bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of epitaxial Co1−xNixSi2 nanowires on thin-oxide-capped (001)Si
Authors: Li Wun-Shan , Lee Chung-Yang , Liu Chun-Yi , Chu Yen-Chang , Chen Sheng-Yu , Chen Lih-Juann
Published: February 2013

Epitaxial Co1−xNixSi2 alloy nanowires have been grown on (001)Si substrates by a combination of reactive deposition epitaxy and oxide-mediated epitaxy. The thin native oxide layer can serve as a diffusion barrier to diminish the flux of metal atoms from the top of oxide layer to Si surface and promote the growth of nanowires. The elemental distributions of Ni and Co in nanowires were determined by energy dispersive spectroscopy in a transmission electron microscope. The factors that cause the distributions of Ni and Co in nanowires were discussed.
A simple-versatile approach to achieve all-Si-based optical micro-cavities
Authors: Gallo I. B. , Zanatta A. R.
Published: February 2013

At present, solid thin films are recognized by their well established and mature processing technology that is able to produce components which, depending on their main characteristics, can perform either passive or active functions. Additionally, Si-based materials in the form of thin films perfectly match the concept of miniaturized and low-consumption devices—as required in various modern technological applications. Part of these aspects was considered in the present work that was concerned with the study of optical micro-cavities entirely based on silicon and silicon nitride thin films. The structures were prepared by the sputtering deposition method which, due to the adopted conditions (atmosphere and deposition rate) and arrangement of layers, provided cavities operating either in the visible (at ∼670 nm) or in the near-infrared (at ∼1560 nm) wavelength ranges. The main differential of the work relies on the construction of optical micro-cavities with a reduced number of periods whose main properties can be changed by thermal annealing treatments. The work also discusses the angle-dependent behavior of the optical transmission profiles as well as the use of the comsol software package to simulate the micro-cavities.
Room temperature magnetoelectric effects in bulk poly-crystalline materials of M- and Z-type hexaferrites
Authors: Ebnabbasi Khabat , Mohebbi Marjan , Vittoria Carmine
Published: February 2013

The converse magnetoelectric effect in poly-crystalline Z-type, Sr3Co2Fe24O41, and M-type, SrCo2Ti2Fe8O19 (SCTFO), hexaferrite materials are reported. The change in remanent magnetization (Mr) for M-SCTFO sintered in oxygen and sintered in air is similar and approximately equals to ∼3% in 13 kV/cm electric field and for Z-type is ∼12% in ∼10 kV/cm electric field. The measured magnetoelectric coupling coefficient, α, values at room temperature for Z-type and M-type hexaferrites sintered in O2 were measured to be 7.6 × 10−10  sm−1 and 2.4 × 10−10  sm−1, respectively. Sintering the M-type in air reduced to 1.7 × 10−10  sm−1. As it is well known, lack of oxygen in local oxygen sites implies lower resistivity and a modified magnetic structures or state. However, in magnetoelectric hexaferrites, there is an additional effect due to lack of oxygen, and the spin spiral configuration is significantly modified to lower the induced magnetization upon the application of a DC voltage or electric field.
Electrical properties of undoped GaN films grown by maskless epitaxial lateral overgrowth
Authors: Polyakov A. Y. , Jeon Dae-Woo , Lee In-Hwan , Smirnov N. B. , Govorkov A. V. , Kozhukhova E. A. , Yakimov E. B.
Published: February 2013

Electrical properties, deep traps spectra, microcathodoluminescence (MCL) spectra measurements, MCL imaging, and electron beam induced current (EBIC) imaging were performed for undoped GaN films grown by metalorganic chemical vapor deposition using maskless epitaxial lateral overgrowth on basal plane sapphire. The films showed a low dislocation density of ∼108 cm−2 in the laterally overgrown wings and an order of magnitude higher dislocation density in vertical growth seed regions, as determined by MCL and EBIC imaging. The polarity of EBIC signal measurements and the room temperature capacitance-voltage characteristics suggested that the high-dislocation-density seed regions were high-resistivity p-type, with the Fermi level pinned near Ev + 0.4 eV, as determined by admittance spectroscopy. The wing regions were n-type, with low residual donor concentration of some 1014 cm−3 near the surface. The donor concentration further decreased upon movement towards the sapphire substrate. Some possible explanations of the observed effects are discussed.
Electro-degradation and resistive switching of Fe-doped SrTiO3 single crystal
Authors: Wojtyniak M. , Szot K. , Wrzalik R. , Rodenbücher C. , Roth G. , Waser R.
Published: February 2013

In this work, the results of the electrocoloration of strontium titanate single crystals with different iron concentrations are presented. The samples of SrTiO3(100) doped with 0.06 at. % and 0.13 at. % of iron were electroreduced at low pressure (10−8 mbar) and elevated temperature (250 °C) using a DC voltage of 200 V. This led to the migration of oxygen vacancies and subsequent electrocoloration of the samples, which was confirmed by optical analysis and electrical measurements. Evolution of the color front was compared with finite element calculations of electric potential indicating good agreement. Both macroscopic and nanoscopic measurements showed insulator-metal transition at several hundreds of seconds (0.06%Fe) and resistive switching behavior. We found that the resistive switching is clearly modified by the oxygen partial pressure of the ambient atmosphere. Moreover, after electroreduction, in the region between the electrodes, stripes can be found following simple crystallographic directions connected with the extended defects and easy diffusion paths also observed in the single crystals of undoped strontium titanate. Furthermore, migration of negatively charged oxygen ions towards the anode led to the formation of oxygen bubbles trapped between the surface of the crystal and the electrode. Using atomic force microscopy, we were able to measure the geometry of a bubble and calculate the oxygen pressure necessary for the formation of such bubbles and the total amount of oxygen ions trapped within.
Shuffle-glide dislocation transformation in Si
Authors: Li Z. , Picu R. C.
Published: February 2013

The transformation of dislocation cores from the shuffle to the glide set of {111} glide planes in Si is examined in this work. The transformation is thermally activated and is favored by a resolved shear stress which applies no force on the original perfect shuffle dislocation. A resolved shear stress driving dislocation motion in the glide plane is not observed to promote the transition. The stress-dependent activation energy for the described shuffle-glide transformation mechanism is evaluated using a statistical analysis. It is observed that the transformation is not associated with an intermediate metastable state, as has been previously suggested in the literature.
Upconversion luminescence in Er3+ doped Ga10Ge25S65 glass and glass-ceramic excited in the near-infrared
Authors: Lozano B. Whualkuer , de Araújo Cid B. , Ledemi Yannick , Messaddeq Younes
Published: February 2013

The infrared-to-visible frequency upconversion was investigated in Er3+-doped Ga10Ge25S65 glass and in the transparent glass-ceramic obtained by heat-treatment of the glass above its glass-transition temperature. Continuous-wave and pulsed lasers operating at 980 nm and 1480 nm were used as excitation sources. The green (2H11/2 → 4I15/2; 4S3/2 → 4I15/2) and red (4F9/2 → 4I15/2) photoluminescence (PL) signals due to the Er3+ ions were characterized. The PL decay times were influenced by energy transfer among Er3+ ions, by cross-relaxation processes and by energy transfer from the Er3+ ions to the host material. The PL from the Er3+ ions hosted in the crystalline phase was distinguished only when the glass-ceramic was excited by the 1480 nm pulsed laser. The excitation pathways responsible for the green and red PL bands are discussed to explain the differences between the spectra observed under continuous-wave and pulsed excitation.
Non-volatile, reversible switching of the magnetic moment in Mn-doped ZnO films
Authors: Wang X. L. , Shao Q. , Leung C. W. , Ruotolo A.
Published: February 2013

We report on the observation of a non-volatile, reversible switching of the magnetic moment in Mn-doped ZnO thin films. The system is a typical oxide memristor based on an oxygen-deficient semiconductor oxide. In the present study, the oxide semiconductor is ferromagnetic at room temperature. We found that the bistable switching of the resistive state was accompanied by a bistable switching of the magnetic moment at room temperature. Our results support the hypothesis that ferromagnetism in Mn-doped ZnO is mediated by oxygen-vacancies.
Domain wall mobility in rapidly solidified ultrathin amorphous wires
Authors: Óvári T.-A. , Chiriac H.
Published: February 2013

Results on the complex relation between magnetic domain wall mobility and magnetic anisotropy in rapidly solidified amorphous submicron wires and nanowires are reported. A distinctly nonlinear dependence of the domain wall mobility on wire diameter has been found in the case of positive magnetostrictive wires, whilst the same dependence is monotonic in the case of nearly zero magnetostrictive ones. This significant difference has been proven to originate in the different types of magnetic anisotropy, which exist in thin amorphous wires having different signs and magnitudes of the magnetostriction.
Strain-engineered A-type antiferromagnetic order in YTiO3: A first-principles calculation
Authors: Huang Xin , Tang Yankun , Dong Shuai
Published: February 2013

The epitaxial strain effects on the magnetic ground state of YTiO3 films grown on LaAlO3 substrates have been studied using the first-principles density-functional theory. With the in-plane compressive strain induced by LaAlO3 (001) substrate, A-type antiferromagnetic order emerges against the original ferromagnetic order. This phase transition from ferromagnet to A-type antiferromagnet in YTiO3 film is robust since the energy gain is about 7.64 meV per formula unit despite the Hubbard interaction and modest lattice changes, even though the A-type antiferromagnetic order does not exist in any RTiO3 bulks.
The influence of laser-induced nanosecond rise-time stress waves on the microstructure and surface chemical activity of single crystal Cu nanopillars
Authors: Youssef G. , Crum R. , Prikhodko S. V. , Seif D. , Po G. , Ghoniem N. , Kodambaka S. , Gupta V.
Published: February 2013

An apparatus and test procedure for fabrication and loading of single crystal metal nanopillars under extremely high pressures (>1 GPa) and strain rates (>107 s−1), using laser-generated stress waves, are presented. Single-crystalline Cu pillars (∼1.20 μm in tall and ∼0.45 μm in diameter) prepared via focused ion beam milling of Cu(001) substrates are shock-loaded using this approach with the dilatational stress waves propagating along the [001] axis of the pillars. Transmission electron microscopy observations of shock-loaded pillars show that dislocation density decreases and that their orientation changes with increasing stress wave amplitude, indicative of dislocation motion. The shock-loaded pillars exhibit enhanced chemical reactivity when submerged in oil and isopropyl alcohol solutions, due likely to the exposure of clean surfaces via surface spallation and formation of surface steps and nanoscale facets through dislocation motion to the surface of the pillars, resulting in growth of thin oxide films on the surfaces of the pillars.
Demonstration and characterization of an ambipolar high mobility transistor in an undoped GaAs/AlGaAs quantum well
Authors: Croxall A. F. , Zheng B. , Sfigakis F. , Das Gupta K. , Farrer I. , Nicoll C. A. , Beere H. E. , Ritchie D. A.
Published: February 2013

We report an ambipolar device fabricated in undoped GaAs/AlGaAs quantum wells (widths 10 and 25 nm) with front and backgates that allow almost two orders of magnitude in density to be accessed in the same device (7×109cm−2 to 5×1011cm−2). By changing the well width, the relative electron and hole mobilities can be tuned, approaching similar velocities. We describe an approach to fully characterize the quantum well, including the impurity backgrounds and both the upper and lower interfaces, making use of the ability to control the carrier density and the position of the wavefunction independently over a wide range.
Modeling of colossal magnetoresistance in La0.67Ca0.33MnO3/Pr0.67Ca0.33MnO3 superlattices: Comparison with individual (La1−yPry)0.67Ca0.33MnO3 films
Authors: Hühn S. , Jungbauer M. , Michelmann M. , Massel F. , Koeth F. , Ballani C. , Moshnyaga V.
Published: February 2013

Colossal magnetoresistance (CMR) and nm-scale electronic inhomogeneity close to the first order phase transition in perovskite manganites, e.g., (La1−yPry)0.67Ca0.33MnO3 still remain a puzzling phenomenon. We experimentally model a metal-insulator phase coexistence by growing a short period (LCMOn/PCMOn)m superlattices (SLs) with the same thickness for both components. CMR effect was studied as a function of the individual layer thickness n = 2–8 and then compared with chemically homogeneous (La1−yPry)0.67Ca0.33MnO3 LPCMO films. We show that SLs can be superimposed in the phase diagram of LPCMO. The results also point out the importance of the nm-scale electronic rather than chemical separation for realization of the CMR effect as well as limits the lowest boundary for the thickness of an individual manganite material to n∼4u.c.
Reduction of the efficiency droop in silicon nitride light-emitting devices by localized surface plasmons
Authors: Wang Feng , Li Dongsheng , Jin Lu , Yang Deren , Que Duanlin
Published: February 2013

The external quantum efficiency as well as its degeneration in silicon nitride light-emitting devices is significantly improved by the addition of metal nanostructures. The origin of this efficiency droop phenomenon is investigated in detail via the analysis of the dominant process contributing to the light output power and the carrier injection conditions for the devices with and without metal nanostructures. We attribute this droop mainly to the nonradiative Auger recombination as the introduction of metal nanostructures would suppress the Auger process but make the carrier overflow more serious due to the enhanced local electrical field by localized surface plasmon resonance.
Controlled growth of vertical ZnO nanowires on copper substrate
Authors: Ngo-Duc Tam-Triet , Gacusan Jovi , Kobayashi Nobuhiko P. , Sanghadasa Mohan , Meyyappan M. , Oye Michael M.
Published: February 2013

We present an approach for diameter control of vertically aligned ZnO nanowires (NWs) grown directly on copper substrates. Vapor-solid growth was done at 550 °C with solid Zn precursor under Ar/O2 flow, and the resulting nanowires with in situ-controllable diameters ranged between 50 to 500 nm. The nanowires were observed to elongate in tip growth and diameters were directly controlled by varying the oxygen concentration. Direct growth of vertical wires on metal substrates is expected to be useful to construct piezoelectric devices and applications involving sensors and detectors.
Electron spin resonance in CeB6
Authors: Schlottmann P.
Published: February 2013

CeB6 is a cubic heavy fermion compound with antiferro-quadrupolar (AFQ) order below 4 K. The effects of the interplay of AFQ and ferromagnetic correlations on the phase diagram and the electron spin resonance linewidth are discussed. An itinerant picture within the AFQ phase is necessary to explain the electron spin resonances for CeB6.
Interference and memory capacity effects in memristive systems
Authors: Hermiz John , Chang Ting , Du Chao , Lu Wei
Published: February 2013

Short-term memory implies the existence of a capacity limit beyond which memory cannot be securely formed and retained. The underlying mechanisms are believed to be two primary factors: decay and interference. Here, we demonstrate through both simulation and experiment that the memory capacity effect can be implemented in a parallel memristor circuit, where decay and interference are achieved by the inherent ion diffusion in the device and the competition for current supply in the circuit, respectively. This study suggests it is possible to emulate high-level biological behaviors with memristor circuits and will stimulate continued studies on memristor-based neuromorphic circuits.
Highly efficient inverted polymer solar cells with a solution-processable dendrimer as the electron-collection interlayer
Authors: Murugesan Vajjiravel , Sun Kuan , Ouyang Jianyong
Published: February 2013

Poly(amido amine) (PAMAM, generation 2), a solution-processable dendrimer, is used as the electron-collection interlayer on indium tin oxide (ITO) for inverted polymer solar cells (PSCs) with poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester as the active materials. The inverted PSCs exhibited a power conversion efficiency of 3.53% under AM1.5G illumination, which is significantly higher than that of the control inverted PSCs with blank ITO and comparable to that of the control PSCs with normal architecture. The high-performance of the inverted PSCs is attributed to the reduction of the work function of ITO by 0.75 eV by PAMAM.
Enhanced light extraction from InGaN/GaN quantum wells with silver gratings
Authors: Homeyer E. , Mattila P. , Oksanen J. , Sadi T. , Nykänen H. , Suihkonen S. , Symonds C. , Tulkki J. , Tuomisto F. , Sopanen M. , Bellessa J.
Published: February 2013

We demonstrate that an extraction enhancement by a factor of 2.8 can be obtained for a GaN quantum well structure using metallic nanostructures, compared to a flat semiconductor. The InGaN/GaN quantum well is inserted into a dielectric waveguide, naturally formed in the structure, and a silver grating is deposited on the surface and covered with a polymer film. The polymer layer greatly improves the extraction compared to a single metallic grating. The comparison of the experiments with simulations gives strong indications on the key role of weakly guided modes in the polymer layer diffracted by the grating.
Dopant selection rules for desired electronic structure and vacancy formation characteristics of TiO2 resistive memory
Authors: Zhao Liang , Park Seong-Geon , Magyari-Köpe Blanka , Nishi Yoshio
Published: February 2013

Doping has often been considered for performance improvement of resistive memories (ReRAM), but the effects of many different dopants have not been distinguished. To obtain a systematic understanding of doping effects, density functional theory calculations are performed to investigate 9 metal dopants in TiO2 ReRAM. The dopants' effects on both electronic structures and vacancy-formation stability of single vacancy and conductive filament structures are discussed in detail. Trends in the physical properties using various dopants are revealed and well explained by valence-electron-based rules. Their implications to resistive switching suggest that forming/switching characteristics can be adjusted continuously by valence-based dopant selection.
Primary health care practitioner perspectives on the management of insomnia: a pilot study
Authors: Cheung Janet M. Y. , Atternäs Kristina , Melchior Madeleine , Marshall Nathaniel S. , Fois Romano A. , Saini Bandana
Published: February 2013

This paper reports a qualitative pilot study exploring primary care health practitioners’ perspectives on the management of insomnia following the extensive media coverage on the adverse effects of zolpidem in 2007–08. General practitioners and community pharmacists were recruited throughout metropolitan Sydney, New South Wales using a convenience sampling and snowballing technique. Demographic information was collected from each participant followed by a semistructured interview. In total 22 participants were interviewed, including eight general practitioners and 14 community pharmacists. Interview transcripts were analysed using ‘framework analysis’. Participants’ responses illuminated some of the key issues facing primary care practitioners in the management of insomnia. Practitioners perceived there to be an overreliance on pharmacotherapy among insomnia patients and inadequate support for directing patients to alternative treatment pathways if they require or prefer non-pharmacological management. Current prescribing trends appear to favour older benzodiazepines in new cases of insomnia whereas some successful sporadic users of zolpidem have continued to use zolpidem after the media coverage in 2007–08. The findings of this pilot study suggest the need to address the limitations in the management of insomnia within the current health care system, to revise and disseminate updated insomnia guidelines and to provide educational opportunities and resources to primary care practitioners concerning management options.
Runoff and sediment yield under simulated rainfall on hillslopes in the Loess Plateau of China
Authors: Zhao Xining , Wu Pute , Chen Xiaoli , Helmers Matthew J. , Zhou Xiaobo
Published: February 2013

Runoff volume, sediment yield and infiltration on hillslope in the hilly region of Loess Plateau were studied using a rainfall simulator. Two land cover (natural grassland, NG, and bare hillslope, BS) and three different rainfall intensities (2.0, 1.5, 0.75 mm min–1) were implemented. The runoff time of the NG2.0 treatment was 4.8 min earlier, the average infiltration rate was 5.60% lower, the runoff rate was 1.12 times higher and the sediment production rate was 3.28 times lower than those in the BS2.0 treatment. The runoff time for the NG1.5 and the NG0.75 treatments were 6 and 27 min slower, respectively, the average infiltration rate were 10.78 and 23.52% higher, respectively, the runoff rate were 1.67 and 4.25 times lower, respectively, and the sediment production rate were 5.21 and 16.75 times lower, respectively, than those for the BS1.5 and BS0.75 treatments. The effects of slope on sediment reduction were significantly greater than the effects of its runoff reduction, and there occurred more significant sediment-reducing effects with the decrease of rainfall intensity. Efficient use of rainfall runoff in the natural grassland at high intensity should be taken into considerations especially under current conditions of the co-existing drought-caused water shortage and soil erosion in the loess hilly regions.
Remembering the repression of the Stalin era in Russia: on the non-transmission of family memory
Authors: Duprat-Kushtanina Veronika
Published: February 2013

Research into some 30 families has revealed blank spaces in the history of many of these families, most of which date from the Stalin period. My thesis is that the internal policy of the Soviet state, with its repression and stigmatization of victims and their families, contributed to making certain pages of Soviet history disappear from family memories, or be reinterpreted within these memories. The policies of physical and symbolic stratification of the new “communist” society and stigmatization of broad social groups tended to create a gap between the social outcasts and their families. Families were impelled to “purge” their past and to eliminate the elements that could make them discreditable: to change names, surnames, and fathers’ names, to destroy the documents and photographs containing information about repressed people and to forget relatives lost from sight in the political turmoil. With the disappearance of eyewitnesses, firsthand memories that had not been transmitted to subsequent generations fell out of family history. These memory omissions result in these pages of family history being entirely wiped out, or lead to fragmented and impersonal memories.
Evidence for galaxies being pre-processed before accreted into clusters
Authors: Mahajan Smriti
Published: February 2013

I use the spectroscopic data for galaxies in and around 28 nearby (0.02 ≤ z ≤ 0.06) X-ray bright galaxy clusters, to show that the incidence of k+A (or post-starburst) galaxies (EW(Hα) < 2 Å in emission and EW(Hδ) > 3 Å in absorption) may be correlated with the accretion of small galaxy groups in clusters. At r < 2r200, the k+A galaxies are found in regions of higher galaxy density relative to other cluster galaxies. The k+A galaxies have a positively skewed distribution of absolute velocity, |vlos|/σv, where vlos is the difference between the line-of-sight velocity of the galaxy and the cluster's mean, and σv is the cluster's velocity dispersion. This distribution is statistically different from that of other cluster galaxies within 2r200, and in the same absolute velocity range. Moreover, 87 per cent of clusters in the sample studied here show statistically significant substructure in their velocity distribution, and 91.4 per cent of all the k+A galaxies are found to be a part of one of these substructures with 4–10 members. These results suggest that star formation in these k+A galaxies is likely to have been quenched due to ‘pre-processing’ in a poor group-like environment before they are accreted into clusters. I also find a mild, but statistically significant trend in the fraction of k+A galaxies increasing with the temperature of the X-ray emitting gas in clusters.
Pedometer-driven Walking for Chronic Low Back Pain
Authors: McDonough Suzanne M. , Tully Mark A. , Boyd Adele , O’Connor Seán R. , Kerr Daniel P. , O’Neill Siobhán M. , Delitto Antony , Bradbury Ian , Tudor-Locke Catrine , Baxter George David , Hurley Deirdre A.
Published: February 2013

Objectives:

To evaluate the feasibility of an RCT of a pedometer-driven walking program and education/advice to remain active compared with education/advice only for treatment of chronic low back pain (CLBP).

Methods:

Fifty-seven participants with CLBP recruited from primary care were randomly allocated to either: (1) education/advice (E, n=17) or (2) education/advice plus an 8-week pedometer-driven walking program (EWP, n=40). Step targets, actual daily step counts, and adverse events were recorded in a walking diary over the 8 weeks of intervention for the EWP group only. All other outcomes (eg, functional disability using the Oswestry Disability Questionnaire (ODQ), pain scores, physical activity (PA) measurement etc.) were recorded at baseline, week 9 (immediately post-intervention), and 6 months in both groups.

Results:

The recruitment rate was 22% and the dropout rate was lower than anticipated (13% to 18% at 6 mo). Adherence with the EWP was high, 93% (n=37/40) walked for ≥6 weeks, and increased their steps/day (mean absolute increase in steps/d, 2776, 95% confidence interval [CI], 1996-3557) by 59% (95% CI, 40.73%-76.25%) from baseline. Mean percentage adherence with weekly step targets was 70% (95% CI, 62%-77%). Eight (20%) minor-related adverse events were observed in 13% (5/40) of the participants. The EWP group participants demonstrated an 8.2% point improvement (95% CI, −13 to −3.4) on the ODQ at 6 months compared with 1.6% points (95% CI, –9.3 to 6.1) for the E group (between group d=0.44). There was also a larger mean improvement in pain (d=0.4) and a larger increase in PA (d=0.59) at 6 months in EWP.

Discussion:

This preliminary study demonstrated that a main RCT is feasible. EWP was safe and produced a real increase in walking; CLBP function and pain improved, and participants perceived a greater improvement in their PA levels. These improvements require confirmation in a fully powered RCT.
Long-term Results of Percutaneous Lumbar Decompression for LSS
Authors: Chopko Bohdan W.
Published: February 2013

Objective:

The aim of this report was to evaluate the long-term effectiveness and safety of mild lumbar decompression for the treatment of neurogenic claudication associated with lumbar spinal stenosis. This technique uses a percutaneous dorsal approach to remove small portions of ligament and lamina, thereby restoring space and decompressing the spinal canal.

Materials and Methods:

Two-year data are reported for 45 patients treated with mild decompression at 11 US sites. Outcome measures included the Visual Analog Scale (VAS), Oswestry Disability Index, and Zurich Claudication Questionnaire. Safety was monitored throughout the procedural and follow-up period for all patients. Interim data are included for these patients at 1 week, 6 months, and 1-year follow-up.

Results:

Seventy-one percent of patients reported improvement in VAS at the end of the reporting period. At 2 years, patients demonstrated a statistically significant reduction of pain as measured by VAS, and improvement in physical function and mobility was significant as measured by Zurich Claudication Questionnaire and Oswestry Disability Index. Tukey honestly significant different test found significant improvement in all outcome measures from baseline to each follow-up interval. Further, major improvement occurred by 1-week follow-up and showed no difference between each subsequent follow-up, signifying considerable stability and durability of the initial result over time. No major device or intraprocedural adverse events were reported.

Discussion:

In this report of 2-year follow-up on 45 patients treated with mild percutaneous lumbar decompression, patients experienced statistically significant pain relief and improved functionality.
EMBOLUS-INDUCED BRANCH RETINAL ARTERY OCCLUSION WITH A PRESENTING BEST-CORRECTED VISUAL ACUITY OF <6/12 AND VISUAL FIELD DEFECT
Authors: Hsu Tsui-Kang , Chen Shih-Jen , Lei Jianqin , Wu Zhifeng , Lin Chih-Ching , Chen Mi-Mi , Lin Tai-Chi , Liu Jorn-Hon , Chao Hsiao-Ming
Published: February 2013

Purpose:

To study the effects of translumenal Nd:YAG embolectomy (TYE) on the visual functions of patients presenting with decreased vision (<6/12) and visual field defect (VFD) from embolus-induced branch retinal artery occlusions.

Methods:

Case reports.

Results:

The initial information available for five Chinese patients consisted of best-corrected visual acuity, visual field, and the branch retinal artery embolus location/laterality. These consisted of Case 1 (6/15; 3-day upper VFD; temporal lower first bifurcation; left eye), Case 2 (6/120; 1-week upper VFD; macular edema; disk; right eye), Case 3 (6/30; 1-week upper VFD; temporal lower first bifurcation; left eye), Case 4 (6/60; 1-day lower VFD; temporal upper first bifurcation; left eye), and Case 5 (counting finger; temporal upper first bifurcation; left eye). In all five cases, a fluorescein angiogram showed delayed arteriolar filling. At approximately 2 weeks after a single TYE treatment (Cases 1, 3, and 5) or a double TYE treatment (Case 4), fluorescein angiogram showed restoration of arteriolar perfusion. Furthermore, the patients' visual field and MP-1 sensitivity reductions were attenuated in Cases 1, 3 and 4, and their best-corrected visual acuities had improved to 6/10 (Case 1), 6/7.5 (Case 3), 6/6 (Case 4), and 6/60 (Case 5). In Case 2, 2 TYE treatments combined with Avastin and Kenacort also improved her situation despite persistent macular edema with the best-corrected visual acuity further increasing to 6/7.5.

Conclusion:

Conclusively, TYE is a safe and effective procedure that can be used to treat eyes with embolus-induced branch retinal artery occlusion with a presenting best-corrected visual acuity of <6/12 and visual defect.
A trade-off between having many sons and shorter maternal post-reproductive survival in pre-industrial Finland
Authors: Helle Samuli , Lummaa Virpi
Published: February 2013

A bias in reproduction towards sons, which are energetically more costly than daughters, has been suggested to shorten parental lifespan, but previous results have been mixed. Reproductive costs should be most evident in low rather than high resource settings, and are not expected to be severe in men, because women pay higher direct costs of reproduction. We, therefore, used demographic data from pre-industrial Finland to investigate whether the number of sons and daughters born affected their parents’ post-reproductive survival and whether this was related to parent's resource availability. Irrespective of access to resources, mothers, but not fathers, with many sons suffered from reduced post-reproductive survival, and this association decreased as mothers aged. Our results provide evidence that Finnish mothers traded long post-reproductive lifespan for giving birth to many sons.
Absence of major histocompatibility complex class II mediated immunity in pipefish,
Syngnathus typhle
: evidence from deep transcriptome sequencing
Authors: Haase David , Roth Olivia , Kalbe Martin , Schmiedeskamp Gisela , Scharsack Jörn P. , Rosenstiel Philip , Reusch Thorsten B. H.
Published: February 2013

The major histocompatibility complex (MHC)-mediated adaptive immune system is the hallmark of gnathostome immune defence. Recent work suggests that cod-like fishes (Gadidae) lack important components of the MHC class II mediated immunity. Here, we report a putative independent loss of functionality of this pathway in another species, the pipefish
Syngnathus typhle
, that belongs to a distantly related fish family (Syngnathidae). In a deep transcriptome sequencing approach comprising several independent normalized and non-normalized expressed sequence tag (EST) libraries with approximately 7.5 × 10
8
reads, sequenced with two next generation platforms (454 and Illumina), we were unable to identify MHC class IIα/β genes as well as genes encoding associated receptors. Along with the recent findings in cod, our results suggest that immune systems of the Euteleosts may be more variable than previously assumed.
The role of the nucleosome acidic patch in modulating higher order chromatin structure
Authors: Kalashnikova Anna A. , Porter-Goff Mary E. , Muthurajan Uma M. , Luger Karolin , Hansen Jeffrey C.
Published: February 2013

Higher order folding of chromatin fibre is mediated by interactions of the histone H4 N-terminal tail domains with neighbouring nucleosomes. Mechanistically, the H4 tails of one nucleosome bind to the acidic patch region on the surface of adjacent nucleosomes, causing fibre compaction. The functionality of the chromatin fibre can be modified by proteins that interact with the nucleosome. The co-structures of five different proteins with the nucleosome (LANA, IL-33, RCC1, Sir3 and HMGN2) recently have been examined by experimental and computational studies. Interestingly, each of these proteins displays steric, ionic and hydrogen bond complementarity with the acidic patch, and therefore will compete with each other for binding to the nucleosome. We first review the molecular details of each interface, focusing on the key non-covalent interactions that stabilize the protein–acidic patch interactions. We then propose a model in which binding of proteins to the nucleosome disrupts interaction of the H4 tail domains with the acidic patch, preventing the intrinsic chromatin folding pathway and leading to assembly of alternative higher order chromatin structures with unique biological functions.
The strategy of psychopathy: primary psychopathic traits predict defection on low-value relationships
Authors: Gervais Matthew M. , Kline Michelle , Ludmer Mara , George Rachel , Manson Joseph H.
Published: February 2013

Recent evidence suggests that psychopathy is a trait continuum. This has unappreciated implications for understanding the selective advantage of psychopathic traits. Although clinical psychopathy is typically construed as a strategy of unconditional defection, subclinical psychopathy may promote strategic conditional defection, broadening the adaptive niche of psychopathy within human societies. To test this, we focus on a ubiquitous real-life source of conditional behaviour: theexpected relational valueof social partners, both in terms of their quality and the likely quantity of future interactions with them. We allow for conversational interaction among participants prior to their playing an unannounced, one-shot prisoner's dilemma game, which fosters naturalistic interpersonal evaluation and conditional behaviour, while controlling punishment and reputation effects. Individuals scoring higher on factor 1 (callous affect,interpersonal manipulation) of the Levenson self-report psychopathy scale defected conditionally on two kinds of low-value partners: those who interrupted them more during the conversation, and those with whom they failed to discover cues to future interaction. Both interaction effects support the hypothesis that subclinical primary psychopathy potentiates defection on those with low expected relational value. These data clarify the function and form of psychopathic traits, while highlighting adaptive variation in human social strategies.
Meandering worms: mechanics of undulatory burrowing in muds
Authors: Dorgan Kelly M. , Law Chris J. , Rouse Greg W.
Published: February 2013

Recent work has shown that muddy sediments are elastic solids through which animals extend burrows by fracture, whereas non-cohesive granular sands fluidize around some burrowers. These different mechanical responses are reflected in the morphologies and behaviours of their respective inhabitants. However,Armandia brevis, a mud-burrowing opheliid polychaete, lacks an expansible anterior consistent with fracturing mud, and instead uses undulatory movements similar to those of sandfish lizards that fluidize desert sands. Here, we show thatA. brevisneither fractures nor fluidizes sediments, but instead uses a third mechanism, plastically rearranging sediment grains to create a burrow. The curvature of the undulating body fits meander geometry used to describe rivers, and changes in curvature driven by muscle contraction are similar for swimming and burrowing worms, indicating that the same gait is used in both sediments and water. Large calculated friction forces for undulatory burrowers suggest that sediment mechanics affect undulatory and peristaltic burrowers differently; undulatory burrowing may be more effective for small worms that live in sediments not compacted or cohesive enough to extend burrows by fracture.
Major urinary protein 5, a scent communication protein, is regulated by dietary restriction and subsequent re-feeding in mice
Authors: Giller K. , Huebbe P. , Doering F. , Pallauf K. , Rimbach G.
Published: February 2013

Major urinary proteins (Mups) are important for rodent scent communication and sexual behaviour. Recent evidence suggests that Mup1 may be regulated by fasting and re-feeding (RF). However, other Mup isoforms are poorly investigated, and data on the impact of long-term dietary restriction (DR) and ad libitum RF on Mup expression are missing. We investigated the effects of long-term 25 per cent DR and subsequent RF on Mup expression in male C57BL6 mice. DR significantly decreasedMupgene expression, hepatic and urinary protein levels compared with ad libitum (AL) fed control mice, with the greatest downregulation found for Mup5 expression. The decline in Mup expression was inverted by six months of RF. Because of inhibitory glucocorticoid response elements in the genomic sequence of theMup5gene, the observed inverse correlation of nuclear glucocorticoid receptor levels with Mup expression in response to DR and subsequent RF is a possible regulatory mechanism. Additionally, gene-expression-inhibiting histone deacetylation (H3K9) occurred in the region of theMup5gene in response to DR. We assume that Mup may act as a molecular switch linking nutritional status to sexual behaviour of mice, and thereby regulating male fertility and reproduction in response to food supply.
TheseirenaB Class Floral Homeotic Mutant of California Poppy (Eschscholzia californica) Reveals a Function of the Enigmatic PI Motif in the Formation of Specific Multimeric MADS Domain Protein Complexes
Authors: Lange Matthias , Orashakova Svetlana , Lange Sabrina , Melzer Rainer , Theißen Günter , Smyth David R. , Becker Annette
Published: February 2013

The products of B class floral homeotic genes specify petal and stamen identity, and loss of B function results in homeotic conversions of petals into sepals and stamens into carpels. Here, we describe the molecular characterization of seirena-1 (sei-1), a mutant from the basal eudicot California poppy (Eschscholzia californica) that shows homeotic changes characteristic of floral homeotic B class mutants. SEI has been previously described as EScaGLO, one of four B class–related MADS box genes in California poppy. The C terminus of SEI, including the highly conserved PI motif, is truncated in sei-1 proteins. Nevertheless, like the wild-type SEI protein, the sei-1 mutant protein is able to bind CArG-boxes and can form homodimers, heterodimers, and several higher order complexes with other MADS domain proteins. However, unlike the wild type, the mutant protein is not able to mediate higher order complexes consisting of specific B, C, and putative E class related proteins likely involved in specifying stamen identity. Within the PI motif, five highly conserved N-terminal amino acids are specifically required for this interaction. Several families lack this short conserved sequence, including the Brassicaceae, and we propose an evolutionary scenario to explain these functional differences.
Progressive Transverse Microtubule Array Organization in Hormone-InducedArabidopsisHypocotyl Cells
Authors: Vineyard Laura , Elliott Andrew , Dhingra Sonia , Lucas Jessica R. , Shaw Sidney L.
Published: February 2013

The acentriolar cortical microtubule arrays in dark-grown hypocotyl cells organize into a transverse coaligned pattern that is critical for axial plant growth. In light-grown Arabidopsis thaliana seedlings, the cortical array on the outer (periclinal) cell face creates a variety of array patterns with a significant bias (>3:1) for microtubules polymerizing edge-ward and into the side (anticlinal) faces of the cell. To study the mechanisms required for creating the transverse coalignment, we developed a dual-hormone protocol that synchronously induces ∼80% of the light-grown hypocotyl cells to form transverse arrays over a 2-h period. Repatterning occurred in two phases, beginning with an initial 30 to 40% decrease in polymerizing plus ends prior to visible changes in the array pattern. Transverse organization initiated at the cell's midzone by 45 min after induction and progressed bidirectionally toward the apical and basal ends of the cell. Reorganization corrected the edge-ward bias in polymerization and proceeded without transiting through an obligate intermediate pattern. Quantitative comparisons of uninduced and induced microtubule arrays showed a limited deconstruction of the initial periclinal array followed by a progressive array reorganization to transverse coordinated between the anticlinal and periclinal cell faces.
Entrepreneurial opportunity recognition: an empirical study of R&D personnel
Authors: Wang Yu‐Lin , Ellinger Andrea D. , Jim Wu Yen‐Chun
Published: February 2013

Purpose

The purpose of this paper is to examine the antecedents of, and the relationships between, entrepreneurial opportunity recognition, and individual‐level innovation performance.

Design/methodology/approach

Questionnaire data were collected from 268 senior R&D project team members (response rate 64.58 percent) along with 83 R&D managers who evaluated their employees' innovative behaviors in one science park in Taiwan.

Findings

The results show that an individual's self‐efficacy, prior knowledge, social networks, and perception about the industrial environment on opportunities all had positive effects on entrepreneurial opportunity recognition. Also entrepreneurial opportunity recognition contributed significantly to individual‐level innovation performance.

Research limitations/implications

The findings show that perception about the industrial environment on opportunities variable was the most important predictor among all four of the antecedents of entrepreneurial opportunity recognition. That is, individual characteristics and traits cannot fully explain the entrepreneurial opportunity recognition process. Because the data were limited to high technology industry, future studies need to validate these findings in other industries.

Practical implications

Findings of this study suggest that to increase R&D employee's innovation performance, it is critical for high technology firms to invest in developing and enhancing employees' entrepreneurial opportunity recognition ability.

Originality/value

The process of entrepreneurial opportunity recognition has been viewed as a black box. Although the literature has explored various antecedents that influence entrepreneurial opportunity recognition, there is limited empirical research that has examined the linkage between entrepreneurial opportunity recognition and potential outcome variables.
Environmental knowledge, unlearning, and performance in hospitality companies
Authors: Cegarra‐Navarro Juan‐Gabriel , Martinez‐Martinez Aurora , Ortega Gutiérrez Jaime , Luis Leal Rodríguez Antonio
Published: February 2013

Purpose

The Spanish hospitality industry is facing environmental challenges which require organisations and individuals to learn new skills and practices and create new environmental knowledge. The aim of this paper is to analyse the relationships between an unlearning context and environmental knowledge.

Design/methodology/approach

This paper analyses the relationships between an unlearning context and environmental knowledge and tries to identify whether environmental knowledge impacts on business outcomes through an empirical study of 127 Spanish hospitality companies.

Findings

The results support the hypothesis that, in order to create environmental knowledge and hence foster the application of new environmental knowledge, companies need to provide and support an unlearning context.

Research limitations/implications

It is important that managers provide an appropriate unlearning context to support the openness of individuals to new ideas and environmental awareness.

Originality/value

This study provides hotel managers with a better understanding of the relationship between environmental knowledge and organisational outcomes and highlights that managers need to provide and support an unlearning context, which is customised and based on three frameworks: the framework for examining the lens through which individuals view situations; the framework for changing individual habits and the framework for consolidating emergent understandings.
Ownership structure, capital structure, and performance of group affiliation
Authors: Shyu Jonchi
Published: February 2013

Purpose

This study seeks to examine how agency problems and internal capital markets in group‐affiliated firms are mutually influenced by the ownership structure, capital structure, and performance. It also aims to examine the endogeneity in group affiliation.

Design/methodology/approach

Using panel data, this study employs two‐stage least squares regression with the instrumental variable technique to examine the relationship among capital structure, ownership structure, and performance of group‐affiliated firms. Simultaneous equation models are constructed to identify the effects of interdependent decisions.

Findings

The empirical results indicate a U‐shaped relationship between insider ownership and performance. Moreover, the alignment of ownership and control rights determines the relationship between ownership structure and performance for group‐affiliated firms. The capital structure decisions of group‐affiliated firms are independent of firm performance and insider ownership, supporting the view that capital structure decisions of group‐affiliated firms are determined by the overall characteristics of the business group, rather than those of the individual firms.

Practical implications

Business groups can reduce the agency problems that occur in group affiliation by increasing the insider ownership (after a certain tunneling point), debt financing, and dividend payout.

Originality/value

Previous studies have paid little attention to the effects of the agency problem and the internal capital market on group affiliation. Whether endogeneity is a consequence of the common characteristics of group affiliation or a result of the simultaneity existing among ownership structure, capital structure, and performance is also unknown. This paper fills some of these gaps.