bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of representation mapping to capture abstraction in problem solving in different courses in chemistry
Authors: Sevian H. , Bernholt S. , Szteinberg G. A. , Auguste S. , Pérez L. C.
Published: April 2015

A perspective is presented on how the representation mapping framework by Hahn and Chater (1998) may be used to characterize reasoning during problem solving in chemistry. To provide examples for testing the framework, an exploratory study was conducted with students and professors from three different courses in the middle of the undergraduate chemistry curriculum. Each participant's reasoning while solving exam problems was characterized by comparing the stored knowledge representation used as a resource and the new instance representation associated with the problem being solved. Doing so required consideration of two ways in which abstraction occurs: abstractness of representations, and abstracting while using representations. The representation mapping framework facilitates comparison of the representations and how they were used. This resulted in characterization of reasoning as memory-bank or rule-based (rules processes), or similarity-based or prototype (similarity processes). Rules processes were observed in all three courses. Similarity-based reasoning seldom occurred in students, but was common to all of the professors’ problem solving, though with higher abstractness than in students. Examples from the data illustrate how representation mapping can be used to examine abstraction in problem solving across different kinds of problems and in participants with different levels of expertise. Such utility could permit identifying barriers to abstraction capacity and may facilitate faculty assessment development.
Dual stimuli-responsive self-assembly transition in zwitterionic/anionic surfactant systems
Authors: Li Wei , Yang Yanjuan , Liu Lifei , Tan Xiuniang , Luo Tian , Shen Junya
Published: April 2015

Realization of reversible vesicle–micelle transitions in zwitterionic/anionic mixed surfactant systems by temperature and pH dual stimuli.
Facile fabrication of a magnetically induced structurally colored fiber and its strain-responsive properties
Authors: Shang Shenglong , Liu Zhifu , Zhang Qinghong , Wang Hongzhi , Li Yaogang
Published: April 2015

A magnetically induced structurally colored fiber, which can be used as a strain sensor, has been fabricated in this article.
Rational design and in situ fabrication of MnO2@NiCo2O4 nanowire arrays on Ni foam as high-performance monolith de-NOx catalysts
Authors: Liu Yan , Xu Jing , Li Hongrui , Cai Sixiang , Hu Hang , Fang Cheng , Shi Liyi , Zhang Dengsong
Published: April 2015

MnO2@NiCo2O4 nanowire arrays on Ni foam were designed and developed as high-performance monolith de-NOx catalysts.
Calcium phosphate nanocapsule crowned multiwalled carbon nanotubes for pH triggered intracellular anticancer drug release
Authors: Banerjee Shashwat S. , Todkar Kiran J. , Khutale Ganesh V. , Chate Govind P. , Biradar Ankush V. , Gawande Manoj B. , Zboril Radek , Khandare Jayant J.
Published: April 2015

A pH-responsive carbon nanotube based carrier crowned with a pore-blocking calcium phosphate nanocapsule is developed for intracellular anticancer drug delivery.
Luminous composite ultrathin films of the DCM dye assembled with layered double hydroxides and its fluorescence solvatochromism properties for polarity sensors
Authors: Qin Yumei , Zhang Ping , Lai Lincong , Tian Zeyun , Zheng Shufang , Lu Jun
Published: April 2015

The PS-PAA@DCM/LDH ordered ultrathin films were fabricated by layer by layer method, and exhibited fast and reversible solvatochromism fluorescence towards solvent vapors.
Utility of a Language Screening Measure for Predicting Risk for Language Impairment in Bilinguals
Authors: Lugo-Neris Mirza J. , Peña Elizabeth D. , Bedore Lisa M. , Gillam Ronald B.
Published: April 2015

Purpose

This study evaluated the accuracy of an experimental version of the Bilingual English Spanish Oral Screener (BESOS; Peña, Bedore, Iglesias, Gutiérrez-Clellen, & Goldstein, 2008) for predicting the long-term risk for language impairment (LI) for a matched group of preschool-aged Spanish–English bilingual children with and without LI.

Method

A total of 1,029 Spanish–English bilingual children completed the BESOS before entering kindergarten. A subset of 167 participants completed a follow-up language evaluation in 1st grade. Twenty-one of these children were identified as having LI and were matched to a group of 21 typically developing peers from the larger sample. A series of discriminant analyses were used to determine the combination of scores on the BESOS that most accurately predicted 2 years later which children presented with and without LI.

Results

The linear combination of the semantics and morphosyntax scores in the best language resulted in predictive sensitivity of 95.2% and predictive specificity of 71.4%, with an overall accuracy of 81% for predicting risk for LI.

Conclusion

A bilingual language screener administered before kindergarten can be useful for predicting risk for LI in bilingual children in 1st grade.
On‐line parameter identification of power plant characteristics based on phasor measurement unit recorded data using differential evolution and bat inspired algorithm
Authors: Rashidi Farzan , Abiri Ebrahim , Niknam Taher , Salehi Mohammad Reza
Published: April 2015

Parameter estimation and dynamic modelling of power systems and their components are basis of design, planning and stability or security assessment in power systems. This study considers the estimation of power system model parameters by a global identification framework based on the maximum‐likelihood principle. The proposed framework is formulated as a non‐linear optimisation problem, which is solved by a hybrid method based on the bat‐inspired algorithm and differential evolution method. The combination of these algorithms makes the hybrid method faster and it obtains closer to the global minimum than a pure global method. Since noise and model uncertainties are inherent parts of system identification, the effect of these factors on the performance of the proposed identification framework are studied. Results based on synthetic data in frequency domain show that the estimated parameters are close to the correct values even in the presence of significant measurement noise and considerable uncertainties.
L’approche orthodontico-chirurgicale revisitée
Authors: Ghoubril Joseph , Kmeid Roland , Nassar Rania , Amm Elie , Mansour Marwan , Akl Roula
Published: April 2015

La préparation orthodontique est la clé du succès d’une chirurgie orthognathique. Ainsi
la détection et la correction des compensations dentaires favorisent la correction des
décalages et déficits squelettiques. Les objectifs orthodontiques pré-chirurgicaux sont
importants à définir dès le début du traitement et ne doivent pas toujours inclure le
nivellement complet des arcades, la fermeture complète des espaces, ou l’intercuspidation
idéale. La préparation orthodontique dicte les mouvements squelettiques qui sont possibles
au moment de la chirurgie. Différents types de malocclusions présentent des compensations
dentaires caractéristiques qui peuvent être identifiées et décrites. La planification
appropriée, l’individualisation et la communication entre le chirurgien et l’orthodontiste
sont critiques afin d’éviter certains pièges dans la préparation orthodontique.
Comment informer et accompagner efficacement un patient pour
une chirurgie orthognathique ?
Authors: Binhas Edmond
Published: April 2015

La chirurgie orthognathique a tendance à se développer ces dernières années. Pourtant,
c’est souvent une notion confuse et effrayante dans l’esprit de nombreux patients. Les
orthodontistes, de leurs côtés, hésitent à la proposer car ils ne sont pas à l’aise avec
la conduite à tenir. Comment établir un lien de confiance avec un patient ? Quelles sont
leurs questions ? Comment annoncer en douceur la chirurgie ? Comment coordonner l’approche
pluridisciplinaire ? Tout autant de questions auxquelles l’auteur tente d’apporter un
éclairage. Il livre des outils pour une planification préopératoire détaillée et
minutieuse, toujours dans l’objectif d’un accompagnement professionnel du patient.
L’orthodontiste sera ainsi mieux armé pour aborder avec lui le sujet de la chirurgie
orthognathique en toute quiétude.
Ostéotomie mandibulaire orthognathique et positionnement
condylien : point et innovation
Authors: Laurentjoye Mathieu , Charton Jérôme , Boileau Marie-José
Published: April 2015

Les articulations temporo-mandibulaires fonctionnent en synergie avec l’occlusion
dentaire, dans le cadre du système manducateur. La prise en compte du condyle mandibulaire
par l’orthodontiste et le chirurgien orthognathique est fondamentale car un problème de
positionnement condylien pourrait entraîner un trouble occlusal avec risque de récidive et
un risque d’apparition, de décompensation ou d’aggravation d’une dysfonction
temporo-mandibulaire. Nous avons voulu répondre à trois questions : Quelle est la position
post-opératoire du condyle en chirurgie orthognathique ? Quel est l’intérêt de
repositionner le condyle ? Quels sont les moyens pour contrôler la position du condyle ?
Enfin, à la lumière de ces réponses, nous présentons un dispositif innovant de
positionnement occlusal et condylien pour les ostéotomies mandibulaires basé sur des
méthodes de planification chirurgicale informatisées. Il s’agit d’un guide en trois
dimensions imprimé permettant de positionner les condyles dans la position choisie de
manière précise, simple, reproductible, indépendante de l’expérience de l’opérateur, mais
aussi rapide et économique.
Comparison of the order of magnetic phase transitions in several magnetocaloric materials using the rescaled universal curve, Banerjee and mean field theory criteria
Authors: Burrola-Gándara L. A. , Santillan-Rodriguez C. R. , Rivera-Gomez F. J. , Saenz-Hernandez R. J. , Botello-Zubiate M. E. , Matutes-Aquino J. A.
Published: April 2015

Magnetocaloric materials with second order phase transition near the Curie temperature can be described by critical phenomena theory. In this theory, scaling, universality, and renormalization are key concepts from which several phase transition order criteria are derived. In this work, the rescaled universal curve, Banerjee and mean field theory criteria were used to make a comparison for several magnetocaloric materials including pure Gd, SmCo1.8Fe0.2, MnFeP0.46As0.54, and La0.7Ca0.15Sr0.15MnO3. Pure Gd, SmCo1.8Fe0.2, and La0.7Ca0.15Sr0.15MnO3 present a collapse of the rescaled magnetic entropy change curves into a universal curve, which indicates a second order phase transition; applying Banerjee criterion to H/σ vs σ2 Arrot plots and the mean field theory relation |ΔSM| ∝ (μ0H/Tc)2/3 for the same materials also determines a second order phase transition. However, in the MnFeP0.46As0.54 sample, the Banerjee criterion applied to the H/σ vs σ2 Arrot plot indicates a first order magnetic phase transition, while the mean field theory prediction for a second order phase transition, |ΔSM| ∝ (μ0H/Tc)2/3, describes a second order behavior. Also, a mixture of first and second order behavior was indicated by the rescaled universal curve criterion. The diverse results obtained for each criterion in MnFeP0.46As0.54 are apparently related to the magnetoelastic effect and to the simultaneous presence of weak and strong magnetism in Fe (3f) and Mn (3g) alternate atomic layers, respectively. The simultaneous application of the universal curve, the Banerjee and the mean field theory criteria has allowed a better understanding about the nature of the order of the phase transitions in different magnetocaloric materials.
Energy dissipation channels affecting photoluminescence from resonantly excited Er3+ ions doped in epitaxial ZnO host films
Authors: Akazawa Housei , Shinojima Hiroyuki
Published: April 2015

We identified prerequisite conditions to obtain intense photoluminescence at 1.54 μm from Er3+ ions doped in ZnO host crystals. The epitaxial ZnO:Er films were grown on sapphire C-plane substrates by sputtering, and Er3+ ions were resonantly excited at a wavelength of 532 nm between energy levels of 4I15/2 and 2H11/2. There is a threshold deposition temperature between 500 and 550 °C, above which epitaxial ZnO films become free of miss-oriented domains. In this case, Er3+ ions are outside ZnO crystallites, having the same c-axis lattice parameters as those of undoped ZnO crystals. The improved crystallinity was correlated with enhanced emissions peaking at 1538 nm. Further elevating the deposition temperature up to 650 °C generated cracks in ZnO crystals to relax the lattice mismatch strains, and the emission intensities from cracked regions were three times as large as those from smooth regions. These results can be consistently explained if we assume that emission-active Er3+ ions are those existing at grain boundaries and bonded to single-crystalline ZnO crystallites. In contrast, ZnO:Er films deposited on a ZnO buffer layer exhibited very weak emissions because of their degraded crystallinity when most Er3+ ions were accommodated into ZnO crystals. Optimizing the degree of oxidization of ZnO crystals is another important factor because reduced films suffer from non-radiative decay of excited states. The optimum Er content to obtain intense emissions was between 2 and 4 at. %. When 4 at. % was exceeded, the emission intensity was severely attenuated because of concentration quenching as well as the degradation in crystallinity. Precipitation of Er2O3 crystals was clearly observed at 22 at. % for films deposited above 650 °C. Minimizing the number of defects and impurities in ZnO crystals prevents energy dissipation, thus exclusively utilizing the excitation energy to emissions from Er3+ ions.
Preparation of Co2FeSn Heusler alloys by electrodeposition method
Authors: Watanabe Nobuaki , Sano Katsuhito , Tasugi Naoya , Yamaguchi Taiki , Yamamoto Akihiro , Ueno Misa , Sumiyoshi Rie , Arakawa Tomiyuki , Koiwa Ichiro
Published: April 2015

We propose a new method for preparing Heusler alloys on the basis of the electrodeposition. The alloy composition is controllable by the deposition potential. The composition ratio of (Co, Fe) and Sn is inversely proportional to the deposition potential. The effect of deposition potential on alloy composition, surface morphology, crystal structure, and magnetic properties of the samples was investigated. The (Co, Fe) vs. Sn alloy composition displayed an inverse dependence on the deposition potential. According to the magnetic measurement, the obtained Co2FeSn composition alloy showed ferromagnetic properties. The coercivity shows the minimum value in the stoichiometric samples.
Molecular dynamical simulations of melting behaviors of metal clusters
Authors: Hamid Ilyar , Fang Meng , Duan Haiming
Published: April 2015

The melting behaviors of metal clusters are studied in a wide range by molecular dynamics simulations. The calculated results show that there are fluctuations in the heat capacity curves of some metal clusters due to the strong structural competition; For the 13-, 55- and 147-atom clusters, variations of the melting points with atomic number are almost the same; It is found that for different metal clusters the dynamical stabilities of the octahedral structures can be inferred in general by a criterion proposed earlier by F. Baletto et al. [J. Chem. Phys. 116 3856 (2002)] for the statically stable structures.
Techno-economic analysis of standalone photovoltaic/wind hybrid system for application in isolated hamlets of North-East India
Authors: Bhakta S. , Mukherjee V. , Shaw B.
Published: April 2015

This paper investigates the techno-economic analysis of standalone PV/wind hybrid system for remote household in North East (NE) region of India, where grid connectivity is not a feasible option. HOMER simulation software is used for sizing, optimization, and to perform the economical analysis of the hybrid system. Sensitivity analysis is carried out with solar radiation data, wind speed data, cost of PV and wind system for a 1 kW PV/wind hybrid system. The analysis is made on the assumption of an annual peak, scaled annual average, and the average load of 694 W, 3.95 kWh/day, and 0.165 kW, respectively, for a remote household. The optimal sizing, cost of electricity (COE), battery profile, and converter profile of PV/wind hybrid system for different NE states are presented in this paper. The outcome of this study shows that COE for the NE states is found to be in the range of 0.271–0.510 $/kWh, which is a acceptable margin and a hybrid PV/wind system will go a long way in addressing the shortage of power faced by a large section of the population on daily basis in the rural areas of the aforementioned region.
Distribution and habitat preference of the broad-toothed rat (Mastacomys fuscus) in the Australian Capital Territory, Australia
Authors: Milner Richard N. C. , Starrs Danswell , Hayes Greg , Evans Murray C.
Published: April 2015

The broad-toothed rat (Mastacomys fuscus) is a small to medium-sized rodent found in south-eastern Australia. Recent surveys across the southern portion of its range indicate that the species is in decline, and climate change has been identified as a key threat to the localised persistence of this species. The present study reports on a rapid field survey across 14 high montane and subalpine sites (including moist tussock grassland, sedgelands, heathlands and bogs) in the southern Australian Capital Territory, Australia. M. fuscus scats were recorded along transects, and habitat, vegetation, distance to drainage lines and disturbance due to feral animals were recorded. Relative abundance of M. fuscus was positively related to specific vegetation types (heath, sedge and Poa) and site size. Conversely, relative abundance of M. fuscus was negatively related to disturbance due to feral animals, and distance from creek drainage lines. This study indicates that M. fuscus has specific habitat preferences and threats associated with environmental change and introduced species may threaten populations in the Australian Capital Territory.
Prevalence of pilus genes in pneumococci isolated from healthy preschool children in Iceland: association with vaccine serotypes and antibiotic resistance
Authors: Hjálmarsdóttir Martha Á. , Pétursdóttir Brynhildur , Erlendsdóttir Helga , Haraldsson Gunnsteinn , Kristinsson Karl G.
Published: April 2015

Objectives

The objective of this study was to investigate the prevalence of pilus islets [pilus islet 1 (PI-1) and pilus islet 2 (PI-2)] in pneumococcal isolates from healthy Icelandic preschool children attending day care centres, prior to the introduction of conjugated pneumococcal vaccine, and the association of the pilus islets with vaccine serotypes and antibiotic resistance.

Methods

Nasopharyngeal swabs were collected from 516 healthy children attending day care centres in Reykjavik in March and April 2009. Infant vaccination was started in 2011, thus the great majority of the children were unvaccinated. Pneumococci were cultured selectively, tested for antimicrobial susceptibility and serotyped. The presence of PI-1 and PI-2 was detected using PCR.

Results

A total of 398 viable isolates were obtained of which 134 (33.7%) showed the presence of PI-1. PI-1-positive isolates were most often seen in serotype 19F [30/31 (96.8%)] and were of clade I, and in 6B [48/58 (82.8%)] of clade II. PI-2-positive isolates were most common in serotype 19F [27/31 (87.1%)]; all of them were also PI-1 positive. Of the PI-1-positive and PI-2-positive isolates, 118 (88.1%) and 31 (81.6%), respectively, were of vaccine serotypes. Both PI-1 and PI-2 were more often present in penicillin-non-susceptible pneumococci (PNSP) than in penicillin-susceptible pneumococci [PI-1 in 41/58 (70.7%) and 93/340 (27.4%), respectively, and PI-2 in 28/58 (48.3%) and 10/340 (2.9%), respectively].

Conclusions

Genes for PI-1 and/or PI-2 in pneumococci isolated from healthy Icelandic children are mainly found in isolates of vaccine serotypes and in PNSP isolates belonging to multiresistant international clones that have been endemic in the country.
Leveraging health information technology to achieve the “triple aim” of healthcare reform
Authors: Sheikh Aziz , Sood Harpreet S , Bates David W
Published: April 2015

Objective To investigate experiences with leveraging health information technology (HIT) to improve patient care and population health, and reduce healthcare expenditures.

Materials and methods In-depth qualitative interviews with federal government employees, health policy, HIT and medico-legal experts, health providers, physicians, purchasers, payers, patient advocates, and vendors from across the United States.

Results The authors undertook 47 interviews. There was a widely shared belief that Health Information Technology for Economic and Clinical Health (HITECH) had catalyzed the creation of a digital infrastructure, which was being used in innovative ways to improve quality of care and curtail costs. There were however major concerns about the poor usability of electronic health records (EHRs), their limited ability to support multi-disciplinary care, and major difficulties with health information exchange, which undermined efforts to deliver integrated patient-centered care. Proposed strategies for enhancing the benefits of HIT included federal stimulation of competition by mandating vendors to open-up their application program interfaces, incenting development of low-cost consumer informatics tools, and promoting Congressional review of the The Health Insurance Portability and Accountability Act (HIPPA) to optimize the balance between data privacy and reuse. Many underscored the need to “kick the legs from underneath the fee-for-service model” and replace it with a data-driven reimbursement system that rewards high quality care.

Conclusions The HITECH Act has stimulated unprecedented, multi-stakeholder interest in HIT. Early experiences indicate that the resulting digital infrastructure is being used to improve quality of care and curtail costs. Reform efforts are however severely limited by problems with usability, limited interoperability and the persistence of the fee-for-service paradigm—addressing these issues therefore needs to be the federal government’s main policy target.
Automated methods for the summarization of electronic health records
Authors: Pivovarov Rimma , Elhadad Noémie
Published: April 2015

Objectives This review examines work on automated summarization of electronic health record (EHR) data and in particular, individual patient record summarization. We organize the published research and highlight methodological challenges in the area of EHR summarization implementation.

Target audience The target audience for this review includes researchers, designers, and informaticians who are concerned about the problem of information overload in the clinical setting as well as both users and developers of clinical summarization systems.

Scope Automated summarization has been a long-studied subject in the fields of natural language processing and human–computer interaction, but the translation of summarization and visualization methods to the complexity of the clinical workflow is slow moving. We assess work in aggregating and visualizing patient information with a particular focus on methods for detecting and removing redundancy, describing temporality, determining salience, accounting for missing data, and taking advantage of encoded clinical knowledge. We identify and discuss open challenges critical to the implementation and use of robust EHR summarization systems.
Preexisting Immunity, More Than Aging, Influences Influenza Vaccine Responses
Authors: Reber Adrian J. , Kim Jin Hyang , Biber Renata , Talbot H. Keipp , Coleman Laura A. , Chirkova Tatiana , Gross F. Liaini , Steward-Clark Evelene , Cao Weiping , Jefferson Stacie , Veguilla Vic , Gillis Eric , Meece Jennifer , Bai Yaohui , Tatum Heather , Hancock Kathy , Stevens James , Spencer Sarah , Chen Jufu , Gargiullo Paul , Braun Elise , Griffin Marie R. , Sundaram Maria , Belongia Edward A. , Shay David K. , Katz Jacqueline M. , Sambhara Suryaprakash
Published: April 2015

Background.  Influenza disproportionately impacts older adults while current vaccines have reduced effectiveness in the older population.

Methods.  We conducted a comprehensive evaluation of cellular and humoral immune responses of adults aged 50 years and older to the 2008–2009 seasonal trivalent inactivated influenza vaccine and assessed factors influencing vaccine response.

Results.  Vaccination increased hemagglutination inhibition and neutralizing antibody; however, 66.3% of subjects did not reach hemagglutination inhibition titers ≥ 40 for H1N1, compared with 22.5% for H3N2. Increasing age had a minor negative impact on antibody responses, whereas prevaccination titers were the best predictors of postvaccination antibody levels. Preexisting memory B cells declined with age, especially for H3N2. However, older adults still demonstrated a significant increase in antigen-specific IgG+ and IgA+ memory B cells postvaccination. Despite reduced frequency of preexisting memory B cells associated with advanced age, fold-rise in memory B cell frequency in subjects 60+ was comparable to subjects age 50–59.

Conclusions.  Older adults mounted statistically significant humoral and cell-mediated immune responses, but many failed to reach hemagglutination inhibition titers ≥40, especially for H1N1. Although age had a modest negative effect on vaccine responses, prevaccination titers were the best predictor of postvaccination antibody levels, irrespective of age.
Corynebacterium pseudotuberculosis Pneumonia in a Veterinary Student Infected During Laboratory Work
Authors: Heggelund Lars , Gaustad Peter , Håvelsrud Othilde Elise , Blom Jochen , Borgen Lars , Sundset Arve , Sørum Henning , Frøland Stig Sophus
Published: April 2015

We present a case of Corynebacterium pseudotuberculosis pneumonia in a veterinary student, with molecular genetic evidence of acquisition during laboratory work, an observation relevant for laboratory personnel working with C pseudotuberculosis isolates. The patient was clinically cured with 14 months trimethoprim/sulfamethoxazole and rifampicin combination treatment.
A Soil Bioassay for Predicting the Risk of Spinach Fusarium wilt
Authors: Gatch Emily W. , du Toit Lindsey J.
Published: April 2015

The maritime Pacific Northwest is the only region of the United States suitable for production of spinach seed, a cool-season, daylength-sensitive crop. However, the acidic soils of this region are highly conducive to spinach Fusarium wilt, caused by Fusarium oxysporum f. sp. spinaciae. Rotations of at least 10 to 15 years between spinach seed crops are necessary to reduce the high risk of losses to this disease. The objectives of this study were to develop a greenhouse soil bioassay to assess the relative risk of Fusarium wilt in fields intended for spinach seed production, and to identify soil chemical and physical properties associated with conduciveness to this disease. Preliminary bioassays established a protocol for growing spinach plants in a greenhouse environment and inducing Fusarium wilt symptoms so that the bioassay can be completed in <2 months. Test soils with a range of Fusarium wilt inoculum potentials, and three spinach inbred parent lines (highly susceptible, moderately susceptible, and moderately resistant to Fusarium wilt) were used to evaluate sensitivity of the bioassay to different levels of risk of Fusarium wilt. Then, from 2010 to 2013, spinach seed growers and stakeholders submitted soil samples from 147 fields for evaluation with the bioassay. The fields were each under consideration for planting a spinach seed crop, yet the bioassay revealed a wide range in Fusarium wilt inoculum potential among soil samples. Differences in susceptibility to Fusarium wilt of the three inbred lines were key to detecting differences in wilt risk among soils. Visits to spinach seed crops planted in fields evaluated in the bioassay, as well as test plots of the three inbred lines planted in growers’ seed crops, confirmed the predictive value of the bioassay for Fusarium wilt risk. Correlation analyses for 23 soil properties revealed significant relationships of 15 soil properties with the Fusarium wilt potential of a soil, but the correlations were influenced significantly by susceptibility of the inbred line to Fusarium wilt (13, 10, and 8 soil properties correlated significantly with Fusarium wilt risk for the susceptible, moderate, and partially resistant inbreds, respectively). Multiple regression analyses identified different statistical models for prediction of Fusarium wilt risk depending on the spinach inbred line, but the best fitting model explained <34% of the variability in Fusarium wilt risk among 121 fields evaluated in the soil bioassay. Thus, no model was robust enough to replace the bioassay for the purpose of predicting Fusarium wilt risk.
Dose-dependent Association between Intermediate-acting Neuromuscular-blocking Agents and Postoperative Respiratory Complications
Authors: McLean Duncan J. , Diaz-Gil Daniel , Farhan Hassan N. , Ladha Karim S. , Kurth Tobias , Eikermann Matthias
Published: April 2015

AbstractAbstract

In a review of nearly 50,000 subjects, use of intermediate-acting neuromuscular blockers was associated with a dose-dependent increase in pulmonary complications. Neostigmine also was associated with a dose-dependent increase in pulmonary complications although exploratory analysis suggested that this reflected lack of neostigmine dose adjustment using neuromuscular transmission monitoring.

Background:

Duration of action increases with repeated administration of neuromuscular-blocking agents, and intraoperative use of high doses of neuromuscular-blocking agent may affect respiratory safety.

Methods:

In a hospital-based registry study on 48,499 patients who received intermediate-acting neuromuscular-blocking agents, the authors tested the primary hypothesis that neuromuscular-blocking agents are dose dependently associated with the risk of postoperative respiratory complications. In the secondary analysis, the authors evaluated the association between neostigmine dose given for reversal of neuromuscular-blocking agents and respiratory complications. Post hoc, the authors evaluated the effects of appropriate neostigmine reversal (neostigmine ≤60 μg/kg after recovery of train-of-four count of 2) on respiratory complications. The authors controlled for patient-, anesthesia-, and surgical complexity–related risk factors.

Results:

High doses of neuromuscular-blocking agents were associated with an increased risk of postoperative respiratory complications (n = 644) compared with low doses (n = 205) (odds ratio [OR], 1.28; 95% CI, 1.04 to 1.57). Neostigmine was associated with a dose-dependent increase in the risk of postoperative respiratory complications (OR, 1.51; 95% CI, 1.25 to 1.83). Post hoc analysis revealed that appropriate neostigmine reversal eliminated the dose-dependent association between neuromuscular-blocking agents and respiratory complications (for neuromuscular-blocking agent effects with appropriate reversal: OR, 0.98; 95% CI, 0.63 to 1.52).

Conclusions:

The use of neuromuscular-blocking agents was dose dependently associated with increased risk of postoperative respiratory complications. Neostigmine reversal was also associated with a dose-dependent increase in the risk of respiratory complications. However, the exploratory data analysis suggests that the proper use of neostigmine guided by neuromuscular transmission monitoring results can help eliminate postoperative respiratory complications associated with the use of neuromuscular-blocking agents.
Lower Extremity Deformity Management in MPS IVA, Morquio-Brailsford Syndrome: Preliminary Report of Hemiepiphysiodesis Correction of Genu Valgum
Authors: Cooper George A. , Southorn Thomas , Eastwood Deborah M. , Bache C. Edward
Published: April 2015

Background:

Morquio-Brailsford syndrome or mucopolysaccharidosis type IV-A (MPS IV-A) is an inherited metabolic disease in which skeletal deformities can be extreme. An international registry has shown that 46% of patients are unable to walk 200 m and 30% use a wheelchair. Lower limb surgery is performed to restore alignment with the expectation of maintaining mobility. We are, however, not aware of reports correlating function with alignment. This study assesses the role of orthopaedic intervention with reference to anatomic and functional outcome in MPS IV-A: specifically hemiepiphysiodesis correction of genu valgum.

Methods:

Interrogation of the MPS patient database identified 63 patients. Patient demographic and radiographic data were collected along with information on deformity, correction, mobility, and genotype. Genu valgum was assessed by intermalleolar distance and mobility by a standardized 6-minute walk test. Sequential hip anatomy was assessed radiographically.

Results:

Twenty-six surgical hemiepiphysiodesis episodes were performed on 23 patients. There were no cases of implant failure, loosening, or infection. The average intermalleolar distance reduction was 6.12 cm (paired t test, P=0.0001) (95% confidence interval, 7.6-4.7 cm) and the mean change in 6-minute walk test was +69.5 m (P=0.0339). There was no correlation between hip subluxation/dislocation and mobility (Fisher exact test, P=1.000), although hip parameters deteriorated over time. Three patients required repeat 8-plate insertion and 1 a femoral osteotomy.

Conclusions:

Eight-plate hemiepiphysiodesis correction of genu valgum in MPS IV-A is an effective treatment with low complication rates. The insult of surgery is minimal compared with that of osteotomy which can reduce mobility further. Our outcomes suggest that mobility is maintained or improved even in severe genotypes where mobility typically worsens. We have found hip pathology to be less debilitating, but further studies are needed to assess the effect of genu valgum correction upon femoral head subluxation and collapse.

We suggest hemiepiphysiodesis should be considered as part of the treatment strategy for limb alignment in MPS IV-A patients, depending on remaining growth, mobility status, and genotype.

Level of Evidence:

Level IV—therapeutic case series.
Open Versus Arthroscopic Reduction for Tibial Eminence Fracture Fixation in Children
Authors: Watts Chad D. , Larson A. Noelle , Milbrandt Todd A.
Published: April 2015

Background:

Stiffness is a common complication following surgically treated tibial eminence fractures. Fractures can be addressed with either open reduction and internal fixation (ORIF) or arthroscopic reduction and internal fixation (ARIF). We sought to evaluate the effects of surgical approach and other modifiable perioperative factors on postoperative arthrofibrosis. We hypothesized that ARIF would result in a lower risk of arthrofibrosis.

Methods:

We retrospectively reviewed the records of all patients aged 18 years and below treated for tibial eminence fractures at our institution from 1998 to 2014. All patients were treated by either pediatric or sports fellowship-trained orthopaedic surgeons and followed until radiographic union and return of range of motion or treatment for arthrofibrosis (minimum 3 mo).

Results:

Thirty-one patients were included in our analysis, 13 in the ORIF group and 18 in the ARIF group. The groups were similar in regards to sex, age, fracture type, fixation method, and length of postoperative immobilization. However, when compared with the ORIF group, patients in the ARIF group had significantly longer time from injury to surgery (4.2 vs. 6.3 d, P=0.03), operative time (98 vs. 141 min, P=0.02), and tourniquet time (76 vs. 100 min, P=0.006). In the ARIF group, 6 (33.3%) patients acquired arthrofibrosis compared with only 1 (7.7%) patient in the ORIF group. Delaying surgery ≥7 days from injury [hazard ratio (HR)=4.7, P=0.04] and operative time ≥120 minutes (HR=9.1, P=0.03) were risk factors for arthrofibrosis. ARIF was a risk factor in univariate (HR=4.0, P=0.04), but not in multivariate (1.4, P=0.77) analysis.

Conclusions:

Delayed surgery (≥7 d from injury) and prolonged operative times (≥120 min) were significant risk factors for arthrofibrosis. Although ARIF was not an independent risk factor, these patients were exposed to markedly longer wait times before surgery and operative times when compared with ORIF patients. ORIF is a reasonable option for treatment of displaced tibial eminence fractures. Surgeons should approach tibial eminence fractures with whichever mode they can accomplish with higher efficiency.

Level of Evidence:

Level III—therapeutic study.
Titanium Elastic Nailing for Pediatric Tibia Fractures: Do Older, Heavier Kids Do Worse?
Authors: Goodbody Christine M. , Lee Rushyuan J. , Flynn John M. , Sankar Wudbhav N.
Published: April 2015

Background:

Elastic nailing is a common method of fixation for tibial shaft fractures in skeletally immature individuals. Poor outcomes of titanium elastic nails for femoral shaft fractures have been associated with increasing patient age and weight, especially patients weighing >50 kg. Our objective is to determine if there is an upper weight or age limit to the safe and effective use of titanium elastic nails for tibial shaft fractures in the pediatric population.

Methods:

This is a retrospective cohort study of patients who underwent stabilization of a tibial shaft fracture with titanium elastic nails at a large tertiary-care pediatric trauma center. Data collected included patient demographics, injury characteristics, and radiographic data. Weight groups were stratified as ≥ or <50 kg, and age groups as 14 years or older or less than 14 years old. Malunion was defined as 10 degrees of angulation in either the sagittal or coronal plane. Union was defined as bridging of ≥3 cortices on orthogonal radiographs. A significant difference in time to union was considered to be 3 weeks.

Results:

Ninety-five patients were included with a mean age of 12.1 years (range, 6 to 16 y) and a mean weight of 50.2 kg (range, 21 to 122 kg). Malunion rate was similar between weight cohorts: 13.3% (6/45) in the ≥50-kg group and 10% (5/50) in the <50-kg group (P=0.61). Malunion rate was similarly comparable between age groups: 17.6% (6/34) in the 14 years and older group and 8.2% (5/61) in the less than 14-year-old group (P=0.17). There was no statistically significant difference in time to union between weight or age cohorts. In sum, we did not find a significant difference in the rate of malunion or time to healing between younger and older patients or between lighter and heavier patients.

Conclusion:

The use of titanium elastic nails for tibial shaft fractures, unlike for other long bone fractures, seems not to be precluded in older and heavier patients.

Level of Evidence:

Level III.
Hip Instability in Down Syndrome: A Focus on Acetabular Retroversion
Authors: Abousamra Oussama , Bayhan Ilhan A. , Rogers Kenneth J. , Miller Freeman
Published: April 2015

Background:

The aim of this study is to compare acetabular anteversion between children with Down syndrome with or without hip instability. The second aim is to report the surgical experience at our institution in treating unstable hips for this population.

Methods:

All children with Down syndrome who were seen at our institution between 2004 and 2014 were reviewed, and those who had pelvic axial computed tomographic or magnetic resonance imaging scans were identified. Acetabular anteversion was compared between 2 groups: those with hip instability as a single hip pathology and those without hip instability. For patients who had surgery for their unstable hips, demographic, clinical, and surgical data were recorded. Preoperative and last visit radiographs were reviewed. Extrusion index and Tonnis, Sharp, lateral center edge, and neck shaft angles were measured. Presence of Shenton’s line disruption, crossover, and posterior wall signs were recorded. Independent and paired t test, Wilcoxon signed-rank test, and χ2 test were used with a significance level at 0.05.

Results:

Out of 308 children with Down syndrome, there were 10 patients with 13 unstable hips and 13 patients with 26 stable hips who had computed tomographic or magnetic resonance imaging scans. Age and sex distributions were similar (P>0.3) with no difference in acetabular anteversion (P=0.926) between them. Twelve patients (6 boys and 6 girls) had reconstruction for 17 hips. The mean age was 9 years (3 to 15 y) and the mean follow-up was 7 years (1.2 to 17.6 y). Five hips were painful preoperatively and 1 hip was painful at last visit. Radiographic measurements improved significantly (P<0.05). Shenton’s line disruption was found in fewer hips (P=0.001) at last visit with no difference in the crossover and posterior wall signs (P=0.177).

Conclusions:

This report suggests that a wide range of acetabular anteversion measurements exist in children with Down syndrome. After detailed anatomic study of the hip, good results with a low complication rate can be expected over the intermediate term after hip reconstruction.

Level of Evidence:

Level IV—prognostic and therapeutic study.
Treatment of Snapping Scapula Syndrome in Children and Adolescents
Authors: Haus Brian , Nasreddine Adam Y. , Suppan Catherine , Kocher Mininder S.
Published: April 2015

Purpose:

The purpose of this study was to review 2 separate cohorts of young patients treated for snapping scapula: those treated surgically and those managed nonoperatively.

Methods:

A retrospective IRB-approved review was conducted on 18 pediatric aged patients (19 shoulders): 12 patients (average age 13.3) were treated nonoperatively, 6 patients (average age 15.4) (7 shoulders) were treated operatively. Demographic and clinical data were collected from medical records and 2 questionnaires for level of activity, return to sport, subjective satisfaction from treatment, and preoperative/postoperative levels of pain. The American Shoulder and Elbow Society (ASES) score was measured for both groups.

Results:

Mean follow-up for nonoperative patients was 43.7 months (range, 20 to 116 mo). Pretreatment subjective pain levels were 5.2 (scale 1 to 10), posttreatment were 1.5. There was a 75% return to play rate, and an overall 75% satisfaction rate. Posttreatment ASES scores were 90.0. Mean follow-up for surgical patients was 129.5 months (range, 68 to 177 mo). Pretreatment subjective pain level was 8.6, posttreatment was 0.75. There was an 83% return to play rate, and an overall 100% satisfaction rate. There were no complications. Posttreatment ASES scores were 92.6.

Conclusions:

Outcomes for nonoperative treatment of snapping scapula are good for young patients. Surgical management of snapping scapula is a safe and viable treatment option for patients who fail nonoperative treatment.

Level of Evidence:

Level IV.
Outcomes and Complications of Tibial Tubercle Fractures in Pediatric Patients: A Systematic Review of the Literature
Authors: Pretell-Mazzini Juan , Kelly Derek M. , Sawyer Jeffrey R. , Esteban Eva M.A. , Spence David D. , Warner William C. , Beaty James H.
Published: April 2015

Background:

Systematic review of the literature was done to determine (1) the frequency and type of associated injuries, (2) frequency of concomitant Osgood-Schlatter disease, (3) methods of treatment, (4) functional and radiologic outcomes according to fracture type, and (5) complications of tibial tubercle fractures in pediatric patients.

Methods:

A systematic review of the English literature from 1970 to 2013 included 23 eligible articles reporting 336 fractures with a mean follow-up of 33.56 months (range, 5.7 to 115 mo). Fractures were classified by a comprehensive system that included characteristics of previous systems. Clinical outcomes were assessed by a qualitative scale (excellent/fair/poor), the rate of return to preinjury activity, and knee range of motion. Rate of fracture healing, associated injuries (patellar/quadriceps tendon avulsion and meniscal tears), compartment syndrome, and complications were also recorded.

Results:

Mean age at surgery was 14.6 years and the most common fracture reported was type III (50.6%). The overall associated injury rate was 4.1%, most common in type III fractures (4.7%). Compartment syndrome was present in 3.57% of cases. Open reduction and internal fixation were done in 98% of surgical cases. Rates of return to preinjury activity and knee range of motion were 98%, regardless of the type of fracture. Fracture consolidation was achieved in 99.4% of cases. Overall complication rate was 28.3%; removal of an implant because of bursitis (55.8%) was most common. Tenderness/prominence (17.9%) and refracture (6.3%) were also common.

Conclusions:

Treatment of tibial tubercle fractures in adolescents produced good clinical and radiologic results regardless of fracture type, which was more related to potential complications. Fractures with intra-articular involvement tended to present with more associated injuries and to have fair functional outcomes, suggesting that advanced imaging may be justified with these fractures. Complications could be more common than expected without a significant effect on final outcome. Finally, there is a need for longer follow-up to determine long-term outcomes.

Level of Evidence:

Level III—systematic review of level III/IV studies.
The Management of Soft Tissue and Bone Loss in Type IIIB and IIIC Pediatric Open Tibia Fractures
Authors: Laine Jennifer C. , Cherkashin Alexander , Samchukov Mikhail , Birch John G. , Rathjen Karl E.
Published: April 2015

Purpose:

Type III B and C open tibia fractures in children pose a challenge to the orthopaedic surgeon. Limb salvage is the initial goal for the majority of patients, but managing soft-tissue defects and bone loss can be a challenge. The purpose of this study was to evaluate the use of circular external fixation in the management of these injuries.

Methods:

In this retrospective review, we examined children with type IIIB and IIIC open tibial fractures treated with circular external fixation and soft-tissue coverage between 1990 and 2010. Chart review included: mechanism and severity of injury, degree of bone and soft-tissue loss, technique and duration of external fixation, additional procedures, clinical and radiographic outcomes, and complications.

Results:

Eight patients were identified whose average age at the time of injury was 10.4 years (range, 3.8 to 15.3 y). There were 7 type IIIB and 1 type IIIC fractures. All patients received free or rotational soft-tissue flaps. Average bone loss was 5.4 cm (range, 0 to 12 cm). Three techniques of circular external fixation were used, including: (1) static stabilization to allow for soft-tissue coverage and fracture healing, (2) acute shortening with plan for later limb lengthening, and (3) stabilization of the extremity for soft-tissue coverage and intended bone transport. Seven of 8 limbs were salvaged. Of those 7, all were followed to skeletal maturity and ambulating without assistive devices at final follow-up. Three patients had a clinically relevant leg-length discrepancy (≥2 cm). Four of 8 patients required secondary or contralateral procedures.

Conclusions:

Pediatric type IIIB and IIIC tibia fractures are limb-threatening injuries that require dynamic thinking and management as the bone and soft-tissue injuries evolve. We have proposed a general algorithm to guide the treatment of these severe injuries. In our experience, circular external fixation, in conjunction with this algorithm, provides the appropriate stability and environment for managing soft tissue and bone loss and can facilitate limb salvage.

Level of Evidence:

Level IV.