bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation on GaN-Based Membrane Photonic Crystal Surface Emitting Lasers
Authors: Bin Jingtong , Feng Kerui , Shen Wei , Meng Minjia , Liu Qifa
Published: February 2022

A GaN-based blue photonic crystal surface emitting laser (PCSEL) featured with membrane configuration was proposed and theoretically investigated. The membrane dimension, photonic crystal (PhC) material, lattice constant and thickness were studied by RCWA (Rigorous Coupled Wave Analysis), FDTD (Finite Difference Time Domain) simulations with the confinement factor and gain threshold as indicators. The membrane PCSEL’s confinement factor of active media is of 13~14% which is attributed to multi-pairs of quantum wells and efficient confinement of the mode in the membrane cavity with air claddings. The excellent confinement factor and larger Q factor of resonance mutually contribute to the lower gain threshold of the design (below 400 cm−1 for GaN-PhC with 100 nm thick top and bottom GaN layer, 40 nm hole radius and 40 nm depth). The PhC confinement factor exceeds 13% and 6% for TiO2-PhC with 80 nm and 60 nm PhC thickness and 20 nm and 40 nm distance between PhC and active media, respectively. It is around two times larger than that of GaN-PhC, which is attributed to the higher refractive index of TiO2 that pulls field distribution to the PhC layer.
An Artificial PVA-BC Composite That Mimics the Biomechanical Properties and Structure of a Natural Intervertebral Disc
Authors: Yang Mengying , Xiang Dingding , Chen Yuru , Cui Yangyang , Wang Song , Liu Weiqiang
Published: February 2022

Disc herniation is one of the most ubiquitous healthcare problems in modern cities—severe patients eventually require surgical intervention. However, the existing operations—spinal fusion and artificial disc replacement—alter the biomechanics of the spine, leaving much room for improvement. The appropriateness of polyvinyl alcohol (PVA) for biomedical applications has been recognised due to its high water content, excellent biocompatibility, and versatile mechanical properties. In this study, a newly-designed PVA–bacterial cellulose (PVA-BC) composite was assembled to mimic both the biomechanics and annular structure of natural intervertebral discs (IVDs). PVA-BC composites of various concentrations were fabricated and tested under unconfined compression and compressive creep in order to acquire the values of the normalised compressive stiffness and whole normalised deformation. The normalised compressive stiffness increased considerably with an increasing PVA concentration, spanning from 1.82 (±0.18) to 3.50 (±0.14) MPa, and the whole normalised deformation decreased from 0.25 to 0.13. Formulations of 40% PVA provided the most accurate mimicry of natural human IVDs in normalised whole deformation, and demonstrated higher dimensional stability. The biocompatible results further confirmed that the materials had excellent biocompatibility. The novel bionic structure and formulations of the PVA-BC materials mimicked the biomechanics and structure of natural IVDs, and ensured dimensional stability under prolonged compression, reducing the risk of impingement on the surrounding tissue. The PVA-BC composite is a promising material for third-generation artificial IVDs with integrated construction.
Experimental Study on Microstructure and Erosion Mechanisms of Solid Waste Cemented Paste Backfill under the Combined Action of Dry–Wet Cycles and Sulphate Erosion
Authors: Li Kexin , Li Xilin , Du Chuanyang , Xue Haowen , Sun Qi , Liu Ling
Published: February 2022

Solid waste cemented paste backfill (SWCPB) meets the needs of coal mining area management. SWCPB is a cementitious paste backfill material without added cement and is made only from oil shale residue (OSR), steel slag (SS), soda residue (SR) and water. In this study, mine water characteristics were simulated by combining dry–wet cycling experiments with sulphate erosion experiments. SWCPB was assessed regarding appearance, mass loss, and unconfined compressive strength (UCS), and the erosion products were microscopically analysed with X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The mechanism for erosion of the SWCPB by sulphate-rich mine water was comprehensively analysed and revealed. Research showed that the erosion mechanism was divided into two parts: chemical and physical erosion. Low concentrations of sodium sulphate promoted hydration, thereby contributing to the increased mass and strength of SWCPB. At high sodium sulphate concentrations, the erosion mainly consumed Ca(OH)2 within the material, and the main generated erosion products were gypsum and ettringite (AFt). This was accompanied by the destructive effects of Na2SO4 crystal expansion, which resulted in damage and the reduced workability of the SWCPB. The whole erosion process was continuous, mainly due to transformations of pits, pores and cracks. The conclusions of this study may provide appropriate guidance for application of SWCPB materials in the treatment of coal mine backfills. In addition, the corresponding theoretical analysis of the erosion mechanism for SWCPB materials is provided.
A Comparative Study on the Shear Behavior of UHPC Beams with Macro Hooked-End Steel Fibers and PVA Fibers
Authors: Bermudez Manuel , Wen Kuo-Wei , Hung Chung-Chan
Published: February 2022

Structural members made of ultra-high-performance concrete (UHPC) have been attractive to engineers and researchers due to their superior mechanical properties and durability. However, existing studies were focused on the behavior of UHPC members reinforced with micro straight steel fibers at a volume fraction between 1 and 3%. There is a lack of studies on the influence of different types and amounts of fibers on the shear behavior of UHPC structural members. The objective of the study was to experimentally investigate the shear behavior of UHPC beams with macro hooked-end steel (MHS) fibers and polyvinyl alcohol (PVA) fibers, which are two of the most used fibers for high-performance fiber-reinforced cementitious composites. The shear behavior of ten large-scale non-prestressed UHPC beams was studied. The experimental parameters included the shear span-to-effective depth ratio, the fiber volume fraction, and the type of fibers. It was found that both MHS fibers and PVA fibers were effective in enhancing the shear performance of the UHPC beams whether the shear transfer mechanism was governed by arch action or beam action. Moreover, the measurement results of the average crack spacing imply the distinct difference in the fiber bridging effects of the MHS fibers and PVA fibers in the UHPC beams.
Microstructure and Corrosion Behavior of Atmospheric Plasma Sprayed NiCoCrAlFe High Entropy Alloy Coating
Authors: Mehmood Kashif , Umer Malik Adeel , Munawar Ahmed Umar , Imran Muhammad , Shahid Muhammad , Ilyas Muhammad , Firdous Rabeeka , Kousar Humaira , Usman Muhammad
Published: February 2022

High entropy alloys (HEAs) are multi-elemental alloy systems that exhibit a combination of exceptional mechanical and physical properties, and nowadays are validating their potential in the form of thermal sprayed coatings. In the present study, a novel synthesis method is presented to form high entropy alloy coatings. For this purpose, thermal sprayed coatings were deposited on Stainless Steel 316L substrates using atmospheric plasma spraying technique with subsequent annealing, at 1000 °C for 4 h, to assist alloy formation by thermal diffusion. The coatings in as-coated samples as well as in annealed forms were extensively studied by SEM for microstructure and cross-sectional analysis. Phase identification was performed by X-ray diffraction studies. The annealed coatings revealed a mixed BCC and FCC based HEA structure. Potentiodynamic corrosion behavior of SS316L sprayed as well as annealed coatings were also carried out in 3.5% NaCl solution and it was found that the HEA-based annealed coatings displayed the best corrosion resistance 0.83 (mpy), as compared to coated/non-annealed and SS 316 L that showed corrosion resistance of 7.60 (mpy) and 3.04 (mpy), respectively.
Stability Analysis of Vaneless Space in High-Head Pump-Turbine under Turbine Mode: Computational Fluid Dynamics Simulation and Particle Imaging Velocimetry Measurement
Authors: Deng Wanquan , Xu Lianchen , Li Zhen , Tang Wen , Wang Xiaolong , Shang Linmin , Liu Demin , Liu Xiaobing
Published: February 2022

When the Francis-type reversible pump-turbine runs under partial load, the pressure pulsation amplitude and frequency in vaneless space are high, posing a serious threat to the stability of unit operation. Water presents weak compressibility in a high-head pump-turbine, thereby affecting the amplitude–frequency characteristics of pressure pulsation. This study used numerical simulations in a model and prototype pump-turbine and particle image velocimetry (PIV) in a model pump-turbine to examine the internal flow field and pressure pulsation characteristics and determine the effect of the flow in the vaneless space on the amplitude–frequency characteristics of the pressure pulsation. The pressure pulsation amplitude–frequency characteristics were verified through prototype tests. The effects of the weak compressibility of the water on the propagation law of pressure pulsation throughout the flow passage of the prototype and model pump-turbine were roughly similar but exhibited certain differences. Considering the weak compressibility of water, the pressure pulsation fluctuations in each flow passage of the prototype and model pump-turbine exhibit varying degrees of improvement, which is more obvious at the prototype scale. Therefore, the pressure wave disturbance caused by the weak compressibility of the water has different effects on the prototype scale and model scale of the high-head Francis pump-turbine.
Why Subsidize Independent Schools? Estimating the Effect of a Unique Canadian Schooling Model on Educational Attainment
Authors: Lefebvre Pierre , Merrigan Philip
Published: February 2022

Canada is recognized as one of the top 10 countries in secondary education according to PISA results. A particularly intriguing case in this country is the large system of highly subsidized independent schools in the province of Québec where students also perform extremely well in PISA testing. This paper uses the year 2000 PISA cohort of 15-year-olds in Québec to estimate the ATT effect of independent schooling on educational attainment. We find large, positive, robust, and statistically significant effects of independent schooling on attainment. The robustness of the results to omitted variable bias is addressed through a sensitivity analysis for matching estimators.
Tail Conditional Moments for Location-Scale Mixture of Elliptical Distributions
Authors: Han Xiangyu , Yin Chuancun
Published: February 2022

We present the general results on the univariate tail conditional moments for a location-scale mixture of elliptical distributions. Examples include the location-scale mixture of normal, location-scale mixture of Student’s t, location-scale mixture of logistic, and location-scale mixture of Laplace distributions. More specifically, we give the tail variance, the tail conditional skewness, and the tail conditional kurtosis of generalised hyperbolic distribution and Student–GIG mixture distribution. We give an illustrative example, which discusses the TCE, TV, TCS and TCK of three stocks, including Amazon, Google and Apple.
PFVAE: A Planar Flow-Based Variational Auto-Encoder Prediction Model for Time Series Data
Authors: Jin Xue-Bo , Gong Wen-Tao , Kong Jian-Lei , Bai Yu-Ting , Su Ting-Li
Published: February 2022

Prediction based on time series has a wide range of applications. Due to the complex nonlinear and random distribution of time series data, the performance of learning prediction models can be reduced by the modeling bias or overfitting. This paper proposes a novel planar flow-based variational auto-encoder prediction model (PFVAE), which uses the long- and short-term memory network (LSTM) as the auto-encoder and designs the variational auto-encoder (VAE) as a time series data predictor to overcome the noise effects. In addition, the internal structure of VAE is transformed using planar flow, which enables it to learn and fit the nonlinearity of time series data and improve the dynamic adaptability of the network. The prediction experiments verify that the proposed model is superior to other models regarding prediction accuracy and proves it is effective for predicting time series data.
Which Clusters of Metabolic Syndrome Are the Most Associated with Serum Uric Acid?
Authors: Mikolaitytė Jurgita , Badarienė Jolita , Puronaitė Roma , Čypienė Alma , Rutkauskienė Irma , Dadonienė Jolanta , Laucevičius Aleksandras
Published: February 2022

Background and Objectives: Metabolic syndrome is defined as three or more of five components; therefore, there are 16 possible different clusters of metabolic risk factors that are under one diagnosis of metabolic syndrome. In this study, we evaluated the different clusters of metabolic syndrome (MetS) across serum uric acid (SUA) quartiles and analyzed the association of these clusters with SUA levels, respectively, in both men and women. Materials and Methods: A total of 606 subjects were recruited to a cross-sectional study from the ongoing Lithuanian High Cardiovascular Risk primary prevention program (LitHiR). All of the study subjects were diagnosed with MetS (according to the 2005 National Cholesterol Education Program Adult Treatment Panel III MetS definition). Results: In the middle-aged population of patients with MetS living in Lithuania, a high proportion of hyperuricaemia was detected—35.5% (95% Cl 31.7% to 39.4%). For women possessing all five MetS components, the chances of having hyperuricaemia are 2.807 higher than for women with three risk factors (p < 0.001). However, men do not have a statistically significantly higher chance of having hyperuricaemia, depending on the number of MetS components in our population. Using multivariable models, the statistically significant chance of having hyperuricaemia was observed only in women possessing all five MetS components (OR = 2.386, p < 0.0001), compared to any other of 15 MetS clusters. After adjustment for age and sex, the chance of having hyperuricaemia for individuals with the cluster of all five MetS components, compared to any other of 15 MetS clusters, remained (OR = 1.982, p = 0.001). Also, a lower probability (OR = 0.653, p = 0.039) of having hyperuricaemia was observed for individuals having the combination of abnormal plasma glucose, blood pressure, and waist circumference. Conclusions: Patients with the clustering of all five metabolic syndrome components are at higher risk for having hyperuricaemia than patients with any other combination of MetS clusters. This risk is even higher for women. It could be beneficial for patients presented with all five MetS components to be screened for SUA concentration in the primary CVD prevention program.
Prickly Pear Cacti (Opuntia spp.) Cladodes as a Functional Ingredient for Hyperglycemia Management: A Brief Narrative Review
Authors: Kashif Rao Raahim , D’Cunha Nathan M. , Mellor Duane D. , Alexopoulos Natalie I. , Sergi Domenico , Naumovski Nenad
Published: February 2022

The worldwide prevalence of obesity is increasing along with its comorbidities, including type 2 diabetes mellitus (T2DM). From a pathophysiological perspective, T2DM arises as a consequence of insulin resistance and pancreatic β-cell dysfunction, which together induce chronic hyperglycemia. The pharmacological treatment of T2DM specifically focuses on its management, rather than remission, with a lack of pharmacological agents to prevent the onset of the disease. Considering the role of unhealthy dietary patterns on the development of T2DM, identifying novel food ingredients and bioactive substances may provide new avenues by which to address the T2DM epidemic. In this brief review, we have summarized the latest findings on the consumption of the prickly pear (PP; Opuntia spp.) cladode as a potential nutritional tool for the management of hyperglycemia. The consumption of prickly pear cladodes was reported to exert hypoglycemic effects, making it a potential cost-effective nutritional intervention for the management of T2DM. Several studies have demonstrated that the consumption of prickly pear cladodes and the related products reduced post-prandial glucose levels. The cladodes’ high fiber content may be implicated in improving glycemic control, by affecting glucose absorption and effectively slowing its release into the blood circulation. Given these potential hypoglycemic effects, prickly pear cladodes may represent a potential functional food ingredient to improve glycemic control and counter the negative metabolic effects of the modern Western diet. Nonetheless, in consideration of the lack of evidence on the chronic effects of the prickly pear cladode, future research aimed at evaluating its long-term effects on glycemic control is warranted.
The Usefulness of Serological Inflammatory Markers in Patients with Rotator Cuff Disease—A Systematic Review
Authors: Lo Chi Ngai , Leung Bernard Pui Lam , Ngai Shirley Pui Ching
Published: February 2022

Background and Objectives: Rotator cuff disease (RCD) is a prominent musculoskeletal pain condition that spans a variety of pathologies. The etiology and precise diagnostic criteria of this condition remain unclear. The current practice of investigating the biochemical status of RCD is by conducting biopsy studies but their invasiveness is a major limitation. Recent biochemical studies on RCD demonstrate the potential application of serological tests for evaluating the disease which may benefit future clinical applications and research. This systematic review is to summarize the results of available studies on serological biochemical investigations in patients with RCD. Methods: An electronic search on databases PubMed and Virtual Health Library was conducted from inception to 1 September 2021. The inclusion criteria were case-control, cross-sectional, and cohort studies with serological biochemical investigations on humans with RCD. Methodological quality was assessed using the Study Quality Assessment Tool for Observational Cohort and Cross-sectional studies from the National Heart, Lung, and Blood Institute. Results: A total of 6008 records were found in the databases; of these, 163 full-text studies were checked for inclusion and exclusion criteria. Nine eligible studies involving 984 subjects with RCD emerged from this systematic review. The quality of the studies found ranged from poor to moderate. In summarizing all the studies, several fatty acids, nonprotein nitrogen, interleukin-1 β, interleukin-8, and vascular endothelial growth factor were found to be significantly higher in blood samples of patients with RCD than with control group patients, while Omega-3 Intex, vitamin B12, vitamin D, phosphorus, interleukin-10, and angiogenin were observed to be significantly lower. Conclusions: This is the first systematic review to summarize current serological studies in patients with RCD. Results of the studies reflect several systemic physiological changes in patients with RCD, which may prove helpful to better understand the complex pathology of RCD. In addition, the results also indicate the possibility of using serological tests in order to evaluate RCD; however, further longitudinal studies are required.
Polymer Inclusion Membranes
Authors: Rodríguez de San Miguel Eduardo
Published: February 2022

Polymer inclusion membranes (PIMs) are a kind of membrane in which a carrier is physically trapped within a polymer network usually in, but not restricted to, the presence of a plasticizer [...]
P-Loop Channels: Experimental Structures, and Physics-Based and Neural Networks-Based Models
Authors: Tikhonov Denis B. , Zhorov Boris S.
Published: February 2022

The superfamily of P-loop channels includes potassium, sodium, and calcium channels, as well as TRP channels and ionotropic glutamate receptors. A rapidly increasing number of crystal and cryo-EM structures have revealed conserved and variable elements of the channel structures. Intriguing differences are seen in transmembrane helices of channels, which may include π-helical bulges. The bulges reorient residues in the helices and thus strongly affect their intersegment contacts and patterns of ligand-sensing residues. Comparison of the experimental structures suggests that some π-bulges are dynamic: they may appear and disappear upon channel gating and ligand binding. The AlphaFold2 models represent a recent breakthrough in the computational prediction of protein structures. We compared some crystal and cryo-EM structures of P-loop channels with respective AlphaFold2 models. Folding of the regions, which are resolved experimentally, is generally similar to that predicted in the AlphaFold2 models. The models also reproduce some subtle but significant differences between various P-loop channels. However, patterns of π-bulges do not necessarily coincide in the experimental and AlphaFold2 structures. Given the importance of dynamic π-bulges, further studies involving experimental and theoretical approaches are necessary to understand the cause of the discrepancy.
Kinetics of Carbon Partitioning of Q&P Steel: Considering the Morphology of Retained Austenite
Authors: Xu Yaowen , Chen Fei , Li Zhen , Yang Gengwei , Bao Siqian , Zhao Gang , Mao Xinping , Shi Jun
Published: February 2022

The diffusion of carbon atoms from martensite to retained austenite (RA) is controlled by the carbon partitioning kinetics when the quenching and partitioning (Q&P) process is conducted. The RA is divided into film-like and blocky ones in morphology. This research aims to study the influence of the morphology of RA on the kinetics of carbon partitioning mainly by developing a numerical simulation. A one-step Q&P process was modeled at the partitioning temperature of 330–292 °C, with a partitioning time ranging from 10−6 to 5 × 103 s. The finite element method was employed to solve the carbon diffusion equation. A thermomechanical simulator Gleeble-3500 was used to conduct the corresponding Q&P heat treatment, and the RA was examined by X-ray diffraction. The results show that the film-like RA will be enriched in carbon within a short time at first, followed by a decrease in carbon concentration due to the massive absorption of carbon by blocky RA, leading the stable film-like RA to become unstable again. The end of the kinetics of carbon partitioning was the concentration determined by the constrained carbon equilibrium (CCE) model, provided that the CCE condition was employed in this study. It took quite a long time (thousands of seconds) to complete the carbon partitioning globally, which was influenced by the partitioning temperature.
Effects of Low-Frequency Vibrations on Single Point Incremental Sheet Forming
Authors: Xiao Xiao , Oh Se-Hyeon , Kim Sang-Hoon , Kim Young-Suk
Published: February 2022

This study investigated the effects of longitudinal low-frequency vibrations on the performance of the single point incremental forming process of an aluminum alloy 1050 (AA1050) sheet. Low-frequency vibrations were added to the forming tool’s axial movement. A finite element model of low-frequency vibration single point incremental forming was established. Numerical simulation analyzed the effect of low-frequency vibrations on the entire forming process. Then, the simulation results were verified through actual experiments. The results showed that low-frequency vibrations could significantly reduce the forming force and improve the formed product’s geometric accuracy.
Enhancement of Wear Resistance on H13 Tool and Die Steels by Trace Nanoparticles
Authors: Kou Shu-Qing , Dai Jun-Nan , Wang Wen-Xin , Zhang Chun-Kai , Wang Si-Yu , Li Tai-Yu , Chang Fang
Published: February 2022

In order to improve the impact toughness and wear resistance of the tool and die steels, this study innovatively prepared strengthened H13 steels with different contents of single-phase TiC and dual-phase TiC + TiB2 through in situ nanoparticle/Al master alloys at room temperature. The microstructure evolution and mechanical properties as well as wear resistance were investigated. Results indicate that the H13 steel with 0.02 wt.% dual-phase TiC + TiB2 nanoparticles has a more uniform and finer microstructure, and the mechanical properties and wear resistance are significantly improved. The yield strength, maximum tensile strength, breaking strain, uniform elongation, product of strength plasticity, and unnotched and U-notched impact toughness of H13 steel with 0.02 wt.% dual-phase TiC + TiB2 are higher than that of H13 steel. In addition, the volume wear rate, maximum scratch depth and width reach 7.1 × 10−11 m3/m, 6050 nm and 90 μm, respectively, which are reduced by 44.5%, 30.1% and 45.5% compared with that of H13 steel. Refining the microstructure and improving impact toughness and wear resistance of H13 tool steel through trace nanoparticles can provide important inspiration for industrial applications.
Activation Energy Impact on Flow of AA7072-AA7075/Water-Based Hybrid Nanofluid through a Cone, Wedge and Plate
Authors: Rekha Maaliger B. , Sarris Ioannis E. , Madhukesh Javali K. , Raghunatha Kondethimmanahalli R. , Prasannakumara Ballajja C.
Published: February 2022

The present research investigates the effect of a heat source/sink on nanofluid flow through a cone, wedge, and plate when using a suspension of aluminium alloys (AA7072 and AA7075) as nanoparticles in base fluid water. The activation energy and porous material are also considered in the modelling. Using similarity transformations, the modelling equations were converted into an ordinary differential equation (ODEs) system. The Runge Kutta Fehlberg 45 fourth fifth-order (RKF 45) technique and shooting approach were used to numerically solve these equations. The influence of essential aspects on flow fields, heat, and mass transfer rates was studied and addressed using graphical representations. The outcome reveals that the case of fluid flow past a plate shows improved heat transfer for augmented heat source/sink parameter values than the cases for fluid flow past a cone and wedge does. Furthermore, we observed the least heat transfer for the case of fluid flow past the cone. The mass transfer for the case of fluid flow past the cone increased more slowly for growing activation energy parameter values than in the other cases. Moreover, we observed higher mass transfer rates for the case of fluid flow past the plate. The augmented values of the heat source/sink parameter decayed the heat transfer rate in all three flow cases.
Capillary Flow-Driven and Magnetically Actuated Multi-Use Wax Valves for Controlled Sealing and Releasing of Fluids on Centrifugal Microfluidic Platforms
Authors: Peshin Snehan , George Derosh , Shiri Roya , Kulinsky Lawrence , Madou Marc
Published: February 2022

Compact disc (CD)-based centrifugal microfluidics is an increasingly popular choice for academic and commercial applications as it enables a portable platform for biological and chemical assays. By rationally designing microfluidic conduits and programming the disc’s rotational speeds and accelerations, one can reliably control propulsion, metering, and valving operations. Valves that either stop fluid flow or allow it to proceed are critical components of a CD platform. Among the valves on a CD, wax valves that liquify at elevated temperatures to open channels and that solidify at room temperature to close them have been previously implemented on CD platforms. However, typical wax valves on the CD fluidic platforms can be actuated only once (to open or to close) and require complex fabrication steps. Here, we present two new multiple-use wax valve designs, driven by capillary or magnetic forces. One wax valve design utilizes a combination of capillary-driven flow of molten wax and centrifugal force to toggle between open and closed configurations. The phase change of the wax is enabled by heat application (e.g., a 500-mW laser). The second wax valve design employs a magnet to move a molten ferroparticle-laden wax in and out of a channel to enable reversible operation. A multi-phase numerical simulation study of the capillary-driven wax valve was carried out and compared with experimental results. The capillary wax valve parameters including response time, angle made by the sidewall of the wax reservoir with the direction of a valve channel, wax solidification time, minimum spin rate of the CD for opening a valve, and the time for melting a wax plug are measured and analyzed theoretically. Additionally, the motion of the molten wax in a valve channel is compared to its theoretical capillary advance with respect to time and are found to be within 18.75% of the error margin.
Literature Review of Omicron: A Grim Reality Amidst COVID-19
Authors: Arora Suraj , Grover Vishakha , Saluja Priyanka , Algarni Youssef Abdullah , Saquib Shahabe Abullais , Asif Shaik Mohammed , Batra Kavita , Alshahrani Mohammed Y. , Das Gotam , Jain Rajni , Ohri Anchal
Published: February 2022

Coronavirus disease 2019 (COVID-19) first emerged in Wuhan city in December 2019, and became a grave global concern due to its highly infectious nature. The Severe Acute Respiratory Coronavirus-2, with its predecessors (i.e., MERS-CoV and SARS-CoV) belong to the family of Coronaviridae. Reportedly, COVID-19 has infected 344,710,576 people around the globe and killed nearly 5,598,511 persons in the short span of two years. On November 24, 2021, B.1.1.529 strain, later named Omicron, was classified as a Variant of Concern (VOC). SARS-CoV-2 has continuously undergone a series of unprecedented mutations and evolved to exhibit varying characteristics. These mutations have largely occurred in the spike (S) protein (site for antibody binding), which attribute high infectivity and transmissibility characteristics to the Omicron strain. Although many studies have attempted to understand this new challenge in the COVID-19 strains race, there is still a lot to be demystified. Therefore, the purpose of this review was to summarize the structural or virologic characteristics, burden, and epidemiology of the Omicron variant and its potential to evade the immune response.
Mycobacterial Adhesion: From Hydrophobic to Receptor-Ligand Interactions
Authors: Viljoen Albertus , Dufrêne Yves F. , Nigou Jérôme
Published: February 2022

Adhesion is crucial for the infective lifestyles of bacterial pathogens. Adhesion to non-living surfaces, other microbial cells, and components of the biofilm extracellular matrix are crucial for biofilm formation and integrity, plus adherence to host factors constitutes a first step leading to an infection. Adhesion is, therefore, at the core of pathogens’ ability to contaminate, transmit, establish residency within a host, and cause an infection. Several mycobacterial species cause diseases in humans and animals with diverse clinical manifestations. Mycobacterium tuberculosis, which enters through the respiratory tract, first adheres to alveolar macrophages and epithelial cells leading up to transmigration across the alveolar epithelium and containment within granulomas. Later, when dissemination occurs, the bacilli need to adhere to extracellular matrix components to infect extrapulmonary sites. Mycobacteria causing zoonotic infections and emerging nontuberculous mycobacterial pathogens follow divergent routes of infection that probably require adapted adhesion mechanisms. New evidence also points to the occurrence of mycobacterial biofilms during infection, emphasizing a need to better understand the adhesive factors required for their formation. Herein, we review the literature on tuberculous and nontuberculous mycobacterial adhesion to living and non-living surfaces, to themselves, to host cells, and to components of the extracellular matrix.
Combination of High-Pressure Treatment at 500 MPa and Biopreservation with a Lactococcus lactis Strain for Lowering the Bacterial Growth during Storage of Diced Cooked Ham with Reduced Nitrite Salt
Authors: Chaillou Stéphane , Ramaroson Mihanta , Coeuret Gwendoline , Rossero Albert , Anthoine Valérie , Champomier-Vergès Marie , Moriceau Nicolas , Rezé Sandrine , Martin Jean-Luc , Guillou Sandrine , Zagorec Monique
Published: February 2022

We investigated the combined effects of biopreservation and high-pressure treatment on bacterial communities of diced cooked ham prepared with diminished nitrite salt. First, bacterial communities of four commercial brands of diced cooked ham from local supermarkets were characterized and stored frozen. Second, sterile diced cooked ham, prepared with reduced levels of nitrite, was inoculated with two different microbiota collected from the aforementioned commercial samples together with a nisin-producing Lactococcus lactis protective strain able to recover from a 500 MPa high-pressure treatment. Samples were then treated at 500 MPa for 5 min, and bacterial dynamics were monitored during storage at 8 °C. Depending on samples, the ham microbiota was dominated by different Proteobacteria (Pseudomonas, Serratia, Psychrobacter, or Vibrio) or by Firmicutes (Latilactobacillus and Leuconostoc). Applied alone, none of the treatments stabilized during the growth of the ham microbiota. Nevertheless, the combination of biopreservation and high-pressure treatment was efficient in reducing the growth of Proteobacteria spoilage species. However, this effect was dependent on the nature of the initial microbiota, showing that the use of biopreservation and high-pressure treatment, as an alternative to nitrite reduction for ensuring cooked ham microbial safety, merits attention but still requires improvement.
Modeling Interfacial Tension of N2/CO2 Mixture + n-Alkanes with Machine Learning Methods: Application to EOR in Conventional and Unconventional Reservoirs by Flue Gas Injection
Authors: Salehi Erfan , Mohammadi Mohammad-Reza , Hemmati-Sarapardeh Abdolhossein , Mahdavi Vahid Reza , Gentzis Thomas , Liu Bo , Ostadhassan Mehdi
Published: February 2022

The combustion of fossil fuels from the input of oil refineries, power plants, and the venting or flaring of produced gases in oil fields leads to greenhouse gas emissions. Economic usage of greenhouse and flue gases in conventional and unconventional reservoirs would not only enhance the oil and gas recovery but also offers CO2 sequestration. In this regard, the accurate estimation of the interfacial tension (IFT) between the injected gases and the crude oils is crucial for the successful execution of injection scenarios in enhanced oil recovery (EOR) operations. In this paper, the IFT between a CO2/N2 mixture and n-alkanes at different pressures and temperatures is investigated by utilizing machine learning (ML) methods. To this end, a data set containing 268 IFT data was gathered from the literature. Pressure, temperature, the carbon number of n-alkanes, and the mole fraction of N2 were selected as the input parameters. Then, six well-known ML methods (radial basis function (RBF), the adaptive neuro-fuzzy inference system (ANFIS), the least square support vector machine (LSSVM), random forest (RF), multilayer perceptron (MLP), and extremely randomized tree (extra-tree)) were used along with four optimization methods (colliding bodies optimization (CBO), particle swarm optimization (PSO), the Levenberg–Marquardt (LM) algorithm, and coupled simulated annealing (CSA)) to model the IFT of the CO2/N2 mixture and n-alkanes. The RBF model predicted all the IFT values with exceptional precision with an average absolute relative error of 0.77%, and also outperformed all other models in this paper and available in the literature. Furthermore, it was found that the pressure and the carbon number of n-alkanes would show the highest influence on the IFT of the CO2/N2 and n-alkanes, based on sensitivity analysis. Finally, the utilized IFT database and the area of the RBF model applicability were investigated via the leverage method.
Origin and Composition of Ferromanganese Deposits of New Caledonia Exclusive Economic Zone
Authors: Staszak Paul , Collot Julien , Josso Pierre , Pelleter Ewan , Etienne Samuel , Patriat Martin , Cheron Sandrine , Boissier Audrey , Guyomard Yaël
Published: February 2022

Located in the South-West Pacific, at the northern extremity of the mostly submerged Zealandia continent, the New Caledonian Exclusive Economic Zone (EEZ) covers 1,470,000 km² and includes basins, ridges and seamounts where abundant ferromanganese crusts have been observed. Several investigations have been conducted since the 1970s on the nature and composition of ferromanganese crusts from New Caledonia’s seamounts and ridges, but none have covered the entire EEZ. We present data from 104 ferromanganese crusts collected in New Caledonia’s EEZ during twelve oceanographic cruises between 1974 and 2019. Samples were analysed for mineralogy, geochemical compositions, growth rates, and through a statistical approach using correlation coefficients and factor analysis. Crust thicknesses range from 1 mm to 115 mm, with growth rates between 0.45 mm/Ma and 102 mm/Ma. Based on textures, structures, discrimination plots, and growth rates, we distinguish a group of hydrogenetic crusts containing the highest mean contents of Co (0.42 wt%), Ni (0.31 wt%), and high contents of Mo, V, W, Pb, Zn, Nb, from a group of hydrothermal and/or diagenetic deposits showing high mean contents of Mn (38.17 wt%), Ba (0.56 wt%) and low contents of other trace metals. Several samples from this later group have exceptionally high content of Ni (0.7 wt%). The data shows that crusts from the southern part of the EEZ, notably seamounts of the Loyalty Ridge and the Lord Howe Rise, present high mineral potential for prospectivity owing to high contents of valuable metals, and constitute a great target for further investigation.
Determination of Antioxidants by DPPH Radical Scavenging Activity and Quantitative Phytochemical Analysis of Ficus religiosa
Authors: Baliyan Siddartha , Mukherjee Riya , Priyadarshini Anjali , Vibhuti Arpana , Gupta Archana , Pandey Ramendra Pati , Chang Chung-Ming
Published: February 2022

The use of F. religiosa might be beneficial in inflammatory illnesses and can be used for a variety of health conditions. In this article, we studied the identification of antioxidants using (DPPH) 2,2-Diphenyl-1-picrylhydrazylradical scavenging activity in Ficus religiosa, as F. religiosa is an important herbal plant, and every part of it has various medicinal properties such as antibacterial properties that can be used by the researchers in the development and design of various new drugs. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) is a popular, quick, easy, and affordable approach for the measurement of antioxidant properties that includes the use of the free radicals used for assessing the potential of substances to serve as hydrogen providers or free-radical scavengers (FRS). The technique of DPPH testing is associated with the elimination of DPPH, which would be a stabilized free radical. The free-radical DPPH interacts with an odd electron to yield a strong absorbance at 517 nm, i.e., a purple hue. An FRS antioxidant, for example, reacts to DPPH to form DPPHH, which has a lower absorbance than DPPH because of the lower amount of hydrogen. It is radical in comparison to the DPPH-H form, because it causes decolorization, or a yellow hue, as the number of electrons absorbed increases. Decolorization affects the lowering capacity significantly. As soon as the DPPH solutions are combined with the hydrogen atom source, the lower state of diphenylpicrylhydrazine is formed, shedding its violet color. To explain the processes behind the DPPH tests, as well as their applicability to Ficus religiosa (F. religiosa) in the manufacture of metal oxide nanoparticles, in particular MgO, and their influence on antioxidants, a specimen from the test was chosen for further study. According to our findings, F. religiosa has antioxidant qualities and may be useful in the treatment of disorders caused by free radicals.
The Role of Lipids in Allosteric Modulation of Dopamine D2 Receptor—In Silico Study
Authors: Żuk Justyna , Bartuzi Damian , Miszta Przemysław , Kaczor Agnieszka A.
Published: February 2022

The dopamine D2 receptor, belonging to the class A G protein-coupled receptors (GPCRs), is an important drug target for several diseases, including schizophrenia and Parkinson’s disease. The D2 receptor can be activated by the natural neurotransmitter dopamine or by synthetic ligands, which in both cases leads to the receptor coupling with a G protein. In addition to receptor modulation by orthosteric or allosteric ligands, it has been shown that lipids may affect the behaviour of membrane proteins. We constructed a model of a D2 receptor with a long intracellular loop (ICL3) coupled with Giα1 or Giα2 proteins, embedded in a complex asymmetric membrane, and simulated it in complex with positive, negative or neutral allosteric ligands. In this study, we focused on the influence of ligand binding and G protein coupling on the membrane–receptor interactions. We show that there is a noticeable interplay between the cell membrane, G proteins, D2 receptor and its modulators.
Biofortification—A Frontier Novel Approach to Enrich Micronutrients in Field Crops to Encounter the Nutritional Security
Authors: Dhaliwal Salwinder Singh , Sharma Vivek , Shukla Arvind Kumar , Verma Vibha , Kaur Manmeet , Shivay Yashbir Singh , Nisar Shahida , Gaber Ahmed , Brestic Marian , Barek Viliam , Skalicky Milan , Ondrisik Peter , Hossain Akbar
Published: February 2022

Globally, many developing countries are facing silent epidemics of nutritional deficiencies in human beings and animals. The lack of diversity in diet, i.e., cereal-based crops deficient in mineral nutrients is an additional threat to nutritional quality. The present review accounts for the significance of biofortification as a process to enhance the productivity of crops and also an agricultural solution to address the issues of nutritional security. In this endeavor, different innovative and specific biofortification approaches have been discussed for nutrient enrichment of field crops including cereals, pulses, oilseeds and fodder crops. The agronomic approach increases the micronutrient density in crops with soil and foliar application of fertilizers including amendments. The biofortification through conventional breeding approach includes the selection of efficient genotypes, practicing crossing of plants with desirable nutritional traits without sacrificing agricultural and economic productivity. However, the transgenic/biotechnological approach involves the synthesis of transgenes for micronutrient re-translocation between tissues to enhance their bioavailability. Soil microorganisms enhance nutrient content in the rhizosphere through diverse mechanisms such as synthesis, mobilization, transformations and siderophore production which accumulate more minerals in plants. Different sources of micronutrients viz. mineral solutions, chelates and nanoparticles play a pivotal role in the process of biofortification as it regulates the absorption rates and mechanisms in plants. Apart from the quality parameters, biofortification also improved the crop yield to alleviate hidden hunger thus proving to be a sustainable and cost-effective approach. Thus, this review article conveys a message for researchers about the adequate potential of biofortification to increase crop productivity and nourish the crop with additional nutrient content to provide food security and nutritional quality to humans and livestock.
Alkaloids in Future Drug Discovery
Authors: Ferreira Maria-José U.
Published: February 2022

Alkaloids are nitrogen-containing compounds, biosynthesized by both marine and terrestrial organisms, often with strong biological properties [...]
Ultralight MOF-Derived Ni3S2@N, S-Codoped Graphene Aerogels for High-Performance Microwave Absorption
Authors: Yu Wenjing , Liu Bo , Zhao Xiaojiao
Published: February 2022

To develop high-performance microwave absorption materials with the features of lightweight, thin thickness, broad bandwidth, and strong absorption, an ultralight Ni3S2@N, S-codoped graphene aerogel with a density of 13.5 mg/cm3 has been fabricated by the use of metal-organic frameworks (MOFs) to directly initiate the gelation of graphene oxide strategy. In such a strategy, dual-functional 1D Ni-MOF nanorods not only act as the gelation agent but also afford the doping elements (N and S) originated from the organic species and the precursor for metal sulfide. Due to the synergistic effects of good impedance matching and multiple losses, the optimal reflection loss (RL) of as-prepared Ni3S2@N, S-codoped graphene aerogel reaches −46.9 dB at 17.1 GHz with only 2.0 mm and ultralow filling content (1.75 wt%). The maximum effective absorption bandwidth (EAB) reaches 6.3 GHz (11.7–18.0 GHz) at 2.38 mm, covering the whole Ku band. Moreover, the value of EAB with the RL less than −30 dB can be tuned to 12.2 GHz (5.8–18 GHz) at the absorber thickness ranging from 1.9 to 5.0 mm. This work provides insight for rational design and fabrication of multicomponent-containing graphene aerogels, showing the potential application in lightweight and high-performance microwave absorption.
Lower Limits of Contact Resistance in Phosphorene Nanodevices with Edge Contacts
Authors: Poljak Mirko , Matić Mislav , Župančić Tin , Zeljko Ante
Published: February 2022

Edge contacts are promising for improving carrier injection and contact resistance in devices based on two-dimensional (2D) materials, among which monolayer black phosphorus (BP), or phosphorene, is especially attractive for device applications. Cutting BP into phosphorene nanoribbons (PNRs) widens the design space for BP devices and enables high-density device integration. However, little is known about contact resistance (RC) in PNRs with edge contacts, although RC is the main performance limiter for 2D material devices. Atomistic quantum transport simulations are employed to explore the impact of attaching metal edge contacts (MECs) on the electronic and transport properties and contact resistance of PNRs. We demonstrate that PNR length downscaling increases RC to 192 Ω µm in 5.2 nm-long PNRs due to strong metallization effects, while width downscaling decreases the RC to 19 Ω µm in 0.5 nm-wide PNRs. These findings illustrate the limitations on PNR downscaling and reveal opportunities in the minimization of RC by device sizing. Moreover, we prove the existence of optimum metals for edge contacts in terms of minimum metallization effects that further decrease RC by ~30%, resulting in lower intrinsic quantum limits to RC of ~90 Ω µm in phosphorene and ~14 Ω µm in ultra-narrow PNRs.