bluuebunny/crossref_metadata_2025 huggingface dataset:
Water distribution system vulnerability analysis using weighted and directed network models
Authors: Yazdani Alireza , Jeffrey Paul
Published: May 2012

The reliability and robustness against failures of networked water distribution systems are central tenets of water supply system design and operation. The ability of such networks to continue to supply water when components are damaged or fail is dependent on the connectivity of the network and the role and location of the individual components. This paper employs a set of advanced network analysis techniques to study the connectivity of water distribution systems, its relationship with system robustness, and susceptibility to damage. Water distribution systems are modeled as weighted and directed networks by using the physical and hydraulic attributes of system components. A selection of descriptive measurements is utilized to quantify the structural properties of benchmark systems at both local (component) and global (network) scales. Moreover, a novel measure of component criticality, the demand‐adjusted entropic degree, is proposed to support identification of critical nodes and their ranking according to failure impacts. The application and value of this metric is demonstrated through two case study networks in the USA and UK. Discussion focuses on the potential for gradual evolution of abstract graph‐based tools and techniques to more practical network analysis methods, where a theoretical framework for the analysis of robustness and vulnerability of water distribution networks to better support planning and management decisions is presented.
Device model for electronic processes at organic/organic interfaces
Authors: Liu Feilong , Paul Ruden P. , Campbell Ian. H. , Smith Darryl L.
Published: May 2012

Interfaces between different organic materials can play a key role in determining organic semiconductor device characteristics. Here, we present a physics-based one-dimensional model with the goal of exploring critical processes at organic/organic interfaces. Specifically, we envision a simple bilayer structure consisting of an electron transport layer (ETL), a hole transport layer (HTL), and the interface between them. The model calculations focus on the following aspects: (1) the microscopic physical processes at the interface, such as exciton formation/dissociation, exciplex formation/dissociation, and geminate/nongeminate recombination; (2) the treatment of the interface parameters and the discretization method; and (3) the application of this model to different devices, such as organic light emitting diodes and photovoltaic cells. At the interface, an electron on an ETL molecule can interact with a hole on an adjacent HTL molecule and form an intermolecular excited state (exciplex). If either the electron or the hole transfers across the interface, an exciton can be formed. The exciton may subsequently diffuse into the relevant layer and relax to the ground state. A strong effective electric field at the interface can cause excitons or exciplexes to dissociate into electrons in the ETL and holes in the HTL. Geminate recombination may occur when the Coulomb interaction between the electron and the hole generated at the interface by exciton dissociation causes the formation of a correlated state that then relaxes to the ground state. The relative impacts of the different processes on measurable macroscopic device characteristics are explored in our calculations by varying the corresponding kinetic coefficients. As it is the aim of this work to investigate effects associated with the organic/organic interface, its treatment in the numerical calculations is of critical importance. We model the interface as a continuous but rather sharp transition from the ETL to the HTL. The model is applied to different devices where different microscopic processes dominate. We discuss the results for an organic light emitting device with exciton or exciplex emission and for a photovoltaic device with or without geminate recombination. In the examples, C60 and tetracene parameters are used for the ETL and HTL materials, respectively.
A quantum generalization of intrinsic reaction coordinate using path integral centroid coordinates
Authors: Shiga Motoyuki , Fujisaki Hiroshi
Published: May 2012

We propose a generalization of the intrinsic reaction coordinate (IRC) for quantum many-body systems described in terms of the mass-weighted ring polymer centroids in the imaginary-time path integral theory. This novel kind of reaction coordinate, which may be called the “centroid IRC,” corresponds to the minimum free energy path connecting reactant and product states with a least amount of reversible work applied to the center of masses of the quantum nuclei, i.e., the centroids. We provide a numerical procedure to obtain the centroid IRC based on first principles by combining ab initio path integral simulation with the string method. This approach is applied to NH3 molecule and N2\documentclass[12pt]{minimal}\begin{document}${\rm H}_5^-$\end{document}H5− ion as well as their deuterated isotopomers to study the importance of nuclear quantum effects in the intramolecular and intermolecular proton transfer reactions. We find that, in the intramolecular proton transfer (inversion) of NH3, the free energy barrier for the centroid variables decreases with an amount of about 20% compared to the classical one at the room temperature. In the intermolecular proton transfer of N2\documentclass[12pt]{minimal}\begin{document}${\rm H}_5^-$\end{document}H5−, the centroid IRC is largely deviated from the “classical” IRC, and the free energy barrier is reduced by the quantum effects even more drastically.
Coexistence of free holes and electrons in InN:Mg with In- and N-growth polarities
Authors: Dmowski L. H. , Baj M. , Konczewicz L. , Suski T. , Maude D. K. , Grzanka S. , Wang X. Q. , Yoshikawa A.
Published: May 2012

The coexistence of two types of carriers (free electrons and free holes) in InN:Mg and their competition is demonstrated by the temperature and magnetic-field-induced change of the sign of thermopower (α) as well as the maximum entropy mobility spectrum analysis. The results confirm the existence of alternative carrier channels in addition to the n-type surface inversion layer and p-type bulk. They also show that In-polarity can be propitious for occurrence of p-type conductivity.
Natural time analysis of the Centennial Earthquake Catalog
Authors: Sarlis N. V. , Christopoulos S.-R. G.
Published: May 2012

By using the most recent version (1900–2007) of the Centennial Earthquake Catalog, we examine the properties of the global seismicity. Natural time analysis reveals that the fluctuations of the order parameter κ1 of seismicity exhibit for at least three orders of magnitude a characteristic feature similar to that of the order parameter for other equilibrium or non-equilibrium critical systems—including self-organized critical systems. Moreover, we find non-trivial magnitude correlations for earthquakes of magnitude greater than or equal to 7.
General stability result for viscoelastic wave equations
Authors: Mustafa Muhammad I. , Messaoudi Salim A.
Published: May 2012

In this paper, we consider a viscoelastic equation and establish an explicit and general decay rate result without imposing restrictive assumptions on the behavior of the relaxation function at infinity. Our result allows a wider class of relaxation functions and improves earlier results in the literature.
Non-orthogonal Wigner-like mapping
Authors: Sainz Isabel , Roa Luis , Klimov A. B.
Published: May 2012

We have developed a general method for construction of Wigner-like mapping to the phase-space associated with a non-orthogonal set of mutually unbiased equally separated bases. Explicit expressions of the Wigner functions in terms of measurements in non-orthogonal bases are given and the limit cases are analyzed.
Bandgap and band discontinuity in wurtzite/zincblende GaAs homomaterial heterostructure
Authors: Gurwitz Ron , Tavor Asa , Karpeles Liran , Shalish Ilan , Yi Wei , Seryogin Georgiy , Narayanamurti Venkatesh
Published: May 2012

A wurtzite GaAs epilayer grown on a zincblende GaAs substrate by metalorganic chemical vapor deposition is studied by surface photovoltage spectroscopy. The wurtzite structure of the epilayer is disclosed by scanning electron microscope images of surface pits, where the pits are seen to change their structure from a rectangular into a hexagonal shape. The wurtzite phase is also revealed in x-ray diffraction showing a 〈0002〉 diffraction alongside the main (200) diffraction, suggesting a “c” lattice constant of 0.668 nm. A comparison of room temperature surface photovoltage spectra taken from the epilayer sample and from an epilayer-etched substrate suggests a type II heterostructure with valence band difference of about 15 meV and bandgap difference of about 70 meV between the zincblende and the wurtzite GaAs polytypes.
High quality factor AlN nanocavities embedded in a photonic crystal waveguide
Authors: Sam-Giao D. , Néel D. , Sergent S. , Gayral B. , Rashid M. J. , Semond F. , Duboz J. Y. , Mexis M. , Guillet T. , Brimont C. , David S. , Checoury X. , Boucaud P.
Published: May 2012

We present a spectroscopic study of nanocavities obtained by small modifications of a W1 waveguide in an AlN photonic crystal membrane. The AlN film containing GaN quantum dots is grown on silicon. The photonic crystal structure is defined by e-beam lithography and etched by inductively coupled plasma reactive ion etching, while the membrane is released by selective etching of the silicon substrate. The room temperature photoluminescence of the embedded quantum dots reveals the existence of even-symmetry and odd-symmetry confined cavity modes and guided modes. Cavity mode quality factors up to 4400 at 395 nm and 2300 at 358 nm are obtained.
Enhancement of x-rays generated by a guided laser wakefield accelerator inside capillary tubes
Authors: Ju J. , Svensson K. , Döpp A. , Ferrari H. E. , Cassou K. , Neveu O. , Genoud G. , Wojda F. , Burza M. , Persson A. , Lundh O. , Wahlström C.-G. , Cros B.
Published: May 2012

Electrons accelerated in the nonlinear regime in a laser wakefield accelerator experience transverse oscillations inside the plasma cavity, giving rise to ultra-short pulsed x-rays, also called the betatron radiation. We show that the fluence of x-ray can be enhanced by more than one order of magnitude when the laser is guided by a 10 mm long capillary tube instead of interacting with a 2 mm gas jet. X-rays with a synchrotron-like spectrum and associated critical energy ∼5 keV, with a peak brightness of ∼1×1021 ph/s/mm2/mrad2/0.1%BW, were achieved by employing 16 TW laser pulses.
Extremely low surface recombination velocities in black silicon passivated by atomic layer deposition
Authors: Otto Martin , Kroll Matthias , Käsebier Thomas , Salzer Roland , Tünnermann Andreas , Wehrspohn Ralf B.
Published: May 2012

We investigate the optical and opto-electronic properties of black silicon (b-Si) nanostructures passivated with Al2O3. The b-Si nanostructures significantly improve the absorption of silicon due to superior anti-reflection and light trapping properties. By coating the b-Si nanostructures with a conformal layer of Al2O3 by atomic layer deposition, the surface recombination velocity can be effectively reduced. We show that control of plasma-induced subsurface damage is equally important to achieve low interface recombination. Surface recombination velocities of Seff<13 cm/s have been measured for an optimized structure which, like the polished reference, exhibits lifetimes in the millisecond range.
Broadband transmission enhancement of acoustic waves through a hybrid grating
Authors: Qiu Chunyin , Hao Rui , Li Feng , Xu Shengjun , Liu Zhengyou
Published: May 2012

We report an anomalous transmission enhancement of acoustic waves through a hybrid grating. The fundamental physics behind this phenomenon can be captured well by the improved impedance matching between the hybrid grating and the background fluid. This type of acoustic transparency is broadband and can be robust against the incident angle, which is drastically different from the previously reported mechanisms that are closely related with resonances. Potential applications of this effect can be anticipated in ultrasonic devices.
Nanoscale quantification of octahedral tilts in perovskite films
Authors: Hwang Jinwoo , Zhang Jack Y. , Son Junwoo , Stemmer Susanne
Published: May 2012

NiO6-octahedral tilts in ultrathin LaNiO3 films were studied using position averaged convergent beam electron diffraction (PACBED) in scanning transmission electron microscopy. Both the type and magnitude of the octahedral tilts were determined by comparing PACBED experiments to frozen phonon multislice simulations. It is shown that the out-of-plane octahedral tilt of an epitaxial film under biaxial tensile stress (0.78% in-plane tensile strain) increases by ∼20%, while the in-plane rotation decreases by ∼80%, compared to the unstrained bulk material.
Prediction of mortality and conception rates of beef breeding cattle in northern Australia
Authors: Mayer D. G. , McKeon G. M. , Moore A. D.
Published: May 2012

In current simulation packages for the management of extensive beef-cattle enterprises, the relationships for the key biological rates (namely conception and mortality) are quite rudimentary. To better estimate these relationships, cohort-level data covering 17 100 cow-years from six sites across northern Australia were collated and analysed. Further validation data, from 7200 cow-years, were then used to test these relationships. Analytical problems included incomplete and non-standardised data, considerable levels of correlation among the ‘independent’ variables, and the close similarity of alternate possible models. In addition to formal statistical analyses of these data, the theoretical equations for predicting mortality and conception rates in the current simulation models were reviewed, and then reparameterised and recalibrated where appropriate. The final models explained up to 80% of the variation in the data. These are now proposed as more accurate and useful models to be used in the prediction of biological rates in simulation studies for northern Australia.
Prevalence of mimosine and DHP toxicity in cattle grazing Leucaena leucocephala pastures in Queensland, Australia
Authors: Dalzell S. A. , Burnett D. J. , Dowsett J. E. , Forbes V. E. , Shelton H. M.
Published: May 2012

A postal survey of the level of awareness of leucaena toxicity and an on-farm study of the toxicity status of Queensland cattle herds grazing leucaena were conducted to investigate the prevalence of mimosine and dihydroxypyridine (DHP) toxicity in Queensland. In total, 195 of 356 graziers surveyed responded to the postal survey. Sixty-three percent had inoculated their cattle with in vitro Synergistes jonesii inoculum (produced in an anaerobic fermenter) and 30% of these had inoculated more than once. The remainder used inappropriate procedures. Many graziers (43%) had occasionally observed toxicity symptoms of hair loss and poor animal growth rates. In the on-farm study, the toxicity status of 385 animals in 44 individually managed herds on 36 properties was determined by urine analysis of mimosine and DHP concentrations. No animals were experiencing mimosine toxicity, based on low concentrations of this compound found in the urine. Using the criterion that average herd urine concentrations of DHP >100 μg/mL was indicative of subclinical toxicity, 48% of herds were exposed to subclinical toxicity due to dominant 3,4-DHP (21%) or dominant 2,3-DHP (27%) toxicity; many of these herds had been inoculated with S. jonesii and were thought to be protected. The finding that 27% of herds were excreting high concentrations of 2,3-DHP was unexpected. Statistical analysis of herd-management data revealed that the method used by graziers to inoculate their herds was significantly (P < 0.05) but weakly linked to herd protection status. It was concluded that subclinical 3,4-DHP and 2,3-DHP toxicity remains a problem in Queensland and is likely to be limiting animal production in a significant number of cattle grazing leucaena-grass pastures.
Remote activation of biomolecules in deep tissues using near-infrared-to-UV upconversion nanotransducers
Authors: Jayakumar Muthu Kumara Gnanasammandhan , Idris Niagara Muhammad , Zhang Yong
Published: May 2012

Controlled activation or release of biomolecules is very crucial in various biological applications. Controlling the activity of biomolecules have been attempted by various means and controlling the activity by light has gained popularity in the past decade. The major hurdle in this process is that photoactivable compounds mostly respond to UV radiation and not to visible or near-infrared (NIR) light. The use of UV irradiation is limited by its toxicity and very low tissue penetration power. In this study, we report the exploitation of the potential of NIR-to-UV upconversion nanoparticles (UCNs), which act as nanotransducers to absorb NIR light having high tissue penetration power and negligible phototoxicity and emit UV light locally, for photoactivation of caged compounds and, in particular, used for photo-controlled gene expression. Both activation and knockdown of GFP was performed in both solution and cells, and patterned activation of GFP was achieved successfully by using upconverted UV light produced by NIR-to-UV UCNs. In-depth photoactivation through tissue phantoms and in vivo activation of caged nucleic acids were also accomplished. The success of this methodology has defined a unique level in the field of photo-controlled activation and delivery of molecules.
Lesion processing by a repair enzyme is severely curtailed by residues needed to prevent aberrant activity on undamaged DNA
Authors: Maiti Atanu , Noon Muhammad S. , MacKerell Alexander D. , Pozharski Edwin , Drohat Alexander C.
Published: May 2012

DNA base excision repair is essential for maintaining genomic integrity and for active DNA demethylation, a central element of epigenetic regulation. A key player is thymine DNA glycosylase (TDG), which excises thymine from mutagenic G·T mispairs that arise by deamination of 5-methylcytosine (mC). TDG also removes 5-formylcytosine and 5-carboxylcytosine, oxidized forms of mC produced by Tet enzymes. Recent studies show that the glycosylase activity of TDG is essential for active DNA demethylation and for embryonic development. Our understanding of how repair enzymes excise modified bases without acting on undamaged DNA remains incomplete, particularly for mismatch glycosylases such as TDG. We solved a crystal structure of TDG (catalytic domain) bound to a substrate analog and characterized active-site residues by mutagenesis, kinetics, and molecular dynamics simulations. The studies reveal how TDG binds and positions the nucleophile (water) and uncover a previously unrecognized catalytic residue (Thr197). Remarkably, mutation of two active-site residues (Ala145 and His151) causes a dramatic enhancement in G·T glycosylase activity but confers even greater increases in the aberrant removal of thymine from normal A·T base pairs. The strict conservation of these residues may reflect a mechanism used to strike a tolerable balance between the requirement for efficient repair of G·T lesions and the need to minimize aberrant action on undamaged DNA, which can be mutagenic and cytotoxic. Such a compromise in G·T activity can account in part for the relatively weak G·T activity of TDG, a trait that could potentially contribute to the hypermutability of CpG sites in cancer and genetic disease.
Synthesis and Photocatalytic Property of ZnO/TiO2 Inverse Opals Films with Controllable Composition and Topology
Authors: Xu Jiao , Yang Bei-fang , Fu Zheng-ping , Wen Mei-wang , Zhao Yong-xun
Published: May 2012

A novel method to fabricate composition- and topology-controlled ZnO/TiO2 inverse opals (IO) films using a positive sacrificial ZnO IO template has been developed. This method includes a two-step process, preparation of ZnO IO by a simple electrochemical deposition using a self-assembly polystyrene colloidal crystal template and preparation of ZnO/TiO2 IO by a liquid phase deposition (LPD) process at room temperature. The composition and topology of ZnO/TiO2 IO can be easily controlled by changing the duration of the LPD. After 20 min LPD process, a ZnO/TiO2 composite IO with non-close-packed face-centered cubic air sphere array was obtained. Prolonging the duration to 60 min, a pure TiO2 IO (TIO-LPD60) with obviously thickened walls was formed. The formation mechanism for the compositional and topological variation was discussed. A preliminary study on UV photocatalytic property of the samples for degradation of methylene blue reveals that the composition and topology significantly influenced the photocatalytic activity of the IO film. The ZnO/TiO2 composite IO demonstrates a higher degree of activity than both pure ZnO and pure TiO2 IO, although they have a similar IO wall thickness. Moreover, with increasing IO wall thickness from ∼52 nm to ∼90 nm, TIO-LPD60 exhibits the highest level of photocatalytic performance.
Obscurin and KCTD6 regulate cullin-dependent small ankyrin-1 (sAnk1.5) protein turnover
Authors: Lange Stephan , Perera Sue , Teh Phildrich , Chen Ju
Published: May 2012

Protein turnover through cullin-3 is tightly regulated by posttranslational modifications, the COP9 signalosome, and BTB/POZ-domain proteins that link cullin-3 to specific substrates for ubiquitylation. In this paper, we report how potassium channel tetramerization domain containing 6 (KCTD6) represents a novel substrate adaptor for cullin-3, effectively regulating protein levels of the muscle small ankyrin-1 isoform 5 (sAnk1.5).

Binding of sAnk1.5 to KCTD6, and its subsequent turnover is regulated through posttranslational modification by nedd8, ubiquitin, and acetylation of C-terminal lysine residues. The presence of the sAnk1.5 binding partner obscurin, and mutation of lysine residues increased sAnk1.5 protein levels, as did knockdown of KCTD6 in cardiomyocytes. Obscurin knockout muscle displayed reduced sAnk1.5 levels and mislocalization of the sAnk1.5/KCTD6 complex. Scaffolding functions of obscurin may therefore prevent activation of the cullin-mediated protein degradation machinery and ubiquitylation of sAnk1.5 through sequestration of sAnk1.5/KCTD6 at the sarcomeric M-band, away from the Z-disk–associated cullin-3. The interaction of KCTD6 with ankyrin-1 may have implications beyond muscle for hereditary spherocytosis, as KCTD6 is also present in erythrocytes, and erythrocyte ankyrin isoforms contain its mapped minimal binding site.
Electron tomography of late stages of FcRn-mediated antibody transcytosis in neonatal rat small intestine
Authors: Ladinsky Mark S. , Huey-Tubman Kathryn E. , Bjorkman Pamela J.
Published: May 2012

The neonatal Fc receptor (FcRn) transports maternal immunoglobulin (IgG) across epithelia to confer passive immunity to mammalian young. In newborn rodents, FcRn transcytoses IgG from ingested milk across the intestinal epithelium for release into the bloodstream. We used electron tomography to examine FcRn transport of Nanogold-labeled Fc (Au-Fc) in neonatal rat jejunum, focusing on later aspects of transport by chasing Au-Fc before fixation. We observed pools of Au-Fc in dilated regions of the lateral intercellular space (LIS), likely representing exit sites where Au-Fc accumulates en route to the blood. Before weaning, the jejunum functions primarily in IgG transport and exhibits unusual properties: clathrin-rich regions near/at the basolateral LIS and multivesicular bodies (MVBs) expressing early endosomal markers. To address whether these features are related to IgG transport, we examined LIS and endocytic/transcytotic structures from neonatal and weaned animals. Weaned samples showed less LIS-associated clathrin. MVBs labeled with late endosomal/lysosomal markers were smaller than their neonatal counterparts but contained 10 times more internal compartments. These results are consistent with hypotheses that clathrin-rich basolateral regions in neonatal jejunum are involved in IgG exocytosis and that MVBs function in IgG transport while FcRn is expressed but switch to degradative functions after weaning, when the jejunum does not express FcRn or transport IgG.
Long‐term Care Financing in the United States: Sources and Institutions
Authors: Frank Richard G.
Published: May 2012

This paper reviews the financing of long‐term services and supports (LTSS) in the United States. I characterize existing payment arrangements as incomplete insurance. The paper organizes existing literature on U.S. financing of LTSS and uses it to analyze the economic, policy and behavioral forces that underpin the observed equilibrium. I assess several sources of market failure and consider policy directions that are viable within the U.S. political environment.
Reforming Long‐term Care Funding Arrangements in England: International Lessons
Authors: Fernandez Jose‐Luis , Forder Julien
Published: May 2012

Ever since the failed 1999 Royal Commission, England has been attempting to reform its long‐term care funding system. More than a decade later, significant changes to the means tested arrangements are yet to be introduced, whilst the pressure to achieve long‐term reform mounts linked to increases in public expenditure and ever growing demand for better services. This paper examines the pros and cons of alternative options for reforming the English long‐term care funding arrangements by examining the rationale for and consequences of the recent long‐term care developments in Germany, Japan and France. In particular, the paper examines the implications of the reform options adopted in the different countries examined for equity and efficiency in the use of long‐term care resources and for the sustainability of the long‐term care system as a whole.
The Relationship between Seats and Votes in Multiparty Systems
Authors: Linzer Drew A.
Published: May 2012

The relationship between a party's popular vote share and legislative seat share—its seats—votesswing ratio—is a key characteristic of democratic representation. This article introduces a general approach to estimating party-specific swing ratios in multiparty legislative elections, given results from only a single election. I estimate the joint density of party vote shares across districts using a finite mixture model for compositional data and then computationally evaluate this distribution to produce parties' expected change in legislative seats for plausible changes in their vote share. The method easily extends to systems with any number of parties, employing both majoritarian and proportional electoral rules. Applications to legislative elections in the United States, United Kingdom, Canada, and Botswana demonstrate how parties' swing ratios vary both within countries and over time, indicating that parties under majoritarian electoral rules are subject to unique and possibly divergent geographic—political constraints.
Cannulation of the Middle Cardiac Vein during MICS
Authors: Pantin Enrique J. , Kraidin Jonathan L. , Ginsberg Steven H. , Denny John T. , Solina Alann R.
Published: May 2012

Coronary sinus cannulation for retrograde cardioplegia administration during cardiac surgery is common practice. Several of the cannulas that are placed by the cardiac surgeon on open procedures are now placed by the cardiac anesthesiologist during minimally invasive cardiac surgery, including the coronary sinus catheter. The understanding of the cardiac venous anatomy is very important during coronary sinus catheter placement. We present a case where a percutaneously placed coronary sinus catheter was inadvertently placed into the middle cardiac vein but detected with the use of fluoroscopy.
Surgical Treatment of Isolated (Lone) Atrial Fibrillation with Gemini-S Ablation and Left Atrial Appendage Excision (GALAXY Procedure)
Authors: Doty John R. , Clayson Stephen E.
Published: May 2012

Objective

Surgical ablation with radiofrequency is a safe and effective treatment for atrial fibrillation. Recent advances in instrumentation have allowed for the application of bipolar radiofrequency through a minimally invasive approach using small bilateral thoracotomies for pulmonary vein isolation, destruction of autonomic ganglia, and excision of the left atrial appendage (GALAXY procedure).

Methods

Thirty-two patients underwent surgical ablation of atrial fibrillation with the GALAXY procedure over a 43-month period. Data were collected in a prospective manner during hospitalization and at 1-, 3-, 6-, and 12-month intervals for rhythm, medications, and subsequent interventions.

Results

There were no operative mortality, no myocardial infarction, and no stroke. One patient required reexploration for bleeding. Mean follow-up was 28 months (range, 4–43 months). Freedom from atrial fibrillation at 12 and 24 months, respectively, was 90% and 67% for patients with paroxysmal fibrillation and 80% and 63% for patients with persistent atrial fibrillation. Of the patients who were not in sinus rhythm, four reverted to atrial fibrillation and two reverted to atrial flutter.

Conclusions

The GALAXY procedure is a safe and effective, minimally invasive method for treatment of isolated (lone) atrial fibrillation. The operation provides excellent short-term freedom from atrial fibrillation and should be considered in patients with isolated paroxysmal atrial fibrillation.
Mechanostereochemistry and the mechanical bond
Authors: Barin Gokhan , Forgan Ross S. , Stoddart J. Fraser
Published: May 2012

The chemistry of mechanically interlocked molecules (MIMs), in which two or more covalently linked components are held together by
mechanical bonds
, has led to the coining of the term
mechanostereochemistry
to describe a new field of chemistry that embraces many aspects of MIMs, including their syntheses, properties, topologies where relevant and functions where operative. During the rapid development and emergence of the field, the synthesis of MIMs has witnessed the forsaking of the early and grossly inefficient statistical approaches for template-directed protocols, aided and abetted by molecular recognition processes and the tenets of self-assembly. The resounding success of these synthetic protocols, based on templation, has facilitated the design and construction of artificial molecular switches and machines, resulting more and more in the creation of integrated functional systems. This review highlights (i) the range of template-directed synthetic methods being used currently in the preparation of MIMs; (ii) the syntheses of topologically complex knots and links in the form of stable molecular compounds; and (iii) the incorporation of bistable MIMs into many different device settings associated with surfaces, nanoparticles and solid-state materials in response to the needs of particular applications that are perceived to be fair game for mechanostereochemistry.
Silencing of endogenous envelope genes in human choriocarcinoma cells shows that envPb1 is involved in heterotypic cell fusions
Authors: Aagaard Lars , Bjerregaard Bolette , Kjeldbjerg Anders L. , Pedersen Finn Skou , Larsson Lars-Inge , Rossi John J.
Published: May 2012

Syncytin-1 and envPb1 are two conserved envelope genes in the human genome encoded by single loci from the HERV-W and -Pb families, respectively. To characterize the role of these envelope proteins in cell–cell fusion, we have developed lentiviral vectors that express short hairpin RNAs for stable knockdown of syncytin-1 and envPb1. Analysis of heterotypic fusion activity between trophoblast-derived choriocarcinoma BeWo cells, in which syncytin-1 and envPb1 are specifically silenced, and endothelial cells demonstrated that both syncytin-1 and envPb1 are important to fusion. The ability to fuse cells makes syncytin-1 and envPb1 attractive candidate molecules in therapy against cancer. Our available vectors may help eventually to decipher roles for these genes in human health and/or disease.
Poplar Extrafloral Nectaries: Two Types, Two Strategies of Indirect Defenses against Herbivores
Authors: Escalante-Pérez María , Jaborsky Mario , Lautner Silke , Fromm Jörg , Müller Tobias , Dittrich Marcus , Kunert Maritta , Boland Wilhelm , Hedrich Rainer , Ache Peter
Published: May 2012

Many plant species grow extrafloral nectaries and produce nectar to attract carnivore arthropods as defenders against herbivores. Two nectary types that evolved with Populus trichocarpa (Ptr) and Populus tremula × Populus tremuloides (Ptt) were studied from their ecology down to the genes and molecules. Both nectary types strongly differ in morphology, nectar composition and mode of secretion, and defense strategy. In Ptt, nectaries represent constitutive organs with continuous merocrine nectar flow, nectary appearance, nectar production, and flow. In contrast, Ptr nectaries were found to be holocrine and inducible. Neither mechanical wounding nor the application of jasmonic acid, but infestation by sucking insects, induced Ptr nectar secretion. Thus, nectaries of Ptr and Ptt seem to answer the same threat by the use of different mechanisms.
Lithium bis(2-methyllactato)borate monohydrate
Authors: Allen Joshua L. , Paillard Elie , Boyle Paul D. , Henderson Wesley A.
Published: May 2012

The title compound {systematic name: poly[[aqualithium]-μ-3,3,8,8-tetramethyl-1,4,6,9-tetraoxa-5λ4-borataspiro[4.4]nonane-2,7-dione]}, [Li(C8H12BO6)(H2O)]
n
(LiBMLB), forms a 12-membered macrocycle, which lies across a crystallographic inversion center. The lithium cations are pseudo-tetrahedrally coordinated by three methyllactate ligands and a water molecule. The asymmetric units couple across crystallographic inversion centers, forming the 12-membered macrocycles. These macrocycles, in turn, cross-link through the Li+ cations, forming an infinite polymeric structure in two dimensions parallel to (101).
5-(4-Methylphenyl)-1,3,4-oxadiazol-2-amine
Authors: Zheng Juan , Li Wen-juan , Song Manman , Xu Yan
Published: May 2012

In the crystal structure of the title compound, C9H9N3O, adjacent molecules are linked through N—H...N hydrogen bonds into a three-dimensional network.
2,4-Dichloro-6-({2-[(3,5-dichloro-2-hydroxybenzylidene)amino]ethyl}iminomethyl)phenol
Authors: Ourari Ali , Baameur Lotfi , Bouacida Sofiane , Gilles Bouet , Magali Allain
Published: May 2012

The title molecule, C16H12Cl4N2O2, lies about an inversion center. The symmetry-unique part of the molecule contains an intramolecular O—H...N hydrogen bond. In the crystal, molecules are arranged in corrugated layers parallel to (-101). Weak π–π stacking interactions, with a centroid–centroid diatance of 3.7923 (13) Å, are present.
9-Aminoacridinium bis(pyridine-2,6-dicarboxylato-κ3
O
2,N,O
6)ferrate(III) tetrahydrate
Authors: Mirzaei Masoud , Eshtiagh-Hosseini Hossein , Eydizadeh Ehsan , Yousefi Zakieh , Molčanov Krešimir
Published: May 2012

The asymmetric unit of the title compound, (C13H11N2)[Fe(C7H3NO4)2]·4H2O, contains a 9-aminoacridinium cation, one anionic complex and four uncoordinated water molecules. In the anionic complex, the FeIII ion is six-coordinated by two almost perpendicular [dihedral angle = 88.78 (7)°] pyridine-2,6-dicarboxylate ligands in a distorted octahedral geometry. In the crystal, anions are connected into chains along [10-1] by weak C—H...O interactions, which create ten-membered hydrogen-bonded R
2
2(10) rings. These chains are linked by three-membered water clusters. The final three-dimensional network is constructed by numerous intermolecular O—H...O and N—H...O interactions.
4-Cyanopyridinium dihydrogen phosphate–isonicotinonitrile–phosphoric acid (1/1/1)
Authors: Wang Ying-Chun
Published: May 2012

The asymmetric unit of the title compound, C6H5N2
+·H2PO4
−·C6H4N2·H3PO4, contains one 4-cyanopyridinium cation, one H2PO4
− anion, one independent isonicotinonitrile molecule and one independent H3PO4 molecule. The dihedral angle between the mean planes of the separate protonated and unprotonated pyridine rings is 9.93 (8)°. In the crystal, N—H...O and O—H...N hydrogen bonds and weak C—H...O and C—H...N intermolecular interactions connect the organic molecules into a two-dimensional network parallel to the ac plane. O—H...O hydrogen-bonding interactions involving the H2PO4
− anions and H3PO4 molecules provide additional support from the inorganic groups Weak π–π stacking interactions between the pyridine rings of neighbouring organic molecules [centroid–centroid distances = 3.711 (4) and 3.784 (2) Å] further link the layers into a three-dimensional network.
2-(4-Isopropyl-4-methyl-5-oxo-4,5-dihydro-1H-imidazol-2-yl)-5-methylnicotinic acid
Authors: Liu Li-Ping , Wang Xiao-Dan , Zhang Shuang , Gao Jin-Sheng
Published: May 2012

In the title herbicideh/phytocide, known as imazapic, C14H17N3O3, the pyridine and imidazole rings are almost coplanar [dihedral angle = 3.08 (5)°]. An intramolecular O—H...N hydrogen bond occurs. In the crystal, an N—H...O hydrogen bond links molecules into a chain parallel to [010].
Tris[(2E)-1,3-bis(4-chlorophenyl)triaz-2-en-1-ido-κ2
N
1,N
3]cobalt(III)
Authors: Yu Gang , Zhan Shu-Zhong , Ng Seik Weng
Published: May 2012

Molecules of the title compound, [Co(C12H8Cl2N3)3], lie on a threefold rotation axis. The tris-N,N′-chelated CoIII atom, which is located on the threefold rotation axis, shows a distorted octahedral coordination.
[2-Formyl-4-methyl-6-({2-[2-(4-nitrobenzylamino)ethylamino]ethylimino}methyl)phenolato]nickel(II) perchlorate
Authors: Wang Yang , Mao Jia-Wei , Song Hui-Ting , Zhou Hong
Published: May 2012

In the unsymmetrical title complex, [Ni(C20H23N4O4)]ClO4, the coordination geometry for the NiII atom can be described as square planar. The aromatic rings in the two ligands are almost vertical, with a dihedral angle of 85.3°. In the crystal, cations and anions are linked by weak C(N)—H...O hydrogen bonding.
The interactive nutrient and water effects on vegetation biomass at two African savannah sites with different mean annual precipitation
Authors: Wang Lixin , Katjiua Mutjinde , D'Odorico Paolo , Okin Gregory S.
Published: May 2012

Savannahs cover more than 40% of Africa and provide a variety of important ecosystem services. Their productivity is constrained by disturbance and limiting resources. In southern Africa, fine‐leaf savannahs typical of arid environments are known for being richer in nutrients than broad‐leaf mesic savannahs. However, despite numerous recent studies on the dynamics of southern African savannahs, the interplay between water and nutrient limitations remains poorly investigated in these systems. To better understand the interactions between water, nutrients (N and P in this manuscript) and grazing on the productivity of grasses and trees in fine‐leaf savannah ecosystems, a fertilization experiment with controlled grazing was conducted at two sites with different mean annual rainfall in Namibia. The experiment demonstrated that the vegetation at the drier site may not be nutrient‐limited (N, P or N + P). At the wetter site, however, vegetation showed significant response to nutrient addition. Grasses exhibited N limitation and trees exhibited P limitation. This experiment also showed that grazing reduces the overall grass biomass, but may not modify the response to nutrient treatments. The results indicated a switch from water to nutrient limitation between dry and wet sites and demonstrated different tree and grass responses to nutrient additions.
Pioglitazone and bladder cancer: a propensity score matched cohort study
Authors: Wei Li , MacDonald Thomas M. , Mackenzie Isla S.
Published: May 2012

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Pioglitazone is mainly used in combination with diet and exercise and other anti‐diabetic medications to treat type 2 diabetes mellitus.

• Long term use of pioglitazone (>24 months of therapy) may be associated with an increased risk of bladder cancer.

WHAT THIS STUDY ADDS

• In this study population, pioglitazone does not appear to be significantly associated with an increased risk of bladder cancer in patients with type 2 diabetes.

AIM To examine whether exposure to pioglitazone use is associated with increased incidence of bladder cancer in patients with type 2 diabetes mellitus.

METHOD A cohort study was done in the General Practice Research Database (GPRD) between 2001 and 2010. Two hundred and seven thousand seven hundred and fourteen patients aged ≥40 years with type 2 diabetes were studied (23 548 exposed to pioglitazone and 184 166 exposed to other antidiabetic medications but not pioglitazone). The association between pioglitazone and risk of bladder cancer was assessed by a Cox regression model. A propensity score matched analysis was done in a group of patients without missing baseline characteristics data.

RESULTS Sixty‐six and 803 new cases of bladder cancer occurred in the pioglitazone and other group, respectively (rates of 80.2 (95% CI 60.8, 99.5) and 81.8 (95% CI 76.2, 87.5) per 100 000 person‐years respectively). Pioglitazone did not increase the risk of bladder cancer significantly compared with the other antidiabetic drugs treatment group, (adjusted hazard ratio (HR), 1.16, 95% CI 0.83, 1.62). In a matched propensity score analysis in which both groups had similar baseline characteristics (17 249 patients in each group), the adjusted HR was 1.22 (95% CI 0.80, 1.84).

CONCLUSION The results suggest that pioglitazone may not be significantly associated with an increased risk of bladder cancer in patients with type 2 diabetes.
Long‐term follow‐up of myelodysplastic syndrome patients with moderate/severe anaemia receiving human recombinant erythropoietin + 13‐cis‐retinoic acid and dihydroxylated vitamin D3: independent positive impact of erythroid response on survival
Authors: Crisà Elena , Foli Cristina , Passera Roberto , Darbesio Antonella , Garvey Kimberly B. , Boccadoro Mario , Ferrero Dario
Published: May 2012

We previously reported a 60% erythroid response rate with recombinant erythropoietin + 13‐cis retinoic acid + dihydroxylated vitamin D3 in 63 elderly myelodysplastic patients (median age 75 years) with unfavourable features for response to erythropoietin alone [70% transfusion‐dependent, 35% refractory anaemia with ring sideroblasts/refractory anaemia with excess of blasts type 1 (RAEB1), 70% with International Prognostic Scoring System (IPSS) Intermediate‐1 or ‐2]. This report updates that case study at a 7‐year follow‐up, and compared the impact on overall survival of erythroid response to known prognostic factors. The erythroid response duration (median 17 months; 22 in non‐RAEB patients, with 20% patients in response after 6 years of therapy) was longer than in most studies with erythropoietin alone. Overall survival (median 55 months in non‐RAEB, 15 in RAEB1 patients) was negatively affected by RAEB1 diagnosis, IPSS and WPSS intermediate scores and transfusion‐dependence. In the multivariate analysis, erythroid response maintained an independent positive impact on survival, particularly in non‐RAEB patients in the first 3 years from diagnosis (90% survival compared to 50% of non‐responders). In conclusion, the long‐term follow‐up confirmed the achievement, by our combined treatment, of fairly long‐lasting erythroid response in the majority of MDS patients with unfavourable prognostic features for response to erythropoietin: this translated in a survival benefit that was independent from other prognostic features.
Bendamustine plus mitoxantrone for relapsed/refractory chronic lymphocytic leukaemia (CLL): results of a multicentre phase II study of the German CLL Study Group (GCLLSG)
Authors: Köppler Hubert , Fuss Harald , Hurtz Hans J. , Knigge Owe , Losem Christoph , Reschke Daniel , Schmitz Stephan , Weide Rudolf , Weiß Johann , Hallek Michael ,   for the GCLLSG
Published: May 2012

The efficacy of bendamustine (50 mg/m², days 1–3) plus mitoxantrone (10 mg/m², day 1), every 28 days for up to four courses, was evaluated in a Phase II multicentre trial enrolling 59 patients with relapsed or refractory B‐cell chronic lymphocytic leukaemia (CLL). Major toxicities were grade 3/4 leucopenia, thrombocytopenia and infections in 42%, 12% and 12% of patients, respectively. Complete and partial response was achieved in 5/59 and 25/29 patients, respectively (overall response rate, 51%). Median time to progression was 22 months (range 1–49 + ) and median survival 27 months (range 0–49 + ). The combination of bendamustine and mitoxantrone is an active regime in relapsed or refractory CLL.
GSK3 inhibitor‐BIO regulates proliferation of female germline stem cells from the postnatal mouse ovary
Authors: Hu Y. , Bai Y. , Chu Z. , Wang J. , Wang L. , Yu M. , Lian Z. , Hua J.
Published: May 2012

Objective

It is widely believed that in most female mammalian neonates, all germ cells enter meiosis to form the primary oocyte at the end of foetal development, and as a result, the postnatal mammalian ovary harbours only a limited supply of oocytes that cannot be regenerated. However, this idea has been challenged by the discovery of the existence of female germline stem cells (FGSCs) in postnatal mammalian ovaries.

Materials and Methods

We have isolated ovarian GSCs from neonatal and adult mouse ovaries and expanded them in the same culture conditions as embryonic stem cells (ESCs).

Results

LIF and BIO were beneficial for formation of FGSC colonies. BIO promoted proliferation of FGSCs through activation of β‐catenin and up‐regulation of E‐cadherin. The FGSCs formed compact round colonies with unclear borders, maintained ESC characteristics and alkaline phosphatase (AP) activity, expressing germ‐cell markers‐Vasa, and stem‐cell markers: Oct4, Klf4, C‐myc, Nanog, CD49f, Sox2, CD133, SSEA1 and SSEA4. These cells had the ability to form embryoid bodies (EBs), which expressed specific markers for all three germ layers. Then we induced EBs to differentiate into neurons, cardiomyocytes, pancreatic cells and germ cells, which showed the expression of specific markers, β‐III‐tubulin, cardiac a‐actin, Pdx1 and Zps respectively.

Discussion and Conclusion

This study reveals the existence of FGSCs in postnatal mouse ovary with multipotent characteristics. BIO played an important role in regulation of proliferation and maintenance of the FGSCs. This could help provide a better understanding of causes of ovarian infertility, prevention and potential treatment of infertility.
Macrophage migration inhibitory factor deficiency protects pancreatic islets from cytokine-induced apoptosis in vitro
Authors: Stojanovic I , Saksida T , Nikolic I , Nicoletti F , Stosic-Grujicic S
Published: May 2012

During pathogenesis of diabetes, pancreatic islets are exposed to high levels of cytokines and other inflammatory mediators that induce deterioration of insulin-producing beta cells. Macrophage migration inhibitory factor (MIF) plays a key role in the onset and development of several immunoinflammatory diseases and also controls apoptotic cell death. Because the occurrence of apoptosis plays a pathogenetic role in beta cell death during type 1 diabetes development and MIF is expressed in beta cells, we explored the influence of MIF deficiency on cytokine-induced apoptosis in pancreatic islets. The results indicated clearly that elevated MIF secretion preceded C57BL/6 pancreatic islets death induced by interferon (IFN)-γ + tumour necrosis factor (TNF)-α + interleukin (IL)-1β. Consequently, MIF-deficient [MIF-knock-out (KO)] pancreatic islets or islet cells showed significant resistance to cytokine-induced death than those isolated from C57BL/6 mice. Furthermore, upon exposure to cytokines pancreatic islets from MIF-KO mice maintained normal insulin expression and produced less cyclooxygenase-2 (COX-2) than those from wild-type C57BL6 mice. The final outcome of cytokine-induced islet apoptosis in islets from wild-type mice was the activation of mitochondrial membrane pore-forming protein Bcl-2-associated X protein and effector caspase 3. In contrast, these apoptotic mediators remained at normal levels in islets from MIF-KO mice suggesting that MIF absence prevented initiation of the mitochondrial apoptotic pathway. Additionally, the protection from apoptosis was also mediated by up-regulation of prosurvival kinase extracellular-regulated kinase 1/2 in MIF-KO islets. These data indicate that MIF is involved in the propagation of pancreatic islets apoptosis probably via nuclear factor-κB and mitochondria-related proteins.