bluuebunny/crossref_metadata_2025 huggingface dataset:
Selenium and Tellurium Derivatives of Carbohydrates and Nucleotides
Authors: Maciaszek Anna , Tomaszewska Agnieszka , Guga Piotr
Published: April 2014

Sugars, nucleosides, nucleotides and oligonucleotides labeled with a selenium atom in a sugar moiety, in a heterocyclic base, or within an internucleotide bond are synthesized, mostly, as analogs of naturally occurring biomolecules to be used in structural studies by means of X‐ray crystallography. Typically, selenium is substituted for an oxygen atom already present in the parent molecule, but labeling in non‐oxygen centers is also possible. Although in the synthesis of nucleosides introducing the chalcogen label can be done at any stage (i.e. before or after the glycosidic bond is formed), methods for conversion of natural nucleosides into the seleno derivatives are very useful, and are further used for synthesis of monomers suitable for synthesis of labeled oligonucleotides on a solid support. Interestingly, many types of selenium‐labeled oligonucleotides can form with DNA or RNA templates the higher order structures (e.g. duplexes, triplexes) of thermodynamic stability comparable to those formed by unmodified oligomers. Similar research, although less intense, is carried on with tellurium‐labeled biomolecules. The electronic and atomic properties of tellurium make this element excellent for labeling of biomolecules for X‐ray analysis. Unfortunately, strong metallic properties of tellurium result in weak covalent bonds with carbon and hydrogen. As a result, the telluro derivatives are much less stable compared to seleno compounds, and their purification and usage is more arduous.
Electrochemical Investigations of Organogold Compounds
Authors: Jaworski Jan S.
Published: April 2014

In the first part of the chapter measurements of molar conductivity of title compounds in solutions are reviewed. Such measurements performed under standard conditions, mainly in acetone solutions, were usually used to indicate the type of the electrolyte and the ionic character of the newly synthesized organogold compounds in order to support their structure.

The discussion of oxidation and reduction potentials determined mainly by the cyclic voltammetric method for different classes of organogold compounds, including mononuclear, binuclear and polynuclear gold derivatives, is presented in the second part of the chapter. The effects of the gold oxidation state, molecular structure, interactions between metal and organic moiety as well as between organic ligands on the stability of investigated compounds are mainly considered, as in original papers. However, mechanisms of electrode reactions are also mentioned in a few cases when they were investigated or postulated in original works.
Quantum chemical studies of carbonyl oxide chemistry in combustion and in the lower atmosphere
Authors: Kuwata Keith T.
Published: April 2014

Carbonyl oxides have multiple impacts on the atmosphere and on combustion. This review focuses on what electronic structure calculations, particularly those involvingab initiocomposite methods and density functional theory (DFT), have revealed about carbonyl oxide chemistry in combustion and atmospheric systems. Reliable electronic structure calculations consistently reveal that carbonyl oxides have little diradical character, which means that much of their chemistry can be modeled accurately by single‐reference methods. Computation predicts that carbonyl oxides form in the low‐temperature combustion of ethers, and, given that carbonyl oxides form hydroxyl radical (⋅OH), they likely contribute to chain branching. The atmospheric ozonolysis of acyclic alkenes leads to moderately chemically activated carbonyl oxides, making it necessary to treat both their unimolecular and bimolecular reactions. CCSD(T) calculations with triple‐zeta basis sets and CCSD(T)‐based composite methods can predict aspects of carbonyl oxide chemistry like the yield of⋅OH that agree with experiment, but the accuracy of these predictions also depend on statistical thermodynamic assumptions. DFT predictions regarding carbonyl oxide chemistry are often inaccurate. Recent experimental studies have corroborated the long‐standing quantum chemical prediction that carbonyl oxides with alkyl substituents eithersynorantito the peroxy bond have dramatically different unimolecular and bimolecular reactivity.
Computational Treatments of Peroxy Radicals in Combustion and Atmospheric Reactions
Authors: Kuwata Keith T.
Published: April 2014

Alkylperoxy radicals play critical roles in both combustion and in atmospheric chemistry. This review focuses on what electronic structure calculations, particularly those involvingab initiocomposite methods and density functional theory, have revealed about the mechanisms of important reactions in combustion and atmospheric systems. The formation of alkylperoxy radicals by addition of O2to alkyl radicals usually proceeds without an energy barrier, and the barriers that do exist often must be treated by multireference electronic structure methods to be predicted accurately. In contrast, peroxy radical well depths can be predicted accurately by single‐reference methods, provided that electron correlation is treated at the CCSD(T) or QCISD(T) level with basis sets containing multiple polarization functions. The composite CBS‐QB3 method does particularly well as judged against experimental measurements of carbon‐peroxy bond dissociation enthalpies. CBS‐QB3 also describes atmospheric reactions of alkylperoxy radicals with HO2more accurately than the B3LYP method of density functional theory. Finally, the same single‐reference methods that proved accurate for peroxy radical well depths can also be employed in accurate statistical rate theory models of the unimolecular reactions involved in low‐temperature combustion. Multiple variants of density functional theory have proven considerably less accurate in this regard.
Reactions of Peroxides on Solid Surfaces
Authors: Mello Rossella , González Núñez María Elena
Published: April 2014

This article describes the different roles that solid surfaces play in heterogeneous reactions involving peroxides, namely, (i) the solid surface interacts with the peroxide in the absence of any other substrate, (ii) the solid surface promotes the reaction activating either the peroxide or the substrate, (iii) the peroxide forms part of the solid active surface, and (iv) the substrate forms part of the active surface. The chapter covers reactions involving peroxides or discrete peroxydic transient species on solid surfaces or at solid–liquid and solid–gas interfaces, and provides general descriptions of different solid materials, details on reaction conditions, and synthetic procedures for solid‐supported reagents.
Nuclear Reactions
Authors: Bertulani Carlos A.
Published: April 2014

Nuclear reactions generate energy in nuclear reactors, in stars, and are responsible for the existence of all elements heavier than hydrogen in the Universe. Nuclear reactions denote reactions between nuclei, and between nuclei and other fundamental particles, such as electrons and photons. A short description of the conservation laws and the definition of basic physical quantities is presented, followed by a more detailed account of specific cases: (i) formation and decay of compound nuclei; (ii)direct reactions; (iii) photon and electron scattering; (iv) heavy ion collisions; (v) formation of a quark–gluon plasma; (vi) thermonuclear reactions; and (vii) reactions with radioactive beams. Whenever necessary, basic equations are introduced to help understand general properties of these reactions.
Neutrino Astrophysics
Authors: Haxton Wick C.
Published: April 2014

The field of neutrino astrophysics is reviewed, including basic neutrino properties, solar neutrinos (the standard solar model, helioseismology, and recent experimental results); neutrino mass, oscillations, and matter effects; atmospheric neutrinos; open questions in neutrino physics, such as the neutrino mass hierarchy,charge parity(CP) violation, and the absolute scale of neutrino masses; supernovae, including the explosion mechanism, the exotic matter effects that can influence neutrino propagation, and the neutrino role in energy transport and nucleosynthesis; neutrino cooling in red giants and connections to new neutrino properties such as magnetic moments; and high‐energy astrophysical neutrinos, their production in cosmic rays interactions and possible associations with cosmic‐ray point sources, and new high‐energy neutrino detectors such as IceCube.
Optics and Nuclear Photonics
Authors: Habs Dietrich
Published: April 2014

Our discovery that the scattering of γ quanta from the very large electric fields of nuclei, calledDelbrück scattering, results in a much larger real part of the index of refraction for γ‐rays than anticipated has manifold consequences. All older perturbativequantum electrodynamics(QED) predictions for a few million electronvolt γ‐rays by the first‐order Born approximation fail by many orders of magnitude and a new, more complex nonperturbative QED has to be applied. As the expected cross sections are now much larger, other nonperturbative high‐field QED effects such as photon splitting or an enhanced pair production close to the threshold are being investigated to study and understand this new high‐field QED with the ultrahigh electric fields of the nucleus. At the same time, the much larger Delbrück scattering allows to develop γ‐ray optics of up to about 10 MeV, with new focusing lenses and much more efficient γ monochromators. In combination with the development of much more intense, brilliant γ beams, this opens a new field of nuclear photonics. We, for the first time, will selectively excite individual nuclear levels for diagnostics of isotopes or their transmutation. The strongly penetrating γ beams focused to micrometer diameters open up new fields of diagnostics in medicine, green energy, nuclear waste management, and so on. We can produce about 50 new medical radioisotopes for cancer therapy or for the diagnostics of dose delivery to the tumor. Also, other brilliant secondary sources, such as cold neutron sources or moderated positron beams, can be produced, which open new ways for material or surface sciences.
Nuclear Astrophysics
Authors: Schatz Hendrik
Published: April 2014

Nuclear astrophysics aims at understanding the nuclear reaction processes that occur naturally in the cosmos and shape much of the visible universe. These nuclear processes make the stars shine, they power stellar explosions, and they are responsible for the origin of the elements, defining the relative proportions of elements available for life. This chapter highlights the direct connections between nuclear physics and astrophysics in a wide range of astrophysical environments and how the nuclear physics needed to understand the cosmos can be obtained from nuclear theory and nuclear physics experiments.
New MT‐ND6 and NDUFA1 mutations in mitochondrial respiratory chain disorders
Authors: Uehara Natsumi , Mori Masato , Tokuzawa Yoshimi , Mizuno Yosuke , Tamaru Shunsuke , Kohda Masakazu , Moriyama Yohsuke , Nakachi Yutaka , Matoba Nana , Sakai Tetsuro , Yamazaki Taro , Harashima Hiroko , Murayama Kei , Hattori Keisuke , Hayashi Jun‐Ichi , Yamagata Takanori , Fujita Yasunori , Ito Masafumi , Tanaka Masashi , Nibu Ken‐ichi , Ohtake Akira , Okazaki Yasushi
Published: April 2014

Objective

Mitochondrial respiratory chain disorder (MRCD) is an intractable disease of infants with variable clinical symptoms. Our goal was to identify the causative mutations in MRCD patients.

Methods

The subjects were 90 children diagnosed with MRCD by enzyme assay. We analyzed whole mitochondrial DNA (mtDNA) sequences. A cybrid study was performed in two patients. Whole exome sequencing was performed for one of these two patients whose mtDNA variant was confirmed as non‐pathogenic.

Results

Whole mtDNA sequences identified 29 mtDNA variants in 29 patients (13 were previously reported, the other 13 variants and three deletions were novel). The remaining 61 patients had no pathogenic mutations in their mtDNA. Of the 13 patients harboring unreported mtDNA variants, we excluded seven variants by manual curation. Of the remaining six variants, we selected two Leigh syndrome patients whose mitochondrial enzyme activity was decreased in their fibroblasts and performed a cybrid study. We confirmed that m.14439G>A (MT‐ND6) was pathogenic, while m.1356A>G (mitochondrial 12S rRNA) was shown to be a non‐pathogenic polymorphism. Exome sequencing and a complementation study of the latter patient identified a novel c.55C>T hemizygous missense mutation in the nuclear‐encoded gene NDUFA1.

Interpretation

Our results demonstrate that it is important to perform whole mtDNA sequencing rather than only typing reported mutations. Cybrid assays are also useful to diagnose the pathogenicity of mtDNA variants, and whole exome sequencing is a powerful tool to diagnose nuclear gene mutations as molecular diagnosis can provide a lead to appropriate genetic counseling.
Novel SiC/C Aerogels Through Pyrolysis of Polycarbosilane Precursors
Authors: Zera Emanuele , Campostrini Renzo , Aravind Parakkulam Ramaswamy , Blum Yigal , Sorarù Gian Domenico
Published: April 2014

A new approach for forming aerogels with various silicon‐based compositions and hybrids between ceramics and carbon has been developed by combining efficient hydrosilylation as the hybridization‐crosslinking approach associated with gelation in the presence of solvent and followed by supercritical drying techniques. Highly porous carbon‐enriched SiC/C aerogels with adequate mechanical durability have been synthesized, pyrolyzed, and characterized. The “wet” gels were obtained by crosslinking a commercial polycarbosilane with divinylbenzene via Pt‐catalyzed hydrosilylation reaction in highly diluted condition (90 vol% of solvent). A supercritical drying was performed after exchanging the solvent (cyclohexane) with liquid CO2 forming undamaged aerogels. A subsequent pyrolysis and heat treatment (up to 1500 °C) in argon flow converted the polymeric aerogel into a SiC/C‐based material with bulk density of 166 kg m−3, SSA of 444 m2 g−1, a micro‐meso pore volume of 0.79 cm3 g−1, total porosity above 90 vol% and ultimate compressive strength of 1.6 MPa. The final product was compared to its cured gel and intermediates obtained during the pyrolysis process.
Synergistic Computational‐Experimental Approach to Improve Ionene Polymer‐Based Functional Hydrogels
Authors: Bachl Jürgen , Zanuy David , López‐Pérez Daniel E. , Revilla‐López Guillermo , Cativiela Carlos , Alemán Carlos , Díaz David Díaz
Published: April 2014

The manifold applications of ionene‐based materials such as hydrogels in daily life, biomedical sciences, and industrial processes are a consequence of their unique physical and chemical properties, which are governed by a judicious balance between multiple non‐covalent interactions. However, one of the most critical aspects identified for a broader use of different polyelectrolytes is the need of raising their gelation efficiency. This work focuses on surfactant‐free ionene polymers 1−3 containing DABCO and N,N′‐(x‐phenylene)dibenzamide (x = ortho‐/meta‐/para‐) linkages as model systems to develop a combined computational‐experimental approach to improve the hydrogelation through a better understanding of the gelation mechanism. Molecular dynamics simulations of isomeric ionenes 1–3 with explicit water molecules point out remarkable differences in the assembly of the polymeric chains in each case. Interchain regions with high degree of hydration (i.e., polymer···water interactions) and zones dominated by polymer···polymer interactions are evident in the case of ortho‐ (1) and meta‐ (2) isomeric ionenes, whereas domains controlled by polymer···polymer interactions are practically inexistent in 3. In excellent agreement, ortho‐ionene 1 provides experimentally the best hydrogels with unique features such as thixotropic behavior and dispersion ability for single‐walles carbon nanotubes.
Digital Plasmonic Patterning for Localized Tuning of Hydrogel Stiffness
Authors: Hribar Kolin C. , Choi Yu Suk , Ondeck Matthew , Engler Adam J. , Chen Shaochen
Published: April 2014

The mechanical properties of the extracellular matrix (ECM) can dictate cell fate in biological systems. In tissue engineering, varying the stiffness of hydrogels—water‐swollen polymeric networks that act as ECM substrates—has previously been demonstrated to control cell migration, proliferation, and differentiation. Here, “digital plasmonic patterning” (DPP) is developed to mechanically alter a hydrogel encapsulated with gold nanorods using a near‐infrared laser, according to a digital (computer‐generated) pattern. DPP can provide orders of magnitude changes in stiffness, and can be tuned by laser intensity and speed of writing. In vitro cellular experiments using A7R5 smooth muscle cells confirm cell migration and alignment according to these patterns, making DPP a useful technique for mechanically patterning hydrogels for various biomedical applications.
Supramolecular Assembly of Metal‐Ligand Chromophores for Sensing and Phosphorescent OLED Applications
Authors: Wong Keith Man‐Chung , Chan Maggie Mei‐Yee , Yam Vivian Wing‐Wah
Published: April 2014

The exploration of phosphorescent materials based on transition metal‐ligand chromophoric complexes represents an important area of research in molecular materials. The knowledge and fundamental understanding of their photophysical properties offer a possible fine‐tuning of their electronic absorption and luminescence properties. The strong propensity of d8 transition metal compounds to form non‐covalent metal···metal interactions facilitates supramolecular assembly and the formation of supramolecular nanostructures with interesting photophysical properties. The introduction of supramolecular assembly with hierarchical complexity involving non‐covalent interactions could lead to research dimensions of unlimited possibilities and opportunities. This article briefly summarizes the latest progress on the use of d8 metal‐ligand chromophores as chemosensors, as exemplified by alkynylplatinum(II) complexes with emphasis on supramolecular assembly involving non‐covalent interactions, and the recent advances in the utilization of d8 metal‐ligand phosphors, as exemplified by alkynylgold(III) system, for the exploration and development of phosphorescent OLEDs.
Irreversible Denaturation of Proteins through Aluminum‐Induced Formation of Backbone Ring Structures
Authors: Song Bo , Sun Qian , Li Haikuo , Ge Baosheng , Pan Ji Sheng , Wee Andrew Thye Shen , Zhang Yong , Huang Shaohua , Zhou Ruhong , Gao Xingyu , Huang Fang , Fang Haiping
Published: April 2014

A combination of ab initio calculations, circular dichroism, nuclear magnetic resonance, and X‐ray photoelectron spectroscopy has shown that aluminum ions can induce the formation of backbone ring structures in a wide range of peptides, including neurodegenerative disease related motifs. These ring structures greatly destabilize the protein and result in irreversible denaturation. This behavior benefits from the ability of aluminum ions to form chemical bonds simultaneously with the amide nitrogen and carbonyl oxygen atoms on the peptide backbone.
Control of the Conductance of Engineered Protein Nanopores through Concerted Loop Motions
Authors: Zhuang Tiandi , Tamm Lukas K.
Published: April 2014

Protein nanopores have attracted much interest for nucleic acid sequencing, chemical sensing, and protein folding at the single molecule level. The outer membrane protein OmpG from E. coli stands out because it forms a nanopore from a single polypeptide chain. This property allows the separate engineering of each of the seven extracellular loops that control access to the pore. The longest of these loops, loop 6, has been recognized as the main gating loop that closes the pore at low pH values and opens it at high pH values. A method was devised to pin each of the loops to the embedding membrane and measure the single‐pore conductances of the resulting constructs. The electrophysiological and complementary NMR measurements show that the pinning of individual loops alters the structure and dynamics of neighboring and distant loops in a correlated fashion. Pinning loop 6 generates a constitutively open pore and patterns of concerted loop motions control access to the OmpG nanopore.
Säurekatalysierte oxidative Radikaladdition von Ketonen an Olefine
Authors: Schweitzer‐Chaput Bertrand , Demaerel Joachim , Engler Hauke , Klussmann Martin
Published: April 2014

Auf Basis einer mechanistischen Untersuchung haben wir eine Brønsted‐Säure‐katalysierte Bildung von Ketonradikalen entdeckt, die vermutlich über thermolabile Alkenylperoxide verläuft, welche in situ aus Ketonen und Hydroperoxiden gebildet werden. Diese Entdeckung wurde für eine Mehrkomponentenradikaladdition von nichtaktivierten Ketonen und tert‐Butylhydroperoxid an Olefine genutzt. Die erhaltenen γ‐Peroxyketone sind synthetisch nützliche Intermediate, welche zu 1,4‐Diketonen, Homoaldolprodukten oder Alkylketonen weiter umgesetzt werden können; in einem Eintopfverfahren gelang auch die Bildung eines pharmakologisch aktiven Pyrrols.
Control of the Electronic Ground State on an Electron‐Transfer Copper Site by Second‐Sphere Perturbations
Authors: Morgada Marcos N. , Abriata Luciano A. , Zitare Ulises , Alvarez‐Paggi Damian , Murgida Daniel H. , Vila Alejandro J.
Published: April 2014

The CuA center is a dinuclear copper site that serves as an optimized hub for long‐range electron transfer in heme–copper terminal oxidases. Its electronic structure can be described in terms of a σu* ground‐state wavefunction with an alternative, less populated ground state of πu symmetry, which is thermally accessible. It is now shown that second‐sphere mutations in the CuA containing subunit of Thermus thermophilus ba3 oxidase perturb the electronic structure, which leads to a substantial increase in the population of the πu state, as shown by different spectroscopic methods. This perturbation does not affect the redox potential of the metal site, and despite an increase in the reorganization energy, it is not detrimental to the electron‐transfer kinetics. The mutations were achieved by replacing the loops that are involved in protein–protein interactions with cytochrome c, suggesting that transient protein binding could also elicit ground‐state switching in the oxidase, which enables alternative electron‐transfer pathways.
Enantioselective Total Synthesis of (−)‐Lansai B and (+)‐Nocardioazines A and B
Authors: Wang Haoxuan , Reisman Sarah E.
Published: April 2014

The concise total syntheses of the bis(pyrroloindolines) (−)‐lansai B and (+)‐ nocardioazines A and B are reported. The key pyrroloindoline building blocks are rapidly prepared by enantioselective formal [3+2] cycloaddition reactions. The macrocycle of (+)‐nocardioazine A is constructed by an unusual intramolecular diketopiperazine formation.
Dithiolodithiole as a Building Block for Conjugated Materials
Authors: Schipper Derek J. , Moh Lionel C. H. , Müller Peter , Swager Timothy M.
Published: April 2014

The development of new conjugated organic materials for dyes, sensors, imaging, and flexible light emitting diodes, field‐effect transistors, and photovoltaics has largely relied upon assembling π‐conjugated molecules and polymers from a limited number of building blocks. The use of the dithiolodithiole heterocycle as a conjugated building block for organic materials is described. The resulting materials exhibit complimentary properties to widely used thiophene analogues, such as stronger donor characteristics, high crystallinity, and a decreased HOMO–LUMO gap. The dithiolodithiole (C4S4) motif is readily synthetically accessible using catalytic processes, and both the molecular and bulk properties of materials based on this building block can be tuned by judicious choice of substituents.
Narrative Therapy and Cultural Democracy: A Testimony View
Authors: Akinyela Makungu M.
Published: April 2014

In this article I discuss my personal introduction to narrative therapy as an African American family therapist and my discovery of the similarities between narrative practices and my own approaches to therapeutic work. I also examine the cultural relationship between narrative therapy and the therapies of a growing number of communities outside of European dominant culture. The article questions the dominant approach to multiculturalism in the field today and introduces the idea of cultural democracy as an alternative approach to managing the relationship between narrative and other Euro‐culture grounded therapies and the therapies of non‐European peoples which may be similar to, yet culturally unique from, Euro‐cultural therapies. This difference is not superficial or inconsequential. The article argues that a cultural democracy view challenges the emotional/psychologically colonizing links based in presumption of Euro‐cultural superiority of the ideas of Europe over the rest of the therapeutic world. This cultural democracy perspective creates a relationship of mutual respect and cross cultural influence between narrative therapy and other Euro‐cultural therapies and the therapies developed by non‐European peoples.
Narrative and Open Dialogue: Strangers in the Night or Easy Bedfellows?
Authors: Jackson Val , Fox Hugh
Published: April 2014

This paper briefly describes narrative and open dialogue approaches before exploring their shared values, ways of working, their differences and the possibilities for integration. Both authors have extensive experience in using a narrative therapy approach, while Val Jackson, a family and systemic psychotherapist, also uses an open dialogue approach in her work in an early intervention in psychosis service in Yorkshire, UK.
Uh Oh! I have Received an Unexpected Visitor: The Visitor's Name is Chronic Disease. A Brazilian family Therapy Approach
Authors: Abdalla Lúcia Helena , Novis Ana Luiza
Published: April 2014

Based on our clinical experience with people with chronic diseases, we have developed a narrative methodology we have named ‘The Pantry of Life’ (also known as ‘The Unexpected Visitor’). This reflective approach invites the person and their family to imagine and describe the appearance of adversity in their lives as an ‘Unexpected Visitor’ who arrives unexpectedly and uninvited. Consisting of six reflexive exercises, this methodology enables families who have felt hostage to the problem, to reclaim the authorship of the stories of their lives. By promoting new understandings, expanding conversations and validating the skills and resources of family members, those living with chronic diseases are offered a chance to respond to serious problems in playful and creative ways.
Ethnography, Co‐research and Insider Knowledges
Authors: Epston David
Published: April 2014

This piece revisits some of the intellectual histories of narrative practice, in particular the development of an ethnographic, co‐research approach to working with families. By tracing the influence of anthropological and sociological thought on the development of what has become ‘narrative therapy’, this piece invites current practitioners to read beyond the boundaries of any professional field in order to generate new forms of practice.
Michael White and Adventures Downunder
Authors: Denborough David
Published: April 2014

This paper explores the personal‐professional historical development of the work of the late Michael White. It was written at the request of Maurizio Andolfi and first published in Italian in Terapia Familiare No. 102, July 2013. It is published here for the first time in English with permission. The paper is written as a response to four questions: What were some of the key steps in Michael White's historical development from a personal‐professional perspective? From where did Michael draw his main inspirations? What have been his major contributions? And what has Michael left to the younger generations?
Bis(β‐diketiminato) lanthanide amides: synthesis, structure and catalysis for the polymerization of l‐lactide and ε‐caprolactone
Authors: Zheng Yu , Jiao Rui , Shen Xiao‐dong , Xue Ming‐qiang , Yao Ying‐ming , Zhang Yong , Shen Qi
Published: April 2014

Treatment of the chlorides (L2,6‐iPr2Ph)2LnCl (L2,6‐iPr2Ph = [(2,6‐iPr2C6H3)NC(Me)CHC(Me)N(C6H5)]−) with 1 equiv. of NaNH(2,6‐iPr2C6H3) afforded the monoamides (L2,6‐iPr2Ph)2LnNH(2,6‐iPr2C6H3) (Ln = Y (1), Yb (2)) in good yields. Anhydrous LnCl3 reacted with 2 equiv. of NaL2,6‐iPr2Ph in THF, followed by treatment with 1 equiv. of NaNH(2,6‐iPr2C6H3), giving the analogues (L2,6‐iPr2Ph)2LnNH(2,6‐iPr2C6H3) (Ln = Sm (3), Nd (4)). Two monoamido complexes stabilized by two L2‐Me ligands, (L2‐Me)2LnNH(2,6‐iPr2C6H3) (L2‐Me = [N(2‐MeC6H4)C(Me)]2CH)−; Ln = Y (5), Yb (6)), were also synthesized by the latter route. Complexes 1, 2, 3, 4, 5, 6 were fully characterized, including X‐ray crystal structure analyses. Complexes 1, 2, 3, 4, 5, 6 are isostructural. The central metal in each complex is ligated by two β‐diketiminato ligands and one amido group in a distorted trigonal bipyramid. All the complexes were found to be highly active in the ring‐opening polymerization of L‐lactide (L‐LA) and ε‐caprolactone (ε‐CL) to give polymers with relatively narrow molar mass distributions. The activity depends on both the central metal and the ligand (Yb < Y < Sm ≈ Nd and L2‐Me < L2,6‐iPr2Ph). Remarkably, the binary 3/benzyl alcohol (BnOH) system exhibited a striking ‘immortal’ nature and proved able to quantitatively convert 5000 equiv. of L‐LA with up to 100 equiv. of BnOH per metal initiator. All the resulting PLAs showed monomodal, narrow distributions (Mw/Mn = 1.06 − 1.08), with molar mass (Mn) decreasing proportionally with an increasing amount of BnOH. The binary 4/BnOH system also exhibited an ‘immortal’ nature in the polymerization of ε‐CL in toluene. Copyright © 2014 John Wiley & Sons, Ltd.
Production of biodegradable polyesters via enzymatic polymerization and solid state finishing
Authors: Kanelli Maria , Douka Aliki , Vouyiouka Stamatina , Papaspyrides Constantine D. , Topakas Evangelos , Papaspyridi Lefki‐Maria , Christakopoulos Paul
Published: April 2014

The synthesis of aliphatic polyesters (PEs) derived from diols (1,4‐butanediol and 1,8‐octanediol) and diacids or their derivatives (diethyl succinate, sebacic acid, 1,12‐dodecanedioic acid, and 1,14‐tetradecanedioic acid) was achieved in order to produce poly(butylene succinate) (PE 4.4), poly(octylene sebacate) (PE 8.10), poly(octylene dodecanate) (PE 8.12), and poly(octylene tetradecanate) (PE 8.14). The herein suggested procedure involved two stages, both sustainable and in accordance with the principles of “green” polymerization. The first comprised an enzymatic prepolymerization under vacuum, in the presence of diphenylether as solvent using Candida antarctica lipase B as biocatalyst, whereas a low‐temperature postpolymerization step [solid state polymerization (SSP)] followed in order to upgrade the PEs quality. In the enzymatically synthesized prepolymers, the range of number–average molecular weight attained was from 3700 to 8000 g/mol with yields reaching even 97%. Subsequently, SSP of PE 4.4 and 8.12 took place under vacuum or flowing nitrogen and lasted 10–48 h, at temperatures close to the prepolymer melting point (Tm − TSSP varied between 4°C and 14°C). The solid state finishing led to increase in the molecular weight depending on the prepolymer type, and it also contributed to improvement of the physical characteristics and the thermal properties of the enzymatically synthesized PEs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40820.
Thermal–oxidative degradation and accelerated aging behavior of polyamide 6/epoxy resin‐modified montmorillonite nanocomposites
Authors: Xia Lei , Xiong Jinsu , Shentu Baoqing , Weng Zhixue
Published: April 2014

Polyamide 6 (PA6) nanocomposites based on epoxy resin‐modified montmorillonite (EP‐MMT) were prepared by melt processing using a typical twin‐screw extruder. X‐ray diffraction combined with transmission electron microscopy was applied to elucidate the structure and morphology of PA6/EP‐MMT nanocomposites, suggesting a nearly exfoliated structure in the nanocomposite with 2 wt % EP‐MMT (PA6/2EP‐MMT) and a partial exfoliated‐partial intercalated structure in PA6/4 wt %EP‐MMT nanocomposite (PA6/4EP‐MMT). The thermogravimetric analysis under air atmosphere was conducted to characterize the thermal–oxidative degradation behavior of the material, and the result indicated that the presence of EP‐MMT could inhibit the thermal‐oxidative degradation of PA6 effectively. Accelerated heat aging in an air circulating oven at 150°C was applied to assess the thermal–oxidative stability of PA6 nanocomposites through investigation of reduced viscosity, tensile properties, and chemical structure at various time intervals. The results indicated that the incorporation of EP‐MMT effectively enhanced the thermal–oxidative stability of PA6, resulting in the high retention of reduced viscosity and tensile strength, and the low ratio of terminal carboxyl group to amino group. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40825.
Fabrication of PAN/PHCS adsorptive UF membranes with enhanced performance for dichlorophenol removal from water
Authors: Gao Yan , Qiao Yuan , Yang Sen
Published: April 2014

A series of novel polyacrylonitrile (PAN) adsorptive UF membranes were prepared via the nonsolvent induced phase inversion method using adsorbent‐amphiphilic porous hollow carbonaceous microspheres (PHCSs) as additive. The resulted PAN/PHCS membranes were demonstrated to have better mechanical strength than the pure PAN membrane. The water fluxes of the PAN/PHCS membranes were slightly decrease; however, the rejections to pepsin were maintained at a high level (81–86%). The properties of the PAN/PHCS membranes for 2,4‐dichlorophenol removal from water were investigated. The results showed that 2,4‐dichlorophenol could be rapidly removed from water via adsorption mechanism by PAN/PHCS membranes, and the maximum reduction efficiency was up to 70%. The adsorption of 2,4‐dichlorophenol to the membranes was reversible and the membranes could be regenerated facilely by water washing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40837.
Genetic diversity of two Philippine native freshwater goby species (Perciformes: Gobiidae): implications for conservation
Authors: Ardestani Goli , Rogelio Diana Rose O. , Reyes Roberto C. , Laude Rita P.
Published: April 2014

Appropriate decision‐making in conservation programmes requires an understanding of the population genetic structure of various indigenous species. However, in lake and river ecosystems rated as biodiversity conservation priority areas in the Philippines, the diversity of many species remains uncharacterized.

To address the existing gap, genetic diversity of two native freshwater fishes, Glossogobius celebius (Valenciennes, 1837) and Glossogobius giuris (Hamilton, 1822) was measured. Genetic structure and estimates of genetic variation for each species was determined using isozyme analysis.

A higher level of genetic variation was observed within G. celebius populations compared with G. giuris. Genetic structure indicated that the observed genetic variation in G. giuris is due to the variation among the populations. The results suggest the presence of geographical barriers even in adjacent aquatic ecosystems that could restrict gene flow among G. giuris populations.

This study supports the need for immediate conservation interventions for both species as they show a low level of genetic diversity in addition to being threatened in their own environment. Possible measures include translocation and establishment of a refuge population of the species studied to be complemented with location‐specific strategies that would enhance their habitat conditions. In addition, education and enhancing the awareness of the local community regarding habitat protection are strongly recommended.

Copyright © 2014 John Wiley & Sons, Ltd.
In‐text author citation analysis: Feasibility, benefits, and limitations
Authors: Zhao Dangzhi , Strotmann Andreas
Published: April 2014

This article explores the feasibility, benefits, and limitations of in‐text author citation analysis and tests how well it works compared with traditional author citation analysis using citation databases. In‐text author citation analysis refers to author‐based citation analysis using in‐text citation data from full‐text articles rather than reference data from citation databases. It has the potential to help with the application of citation analysis to research fields such as the social sciences that are not covered well by citation databases and to support weighted citation and cocitation counting for improved citation analysis results. We found that in‐text author citation analysis can work as well as traditional citation analysis using citation databases for both author ranking and mapping if author name disambiguation is performed properly. Using in‐text citation data without any author name disambiguation, ranking authors by citations is useless, whereas cocitation analysis works well for identifying major specialties and their interrelationships with cautions required for the interpretation of small research areas and some authors' memberships in specialties.
Bridging the virtual and real: The relationship between web content, linkage, and geographical proximity of social movements
Authors: Benjamin Victor , Chen Hsinchun , Zimbra David
Published: April 2014

As the Internet becomes ubiquitous, it has advanced to more closely represent aspects of the real world. Due to this trend, researchers in various disciplines have become interested in studying relationships between real‐world phenomena and their virtual representations. One such area of emerging research seeks to study relationships between real‐world and virtual activism of social movement organization (SMOs). In particular, SMOs holding extreme social perspectives are often studied due to their tendency to have robust virtual presences to circumvent real‐world social barriers preventing information dissemination. However, many previous studies have been limited in scope because they utilize manual data‐collection and analysis methods. They also often have failed to consider the real‐world aspects of groups that partake in virtual activism. We utilize automated data‐collection and analysis methods to identify significant relationships between aspects of SMO virtual communities and their respective real‐world locations and ideological perspectives. Our results also demonstrate that the interconnectedness of SMO virtual communities is affected specifically by aspects of the real world. These observations provide insight into the behaviors of SMOs within virtual environments, suggesting that the virtual communities of SMOs are strongly affected by aspects of the real world.
Homogeneous Oxidation of Water by Iron Complexes with Macrocyclic Ligands
Authors: Zhang Biaobiao , Li Fei , Yu Fengshou , Cui Honghua , Zhou Xu , Li Hua , Wang Yong , Sun Licheng
Published: April 2014

The activity of eleven separated iron complexes and nine in situ‐generated iron complexes towards catalytic water oxidation have been examined in aqueous solutions with Ce(NH4)2(NO3)6 as the oxidant. Two iron complexes bearing tridentate and tetradentate macrocyclic ligands were found to be novel water oxidation catalysts. The one with tetradentate ligand exhibited a promising activity with a turnover number of 65 for oxygen evolution.
Physician‐Commanded Six‐DOF Robotic Manipulation for Target Localization in Conformal Radiotherapy
Authors: Chang Wen‐Chung , Chen Chin‐Sheng , Liu Chia‐Yuan , Chen Yu‐Jen
Published: April 2014

To effectively improve treatment precision in conformal radiotherapy, ultrasound sensing is employed to detect tumors in real time. In order to implement this new configuration, the physician operating the ultrasound probe must not stay in the radiotherapy room. This motivates the development of a physician‐commanded robotic manipulation system for target localization in conformal radiotherapy. The proposed robotic control system is in eye‐to‐hand configuration with binocular vision and force sensing. The ultrasound probe mounted on the end‐effector of the manipulator is controlled to follow the pose commanded by the physician. Based on the measurements from a six‐axis force sensor, the probe can be controlled further to maintain the desired contact force against the possibly‐deforming treatment surface. The proposed hybrid force and vision‐based control approach has been validated by experimenting with a six‐degrees‐of‐freedom industrial manipulator to allow clear ultrasound images.
iOD907, the first genome‐scale metabolic model for the milk yeast Kluyveromyces lactis
Authors: Dias Oscar , Pereira Rui , Gombert Andreas K. , Ferreira Eugénio C. , Rocha Isabel
Published: April 2014

We describe here the first genome‐scale metabolic model of Kluyveromyces lactis, iOD907. It is partially compartmentalized (four compartments), composed of 1867 reactions and 1476 metabolites. The iOD907 model performed well when comparing the positive growth of K. lactis to Biolog experiments and to an online catalogue of strains that provides information on carbon sources in which K. lactis is able to grow. Chemostat experiments were used to adjust non‐growth‐associated energy requirements, and the model proved accurate when predicting the biomass, oxygen and carbon dioxide yields. When compared to published experiments, in silico knockouts accurately predicted in vivo phenotypes. The iOD907 genome‐scale metabolic model complies with the MIRIAM (minimum information required for the annotation of biochemical models) standards for the annotation of enzymes, transporters, metabolites and reactions. Moreover, it contains direct links to Kyoto encyclopedia of genes and genomes (KEGG; for enzymes, metabolites and reactions) and to the Transporters Classification Database (TCDB) for transporters, allowing easy comparisons to other models. Furthermore, this model is provided in the well‐established systems biology markup language (SBML) format, which means that it can be used in most metabolic engineering platforms, such as OptFlux or Cobra. The model is able to predict the behavior of K. lactis under different environmental conditions and genetic perturbations. Furthermore, by performing simulations and optimizations, it can be important in the design of minimal media and will allow insights on the milk yeast's metabolism, as well as identifying metabolic engineering targets for improving the production of products of interest.
Comparison of energy metabolism in liver grafts from donors after circulatory death and donors after brain death during cold storage and reperfusion
Authors: Perera M T P R , Richards D A , Silva M A , Ahmed N , Neil D A , Murphy N , Mirza D F
Published: April 2014

Background

Donation after circulatory death (DCD) liver grafts have supplemented the donor organ pool, but certain adverse outcomes have prevented exploration of the full potential of such organs. The aim of this study was to determine key differences in basic energy metabolism between DCD and donation after brainstem death (DBD) grafts.

Methods

Microdialysis samples from DCD and DBD allograft parenchyma from cold storage to 48 h after reperfusion were analysed by colorimetric methods. Interstitial lactate, pyruvate and glycerol levels were measured and the lactate/pyruvate ratio was calculated to estimate energy depletion of the grafts. Histological features of ischaemia and reperfusion injury were assessed.

Results

Donor age, extent of steatosis and cold ischaemia time were comparable between ten DCD and 20 DBD organs. DCD grafts had higher levels of interstitial lactate (median 11·6 versus 1·2 mmol/l; P = 0·015) and increased lactate/pyruvate ratio (792 versus 38; P = 0·001) during cold storage. There was no significant difference in glycerol levels between DCD and DBD grafts (225·1 versus 127·5 µmol/l respectively; P = 0·700). Rapid restoration of energy levels with lactate clearance, increased pyruvate levels and reduced lactate/pyruvate ratio was seen following reperfusion of functioning DCD grafts, parallel with levels in DBD grafts. Histology revealed more pronounced glycogen depletion in DCD grafts. Three allografts that failed owing to primary non-function showed energy exhaustion with severe glycogen depletion.

Conclusion

Liver grafts from DCD donors exhibited depletion of intracellular energy reserves during cold storage. Failed allografts showed severe energy depletion. Modified organ preservation techniques to minimize organ injury related to altered energy metabolism may enable better utilization of donor organs after circulatory death.
Modulation of mAb quality attributes using microliter scale fed‐batch cultures
Authors: Rouiller Yolande , Périlleux Arnaud , Vesin Marie‐Noëlle , Stettler Matthieu , Jordan Martin , Broly Hervé
Published: April 2014

A high‐throughput DoE approach performed in a 96‐deepwell plate system was used to explore the impact of media and feed components on main quality attributes of a monoclonal antibody. Six CHO‐S derived clonal cell lines expressing the same monoclonal antibody were tested in two different cell culture media with six components added at three different levels. The resulting 384 culture conditions including controls were simultaneously tested in fed‐batch conditions, and process performance such as viable cell density, viability, and product titer were monitored. At the end of the culture, supernatants from each condition were purified and the product was analyzed for N‐glycan profiles, charge variant distribution, aggregates, and low molecular weight forms. The screening described here provided highly valuable insights into the factors and combination of factors that can be used to modulate the quality attributes of a molecule. The approach also revealed specific intrinsic differences of the selected clonal cell lines ‐ some cell lines were very responsive in terms of changes in performance or quality attributes, whereas others were less affected by the factors tested in this study. Moreover, it indicated to what extent the attributes can be impacted within the selected experimental design space. The outcome correlated well with confirmations performed in larger cell culture volumes such as small‐scale bioreactors. Being fast and resource effective, this integrated high‐throughput approach can provide information which is particularly useful during early stage cell culture development. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:571–583, 2014
Efficient and effective cage generation by region decomposition
Authors: Xian Chuhua , Li Guiqing , Xiong Yunhui
Published: April 2014

Cage‐based deformation has become a popular method for shape deformation in computer graphics and animation. To edit a shape first requires a cage to be built to envelop the target model which is a tedious work by manual approaches. In this paper, we develop an automatic method to generate the cage for a model using voxelization based decomposition. We first voxelize the input model, and then use the seed filling algorithm to group the inner voxels. By dilating the inner voxel groups, we decompose the model into broad regions and narrow regions. Then we construct partial cages using different strategies and unite them to get a cage. Experiment results demonstrate that our method is effective, efficient as well as robust to model transformation. Copyright © 2014 John Wiley & Sons, Ltd.