bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of coupling assessments on conceptual understanding and connection-making in chemical equilibrium and acid–base chemistry
Authors: Ye Li , Eichler Jack F. , Gilewski Alex , Talbert Lance E. , Mallory Emily , Litvak Mikhail , M. Rigsby Emily , Henbest Grace , Mortezaei Kiana , Guregyan Cybill
Published: May 2020

Science educators have developed a variety of assessment techniques to help students connect their scientific knowledge and bridge conceptual gaps. In chemistry, concept maps and creative exercises are the two notable assessments that have been implemented into multiple chemistry courses and indicated promising effects on students’ conceptual learning and connection-making between chemistry concepts. These two assessment techniques were usually implemented individually in research studies. Herein, we employed a quasi-experimental, mixed-methods approach to explore whether combining concept maps and creative exercises would reveal any synergistic effects for student learning of chemical equilibrium and acid–base chemistry in a college general chemistry course. In this study, student perceptions of the use of the two assessments were examined by open-ended surveys. Interestingly, students perceived creative exercises as an assessment technique while concept maps were viewed as a learning tool for studying or reviewing exams. Additionally, Students believed that concept maps assisted them in answering creative exercises, but not vice versa. The four study groups (control group, concept maps only, creative exercises only, and both concept maps and creative exercises) were compared through concept inventory pre and post-test questions. The results of an ANCOVA indicated that participation in the experimental groups did not significantly impact conceptual learning gains, as measured by the concept inventory post-test scores. However, focus group interviews indicated students from the experimental group that used both concept maps and creative exercises were able to provide more sophisticated scientific explanations for conceptual questions related to the topics of chemical equilibrium and acid–base chemistry. Implications of these research results, best practices for implementation of the two assessments, and future research are discussed.
Recent advances in Co-based electrocatalysts for the oxygen reduction reaction
Authors: Liang Zuozhong , Zheng Haoquan , Cao Rui
Published: May 2020

A summary of recent advances in Co-based electrocatalysts for the oxygen reduction reaction in fuel cells.
Passivation of defects in inverted perovskite solar cells using an imidazolium-based ionic liquid
Authors: Luo Chuanyao , Li Guannan , Chen Lijia , Dong Jun , Yu Miao , Xu Cunyun , Yao Yanqing , Wang Meng , Song Qunliang , Zhang Sam
Published: May 2020

This work provides an easy approach to achieve high-performance perovskite solar cells via passivation of the uncoordinated Pb2+ in perovskite films by the cationic group of ionic liquids.
Adsorption behaviors of branched cationic gemini surfactants and wettability in quartz–solution–air systems
Authors: Gao Ming , Wang Xiao-Guang , Lv Wei-Feng , Zhou Zhao-Hui , Zhang Qun , Ma De-Sheng , Wang Hong-Zhuang , Yan Feng , Zhang Lei , Zhang Lu
Published: May 2020

We investigate the adsorption and wetting on quartz surfaces by aqueous solutions of xylyl-substituted biquaternary ammonium salt gemini surfactants with different spacer groups (C3 and C6).
Enhancing CO2 reduction by suppressing hydrogen evolution with polytetrafluoroethylene protected copper nanoneedles
Authors: An Pengda , Wei Lai , Li Huangjingwei , Yang Baopeng , Liu Kang , Fu Junwei , Li Hongmei , Liu Hui , Hu Junhua , Lu Ying-Rui , Pan Hao , Chan Ting-Shan , Zhang Ning , Liu Min
Published: May 2020

Enhanced carbon dioxide reduction reaction (CO2RR) with suppressed HER was achieved on polytetrafluoroethylene (PTFE) coated Cu nanoneedles (CuNNs).
Synergy in the energy transfer between ligands and EuIII ions in molecular europium complexes: single-component white light-emitting luminogens
Authors: Devi Rachna , Singh Kasturi , Vaidyanathan Sivakumar
Published: May 2020

Due to their structural flexibility and easy solution process capability, single-component white light-emitting pure organo-lanthanide complexes have been considered as promising candidates for solid-state lighting.
Dysregulation of miR-192-5p in acute pancreatitis patients with nonalcoholic fatty liver and its functional role in acute pancreatitis progression
Authors: Hu Yang , Yu Yongming
Published: May 2020

Background: Nonalcoholic fatty liver disease (NAFLD) is a frequent metabolic disease and has been demonstrated to contribute to the severity of acute pancreatitis (AP). The present study aimed to investigate the aberrant expression of microRNA-192-5p (miR-192-5p) in AP patients with NAFLD, and further analyze the clinical significance and biological function of miR-192-5p in AP progression.

Methods: Expression of miR-192-5p was estimated using quantitative real-time PCR (qRT-PCR). Diagnostic value of miR-192-5p was evaluated by the receiver operating characteristic curve (ROC). The effects of miR-192-5p on cell proliferation, apoptosis and inflammatory response of pancreatic acinar cells were further assessed by CCK-8 assay, flow cytometry and enzyme-linked immunosorbent assay (ELISA).

Results: Circulating miR-192-5p was decreased in AP patients with NAFLD compared with those patients without NAFLD and healthy controls (P<0.05). The down-regulated expression of miR-192-5p had a relative high diagnostic accuracy to distinguish the AP patients with NAFLD from the cases without NAFLD. Furthermore, the overexpression of miR-192-5p in pancreatic acinar cells led to the decreased cell proliferation, increased cell apoptosis and suppressed inflammatory reaction (all P<0.05).

Conclusion: Collectively, all data indicated that serum expression of miR-192-5p in AP patients with NAFLD is significantly decreased and serves as a candidate diagnostic biomarker. The up-regulation of miR-192-5p in pancreatic acinar cell leads to increased cell apoptosis and decreased inflammatory response, suggesting the potential of miR-192-5p as a therapeutic target of AP.
TP53 Arg72Pro polymorphism and neuroblastoma susceptibility in eastern Chinese children: a three-center case–control study
Authors: Fang Yuan , Wu Xuemei , Li Lin , Zhu Jinhong , Wu Haiyan , Zhou Haixia , He Jing , Wang Yizhen
Published: May 2020

TP53 is a tumor suppressor gene that regulates cell growth, apoptosis and DNA repair. Previous studies have reported the contribution of TP53 Arg72Pro (rs1042522 C>G) polymorphism to pathogenesis of multiple tumors. Hence, we evaluated the association between this polymorphism and neuroblastoma susceptibility in eastern Chinese children. The Taqman genotyping assay was performed in 373 patients and 762 controls. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the strength of the association. No significant association was found between the TP53 gene rs1042522 C>G polymorphism and neuroblastoma susceptibility in the overall analysis (CG vs. CC: adjusted OR = 0.92, 95% CI = 0.70–1.22, P=0.567; GG vs. CC: adjusted OR = 0.99, 95% CI = 0.69–1.42, P=0.947; CG/GG vs. CC: adjusted OR = 0.94, 95% CI = 0.72–1.23, P=0.639; or GG vs. CC/CG: adjusted OR = 1.04, 95% CI = 0.75–1.43, P=0.814) and stratified analysis by age, gender, sites of origin, and clinical stages. The TP53 gene rs1042522 C>G polymorphism may not be a risk factor for neuroblastoma in eastern Chinese children. Future studies are needed to confirm this negative result and to reveal additional functional TP53 variants predisposing to neuroblastoma.
A pilot study on investigating the role of Salvia miltiorrhiza in fetal growth restriction
Authors: Shen Fanghua , Lv Hongdao , Shi Yun , Lau Sandy , Guo Fang , Chen Qi
Published: May 2020

To date there is no effective treatment for pregnancies complicated by fetal growth restriction (FGR). Salvia miltiorrhiza, a traditional Chinese herb has been shown to promote blood flow and improve microcirculatory disturbance. In this pilot study, we evaluated whether S. miltiorrhiza can potentially become a possible therapy for FGR. Nineteen pregnant women with FGR were treated with S. miltiorrhiza and ATP supplementation for an average of 7 days, and 17 cases received ATP supplementation as controls. The estimated fetal weights (EFWs) were measured by ultrasound after treatment, and the birthweights were recorded after birth. After treatment with S. miltiorrhiza, 7 (37%) FGR cases showed an increase in EFW to above the 10th percentile, compared with 4 (23%) FGR cases in controls (odds ratio: 1.896, 95% confidence limits (CLs): 0.44–8.144). At delivery, 10 (53%) FGR cases in the treatment group delivered babies with a birthweight above the 10th percentile, compared with 6 (35%) FGR cases in the control group (odds ratio: 2.037, 95% CL: 0.532–7.793); 80 or 64% FGR cases in the treatment group showed an increase in fetal abdominal circumference (AC) or biparietal diameter (BPD) above the 10th percentile before delivery. While 44 or 30% FGR cases in the control group showed an increase in AC or BPD. No improvement of head circumference (HC) or femur length (FL) was seen. These pilot data suggest the need for multicenter randomized clinical trials on the potential of S. miltiorrhiza to improve perinatal outcome in pregnant women complicated by FGR.
Characteristics of the Frequency-Following Response to Speech in Neonates and Potential Applicability in Clinical Practice: A Systematic Review
Authors: Richard Céline , Neel Mary Lauren , Jeanvoine Arnaud , Connell Sharon Mc , Gehred Alison , Maitre Nathalie L.
Published: May 2020

Purpose

We sought to critically analyze and evaluate published evidence regarding feasibility and clinical potential for predicting neurodevelopmental outcomes of the frequency-following responses (FFRs) to speech recordings in neonates (birth to 28 days).

Method

A systematic search of MeSH terms in the Cumulative Index to Nursing and Allied HealthLiterature, Embase, Google Scholar, Ovid Medline (R) and E-Pub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily, Web of Science, SCOPUS, COCHRANE Library, and ClinicalTrials.gov was performed. Manual review of all items identified in the search was performed by two independent reviewers. Articles were evaluated based on the level of methodological quality and evidence according to the RTI item bank.

Results

Seven articles met inclusion criteria. None of the included studies reported neurodevelopmental outcomes past 3 months of age. Quality of the evidence ranged from moderate to high. Protocol variations were frequent.

Conclusions

Based on this systematic review, the FFR to speech can capture both temporal and spectral acoustic features in neonates. It can accurately be recorded in a fast and easy manner at the infant's bedside. However, at this time, further studies are needed to identify and validate which FFR features could be incorporated as an addition to standard evaluation of infant sound processing evaluation in subcortico-cortical networks. This review identifies the need for further research focused on identifying specific features of the neonatal FFRs, those with predictive value for early childhood outcomes to help guide targeted early speech and hearing interventions.
Digital LDO regulator with analogue‐assisted loop using source follower
Authors: Kim E. , Kim C.
Published: May 2020

A digital low‐dropout regulator (DLDO) with an analogue‐assist (AA) loop using a source follower has been proposed to improve the drawbacks of the DLDO. The proposed AA loop, which uses a source follower structure to generate the compensation current without additional passive components, mitigates the voltage droop and accelerates the transient response by complementing a slow digital control loop. Additionally, the boost loop enhances the deceleration of the compensation speed owing to the size of the power transistors. This ultimately results in the improvement of the transient response to the voltage droop side. Also, this can facilitate in reducing the amount of the output capacitance (COUT) closely associated with the output voltage droop (ΔVOUT). The proposed DLDO occupying an area of 0.015 mm2 is designed in a 28‐nm CMOS process. The ΔTs of 14 ns with COUT of 10 pF is achieved under the load step of 1.5–30 mA with edge time of 2 ns. The consumed quiescent current is 35 μA, and the figure‐of‐merit of 0.008 ps is achieved.
Influence of hybrid laminated remanufactured stator core on no‐load air‐gap magnetic density
Authors: Song Shouxu , Du Yi , Hu Mengcheng
Published: May 2020

Considering the cost and performance of the remanufactured motor, a motor remanufacturing method with a hybrid stator core structure was proposed, a prototype of the remanufacturing motor was made and the experiment was carried out. The modified magnetic circuit model of the hybrid stator motor was established by fitting the B–H curves of the two materials to consider the influence of the stator material. The errors for silicon steel and amorphous alloy were approximately 4.9 and 4.3%, respectively. The variation in no‐load air‐gap magnetic density along the axial direction was studied via simulation, and the air‐gap flux density decreases gradually from the centre of silicon steel segment to the centre of amorphous alloy segment. A deflection occurs in the distribution of the air‐gap magnetic field, which is in connection with the saturation degree of the materials. The method for calculating the air‐gap magnetic density of the hybrid laminated stator from the magnetic density of the two materials was proposed. Compared with the stator composed of only one material, the calculation result obtained by the proposed method is in good agreement with the simulation result, with an error of <5%.
Conducted common‐mode electromagnetic interference suppression in the AC and DC sides of a grid‐connected inverter
Authors: Liu Yitao , Mei Zhaozhao , Jiang Shiqi , Liang Weihua
Published: May 2020

Electromagnetic interference (EMI) filters are inevitable parts of power electronic systems. A novel EMI filter for single‐phase grid‐inverter is proposed in this study, to suppress the common‐mode (CM) EMI noise. The noise source and propagation path impedances are analysed, and the interaction between AC and DC side is studied. By connecting the ground terminal of the CM capacitors to the midpoint of the DC‐link, the noise coupling between AC and DC side is reduced. When compared with the state‐of‐the‐art of EMI filter, the proposed topology has advantages: the AC and DC filters can be designed independently; the impedance of the CM loop is improved; there is a remarkable CM EMI noise suppression effect on both AC and DC sides. Simulation and experimental results verify the theoretical analysis and proposed EMI filter structure.
Improved post‐fault operation strategy for a cascaded H‐bridge based STATCOM
Authors: Neyshabouri Yousef , Iman‐Eini Hossein , Chaudhary Sanjay K. , Jin Yu , Teodorescu Remus
Published: May 2020

This study presents a multi‐fault tolerant strategy for a cascaded H‐bridge (CHB) based static synchronous compensator (STATCOM) with star configuration. A new method for post‐fault operation of CHB‐STATCOM is proposed, where after switch failures, the full‐bridge (FB) submodules are used as two different types of half‐bridge submodules named as positive half‐bridge (P‐HB) and negative half‐bridge (N‐HB). Using a modified level shift pulse‐width modulation technique, a combination of FB, P‐HB and N‐HB submodules is employed in three legs of the converter to generate the maximum attainable ac side voltage in post‐fault condition. In order to restore the nominal capacity of CHB‐STATCOM, the capacitor voltage of submodules is increased based on the type and number of switch failures. Furthermore, by utilising a voltage balancing strategy, the voltages of submodules’ capacitors are kept balanced and regulated at the desired value in post‐fault condition. The feasibility and effectiveness of the proposed strategy is validated on a scaled‐down 9‐level CHB‐STATCOM laboratory prototype.
Generalised analysis of the high‐voltage‐gain interleaved ZVS boost‐flyback converter
Authors: Gonçalves Pedro José Faure , Agostini Eloi
Published: May 2020

This study proposes the generalised analysis of the interleaved zero‐voltage‐switching (ZVS) boost‐flyback converter containing a number k of interleaving cells. The analysis provides a general description of the energy transfer process of the circuit and yields a systematic approach for the adequate converter design. The effect of the leakage inductance on the voltage gain is verified in detail, enabling the designer to deal with the trade‐off between high step‐up operation and soft‐switching occurrence. In addition, the conditions to guarantee ZVS for all switches are investigated, providing the basis for the adequate choice of the auxiliary switching capacitance and dead time. Experimental results obtained from the testing of a 500 W, 100 kHz, 96.9% peak efficiency prototype validate the analysis carried out and the proposed design procedure for the converter.
Analysis and design of defected ground structure for EMC improvement in mixed‐signal transceiver modules
Authors: Heidari Salomeh , Masoumi Nasser , Rashed Mohassel Jalil , Karimian Noushin , Safavi‐Naeini Safieddin
Published: May 2020

In this research, the return path discontinuity (RPD), located under the power amplifier (PA) substrate, of X‐band transceiver module (Base), mounted on a four‐layer printed circuit board (PCB), is investigated to improve the signal integrity by reducing the difference in the reference potential. This study is performed by initially employing the wirebond method, through the assessment of both numbers and sizes of bondwires by advanced design system (ADS). Six bondwires of 25 µm are added, producing an improvement of 6.82 dB for the reflection coefficient and 1.19 dB for the isolation and insertion loss. For further improvement, spiral shape defected ground structure (DGS) is implemented in the inner ground layer (layer 2) without using bond wires. The DGS simulation results illustrate an improvement of 3 dB for S11 and 0.6 dB for S12. To improve the electromagnetic compatibility (EMC), the authors propose combination and integration of both wirebond and DGS methods, called wirebond–DGS method, which results in an improvement of 11.86 dB for S11, 1.34 dB for S12 and S21, and 12.03 dB for S22. Finally, the wirebond–DGS RF module was fabricated and the measurement results exhibit an improvement of 8.07 dB for S11 and 9.39 dB for S22 in comparison with the fabricated Base module. In addition, 0.53 dB improvement for both S12 and S21 is also achieved.
Das Komplementsystem: von den Grundlagen zur klinischen Bedeutung
Authors: Schröder-Braunstein Jutta , Kirschfink Michael
Published: May 2020

Als Teil der unspezifischen Abwehr ist das Komplementsystem jederzeit verfügbar und somit bereits in der Frühphase von Infektionen von unschätzbarem Wert, bevor nach Bereitstellung spezifischer Antikörper und T-Zellen das adaptive Immunsystem zielgerichtet seine volle Wirkung entfaltet. Aufgrund seiner Rolle in der Pathophysiologie verschiedener Krankheitsbilder besitzt das Komplement eine besondere Bedeutung für die Klinik. Sowohl für die Aufklärung von Komplementdefekten und -fehlregulationen als auch zur Früherkennung lebensbedrohlicher Prozesse, wie z. B. der Entwicklung eines Multiorganversagens nach schwerem Trauma, Verbrennungen oder Sepsis sowie zur Einschätzung der Wirksamkeit neuer Therapieansätze, ist eine moderne Komplementdiagnostik heutzutage unabdingbar. Mit diesem Übersichtsartikel wollen wir einen Bogen spannen von den Grundlagen des Komplementsystems über dessen klinische Relevanz und diagnostische Maßnahmen bis hin zu aktuellen Möglichkeiten einer zielgerichteten Therapie.
Lebensmittel-bezogene Verhältnisprävention von Adipositas und nichtübertragbaren Krankheiten – der politische Prozess in Deutschland
Authors: Gerlach Stefanie
Published: May 2020

Ziel Der Artikel beschreibt den politischen Prozess der Etablierung der Nationalen Reduktions- und Innovationsstrategie für Zucker, Fette und Salz in Fertigprodukten und eines verbesserten Nährwertkennzeichnungssystems in Deutschland, mit Fokus auf dem Beitrag und der Rolle von Wissenschafts- und Gesundheitsorganisationen.

Methodik Narrativ.

Ergebnisse Vom Bundesministerium für Landwirtschaft und Ernährung (BMEL) eingeladen, als Berater den Prozess der Etablierung der nationalen Reduktions- und Innovationsstrategie für Zucker, Fette und Salz in Fertigprodukten sowie einer verbesserten Nährwertkennzeichnung zu begleiten, konnten Wissenschafts- und Gesundheitsorganisationen den politisch vorgegebenen, freiwilligen Ansatz nicht verhindern. Ihre konzertierte und öffentlichkeitswirksame Kommunikation beeinflusste die öffentliche Meinung jedoch stark und unterstützte den Durchbruch des Nutri-Score in Deutschland.

Schlussfolgerungen Wollen Wissenschafts- und Gesundheitsorganisationen evidenzbasierte Strategien politisch umgesetzt sehen, reichen Forschung und Sachkenntnis nicht aus. Es bedarf des Aufbaus einer gesellschaftlichen Dynamik mittels einer nachhaltigen und strategischen „Lobby pro Gesundheit“, um über die Modifikation des öffentlichen Diskurses die Politik zu beeinflussen.
Hinter den Kulissen – Als Physiotherapeut in der Wissenschaft
Authors: Laquai Sophia
Published: May 2020

Forschen klingt für viele interessant, aber auch wenig greifbar. Die Therapeuten der Forschungsabteilung der Klinik für Geriatrische Rehabilitation am Robert-Bosch-Krankenhaus geben Einblick in ihren Arbeitsalltag. Dabei wird schnell klar, dass Wissenschaft ganz und gar nicht trocken sein muss, sondern ziemlich abwechslungsreich und praxisnah sein kann.
Auf die Mischung kommt es an – Bewerber filtern
Authors: Freitag-Herse Barbara
Published: May 2020

Bei der Besetzung einer Stelle achten Arbeitgeber auf einiges: vollständige Unterlagen, einen gelungenen Probetag und Berufserfahrung. Und sympathisch soll der neue Mitarbeiter sein – oder ist das gar nicht so wichtig? Bei der Wahl eines neuen Arbeitnehmers sollten Sie nicht nur auf Ihr Bauchgefühl hören.
Aus der Frühzeit der Ästhetischen Chirurgie: Eugen Holländer (1867–1932) und Erich Lexer (1867–1937) als Face-Lift-Pioniere
Authors: Locher Wolfgang G. , Feinendegen Dominik L.
Published: May 2020

Einleitung und Hintergrund Der Wunsch der Menschen nach besserem Aussehen zieht sich durch die gesamte Geschichte und erreichte Anfang des 20. Jahrhunderts auch die Plastische Chirurgie. Insbesondere ging es dabei um die Facelift-Chirurgie und die beiden deutschen Pioniere in diesem Feld: Eugen Holländer und Erich Lexer.

Ziel der Arbeit Bei der Entwicklung der Facelift-Techniken wirkten die beiden Chirurgen Eugen Holländer und Erich Lexer entscheidend mit. Die Arbeit untersucht wie sich diese beiden Chirurgen mit dem Thema beschäftigten und welche Erkenntnisse sich daraus für die weitere Entwicklung der Facelift-Chirurgie ergaben.

Methodik Anhand der alten Fachliteratur und Kongresszitaten werden die Lebensläufe von Eugen Holländer sowie Erich Lexer dargestellt, sowie ihre beruflichen Karrieren und ihre für die Facelift-Chirurgie entscheidenden Pionierarbeiten und Unterschiede dargestellt.

Schlussfolgerung Sowohl Eugen Holländer als auch Erich Lexer führten unabhängig voneinander die ersten Facelifts in Deutschland durch (Eugen Holländer 1901). Dabei unterschieden Sie sich klar durch das operative Vorgehen. Im Gegensatz zu Holländer, der lediglich Hautresektionen zur verbesserten Gesichtsspannung durchführte, unterminierte Lexer die Haut auf mehrere Zentimeter. Auch bei der Naht-Technik unterschieden sich beide klar voneinander. So führte Lexer bereits tiefgreifende die Fascia temporalis superficialis miteinbeziehende Nähte zur langfristigen Spannungsentlastung durch. Lexer gilt somit zurecht als der eigentliche Pionier der modernen Faceliftchirurgie.
An Efficient Two-Step Protocol for the Isoprenylation of Xanthone at the C2 Position Starting from 1-Fluoroxanthone Derivative
Authors: Matsumoto Takashi , Fujimoto Yuuki , Furukawa Chisato , Takahashi Kanae , Mochizuki Miho , Yanai Hikaru
Published: May 2020

The SNAr reaction of 1-fluoroxanthone derivatives with alkoxide of 1,1-dimethylallyl alcohol cleanly afforded the corresponding ethers, which have thus far been unavailable. The obtained ethers underwent the Claisen rearrangement at room temperature by treatment with silica gel in toluene. This two-step protocol provides expeditious and high-yield access to xanthones possessing isoprenyl or the related allylic side chain at the C2 position.
Morphometric Study of Uncinate Process of Cervical Vertebra and Its Surgical Importance
Authors: P. Durga , R. Dakshayani K.
Published: May 2020

Introduction Uncinate process is a projection on the posterolateral margins of the superior surface of the body of cervical vertebra. They are involved in uncovertabral (Luschka’s) joints, with intervertebral foramen in between, which is related to the vertebral artery and spinal nerve roots. Osteophytes of uncinate process cause narrowing of intervertebral foramen, resulting in cervical spondylotic radiopathy.

Objectives To measure the morphometric parameters of the uncinate process of cervical vertebra. To classify cervical vertebra on the basis of the encroachment of uncinate process on the adjacent intervertebral foramen.

Materials and Methods 100 dry cervical vertebrae were obtained from regions in and around Mysore, Karnataka, India. Measurements were taken using digital Vernier callipers.

Results Mean average values of the parameters are: width–3.389 ± 0.83 mm (right), 3.389 ± 0.86 mm (left); length–10.42 ± 1.46 mm (right), 10.64 ± 1.88 mm (left); height- 5.32 ± 1.36 mm (right), 5.21 ± 1.16 mm (left). Classification of uncinate process: Type 1 (no encroachment)–82%; Type 2 (inclined and encroached)–12%; Type 3 (not inclined, but large enough to encroach)–6%

Conclusion Comparing the results of the present study with previous studies in different regions will help the neurosurgeons in determining the boundaries of uncinate process and allow adequate decompression of neural elements, with reduced risk of neurovascular structures during anterior decompression of spine.
Recent Advances in Triarylmethane Synthesis
Authors: Zhang Ling , Lin Xiaoyan , Huang Dayun , Liu Xue , Wu Xiangmei
Published: May 2020

Triarylmethanes are important molecules in organic chemistry. This review discusses advances in their synthesis summarized in five categories according to the starting materials: (1) benzyl reagents with different leaving groups, such as benzyl alcohols, ethers, esters, phosphates, sulfones, thioethers, sulfonamide, 1,3-dicarbonyls, and ammonium salts; (2) reactions via para- or ortho-quinone methides; (3) arylation of benzyl halides; (4) C–H activation of methylenes; and (5) reactions of aldehydes or N-tosylhydrazones. Triarylmethane derivatives such as 9-arylxanthenones, 9-arylfluorenes, and aryloxepines are also discussed.

1 Introduction

2 Benzyl Reagents with Leaving Groups

3 Quinone Methide Mediated Reactions

4 Arylation of Benzyl Halides

5 C–H Activation of Methylene

6 Reactions of Carbonyl Compounds

7 Conclusions
Transition-Metal-Catalyzed Amination of Aryl Fluorides
Authors: Shi Hang , Kang Qi-Kai , Lin Yunzhi , Li Yuntong
Published: May 2020

Arene activation via transition-metal (TM) η6-coordination has merged as a powerful method to diversify the aromatic C–F bond, which is relatively less reactive due to its high bond energy. However, this strategy in general requires to use largely excess arenes or TM η6-complexes as the substrates. Herein, we highlight our recent work on the catalytic SNAr amination of electron-rich and electron-neutral aryl fluorides that are inert in classical SNAr reactions. This protocol enabled by a Ru/hemilabile ligand catalyst covers a broad scope of substrates without wasting arenes. Mechanistic studies revealed that the nucleo­philic substitution proceeded on a Ru η6-arene complex, and the hemilabile ligand significant promoted the arene dissociation.
Carotid Revascularization: Current Practice and Future Directions
Authors: Bagley Jacob H. , Priest Ryan
Published: May 2020

Carotid stenosis is responsible for approximately 15% of ischemic strokes. Carotid revascularization significantly decreases patients' stroke risk. Carotid endarterectomy has first-line therapy for moderate-to-severe carotid stenosis after a series of pivotal randomized controlled trials were published almost 30 years ago. Revascularization with carotid stenting has become a popular and effective alternative in a select subpopulation of patients. We review the current state of the literature regarding revascularization indications, patient selection, advantages of each revascularization approach, timing of intervention, and emerging interventional techniques, such as transcarotid artery revascularization.
Dangerous Extracranial–Intracranial Anastomoses: What the Interventionalist Must Know
Authors: Rinaldo Lorenzo , Brinjikji Waleed
Published: May 2020

The extracranial and intracranial circulations are richly interconnected at numerous locations, a functional connectivity which underlies their impressive capacity for adaptive plasticity in the setting of vasoocclusive disease. While evolutionarily beneficial, these connections can also result in inadvertent communication with the intracranial circulation during embolization of extracranial vessels, potentially resulting in stroke or cranial nerve palsy. While these anastomoses are always present to a certain extent, flow through them occurs under predictable circumstances, and thus embolization of the extracranial vasculature can be performed safely when knowledge of functional anatomy is combined with adherence to basic principles. Herein, we will review the anatomy of known extracranial–intracranial anastomoses and strategies for avoidance of unwanted intracranial embolization. We will also review the vascular supply to cranial nerves most at risk during common neurointerventional procedures, as well as blood supply to mucosal structures.
Interventional Management of Head and Neck Tumors
Authors: Kamran Mudassar , Wallace Adam N. , Adewumi Amole
Published: May 2020

Advancements in medical imaging and device technology allow minimal invasive procedures for the diagnosis and treatment of various disorders. For the management of tumors in head and neck region, these image-guided interventions play essential role in the often used multidisciplinary approach. Tissue sampling under ultrasound or computed tomography guidance is generally the first step to reach a pathological diagnosis. For head and neck tumors with high vascularity, embolization using particulate matter, liquid embolic agents, or coils is used to achieve successful tumor resection with minimal blood loss. Hemorrhage related to head and neck tumors can be evaluated and managed with endovascular techniques with minimal morbidity and mortality. Intra-arterial chemotherapy, radiofrequency ablation, and cryotherapy are new techniques for the management of advanced head and neck cancer which may serve as an alternative to achieve locoregional control and survival when curative resection may not be feasible.
Percutaneous Interventional Techniques for Treatment of Spinal Metastases
Authors: Tomasian Anderanik , Jennings Jack W.
Published: May 2020

This article details an approach for evaluation as well as minimally invasive percutaneous treatment of spinal metastases focusing on thermal ablation and most recent advances. Safe and effective management of certain subgroups of patients with spinal metastases can be achieved by minimally invasive percutaneous thermal ablation with or without vertebral augmentation. Adjunctive palliative treatment options such as epidural or neuroforaminal corticosteroid and long-acting anesthetic injections may also be performed in patients who have nerve and radicular pain including those who are not candidates for thermal ablation. Thermal protection strategies should be implemented to minimize the risk of neural thermal injury.
Endovascular Stroke Interventions: Procedural Complications and Management
Authors: Elakkad Ahmed , Drocton Gerald , Hui Ferdinand
Published: May 2020

Endovascular mechanical thrombectomy has evolved significantly and has become the mainstay and most effective currently available treatment for acute ischemic stroke patients due to large vessel occlusion. Mechanical thrombectomy is presently performed using a stent retriever or stent-like device, an aspiration catheter, or a combination of the two. Much of the literature has focused on the benefits of endovascular mechanical thrombectomy with only limited data about procedural complications and management. Awareness of risk factors and early recognition of these complications can potentially reduce complication rates, improve management, and yield better overall outcomes. In this review, the authors present a description of intraprocedural complications and strategies to prevent and treat these complications.
The Role of Lower Extremity Amputation in Chronic Limb-Threatening Ischemia
Authors: Kim Tanner I. , Mena Carlos , Sumpio Bauer E.
Published: May 2020

Chronic limb-threatening ischemia (CLTI) is a severe form of peripheral artery disease associated with high rates of limb loss. The primary goal of treatment in CLTI is limb salvage via revascularization. Multidisciplinary teams provide improved care for those with CLTI and lead to improved limb salvage rates. Not all patients are candidates for revascularization, and a subset will require major amputation. This article highlights the role of amputations in the management of CLTI, and describes the patients who should be offered primary amputation.
Head and Neck Microsurgeon Practice Patterns and Perceptions Regarding Venous Thromboembolism Prophylaxis
Authors: Venkatesh Kaushik P. , Ambani Shoshana W. , Arakelians Aris R.L. , Johnson Jonas T. , Solari Mario G.
Published: May 2020

Background Patients undergoing head and neck (H&N) microvascular reconstruction comprise a population at high risk for venous thromboembolism (VTE). Free flap and VTE thromboprophylaxis may coincide but tend to vary from surgeon to surgeon. This study identifies VTE prophylaxis patterns and perceptions among H&N microsurgeons in the United States.

Methods An online survey on VTE prophylaxis practice patterns and perceptions was emailed to 172 H&N microsurgeons in the United States using an anonymous link.

Results There were 74 respondents (43% response rate). These surgeons completed residencies in otolaryngology (59%), plastic surgery (31%), and oral maxillofacial surgery (7%). Most underwent fellowship training (95%) and have practiced at an academic center (97%) for at least 6 years (58%), performing an average of 42 ± 31 H&N free flap cases per year (range = 1–190). Most adhered to general VTE prophylaxis guidelines (69%) while 11% did not and 20% were unsure. Nearly all surgeons (99%) would provide prophylactic anticoagulation, mostly in the form of subcutaneous heparin (51%) or enoxaparin (44%); 64% additionally used aspirin, while 4% used aspirin alone. The majority of surgeons (68%) reported having postoperative VTE complications, with six surgeons (8%) reporting patient deaths due to pulmonary embolism. A third of the surgeons have encountered VTE prophylaxis-related adverse bleeding events, but most still believe that chemoprophylaxis is important for VTE prevention (92%). While 35% of surgeons were satisfied with their current practice, most would find it helpful to have official prophylactic anticoagulation guidelines specific to H&N free flap cases.

Conclusion The majority of microsurgeons experienced postoperative VTE complications after H&N free flap reconstruction despite the routine use of prophylactic anticoagulation. Though bleeding events are a concern, most surgeons believe chemoprophylaxis is important for VTE prevention and would welcome official guidelines specific to this high-risk population.
A posteriori error estimate in fluid simulations of turbulent edge plasmas for magnetic fusion in tokamak using the data mining iPoPe method
Authors: Cartier-Michaud T. , Galassi D. , Ghendrih Ph. , Tamain P. , Schwander F. , Serre E.
Published: May 2020

Progressing toward more reliable numerical solutions in the simulation of plasma for magnetic confinement fusion has become a critical issue for the success of the ITER operation. This requires developing rigorous and efficient methods of verification of numerical simulations in any relevant flow regimes of the operation. This paper introduces a new formulation of the Projection on Proper elements method, namely, the independent Projection on Proper elements method to quantify the numerical error by performing a data-driven identification of the mathematical model from the simulation outputs. Based on a statistical postprocessing of the output database, the method provides a measure of the error by estimating the distance between the (numerical) effective and (analytical) theoretical weights of each operator implemented in the mathematical model. The efficiency of the present method is illustrated on turbulent edge plasma simulations based on a drift-reduced Braginskii fluid model in realistic magnetic geometries. The results show the effective order of the numerical method in these multiscale flow regimes as well as the values of the plasma parameters which can be safely simulated with respect to a given discretization. In this sense, the method goes one step further than the Method of Manufactured Solution recently introduced in fusion, and provides an efficient verification procedure of the numerical simulations in any regimes, including turbulent ones that could be generalized to other scientific domains.
Influence of air impurities on the transition from a symmetric discharge to an asymmetric discharge in an atmospheric pressure helium diffuse dielectric barrier discharge
Authors: Hong Ya , Ning Wenjun , Dai Dong , Zhang Yuhui
Published: May 2020

The transition from a symmetric and single period (SP1) discharge to an asymmetric and single period (AP1) discharge is a typical nonlinear dynamical phenomenon in dielectric barrier discharges (DBDs) at atmospheric pressure. Considering the presence of air impurities in practical applications which is always unavoidable due to the air-tightness of the DBD reactor, a one-dimensional fluid model with 26 species and 154 reactions is developed to thoroughly investigate the influence of air impurities on the transition from the SP1 discharge to the AP1 one in atmospheric DBDs in a helium mixture with air impurities. In our study case, simulation results show that the discharge experiences the transitions from the SP1 discharge to the AP1 one twice when the air impurity content is increased from 1 to 200 ppm. The first transition (appearing around 60–100 ppm) is due to the additional pre-ionization electrons generated by the higher rate of Penning ionization in the pre-ionization phase, whereas the second transition (occurring around 170–200 ppm) is due to the reduction of the residual electron density which is caused by the decrease in the electron production rates and the change in applied voltage polarity. In addition, as the air impurity content exceeds a certain amount, the rates of Penning ionization are the result of the competition between the increase in the mole fractions of N2 and O2 and the decrease in the molar fractions of He* and He2*.
Band engineering in epitaxial monolayer transition metal dichalcogenides alloy MoxW1−xSe2 thin films
Authors: Xie Xuedong , Ding Yunjing , Zong Junyu , Chen Wang , Zou Jingyi , Zhang Haijun , Wang Can , Zhang Yi
Published: May 2020

The direct bandgap transition and spin–orbit-coupling-induced spin-splitting in monolayer transition metal dichalcogenides MX2 (M = Mo, W; X = S, Se, Te) show great application potential in high-efficient optoelectronic devices and valleytronics and, thus, have attracted enormous research interest in recent years. Various MX2 monolayers usually show a distinct bandgap and spin-splitting size. Here, we realized the molecular beam epitaxial growth of monolayer MoxW1−xSe2 alloys with a controllable stoichiometric ratio x. Combining with the in situ angle-resolved photoemission spectroscopic and x-ray photoemission spectroscopic measurements, we determined the evolution of the valence band dispersion and the spin-splitting size with the change in the Mo ratio x. We found that the energy difference of both the valence band between the Γ and K points and the spin-splitting size at the K point reduce monotonically with the increasing Mo ratio x. The growth of MoxW1−xSe2 monolayer alloys and the method to control the stoichiometric ratio of Mo/W atoms provide an effective way to engineer the band structures in the two-dimensional MX2 materials.
A new perspective on lone pair dynamics in halide perovskites
Authors: Remsing Richard C. , Klein Michael L.
Published: May 2020

Halide perovskites form the foundation of an emerging class of materials for broad application in renewable and sustainable applications, including photocatalysis and solar energy harvesting. These materials exhibit beneficial photophysical properties, including bandgaps suitable for solar energy harvesting and efficient charge screening that underlies efficient charge carrier separation and resistance to defects. For organic–inorganic hybrid perovskites, these benefits are thought to arise, in part, from dipolar molecular cations that can reorient in response to charged particles and defects. In this work, we provide a similar perspective for inorganic metal halide perovskites, which do not contain molecular species with permanent dipoles. We discuss how lone pair electrons lead to dipolar ions that exhibit dynamics in analogy with traditional molecular plastic crystals and hybrid perovskites. We argue that further understanding these electronic plastic crystal motions with first principles simulations and synchrotron scattering can help create a basic understanding of photophysical properties of metal halide perovskites and inform the design of advanced functional materials.
Transition probabilities in the two-level quantum system with PT-symmetric non-Hermitian Hamiltonians
Authors: Ohlsson Tommy , Zhou Shun
Published: May 2020

We investigate how to define in a consistent way the probabilities of the transitions between the “flavor” states of the two-level quantum system, which is described by a non-Hermitian but parity and time-reversal (PT) symmetric Hamiltonian. Explicit calculations are carried out to demonstrate the conservation of probability if a proper definition of the final state is adopted. Finally, this formalism is applied to two-flavor neutrino oscillations νμ → νμ and νμ → ντ in vacuum, where the exact PT symmetry requires the vacuum mixing angle to be maximal, which is compatible with current neutrino oscillation experiments. A possible generalization to the three-flavor case is briefly discussed.
Two-way interaction between river and deployed cross-flow hydrokinetic turbines
Authors: Gauvin-Tremblay Olivier , Dumas Guy
Published: May 2020

This study focuses on the interaction between the water free surface, the riverbed, and some Darrieus-type hydrokinetic turbines deployed in river flows. As turbines offer a resistance to the flow, they affect the upcoming velocity, which in turn affects their performance. The proximity of the neighboring deformable free surface or rigid bed may also influence their power extraction. In this context, 2D and 3D URANS simulations of a cross-flow (H-Darrieus type) turbine are conducted with free-surface modeling and adapted boundary conditions allowing the capture of the interactions between the turbine and the resource. Different water depth immersions are considered in order to study local proximity effects. It is found, neglecting riverbed friction, that shallow immersion is detrimental to power extraction whereas bed proximity associated with deep immersion is favorable. This observation does not hold when considering a more realistic river with a velocity profile throughout the depth. Direction of rotation in high proximity cases also plays a role. Although the literature suggests a slight increase in power extraction with the Froude number, we find that when interaction with the resource is taken into account, the power extraction is rather independent of the Froude number for deep immersion or slightly decreasing for shallow immersion. Nonetheless, all the variations in power extraction reported in this study remain small compared to the ones associated with blockage effects. Finally, the shallow immersion case simulated in 3D behaves similarly to that simulated in 2D. Switching the orientation of the rotation axis from horizontal to vertical, despite changing the local interaction with the free surface, does not affect significantly the performance of the turbine.
Unsteady flow control of a plane diffuser based on a Karman-vortex generator
Authors: Yang Jinwen , Zhang Yufei , Chen Haixin , Fu Song
Published: May 2020

Implicit large-eddy simulation is employed to simulate the flow in an asymmetric plane diffuser at Re=9000. Flow separation exists near the throat and evolves to large-scale, unsteady separation in the expansion section and the downstream region. An unconventional flow control method, namely, a cylindrical Karman-vortex generator (KVG) with different sizes and locations that induces periodic spanwise vortex shedding, is set upstream of the throat to suppress the flow separation. An appropriately designed KVG can enhance the mixing of the outer flow and the low energy fluid near the wall region by the periodic shedding Karman-vortices, and effectively reduce the separation bubble size. For the present optimal case, the length and height of the separation bubble are decreased 50.4% and 90.9%, respectively. The static pressure recovery coefficient is also increased by about 50%. Moreover, the velocity and total pressure distributions at the end of the expansion section are more uniform with lower fluctuation in the case with KVG installed. An optimal KVG diameter DK is suggested to be 3–4% of the expansion section length LE. The gap ratio to the lower wall G/DK and the length ratio to the throat Lt/DK are suggested to be 2.0–3.0 and 5.0–10.0, respectively.
Inferring the magnetic anisotropy of a nanosample through dynamic cantilever magnetometry measurements
Authors: Yu Yang , Xu Feng , Guo Shanshan , Wang Ning , Zou Lvkuan , Wang Baomin , Li Run-Wei , Xue Fei
Published: May 2020

The magnetic anisotropy of bit-patterned media, such as a mesocrystal, is a key parameter in spintronics. Here, we utilize the high sensitivity of dynamic cantilever magnetometry to investigate the foundation of a mesocrystal, an individual CoFe2O4 pyramid nanocrystal. The magnetic anisotropy of the nanosample can be inferred through quantitatively correlating the main features in the evolution of the magnetic energy with frequency shifts in dynamic cantilever magnetometry measurements. Magnetometry data taken at 280 K exhibit hybrid magnetic anisotropy, including uniaxial anisotropy and cubic anisotropy. Low-temperature measurements further confirm the previously reported single-domain state and indicate that the cubic anisotropy is mainly magnetocrystalline anisotropy, while uniaxial anisotropy is likely to be induced by the interface between the CoFe2O4 pyramid and the BiFeO3 layer. The analysis provides an alternative interpretation for dynamic cantilever magnetometry data, which may extend the application of magnetometry.