bluuebunny/crossref_metadata_2025 huggingface dataset:
Multidimensional solid‐state NMR studies of the structure and dynamics of pectic polysaccharides in uniformly 13C‐labeled Arabidopsis primary cell walls
Authors: Pérez García Marilú , Wang Tuo , Salazar Andre , Zabotina Olga A. , Hong Mei
Published: July 2012

Plant cell wall (CW) polysaccharides are responsible for the mechanical strength and growth of plant cells; however, the high‐resolution structure and dynamics of the CW polysaccharides are still poorly understood because of the insoluble nature of these molecules. Here, we use 2D and 3D magic‐angle‐spinning (MAS) solid‐state NMR (SSNMR) to investigate the structural role of pectins in the plant CW. Intact and partially depectinated primary CWs of Arabidopsis thaliana were uniformly labeled with 13C and their NMR spectra were compared. Recent 13C resonance assignment of the major polysaccharides in Arabidopsis thaliana CWs allowed us to determine the effects of depectination on the intermolecular packing and dynamics of the remaining wall polysaccharides. 2D and 3D correlation spectra show the suppression of pectin signals, confirming partial pectin removal by chelating agents and sodium carbonate. Importantly, higher cross peaks are observed in 2D and 3D 13C spectra of the depectinated CW, suggesting higher rigidity and denser packing of the remaining wall polysaccharides compared with the intact CW. 13C spin–lattice relaxation times and 1H rotating‐frame spin–lattice relaxation times indicate that the polysaccharides are more rigid on both the nanosecond and microsecond timescales in the depectinated CW. Taken together, these results indicate that pectic polysaccharides are highly dynamic and endow the polysaccharide network of the primary CW with mobility and flexibility, which may be important for pectin functions. This study demonstrates the capability of multidimensional SSNMR to determine the intermolecular interactions and dynamic structures of complex plant materials under near‐native conditions. Copyright © 2012 John Wiley & Sons, Ltd.
Physiotherapy Provision Following Discharge after Total Hip and Total Knee Replacement: A Survey of Current Practice at High‐Volume NHS Hospitals in England and Wales
Authors: Artz Neil , Dixon Sam , Wylde Vikki , Beswick Andrew , Blom Ashley , Gooberman‐Hill Rachael
Published: July 2012

Background

Total hip replacement (THR) and total knee replacement (TKR) are two common elective orthopaedic procedures, and the provision of physiotherapy for patients after discharge is variable, with evidence for best practice remaining uncertain.

Aims and objectives

To determine the standard physiotherapy service offered to patients following discharge after THR and TKR.

Methods

A telephone survey was carried with clinicians at 24 high‐volume NHS orthopaedic centres in England and Wales. Information was gathered on standard physiotherapy provision and categorized into; no routine physiotherapy, outpatient physiotherapy (including one‐to‐one and group), home‐based physiotherapy or other physiotherapy (including telephone consultation and drop‐in services).

Results

No centres surveyed referred patients to outpatient physiotherapy as a routine pathway of care following THR. Eleven centres provided group physiotherapy to patients after discharge following TKR compared with five centres providing one‐to‐one outpatient physiotherapy.

Conclusion

The provision of physiotherapy following discharge after TKR is a more common practice than after THR, where ongoing physiotherapy is provided depending upon clinical need. Group exercises are the favoured destination for patients following TKR in high‐volume centres. Copyright © 2012 John Wiley & Sons, Ltd.
Straightforward preparation of polymers based on oligodimethylsiloxane and alkylamine
Authors: Leymarie Ludovic , Dupuy Jérôme , Villegas Estelle , Chaumont Philippe , Sintes‐Zydowicz Nathalie , Fleury Etienne
Published: July 2012

Novel oligodimethylsiloxane‐based polymers with alkyl side chain were synthesized in bulk by step‐growth polymerization between α,ω‐glycidyl ether oligodimethylsiloxanes and a monoalkylamine in the absence of catalyst and at temperatures ranging between 80 and 180 °C. Matrix assisted laser desorption ionization time of flight results attested for the high reactivity of the amine functions with the glycidyl groups and revealed that the main polymer structure was (A2B2)n type with alkyl moieties as dangling chains. No etherification was observed during the reaction even at high temperatures and the nature of the end groups strongly depended on the molar ratio between glycidyl and amine functions. Polymerization reactions were followed by 1H NMR and the kinetics of the glycidyl‐amine reaction pointed out the dependence of temperature, molar ratio, and the molar mass of the oligodimethylsiloxane. High conversion rates were obtained, especially with the lowest molecular weight oligodimethylsiloxane. An optimized kinetic model derived from the Horie's model was discussed and permitted to correctly fit the experimental data. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Oxidative coupling polymerization of bishydrazide for the synthesis of poly(diacylhydrazine): Oxidative preparation of oxidatively degradable polymer
Authors: Nagashima Kentaro , Kihara Nobuhiro , Iino Yusuke
Published: July 2012

The oxidative coupling polymerization of bishydrazide is successfully performed to form poly(diacylhydrazine) (PDAH), which is an oxidatively degradable polymer. Oxone is an effective oxidant, and a mixture of an aprotic polar solvent, water, and acetonitrile or N,N‐dimethylacetamide is necessary as the solvent. On treatment of PDAH with sodium hypochlorite solution or hydrogen peroxide, the PDAH is rapidly oxidized and degraded to the corresponding dicarboxylic acid. When hydrogen peroxide is used as the oxidant, the addition of acetonitrile and potassium carbonate is necessary for effective degradation. PDAH exhibits high thermal stability in air and a high Tg value. No oxidation is observed in air. Thus, PDAH is an oxidatively degradable high‐performance polymer that is stable toward oxygen. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Synthesis of mikto‐topology star polymer containing one cyclic arm
Authors: Jiang Xiubo , Shi Yi , Zhu Wen , Chen Yongming , Xi Fu
Published: July 2012

Well‐defined mikto‐topology star polystyrene composed of one cyclic arm and four linear arms was synthesized by a combination of atom transfer radical polymerization (ATRP) and Cu‐catalyzed azide‐alkyne cycloaddition (CuAAC) click reaction. First, the bromine‐alkyne α,ω‐linear polystyrenes containing four hydroxyl groups protected with acetone‐based ketal groups were synthesized by ATRP of styrene using a designed initiator. Then, the bromine end‐group was converted to the azide and the linear polystyrene was cyclized intra‐molecularly by the CuAAC reaction. The four hydroxyl groups were released by deprotection and then esterified with 2‐bromoisobutyryl bromide to produce a cyclic polymer bearing four ATRP initiating units. By subsequent ATRP of styrene to grow linear polymers with the cyclic polystyrene as a macroinitiator, the mikto‐topology star polymers were prepared. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Volunteer Orthopedic Surgical Trips in Nicaragua: A Cost‐effectiveness Evaluation
Authors: Chen Andrew T. , Pedtke Andrew , Kobs Jeffrey K. , Edwards George S. , Coughlin R. Richard , Gosselin Richard A.
Published: July 2012

Background

Injuries account for a substantial portion of the world’s burden of disease and require effective surgical care. Volunteer surgical teams that form partnerships with hospitals help build local surgical capacity while providing immediate care. The purpose of the present study was to evaluate the cost‐effectiveness of short orthopedic surgical volunteer trips as a method of reducing the global burden of surgical disease through both surgical and educational interventions.

Methods

Data were collected from a scheduled volunteer trip to Leon, Nicaragua, in January 2011 as part of the Cooperación Ortopédica Americano Nicaraguense (COAN), a 501c3 nonprofit organization established in 2002. Costs are from the COAN provider prospective with an additional analysis to include the Nicaraguan provider variable costs. The total burden of musculoskeletal disease averted from the patients receiving surgical intervention was derived using the disability‐adjusted‐life‐years (DALYs) framework and disability weights from the disease control priority project. The cost‐effectiveness ratio was calculated by dividing the total costs by the total DALYs averted.

Results

A total of 44.78 DALYs were averted in this study, amounting to an average of 1.49 DALYs averted per patient. The average cost per patient from the COAN provider perspective was $525.64, and from both the COAN and Nicaraguan provider perspective it was $710.97. In the base case, cost‐effectiveness was $352.15 per DALY averted, which is below twice the Nicaraguan per capita gross national income ($652.40).

Conclusions

Volunteer orthopedic surgical trips are cost‐effective in Nicaragua. Further research should be conducted with multiple trips and with different patient populations to test the generalizability of the results.
Development of a Formula to Predict Parathyroid Carcinoma in Patients with Primary Hyperparathyroidism
Authors: Karakas Elias , Müller Hans‐Helge , Lyadov Vladimir K. , Luz Stephanie , Schneider Ralph , Rothmund Matthias , Bartsch Detlef K. , Schlosser Katja
Published: July 2012

Background

Cure of parathyroid carcinoma (PC) requires initial en bloc resection, including resection of all tumor‐bearing tissue, with hemithyroidectomy and dissection of the central lymph node compartment. Unfortunately, no reliable preoperative criteria have yet been assessed to indicate a high likelihood of PC. Thus, the aim of the present study was to develop a formula to indicate preoperatively the presence of PC.

Methods

A prospective database of 1,363 patients with primary hyperparathyroidism (pHPT) was screened for patients with PC. Age, gender, surgical procedures, laboratory data, and follow‐up results were evaluated and compared to a group of patients with benign pHPT. Based on preoperative serum calcium (Ca) and parathyroid hormone (PTH) levels, as well as patients’ age at the time of diagnosis, a formula was developed by a multivariate logistic model that estimates the individual risk for PC.

Results

Between 1987 and 2008, 19 patients with PC were identified. Ca (3.8 ± 0.3 vs 2.9 ± 0.3 mmo/l; p = 0.0002) and PTH levels (1,250 ± 769 vs 194 ± 204 pg/ml; p = 0.0030) were significantly higher in patients with PC than in those with benign pHPT. Patients with PC were also significantly younger than patients with benign pHPT (48.9 ± 12.1 vs 59.1 ± 13.8 years; p < 0.05). With a ≥5 % probability that a given patient suffered from PC, the sensitivity and specificity to identify the disease were 100 and 30 %, respectively, with the new Ca, PTH, and age based logarithmic formula.

Conclusions

The new logarithmic formula can be used to calculate the individual risk for PC. If the calculated individual risk exceeds 5 %, en bloc resection seems to be justified to provide long‐term cure in case of PC.
Ingestion of low‐dose ibuprofen following resistance exercise in postmenopausal women
Authors: Candow Darren G. , Chilibeck Philip D. , Weisgarber Krissy , Vogt Emelie , Baxter-Jones Adam D. G.
Published: July 2012

Background

Postmenopausal women typically experience accelerated muscle loss which has a negative effect on strength. The maximum daily recommended dosage of ibuprofen (1,200 mg) following resistance exercise has been shown to increase muscle hypertrophy and strength in older adults. This study aimed to determine the effects of low‐dose ibuprofen (400 mg) immediately following resistance exercise sessions on muscle mass and strength in postmenopausal women.

Methods

Participants were randomized to ingest ibuprofen (IBU: n = 15, 57.8 ± 5.1 years, 75.9 ± 9.0 kg, 165.9 ± 6.2 cm, BMI = 28 ± 4 kg/m2) or placebo (PLA: n = 13, 56.5 ± 4.4 years, 73.0 ± 10.4 kg, 163.1 ± 5.9 cm, BMI = 26 ± 9 kg/m2) immediately following resistance exercise (11 whole‐body exercises), which was performed 3 days/week, on nonconsecutive days, for 9 weeks. Prior to and following training, measures were taken for lean tissue mass (dual‐energy X‐ray absorptiometry), muscle size of the elbow and knee flexors and extensors and ankle dorsiflexors and plantar flexors (ultrasound), and strength (one‐repetition maximum leg press and chest press).

Results

Over the 9 weeks of training, there were significant changes (p < 0.05) in lean tissue mass (IBU, −1.1 ± 1.0 kg; PLA, −0.7 ± 1.4 kg), muscle size of the knee extensors (IBU, 0.3 ± 0.6 cm; PLA, 0.2 ± 0.7 cm), ankle dorsiflexors (IBU, 0.5 ± 0.8 cm; PLA, 0.1 ± 0.5 cm), and ankle plantar flexors (IBU, 0.3 ± 0.9 cm; PLA, 0.5 ± 0.9 cm), leg press strength (IBU, 20.6 ± 18.0 kg; PLA, 20.0 ± 20.0 kg), and chest press strength (IBU, 5.1 ± 9.5 kg; PLA, 8.1 ± 7.6 kg), with no differences between groups.

Conclusion

Low‐dose ibuprofen following resistance exercise has no greater effect on muscle mass or strength over exercise alone in postmenopausal women.
Flora Australiensis
Authors: Bentham George , Mueller Ferdinand von
Published: July 2012

George Bentham (1800–84) was one of Britain's most influential botanists, whose own collection of plant specimens numbered more than 100,000. Although he donated his herbarium to the Royal Botanic Gardens, Kew in 1854, he continued to make significant contributions to the field, including this exhaustive, seven-volume work detailing the plant life of Australia, which was published from 1863 to 1878. It was part of a series of works commissioned by the British government to document the flora in its colonies. Using the extensive numbers of specimens at Kew - and with the help of Ferdinand Mueller (1825–96), a German botanist in Australia - Bentham was able to compile descriptions of more than 8,000 species of Australian plants, making these volumes the first completed compendium of the flora of any large continental area. Volume 2, published in 1864, gives descriptions of seven orders of the dicotyledon class of flowering plant.
The Right to Reparation in International Law for Victims of Armed Conflict
Authors: Evans Christine
Published: July 2012

In this evaluation of the international legal standing of the right to reparation and its practical implementation at the national level, Christine Evans outlines State responsibility and examines the jurisprudence of the International Court of Justice, the Articles on State Responsibility of the International Law Commission and the convergence of norms in different branches of international law, notably human rights law, humanitarian law and international criminal law. Case studies of countries in which the United Nations has played a significant role in peace negotiations and post-conflict processes allow her to analyse to what extent transitional justice measures have promoted State responsibility for reparations, interacted with human rights mechanisms and prompted subsequent elaboration of domestic legislation and reparations policies. In conclusion, she argues for an emerging customary right for individuals to receive reparations for serious violations of human rights and a corresponding responsibility of States.
Shunt reduction to pulmonary arteriovenous malformations using a modified covered stent
Authors: Argueta-Morales I. Ricardo , Hathaway Robyn M. , Nykanen David G.
Published: July 2012

Pulmonary arteriovenous malformations in patients with congenital heart disease have been associated with interruption of hepatic venous return to the lungs. We report a novel technique to improve systemic saturation using a modified covered stent in a patient with unilateral left pulmonary arteriovenous malformations in the setting of a Fontan circulation.
Solar wind interactions with the dusty magnetosphere of Jupiter produce shocks and solitons associated with nonlinear drift waves
Authors: Saleem H. , Moslem W. M. , Shukla P. K.
Published: July 2012

It is pointed out that interactions between the solar wind and the dusty magnetospheres of planets and comets give rise to nonlinear electrostatic drift waves. It is assumed that after transient processes a local steady state is attained with the same sheared flow of electrons and ions Vi0(x) = Ve0(x) = V0(x)
along the initial constant component of B0z of the total sheared magnetic field
. The nonlinear perturbation caused by the electron temperature gradient forms solitary and shock structures, depending upon the dominant role of either the wave dispersion or dissipation, respectively. The theoretical model has been applied to the magnetosphere of Jupiter that contains positively charged dust grains. This investigation predicts the formation of short scale electrostatic solitons having width of the order of 1 m and shocks having widths of the order of 2 m.
Dominant modes of Diurnal Temperature Range variability over Europe and their relationships with large‐scale atmospheric circulation and sea surface temperature anomaly patterns
Authors: Ionita M. , Lohmann G. , Rimbu N. , Scholz P.
Published: July 2012

The relationships between the dominant modes of interannual variability of Diurnal Temperature Range (DTR) over Europe and large‐scale atmospheric circulation and sea surface temperature anomaly fields are investigated through statistical analysis of observed and reanalysis data. It is shown that the dominant DTR modes as well as their relationship with large‐scale atmospheric circulation and sea surface temperature anomaly fields are specific for each season. During winter the first and second modes of interannual DTR variability are strongly related with the North Atlantic Oscillation and the Scandinavian pattern, while the third mode is related with the Atlantic Multidecadal Oscillation. Strong influence of the Atlantic Multidecadal Oscillation and the Arctic Oscillation on spring DTR modes of variability was also detected. During summer the DTR variability is influenced mostly by a blocking‐like pattern over Europe, while the autumn DTR variability is associated with a wave train like pattern, which develops over the Atlantic Ocean and extends up to Siberia. It is also found that the response of DTR to global sea surface temperature is much weaker in spring and summer comparing to winter and autumn. A correlation analysis reveals a strong relationship between DTR modes of variability and the Cloud Cover anomalies during all seasons. The influence of the potential evapotranspiration and precipitation anomalies on DTR modes of variability is strongest during summer, but it is significant also in spring and autumn. It is suggested that a large part of interannual to decadal DTR variability over Europe is induced by the large‐scale climate anomaly patterns via modulation of cloud cover, precipitation and potential evapotranspiration anomaly fields.
Modeling large scale shoreline sand waves under oblique wave incidence
Authors: van den Berg N. , Falqués A. , Ribas F.
Published: July 2012

The hypothesis that the formation and dynamics of large scale shoreline sand waves can be explained by a feedback mechanism between waves and nearshore morphology under very oblique wave incidence is explored with a quasi 2D nonlinear morphodynamic model. Using constant wave conditions it is found that if the wave incidence angle at the depth of closure is larger than about 45° the rectilinear coastline becomes unstable and a shoreline sand wavefield develops from small random perturbations. Shoreline sand waves develop with wavelengths between 2 and 5 km, they migrate downdrift at about 0.5 km/yr and they reach amplitudes up to 120 m within 13 years. Larger wave obliquity, higher waves and shorter wave periods strengthen the shoreline instability. Cross‐shore transport is essential for the instability and faster cross‐shore dynamics leads to a faster growth of the sand waves. Simulations with variable wave incidence angles (alternating between 60° and 30°) show that a large proportion of high angle waves is required for spontaneous sand wave formation (at least 80%). Insight is provided into the physical mechanism behind high angle wave instability and the occurrence of a optimal length scale for sand wave growth. The generic model results are consistent with existing observations of shoreline sand waves, in particular with those along the southwest coast of Africa.
Elevated methane concentrations in trees of an upland forest
Authors: Covey Kristofer R. , Wood Stephen A. , Warren Robert J. , Lee Xuhui , Bradford Mark A.
Published: July 2012

There is intense debate about whether terrestrial vegetation contributes substantially to global methane emissions. Although trees may act as a conduit for methane release from soils to atmosphere, the debate centers on whether vegetation directly produces methane by an uncharacterized, abiotic mechanism. A second mechanism of direct methane production in plants occurs when methanogens – microorganisms in the domain Archaea – colonize the wood of living trees. In the debate this biotic mechanism has largely been ignored, yet conditions that promote anaerobic activity in living wood, and hence potentially methane production, are prevalent across forests. We find average, growing season, trunk‐gas methane concentrations >15,000μL·L−1in common, temperate‐forest species. In upland habitat (where soils are not a significant methane source), concentrations are 2.3‐times greater than in lowland areas, and wood cores produce methane in anaerobic, lab‐assays. Emission rate estimates from our upland site are 52 ± 9.5 ng CH4 m−2 s−1; rates that are of a similar magnitude to the soil methane sink in temperate forest, and equivalent in global warming potential to ∼18% of the carbon likely sequestered by this forest. Microbial infection of one of the largest, biogenic sinks for carbon dioxide, living trees, might result in substantial, biogenic production of methane.
Segmentation and Representation of Consonant Blends in Kindergarten Children’s Spellings
Authors: Werfel Krystal L. , Schuele C. Melanie
Published: July 2012

Purpose

The purpose of this study was to describe the growth of children’s segmentation and representation of consonant blends in the kindergarten year and to evaluate the extent to which linguistic features influence segmentation and representation of consonant blends. Specifically, the roles of word position (initial blends, final blends), class of blends, homorganicity, and nasality were considered.

Method

Forty kindergarten children completed a developmental spelling measure (26 words with initial or final blends) 3 times at 6-week intervals. Responses were analyzed for logical representation of speech sounds to describe developmental change and differential accuracy of segmentation and representation across blend types.

Results

Kindergarten children showed varied ability to segment and represent consonant blends and were differentially successful depending on the linguistic features of the blends. Children were more likely to represent initial blends than final blends, final nonnasal blends than final nasal blends, nonhomorganic blends than homorganic blends, and initial nasal blends than final nasal blends.

Conclusion

During the period of emergence, the properties of phonemes that comprise consonant blends influence children’s ability to segment and represent blends. This finding has implications for how phonemic awareness and spelling instruction and intervention might proceed.
Syllable-Timed Speech Treatment for School-Age Children Who Stutter: A Phase I Trial
Authors: Andrews Cheryl , O’Brian Sue , Harrison Elisabeth , Onslow Mark , Packman Ann , Menzies Ross
Published: July 2012

Purpose

This clinical trial determined the outcomes of a simple syllable-timed speech (STS) treatment for school-age children who stutter.

Method

Participants were 10 children, ages 6–11 years, who stutter. Treatment involved training the children and their parents to use STS at near normal speech rates. The technique was practiced in the clinic and at home with the parents during everyday conversations.

Results

Nine months after commencing treatment, stuttering had decreased by >50% for half of the children, with 2 children attaining 81% and 87% reduction. Intention-to-treat analysis showed a clinically and statistically significant reduction in stuttering for the group even when a withdrawn participant was included. These results were mostly confirmed by self-reported stuttering severity ratings and were supported by improved situation avoidance and quality-of-life scores. There was considerable individual variation in response to the treatment.

Conclusion

STS shows promise as a treatment for some school-age children who stutter. As a fluency technique, it is simple to learn and simple to teach, and the children in this study appeared to enjoy the treatment. The efficacy of the treatment could likely be improved with modifications.
Efficacy of Auditory Interventions for Central Auditory Processing Disorder: A Response to Fey et al. (2011)
Authors: Bellis Teri James , Chermak Gail D. , Weihing Jeffrey , Musiek Frank E.
Published: July 2012

Purpose

To provide a commentary on “Auditory Processing Disorder and Auditory/Language Interventions: An Evidence-Based Systematic Review” by Fey et al. (2011).

Method

Examination of the conclusions drawn by Fey et al. (2011) in the context of the American Academy of Audiology (2010a, 2010b) and American Speech-Language-Hearing Association (2005a, 2005b, 2005c) guidelines for the diagnosis and treatment of auditory processing disorder, the evidence cited therein, and other pertinent published reports.

Results

The review provided by Fey et al. (2011) is limited due to the exclusion of pertinent efficacy studies from their analysis, inclusion of studies that did not employ strictly auditory-based therapies, and lack of well-defined experimental groups in many of the studies cited. Further, the questions posed by their literature review may not have addressed the efficacy of true auditory interventions in the remediation of auditory difficulties in children who have primary deficits in central auditory processing.

Conclusion

A more comprehensive review than that done by Fey et al. (2011) would have better addressed the fundamental question of the efficacy of direct remediation activities for children with central auditory processing disorder.
Managing Stuttering Beyond the Preschool Years
Authors: Nippold Marilyn A. , Packman Ann
Published: July 2012

Purpose

This prologue serves to introduce a research forum composed of studies that address the topic of stuttering in school-age children and adolescents. Researchers are encouraged to continue to build the knowledge base that sustains evidence-based practice in this area.

Method

The nature of stuttering as it evolves from early childhood into the school years is briefly described. Beyond the preschool years, children are unlikely to spontaneously recover from stuttering, and they often go on to suffer negative consequences, academically and socially, because of their disorder. If they are to overcome or manage their stuttering successfully, school-age children and adolescents require high-quality treatment. Three data-based studies that address the topic of stuttering in school-age children or adolescents are described, the ongoing need for empirical evidence regarding the management of stuttering is emphasized, and several issues relevant to future studies in this area are discussed.

Conclusion

Progress has occurred in the management of stuttering in school-age children and adolescents. Nevertheless, important questions remain unanswered concerning the most effective techniques and strategies to use in helping students who stutter achieve more fluent and natural-sounding speech in their quest to become more confident and effective communicators.
A Review of Literature on Ameloblastoma in Children and Adolescents and a Rare Case Report of Ameloblastoma in a 3-Year-Old Child
Authors: Chaudhary Zainab , Krishnan Sriram , Sharma Pankaj , Sharma Rakesh , Kumar Priya
Published: July 2012

A rare case report of a plexiform unicystic ameloblastoma in a 3-year-old girl stimulated us to conduct a review of literature to understand the correlation of this tumor with various factors such as that of age, sex, histopathological correlation, and its incidence rates pertaining to children and adolescent population. This is a case report of ameloblastoma in a 3-year-old patient, along with a literature review of ameloblastoma in relation to age. A computerized literature search using Medline was conducted for published articles on treatment of ameloblastoma. MeSH phrases used in search were ameloblastoma AND age; ameloblastoma AND children. The search was restricted to published articles from 1970 to 2010, as the histological features were not clearly defined until 1st edition of WHO histological classification of odontogenic tumors of 1971, search parameter was also set to select literatures under English language only. An additional systematic hand search was also conducted simultaneously to identify other published articles, considering similar parameters as used for Medline search. Most of search result yielded literatures in which primary importance were given to treatment patterns and prognosis of intervention, there were not much specific article or meta analysis which reviewed on the affected age range of ameloblastoma exclusively. We reviewed the identified literatures with patients’ age, case numbers, incidence, sex, location, and histopathology. The statistical data collected were exported to SPSS 16.0 for windows software which performed a descriptive analysis giving an average mean age of 14.1 years (range from 4 to 20); with maximum mean age being 16.0 and minimum mean age being 10.8 with standard deviation of 1.60. Majority of lesions 91.86% (327 of 356) were found between the age group of 11 and 20 years, only 8.14% (29 of 356) were below the age of 10 years. This rare case report highlights occurrence of plexiform unicystic ameloblastoma in maxilla of a 3-year-old girl, which is very much incongruent with the various review of literature on ameloblastoma in children and adolescents. We have emphasized the significance of patient's age and histopathological pattern of the tumor as it has its influence on the treatment plan. However, there is much of research needed with focus in respect to age, histological pattern, and treatment outcomes.
Pulsar in binary system may test fundamental theories
Authors: Rothenberg Marian S.
Published: July 2012

A pulsar in orbit about a second compact star would form a very convenient arrangement for studying gravitational interactions and learning the elusive details of the physics of neutron stars. So the announcement by Joseph Taylor and Russell Hulse of the University of Massachusetts, Amherst, that they have observed such a system has been greeted joyfully by general relativists and by astrophysicists who have been longing for a chance to test their models. Studying changes in the pulsar period as the rotating neutron star travels about its companion in a close, highly elliptical orbit should provide checks of time dilatation, precession and perihelion advance effects free of the complications that occur in the weaker gravitational fields of the solar system, perhaps settling the question of which theory of gravitation is the correct one. The changes in period may also yield more details of the structure of pulsars and perhaps even of the nature of the pulsed radiation.
Heavy-ion projectiles produce a new kind of fission
Authors: Levi Barbara G.
Published: July 2012

Nuclear scientists studying the reactions induced by heavy ions have encountered an unexpected process that has been variously dubbed “quasifission,” “deep inelastic transfer,” “relaxed-peak process,” “incomplete fusion” and “strongly damped collisions.” In this process the reaction products have the kinetic energies typical of fission products, but their masses differ from what one would expect in fission: In the latter process, each of the reaction products has a mass roughly equal to one-half of the total mass of the compound nucleus (target plus projectile). In quasifission the two product nuclei have masses close to those of the target and projectile, individually.
The past and future of American astronomy
Authors: Sagan Carl
Published: July 2012

The world has changed since 1899, but there are few fields that have changed more—in the development of fundamental insights and in the discovery of new phenomena—than astronomy. When we glance at the titles (see the box below) of some of the recent papers published, for example, in the Astrophysical Journal and Icarus, we can only conclude that our astronomical ancestors would have extracted a glimmer of meaning from them, but that the principal reaction would have been incredulity.
Origins of the American Astronomical Society
Authors: Berendzen Richard
Published: July 2012

During 1974 the American Astronomical Society is celebrating the 75th anniversary of its founding. To be precise historically, however, there are at least two problems with such a commemoration. First, when the association was founded in 1899, its name was not “The American Astronomical Society,” and second, another association with precisely that name had nominally been founded at least fifteen years earlier!
Stability of impurities with Coulomb potential in graphene with homogeneous magnetic field
Authors: Maier Thomas , Siedentop Heinz
Published: July 2012

Given a two-dimensional no-pair Weyl operator WZ with a point nucleus of charge Z, we show that a homogeneous magnetic field does not lower the critical charge beyond which it collapses.
Comparison of azimuthal ion velocity profiles using Mach probes, time delay estimation, and laser induced fluorescence in a linear plasma device
Authors: Thakur S. Chakraborty , McCarren D. , Lee T. , Fedorczak N. , Manz P. , Scime E. E. , Tynan G. R. , Xu M. , Yu J.
Published: July 2012

We compare measurements of radially sheared azimuthal plasma flow based on time delay estimation (TDE) between two spatially separated Langmuir probes, Mach probes and laser induced fluorescence (LIF). TDE measurements cannot distinguish between ion fluid velocities and phase velocities. TDE and Mach probes are perturbative, so we compare the results against LIF, a non-perturbative, spatially resolved diagnostic technique that provides direct measurements of the ion velocity distribution functions. The bulk ion flow is determined from the Doppler shift of the Argon absorption line at 668.6139 nm. We compare results from all the three diagnostics, at various magnetic fields, which acts as a control knob for development of drift wave turbulence. We find that while Mach probes and LIF give similar profiles, TDE measurements typically overestimate the velocities and are also sensitive to the drift wave modes being investigated.
Methods for fast evaluation of self-energy matrices in tight-binding modeling of electron transport systems
Authors: Huang Jun Z. , Cho Chew Weng , Wu Yumao , Jun Jiang Li
Published: July 2012

Simulation of quantum carrier transport in nanodevices with non-equilibrium Green’s function approach is computationally very challenging. One major part of the computational burden is the calculation of self-energy matrices. The calculation in tight-binding schemes usually requires dealing with matrices of the size of a unit cell in the leads. Since a unit cell always consists of several planes (for example, in silicon nanowire, four atomic planes for [100] crystal orientation and six for [111] and [112]), we show in this paper that a condensed Hamiltonian matrix can be constructed with reduced dimension (∼1/4 of the original size for [100] and ∼1/6 for [111] and [112] in the nearest neighbor interaction) and thus greatly speeding up the calculation. Examples of silicon nanowires with sp3d5s* basis set and the nearest neighbor interaction are given to show the accuracy and efficiency of the proposed methods.
Dynamic compression of cerium in the low-pressure γ − α region of the phase diagram
Authors: Jensen B. J. , Cherne F. J.
Published: July 2012

Plate impact experiments were performed to examine the dynamic response of cerium for loading paths that span the well known γ−α phase transition. The anomalous nature of the γ-phase and the large volume collapse at the γ−α boundary resulted in a ramp-wave followed by a shock jump for shock loading. This structured wave provided a convenient means for locating the phase boundary and determining the volume collapse at the transition. Experiments using a preheat capability were performed to obtain equation-of-state data, to locate and determine the volume compression along the phase boundary, and to determine the location of the critical point. Experimental results show that the ramp-wave peak increased with the initial sample temperature consistent with an increase in the transition stress while the magnitude of the shock jump decreased. The data were analyzed to determine the volume compression along the boundary pointing to a critical point at 1.648 ± 0.075 GPa. Additional experiments using a shock-release configuration were used to obtain data during release. All data were in good agreement with calculations from a multiphase equation-of-state that treats the γ and α phases as a binary alloy.
Eulerian indicators under continuously varying conditions
Authors: McIlhany Kevin L. , Wiggins Stephen
Published: July 2012

In this paper, we extend the notion of Eulerian indicators (EIs) for predicting Lagrangian mixing behavior previously developed for blinking flows to the continuous time setting. We apply the EIs to a study of mixing in a kinematic model of a time-dependent double-gyre with five different time dependencies—sinusoidal, sawtooth, square wave, triangular, and noise (which is constructed so that it is also periodic in time). Each of the five velocity fields is described by two parameters; the strength of the time dependence (ε) and the period (T). Based on a trajectory based quality of mixing diagnostic (Danckwerts’ normalized variance of concentration) we find that noisy time dependence has the largest region of good mixing in the parameter space and triangular time dependence has parameter values corresponding to the most complete and fastest mixing. These Lagrangian based predictions are confirmed by the EIs (product of the transversality and mobility). Although not every feature of the mixing behavior is captured by EIs, we show that they do in general predict the regions in the parameter space under consideration that correspond to good mixing. Moreover, the EIs offer a factor of 100 computational advantage in exploring the parameter space in comparison with the trajectory based mixing diagnostic.
An improvement in quantum mechanical description of solute-solvent interactions in condensed systems via the number-adaptive multiscale quantum mechanical/molecular mechanical-molecular dynamics method: Application to zwitterionic glycine in aqueous solution
Authors: Takenaka Norio , Kitamura Yukichi , Koyano Yoshiyuki , Nagaoka Masataka
Published: July 2012

An efficient methodology is presented to improve the QM description of solute-solvent interactions in condensed systems within the quantum mechanical/molecular mechanical (QM/MM) framework. It is based on the recently developed new treatment of the adaptive multiscale QM/MM-MD method, i.e., the number-adaptive multiscale method that includes the close solvent molecules around the solute into QM region and enables them to flow across the boundary between the QM and MM regions. We have applied it to zwitterionic (ZW) glycine molecule in aqueous solution, and investigated the hydration structures and charge distributions, which are compared with those by the standard (SD) method that only a solute glycine molecule is treated quantum mechanically. It is shown that the total energy and temperature are satisfactorily conserved, providing reasonable hydration numbers and induced polarization of ZW glycine molecule in aqueous solution. In contrast, the SD method is found overestimated the hydration numbers in comparison to the experimental ones due to the inappropriate expression of the electron distribution. In conclusion, the present method should become quite useful as the quantitative statistical sampling method to study various chemical phenomena in condensed systems.
Low energy (e, 2e) study from the 1t2 orbital of CH4
Authors: Xu S. , Chaluvadi Hari , Ren X. , Pflüger T. , Senftleben A. , Ning C. G. , Yan S. , Zhang P. , Yang J. , Ma X. , Ullrich J. , Madison D. H. , Dorn A.
Published: July 2012

Single ionization of the methane (CH4) 1t2 orbital by 54 eV electron impact has been studied experimentally and theoretically. The measured triple differential cross sections cover nearly a 4π solid angle for the emission of low energy electrons and a range of projectile scattering angles. Experimental data are compared with theoretical calculations from the distorted wave Born approximation and the molecular three-body distorted wave models. It is found that theory can give a proper description of the main features of experimental cross section only at smaller scattering angles. For larger scattering angles, significant discrepancies between experiment and theory are observed. The importance of the strength of nuclear scattering from the H-nuclei was theoretically tested by reducing the distance between the carbon nuclei and the hydrogen nuclei and improved agreement with experiment was found for both the scattering plane and the perpendicular plane.
Output errors of atomic force microscopy in heterogeneous materials
Authors: Nima Mahmoodi S. , Salehi-Khojin Amin
Published: July 2012

We have used multiple scale approach to obtain a complete close form solution for scanning system of an atomic force microscopy (AFM) and uncover unexpected errors in the AFM system. We find out that the change in the modulus of elasticity of a sample will lead to a phase shift and jump phenomenon in the frequency response. The readout of the AFM probe amplitude will also be affected accordingly. These results indicate that AFM could produce significant errors in the interface regions of heterogeneous materials. In such a case, AFM may mistakenly consider the change in mechanical properties as the change in topography of the surface. The error associated with this condition must be compensated by a post-processing of collected data.
Melting curves and entropy of fusion of body-centered cubic tungsten under pressure
Authors: Liu Chun-Mei , Chen Xiang-Rong , Xu Chao , Cai Ling-Cang , Jing Fu-Qian
Published: July 2012

The melting curves and entropy of fusion of body-centered cubic (bcc) tungsten (W) under pressure are investigated via molecular dynamics (MD) simulations with extended Finnis-Sinclair (EFS) potential. The zero pressure melting point obtained is better than other theoretical results by MD simulations with the embedded-atom-method (EAM), Finnis-Sinclair (FS) and modified EAM potentials, and by ab initio MD simulations. Our radial distribution function and running coordination number analyses indicate that apart from the expected increase in disorder, the main change on going from solid to liquid is thus a slight decrease in coordination number. Our entropy of fusion of W during melting, ΔS, at zero pressure, 7.619 J/mol·K, is in good agreement with the experimental and other theoretical data. We found that, with the increasing pressure, the entropy of fusion ΔS decreases fast first and then oscillates with pressure; when the pressure is higher than 100 GPa, the entropy of fusion ΔS is about 6.575 ± 0.086 J/mol·K, which shows less pressure effect.
Frequency tunable x-ray/γ-ray source via Thomson backscattering on flying mirror from laser foil interaction
Authors: Wen Meng , Jin Luling , Lu Yuanrong , Chen Jiaer , Yan Xueqing
Published: July 2012

A scheme to generate a frequency tunable x-ray/γ-ray source via Thomson backscattering is proposed. In this model, a few-cycle drive pulse with relativistic intensity interacts with a target (combined with a thin and a thick foil) to produce a flying mirror, and a counter propagating probe pulse is applied to generate a high frequency pulse on it. By adjusting the separation between these two foils, the frequency of the Thomson backscattering light generated from the flying mirror can be tuned in a range from ωL to >106ωL, i.e., x-ray or γ-ray with tunable frequency is obtained. The energy dispersion of the flying mirror, as well as the spectrum width of the Thomson backscattering are studied.
The ‘end of pan-Arabism’ revisited: reflections on the Arab Spring
Authors: Sawani Youssef Mohamed
Published: July 2012

This article draws on implications of the Arab Spring so as to elucidate the dynamics that characterize its revolutions. The analysis builds upon the results of major public opinion surveys conducted in the Arab world, both immediately before and after the Arab Spring, in order to facilitate the identification of developments that shape the relationship between Arabism and Islamism in the context of mass media, the demographic ‘youth bulge’ and Arab ongoing intellectual debates. The argument advanced here is that the Arab Spring consolidates the view that Arabism and Islamism have maintained their position and hold on public opinion and prevailing attitudes as the primary and inseparable trends of Arab thought. The interaction and shifting relative weights of both trends provide the context for the identity, conceptual outlook and reciprocal framework of contemporary Arabs; and the Arab Spring seems only to confirm the two trends as constituting the essential point of reference and departure for Arabs. Within this context and scope of analysis this article traces the emergence of a ‘historical mass’ for change that, coupled with an indelibly engrained link between the two trends is opening up a new conceptual sphere and public space for the emergence of a new Arabism. Such development is also supported by the role of mass media and the thoughtful intellectual contributions that have been advancing a new Arab paradigm which further refutes the ‘End of Arabism’ thesis.
Acute promyelocytic leukemia, arsenic, and PML bodies
Authors: de Thé Hugues , Le Bras Morgane , Lallemand-Breitenbach Valérie
Published: July 2012

Acute promyelocytic leukemia (APL) is driven by a chromosomal translocation whose product, the PML/retinoic acid (RA) receptor α (RARA) fusion protein, affects both nuclear receptor signaling and PML body assembly. Dissection of APL pathogenesis has led to the rediscovery of PML bodies and revealed their role in cell senescence, disease pathogenesis, and responsiveness to treatment. APL is remarkable because of the fortuitous identification of two clinically effective therapies, RA and arsenic, both of which degrade PML/RARA oncoprotein and, together, cure APL. Analysis of arsenic-induced PML or PML/RARA degradation has implicated oxidative stress in the biogenesis of nuclear bodies and SUMO in their degradation.