bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation eines mHealth unterstützten Heimübungsprogramms für Menschen mit Kniearthrose (mhexos) – Bedienbarkeit, Erfahrungen von Nutzer*innen und Outcome
Authors: Schäfer Axel , Löffler-Idel Ingrid , Adelt Elisabeth , Fielder Christina , Reinhardt Angelika , Wilhelm Nathalie , Lochwitz Andreas , Paelke Volker
Published: February 2022

Hintergrund Kniearthrose ist einer der Hauptgründe für Behinderungen und Mobilitätseinschränkungen bei älteren Menschen, die mit Leid und hohen Krankheitskosten verbunden sind. Nicht operative Therapien wie Übungstherapie, Maßnahmen zur Steigerung der körperlichen Aktivität und zur Unterstützung des Selbstmanagements können Schmerzen verringern sowie die Funktion und gesundheitsbezogene Lebensqualität verbessern. Entsprechende Heimübungsprogramme sind ein wichtiger Baustein der Therapie, die Adhärenz ist jedoch oft nicht ausreichend. Digitale Gesundheitsanwendungen sind, insbesondere unter den Bedingungen der aktuellen COVID-19-Pandemie, eine vielversprechende Möglichkeit, um Barrieren zu überwinden.

Ziel Untersuchung der Implementierbarkeit eines mHealth-Heimübungsprogramms für Patient*innen mit Kniearthrose (mhexos) in Hinblick auf Bedienbarkeit, Erfahrungen von Nutzer*innen, Nutzungsverhalten und der Veränderung gesundheitsbezogener Endpunkte.

Methode Patient*innen mit Kniearthrose führten das mHealth Heimübungsprogramm mhexos 4 Wochen lang durch. Die Umsetzung erfolgte über ein Tablet mit insgesamt 39 Übungsvideos zur Kräftigung, Balance und Koordination, die in 3 Schwierigkeitsstufen konfiguriert werden können. Über eine App wurden Daten zur Schmerzintensität und der selbst wahrgenommenen Belastung erfasst. Es wurden leitfadengestützte Interviews durchgeführt und Fragebögen zur Erfassung der Bedienbarkeit und der Erfahrungen der Nutzer*innen sowie zu gesundheitsbezogenen Endpunkten an 2 Messzeitpunkten eingesetzt.

Ergebnisse Es wurden 10 Patient*innen und 7 Therapeut*innen eingeschlossen. Das mHealth-Heimübungsprogramm konnte in die Praxis und den Alltag der Teilnehmenden implementiert werden. Die App wurde überwiegend als bedienungsfreundlich und motivierend eingeschätzt, die Therapietreue war mit einer Übungsfrequenz von 2,7 × pro Woche (SD 0,6) hoch. In den gesundheitsbezogenen Endpunkten zeigten sich im Interventionszeitraum kleine, klinisch und statistisch nicht signifikante Veränderungen.

Schlussfolgerung: mhexos scheint geeignet, Heimübungsprogramme für Menschen mit Kniearthrose unter den Rahmenbedingungen der Routineversorgung zu unterstützen. Für eine weitergehende Beurteilung der klinischen Wirksamkeit sind kontrollierte Studien nötig.
Grundlagen und Instrumente des klinischen Risikomanagements
Authors: Krukenkamp Sabine , Schwarz Yulia
Published: February 2022

Risiken im OP gibt es viele – manche davon können Patienten schwer schädigen. Um das zu verhindern, müssen Fehlerquellen identifiziert und Maßnahmen ergriffen werden. Unterstützen können hierbei das Critical Incident Reporting System, die Fehlermöglichkeits- und Einflussanalyse, Checklisten, das Beschwerdemanagement und klinische Behandlungspfade. Wir stellen Ihnen die wichtigsten Instrumente des klinischen Risikomanagements vor.
Das Alpha-Gal-Syndrom
Authors: Mülleneisen Norbert K. , Bergenroth Tanja , Salge Stephanie
Published: February 2022

Die Einschränkung der Lebensqualität bei Urtikaria ist stark abhängig vom subjektiven Empfinden und der Lokalisation der Quaddeln. Leitlinien sollten deshalb die Einteilung nach Einschränkung der Lebensqualität in Diagnostik und Therapie stärker berücksichtigen als die starre Einteilung nach akut und chronisch an Hand der Sechs-Wochen-Grenze.
Medikamentöse Behandlung des benignen Prostatasyndroms: Was gibt’s Neues?
Authors: Michel Martin C. , Madersbacher Stephan
Published: February 2022

Auch Jahrzehnte nach der Einführung der 5α-Reduktasehemmer und der α1-Adrenozeptor-Antagonisten ergeben sich praxisrelevante, neue Daten zu deren erwünschten und unerwünschten Wirkungen. Einige der neuen Befunde sind ihrer Natur nach ernst zu nehmen, aber bisher unzureichend abgesichert wie z.B. ein Zusammenhang mit Depressionen oder Demenz. Verschiedene Kombinationsbehandlungen wurden getestet. Dabei war die Kombination der Monotherapie häufig statistisch signifikant überlegen, aber der Unterschied bewegte sich meistens in der Größenordnung von 1 IPSS-Punkt, was Zweifel an der klinischen Relevanz der Beobachtungen im Gruppenmittel lässt. Die neuen Daten ermöglichen eine weiter individualisierte BPS-Behandlung, machen die individuelle Nutzen-Risiko-Abwägung aber komplizierter.
Early Neurologic Complications and Long-term Neurologic Outcomes of
Extracorporeal Membrane Oxygenation Performed in Children
Authors: Azapagasi Ebru , Kendirli Tanıl , Tunçer Gokcen Oz , Perk Oktay , Isikhan Selen Yilmaz , Tıras Serap Teber , Eyileten Zeynep , Ince Erdal , Uysalel Adnan , Akar Ahmet Rüçhan
Published: February 2022

Background We aimed at evaluating acute neurologic complications (ANC) and
clinical outcome at a 2-year follow-up in children after extracorporeal membrane
oxygenation (ECMO).

Methods We conducted a single-center, retrospective review of our patient
cohort aged between 1 month and 18 years at the time of ECMO support (between
June 2014 to January 2017). Outcome analysis included ANC and their clinical
consequences.The Pediatric Overall Performance Category (POPC) and Pediatric
Cerebral Performance Category (PCPC) were used for neurologic assessment
performed at discharge from the hospital and at 2nd year follow-up.

Results There were 35 children who required ECMO. The median ECMO time was
9 days (range 2–32 days). Decannulation from ECMO was achieved in
68.6% of patients, and overall, 42.8% survived (15 patients),
The incidence of ANC in the surviving patients was 40% (6 children). ANC
were intracranial hemorrhage, seizures, cerebral infarction, which occurred in
one, two and three of the 15 surviving patients respectively (6.6, 13.3 and
20%). A higher rate of organ failure was related to death
(p=0.043), whereas duration on ECMO was a risk factor for the
development of ANC (p<0.05). At hospital discharge, the 14 patients
evaluated had normal development or -mild disability in 73.2%, and at
the 2-year follow-up, 93.4% had these scores.

Conclusion Children who receive ECMO have a risk to develop ANC, which was
related to the length of ECMO treatment, while survival was related to less
organ failure, Long-term neurological outcome was good in our patient
cohort.
Stereoselective Synthesis of Dispirooxindoles Incorporating Pyrrolo[2,1-a]isoquinoline via [3+2] Cycloaddition of Azomethine Ylides with a Thiazolo[3,2-a]indole Dipolarophile
Authors: Deepthi Ani , Thomas Noble V. , Meenakshy C. B. , Leena Sruthi S.
Published: February 2022

Highly regio- and stereoselective synthesis of dispiropyrrolo[2,1-a]isoquinoline-oxindoles have been developed by the one-pot three component reaction of isatins, 1,2,3,4-tetrahydroisoquinoline (THIQ), and a thiazolo[3,2-a]indole derivative. The reaction proceeds regioselectively through an exo-Re face approach of the in situ generated tetrahydroisoquinolium ylides towards the dipolarophile yielding the corresponding [3+2] cycloadducts in excellent yields and stereoselectivity.
A Global Systematic Review of Hepatitis C Elimination Efforts through Micro-Elimination
Authors: Lazarus Jeffrey V. , Picchio Camila A. , Byrne Christopher J. , Crespo Javier , Colombo Massimo , Cooke Graham S. , Dore Gregory J. , Grebely Jason , Ward John W. , Dillon John F.
Published: February 2022

Microelimination targets specific subpopulations and/or geographic settings for hepatitis C virus (HCV) elimination. This review reports on global HCV microelimination literature published from 2013 to 2020. Data were extracted from publications to report a score based on the four key components defining microelimination. Sustained virologic response (SVR) and treatment initiation proportions were calculated for each manuscript and grouped means of these estimates were compared depending on microelimination score and care setting. A total of 83% of the studies were from high-income settings and mainly included people who use drugs or those incarcerated. Among manuscripts, 18 had “low” microelimination scores, 11 had “high” scores, and the differences in mean proportion who initiated treatment and achieved SVR between low and high score groups were statistically significant. Microelimination can be a useful complementary strategy for driving engagement in HCV treatment and cure. Our analysis suggests that adhering to more of the core microelimination components can improve outcomes. This study is registered with Prospero, registration identification: CRD42020175211.
Prognosis of 22- and 23-Gestational-Week-Old Infants at Our Facility: A Retrospective Cohort Study
Authors: Yanagisawa Toshimitsu , Nakamura Tomohiko , Kokubo Masayo
Published: February 2022

Objective This study aimed to compare inborn infants aged 22 and 23 gestational weeks at our hospital to assess for differences in survival and long-term prognosis.

Study Design We retrospectively analyzed 22- and 23-gestational-weeks-old infants born in our hospital between January 2011 and December 2018. The prognosis of inborn infants in Japan was also calculated using the Neonatal Research Network of Japan (NRNJ) data during the same period.

Results The survival rates at our institution's neonatal intensive care unit discharge, including stillbirth, were 72 and 89% at 22 and 23 gestational weeks, respectively. The mortality rate and neurodevelopmental impairment (NDI) rate at 3 years of age, including stillbirth, were 58 and 32% at 22 and 23 weeks, respectively. Cerebral palsy, mental developmental retardation, visual impairment, and hearing impairment defined NDI. The prognosis at our hospital was better than the average calculated using NRNJ data. Survival rates varied among facilities, and some facilities had survival rates similar to that of our hospital.

Conclusion The prognosis of 22-gestational-week-old inborn infants was inferior to that of 23 gestational weeks in our institution but was better than previously reported. If aggressive treatment is provided, survival without sequelae can be fully expected even for 22-gestational-week-old infants.

Key Points
Danish Validation of a Retronasal Olfactory Powder Test and Development of a Novel Quick Retronasal Olfactory Test
Authors: Niklassen Andreas Steenholt , Sakthivel Sukanya , Fjaeldstad Alexander Wieck , Ovesen Therese
Published: February 2022

Introduction Quality of life is closely linked to retronasal olfactory function. Familiarity with odors vary, so tests need validation. Testing can be time-consuming, so a quick test and a thorough test are needed for clinical and research settings.

Objectives The objectives of this study were to validate the original retronasal powder olfactory test in a Danish population and to develop a novel quick retronasal test for easy application.

Methods Ninety-seven participants were included in the study, 59 healthy controls and 38 patients with olfactory impairment. The retronasal test was modified by substituting unfamiliar odors and descriptors and validated with a criterion of correct identification rate of 50% in the original test and 90% in the quick test. Items with over 90% correct identification rate in the modified original test were included in the quick test, resulting in a 10-item test.

Results The modified retronasal olfactory test achieved good test characteristics, with a 10th percentile cut-off value of 13: sensitivity was 88.9%, specificity 83.0%, positive predictive value 78%, negative predictive value 91.7%, and the receiver operating characteristics area under the curve (ROC-AUC) was 0.86. The quick test achieved acceptable test characteristics, with a 10th percentile cut-off value of 8.2: sensitivity was 72.2%, specificity 90.6%, positive predictive value 83.9%, negative predictive value was 82.8%, and ROC-AUC 0.81.

Conclusion Validation of both tests demonstrated satisfactory accuracy. We recommend the quick test for screening purposes, and the modified original version for a thorough evaluation. The tests are easily implemented as they are easy to understand and very affordable.
Pulmonary Oncology—Scope of the Pulmonologist
Authors: Tandon Sandeep , Biraris Pavankumar , Bhaskar Maheema
Published: February 2022

The International Agency for Research on Cancer GLOBOCAN project has predicted that India's cancer burden will nearly double in the next 20 years, from slightly more than a million new cases in 2012 to more than 1·7 million by 2035. In India, chronic respiratory diseases have emerged as a leading health care burden with chronic obstructive pulmonary disease (COPD) being the second leading cause of deaths and disability-adjusted life years. Patients with COPD are 6.35 times more likely to develop lung cancer. The deadly dual epidemic of “chronic respiratory diseases and cancer” warrants not only prevention but also creating an increased awareness among oncologists as well as pulmonologists to enable early diagnosis and treatment. It would be incorrect to assume that the scope of a pulmonologist in oncology is just diagnosing and treating lung cancer or prescribing chemotherapy for lung cancer. There is a larger world full of opportunities beyond that, and we look at the pulmonologist as a member of a multidisciplinary oncology team working together with the surgical, radiation, and medical oncologist and ancillary specialties to address all the issues highlighted earlier that are faced in oncology practice. The current exposure to pulmonary oncology and related complications during postgraduate training for respiratory medicine in India is limited. It is necessary not only to educate the pulmonologist on their role in an oncology setup but also to increase the awareness across all oncology specialties regarding the pulmonologist's contribution in management of the cancer patient. In this review, written based on our experience gained in our pulmonology service in our tertiary oncology center, we have tried to portray the wide role of the pulmonologist in oncology. We have realized that what is lacking is the basic awareness regarding the above potential, both among pulmonologists and oncologists. Our mission is to take this message across specialists in India, highlighting how we can work synergistically in the fight against cancer.
Neuropsychiatric Treatment Approaches for Functional Neurological Disorder: A How to Guide
Authors: Finkelstein Sara A. , Adams Caitlin , Saxena Aneeta , Perez David L. , Tuttle Margaret
Published: February 2022

There is a growing body of knowledge regarding management of functional neurological disorder (FND). The aim of this article is to guide the clinician through FND clinical management, from delivery of the diagnosis, to creation of a biopsychosocially-informed treatment plan, to troubleshooting common issues that arise throughout longitudinal care. We review the evidence and core principles of both rehabilitative therapies (physical therapy, occupational therapy, and speech and language therapy) and psychological therapies for the treatment of FND, and discuss the benefits of engaging a multidisciplinary and interdisciplinary team. The optimal timing of specific therapeutic interventions is also discussed, emphasizing a patient-centered perspective. Resources for further reading, for both patients and clinicians, are provided throughout. Additional research is needed to further optimize the therapeutic approach to patients with FND, including the need to develop novel treatments for those that do not positively respond to currently available interventions.
Comparison of Recovery Profiles of Patients Undergoing Endoscopic Lumbar Discectomy under Desflurane, Propofol, or Sevoflurane Anesthesia: A Randomized, Prospective, Clinical, Comparative Study
Authors: Verma Amit Kumar , Haldar Rudrashish , Srivastava Shashi , Das Kuntal Kanti , Mishra Prabhaker
Published: February 2022

Background Agents like propofol, sevoflurane, and desflurane having rapid revival of psychomotor and cognitive functions translating into reliable anesthetic recovery are chosen for day care procedures. This prospective randomized comparative study was undertaken to compare the psychomotor and cognitive functions of patients undergoing discectomy under different anesthetic strategies.

Methods Seventy-five adult American Society of Anesthesiologists grade I and II patients being operated for endoscopic lumbar discectomy under different anesthetic regimens were enrolled and were subjected to Trieger Dot Test (TDT), Digit Symbol Substitution Test (DSST), and Mini-Mental State Examination (MMSE) preoperatively at specified intervals postoperatively. There emergence and early recovery times, complications, and satisfaction levels were also noted.

Results No difference was found in the postoperative TDT and DSST and MMSE scores among the groups at all the time points (15 minutes, 3 minutes, 1 hour, 2 hours, 3 hours, and 4 hours). TDT and DSST demonstrated a tendency to return to baseline by 2nd and 3rd hour postoperatively. Emergence and early recovery times were earlier in the inhalation groups (p 0.005 and 0.007, respectively). Time required to attain a Modified Aldrete Score of 9, complications, and observed side effects were similar among the groups.

Conclusion Patients in the three groups had similar impairments in their psychomotor and cognitive functions which recovered at comparable time periods postoperatively. Emergence and early recovery were, however, faster in the desflurane group.
Hybrid shield for microwave single-photon counter based on a flux qubit
Authors: Lyakhno V. Yu. , Turutanov O. G. , Boichenko A. P. , Shapovalov A. P. , Kalenyuk A. A. , Shnyrkov V. I.
Published: February 2022

A scenario of shielding and stabilization of magnetic and electromagnetic fields in the measuring volume occupied by a superconducting flux qubit is considered. The qubit is used as an artificial macroscopic atom with discrete energy levels in a counter of single photons of the microwave range. It is shown that a decrease in the amplitude of variations of the external magnetic field inside the 3-layer hybrid cylindrical shield, composed of superconducting and ferromagnetic cylinders with the diameter-to-length ratio of 1:5, provides high stability of the magnetic field. The absolute value of the magnetic field at the sample location is determined mainly by the magnetic flux captured by the superconductor shields during their superconducting transition. Although the magnetic field stability is more important than the field itself for the photon counter, the paper also discusses experimental methods for reducing the absolute field value in the hybrid shield.
Structural variety and stability of carbon honeycomb cellular structures
Authors: Diachenko D. G. , Krainyukova N. V.
Published: February 2022

A new synthesized carbon honeycomb allotrope reported previously, built from graphene nanoribbons connected by sp3-bonded carbon junction lines, forms a family of cellular structures with high porosity and sorption capacity. In this work we first propose a complete set of possible honeycomb structures of different wall chiralities both the armchair and zigzag types, including considered earlier only theoretically, for the structural analysis of such structures by means of the high-energy electron diffraction method. The “completeness” of the model set made it possible to obtain nearly perfect coincidence of the experimental and calculated diffraction intensities. The contribution of graphite fragments and random structures, also involved in the analysis, turned out to be zero. Only a limited number of honeycomb structures of different types almost ideally describes the experiment. Thus we conclude that polydomain structures corresponding to a set of basic models formed in this investigation rather than formations dominated by random structures. The samples under study have demonstrated the unique cellular stability since were stored in vacuum ∼4.5 months before the reported measurements. Along with the original results the history of the carbon honeycomb cellular structures is briefly presented.
Nonlinear dynamics of an integrable gauge-coupled exciton-phonon system on a regular one-dimensional lattice
Authors: Vakhnenko Oleksiy O.
Published: February 2022

A one-dimensional nonlinear dynamical system of intra-site excitations and lattice vibrations coupled via gauge-like mechanism is studied. The system admits the semi-discrete zero-curvature representation and therefore it proves to be integrable in the Lax sense. Relaying upon an appropriately developed Darboux–Bäcklund dressing technique the explicit four-component analytical solution to the system is found and analyzed in details. Due to mutual influence between the interacting subsystems the physically meaningful solution arises as the essentially nonlinear superposition of two principally distinct types of traveling waves. The interplay between the two typical spatial scales relevant to these traveling waves causes the criticality of system’s dynamics manifested as the dipole-monopole transition in the spatial distribution of intra-site excitations.
Suppression of superconductivity in YBa2Cu3O7−δ single crystals upon irradiation with fast electrons
Authors: Khadzhai G. Ya. , Sklyar V. V. , Vovk R. V.
Published: February 2022

The effect of irradiation with fast electrons on the conductivity in the basal plane of HTSC single crystals of YBa2Cu3O7−δ is studied. It was found that electron irradiation leads to significant degradation of the superconducting characteristics, up to the complete disappearance of superconductivity. It was detected that even a significant decrease in Tc with a noticeable increase in ρ in the temperature range of Tc−300 K is not accompanied by the appearance of an S-shaped dependence ρ(T). In this case, the dependences ρ(T) in the basal plane, measured after irradiation with low and medium doses, are satisfactorily described within the framework of the resonating valence bond theory.
Approach for flattening metal oxides in ultra-high vacuum preparation smooths rough surfaces
Authors: Liebendorfer Adam
Published: February 2022

Model drawing on oxygen chemical potential provides new way to better model on the atomic scale and enhance surface diffusion across several different metal oxide films.
Regulation of phase transition temperature and preparation for doping-VO2 smart thermal control films
Authors: Wu Jialiang , Tong Liping , Wang Huifen , Liu Gang , Fu Xuecheng , Fan Tongxiang
Published: February 2022

Vanadium dioxide (VO2) is considered one of the most promising smart thermal control materials due to its insulator-metal temperature (IMT) reversible phase transition, accompanied by large changes in its optical properties. However, as the crystal defects on IMT change and the optical property of VO2 is still unclear, the preparation of doped VO2 films by magnetron sputtering is still a great challenge. In this work, the IMT of 41 kinds of doping-VO2 systems were studied by high throughput calculation based on density functional theory (DFT). It was found that the IMT increased with the decrease of the β angle in M phase and expansion of cell volume difference of M-phase and R-phase for IIA elements, VIIA elements, transition elements, and rare earth element doped VO2, and increased with the increase of the β angle in M phase and a decrease of cell volume difference of M-phase and R-phase for IA, IVA, VA, and VIA element doped VO2. According to the rule, the IMT, electronic structures, and optical properties of W doped VO2 were studied based on DFT. The results show that IMT and bandgap decrease with the increase of W6+ ion concentration, which is due to the increased cell volume difference of M-phase and R-phase in W doped VO2; each doped atom can reduce the IMT of 20.2 °C, and the IMT of V0.98W0.02O2 is close to room temperature (Tc ≈ 27 °C). The rate of infrared emissivity (∆ɛ) of V0.98W0.02O2 is about 0.2 at 8–14 μm (0.088–0.155 eV) and the average solar absorption (αs) of M phase and R phase is about 0.53 and 0.59 at 0.3–1.5 μm (0.496–4.13 eV), respectively. Finally, radio frequency magnetron sputtering was used to achieve precise doping, which solved the problem of oxygen partial pressure in reactive magnetron sputtering, and V1-xWxO2 films with IMT close to room temperature and narrow hysteresis width were prepared. This is due to the fact that higher W doping content will greatly increase the density of defect-induced nucleation sites and promote nucleation. At the same time, the experimental results of IMT were consistent with the calculated results, which proved the reliability of the calculation. This will provide a theoretical basis for the development of new thermal control materials and a new method for the preparation of doping-VO2 films in the future.
Twelve tales in mathematical physics: An expanded Heineman prize lecture
Authors: Simon Barry
Published: February 2022

This is an extended version of my 2018 Heineman prize lecture describing the work for which I got the prize. The citation is very broad, so this describes virtually all my work prior to 1995 and some afterward. It discusses work in non-relativistic quantum mechanics, constructive quantum field theory, and statistical mechanics.
A 3D printed pure copper drift tube linac prototype
Authors: Mayerhofer M. , Mitteneder J. , Dollinger G.
Published: February 2022

Radio frequency cavities are among the most challenging and costly components of an accelerator facility. They are usually manufactured in individual parts, which are then joined by complex processes, e.g., several brazing steps. 3D printing has become an alternative to these conventional manufacturing methods due to higher cost efficiency, freedom in design, and recent achievement of high print quality for pure copper. A fully functional 3 GHz drift tube linac (DTL) prototype was 3D printed in one piece, made from pure copper by selective laser melting (SLM). To achieve a higher surface quality, the DTL geometry was optimized for the SLM process. The DTL design is related to the design of the DTL part of the side-coupled DTL modules used in linac-based proton therapy facilities. The quality factor (8750) and the shunt impedance per unit length (102mΩm) of the printed prototype are already comparable to traditionally manufactured DTL structures and can be further enhanced by surface treatments.
Electronic and ionic conductivity in β-Ga2O3 single crystals
Authors: Ghadbeigi Leila , Sun Rujun , Jesenovec Jani , Bhattacharyya Arkka , McCloy John , Krishnamoorthy Sriram , Scarpulla Michael A. , Sensale-Rodriguez Berardi
Published: February 2022

In this work, we quantify electronic and ionic contributions to conductivity in the bulk and depletion widths of back-to-back sputtered Pt Schottky contacts on single crystals of β-Ga2O3. We also demonstrate asymmetric changes to these contacts induced by DC bias at temperatures as low as 200 °C, which has obvious bearing on the performance and reliability of devices. Crystals, which were unintentionally doped, doped with Zr donors, and doped with Mg acceptors, were characterized from room temperature to 900 °C. Electrochemical impedance spectroscopy, current–voltage (IV), capacitance–voltage, and the Wagner DC polarization method were employed to characterize changes in conductivity, doping, and built-in potentials with temperature and bias. This work demonstrates that ionic conductivity can be on-par with electronic conductivity in multiple circumstances in bulk crystal samples and leads to changes in Schottky contacts with an applied bias. While it has not been demonstrated that these phenomena are endemic to all melt-grown β-Ga2O3 crystals and epitaxially grown layers were not investigated, these results highlight the importance of understanding and controlling ionic conductivity and defect reactions involving impurities and native defects to enable reliable and long-lived β-Ga2O3 power devices.
Dynamics and interactions of magnetically driven colloidal microrotors
Authors: Hernández Raúl Josué Hernández , Fischer Thomas M. , Tierno Pietro
Published: February 2022

We study the pair interactions between magnetically driven colloidal microrotors with an anisotropic shape. An external precessing magnetic field induces a torque to these particles spinning them at a fixed angular frequency. When pair of rotors approach each other, the anisotropic particles interact via dipolar forces and hydrodynamic interactions (HIs) excited by their rotational motion. For applied field spinning close to the magic angle, ϑm=54.7°, dipolar interactions vanish and the dynamic assembly of the pair is driven only by HIs. Further, we provide a theoretical description based on the balance between dipolar forces and HIs that allow understanding the role of anisotropy on the collective dynamics. Investigating microscopic colloidal rotors and understanding their collective dynamics are important tasks for both fundamental reasons, but also to engineer similar fluid stirrers that can be readily used for precise microscale operations or as microrheological probes.
Interferometric bunch length measurements of 3 MeV picocoulomb electron beams
Authors: Yang X. , Yu L. H. , Smaluk V. , Shaftan T. , Doom L. , Kosciuk B. , Cheng W. X. , Bacha B. , Padrazo D. , Li J. J. , Babzien M. , Fedurin M. , Carr G. L. , Zhu Y. M.
Published: February 2022

We report picosecond bunch length measurements using an interferometric method for a 3 MeV electron beam having bunch charge ranging from 1 to 14 pC. The method senses the single-cycle sub-terahertz (THz) pulse emitted by each electron bunch as coherent transition radiation which, in turn, is analyzed using a Michelson-type interferometer, forming an interferogram that is then processed to yield the nominal electron bunch length. This sub-THz coherent radiation intensity was measured using a quasi-optical detector (QOD) operated at room temperature. This experiment was quite challenging since the divergence angle of the sub-THz pulse emitted by the low-energy electron bunch exceeds ±10°, and its pulse energy at the entrance to the detector was as low as 100 pJ. When compared to a conventional helium-cooled silicon composite bolometer designed for frequencies above 0.5 THz, the QOD provided much better signal-to-noise ratio in the ∼80 GHz frequency range, which was critical for the successful measurement of the bunch length.
Possibility of the existence of a topological defect in dynamic deformation of the free-standing ultrathin silicon wafer during MeV ion irradiation
Authors: Minagawa Hideaki , Tsuchida Hidetsugu
Published: February 2022

We study the ion-irradiation-induced deformation of free-standing ultrathin Si wafers with a thickness of 8 μm. The time-response spectrum of the deformation was measured using a laser displacement meter with a time resolution of 1 ms. The results showed that the deformation appeared during irradiation and disappeared after irradiation. The deformation was composed of a fast deformation with a millisecond time constant and a slow deformation with a second time constant. We performed a model calculation to identify the deformation mechanisms. We found that the fast deformation originated from expansion or shrinkage of crystal lattice caused by beam heating and deduced that the slow deformation resulted from the topological defect formation in Si crystals. The relaxation time of the slow deformation is related to the coordination number of disappeared topological defects. In this experiment, we conclude that the deformation of Si crystals maintains reversible behavior in the formation of topological defects up to the coordination number 5.
Electron localization in periodically strained graphene
Authors: Giambastiani Davide , Colangelo Francesco , Tredicucci Alessandro , Roddaro Stefano , Pitanti Alessandro
Published: February 2022

Pseudo-magnetic field (PMF) in deformed graphene has been proposed as a promising and flexible method to quantum-confine electronic states and create gaps in the local density of states. Motivated by this perspective, we numerically analyze various different configurations leading to electronic localization and band flattening in periodically strained graphene. In particular, we highlight the existence of a fine structure in the pseudo-Landau levels confined in large-PMF regions, the emergence of states confined to PMF nodes as well as of snake-like orbits. In our paper, we further analyze the importance of the relative rotation and asymmetry of the strain lattice with respect to the atomic lattice and show how it can be used to modulate the PMF periodicity and to create localized orbits far from the strain points. Possible implementations and applications of the simulated structures are discussed.
Subband-resolved momentum-conserved resonant tunneling in monolayer graphene/h-BN/ABA-trilayer graphene small-twist-angle tunneling device
Authors: Seo Yuta , Masubuchi Satoru , Onodera Momoko , Zhang Yijin , Moriya Rai , Watanabe Kenji , Taniguchi Takashi , Machida Tomoki
Published: February 2022

We demonstrate twist-controlled resonant tunneling in a monolayer graphene (MLG)/hexagonal boron nitride (h-BN)/ABA-stacked trilayer graphene (TLG) van der Waals (vdW) junction, in which MLG and TLG flakes are aligned with a small twist angle θ of ∼1.05° between their crystallographic orientations through a thin h-BN barrier. Owing to the small interlayer twist, resonant tunneling attributed to the conservation of momentum and energy was observed between the single linear band of MLG and multiple subbands of TLG. We show that different subbands of TLG—bilayer-graphene-like subbands and a MLG-like subband—exhibit distinctly different resonant tunneling behaviors. Therefore, we demonstrate subband-resolved resonant tunneling. This technique provides a method to determine band parameters (Slonczewski–Weiss–McClure parameters) and probes the band dispersion of different two-dimensional materials by utilizing a MLG electrode.
Oxygen NMR of high-density and low-density amorphous ice
Authors: Hoffmann Lars , Beerwerth Joachim , Adjei-Körner Mischa , Fuentes-Landete Violeta , Tonauer Christina M. , Loerting Thomas , Böhmer Roland
Published: February 2022

Using oxygen-17 as a nuclear probe, spin relaxometry was applied to study the high-density and low-density states of amorphous ice, covering temperatures below and somewhat above their glass transitions. These findings are put in perspective with results from deuteron nuclear magnetic resonance and with calculations based on dielectrically detected correlation times. This comparison reveals the presence of a wide distribution of correlation times. Furthermore, oxygen-17 central-transition echo spectra were recorded for wide ranges of temperature and pulse spacing. The spectra cannot be described by a single set of quadrupolar parameters, suggesting a distribution of H–O–H opening angles that is broader for high-density than for low-density amorphous ice. Simulations of the pulse separation dependent spin-echo spectra for various scenarios demonstrate that a small-step frequency diffusion process, assigned to the presence of homonuclear oxygen–oxygen interactions, determines the shape evolution of the pulse-separation-dependent spectra.
Validation study on a toroidal approximation-based capillary force model in the discrete element method simulation
Authors: Tamura Kotaro , Mori Yuki , Takabatake Kazuya , Sakai Mikio
Published: February 2022

Comprehension of wet particle behavior is of great importance in science and engineering. In the past two decades, modeling and simulation for wet particles have been extensively studied because of their various industrial applications. The discrete element method (DEM) is extensively employed to simulate the wet particle behavior. To calculate the wet particle behavior, several capillary force models have been developed so far. Roughly speaking, the capillary force models are classified into two types, namely, the analytical model and the geometrical approximation model. The analytical model is most frequently employed because of its simplicity, though only a small amount of the liquid volume is applicable. The geometrical approximation model has significant advantages because of no theoretical limitation of the liquid volume as well as its high accuracy. Incidentally, the geometrical approximation model usually expresses the liquid bridge shape by the toroidal approximation. However, validation tests for the geometrical approximation model have hardly been performed due to difficulty in incorporating the complex algorithm into the DEM. From the background, this paper aims to prove the superiority and adequacy of the geometrical approximation model in the DEM simulation for wet particles. First, the superiority of the geometrical approximation model to the analytical model is examined in a two-body system. Afterward, the following two types of validation tests are performed: granular collapse and wet powder mixing in a twin-screw kneader. In the granular collapse, the liquid content is set to be less than 4 vol. %. In the twin-screw kneader system, the liquid content is more than 5 vol. %. Through the validation tests, the adequacy of the geometrical approximation model in the DEM is proved because of the agreement between the computational and experimental results in the above systems. Consequently, this study will significantly contribute to a better understanding of wet particle behavior in science and engineering.
Rock salt-type HoO epitaxial thin film as a heavy rare-earth monoxide ferromagnetic semiconductor with a Curie temperature above 130 K
Authors: Amrillah Tahta , Oka Daichi , Shimizu Hirokazu , Sasaki Satoshi , Saito Daichi , Kaminaga Kenichi , Fukumura Tomoteru
Published: February 2022

Ho monopnictides (HoPn: Pn = N, P, As, Sb, and Bi) and monochalcogenides (HoCh: Ch = S, Se, and Te) are known to possess a nontrivial magnetic structure, while solid-phase HoO has not been synthesized yet. In this study, a rock salt-type HoO epitaxial thin film was grown by using the pulsed laser deposition method, which had a bandgap of 0.11 eV and tunable electrical conduction via its oxygen nonstoichiometry. Its Curie temperature, above 130 K, was much higher than those of HoPn and HoCh, most likely due to an enhanced direct exchange interaction. Similar to HoPn and HoCh, a HoO thin film showed a metamagnetic behavior below the Curie temperature in spite of its dominant ferromagentic ordering.
UREMP, RO-REMP, and OO-REMP: Hybrid perturbation theories for open-shell electronic structure calculations
Authors: Behnle Stefan , Fink Reinhold F.
Published: February 2022

An accurate description of the electron correlation energy in closed- and open-shell molecules is shown to be obtained by a second-order perturbation theory (PT) termed REMP. REMP is a hybrid of the Retaining the Excitation degree (RE) and the Møller–Plesset (MP) PTs. It performs particularly encouragingly in an orbital-optimized variant (OO-REMP) where the reference wavefunction is given by an unrestricted Slater determinant whose spin orbitals are varied such that the total energy becomes a minimum. While the approach generally behaves less satisfactorily with unrestricted Hartree–Fock references, reasonable performance is observed for restricted Hartree–Fock and restricted open-shell Hartree–Fock references. Inclusion of single excitations to OO-REMP is investigated and found—as in similar investigations—to be dissatisfying as it deteriorates performance. For the non-multireference subset of the accurate W4-11 benchmark set of Karton et al. [Chem. Phys. Lett. 510, 165–178 (2011)], OO-REMP predicts most atomization and reaction energies with chemical accuracy (1 kcal mol−1) if complete-basis-set extrapolation with augmented and core-polarized basis sets is used. For the W4-11 related test-sets, the error estimates obtained with the OO-REMP method approach those of coupled-cluster with singles, doubles and perturbative triples [CCSD(T)] within 20%–35%. The best performance of OO-REMP is found for a mixing ratio of 20%:80% MP:RE, which is essentially independent of whether radical stabilization energies, barrier heights, or reaction energies are investigated. Orbital optimization is shown to improve the REMP approach for both closed and open shell cases and outperforms coupled-cluster theory with singles and doubles (CCSD), spin-component scaled Møller-Plesset theory at second order (SCS-MP2), and density functionals, including double hybrids in all the cases considered.
Thermal holographic patterns for ultrasound hyperthermia
Authors: Andrés Diana , Vappou Jonathan , Jiménez Noé , Camarena Francisco
Published: February 2022

Holograms can shape wavefronts to produce arbitrary acoustic images. In this work, we experimentally demonstrate how acoustic holograms can produce controlled thermal patterns in absorbing media at ultrasonic frequencies. Magnetic resonance imaging (MRI)-compatible holographic ultrasound lenses were designed by time-reversal methods and manufactured using 3D-printing. Several thermal holographic patterns were measured using MRI thermometry and a thermographic camera in gelatin-milk phantoms and in an ex vivo liver tissue. The results show that acoustic holograms enable spatially controlled heating in arbitrary regions. Increasing the temperature using low-cost and MRI-compatible holographic transducers might be of great interest for many biomedical applications, such as ultrasound hyperthermia, where the control of specific thermal patterns is needed.
Infrared frequency comb spectroscopy of CH2I2: Influence of hot bands and pressure broadening on the ν1 and ν6 fundamental transitions
Authors: Roberts Frances C. , Lehman Julia H.
Published: February 2022

Direct frequency comb spectroscopy was utilized to measure the vibrational absorption spectrum of diiodomethane, CH2I2, from 2960 to 3125 cm−1. The data were obtained using a CH2I2 concentration of (6.8 ± 1.3) × 1015 molecule cm−3 and a total pressure of 10–300 mbar with either nitrogen or argon as the bath gas. The rovibrational spectra of two fundamental transitions, ν6 and ν1, were recorded and analyzed. We suggest that a significant contribution to the observed congested spectra is due to the population in excited vibrational states of the low energy ν4 I–C–I bend, resulting in transitions 6104nn and 1104nn, where the integer n is the initial vibrational level v = 1–5. PGOPHER was used to fit the experimental spectrum, allowing for rotational constants and other spectral information to be reported. In addition, it was found that the peak widths for the observed transitions were limited by pressure broadening, resulting in a pressure broadening parameter of (0.143 ± 0.006) cm−1 atm−1 by N2 and (0.116 ± 0.006) cm−1 atm−1 by Ar. Further implications for other dihaloalkane infrared spectra are discussed.
Applicability of multipole decomposition to plasmonic- and dielectric-lattice resonances
Authors: Han Aoxue , Moloney Jerome V. , Babicheva Viktoriia E.
Published: February 2022

Periodic nanoparticle arrays have attracted considerable interest recently since the lattice effect can lead to spectrally narrow resonances and tune the resonance position in a broad range. Multipole decomposition is widely used to analyze the role of the multipoles in the resonance excitations, radiation, and scattering of electromagnetic waves. However, previous studies have not addressed the validity and accuracy of the multipole decomposition around the lattice resonance. The applicability of the exact multipole decomposition based on spherical harmonics expansion has not been demonstrated around the lattice resonance with the strong multipole coupling. This work studies the two-dimensional periodic arrays of both plasmonic and dielectric nanospheres and compares the multipole decomposition results with the analytic ones around their lattice resonances. We study both the effective polarizabilities of multipoles and the scattering spectra of the structures. The analytical results are calculated from the coupled dipole–quadrupole model. This study demonstrates that the exact multipole decomposition agrees well with the numerical simulation around lattice resonances. Only a small number of multipoles are required to represent the results accurately.
Influence of water on the microscopic dynamics of 1-butyl-3-methylimidazolium tetrafluoroborate studied by means of quasielastic neutron scattering
Authors: Ruiz-Martín M. D. , Qureshi N. , González M. A. , Ollivier J. , Frick B. , Farago B.
Published: February 2022

We present a systematic study on the effect of water on the microscopic dynamics of 1-butyl-3-methylimidazolium tetrafluoroborate by means of quasielastic neutron scattering. By mixing the ionic liquid with either heavy or light water, the different contributions to the quasielastic broadening could be identified and treated separately. This study was performed at room temperature, which is more than 15 °C above the demixing line. Our results show that even small amounts of water accelerate the diffusion mechanisms considerably. While samples with small water percentage reveal a diffusion process confined within ionic liquid nanodomains, an admixture of more than 15 wt. % water relieves the confinement. Furthermore, the presence of two water species was identified: one behaving as free water, whereas the other was interpreted as a component bound to the ionic liquid motion. Based on the fact that water preferentially binds to the BF4 anion, which itself has a negligible contribution to the scattered intensity, our experiments reveal unprecedented information about the microscopic anion dynamics.
Interlayer Coulomb interaction in twisted bilayer graphene nanofragments characterized by the vibrational mode of Gr+ band
Authors: Lu Yirui , Yan Lei , Hussain Shafqat , Sun Mengtao , Zhang Zhenglong , Zheng Hairong
Published: February 2022

Tip enhanced Raman spectra of AB-stacked bilayer graphene (BLG) and twisted bilayer graphene (TwBLG) nanofragments have been studied by using density functional theory. Different from a normal Raman spectrum of BLG, a unique Raman band Gr+ is observed in its tip enhanced Raman spectrum and assigned as a split of the G band. We attribute this split to the nonuniformity distribution of the charge on carbon atoms. Compared with BLG, the Gr+ band intensity of TwBLG is dramatically enhanced at a small twist angle and decreases with the angle increasing. Interlayer Coulomb interaction represented in the Gr+ mode of TwBLG matches well with the atom vibration strength distribution of the Gr+ band at different twist angles, and thereby the properties of the Gr+ band can be tuned by the twisted angle. The results may help to further understand the Raman spectra of TwBLG and provide deep insights for exploring vibrational modes of two-dimensional nanomaterials.