bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanisms of Simultaneous Hydraulic-Fracture Propagation From Multiple Perforation Clusters in Horizontal Wells
Authors: Wu Kan , Olson Jon E. 
Published: December 2015

Summary
Simultaneous multiple-fracture treatments in horizontal wellbores are becoming a prevalent approach to economically develop unconventional resources in shale reservoirs. One challenge to efficiently use the technique is the generation of effective hydraulic fractures from all perforation clusters. In this work, we conducted a fundamental study of physical mechanisms controlling simultaneous multiple-fracture propagation and discussed the potential approaches to improve nonuniform development of multiple fractures. This study was investigated by our recently developed 3D fracture-propagation model that captures the coupled elastic deformation of the rock with fluid flow in the horizontal wellbore and within the fractures. The model demonstrated that fracture geometry was controlled by both the stress-shadow effects and dynamic partitioning of flow rate. The analysis results indicated that the nonuniform development of a multiple-fracture array, for example, a three-fracture array in this study, was induced by the uneven partitioning of flow rate into each fracture, which was dependent on the flow resistance from wellbore friction, perforation friction, and fracture propagation. Furthermore, the stress shadowing from the exterior fractures exerted additional stress on the interior fractures and increased the resistance of fracture propagation, resulting in the interior fractures receiving much less fluid. To minimize the negative effects of stress shadowing and favor more-uniform fracture growth, we investigated potential approaches to promote uniform partitioning of flow rate through adjusting the flow resistance between multiple fractures. The results showed that adjusting perforation friction can provide an effective way to modify the partitioning of flow rate and mitigate the negative effects of stress shadowing. The mechanisms investigated in this study are consistent with field observations. Our approach can help field operators to improve the effectiveness of multiple fracturing treatments and maximize the production.
Optic nerve mobilization to enhance the exposure of the pituitary stalk during craniopharyngioma resection: early experience
Authors: Metwali Hussam , Gerganov Venelin , Fahlbusch Rudolf 
Published: December 2015

OBJECT
Preservation of the pituitary stalk and its vasculature is a key step in good postoperative endocrinological outcome in patients with craniopharyngiomas. In this article, the authors describe the surgical technique of medial optic nerve mobilization for better inspection and preservation of the pituitary stalk.

METHODS
This operative technique has been applied in 3 patients. Following tumor exposure via a frontolateral approach, the pituitary stalk could be seen partially hidden under the optic nerve and the optic chiasm. The subchiasmatic and opticocarotid spaces were narrow, and tumor dissection from the pituitary stalk under direct vision was not possible. The optic canal was therefore unroofed, the falciform ligament was incised, and the lateral part of the tuberculum sellae was drilled medial to the optic nerve. The optic nerve could be mobilized medially to widen the opticocarotid triangle, which enhanced visualization of and access to the pituitary stalk.

RESULTS
By using the optic nerve mobilization technique, the tumor could be removed completely, and the pituitary stalk and its vasculature were preserved in all patients. In 2 patients, vision improved after surgery, while in 1 patient it remained normal, as it was before surgery. The hormonal status remained normal after surgery in 2 patients. In the patient with preoperative hormonal deficiencies, improvement occurred early after surgery and hormonal levels were normal after 3 months. No approach-related complications occurred.

CONCLUSIONS
This early experience shows that this technique is safe and could be used as a complementary step during microsurgery of craniopharyngiomas. It allows for tumor dissection from the pituitary stalk under direct vision. The pituitary stalk can thus be preserved without jeopardizing the optic nerve.
Computed tomography parameters for atlantooccipital dislocation in adult patients: the occipital condyle–C1 interval
Authors: Martinez-del-Campo Eduardo , Kalb Samuel , Soriano-Baron Hector , Turner Jay D. , Neal Matthew T. , Uschold Timothy , Theodore Nicholas 
Published: December 2015

OBJECT
Atlantooccipital dislocation (AOD) in adults cannot be diagnosed with adequate specificity and sensitivity using only CT or plain radiography, and the spine literature offers no guidelines. In children, the most sensitive and specific radiographic measurement for the diagnosis of AOD is the CT-based occipital condyle–C1 interval (CCI). The goal of the current study was to identify the normal CCI in healthy adults and compare it with the CCI in adults with AOD to establish a highly sensitive and specific cutoff value for the neuroimaging diagnosis of AOD.

METHODS
A total of 81 patients, 59 without AOD and 22 with AOD, were included in this study. Measurements obtained from thin-slice CT scans of the craniovertebral joint to assess atlantooccipital dislocation included the CCI, condylar sum, the Wholey and Harris intervals, Powers and Sun ratios, Wackenheim line, and Lee X-lines.

RESULTS
The group of patients without AOD included 30 men (50.8%) and 29 women (49.2%) with a mean age of 42.4 ± 16 years (range 19–87 years). The group of patients with AOD included 10 men (45.5%) and 12 women (54.5%) with a mean age of 38.2 ± 9.7 years (range 20–56 years). Interrater reliabilities within a 95% CI were all greater than 0.98 for CCI measurements. A total of 1296 measurements of the CCI were made in 81 patients. The mean CCI for non-AOD patients was 0.89 ± 0.12 mm, the single largest CCI measurement was 1.4 mm, and the largest mean for either right or left CCI was 1.2 mm. The mean condylar sum was 1.8 ± 0.2 mm, and the largest condylar sum value was 2.2 mm. Linear regression with age predicted an increase in CCI of 0.001 mm/year (p < 0.05). The mean CCI in AOD patients was 3.35 ± 0.18 mm (range 1.5 mm–6.4 mm). The shortest single CCI measurements in the AOD patients were 1.1 mm and 1.2 mm. The mean condylar sum for all 22 AOD patients was 6.7 ± 2.7 mm and the shortest condylar sums were 3.0 mm. Cutoff values for AOD were set at 1.5 mm for the CCI and 3.0 mm for the condylar sum, both with a sensitivity of 1 and false-negative rate of 0. Sensitivity for the Powers, Wholey, Harris, Sun, Wackenheim, and Lee criteria were determined to be 0.55, 0.46, 0.27, 0.23, 0.41, and 0.41, respectively.

CONCLUSIONS
The CCI is shorter in adult patients as opposed to the pediatric population. The revised CCI (1.5 mm) and condylar sum (3.0 mm) cutoff values have the highest sensitivity and specificity for the diagnosis of AOD in the adult population.
Simultaneous bilateral stereotactic procedure for deep brain stimulation implants: a significant step for reducing operation time
Authors: Fonoff Erich Talamoni , Azevedo Angelo , Angelos Jairo Silva dos , Martinez Raquel Chacon Ruiz , Navarro Jessie , Reis Paul Rodrigo , Sepulveda Miguel Ernesto San Martin , Cury Rubens Gisbert , Ghilardi Maria Gabriela dos Santos , Teixeira Manoel Jacobsen , Lopez William Omar Contreras 
Published: December 2015

OBJECT
Currently, bilateral procedures involve 2 sequential implants in each of the hemispheres. The present report demonstrates the feasibility of simultaneous bilateral procedures during the implantation of deep brain stimulation (DBS) leads.

METHODS
Fifty-seven patients with movement disorders underwent bilateral DBS implantation in the same study period. The authors compared the time required for the surgical implantation of deep brain electrodes in 2 randomly assigned groups. One group of 28 patients underwent traditional sequential electrode implantation, and the other 29 patients underwent simultaneous bilateral implantation. Clinical outcomes of the patients with Parkinson's disease (PD) who had undergone DBS implantation of the subthalamic nucleus using either of the 2 techniques were compared.

RESULTS
Overall, a reduction of 38.51% in total operating time for the simultaneous bilateral group (136.4 ± 20.93 minutes) as compared with that for the traditional consecutive approach (220.3 ± 27.58 minutes) was observed. Regarding clinical outcomes in the PD patients who underwent subthalamic nucleus DBS implantation, comparing the preoperative off-medication condition with the off-medication/on-stimulation condition 1 year after the surgery in both procedure groups, there was a mean 47.8% ± 9.5% improvement in the Unified Parkinson's Disease Rating Scale Part III (UPDRS-III) score in the simultaneous group, while the sequential group experienced 47.5% ± 15.8% improvement (p = 0.96). Moreover, a marked reduction in the levodopa-equivalent dose from preoperatively to postoperatively was similar in these 2 groups. The simultaneous bilateral procedure presented major advantages over the traditional sequential approach, with a shorter total operating time.

CONCLUSIONS
A simultaneous stereotactic approach significantly reduces the operation time in bilateral DBS procedures, resulting in decreased microrecording time, contributing to the optimization of functional stereotactic procedures.
Mobile spine chordoma: results of 166 patients from the AOSpine Knowledge Forum Tumor database
Authors: Gokaslan Ziya L. , Zadnik Patricia L. , Sciubba Daniel M. , Germscheid Niccole , Goodwin C. Rory , Wolinsky Jean-Paul , Bettegowda Chetan , Groves Mari L. , Luzzati Alessandro , Rhines Laurence D. , Fisher Charles G. , Varga Peter Pal , Dekutoski Mark B. , Clarke Michelle J. , Fehlings Michael G. , Quraishi Nasir A. , Chou Dean , Reynolds Jeremy J. , Williams Richard P. , Kawahara Norio , Boriani Stefano 
Published: December 2015

OBJECT
A chordoma is an indolent primary spinal tumor that has devastating effects on the patient's life. These lesions are chemoresistant, resistant to conventional radiotherapy, and moderately sensitive to proton therapy; however, en bloc resection remains the preferred treatment for optimizing patient outcomes. While multiple small and largely retrospective studies have investigated the outcomes following en bloc resection of chordomas in the sacrum, there have been few large-scale studies on patients with chordomas of the mobile spine. The goal of this study was to review the outcomes of surgically treated patients with mobile spine chordomas at multiple international centers with respect to local recurrence and survival. This multiinstitutional retrospective study collected data between 1988 and 2012 about prognosis-predicting factors, including various clinical characteristics and surgical techniques for mobile spine chordoma. Tumors were classified according to the Enneking principles and analyzed in 2 treatment cohorts: Enneking-appropriate (EA) and Enneking-inappropriate (EI) cohorts. Patients were categorized as EA when the final pathological assessment of the margin matched the Enneking recommendation; otherwise, they were categorized as EI.

METHODS
Descriptive statistics were used to summarize the data (Student t-test, chi-square, and Fisher exact tests). Recurrence and survival data were analyzed using Kaplan-Meier survival curves, log-rank tests, and multivariate Cox proportional hazard modeling.

RESULTS
A total of 166 patients (55 female and 111 male patients) with mobile spine chordoma were included. The median patient follow-up was 2.6 years (range 1 day to 22.5 years). Fifty-eight (41%) patients were EA and 84 (59%) patients were EI. The type of biopsy (p < 0.001), spinal location (p = 0.018), and if the patient received adjuvant therapy (p < 0.001) were significantly different between the 2 cohorts. Overall, 58 (35%) patients developed local recurrence and 57 (34%) patients died. Median survival was 7.0 years postoperative: 8.4 years postoperative for EA patients and 6.4 years postoperative for EI patients (p = 0.023). The multivariate analysis showed that the EI cohort was significantly associated with an increased risk of local recurrence in comparison with the EA cohort (HR 7.02; 95% CI 2.96–16.6; p < 0.001), although no significant difference in survival was observed.

CONCLUSIONS
EA resection plays a major role in decreasing the risk for local recurrence in patients with chordoma of the mobile spine.
Spinal arteriovenous shunts: accuracy of shunt detection, localization, and subtype discrimination using spinal magnetic resonance angiography and manual contrast injection using a syringe
Authors: Unsrisong Kittisak , Taphey Siriporn , Oranratanachai Kanokporn 
Published: December 2015

OBJECT
The object of this study was to evaluate the accuracy of fast 3D contrast-enhanced spinal MR angiography (MRA) using a manual syringe contrast injection technique for detecting and evaluating spinal arteriovenous shunts (AVSs).

METHODS
This was a retrospective study of 15 patients and 20 spinal MRA and catheter angiography studies. The accuracy of using spinal MRA to detect spinal AVS, localize shunts, and discriminate the subtype and dominant arterial feeder of the AVS were studied.

RESULTS
There were 14 pretherapeutic and 6 posttherapeutic follow-up spinal MRA and catheter spinal angiography studies. The spinal AVS was demonstrated in 17 of 20 studies. Spinal MRA demonstrated 100% sensitivity for detecting spinal AVS with no false-negative results. A 97% accuracy rate for AVS subtype discrimination and shunt level localization was achieved using this study's diagnostic criteria. The detection of the dominant arterial feeder was limited to 9 of these 17 cases (53%).

CONCLUSIONS
The fast 3D contrast-enhanced MRA technique performed using manual syringe contrast injection can detect the presence of a spinal AVS, locate the shunt level, and discriminate AVS subtype in most cases, but is limited when detecting small arterial feeders.
Development and initial evaluation of a finite element model of the pediatric craniocervical junction
Authors: Phuntsok Rinchen , Mazur Marcus D. , Ellis Benjamin J. , Ravindra Vijay M. , Brockmeyer Douglas L. 
Published: December 2015

OBJECT
There is a significant deficiency in understanding the biomechanics of the pediatric craniocervical junction (CCJ) (occiput–C2), primarily because of a lack of human pediatric cadaveric tissue and the relatively small number of treated patients. To overcome this deficiency, a finite element model (FEM) of the pediatric CCJ was created using pediatric geometry and parameterized adult material properties. The model was evaluated under the physiological range of motion (ROM) for flexion-extension, axial rotation, and lateral bending and under tensile loading.

METHODS
This research utilizes the FEM method, which is a numerical solution technique for discretizing and analyzing systems. The FEM method has been widely used in the field of biomechanics. A CT scan of a 13-month-old female patient was used to create the 3D geometry and surfaces of the FEM model, and an open-source FEM software suite was used to apply the material properties and boundary and loading conditions and analyze the model. The published adult ligament properties were reduced to 50%, 25%, and 10% of the original stiffness in various iterations of the model, and the resulting ROMs for flexion-extension, axial rotation, and lateral bending were compared. The flexion-extension ROMs and tensile stiffness that were predicted by the model were evaluated using previously published experimental measurements from pediatric cadaveric tissues.

RESULTS
The model predicted a ROM within 1 standard deviation of the published pediatric ROM data for flexion-extension at 10% of adult ligament stiffness. The model's response in terms of axial tension also coincided well with published experimental tension characterization data. The model behaved relatively stiffer in extension than in flexion. The axial rotation and lateral bending results showed symmetric ROM, but there are currently no published pediatric experimental data available for comparison. The model predicts a relatively stiffer ROM in both axial rotation and lateral bending in comparison with flexion-extension. As expected, the flexion-extension, axial rotation, and lateral bending ROMs increased with the decrease in ligament stiffness.

CONCLUSIONS
An FEM of the pediatric CCJ was created that accurately predicts flexion-extension ROM and axial force displacement of occiput–C2 when the ligament material properties are reduced to 10% of the published adult ligament properties. This model gives a reasonable prediction of pediatric cervical spine ligament stiffness, the relationship between flexion-extension ROM, and ligament stiffness at the CCJ. The creation of this model using open-source software means that other researchers will be able to use the model as a starting point for research.
Event-driven RBAC
Authors: Bonatti Piero , Galdi Clemente , Torres Davide 
Published: December 2015

Context-aware access control systems should reactively adapt access control decisions to dynamic environmental conditions. In this paper we present ERBAC – an event-driven extension of the TRBAC model that allows the specification and enforcement of general reactive policies – and its implementation. While almost all the individual features of ERBAC occur separately in some previous model, the detailed design of the policy language, its implementation in XACML, and its testing contribute to the development of expressive, event-driven policy frameworks by demonstrating that this rich model can be satisfactorily implemented, and that its expressivity and performance are compatible with a variety of realistic application scenarios. In particular, a number of examples illustrate ERBAC’s expressive power, and its ability of handling exceptional situations in a flexible way, while keeping policies compact and manageable. The prototype extends XACML’s language and the implementation of the PDP to support the new model. Systematic scalability experiments show that the computational cost of policy rule evaluation in ERBAC is compatible with real-world applications.
La pluviométrie ibérique
Authors: Gaussen Henri 
Published: December 2015

RÉSUMÉ.
Dans l'Ibérie humide il y a des précipitations durant toute l'année, la position géographique, la proximité de la mer et de la montagne s'unissent pour donner des précipitations qui dépassent 3 m sur les hautes chaînes. En Galice et Asturies le minimum est en été, aux Pyrénées orientales en hiver.
l'Ibérie xérothère (à été sec) a un front occidental à maximum hivernal diminuant du N au S.
La partie centrale de la péninsule subit en été l'influence de l'anticyclone des Acores et en hiver celle de l'anticyclone de la Meseta. Il y a ainsi un minimum estival et un minimum hivernal. Pour l'Ebre et l'E, le type IIP provoque le maximum de printemps, au bassin du Tage et au Nord-Meseta ; IVe, Ve et VIe fournissent un maximum d'automne. Les sierras de Gredos et Estrella sont plus pluvieuses à leur versant Sud qu'à leur versant Nord par l'action du cyclone de Gibraltar.
La côte du Levant et les Baléares ont un double minimum. L'estival est déterminé par l'anticyclone des Açores, l'hivernal par les flux d'air froid au front oriental de l'anticyclone centre- ibérique.
Le total annuel est plus grand qu'au centre, en particulier aux montagnes d'Alcoy qui sont fortement maritimes et sur la crête montagneuse de Majorque.
Le front Sud-Est est sec presque toute l'année, n'atteignant pas 300 mm de précipitations. Les quelques pluies éparses tombent surtout en fin d'automne et en hiver et sont causées par le cyclone de Gibraltar. L'influence pluvieuse du cyclone des Baléares ne s'étend pas si loin vers le SW. Le type IV" n'a pas d'action par suite de la protection des chaînes de montagnes contre les influences de l'Ouest.
Enfin l'Andalousie a, comme la Meseta, deux minima de précipitations, mais celui de Janvier est moins marqué que celui de l'été. Ils sont produits par l'anticyclone centre-ibérique. L'hiver vient après l'automne pour les précipitations. Les montagnes méridionales reçoivent beaucoup d'eau (Sa. de Grazalema 2.471 mm) qui vient en partie de l'W sous l'influence du cyclone de Gibraltar.
En somme, l'Ibérie a beaucoup de types de temps et de cycles annuels inconnus en Europe centrale. Elle le doit à sa position géographique et à sa structure orographique qui créent pour elle des conditions très variées.
En conclusion, cette analyse montre la richesse de l'étude de Lautensach ; elle apporte une documentation très précieuse pour la connaissance de la pluviométrie ibérique.
Le blé : géohistoire d’un grain au cœur du pouvoir
Authors: Abis Sébastien 
Published: December 2015

Le blé se situe depuis toujours au cœur de l’Histoire et des jeux de puissance. Enjeu central de l’Antiquité, il s’inscrit dans les stratégies d’approvisionnement, par le commerce mais aussi la guerre, déjà dans une perspective de sécurisation de cette ressource vitale. Dans l’histoire de France, par l’impôt, la « guerre des farines » et les politiques menées, le rôle du blé dans la politique et la sécurité fut majeur. Au XX e siècle, c’est en sa qualité de ressource stratégique dans les équilibres sociopolitiques et géoéconomiques qu’il tient un rôle central puisqu’il devient un vecteur de puissance internationale pour les grands exportateurs. Atout majeur de la puissance française, le blé pourrait bien devenir un élément clé du développement économique et de la politique extérieure de la France.
Beryllium-Induced Hypersensitivity: Genetic Susceptibility and Neoantigen Generation
Authors: Fontenot Andrew P. , Falta Michael T. , Kappler John W. , Dai Shaodong , McKee Amy S. 
Published: December 2015

Abstract
Chronic beryllium (Be) disease is a granulomatous lung disorder that results from Be exposure in a genetically susceptible host. The disease is characterized by the accumulation of Be-responsive CD4+ T cells in the lung, and genetic susceptibility is primarily linked to HLA-DPB1 alleles possessing a glutamic acid at position 69 of the β-chain. Recent structural analysis of a Be-specific TCR interacting with a Be-loaded HLA-DP2–peptide complex revealed that Be is coordinated by amino acid residues derived from the HLA-DP2 β-chain and peptide and showed that the TCR does not directly interact with the Be2+ cation. Rather, the TCR recognizes a modified HLA-DP2–peptide complex with charge and conformational changes. Collectively, these findings provide a structural basis for the development of this occupational lung disease through the ability of Be to induce posttranslational modifications in preexisting HLA-DP2–peptide complexes, resulting in the creation of neoantigens.