bluuebunny/crossref_metadata_2025_split huggingface dataset:
The stellar distribution function and local vertical potential from Gaia DR2
Authors: Li Haochuan , Widrow Lawrence M 
Published: February 2021

ABSTRACT
We develop a novel method to simultaneously determine the vertical potential, force, and stellar z−vz phase space distribution function (DF) in our local patch of the Galaxy. We assume that the Solar Neighbourhood can be treated as a one-dimensional (1D) system in dynamical equilibrium and directly fit the number density in the z−vz plane to what we call the rational linear distribution function (RLDF) model. This model can be regarded as a continuous sum of isothermal DFs though it has only one more parameter than the isothermal model. We apply our method to a sample of giant stars from Gaia Data Release 2 and show that the RLDF provides an excellent fit to the data. The well-known phase space spiral emerges in the residual map of the z−vz plane. We use the best-fitting potential to plot the residuals in terms of the frequency and angle of vertical oscillations and show that the spiral maps into a straight line. From its slope, we estimate that the phase spirals were generated by a perturbation ∼540 Myr years ago. We also determine the differential surface density as a function of vertical velocity dispersion, a.k.a. the vertical temperature distribution. The result is qualitatively similar to what was previously found for SDSS/SEGUE G dwarfs. Finally, we address parameter degeneracies and the validity of the 1D approximation. Particularly, the mid-plane density derived from a cold sub-sample, where the 1D approximation is more secure, is closer to literature values than that derived from the sample as a whole.
Non-equilibrium ionization and radiative transport in an evolving supernova remnant
Authors: Sarkar Kartick C , Gnat Orly , Sternberg Amiel 
Published: February 2021

ABSTRACT
We present numerical simulations of the evolution of a supernova (SN) remnant expanding into a uniform background medium with density $n_\mathrm{ H} = 1.0\, \mbox{ cm}^{-3}$ and temperature of 104 K. We include a dynamically evolving non-equilibrium ionization (NEI) network (consisting of all the ions of H, He, C, N, O, Ne, Mg, Si, S, Fe), frequency dependent radiation transfer (RT), thermal conduction, and a simple dust evolution model, all intra-coupled to each other and to the hydrodynamics. We assume spherical symmetry. Photoionization, radiation losses, photo-heating, charge-exchange heating/cooling, and radiation pressure are calculated on the fly depending on the local radiation field and ion fractions. We find that the dynamics and energetics (but not the emission spectra) of the SN remnants can be well modelled by collisional equilibrium cooling curves even in the absence of non-equilibrium cooling and radiative transport. We find that the effect of precursor ionizing radiation at different stages of SN remnant are dominated by rapid cooling of the shock and differ from steady-state shocks. The predicted column densities of different ions such as N+, C3+, and N4+, can be higher by up to several orders of magnitude compared to steady-state shocks. We also present some high-resolution emission spectra that can be compared with the observed remnants to obtain important information about the physical and chemical states of the remnant, as well as constrain the background interstellar medium.
Determination of strewn fields for meteorite falls
Authors: Moilanen Jarmo , Gritsevich Maria , Lyytinen Esko 
Published: February 2021

ABSTRACTWhen an object enters the atmosphere it may be detected as a meteor. A bright meteor, called a fireball, may be a sign of a meteorite fall. Instrumentally observed meteorite falls provide unique opportunities to recover and analyse unweathered planetary samples supplemented with the knowledge on the Solar system orbit they had. To recover a meteorite from a fireball event, it is essential that recovery teams can be directed to a well-defined search area. Until recently, simulations showing the realistic mapping of a strewn field were difficult, in particular due to the large number of unknowns not directly retrieved from the fireball observations. These unknowns include the number of fragments and their aerodynamic properties, for which the masses of the fragments need to be assumed in a traditional approach. Here, we describe a new Monte Carlo model, which has already successfully assisted in several meteorite recoveries. The model is the first of its kind as it provides an adequate representation of the processes occurring during the luminous trajectory coupled together with the dark flight. In particular, the model comprises a novel approach to fragmentation modelling that leads to a realistic fragment mass distribution on the ground. We present strewn field simulations for the well-documented Košice and Neuschwanstein meteorite falls, which demonstrate good matches to the observations. We foresee that our model can be used to revise the flux of extra-terrestrial matter onto the Earth, as it provides a possibility of estimating the terminal mass of meteorite fragments reaching the ground.
Gaia EDR3 in 6D: searching for unbound stars in the galaxy
Authors: Marchetti Tommaso 
Published: February 2021

ABSTRACT
The early third data release (EDR3) of the European Space Agency satellite Gaia provides coordinates, parallaxes, and proper motions for ∼1.47 billion sources in our Milky Way, based on 34 months of observations. The combination of Gaia DR2 radial velocities with the more precise and accurate astrometry provided by Gaia EDR3 makes the best data set available to search for the fastest nearby stars in our Galaxy. We compute the velocity distribution of ∼7 million stars with precise parallaxes, to investigate the high-velocity tail of the velocity distribution of stars in the Milky Way. We release a catalogue with distances, total velocities, and corresponding uncertainties for all the stars considered in our analysis1. By applying quality cuts on the Gaia astrometry and radial velocities, we identify a clean subset of 94 stars with a probability $P_\mathrm{ub}\gt 50 {{\ \rm per\ cent}}$ to be unbound from our Galaxy. In total, 17 of these have $P_\mathrm{ub}\gt 80{{\ \rm per\ cent}}$ and are our best candidates. We propagate these stars in the Galactic potential to characterize their orbits. We find that 11 stars are consistent with being ejected from the Galactic disc, and are possible hyper-runaway star candidates. The other six stars are not consistent with coming from a known star-forming region. We investigate the effect of adopting a parallax zero-point correction, which strongly impacts our results: when applying this correction, we identify only 12 stars with $P_\mathrm{ub}\gt 50{{\ \rm per\ cent}}$, 3 of these having $P_\mathrm{ub}\gt 80{{\ \rm per\ cent}}$. Spectroscopic follow-ups with ground-based telescopes are needed to confirm the candidates identified in this work.
At your ‘online’ service! A continuous service-learning program for college students during the COVID-19 pandemic
Authors: Vicente Niku E , Moredo Peter Jayson A , Cordero Dalmacito A 
Published: February 2021

Abstract
School health protocols in conducting face-to-face classes must be planned carefully to ensure that students will be safe from the effects of COVID-19. This is what the authors emphasized in a recent correspondence, which we re-echo in this paper in case the situation permits. However, a greater consideration must be given to colleges and universities where the aspect of community/social engagement of the students is already part of the curriculum. There is still a greater risk for students to go to the communities for service and social interaction. With this, we suggest that the service program can still continue through an enhanced electronic service-learning, which maximizes the human resources’ capacity and highlights students’ creativity with equally useful projects.
Epidermal growth factor receptor inhibitor-induced diarrhea: clinical incidence, toxicological mechanism, and management
Authors: Tao Gabriel , Chityala Pavan Kumar 
Published: February 2021

Abstract
The epidermal growth factor receptor (EGFR) family is a class of receptor tyrosine kinase playing a central role in carcinogenesis and cancer progression. The members of this family, particularly EGFR and human epidermal growth factor receptor 2 (HER2), are the most extensively studied drug targets for malignancy. Today, numerous tyrosine kinase inhibitors targeting EGFR family have been developed to combat non-small-cell lung cancer and breast cancer. However, severe gastrointestinal (GI) toxicity leading to dose reduction and treatment discontinuation hampers the therapeutic outcome of EGFR inhibitors. Diarrhea is one of the most frequent GI side effects, especially when it comes to second-generation EGFR inhibitors. Enterocytes apoptosis and increased inflammation accompany with many oral EGFR inhibitors. Loperamide and budesonide are the first-line treatment to manage such adverse effects. However, current prophylaxis and management are all empirical interventions to relieve the symptom. They do not specifically target the toxicological mechanism of EGFR inhibitors. Hereby, those anti-diarrhea agents do not work well when used in cancer patients experiencing EGFR inhibitor-induced diarrhea. On the other hand, the toxicological mechanism of EGFR inhibitor-induced diarrhea is poorly understood. Thus, determining the mechanism behind such diarrhea is urgently in need for developing genuinely effective anti-diarrhea agents. This review aims to call attention to EGFR inhibitor-induced diarrhea, a highly occurring and devastating cancer drug toxicity.
Community-Acquired Pressure Injuries in the Acute Care Setting
Authors: Singh Charleen , Shoqirat Noordeen 
Published: February 2021

ABSTRACT

OBJECTIVE
To explore the population of patients with a community-acquired pressure injury (CAPI) admitted to an acute care facility from December 2018 to December 2019. The specific aims of the study were to identify the (1) number of patients admitted with a CAPI, (2) type and frequency of pressure injury (PI), (3) location of residence prior to admission, (4) general demographics of the patient, and (5) condition of the PI at discharge.

METHODS
In this retrospective descriptive study, participants were identified and pulled from the hospital database at a 260-bed level 2 trauma center. Patients’ charts were identified by searching for nursing documentation of CAPIs. The exclusion criterion was charts that did not include verification of PI by a certified wound nurse. Data were pulled from the electronic medical record, verified by the certified wound nurse, and reviewed for participant demographics and implementation of PI prevention and treatment.

RESULTS
Over the course of the year, 88 patients had a CAPI. The majority lived at home (86.4%), were male (68.2%), and had stage 2 PIs (37%) on the sacrum (30.7%) or coccyx (51.1%). All participants had multiple comorbidities. Few PIs were from postacute care settings (11%) or another acute care hospital (1.1%). On average, patients had more than one PI. All patients had decreased or impaired mobility and mean body mass index of 26.38 ± 7.23 kg/m2. No one developed a new PI while in the acute care setting, and many of the CAPIs either healed (69.3%) or stabilized (22.7%).

CONCLUSIONS
Providers have an opportunity to make a difference in the prevalence of PIs occurring outside of acute and postacute care settings.
Postpartum Salpingectomy Compared With Standard Tubal Ligation After Vaginal Delivery
Authors: Wagar Matthew K. , Godecker Amy , Landeros Maria V. , Williams Makeba 
Published: February 2021

OBJECTIVE:
To compare operative outcomes of postpartum salpingectomy and tubal ligation after vaginal delivery.

METHODS:
This retrospective cohort study identified patients who underwent tubal sterilization between January 1, 2009, and December 31, 2019, at a large academic hospital, using the electronic medical record. All patients who delivered vaginally and underwent tubal sterilization during their delivery admissions were included. The primary outcome was total operative time. Secondary outcomes included estimated blood loss, perioperative complications, and readmission within 6 weeks postpartum. Patients who underwent bilateral tubal ligation were compared with those who underwent bilateral salpingectomy using Pearson's χ2 test, Fisher exact, and Student's t test.

RESULTS:
A total of 317 eligible patients were identified. One hundred and six (94%) salpingectomies were completed using a bipolar electrocautery device. Operative time was 3 minutes shorter in the salpingectomy group, 30 minutes (interquartile range 24–38) compared with 33.5 (26–42) minutes, P=.032. Patients who underwent salpingectomy were more likely to have estimated blood loss of 5 mL or less (our institutional shorthand for minimal blood loss) than women who underwent bilateral tubal ligation (78 [69%] vs 112 [55%], P=.015). There were no significant differences in perioperative complications between the groups.

CONCLUSION:
When using electrocautery, bilateral salpingectomy can be completed in the immediate postpartum period after vaginal delivery with equivalent operative times to bilateral tubal ligation.
Surgical Outcomes After Minimally Invasive Direct Lateral Corpectomy with Percutaneous Pedicle Screws for Osteoporotic Thoracolumbar Vertebral Collapse with Neurologic Deficits in the Thoracolumbar Spine Compared with Those After Posterior Spinal Fusion with Vertebroplasty
Authors: Ohba Tetsuro , Oba Hiroki , Oda Kotaro , Tanaka Nobuki , Haro Hirotaka 
Published: February 2021

Study Design.
Retrospective observational study of a cohort of consecutive patients.

Objective.
The aim of this study was to compare surgical invasion, mechanical complications, and clinical and radiological outcomes 2 years after surgery between minimally invasive corpectomy following percutaneous pedicle screw placements (X-core/PPS) and posterior fixation with vertebroplasty (VP) for treating osteoporotic vertebral fractures (OVFs), which failed conservative treatment due to neurological deficits.

Summary of Background Data.
Numerous studies have proposed surgical procedures to treat OVFs that fail conservative treatment. However, an optimal approach remains controversial because patients often have numerous comorbid medical complications, frequent instrumentation failure, and/or adjacent vertebral fracture (AVF). Recently, a minimally invasive lateral approach has attracted attention as an alternative procedure to the thoracolumbar junction for corpectomy and expandable cage replacement (X-Core Adjustable VBR System). However, its usefulness and validity is largely unknown.

Methods.
A cohort of 102 consecutive patients with OVF at T11–L1 who underwent surgery were followed up for >2 years after surgery. Ultimately 50 patients were included in the VP group and 45 in the X-core/PPS group. Surgical invasion, radiological examinations, and clinical outcomes between two procedures were compared.

Results.
Both X-core/PPS and VP procedures were safe and acceptable for neurological improvement and surgical invasion. The correction loss of local kyphotic angle (LKA) and occurrence of AVF were significantly less in the X-core/PPS group. Oswestry Disability Index in the X-core/PPS group at 2 years after surgery showed better recovery than that in the VP group, and no revision surgery was needed in the X-core/PPS group. Postoperative correction loss of LKA increased significantly when intraoperative endplate injury developed.

Conclusion.
This next-generation minimally invasive anterior and posterior combined surgery was found to be a safe and useful procedure for OVF treatment to reduce correction loss, mechanical complication, and AVF, resulting in less postoperative low back pain.

Level of Evidence: 3
Ultrasonic Bone Scalpel (USBS) Does Not Reduce Blood Loss During Posterior Spinal Fusion (PSF) in Patients with Adolescent Idiopathic Scoliosis (AIS)
Authors: Garg Sumeet , Thomas James , Darland Hannah , Kim Eun , Kittelson John , Erickson Mark , Carry Patrick 
Published: February 2021

Study Design
Randomized Clinical Trial.

Objective
The aim of this study was to compare the efficacy of USBS with standard-of-care surgical instruments during posterior spinal fusion (PSF) in patients with adolescent idiopathic scoliosis (AIS) by evaluating the difference in estimated blood loss per level fused (EBL/level).

Summary of Background Data
PSF surgery for AIS is often associated with high blood loss. Use of an ultrasonic bone scalpel (USBS) has been proposed to reduce blood loss during scoliosis surgery.

Methods
This was a single-blinded (patient-blinded), randomized, controlled superiority trial. We randomized 66 patients with AIS undergoing PSF to the control group (osteotome) or the experimental group (USBS). The primary outcome was intraoperative EBL/level obtained from red blood cell salvage reports. One-year follow-up was available for 57 of 62 (92%) of patients.

Results
EBL/level averaged 35 and 39 mL/level in the experimental and control groups, respectively [adjusted mean difference USBS – osteotome −8 mL/level, 95% CI: −16.4 to 0.3 mL/level, P = 0.0575]. There was no difference in curve correction [adjusted mean difference: −1.7%, 95% CI: −7.0 to 3.6%, P = 0.5321] or operative time [adjusted mean difference: −3.55 minutes, 95% CI: −22.45 to 15.46 min, P = 0.7089] between groups. Complications requiring change in routine postoperative care were noted in eight patients: two occurred in patients assigned to the experimental group and six occurred in patients assigned to the control group.

Conclusion
There was no clinically significant difference in total blood loss, EBL/level, or complications between the two groups. In contrast to reports from other centers, at our high-volume spine center, USBS did not lead to reduced blood loss during PSF for AIS. These results may not be generalizable to centers with longer baseline operative times or higher baseline average blood loss during PSF for AIS.

Level of Evidence: 1
Assessment of the Minimum Clinically Important Difference in the Smartphone-based 6-minute Walking Test After Surgery for Lumbar Degenerative Disc Disease
Authors: Zeitlberger Anna M. , Sosnova Marketa , Ziga Michal , Regli Luca , Bozinov Oliver , Weyerbrock Astrid , Stienen Martin N. , Maldaner Nicolai 
Published: February 2021

Study Design.
Prospective cohort study.

Objective.
The aim of this study was to determine the minimum clinically important difference (MCID) of the 6-minute walking test (6WT) after surgery for lumbar degenerative disc disease (DDD).

Summary of Background Data.
The smartphone-based 6WT is a valid and reliable tool to quantify objective functional impairment in patients with lumbar DDD. To date, the MCID of the 6WT has not been described in patients with DDD.

Methods.
We assessed patients pre- and 6-weeks postoperatively, analyzing both raw 6-minute walking distances (6WD; in meters) and standardized 6WT z scores. Three methods were applied to compute MCID values using established patient-reported outcomes measures (PROMs) as anchors (VAS back/leg pain, Zurich Claudication Questionnaire [ZCQ], Core Outcome Measures Index [COMI]): average change, minimum detectable change, and the change difference approach.

Result.
We studied 49 patients (59% male) with a mean age of 55.5 ± 15.8 years. The computation methods revealed MCID values ranging from 81 m (z score of 0.9) based on the VAS back pain to 99 m (z score of 1.0) based on the ZCQ physical function scale. The average MCID of the 6WT was 92 m (z score of 1.0). Based on the average MCID of raw 6WD values or standardized z scores, 53% or 49% of patients classified as 6-week responders to surgery for lumbar DDD, respectively.

Conclusion.
The MCID for the 6WT in lumbar DDD patients is variable, depending on the calculation technique. We propose a MCID of 92m (z score of 1.0), based on the average of all three methods. Using a z score as MCID allows for the standardization of clinically meaningful change and attenuates age- and sex-related differences.

Level of Evidence: 3
Fracture of the Dens Axis Due to Spinal Manifestation of Sarcoidosis
Authors: Eid Kevin , Friedrich Michael , Kudlek Claudia , Huenerlituerkoglu Ali , Schultz Johannes , Kraft Clayton N. 
Published: February 2021

Study Design
Case report and literature review.

Objective
We present a case of a pathologic unstable fracture of the odontoid process due to vertebral osseous sarcoidosis. The surgical management of this unreported pathology is described and a review of the literature is given.

Summary of Background Data
Sarcoidosis is a chronic inflammatory systemic disease of unknown etiology, characterized by multiorgan noncaseating granulomatous infiltrations. It affects primarily the lungs, lymphatic system, eyes, skin, heart, and nervous system. Osseous sarcoidosis is usually clinically asymptomatic and therefore frequently under-diagnosed. When it does affect the skull or vertebral column, specific surgical therapy is only necessary in cases with nonmanageable pain or where structural integrity is threatened.

Methods
Our patient underwent a so-called semiconservative approach, consisting of a minimally invasive transoral-transpharyngeal approach, surgical debridement of the lytic bony lesion, transplantation of cancellous homologous bone, and carbon chest halo-immobilization. Halo-immobilization was left for 8 weeks, followed by a further 6 weeks with a hard cervical collar.

Results
Routine computed tomography scans 3 days, 6, 12, 18 weeks, and 1 year after surgery showed good filling of the original defect with cancellous bone, correct alignment of the upper cervical spine, and progressive fracture consolidation and stability. Surgical site infection (SSI) was not observed. The patient had no neurological postoperative deficits. After initial dysphagia, swallowing was not permanently impaired.

Conclusion
Sarcoidosis-induced odontoid fractures can be managed successfully using a semiconservative approach, consisting of transoral-transmucosal, minimally invasive surgical procedure for debridement of the lesion and transplantation of cancellous bone with additional halo-immobilization. Permanent fusion of C1-2 with loss of the cervical range of motion is avoided. Despite performing bone surgery in a potentially markedly contaminated site, bacterial infection was not an issue, possibly supported by the temporary discontinuation of immunosuppressive agents and the prudent use of antibiotics.

Level of Evidence: 4