bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling the cost-effectiveness of carotid endarterectomy for asymptomatic stenosis
Authors: Thapar A , Garcia Mochon L , Epstein D , Shalhoub J , Davies A H 
Published: November 2012

Abstract

Background
The aim of this study was to model the cost-effectiveness of carotid endarterectomy for asymptomatic stenosis versus medical therapy based on 10-year data from the Asymptomatic Carotid Surgery Trial (ACST).

Methods
This was a cost–utility analysis based on clinical effectiveness data from the ACST with UK-specific costs and stroke outcomes. A Markov model was used to calculate the incremental cost-effectiveness ratio (ICER, or cost per additional quality-of-life year) for a strategy of early endarterectomy versus medical therapy for the average patient and published subgroups. An exploratory analysis considered contemporary event rates.

Results
The ICER was £ 7584 per additional quality-adjusted life-year (QALY) for the average patient in the ACST. At thresholds of £ 20 000 and £ 30 000 there was a 74 and 84 per cent chance respectively of early endarterectomy being cost-effective. The ICER for men below 75 years of age was £ 3254, and that for men aged 75 years or above was £ 71 699. For women aged under 75 years endarterectomy was less costly and more effective than medical therapy; for women aged 75 years or more endarterectomy was less effective and more costly than medical therapy. At contemporary perioperative event rates of 2·7 per cent and background any-territory stroke rates of 1·6 per cent, early endarterectomy remained cost-effective.

Conclusion
In the ACST, early endarterectomy was predicted to be cost-effective in those below 75 years of age, using a threshold of £ 20 000 per QALY. If background any-territory stroke rates fell below 1 per cent per annum, early endarterectomy would cease to be cost-effective.
Lymphadenectomy around the left renal vein in Siewert type II adenocarcinoma of the oesophagogastric junction
Authors: Mine S , Sano T , Hiki N , Yamada K , Nunobe S , Yamaguchi T 
Published: November 2012

Abstract

Background
The extent of lymphadenectomy in patients with Siewert type II adenocarcinoma of the oesophagogastric junction is controversial. The aim of this study was to investigate lymph node involvement around the left renal vein.

Methods
Lymph node involvement and prognosis in patients with Siewert type II cancers treated by R0–1 surgical resection were investigated, with regard to lymphadenectomy around the left renal vein. Based on the incidence of involvement at each node, the node stations were divided into three tiers (first tier, more than 20 per cent involvement; second tier, 10–20 per cent involvement; third tier, less than 10 per cent involvement).

Results
Of 150 patients with type II oesophagogastric adenocarcinoma, 94 had left renal vein lymphadenectomy. The first lymph node tier included nodes along the lesser curvature, right cardia, left cardia and left gastric artery, with involvement of 28·0–46·0 per cent and a 5-year survival rate of 42–53 per cent in patients with positive nodes. The nodes around the lower mediastinum, left renal vein, splenic artery and coeliac axis constituted the second tier, with involvement of 12·7–18 per cent and a 5-year survival rate of 11–35 per cent. With regard to the left renal vein, the incidence of involvement was 17 per cent and the 5-year rate survival rate was 19 per cent. Multivariable analysis showed that left renal vein lymphadenectomy was an independent prognostic factor in patients with pathological tumour category pathological T3–4 disease (hazard ratio 0·51, 95 per cent confidence interval 0·26 to 0·99; P = 0·048).

Conclusion
Left renal vein nodal involvement is similar to that seen along the splenic artery, in the lower mediastinum and coeliac axis, with similar impact on patient survival.
S‐Adenosyl‐Methionine‐Dependent Methyltransferases: Highly Versatile Enzymes in Biocatalysis, Biosynthesis and Other Biotechnological Applications
Authors: Struck Anna‐Winona , Thompson Mark L. , Wong Lu Shin , Micklefield Jason 
Published: November 2012

AbstractS‐adenosyl methionine (SAM) is a universal biological cofactor that is found in all branches of life where it plays a critical role in the transfer of methyl groups to various biomolecules, including DNA, proteins and small‐molecule secondary metabolites. The methylation process thus has important implications in various disease processes and applications in industrial chemical processing. This methyl transfer is catalysed by SAM‐dependent methyltransferases (MTases), which are by far the largest groups of SAM‐dependent enzymes. A significant amount is now known regarding the structural biology and enzymology of these enzymes, and, consequently, there is now significant scope for the development of new MTases and SAM analogues for applications from biomolecular imaging to biocatalytic industrial processes. This review will focus on current efforts in the manipulation of class I and V SAM‐dependent MTases and the use of synthetic SAM analogues, which together offer the best prospects for rational redesign towards biotechnological applications. Firstly, metabolic engineering of organisms incorporating small‐molecule MTases is discussed; this can be applied in a variety of areas from the industrial bioprocessing of flavourants and antibiotics to frontier research in biofuel production and bioremediation. Secondly, the application of MTases in combination with SAM analogues is reviewed; this allows the tagging of proteins and oligonucleotides with moieties other than the methyl group. Such tagging allows the isolation of the tagged biomolecule and aids its visualisation by a range of analytical methods. The review then summarises the potential advantages of MTase‐mediated chemistry and offers some future perspectives on downstream applications.
Host–Guest Interactions of Phosphorescent Molecular Tweezers Based on an Alkynylplatinum(II) Terpyridine System with Polyaromatic Hydrocarbons
Authors: Tanaka Yuya , Wong Keith Man‐Chung , Yam Vivian Wing‐Wah 
Published: November 2012

AbstractHost–guest interactions of a molecular tweezer complex 1 with various planar organic molecules including polyaromatic hydrocarbons (PAHs) were investigated by 1D and 2D 1H NMR spectroscopy, UV/Vis absorption and emission titration studies. 2D and DOSY NMR spectroscopies support the sandwiched binding mode based on 1:1 host–guest interactions. The binding constants (KS) of complex 1 for various PAHs were determined by NMR titration studies and the values were found to span up to an order of 104 M−1 for coronene to no observable interaction for benzene, indicating that the π‐surface area is important for such host–guest interactions. The substituent effect on the host–guest interaction based on the guest series of 9‐substituted anthracenes was also studied. In general, a stronger interaction was observed for the anthracene guest with electron‐donating groups, although steric and π‐conjugation factors cannot be completely excluded. The photophysical responses of complex 1 upon addition of various PAHs were measured by UV/Vis and emission titration studies. The UV/Vis absorption spectra were found to show a drop in absorbance of the metal‐to‐ligand charge‐transfer (MLCT) and ligand‐to‐ligand charge‐transfer (LLCT) admixture band upon addition of various guest molecules to 1, whereas the emission behavior was found to change differently depending on the guest molecules, showing emission enhancement and/or quenching. It was found that emission quenching occurred either via energy transfer or electron transfer pathway or both, while emission enhancement was caused by the increase in rigidity of complex 1 as a result of host–guest interaction.
Low Catalyst Loading in Ring‐Closing Metathesis Reactions
Authors: Kadyrov Renat 
Published: November 2012

AbstractAn efficient procedure is described for ring‐closing metathesis reactions. A conversion of 95 % for diethyl diallylmalonate in dilute solution could be achieved within a few minutes, reaching TOF=4173 min−1, with very low loading of commercially available Ru catalysts that contained unsaturated NHC ligands. In general, only 50 to 250 ppm of the catalyst is required to achieve near‐quantitative conversion into a broad variety of 5–16‐membered heterocyclic compounds. The practicality of this procedure was illustrated in the synthesis of 5–8‐membered N‐tert‐butoxycarbonyl (N‐Boc)‐ and N‐para‐toluenesulfonyl (N‐Ts)‐protected cyclic amines and 9–16‐membered lactones. The synthesis of macrocyclic proline‐based lactams required slightly higher catalyst loadings. Along with monocyclic products, oligomeric byproducts, mostly cyclodimers, were isolated and characterized.
On the Solution Behaviour of Benzyllithium⋅(−)‐Sparteine Adducts and Related Lithium Organyls – A Case Study on Applying 7Li,15N{1H} HMQC and Further NMR Methods, Including Some Investigation into Asymmetric Synthesis
Authors: Casimiro María , Oña‐Burgos Pascual , Meyer Jens , Styra Steffen , Kuzu Istemi , Breher Frank , Fernández Ignacio 
Published: November 2012

Abstract2D 7Li,15N heteronuclear shift correlation through scalar coupling has successfully been applied to several lithium organyls consisting of polydentate N ligands such as N,N,N′,N′‐tetramethylethylenediamine (tmeda), N,N,N′,N′,N′′‐pentamethyldiethylentriamine (pmdta) and (−)‐sparteine. Structural insights on the conformation of benzyllithium⋅pmdta (5) in a toluene solution and the strength of ion pairing in combination with PGSE NMR measurements, 1H,1H‐NOESY and 1H,7Li‐HOESY experiments are presented. By studying in detail the formation of 5 in solution, a transient species has been observed for the first time and assigned to a pre‐complex of nBuLi and pmdta. In addition, the solution behaviour of the complex formed between benzyllithium and (−)‐sparteine (8) has been studied by PGSE and multinuclear NMR spectroscopy. The straightforward synthesis and first applications in asymmetric lithiations are also reported, which show that the new system benzyllithium⋅(−)‐sparteine (8) provide poorer enantioselective induction than the classical nBuLi⋅(−)‐sparteine (6). The results were supported by deprotonation experiments confirming that the formation of 8 relies on two relevant factors, namely temperature and lithiating reagent. The existence of 8 may thus interfere with the asymmetric induction when the system nBuLi⋅ (−)‐sparteine is used in the enantioselective deprotonations of N‐Boc‐N‐(p‐methoxyphenyl)‐benzylamine conducted in toluene.
Synthesis, Structure, and Theoretical Study of Trifluoromethyl Derivatives of C84(22) Fullerene
Authors: Chang Kaichin , Fritz Maria A. , Tamm Nadezhda B. , Goryunkov Alexey A. , Sidorov Lev N. , Chen Chuanbao , Yang Shangfeng , Kemnitz Erhard , Troyanov Sergey I. 
Published: November 2012

AbstractTrifluoromethylation of higher fullerene mixtures with CF3I was performed in ampoules at 400 to 420 and 550 to 560 °C. HPLC separation followed by crystal growth and X‐ray diffraction studies allowed the structure elucidation of nine CF3 derivatives of D2‐C84 (isomer 22). Molecular structures of two isomers of C84(22)(CF3)12, two isomers of C84(22)(CF3)14, four isomers of C84(22)(CF3)16, and one isomer of C84(22)(CF3)20 were discussed in terms of their addition patterns and relative formation energies. DFT calculations were also used to predict the most stable molecular structures of lower CF3 derivatives, C84(22)(CF3)2–10. It was found that the addition of CF3 groups to C84(22) is governed by two rules: additions can only occur at para positions of C6(CF3)2 hexagons and no additions can occur at triple‐hexagon‐junction positions on the fullerene cage.
Prompt and Slow Electron‐Detachment‐Dissociation/Electron‐Photodetachment‐Dissociation of a 21‐Mer Peptide
Authors: Pérot‐Taillandier Marie , Zirah Séverine , Enjalbert Quentin , Antoine Rodolphe , Lemoine Jérôme , Dugourd Philippe , Rebuffat Sylvie , Tabet Jean‐Claude , Afonso Carlos 
Published: November 2012

AbstractElectron detachment dissociation (EDD) and electron photodetachment dissociation (EPD) are relatively new dissociation methods that involve electron detachment followed by radical‐driven dissociation from multiply deprotonated species. EDD yields prompt dissociation whereas only electron detachment is obtained by EPD; subsequent vibrational activation of the charge‐reduced radical anion is required to obtain the product ions. Herein, the fragmentation patterns that were obtained by EDD and by vibrational activation of the charge‐reduced radical anions that were produced through EDD or EPD (activated‐EDD and activated‐EPD) were compared. The observed differences were related to the dissociation kinetics and/or the contribution of electron‐induced dissociation (EID). Time‐resolved double‐resonance experiments were performed to measure the dissociation rate constants of the EDD product ions. Differences in the formation kinetics were revealed between the classical EDD/EPD ′a.i/′′xj complementary ions and some ′a.i/ci/′′′z.j product ions, which were produced with slower dissociation rate constants, owing to the presence of specific neighbouring side chains. A new fragmentation pathway is proposed for the formation of the slow‐kinetics ′a.i ions.
Coordinative Interactions between Porphyrins and C60, La@C82, and La2@C80
Authors: Tsuchiya Takahiro , Rudolf Marc , Wolfrum Silke , Radhakrishnan Shankara Gayathri , Aoyama Ryo , Yokosawa Yuya , Oshima Azusa , Akasaka Takeshi , Nagase Shigeru , Guldi Dirk M. 
Published: November 2012

AbstractFor the first time, a C60 derivative (1) and two different lanthanum metallofullerene derivatives, La@C82Py (2) and La2@C80Py (3), that feature a pyridyl group as a coordination site for transition‐metal ions have been synthesized and integrated as electron acceptors into coordinative electron‐donor/electron‐acceptor hybrids. Zinc tetraphenylporphyrin (ZnP) served as an excited‐state electron donor in this respect. Our investigations, by means of steady‐state and time‐resolved photophysical techniques found that electron transfer governs the excited‐state deactivation in all of these systems, namely 1/ZnP, 2/ZnP, and 3/ZnP, whereas, in the ground state, notable electronic interactions are lacking. Variation of the electron‐accepting fullerene or metallofullerene moieties provides the incentive for fine‐tuning the binding constants, the charge‐separation kinetics, and the charge‐recombination kinetics. To this end, the binding constants, which ranged from log Kassoc=3.94–4.38, are dominated by axial coordination, with minor contributions from the orbital overlap of the curved and planar π systems. The charge‐separation and charge‐recombination kinetics, which are in the order of 1010 and 108 s−1, relate to the reduction potential of the fullerene and metallofullerenes, respectively.
A Bioinorganic View of Alzheimer’s Disease: When Misplaced Metal Ions (Re)direct the Electrons to the Wrong Target
Authors: Faller Peter , Hureau Christelle 
Published: November 2012

AbstractMetal ions Cu, Zn and Fe, seem to play a pivotal role in Alzheimer’s disease and other neurodegenerative diseases. In order to understand this in a broader sense, one has to considerer the peculiarities of metal metabolism in the brain compared to most other tissues, as well as the importance of the redox active metal ions, Fe and Cu, in oxygen metabolism and the connected oxidative stress.
Synthesis and Molecular Properties of Acceptor‐Substituted Squaraine Dyes
Authors: Mayerhöffer Ulrich , Gsänger Marcel , Stolte Matthias , Fimmel Benjamin , Würthner Frank 
Published: November 2012

AbstractA broad series of more than 20 acceptor‐substituted squaraines was synthesized that feature different acceptor functionalities at the central squaraine four‐membered ring. The influence of these acceptor units on the reactivity of semisquaraine precursors and stability of the respective squaraines were explored. Thereby the dicyanovinyl group was found to be the most versatile acceptor group that enabled various modifications at the donor moiety of the squaraine scaffold, leading to an extended series of dicyanovinyl‐functionalized squaraines. The variation of donor units afforded a set of NIR fluorophores that cover a wavelength region from the visible at about 650 nm far into the NIR up to 920 nm with fluorescence quantum yields between 0.93 and 0.11 and outstanding optical brightness. This excellent optical property is related to a rigid molecular scaffold that is fixed in an all‐cis configuration by the additional dicyanovinyl acceptor unit. The change of the molecular symmetry from C2h to C2v upon functionalization of the squaraine core with dicyanovinyl acceptor group has been confirmed in solution by electro‐optical absorption (EOA) spectroscopy, revealing permanent ground‐state dipole moments μg in the range between 4.3 and 6.4 D. These dipole moments direct an antiparallel packing of the molecules in the solid state according to single‐crystal X‐ray analyses achieved for four dicyanovinyl‐functionalized squaraines. The structural properties, the EOA results, as well as the band shapes of the optical spectra indicate that these polymethine dyes are cyanine‐type chromophores. It is worth noting that the orientation of the dipole moment vectors is orthogonal to the orientation of the transition dipole moment vectors, which is an uncommon but characteristic feature of this rather novel class of polymethine dyes. With regard to applications of these dyes in organic solar cells, their redox properties were also studied by cyclic voltammetry.
Efficient Synthesis of Substituted 3‐Azabicyclo[3.1.0]hexan‐2‐ones from 2‐Iodocyclopropanecarboxamides Using a Copper‐Free Sonogashira Coupling
Authors: de Carné‐Carnavalet Benoît , Archambeau Alexis , Meyer Christophe , Cossy Janine , Folléas Benoît , Brayer Jean‐Louis , Demoute Jean‐Pierre 
Published: November 2012

AbstractThe copper‐free Sonogashira coupling between N‐substituted cis‐ 2‐iodocyclopropanecarboxamides and terminal aryl‐, heteroaryl‐alkynes or enynes, followed by 5‐exo‐dig cyclization of the nitrogen amide onto the carbon–carbon triple bond, provides a remarkably efficient access to a variety of substituted 4‐methylene‐3‐azabicyclo[3.1.0]hexan‐2‐ones in excellent yields. Protonation of these latter enamides generates bicyclic N‐acyliminium ions that can be involved in Pictet–Spengler cyclizations leading to new 3‐azabicyclo[3.1.0]hexan‐2‐ones, possessing a quaternary stereocenter at C4, with high diastereoselectivities. This strategy constitutes an attractive complementary alternative to the classical route that relies on the addition of organometallic reagents to cyclopropyl imides.
Synthesis of (−)‐Morphine: Application of Sequential Claisen/Claisen Rearrangement of an Allylic Vicinal Diol
Authors: Ichiki Masato , Tanimoto Hiroki , Miwa Shohei , Saito Ryosuke , Sato Takaaki , Chida Noritaka 
Published: November 2012

AbstractA detailed exploration of the synthesis of (−)‐morphine based on sequential [3,3]‐sigmatropic rearrangements is described. The sequential Claisen/Claisen rearrangements of an allylic vicinal diol resulted in the stereoselective formation of the two contiguous carbon centers, including a sterically encumbered quaternary carbon, in a single operation. The two ethyl esters generated in this reaction were successfully differentiated during a subsequent Friedel–Crafts‐type cyclization. The (−)‐morphine double bond was introduced at a late stage in our first‐generation synthesis, but was formed at an earlier stage in the second‐generation synthesis, resulting in a more efficient route to the end product.
PtM (M=Cu, Co, Ni, Fe) Nanocrystals: From Small Nanoparticles to Wormlike Nanowires by Oriented Attachment
Authors: Yu Xiaofei , Wang Dingsheng , Peng Qing , Li Yadong 
Published: November 2012

AbstractPtM (M=Cu, Co, Ni, Fe) wormlike nanowires with excellent catalytic activities were produced by a hydrothermal method. Based on the experiment results, PtM nanoparticles grew into nanowires through oriented attachment. The electrocatalytic activities of these nanowires toward methanol oxidation were also studied by cyclic voltammetry and chronoamperometry measurements. The synthesized PtM nanowires showed higher catalytic activity and stability for methanol oxidation than Pt nanowires and commercial Pt black.
Convergent Modulation of Singlet and Triplet Excited States of Phosphine‐Oxide Hosts through the Management of Molecular Structure and Functional‐Group Linkages for Low‐Voltage‐Driven Electrophosphorescence
Authors: Han Chunmiao , Zhang Zhensong , Xu Hui , Xie Guohua , Li Jing , Zhao Yi , Deng Zhaopeng , Liu Shiyong , Yan Pengfei 
Published: November 2012

AbstractThe controllable tuning of the excited states in a series of phosphine‐oxide hosts (DPExPOCzn) was realized through introducing carbazolyl and diphenylphosphine‐oxide (DPPO) moieties to adjust the frontier molecular orbitals, molecular rigidity, and the location of the triplet excited states by suppressing the intramolecular interplay of the combined multi‐insulating and meso linkage. On increasing the number of substituents, simultaneous lowering of the first singlet energy levels (S1) and raising of the first triplet energy levels (T1, about 3.0 eV) were achieved. The former change was mainly due to the contribution of the carbazolyl group to the HOMOs and the extended conjugation. The latter change was due to an enhanced molecular rigidity and the shift of the T1 states from the diphenylether group to the carbazolyl moieties. This kind of convergent modulation of excited states not only facilitates the exothermic energy transfer to the dopants in phosphorescent organic light‐emitting diodes (PHOLEDs), but also realizes the fine‐tuning of electrical properties to achieve the balanced carrier injection and transportation in the emitting layers. As the result, the favorable performance of blue‐light‐emitting PHOLEDs was demonstrated, including much‐lower driving voltages of 2.6 V for onset and 3.0 V at 100 cd m−2, as well as a remarkably improved E.Q.E. of 12.6 %.
Small‐Molecule APOBEC3G DNA Cytosine Deaminase Inhibitors Based on a 4‐Amino‐1,2,4‐triazole‐3‐thiol Scaffold
Authors: Olson Margaret E. , Li Ming , Harris Reuben S. , Harki Daniel A. 
Published: November 2012

AbstractAPOBEC3G (A3G) is a single‐stranded DNA cytosine deaminase that functions in innate immunity against retroviruses and retrotransposons. Although A3G can potently restrict Vif‐deficient HIV‐1 replication by catalyzing excessive levels of G→A hypermutation, sublethal levels of A3G‐catalyzed mutation may contribute to the high level of HIV‐1 fitness and its incurable prognosis. To chemically modulate A3G catalytic activity with the goal of decreasing the HIV‐1 genomic mutation rate, we synthesized and biochemically evaluated a class of 4‐amino‐1,2,4‐triazole‐3‐thiol small‐molecule inhibitors identified by high‐throughput screening. This class of compounds exhibits low‐micromolar (3.9–8.2 μM) inhibitory potency and remarkable specificity for A3G versus the related cytosine deaminase, APOBEC3A. Chemical modification of inhibitors, A3G mutational screening, and thiol reactivity studies implicate C321, a residue proximal to the active site, as the critical A3G target for this class of molecules.
Consciousness and the structuring property of typical data
Authors: Mason Jonathan W. D. 
Published: November 2012

AbstractThe theoretical base for consciousness, in particular, an explanation of how consciousness is defined by the brain, has long been sought by science. We propose a partial theory of consciousness as relations defined by typical data. The theory is based on the idea that a brain state on its own is almost meaningless but in the context of the typical brain states, defined by the brain's structure, a particular brain state is highly structured by relations. The proposed theory can be applied and tested both theoretically and experimentally. Precisely how typical data determines relations is fully established using discrete mathematics. © 2012 Wiley Periodicals, Inc. Complexity, 2012