bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of Genetic Variability in Saffron (Crocus sativus L.) Germplasm for Morphological and Quality Traits
Authors: Fazil S  , Iqbal Asif M , Sofi M. D , Mahdi SS , Jeelani F  , Khan MH , Dar NA , Mir GH , Shikari Asif B. , Bangroo S. , Soliha. M  , Ahngar Tanveer A.
Published: May 2024

Crop improvement relies heavily on the genetic variability present within the gene pool. Understanding the nature and extent of genetic variations within germplasm is essential for breeders to design effective breeding programs. The present investigation comprised of 35 germplasm lines of saffron (Crocus sativus L.) conducted in a RCBD with three replications at ARSSSS, SKUAST-K, Pampore. Observations were recorded on morphological, yield, and quality traits for the assessment of genetic variability and other parameters. The findings revealed significant differences among germplasm lines, indicating substantial variability across all traits. Phenotypic coefficient of variation consistently exceeded the genotypic coefficient of variation (GCV) for all characters, with stigma length exhibiting the highest PCV (25.24%) and GCV (24.08%), while the number of days taken to first flush demonstrated the lowest PCV (1.84%) and GCV (1.66%). The study reported high broad-sense heritability for all traits, ranging from 75.1% for corm diameter to 99.2% for the number of leaves. Notably, safranal content, stigma length, and fresh weight of pistil displayed the highest heritability and genetic advance over mean. Correlation analysis revealed significant associations, with dry weight of stigma exhibiting positive correlations with various traits, including pistil length, stigma length, and safranal content, while displaying negative correlations with outer tepal width, inner tepal width, and number of leaves per corm/plant. Path coefficient analyses underscored the importance of traits such as pistil length, fresh weight of pistil, stigma length, and style length and the UPGMA clustering method categorized saffron genotypes into five clusters. The study reports the morphological characterization and genetic variability of diverse saffron genotypes, which could be used for future saffron breeding programs especially clonal selection from the available germplasm resources is of prime importance.
Basic Confocal Microscopy
Authors: Smith Carolyn L.
Published: July 2011

This unit introduces the reader to the basic principles of confocal microscopy and the design and capabilities of current confocal microscopes. The advantages and disadvantages of confocal microscopy compared to other techniques for fluorescence imaging are described. There are also practical guidelines for sample preparation and optimization of imaging parameters, as well as examples of some of the applications of confocal microscopy.Curr. Protoc. Neurosci. 56:2.2.1‐2.2.18. © 2011 by John Wiley & Sons, Inc.
In Vitro Analysis of Mouse Mesencephalic Neural Crest Development
Authors: Ito Kazuo , Fujita Kyohei
Published: July 2011

The neural crest is a unique structure in vertebrates. Neural crest cells play important roles in the formation of organs that characterize the vertebrate body plan. In this unit, we describe a primary culture method for mouse mesencephalic neural crest cells. The neural crest cells cultured by this method actively proliferate and differentiate into various cell types that originate from cranial neural crest cells, such as chondrocytes, neurons, and glia. Therefore, this primary culture method is useful for analyzing the development of mouse mesencephalic neural crest cells. Curr. Protoc. Neurosci. 56:3.23.1‐3.23.8. © 2011 by John Wiley & Sons, Inc.
Quantitation of DNA and RNA with Absorption and Fluorescence Spectroscopy
Authors: Gallagher Sean R.
Published: July 2011

Quantitation of nucleic acids is a fundamental tool in molecular biology that requires accuracy, reliability, and the use of increasingly smaller sample volumes. This unit describes the traditional absorbance measurement at 260 nm and three more sensitive fluorescence techniques employing Hoechst 33258, ethidium bromide, and PicoGreen. The range of the assays covers 25 pg/ml to 50 µg/ml. Absorbance at 260 nm has an effective range from 1 to 50 µg/ml; Hoechst 33258 from 0.01 to 15 µg/ml; ethidium bromide from 0.1 to 10 µg/ml; and PicoGreen from 25 to 1000 pg/ml.Curr. Protoc. Neurosci. 56:A.1K.1‐A.1K.14. © 2011 by John Wiley & Sons, Inc.
Recombineering‐Based Procedure for Creating BAC Transgene Constructs for Animals and Cell Lines
Authors: Hollenback Steven M. , Lyman Suzanne , Cheng JrGang
Published: July 2011

The use of BAC/P1 as a vector for the generation of a transgene has gained popularity after the genomic annotation of many organisms was completed (often based on the respective BAC library). Large‐scale generation of BAC transgenic mice has proven that BAC transgene approaches have less integration position effects and dosage artifacts when compared with traditional transgenic approaches. Also, a BAC can achieve the same tissue‐specific expression as a knock‐in of the same gene with less effort and shorter time of establishment. The λ‐RED recombinogenic system has been used to manipulate DNA constructs with site‐directed mutagenesis, truncation, and tagging with an epitope tag or as a fusion protein by homologous recombination, as well as used here to modify many BACs with various transgenes. The recombineering plasmid, pKD46, is used to fabricate BAC transgenic constructs that can be used in generating transgenic organisms as well as used in mammalian cell culture. Curr. Protoc. Mol. Biol. 95:23.14.1‐23.14.28. © 2011 by John Wiley & Sons, Inc.
Setting Up and Running an Advanced Light Microscopy and Imaging Facility
Authors: Sánchez Carlos , Muñoz Ma Ángeles , Villalba Maite , Labrador Verónica , Díez‐Guerra F. Javier
Published: July 2011

During the last twenty years, interest in light microscopy and imaging techniques has grown in various fields, such as molecular and cellular biology, developmental biology, and neurobiology. In addition, the number of scientific articles and journals using these techniques is rapidly increasing. Nowadays, most research institutions require sophisticated microscopy systems to cover their investigation demands. In general, such instruments are too expensive and complex to be purchased and managed by a single laboratory or research group, so they have to be shared with other groups and supervised by specialized personnel. This is the reason why microscopy and imaging facilities are becoming so important at research institutions nowadays. In this unit, we have gathered and presented a number of issues and considerations from our own experience that we hope will be helpful when planning or setting up a new facility. Curr. Protoc. Cytom. 57:12.22.1‐12.22.21. © 2011 by John Wiley & Sons, Inc.
Photoactivation and Imaging of Optical Highlighter Fluorescent Proteins
Authors: Patterson George H.
Published: July 2011

A major advance in the microscopic study of cells and tissues is the introduction of photoactivatable fluorescent proteins, which can specifically mark proteins of interest within a living cell. Fluorescent proteins are now available that allow a pool of molecules to be “turned on” by photoactivation. This unit discusses technical aspects for the general use of photoactivatable fluorescent proteins and introduces some specific applications in the concluding remarks. Curr. Protoc. Cytom. 57:12.23.1‐12.23.12. © 2011 by John Wiley & Sons, Inc.
Circumpolar adaptation, social change, and the development of autoimmune thyroid disorders among the Yakut (Sakha) of Siberia
Authors: Cepon Tara J. , Snodgrass J. Josh , Leonard William R. , Tarskaia Larissa A. , Klimova Tatiana M. , Fedorova Valentina I. , Baltakhinova Marina E. , Krivoshapkin Vadim G.
Published: July 2011

Objectives:

Alterations in thyroid function appear to play a central role in adaptation to Arctic environments. Increased thyroid activity in indigenous circumpolar populations is associated with upregulated metabolism, including elevated basal metabolic rate (BMR); however, little is known about the possible health consequences of these climate‐induced changes on thyroid function. The focus of the present study is to determine the prevalence of autoimmune thyroid disorders and their lifestyle and metabolic correlates among a sample of indigenous Yakut adults from northeastern Siberia.

Methods:

Anthropometric dimensions, health data, and plasma samples were collected among 281 adults (143 women, 138 men; ≥18 years old) from the rural community of Berdygestiakh (62°N, 127°E; pop. 4,900), Sakha Republic (Yakutia), Russia. BMR measurements were available for 96 women and 98 men. Free triiodothyronine (T3), free thyroxine (T4), thyroid stimulating hormone (TSH), and anti‐thyroid peroxidase antibody (TPOAb) levels were determined using enzyme immunoassay.

Results:

Twenty‐two percent of women and 6% of men had clinically elevated (>30 IU/ml) TPOAb. TPOAb was positively correlated with TSH (P < 0.01), T3 (P < 0.05), and T4 (P < 0.05) in women and showed a positive trend with T4 (P = 0.06) in men. Monthly household income was significantly positively correlated with TPOAb in men (P < 0.01) and showed a trend among women (P = 0.06).

Conclusions:

Although preliminary, these findings document higher than expected TPOAb levels among Yakut women and suggest possible consequences of increased thyroid activity associated with circumpolar adaptation and social change. Am. J. Hum. Biol. 2011. © 2011 Wiley‐Liss, Inc.
Modeling neolithic dispersal in Central Europe: Demographic implications
Authors: Galeta Patrik , Sládek Vladimír , Sosna Daniel , Bruzek Jaroslav
Published: July 2011

On the basis of new examination of ancient DNA and craniometric analyses, Neolithic dispersal in Central Europe has been recently explained as reflecting colonization or at least a major influx of near eastern farmers. Given the fact that Neolithic dispersal in Central Europe was very rapid and extended into a large area, colonization would have to be associated with high population growth and fertility rates of an expanding Neolithic population. We built three demographic models to test whether the growth and fertility rates of Neolithic farmers were high enough to allow them to colonize Central Europe without admixture with foragers. The principle of the models is based on stochastic population projections. Our results demonstrate that colonization is an unlikely explanation for the Neolithic dispersal in Central Europe, as the majority of fertility and growth rate estimates obtained in all three models are higher than levels expected in the early Neolithic population. On the basis of our models, we derived that colonization would be possible only if (1) more than 37% of women survived to mean age at childbearing, (2) Neolithic expansion in Central Europe lasted more than 150 years, and (3) the population of farmers grew in the entire settled area. These settings, however, represent very favorable demographic conditions that seem unlikely given current archaeological and demographic evidence. Therefore, our results support the view that Neolithic dispersal in Central Europe involved admixture of expanding farmers with local foragers. We estimate that the admixture contribution from foragers may have been between 55% and 72%. Am J Phys Anthropol, 2011. © 2011 Wiley‐Liss, Inc.
Graphen: Materialien im Flachland (Nobel‐ Aufsatz)
Authors: Novoselov Kostya S.
Published: July 2011

Gleich der Welt von Abbotts “Flächenland” ist auch die Welt von Graphen eine zweidimensionale. Und ebenso wie “Flächenland” ein “Märchen mit vielerlei Dimensionen” ist, ist auch Graphen viel mehr als nur ein flacher Kristall. Graphen hat eine Vielzahl ungewöhnlicher Eigenschaften, die oftmals einzigartig oder denen von anderen Materialien überlegen sind. In diesem Aufsatz möchte ich erläutern, warum ich (und viele andere) mich davon so sehr habe faszinieren lassen, und den Leser dazu einladen, meine Begeisterung bei der Erforschung dieses Materials mitzuerleben.
Graphene: Materials in the Flatland (Nobel Lecture)
Authors: Novoselov Kostya S.
Published: July 2011

Much like the world described in Abbott’s “Flatland”, graphene is a two‐dimensional object. And, as “Flatland” is “A Romance of Many Dimensions”, graphene is much more than just a flat crystal. It possesses a number of unusual properties which are often unique or superior to those in other materials. In this brief lecture I would like to explain the reason for my (and many other people’s) fascination with this material, and invite the reader to share some of the excitement I’ve experienced while researching it.
Repetitive controller design for optimal performance
Authors: Chen Wentao , Lin Yechun
Published: July 2011

In this paper, a repetitive controller design method is proposed for optimal performance. Firstly, to compensate for phase lag introduced by the low‐pass filter in the scheme, the dead time of the repetitive controller is modified. Secondly, a lead compensator is introduced to the repetitive controller, which not only widens the bandwidth of the low‐pass filter, but also improves system gain at high frequencies. The optimal parameters of the repetitive controller are obtained by solving two optimization problems. A numerical example is provided to illustrate the validity of the proposed method.

Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Verbesserte Bemessungsrichtlinien für Bewehrte Elastomerlager
Authors: Gerharer Ulrich , Strauss Alfred , Bergmeister Konrad
Published: July 2011

Der Aufsatz stellt eine Zusammenfassung der im Rahmen eines FWF‐Projekts (Fonds zur Förderung der wissenschaftlichen Forschung in Österreich) erarbeiteten Verbesserung der Bemessungsrichtlinien für bewehrte Elastomerlager dar. Die Untersuchungen sind eine Reaktion auf die Defizite der derzeitigen Normenlage für statisch und dynamisch beanspruchte Elastomerlager im Bauwesen. Die in den Normen getroffenen Vereinfachungen sowie die Widersprüche zwischen den Normen [1] und [2] werden hinterfragt. Darüber hinaus wird die Diskrepanz zwischen den vereinfachten Bemessungsansätzen und dem komplexen mechanischen Verhalten von Elastomerlagern thematisiert.

Advanced Design Guidelines for Fiber Reinforced Elastomeric Bearings. This paper represents the summary of the development of advanced design guidelines for elastomeric bearings acquired in the course of a FWF project. This research is a reaction on the deficits of the current design codes for statically and dynamically loaded elastomeric bearings. Simplifications and contradictions of the design codes [1] and [2] are discussed. Furthermore the discrepancy between the simplified analytical formulations and the complex bearing behavior is described.
Verfahren für Biegeverstärkungen an Stahlbetonbauteilen
Authors: Jesse Frank , Kaplan Felix
Published: July 2011

Im Falle nicht ausreichender Tragfähigkeit eines Stahlbetonbauteils liegt die Entscheidung für eine Verstärkung oder einen Ersatz beim Tragwerksplaner. In aller Regel kommen mehrere Möglichkeiten in Betracht, darunter auch verschiedene Verfahren der Ertüchtigung der Zugzone. Der Beitrag stellt den aktuellen Stand der Technik der Verstärkungsverfahren (Spritzbeton, geklebte Carbonfaserkunststoffe und Textilbeton) für Verstärkungen der Zugzone von Biegebauteilen gegenüber, erläutert die charakteristischen Eigenschaften und Anwendungsbereiche und fasst die wesent lichen Kriterien in einer einfach handhabbaren Entscheidungsmatrix zusammen, um den Ingenieur bei der Entscheidungsfindung zu unterstützen.

Methods for flexural strengthening of RC members. In case of insufficient capacity of an RC structural member the decision making on strengthening or replacement is up to the design engineer. Generally, several options are taken into consideration, among others also different techniques for tension zone strengthening. This paper gives an overview on state of the art tension zone strengthening techniques with non prestressed reinforcement for bending members. Typical properties and application areas are characterised and essential criterions are summarised in a simple to handle decision matrix to support design engineers decision making process.
Bahrmühlenviadukt — Erhaltung und Ertüchtigung der 15‐Bogen‐Natursteinbrücke an der Strecke Neukieritzsch—Chemnitz
Authors: Hering Elke , Bösche Thomas , Burkhardt Rüdiger
Published: July 2011

In den Jahren 2007 bis 2010 wurden durch die Deutsche Bahn AG anspruchsvolle Instandsetzungs‐ und Ertüchtigungsmaßnahmen am Bahrmühlenviadukt bei Chemnitz ausgeführt. Erläutert werden die zur Qualitätssicherung wichtigen Planungsschritte am Beispiel der denkmalgeschützten Natursteinbogenbrücke. Beschrieben werden die Planungsziele und ausgewählte Ergebnisse der Bestands‐ und Bauwerkszustandsanalyse als wichtige Projektgrundlagen.

Das Projekt liefert einen überzeugenden Nachweis für die technische Eignung und Anpassungsfähigkeit von historischen Gewölbebogenbrücken an moderne Nutzungsanforderungen.
Tragsicherheit einer historischen Sandsteinbalustrade
Authors: Curbach Manfred , Hampel Torsten , Scheerer Silke , Liebau Henning
Published: July 2011

In diesem Bericht wird der Belastungstest an einer historischen Sandsteinbalustrade beschrieben. Die Balustrade ist Bestandteil einer Freitreppe, die für die öffentliche Nutzung freigegeben werden soll. Die statische Berechnung war in diesem Fall nicht ausreichend, da die Konstruktion nur in Teilen bekannt war. Mit dem In‐situ‐Test konnte aber experimentell eine ausreichende Sicherheit nachgewiesen werden.

Structural safety of a historic sandstone balustrade. In this report the load test on a historic sandstone balustrade is described. The balustrade is part of an outside staircase that should be opened for public use. The static proof in this case was not sufficient because the construction was known only in part. With the experimental in‐situ‐test could be demonstrated adequate security.
Isothermal titration calorimetry study of the polyelectrolyte complexation of xanthan and chitosan samples of different degree of polymerization
Authors: Maurstad Gjertrud , Kitamura Shinichi , Stokke Bjørn T.
Published: July 2011

Mixing oppositely charged polyelectrolytes in aqueous solutions leads to the spontaneous formation of polyelectrolyte complexes. Here, we characterize the interaction between xanthan of two different chain lengths, a tri‐glucosamine and a chitosan polymer by isothermal titration calorimetry (ITC). Analysis of the experimental thermodynamic data assuming a single set of identical sites indicated both enthalpic and entropic contributions to the overall interaction in the interaction between xanthan and tri‐glucosamine. The relative contribution of entropy compared to enthalpy was found to be largest for the shortest chain length of xanthan. Using a chitosan polymer instead of tri‐glucosamine gave rise to two different stages in the interaction process. A model where the first stage of the ITC curve represent an initial polyelectrolyte complexation stage followed by aggregation on further titration of chitosan to the xanthan is suggested. Ultrastructure images by applying atomic force microscopy at some selected extents of titration are consistent with the two‐stage interpretation of the thermodynamic data. © 2011 Wiley Periodicals, Inc. Biopolymers 97: 1–10, 2012.
Optimization of flowrate for expansion of human embryonic stem cells in perfusion microbioreactors
Authors: Titmarsh Drew , Hidalgo Alejandro , Turner Jennifer , Wolvetang Ernst , Cooper‐White Justin
Published: July 2011

Microfluidic systems create significant opportunities to establish highly controlled microenvironmental conditions for screening pluripotent stem cell fate. However, since cell fate is crucially dependent on this microenvironment, it remains unclear as to whether continual perfusion of culture medium supports pluripotent stem cell maintenance in feeder‐free, chemically defined conditions, and further, whether optimum perfusion conditions exist for subsequent use of human embryonic stem cell (hESCs) in other microfludic systems. To investigate this, we designed microbioreactors based on resistive flow to screen hESCs under a linear range of flowrates. We report that at low rates (conditions where glucose transport is convection‐limited with Péclet number <1), cells are affected by apparent nutrient depletion and waste accumulation, evidenced by reduced cell expansion and altered morphology. At higher rates, cells are spontaneously washed out, and display morphological changes which may be indicative of early‐stage differentiation. However, between these thresholds exists a narrow range of flowrates in which hESCs expand comparably to the equivalent static culture system, with regular morphology and maintenance of the pluripotency marker TG30 in >95% of cells over 7 days. For MEL1 hESCs the optimum flowrate also coincided with the time‐averaged medium exchange rate in static cultures, which may therefore provide a good first estimate of appropriate perfusion rates. Overall, we demonstrate hESCs can be maintained in microbioreactors under continual flow for up to 7 days, a critical outcome for the future development of microbioreactor‐based screening systems and assays for hESC culture. Biotechnol. Bioeng. 2011;108: 2894–2904. © 2011 Crown in the right of Canada.
Optimized Biocatalytically Active Static Emulsions for Organic Synthesis in Nonaqueous Media
Authors: Wu Changzhu , Kraume Matthias , Ansorge‐Schumacher Marion B.
Published: July 2011

Literature reports biocatalytically active static emulsions (BASE) as promising systems for the preparation of biocatalysts designed for synthetic use in organic media. Their excellent catalytic performance is attributed to the numerous micropools of dissolved enzymes independently dispersed in silicone beads. Here, a systematic study of the structure and morphology of BASE and optimization in terms of bead size distribution and overall catalytic performance is presented. The study relies on beads obtained by using a novel preparation method that enables a considerably improved reproducibility of the particle size and catalytic activity in separate batches. A large interfacial area of 0.023 m2 g−1 material was calculated. The adjustment of bead composition increased the apparent catalytic activity of entrapped lipase A from Candida antarctica (CalA) to 0.71 U gBASE−1, which is almost twofold higher than that previously reported. The specific activity remained in the range of prototype BASE (0.21 U mgprotein−1), which nevertheless is about 53 times higher than that reported for CalA entrapped in a sol–gel.
Cubic and Hexagonal Mesoporous Carbon in the Pores of Anodic Alumina Membranes
Authors: Schuster Jörg , Keilbach Andreas , Köhn Ralf , Döblinger Markus , Dörfler Thilo , Dennenwaldt Teresa , Bein Thomas
Published: July 2011

Cubic and circular hexagonal mesoporous carbon phases in the confined environment of the pores of anodic alumina membranes (AAM) were obtained by organic–organic self‐assembly of a preformed oligomeric resol precursor and the triblock copolymer templates Pluronic F127 or P123, respectively. Casting and solvent evaporation were followed by self‐assembly and the formation of a condensed wall material by thermopolymerization of the precursor oligomers, thus resulting in mesostructured phenolic resin phases. Subsequent thermal decomposition of the surfactant and carbonization were achieved through thermal treatment at temperatures up to 1000 °C under an inert atmosphere. The resulting hierarchical mesoporous composite materials were characterized by small‐angle X‐ray scattering and nitrogen‐sorption measurements. The structural features were directly imaged in TEM cross‐sections of the composite membranes. For both structures, the AAM pores were completely filled and no shrinkage was observed due to strong adhesion of the carbon‐wall material to the AAM pore walls. As a consequence, the pore size of the mesophase system stays almost constant even after thermal treatment at 1000 °C.
Self‐Assembly of Supramolecular Architectures and Polymers by Orthogonal Metal Complexation and Hydrogen‐Bonding Motifs
Authors: Grimm Felix , Ulm Nadine , Gröhn Franziska , Düring Jasmin , Hirsch Andreas
Published: July 2011

A modular construction kit with two orthogonal noncovalent binding sites for self‐assembly of supramolecular architectures is presented. The heteroditopic building blocks contain a terpyridine (tpy) unit for coordination of metal ions and a Hamilton receptor for multiple H‐bonding of cyanuric acid derivatives. The association constants of ligand binding of MII complexes (M=Ru, Zn, Fe, and Pt) with a dendritic end cap were determined to be in the range of 102 and 104 L mol−1 in chloroform. The capabilities for binding of metal ions were investigated by 1H NMR and UV/Vis spectroscopy. The Fe complexes are most appropriate for the generation of discrete and high‐ordered architectures due to their strong tendency to form FeL2 complexes. Superstructures are readily formed in a one‐pot procedure at room temperature. No mutual interactions between the orthogonal binding motifs were observed, and this demonstrates the highly specific nature of each binding process. Decomplexation experiments were carried out to examine the reversibility of Fe–tpy coordination. Substitution of the terminal end cap with a homoditopic bis‐cyanurate linkage leads to formation of an iron‐containing supramolecular strand. Formation of coordination polymers was confirmed by viscosity measurements. The supramolecular polymer strands can be reversibly cleaved by addition of a terminating cyanuric acid building block, and this proves the dynamic nature of this noncovalent polymerization process.
The Role of Electronic Coupling in Linear Porphyrin Arrays Probed by Single‐Molecule Fluorescence Spectroscopy
Authors: Yang Jaesung , Lee Ji‐Eun , Lee Chang Yeon , Aratani Naoki , Osuka Atsuhiro , Hupp Joseph T. , Kim Dongho
Published: July 2011

Single‐molecule photophysical properties of two families of linear porphyrin arrays have been investigated by single‐molecule fluorescence detection techniques. Butadiyne‐linked arrays (ZNB) with extensive π‐conjugation perform as photostable one‐quantum systems. This demonstration has been suggested by the long‐lasting initial emissive state and subsequent discrete one‐step photobleaching in the fluorescence intensity trajectories (FITs). As in the behavior of a one‐quantum system, ZNB shows anti‐bunching data in the coincidence measurements. On the other hand, in directly‐linked arrays (ZN) with strong dipole coupling, each porphyrin moiety keeps individual character in photobleaching dynamics. The stepwise photobleachings in the FITs account for this explanation. Most of the FITs of ZN do not carry momentary cessation of fluorescence emission, which has been explained by the strongly bound electron‐hole pair of Frenkel exciton that suppresses charge transfer between the molecule and surrounding polymers. These results give insight into the influences of interchromophorinc interactions between porphyrin moieties in the multiporphyrin arrays on their fluorescence dynamics at the single‐molecule level.
Intramolecular Weak Interactions in the Thermodynamic Stereoselectivity of Copper(II) Complexes with Carnosine–Trehalose Conjugates
Authors: Grasso Giuseppa I. , Arena Giuseppe , Bellia Francesco , Maccarrone Giuseppe , Parrinello Michele , Pietropaolo Adriana , Vecchio Graziella , Rizzarelli Enrico
Published: July 2011

The interactions of metal ions with chiral molecules are of particular interest for relevant biochemical processes, as many of them are made possible only with a selected chirality of the stereocenters. In this work we report a study of the stereoselectivity of copper(II) complexes with D‐trehalose–L‐carnosine and D‐trehalose–D‐carnosine as a prototypical case of natural chirality selection. The interest in L‐carnosine dipeptide is compounded by its antioxidant and antitumor properties, which are further enhanced when combined with D‐trehalose. Potentiometric, calorimetric, and UV/circular dichroism (CD) spectroscopic measurements show that the copper(II) dimer of D‐trehalose–L‐carnosine is more stable than the D‐trehalose–D‐carnosine diastereoisomeric copper(II) dimer (log ${\beta {{{l}\hfill \atop 22- 2\hfill}}}$−log ${\beta {{{d}\hfill \atop 22- 2\hfill}}}$=3.6). Free‐energy calculations highlight that the cause of this different behavior lies with different intramolecular weak interactions between the diastereoisomers. The different pattern of hydrogen bonds and the different CH–π interactions between the π‐electron‐rich imidazole and the α‐glucose rings are more favorable by 5 kcal mol−1 in the L dimer.
On the Reactions of Methyl Radicals with TiO2 Nanoparticles and Granular Powders Immersed in Aqueous Solutions
Authors: Golberg‐Oster Olga , Bar‐Ziv Ronen , Yardeni Guy , Zilbermann Israel , Meyerstein Dan
Published: July 2011

Methyl radicals react with TiO2 nanoparticles (NPs) immersed in aqueous solutions to form transients in which the methyls are covalently bound to the particles. The rate constant for this reaction approaches the diffusion‐controlled limit and increases somewhat with the number of methyls bound to the particle. The transients decompose to yield ethane. Thus, formally the particles “catalyse” the dimerization of the radicals, a reaction that is diffusion‐controlled. Rutile powders behave similarly to the TiO2 NPs whereas the mechanism for the decomposition of the transients formed in the analogous reaction of the radicals with anatase powders differs. These results are of importance as alkyl radicals are formed near the surface of TiO2 in a variety of important photocatalytic processes. The results imply that the reactions of alkyl radicals with TiO2 have to be considered in these processes.
Inelastic Neutron Scattering on an Mn10 Supertetrahedron: Assessment of Exchange Coupling Constants, Ferromagnetic Spin Waves and an Analogy to the Hückel Method
Authors: Stuiber Stefan , Wu Gang , Nehrkorn Joscha , Dreiser Jan , Lan Yanhua , Novitchi Ghenadie , Anson Christopher E. , Unruh Tobias , Powell Annie K. , Waldmann Oliver
Published: July 2011

The synthesis, crystal structure and magnetic characterisation by magnetisation and inelastic neutron scattering (INS) of a mixed‐valent Mn10 supertetrahedral aggregate [MnIII6MnII4(μ4‐O)4(μ3‐N3)3(μ3‐Br)(Hmpt)6(Br)]Br0.7(N3)0.3⋅2 MeOH⋅3 MeCN (1) (H3mpt=3‐methylpentan‐1,3,5‐triol) is reported. The magnetic core of the molecule can be described as an octahedron of six S=2 MnIII ions with four faces, each capped by a S=5/2 MnII ion such as to form the supertetrahedron. Unlike most related complexes, the molecular symmetry is slightly reduced from approximately Td to C3. The magnetic data reveal a total spin of S=22 in the ground state due to ferromagnetic exchange couplings within the molecule. The combined INS and magnetic data permits the accurate determination of the exchange coupling constants. Two types are found. The couplings between the MnIII ions in the inner octahedron are characterised by Ja=18.4(3) K, whereas the couplings between the apical MnII ions to the neighbouring MnIII ions are given by Jb=7.3(2) K. The significantly larger coupling strength Ja as compared to Jb, and the near‐Td symmetry have profound consequences on the energy spectrum, which are discussed and carefully analysed. In particular, the observed INS spectra can consistently be reproduced by a simplified model in which the inner octahedron is replaced by one large spin of length S0=12. This model provides intuitive insight into the structure of the magnetic spectrum. Additionally, the magnetic excitations at low temperature are analysed within the frame of ferromagnetic linear spin‐wave theory, which permits an analytical calculation of the energy levels. For ferromagnetic clusters, a close analogy to the Hückel method of electronic structure calculation can be drawn, which allows one to grasp the results of the spin‐wave theory or the magnetic excitation spectrum, respectively, in a chemical language.
Generating Hydrogen Gas from Methane with Carbon Captured as Pure Spheroidal Nanomaterials
Authors: Cornejo Andrew , Zhang Weike , Gao Lizhen , Varsani Rahi R. , Saunders Martin , Iyer K. Swaminathan , Raston Colin L. , Chua Hui Tong
Published: July 2011

Energy production by using hydrogen gas as a feedstock is considered to be one of the keys to creating clean energy, with the proviso that the gas is generated in a sustainable way with no emissions. A simple, self‐sustaining process generating hydrogen gas from methane using inexpensive stainless steel wire‐mesh catalysts at elevated temperatures (800 °C) is reported. A theoretical analysis of the production of electricity by this process revealed peak chain energy efficiencies up to 21 % (emission free) when using a percentage of the produced hydrogen (approximately 40 % of purified yield) as the heat source. In addition, a practical method has been developed to purify the carbon byproduct, affording essentially pure highly graphitic spheroidal carbon for advanced materials applications.
Chemical Surface Modification of Self‐Assembled Monolayers by Radical Nitroxide Exchange Reactions
Authors: Wagner Hendrik , Brinks Marion K. , Hirtz Michael , Schäfer Andreas , Chi Lifeng , Studer Armido
Published: July 2011

This article describes the application of nitroxide exchange reactions of surface‐bound alkoxyamines as a tool for reversible chemical modification of self‐assembled monolayers (SAMs). This approach is based on radical chemistry, which allows for introduction of various functional groups and can be used to reversibly introduce functionalities at surfaces. To investigate the scope of this surface chemistry, alkoxyamines with different functionalities were synthesized and were then applied to the immobilization of, for example, dyes, sugars, or biotin. Surface analysis was carried out by contact angle, X‐ray photoelectron spectroscopy, and fluorescence microscopy measurements. The results show that this reaction is highly efficient, reversible, and mild and allows for immobilization of various sensitive functional groups. In addition, Langmuir–Blodgett lithography was used to generate structured SAMs. Site‐selective immobilization of a fluorescent dye could be achieved by nitroxide exchange reactions.
Novel Multidentate Sulfur–Nitrogen Ligands with Enhanced Complexation Properties
Authors: Meinholz Margret M. , Klemmer Maika , Kriemen Ella , Stalke Dietmar
Published: July 2011

Di(tert‐butyl)sulfur diimide and bis(trimethylsilyl)sulfur diimide were reacted with different metalated amines to form versatile novel multidentate ligand systems with side‐arm donation. Their complexation properties in terms of ligand design, denticity and the cation size are discussed. We report herein the synthesis and structure elucidation of [(tBuN)2S{LiMe2N(C6H4)S(NtBu)2}2] (1), [(Li{Me2N(C6H4)S(NSiMe3)2})2] (2), [(Li(thf){Me2N(C6H4)S(NSiMe3)2})2] (3), [(Li{2‐PicS(NSiMe3)2})2] (4), [(Li{Me2N(CH2)2N(Me)S(NSiMe3)2})2] (5), [(Na{Me2N(CH2)2N(Me)S(NSiMe3)2})2] (6) and [(K{Me2N(C6H4)S(NSiMe3)2})2] (7).
An Axially Chiral, Electron‐Deficient Borane: Synthesis, Coordination Chemistry, Lewis Acidity, and Reactivity
Authors: Mewald Marius , Fröhlich Roland , Oestreich Martin
Published: July 2011

An axially chiral dihydroborepine with a binaphthyl backbone and a C6F5 substituent at the boron atom was prepared by transmetalation from the corresponding tin precursor. This novel motif was structurally characterized by X‐ray diffraction analysis as its THF and its PhCN Lewis acid/base complex. 1H NMR measurements at variable temperatures of the former adduct revealed a remarkable dynamic behavior in solution. Several more Lewis pairs with oxygen, nitrogen, carbon, and phosphorus σ‐donors were synthesized and analyzed by multinuclear NMR spectroscopy. The determination of the borane’s Lewis acidity with the Gutmann–Beckett method attests its substantial Lewis acidity [85 % with Et3PO as well as 74 % with Ph3PO relative to the parent B(C6F5)3]. Representative examples of SiH bond activation (carbonyl reduction and dehydrogenative SiO coupling) are included, demonstrating the chemical stability and the synthetic potential of the new chiral boron‐based Lewis acid.
Synthetic Utilization of 2‐Chloro‐1,1,1,2‐tetrafluoroethane
Authors: Notsu Keiji , Zushi Yasuyuki , Ota Shin , Kawasaki‐Takasuka Tomoko , Yamazaki Takashi
Published: July 2011

β‐Substituted α‐fluoro‐α,β‐unsaturated carboxylic acids have been successfully synthesized, usually in a (Z)‐stereospecific manner by way of a stepwise or a one‐pot three‐step procedure starting from 2‐chloro‐1,1,1,2‐tetrafluoroethane (HCFC‐124), one of the major byproducts of the industrial process for tetrafluoroethene formation from chlorofluoromethane (HCFC‐22).
Ruthenium‐Catalysed Synthesis of Fluorinated Bicyclic Amino Esters through Tandem Carbene Addition/Cyclopropanation of Enynes
Authors: Eckert Matthieu , Moulin Solenne , Monnier Florian , Titanyuk Igor D. , Osipov Sergey N. , Roisnel Thierry , Dérien Sylvie , Dixneuf Pierre H.
Published: July 2011

The reaction of fluorinated 1,6‐ and 1,7‐enynes, containing the moiety N(PG)C(CF3)(CO2R), with diazo compounds in the presence of [RuCl(cod)(Cp*)] (cod=cycloocta‐1,5‐diene, Cp*=C5Me5, PG=protecting group) as the catalyst precursor leads to the formation of fluorinated 3‐azabicyclo[3.1.0]hexane‐2‐carboxylates and 4‐azabicyclo‐[4.1.0]heptane‐3‐carboxylates. This catalytic transformation was applied to various protecting groups and has proved to be a selective and a general synthetic tool to form constrained proline or homoproline derivatives in good yields. Z stereoselectivity of the created alkenyl group is obtained with N2CHSiMe3, whereas N2CHCO2Et favours selectively the E configuration for the same double bond. The diastereoselectivity exo/endo depends on the size of the created ring. The X‐ray structures of two products have been determined, showing the stereochemistry of the compounds. The reaction can be understood by initial [2+2] addition of the RuCHY bond, generated from diazoalkane, with the CCH bond of the enyne leading to a key bicyclic ruthenacyclobutane, which promotes the cyclopropanation, rather than metathesis. This selective formation of bicyclic [n.1.0] compounds results from the ruthenium‐catalysed creation of three carbon–carbon bonds in a single step under mild conditions.
The Organocatalytic Vinylogous Aldol Reaction: Recent Advances
Authors: Pansare Sunil V. , Paul Eldho K.
Published: July 2011

Over the past decade, organocatalysis has emerged as a powerful tool for stereoselective carbon–carbon bond formation under exceptionally mild conditions. The organocatalytic versions of a large number of traditional synthetic transformations are now well established and the quest for new applications of the basic concepts of organocatalysis continues. This review addresses the emergent interest in the organocatalytic vinylogous aldol reaction. While noteworthy progress has been made in this area, significant challenges lie ahead.
Identification of a Glycogen Synthase Kinase‐3β Inhibitor that Attenuates Hyperactivity in CLOCK Mutant Mice
Authors: Kozikowski Alan P. , Gunosewoyo Hendra , Guo Songpo , Gaisina Irina N. , Walter Richard L. , Ketcherside Ariel , McClung Colleen A. , Mesecar Andrew D. , Caldarone Barbara
Published: July 2011

Bipolar disorder is characterized by a cycle of mania and depression, which affects approximately 5 million people in the United States. Current treatment regimes include the so‐called “mood‐stabilizing drugs”, such as lithium and valproate that are relatively dated drugs with various known side effects. Glycogen synthase kinase‐3β (GSK‐3β) plays a central role in regulating circadian rhythms, and lithium is known to be a direct inhibitor of GSK‐3β. We designed a series of second generation benzofuran‐3‐yl‐(indol‐3‐yl)maleimides containing a piperidine ring that possess IC50 values in the range of 4 to 680 nM against human GSK‐3β. One of these compounds exhibits reasonable kinase selectivity and promising preliminary absorption, distribution, metabolism, and excretion (ADME) data. The administration of this compound at doses of 10 to 25 mg kg−1 resulted in the attenuation of hyperactivity in amphetamine/chlordiazepoxide‐induced manic‐like mice together with enhancement of prepulse inhibition, similar to the effects found for valproate (400 mg kg−1) and the antipsychotic haloperidol (1 mg kg−1). We also tested this compound in mice carrying a mutation in the central transcriptional activator of molecular rhythms, the CLOCK gene, and found that the same compound attenuates locomotor hyperactivity in response to novelty. This study further demonstrates the use of inhibitors of GSK‐3β in the treatment of manic episodes of bipolar/mood disorders, thus further validating GSK‐3β as a relevant therapeutic target in the identification of new therapies for bipolar patients.
Synthesis of Aryl‐Substituted Naphthalene‐Linked Pyrrolobenzodiazepine Conjugates as Potential Anticancer Agents with Apoptosis‐Inducing Ability
Authors: Kamal Ahmed , Reddy M. Kashi , Ramaiah M. Janaki , Srikanth Y. V. V. , Rajender  , Reddy V. Santosh , Kumar G. Bharath , Pushpavalli S. N. C. V. L. , Bag Indira , Juvekar Aarti , Sen Subrata , Zingde Surekha M. , Pal‐Bhadra Manika
Published: July 2011

A library of new aryl‐substituted naphthalene C8‐linked pyrrolo[2,1‐c][1,4]benzodiazepine (PBD) conjugates with various linker architectures were designed, synthesized, and evaluated for their anticancer activity against a panel of 11 human cancer cell lines. All 32 conjugates show anticancer potential, with some of them exhibiting particularly high activity (0.01–0.19 μM). Thermal denaturation studies showed effective DNA binding capacity relative to DC‐81. In assays for biological activity relating to cell‐cycle distribution, these PBD conjugates induce G0/G1‐phase arrest and also cause an increase in the levels of p53 and caspase‐9 proteins, followed by apoptotic cell death. One conjugate in particular is the most promising candidate of the series, with the potential to be selected for further studies, either alone or in combination with existing anticancer therapies.
Use of human papillomavirus vaccines among young adult women in the United States: An analysis of the 2008 National Health Interview Survey
Authors: Anhang Price Rebecca , Tiro Jasmin A. , Saraiya Mona , Meissner Helen , Breen Nancy
Published: July 2011

BACKGROUND:

The Centers for Disease Control and Prevention recommends catch‐up administration of human papillomavirus (HPV) vaccines to girls and women ages 13 to 26 who have not been vaccinated previously. In response to debate regarding catch‐up vaccination of young adult women, this study examined whether 18‐ to 26‐year‐old women most likely to benefit from catch‐up vaccination were aware of the HPV vaccine, and initiated the vaccine series by the end of 2008.

METHODS:

We used data from the 2008 National Health Interview Survey to assess HPV vaccine awareness and use, and reasons for not vaccinating, among women aged 18‐26 years (n = 1583). Sociodemographic, health care access, and health history factors associated with vaccine initiation were assessed using multivariate logistic regression.

RESULTS:

Overall, 11.7% of women aged 18‐26 years reported receiving at least 1 dose of the HPV vaccine by the end of 2008. In multivariate analyses, younger age, history of previous HPV infection, unmarried status, health insurance, flu shot in the past year, and receipt of 1 or more recommended lifetime vaccines were significantly associated with HPV vaccine initiation. Two‐fifths (39.6%) of unvaccinated women were interested in receiving the HPV vaccine (n = 1327). Primary reasons for lack of interest in the vaccine were belief that it was not needed, not knowing enough about it, concerns about safety, and not being sexually active.

CONCLUSION:

HPV vaccine coverage among young adult women was low, and lower among the uninsured than the insured. Public financing and care provision programs have the potential to expand vaccine coverage among uninsured women, who are at increased risk of cervical cancer. Cancer 2011;. © 2011 American Cancer Society.
Clinically significant Gleason sum upgrade
Authors: Iremashvili Viacheslav , Manoharan Murugesan , Pelaez Liset , Rosenberg Daniel L. , Soloway Mark S.
Published: July 2011

BACKGROUND:

Several nomograms have been developed for the purpose of predicting the likelihood of an increase in Gleason sum (GS) from biopsy information compared with the GS determined after examination of the “entire prostate” in patients with prostate cancer. In this study, the authors evaluated and compared the ability of 4 nomograms (published by Capitanio et al, Chun et al, Kulkarni et al, and Moussa et al) to predict GS upgrades for patients with biopsy GS ≤6 prostate cancer who underwent radical prostatectomy (RP) at their center.

METHODS:

The entire study cohort included 942 patients with a biopsy GS ≤6. Predictive performances of the nomograms were compared using area under the receiver operating characteristic curve (AUC‐ROC) analysis, calibration plots, and decision curve analysis (DCA) in the entire cohort, in patients with low‐risk prostate cancer (LRPC), and a subgroup of those patients who underwent extended biopsy with ≥10 cores.

RESULTS:

Patients with a GS ≥7 at prostatectomy included 319 of 942 patients (33.9%) in the entire study cohort, 263 of 814 patients (32.2%) with LRPC, and 84 of 301 patients (27.9%) with LRPC who underwent extended biopsy. With an AUC‐ROC of 0.637 to 0.647 in the different subgroups of patients with low‐risk cancer, the Kulkarni et al nomogram demonstrated significantly higher discriminative ability compared with the other nomograms. The same nomogram provided a small clinical benefit at DCA. All nomograms were poorly calibrated.

CONCLUSIONS:

The available prognostic tools had limited ability to predict clinically significant upgrading in patients with biopsy GS ≤6 and, thus, the authors concluded that these tools are not ready for clinical application. Cancer 2011;. © 2011 American Cancer Society.
Use of the monoclonal antibody MOC‐31 as an immunomarker for detecting metastatic adenocarcinoma in effusion cytology
Authors: Kundu Uma R. , Krishnamurthy Savitri
Published: July 2011

BACKGROUND:

MOC‐31 is an established immunologic marker with which to detect adenocarcinomas. The objective of the current study was to evaluate the use of MOC‐31 in the diagnosis of metastatic adenocarcinoma in effusion specimens.

METHODS:

The authors evaluated cytologic specimens of effusions/washings in which MOC‐31 immunostaining was performed on unstained cell block sections or Papanicolaou‐stained cytospin preparations. Membranous staining with or without cytoplasmic staining was considered to be positive. The immunostaining results were correlated with the cytologic diagnoses and clinical follow‐up data.

RESULTS:

A total of 215 effusions and washings were identified (cell blocks in 162 cases, cytospin preparations in 53 cases, and both in 2 cases in which MOC‐31 immunostaining was performed). A total of 94 (44%) of the 215 cases were found to be positive for malignancy, including 87 metastatic adenocarcinomas. Specimens were positive for MOC‐31 in 76 (87%; 55 cell blocks and 21 cytospin preparations) of 87 cases of metastatic adenocarcinoma. Eleven cases of metastatic adenocarcinoma were found to be negative for MOC‐31 (4 cases from lung tumors, 2 from stomach tumors, 2 from colon tumors, 2 from breast tumors, and 1 from a renal tumor). Minimal and/or focal cytoplasmic staining for MOC‐31 was noted in 13% of cases of reactive mesothelial cells/mesothelioma. The sensitivity of MOC‐31 for metastatic adenocarcinoma was 89%, the specificity was 100%, the negative predictive value was 92%, and the positive predictive value was 100%.

CONCLUSIONS:

MOC‐31 alone was found to be highly sensitive for distinguishing reactive mesothelial cells/mesothelioma from metastatic adenocarcinoma in effusion specimens. Interpreting membranous MOC‐31 staining as positive can help prevent confusion between reactive mesothelial cells/mesothelioma and metastatic adenocarcinoma. Cancer (Cancer Cytopathol) 2011;. © 2011 American Cancer Society