bluuebunny/crossref_metadata_2025 huggingface dataset:
External Validation of the Briganti Nomogram to Predict Lymph Node Invasion in Prostate Cancer—Setting a New Threshold Value
Authors: Małkiewicz Bartosz , Ptaszkowski Kuba , Knecht Klaudia , Gurwin Adam , Wilk Karol , Kiełb Paweł , Dudek Krzysztof , Zdrojowy Romuald
Published: May 2021

(1) Introduction: The study aimed to test and validate the performance of the 2012 Briganti nomogram as a predictor for pelvic lymph node invasion (LNI) in men who underwent radical prostatectomy (RP) with extended pelvic lymph node dissection (PLND) to examine their performance and to analyse the therapeutic impact of using a different nomogram cut-off. (2) Material and Methods: The study group consisted of 222 men with clinically localized prostate cancer (PCa) who underwent RP with ePLND between 01/2012 and 10/2018. Measurements included: preoperative PSA, clinical stage (CS), primary and secondary biopsy Gleason pattern, and the percentage of positive cores. The area under the curve (AUC) of the receiver operator characteristic analysis was appointed to quantify the accuracy of the primary nomogram model to predict LNI. The extent of estimation associated with the use of this model was graphically depicted using calibration plots. (3) Results: The median number of removed lymph nodes was 16 (IQR 12–21). A total of 53 of 222 patients (23.9%) had LNI. Preoperative clinical and biopsy characteristics differed significantly (all p < 0.005) between men with and without LNI. A nomogram-derived cut-off of 7% could lead to a reduction of 43% (95/222) of lymph node dissection while omitting 19% (10/53) of patients with LNI. The sensitivity, specificity, and negative predictive value associated with the 7% cut-off were 81.1%, 50.3%, and 96.3%, respectively. (4) Conclusions: The analysed nomogram demonstrated high accuracy for LNI prediction. A nomogram-derived cut-off of 7% confirmed good performance characteristics within the first external validation cohort from Poland.
Comparative Analysis of the Intermolt and Postmolt Hepatopancreas Transcriptomes Provides Insight into the Mechanisms of Procambarus clarkii Molting Process
Authors: Su Shengyan , Munganga Brian Pelekelo , Tian Can , Li Jianlin , Yu Fan , Li Hongxia , Wang Meiyao , He Xinjin , Tang Yongkai
Published: May 2021

In the present study, we used RNA-Seq to investigate the expression changes in the transcriptomes of two molting stages (postmolt (M) and intermolt (NM)) of the red swamp crayfish and identified differentially expressed genes. The transcriptomes of the two molting stages were de novo assembled into 139,100 unigenes with a mean length of 675.59 bp. The results were searched against the NCBI, NR, KEGG, Swissprot, and KOG databases, to annotate gene descriptions, associate them with gene ontology terms, and assign them to pathways. Furthermore, using the DESeq R package, differentially expressed genes were evaluated. The analysis revealed that 2347 genes were significantly (p > 0.05) differentially expressed in the two molting stages. Several genes and other factors involved in several molecular events critical for the molting process, such as energy requirements, hormonal regulation, immune response, and exoskeleton formation were identified and evaluated by correlation and KEGG analysis. The expression profiles of transcripts detected via RNA-Seq were validated by real-time PCR assay of eight genes. The information presented here provides a transient view of the hepatopancreas transcripts available in the postmolt and intermolt stage of crayfish, hormonal regulation, immune response, and skeletal-related activities during the postmolt stage and the intermolt stage.
Automatic Determination of Secondary Dendrite Arm Spacing in AlSi-Cast Microstructures
Authors: Gawert Christian , Bähr Rüdiger
Published: May 2021

A new procedure for the automatic measurement of the secondary dendrite arm spacing (SDAS) from microscopic images is presented. The individual primary and secondary dendrite arms are identified through suitable segmentation techniques and clustered in such a way that dendritic structures are obtained suitable for SDAS measurement. The algorithms are applied to two different hypoeutectic aluminum cast alloys, and the quality of the measurements obtained is assessed through a comparison to manually measured SDAS values. A good agreement between the automated measurements and the distribution of manual measurements is found for both cast structures considered. In addition, a decrease in computation time is observed which allows for an increase in measurement density that is used to characterize the microstructures.
The Strong Laws of Large Numbers for Set-Valued Random Variables in Fuzzy Metric Space
Authors: Guan Li , Wei Juan , Min Hui , Zhang Junfei
Published: May 2021

In this paper, we firstly introduce the definition of the fuzzy metric of sets, and discuss the properties of fuzzy metric induced by the Hausdorff metric. Then we prove the limit theorems for set-valued random variables in fuzzy metric space; the convergence is about fuzzy metric induced by the Hausdorff metric. The work is an extension from the classical results for set-valued random variables to fuzzy metric space.
Qualitative Analyses of Differential Systems with Time-Varying Delays via Lyapunov–Krasovskiĭ Approach
Authors: Tunç Cemil , Tunç Osman , Wang Yuanheng , Yao Jen-Chih
Published: May 2021

In this paper, a class of systems of linear and non-linear delay differential equations (DDEs) of first order with time-varying delay is considered. We obtain new sufficient conditions for uniform asymptotic stability of zero solution, integrability of solutions of an unperturbed system and boundedness of solutions of a perturbed system. We construct two appropriate Lyapunov–Krasovskiĭ functionals (LKFs) as the main tools in proofs. The technique of the proofs depends upon the Lyapunov–Krasovskiĭ method. For illustration, two examples are provided in particular cases. An advantage of the new LKFs used here is that they allow to eliminate using Gronwall’s inequality. When we compare our results with recent results in the literature, the established conditions are more general, less restrictive and optimal for applications.
Analysis, Evaluation and Exact Tracking of the Finite Precision Error Generated in Arbitrary Number of Multiplications
Authors: Papaodysseus Constantin , Arabadjis Dimitris , Giannopoulos Fotios , Mamatsis Athanasios Rafail , Chalatsis Constantinos
Published: May 2021

In the present paper, a novel approach is introduced for the study, estimation and exact tracking of the finite precision error generated and accumulated during any number of multiplications. It is shown that, as a rule, this operation is very “toxic”, in the sense that it may force the finite precision error accumulation to grow arbitrarily large, under specific conditions that are fully described here. First, an ensemble of definitions of general applicability is given for the rigorous determination of the number of erroneous digits accumulated in any quantity of an arbitrary algorithm. Next, the exact number of erroneous digits produced in a single multiplication is given as a function of the involved operands, together with formulae offering the corresponding probabilities. In case the statistical properties of these operands are known, exact evaluation of the aforementioned probabilities takes place. Subsequently, the statistical properties of the accumulated finite precision error during any number of successive multiplications are explicitly analyzed. A method for exact tracking of this accumulated error is presented, together with associated theorems. Moreover, numerous dedicated experiments are developed and the corresponding results that fully support the theoretical analysis are given. Eventually, a number of important, probable and possible applications is proposed, where all of them are based on the methodology and the results introduced in the present work. The proposed methodology is expandable, so as to tackle the round-off error analysis in all arithmetic operations.
The Nexus between Sovereign CDS and Stock Market Volatility: New Evidence
Authors: Ballester Laura , Escrivá Ana Mónica , González-Urteaga Ana
Published: May 2021

This paper extends the studies published to date by performing an analysis of the causal relationships between sovereign CDS spreads and the estimated conditional volatility of stock indices. This estimation is performed using a vector autoregressive model (VAR) and dynamically applying the Granger causality test. The conditional volatility of the stock market has been obtained through various univariate GARCH models. This methodology allows us to study the information transmissions, both unidirectional and bidirectional, that occur between CDS spreads and stock volatility between 2004 and 2020. We conclude that CDS spread returns cause (in the Granger sense) conditional stock volatility, mainly in Europe and during the sovereign debt crisis. This transmission dynamic breaks down during the COVID-19 period, where there are high bidirectional relationships between the two markets.
Rapid Decrease in HDL-C in the Puberty Period of Boys Associated with an Elevation of Blood Pressure and Dyslipidemia in Korean Teenagers: An Explanation of Why and When Men Have Lower HDL-C Levels Than Women
Authors: Cho Kyung-Hyun , Kim Jae-Ryong
Published: May 2021

Low serum high-density lipoproteins-cholesterol (HDL-C) levels and high blood pressure are linked to each other and are recognized as independent risk factors of cardiovascular disease and dementia. HDL can cross the blood–brain barrier to remove amyloid plaque and the blood–testis barrier to supply cholesterol for spermatogenesis, but LDL cannot. During the teenage period, between 10 and 19 years of age, the systolic blood pressure (BP) increased gradually to 7.9% in boys (p < 0.001), but not in girls (p = 0.141). The boys’ group showed a remarkable decrease in the total cholesterol (TC) and HDL-C from 10 to 15 years of age (p < 0.001). After then, the TC level increased again at 19 years of age to the previous level (p < 0.001). On the other hand, the HDL-C level at 19 years of age in the boys’ group was not restored to the previous level at 10 years of age. The girls’ group maintained similar TC (p < 0.001) and HDL-C (p < 0.001) levels from 10 to 19 years of age. These results suggest there was a remarkable difference in cholesterol consumption, particularly in the HDL-C level between boys and girls during the pubertal period. Correlation analysis showed an inverse association between the HDL-C level and SBP in boys (r = −0.133, p < 0.001) and girls (r = −0.065, p = 0.009) from 10 to 19 years of age. Interestingly, only the boys’ group showed an inverse association with the diastolic BP (r = −0.122, p < 0.001); the girls’ group did not have such an association (r = −0.016, p = 0.516). In conclusion, the boys’ group showed a sharp decrease in the HDL-C level from 10 to 15 years of age, whereas the girls’ group showed an increase in the HDL-C level during the same period. These results explain why men have a lower serum HDL-C level than women in adulthood.
Preparation of Perfluorosulfonated Ionomer Nanofibers by Solution Blow Spinning
Authors: Shinkawa Masahiro , Motai Kazunori , Eguchi Keita , Takarada Wataru , Ashizawa Minoru , Masunaga Hiroyasu , Ohta Noboru , Hayamizu Yuhei , Matsumoto Hidetoshi
Published: May 2021

In this work, we report the preparation of high-purity perfluorosulfonated ionomer (Nafion) nanofibers (NFs) via solution blow spinning (SBS). Fiber formation in solution jet spinning is strongly dependent on the structure of the spinning solution. Upon adding a small amount of poly(ethyleneoxide) (PEO) as a spinning aid to Nafion dispersion, most of the highly ordered Nafion aggregate disappeared, allowing the stable production of bead-free and smooth high-purity NFs (Nafion/PEO = 99/1) by SBS. The microstructure of the blowspun Nafion NFs differed from that of electrospun NFs. In the blowspun NFs, incomplete microphase separation between hydrophilic (ionic) and hydrophobic domains was observed, but the crystallization of CF2−CF2 chains was enhanced owing to the high extensional strain rate and rapid solidification during SBS. These findings provide fundamental information for the preparation and characterization of blowspun Nafion NFs.
Acid Mine Drainage Dynamics from a Paste Tailing Deposit: Effect of Sulfate Content on the Consistency and Chemical Stability after Storage
Authors: Leiva Eduardo , Cayazzo María , Dávila Luis , Torres Mario , Ledezma Christian
Published: May 2021

Surface paste tailings’ disposal has emerged recently as an optimal and efficient method to favor tailings’ self-containment after being deposited into dams. This disposal method can improve the reuse of water and reduce the generation of acid mine drainage (AMD) and the release of leachates (e.g., acid and heavy metals). However, the implications of chemical factors or mixed-water chemistry in the stability of paste tailings over time are not clear. In this work, we evaluated the release of sulfate from tailing samples and the role of sulfate as a critical factor in the tailings’ strength, consistency, and stability. Our results showed that the release of acid runoff with high sulfate load from the tailings is negligible. Leaching tests were performed for 180 days and did not show a significant release of sulfate, heavy metals, or acid waters. However, the presence of sulfate salts derived from the binders used in the pretreatment of the paste tailings shows an impact on the tailings’ consistency. Undrained triaxial monotonic compression tests revealed low effective cohesion forces in the tailings samples. In addition, it was observed that, in tailings slurries prepared with varying concentrations of sulfate (0, 500, and 1000 mg/L), the slump test value dropped Δ−55% when the sulfate concentration increased from 0 to 1000 mg/L. These results support the idea that the presence of sulfate within the tailings could be relevant for the paste consistency after storage. This knowledge will contribute to a better understanding of the critical chemical factors that affect the stability of paste tailings over time.
Characterization of Iron-Matrix Composites Reinforced by In Situ TiC and Ex Situ WC Fabricated by Casting
Authors: Moreira Aida B. , Ribeiro Laura M. M. , Lacerda Pedro , Vieira Manuel F.
Published: May 2021

In this study, the effect of microstructural characteristics on the mechanical properties of high-chromium white cast iron-matrix composites reinforced by in situ TiC and ex situ WC was investigated. To this end, two different powder mixtures (Ti + Al + graphite and WC + Fe) were compressed to produce green compacts that were inserted into the mold, before casting. The microstructure of the resulting composites and the base metal was characterized using optical microscopy (OM) and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS). The microstructural analysis revealed a sound bonding between the composite zone and the base metal. The reinforcement with WC particles showed a homogeneous distribution of the carbide particles, unlike the reinforcement with TiC particles. The mechanical properties of the reinforcements were evaluated using hardness and ball-cratering micro-abrasion tests. The results showed that both reinforcements increase the hardness and wear performance of the base material, which was the best performance achieved by the reinforcement with WC particles.
Gear Root Bending Strength: A New Multiaxial Approach to Translate the Results of Single Tooth Bending Fatigue Tests to Meshing Gears
Authors: Concli Franco , Fraccaroli Lorenzo , Maccioni Lorenzo
Published: May 2021

Developing accurate design data to enable the effective use of new materials is undoubtedly an essential goal in the gear industry. To speed up this process, Single Tooth Bending Fatigue (STBF) tests can be conducted. However, STBF tests tend to overestimate the material properties with respect to tests conducted on Running Gears (RG). Therefore, it is common practice to use a constant correction factor fkorr, of value 0.9 to exploit STBF results to design actual gears, e.g., through ISO 6336. In this paper, the assumption that this coefficient can be considered independent from the gear material, geometry, and loading condition was questioned, and through the combination of numerical simulations with a multiaxial fatigue criterion, a method for the calculation of fkorr was proposed. The implementation of this method using different gear geometries and material properties shows that fkorr varies with the gears geometrical characteristics, the material fatigue strength, and the load ratio (R) set in STBF tests. In particular, by applying the Findley criterion, it was found that, for the same gear geometry, fkorr depends on the material as well. Specifically, fkorr increases with the ratio between the bending and torsional fatigue limits. Moreover, through this method it was shown that the characteristics related to the material and the geometry have a relevant effect in determining the critical point (at the tooth root) where the fracture nucleates.
Influence of Mg Content on Texture Development during Hot Plain-Strain Deformation of Aluminum Alloys
Authors: Aryshenskii Evgenii , Hirsch Jurgen , Konovalov Sergey , Aryshenskii Vladimir , Drits Alexander
Published: May 2021

The study addresses the effect of magnesium and other alloying elements on rolling “β-fiber” texture formation during hot deformation of aluminum alloys. For the study, flat cast ingots from three aluminum alloys with variable magnesium content were deformed in a Gleeble testing unit with different parameters of thermomechanical treatment. Immediately after completion of deformation, the samples were quenched using an automatic cooling system and the microstructure and crystalline texture was analyzed by optical microscopy and X-ray analysis. The analysis demonstrated that an increase in alloying components, magnesium in particular, leads to an increase in brass-type texture and a decrease in S and copper-type texture. The reason was that the simulation of the deformation texture development revealed a great contribution of impurity atoms rather than the decrease in stacking fault energy.
Identity of blaCTX-M Carrying Plasmids in Sequential ESBL-E. coli Isolates from Patients with Recurrent Urinary Tract Infections
Authors: Karami Nahid , KK Sriram , Yazdanshenas Shora , Lin Yii-Lih , Jaén-Luchoro Daniel , Ekedahl Elina , Parameshwaran Sanjana , Lindblom Anna , Åhrén Christina , Westerlund Fredrik
Published: May 2021

Plasmid-mediated multidrug resistance in E. coli is becoming increasingly prevalent. Considering this global threat to human health, it is important to understand how plasmid-mediated resistance spreads. From a cohort of 123 patients with recurrent urinary tract infections (RUTI) due to extended spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL E. coli), only five events with a change of ESBL E. coli strain between RUTI episodes were identified. Their blaCTX-M encoding plasmids were compared within each pair of isolates using optical DNA mapping (ODM) and PCR-based replicon typing. Despite similar blaCTX-M genes and replicon types, ODM detected only one case with identical plasmids in the sequential ESBL E. coli strains, indicating that plasmid transfer could have occurred. For comparison, plasmids from seven patients with the same ESBL E. coli strain reoccurring in both episodes were analyzed. These plasmids (encoding blaCTX-M-3, blaCTX-M-14, and blaCTX-M-15) were unaltered for up to six months between recurrent infections. Thus, transmission of blaCTX-M plasmids appears to be a rare event during the course of RUTI. Despite the limited number (n = 23) of plasmids investigated, similar blaCTX-M-15 plasmids in unrelated isolates from different patients were detected, suggesting that some successful plasmids could be associated with specific strains, or are more easily transmitted.
Lactiplantibacillus plantarum MG4296 and Lacticaseibacillus paracasei MG5012 Ameliorates Insulin Resistance in Palmitic Acid-Induced HepG2 Cells and High Fat Diet-Induced Mice
Authors: Won Gayeong , Choi Soo-Im , Kang Chang-Ho , Kim Gun-Hee
Published: May 2021

The purpose of this study was to evaluate the capacity of Lactiplantibacillus plantarum MG4296 (MG4296) and Lacticaseibacillus paracasei MG5012 (MG5012) on insulin resistance (IR) and diabetes-related metabolic changes in palmitic acid (PA)-induced HepG2 cells and high-fat diet-induced mice. In vitro, cell-free extracts of MG4296 and MG5012 alleviated IR by increasing glucose uptake and glycogen content in PA-induced insulin-resistant HepG2 cells. In vivo, MG4296 and MG5012 supplementation markedly decreased body weight and glucose tolerance. Administration of both strains also improved serum glucose, glycated hemoglobin, insulin, triglyceride, LDL/HDL ratio, and homeostatic model assessment of IR (HOMA-IR). Histopathological analysis of liver tissue demonstrated a significant reduction in lipid accumulation and glycogen content. Moreover, MG4296 and MG5012 treatment enhanced phosphoinositide-3 kinase (PI3K)/protein kinase B (Akt) expression in the liver. Overall, MG4296 and MG5012 could prevent HFD-induced glucose tolerance and hyperglycemia by improving IR. Therefore, L. plantarum MG4296 and L. paracasei MG5012 could be useful as new probiotics candidates to improve T2DM.
Garlic Essential Oil as Promising Option for the Treatment of Acute Campylobacteriosis—Results from a Preclinical Placebo-Controlled Intervention Study
Authors: Heimesaat Markus M. , Mousavi Soraya , Weschka Dennis , Bereswill Stefan
Published: May 2021

Since human infections with Campylobacter jejuni including antibiotic-resistant strains are rising worldwide, natural compounds might constitute promising antibiotics-independent treatment options for campylobacteriosis. Since the health-beneficial properties of garlic have been known for centuries, we here surveyed the antimicrobial and immune-modulatory effects of garlic essential oil (EO) in acute experimental campylobacteriosis. Therefore, secondary abiotic IL-10-/- mice were orally infected with C. jejuni strain 81-176 and garlic-EO treatment via the drinking water was initiated on day 2 post-infection. Mice from the garlic-EO group displayed less severe clinical signs of acute campylobacteriosis as compared to placebo counterparts that were associated with lower ileal C. jejuni burdens on day 6 post-infection. Furthermore, when compared to placebo application, garlic-EO treatment resulted in alleviated colonic epithelia cell apoptosis, in less pronounced C. jejuni induced immune cell responses in the large intestines, in dampened pro-inflammatory mediator secretion in intestinal and extra-intestinal compartments, and, finally, in less frequent translocation of viable pathogens from the intestines to distinct organs. Given its potent immune-modulatory and disease-alleviating effects as shown in our actual preclinical placebo-controlled intervention study, we conclude that garlic-EO may be considered as promising adjunct treatment option for acute campylobacteriosis in humans.
Clean and Feasible Utilization of High Silica Fluorspar Powder via Reverse Flotation: A Pilot Study
Authors: Zhang Chenhu , Gao Jiande , Hu Yuehua , Sun Wei , Lv Fei , Liu Zhenjun
Published: May 2021

Fluorite is a nonrenewable mineral used to produce anhydrous hydrofluoric acid (AHF) and aluminum fluoride. The demand for low-grade fluorite powder (CaF2 < 97%) has fallen sharply owing to the current market conditions. Therefore, a large number of fluorite concentrates have been improved by acid leaching. While this approach can efficiently remove CaCO3 from fluorite concentrate, the SiO2 content, which significantly affects AHF consumption during the production of HF or aluminum fluoride, cannot be completely removed. To solve this problem, in this study, we used reverse flotation before leaching the fluorite concentrates. Subsequently, the feasibility of reverse flotation desilication was determined. The obtained results of the ZP (zeta potential) measurements, solution chemistry analysis, FTIR (Fourier transform infrared spectroscopy) analysis, and micro-flotation tests indicated that employing dodecylamine as the collector and citric acid as the depressor could effectively separate sericite from fluorite. The batch flotation experiment and the pilot test were conducted in Chenzhou (Hunan, China) followed by their operation in Xinyuan Mining Co. Ltd., which produces monolithic fluorite ore on the large scale in Asia. Notably, we found that the contents of both SiO2 and Al2O3 were from 2.82%, 1.17% reduced to 1.28%, 0.74% in the batch flotation experiment. The results of the pilot test showed that the new reverse flotation + leaching technology could dramatically reduce the potential environmental impact and costs, thereby significantly improving the economic benefits by satisfying the requirements of the market.
Oxidation Roasting of Fine-Grained Carbonaceous Gold Ore: The Effect of Aeration Rate
Authors: Li Hui , Xiao Wei , Jin Jianping , Han Yuexin
Published: May 2021

The oxidation roasting of carbon-bearing micro-fine gold can eliminate or weaken the robbing effect of carbonaceous materials and clay, and destroy the encapsulation of micro-fine gold. The micropores produced by gas escaping during the roasting process are conducive to the diffusion of leaching agents, thus enhancing the cyanide leaching of gold. In this paper, the influence of the aeration rate during roasting on the leaching rate of fine-grained carbonaceous gold ore and its mechanism were studied using thermodynamic calculations, crystal structure analysis, surface chemical groups and bonds analysis, microporous structure analysis, and surface morphology detection. Under suitable roasting conditions, the carbonaceous and pyrite in the ore are oxidized, while carbonate minerals such as dolomite and calcite as well as clay minerals are decomposed, and the gold-robbing materials lose their activity. The experimental results have theoretical and practical significance for the popularization and application of oxidation roasting technology of fine carbon-bearing gold ore.
Application of Nanotechnology for Sensitive Detection of Low-Abundance Single-Nucleotide Variations in Genomic DNA: A Review
Authors: Mukhtar Mahwash , Sargazi Saman , Barani Mahmood , Madry Henning , Rahdar Abbas , Cucchiarini Magali
Published: May 2021

Single-nucleotide polymorphisms (SNPs) are the simplest and most common type of DNA variations in the human genome. This class of attractive genetic markers, along with point mutations, have been associated with the risk of developing a wide range of diseases, including cancer, cardiovascular diseases, autoimmune diseases, and neurodegenerative diseases. Several existing methods to detect SNPs and mutations in body fluids have faced limitations. Therefore, there is a need to focus on developing noninvasive future polymerase chain reaction (PCR)–free tools to detect low-abundant SNPs in such specimens. The detection of small concentrations of SNPs in the presence of a large background of wild-type genes is the biggest hurdle. Hence, the screening and detection of SNPs need efficient and straightforward strategies. Suitable amplification methods are being explored to avoid high-throughput settings and laborious efforts. Therefore, currently, DNA sensing methods are being explored for the ultrasensitive detection of SNPs based on the concept of nanotechnology. Owing to their small size and improved surface area, nanomaterials hold the extensive capacity to be used as biosensors in the genotyping and highly sensitive recognition of single-base mismatch in the presence of incomparable wild-type DNA fragments. Different nanomaterials have been combined with imaging and sensing techniques and amplification methods to facilitate the less time-consuming and easy detection of SNPs in different diseases. This review aims to highlight some of the most recent findings on the aspects of nanotechnology-based SNP sensing methods used for the specific and ultrasensitive detection of low-concentration SNPs and rare mutations.
Bismuth Doping in Nanostructured Tetrahedrite: Scalable Synthesis and Thermoelectric Performance
Authors: Baláž Peter , Guilmeau Emmanuel , Achimovičová Marcela , Baláž Matej , Daneu Nina , Dobrozhan Oleksandr , Kaňuchová Mária
Published: May 2021

In this study, we demonstrate the feasibility of Bi-doped tetrahedrite Cu12Sb4−xBixS13 (x = 0.02–0.20) synthesis in an industrial eccentric vibratory mill using Cu, Sb, Bi and S elemental precursors. High-energy milling was followed by spark plasma sintering. In all the samples, the prevailing content of tetrahedrite Cu12Sb4S13 (71–87%) and famatinite Cu3SbS4 (13–21%), together with small amounts of skinnerite Cu3SbS3, have been detected. The occurrence of the individual Cu-Sb-S phases and oxidation states of bismuth identified as Bi0 and Bi3+ are correlated. The most prominent effect of the simultaneous milling and doping on the thermoelectric properties is a decrease in the total thermal conductivity (κ) with increasing Bi content, in relation with the increasing amount of famatinite and skinnerite contents. The lowest value of κ was achieved for x = 0.2 (1.1 W m−1 K−1 at 675 K). However, this sample also manifests the lowest electrical conductivity σ, combined with relatively unchanged values for the Seebeck coefficient (S) compared with the un-doped sample. Overall, the lowered electrical performances outweigh the benefits from the decrease in thermal conductivity and the resulting figure-of-merit values illustrate a degradation effect of Bi doping on the thermoelectric properties of tetrahedrite in these synthesis conditions.
LTDA-MAC v2.0: Topology-Aware Unsynchronized Scheduling in Linear Multi-Hop UWA Networks
Authors: Morozs Nils , Mitchell Paul D. , Zakharov Yuriy
Published: May 2021

This paper investigates the use of underwater acoustic sensor networks (UASNs) for subsea asset monitoring. In particular, we focus on the use cases involving the deployment of networks with line topologies, e.g., for monitoring oil and gas pipelines. The Linear Transmit Delay Allocation MAC (LTDA-MAC) protocol facilitates efficient packet scheduling in linear UASNs without clock synchronization at the sensor nodes. It is based on the real-time optimization of a packet schedule for a given network deployment. In this paper, we present a novel greedy algorithm for real-time optimization of LTDA-MAC schedules. It produces collision-free schedules with significantly shorter frame duration, and is 2–3 orders of magnitude more computationally efficient than our previously proposed solution. Simulations of a subsea pipeline monitoring scenario show that, despite no clock synchronization, LTDA-MAC equipped with the proposed schedule optimization algorithm significantly outperforms Spatial TDMA.
Dual-Output Mode Analysis of Multimode Laguerre-Gaussian Beams via Deep Learning
Authors: Yuan Xudong , Xu Yaguang , Zhao Ruizhi , Hong Xuhao , Lu Ronger , Feng Xia , Chen Yongchuang , Zou Jincheng , Zhang Chao , Qin Yiqiang , Zhu Yongyuan
Published: May 2021

The Laguerre-Gaussian (LG) beam demonstrates great potential for optical communication due to its orthogonality between different eigenstates, and has gained increased research interest in recent years. Here, we propose a dual-output mode analysis method based on deep learning that can accurately obtain both the mode weight and phase information of multimode LG beams. We reconstruct the LG beams based on the result predicted by the convolutional neural network. It shows that the correlation coefficient values after reconstruction are above 0.9999, and the mean absolute error (MAE) of the mode weights and phases are about 1.4 × 10−3 and 2.9 × 10−3, respectively. The model still maintains relatively accurate prediction for the associated unknown data set and the noise-disturbed samples. In addition, the computation time of the model for a single test sample takes only 0.975 ms on average. These results show that our method has good abilities of generalization and robustness and allows for nearly real-time modal analysis.
Culturable Seed Microbiota of Populus trichocarpa
Authors: Heitmann Sabrina , Bergmann Gillian E. , Barge Edward , Ridout Mary , Newcombe George , Busby Posy E.
Published: May 2021

Plants harbor a diverse community of microbes, whose interactions with their host and each other can influence plant health and fitness. While microbiota in plant vegetative tissues has been extensively studied, less is known about members of the seed microbiota. We used culture-based surveys to identify bacteria and fungi found in the seeds of the model tree, Populus trichocarpa, collected from different sites. We found that individual P. trichocarpa seeds typically contained zero or one microbe, with common taxa including species of Cladosporium, Aureobasidium, Diaporthe, Alternaria, and Pseudomonas, a bacterium. Pseudomonas isolates were associated with seed mortality and were negatively associated with the occurrence of fungal isolates within Epicoccum, Alternaria, and Aureobasidium from the same seed. Next, we conducted an inoculation experiment with one of the isolated seed microbes, Pseudomonas syringae pv. syringae, and found that it reduced seed germination and increased seedling mortality for P. trichocarpa. Our findings highlight common fungi and bacteria in the seeds of P. trichocarpa, prompting further study of their functional consequences. Moreover, our study confirms that P. syringae pv. syringae is a seed pathogen of P. trichocarpa and is the first report that P. syringae pv. syringae is a lethal seedling pathogen of P. trichocarpa, allowing for future work on the pathogenicity of this bacterium in seedlings and potential antagonism with other seed microbes.
Development of Non-Ethoxypropanoic Acid Type Cryptochrome Inhibitors with Circadian Molecular Clock-Enhancing Activity by Bioisosteric Replacement
Authors: Jeong Yong Uk , Jin Hyo-Eon , Lim Hye Young , Choi Goyeong , Joo Hansol , Kang Bohun , Lee Ga-Hyun , Liu Kwang-Hyeon , Maeng Han-Joo , Chung Sooyoung , Son Gi Hoon , Jung Jong-Wha
Published: May 2021

Circadian dysfunction is closely associated with an increased risk of various diseases. Considering that molecular clock machinery serves as an intrinsic time-keeping system underlying the circadian rhythm of biological processes, the modulation of the molecular clock machinery is an attractive therapeutic target with novel mechanisms of action. Based on the previous structure–activity relationship study of small molecule cryptochrome (CRY) inhibitors possessing an ethoxypropanoic acid moiety, non-ethoxypropanoic acid-type inhibitors have been developed by bioisosteric replacement. They were evaluated as potent and effective enhancers of E-box-mediated transcription, and, in particular, ester 5d and its hydrolysis product 2d exhibited desirable metabolic and pharmacokinetic profiles as promising drug candidates. Compound 2d directly bound to both CRY1 and 2 in surface plasmon resonance analyses, suggesting that the molecular target is CRY. Effects of compound 5d and 2d on suppressive action of CRY1 on CLOCK:BMAL1-activated E-box-LUC reporter activity revealed that both compounds inhibited the negative feedback actions of CRY on CLOCK:BMAL1. Most importantly, compounds 5d and 2d exhibited significant effects on molecular circadian rhythmicity to be considered circadian clock-enhancers, distinct from the previously developed CRY inhibitors possessing an ethoxypropanoic acid moiety.
Second-Order Dispersion Sensor Based on Multi-Plasmonic Surface Resonances in D-Shaped Photonic Crystal Fibers
Authors: Cardoso Markos , Silva Anderson , Romeiro Amanda , Giraldi M. , Costa João , Santos José , Baptista José , Guerreiro Ariel
Published: May 2021

This paper proposes a scheme to determine the optical dispersion properties of a medium using multiple localized surface plasmon resonances (SPR) in a D-shaped photonic crystal fiber (PCF) whose flat surface is covered by three adjacent gold layers of different thicknesses. Using computational simulations, we show how to customize plasmon resonances at different wavelengths, thus allowing for obtaining the second-order dispersion. The central aspect of this sensing configuration is to balance miniaturization with low coupling between the different localized plasmon modes in adjacent metallic nanostructures. The determination of the optical dispersion over a large spectral range provides information on the concentration of different constituents of a medium, which is of paramount importance when monitoring media with time-varying concentrations, such as fluidic media.
Electron Dynamics and Thomson Scattering for Ultra-Intense Lasers: Elliptically Polarized and OAM Beams
Authors: Pastor Ignacio , Álvarez-Estrada Ramón F. , Roso Luis , Guasp José , Castejón Francisco
Published: May 2021

We investigated the classical nonlinear Thomson scattering (TS), from a single relativistic electron, generated by either: (a) an incoming plane wave monochromatic laser radiation and general elliptical polarization or (b) incoming radiations with intrinsic orbital angular momentum (OAM). Both (a) and (b) propagate along the z direction, with wave vector k0, frequency ω0, and initial phase φ0≠0 and have any intensity. Item (a) enables obtaining general electron TS Doppler frequencies and other quantities, for fusion plasmas. We explored the possibility of approximating nonlinear TS with OAM beams (Item (b)) by means of nonlinear TS with plane wave beams (Item (a)). For Item (a), a general explicit solution of the Lorentz relativistic equation and the subsequent TS are given in terms of ζ=ω0t−k0z (t denoting time). In particular, it includes the cases for linear and circular polarizations and φ0≠0 for fusion plasmas, thereby extending previous studies for φ0=0. The explicit solutions give rise to very efficient computations of electron TS Doppler frequencies, periods of trajectories, and drift velocities, and the comparisons with ab initio numerical solutions (for Item (a)) yield an excellent match. The approximate approach, using explicit solutions for Item (a), towards TS OAM (employing ab initio numerical computations for Item (b)), extending previously reported ones) yields a quite satisfactory agreement over time spans including several optical cycles, for a wide range of laser intensities, polarizations, and electron energies. The role of φ0≠0 was analyzed. A simple quantitative criterion to predict whether the agreement between the two approaches (a) and (b) would be observed over a given time span is discussed.
High Field Single- to Few-Cycle THz Generation with Lithium Niobate
Authors: Zhu Xing , Bacon David R. , Madéo Julien , Dani Keshav M.
Published: May 2021

The transient terahertz (THz) pulse with high peak field has become an important tool for matter manipulation, enabling many applications such as nonlinear spectroscopy, particle acceleration, and high harmonic generation. Among the widely used THz generation techniques, optical rectification in lithium niobate (LN) has emerged as a powerful method to achieve high fields at low THz frequencies, suitable to exploring novel nonlinear phenomena in condensed matter systems. In this review, we focus on introducing single- to few-cycle THz generation in LN, including the basic principles, techniques, latest developments, and current limitations. We will first discuss the phase matching requirements of LN, which leads to Cherenkov-like radiation, and the tilted pulse front (TPF) technique. Emphasis will be put on the TPF technique, which has been shown to improve THz generation efficiency, but still has many limitations. Different geometries used to produce continuous and discrete TPF will be systematically discussed. We summarize the advantages and limitations of current techniques and future trends.
Synthesis of Optically Tunable and Thermally Stable PMMA–PVA/CuO NPs Hybrid Nanocomposite Thin Films
Authors: Alsaad Ahmad M. , Ahmad Ahmad A. , Qattan Issam A. , El-Ali Abdul-Raouf , Fawares Shatha A. Al , Al-Bataineh Qais M.
Published: May 2021

We report the synthesis and comprehensive characterization of polymethylmethacrylate (PMMA)/polyvinylalcohol (PVA) polymeric blend doped with different concentrations of Copper oxide (CuO) nanoparticles (NPs). The PMMA–PVA/CuO nanocomposite hybrid thin films containing wt.% = 0%, 2%, 4%, 8%, and 16% of CuO NPs are deposited on glass substrates via dip-coating technique. Key optical parameters are measured, analyzed, and interpreted. Tauc, Urbach, Spitzer–Fan, and Drude models are employed to calculate the optical bandgap energy (Eg) and the optoelectronic parameters of PMMA–PVA/CuO nanocomposites. The refractive index and Eg of undoped PMMA–PVA are found to be (1.5–1.85) and 4.101 eV, respectively. Incorporation of specific concentrations of CuO NPs into PMMA–PVA blend leads to a considerable decrease in Eg and to an increase of the refractive index. Moreover, Fourier Transform Infrared Spectroscopy (FTIR) transmittance spectra are measured and analyzed for undoped and doped polymeric thin films to pinpoint the major vibrational modes in the spectral range (500 and 4000 cm−1) as well as to elucidate the nature of chemical network bonding. Thermogravimetric analysis (TGA) is conducted under appropriate conditions to ensure the thermal stability of thin films. Doped polymeric thin films are found to be thermally stable below 105 °C. Therefore, controlled tuning of optoelectronic and thermal properties of doped polymeric thin films by introducing an appropriate concentration of inorganic fillers leads to a smart design of scaled multifunctional devices.
Hydrophilicity Affecting the Enzyme-Driven Degradation of Piezoelectric Poly-l-Lactide Films
Authors: Gazvoda Lea , Višić Bojana , Spreitzer Matjaž , Vukomanović Marija
Published: May 2021

Biocompatible and biodegradable poly-l-lactic acid (PLLA) processed into piezoelectric structures has good potential for use in medical applications, particularly for promoting cellular growth during electrostimulation. Significant advantages like closer contacts between cells and films are predicted when their surfaces are modified to make them more hydrophilic. However, there is an open question about whether the surface modification will affect the degradation process and how the films will be changed as a result. For the first time, we demonstrate that improving the polymer surface’s wettability affects the position of enzyme-driven degradation. Although it is generally considered that proteinase K degrades only the polymer surface, we observed the enzyme’s ability to induce both surface and bulk degradation. In hydrophilic films, degradation occurs at the surface, inducing surface erosion, while for hydrophobic films, it is located inside the films, inducing bulk erosion. Accordingly, changes in the structural, morphological, mechanical, thermal and wetting properties of the film resulting from degradation vary, depending on the film’s wettability. Most importantly, the degradation is gradual, so the mechanical and piezoelectric properties are retained during the degradation.
Improved Copper–Epoxy Adhesion by Laser Micro- and Nano-Structuring of Copper Surface for Thermal Applications
Authors: Mora Mario , Amaveda Hippolyte , Porta-Velilla Luis , de la Fuente Germán F. , Martínez Elena , Angurel Luis A.
Published: May 2021

The objective of this work is the enhancement of metal-to-metal bonding to provide high thermal conductivity together with electrical insulation, to be used as heat sinks at room and cryogenic temperatures. High thermal conductive metal (copper) and epoxy resin (Stycast 2850FT) were used in this study, with the latter also providing the required electrical insulation. The copper surface was irradiated with laser to induce micro- and nano-patterned structures that result in an improvement of the adhesion between the epoxy and the copper. Thus, copper-to-copper bonding strength was characterized by means of mechanical tensile shear tests. The effect of the laser processing on the thermal conductivity properties of the Cu/epoxy/Cu joint at different temperatures, from 10 to 300 K, is also reported. Using adequate laser parameters, it is possible to obtain high bonding strength values limited by cohesive epoxy fracture, together with good thermal conductivity at ambient and cryogenic temperatures.
Lifetime Prediction Using a Tribology-Aware, Deep Learning-Based Digital Twin of Ball Bearing-Like Tribosystems in Oil and Gas
Authors: Desai Prathamesh S. , Granja Victoria , Higgs C. Fred
Published: May 2021

The recent decline in crude oil prices due to global competition and COVID-19-related demand issues has highlighted the need for the efficient operation of an oil and gas plant. One such avenue is accurate predictions about the remaining useful life (RUL) of components used in oil and gas plants. A tribosystem is comprised of the surfaces in relative motion and the lubricant between them. Lubricant oils play a significant role in keeping any tribosystem such as bearings and gears working smoothly over the lifetime of the oil and gas plant. The lubricant oil needs replenishment from time to time to avoid component breakdown due to the increased presence of wear debris and friction between the sliding surfaces of bearings and gears. Traditionally, this oil change is carried out at pre-determined times. This paper explored the possibilities of employing machine learning to predict early failure behavior in sensor-instrumented tribosystems. Specifically, deep learning and tribological data obtained from sensors deployed on the components can provide more accurate predictions about the RUL of the tribosystem. This automated maintenance can improve the overall efficiency of the component. The present study aimed to develop a deep learning-based digital twin for accurately predicting the RUL of a tribosystem comprised of a ball bearing-like test apparatus, a four-ball tester, and lubricant oil. A commercial lubricant used in the offshore oil and gas components was tested for its extreme pressure performance, and its welding load was measured using a four-ball tester. Three accelerated deterioration tests was carried out on the four-ball tester at a load below the welding load. Based on the wear scar measurements obtained from the experimental tests, the RUL data were used to train a multivariate convolutional neural network (CNN). The training accuracy of the model was above 99%, and the testing accuracy was above 95%. This work involved the model-free learning prediction of the remaining useful lifetime of ball bearing-type contacts as a function of key sensor input data (i.e., load, friction, temperature). This model can be deployed for in-field tribological machine elements to trigger automated maintenance without explicitly measuring the wear phenomenon.