bluuebunny/crossref_metadata_2025 huggingface dataset:
Higher MLCT lifetime of carbene iron(ii) complexes by chelate ring expansion
Authors: Reuter Thomas , Kruse Ayla , Schoch Roland , Lochbrunner Stefan , Bauer Matthias , Heinze Katja
Published: July 2021

High octahedricity and rigidity enable the high 9.2 ps 3MLCT lifetime of the iron(ii) complex [Fe(dpmi)2]2+ possessing only two carbene donor sites.
Acceptor-regulated luminescence in carbazole-based charge transfer complexes
Authors: Wang Si-Si , Li Kechang , Ma Xiaohui , Xue Pengchong
Published: July 2021

A dicarbazole derivative and two acceptors could formed 1D mixed stacking columns in their charge transfer co-crystals. Moreover, the LUMO energy levels of the acceptors determine the fluorescence colors of the co-crystals.
Down and up conversion luminescence of the lead-free organic metal halide material: (C9H8NO)2SnCl6·2H2O
Authors: Saidi Lamia , Samet Amira , Dammak Thameur , Pillet Sebastien , Abid Younes
Published: July 2021

Optical properties of hybrid organic metal halide material (C9H8NO)2SnCl6·2H2O.
Thermal and photo stability of all inorganic lead halide perovskite nanocrystals
Authors: Xing Ke , Cao Sheng , Yuan Xi , Zeng Ruosheng , Li Haibo , Zou Bingsuo , Zhao Jialong
Published: July 2021

We shed light on the thermal and photo stability of all inorganic lead halide perovskite nanocrystals from the perspective of surface ligands and structure composition in order to promote their application from the laboratory to the market.
Clay nanotube-metal core/shell catalysts for hydroprocesses
Authors: Glotov Aleksandr , Vutolkina Anna , Pimerzin Aleksey , Vinokurov Vladimir , Lvov Yuri
Published: July 2021

Natural clay nanotube-metal based core/shell catalysts for hydroprocesses: structural design, synthesis, applications.
Surface matrix curing of inorganic CsPbI3 perovskite quantum dots for solar cells with efficiency over 16%
Authors: Jia Donglin , Chen Jingxuan , Mei Xinyi , Fan Wentao , Luo Shuo , Yu Mei , Liu Jianhua , Zhang Xiaoliang
Published: July 2021

Herein, a “surface matrix curing” (SMC) strategy is introduced to restore the surface matrix of CsPbI3 PQDs for improving the photovoltaic performance of PQD solar cells.
Convenient C(sp3)–H bond functionalisation of light alkanes and other compounds by iron photocatalysis
Authors: Jin Yunhe , Zhang Qingqing , Wang Lifang , Wang Xinyao , Meng Changgong , Duan Chunying
Published: July 2021

A practical and green iron-catalyzed photoredox system for C–H functionalization of ethane, propane, and other light alkanes was developed.
Application of metal–organic frameworks as an alternative to metal oxide-based photocatalysts for the production of industrially important organic chemicals
Authors: Belousov Artem S. , Suleimanov Evgeny V.
Published: July 2021

This critical review reports the heterogeneous photocatalytic production of industrially important organic chemicals with a particular focus on the use of metal–organic frameworks as an alternative to metal oxide-based photocatalysts.
Ball-milling synthesis of sulfonyl quinolines via coupling of haloquinolines with sulfonic acids
Authors: Liu Xiao-Wen , Wang Jia-Qian , Ma Hui , Zhu Qi , Xie Long-Yong
Published: July 2021

A practical and environment-friendly methodology for the construction of sulfonyl quinolines through ball milling promoted coupling of haloquinolines with sulfonic acid under metal-, base-, solvent- and additive-free conditions was developed.
Current understanding of nanoparticle toxicity mechanisms and interactions with biological systems
Authors: Garcés Mariana , Cáceres Lourdes , Chiappetta Diego , Magnani Natalia , Evelson Pablo
Published: July 2021

Nanotechnology is an emerging science involving the manipulation of matter on the nanometer scale.
The degradation of methylene blue dye using copper-doped hydroxyapatite encapsulated into polycaprolactone nanofibrous membranes
Authors: Alrafai H. A. , Ali Al-Ahmed Zehbah , Ahmed M. K. , Afifi M. , Shoueir Kamel R. , Abu-Rayyan Ahmed
Published: July 2021

Methylene blue is degraded under visible light irradiation in the presence of the nanofibrous membranes of PCL containing modified HAP with different contents of Cu ions.
Synthesizable nanoparticle eigenshapes for colloidal crystals
Authors: Geng Yina , van Anders Greg , Glotzer Sharon C.
Published: July 2021

Eigenshapes are nanoparticle shapes that minimize the free energy of a target structure for fixed thermodynamic conditions. We determine eigenshapes for several structures using Alchemical Monte-Carlo (Alch-MC), inverse design techniques.
Carrier extraction from metallic perovskite oxide nanoparticles
Authors: McDonald Calum , Ni Chengsheng , Švrček Vladimir , Macias-Montero Manuel , Velusamy Tamilselvan , Connor Paul A. , Maguire Paul , Irvine John T. S. , Mariotti Davide
Published: July 2021

We observe the extraction of carriers excited between two types of bands in the perovskite oxide, Sr-deficient strontium niobate (Sr0.9NbO3).
Prostasin regulates PD-L1 expression in human lung cancer cells
Authors: Chen Li-Mei , Chai Julius C. , Liu Bin , Strutt Tara M. , McKinstry K. Kai , Chai Karl X.
Published: July 2021

The serine protease prostasin is a negative regulator of lipopolysaccharide-induced inflammation and has a role in the regulation of cellular immunity. Prostasin expression in cancer cells inhibits migration and metastasis, and reduces epithelial–mesenchymal transition. Programmed death-ligand 1 (PD-L1) is a negative regulator of the immune response and its expression in cancer cells interferes with immune surveillance. The aim of the present study was to investigate if prostasin regulates PD-L1 expression. We established sublines overexpressing various forms of prostasin as well as a subline deficient for the prostasin gene from the Calu-3 human lung cancer cells. We report here that PD-L1 expression induced by interferon-γ (IFNγ) is further enhanced in cells overexpressing the wildtype membrane-anchored prostasin. The PD-L1 protein was localized on the cell surface and released into the culture medium in extracellular vesicles (EVs) with the protease-active prostasin. The epidermal growth factor-epidermal growth factor receptor (EGF-EGFR), protein kinase C (PKC), and mitogen-activated protein kinase (MAPK) participated in the prostasin-mediated up-regulation of PD-L1 expression. A Gene Set Enrichment Analysis (GSEA) of patient lung tumors in The Cancer Genome Atlas (TCGA) database revealed that prostasin and PD-L1 regulate common signaling pathways during tumorigenesis and tumor progression.
Unravelling the tangled web of hypertension and cancer
Authors: Sionakidis Aristeidis , McCallum Linsay , Padmanabhan Sandosh
Published: July 2021

Cardiovascular disease remains the primary cause of mortality globally, being responsible for an estimated 17 million deaths every year. Cancer is the second leading cause of death on a global level with roughly 9 million deaths per year being attributed to neoplasms. The two share multiple common risk factors such as obesity, poor physical exercise, older age, smoking and there exists rare monogenic hypertension syndromes. Hypertension is the most important risk factor for cardiovascular disease and affects more than a billion people worldwide and may also be a risk factor for the development of certain types of cancer (e.g. renal cell carcinoma (RCC)). The interaction space of the two conditions becomes more complicated when the well-described hypertensive effect of certain antineoplastic drugs is considered along with the extensive amount of literature on the association of different classes of antihypertensive drugs with cancer risk/prevention. The cardiovascular risks associated with antineoplastic treatment calls for efficient management of relative adverse events and the development of practical strategies for efficient decision-making in the clinic. Pharmacogenetic interactions between cancer treatment and hypertension-related genes is not to be ruled out, but the evidence is not still ample to be incorporated in clinical practice. Precision Medicine has the potential to bridge the gap of knowledge regarding the full spectrum of interactions between cancer and hypertension (and cardiovascular disease) and provide novel solutions through the emerging field of cardio-oncology. In this review, we aimed to examine the bidirectional associations between cancer and hypertension including pharmacotherapy.
Modelling and solving of IGBT's transient analysis model based on the finite state machine
Authors: Hao Bin , Wu Yingzhe , Peng Cheng , Tang Xinling , Zhao Zhibin
Published: July 2021

To accurately obtain the switching characteristics of insulated gate bipolar transistors (IGBT), this paper proposes an IGBT's transient analysis model (TAM) based on the finite state machine (FSM). Firstly, the IGBT switching process in the basic converter unit is segmented in the time domain, and the circuit equations among the variables are obtained based on Kirchhoff's law. Then, the switching mechanism and parameters of the IGBT are decoupled based on time segmentation, and clarifying state equations and the transition events for each stage. Subsequently, all the stages and events are modeled in an FSM, thus establishing the IGBT's TAM, and it was realized the Stateflow toolbox of Matlab/Simulink. Finally, some experiments were performed on IGBTs with different current and voltage. The results show that the TAM can accurately describe the switching characteristics of IGBT and is suitable for different voltage and current levels.
Joint primary frequency regulation strategy for asynchronous power grids connected by a VSC‐MTDC system
Authors: Wang Guoteng , Zhang Zheren , Xu Zheng
Published: July 2021

Asynchronous interconnection will reduce the inertia of each grid, and it is difficult for a small inertia grid to maintain frequency stability under the fluctuation of new energy or load. In order to improve the frequency stability of asynchronous power grids connected by a voltage source converters based multi‐terminal direct current (VSC‐MTDC) system, a joint primary frequency regulation (JPFR) strategy is proposed in this paper. The main principle of the proposed JPFR strategy is firstly to formulate frequency regulation protocols (FRPs) between asynchronous power grids. Next, an improved analytical steady‐state model of the VSC‐MTDC system is adopted. The improved model can calculate the power reference of each VSC according to the FRP, avoiding the impact on the grid not participating in the protocol. Then, based on the sequential search method, the results of the improved model are modified to prevent overload. Finally, simulations of a four‐terminal VSC‐MTDC system are carried out for validating the proposed JPFR strategy.
Seismic performance of frame‐bent structures subjected to near‐fault ground motions
Authors: Zhang Shuyun , Huang Lei , Wang Gang , Ma Yousufu
Published: July 2021

Reinforced concrete frame‐bent structures are one of the structural forms commonly used in industrial factory buildings. In order to study the seismic behaviour of frame‐bent structures located near fault areas, eight pulse‐like, eight non‐pulse near‐fault motions and eight far‐fault ground motions have been selected in this paper. The finite element model of a reinforced concrete frame‐bent structure was established to study seismic responses to near‐fault and far‐field ground motions. Numerical analysis results indicate that the maximum base shear of the structure under the action of near‐fault ground motion was 5.10 times that of far‐fault and 1.47 times that of non‐pulsed near‐fault ground motion; the maximum story drift angle under pulse‐like near‐fault ground motion was 3.8 times that of non‐pulse and 19.7 times that of far‐fault ground motion. Therefore, engineering designers should pay more attention to the seismic performance of frame‐bent structures under the action of near‐fault ground vibration.
Überprüfung der Kompetenzen von Notfallsanitätern – Umfragestudie zu
Umsetzung und Rahmenbedingungen durch Ärztliche Leiter
Rettungsdienst
Authors: Ostmeier Stefan , Eismann Hendrik , Hofmann Thomas , Flentje Markus
Published: July 2021

Hintergrund Eine Kompetenzüberprüfung von Notfallsanitätern (NFS) ist
durch die Ärztlichen Leiter Rettungsdienst (ÄLRD) empfohlen. Die Umsetzung
erfolgt individuell im Rettungsdienstbereich. Ziel der Studie ist die
Beschreibung der aktuellen Situation als Diskussionsbeitrag für
Weiterentwicklungen.

Methode In der Zeit von Sept. 2019 bis Mai 2020 wurden die ÄLRD zu ihren
verfügbaren Ressourcen, der Art der Kompetenzüberprüfung, der Konsequenzen und
Bewertung der eigenen Arbeit befragt.

Ergebnisse Siebzig ÄLRD sind im Mittel für 311 NFS zuständig. Die
Überprüfung wird in 87,1% von Praxisanleitern (PA) unterstützt. Am häufigsten
werden Fallszenarien eingesetzt. 10% überprüfen nicht. Die ÄLRD bewerten ihre
eigene Arbeit mit der Schulnote befriedigend und nennen mangelnde Ressourcen als
Haupthinderungsgrund. Bei Nichtbestehen werden Wiederholungsprüfungen angeboten
und der Einsatz als Transportführer ausgesetzt.

Schlussfolgerung In vielen Bereichen findet eine Überprüfung nach Vorgaben
des Pyramidenprozesses II statt. Einzelne Bereiche überprüfen die Kompetenz
nicht oder wenden nichtgeeignete Prüfungsformate an. Die Praxisanleiter leisten
einen wichtigen Beitrag. Übergreifende Konzepte mit Transparenz und Qualität
sind weiterzuentwickeln, um Konsequenzen aus Überprüfungen zu rechtfertigen.
Bundesweite Konzepte können ÄLRD entlasten und die Einsatzflexibilität der
Mitarbeiter erhöhen.
Subjektives Wohlbefinden und Arbeitsfähigkeit von Krankenhauspersonal nach SARS-CoV-2-Immunisierung mit dem mRNS-Impfstoff BNT162b2 – Ergebnisse einer anonymen Umfrage
Authors: Kalbhenn Johannes , Hammer Thorsten , Hug Martin , Dürschmied Daniel , Wenz Frederik , Steinmann Daniel
Published: July 2021

Einleitung Seit dem 27.12.2020 wurden in Deutschland unter anderem MitarbeiterInnen des Gesundheitssystems mit dem Vakzin BNT162b2 gegen das SARS-Coronavirus-2 geimpft. Erste Beobachtungen zeigten, dass es insbesondere bei jüngeren Geimpften zu Nebenwirkungen kommen kann. In dieser Studie wurde am Beispiel von KlinikmitarbeiterInnen das selbstempfundene Wohlbefinden nach der jeweils ersten und zweiten Dosis des Impfstoffes untersucht.

Methoden Anonymisierter Online-Fragebogen, einmalig ausfüllbar durch alle MitarbeiterInnen nach Erhalt der zweiten Dosis von BNT162b2. Die Ausprägung von Nebenwirkungen wurde über eine ordinale numerische Rating-Skala mit Werten zwischen 0 und 10 abgefragt. Weitere wesentliche Datenpunkte waren Alter, Geschlecht und Berufsgruppe. Die Arbeitsfähigkeit in den Folgetagen der Injektionen wurde ebenfalls durch Selbstangabe erhoben.

Ergebnisse Es wurden Daten von 555 Befragten ausgewertet. Das mittlere Alter lag bei 40,25 Jahren (Standardabweichung 12,35). 56 % der Befragten waren weiblich, 44,3 % gehörten zum ärztlichen, 42,9 % zum pflegerischen Dienst und 12,8 % waren anderen Berufsgruppen mit COVID-19-Patientenkontakt zuzuordnen. Etwa 2 % aller Mitarbeiter verspürten überhaupt keine Nebenwirkungen. Häufigste Nebenwirkung waren Schmerzen an der Injektionsstelle. In absteigender Häufigkeit folgten Müdigkeit, Kopfschmerzen und Myalgien. Nach der ersten Dosis gaben 3 Viertel der Befragten an, die Impfung insgesamt gut vertragen zu haben, nach der zweiten Dosis war es nur noch die Hälfte. Nach der ersten Dosis fühlten sich über 90 % der Befragten am Folgetag wieder arbeitsfähig, nach der zweiten Dosis gab ein Drittel an, erst am zweiten Tag wieder arbeitsfähig gewesen zu sein. 2,2 % aller MitarbeiterInnen mussten sich nach der ersten, 19,5 % nach der zweiten Dosis für mindestens einen Tag arbeitsunfähig melden.

Schlussfolgerung Die Impfung mit BNT162b2 führte – insbesondere nach der zweiten Dosis – häufig zu Nebenwirkungen. Diese hatten in 19 % der Befragten eine Krankmeldung nach der zweiten Dosis zur Folge. Dennoch würden sich 95 % aller Befragten wieder für eine Coronavirus-Impfung entscheiden.
The Synthesis of Five-Membered N-Heterocycles by Cycloaddition of Nitroalkenes with (In)Organic Azides and Other 1,3-Dipoles
Authors: Pookkandam Parambil Shandev , Pulikkal Veettil Santhini , Dehaen Wim
Published: July 2021

Cycloaddition reactions have emerged as rapid and powerful methods for constructing heterocycles and carbocycles. [3+2] Cyclo­additions of nitroalkenes with various 1,3-dipoles have been an interesting research area for many organic chemists. This review outlines the synthesis of N-substituted and NH-1,2,3-triazoles along with other five-membered N-heterocycles through cycloaddition reactions of nitro­alkenes.

1 Introduction

2 Synthesis of 1,2,3-Triazoles

2.1 Synthesis of NH-1,2,3-Triazoles

2.2 Synthesis of N-Substituted 1,2,3-Triazoles

3 Synthesis of Pyrrolidines and Pyrroles

4 Synthesis of Pyrazoles

5 Conclusion
Management of Obesity and Nonalcoholic Fatty Liver Disease: A Literature Review
Authors: Hashem Anas , Khalouf Amani , Acosta Andres
Published: July 2021

With the recent urbanization and globalization, the adult obesity rate has been increasing, which was paralleled with a dramatic surge in the incidence and prevalence of nonalcoholic fatty liver disease (NAFLD). NAFLD poses a growing threat to human health as it represents the most common cause of chronic liver disease in developed countries. It encompasses a wide spectrum of conditions starting from a build-up of fat in hepatocytes (steatosis), to developing inflammation (steatohepatitis), and reaching up to cirrhosis. It is also associated with higher rates of cardiovascular mortalities. Therefore, proper timely treatment is essential and weight loss remains the cornerstone in the treatment of obesity-related liver diseases. When diet, exercise, and lifestyle changes are not successful, the current recommendation for weight loss includes antiobesity medications and bariatric endoscopic and surgical interventions. These interventions have shown to result in significant weight loss and improve liver steatosis and fibrosis. In the current literature review, we highlight the expected outcomes and side effects of the currently existing options to have a weight-centric NAFLD approach.
Clostridioides difficile Diarrhea: An Emerging Problem in a South Indian Tertiary Care Hospital
Authors: Kannambath Rachana , Biswas Rakhi , Mandal Jharna , Vinod Kolar V. , Dubashi Biswajit , Parameswaran Narayanan
Published: July 2021

Context Clostridioides difficile infection (CDI) is one of the most common infectious causes of hospital-acquired diarrhea. The actual burden of the disease is underestimated in India due to inadequate diagnostic methods and limited studies conducted.

Aims The aim of this study was to determine the burden and risk factors of CDI among patients with hospital-acquired diarrhea.

Methods and Materials Stool specimen of patients (age > 1 year) with hospital-acquired diarrhea were screened for glutamate dehydrogenase antigen and toxin using an enzyme immunoassay. If both antigen and toxin were present, it was reported as positive for toxigenic CDI. Samples positive for antigen and negative for toxin were further tested with Cepheid GeneXpert assay for detecting the toxin producing gene.

Results Of 75 patients (mean age 36.07 ± 20.79, 64% males), 14 (18.67%) patients were positive for toxigenic Clostridioides difficile (C. difficile) and 3 (4%) patients were nontoxigenic C. difficile. Addition of GeneXpert to the testing algorithm increased the yield of toxin detection in 5/14 patients who were negative by toxin assay. On analysis of risk factors, prolonged hospital stay was found to have significant association (p-value = 0.022). Patients with factors like intensive care unit stay, presence of diabetes mellitus as a comorbidity, and exposure to antibiotics like carbapenems and glycopeptides have been found to have a higher prevalence of CDI.

Conclusions The prevalence of CDI in our population was 18.67% and the major risk factor associated was prolonged hospital stay. The addition of GeneXpert for the detection of toxin gene increased the yield from 12 to 18.68%.
Stabilization of Talocalcaneal Luxation with a Dorsal 1.0 mm Compression Plate in Four Cats
Authors: Smith Matthew , Macdonald Nicholas
Published: July 2021

The objective of this case series was to report the surgical technique, complications, and long-term outcome of feline talocalcaneal luxation stabilized with a dorsally applied two-hole, 1.0 mm compression plate. It is a retrospective study of four cats that underwent surgical stabilization of talocalcaneal luxation with a dorsally applied two-hole, 1.0 mm compression plate between 2013 and 2019. Medical history and diagnostic imaging (radiographs ± computed tomography scans) were reviewed. The owners of three of the four cats were contacted with a follow-up questionnaire based on the Feline Musculoskeletal Pain Index to assess long-term outcome. No intraoperative or postoperative complications were encountered. All three owner questionnaires were returned and Feline Musculoskeletal Pain Index scores of 0, 1, and 4 were recorded out of a maximum score of 83 (normal cat range is −18 to 4; cats with degenerative joint disease range from 11 to 66). Quality of life was rated by the owners as excellent (⅔) or good (⅓). All cats returned to full activity. Stabilization of feline talocalcaneal luxation with a dorsally applied two-hole, 1.0 mm compression plate was technically straightforward, easily accessible, and a relatively low-cost treatment option which carries a low risk of complications and an excellent prognosis.
NESTROFT—A Cost-Effective Mass Screening Tool for the Detection of β-Thalassemia Carrier Status in Anemic Pregnant Women: A Step Toward Reducing the National Disease Burden
Authors: Gosavi Manasi , Chavan Ramesh , Bellad M. B.
Published: July 2021

Introduction β-Thalassemias are inherited hemoglobinopathies commonly encountered in practice. With chances of a promising cure being rare, the prevention of births with this disorder should assume priority, especially in low-resource countries. This can be achieved by the implementation of a mass screening program that is reliable and, at the same time, cost-effective.

Objectives This study focuses on the utility of Naked Eye Single Tube Red Cell Osmotic Fragility Test (NESTROFT) as a mass screening tool to detect thalassemia carriers. Hematological parameters that may predict carrier status were also evaluated.

Materials and Methods Hemoglobin estimation was performed on all consented pregnant women. If the patient was found to have hemoglobin < 11 g/dL, the blood sample was subjected to other routine hematological tests along with peripheral smear examination. NESTROFT was performed using 0.36% saline solution. Confirmation was done using high-performance liquid chromatography (HPLC).

Statistical Analysis Data obtained were tabulated using version 21 of the Statistical Package for Social Sciences. Means, standard deviations, and percentages were used to describe the sample. Chi-square test and Students’ t test were used to identify differences between the groups.

Results Of 441 pregnant women enrolled, 206 were found to be anemic. Nineteen (9.2%) of the anemic pregnant women were detected to be carriers of hemoglobinopathies. Among the hematological parameters, mean red blood cell count and reticulocyte count were higher, while mean corpuscular hemoglobin concentration was lower in carriers. Also, carriers were more likely to present with microcytic hypochromic anemia. NESTROFT showed a sensitivity of 84.21%, specificity of 96.25%, a positive predictive value of 69.56%, and a negative predictive value of 98.36%. A false-positive result was seen in 3.74% of the tests, while a false negative result was seen in 15.78% of the tests.

Conclusions NESTROFT (0.36%) can be used as a simple and cost-effective mass screening tool for the detection of carrier status. This should be followed by confirmation using HPLC or hemoglobin electrophoresis.
1.3 Modelling Radicals and Their Reactivities
Authors: Derat E. , Braïda B.
Published: July 2021

In this chapter, the application of computational quantum mechanical methods to the understanding of radical reactions is introduced. For radical reactions, access to electronic configurations through quantum chemical calculations allows rationalization of unusual reactivities. Using the valence bond approach, the nature of bonding in three-electron bonds can be characterized by large resonance interactions. Similarly, some simple reactions that are commonly believed to be radical-free, such as [3 + 2] cycloadditions, are in fact governed by a high-lying biradical intermediate that helps to stabilize the transition state. More complex radical and enzymatic reactions can also be modelled, as illustrated by the example of horseradish peroxidase. These case studies show that computational analysis can complement experimental investigations and fill in the blanks to enable a more complete understanding of radical reactions.
Attenuation of thermoacoustic combustion oscillations in a swirl-stabilized turbulent combustor
Authors: Kurosaka Takuya , Masuda Shinga , Gotoda Hiroshi
Published: July 2021

We experimentally study the attenuation behavior of thermoacoustic combustion oscillations using causality analysis, multiscale randomness analysis, and a complex network. We supply a steady air jet from the injector rim to suppress combustion oscillations. The directional coupling between pressure and heat release rate fluctuations is significantly weakened during the suppression of combustion oscillations. The loss of the primary hub in the turbulence network plays an important role in the degeneration of combustion oscillations.
Data-driven approach for noise reduction in pressure-sensitive paint data based on modal expansion and time-series data at optimally placed points
Authors: Inoue Tomoki , Matsuda Yu , Ikami Tsubasa , Nonomura Taku , Egami Yasuhiro , Nagai Hiroki
Published: July 2021

We propose a noise reduction method for unsteady pressure-sensitive paint (PSP) data based on modal expansion, the coefficients of which are determined from time-series data at optimally placed points. In this study, the proper orthogonal decomposition (POD) mode calculated from the time-series PSP data is used as a modal basis. Based on the POD modes, the points that effectively represent the features of the pressure distribution are optimally placed by the sensor optimization technique. Then, the time-dependent coefficient vector of the POD modes is determined by minimizing the difference between the time-series pressure data and the reconstructed pressure at the optimal points. Here, the coefficient vector is assumed to be a sparse vector. The advantage of the proposed method is a self-contained method, while existing methods use other data, such as pressure tap data for the reduction of the noise. As a demonstration, we applied the proposed method to the PSP data measuring the Kármán vortex street behind a square cylinder. The reconstructed pressure data agreed very well with the pressures independently measured by pressure transducers. This modal-based approach will be applicable not only to PSP data but other types of experimental data.
A space-fractional bidomain framework for cardiac electrophysiology: 1D alternans dynamics
Authors: Cusimano Nicole , Gerardo-Giorda Luca , Gizzi Alessio
Published: July 2021

Cardiac electrophysiology modeling deals with a complex network of excitable cells forming an intricate syncytium: the heart. The electrical activity of the heart shows recurrent spatial patterns of activation, known as cardiac alternans, featuring multiscale emerging behavior. On these grounds, we propose a novel mathematical formulation for cardiac electrophysiology modeling and simulation incorporating spatially non-local couplings within a physiological reaction–diffusion scenario. In particular, we formulate, a space-fractional electrophysiological framework, extending and generalizing similar works conducted for the monodomain model. We characterize one-dimensional excitation patterns by performing an extended numerical analysis encompassing a broad spectrum of space-fractional derivative powers and various intra- and extracellular conductivity combinations. Our numerical study demonstrates that (i) symmetric properties occur in the conductivity parameters’ space following the proposed theoretical framework, (ii) the degree of non-local coupling affects the onset and evolution of discordant alternans dynamics, and (iii) the theoretical framework fully recovers classical formulations and is amenable for parametric tuning relying on experimental conduction velocity and action potential morphology.
A general approach for calculating melt–solid impurity segregation coefficients based on thermodynamic integration
Authors: Luo Jinping , Cheng Yunjie , Zhou Chenyang , Sinno Talid , Liu Lijun
Published: July 2021

The equilibrium segregation of impurities at the melt–solid interface during silicon crystallization is a key factor in determining the impurity concentration and distribution in the crystal. Unfortunately, this property is difficult to measure experimentally due to the presence of complex transport physics in the melt. Here, using the Tersoff family of empirical potential models, we describe a thermodynamic integration framework for computing the interstitial oxygen and substitutional carbon segregation coefficients in silicon. Thermodynamic integration using an ideal gas reference state for the impurity atoms is shown to be an efficient and convenient pathway for evaluating impurity chemical potentials in both solid and liquid phases. We find that the segregation coefficient is captured well for substitutional carbon impurity while it is significantly underestimated for interstitial oxygen. The latter discrepancy is partially attributed to the qualitatively incorrect silicon solid-to-liquid density ratio predicted by the empirical interatomic potential.
Hyperdiffusion of dust particles in a turbulent tokamak plasma
Authors: Nespoli F. , Kaganovich I. D. , Autricque A. , Marandet Y. , Tamain P.
Published: July 2021

The effect of plasma turbulence on the trajectories of dust particles is investigated for the first time. The dynamics of dust particles is computed using the ad hoc developed Dust Injection Simulator code, using a 3D turbulent plasma background computed with the TOKAM3X code. As a result, the evolution of the particle trajectories is governed by the ion drag force, and the shape of the trajectory is set by the Stokes number St∝ad/n0, with ad the dust radius and n0 the density at the separatrix. The plasma turbulence is observed to scatter the dust particles, exhibiting a hyperdiffusive regime in all cases. The amplitude of the turbulent spread of the trajectories Δr2 is shown to depend on the ratio Ku/St, with Ku∝urms the Kubo number and urms the fluctuation level of the plasma flow. These results are compared with a simple analytical model, predicting Δr2∝(Ku/St)2t3, or Δr2∝(urmsn0/ad)2t3. As the dust is heated by the plasma fluxes, thermionic emission sets the dust charge, originally negative, to slightly positive values. This results in a substantial reduction of the ion drag force through the suppression of its Coulomb scattering component. The dust grain inertia is then no longer negligible and drives the transition from a hyperdiffusive regime toward a ballistic one.
Near-field radio-frequency imaging by spin-locking with a nitrogen-vacancy spin sensor
Authors: Nomura Shintaro , Kaida Koki , Watanabe Hideyuki , Kashiwaya Satoshi
Published: July 2021

We present results of near-field radio-frequency (RF) imaging at micrometer resolution using an ensemble of nitrogen-vacancy (NV) centers in diamond. The spatial resolution of RF imaging is set by the resolution of an optical microscope, which is markedly higher than the existing RF imaging methods. High sensitivity RF field detection is demonstrated through spin locking. SCROFULOUS composite pulse sequence is used for manipulation of the spins in the NV centers for reduced sensitivity to possible microwave pulse amplitude error in the field of view. We present procedures for acquiring an RF field image under spatially inhomogeneous microwave field distribution and demonstrate a near-field RF imaging of an RF field emitted from a photolithographically defined metal wire. The obtained RF field image indicates that the RF field intensity has maxima in the vicinity of the edges of the wire, in accord with a calculated result by a finite-difference time-domain method. Our method is expected to be applied in a broad variety of application areas, such as material characterizations, characterization of RF devices, and medical fields.
Quantitative modeling and experimental verification of Förster resonant energy transfer in upconversion nanoparticle biosensors
Authors: Das Ananda , Corbella Bagot Conrad , Rappeport Eric , Ba Tis Taleb , Park Wounjhang
Published: July 2021

Rare-earth-doped upconversion nanoparticles (UCNPs) have often been used in combination with fluorescent dyes for sensing applications. In these systems, sensing can be achieved through the modulation of Förster resonant energy transfer (FRET) between the dye and the UCNP. The effects of FRET in such cases are complex, as the extent to which FRET is experienced by the rare-earth ions is dependent on their position within the nanoparticle. Here, we develop an analytical model to accurately describe the effects of FRET for such a system. As a proof of principle, we verify our model by considering the case of a pH sensor comprised of fluorescein isothiocyanate and Tm3+-doped UCNPs. We extend our model to the case of core–shell UCNPs and discuss the design of an optimal FRET-based biosensor using UCNPs.
The density matrix via few dominant observables: The quantum interference in the isotope effect for atto-pumped N2
Authors: Komarova K. , Remacle F. , Levine R. D.
Published: July 2021

Atto- and sub-femto-photochemistry enables preparation of molecules in a coherent superposition of several electronic states. Recently [Ajay et al., Proc. Natl. Acad. Sci. U. S. A. 115, 5890–5895 (2018)], we examined an effect of the nuclear mass during the non-adiabatic transfer between strongly coupled Rydberg and valence electronic states in N2 excited by an ultrafast pulse. Here, we develop and analyze an algebraic description for the density matrix and its logarithm, the surprisal, in such a superposition of states with a focus on the essentially quantum effect of mass. This allows for the identification of a few observables that accurately characterize the density matrix of the system with several coupled electron-nuclear states. We compact the time evolution in terms of time-dependent coefficients of these observables. Using the few observables, we derive an analytical expression for the time-dependent surprisal. This provides a mass-dependent phase factor only in the observables off-diagonal in the electronic index. The isotope effect is shown to be explicitly driven by the shift in the equilibrium position of the valence state potential. It is analytically given as a time-dependent phase factor describing the interference in the overlap of the two wave packets on the coupled electronic states. This phase factorizes as a product of classical and quantal contributions.
Time-averaged mean squared displacement ratio test for Gaussian processes with unknown diffusion coefficient
Authors: Maraj Katarzyna , Szarek Dawid , Sikora Grzegorz , Wyłomańska Agnieszka
Published: July 2021

The time-averaged mean squared displacement (TAMSD) is one of the most common statistics used for the analysis of anomalous diffusion processes. Anomalous diffusion is manifested by non-linear (mostly power-law) characteristics of the process in contrast to normal diffusion where linear characteristics are expected. One can distinguish between sub- and super-diffusive processes. We consider Gaussian anomalous diffusion models and propose a new approach used for their testing. This approach is based on the TAMSD ratio statistic for different time lags. Similar to the TAMSD, this statistic exhibits a specific behavior in the anomalous diffusion regime. Through its structure, it is independent of the diffusion coefficient, which, in general, does not influence anomalous diffusion behavior. Thus, the TAMSD ratio-based approach does not require preliminary knowledge of the diffusion coefficient’s value, in contrast to the TAMSD-approach, where this value is crucial in the testing procedure. Based on the quadratic form representation of the TAMSD ratio, we calculate its main characteristics and propose a step-by-step testing procedure that can be applied for any Gaussian process. For the anomalous diffusion model used here, namely, the fractional Brownian motion, we demonstrate the effectiveness of the proposed methodology. We show that the new approach outperforms the TAMSD-based one, especially for small sample sizes. Finally, the methodology is applied to the real data from the financial market.
Water accelerates the hydrogen-bond dynamics and abates heterogeneity in deep eutectic solvent based on acetamide and lithium perchlorate
Authors: Srinivasan H. , Sharma V. K. , Mitra S.
Published: July 2021

Deep eutectic solvents (DESs) have become a prevalent and promising medium in various industrial applications. The addition of water to DESs has attracted a lot of attention as a scheme to modulate their functionalities and improve their physicochemical properties. In this work, we study the effects of water on an acetamide based DES by probing its microscopic structure and dynamics using classical molecular dynamics simulation. It is observed that, at low water content, acetamide still remains the dominant solvate in the first solvation shell of lithium ions, however, beyond 10 wt. %, it is replaced by water. The increase in the water content in the solvent accelerates the H-bond dynamics by drastically decreasing the lifetimes of acetamide–lithium H-bond complexes. Additionally, water–lithium H-bond complexes are also found to form, with systematically longer lifetimes in comparison to acetamide–lithium complexes. Consequently, the diffusivity and ionic conductivity of all the species in the DES are found to increase substantially. Non-Gaussianity parameters for translational motions of acetamide and water in the DES show a conspicuous decrease with addition of water in the system. The signature of jump-like reorientation of acetamide is observed in the DES by quantifying the deviation from rotational Brownian motion. However, a notable decrease in the deviation is observed with an increase in the water content in the DES. This study demonstrates the intricate connection between H-bond dynamics and various microscopic dynamical parameters in the DES, by investigating the modulation of the former with addition of water.
Temperature-dependent dynamic structure factors for liquid water inferred from inelastic neutron scattering measurements
Authors: Noguere G. , Scotta J. P. , Xu S. , Farhi E. , Ollivier J. , Calzavarra Y. , Rols S. , Koza M. , Marquez Damian J. I.
Published: July 2021

Temperature-dependent dynamic structure factors S(Q, ω) for liquid water have been calculated using a composite model, which is based on the decoupling approximation of the mean square displacement of the water molecules into diffusion and solid-like vibrational parts. The solid-like vibrational part Svib(Q, ω) is calculated with the phonon expansion method established in the framework of the incoherent Gaussian approximation. The diffusion part Sdiff(Q, ω) relies on the Egelstaff–Schofield translational diffusion model corrected for jump diffusions and rotational diffusions with the Singwi–Sjölander random model and Sears expansion, respectively. Systematics of the model parameters as a function of temperature were deduced from quasi-elastic neutron scattering data analysis reported in the literature and from molecular dynamics (MD) simulations relying on the TIP4P/2005f model. The resulting S(Q, ω) values are confronted by means of Monte Carlo simulations to inelastic neutron scattering data measured with IN4, IN5, and IN6 time-of-flight spectrometers of the Institut Laue-Langevin (ILL) (Grenoble, France). A modest range of temperatures (283–494 K) has been investigated with neutron wavelengths corresponding to incident neutron energies ranging from 0.57 to 67.6 meV. The neutron-weighted multiphonon spectra deduced from the ILL data indicate a slight overestimation by the MD simulations of the frequency shift and broadening of the librational band. The descriptive power of the composite model was suited for improving the comparison to experiments via Bayesian updating of prior model parameters inferred from MD simulations. The reported posterior temperature-dependent densities of state of hydrogen in H2O would represent valuable insights for studying the collective coupling interactions in the water molecule between the inter- and intramolecular degrees of freedom.
The wobbling motion of single and two inline bubbles rising in quiescent liquid
Authors: Cao Yuanwei , Macián-Juan Rafael
Published: July 2021

The wobbling motions of single and two inline bubbles rising in quiescent liquid are investigated via three-dimensional simulations using the volume of fluid method. First, we simulate an 8 mm air bubble rising in quiescent water, yielding the wobbling motion. The bubble wobbling has two roles: (1) the excessive curvature speeds up the separation of the boundary layer and (2) the velocity peaks (high Reynolds number) result in the formation of asymmetrical vortices. The oscillation frequencies (6 Hz, St = 0.22) of the bubble movement, the vorticity accumulated on the bubble surface, the lift force and viscous force are the same while the oscillation frequency of the aspect ratio is twice that of the bubble movement. The volume-averaged liquid velocity presents a linear increase with the bubble rise while the kinetic energy displays a quadratic increase. Finally, two bubbles rising inline are investigated with different initial distances. The central breakup of the trailing bubble is observed at a short distance of 2d (d is the bubble diameter). For a longer distance of 6d, the wake of the leading bubble results in the lateral motion of the trailing bubble, depending on the position of the trailing bubble in the wake and the intensity of the vortices it encounters.
Electronic spectroscopy of the A1̃2A′′/A2̃2A′−X̃2A′ transitions of jet-cooled calcium ethoxide radicals: Vibronic structure of alkaline earth monoalkoxide radicals of C
s symmetry
Authors: Paul Anam C. , Sharma Ketan , Telfah Hamzeh , Miller Terry A. , Liu Jinjun
Published: July 2021

Laser-induced fluorescence/dispersed fluorescence (LIF/DF) and cavity ring-down spectra of the A1̃2A′′/A2̃2A′−X̃2A′ electronic transition of the calcium ethoxide (CaOC2H5) radical have been obtained under jet-cooled conditions. An essentially constant Ã2−Ã1 energy separation for different vibronic levels is observed in the LIF spectrum, which is attributed to both the spin–orbit (SO) interaction and non-relativistic effects. Electronic transition energies, vibrational frequencies, and spin–vibrational eigenfunctions calculated using the coupled-cluster method, along with results from previous complete active space self-consistent field calculations, have been used to predict the vibronic energy level structure and simulate the recorded LIF/DF spectra. Although the vibrational frequencies and Franck–Condon (FC) factors calculated under the Born–Oppenheimer approximation and the harmonic oscillator approximation reproduce the dominant spectral features well, the inclusion of the pseudo-Jahn–Teller (pJT) and SO interactions, especially those between the A1̃2A″/A2̃2A′ and the B̃2A′ states, induces additional vibronic transitions and significantly improves the accuracy of the spectral simulations. Notably, the spin–vibronic interactions couple vibronic levels and alter transition intensities. The calculated FC matrix for the A1̃2A′′/A2̃2A′−X̃2A′ transition contains a number of off-diagonal matrix elements that connect the vibrational ground levels to the levels of the ν8 (CO stretch), ν11 (OCC bending), ν12 (CaO stretch), ν13 (in-plane CaOC bending), and ν21 (out-of-plane CaOC bending) modes, which are used for vibrational assignments. Transitions to the ν21(a″) levels are allowed due to the pJT effect. Furthermore, when LIF transitions to the Ã-state levels of the CaOC-bending modes, ν13 and ν21, are pumped, A1̃2A′′/A2̃2A′→X̃2A′ transitions to the combination levels of these two modes with the ν8, ν11, and ν12 modes are also observed in the DF spectra due to the Duschinsky mixing. Implications of the present spectroscopic investigation to laser cooling of asymmetric-top molecules are discussed.
Factors that influence hydrogen binding at metal-atop sites
Authors: Zheng Huiling , Li Hao , Luo Long , Zhao Zhen , Henkelman Graeme
Published: July 2021

The d-band model has proven to be effective for understanding trends in the chemisorption of various adsorbates on transition metal surfaces. However, hydrogen adsorption at the atop site of transition metals and their bimetallic alloy surfaces do not always correlate well with the d-band center of the adsorption site. Additionally, the d-band model cannot explain the disappearance of the local minima for H adsorption at the hollow site on the potential energy surface of 5d single-atom element doped Au and Ag(111) surfaces. Here, we use a simple model with factors, including the d-band center, filling of the d-band, renormalized adsorbate states, coupling matrix elements, and surface–adsorbate bond lengths, to correlate with the density functional theory calculated H binding energies on both mono- and bimetallic (111) surfaces. Our results suggest that H adsorption at metal-atop sites is determined by all these factors, not only by the d-band center. The strong adsorption of H at the atop sites of 5d metal surfaces can be explained by their lower repulsive contribution.
Large age shifts in HIV-1 incidence patterns in KwaZulu-Natal, South Africa
Authors: Akullian Adam , Vandormael Alain , Miller Joel C. , Bershteyn Anna , Wenger Edward , Cuadros Diego , Gareta Dickman , Bärnighausen Till , Herbst Kobus , Tanser Frank
Published: July 2021

Significance

HIV incidence has recently been in decline across some of the most intense epidemics in sub-Saharan Africa due to the scale-up of prevention and transmission-blocking treatments. Understanding whether declines in incidence are being felt equally across age and gender can help prioritize demographic groups where more effort is needed to lower transmission. We found that HIV incidence has declined disproportionately in the youngest men and women in a population with the highest HIV prevalence in the world. Shifts in the age distribution of risk may be the consequence of aging prevalence, prioritized prevention to younger individuals, and delays in age at infection from reduced overall force of infection. Our results highlight the need to expand age targets for HIV prevention.
Temporal compartmentalization of viral infection in bacterial cells
Authors: Labarde Audrey , Jakutyte Lina , Billaudeau Cyrille , Fauler Beatrix , López-Sanz Maria , Ponien Prishila , Jacquet Eric , Mielke Thorsten , Ayora Silvia , Carballido-López Rut , Tavares Paulo
Published: July 2021

Significance

Virus lytic infection disrupts host cell homeostasis and takes over the cell space for virus multiplication. Viral-induced reorganization of prokaryotic cells must meet the challenge to restructure the cytoplasm open space of a small-sized cell. We discovered that the bacterial siphovirus SPP1 builds two types of independent compartments in the host cytoplasm to confine viral DNA enzymatic reactions and to store viral particles. This spatial partition responds to the requirements for exponential replication of SPP1 genomes and for the assembly of hundreds of viral particles. Its similarities to remodeling of the cell nucleus by herpesviruses led to the hypothesis that ancestral strategies used by viruses to invade the cell space were conserved to infect hosts of different domains of life.