bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on correlation between wind turbine performance and ice accretion along a blade tip airfoil using CFD
Authors: Han Woobeom , Kim Jonghwa , Kim Bumsuk
Published: April 2018

In cold-region environments characterized by high wind speeds, low external air temperatures, and supercooled water droplets, wind turbines frequently experience ice formation along the leading edge of the blade tip, which has a higher angular velocity. This ice formation directly and negatively affects the wind turbine's power performance. As such, a clear understanding of the relationship between ice formation and wind turbine power performance is required. In this study, we used computational fluid dynamics (CFD) simulation methods based on the dispersed multiphase (DMP) droplet model to predict ice formation along a blade tip airfoil's leading edge. To validate the ice formation model, the CFD simulation results were compared with the previously published wind tunnel testing results. Following validation, the model was used to predict the ice formation along the leading edge of the National Advisory Committee for Aeronautics (NACA) 64-618 airfoil and estimate its aerodynamic performance under variable external environmental conditions. Steady power calculations for the National Renewable Energy Laboratory's (NREL) 5-MW wind turbine was performed using the BLADED software. The aerodynamic performance of the NACA 64-618 airfoil following ice formation and the power performance of the NREL 5-MW wind turbine were subsequently correlated. The results indicated that ice formation on the blade tip airfoil's leading edge caused wind turbine power performance to decrease by approximately 8–29%.
A near one-dimensional indirectly driven implosion at convergence ratio 30
Authors: MacLaren S. A. , Masse L. P. , Czajka C. E. , Khan S. F. , Kyrala G. A. , Ma T. , Ralph J. E. , Salmonson J. D. , Bachmann B. , Benedetti L. R. , Bhandarkar S. D. , Bradley P. A. , Hatarik R. , Herrmann H. W. , Mariscal D. A. , Millot M. , Patel P. K. , Pino J. E. , Ratledge M. , Rice N. G. , Tipton R. E. , Tommasini R. , Yeamans C. B.
Published: April 2018

Inertial confinement fusion cryogenic-layered implosions at the National Ignition Facility, while successfully demonstrating self-heating due to alpha-particle deposition, have fallen short of the performance predicted by one-dimensional (1D) multi-physics implosion simulations. The current understanding, from experimental evidence as well as simulations, suggests that engineering features such as the capsule tent and fill tube, as well as time-dependent low-mode asymmetry, are to blame for the lack of agreement. A short series of experiments designed specifically to avoid these degradations to the implosion are described here in order to understand if, once they are removed, a high-convergence cryogenic-layered deuterium-tritium implosion can achieve the 1D simulated performance. The result is a cryogenic layered implosion, round at stagnation, that matches closely the performance predicted by 1D simulations. This agreement can then be exploited to examine the sensitivity of approximations in the model to the constraints imposed by the data.
Quantitative stress measurement of elastic deformation using mechanoluminescent sensor: An intensity ratio model
Authors: Cai Tao , Guo Songtao , Li Yongzeng , Peng Di , Zhao Xiaofeng , Liu Yingzheng
Published: April 2018

The mechanoluminescent (ML) sensor is a newly developed non-invasive technique for stress/strain measurement. However, its application has been mostly restricted to qualitative measurement due to the lack of a well-defined relationship between ML intensity and stress. To achieve accurate stress measurement, an intensity ratio model was proposed in this study to establish a quantitative relationship between the stress condition and its ML intensity in elastic deformation. To verify the proposed model, experiments were carried out on a ML measurement system using resin samples mixed with the sensor material SrAl2O4:Eu2+, Dy3+. The ML intensity ratio was found to be dependent on the applied stress and strain rate, and the relationship acquired from the experimental results agreed well with the proposed model. The current study provided a physical explanation for the relationship between ML intensity and its stress condition. The proposed model was applicable in various SrAl2O4:Eu2+, Dy3+-based ML measurement in elastic deformation, and could provide a useful reference for quantitative stress measurement using the ML sensor in general.
Non-invasive treatment efficacy evaluation for high-intensity focused ultrasound therapy using magnetically induced magnetoacoustic measurement
Authors: Guo Gepu , Wang Jiawei , Ma Qingyu , Tu Juan , Zhang Dong
Published: April 2018

Although the application of high intensity focused ultrasound (HIFU) has been demonstrated to be a non-invasive treatment technology for tumor therapy, the real-time temperature monitoring is still a key issue in the practical application. Based on the temperature-impedance relation, a fixed-point magnetically induced magnetoacoustic measurement technology of treatment efficacy evaluation for tissue thermocoagulation during HIFU therapy is developed with a sensitive indicator of critical temperature monitoring in this study. With the acoustic excitation of a focused transducer in the magnetoacoustic tomography with the magnetic induction system, the distributions of acoustic pressure, temperature, electrical conductivity, and acoustic source strength in the focal region are simulated, and the treatment time dependences of the peak amplitude and the corresponding amplitude derivative under various acoustic powers are also achieved. It is proved that the strength peak of acoustic sources is generated by tissue thermocoagulation with a sharp conductivity variation. The peak amplitude of the transducer collected magnetoacoustic signal increases accordingly along with the increase in the treatment time under a fixed acoustic power. When the temperature in the range with the radial and axial widths of about ±0.46 mm and ±2.2 mm reaches 69 °C, an obvious peak of the amplitude derivative can be achieved and used as a sensitive indicator of the critical status of treatment efficacy. The favorable results prove the feasibility of real-time non-invasive temperature monitoring and treatment efficacy evaluation for HIFU ablation using the magnetically induced magnetoacoustic measurement, and might provide a new strategy for accurate dose control during HIFU therapy.
Van der Waals interaction between perhalogenated ethylene and rare gas: A rotational study of chlorotrifluorethylene-argon
Authors: Zheng Yang , Li Xiaolong , Jin Yan , Feng Gang , Xia Zhining , Gou Qian
Published: April 2018

The rotational spectra of two isotopologues have been recorded and interpreted for the van der Waals complex chlorotrifluoroethylene-argon, by using pulsed jet Fourier transform microwave technique. Argon locates out of the ethylene plane, in the FCCF cavity of chlorotrifluoroethylene. The preference of the CFCl side over CF2 can be attributed to the presence of “π-hole” over the double bond in chlorotrifluoroethylene. Non-covalent interaction analysis indicated that the van der Waals interaction occurs between argon and two sites of chlorotrifluoroethylene (the π-system and the F atom of the CFCl top). The steric effect between Ar and the C—Cl bond repulses the Ar atom toward the C—F side.
Laboratory space physics: Investigating the physics of space plasmas in the laboratory
Authors: Howes Gregory G.
Published: April 2018

Laboratory experiments provide a valuable complement to explore the fundamental physics of space plasmas without the limitations inherent to spacecraft measurements. Specifically, experiments overcome the restriction that spacecraft measurements are made at only one (or a few) points in space, enable greater control of the plasma conditions and applied perturbations, can be reproducible, and are orders of magnitude less expensive than launching spacecraft. Here, I highlight key open questions about the physics of space plasmas and identify the aspects of these problems that can potentially be tackled in laboratory experiments. Several past successes in laboratory space physics provide concrete examples of how complementary experiments can contribute to our understanding of physical processes at play in the solar corona, solar wind, planetary magnetospheres, and the outer boundary of the heliosphere. I present developments on the horizon of laboratory space physics, identifying velocity space as a key new frontier, highlighting new and enhanced experimental facilities, and showcasing anticipated developments to produce improved diagnostics and innovative analysis methods. A strategy for future laboratory space physics investigations will be outlined, with explicit connections to specific fundamental plasma phenomena of interest.
A universal formula for the field enhancement factor
Authors: Biswas Debabrata
Published: April 2018

The field enhancement factor (FEF) is an important quantity in field emission calculations since the tunneling electron current depends very sensitively on its magnitude. The exact dependence of FEF on the emitter height h, the radius of curvature at the apex Ra, as well as the shape of the emitter base are still largely unknown. In this work, a universal formula for the field enhancement factor is derived for a single emitter. It depends on the ratio h/Ra and has the form γa=(2h/Ra)/[α1ln(4h/Ra)−α2], where α1 and α2 depend on the charge distribution on the emitter. Numerical results show that a simpler form γa=(2h/Ra)/[ln(4h/Ra)−α] is equally valid with α depending on the emitter-base. Thus, for the hyperboloid, conical, and ellipsoid emitters, the value of α is 0, 0.88, and 2, while for the cylindrical base, α ≃ 2.6.
Optimal scheduling of distributed energy resources and responsive loads in islanded microgrids considering voltage and frequency security constraints
Authors: Vahedipour-Dahraie Mostafa , Reza Najafi Hamid , Anvari-Moghaddam Amjad , Guerrero Josep M.
Published: April 2018

Low inertia of distributed energy resources (DERs), high penetration levels of renewable energy sources (RESs), and load demand variations put the islanded microgrids' (MGs) security at the risk of instability. This paper proposes a two-stage stochastic model for coordination of DERs and responsive loads in islanded MGs with regard to voltage and frequency security constraints. Based on the proposed model, scheduling of the controllable units in both supply and demand sides is done in a way not only to maximize the expected profit of the MG operator (MGO) but also to minimize the energy payments of customers under the premise of security and stability of MG. An AC optimal power flow procedure is also used to study the operating condition of the system under uncertainties and to guarantee acceptable nodal voltages and system frequency under different scenarios. The proposed stochastic optimization model is then applied to a typical autonomous MG, and its effectiveness is demonstrated through different scenarios under uncertainties in load consumption and renewable energy resource (RES) productions. Simulation results demonstrate that customers' participation in DR programs has a significant effect on the system's performance in terms of voltage and frequency stability. Moreover, optimal coordination of DERs and responsive loads can increase the expected profit of MGO significantly. The effectiveness of the proposed scheduling approach is verified on an islanded MG test system over a 24-h period.
Exact integration of the unsteady incompressible Navier-Stokes equations, gauge criteria, and applications
Authors: Scholle M. , Gaskell P. H. , Marner F.
Published: April 2018

An exact first integral of the full, unsteady, incompressible Navier-Stokes equations is achieved in its most general form via the introduction of a tensor potential and parallels drawn with Maxwell’s theory. Subsequent to this gauge freedoms are explored, showing that when used astutely they lead to a favourable reduction in the complexity of the associated equation set and number of unknowns, following which the inviscid limit case is discussed. Finally, it is shown how a change in gauge criteria enables a variational principle for steady viscous flow to be constructed having a self-adjoint form. Use of the new formulation is demonstrated, for different gauge variants of the first integral as the starting point, through the solution of a hierarchy of classical three-dimensional flow problems, two of which are tractable analytically, the third being solved numerically. In all cases the results obtained are found to be in excellent accord with corresponding solutions available in the open literature. Concurrently, the prescription of appropriate commonly occurring physical and necessary auxiliary boundary conditions, incorporating for completeness the derivation of a first integral of the dynamic boundary condition at a free surface, is established, together with how the general approach can be advantageously reformulated for application in solving unsteady flow problems with periodic boundaries.
Evaluating the economics of short-term partial mixed ration feeding decisions for dairy cows
Authors: Ho C. K. M. , Wales W. J. , Auldist M. J. , Malcolm B.
Published: April 2018

Recent research in Australia has measured the marginal milk production responses of cows grazing perennial-based pastures to supplements offered as a partial mixed ration (PMR). In the present study, the milk responses to PMR feeding developed under a restricted pasture allowance were used to examine the contribution to farm profit of decisions about short-term feeding (weekly, monthly). A short-term, or tactical, decision was considered to be one where the infrastructure and equipment needed to mix and feed out a formulated ration were already available. The decision was, therefore, the choice of whether to feed supplements as grain in the dairy at milking and forage in the paddock, or to feed the supplements as a mixed ration on a feed pad. Both of these options were assumed to exist for the farmer decision-maker, with the comparison of rations being based solely on the costs of supplement and milk income. The Control diet in the experiments comprised cereal grain fed in the dairy and pasture silage fed in the paddock, simulating a situation where pasture available for grazing was limiting. The PMR diet consisted of cereal grain, maize grain, maize silage and lucerne hay combined in a mixer wagon and fed on a feed pad. The PMR + canola diet was similar to the PMR diet, but included canola meal. The profitability of the diets for different amounts of supplement intake was compared by estimating the total income from milk produced minus the cost of the supplements. The results indicated that feeding the diet comprising PMR plus canola meal in early lactation contributed more to farm profit than did the Control diet of feeding grain in the dairy and forage in the paddock, or PMR feeding without canola meal, because of higher milk production. At a supplement intake of 12 kg DM/cow.day, the PMR + canola diet added AU$0.97/cow.day and AU$2.11/cow.day more to profit than the Control and PMR without canola meal diets, respectively. For a farm already equipped with a feed pad and mixer wagon, the benefits of feeding a mixed ration exceed the costs in early lactation. In late lactation, each diet made similar contributions to farm profit because of similar milk production.
Arbovirus infections of animals: congenital deformities, encephalitis, sudden death and blindness
Authors: Kirkland Peter D
Published: April 2018

Viruses from five different taxonomic families have been shown to be the cause of disease outbreaks in either domesticated or wild animals. These include viruses spread by both mosquitoes and biting midges from the genus Culicoides, especially C. brevitarsis. A number of arboviruses also present significant impediments to the international movement of live animals, semen and embryos.
Deficiencies in our understanding of the hydro-ecology of several native Australian fish: a rapid evidence synthesis
Authors: Miller Kimberly A. , Casas-Mulet Roser , de Little Siobhan C. , Stewardson Michael J. , Koster Wayne M. , Webb J. Angus
Published: April 2018

Environmental flows aim to mitigate the impacts of modification of riverine flow regimes by restoring components of the natural flow regime. Explicit evidence-based cause–effect relationships between flow regimes and fish responses are required for defensible flow recommendations. However, flow recommendations are typically based on expert opinion rather than a rigorous test of the available evidence. We used rapid evidence synthesis to systematically review the literature on responses of several native Australian fish to flow-related and other important environmental variables, and tested 13 explicit hypotheses. The hypotheses were related to the condition, reproduction and survival of pygmy perches, carp gudgeons, blackfish and flat-headed gudgeons. The evidence was insufficient to reach strong conclusions for all but three of our hypotheses. Late-spring high flows are associated with increased survival of pygmy perches and carp gudgeons, and exotic fish are associated with decreased survival of these fishes. The evidence that warmer spring water temperatures enhance their reproduction was inconsistent. The dearth of evidence to support or refute most hypotheses points to substantial gaps in our understanding of hydro-ecology of these native Australian fish, highlighting the need for targeted monitoring and research to further understand key flow relationships for these fish species.
Partisan follow-ups
Authors: Fukushima Tatsuya
Published: April 2018

This study examines patterns of demand statement distribution in newspaper editorials during the 2013 Japanese House of Councillors (i.e., Upper House) election in anticipation that their ideological slant will become salient in the skewed patterns of certain linguistic forms. Distribution patterns in this study contradict the predictions inferable from the ideological slant of newspapers. In particular, this study finds that a conservative newspaper distributes its demands equally at both sides of the political spectrum. However, this study finds that this newspaper frequently – and exclusively – employs partisan follow-ups (wherein a demand statement directed at all parties or candidates is followed by an example of concrete action/inaction by a certain party) in an implicit attempt to express its view in favor of the ruling coalition of conservative parties.
A Clash of Names: The Terminological Morass of a Toponym Class
Authors: Tent Jan , Blair David
Published: April 2018

There are place names all around the world formed by a combination of two elements, a specific and a generic, both of which refer to the same geographic feature type. A typical pattern is for an indigenous generic functioning as a specific to precede a matching introduced generic. For example: Ohio River < Iroquoian Ohio ‘Great River’ + River; and Lake Rotorua < Māori roto ‘lake’ + rua ‘two/second’ (‘Second Lake’) + Lake. Such toponyms, though not overall numerous, nevertheless occur often enough to warrant being recognized as a distinct class of place names. The literature provides no adequate or consistent term for this pattern: the various attempts clash with each other, and all fail to address the concept effectively. This article aims to address this situation.
Modulation of the secretory pathway by amino-acid starvation
Authors: van Leeuwen Wessel , van der Krift Felix , Rabouille Catherine
Published: April 2018

As a major anabolic pathway, the secretory pathway needs to adapt to the demands of the surrounding environment and responds to different exogenous signals and stimuli. In this context, the transport in the early secretory pathway from the endoplasmic reticulum (ER) to the Golgi apparatus appears particularly regulated. For instance, protein export from the ER is critically stimulated by growth factors. Conversely, nutrient starvation also modulates functions of the early secretory pathway in multiple ways. In this review, we focus on amino-acid starvation and how the function of the early secretory pathway is redirected to fuel autophagy, how the ER exit sites are remodeled into novel cytoprotective stress assemblies, and how secretion is modulated in vivo in starving organisms. With the increasingly exciting knowledge on mechanistic target of rapamycin complex 1 (mTORC1), the major nutrient sensor, it is also a good moment to establish how the modulation of the secretory pathway by amino-acid restriction intersects with this major signaling hub.
Quadrature rules from finite orthogonality relations for Bernstein-Szegö polynomials
Authors: van Diejen J. , Emsiz E.
Published: April 2018

We glue two families of Bernstein-Szegö polynomials to construct the eigenbasis of an associated finite-dimensional Jacobi matrix. This gives rise to finite orthogonality relations for this composite eigenbasis of Bernstein-Szegö polynomials. As an application, a number of Gauss-like quadrature rules are derived for the exact integration of rational functions with prescribed poles against the Chebyshev weight functions.
Remarks on the abelian convexity theorem
Authors: Biliotti Leonardo , Ghigi Alessandro
Published: April 2018

This paper contains some observations on abelian convexity theorems. Convexity along an orbit is established in a very general setting using Kempf–Ness functions. This is applied to give short proofs of the Atiyah–Guillemin–Sternberg theorem and of abelian convexity for the gradient map in the case of a real analytic submanifold of complex projective space. Finally we give an application to the action on the probability measures.
Urine Antigen Detection as an Aid to Diagnose Invasive Aspergillosis
Authors: Marr Kieren A , Datta Kausik , Mehta Seema , Ostrander Darin B , Rock Michelle , Francis Jesse , Feldmesser Marta
Published: April 2018

Background

Establishing rapid diagnoses of invasive aspergillosis (IA) is a priority tests that detect galactomannan and β-d-glucan are available, but are technically cumbersome and rely on invasive sampling (blood or bronchoalveolar lavage).

Methods

We optimized a lateral flow dipstick assay using the galactofuranose-specific monoclonal antibody (mAb476), which recognizes urine antigens after Aspergillus fumigatus pulmonary infection in animals. Urine samples were obtained from a cohort of 78 subjects undergoing evaluation for suspected invasive fungal infections, and stored frozen until testing. Urine was processed by centrifugation through desalting columns and exposed to dipsticks. Reviewers blinded to clinical diagnoses graded results. Western blots were performed on urine samples from 2 subjects to characterize mAb476-reactive antigens.

Results

Per-patient sensitivity and specificity for diagnosis of proven or probable IA in the overall cohort was 80% (95% confidence interval [CI], 61.4%–92.3%) and 92% (95% CI, 74%–99%), respectively. In the subgroup with cancer, sensitivity was 89.5% (95% CI, 66.7%–98.7%) and specificity was 90.9% (95% CI, 58.7%–99.8%); among all others, sensitivity and specificity were 63.6% (95% CI, 30.8%–89.1%) and 92.9% (95% CI, 66.1%–99.8%), respectively. Eliminating lung transplant recipients with airway disease increased sensitivity in the noncancer cohort (85.7% [95% CI, 42.1%–99.6%]). Semiquantitative urine assay results correlated with serum galactomannan indices. Western blots demonstrated mAb476-reactive antigens in urine from cases, ranging between 26 kDa and 35 kDa in size.

Conclusions

Urine testing using mAb476 may be used as an aid to diagnose IA in high-risk patients.
The ups and downs of S. aureus nasal carriage
Authors: Jarrett Angela M , Cogan Nicholas G
Published: April 2018

Staphylococcus aureus infections are a growing concern worldwide due to the increasing number of strains that exhibit antibiotic resistance. Recent studies have indicated that some percentage of people carry the bacteria in the nasal cavity and therefore are at a higher risk of subsequent, and more serious, infections in other parts of the body. However, individuals carrying the infection can be classified as only intermittent carriers versus persistent carriers, being able to eliminate the bacteria and later colonized again. Using a model of bacterial colonization of the anterior nares, we investigate oscillatory patterns related to intermittent carriage of S. aureus. Following several studies using global sensitivity analysis techniques, various insights into the model’s behaviour were made including interacting effects of the bacteria’s growth rate and movement in the mucus, suggesting parameter connections associated with biofilm-like behaviour. Here the bacterial growth rate and bacterial movement are explicitly connected, leading to expanded oscillatory behaviour in the model. We suggest possible implications that this oscillatory behaviour can have on the definition of intermittent carriage and discuss differences in the bacterial virulence dependent upon individual host health. Furthermore, we show that connecting the bacterial growth and movement also expands the region of the parameter space for which the bacteria are able to survive and persist.
Tire Tracks and Integrable Curve Evolution
Authors: Bor Gil , Levi Mark , Perline Ron , Tabachnikov Sergei
Published: April 2018

We study a simple model of bicycle motion: a segment of fixed length in multi-dimensional Euclidean space, moving so that the velocity of the rear end is always aligned with the segment. If the front track is prescribed, the trajectory of the rear wheel is uniquely determined via a certain first order differential equation—the bicycle equation. The same model, in dimension two, describes another mechanical device, the hatchet planimeter. Here is a sampler of our results. We express the linearized flow of the bicycle equation in terms of the geometry of the rear track; in dimension three, for closed front and rear tracks, this is a version of the Berry phase formula. We show that in all dimensions a sufficiently long bicycle also serves as a planimeter: it measures, approximately, the area bivector defined by the closed front track. We prove that the bicycle equation also describes rolling, without slipping and twisting, of hyperbolic space along Euclidean space. We relate the bicycle problem with two completely integrable systems: the Ablowitz, Kaup, Newell, and Segur (AKNS) system and the vortex filament equation. We show that “bicycle correspondence” of space curves (front tracks sharing a common back track) is a special case of a Darboux transformation associated with the AKNS system. We show that the filament hierarchy, encoded as a single generating equation, describes a three-dimensional bike of imaginary length. We show that a series of examples of “ambiguous” closed bicycle curves (front tracks admitting self bicycle correspondence), found recently F. Wegner, are buckled rings, or solitons of the planar filament equation. As a case study, we give a detailed analysis of such curves, arising from bicycle correspondence with multiply traversed circles.
BRAF V600 Mutation and BRAF Kinase Inhibitors in Conjunction With Stereotactic Radiosurgery for Intracranial Melanoma Metastases: A Multicenter Retrospective Study
Authors: Mastorakos Panagiotis , Xu Zhiyuan , Yu James , Hess Judith , Qian Jack , Chatrath Ajay , Taylor Davis G , Kondziolka Douglas , Warnick Ronald , Chiang Veronica , Sheehan Jason
Published: April 2018

BACKGROUND

The BRAF mutation has been identified as a potent target for the treatment of metastatic melanoma and BRAF inhibitors (BRAFi) have demonstrated promising results against melanoma brain metastases (BM).

OBJECTIVE

To further investigate the effectiveness of this combined treatment regimen.

METHODS

In this multicenter retrospective cohort study, 198 patients with known BRAF mutation status and treated with stereotactic radiosurgery (SRS) between 2011 and 2015 were identified. Kaplan–Meier methodology and multivariate regression analysis was then used to compare survival based on each parameter.

RESULTS

The median survival after the diagnosis of BM in patients with BRAF mutation who received BRAFi was increased compared to survival in patients with wild-type BRAF (BRAF wt). In multivariate analysis, the BRAF mutation was an independent, positive prognostic factor with a hazard ratio of 0.59. BRAF mutated Patients who received BRAFi following SRS had improved survival compared to patients who received it before (P < .001) or concurrently (P = .007). PD-1 inhibitors improved survival, with more pronounced effect in patients not carrying the BRAF mutation. Among the patients who were treated with BRAFi, 10.4% developed intracerebral hematoma (ICH), in comparison to 3% of patients who were not treated with BRAFi (P = .03).

CONCLUSION

In the setting of widespread use of BRAFi, the presence of a BRAF mutation is an independent predictor of better prognosis in patients with melanoma BM that underwent SRS. The effect of BRAFi is optimal when treatment is initiated at least 1 wk following SRS. BRAFi may increase the frequency of asymptomatic ICH.
Pediatric Pituitary Adenomas: Early and Long-Term Surgical Outcome in a Series of 85 Consecutive Patients
Authors: Barzaghi Lina Raffaella , Losa Marco , Capitanio Jody Filippo , Albano Luigi , Weber Giovanna , Mortini Pietro
Published: April 2018

BACKGROUND

Young age has been reported as a negative prognostic factor for pituitary adenomas (PAs). They are very uncommon in children and adolescents; therefore, surgical outcomes are poorly described.

OBJECTIVE

To report results of microsurgical transsphenoidal approach (MTSA) in pediatric PAs.

METHODS

The study retrospectively analyzed 3040 PAs treated in our institute, according to the adenoma subtype and then divided into pediatric (≤18 yr) and adult groups (>18 yr). The average follow-up after surgery was 58 mo (n = 2906).

RESULTS

In the pediatric group, the majority of adenomas were hormone-secreting (89.5%) with a female sex prevalence (78%) in prolactinomas and nonfunctioning pituitary adenomas (NFPAs); the maximum diameter of growth hormone (GH)-secreting adenomas was greater (28.1 ± 4.1 mm) than in adults (18 ± 0.3 mm, P = .002). Surgical remission rate at 6 mo was similar in both groups for all adenoma subtypes: 72.1% and 76% in pediatric and adult Cushing's disease, 69.3% and 59.3% in prolactinomas, 55.6% and 61% in gigantism or acromegaly, 55.6% and 61.5% in NFPAs. Recurrences after remission occurred more frequently in pediatric GH-secreting adenomas compared to adults (40.0% vs 5.3%, P = .028) despite similar follow-up (38 ± 17 and 48.1 ± 2.2 mo, P = .7). Mortality was zero in the pediatric and 0.2% in the adult group (P = .7); major morbidity was 2.4% and 2.2%, respectively (P = .8).

CONCLUSION

MTSA was safe and effective in children and adolescents as in adults, with the only exception of higher recurrence rate in pediatric GH-secreting adenomas. No complications related to young age appeared.
Multicenter Investigation of Channel-Based Subcortical Trans-Sulcal Exoscopic Resection of Metastatic Brain Tumors: A Retrospective Case Series
Authors: Bakhsheshian Joshua , Strickland Ben A , Jackson Christina , Chaichana Kaisorn L , Young Ronald , Pradilla Gustavo , Chen Jefferson W , Bailes Julian , Zada Gabriel
Published: April 2018

BACKGROUND

Recent advancements have aimed to optimize visualization and minimize insult to healthy cortical and subcortical tissue through the use of tubular-based retractors.

OBJECTIVE

To investigate outcomes following resection of cerebral metastases using an integrated tubular retraction system with an exoscope and neuronavigation.

METHODS

A multicenter retrospective analysis of surgical outcomes in consecutive patients who underwent resection of a brain metastasis using a tubular retraction system and exoscope was performed.

RESULTS

Twenty-five patients were included, with a mean age of 61 yr (24-81 yr). Primary sources included lung (n = 13), breast (n = 3), renal cell (n = 3), and other (n = 6). Locations were frontal (n = 5), parietal (n = 8), cerebellar (n = 8), occipital (n = 3), and splenium (n = 1). Most lesions had a maximum diameter > 3.0 cm (n = 20) and a tumor depth > 4 cm (n = 14). Conversion to open (microscopic) craniotomy was not required in any case. Gross total resection was achieved in 20 cases (80.0%) and subtotal resection in 5 cases (20.0%). Median hospital stay was 2 d (1-12 d). All patients underwent postoperative radiation therapy. Perioperative complications developed in 1 patient (4.0%; hemiparesis and subsequent deep vein thrombosis). At 3-mo follow-up, no mortalities were observed, 19 patients (76.0%) demonstrated neurological improvements, 5 patients (20.0%) had a stable neurological exam, and 1 patient (4.0%) had a neurological decline.

CONCLUSION

Utilization of a channel-based, navigable retractor and exoscope is a feasible option for surgical resection of metastatic brain lesions.
Preoperative Patient Expectations of Postoperative Pain Are Associated with Moderate to Severe Acute Pain After VATS
Authors: Bayman Emine Ozgur , Parekh Kalpaj R , Keech John , Larson Nyle , Vander Weg Mark , Brennan Timothy J
Published: April 2018

Objective

The goal of this post hoc analysis of subjects from a prospective observational study was to identify the predictors of patients developing moderate to severe acute pain (mean numerical rating scale [NRS] ≥4, 0–10) during the first three days after video-assisted thoracoscopic surgery (VATS) from a comprehensive evaluation of demographic, psychosocial, and surgical factors.

Methods

Results from 82 patients who were enrolled one week before VATS and evaluated during the first three postoperative days are presented. The primary outcome variable of the current study was the presence of moderate to severe acute pain after VATS.

Results

Fifty-nine percent (95% confidence interval, 47–69%) of study subjects developed moderate to severe acute pain after VATS. Factors univariately associated with the presence of moderate to severe acute pain were greater average expected postoperative pain, greater pain to a suprathreshold cold stimulus, and longer durations of surgery and hospital stay (P < 0.05). When considered in the multiple logistic regression models, the patients’ preoperative average intensity of expected postoperative pain (NRS, 0–10) was the only measure associated with the moderate to severe acute pain. Average intensity of postoperative pain expected by patients when questioned preoperatively mediated the effect of reported intensity of pain to the suprathreshold cold stimulus for moderate to severe acute pain levels. Preoperative patient expectations had greater predictive value than other assessed variables including psychosocial factors such as catastrophizing or anxiety assessed one week before surgery.

Conclusions

None of the preoperative psychosocial measures were associated with the moderate to severe acute pain after VATS. Average expected postoperative pain was the only measure associated with the development of moderate to severe acute pain after VATS.
Benchmarking the Physical Therapist Academic Environment to Understand the Student Experience
Authors: Shields Richard K , Dudley-Javoroski Shauna , Sass Kelly J , Becker Marcie
Published: April 2018

Background

Identifying excellence in physical therapist academic environments is complicated by the lack of nationally available benchmarking data.

Objective

The objective of this study was to compare a physical therapist academic environment to another health care profession (medicine) academic environment using the Association of American Medical Colleges Graduation Questionnaire (GQ) survey.

Design

The design consisted of longitudinal benchmarking.

Methods

Between 2009 and 2017, the GQ was administered to graduates of a physical therapist education program (Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, The University of Iowa [PTRS]). Their ratings of the educational environment were compared to nationwide data for a peer health care profession (medicine) educational environment. Benchmarking to the GQ capitalizes on a large, psychometrically validated database of academic domains that may be broadly applicable to health care education. The GQ captures critical information about the student experience (eg, faculty professionalism, burnout, student mistreatment) that can be used to characterize the educational environment. This study hypothesized that the ratings provided by 9 consecutive cohorts of PTRS students (n = 316) would reveal educational environment differences from academic medical education.

Results

PTRS students reported significantly higher ratings of the educational emotional climate and student-faculty interactions than medical students. PTRS and medical students did not differ on ratings of empathy and tolerance for ambiguity. PTRS students reported significantly lower ratings of burnout than medical students. PTRS students descriptively reported observing greater faculty professionalism and experiencing less mistreatment than medical students.

Limitations

The generalizability of these findings to other physical therapist education environments has not been established.

Conclusions

Selected elements of the GQ survey revealed differences in the educational environments experienced by physical therapist students and medical students. All physical therapist academic programs should adopt a universal method to benchmark the educational environment to understand the student experience.
Open Reduction and Internal Fixation Versus Nonsurgical Treatment in Displaced Midshaft Clavicle Fractures: A Meta-Analysis
Authors: Ahmed Abdulaziz F. , Salameh Motasem , AlKhatib Nedal , Elmhiregh Aissam , Ahmed Ghalib O.
Published: April 2018

Objectives:

To compare open reduction and internal fixation (ORIF) and nonsurgical treatment outcomes in displaced midshaft clavicle fractures.

Data Sources:

PubMed, MEDLINE, EMBASE, Web of Science, Cochrane Library, and ClinicalTrials.gov were searched in September 2017.

Study Selection:

Inclusion criteria were randomized controlled trials reporting nonunion, shoulder functional outcomes, and subsequent surgery rates or pain scores. We excluded studies with patients younger than 16 years, maximum follow-up less than 9 months, and inaccessible full text.

Data Extraction:

Extracted data included the first author, publication year, number of patients, number of nonunions, Constant scores, disabilities of the arm, shoulder, and hand (DASH) scores, number of subsequent surgeries, and pain measured using the visual analog scale.

Data Synthesis:

The risk ratio of nonunion was 0.15 [95% confidence interval (CI), 0.08–0.31] in ORIF compared with that of nonsurgical treatment. Constant and DASH scores were significantly better in ORIF up to 6 months. The mean difference (MD) in DASH scores at 12 months was statistically insignificant in both treatments (MD, −4.19; 95% CI, −9.34 to 0.96). Constant scores remained significant in ORIF (MD, 4.39; 95% CI, 1.03–7.75). Subsequent surgeries and pain scores were similar in both treatments.

Conclusions:

Significant reduction in nonunions and favorable early functional outcomes are associated with ORIF. Nevertheless, late functional outcomes, subsequent surgeries, and pain scores are similar to those of nonsurgical treatment. Although patients treated with ORIF mainly had subsequent elective plate removals, nonsurgically treated patients had more surgical fixations for nonunions. As a result, there remains inconsistent evidence regarding the best treatment for displaced midshaft clavicle fractures.

Level of Evidence:

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
Development of the Canadian Nurse Informatics Competency Assessment Scale and Evaluation of Alberta's Registered Nurses' Self-perceived Informatics Competencies
Authors: Kleib Manal , Nagle Lynn
Published: April 2018

In today's digitally enabled healthcare environment, it is vitally important to assess Canadian nurses' competency in informatics. The researchers developed the Canadian Nurse Informatics Competency Assessment Scale, a 21-item comprehensive measure based on entry-to-practice informatics competencies for registered nurses, to facilitate assessment of informatics competencies and consequent, planning of formal and continuing education in informatics. The Canadian Nurse Informatics Competency Assessment Scale was used in a cross-sectional survey to determine self-perceived informatics competencies for Alberta's practicing nurses. Results from 2844 completed surveys showed that these nurses perceived their overall informatics competency as slightly above the mark of competent. Perceptions of competency were highest on foundational information and communication technology skills, slightly lower on competencies related to professional regulatory accountability and the use of information and communication technologies in the delivery of patient care, and lowest on information and knowledge management competencies. This study shed some light on priority areas for informatics education among practicing nurses in Alberta. Implications for nursing practice and research are discussed.
Cutaneous Metastasis of Adenocarcinoma of the Ampulla of Vater
Authors: Fernandez-Flores Angel , Cassarino David S.
Published: April 2018

Cutaneous metastases from an adenocarcinoma of the Ampulla of Vater are very rare, with only a few cases previously reported. We present here an additional case in a 57-year-old woman who complained of a painful growth on her frontal scalp that she had noticed 4 months earlier. Her medical history included an ampullary adenocarcinoma, which was diagnosed 4 years ago, excised through a Whipple procedure, and treated using chemotherapy and radiotherapy. The scalp biopsy showed a dermal and epidermotropic well-differentiated glandular neoplasm with abundant neutrophils within the luminae of the tumoral glands. The tumor failed to express p63 and cytokeratin 5/6, whereas it was intensively positive for CK7 and E-cadherin. CDX2 expression was weak and focal. The immunohistochemical expression of DNA mismatch-repair proteins (MSH2, MSH6, MLH1, and PMS2) was preserved. Despite oncological treatment, the patient developed multiple cutaneous metastases during the ensuing several months, and eventually died 6 years after her initial diagnosis with widespread metastases.
Role of Direct Immunofluorescence in Cutaneous Small-Vessel Vasculitis: Experience From a Tertiary Center
Authors: Lath Khushboo , Chatterjee Debajyoti , Saikia Uma Nahar , Saikia Biman , Minz Ranjana , De Dipankar , Handa Sanjeev , Radotra Bishan
Published: April 2018

Skin is commonly affected by vasculitic process and often subjected to biopsy. Cutaneous vasculitis can be either primary or part of a systemic vasculitic process. This study was conducted to evaluate the diagnostic utility of direct immunofluorescence (DIF) in determination of etiology of cutaneous vasculitis. All histologically proven cases of cutaneous vasculitis over the past two and half years were retrospectively analyzed along with their clinical and DIF findings (IgG, IgA, IgM, and C3). Within this study period, a total of 198 cases of small-vessel vasculitis were diagnosed based on skin biopsy and DIF findings. The mean age of patients was 31.2 years (range 1–84 years) with slight male dominance (M:F ratio 1.06:1). Henoch–Schonlein purpura/IgA vasculitis was the commonest clinical diagnosis (31%), followed by urticarial vasculitis (11%) and others. Idiopathic vasculitis was suspected in 33% cases. Overall, DIF was positive in 60% (119/198) cases, with vascular deposition of IgA being commonest, followed by C3. The clinical diagnosis of Henoch–Schonlein purpura could be confirmed in 61.5% (40/65) cases by DIF, whereas another 20 unsuspected cases were picked up as IgA vasculitis based on DIF findings. DIF findings confirmed lupus vasculitis in 50% cases. Other cases showed variable nonspecific deposition of C3 and IgM in 42% cases. DIF can be highly useful to classify cutaneous vasculitis, with maximum efficacy for diagnosis of IgA vasculitis and lupus vasculitis. It can aid in the accurate diagnosis even when the histological changes are minimal. All cases of suspected cutaneous vasculitis should be subjected to DIF.
Replacement of the 6-Min Walk Test With Glittre ADL Test and Scores From the PFSDQ-M and HAP Questionnaires in the BODE Index
Authors: Moreira Fabiana B. R. , de Fuccio Marcelo B. , Ribeiro-Samora Giane Amorim , Velloso Marcelo
Published: April 2018

Purpose:

Chronic obstructive pulmonary disease reduces functional capacity, which is strongly correlated with the morbidity and mortality of patients. The BODE index considers the multifactorial nature of the disease, including the functional capacity measured by the 6-min walk test (6MWT), and this index predicts the mortality in patients with chronic obstructive pulmonary disease. Our aim was to assess whether association exists between the original BODE index and the modified BODE index by replacing the 6MWT with the scores from the Pulmonary Functional Status and Dyspnea Questionnaire—Modified version (PFSDQ-M), Human Activity Profile (HAP) questionnaire, and the results of the Glittre ADL Test (TGlittre).

Methods:

Twenty-eight subjects diagnosed with chronic obstructive pulmonary disease underwent the 6MWT and TGlittre and responded to the PFSDQ-M and HAP questionnaires. Four BODE index scores were obtained: 1 calculated by using the original method (ie, using the 6MWT) and 3 others calculated by using the results obtained from the TGlittre, PFSDQ-M, and HAP (the modified BODE index scores).

Results:

High levels of association were observed between the original BODE index and the BODE TGlittre (R
2 = 0.824, P ≤ .0001), BODE PFSDQ-M (R
2 = 0.803, P ≤ .0001), and BODE HAP (R
2 = 0.500, P ≤ .0001).

Conclusion:

The BODE TGlittre, and BODE PFSDQ-M may be used as alternatives to the 6MWT when physical space is not available to perform the 6MWT or when the condition of a patient does not allow performance of the 6MWT.
Cortical astrocytes prime the induction of spine plasticity and mirror image pain
Authors: Ishikawa Tatsuya , Eto Kei , Kim Sun Kwang , Wake Hiroaki , Takeda Ikuko , Horiuchi Hiroshi , Moorhouse Andrew J. , Ishibashi Hitoshi , Nabekura Junichi
Published: April 2018

Peripheral nerve injury causes maladaptive plasticity in the central nervous system and induces chronic pain. In addition to the injured limb, abnormal pain sensation can appear in the limb contralateral to the injury, called mirror image pain. Because synaptic remodeling in the primary somatosensory cortex (S1) has critical roles in the induction of chronic pain, cortical reorganization in the S1 ipsilateral to the injured limb may also accompany mirror image pain. To elucidate this, we conducted in vivo 2-photon calcium imaging of neuron and astrocyte activity in the ipsilateral S1 after a peripheral nerve injury. We found that cross-callosal inputs enhanced the activity of both S1 astrocytes and inhibitory neurons, whereas activity of excitatory neurons decreased. When local inhibitory circuits were blocked, astrocyte-dependent spine plasticity and allodynia were revealed. Thus, we propose that cortical astrocytes prime the induction of spine plasticity and mirror image pain after peripheral nerve injury. Moreover, this result suggests that cortical synaptic rewiring could be sufficient to cause allodynia on the uninjured periphery.