bluuebunny/crossref_metadata_2025 huggingface dataset:
Remarkable Species Diversity of the Leafhopper Genus Xestocephalus (Hemiptera: Cicadellidae: Aphrodinae) in Thailand
Authors: Liang Zonglei , Dietrich Christopher H. , Dai Wu
Published: June 2021

Xestocephalus Van Duzee is among the most common and widespread genera of Cicadellidae in the temperate and tropical regions of the world. In the present study, 205 specimens of the genus Xestocephalus were collected in Thailand, whereas only a single species of the genus was recorded previously using Malaise trap field sampling, studied by comparative morphology. Seventeen species were recognized, including twelve new species: X. binarius sp. nov., X. chrysanthemum sp. nov., X. cowboyocreus sp. nov., X. densprint sp. nov., X. dimiprocessus sp. nov., X. exproiecturus sp. nov., X. gracilus sp. nov., X. limpidissimus sp. nov., X. malleus sp. nov., X. nonattribus sp. nov., X. recipinams sp. nov., and X. tenusis Liang sp. nov. Four species were recorded in Thailand for the first time: Xestocephalus abyssinicus Heller and Linnavuori, Xestocephalus asper Linnavuori, Xestocephalus ishidae Matsumura, and Xestocephalus toroensis Matsumura. Detailed morphological descriptions of all 17 species are given; photographs of external habitus and male genitalia of the species from Thailand are provided. A checklist of species of the genus is also given, and a key to all Thailand Xestocephalus species is also provided.
Association between Skin Cancer and Systemic and Ocular Comorbidities in South Korea
Authors: Lee Sul Hee , Ro Jun-Soo , Chung Kee Yang , Lee Sang Hoon , Park Young Lip , Kim Jung Eun , Lee Si Hyung
Published: June 2021

Background: In this study, we investigated the associations between various systemic and ocular comorbidities and skin cancer, in a nationwide cohort of South Koreans. Method: We reviewed the data of 1,103,302 individuals in the South Korean National Health Insurance Service-National Sample Cohort database from 2002 to 2015. Of these, 1202 individuals diagnosed with skin cancer from 2004 were included in the study group. The control group was matched in a 1:5 ratio based on propensity scores. Results: The prevalence rates of melanoma and non-melanoma skin cancer increased from 2004 to 2015. Multivariate logistic regression analysis revealed that, among the various systemic conditions, hypertension was significantly associated with skin cancer, while among ocular comorbidities, macular degeneration showed a significant association with skin cancer. Conclusions: This is the first study to demonstrate associations between skin cancer and various systemic and ocular comorbidities. The results suggest that hypertension and macular degeneration may increase the risk of skin cancer development, or vice versa. Further studies are needed to evaluate the causal relationships between these conditions.
Conditional CT Strategy—An Effective Tool to Reduce Negative Appendectomy Rate and the Overuse of the CT
Authors: Luksaite-Lukste Raminta , Kliokyte Ruta , Samuilis Arturas , Jasiunas Eugenijus , Luksta Martynas , Strupas Kestutis , Poskus Tomas
Published: June 2021

(1) Background: Diagnosis of acute appendicitis (AA) remains challenging; either computed tomography (CT) is universally used or negative appendectomy rates of up to 30% are reported. Transabdominal ultrasound (TUS) as the first-choice imaging modality might be useful in adult patients to reduce the need for CT scans while maintaining low negative appendectomy (NA) rates. The aim of this study was to report the results of the conditional CT strategy for the diagnosis of acute appendicitis. (2) Methods: All patients suspected of acute appendicitis were prospectively registered from 1 January 2016 to 31 December 2018. Data on their clinical, radiological and surgical outcomes are presented. (3) Results: A total of 1855 patients were enrolled in our study: 1206 (65.0%) were women, 649 (35.0%) were men, and the median age was 34 years (IQR, 24.5–51). TUS was performed in 1851 (99.8%) patients, and CT in 463 (25.0%) patients. Appendices were not visualized on TUS in 1320 patients (71.3%). Furthermore, 172 (37.1%) of 463 CTs were diagnosed with AA, 42 (9.1%) CTs revealed alternative emergency diagnosis and 249 (53.8%) CTs were normal. Overall, 519 (28.0%) patients were diagnosed with AA: 464 appendectomies and 27 diagnostic laparoscopies were performed. The NA rate was 4.2%. The sensitivity and specificity for TUS and CT are as follows: 71.4% and 96.2%; 93.8% and 93.6%. (4) Conclusion: A conditional CT strategy is effective in reducing NA rates and avoids unnecessary CT in a large proportion of patients. Observation and repeated TUS might be useful in unclear cases.
The Design of Carbon Fibre Composite Origami Airbrakes for Endeavour’s Darwin I Rocket
Authors: Lee Hyeon (Ann) , Alam Parvez
Published: June 2021

This paper concerns the conceptual design of a carbon fibre composite airbrake intended for use on the Endeavour Darwin I rocket. The airbrake design is based on a Flasher origami model and we research its actuation mechanism, its ability to increase drag, and its mechanical behaviour when actuated. The aim of this work was to improve upon the current ‘Pancake’ airbrake model and we find that the origami Flasher generates six times more drag at a given torque. The Flasher is designed to be built of quasi-isotropic CFRP resting on a carbon fibre woven membrane. When subjected to distributed loads from drag, the Flasher presses into the membrane material causing it to stress at levels of 1.4 GPa. Taking into account a safety factor of 1.2 for the rocket airbrake, this stress lies far below the failure stress of the carbon fibre woven membrane. In this work, the composite Flasher origami airbrake design offers improvements in drag and weight reduction, and will withstand drag forces when actuated.
An Axiom of True Courses Calculation in Great Circle Navigation
Authors: Baric Mate , Brčić David , Kosor Mate , Jelic Roko
Published: June 2021

Based on traditional expressions and spherical trigonometry, at present, great circle navigation is undertaken using various navigational software packages. Recent research has mainly focused on vector algebra. These problems are calculated numerically and are thus suited to computer-aided great circle navigation. However, essential knowledge requires the navigator to be able to calculate navigation parameters without the use of aids. This requirement is met using spherical trigonometry functions and the Napier wheel. In addition, to facilitate calculation, certain axioms have been developed to determine a vessel’s true course. These axioms can lead to misleading results due to the limitations of the trigonometric functions, mathematical errors, and the type of great circle navigation. The aim of this paper is to determine a reliable trigonometric function for calculating a vessel’s course in regular and composite great circle navigation, which can be used with the proposed axioms. This was achieved using analysis of the trigonometric functions, and assessment of their impact on the vessel’s calculated course and established axioms.
VPP Coupling High-Fidelity Analyses and Analytical Formulations for Multihulls Sails and Appendages Optimization
Authors: Cella Ubaldo , Salvadore Francesco , Ponzini Raffaele , Biancolini Marco Evangelos
Published: June 2021

A procedure for the optimization of a catamaran’s sail plan able to provide a preliminary optimal appendages configuration is described. The method integrates a sail parametric CAD model, an automatic computational domain generator and a Velocity Prediction Program (VPP) based on a combination of sail RANS computations and analytical models. The sailing speed and course angle are obtained, with an iterative process, solving the forces and moment equilibrium system of equations. Analytical formulations for the hull forces were developed and tuned against a matrix of CFD solutions. The appendages aerodynamic polars are estimated by applying preliminary design criteria from aerospace literature. The procedure permits us to find the combination of appendages configuration, rudders setting, sail planform, shape and trim that maximise the VMG (Velocity Made Good). Two versions of the sail analysis module were implemented: one adopting commercial software and one based on the use of only Open-Source codes. The solutions of the two modules were compared to evaluate advantages and limitations of the two approaches.
Reactor Core Conceptual Design for a Scalable Heating Experimental Reactor, LUTHER
Authors: Truong Thinh , Suikkanen Heikki , Hyvärinen Juhani
Published: June 2021

In this paper, the conceptual design and a preliminary study of the LUT Heating Experimental Reactor (LUTHER) for 2 MWth power are presented. Additionally, commercially sized designs for 24 MWth and 120 MWth powers are briefly discussed. LUTHER is a scalable light-water pressure-channel reactor designed to operate at low temperature, low pressure, and low core power density. The LUTHER core utilizes low enriched uranium (LEU) to produce low-temperature output, targeting the district heating demand in Finland. Nuclear power needs to contribute to the decarbonizing of the heating and cooling sector, which is a much more significant greenhouse gas emitter than electricity production in the Nordic countries. The main principle in the development of LUTHER is to simplify the core design and safety systems, which, along with using commercially available reactor components, would lead to lower fabrication costs and enhanced safety. LUTHER also features a unique design with movable individual fuel assembly for reactivity control and burnup compensation. Two-dimensional (2D) and three-dimensional (3D) fuel assemblies and reactor cores are modeled with the Serpent Monte Carlo reactor physics code. Different reactor design parameters and safety configurations are explored and assessed. The preliminary results show an optimal basic core design, a good neutronic performance, and the feasibility of controlling reactivity by moving fuel assemblies.
STRIPAK, a Key Regulator of Fungal Development, Operates as a Multifunctional Signaling Hub
Authors: Kück Ulrich , Stein Valentina
Published: June 2021

The striatin-interacting phosphatases and kinases (STRIPAK) multi subunit complex is a highly conserved signaling complex that controls diverse developmental processes in higher and lower eukaryotes. In this perspective article, we summarize how STRIPAK controls diverse developmental processes in euascomycetes, such as fruiting body formation, cell fusion, sexual and vegetative development, pathogenicity, symbiosis, as well as secondary metabolism. Recent structural investigations revealed information about the assembly and stoichiometry of the complex enabling it to act as a signaling hub. Multiple organellar targeting of STRIPAK subunits suggests how this complex connects several signaling transduction pathways involved in diverse cellular developmental processes. Furthermore, recent phosphoproteomic analysis shows that STRIPAK controls the dephosphorylation of subunits from several signaling complexes. We also refer to recent findings in yeast, where the STRIPAK homologue connects conserved signaling pathways, and based on this we suggest how so far non-characterized proteins may functions as receptors connecting mitophagy with the STRIPAK signaling complex. Such lines of investigation should contribute to the overall mechanistic understanding of how STRIPAK controls development in euascomycetes and beyond.
Knowledge—An Open Access Science and Technology Journal
Authors: Lin Shu-Kun
Published: June 2021

In 2021, the 12th volume of Information [...]
The Strength and Delamination of Graphene/Cu Composites with Different Cu Thicknesses
Authors: Kim Song-Mi , Park Woo-Rim , Kwon Oh-Heon
Published: June 2021

This study analyzed the mechanical and fracture behavior of graphene/copper (Cu) composites with different Cu thicknesses by using molecular dynamics (MD) and representative volume element (RVE) analysis. Three graphene/Cu composite analytical models were classified as 4.8, 9.8, and 14.3 nm according to Cu thicknesses. Using MD analysis, zigzag-, armchair-, and z (thickness)-direction tensile analyses were performed for each model to analyze the effect of Cu thickness variation on graphene/Cu composite strength and delamination fracture. In the RVE analysis, the mechanical characteristics of the interface between graphene and Cu were evaluated by setting the volume fraction to 1.39, 2.04, and 4.16% of the graphene/Cu composite model, classified according to the Cu thickness. From their obtained results, whether the graphene bond is maintained has the greatest effect on the strength of graphene/Cu composites, regardless of the Cu thickness. Additionally, graphene/Cu composites are more vulnerable to armchair direction tensile forces with fracture strengths of 14.7, 8.9, and 8.2 GPa depending on the Cu thickness. The results of this study will contribute to the development of guidelines and performance evaluation standards for graphene/Cu composites.
Naturally Formed Chitinous Skeleton Isolated from the Marine Demosponge Aplysina fistularis as a 3D Scaffold for Tissue Engineering
Authors: Machałowski Tomasz , Rusak Agnieszka , Wiatrak Benita , Haczkiewicz-Leśniak Katarzyna , Popiel Aneta , Jaroszewicz Jakub , Żak Andrzej , Podhorska-Okołów Marzenna , Jesionowski Teofil
Published: June 2021

Tissue engineering (TE) is a field of regenerative medicine that has been experiencing a special boom in recent years. Among various materials used as components of 3D scaffolds, naturally formed chitinous materials seem to be especially attractive because of their abundance, non-toxic and eco-friendly character. In this study, chitinous skeleton isolated from the marine sponge Aplysina fistularis (phylum: Porifera) was used for the first time as a support for the cultivation of murine fibroblasts (Balb/3T3), human dermal fibroblasts (NHDF), human keratinocyte (HaCaT), and human neuronal (SH-SY5Y) cells. Characterization techniques such as ATR FTIR, TGA, and μCT, clearly indicate that an interconnected macro-porous, thermostable, pure α-chitin scaffold was obtained after alkali–acid treatment of air-dried marine sponge. The biocompatibility of the naturally formed chitin scaffolds was confirmed by cell attachment and proliferation determined by various microscopic methods (e.g., SEM, TEM, digital microscopy) and specific staining. Our observations show that fibroblasts and keratinocytes form clusters on scaffolds that resemble a skin structure, including the occurrence of desmosomes in keratinocyte cells. The results obtained here suggest that the chitinous scaffold from the marine sponge A. fistularis is a promising biomaterial for future research about tissues regeneration.
Effect of Powder Heat Treatment on Chemical Composition and Thermoelectric Properties of Bismuth Antimony Telluride Alloys Fabricated by Combining Water Atomization and Spark Plasma Sintering
Authors: Shin Dong-won , Dharmaiah Peyala , Song Jun-Woo , Hong Soon-Jik
Published: June 2021

In this work, Bi0.5Sb1.5Te3 materials were produced by an economically viable and time efficient water atomization process. The powder samples were heat treated at different temperatures (673 K, 723 K, 743 K, 773 K, 803 K, and 823 K) followed by spark plasma sintering (SPS). It was found that the Te evaporated slightly at 723 K and 743 K and became dominated at 773 K, 803 K, and 823 K, which severely influences the thermoelectric properties. The electrical conductivity was significantly improved for over 803 K heat treated samples due to the remarkable improvement in hole concentration. The power factor values for the 803 K and 823 K samples were significantly larger at T > 350 K compared to other samples. Consequently, the peak ZT of 0.92 at 350 K was obtained for the 803 K sample, which could be useful in commercial thermoelectric power generation.
Bubble Swelling in Ferritic/Martensitic Steels Exposed to Radiation Environment with High Production Rate of Helium
Authors: Sojak Stanislav , Degmova Jarmila , Noga Pavol , Krsjak Vladimir , Slugen Vladimir , Shen Tielong
Published: June 2021

Reduced-activativon ferritic/martensitic (RAFM) steels are prospective structural materials for fission/fusion nuclear applications because their radiation and swelling resistance outperforms their austenitic counterparts. In radiation environments with a high production rate of helium, such as fusion or spallation applications, these materials suffer from non-negligible swelling due to the inhibited recombination between vacancy and interstitial-type defects. In this work, swelling in helium-implanted Eurofer 97 steel is investigated with a focus on helium production rates in a wide range of helium/dpa ratios. The results show virtually no swelling incubation period preceding a steady-state swelling of about 2 × 10−4%/He-appm/dpa. A saturation of swelling above 5000 He-appm/dpa was observed and attributed to helium bubbles becoming the dominant sinks for new vacancies and helium atoms. Despite a relatively low irradiation temperature (65 ± 5 °C) and a rather high concentration of helium, transmission electron microscope (TEM) results confirmed a microstructure typical of ferritic/martensitic steels exposed to radiation environments with high production rates of helium.
Influence of Thermal Annealing on the Sinterability of Different Grades of Polylactide Microspheres Dedicated for Laser Sintering
Authors: Gazińska Małgorzata , Krokos Anna , Kryszak Bartłomiej , Dzienny Paulina , Olejarczyk Michał , Gruber Piotr , Kwiatkowski Ryszard , Antończak Arkadiusz
Published: June 2021

We present a comparison of the influence of the conditioning temperature of microspheres made of medical grade poly(L-lactide) (PLLA) and polylactide with 4 wt % of D-lactide content (PLA) on the thermal and structural properties. The microspheres were fabricated using the solid-in-oil-in-water method for applications in additive manufacturing. The microspheres were annealed below the glass transition temperature (Tg), above Tg but below the onset of cold crystallization, and at two temperatures selected from the range of cold crystallization corresponding to the crystallization of the α’ and α form of poly(L-lactide), i.e., at 40, 70, 90, and 120 °C, in order to verify the influence of the conditioning temperature on the sinterability of the microspheres set as the sintering window (SW). Based on differential scanning calorimetry measurements, the SWs of the microspheres were evaluated with consideration of the existence of cold crystallization and reorganization of crystal polymorphs. The results indicated that the conditioning temperature influenced the availability and range of the SWs depending on the D-lactide presence. We postulate the need for an individual approach for polylactide powders in determining the SW as a temperature range free of any thermal events. We also characterized other core powder characteristics, such as the residual solvent content, morphology, particle size distribution, powder flowability, and thermal conductivity, as key properties for successful laser sintering. The microspheres were close to spheres, and the size of the microspheres was below 100 µm. The residual solvent content decreased with the increase of the annealing temperature. The thermal conductivities were 0.073 and 0.064 W/mK for PLA and PLLA microspheres, respectively, and this depended on the spherical shape of the microspheres. The wide angle X-ray diffraction (WAXD) studies proved that an increase in the conditioning temperature caused a slight increase in the crystallinity degree for PLLA microspheres and a clear increase in crystallization for the PLA microspheres.
Development of a Backward–Forward Stochastic Particle Tracking Model for Identification of Probable Sedimentation Sources in Open Channel Flow
Authors: Liu Chelsie Chia-Hsin , Tsai Christina W. , Huang Yu-Ying
Published: June 2021

As reservoirs subject to sedimentation, the dam gradually loses its ability to store water. The identification of the sources of deposited sediments is an effective and efficient means of tackling sedimentation problems. A state-of-the-art Lagrangian stochastic particle tracking model with backward–forward tracking methods is applied to identify the probable source regions of deposited sediments. An influence function is introduced into the models to represent the influence of a particular upstream area on the sediment deposition area. One can then verify if a specific area might be a probable source by cross-checking the values of influence functions calculated backward and forward, respectively. In these models, the probable sources of the deposited sediments are considered to be in a grid instead of at a point for derivation of the values of influence functions. The sediment concentrations in upstream regions must be known a priori to determine the influence functions. In addition, the accuracy of the different types of diffusivity at the water surface is discussed in the study. According to the results of the case study of source identification, the regions with higher sediment concentrations computed by only backward simulations do not necessarily imply a higher likelihood of sources. It is also shown that from the ensemble results when the ensemble mean of the concentration is higher, the ensemble standard deviation of the concentration is also increased.
On a Generalization of One-Dimensional Kinetics
Authors: Uchaikin Vladimir V. , Sibatov Renat T. , Bezbatko Dmitry N.
Published: June 2021

One-dimensional random walks with a constant velocity between scattering are considered. The exact solution is expressed in terms of multiple convolutions of path-distributions assumed to be different for positive and negative directions of the walk axis. Several special cases are considered when the convolutions are expressed in explicit form. As a particular case, the solution of A. S. Monin for a symmetric random walk with exponential path distribution and its generalization to the asymmetric case are obtained. Solution of fractional telegraph equation with the fractional material derivative is presented. Asymptotic behavior of its solution for an asymmetric case is provided.
Estimation of the Optimal Threshold Policy in a Queue with Heterogeneous Servers Using a Heuristic Solution and Artificial Neural Networks
Authors: Efrosinin Dmitry , Stepanova Natalia
Published: June 2021

This paper deals with heterogeneous queues where servers differ not only in service rates but also in operating costs. The classical optimisation problem in queueing systems with heterogeneous servers consists in the optimal allocation of customers between the servers with the aim to minimise the long-run average costs of the system per unit of time. As it is known, under some assumptions the optimal allocation policy for this system is of threshold type, i.e., the policy depends on the queue length and the state of faster servers. The optimal thresholds can be calculated using a Markov decision process by implementing the policy-iteration algorithm. This algorithm may have certain limitations on obtaining a result for the entire range of system parameter values. However, the available data sets for evaluated optimal threshold levels and values of system parameters can be used to provide estimations for optimal thresholds through artificial neural networks. The obtained results are accompanied by a simple heuristic solution. Numerical examples illustrate the quality of estimations.
Orbit Growth of Shift Spaces Induced by Bouquet Graphs and Dyck Shifts
Authors: Nordin Azmeer , Noorani Mohd Salmi Md
Published: June 2021

For a discrete dynamical system, the prime orbit and Mertens’ orbit counting functions describe the growth of its closed orbits in a certain way. The asymptotic behaviours of these counting functions can be determined via Artin–Mazur zeta function of the system. Specifically, the existence of a non-vanishing meromorphic extension of the zeta function leads to certain asymptotic results. In this paper, we prove the asymptotic behaviours of the counting functions for a certain type of shift spaces induced by directed bouquet graphs and Dyck shifts. We call these shift spaces as the bouquet-Dyck shifts. Since their respective zeta function involves square roots of polynomials, the meromorphic extension is difficult to be obtained. To overcome this obstacle, we employ some theories on zeros of polynomials, including the well-known Eneström–Kakeya Theorem in complex analysis. Finally, the meromorphic extension will imply the desired asymptotic results.
Integer Codes Correcting Asymmetric Errors in Nand Flash Memory
Authors: Kostadinov Hristo , Manev Nikolai
Published: June 2021

Memory devices based on floating-gate transistor have recently become dominant technology for non-volatile storage devices like USB flash drives, memory cards, solid-state disks, etc. In contrast to many communication channels, the errors observed in flash memory device use are not random but of special, mainly asymmetric, type. Integer codes which have proved their efficiency in many cases with asymmetric errors can be applied successfully to flash memory devices, too. This paper presents a new construction and integer codes over a ring of integers modulo A=2n+1 capable of correcting single errors of type (1,2),(±1,±2), or (1,2,3) that are typical for flash memory devices. The construction is based on the use of cyclotomic cosets of 2 modulo A. The parity-check matrices of the codes are listed for n≤10.
Collaborative Service Innovation: A Quantitative Analysis of Innovation Networks in a Multisectoral Setting
Authors: Peralta Alberto , Rubalcaba Luis
Published: June 2021

Partial least squares structural equation modelling has proven very valuable to study the unexplored and complex public service innovation networks (PSINs) in the public sector, from a socio-economic stance. Web have modelled PSINs’ three structural variables—Social, Actors, and Functioning mode—using a sample of original data (n = 233). Our PSINs’ model confirms them as instruments that produce public service innovation—involving technological and nontechnological characteristics. Additionally, we set-up a novel and potentially fruitful methodology to study the intricate formation and impact of complex socio-economical structures that connect innovation and public services. Hence, our research supports a better and extended use of PSINs as a tool for policy and service co-design and co-implementation. And we open a promising line of studies involving multi-actor collaboration in the public sector.
Reinstatement of the Extension Principle in Approaching Mathematical Programming with Fuzzy Numbers
Authors: Stanojević Bogdana , Stanojević Milan , Nădăban Sorin
Published: June 2021

Optimization problems in the fuzzy environment are widely studied in the literature. We restrict our attention to mathematical programming problems with coefficients and/or decision variables expressed by fuzzy numbers. Since the review of the recent literature on mathematical programming in the fuzzy environment shows that the extension principle is widely present through the fuzzy arithmetic but much less involved in the foundations of the solution concepts, we believe that efforts to rehabilitate the idea of following the extension principle when deriving relevant fuzzy descriptions to optimal solutions are highly needed. This paper identifies the current position and role of the extension principle in solving mathematical programming problems that involve fuzzy numbers in their models, highlighting the indispensability of the extension principle in approaching this class of problems. After presenting the basic ideas in fuzzy optimization, underlying the advantages and disadvantages of different solution approaches, we review the main methodologies yielding solutions that elude the extension principle, and then compare them to those that follow it. We also suggest research directions focusing on using the extension principle in all stages of the optimization process.
The Bateman Functions Revisited after 90 Years—A Survey of Old and New Results
Authors: Apelblat Alexander , Consiglio Armando , Mainardi Francesco
Published: June 2021

The Bateman functions and the allied Havelock functions were introduced as solutions of some problems in hydrodynamics about ninety years ago, but after a period of one or two decades they were practically neglected. In handbooks, the Bateman function is only mentioned as a particular case of the confluent hypergeometric function. In order to revive our knowledge on these functions, their basic properties (recurrence functional and differential relations, series, integrals and the Laplace transforms) are presented. Some new results are also included. Special attention is directed to the Bateman and Havelock functions with integer orders, to generalizations of these functions and to the Bateman-integral function known in the literature.
Nonlinear Mixed Convective Flow over a Moving Yawed Cylinder Driven by Buoyancy
Authors: Patil Prabhugouda M. , Shankar Hadapad F. , Sheremet Mikhail A.
Published: June 2021

The fluid flow over a yawed cylinder is useful in understanding practical significance for undersea applications, for example, managing transference and/or separation of the boundary layer above submerged blocks and in suppressing recirculating bubbles. The present analysis examines nonlinear mixed convection flow past a moving yawed cylinder with diffusion of liquid hydrogen. The coupled nonlinear control relations and the border restrictions pertinent to the present flow problem are nondimensionalized by using nonsimilar reduction. Further, implicit finite difference schemes and Quasilinearization methods are employed to solve the nondimensional governing equations. Impact of several nondimensional parameters of the analysis on the dimensionless velocity, temperature and species concentration patterns and also on Nusselt number, Sherwood number and friction parameter defined at the cylinder shell is analyzed through numerical results presented in various graphs. Velocity profiles can be enhanced, and the coefficients of friction at the surface can be reduced, for increasing values of velocity ratio parameters along chordwise as well as spanwise directions. Species concentration profile is reduced, while the Sherwood number is enhanced, for growth of the Schmidt number and yaw angles. Furthermore, for an increasing value of yaw angle, skin-friction coefficient in chordwise direction diminishes in opposing buoyancy flow case, whereas the results exhibit the opposite trend in assisting buoyancy flow case. Moreover, very importantly, for increasing magnitude of nonlinear convection characteristic, the liquid velocity and surface friction enhance in spanwise direction. Further, for increasing magnitude of combined convection characteristics, velocity profiles and coefficient of friction at the surface enhance in both spanwise and chordwise directions. Moreover, we have observed that there is no deviation for zero yaw angle in Nusselt number and Sherwood number.
May We Use Non-Invasive Indices of Aortic Stiffness and Endothelial Glycocalyx as Biomarkers for Idiopathic Pulmonary Artery Hypertension Follow-Up?
Authors: Triantafyllidi Helen , Birmpa Dionysia , Benas Dimitrios , Ikonomidis Ignatios , Schoinas Antonis , Trivilou Paraskevi , Frantzeskaki Frantzeska , Orfanos Stylianos E.
Published: June 2021

Idiopathic pulmonary arterial hypertension (IPAH) initial evaluation and follow-up, a rare and incurable disease if left untreated, is based on a multiparametric approach (functional status of the patient, biomarkers, hemodynamic parameters and imaging evaluation of right heart impairment). Arterial stiffness (AS) and endothelial glycocalyx are indices of systemic circulation. We present the 3-years follow-up of a female IPAH patient. We propose aortic stiffness and endothelial glycocalyx indices as non-invasive markers of either improvement or deterioration of IPAH disease.
To Enhance or Not to Enhance? The Role of Contrast Medium 18F-FDG PET/CT in Recurrent Ovarian Carcinomas
Authors: Massollo Michela , Fiz Francesco , Bottoni Gianluca , Ugolini Martina , Paparo Francesco , Puppo Cristina , Provinciali Nicoletta , Iacozzi Massimiliano , Altrinetti Vania , Cistaro Angelina , Cabria Manlio , DeCensi Andrea , Treglia Giorgio , Piccardo Arnoldo
Published: June 2021

Background and Objectives: 18F-fluorodeoxyglucose (FDG) positron emission tomography/X-ray computed tomography (PET/CT) represents the mainstay diagnostic procedure for suspected ovarian cancer (OC) recurrence. PET/CT can be integrated with contrast medium and in various diagnostic settings; however, the effective benefit of this procedure is still debated. We aimed to compare the diagnostic capabilities of low-dose and contrast-enhanced PET/CT (PET/ldCT and PET/ceCT) in patients with suspected ovarian cancer relapse. Materials and Methods: 122 OC patients underwent both PET/ldCT and PET/ceCT. Two groups of nuclear medicine physicians and radiologists scored the findings as positive or negative. Clinical/radiological follow-up was used as ground truth. Sensitivity, specificity, negative/positive predictive value, and accuracy were calculated at the patient and the lesion level. Results: A total of 455 and 474 lesions were identified at PET/ldCT and PET/ceCT, respectively. At the lesion level, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were not significantly different between PET/ldCT and PET/ceCT (98%, 93.3%, 97.4%, 94.9%, and 96.9% for PET/ldCT; 99%, 95.5%, 98.3%, 97%, and 98% for PET/ceCT, p = ns). At the patient level, no significant differences in these parameters were identified (e.g., p = 0.22 and p = 0.35 for accuracy, in the peritoneum and lymph nodes, respectively). Smaller peritoneal/lymph node lesions close to physiological FDG uptake sources were found in the cases of misidentification by PET/ldCT. PET/ceCT prompted a change in clinical management in four cases (3.2%) compared to PET/ldCT. Conclusions: PET/ceCT does not perform better than PET/ldCT but can occasionally clarify doubtful peritoneal findings on PET/ldCT. To avoid unnecessary dose to the patient, PET/ceCT should be excluded in selected cases.
Anticorrosion Performance of PVDF Membranes Modified by Blending PTFE Nanoemulsion and Prepared through Usual Non-Solvent-Induced Phase Inversion Method
Authors: Liu Tianshu , Zhou Xiaoji , Sun Yizhuo , Bai Renbi
Published: June 2021

In this study, PVDF/PTFE composite membranes were prepared by adding a PTFE nanoemulsion to a PVDF solution and casting it through the conventional non-solvent-induced phase separation method. The objective was to explore the effectiveness of using a simple and economical method to modify PVDF membranes with PTFE to enhance their anticorrosion performance, especially under highly acidic or alkaline conditions. PTFE nanoparticles (of around 200 nm in size) in nanoemulsion form were blended with PVDF at a mass ratio of PTFE:PVDF in the range of 0–0.3:1. The obtained membranes were examined to determine the effect of the added PTFE nanoparticles on the structure of the modified PVDF membranes as well as on their mechanical strength and surface characteristics. The membranes were then immersed in various concentrations of acidic or alkaline solutions for varied durations ranging from a few days up to as long as 180 days (6 months). The impacts of by the corrosive solutions on the tensile strength, surface roughness, and water flux of the membranes with different exposure times were quantified. The results showed that although a certain extent of change may occur with extended immersion times, greatly enhanced anticorrosion performance was obtained with the prepared PVDF/PTFE membranes compared with the unmodified PVDF membrane. For example, after being immersed in 5 mol-H+··L−1 H2SO4, HCl, and HNO3 solutions for 6 months, the tensile strength at breaking point remained at up to 69.70, 74.07, and 71.38%, respectively, of the initial strength for the PVDF/PTFE (M30) membrane. This was in contrast to values of only 55.77, 70.43, and 61.78% for the unmodified PVDF membrane (M0). Although the water flux and surface roughness showed a change trends to the tensile strength, the PVDF/PTFE (M30) membrane had much higher stability than the PVDF (M0) membrane. In a continuous filtration experiment containing H2SO4 at 0.01 mol-H+·L−1 for 336 h (14 days), the PVDF/PTFE membrane showed a maximum flux change of less than 30%. This was in comparison with a change of up to 50% for the PVDF membrane. However, the PVDF/PTFE membranes did not seem to have a greatly enhanced anticorrosion performance in the alkaline solution environment tested.
Electrophoretic Deposition of a Hybrid Graphene Oxide/Biomolecule Coating Facilitating Controllable Drug Loading and Release
Authors: Oh Jun-Sung , Jang Jun-Hwee , Lee Eun-Jung
Published: June 2021

Two-dimensional (2D) graphene oxide (GO) exhibits a high drug loading capacity per unit mass due to its unique structure and hydrophilicity and has been widely researched for drug-delivery systems. Here, we modified the surfaces of metal implants; we applied GO-based coatings that controlled drug loading and release. We used electrophoretic deposition (EPD) to apply the coatings at room temperature. The EPD coatings were analyzed in terms of their components, physical properties such as hardness and hydrophilicity, and in vitro cell tests of their biological properties. Uniform GO-EPD coatings improved surface hydrophilicity and hardness and greatly improved the bone differentiation properties of the metal substrate. Drug loading and release increased greatly compared to when the drug was adsorbed to only the surface of a coating. GO facilitated deposition of a drug-containing coating via EPD, and the surface modification, and drug loading and release, were controlled by the thickness of the coating.
Effects of Hyperhomocysteinemia on the Platelet-Driven Contraction of Blood Clots
Authors: Litvinov Rustem I. , Peshkova Alina D. , Le Minh Giang , Khaertdinov Nail N. , Evtugina Natalia G. , Sitdikova Guzel F. , Weisel John W.
Published: June 2021

Hyperhomocysteinemia (HHcy) is associated with thrombosis, but the mechanistic links between them are not understood. We studied effects of homocysteine (Hcy) on clot contraction in vitro and in a rat model of HHcy. Incubation of blood with exogenous Hcy for 1 min enhanced clot contraction, while 15-min incubation led to a dose-dependent suppression of contraction. These effects were likely due to direct Hcy-induced platelet activation followed by exhaustion, as revealed by an increase in fibrinogen-binding capacity and P-selectin expression determined by flow cytometry. In the blood of rats with HHcy, clot contraction was enhanced at moderately elevated Hcy levels (10–50 μM), while at higher Hcy levels (>50 μM), the onset of clot contraction was delayed. HHcy was associated with thrombocytosis combined with a reduced erythrocyte count and hypofibrinogenemia. These data suggest that in HHcy, platelets get activated directly and indirectly, leading to enhanced clot contraction that is facilitated by the reduced content and resilience of fibrin and erythrocytes in the clot. The excessive platelet activation can lead to exhaustion and impaired contractility, which makes clots larger and more obstructive. In conclusion, HHcy modulates blood clot contraction, which may comprise an underappreciated pro- or antithrombotic mechanism.
Fabrication of a Robust In2O3 Nanolines FET Device as a Biosensor Platform
Authors: Zhu Zetao , Yasui Takao , Liu Quanli , Nagashima Kazuki , Takahashi Tsunaki , Shimada Taisuke , Yanagida Takeshi , Baba Yoshinobu
Published: June 2021

Field-effect transistors (FETs) are attractive biosensor platforms for rapid and accurate detection of various analytes through surface immobilization of specific bio-receptors. Since it is difficult to maintain the electrical stability of semiconductors of sensing channel under physiological conditions for long periods, passivation by a stable metal oxide dielectric layer, such as Al2O3 or HfO2, is currently used as a common method to prevent damage. However, protecting the sensing channel by passivation has the disadvantage that the distance between the target and the conductive channel increases, and the sensing signal will be degraded by Debye shielding. Even though many efforts use semiconductor materials directly as channels for biosensors, the electrical stability of semiconductors in the physiological environments has rarely been studied. In this work, an In2O3 nanolines FET device with high robustness in artificial physiological solution of phosphate buffered saline (PBS) was fabricated and used as a platform for biosensors without employing passivation on the sensing channel. The FET device demonstrated reproducibility with an average threshold voltage (VTH) of 5.235 V and a standard deviation (SD) of 0.382 V. We tested the robustness of the In2O3 nanolines FET device in PBS solution and found that the device had a long-term electrical stability in PBS with more than 9 days’ exposure. Finally, we demonstrated its applicability as a biosensor platform by testing the biosensing performance towards miR-21 targets after immobilizing the phosphonic acid terminated DNA probes. Since the surface immobilization of multiple bioreceptors is feasible, we demonstrate that the robust In2O3 FET device can be an excellent biosensor platform for biosensors.
Hysteresis in As-Synthesized MoS2 Transistors: Origin and Sensing Perspectives
Authors: Marquez Carlos , Salazar Norberto , Gity Farzan , Galdon Jose C. , Navarro Carlos , Sampedro Carlos , Hurley Paul K. , Chang Edward Yi , Gamiz Francisco
Published: June 2021

Two-dimensional materials, including molybdenum disulfide (MoS2), present promising sensing and detecting capabilities thanks to their extreme sensitivity to changes in the environment. Their reduced thickness also facilitates the electrostatic control of the channel and opens the door to flexible electronic applications. However, these materials still exhibit integration difficulties with complementary-MOS standardized processes and methods. The device reliability is compromised by gate insulator selection and the quality of the metal/semiconductor and semiconductor/insulator interfaces. Despite some improvements regarding mobility, hysteresis and Schottky barriers having been reported thanks to metal engineering, vertically stacked heterostructures with compatible thin-layers (such as hexagonal boron nitride or device encapsulation) variability is still an important constraint to sensor performance. In this work, we fabricated and extensively characterized the reliability of as-synthesized back-gated MoS2 transistors. Under atmospheric and room-temperature conditions, these devices present a wide electrical hysteresis (up to 5 volts) in their transfer characteristics. However, their performance is highly influenced by the temperature, light and pressure conditions. The singular signature in the time response of the devices points to adsorbates and contaminants inducing mobile charges and trapping/detrapping carrier phenomena as the mechanisms responsible for time-dependent current degradation. Far from being only a reliability issue, we demonstrated a method to exploit this device response to perform light, temperature and/or pressure sensors in as-synthesized devices. Two orders of magnitude drain current level differences were demonstrated by comparing device operation under light and dark conditions while a factor up to 105 is observed at vacuum versus atmospheric pressure environments.
Microwave Imaging of Breast Skin Utilizing Elliptical UWB Antenna and Reverse Problems Algorithm
Authors: Alani Sameer , Zakaria Zahriladha , Saeidi Tale , Ahmad Asmala , Imran Muhammad Ali , Abbasi Qammer H.
Published: June 2021

Skin cancer is one of the most widespread and fast growing of all kinds of cancer since it affects the human body easily due to exposure to the Sun’s rays. Microwave imaging has shown better outcomes with higher resolution, faster processing time, mobility, and less cutter and artifact effects. A miniaturized elliptical ultra-wideband (UWB) antenna and its semi-spherical array arrangement were used for signal transmission and reception from the defected locations in the breast skin. Several conditions such as various arrays of three, six, and nine antenna elements, smaller tumor, multi-tumors, and skin on a larger breast sample of 30 cm were considered. To assess the ability of the system, a breast shape container with a diameter of 130 mm and height of 60 mm was 3D printed and then filled with fabricated skin and breast fat to perform the experimental investigation. An improved modified time-reversal algorithm (IMTR) was used to recreate 2D images of tumors with the smallest radius of 1.75 mm in any location within the breast skin. The reconstructed images using both simulated and experimental data verified that the system can be a reliable imaging system for skin cancer diagnosis having a high structural similarity index and resolution.
Targeted Molecular Detection of Nosocomial Carbapenemase-Producing Gram-Negative Bacteria—On Near- and Distant-Patient Surfaces
Authors: Stein Claudia , Lange Isabel , Rödel Jürgen , Pletz Mathias W. , Kipp Frank
Published: June 2021

Background: Here, we describe an integrative method to detect carbapenemase-producing Gram-negative bacteria (gn-Cp) on surfaces/fomites in the patient environment. We examined environmental samples from 28 patient rooms occupied with patients who were proven to be colonised with gn-Cp by rectal screening. Methods: We took samples after 24 h, 72 h and one week. For sampling, we divided the patient environment into four parts and took samples from near- and extended patient areas. To obtain a representative bacterial swab from a larger surface, such as the patient cabinet, we used Polywipes. Bacterial DNA was isolated. Carbapenemase was detected with specific qPCR primers. Results: With this culture- and molecular-based approach, we could control the effectiveness of cleaning and disinfection in everyday clinical practice. Therefore, we could track the spread of gn-Cp within the patient room. The number of positive detections fluctuated between 30.5% (mean value positive results after 72 h) and 35.2% (after 24 h and one week). Conclusion: The method used to detect multidrug-resistant bacteria in the environment of patients by using PolywipesTM is reliable and can therefore be used as an effective, new tool in hygiene and infection control.