bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epigenomics and immunotherapeutic advances in pediatric brain tumors
Authors: Abedalthagafi Malak , Mobark Nahla , Al-Rashed May , AlHarbi Musa 
Published: April 2021

AbstractBrain tumors are the leading cause of childhood cancer-related deaths. Similar to adult brain tumors, pediatric brain tumors are classified based on histopathological evaluations. However, pediatric brain tumors are often histologically inconsistent with adult brain tumors. Recent research findings from molecular genetic analyses have revealed molecular and genetic changes in pediatric tumors that are necessary for appropriate classification to avoid misdiagnosis, the development of treatment modalities, and the clinical management of tumors. As many of the molecular-based therapies developed from clinical trials on adults are not always effective against pediatric brain tumors, recent advances have improved our understanding of the molecular profiles of pediatric brain tumors and have led to novel epigenetic and immunotherapeutic treatment approaches currently being evaluated in clinical trials. In this review, we focus on primary malignant brain tumors in children and genetic, epigenetic, and molecular characteristics that differentiate them from brain tumors in adults. The comparison of pediatric and adult brain tumors highlights the need for treatments designed specifically for pediatric brain tumors. We also discuss the advancements in novel molecularly targeted drugs and how they are being integrated with standard therapy to improve the classification and outcomes of pediatric brain tumors in the future.
Deep learning model to predict fracture mechanisms of graphene
Authors: Lew Andrew J. , Yu Chi-Hua , Hsu Yu-Chuan , Buehler Markus J. 
Published: April 2021

AbstractUnderstanding fracture is critical to the design of resilient nanomaterials. Molecular dynamics offers a way to study fracture at an atomistic level, but is computationally expensive with limitations of scalability. In this work, we build upon machine-learning approaches for predicting nanoscopic fracture mechanisms including crack instabilities and branching as a function of crystal orientation. We focus on a particular technologically relevant material system, graphene, and apply a deep learning method to the study of such nanomaterials and explore the parameter space necessary for calibrating machine-learning predictions to meaningful results. Our results validate the ability of deep learning methods to quantitatively capture graphene fracture behavior, including its fractal dimension as a function of crystal orientation, and provide promise toward the wider application of deep learning to materials design, opening the potential for other 2D materials.
Parallel G-quadruplexes recruit the HSV-1 transcription factor ICP4 to promote viral transcription in herpes virus-infected human cells
Authors: Frasson Ilaria , Soldà Paola , Nadai Matteo , Lago Sara , Richter Sara N. 
Published: April 2021

AbstractG-quadruplexes (G4s) are four-stranded nucleic acid structures abundant at gene promoters. They can adopt several distinctive conformations. G4s have been shown to form in the herpes simplex virus-1 (HSV-1) genome during its viral cycle. Here by cross-linking/pull-down assay we identified ICP4, the major HSV-1 transcription factor, as the protein that most efficiently interacts with viral G4s during infection. ICP4 specific and direct binding and unfolding of parallel G4s, including those present in HSV-1 immediate early gene promoters, induced transcription in vitro and in infected cells. This mechanism was also exploited by ICP4 to promote its own transcription. Proximity ligation assay allowed visualization of G4-protein interaction at the single selected G4 in cells. G4 ligands inhibited ICP4 binding to G4s. Our results indicate the existence of a well-defined G4-viral protein network that regulates the productive HSV-1 cycle. They also point to G4s as elements that recruit transcription factors to activate transcription in cells.
A discontinuity in the luminosity–mass relation and fluctuations in the evolutionary tracks of low-mass and low-metallicity stars at the Gaia M-dwarf gap
Authors: Mansfield Santana , Kroupa Pavel 
Published: April 2021

Context. The Gaia M-dwarf gap is a recently discovered feature in the colour-magnitude diagram that shows a deficiency of low-mass and low-metallicity stars at the lower end of the main sequence.
Aims. We aim at performing theoretical stellar modelling at low metallicities using a fine mass step and a fine time step, looking specifically for the transition of models from partially to fully convective since the convective kissing instability that occurs at this transition is believed to be the cause of the gap.
Methods. Stellar evolution models with metallicities of Z = 0.01, Z = 0.001, and Z = 0.0001 are performed using MESA, with a mass step of 0.00025 M⊙ and a time step of 50 000 years.
Results. The small time step produced models that experience loops in their evolutionary tracks in the Hertzsprung-Russell (HR) diagram. The fluctuations in effective temperature and luminosity correspond to repeated events in which the bottom of the convective envelope merges with the top of the convective core, transporting 3He from the core to the surface. In addition to the episodes of switching from partially to fully convective, several near-merger events that produced low amplitude fluctuations were also found. Low-metallicity models undergo the convective kissing instability for longer portions of their lifetime and with higher fluctuation amplitudes than models with higher metallicities. The small mass step used in the models revealed a discontinuity in the luminosity–mass relation at all three metallicities.
Conclusions. The repeated merging of the convective core and envelope, along with several near-merger events, removes an abundance of 3He from the core and temporarily reduces nuclear burning. This results in fluctuations in the model’s luminosity and effective temperature, causing loops in the evolutionary track in the HR diagram and leading to the deficiency of stars at the M-dwarf gap, as well as a discontinuity in the luminosity–mass relation.
A systematic search for changing-look quasars in SDSS-II using difference spectra
Authors: Potts B. , Villforth C. 
Published: April 2021

Context. ‘Changing-look quasars’ (CLQs) are active galactic nuclei (AGN) showing extreme variability that results in a transition from type 1 to type 2 AGN. The short timescales of these transitions present a challenge to the unified model of AGN and the physical processes causing these transitions remain poorly understood. CLQs also provide interesting samples for the study of AGN host galaxies since the central emission disappears almost entirely.
Aims. Previous searches for CLQs have utilised photometric variability or SDSS classification changes to systematically identify CLQs; this approach may miss lower luminosity CLQs. In this paper, we aim to use spectroscopic data to asses if analysis difference spectra can be used to detect further CLQs that have been missed by photometric searches.
Methods. We searched SDSS-II DR 7 repeat spectra for sources that exhibit either a disappearance or appearance of both broad line emission and accretion disc continuum emission by directly analysing the difference spectrum between two epochs of observation.
Results. From a sample of 24 782 objects with difference spectra, our search yielded six CLQs within the redshift range 0.1 ⩽ z ≤ 0.3, including four newly identified sources. Spectral analysis indicates that changes in the accretion rate can explain the changing-look behaviour. While a change in dust extinction fits the changes in the spectral shape, the timescales of the changes observed are too short for obscuration from torus clouds.
Conclusions. Using difference spectra was shown to be an effective and sensitive way to detect CLQs. We recover CLQs an order of magnitude lower in luminosities than those found by photometric searches and achieve higher completeness than spectroscopic searches relying on pipeline classification.
Seltene Erkrankungen der Nase, der Nasennebenhöhlen und der vorderen Schädelbasis
Authors: Sommer Fabian 
Published: April 2021

ZusammenfassungSeltene Erkrankungen der Nase, der Nasennebenhöhlen und der vorderen Schädelbasis stellen aufgrund der niedrigen Inzidenz und den daraus resultierend eingeschränkten diagnostischen Kriterien sowie therapeutischen Optionen eine Herausforderung dar. Der Schwellenwert, ab dem eine Erkrankung als selten zu werten ist, liegt bei höchstens 5 Betroffenen pro 10 000 Personen. Innerhalb dieser Erkrankungen gibt es allerdings extreme Schwankungen. So gehören einige seltene Erkrankungen, wie z.B. das invertierte Papillom, zu den regelmäßig diagnostizierten und therapierten Krankheitsbildern einer größeren Klinik für Hals-Nasen-Ohrenheilkunde. Andererseits liegen bei anderen seltenen Erkrankungen und Fehlbildungen weltweit deutlich unter 100 Fallberichte vor, was die Notwendigkeit einer Bündelung der verfügbaren Erfahrung zu Diagnostik und Therapie unterstreicht.Die vorliegende Arbeit gibt eine Übersicht zu seltenen Erkrankungen der Nase, der Nasennebenhöhlen und der vorderen Schädelbasis aus den übergeordneten Bereichen Erkrankungen / Syndrome des olfaktorischen Systems, Fehlbildungen der Nase und Nasennebenhöhlen, Belüftungs- und Funktionsstörungen sowie benigne und maligne Tumore. Die Einordnung sowie Angaben zu Diagnostik und Therapiemöglichkeiten wurden unter Berücksichtigung der aktuellen Literatur erstellt.
Seltene Erkrankungen der Mundhöhle, des Halses und des Pharynx
Authors: Reichel Christoph A. 
Published: April 2021

ZusammenfassungErkrankungen, welche mit einer Häufigkeit von weniger als 1–10 Fällen pro 10 000 Personen in der Bevölkerung auftreten, gelten als selten. Derzeit sind zwischen 5000 und 8000 seltene Krankheiten bekannt, jedes Jahr werden etwa 250 seltene Krankheitsbilder neu beschrieben. Eine Vielzahl dieser Pathologien betrifft den Kopf-Halsbereich. Für die Diagnosestellung einer seltenen Erkrankung bedarf es oftmals langer Zeit. Das Leben betroffener Patientinnen und Patienten ist häufig von Arztbesuchen und Krankenhausaufenthalten geprägt. Die meisten seltenen Krankheiten besitzen eine genetische Ursache und sind trotz des medizinischen Fortschritts bis heute unheilbar. In den letzten Jahren sind jedoch die Wahrnehmung und das Wissen von bzw. zu seltenen Krankheitsbildern unter anderem durch die Schaffung von öffentlich zugänglichen Datenbanken gestiegen, die Etablierung von Selbsthilfegruppen hat zudem die Mündigkeit Betroffener gestärkt. Seit kurzem erlauben nun neuartige technische Errungenschaften im biomedizinischen Bereich genetische Ursachen seltener Erkrankungen bei einzelnen Patientinnen und Patienten individuell zu charakterisieren. Auf Grundlage dessen sollte es in naher Zukunft möglich werden, im Sinne der translationalen und personalisierten Medizin maßgeschneiderte Behandlungskonzepte für Patientinnen und Patienten mit seltenen Krankheiten zu erarbeiten. Mit dem vorliegenden Referat, welches sich mit seltenen Erkrankungen von Lippe, Mundhöhle, Pharynx und Halsweichteilen beschäftigt, soll ein Beitrag zu diesen Entwicklungen geleistet werden. Den Leserinnen und Lesern wird dabei ein kompakter Überblick zu einer Auswahl diesen anatomischen Bereich betreffender Krankheitsbilder gegeben. Verweise auf weiterführende Informationen für das medizinische Fachpersonal und betroffene Patientinnen und Patienten unterstützen die weitere Vertiefung ihres Wissens und führen gezielt zum aktuellen Kenntnisstand in diesem hoch-dynamischen Themengebiet.
Embryologie, Fehlbildungen und seltene Erkrankungen der
Cochlea
Authors: Warnecke Athanasia , Giesemann Anja 
Published: April 2021

ZusammenfassungAuch wenn die einzelnen Krankheitsbilder selten sind, stellen seltene
Erkrankungen der Cochlea in ihrer Gänze eine doch gehäufte
Entität dar, die zu Hörstörungen führt.
Ein/Das Ziel des vorliegenden Referates war es, unter
Berücksichtigung der Embryonalentwicklung der Hörschnecke
und einer systematischen Zusammenfassung eine übersichtliche
Darstellung der seltenen cochleären Erkrankungen zu
ermöglichen. Auch wenn rapide biotechnologische und bioinformatische
Fortschritte die Diagnose einer seltenen Erkrankung erleichtern, so kann oft
nur im interdisziplinären Austausch der Verdacht einer seltenen
Erkrankung erhoben werden. Trotz gleicher zugrunde liegender Mutationen kann
der Phänotyp nicht nur bei den genetisch bedingten
Hörstörungen sondern auch bei den syndromalen Erkrankungen
stark variieren. Schließlich wird deutlich, dass der
Phänotyp der einzelnen seltenen Erkrankungen nicht
ausschließlich durch die klassische Genetik bestimmt werden
kann.
The Lucerne Protocol for the Production of Autologous Serum Eyedrops
Authors: Sanak Frantisek , Baenninger Philipp , Kaufmann Claude , Iselin Katja , Bachmann Lucas , Buhl Daniela , Thiel Michael 
Published: April 2021

Abstract
Background There are a variety of protocols for manufacturing autologous serum (AS) eye drops. The Lucerne protocol for the production of AS eye drops uses a slightly reduced gravitational (g)-force and time for the centrifugation process (2500 × g for 10 minutes), compared to previously published optimised protocols, to obtain high levels of epitheliotropic growth factors (3000 × g for 15 minutes). The goal of this study was to compare the concentrations of growth factors, albumin and lysozyme in autologous serum eye drops manufactured with these protocols.
Material and Methods Blood from 5 healthy volunteers was placed in plastic tubes without an anticoagulant. Tubes from each donor were left in a vertical position for 2 hours at room temperature to facilitate coagulation, followed by centrifugation at either 2500 × g for 10 minutes or at 3000 × g for 15 minutes at room temperature. The serum levels of beta nerve growth factor (β-NGF), transforming growth factor β1 (TGF-β1), epidermal growth factor (EGF), hepatocyte growth factor (HGF), platelet-derived growth factor BB (PDGF-BB) and vascular endothelial growth factor A (VEGF-A) were measured in triplicate with a multi-analyte Simple Plex platform. The Simple Plex cartridge allows each sample to be run in triplicate for each analyte and prevents any interaction between the antibody components for each biomarker. The serum level of albumin was measured by turbidimetric immunoassay Tina-quant and of lysozyme by single radial immunodiffusion assay.
Results For all analytes, the reduced g-force and centrifugation time did not result in a significant difference in serum levels.
Conclusions The Lucerne protocol for the production of autologous serum eye drops with reduced g-force and a shorter centrifugation time does not affect the concentrations of the main epitheliotropic growth factors, albumin and lysozyme, in AS eye drops.
Copper-Catalyzed Oxydifluoroalkylation of β,γ-Unsaturated Oximes for the Construction of Isoxazolines with a Difluoroalkyl Side Chain
Authors: Wang Guangwei , Wang Lianxin , Chen Hongtai , Zhao Wentao 
Published: April 2021

AbstractA copper-catalyzed oxydifluoroalkylation of β,γ-unsaturated oximes has been developed. This reaction proceeded through a cascade of difluoroalkylation of alkene followed by a nucleophilic attack of the hydroxyl group of oximes. This protocol features mild reaction conditions, low-cost catalyst, and broad substrate scope, which provides a facile method to synthesize isoxazolines with a fluorinated side chain
Pseudoaneurysm following Surgical Resection of Craniopharyngioma: What Is the Best Management?
Authors: del Pont Francisco Marco , Villalonga Juan Francisco , Sáenz Amparo , Caffaratti Guido , Alcorta Santiago Condomi , Cervio Andrés 
Published: April 2021

AbstractCraniopharyngiomas are benign tumors of the sellar and parasellar region for which surgical resection remains the treatment of choice. There are many publications on the most frequent postoperative complications, but few reports on subclinical lesions affecting the arteries of the circle of Willis, despite their high morbidity and mortality rate. Trauma-induced aneurysms are infrequent, representing less than 1% of intracranial aneurysms. Iatrogenic intracranial pseudoaneurysms are a subtype of surgically induced aneurysms developed as a result of direct injury to the arterial wall or after dissection of tumors adherent to the vessel adventitia. The natural history of these lesions is not well known because their incidence is extremely low. We report two cases of postoperative aneurysms of the internal carotid artery after craniopharyngioma resection and a brief review on the management of such lesions.
Perioperative Practices and Outcome of Neurosurgery during the COVID-19 Pandemic: Institutional Experience and Retrospective Observational Analysis
Authors: Khurana Priyanka , Ganjoo Pragati , Duggal Sakshi , Kiro Kiran Lata , Dhanwani Lavina , Tandon Monica S. , Singh Daljit , Jagetia Anita 
Published: April 2021

AbstractIntroduction Surgery during the coronavirus disease 2019 (COVID-19) pandemic is a major concern due to possibility of infection transmission among health care workers (HCWs) and patients, and a worsened surgical outcome; most surgeries are thus being deferred. However, we continued with emergency neurosurgeries using our own Neurosurgical Standard Operating Procedures (NS-SOPs). We describe here our institutional neurosurgical experience and observations of a retrospective analysis done to determine the incidence of workplace-acquired COVID infection among the HCWs, and the outcome of neurosurgery performed during the early phase of the on-going pandemic.Methods Our NS-SOPs included a Screening Proforma, and protocols for the conduct of neurosurgery, starting from the preoperative period till death or postdischarge follow-up of the patients. Protocols to ensure safety and mental well-being of the HCWs were also implemented. Patient and HCW data from April 1 to August 31, 2020 was collected and analyzed for the postsurgical patient outcome and for determining the level of workplace-transmitted COVID infection.Results Neurosurgeries were performed on 169 patients during this 5-month period. We observed a cumulative mortality of 17/169 (10.1%), with 5 patients having unexplained postoperative respiratory manifestations and rapid deterioration suggestive of COVID illness. Nineteen HCWs (8.83%), mostly nurses, were infected, but only 3 (16.7%) had workplace-acquired infection. The infections were sporadic with no cluster of infections observed.Conclusion Implementation of standard perioperative protocols and their continuous scrutiny, evaluation, and modification is important to contain infection in HCWs and to improve the neurosurgical outcome during this pandemic.
Diagnostic Value of MRI and Radiographs of the Knee to Identify Osteochondral Lesions in Acute Patellar Instability
Authors: Baker Hayden , Dickherber Jason , Reddy Manoj , Rizzi Andrew , Kahn Adam , Athiviraham Aravind 
Published: April 2021

AbstractThe purpose of this study was to define the diagnostic value of magnetic resonance imaging (MRI) and plain radiographs (X-ray [XR]) in identifying an osteochondral defect or loose body in patients undergoing operative treatment for patellar instability. A total of 87 patients treated operatively for patellar instability with medial patellofemoral ligament (MPFL) reconstruction between 2015 and 2019 were identified. Inclusion criteria were evidence of clinical patellar instability, preoperative XR and MRI studies, and concomitant diagnostic knee arthroscopy and MPFL reconstruction performed to address patellar instability. Patients were excluded if they had a history of prior procedure for patellar instability on the surgical knee, underwent MPFL reconstruction without concomitant diagnostic knee arthroscopy, or had an anterior cruciate ligament or posterior cruciate ligament deficient knee. Operative notes and arthroscopic images were reviewed to identify osteochondral or chondral injuries and loose bodies noted during diagnostic arthroscopy. The primary outcome was the identification of intra-articular loose bodies, chondral injury, or osteochondral defect on preoperative plain radiographs and MRI in patients with patellar instability. All MRIs were performed on a 3T MRI. The sensitivity and specificity of identifying loose bodies on MRI were 0.52 and 0.92 and on XR were 0.23 and 0.98, respectively. The sensitivity and specificity of identifying osteochondral lesions on MRI were 0.43 and 0.81 and on XR were 0.08 and 0.97, respectively. Of the 87 available reports, 45 (51%) described performing chondroplasty for Outerbridge grade II/III chondral lesions on diagnostic arthroscopy. In conclusion, MRI and XR are poorly sensitive at identifying loose bodies or osteochondral defects after patellar dislocations. The poor sensitivity of imaging studies must be considered when determining whether or not to recommend operative management to a patient with patellar instability. This is a Level IV, diagnostic study.
A direct link between active matter and sheared granular systems
Authors: Morse Peter K. , Roy Sudeshna , Agoritsas Elisabeth , Stanifer Ethan , Corwin Eric I. , Manning M. Lisa 
Published: April 2021

Significance
There is not yet a robust theoretical framework predicting the dynamics of dense active matter, where energy is injected at the scale of constituent particles. Previous work has shown that some features of dense active matter are similar to those in dense disordered materials that are sheared globally from the boundaries. Using analytic and computational tools, we show that there is a direct correspondence between active matter and applied shear strain, which can in turn be used to help predict the behavior of dense active matter.
Interferometric visibility in curved spacetimes
Authors: Basso Marcos L W , Maziero Jonas 
Published: April 2021

Abstract
In (Zych et al 2011 Nat. Commun.
2 505), the authors predicted that the interferometric visibility is affected by a gravitational field in way that cannot be explained without the general relativistic notion of proper time. In this work, we take a different route and start deriving the same effect using the unitary representation of the local Lorentz transformation in the Newtonian limit. In addition, we show that the effect on the interferometric visibility due to gravity persists in different spacetime geometries. However, the influence is not necessarily due to the notion of proper time. For instance, by constructing a ‘astronomical’ Mach–Zehnder interferometer in the Schwarzschild spacetime, the influence on the interferometric visibility can be due to another general relativistic effect, the geodetic precession. Besides, by using the unitary representation of the local Lorentz transformation, we show that this behavior of the interferometric visibility is general for an arbitrary spacetime, provided that we restrict the motion of the quanton to a two-dimensional spacial plane.
Quantitative experiments in a distance lab: studying blackbody radiation with a smartphone
Authors: Onorato Pasquale , Rosi Tommaso , Tufino Eugenio , Caprara Caterina , Malgieri Massimiliano 
Published: April 2021

Abstract
In this paper we present an experiment aimed at investigating the thermal radiation law. The spectrum of a filament light bulb is acquired at different temperatures using a low-cost grating spectrometer based on a smartphone camera, while the measurement of filament temperature is obtained indirectly from the temperature dependence of the filament resistance. Two different methods for measuring the light intensity are tested: one is based on the use of the ambient light sensor of a smartphone, the other on a home-made grating spectrometer coupled with the smartphone camera. We observe a good agreement of the experimental data with the theoretical predictions of the Planck distribution in the limit of the Wien approximation restricted to the wavelength range characterizing the response of the smartphone light sensor and camera.