bluuebunny/crossref_metadata_2025 huggingface dataset:
A Distance-Weighted Dynamic Bandwidth Allocation Algorithm for Improved Performance in Long-Reach Passive Optical Networks for Next Generation Networks
Authors: Haastrup Adebanjo , Zehri Mohammad , Rincón David , Piney José Ramón , Bazzi Ali
Published: August 2023

In recent years, there has been an increasing trend towards extending the coverage of passive optical networks (PONs) over large geographical areas. Long-reach PONs (LRPONs) are capable of extending the distance covered by PONs from 20 km to 100 km, leading to cost savings in the network operation by reducing the number of central offices. They have become widely deployed due to their ability to provide high-speed, long-distance data transmission over optical fibers. In addition, the next generation of optical access networks are expected to provide high-capacity mobile and wireless backhauling over a wide coverage area. However, this extended reach also requires the design of efficient dynamic bandwidth allocation (DBA) schemes to address the performance degradation caused by the increased propagation delay in LRPONs. The DBA schemes commonly used for upstream traffic transmission in traditional PONs are not well-suited for use in LRPONs due to their inefficiency in bandwidth utilization due to the increased round-trip time (RTT) between the optical line terminal (OLT) and the optical network unit (ONU). In this study, we present an efficient DBA algorithm, the Distance-Weighted Bandwidth Allocation DWDBA Algorithm, specifically enhanced for multi-wavelength LRPONs. Our DBA algorithm utilizes a scheduling policy that assigns weight vectors to Optical Network Units (ONUs) based on their distance from the Optical Line Terminal (OLT), sorting them accordingly without penalizing any ONU due to their distance. The DWDBA takes the laser tuning time into consideration. We conducted extensive simulations to evaluate the performance of the proposed algorithm under various scenarios and compared it to the IPACT algorithm. The results of the simulations show that the proposed algorithm outperformed the IPACT algorithm in terms of bandwidth utilization and queue delay.
Chlorophyll Content and Photosynthetic Activity of Phytoplankton in Reservoirs of the Volga River (Russia)
Authors: Mineeva Natalya , Semadeni Ivan
Published: August 2023

Using the fluorescent method in the modification of Krasnoyarsk State University, we studied the development (as chlorophyll content, ∑CHL) and photosynthetic activity of phytoplankton in seven large flat reservoirs of the Volga River cascade (Russia) in August 2015–2017. In the period of the maximal warming of water, average ∑CHL varied in limits of 19.4–33.7 μg L−1 in the Upper Volga, 8.5–27.8 μg L−1 in the Middle Volga, and 5.2–11.3 μg L−1 in the Lower Volga. The photosynthetic activity coefficient (PhAC) varied mostly in limits of 0.12–0.59, with an average of 0.22–0.38 and only in 2017 decreased to minimal < 0.10 and average < 0.20. The average PhAC values show the normal physiological state of the phytoplankton of the Upper Volga during all periods of observation, with an occasional decrease in PhAC in the Middle Volga and low photosynthetic activity in the Lower Volga. A decrease in the average ∑Chl and PhAC in 2017 was under cyclonic windy weather with a large amount of precipitation, low solar radiation, and large volume of flow. A trend towards a decrease in ∑CHL, like a decrease in PhAC from the Upper Volga to the Lower Volga, is explained by an increase in the flow rate and volume of runoff downstream of the Volga River.
Faculty Hiring Network Reveals Possible Decision-Making Mechanism
Authors: Zheng Sunjing , Jiang Nan , Li Xiaomeng , Xiao Mingzhong , Chen Qinghua
Published: August 2023

Social physics (or sociophysics) offers new research perspectives for addressing social issues in various domains. In this study, we explore the decision-making process of doctoral graduates during their transition from graduation to employment, drawing on the ideas of sociophysics. We divide the process into two decision steps and propose a generative model based on appropriate assumptions. This model effectively reproduces empirical data, allowing us to derive essential parameters that influence the decision-making process from empirical observations. Through a comparison of the best-fit parameters, we discover that doctoral graduates in business disciplines tend to exhibit more concentrated employment choices, while those in computer science and history disciplines demonstrate a greater diversity of options. Furthermore, we observe that universities consider factors beyond rankings when selecting doctoral graduates.
Phytochemical Properties of Croton gratissimus Burch (Lavender Croton) Herbal Tea and Its Protective Effect against Iron-Induced Oxidative Hepatic Injury
Authors: Ncume Paul V. , Salau Veronica F. , Mtshali Sibahle , Olofinsan Kolawole A. , Erukainure Ochuko L. , Matsabisa Motlalepula G.
Published: August 2023

Oxidative stress plays a vital role in the pathogenesis and progression of various liver diseases. Traditional medicinal herbs have been used worldwide for the treatment of chronic liver diseases due to their high phytochemical constituents. The present study investigated the phytochemical properties of Croton gratissimus (lavender croton) leaf herbal tea and its hepatoprotective effect on oxidative injury in Chang liver cells, using an in vitro and in silico approach. C. gratissimus herbal infusion was screened for total phenolic and total flavonoid contents as well as in vitro antioxidant capacity using ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picryl-hydrazyl (DPPH) methods. Oxidative hepatic injury was induced by incubating 0.007 M FeSO4 with Chang liver cells which has been initially incubated with or without different concentrations (15–240 μg/mL) of C. gratissimus infusion or the standard antioxidants (Gallic acid and ascorbic acid). C. gratissimus displayed significantly high scavenging activity and ferric reducing capacity following DPPH and FRAP assays, respectively. It had no cytotoxic effect on Chang liver cells. C. gratissimus also significantly elevated the level of hepatic reduced glutathione (GSH), superoxide dismutase (SOD), and catalase activities as well as suppressed the malondialdehyde (MDA) level in oxidative hepatic injury. Liquid Chromatography–Mass Spectrometry (LC-MS) analysis of the herbal tea revealed the presence of 8-prenylnaringenin, flavonol 3-O-D-galactoside, caffeine, spirasine I, hypericin, pheophorbide-a, and 4-methylumbelliferone glucuronide. In silico oral toxicity prediction of the identified phytochemicals revealed no potential hepatotoxicity. Molecular docking revealed potent molecular interactions of the phytochemicals with SOD and catalase. The results suggest the hepatoprotective and antioxidative potentials of C. gratissimus herbal tea against oxidative hepatic injury.
Plant Essential Oils as Biopesticides: Applications, Mechanisms, Innovations, and Constraints
Authors: Gupta Ipsa , Singh Rishikesh , Muthusamy Suganthi , Sharma Mansi , Grewal Kamaljit , Singh Harminder Pal , Batish Daizy R.
Published: August 2023

The advent of the “Green Revolution” was a great success in significantly increasing crop productivity. However, it involved high ecological costs in terms of excessive use of synthetic agrochemicals, raising concerns about agricultural sustainability. Indiscriminate use of synthetic pesticides resulted in environmental degradation, the development of pest resistance, and possible dangers to a variety of nontarget species (including plants, animals, and humans). Thus, a sustainable approach necessitates the exploration of viable ecofriendly alternatives. Plant-based biopesticides are attracting considerable attention in this context due to their target specificity, ecofriendliness, biodegradability, and safety for humans and other life forms. Among all the relevant biopesticides, plant essential oils (PEOs) or their active components are being widely explored against weeds, pests, and microorganisms. This review aims to collate the information related to the expansion and advancement in research and technology on the applications of PEOs as biopesticides. An insight into the mechanism of action of PEO-based bioherbicides, bioinsecticides, and biofungicides is also provided. With the aid of bibliometric analysis, it was found that ~75% of the documents on PEOs having biopesticidal potential were published in the last five years, with an annual growth rate of 20.51% and a citation per document of 20.91. Research on the biopesticidal properties of PEOs is receiving adequate attention from European (Italy and Spain), Asian (China, India, Iran, and Saudi Arabia), and American (Argentina, Brazil, and the United States of America) nations. Despite the increasing biopesticidal applications of PEOs and their widespread acceptance by governments, they face many challenges due to their inherent nature (lipophilicity and high volatility), production costs, and manufacturing constraints. To overcome these limitations, the incorporation of emerging innovations like the nanoencapsulation of PEOs, bioinformatics, and RNA-Seq in biopesticide development has been proposed. With these novel technological interventions, PEO-based biopesticides have the potential to be used for sustainable pest management in the future.
Biochemical and Phylogenetic Analysis of Italian Phaseolus vulgaris Cultivars as Sources of α-Amylase and α-Glucosidase Inhibitors
Authors: Peddio Stefania , Lorrai Sonia , Padiglia Alessandra , Cannea Faustina B. , Dettori Tinuccia , Cristiglio Viviana , Genovese Luigi , Zucca Paolo , Rescigno Antonio
Published: August 2023

Phaseolus vulgaris α-amylase inhibitor (α-AI) is a protein that has recently gained commercial interest, as it inhibits mammalian α-amylase activity, reducing the absorption of dietary carbohydrates. Numerous studies have reported the efficacy of preparations based on this protein on the control of glycaemic peaks in type-2 diabetes patients and in overweight subjects. A positive influence on microbiota regulation has also been described. In this work, ten insufficiently studied Italian P. vulgaris cultivars were screened for α-amylase- and α-glucosidase-inhibiting activity, as well as for the absence of antinutritional compounds, such as phytohemagglutinin (PHA). All the cultivars presented α-glucosidase-inhibitor activity, while α-AI was missing in two of them. Only the Nieddone cultivar (ACC177) had no haemagglutination activity. In addition, the partial nucleotide sequence of the α-AI gene was identified with the degenerate hybrid oligonucleotide primer (CODEHOP) strategy to identify genetic variability, possibly linked to functional α-AI differences, expression of the α-AI gene, and phylogenetic relationships. Molecular studies showed that α-AI was expressed in all the cultivars, and a close similarity between the Pisu Grogu and Fasolu cultivars’ α-AI and α-AI-4 isoform emerged from the comparison of the partially reconstructed primary structures. Moreover, mechanistic models revealed the interaction network that connects α-AI with the α-amylase enzyme characterized by two interaction hotspots (Asp38 and Tyr186), providing some insights for the analysis of the α-AI primary structure from the different cultivars, particularly regarding the structure–activity relationship. This study can broaden the knowledge about this class of proteins, fuelling the valorisation of Italian agronomic biodiversity through the development of commercial preparations from legume cultivars.
Age Determination and Growth Characteristics of the Potentilla griffithii: A Comparison of Two Different Habitats in Western Sichuan Plateau, China
Authors: Zhang Xiulong , Lin Xingxing , Wei Dandan , Bao Weikai , Hu Bin
Published: August 2023

This study proposes a rapid and non-destructive technique for determining the age of Potentilla griffithii individuals in the field by observing the sequence of leaf scars. Based on two- to three-year-old P. griffithii seedlings, planted in a common garden in the western Sichuan Plateau, China, the study found that the rates of basal leaf production were consistent, with leaves growing from March to April and falling off from October to December, leaving behind basal leaf scars. Thus, the age of individuals in situ could be determined by counting the leaf scars. Through this method, we determined the age structure and growth strategy of P. griffithii populations in two typical habitats in the western Sichuan Plateau. In open land habitats, the age structure of P. griffithii populations was relatively younger compared to understory habitats. In open land, P. griffithii tends to allocate more photosynthate terminal organs (leaves and fine roots) to absorbing more resources, as well as to its reproductive organs (flower stems and aggregate fruits), to expand the population. The P. griffithii population in the understory habitat is in its middle-age stage and concentrates more photosynthate in the coarse root part (e.g., the high coarse root mass fraction (FRMF)) to support the plant. Additionally, we found a significant correlation between P. griffithii plant age and various traits in open land habitats. Therefore, we conclude that plant age can be used as a good predictor of plant growth condition in open land. These results allow for predicting ecological processes, based on the ages and traits of P. griffithii plants, providing a theoretical basis to support the large-scale breeding of P. griffithii.
Different Weed Managements Influence the Seasonal Floristic Composition in a Super High-Density Olive Orchard
Authors: Popolizio Stefano , Vivaldi Gaetano Alessandro , Camposeo Salvatore
Published: August 2023

Weed management is not yet environmentally, agronomically, economically and socially sustainable in olive orchards. It is necessary to study appropriate integrated weed management systems (IWMSs) based on the knowledge of weed population and effects of weeding practices over time. The aim of this study was to evaluate the effects of different weed managements on seasonal floristic composition of a super high-density olive orchard, also exploiting the essential principles of an IWMS. Five weeding techniques were compared: chemical control (CHI), mowing (MEC), plastic (nonwoven tissue, TNT and polyethylene, PEN) and organic (with de-oiled olive pomace, DOP) mulching. Weed monitoring was carried out on six dates in a three-year period. The infestation of each of the main 18 weed species recorded (%) and the total infestation (%) on each monitoring date were determined. Results underlined that all weeding practices investigated in this multi-year study affected the floristic composition, weed characteristics (hemicryptophytes, cryptophytes and therophytes) and seed bank. TNT and PEN were the most effective methods for weed management. Particularly, total infestation coefficient was significantly lowest when plots were managed with TNT (13.91%) and PEN (14.38%) and highest for MEC (141.29%). However, DOP also significantly reduced infestation compared to CHI and MEC. Therefore, DOP could constitute an excellent strategy for weed management in super high-density olive groves, since it also has the possibility of distributing mulching materials in a mechanized way in field and can result in improvement of soil fertility and the possibility of valorizing waste. Further studies should be carried out to investigate the mechanism of action (physical and allelochemical) of de-oiled pomace or other organic agro-industrial materials and the recovery time of these mulching materials in super high-density olive orchards.
Efficacy of Carbon Nanodots and Manganese Ferrite (MnFe2O4) Nanoparticles in Stimulating Growth and Antioxidant Activity in Drought-Stressed Maize Inbred Lines
Authors: Ilyas Muhammad Zahaib , Park Hyeon , Baek Young Sun , Sa Kyu Jin , Kim Myong Jo , Lee Ju Kyong
Published: August 2023

Despite being the third most-consumed crop, maize (Zea mays L.) is highly vulnerable to drought stress. The predominant secondary metabolite in plants is phenolic acids, which scavenge reactive oxygen species to minimize oxidative stress under drought stress. Herein, the effect of carbon nanodots (CND) and manganese ferrite (MnFe2O4) nanoparticles (NP) on the drought stress tolerance of maize has been studied. The experimental results revealed that the highest leaf blade length (54.0 cm) and width (3.9 cm), root length (45.2 cm), stem diameter (11.1 mm), root fresh weight (7.0 g), leaf relative water content (84.8%) and chlorogenic (8.7 µg/mL), caffeic (3.0 µg/mL) and syringic acid (1.0 µg/mL) contents were demonstrated by CND-treated (10 mg L−1) inbred lines (GP5, HW19, HCW2, 17YS6032, HCW3, HCW4, HW7, HCW2, and 16S8068-9, respectively). However, the highest shoot length (71.5 cm), leaf moisture content (83.9%), shoot fresh weight (12.5 g), chlorophyll content (47.3), and DPPH free radical scavenging activity (34.1%) were observed in MnFe2O4 NP-treated (300 mg L−1) HF12, HW15, 11BS8016-7, HW15, HW12, and KW7 lines, respectively. The results indicate that CND and MnFe2O4 NP can mitigate drought stress effects on different accessions of the given population, as corroborated by improvements in growth and physio-biochemical traits among several inbred lines of maize.
Plasma Energy Loss by Cathode Heat Conduction in a Vacuum Arc: Cathode Effective Voltage
Authors: Beilis Isak I.
Published: August 2023

The importance of understanding the energy loss specifics by the cathode for vacuum arc metallic plasma generation and its applications were emphasized. To this end, the heat conduction losses per unit current were characterized by the cathode effective voltage uef, which is weakly dependent on the current. In this paper, a physical model and a mathematical approach were developed to describe the energy dissipation due to heat conduction in the cathode body, which is heated by energy outflowed from the adjacent plasma. The arc plasma generation was considered by taking into account the kinetics of the heavy particle fluxes in the non-equilibrium layer near the vaporizing surface. The phenomena of electric sheath, heat and mass transfer at the cathode were taken into account. The self-consistent numerical analysis was performed with a system of equations for a copper cathode spot. The transient analysis starts from the spot initiation, modeled by the plasma arising at the initial time determined by the kind of arc triggering, up to spot development. The results of the calculations show that the cathode effective voltage uef is determined by the cathode temperature as a function of spot time. The calculated evolution of the voltage uef shows that the steady state of uef is approximately 7 V, and it is reached when the cathode temperature reaches a steady state at approximately one microsecond. This essential result provides an explanation for the good agreement with the experimental cathode effective voltage (6–8 V) measured for the arc duration from one millisecond up to a few seconds.
Optimization of Oil Sorbent Thermoplastic Elastomer Microfiber Production by Centrifugal Spinning
Authors: Kántor József , Farmos Rudolf László , Gergely Attila Levente
Published: August 2023

Fibrous structures are promising candidates for oil–water separation applications. In this study, we have produced poly(styrene-b-isobutylene-b-styrene) thermoplastic elastomeric fibers with the centrifugal spinning fiber production method. The optimal fiber production conditions were achieved when using a 25% w/w solution concentration in an 80/20 tetrahydrofuran/toluene (w/w) solvent system at 8000 rpm rotational speed. The produced fibers were bead-free and smooth-surfaced with a diameter of 3.68 µm. The produced fibers were highly hydrophobic and oleophilic, suggested by a water contact angle of 129° and the instantaneous absorption of the oil droplet. The oil absorption study showed fast absorption kinetics with 94% relative oil uptake after 1 min and a maximum of 16.5 g sunflower oil/g fiber. The results suggest that polyisobutylene-based thermoplastic elastomers could be promising alternatives in oil absorption applications.
Explicit Expressions for a Mean Nanofibre Diameter Using Input Parameters in the Process of Electrospinning
Authors: Filip Petr
Published: August 2023

The process of electrospinning is subject to a variety of input parameters ranging from the characterization of polymers and solvents, the resulting solutions, the geometrical configuration of the device, including its process parameters, and ending with crucial parameters such as temperature and humidity. It is not possible to expect that functional expressions relating all these parameters can be derived in a common description. Nevertheless, it is possible to fix the majority of these parameters to derive explicit relations for a restricted number of entry parameters such that it contributes to the partial elimination of the classical trial-and-error method saving time and financial costs. However, several contributions providing such results are rather moderate. Special attention is provided to fibre diameter approximation as this parameter strongly influences the application of nanofibrous mats in various instances such as air filtration, tissue engineering, and drug delivery systems. Various difficulties connected with the derivation of these explicit relations are presented and discussed in detail.
Facile Hydrothermal Synthesis of Ag/Fe3O4/Cellulose Nanocomposite as Highly Active Catalyst for 4-Nitrophenol and Organic Dye Reduction
Authors: Vu An Nang , Le Hoa Ngoc Thi , Phan Thang Bach , Le Hieu Van
Published: August 2023

Novel effluent treatment solutions for dangerous organic pollutants are crucial worldwide. In recent years, chemical reduction using noble metal-based nanocatalysts and NaBH4, a reducing agent, has become common practice for eliminating organic contaminants from aquatic environments. We suggest a straightforward approach to synthesizing magnetic cellulose nanocrystals (CNCs) modified with magnetite (Fe3O4) and silver nanoparticles (Ag NPs) as a catalyst for organic contamination removal. Significantly, the CNC surface was decorated with Ag NPs without using any reducing agents or stabilizers. PXRD, FE-SEM, TEM, EDX, VSM, BET, and zeta potential tests characterized the Ag/Fe3O4/CNC nanocomposite. The nanocomposite’s catalytic activity was tested by eliminating 4-nitrophenol (4-NP) and the organic dyes methylene blue (MB) and methyl orange (MO) in an aqueous solution at 25 °C. The Ag/Fe3O4/CNC nanocomposite reduced 4-NP and decolored these hazardous organic dyes in a short time (2 to 5 min) using a tiny amount of catalyst (2.5 mg for 4-NP and 15 mg for MO and MB). The magnetic catalyst was removed and reused three times without losing catalytic activity. This work shows that the Ag/Fe3O4/CNC nanocomposite can chemically reduce harmful pollutants in effluent for environmental applications.
Analysis of the Impact of Rubber Recyclate Addition to the Matrix on the Strength Properties of Epoxy–Glass Composites
Authors: Żuk Daria , Abramczyk Norbert , Charchalis Adam
Published: August 2023

Currently, there is a noticeable trend of modifying new materials by using additives from the recycling of harmful waste. This is to protect the environment by using waste to produce composites and at the same time to reduce the cost of their production. The article presents an analysis of the impact of the use of rubber recyclate obtained from the utilization of car tires as a sandwich layer of epoxy–glass composites and its impact on the strength parameters of the composite. The presented research is an extension of the previously conducted analyses on composite materials modified with the addition of rubber recyclate. The four variants of the materials produced contained the same percentage amount of rubber recyclate, but differed in the way it was distributed and the number of layers. Static tensile tests as well as impact strength and kinetics of damage to samples made with and without the addition of recyclate were carried out. Observation of the structures of the materials with the use of SEM was also performed. A significant influence of the method of distributing the recyclate in layers on the strength parameters of the materials was found. In the case of composites with three and two sandwich layers of recyclate, more favorable results were obtained compared to the blank sample. In addition, the values of the impact strength measurements were subjected to statistical analysis at the significance level of α = 95%. The distributions were tested for normality with the Shapiro–Wilk test, differences between pairs were tested with the Student’s t-test for dependent groups, and ANOVA differences were tested for independent groups. Using the Student’s t-test, it was confirmed that between the pairs of variables in the configurations reference sample and modified sample, there were significant statistical differences in the distribution of impact strength measurement results for all the analyzed materials. Statistical analysis showed a significant usefulness in the selection of the material with the best strength parameters and a significant role of statistical methods in the study of anisotropic materials.
Influence of Molecular Weight and Lithium Bis(trifluoromethanesulfonyl)imide on the Thermal Processability of Poly(ethylene oxide) for Solid-State Electrolytes
Authors: Platen Katharina , Langer Frederieke , Bayer Roland , Hollmann Robert , Schwenzel Julian , Busse Matthias
Published: August 2023

New energy systems such as all-solid-state battery (ASSB) technology are becoming increasingly important today. Recently, researchers have been investigating the transition from the lab-scale production of ASSB components to a larger scale. Poly(ethylene oxide) (PEO) is a promising candidate for the large-scale production of polymer-based solid electrolytes (SPEs) because it offers many processing options. Hence, in this work, the thermal processing route for a PEO-Lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) SPE in the ratio of 20:1 (EO:Li) is investigated using kneading experiments. Here, we clearly show the sensitivity of PEO during thermal processing, especially for high-molecular-weight PEO (Mw = 600,000 g mol−1). LiTFSI acts as a plasticizer for low-molecular-weight PEO (Mw = 100,000 g mol−1), while it amplifies the degradation of high-molecular-weight PEO. Further, LiTFSI affects the thermal properties of PEO and its crystallinity. This leads to a higher chain mobility in the polymer matrix, which improves the flowability. In addition, the spherulite size of the produced PEO electrolytes differs from the molecular weight. This work demonstrates that low-molecular-weight PEO is more suitable for thermal processing as a solid electrolyte due to the process stability. High-molecular-weight PEO, especially, is strongly influenced by the process settings and LiTFSI.
Analysis of the Stress Field in Photoelasticity Used to Evaluate the Residual Stresses of a Plastic Injection-Molded Part
Authors: Vargas-Isaza Carlos , Posada-Correa Juan , Briñez-de León Juan
Published: August 2023

The degree of quality of thermoplastic injection-molded parts can be established based on their weight, appearance, and defects. However, the conditions of the injection process may induce effects on the mechanical performance of the injected parts, and the residual stresses can cause cracks or early failures when an external load or force is applied. To evaluate these mechanical behaviors, different experimental techniques have been reported in the literature, where digital photoelasticity has stood out both for being a non-contact technique and for achieving quantitative results through sophisticated computational algorithms. Against this background, our proposal consists of analyzing the overall residual stress distribution of parts injected under different molding conditions by using digital photoelasticity. In this case, the specimens are subjected to bending strength tests to identify possible effects of the injection process conditions. The findings show that, at mold temperatures of 80 °C, flow-induced residual stresses increase with packing pressure. However, these internal stress levels do not affect the external load applied by the mechanical bending test, while the mass injected at higher levels of packing pressure helps to increase the bending strength of the injected part. At lower mold temperatures (50 °C), the mechanical strength of the injected part is slightly reduced, possibly due to a lower effect of the packing pressure.
Surface Modification of PP and PBT Nonwoven Membranes for Enhanced Efficiency in Photocatalytic MB Dye Removal and Antibacterial Activity
Authors: Aldebasi Shahad M. , Tar Haja , Alnafisah Abrar S. , Salmi-Mani Hanène , Kouki Noura , Alminderej Fahad M. , Lalevée Jacques
Published: August 2023

In this study, we developed highly efficient nonwoven membranes by modifying the surface of polypropylene (PP) and poly(butylene terephthalate) (PBT) through photo-grafting polymerization. The nonwoven membrane surfaces of PP and PBT were grafted with poly(ethylene glycol) diacrylate (PEGDA) in the presence of benzophenone (BP) and metal salt. We immobilized tertiary amine groups as BP synergists on commercial nonwoven membranes to improve PP and PBT surfaces. In situ Ag, Au, and Au/Ag nanoparticle formation enhances the nonwoven membrane surface. SEM, FTIR, and EDX were used to analyze the surface. We evaluated modified nonwoven membranes for photocatalytic activity by degrading methylene blue (MB) under LED and sunlight. Additionally, we also tested modified membranes for antibacterial activity against E. coli. The results indicated that the modified membranes exhibited superior efficiency in removing MB from water. The PBT showed the highest efficiency in dye removal, and bimetallic nanoparticles were more effective than monometallic. Modified membranes exposed to sunlight had higher efficiency than those exposed to LED light, with the PBT/Au/Ag membrane showing the highest dye removal at 97% within 90 min. The modified membranes showed reuse potential, with dye removal efficiency decreasing from 97% in the first cycle to 85% in the fifth cycle.
Amorphous Solid Dispersion as Drug Delivery Vehicles in Cancer
Authors: Budiman Arif , Handini Annisa Luthfiyah , Muslimah Mutia Nur , Nurani Neng Vera , Laelasari Eli , Kurniawansyah Insan Sunan , Aulifa Diah Lia
Published: August 2023

Cancer treatment has improved over the past decades, but a major challenge lies in drug formulation, specifically for oral administration. Most anticancer drugs have poor water solubility which can affect their bioavailability. This causes suboptimal pharmacokinetic performance, resulting in limited efficacy and safety when administered orally. As a result, it is essential to develop a strategy to modify the solubility of anticancer drugs in oral formulations to improve their efficacy and safety. A promising approach that can be implemented is amorphous solid dispersion (ASD) which can enhance the aqueous solubility and bioavailability of poorly water-soluble drugs. The addition of a polymer can cause stability in the formulations and maintain a high supersaturation in bulk medium. Therefore, this study aimed to summarize and elucidate the mechanisms and impact of an amorphous solid dispersion system on cancer therapy. To gather relevant information, a comprehensive search was conducted using keywords such as “anticancer drug” and “amorphous solid dispersion” in the PubMed, Scopus, and Google Scholar databases. The review provides an overview and discussion of the issues related to the ASD system used to improve the bioavailability of anticancer drugs based on molecular pharmaceutics. A thorough understanding of anticancer drugs in this system at a molecular level is imperative for the rational design of the products.
Effect of Nitrogen Arc Discharge Plasma Treatment on Physicochemical Properties and Biocompatibility of PLA-Based Scaffolds
Authors: Laput Olesya A. , Vasenina Irina V. , Korzhova Alena G. , Bryuzgina Anastasia A. , Khomutova Ulyana V. , Tuyakova Sitora G. , Akhmadeev Yuriy H. , Shugurov Vladimir V. , Bolbasov Evgeny N. , Tverdokhlebov Sergei I. , Chernyavskii Aleksandr V. , Kurzina Irina A.
Published: August 2023

The effect of low-temperature arc discharge plasma treatment in a nitrogen atmosphere on the modification of the physicochemical properties of PLA-based scaffolds was studied. In addition, the cellular-mediated immune response when macrophages of three donors interact with the modified surfaces of PLA-based scaffolds was investigated. PLA surface carbonization, accompanied by a carbon atomic concentration increase, was revealed to occur because of plasma treatment. Nitrogen plasma significantly influenced the PLA wettability characteristics, namely, the hydrophilicity and lipophilicity were improved, as well as the surface energy being raised. The viability of cells in the presence of the plasma-modified PLA scaffolds was evaluated to be higher than that of the initial cells.
Anti-Melanogenesis and Anti-Photoaging Effects of the Sulfated Polysaccharides Isolated from the Brown Seaweed Padina boryana
Authors: Wang Lei , Jayawardena Thilina U. , Kim Young-Sang , Wang Kaiqiang , Fu Xiaoting , Ahn Ginnae , Cha Seon-Heui , Kim Jeong Gyun , Lee Jung Suck , Jeon You-Jin
Published: August 2023

Sulfated polysaccharides isolated from seaweeds are thought of as ideal ingredients in the pharmaceutical, nutraceutical, and cosmetics industries. Our previous study isolated and characterized sulfated polysaccharides from Padina boryana. The sulfated polysaccharides of Padina boryana (PBP) were extracted, and the antioxidant activity of PBP was evaluated. The results indicate that PBP possesses antioxidant effects and potential in the cosmetic industry. To further investigate the potential of PBP in cosmetics, the photoprotective and anti-melanogenesis effects of PBP were evaluated. The anti-melanogenesis test results display that PBP reduced the melanin content in the murine melanoma cells stimulated by alpha melanocyte-stimulating hormone from 203.7% to 183.64%, 144.63%, and 127.57% at concentrations of 25 μg/mL, 50 μg/mL, and 100 μg/mL, respectively. The anti-photodamage test results showed that PBP significantly protected skin cells against UVB-stimulated photodamage. PBP suppressed human epidermal keratinocyte (HaCaT cell) death by inhibiting apoptosis and reducing the level of intracellular reactive oxygen species. The intracellular reactive oxygen species level of HaCaT cells irradiated by UVB was reduced from 192.67% to 181.22%, 170.25%, and 160.48% by 25 μg/mL, 50 μg/mL, and 100 μg/mL PBP, respectively. In addition, PBP remarkably reduced UVB-induced human dermal fibroblast damage by suppressing oxidative damage, inhibiting collagen degradation, and attenuating inflammatory responses. These results indicate that PBP possesses photoprotective and anti-melanogenesis activities and suggest that PBP is a potential ingredient in the cosmetic industry.
CFD-DEM Simulation of Fast Fluidization of Fine Particles in a Micro Riser
Authors: Wu Guorong , Li Qiang , Zuo Zhanfei
Published: August 2023

In recent years, the discrete element method (DEM) has gradually been applied to the traditional fluidization simulation of fine particles in a micro fluidized bed (MFB). The application of DEM in the simulating fast fluidization of fine particles in MFB has not yet received attention. This article presents a drag model that relies on the surrounding environment of particles, namely the particle circumstance-dependent drag model or PCDD model. Fast fluidization in an MFB of fine particles is simulated using DEM based on the PCDD model. Simulations indicate that the local structure in an MFB exhibits particle aggregation, which is a natural property of fast fluidization, forming a structure where a continuous dilute phase and dispersed concentrated phase coexist. There exists a strong effect of solid back-mixing in an MFB, leading to relatively low outlet solid flux. The gas back-mixing effect is, however, not so distinct. The axial porosity shows a monotonically increasing distribution with the bed height but does not strictly follow the single exponential distribution. The solid volume fraction at the bottom of the bed is significantly lower than the correlated value in CFB. The axial heterogeneous distribution of the cross-sectional average porosity in the lower half of the bed is also weakened. The radial porosity shows a higher distribution pattern in the central region and a lower one in the sidewall region.
Influence of Blade Trailing-Edge Filing on the Transient Characteristics of the Centrifugal Pump during Startup
Authors: Ding Hongchang , Ge Fei , Wang Kai , Lin Fanyun
Published: August 2023

During the startup process of a centrifugal pump, the vibration and noise problems caused by unsteady flow are the focus of attention, and pressure pulsation is one of the main reasons for this problem. In the current research, a special impeller with blade pressure side trimming was proposed to reduce the strong pressure pulsation phenomenon during the startup process of centrifugal pumps. This article uses numerical simulation methods to simulate three typical blade trailing edges: original trailing edge (OTE), pressure side long linear (LLPS), and pressure side short linear (SLPS), and verifies them with experimental results. The results indicate that although the head of the centrifugal pump after filing has been reduced, its efficiency has been improved to a certain extent. Thirteen monitoring points were set up near the impeller outlet circumference and volute tongue to analyze the changes in pressure pulsation, verifying that blade trimming has a significant inhibitory effect on pressure pulsation during the startup of centrifugal pumps. The average maximum pressure pulsation amplitude of all monitoring points decreased by 32.23%, and the maximum pressure pulsation amplitude decreased by 56%. Blade trimming can affect the internal flow field distribution of centrifugal pumps. By analyzing the static pressure distribution, velocity streamline distribution, and vorticity distribution at the middle interface of three different impellers during startup, it was verified that there is a close relationship between pressure pulsation and unsteady flow structure during startup. The final conclusion is that blade trimming has a significant inhibitory effect on the pressure pulsation of the centrifugal pump during startup, and the impeller outlet vorticity is significantly reduced. The scheme proposed in this study has far-reaching prospects in the design of low noise centrifugal pumps.
Coating Composites Based on Polyurea Elastomers with Increased Fire Resistance and Their Use as Roofing Systems
Authors: Dukarski Wojciech , Rykowska Iwona , Krzyżanowski Piotr , Paciorek-Sadowska Joanna , Isbrandt Marek
Published: August 2023

This paper presents the results of tests on elastomer coatings based on polyurea–polyurethane formulation with increased fire parameters. Coatings modified with flame retardants: bis(phenylphosphate) resorcinol (RDP), trischloropropyl phosphate (TCPP), and aluminum hydroxide (ATH) were tested. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA/DTG) were used to investigate the structure and thermal stability. The effectiveness of resorcinol bis(phenylphosphate) (RDP), tris chloropropyl phosphate (TCPP), and aluminum hydroxide (ATH) on heat release rate (HRR), smoke release rate (RSR), and oxygen consumption was evaluated using cone calorimetry. The cone calorimetry results were correlated with the mechanical properties of the coatings. The cone calorimetry analysis showed suitable organophosphorus flame retardant (FR) performance, significantly decreasing HRR and oxygen consumption. Additionally, 15% TCPP caused a reduction of HRR by over 50%, obtaining 211.4 kW/m2 and pHRR by over 55%, reaching 538.3 kW/m2. However, organophosphorus flame retardants caused a significant deterioration of mechanical properties simultaneously. Introducing a mixture of two FRs (RDP/TCPP) resulted in obtaining a coating with improved fire resistance and maintained good mechanical strength. The polyurea–polyurethane coating, modified with a mixture of two RDP/TCPP retardants (10:5), was simulated for the burning of roof systems. The result of the simulation was assessed positively. Thus, finally, it was confirmed that the proposed polyurea–polyurethane coating achieved the assumed flame retardant level.
Optimal Discrete Element Parameters for Black Soil Based on Multi-Objective Total Evaluation Normalized-Response Surface Method
Authors: Wang Zhipeng , Zhu Tong , Wang Youzhao , Ma Feng , Zhao Chaoyue , Li Xu
Published: August 2023

The lack of accurate black soil simulation model parameters in the design and optimization of soil remediation equipment has led to large errors in simulation results and simulation outcomes, which to some extent restricts the development of soil remediation equipment. Accurate discrete element parameters can improve the efficiency of soil remediation equipment. To improve the reliability of the discrete element contact parameters for black soil, a set of optimal discrete element contact parameters was found that could comprehensively represent a variety of particle sizes and minimize error. In this paper, the best discrete element contact parameters were selected by using a multi-indicator total evaluation normalization method combined with the response surface method, combined with black soil solid and simulated stacking tests. First, the physical parameters of the black soil and the accumulation angle were determined. Next, Plackett–Burman tests were carried out for each grain size in turn to obtain the contact parameters that had a significant effect on the black soil accumulation angle. The important parameters obtained for different particle sizes are all as follows: black soil–black soil static friction coefficient, black soil–black soil rolling friction coefficient, and black soil–stainless steel rolling friction coefficient. In conjunction with the Plackett–Burman test screening results, the steepest climb test was designed for six grain sizes to optimize the range of values. To find the optimal contact parameters for the different particle sizes based on the final results of Box–Behnken experiments, the discrete element parameters of black soil were optimized for the different particle sizes of black soil by using the multi-indicator total evaluation normalization method and response surface method. The results showed that the black soil–black soil static friction coefficient was 1.045, the black soil–black soil rolling friction coefficient was 0.464, and the black soil–stainless steel rolling friction coefficient was 0.215. The errors for each particle size were reduced by 0.89%, 0.7%, 0.84%, 0.57%, 0.71%, and 0.76% for the best combination of parameters before and after normalization, with an average error reduction of 0.745%. This data provides some reference value for the design and optimization of soil remediation equipment.
Improving Biomethanol Synthesis via the Addition of Extra Hydrogen to Biohydrogen Using a Reverse Water–Gas Shift Reaction Compared with Direct Methanol Synthesis
Authors: Krekkeitsakul Kuntima , Jitrwung Rujira , Patthaveekongka Weerawat , Hudakorn Teerasak
Published: August 2023

Conventionally, methanol is derived from a petroleum base and natural gas, but biomethanol is obtained from biobased sources, which can provide a good alternative for commercial methanol synthesis. The fermentation of molasses to produce biomethanol via the production of biohydrogen (H2 and CO2) was studied. Molasses concentrations of 20, 30, or 40 g/L with the addition of 0, 0.01, or 0.1 g/L of trace elements (TEs) (NiCl2 and FeSO4·7H2O) were investigated, and the proper conditions were a 30 g/L molasses solution combined with 0.01 g/L of TEs. H2/CO2 ratios of 50/50% (v/v), 60/40% (v/v), and 70/30% (v/v) with a constant feed rate of 60 g/h for CO2 conversion via methanol synthesis (MS) and the reverse water–gas shift (RWGS) reaction were studied. MS at temperatures of 170, 200, and 230 °C with a Cu/ZnO/Al2O3 catalyst and pressure of 40 barg was studied. Increasing the H2/CO2 ratio increased the maximum methanol product rate, and the maximum H2/CO2 ratio of 70/30% (v/v) resulted in methanol production rates of 13.15, 17.81, and 14.15 g/h, respectively. The optimum temperature and methanol purity were 200 °C and 62.9% (wt). The RWGS was studied at temperatures ranging from 150 to 550 °C at atm pressure with the same catalyst and feed. Increasing the temperature supported CO generation, which remained unchanged at 21 to 23% at 500 to 550 °C. For direct methanol synthesis (DMS), there was an initial methanol synthesis (MS) reaction followed by a second methanol synthesis (MS) reaction, and for indirect methanol synthesis (IMS), there was a reverse water–gas shift (RWGS) reaction followed by methanol synthesis (MS). For pathway 1, DMS (1st MS + 2nd MS), and pathway 2, IMS (1st RWGS + 2nd MS), the same optimal H2/CO2 ratio at 60/40% (v/v) or 1.49/1 (mole ratio) was determined, and methanol production rates of 1.04 (0.033) and 1.0111 (0.032) g/min (mol/min), methanol purities of 75.91% (wt) and 97.98% (wt), and CO2 consumptions of 27.32% and 57.25%, respectively, were achieved.
The Catalytic Upgrading Performance of NiSO4 and FeSO4 in the Case of Ashal’cha Heavy Oil Reservoir
Authors: Abdelsalam Yasser I. I. , Akhmetzyanova Leysan A. , Galiakhmetova Lilia Kh. , Baimukhametov Gadel F. , Davletshin Rustam R. , Dengaev Aleksey V. , Aliev Firdavs A. , Vakhin Alexey V.
Published: August 2023

Aquathermolysis is a promising process for improving the quality of heavy oil under reservoir conditions. However, the application of catalysts during the process can significantly promote the transformation of the heavy fragments and heteroatom-containing compounds of crude oil mixtures into low-molecular-weight hydrocarbons. This research paper conducted a comparative analysis of the catalytic effectiveness of water-soluble metal salts like NiSO4 and FeSO4 in the process of aquathermolysis to upgrade heavy oil samples extracted from the Ashal’cha reservoir. The temperature of the experiment was 300 °C for a duration of 24 h. Compared to the viscosity of the native crude oil, the Fe nanoparticles contributed to a 60% reduction in viscosity. The viscosity alteration is explained by the chemical changes observed in the composition of heavy oil after catalytic (FeSO4) aquathermolysis, where the asphaltene and resin contents were altered by 7% and 17%, accordingly. Moreover, the observed aquathermolytic upgrading of heavy oil in the presence of FeSO4 led to an increase in the yield of gasoline fraction by 13% and diesel fraction by 53%. The H/C ratio, which represents the hydrogenation of crude oil, increased from 1.52 (before catalytic upgrading) to 1.99 (after catalytic upgrading). The results of Chromatomass (GC MS) and Fourier-transform infrared spectroscopy (FT-IR) show the intensification of destructive hydrogenation reactions in the presence of water-soluble catalysts. According to the XRD and SEM-EDX results, the metal salts are thermally decomposed during the aquathermolysis process into the oxides of corresponding metals and are particularly sulfided by the sulfur-containing aquathermolysis products.