bluuebunny/crossref_metadata_2025 huggingface dataset:
Unveiling the binding mode of perfluorooctanoic acid to human serum albumin
Authors: Maso Lorenzo , Trande Matteo , Liberi Stefano , Moro Giulia , Daems Elise , Linciano Sara , Sobott Frank , Covaceuszach Sonia , Cassetta Alberto , Fasolato Silvano , Moretto Ligia M. , De Wael Karolien , Cendron Laura , Angelini Alessandro
Published: February 2021

Perfluorooctanoic acid (PFOA) is a toxic compound that is absorbed and distributed throughout the body by noncovalent binding to serum proteins such as human serum albumin (hSA). Though the interaction between PFOA and hSA has been already assessed using various analytical techniques, a high resolution and detailed analysis of the binding mode is still lacking. We report here the crystal structure of hSA in complex with PFOA and a medium‐chain saturated fatty acid (FA). A total of eight distinct binding sites, four occupied by PFOAs and four by FAs, have been identified. In solution binding studies confirmed the 4:1 PFOA‐hSA stoichiometry and revealed the presence of one high and three low affinity binding sites. Competition experiments with known hSA‐binding drugs allowed locating the high affinity binding site in sub‐domain IIIA. The elucidation of the molecular basis of the interaction between PFOA and hSA might provide not only a better assessment of the absorption and elimination mechanisms of these compounds in vivo but also have implications for the development of novel molecular receptors for diagnostic and biotechnological applications.
Effect of mitoquinone on liver metabolism and steatosis in obese and diabetic rats
Authors: Fink Brian D. , Yu Liping , Coppey Lawrence , Obrosov Alexander , Shevalye Hanna , Kerns Robert J. , Yorek Mark A. , Sivitz William I.
Published: February 2021

Previous work by ourselves and others showed that mitoquinone (mitoQ) reduced oxidative damage and prevented hepatic fat accumulation in mice made obese with high‐fat (HF) feeding. Here we extended these studies to examine the effect of mitoQ on parameters affecting liver function in rats treated with HF to induce obesity and in rats treated with HF plus streptozotocin (STZ) to model a severe form of type 2 diabetes. In prior reported work, we found that mitoQ significantly improved glycemia based on glucose tolerance data in HF rats but not in the diabetic rats. Here we found only non‐significant reductions in insulin and glucose measured in the fed state at sacrifice in the HF mice treated with mitoQ. Metabolomic data showed that mitoQ altered several hepatic metabolic pathways in HF‐fed obese rats toward those observed in control normal chow‐fed non‐obese rats. However, mitoQ had little effect on pathways observed in the diabetic rats, wherein diabetes itself induced marked pathway aberrations. MitoQ did not alter respiration or membrane potential in isolated liver mitochondria. MitoQ reduced liver fat and liver hydroperoxide levels but did not improve liver function as marked by circulating levels of aspartate and alanine aminotransferase (ALT). In summary, our results for HF‐fed rats are consistent with past findings in HF‐fed mice indicating decreased liver lipid hydroperoxides (LPO) and improved glycemia. However, in contrast to the HF obese mice, mitoQ did not improve glycemia or reset perturbed metabolic pathways in the diabetic rats.
Evaluation of fluopyram for management of Meloidogyne ethiopica and migratory nematodes in commercial tomato greenhouses in the Metropolitan Region of Chile
Authors: Meza Pablo , Elgueta Sebastián , Sagredo Boris
Published: February 2021

BACKGROUND

The nematicidal effects of fluopyram were evaluated for the suppression of Meloidogyne ethiopica and migratory nematodes, Xiphinema americanum s. l., Hemicycliophora spp. and Pratylenchus spp., in two commercial tomato greenhouses in Chile. The effects of fluopyram on plant‐parasitic nematodes, plant vigor and fruit yield were determined.

RESULTS

Fluopyram demonstrated good potential for the management of M. ethiopica and migratory nematodes, especially during the early stages of evaluation (30–60 days after planting). There were also improvements in vigor of treated plants. A general trend in improved fruit quality was also observed, however, no significant differences in total yield were found between treatments.

CONCLUSIONS

Our study is one of the first evaluations of fluopyram under field conditions against M. ethiopica. The findings suggest that this new nematicide has good potential for the management of M. ethiopica and some migratory nematodes in tomatoes cropped in greenhouses in the Metropolitan Region of Chile.

© 2021 Society of Chemical Industry
The effect of structural modification of antimicrobial peptides on their antimicrobial activity, hemolytic activity, and plasma stability
Authors: Wang Taoran , Zou Cunbin , Wen Na , Liu Xingdong , Meng Zhao , Feng Siliang , Zheng Zhibing , Meng Qingbin , Wang Chenhong
Published: February 2021

In this article, a series of modifications were made on an antimicrobial peptide F2,5,12W, including altering the amino acid sequence, introducing cysteine and other typical amino acids, developing peptide dimers via disulfide bonds, and conjugating with mPEG, in order to enhance the antimicrobial activity, plasma stability, and reduce the hemolytic activity of peptides. The results showed that mPEG conjugation could significantly improve the plasma stability and reduce the hemolytic activity of peptides, while the antimicrobial activity decreased meanwhile. However, altering the sequence of the peptide without changing its amino acid composition had little impact on its antimicrobial activity and plasma stability. The introduction of cysteine enhanced the plasma stability of peptides conspicuously, but at the same time, the increased hydrophobicity of peptides increased their hemolysis. The antimicrobial mechanism and cytotoxicity of the peptides with relatively high antimicrobial activity were also studied. In general, this study provided some ideas for the rational design and structure optimization of antimicrobial peptides.
Grassland conversion to croplands impacted soil pore parameters measured via X‐ray computed tomography
Authors: Singh Navdeep , Kumar Sandeep , Udawatta Ranjith P. , Anderson Stephen H. , de Jonge Lis W. , Katuwal Sheela
Published: February 2021

Soil porosity estimated conventionally cannot provide the spatial distribution and geometrical properties of pore networks. This on‐farm study assessed the impacts of grassland–cropland conversion on soil pore characteristics. This study aimed to quantify the microscale changes in pores near the soil surface (0–10 cm) under grasslands converted to croplands managed with a rotation of corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] (CS); an integrated crop–livestock system (ICLS) of corn–soybean–oats (Avena sativa L.)–cover crops (CCs), with livestock grazing on corn and soybean residue after harvest and on CCs; and the native grassland (NG). Intact soil cores (diameter: 76.2 mm; length: 76.2 mm) were collected in three replications from CS, ICLS, and NG areas located adjacent to each other. Soil cores were scanned via X‐ray computed tomography (CT) (pixel resolution: 0.226 by 0.226 mm; slice thickness: 0.5 mm). Soils under CS converted from NG significantly decreased CT‐measured macroporosity eightfold. However, it increased sevenfold when CS was converted to ICLS. Higher connected porosity, connection probability, and macroporosity under ICLS and NG enhanced the saturated hydraulic conductivity (Ksat) compared with CS. The soil organic carbon (SOC) stock was increased by 13% at 0‐ to 10‐cm depth, when soils under CS were converted to improved management (ICLS). Significant correlations of CT‐measured pore parameters were found with Ksat. We conclude that CS converted from grasslands degraded SOC, pores, and other hydro‐physical properties, which can be enhanced by integrating CCs and grazing on CCs and crop residues.
Unsupervised random forests
Authors: Mantero Alejandro , Ishwaran Hemant
Published: February 2021

sidClustering is a new random forests unsupervised machine learning algorithm. The first step in sidClustering involves what is called sidification of the features: staggering the features to have mutually exclusive ranges (called the staggered interaction data [SID] main features) and then forming all pairwise interactions (called the SID interaction features). Then a multivariate random forest (able to handle both continuous and categorical variables) is used to predict the SID main features. We establish uniqueness of sidification and show how multivariate impurity splitting is able to identify clusters. The proposed sidClustering method is adept at finding clusters arising from categorical and continuous variables and retains all the important advantages of random forests. The method is illustrated using simulated and real data as well as two in depth case studies, one from a large multi‐institutional study of esophageal cancer, and the other involving hospital charges for cardiovascular patients.
Hybrid design evaluating new biomarkers when there is an existing screening test
Authors: Park Yeonhee , Yuan Ying , Ning Jing , Liu Suyu , Feng Ziding
Published: February 2021

Development of cancer screening biomarkers usually follows the Early Detection Research Network 5‐Phase guideline in Pepe et al. A key feature of this guide is that the phased development follows a sequential order, moving to the next phase only when the current phase study is complete and has met its target performance. Motivated by a newly funded Newly onset Diabetes cohort study, we propose a design evaluating new biomarkers to discriminate between cases and controls in the presence of an existing screening test. The proposed design achieves two goals: (1) avoiding bias in estimating sensitivity or specificity in predicting cancer at a given time period prior to clinical diagnosis, using data from both screening detected cancers in Phase IV study and clinically diagnosed cancers in Phase III study; and (2) building a panel with biomarkers for Phase III and IV studies based on all data. A simulation study shows that the proposed design outperforms both a conventional method using data in Phase III arm only and a naive method using data in Phase III and IV arms ignoring the difference between the time of screening the detected cancer and the time of clinical diagnosis. The proposed design yields a smaller standard error of the estimation and increases the statistical power to confirm biomarker performance. This proposed method has the potential to shorten the cancer screening biomarker development process, use resources more effectively, and bring benefits to patients quickly.
Sunlight‐Assisted Photocatalytic Sustainable Synthesis of 1,4‐Disubstituted 1,2,3‐Triazoles and Benzimidazoles Using TiO2−Cu2(OH)PO4 Under Solvent‐Free Condition
Authors: Kiranmye Tayyala , Vadivelu Murugan , Magadevan Deviga , Sampath Sugirdha , Parthasarathy Kannabiran , Aman Noor , Karthikeyan Kesavan
Published: February 2021

Herein, we report the facile synthesis of 1,4‐disubstituted 1,2,3‐triazoles and benzimidazoles using TiO2−Cu2(OH)PO4 as an efficient sunlight active nanophotocatalyst under solvent‐free condition. The highlights of the proposed protocol are simple, scalable with a broad substrate scope, short reaction time, excellent regioselectivity and catalyst recyclability. The use of recyclable photocatalyst and solvent‐free condition makes the catalytic system resulted in sustainable and environmental‐friendly procedure.
Facile One‐Pot Synthesis of Magnetic Targeted Polymers for Drug Delivery and Study on Thermal Decomposition Kinetics
Authors: Shi Zhen , Wang Yazhen , Sun Yu , Wu Xueying , Xiao Tianyuan , Dong Shaobo , Lan Tianyu
Published: February 2021

Magnetic targeting materials are the hot topic of research in the current study of targeted drug carrier. However, the complexity of the preparation method has hindered its further development. In this paper, a facile one‐pot strategy was developed to synthesize a novel amphiphilic drug carrier (Fe3O4‐PVA@SH). We determined that Fe3O4‐PVA@SH drug carrier with uniform size and excellent superparamagnetic properties can be fabricated on the simultaneous formation of magnetic Polyvinyl alcohol(PVA) polymer‐linked branches of thiohydrazide‐iminopropyltriethoxysilane (TIPTS) by mixing Fe3O4, PVA, and TIPTS in a DMSO alkaline aqueous solution. The Fe3O4‐PVA@SH drug carrier were subsequently characterised by FTIR, XPS, SEM, EDS, size and VSM. It was found that the drug carrier Fe3O4‐PVA@SH could achieve 83 % aspirin loading and 85 % DOX⋅HCl loading. In vitro simulated drug release experiments showed that Aspirin could achieved 86.9 % at pH 7.2 and DOX⋅HCl could achieved 81.6 % at pH 4.7 for 80 h. Additionally, we measured the thermal stability and enthalpy of thermal decomposition of the Fe3O4‐PVA@SH coupling agent using a differential scanning calorimeter (DSC) and a non‐isothermal decomposition method. This research offers the potential for the industrialization of magnetic drug carriers as a means of increasing its cost‐effectiveness and leveraging magnetic targeted drug carriers for drug delivery and other applications.
Design, Synthesis, and Cholinesterase Inhibitory Activity of 4‐Substituted‐6‐(trihalomethyl)‐2‐methylsulfanyl Pyrimidines
Authors: Da Silva Andreia M. P. W. , Mittersteiner Mateus , Da Silva Fabio M. , D'Avila Fernanda , Nogara Pablo A. , Nogara Karise F. , Rocha João B. T. , Bonacorso Helio G. , Martins Marcos A. P. , Zanatta Nilo
Published: February 2021

A chemoselective approach is reported for the synthesis of 4‐(bromo/chloro)methyl‐2‐methylsulfanyl‐6‐trihalomethyl pyrimidines and subsequent nucleophilic substitution of the halomethyl moiety with aminoalcohols. The final compounds were choline derivatives (bearing a pyrimidine ring). These were tested as AChE and BChE inhibitors, and presented IC50 values in the range of 13.8–81.6 μM. Remarkably, the trichloromethyl pyrimidines were the most active compounds. Docking studies and ADMET properties are also reported.
Substrate Engineering for CVD Growth of Single Crystal Graphene
Authors: Huang Ming , Deng Bangwei , Dong Fan , Zhang Lili , Zhang Zheye , Chen Peng
Published: February 2021

Single crystal graphene (SCG) has attracted enormous attention for its unique potential for next‐generation high‐performance optoelectronics. In the absence of grain boundaries, the exceptional intrinsic properties of graphene are preserved by SCG. Currently, chemical vapor deposition (CVD) has been recognized as an effective method for the large‐scale synthesis of graphene films. However, polycrystalline films are usually obtained and the present grain boundaries compromise the carrier mobility, thermal conductivity, optical properties, and mechanical properties. The scalable and controllable synthesis of SCG is challenging. Recently, much attention has been attracted by the engineering of large‐size single‐crystal substrates for the epitaxial CVD growth of large‐area and high‐quality SCG films. In this article, a comprehensive and comparative review is provided on the selection and preparation of various single‐crystal substrates for CVD growth of SCG under different conditions. The growth mechanisms, current challenges, and future development and perspectives are discussed.
The evolution of democratic tradition and regional variation in resistance in Nazi Germany
Authors: Geerling Wayne , Magee Gary , Smyth Russell
Published: February 2021

Are deep‐rooted democratic traditions related to geographical manifestation of resistance to authoritarian regimes? We address this question by studying the regional pattern of the most serious form of resistance experienced in prewar Nazi Germany, namely, those acts of resistance that resulted in arrest for treason and high treason. Specifically, we examine whether spatial variations in participation in one of the significant events of the German Revolution of 1848, the Second Democratic Congress, and voter turnout in the 1924 Reichstag election are associated with precinct‐level variations in arrest for treason and high treason. We also explore whether regional communist traditions are likewise associated with later resistance. We find that each additional precinct delegate at the Congress, the presence of a past communist uprising in the precinct, and each percentage point increase in the voter turnout is associated with 0.40, 4.35, and 6.16 additional unconditional expected charges per 100,000 inhabitants respectively.
Unraveling the Effect of Citric Acid on Microstructure, Rheology, and Structural Recovery of Thermoplastic Potato Starch
Authors: Javidi Zeinab , Nazockdast Hossein , Ghasemi Ismail
Published: February 2021

The main objective of the present work is to explore the role of citric acid (CA) on microstructural changes and their impact on the melt rheological behavior, mechanical performance, and shape recovery of thermoplastic starch (TPS). The results of frequency sweep test show a pronounced nonterminal storage modulus (G’) at lower frequencies (high melt elasticity) for TPS, which is found to be greatly reduced in favor of improving the processability through the addition of CA. This could be explained in terms of reduced disentanglements of amylopectin molecules, as a crucial parameter responsible for the 3D‐type interconnected microstructure of TPS, through catalyzing effect of CA on hydrolysis. The results of the temperature sweep test (cooling mode) show a pronounced liquid‐to‐solid transition at ∼136℃ for CA‐modified TPS. This transition could be attributed to the temperature‐driven significant strengthening of the formation of single helical amylose crystalline structure and/or the hydrogen bonds between hydrolyzed amylopectin chains at temperatures below 136℃. The results are found to be consistent with the results obtained from the tensile and DMTA experiments. As expected, the shape recovery of the CA‐modified TPS sample is lower than that of unmodified TPS because of the lower elastic stored energy (stiffness) in the presence of CA, which can be largely compensated by incorporating appropriate nanoparticles.
Entropy based enhanced particle swarm optimization on multi‐objective software reliability modelling for optimal testing resources allocation
Authors: Rani Pooja , Mahapatra G. S.
Published: February 2021

This paper proposes a generalization of the exponential software reliability model to characterize several factors including fault introduction and time‐varying fault detection rate. The software life cycle is designed based on module structure such as testing effort spent during module testing and detected software faults etc. The resource allocation problem is a critical phase in the testing stage of software reliability modelling. It is required to make decisions for optimal resource allocation among the modules to achieve the desired level of reliability. We formulate a multi‐objective software reliability model of testing resources for a new generalized exponential reliability function to characterizes dynamic allocation of total expected cost and testing effort. An enhanced particle swarm optimization (EPSO) is proposed to maximize software reliability and minimize allocation cost. We perform experiments with randomly generated testing‐resource sets and varying the performance using the entropy function. The multi‐objective model is compared with modules according to weighted cost function and testing effort measures in a typical modular testing environment.
Casting position effects on bond performance of reinforcement bars
Authors: Moccia Francesco , Fernández Ruiz Miguel , Metelli Giovanni , Muttoni Aurelio , Plizzari Giovanni
Published: February 2021

The phenomena associated with the consolidation of fresh concrete (bleeding and plastic settlement) are commonly considered significant for the bond performance of reinforcement. However, rules to take care of such influence for design are not consistent amongst design recommendations and may lead to notable differences. With this respect, two failure modes generally govern the bond failure, namely the spalling of the concrete cover (also called splitting failure) and the pull‐out of the reinforcement. In this paper, a detailed investigation is presented on the influence of bleeding and plastic settlement on both failures modes, in an effort to understand their conceptual differences and to clarify how shall consistent design recommendations be formulated. Such investigation is based on a comprehensive experimental programme, comprising 137 pull‐out tests on specimens with different casting conditions, embedment lengths, loading arrangements and concrete covers. On the basis of the test results, the phenomenological differences between pull‐out and spalling failures are clarified, as well as the main influencing phenomena (particularly the potential presence of cracks and voids under the reinforcement and the mechanical properties of concrete). On this basis, a physically‐consistent approach is presented to consider the casting conditions on the bond performance and failure modes.
Seismic behavior of flanged reinforced concrete shear walls with high‐strength stirrup under cyclic loading
Authors: Pinle Zhang , Junxiong Liu , Gan Zhang
Published: February 2021

Twelve half‐scale flanged reinforced concrete (RC) shear wall specimens with high‐strength stirrup were tested to failure under cyclic loading. The effects of axial load ratio, aspect ratio, and web confinement on seismic performances were critically examined. All specimens showed an expected flexural‐dominant behavior, with the crushing of the compressed concrete and the buckling of reinforcement at the boundary elements. The axial load ratio was found to have significant effects to the seismic behavior of the shear walls. Higher loading capacity and lower ductility capacity can be achieved with increases in the axial load ratio. The hysteretic curves of the walls were all unsymmetrical, especially in T‐shaped walls. The specimens showed higher strength and stiffness, but lower ductility capacity when the web was in compression. The use of high‐strength stirrups can effetely confine the compressed concrete and postpone bucking of longitudinal rebars in the free web boundary, thus preventing premature failure when web was in compression. The plastic deformation capacity of all the test specimens was all excellent, and the ultimate drift ratio of all specimens greatly exceeded the allowable inter‐story drift ratio value (1/120) of RC shear wall in accordance with the design provisions of Chinese GB50011‐2010 code.
Performance Studies of Proton Exchange Membrane Fuel Cells with Different Flow Field Designs – Review
Authors: Marappan Muthukumar , Palaniswamy Karthikeyan , Velumani Thiagarajan , Chul Kim Byung , Velayutham Rajavel , Shivakumar Praveenkumar , Sundaram Senthilarasu
Published: February 2021

Proton Exchange Membrane Fuel Cell (PEMFC) is majorly used for power generation without producing any emission. In PEMFC, the water generated in the cathode heavily affects the performance of fuel cell which needs better water management. The flow channel designs, dimensions, shape and size of the rib/channel, effective area of the flow channel and material properties are considered for better water management and performance enhancement of the PEMFC in addition to the inlet reactant's mass flow rate, flow directions, relative humidity, pressure and temperature. With the purpose of increasing the output energy of the fuel cell, many flow field designs are being developed continuously. In this paper, the performance of various conventional, modified, hybrid and new flow field designs of the PEMFC is studied in detail. Further the effects of channel tapering, channel bending, landing to channels width ratios, channel cross‐sections and insertion of baffles/blockages/pin‐fins/inserts are reviewed. The power density of the flow field designs, the physical parameters like active area, dimensions of channel/rib, number of channels; and the operating parameters like temperature and pressure are also tabulated.
LncRNA MEG3 mediates nickel oxide nanoparticles‐induced pulmonary fibrosis via suppressing TGF‐β1 expression and epithelial‐mesenchymal transition process
Authors: Zhan Haibing , Chang Xuhong , Wang Xiaoxia , Yang Mengmeng , Gao Qing , Liu Han , Li Chengyun , Li Sheng , Sun Yingbiao
Published: February 2021

Nickel oxide nanoparticles (NiO NPs) causes pulmonary fibrosis via activating transforming growth factor‐β1 (TGF‐β1) in rats, but its upstream regulatory mechanisms are unknown. This study aimed to explore the role of long noncoding RNA (lncRNA) maternally expressed gene 3 (MEG3) in NiO NPs‐induced collagen deposition. Male Wistar rats were intratracheally instilled with NiO NPs (0.015, 0.06, and 0.24 mg/kg b.w.) twice a week for 9 weeks. Human lung adenocarcinoma epithelial cells (A549 cells) were cultured with NiO NPs (25, 50, and 100 μg/ml) to establish collagen deposition model. We discovered that NiO NPs‐induced rat pulmonary fibrosis was accompanied by the epithelial‐mesenchymal transition (EMT) occurrence and MEG3 down‐regulation in rat lung tissues. In cell collagen deposition model, NiO NPs also evoked EMT and decreased MEG3 expression in a dose‐dependent manner in A549 cells. By overexpressing MEG3 in A549 cells, we found that MEG3 inhibited the level of TGF‐β1, EMT process and collagen formation. Moreover, our data showed that SB431542 (TGF‐β1 inhibitor) had an inhibitory effect on NiO NPs‐induced EMT and collagen formation. Our results indicated that MEG3 inhibited NiO NPs‐induced collagen deposition by regulating TGF‐β1‐mediated EMT process, which may provide some clues for insighting into the mechanisms of NiO NPs‐induced pulmonary fibrosis.
Tolerance and phytoremediation potential of Calopogonium mucunoides to boron
Authors: da Silva Victor Navarro , Frachia Caroline de Lima , Barbosa Isis Caroline Ferreira , da Silva Mariana Bocchi , de Paiva Wesller da Silva , Souza Lucas Anjos , Justino Gilberto Costa , de Camargos Liliane Santos
Published: February 2021

Soil contamination by trace elements (TEs) is a problem of great concern since the industrial revolution. However, not all TEs are essentially toxic, and several micronutrients such as boron (B) play essential roles during plant development and, in this case, B acts in plants as a structural element. Soil B levels above 3.0 mg dm–3 may be toxic to many plants and the greatest input of B to the environment occurs through the anthropic way. An environmentally promising alternative is phytoremediation, in which contaminant‐tolerant plants are used to remove or stabilize TEs in soils. Therefore, this work has been carried out to aim C. mucunoides’ tolerance to increasing B concentrations and its potential as a phytoremediator. We found out that C. mucunoides tolerates B doses up to 480 mg dm−3, the B uptaken is transported at a 1:1 ratio between root and shoot, suggesting that C. mucunoides can be used as a phytostabilizer and phytoextractor due to its potential to be used in phytoremediation techniques because it can tolerate toxic concentrations of B.
A vaccine to prevent initial loss of cognition and eventual Alzheimer's disease in elderly persons
Authors: Fessel Jeffrey
Published: February 2021

Prevention is better than cure and prevention of Alzheimer's disease (AD) may be possible. In elderly persons who are cognitively normal, synaptic hypometabolism as shown by reduced cerebral uptake of fluorodeoxyglucose (18F‐FDG), provides a premonitory signal of potential, future loss of cognition if those individuals also have present evidence of amyloid deposition seen in the Pittsburgh compound B positron emission tomography (PIB‐PET) scan for amyloid. Those are the persons who should be targeted if one aims to prevent AD. The synaptic hypometabolism implies that the brain's availability of adenosine triphosphate (ATP) is inadequate for performance of all required synaptic functions. This review first describes the basis for asserting that reduced cerebral uptake of 18F‐FDG accurately reflects synaptic hypometabolism; second, explains the basis for asserting that hypometabolism implies inadequate ATP; third, shows that amyloid beta (Aβ) itself, Aβ modified by pyroglutamate to become a molecule termed pE(3)Aβ, and cyclophilin‐D, in concert are the main contributors to inadequate synaptic ATP and that, therefore, reducing all of their levels would neutralize their combined effect and correct the hypometabolism. pE(3)Aβ is more neurotoxic than unmodified Aβ; and cyclophilin D inhibits ATP synthase and reduces ATP formation. Finally, this review describes an mRNA self‐replicating vaccine that will raise brain levels of ATP by reducing Aβ, pyroglutamate‐modified Aβ, and cyclophilin‐D, and thereby—in cognitively normal elderly persons who have synaptic hypometabolism—prevent initiation of the process that terminates in AD.
An overview of the hydrology of non‐perennial rivers and streams
Authors: Shanafield Margaret , Bourke Sarah A , Zimmer Margaret A , Costigan Katie H
Published: February 2021

Non‐perennial rivers and streams are ubiquitous on our planet. Although several metrics have been used to statistically group or compare streamflow characteristics, there is currently no widely used definition of how many days or over what reach length surface flow must cease in order to classify a river as non‐perennial. At the same time, the breadth of climate and geographic settings for non‐perennial rivers leads to diversity in their flow regimes, such as how often or how quickly they go dry. These rivers have a rich and expanding body of literature addressing their ecologic and geomorphic features, but are often said to be ignored by hydrologists. Yet there is much we do know about their hydrology in terms of streamflow generation processes, water losses, and variability in flow. We also know that while they are prevalent in arid regions, they occur across all climate types and experience a diverse set of natural and anthropogenic controls on streamflow. Furthermore, measuring and modeling the hydrology of these rivers presents a distinct set of challenges, and there are many research directions, which still require further attention. Therefore, we present an overview of the current understanding, methodologic challenges, knowledge gaps, and research directions for hydrologic understanding of non‐perennial rivers; critical topics in light of both growing global water scarcity and ever‐changing laws and policies that dictate whether and how much environmental protection these rivers receive.

This article is categorized under:

Science of Water > Science of Water
Cover Image, Volume 13, Issue 2
Authors: Shojaie Ali
Published: February 2021

The cover image is based on the Advance Review Differential network analysis: A statistical perspective by Ali Shojaie., https://doi.org/10.1002/wics.1508.

image
Integrative clustering methods for multi‐omics data
Authors: Zhang Xiaoyu , Zhou Zhenwei , Xu Hanfei , Liu Ching‐Ti
Published: February 2021

Integrative analysis of multi‐omics data has drawn much attention from the scientific community due to the technological advancements which have generated various omics data. Leveraging these multi‐omics data potentially provides a more comprehensive view of the disease mechanism or biological processes. Integrative multi‐omics clustering is an unsupervised integrative method specifically used to find coherent groups of samples or features by utilizing information across multi‐omics data. It aims to better stratify diseases and to suggest biological mechanisms and potential targeted therapies for the diseases. However, applying integrative multi‐omics clustering is both statistically and computationally challenging due to various reasons such as high dimensionality and heterogeneity. In this review, we summarized integrative multi‐omics clustering methods into three general categories: concatenated clustering, clustering of clusters, and interactive clustering based on when and how the multi‐omics data are processed for clustering. We further classified the methods into different approaches under each category based on the main statistical strategy used during clustering. In addition, we have provided recommended practices tailored to four real‐life scenarios to help researchers to strategize their selection in integrative multi‐omics clustering methods for their future studies.

This article is categorized under:

Statistical Learning and Exploratory Methods of the Data Sciences > Clustering and Classification

Applications of Computational Statistics > Genomics/Proteomics/Genetics

Statistical and Graphical Methods of Data Analysis > Analysis of High Dimensional Data
Analysis of a hollow fiber in thermoelectric materials considering interfacial thermal resistance
Authors: Xing Shi‐Chao , Yu Chuanbin , Gao Cun‐Fa
Published: February 2021

Hollow fibers are commonly introduced into flexible thermoelectric materials for certain engineering applications. However, significant stress concentration may be caused in the vicinity of the interface between the fibers and thermoelectric matrix threatening the reliability of the composite structure. In this paper, we study the plane deformation problem of a rigid hollow fiber embedded in a thermoelectric material. By utilizing the complex variable method, the closed‐form solutions for electric, thermal and elastic fields in both of the fiber and the matrix are obtained. The effects of the thermal resistance and geometric parameters of the hollow fiber on the temperature and stress distributions are numerically examined. The results show that the temperature difference (amplitude of variation in temperature in the matrix side around the interface) and the stress field around the interface are proportion to the inner radius of the hollow fiber and the thermal resistance, respectively. Meanwhile, we find that the temperature and the stress distributions are more sensitive to the geometric parameters than to the thermal resistance. The results in this paper may serve as guidelines for design of fibers‐filled thermoelectric structures.
Obstacles to constructing de Sitter space in string theory
Authors: Dine Michael , Law-Smith Jamie A. P. , Sun Shijun , Wood Duncan , Yu Yan
Published: February 2021

Abstract

There have been many attempts to construct de Sitter space-times in string theory. While arguably there have been some successes, this has proven challenging, leading to the de Sitter swampland conjecture: quantum theories of gravity do not admit stable or metastable de Sitter space. Here we explain that, within controlled approximations, one lacks the tools to construct de Sitter space in string theory. Such approximations would require the existence of a set of (arbitrarily) small parameters, subject to severe constraints. But beyond this one also needs an understanding of big-bang and big-crunch singularities that is not currently accessible to standard approximations in string theory. The existence or non-existence of metastable de Sitter space in string theory remains a matter of conjecture.
Phase transitions from the fifth dimension
Authors: Agashe Kaustubh , Du Peizhi , Ekhterachian Majid , Kumar Soubhik , Sundrum Raman
Published: February 2021

Abstract

We study the cosmological transition of 5D warped compactifications, from the high-temperature black-brane phase to the low-temperature Randall-Sundrum I phase. The transition proceeds via percolation of bubbles of IR-brane nucleating from the black-brane horizon. The violent bubble dynamics can be a powerful source of observable stochastic gravitational waves. While bubble nucleation is non-perturbative in 5D gravity, it is amenable to semiclassical treatment in terms of a “bounce” configuration interpolating between the two phases. We demonstrate how such a bounce configuration can be smooth enough to maintain 5D effective field theory control, and how a simple ansatz for it places a rigorous lower-bound on the transition rate in the thin-wall regime, and gives plausible estimates more generally. When applied to the Hierarchy Problem, the minimal Goldberger-Wise stabilization of the warped throat leads to a slow transition with significant supercooling. We demonstrate that a simple generalization of the Goldberger-Wise potential modifies the IR-brane dynamics so that the transition completes more promptly. Supercooling determines the dilution of any (dark) matter abundances generated before the transition, potentially at odds with data, while the prompter transition resolves such tensions. We discuss the impact of the different possibilities on the strength of the gravitational wave signals. Via AdS/CFT duality the warped transition gives a theoretically tractable holographic description of the 4D Composite Higgs (de)confinement transition. Our generalization of the Goldberger-Wise mechanism is dual to, and concretely models, our earlier proposal in which the composite dynamics is governed by separate UV and IR RG fixed points. The smooth 5D bounce configuration we introduce complements the 4D dilaton/radion dominance derivation presented in our earlier work.
From correlation functions to event shapes in QCD
Authors: Chicherin D. , Henn J. M. , Sokatchev E. , Yan K.
Published: February 2021

Abstract

We present a method for calculating event shapes in QCD based on correlation functions of conserved currents. The method has been previously applied to the maximally supersymmetric Yang-Mills theory, but we demonstrate that supersymmetry is not essential. As a proof of concept, we consider the simplest example of a charge-charge correlation at one loop (leading order). We compute the correlation function of four electromagnetic currents and explain in detail the steps needed to extract the event shape from it. The result is compared to the standard amplitude calculation. The explicit four-point correlation function may also be of interest for the CFT community.
S-fold magnetic quivers
Authors: Bourget Antoine , Giacomelli Simone , Grimminger Julius F. , Hanany Amihay , Sperling Marcus , Zhong Zhenghao
Published: February 2021

Abstract

Magnetic quivers and Hasse diagrams for Higgs branches of rank r 4d $$ \mathcal{N} $$
N
= 2 SCFTs arising from ℤℓ$$ \mathcal{S} $$
S
-fold constructions are discussed. The magnetic quivers are derived using three different methods: 1) Using clues like dimension, global symmetry, and the folding parameter ℓ to guess the magnetic quiver. 2) From 6d $$ \mathcal{N} $$
N
= (1, 0) SCFTs as UV completions of 5d marginal theories, and specific FI deformations on their magnetic quiver, which is further folded by ℤℓ. 3) From T-duality of Type IIA brane systems of 6d $$ \mathcal{N} $$
N
= (1, 0) SCFTs and explicit mass deformation of the resulting brane web followed by ℤℓ folding. A choice of the ungauging scheme, either on a long node or on a short node, yields two different moduli spaces related by an orbifold action, thus suggesting a larger set of SCFTs in four dimensions than previously expected.
Analytic study on chiral phase transition in holographic QCD
Authors: Li Meng-Wei , Yang Yi , Yuan Pei-Hung
Published: February 2021

Abstract

The chiral symmetry breaking (χsb) is one of the most fundamental problems in QCD. In this paper, we calculate quark condensation analytically in a holographic QCD model dual to the Einstein-Maxwell-Dilaton (EMD) system coupled to a probe scalar field. We find that the black hole phase transition in the EMD system seriously affects χsb. At small chemical potential, χsb behaves as a crossover. For large chemical potential μ > μc, χsb becomes first order with exactly the same transition temperature as the black hole phase transition by a bypass mechanism. The phase diagram we obtained is qualitatively consistent with the recent results from lattice QCD simulations and NJL models.
Challenging Infrastructure Project Assisted by Monitoring and Numerical Modelling as the Follo Line Tunnels were Excavated Below Existing Tunnels
Authors: Trinh Nghia Quoc , Holmøy Kristin Hilde , Wiig Hanne Elisabeth
Published: February 2021

Just south of Oslo Central Station, the new high-speed Follo Line railway tunnels pass beneath the existing Ekeberg road tunnels. This paper presents the construction methods, numerical model, and monitoring program used to assess the stability of the E6 road tunnels during the excavation of the Follo Line tunnels only a few metres below. The construction of the Follo Line was approved subject to three conditions: (1) there should be no negative effect on the stability of the Ekeberg tunnels, (2) the traffic flow in the Ekeberg tunnels had to be maintained at all times and (3) any risk of instability in the existing tunnels must be detected beforehand, so that necessary precautionary actions could be taken in good time. To deal with the challenges, SINTEF developed a comprehensive analysis procedure, combining continuous rock stress measurements and displacement measurements with 2D and 3D numerical modelling. The rock stress change monitoring was used together with the numerical model to monitor the stability conditions in the Ekeberg tunnels as the Follo Line tunnels were excavated. This ensured that any risk of instability in the existing tunnels could be detected in advance to enable precautionary action to be taken. The successful completion of the new tunnels without any disturbance to the road tunnels shows that the procedure would be useful for dealing with similar applications in the future.
Tropical Duality in $$(d+2)$$-Angulated Categories
Authors: Reid Joseph
Published: February 2021

Let $$\mathscr {C}$$
C
be a 2-Calabi–Yau triangulated category with two cluster tilting subcategories $$\mathscr {T}$$
T
and $$\mathscr {U}$$
U
. A result from Jørgensen and Yakimov (Sel Math (NS) 26:71–90, 2020) and Demonet et al. (Int Math Res Not 2019:852–892, 2017) known as tropical duality says that the index with respect to $$\mathscr {T}$$
T
provides an isomorphism between the split Grothendieck groups of $$\mathscr {U}$$
U
and $$\mathscr {T}$$
T
. We also have the notion of c-vectors, which using tropical duality have been proven to have sign coherence, and to be recoverable as dimension vectors of modules in a module category. The notion of triangulated categories extends to the notion of $$(d+2)$$

(
d
+
2
)

-angulated categories. Using a higher analogue of cluster tilting objects, this paper generalises tropical duality to higher dimensions. This implies that these basic cluster tilting objects have the same number of indecomposable summands. It also proves that under conditions of mutability, c-vectors in the $$(d+2)$$

(
d
+
2
)

-angulated case have sign coherence, and shows formulae for their computation. Finally, it proves that under the condition of mutability, the c-vectors are recoverable as dimension vectors of modules in a module category.
Optimising Exposure for Children and Adolescents with Anxiety, OCD and PTSD: A Systematic Review
Authors: Plaisted Hannah , Waite Polly , Gordon Kate , Creswell Cathy
Published: February 2021

Cognitive behavioural therapy is an effective treatment for anxiety disorders in children and young people; however, many do not benefit. Behavioural exposure appears to be the critical ingredient in the treatment of anxiety disorders. Research with adults has identified innovative strategies to optimise exposure-based treatments, yet it is not clear how to optimise the effects of exposure for children and young people. This review was a preliminary exploration of the association between potential optimisation strategies and treatment procedures and outcomes for the treatment of child anxiety symptoms/disorders. We searched Psych-Info and Medline databases using a systematic search strategy and identified 29 articles. We found preliminary evidence that some specific strategies may enhance the effects of exposure, such as dropping safety behaviours, parents and therapists discouraging avoidance, and the use of homework. However, not one significant finding was replicated by another study for the same timepoint using the same methodology. To a large degree, this lack of replication reflects a limited number of studies combined with a lack of consistency across studies around conceptualisations, methodological approaches, and outcome measures making it difficult to make meaningful comparisons between studies and draw firm conclusions. Examination is needed of a wide range of theoretically-driven potential optimisation strategies using methodologically robust, preclinical studies with children and young people. Furthermore, the methods used in future research must enable comparisons across studies and explore developmental differences in the effects of particular optimisation strategies.
Setting the priority medicinal plants for conservation in Indonesia
Authors: Cahyaningsih Ria , Magos Brehm Joana , Maxted Nigel
Published: February 2021

Setting priority species for conservation planning in a large and biodiverse country such as Indonesia is crucial. At least 80% of the medicinal plant species in South East Asia can be found in Indonesia, whether they are native or introduced. However, their conservation is currently ineffective due to limited human and financial resources. By examining factors such as species' occurrence status, rarity and part of the plant harvested, the various Indonesian medicinal plant species can be prioritised for conservation planning. In this study, various threatened plant species have been included in the priority list as well as those listed in related legislation. Some 233 species within 161 genera and 71 families are recommended for prioritisation. An inventory of these priority species was produced presenting compiled data including vernacular names, plant habit, harvested plant part, uses, distribution, whether it is conserved ex situ, and their DNA barcoding. Significantly 41.20% of priority species have no information on their current conservation status in either in situ or ex situ national or international genebanks.
Implicit Semantic Processing of Linguistic and Non-linguistic Stimuli in Adults with Autism Spectrum Disorder
Authors: O’Rourke Emme , Coderre Emily L.
Published: February 2021

While many individuals with autism spectrum disorder (ASD) experience difficulties with language processing, non-linguistic semantic processing may be intact. We examined neural responses to an implicit semantic priming task by comparing N400 responses—an event-related potential related to semantic processing—in response to semantically related or unrelated pairs of words or pictures. Adults with ASD showed larger N400 responses than typically developing adults for pictures, but no group differences occurred for words. However, we also observed complex modulations of N400 amplitude by age and by level of autistic traits. These results offer important implications for how groups are delineated and compared in autism research.