bluuebunny/crossref_metadata_2025_split huggingface dataset:
The peridotite ridge province in the southern Iberia Abyssal Plain: Seismic constraints revisited
Authors: Minshull T. A. , Dean S. M. , Whitmarsh R. B. 
Published: February 2014

AbstractThe west Iberia margin has become the type example of a magma‐starved margin in which extension during breakup led to the exhumation of mantle rocks apparently over a broad area. Much of our understanding of this process is based on geophysical and drilling data from the southern Iberia Abyssal Plain, where the seaward part of the region of exhumed mantle is composed of a series of margin‐parallel basement ridges. Here we analyze wide‐angle and normal‐incidence seismic data from a series of intersecting profiles across this peridotite ridge province and develop a three‐dimensional picture of its structure. Using these seismic data, we infer a location and age (magnetic anomaly M1; 125–127 Ma) of first‐formed oceanic crust in this region that are consistent with Ocean Drilling Program data and data from the conjugate margin. We infer that the peridotite ridge province is about 70 km wide with strong serpentinization (>75%) at the top of the basement reducing to much lower degrees (< 25%) around 2 km below. We map the geometry of some prominent reflectors on the landward margin of the peridotite ridge province that likely represent detachment faults and show that one of these has a domal structure similar to that of detachment faults at slow to ultraslow spreading mid‐ocean ridges.
Organocatalytic Asymmetric Conjugate Addition of 2‐Oxindole‐3‐Carboxylate Esters to 2‐Phthalimido Acrylates: Efficient Synthesis of Cγ‐tetrasubstituted α‐Amino Acid Derivatives
Authors: Gao Juan , Chen Jia‐Rong , Duan Shu‐Wen , Li Tian‐Ren , Lu Liang‐Qiu , Xiao Wen‐Jing 
Published: February 2014

AbstractAn organocatalytic asymmetric conjugate addition of 2‐oxindole‐3‐carboxylate esters to 2‐phthalimidoacrylates catalyzed by a quinine‐derived thiourea is described. The reaction provides efficient access to a variety of quaternary oxindole based Cγ‐tetrasubstituted α‐amino acid derivatives in good to excellent yields (up to 96 %) with moderate to good enantioselectivity (up to 90 % ee). The opposite enantiomers of the products can also be obtained with comparable yields and stereoselectivity by simply using a quinidine‐derived thiourea catalyst.
Developing a pig model for crypt fenestration‐induced localized hypoplastic enamel defects in humans
Authors: Skinner Mark F. , Rodrigues Antonia T. , Byra Chris 
Published: February 2014

ABSTRACTHypoplastic pits on human deciduous canine teeth are attributed to nutritionally induced thinning of the crypt wall prior to eruption, exposing ameloblasts to unspecified physical trauma through the fenestration. Traditionally known as localized hypoplasia of the primary canine (LHPC), this little‐understood condition is reported in fields ranging from public health to bioarchaeology. We propose the defect be termed a ‘crypt fenestration hypoplastic enamel defect’ (CFED) to reflect that an analogous lesion is created postnatally on maxillary molars of pigs. Pigs are accepted as a suitable proxy for many studies in human biology. We compare fenestration defects and CFEDs between 50 Sick Pen pigs, who died naturally, and 20 Controls. Observations were made of the presence, number and size of fenestrations in molar crypts. CFEDs were counted on erupted deciduous last molars and permanent first molars. Signs of being underweight and cranio‐dental infection at death were recorded. Sick pen pigs show significantly more fenestrations at death and CFEDs acquired before death. These conditions co‐occur with infection and poor growth. The deep fibers of temporalis muscle lie adjacent to the crypt wall of maxillary molars. We propose that contraction of this muscle during suckling and chewing creates large compressive forces against fenestrated bony surfaces sufficient to have physiological consequences for physically unprotected ameloblasts. While we conclude that a pig model is appropriate to study fenestration‐induced enamel defects, this naturalistic experiment leaves unresolved whether osteopenia in pigs, and by extension in human infants, is due to disease and/or malnutrition. Am J Phys Anthropol 154:239–250, 2014. © 2014 Wiley Periodicals, Inc.
Synthese hochsubstituierter 3‐Formylfurane über eine Kaskade aus Gold(I)‐katalysierter Oxidation, 1,2‐Alkinylwanderung und Cyclisierung
Authors: Wang Tao , Shi Shuai , Hansmann Max M. , Rettenmeier Eva , Rudolph Matthias , Hashmi A. Stephen K. 
Published: February 2014

Abstract3‐Formylfuranmotive bilden die Grundstrukturen einer Reihe bioaktiver Naturstoffe, allerdings sind für ihre Herstellung nur wenige Verfahren bekannt, die zudem nicht atomökonomisch sind: Sie erfordern mehrere Stufen oder harsche Reaktionsbedingungen und verlaufen unselektiv. Hier berichten wir über eine effiziente Gold(I)‐katalysierte Kaskadenreaktion, die aus leicht zugänglichen Ausgangsverbindungen zu 3‐Formylfuranen führt. Eine breite Palette von 3‐Formylfuranen wurde aus den jeweiligen symmetrischen und unsymmetrischen 1,4‐Diin‐3‐olen in Gegenwart eines N‐Oxids in guten bis ausgezeichneten Ausbeuten erhalten. Isotopenmarkierungsexperimente und DFT‐Rechnungen sprechen für einen Mechanismus, bei dem nach einer einleitenden Sauerstoffübertragung eine 1,2‐Alkinylwanderung gegenüber einer Hydridwanderung bevorzugt ist; dem schließt sich eine Cyclisierung zum gewünschten Furangrundgerüst an.
Kontrolle über Bildung und Bruch kovalenter Verknüpfungen durch Licht
Authors: Göstl Robert , Hecht Stefan 
Published: February 2014

AbstractDer Wunsch nach Bauteilverkleinerung und die wachsende Komplexität von Strukturen auf dem Gebiet der Nanotechnologie verlangen nach der präzisen und kontrollierten Bildung kovalenter Bindungen auf molekularer Ebene. Eine solche Kontrolle erfordert jedoch den Einsatz externer Stimuli mit herausragender räumlicher, zeitlicher und energetischer Auflösung. Mit Licht adressierbare Schalter sind deshalb exzellente Kandidaten für Systeme, die eine reversible Photokontrolle über kovalente chemische Ver‐ und Entknüpfungen ermöglichen. Hier stellen wir ein solches System vor, das ausschließlich durch die Bestrahlung mit Licht unterschiedlicher Farbe kontrolliert werden kann. Zu diesem Zweck wurde ein Furyl‐substituiertes photoschaltbares Diarylethen konstruiert, das eine reversible Diels‐Alder‐Reaktion mit Maleinimid eingehen kann. Unser System verspricht Anwendungsmöglichkeiten in allen Gebieten, die schon jetzt die Vorteile von reversiblen Diels‐Alder‐Reaktionen nutzen.
Copper‐Catalyzed Intramolecular C(sp3)H and C(sp2)H Amidation by Oxidative Cyclization
Authors: Wang Zhen , Ni Jizhi , Kuninobu Yoichiro , Kanai Motomu 
Published: February 2014

AbstractThe first copper‐catalyzed intramolecular C(sp3)H and C(sp2)H oxidative amidation has been developed. Using a Cu(OAc)2 catalyst and an Ag2CO3 oxidant in dichloroethane solvent, C(sp3)H amidation proceeded at a terminal methyl group, as well as at the internal benzylic position of an alkyl chain. This reaction has a broad substrate scope, and various β‐lactams were obtained in excellent yield, even on gram scale. Use of CuCl2 and Ag2CO3 under an O2 atmosphere in dimethyl sulfoxide, however, leads to 2‐indolinone selectively by C(sp2)H amidation. Kinetic isotope effect (KIE) studies indicated that CH bond activation is the rate‐determining step. The 5‐methoxyquinolyl directing group could be removed by oxidation.
Autoamplification of Molecular Chirality through the Induction of Supramolecular Chirality
Authors: van Dijken Derk Jan , Beierle John M. , Stuart Marc C. A. , Szymański Wiktor , Browne Wesley R. , Feringa Ben L. 
Published: February 2014

AbstractThe novel concept for the autoamplification of molecular chirality, wherein the amplification proceeds through the induction of supramolecular chirality, is presented. A solution of prochiral, ring‐open diarylethenes is doped with a small amount of their chiral, ring‐closed counterpart. The molecules co‐assemble into helical fibers through hydrogen bonding and the handedness of the fibers is biased by the chiral, ring‐closed diarylethene. Photochemical ring closure of the open diarylethene yields the ring‐closed product, which is enriched in the template enantiomer.
A Concerted Transfer Hydrogenolysis: 1,3,2‐Diazaphospholene‐Catalyzed Hydrogenation of NN Bond with Ammonia–Borane
Authors: Chong Che Chang , Hirao Hajime , Kinjo Rei 
Published: February 2014

Abstract1,3,2‐diazaphospholenes catalyze metal‐free transfer hydrogenation of a NN double bond using ammonia–borane under mild reaction conditions, thus allowing access to various hydrazine derivatives. Kinetic and computational studies revealed that the rate‐determining step involves simultaneous breakage of the BH and NH bonds of ammonia–borane. The reaction is therefore viewed as a concerted type of hydrogenolysis.
Diprotonated [28]Hexaphyrins(1.1.1.1.1.1): Triangular Antiaromatic Macrocycles
Authors: Ishida Shin‐ichiro , Higashino Tomohiro , Mori Shigeki , Mori Hirotaka , Aratani Naoki , Tanaka Takayuki , Lim Jong Min , Kim Dongho , Osuka Atsuhiro 
Published: February 2014

AbstractProtonation of meso‐aryl [28]hexaphyrins(1.1.1.1.1.1) triggered conformational changes. Whereas protonation with trifluoroacetic acid led to the formation of monoprotonated Möbius aromatic species, protonation with methanesulfonic acid led to the formation of diprotonated triangular antiaromatic species. A peripherally hexaphenylated [28]hexaphyrin was rationally designed and prepared to undergo diprotonation to favorably afford a triangular‐shaped antiaromatic species.
Size‐Selective Complexation and Extraction of Endohedral Metallofullerenes with Cycloparaphenylene
Authors: Nakanishi Yusuke , Omachi Haruka , Matsuura Sanae , Miyata Yasumitsu , Kitaura Ryo , Segawa Yasutomo , Itami Kenichiro , Shinohara Hisanori 
Published: February 2014

AbstractA new strategy for the non‐chromatographic extraction of metallofullerenes from solutions of arc‐processed raw soot is based on the size‐selective complexation with cycloparaphenylene (CPP). [11]CPP has a high affinity for Mx@C82 (x=1, 2); for example, Gd@C82 can be selectively extracted from a fullerene mixture by the addition of [11]CPP. This approach should open new opportunities in metallofullerene chemistry, including for the bulk extraction of metallofullerenes.
Deracemization By Simultaneous Bio‐oxidative Kinetic Resolution and Stereoinversion
Authors: Schrittwieser Joerg H. , Groenendaal Bas , Resch Verena , Ghislieri Diego , Wallner Silvia , Fischereder Eva‐Maria , Fuchs Elisabeth , Grischek Barbara , Sattler Johann H. , Macheroux Peter , Turner Nicholas J. , Kroutil Wolfgang 
Published: February 2014

AbstractDeracemization, that is, the transformation of a racemate into a single product enantiomer with theoretically 100 % conversion and 100 % ee, is an appealing but also challenging option for asymmetric synthesis. Herein a novel chemo‐enzymatic deracemization concept by a cascade is described: the pathway involves two enantioselective oxidation steps and one non‐stereoselective reduction step, enabling stereoinversion and a simultaneous kinetic resolution. The concept was exemplified for the transformation of rac‐benzylisoquinolines to optically pure (S)‐berbines. The racemic substrates were transformed to optically pure products (ee>97 %) with up to 98 % conversion and up to 88 % yield of isolated product.
Pretreatment and kinetics of oil extraction from algae for biodiesel production
Authors: Valizadeh Derakhshan Mehrab , Nasernejad Bahram , Dadvar Mitra , Hamidi Mohammad 
Published: February 2014

ABSTRACTIn this study, extraction of lipid from algal sp. Chlorella vulgaris is investigated based on Bligh and Dyer method employing methanol and chloroform on wet biomass. Optimization methodology was established on comparison of pretreatment methods as well as investigation of ultrasonication and stirrer parameters to enhance cell disruption. It was found that biomass with water/solid proportion (w/s = 5) operating temperature of 50 °C both for ultrasonication and shaking, 5 min ultrasonication with further 3 h of stirring with 200 rpm is the best set of parameters for breakdown of cell envelops, and using these parameters, total extraction of 22.07% was obtained. Kinetic study of breakdown was carried out with further full‐factorial investigation of extraction (%) vs time and temperature. Using Arrhenius equation, activation energy of about 34.73 kJ/mol was obtained for this algal sp. with R2 = 97.81%. Further analysis using analysis of variance showed that when using lower temperatures, sudden increase of extraction occurs in longer times, and vice versa, hence emphasizing the interaction thereof. It was also found that temperature plays the vital role among all examined parameters. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
Chemical and physical modifications of electrospun keratin nanofibers induced by heating treatments
Authors: Varesano Alessio , Vineis Claudia , Tonetti Cinzia , Ramírez Diego Omar Sánchez , Mazzuchetti Giorgio 
Published: February 2014

ABSTRACTIn this study, we aimed to examine to study the effects of heating treatments on wool‐derived keratin nanofibers obtained by electrospinning. Interestingly, the keratin nanofibers did not lose their nanofibrous shape at high temperatures. On the contrary, the diameter of keratin nanofibers significantly decreased after heating. Even the chemical structure of the keratin was not significantly altered by heating, as observed by IR spectroscopy, except for a shoulder at 1720 cm−1 and the amide III band. The spectral feature changes matched the formation of crosslinking amide bonds between protein chains well. Moreover, for various applications, it is essential that nanofibers are stable in water. Heating treatments were carried out at different temperatures and times to assess what heating conditions gave the keratin nanofibers water stability. Finally, no significant changes in the thermal behavior were observed in the samples after heating treatments compared to the untreated keratin nanofibers; this was a sign of negligible or slight degradations of the protein chains. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40532.
Pullulan‐based films and coatings for food packaging: Present applications, emerging opportunities, and future challenges
Authors: Farris Stefano , Unalan Ilke Uysal , Introzzi Laura , Fuentes‐Alventosa José Maria , Cozzolino Carlo A. 
Published: February 2014

ABSTRACTSocietal and industrial demands for lower environmental impact, cost effectiveness, and high‐performance goods and services are increasingly impacting the choice of technologies which are developed and deployed in consumer products. Like many other sectors, food packaging is moving to new technologies; the use of biopolymers is one of the most promising strategies toward an optimized use of traditional packaging materials (e.g., oil‐based plastics) without impairing the goal of extending shelf life. Among other food packaging materials, pullulan is attracting much attention due to its unique features. The goal of this review is to provide an overview of current and emerging applications of pullulan within the food packaging sector. In particular, the functional properties of interest for the food packaging industry will be discussed in light of the physicochemical attributes of this exopolysaccharide. Future challenges that may dictate the successful penetration of pullulan in the food packaging market are also outlined. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40539.
The Application of CdSe Quantum Dots with Multicolor Emission as Fluorescent Probes for Cell Labeling
Authors: Zhao Mei‐Xia , Li Yang , Zeng Er‐Zao , Wang Chao‐Jie 
Published: February 2014

AbstractHerein, highly luminescent CdSe quantum dots (QDs) with emissions from the blue to the red region of visible light were synthesized by using a simple method. The emission range of the CdSe QDs could be tuned from λ=503 to 606 nm by controlling the size of the CdSe QDs. Two amino acids, L‐tryptophan (L‐Trp) and L‐arginine (L‐Arg), were used as coating agents. The quantum yield (QY) of CdSe QDs (green color) with an optimized thickness could reach up to 52 %. The structures and compositions of QDs were examined by using X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Optical properties were studied by using UV/Vis and photoluminescence (PL) spectroscopy and a comparison was made between uncoated and coated CdSe QDs. The amino acid‐modified β‐cyclodextrin (CD)‐coated CdSe QDs presented lower cytotoxicity to cells for 48 h. Furthermore, amino acid‐modified β‐CD‐coated green CdSe QDs in HepG2 cells were assessed by using confocal laser scanning fluorescence microscopy. The results showed that amino acid‐modified β‐CD‐coated green CdSe QDs could enter tumor cells efficiently and indicated that biomolecule‐coated QDs could be used as a potential fluorescent probe.
Stochastic Networked Control Systems with Dynamic Protocols
Authors: Antunes Duarte , Hespanha João P. , Silvestre Carlos 
Published: February 2014

AbstractWe consider networked control systems in which sensors, controllers, and actuators communicate through a shared network that introduces stochastic intervals between transmissions, delays, and packet drops. Access to the communication medium is mediated by a protocol that determines which node (one of the sensors, one of the actuators, or the controller) is allowed to transmit a message at each sampling/actuator‐update time. We provide conditions for mean exponential stability of the networked closed loop in terms of matrix inequalities, both for investigating the stability of given protocols, such as static round‐robin protocols and dynamic maximum error first‐try once discard protocols, and conditions to design new dynamic protocols. The main result entailed by these conditions is that, if the networked closed loop is stable for a static protocol, then we can provide a dynamic protocol for which the networked closed loop is also stable. The stability conditions also allow for obtaining an observer‐protocol pair that reconstructs the state of a linear time invariant plant in a mean exponential sense and for less conservative stability results than other conditions previously appearing in the literature.
Understanding and attributing the Euro‐Russian summer blocking signatures
Authors: Ruti Paolo M. , Dell'Aquila A. , Giorgi F. 
Published: February 2014

AbstractIn this work, we focus on summer blocking events over the Euro‐Russian region related with heat waves. An analysis of the main characteristics of summer Euro‐Russian blocking events in global Reanalysis as well as in the 20th century CLIVAR atmospheric simulations is carried out to assess whether anthropogenic forcing might have affected the blocking events occurrence and the associated heat waves strength in recent decades. Over the Euro‐Russian region, blocking episodes, associated to warm events over Northern and Central Europe, become significantly longer in the second half of the century when the anthropogenic forcing is included in the simulations.
Zum Potenzial von Kohlenstofffaserverbundwerkstoffen in Bauanwendungen
Authors: Schmohl Andreas , Adamow Katharina , Martens Nadine , Breuer Klaus 
Published: February 2014

AbstractDer Beitrag diskutiert die Anwendung von Kohlenstofffaserverbundwerkstoffen im Bauwesen. Es wird aufgezeigt, dass Kohlenstofffaserverbundwerkstoffe in bestimmten Bauanwendungen bereits etabliert sind, z. B. zur Verstärkung der Statik von Gebäuden und Brücken sowie als Konstruktionswerkstoff. Andererseits sollen spezielle Potenziale des Materials jenseits der mechanischen Eigenschaften identifiziert werden, die sich für Anwendungen im Bauwesen ableiten lassen. Ausgewählte Anwendungsbeispiele, die sich auf vier charakteristischen Eigenschaften des Materials bzw. des Fertigungsprozesses zurückführen lassen, werden beschrieben: 1) Nutzung der Anisotropie zur Konstruktion flexibler und zugleich steifer Bauteile, 2) Integration von (Multi‐)Funktionalitäten, 3) Nutzung des geringen Wärmeausdehnungskoeffizienten und 4) Einsatz von recyclierten Kohlenstofffasern in anorganischer Matrix.Potential of carbon fibre composites in civil engineering applications. The paper discusses the application of carbon fibre composite materials in the building industry. It shows that carbon fibre composites are already established in certain areas of civil engineering, e.g. for the strengthening of the statics of buildings and bridges and as construction material. On the other hand special potential of the material, apart from mechanical features, which are advantageous in construction engineering, are identified. Selected examples of specific applications deduced from four characteristic properties of the material and the manufacturing process respectively, are described: 1) Utilisation of the anisotropy for the construction of flexible and at the same time stiff construction components, 2) integration of (multi‐)functionalities, 3) utilisation of the low thermal expansion coefficient and 4) application of recycled carbon fibres in inorganic matrices.
An undergraduate study of two transcription factors that promote lateral root formation
Authors: Bargmann Bastiaan O. R. , Birnbaum Kenneth D. , Brenner Eric D. 
Published: February 2014

AbstractWe present a lab that enables students to test the role of genes involved in the regulation of lateral roots growth in the model plant Arabidopsis thaliana. Here, students design an experiment that follows the effects of the hormone auxin on the stimulation of genes involved in the formation of lateral root initials. These genes, known as lateral organ boundary domain containing protein (LBD) genes, are upregulated in the presence of auxin as part of a multistep molecular and biochemically controlled pathway. Depending on which LBD gene is tested, and the stage of root development, expression patterns are localized in a discrete and punctate fashion at the site of lateral root initials (LBD33), or reveal a broader localization pattern (LBD16). Students view expression using the reporter gene GUS (beta‐glucuronidase). Before GUS staining, students view root growth in a “pseudo‐aseptic” agar‐based environment that allows complete visualization of whole root development to determine the proper stage to test molecular expression. © 2014 by The International Union of Biochemistry and Molecular Biology, 42(3):XXXXX–XXXXX, 2014.
Fast separation of native proteins using sub‐2 µm nonporous silica particles in a chromatographic cake
Authors: Niu Ruijuan , Min Yi , Geng Xindu 
Published: February 2014

ABSTRACTA novel method for the fast separation of native proteins was investigated using sub‐2 µm nonporous silica packing inside a chromatographic cake having a diameter much larger than its thickness. Various silica‐based particles ranging from 630 nm to 1.2 µm were synthesized and chemically modified with polyethylene glycol 600. The packing material was laterally packed into a series of chromatographic cakes containing the same diameter (10 mm) and different thicknesses, ranging from 2 to 10 mm, and tested by hydrophobic interaction chromatography. The results showed that the sub‐2 µm NPS particles in a small chromatographic cake were found to have a high efficiency at a flow rate of 10 mL/min and a backpressure of <20 MPa. The effect of the thickness of the chromatographic cake on the resolution of the proteins was also investigated and it was found that too short a column length could dramatically decrease the protein resolution; the minimum column length was also qualitatively evaluated. The presented method is expected to be useful for routine analysis of native and/or intact proteins in hospitals and as a tool for the fast screening protein drugs and optimization of experimental laboratory conditions. Copyright © 2014 John Wiley & Sons, Ltd.