bluuebunny/crossref_metadata_2025 huggingface dataset:
Orbital-optimized third-order Møller-Plesset perturbation theory and its spin-component and spin-opposite scaled variants: Application to symmetry breaking problems
Authors: Bozkaya Uğur
Published: December 2011

In this research, orbital-optimized third-order Møller-Plesset perturbation theory (OMP3) and its spin-component and spin-opposite scaled variants (SCS-OMP3 and SOS-OMP3) are introduced. Using a Lagrangian-based approach, an efficient, quadratically convergent algorithm for variational optimization of the molecular orbitals (MOs) for third-order Møller-Plesset perturbation theory (MP3) is presented. Explicit equations for response density matrices, the MO gradient, and Hessian are reported in spin-orbital form. The OMP3, SCS-OMP3, and SOS-OMP3 approaches are compared with the second-order Møller-Plesset perturbation theory (MP2), MP3, coupled-cluster doubles (CCD), optimized-doubles (OD), and coupled-cluster singles and doubles (CCSD) methods. All these methods are applied to the \documentclass[12pt]{minimal}\begin{document}${\rm O}_{4} ^{+}$\end{document}O4+, O3, and seven diatomic molecules. Results demonstrate that the OMP3 and its variants provide significantly better vibrational frequencies than MP3, CCSD, and OD for the molecules where the symmetry-breaking problems are observed. For \documentclass[12pt]{minimal}\begin{document}${\rm O}_{4} ^{+}$\end{document}O4+, the OMP3 prediction, 1343 cm−1, for ω6 (b3u) mode, where symmetry-breaking appears, is even better than presumably more reliable methods such as Brueckner doubles (BD), 1194 cm−1, and OD, 1193 cm−1, methods (the experimental value is 1320 cm−1). For O3, the predictions of SCS-OMP3 (1143 cm−1) and SOS-OMP3 (1165 cm−1) are remarkably better than the more robust OD method (1282 cm−1); the experimental value is 1089 cm−1. For the seven diatomics, again the SCS-OMP3 and SOS-OMP3 methods provide the lowest average errors, |Δωe| = 44 and |Δωe| = 35 cm−1, respectively, while for OD, |Δωe| = 161 cm−1and CCSD |Δωe| = 106 cm−1. Hence, the OMP3 and especially its spin-scaled variants perform much better than the MP3, CCSD, and more robust OD approaches for considered test cases. Therefore, considering both the computational cost and the reliability, SCS-OMP3 and SOS-OMP3 appear to be the best methods for the symmetry-breaking cases, based on present application results. The OMP3 method offers certain advantages: it provides reliable vibrational frequencies in case of symmetry-breaking problems, especially with spin-scaling tricks, its analytic gradients are easier to compute since there is no need to solve the coupled-perturbed equations for the orbital response, and the computation of one-electron properties are easier because there is no response contribution to the particle density matrices. The OMP3 has further advantages over standard MP3, making it promising for excited state properties via linear response theory.
Large bandgaps of two-dimensional phononic crystals with cross-like holes
Authors: Wang Yan-Feng , Wang Yue-Sheng , Su Xiao-Xing
Published: December 2011

In this paper we study the bandgap properties of two-dimensional phononic crystals with cross-like holes using the finite element method. The influence of the geometry parameters of the holes on the bandgaps is discussed. In contrast to a system of square holes, which does not exhibits bandgaps if the symmetry of the holes is the same as that of the lattice, systems of cross-like holes show large bandgaps at lower frequencies. The bandgaps are significantly dependent upon the geometry (including the size, shape, and rotation) of the cross-like holes. The vibration modes of the bandgap edges are computed and analyzed in order to clarify the mechanism of the generation of the lowest bandgap. It is found that the generation of the lowest bangdap is a result of the local resonance of the periodically arranged lumps connected with narrow connectors. Spring-mass models are developed in order to predict the frequencies of the lower bandgap edges. The study in this paper is relevant to the optimal design of the bandgaps in light porous materials.
Microparticle trapping in an ultrasonic Bessel beam
Authors: Choe Youngki , Kim Jonathan W. , Shung K. Kirk , Kim Eun Sok
Published: December 2011

This paper describes an acoustic trap consisting of a multi-foci Fresnel lens on 127 μm thick lead zirconate titanate sheet. The multi-foci Fresnel lens was designed to have similar working mechanism to an Axicon lens and generates an acoustic Bessel beam, and has negative axial radiation force capable of trapping one or more microparticle(s). The fabricated acoustic tweezers trapped lipid particles ranging in diameter from 50 to 200 μm and microspheres ranging in diameter from 70 to 90 μm at a distance of 2 to 5 mm from the tweezers without any contact between the transducer and microparticles.
Probing the electrostatics of self-assembled monolayers by means of beveled metal-oxide-semiconductor structures
Authors: Kornblum Lior , Paska Yair , Rothschild Jonathan A. , Haick Hossam , Eizenberg Moshe
Published: December 2011

A method is proposed for characterization of the electrostatics of self-assembled monolayers (SAMs). The method is based on the extraction of the metal’s effective work function in metal-oxide-semiconductor capacitors, where the SAM is positioned at the metal-oxide interface. Hexyltrichlorosilane molecules assembled on SiO2 are used as a model system for this method. A band offset of 0.5 ± 0.15 eV is observed in the SAM sample when compared to a reference with no molecules. Spectroscopy is employed to confirm the presence of silane anchoring groups after metal deposition.
Ferromagnetic ZnO nanocrystals and Al-induced defects
Authors: Phadnis Chinmay , Inamdar Darshana Y. , Dubenko Igor , Pathak Arjun , Ali Naushad , Mahamuni Shailaja
Published: December 2011

ZnO nanocrystals (NCs) capped with polyvinyl pyrrolidone reveal room temperature ferromagnetism. Incorporation of Al3+-ions induce defects in ZnO NCs leading to quenching of excitonic luminescence of ZnO at the cost of an increase in the intensity of oxygen vacancy related emission. Photoluminescence excitation spectra exhibit an additional hump like feature attributed to Al-doping. Saturation magnetization of Al3+-doped ZnO NCs is the same as that of the undoped ZnO NCs. However, a remarkable decrease in the coercivity associated with change in the nature of M (T) curve and electron paramagnetic resonance signal with g = 1.96 is observed consequent to Al doping. The results provide direct evidence of the defects within the core of NCs that are responsible for the ferromagnetic ordering in the Al3+-doped ZnO. The M(T) curve unravels a typical exchange mechanism.
Nanoshells as a high-pressure gauge analyzed to 200 GPa
Authors: Van den Broeck Nick , Putteneers Katrijn , Tempere Jacques , Silvera Isaac F.
Published: December 2011

In this article, we present calculations that indicate that nanoshells can be used as a high-pressure gauge in diamond anvil cells (DACs). Nanoparticles have important advantages in comparison with the currently used ruby fluorescence gauge. Because of their small dimensions, they can be spread uniformly over a diamond surface without bridging between the two diamond anvils. Furthermore, their properties are measured by broad-band optical transmission spectroscopy leading to a very large signal-to-noise ratio even in the multi-megabar pressure regime where ruby measurements become challenging. Finally, their resonant frequencies can be tuned to lie in a convenient part of the visible spectrum accessible to CCD detectors. Theoretical calculations for a nanoshell with a SiO2 core and a golden shell, using both the hybridization model and Mie theory, are presented here. The calculations for the nanoshell in vacuum predict that nanoshells can indeed have a measurable pressure-dependent optical response desirable for gauges. However, when the nanoshells are placed in commonly used DAC pressure media, resonance peak positions as a function of pressure are no longer single valued and depend on the pressure media, rendering them impractical as a pressure gauge. To overcome these problems, an alternative nanoparticle is studied: coating the nanoshell with an extra dielectric layer (SiO2) provides an easy way to shield the pressure gauge from the influence of the medium, leaving the compression of the particle as a result of the pressure as the main effect on the spectrum. We have analyzed the response to pressure up to 200 GPa. We conclude that a coated nanoshell could provide a new gauge for high-pressure measurements that has advantages over current methods.
Effect of K doping on CuPc: C60 heterojunctions
Authors: Cheng Chiu-Ping , Chen Wen-Yen , Wei Ching-Hsuan , Pi Tun-Wen
Published: December 2011

Here, the electronic properties of K-doped copper phthalocyanine (CuPc): C60 heterojunctions are studied via synchrotron-radiation photoemission. The K-doped heterointerfaces were obtained by means of C60 on K1.5CuPc and CuPc on K3C60. The photoelectron spectra show that the potassium prefers to combine with C60. At the C60/K1.5CuPc interface, the K diffuses and transfers negative charge into the C60 overlayer, while no strong chemical reaction could be found at the CuPc/K3C60 interface. A significant shift of the vacuum level was observed in both cases, which was caused by the charge transfer for the C60/K1.5CuPc and by the induced density of interface states (IDIS) dipole for the CuPc/K3C60. The energy level diagrams show that using C60 adsorption on a K-doped CuPc film is good for the improvement of photovoltaic devices. However, the inverse process, that of CuPc on a K-doped C60, is unfavorable for the photovoltaic effect.
Enhanced low-field magnetoresistance in La0.67Sr0.33MnO3:MgO composite films
Authors: Staruch M. , Hires D. , Chen A. , Bi Z. , Wang H. , Jain M.
Published: December 2011

In this paper, we report low-field magnetoresistance observed in preferentially c-axis oriented La0.67Sr0.33MnO3:MgO composite films fabricated on (001) LaAlO3 substrates using a hybrid solution route. Addition of MgO in the composite film results in lowering of Curie temperature (∼300 K) from that of the pure film (∼360 K). The resistivity increases and temperature of highest resistivity of the composite films decrease with the addition of MgO. This behavior is attributed to a small substitution of Mg2+ in the manganite lattice and the presence of MgO near the manganite grain boundaries, thus building tunneling barriers and enhancing the spin polarized tunneling in the composite films. The values of low-field magnetoresistance increase with MgO addition and the composite film with highest amount of MgO exhibits maximum MR of −33% at 0.5 T (5000 Oe) and 10 K.
Copropagating pump and probe experiments on Si-nc in SiO2 rib waveguides doped with Er: The optical role of non-emitting ions
Authors: Navarro-Urrios D. , Ferrarese Lupi F. , Prtljaga N. , Pitanti A. , Jambois O. , Ramírez J. M. , Berencén Y. , Daldosso N. , Garrido B. , Pavesi L.
Published: December 2011

We present a study that demonstrates the limits for achieving net optical gain in an optimized waveguide where Si nanoclusters in SiO2 codoped with Er3+ are the active material. By cross correlating absorption losses measurements with copropagant pump (λpump = 1.48 µm) and probe (λprobe = 1.54 µm) experiments we reveal that the role of more than 80% of the total Er3+ population present on the material (intended for optical amplification purposes) is to absorb the propagating light, since it is unfeasible to invert it.
Characterization of GaSb/GaAs interfacial misfit arrays using x-ray diffraction
Authors: Reyner Charles J. , Wang Jin , Nunna Kalyan , Lin Andrew , Liang Baolai , Goorsky Mark S. , Huffaker D. L.
Published: December 2011

We report a nondestructive, large-area method to characterize dislocation formation at a highly lattice-mismatched interface. The analysis is based on x-ray diffraction and reciprocal space mapping using a standard, lab-based diffractometer. We use this technique to identify and analyze a two-dimensional array of 90° misfit dislocations at a GaSb/GaAs interface. The full width at half maximum of the GaSb 004 reciprocal lattice point is shown to decrease with increasing GaSb epilayer thickness, as expected from theoretical models. Based on these measurements, the variation in the spatial dislocation frequency is calculated to be 1%.
Selective nonlinear response preparation using femtosecond spectrally resolved four-wave-mixing
Authors: Philip Kraack Jan , Motzkus Marcus , Buckup Tiago
Published: December 2011

A novel method is presented to assist the assignment of vibrational coherence in the homodyne degenerate four-wave-mixing technique. The dependence of vibrational coherence dynamics on the interaction sequence of chirped pump and Stokes excitation pulses is exploited to distinguish quantum beating from polarization interference. Moreover, by combining chirped excitation and variable delays between pump and Stokes pulses, it is possible to achieve a controlled excitation of response pathways from a single electronic state and separation of population dynamics and vibrational coherence dynamics within a single response pathway. Numerical simulations are performed in the response function framework, which clearly show that such an approach applies for oscillatory contributions originated in the electronically excited state as well as in the ground state. The approach is experimentally demonstrated in three different polyatomic molecules in solution.
Resonant-tunnelling-diode oscillators operating at frequencies above 1.1 THz
Authors: Feiginov Michael , Sydlo Cezary , Cojocari Oleg , Meissner Peter
Published: December 2011

We present resonant-tunnelling-diode (RTD) oscillators operating at the fundamental frequency of 1111 GHz. We show that our RTDs and RTD oscillators have much room for further improvement of their parameters and for further increase of their operating frequencies. The operating frequencies of several THz should be achievable with RTD oscillators. Our study also shows that operation of RTDs beyond the relaxation-time limit at THz frequencies should be possible. RTD oscillators under study are extremely compact (less than a square millimeter) room-temperature sources of coherent cw THz radiation. Such sources should enable plenty of real-world THz applications.
Irregular spectral position of E || c component of polarized photoluminescence from m-plane InGaN/GaN multiple quantum wells grown on LiAlO2
Authors: Mauder C. , Lutsenko E. V. , Rzheutski M. V. , Reuters B. , Zubialevich V. Z. , Pavlovskii V. N. , Yablonskii G. P. , Heuken M. , Kalisch H. , Vescan A.
Published: December 2011

Polarized temperature dependent photoluminescence (PL) and room temperature (RT) photocurrent spectra of m-plane InGaN/GaN multiple quantum wells grown on LiAlO2 with In content xIn = 5%-30% were studied. As expected, higher xIn leads to larger strain in the wells and enhances both the splitting between the two highest valence subbands and the RT PL degree of polarization. At low temperatures, an irregular red-shift of the PL component with polarization E || c relative to E ⊥ c is observed, which is ascribed to the contribution of recombination of holes localized at band tails within the second highest valence subband.
Origins of dielectric response and conductivity in (Bi1−xNdx)FeO3 multiferroic ceramics
Authors: Tu C.-S. , Yang W.-C. , Schmidt V. H. , Chien R. R.
Published: December 2011

The dielectric response and conductivity have been measured in (Bi1−xNdx)FeO3 (x = 0.0 and 0.05) ceramics as functions of temperature and frequency. A one-dimensional across-barrier model with intrinsic barriers, B (in temperature units), every lattice constant, a, and extrinsic barriers, B + Δ, every distance, d, is introduced to describe the dielectric response and conductivity. The across-barrier hopping is responsible for the high-temperature conductivity and step-like dielectric relaxation in the region of 500–800 K. Good qualitative fits of dielectric dispersion and conductivity are obtained with d = 20–30 nm, B = 8400–8700 K (∼0.72–0.75 eV), and Δ = 2500 K (∼0.215 eV). The resistivity plot of scaled ρ" versus ρ' indicates a contribution of grain boundaries or internal defects to the conductivity.
Vortex motion around a circular cylinder
Authors: Vasconcelos G. L. , Moura M. N. , Schakel A. M. J.
Published: December 2011

The motion of a pair of counter-rotating point vortices placed in a uniform flow around a circular cylinder forms a rich nonlinear system that is often used to model vortex shedding. The phase portrait of the Hamiltonian governing the dynamics of a vortex pair that moves symmetrically with respect to the centerline—a case that can be realized experimentally by placing a splitter plate in the center plane—is presented. The analysis provides new insights and reveals novel dynamical features of the system, such as a nilpotent saddle point at infinity whose homoclinic orbits define the region of nonlinear stability of the so-called Föppl equilibrium. It is pointed out that a vortex pair properly placed downstream can overcome the cylinder and move off to infinity upstream. In addition, the nonlinear dynamics resulting from antisymmetric perturbations of the Föppl equilibrium is studied and its relevance to vortex shedding discussed.
Finite size versus surface effects on magnetic properties of antiferromagnetic particles
Authors: Mandal Suman , Menon Krishnakumar S. R. , Mahatha S. K. , Banerjee S.
Published: December 2011

The observation of finite magnetic moment in antiferromagnetic materials is quite unusual and has been immensely investigated in nanoparticle systems. Here, the structural and magnetic properties of NiO particles are explored by x-ray diffraction, extended x-ray absorption fine structure, and magnetization measurements. Using similar-sized particles with different surface defect structure, we show that the observed magnetic enhancement, which is present even beyond finite-size limit, is due to the surface effects. However, the well known spin glass freezing is found to occur only in nano-regime.
Intra-excitonic relaxation dynamics in ZnO
Authors: Chernikov Alexej , Koch Martin , Laumer Bernhard , Wassner Thomas A. , Eickhoff Martin , Koch Stephan W. , Chatterjee Sangam
Published: December 2011

The temperature and carrier-density dependent excitonic relaxation in bulk ZnO is studied by means of time-resolved photoluminescence. A rate-equation model is used to analyze the population dynamics and the transitions between different exciton states. Intra-excitonic (n = 1) to (n = 2) relaxation is clearly identified at low excitation densities and lattice temperatures with a characteristic time constant of 6 ± 0.5 ps.
Improvement in spontaneous emission rates for InGaN quantum wells on ternary InGaN substrate for light-emitting diodes
Authors: Zhang Jing , Tansu Nelson
Published: December 2011

The spontaneous emission characteristics of green- and red-emitting InGaN quantum wells (QWs) on ternary InGaN substrate are analyzed, and the radiative recombination rates for the QWs grown on ternary substrate were compared with those of InGaN QWs on GaN templates. For green- and red-emitting InGaN QWs on In0.15Ga0.85N substrate, the spontaneous emission rates were found as ∼2.5-3.2 times of the conventional approach. The enhancement in spontaneous emission rate can be achieved by employing higher In-content InGaN ternary substrate, which is also accompanied by a reduction in emission wavelength blue-shift from the carrier screening effect. The use of InGaN substrate is expected to result in the ability for growing InGaN QWs with enhanced spontaneous emission rates, as well as reduced compressive strain, applicable for green- and red-emitting light-emitting diodes.
Dynamics of solidification in Al thin films measured using a nanocalorimeter
Authors: Swaminathan P. , LaVan D. A. , Weihs T. P.
Published: December 2011

We demonstrate how a nanocalorimeter can be used to measure the dynamics of thin film melting and solidification using aluminum as a model system. Recalescence, a rise in temperature due to enthalpy release on solidification, is observed when the rate of heat release is faster than the rate of heat extraction. For thin films, with a large density of nucleation centers at the interface, recalescence effects are observed at high cooling rates where direct measurements of heat capacities and enthalpy changes are challenging. Temperature rates of 104 K/s were applied using nanocalorimeter chips; the nanocalorimeter allows direct measurement of the under cooling, temperature rise during solidification, and the associated changes in enthalpy. This work highlights some of the challenges recalescence causes in physical measurements and provides a numerical strategy to evaluate enthalpy changes during rapid solidification.
Threshold shift observed in resistive switching in metal-oxide-semiconductor transistors and the effect of forming gas anneal
Authors: Liu W. H. , Pey K. L. , Wu X. , Raghavan N. , Padovani A. , Larcher L. , Vandelli L. , Bosman M. , Kauerauf T.
Published: December 2011

The resistive switching mechanism, which is crucial for the operations of resistive random access memory (RRAM) devices, is investigated using HfO2 based MOSFETs. After the SET operation, MOSFETs exhibit a threshold voltage (VT) shift that is found to be closely related to the formation of conductive filaments in the gate oxide. The RESET operation performed through a forming gas anneal treatment is found to have the same effect of applying a reverse polarity gate voltage sweep, as usually done in bipolar switching RRAM devices. After RESET, the gate current and VT measured shift back to their pristine levels, indicating the passivation of oxygen vacancies (forming the conductive path) as the most likely physical mechanism responsible for RRAMs RESET operation. Transmission electron microscopy analysis and physical simulations support these conclusions.
Design of narrow band photonic filter with compact MEMS for tunable resonant wavelength ranging 100 nm
Authors: Liang Guanquan , Lee Chengkuo , Danner Aaron J.
Published: December 2011

A prototype of planar silicon photonic structure is designed and simulated to provide narrow resonant line-width (∼2 nm) in a wide photonic band gap (∼210 nm) with broad tunable resonant wavelength range (∼100 nm) around the optical communication wavelength 1550 nm. This prototype is based on the combination of two modified basic photonic structures, i.e. a split tapered photonic crystal micro-cavity embedded in a photonic wire waveguide, and a slot waveguide with narrowed slabs. This prototype is then further integrated with a MEMS (microelectromechanical systems) based electrostatic comb actuator to achieve “coarse tune” and “fine tune” at the same time for wide range and narrow-band filtering and modulating. It also provides a wide range tunability to achieve the designed resonance even fabrication imperfection occurs.
Influence of living arrangements on health services utilisation in Australia
Authors: Mahmood M. Afzal , Bauze Anna E. , Lokhorst Justin T. , Bi Peng , Saniotis Arthur
Published: December 2011

Background.
The number of people living alone is increasing markedly. Others live as couples only, couples with child(ren) and single adult with child(ren). Health service utilisation could differ for people in different living arrangements as a result of varying levels of risk factors, health status, access to informal care and decision-making for accessing care.

Objective.
To identify the association between living arrangements and health service use.

Methods.
The Australian Bureau of Statistics’ National Health Survey 2001 data for people 18–65 years old were analysed for household composition and service use.

Results.
People in various household types differ in terms of their overall use of health services and their use of services by general practitioners. Sex, rurality, socioeconomic status and status of heart condition significantly influenced the use of health services.

Conclusion.
There are implications for health services provision and planning within the context of rapid changes in living arrangements. Additional research is required to explore the reasons to such differences, level of access to informal care, healthcare decision-making processes and consequences of under- or over-utilisation of services.

What is known about the topic?
Health service use is influenced by the disease burden and pattern, demography, economic factors, access to social support, quality of care and satisfaction with standards of care. These factors may influence access to and use of care.

What does this paper add?
This research points to the potential role of living arrangements on health services use. Many people now live alone and may not have access to informal care, and access to health information and education. People in different living arrangements appear to have different health service use.

What are the implications for practitioners?
Practitioners, in both primary care and acute care sectors, need to consider that patients, including younger people, may not have access to informal care, may present with delays and may not have the needed adequate support during convalescence. Health education needs to consider that people in different living arrangements may be exposed to different levels of risk factors in terms of their healthcare use.
Leg-mounted data-loggers do not affect the reproductive performance of short-tailed shearwaters (Puffinus tenuirostris)
Authors: Carey Mark J.
Published: December 2011

Context
Attaching tracking devices to several avian species could produce negative outcomes. Of particular concern are potential alterations to birds’ reproductive, flight, diving and foraging performances. Attachment of devices may also lead to a bias in results or an inaccurate interpretation of results as birds may not behave ‘normally’.

Aims
The aims of the present study were to evaluate the possible effects of a 5.4-g global location-sensing (GLS) data-logger attached to a modified aluminium band on short-tailed shearwaters (Puffinus tenuirostris (Temminck, 1835)), representing 0.7–1% of adult body mass, breeding on Great Dog Island, Furneaux Group, Tasmania.

Methods
Eighty birds were monitored during two breeding seasons. Twenty-seven GLS data-loggers were attached to birds in 2007, with the remaining birds acting as controls. Breeding success, return rates and body condition were compared between equipped and non-equipped birds.

Key results
In the year of deployment, no evidence of negative effects of attaching data-loggers on hatching success, pre-fledging chick mass or survival was found. However, chicks reared by non-equipped adults were skeletally larger. After controlling for body size, no significant effect on chick body condition was detected between the two groups. In the year of recapture, significantly more GLS-equipped than non-equipped adults returned to the colony. There were no differences in adult body condition, egg size, hatching or fledging success between the two groups. After GLS devices were removed, chick mass and size at pre-fledging were equal between those raised by GLS-equipped and non-equipped adults.

Conclusions
These results suggest that appropriate-sized data-loggers are a relatively benign method of obtaining at-sea foraging and behavioural information from seabirds. However, loggers may be affecting parental care of offspring and this requires further investigation. Importantly, no carry-over effects were observed once the data-loggers were removed after 12 months.

Implications
Identifying any effects of data-logger attachment is imperative for animal welfare but also for the accuracy of tracking data and subsequent interpretation. GLS devices are rapidly becoming smaller and lighter, and if this trend continues, unlock unprecedented opportunities for pelagic seabird research. During long deployments, monitoring individuals and assessing their health and reproductive output should be considered an integral part of all bio-logging studies.
Autoinhibition and phosphorylation-induced activation mechanisms of human cancer and autoimmune disease-related E3 protein Cbl-b
Authors: Kobashigawa Yoshihiro , Tomitaka Akira , Kumeta Hiroyuki , Noda Nobuo N. , Yamaguchi Masaya , Inagaki Fuyuhiko
Published: December 2011

Cbl-b is a RING-type E3 ubiquitin ligase that functions as a negative regulator of T-cell activation and growth factor receptor and nonreceptor-type tyrosine kinase signaling. Cbl-b dysfunction is related to autoimmune diseases and cancers in humans. However, the molecular mechanism regulating its E3 activity is largely unknown. NMR and small-angle X-ray scattering analyses revealed that the unphosphorylated N-terminal region of Cbl-b forms a compact structure by an intramolecular interaction, which masks the interaction surface of the RING domain with an E2 ubiquitin-conjugating enzyme. Phosphorylation of Y363, located in the helix-linker region between the tyrosine kinase binding and the RING domains, disrupts the interdomain interaction to expose the E2 binding surface of the RING domain. Structural analysis revealed that the phosphorylated helix-RING region forms a compact structure in solution. Moreover, the phosphate group of pY363 is located in the vicinity of the interaction surface with UbcH5B to increase affinity by reducing their electrostatic repulsion. Thus, the phosphorylation of Y363 regulates the E3 activity of Cbl-b by two mechanisms: one is to remove the masking of the RING domain from the tyrosine kinase binding domain and the other is to form a surface to enhance binding affinity to E2.
Legionella pneumophila
regulates the small GTPase Rab1 activity by reversible phosphorylcholination
Authors: Tan Yunhao , Arnold Randy J. , Luo Zhao-Qing
Published: December 2011

Effectors delivered into host cells by the
Legionella pneumophila
Dot/Icm type IV transporter are essential for the biogenesis of the specialized vacuole that permits its intracellular growth. The biochemical function of most of these effectors is unknown, making it difficult to assign their roles in the establishment of successful infection. We found that several yeast genes involved in membrane trafficking, including the small GTPase Ypt1, strongly suppress the cytotoxicity of Lpg0695(AnkX), a protein known to interfere severely with host vesicle trafficking when overexpressed. Mass spectrometry analysis of Rab1 purified from a yeast strain inducibly expressing AnkX revealed that this small GTPase is modified posttranslationally at Ser
76
by a phosphorylcholine moiety. Using cytidine diphosphate-choline as the donor for phosphorylcholine, AnkX catalyzes the transfer of phosphorylcholine to Rab1 in a filamentation-induced by cAMP(Fic) domain-dependent manner. Further, we found that the activity of AnkX is regulated by the Dot/Icm substrate Lpg0696(Lem3), which functions as a dephosphorylcholinase to reverse AnkX-mediated modification on Rab1. Phosphorylcholination interfered with Rab1 activity by making it less accessible to the bacterial GTPase activation protein LepB; this interference can be alleviated fully by Lem3. Our results reveal reversible phosphorylcholination as a mechanism for balanced modulation of host cellular processes by a bacterial pathogen.
Normal training response in skeletal muscle of post‐infarction heart failure patients
Authors: Slettaløkken Gunnar , Rehn Tommy A. , Munkvik Morten , Rud Bjarne , Nymark Bernt Sivert , Lunde Per Kristian , Sjaastad Ivar , Sejersted Ole M. , Hallén Jostein
Published: December 2011

Congestive heart failure (CHF) patients experience reduced muscle fatigue resistance and exercise capacity. The aim of this study was to assess whether skeletal muscle in CHF patients has a normal training response compared to healthy subjects. We compared the effect of one‐legged knee extensor (1‐KE) endurance training in CHF patients (n=10), patients with coronary artery disease (CAD, n=9) and healthy subjects (n=13). The training response was evaluated by comparing trained leg and control leg after the training period. The fall in peak torque during 75 maximal 1‐KE isokinetic contractions revealed that CHF patients were less fatigue resistant than healthy subjects in the control leg, but not in the trained leg. Peak power and peak oxygen uptake during dynamic 1‐KE exercise was ~10–16% higher in trained leg than control leg. This training response was not significant different between groups. Muscle biopsies of vastus lateralis showed that fibre type composition was not different between trained leg and control leg. Capillary density was 6.5% higher in trained leg than control leg when all groups were pooled. In conclusion, the more fatigable skeletal muscle of CHF patients responds equally to endurance training compared to skeletal muscle of CAD patients and healthy subjects.
Kinematic characteristics of elite men's 50 km race walking
Authors: Hanley Brian , Bissas Athanassios , Drake Andrew
Published: December 2011

Race walking is an endurance event which also requires great technical ability, particularly with respect to its two distinguishing rules. The 50 km race walk is the longest event in the athletics programme at the Olympic Games. The aims of this observational study were to identify the important kinematic variables in elite men's 50 km race walking, and to measure variation in those variables at different distances. Thirty men were analysed from video data recorded during a World Race Walking Cup competition. Video data were also recorded at four distances during the European Cup Race Walking and 12 men analysed from these data. Two camcorders (50 Hz) recorded at each race for 3D analysis. The results of this study showed that walking speed was associated with both step length (r=0.54,P=0.002) and cadence (r=0.58,P=0.001). While placing the foot further ahead of the body at heel strike was associated with greater step lengths (r=0.45,P=0.013), it was also negatively associated with cadence (r= −0.62,P<0.001). In the World Cup, knee angles ranged between 175 and 186° at initial contact and between 180 and 195° at midstance. During the European Cup, walking speed decreased significantly (F=9.35,P=0.002), mostly due to a decrease in step length between 38.5 and 48.5 km (t=8.59,P=0.014). From this study, it would appear that the key areas a 50 km race walker must develop and coordinate are step length and cadence, although it is also important to ensure legal walking technique is maintained with the onset of fatigue.
Numerical calculation of spin wave dispersions in magnetic nanostructures
Authors: Kumar Dheeraj , Dmytriiev Oleksandr , Ponraj Sabareesan , Barman Anjan
Published: December 2011

We present the numerical calculations of spin wave dispersions in magnetic nanostructures. The dispersion is obtained by processing the space–time data calculated using the finite difference method based micromagnetic simulations. Various issues related to the calculation of the two-dimensional fast Fourier transform and methods to obtain high-quality dispersion curves are discussed. The spatial profile of the spin wave modes is also presented. The method is validated by applying it to various nanomagnetic systems including magnetic nanostripes, magnetic nanowires and confined thin film elements. Further, we calculate the magnonic dispersions in simple 1D and 2D magnonic crystals based on magnetic anti-dot arrays.
The Public Health Specialist and Access to Public Health Advice
Authors: Inglis Nadia Jane , Malhotra Neeraj , Hothersall Ellie , Fowler Tom
Published: December 2011

Public health specialists can be described as leaders of the ‘upstream health workforce’, concerned with preventing unnecessary and ‘revolving door’ contact with health services. Achieving this requires working to promote good health, improve health services and protect populations from infectious disease and environmental risks. Public health work is based upon the recognition that populations are complex constructions of groups of individuals, who may or may not seek help for health problems or be able effectively to take action to improve their own health. This article will define key areas of public health practice giving specific examples of the role of the public health specialist in the UK, as well as how and why primary care professionals might access specialist advice. The examples demonstrate the great potential for improving population health through the complementary efforts of primary care and public health professionals.
The role of nuclear lamin B1 in cell proliferation and senescence
Authors: Shimi Takeshi , Butin-Israeli Veronika , Adam Stephen A. , Hamanaka Robert B. , Goldman Anne E. , Lucas Catherine A. , Shumaker Dale K. , Kosak Steven T. , Chandel Navdeep S. , Goldman Robert D.
Published: December 2011

Nuclear lamin B1 (LB1) is a major structural component of the nucleus that appears to be involved in the regulation of many nuclear functions. The results of this study demonstrate that LB1 expression in WI-38 cells decreases during cellular senescence. Premature senescence induced by oncogenic Ras also decreases LB1 expression through a retinoblastoma protein (pRb)-dependent mechanism. Silencing the expression of LB1 slows cell proliferation and induces premature senescence in WI-38 cells. The effects of LB1 silencing on proliferation require the activation of p53, but not pRb. However, the induction of premature senescence requires both p53 and pRb. The proliferation defects induced by silencing LB1 are accompanied by a p53-dependent reduction in mitochondrial reactive oxygen species (ROS), which can be rescued by growth under hypoxic conditions. In contrast to the effects of LB1 silencing, overexpression of LB1 increases the proliferation rate and delays the onset of senescence of WI-38 cells. This overexpression eventually leads to cell cycle arrest at the G1/S boundary. These results demonstrate the importance of LB1 in regulating the proliferation and senescence of human diploid cells through a ROS signaling pathway.
ArabidopsisDeficient in Cutin FerulateEncodes a Transferase Required for Feruloylation of ω-Hydroxy Fatty Acids in Cutin Polyester
Authors: Rautengarten Carsten , Ebert Berit , Ouellet Mario , Nafisi Majse , Baidoo Edward E.K. , Benke Peter , Stranne Maria , Mukhopadhyay Aindrila , Keasling Jay D. , Sakuragi Yumiko , Scheller Henrik Vibe
Published: December 2011

The cuticle is a complex aliphatic polymeric layer connected to the cell wall and covers surfaces of all aerial plant organs. The cuticle prevents nonstomatal water loss, regulates gas exchange, and acts as a barrier against pathogen infection. The cuticle is synthesized by epidermal cells and predominantly consists of an aliphatic polymer matrix (cutin) and intracuticular and epicuticular waxes. Cutin monomers are primarily C16 and C18 unsubstituted, ω-hydroxy, and α,ω-dicarboxylic fatty acids. Phenolics such as ferulate and p-coumarate esters also contribute to a minor extent to the cutin polymer. Here, we present the characterization of a novel acyl-coenzyme A (CoA)-dependent acyl-transferase that is encoded by a gene designated Deficient in Cutin Ferulate (DCF). The DCF protein is responsible for the feruloylation of ω-hydroxy fatty acids incorporated into the cutin polymer of aerial Arabidopsis (Arabidopsis thaliana) organs. The enzyme specifically transfers hydroxycinnamic acids using ω-hydroxy fatty acids as acyl acceptors and hydroxycinnamoyl-CoAs, preferentially feruloyl-CoA and sinapoyl-CoA, as acyl donors in vitro. Arabidopsis mutant lines carrying DCF loss-of-function alleles are devoid of rosette leaf cutin ferulate and exhibit a 50% reduction in ferulic acid content in stem insoluble residues. DCF is specifically expressed in the epidermis throughout all green Arabidopsis organs. The DCF protein localizes to the cytosol, suggesting that the feruloylation of cutin monomers takes place in the cytoplasm.
Host factors associated with the kinetics of Epstein‐Barr virus DNA load in patients with primary Epstein‐Barr virus infection
Authors: Nakai Hidetaka , Kawamura Yoshiki , Sugata Ken , Sugiyama Hiroko , Enomoto Yoshihiko , Asano Yoshizo , Ihira Masaru , Ohashi Masahiro , Kato Tomochika , Yoshikawa Tetsushi
Published: December 2011

The aims of this study were to elucidate the kinetics of Epstein‐Barr virus (EBV) DNA load in serially collected peripheral blood mononuclear cells of patients with primary EBV infection, and to determine the correlated host factors. Blood samples were collected from 24 patients with primary EBV infection. EBV DNA copy numbers were measured using real‐time polymerase chain reaction. Based on the kinetics of EBV DNA load, the 24 patients were divided into two groups: rapid regression and slow regression. Eighteen of the 24 patients (75%) were included in the slow regression and 6 (25%) in the rapid regression group. No statistically significant differences were observed between the two groups in clinical features and laboratory findings. However, acute phase (3 to 10 days after the onset of the illness) serum samples from six children in the slow regression and four in the rapid regression group revealed significantly higher serum interleukin (IL)‐1β (P= 0.018), IL‐12 (P= 0.009), tumor necrosis factor‐α (P= 0.019), interferon‐inducible protein 10, and monokine induced by interferon γ concentrations in the rapid regression than the slow regression group. On the other hand, sera from six children in the slow regression and four in the rapid regression group in the convalescent phase (14 to 21 days after the onset of the illness) showed no statistically significant differences between the two groups in these biomarker concentrations. Based on this, it was concluded that the kinetics of EBV DNA load can be divided to two different patterns after primary EBV infection, and immune response might be associated with viral clearance.
The impact of antibiotic use on the incidence and resistance pattern of extended‐spectrum beta‐lactamase‐producing bacteria in primary and secondary healthcare settings
Authors: Aldeyab Mamoon A. , Harbarth Stephan , Vernaz Nathalie , Kearney Mary P. , Scott Michael G. , Darwish Elhajji Feras W. , Aldiab Motasem A. , McElnay James C.
Published: December 2011

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• The emergence and spread of bacteria producing extended‐spectrum beta‐lactamases (ESBLs) has important therapeutic and epidemiologic implications.

• A key target for the establishment of hospital antibiotic stewardship is reducing the occurrence of additional antibiotic resistance.

• Further research is needed to accumulate supporting evidence that reducing antibiotic use will result in a parallel reduction in antibiotic resistance.

WHAT THIS STUDY ADDS

• Fluoroquinolone restriction reversed ciprofloxacin resistance in primary and secondary healthcare settings.

• Fluoroquinolone restriction reduced ESBL‐producing bacteria incidence rates in both the primary and secondary healthcare settings.

• This study highlights the value of time‐series analysis in designing efficient antibiotic stewardship.

AIMS

The objective of the present study was to study the relationship between hospital antibiotic use, community antibiotic use and the incidence of extended‐spectrum beta‐lactamase (ESBL)‐producing bacteria in hospitals, while assessing the impact of a fluoroquinolone restriction policy on ESBL‐producing bacteria incidence rates.

METHODS

The study was retrospective and ecological in design. A multivariate autoregressive integrated moving average (ARIMA) model was built to relate antibiotic use to ESB‐producing bacteria incidence rates and resistance patterns over a 5 year period (January 2005–December 2009).

RESULTS

Analysis showed that the hospital incidence of ESBLs had a positive relationship with the use of fluoroquinolones in the hospital (coefficient = 0.174, P= 0.02), amoxicillin‐clavulanic acid in the community (coefficient = 1.03, P= 0.03) and mean co‐morbidity scores for hospitalized patients (coefficient = 2.15, P= 0.03) with various time lags. The fluoroquinolone restriction policy was implemented successfully with the mean use of fluoroquinolones (mainly ciprofloxacin) being reduced from 133 to 17 defined daily doses (DDDs)/1000 bed days (P < 0.001) and from 0.65 to 0.54 DDDs/1000 inhabitants/day (P= 0.0007), in both the hospital and its surrounding community, respectively. This was associated with an improved ciprofloxacin susceptibility in both settings [ciprofloxacin susceptibility being improved from 16% to 28% in the community (P < 0.001)] and with a statistically significant reduction in ESBL‐producing bacteria incidence rates.

DISCUSSION

This study supports the value of restricting the use of certain antimicrobial classes to control ESBL, and demonstrates the feasibility of reversing resistance patterns post successful antibiotic restriction. The study also highlights the potential value of the time‐series analysis in designing efficient antibiotic stewardship.
An Italian retrospective study on the routine clinical use of low‐dose alemtuzumab in relapsed/refractory chronic lymphocytic leukaemia patients
Authors: Cortelezzi Agostino , Gritti Giuseppe , Laurenti Luca , Cuneo Antonio , Ciolli Stefania , Di Renzo Nicola , Musto Pellegrino , Mauro Francesca R. , Cascavilla Nicola , Falchi Lorenzo , Zallio Francesco , Callea Vincenzo , Maura Francesco , Martinelli Sara , Piciocchi Alfonso , Reda Gianluigi , Foà Robin ,   on behalf of the GIMEMA Chronic Lymphoproliferative Disorders Working Party
Published: December 2011

Low‐dose alemtuzumab has shown a favourable toxicity profile coupled with good results in terms of efficacy in relapsed/refractory chronic lymphocytic leukaemia (CLL). We conducted a multicentre retrospective study on the routine clinical use of low‐dose alemtuzumab in this patient setting. One hundred and eight relapsed/refractory CLL patients from 11 Italian centres were included in the analysis. All patients had an Eastern Cooperative Oncology Group performance status ≤2 and the majority (84%) had adenopathies <5cm. Low‐dose alemtuzumab was defined as a total weekly dose ≤45 mg and a cumulative dose ≤600 mg given for up to 18 weeks. The overall response rate was 56% (22% complete remissions). After a median follow‐up of 42·2 months, the median overall survival and progression‐free survival were 39·0 and 19·4 months, respectively. In univariate analysis, response was inversely associated with lymph node (P = 0·01) and spleen (P = 0·02) size, fludarabine‐refractoriness (P = 0·01) and del(11q) (P = 0·009). Advanced age and del(17p) were not associated with a worse outcome. Cumulative dose of alemtuzumab was not associated to response. Toxicities were usually mild and manageable; severe infections occurred in seven patients (7%) during therapy. This retrospective analysis confirms that low‐dose alemtuzumab is a valid and currently used therapeutic option for the treatment of relapsed/refractory CLL.
A new genetic abnormality leading to TP53 gene deletion in chronic lymphocytic leukaemia
Authors: López Cristina , Baumann Tycho , Costa Dolors , López‐Guerra Mónica , Navarro Alba , Gómez Cándida , Arias Amparo , Muñoz Concha , Rozman María , Villamor Neus , Colomer Dolors , Montserrat Emili , Campo Elías , Carrió Ana
Published: December 2011

The analysis of chromosomal abnormalities provides significant prognostic information in patients with chronic lymphocytic leukaemia (CLL), a disease with a highly heterogeneous clinical course. Chromosomal abnormalities commonly found are trisomy 12, del(13)(q14), del(11)(q22‐23), del(17)(p13) and del(6)(q21). Translocations are present in some patients and affect regions recurrently involved in CLL. This report describes the clinical and pathological characteristics of four CLL patients showing a new recurrent chromosomal abnormality dic(8;17)(p11;p11), that implied loss of the TP53 gene in all cases. In addition, TP53 gene was mutated in three out of four patients. Mechanically, Low Copy Repeats (LCR) in 17p12 and 8p11 may explain the origin of the translocation by non‐allelic homologous recombination (NAHR). Isolated dic(8;17)(p11;p11) in patients with mutated IGHV genes status may not have the same prognostic impact as other mutations or deletions affecting the TP53 gene. Larger series are needed to better evaluate the clinical impact of this chromosomal aberration during the course of the disease.