bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical simulation of coal wall cutting and lump coal formation in a fully mechanized mining face
Authors: Yuan Yong , Wang Shengzhi , Wang Wenmiao , Zhu Cheng
Published: January 2021

It is difficult to accurately calculate the lump coal rate in a fully mechanized mining face. Therefore, a numerical simulation of the coal wall cutting process, which revealed the crack expansion, development, evolution in the coal body and the corresponding lump coal formation mechanism, was performed in PFC2D. Moreover, a correlation was established between the cutting force and lump coal formation, and a statistical analysis method was proposed to determine the lump coal rate. The following conclusions are drawn from the results: (1) Based on a soft ball model, a coal wall cutting model is established. By setting the roller parameters based on linear bonding and simulating the roller cutting process of the coal body, the coal wall cutting process is effectively simulated, and accurate lump coal rate statistics are provided. (2) Under the cutting stress, the coal body in the working face underwent three stages—microfracture generation, fracture expansion, and fracture penetration—to form lump coal, in which the fracture direction is orthogonal to the cutting pressure chain. Within a certain range from the roller, as the cutting depth of the roller increased, the number of new fractures in the coal body first increases and then stabilizes. (3) Under the cutting stress, the fractured coal body is locally compressed, thereby forming a compact core. The formation and destruction of the compact core causes fluctuations in the cutting force. The fluctuation amplitude is positively related to the coal mass. (4) Because the simulation does not consider secondary damage in the coal, the simulated lump coal rate is larger than the actual lump coal rate in the working face; this deviation is mainly concentrated in large lump coal with a diameter greater than 300 mm.
Religious education for ecological sustainability: an initial reality check using the example of everyday decision-making
Authors: Altmeyer Stefan
Published: January 2021

There is a widely accepted consensus that religious education, together with all other school subjects, should contribute to the goals of education for sustainable development. As a result, theoretical models have been developed to profile what the specific contributions of religious education might be. However, the question whether religious education can achieve the intended goals has not yet been researched in more detail. More fundamentally, to be able to formulate realistic goals involves the clarification of students’ predispositions. In the light of these questions, the author focuses on an ecological sustainability dilemma, the so-called poplar dilemma, and asks how students react to this conflictive situation and what roles religious orientations play in their responses. Analysis of the responses of a sample of more than 1100, 14- to 16-year-old students at secondary schools in Germany and Austria led to the conclusion that over-reaching, action-changing environmental sustainability goals are probably beyond the reach of religious education as a single subject. Nevertheless, it becomes clear that ecological issues are regarded by many as religious and spiritual questions and can therefore be addressed in a focused way through religious education. The idea of religious stewardship, which implies taking responsibility and addresses both religious and non-religious students, could be particularly promising. Religious education could develop a characteristic profile as an area in which translation between different motivations for engaging in religious stewardship occurs, and where commitments to taking responsibility are sought.
Towards Post-Pandemic Sustainable and Ethical Food Systems
Authors: Kaiser Matthias , Goldson Stephen , Buklijas Tatjana , Gluckman Peter , Allen Kristiann , Bardsley Anne , Lam Mimi E.
Published: January 2021

The current global COVID-19 pandemic has led to a deep and multidimensional crisis across all sectors of society. As countries contemplate their mobility and social-distancing policy restrictions, we have a unique opportunity to re-imagine the deliberative frameworks and value priorities in our food systems. Pre-pandemic food systems at global, national, regional and local scales already needed revision to chart a common vision for sustainable and ethical food futures. Re-orientation is also needed by the relevant sciences, traditionally siloed in their disciplines and without adequate attention paid to how the food system problem is variously framed by diverse stakeholders according to their values. From the transdisciplinary perspective of food ethics, we argue that a post-pandemic scheme focused on bottom-up, regional, cross-sectoral and non-partisan deliberation may provide the re-orientation and benchmarks needed for not only more sustainable, but also more ethical food futures.
Impact of MTA blend % in melt spinning process and polyester properties
Authors: Rao Puli Nageswar , Sabavath G. K. , Paul S. N.
Published: January 2021

In Polyethylene terephthalate (PET) processing the raw materials are purified terephthalic acid (PTA), moderately purified terephthalic acid (MTA), monoehalene glycol (MEG). The processing of PTA is very difficult and costly. For reducing PTA percent we are using different percentages of MTA blend in PET processing. MTA affected the properties of polyester and melt spinning process. The properties such as elongation, tenacity, molecular chain length, b-color and IV, thermal properties, % carboxyl groups will change with MTA percentage. MTA percentage also affects fiber breakage percentage s, the melting point of PET. FTIR results show a change in chemical composition. Particle size, 4-CBA content of MTA affects the properties of the fiber.
Application of new series connection scheme of vortex tubes in seawater desalination unit using new vortex generators
Authors: Shmroukh Ahmed N. , Serageldin Ahmed A. , Abdal-hay Abdalla , Elreedy Ahmed , Radwan Ali
Published: January 2021

In this work, an experimental study on new series connection of two Ranque-Hilsch vortex tubes with new vortex generator materials, potential in seawater desalination was implemented, this combined modification has not been studied in open literature. Polycarbonate and Polyamide-Nylon 6 were tested and compared as new vortex generator materials that enhance the heat transfer between the two air streams inside the vortex tube. Moreover, using new seawater preheater by utilizing the waste heat in the exit air stream from the last vortex tube in the arrangement. The results revealed that the hot fraction of both arrangements should be kept at 0.5 for optimum vortex tubes series connection performance. Moreover, the modified series arrangement with Polycarbonate generator had higher evaporator main hot temperature and lower condenser main cold temperature than that of the modified series arrangement with Polyamide-Nylon 6 generator. Furthermore, the desalinated water percentage of Polycarbonate generator connection and Polyamide-Nylon 6 generator connection were reached about 94% and 89%, respectively. Therefore, the modified series hot connection of Ranque-Hilsch vortex tubes with Polycarbonate based vortex generator is recommended for use in seawater desalination applications.
Characterization and mapping of hematite ore mineral classes using hyperspectral remote sensing technique: a case study from Bailadila iron ore mining region
Authors: Shaik Ibrahim , Begum S. K. , Nagamani P. V. , Kayet Narayan
Published: January 2021

The study demonstrates a methodology for mapping various hematite ore classes based on their reflectance and absorption spectra, using Hyperion satellite imagery. Substantial validation is carried out, using the spectral feature fitting technique, with the field spectra measured over the Bailadila hill range in Chhattisgarh State in India. The results of the study showed a good correlation between the concentration of iron oxide with the depth of the near-infrared absorption feature (R2 = 0.843) and the width of the near-infrared absorption feature (R2 = 0.812) through different empirical models, with a root-mean-square error (RMSE) between < 0.317 and < 0.409. The overall accuracy of the study is 88.2% with a Kappa coefficient value of 0.81. Geochemical analysis and X-ray fluorescence (XRF) of field ore samples are performed to ensure different classes of hematite ore minerals. Results showed a high content of Fe > 60 wt% in most of the hematite ore samples, except banded hematite quartzite (BHQ) (< 47 wt%).
Petroleum pipeline monitoring using an internet of things (IoT) platform
Authors: Aba E. N. , Olugboji O. A. , Nasir A. , Olutoye M. A. , Adedipe O.
Published: January 2021

In this study, we present the use of an internet of things (IoT) analytics platform service to mimic real-time pipeline monitoring and determine the location of damage on a pipeline. Pressure pulses, based on the principle of vibration in pipes are used for pipeline monitoring in this study. The principle of time delay between pulse arrivals at sensor positions is also adopted in this study. An Arduino and a Wi-Fi module were combined, programmed and used to produce a wireless communication device which communicates with the ThingSpeak internet of things (IoT) analytics platform. A total of five channels were created on the platform to collect data from the five sensors that were used in the experimental test rig that made use of wireless communication device. Signal data was collected once every 15 s and all the channels were updated every 2 min. ThingSpeak provided instant visualizations of data posted by the wireless communication device. Online analysis and processing of the data was performed as it came in. A second test rig was built that made use of a data logger for processing of data. The measured velocity of pulse propagation using the data logger and air as transport fluid was 355 m/s. The computed estimates of event location for the 50 measurements taken ranged between 4.243 m and 4.246 m. This had a scatter of just 3 mm against the actual measured event location of 4.23 m. The experimental results obtained showed that the performance of the wireless communication device compared satisfactorily with the data logger and is capable of detecting the location of damage on real pipelines when used for real time monitoring.

Using this communication device and an analytics platform, real-time monitoring of pipelines can be carried out from any location in the world on any internet-enabled device.
Reducing enteric methane production from buffalo (Bubalus bubalis) by garlic oil supplementation in in vitro rumen fermentation system
Authors: Dey Avijit , Paul Shyam Sundar , Lailer Puran Chand , Dahiya Satbir Singh
Published: January 2021

Enteric methane production contributes significantly to the greenhouse gas emission globally. Although, buffaloes are integral part of livestock production in Asian countries, contributing milk, meat and draft power, the contribution of enteric methane to environmental pollution attracts attention. The present study investigated the efficacy of garlic (Allium sativum) oil in reducing enteric methane production from buffaloes (Bubalus bubalis) by in vitro rumen fermentation. Garlic oil (GOL) was tested at four concentrations [0 (Control), 33.33 µl (GOL-1), 83.33 µl (GOL-2) and 166.66 µl (GOL-3) per litre of buffered rumen fluid] in 100-ml graduated glass syringes and incubated at 39℃ for 24 h for in vitro rumen fermentation study. Supplementation of GOL-1 increased (p < 0.05) total gas production in comparison with GOL-3; however, it remained comparable (p > 0.05) with control and GOL-2. Graded doses of garlic oil inclusions reduced (p < 0.001) methane concentration (%) in total gas and total methane production (ml/g DM), irrespective of concentrations. The feed degradability, volatile fatty acids and microbial biomass production (MBP) were not affected (p > 0.05) by GOL-1, but these tended to decrease in GOL-2 with marked reduction (p < 0.01) in GOL-3. The decrease (p < 0.01) in NH3–N concentration in fermentation fluid in the presence of garlic oil, irrespective of concentration, suggests reduced deamination by inhibiting rumen proteolytic bacterial population. The activities of ruminal fibrolytic enzymes (CMCase, xylanase, β-glucosidase, acetyl esterase) were not affected by lower dose (GOL-1) of garlic oil; however, reduction (p < 0.05) of these enzymes activity in rumen liquor was evident at higher doses (GOL-2 and GOL-3) of supplementation. This study shows positive impact of garlic oil supplementation at low dose (33.33 µl/l of rumen fluid) in reducing enteric methane production, thereby, abatement of environmental pollution without affecting feed digestibility.
Human Anguish and God's Power
Authors: Kelsey David
Published: January 2021

Persons anguished by another's profound suffering are often outraged by well-intentioned efforts to console them which suggest that God 'sent' that horrific suffering to their loved one for a 'purpose' according to a tailor-made 'plan' for just that person. However, the outraged reaction simply deepens the anguish. This book argues that such 'consolation' is theologically problematic because it assumes that unrestricted power is what makes God 'God.' Against that it outlines an account of 'who' and 'what' the Triune God is, framed in terms of God's intrinsic 'glory,' the attractive and perfectly self-expressive self-giving in love that is God's life, and sets limits to the range of things we can say God 'does.' Correlatively it offers an account of different senses in which God is 'sovereign' and 'powerful', one which reflects three ways God relates to all else: to create, to bless eschatologically, and to reconcile, as is scripturally narrated.
Legal Encounters on the Medieval Globe
Authors: Symes Carol
Published: January 2021

Law has been a primary locus and vehicle of contact across human history - as a system of ideas embodied in people and enacted on bodies; and also as a material, textual, and sensory 'thing'. This volume analyzes a variety of legal encounters ranging from South Asia to South and Central America, Africa, the Middle East, and Europe. The seven essays also explore various material expressions of law that reveal the complexity and intensity of cross-cultural contact in this pivotal era.
Psychological Aspects of Geographical Moves
Authors: van Tilburg Miranda , Vingerhoets Ad J.J.M.
Published: January 2021

Mobility of mankind has increased enormously in the past few decades. People leave their homes and native countries for business and study, for vacation or to flee from unsafe conditions like wars and natural disasters. In all cases the sojourner faces a dual challenge of breaking with the familiar home environment and adjusting to new surroundings. This book deals with the psychological and health consequences of leaving the familiar home and the process of creating a new one. The focus is mainly on acculturation stress and homesickness, which both are relevant to those who travel. Acculturation refers to the process and outcome of a person's encounter with, and adaptation to, a culturally new and different environment. Homesickness is defined as a depression-like reaction to leaving one's home. The contributions in this book present empirical data as well as theoretical and conceptual discussions. Causes, consequences, moderating variables, and theoretical explanations are discussed. Both short-term (e.g., vacations) and long-term (e.g. immigration) separations from home receive attention. By combining these different but related topics, this book provides a valuable overview for researchers, teachers, students and professionals working with people who present with problems related to migration or traveling.
The Rise of the Cult of Rembrandt
Authors: McQueen Alison
Published: January 2021

Rembrandt's life and art had an almost mythic resonance in nineteenth-century France with artists, critics, and collectors alike using his artistic persona both as a benchmark and as justification for their own goals. This first in-depth study of the traditional critical reception of Rembrandt reveals the preoccupation with his perceived authenticity.
Eureka!
Authors: Breimer Douwe , Bremmer David , Provoost Frank , van Santen Hester , Weijts Christiaan
Published: January 2021

European universities currently face a dire financial crunch: governments throughout Europe are slashing their budgets for higher education, and fund-raising organizations are far less developed in European universities than in their American counterparts. €ureka! examines how European universities are rapidly adjusting to the situation, drawing on interviews with professionals and students from institutions in the League of European Research Universities. The contributors discuss ways in which European universities can raise funds and whether they will continue scholarly research or transform into research laboratories. €ureka! is a fascinating look at the state of higher education in a global context.
The European Repository Landscape
Authors: Graaf Maurits van der , Eijndhoven Kwame van
Published: January 2021

What is the current state of digital repositories for research output in the European Union? What should be the next steps to stimulate an infrastructure for digital repositories at a European level? To address these key questions, an inventory study into the current state of digital repositories for research output in the European Union was carried out as part of the DRIVER Project. The study produces a complete inventory of the state of digital repositories in the 27 countries of the European Union as per 2007 and provides a basis to contemplate the next steps in driving forward an interoperable infrastructure at a European level. This title is available in the OAPEN Library - http://www.oapen.org.
Armed Batavians
Authors: Nicolay Johan
Published: January 2021

Using a life-cycle model for Roman soldiers, Johan Nicolay interprets the large quantity of first-century finds as personal memorabilia brought home by ex-soldiers as a reminder of their twenty-five years of service and a symbol of their newly-acquired veteran status. Underpinning Nicolay's research is an extensive inventory of militaria from urban centers, rural settlements, rivers, and graves-presented in nearly one hundred individual color plates. Introducing a considerable body of unpublished data, as well as offering a perspective on daily life in the northern frontier of the Roman Empire, this volume is a valuable addition to Roman military and material history.
Spatial Characteristics of Recycled and Primordial Reservoirs in the Deep Mantle
Authors: Jackson M. G. , Becker T. W. , Steinberger B.
Published: January 2021

The spatial distribution of the geochemical domains hosting recycled crust and primordial (high‐3He/4He) reservoirs, and how they are linked to mantle convection, are poorly understood. Two continent‐sized seismic anomalies located near the core‐mantle boundary—called the Large Low Shear Wave Velocity Provinces (LLSVPs)—are potential geochemical reservoir hosts. It has been suggested that high‐3He/4He hotspots are spatially confined to the LLSVPs, hotspots sampling recycled continental crust are associated with only one of the LLSVPs, and recycled continental crust shows no relationship with latitude. We reevaluate the links between LLSVPs and isotopic signatures of hotspot lavas using improved mantle flow models including plume conduit advection. While most hotspots with the highest‐3He/4He can indeed be traced to the LLSVP interiors, at least one high‐3He/4He hotspot, Yellowstone, is located outside of the LLSVPs. This suggests high‐3He/4He is not geographically confined to the LLSVPs. Instead, a positive correlation between hotspot buoyancy flux and maximum hotspot 3He/4He suggests that it is plume dynamics (i.e., buoyancy), not geography, which determines whether a dense, deep, and possibly widespread high‐3He/4He reservoir is entrained. We also show that plume‐fed EM hotspots (enriched mantle, with low‐143Nd/144Nd), signaling recycled continental crust, are spatially linked to both LLSVPs, and located primarily in the southern hemisphere. Lastly, we confirm that hotspots sampling HIMU (“high‐μ,” or high 238U/204Pb) domains are not spatially limited to the LLSVPs. These findings clarify and advance our understanding of deep mantle reservoir distributions, and we discuss how continental and oceanic crust subduction is consistent with the spatial decoupling of EM and HIMU.
Species‐dependent Response of the Martian Ionosphere to the 2018 Global Dust Event
Authors: Niu D.‐D. , Cui J. , Wu S.‐Q. , Gu H. , Cao Y.‐T. , Wu Z.‐P. , Wu X.‐S. , Zhong J.‐H. , Wu M.‐Y. , Wei Y. , Zhang T.‐L.
Published: January 2021

Global dust storms (GDS) are an important dynamical phenomenon of the Martian lower atmosphere but are known to have important impacts on the Martian middle/upper atmosphere and ionosphere. Despite extensive studies over the past several decades, how the composition of the Martian ionosphere is modified during the GDS has only been studied from a theoretical point of view. Here we present for the first time the observations of the compositional variation of the Martian ionosphere during the GDS in 2018, using the ion density measurements made by the Neutral Gas and Ion Mass Spectrometer onboard the Mars Atmosphere and Volatile Evolution. At a representative altitude of 170 km, the variations of ionospheric species during the GDS show either enhancement (, Ar+, , H2O+, , ArH+) or depletion (, O+, /CO+, OH+). Despite the apparent diversity, the observations are mostly understandable within the established framework of ionospheric chemistry on Mars, which further demonstrates that the variation of ion species during the GDS is a good diagnostic of the variation of relevant neutral species in the thermosphere. In particular, the observed ionospheric variation strongly supports a scenario that H2O is substantially enhanced in the Martian thermosphere during the GDS. However, the variations of and are inconsistent with predictions from ionospheric chemistry and require further investigation.
Fuzzy Ensemble Clustering Approach to Address Regionalization Uncertainties in Flood Frequency Analysis
Authors: Kiran K. G. , Srinivas V. V.
Published: January 2021

Various regionalization approaches are in use to delineate watersheds in an area into homogeneous groups/regions for regional frequency analysis of hydrologic extremes (floods, droughts). Each approach differs in the underlying assumptions and strategy for regionalization and yields regions that differ in composition. There is ambiguity in the choice of approaches, as none is established to be universally superior in yielding true regions that are unknown. This article proposes a novel fuzzy ensemble clustering (FEC) approach to deal with uncertainty in the composition of regions obtained using different regionalization approaches. It forms fuzzy meta‐regions by integrating information on similarities in watershed groupings found in an ensemble of regions derived using several regionalization approaches. The FEC approach's potential to form effective regions (than those found in the ensemble) and their utility in regional flood frequency analysis to predict flood quantiles at ungauged sites is demonstrated through Monte Carlo simulation experiments and a case study on peninsular India. An ensemble of regions for use with FEC is formed using the region of influence approach, clustering approach based on Gaussian mixture model (GMM), and a hybrid approach which combines canonical correlation analysis with GMM based clustering. The FEC is shown to be effective in grouping similar watersheds even when the ensemble comprises regions having some improperly/wrongly grouped watersheds.
On-surface synthesis of graphene nanostructures with π-magnetism
Authors: Song Shaotang , Su Jie , Telychko Mykola , Li Jing , Li Guangwu , Li Ying , Su Chenliang , Wu Jishan , Lu Jiong
Published: January 2021

This review highlights the atomically-precise on-surface synthesis, topological and electronic structure characterization of open-shell graphene nanostructure, in combined with in-depth discussion on the mechanisms behind the π-magnetism.
Phase change mediated mechanically transformative dynamic gel for intelligent control of versatile devices
Authors: Zhao Xing , Peng Li-Mei , Chen Yi , Zha Xiang-Jun , Li Wu-Di , Bai Lu , Ke Kai , Bao Rui-Ying , Yang Ming-Bo , Yang Wei
Published: January 2021

A phase change mediated mechanically transformative dynamic gel enables dramatic stiffness change under a heat stimulus for intelligent control of versatile devices.
Research and application of a non-noble metal catalyst in the removal of trace olefins from aromatics
Authors: Wang Le , Meng Xuan , Wang Sitan , Shi Li , Hu Xiude , Liu Naiwang
Published: January 2021

Cu/ZnO/montmorillonite is a high-performance catalyst in the removal of trace olefins from aromatics.
Directed design of hydrogenation Ziegler systems
Authors: Titova Yuliya Yu. , Schmidt Fedor K.
Published: January 2021

We reported the concept of a directed design of multicomponent catalytic systems of the hydrogenation of unsaturated hydrocarbons.
Bioinspired surfaces with special micro-structures and wettability for drag reduction: which surface design will be a better choice?
Authors: Zhu Yi , Yang Fuchao , Guo Zhiguang
Published: January 2021

Human beings learn from creatures in nature and imitate them to solve drag reduction challenges in daily life.
Unravelling the potency of triazole analogues for inhibiting α-synuclein fibrillogenesis andin vitrodisaggregation
Authors: Maqbool Mudasir , Gadhavi Joshna , Singh Anju , Hivare Pravin , Gupta Sharad , Hoda Nasimul
Published: January 2021

Triazole-based compounds as inhibitors and disaggregators of α-synuclein.
8-Aminoimidazo[1,2-a]pyridine (AIP) directed Pd(ii) catalysis: site-selective ortho-C(sp2)–H arylation in aqueous medium
Authors: Mondal Biswajit , Ghosh Prasanjit , Kundu MrinalKanti , Das Sajal
Published: January 2021

An efficient and facile Pd(ii) catalyzed selective ortho and β-C(sp2)–H arylation reaction employing the 8-AIP (aminoimidazo[1,2-a]pyridine) auxiliary as a removable N,N-bidentate directing group in a green solvent (water) has been reported.
Pairing Suzuki–Miyaura cross-coupling and catalyst transfer polymerization
Authors: Bautista Michael V. , Varni Anthony J. , Ayuso-Carrillo Josué , Carson Matthew C. , Noonan Kevin J. T.
Published: January 2021

Borylation strategies to make AB Suzuki–Miyaura monomers for use in catalyst-transfer polymerization with nickel or palladium catalysts.
Development of pre-service teachers’ pedagogical content knowledge through a PCK-based school experience course
Authors: Ekiz-Kiran Betul , Boz Yezdan , Oztay Elif Selcan
Published: January 2021

The purpose of this study was to improve the pedagogical content knowledge (PCK) of pre-service chemistry teachers using a school experience course enriched with PCK development tools such as CoRe as a lesson planning form, observations of mentor teachers’ teaching by using an observation form prepared based on PCK components, discussion sessions on these observations, and reflections on their teaching. Some valuable results of the study indicated that pre-service teachers' science teaching orientations did not change during the study. However, all participants' knowledge of learners and knowledge of instructional strategies improved by the end of the study. Knowledge of curriculum and knowledge of assessment are the components of PCK in which some pre-service teachers showed no improvement.
Students’ meaningful learning experiences from participating in organic chemistry writing-to-learn activities
Authors: Gupte Trisha , Watts Field M. , Schmidt-McCormack Jennifer A. , Zaimi Ina , Gere Anne Ruggles , Shultz Ginger V.
Published: January 2021

Teaching organic chemistry requires supporting learning strategies that meaningfully engage students with the challenging concepts and advanced problem-solving skills needed to be successful. Such meaningful learning experiences should encourage students to actively choose to incorporate new concepts into their existing knowledge frameworks by appealing to the cognitive, affective, and psychomotor domains of learning. This study provides a qualitative analysis of students’ meaningful learning experiences after completing three Writing-to-Learn (WTL) assignments in an organic chemistry laboratory course. The assignments were designed to appeal to the three domains necessary for a meaningful learning experience, and this research seeks to understand if and how the WTL assignments promoted students’ meaningful learning. The primary data collected were the students’ responses to open-ended feedback surveys conducted after each assignment. These responses were qualitatively analyzed to identify themes across students’ experiences about their meaningful learning. The feedback survey analysis was triangulated with interviews conducted after each assignment. The results identify how the assignments connected to students’ existing knowledge from other courses and indicate that assignment components such as authentic contexts, clear expectations, and peer review supported students’ meaningful learning experiences. These results inform how assignment design can influence students’ learning experiences and suggest implications for how to support students’ meaningful learning of organic chemistry through writing.
Retrosynthetic accessibility score (RAscore) – rapid machine learned synthesizability classification from AI driven retrosynthetic planning
Authors: Thakkar Amol , Chadimová Veronika , Bjerrum Esben Jannik , Engkvist Ola , Reymond Jean-Louis
Published: January 2021

The retrosynthetic accessibility score (RAscore) is based on AI driven retrosynthetic planning, and is useful for rapid scoring of synthetic feasability and pre-screening of large datasets of virtual/generated molecules.
Copper-based single-atom alloys for heterogeneous catalysis
Authors: Qin Fengjuan , Chen Wenxing
Published: January 2021

Compared with traditional catalysts, copper-based SAAs have high activity and stability in heterogeneous catalysis due to their special structures and interactions.
Hyperglycemia at admission is a strong predictor of mortality and severe/critical complications in COVID-19 patients: a meta-analysis
Authors: Yang Yan , Cai Zixin , Zhang Jingjing
Published: January 2021

Background: Hyperglycemia at admission has been demonstrated to exacerbate the outcomes of coronavirus disease 2019 (COVID-19) but a meta-analysis is lacking to further confirm this hypothesis. The purpose of this meta-analysis was to summarize the evidence on the association between hyperglycemia at admission and the development of COVID-19. Method: Four databases namely, PubMed, Web of Science, Embase and Cochrane Library, were screened for eligible studies. STATA software was utilized to pool data for this meta-analysis. The primary outcomes included mortality and severity. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated with random-effects models, and the quality of evidence was appraised by the Newcastle–Ottawa Scale (NOS). This meta-analysis was prospectively registered online on PROSPERO, CRD42020191763. Results: Sixteen observational studies with 6386 COVID-19 patients relating hyperglycemia at admission to COVID-19 outcomes were included. The overall data demonstrated that, compared with the control, the hyperglycemia at admission group was more likely to have increased mortality (OR = 3.45, 95% CI, 2.26–5.26) and severe/critical complications (OR = 2.08, 95% CI, 1.45–2.99) of COVID-19. Conclusion: Hyperglycemia at admission in COVID-19 patients may be a strong predictor of mortality and complications.
Acid sphingomyelinase promotes SGK1-dependent vascular calcification
Authors: Luong Trang Thi Doan , Tuffaha Rashad , Schuchardt Mirjam , Moser Barbara , Schelski Nadeshda , Boehme Beate , Gollmann-Tepeköylü Can , Schramm Clara , Holfeld Johannes , Pieske Burkert , Gulbins Erich , Tölle Markus , van der Giet Markus , Lang Florian , Eckardt Kai-Uwe , Voelkl Jakob , Alesutan Ioana
Published: January 2021

In chronic kidney disease (CKD), hyperphosphatemia is a key factor promoting medial vascular calcification, a common complication associated with cardiovascular events and high mortality. Vascular calcification involves osteo-/chondrogenic transdifferentiation of vascular smooth muscle cells (VSMCs), but the complex signaling events inducing pro-calcific pathways are incompletely understood. The present study investigated the role of acid sphingomyelinase (ASM)/ceramide as regulator of VSMC calcification. In vitro, both, bacterial sphingomyelinase and phosphate increased ceramide levels in VSMCs. Bacterial sphingomyelinase as well as ceramide supplementation stimulated osteo-/chondrogenic transdifferentiation during control and high phosphate conditions and augmented phosphate-induced calcification of VSMCs. Silencing of serum- and glucocorticoid-inducible kinase 1 (SGK1) blunted the pro-calcific effects of bacterial sphingomyelinase or ceramide. Asm deficiency blunted vascular calcification in a cholecalciferol-overload mouse model and ex vivo isolated-perfused arteries. In addition, Asm deficiency suppressed phosphate-induced osteo-/chondrogenic signaling and calcification of cultured VSMCs. Treatment with the functional ASM inhibitors amitriptyline or fendiline strongly blunted pro-calcific signaling pathways in vitro and in vivo. In conclusion, ASM/ceramide is a critical upstream regulator of vascular calcification, at least partly, through SGK1-dependent signaling. Thus, ASM inhibition by repurposing functional ASM inhibitors to reduce the progression of vascular calcification during CKD warrants further study.
β-blockade prevents coronary macro- and microvascular dysfunction induced by a high salt diet and insulin resistance in the Goto–Kakizaki rat
Authors: Pearson James T. , Thambyah Hamish P. , Waddingham Mark T. , Inagaki Tadakatsu , Sukumaran Vijayakumar , Ngo Jennifer P. , Ow Connie P.C. , Sonobe Takashi , Chen Yi Ching , Edgley Amanda J. , Fujii Yutaka , Du Cheng-Kun , Zhan Dong-Yun , Umetani Keiji , Kelly Darren J. , Tsuchimochi Hirotsugu , Shirai Mikiyasu
Published: January 2021

A high salt intake exacerbates insulin resistance, evoking hypertension due to systemic perivascular inflammation, oxidative-nitrosative stress and endothelial dysfunction. Angiotensin-converting enzyme inhibitor (ACEi) and angiotensin receptor blockers (ARBs) have been shown to abolish inflammation and redox stress but only partially restore endothelial function in mesenteric vessels. We investigated whether sympatho-adrenal overactivation evokes coronary vascular dysfunction when a high salt intake is combined with insulin resistance in male Goto–Kakizaki (GK) and Wistar rats treated with two different classes of β-blocker or vehicle, utilising synchrotron-based microangiography in vivo. Further, we examined if chronic carvedilol (CAR) treatment preserves nitric oxide (NO)-mediated coronary dilation more than metoprolol (MET). A high salt diet (6% NaCl w/w) exacerbated coronary microvessel endothelial dysfunction and NO-resistance in vehicle-treated GK rats while Wistar rats showed modest impairment. Microvascular dysfunction was associated with elevated expression of myocardial endothelin, inducible NO synthase (NOS) protein and 3-nitrotyrosine (3-NT). Both CAR and MET reduced basal coronary perfusion but restored microvessel endothelium-dependent and -independent dilation indicating a role for sympatho-adrenal overactivation in vehicle-treated rats. While MET treatment reduced myocardial nitrates, only MET treatment completely restored microvessel dilation to dobutamine (DOB) stimulation in the absence of NO and prostanoids (combined inhibition), indicating that MET restored the coronary flow reserve attributable to endothelium-derived hyperpolarisation (EDH). In conclusion, sympatho-adrenal overactivation caused by high salt intake and insulin resistance evoked coronary microvessel endothelial dysfunction and diminished NO sensitivity, which were restored by MET and CAR treatment in spite of ongoing inflammation and oxidative-nitrosative stress presumably caused by uninhibited renin–angiotensin–aldosterone system (RAAS) overactivation.
Experimental data using candesartan and captopril indicate no double-edged sword effect in COVID-19
Authors: Pedrosa Maria A. , Valenzuela Rita , Garrido-Gil Pablo , Labandeira Carmen M. , Navarro Gemma , Franco Rafael , Labandeira-Garcia Jose L. , Rodriguez-Perez Ana I.
Published: January 2021

The key link between renin–angiotensin system (RAS) and COVID-19 is ACE2 (angiotensin-converting enzyme 2), which acts as a double-edged sword, because ACE2 increases the tissue anti-inflammatory response but it is also the entry receptor for the virus. There is an important controversy on several drugs that regulate RAS activity and possibly ACE2, and are widely used, particularly by patients most vulnerable to severe COVID-19. In the lung of healthy rats, we observed that candesartan (an angiotensin type-1, AT1, receptor blocker; ARB) and captopril (an ACE inhibitor; ACEI) up-regulated expression of tissue ACE2 and RAS anti-inflammatory axis receptors (AT2 and Mas receptors). This effect was particularly pronounced in rats with metabolic syndrome (obesity, increased blood pressure and hyperglycemia) and aged rats. Treatment of cultures of human type-II pneumocytes with candesartan or captopril induced up-regulation of ACE2 expression in cells. Treatment with viral spike protein induced a decrease in full-length (i.e. transmembrane) ACE2, an increase in levels of a short intracellular ACE2 polypeptide and an increase in ADAM17 activity in cells, together with an increase in levels of soluble ACE2 and major proinflammatory cytokines in the culture medium. Spike protein-induced changes and levels of spike protein internalization in cells were inhibited by pretreatment with the above-mentioned drugs. The results suggest that these drugs increase ACE2 levels and promote the anti-inflammatory RAS axis in the lung. Furthermore, possible up-regulation of viral entry by the drug-induced increase in expression of transmembrane ACE2 is counteracted by additional mechanisms, particularly by drug-induced inhibition of ADAM17 activity.
Online multi‐parameter estimation of permanent magnet synchronous machine with step‐pulse injection
Authors: Wang Peng , Lin Keman , Lin Mingyao , Yang Anchen , Fu Fangyuan , Ai Jian
Published: January 2021

Online estimation of the machine parameters is essential to fault diagnosis and high‐performance control of permanent magnet synchronous machine (PMSM). The signal injection is an effective way to estimate machine parameters. However, the inductance variation caused by signal injection will result in difficulties for the estimated parameters to converge. At the same time, online parameters estimation brings heavy burden to the operation of control system. To solve these two problems, optimized inductance model is built with the step‐pulse injection to improve the accuracy of estimation. Compared with the existing method, the step‐by‐step parameter estimation method is adopted and orders of feedback matrix are reduced, which improves the computation efficiency. The forgetting factor recursive least square (FFRLS) algorithm is adopted to estimate stator resistance, rotor flux linkage and d‐, q‐axes inductances without acquiring any nominal parameter. The minimum amplitude and appropriate frequency of step‐pulse are determined by the parameter error and convergence analysis. The effectiveness of the proposed method is verified via a 1.5 kW PMSM drive platform.
Design of coaxial magnetic gear utilising a novel permanent magnet Halbach array structure
Authors: Mafi Hanieh , Afjei Ebrahim , Ghaheri Aghil
Published: January 2021

Mechanical gears are constrained due to wear and tear and call for lubrication. A magnetic gear, utilising permanent magnet (PM) arrays, facilitates the mechanical gear roles. It can withstand high‐speeds and large loads with zero friction. The magnetic gear is more efficacious on account of the least noise, performance, overload protection, and physical isolation between parts than conventional mechanical gears. The quantity of PMs in magnetic structures plays a principal role in its total price, which necessitates optimal arrangements for PMs. Halbach array provides a bigger torque density according to its one‐sided flux. In this research, proposing a novel Halbach array structure, leads to intensification in the one‐sided flux in a much sinusoidally waveform that consequently increases the magnetic torque. These all lead to gain higher torques in constant volumes of magnets. Besides, the magnetic torque ripple and the modulators’ losses are decremented. The new model is based on the variation of the magnetisation angles of the adjacent permanent magnet blocks, in the array. Various states of the magnetisation angles in the array are optimised based on a heuristic method. This is studied in the whole trigonometric range for magnetisation angles characteristics. The prototype is fabricated based on the optimised magnetic gear design and complies with the results.
Comparison of rare‐earth and hybrid‐magnet mover configurations for a permanent magnet synchronous linear motor
Authors: Liu Xiaomei , Yu Haitao , Gerada David , Xu Zeyuan , Qiu Hongbo , Jia Wanying , Yang Cunxiang
Published: January 2021

Force ripple and cost reduction are two of the main challenges in optimising the design and increasing the market uptake of permanent magnet synchronous linear motors (PMSLM). Two mover configurations are compared in depth; one made entirely from rare‐earth materials while another consisting of a hybrid (rare‐earth/ferrite) magnet layout. First, the rare‐earth PMSLM is optimised and designed. Based on the same design and simulation methods, a hybrid PM materials with structure PMSLM is then proposed, optimised and designed using NdFeB at the centre pole‐section and ferrite at the edges. The two configurations of the PMSLM and their relative merits/demerits are compared using the simulation results of the flux density distribution in the air gap, back electromotive force (EMF), and cogging force. The hybrid‐magnet structure PMLSM has a better magnetic performance, and the force ripple is reduced by around 1%. Furthermore, the magnet material cost of the hybrid‐magnet PMLSM is reduced by nearly 25% compared with the original PMLSM. Finally, a prototype of the rare‐earth and hybrid‐magnet PMSLM is manufactured and tested to validate the modelling techniques and the results.
A fast level set image segmentation driven by a new region descriptor
Authors: Birane Abdelkader , Hamami Latifa
Published: January 2021

In order to deal with the intensities inhomogeneities and to overcome the effect of different types of noise in the image segmentation process, we have formulated a new level set function to implement a fast and robust active contour model. The proposed model was formulated by combining the SBGFRLS model and Legendre polynomials. With the aim of ensuring the segmentation accuracy and for dealing in the best way with the presence of noises and inhomogenous distribution of intensity, we define a local region descriptor for image intensities based on the Legendre polynomial. Instead of using the average intensity of the region, we regularised our level set function using a Gaussian filtering process. Experimental results on challenging images demonstrate the efficiency, robustness and the low cost and computational time of our model against the well‐known active contour models.
Colour image segmentation based on a convex K‐means approach
Authors: Wu Tingting , Gu Xiaoyu , Shao Jinbo , Zhou Ruoxuan , Li Zhi
Published: January 2021

Image segmentation is a fundamental and challenging task in image processing and computer vision. The colour image segmentation is attracting more attention as the colour image provides more information than the grey image. A variational model based on a convex K‐means approach to segment colour images is proposed. The proposed variational method uses a combination of l1 and l2 regularizers to maintain edge information of objects in images while overcoming the staircase effect. Meanwhile, our one‐stage strategy is an improved version based on the smoothing and thresholding strategy, which contributes to improving the accuracy of segmentation. The proposed method performs the following steps. First, the colour set which can be determined by human or the K‐means method is specified. Second, a variational model to obtain the most appropriate colour for each pixel from the colour set via convex relaxation and lifting is used. The Chambolle–Pock algorithm and simplex projection are applied to solve the variational model effectively. Experimental results and comparison analysis demonstrate the effectiveness and robustness of the method.
General polynomial chaos‐based expansion finite‐difference time‐domain method for analysing electromagnetic wave propagation in random dispersive media
Authors: Liu Jiangfan , Li Huiping , Xi Xiaoli
Published: January 2021

A new approach for using polynomial chaos‐based expansion finite‐difference time‐domain (PCE‐FDTD) is presented to calculate the uncertainty of electromagnetic wave propagation in dispersive materials. Based on the bilinear transform method, this approach performs polynomial expansion on random electromagnetic fields by PCE‐FDTD method. The proposed algorithm has a simple formulation and is very easy to extend to isotropic dispersive material. It has a general form for different types of random dispersive materials and can efficiently calculate the mean value and the SD of electromagnetic field components in a single run. Two examples of different dispersive media with two random variables are listed to show the generality of the algorithm, and a radar cross‐section of a perfectly conducting cylinder coated by a layer of random plasma is illustrated as an example to show the practicability of the approach. The results are validated by comparing it with the Monte Carlo method.
Symptomkontrolle bei Herzinsuffizienzpatienten – was tun bei abfallender GFR und bei Hyperkaliämie?
Authors: Brandenburg Vincent , Bauersachs Johann , Böhm Michael , Fliser Danilo , Frantz Stefan , Frey Norbert , Hasenfuß Gerd , Kielstein Jan T.
Published: January 2021

Bei Patienten mit Herzinsuffizienz und reduzierter Ejektionsfraktion wird durch eine optimierte medikamentöse Therapie sowohl die Symptomkontrolle verbessert als auch die Mortalität gesenkt. Eckpfeiler der Herzinsuffizienztherapie sind dabei Medikamente mit Einfluss auf das Renin-Angiotensin-Aldosteron-System, sogenannte RAAS-Inhibitoren. Dieser Artikel stellt einen kardiologisch-nephrologischen Konsens zur praxisorientierten Hilfestellung bei abnehmender glomerulärer Filtrationsrate oder Anstieg des Serum-Kaliumspiegels vor. Dies sind die 2 häufigsten Gründe für eine Dosisreduktion oder das Absetzen von prognoseverbessernden Medikamenten bei Herzinsuffizienzpatienten.
Permanent External Biliary Catheter: A Difficult Problem Managed by Rescue Technique of Hepatico-cholecysto-gastrostomy
Authors: Singla Vikas , Yadav Ajit Kumar , Arora Anil , Gupta Arun
Published: January 2021

Percutaneous biliary drainage is commonly performed procedure after failure of ERCP in patients with biliary obstruction. Failure to internalization can lead to permanent external catheter. In the present case, problem of external biliary catheter was solved with hepaticocholecystogastrostomy. Guidewire from the external drain site could not be passed across the stricture, instead it was entering in the gall bladder. This was used as an opportunity to internalize the catheter. First EUS guided cholecystogastrostomy was performed, followed by placement of stent between right biliary system and the stomach, through the cholecystogastrostomy stent. This led to drainage of right biliary system into the stomach, and the external catheter could be removed.