bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence of Tri-Exponential Decay for Liver Intravoxel Incoherent Motion MRI: A Review of Published Results and Limitations
Authors: Chevallier Olivier , Wáng Yì Xiáng J. , Guillen Kévin , Pellegrinelli Julie , Cercueil Jean-Pierre , Loffroy Romaric
Published: February 2021

Diffusion weighted imaging (DWI) and intravoxel incoherent motion (IVIM) have been explored to assess liver tumors and diffused liver diseases. IVIM reflects the microscopic translational motions that occur in voxels in magnetic resonance (MR) DWI. In biologic tissues, molecular diffusion of water and microcirculation of blood in the capillary network can be assessed using IVIM DWI. The most commonly applied model to describe the DWI signal is a bi-exponential model, with a slow compartment of diffusion linked to pure molecular diffusion (represented by the coefficient Dslow), and a fast compartment of diffusion, related to microperfusion (represented by the coefficient Dfast). However, high variance in Dfast estimates has been consistently shown in literature for liver IVIM, restricting its application in clinical practice. This variation could be explained by the presence of another very fast compartment of diffusion in the liver. Therefore, a tri-exponential model would be more suitable to describe the DWI signal. This article reviews the published evidence of the existence of this additional very fast diffusion compartment and discusses the performance and limitations of the tri-exponential model for liver IVIM in current clinical settings.
A Systematic Review of PET Textural Analysis and Radiomics in Cancer
Authors: Piñeiro-Fiel Manuel , Moscoso Alexis , Pubul Virginia , Ruibal Álvaro , Silva-Rodríguez Jesús , Aguiar Pablo
Published: February 2021

Background: Although many works have supported the utility of PET radiomics, several authors have raised concerns over the robustness and replicability of the results. This study aimed to perform a systematic review on the topic of PET radiomics and the used methodologies. Methods: PubMed was searched up to 15 October 2020. Original research articles based on human data specifying at least one tumor type and PET image were included, excluding those that apply only first-order statistics and those including fewer than 20 patients. Each publication, cancer type, objective and several methodological parameters (number of patients and features, validation approach, among other things) were extracted. Results: A total of 290 studies were included. Lung (28%) and head and neck (24%) were the most studied cancers. The most common objective was prognosis/treatment response (46%), followed by diagnosis/staging (21%), tumor characterization (18%) and technical evaluations (15%). The average number of patients included was 114 (median = 71; range 20–1419), and the average number of high-order features calculated per study was 31 (median = 26, range 1–286). Conclusions: PET radiomics is a promising field, but the number of patients in most publications is insufficient, and very few papers perform in-depth validations. The role of standardization initiatives will be crucial in the upcoming years.
Glycated Hemoglobin (HbA1c) as a Biomarker for Diabetic Foot Peripheral Neuropathy
Authors: Casadei Giulia , Filippini Marta , Brognara Lorenzo
Published: February 2021

Background: Diabetic peripheral neuropathy (DPN) is known to predict foot ulceration, lower-extremity amputation and mortality. Patients with diabetes mellitus have a predisposition toward developing chronic inflammatory demyelinating polyneuropathy, and this may also facilitate the formation of diabetic foot and cutaneous impairment, which are considered one of the most serious impairments of diabetes mellitus, with a prevalence of 4–10% in this population. Biomarkers research provides opportunities for the early diagnosis of these complications for specific treatments useful to prevent amputation and, therefore, physical inability and mental disturbance. The recent literature has suggested that glycemic levels may be a novel factor in the pathogenesis of diabetic foot complications and is an important mediator of axonal dysfunction. The aim of this systematic literary review is to determine whether hemoglobin A1c (HbA1c) is a positive predictor for diabetic foot peripheral neuropathy and its complications, such as foot cutaneous impairments. There is a lack of consensus regarding the effect of glycemic variability on diabetic foot peripheral neuropathy, unlike other complications such as retinopathy, nephropathy or micro/macrovascular pathology. Methods: Relevant articles were searched in the Medline database using PubMed and Scopus and relevant keywords. The primary search terms used were “glycated hemoglobin” OR “HbA1c” AND “diabetic neuropathies” AND “Foot”. Results: A number of articles (336) were initially identified while searching the scientific literature regarding this topic, and 32 articles were selected and included in this review. Conclusions: This review highlights the role of HbA1c in diabetic foot peripheral neuropathy. Biomarkers play an important role in the decision-making process, and HbA1c levels are extensively used for diabetic foot clinical outcomes and settings, but biomarker research in diabetic foot peripheral neuropathy is in its infancy and will require careful attention to a number of factors and associations, since the consequences of DPN also include neurological alterations. HbA1c is an accurate and easy-to-administer test and can be an effective biomarker in establishing the diagnosis of diabetes, but future research should focus on standardizing the HbA1c level and selecting which DPN value and its correlated complications, such as foot cutaneous impairments, are the most informative.
Customizable Vector Acceleration in Extreme-Edge Computing: A RISC-V Software/Hardware Architecture Study on VGG-16 Implementation
Authors: Sordillo Stefano , Cheikh Abdallah , Mastrandrea Antonio , Menichelli Francesco , Olivieri Mauro
Published: February 2021

Computing in the cloud-edge continuum, as opposed to cloud computing, relies on high performance processing on the extreme edge of the Internet of Things (IoT) hierarchy. Hardware acceleration is a mandatory solution to achieve the performance requirements, yet it can be tightly tied to particular computation kernels, even within the same application. Vector-oriented hardware acceleration has gained renewed interest to support artificial intelligence (AI) applications like convolutional networks or classification algorithms. We present a comprehensive investigation of the performance and power efficiency achievable by configurable vector acceleration subsystems, obtaining evidence of both the high potential of the proposed microarchitecture and the advantage of hardware customization in total transparency to the software program.
An Efficient Routing Protocol with Overload Control for Group Mobility in Delay-Tolerant Networking
Authors: Kang Min Wook , Chung Yun Won
Published: February 2021

In delay-tolerant networking (DTN), messages are delivered to destination nodes by using opportunistic contacts between contact nodes, even if stable routing paths from source nodes to destination nodes do not exist. In some DTN network environments, such as military networks, nodes movement follows a group movement model, and an efficient DTN routing protocol is required to use the characteristics of group mobility. In this paper, we consider a network environment, where both intra- and intergroup routing are carried out by using DTN protocols. Then, we propose an efficient routing protocol with overload control for group mobility, where delivery predictability for group mobility is defined and proactive overload control is applied. Performance evaluation results show that the proposed protocol had better delivery ratios and overhead ratios than compared protocols, although the delivery latency was increased.
Co-Simulation and Data-Driven Based Procedure for Estimation of Nodal Voltage Phasors in Power Distribution Networks Using a Limited Number of Measured Data
Authors: Barukčić Marinko , Varga Toni , Jerković Štil Vedrana , Benšić Tin
Published: February 2021

The paper studies the framework for the application of computational intelligence methods used for estimations in the distribution power system when a decreased number of measured data is present. Due to the lack of all measured data, the estimation of the distribution power system state is very challenging. The paper studies the application of the artificial neural network and metaheuristic optimization in synergy to solve the voltage phasors estimation problem. The proposed method uses a metaheuristic optimization technique to find virtual input data for the physical model of the network. The presented framework is based on the usage of different computational tools in co-simulation configuration. The research output is the proposed co-simulation setup for the estimation in the distribution power system using a decreased and limited number of available measured data. The estimation procedure was applied on four test distribution networks to validate the presented approach. The maximal estimation errors in voltage magnitudes and angles, using the proposed setup, are below 1.75% and 1∘, respectively, without considering the measurement errors. When the measurement errors are taken into account, the proposed procedure estimates voltage magnitudes and angles with errors below 2.5% and 1.4∘, respectively. In the scenario considering the consumers’ load shape, including the uncertainty range of 20%, the maximal estimation errors are below 1% for magnitude and 0.45∘ for the angle taking the measurement errors in the range of 2% into account.
Give Yourself Permission to Rest
Authors: Gray Kareema J. , Brooks Latoya B.
Published: February 2021

Black women in higher education have always been under pressure to prove that they belong in their positions, and often have taken on more work to prove this. The events of 2020—the COVID-19 global pandemic and the racial and social unrest that swept through the country increased this pressure on Black women in higher education. Historically, Black women have taken on the roles of mother, professional, and caretaker of all who were around them. The events of 2020 added to those roles for Black women faculty, working from home, homeschooling online, checking on the welfare of students, and addressing the emotional needs of their families who have been stuck indoors for months. Self-care is more important now more than before for Black women faculty. To employ these self-care strategies, Black women faculty must first give themselves permission to need them.
The Most Widely Disseminated COVID-19-Related Scientific Publications in Online Media: A Bibliometric Analysis of the Top 100 Articles with the Highest Altmetric Attention Scores
Authors: Moon Ji Yoon , Yoon Dae Young , Hong Ji Hyun , Lim Kyoung Ja , Baek Sora , Seo Young Lan , Yun Eun Joo
Published: February 2021

The novel coronavirus disease 2019 (COVID-19) is a global pandemic. This study’s aim was to identify and characterize the top 100 COVID-19-related scientific publications, which had received the highest Altmetric Attention Scores (AASs). Hence, we searched Altmetric Explorer using search terms such as “COVID” or “COVID-19” or “Coronavirus” or “SARS-CoV-2” or “nCoV” and then selected the top 100 articles with the highest AASs. For each article identified, we extracted the following information: the overall AAS, publishing journal, journal impact factor (IF), date of publication, language, country of origin, document type, main topic, and accessibility. The top 100 articles most frequently were published in journals with high (>10.0) IF (n = 67), were published between March and July 2020 (n = 67), were written in English (n = 100), originated in the United States (n = 45), were original articles (n = 59), dealt with treatment and clinical manifestations (n = 33), and had open access (n = 98). Our study provides important information pertaining to the dissemination of scientific knowledge about COVID-19 in online media.
Relationship between Active Aging and Quality of Life in Middle-Aged and Older Koreans: Analysis of the 2013–2018 KNHANES
Authors: Eum MiJung , Kim HyungSeon
Published: February 2021

With the increase in the aging population worldwide, social interest in having a vibrant and valuable old age has been increasing with changes in the perspectives on old age. This study aimed to determine the relationship between active aging and health-related quality of life (HRQOL) in middle-aged and older Korean using national data. The subjects were 14,117 adults aged ≥55 years. HRQOL was evaluated using the EuroQol–5 Dimension (EQ-5D) questionnaire, and active aging was defined based on the health factors, participation factors, and security factors. The average EQ-5D score was 91.04 ± 0.143. Hierarchical multiple regression analysis sequentially inputting the health, participation, and security factors showed that health factors had the strongest influence on HRQOL (F = 216.656, p < 0.001). In the final model, which included all variables, activity limit (B = −10.477, p < 0.001) and subjective health status (B = −7.282, p < 0.001) were closely related to the HRQOL. In addition, economic activity, income level, home ownership, private health insurance, and unmet healthcare needs were associated with HRQOL. The R2 of the model was 38.2%. To improve the HRQOL of middle-aged and older people, it is necessary to consider active aging factors. Furthermore, follow-up studies using various indicators reflecting active aging should be conducted.
Higher Temperatures Decrease Fruit Size in Strawberry Growing in the Subtropics
Authors: Menzel Christopher
Published: February 2021

Five strawberry (Fragaria × ananassa Duch.) cultivars were grown in Queensland, Australia to determine whether higher temperatures affect production. Transplants were planted on 29 April and data collected on growth, marketable yield, fruit weight and the incidence of small fruit less than 12 g until 28 October. Additional data were collected on fruit soluble solids content (SSC) and titratable acidity (TA) from 16 September to 28 October. Minimum temperatures were 2 °C to 4 °C higher than the long-term averages from 1965 to 1990. Changes in marketable yield followed a dose-logistic pattern (p < 0.001, R2s = 0.99). There was a strong negative relationship between fruit weight (marketable) and the average daily mean temperature in the four or seven weeks before harvest from 29 July to 28 October (p < 0.001, R2s = 0.90). There were no significant relationships between SSC and TA, and temperatures in the eight days before harvest from 16 September to 28 October (p > 0.05). The plants continued to produce a marketable crop towards the end of the season, but the fruit were small and more expensive to harvest. Higher temperatures in the future are likely to affect the economics of strawberry production in subtropical locations.
A Zonal Displacement Approach via Grid Point Weighting in Building Generalization
Authors: Sahbaz Kadir , Basaraner Melih
Published: February 2021

When generalizing a group of objects, displacement is an essential operation to resolve the conflicts arising between them due to enlargement of their symbol sizes and reduction of available map space. Although there are many displacement methods, most of them are rather complicated. Therefore, more practical methods are still needed. In this article, a new building displacement approach is proposed. For this purpose, buildings are grouped and zones are created for them in the blocks via Voronoi tessellation and buffering. Linear patterns are then detected through buffer analyses and the respective zones are narrowed to be able to preserve these patterns. After all the buildings are displaced inside their zones, grid points are generated and then weighted through kernel density estimation and buffer analyses to find suitable locations. Accordingly, the buildings are displaced toward the computed locations iteratively. The proposed approach directly enforces minimum distance and positional accuracy constraints while several indirect mechanisms are used for preserving spatial patterns and relationships. For the quality evaluation of the displacement, the angle, length and shape comparison measures are introduced, computed based on the (Delaunay) triangles or the azimuth comparison measure of the connection lines, generated for the buildings. The quality evaluation criteria are yielded according to the visual assessment of the displacement quality and the quantitative analysis of the measures. The findings demonstrate that the proposed approach is quite effective and practical for zonal building displacement.
Remote Sensing Image Change Detection Using Superpixel Cosegmentation
Authors: Zhu Ling , Zhang Jingyi , Sun Yang
Published: February 2021

The application of cosegmentation in remote sensing image change detection can effectively overcome the salt and pepper phenomenon and generate multitemporal changing objects with consistent boundaries. Cosegmentation considers the image information, such as spectrum and texture, and mines the spatial neighborhood information between pixels. However, each pixel in the minimum cut/maximum flow algorithm for cosegmentation change detection is regarded as a node in the network flow diagram. This condition leads to a direct correlation between computation times and the number of nodes and edges in the diagram. It requires a large amount of computation and consumes excessive time for change detection of large areas. A superpixel segmentation method is combined into cosegmentation to solve this shortcoming. Simple linear iterative clustering is adopted to group pixels by using the similarity of features among pixels. Two-phase superpixels are overlaid to form the multitemporal consistent superpixel segmentation. Each superpixel block is regarded as a node for cosegmentation change detection, so as to reduce the number of nodes in the network flow diagram constructed by minimum cut/maximum flow. In this study, the Chinese GF-1 and Landsat satellite images are taken as examples, the overall accuracy of the change detection results is above 0.80, and the calculation time is only one-fifth of the original.
Spinal Cord Morphology in Degenerative Cervical Myelopathy Patients; Assessing Key Morphological Characteristics Using Machine Vision Tools
Authors: Ost Kalum , Jacobs W. Bradley , Evaniew Nathan , Cohen-Adad Julien , Anderson David , Cadotte David W.
Published: February 2021

Despite Degenerative Cervical Myelopathy (DCM) being the most common form of spinal cord injury, effective methods to evaluate patients for its presence and severity are only starting to appear. Evaluation of patient images, while fast, is often unreliable; the pathology of DCM is complex, and clinicians often have difficulty predicting patient prognosis. Automated tools, such as the Spinal Cord Toolbox (SCT), show promise, but remain in the early stages of development. To evaluate the current state of an SCT automated process, we applied it to MR imaging records from 328 DCM patients, using the modified Japanese Orthopedic Associate scale as a measure of DCM severity. We found that the metrics extracted from these automated methods are insufficient to reliably predict disease severity. Such automated processes showed potential, however, by highlighting trends and barriers which future analyses could, with time, overcome. This, paired with findings from other studies with similar processes, suggests that additional non-imaging metrics could be added to achieve diagnostically relevant predictions. Although modeling techniques such as these are still in their infancy, future models of DCM severity could greatly improve automated clinical diagnosis, communications with patients, and patient outcomes.
Treatment-Resistant Depression Revisited: A Glimmer of Hope
Authors: Halaris Angelos , Sohl Emilie , Whitham Elizabeth A.
Published: February 2021

Major Depressive Disorder (MDD) is a highly prevalent psychiatric disorder worldwide. It causes individual suffering, loss of productivity, increased health care costs and high suicide risk. Current pharmacologic interventions fail to produce at least partial response to approximately one third of these patients, and remission is obtained in approximately 30% of patients. This is known as Treatment-Resistant Depression (TRD). The burden of TRD exponentially increases the longer it persists, with a higher risk of impaired functional and social functioning, vast losses in quality of life and significant risk of somatic morbidity and suicidality. Different approaches have been suggested and utilized, but the results have not been encouraging. In this review article, we present new approaches to identify and correct potential causes of TRD, thereby reducing its prevalence and with it the overall burden of this disease entity. We will address potential contributory factors to TRD, most of which can be investigated in many laboratories as routine tests. We discuss endocrinological aberrations, notably, hypothalamic-pituitary-adrenal (HPA) axis dysregulation and thyroid and gonadal dysfunction. We address the role of Vitamin D in contributing to depression. Pharmacogenomic testing is being increasingly used to determine Single Nucleotide Polymorphisms in Cytochrome P450, Serotonin Transporter, COMT, folic acid conversion (MTHFR). As the role of immune system dysregulation is being recognized as potentially a major contributory factor to TRD, the measurement of C-reactive protein (CRP) and select immune biomarkers, where testing is available, can guide combination treatments with anti-inflammatory agents (e.g., selective COX-2 inhibitors) reversing treatment resistance. We focus on established and emerging test procedures, potential biomarkers and non-biologic assessments and interventions to apply personalized medicine to effectively manage treatment resistance in general and TRD specifically.
Invasive Ductal Breast Cancer with Osteoclast-Like Giant Cells: A Case Report Based on the Gene Expression Profile for Changes in Management
Authors: Irelli Azzurra , Sirufo Maria Maddalena , Quaglione Gina Rosaria , De Pietro Francesca , Bassino Enrica Maria , D’Ugo Carlo , Ginaldi Lia , De Martinis Massimo
Published: February 2021

We report the case of a 49-year-old woman diagnosed with a rare histotype of early breast cancer (BC), invasive ductal carcinoma with osteoclast-like giant cells (OGCs), from the perspective of gene profile analysis tests. The patient underwent a quadrantectomy of the right breast with removal of 2 cm neoplastic nodule and three ipsilateral sentinel lymph nodes. The Oncotype Dx gave a recurrence score (RS) of 23, and taking into account the patient’s age, an RS of 23 corresponds to a chemotherapy benefit of 6.5%. After a multidisciplinary collegial discussion, and in consideration of the patient’s age, the absence of comorbidity, the premenopausal state, the rare histotype and the Oncotype Dx report, the patient was offered adjuvant chemotherapy treatment followed by hormone therapy. This case may be an example of the utility of integrating gene expression profiling tests into clinical practice in the adjuvant treatment decision of a rare histotype BC. The Oncotype Dx test required to supplement the histological examination made us opt for the proposal of a combined treatment of adjuvant chemotherapy followed by adjuvant hormone therapy. It demonstrates the importance of considering molecular tests and, in particular, the Oncotype Dx, in estimating the risk of disease recovery at 10 years in order to identify patients who benefit from hormone therapy alone versus those who benefit from the addition of chemotherapy, all with a view toward patient-centered oncology. Here, we discuss the possible validity and limitations of the Oncotype Dx in a rare luminal A-like histotype with high infiltrate of stromal/inflammatory cells.
How Diet-Induced Changes in the “Gut-Liver” Axis Affect Chronic Liver Disease Outcome?
Authors: Koumbi Lemonica , Eliopoulos Aristides G. , Vassilopoulou Emilia
Published: February 2021

Hepatocellular carcinoma (HCC) occurs in patients with chronic liver damage, inflammation and cirrhosis. The facilitators involved in increasing the HCC risk in the damaged liver are yet to be discovered. Diet and lifestyle have a profound effect on the liver inflammation and HCC. The term “gut liver axis” describes the bidirectional relationship between the liver and the gut, which are both anatomically and functionally related. Chronic liver damage is characterised by increased intestinal permeability that allows the translocation of various components and metabolites from the gut microbiota to the liver, resulting in liver inflammation and fibrosis. In this review, we discuss how diet-induced changes in gut microbiome composition, such as lipopolysaccharide and lipoteichoic acid, and its metabolites, such as bile acids, play a role in the pathogenesis of liver fibrosis and HCC.
Magneto-Structural Relationship of Tetragonally-Compressed Octahedral Iron(II) Complex Surrounded by a pseudo-S6 Symmetric Hexakis-Dimethylsulfoxide Environment
Authors: Sakiyama Hiroshi , Abiko Takaaki , Koikawa Masayuki , Yamasaki Mikio
Published: February 2021

Since the octahedral high-spin iron(II) complex has the 5T2g ground term, the spin-orbit coupling should be considered in magnetic analysis; however, such treatment is rarely seen in recent papers, although the symmetry-sensitive property is of interest to investigate in detail. A method to consider the T-term magnetism was well constructed more than half a century ago. On the other hand, the method has been still improved in recent years. In this study, the octahedral high-spin iron(II) complex [Fe(dmso)6][BPh4]2 (dmso: dimethylsulfoxide) was newly prepared, and the single-crystal X-ray diffraction method revealed the tetragonal compression of the D4-symmetric coordination geometry around the iron(II) ion and the pseudo-S6 hexakis-dmso environment. From the magnetic data, the sign of the axial splitting parameter, Δ, was found to be negative, indicating the 5E ground state in the D4 symmetry. The DFT computation showed the electronic configuration of (dxz)2(dx2−y2)1(dyz)1(dxy)1(dz2)1 due to the tetragonal compression and the pseudo-S6 environment of dmso π orbitals. The electronic configuration corresponded to the 5E ground term, which was in agreement with the negative Δ value. Therefore, the structurally predicted ground state was consistent with the estimation from the magnetic measurements.
On the Paired-Domination Subdivision Number of a Graph
Authors: Hao Guoliang , Sheikholeslami Seyed Mahmoud , Chellali Mustapha , Khoeilar Rana , Karami Hossein
Published: February 2021

In order to increase the paired-domination number of a graph G, the minimum number of edges that must be subdivided (where each edge in G can be subdivided no more than once) is called the paired-domination subdivision number sdγpr(G) of G. It is well known that sdγpr(G+e) can be smaller or larger than sdγpr(G) for some edge e∉E(G). In this note, we show that, if G is an isolated-free graph different from mK2, then, for every edge e∉E(G), sdγpr(G+e)≤sdγpr(G)+2Δ(G).
A Novel Geometric Modeling and Calculation Method for Forward Displacement Analysis of 6-3 Stewart Platforms
Authors: Zhu Ganmin , Wei Shimin , Zhang Ying , Liao Qizheng
Published: February 2021

A novel geometric modeling and calculation method for forward displacement analysis of the 6-3 Stewart platforms is proposed by using the conformal geometric algebra (CGA) framework. Firstly, two formulas between 2-blade and 1-blade are formulated. Secondly, the expressions for two spherical joints of the moving platform are given via CGA operation. Thirdly, a coordinate-invariant geometric constraint equation is deduced. Fourthly, a 16-degree univariate polynomial equation without algebraic elimination by using the Euler angle substitution is presented. Fifthly, the coordinates of three spherical joints on the moving platform are calculated without judging the radical symbols. Finally, two numerical examples are used to verify the method. The highlight of this paper is that a new geometric modeling and calculation method without algebraic elimination is obtained by using the determinant form of the CGA inner product algorithm, which provides a new idea to solve a more complex spatial parallel mechanism in the future.
Refinements of Hermite–Hadamard Inequalities for Continuous Convex Functions via (p,q)-Calculus
Authors: Prabseang Julalak , Nonlaopon Kamsing , Tariboon Jessada , Ntouyas Sotiris K.
Published: February 2021

In this paper, we present some new refinements of Hermite–Hadamard inequalities for continuous convex functions by using (p,q)-calculus. Moreover, we study some new (p,q)-Hermite–Hadamard inequalities for multiple integrals. Many results given in this paper provide extensions of others given in previous research.
A Full Description of ω-Limit Sets of Cournot Maps Having Non-Empty Interior and Some Economic Applications
Authors: Linero-Bas Antonio , Muñoz-Guillermo María
Published: February 2021

Given a continuous Cournot map F(x,y)=(f2(y),f1(x)) defined from I2=[0,1]×[0,1] into itself, we give a full description of its ω-limit sets with non-empty interior. Additionally, we present some partial results for the empty interior case. The distribution of the ω-limits with non-empty interior gives information about the dynamics and the possible outputs of each firm in a Cournot model. We present some economic models to illustrate, with examples, the type of ω-limits that appear.
Unified Polynomial Dynamic Programming Algorithms for P-Center Variants in a 2D Pareto Front
Authors: Dupin Nicolas , Nielsen Frank , Talbi El-Ghazali
Published: February 2021

With many efficient solutions for a multi-objective optimization problem, this paper aims to cluster the Pareto Front in a given number of clusters K and to detect isolated points. K-center problems and variants are investigated with a unified formulation considering the discrete and continuous versions, partial K-center problems, and their min-sum-K-radii variants. In dimension three (or upper), this induces NP-hard complexities. In the planar case, common optimality property is proven: non-nested optimal solutions exist. This induces a common dynamic programming algorithm running in polynomial time. Specific improvements hold for some variants, such as K-center problems and min-sum K-radii on a line. When applied to N points and allowing to uncover M<N points, K-center and min-sum-K-radii variants are, respectively, solvable in O(K(M+1)NlogN) and O(K(M+1)N2) time. Such complexity of results allows an efficient straightforward implementation. Parallel implementations can also be designed for a practical speed-up. Their application inside multi-objective heuristics is discussed to archive partial Pareto fronts, with a special interest in partial clustering variants.
Insights into the Influence of Membrane Permeability and Structure on Osmotically-Driven Membrane Processes
Authors: Wei Jing , She Qianhong , Liu Xin
Published: February 2021

The success of osmotically-driven membrane (OM) technology relies critically on high-performance membranes. Yet trade-off of membrane properties, often further complicated by the strongly non-linear dependence of OM performance on them, imposes important constraint on membrane performance. This work systematically characterized four typical commercial osmotic membranes in terms of intrinsic separation parameters, structure and surface properties. The osmotic separation performance and membrane scaling behavior of these membranes were evaluated to elucidate the interrelationship of these properties. Experimental results revealed that membranes with smaller structural parameter (S) and higher water/solute selectivity underwent lower internal concentration polarization (ICP) and exhibited higher forward osmosis (FO) efficiency (i.e., higher ratio of experimental water flux over theoretical water flux). Under the condition with low ICP, membrane water permeability (A) had dominant effect on water flux. In this case, the investigated thin film composite membrane (TFC, A = 2.56 L/(m2 h bar), S = 1.14 mm) achieved a water flux up to 82% higher than that of the asymmetric cellulose triacetate membrane (CTA-W(P), A = 1.06 L/(m2 h bar), S = 0.73 mm). In contrast, water flux became less dependent on the A value but was affected more by membrane structure under the condition with severe ICP, and the membrane exhibited lower FO efficiency. The ratio of water flux (Jv TFC/Jv CTA-W(P)) decreased to 0.55 when 0.5 M NaCl feed solution and 2 M NaCl draw solution were used. A framework was proposed to evaluate the governing factors under different conditions and to provide insights into the membrane optimization for targeted OM applications.
Membrane Protein Stabilization Strategies for Structural and Functional Studies
Authors: Errasti-Murugarren Ekaitz , Bartoccioni Paola , Palacín Manuel
Published: February 2021

Accounting for nearly two-thirds of known druggable targets, membrane proteins are highly relevant for cell physiology and pharmacology. In this regard, the structural determination of pharmacologically relevant targets would facilitate the intelligent design of new drugs. The structural biology of membrane proteins is a field experiencing significant growth as a result of the development of new strategies for structure determination. However, membrane protein preparation for structural studies continues to be a limiting step in many cases due to the inherent instability of these molecules in non-native membrane environments. This review describes the approaches that have been developed to improve membrane protein stability. Membrane protein mutagenesis, detergent selection, lipid membrane mimics, antibodies, and ligands are described in this review as approaches to facilitate the production of purified and stable membrane proteins of interest for structural and functional studies.
Fatigue Models Based on Real Load Spectra and Corrected S-N Curve for Estimating the Residual Service Life of the Remanufactured Excavator Beam
Authors: Zhao Gang , Xiao Junsong , Zhou Qi
Published: February 2021

To more accurately predict the residual fatigue cycles and estimate the service life of the remanufactured excavator, the fatigue models integrating the corrected S-N curve, the RFC algorithm, the FEA model, and the mechanism dynamic model are established depending on the real load spectra under experimental working conditions and the corrected S-N curve of the beam metal remanufactured with the welding process. Depending on the test data of the unidirectional stress history and the servo displacements of the major cylinders, the mechanism dynamic model was first established to illustrate the real load spectra applied on the pivots of the working beam. The load spectra are further used in the finite element analysis (FEA) model to obtain the stress contours of the beam relevant to the sampling time, which is the stress spectra at any nodes on the beam in theory. Subsequently, the rain flow counting (RFC) algorithm based on the dual parameters of the cyclic stress amplitude and mean is established to provide the frequency spectra in the longevity region on the beam. Furthermore, due to the fatigue property changes of the beam metal remanufactured with the welding process, its S-N curve is corrected based on the detail fatigue rating (DFR) method to compute the stress cycles at each stress level on the crisis nodes. Finally, the total stress cycles that can be burdened by the remanufactured beam is computed under the Miner’s linear fatigue cumulative criterion. The total number of stress cycles is eventually converted to the fatigue and service life depending on the proportion of the sampling time under relevant working conditions. The results show that integrated fatigue models provide a practical approach to enhancing the accuracy of the estimation on the residual service life of the remanufactured excavator beam. It is significant for improving the reliability and safety of the remanufactured excavator.
Laser Surface Modification in Ti-xNb-yMo Alloys Prepared by Powder Metallurgy
Authors: Tendero Inmaculada , Rossi Mariana Correa , Viera Mauricio , Amado José Manuel , Tobar María José , Vicente Ángel , Yañez Armando , Amigó Vicente
Published: February 2021

The main objective was to study the effect of surface modification by laser on Ti-Nb-Mo powder metallurgical alloys to improve their mechano-chemical behavior and their application as a biomedical implant. The used powder mixtures were produced in an inert atmosphere. Uniaxial compaction took place at 600 MPa with high-vacuum sintering at 1250 °C for 3 h. The specimens for the three-point flexure test were prepared and their mechanical properties determined. Microstructural characterization was performed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) to obtain the distribution of phases, porosity, size, and shape of the grains of each alloy. Corrosion behavior was evaluated by electrochemical tests using an artificial saliva electrolyte modified from Fusayama at 37 °C. Chemical characterization was completed by analyzing the ionic release by Inductively coupled plasma atomic emission spectroscopy (ICP-EOS) after immersion for 730 h in Fusayama solution modified with NaF at 37 °C to simulate a 20-year life span based on a daily 2-min cycle of three toothbrushes. Corrosion behavior confirmed promising possibilities for the biomedicine field. The surface porosity of the samples not submitted to surface treatment deteriorated properties against corrosion and ion release. The obtained phase was β, with a low α”-martensite percentage. The maximum resistance to bending was greater after surface fusion. Plastic deformations were above 7% under some conditions. Microhardness came close to 300 HV in heat-affected zone (HAZ) and 350 HV in fusion zone (FZ) (under the determined condition. The elastic modulus lowered by around 10%. The corrosion rate was lower in Ti-27Nb-8Mo and Ti-35Nb-6Mo. Niobium release was significant, but below the physiological limit.
Microstructure and Properties of a Novel Al-Mg-Si Alloy AA 6086
Authors: Zupanič Franc , Steinacher Matej , Žist Sandi , Bončina Tonica
Published: February 2021

In this work, we investigated a novel Al-Mg-Si alloy, which was developed from an AA 6082, in order to considerably improve the yield and tensile strengths whilst retain excellent ductility. The new alloy possesses a higher content of Si than specified by AA 6082, and, in addition, it contains copper and zirconium. The alloy was characterized in the as-cast condition, after homogenization, extrusion, and T6 heat treatment using light microscopy, scanning and transmission electron microscopy with energy dispersive spectrometry, X-ray diffraction, differential thermal analysis and tensile testing. After T6 temper, tensile strengths were around 490 MPa with more than 10% elongation at fracture. The microstructure consisted of small-grained Al-rich matrix with α-AlMnSi and Al3Zr dispersoids, and Q′-AlCuMgSi and β-Mg2Si-type precipitates.
Effect of Side Blowing on Fluid Flow and Mixing Phenomenon in Gas-Stirred Ladle
Authors: Cheng Rong , Zhang Liangjin , Yin Yanbin , Zhang Jiongming
Published: February 2021

To investigate the gas agitation characteristics of side blowing, the fluid flow and mixing phenomenon in a 1:3 scale model ladle of a 150 t industrial gas-stirred ladle with bottom and side plugs were studied by using physical and numerical modelings together. Side blowing enhanced the horizontal flow of water in the model ladle. Compared with bottom blowing, side blowing that is close to the ladle bottom with more than two plugs increases the average velocity of water, which represents the agitation power, improves the uniformity of water velocity distribution, reduces the stagnant region rate, and shortens the mixing time. The mixing time of dual bottom plugs is almost 1.5 times of that of four side plugs at 116 mm under the same flow rate. The mixing time is not only influenced by the agitation power but also by the uniformity of water velocity distribution. Although the agitation power of four side plugs at 450 mm under the flow rate of 1.8 m3/h is about 1.5 times of that at 116 mm with 0.6 m3/h. The mixing time of the 1.8 m3/h flow rate is about 1.2 times of that of the 0.6 m3/h because of the different water velocity distributions.
Combining Differential Scanning Calorimetry and Cooling-Heating Curve Thermal Analysis to Study the Melting and Solidification Behavior of Al-Ce Binary Alloys
Authors: Aniolek Marta , Smith Tyler , Czerwinski Frank
Published: February 2021

Two common techniques of thermal analysis, Differential Scanning Calorimetry (DSC) and Cooling/Heating Curve Thermal Analysis (CCTA), based on different signal collected and utilizing samples with a weight difference of three orders of magnitude, were used to assess the solidification and melting behavior of Al-Ce binary alloys, containing from 5 to 20 wt. % Ce. Thermal analysis was accompanied by microscopic observations of solidified structures. For heating/cooling rates of 0.2–0.4 °C/s, temperatures of eutectic transformation L ↔ Al + Al11Ce3 in the Al-10Ce alloy along with additional proeutectic reactions L ↔ Al in the Al-5Ce hypoeutectic alloy and L ↔ Al11Ce3 in Al-15Ce and Al-20Ce hypereutectic alloys, were determined. Although there was a general agreement in major transformations, registered by DSC and CCTA during melting and solidification, differences in the reaction temperature determined exceeded the typical measurement errors for each technique. In addition, DSC and CCTA exhibited differences in detecting some proeutectic reactions and minor non-equilibrium effects, accompanying the eutectic transformation. Some factors that could contribute to differences observed and their implications for engineering practice were discussed.
Impact of Altered Gut Microbiota and Its Metabolites in Cystic Fibrosis
Authors: Thavamani Aravind , Salem Iman , Sferra Thomas J. , Sankararaman Senthilkumar
Published: February 2021

Cystic fibrosis (CF) is the most common lethal, multisystemic genetic disorder in Caucasians. Mutations in the gene encoding the cystic fibrosis transmembrane regulator (CFTR) protein are responsible for impairment of epithelial anionic transport, leading to impaired fluid regulation and pH imbalance across multiple organs. Gastrointestinal (GI) manifestations in CF may begin in utero and continue throughout the life, resulting in a chronic state of an altered intestinal milieu. Inherent dysfunction of CFTR leads to dysbiosis of the gut. This state of dysbiosis is further perpetuated by acquired factors such as use of antibiotics for recurrent pulmonary exacerbations. Since the gastrointestinal microbiome and their metabolites play a vital role in nutrition, metabolic, inflammatory, and immune functions, the gut dysbiosis will in turn impact various manifestations of CF—both GI and extra-GI. This review focuses on the consequences of gut dysbiosis and its metabolic implications on CF disease and possible ways to restore homeostasis.
Metabolomics of Cerebrospinal Fluid from Healthy Subjects Reveal Metabolites Associated with Ageing
Authors: Carlsson Henrik , Rollborn Niclas , Herman Stephanie , Freyhult Eva , Svenningsson Anders , Burman Joachim , Kultima Kim
Published: February 2021

To increase our understanding of age-related diseases affecting the central nervous system (CNS) it is important to understand the molecular processes of biological ageing. Metabolomics of cerebrospinal fluid (CSF) is a promising methodology to increase our understanding of naturally occurring processes of ageing of the brain and CNS that could be reflected in CSF. In the present study the CSF metabolomes of healthy subjects aged 30–74 years (n = 23) were studied using liquid chromatography high-resolution mass spectrometry (LC-HRMS), and investigated in relation to age. Ten metabolites were identified with high confidence as significantly associated with ageing, eight with increasing levels with ageing: isoleucine, acetylcarnitine, pipecolate, methionine, glutarylcarnitine, 5-hydroxytryptophan, ketoleucine, and hippurate; and two decreasing with ageing: methylthioadenosine and 3-methyladenine. To our knowledge, this is the first time the CSF metabolomes of healthy subjects are assessed in relation to ageing. The present study contributes to the field of ageing metabolomics by presenting a number of metabolites present in CSF with potential relevance for ageing and the results motivate further studies.
Behavioral and Metabolome Differences between C57BL/6 and DBA/2 Mouse Strains: Implications for Their Use as Models for Depression- and Anxiety-Like Phenotypes
Authors: Filiou Michaela D. , Nussbaumer Markus , Teplytska Larysa , Turck Christoph W.
Published: February 2021

Mouse models are widely used to study behavioral phenotypes related to neuropsychiatric disorders. However, different mouse strains vary in their inherent behavioral and molecular characteristics, which needs to be taken into account depending on the nature of the study. Here, we performed a detailed behavioral and molecular comparison of C57BL/6 (B6) and DBA/2 (DBA) mice, two inbred strains commonly used in neuropsychiatric research. We analyzed anxiety-related and depression-like traits, quantified hippocampal and plasma metabolite profiles, and assessed total antioxidant capacity (ΤAC). B6 mice exhibit increased depression-like and decreased anxiety-related behavior compared to DBA mice. Metabolite level differences indicate alterations in amino acid, nucleotide and mitochondrial metabolism that are accompanied by a decreased TAC in B6 compared to DBA mice. Our data reveal multiple behavioral and molecular differences between B6 and DBA mouse strains, which should be considered in the experimental design for phenotype, pharmacological and mechanistic studies relevant for neuropsychiatric disorders.
Dysbiosis in Pediatrics Is Associated with Respiratory Infections: Is There a Place for Bacterial-Derived Products?
Authors: Ballarini Stefania , Rossi Giovanni A. , Principi Nicola , Esposito Susanna
Published: February 2021

Respiratory tract infections (RTIs) are common in childhood because of the physiologic immaturity of the immune system, a microbial community under development in addition to other genetic, physiological, environmental and social factors. RTIs tend to recur and severe lower viral RTIs in early childhood are not uncommon and are associated with increased risk of respiratory disorders later in life, including recurrent wheezing and asthma. Therefore, a better understanding of the main players and mechanisms involved in respiratory morbidity is necessary for a prompt and improved care as well as for primary prevention. The inter-talks between human immune components and microbiota as well as their main functions have been recently unraveled; nevertheless, more is still to be discovered or understood in the above medical conditions. The aim of this review paper is to provide the most up-to-date overview on dysbiosis in pre-school children and its association with RTIs and their complications. The potential role of non-harmful bacterial-derived products, according to the old hygiene hypothesis and the most recent trained-innate immunity concept, will be discussed together with the need of proof-of-concept studies and larger clinical trials with immunological and microbiological endpoints.