bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution of local structure and superconductivity in CaFe2As2
Authors: Pandeya Ram Prakash , Pramanik Arindam , Sakhya Anup Pradhan , Mondal Rajib , Yadav A K , Jha S N , Thamizhavel A , Maiti Kalobaran
Published: February 2021

We investigate the evolution of the local structural parameters and their implication in unconventional superconductivity of 122 class of materials employing extended x-ray absorption fine structure studies. The spectral functions near the Fe K- and As K-absorption edges of CaFe2As2 and its superconducting composition, CaFe1.9Co0.1As2 (T
c = 12 K) exhibit evidence of enhancement of Fe contributions near the Fermi level with Co substitution, which becomes more prominent at low temperatures indicating enhanced role of Fe in the electronic properties with doping. As–Fe and Fe–Fe bondlengths derived from the experimental data reveal evolution with temperature across the magneto-structural transition in the parent compound. The evolution of these parameters in Co-doped superconducting composition is similar to its parent compound although no magneto-structural transition is observed in this system. These results reveal an evidence of doping induced evolution to the proximity to critical behavior and/or strong nematic fluctuations which might be important for superconductivity in this system.
Fault diagnosis of a rolling bearing based on the wavelet packet transform and a deep residual network with lightweight multi-branch structure
Authors: Xiong Shoucong , Zhou Hongdi , He Shuai , Zhang Leilei , Shi Tielin
Published: February 2021

Deep residual networks (DRNs) are a state-of-the-art deep learning model used in the data-driven fault diagnosis field. Their especially deep architectures give them sufficient capacity to deal with very complex diagnosis issues. However, a neural network with excellent performance usually requires hundreds of thousands of parameters, which is unaffordable for use in current industrial machines due to their limited computational resources. To enable practical applications for fault diagnosis, developing deep learning methods that can perform powerfully and have an economical computational burden is necessary. This study proposes a novel bearing fault diagnosis method based on the wavelet packet transform (WPT) and a lightweight variant of DRN called a multi-branch deep residual network (MB-DRN) in order to resolve the above issues. WPT is utilized to map raw signals into the time-frequency domain, from which the MB-DRN can extract a set of robust features more easily. Additionally, MB-DRN builds several small-sized convolutional layer branches in each building block to increase the network non-linearity, the construction of layer branches can be achieved freely and this design strategy largely saves the parameter usage while approaching a stronger model’s capacity. Two rolling bearing datasets with variable operating conditions were conducted on the proposed method to validate performance. The results verify the necessity of the WPT-based data processing method and show that MB-DRN can outperform the accuracies of standard DRN with only one quarter of the parameter amount, revealing the significant potential of the proposed method for realistic industrial fault diagnosis applications.
Improved responsivity of MgZnO film ultraviolet photodetectors modified with vertical arrays ZnO nanowires by light trapping effect
Authors: Fei Xiaomiao , Jiang Dayong , Zhao Man , Deng Rui
Published: February 2021

The light trapping effect of ZnO nanowires (NWs) is attracting increasing attention as it effectively enhances the photoelectric effect. In this paper, high-density ZnO NWs are grown on a metal–semiconductor–metal structure MgZnO film UV photodetector (PD) as a light trapping unit. The photogenerated carriers diffuse along the longitudinal axis of the ZnO NWs, then diffuse onto the thin film and are collected by an applied bias electrode. When the device is connected to the NWs, the responsivity is about 12 times higher than that of the pure MgZnO film UV PD with a large light-dark current ratio (4.93 × 104). The array structure of the ZnO NWs enhances the number of photogenerated carriers at the top interface and provides a longer optical path length and a larger surface area. The resulting light trapping effect endows the device with excellent photoelectric properties. In this work, the introduction of NWs not only fundamentally improves the performance of the MgZnO thin film UV PD, but the resulting photodetector also demonstrates a sharp contrast between light trapping UV PD and the MgZnO thin film UV PD.
Silver decorated 2D nanosheets of GO and MoS2 serve as nanocatalyst for water treatment and antimicrobial applications as ascertained with molecular docking evaluation
Authors: Qumar U , Hassan J , Naz S , Haider A , Raza A , Ul-Hamid A , Haider J , Shahzadi I , Ahmad I , Ikram M
Published: February 2021

In this work, synthesis of graphene oxide (GO) and reduced graphene oxide (rGO) was realized through a modified Hummers route. Different concentrations (5 and 10 wt%) of Ag were doped in MoS2 and rGO using a hydrothermal technique. Synthesized Ag-MoS2 and Ag-rGO were evaluated through XRD that confirmed the hexagonal structure of MoS2 along with the transformation of GO to Ag-rGO as indicated by a shift in XRD peaks while Mo–O bonding and S=O functional groups were confirmed with FTIR. Morphological information of GO and formation of MoS2 nanopetals as well as interlayer spacing were verified through FESEM and HRTEM respectively. Raman analysis was employed to probe any evidence regarding defect densities of GO. Optical properties of GO, MoS2, Ag-rGO, and Ag-MoS2 were visualized through UV–vis and PL spectroscopy. Prepared products were employed as nanocatalysts to purify industrial wastewater. Experimental results revealed that Ag-rGO and Ag-MoS2 showed 99% and 80% response in photocatalytic activity. Besides, the nanocatalyst (Ag-MoS2 and Ag-rGO) exhibited 6.05 mm inhibition zones against S. aureus gram positive (G+) and 3.05 mm for E. coli gram negative (G-) in antibacterial activity. To rationalize biocidal mechanism of Ag-doped MoS2 NPs and Ag-rGO, in silico molecular docking study was employed for two enzymes i.e. β-lactamase and D-alanine-D-alanine ligase B (ddlB) from cell wall biosynthetic pathway and enoyl-[acylcarrier-protein] reductase (FabI) from fatty acid biosynthetic pathway belonging to S. aureus. The present study provides evidence for the development of cost-effective, environment friendly and viable candidate for photocatalytic and antimicrobial applications.
Estimation of heavy tails in optical non-linear processes
Authors: Rácz Éva , Ruppert László , Filip Radim
Published: February 2021

In optical non-linear processes, rogue waves can be observed, which can be mathematically described by heavy-tailed distributions. These distributions are special since the probability of registering extremely high intensities is significantly higher than for the exponential distribution, which is most commonly observed in statistical and quantum optics. Our work provides a practical overview of the generic statistics toolkit concerning heavy-tailed distributions and proposes methods to deal with issues specific to non-linear optics. We take a closer look at supercontinuum generation, where rogue waves were already observed. We propose modifications to the Hill estimator to deal with detector saturation as well as corrections introduced by pumping the process by bright squeezed vacuum. The suggested methodology facilitates statistically reliable observation of heavy-tailed distribution in non-linear optics, nano-optics, atomic, solid-state processes, and optomechanics.
An AC quantum voltmeter for frequencies up to 100 kHz using sub-sampling
Authors: Behr Ralf , Palafox Luis
Published: February 2021

Differential sampling relative to a Josephson waveform, the ac quantum voltmeter (ac-QVM), has been established as the most accurate method for measuring signals below 1 kHz with an uncertainty of 1 part in 108 (k = 1) for 1 V at 250 Hz. Commercial ac-QVMs provide accuracies of about 1 part in 106 up to frequencies of 2 kHz. Here we present a new sub-sampling technique to extend the frequency range of an ac-QVM up to 100 kHz. The measurement results at 1 V RMS amplitude agree well within 5 µV V−1 (k = 1) with the nominal voltage values for all frequencies from 500 Hz to 100 kHz. Two different analogue-to-digital converters are compared, sampling techniques, error sources and corrections as well as detailed uncertainty estimations are discussed.
Prospecting of the collision electron spectroscopy method and its integration into personal microplasma photoionization sensor CES
Authors: Tsyganov A B , Arslanova F G , Kamenev E N , Odintsov E E
Published: February 2021

The method of Collision Electron Spectroscopy (CES), which allowed the plasma research group of St. Petersburg Mining University to develop an innovative photoionization sensor, has several applied advantages over existing analog molecular detection methods currently used at enterprises. Though, the rate of global consumption of products manufactured at enterprises increases, which has a high risk of threat to human life and health, most developers are not able to meet the increased level of international quality standards for measuring instruments. The CES method not only makes it possible to increase the accuracy of modern measuring equipment at times, but makes the gas analyzer device portable, increases autonomy, and also significantly reduces the device’s dimensions, which, as a result, allows the device to be used as an individual portable sensor and used for diagnostics health conditions at home.
Experimental investigation of interrupting capacity of low voltage circuit breaker
Authors: Kvashnin A , Murashov Iu , Frolov V
Published: February 2021

The experimental results of the circuit breaker interrupting capacity are presented in the article. The scheme of the experimental workbench and diagnostic methods are described. The study was performed using high-speed shooting methods. The high-speed shooting results and diagrams for different modes are presented. The analysis of the arc divider geometry influence on the extinguishing process for different modes and power factor is completed. A parametric study of the influence of the power factor, the interrupting current magnitude and the moment of switching on the extinction of the electric arc in the circuit breaker is also performed. The influence of the arc chute geometry on the formation of a new arc attachment point is shown in the article. The test was carried out on the basis of a specially developed prototype of a low-voltage circuit breaker (AC). The obtained results can be used when designing a low-voltage circuit breaker (AC).
Simulation of the process of extruding a bar billet into a cylindrical extrusion die with active friction
Authors: Larin S N , Korotkov V A , Isaeva A N , Pasynkov A A
Published: February 2021

Backward extrusion processes are widespread when producing various axisymmetric hollow products. This process is characterized by high values of specific pressures. The meaningful task to be achieved is to reduce loads during this process implementation. The use of active friction forces to reduce loads seems to be promising. The use of a floating die with a protrusion on a cylindrical surface, which will facilitate the billet material pushing, is proposed. For theoretical justification of the process, the provision is made to use the finite-element method. The procedure was simulated for different geometric relationships of the tool, the floating extrusion die path velocities and the billet position relative to the extrusion die. The provision is made to analyze the influence of deformation parameters and velocity parameters on the change in force of the studied procedure. Based on the research findings, the conclusions on the expediency of the studied method use for its practical implementation have been made.
Modeling wear process of oil scraper piston rings with pyrolytic chromium coating
Authors: Maksarov V V , Krasnyy V A , Klochkov D A
Published: February 2021

The modern designs of oil scraper piston rings of internal combustion engines, including box-section rings with an expander are considered. Pyrolytic carbide of chrome coating of the working edges of oil scraper piston rings are proposed as a possible alternative to galvanic chromium coating. The results of model tribotechnical samples tests, which showed the effectiveness of pyrolytic chromium carbide plating in comparison with galvanic coating with chromium, are presented. Under the same conditions the wear of samples with pyrolytic chromium plating is 3.5 … 4 times less. It is shown that pyrolytic carbide chromium coating is promising for piston oil scraper rings.
Individual parameters of dark and light radiators powered by complex waveform current
Authors: Ptitsyna E V , Kuvaldin A B , Ptitsyn D V
Published: February 2021

The power factor is an important indicator of the installations efficiency with light and dark infrared radiators, their individual characteristics. The efficiency of installations depends on used electrical mode. In this paper, the object and subject of research are infrared ceramic lamps for heating, flexible heating tapes for electric heating systems, light infrared radiators and their operation modes powered by complex waveform current. The purpose of the research is the individual parameters of infrared radiators when the amplitude and frequency of the supply voltage are changing and develop recommendations on the choice of effective modes. The authors have solved the following tasks: to develop a method to research the physical models of installations with infrared radiators and to develop recommendations to choose the effective load operating modes based on the results of energy parameters measurements. The authors have obtained the following values of the power factor in the normal and new modes: the ceramic lamp and light radiator–0.97, the flexible heating tape - 0.83. In addition, the authors have proved that the harmonic composition of supply voltage did not deteriorate in the new mode.
Consumed power regulation algorithm in the presence of high harmonics
Authors: Skamyin A N , Rastvorova I V
Published: February 2021

The study of the effect of voltage on the parameters of power consumption in the presence of high harmonics in the electric network was conducted. The research was carried out with various types of loads, voltage regulation devices and reactive power compensation on the laboratory installation. It was found that, taking into account the minimization of voltage distortions, power consumption can be regulated by varying the voltage at the transformer output depending on the location of the harmonic distortion source. Based on the studies, an algorithm for power consumption regulation in the presence of high harmonics was developed. It allows minimizing the active, reactive power and distortion power while providing standardized values of the voltage total harmonic distortion ratio.
Structure modeling of mining machinery systems for production of raw peat materials
Authors: Ivanov S L , Iakupov D R , Ivanova P V , Permiakova E K
Published: February 2021

This work describes systems of mining machines for peat extraction, particularly, the systems that exploit environment-friendly technologies. An algorithm for schematic structure modeling of modular mining machinery systems was introduced and analyzed. Based on the analysis, an algorithm for assessing energy consumption of an entire machinery system on the basis of its structure was described. As an example, structural schemes of four modular mining machinery systems were assessed. These structural formulae were also used for structuring mining machinery systems by the energy efficiency criterion. Effectiveness value of mining machinery system is suggested to be assessed by energy efficiency coefficient. The results of the analysis and assessed models proved the viability of mining machinery systems for open-cast peat winning that combine the modules of extraction, processing, transfer, and others organized by applying devised structural formulae and energy efficiency criterion.
Modeling of the molten glass formation zone as a viscoelastic medium
Authors: Alekseeva L B , Maksarov V V
Published: February 2021

The article studies mathematical models that describe the movement of a viscoelastic medium. The equations of continuity, balance of forces and physical equations describing the glass melt have been created. When studying the behavior of molten glass in the formation zone, it is considered as a viscous liquid, as a viscoelastic liquid (Maxwell’s model) and as an elastic-viscous body. A system with boundary conditions is a problem of movement of the viscoelastic medium with a lower movable boundary.
Android Application Development of Student Learning Skills in Era Society 5.0
Authors: Nugraha Ariadi , Aminur Rahman Fuad
Published: February 2021

The aim of this paper is to discuss the android application development of student learning skills in the era 5.0. Era of society 5.0 is an era that requires every student and people to be able to have critical and constructive thinking skills, it tries to better prepare its human resources as a filter for the challenges posed by industry 4.0 which gave birth to various innovations and industrialization. With the coming of the era of Society 5.0, it is expected to be able to resolve problems and gaps in the virtual and social world systems. To realize or prepare era society 5.0 in the field of education especially in Indonesia, children need to be able to have critical, constructive and innovative ways of thinking and an appropriate understanding of their learning abilities. Therefore, from the above explanation, the development of android application of student learning skills in the era of 5.0 is needed, this is done to support the development of students in their education, especially in the era of society 5.0.
Multimedia with Social Learning Networks (SNL): As Learning Innovation in the 4.0 Industrial Era
Authors: Ramadhan Syahrul , Atmazaki  , Sukma Elfia , Indriyani Vivi
Published: February 2021

Technological advances have opened the door to present instructional material in various forms such as audio, visual, printed text, images, and moving images. All types of multimedia are found in one computer, which has opened the way to present learning more effectively. In addition, there were also many networking sites specifically used in learning to facilitate online learning. However, to integrate technology in learning cannot be adopted directly, it is necessary to innovate and adapt to the curriculum and learning. Based on that, it is necessary to develop a language learning model based multimedia using Social Lerning Network (SNL). This type of research is Research & Development (R&D) with a 4-D development model (define, design, develop, and disseminate). The results showed that the learning model developed was categorized as very valid and could be tested in schools.
Simulations of microturbulence in magnetised plasmas using a delta-f gyrokinetic approach with an evolving background Maxwellian
Authors: Murugappan Moahan , Donnel Peter , Brunner Stephan , Villard Laurent
Published: February 2021

The gyrokinetic delta-f particle-in-cell (PIC) approach is known to be successful for simulating turbulence in the core of magnetic fusion plasmas, where fluctuations are relatively small and therefore the unperturbed particle distribution function, usually represented by a stationary Maxwellian f
0, remains a good choice of a control variate for reducing statistical sampling noise. However, towards the plasma edge, characterized by low density and temperature and strong gradients, relative deviation amplitudes typically become large, so that the essential assumption of |δf/f
0| << 1 underlying the delta-f PIC approach will not be valid, where δf is the fluctuating part of distribution. This motivates the study of the limits of the delta-f approach in a simplified system mimicking the plasma edge. To this end, simulations are run using GK-engine, which is a delta-f PIC code that solves the nonlinear gyrokinetic equation in a sheared slab geometry, using B-spline finite elements to represent the self-consistent electrostatic field. Initial radial density and ion temperature profiles exhibiting high logarithmic gradients representing plasma edge conditions are used. In order to avoid practical problems of particles exiting the simulation domain as the ion temperature profile relaxes, all profiles are mirrored at domain-centre and periodic boundary conditions are imposed. The validity of the delta-f approach is measured by statistical noise estimates, while monitoring relative deviation levels of temperature via the kinetic energy. In particular, the effect of background profile gradients on these measures is investigated. As a first step towards reducing the amplitude of the deviation δf, an adaptive Maxwellian f
0 is implemented, whose time dependent temperature profiles are obtained by locally relaxing kinetic energy accumulating in δf into f
0.
Optically active quadrupole edge modes in arrays of flat metallic nanodisks
Authors: Sadeghi Seyed M , Wing Waylin J , Gutha Rithvik R
Published: February 2021

Using experimental and simulation methods, we demonstrate that structures consisting of two-dimensional arrays of closely-packed flat metallic nanodisks can support optically active collective resonances associated with the dark edge modes. Our results show that such resonances appear as the refractive index of the superstrate increases, generating a relatively sharp peak with weak sensitivity to the variations of the environment. Using a consecutive multilayer deposition of Si on the top of the arrays we map the development of such a resonance via multi-step red shifting of the Rayleigh anomaly wavelength. The results show that when the Rayleigh wavelength is sufficiently close to the subradiant quadrupole edge modes of the nanodisks, a linearly polarized light can excite such modes, resulting in optically active collective resonance.
Highly-efficient wavefront bending with a single-layer perforated metasurface
Authors: Xiao Wan-yue , Huang Cheng-ping
Published: February 2021

Simultaneous control of transmission amplitude and phase in optical regime has been theoretically demonstrated, employing a single-layer metal film milled with rectangular grooves and holes that are orthogonal to each other. By designing the configuration and sizes of nano-apertures, a single outgoing polarization with field transmission coefficient of ∼0.8 and transmission phase shift covering the full 2π range can be achieved. Moreover, with the phase gradient along the surface of super-cells consisting of six sub-units, anomalous positive and negative refraction with a high efficiency (∼60%) was suggested. This perforated metasurface may provide an alternative and efficient platform for controlling light.
The Association between the Alcohol Biomarker Phosphatidylethanol (PEth) and Self-Reported Alcohol Consumption among Russian and Norwegian Medical Patients
Authors: Jørgenrud Benedicte , Kabashi Saranda , Nadezhdin Aleksei , Bryun Evgeny , Koshkina Evgenya , Tetenova Elena , Lerdal Anners , Norby Gudmund , Kolgashkin Alexey , Petukhov Alexei , Perekhodov Sergey , Davydova Elena , Vindenes Vigdis , Gamboa Danil , Bogstrand Stig Tore
Published: February 2021

Aims

Valid measures to identify harmful alcohol use are important. Alcohol Use Disorders Identification Test (AUDIT) is a validated questionnaire used to self-report harmful drinking in several cultures and settings. Phosphatidylethanol 16:0/18:1 (PEth) is a direct alcohol biomarker measuring alcohol consumption levels. The aim of this study was to investigate how PEth levels correlate with AUDIT-QF and weekly grams of alcohol consumed among patients in two urban hospitals. In addition, we wanted to investigate the predictive value of PEth in identifying harmful alcohol use as defined by AUDIT-QF and weekly grams of alcohol cutoffs.

Methods

A cross-sectional study comprising acute medically ill patients with measurable PEth levels (≥0.030 μM) admitted to two urban hospitals in Oslo, Norway (N = 931) and Moscow, Russia (N = 953) was conducted using PEth concentrations in whole blood, sociodemographic data and AUDIT-QF questionnaires.

Results

PEth levels from patients with measurable PEth were found to be positively correlated with AUDIT-QF scores, with PEth cutpoints of 0.128 μM (Oslo) and 0.270 μM (Moscow) providing optimal discrimination for harmful alcohol use defined by AUDIT-QF (the difference between cities probably reflecting different national drinking patterns in QF). When converting AUDIT-QF into weekly grams of alcohol consumed, the predictive value of PEth improved, with optimal PEth cutpoints of 0.327 (Oslo) and 0.396 (Moscow) μM discriminating between harmful and non-harmful alcohol use as defined in grams (≥350 grams/week).

Conclusions

By using PEth levels and converting AUDIT-QF into weekly grams of alcohol it was possible to get an improved rapid and sensitive determination of harmful alcohol use among hospitalized patients.
Web wars: males of the golden orb-web spider invest more in fights for mated females
Authors: da Silva Amanda Vieira , Oliveira Reisla , Peixoto Paulo Enrique Cardoso
Published: February 2021

In addition to resource value, the cost of finding mates may affect how much males invest in fights for females. The cost of finding females may be imposed through natural factors extrinsic to males, such as female spatial distribution and predation pressure, which can be challenging to simulate in laboratory conditions. Therefore, studies under natural conditions may be suitable for understanding how the costs of finding mating partners affect male investment in fights. We used the spider Trichonephila clavipes to evaluate the hypotheses that males in field conditions invest more in contests for access to 1) unmated and 2) more fecund females and 3) when access to females is harder. To test these hypotheses, we recorded the occurrence, duration, and escalation of induced contests between males located in webs of females that differed in reproductive status (estimated by female life stage), fecundity (estimated by female abdominal area), and spatial distribution (i.e., isolated or aggregated with webs of other females). The occurrence and duration of contests were unrelated to female value or search costs. However, the probability for escalation was higher when males were fighting for adult (and probably mated) females. We also found that males tended to start a contest more often in aggregated webs. These results indicate that males of T. clavipes adjust investment in contests but contrarily to what we expected. We suggest that males invest more in contests for adult females because they are defending females that they previously fertilized to avoid sperm competition.
HiCRep.py: fast comparison of Hi-C contact matrices in Python
Authors: Lin Dejun , Sanders Justin , Noble William Stafford
Published: February 2021

Motivation

Hi-C is the most widely used assay for investigating genome-wide 3D organization of chromatin. When working with Hi-C data, it is often useful to calculate the similarity between contact matrices in order to assess experimental reproducibility or to quantify relationships among Hi-C data from related samples. The HiCRep algorithm has been widely adopted for this task, but the existing R implementation suffers from run time limitations on high-resolution Hi-C data or on large single-cell Hi-C datasets.

Results

We introduce a Python implementation of HiCRep and demonstrate that it is much faster and consumes much less memory than the existing R implementation. Furthermore, we give examples of HiCRep’s ability to accurately distinguish replicates from non-replicates and to reveal cell type structure among collections of Hi-C data.

Availability and implementation

HiCRep.py and its documentation are available with a GPL license at https://github.com/Noble-Lab/hicrep. The software may be installed automatically using the pip package installer.

Supplementary information

Supplementary data are available at Bioinformatics online.
Rights-Based Social Work and the Named Social Worker for Adults with Learning Disabilities: A Policy Intervention 50 Years in the Making
Authors: James Elaine
Published: February 2021

There has been a renewed interest in professional and academic discourse in the reconceptualisation of social work with adults as a human rights-based approach. This is compatible with the social model of disability, which philosophically adult social workers make claims to align with. This was recently argued for when the Department of Health in England piloted a named social worker for adults with learning disabilities, whose behaviour challenged services. This paper discusses the conceptualisation of rights-based practice, its relevance and appropriateness for contemporary social work policy. Drawing on the recognition theory literature, it shall be shown that the meta-theory of rights-based practice may have relevance to contemporary social work practice with adults with learning disabilities. The paper shall also consider the renewed interest in normative reconstruction in social work practice and influencing factors such as drives towards individualism and marketisation. It will consider how these impacted on the adoption into UK policy of social work as a positive intervention to address structural inequalities, perhaps more accurately described as disablism, experienced by adults with learning disabilities, which ultimately is concluded to be a ‘wicked problem’.
AQbD-Oriented UHPLC/MS/MS Method Development for Glycopeptides Assessment in Pharmaceutical Forms
Authors: Stajić A , Janković-Maksić J , Jančić-Stojanović B , Medenica M
Published: February 2021

Vancomycin and teicoplanin are glycopeptide antibacterials that inhibit the bacteria cell wall synthesis showing activity against gram-positive bacteria.

Development of the sensitive method is of great importance for quality control of these drugs that are fermentation products. Modification of the fermentation conditions could cause the differences in the relative amount of the total substance or component, as it is the case with teicoplanin. The main objective of this study was development of the sensitive and effective ultra high performance liquid chromatography - tandem mass sprectrometry (UHPLC-MS/MS) method for simultaneous quantification of vancomycin, all six subcomponents of teicoplanin, and its pharmacopoeial impurity A in pharmaceutical forms. The scientific-based Quality by Design approach was implemented in the MS and UHPLC method development. Detection and quantification of analytes were carried out in positive electrospray ion mode by multiple reaction monitoring. Capillary voltage, cone voltage and collision energy were optimized by implementing experimental design methodology and optimal values for each fragment ion were obtained by performing experiments according to ‘Rechtschaffen’ design matrix. An ACQUITY CSH Phenyl-hexyl (2.1 × 50 mm, particle size 1.7 μm) column was chosen for the separation under the gradient elution mode with the mobile phase consisted of 0.1% formic acid in water (mobile phase A) and acetonitrile (mobile phase B). Optimal gradient elution parameters were achieved by applying ‘Rechtschaffen’ design too. Method operable design regions were constructed for investigated MS and chromatographic parameters. The method was fully validated, and its applicability was confirmed throughout the ability to follow the behavior of vancomycin and teicoplanin under stress conditions.
miR-24-3p regulates CDX2 during intestinalization of cardiac-type epithelium in a human model of Barrett’s esophagus
Authors: Gil-Gómez Gabriel , Fassan Matteo , Nonell Lara , Garrido Marta , Climent Marta , Anglada Roger , Iglesias Mar , Guzzardo Vicenza , Borga Chiara , Grande Luis , de Bolós Carme , Pera Manuel
Published: February 2021

Background

Cardiac-type epithelium has been proposed as the precursor of intestinal metaplasia in the development of Barrett’s esophagus. Dysregulation of microRNAs (miRNAs) and their effects on CDX2 expression may contribute to intestinalization of cardiac-type epithelium. The aim of this study was to examine the possible effect of specific miRNAs on the regulation of CDX2 in a human model of Barrett’s esophagus.

Methods

Microdissection of cardiac-type glands was performed in biopsy samples from patients who underwent esophagectomy and developed cardiac-type epithelium in the remnant esophagus. OpenArray™ analysis was used to compare the miRNAs profiling of cardiac-type glands with negative or fully positive CDX2 expression. CDX2 was validated as a miR-24 messenger RNA target by the study of CDX2 expression upon transfection of miRNA mimics and inhibitors in esophageal adenocarcinoma cell lines. The CDX2/miR-24 regulation was finally validated by in situ miRNA/CDX2/MUC2 co-expression analysis in cardiac-type mucosa samples of Barrett’s esophagus.

Results

CDX2 positive glands were characterized by a unique miRNA profile with a significant downregulation of miR-24-3p, miR-30a-5p, miR-133a-3p, miR-520e-3p, miR-548a-1, miR-597-5p, miR-625-3p, miR-638, miR-1255b-1, and miR-1260a, as well as upregulation of miR-590-5p. miRNA-24-3p was identified as potential regulator of CDX2 gene expression in three databases and confirmed in esophageal adenocarcinoma cell lines. Furthermore, miR-24-3p expression showed a negative correlation with the expression of CDX2 in cardiac-type mucosa samples with different stages of mucosal intestinalization.

Conclusion

These results showed that miRNA-24-3p regulates CDX2 expression, and the downregulation of miRNA-24-3p was associated with the acquisition of the intestinal phenotype in esophageal cardiac-type epithelium.
Impact on clinical outcomes of right ventricular response to percutaneous correction of secondary mitral regurgitation
Authors: Caiffa T , Castrichini M , Biagini E , De Luca A , Compagnone M , Berardini A , Merlo M , Fabris E , Vitrella G , Pinamonti B , Korcova R , Barbati G , Saia F , Stolfo D , Sinagra G
Published: February 2021

Funding Acknowledgements

Type of funding sources: None.

Background. Right ventricular function (RVF) is a strong determinant of prognosis in patients with reduced ejection fraction heart failure (HFrEF) and secondary mitral regurgitation (SMR). Percutaneous mitral valve repair (pMVR) can promote the recovery of RVF.

Purpose. We sought to characterize the RV response to pMVR in HFrEF with SMR and to assess the influence of improved RVF after pMVR in this specific setting of patients.

Methods. We included all the patients with HFrEF and SMR≥3+ successfully treated with pMVR between April 2012 and January 2020 in two tertiary care centers for HF. Improved RVF was defined as DRVFAC≥5% at early follow-up (median time 4 months). The primary endpoint was a composite of death/heart transplant (D/HT).  

Results. In total, 110 patients were included. Mean age was 67 ± 12 years, mean LVEF was 31 ± 8% and mean RVFAC was 31 ± 10%. DRVFAC≥5% occurred in 54 (49%) patients and was independent from the measures of left ventricle recovery. During a median follow-up of 36 months (IQR 19-52), 40 patients (36%) died or were transplanted.  After adjustment for other significant covariates, DRVFAC≥5% was significantly associated with lower risk of D/HT (HR 0.49, 95% CI 0.24 – 0.98 p < 0.042) along with M2+ at follow-up (HR 0.36; 95% CI 0.17-0.74 p 0.005).

Conclusions. In patients with HFrEF and SMR, the improvement of RVF is frequent after pMVR and is associated with better long-term survival free from HT.

Abstract Figure.
Evaluation of left atrial volume in obesity. How indexation by body surface compares to indexation by height
Authors: Azzari F , Krsticevic L , Dionne N , Veilleux SP , Rioux L
Published: February 2021

Funding Acknowledgements

Type of funding sources: None.

Background

 

Left atrial enlargement (LAE) is a risk factor for atrial fibrillation, stroke and heart failure with preserved ejection fraction. Current ASE/EACVI guidelines recommend indexing left atrial volume (LAV) by body surface area (BSA) for LAE grading. However, in overweight patients, this ratio must be interpreted with caution due to a disproportionate increase in BSA.

Purpose

  

We have assessed LAE in overweight (OW), obese (OB) and severely obese (SO) patients by indexing LAV by height (Ht) instead of BSA.

Methods

 

We retrospectively evaluated LAV in 1246 patients from our echocardiography clinic.

We graded LAE by BSA, in patients with a normal body mass index (BMI ≥18.5 and <25 kg/m², n = 422). Afterwards, we established the cut-offs for the LAV/Ht ratio by the receiver operating curve (ROC) method. We reported sensitivity (Se), specificity (Sp), area under ROC curve (AUC) and Youden’s index (Yi).

Finally, we applied the LAV/Ht ratio to OW (BMI ≥25 and <30 kg/m², n = 467), OB (BMI ≥30 and <35 kg/m², n = 235) and SO (BMI ≥35 kg/m², n = 122) patients.

Results

 

There were no differences in Ht between groups. As expected, the weight (63.2 ± 8.8, 77.4 ± 9.6, 91.7 ± 11.5 and 110.4 ± 17.3 kg) and BSA were significantly different in between groups.

The cut-offs for the LAV/Ht ratio were ≥35 ml/m (Se 96.3%, Sp 97.3%, AUC 0.997, Yi 0.94), ≥42 ml/m (Se 100%, Sp 96.7%, AUC 0.996, Yi 0.97) and ≥48 ml/m (Se 94.3%, Sp 97.0%, AUC 0.954, Yi 0.94) for mild, moderate and severe LAE, respectively.

The table shows LAV and LAE grading according to BMI group. When applying the LAV/Ht ratio, the LAE grade increased in 29.8% of OW, 48.5% of OB and 66.4% of SO patients.

Conclusion(s): 

LAV is significantly increased in OW, OB, and SO patients.

In this population, the LAV/BSA ratio significantly underestimates the degree of LAE. The LAV/Ht ratio allows an accurate categorization of LAV, leading to a significant reclassification of LAE.

Normal Weight Overweight Obese Severely Obese LAV (ml) ¶ 58.3 ± 26.4 63.5 ± 24.0 69.3 ± 25.7 76.4 ± 25.1 LAV/BSA (ml/m2) 33.9 ± 14.2 33.8 ± 12.1 34.3 ± 11.9 35.3 ± 10.7 Normal / Mild 64.5 / 15.4% 63.2 / 19.3% 64.3 / 16.2% 54.1 / 23.8% Moderate / Severe 7.6 / 12.6% 6.9 / 10.7% 8.9 / 10.6% 10.7 / 11.5% LAV/Ht (ml/m) 34.7 ± 15.0 37.6 ± 13.6 41.0 ± 14.6 45.9 ± 14.4 Normal / Mild – 50.3 /20.1% 39.1 / 25.1% 21.3 / 23.0% Moderate / Severe – 13.9 / 15.6% 13.2 / 22.6% 18.9 / 36.9% ¶ ANOVA between BMI groups: <0.0001; Comparison between LAE grading by BSA or Ht: OW χ²=22.4, p = 0.0001; OB χ²=30.8, p < 0.0001; SO χ²=36.5, p = 0.0001
Echocardiographic phenotypes of patients with sickle cell disease. An unsupervised analysis based on etendard cohort
Authors: D"humieres T , Inamo J , Deswarte S , Damy T , Loko G , Lionnet F , Humbert M , Derumeaux G , Savale L , Bartolucci P
Published: February 2021

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): PHRC

Backgroung

Echocardiography is the cornerstone in the diagnosis of cardiopulmonary involvement in sickle cell disease (SCD). However, given the unique pathophysiology of SCD associating high cardiac output, and various degrees of peripheral vasculopathy, differentiate the pathological from the physiological using echocardiography can be particularly challenging.

Purpose

This study sought to link cardiac phenotypes in homozygous SCD patients with clinical profiles and outcomes using cluster analysis.

Methods

We analyzed data of 379 patients with a sufficient echographic dataset included in the French Etendard Cohort, a prospective cohort initially designed to assess the prevalence of pulmonary hypertension. A cluster analysis was performed on echocardiographic variables, and the association between clusters and clinical profiles and outcomes was assessed.

Results

Three clusters were identified. Cluster 1 (N = 122) patients had the lowest cardiac output, only mild left cavities remodeling, diastolic dysfunction, and high tricuspid regurgitation velocity (TRV). They were predominantly female, as old as cluster 2, and displayed the most severe functional limitation. Cluster 2 (N = 103) patients had the highest cardiac output, left ventricular mass and a severely dilated left atrium. Diastolic function and TRV were similar to cluster 1. These patients had a higher blood pressure and a severe hemolytic anemia. Cluster 3 (N = 154) patients had mild left cavities remodeling, the best diastolic function and the lowest TRV. They were younger patients with the highest hemoglobin and lowest hemolytic markers. Right heart catheterization was performed in 94 patients. Cluster 1 gathered the majority of precapillary PH while cluster 2 gathered postcapillary PH and no PH was found in cluster 3. After a follow-up of 9.9 years (IQR: 9.3 to 10.5 years) death occurred in 38 patients (10%). Clusters 2 had the worst prognosis with 18% mortality rate vs. 12% in cluster 2 and 5% in cluster 1 (P log-rank = 0,02). Results are summarized in the central illustration.

Conclusions

Cluster analysis of echocardiographic variables identified 3 phenotypes among SCD patients, each associated with different clinical features and outcome. These findings underlines the necessity to rethink echocardiographic evaluation of SCD patients, with an integrative approach based on simultaneous evaluation of TRV along with left cavities remodeling and diastolic parameters.

Abstract Figure.
Reduction of left atrial strain and strain rate during conduit phase as the earliest marker of left ventricular diastolic disfunction
Authors: Savelev A , Solovev OV , Baturova MA , Shubik YV
Published: February 2021

Funding Acknowledgements

Type of funding sources: None.

Left atrial (LA) functional abnormalities, including LA strain (LAS) and strain rate (LASR) reduction, are observed in patients with left ventricular diastolic disfunction (LVDD). However, the degree of reduction at different stages of LVDD is not fully clarified.

We aimed to assess the interdependence between LAS and LASR parameters and LVDD grades in subjects of advanced age with preserved ejection fraction (EF).

Material and methods

Consecutive patients, who underwent echocardiography within 12 months, were screened and included into the study in case of age older than 65 years, preserved EF, sinus rhythm at the time of study and preserved dataset of sufficient quality for speckle tracking analysis. LAS and LASR parameters, including LAS and peak LASR during reservoir, conduit, and contractile phases were calulated with single plane apical 4-chamber view assessment. One-way ANOVA analysis with Bonferroni correction was used to assess the difference between groups.

Results

Among 153 patients (mean age 74 ± 7 years; 105 female, mean EF 64 ± 5%) included in the study there were 38 patients with no evidence of LVDD, 67 with LVDD grade 1, 40 with LVDD grade 2, and 5 with LVDD grade 3. The values of LAS and LASR parameters for these groups are summarized in Table. All parameters were significantly reduced in grade 2 and 3 LVDD patients comparing to the patients with no LVDD. Contractile phase LAS and LASR were slightly higher in grade 1 than in no LVDD patients. Reservoir and conduit phase LAS and LASR were lower in grade 1 LVDD comparing to no LVDD, but only for conduit phase parameters the difference was significant. In ROC analysis for conduit phase LAS and LASR to be associated with the presence of LVDD of any grade the  area under the curve was 0,707 (p < 0.001) and 0,742 (p < 0.001) respectively.

Conclusion

Impaired LA function is seen in patients with LVDD. Whereas measurements characterizing LA reservoir and contractile functions demonstrate significant decrease at advanced stages of LVDD, conduit function is significantly reduced at grade 1 LVDD, providing the possibility for early detection of LVDD.

Group LAS (%) LASR (1/sec) reservoir conduit contractile reservoir conduit contractile No LVDD, n = 38 29,7 ± 9,3 †‡ 15,1 ± 6,6 §†‡ 14,6 ± 5,4 †‡ 1,28 ± 0,37 †‡ 1,18 ± 0,44 §† 1,68 ± 0,60 †‡ Grade 1, n = 69 28,6 ± 8,9 †‡ 11,6 ± 6,2 ƒ 17,0 ± 5,7 †‡ 1,23 ± 0,43 ‡ 0,90 ± 0,38 ƒ 1,99 ± 0,71 †‡ Grade 2, n = 40 19,1 ± 7,1 ƒ§ 9,2 ± 4,5 ƒ 9,9 ± 4,4 ƒ§ 0,87 ± 0,26 ƒ§ 0,72 ± 0,27 ƒ 1,07 ± 0,44 ƒ§ Garde 3, n = 5 13,8 ± 3,6 ƒ§ 7,7 ± 2,5 ƒ 6,1 ± 2,2 ƒ§ 0,8 ± 0,29 ƒ 0,75 ± 0,28 0,67 ± 0,27 ƒ§ Significant difference (p < 0,05): ƒ – with No LVDD, § – with Grade 1 LVDD, † – with Grade 2 LVDD, ‡ – with Grade 3 LVDD
Prognostic role of myocardial work in patients with heart failure and reduced ejection fraction treated by sacubitril/valsartan
Authors: Galli E , Bouali Y , Gallard A , Hubert A , Leclercq C , Donal E
Published: February 2021

Funding Acknowledgements

Type of funding sources: None.

Background

the non-invasive assessment of myocardial work (MW) by pressure-strain loops analysis (PSL) is a relative new tool for the evaluation of myocardial performance. Sacubitril/Valsartan is a treatment for heart failure with reduced ejection fraction (HFrEF) which has a spectacular effect on the reduction of cardiovascular events (MACEs).

Purposes of this study were to evaluate 1) the short and medium term effect of Sacubitril/Valsartan treatment on MW parameters; 2) the prognostic value of MW in this specific group of patients.

Methods

79 patients with HFrEF (mean age: 66 ± 12 years; LV ejection fraction: 28 ± 9%) were prospectively included in the study and treated with Sacubitril/Valsartan. Echocardiographic examination was performed at baseline, and after 6- and 12-month of therapy with Sacubitril/Valsartan.

Results

Sacubitril/Valsartan significantly increased myocardial constructive work (CW) (1023 ± 449 vs 1424 ± 484 mmHg%, p < 0.0001) and myocardial work efficiency (WE) [87 (78-90) vs 90 (86-95), p < 0.0001]. During FU (2.6 ± 0.9 years), MACEs occurred in 13 (16%) patients. After correction for LV size, LVEF and WE, global myocardial constructive work (CW) was the only predictor of MACEs [HR 0.99 (0.99-1.00), p = 0.05]. (Table 1). A CW < 910 mmHg (AUC = 0.81, p < 0.0001, Figure 1, left panel) identified patients at particularly increase risk of MACEs [HR 11.09 (1.45-98.94), p = 0.002, log-rank test p < 0.0001] (Figure 2, Right panel).

Conclusions

in patients with HFrEF who receive a comprehensive background beta-blocker and mineral-corticoid receptor antagonist therapy, Sacubitril/Valsartan induces a significant improvement of myocardial CW and WE. In this population, the estimation of CW before the initiation of Sacubitril/Valsartan therapy allows the prediction of MACEs.

Univariable analysis Multivariable analysis HR (95% CI) p-value HR (95% CI) p-value Age, per year 0.99 (0.95-1.04) 0.81 Ischemic cardiomyopathy 1.07 (0.36-3.21) 0.89 LVEDVi*, per ml/m2 1.01 (1.00-1.03) 0.03 LVESVi, per ml/m2 1.01 (1.00-1.03) 0.009 1.01 (0.99-1.02) 0.35 LVEF, per % 0.91 (0.85-0.98) 0.01 1.02 (0.93-1.12) 0.71 CW, per mmHg% 0.99 (0.99-1.00) 0.002 0.99 (0.99-1.00) 0.04 WE, per mmHg% 0.91 (0.86-0.96) 0.001 0.95 (0.88-1.02) 0.16 Predictors of MACEs at univariable and multivariable analysis Abstract Figure 1 A and B