bluuebunny/crossref_metadata_2025 huggingface dataset:
SOS-Gruppe für Suchterkrankte
Authors: Huber Sergej
Published: January 2021

Die Abkürzung „SOS“ verbinden sicherlich die meisten mit einem Notsignal. In der Abteilung für Abhängigkeitserkrankungen am Pfalzklinikum haben die drei Buchstaben aber noch eine andere Bedeutung: School of Skills. In der SOS-Gruppe sollen Suchterkrankte Fertigkeiten und Fähigkeiten entwickeln, um nicht rückfällig zu werden. Unser Autor stellt das Konzept der Gruppe vor und gewährt Einblicke in den Skills-Koffer.
The N-Methyl-(2S,
4R)-trans-4-hydroxy-L-proline-Enriched Methanol Fraction from
Sideroxylon obtusifolium Shows an Anticonvulsant Activity Associated
with its Anti-inflammatory/Antioxidant Actions
Authors: de Aquino Pedro Everson Alexandre , Lustosa Ítalo Rosal , de Sousa Caren Nádia Soares , Chaves-Filho Adriano José Maia , Lima Francisco Arnaldo Viana , da Conceição Santos Alan Diego , Gramosa Nilce Viana , Silveira Edilberto Rocha , de Barros Viana Glauce Socorro
Published: January 2021

Epilepsy is a neurological disorder characterized by recurrent seizures,
resulting from excessive neuronal discharges. Sideroxylon
obtusifolium is used in Brazil for its
anti-inflammatory/antioxidant properties, known to be involved with
epilepsy. The anticonvulsant effects of the methanol fraction from S.
obtusifolium leaves, rich in
N-methyl-(2S,4R)-trans-4-hydroxy-L-proline,
were investigated on pilocarpine- and pentylenetetrazole-induced convulsion
models. Mice were pretreated with
N-methyl-(2S,4R)-trans-4-hydroxy-L-proline
(50, 100, 200 mg/kg, p.o.) and, 1 h later, by pilocarpine
(400 mg/kg, i.p.) or pentylenetetrazole
(80 mg/kg, i.p.). The animals were observed for latency to
the first convulsion and latency to death. Immediately after death, brain
areas from the pilocarpine groups were harvested for biochemical
measurements. The latency to the first convulsion and latency to death
increased after
N-methyl-(2S,4R)-trans-4-hydroxy-L-proline
treatment compared with the pilocarpine- or pentylenetetrazole-only groups.
In both convulsion models, sodium valproate (reference drug) was used as a
positive control. Additionally, the decreases in striatal dopamine and
3,4-dihydroxyphenylacetic acid contents observed in the pilocarpine-only
group were partially prevented in the
N-methyl-(2S,4R)-trans-4-hydroxy-L-proline-treated
groups. While brain gamma-aminobutyric acid and glutamate contents decreased
and increased, respectively, after pilocarpine only, these changes were also
prevented by
N-methyl-(2S,4R)-trans-4-hydroxy-L-proline.
Similarly,
N-methyl-(2S,4R)-trans-4-hydroxy-L-proline
reduced the brain oxidative stress by decreasing the levels of nitrite and
lipid peroxidation and increasing the glutathione content of the
pilocarpine-only group. The increases in hippocampal expressions for
interleukin 6, interferon-gamma, and glial fibrillary acidic protein, after
pilocarpine only, were decreased to normal levels by
N-methyl-(2S,4R)-trans-4-hydroxy-L-proline.
In conclusion, the study showed significant anticonvulsant effects for
N-methyl-(2S,4R)-trans-4-hydroxy-L-proline,
probably related to its anti-inflammatory/antioxidant properties.
N-Methyl-(2S,4R)-trans-4-hydroxy-L-proline
effects were potentiated by VPA (sodium valproate), thus it may also
interact with the GABAergic system, as we had recently shown.
Die dentogene Sinusitis
Authors: Abrams Jürgen
Published: January 2021

In den letzten Jahren wird eine steigende Anzahl odontogener Entzündungen der Kieferhöhle beobachtet. Voraussetzung für eine bakterielle Infektion der Kieferhöhle ist die Perforation der Schneider’schen Membran. Pathogenetisch ist die ostiomeatale Einheit durch die vom Kieferhöhlenboden aufsteigende Infektion erst sekundär involviert. Wichtig sind neben der Anamnese bildgebende Verfahren, wobei der hochauflösenden CT und der DVT wegen der 3-dimensionalen Auflösung eine besondere Aufgabe zukommt. Eine zahnärztliche Röntgenaufnahme oder eine zahnärztliche Untersuchung zur Diagnostik ist in vielen Fällen nicht ausreichend. Aufgrund der Anatomie sind vor allem die Molaren als Auslöser einer dentogenen Sinusitis anzusehen. Das Keimspektrum ist polymikrobiell mit einer Dominanz von Anaerobiern. Therapeutisch favorisieren wir die 1-zeitige Operation mit Sanierung des zugrunde liegenden Prozesses und funktioneller Nebenhöhlenchirurgie. Auch in der Implantologie kann die funktionelle Nebenhöhlenchirurgie einen wesentlichen Beitrag zur Sanierung entzündlicher Komplikationen leisten.
Prävalenz und Versorgung der Posttraumatischen Belastungsstörung in Deutschland: Eine bundesweite Auswertung von Krankenkassendaten aus den Jahren 2008 und 2017
Authors: Bachmann Christian J. , Czwikla Jonas , Jacobs Hannes , Fegert Jörg M. , Hoffmann Falk
Published: January 2021

Ziel der Studie Gewinnung von Daten zur Prävalenz sowie medizinischen und psychotherapeutischen Versorgung von Menschen mit PTBS in Deutschland.

Methodik Aus Sekundärdaten der BARMER wurde die Prävalenz von PTBS-Diagnosen (ICD-10: F43.1) sowie psychiatrischen Komorbiditäten, Psychotherapie und Pharmakotherapie für diese Versichertengruppe abgeleitet. Ergänzend wurden Prävalenztrends (2008 vs. 2017) berechnet.

Ergebnisse Im Jahr 2017 lag die PTBS-Diagnoseprävalenz bei 0,7 % (Frauen: 0,9 %; Männer: 0,4 %); gegenüber 0,3 % in 2008. 74,4 % aller Versicherten mit PTBS-Diagnose erhielten ambulante Psychotherapie, 43,6 % erhielten Antidepressiva (meistverordnet: Venlafaxin) und 14,4 % Antipsychotika (häufigste Substanz: Quetiapin).

Schlussfolgerung Im untersuchten Zeitraum hat sich die Diagnosehäufigkeit von PTBS mehr als verdoppelt. Sie liegt jedoch weiterhin unter der in epidemiologischen Studien ermittelten Prävalenz, was auf Potenzial für eine verbesserte diagnostische Erkennung von PTBS hindeutet.
Synthesis of 1,2,3-Triazole-Fused Indole Derivatives via Copper-Catalyzed Cascade Reaction
Authors: Zhou Fengtao , Zhang Qiuyu , Majeed Kashif , Liu Bangjie
Published: January 2021

A copper-catalyzed tandem reaction has been developed for the synthesis of 1,2,3-triazole-fused indole derivatives. This protocol allowed us to access a wide range of 1,2,3-triazole-fused indole derivatives in moderate to excellent yields. The 1,2,3-triazole-fused indole derivatives emit blue and greenish light when excited at 365 nm. The products were further explored for their quantum efficiency and photophysical properties.
Homeopathic Rhus toxicodendron Induces Cell Adhesions in the Mouse Pre-osteoblast Cell Line MC3T3-e1
Authors: Oh Young Soo , Chae Soo Chul , Kim Hwan , Yang Hun Ji , Lee Kyung Jin , Yeo Myeong Gu
Published: January 2021

Background Rhus toxicodendron (R. tox) has been used as a homeopathic remedy for the treatment of inflammatory conditions. Previously, we reported that R. tox modulated inflammation in the mouse chondrocyte and pre-osteoblastic MC3T3-e1 cell line. During the inflammatory process, cells adhere to the extracellular matrix (ECM) and then migrate to the inflammation site. We examine here the process of cell adhesion in MC3T3-e1 cells after their stimulation with homeopathic R. tox.

Methods For the cell–substrate adhesion assay, the cultured MC3T3-e1 cells were trypsinized, starved for 1 h in serum-free media, and plated onto culture plates coated with fibronectin (FN), 30c R. tox or gelatin, respectively. The cells were allowed to adhere for 20 min incubation and unattached cells were washed out. Adherent cells were measured using the water-soluble tetrazolium salt-8 assay. The intracellular signals after stimulation of R. tox were examined by analyzing the tyrosine phosphorylation of focal adhesion kinase (FAK), Src kinase, and Paxillin using immunoblot assay. Formation of focal adhesion (FA, an integrin-containing multi-protein structure that forms between intracellular actin bundles and the ECM) was analyzed by immunocytochemistry using NIH ImageJ software.

Results Cell adhesion increased after stimulation with R. tox (FN, 20.50%; R. tox, 44.80%; and gelatin, 17.11% vs. uncoated cells [control]). Tyrosine phosphorylation of FAK, Paxillin, and Src increased compared with that of gelatin when stimulated with R. tox. Additionally, R. tox-stimulated cells formed many FAs (number of FAs per cell, 35.82 ± 7.68) compared with gelatin-stimulated cells (number of FAs per cell, 19.80 ± 7.18) and exhibited extensive formation of actin stress fibers anchored by FAs formed at the cell periphery.

Conclusion Homeopathic R. tox promotes the formation of cell adhesions in vitro.
Relationship between Whole Blood Viscosity and Lesion Severity in Coronary Artery Disease
Authors: Ceyhun Gökhan , Birdal Oğuzhan
Published: January 2021

Objective This article investigates the relationship of fractional flow reserve (FFR) with whole blood viscosity (WBV) in patients who were diagnosed with chronic coronary syndrome and significant stenosis in the major coronary arteries and underwent the measurement of FFR.

Material and Method In the FFR measurements performed to evaluate the severity of coronary artery stenosis, 160 patients were included in the study and divided into two groups as follows: 80 with significant stenosis and 80 with nonsignificant stenosis. WBVs at low shear rate (LSR) and high shear rate (HSR) were compared between the patients in the significant and nonsignificant coronary artery stenosis groups.

Results In the group with FFR < 0.80 and significant coronary artery stenosis, WBV was significantly higher compared with the group with nonsignificant coronary artery stenosis in terms of both HSR (19.33 ± 0.84) and LSR (81.19 ± 14.20) (p < 0.001). In the multivariate logistic regression analysis, HSR and LSR were independent predictors of significant coronary artery stenosis (HSR: odds ratio: 1.67, 95% confidence interval: 1.17–2.64; LSR: odds ratio: 2.46, 95% confidence interval: 2.19–2.78). In the receiver operating characteristic (ROC) curve analysis, when the cutoff value of WBV at LSR was taken as 79.23, it had 58.42% sensitivity and 62.13% specificity for the prediction of significant coronary artery stenosis (area under the ROC curve: 0.628, p < 0.001).

Conclusion WBV, an inexpensive biomarker that can be easily calculated prior to coronary angiography, was higher in patients with functionally severe coronary artery stenosis, and thus could be a useful marker in predicting the hemodynamic severity of coronary artery stenosis in patients with chronic coronary syndrome.
Validity and Usefulness of YouTube Videos Related to Endoscopic Transsphenoidal Surgery for Patient Information
Authors: Levin Marc , Wu Vincent , Lee Daniel J. , Cusimano Michael D. , Lee John M.
Published: January 2021

Objectives This article evaluates the completeness and accuracy of YouTube videos related to endoscopic transsphenoidal surgery (ETS) as a source for patient information.

Design YouTube was searched using relevant terms pertaining to ETS. Videos were evaluated independently by two physician reviewers experienced in ETS. Video demographics including uploader source along with validity scores based on predetermined checklists were captured.

Setting Internet.

Participants Not applicable.

Main Outcome Measures A novel ETS scoring checklist, the modified DISCERN criteria, and Journal of the American Medical Association (JAMA) benchmark score were used to measure completeness and accuracy of videos. video power index (VPI) was calculated to reflect popularity. Intraclass correlation coefficient was calculated for rater agreement.

Results Seventy-nine videos were included in final scoring and analysis. The ETS score, DISCERN, JAMA, and mean VPI across all included videos were 5.0 ± 2.7, 2.4 ± 0.83, 2.19 ± 0.62, and 8.92 ± 18.1, respectively. Based on the ETS score checklist, 31 (39%) of the videos were rated as poor, 30 (38%) were moderately useful, 17 (22%) were useful, and 1 (1%) was exceptional. There was a significant positive correlation between the ETS, DISCERN, and JAMA scores (p < 0.001), but no correlation with VPI and the validity scores. There were no significant differences comparing validity scores based on the uploader source.

Conclusion YouTube videos related to ETS have limited usefulness and poor overall validity for patient information. Clinicians should direct patients to other validated sources of information and aim to improve the comprehensiveness of ETS-related videos.
Return to Work after Primary Total Knee Arthroplasty under the Age of 65 Years: A Systematic Review
Authors: Van Leemput Dries , Neirynck Jef , Berger Pieter , Vandenneucker Hilde
Published: January 2021

A growing number of patients undergoing total knee arthroplasty (TKA) is at working age and need to return to work (RTW) after surgery. The aim of this systematic review is to give an overview of the literature regarding RTW after TKA and beneficial and limiting factors influencing this process. A systematic search in four electronic databases was conducted in November 2019 to identify studies describing RTW after primary TKA in patients aged 65 years or younger. Study characteristics and data on work status before and after surgery were extracted. All studies were assessed for risk of bias. Fourteen studies published between 2009 and 2019 were included in this review, accounting for a total of 3,073 patients. The percentage of patients working after TKA ranged from 36 to 89%, and the fraction of patients working before and returning to work after surgery ranged from 40 to 98%. Mean time of RTW ranged from 7.7 to 16.6 weeks. Most important factors associated with a slower or no RTW were a more physical nature of employment and preoperative absence from work. The majority of patients undergoing TKA returned to work postoperatively. However, comparison between studies is seriously hampered by the wide variation regarding the definition and timeframe used to measure the work status. Therefore, standardized outcome measures for studies investigating RTW after TKA are warranted. We identify this review as level-I evidence (systematic review of level-I and level-II studies).
Use of a Spacer Block Tool for Assessment of Joint Line Position during Revision Total Knee Arthroplasty
Authors: Gungor Harun R. , Ok Nusret
Published: January 2021

There is a tendency of orthopaedic surgeons to elevate joint line (JL) in revision total knee arthroplasty (RTKA). Here, we ascertain the use of the spacer block tool (SBT) to determine JL more accurately for less experienced RTKA surgeons. To perform more precise restoration of JL, an SBT with markers was developed and produced using computer software and three-dimensional printers. The study was planned prospectively to include patients who received either condylar constrained or rotating hinge RTKA between January 2016 and December 2019. To determine JL, distance from fibular head (FH), adductor tubercle (AT), and medial epicondyle (ME) were measured on contralateral knee preoperative radiographs and on operated knee postoperative radiographs. Patients were randomized and grouped according to the technique of JL reconstruction. In Group 1, conventional methods by evaluating aforementioned landmarks and preoperative contralateral knee measurements were used to determine JL, whereas in Group 2, the SBT was used. The main outcome measure was the JL change in revised knee postoperatively in contrast to contralateral knee to compare effective restoration of JL between the groups. Twenty-five patients in Group 1 (3 males, 22 females, 72 years, body mass index [BMI] 32.04 ± 4.45) and 20 patients (7 males, 13 females, 74 years, BMI 30.12 ± 5.02) in Group 2 were included in the study. JL measurements for the whole group were FH-JL = 18.3 ± 3.8 mm, AT-JL = 45.8 ± 4.6 mm, and ME-JL = 27.1 ± 2.8 mm preoperatively, and FH-JL = 20.7 ± 4.2 mm, AT-JL = 43.4 ± 5.2 mm, and ME-JL = 24.7 ± 3.1 mm postoperatively. JL level differences in reference to FH, AT, and ME in Group 1 were 3.6 ± 3.1, 3.6 ± 3.5, and 3.4 ± 3.1 mm, respectively, and in Group 2 were 1.0 ± .0.9, 1.3 ± 1.3, and 1.1 ± 1.3 mm, respectively. There were statistically significant differences between the two groups in JL changes referenced to all of the specific landmarks (p < 0.05). The use of the SBT helped restore JL effectively in our cohort of RTKA patients. Therefore, this tool may become a useful and inexpensive gadget for less experienced and low-volume RTKA surgeons.
Alteplase and Adjuvant Therapies for Acute Ischemic Stroke
Authors: Gottula Adam L. , Barreto Andrew D. , Adeoye Opeolu
Published: January 2021

Acute ischemic stroke (AIS) is a time sensitive medical emergency and a leading cause of morbidity and mortality worldwide. Intravenous (IV) recombinant tissue plasminogen activator (IV alteplase) is currently the only proven effective medication for the treatment of AIS with promising adjuvant medications currently under investigation. Recent advances in endovascular thrombectomy have broadened therapeutic options in specific patient populations, with modern treatment strategies utilizing advanced imaging modalities to extend the window for treatment. In all cases, rapid treatment remains a priority. The future of IV alteplase and the changing standard for treatment of AIS remain unwritten with the increasing evidence for imaging selection for both endovascular thrombectomy and IV alteplase, while novel adjuncts are under investigation. In this article, we review the history of IV alteplase investigations for stroke, evidence for thrombectomy as an adjunct to IV alteplase, and the potential of novel adjuvant therapeutics currently under investigation.
The hygiene hypothesis, the COVID pandemic, and consequences for the human microbiome
Authors: Finlay B. Brett , Amato Katherine R. , Azad Meghan , Blaser Martin J. , Bosch Thomas C. G. , Chu Hiutung , Dominguez-Bello Maria Gloria , Ehrlich Stanislav Dusko , Elinav Eran , Geva-Zatorsky Naama , Gros Philippe , Guillemin Karen , Keck Frédéric , Korem Tal , McFall-Ngai Margaret J. , Melby Melissa K. , Nichter Mark , Pettersson Sven , Poinar Hendrik , Rees Tobias , Tropini Carolina , Zhao Liping , Giles-Vernick Tamara
Published: January 2021

The COVID-19 pandemic has the potential to affect the human microbiome in infected and uninfected individuals, having a substantial impact on human health over the long term. This pandemic intersects with a decades-long decline in microbial diversity and ancestral microbes due to hygiene, antibiotics, and urban living (the hygiene hypothesis). High-risk groups succumbing to COVID-19 include those with preexisting conditions, such as diabetes and obesity, which are also associated with microbiome abnormalities. Current pandemic control measures and practices will have broad, uneven, and potentially long-term effects for the human microbiome across the planet, given the implementation of physical separation, extensive hygiene, travel barriers, and other measures that influence overall microbial loss and inability for reinoculation. Although much remains uncertain or unknown about the virus and its consequences, implementing pandemic control practices could significantly affect the microbiome. In this Perspective, we explore many facets of COVID-19−induced societal changes and their possible effects on the microbiome, and discuss current and future challenges regarding the interplay between this pandemic and the microbiome. Recent recognition of the microbiome’s influence on human health makes it critical to consider both how the microbiome, shaped by biosocial processes, affects susceptibility to the coronavirus and, conversely, how COVID-19 disease and prevention measures may affect the microbiome. This knowledge may prove key in prevention and treatment, and long-term biological and social outcomes of this pandemic.
Glycoconjugate pathway connections revealed by sequence similarity network analysis of the monotopic phosphoglycosyl transferases
Authors: O’Toole Katherine H. , Imperiali Barbara , Allen Karen N.
Published: January 2021

Significance

Glycoconjugates and glycopolymers are involved in critical and varied biological functions across domains of life. Many of these complex molecules are biosynthesized via multistep membrane-associated pathways initiated through the action of phosphoglycosyl transferases (PGTs) and propagated by the collective action of glycosyl transferases. PGTs comprise two distinct superfamilies of enzymes, and, although the ubiquitous polytopic PGTs exhibit a familiar multi-transmembrane helical structure, the strictly prokaryotic monotopic PGTs feature a core signature structure with a reentrant membrane helix and a highly conserved soluble domain. In the presented analysis these motifs provide a “lynch pin” for positively identifying over 38,000 nonredundant superfamily members and their genome neighborhoods. From this foundation, fusions of the monotopic PGT reveal insight into pathway function and regulation.
Liquid-crystal-based topological photonics
Authors: Abbaszadeh Hamed , Fruchart Michel , van Saarloos Wim , Vitelli Vincenzo
Published: January 2021

Significance

Liquid crystals are complex fluids that combine a unique ability to manipulate light with the reconfigurability of soft materials. They are at the core of modern display technology. Here, we suggest that nematic liquid crystals can also be used as building blocks of topological materials key to realize protected unidirectional waveguides, sensors, and lasers. Building on recent advances in liquid-crystal technology, we propose that suitable spatial modulations of the nematic director field are sufficient to assemble topological photonic materials. These ideas pave the way for fully reconfigurable photonic devices based on topologically protected states.
The Life Cycle of Adpositions
Authors: Givón T.
Published: January 2021

Adpositions are used, universally, to mark the roles of nominal participants in the verbal clause, most commonly indirect object roles. Practically all languages seem to have such markers, which begin their diachronic life as lexical words -- in this case either serial verbs or positional nouns. In many languages, however, adpositions also seem to have extended their diachronic life one step further, becoming verbal affixes. The main focus of this book is the tail-end of the diachronic life cycle of adpositions. That is, the process by which, having arisen first as nominal-attached prepositions or post-positions, they wind up attaching themselves to verbs. Our core puzzle is thus fairly transparent: How and why should morphemes that pertain functionally to nominals, and begin their diachronic life-cycle as nominal grammatical operators, wind up as verbal morphology? While the core five chapters of this book focus on the rise of verb-attached prepositions in Homeric Greek, its theoretical perspective is broader, perched at the intersection of three closely intertwined core components of the study of human language: (a) the communicative function of grammar; (b) the balance between universality and cross-language diversity of grammars; and (c) the diachrony of grammatical constructions, how they mutate over time. While paying well-deserved homage to the traditional Classical scholarship, this study is firmly wedded to the assumption, indeed presupposition, that Homeric Greek is just another natural language, spoken before written, designed as an instrument of communication, and subject to the same universal constraints as all human languages. And further, that those constraints--so-called language universals--express themselves most conspicuously in diachronic change. Lastly, in analyzing the synchronic variation and text distribution of prepositional constructions in Homeric Greek, this study relies primarily on the theory-laden method of Internal Reconstruction.
The Role of Law Enforcement Officers in Responding to the Opioid Epidemic: A Qualitative Assessment
Authors: Pike Erika , Tillson Martha , Staton Michele , Webster J. Matthew
Published: January 2021

Background

Opioid-related overdose deaths continue to rise with the ongoing opioid epidemic. In response, changes in the role of law enforcement officers have included being trained to administer naloxone to reverse overdoses and offering navigation and referrals to substance use treatment.

Methods

This secondary data analysis includes qualitative data from law enforcement officers collected as part of a mixed-methods needs assessment from one Kentucky county. Law enforcement officers ( n = 151) responded to a confidential, online survey using Qualtrics and a subsample also completed a qualitative interview ( n = 6). Open-ended questions in the online survey and interviews included how the opioid epidemic has affected the individual's profession, specifically their role in reversing overdoses and providing referrals to individuals who misuse opioids.

Results

Law enforcement officers surveyed indicated that they have expanded their professional roles to include providing naloxone to reverse opioid overdoses and referrals. While their specific roles and duties have changed to include naloxone administration to reverse opioid overdoses and providing referrals, officers felt that this was just part of their job in responding to the needs of the community. Officers reported that they have learned how to use (99%) and carry naloxone (87%) to reverse opioid related overdoses. The majority (92%) reported providing referrals (e.g., treatment and harm reduction resources) to individuals who misuse opioids.

Conclusions

The opioid epidemic has changed the roles of law enforcement officers, including providing naloxone to reverse overdoses and referrals for treatment. Future research should continue to explore how substance misuse in the community changes the roles of law enforcement officers and how to best train and support officers as their roles evolve in response to these changes.
Computational approaches to non-convex, sparsity-inducing multi-penalty regularization
Authors: Kereta Željko , Maly Johannes , Naumova Valeriya
Published: January 2021

In this work we consider numerical efficiency and convergence rates for solvers of non-convex multi-penalty formulations when reconstructing sparse signals from noisy linear measurements. We extend an existing approach, based on reduction to an augmented single-penalty formulation, to the non-convex setting and discuss its computational intractability in large-scale applications. To circumvent this limitation, we propose an alternative single-penalty reduction based on infimal convolution that shares the benefits of the augmented approach but is computationally less dependent on the problem size. We provide linear convergence rates for both approaches, and their dependence on design parameters. Numerical experiments substantiate our theoretical findings.
Parametrix for the inverse source problem of thermoacoustic tomography with reduced data
Authors: Eller M , Kunyansky L
Published: January 2021

Our goal is to solve the inverse source problem of thermo- and photoacoustic tomography, with data registered on an open surface partially surrounding the source of acoustic waves. The proposed modified time reversal algorithm recovers the source term up to an infinitely smooth error term. Similarly to (Eller M et al 2020 Inverse Problems
36 085012), numerical simulations show that the error term is quite small in practical terms. Unlike the latter method, the present technique is applicable in the presence of a known variable speed of sound. It is also significantly more efficient from a computational standpoint. It can be implemented using either standard finite difference techniques or through methods based on separation of variables, that for special geometries yield extremely fast image reconstruction. We illustrate our results with numerical simulations in 2 and 3 spatial dimensions.
Tunable triple-band and broad-band convertible metamaterial absorber with bulk Dirac semimetal and vanadium dioxide
Authors: Ban Shihao , Meng Haiyu , Zhai Xiang , Xue Xiongxiong , Lin Qi , Li Hongjian , Wang Lingling
Published: January 2021

We propose a convertible metamaterial device with triple-band and broad-band characteristics based on bulk Dirac semimetal (BDS) and vanadium dioxide (VO2). When VO2 is in the fully insulating state, the proposed convertible device presents three distinctive absorption peaks in terahertz (THz) range with absorptance >98%. Absorptance spectra analysis shows a clear independence on the conductivity of VO2 when the device act as a triple-band absorber. When VO2 is in the fully metallic state, the convertible device expresses a broad-band absorption. In addition, this broad-band absorptivity can be continuously adjusted by changing the conductivity of VO2. Importantly, without making any changes to the structure parameters, the system exhibits unique convertible mechanism from triple-band to broad-band absorption. Electric field distributions are further discussed to explore the physical origin of this convertible absorber. Benefitting from the variable Fermi level of BDS, resonance frequency can be dynamically tuned. This design approach combined the use of BDS and VO2 not only paves a new way to realize a convertible absorber from triple-band to broad-band absorption, but also enables us to control the resonance frequency and absorption intensity in THz range. It is believed that the tunable converter provides plentiful applications such as modulator, energy harvesting and optic-electro switches.
Realizing the stable spectrum in four-chromatic white organic light-emitting diodes by controlling the positions of various emitters in the bipolar interlayer
Authors: Li Jun , Chen Tianqing , Yang Jie , Cao Jin
Published: January 2021

Maintaining a stable spectrum in white organic light-emitting diodes (WOLEDs) with multi-emissive layers (EMLs) remains a challenge. Herein, four-chromatic (blue–green–red–orange) WOLED with stable spectrum based on ultrathin EMLs and mixed bipolar interlayers was fabricated. We discovered that the locations of various color EMLs in the bipolar interlayers are essential for achieving the stable spectrum. The direct carrier trapping effects which destabilize the spectrum can be suppressed by placing red and green EMLs with both hole and electron traps in the middle of the bipolar interlayer and placing blue and orange EMLs with single-carrier traps on the two sides of the bipolar interlayer respectively. The resulting device exhibited the negligible color coordinate shifts of (0.008, 0.010) during the wide brightness range from 1000 cd m−2 to 10 000 cd m−2. Moreover, a high color rendering index of approximately 90 was obtained simultaneously. Our work demonstrated a significant method to achieve stable spectra in multi-EML WOLEDs based on bipolar interlayer.
Impedimetric characterization of normal and cancer cell responses after nano-pulse stimulation
Authors: Zhang Long , Shi Fukun , Guo Jinsong , Wang Qun , Kolb Juergen F , Wang Weidong , Wu Xiaodong , Zhuang Jie
Published: January 2021

This work aimed to investigate the potential selective effects of nano-pulse stimulation (NPS) on adherent cancer and normal cells using impedance spectroscopy. A constant phase element was used to separate the impedance of electrode polarization from the overall measured impedance. Its amplitude was further related to cell-to-substrate distance, D
cs, which describes the gap between cells and substrate. Dielectric properties of subcellular components were extracted based on a single-shell dielectric model for individual cells and were consequently used to calculate the induced transmembrane potentials (TMPs). Afterward, a Cole–Cole model was utilized to represent the impedance of cell monolayers. The model parameter, R
0, representing resistance at low frequency, was related to the paracellular distance, D
cc. Results showed that cancer cells could suffer a higher degree of electroporation than normal cells when exposed to the same NPS. This selective NPS effect was reflected by a greater decrease of the Cole model parameter, α, and larger induced TMPs for cancer cells. D
cc was pulse number-dependent for both types of cells after exposure (four and eight pulses, 100 ns, 660 V). D
cs showed lingering effects even 24 h after exposure to 8 ns pulses for both cancer and normal cells, suggesting that intense NPS can induce long-term changes of the cell-to-substrate interface.
Combined SEM-CL and STEM investigation of green InGaN quantum wells
Authors: Ding B , Jarman J , Kappers M J , Oliver R A
Published: January 2021

The microstructure of green-emitting InGaN/GaN quantum well (QW) samples grown at different temperatures was studied using cross-section scanning transmission electron microscopy (STEM) and plan-view cathodoluminescence (CL). The sample with the lowest InGaN growth temperature exhibits microscale variations in the CL intensity across the sample surface. Using STEM analysis of such areas, the observed darker patches do not correspond to any observable extended defect. Instead, they are related to changes in the extent of gross-well width fluctuations in the QWs, with more brightly emitting regions exhibiting a high density of such fluctuations, whilst dimmer regions were seen to have InGaN QWs with a more uniform thickness.
Construction of a novel direct Z-scheme heterostructure consisting of ReS2 nanoflowers and In2S3 nanohoneycombs for improving photoelectrochemical performance
Authors: Wang Jiawei , Li Qiujie , Cheng Yufei , Chen Lida , Sun Qian , Zhao Junfeng , Fan Jun , Miao Hui , Hu Xiaoyun
Published: January 2021

In2S3 (β-In2S3), semiconducting chalcogenide with desirable physicochemical properties, has fascinated researchers in photoelectrochemistry. Because of its wide band gap, In2S3 can utilize solar energy below 600 nm. However, rapid photogenerated electron–hole recombination and low quantum efficiency have limited the practical application of In2S3 in this field. In a two-step in situ hydrothermal process we introduced a narrow band gap semiconductor (ReS2) below the In2S3 and constructed a direct Z-scheme heterostructure with nanoflower and honeycomb morphology. The formation of a direct Z-scheme heterostructure and coordination of the trap-like structure of the composite give a wider absorption range, higher migration and separation efficiency, and faster interfacial transfer speed than for pristine In2S3, and the photoelectrochemical performance is approximately three times better than that of pristine In2S3 at 1.23 V versus a reversible hydrogen electrode under sunlight. This method therefore provides a new prospect for optimizing the performance of In2S3 and applying the novel heterojunction.
Statistical analysis of the excited-state quantum phase transitions in the interacting boson model
Authors: Dong Wen-Ting , Zhang Yu , He Bing-Cheng , Pan Feng , Luo Yan-An , Draayer J P , Karampagia S
Published: January 2021

The spectral fluctuations and transition intensity fluctuations in the excited-state quantum phase transitions (ESQPTs) have been investigated within the framework of the interacting boson model (IBM) by adopting three statistical measures, including the nearest neighbor level spacing distribution P(S) measuring the chaoticity (regularity) in energy spectra, the Δ3(L) statistics of Dyson and Mehta measuring the spectral rigidity and the intensity distribution P(y) measuring the chaoticity (regularity) in B(E0) transitions. The results indicate that that the ESQPT as a function of the excitation energy may occur as a transition from regular (or semiregular) to highly chaotic if only the associated whole spectrum is chaotic, which fits most of the deformed situations in the IBM including those in the U(5)–SU(3) and SU(3)–O(6) transitional regions. Otherwise, the ESQPT will appear as a transition from regular (or semiregular) to regular such as the cases in the U(5)–O(6) transitional region or those on the ‘Alhassid–Whelan arc’, which represents a nearly regular parameter region connecting the U(5) and SU(3) limits in the IBM.
Cancellation of one-loop corrections to scalar masses in flux compactification with higher dimensional operators
Authors: Hirose Takuya , Maru Nobuhito
Published: January 2021

We further study the cancellation of the one-loop corrections to the scalar mass in a six dimensional SU(2) gauge theory with higher dimensional operators, which is compactified on a torus with magnetic flux. Higher dimensional operators also contribute to the corrections to the scalar mass nontrivially. We explicitly show by the diagrammatic calculations that the corrections are exactly canceled even with the leading terms of the higher dimensional operators.
Electric-field-generated topological states in a silicene nanotube
Authors: Cassiano J V V , Martins G B
Published: January 2021

Applying an electric field perpendicular to the axis of a silicene armchair nanotube allows us to numerically study the formation of eight topological edge states as silicene’s intrinsic spin–orbit gap is closed by the sublattice-staggered electrostatic potential created by the electric field. Following their evolution with electric field, it is revealed that, at very small fields, these eight states are very broad, spin-locked, and sublattice constrained, inheriting their properties from the K and K′ states in a silicene two-dimensional honeycomb lattice. Four of those states are centered at the very top of the nanotube and the other four states are centered at the very bottom. As the field increases, each state starts to become narrower and to spread its spectral weight to the other sublattice. With further increase of the field, each state starts to spatially split, while the sublattice spreading continues. Once the spectral weight of each state is distributed evenly among both sublattices, the state has also effectively split into two spatially disconnected parts, after which, further increasing of the field will spread apart the two halves, moving them to the lateral regions of the nanotube, at the same time that the state halves become narrower. This is consistent with the formation of topological edge states, which delimit four ribbon-like topologically different regions: top and bottom topologically trivial ‘ribbons’ (where the electric field has induced a topological phase transition) that are adjacent to two topologically nontrivial ‘ribbons’ located at opposing sides of the nanotube. We also briefly access the possibility of observing these edge states by calculating the electronic properties for an electric field configuration that can be more readily produced in the laboratory.
A fast and quantitative measurement of shear wave speed and attenuation using (cross) modal assurance criterion for acoustic radiation force elasticity imaging
Authors: Jiao Yang , Yang Chen , Xu Jie , Cheng Leilei , Tang Yujia , Cui Yaoyao
Published: January 2021

The measurement of shear wave speed (SWS) or attenuation in soft materials, especially in biological tissues, plays a crucial role in acoustic radiation force elasticity imaging which provides a quantitative measurement of elastic properties. In this study, with the first attempt to apply modal analysis theory to acoustic radiation force elasticity imaging, we propose a fast tracking algorithm based on the modal assurance criterion (MAC) including 2D SWS-MAC for SWS measurement and the signed cross modal assurance criterion (CrossMAC) for shear wave attenuation measurement. These approaches achieved high speedup with a framework of high-level parallelism. The FEM simulation results proved the accuracy of these two approaches. Phantom experiments showed that the 2D SWS-MAC approach had good consistency in SWS estimation compared to existing approaches and could accurately preserve the boundary contour of the inclusion with narrowed assurance intervals (quarter-width assurance intervals). An excised porcine liver experiment verified the effectiveness of shear wave attenuation estimation with Signed CrossMAC. These results demonstrate that the MAC based approaches improved both the shear wave motion measurement precision and the speedup rate of the measurement compared to conventional time domain cross-correlation or time-to-peak methods.
An inverse simulation for simultaneous identification of randomly oriented arbitrarily shaped particle size distribution and its degree of non-sphericity from spectral transmittance measurement
Authors: Islam Md Arafat , Qi Hong , Ren Ya-Tao , Zhang Jun-You
Published: January 2021

An experimental model is suggested and integrated with a numerical scheme for simultaneous identification of arbitrary shape particle size distribution (PSD) and its degree of non-sphericity present in a system. In this spectroscopic instrumentation, the transmittance intensity of light is measured by calculating the bulk absorption coefficient of randomly oriented arbitrarily shaped particles by adopting parameterized anomalous diffraction theory. The effects of reflection and refraction of arbitrary shapes of particles are also considered. Multi-wavelength transmittance signals (estimated and measured values) are used to fit the objective functions for the identification of target parameters. The unique feature of this simulation is the simultaneous identification of the joint function PSD and the shape perimeter of arbitrary particles using the joint log-normal distribution function. A probability-density-function-based ant colony optimization (PDF-ACO) algorithm is carried out for the inverse simulation. The parameters retrieved by the multi-wavelength transmittance signals show good agreement with the set original values of the target parameters. The robustness of the PDF-ACO algorithm could successfully keep the retrieval errors of the estimated parameters within the tolerable limit (error < 10%) even at high noise in the system.
Design of highly sensitive and selective ethanol sensor based on α-Fe2O3/Nb2O5 heterostructure
Authors: Khatoon Rabia , Rauf Sajid , Haq Mahmood Ul , Attique Sanam , Din Salah Ud , Ali Nasir , Guo Yichuan , Chen Hongwen , Tian Yang , Lu Jianguo
Published: January 2021

The introduction of heterostructures is a new approach in gas sensing due to their easy and quick transport of charges. Herein, facile hydrothermal and solid-state techniques are employed to synthesize an α-Fe2O3/Nb2O5 heterostructure. The morphology, microstructure, crystallinity and surface composition of the synthesized heterostructures are investigated by scanning electron microscope, transmission electron microscope, x-ray diffraction, x-ray photoelectron spectroscopy and Brunauer–Emmett–Teller analyses. The successful fabrication of the heterostructures was achieved via the mutual incorporation of α-Fe2O3 nanorods with Nb2O5 interconnected nanoparticles (INPs). A sensor based on the α-Fe2O3(0.09)/Nb2O5 heterostructure with a high surface area exhibited enhanced gas-sensing features, maintaining high selectivity and sensitivity, and a considerable recovery percentage towards ethanol gas. The sensing response of the α-Fe2O3(0.09)/Nb2O5 heterostructure at lower operating temperature (160 °C) is around nine times higher than a pure Nb2O5 (INP) sensor at 180 °C with the flow of 100 ppm ethanol gas. The sensors also show excellent selectivity, good long-term stability and a rapid response/recovery time (8s/2s, respectively) to ethanol. The superior electronic conductivity and upgraded sensitivity performance of gas sensors based on the α-Fe2O3(0.09)/Nb2O5 heterostructure are attributed due to its unique structural features, high specific surface area and the synergic effect of the n–n heterojunction. The promising results demonstrate the potential application of the α-Fe2O3(0.09)/Nb2O5 heterostructure as a good sensing material for the fabrication of ethanol sensors.
Compliance current controlled volatile and nonvolatile memory in Ag/CoFe2O4/Pt resistive switching device
Authors: Munjal Sandeep , Khare Neeraj
Published: January 2021

We report on the resistive memory effects of a Ag/CoFe2O4/Pt device and a deterministic conversion between volatile and nonvolatile resistive switching (RS) memory through the tuning of current compliance (I
CC). For the smaller I
CC (10−4 A) the device exhibits volatile RS behavior with an atomically sized conducting filament showing the quantum conductance. For an intermediate I
CC (10−2 A) nonvolatile bipolar RS behavior is observed, which could originate from the formation and rupture of filament consisting of Ag ions. The high resistance state (HRS) of the device shows a semiconducting conduction mechanism, whereas the low resistance state (LRS) was found to be Ohmic in nature. The temperature dependent resistance studies and magnetization studies indicated that the electrochemical metallization plays a dominant role in the resistive switching process for volatile and nonvolatile modes through the formation of Ag conducting filaments. For higher I
CC (10−1 A) the device permanently switches to LRS. The irreversible RS memory behaviors, observed for higher I
CC, could be attributed to the formation of a thick and stable conducting channel formed of oxygen vacancies and Ag ions. The compliance current controlled resistive switching modes with a large memory window make the present device a potential candidate to pave the way for future resistive switching devices.
A new approach for synthesizing plasmonic polymer nanocomposite thin films by combining a gold salt aerosol and an atmospheric pressure low-temperature plasma
Authors: Nadal Elie , Milaniak Natalia , Glenat Hervé , Laroche Gaétan , Massines Françoise
Published: January 2021

The proof of the concept of a new, onestep and safe by design process to synthesize metal-polymer nanocomposites thin films on a large surface is presented. It is based on the injection of an aerosol of a solution of metal (gold) salts dissolved in a polymerizable solvent (isopropanol) into an argon atmospheric pressure dielectric barrier discharge. The main novelty of this method resides in the fact that the nanoparticles are formed in situ, inside the plasma reactor, in the gas phase. Consequently, the nanoparticle synthesis and deposition are concomitant with the solvent polymerization used to produce the matrix, which makes it possible to obtain homogeneous layers of non-agglomerated nanoparticles (NPs) with high NPs density. By toggling between low and high-frequency discharges, gold/polymer nanocomposites with different morphologies and optical properties are synthesized. The effect of the concentration of gold in the aerosol and the gas residence time in the plasma as well as the ratio of high and low-frequency discharge and their repetition rate are presented. The thin films are systematically characterized by AFM and UV–visible spectroscopy to analyze their morphologies along with their plasmonic resonances.
Antisolvent engineering on low-temperature processed CsPbI3 inorganic perovskites for improved performances of solar cells
Authors: Han Bingquan , Zhang Lei , Cao Yuwei , Li Benyi , Liu Zhiyuan , Xu Lingbo , Wang Peng , Lin Ping , Wu Xiaoping , Cui Can
Published: January 2021

CsPbI3 inorganic perovskites with ideal bandgap and much enhanced thermal stability compared with organic−inorganic hybrid perovskites, have attracted much interest in the field of solar cells. The performances of solar cells highly depend on the quality of perovskite films, yet the research on fabrication methods of inorganic perovskites is far below that of organic–inorganic hybrid counterparts. Antisolvent engineering is a widely used method in controlling the morphology and crystallinity of organic–inorganic hybrid perovskites. Its effect varies with parameters such as the physicochemical properties of antisolvents and the compositions of perovskite precursors. Specially, there lacks a comprehensive study comparing different antisolvents used in low-temperature processed CsPbI3 from dimethylammonium-based precursors. In this work, we used three different antisolvents to control the growth of CsPbI3 films in a low-temperature (<200 °C) processed procedure and systematically compared the properties of resultant films. The green antisolvent ethyl acetate (EA) engineered CsPbI3 films exhibit improved morphology and crystallinity as well as reduced defects, compared with the counterparts processed without antisolvent or those with widely employed toxic antisolvents toluene and chlorobenzene. The EA antisolvent engineering results in efficient CsPbI3 perovskite solar cells with a champion power conversion efficiency of 8.8%. Our work thus provides a green and viable way to prepare high quality CsPbI3 perovskite films for optoelectronic applications.