bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Through-the-Thickness Delamination Position on the R-Curve Behavior of Plain-Woven ENF Specimens
Authors: Salamat-Talab Mazaher , Akhavan-Safar Alireza , Zeinolabedin-Beygi Ali , Carbas Ricardo J. C. , da Silva Lucas F. M.
Published: February 2023

In this study, the effect of through-the-thickness delamination plane position on the R-curve behavior of end-notch-flexure (ENF) specimens was investigated using experimental and numerical procedures. From the experimental point of view, plain-woven E-glass/epoxy ENF specimens with two different delamination planes, i.e., [012//012] and [017//07], were manufactured by hand lay-up method. Afterward, fracture tests were conducted on the specimens by aiding ASTM standards. The main three parameters of R-curves, including the initiation and propagation of mode II interlaminar fracture toughness and the fracture process zone length, were analyzed. The experimental results revealed that changing the delamination position in ENF specimen has a negligible effect on the initiation and steady steady-state toughness values of delamination. In the numerical part, the virtual crack closure technique (VCCT) was used in order to analyze the imitation delamination toughness as well as the contribution of another mode on the obtained delamination toughness. The numerical results indicated that by choosing an appropriate value of cohesive parameters, the trilinear cohesive zone model (CZM) is capable of predicting the initiation as well as propagation of the ENF specimens. Finally, the damage mechanisms at the delaminated interface were investigated with microscopic images taken using a scanning electron microscope.
Numerical Studies of the Impact of Electromagnetic Field of Radiation on Valine
Authors: Kirova Teodora , Tamuliene Jelena
Published: February 2023

We present the results of numerical calculations of the effect of an electromagnetic field of radiation on valine, and compare them to experimental results available in the literature. We specifically focus on the effects of a magnetic field of radiation, by introducing modified basis sets, which incorporate correction coefficients to the s-, p- or only the p-orbitals, following the method of anisotropic Gaussian-type orbitals. By comparing the bond length, angle, dihedral angles, and condense-to-atom-all electrons, obtained without and with the inclusion of dipole electric and magnetic fields, we concluded that, while the charge redistribution occurs due to the electric field influence, the changes in the dipole momentum projection onto the y- and z- axes are caused by the magnetic field. At the same time, the values of the dihedral angles could vary by up to 4 degrees, due to the magnetic field effects. We further show that taking into account the magnetic field in the fragmentation processes provides better fitting of the experimentally obtained spectra: thus, numerical calculations which include magnetic field effects can serve as a tool for better predictions, as well as for analysis of the experimental outcomes.
Double-Reinforced Fish Gelatin Composite Scaffolds for Osteochondral Substitutes
Authors: Toader Alin Georgian , Vlasceanu George Mihail , Serafim Andrada , Banciu Adela , Ionita Mariana
Published: February 2023

Genipin crosslinked composite blends of fish gelatin/kappa-carrageenan (fG/κC) with different concentrations of graphene oxide (GO) for osteochondral substitutes were prepared by a simple solution-blending method. The resulting structures were examined by micro-computer tomography, swelling studies, enzymatic degradations, compressions tests, MTT, LDH, and LIVE/DEAD assays. The derived findings revealed that genipin crosslinked fG/κC blends reinforced with GO have a homogenous morphology with ideal pore dimensions of 200–500 µm for bones alternative. GO additivation with a concentration above 1.25% increased the blends’ fluid absorption. The full degradation of the blends occurs in 10 days and the gel fraction stability increases with GO concentration. The blend compression modules decrease at first until fG/κC GO3, which has the least elastic behavior, then by raising the GO concentration the blends start to regain elasticity. The MC3T3-E1 cell viability reveals less viable cells with the increase of GO concentration. The LDH together with the LIVE/DEAD assays reports a high concentration of live and healthy cells in all types of composite blends and very few dead cells at the higher GO content.
Effects of K2TiF6 and Electrolyte Temperatures on Energy Consumption and Properties of MAO Coatings on 6063 Aluminum Alloy
Authors: Xie Xiaomeng , Yang Erhui , Zhang Ziying , Wei Wu , Li Dong , Zhao Xiaolian , Yang Ruixia , Li Weizhou
Published: February 2023

To decrease energy consumption and improve the performance of micro-arc oxidation (MAO) films on 6063 Al alloy, a policy of K2TiF6 additive and electrolyte temperature control was adapted. The specific energy consumption relied on the K2TiF6 additive and more particularly on the electrolyte temperatures. Scanning electron microscopy demonstrates that electrolytes with 5 g/L K2TiF6 can effectively seal the surface pores and increase the thickness of the compact inner layer. Spectral analysis shows that the surface oxide coating consists of γ-Al2O3 phase. Following 336 h of the total immersion process, the impedance modulus of the oxidation film, prepared at 25 °C (Ti5-25), remained 1.08 × 106 Ω·cm2. Moreover, Ti5-25 has the best performance/energy-consumption ratio with a compact inner layer (2.5 ± 0.3 μm). This research found that the time of the big arc stage increased with the temperature, resulting in producing more internal defects in the film. In this work, we employ a dual-track strategy of additive and temperature providing an avenue to reduce the energy consumption of MAO on alloys.
Photothermal Hyperthermia Study of Ag/Ni and Ag/Fe Plasmonic Particles Synthesized Using Dual-Pulsed Laser
Authors: Ali Imran , Chen Jun , Ahmed Khan Saeed , Jamil Yasir , Shah Aqeel Ahmed , Shah Abdul Karim , Gilani Sadaf Jamal , Bin Jumah May Nasser , Fazal Yusra , Pan Yunxiang , Shen Zhonghua
Published: February 2023

Magneto-plasmonic Ag/Ni and Ag/Fe nanoparticles (NPs) were synthesized in this work using the environmentally safe and contaminant-free dual-pulsed Q-switched Nd:YAG 1064 nm laser ablation method. The optical and magnetic characteristics of synthesized nanomaterials were investigated using a vibrating sample magnetometer and an ultraviolet-visible absorption spectrometer. According to transmission electron microscopy (TEM), the shape of Ag/Ni and Ag/Fe NPs seems to be spherical, with mean diameters of 7.3 nm and 11.5 nm, respectively. X-ray diffraction (XRD) was used in order to investigate and describe the phase structures of the synthesized nanomaterials. The synthesized NPs reached maximum temperatures such as 48.9, 60, 63.4, 70, 75, and 79 °C for Ag/Ni nanofluid and 52, 56, 60, 68, 71, and 72 °C for Ag/Fe nanofluid when these nanofluids were subjected to an NIR 808 nm laser with operating powers of 1.24, 1.76, 2.36, 2.91, 3.5, and 4 W, respectively. Because of the plasmonic hyperthermia properties of nanoparticles, nanofluids display higher temperature profiles than pure water. According to these findings, plasmonic nanoparticles based on silver might be used to treat hyperthermia.
Insights into the 3D Slip Dynamics of Jeffrey Fluid Due to a Rotating Disk with Exponential Space-Dependent Heat Generation: A Case Involving a Non-Fourier Heat Flux Model
Authors: Alshomrani Ali Saleh
Published: February 2023

The dynamics of non-Newtonian Jeffrey fluid in conjunction with a spinning disk surface can be problematic in heating systems, polymer technology, microelectronics, advanced technology, and substantive disciplines. Therefore, the significance of the Hall current and Coriolis forces in terms of the dynamics of Jeffrey fluid flowing across a gyrating disk subject to non-Fourier heat flux was investigated in this study. A temperature-related heat source (TRHS) and exponential-related heat source (ERHS) were incorporated into the model to improve the thermal characteristics. Thermal radiation and multiple slip effects were employed in the flow system. The connected non-linear PDEs governing the transport were transmuted into non-linear ODEs and solved using the Runge–Kutta shooting technique (RKST). The results of the RKST were substantiated in previous studies and found to have adequate reliability. The numerical values of the coefficient of friction and the Nusselt number were simulated. The non-Fourier heat flux was found to have a higher rate of heat transfer (HTR) than with traditional Fourier heat flux. Furthermore, both TRHS and ERHS phenomena support the progression of HTR. The swelling effects of the Hall current influence the velocities, whilst the temperature of the Jeffrey fluid shows the opposite tendency. Furthermore, asymptotic variances were detected for larger Hall parameter values.
Transient Finite-Speed Heat Transfer Influence on Deformation of a Nanoplate with Ultrafast Circular Ring Heating
Authors: Fayik Mohsen , Alhazmi Sharifah E. , Abdou Mohamed A. , Awad Emad
Published: February 2023

The present study provides a theoretical estimate for the thermal stress distribution and the displacement vector inside a nano-thick infinite plate due to an exponentially temporal decaying boundary heating on the front surface of the elastic plate. The surface heating is in the form of a circular ring; therefore, the axisymmetric formulation is adopted. Three different hyperbolic models of thermal transport are considered: the Maxwell-Cattaneo-Vernotte (MCV), hyperbolic Dual-Phase-Lag (HDPL) and modified hyperbolic Dual-Phase-Lag (MHDPL), which coincides with the two-step model under certain constraints. A focus is directed to the main features of the corresponding hyperbolic thermoelastic models, e.g., finite-speed thermal waves, singular surfaces (wave fronts) and wave reflection on the rear surface of the plate. Explicit expressions for the thermal and mechanical wave speeds are derived and discussed. Exact solution for the temperature in the short-time domain is derived when the thermalization time on the front surface is very long. The temperature, hydrostatic stress and displacement vector are represented in the space-time domain, with concentrating attention on the thermal reflection phenomenon on the thermally insulated rear surface. We find that the mechanical wave speeds are approximately equal for the considered models, while the thermal wave speeds are entirely different such that the modified hyperbolic dual-phase-lag thermoelasticity has the faster thermal wave speed and the Lord-Shulman thermoelasticity has the slower thermal wave speed.
A Fuzzy Plug-and-Play Neural Network-Based Convex Shape Image Segmentation Method
Authors: Zhang Xuyuan , Han Yu , Lin Sien , Xu Chen
Published: February 2023

The task of partitioning convex shape objects from images is a hot research topic, since this kind of object can be widely found in natural images. The difficulties in achieving this task lie in the fact that these objects are usually partly interrupted by undesired background scenes. To estimate the whole boundaries of these objects, different neural networks are designed to ensure the convexity of corresponding image segmentation results. To make use of well-trained neural networks to promote the performances of convex shape image segmentation tasks, in this paper a new image segmentation model is proposed in the variational framework. In this model, a fuzzy membership function, instead of a classical binary label function, is employed to indicate image regions. To ensure fuzzy membership functions can approximate to binary label functions well, an edge-preserving smoothness regularizer is constructed from an off-the-shelf plug-and-play network denoiser, since an image denoising process can also be seen as an edge-preserving smoothing process. From the numerical results, our proposed method could generate better segmentation results on real images, and our image segmentation results were less affected by the initialization of our method than the results obtained from classical methods.
Derivation of the Fractional Fokker–Planck Equation for Stable Lévy with Financial Applications
Authors: Aljethi Reem Abdullah , Kılıçman Adem
Published: February 2023

This paper aims to propose a generalized fractional Fokker–Planck equation based on a stable Lévy stochastic process. To develop the general fractional equation, we will use the Lévy process rather than the Brownian motion. Due to the Lévy process, this fractional equation can provide a better description of heavy tails and skewness. The analytical solution is chosen to solve the fractional equation and is expressed using the H-function to demonstrate the indicator entropy production rate. We model market data using a stable distribution to demonstrate the relationships between the tails and the new fractional Fokker–Planck model, as well as develop an R code that can be used to draw figures from real data.
Analysis of the In-Host Dynamics of Tuberculosis and SARS-CoV-2 Coinfection
Authors: Elaiw Ahmed M. , Agha Afnan D. Al
Published: February 2023

The coronavirus disease 2019 (COVID-19) is a respiratory disease that appeared in 2019 caused by a virus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 is still spreading and causing deaths around the world. There is a real concern of SARS-CoV-2 coinfection with other infectious diseases. Tuberculosis (TB) is a bacterial disease caused by Mycobacterium tuberculosis (Mtb). SARS-CoV-2 coinfection with TB has been recorded in many countries. It has been suggested that the coinfection is associated with severe disease and death. Mathematical modeling is an effective tool that can help understand the dynamics of coinfection between new diseases and well-known diseases. In this paper, we develop an in-host TB and SARS-CoV-2 coinfection model with cytotoxic T lymphocytes (CTLs). The model investigates the interactions between healthy epithelial cells (ECs), latent Mtb-infected ECs, active Mtb-infected ECs, SARS-CoV-2-infected ECs, free Mtb, free SARS-CoV-2, and CTLs. The model’s solutions are proved to be nonnegative and bounded. All equilibria with their existence conditions are calculated. Proper Lyapunov functions are selected to examine the global stability of equilibria. Numerical simulations are implemented to verify the theoretical results. It is found that the model has six equilibrium points. These points reflect two states: the mono-infection state where SARS-CoV-2 or TB occurs as a single infection, and the coinfection state where the two infections occur simultaneously. The parameters that control the movement between these states should be tested in order to develop better treatments for TB and COVID-19 coinfected patients. Lymphopenia increases the concentration of SARS-CoV-2 particles and thus can worsen the health status of the coinfected patient.
High Order Energy Preserving Composition Method for Multi-Symplectic Sine-Gordon Equation
Authors: Sun Jianqiang , Zhang Jingxian , Kong Jiameng
Published: February 2023

A fourth-order energy preserving composition scheme for multi-symplectic structure partial differential equations have been proposed. The accuracy and energy conservation properties of the new scheme were verified. The new scheme is applied to solve the multi-symplectic sine-Gordon equation with periodic boundary conditions and compared with the corresponding second-order average vector field scheme and the second-order Preissmann scheme. The numerical experiments show that the new scheme has fourth-order accuracy and can preserve the energy conservation properties well.
A Systematic Review on the Solution Methodology of Singularly Perturbed Differential Difference Equations
Authors: Duressa Gemechis File , Daba Imiru Takele , Deressa Chernet Tuge
Published: February 2023

This review paper contains computational methods or solution methodologies for singularly perturbed differential difference equations with negative and/or positive shifts in a spatial variable. This survey limits its coverage to singular perturbation equations arising in the modeling of neuronal activity and the methods developed by numerous researchers between 2012 and 2022. The review covered singularly perturbed ordinary delay differential equations with small or large negative shift(s), singularly perturbed ordinary differential–differential equations with mixed shift(s), singularly perturbed delay partial differential equations with small or large negative shift(s) and singularly perturbed partial differential–difference equations of the mixed type. The main aim of this review is to find out what numerical and asymptotic methods were developed in the last ten years to solve such problems. Further, it aims to stimulate researchers to develop new robust methods for solving families of the problems under consideration.
Constrained Self-Adaptive Physics-Informed Neural Networks with ResNet Block-Enhanced Network Architecture
Authors: Zhang Guangtao , Yang Huiyu , Pan Guanyu , Duan Yiting , Zhu Fang , Chen Yang
Published: February 2023

Physics-informed neural networks (PINNs) have been widely adopted to solve partial differential equations (PDEs), which could be used to simulate physical systems. However, the accuracy of PINNs does not meet the needs of the industry, and severely degrades, especially when the PDE solution has sharp transitions. In this paper, we propose a ResNet block-enhanced network architecture to better capture the transition. Meanwhile, a constrained self-adaptive PINN (cSPINN) scheme is developed to move PINN’s objective to the areas of the physical domain, which are difficult to learn. To demonstrate the performance of our method, we present the results of numerical experiments on the Allen–Cahn equation, the Burgers equation, and the Helmholtz equation. We also show the results of solving the Poisson equation using cSPINNs on different geometries to show the strong geometric adaptivity of cSPINNs. Finally, we provide the performance of cSPINNs on a high-dimensional Poisson equation to further demonstrate the ability of our method.
Tourism Employment and Economic Growth: Dynamic Panel Threshold Analysis
Authors: Vuković Darko B. , Maiti Moinak , Petrović Marko D.
Published: February 2023

The manuscript reports on findings on the interconnection between tourism employment and economic growth for the selected OECD member states. The dynamic panel threshold regression method was used to analyze the data, where the threshold variable was tourism employment, and the growth of gross national income and value added by activity services were dependent variables in the corresponding models. The dataset covered the period between 2008 and 2020. Both marginal effects indicated positive implications of tourism employment on economic growth. A percent rise in tourism employment leads to an increase in gross national income by 0.15% (in the low regime) and 0.61% (in the high regime). Yet, the results revealed a negative marginal effect of tourism employment on value added by activity services. The outcomes explain that a percent rise in tourism employment in the average country will lead to a decrease in the value added by activity services, as a percentage of value added, by 0.07% (low regime) and 0.09% (high regime). Therefore, the applications of this study are twofold—the first one is its contribution to existing theoretical knowledge through the filling of the literature gaps, and the second one is related to advances in the standing policies. The main limitations and the proposal for future research are the application of random effects and smooth transition threshold models as an alternative to the indicator functions.
Infinitesimal Transformations of Riemannian Manifolds—The Geometric Dynamics Point of View
Authors: Rýparová Lenka , Hinterleitner Irena , Stepanov Sergey , Tsyganok Irina
Published: February 2023

In the present paper, we study the geometry of infinitesimal conformal, affine, projective, and harmonic transformations of complete Riemannian manifolds using the concepts of geometric dynamics and the methods of the modern version of the Bochner technique.
Comparison of Statistical Production Models for a Solar and a Wind Power Plant
Authors: Meghea Irina
Published: February 2023

Mathematical models to characterize and forecast the power production of photovoltaic and eolian plants are justified by the benefits of these sustainable energies, the increased usage in recent years, and the necessity to be integrated into the general energy system. In this paper, starting from two collections of data representing the power production hourly measured at a solar plant and a wind farm, adequate time series methods have been used to draw appropriate statistical models for their productions. The data are smoothed in both cases using moving average and continuous time series have been obtained leading to some models in good agreement with experimental data. For the solar power plant, the developed models can predict the specific power of the next day, next week, and next month, with the most accurate being the monthly model, while for wind power only a monthly model could be validated. Using the CUSUM (cumulative sum control chart) method, the analyzed data formed stationary time series with seasonality. The similar methods used for both sets of data (from the solar plant and wind farm) were analyzed and compared. When compare with other studies which propose production models starting from different measurements involving meteorological data and/or machinery characteristics, an innovative element of this paper consists in the data set on which it is based, this being the production itself. The novelty and the importance of this research reside in the simplicity and the possibility to be reproduced for other related conditions even though every new set of data (provided from other power plants) requires further investigation.
Brushless Operation of Wound-Rotor Synchronous Machine Based on Sub-Harmonic Excitation Technique Using Multi-Pole Stator Windings
Authors: Humza Muhammad , Yazdan Tanveer , Ali Qasim , Cho Han-Wook
Published: February 2023

This paper presents a topology for the brushless operation of a wound-rotor synchronous machine based on the subharmonic excitation technique by using two sets of multi-pole windings on the armature as well as on the rotor. The armature windings consist of a four-pole three-phase main winding and a two-pole single-phase additional winding, responsible for the generation of fundamental and subharmonic components of magnetomotive force (MMF), respectively. The rotor contains four-pole field winding and two-pole excitation winding. From the generated air gap MMF, the additional winding is responsible for induction in excitation winding, which feeds DC to the field winding through a rotating rectifier without the need of brushes. Then, the interaction of the magnetic field from the main and the field windings produces torque. The proposed topology is analyzed using 2D finite element analysis (FEM). From the analysis, the generation of the subharmonic component of MMF is verified, which helps in achieving the brushless operation of the wound-rotor synchronous machine. Furthermore, the performance of the proposed brushless multi-pole topology is compared with the existing dual three-phase winding multi-pole topology in terms of current due to induction, output torque, torque ripples, and efficiency.
Protist–Lactic Acid Bacteria Co-Culture as a Strategy to Bioaccumulate Polyunsaturated Fatty Acids in the Protist Aurantiochytrium sp. T66
Authors: Marileo Luis , Acuña Jacqueline , Rilling Joaquin , Díaz Paola , Langellotti Antonio Luca , Russo Giovanni Luca , Barra Patricio Javier , Dantagnan Patricio , Viscardi Sharon
Published: February 2023

Thraustochytrids are aquatic unicellular protists organisms that represent an important reservoir of a wide range of bioactive compounds, such as essential polyunsaturated fatty acids (PUFAs) such as arachidonic acid (ARA), docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), which are involved in the regulation of the immune system. In this study, we explore the use of co-cultures of Aurantiochytrium sp. and bacteria as a biotechnological tool capable of stimulating PUFA bioaccumulation. In particular, the co-culture of lactic acid bacteria and the protist Aurantiochytrium sp. T66 induce PUFA bioaccumulation, and the lipid profile was evaluated in cultures at different inoculation times, with two different strains of lactic acid bacteria capable of producing the tryptophan dependent auxins, and one strain of Azospirillum sp., as a reference for auxin production. Our results showed that the Lentilactobacillus kefiri K6.10 strain inoculated at 72 h gives the best PUFA content (30.89 mg g−1 biomass) measured at 144 h of culture, three times higher than the control (8.87 mg g−1 biomass). Co-culture can lead to the generation of complex biomasses with higher added value for developing aquafeed supplements.
Combined Electrodialysis and Electrocoagulation as Treatment for Industrial Wastewater Containing Arsenic and Copper
Authors: Hansen Henrik K. , Gutiérrez Claudia , Leiva Gonzalez Jorge , Lazo Andrea , Hansen Marcela E. , Lazo Pamela , Ottosen Lisbeth M. , Ortiz Rodrigo
Published: February 2023

In copper smelting processes, acidic effluents are generated that contain inorganic contaminants such as arsenic and copper. Nowadays, the treatment of wastewater is done by physicochemical methods without copper recovery. Electrodialysis is an alternative process that can recover copper. Moreover, when electrocoagulation is applied to remove arsenic from wastewater, a more stable final sludge of less volume is obtained. The present research studies the application of a combined electrodialysis and electrocoagulation process to (1) recover Cu and (2) precipitate and remove arsenic simultaneously in the same batch reactor, using synthetic wastewater that simulates wastewater from a copper smelter. Copper and arsenic could be removed and separated by the electrodialysis part, and the electrocoagulation of arsenic was verified. With electrodialysis, the arsenic and copper removals were 67% and 100%, respectively, while 82% of the arsenic arriving at the electrocoagulation part of the cell could be precipitated and removed by this process. Initial concentrations were around 815 mg L−1 Cu and 7700 mg L−1 As. The optimal current was found to be 1.36 A due to the shorter treatment times necessary to get removal percentages, recovery percentages and energy/removed copper mass ratios in the same ranges as the values achieved with a current of 1.02 A. In summary, the combined process is a promising tool for simultaneous copper recovery and arsenic removal.
Spall Failure of ECAE Mg-Al Alloys at Extreme Strain Rates: Influence of a Refined Precipitate and Grain Microstructure
Authors: DiMarco Christopher S. , Lim Peter , Mallick Debjoy , Kecskes Laszlo , Weihs Timothy P. , Ramesh K. T.
Published: February 2023

The development of advanced materials for extreme dynamic environments requires an understanding of the links between the microstructure and the response of the material (i.e., Materials-by-Design). Spall failure significantly limits material performance at high strain rates, but our understanding of the influence of microstructure on spall strength is limited. While models suggest that increasing the static yield strength by adding precipitates or refining grain size can improve the spall strength, it is possible that the associated increase in nucleation sites may have deleterious effects on spall performance. Herein, we examine spall failure of a Magnesium-Aluminum system with precipitation and grain size strengthening through novel high-throughput laser-driven micro-flyer (LDMF) impact experiments. Six microstructures are investigated, four with grain sizes around 2–3 μm and precipitates around 0.5–1 μm, and two that are precipitate-free with grain sizes around 500 μm at six and nine percent Aluminum contents. The LDMF method allows us to detect differences in spall strength with relatively small changes in microstructure. The spall strength is observed to be strongly affected by varying levels of precipitates and consistently shows a notable reduction in average spall strength around 8–19% with the addition of precipitates, with values ranging from 1.22–1.50 GPa. The spall strength is also seen to decrease with the refinement of grain size independent of composition. However, this decrease is small compared to the hundred-fold grain size reduction. While ductile void growth is observed across all samples, greater variability and a further decrease in strength are seen with an increasing numbers of non-uniformly dispersed precipitates.
Screening for Antifungal Indigenous Lactobacilli Strains Isolated from Local Fermented Milk for Developing Bioprotective Fermentates and Coatings Based on Acid Whey Protein Concentrate for Fresh Cheese Quality Maintenance
Authors: Vasiliauskaite Agne , Mileriene Justina , Kasparaviciene Beatrice , Aleksandrovas Elvidas , Songisepp Epp , Rud Ida , Axelsson Lars , Muizniece-Brasava Sandra , Ciprovica Inga , Paskevicius Algimantas , Aksomaitiene Jurgita , Gabinaitiene Ausra , Uljanovas Dainius , Baliukoniene Violeta , Lutter Liis , Malakauskas Mindaugas , Serniene Loreta
Published: February 2023

The demand for healthy foods without artificial food additives is constantly increasing. Hence, natural food preservation methods using bioprotective cultures could be an alternative to chemical preservatives. Thus, the main purpose of this work was to screen the indigenous lactobacilli isolated from fermented cow milk for their safety and antifungal activity to select the safe strain with the strongest fungicidal properties for the development of bioprotective acid whey protein concentrate (AWPC) based fermentates and their coatings intended for fresh cheese quality maintenance. Therefore, 12 lactobacilli strains were isolated and identified from raw fermented cow milk as protective cultures. The safety of the stains was determined by applying antibiotic susceptibility, haemolytic and enzymatic evaluation. Only one strain, Lacticaseibacillus paracasei A11, met all safety requirements and demonstrated a broad spectrum of antifungal activity in vitro. The strain was cultivated in AWPC for 48 h and grew well (biomass yield 8 log10 cfu mL−1). L. paracasei A11 AWPC fermentate was used as a vehicle for protective culture in the development of pectin-AWPC-based edible coating. Both the fermentate and coating were tested for their antimicrobial properties on fresh acid-curd cheese. Coating with L. paracasei A11 strain reduced yeast and mould counts by 1.0–1.5 log10 cfu mL−1 (p ≤ 0.001) during cheese storage (14 days), simultaneously preserving its flavour and prolonging the shelf life for six days.
Biosynthesis of Novel Tellurium Nanorods by Gayadomonas sp. TNPM15 Isolated from Mangrove Sediments and Assessment of Their Impact on Spore Germination and Ultrastructure of Phytopathogenic Fungi
Authors: Abd El-Ghany Mohamed N. , Hamdi Salwa A. , Korany Shereen M. , Elbaz Reham M. , Farahat Mohamed G.
Published: February 2023

The biosynthesis of nanoparticles using green technology is emerging as a cost-efficient, eco-friendly and risk-free strategy in nanotechnology. Recently, tellurium nanoparticles (TeNPs) have attracted growing attention due to their unique properties in biomedicine, electronics, and other industrial applications. The current investigation addresses the green synthesis of TeNPs using a newly isolated mangrove-associated bacterium, Gayadomonas sp. TNPM15, and their impact on the phytopathogenic fungi Fusarium oxysporum and Alternaria alternata. The biogenic TeNPs were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared (FTIR). The results of TEM revealed the intracellular biosynthesis of rod-shaped nanostructures with a diameter range from 15 to 23 nm and different lengths reaching up to 243 nm. Furthermore, the successful formation of tellurium nanorods was verified by SEM-EDX, and the XRD pattern revealed their crystallinity. In addition, the FTIR spectrum provided evidence for the presence of proteinaceous capping agents. The bioinspired TeNPs exhibited obvious inhibitory effect on the spores of both investigated phytopathogens accomplished with prominent ultrastructure alternations, as evidenced by TEM observations. The biogenic TeNPs impeded spore germination of F. oxysporum and A. alternata completely at 48.1 and 27.6 µg/mL, respectively. Furthermore, an increase in DNA and protein leakage was observed upon exposure of fungal spores to the biogenic TeNPs, indicating the disruption of membrane permeability and integrity. Besides their potent influence on fungal spores, the biogenic TeNPs demonstrated remarkable inhibitory effects on the production of various plant cell wall-degrading enzymes. Moreover, the cytotoxicity investigations revealed the biocompatibility of the as-prepared biogenic TeNPs and their low toxicity against the human skin fibroblast (HSF) cell line. The biogenic TeNPs showed no significant cytotoxic effect towards HSF cells at concentrations up to 80 μg/mL, with a half-maximal inhibitory concentration (IC50) value of 125 μg/mL. The present work spotlights the antifungal potential of the biogenic TeNPs produced by marine bacterium against phytopathogenic fungi as a promising candidate to combat fungal infections.
Radical Pairing Interactions and Donor–Acceptor Interactions in Cyclobis(paraquat-p-phenylene) Inclusion Complexes
Authors: Wang Wei , Wu Wei , Su Peifeng
Published: February 2023

Understanding molecular interactions in mechanically interlocked molecules (MIMs) is challenging because they can be either donor–acceptor interactions or radical pairing interactions, depending on the charge states and multiplicities in the different components of the MIMs. In this work, for the first time, the interactions between cyclobis(paraquat-p-phenylene) (abbreviated as CBPQTn+ (n = 0–4)) and a series of recognition units (RUs) were investigated using the energy decomposition analysis approach (EDA). These RUs include bipyridinium radical cation (BIPY•+), naphthalene-1,8:4,5-bis(dicarboximide) radical anion (NDI•−), their oxidized states (BIPY2+ and NDI), neutral electron-rich tetrathiafulvalene (TTF) and neutral bis-dithiazolyl radical (BTA•). The results of generalized Kohn–Sham energy decomposition analysis (GKS-EDA) reveal that for the CBPQTn+···RU interactions, correlation/dispersion terms always have large contributions, while electrostatic and desolvation terms are sensitive to the variation in charge states in CBPQTn+ and RU. For all the CBPQTn+···RU interactions, desolvation terms always tend to overcome the repulsive electrostatic interactions between the CBPQT cation and RU cation. Electrostatic interaction is important when RU has the negative charge. Moreover, the different physical origins of donor–acceptor interactions and radical pairing interactions are compared and discussed. Compared to donor–acceptor interactions, in radical pairing interactions, the polarization term is always small, while the correlation/dispersion term is important. With regard to donor–acceptor interactions, in some cases, polarization terms could be quite large due to the electron transfer between the CBPQT ring and RU, which responds to the large geometrical relaxation of the whole systems.
Sugar Beet Pulp as a Biorefinery Substrate for Designing Feed
Authors: Dygas Dawid , Kręgiel Dorota , Berłowska Joanna
Published: February 2023

An example of the implementation of the principles of the circular economy is the use of sugar beet pulp as animal feed. Here, we investigate the possible use of yeast strains to enrich waste biomass in single-cell protein (SCP). The strains were evaluated for yeast growth (pour plate method), protein increment (Kjeldahl method), assimilation of free amino nitrogen (FAN), and reduction of crude fiber content. All the tested strains were able to grow on hydrolyzed sugar beet pulp-based medium. The greatest increases in protein content were observed for Candida utilis LOCK0021 and Saccharomyces cerevisiae Ethanol Red (ΔN = 2.33%) on fresh sugar beet pulp, and for Scheffersomyces stipitis NCYC1541 (ΔN = 3.04%) on dried sugar beet pulp. All the strains assimilated FAN from the culture medium. The largest reductions in the crude fiber content of the biomass were recorded for Saccharomyces cerevisiae Ethanol Red (Δ = 10.89%) on fresh sugar beet pulp and Candida utilis LOCK0021 (Δ = 15.05%) on dried sugar beet pulp. The results show that sugar beet pulp provides an excellent matrix for SCP and feed production.
Hydrogen/Deuterium Exchange Mass Spectrometry for Probing the Isomeric Forms of Oleocanthal and Oleacin in Extra Virgin Olive Oils
Authors: Abbattista Ramona , Losito Ilario , Basile Graziana , Castellaneta Andrea , Ventura Giovanni , Calvano Cosima Damiana , Cataldi Tommaso R. I.
Published: February 2023

Reversed-phase liquid chromatography and electrospray ionization with Fourier-transform single and tandem mass spectrometry (RPLC-ESI-FTMS and FTMS/MS) were employed for the structural characterization of oleocanthal (OLEO) and oleacin (OLEA), two of the most important bioactive secoiridoids occurring in extra virgin olive oils (EVOOs). The existence of several isoforms of OLEO and OLEA was inferred from the chromatographic separation, accompanied, in the case of OLEA, by minor peaks due to oxidized OLEO recognized as oleocanthalic acid isoforms. The detailed analysis of the product ion tandem MS spectra of deprotonated molecules ([M-H]−) was unable to clarify the correlation between chromatographic peaks and specific OLEO/OLEA isoforms, including two types of predominant dialdehydic compounds, named Open Forms II, containing a double bond between carbon atoms C8 and C10, and a group of diasteroisomeric closed-structure (i.e., cyclic) isoforms, named Closed Forms I. This issue was addressed by H/D exchange (HDX) experiments on labile H atoms of OLEO and OLEA isoforms, performed using deuterated water as a co-solvent in the mobile phase. HDX unveiled the presence of stable di-enolic tautomers, in turn providing key evidence for the occurrence, as prevailing isoforms, of Open Forms II of OLEO and OLEA, different from those usually considered so far as the main isoforms of both secoiridoids (having a C=C bond between C8 and C9). It is expected that the new structural details inferred for the prevailing isoforms of OLEO and OLEA will help in understanding the remarkable bioactivity exhibited by the two compounds.
Structurally Different Exogenic Brassinosteroids Protect Plants under Polymetallic Pollution via Structure-Specific Changes in Metabolism and Balance of Cell-Protective Components
Authors: Zlobin Ilya E. , Danilova Elena D. , Murgan Ol’ga K. , Kolomeichuk Liliya V. , Litvinovskaya Raisa P. , Sauchuk Alina L. , Kuznetsov Vladimir V. , Efimova Marina V.
Published: February 2023

Heavy metals and aluminum are among the most significant abiotic factors that reduce the productivity and quality of crops in acidic and contaminated soils. The protective effects of brassinosteroids containing lactone are relatively well-studied under heavy metal stress, but the effects of brassinosteroids containing ketone are almost unstudied. Moreover, there are almost no data in the literature on the protective role of these hormones under polymetallic stress. The aim of our study was to compare the stress-protective effects of lactone-containing (homobrassinolide) and ketone-containing (homocastasterone) brassinosteroids on the barley plant’s resistance to polymetallic stress. Barley plants were grown under hydroponic conditions; brassinosteroids, increased concentrations of heavy metals (Mn, Ni, Cu, Zn, Cd, and Pb), and Al were added to the nutrient medium. It was found that homocastasterone was more effective than homobrassinolide in mitigating the negative effects of stress on plant growth. Both brassinosteroids had no significant effect on the antioxidant system of plants. Both homobrassinolide and homocastron equally reduced the accumulation of toxic metals (except for Cd) in plant biomass. Both hormones improved Mg nutrition of plants treated with metal stress, but the positive effect on the content of photosynthetic pigments was observed only for homocastasterone and not for homobrassinolide. In conclusion, the protective effect of homocastasterone was more prominent compared to homobrassinolide, but the biological mechanisms of this difference remain to be elucidated.
Extraction of Valuable Biomolecules from the Microalga Haematococcus pluvialis Assisted by Electrotechnologies
Authors: Gherabli Adila , Grimi Nabil , Lemaire Julien , Vorobiev Eugène , Lebovka Nikolai
Published: February 2023

The freshwater microalga Haematococcus pluvialis is well known as the cell factory for natural astaxanthin, which composes up to 4–7% of its total dry weight. The bioaccumulation of astaxanthin in H. pluvialis cysts seems to be a very complex process that depends on different stress conditions during its cultivation. The red cysts of H. pluvialis develop thick and rigid cell walls under stress growing conditions. Thus, the biomolecule extraction requires general cell disruption technologies to reach a high recovery rate. This short review provides an analysis of the different steps in H. pluvialis’s up and downstream processing including cultivation and harvesting of biomass, cell disruption, extraction and purification techniques. Useful information on the structure of H. pluvialis’s cells, biomolecular composition and properties and the bioactivity of astaxanthin is collected. Special emphasis is given to the recent progress in application of different electrotechnologies during the growth stages and for assistance of the recovery of different biomolecules from H. pluvialis.
Synthesis and Functional Characterization of CoxFe3−xO4-BaTiO3 Magnetoelectric Nanocomposites for Biomedical Applications
Authors: Nizamov Timur R. , Amirov Abdulkarim A. , Kuznetsova Tatiana O. , Dorofievich Irina V. , Bordyuzhin Igor G. , Zhukov Dmitry G. , Ivanova Anna V. , Gabashvili Anna N. , Tabachkova Nataliya Yu. , Tepanov Alexander A. , Shchetinin Igor V. , Abakumov Maxim A. , Savchenko Alexander G. , Majouga Alexander G.
Published: February 2023

Nowadays, magnetoelectric nanomaterials are on their way to finding wide applications in biomedicine for various cancer and neurological disease treatment, which is mainly restricted by their relatively high toxicity and complex synthesis. This study for the first time reports novel magnetoelectric nanocomposites of CoxFe3−xO4-BaTiO3 series with tuned magnetic phase structures, which were synthesized via a two-step chemical approach in polyol media. The magnetic CoxFe3−xO4 phases with x = 0.0, 0.5, and 1.0 were obtained by thermal decomposition in triethylene glycol media. The magnetoelectric nanocomposites were synthesized by the decomposition of barium titanate precursors in the presence of a magnetic phase under solvothermal conditions and subsequent annealing at 700 °C. X-ray diffraction revealed the presence of both spinel and perovskite phases after annealing with average crystallite sizes in the range of 9.0–14.5 nm. Transmission electron microscopy data showed two-phase composite nanostructures consisting of ferrites and barium titanate. The presence of interfacial connections between magnetic and ferroelectric phases was confirmed by high-resolution transmission electron microscopy. Magnetization data showed expected ferrimagnetic behavior and σs decrease after the nanocomposite formation. Magnetoelectric coefficient measurements after the annealing showed non-linear change with a maximum of 89 mV/cm*Oe with x = 0.5, 74 mV/cm*Oe with x = 0, and a minimum of 50 mV/cm*Oe with x = 0.0 core composition, that corresponds with the coercive force of the nanocomposites: 240 Oe, 89 Oe and 36 Oe, respectively. The obtained nanocomposites show low toxicity in the whole studied concentration range of 25–400 μg/mL on CT-26 cancer cells. The synthesized nanocomposites show low cytotoxicity and high magnetoelectric effects, therefore they can find wide applications in biomedicine.
Profile of a Food-Insecure College Student at a Major Southeastern University: A Randomized Cross-Sectional Study
Authors: Harville Cedric , James Delores C. S. , Burns Arné
Published: February 2023

Ten percent of Americans are food-insecure. Few known studies have accessed college food insecurity via random sampling. An online cross-sectional survey (n = 1087) was distributed via email to a random sample of undergraduate college students. Food insecurity was determined by the USDA Food Security Short Form. Data were analyzed using JMP Pro. Results: Thirty-six percent of the students were food-insecure. Most food-insecure students were enrolled full-time (93.6%), female (81.2%), received financial aid (77.9%), lived off-campus (75.0%), non-white (59.6%), and employed (51.7%). Food-insecure students had a significantly lower GPA (p < 0.001 *), were more likely to be non-white (p < 0.0001 *), and were more likely to have received financial aid compared to food-secure students (p < 0.0001 *). Food-insecure students were significantly more likely to have lived in government housing, had free or reduced lunch, used SNAP and WIC benefits, and received food from a food bank during childhood (p < 0.0001 * for all). Food-insecure students were significantly less likely to report that they experienced a food shortage to counseling and wellness personnel, a resident assistant, and their parents (p < 0.05 * for all). Discussion: College students might be at greater risk for food insecurity if they are non-white, first-generation students, employed, on financial aid, and have a history of accessing government assistance during childhood.
Assessment of Fatty Acid Content in the Milk of Women from the West Pomeranian Region of Poland with Regard to Supplementation and the Amount of Adipose Tissue
Authors: Ćwiek Dorota , Zimny Małgorzata , Szymoniak Katarzyna , Czechowska Krystyna , Sipak-Szmigiel Olimpia
Published: February 2023

The total amount of fat in the milk of nursing mothers depends on maternal reserves, as well as food intake and its synthesis in the mammary glands. The aim of this study was to assess the contents of fatty acids in the milk of women from the West Pomeranian region of Poland with regards to supplementation and the amount of adipose tissue. We also wanted to find out whether these women, who have direct access to the sea and potential access to fresh marine fish, have higher levels of DHA. Methods: We analyzed milk samples obtained 6–7 weeks postpartum from 60 women. The content of fatty acid methyl esters (FAME) in lipids was determined by gas chromatography–mass spectrometry (GC/MS) using a Clarus 600 device (PerkinElmer). Results: Women using dietary supplements had significantly higher levels of docosahexaenoic acid (DHA) (C22:6 n-3) (p = 0.000) and eicosapentaenoic acid (EPA) (20:5 n-3) (p = 0.000). The levels of eicosatrienoic acid (ETA) (C20:3 n-3) and γ-linolenic acid (GLA) increased with the amount of body fat, and the level of DHA was lowest in subjects where body fat exceeded 40% (p = 0.036). Conclusions: The contents of fatty acids in the milk of women from the West Pomeranian region of Poland were similar to that reported by other authors. The levels of DHA in women using dietary supplements was also comparable to the values reported worldwide. BMI had an effect on the levels of ETE and GLA acids.