Unique Characterization Research Articles

An in-depth study of nonlinear parametric characterization for thermoelectric generator modules

Thermoelectric (TE) parameters provide indispensable data for the optimal design, accurate modeling, and performance assessment of off-the-shelf TE modules. However, the lack of unified characterization methods for these nonlinear data creates challenges for the design of large-scale TE systems. This paper aims at a thorough exploration of the accuracy, efficiency, and applicability of five typically reported characterization methods in terms of temperature-dependent material-level TE parameters (Seebeck coefficient, thermal conductivity and electrical resistivity). A common test setup was built and specifically improved for the convenient and high-precision measurement of heat rate. The four methods except for the Buist’s modified Harman method can characterize the satisfactory material-level TE parameters only if the thermoelectric generator (TEG)’s irreversible factors are considered including the thermal resistances of substrates and interlaminar contact resistances. The applicability of each method in a large temperature range is discussed by simulation beyond their inherent limits of adopted setups in this paper. Most methods show significant deviations at high temperatures due to their inherent parametric spatial-independence assumptions. From the perspective of their theoretical feasibility and practical accuracy, the quasi steady-state method is more advantageous than others. This research can guide the employment of characterization methods and assist the design and optimization of large-scale TE systems.

A unifying characterization of tree-based networks and orchard networks using cherry covers

Phylogenetic networks are used to represent evolutionary relationships between species in biology. Such networks are often categorized into classes by their topological features, which stem from both biological and computational motivations. We study two network classes in this paper: tree-based networks and orchard networks. Tree-based networks are those that can be obtained by inserting edges between the edges of an underlying tree. Orchard networks are a recently introduced generalization of the class of tree-child networks. Structural characterizations have already been discovered for tree-based networks; this is not the case for orchard networks. In this paper, we introduce cherry covers—a unifying characterization of both network classes—in which we decompose the edges of the networks into so-called cherry shapes and reticulated cherry shapes. We show that cherry covers can be used to characterize the class of tree-based networks as well as the class of orchard networks. Moreover, we also generalize these results to non-binary networks.

Stress path investigation of fatigue characteristics of cement stabilized macadam

Fatigue strength is the core of pavement structure design. For semi-rigid base asphalt pavement, the anti-fatigue design of cement stabilized macadam is the key to the entire pavement design process. However, the structural layer of cement stabilized macadam is in a complex stress path, and the traditional S-N fatigue equation is various in different stress paths. Single S-N fatigue equation cannot truly reflect the actual pavement’s stress path (three-dimensional structure), thus bringing challenges to make selections in engineering design. This study aims to accurately perform the cement stabilized macadam’s fatigue characteristics in structural design. First, the specimens were prepared under vibration mixing and vibration molding, and the uniaxial compression, bending, and indirect tensile mechanical properties were studied. Then, based on test results and Miller yield criterion, the strength yield surfaces of cement stabilized macadam were established with an increase in loading rates. Finally, the generalized shear stress strength ratio is proposed to unify fatigue performance under different test methods. The results show that the strength rises with an increase in loading rates, and the yield surface is a parabola. Miller yield surface referrings as fatigue damage surface comprehensively describes the failure characteristics of cement stabilized macadam. The new fatigue equation curves based on the Miller yield surface are significantly closed in different stress paths and pass-through points (1, 1). Using one equation can represent the fatigue feature of cement stabilized macadam thoroughly. It realizes the unified characterization of fatigue performances and eliminates the effect of test methods and conditions on fatigue results. This study solves the long-standing problem: the fatigue equations obtained by different test methods are various, which improves the design accuracy of the semi-rigid base pavement.

592 Characterization of lichen planopilaris in men: A retrospective analysis

Lichen planopilaris (LPP) and subtype frontal fibrosing alopecia (FFA) are primary lymphocytic cicatricial alopecias distinguished by morphology and distribution. LPP affects Caucasian women from 25 to 70 years with a female to male ratio of 1.8:1. LPP is thought to have an autoimmune component and has significant association with thyroid disease. Due to low male prevalence, a paucity of literature demonstrates the characterization of LPP/FFA in men. This study evaluates the clinical characteristics of a male cohort with LPP and/or FFA at a single tertiary hair center. A retrospective review of male patients diagnosed with LPP and/or FFA at Massachusetts General Hospital Hair Loss Clinic from 2017 to 2020 was performed. We identified 24 men diagnosed with LPP, FFA, or LPP/FFA overlap. The mean age at presentation was 45.5 years (range 15-74 years). 70.8% were Caucasian, 12.5% Asian, 8.3% Black, 8.3% unknown/unreported. Eyebrows (20.8%), arms/legs (16.7%), and beard (16.7%) were the most commonly reported areas of non-scalp involvement. 62.5% reported one or more scalp symptoms or signs including pruritus, burning, tenderness/pain, flaking or redness. 50% reported 1 or more first degree relatives with hair loss and of those, 8.3% had similar hair loss type. Two patients reported a family history of 1 or more autoimmune conditions with 1 report of thyroid disease. No patients reported a personal history of thyroid disease. Most commonly reported treatments tried for hair loss prior to diagnosis included topical minoxidil (25%) and topical clobetasol (16.7%). 20.8% of patients reported regular use of SPF year-round and 12.5% regularly colored their hair. Our study demonstrates the unique characterization of LPP/FFA in men. Most men reported scalp symptoms and 16.7% had beard involvement. Most men reported no history of thyroid disease. Further studies are warranted to characterize the LPP/FFA male population.

Lipidomics-Based Comparison of Molecular Compositions of Green, Yellow, and Red Bell Peppers.

Identifying and annotating the molecular composition of individual foods will improve scientific understanding of how foods impact human health and how much variation exists in the molecular composition of foods of the same species. The complexity of this task includes distinct varieties and variations in natural occurring pigments of foods. Lipidomics, a sub-field of metabolomics, has emerged as an effective tool to help decipher the molecular composition of foods. For this proof-of-principle research, we determined the lipidomic profiles of green, yellow and red bell peppers (Capsicum annuum) using liquid chromatography mass spectrometry and a novel tool for automated annotation of compounds following database searches. Among 23 samples analyzed from 6 peppers (2 green, 1 yellow, and 3 red), over 8000 lipid compounds were detected with 315 compounds (106 annotated) found in all three colors. Assessments of relationships between these compounds and pepper color, using linear mixed effects regression and false discovery rate (<0.05) statistical adjustment, revealed 11 compounds differing by color. The compound most strongly associated with color was the carotenoid, β-cryptoxanthin (p-value = 7.4 × 10−5; FDR adjusted p-value = 0.0080). These results support lipidomics as a viable analytical technique to identify molecular compounds that can be used for unique characterization of foods.

A synoptic view of the natural time distribution and contemporary earthquake hazards in Sumatra, Indonesia

Tectonic plate interactions in Sumatra have caused a range of devastating earthquake events. In this study, we develop an analytical framework, known as earthquake nowcasting (Rundle et al. in Earth and Space Science 3:480–486, 2016. 10.1002/2016EA000185), to assess the current dynamical state of earthquake hazards in Sumatra and adjacent islands from the empirical distribution of natural times, the cumulative counts of “small” events (say, M ≥ 4) between two successive “large” earthquakes (say, M ≥ 6.5). Based on 50 years of instrumental earthquake data, the best fit Weibull distribution assigns earthquake potential score between 29 and 96% to 19 large cities in the study region with the values (%) of Aceh (72), Bengkulu (34), Binjai (81), Jambi (35), Lahat (29), Lampung (45), Lhoksuemawe (54), Medan (75), Mentawai (76), Meulaboh (71), Nias (95), Palembang (80), Padang (74), Pekanbaru (39), Sabang (72), Siantar (82), Sibolga (92), Sinabang (96), and Tanjung Balai (55). These areal-source based nowcast scores, analogous to the tectonic stress buildup since the last major event, essentially provides a unique characterization of the current level of seismic progression of a city through its repetitive cycle of regional earthquakes. Inclusion of dependent events with aftershocks being more common and the concept of natural times are some of the distinctive advantages of the proposed method. The resulting natural time statistics and consequent earthquake potential scores will facilitate seismic risk estimation, multistate decision-making, and community awareness, leading to an efficient seismic risk reduction strategy in the densely populated study region.

Pre-clinical left ventricular myocardial remodeling in patients with Friedreich's ataxia: A cardiac MRI study.

BackgroundHeart Failure (HF) is the most common cause of death in Friedreich’s ataxia (FRDA), an inherited mitochondrial disease. Myocardial fibrosis and myocardial hypertrophy are well-documented autopsy features among FRDA patients with HF.ObjectivesTo leverage the unique tissue characterization features of cardiac magnetic resonance (CMR) for characterizing myocardial remodeling in patients with genetically confirmed FRDA without HF and preserved left ventricular ejection fraction (LVEF > 55%).MethodsTwenty-seven FRDA’s patients (age 27.6 ± 9.7 years, 15 women) and 10 healthy controls (32.6±7.3 years, 5 women) underwent a CMR for assessment of LV function, myocardial T1, late gadolinium enhancement (LGE), extracellular volume fraction (ECV), and intracellular water-lifetime (τic), a marker of cardiomyocyte size.ResultsAs compared to controls, FRDA patients had a preserved LVEF (LVEF: 70.5±7.4% vs. 63.9±9.0%, P<0.058), larger LV mass index (LVMASSi: 61±21.7 vs. 45±4.2g/m2, P<0.02), and decreased LV end-diastolic volume index (LVEDVi 53.1±12.0 vs. 75.7±16.1ml/m2, P<0.001), compared with controls. Additionally, ECV and cardiomyocyte size (τic,) were larger in FRDA patients (ECV: 0.36 ±0.05 vs. 0.25±0.02, P<0.001; τic: 0.15±0.08 vs. 0.06±0.03 s, P = 0.02). ECV and τic were positively associated with LV mass-to-volume ratio (ECV: r = 0.57, P = 0.003; τic: r = 0.39; P = 0.05). LVMASSi and cardiomyocyte mass-index [(1−ECV)·LVMASSi] declined with age at the CMR exam, independent of the age at initial diagnosis.ConclusionsLV hypertrophy and concentric LV remodeling in FRDA are associated at the tissue level with an expansion of the ECV and an increase in cardiomyocyte size. The adverse tissue remodeling assessed by ECV and τic is associated with more severe cardiomyopathy classification, suggesting a role for these markers in tracking disease progression.

P37.22 Unique Characterization of KRAS Mutation in Non-Small Cell Lung Cancer in Thai Population

P37.22 Unique Characterization of KRAS Mutation in Non-Small Cell Lung Cancer in Thai Population

A novel unified characterization parameter of in‐plane and out‐of‐plane constraints based on critical CTOA

AbstractThere is much controversy in using laboratory specimens to predict the fracture behavior of large industrial constructions because of their different constraints. Although several parameters have been proposed to characterize the constraint effect, there are still some limitations. To address this issue, a novel unified characterization parameter of constraint based on the critical crack tip opening angle (CTOAC) is defined. Firstly, the calibrated finite element technologies for simulation of static and dynamic crack are used to determine the equivalent plastic strain (εp) distribution around the crack tip and the evolution history of CTOA for specimens with different in‐plane and out‐of‐plane constraints, respectively. Secondly, the feasibility of the equivalent plastic strain at the crack tip when CTOA reaches its critical value to unified measure both in‐plane and out‐of‐plane constraints is investigated. The results indicate that the area APEEQ surrounded by the isoline of equivalent plastic strain εp can describe both in‐plane and out‐of‐plane constraints and the interaction between them. Finally, a novel constraint characterization parameter η is defined. It is found that there is a linear relationship, which depends only on the material and regardless of the selection of the εp isoline, between the normalized fracture toughness CTOAC/CTOAref and η1/2. The work in this paper is expected to realize the matching of constraints between different laboratory specimens or industrial constructions.

A pilot study on biaxial mechanical, collagen microstructural, and morphological characterizations of a resected human intracranial aneurysm tissue

Intracranial aneurysms (ICAs) are focal dilatations that imply a weakening of the brain artery. Incidental rupture of an ICA is increasingly responsible for significant mortality and morbidity in the American’s aging population. Previous studies have quantified the pressure-volume characteristics, uniaxial mechanical properties, and morphological features of human aneurysms. In this pilot study, for the first time, we comprehensively quantified the mechanical, collagen fiber microstructural, and morphological properties of one resected human posterior inferior cerebellar artery aneurysm. The tissue from the dome of a right posterior inferior cerebral aneurysm was first mechanically characterized using biaxial tension and stress relaxation tests. Then, the load-dependent collagen fiber architecture of the aneurysm tissue was quantified using an in-house polarized spatial frequency domain imaging system. Finally, optical coherence tomography and histological procedures were used to quantify the tissue’s microstructural morphology. Mechanically, the tissue was shown to exhibit hysteresis, a nonlinear stress-strain response, and material anisotropy. Moreover, the unloaded collagen fiber architecture of the tissue was predominantly aligned with the testing Y-direction and rotated towards the X-direction under increasing equibiaxial loading. Furthermore, our histological analysis showed a considerable damage to the morphological integrity of the tissue, including lack of elastin, intimal thickening, and calcium deposition. This new unified characterization framework can be extended to better understand the mechanics-microstructure interrelationship of aneurysm tissues at different time points of the formation or growth. Such specimen-specific information is anticipated to provide valuable insight that may improve our current understanding of aneurysm growth and rupture potential.

PathExNET: A tool for extracting pathway expression networks from gene expression statistics

A fundamental issue related to the understanding of the molecular mechanisms, is the way in which common pathways act across different biological experiments related to complex diseases. Using network-based approaches, this work aims to provide a numeric characterization of pathways across different biological experiments, in the prospect to create unique footprints that may characterise a specific disease under study at a pathway network level. In this line we propose PathExNET, a web service that allows the creation of pathway-to-pathway expression networks that hold the over- and under expression information obtained from differential gene expression analyses. The unique numeric characterization of pathway expression status related to a specific biological experiment (or disease), as well as the creation of diverse combination of pathway networks generated by PathExNET, is expected to provide a concrete contribution towards the individualization of disease, and further lead to a more precise personalised medicine and management of treatment.PathExNET is available at: https://bioinformatics.cing.ac.cy/PathExNET and at https://pathexnet.cing-big.hpcf.cyi.ac.cy/

Frequency-domain characterization of varying random vibration loading by a non-stationarity matrix

Spectral analysis constitutes an essential technique for random vibration fatigue. The power spectral density (PSD) provides an efficient, statistically unique characterization of stationary Gaussian loading which can be effectively processed via linear systems theory and load-spectrum estimators such as the Dirlik formulation. The PSD represents vibration loading by its averaged intensity for frequency. However, if the intensity varies throughout a dataset, i.e. the loading is non-stationary, the PSD has a fundamental flaw – it conceals any information about its evolution. Consequently, the PSD is not qualified to describe non-stationary loading and thus cannot represent instantaneous highly damaging events in a fatigue assessment. Therefore, this article proposes a statistical characterization particularly formulated for the specifications of non-stationary random vibration fatigue. We introduce a non-stationarity matrix defined as the auto-correlation matrix of short-time Fourier transforms, which describes the average variation and interaction of intensity by frequency. This characterization can directly be related to fourth-order statistics (kurtosis, trispectrum, etc.) and allows to be processed via linear systems theory. Thereby the influence of a loading’s non-stationarity structure on structural responses, and thus fatigue damage, can be assessed. Furthermore, this article provides the basis for an accompanying article in which the non-stationarity matrix finds application to efficiently perform fatigue analyses for non-stationary loading via a statistical approach using load-spectrum estimators.

Global Safety Database Summary of COVID-19-Related Drug Utilization-Safety Surveillance: A Sponsor's Perspective.

IntroductionEvidence-based clinical data on coronavirus disease 2019 (COVID-19) pharmacotherapies are scarce.ObjectiveThis study documented and characterized COVID-19 cases reported in individuals receiving treatment with Pfizer pharmaceutical products and cases that reported use of Pfizer pharmaceutical products for COVID-19 treatment.MethodsThis retrospective observational review leveraged the Pfizer safety database containing adverse event data collected in association with use of Pfizer products between 1 October, 2019, and 25 June, 2020; the database includes worldwide adverse event data from various sources. Selected Medical Dictionary for Drug Regulatory Activities (MedDRA®) Preferred Terms and subsequent clinical review were used to characterize COVID-19 cases.ResultsOver 1500 relevant cases were identified over an 8-month period. In cases that reported COVID-19, immunosuppressant/immunomodulating agents, followed by anticoagulant/antithrombic agents and corticosteroids, were the most frequently reported agents. The frequent reporting of immunosuppressant/immunomodulating agents among cases of COVID-19 suggests increased vulnerability to infection among treated patients, either because of immunosuppressive effects of certain agents or the nature of the underlying treated condition. In cases involving off-label pharmacotherapy use for the treatment of COVID-19-related conditions, the most frequently reported therapeutic classes included antibiotics, antimalarial agents, antivirals/antiretroviral agents, immunosuppressant/immunomodulating agents, corticosteroids, anticoagulants, and immunoglobulin/interferons. The most frequently reported pharmacotherapeutic agents were azithromycin and chloroquine/hydroxychloroquine, followed by lopinavir-ritonavir, ceftriaxone, and tofacitinib. The most frequently reported clinical adverse events associated with azithromycin (as sole therapy or combined with chloroquine/hydroxychloroquine) include electrocardiogram QT prolonged, drug interaction, hepatitis, diarrhea, and hepatitis acute. Regarding cardiac-related events, 19% (120/645) of azithromycin cases reported events associated with QT prolongation/torsade de pointes (which included seven fatal cardiac events). The most frequently reported clinical adverse events associated with other commonly used agents are also presented.ConclusionsThis pharmacovigilance surveillance study provides a unique characterization of cases in which a broad range of pharmaceutical products was reported in relation to COVID-19.

Layered Electrode Architectures Enabled By Holey Graphene Hosts

Battery electrodes are typically prepared using a slurry-based method, where high boiling point organic solvents are typically used with a polymer binder to disperse active electrode materials and conductive carbon additives followed by casting onto current collector sheets. In this process, the use of organic solvents are environmentally hazardous, energy intensive, and time-consuming, while polymeric binders add weight and can undergo parasitic reactions during battery cycling. Here we discuss the use of a unique conductive carbon nanomaterial, namely holey graphene, as a multifunctional host that can be processed via a facile, solvent-free, binder-free, cold pressing method to prepare electrodes with unique architectures. This approach can accommodate a broad range of battery chemistries, such as lithium oxygen/carbon dioxide (Li-O2/CO2), lithium sulfur/selenium (Li-S/Se), and various lithium ion chemistries. The successful use of dry, cold compression allows the convenient modification of electrode mass loading with unique architectures containing active materials randomly mixed or layered with single or multiple layers of one or more active materials. In the conventional slurry-based electrode fabrication method, it is difficult, if not impossible, to achieve such layered architectures. In particular, the layered electrode architectures from the dry, cold press approach are easy to fabricate without significantly sacrificing device performance, and are amenable to continuous roll-to-roll dry processing. In addition, these architectures offer unprecedented perspectives on the battery material loading vs. utilization efficiency, as well as enabling unique characterization opportunities to advance mechanistic understanding of various battery chemistries. Potential applications of this unique electrode fabrication approach for solid-state batteries will also be discussed.

Single Cortical Neurons as Deep Artificial Neural Networks

Utilizing recent advances in machine learning, we introduce a systematic approach to characterize the complexity of the input/output (I/O) mapping of neurons. Deep neural networks (DNNs) were trained to replicate the I/O characteristics of nonlinear model of layer 5 cortical pyramidal cell (L5PC) at the millisecond (spiking) resolution. When bombarded by AMPA-mediated synapses, a Fully-Connected-NN with one hidden layer captured the I/O mapping of the L5PC. However, with NMDA-based synapses, a Temporally-Convolutional-DNN with seven layers was required. This DNN generalized well to inputs well-outside of inputs it received during training, including spatio-temporal structured inputs over restricted parts of the dendritic tree. The weight matrices of this DNN provide new insights into the transformation between dendritic inputs to axonal outputs. This study provides a unified characterization of the computational complexity (“depth”) of neurons and suggests that the cortical networks they compose have a non-classical architecture, potentially more powerful than previously assumed.

A unified characterization of the randomized strategy-proof rules

We show that a large class of restricted domains such as single-peaked, single-crossing, single-dipped, tree-single-peaked with top-set along a path, Euclidean, multi-peaked, intermediate (Grandmont (1978)), etc., can be characterized by using betweenness property, and we present a unified characterization of unanimous and strategy-proof random rules on these domains. As corollaries of our result, we show that all the domains we consider in this paper satisfy tops-onlyness and deterministic extreme point property. Finally, we consider weak preferences and provide a class of unanimous and strategy-proof random rules on those domains.

SL(n) covariant function-valued valuations

Classifications of SL(n) covariant function-valued valuations are established with some assumptions of continuity. New valuations, for example, weighted moment functions, are introduced and our classifications give unified characterizations of the Laplace transform on convex bodies, Lp moment bodies, Lp difference bodies, and polar Lp moment bodies (L−p intersection bodies). Using the new classifications, we also establish some Euler-type relations.

Unified Theory to Characterize Floquet Topological Phases by Quench Dynamics

The conventional characterization of periodically driven systems usually necessitates the time-domain information beyond Floquet bands, hence lacking universal and direct schemes of measuring Floquet topological invariants. Here we propose a unified theory, based on quantum quenches, to characterize generic d-dimensional Floquet topological phases in which the topological invariants are constructed with only minimal information of the static Floquet bands. For a d-dimensional phase that is initially static and trivial, we introduce the quench dynamics by suddenly turning on the periodic driving. We show that the quench dynamics exhibits emergent topological patterns in (d-1)-dimensional momentum subspaces where Floquet bands cross, from which the Floquet topological invariants are directly obtained. This result provides a simple and unified characterization in which one can extract the number of conventional and anomalous Floquet boundary modes and identify the topologically protected singularities in the phase bands. These applications are illustrated with one- and two-dimensional models that are readily accessible in cold-atom experiments. Our study opens a new framework for the characterization of Floquet topological phases.

A Note on Intended and Standard Models

Abstract This note discusses some problems concerning intended, standard, and nonstandard models of mathematical theories. We pay attention to the role of extremal axioms in attempts at a unique characterization of the intended models. We recall also Jan Woleński’s views on these issues.

Multi-scale characterization of unconventional tight carbonate reservoir: Insights from October oil filed, Gulf of Suez rift basin, Egypt

The thick Eocene carbonate deposits that are newly ascribed as Radwany Formation (previously Thebes Formation) in the October basin within the Gulf of Suez region, are of particular interest for hydrocarbon exploitation. However, no efforts have been directed to investigate their petrophysical characteristics and pore system. This study aims to investigate the petrophysical characteristic, pore system and formation potentiality as a reservoir rock. Thirteen sidewall core samples and sixty thin sections from OCT-X well were studied in order to investigate the lithological characteristics, porosity network. In addition, well logging data and petrophysical and geochemical laboratories measurements including Nuclear Magnetic Resonance (NMR) porosity technique were used to define the petrophysical characteristics. The investigated work revealed that: 1) the pore system is a combination of depositional and diagenetic processes. 2) the dominant porosity types include fracture, inter-particle, intra-particle and moldic porosity; NMR indicates mesopores to macropores, 3) petrophysical evaluation and geochemical analysis indicates a self-sourced unconventional reservoir based on its organic richness characteristics unconventional resource opportunity as tight carbonate reservoir, 4) the basal part of the Radwany Formation has a high potential to store hydrocarbon, and it is a potential conventional resource. 6) The linking trends between the petrophysical parameters with sediment microfacies were defined in the studied section, where a significant increasing trend line has been inferred in the direction from wackestone microfacies to packstone microfacies. Finally, the diagenetic process through time has greatly controlled the petrophysical parameters of the Radwany Formation. The gap between Source and Reservoir rocks has been defined based on integrated geochemical and petrophysical characteristics. The studied section has unique multiscale characterization as unconventional and conventional resource.