bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protección al arranque en seco de sistemas lubricados utilizando recubrimientos autolubricantes depositados por pulverización catódica en combinación con lubricantes comerciales
Authors: González Carmona Juan Manuel , Ortega Portilla Carolina , Amaya Hoyos César Andrés , Hross Ralf , Blandón Francisco , Cabal Larrarte Jorge , Morales Jorge Enrique , Sequeda Federico 
Published: May 2017

El arranque en frío de sistemas lubricados genera un gran desgaste debido a la falla de la película lubricante, lo cual produce contacto entre las superficies y origina partículas abrasivas que hacen del desgaste un proceso acumulativo. Esto causa problemas por paradas inesperadas, cambio en calendarios de mantenimiento y pérdida de tiempo, dinero y energía. Con el fin de proteger las piezas industriales durante el arranque en frío y cuando se presenta una falla de la película lubricante, considerada esta como una transición de lubricación mixta a lubricación por capa límite, se realizó un estudio del comportamiento de los lubricantes sólidos aplicados sobre superficies de acero inoxidable AISI 304, recubiertas con bicapas de bisulfuro de tungsteno/titanio (WS2/Ti) en ambientes sin lubricación y en ambientes lubricados con diversos fluidos utilizados en la industria de reductores, rodamientos y elementos hidráulicos. Utilizando diferentes técnicas de análisis, se determinaron la estructura cristalina, las propiedades superficiales, las mecánicas y las tribológicas en seco y con los lubricantes comerciales SHELL OMALA S4GX-220 y TELLUS S4ME-46, proporcionados por la compañía UMACO & CIA SAS se determinó que las propiedades básicas del recubrimiento influencian su comportamiento tribológico, con una reducción del coeficiente de fricción y el desgaste con respectoa las pruebas en seco y al sustrato utilizado, y que la formación de partículas abrasivas inducen una reducción en la resistencia al rayado en seco y scuffing/ scoring en sistemas lubricados
Corrosión a alta temperatura de las aleaciones 9Cr-1Mo modificado, 2,25Cr-1Mo y 304H preoxidadas, en un electrolito de na2So4, mediante técnicas electroquímicas y gravimétricas
Authors: Peña Ballesteros Darío Yesid , Estupiñán Durán Hugo , Vásquez Quintero Custodio , Cáceres Elsa , Ortíz Andrea 
Published: May 2017

En el presente trabajo se evaluó la corrosión de tres tipos de aceros, preoxidados y sin preoxidar, en presencia de sulfato de sodio reactivo, empleando técnicas electroquímicas, como resistencia a la polarización, pendientes Tafel e impedancia electroquímica, y técnicas gravimétricas, como ganancia de peso a temperaturas de 600 °C y 650 °C. Se determinó que el acero 304H presenta la menor velocidad de corrosión y además es el más resistente en presencia de Na2SO4 sólido en una atmósfera de aire, debido a que la capa de óxido formada inicialmente se mantuvo aun a altas temperaturas. Para el caso de los aceros ferríticos, existió un ligero incremento de la velocidad de corrosión, con una pequeña difusión de azufre y formación de sulfuros en la interfaz aleación/óxido, puesto que se fracturó dada la diferencia de coeficientes de expansión térmica. En general, un depósito de Na2SO4 sólido sobre los aceros utilizados en sistemas que operan a alta temperatura no es un factor de riesgo que influya en la degradación de los materiales.
Optimizing World-wide Utilization of Renewable Energy Sources in the Power Sector
Authors: Tino Aboumahboub  , Peter Tzscheutschler  , Thomas Hamacher  
Published: May 2017

In view of resource scarcity and environmental issues, transition of the current energy system towards a renewable-based supply seems to be a necessity. The interesting questions within this framework are how such a renewable-based energy system should be structured, and how costly it might be. We investigated the optimal structure of a prospective renewable-based power supply system on the world wide scale. This paper describes the applied simulation technique, which integrates an adequately precise geographical coverage with high temporal resolution. This methodology provides the requirements to properly mimic the geographical dependencies of energy supply and demand as well as short term intermittent patterns of renewable sources. A linear optimization algorithm determines the cost optimal configuration of the prescribed energy system.
Bioclimatic parameters in the design of contemporary buildings: the proposal for the new Town Hall of Deryneia, Cyprus
Authors: A. Michael  , C. Hadjichristos  , F. Bougiatioti  , A. Oikonomou  
Published: May 2017

This study presents the process of the design proposal for the new Town-Hall of Deryneia, Cyprus. Deryneia is a “divided” municipality since 1974 and for this reason the proposed building had to satisfy, apart from the afore-mentioned environmental and architectural demands, the need to express symbolically the political situation. The aim of the study is to evaluate the thermal behaviour, of the proposed architectural design both qualitatively and quantitatively with the use of software. More specifically, this evaluation concerns the thermal behaviour of the building shell, the passive heating and cooling strategies that are integrated to the design, as well as the achieved daylighting conditions. Daylighting conditions are analysed with the use of software for both overcast (winter) and clear (summer and intermediate seasons) sky conditions, in order to evaluate the influence of the roof skylights.
Revisiting the rules for freehand ventriculostomy: a virtual reality analysis
Authors: Raabe Clemens , Fichtner Jens , Beck Jürgen , Gralla Jan , Raabe Andreas 
Published: May 2017

OBJECTIVEFrontal ventriculostomy is one of the most frequent and standardized procedures in neurosurgery. However, many first and subsequent punctures miss the target, and suboptimal placement or misplacement of the catheter is common. The authors therefore reexamined the landmarks and rules to determine the entry point and trajectory with the best hit rate (HtR).METHODSThe authors randomly selected CT scans from their institution’s DICOM pool that had been obtained in 50 patients with normal ventricular and skull anatomy and without ventricular puncture. Using a 5 × 5–cm frontal grid with 25 entry points referenced to the bregma, the authors examined trajectories 1) perpendicular to the skull, 2) toward classic facial landmarks in the coronal and sagittal planes, and 3) toward an idealized target in the middle of the ipsilateral anterior horn (ILAH). Three-dimensional virtual reality ventriculostomies were simulated for these entry points; trajectories and the HtRs were recorded, resulting in an investigation of 8000 different virtual procedures.RESULTSThe best HtR for the ILAH was 86% for an ideal trajectory, 84% for a landmark trajectory, and 83% for a 90° trajectory, but only at specific entry points. The highest HtRs were found for entry points 3 or 4 cm lateral to the midline, but only in combination with a trajectory toward the contralateral canthus; and 1 or 2 cm lateral to the midline, but only paired with a trajectory toward the nasion. The same “pairing” exists for entry points and trajectories in the sagittal plane. For perpendicular (90°) trajectories, the best entry points were at 3–5 cm lateral to the midline and 3 cm anterior to the bregma, or 4 cm lateral to the midline and 2 cm anterior to the bregma.CONCLUSIONSOnly a few entry points offer a chance of a greater than 80% rate of hitting the ILAH, and then only in combination with a specific trajectory. This “pairing” between entry point and trajectory was found both for landmark targeting and for perpendicular trajectories, with very limited variability. Surprisingly, the ipsilateral medial canthus, a commonly reported landmark, had low HtRs, and should not be recommended as a trajectory target.
Long-term risk of recurrence and regrowth after gross-total and subtotal resection of sporadic vestibular schwannoma
Authors: Nakatomi Hirofumi , Jacob Jeffrey T. , Carlson Matthew L. , Tanaka Shota , Tanaka Minoru , Saito Nobuhito , Lohse Christine M. , Driscoll Colin L. W. , Link Michael J. 
Published: May 2017

OBJECTIVEThe management of vestibular schwannoma (VS) remains controversial. One commonly cited advantage of microsurgery over other treatment modalities is that tumor removal provides the greatest chance of long-term cure. However, there are very few publications with long-term follow-up to support this assertion. The purpose of the current study is to report the very long-term risk of recurrence among a large historical cohort of patients who underwent microsurgical resection.METHODSThe authors retrospectively reviewed the medical records of patients who had undergone primary microsurgical resection of unilateral VS via a retrosigmoid approach performed by a single neurosurgeon-neurotologist team between January 1980 and December 1999. Complete tumor removal was designated gross-total resection (GTR), and anything less than complete removal was designated subtotal resection (STR). The primary end point was radiological recurrence-free survival. Time-to-event analyses were performed to identify factors associated with recurrence.RESULTSFour hundred fourteen patients met the study inclusion criteria and were analyzed. Overall, 67 patients experienced recurrence at a median of 6.9 years following resection (IQR 3.9–12.1, range 1.2–22.5 years). Estimated recurrence-free survival rates at 5, 10, 15, and 20 years following resection were 93% (95% CI 91–96, 248 patients still at risk), 78% (72–85, 88), 68% (60–77, 47), and 51% (41–64, 22), respectively. The strongest predictor of recurrence was extent of resection, with patients who underwent STR having a nearly 11-fold greater risk of recurrence than the patients treated with GTR (HR 10.55, p < 0.001). Among the 18 patients treated with STR, 15 experienced recurrence at a median of 2.7 years following resection (IQR 1.9–8.9, range 1.2–18.7). Estimated recurrence-free survival rates at 5, 10, 15, and 20 years following GTR were 96% (95% CI 93–98, 241 patients still at risk), 82% (77–89, 86), 73% (65–81, 46), and 56% (45–70, 22), respectively. Estimated recurrence-free survival rates at 5, 10, and 15 years following STR were 47% (95% CI 28–78, 7 patients still at risk), 17% (5–55, 2), and 8% (1–52, 1), respectively.CONCLUSIONSLong-term surveillance is required following microsurgical resection of VS even after GTR. Subtotal resection alone should not be considered a definitive long-term cure. These data emphasize the importance of long-term follow-up when reporting tumor control outcomes for VS.
The relationship of dose to nerve volume in predicting pain recurrence after stereotactic radiosurgery in trigeminal neuralgia
Authors: Wolf Amparo , Tyburczy Amy , Ye Jason Chao , Fatterpekar Girish , Silverman Joshua S. , Kondziolka Douglas 
Published: May 2017

OBJECTIVEApproximately 75%–92% of patients with trigeminal neuralgia (TN) achieve pain relief after Gamma Knife surgery (GKS), although a proportion of these patients will experience recurrence of their pain. To evaluate the reasons for durability or recurrence, this study determined the impact of trigeminal nerve length and volume, the nerve dose-volume relationship, and the presence of neurovascular compression (NVC) on pain outcomes after GKS for TN.METHODSFifty-eight patients with 60 symptomatic nerves underwent GKS for TN between 2013 and 2015, including 15 symptomatic nerves secondary to multiple sclerosis (MS). High-resolution MRI was acquired the day of GKS. The median maximum dose was 80 Gy for initial GKS and 65 Gy for repeat GKS. NVC, length and volume of the trigeminal nerve within the subarachnoid space of the posterior fossa, and the ratio of dose to nerve volume were assessed as predictors of recurrence.RESULTSFollow-up was available on 55 patients. Forty-nine patients (89.1%) reported pain relief (Barrow Neurological Institute [BNI] Grades I–IIIb) after GKS at a median duration of 1.9 months. The probability of maintaining pain relief (BNI Grades I–IIIb) without requiring resumption or an increase in medication was 93% at 1 year and 84% at 2 years for patients without MS, and 68% at 1 year and 51% at 2 years for all patients. The nerve length, nerve volume, target distance from the brainstem, and presence of NVC were not predictive of pain recurrence. Patients with a smaller volume of nerve (< 35% of the total nerve volume) that received a high dose (≥ 80% isodose) were less likely to experience recurrence of their TN pain after 1 year (mean time to recurrence: < 35%, 32.2 ± 4.0 months; > 35%, 17.9 ± 2.8 months, log-rank test, χ2 = 4.3, p = 0.039).CONCLUSIONSThe ratio of dose to nerve volume may predict recurrence of TN pain after GKS. Prospective studies are needed to determine the optimal dose to nerve volume ratio and whether this will result in longer pain-free outcomes.
Continuous mapping of the corticospinal tracts in intramedullary spinal cord tumor surgery using an electrified ultrasonic aspirator
Authors: Barzilai Ori , Lidar Zvi , Constantini Shlomi , Salame Khalil , Bitan-Talmor Yifat , Korn Akiva 
Published: May 2017

Intramedullary spinal cord tumors (IMSCTs) represent a rare entity, accounting for 4%–10% of all central nervous system tumors. Microsurgical resection of IMSCTs is currently considered the primary treatment modality. Intraoperative neurophysiological monitoring (IONM) has been shown to aid in maximizing tumor resection and minimizing neurological morbidity, consequently improving patient outcome. The gold standard for IONM to date is multimodality monitoring, consisting of both somatosensory evoked potentials, as well as muscle-based transcranial electric motor evoked potentials (tcMEPs). Monitoring of tcMEPs is optimal when combining transcranial electrically stimulated muscle tcMEPs with D-wave monitoring. Despite continuous monitoring of these modalities, when classic monitoring techniques are used, there can be an inherent delay in time between actual structural or vascular-based injury to the corticospinal tracts (CSTs) and its revelation. Often, tcMEP stimulation is precluded by the surgeon’s preference that the patient not twitch, especially at the most crucial times during resection. In addition, D-wave monitoring may require a few seconds of averaging until updating, and can be somewhat indiscriminate to laterality. Therefore, a method that will provide immediate information regarding the vulnerability of the CSTs is still needed.The authors performed a retrospective series review of resection of IMSCTs using the tip of an ultrasonic aspirator for continuous proximity mapping of the motor fibers within the spinal cord, along with classic muscle-based tcMEP and D-wave monitoring.The authors present their preliminary experience with 6 patients who underwent resection of an IMSCT using the tip of an ultrasonic aspirator for continuous proximity mapping of the motor fibers within the spinal cord, together with classic muscle-based tcMEP and D-wave monitoring. This fusion of technologies can potentially assist in optimizing resection while preserving neurological function in these challenging surgeries.
State of global pediatric neurosurgery outreach: survey by the International Education Subcommittee
Authors: Davis Matthew C. , Rocque Brandon G. , Singhal Ash , Ridder Thomas , Pattisapu Jogi V. , Johnston James M. 
Published: May 2017

OBJECTIVENeurosurgical services are increasingly recognized as essential components of surgical care worldwide. The degree of interest among neurosurgeons regarding international work, and the barriers to involvement in global neurosurgical outreach, are largely unexplored. The authors distributed a survey to members of the American Association of Neurological Surgeons/Congress of Neurological Surgeons (AANS/CNS) Joint Section on Pediatric Neurosurgery to assess the state of global outreach among its members and to identify barriers to involvement.METHODSAn internet-based questionnaire was developed by the International Education Subcommittee of the AANS/CNS Joint Section on Pediatric Neurosurgery and distributed to pediatric neurosurgeons via the AANS/CNS Joint Section email contact list. Participants were surveyed on their involvement in global neurosurgical outreach, geographic location, nature of the participation, and barriers to further involvement.RESULTSA 35.3% response rate was obtained, with 116 respondents completing the survey. Sixty-one percent have performed or taught neurosurgery in a developing country, and 49% travel at least annually. Africa was the most common region (54%), followed by South America (30%), through 29 separate organizing entities. Hydrocephalus was the most commonly treated condition (88%), followed by spinal dysraphism (74%), and tumor (68%). Most respondents obtained follow-up through communications from local surgeons (77%). Seventy-one percent believed the international experience improved their practice, and 74% were very or extremely interested in working elsewhere. Interference with current practice (61%), cost (44%), and difficulty identifying international partners (43%) were the most commonly cited barriers to participation.CONCLUSIONSAny coordinated effort to expand global neurosurgical capacity begins with appreciation for the current state of outreach efforts. Increasing participation in global outreach will require addressing both real and perceived barriers to involvement. Creation and curation of a centralized online database of ongoing projects to facilitate coordination and involvement may be beneficial.
OSSOS. V. Diffusion in the Orbit of a High-perihelion Distant Solar System Object
Authors: Bannister Michele T. , Shankman Cory , Volk Kathryn , Chen 陳 Ying-Tung 英同 , Kaib Nathan , Gladman Brett J. , Jakubik Marian , Kavelaars J. J. , Fraser Wesley C. , Schwamb Megan E. , Petit Jean-Marc , Wang Shiang-Yu , Gwyn Stephen D. J. , Alexandersen Mike , Pike Rosemary E. 
Published: May 2017

Abstract
We report the discovery of the minor planet 2013 SY99 on an exceptionally distant, highly eccentric orbit. With a perihelion of 50.0 au, 2013 SY99’s orbit has a semimajor axis of 730 ± 40 au, the largest known for a high-perihelion trans-Neptunian object (TNO), and well beyond those of (90377) Sedna and 2012 VP113. Yet, with an aphelion of 1420 ± 90 au, 2013 SY99’s orbit is interior to the region influenced by Galactic tides. Such TNOs are not thought to be produced in the current known planetary architecture of the solar system, and they have informed the recent debate on the existence of a distant giant planet. Photometry from the Canada–France–Hawaii Telescope, Gemini North, and Subaru indicate 2013 SY99 is ∼250 km in diameter and moderately red in color, similar to other dynamically excited TNOs. Our dynamical simulations show that Neptune’s weak influence during 2013 SY99’s perihelia encounters drives diffusion in its semimajor axis of hundreds of astronomical units over 4 Gyr. The overall symmetry of random walks in the semimajor axis allows diffusion to populate 2013 SY99’s orbital parameter space from the 1000 to 2000 au inner fringe of the Oort cloud. Diffusion affects other known TNOs on orbits with perihelia of 45 to 49 au and semimajor axes beyond 250 au. This provides a formation mechanism that implies an extended population, gently cycling into and returning from the inner fringe of the Oort cloud.
Comment les médecins choisissent-ils leur lieu d’exercice ?
Authors: Dumontet Magali , Samson Anne-Laure , Franc Carine 
Published: May 2017

À partir d’une base de données exhaustive, restreinte aux médecins généralistes installés en libéral entre 2005 et 2011, cet article étudie les déterminants du choix de leur lieu d’installation au sein d’une région, en distinguant quatre zones : banlieue, ville centre, ville isolée, rurale. Si les variables individuelles influencent relativement peu le choix d’une zone, les caractéristiques de l’offre et de la demande locale de soins, les dispositifs d’exonérations fiscales éventuellement offerts et les équipements disponibles dans chaque zone, expliquent significativement leur choix. Ces résultats sont mobilisés pour simuler l’impact de trois mesures visant à augmenter le nombre de généralistes s’installant en zone rurale.
In Love and Struggle
Authors: Ward Stephen M. 
Published: May 2017

James Boggs (1919-1993) and Grace Lee Boggs (1915-2015) were two largely unsung but critically important figures in the black freedom struggle. Born and raised in Alabama, James Boggs came to Detroit during the Great Migration, becoming an automobile worker and a union activist. Grace Lee was a Chinese American scholar who studied Hegel, worked with Caribbean political theorist C. L. R. James, and moved to Detroit to work toward a new American revolution. As husband and wife, the couple was influential in the early stages of what would become the Black Power movement, laying the intellectual foundation for racial and urban struggles during one of the most active social movement periods in recent U.S. history. Stephen Ward details both the personal and the political dimensions of the Boggses' lives, highlighting the vital contributions these two figures made to black activist thinking. At once a dual biography of two crucial figures and a vivid portrait of Detroit as a center of activism, Ward's book restores the Boggses, and the intellectual strain of black radicalism they shaped, to their rightful place in postwar American history.’
Risk factors and perceived restoration in a town destroyed by the 2010 Chile tsunami
Authors: Martínez Carolina , Rojas Octavio , Villagra Paula , Aránguiz Rafael , Sáez-Carrillo Katia 
Published: May 2017

Abstract. A large earthquake and tsunami took place in February 2010, affecting a significant part of the Chilean coast (Maule earthquake, Mw of 8.8). Dichato (37° S), a small town located on Coliumo Bay, was one of the most devastated coastal areas and is currently under reconstruction. Therefore, the objective of this research is to analyze the risk factors that explain the disaster in 2010, as well as perceived restoration 6 years after the event. Numerical modeling of the 2010 Chile tsunami with four nested grids was applied to estimate the hazard. Physical, socioeconomic and educational dimensions of vulnerability were analyzed for pre- and post-disaster conditions. A perceived restoration study was performed to assess the effects of reconstruction on the community. It was focused on exploring the capacity of newly reconstructed neighborhoods to provide restorative experiences in case of disaster. The study was undertaken using the perceived restorativeness scale. The vulnerability variables that best explained the extent of the disaster were housing conditions, low household incomes and limited knowledge about tsunami events, which conditioned inadequate reactions to the emergency. These variables still constitute the same risks as a result of the reconstruction process, establishing that the occurrence of a similar event would result in a similar degree of devastation. For post-earthquake conditions, it was determined that all neighborhoods have the potential to be restorative environments soon after a tsunami. However, some neighborhoods are still located in areas devastated by the 2010 tsunami and again present high vulnerability to future tsunamis.