bluuebunny/crossref_metadata_2025_split huggingface dataset:
An autonomously self‐assembling dendritic DNA nanostructure for target DNA detection
Authors: Chandran Harish , Rangnekar Abhijit , Shetty Geetha , Schultes Erik A. , Reif John H. , LaBean Thomas H. 
Published: September 2012

AbstractThere is a growing need for sensitive and reliable nucleic acid detection methods that are convenient and inexpensive. Responsive and programmable DNA nanostructures have shown great promise as chemical detection systems. Here, we describe a DNA detection system employing the triggered self‐assembly of a novel DNA dendritic nanostructure. The detection protocol is executed autonomously without external intervention. Detection begins when a specific, single‐stranded target DNA strand (T) triggers a hybridization chain reaction (HCR) between two, distinct DNA hairpins (α and β). Each hairpin opens and hybridizes up to two copies of the other. In the absence of T, α and β are stable and remain in their poised, closed‐hairpin form. In the presence of T, α hairpins are opened by toe‐hold mediated strand‐displacement, each of which then opens and hybridizes two β hairpins. Likewise, each opened β hairpin can open and hybridize two α hairpins. Hence, each layer of the growing dendritic nanostructure can in principle accommodate an exponentially increasing number of cognate molecules, generating a high molecular weight nanostructure. This HCR system has minimal sequence constraints, allowing reconfiguration for the detection of arbitrary target sequences. Here, we demonstrate detection of unique sequence identifiers of HIV and Chlamydia pathogens.
Protein refolding using chemical refolding additives
Authors: Yamaguchi Satoshi , Yamamoto Etsushi , Mannen Teruhisa , Nagamune Teruyuki , Nagamune Teruyuki 
Published: September 2012

AbstractIn laboratories and manufacturing settings, a rapid and inexpensive method for the preparation of a target protein is crucial for promoting resesrach in protein science and engineering. Inclusion‐body‐based protein production is a promising method because high yields are achieved in the upstream process, although the refolding of solubilized, unfolded proteins in downstream processes often leads to significantly lower yields. The most challenging problem is that the effective condition for refolding is protein dependent and is therefore difficult to select in a rational manner. Accordingly, considerable time and expense using trial‐and‐error approaches are often needed to increase the final protein yield. Furthermore, for certain target proteins, finding suitable conditions to achieve an adequate yield cannot be obtained by existing methods. Therefore, to convert such a troublesome refolding process into a routine one, a wide array of methods based on novel technologies and materials have been developed. These methods select refolding conditions where productive refolding dominates over unproductive aggregation in competitive refolding reactions. This review focuses on synthetic refolding additives and describes the concepts underlying the development of reported chemical additives or chemical‐additive‐b
Monitoring and control of microbioreactors: An expert opinion on development needs
Authors: Gernaey Krist V. , Baganz Frank , Franco‐Lara Ezequiel , Kensy Frank , Krühne Ulrich , Luebberstedt Marc , Marx Uwe , Palmqvist Eva , Schmid Andreas , Schubert Frank , Mandenius Carl‐Fredrik 
Published: September 2012

AbstractThis perspective article is based on an expert panel review on microbioreactor applications in biochemical and biomedical engineering that was organized by the M3C (measurement, monitoring, modelling and control) Working Group of the European Section of Biochemical Engineering Science (ESBES) in the European Federation of Biotechnology (EFB). The aim of the panel was to provide an updated view on the present status of the subject and to identify critical needs and issues for furthering the successful development of microbioreactor monitoring and control. This will benefit future bioprocess development and in vitro toxicity testing. The article concludes with a set of recommendations for extended use and further development of microbioreactors.
Approach to Describe the Flow Conditions Relevant for Droplet Break Up During Emulsification of W/O Emulsions with Orifices
Authors: Wolf Frederik , Schuch Anna , Köhler Karsten , Schuchmann Heike P. 
Published: September 2012

AbstractEine indirekte Möglichkeit zur Einordnung der Strömung beim Emulgieren mit Lochblenden wird vorgestellt und der Einfluss der Strömungsform auf die Tropfengrößenverteilung der resultierenden W/O‐Emulsionen untersucht. Anhand verschiedener Bereiche im Verlauf des Durchflusskoeffizienten konnten unterschiedliche Strömungsformen identifiziert werden. In verschiedenen Strömungsbereichen wurden W/O‐Emulsionen zweier Stoffsysteme hergestellt und die Tropfengrößenverteilung der Emulsionen gemessen. Es konnte beobachtet werden, dass die resultierenden Tropfengrößenverteilungen der Emulsionen stark von der vorliegenden Strömungsform abhängen.
Resource Efficient Forming Technologies for Titanium and High Temperature Resistant Alloys
Authors: Erxleben Stefan , Fellmann Holger , Güther Volker , Janschek Peter , Lorenz Bernd 
Published: September 2012

AbstractHalbzeuge von Nichteisenwerkstoffen wie Titan‐, Nickel‐ oder Kobaltlegierungen sind einerseits nur in begrenzten Abmaß‐Sortimenten verfügbar sowie anderseits schwer verarbeitbar. Das führt in der Regel zu einer erheblichen Ineffizienz verbunden mit hohen Materialverlusten insbesondere in der Klein‐ und Mittelserienfertigung. Die vorgestellten Arbeiten zeigen erste Ergebnisse der Entwicklung inkrementeller Umformverfahren, um neue Möglichkeiten der ressourcen‐, energie‐ und kosteneffizienten Verarbeitung dieser Werkstoffe zu eröffnen. Diese partiell wirkenden Verfahren zeichnen sich durch vorteilhafte Besonderheiten aus.
An Integrated Process for Innovative Extraction of Metals from Kupferschiefer Mine Dumps, Germany
Authors: Kamradt Andreas , Borg Gregor , Schaefer Juliane , Kruse Stephanie , Fiedler Marco , Romm Phillip , Schippers Axel , Gorny Ralf , Bois Michael du , Bieligk Christin , Liebetrau Nadine , Nell Sylvie , Friedrich Bernd , Morgenroth Henning , Wotruba Hermann , Merkel Charlotte 
Published: September 2012

AbstractDumps in the Central German Mansfeld mining district have been investigated by a multi‐disciplinary research team to develop a holistic concept for the recovery of base and trace metals from low‐grade Kupferschiefer ore. Geochemical and mineralogical data from representative sampling indicate that the low‐grade Kupferschiefer dumps contain significant amounts of Cu (0.6 %) and Ag (up to 800 ppm), besides exploitable grades of Pb and Zn. Additionally to flotation and hydrometallurgy, first shake flask bioleaching experiments on otherwise untreated Kupferschiefer ore yield Cu recovery rates of up to 95 %. A total of 900 t Cu and 5 t Ag contained in black copper can thus be produced from the pilot dump of 100 000 m3 low‐grade Kupferschiefer ore. Additionally, large volumes of limestone waste, separated from the dumps by sensor‐based sorting, can be utilized as aggregate in the construction industry.
Drosophila LSD1‐CoREST demethylase complex regulates DPP/TGFβ signaling during wing development
Authors: Curtis Brenda J. , Zraly Claudia B. , Dingwall Andrew K. 
Published: September 2012

AbstractThe choice and timing of specific developmental pathways in organogenesis are determined by tissue‐specific temporal and spatial cues that are acted upon to impart unique cellular and compartmental identities. A consequence of cellular signaling is the rapid transcriptional reprogramming of a wide variety of target genes. To overcome intrinsic epigenetic chromatin barriers to transcription modulation, histone modifying and remodeling complexes are employed. The deposition or erasure of specific covalent histone modifications, including acetylation, methylation, and ubiquitination are essential features of gene activation and repression. We have found that the activity of a specific class of histone demethylation enzymes is required for the specification of vein cell fates during Drosophila wing development. Genetic tests revealed that the Drosophila LSD1‐CoREST complex is required for proper cell specification through regulation of the DPP/TGFβ pathway. An important finding from this analysis is that LSD1‐CoREST functions through control of rhomboid expression in an EGFR‐independent pathway. genesis
51:16–31, 2013. © 2012 Wiley Periodicals, Inc.
The origins of Atlantic salmon (Salmo salar L.) recolonizing the River Mersey in northwest England
Authors: Ikediashi Charles , Billington Sam , Stevens Jamie R. 
Published: September 2012

AbstractBy the 1950s, pollution had extirpated Atlantic salmon in the river Mersey in northwest England. During the 1970s, an extensive restoration program began and in 2001, an adult salmon was caught ascending the river. Subsequently, a fish trap was installed and additional adults are now routinely sampled. In this study, we have genotyped 138 adults and one juvenile salmon at 14 microsatellite loci from across this time period (2001–2011). We have used assignment analysis with a recently compiled pan‐European microsatellite baseline to identify their most probable region of origin. Fish entering the Mersey appear to originate from multiple sources, with the greatest proportion (45–60%, dependent on methodology) assigning to rivers in the geographical region just north of the Mersey, which includes Northwest England and the Solway Firth. Substantial numbers also appear to originate from rivers in western Scotland, and from rivers in Wales and Southwest England; nonetheless, the number of fish originating from proximal rivers to the west of the Mersey was lower than expected. Our results suggest that the majority of salmon sampled in the Mersey are straying in a southerly direction, in accordance with the predominantly clockwise gyre present in the eastern Irish Sea. Our findings highlight the complementary roles of improving water quality and in‐river navigability in restoring salmon to a river and underlines further the potential benefits of restoration over stocking as a long‐term solution to declining fish stocks.
The Simple Synthesis of Ferrocene Ligands from a Practitioner's Perspective
Authors: Butler Ian R. 
Published: September 2012

AbstractThis review is a personal account of the research carried out in our laboratories on the design and synthesis of ferrocene compounds used in catalysis, primarily as ligands but also in material science applications. The emphasis of the research has always been to find the simplest possible synthetic routes towards these ferrocene compounds, which may be used as convenient starting materials. This is why lithiation and quench methodology has been used extensively and successfully in most applications. It has taken many years to achieve the convenient synthesis of some very simple compounds such as 1,2‐dibromoferrocene and 1,2,3,4,5‐pentabromoferrocene, and the reasons for this are highlighted. The review concentrates on the synthesis of ferrocenophanes, ferrocenylphosphanes, ferrocenylalkylamines and their precursor compounds, describing some of their early coordination chemistry. Subsequently, the successful use of ferrocene‐based ligands in the Lucite Alpha process is discussed. The coordination chemistry of a selection of the ligands prepared is discussed, and the rationale behind the specific ligand design strategies is given. Included is some research material, previously unpublished, which serves to fill in gaps in the overview. Finally, some derivatives prepared for applications in material science are described from a synthetic standpoint.
3‐(2‐Furyl)‐2‐sulfanylpropenoic Acid as a Chelating Agent for Lead(II) and Diorganonolead(IV) Compounds – Chemical Behaviour and In Vitro Protective Effect against Dimethyllead(IV) Toxicity
Authors: Casas José S. , Castaño M. Victoria , Couce Maria D. , Sánchez Agustín , Sordo José , Torres M. D. , Vázquez López Ezequiel M. 
Published: September 2012

AbstractThe reaction of the title acid (H2fspa) with lead(II) acetate and dimethyl‐ or diphenyllead(IV) acetate in alcoholic medium gives the 1:1 complexes [Pb(fspa)] and [PbR2(fspa)] (R = Me, Ph). When the reaction was carried out in the presence of diisopropylamine (Q), the [HQ]2[Pb(fspa)2] and [HQ]2[PbPh2(fspa)2] derivatives formed in low yield. Additionally, the compounds Na[PbMe2(OAc)3], [PbPh2(fspa)(DMSO)] and [PbPh2(fspa)(DMSO)]·DMSO were also isolated as crystalline solids in subsequent crystallization processes. All these compounds were characterized by IR and NMR (1H and 13C) spectroscopy and, in some cases, by X‐ray diffractometry and 207Pb NMR spectroscopy. Pig renal proximal tubule LLC‐PK1 culture cells were used to determine in vitro the nephroprotective effect of H2fspa, [HQ]2[Zn(fspa)2], vitamin B1 and vitamin B6 against PbMe2(NO3)2 toxicity. The beneficial effects of the acid, the zinc(II) complex and/or their combinations with vitamin B1 (thiamine nitrate) are described.
Arene–Ruthenium Complexes with Phosphanylferrocenecarboxamides Bearing Polar Hydroxyalkyl Groups – Synthesis, Molecular Structure, and Catalytic Use in Redox Isomerizations of Allylic Alcohols to Carbonyl Compounds
Authors: Schulz Jiří , Císařová Ivana , Štěpnička Petr 
Published: September 2012

AbstractPhosphanylferrocenecarboxamide Ph2P–fc–CONHCH2CH2OH (1, fc = ferrocene‐1,1′‐diyl) and its newly synthesized congeners, Ph2P–fc–CONHCH(CH2OH)2 (2) and Ph2P–fc–CONHC(CH2OH)3 (3), were converted to a series of (η6‐arene)ruthenium complexes [(η6‐arene)RuCl2(L‐κP)] 5–7, where arene is benzene, p‐cymene, and hexamethylbenzene and L = 1–3. All compounds were characterized by multinuclear NMR and IR spectroscopy, by mass spectrometry, and by elemental analysis. The molecular structures of 2, 3, 3O (a phosphane oxide resulting from the oxidation of 3), 5c·CH2Cl2, and 6c·Et2O were determined by single‐crystal X‐ray diffraction analysis. The ruthenium complexes were further evaluated as catalysts in the redox isomerization of allyl alcohols to carbonyl compounds. Complex [(η6‐p‐cymene)RuCl2(1‐κP)] (5b) proved to be a particularly attractive catalyst, being both readily available and catalytically active. Substrates with unsubstituted double bonds were cleanly isomerized with this catalyst in 1,2‐dichloroethane (0.5 mol‐% Ru, 80 °C), whereas for those bearing substituents at the double bond (particularly in the position closer to the OH group) lower conversions and selectivities were achieved. A similar trend was noted when pure water was used as the solvent, except that the best results (complete conversion with 2 mol‐% Ru) were seen for 1,3‐diphenylallyl alcohol, the most hydrophobic substrate.
Click Synthesis and Redox Chemistry of Mono‐ and Heterobimetallic Triazolyl and Triazolium‐Ferrocene and Cobalticinium Complexes
Authors: Rapakousiou Amalia , Mouche Claire , Duttine Mathieu , Ruiz Jaime , Astruc Didier 
Published: September 2012

AbstractMono‐ and heterobimetallic triazolylferrocene and cobalticinium complexes and triazolium derivatives were synthesized by click reactions between the ethynylmetallocenes and benzyl azide or (azidomethyl)ferrocene followed by methylation reactions, respectively. Cyclic voltammetry data shed light on the electron‐withdrawing character of the 1,2,3‐triazolyl and triazolium substituents of the metallocenes, and cathodic reduction of the triazolium group was found to be irreversible even at –50 °C. Chemical reduction of orange triazolylcobalticinium hexafluorophosphate using NaBH4 yielded a mixture of red isomeric triazolyl η4‐cyclopentadiene–cobalt–η5‐cyclopentadienyl complexes, whereas reduction by the single‐electron reductant [FeICp(η6‐C6Me6)] yielded the brown 19‐electron triazolylcobaltocene.
A Stereoselective Route to Aza‐C‐aryl Glycosides from Arynes and Chiral Nitrones
Authors: Khangarot Rama Kanwar , Kaliappan Krishna P. 
Published: September 2012

AbstractArynes are regarded as potential and versatile intermediates in organic synthesis. These highly‐reactive, strained and kinetically unstable species have numerous applications in synthetic chemistry. In this article, a highly‐diasteroselective and efficient 1,3‐dipolar cycloaddition reaction between a range of arynes and sugar‐derived cyclic nitrones leading to an interesting class of sugar‐based benzo[d]isoxazolines is described. These benzo[d]isoxazolines upon selective N–O bond cleavage provide various substituted aza‐C‐aryl glycosides in good yield. These substituted pyrrolidine derivatives are chiral aminophenols and could be potential chiral ligands and organocatalysts in asymmetric synthesis.
Colorimetric Probe for the Detection of Thiols: The Dihydroazulene/Vinylheptafulvene System
Authors: Cacciarini Martina , Della Pia Eduardo A. , Nielsen Mogens B. 
Published: September 2012

AbstractA new application of the dihydroazulene/vinylheptafulvene (DHA/VHF) system as a chemodosimeter for thiols is reported herein. A color change visible to the naked eye can be detected in acetonitrile/water (4:1) in the presence of cysteine and alkanethiols but not with other amino acids. The higher reactivity of DHA towards cysteine compared with VHF has been demonstrated. The easy synthesis of the main core and its versatility in terms of structural and physicochemical changes are essential elements for developing a new family of thiol‐specific probes with higher selectivity and sensitivity than the reported prototype.
Phosphane‐Mediated Domino Synthesis of Tetrasubstituted Furans from Simple Terminal Activated Olefins
Authors: Wang Jianfang , Zhou Rong , He Zheng‐Rong , He Zhengjie 
Published: September 2012

AbstractConvenient and highly efficient syntheses of tetrasubstituted furans with flexible substituent patterns from simple and readily available starting materials have been developed. Under very mild conditions, with the mediation of stoichiometric nBu3P, simple terminal activated olefins and acyl chlorides or anhydrides smoothly furnish tetrasubstituted furans in modest to excellent yields. This synthetic strategy features a flexible selection of substituent pattern and a C‐acylation/O‐acylation/C‐acylation/intramolecular Wittig reaction multiple domino assembly sequence.
Palladium‐Catalyzed Mono‐α‐arylation of Carbonyl‐Containing Compounds with Aryl Halides using DalPhos Ligands
Authors: Crawford Sarah M. , Alsabeh Pamela G. , Stradiotto Mark 
Published: September 2012

AbstractWe report the extension and optimization of the [Pd(cinnamyl)Cl]2/DalPhos catalyst system, previously found effective for the mono‐α‐arylation of acetone, to the mono‐α‐arylation of a variety of carbonyl‐containing compounds with aryl halides and heteroaryl halides. Aryl methyl ketones, heteroaryl methyl ketones, propiophenones, malonates, and methoxyacetone can be α‐arylated under relatively mild conditions and in good yields. We also report the limitations of the ligand/catalyst system towards other classes of carbonyl‐containing compounds.
Searching for the Hidden Hydrides: The Competition between Alkene Isomerization and Metathesis with Grubbs Catalysts
Authors: Ashworth Ian W. , Hillier Ian H. , Nelson David J. , Percy Jonathan M. , Vincent Mark A. 
Published: September 2012

AbstractAlthough Grubbs metathesis catalysts have enabled syntheses of a range of molecules, alkene isomerization, a known and problematic side reaction, is poorly understood. Several mechanisms which have been advanced to account for isomerization were studied by using electronic structure calculations. The pathway catalyzed by a ruthenium hydride emerged as the most facile process by a significant margin. For the first time, we have obtained experimental evidence for the presence of this species in a metathesis‐active system.
DNA polymerase kappa microsatellite synthesis: Two distinct mechanisms of slippage‐mediated errors
Authors: Baptiste Beverly A. , Eckert Kristin A. 
Published: September 2012

AbstractMicrosatellite tandem repeats are frequent sites of strand slippage mutagenesis in the human genome. Microsatellite mutations often occur as insertion/deletion of a repeat motif (unit‐based indels), and increase in frequency with increasing repeat length after a threshold is reached. We recently demonstrated that DNA polymerase κ (Pol κ) produces fewer unit‐based indel errors within dinucleotide microsatellites than does polymerase δ. Here, we examined human Pol κ's error profile within microsatellite alleles of varying sequence composition and length, using an in vitro HSV‐tk gap‐filling assay. We observed that Pol κ displays relatively accurate synthesis for unit‐based indels, using di‐ and tetranucleotide repeat templates longer than the threshold length. We observed an abrupt increase in the unit‐based indel frequency when the total microsatellite length exceeds 28 nucleotides, suggesting that extended Pol κ protein–DNA interactions enhance fidelity of the enzyme when synthesizing these microsatellite alleles. In contrast, Pol κ is error‐prone within the HSV‐tk coding sequence, producing frequent single‐base errors in a manner that is highly biased with regard to sequence context. Single‐nucleotide errors are also created by Pol κ within di‐ and tetranucleotide repeats, independently of the microsatellite allele length and at a frequency per nucleotide similar to the frequency of single base errors within the coding sequence. These single‐base errors represent the mutational signature of Pol κ, and we propose them a mechanism independent of homology‐stabilized slippage. Pol κ's dual fidelity nature provides a unique research tool to explore the distinct mechanisms of slippage‐mediated mutagenesis.Environ. Mol. Mutagen., 2012. © 2012 Wiley Periodicals, Inc.
DNA polymerase zeta generates clustered mutations during bypass of endogenous DNA lesions inSaccharomyces cerevisiae
Authors: Stone Jana E. , Lujan Scott A. , Kunkel Thomas A. 
Published: September 2012

AbstractMultiple sequence changes that are simultaneously introduced in a single DNA transaction have a higher probability of altering gene function than do single base substitutions. DNA polymerase zeta (Pol ζ) has been shown to introduce such clustered mutations under specific selective and/or DNA damage‐producing conditions. In this study, a forward mutation assay was used to determine the specificity of spontaneous mutations generated inSaccharomyces cerevisiaewhen either wild‐type Pol ζ or a mutator Pol ζ variant (rev3‐L979F) bypasses endogenous lesions. Mutagenesis in strains proficient for nucleotide excision repair (NER) was compared to mutagenesis in NER‐deficient strains that retain unrepaired endogenous DNA lesions in the genome. Compared to NER‐proficient strains, NER‐deficientrad14Δstrains have elevated mutation rates that depend on Pol ζ. Rates are most strongly elevated for tandem base pair substitutions and clusters of multiple, closely spaced mutations. Both types of mutations depend on Pol ζ, but not on Pol η. Rates of each are further elevated in yeast strains bearing therev3‐979Fallele. The results indicate that when Pol ζ performs mutagenic bypass of endogenous, helix‐distorting lesions, it catalyzes a short track of processive, error‐prone synthesis. We discuss the implications of this unique catalytic property of Pol ζ to its evolutionary conservation and possibly to multistage carcinogenesis.Environ. Mol. Mutagen., 2012. © 2012 Wiley Periodicals, Inc.