bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective fusion in adolescent idiopathic scoliosis: A radiographic evaluation of risk factors for imbalance
Authors: Studer D. , Awais A. , Williams N. , Antoniou G. , Eardley-Harris N. , Cundy P.
Published: April 2015

Study design

Retrospective database, chart and medical imaging review.

Objectives

To report on the outcome and evaluate possible risk factors for postoperative complications following selective spinal fusion in patients with adolescent idiopathic scoliosis (AIS).

Materials and methods

All patients with AIS who underwent either a selective thoracic or selective thoracolumbar/lumbar spinal fusion at our institution from January 2001 to December 2011 inclusive were included in this study. The minimum postoperative follow-up period of all patients was 2 years.

Results

During the 11-year study period, 157 patients with AIS underwent surgery for their progressive spinal deformity. Thirty patients (19 %) had a selective spinal fusion, with 16 patients (group A) having a selective thoracic, and 14 patients (group B) having a selective thoracolumbar/lumbar spinal arthrodesis. In both groups the main postoperative complications were adding-on (25 % group A, 36 % group B) and coronal decompensation (25 % group A, 29 % group B). In group A, no statistically significant risk factors for postoperative complications were identified. In group B, global coronal balance was identified as a significant risk factor for adding-on. Patients with adding-on had significantly higher coronal balance scores (mean 3.6) than those who did not experience adding-on (mean 1.9) ( p = 0.03). In addition, those with adding-on had a significantly smaller bending lumbar Cobb angle (mean 15) than those without adding-on (mean 31.6) ( p = 0.015). None of the patients who underwent selective spinal fusion required revision surgery.

Conclusion

Although the complication rate after performing a selective spinal fusion is high, the revision rate remains low and the debate whether or not to perform a selective spinal fusion will continue.
The reciprocal constitutive features of a Middle Eastern partnership: The Russian–Syrian bilateral relations
Authors: Tudoroiu Theodor
Published: April 2015

Using the concept of reciprocal socialization, this article argues that the Damascus–Moscow partnership has been since 1970 a reciprocal constitutive relation that has influenced considerably the actions, interests, and identities of the two partners. During the last two decades of the Cold War it represented an almost ideal-type example of a relationship between a super-power and its regional ally that, through its complex consequences, shaped significantly the two partners themselves, the Middle Eastern political and security environment, and the international system as a whole. Post-2003 developments and especially the present Syrian crisis also have influenced considerably the two states’ identity-building processes. After the US invasion of Iraq, the patterns of renewed bilateral cooperation have mirrored, at least in part, the Cold War ones. The Arab Spring enforced this trend. Yet, today the International Relations identity of Russia is quite different from the Soviet era one. The main consequence is that Moscow's new identity prevents it from supporting the regime in Damascus at any cost. If military operations take a turn threatening seriously the survival of that regime, it is likely that the Kremlin will not escalate its pro-al-Asad involvement, thus accepting the possible fall of its Middle Eastern ally.
Pannexin 1 facilitates arterial relaxation via an endothelium‐derived hyperpolarization mechanism
Authors: Gaynullina Dina , Shestopalov Valery I. , Panchin Yury , Tarasova Olga S.
Published: April 2015

Pannexin 1 (Panx1) is involved in endothelium‐dependent vasodilation in large arteries, but the exact mechanistic role remains poorly understood. We hypothesized that Panx1 facilitates large vessel relaxations regulating endothelium‐derived hyperpolarization (EDH)‐like mechanisms. The EDH‐like component of acetylcholine‐induced relaxation of saphenous arteries studied in isometric myograph after inhibition of NO‐synthase and cyclooxygenase was significantly impaired in mice with genetically ablated Panx1 (KO) relative to that in the wild type (WT) mice. Application of P1‐receptor antagonist and apyrase significantly reduced this component in WT, but not in KO mice, indicating participation of ATP released via Panx1 in the EDH‐like relaxation.
Mitsugumin 56 (hedgehog acyltransferase‐like) is a sarcoplasmic reticulum‐resident protein essential for postnatal muscle maturation
Authors: Van Bo , Nishi Miyuki , Komazaki Shinji , Ichimura Atsuhiko , Kakizawa Sho , Nakanaga Keita , Aoki Junken , Park Ki-Ho , Ma Jianjie , Ueyama Tomomi , Ogata Takehiro , Maruyama Naoki , Takeshima Hiroshi
Published: April 2015

Mitsugumin 56 (MG56), also known as the membrane‐bound O‐acyl‐transferase family member hedgehog acyltransferase‐like, was identified as a new sarcoplasmic reticulum component in striated muscle. Mg56‐knockout mice grew normally for a week after birth, but shortly thereafter exhibited a suckling defect and died under starvation conditions. In the knockout skeletal muscle, regular contractile features were largely preserved, but sarcoplasmic reticulum elements swelled and further developed enormous vacuoles. In parallel, the unfolded protein response was severely activated in the knockout muscle, and presumably disrupted muscle development leading to the suckling failure. Therefore, MG56 seems essential for postnatal skeletal muscle maturation.
Results of screening for cervical cancer among pregnant and non‐pregnant women in Brazil
Authors: Xavier‐Júnior José C.C. , Vale Diama B. , Vieira Luiz F.F. , Lima Marcelo T. , Zeferino Luiz C. , Dufloth Rozany M.
Published: April 2015

Objective

To compare cervical cytology test results among pregnant and non‐pregnant women, and to assess associations with age, screening history, and onset of sexual intercourse.

Methods

A retrospective analysis was conducted of cervical smears obtained from women aged 18–34 years in the Campinas region of Brazil between January 2000 and December 2009. Eligible participants had not undergone cytological screening within the previous year and had no history of precursor lesions or cervical cancer. Multinomial logistic regression was performed for different age groups, with high‐grade squamous intraepithelial lesions (HSILs) as the endpoint.

Results

Overall, 3072 (0.4%) of 861 353 non‐pregnant women and 135 (0.4%) of 37 568 pregnant women had HSILs. Odds of HSIL among pregnant and non‐pregnant women did not differ in any age group. An increased age at first sexual intercourse among pregnant women reduced odds of HSILs in all age groups (odds ratio 0.9 [95% confidence interval 0.8–0.9] for all). Among women aged 21–24 years, 25–29 years, and 30–34 years, some associations were identified between an interval of less than 5 years since previous screening and reduced odds of HSILs.

Conclusion

Mandatory cervical cytology screening does not seem to be necessary for pregnant women; protocols in place for non‐pregnant women should be followed.
Impact of the Baltimore Experience Corps Trial on cortical and hippocampal volumes
Authors: Carlson Michelle C. , Kuo Julie H. , Chuang Yi‐Fang , Varma Vijay R. , Harris Greg , Albert Marilyn S. , Erickson Kirk I. , Kramer Arthur F. , Parisi Jeanine M. , Xue Qian‐Li , Tan Eriwn J. , Tanner Elizabeth K. , Gross Alden L. , Seeman Teresa E. , Gruenewald Tara L. , McGill Sylvia , Rebok George W. , Fried Linda P.
Published: April 2015

Introduction

There is a substantial interest in identifying interventions that can protect and buffer older adults from atrophy in the cortex and particularly, the hippocampus, a region important to memory. We report the 2‐year effects of a randomized controlled trial of an intergenerational social health promotion program on older men's and women's brain volumes.

Methods

The Brain Health Study simultaneously enrolled, evaluated, and randomized 111 men and women (58 interventions; 53 controls) within the Baltimore Experience Corps Trial to evaluate the intervention impact on biomarkers of brain health at baseline and annual follow‐ups during the 2‐year trial exposure.

Results

Intention‐to‐treat analyses on cortical and hippocampal volumes for full and sex‐stratified samples revealed program‐specific increases in volumes that reached significance in men only (P's ≤ .04). Although men in the control arm exhibited age‐related declines for 2 years, men in the Experience Corps arm showed a 0.7% to 1.6% increase in brain volumes. Women also exhibited modest intervention‐specific gains of 0.3% to 0.54% by the second year of exposure that contrasted with declines of about 1% among women in the control group.

Discussion

These findings showed that purposeful activity embedded within a social health promotion program halted and, in men, reversed declines in brain volume in regions vulnerable to dementia.

Clinical Trial Registration: NCT0038.
The aqueous phase of Alzheimer's disease brain contains assemblies built from ∼4 and ∼7 kDa Aβ species
Authors: Mc Donald Jessica M. , O'Malley Tiernan T. , Liu Wen , Mably Alexandra J. , Brinkmalm Gunnar , Portelius Erik , Wittbold William M. , Frosch Matthew P. , Walsh Dominic M.
Published: April 2015

Introduction

Much knowledge about amyloid β (Aβ) aggregation and toxicity has been acquired using synthetic peptides and mouse models, whereas less is known about soluble Aβ in human brain.

Methods

We analyzed aqueous extracts from multiple AD brains using an array of techniques.

Results

Brains can contain at least four different Aβ assembly forms including: (i) monomers, (ii) a ∼7kDa Aβ species, and larger species (iii) from ∼30‐150 kDa, and (iv) >160 kDa. High molecular weight species are by far the most prevalent and appear to be built from ∼7 kDa Aβ species. The ∼7 kDa Aβ species resist denaturation by chaotropic agents and have a higher Aβ42/Aβ40 ratio than monomers, and are unreactive with antibodies to Asp1 of Ab or APP residues N‐terminal of Asp1.

Discussion

Further analysis of brain‐derived ∼7 kDa Aβ species, the mechanism by which they assemble and the structures they form should reveal therapeutic and diagnostic opportunities.
TAMIS with partial excision of mesorectum and primary closure of rectal wound using vloc
Authors: Alves Filho Eduardo Fonseca , de Oliveira Costa Paulo Frederico , de Carvalho Alexandre Lopes
Published: April 2015

Background Transanal Minimally Invasive Surgery has proven to be a viable alternative in the treatment of rectal tumors; however, rectal wound closure can be challenging. We describe our experience with this procedure using the vloc suture device.

Resume Eight successful Transanal Minimally Invasive Surgery with primary wound closure using vloc were performed in 5 men, 62 years mean age; all cases had pre-operative diagnosis of adenoma with high-grade dysplasia. The surgical anatomic–pathologic results showed 6 adenomas with high-grade dysplasia and 2 well differentiated adenocarcinomas, limited to the upper third of the submucosa (pT1SM1) without lymphatic or vascular invasion. All lesions were resected with negative margins. No patient reported during follow-up rectal pain, fecal incontinence or bleeding.

Conclusion The use of vloc in rectal wound closure during Transanal Minimally Invasive Surgery is secure and facilitates the procedure.
Ischemic Compression After Dry Needling of a Latent Myofascial Trigger Point Reduces Postneedling Soreness Intensity and Duration
Authors: Martín‐Pintado‐Zugasti Aitor , Pecos‐Martin Daniel , Rodríguez‐Fernández Ángel Luis , Alguacil‐Diego Isabel María , Portillo‐Aceituno Alicia , Gallego‐Izquierdo Tomás , Fernandez‐Carnero Josue
Published: April 2015

Objective

To investigate the effect of ischemic compression (IC) versus placebo and control on reducing postneedling soreness of 1 latent myofascial trigger point and on improving cervical range of motion (CROM) in asymptomatic subjects.

Design

A randomized, double‐blind, placebo‐controlled trial with 72‐hour follow‐up.

Setting

A university community.

Participants

Asymptomatic volunteers (N = 90: 40 men and 50 women) aged 18 to 39 years (mean ± standard deviation [SD]: 22 ± 3 years).

Intervention

All subjects received a dry needling application over the upper trapezius muscle. Participants were then randomly divided into 3 groups: a treatment group who received IC over the needled trapezius muscle, a placebo group who received sham IC, and a control group who did not receive any treatment after needling.

Main Outcome Measures

Visual analog scale (VAS; during needling, at posttreatment and 6, 12, 24, 48, and 72 hours) and CROM (at preneedling, postneedling, and 24 and 72 hours).

Results

Subjects in the IC group showed significantly lower postneedling soreness than the placebo and the control group subjects immediately after treatment (mean ± standard deviation [SD]: IC, 20.1 ± 4.8; placebo, 36.7 ± 4.8; control, 34.8 ± 3.6) and at 48 hours (mean ± SD: IC, 0.6 ± 1; placebo, 4.8 ± 1; control, 3.8 ± 0.7). In addition, subjects in the dry needling+IC group showed significantly lower postneedling soreness duration (P = .026). All subjects significantly improved CROM in contralateral lateroflexion and both homolateral and contralateral rotations, but only the improvements found in the IC group reached the minimal detectable change.

Conclusions

IC can potentially be added immediately after dry needling of myofascial trigger point in the upper trapezius muscle because it has the effect of reducing postneedling soreness intensity and duration. The combination of dry needling and IC seems to improve CROM in homolateral and contralateral cervical rotation movements.
The Application of Neuromuscular Electrical Stimulation Training in Various Non‐neurologic Patient Populations: A Narrative Review
Authors: Herzig David , Maffiuletti Nicola A. , Eser Prisca
Published: April 2015

In the last 2 decades, neuromuscular electrical stimulation has been used increasingly in deconditioned patients with the aim of increasing muscle force. Much basic research has been conducted in the area of increasing a muscle's fatigue resistance by neuromuscular electrical stimulation but similarly thorough research with regard to increasing maximal force is missing. Insufficient clinical and basic knowledge exists on the selection of stimulation parameters that will optimize muscle hypertrophy and gains in muscle force. For volitional training, established stimuli for muscle hypertrophy (which more or less parallels maximal muscle force) are muscle tension, metabolic stress, and muscle damage. The present review summarizes findings from clinical and basic research in terms of muscle mechanical as well as acute and chronic physiologic effects of different stimulation protocols, explains the role of the various stimulation parameters in determining the effect of NMES training protocols, and gives clinical recommendations for the choice of stimulation parameters for different patient populations with different training goals, such as increasing muscle force, mass, endurance, or energy consumption. We limit this review to non‐neurologic patients, because training goals of neurologic patients are specific to their functional deficits.
Feasibility of Lung Volume Recruitment in Early Neuromuscular Weakness: A Comparison Between Amyotrophic Lateral Sclerosis, Myotonic Dystrophy, and Postpolio Syndrome
Authors: Kaminska Marta , Browman Franceen , Trojan Daria A. , Genge Angela , Benedetti Andrea , Petrof Basil J.
Published: April 2015

Background

Lung volume recruitment (LVR) is a cough assistance technique used in persons with neuromuscular disorders (NMDs), most typically in those requiring noninvasive ventilation (NIV). Whether it may be useful in persons with NMDs who have milder respiratory impairment is unknown.

Objective

To assess the feasibility, impact on quality of life (QOL), and preliminary physiological effects of daily LVR in different categories of persons with NMDs who have an early stage of respiratory impairment.

Design

Feasibility study.

Setting

Academic tertiary care center.

Participants

Outpatients diagnosed with amyotrophic lateral sclerosis (n = 8), postpolio syndrome (n = 10), and myotonic dystrophy (n = 6) who had restrictive respiratory defects but were not yet using NIV.

Methods

Participants were asked to perform LVR up to 4 times daily and log their LVR use in a diary. Physiological measurements and questionnaires were completed at baseline and after 3 months.

Main Outcome Measurements

Compliance with LVR use was assessed, along with QOL and willingness to continue the treatment. Physiological measurements included forced vital capacity (FVC), lung insufflation capacity (LIC), and the LIC minus FVC difference.

Results

Of the 24 recruited subjects, 7 with amyotrophic lateral sclerosis, 7 with postpolio syndrome, and 5 with myotonic dystrophy completed the study (n = 19). At baseline, mean values for FVC and spontaneous peak cough flow were 59.9% predicted and 373.1 L/min, respectively. For subjects completing the study, 74% were willing to continue long‐term LVR use, and QOL scores were not adversely affected by LVR in any NMD subgroup. The LIC‐FVC difference increased from baseline to follow‐up by a mean of 0.243 L (P = .006) in all subjects (n = 19), suggesting a possible improvement in respiratory system mechanics.

Conclusions

In patients with NMDs who have early restrictive respiratory defects but do not yet require NIV, regular use of LVR is feasible with no negative impact on QOL over a 3‐month period and may have physiological benefits. Further work is needed to determine whether early institution of LVR can improve respiratory system mechanics and help delay ventilatory failure in persons with NMDs.
The politics and consequences of performance measurement
Authors: M. Lewis Jenny
Published: April 2015

Performance measurement is most often considered as the apolitical application of the use of information, collected and used to demonstrate effectiveness against a set of criteria. In reality, many complexities are hidden behind this seemingly rational and technical enterprise. This paper establishes a conceptual framework for the collection of articles in this volume. It examines the politics of performance measurement — who decides what should be measured, how, and why — and its consequences. It analyses why performance measurement is important, outlines its explicit and implicit purposes and the fundamental assumptions underpinning it, and describes its problems, paradoxes and consequences. A chain of performance measurement is then proposed and two contrasting versions of it (one rational-technical and one realistic-political) are presented. This social structural and political institutional approach to performance measurement highlights dynamics, interactivity and power. In doing so, it discloses the politics and consequences of performance measurement.
Reduction of Acute Shoulder Dislocations in a Remote Environment: A Prospective Multicenter Observational Study
Authors: Bokor-Billmann Therezia , Lapshyn Hryhoryi , Kiffner Erhard , Goos Matthias F. , Hopt Ulrich T. , Billmann Franck G.
Published: April 2015

Objective

Acute dislocations of the glenohumeral joint are common in wilderness activities. Emergent reduction should take place at the site of trauma to reduce the patient’s pain and the risk of vascular and neurological complications. A limited number of reduction methods are applicable in remote areas. The aim of this study is to present our method of reduction of anterior shoulder luxation that is easily applicable in remote areas without medication, adjuncts, and assistants and is well tolerated by patients.

Methods

A prospective observational study was conducted during a 5-year period. The patients included underwent closed manual reduction with our technique. After each reduction, the physician who performed the reduction completed a standardized detailed history, and reexamined the patient (for acute complications). The patients were contacted 6 months after the trauma to investigate long-term postreduction complications.

Results

Reduction was achieved with our method in 39 (100.0%) of 39 patients. The mean pain felt during our reduction procedure was rated 1.7 ± 1.4 (on a scale of 10) using the visual analog scale scoring system. No complications were noted before or after the reduction attempts. We did not find any long-term complications.

Conclusions

The reduction method presented in the present study is an effective method for the reduction of acute shoulder luxations in remote places. Our data suggest that this method could be applied for safe and effective reduction of shoulder dislocation.
Gleason Receives 2014 Mineral and Rock Physics Early Career Award
Authors:   AGU
Published: April 2015

Arianna Gleason received the 2014 Mineral and Rock Physics Early Career Award at the 2014 American Geophysical Union Fall Meeting, held 15–19 December in San Francisco, Calif. The award is for promising young scientists (current Ph.D. students and individuals who have completed the degree requirements for a Ph.D. or highest equivalent terminal degree up to 12 months prior to the nomination deadline) in recognition of outstanding contributions achieved during their Ph.D. research.
Oxidation of carbon monoxide in basic solution catalyzed by nickel cyano carbonyls under ambient conditions and the prototype of a CO-powered alkaline fuel cell
Authors: Lo Wenfeng , Hu Chunhua , Berenson Tyler , Tracer Nathaniel , Shlian Daniel , Khaloo Michael , Benhaim Avraham , Jiang Jianfeng
Published: April 2015

Nickel cyano carbonyl catalyzed carbon monoxide oxidation in basic solution under ambient conditions.
Auger recombination in sodium-iodide scintillators from first principles
Authors: McAllister Andrew , Åberg Daniel , Schleife André , Kioupakis Emmanouil
Published: April 2015

Scintillator radiation detectors suffer from low energy resolution that has been attributed to non-linear light yield response to the energy of the incident gamma rays. Auger recombination is a key non-radiative recombination channel that scales with the third power of the excitation density and may play a role in the non-proportionality problem of scintillators. In this work, we study direct and phonon-assisted Auger recombination in NaI using first-principles calculations. Our results show that phonon-assisted Auger recombination, mediated primarily by short-range phonon scattering, dominates at room temperature. We discuss our findings in light of the much larger values obtained by numerical fits to z-scan experiments.
Structural and magnetic properties of ferromagnetic Fe1−xSix (0.18 ≤ x ≤ 0.33) films formed by rapid thermal annealing on silicon-on-insulator substrates
Authors: Nakane R. , Sugahara S. , Tanaka M.
Published: April 2015

We systematically investigate the structural and magnetic properties of ferromagnetic Fe1−xSix (0.18 ≤ x ≤ 0.33) films formed by rapid thermal annealing (RTA) on silicon-on-insulator (SOI) substrates. During RTA of an Fe film deposited on a SOI substrate (consisting of a top Si layer, a buried oxide SiO2 layer, and a Si substrate), an Fe1−xSix film is synthesized by the thermal reaction of the deposited Fe film and the top Si layer, but the reaction is limited by the buried oxide layer in the SOI substrate, thus the Si concentration x in Fe1−xSix can be controlled by both the initial thicknesses of the Fe film and the top Si layer. A variety of characteristics show that single-phase Fe1−xSix (x = 0.18, 0.22, and 0.25) films with D03 + B2 structure are successfully obtained by choosing the optimum annealing temperature and time. Furthermore, the ordering fraction of D03 and B2 structures in these films is found to be more than 87%, indicating that the crystalline quality of these films is comparable to that of bulk Fe1−xSix materials reported so far. On the other hand, it is found that the Fe1−xSix (x = 0.33) film has Fe3Si and FeSi phases as in the case of bulk Fe1−xSix with x = 0.33. The film production technique and the quality of the ferromagnetic Fe1−xSix presented in this study are very attractive and useful for silicon-based spintronic devices which are compatible with the complementary metal-oxide-semiconductor technology.
Chaos, patterns, coherent structures, and turbulence: Reflections on nonlinear science
Authors: Ecke Robert E.
Published: April 2015

The paradigms of nonlinear science were succinctly articulated over 25 years ago as deterministic chaos, pattern formation, coherent structures, and adaptation/evolution/learning. For chaos, the main unifying concept was universal routes to chaos in general nonlinear dynamical systems, built upon a framework of bifurcation theory. Pattern formation focused on spatially extended nonlinear systems, taking advantage of symmetry properties to develop highly quantitative amplitude equations of the Ginzburg-Landau type to describe early nonlinear phenomena in the vicinity of critical points. Solitons, mathematically precise localized nonlinear wave states, were generalized to a larger and less precise class of coherent structures such as, for example, concentrated regions of vorticity from laboratory wake flows to the Jovian Great Red Spot. The combination of these three ideas was hoped to provide the tools and concepts for the understanding and characterization of the strongly nonlinear problem of fluid turbulence. Although this early promise has been largely unfulfilled, steady progress has been made using the approaches of nonlinear science. I provide a series of examples of bifurcations and chaos, of one-dimensional and two-dimensional pattern formation, and of turbulence to illustrate both the progress and limitations of the nonlinear science approach. As experimental and computational methods continue to improve, the promise of nonlinear science to elucidate fluid turbulence continues to advance in a steady manner, indicative of the grand challenge nature of strongly nonlinear multi-scale dynamical systems.
General multi-group macroscopic modeling for thermo-chemical non-equilibrium gas mixtures
Authors: Liu Yen , Panesi Marco , Sahai Amal , Vinokur Marcel
Published: April 2015

This paper opens a new door to macroscopic modeling for thermal and chemical non-equilibrium. In a game-changing approach, we discard conventional theories and practices stemming from the separation of internal energy modes and the Landau-Teller relaxation equation. Instead, we solve the fundamental microscopic equations in their moment forms but seek only optimum representations for the microscopic state distribution function that provides converged and time accurate solutions for certain macroscopic quantities at all times. The modeling makes no ad hoc assumptions or simplifications at the microscopic level and includes all possible collisional and radiative processes; it therefore retains all non-equilibrium fluid physics. We formulate the thermal and chemical non-equilibrium macroscopic equations and rate coefficients in a coupled and unified fashion for gases undergoing completely general transitions. All collisional partners can have internal structures and can change their internal energy states after transitions. The model is based on the reconstruction of the state distribution function. The internal energy space is subdivided into multiple groups in order to better describe non-equilibrium state distributions. The logarithm of the distribution function in each group is expressed as a power series in internal energy based on the maximum entropy principle. The method of weighted residuals is applied to the microscopic equations to obtain macroscopic moment equations and rate coefficients succinctly to any order. The model’s accuracy depends only on the assumed expression of the state distribution function and the number of groups used and can be self-checked for accuracy and convergence. We show that the macroscopic internal energy transfer, similar to mass and momentum transfers, occurs through nonlinear collisional processes and is not a simple relaxation process described by, e.g., the Landau-Teller equation. Unlike the classical vibrational energy relaxation model, which can only be applied to molecules, the new model is applicable to atoms, molecules, ions, and their mixtures. Numerical examples and model validations are carried out with two gas mixtures using the maximum entropy linear model: one mixture consists of nitrogen molecules undergoing internal excitation and dissociation and the other consists of nitrogen atoms undergoing internal excitation and ionization. Results show that the original hundreds to thousands of microscopic equations can be reduced to two macroscopic equations with almost perfect agreement for the total number density and total internal energy using only one or two groups. We also obtain good prediction of the microscopic state populations using 5-10 groups in the macroscopic equations.
Switching time in laser pulse heat-assisted magnetic recording using L1-FePt nanoparticles
Authors: Lyberatos A. , Weller D. , Parker G. J.
Published: April 2015

Atomistic spin model simulations using Langevin dynamics are performed to study the factors that determine the thermomagnetic recording time window in FePt media. The onset of thermomagnetic writing occurs at a temperature To larger than the Curie temperature Tc as a result of the finite time of relaxation of the magnetization by the linear reversal mode. The Bloch relaxation rate of magnetization growth during cooling below Tc is independent on the write field, provided the field is stronger than some threshold value. Application of a strong write field reduces switching time through better spin alignment in the paramagnetic regime. Finite size effects on the probability distribution of freezing temperatures Tf and the free energy provide insight on the thermomagnetic reversal mechanism. Constraints on the “pulse-mode” of recording when the head field reverses direction during cooling are also considered.
Fluid model of the sheath in front of a floating electrode immersed in a magnetized plasma with oblique magnetic field: Some comments on ion source terms and ion temperature effects
Authors: Gyergyek T. , Kovačič J.
Published: April 2015

A one-dimensional fluid model of the magnetized plasma-wall transition region in front of a floating electrode immersed in a magnetized plasma with oblique magnetic field is presented. The Boltzmann relation is assumed for the electrons, while the positive ions obey the ion continuity and momentum exchange equation. The ions are assumed to be isothermal. By comparison with a two-fluid model, it is shown that assuming the Boltzmann relation for the electrons implies that there is no creation or annihilation of the electrons. Consequently, there should not be any creation and annihilation of the positive ions either. The models that assume the Boltzmann relation for the electrons and a non-zero ion source term at the same time are therefore inconsistent, but such models have nevertheless been used extensively by many authors. So, in this work, an extensive comparison of the results obtained using the zero source term on one hand and three different non-zero source terms on the other hand is made. Four different ion source terms are considered in total: the zero source term and three different non-zero ion source terms. When the zero source term is used, the model becomes very sensitive to the boundary conditions, and in some cases, the solutions exhibit large amplitude oscillations. If any of the three non-zero ion source terms is used, those problems are eliminated, but also the consistency of the model is broken. The model equations are solved numerically in the entire magnetized plasma-wall transition region. For zero ion temperature, the model can be solved even if a very small ion velocity is selected as a boundary condition. For finite ion temperature, the system of equations becomes stiff, unless the ion velocity at the boundary is increased slightly above the ion thermal velocity. A simple method how to find a solution with a very small ion velocity at the boundary also for finite ion temperature in the entire magnetized plasma-wall transition region is proposed.
Photoelectron spectroscopy and theoretical studies of gaseous uranium hexachlorides in different oxidation states: UCl6q− (q = 0–2)
Authors: Su Jing , Dau Phuong D. , Liu Hong-Tao , Huang Dao-Ling , Wei Fan , Schwarz W. H. E. , Li Jun , Wang Lai-Sheng
Published: April 2015

Uranium chlorides are important in actinide chemistry and nuclear industries, but their chemical bonding and many physical and chemical properties are not well understood yet. Here, we report the first experimental observation of two gaseous uranium hexachloride anions, UCl6− and UCl62−, which are probed by photoelectron spectroscopy in conjunction with quantum chemistry calculations. The electron affinity of UCl6 is measured for the first time as +5.3 eV; its second electron affinity is measured to be +0.60 eV from the photoelectron spectra of UCl62−. We observe that the detachment cross sections of the 5f electrons are extremely weak in the visible and UV energy ranges. It is found that the one-electron one-determinental molecular orbital picture and Koopmans’ theorem break down for the strongly internally correlated U-5f2 valence shell of tetravalent U+4 in UCl62−. The calculated adiabatic and vertical electron detachment energies from ab initio calculations agree well with the experimental observations. Electronic structure and chemical bonding in the uranium hexachloride species UCl62− to UCl6 are discussed as a function of the oxidation state of U.
Sticking and splashing in yield-stress fluid drop impacts on coated surfaces
Authors: Blackwell Brendan C. , Deetjen Marc E. , Gaudio Joseph E. , Ewoldt Randy H.
Published: April 2015

Yield-stress fluids, including gels and pastes, are effectively fluid at high stress and solid at low stress. In liquid-solid impacts, the fluid motion can be halted by the yield stress at different points of the event, and these fluids can therefore stick and accumulate where they impact, motivating several applications of these rheologically complex materials. Here, we use high-speed imaging to experimentally study liquid-solid impact of yield-stress fluids on pre-coated horizontal surfaces. With a pre-coating of the same material, we can observe large long-lifetime ejection sheets with redirected momentum which extend away from the impact location. Under critical splash conditions, sheet breakup occurs and ejected droplets can be nonspherical and threadlike due to the inability of capillary stresses to deform material above a certain lengthscale. By varying the droplet size, impact velocity, surface coating thickness, and rheological material properties, we develop appropriate dimensionless parameters and present a low-dimensional regime map of impact behaviors.
A fast determination method for transverse relaxation of spin-exchange-relaxation-free magnetometer
Authors: Lu Jixi , Qian Zheng , Fang Jiancheng
Published: April 2015

We propose a fast and accurate determination method for transverse relaxation of the spin-exchange-relaxation-free (SERF) magnetometer. This method is based on the measurement of magnetic resonance linewidth via a chirped magnetic field excitation and the amplitude spectrum analysis. Compared with the frequency sweeping via separate sinusoidal excitation, our method can realize linewidth determination within only few seconds and meanwhile obtain good frequency resolution. Therefore, it can avoid the drift error in long term measurement and improve the accuracy of the determination. As the magnetic resonance frequency of the SERF magnetometer is very low, we include the effect of the negative resonance frequency caused by the chirp and achieve the coefficient of determination of the fitting results better than 0.998 with 95% confidence bounds to the theoretical equation. The experimental results are in good agreement with our theoretical analysis.
TaN interface properties and electric field cycling effects on ferroelectric Si-doped HfO2 thin films
Authors: Lomenzo Patrick D. , Takmeel Qanit , Zhou Chuanzhen , Fancher Chris M. , Lambers Eric , Rudawski Nicholas G. , Jones Jacob L. , Moghaddam Saeed , Nishida Toshikazu
Published: April 2015

Ferroelectric HfO2-based thin films, which can exhibit ferroelectric properties down to sub-10 nm thicknesses, are a promising candidate for emerging high density memory technologies. As the ferroelectric thickness continues to shrink, the electrode-ferroelectric interface properties play an increasingly important role. We investigate the TaN interface properties on 10 nm thick Si-doped HfO2 thin films fabricated in a TaN metal-ferroelectric-metal stack which exhibit highly asymmetric ferroelectric characteristics. To understand the asymmetric behavior of the ferroelectric characteristics of the Si-doped HfO2 thin films, the chemical interface properties of sputtered TaN bottom and top electrodes are probed with x-ray photoelectron spectroscopy. Ta-O bonds at the bottom electrode interface and a significant presence of Hf-N bonds at both electrode interfaces are identified. It is shown that the chemical heterogeneity of the bottom and top electrode interfaces gives rise to an internal electric field, which causes the as-grown ferroelectric domains to preferentially polarize to screen positively charged oxygen vacancies aggregated at the oxidized bottom electrode interface. Electric field cycling is shown to reduce the internal electric field with a concomitant increase in remanent polarization and decrease in relative permittivity. Through an analysis of pulsed transient switching currents, back-switching is observed in Si-doped HfO2 thin films with pinched hysteresis loops and is shown to be influenced by the internal electric field.
Incommensurate and commensurate modulations of Ba5RTi3Nb7O30 (R = La, Nd) tungsten bronzes and the ferroelectric domain structures
Authors: Mao Min Min , Li Kun , Zhu Xiao Li , Chen Xiang Ming
Published: April 2015

Incommensurate and commensurate structural modulations of Ba5RTi3Nb7O30 (R = La, Nd) tungsten bronze ceramics were investigated by using a cooling holder equipped transmission electron microscopy in the temperature range from 100 K to 363 K. The incommensurate modulation was observed in both Ba5LaTi3Nb7O30 and Ba5NdTi3Nb7O30 at room temperature, while there was a transition from incommensurate tilted structure to commensurate superstructure for Ba5NdTi3Nb7O30 with decreasing temperature. The incommensurate and commensurate modulations were determined by the A-site occupancy of Ba and R cations. The A-site disorder resulted in larger incommensurability parameter δ and the diffusion of the satellite reflection spots. The effect of A-site disorder on the coupling between long-range dipolar order and the commensurate modulation was also discussed. The obvious ferroelectric 180° domains with spike-like shape parallel to c axis were observed for Ba5NdTi3Nb7O30, while no macro ferroelectric domain was determined for Ba5LaTi3Nb7O30.
Current-induced motion in a skyrmion lattice
Authors: Martinez J. C. , Jalil M. B. A.
Published: April 2015

For a skyrmion lattice phase of chiral magnets, we compare predictions of the Landau-Lifshitz-Gilbert (LLG) and Thiele equations for the current-induced drift velocity for a given constant spin velocity. Instead of integrating the equations over a unit cell, we only perform an angle average, while retaining information on the radial dependence of velocity within the skyrmion. Since the skyrmion-lattice dynamics draws from magnetostatic, chiral, and exchange forces, we find that different scales are involved for the m = −1 and m = −2 skyrmions, a fact that might be useful in “tuning” scales of the drift velocity. We note that the Thiele equation yields less information than the LLG equation and explain why the translation mode has not yet been observed.
Evaluation of thermal gradients in longitudinal spin Seebeck effect measurements
Authors: Sola A. , Kuepferling M. , Basso V. , Pasquale M. , Kikkawa T. , Uchida K. , Saitoh E.
Published: April 2015

In the framework of the longitudinal spin Seebeck effect (LSSE), we developed an experimental setup for the characterization of LSSE devices. This class of device consists in a layered structure formed by a substrate, a ferrimagnetic insulator (YIG) where the spin current is thermally generated, and a paramagnetic metal (Pt) for the detection of the spin current via the inverse spin-Hall effect. In this kind of experiments, the evaluation of a thermal gradient through the thin YIG layer is a crucial point. In this work, we perform an indirect determination of the thermal gradient through the measurement of the heat flux. We developed an experimental setup using Peltier cells that allow us to measure the heat flux through a given sample. In order to test the technique, a standard LSSE device produced at Tohoku University was measured. We find a spin Seebeck SSSE coefficient of 2.8×10−7 V K−1.
Increased uniaxial perpendicular anisotropy in tetragonally distorted FeCo-Ti-N films
Authors: Matsuura Masashi , Tezuka Nobuki , Sugimoto Satoshi
Published: April 2015

Tetragonally distorted FeCo-Ti-N films were prepared on a Rh(001) underlayer. Uniaxial perpendicular anisotropy was observed for FeCo-Ti-N films with a thickness of 23.5 nm, and the c/a lattice distortion reached 1.08. The anisotropy constant (Ku) was estimated to be a minimum of 0.57 MJ·m−3 (5.7 × 106 ergs·cm−3). These results show that the combination of Ti and N additive elements could be effective for inducing lattice distortion in FeCo-based alloys on a Rh under layer, and that the lattice distortion increases Ku.
Variational method for the minimization of entropy generation in solar cells
Authors: Smit Sjoerd , Kessels W. M. M.
Published: April 2015

In this work, a method is presented to extend traditional solar cell simulation tools to make it possible to calculate the most efficient design of practical solar cells. The method is based on the theory of nonequilibrium thermodynamics, which is used to derive an expression for the local entropy generation rate in the solar cell, making it possible to quantify all free energy losses on the same scale. The framework of non-equilibrium thermodynamics can therefore be combined with the calculus of variations and existing solar cell models to minimize the total entropy generation rate in the cell to find the most optimal design. The variational method is illustrated by applying it to a homojunction solar cell. The optimization results in a set of differential algebraic equations, which determine the optimal shape of the doping profile for given recombination and transport models.
On quantifying the climate of the nonautonomous Lorenz-63 model
Authors: Daron J. D. , Stainforth D. A.
Published: April 2015

The Lorenz-63 model has been frequently used to inform our understanding of the Earth's climate and provide insight for numerical weather and climate prediction. Most studies have focused on the autonomous (time invariant) model behaviour in which the model's parameters are constants. Here, we investigate the properties of the model under time-varying parameters, providing a closer parallel to the challenges of climate prediction, in which climate forcing varies with time. Initial condition (IC) ensembles are used to construct frequency distributions of model variables, and we interpret these distributions as the time-dependent climate of the model. Results are presented that demonstrate the impact of ICs on the transient behaviour of the model climate. The location in state space from which an IC ensemble is initiated is shown to significantly impact the time it takes for ensembles to converge. The implication for climate prediction is that the climate may—in parallel with weather forecasting—have states from which its future behaviour is more, or less, predictable in distribution. Evidence of resonant behaviour and path dependence is found in model distributions under time varying parameters, demonstrating that prediction in nonautonomous nonlinear systems can be sensitive to the details of time-dependent forcing/parameter variations. Single model realisations are shown to be unable to reliably represent the model's climate; a result which has implications for how real-world climatic timeseries from observation are interpreted. The results have significant implications for the design and interpretation of Global Climate Model experiments.
2D attenuated total reflectance infrared spectroscopy reveals ultrafast vibrational dynamics of organic monolayers at metal-liquid interfaces
Authors: Kraack Jan Philip , Lotti Davide , Hamm Peter
Published: April 2015

We present two-dimensional infrared (2D IR) spectra of organic monolayers immobilized on thin metallic films at the solid liquid interface. The experiments are acquired under Attenuated Total Reflectance (ATR) conditions which allow a surface-sensitive measurement of spectral diffusion, sample inhomogeneity, and vibrational relaxation of the monolayers. Terminal azide functional groups are used as local probes of the environment and structural dynamics of the samples. Specifically, we investigate the influence of different alkyl chain-lengths on the ultrafast dynamics of the monolayer, revealing a smaller initial inhomogeneity and faster spectral diffusion with increasing chain-length. Furthermore, by varying the environment (i.e., in different solvents or as bare sample), we conclude that the most significant contribution to spectral diffusion stems from intra- and intermolecular dynamics within the monolayer. The obtained results demonstrate that 2D ATR IR spectroscopy is a versatile tool for measuring interfacial dynamics of adsorbed molecules.
Passive shielding effect on space profile of magnetic field emissions for wireless power transfer to vehicles
Authors: Batra T. , Schaltz E.
Published: April 2015

Magnetic fields emitted by wireless power transfer systems are of high importance with respect to human safety and health. Aluminum and ferrite are used in the system to reduce the fields and are termed as passive shielding. In this paper, the influence of these materials on the space profile has been investigated with the help of simulations on Comsol for the four possible geometries—no shielding, ferrite, aluminum, and full shielding. As the reflected impedance varies for the four geometries, the primary current is varied accordingly to maintain constant power transfer to the secondary side. Surrounding magnetic field plots in the vertical direction show that maxima's of the two coils for the no shielding geometry are centered at the respective coils and for the remaining three are displaced closer to each other. This closeness would lead to more effective addition of the two coil fields and an increase in the resultant field from space point of view. This closeness varies with distance in the horizontal direction and vertical gap between the coils and is explained in the paper. This paper provides a better understanding of effect of the passive shielding materials on the space nature of magnetic fields for wireless power transfer for vehicle applications.