bluuebunny/crossref_metadata_2025 huggingface dataset:
Deep learning and capsule endoscopy: automatic identification and differentiation of small bowel lesions with distinct haemorrhagic potential using a convolutional neural network
Authors: Mascarenhas Saraiva Miguel José , Afonso João , Ribeiro Tiago , Ferreira João , Cardoso Helder , Andrade Ana Patricia , Parente Marco , Natal Renato , Mascarenhas Saraiva Miguel , Macedo Guilherme
Published: September 2021

Objective

Capsule endoscopy (CE) is pivotal for evaluation of small bowel disease. Obscure gastrointestinal bleeding most often originates from the small bowel. CE frequently identifies a wide range of lesions with different bleeding potentials in these patients. However, reading CE examinations is a time-consuming task. Convolutional neural networks (CNNs) are highly efficient artificial intelligence tools for image analysis. This study aims to develop a CNN-based model for identification and differentiation of multiple small bowel lesions with distinct haemorrhagic potential using CE images.

Design

We developed, trained, and validated a denary CNN based on CE images. Each frame was labelled according to the type of lesion (lymphangiectasia, xanthomas, ulcers, erosions, vascular lesions, protruding lesions, and blood). The haemorrhagic potential was assessed by Saurin’s classification. The entire dataset was divided into training and validation sets. The performance of the CNN was measured by the area under the receiving operating characteristic curve, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

Results

A total of 53 555 CE images were included. The model had an overall accuracy of 99%, a sensitivity of 88%, a specificity of 99%, a PPV of 87%, and an NPV of 99% for detection of multiple small bowel abnormalities and respective classification of bleeding potential.

Conclusion

We developed and tested a CNN-based model for automatic detection of multiple types of small bowel lesions and classification of the respective bleeding potential. This system may improve the diagnostic yield of CE for these lesions and overall CE efficiency.
Following the science? Views from scientists on government advisory boards during the COVID-19 pandemic: a qualitative interview study in five European countries
Authors: Colman Elien , Wanat Marta , Goossens Herman , Tonkin-Crine Sarah , Anthierens Sibyl
Published: September 2021

Introduction

In order to tackle the pandemic, governments have established various types of advisory boards to provide evidence and recommendations to policy makers. Scientists working on these boards have faced many challenges, including working under significant time constraints to produce ‘evidence’ as quickly as possible. However, their voices are still largely missing in the discussion. This study explores the views and experiences of scientists working on government advisory boards during the COVID-19 pandemic, with the aim to learn lessons for future pandemic management and preparedness.

Methods

We conducted online video or telephone semi-structured interviews between December 2020 and April 2021 with 21 scientists with an official government advisory role during the COVID-19 pandemic in Belgium, the Netherlands, UK, Sweden and Germany. The interviews were audio-recorded and transcribed and analysed using a combination of inductive and deductive thematic analysis techniques.

Results

Scientists viewed the initial focus on biomedically oriented work during the pandemic as somewhat one-dimensional, but also highlighted difficulties of working in an interdisciplinary way. They found it difficult at times to ensure that the evidence is understood and taken on board by governments. They found themselves taking on new roles, the boundaries of which were not clearly defined. Consequently, they were often perceived and treated as a public figure.

Conclusion

Scientists working on advisory boards in European countries faced similar challenges, highlighting key lessons to be learnt. Future pandemic preparedness efforts should focus on building interdisciplinary collaboration through development of scientists’ skills and appropriate infrastructure; ensuring transparency in how boards operate; defining and protecting the boundaries of the scientific advisor role; and supporting scientists to inform the public in the fight against disinformation, while dealing with potential hostile reactions.
COVID-19 and maternity care in South East London: shared working and learning initiative
Authors: Steward Emily , Kempen Jacqui , Wright Caroline , Postlethwaite Carol , Franklin Monica , Onwubalili Laura , Hameed Aisha , Bhatti Sadia , Olowu Oladimeji , Rajasingam Daghni , Banerjee Anita
Published: September 2021

The SARS-CoV-2 COVID-19 pandemic has had an immediate and profound impact on how healthcare systems organise and deliver services and specifically, there is a disproportionate negative impact on Black, Asian and Minority Ethnic groups and other risk factors. This has required clinical leaders to respond at pace to meet patient’s care needs, while supporting staff working in a volatile, uncertain, complex and ambiguous environment. During the initial wave and then the later waves within our South East London sector, there were new challenges as everyone faced a novel disease necessitating real-time learning and reflection. Through informal conversations and networks, the clinicians highlighted in the first wave the need for a forum for clinical discussion. Using our existing South East London Local Maternity System and the evolving Maternal Medicine Networks alliance, we initiated a sharing and learning platform to support clinical decision-making for all maternity health professionals during the pandemic. Fortnightly, multidisciplinary virtual huddles were established allowing obstetric physicians, obstetricians, midwives and obstetric anaesthetists to share their clinical experience, operational and service challenges. This approach fostered and developed cross-site team working and shared learning across traditional, organisational boundaries. In South East London, prior to the introduction of universal testing in the first surge, we had a total of 65 confirmed positive cases of which 5 women were delivered due to COVID-19, 5 women required high dependency or intensive care and 3 women were intubated and ventilated. During the second and third waves, the COVID-19 Local Maternity System huddles provided monthly learning opportunities to share clinical practice, guidelines, vaccination updates and challenges with workforce. The huddles have proven to be a sustainable platform, which have built trust across the sector, facilitating effective teamwork and providing invaluable support for clinical decision-making. We describe the evolution of this structure and share our experience of working within this new clinical network during the first wave and how this established way of working facilitated collaboration during the second and third waves as staff and the system became more fatigued. The huddles have developed to become multi-professional, multisite collaborations with the whole group taking joint ownership to develop shared learning and are providing a forum for discussions for the emerging South East London’s Maternal Medicine Network.
Serum Magnesium Levels in Hospitalized Patients with SARS-CoV-2
Authors: Sharma Rupam , Heidari Arash , Johnson Royce H , Advani Shailesh , Petersen Greti
Published: September 2021

Early studies have reported various electrolyte abnormalities at admission in patients with severe COVID-19. 104 out of 193 patients admitted to our institution presented with hypermagnesemia at presentation. It is believed this may be important in the evaluation of severe SARS-CoV-2 infections. This study evaluated the outcomes of hypermagnesemia in patients with COVID-19. A retrospective chart review of patients admitted to the hospital with confirmed SARS-CoV-2 infection was conducted. A review of the medical literature regarding hypermagnesemia, magnesium levels in critical care illness and electrolyte abnormalities in patients with COVID-19 was performed. Differences in demographic and clinical characteristics of patients with hypermagnesemia and normomagnesemia were evaluated using descriptive statistics. Other known variables of disease severity were analyzed. 104 patients (54%) were identified with hypermagnesemia (≥2.5 mg/dL). 48 of those patients were admitted to the intensive care unit (46%, p<0.001). 34 patients required ventilator support (32%, p<0.0001). With age-adjusted logistic regression analysis hypermagnesemia was associated with mortality (p=0.007). This study demonstrates that hypermagnesemia is a significant marker of disease severity and adverse outcome in SARS-CoV-2 infections. We recommend serum magnesium be added to the panel of tests routinely ordered in evaluation of severe SARS-CoV-2 infections.
Advances in the management of pulmonary arterial hypertension
Authors: Deshwal Himanshu , Weinstein Tatiana , Sulica Roxana
Published: September 2021

The management of pulmonary arterial hypertension (PAH) has significantly evolved over the last decades in the wake of more sensitive diagnostics and specialized clinical programs that can provide focused medical care. In the current era of PAH care, 1-year survival rates have increased to 86%–90% from 65% in the 1980s, and average long-term survival has increased to 6 years from 2.8 years. The heterogeneity in the etiology and disease course has opened doors to focusing research in phenotyping the disease and understanding the pathophysiology at a cellular and genetic level. This may eventually lead to precision medicine and the development of medications that may prevent or reverse pulmonary vascular remodeling. With more insight, clinical trial designs and primary end-points may change to identify the true survival benefit of pharmacotherapy. Identifying responders from non-responders to therapy may help provide individualized patient-centered care rather than an algorithm-based approach. The purpose of this review is to highlight the latest advances in screening, diagnosis, and management of PAH.
Eosinophilic features in clear cell renal cell carcinoma correlate with outcomes of immune checkpoint and angiogenesis blockade
Authors: Yoshida Takashi , Ohe Chisato , Ikeda Junichi , Atsumi Naho , Ohsugi Haruyuki , Sugi Motohiko , Higasa Koichiro , Saito Ryoichi , Tsuta Koji , Matsuda Tadashi , Kinoshita Hidefumi
Published: September 2021

Background

Clear cell renal cell carcinoma (ccRCC) displays heterogeneity in appearance—a distinctive pale clear to eosinophilic cytoplasm; however, little is known about the underlying mechanisms and clinical implications. We investigated the role of these eosinophilic features in ccRCC on oncological outcomes and response to tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs).

Methods

One-hundred and thirty-eight ccRCC cases undergoing radical surgery (cohort 1) and 54 metastatic ccRCC cases receiving either TKIs or ICIs (cohort 2) were included. After histological evaluation, all cases were divided into three phenotypes based on the eosinophilic features at the highest-grade area: clear, mixed, or eosinophilic type. Gene expression and immunohistochemical analyses were performed to explore the potential mechanisms of these phenotypes in cohort 1. Further, the association of the three phenotypes with the best objective response to TKI or ICI, clinical benefit (complete/partial response or stable disease), and overall survival (OS) was assessed in cohort 2.

Results

The clear type was significantly associated with increased hypoxia as well as angiogenesis gene signatures compared with the eosinophilic type. Gene signatures and protein expression related to effector T cell and immune checkpoint molecules were elevated to a greater extent in the eosinophilic type, followed by the mixed and clear types. The mixed and eosinophilic types exhibited greater PBRM1-negativity and increased prevalence of the epithelial-mesenchymal transition gene signature than the clear type. In the mixed/eosinophilic types of cohort 2, significant clinical benefit was observed in the ICI therapy group versus the TKI therapy group (p=0.035), and TKI therapy vs ICI therapy was an independent factor for worse prognosis of OS (HR 3.236; p=0.012).

Conclusion

The histological phenotype based on the eosinophilic features, which are linked to major immunological mechanisms of ccRCC, was significantly correlated with therapeutic efficacy.
‘Capable of being in uncertainties’: applied medical humanities in undergraduate medical education
Authors: Thacker Neepa , Wallis Jennifer , Winning Jo
Published: September 2021

Numerous medical schools have been updating and modernising their undergraduate curricula in response to the changing health needs of today’s society and the updated General Medical Council competencies required for qualification. The humanities are sometimes seen as a way of addressing both of these requirements. Medical humanities advocates would argue that the humanities have a vital role to play in undergraduate medical education, allowing students to develop the critical tools required by the 21st-century clinician to deliver the best person-centred care. While we endorse this view, we contend that such training must be taught authentically to have maximal impact. This article arises from a collaboration between Imperial College London and Birkbeck, University of London, which aimed to embed the humanities into Imperial’s undergraduate medical curriculum. Here, we use a teaching session on graphic medicine and narrative as a case study to illustrate how the humanities can be a powerful tool for students to explore professional clinical complexity and uncertainty when taught in a transdisciplinary way. In this session, uncertainty operated on several different levels: the introduction of unfamiliar concepts, materials, and methods to students, transdisciplinary approaches to teaching, and the complexities of real-life clinical practice. Further, we argue that to manage uncertainty, medical students must cross from a scientific training based on positivist understandings of evidence and knowledge, to one which foregrounds multiplicity, nuance, interpretive critical thinking, and which understands knowledge as contingent and contextually produced. In facilitating such learning, it is crucial that the teaching team includes experts from both medical and humanities fields to scaffold student learning in an intellectually dynamic way, drawing on their disciplinary knowledge and wide range of personal professional experiences.
It is not just about sex: viewpoints of men with inflammatory arthritis on the overall impact of the disease on their sexual health
Authors: Perez-Garcia Luis Fernando , Röder Esther , Pastoor Hester , Bolt Johanna M , van Exel Job , Dolhain Radboud J E M
Published: September 2021

Objectives

Sexual health is defined as a state of physical, emotional, mental and social well-being in relation to sexuality. The impact of inflammatory arthritis (IA) on male sexual health has been mainly studied focusing on erectile function, one of the physical components of sexual health. Our objective was to describe the viewpoints among men with IA in the Netherlands on the overall impact of IA on their sexual health.

Methods

Q-methodology, a mixed methods approach to systematically study subjectivity was used. Adult men diagnosed with IA ranked 34 opinion statements about potential impacts of IA on their sexual health and were interviewed. By-person factor analysis was used to identify common patterns in the rankings, which were interpreted as viewpoints. Data from the interviews were used to verify and adjust the interpretations.

Results

30 men (22–77 years) with IA were included. The analysis revealed three viewpoints. Men with the viewpoint ‘Arthritis negatively affects my sexual health’ experience a dramatic impact on all components of sexual health. In viewpoint ‘I am keeping up appearances’, IA negatively impacts sexual health but a distinguishing coping mechanism could mask a more serious negative impact. Men with the viewpoint ‘I am satisfied with my sexual health’' experience no significant impact of IA on their sexual health.

Conclusions

We identified three viewpoints on the impact of IA on male sexual health, two revealed a negative influence that goes beyond the physical act of sex. IA can severely affect the emotional, mental and social components of sexual health.
Lung function, airway and peripheral basophils and eosinophils are associated with molecular pharmacogenomic endotypes of steroid response in severe asthma
Authors: Kho Alvin T , McGeachie Michael J , Li Jiang , Chase Robert P , Amr Sami S , Hastie Annette T , Hawkins Gregory A , Li Xingnan , Chupp Geoffrey L , Meyers Deborah A , Bleecker Eugene R , Weiss Scott T , Tantisira Kelan G
Published: September 2021

Introduction

Asthma is a complex disease with heterogeneous expression/severity. There is growing interest in defining asthma endotypes consistently associated with different responses to therapy, focusing on type 2 inflammation (Th2) as a key pathological mechanism. Current asthma endotypes are defined primarily by clinical/laboratory criteria. Each endotype is likely characterised by distinct molecular mechanisms that identify optimal therapies.

Methods

We applied unsupervised (withouta prioriclinical criteria) principal component analysis on sputum airway cells RNA-sequencing transcriptomic data from 19 asthmatics from the Severe Asthma Research Program at baseline and 6–8 weeks follow-up after a 40 mg dose of intramuscular corticosteroids. We investigated principal components PC1, PC3 for association with 55 clinical variables.

Results

PC3 was associated with baseline Th2 clinical features including blood (rank-sum p=0.0082) and airway (rank-sum p=0.0024) eosinophilia, FEV1change (Kendall tau-b R=−0.333 (−0.592 to −0.012)) and follow-up FEV1albuterol response (Kendall tau-b R=0.392 (0.079 to 0.634)). PC1 with blood basophlia (rank-sum p=0.0191). The top 5% genes contributing to PC1, PC3 were enriched for distinct immune system/inflammation ontologies suggesting distinct subject-specific clusters of transcriptomic response to corticosteroids. PC3 association with FEV1change was reproduced in silico in a comparable independent 14-subject (baseline, 8 weeks after daily inhaled corticosteroids (ICS)) airway epithelial cells microRNAome dataset.

Conclusions

Transcriptomic PCs from this unsupervised methodology define molecular pharmacogenomic endotypes that may yield novel biology underlying different subject-specific responses to corticosteroid therapy in asthma, and optimal personalised asthma care. Top contributing genes to these PCs may suggest new therapeutic targets.
Soil nitrogen dynamics in canola agroecosystems of eastern Canada
Authors: Ejack Leanne , Gurung Bineeta , Seguin Philippe , Ma Bao-luo , Whalen Joann K.
Published: September 2021

Canola (Brassica napus L.) is a nitrogen (N)-demanding crop, so tissue N analysis should be related to soil N supply. We evaluated canola N uptake in relation to soil N pools in plots receiving 0, 50, 100, and 150 kg N·ha−1 from urea at three sites in eastern Canada in 2012. Soil N pools varied significantly at the rosette, flowering, pod filling, and maturity stages, but responded less predictably to urea. Canola N uptake was inconsistently related to soil N pools and urea input. This confirms the importance of site-specific N fertilizer management when growing canola in eastern Canada.
Relative skull size as one of the factors limiting skull shape variation in passerines
Authors: Shatkovska Oksana V. , Ghazali Maria
Published: September 2021

Despite a considerable interest among researchers in understanding the variation in skull shapes of birds and the factors influencing it, some of the drivers associated with the design features of an entire bird body, which are important for both successful terrestrial locomotion and flight, have been overlooked. One such factor, in our opinion, is relative skull size (skull length in relation to body mass), which can affect the position of the body’s center of gravity. We tested the effects of relative skull size, allometry (i.e., absolute skull size), and diet on variation in skull shape. The study was conducted on 50 songbird species representing a wide range of body masses (8.3–570 g) and dietary preferences (granivores, insectivores/granivores, insectivores, omnivores). Skull shape was analyzed using two-dimensional geometric morphometrics. We found that similar patterns of skull shape occur among passerines with different body sizes and diets. Relative skull size predicted skull shape to a similar extent and with a similar pattern as the absolute size. The effect of relative skull size on skull shape variation is likely due to biomechanical constraints related to flight.
Hierarchical microphase separation in non-conserved active mixtures
Authors: Li Yuting I. , Cates Michael E.
Published: September 2021

Non-equilibrium phase separating systems with reactions, such as biomolecular condensates and bacteria colonies, can break time-reversal symmetry (TRS) in two distinct ways. Firstly, the conservative and non-conservative sectors of the dynamics can be governed by incompatible free energies; when both sectors are present, this is the leading-order TRS violation, captured in its simplest form by ‘Model AB’. Second, the diffusive dynamics can break TRS in its own right. This happens only at higher order in the gradient expansion (but is the leading behaviour without reactions present) and is captured by ‘Active Model B+’ (AMB+). Each of the two mechanisms can lead to microphase separation, by quite different routes. Here we introduce Model AB+, for which both mechanisms are simultaneously present, and show that for slow reaction rates the system can undergo a new type of hierarchical microphase separation, which we call ‘bubbly microphase separation’. In this state, small droplets of one fluid are continuously created and absorbed into large droplets, whose length-scales are controlled by the competing reactive and diffusive dynamics.
Analytical new soliton wave solutions of the nonlinear conformable time-fractional coupled Whitham–Broer–Kaup equations
Authors: Sherriffe Delmar , Behera Diptiranjan , Nagarani P.
Published: September 2021

The study of nonlinear physical and abstract systems is greatly important in order to determine the behavior of the solutions for Fractional Partial Differential Equations (FPDEs). In this paper, we study the analytical wave solutions of the time-fractional coupled Whitham–Broer–Kaup (WBK) equations under the meaning of conformal fractional derivative. These solutions are derived using the modified extended tanh-function method. Accordingly, different new forms of the solutions are obtained. In order to understand its behavior under varying parameters, we give the visual representations of all the solutions. Finally, the graphs are discussed and a conclusion is given.
Effective Machine Learning Solutions for Punctual Weather Parameter Forecasting in a Real Missing Data Scenario
Authors: Impedovo Donato , Abbattista Giacomo , Convertini Nicola , Gattulli Vincenzo , Pirlo Giuseppe , Sarcinella Lucia
Published: September 2021

This work considers the Internet of Things (IoT) and machine learning (ML) applied to the agricultural sector within a real-working scenario. More specifically, the aim is to punctually forecast two of the most important meteorological parameters (solar radiation and the rainfall) to determine the amount of water needed by a specific plantation under different contour conditions. Three different state-of-the-art ML approaches, coupled with boosting techniques, have been adopted and compared to obtain hourly forecasting. Real-working conditions are referred to the situation in which training data are missing for a specific weather station near the specific field to be irrigated. A simple but effective approach, based on correlation between available weather stations, is considered to cope with this problem. Results, evaluated considering different metrics as well as the execution time, demonstrate the viability of the proposed solution in real IoT working scenario in which these forecasting are input data to successively evaluate irrigation needing.
Bifurcations of Heteroclinic Contours in Two-Parameter Planar Systems: Overview and Explicit Examples
Authors: Kuznetsov Yuri A. , Hooyman Joost
Published: September 2021

Smooth planar vector fields containing two hyperbolic saddles may possess contours formed by heteroclinic connections between these saddles. We present an overview of known results on bifurcations of these contours. Additionally, two new explicit polynomial systems containing such contours are derived, which are studied using the bifurcation software matcont and are shown to exhibit the theoretically predicted phenomena, including series of heteroclinic connections.
Dynamics of Delayed Phytoplankton–Zooplankton System with Disease Spread Among Zooplankton
Authors: Shi Renxiang
Published: September 2021

In this paper, we study the dynamics of phytoplankton–zooplankton system with delay, where delay means that releasing toxin for phytoplankton is not instantaneous. First, we prove the positivity and boundedness of solutions, discuss the Hopf bifurcation caused by delay. Furthermore, we study the property of Hopf bifurcation by center manifold and normal form. Then, we study the global existence of bifurcated periodic solution. Finally by simulation, we show the influence of delay, disease spread and recovery from infected to susceptible on the dynamics of phytoplankton–zooplankton system.
The Generalization of the Periodic Orbit Dividing Surface for Hamiltonian Systems with Three or More Degrees of Freedom – II
Authors: Katsanikas Matthaios , Wiggins Stephen
Published: September 2021

We develop a method for the construction of a dividing surface using periodic orbits in Hamiltonian systems with three or more degrees-of-freedom that is an alternative to the method presented in [ Katsanikas & Wiggins, 2021 ]. Similar to that method, for an [Formula: see text] degrees-of-freedom Hamiltonian system, we extend a one-dimensional object (the periodic orbit) to a [Formula: see text] dimensional geometrical object in the energy surface of a [Formula: see text] dimensional space that has the desired properties for a dividing surface. The advantage of this new method is that it avoids the computation of the normally hyperbolic invariant manifold (NHIM) (as the first method did) and it is easier to numerically implement than the first method of constructing periodic orbit dividing surfaces. Moreover, this method has less strict required conditions than the first method for constructing periodic orbit dividing surfaces. We apply the new method to a benchmark example of a Hamiltonian system with three degrees-of-freedom for which we are able to investigate the structure of the dividing surface in detail. We also compare the periodic orbit dividing surfaces constructed in this way with the dividing surfaces that are constructed starting with a NHIM. We show that these periodic orbit dividing surfaces are subsets of the dividing surfaces that are constructed from the NHIM.
Stochastic Transverse Earthquake-Induced Damage Track Irregularity Spectrum Considering the Uncertainty of Track-Bridge System
Authors: Feng Yulin , Hou Yu , Jiang Lizhong , Zhou Wangbao , Yu Jian , Guo Wenjie
Published: September 2021

The track irregularity spectrum of longitudinally connected ballastless track (LCBT)-bridge systems of high-speed railway was proposed in this paper. First, a simulation model of an LCBT-continuous girder bridge was established by considering the influences of approach bridges and subgrade with track structure. Further, a large number of sample analyses were carried out by taking into account the uncertainty of LCBT-bridge systems and stochastic behaviors of ground motions based on the simulation model. The damage laws of residual deformation of track-bridge system after earthquake actions were studied. Then, an interlayer deformation coordination relationship (IDCR) considering the track irregularity caused by earthquake-induced damage of bearings was developed, and the superposed track irregularity samples were obtained. Finally, by using the improved Blackman–Turkey method and Levenberg–Marquardt algorithm, the LCBT irregularity spectrum, track irregularity spectrogram, track irregularity limit spectrum, and a fitting formula for the track irregularity spectrum on a bridge after the action of earthquakes were obtained. Results obtained from the fitting formula and IDCR were compared, and they indicated that tracks undergone significant high-frequency irregularity diseases after the earthquake action. It was found that the track irregularity spectrum could be roughly divided into three ranges: high-, medium- and low-frequency wavebands. Consequently, this led to an application of a three-segment power function for the fitting of the track irregularity spectrum after the earthquake action. The track irregularity spectrum after the action of earthquakes provides an important theoretical basis for the establishment of seismic design methods for high-speed railway bridges based on the traffic safety performance.
Influences of Wind Barriers on the Train Running Safety on a Highway-Railway One-Story Bridge
Authors: Liu Ye , Han Yan , Hu Peng , Cai C. S. , He Xuhui
Published: September 2021

In this study, the influences of wind barriers on the aerodynamic characteristics of trains (e.g. a CRH2 train) on a highway-railway one-story bridge were investigated by using wind pressure measurement tests, and a reduction factor of overturning moment coefficients was analyzed for trains under wind barriers. Subsequently, based on a joint simulation employing SIMPACK and ANSYS, a wind–train–track–bridge system coupled vibration model was established, and the safety and comfort indexes of trains on the bridge were studied under different wind barrier parameters. The results show that the mean wind pressures and fluctuating wind pressures on the trains’ surface decrease generally if wind barriers are used. As a result, the dynamic responses of the trains also decrease in the whole process of crossing the bridge. Of particular note, the rate of the wheel load reductions and lateral wheel-axle forces can change from unsafe states to relative safe states due to the wind barriers. The influence of the porosity of the wind barriers on the mean wind pressures and fluctuating wind pressures on the windward sides and near the top corner surfaces of the trains are significantly greater than the influence from the height of the wind barriers. Within a certain range, decreasing the wind barrier porosities and increasing the wind barrier heights will significantly reduce the safety and comfort index values of trains on the bridge. It is found that when the porosity of the wind barrier is 40%, the optimal height of the wind barrier is determined as approximately 3.5[Formula: see text]m. At this height, the trains on the bridges are safer and run more smoothly and comfortably. Besides, through the dynamic response analysis of the wind–train–track–bridge system, it is found that the installation of wind barriers in cases with high wind speeds (30[Formula: see text]m/s) may have an adverse effect on the vertical vibration of the train–track–bridge system.
DESIGN OF CONTROLLABLE LEADER–FOLLOWER NETWORKS VIA MEMETIC ALGORITHMS
Authors: XIAO SHAOPING , SHE BAIKE , MEHTA SIDDHARTHA , KAN ZHEN
Published: September 2021

In many engineered and natural networked systems, there has been great interest in leader selection and/or edge assignment during the optimal design of controllable networks. In this paper, we present our pioneering work in leader–follower network design via memetic algorithms, which focuses on minimizing the number of leaders or the amount of control energy while ensuring network controllability. We consider three problems in this paper: (1) selecting the minimum number of leaders in a pre-defined network with guaranteed network controllability; (2) selecting the leaders in a pre-defined network with the minimum control energy; and (3) assigning edges (interactions) between nodes to form a controllable leader–follower network with the minimum control energy. The proposed framework can be applied in designing signed, unsigned, directed, or undirected networks. It should be noted that this work is the first to apply memetic algorithms in the design of controllable networks. We chose memetic algorithms because they have been shown to be more efficient and more effective than the standard genetic algorithms in solving some optimization problems. Our simulation results provide an additional demonstration of their efficiency and effectiveness.
A probe of cosmological models in modified teleparallel gravity
Authors: Dixit Archana , Pradhan Anirudh , Maurya Dinesh Chandra
Published: September 2021

In this paper, we have investigated the physical behavior of cosmological models in modified Teleparallel gravity with a general function [Formula: see text] where [Formula: see text] and [Formula: see text] are model parameters and [Formula: see text] is the torsion scalar. We have considered a homogeneous and isotropic Friedman universe filled with perfect fluid. We have derived the deceleration parameter [Formula: see text] in terms of equation of state (EoS) parameter [Formula: see text] and Hubble parameter [Formula: see text]. We have investigated the variation of [Formula: see text] over the observed values of Hubble constant in various observations within the range of redshift [Formula: see text]. Also, we have studied effective energy density [Formula: see text], effective pressure [Formula: see text] and effective EoS parameter [Formula: see text]. We have observed that the second term of [Formula: see text] function behaves just like variable cosmological term [Formula: see text] ([Formula: see text]) at late-time universe and causes the acceleration in expansion and works just like dark energy candidates. Also, we have evaluated the age of the present universe for various stages of matter [Formula: see text] and various [Formula: see text] functions.
Construction of Nano-Carriers Coated with Platelet Membrane and Its Application in Targeted Therapy of Inflammation
Authors: Ren Dandan , Xiao Tianyu , Lou Jiadong , Ren Rong , Ye Yuhan , Zhu Li-Min
Published: September 2021

In this study, poly (lactic acid-glycolic acid) (PLGA) nanoparticles loaded with anti-inflammatory drug ketoprofen (KET) were prepared and then coated with platelet membrane (PLTM) to form KET@PLTM-PLGA nano-particles (NPs). The particle size of the KET@PLTM-PLGA NPs is 176[Formula: see text]nm and the surface protein is the same as that of PLTM. The results of confocal microscopy and flow cytometry showed that the KET@PLTM-PLGA NPs uptake of RAW264.7 induced by LPS was significantly higher than that of KET@PLGA NPs, without PLTM, which was due to the binding of P-selectin to CD44 receptors on the surface of RAW264.7 cells induced by LPS on the surface of PLTM. Compared with other KET preparations, KET@PLTM-PLGA NPs have better anti-inflammatory effect.
Pendulum Motion Damped by Speed-Independent Friction
Authors: Mungan Carl E.
Published: September 2021

A pendulum without a supporting string or rod is obtained if a small block or marble is released at the rim of a spherical bowl or cylindrical half-pipe. This setup also applies to the familiar loop-the-loop demonstration. However, the bob will then experience sliding or rolling friction, which is speed independent in contrast to the linear or quadratic air drag which is more commonly used to model damping of oscillators. An analytic solution can be found for the speed of the bob as a function of its angular position around the vertical circular trajectory. A numerical solution for the time that the object takes to move from one turning point to the next shows that it is smaller than it would be in the absence of friction.
A New Thought Experiment on Relativistic Length Contraction
Authors: Raychaudhuri B. , Ghose S. , Bhadra A.
Published: September 2021

Relativistic length contraction is revisited and a simple but new thought experiment is proposed in which an apparent asymmetric situation is developed between two different inertial frames regarding detection of light that comes from a chamber to an adjacent chamber through a movable slit. The proposed experiment does not involve gravity, rigidity or any other dynamical aspect apart from the kinematics of relative motion; neither does it involve any kind of nonuniformity in motion. The resolution of the seemingly paradoxical situation has finally been discussed.
Synthesis of a Fe/Ca-based phosphate material and its application for adsorption of uranium ions from aqueous solution
Authors: Liu Haiyan , Zhang Weimin , Mo Jingyi , Wang Zhen , Chen Jiahong , Chen Junhua , Zhuo Zhen
Published: September 2021

Uranium (U) ion contamination in aquatic systems has received considerable attention worldwide. In this paper, an adsorption material was synthesized with a Fe/Ca-based phosphate (CFB-PM) by a sol–gel method. The effect of pH, reaction time and initial concentration of U ions on its capacity to remove U ions from aqueous solution was investigated via static batch experiments. Comparative studies of U ion removal by CFB-PM with four sorbents, namely: nano zero-valent iron (nZVI), hydroxyapatite (HAP), hydroxyapatite-loaded nano zero-valent iron (HAP@nZVI) and high basicity steel slag-loaded hydroxyapatite (HBSS@HAP), were performed. Results showed that U ion adsorption capacity of CFB-PM was better than that of all four. The adsorption capacity showed a decreasing order as: CFB-PM (643.34 mg g
–1
) > HAP (549.86  mg g
–1
) > HBSS@HAP (321.82  mg g
–1
) > HAP@nZVI (153.62  mg g
–1
) > nZVI (102.65  mg g
–1
). Scanning electron microscopy energy-dispersive spectrometry examination suggested that the adsorbed U ions were mainly in the form of spheres, sheets or petals on the surfaces of CFB-PM. X-ray diffraction revealed several U-bearing mineral phases (i.e. Ca(UO
2
)
2
(PO
4
)
2
·3H
2
O, HPUO
6
·4H
2
O and (UO
2
)
3
PO
4
·4H
2
O). The U ion adsorption behaviours were further explored by Fourier transform IR spectroscopy. The U ion adsorption process of CFB-PM could be well described by a quasi-second-order adsorption kinetics model and the Langmuir adsorption isotherm model. The separation coefficient (
R
L
) was close to zero, indicating that U ion adsorption was dominated by single-layer chemisorption. The findings reported in this study have implications for applying the synthesized material for remediation of U ion-contaminated groundwater.
Comparative Evaluation of Adaptation of Esthetic Prefabricated Fiberglass and CAD/CAM Crowns for Primary Teeth: Microcomputed Tomography Analysis
Authors: Oguz Ece Irem , Bezgin Tuğba , Orhan Ayse Isıl , Orhan Kaan
Published: September 2021

Adaptation is an important factor for the clinical success of restorations. However, no studies are available evaluating the adaptation of primary crowns. The aim of this study was to compare the adaptation of crowns fabricated by CAD/CAM technology versus prefabricated fiberglass primary crowns. Typodont maxillary central, canine, and mandibular molar teeth were prepared to serve as master dies after the size of Figaro crowns was determined (n = 10). Master dies were scanned with an intraoral scanner, and 10 identical CAD/CAM crowns were fabricated from resin‐ceramic blocks. Figaro and CAD/CAM crowns were placed on the corresponding master dies and scanned via micro‐CT. Three‐dimensional volumetric gap measurements were performed to evaluate the overall adaptation. A total of 255 location‐based linear measurements were allocated into 4 categories: marginal, cervical‐axial, middle‐axial, and occlusal. Statistical analyses were performed with factorial ANOVA, repeated measure ANOVA, and LSD tests (α = 0.05). CAD/CAM crowns showed significantly lower overall and location‐based gap measurements than Figaro crowns regardless of tooth number (p < 0.05). For all groups, mean marginal discrepancies were lower than occlusal measurements (p < 0.05). Both crown types showed higher marginal gaps for molar teeth than for canine and central incisors with no significant difference between them (p > 0.05). CAD/CAM‐fabricated crowns showed better marginal and internal adaptation than prefabricated Figaro crowns.
A Study on the Effect of Hollow Tubular Flange Sections on the Behavior of Cold‐Formed Steel Built‐Up Beams
Authors: Shanmugam Balaji , Palanisamy Manikandan , Awoyera Paul O. , Chinnasamy Senthilnathan , Subramaniam Mahalakshmi
Published: September 2021

This paper deals with a study conducted on flexural behavior of cold‐formed steel built‐up I‐beams with hollow tubular flange sections. There were two types of test sections, namely, built‐up sections that were assembled with either stiffened or unstiffened channels coupling back‐to‐back at the web and a hollow tubular rectangular flange at the top and bottom of the web to form built‐up I‐beam. The flexural behavior along with the strength and failure modes of the built‐up sections was examined using the four‐point loading system. Nonlinear finite element (FE) models were formulated and validated with the experimental test results. It was observed that the developed FE models had precisely predicted the behavior of built‐up I‐beams. Further, the verified FE models were used to conduct a detailed parametric study on cold‐formed steel built‐up beam sections with respect to thickness, depth, and yield stress of the material. The flexural strength of the beams was designed using the direct strength method as specified in American Iron and Steel Institute (AISI) for the design of cold‐formed steel structural members and was compared with the experimental results and the failure loads predicted from FE models. Since the results were not conservative, a new customized design equation had been mooted and delineated in the study for determining the flexural strength of cold‐formed steel built‐up beams with hollow tubular flange sections.
Adaptive Control of Space Robot Despinning Tumbling Target Using Flexible Brushes
Authors: Sun Shengxin , Wei Cheng , Huang Zhuoran , Wu Hao , Zhang Haibo , Lu Jianchun , Du Yan
Published: September 2021

A flexible brush mechanism is designed and mounted at the end of a seven-degree-of-freedom robotic arm to despin a tumbling target. The dynamics model of the flexible brush is established using the absolute nodal coordinate method (ANCF), and its contact collision with the solar wing of the tumbling target is analysed. The

H

∞

optimal control is proposed for a seven-degree-of-freedom robotic arm during despinning of a tumbling target while ensuring the global robustness and stability. Simulations verify that the despinning strategy can successfully eliminate the rotation speed and is feasible and effective.
Machine Learning Method for TOC Prediction: Taking Wufeng and Longmaxi Shales in the Sichuan Basin, Southwest China as an Example
Authors: Rong Jia , Zheng Zongyuan , Luo Xiaorong , Li Chao , Li Yuping , Wei Xiangfeng , Wei Quanchao , Yu Guangchun , Zhang Likuan , Lei Yuhong
Published: September 2021

The total organic carbon content (TOC) is a core indicator for shale gas reservoir evaluations. Machine learning-based models can quickly and accurately predict TOC, which is of great significance for the production of shale gas. Based on conventional logs, the measured TOC values, and other data of 9 typical wells in the Jiaoshiba area of the Sichuan Basin, this paper performed a Bayesian linear regression and applied a random forest machine learning model to predict TOC values of the shale from the Wufeng Formation and the lower part of the Longmaxi Formation. The results showed that the TOC value prediction accuracy was improved by more than 50% by using the well-trained machine learning models compared with the traditionalΔLogRmethod in an overmature and tight shale. Using the halving random search cross-validation method to optimize hyperparameters can greatly improve the speed of building the model. Furthermore, excluding the factors that affect the log value other than the TOC and taking the corrected data as input data for training could improve the prediction accuracy of the random forest model by approximately 5%. Data can be easily updated with machine learning models, which is of primary importance for improving the efficiency of shale gas exploration and development.
Effects of Ship Propulsion Shafting Alignment on Whirling Vibration and Bearing Temperature Response
Authors: Lei Junsong , Zhou Ruiping , Chen Hao , Huang Guobing , Gao Yakun , Yang Qingcao
Published: September 2021

Ship’s propulsion shafting is one of the main sources of ship vibration and noise. The shafting, whirling vibrations, and alignment are important factors that affect the comfort, stability, and reliability during a ship’s navigation. However, the mechanism of the interacting of the both factors is not fully revealed. In this paper, the effect of shafting alignment on whirling vibration and the bearing temperature response is studied by experiment. The test scheme is designed reasonably according to the theoretical analysis. The results show that the horizontal component of the shafting whirling vibration can be effectively reduced by adjusting the shafting alignment state while the vertical component is not. The shafting axis balancing position (SABP) slightly moves upward in high speed, which should be considered in the dynamic alignment design of the shafting, especially for the high-speed shafting. Little ABSB (the angle between the shafting centre line and the No. 1 bearing centre line) is beneficial to the stable operation of shafting, while appropriately increasing the ABSB and bearing load is beneficial to reducing the shafting whirling vibration. By balancing the relationship between bearing load and ABSB, the performance of whirling vibration and bearing temperature response can be optimized.
A Cross-Media Retrieval Method Based on Semisupervised Learning and Alternate Optimization
Authors: Li Junzheng , Zhu Wei , Yang Yanchun , Zheng Xiyuan
Published: September 2021

With the continuous advancement in Internet technology, we are gradually stepping into an era of big data where a large amount of multimedia data is produced every day at any given time. In order to properly utilize these data, the research on big data is also constantly evolving. Cross-media retrieval is a prime example, aiming at retrieving various forms of data, for example, text, image, audio, video, and other forms. The most difficult task for cross-media retrieval lies in the potential correlation between different modalities data and how to overcome the semantic gap. This paper proposes a cross-media retrieval method based on semisupervised learning and alternate optimization (SMDCR) to overcome the abovementioned difficulties, thereby improving the retrieval accuracy. The main advantage of this method is to make full use of the degree of correlation between the semantic information of the labeled data and unlabeled data. Simultaneously, we combine the linear regression term, correlation analysis term, and feature selection term into a joint cross-media learning framework. Furthermore, the projection matrices are trained with the alternate optimization method. Finally, experimental results on two public datasets demonstrate the effectiveness of the proposed method.