bluuebunny/crossref_metadata_2025 huggingface dataset:
On the preservation of vessel bifurcations during flow-mediated angiogenic remodelling
Authors: Edgar Lowell T. , Franco Claudio A. , Gerhardt Holger , Bernabeu Miguel O.
Published: February 2021

During developmental angiogenesis, endothelial cells respond to shear stress by migrating and remodelling the initially hyperbranched plexus, removing certain vessels whilst maintaining others. In this study, we argue that the key regulator of vessel preservation is cell decision behaviour at bifurcations. At flow-convergent bifurcations where migration paths diverge, cells must finely tune migration along both possible paths if the bifurcation is to persist. Experiments have demonstrated that disrupting the cells’ ability to sense shear or the junction forces transmitted between cells impacts the preservation of bifurcations during the remodelling process. However, how these migratory cues integrate during cell decision making remains poorly understood. Therefore, we present the first agent-based model of endothelial cell flow-mediated migration suitable for interrogating the mechanisms behind bifurcation stability. The model simulates flow in a bifurcated vessel network composed of agents representing endothelial cells arranged into a lumen which migrate against flow. Upon approaching a bifurcation where more than one migration path exists, agents refer to a stochastic bifurcation rule which models the decision cells make as a combination of flow-based and collective-based migratory cues. With this rule, cells favour branches with relatively larger shear stress or cell number. We found that cells must integrate both cues nearly equally to maximise bifurcation stability. In simulations with stable bifurcations, we found competitive oscillations between flow and collective cues, and simulations that lost the bifurcation were unable to maintain these oscillations. The competition between these two cues is haemodynamic in origin, and demonstrates that a natural defence against bifurcation loss during remodelling exists: as vessel lumens narrow due to cell efflux, resistance to flow and shear stress increases, attracting new cells to enter and rescue the vessel from regression. Our work provides theoretical insight into the role of junction force transmission has in stabilising vasculature during remodelling and as an emergent mechanism to avoid functional shunting.
Reproduction of patterns in melanocytic proliferations by agent-based simulation and geometric modeling
Authors: Schneckenreither Günter , Tschandl Philipp , Rippinger Claire , Sinz Christoph , Brunmeir Dominik , Popper Nikolas , Kittler Harald
Published: February 2021

Spatio-temporal patterns of melanocytic proliferations observed in vivo are important for diagnosis but the mechanisms that produce them are poorly understood. Here we present an agent-based model for simulating the emergence of the main biologic patterns found in melanocytic proliferations. Our model portrays the extracellular matrix of the dermo-epidermal junction as a two-dimensional manifold and we simulate cellular migration in terms of geometric translations driven by adhesive, repulsive and random forces. Abstracted cellular functions and melanocyte-matrix interactions are modeled as stochastic events. For identification and validation we use visual renderings of simulated cell populations in a horizontal perspective that reproduce growth patterns observed in vivo by sequential dermatoscopy and corresponding vertical views that reproduce the arrangement of melanocytes observed in histopathologic sections. Our results show that a balanced interplay of proliferation and migration produces the typical reticular pattern of nevi, whereas the globular pattern involves additional cellular mechanisms. We further demonstrate that slight variations in the three basic cellular properties proliferation, migration, and adhesion are sufficient to produce a large variety of morphological appearances of nevi. We anticipate our model to be a starting point for the reproduction of more complex scenarios that will help to establish functional connections between abstracted microscopic behavior and macroscopic patterns in all types of melanocytic proliferations including melanoma.
Multiple sensors provide spatiotemporal oxygen regulation of gene expression in a Rhizobium-legume symbiosis
Authors: Rutten Paul J. , Steel Harrison , Hood Graham A. , Ramachandran Vinoy K. , McMurtry Lucie , Geddes Barney , Papachristodoulou Antonis , Poole Philip S.
Published: February 2021

Regulation by oxygen (O2) in rhizobia is essential for their symbioses with plants and involves multiple O2 sensing proteins. Three sensors exist in the pea microsymbiont Rhizobium leguminosarum Rlv3841: hFixL, FnrN and NifA. At low O2 concentrations (1%) hFixL signals via FxkR to induce expression of the FixK transcription factor, which activates transcription of downstream genes. These include fixNOQP, encoding the high-affinity cbb3-type terminal oxidase used in symbiosis. In free-living Rlv3841, the hFixL-FxkR-FixK pathway was active at 1% O2, and confocal microscopy showed hFixL-FxkR-FixK activity in the earliest stages of Rlv3841 differentiation in nodules (zones I and II). Work on Rlv3841 inside and outside nodules showed that the hFixL-FxkR-FixK pathway also induces transcription of fnrN at 1% O2 and in the earliest stages of Rlv3841 differentiation in nodules. We confirmed past findings suggesting a role for FnrN in fixNOQP expression. However, unlike hFixL-FxkR-FixK, Rlv3841 FnrN was only active in the near-anaerobic zones III and IV of pea nodules. Quantification of fixNOQP expression in nodules showed this was driven primarily by FnrN, with minimal direct hFixL-FxkR-FixK induction. Thus, FnrN is key for full symbiotic expression of fixNOQP. Without FnrN, nitrogen fixation was reduced by 85% in Rlv3841, while eliminating hFixL only reduced fixation by 25%. The hFixL-FxkR-FixK pathway effectively primes the O2 response by increasing fnrN expression in early differentiation (zones I-II). In zone III of mature nodules, near-anaerobic conditions activate FnrN, which induces fixNOQP transcription to the level required for wild-type nitrogen fixation activity. Modelling and transcriptional analysis indicates that the different O2 sensitivities of hFixL and FnrN lead to a nuanced spatiotemporal pattern of gene regulation in different nodule zones in response to changing O2 concentration. Multi-sensor O2 regulation is prevalent in rhizobia, suggesting the fine-tuned control this enables is common and maximizes the effectiveness of the symbioses.
Assessing the reporting of Dengue, Chikungunya and Zika to the National Surveillance System in Colombia from 2014–2017: A Capture-recapture analysis accounting for misclassification of arboviral diagnostics
Authors: Carabali Mabel , Jaramillo-Ramirez Gloria I. , Rivera Vivian A. , Mina Possu Neila-Julieth , Restrepo Berta N. , Zinszer Kate
Published: February 2021

Background

Chikungunya, dengue, and Zika are three different arboviruses which have similar symptoms and are a major public health issue in Colombia. Despite the mandatory reporting of these arboviruses to the National Surveillance System in Colombia (SIVIGILA), it has been reported that the system captures less than 10% of diagnosed cases in some cities.

Methodology/Principal findings

To assess the scope and degree of arboviruses reporting in Colombia between 2014–2017, we conducted an observational study of surveillance data using the capture-recapture approach in three Colombian cities. Using healthcare facility registries (capture data) and surveillance-notified cases (recapture data), we estimated the degree of reporting by clinical diagnosis. We fit robust Poisson regressions to identify predictors of reporting and estimated the predicted probability of reporting by disease and year. To account for the potential misclassification of the clinical diagnosis, we used the simulation extrapolation for misclassification (MC-SIMEX) method. A total of 266,549 registries were examined. Overall arboviruses’ reporting ranged from 5.3% to 14.7% and varied in magnitude according to age and year of diagnosis. Dengue was the most notified disease (21–70%) followed by Zika (6–45%). The highest reporting rate was seen in 2016, an epidemic year. The MC-SIMEX corrected rates indicated underestimation of the reporting due to the potential misclassification bias.

Conclusions

These findings reflect challenges on arboviruses’ reporting, and therefore, potential challenges on the estimation of arboviral burden in Colombia and other endemic settings with similar surveillance systems.
Prevalence and evolutionary analyses of human T-cell lymphotropic virus in Guangdong province, China: Transcontinental and Japanese subtype lineages dominate the prevalence
Authors: Liao Qiao , Shan Zhengang , Wang Min , Huang Jieting , Xu Ru , Li Tingting , Wang Wenjing , Li Chengyao , Rong Xia , Fu Yongshui
Published: February 2021

To systematically characterize the prevalence and evolution of human T-cell lymphotropic virus (HTLV) infection among voluntary blood donors (BDs) in Guangdong province, China. A three-year survey for HTLV epidemiology among BDs was performed in Guangdong during 2016–2018. Anti-HTLV-1/2 was screened by ELISA and ECLIA, and subsequently confirmed by western blot (WB) and nucleic acid testing (NAT). The prevalence of HTLV in donors from different cities was calculated. The identified HTLV-positive cases were phylogenetically genotyped and analyzed in a Bayesian phylogenetic framework. Among 3,262,271 BDs, 59 were confirmed positive for HTLV-1 (1.81 per 100,000) and no HTLV-2 infection was found. The prevalence of HTLV-1 varied significantly among 21 cities in Guangdong province, China. The highest prevalence was found in donors from Shanwei (13.94 per 100,000), which is a coastal city in eastern Guangdong. Viral genomic sequences genotyped from 55 HTLV-1 carriers showed that 39 were transcontinental subtype and 16 were Japanese subtype. Specially, 13 out of 39 transcontinental subtype sequences were characterized with L55P mutation and 21 out of 55 sequences were characterized with L19F mutation in viral gp46 protein. The L55P mutation seemed be specific to eastern Asia since it only presented in the sequences from Japan, mainland China, and Taiwan. Phylogenetic analysis of gp46 gene shows that HTLV-1a may have been introduced to Guangdong through four different introduction events and formed major transmission clusters: clades I(13,602 years ago), II(16, 010 years ago), III(15,639 years ago) and IV(16,517 years ago). In general, Guangdong is considered to be a low-prevalence region for HTLV-1 infection, but the prevalence is significantly higher in Shanwei city. Transcontinental and Japanese subtype lineages dominate the prevalence in Guangdong. In terms of blood safety, HTLV antibody screening for first-time blood donors can effectively reduce the risk of HTLV transmission.
Comparison of the hemolysis machinery in two evolutionarily distant blood-feeding arthropod vectors of human diseases
Authors: Dorrah Moataza , Bensaoud Chaima , Mohamed Amr A. , Sojka Daniel , Bassal Taha T. M. , Kotsyfakis Michail
Published: February 2021

Host blood protein digestion plays a pivotal role in the ontogeny and reproduction of hematophagous vectors. The gut of hematophagous arthropods stores and slowly digests host blood and represents the primary gateway for transmitted pathogens. The initial step in blood degradation is induced lysis of host red blood cells (hemolysis), which releases hemoglobin for subsequent processing by digestive proteolytic enzymes. The activity cycles and characteristics of hemolysis in vectors are poorly understood. Hence, we investigated hemolysis in two evolutionarily distant blood-feeding arthropods: The mosquito Culex pipiens and the soft tick Argas persicus, both of which are important human and veterinary disease vectors. Hemolysis in both species was cyclical after blood meal ingestion. Maximum digestion occurs under slightly alkaline conditions in females. Hemolytic activity appears to be of lipoid origin in C. pipiens and enzymatic activity (proteolytic) in A. persicus. We have assessed the effect of pH, incubation time, and temperature on hemolytic activity and the hemolysin. The susceptibility of red blood cells from different hosts to the hemolysin and the effect of metabolic inhibition of hemolytic activity were assessed. We conclude that in C. pipiens and A. persicus midgut hemolysins control the amplitude of blood lysis step to guarantee an efficient blood digestion.
An Assessment of the Effect of Remuneration on the Construction Performances of the Professionals in the Nigerian Building Industry
Authors: Awoles J.A.B. , Ayedun C.A.
Published: February 2021

Construction professionals are the authors on one hand and co-executors of constructionprojects on the other, therefore, the quality of the services expected of them in constructionproject delivery as environmental resource manager is key. This paper investigated whetherquality of service of the construction professionals in Nigeria is influenced by the level ofprofessional fees receivable for services rendered hence their resource management role. Thedeterminants of service quality are identified and their means of evaluation examined usingthe SERVQUAL; instrument used for measurement of the service quality on responses gotfrom a set of questionnaires administered on the construction stakeholders comprising of theconstruction clients on one hand and the construction professionals on the other hand inLagos, Nigeria with a view to assessing the perception of the clients regarding the quality ofservices being received from their construction professionals vis-a-vis clients expectations.The study revealed that there was no significant relationship between the level of fees paidand the quality of service rendered by the construction professionals as the result of theanalysis of variance between service quality gap and the various methods of fees paid is notreflected in the service quality of construction professionals.
SOCIAL DISTANCE AS A FACTOR OF INTER-ETHNIC ATTITUDES FORMATION AMONG THE YOUTH FROM THE ALTAY REGION
Authors: Schaihislamov Rafael B. , Maximova Svetlana G. , Surtaeva Olga V. , Omelchenko Daria A.
Published: February 2021

Social distance is closely interlinked with inter-ethnic attitudes, and there is a need in a sociological analysis of these phenomena, especially among young people, more vulnerable to the risks of ethnic intolerance and xenophobia. In 2020 in the Altay region a sociological survey was conducted among the young people from 14 to 35 years old (n=507). The article presents its results, revealing the interrelation between inter-ethnic attitudes and social distance with different ethnic groups. It was found that a little distance forms positive context of inter-ethnic relations but can lead to erosion and confusion of ethnic identity among youth. The results obtained can be used as a basis for elaboration of strategies guiding positive ethnic identity formation and grounds for measures of youth policy in the Russian Federation.
EURASISM AS ONE OF THE IDEOLOGICAL FOUNDATIONS OF RUSSIA'S SECURITY IN THE XX AND XXI CENTURIES: POLITICAL AND LEGAL VIEWS L.N. GUMILYOV AND V.V. KOZHINOV
Authors: Kulikov Egor A.
Published: February 2021

The instability of the situation in the Eurasian space, renewed conflicts in the Transcaucasus, political events in Belarus and individual cities of Russia, on the one hand, and the ongoing integration processes in the post-Soviet space between states and peoples that are close in historical memory and national-cultural values, on the other, - determine the relevance of the issue of the ideological security of Russia, as well as the ideological support of these integration processes. The political and legal doctrine of Eurasianism substantiates the inevitability of the common fate of the peoples inhabiting the territory of the former Russian Empire and the USSR, determines the grounds for the peaceful coexistence of these peoples, as well as their interaction, from various sides and positions. This article examines the political and legal views of the later representatives of Eurasianism - L.N. Gumilyov and V.V. Kozhinov. The method of working with primary sources, the comparative method, the historical method, partly the method of ascent from the concrete to the abstract is used. It is concluded that the named thinkers develop in their works a civilizational approach to history, society, the state, and also determine the ideological foundations of national unity on the territory of Russia-Eurasia. It should be noted that despite the extensive bibliography of studies of Eurasianism in legal science, the works of V.V. Kozhinov and L.N. Gumilyov are rarely touched upon by scientists. Meanwhile, L.N. Gumilev brought the civilizational approach to the level of the scientific theory of ethnogenesis, developed in detail the concept of passionarity, and V.V. Kozhinov is the largest Russian historian of the XX century and offers a balanced and reasonable approach to this period of development of our country.
COMPARATIVE ANALYSIS OF THE ELECTORAL ACTIVITY OF YOUTH IN THE ALTAI REPUBLIC IN 2014 AND 2019
Authors: Sharapov Alexey V.
Published: February 2021

In the total population of the Altai Republic, a significant proportion of it is youth. This demographic group is most susceptible to various value attitudes (democratic, authoritarian, radical behavior). The stability of an entire region depends on the correct upbringing of young people. The aim of the study is to study the representation of young people in government and local governments. The lists of candidates for the head of the Republic, deputies of El Kurultai, heads and deputies of local self-government bodies, nominated during the election campaign of 2014 and 2019, were analyzed. As a result of comparing the results of two electoral cycles, an increase in the number of elected young candidates to various authorities was revealed.
NEW HIGHER EDUCATION: HARMONIZING ON-LINE AND OFF-LINE FORMATS IN THE CONTEXT OF GLOBAL CHALLENGES
Authors: Kozhevina Olga V.
Published: February 2021

The competitiveness of education is due to global trends in modern society. The preferences of students are changing, professional standards are being developed, and employers are making new demands on graduates. These trends are characteristic of vocational secondary, higher and additional education. At any level of education, its own specifics, however, modern innovative technologies, distance forms and online formats are becoming more and more familiar in the construction of the educational process. This article discusses the principles of forming a digital educational environment and its elements. Some foreign experience in the implementation of distance learning and personalization of training in the context of the global challenges of COVID-19 is summarized.
SOCIOLOGICAL ANALYSIS OF THE USE OF AUGMENTED REALITY TECHNOLOGY IN EDUCATION
Authors: Baigabylov Nurlan O. , Baigusheva Bayan M. , Baigusheva Kanagat M.
Published: February 2021

Augmented reality is increasingly used in education and its further spread is predicted as one of the technological trends. The benefits of using augmented reality are contributing to the increasing use of augmented reality in education. The purpose of the research is to study the use of augmented reality technology in teaching. The article provides the overview of the development of augmented reality and presents the results of a survey of teachers who attended the advanced training course. According to the results of the survey, the readiness of teachers to use this technology and the feasibility of its use in various methods and forms of training organization were determined. A special feature of the use of augmented reality in education is its accessibility and ease of use of ready-made mobile applications and services.
INFORMATION AND COMMUNICATION TECHNOLOGIES. INFLUENCE ON KNOWLEDGE PROCESSES FOR SCHOOLCHILDREN
Authors: Razvarina Irina N. , Kalachikova Olga N.
Published: February 2021

Modern society is at a new informational stage of development. This led to the modernization of communication tools and the emergence of new types of cognitive activity of man, in particular, «clip thinking. Since «clip thinking” is formed in childhood, an assessment of the impact of Internet communication and the use of «gadgets» on the formation of cognitive processes in children, as one of the components of human potential, can help in solving this problem. The purpose of the manuscript was to assess the impact of the use of ICTs and electronic devices on the formation of memory, attention, thinking, imagination, digital skills in school children. It was determined that the constant use of «smart»technology and Internet resources by children has an adverse effect on the formation of memorization, thinking and attention skills, as well as academic performance and school motivation. Scientific novelty lies in the ability to assess the level of development of cognitive processes in schoolchildren under the influence of ICT using the sub-index of intellectual development developed by the scientific group, the index of the human potential of the child population. The obtained data can be used in the formation of family policy programs, the development of educational organizations, professional development of teachers, psychologists, social educators, parents.
A patient-independent classification system for onset detection of seizures
Authors: Ansari Abdul Quaiyum , Sharma Priyanka , Tripathi Manjari
Published: February 2021

Seizures are the most common brain dysfunction. Electroencephalography (EEG) is required for their detection and treatment initially. Studies show that if seizures are detected at their early stage, instant and effective treatment can be given to the patients. In this paper, an automated system for seizure onset detection is proposed. As the power spectrum of normal person’s EEG and EEG of someone with epilepsy is plotted, powers present at different frequencies are found to be different for both. The proposed algorithm utilizes this frequency discrimination property of EEG with some statistical features to detect the seizure onset using simple linear classifier. The tests conducted on EEG data of 30 patients, obtained from the two different datasets, show the presence of all 183 seizures with mean latency of 0.9 s and 1.02 false detections per hour. The main contribution of this study is the use of simple features and classifier in the field of seizures onset detection that reduces the computational complexity of the algorithm. Also, the classifier used is patient independent. This patient independency in the classification system would be helpful in the implementation of the proposed algorithm to develop an online detection system.
Qualitative and semi-quantitative assessment of anthocyanins in Tibetan hulless barley from different geographical locations by UPLC-QTOF-MS and their antioxidant capacities
Authors: Zhang Tangwei , Ma Jialin , Wu Xuelian , Hao Zhihua , Dun Ci , Chen Chen
Published: February 2021

Tibetan hulless barley (“qingke” in Chinese) is a valuable food in Tibet. Purple qingke (PQK) and black qingke (BQK), two special pigmented types of hulless barley, have traditionally been widely cultivated and consumed in Tibet for thousands of years. The composition and contents of anthocyanins of two cultivars are unknown. This study aimed to explore the composition and contents of anthocyanins of two cultivars and their antioxidant capacities. Six anthocyanins were identified by ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometry from barley, most of the anthocyanins were acylated by malonyl group. The total anthocyanin contents ranged from 141 to 2,304 μg/g in PQK and from 248.7 to 2902.9 μg/g in BQK. Furthermore, qingke has strong antioxidant activity against DPPH, ABTS˙+, and FRAP. Qingke may be useful for treating or preventing diseases caused by the overproduction of radicals.
Overview of the major classes of new psychoactive substances, psychoactive effects, analytical determination and conformational analysis of selected illegal drugs
Authors: Lukić Vera , Micić Ružica , Arsić Biljana , Nedović Bojan , Radosavljević Živana
Published: February 2021

The misuse of psychoactive substances is attracting a great deal of attention from the general public. An increase use of psychoactive substances is observed among young people who do not have enough awareness of the harmful effects of these substances. Easy access to illicit drugs at low cost and lack of effective means of routine screening for new psychoactive substances (NPS) have contributed to the rapid increase in their use. New research and evidence suggest that drug use can cause a variety of adverse psychological and physiological effects on human health (anxiety, panic, paranoia, psychosis, and seizures). We describe different classes of these NPS drugs with emphasis on the methods used to identify them and the identification of their metabolites in biological specimens. This is the first review that thoroughly gives the literature on both natural and synthetic illegal drugs with old known data and very hot new topics and investigations, which enables the researcher to use it as a starting point in the literature exploration and planning of the own research. For the first time, the conformational analysis was done for selected illegal drugs, giving rise to the search of the biologically active conformations both theoretically and using lab experiments.
Influence of nanoscale-modified apatite-type calcium phosphates on the biofilm formation by pathogenic microorganisms
Authors: Grynyuk Iryna I. , Vasyliuk Olga M. , Prylutska Svitlana V. , Strutynska Nataliia Yu. , Livitska Oksana V. , Slobodyanik Mykola S.
Published: February 2021

Nanoparticles (25–50 nm) of chemically modified calcium phosphates Ca10−x−y
M
ii

x
Na
y
(PO4)6−z
(CO3)
z
(OH)2 (M
ii
 – Cu2+, Zn2+) were synthesized via a wet precipitation method at room temperature. The Fourier-transform infrared spectroscopy data confirmed the partial substitution of

PO

4

3
−

{\text{PO}}_{4}^{3-}

→

CO

3

2
−

{\text{CO}}_{3}^{2-}

(B-type) in apatite-type structure. The influence of prepared phosphates on biofilm formation by pathogenic microorganisms was investigated. It was found that the samples Na+,

CO

3

2
−

{\text{CO}}_{3}^{2-}

-hydroxyapatite (HAP) and Na+, Zn2+,

CO

3

2
−

{\text{CO}}_{3}^{2-}

-HAP (5–20 mM) had the highest inhibitory effect on biofilm formation by Staphylococcus aureus strains. The sample Na+,

CO

3

2
−

{\text{CO}}_{3}^{2-}

-HAP had the slight influence on the formation of the biofilm by Pseudomonas aeruginosa, while for the samples Na+, Cu2+,

CO

3

2
−

{\text{CO}}_{3}^{2-}

-HAP and Na+, Zn2+,

CO

3

2
−

{\text{CO}}_{3}^{2-}

-HAP such an effect was not detected. According to transmission electron microscopy data, a correlation between the activity of synthesized apatite-related modified calcium phosphates in the processes of biofilm formation and their ability to adhere to the surface of bacterial cells was established. The prepared samples can be used for the design of effective materials with antibacterial activity for medicine.
Defects in Active Nematics – Algorithms for Identification and Tracking
Authors: Wenzel Dennis , Nestler Michael , Reuther Sebastian , Simon Maximilian , Voigt Axel
Published: February 2021

The growing interest in active nematics and the emerging evidence of the relevance of topological defects in biology asks for reliable data analysis tools to identify, classify and track such defects in simulation and microscopy data. We here provide such tools and demonstrate on two examples, on an active turbulent state in an active nematodynamic model and on emerging nematic order in a multi-phase field model, the possibility to compare statistical data on defect velocities with experimental results. The considered tools, which are physics based and data driven, are compared with each other.
Contractive Local Adaptive Smoothing Based on Dörfler’s Marking in A-Posteriori-Steeredp-Robust Multigrid Solvers
Authors: Miraçi Ani , Papež Jan , Vohralík Martin
Published: February 2021

In this work, we study a local adaptive smoothing algorithm for a-posteriori-steeredp-robust multigrid methods. The solver tackles a linear system which is generated by the discretization of a second-order elliptic diffusion problem using conforming finite elements of polynomial orderp≥1{p\geq 1}. After one V-cycle (“full-smoothing” substep) of the solver of [A. Miraçi, J. Papež, and M. Vohralík, A-posteriori-steeredp-robust multigrid with optimal step-sizes and adaptive number of smoothing steps, SIAM J. Sci. Comput. 2021, 10.1137/20M1349503], we dispose of a reliable, efficient, and localized estimation of the algebraic error. We use this existing result to develop our new adaptive algorithm: thanks to the information of the estimator and based on a bulk-chasing criterion, cf. [W. Dörfler, A convergent adaptive algorithm for Poisson’s equation, SIAM J. Numer. Anal. 33 1996, 3, 1106–1124], we mark patches of elements with increased estimated error on all levels. Then, we proceed by a modified and cheaper V-cycle (“adaptive-smoothing” substep), which only applies smoothing in the marked regions. The proposed adaptive multigrid solver picks autonomously and adaptively the optimal step-size per level as in our previous work but also the type of smoothing per level (weighted restricted additive or additive Schwarz) and concentrates smoothing to marked regions with high error. We prove that, under a numerical condition that we verify in the algorithm, each substep (full and adaptive) contracts the errorp-robustly, which is confirmed by numerical experiments. Moreover, the proposed algorithm behaves numerically robustly with respect to the number of levels as well as to the diffusion coefficient jump for a uniformly-refined hierarchy of meshes.
Sensor Number Optimization Using Neural Network for Ankle Foot Orthosis Equipped with Magnetorheological Brake
Authors: Adiputra Dimas , Azizi Abdul Rahman Mohd , Bahiuddin Irfan , Ubaidillah  , Imaduddin Fitrian , Nazmi Nurhazimah
Published: February 2021

A passive controlled ankle foot orthosis (PICAFO) used a passive actuator such as Magnetorheological (MR) brake to control the ankle stiffness. The PICAFO used two kinds of sensors, such as Electromyography (EMG) signal and ankle position (two inputs) to determine the amount of stiffness (one output) to be generated by the MR brake. As the overall weight and design of an orthotic device must be optimized, the sensor numbers on PICAFO wanted to be reduced. To do that, a machine learning approach was implemented to simplify the previous stiffness function. In this paper, Non-linear Autoregressive Exogeneous (NARX) neural network were used to generate the simplified function. A total of 2060 data were used to build the network with detail such as 1309 training data, 281 validation data, 281 testing data 1, and 189 testing data 2. Three training algorithms were used such as Levenberg-Marquardt, Bayesian Regularization, and Scaled Conjugate Gradient. The result shows that the function can be simplified into one input (ankle position) – one output (stiffness). Optimized result was shown by the NARX neural network with 15 hidden layers and trained using Bayesian Regularization with delay 2. In this case, the testing data shows R-value of 0.992 and MSE of 19.16.
Selection of a workpiece clamping system for computer-aided subtractive manufacturing of geometrically complex medical models
Authors: Wojnarowska Wiktoria , Kwolek Maciej , Miechowicz Sławomir
Published: February 2021

Physical models of anatomical structures can be made using Additive Manufacturing (AM) or Subtractive Manufacturing (SM). The advantage of subtractive techniques over additive ones is the possibility of maintaining the homogeneity and consistency of the processed material, which is extremely important in the case of medical devices. Currently, a geometrically complex medical model can be made even on a simple, 3-axis CNC machine tool. However, often the semi-finished product must be machined in at least two clamping configurations. The aim of the work is to present the method of fixing a workpiece in the process of subtractive production of geometrically complex medical objects on the example of skull bone prostheses. The paper discusses the use of two clamping systems for machining such models. It presents the process of subtractive production of bone prostheses models fitted to the defect of the skull bone with the use of the proposed methods of fixing the workpiece. The result of the work are two models of the skull bone prosthesis. A more complex model was analysed in terms of the accuracy of geometry reproduction. The research confirmed the usefulness of the proposed clamping systems for the preparation of medical models of geometrically complex anatomical structures.
Vocational Student's Attitude and Response Towards Experiential Learning in Mechanical Engineering
Authors: Fajar Pamungkas Stephanus , Widiastuti Indah , Suharno
Published: February 2021

This study evaluated the use of an experiential learning design for vocational education in mechanical engineering. The research objective is to analyze students’ attitudes and responses after participating in learning activities using a worksheet designed according to Kolb's stages by considering Felder-Silverman's student learning styles. This research was conducted using a case study research employing qualitative data analysis. The data were collected using a purposive random sampling technique with 28 respondents in a 10th grade. The datawere analyzed using descriptive qualitative analysis. The experiential learning activities were carried out concrete experience, reflective observations, abstract conceptualization, and active experimentation. It is shown that students have a positive attitude and response. Experiential activities help students in learning Basic of Mechanical Engineering and they enjoy participating in the learning activities. Experiential learning activities are considered to be fun, interesting, and easy to be understood. The students could relate the course material to real-life situations, which may benefit the students to enhance learning and connect the knowledge they learned to their own experiences. It is suggested that the experiential design is effectively used and could explore the relationship between learning theory and practice in Vocational High School.
Plastic forming processes of transverse non-homogeneous composite metallic sheets
Authors: Davidi Gal
Published: February 2021

In this work an analysis of the radial stress and velocity fields is performed according to the J
2 flow theory for a rigid/perfectly plastic material. The flow field is used to simulate the forming processes of sheets. The significant achievement of this paper is the generalization of the work by Nadai & Hill for homogenous material in the sense of its yield stress, to a material with general transverse non-homogeneity. In Addition, a special un-coupled form of the system of equations is obtained where the task of solving it reduces to the solution of a single non-linear algebraic differential equation for the shear stress. A semi-analytical solution is attained solving numerically this equation and the rest of the stresses term together with the velocity field is calculated analytically. As a case study a tri-layered symmetrical sheet is chosen for two configurations: soft inner core and hard coating, hard inner core and soft coating.

The main practical outcome of this work is the derivation of the validity limit for radial solution by mapping the “state space” that encompasses all possible configurations of the forming process. This configuration mapping defines the “safe” range of configurations parameters in which flawless processes can be achieved. Several aspects are researched: the ratio of material's properties of two adjacent layers, the location of layers interface and friction coefficient with the walls of the dies.
Forced convection heat transfer study of a blunt-headed cylinder in non-Newtonian power-law fluids
Authors: Kaur Jaspinder , Melnik Roderick , Tiwari Anurag Kumar
Published: February 2021

In this present work, forced convection heat transfer from a heated blunt-headed cylinder in power-law fluids has been investigated numerically over the range of parameters, namely, Reynolds number (Re): 1–40, Prandtl number (Pr): 10–100 and power-law index (n): 0.3–1.8. The results are expressed in terms of local parameters, like streamline, isotherm, pressure coefficient, and local Nusselt number and global parameters, like wake length, drag coefficient, and average Nusselt number. The length of the recirculation zone on the rear side of the cylinder increases with the increasing value of Re andn. The effect of the total drag coefficient acting on the cylinder is seen to be higher at the low value of Re and its effect significant in shear-thinning fluids (n < 1). On the heat transfer aspect, the rate of heat transfer in fluids is increased by increasing the value of Re and Pr. The effect of heat transfer is enhanced in shear-thinning fluids up to ∼ 40% and it impedes it’s to ∼20% shear-thickening fluids. In the end, the numerical results of the total drag coefficient and average Nusselt number (in terms ofJH−factor) have been correlated by simple expression to estimate the intermediate value for the new application.
Predictive model development and simulation of photobioreactors for algal biomass growth estimation
Authors: Banerjee Nilanjana
Published: February 2021

In the current scenario of energy requirement and the commercialization aspect of algal biofuel and biomass, it is important that means of predicting the production be available. In this paper, the mathematical models are developed for the tubular, bubble column and airlift photobioreactors to predict the productivity of the algal biomass. A modified Monod kinetic equation, incorporating the effect of nutrient and CO2 concentrations, light availability and oxygen built-up, is used to the estimate specific growth rate of the biomass. The light availability inside the reactor is defined in terms of the modified Beer–Lambert’s law as a function of distance from the surface where light is incident and the cell mass concentration. This allows a more accurate measurement of the shading effect. The equations are solved for different reactor types and their estimated productivities are successfully validated against values available in published literature. The model predicts comparatively better productivity for the tubular reactor (1.5 g/L day) than the bubble column and airlift reactor (1.42 and 1.35 g/L day respectively) because tubular reactor has shorter light/dark cycles and better light availability. The analysis is also done to identify the effect of nutrient, carbon dioxide, light and hydrodynamics on the overall productivity.
Hepatoprotective effects of Quassia amara stem bark against cadmium-induced toxicity in male Wistar rats
Authors: Obembe Olawale O. , Usman Taofeek O. , Raji Yinusa
Published: February 2021

Objectives

The liver is one of the primary biorepositories of cadmium (Cd) and it has been implicated in the pathogenesis of hepatic diseases. Quassia amara stem bark has been reputed to have strong antimalarial, antimicrobial, antiulcerative and amoebicidal properties. This study aims to determine the effects of Q. amara on Cd-induced hepatotoxicity and lipid profile in male Wistar rats.

Methods

The animals were divided into three groups of five animals each. Group 1 served as control while group 2 received Cd (5 mg/kg) for 4 weeks. Prior to Cd treatment, group 3 was treated with Q. amara extract (200 mg/kg) for 2 weeks and received the Q. amara and Cd simultaneously for 4 weeks.

Results

Cadmium caused significant increase in serum total cholesterol and low-density lipoprotein (LDL) as well as increased hepatic malondialdehyde (MDA) when compared with the control group. On the other hand, Cd caused a decrease in serum high-density lipoprotein (HDL) and hepatic superoxide dismutase (SOD) when compared with control. However, treatment with Q. amara prevented Cd-induced changes in the lipid profile, augmented Cd-induced decline in SOD and also ameliorated the Cd-induced increase in MDA. Catalase level was however comparable across the groups.

Conclusions

Q. amara ameliorated the Cd-induced damage to liver by preventing dyslipidemia and oxidative damage in the hepatic tissue.
Recognition of facial expression of fetuses by artificial intelligence (AI)
Authors: Miyagi Yasunari , Hata Toshiyuki , Bouno Saori , Koyanagi Aya , Miyake Takahito
Published: February 2021

Objectives

The development of the artificial intelligence (AI) classifier to recognize fetal facial expressions that are considered as being related to the brain development of fetuses as a retrospective, non-interventional pilot study.

Methods

Images of fetal faces with sonography obtained from outpatient pregnant women with a singleton fetus were enrolled in routine conventional practice from 19 to 38 weeks of gestation from January 1, 2020, to September 30, 2020, with completely de-identified data. The images were classified into seven categories, such as eye blinking, mouthing, face without any expression, scowling, smiling, tongue expulsion, and yawning. The category in which the number of fetuses was less than 10 was eliminated before preparation. Next, we created a deep learning AI classifier with the data. Statistical values such as accuracy for the test dataset and the AI confidence score profiles for each category per image for all data were obtained.

Results

The number of fetuses/images in the rated categories were 14/147, 23/302, 33/320, 8/55, and 10/72 for eye blinking, mouthing, face without any expression, scowling, and yawning, respectively. The accuracy of the AI fetal facial expression for the entire test data set was 0.985. The accuracy/sensitivity/specificity values were 0.996/0.993/1.000, 0.992/0.986/1.000, 0.985/1.000/0.979, 0.996/0.888/1.000, and 1.000/1.000/1.000 for the eye blinking, mouthing, face without any expression, scowling categories, and yawning, respectively.

Conclusions

The AI classifier has the potential to objectively classify fetal facial expressions. AI can advance fetal brain development research using ultrasound.
The impact of transfers from neonatal intensive care to paediatric intensive care
Authors: Williams Emma E. , Lee Rebecca , Williams Nia , Deep Akash , Subramaniam Nadisha , Dwarakanathan Buvana , Dassios Theodore , Greenough Anne
Published: February 2021

Objectives

Infants receiving care from neonatal intensive care unit (NICU) can develop chronic problems and be transferred to a paediatric intensive care unit (PICU) for on-going care. There is concern that such infants may take up a large amount of PICU resource, but this is not evidence based. We determined the impact of such transfers.

Methods

We reviewed 10 years of NICU admissions to two tertiary PICUs, which had approximately 12,000 admissions during that period.

Results

Sixty-seven infants, gestational age at birth 34.7 (IQR 27.1–38.8) weeks and postnatal age on transfer 81 (IQR 9–144) days were admitted from NICUs. The median (IQR) length of stay was 12 (4–41) days. The 19 infants born <28 weeks of gestation had a greater median length of stay (32, range IQR 10–93 days) than more mature born infants (7.5, IQR 4–26 days) (p=0.003). The median cost of PICU stay for NICU transfers was £23,800 (range 1,205–1,034,000) per baby. The total cost of care for infants transferred from NICUs was £6,457,955.

Conclusions

Infants transferred from NICUs were a small proportion of PICU admissions but, particularly those born <28 weeks of gestation, had prolonged stays which needs to be considered when determining bed capacity.
Topological polarization singularities in metaphotonics
Authors: Liu Wenzhe , Liu Wei , Shi Lei , Kivshar Yuri
Published: February 2021

Polarization singularities of vectorial electromagnetic fields locate at the positions where properties of polarization ellipses are not defined. First observed for conical diffraction in 1830s, polarization singularities have been studied systematically with the underlying concepts being reshaped and deepened by many pioneers of wave optics. Here we review the recent results on the generation and observation ofpolarization singularities in metaphotonics. We start with the discussion of polarization singularities in the Mie theory, where both electric and magnetic multipoles are explored from perspectives of local and global polarization properties. We then proceed with the discussion of various photonic-crystal structures, for which both near- and far-field patterns manifest diverse polarization singularities characterized by the integer Poincaré or more general half-integer Hopf indices (topological charges). Next, we review the most recent studies of conversions from polarization to phase singularities in scalar wave optics, demonstrating how bound states in the continuum can be exploited to generate directly optical vortices of various charges. Throughout our paper, we discuss and highlight several fundamental concepts and demonstrate their close connections and special links to metaphotonics. We believe polarization singularities can provide novel perspectives for light-matter manipulation for both fundamental studies and their practical applications.
Magnetic behavior of Fe-doped of multicomponent bismuth niobate pyrochlore
Authors: Zhuk Nadezhda A. , Makeev Boris A. , Nekipelov Sergey V. , Yermolina Maria V. , Fedorova Anna V. , Chernykh Galina I.
Published: February 2021

Two series of iron-containing solid solutions Bi2Mg1−x
Fe
x
Nb2O9+δ
and Bi2MgNb2−2x
Fe2x
O9−δ
of pyrochlore structure were obtained by the traditional solid phase synthesis method. The electronic state and character of exchange interactions of iron atoms in solid solutions were investigated by methods of magnetic dilution and NEXAFS-spectroscopy. According to X-ray spectroscopy and magnetic susceptibility data, iron(III) atoms are distributed mainly in octahedral positions of niobium(V) and in a dominant amount are in the charge state of Fe(III) in the form of monomers and exchange-bonded clusters mainly with antiferromagnetic type of exchange. Differences in magnetic behavior of iron-containing solid solutions of both series have been revealed. Antiferromagnetic and ferromagnetic exchange can be realized between iron atoms, which, with increasing concentration of paramagnetic atoms and averaging structure distortions, becomes less significant. The parameters of exchange interactions in clusters and distribution of iron paramagnetic atoms depending on the concentration of solid solutions have been calculated.