bluuebunny/crossref_metadata_2025 huggingface dataset:
A more sustainable isothiocyanate synthesis by amine catalyzed sulfurization of isocyanides with elemental sulfur
Authors: Nickisch R. , Conen P. , Gabrielsen S. M. , Meier M. A. R.
Published: January 2021

Isothiocyanates were snythesized in a more sustainable manner by sulfurization of isocyanides with elemental sulfur using catalytic amounts of DBU (down to 2 mol%).
Hierarchical dynamics in allostery following ATP hydrolysis monitored by single molecule FRET measurements and MD simulations
Authors: Wolf Steffen , Sohmen Benedikt , Hellenkamp Björn , Thurn Johann , Stock Gerhard , Hugel Thorsten
Published: January 2021

We report on a study that combines advanced fluorescence methods with molecular dynamics simulations to cover timescales from nanoseconds to milliseconds for a large protein, the chaperone Hsp90.
Iridium-catalyzed enantioselective olefinic C(sp2)–H allylic alkylation
Authors: Sarkar Rahul , Mukherjee Santanu
Published: January 2021

The first iridium-catalyzed enantioselective allylic alkylation of an olefinic C(sp2)–H bond – that of an α,β-unsaturated carbonyl compound, is developed in cooperation with Lewis base catalysis.
An expanding bacterial colony forms a depletion zone with growing droplets
Authors: Ma Hui , Bell Jordan , Chen Weijie , Mani Sridhar , Tang Jay X.
Published: January 2021

Bacterial droplets formed in a depletion zone following its spread over a large agar plate.
Microrheology of semiflexible filament solutions based on relaxation simulations
Authors: Duarte L. K. R. , Teixeira A. V. N. C. , Rizzi L. G.
Published: January 2021

We present an efficient computational methodology to obtain the viscoelastic response of dilute solutions of semiflexible filaments.
Understanding extreme fast charge limitations in carbonate mixtures
Authors: Mallarapu Anudeep , Bharadwaj Vivek S. , Santhanagopalan Shriram
Published: January 2021

Impact of local solvation structures on transport of Li+ under extreme fast charging.
Journal of Materials Chemistry A and Materials Advances Editor’s choice web collection: “Machine learning for materials innovation”
Authors: Zhou Zhen
Published: January 2021

Zhen Zhou introduces a Journal of Materials Chemistry/Materials Advances Editor’s choice web collection on machine learning for materials innovation (https://rsc.li/MachineLearning).
Intermolecular locking design of red thermally activated delayed fluorescence molecules for high-performance solution-processed organic light-emitting diodes
Authors: Jin Jibiao , Wang Wuji , Xue Peiran , Yang Qingqing , Jiang He , Tao Ye , Zheng Chao , Xie Guohua , Huang Wei , Chen Runfeng
Published: January 2021

An intermolecular locking strategy was proposed to improve both the solution processibility and photoluminescence efficiency of red TADF emitters for solution-processed OLEDs with an EQE up to 8.2% and an efficiency roll-off of 9.0% at 1000 cd m−2.
Concentration-dependent supramolecular self-assembly of A1/A2-asymmetric-difunctionalized pillar[5]arene
Authors: Al-Azemi Talal F. , Vinodh Mickey
Published: January 2021

Concentration-dependent supramolecular self-assembly of A1/A2-asymmetric-difunctionalized pillar[5]arene was synthesized by co-cyclization strategy. This approach enables wide range of structural manipulations to regulate the supramolecular assembly.
Structural insights into DNA double-strand break signaling
Authors: Panigrahi Rashmi , Glover J. N. Mark
Published: January 2021

Genomic integrity is most threatened by double-strand breaks, which, if left unrepaired, lead to carcinogenesis or cell death. The cell generates a network of protein–protein signaling interactions that emanate from the DNA damage which are now recognized as a rich basis for anti-cancer therapy development. Deciphering the structures of signaling proteins has been an uphill task owing to their large size and complex domain organization. Recent advances in mammalian protein expression/purification and cryo-EM-based structure determination have led to significant progress in our understanding of these large multidomain proteins. This review is an overview of the structural principles that underlie some of the key signaling proteins that function at the double-strand break site. We also discuss some plausible ideas that could be considered for future structural approaches to visualize and build a more complete understanding of protein dynamics at the break site.
Elaboration of wide bandgap CIGS on silicon by electrodeposition of stacked metal precursors and sulfur annealing for tandem solar cell applications
Authors: Crossay Alexandre , Cammilleri Davide , Thomere Angelica , Zerbo Bienlo , Rebai Amelle , Barreau Nicolas , Lincot Daniel
Published: January 2021

A method was developed for the electrodeposition of Cu-In-Ga precursor layers to elaborate Cu(In,Ga)(S,Se)2 (CIGS) thin films on silicon substrates for future application as silicon/wide-gap CIGS tandem solar cells. An underlayer of Ag was first deposited on silicon substrates to ensure a good adhesion of the electrodeposited stack and to serve as cathode during the deposition process. Cu, In and Ga layers were then sequentially electrodeposited. Ag-Cu-In-Ga precursor layers were finally subjected to elemental sulfur annealing at 600 °C. Formation of compact and adherent AgCIGS is observed. X ray diffraction and photoluminescence analyses confirm the formation of wide-gap CIGS of about 1.6 eV, with a spontaneous gallium grading over the depth of the sample leading to the formation of a bi-layer structure with a gallium rich layer at the interface with silicon.
Prediction of Financial Health of Business Entities of Selected Sector Using Balance Analysis II. by Rudolf Doucha and Verification of Its Predictive Ability through ROC
Authors: Karpac Dusan , Bartosova Viera
Published: January 2021

Forecasting business failure is a worldwide known term, in a global notion, and there is a lot of prediction models constructed to compute financial health of a company and, by that, state whether a company inclines to financial boom or bankruptcy. A healthy financial management of a business entity is very important for the proper operation of the business, and it is therefore very important to know how to assess financial health and to anticipate possible problems that will be easier to eliminate in advance. Globalized prediction models compute financial health of companies, but the vast majority of models predicting business failure are constructed solely for the conditions of a particular country or even just for a specific sector of a national economy. Predictive models can indicate whether an entity tends to prosper or bankruptcy, and so we can assess the financial health of the business. This paper provides a description of the balance analysis II. by Rudolf Doucha, discusses its application to a sample of 266 Slovak subjects and points to its prediction in the given field. The verification of the ability to forecast bankruptcy or financial stability has been evaluated through ROC analysis.
Benefit’s Portfolio in a Company in Connection to the Generation of Managerial Applicants
Authors: Jančíková Kateřina , Milichovský František
Published: January 2021

The topic of remuneration of executive managers (included CEO) is considered such a key factor of personal management (PM). The issue of remuneration of high-ranking managers is a key area of personnel management and corporate governance. This is still a much-discussed topic, which seeks to answer the most important question: How to set management rules in companies so that all stakeholders behave effectively? It is high-ranking managers who are a specific group in which the creation of a remuneration contract must ensure the optimal connection of their performance with measurable indicators of the company. The consequences of their decisions can be clear for up to several years, so setting optimal benchmarks is more than important. The main aim of the research paper was to find a dependence between the type of respondent generation and the sought-after benefits in the managerial position. The hypothesis was defined as follows: the type of respondent generation influences the choice of benefit. IBM SPSS Statistics 25 was used to process and evaluate the data obtained from the structured questionnaire survey. The mathematical-statistical methods used to verify the dependence between selected variables were used the Chi-square test of independence of two variables.
Comparison of Selected Subjects of the Non-profit Sector in the Conditions of the Slovak Republic
Authors: Rosnerova Zuzana , Hraskova Dagmar
Published: January 2021

Non-profit organizations are a specific type of entities in the national economy that significantly helps to improve the living standards of the country’s population. The article focuses on the financial performance of entities in the non-profit sector of the Slovak Republic depending on the financial instrument of tax allocation, taking into account the time factor during which the entities operate in the non-profit sector. The aim of the article is to analyse the financial performance of non-profit organizations providing services of general interest and foundations with the subsequent specification of the results of the issue. We work with the hypothesis that in terms of financial performance, foundations will perform better compared to non-profit organizations. Segmentation, comparison and descriptive methods were used in the solved issue. Only in one of the analysed groups did we come to the result that the non-profit organization was able to obtain more funds than the foundation through the tax allocation tool in 2019. In the case of the other groups analysed, foundations were more financially efficient, whose performance significantly exceeded that of non-profit organizations. In terms of market life, based on the analysis, the most efficient organizations were organizations with a market life of 1-5 years and with a longer market life, their financial performance decreased. In the case of foundations, we found that the highest performance is achieved by foundations with a market existence of 15 - 20 years. We can therefore state that the established hypothesis was only partially confirmed, although in most cases foundations were more financially efficient.
Subjective evaluation of socio-economic situation of residents of the South Bohemian Region and factors impacting it
Authors: Kajanova Alena , Urban David
Published: January 2021

In our entry we focus on subjective evaluation of the socio-economic situation of residents of the South Bohemian Region. We explore and describe factors as well as contexts contributing to such subjective evaluations. The research was conducted via a survey, which made use of a self-designed questionnaire consisting of primarily closed scale questions focusing on areas including evaluating the socio-economic situation, the ability to manage own income. The sample consisted of 700 questionnaires.

The results of the research show that 43.4% of respondents have average income management skills and that the ability to manage income is statistically independent from age, education level, or sex of the respondent. Employment also does not statistically influence the ability. As part of subjective evaluation of poverty/wealth, the respondents feel to be middle class (29.1%), the extremes were selected seldomly. Only one percent evaluated their situation as poverty; 0.1% saw perceived themselves as wealthy.
Determining business value according to FCFE
Authors: Rowland Zuzana , Stanek Tomas
Published: January 2021

The large number of joint stock companies causes that investors strive for better awareness and information in the stock area. The objective of the contribution is to apply the method of discounted FCFE in the valuation of a specific company and to determine the parameters for the model application in practice. The data for the analysis are obtained from the database of Kofola ČeskoSlovensko a.s. The data are taken from the published annual reports for the years 2018 and 2019. First, a financial plan for a period of stability was created. Subsequently, the discount value of the company was calculated using the FCFE model. Finally, the calculation of the company value in the continuation phase was calculated. To achieve the research goal, the individual FCFE need to be discounted by the value of equity using the CAMP model. In conclusion, it can be assumed that the discount rate will remain stable and the prediction of the growth rate will not change. If there are no fundamental changes in the company e.g. in terms of dividend payment, investment activities, or changes in the working capital, it can be assumed that the value of the company should be stabilized until 2021.
Evaluation des Modellprojektes „Rezept für Bewegung“ in Baden-Württemberg mittels explorativer qualitativer Befragung
Authors: Emerich Sigrid , Preiser Christine , Rieger Monika A
Published: January 2021

Ziel der Studie Bewegung hat auf die Gesundheit einen positiven Effekt, der bereits in vielen Studien bewiesen wurde. Bei der Unterstützung der PatientInnen hin zu mehr Bewegung haben ÄrztInnen eine besondere Rolle. Vor diesem Hintergrund wurde 2009 das Modellprojekt „Rezept für Bewegung“ (RfB) in Deutschland ins Leben gerufen. Hierbei können ÄrztInnen ihren PatientInnen ein tatsächliches Rezept für Bewegung ausstellen. In Baden-Württemberg wurde dieses Angebot von 2015 bis 2016 in 4 Modellregionen erprobt. Ziel der vorliegenden Studie war es, nach dem Ende der Erprobung die Verwendung des RfB durch ÄrztInnen in Baden-Württemberg zu evaluieren.

Methodik Die an dem Programm teilnehmenden ÄrztInnen wurden qualitativ befragt. Die Befragung wurde anhand eines strukturierten Interviewleitfadens telefonisch durchgeführt.

Ergebnisse Die qualitative Befragung zeigte eine positive Einstellung der ÄrztInnen gegenüber dem RfB. Als hemmende Faktoren für die Ausstellung des RfB wurden fehlende örtliche Angebote und die fehlende direkte Kostenübernahme der Krankenkasse für die empfohlenen Bewegungsangebote angegeben. Weitere Einflussgrößen stellten die Eigenmotivation der PatientInnen sowie die antizipierte Wahrscheinlichkeit der Umsetzung der Bewegungsempfehlung dar.

Schlussfolgerung Durch die vorliegende qualitative Erhebung konnten nicht nur Hemmnisse bei der Ausstellung des RfB durch ÄrztInnen und der Umsetzung der Bewegungsempfehlungen durch die PatientInnen, sondern auch förderliche Faktoren mit Blick auf die künftige Verwendung des RfB außerhalb des Modellvorhabens dokumentiert werden.
HPLC-UV, Metabarcoding and Genome Skims of Botanical Dietary Supplements: A Case Study in Echinacea
Authors: Handy Sara M. , Pawar Rahul S. , Ottesen Andrea R. , Ramachandran Padmini , Sagi Satyanarayanaraju , Zhang Ning , Hsu Erica , Erickson David L.
Published: January 2021

The use of DNA-based methods to authenticate botanical dietary supplements has been vigorously debated for a variety of reasons. More comparisons of DNA-based and chemical methods are needed, and concordant evaluation of orthogonal approaches on the same products will provide data to better understand the strengths and weaknesses of both approaches. The overall application of DNA-based methods is already firmly integrated into a wide array of continually modernizing stand alone and complementary authentication protocols. Recently, the use of full-length chloroplast genome sequences provided enhanced discriminatory capacity for closely related species of Echinacea compared to traditional DNA barcoding approaches (matK and rbcL). Here, two next-generation sequencing approaches were used: (1) genome skimming and (2) PCR amplicon (metabarcoding). The two genetic approaches were then combined with HPLC-UV to evaluate 20 commercially available dietary
supplements of Echinacea representing “finished” products. The trade-offs involved in different DNA approaches were discussed, with a focus on how DNA methods support existing, accepted chemical methods. In most of the products (19/20), HPLC-UV suggested the presence of Echinacea spp. While metabarcoding was not useful with this genus and instead only resolved 7 products to the family level, genome skimming was able to resolve to species (9) or genus (1) with the 10/20 products where it was successful. Additional ingredients that HPLC-UV was unable to identify were also found in four products along with the relative sequence proportion of the constituents. Additionally, genome skimming was able to identify one product that was a different Echinacea species entirely.
Recent Advances in the Selective Oxidative Dearomatization of Phenols to o-Quinones and o-Quinols with Hypervalent Iodine Reagents
Authors: Wengryniuk Sarah E. , Xiao Xiao
Published: January 2021

ortho-Quinones are valuable molecular frameworks with diverse applications across biology, materials, organic synthesis, catalysis, and coordination chemistry. Despite their broad utility, their synthesis remains challenging, in particular via the direct oxidation of readily accessible phenols, due to the need to affect regioselective ortho oxidation coupled with the sensitivity of the resulting o-quinone products. The perspective looks at the emergence of I(V) hypervalent iodine reagents as an effective class of oxidants for regioselective o-quinone synthesis. The application of these reagents in regioselective phenol oxidation to both o-quinones and o-quinols will be discussed, including a recent report from our laboratory on the first method for the oxidation of electron-deficient phenols using a novel nitrogen-ligated I(V) reagent. Also included are select examples of total syntheses utilizing this methodology as well as recent advancements in chiral I(V) reagent design for asymmetric phenol dearomatization.

1 Introduction

2 I(V): Hypervalent Iodine Reagents

3 I(V)-Mediated Dearomatization to o-Quinones

4 Bisnitrogen-Ligated I(V) Reagents: ortho Dearomatization of Electron-Poor Phenols

5 I(V)-Mediated Dearomatization to o-Quinols

6 Conclusion and Outlook
New Developments in Microbiome in Alcohol-Associated and Nonalcoholic Fatty Liver Disease
Authors: Hartmann Phillipp , Schnabl Bernd
Published: January 2021

Alcohol-associated liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) are important causes of morbidity and mortality worldwide. The intestinal microbiota is involved in the development and progression of both ALD and NAFLD. Here we describe associated changes in the intestinal microbiota, and we detail randomized clinical trials in ALD and NAFLD which evaluate treatments modulating the intestinal microbiome including fecal microbiota transplantation, probiotics, prebiotics, synbiotics, and antibiotics. Finally, we discuss precision medicine approaches targeting the intestinal microbiome to ameliorate ALD and NAFLD.
The Impact of Pulmonary Vascular Obstruction on the Risk of Recurrence of Pulmonary Embolism: A French Prospective Cohort
Authors: Orione Charles , Tromeur Cécile , Le Mao Raphael , Le Floch Pierre-Yves , Robin Philippe , Hoffmann Clément , Bressollette Luc , Nonent Michel , Le Roux Pierre-Yves , Salaun Pierre-Yves , Guegan Marie , Poulhazan Elise , Lacut Karine , Leroyer Christophe , Lemarié Catherine A. , Couturaud Francis
Published: January 2021

Background We aimed to assess whether high pulmonary vascular obstruction index (PVOI) measured at the time of pulmonary embolism (PE) diagnosis is associated with an increased risk of recurrent venous thromboembolism (VTE).

Study Design and Methods French prospective cohort of patients with a symptomatic episode of PE diagnosed with spiral computerized tomography pulmonary angiography (CTPA) or ventilation-perfusion (V/Q) lung scan and a follow-up of at least 6 months after anticoagulation discontinuation. PVOI was assessed based on the available diagnostic exam (V/Q lung scan or CTPA). All patients had standardized follow-up and independent clinicians adjudicated all deaths and recurrent VTE events. Main outcome was recurrent VTE after stopping anticoagulation.

Results A total of 418 patients with PE were included. During a median follow-up period of 3.6 (1.2–6.0) years, 109 recurrences occurred. In multivariate analysis, PVOI ≥ 40% was an independent risk factor for recurrence (hazard ratio 1.77, 95% confidence interval 1.20–2.62, p < 0.01), whether PE was provoked by a major transient risk factor or not. A threshold at 41% was identified as the best value associated with the risk of recurrence 6 months after stopping anticoagulation (area under curve = 0.64).

Conclusion PVOI ≥ 40% at PE diagnosis was an independent risk factor for recurrence VTE. Further prospective validation studies are needed.
Circulating MicroRNAs and Monocyte–Platelet Aggregate Formation in Acute Coronary Syndrome
Authors: Stojkovic Stefan , Wadowski Patricia P. , Haider Patrick , Weikert Constantin , Pultar Joseph , Lee Silvia , Eichelberger Beate , Hengstenberg Christian , Wojta Johann , Panzer Simon , Demyanets Svitlana , Gremmel Thomas
Published: January 2021

Background Monocyte–platelet aggregates (MPAs) are a sensitive marker of in vivo platelet activation in acute coronary syndrome (ACS) and associated with clinical outcomes. MicroRNAs (miRs) play an important role in the regulation of platelet activation, and may influence MPA formation. Both, miRs and MPA, could be influenced by the type of P2Y12 inhibitor.

Aim To study the association of platelet-related miRs with MPA formation in ACS patients on dual antiplatelet therapy (DAPT), and to compare miRs and MPA levels between prasugrel- and ticagrelor-treated patients.

Methods and Results We analyzed 10 circulating platelet-related miRs in 160 consecutive ACS patients on DAPT with low-dose aspirin and either prasugrel (n = 80) or ticagrelor (n = 80). MPA formation was measured by flow cytometry without addition of platelet agonists and after simulation with the toll-like receptor (TLR)-1/2 agonist Pam3CSK4, adenosine diphosphate (ADP), or arachidonic acid (AA). In multivariate regression analyses, we identified miR-21 (β = 9.50, 95% confidence interval [CI]: 1.60–17.40, p = 0.019) and miR-126 (β = 7.50, 95% CI: 0.55–14.44, p = 0.035) as independent predictors of increased MPA formation in vivo and after TLR-1/2 stimulation. In contrast, none of the investigated miRs was independently associated with MPA formation after stimulation with ADP or AA. Platelet-related miR expression and MPA formation did not differ significantly between prasugrel- and ticagrelor-treated patients.

Conclusion Platelet-related miR-21 and miR-126 are associated with MPA formation in ACS patients on DAPT. miRs and MPA levels were similar in prasugrel- and ticagrelor-treated patients.
Basilar Artery Occlusion and Emerging Treatments
Authors: Liu Zuolu , Liebeskind David S.
Published: January 2021

Basilar artery occlusion is a relatively uncommon but neurologically devastating condition. If revascularization is not achieved, the potential for death and disability is substantial. During the last several years, there have been positive endovascular stroke trials for the treatment of large vessel occlusion; however, all of them excluded patients with basilar artery occlusion. The current treatment of basilar artery occlusion is still founded on small observational studies or meta-analyses. As case selection for revascularization and treatment protocols often vary widely across institutions, sample sizes remain limited. In this article, we aim to review some of the larger observational studies in stroke due to basilar artery occlusion, considering potential treatment strategies and resultant outcomes.
Tonic Tics in Gilles de la Tourette Syndrome
Authors: Kaczyńska Justyna , Janik Piotr
Published: January 2021

Aim Tonic tics (TTs) are a part of a clinical picture of Gilles de la Tourette syndrome (GTS) and manifest themselves as sustained and isometric contraction of a muscle group devoid of the movement effect or accompanied by only slight visible motion. The aim of this study was to evaluate the prevalence and phenomenology of TTs, and to assess the clinical associations of TTs with tic severity and comorbidities in patients with GTS.

Methods We performed a one-time registration study in a cohort of 241 consecutive outpatients with GTS aged 5 to 50 years (188 males, 153 patients under the age of 18 years). All patients were personally interviewed and examined.

Results TTs occurred in 85.2% of adults and 63.9% of children and adolescents. Most frequently reported types of TTs were tensing of the abdomen (58.7%), neck (52.7%), and upper limbs (50.3%). Multivariate statistical analysis showed a significant correlation between TTs and the total number of simple tics, total number of complex tics, and age at evaluation. In the group of children and adolescents, an additional significant variable was the duration of GTS. In the group of adults, significant parameters were total number of simple tics, total number of complex tics, peak tic severity ever experienced, premonitory urges, and the presence of dystonic tics.

Conclusion TTs belong to the tic spectrum, common and early symptoms of GTS, are associated with overall a greater number of tics which are more severe, and with more comorbidities.
Topological characterization of toroidal chaos: A branched manifold for the Deng toroidal attractor
Authors: Mangiarotti Sylvain , Letellier Christophe
Published: January 2021

When a chaotic attractor is produced by a three-dimensional strongly dissipative system, its ultimate characterization is reached when a branched manifold—a template—can be used to describe the relative organization of the unstable periodic orbits around which it is structured. If topological characterization was completed for many chaotic attractors, the case of toroidal chaos—a chaotic regime based on a toroidal structure—is still challenging. We here investigate the topology of toroidal chaos, first by using an inductive approach, starting from the branched manifold for the Rössler attractor. The driven van der Pol system—in Robert Shaw’s form—is used as a realization of that branched manifold. Then, using a deductive approach, the branched manifold for the chaotic attractor produced by the Deng toroidal system is extracted from data.
Simulation of a multistage depressed collector with secondary electron emission for a MW-class gyrotron at 170 GHz
Authors: Wang Kai , Xue Qianzhong , Zhang Shan , Zhao Ding , Zhang Lianzheng
Published: January 2021

This paper presents the simulation results of a multistage depressed collector for a MW-class gyrotron. The energy distribution of spent electrons is obtained by a beam–wave interaction code. By increasing the number of depressed electrodes, the maximum collection efficiency can be increased to 81% with a low percentage of backstreaming 0.04% with regard to a four-stage depressed collector. By considering the secondary electron emission, the effects of different kinds of secondary electrons are simulated in the CST software, which is developed by Computer Simulation Technology Company in Germany. In order to reduce bad effects of secondary electrons, the structure of the fourth depressed electrode has been adjusted to form a slope. The axial length and slant angle of the slope have been optimized. The results indicate that the collection efficiency can exceed 70% and the percentage of backstreaming is less than 1%. Besides, in view of the limited power capacity of the collector wall, a magnetic field sweeping system has been introduced. The maximum power density is reduced to 392 W/cm2, and the deposited length of the electron beam trajectory is 470 mm.
Observation of asymmetric explosive density evolution in the deflagration-to-detonation transition for porous explosives
Authors: Tringe Joseph W. , Stobbe David M. , Parker Gary R. , Smilowitz Laura , Henson Bryan F. , De Haven Martin R. , Ruch Aaron J. , White Bradley W. , Reaugh John E. , Vandersall Kevin S.
Published: January 2021

We report deflagration-to-detonation transition phenomena in cylindrical columns of porous explosives based on octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). The HMX powder and LX-14 (95.5 wt. % HMX and 4.5 wt. % estane polyurethane) prills were observed with high-speed cameras and flash x rays under conditions that allow for precise scaling and registration of the recorded images. These experimental results test the conventional assumption of axisymmetric, effective one-dimensional burning. Polycarbonate confinement tubes allowed this direct imaging with steel spheres employed as radio-opaque fiducials. Spheres embedded in the explosive column revealed the displacement of the explosive prior to deflagration. X-ray and fast camera images show that a dense plug of compact explosive develops ahead of the deflagration front. The internal fiducials register both internal changes in the plug and changes in the position between successive x-ray images. Tantalum witness strips placed on the inner wall of the explosive channel revealed radial expansion of the tube bore at successive x-ray exposures, indicating the internal pressure of about 100 MPa just before detonation. Images indicate that the deflagration is not only asymmetric but also involves newly observed transient phenomena just before detonation. We typically see a brief but continuous increase in deflagration speed and the formation of a deflagration channel that bypasses the plug just prior to detonation. We hypothesize that these phenomena play an important role in the deflagration-to-detonation transition itself.
An immunohistochemical study of lymphatic elements in the human brain
Authors: Mezey Éva , Szalayova Ildikó , Hogden Christopher T. , Brady Alexandra , Dósa Ágnes , Sótonyi Péter , Palkovits Miklós
Published: January 2021

Significance

The connection between brain and peripheral lymphatics has been studied for 250 y, mainly in animals. Specific markers for lymphatic endothelial cells (LECs) were discovered about a decade ago. We stained postmortem human brains with LYVE1 and PDPN to identify LECs. Marker-positive cells were found in membranes covering the brain, walls of vessels, and perivascular spaces, and among nerve fibers. These spaces also seem to contain T cells and are connected to peripheral lymphatics through passageways in the nasal cavity, optic nerve, and base of the skull. Our findings show a path that brain waste products take when they leave the central nervous system, paths that may be bidirectional.
Reductions in 2020 US life expectancy due to COVID-19 and the disproportionate impact on the Black and Latino populations
Authors: Andrasfay Theresa , Goldman Noreen
Published: January 2021

Significance

COVID-19 has generated a huge mortality toll in the United States, with a disproportionate number of deaths occurring among the Black and Latino populations. Measures of life expectancy quantify these disparities in an easily interpretable way. We project that COVID-19 will reduce US life expectancy in 2020 by 1.13 y. Estimated reductions for the Black and Latino populations are 3 to 4 times that for Whites. Consequently, COVID-19 is expected to reverse over 10 y of progress made in closing the Black−White gap in life expectancy and reduce the previous Latino mortality advantage by over 70%. Some reduction in life expectancy may persist beyond 2020 because of continued COVID-19 mortality and long-term health, social, and economic impacts of the pandemic.
Speech language pathologists’ beliefs and knowledge-base for providing pronunciation instruction
Authors: Foote J. A. , Thomson R. I.
Published: January 2021

A number of studies have investigated the degree to which language instructors are prepared to offer pronunciation instruction (PI), but little research has addressed the readiness of another group of professionals, speech-language pathologists (SLPs), who are increasingly offering pronunciation instruction under the term foreign accent modification (FAM). To address this gap, the study reported here investigates the extent to which SLPs who offer PI are equipped to do so. We surveyed 54 SLPs who offer PI in North America, focusing on their beliefs, and the extent to which they are able to critically evaluate a range of statements and materials obtained from pronunciation resources. Results indicated that while survey respondents may have transferrable knowledge with respect to the articulation of speech sounds, many of their beliefs and practices are not grounded in a comprehensive understanding of the field. We recommend that SLPs offering PI should first receive specialized training in this area.
The statehood of Eurasia’s de facto states: an empirical model of engagement by great powers and patrons
Authors: Tokarev Aleksei , Margoev Adlan , Prikhodchenko Alexey
Published: January 2021

The article designs an empirical model to compare the level of engagement of de facto states in Eurasia by three great powers and non-great power patron states. The authors build diagrams based on three variables – military, political, and economic – whose indicators are determined by an expert survey. Russia engages the most de facto states and to the greatest degree, while the US falls behind since engaging the de facto states is not a key national security concern. However, neither holds a universal principle of engaging de facto states – each case is treated based on broader political and national security considerations. China, wary of domestic separatism, has no military ties with the de facto states and limited economic and political engagement. Taiwan scores the highest among the de facto states with the Turkish Republic of Northern Cyprus and Abkhazia falling behind by a large margin. The Peoples’ Republics of Luhansk and Donetsk and Transnistria score the lowest. The study reveals, the degree of engagement matters more than the number of the UN member states formally recognizing a de facto state.
Tidal forces are gravitational waves
Authors: Goswami Rituparno , Ellis George F R
Published: January 2021

In this paper we show in a covariant and gauge invariant way that in general relativity, tidal forces are actually a hidden form of gravitational waves. This must be so because gravitational effects cannot occur faster than the speed of light. Any two body gravitating system, where the bodies are orbiting around each other, may generate negligible gravitational waves, but it is via these waves that non-negligible tidal forces (causing shape distortions) act on these bodies. Although the tidal forces are caused by the electric part of the Weyl tensor, we transparently show that some small time varying magnetic part of the Weyl tensor with non zero curl must be present in the system that mediates the tidal forces via gravitational wave type effects. The outcome is a new test of whether gravitational effects propagate at the speed of light.
Dimension of the isometry group in three-dimensional Riemannian spaces
Authors: Ferrando Joan Josep , Sáez Juan Antonio
Published: January 2021

The necessary and sufficient conditions for a three-dimensional Riemannian metric to admit a group of isometries of dimension r acting on s-dimensional orbits are obtained. These conditions are Intrinsic, Deductive, Explicit and ALgorithmic and they offer an IDEAL labeling that improves previously known invariant studies.
Charged black hole mergers: orbit circularisation and chirp mass bias
Authors: Christiansen Øyvind , Jiménez Jose Beltrán , Mota David F
Published: January 2021

We consider the inspiral of black holes carrying U(1) charge that is not electromagnetic, but corresponds to some dark sector. In the weak-field, low-velocity regime, the components follow Keplerian orbits. We investigate how the orbital parameters evolve for dipole-dominated emission and find that the orbit quickly circularises, though not as efficiently as for a gravitationally dominated emission. We then regard circular orbits, and look for modifications in the gravitational waveform from the components carrying small charges. Taking this into account we populate the waveform with simplified LIGO noise and put it through a matched filtering procedure where the template bank only consists of uncharged templates, focusing on the charges’ effect on the chirp mass estimation. We find a consistent overestimation of the ‘generalised’ chirp mass, and a possible over- and underestimation of the actual chirp mass. Finally, we briefly consider the effect of such charges on hyperbolic encounters, finding again a bias arising from interpreting the generalised chirp mass as the actual chirp mass.
Gauge-invariant quadratic approximation of quasi-local mass and its relation with Hamiltonian for gravitational field
Authors: Jezierski Jacek , Kijowski Jerzy , Waluk Piotr
Published: January 2021

Gauge invariant, Hamiltonian formulation of field dynamics within a compact region Σ with boundary ∂Σ is given for the gravitational field linearized over a Kottler metric. The boundary conditions which make the system autonomous are discussed. The corresponding Hamiltonian functional

H

Inv

uniquely describes the energy carried by the (linearized) gravitational field. It is shown that, under specific boundary conditions, the quasi-local Hawking mass

H

Haw

reduces to

H

Inv

in the weak field approximation. This observation is a quasi-local version of the classical Brill–Deser result (Brill and Deser 1968 Ann.Phys.(N.Y.)
50 3) and enables us to declare Hawking mass as the correct expression (at least up to quadratic terms in the Taylor expansion) for the quasi-local mass, which correctly describes energy carried by the gravitational field.
Photoionization of open-shell nitrogen confined in C60
Authors: Gorczyca T W , Manson S T
Published: January 2021

Endofullerene photoionization of open-shell N@C60 is investigated using a coupled-channel, correlated R-matrix approach with additional modifications for a finite spherical-shell fullerene potential. Particular focus is on the initial-state dependence of the photoionization cross section. Comparisons show significant differences between the 1s
22s
22p
3(4S) initial state and the metastable 2D and 2P states, as well as strong confinement oscillations.
Achievement of a reversible giant magnetocaloric effect via exerting external hydrostatic pressure on a Ni45Co5Mn35In15 metamagnetic Heusler alloy
Authors: He Xijia , Zhang Yuanlei , Wei Shengxian , Cao Yiming , Xu Kun , Li Zhe
Published: January 2021

Magnetocaloric materials with first-order phase transition are potential refrigerant media for solid state refrigeration. In this work, the Ni45Co5Mn35In15 alloy possesses a representative first-order martensitic transition (MT), which is found to be sensitive to both magnetic field and isostatic pressure with rates of ∼−6.4 K T−1 and ∼4.24 K kbar−1. Such an active response to multi-stimuli derives from the strong coupling of the spin and the lattice. A low magnetic field of 1 T can drive nearly 100% of the total entropy change corresponding to the whole transformation in this alloy. However, the prominent magnetocaloric effect (MCE) is almost irreversible owing to the intrinsic hysteresis of the first-order phase transition. By virtue of the strong magnetostructural coupling during the MT, a hydrostatic pressure assisted magnetic field loading loop has been constructed for eliminating the hysteresis and to a large extent improve the reversibility of the MCE.
An ultra-broadband and optically transparent metamaterial absorber based on multilayer indium-tin-oxide structure
Authors: Deng Guangsheng , Lv Kun , Sun Hanxiao , Yang Jun , Yin Zhiping , Chi Baihong , Li Xiangxiang
Published: January 2021

In this work, an ultra-broadband and polarization-insensitive metamaterial absorber (MA) with high optical transparency is presented. Indium-tin-oxide (ITO) films are used as frequency selective surfaces in multiple conductive layers and also as the reflective backplane. Numerical simulation analysis demonstrates that the absorptivity of the proposed absorber exceeds 90% in the frequency range from 10 to 75.5 GHz, corresponding to a relative absorption bandwidth of 153%. The proposed structure has a total thickness of 2.9 mm, which is approximately 1/10 of the free space wavelength of its lowest operating frequency. The absorber also has good polarization insensitivity due to its symmetric geometry. Moreover, for TE-polarized waves, the proposed absorber can maintain an absorptivity greater than 70% for frequencies ranging from 10 to 80 GHz as the incident angle is increased to 45°. For TM-polarized waves, it provides absorptivity of more than 80% at incident angles up to 60°. Surface current distribution on each conductive ITO layer was simulated to analyze the absorption mechanism of the MA. A prototype composed of 16 × 16 unit cells was fabricated and the experimental results show a good agreement with the numerical simulations. Due to its ultra-wideband absorption and wide-incident-angle stability, the proposed MA has potential value in electromagnetic applications such as optically transparent EM shielding and microwave radiation protection.
Controlled high temperature stability of microwave plasma synthesized graphene nanosheets
Authors: Jašek Ondřej , Toman Jozef , Všianský Dalibor , Jurmanová Jana , Šnírer Miroslav , Hemzal Dušan , Bannov Alexander G , Hajzler Jan , St’ahel Pavel , Kudrle Vit
Published: January 2021

High temperature stability of nanomaterials plays an important role for their application in the field of nanocomposites, batteries, and sensors. Few-layer graphene nanosheets prepared by microwave plasma based decomposition of ethanol exhibited high thermal stability in the oxidation atmosphere in dependence on controlled formation of structural disorder. Analysis of differential thermogravimetry (DTG) curve profile showed three temperature regions, around 345 °C, 570 °C and above 700 °C, related to amorphous phase with a carbon–oxygen functional groups, small defective nanostructures and highly crystalline structure of graphene nanosheets, respectively. Raman spectroscopy and x-ray photoelectron spectroscopy (XPS) analysis of the nanosheets showed an increase of D/G Raman band ratio as well as increasing of sp3 phase content, from 6.1 at% to 15.2 at%, for highly crystalline and highly disordered structure of the nanosheets. Thermal annealing under synthetic air was used to investigate the variation in D/G and 2D/G Raman band ratio of the samples and to estimate activation energy of oxidation and disintegration process of graphene nanosheets. The highest oxidation resistance exhibited sample with high 2D/G band ratio (1.54) and lowest oxygen content of 1.7 at%. The synthesis process led to stabilization of nanosheet structure by formation of curved edges and elimination of free dangling bonds. The nanosheets prepared in microwave plasma exhibited high surface area, over 350 m2 g−1, and superior thermal stability with defect activation energy in an oxidation atmosphere higher than 2 eV. Heat release rate during the oxidation process was in correlation with the amount of disorder in the samples. Fast and easy to use technique based on high power Raman spectroscopy was developed for assessment of nanomaterial oxidation resistance.
Radiative B to axial-vector meson decays at NLO in soft-collinear effective theory
Authors: Sikandar Arslan , Aslam M Jamil , Ahmed Ishtiaq , Shafaq Saba
Published: January 2021

The rare decay B → Aγ, with A representing axial-vector mesons such as K
1(1270), K
1(1400), b
1(1300), a
1(1260), is studied at next-to-leading order (NLO) in soft collinear effective theory (SCET). The large outgoing meson energy encourages the study of the decay with an appropriate factorization scheme that separates the factorizable and non-factorizable parts systematically. We have analyzed the leading-power and

O

(

α

s

)

diagrams that contribute to matching to SCETI. The new intermediate theory is matched onto SCETII and the running of SCETI operators is performed to sum large perturbative logarithms. The values of soft-overlap function ζ
⊥ for K
1(1270, 1400), a
1 and b
1 mesons are estimated from the light cone-sum-rules, and later using it the corresponding branching fractions for

B
→

K

1

(

1270
,

1400

)

,

a

1

,

b

1

γ

decays are calculated. We find that in case of B → K
1(1270, 1400)γ decays the results are in good agreement with their experimental measurements. Also the estimated values of the branching ratios of the B → (b
1, a
1)γ decays are potentially large to be measured at the LHCb and future B-factories.
Investigating the effects of U
1 vector leptoquark on

b→uτν̄

mediated B decays
Authors: Kumbhakar Suman , Mohanta Rukmani
Published: January 2021

The recent measurements of lepton flavor universality (LFU) violating observables in semileptonic

b
→
c
ℓ

ν

̄

and b → sℓ
+
ℓ
− transitions by various experiments hint towards the possible role of new physics (NP) in

b
→
c
τ

ν

̄

and b → sμ
+
μ
− decay channels. This in turn suggests that the same class of NP as appeared in

b
→
c
τ

ν

̄

, might also show up in other tree level processes involving

b
→
u
τ

ν

̄

transition. In this paper, we study the implications of the vector leptoquark (LQ) U
1(3, 1, 2/3), which is one of the few scenarios that can simultaneously explain all the observed LFU violating signals, on the semileptonic decays

B
→

(

π
,
ρ
,
ω

)

τ

ν

̄

and

B

s

→

(

K
,

K

*

)

τ

ν

̄

. In particular, we pay our attention to the branching fractions, lepton flavor non-universality (LNU) observables, forward–backward asymmetry and the polarization asymmetry parameters of these decay modes. We find that substantial deviations in the branching fractions as well as LNU observables could be possible due to the additional contributions from U
1 LQ, which can be probed by the currently running experiments LHCb and Belle-II.
Soft mode theory of ferroelectric phase transitions in the low-temperature phase
Authors: Casella Luigi , Zaccone Alessio
Published: January 2021

Historically, the soft mode theory of ferroelectric phase transitions has been developed for the high-temperature (paraelectric) phase, where the phonon mode softens upon decreasing the temperature. In the low-temperature ferroelectric phase, a similar phonon softening occurs, also leading to a bosonic condensation of the frozen-in mode at the transition, but in this case the phonon softening occurs upon increasing the temperature. Here we present a soft mode theory of ferroelectric and displacive phase transitions by describing what happens in the low-temperature phase in terms of phonon softening and instability. A new derivation of the generalized Lyddane–Sachs–Teller (LST) relation for materials with strong anharmonic phonon damping is also presented which leads to the expression ɛ
0/ɛ
∞ = |ω
LO|2/|ω
TO|2. The theory provides a microscopic expression for T
c as a function of physical parameters, including the mode specific Grüneisen parameter. The theory also shows that

ω

T
O

∼

(

T

c

−
T

)

1
/
2

, and again specifies the prefactors in terms of Grüneisen parameter and fundamental physical constants. Using the generalized LST relation, the softening of the TO mode leads to the divergence of ϵ
0 and to a polarization catastrophe at T
c. A quantitative microscopic form of the Curie–Weiss law is derived with prefactors that depend on microscopic physical parameters.