
Authors: Guo Sheng‐Ping , Chi Yang , Guo Guo‐Cong 
Published: June 2016

AbstractCe2ZrSe5 (I), Pr2ZrSe5 (II), and Nd2ZrSe5 (III) are prepared by solid state reaction of CeO2 or Pr6O11 or Nd2O3, ZrO2, Se, and boron as the reductant in the molar ratio of 2:1:5:6, resp.
ChemInform Abstract: Two New Non‐Centrosymmetric n = 3 Layered Dion—Jacobson Perovskites: Polar RbBi2Ti2NbO10 and Nonpolar CsBi2Ti2TaO10.
Authors: Kim Hyung Gu , Tran T. Thao , Choi Woongjin , You Tae‐Soo , Halasyamani P. Shiv , Ok Kang Min 
Published: June 2016

AbstractSingle crystals of CsBi2Ti2TaO10 (I) are prepared by solid state reaction of Cs2CO3, Bi2O3, TiO2, and Ta2O5 (Pt crucible, 1000 °C, 24 h, 30% yield).