bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Nitriding-Quenching and Carburizing-Quenching on Wear Properties of Industrial Pure Iron
Authors: Aramaki M. , Kozin M. , Yoshida K. , Furukimi O. 
Published: June 2018

Abstract
The wear properties of industrial pure iron treated by nitriding-quenching and carburizing-quenching were investigated. Both the nitrogen martensite and carbon martensite produced by each treatment exhibited the same high degree of wear resistance. The results of sliding tests showed that the nano-indentation hardness near the surfaces of both samples had increased. The surface hardening of the nitrogen martensite was more noticeable than that of the carbon martensite. EBSD analysis revealed that plastic strain had been induced on a relatively large scale (around 20 μm) after sliding in the case of the nitrogen martensite. It was found that the high wear resistance of the nitrogen martensite led to strain hardening through the effect of the load applied in the sliding test.
Bleeding risk of cerebral cavernous malformations in patients on β-blocker medication: a cohort study
Authors: Goldberg Johannes , Jaeggi Christian , Schoeni Daniel , Mordasini Pasquale , Raabe Andreas , Bervini David 
Published: June 2018

OBJECTIVECerebral cavernous malformations (CCMs) are frequently diagnosed vascular malformations of the brain. Although most CCMs are asymptomatic, some can be responsible for intracerebral hemorrhage or seizures. In selected cases, microsurgical resection is the preferred treatment option. Treatment with the unselective β-blocker propranolol has been presumed to stabilize and eventually lead to CCM size regression in a limited number of published case series; however, the underlying mechanism and evidence for this effect remain unclear. The aim of this study was to investigate the risk for CCM-related hemorrhage in patients on long-term β-blocker medication.METHODSA single-center database containing data on patients harboring CCMs was retrospectively interrogated for a time period of 35 years. The database included information about hemorrhage and antihypertensive medication. Descriptive and survival analyses were performed, focusing on the risk of hemorrhage at presentation and during follow-up (first or subsequent hemorrhage) in patients on long-term β-blocker medication versus those who were not. Follow-up was censored at the first occurrence of new hemorrhage, surgery, or the last clinical review. For purposes of this analysis, the β-blocker group was divided into the following main subgroups: any β-blocker, β1-selective β-blocker, and any unselective β-blocker.RESULTSOf 542 CCMs among 408 patients, 81 (14.9%) were under treatment with any β-blocker; 65 (12%) received β1-selective β-blocker, and 16 (3%) received any unselective β-blocker. One hundred thirty-six (25.1%) CCMs presented with hemorrhage at diagnosis. None of the β-blocker groups was associated with a lower risk of hemorrhage at the time of diagnosis in a univariate descriptive analysis (any β-blocker: p = 0.64, β1-selective: p = 0.93, any unselective β-blocker: p = 0.25). Four hundred ninety-six CCMs were followed up after diagnosis and included in the survival analysis, for a total of 1800 lesion-years. Follow-up hemorrhage occurred in 36 (7.3%) CCMs. Neither univariate descriptive nor univariate Cox proportional-hazards regression analysis showed a decreased risk for follow-up hemorrhage under treatment with β-blocker medication (any β-blocker: p = 0.70, HR 1.19, 95% CI 0.49–2.90; β1-selective: p = 0.78, HR 1.15, 95% CI 0.44–3.00; any unselective β-blocker: p = 0.76, HR 1.37, 95% CI 0.19–10.08). Multivariate Cox proportional-hazards regression analysis including brainstem location, hemorrhage at diagnosis, age, and any β-blocker treatment showed no reduced risk for follow-up hemorrhage under any β-blocker treatment (p = 0.53, HR 1.36, 95% CI 0.52–3.56).CONCLUSIONSIn this retrospective cohort study, β-blocker medication does not seem to be associated with a decreased risk of CCM-related hemorrhage at presentation or during follow-up.
Isolated subdural hematomas in mild traumatic brain injury. Part 1: the association between radiographic characteristics and neurosurgical intervention
Authors: Orlando Alessandro , Levy A. Stewart , Rubin Benjamin A. , Tanner Allen , Carrick Matthew M. , Lieser Mark , Hamilton David , Mains Charles W. , Bar-Or David 
Published: June 2018

OBJECTIVEIsolated subdural hematomas (iSDHs) are one of the most common intracranial hemorrhage (ICH) types in the population with mild traumatic brain injury (mTBI; Glasgow Coma Scale score 13–15), account for 66%–75% of all neurosurgical procedures, and have one of the highest neurosurgical intervention rates. The objective of this study was to examine how quantitative hemorrhage characteristics of iSDHs in patients with mTBI at admission are associated with subsequent neurosurgical intervention.METHODSThis was a 3.5-year, retrospective observational cohort study at a Level I trauma center. All adult trauma patients with mTBI and iSDHs were included in the study. Maximum length and thickness (in mm) of acute SDHs, the presence of acute-on-chronic SDH, mass effect, and other hemorrhage-related variables were double–data entered; discrepant results were adjudicated after a maximum of 4 reviews. Patients with coagulopathy, skull fractures, no acute hemorrhage, a non-SDH ICH, or who did not undergo imaging on admission were excluded. The primary outcome was neurosurgical intervention (craniotomy, burr hole, catheter drainage of SDH, placement of intracranial pressure monitor, shunt, or ventriculostomy). Multivariate stepwise logistic regression was used to identify significant covariates and to assess interactions.RESULTSA total of 176 patients were included in our study: 28 patients did and 148 patients did not receive a neurosurgical intervention. Increasing head Abbreviated Injury Scale score was significantly associated with neurosurgical interventions. There was a strong correlation between the first 3 reviews on maximum hemorrhage length (R2 = 0.82) and maximum hemorrhage thickness (R2 = 0.80). The neurosurgical intervention group had a mean maximum SDH length and thickness that were 61 mm longer and 13 mm thicker than those of the nonneurosurgical intervention group (p < 0.001 for both). After adjusting for the presence of an acute-on-chronic hemorrhage, for every 1-mm increase in the thickness of an iSDH, the odds of a neurosurgical intervention increase by 32% (95% CI 1.16–1.50). There were no interventions for any SDH with a maximum thickness ≤ 5 mm on initial presenting scan.CONCLUSIONSThis is the first study to quantify the odds of a neurosurgical intervention based on hemorrhage characteristics in patients with an iSDH and mTBI. Once validated in a second population, these data can be used to better inform patients and families of the risk of future neurosurgical intervention, and to evaluate the necessity of interhospital transfers.
Contrast-enhanced ultrasound to visualize hemodynamic changes after rodent spinal cord injury
Authors: Khaing Zin Z. , Cates Lindsay N. , DeWees Dane M. , Hannah Alexander , Mourad Pierre , Bruce Matthew , Hofstetter Christoph P. 
Published: June 2018

OBJECTIVETraumatic spinal cord injury (tSCI) causes an almost complete loss of blood flow at the site of injury (primary injury) as well as significant hypoperfusion in the penumbra of the injury. Hypoperfusion in the penumbra progresses after injury to the spinal cord and is likely to be a major contributor to progressive cell death of spinal cord tissue that was initially viable (secondary injury). Neuroprotective treatment strategies seek to limit secondary injury. Clinical monitoring of the temporal and spatial patterns of blood flow within the contused spinal cord is currently not feasible. The purpose of the current study was to determine whether ultrafast contrast-enhanced ultrasound (CEUS) Doppler allows for detection of local hemodynamic changes within an injured rodent spinal cord in real time.METHODSA novel ultrafast CEUS Doppler technique was developed utilizing a research ultrasound platform combined with a 15-MHz linear array transducer. Ultrafast plane-wave acquisitions enabled the separation of higher-velocity blood flow in macrocirculation from low-velocity flow within the microcirculation (tissue perfusion). An FDA-approved contrast agent (microbubbles) was used for visualization of local blood flow in real time. CEUS Doppler acquisition protocols were developed to characterize tissue perfusion both during contrast inflow and during the steady-state plateau. A compression injury of the thoracic spinal cord of adult rats was induced using iris forceps.RESULTSHigh-frequency ultrasound enabled visualization of spinal cord vessels such as anterior spinal arteries as well as central arteries (mean diameter [± SEM] 145.8 ± 10.0 µm; 76.2 ± 4.5 µm, respectively). In the intact spinal cord, ultrafast CEUS Doppler confirmed higher perfusion of the gray matter compared to white matter. Immediately after compression injury of the thoracic rodent spinal cord, spinal cord vessels were disrupted in an area of 1.93 ± 1.14 mm2. Ultrafast CEUS Doppler revealed a topographical map of local tissue hypoperfusion with remarkable spatial resolution. Critical loss of perfusion, defined as less than 40% perfusion compared to the surrounding spared tissue, was seen within an area of 2.21 ± 0.6 mm2.CONCLUSIONSIn our current report, we introduce ultrafast CEUS Doppler for monitoring of spinal vascular structure and function in real time. Development and clinical implementation of this type of imaging could have a significant impact on the care of patients with tSCI.
Intraoperative angiography via the popliteal artery: a useful technique for patients in the prone position
Authors: Villelli Nicolas W. , Lewis David M. , Leipzig Thomas J. , DeNardo Andrew J. , Payner Troy D. , Kulwin Charles G. 
Published: June 2018

OBJECTIVEIntraoperative angiography can be a valuable tool in the surgical management of vascular disorders in the CNS. This is typically accomplished via femoral artery puncture; however, this can be technically difficult in patients in the prone position. The authors describe the feasibility of intraoperative angiography via the popliteal artery in the prone patient.METHODSThree patients underwent intraoperative spinal angiography in the prone position via vascular access through the popliteal artery. Standard angiography techniques were used, along with ultrasound and a micropuncture needle for initial vascular access. Two patients underwent intraoperative angiography to confirm the obliteration of dural arteriovenous fistulas. The third patient required unexpected intraoperative angiography when a tumor was concerning for a vascular malformation in the cervical spine.RESULTSAll 3 patients tolerated the procedure without complication. The popliteal artery was easily accessed without any adaptation to typical patient positioning for these prone-position cases. This proved particularly beneficial when angiography was not part of the preoperative plan.CONCLUSIONSIntraoperative angiography via the popliteal artery is feasible and well tolerated. It presents significant benefit when obtaining imaging studies in patients in a prone position, with the added benefit of easy access, familiar anatomy, and low concern for catheter thrombosis or kinking.
Development and validation of a predictive model for 90-day readmission following elective spine surgery
Authors: Parker Scott L. , Sivaganesan Ahilan , Chotai Silky , McGirt Matthew J. , Asher Anthony L. , Devin Clinton J. 
Published: June 2018

OBJECTIVEHospital readmissions lead to a significant increase in the total cost of care in patients undergoing elective spine surgery. Understanding factors associated with an increased risk of postoperative readmission could facilitate a reduction in such occurrences. The aims of this study were to develop and validate a predictive model for 90-day hospital readmission following elective spine surgery.METHODSAll patients undergoing elective spine surgery for degenerative disease were enrolled in a prospective longitudinal registry. All 90-day readmissions were prospectively recorded. For predictive modeling, all covariates were selected by choosing those variables that were significantly associated with readmission and by incorporating other relevant variables based on clinical intuition and the Akaike information criterion. Eighty percent of the sample was randomly selected for model development and 20% for model validation. Multiple logistic regression analysis was performed with Bayesian model averaging (BMA) to model the odds of 90-day readmission. Goodness of fit was assessed via the C-statistic, that is, the area under the receiver operating characteristic curve (AUC), using the training data set. Discrimination (predictive performance) was assessed using the C-statistic, as applied to the 20% validation data set.RESULTSA total of 2803 consecutive patients were enrolled in the registry, and their data were analyzed for this study. Of this cohort, 227 (8.1%) patients were readmitted to the hospital (for any cause) within 90 days postoperatively. Variables significantly associated with an increased risk of readmission were as follows (OR [95% CI]): lumbar surgery 1.8 [1.1–2.8], government-issued insurance 2.0 [1.4–3.0], hypertension 2.1 [1.4–3.3], prior myocardial infarction 2.2 [1.2–3.8], diabetes 2.5 [1.7–3.7], and coagulation disorder 3.1 [1.6–5.8]. These variables, in addition to others determined a priori to be clinically relevant, comprised 32 inputs in the predictive model constructed using BMA. The AUC value for the training data set was 0.77 for model development and 0.76 for model validation.CONCLUSIONSIdentification of high-risk patients is feasible with the novel predictive model presented herein. Appropriate allocation of resources to reduce the postoperative incidence of readmission may reduce the readmission rate and the associated health care costs.
Characterization of massive magnetic parts with a dedicated device
Authors: Borsenberger Marc , Benabou Abdelkader , Baudouin Cyrille , Bigot Régis , Faverolle Pierre , Mipo Jean-Claude 
Published: June 2018

Magnetic parts are usually composed of a stack of electrical steel laminations to reduce the eddy current losses. However, for cost reasons or for specific applications the magnetic core can be made from massive steel and thus manufactured with adapted processes such as forging. Such process may lead to inhomogeneous and degraded magnetic properties. Therefore, this study proposes a specific device for characterizing magnetic properties of samples which are to be representative of a massive part. The measure is based on the Faraday’s equation to determine the magnetic flux density and the Hall effect to estimate the magnetic field inside the sample. Practically this is realized with classical components such as Hall probes, a secondary winding and an electromagnet device. However their combination is unique to perform magnetic characterization on massive samples, which are less affected by the sampling technique and may have anisotropic properties. The device is dimensioned thanks to FE-Simulation and validated according repeatability, sensitivity and trueness analysis. Eventually the characterization is performed on samples with different material parameters showing the effect of the grain size on the specific losses. The expected effect of the grain flow on magnetic properties is however not proven yet.
Light Curves of Hydrogen-poor Superluminous Supernovae from the Palomar Transient Factory
Authors: De Cia Annalisa , Gal-Yam A. , Rubin A. , Leloudas G. , Vreeswijk P. , Perley D. A. , Quimby R. , Yan Lin , Sullivan M. , Flörs A. , Sollerman J. , Bersier D. , Cenko S. B. , Gal-Yam M. , Maguire K. , Ofek E. O. , Prentice S. , Schulze S. , Spyromilio J. , Valenti S. , Arcavi I. , Corsi A. , Howell D. A. , Mazzali P. , Kasliwal M. M. , Taddia F. , Yaron O. 
Published: June 2018

Abstract
We investigate the light-curve properties of a sample of 26 spectroscopically confirmed hydrogen-poor superluminous supernovae (SLSNe-I) in the Palomar Transient Factory survey. These events are brighter than SNe Ib/c and SNe Ic-BL, on average, by about 4 and 2 mag, respectively. The peak absolute magnitudes of SLSNe-I in rest-frame g band span −22 ≲ M

g
≲ −20 mag, and these peaks are not powered by radioactive 56Ni, unless strong asymmetries are at play. The rise timescales are longer for SLSNe than for normal SNe Ib/c, by roughly 10 days, for events with similar decay times. Thus, SLSNe-I can be considered as a separate population based on photometric properties. After peak, SLSNe-I decay with a wide range of slopes, with no obvious gap between rapidly declining and slowly declining events. The latter events show more irregularities (bumps) in the light curves at all times. At late times, the SLSN-I light curves slow down and cluster around the 56Co radioactive decay rate. Powering the late-time light curves with radioactive decay would require between 1 and 10 M
⊙ of Ni masses. Alternatively, a simple magnetar model can reasonably fit the majority of SLSNe-I light curves, with four exceptions, and can mimic the radioactive decay of 56Co, up to ∼400 days from explosion. The resulting spin values do not correlate with the host-galaxy metallicities. Finally, the analysis of our sample cannot strengthen the case for using SLSNe-I for cosmology.
On the Use of the Main-sequence Knee (Saddle) to Measure Globular Cluster Ages
Authors: Saracino S. , Dalessandro E. , Ferraro F. R. , Lanzoni B. , Origlia L. , Salaris M. , Pietrinferni A. , Geisler D. , Kalirai J. S. , Correnti M. , Cohen R. E. , Mauro F. , Villanova S. , Bidin C. Moni 
Published: June 2018

Abstract
In this paper, we review the operational definition of the so-called main-sequence knee (MS-knee), a feature in the color-magnitude diagram (CMD) occurring at the low-mass end of the MS. The magnitude of this feature is predicted to be independent of age at fixed chemical composition. For this reason, its difference in magnitude with respect to the MS turn-off (MS-TO) point has been suggested as a possible diagnostic to estimate absolute globular cluster (GC) ages. We first demonstrate that the operational definition of the MS-knee currently adopted in the literature refers to the inflection point of the MS (which we here more appropriately named MS-saddle), a feature that is well distinct from the knee and which cannot be used as its proxy. The MS-knee is only visible in near-infrared CMDs, while the MS-saddle can be also detected in optical–NIR CMDs. By using different sets of isochrones, we then demonstrate that the absolute magnitude of the MS-knee varies by a few tenths of a dex from one model to another, thus showing that at the moment stellar models may not capture the full systematic error in the method. We also demonstrate that while the absolute magnitude of the MS-saddle is almost coincident in different models, it has a systematic dependence on the adopted color combinations which is not predicted by stellar models. Hence, it cannot be used as a reliable reference for absolute age determination. Moreover, when statistical and systematic uncertainties are properly taken into account, the difference in magnitude between the MS-TO and the MS-saddle does not provide absolute ages with better accuracy than other methods like the MS-fitting.
SN 2017ein and the Possible First Identification of a Type Ic Supernova Progenitor
Authors: Van Dyk Schuyler D. , Zheng WeiKang , Brink Thomas G. , Filippenko Alexei V. , Milisavljevic Dan , Andrews Jennifer E. , Smith Nathan , Cignoni Michele , Fox Ori D. , Kelly Patrick L. , Adamo Angela , Yunus Sameen , Zhang Keto , Kumar Sahana 
Published: June 2018

Abstract
We have identified a progenitor candidate in archival Hubble Space Telescope (HST) images for the Type Ic supernova (SN Ic) SN 2017ein in NGC 3938, pinpointing the candidate’s location via HST Target of Opportunity imaging of the SN itself. This would be the first identification of a stellar-like object as a progenitor candidate for any SN Ic to date. We also present observations of SN 2017ein during the first ∼49 days since explosion. We find that SN 2017ein most resembles the well-studied SN Ic SN 2007gr. We infer that SN 2017ein experienced a total visual extinction of A

V
≈ 1.0–1.9 mag, predominantly because of dust within the host galaxy. Although the distance is not well known, if this object is the progenitor, it was likely of high initial mass, ∼47–48 M
⊙ if a single star, or ∼60–80 M
⊙ if in a binary system. However, we also find that the progenitor candidate could be a very blue and young compact cluster, further implying a very massive (>65 M
⊙) progenitor. Furthermore, the actual progenitor might not be associated with the candidate at all and could be far less massive. From the immediate stellar environment, we find possible evidence for three different populations; if the SN progenitor was a member of the youngest population, this would be consistent with an initial mass of ∼57 M
⊙. After it has faded, the SN should be reobserved at high spatial resolution and sensitivity, to determine whether the candidate is indeed the progenitor.
Feasibility of Measurement and Adherence to System Performance Measures for Rheumatoid Arthritis in 5 Models of Care
Authors: Barber Claire E.H. , Thorne J. Carter , Ahluwalia Vandana , Burt Jennifer , Lacaille Diane , Marshall Deborah A. , Hazlewood Glen S. , Mosher Dianne , Denning Lisa , Szamko Ildiko , Chin Ricky , Hamilton Sean , Benseler Susanne , Twilt Marinka , Shiff Natalie J. , Bykerk Vivian , Homik Joanne , Barnabe Cheryl 
Published: June 2018

Objective.To test the feasibility of reporting on 4 national performance measures for patients with rheumatoid arthritis (RA) in 5 different models of care.Methods.The following performance measures were evaluated in 5 models of care: waiting time (WT) to rheumatologist consultation, percentage of patients seen in yearly followup (FU), percentage taking disease-modifying antirheumatic drugs (DMARD), and time to starting DMARD. All models aimed to improve early access and care for patients with RA.Results.A number of feasibility issues were encountered in performance measure evaluation because of differences in site data collection and/or the duration of the model of care. For example, while 4/5 programs maintained clinical or research databases, chart reviews were still required to report on WT. Median WT for care in 2015 varied by site between 21 and 75 days. Yearly FU rates could only be calculated in 2 sites (combined owing to small numbers) and varied between 83% and 100%. Percentage of patients taking a DMARD and time to DMARD could be calculated in 3 models, and rates of DMARD use were between 90% and 100%, with median time to DMARD of 0 days in each.Conclusion.Our review has shown that even in models of care designed to improve access to care and early treatment, data to document improvements are often lacking. Where data were available for measuring, deficits in WT performance were noted for some centers. Our results highlight a need to improve reporting processes to drive quality improvement.