bluuebunny/crossref_metadata_2025 huggingface dataset:
Treatment of femur fractures in children with cerebral palsy
Authors: Leet Arabella I. , Shirley Eric D. , Barker Chris , Launay Franck , Sponseller Paul D.
Published: August 2009

Purpose

Children with cerebral palsy may have low bone density stemming from various etiologies and are, thereby, at risk for fractures. The treatment of femur fractures in children with cerebral palsy may need to be tailored to address the management of spastic muscle tone and multiple medical co-morbidities.

Methods

Our study is a retrospective review that evaluates the treatment of 47 femur fractures in children with cerebral palsy in both ambulatory and non-ambulatory patients.

Results

Thirty-two fractures in non-ambulators were treated non-operatively, 11 of which resulted in malunions and five developed pressure sores. Six fractures in non-ambulators were treated operatively, one of which resulted in a malunion. In ambulators, five fractures were treated non-operatively; one of these fractures lost reduction after 2 weeks and required surgical intervention. One of four fractures in ambulators treated operatively developed a malunion.

Conclusion

Our study results suggest that femur fractures in children with cerebral palsy can be treated non-operatively; however, because of the high risk of malunion in this patient population, fracture alignment needs to be followed closely during healing. Careful attention during casting is necessary to prevent pressure sores. Strong consideration should be given to initial operative treatment in ambulatory patients in order to preserve function.
Diagnosis and treatment methods for recurrent miscarriage cases
Authors: Sugiura‐Ogasawara Mayumi , Ozaki Yasuhiko , Kitaori Tamao
Published: August 2009

Recurrent miscarriage is classically defined as three or more consecutive pregnancy losses. Established causes of recurrent miscarriage are antiphospholipid antibodies, uterine anomalies and abnormal chromosomes in either partner, particularly translocations. Embryonic aneuploidy is the most important cause of miscarriage before 10 weeks’ gestation. It can be speculated that about 51% of patients with a history of three miscarriages experienced these because of abnormal embryonic karyotypes. It is not necessary to give any medication for such cases caused by an abnormal embryonic karyotype. Psychological tender loving care might be the most important requirement to continue conceiving till live birth results.
Effects of fluticasone propionate dosage in an experimental model of feline asthma
Authors: Cohn Leah A , DeClue Amy E. , Cohen Rachael L , Reinero Carol R.
Published: August 2009

Cats with inflammatory bronchial disease are usually treated with glucocorticoid (GC) drugs to reduce airway inflammation. Inhalant GC delivery can preserve airway effects while systemic effects are minimized. An appropriate dosage regimen for inhaled GC in cats has not been investigated. A blinded, randomized, cross-over study design was used to investigate the ability of three different dosages of the inhalant GC fluticasone propionate delivered by metered dose inhaler to ameliorate eosinophilic airway inflammation in cats with experimentally induced allergic airway inflammation. Further, suppression of the hypothalamic–pituitary–adrenal axis (HPAA) at each dose was assessed. Fluticasone administered at dosages of 44, 110, or 220 μg q 12 h reduced airway eosinophilia by 74%, 82%, or 81%, respectively (no difference). None of the dose regimens tested caused HPAA suppression. We conclude that a twice daily dosage of 44 μg fluticasone should be evaluated for the management of cats with naturally occurring inflammatory bronchial disease.
Positive contrast peritoneography in the diagnosis of a pleuroperitoneal diaphragmatic hernia in a cat
Authors: Parry Andrew
Published: August 2009

A young adult entire male domestic shorthair cat was presented with a known history of a road traffic accident. Survey radiographs suggested a congenital diaphragmatic hernia unrelated to the recent trauma. Positive contrast peritoneography was undertaken and findings were consistent with a pleuroperitoneal diaphragmatic hernia (or true hernia). This was repaired surgically and was thought to be an incidental finding. This case report demonstrates the use of positive contrast peritoneography as a simple and effective tool in the diagnosis of pleuroperitoneal diaphragmatic hernias.
The primary plan of the Battersea Shield
Authors: Stevick Robert D
Published: August 2009

The decorative motifs of palmettes and interlocking S-patterns on the Battersea Shield have a clear place in a well-understood tradition of Celtic art, while the plan of the shield – its schema – has not had such a place. Its essential form is a deliberately constructed configuration crafted specifically by a constructional geometry, within a tradition which persisted and later pervaded Insular art.
Spontaneous pneumomediastinum: benefits of contrast computed tomography imaging
Authors: Hoskison E , Judd O , Dickinson E , Vaidhyanath R , Pau H
Published: August 2009

Objective:

We report a case of spontaneous pneumomediastinum presenting with chest and anterior neck pain.

Method:

The clinical findings, differential diagnosis and selection of radiological investigations are discussed.

Results:

Spontaneous pneumomediastinum is an uncommon condition usually presenting in young patients. Presentation to the otolaryngology department occurs due to the presence of symptoms such as neck pain. Differential diagnoses must be considered and excluded, using the clinical features and the results of radiological investigation. Once the diagnosis is confirmed, conservative management is undertaken.

Conclusion:

Spontaneous pneumomediastinum is uncommon and the clinical features are variable. The recommended investigation is a computed tomography scan with orally administered, water soluble contrast to exclude important differential diagnoses and thus enable definitive diagnosis.
Treatment results for ethmoid sinus carcinoma
Authors: Gras-Cabrerizo J R , Montserrat-Gili J R , León-Vintró X , Massegur-Solench H , de Vega J M , Virós-Porcuna D
Published: August 2009

Objective:

The aim of this study was to describe the results of treatment in patients with ethmoid sinus carcinoma.

Materials and method:

We performed a retrospective study of 34 patients with carcinoma of the ethmoid sinus, and collected the following data: age, sex, employment, tobacco and alcohol consumption, tumour-node-metastasis stage, treatment, and survival.

Results:

The mean patient age was 64 years. Seventy-six per cent of patients were men and 24 per cent women. Squamous cell carcinoma was the most frequent histological tumour type (44 per cent). Eleven patients were classified as T2, six as T3, six as T4a and 11 as T4b. Two patients (6 per cent) had nodal metastasis at the time of diagnosis. The anterior skull base was involved in 17 patients (50 per cent) and the anterior orbital contents were affected in seven patients (21 per cent). The five-year actuarial observed survival rate for all patients was 44 per cent.

Conclusions:

Combined treatment with surgery and post-operative radiotherapy permitted good local control in patients with ethmoid sinus carcinoma. We do not recommend prophylactic neck treatment for ethmoid sinus carcinoma.
Intracranial hypertension secondary to sigmoid sinus compression by group A streptococcal epidural abscess
Authors: Ludemann J P , Poskitt K , Singhal A
Published: August 2009

Objective:

We present an extremely rare case of severe intracranial hypertension secondary to sigmoid sinus compression by a group A streptococcal epidural abscess.

Method:

Case report and review of the world literature.

Results:

A five-year-old boy was treated for acute otitis media and group A streptococcal bacteraemia, but subsequently developed severe intracranial hypertension. Computed tomography revealed that, although the sigmoid sinuses were not thrombosed, the patient had a dominant right sigmoid sinus that was almost completely compressed by a small epidural abscess. After surgical decompression of the epidural abscess, with aggressive debridement of the granulation tissue from the sigmoid sinus wall, the patient awoke from general anaesthesia with complete resolution of his symptoms and signs of intracranial hypertension. He suffered no sequelae over the subsequent six months' follow up.

Conclusion:

This is the first reported case of intracranial hypertension due to an epidural abscess causing sigmoid sinus compression without thrombosis. This case illustrates the fact that, even in the absence of thrombosis of the sigmoid sinus, a small epidural abscess may require urgent surgical treatment.
Juvenile green turtles (Chelonia mydas) in the effluent discharge channel of a steel plant, Espírito Santo, Brazil, 2000–2006
Authors: Torezani Evelise , Baptistotte Cecília , Mendes Sérgio L. , Barata Paulo C.R.
Published: August 2009

This study, carried out from August 2000 to July 2006, began out of the recognition of a special ecological situation, when an aggregation of juvenile green turtles (Chelonia mydas) was found inside the effluent discharge channel of a steel plant located near Vitória, the State of Espírito Santo capital, eastern Brazil. The green turtles were captured through either cast nets or a set net or by hand (one turtle was captured alive on one of the channel banks); after data collection, they were released back into the discharge channel. Information is here reported on the temporal pattern of occurrence, size-classes, residency, presence of tumours and growth rates of tumoured and non-tumoured green turtles in the study area. A total of 640 individual green turtles were captured in the six years; 448 of them were captured just once, and 192 were captured two or more times. Curved carapace length ranged between 25.2 and 77.5 cm. Among the captured green turtles, 59.1% were classified as being in normal body condition and without any tumours, 6.6% were either underweight or emaciated but without any tumours, and 34.4% had tumours, with different levels of the tumour severity score.
A new deep-sea species of Mitromorpha (Gastropoda: Conoidea: Conidae) off Brazil
Authors: Lima Silvio Felipe Barbosa , Barros José Carlos Nascimento , Francisco Jonata de A.
Published: August 2009

A new species of Conidae is described from Brazilian waters. Mitromorpha santosi sp. nov. from the Continental Slope off the state of Rio Grande do Norte (north-east Brazil: 04°50′60″–04°51′40″s, 35°06′01″–35°06′46″W) is compared with M. biplicata (western Atlantic), M. usta (eastern Atlantic), M. dalli (north-eastern Atlantic), M. popeae (West Indies), M. undulate (West Indies) and two unnamed Brazilian species being diagnosed as possessing strong axial ribs, second spiral cord on the body whorl more pronounced and yellowish-brown spiral bands. In addition, a lectotype for Mitromorpha undulata, is designated herein.
The malaria merozoite, forty years on
Authors: BANNISTER L. H. , MITCHELL G. H.
Published: August 2009

The invasive blood stage of malaria parasites, merozoites, are complex entities specialized for the capture and entry of red blood cells. Their potential for vaccination and other anti-malaria strategies have attracted much research attention over the last 40 years, and there is now a considerable body of data relating to their biology. In this article some of the major advances over this period and remaining challenges are reviewed.
Strong bounded operators for ergodic averages and Lebesgue derivatives
Authors: LIU CHAOYUAN
Published: August 2009

The goal of this article is to give a new proof of there being strong type (p,p) bounds, for anypwith 1>p>∞, for the class of square functions, oscillation operators and variation operators that arise when considering multiparameter differentiation and multiparameter ergodic averages. The method of proof is to first show that there is a strong estimate fromL∞toBMOfor these operators in the case of multiparameter differentiation; then, by using known weak (1, 1) estimates and interpolation, one obtains strong bounds for these operators in the case of multiparameter differentiation. It follows from applying the Calderón transfer principle that these operators are of strong type (p,p), for all 1>p>∞, for the corresponding multiparameter ergodic averages.
Habitat-related germination behaviour and emergence phenology in the woodland geophyte Anemone ranunculoides L. (Ranunculaceae) from northern Italy
Authors: Mondoni Andrea , Probert Robin , Rossi Graziano , Hay Fiona
Published: August 2009

This study examined whether the restricted habitat preference of the spring-flowering woodland geophyte Anemone ranunculoides L., compared with that of A. nemorosa growing in the same woodlands in northern Italy, could be explained by subtle differences in germination preference and emergence phenology. Immediately after harvest, seeds of A. ranunculoides were either sown on agar in the laboratory under simulated seasonal temperatures or placed in nylon mesh sachets and buried in the wild. Embryos, undifferentiated at the time of seed dispersal, grew during summer in the laboratory and in the wild, culminating in radicle emergence in the autumn, when temperatures fell to c. 15°C. Shoot emergence was delayed under natural conditions until soil temperature had dropped further to c. 10°C. Compared with populations of the closely related Anemone nemorosa L. occupying the same woodland habitat, which have been reported to have non-dormant radicles, A. ranunculoides displayed a narrower temperature tolerance for radicle emergence and high levels of germination were possible only after prolonged exposure to summer conditions, indicating physiological dormancy. However, unlike A. nemorosa, shoot emergence in A. ranunculoides was not dependent on winter temperatures, suggesting weaker epicotyl morphophysiological dormancy. Under a regime of diurnal temperature alternation, simulating the microclimate where there is little plant cover, germination failed almost completely; this could explain the absence of A. ranunculoides in open habitats.
NEGATING OPERA THROUGH OPERA: COSÌ FAN TUTTE AND THE REVERSE OF THE ENLIGHTENMENT
Authors: LÜTTEKEN LAURENZ
Published: August 2009

Among the operas on which Mozart and Da Ponte collaborated, Così fan tutte is a special case. In some ways, the libretto is more conventional than those provided for Le nozze di Figaro or Don Giovanni, and Mozart was not the first composer asked to set it. To understand the work best, it is necessary to read the text closely. This article concentrates on a few, highly significant characteristics – in particular, the locations in which the opera takes place. Such details provide the foundations for surprising insights into the opera. First, the libretto deals with central issues in eighteenth-century aesthetics, but the mechanist philosophy that informs the plot (reminiscent of that theorized by Julien Offray de La Mettrie in L'Homme machine) defuses these issues over the course of the action. Secondly, the music that turns the libretto into an opera resonates with specialist issues of eighteenth-century music aesthetics, often to turn them, once again, on their heads. In the last analysis, Così fan tutte is an opera in which both text and music question truth and reliability, and the consequences are serious for the opera, for music and for the very Enlightenment itself.
MUSIC AND ‘MUSIC’ IN EIGHTEENTH-CENTURY META-OPERATIC SCORES
Authors: BELLINI ALICE
Published: August 2009

‘Meta-operas’, that is, operas portraying the world of opera and its protagonists (such as impresarios, music directors, librettists and virtuosi), became increasingly common during the eighteenth century. Most of the scholarly literature on meta-opera, however, concentrates on the operas' poetic texts, their librettos. Scholars have dealt with these operas about operas almost as though they were spoken dramas, without taking into account the many ways in which metatheatrical practices and conventions are made more complex by the presence of music.

What do meta-operatic scores look like? Are they similar to other ‘ordinary’ scores of the same time, or do their metatheatrical techniques set them aside as special? Considering a number of eighteenth-century works, this article points out how specific musical means can contribute to the overall effect of meta-operatic plots: the stratified nature of meta-narratives is, in fact, mirrored in the scores when realistic music is performed on stage. On these occasions, the presence of more than one layer of musical performance (of music and ‘music’) can be detected in the score. Furthermore, the presence of realistic music allows for a highly flexible treatment of standard operatic practices, and a number of passages work across conventional oppositions such as recitative/closed number, ‘real-life’/‘performed’ and ‘spoken’/‘sung’. Meta-operas, therefore, offer a special perspective on the presence of realistic music in opera.
Die Rechte von Angehörigen urteilsunfähiger Personen
Authors: Baumann Max
Published: August 2009

Wird jemand aus gesundheitlichen Gründen urteilsunfähig, gehen seine Angehörigen in der Regel davon aus, dass ihnen kraft ihrer Verwandtschaft bezüglich der medizinischen Behandlung umfassende Informations- und (Mit-) Entscheidungsrechte zustehen. Dem ist jedoch meistens nicht so. Wie zu zeigen sein wird, genügt heute eine verwandtschaftliche Beziehung allein nicht mehr, derartige Rechte zu begründen.
Die Beziehung zum interdisziplinären Behandlungsteam aus Sicht nierentransplantierter Jugendlicher
Authors: Kleinknecht Michael , Neuhaus Thomas J. , Gehring Thomas M. , Landolt Markus A.
Published: August 2009

Verschiedene Studien haben gezeigt, dass eine von chronisch kranken Jugendlichen als unterstützend erlebte professionelle Beziehung ihre Adhärenz verbessert. Ihr Erleben der professionellen Beziehung im interdisziplinären Behandlungskontext wurde bisher erst wenig untersucht. Am Beispiel nierentransplantierter Jugendlicher wurde mit dieser Studie aufgezeigt, wie die Jugendlichen die Qualität der Beziehung zu den Angehörigen der verschiedenen Berufsgruppen erleben. Dazu wurden 27 Jugendliche im Alter von 12 bis 18 Jahren mit dem Familiensystemtest (FAST) im Rahmen der deskriptiven Querschnittserhebung befragt. Die Auswertung zeigte, dass die pädiatrisch-nephrologisch spezialisierten Pflegefachfrauen gemeinsam mit den Ärzten für die Jugendlichen in vergleichbarer Weise wichtige Bezugspersonen sind. Die Pflegefachfrauen stehen ihnen dabei emotional näher, während der Einfluss der Ärzte auf Verhaltensentscheidungen der Jugendlichen größer ist. Die Jugendlichen wünschen sich jedoch mit den Pflegefachfrauen und den Ärzten eine gleichermaßen professionell-freundschaftliche, wenig hierarchische Beziehung. Die Ergebnisse weisen darauf hin, dass sich das am Universitäts-Kinderspital Zürich etablierte, auf spezifische Patientengruppen ausgerichtete pflegerische Bezugspersonenkonzept bewährt und die interdisziplinäre Zu­sammenarbeit bei der Betreuung chronisch krankter Jugendlicher wichtig ist.
Spatial and temporal features of ENSO meridional scales
Authors: Zhang Wenjun , Li Jianping , Jin Fei‐Fei
Published: August 2009

The spatial and temporal features of the El Niño/Southern Oscillation (ENSO) meridional scales are investigated using the Hadley Center Global Sea Ice and Sea Surface Temperature (HadISST) data for the period of 1950–2007. The results show that the meridional scales of the ENSO warm and cold events are asymmetric and exhibit interdecadal changes. The meridional extent of the sea surface temperature anomalies (SSTA) during La Niña years is wider than that during El Niño years. This is because strengthened trades and thus strengthened upwelling and meridional currents during La Niña events more effectively spread SSTA away from the equator. With the Walker Circulation weakening in recent decades, which tends to reduce upwelling and meridional currents over the central and eastern equatorial Pacific, the meridional scales of both El Niño and La Niña events also decrease.
Quantitative MRI and MR Spectroscopy of Multiple Sclerosis, Alzheimer’s Disease, Epilepsy and Cancer Microimaging Techniques
Authors: Sharma Rakesh
Published: August 2009

Clinical MRI and MRS have promise in molecular imaging. Microimaging techniques offer a promising research tool to get noninvasive data in monitoring the effect of drugs.
OntoFox:
Authors: Xiang Zuoshuang , He Yongqun
Published: August 2009

OntoFox ("http://ontofox.hegroup.org/":http://ontofox.hegroup.org/) is a web server that facilitates ontology development by automatically fetching ontology terms and their annotations from existing ontologies and saving the results in importable RDF/OWL format. OntoFox is developed based on the MIREOT principle. Currently OntoFox can fetch ontology annotations from >10 existing ontologies. OntoFox provides an efficient approach to promote ontology sharing and interoperability.
Towards Desiderata for an Ontology of Diseases for the Annotation of Biological Datasets
Authors: Bodenreider Olivier , Burgun Anita
Published: August 2009

There is a plethora of disease ontologies available, all potentially useful for the annotation of biological datasets. We define seven desirable features for such ontologies and examine whether or not these features are supported by eleven disease ontologies. The four ontologies most closely aligned with our desiderata are Disease Ontology, SNOMED CT, NCI thesaurus and UMLS.
Effects of insulin resistance on endothelial progenitor cells and vascular repair
Authors: Cubbon Richard M. , Kahn Matthew B. , Wheatcroft Stephen B.
Published: August 2009

Insulin resistance, a key feature of obesity, the metabolic syndrome and Type 2 diabetes mellitus, results in an array of metabolic and vascular phenomena which ultimately promote the development of atherosclerosis. Endothelial dysfunction is intricately related to insulin resistance through the parallel stimulatory effects of insulin on glucose disposal in metabolic tissues and NO production in the endothelium. Perturbations characteristic of insulin resistance, including dyslipidaemia, inflammation and oxidative stress, may jeopardize the structural or functional integrity of the endothelium. Recent evidence suggests that endothelial damage is mitigated by endogenous reparative processes which mediate endothelial regeneration. EPCs (endothelial progenitor cells) are circulating cells which have been identified as mediators of endothelial repair. Several of the abnormalities associated with insulin resistance, including reduced NO bioavailability, increased production of ROS (reactive oxygen species) and down-regulation of intracellular signalling pathways, have the potential to disrupt EPC function. Improvement in the number and function of EPCs may contribute to the protective actions of evidence-based therapies to reduce cardiometabolic risk. In the present article, we review the putative effects of insulin resistance on EPCs, discuss the underlying mechanisms and highlight potential therapeutic manoeuvres which could improve vascular repair in individuals with insulin resistance.
Pinning at template feature edges for step and flash imprint lithography
Authors: Chauhan Siddharth , Palmieri Frank , Bonnecaze Roger T. , Willson C. Grant
Published: August 2009

We present a theory of the pinning of an air-liquid interface at the feature edge of a template during the imprint step of step and flash imprint lithography (SFIL). Pinning occurs when the pressure at the air-liquid interface reaches the pressure of the bulk liquid. At this condition, there is no pressure gradient or driving force to move the liquid and fill the feature. We examined several parameters, including residual layer thickness, wettability of the feature edge, applied force on the template, and the radius of curvature of the feature edge, to study their effect on pinning. An optimal SFIL process window and template modifications are proposed that minimize the pinning at the feature edge while still preventing any extrusion along the mesa (pattern containing area on the template) edge.
New technology enables high precision multislit collimators for microbeam radiation therapy
Authors: Bräuer-Krisch E. , Requardt H. , Brochard T. , Berruyer G. , Renier M. , Laissue J. A. , Bravin A.
Published: August 2009

During the past decade microbeam radiation therapy has evolved from preclinical studies to a stage in which clinical trials can be planned, using spatially fractionated, highly collimated and high intensity beams like those generated at the x-ray ID17 beamline of the European Synchrotron Radiation Facility. The production of such microbeams typically between 25 and 100 μm full width at half maximum (FWHM) values and 100–400 μm center-to-center (c-t-c) spacings requires a multislit collimator either with fixed or adjustable microbeam width. The mechanical regularity of such devices is the most important property required to produce an array of identical microbeams. That ensures treatment reproducibility and reliable use of Monte Carlo-based treatment planning systems. New high precision wire cutting techniques allow the fabrication of these collimators made of tungsten carbide. We present a variable slit width collimator as well as a single slit device with a fixed setting of 50 μm FWHM and 400 μm c-t-c, both able to cover irradiation fields of 50 mm width, deemed to meet clinical requirements. Important improvements have reduced the standard deviation of 5.5 μm to less than 1 μm for a nominal FWHM value of 25 μm. The specifications of both devices, the methods used to measure these characteristics, and the results are presented.
The resolution of the identity approximation applied to the correlation consistent composite approach
Authors: Prascher Brian P. , Lai Jeremy D. , Wilson Angela K.
Published: August 2009

A new implementation of the correlation consistent composite approach (ccCA), denoted RI-ccCA, utilizing both the resolution of the identity (RI) and local methods is presented. A set of 102 molecules composed of first and second row, main group atoms is employed to compare total energies, atomization energies, and enthalpies of formation between the original ccCA implementation and those of RI-ccCA. Relative CPU time and disk space requirements of RI-ccCA as compared to ccCA, demonstrate that on the average, employing the RI approximation in ccCA affords CPU time savings over 70% and disk space requirements diminished by well over 90% without introducing significant error in energetic properties.
Effect of anode shape on correlation of neutron emission with pinch energy for a 2.7kJ Mather-type plasma focus device
Authors: Hussain S. S. , Ahmad S. , Murtaza Ghulam , Zakaullah M.
Published: August 2009

Correlation of neutron emission with pinch energy for a Mather-type plasma focus energized by a single capacitor 12.5μF, 21kV (2.7kJ) is investigated by employing time resolved and time integrated detectors for two different anode shapes. The maximum average neutron yield of about 1.3×108 per shot is recorded with cylindrical anode, that increases to 1.6×108 per shot for tapered anode. At optimum pressure the input energy converted to pinch energy is about 24% for cylindrical anode as compared to 36% for tapered anode. It is found that the tapered anode enhances neutron flux about 25±5% both in axial and radial directions and also broadens the pressure range for neutron emission as well as pinch energy. The neutron yield and optimum gas filling pressures are found strongly dependent on the anode shape.
Multiple adsorption of NO on cobalt-exchanged chabazite, mordenite, and ferrierite zeolites: A periodic density functional theory study
Authors: Georgieva Ivelina , Benco Lubomir , Tunega Daniel , Trendafilova Natasha , Hafner Jürgen , Lischka Hans
Published: August 2009

The adsorption of NO on Co(II)-exchanged chabazite (CHA), mordenite (MOR), and ferrierite (FER) has been investigated by periodic density functional theory calculations. The most stable configurations of Co(II) in α and β sites of the zeolites with two framework Al/Si substitutions at short distances and Al–(Si)n>1–Al ordering are used for calculating the adsorption energy of NO molecules on Co(II) cations and at Al framework sites. The less stable configurations of α-Co(II)-MOR/FER show larger adsorption energies for one and two NO molecules. The bonding of one, two (and three) NO molecules to α/β-Co(II) sites in CHA/MOR/FER induces a shortening of the N–O bond lengths because electron density is withdrawn from the antibonding orbital of the adsorbed NO molecule. The calculated ν(NO) stretching frequencies of mono- and dinitrosyl complexes at α/β-Co(II)-MOR/FER are in good agreement with the experimental data. NO molecules adsorbed on α-Co(II)-MOR and on α-Co(II)-FER show similar NO stretching frequencies as nitrosyl complexes in Co(II)-MOR/-FER/-ZSM-5. Mononitrosyl complexes of α/β-Co(II)-MOR/FER display ν(NO) frequencies blueshifted relative to the free NO, while in dinitrosyl complexes both the symmetric and asymmetric components are redshifted compared to the mononitrosyl frequency. The analysis of the vibrational spectra suggests that mononitrosyls are formed by adsorption at cation in both α and β sites in MOR, FER, and ZSM-5, while dinitrosyl complexes exist only at α-type Lewis sites. This is important for the understanding of the reduction mechanism of NO to N2. A larger adsorption capacity of α-Co(II)-FER compared to α-Co(II)-MOR is predicted.
Nonequilibrium separation of short DNA using nanoslit arrays
Authors: Strychalski Elizabeth A. , Lau Henry W. , Archer Lynden A.
Published: August 2009

A nonequilibrium regime of size-based separation was observed experimentally for double-stranded deoxyribonucleic acid (DNA) molecules with lengths below 1 kbp moving electrokinetically through nanofluidic nanoslit arrays. The breakdown of Ogston sieving was supplanted at higher electric fields to recover rapid separation with a reversed elution order and elution times one to two orders of magnitude faster than with Ogston sieving at lower fields. A simple kinetic model describes the experimental results.
In-plane magnetoresistance and magnetization reversal of cobalt antidot arrays
Authors: Meng T.-J. , Laloë J.-B. , Holmes S. N. , Husmann A. , Jones G. A. C.
Published: August 2009

Cobalt antidot arrays defined within a Hall bar mesa have been fabricated using electron-beam lithography. The diameter of the circular antidots was fixed at 1μm with the antidot edge-to-edge spacing varying from 2to0.5μm in a square lattice and 0.4μm in a rotated square lattice. In-plane magnetoresistance measurements were carried out to investigate the magnetization reversal properties. Antidots greatly modify the domain configuration and work as domain wall pinning sites. As a result, the switching and saturation fields increase while the magnetoresistance ratio decreases with the inclusion of antidots and also with increasing antidot areal density. Micromagnetic simulations show that the magnetization reversal of antidot arrays proceeds with the formation and annihilation of domain walls, which is manifested as Barkhausen jumps in the transition regions of the magnetoresistance curves.
Analysis of the magnetic coupling in binuclear systems. III. The role of the ligand to metal charge transfer excitations revisited
Authors: Calzado Carmen J. , Angeli Celestino , Taratiel David , Caballol Rosa , Malrieu Jean-Paul
Published: August 2009

In magnetic coordination compounds and solids the magnetic orbitals are essentially located on metallic centers but present some delocalization tails on adjacent ligands. Mean field variational calculations optimize this mixing and validate a single band modelization of the intersite magnetic exchange. In this approach, due to the Brillouin’s theorem, the ligand to metal charge transfer (LMCT) excitations play a minor role. On the other hand the extensive configuration interaction calculations show that the determinants obtained by a single excitation on the top of the LMCT configurations bring an important antiferromagnetic contribution to the magnetic coupling. Perturbative and truncated variational calculations show that contrary to the interpretation given in a previous article [C. J. Calzado et al., J. Chem. Phys. 116, 2728 (2002)] the contribution of these determinants to the magnetic coupling constant is not a second-order one. An analytic development enables one to establish that they contribute at higher order as a correlation induced increase in the LMCT components of the wave function, i.e., of the mixing between the ligand and the magnetic orbitals. This larger delocalization of the magnetic orbitals results in an increase in both the ferro- and antiferromagnetic contributions to the coupling constant.
Instability pathways of hydrogel microlenses under concentrated loadings
Authors: Zhang X. X. , Zeng K. Y. , Li J. , Zhang Y. W.
Published: August 2009

We investigate the mechanical instabilities of hydrogel microlenses triggered by concentrated loadings. Depending on hydrogel microlenses, geometries, and loading conditions, a series of nontrivial instability pathways is observed, including transitions of localized polyhedral faceted shapes with multifold vertices created by bifurcation, snapping through curvature inversion and large load drop, and wrinkling driven by combined in-plane stretching and compression. These pathways reveal the richness of the mechanical behavior of hydrogel microlenses and provide potential strategies to control the design and shape of complex hydrogel microlenses.
Influence of thermal strains on the electrocaloric and dielectric properties of ferroelectric nanoshells
Authors: Dai Xiao , Cao Hai-Xia , Jiang Qing , Lo Veng Cheong
Published: August 2009

The electrocaloric effect and dielectric tunability of BaTiO3 ferroelectric nanoshells on Si and MgO cores are investigated using the modified Landau–Ginzburg–Devonshire theory, in which the surface tension and thermal strain are taken into account. The numerical results exhibit a peak of electrocaloric coefficient near the critical nanoshell thickness accompanied with the size-driven phase transition. In addition to the enhanced adiabatic temperature difference, the compressive thermal strain also significantly improves the dielectric tunability. More importantly, the ferroelectric nanoshell displays pronounced electrocaloric effect: ΔT(Tm)=2.09 K for the nanoshell on Si core and ΔT(Tm)=2.33 K on MgO core, respectively. Essentially, the ferroelectric nanoshell provides an effective means to acquire good electrocaloric effect and high dielectric tunability by adjusting the wall thickness, core radius, annealing temperature, and various core materials, which may effectively contribute to the stress level in the ferroelectric nanoshell.
Shape effects on the yield stress and deformation of silicon nanowires: A molecular dynamics simulation
Authors: Yang Zhenyu , Lu Zixing , Zhao Ya-Pu
Published: August 2009

The tension and compression of single-crystalline silicon nanowires (SiNWs) with different cross-sectional shapes are studied systematically using molecular dynamics simulation. The shape effects on the yield stresses are characterized. For the same surface to volume ratio, the circular cross-sectional SiNWs are stronger than the square cross-sectional ones under tensile loading, but reverse happens in compressive loading. With the atoms colored by least-squares atomic local shear strain, the deformation processes reveal that the failure modes of incipient yielding are dependent on the loading directions. The SiNWs under tensile loading slip in {111} surfaces, while the compressive loading leads the SiNWs to slip in the {110} surfaces. The present results are expected to contribute to the design of the silicon devices in nanosystems.
First-principles study of structural, thermodynamic, elastic, and magnetic properties of Cr2GeC under pressure and temperature
Authors: Zhou Wei , Liu Lijuan , Wu Ping
Published: August 2009

The dependences of the structural, thermodynamic, elastic, and magnetic properties of Cr2GeC on pressure and temperature were investigated with the quasiharmonic Debye model and the first-principles method based on the density functional theory. Our calculated data, which were obtained at different pressures and temperatures, are in good agreement with the experimental results. Cr2GeC is mechanically stable in the pressure range of 0–50 GPa and the compressibility along the a axis is greater than along the c axis indicating that the presence of C in the interstitial sites of the Cr octahedra can enhance the stability of the Cr–Ge bonds. It is also found that the antiferromagnetic state is the ground state of Cr2GeC and the total induced magnetic moment of the metastable ferromagnetic state decreases with pressure and completely vanishes at about 25 GPa.
The experimental realization of a two-dimensional colloidal model system
Authors: Ebert F. , Dillmann P. , Maret G. , Keim P.
Published: August 2009

We present the technical details of an experimental method to realize a model system for two-dimensional (2D) phase transitions and the glass transition. The system consists of several hundred thousand colloidal superparamagnetic particles confined by gravity at a flat water-air interface of a pending water droplet where they are subjected to Brownian motion. The dipolar pair potential and, therefore, the system temperature are not only known precisely but also directly and instantaneously controllable via an external magnetic field H. In the case of a one-component system of monodisperse particles the system can crystallize upon application of H whereas in a two component system it undergoes a glass transition. Up to 10 000 particles are observed by video microscopy and image processing provides their trajectories on all relative length and time scales. The position of the interface is actively regulated thereby reducing surface fluctuations to less than 1 μm and the setup inclination is controlled to an accuracy of ±1 μrad. The sample quality being necessary to enable the experimental investigation of the 2D melting scenario, 2D crystallization, and the 2D glass transition, is discussed.
A rigorous framework for multiscale simulation of stochastic cellular networks
Authors: Chevalier Michael W. , El-Samad Hana
Published: August 2009

Noise and stochasticity are fundamental to biology and derive from the very nature of biochemical reactions where thermal motion of molecules translates into randomness in the sequence and timing of reactions. This randomness leads to cell-cell variability even in clonal populations. Stochastic biochemical networks are modeled as continuous time discrete state Markov processes whose probability density functions evolve according to a chemical master equation (CME). The CME is not solvable but for the simplest cases, and one has to resort to kinetic Monte Carlo techniques to simulate the stochastic trajectories of the biochemical network under study. A commonly used such algorithm is the stochastic simulation algorithm (SSA). Because it tracks every biochemical reaction that occurs in a given system, the SSA presents computational difficulties especially when there is a vast disparity in the timescales of the reactions or in the number of molecules involved in these reactions. This is common in cellular networks, and many approximation algorithms have evolved to alleviate the computational burdens of the SSA. Here, we present a rigorously derived modified CME framework based on the partition of a biochemically reacting system into restricted and unrestricted reactions. Although this modified CME decomposition is as analytically difficult as the original CME, it can be naturally used to generate a hierarchy of approximations at different levels of accuracy. Most importantly, some previously derived algorithms are demonstrated to be limiting cases of our formulation. We apply our methods to biologically relevant test systems to demonstrate their accuracy and efficiency.
Linear and saturated characteristics of a coaxial-waveguide gyrotron backward-wave oscillator
Authors: Hung C. L.
Published: August 2009

A coaxial waveguide interaction structure may be suitable for a gyrotron backward-wave oscillator (gyro-BWO) operating in millimeter and submillimeter waves with good mode selectivity, frequency tunability, and high power. This study analyzes the linear and nonlinear behaviors of a coaxial-waveguide gyro-BWO by using a single-mode, self-consistent nonlinear code. Simulation results indicate that the coaxial gyro-BWO exhibits features similar to those of a cylindrical-waveguide gyro-BWO, such as nonlinear field contraction, the relation of start-oscillation current to interaction length, and the difference value of the transit angle between adjacent axial modes. Additionally, the coaxial gyro-BWO has distinctive characteristics due to its transverse geometrical parameter C, i.e., the ratio of the outer radius to the inner radius. The beam-wave coupling strength of the coaxial gyro-BWO is a function of parameter C. As a result, the start-oscillation current of the coaxial gyro-BWO varies as the C value selected varies. The coaxial gyro-BWOs with different C values require different interaction lengths to reach the saturated state for the same beam current. Parameter C also impacts the magnetic tuning bandwidth of the coaxial gyro-BWO. However, maximum efficiency at saturation, which was obtained by tuning the magnetic field, is not highly dependent on the value of parameter C.
Enhanced Raman scattering by spatially distributed atomic coherence
Authors: Chen L. Q. , Zhang Guo-Wan , Yuan Chun-Hua , Jing Jietai , Ou Z. Y. , Zhang Weiping
Published: August 2009

We demonstrate experimentally an enhancement in Raman scattering in Rb atomic vapor due to the atomic coherence initially prepared by a weak write laser. We find that the enhanced Raman scattering depends on the spatial distribution of the atomic spin coherence and can be explained with a simple picture of three-wave mixing. This effect can in principle be used to have a light conversion efficiency near unity in Raman process. Such an enhanced Raman scattering may have practical applications in quantum information, nonlinear optics, and laser spectroscopy.
Effect of bias stress on mechanically strained low temperature polycrystalline silicon thin film transistor on stainless steel substrate
Authors: Peng I-Hsuan , Liu Po-Tsun , Wu Tai-Bor
Published: August 2009

This paper reported the variation in performance of bias stressed low-temperature polycrystalline silicon thin film transistors (LTPS TFTs) fabricated on metal foil substrate for flexible display applications. The mobility, threshold voltage (Vth), and trap density (Nt) of the proposed p-channel poly-Si TFT as a function of curvature radii were investigated. The significant increase in Vth by 9% was observed as the compressive or tensile mechanical strain increases to 0.1%. In addition, the hole mobility increases by 7% due to an increased compressive strain of 0.1%, while hole mobility decreases by 3.5% with the increase in tensile strain of 0.1%. After dc bias stressing, the LTPS TFT with mechanical strain had better performance than that on flat state in both the mobility drop and Vth shift. Mechanical strain influences the lattice arrangement and electric field at the drain electrode region that resisted device degradation in early stressing period.
Anomalies in the thermomechanical behavior of Ba0.5Sr0.5Co0.8Fe0.2O3−δ ceramic oxygen conductive membranes at intermediate temperatures
Authors: Huang B. X. , Malzbender J. , Steinbrech R. W. , Grychtol P. , Schneider C. M. , Singheiser L.
Published: August 2009

The thermomechanical properties of Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) were measured using ring-on-ring tests and depth-sensitive microindentation. The cubic BSCF material exhibits an anomaly in mechanical properties between 200 and 400 °C. The observed anomaly is attributed to the transition of Co3+ spin states which is experimentally confirmed by susceptibility measurements. Furthermore, slip lines were observed around the impression when indentation tests were carried out above 260 °C.
Rapid laminating mixer using a contraction-expansion array microchannel
Authors: Lee Myung Gwon , Choi Sungyoung , Park Je-Kyun
Published: August 2009

Three-dimensional lamination mixing is demonstrated in a simple and easily fabricated contraction-expansion array microchannel. The abrupt change of the cross-sectional area of the channel curves fluid streams and accelerates the flow velocity especially at the entrance of the contraction region. Centrifugal effects at that region result in Dean vortices that continuously split and redirect fluid streams, thereby enabling appreciable mixing. The presented mixer provides a level of 90% mixing in the relatively large range of Reynolds number from 4.3 to 28.6 by employing the channel with 30 contraction-expansion units.
Tunability of the piezoelectric fields in strained III-V semiconductors
Authors: Garg R. , Hüe A. , Haxha V. , Migliorato M. A. , Hammerschmidt T. , Srivastava G. P.
Published: August 2009

In this work we show that tetragonal strain can be used to create a sign reversal of the piezoelectric field in InAs/GaAs semiconductor heterostructures. The strain dependence of the internal displacement of the cation-anion pairs and of the bond polarity are taken into account, beyond the linear model, within an ab initio scheme. The reported tunability of the piezoelectric field is a concept that can be exploited in optoelectronic devices.
Tunneling electroresistance in ferroelectric tunnel junctions with a composite barrier
Authors: Zhuravlev M. Ye. , Wang Y. , Maekawa S. , Tsymbal E. Y.
Published: August 2009

Tunneling electroresistance (TER) effect is the change in the electrical resistance of a ferroelectric tunnel junction (FTJ) associated with polarization reversal in the ferroelectric barrier layer. Here we predict that a FTJ with a composite barrier that combines a functional ferroelectric film and a thin layer of a nonpolar dielectric can exhibit a significantly enhanced TER. Due to the change in the electrostatic potential with polarization reversal, the nonpolar dielectric barrier acts as a switch that changes its barrier height from a low to high value. The predicted values of TER are giant and indicate that the resistance of the FTJ can be changed by several orders in magnitude at the coercive electric field of ferroelectric.
Degradation of oxide-passivated boron-diffused silicon
Authors: Thomson Andrew F. , McIntosh Keith R.
Published: August 2009

Recombination in oxide-passivated boron-diffused silicon is found to increase severely at room temperature. The degradation reaction leads to a 45 fold increase in emitter recombination that saturates in ∼120 days, irrespective of whether the samples received a forming-gas anneal. The degradation was also examined for diffusions stored at 50, 75, and 100 °C. The results indicate that the degradation follows a second-order reaction where the time constant of one component of the reaction is 10–40 times shorter than the other, and where the activation energy of the fast reaction is 0.19±0.05 eV. Subsequent to degradation, annealing in air reduces the recombination with increasing anneal temperature saturating at ∼300 °C to a value that is about four times higher than the predegradation value. A likely cause of this degradation is a reaction of atomic hydrogen at the silicon-oxide-silicon interface.
Uniquely Scottish? Placing Scottish Devolution in Theoretical Perspective
Authors: Tijmstra Sylvia A R
Published: August 2009

This existing literature on the Scottish devolution process tends to stress the unique aspects of the case. I make a contribution to this literature by placing the insights that have emerged in case-study research within the context of more general theorising. Combining concepts found in the literature on political legitimacy with intuitions derived from veto player theory, I provide a structured and theoretically grounded framework of devolution decisions and nondecisions. This approach helps to place the process that eventually led to the creation of a Scottish Parliament in a wider context.