bluuebunny/crossref_metadata_2025 huggingface dataset:
Neutron resonance spin echo with longitudinal DC fields
Authors: Krautloher Maximilian , Kindervater Jonas , Keller Thomas , Häußler Wolfgang
Published: December 2016

We report on the design, construction, and performance of a neutron resonance spin echo (NRSE) instrument employing radio frequency (RF) spin flippers combining RF fields with DC fields, the latter oriented parallel (longitudinal) to the neutron propagation direction (longitudinal NRSE (LNRSE)). The advantage of the longitudinal configuration is the inherent homogeneity of the effective magnetic path integrals. In the center of the RF coils, the sign of the spin precession phase is inverted by a π flip of the neutron spins, such that non-uniform spin precession at the boundaries of the RF flippers is canceled. The residual inhomogeneity can be reduced by Fresnel- or Pythagoras-coils as in the case of conventional spin echo instruments (neutron spin echo (NSE)). Due to the good intrinsic homogeneity of the B0 coils, the current densities required for the correction coils are at least a factor of three less than in conventional NSE. As the precision and the current density of the correction coils are the limiting factors for the resolution of both NSE and LNRSE, the latter has the intrinsic potential to surpass the energy resolution of present NSE instruments. Our prototype LNRSE spectrometer described here was implemented at the resonance spin echo for diverse applications (RESEDA) beamline at the MLZ in Garching, Germany. The DC fields are generated by B0 coils, based on resistive split-pair solenoids with an active shielding for low stray fields along the beam path. One pair of RF flippers at a distance of 2 m generates a field integral of ∼0.5 Tm. The LNRSE technique is a future alternative for high-resolution spectroscopy of quasi-elastic excitations. In addition, it also incorporates the MIEZE technique, which allows to achieve spin echo resolution for spin depolarizing samples and sample environments. Here we present the results of numerical optimization of the coil geometry and first data from the prototype instrument.
Symmetry of Lyapunov exponents in bifurcation structures of one-dimensional maps
Authors: Shimada Yutaka , Takagi Emiko , Ikeguchi Tohru
Published: December 2016

We observe a symmetry of Lyapunov exponents in bifurcation structures of one-dimensional maps in which there exists a pair of parameter values in a dynamical system such that two dynamical systems with these paired parameter values have the same Lyapunov exponent. We show that this is a consequence of the presence of an invariant transformation from a dynamical system with one of the two paired parameter values to that with another parameter value, which does not change natures of dynamical systems.
Experimental setup for temporally and spatially resolved ICCD imaging of (sub)nanosecond streamer plasma
Authors: Huiskamp T. , Sengers W. , Pemen A. J. M.
Published: December 2016

Streamer discharges are efficient non-thermal plasmas for air purification and can be generated in wire-cylinder electrode structures (the plasma reactor). When (sub)nanosecond high-voltage pulses are used to generate the plasma, components like a plasma reactor behave as transmission lines, where transmission times and reflections become important. We want to visually study the influence of these transmission-line effects on the streamer development in the reactor. Therefore, we need a unique experimental setup, which allows us to image the streamers with nanosecond time resolution over the entire length of the plasma reactor. This paper describes the setup we developed for this purpose. The setup consists of a large frame in which a specially designed plasma reactor can be mounted and imaged from below by an intensified charge-coupled device (ICCD) camera. This camera is mounted on a platform which can be moved by a stepper motor. A computer automates all the experiments and controls the camera movement, camera settings, and the nanosecond high-voltage pulse source we use for the experiments. With the automated setup, we can make ICCD images of the entire plasma reactor at different instances of time with nanosecond resolution (with a jitter of less than several hundreds of picoseconds). Consequently, parameters such as the streamer length and width can be calculated automatically.
Grain boundary effects on the optical constants and Drude relaxation times of silver films
Authors: Jiang Yajie , Pillai Supriya , Green Martin A.
Published: December 2016

Silver demonstrates the unique optical properties that make it suitable for various plasmonic applications. Determining the accurate optical constants for silver and investigating its dependence on grain structures are necessary for reliable theoretical predictions. This work investigates the effects of different deposition conditions and the resultant variable grain sizes, upon the optical properties of the silver films in conjunction with ellipsometry and optical characterization. Annealing conditions of substrate SiNx films were also studied to ensure good quality of deposited polycrystalline silver films. The effects of grain sizes of silver on its electronic relaxation times were studied and shown to be consistent with the theoretical electrical resistivity model. This study shows that voids and surface layers can affect the optical constant values and that reproducible results can be obtained by avoiding such artefacts. The results will have implications on the analysis of different silver based nanostructures like nanowires and nanorods where grain boundary scattering can affect the optical and electrical properties like reflection and resistivity.
Mechanisms and rate of dislocation nucleation in aluminum-copper alloys near Guinier-Preston zones
Authors: Bryukhanov I. A. , Larin A. V.
Published: December 2016

This article is devoted to a molecular dynamics simulation study of partial dislocation loop nucleation with respect to its mechanism and rate, and its propagation process under high shear stress in aluminum-copper alloys. The mechanisms of dislocation nucleation near Guinier-Preston (GP) zones of various diameters and concentrations have been analyzed. Dislocation nucleation rates near plain GP Cu-zones with diameters of 3.5, 7.5, and 13.5 nm and at various concentrations have been calculated using the mean lifetime method with temperatures in range of 100 and 700 K. It has been found that depending on the temperature and applied stress, the dislocation can nucleate either from the edge, or from the plain area of a GP zone. The dislocation nucleation is preceded by a generation of defect clusters that are formed due to local opposite atomic shifts in two adjacent (111) planes by the half-length of a Burgers vector of a partial dislocation. The expansion of a partial dislocation loop can be accompanied by the formation of twins via a shift of the atoms in the internal region of the loop. The twin velocity along the direction of the partial dislocation Burgers vector inside the loop can achieve longitudinal sound speed. The speeds of the edge and screw segments of a partial dislocation loop as a function of a shear stress component along the Burgers vector have been estimated. The latter seems to be limited by the shear sound speed.
Structure and electrical properties of epitaxial SrRuO3 thin films controlled by oxygen partial pressure
Authors: Sun Yan , Zhong Ni , Zhang Yuan-Yuan , Qi Rui-Juan , Huang Rong , Tang Xiao-Dong , Yang Ping-Xiong , Xiang Ping-Hua , Duan Chun-Gang
Published: December 2016

SrRuO3 (SRO) thin films have been grown on (001)-oriented SrTiO3 substrate under various oxygen partial pressures (PO2). A typical step-and-terrace surface morphology and coherent epitaxy characteristics are found in the SRO films for high oxygen pressure growth (PO2 ≥ 10 Pa). Under such high PO2, SRO films exhibit metallic behavior over a temperature range of 10 K ≤ T ≤ 300 K. A detailed study on the transport properties of the metallic SRO films reveals that the resistivity (ρ) follows the law ρ(T)-ρ0 ∝ Tx (x = 0.5, 1.5, or 2). Below ferromagnetic transition temperature (Tc), ρ(T) follows T2 dependence below 30 K and T1.5 dependence at T > 30 K, respectively. This result demonstrates that a transition between the Fermi-liquid (FL) and non-Fermi-liquid (NFL) behavior occurs at ∼30 K. Furthermore, ρ(T) follows T0.5 dependence at T > Tc in the paramagnetic metal state. We have found that the FL to NFL transitions as well as the ferromagnetic transition are corresponding to the abnormal peaks in the magnetoresistance curves, suggesting the coupling of electronic and magnetic properties. The transition temperature of FL to NFL for metallic SRO films is almost independent on PO2, while Tc slightly increases with PO2.
A flexible, wave-shaped P(VDF-TrFE)/metglas piezoelectric composite for wearable applications
Authors: You Sujian , Shi Huaduo , Wu Jingen , Shan Liang , Guo Shishang , Dong Shuxiang
Published: December 2016

In this work, a wave-shaped piezoelectric composite (WSPC) made of fine β-phase vinylidene fluoride trifluoroethylene copolymer (P(VDF-TrFE)) polymer and high-elastic FeSiB amorphous alloy (metglas) ribbon has been successfully fabricated for wearable device applications. X-ray diffraction and the Fourier Transform Infrared Spectrum studies reveal P(VDF-TrFE) exhibiting the fine β-phase. Both theoretical analysis and experimental results show that unique wave-shaped structure enhances the electromechanical coupling significantly, because of the combination piezoelectric effects of d33 and d31 modes in P(VDF-TrFE) polymer, as well as the enhanced effective piezoelectric coefficient caused by the pre-stretch in P(VDF-TrFE) film. Two application examples of WSPC, (i) mechanical force sensor or energy harvester, and (ii) the medical blood-pressure pulse sensor, have been investigated, which show that the WSPC is a promising candidate for future wearable device applications.
Shock compression experiments on Lithium Deuteride (LiD) single crystals
Authors: Knudson M. D. , Desjarlais M. P. , Lemke R. W.
Published: December 2016

Shock compression experiments in the few hundred GPa (multi-Mbar) regime were performed on Lithium Deuteride single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17–32 km/s. Measurements included pressure, density, and temperature between ∼190 and 570 GPa along the Principal Hugoniot—the locus of end states achievable through compression by large amplitude shock waves—as well as pressure and density of reshock states up to ∼920 GPa. The experimental measurements are compared with density functional theory calculations, tabular equation of state models, and legacy nuclear driven results that have been reanalyzed using modern equations of state for the shock wave standards used in the experiments.
Broadband optical magnetism in chiral metallic nanohole arrays by shadowing vapor deposition
Authors: Han Chunrui , Tam Wing Yim
Published: December 2016

We show that broadband optical magnetism can be achieved through incorporating multi-scaled 3D metallic meta-elements into Z-shaped nanohole arrays. The broadband effect arises from the excitation of multiple magnetic resonances in the meta-elements at different wavelengths. Moreover, the nanohole arrays exhibit a large transmission difference for left- and right-handed circularly polarized incident light due to the chiral arrangement of the meta-elements. More importantly, we have realized experimentally the broadband behavior for the optical range in Ag nanohole arrays fabricated by using a shadowing vapor deposition method. Our study opens up new opportunities for achieving broadband artificial magnetism at visible frequencies which allows possible applications in plasmonic bio-sensors or energy concentrators.
Thermal conductivity enhancement of laser induced graphene foam upon P3HT infiltration
Authors: Smith M. K. , Luong D. X. , Bougher T. L. , Kalaitzidou K. , Tour J. M. , Cola B. A.
Published: December 2016

Significant research has been dedicated to the exploration of high thermal conductivity polymer composite materials with conductive filler particles for use in heat transfer applications. However, poor particle dispersibility and interfacial phonon scattering have limited the effective composite thermal conductivity. Three-dimensional foams with high ligament thermal conductivity offer a potential solution to the two aforementioned problems but are traditionally fabricated through expensive and/or complex manufacturing methods. Here, laser induced graphene foams, fabricated through a simple and cost effective laser ablation method, are infiltrated with poly(3-hexylthiophene) in a step-wise fashion to demonstrate the impact of polymer on the thermal conductivity of the composite system. Surprisingly, the addition of polymer results in a drastic (250%) improvement in material thermal conductivity, enhancing the graphene foam's thermal conductivity from 0.68 W/m-K to 1.72 W/m-K for the fully infiltrated composite material. Graphene foam density measurements and theoretical models are utilized to estimate the effective ribbon thermal conductivity as a function of polymer filling. Here, it is proposed that the polymer solution acts as a binding material, which draws graphene ligaments together through elastocapillary coalescence and bonds these ligaments upon drying, resulting in greatly reduced contact resistance within the foam and an effective thermal conductivity improvement greater than what would be expected from the addition of polymer alone.
Very high thermoelectric figure of merit found in hybrid transition-metal-dichalcogenides
Authors: Ouyang Yulou , Xie Yuee , Zhang Zhongwei , Peng Qing , Chen Yuanping
Published: December 2016

The search for thermoelectrics with higher figures of merit (ZT) will never stop due to the demand of heat harvesting. Single layer transition metal dichalcogenides (TMD), namely, MX2 (where M is a transition metal and X is a chalcogen), that have electronic band gaps are among the new materials that have been the focus of such research. Here, we investigate the thermoelectric transport properties of hybrid armchair-edged TMD nanoribbons, by using the nonequilibrium Green's function technique combined with the first principles and molecular dynamics methods. We find a ZT as high as 7.4 in hybrid MoS2/MoSe2 nanoribbons at 800 K, creating a new record for ZT. Moreover, the hybrid interfaces by substituting X atoms are more efficient than those by substituting M atoms to tune the ZT. The origin of such a high ZT of hybrid nanoribbons is the high density of the grain boundaries: the hybrid interfaces decrease thermal conductance drastically without a large penalty to electronic conductance.
A simple and compact method for measuring the hydrogen ion fraction of hybrid ion beams
Authors: Jianlin Ke , Changgeng Zhou , Rui Qiu , Yonghong Hu , Bin Liu , Tie He , Li An
Published: December 2016

A simple and compact method for measuring the hydrogen fraction of hybrid ion beams is introduced in this paper. The method is based on the difference of stopping powers for protons and other heavier ions. This method was used in a measurement of the hydrogen ion fraction of a beam produced by a vacuum arc ion source, and was also proposed to be used in quasi-mono-energetic laser accelerators. In the vacuum arc ion source case, results obtained by this method agree well with that measured by time-of-flight spectrometry and magnetic mass analysis methods.
k.p theory of freestanding narrow band gap semiconductor nanowires
Authors: Luo Ning , Liao Gaohua , Xu H. Q.
Published: December 2016

We report on a theoretical study of the electronic structures of freestanding nanowires made from narrow band gap semiconductors GaSb, InSb and InAs. The nanowires are described by the eight-band k.p Hamiltonians and the band structures are computed by means of the finite element method in a mixture basis consisting of linear triangular elements inside the nanowires and constrained Hermite triangular elements near the boundaries. The nanowires with two crystallographic orientations, namely the [001] and [111] orientations, and with different cross-sectional shapes are considered. For each orientation, the nanowires of the three narrow band gap semiconductors are found to show qualitatively similar characteristics in the band structures. However, the nanowires oriented along the two different crystallographic directions are found to show different characteristics in the valence bands. In particular, it is found that all the conduction bands show simple, good parabolic dispersions in both the [001]- and [111]-oriented nanowires, while the top valence bands show double-maximum structures in the [001]-oriented nanowires, but single-maximum structures in the [111]-oriented nanowires. The wave functions and spinor distributions of the band states in these nanowires are also calculated. It is found that significant mixtures of electron and hole states appear in the bands of these narrow band gap semiconductor nanowires. The wave functions exhibit very different distribution patterns in the nanowires oriented along the [001] direction and the nanowires oriented along the [111] direction. It is also shown that single-band effective mass theory could not reproduce all the band state wave functions presented in this work.
Pulsed laser deposition of SrRuO3 thin-films: The role of the pulse repetition rate
Authors: Schraknepper H. , Bäumer C. , Gunkel F. , Dittmann R. , De Souza R. A.
Published: December 2016

SrRuO3 thin-films were deposited with different pulse repetition rates, fdep, epitaxially on vicinal SrTiO3 substrates by means of pulsed laser deposition. The measurement of several physical properties (e.g., composition by means of X-ray photoelectron spectroscopy, the out-of-plane lattice parameter, the electric conductivity, and the Curie temperature) consistently reveals that an increase in laser repetition rate results in an increase in ruthenium deficiency in the films. By the same token, it is shown that when using low repetition rates, approaching a nearly stoichiometric cation ratio in SrRuO3 becomes feasible. Based on these results, we propose a mechanism to explain the widely observed Ru deficiency of SrRuO3 thin-films. Our findings demand these theoretical considerations to be based on kinetic rather than widely employed thermodynamic arguments.
Theoretical investigations of the interfacial sliding and buckling of graphene on a flexible substrate
Authors: Cui Zhen , Guo Jian-Gang
Published: December 2016

Two interfacial failure modes, shear sliding and buckling, of graphene on a flexible substrate subjected to uniaxial compression are investigated. The shear sliding starts at the edge region, and buckling starts at the middle region of graphene. Using shear-lag cohesive zone models and finite element (FE) simulations, the critical strain and maximum strain of graphene are predicted for the interfacial sliding failure. Then, the critical strain for the onset of buckling is derived via the theory of continuum mechanics with the van der Waals (vdW) interaction between graphene and the substrate surface taken into consideration. By comparison of the two critical failure strains and maximum strain of graphene, it is found that there exists a critical length of graphene. As the graphene length is larger than it, interfacial failure goes through four stages of development with increasing loading, including sliding and buckling. Conversely, the buckling of graphene will not occur. Finally, the influence of the interfacial adhesion energy and geometric size of graphene on the critical strains for interfacial sliding and buckling are discussed.
Temperature effect on the structural stabilities and electronic properties of X22H28 (X=C, Si and Ge) nanocrystals: A first-principles study
Authors: Deng Xiao-Lin , Zhao Yu-Jun , Wang Ya-Ting , Liao Ji-Hai , Yang Xiao-Bao
Published: December 2016

Based on ab initio molecular dynamic simulations, we have theoretically investigated the structural stabilities and electronic properties of X22H28 (X=C, Si, and Ge) nanocrystals, as a function of temperature with consideration of vibrational entropy effects. To compare the relative stabilities of X22H28 isomers, the vibration free energies are obtained according to the calculated phonon spectrum, where the typical modes are shown to be dominant to the structural stabilities. In addition, there is a significant gap reduction as the temperature increases from 0 K to 300 K, where the decrements are 0.2 /0.5 /0.6eV for C/Si/Ge nanocrystals, respectively. The dependence of energy gap on the variance of bond length is also analyzed according to the corresponding atomic attributions to the HOMO and LUMO levels.
Coastal amplification of supply and transport (CAST): a new hypothesis about the persistence of Calanus finmarchicus in the Gulf of Maine
Authors: Ji Rubao , Feng Zhixuan , Jones Benjamin T. , Thompson Cameron , Chen Changsheng , Record Nicholas R. , Runge Jeffrey A.
Published: December 2016

The lipid-rich calanoid copepod, Calanus finmarchicus, plays a critical role in the pelagic food web of the western North Atlantic and particularly in the Gulf of Maine ecosystem. Deep basins along the continental shelf harbour high abundance of diapausing C. finmarchicus during the summer and fall. In Wilkinson Basin in the western Gulf of Maine, C. finmarchicus has persisted in large concentrations despite recent significant warming that could potentially threaten the existence of the population in this region. Identifying the major source of diapausing individuals is critical to the understanding of mechanisms that allow population persistence. In this study, Lagrangian tracking experiments using an individual-based copepod life cycle model and simulation of environmental conditions during an exceptionally warm year (2012) suggest that coastal waters are the major upstream source for individuals entering dormancy in Wilkinson Basin over summertime, although pathways and distribution patterns vary with the release timing of particles. Both model results and observation data support the Coastal Amplification of Supply and Transport (CAST) hypothesis as an explanation for the persistence of C. finmarchicus population in the western Gulf of Maine. The mechanism involves the coastal amplification of supply (spring reproduction/summer growth in the food-rich coastal region) and transport to the receiving Wilkinson Basin that is capable of harbouring the diapausing stock.
The effect of obesity, weight gain, and weight loss on asthma inception and control
Authors: Forno Erick , Celedón Juan C.
Published: December 2016

Purpose of review

There is ample and growing evidence that obesity increases the risk of asthma and morbidity from asthma. Here, we review recent clinical evidence supporting a causal link between obesity and asthma, and the mechanisms that may lead to ‘obese asthma’.

Recent findings

Although in some children obesity and asthma simply co-occur, those with ‘obese asthma’ have increased asthma severity, lower quality of life, and reduced medication response. Underlying mechanistic pathways may include anatomical changes of the airways such as obstruction and dysanapsis, systemic inflammation, production of adipokines, impaired glucose–insulin metabolism, altered nutrient levels, genetic and epigenetic changes, and alterations in the airway and/or gut microbiome. A few small studies have shown that weight loss interventions may lead to improvements in asthma outcomes, but thus far research on therapeutic interventions for these children has been limited.

Obesity increases the risk of asthma – and worsens asthma severity or control – via multiple mechanisms. ‘Obese asthma’ is a complex, multifactorial phenotype in children. Obesity and its complications must be managed as part of the treatment of asthma in obese children.
Intentional Intra-arterial Injection of Heroin: A Case Report
Authors: Suzuki Joji , Valenti Erin S.
Published: December 2016

Intravenous injection of drugs is associated with a host of medical complications, notably soft-tissue infections. On the contrary, intra-arterial injections of drugs have also been reported, largely restricted to inadvertent injections. Here we describe a patient who engaged in repeated intra-arterial injections of heroin when she exhausted most of her venous access, and presented acutely with a radial artery occlusion requiring thrombolytic therapy. Clinicians should have a high index of suspicion for intra-arterial injection in injection drug users who present with limb pain, ischemia, and motor/sensory deficits. Given the reluctance patients may have in discussing their injection practices, clinicians should proactively discuss and counsel patients about safe injection practices and the dangers of intra-arterial injections.
Perioperative and Anesthetic Considerations for Neurosurgical Laser Interstitial Thermal Therapy Ablations
Authors: Jimenez-Ruiz Federico , Arnold Benjamin , Tatsui Claudio E. , Cata Juan P.
Published: December 2016

Objective:

To describe the anesthetic considerations in patients undergoing laser interstitial thermal therapy (LITT) for neurosurgical procedures.

Background:

LITT for neurosurgical procedures is being increasingly used in a variety of central nervous system diseases. Several studies have demonstrated promising results including a shorter hospital stay. Given the rising trend for the use of LITT, anesthesiologists need to be familiar with the anesthetic considerations to provide care for patients undergoing these types of procedures.

Materials and Methods:

PubMed was searched in April 2016 using different combinations of the following MeSH terms: “Central nervous System,” “laser therapy,” “Ablation Techniques,” “Anesthesia,” and “Spinal Cord Neoplasms.” A total of 54 relevant manuscripts were included in this review article.

Conclusions:

LITT is a promising therapeutic approach for multiple central nervous system disorders. Anesthesiologists must be familiar with the anesthetic considerations and the technical aspects of the procedure when providing care for patients undergoing LITT. The literature is scarce on the impact of different anesthesia and analgesia techniques on clinical outcomes. Therefore, studies comparing different anesthetic regimens and the impact on outcomes are needed to make relevant recommendations on the anesthesia care of these patients.
Innovations in Functional Neurosurgery and Anesthetic Implications
Authors: Dunn Lauren K. , Durieux Marcel E. , Elias W. Jeffrey , Nemergut Edward C. , Naik Bhiken I.
Published: December 2016

Functional neurosurgery has undergone rapid growth over the last few years fueled by advances in imaging technology and novel treatment modalities. These advances have led to new surgical treatments using minimally invasive and precise techniques for conditions such as Parkinson’s disease, essential tremor, epilepsy, and psychiatric disorders. Understanding the goals and technological issues of these procedures is imperative for the anesthesiologist to ensure safe management of patients presenting for functional neurosurgical procedures. In this review, we discuss the advances in neurosurgical techniques for deep brain stimulation, focused ultrasound and minimally invasive laser-based treatment of refractory epilepsy and provide a guideline for anesthesiologists caring for patients undergoing these procedures.
Management of early onset scoliosis
Authors: Johari Ashok N. , Maheshwari Shalin K. , Nemade Amit , Maheshwari Ratna
Published: December 2016

The treatment of early onset scoliosis has improved with recent advances in the last ten years. The purpose of this review was to provide the reader with a brief description of the new therapeutic modalities, their indications, and outcomes. In children with a progressive curve that is less than 60 degrees and in whom no surgical treatment has been performed, derotational bracing may be considered; however, the role of bracing is mostly limited to maintenance of correction after surgery. Dual growing rods appear to afford better correction initially, maintenance of correction, increased T1-S1 length, and decreased implant-related issues. However, complication rates remain problematic with younger children, children with neuromuscular disorders or syndromes, and children with a greater degree of curvature having the highest rates. Patient heterogeneity and short follow-up after surgery largely explain the subjectivity of surgical decisions that are not reproducible.
Current concepts in the management of spondylolisthesis
Authors: Chaddha Ram , Keny Swapnil M.
Published: December 2016

This article reviews the current concepts in the diagnosis and management of spondylolisthesis and presents the views of experts on this enigmatic and challenging deformity. It examines the concepts of anatomical indices in spondylolisthesis and compares the outcomes of various recent studies for the diagnosis and management of spondylolisthesis.
Spinal Anesthesia Improves Early Pain Levels After Surgical Treatment of Tibial Plateau Fractures
Authors: Manoli Arthur , Atchabahian Arthur , Davidovitch Roy I. , Egol Kenneth A.
Published: December 2016

Objectives:

To determine the effect of spinal anesthesia (SA) on short-term outcomes when compared with general anesthesia in operatively managed tibial plateau fractures.

Design:

This is an institutional review board–approved retrospective review of prospectively collected data.

Setting:

Two level-1 trauma centers.

Participants:

One hundred twelve patients with a surgically managed tibial plateau fracture were identified within a registry of patients.

Intervention:

Of these, 29 (25.9%) received SA and 83 (74.1%) received general anesthesia in a nonrandomized fashion.

Main Outcome Measures:

Short Musculoskeletal Functional Assessment scores, pain levels, knee range of motion, complications, and reoperations.

Results:

SA was found to be a predictor of lower pain scores at 3 months (odds ratio, 0.32; 95% confidence interval, 0.12–0.95; P = 0.039) but not at 6 months (P = 0.266) or the latest follow-up (P = 0.056). In the multivariate Short Musculoskeletal Functional Assessment model, although anesthesia type was not found to be a statistically significant predictor, other predictors were identified. Anesthesia type was not a predictor of complications or reoperations. In the univariate analysis, SA was associated with an increased knee range of motion at 3 months (121 vs. 111 degrees; P = 0.048) but not at 6 months (P = 0.31) or the latest follow-up (P = 0.053).

Conclusion:

In patients who undergo surgical management of a tibial plateau fracture, the use of SA is associated with decreased pain levels in the early postoperative period; however, there was no effect on functional assessment scores.

Level of Evidence:

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
Is There Value in Having Radiology Provide a Second Reading in Pediatric Orthopaedic Clinic?
Authors: Natarajan Vivek , Bosch Patrick , Dede Ozgur , Deeney Vincent , Mendelson Stephen , Ward Timothy , Brooks Maria , Kenkre Tanya , Roach James
Published: December 2016

Background:

The Joint Commission on Accreditation of Healthcare Organizations specifically mandates the dual interpretation of musculoskeletal radiographs by a radiologist in addition to the orthopaedist in all hospital-based orthopaedic clinics. Previous studies have questioned the utility of this practice. The purpose of this study was to further investigate the clinical significance of having the radiologist provide a second interpretation in a hospital-based pediatric orthopaedic clinic.

Methods:

A retrospective review was performed of all patients who had plain radiographs obtained in the pediatric orthopaedic clinic at an academic children’s hospital over a 4-month period. For each radiographic series, the orthopaedist’s note and the radiology interpretation were reviewed and a determination was made of whether the radiology read provided new clinically useful information and/or a new diagnosis, whether it recommended further imaging, or if it missed a diagnosis that was reflected in the orthopaedist’s note. The hospital charges associated with the radiology read for each study were also quantified.

Results:

The charts of 1570 consecutive clinic patients who were seen in the pediatric orthopaedic clinic from January to April, 2012 were reviewed. There were 2509 radiographic studies performed, of which 2264 had both a documented orthopaedist’s note and radiologist’s read. The radiologist’s interpretation added new, clinically important information in 1.0% (23/2264) of these studies. In 1.7% (38/2264) of the studies, it was determined that the radiologist missed the diagnosis or clinically important information that could affect treatment. The total amount of the professional fees charged for the radiologists’ interpretations was $87,362. On average, the hospital charges for each occurrence in which the radiologist’s read provided an additional diagnosis or clinically important information beyond the orthopaedist’s note were $3798.

Conclusions:

The results of this study suggest that eliminating the requirement to have the radiologist interpret radiographs in the pediatric orthopaedic clinic would have few clinical consequences.

Level of Evidence:

Level III—This is a diagnostic retrospective cohort study.
Benign Osteolytic Lesions in Children With Previously Normal Radiographs
Authors: Tan Emily , T. Mehlman Charles , Baker Michael
Published: December 2016

Background:

Benign bone tumors are common in children and are usually diagnosed incidentally or after pathologic fractures. However, case reports of children with lytic lesions with previously normal radiographs are rare. This series presents several such cases.

Methods:

This was a retrospective case series of 8 benign osteolytic lesions in 8 pediatric patients (5 female and 3 males). All have previous radiographs of the effected extremity showing no pathology. All participants were at a single institution.

Results:

Eight cases were identified with 2 aneurysmal bone cysts and 6 nonossifying fibromas. Average age at discovery was 10.75 years old. The range of time between normal and pathologic radiographs was from 2.5 to 7.25 years. Both cases of aneurysmal bone cysts were histologically confirmed and treated with curettage and grafting with one recurrence. One of 6 nonossifying fibromas was treated surgically with the remainder treated with casting for pathologic fractures or observation for incidentally identified lesions.

Conclusions:

Benign osteolytic lesions such as aneurysmal bone cysts and nonossifying fibromas can arise in a short time period. The average time between normal and pathologic radiographs was 4.6 years. Prelesion radiographs were obtained to evaluate traumas and leg length discrepancies.

Clinical Relevance:

Radiographs taken before diagnosis in children with osseous lesions are rare, but likely under recognized. Further studies of such instances in larger databases may provide a noninvasive means to reach diagnostic or etiologic conclusions.
Orthopaedic Surgery in Dystonic Cerebral Palsy
Authors: Blumetti Francesco C. , Wu Jenny Chia Ning , Barzi Federica , Axt Matthias W. , Waugh Mary-Clare , Selber Paulo
Published: December 2016

Background:

Outcomes after orthopaedic interventions in patients with dystonic cerebral palsy (DCP) are historically regarded as unpredictable. This study aims to evaluate the overall outcome of orthopaedic surgery in children with DCP.

Method:

Children with DCP who underwent lower limb orthopaedic surgery with a minimum follow-up of 12 months were included. Data collected included age at time of surgery, surgical procedures performed, Gross Motor Function Classification System (GMFCS) level, and Barry Albright Dystonia Scale (BADS) score. The cohort was divided into 2 groups. Group 1 (GMFCS levels I to III), mean age 12 years 7 months and group 2 (GMFCS levels IV to V), mean age 10 years 7 months. Group 1 had surgery aimed at deformity correction to improve gait and mobility, and group 2 for the management or prevention of hip displacement. Outcome measures analyzed were: the incidence of unpredictable results related to surgery and early recurrence of deformity in both groups. Functional mobility scale scores were evaluated for group 1 and hip migration percentage for group 2. Linear mixed models were used to take into account repeated measures over time and correlations between measurements from the same patient.

Results:

Group 1 (n=18); had low BADS scores and were considered to have mild dystonia. Three children experienced unpredictable results, 2 had early recurrence of deformity, 3 had a decline, and 1 child improved in the functional mobility scale.

Group 2 (n=19); had high BADS scores and were considered to have moderate to severe dystonia. Nine surgical events involved bony procedures and 15 were soft tissue surgery only. One surgical event lead to unpredictable results and 2 children had early recurrence of deformity. Postoperatively, a linear trend of increasing migration percentage [0.49% (95% confidence interval, 0.23-0.74; P=0.0002)] was seen up to 21 months. There was no significant change after 21 months [−0.08% (95% confidence interval, −0.24 to +0.041; P=0.18)].

Conclusions:

This study suggests that unpredictable results and early recurrence of deformity following orthopaedic surgery in children with DCP are not as common as previously regarded. Furthermore, functional mobility and hip morphology can be improved.

Level of Evidence:

Level IV—this is a case-series.
Vitamin D Deficiency: The Missing Etiological Factor in the Development of Juvenile Osteochondrosis Dissecans?
Authors: Maier Gerrit S. , Lazovic Djordje , Maus Uwe , Roth Klaus E. , Horas Konstantin , Seeger Jörn B.
Published: December 2016

Background:

Vitamin D deficiency can result in rickets and hypocalcemia during infant and childhood growth. There is an increasing interest in the role of vitamin D with regards to childhood bone health. Osteochondrosis dissecans (OD) is a common disease affecting different joints. To date, the exact etiology of OD still remains unclear. The aim of this study was to evaluate a possible association of vitamin D deficiency and juvenile OD.

Methods:

A retrospective chart review of the years 2010 to 2015 of all orthopaedic patients with an initial diagnosis of juvenile OD admitted to undergo operative treatment of the OD was performed. Patient demographics, medical history, information on sports activity (if available) and serum vitamin D (25-OH-D) level on admission date were obtained. For statistical comparison, we measured baseline prevalence of vitamin D insufficiency in age-matched orthopaedic patients presenting at the department of pediatric orthopaedics.

Results:

A total of 80 patients were included in this study. Overall, 97.5% (n=78) of tested patients in the OD group had serum vitamin D levels below the recommended threshold of 30 ng/mL (mean value of 10.1 ng/mL (±6.7 ng/mL)). Over 60% (n=49) were vitamin D deficient, 29 patients (37%) showed serum levels below 10 ng/mL corresponding to a severe vitamin D deficiency. Of note, only 2 patients (2.5%) reached serum vitamin D levels above the recommended threshold of 30 ng/mL. No statistical difference was found in respect to sports activity level before onset of the symptoms (P=0.09). Statistical analysis found a significant difference in vitamin D levels between patients with OD and patients without an OD (P=0.026).

Conclusions:

We found an unexpected high prevalence of vitamin D deficiency in juveniles diagnosed with OD presenting with significant lower mean 25-OH-D level compared with a control group. These results suggest that vitamin D deficiency is potentially associated with the development of OD. Thus, vitamin D deficiency might be an important cofactor in the multifactorial development of juvenile OD. For this reason, supplementation of vitamin D might not only be a potential additional therapy but also be a possible preventative factor in patients with juvenile OD. However, future prospective studies are needed to confirm this preliminary data.

Level of Evidence:

Level III—this is a case-control study.
Percutaneous Hamstring Lengthening Surgery is as Effective as Open Lengthening in Children With Cerebral Palsy
Authors: Nazareth Alexander , Rethlefsen Susan , Sousa Ted C. , Mueske Nicole M. , Wren Tishya A.L. , Kay Robert M.
Published: December 2016

Background:

Surgical lengthening of the hamstrings is often performed to correct crouch gait in children with cerebral palsy (CP). Previous studies have demonstrated the effectiveness of open hamstring lengthening (oHSL) in improving knee extension static and dynamic range of motion; however, literature regarding percutaneous hamstring lengthening (pHSL) is limited. The purpose of this study was to investigate the effect of open versus pHSL for improving crouch gait and knee function in children with CP.

Methods:

This retrospective cohort study included 87 ambulatory children with CP who underwent HLS surgery with both preoperative and postoperative gait analysis (mean time, 29.4±19.9 mo after surgery) testing between 1997 and 2015. In total, 65 patients underwent oHLS surgery (mean age, 8.5±2.5 y) and 22 patients underwent pHSL surgery (mean age, 8.3±2.3 y). Lower extremity three-dimensional kinematic data were collected while subjects walked at a self-selected speed. Outcome variables for operative limbs were compared within and between groups using t tests, χ2 tests, and multiple regression analysis.

Results:

Significant postoperative decreases in knee flexion at initial contact were seen for both open (Δ12.7±13.4 degrees; P<0.001) and percutaneous (Δ19.1±13.1 degrees; P<0.001) groups. Increased postoperative maximum knee extension in stance was found for both open (Δ8.2±16.8 degrees; P=0.001) and percutaneous (Δ14.4±16.5 degrees; P=0.001) groups. No significant differences between open and percutaneous groups were found when comparing postoperative changes in kinematic variables between groups after adjusting for covariates. Postoperative changes in static range of motion were similar between lengthening groups.

Conclusions:

pHSL is as effective as open lengthening in improving stance phase knee kinematics during gait in children with CP. This is the first study to compare the kinematic effects of open versus pHSL in the pediatric population. Percutaneous lengthening is tolerated well by patients, and as it allows for rapid rehabilitation it may be preferable to the open procedure.

Level of Evidence:

Level III—retrospective comparative study.
Neoadjuvant approach for nonsmall cell lung cancer: overview of the current issues
Authors: Francolini Giulio , Ferrari Katia , Scotti Vieri
Published: December 2016

Purpose of review

Despite the large numbers of studies, role of neoadjuvant chemotherapy and neoadjuvant chemoradiotherapy is debated. This approach would increase resectability in locally advanced patients, and improve surgical outcome in resectable patients. Thus, an overview of recent literature is relevant to highlight the current issues.

Recent findings

Literature in the previous year mainly focused on overall treatment strategy, radiotherapy technique, role of radiological response and metabolic imaging, and biological agents in this setting.

Current data suggest that neoadjuvant chemotherapy is beneficial if compared with surgery alone or definitive chemoradiotherapy. Benefit of radiotherapy addition in this setting is not clear, especially in patients undergoing pneumonectomy. Hypofractionated regimens and dose escalation protocols should be considered for further investigation. Response evaluation with radiologic and metabolic assessment is prognostic for survival outcome; its usefulness as a selection tool for adaptive strategies has been investigated recently. More robust data on biological agents and immunological agents in this setting are needed; further investigation on predictive biomarker is suggested.
Evaluation of a Novel Communication Application From Nurses’ Perspectives
Authors: Koszalinski Rebecca S. , Tappen Ruth M. , Melhuish Tracey , Grumme Valarie
Published: December 2016

The purpose of this article is to report usability of a computer application, Speak for Myself, from nurses’ perspectives. This was a one-group exploratory survey. Nurses included patients in the study who were older than 18 years, could write and speak English, were unable to verbalize needs for any reason, and had a specified sedation-agitation scale (−1 to +1). Patients were excluded if they were younger than 18, could not write and/or speak English, or had a Richmond Agitation-Sedation Scale score exceeding −1 to +1. Twelve RNs from various ICUs in two hospitals in South Florida participated in the study. A person who was a supervisor or clinical specialist was chosen in each participating unit and at each hospital for recruitment of patient participants. Five nurses (41.6%) stated their patients were able to communicate better with the use of Speak for Myself, and all 12 nurses (100%) indicated they would use Speak for Myself again. Suggestions for further development of Speak for Myself were offered from the nurses. Limitations include a small sample in South Florida. The results of this and previous studies about Speak for Myself will be used in further development and testing of the computer application.
A Review of Treatment for Breast Cancer-Related Lymphedema
Authors: Smile Timothy D. , Tendulkar Rahul , Schwarz Graham , Arthur Douglas , Grobmyer Stephen , Valente Stephanie , Vicini Frank , Shah Chirag
Published: December 2016

Objectives:

Breast cancer–related lymphedema (BCRL) represents a major complication of breast cancer treatment, impacting the quality of life for breast cancer survivors that develop it. The purpose of this review is to evaluate the literature surrounding BCRL treatment modalities to guide clinicians regarding risk-stratified treatment options.

Methods:

A review of studies over a 10-year period (January 2006 to February 2016) was performed. Noninvasive strategies evaluated included compression therapy, manual lymphatic drainage, and complex decongestive therapy (CDT). Invasive modalities evaluated included liposuction and lymphatic bypass/lymph node transfer (LNT). Our search yielded 149 initial results with 45 studies included.

Results:

A number of prospective studies have found that CDT is associated with volume reduction in the affected limb as well as improved quality of life, particularly in patients with early stage BCRL. With regards to invasive treatment options, data support that lymphatic bypass and LNT are associated with symptomatic and physiologic improvements, particularly in patients with more advanced BCRL. In addition, a small number of studies suggest that liposuction may be an efficacious and safe treatment for moderate to severe BCRL.

Conclusions:

CDT is an effective treatment modality for early stage BCRL. For more advanced BCRL, LNT has demonstrated efficacy. Further study is required with respect to comparing BCRL treatment modalities.