bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Non-Identical Magnetic Fields on Thermomagnetic Convective Flow of a Nanoliquid Using Buongiorno’s Model
Authors: Khedher Nidhal Ben , Sheremet Mikhail , Saif Alghawli Abed , Mohamed Abdullah , Mehryan Seyed Abdollah Mansouri
Published: April 2022

Energy transport intensification is a major challenge in various technical applications including heat exchangers, solar collectors, electronics, and others. Simultaneously, the control of energy transport and liquid motion allows one to predict the development of the thermal process. The present work deals with the computational investigation of nanoliquid thermogravitational energy transport in a square region with hot cylinders along walls under non-uniform magnetic influences. Two current-carrying wires as non-identical magnetic sources are set in the centers of two heated half-cylinders mounted on the bottom and left borders, while the upper wall is kept at a constant low temperature. Buongiorno’s model was employed with the impact of Brownian diffusion and thermophoresis. Governing equations considering magnetohydrodynamic and ferrohydrodynamic theories were solved by the finite element technique. The effects of the magnetic sources strengths ratio, Lewis number, Hartmann number, magnetic number, buoyancy ratio, Brownian motion characteristic, and thermophoresis feature on circulation structures and heat transport performance were examined. For growth of magnetism number between 0 and 103 one can find an increment of heat transfer rate for the half-cylinder mounted on the bottom wall and a reduction of heat transfer rate for the half-cylinder mounted on the left wall, while for an increase in magnetism number between 103 and 104, the opposite effects occur. Moreover, a rise in the Lewis number characterizes the energy transport degradation. Additionally, an intensification of energy transport could be achieved by a reduction of the thermophoresis parameter, while the Brownian diffusion factor and buoyancy ratio have a negligible influence on energy transport. Furthermore, the heat transfer rate through the half-cylinder mounted on the bottom wall declines with an increase in the magnetic sources strengths ratio.
Inverse Analysis for the Convergence-Confinement Method in Tunneling
Authors: Lee Yu-Lin , Kao Wei-Cheng , Chen Chih-Sheng , Ma Chi-Huang , Hsieh Pei-Wen , Lee Chi-Min
Published: April 2022

For the safety of tunnel excavation, the observation of tunnel convergence not only provides a technique for assessing the stability of the surrounding ground, but also provides an estimate of the constitutive parameters of geological materials. This estimation method belongs to an inverse algorithm process called the inverse calculation method (ICM), which utilizes the incremental concept in the convergence-confinement method (CCM) to solve the support-ground interaction of circular tunnel excavation. The method is to determine the mathematical solution of the intersection of the two nonlinear curves, the support confining curve (SCC) and the ground reaction curve (GRC) in the CCM by using Newton’s recursive method and inversely calculating the unknown parameters. To verify the validity of the developed inverse algorithm process, this study compares the results of the ICM with those of the published articles. In addition, the modulus of rock mass and unsupported span are inversely deduced using the values of convergence difference measured in the practical case of railway tunnels.
Unsupervised Fault Diagnosis of Sucker Rod Pump Using Domain Adaptation with Generated Motor Power Curves
Authors: Hao Dezhi , Gao Xianwen
Published: April 2022

The poor real-time performance and high maintenance costs of the dynamometer card (DC) sensors have been significant obstacles to the timely fault diagnosis in the sucker rod pumping system (SRPS). In contrast to the DCs, the motor power curves (MPCs), which are accessible easily and highly associated with the entire system, have been attempted to predict the working conditions of the SRPS in recent years. However, the lack of labeled MPCs limits the successful applications in the industrial scenario. Thereby, this paper presents an unsupervised fault diagnosis methodology to leverage the generated MPCs of different working conditions to diagnose the actual unlabeled MPCs. Firstly, the MPCs of six working conditions are generated with an integrated dynamics mathematical model. Secondly, a framework named mechanism-assisted domain adaptation network (MADAN) is proposed to minimize the distribution discrepancy between the generated and actual MPCs. Specifically, benefiting from introducing the mechanism analysis to label the collected MPCs preliminarily, a conditional distribution discrepancy metric is defined to guarantee a more accurate distribution matching with respect to different working conditions. Eventually, validation experiments are performed to evaluate the mathematical model and the diagnosis method with a set of actual MPCs collected by a self-developed device. The experimental result demonstrates that the proposed method offers a promising approach for the unsupervised diagnosis of the SRPS.
Optimizing PV Microgrid Isolated Electrification Projects—A Case Study in Ecuador
Authors: Domenech Bruno , Ferrer-Martí Laia , García Facundo , Hidalgo Georgina , Pastor Rafael , Ponsich Antonin
Published: April 2022

Access to electricity for the rural and indigenous population of Ecuador’s Amazon Region (RAE) is considered a critical issue by the national authorities. The RAE is an isolated zone with communities scattered throughout the rainforest, where the expansion of the national grid is not a viable option. Therefore, autonomous electrification systems based on solar energy constitute an important solution, allowing the development of indigenous populations. This work proposes a tool for the design of stand-alone rural electrification systems based on photovoltaic technologies, including both microgrid or individual supply configurations. This tool is formulated as a Mixed Integer Linear Programming model including economic, technical and social aspects. This approach is used to design electrification systems (equipment location and sizing, microgrid configurations) in three real communities of the RAE. The results highlight the benefits of the developed tool and provide guidelines regarding RAE’s electrification.
Peculiar Features of Quantum Oscillator Excitation by Pulses with Different Envelopes
Authors: Astapenko Valery
Published: April 2022

We investigate the excitation of a quantum harmonic oscillator by pulses with different envelopes in terms of the excitation probability during the action of a pulse. The majority of attention is given to the dependence of the probability on the pulse duration and the pulse carrier frequency for three envelopes: exponential, double exponential, and rectangular. The choice of these envelopes makes it possible to cover various features of the excitation of a quantum oscillator by an external pulse. In particular, the presence of weak and strong excitation modes is established, for each of which the dependences of the process probability on pulse parameters are studied.
A Correlation-Embedded Attention Module to Mitigate Multicollinearity: An Algorithmic Trading Application
Authors: Chan Jireh Yi-Le , Leow Steven Mun Hong , Bea Khean Thye , Cheng Wai Khuen , Phoong Seuk Wai , Hong Zeng-Wei , Lin Jim-Min , Chen Yen-Lin
Published: April 2022

Algorithmic trading is a common topic researched in the neural network due to the abundance of data available. It is a phenomenon where an approximately linear relationship exists between two or more independent variables. It is especially prevalent in financial data due to the interrelated nature of the data. The existing feature selection methods are not efficient enough in solving such a problem due to the potential loss of essential and relevant information. These methods are also not able to consider the interaction between features. Therefore, we proposed two improvements to apply to the Long Short-Term Memory neural network (LSTM) in this study. It is the Multicollinearity Reduction Module (MRM) based on correlation-embedded attention to mitigate multicollinearity without removing features. The motivation of the improvements is to allow the model to predict using the relevance and redundancy within the data. The first contribution of the paper is allowing a neural network to mitigate the effects of multicollinearity without removing any variables. The second contribution is improving trading returns when our proposed mechanisms are applied to an LSTM. This study compared the classification performance between LSTM models with and without the correlation-embedded attention module. The experimental result reveals that a neural network that can learn the relevance and redundancy of the financial data to improve the desired classification performance. Furthermore, the trading returns of our proposed module are 46.82% higher without sacrificing training time. Moreover, the MRM is designed to be a standalone module and is interoperable with existing models.
Evolutionary Exploration of Mechanical Assemblies in VR
Authors: Kim Won Gyu , Lee Kang Hoon
Published: April 2022

Due to the maker movement and 3D printers, people nowadays can directly fabricate mechanical devices that meet their own objectives. However, it is not intuitive to identify the relationship between specific mechanical movements and mechanical structures that facilitate such movements. This paper presents an interactive system that can enable users to easily create and experiment with desired mechanical assemblies via direct manipulation interfaces in virtual reality, as well as to intuitively explore design space through repeated application of the crossover operation, which is used at the core of the genetic algorithm. Specifically, a mechanical assembly in our system is genetically encoded as a undirected graph structure in which each node corresponds to a mechanical part and each edge represents the connection between parts. As the user selects two different mechanical assemblies and commands the crossover operation, each of their corresponding graphs is split into two subgraphs and those subgraphs are recombined to generate the next-generation mechanical assemblies. The user can visually examine new mechanical assemblies, save assemblies that are closer to objectives, and remove the others. Based on our experiments, in which non-expert participants were asked to achieve a challenging design objective, it was verified that the proposed interface exhibited significantly effective performance.
A Family of Position Values for Directed Communication Situations
Authors: Gavilán Elena C. , Manuel Conrado M. , Van Den Brink René
Published: April 2022

In this paper, we define a family of values for directed communication situations that are inspired by the position value. We use the concept of directed communication and related connectedness in directed graphs, under which a coalition of players in a game can only cooperate if these players form a directed path in a directed communication graph. By defining an arc game, which assesses the worth of coalitions of (directed) arcs in generating worth, we allocate the Shapley value payoff of each arc over the nodes incident with this arc, where we allow the head and tail to obtain a different share in this arc payoff. However, the way that the arc payoff is shared over its head and tail is uniform over all arcs. We characterize these values by connection efficiency and a modification of the classical balanced link contributions property for undirected communication situations, discriminating between the roles of the nodes as head and tail.
Design of an LMI-Based Fuzzy Fast Terminal Sliding Mode Control Approach for Uncertain MIMO Systems
Authors: Mokhtare Zahra , Vu Mai The , Mobayen Saleh , Fekih Afef
Published: April 2022

This paper proposes a linear matrix inequality (LMI)-based fuzzy fast terminal sliding mode control (FFTSM) approach for a multi-input multi-output (MIMO) system. This design aims to achieve the finite-time convergence of system trajectories to their desired values, while at the same time eliminating the chattering problem. Finite-time stability is proven using the Lyapunov theory and the control parameters are obtained using the LMI approach. The fuzzy logic approach is considered to fine tune the controller parameters and reduce the tracking error and control signal amplitude. The performance of the proposed approach is assessed using a simulation study of a direct current (DC) motor. The obtained results confirm the effectiveness of the proposed control design. Simplicity of the design, robustness, finite-time convergence, and chattering-free dynamics are among the features of the proposed approach.
Blind Image Deblurring via a Novel Sparse Channel Prior
Authors: Yang Dayi , Wu Xiaojun , Yin Hefeng
Published: April 2022

Blind image deblurring (BID) is a long-standing challenging problem in low-level image processing. To achieve visually pleasing results, it is of utmost importance to select good image priors. In this work, we develop the ratio of the dark channel prior (DCP) to the bright channel prior (BCP) as an image prior for solving the BID problem. Specifically, the above two channel priors obtained from RGB images are used to construct an innovative sparse channel prior at first, and then the learned prior is incorporated into the BID tasks. The proposed sparse channel prior enhances the sparsity of the DCP. At the same time, it also shows the inverse relationship between the DCP and BCP. We employ the auxiliary variable technique to integrate the proposed sparse prior information into the iterative restoration procedure. Extensive experiments on real and synthetic blurry sets show that the proposed algorithm is efficient and competitive compared with the state-of-the-art methods and that the proposed sparse channel prior for blind deblurring is effective.
Characterizing Tasks for Teaching Mathematics in Dynamic Geometry System and Modelling Environments
Authors: Guerrero-Ortiz Carolina , Camacho-Machín Matías
Published: April 2022

With an empirical study, we explore the process of designing modeling tasks for teaching mathematics in a Dynamic Geometry environment. We address the research questions: What are the characteristics of the tasks that pre-service teachers design to teach mathematics in digital and modeling environments? What are the activities like that these tasks encourage in students? By means of a qualitative methodology, we characterize the tasks designed by secondary pre-service mathematics teachers and identify the activities that these tasks encourage in students. By analyzing the process of designing and planning a class, we can determine how the characteristics of the modeling tasks are modified based on the software used. In this context, the software also acts as a medium that reflects aspects of the models involved, the objectives of the tasks, and the activities intended for the students. The results contribute to the discussion regarding task design, where technology is a means of supporting the exploration, understanding, and study of different phenomena.
Tunable Multi-Band-Stop Filters Using Generalized Fibonacci Photonic Crystals for Optical Communication Applications
Authors: Ali Naim Ben , Alshammari Serhan , Trabelsi Youssef , Alsaif Haitham , Kahouli Omar , Elleuch Zied
Published: April 2022

In this study, a numerical investigation of photonic quasi-periodic Generalized Fibonacci (GF) (m, n) sequences is carried out in the visible spectrum. The transfer matrix method is employed to study the behavior of wave propagation through the photonic structures. Firstly and to highlight the importance of the GF structure, its transmittance spectrum is compared to those of periodic and ordinary Fibonacci structures. It is shown that the GF structure permits one to obtain multi-photonic band gaps (PBGs) separated by several resonance modes. The variation in the parameter m of the GF (m, 1) structure allows for the tuning of the number, the position and the width of these bands. By changing the parameter m, the wavelengths (650, 850, 1300, and 1550 nm) of the plastic and glass optical fibers can be allowed or forbidden to transmit through the structure according to the value of this parameter. In contrast, the variation in the parameter n for GF (1, n) hides all PBGs and only permits the appearance of several Kiessig fringes. The proposed structures can find application as tunable multi-band-stop filters for optical fiber wavelengths.
Identification of a De Novo Deletion by Using A-CGH Involving PLNAX2: An Interesting Candidate Gene in Psychomotor Developmental Delay
Authors: Falcone Noemi , Ranieri Annaluisa , Vitale Andrea , Pastore Lucio , Lombardo Barbara
Published: April 2022

Psychomotor developmental delay is a disorder with a prevalence of 12–18% in the pediatric population, characterized by the non-acquisition of motor, cognitive and communication skills during the child’s development, in relation to chronological age. An appropriate neuropsychomotor evaluation and the use of new technologies, such as Array Comparative Genomic Hybridization (a-CGH) and Next-generation sequencing (NGS), can contribute to early diagnosis and improving the quality of life. In this case, we have analyzed a boy aged 2 years and 8 months, with a diagnosis of psychomotor developmental delay, mainly in the area of communication and language. The a-CGH analysis identified three de novo deletions of uncertain clinical significance, involving PLXNA2 (1q32.2), PRELID2, GRXCR2 and SH3RF2 (5q32), RIMS1 (6q13), and a heterozygous duplication of maternal origin involved three genes: HELZ, PSMD12 and PITPNC1 (17q24.2). Among all these alterations, our attention focused on the PLXNA2 gene because of the central function that plexin 2 carries out in the development of the central nervous system. However, all genes detected in the analysis could contribute to the phenotypic characteristics of the patient.
Quality of Life, Psychological Wellbeing, and Sexuality in Women with Urinary Incontinence—Where Are We Now: A Narrative Review
Authors: Frigerio Matteo , Barba Marta , Cola Alice , Braga Andrea , Celardo Angela , Munno Gaetano , Schettino Maria , Vagnetti Primo , De Simone Fulvio , Di Lucia Alessandra , Grassini Giulia , Torella Marco
Published: April 2022

Urinary incontinence (UI) is a very common condition, negatively affecting social, occupational, domestic, and psychophysical wellbeing. In particular, a peculiar and detrimental effect of UI has been described concerning sexual function. However, the impact of UI on quality of life is not fully understood yet, and further investigation into this issue is warranted. With this narrative review, we aimed to report the current evidence from recent literature regarding the quality of life and psychological wellbeing in patients with urinary incontinence, with a special focus on sexual function and its evolution after UI treatment. There is strong evidence that urinary incontinence—in its different forms, including stress urinary incontinence, urge urinary incontinence, mixed urinary incontinence, and coital urinary incontinence—negatively affects female sexual function. Treatments aimed to cure urinary incontinence—including pelvic floor muscles training, medications, and surgery—seem to improve quality of life by recovering, at least in part, sexual function. In conclusion, there is a substantial association between involuntary urinary loss and sex life quality. However, few studies are available and more evidence is needed before consistent conclusions can be made.
Substantially High Hidden Blood Loss in Oblique Lateral Interbody Fusion: Retrospective Case Series
Authors: Shima Koichiro , Sono Takashi , Kitaori Toshiyuki , Takatsuka Kazutaka
Published: April 2022

Background and Objectives: Measured blood loss frequently underestimates true blood loss; this discrepancy is called hidden blood loss (HBL). The purpose of the present study was to measure HBL in oblique lateral interbody fusion (OLIF). Materials and Methods: Patients who underwent two-stage OLIF at our institute from September 2017 to September 2021 were retrospectively reviewed. Total blood loss (TBL) and HBL were calculated using the gross formula. The age, sex, body mass index (BMI), operation time, measured blood loss, the number of fused segments, hematocrit (HCT), anticoagulant or platelet medication, blood transfusion, days of hospitalization, pre-/postoperative Japanese Orthopedic Association (JOA) score, and JOA recovery rate were compared. Results: A total of thirteen patients were included in the study. The average age, BMI, number of fused segments, operation time, estimated blood loss, and blood transfusion were 69.5 years, 23.3, 2.5, 250 min, 122 mL, and 230 mL, respectively. Five patients received anticoagulant or platelet therapy. Days of hospitalization, pre-/postoperative JOA score, and JOA recovery rate were 14.9 ± 5.1, 19.9 ± 2.7, and 18.0 ± 43.4%, respectively. The TBL and HBL were 688 and 797 mL, respectively. Stepwise multiple regression analysis revealed that younger age (p = 0.01), female sex (p = 0.01), and number of fused segments (p = 0.02) were significantly associated with higher HBL. Conclusions: The HBL in OLIF was 797 mL, which was more than other previously reported procedures. Therefore, OLIF may not be less invasive in terms of HBL. Blood loss after surgery should be considered, especially when patients are younger, are female, and have a greater number of fused segments.
The Impact of Mineral Supplementation on Polycystic Ovarian Syndrome
Authors: ElObeid Tahra , Awad Marwa Osman , Ganji Vijay , Moawad Joyce
Published: April 2022

Polycystic ovary syndrome (PCOS) is an endocrinopathy that is common among women of reproductive age. It is a heterogeneous disorder with an unknown etiology. Different strategies have been proposed for the treatment of PCOS. Recent studies recommend supplementation with specific minerals for treating various PCOS phenotypes. We searched PubMed, Google Scholar, and SCOPUS databases by using search terms combining PCOS with the supplementation of magnesium, zinc, selenium, or chromium. This review presents a narrative concerning the association between PCOS and magnesium, zinc, selenium, and chromium supplementation. We review findings from various randomized controlled trials and meta-analyses conducted in women of childbearing age with PCOS. Recent reports highlight the beneficial effect of minerals on the clinical and metabolic symptoms of PCOS. Further studies are required to establish the appropriate dosage level of these minerals for ameliorating the pathologies associated with PCOS because of the potential health risks linked with higher doses.
Self-Calibration Technique with Lightweight Algorithm for Thermal Drift Compensation in MEMS Accelerometers
Authors: Martínez Javier , Asiain David , Beltrán José Ramón
Published: April 2022

Capacitive MEMS accelerometers have a high thermal sensitivity that drifts the output when subjected to changes in temperature. To improve their performance in applications with thermal variations, it is necessary to compensate for these effects. These drifts can be compensated using a lightweight algorithm by knowing the characteristic thermal parameters of the accelerometer (Temperature Drift of Bias and Temperature Drift of Scale Factor). These parameters vary in each accelerometer and axis, making an individual calibration necessary. In this work, a simple and fast calibration method that allows the characteristic parameters of the three axes to be obtained simultaneously through a single test is proposed. This method is based on the study of two specific orientations, each at two temperatures. By means of the suitable selection of the orientations and the temperature points, the data obtained can be extrapolated to the entire working range of the accelerometer. Only a mechanical anchor and a heat source are required to perform the calibration. This technique can be scaled to calibrate multiple accelerometers simultaneously. A lightweight algorithm is used to analyze the test data and obtain the compensation parameters. This algorithm stores only the most relevant data, reducing memory and computing power requirements. This allows it to be run in real time on a low-cost microcontroller during testing to obtain compensation parameters immediately. This method is aimed at mass factory calibration, where individual calibration with traditional methods may not be an adequate option. The proposed method has been compared with a traditional calibration using a six tests in orthogonal directions and a thermal chamber with a relative error difference of 0.3%.
Development of an Electromagnetic Micromanipulator Levitation System for Metal Additive Manufacturing Applications
Authors: Kumar Parichit , Malik Saksham , Toyserkani Ehsan , Khamesee Mir
Published: April 2022

Magnetism and magnetic levitation has found significant interest within the field of micromanipulation of objects. Additive manufacturing (AM), which is the computer-controlled process for creating 3D objects through the deposition of materials, has also been relevant within the academic environment. Despite the research conducted individually within the two fields, there has been minimal overlapping research. The non-contact nature of magnetic micromanipulator levitation systems makes it a prime candidate within AM environments. The feasibility of integrating magnetic micromanipulator levitation system, which includes two concentric coils embedded within a high permeability material and carrying currents in opposite directions, for additive manufacturing applications is presented in this article. The working principle, the optimization and relevant design decisions pertaining to the micromanipulator levitation system are discussed. The optimized dimensions of the system allow for 920 turns in the inner coil and 800 turns in the outer coil resulting in a Ninnercoil:Noutercoil ratio of 1.15. Use of principles of free levitation, which is production of levitation and restoration forces with the coils, to levitate non-magnetic conductive materials with compatibility and applications within the AM environment are discussed. The Magnetomotive Force (MMF) ratio of the coils are adjusted by incorporation of an resistor in parallel to the outer coil to facilitate sufficient levitation forces in the axial axis while producing satisfactory restoration forces in the lateral axes resulting in the levitation of an aluminum disc with a levitation height of 4.5 mm. An additional payload of up to 15.2 g (59% of mass of levitated disc) was added to a levitated aluminum disk of 26 g showing the system capability coping with payload variations, which is crucial in AM process to gradually deploy masses. The final envisioned system is expected to have positional stability within the tolerance range of a few μm. The system performance is verified through the use of simulations (ANSYS Maxwell) and experimental analyses. A novel method of using the ratio of conductivity (σ) of the material to density (ρ) of the material to determine the compatibility of the levitation ability of non-magnetic materials with magnetic levitation application is also formulated. The key advantage of this method is that it does not rely on experimental analyses to determine the levitation ability of materials.
Blood-Meal Sources and Trypanosoma cruzi Infection in Coastal and Insular Triatomine Bugs from the Atacama Desert of Chile
Authors: Quiroga Nicol , Correa Juana P. , Campos-Soto Ricardo , San Juan Esteban , Araya-Donoso Raúl , Díaz-Campusano Gabriel , González Christian R. , Botto-Mahan Carezza
Published: April 2022

Mepraia parapatrica is one of the lesser known and less abundant sylvatic triatomine species naturally infected by the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease. M. parapatrica lives in sympatry with T. cruzi-infected rodents, but only birds, reptiles, and marine mammals have been reported as blood-meal sources of this vector species by serology. The distribution range of this kissing bug overlaps with fishers’ settlements and tourist areas, and therefore the study of the blood-meal sources of this triatomine species is relevant. Here, we determined the blood-meal sources of M. parapatrica by NGS or standard sequencing from a coastal mainland area and an island in northern Chile, and T. cruzi infection by real-time PCR. The blood-meals of. M parapatrica included 61.3% reptiles, 35.5% mammals (including humans) and 3.2% birds. Feeding on reptiles was more frequent on the mainland, while on the island feeding on mammals was more frequent. The presence of T. cruzi-infected triatomine bugs and humans as part of the diet of M. parapatrica in both areas represents an epidemiological threat and potential risk to the human population visiting or established in these areas. Currently there are no tools to control wild triatomines; these results highlight the potential risk of inhabiting these areas and the necessity of developing information campaigns for the community and surveillance actions.
Effects of LAB Inoculants on the Fermentation Quality, Chemical Composition, and Bacterial Community of Oat Silage on the Qinghai-Tibetan Plateau
Authors: Cheng Qiming , Chen Liangyin , Chen Yulian , Li Ping , Chen Chao
Published: April 2022

Lactic acid bacteria (LAB) have been proposed for the control of undesirable fermentation and, subsequently, aerobic deterioration due to their ability to produce antimicrobial metabolites in silage mass. To investigate the effect of specific LAB on the silage fermentation characteristics and bacterial community composition of oat in cold regions, silages were treated without (control) or with three LAB strains (LB, Lentilactobacillus buchneri; nLP, low temperature tolerant Lactiplantibacillus plantarum; pLP, phenyllactic acid-producing Lactiplantibacillus plantarum), and then stored at ambient temperature (−2.63 ± 5.47–14.29 ± 5.48 °C) for 30, 60, and 90 days. Compared with control, inoculation of LAB decreased the final pH value, butyric acid content, ammonia-N of total N and dry matter loss of silage. Treatments with nLP and pLP increased (p < 0.05) lactic acid content, whereas LB increased (p < 0.05) acetic acid content of silage. Lactiplantibacillus and Leuconostoc dominated in the silages with relative abundance of 68.29–96.63%. A prolonged storage period enhanced the growth of Leuconostoc in pLP-treated silage. In addition, pLP increased (p < 0.05) the aerobic stability of silage as compared with nLP. In conclusion, inoculation of LAB improved silage fermentation and/or delayed aerobic deterioration by shifting bacterial community composition during ensiling. Phenyllactic acid-producing Lactiplantibacillusplantarum as an inoculant exhibited potential for high quality silage production.
Anti-Melanogenic and Antioxidant Effects of Cell-Free Supernatant from Lactobacillus gasseri BNR17
Authors: Lee Sol , Park Han-Oh , Yoo Wonbeak
Published: April 2022

In recent years, there has been considerable interest in the use of cell-free supernatant of probiotics culture for nutritional and functional applications. In this study, we investigated the effect of the cell-free supernatant from Lactobacillus gasseri BNR17 (CFS) on anti-melanogenesis and reducing oxidative stress in B16-F10 murine melanoma cells and HaCaT human keratinocytes. Treatment with CFS significantly inhibited the production of extracellular and intracellular melanin without cytotoxicity during melanogenesis induced by the α-MSH in B16-F10 cells. The CFS dramatically reduced tyrosinase activity and the melanogenesis-related gene expression. Further, it showed antioxidative effects in a dose-dependent manner in DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) assays and significantly increased the mRNA levels of HO-1 and CAT in HaCaT cells. Furthermore, the CFS increased HO-1 and anti-oxidative-related gene expression during H2O2-induced oxidative stress in HaCaT cells. Together, this study suggests that the CFS reduces hyperpigmentation and inhibits oxidative stress, and thus can be used as a potential skincare product in the future.
Biomimetic Synthesis of Silver Nanoparticles Using Ethyl Acetate Extract of Urtica diocia Leaves; Characterizations and Emerging Antimicrobial Activity
Authors: Binsalah Mohammed , Devanesan Sandhanasamy , AlSalhi Mohamad S. , Nooh Abdullrahman , Alghamdi Osama , Nooh Nasser
Published: April 2022

The current work reports the biosynthesis of silver nanoparticles (AgNPs) using the antimicrobial activities of ethyl acetate extract of Urtica diocia (UD) leaves as a reducing and capping agent. The synthesized UD-AgNPs were characterized using UV–visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDAX), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and dynamic light scattering (DLS). The UD-AgNPs were evaluated against Gram-positive and Gram-negative bacteria, and their size, shape, and distribution were recorded. The average size of an NP was 19.401 nm. The zone of inhibition (ZOI) for 75 µL of UD-AgNPs against Pseudomonas aeruginosa (P. aeruginosa) was 21 ± 0.4 mm more than that of the control drug Ciprofloxacin (16 ± 10 mm). The minimum inhibitory concentration (MIC) was the lowest against Escherichia coli (E. coli) (36 ± 3 µg/mL) and Staphylococcusepidermidis (S. epidermidis) (38 ± 3 µg/mL). Moreover, the minimum bactericidal concentration (MBC) was the lowest against E.coli (75 ± 00 µg/mL) and Enterococcus faecalis (E. faecalis (83 ± 16 µg/mL). Thus, the UD-AgNPs synthesized using the ethyl acetate extract of UD can be used as a new antimicrobial drug.
Could Pontimonas Harbour Halophilic Members Able to Withstand Very Broad Salinity Variations?
Authors: Gorrasi Susanna , Pasqualetti Marcella , Braconcini Martina , Muñoz-Palazon Barbara , Fenice Massimiliano
Published: April 2022

Pontimonas is currently described as a genus including only one species of slightly halophilic marine bacteria. Although some works revealed its presence in some hypersaline environments, the information on its habitat preference is still scant. This work investigated Pontimonas presence in selected ponds of the Saline di Tarquinia marine saltern and in the seawater intake area. The two-year metabarcoding survey documented its constant presence along the ponds establishing the salinity gradient and in a distinct basin with permanent hypersaline conditions (BSB). Pontimonas was higher in the ponds than in the sea, whereas it had similar abundances in the sea and in the BSB. Its representative OTUs showed significant trends according to different parameters. Along the salinity gradient, OTU1 abundance increased with decreasing water temperatures and increasing rainfalls, and it showed a maximum in January; OTU2 increased with increasing BOD5 and it showed the highest abundances in the period August–October, and OTU 3194 increased at decreasing salinities. In BSB, a significant seasonal variation was shown by OTU 3194, which started increasing in spring to reach a maximum in summer. The results suggest that Pontimonas could easily settle in hypersaline habitats, having also broad euryhaline members and some possible extreme halophilic representatives.
The Transcription of Flagella of Enteropathogenic Escherichia coli O127:H6 Is Activated in Response to Environmental and Nutritional Signals
Authors: Avelino-Flores Fabiola , Soria-Bustos Jorge , Saldaña-Ahuactzi Zeus , Martínez-Laguna Ygnacio , Yañez-Santos Jorge A. , Cedillo-Ramírez María L. , Girón Jorge A.
Published: April 2022

The flagella of enteropathogenic Escherichia coli (EPEC) O127:H6 E2348/69 mediate adherence to host proteins and epithelial cells. What environmental and nutritional signals trigger or down-regulate flagella expression in EPEC are largely unknown. In this study, we analyzed the influence of pH, oxygen tension, cationic and anionic salts (including bile salt), carbon and nitrogen sources, and catecholamines on the expression of the flagellin gene (fliC) of E2348/69. We found that sodium bicarbonate, which has been shown to induce the expression of type III secretion effectors, down-regulated flagella expression, explaining why E2348/69 shows reduced motility and flagellation when growing in Dulbecco’s Minimal Essential Medium (DMEM). Further, growth under a 5% carbon dioxide atmosphere, in DMEM adjusted to pH 8.2, in M9 minimal medium supplemented with 80 mM glucose or sucrose, and in DMEM containing 150 mM sodium chloride, 0.1% sodium deoxycholate, or 30 µM epinephrine significantly enhanced fliC transcription to different levels in comparison to growth in DMEM alone. When EPEC was grown in the presence of HeLa cells or in supernatants of cultured HeLa cells, high levels (4-fold increase) of fliC transcription were detected in comparison to growth in DMEM alone. Our data suggest that nutritional and host signals that EPEC may encounter in the intestinal niche activate fliC expression in order to favor motility and host colonization.
Interaction of Bdellovibrio bacteriovorus with Gram-Negative and Gram-Positive Bacteria in Dual Species and Polymicrobial Communities
Authors: Waso-Reyneke Monique , Khan Sehaam , Khan Wesaal
Published: April 2022

The interaction of Bdellovibrio bacteriovorus PF13 with mixed bacterial communities, consisting of Gram-negative (Pseudomonas fluorescens and Klebsiella pneumoniae) and Gram-positive (Staphylococcus aureus and Enterococcus faecium) bacteria, was investigated to determine if this wild-type predator preferentially preys on certain bacteria and whether the presence of Gram-positive organisms influences its predation efficiency. In co-culture with P. fluorescens and K. pneumoniae, the cell counts (PFU/mL) of PF13 increased by 5.79 and 5.17 logs (48 h), respectively, while in the dual species assay (P. fluorescens, K. pneumoniae and PF13), the cell counts of PF13 increased by 1.95 logs (24 h). Using ethidium monoazide bromide quantitative polymerase chain reaction (EMA-qPCR), the concentration of PF13 increased by 1.25 to 3.62 logs in the co-culture experiments, by 1.41 to 5.05 logs in dual species cultures and by 2.65 logs in a polymicrobial culture. However, PF13 preferentially preyed on K. pneumoniae in the dual species and polymicrobial cultures, highlighting that the presence of Gram-positive bacteria did not affect the predation efficiency of PF13. This is significant as it implies that the predator can be applied in mixed microbial communities to target Gram-negative pathogens which may pose a health risk to patients, consumers or for the treatment of contaminated water.
Yeasts Inhabiting Extreme Environments and Their Biotechnological Applications
Authors: Segal-Kischinevzky Claudia , Romero-Aguilar Lucero , Alcaraz Luis D. , López-Ortiz Geovani , Martínez-Castillo Blanca , Torres-Ramírez Nayeli , Sandoval Georgina , González James
Published: April 2022

Yeasts are microscopic fungi inhabiting all Earth environments, including those inhospitable for most life forms, considered extreme environments. According to their habitats, yeasts could be extremotolerant or extremophiles. Some are polyextremophiles, depending on their growth capacity, tolerance, and survival in the face of their habitat’s physical and chemical constitution. The extreme yeasts are relevant for the industrial production of value-added compounds, such as biofuels, lipids, carotenoids, recombinant proteins, enzymes, among others. This review calls attention to the importance of yeasts inhabiting extreme environments, including metabolic and adaptive aspects to tolerate conditions of cold, heat, water availability, pH, salinity, osmolarity, UV radiation, and metal toxicity, which are relevant for biotechnological applications. We explore the habitats of extreme yeasts, highlighting key species, physiology, adaptations, and molecular identification. Finally, we summarize several findings related to the industrially-important extremophilic yeasts and describe current trends in biotechnological applications that will impact the bioeconomy.
Molecular and Physiological Properties of Indigenous Strains of Oenococcus oeni Selected from Nero di Troia Wine (Apulia, Italy)
Authors: Cappello Maria Stella , Falco Vittorio , Curcio Rosita , Mita Giovanni , Zapparoli Giacomo
Published: April 2022

The characterization of Oenococcus oeni strains isolated from Nero di Troia wine (Apulia, Italy) sampled in two distinct production areas was carried out. The two indigenous populations, consisting of 95 and 97 isolates, displayed high genetic diversity when analyzed by amplified fragments length polymorphisms (AFLP). Based on the UPGMA dendrogram obtained by AFLP analysis, the two populations displayed similar genotypes that grouped in the same clusters with a high level of similarity (>95%). One genotype was found in only one of the two areas. Representative strains of each cluster were analyzed for their enzymatic activities (esterase, β-glucosidase, and protease), assayed in whole cells, and tested for their metabolic properties (consumption of L-malic acid, citric acid, acetaldehyde, and arginine) and growth parameters. Significant differences among strains, including the reference strain ATCC BAA-1163, were observed for all of these properties. Principal component analysis evidenced phenotypic differences among strains, and well separated some of them belonging to different genotypes. Strains exhibiting the best performances in most of these traits could be further investigated in order to select possible candidates as malolactic starters for Nero di Troia wine. This study provided insights on the population structure of O. oeni of a local winemaking area useful to the understanding of the regional diversity of this bacterium, an issue not yet completely resolved
Raman Spectroscopy Analysis of the Mural Pigments in Lam Rim Hall of Wudang Lamasery, Baotou Area, Inner Mongolia, China
Authors: Zheng Yi-Xuan , He Xiang , Li Xin , Chen Kun-Long , Guo Hong , Pan Xiao-Xuan
Published: April 2022

This paper presents scientific analyses of the wall paintings in Wudang Lamasery, which is located in the Baotou area of Inner Mongolia, China. Raman spectroscopy was used to analyze the pigments of the mural of the Lam rim Hall. The results show that vermilion, red lead, chrome yellow, emerald green and synthetic ultramarine were used. The existence of synthetic pigments provides a clue for the date the mural was painted.
Mineralogical Characteristic and Beneficiation Evaluation of a Ta-Nb-Li-Rb Deposit
Authors: Lv Zihu , Cheng Hongwei , Wei Min , Zhao Dengkui , Wu Dongyin , Liu Changmiao
Published: April 2022

In order to rationally develop and utilize a Ta–Nb–Li–Rb rare metal deposit in Jiangxi Province, the mineralogical characteristics of the ore, such as chemical composition, mineral composition, modes of occurrence of major elements, and dissemination characteristics of major minerals, were investigated in detail based on optical microscopy analysis, chemical analysis, X-ray diffraction analysis, artificial panning, mineral liberation analysis, and electron probe microanalysis. The results reveal that the main useful elements in the ore are tantalum, niobium, lithium, and rubidium. Niobium and tantalum are mainly found in the mineral form of columbite. Columbite has particle sizes ranging from 0.5 mm to 0.012 mm, with the most common sizes being 0.3 to 0.044 mm. Intergranular dispersion accounts for 73.92% of the embedding in columbite, whereas inclusions account for 26.08%. Lithium is found mostly in zinnwaldite, while rubidium is found primarily in feldspar and zinnwaldite, both in a homogenous distribution. The beneficiation evaluation of this ore was conducted based on the mineralogical characteristic, and it indicates that the tantalum-niobium–lithium–rubidium rare metal resources, as well as the feldspar and quartz non-metallic resources in the ore, can be effectively and comprehensively recovered using gravity, magnetic, and flotation separation methods. A staged grinding and separating process was adopted which could produce tantalum–niobium mineral concentrates (18.34% Ta2O5 at a recovery of 47.65% and 41.33% Nb2O5 at a recovery of 69.96%), zinnwaldite concentrate (2.41% Li2O and 0.80% Rb2O at a recovery of 81.82%) and other concentrates such as cassiterite, topaz, galena, sphalerite, and feldspar. This study provides suggestions for the rational development and utilization of the deposit and provides a reasonable level of recovery prediction.
Preparation and Swelling Inhibition of Mixed Metal Hydroxide to Bentonite Clay
Authors: Zhang Bowen , Wang Qingchen , Wei Yan , Wei Wei , Du Weichao , Zhang Jie , Chen Gang , Slaný Michal
Published: April 2022

In this paper, mixed metal hydroxide (MMH) was prepared via MgCl2 and AlCl3 by the co-precipitation method and characterized by XRD, TGA laser and particle size analysis. The inhibitory effect of MMH on the swelling of clay was evaluated by linear expansion, mud ball, laser particle size analysis, X-ray diffraction analysis and TGA. The linear expansion experiment showed that MMH with a ratio of Mg:Al = 3:1 displayed a strong inhibitory effect on bentonite expansion when 0.3% MMH was added to the drilling fluid, demonstrating better inhibition than 4.0% KCl. Within 48 h, only a few cracks were visible on the mud ball surface in the 0.3% MMH suspension, which indicates that MMH can inhibit wet bentonite for deep hydration. X-ray diffraction and particle size analyses of bentonite were conducted before and after MMH was added to illustrate the inhibition. MMH also displayed high temperature resistance in water-based drilling fluid as a shear strength-improving agent, and its dynamic plastic ratio and shear force were stable after aging at 200 °C for 16 h.
Exploring Short and Efficient Synthetic Routes Using Titanocene(III)-Catalyzed Reactions: Total Synthesis of Natural Meroterpenes with Trisubstituted Unsaturations
Authors: Rosales Jennifer , Cabrera Gustavo , Justicia José
Published: April 2022

The stereo- and regioselective total syntheses of OMe derivatives of the scarce bioactive meroterpenoids makassaric acid (1) and fascioquinol B (2) have been accomplished. The synthetic sequences are based on the following three efficient and selective catalytic reactions: Cu-catalyzed addition of Grignard compounds to an epoxide; a regioselective Barbier-type reaction, catalyzed by Cp2TiCl; and regio- and stereoselective bioinspired cyclization, also catalyzed by Cp2TiCl. These three key processes allow us to obtain the main skeletons of 1 and 2 in a few steps. The valuable synthetic proposal shown in this work provides fast access to scarce, structurally complex meroterpenes with promising biological activities, which are a sustainable source for later studies and applications in medicine.