bluuebunny/crossref_metadata_2025 huggingface dataset:
Design und Evaluation eines Prüf-Studierenden-Kurses für studentische prospektive Multicenterstudien – ein CHIR-Net-SIGMA-Projekt zum forschenden Lernen
Authors: Rädeker Lukas , Schwab Marius , Frey Pia Elena , Friedrich Mirco , Sliwinski Svenja , Steinle Julia , Fink Christoph A. , Leuk Alexander , Ganschow Petra , Ottawa Gregor Benedikt , Klose Christina , Feißt Manuel , Dörr-Harim Colette , Tenckhoff Solveig , Mihaljevic André L.
Published: October 2019

Hintergrund Die Vermittlung wissenschaftlicher Kompetenzen im Medizinstudium ist mangelhaft. Dies setzt sich in der Weiterbildung fort und führt zunehmend zu einem Mangel an wissenschaftlich tätigen Ärzten. Das chirurgische Studiennetzwerk (CHIR-Net) hat ein studentisches Forschungsnetzwerk gegründet (SIGMA, Student-initiated German Medical Audit), um dem entgegenzuwirken. Ziel dieser Arbeit ist es, die Entwicklung, Umsetzung und Evaluation eines Prüf-Studierenden-Kurses (PSK) zu beschreiben, der Studierende zur eigenständigen Durchführung von klinischen Studien befähigen soll.

Material und Methoden Anhand des Kernzyklus wurde ein 3-gliedriges Curriculum entwickelt, das aus Onlinetutorien, einer Wochenendpräsenzphase sowie einer Nachbereitungsperiode besteht. Die Lernziele wurden anhand der Bloom-Taxonomie des Wissens definiert. Die Lehrinhalte richteten sich nach Vorgaben der Koordinierungszentren für Klinische Studien (KKS-Netzwerk) und der Bundesärztekammer für ärztliche Prüferkurse sowie studienrelevanten Inhalten. Eine große Bandbreite an verschiedenen Lehrmethoden sowie Prüfungsformaten wurde eingesetzt. Durch Einbindung studienrelevanter Berufsgruppen wurde eine enge Verzahnung mit den Studierenden gewährleistet. Der Wissenszuwachs wurde anhand eines Multiple-Choice-Prä-Post-Tests evaluiert. Die Evaluation der Zufriedenheit der Studierenden erfolgte mittels einer 5-Punkte-Likert-Skala, wobei 5 eine volle Zustimmung markierte.

Ergebnisse Der erste SIGMA-PSK wurde im Frühjahr 2018 erfolgreich implementiert. Die Präsenzphase fand im Februar 2018 mit 32 Studierenden aus 13 Standorten statt, wobei die Studierenden aus unterschiedlichen Semestern kamen. Im Mittel wurden im Prä-Test 53,8 ± 8,3% der Fragen korrekt beantwortet vs. 71,2 ± 7,2% im Post-Test (p < 0,0001). Die größte individuelle Verbesserung des Testergebnisses betrug 30%, die geringste Differenz zum Prä-Test 5%. Subjektive Evaluationsergebnisse des Kurses waren durchweg positiv mit einem durchschnittlichen Ergebnis von 4,63 ± 0,34 auf der 5-Punkte-Likert-Skala.

Schlussfolgerung Eine Ausbildung von Medizinstudierenden in den Grundlagen klinischer Studien ist machbar. Ein kompakter PSK kann unter dem Einsatz moderner Lehrdidaktik die Studierenden auf die eigenständige Durchführung klinischer Studien vorbereiten.
Umfrage zum Bedarf einer e-Learning-Plattform für Ärzte in der HNO-Facharzt-Weiterbildung
Authors: Shabli Sami , Heuermann Katharina , Leffers David , Kriesche Franziska , Abrams Nils , Yilmaz Murat , Klußmann Jens Peter , Guntinas-Lichius Orlando , Beule Achim
Published: October 2019

Hintergrund Interaktive e-Learning-Plattformen werden in Zukunft das klassische Lehrbuch ersetzen und das Lernen verändern. Diese Plattformen können neben Texten und Abbildungen auch Videosequenzen und Audioaufnahmen umfassen. Ein solches Medium speziell für die HNO-Heilkunde existiert aktuell nicht. Bisher ist der tatsächliche Bedarf von HNO-Assistenzärzten und deren Vorstellung von den Leistungen einer solchen Plattform unklar.

Material und Methoden Eine Online-Umfrage mit 17 Fragen wurde von HNO-Ärzten entwickelt, die weiterbilden und regelmäßig Weiterbildungen besuchen. An alle HNO-Assistenzärzte in Deutschland, die der Deutschen Akademie für Hals-Nasen-Ohrenheilkunde, Kopf- und Halschirurgie, bekannt waren, wurde die Umfrage im April und Mai 2019 per E-Mail versandt.

Ergebnisse An der Studie nahmen insgesamt 150 von 671 HNO-Ärzten und Assistenzärzten teil (Rücklaufquote: 22 %). Davon waren 80 % Assistenzärzte und 20 % bereits HNO-Fachärzte. 63–80 % der Befragten nutzen Online-Medien bereits am Arbeitsplatz zur Vorbereitung auf die HNO-Fachprüfung, zu Weiterbildungszwecken und zur Unterstützung im klinischen Alltag. 92–95 % der Teilnehmer erklärten, eine interaktive Plattform für die Vorbereitung und Weiterbildung zum HNO-Facharzt nutzen zu wollen. e-Learning-Medien werden von den Befragten zur Vorbereitung auf die HNO-Facharztprüfung bzw. im klinischen Alltag und zur Weiterbildung durchschnittlich 108 bzw. 130 min/Woche verwendet. Der Wunsch nach chirurgischen Lehrvideos ist sehr groß.

Schlussfolgerung Speziell für die HNO-Heilkunde gibt es einen hohen Bedarf an einer strukturierten e-Learning-Plattform. Eine interaktive e-Learning-Plattform würde eine qualifizierte Weiterbildung sicherstellen, ergänzen und unterstützen.
Nickel-Catalyzed Amination of α-Aryl Methyl Ethers
Authors: Patel Purvish , Rousseaux Sophie A. L.
Published: October 2019

α-Aryl amines are prevalent in pharmaceutically active compounds and natural products. Herein, we describe a Ni-catalyzed protocol for their synthesis from readily available α-aryl ethers. While α-aryl ethers have been used as electrophiles in Ni-catalyzed C–C bond formations, their use in C–heteroatom bond formation is much less prevalent. Preliminary mechanistic insight suggests that oxidative addition is facilitated by an anionic ligand and that reductive elimination is a reversible process.
Pictet–Spengler Synthesis of Perfluoroalkylated Tetrahydro-γ-carbolines and Tetrahydropyrrolopyrazines
Authors: Voznesenskaia Natalia G. , Shmatova Olga I. , Nenajdenko Valentine G.
Published: October 2019

A new method for the synthesis of perfluoroalkylated derivatives of γ-carboline and pyrrolopyrazine was elaborated. Pictet–Spengler reaction of isotryptamine and 2-(pyrrol-1-yl)ethanamine with trifluoromethylated carbonyls and 2-perfluoroalkyl-substituted five-, six-, and seven-membered cyclic imines was studied. It was found that this approach opens efficient access to a family of alkaloid-like compounds bearing a CF3 or C2F5 group in the structure. In the case of the iso-Pictet–Spengler reaction with 2-perfluoroalkyl-substituted cyclic imines, a series of γ-carbolines bearing an aminoalkyl group were prepared.
Azaheterocyclic Derivatives of ortho-Carborane: Synthetic Strategies and Application Opportunities
Authors: Smyshliaeva Lidiia A. , Varaksin Mikhail V. , Charushin Valery N. , Chupakhin Oleg N.
Published: October 2019

Azaheterocyclic derivatives of 1,2-dicarba-closo-dodeca­borane (ortho-carborane) are known to be of particular interest due to numerous plausible applications, particularly, in medicine, materials science, and advanced technologies. Three principal synthetic strategies resulting in azaheterocyclic carboranes, in which boron-enriched and azaheterocyclic fragments are linked to each other, either directly by means of the C–C bonds or through a short spacer (CH2, CH2S, CH2O, etc.), have been outlined. These synthetic approaches are of general character and can be used both individually and in combination to afford promising organoboron clusters of diverse architectures.

1 Introduction

2 C–C Cross-Coupling Strategies in the Synthesis of Azahetero­cyclic Carboranes

3 Carboryne-Based Transformation Strategies

4 Condensation Strategies: Reactions of Decaborane B10H14 with Substituted Acetylenes

5 Conclusion and Outlook
Growth and Nutrition in Cystic Fibrosis
Authors: Brownell Jefferson N. , Bashaw Hillary , Stallings Virginia A.
Published: October 2019

Optimal nutrition support has been integral in the management of cystic fibrosis (CF) since the disease was initially described. Nutritional status has a clear relationship with disease outcomes, and malnutrition in CF is typically a result of chronic negative energy balance secondary to malabsorption. As the mechanisms underlying the pathology of CF and its implications on nutrient absorption and energy expenditure have been elucidated, nutrition support has become increasingly sophisticated. Comprehensive nutrition monitoring and treatment guidelines from professional and advocacy organizations have unified the approach to nutrition optimization around the world. Newborn screening allows for early nutrition intervention and improvement in short- and long-term growth and other clinical outcomes. The nutrition support goal in CF care includes achieving optimal nutritional status to support growth and pubertal development in children, maintenance of optimal nutritional status in adult life, and optimizing fat soluble vitamin and essential fatty acid status. The mainstay of this approach is a high calorie, high-fat diet, exceeding age, and sex energy intake recommendations for healthy individuals. For patients with exocrine pancreatic insufficiency, enzyme replacement therapy is required to improve fat and calorie absorption. Enzyme dosing varies by age and dietary fat intake. Multiple potential impediments to absorption, including decreased motility, altered gut luminal bile salt and microbiota composition, and enteric inflammation must be considered. Fat soluble vitamin supplementation is required in patients with pancreatic insufficiency. In this report, nutrition support across the age and disease spectrum is discussed, with a focus on the relationships among nutritional status, growth, and disease outcomes.
Foreign Body Inside the Tunnel: A Rare Cause of Acute Cubital Tunnel Syndrome
Authors: Yildiran Gokce , Sutcu Mustafa , Akdag Osman , Tosun Zekeriya
Published: October 2019

Foreign bodies are common entities found in hand surgery practice. However, they are a very rare cause of the acute cubital tunnel syndrome. A 48-year-old male patient was consulted for cubital tunnel symptoms after 2-day unconscious state in the intensive care unit. The ulnar nerve was explored, a piece of glass was removed inside the cubital tunnel, and the nerve was repaired. However, compression neuropathy symptoms due to the acute trauma are interesting. Nerve laceration with a foreign body should be considered in acute-onset cubital tunnel syndrome, in which the foreign body history of a trauma patient cannot be determined explicitly.
Longitudinally Measured Fibrinolysis Factors are Strong Predictors of Clinical Outcome in Patients with Chronic Heart Failure: The Bio-SHiFT Study
Authors: van den Berg Victor J. , Bouwens Elke , Umans Victor A. W. M. , de Maat Moniek , Manintveld Olivier C. , Caliskan Kadir , Constantinescu Alina A. , Mouthaan Henk , Cornel Jan-Hein , Baart Sara , Akkerhuis K. Martijn , Boersma Eric , Kardys Isabella
Published: October 2019

Objective This article investigates whether longitudinally measured fibrinolysis factors are associated with cardiac events in patients with chronic heart failure (CHF).

Methods A median of 9 (interquartile range [IQR] 5–10) serial, tri-monthly blood samples per patient were prospectively collected in 263 CHF patients during a median follow-up of 2.2 (IQR 1.4–2.5) years. Seventy patients (cases) reached the composite endpoint of cardiac death, heart failure hospitalization, left ventricular assist device, or heart transplantation. From all longitudinal samples, we selected baseline samples in all patients and the last two samples before the event in cases or the last sample available in event-free patients. Herein, we measured plasminogen activator inhibitor 1 (PAI-1), tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA), and soluble urokinase plasminogen activator surface receptor (suPAR). Associations between temporal biomarker patterns during follow-up and the cardiac event were investigated using a joint model.

Results Cases were on average older and showed higher New York Heart Association class than those who remained event-free. They also had lower blood pressures, and were more likely to have diabetes, renal failure, and atrial fibrillation. Longitudinally measured PAI-1, uPA, and suPAR were independently associated with adverse cardiac events after correction for clinical characteristics (hazard ratio [95% confidence interval]) per standard deviation increase of 2.09 (1.28–3.45) for PAI-1, 1.91 (1.18–3.24) for uPA, and 3.96 (2.48–6.63) for suPAR. Serial measurements of tPA were not significantly associated with the event after correction for multiple testing.

Conclusion Longitudinally measured PAI-1, uPA, and suPAR are strongly associated with adverse cardiac events during the course of CHF. If future research confirms our results, these fibrinolytic factors may carry potential for improved, and personalized, heart failure surveillance and treatment monitoring.
Antiphospholipid Antibody Syndrome and Infertility
Authors: Rodrigues Vivian de Oliveira , Soligo Adriana de Góes e Silva , Pannain Gabriel Duque
Published: October 2019

Antiphospholipid antibody syndrome (APS) is a systemic, autoimmune, prothrombotic disease characterized by persistent antiphospholipid antibodies (aPLs), thrombosis, recurrent abortion, complications during pregnancy, and occasionally thrombocytopenia. The objective of the present study was to review the pathophysiology of APS and its association with female infertility. A bibliographic review of articles of the past 20 years was performed at the PubMed, Scielo, and Bireme databases. Antiphospholipid antibody syndrome may be associated with primary infertility, interfering with endometrial decidualization and with decreased ovarian reserve. Antiphospholipid antibodies also have direct negative effects on placentation, when they bind to the trophoblast, reducing their capacity for invasion, and proinflammatory effects, such as complement activation and neutrophil recruitment, contributing to placental insufficiency, restricted intrauterine growth, and fetal loss. In relation to thrombosis, APS results in a diffuse thrombotic diathesis, with global and diffuse dysregulation of the homeostatic balance. Knowing the pathophysiology of APS, which is closely linked to female infertility, is essential for new therapeutic approaches, specialized in immunomodulation and inflammatory signaling pathways, to provide important advances in its treatment.
Attitudes and Personal Attributes Regarding Patient Receptivity towards the Participation of Medical Students in Gynecological Consultations: A Cross-Sectional Study
Authors: Wanderley Miriam da Silva , Sobral Dejano Tavares , Lima Brenda Alves de Oliveira , Freire Maria Elisa de Bessa , Silva Mariana Albuquerque Campos da , Rosa Marina Prado e Silva Gonçalves , Souza Thaís Ferreira
Published: October 2019

Objective To evaluate the association between the acceptance on the part of the patients and their reasons to consent to or refuse medical student attendance during gynecological outpatient care, considering the participants' demographic characteristics, consultation experience, and gender bias or lack thereof.

Methods Face-to-face interviews with patients waiting for gynecological consultations that had been scheduled in advance at Hospital Universitário de Brasília. Contingency analyses were used to determine the levels of association among the patient variables. The accepted significance level was values of p < 0.05.

Results We interviewed 469 patients. The comfort level with the presence of a student was strongly related to the number of students present during the consultation (Cramér V = 0.671). The inclination to grant consent (a series of reasons to consent to or refuse student attendance) was significantly related (p < 0.001) to the overall receptivity to student participation (ρ = 0.482), the positive appraisal of student-doctor demeanor in previous consultations (ρ = 0.253, N = 408), and to greater levels of schooling (ρ = 0.158). The patients' receptivity was significantly related (p < 0.001) to the lack of bias regarding the gender of the physician (Cramér V = 0.388), previous experience with students (Cramér V = 0.235) and awareness of the fact that they would be present (Cramér V = 0.217), older age (ρ = 0.136, p = 0.003), and multiparity (ρ = 0.102, p = 0.027).

Conclusion Greater receptivity to student participation related significantly to five conditions in decreasing order of strength of association: lack of bias regarding the gender of the Ob-Gyn, previous experience with student involvement, awareness of the presence of students, older age, and multiparity. We also found that a more positive inclination to consent to student attendance correlated positively with a greater receptivity to student participation and to a suitable student-doctor demeanor.
Empowering Adolescent Mothers in the Choice of Contraceptive Methods at the Postpartum Period: Avoiding a Subsequent Pregnancy
Authors: Borovac-Pinheiro Anderson , Jesus Erica Almeida Ramos , Surita Fernanda Garanhani
Published: October 2019

Objective Almost 80% of adolescent pregnancies are unplanned, and between 28 and 63% of adolescent mothers had a repeated pregnancy within 18 months. Among girls with repeated pregnancies, two-thirds reported that the pregnancy was unplanned. We aim to assess contraceptive use by adolescent mothers with increasing choice for long-acting reversible contraception (LARC) methods in postpartum consultation after a semistructured group intervention involving adolescent mothers.

Methods Retrospective observational study conducted at the Universidade Estadual de Campinas, Campinas, state of São Paulo, Brazil, involving new antenatal and postpartum education groups for adolescents. At postpartum consultations, the adolescents chose their contraceptive. The data was compared with previous series followed in a period before the implementation of the education group – a historical control group.

Results We included 129 adolescent after childbirth from January 1st, 2015 through July 31st, 2017. Out of this total, 63% had ever used contraceptive methods before pregnancy, and the most frequent method was combined oral contraceptives (33%) followed by condoms (21%). At the first postpartum consultation, the most common contraceptive chosen was intrauterine contraception (IUC) (37.2%) and depot-medroxyprogesterone acetate (DMPA) (34.1%). When comparing the rates before and after the education interventions, there was a 3-fold increase in the use of IUCs.

Conclusion Antenatal and postpartum education have shown a significant increase in the choice for LARC methods among adolescent mothers, with very high acceptability after a period using the method. The educational groups performed during the antenatal care and beyond the gestational period are easy to be applied worldwide with low dependence on funding.
Do We Know How to Avoid OASIs in Non-Supine Birth Positions? A Retrospective Cohort Analysis
Authors: Reis Zilma Silveira Nogueira , Pereira Glaucia Miranda Varella , Vianini Anna Laura Freitas , Monteiro Marilene Vale Castro , Aguiar Regina Amélia Lopes Pessoa
Published: October 2019

Objective To evaluate the association between the upright and supine maternal positions for birth and the incidence of obstetric anal sphincter injuries (OASIs).

Methods Retrospective cohort study analyzed the data of 1,728 pregnant women who vaginally delivered live single cephalic newborns with a birth weight of 2,500 g. Multiple regression analyses were used to investigate the effect of the supine and upright positions on the incidence of OASIs after adjusting for risk factors and obstetric interventions.

Results In total, 239 (13.8%) births occurred in upright positions, and 1,489 (86.2%) in supine positions. Grade-III lacerations occurred in 43 (2.5%) patients, and grade-IV lacerations occurred in 3 (0.2%) women. Supine positions had a significant protective effect against severe lacerations, odds ratio [95% confidence interval]: 0,47 [0.22–0.99], adjusted for the use of forceps 4.80 [2.15–10.70], nulliparity 2.86 [1.44–5.69], and birth weight 3.30 [1.56–7.00]. Anesthesia (p < 0.070), oxytocin augmentation (p < 0.228), shoulder dystocia (p < 0.670), and episiotomy (p < 0.559) were not associated with the incidence of severe lacerations.

Conclusion Upright birth positions were not associated with a lower rate of perineal tears. The interpretation of the findings regarding these positions raised doubts about perineal protection that are still unanswered.
Rare Case of Sarcomatoid Squamous Cell Carcinoma Arising in an Ovarian Mature Teratoma
Authors: Pedrosa Isabel Sofia de Sousa , Alpendre Filipa da Cunha Almeida , Sousa Rita , Dinis Sofia Raposo , Gomes Daniela
Published: October 2019

Although mature cystic teratoma (MCT) is benign, malignant transformation (MT) occurs in ∼ 1% to 2% of all cases, and usually consists of squamous cell carcinoma (SCC), which accounts for ∼ 80% of the cases. Spindle-cell (sarcomatoid) carcinoma (SCSC) is an uncommon type of SCC, comprising up to 3% of all cases. The lack of characteristic symptoms and specific imaging findings may lead to preoperative misdiagnosis. Moreover, the clinicopathologic characteristics, the treatment, the prognostic factors and the mechanism of MT have not yet been well understood due to the rarity of such tumors, especially in women of reproductive age. The authors present a case of a 34-year-old patient with 14 weeks of gestation who was diagnosed with an adnexal mass suggestive of ovarian teratoma. A laparoscopy salpingo-oophorectomy was performed after 6 months of delivery, and the histological exam revealed a sarcomatoid SCC in the MCT.
Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Retrosigmoid Approach
Authors: Graffeo Christopher S. , Peris-Celda Maria , Perry Avital , Carlstrom Lucas P. , Driscoll Colin L.W. , Link Michael J.
Published: October 2019

Introduction Neurosurgical anatomy is traditionally taught via anatomic and operative atlases; however, these resources present the skull base using views that emphasize three-dimensional (3D) relationships rather than operative perspectives, and are frequently written above a typical resident's understanding. Our objective is to describe, step-by-step, a retrosigmoid approach dissection, in a way that is educationally valuable for trainees at numerous levels.

Methods Six sides of three formalin-fixed latex-injected specimens were dissected under microscopic magnification. A retrosigmoid was performed by each of three neurosurgery residents, under supervision by the senior authors (C.L.W.D. and M.J.L.) and a graduated skull base fellow, neurosurgeon, and neuroanatomist (M.P.C.). Dissections were supplemented with representative case applications.

Results The retrosigmoid craniotomy (aka lateral suboccipital approach) affords excellent access to cranial nerve (CN) IV to XII, with corresponding applicability to numerous posterior fossa operations. Key steps include positioning and skin incision, scalp and muscle flaps, burr hole and parasigmoid trough, craniotomy flap elevation, initial durotomy and deep cistern access, completion durotomy, and final exposure.

Conclusion The retrosigmoid craniotomy is a workhorse skull base exposure, particularly for lesions located predominantly in the cerebellopontine angle. Operatively oriented neuroanatomy dissections provide trainees with a critical foundation for learning this fundamental skull base technique. We outline a comprehensive approach for neurosurgery residents to develop their familiarity with the retrosigmoid craniotomy in the cadaver laboratory in a way that simultaneously informs rapid learning in the operating room, and an understanding of its potential for wide clinical application to skull base diseases.
Far Lateral Approach for Clipping of a Posterior Inferior Cerebellar Artery Aneurysm
Authors: Basma Jaafar , Nguyen Vincent N. , Mangham William M. , Khan Nickalus R. , Sorenson Jeffrey , Michael L. Madison
Published: October 2019

Objectives To describe a far lateral approach for microsurgical clipping of a ruptured posterior inferior cerebellar artery (PICA) aneurysm involving the hypoglossal nerve, with emphasis on the microsurgical anatomy, and technique.

Design A far lateral craniotomy is performed in the lateral decubitus position and the transverse and sigmoid sinuses were exposed. After opening the dura, sutures are placed to allow gentle mobilization of the sinuses. The ipsilateral cerebellar tonsil is mobilized and the PICA is followed to its junction with the vertebral artery. Hypoglossal nerve rootlets are draped over the dome of the aneurysm. Mobilization of the PICA and the hypoglossal nerve away from the lateral medulla allows microsurgical clipping of the aneurysm neck. Photographs of the region are borrowed from Dr Rhoton's laboratory to illustrate the microsurgical anatomy.

Participants The senior authors performed the surgery. The video was edited by Drs. V.N. and J.B. Chart review and literature review were performed by Drs. W.M. and J.B.

Outcome Measures Outcome was assessed with successful clip occlusion and postoperative neurological function.

Results There was complete clip occlusion of the PICA aneurysm with no postoperative neurological deficits. The patient was discharged home after an uneventful hospital course.

Conclusion The far lateral approach provides an adequate corridor to the ventrolateral brainstem for microsurgical treatment of PICA aneurysms. An adequate understanding of the relevant microsurgical anatomy is the key to safe and effective clipping in this region.

The link to the video can be found at: https://youtu.be/yhjKRIG5H74.
Evaluation of the Mastoid Emissary Canals with Computerized Tomography in Patients with Chronic Otitis Media
Authors: Ozen Ozkan , Sahin Caner
Published: October 2019

Background The mastoid emissary veins (MEVs) pass through the mastoid emissary canal-mastoid foramen (MEC-MF) in the mastoid region of the skull. MEVs can give rise to complications during surgical procedures. The purpose of our study was to investigate the morphological and morphometric characteristics of MECs of patients with clinical chronic otitis media (COM) using high-resolution computed tomography (HRCT).

Methods Patients diagnosed with COM and undergoing temporal HRCT were identified by retrospectively scanning our hospital's automation system. Patients undergoing temporal HRCT for reasons other than COM, infection or tinnitus were identified for the control group by scanning the PACS archive. Sixty-two mastoid regions were examined in 38 unilateral and 12 bilateral COM patients, and 100 mastoid regions in the 50 patients in the control group. The presence of an accessory MEC-MF and MEC-MF diameters was evaluated in both groups.

Results Main MEC diameters on the side of the ear with COM were 1.6 mm, and total accessory and main MEC diameters were 1.8 mm, both values being significantly higher than in the control group. Presence of accessory MEC on the side of the ear with COM was determined at 61.8%, significantly higher than in the control group.

Conclusion Preoperative awareness of cranial venous drainage abnormalities is important to reduce surgical complications. Our study shows that MECs may be wider in diameter in patients with COM. MECs in COM patients must be identified before surgery to the mastoid region.
High bacterial inactivation on the aqueous brass surface for clinical trials by cold atmospheric plasma
Authors: Yu Yi
Published: October 2019

A cold atmospheric plasma (CAP) device has been developed to assess the bacterial inactivation on an aqueous brass surface for clinical trials. The Miles and Misra method and the decimal dilution method are used to count the number of colony forming units for mutual verification to certify the validity of this investigation. The experimental results show an exciting much higher bacterial inactivation on this CAP-brass system compared to the traditional sole CAP treatment; about 6–7 log reduction can be achieved in 30–60 s of application. This system can be used as a standard target to test the efficacy of plasma treatment in an aqueous condition, especially in hygiene, medicine, and food processing applications.
Electron trapping in the coma of a weakly outgassing comet
Authors: Sishtla Chaitanya Prasad , Divin Andrey , Deca Jan , Olshevsky Vyacheslav , Markidis Stefano
Published: October 2019

Measurements from the Rosetta mission have shown a multitude of nonthermal electron distributions in the cometary environment, challenging the previously assumed plasma interaction mechanisms near a cometary nucleus. In this paper, we discuss electron trapping near a weakly outgassing comet from a fully kinetic (particle-in-cell) perspective. Using the electromagnetic fields derived from the simulation, we characterize the trajectories of trapped electrons in the potential well surrounding the cometary nucleus and identify the distinguishing features in their respective velocity and pitch angle distributions. Our analysis allows us to define a clear boundary in velocity phase space between the distributions of trapped and passing electrons.
Twist-angle modulation of exciton absorption in MoS2/graphene heterojunctions
Authors: Zhang Xiangzhe , Yang Hang , Hou Weiwei , Zheng Xiaoming , Zhang Yi , Zhang Renyan , Deng Chuyun , Zhang Xueao , Qin Shiqiao
Published: October 2019

The twist-angle dependence of exciton absorption in a molybdenum disulfide (MoS2)/graphene heterostructure (MGH) is reported. Using photoluminescence (PL) spectroscopy, we found that, as the twist angle increased, the MGH demonstrated an enhancement of PL intensity and a peak position blueshift, indicating that the exciton radiative recombination was positively correlated with the twist angle. In addition, optical reflectance measurements were performed in order to investigate the exciton absorption in the MGH. It was found that the reflectance of MGH samples was twist-angle dependent at wavelengths of 620 and 670 nm, which corresponds to the PL peak positions of MoS2. This was attributed to the change in interlayer charge transfer for different twist angles. Our findings confirm the tunability of the electronic structure in MGHs via the interlayer twist, which enriches our understanding of interlayer coupling and is important for the future development of electronic and optoelectronic devices based on 2D material heterostructures.
Enhancement of ultrasonic transmission using a patch patterned with single-sided periodic gratings
Authors: Zhou Qinxin , Xu Wei , Xue Lei , Xu Zheng , Cheng Liming
Published: October 2019

We report that the transmission of incident ultrasonic waves through an impedance-mismatched brass plate can be drastically enhanced by single-sided periodic gratings. Using Schlieren imaging, we experimentally demonstrated the phenomenon of extraordinary acoustic transmission through the stiff, structured plate. Using a numerical model, we revealed that this phenomenon arises from the resonant excitation of the intrinsic A0 mode in this structure. We discussed the possible application of this structure as a patch to enhance ultrasound transmission in medical instruments.
Black phosphorus photodetector integrated with Au nanoparticles
Authors: Jeon Sumin , Jia Jingyuan , Ju Jae Hyeok , Lee Sungjoo
Published: October 2019

In this study, we propose a hybrid black phosphorus (BP)/Au nanoparticle (NP)-based photodetector, which greatly enhances the performance of photodetectors compared to BP-only photodetectors. By integrating Au NPs onto the BP surface, the light absorption was greatly enhanced owing to the localized surface plasmon resonance induced by the Au NPs, and the dark current of the photodetector was suppressed because the holes were withdrawn from the BP to the Au NPs due to the difference in the work function. After optimizing the density of the Au NPs, the responsivity of the BP/Au-NP photodetector reached 6000 and 500 A/W for 655 and 980 nm wavelengths, respectively, which are 60 and 500 times higher than those of BP photodetectors, respectively. The proposed hybrid photodetector, a two-dimensional (2D) semiconductor with noble metal NPs, opens up the possibility of realizing highly sensitive optoelectronic devices in the future.
Electrophoretic exclusion microscale sample preparation for cryo-EM structural determination of proteins
Authors: Zhu Fanyi , Nannenga Brent L. , Hayes Mark A.
Published: October 2019

Transmission electron microscopy (TEM) of biological samples has a long history and has provided many important insights into fundamental processes and diseases. While great strides have been made in EM data collection and data processing, sample preparation is still performed using decades-old techniques. Those sample preparation methods rely on extensive macroscale purification and concentration to achieve homogeneity suitable for high-resolution analyses. Noting that relatively few bioparticles are needed to generate high-quality protein structures, this work uses microfluidics that can accurately and precisely manipulate and deliver bioparticles to grids for imaging. The use of microfluidics enables isolation, purification, and concentration of specific target proteins at these small scales and does so in a relatively short period of time (minutes). These capabilities enable imaging of more dilute solutions and obtaining pure protein images from mixtures. In this system, spatially isolated, purified, and concentrated proteins are transferred directly onto electron microscopy grids for imaging. The processing enables imaging of more dilute solutions, as low as 5 × 10−6 g/ml, with small total amounts of protein (<400 pg, 900 amol). These levels may be achieved with mixtures and, as proof-of-principle, imaging of one protein from a mixture of two proteins is demonstrated.
Multifold nodal points in magnetic materials
Authors: Cano Jennifer , Bradlyn Barry , Vergniory M. G.
Published: October 2019

We describe the symmetry protected nodal points that can exist in magnetic space groups and show that only three-, six-, and eightfold degeneracies are possible (in addition to the two- and fourfold degeneracies that have already been studied). The three- and sixfold degeneracies are derived from “spin-1” Weyl fermions. The eightfold degeneracies come in different flavors. In particular, we distinguish between eightfold fermions that realize nonchiral “Rarita-Schwinger fermions” and those that can be described as four degenerate Weyl fermions. We list the (magnetic and nonmagnetic) space groups where these exotic fermions can be found. We further show that in several cases, a magnetic translation symmetry pins the Hamiltonian of the multifold fermion to an idealized exactly solvable point that is not achievable in nonmagnetic crystals without fine-tuning. Finally, we present known compounds that may host these fermions and methods for systematically finding more candidate materials.
Evidence for vacancy trapping in Au-hyperdoped Si following pulsed laser melting
Authors: Yang W. , Ferdous N. , Simpson P. J. , Gaudet J. M. , Hudspeth Q. , Chow P. K. , Warrender J. M. , Akey A. J. , Aziz M. J. , Ertekin E. , Williams J. S.
Published: October 2019

Nanosecond pulsed laser melting can be used to rapidly recrystallize ion-implanted Si through liquid phase epitaxy. The rapid resolidification that follows the melting results in a supersaturation of impurities and hyperdopes the Si, inducing novel optoelectronic properties with a wide range of applications. In this work, structural changes in the Si lattice in Au-hyperdoped Si are studied in detail. Specifically, we show that the local skewing of the lattice observed previously in regions of extremely high Au concentrations (>1.4 at. %) can be related to the displacement of Au from perfect lattice positions. Surprisingly, although the incorporation of the larger Au atoms into Si is expected to cause swelling of the lattice, reciprocal space mapping shows that a small amount (0.3 at. %) of lattice contraction (decrease in lattice parameter) is present in the hyperdoped layer. Furthermore, positron annihilation spectroscopy shows an elevated concentration of vacancies in the hyperdoped layer. Based on these observations and with the aid of density functional theory, we propose a phenomenological model in which vacancies are kinetically trapped into lattice sites around substitutional Au atoms during resolidification. This vacancy trapping process is hypothesized to occur as a means to minimize lattice strain and may be universal in pulsed laser melted Si systems.
Current-induced nucleation, manipulation, and reversible switching of antiskyrmioniums
Authors: Panigrahy Sujit Kumar , Singh Charanpreet , Nayak Ajaya K.
Published: October 2019

Magnetic skyrmioniums are unique spin structures that can be viewed as two skyrmions with an opposite skyrmion number providing a zero topological charge. Here, we propose a unique method to nucleate magnetic antiskyrmioniums in ferromagnetic materials with D2d symmetry. Using micromagnetic simulations, we show the stabilization of isolated antiskyrmionium from ferromagnetic as well as antiskyrmionic ground states. By invoking material specific parameters, we have established the regions of the stable antiskyrmionium phase and investigated their dynamics under current in-plane as well as perpendicular to plane geometry. Our study shows that antiskyrmioniums can be moved with a large velocity at very small current density in comparison to antiskyrmions and their anisotropic magnetization distribution provides a distinct current driven dynamics in comparison to skyrmioniums. Most importantly, we demonstrate that an antiskyrmionium can be stabilized and switched reversibly from a single antiskyrmion. We have also shown that the antiskyrmionium can be driven efficiently in an anisotropy gradient, where the velocity varies inversely with the damping constant. The present results add a distinct direction to the realization of antiskyrmionium based racetrack devices using D2d symmetry based materials.
The modification of exponents in the Ginzburg–Sobyanin theory of superfluidity
Authors: Poluektov Yu. M.
Published: October 2019

A suggested amendment to the temperature dependences in the thermodynamic potential of the Ginzburg–Sobyanin theory of superfluidity, which makes it possible to obtain critical exponents that are consistent with the general relations of the fluctuation theory of phase transitions, as well as with modern experimental and calculated data.
Spin-pair correlation driven the colossal magnetoresistance effect in multiferroics CdCr2S4
Authors: Xia Q. S. , Li J. , Wang C. N. , Wen J.
Published: October 2019

To understand the anomalous conductivity and colossal magnetoresistance effect of multiferroics CdCr2S4 around magnetic transition temperature TC, we propose the spin-pair correlation dependence of magnetic polarons model. In CdCr2S4, system shows the spontaneous magnetic order at TC and the magnetic order promotes the delocalization of magnetic polarons. According to the proposed model of a dual-conduction behavior, the normal and delocalized magnetic polarons coexist below TC due to the gradual delocalization process of magnetic polarons. Compared to the conductivity of normal magnetic polarons, the conductivity from the delocalized magnetic polarons is dominant. It is suggested that the spin-pair correlation modifies the hopping activation energy of delocalized polarons to realize the anomalous conductivity and colossal magnetoresistance effect. In addition, the applied magnetic field, which promotes the magnetic order and delocalization of magnetic polarons, also leads to the increase of conductivity via spin-pair correlation. It is found that the obtained conductivity and colossal magnetoresistance are in agreement with the experimental results.
Raman study of a magnetic phase transition in the MnPS3 single crystal
Authors: Peschanskii A. V. , Babuka T. Ya. , Glukhov K. E. , Makowska-Janusik M. , Gnatchenko S. L. , Vysochanskii Yu. M.
Published: October 2019

The Raman scattering spectra for the MnPS3 single crystal have been studied at frequencies ranging from 5 to 1200 cm−1, for temperatures ranging from 5 to 295 K. This is the first time that studies of low-temperature polarized Raman spectra in a magnetically ordered phase are presented for MnPS3. Energy splitting between some of Ag- and Bg-modes, which were previously believed to be energy equivalent in crystals from this family, has been found. The nature of the additional phonon lines observed in the Raman scattering spectra is discussed. It is found that at low temperatures, the magnetic scattering spectrum has a complex form that is related to the presence of both two-magnon and a phonon-magnon bands. The vibrational properties of the MnPS3 crystal were calculated using the LDA approximation with the DFT-D (OBS) dispersion correction implemented in the CASTEP computation package. Phonon dispersion curves and the total and partial phonon densities of states have been calculated in the antiferromagnetic phase of the MnPS3 crystal. The calculated results are in good agreement with the experimental Raman spectra.
Deformation-stimulated Ex luminescence in a RbI single crystal
Authors: Shunkeyev K. , Lushchik A. , Myasnikova L. , Sagimbaeva Sh. , Ubaev Zh. , Aimaganbetova Z.
Published: October 2019

Using X-ray luminescence spectra, the enhancement of both σ-luminescence of self-trapped excitons and Ех luminescence (band maxima at 3.89 and 3.1 eV, respectively) has been revealed for the first time in RbI single crystals exposed to elastic uniaxial stress at 93 K. The intensity of these emissions increases linearly with the relative degree of applied uniaxial deformation of the crystal up to ɛ = 1%, while the luminescence undergoes saturation at higher values of ɛ. The behavior of the I = f (ɛ) dependence for σ and Ех emissions suggests that Ех luminescence is intrinsic, and is connected with the radiative relaxation of self-trapped excitons in the field of local deformation of a RbI regular lattice.
Synthesis and optical properties of colloidal Cs2AgSb1−xBixCl6 double perovskite nanocrystals
Authors: Kshirsagar Anuraj S. , Nag Angshuman
Published: October 2019

Lead halide perovskites are extraordinary optoelectronic materials, but there are issues related to their toxicity and instability. To overcome these issues, various lead-free perovskites are being explored. Metal halide double perovskites, for example, Cs2AgSbCl6, in which two Pb2+ in CsPbCl3 (or Cs2Pb2Cl6) are replaced with one Ag+ and one Sb3+, provide both charge balanced and stable 3D perovskite structures. Synthesis of such double perovskites with different compositions, sizes, and solution processabilities still remains a challenge. The present communication describes synthesis and characterization of colloidal Cs2AgSb1−xBixCl6 alloy nanocrystals with 0 ≤ x ≤ 1. These nanocrystals exhibit an elpasolite structure where the lattice parameters vary systematically with the composition “x.” The nanocrystals are cubic in shape with an edge-length of ∼10 nm. UV-visible absorption spectra also change systematically with composition. The lowest energy absorption peak ∼3.4 eV becomes sharper along with a red-shift with increasing Bi content. The alloying can influence the optical absorption by both modifying the intrinsic electronic band structure and changing the concentration of antisite disorders. For intermediate compositions (x = 0.22, 0.36, and 0.70), photoluminescence with a peak at 2.74 eV is observed.
Distribution of rational points on the circle of unit radius
Authors: Korolev M. A. , Ustinov A. V.
Published: October 2019

We obtain an expression for the density of the distribution of the lengths of arcs connecting neighbouring rational points on the unit circle with denominators not exceeding a given bound.
Effects of temperature on tissue–diet isotopic spacing of nitrogen and carbon in otolith organic matter
Authors: Godiksen Jane A. , Chung Ming-Tsung , Folkvord Arild , Grønkjær Peter
Published: October 2019

Reconstruction of the trophic position of a fish can be performed by analysing stable nitrogen and carbon isotopes in otolith protein. However, ambient temperature may affect the tissue–diet isotopic spacing of stable isotopes from diet to predator tissue and bias estimates of trophic position. To test this, otolith protein, heart and muscle tissue from a rearing experiment with juvenile cod held at different temperatures (4, 7, 10 and 14°C) were analysed. There was no significant effect of temperature on otolith δ15N, whereas muscle and heart exhibited a slight decrease in δ15N values with increasing temperature corresponding to maximum of 0.6‰ over the 10°C range. By contrast, the otolith protein δ13C values at 4 and 7°C were significantly higher than for 10 and 14°C, suggesting an approximate 1‰ increased tissue–diet enrichment at the lower temperatures. Temperature had no significant effect on muscle and heart δ13C values. Considering the annual mean variation in ocean temperatures, our results indicate that the trophic signals recorded in the otoliths will reflect changes in diet isotope values with little bias from the ambient temperature experienced by the fish.
Collective cancer invasion forms an integrin-dependent radioresistant niche
Authors: Haeger Anna , Alexander Stephanie , Vullings Manon , Kaiser Fabian M.P. , Veelken Cornelia , Flucke Uta , Koehl Gudrun E. , Hirschberg Markus , Flentje Michael , Hoffman Robert M. , Geissler Edward K. , Kissler Stephan , Friedl Peter
Published: October 2019

Cancer fatalities result from metastatic dissemination and therapy resistance, both processes that depend on signals from the tumor microenvironment. To identify how invasion and resistance programs cooperate, we used intravital microscopy of orthotopic sarcoma and melanoma xenografts. We demonstrate that these tumors invade collectively and that, specifically, cells within the invasion zone acquire increased resistance to radiotherapy, rapidly normalize DNA damage, and preferentially survive. Using a candidate-based approach to identify effectors of invasion-associated resistance, we targeted β1 and αVβ3/β5 integrins, essential extracellular matrix receptors in mesenchymal tumors, which mediate cancer progression and resistance. Combining radiotherapy with β1 or αV integrin monotargeting in invading tumors led to relapse and metastasis in 40–60% of the cohort, in line with recently failed clinical trials individually targeting integrins. However, when combined, anti-β1/αV integrin dual targeting achieved relapse-free radiosensitization and prevented metastatic escape. Collectively, invading cancer cells thus withstand radiotherapy and DNA damage by β1/αVβ3/β5 integrin cross-talk, but efficient radiosensitization can be achieved by multiple integrin targeting.
Disruption of mosGILT in Anopheles gambiae impairs ovarian development and Plasmodium infection
Authors: Yang Jing , Schleicher Tyler R. , Dong Yuemei , Park Hyun Bong , Lan Jiangfeng , Cresswell Peter , Crawford Jason , Dimopoulos George , Fikrig Erol
Published: October 2019

Plasmodium infection in Anopheles is influenced by mosquito-derived factors. We previously showed that a protein in saliva from infected Anopheles, mosquito gamma-interferon–inducible lysosomal thiol reductase (mosGILT), inhibits the ability of sporozoites to traverse cells and readily establish infection of the vertebrate host. To determine whether mosGILT influences Plasmodium within the mosquito, we generated Anopheles gambiae mosquitoes carrying mosaic mutations in the mosGILT gene using CRISPR/CRISPR associated protein 9 (Cas9). Here, we show that female mosaic mosGILT mutant mosquitoes display defects in ovarian development and refractoriness to Plasmodium. Following infection by either Plasmodium berghei or Plasmodium falciparum, mutant mosquitoes have significantly reduced oocyst numbers as a result of increased thioester-containing protein 1 (TEP1)–dependent parasite killing. Expression of vitellogenin (Vg), the major yolk protein that can reduce the parasite-killing efficiency of TEP1, is severely impaired in mutant mosquitoes. MosGILT is a mosquito factor that is essential for ovarian development and indirectly protects both human and rodent Plasmodium species from mosquito immunity.