bluuebunny/crossref_metadata_2025 huggingface dataset:
Biogenic Hydrogen Sulfide Production Using Elemental Sulfur and Low-Cost Organic Substrates to Remove Metal Ions from Mining Effluents
Authors: Martínez Cristian , Viedma Pabla , Cárdenas Franco , Cotoras Davor
Published: April 2023

One of the best technologies available for metal removal from mining effluents is the precipitation of metals as sulfides. However, the high cost and difficulty in managing reagents limit its widespread application. Recent literature suggests the use of sulfur-reducing bacteria (S°RB) as a safe and effective alternative to producing H2S. Nevertheless, direct substrates for S°RB are high-cost low molecular compounds. This research aimed to evaluate the ability to produce sulfides by sulfur-reducing consortia in fixed-bed bioreactors using complex organic substrates. Consortia enriched using cellulose or Spirulina as electron donors were phylogenetically characterized by fluorescent in situ hybridization. Microorganisms belonging to Bacteria and Archaea were involved, being the most representative of the δ-Proteobacterias. The results obtained in test tube culture indicated that these consortia could use cellulose and Spirulina in alkaline conditions, resulting in high sulfide production. Upflowed fixed-bed bioreactors were implemented to establish optimal parameters., resulting in H2S volumetric productivities ranging from 1.94 to 2.94 mol/m3∙day. In conclusion, an active biomass with significant sulfidogenic activity can be generated in bioreactors under an upflowed regime using cellulose or Spirulina.
Preparation of Porous Hydroxyethyl Cellulose Materials to Utilize Lactic Acid with Vacuum-Assisted Process
Authors: Lee Haeun , Nam Kung Do Chun , Kang Sang Wook
Published: April 2023

For the first time, we succeeded in manufacturing a 2-hydroxyethyl cellulose (HEC)-based composite membrane with improved thermal stability, for use as a battery separator, coating a HEC polymer solution to a polypropylene (PP) support and using a vacuum-assisted process. A HEC polymer solution was prepared by utilizing HEC and lactic acid (LA) as a plasticizer. A vacuum-assisted process was used to move ethanol, which a mobile phase to permeate a plasticized region in the HEC polymer side for pore formation. The pores formed with uniform nano sizes, and areas in which some large pores formed were observed. The thermal stability of the composites was measured using TGA. The thermal decomposition temperatures were measured at about 250 °C for the neat HEC, about 210 °C for the HEC/LA film, and about 335 °C for the HEC/LA/PP membrane before the process. After the vacuum-assisted process, the first and second thermal decomposition were observed at about 360 °C and 450 °C, respectively. The HEC/LA/PP membrane after the process showed greater thermal stability than before the process. This means that the adhesion between the HEC polymer and the PP support was created through the rearrangement of the HEC chain, as LA escaped after the process, and it was seen indirectly that the mechanical strength was enhanced. In particular, the surface of the membrane was observed by SEM to investigate whether the HEC penetrated into the PP to block its pores, and whether the HEC region collapsed. Furthermore, the interaction of the HEC chain with the additives and the rearrangement of the HEC was confirmed using FT-IR. As a result, we demonstrated that the mechanical strength and thermal stability of the manufactured HEC/LA/PP membrane were enhanced.
A Short Review of Research Progress on the Synthesis Approaches of Aza-Dibenzocyclooctyne Derivatives
Authors: He Yinming , Liu Li , Cheng Liang
Published: April 2023

Cyclooctyne molecules have found wide applications in the strain-promoted azide–alkyne cycloaddition (SPAAC) reactions, which avoid the biotoxicity caused by the use of Cu(I) catalysts. Among the various cyclooctyne systems, dibenzocyclooctyne (DBCO) series have displayed the highest reaction activity. However, the synthesis processes of such structures are time-consuming, which to some extent limit their large-scale development and application. This review has summarized current synthesis routes of two DBCO molecules, aza-dibenzocyclooctyne (DIBAC) and biarylazacyclooctynone (BARAC).
The Development of Naringin for Use against Bone and Cartilage Disorders
Authors: Gan Juwen , Deng Xiaolan , Le Yonghong , Lai Jun , Liao Xiaofei
Published: April 2023

Bone and cartilage disorders are the leading causes of musculoskeletal disability. There is no absolute cure for all bone and cartilage disorders. The exploration of natural compounds for the potential therapeutic use against bone and cartilage disorders is proving promising. Among these natural chemicals, naringin, a flavanone glycoside, is a potential candidate due to its multifaceted pharmacological activities in bone and cartilage tissues. Emerging studies indicate that naringin may promote osteogenic differentiation, inhibit osteoclast formation, and exhibit protective effects against osteoporosis in vivo and in vitro. Many signaling pathways, such as BMP-2, Wnt/β-catenin, and VEGF/VEGFR, participate in the biological actions of naringin in mediating the pathological development of osteoporosis. In addition, the anti-inflammatory, anti-oxidative stress, and anti-apoptosis abilities of naringin also demonstrate its beneficial effects against bone and cartilage disorders, including intervertebral disc degeneration, osteoarthritis, rheumatoid arthritis, bone and cartilage tumors, and tibial dyschondroplasia. Naringin exhibits protective effects against bone and cartilage disorders. However, more efforts are still needed due to, at least in part, the uncertainty of drug targets. Further biological and pharmacological evaluations of naringin and its applications in bone tissue engineering, particularly its therapeutic effects against osteoporosis, might result in developing potential drug candidates.
Chiral Indolizinium Salts Derived from 2-Pyridinecarbaldehyde—First Diastereoselective Syntheses of (−)-1-epi-lentiginosine
Authors: Rodriguez-Matsui Hisami , Aparicio David M. , Orea María L. , Juárez Jorge R. , Gómez-Calvario Victor , Gnecco Dino , Carrasco-Carballo Alan , Terán Joel L.
Published: April 2023

The first diastereoselective synthesis of (−)-1-epi-lentiginosine from a common chiral trans-epoxyamide derived from 2-pyridincarbaldehyde is reported. This methodology involves a sequential oxirane ring opening and intramolecular 5-exo-tet cyclization of tosylate trans-epoxyalcohol to afford a diastereomeric mixture of indolizinium salts in a one-pot fashion, followed by regio- and diastereospecific pyridinium ring reduction.
Electrochemical Lithium Extraction with Gas Flushing of Porous Electrodes
Authors: Wang Shengyao , Yu Xuyu , Hu Xuejiao
Published: April 2023

Electrochemical extraction of lithium from seawater/brine is receiving more and more attention because of its environment-friendly and energy-saving features. In this work, an electrochemical lithium extraction system with gas flushing of porous electrodes is proposed. We verified that the operation of multiple gas washes can significantly reduce the consumption of ultrapure water during the solution exchange and save the time required for the continuous running of the system. The water consumption of multiple gas flush operations is only 1/60 of that of a normal single flush to obtain a purity close to 100% in the recovery solution. By comparing the ion concentration distribution on the electrode surface in flow-through and flow-by-flow modes, we demonstrate that the flow-through mode performs better. We also verified the lithium extraction performance of the whole system, achieving a purity close to 100% and average energy consumption of 0.732 kWh∙kg−1 in each cycle from the source solution of the simulated Atacama salt lake water. These results provide a feasible approach for the large-scale operation of electrochemical lithium extraction from seawater/brine.
Inverse Correlation of Superoxide Dismutase and Catalase with Type 2 Diabetes among Rural Thais
Authors: Promyos Natnicha , Phienluphon Pornpimol Panprathip , Wechjakwen Naruemon , Lainampetch Jirayu , Prangthip Pattaneeya , Kwanbunjan Karunee
Published: April 2023

Oxidative stress contributes to defective antioxidant defenses, which may lead to type 2 diabetes (T2D). This study aimed to elucidate the T2D risks and antioxidant defenses by investigating the superoxide dismutase (SOD), catalase (CAT), vitamin A, and vitamin E status. We observed 102 participants aged 35–66 years from Sung Neon, Nakhon Ratchasima, Thailand. The blood samples were collected to measure the SOD, CAT, vitamin A, and vitamin E concentrations. The SOD and CAT activities were inversely associated with T2D risk. When compared with participants in the highest quartile of SOD and CAT, those in the lowest quartile for T2D risk obtained multivariable-adjusted odds ratios of 4.77 (SOD: 95% confident interval CI, 1.01–22.40; p = 0.047) and 4.22 (CAT: 95% CI, 1.07–16.60; p = 0.039). The possible influencing factors (e.g., physical activity, total cholesterol, and triglyceride) might mediate the association of SOD and CAT with T2D risk. Meanwhile, the relationship between vitamin A and vitamin E concentrations and T2D risk was insignificant. In conclusion, lower concentrations of antioxidant enzyme activity (SOD and CAT) may be an additional risk factor for T2D.
How Does the Frequency of Eating-Alone among Older People in Korea Affect Their Health and Dietary Behavior?
Authors: Kwon Yongseok , Hong Kyung Hee , Park Yoo-Kyung , Kim Sohye
Published: April 2023

This study examined the relationship between general population characteristics and diet-related factors pertaining to eating alone for older adults (65 years and older) in Korea. This study used the Korea National Health and Nutrition Examination Survey (KNHANES), 2016–2020, and the target population was 7037 Koreans aged 65 years or older who participated in the nutritional survey and health interview. Eating alone variables were classified as follows. Eating together all day means “eating together”, eating only one meal a day means “1/day”, eating two meals a day alone means “2/day”, and “3/day” means eating three meals a day alone. The main results are as follows. The rate of moderate or severe food insecurity was 3.41% in the “eating together” group to 7.86% in the “3/day” group, which was 4.45% higher in the “3/day” group. Fruit + vegetable intake among food intake lowered by about 35 g from 301.2 g in the “eating together” group to 266.2 g in the “3 day” group. In addition, as a result of analyzing the prevalence of depression using the PHQ-9 score, the “3/day” group had a 1.775 to 2.464 times higher risk of depression than the “eating together” group. Finally, EQ-5D variables and quality of life scores were significantly lowered from the “eating together” group to the “3/day” group. Overall, higher frequency of eating alone was associated with food safety, essential food intake, and quality of life. Based on these results, it is thought that a dietary life support program such as the eating together program is necessary to improve the quality of life of the older people who eat alone.
Piezoelectric Nanomaterials Activated by Ultrasound in Disease Treatment
Authors: Yang Shiyuan , Wang Yuan , Liang Xiaolong
Published: April 2023

Electric stimulation has been used in changing the morphology, status, membrane permeability, and life cycle of cells to treat certain diseases such as trauma, degenerative disease, tumor, and infection. To minimize the side effects of invasive electric stimulation, recent studies attempt to apply ultrasound to control the piezoelectric effect of nano piezoelectric material. This method not only generates an electric field but also utilizes the benefits of ultrasound such as non-invasive and mechanical effects. In this review, important elements in the system, piezoelectricity nanomaterial and ultrasound, are first analyzed. Then, we summarize recent studies categorized into five kinds, nervous system diseases treatment, musculoskeletal tissues treatment, cancer treatment, anti-bacteria therapy, and others, to prove two main mechanics under activated piezoelectricity: one is biological change on a cellular level, the other is a piezo-chemical reaction. However, there are still technical problems to be solved and regulation processes to be completed before widespread use. The core problems include how to accurately measure piezoelectricity properties, how to concisely control electricity release through complex energy transfer processes, and a deeper understanding of related bioeffects. If these problems are conquered in the future, piezoelectric nanomaterials activated by ultrasound will provide a new pathway and realize application in disease treatment.
Extending the Imaging Depth of Field through Scattering Media by Wavefront Shaping of Non-Diffraction Beams
Authors: Han Tongyu , Peng Tong , Li Runze , Wang Kaige , Sun Dan , Yao Baoli
Published: April 2023

Increasing the depth of field (DOF) is a crucial issue for imaging through scattering media. In this paper, an improved genetic algorithm is used to modulate the wavefront of light through scattering media, by which high-quality refocusing and imaging through scattering media are achieved. Then, the DOF of the imaging system is effectively extended by further modulating the refocused beam into a non-diffraction beam. Two kinds of non-diffraction beams, i.e., a Bessel beam and Airy beam, were produced as a demonstration. The experimental results show that compared to the Gaussian beam, the DOF of the imaging system by combining the wavefront shaping and non-diffraction Bessel beam or Airy beam can be improved by a factor of 1.1 or 1.5, respectively. The proposed method is helpful for the technical development of high-quality imaging through scattering media with a large DOF.
Dynamics of Gas Ionization by Laser Pulses with Different Envelope Shapes
Authors: Emelina Anna , Laryushin Ivan , Romanov Alexander
Published: April 2023

The properties of the dynamics of gas ionization under the action of femtosecond ionizing laser pulses with various envelope shapes are studied. It is shown that the duration of ionization in the saturation regime (at a high final degree of ionization) can either increase or decrease with an increase in the peak intensity of the ionizing pulse, depending on the shape of its envelope. We also determined the influence of the pulse shape on the spectrum of Brunel harmonics and the terahertz yield when two-color pulses are used.
Hemodynamic Responses to a Handgrip Exercise Session, with and without Blood Flow Restriction, in Healthy Volunteers
Authors: Filippou Spyridoula , Iakovidis Paris , Lytras Dimitrios , Kasimis Konstantinos , Solomonidou Freideriki , Kopsidas Christos
Published: April 2023

Exercising at submaximal intensity with a hand dynamometer causes mild hemodynamic adaptations that can improve cardiovascular function. However, hemodynamic responses and fatigue have not been adequately studied in an isometric exercise protocol combined with blood flow restriction (BFR). Our study aimed to examine and compare acute hemodynamic responses and muscle fatigue after an isometric exercise session using a handgrip dynamometer, with and without BFR. Twelve volunteers performed the exercise protocol, with and without BFR, at random, with the BFR pressure set at 140 mmHg. Arterial blood pressure (BP), heart rate (HR), oxygen saturation (SpO2), and muscle fatigue were measured before, during, and 15 min after the completion of the exercise session. Without BFR, we noticed a slight, albeit statistically insignificant, HR increase. The variations found in systolic and diastolic pressure were small and statistically insignificant. Furthermore, blood oxygen saturation (SpO2) did not change significantly. Significantly higher levels of fatigue were found in exercise with BFR, compared to without BFR, at the end of each set of isometric contractions. In conclusion, a handgrip exercise session with mild BFR does not alter the acute hemodynamic responses to exercise in healthy volunteers. However, it results in higher muscle fatigue compared to that experienced after exercise without BFR.
Identification of Cumin (Cuminum cyminum) MicroRNAs through Deep Sequencing and Their Impact on Plant Secondary Metabolism
Authors: Reyes-Calderón Almendra , Gutiérrez-García Claudia , Urióstegui-Pena Andrea G. , Srivastava Aashish , Aguilar-Marcelino Liliana , Iqbal Hafiz M. N. , Ahmed Shiek S. S. J. , Paul Sujay , Sharma Ashutosh
Published: April 2023

The pharmacological properties of plants lie in the content of secondary metabolites that are classified into different categories based on their biosynthesis, structures, and functions. MicroRNAs (miRNAs) are small non-coding RNA molecules that play crucial post-transcriptional regulatory roles in plants, including development and stress-response signaling; however, information about their involvement in secondary metabolism is still limited. Cumin is one of the most popular seeds from the plant Cuminum cyminum, with extensive applications in herbal medicine and cooking; nevertheless, no previous studies focus on the miRNA profile of cumin. In this study, the miRNA profile of C. cyminum and its association with the biosynthesis of secondary metabolites were determined using NGS technology. The sequencing data yielded 10,956,054 distinct reads with lengths ranging from 16 to 40 nt, of which 349 miRNAs were found to be conserved and 39 to be novel miRNAs. Moreover, this work identified 1959 potential target genes for C. cyminum miRNAs. It is interesting to note that several conserved and novel miRNAs have been found to specifically target important terpenoid backbone, flavonoid biosynthesis, and lipid/fatty acid pathways enzymes. We believe this investigation will aid in elucidating the implications of miRNAs in plant secondary metabolism.
Antioxidant and Antibacterial Activities of the Leaf and Stem Extracts of Combretum molle (R. Br. ex G. Don.) Engl. & Diels
Authors: Parusnath Myuri , Naidoo Yougasphree , Singh Moganavelli , Kianersi Farzad , Dewir Yaser Hassan
Published: April 2023

Medicinal plants offer reasonable and accessible alternatives to synthetic drugs and are often devoid of the adverse side effects, toxicity, and pathogenic resistance associated with synthetic medicine. Combretum molle has been utilized in African traditional medicinal practices and purportedly contains bioactive compounds with medicinally beneficial effects. This study investigated the hexane, chloroform, and methanol leaf and stem extracts for their antioxidant properties using the 2,2′-diphenyl-1-picrylhydrazyl radical scavenging and ferric-reducing antioxidant power assays. The study additionally analyzed the methanol extracts for their antibacterial activity against Gram-negative Escherichia coli (ATCC 25922) and Gram-positive Staphylococcus aureus (ATCC 25923) bacteria using agar well diffusion. Relative to the scavenging activity of the ascorbic acid control (79.15 ± 0.63% at 15 µg/mL to 94.61 ± 0.12% at 240 µg/mL), the plant’s radical scavenging activities were exceptionally high in the methanolic leaf and stem extracts (p < 0.05), ranging from 94.58 ± 1.10% at 15 µg/mL to 99.22 ± 0.30% at 240 µg/mL and 91.57 ± 1.71% at 15 µg/mL to 99.60 ± 0.20% at 240 µg/mL, respectively, suggesting a strong capacity to donate hydrogen ions. High scavenging activities were additionally observed in the chloroform stem (78.68 ± 1.18% at 15 µg/mL to 98.14 ± 1.22% at 240 µg/mL) and hexane leaf (72.12 ± 4.38% at 15 µg/mL to 89.87 ± 1.50% at 240 µg/mL) extracts (p < 0.05). All extracts exhibited poor ferric-reducing abilities in relation to the gallic acid control (100 ± 0.00%) at all concentrations (p < 0.05). The leaf and stem extracts exhibited broad-spectrum antibiotic capabilities against both tested strains, with significant activity at higher concentrations (p < 0.05). Overall, both the leaf and stem extracts of C. molle exhibited similar antioxidant and antibacterial activities. These findings warrant further pharmacological research on C. molle for potential drug development.
Effect of Low Temperature on Insecticidal Protein Contents of Cotton (Gossypium herbaceum L.) in the Boll Shell and Its Physiological Mechanism
Authors: Liu Zhenyu , Ji Mingyu , He Run , Dai Yuyang , Liu Yuting , Mou Nana , Du Jianing , Zhang Xiang , Chen Dehua , Chen Yuan
Published: April 2023

Low temperature is the main factor for global natural disasters affecting the growth and distribution of plants, and cotton may be affected by low temperature and cold damage at all growth stages. In addition, the insecticidal resistance of cultivars has been reported to perform poorly or unstably due to adverse environments. The present study aimed to investigate the impact of low temperature on the levels of insecticidal protein in Bacillus thuringiensis (Bt) transgenic cotton plants during the peak boll stage. To achieve this, two Bt cotton cultivars, Sikang1 (SK1) and Sikang3 (SK3), were subjected to different temperature regimes and durations. The findings of the study demonstrated that the expression of insecticidal protein in the boll shell of Bt transgenic cotton plants was significantly inhibited under low-temperature stress. Specifically, in 2020, compared to the CK (27 °C), the insecticidal protein content in the boll shell of SK3 decreased by 28.19% after a 48 h of a 16 °C temperature. These results suggest that low-temperature stress can negatively impact the expression of insecticidal protein in Bt transgenic cotton, highlighting the need for appropriate measures to minimize its adverse effects on cotton production. In addition, the threshold temperature that leads to a significant decrease in the content of insecticidal proteins symbolizes an upward trend as the duration of stress prolongs. Decreased Bt protein content at low temperatures is associated with changes in the N metabolism. The present study revealed a significant positive correlation between the levels of glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) activities, as well as in the soluble protein levels in the boll shell and the content of the Bt protein. On the other hand, a significant negative correlation was observed between the levels of free amino acids, peptidase, and protease activities, as well as of Bt protein content. These findings suggest that, in Bt cotton production, it is crucial to remain vigilant of prolonged low-temperature disasters, which last for over 12 h and drop below 17–20 °C during the peak boll stage. Such conditions may reduce insecticidal resistance, leading to substantial economic losses.
Exogenous Application of Methyl Salicylate Induces Defence in Brassica against Peach Potato Aphid Myzus persicae
Authors: Ali Jamin , Wei Dongming , Mahamood Mohammad , Zhou Fanrui , King Patricia Jie Hung , Zhou Wenwu , Shamsi Imran Haider
Published: April 2023

Plants use a variety of secondary metabolites to defend themselves against herbivore insects. Methyl salicylate (MeSA) is a natural plant-derived compound that has been used as a plant defence elicitor and a herbivore repellent on several crop plants. The aim of this study was to investigate the effect of MeSA treatment of Brassica rapa subsp. chinensis (‘Hanakan’ pak choi) on its interactions with peach potato aphids, Myzus persicae, and their natural enemy, Diaeretiella rapae. For this, we selected two concentrations of MeSA (75 mg/L and 100 mg/L). Our results showed that aphid performance was significantly reduced on plants treated with MeSA (100 mg/L). In a cage bioassay, the MeSA (100 mg/L)-treated plants showed lower adult survival and larviposition. Similarly, the MeSA (100 mg/L)-treated plants had a significantly lower aphid settlement in a settlement bioassay. In contrast, the M. persicae aphids did not show any significant difference between the MeSA (75 mg/L)-treated and control plants. In a parasitoid foraging bioassay, the parasitoid D. rapae also did not show any significant difference in the time spent on MeSA-treated and control plants. A volatile analysis showed that the MeSA treatment induced a significant change in volatile emissions, as high numbers of volatile compounds were detected from the MeSA-treated plants. Our results showed that MeSA has potential to induce defence in Brassica against M. persicae and can be utilised in developing sustainable approaches for the management of peach potato aphids.
Genetic Diversity and Population Structure Assessed Using Microsatellite (SSR) Markers from Relict Populations of Nuphar pumila (Nymphaeaceae)
Authors: González-Toral Claudia , Cuesta Candela , Cires Eduardo
Published: April 2023

The genus Nuphar (Nymphaeaceae) comprises aquatic plant species inhabiting freshwater bodies of the Northern hemisphere temperate regions known as yellow water-lilies. Nuphar lutea and N. pumila are the only representatives in the European continent and present different ecologies: the former is a widespread generalist, while the latter is restricted to northern latitudes or high-altitudes due to its requirements for colder and oligotrophic waters. The Central Europe mountainous areas, the Massif Central (France) and the Cantabrian Mountains (north Iberian Peninsula) harbor relict isolated N. pumila populations endangered by eutrophication and hybridization with N. lutea. We aim to detect hybridization processes in the Massif Central and Cantabrian Mountains populations and compare the genetic diversity of N. pumila in the relict populations of Central Europe by using microsatellite (SSR) markers. No evidence of hybridization was found in the Iberian population, whereas the admixture between N. pumila and N. lutea in the Massif Central populations could be due to hybridization or ancient introgression. Our current knowledge would benefit from genetic diversity studies focusing on both species throughout their distributional range. The Iberian and Massif Central N. pumila populations were genetically distinct, representing two different clusters from other relict populations, with low genetic diversity and a genetic boundary within Central Europe.
Study of Cannabis Oils Obtained from Three Varieties of C. sativa and by Two Different Extraction Methods: Phytochemical Characterization and Biological Activities
Authors: Pino Sebastián , Espinoza Luis , Jara-Gutiérrez Carlos , Villena Joan , Olea Andrés F. , Díaz Katy
Published: April 2023

Currently, much effort is being placed into obtaining extracts and/or essential oils from Cannabis sativa L. for specific therapeutic purposes or pharmacological compositions. These potential applications depend mainly on the phytochemical composition of the oils, which in turn are determined by the type of C. sativa and the extraction method used to obtain the oils. In this work, we have evaluated the contents of secondary metabolites, delta-9-tetrahydrocannabinol (THC), and cannabidiol (CBD), in addition to the total phenolic, flavonoids, and anthraquinone content in oils obtained using solid–liquid extraction (SLE) and supercritical fluid extraction (SCF). Different varieties of C. sativa were chosen by using the ratio of THC to CBD concentrations. Additionally, antioxidant, antifungal and anticancer activities on different cancer cell lines were evaluated in vitro. The results indicate that oils extracted by SLE, with high contents of CBD, flavonoids, and phenolic compounds, exhibit a high antioxidant capacity and induce a high decrease in the cell viability of the tested breast cancer cell line (MCF-7). The observed biological activities are attributed to the entourage effect, in which CBD, phenols and flavonoids play a key role. Therefore, it is concluded that the right selection of C. sativa variety and the solvent for SLE extraction method could be used to obtain the optimal oil composition to develop a natural anticancer agent.
Ex Vivo Transdermal Delivery of Nicotinamide Mononucleotide Using Polyvinyl Alcohol Microneedles
Authors: Sabbagh Farzaneh , Kim Beom-Soo
Published: April 2023

Nicotinamide mononucleotide (NMN), which has recently been spotlighted as an anti-aging agent, is a precursor of the coenzyme nicotinamide adenine dinucleotide that plays an important role in intracellular redox reactions. NMN capsules for oral administration currently on the market have a problem in that they are almost fully metabolized in the stomach and liver and excreted as nicotinamide. Therefore, there is a need to develop a patient-friendly delivery method that can improve the bioavailability of NMN. For this purpose, various polyvinyl alcohol (PVA)-based microneedle patches were fabricated to develop a transdermal delivery system for NMN. First, the molecular weight effect of PVA on the shape and microstructure of microneedles was studied. After selecting the optimal molecular weight PVA, the swelling of the microneedles and the ex vivo release of NMN were studied. The effect of carboxymethyl cellulose (CMC) and dimethyl sulfoxide on NMN release was also investigated. The highest NMN release of 91.94% in 18 h was obtained using a 9.5 kDa molecular weight PVA microneedle containing NMN and CMC.
New Hybrid Adsorbents Based on Polyaniline and Polypyrrole with Silicon Dioxide: Synthesis, Characterization, Kinetics, Equilibrium, and Thermodynamic Studies for the Removal of 2,4-Dichlorophenol
Authors: Bekhoukh Amina , Kiari Mohamed , Moulefera Imane , Sabantina Lilia , Benyoucef Abdelghani
Published: April 2023

In the current study, polyaniline and polypyrrole with silicon dioxide (PAni:PPy@SiO2) were combined to formulate a new adsorbent, which was examined using XRD, TEM, SEM, FTIR, TGA, and BET, and the adsorption kinetics were investigated by UV–vis spectroscopy. The optical band gap was also evaluated. The electrochemical behavior was investigated using cyclic voltammograms. Moreover, experimental conditions were used to evaluate the 2,4-dichlorophenol (2,4-DCP) adsorption based on the pH, temperature, reaction time, and initial concentration. The analytical isotherm data were determined by Langmuir, Freundlich, Temkin, Sips, and Redlich–Peterson models. For the analysis of the kinetic data, the pseudo-first- and -second-order models and the intraparticle diffusion model were investigated. It was found that this new adsorbent possessed the highest adsorption efficiency after several regeneration cycles. Furthermore, the thermodynamic parameters of adsorption, such as entropy (ΔS), enthalpy (ΔH), and standard Gibbs were measured. These results suggest that the PAni:PPy backbone can generally be better applied for the elimination of 2,4-dichlorophenol by appropriately dispersing it over the surface of suitable SiO2. This search provides a novel way to develop separable, high-performance adsorbents for adsorbing organic contamination from wastewater.
Tribological and Mechanical Applications of Liquid-Crystal-Polymer-Modified Carbon-Fiber-Reinforced Polyamide–Polyurethane Composites
Authors: Zhou Zhen , Wang Xiaoqing , Li Xiaomeng , Liu Chang , Li Guoping , Luo Yunjun
Published: April 2023

An aromatic copolyester liquid crystal polymer (LCP) was introduced into carbon-fiber-reinforced polyamide–polyurethane (CF/PA-PU) composites through melt blending to improve the tribological properties of the composites. The effects of LCP on the mechanical, processing, and thermal properties of CF/PA-PU composites were compared to those of commonly-used graphite (Gr). The results showed that at 5 wt.% LCP content, the coefficient of friction (COF) was decreased by 16.06%, and the wear rate by 32.22% in the LCP/CF/PA-PU composite compared to the CF/PA-PU composite. Furthermore, using LCP instead of Gr showed significantly improved mechanical properties and reduced processing viscosity. The tensile strength of 5%LCP/CF/PA-PU composite could reach 99.08 MPa, while the equilibrium torque was reduced, being 26.85% higher and 18.37% lower than those of CF/PA-PU composite, respectively. The thermal stability of LCP/CF/PA-PU composites was also enhanced. The addition of 5 wt.% LCP to CF/PA-PU composite increased the initial decomposition temperature by 14.19% compared to CF/PA-PU. In sharp contrast, the addition of Gr increased equilibrium torque and actual processing temperature leading to processing difficulties and instability. This approach offers a novel strategy for tribological applications and tackles the problem of high viscosity in CF/PA-PU composites.
Kinetic Analysis of Thermal Degradation of Recycled Polypropylene and Polystyrene Mixtures Using Regenerated Catalyst from Fluidized Catalytic Cracking Process (FCC)
Authors: Palmay Paul , Pillajo Leslie , Andrade Mónica , Medina Carlos , Barzallo Diego
Published: April 2023

The pyrolysis process is a thermochemical recycling process that in recent years has gained importance due to its application in plastic waste, which is one of the biggest environmental problems today. Thus, it is essential to carry out kinetic and thermodynamic analyses to understand the thermocatalytic degradation processes involved in plastic waste mixtures. In this sense, the main objective of this study is to analyze the degradation kinetics of the specific mixture of polypropylene (25%) and polystyrene (75%) with 10% mass of regenerated FCC catalyst which was recovered from conventional refining processes using 3 heating rates at 5, 10 and 15 K min−1 by thermogravimetric analysis (TGA). The obtained TGA data were compared with the isoconversional models used in this work that include Friedman (FR), Kissinger Akahira Sunose (KAS), Flynn–Wall–Ozawa (FWO), Starink (ST) and Miura–Maki (MM) in order to determine the one that best fits the experimental data and to analyze the activation energy and the pre-exponential factor; the model is optimized by means of the difference of minimum squares. Activation energy values between 148 and 308 kJ/mol were obtained where the catalytic action has been notorious, decreasing the activation energy values with respect to thermal processes.
Approaching Polycarbonate as an LFT-D Material: Processing and Mechanical Properties
Authors: Schelleis Christoph , Scheuring Benedikt M. , Liebig Wilfried V. , Hrymak Andrew N. , Henning Frank
Published: April 2023

Long-fiber thermoplastic (LFT) materials compounded via the direct LFT (LFT-D) process are very versatile composites in which polymers and continuous reinforcement fiber can be combined in almost any way. Polycarbonate (PC) as an amorphous thermoplastic matrix system reinforced with glass fibers (GFs) is a promising addition regarding the current development needs, for example battery enclosures for electromobility. Two approaches to the processing and compression molding of PC GF LFT-D materials with various parameter combinations of screw speed and fiber rovings are presented. The resulting fiber lengths averaged around 0.5 mm for all settings. The tensile, bending, Charpy, and impact properties were characterized and discussed in detail. Special attention to the characteristic charge and flow area formed by compression molding of LFT-D materials, as well as sample orientation was given. The tensile modulus was 10 GPa, while the strength surpassed 125 MPa. The flexural modulus can reach up to 11 GPa, and the flexural strength reached up to 216 MPa. PC GF LFT-D is a viable addition to the LFT-D process, exhibiting good mechanical properties and stable processability.
Antibacterial and Physicochemical Properties of Orthodontic Resin Cement Containing ZnO-Loaded Halloysite Nanotubes
Authors: Seo Jeong-Hye , Kim Kwang-Mahn , Kwon Jae-Sung
Published: April 2023

Demineralized white lesions are a common problem when using orthodontic resin cement, which can be prevented with the addition of antibacterial substances. However, the addition of antibacterial substances such as zinc oxide alone may result in the deterioration of the resin cement’s functions. Halloysite nanotubes (HNTs) are known to be biocompatible without adversely affecting the mechanical properties of the material while having the ability to load different substances. The purpose of this study was to prepare orthodontic resin cement containing HNT fillers loaded with ZnO (ZnO/HNTs) and to investigate its mechanical, physical, chemical, and antibacterial properties. A group without filler was used as a control. Three groups containing 5 wt.% of HNTs, ZnO, and ZnO/HNTs were prepared. TEM and EDS measurements were carried out to confirm the morphological structure of the HNTs and the successful loading of ZnO onto the HNTs. The mechanical, physical, chemical, and antibacterial properties of the prepared orthodontic resin cement were considered. The ZnO group had high flexural strength and water absorption but a low depth of cure (p < 0.05). The ZnO/HNTs group showed the highest shear bond strength and film thickness (p < 0.05). In the antibacterial test, the ZnO/HNTs group resulted in a significant decrease in the biofilm’s metabolic activity compared to the other groups (p < 0.05). ZnO/HNTs did not affect cell viability. In addition, ZnO was cytotoxic at a concentration of 100% in the extract. The nanocomposite developed in this study exhibited antimicrobial activity against S. mutans while maintaining the mechanical, physical, and chemical properties of orthodontic resin cement. Therefore, it has the potential to be used as an orthodontic resin cement that can prevent DWLs.
Review on the Degradation of Poly(lactic acid) during Melt Processing
Authors: Velghe Ineke , Buffel Bart , Vandeginste Veerle , Thielemans Wim , Desplentere Frederik
Published: April 2023

This review paper presents an overview of the state of the art on process-induced degradation of poly(lactic acid) (PLA) and the relative importance of different processing variables. The sensitivity of PLA to degradation, especially during melt processing, is considered a significant challenge as it may result in deterioration of its properties. The focus of this review is on degradation during melt processing techniques such as injection molding and extrusion, and therefore it does not deal with biodegradation. Firstly, the general processing and fundamental variables that determine the degradation are discussed. Secondly, the material properties (for example rheological, thermal, and mechanical) are presented that can be used to monitor and quantify the degradation. Thirdly, the effects of different processing variables on the extent of degradation are reviewed. Fourthly, additives are discussed for melt stabilization of PLA. Although current literature reports the degradation reactions and clearly indicates the effect of degradation on PLA’s properties, there are still knowledge gaps in how to select and predict the processing conditions that minimize process-induced degradation to save raw materials and time during production.
Significant Influence of Bound Rubber Thickness on the Rubber Reinforcement Effect
Authors: Chen Jian , Hu Maoyuan , Li Yuming , Li Rui , Qing Long
Published: April 2023

In this work, the contribution of different types of carbon blacks (N115, N330, N550, N660) and their primary and secondary thermally cracked recovered carbon blacks to the mechanical properties of NR composites was evaluated. The thermally cracked recovered carbon blacks were prepared by cracking the rubber composites at 500 °C and de-hybridizing them at 900 °C. The characterization of the thermally cracked recovered carbon blacks by scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy showed that carbon blacks after primary and secondary thermal cracking recovery were more prone to aggregation and exhibited a higher degree of carbon defects. The number and type of functional groups on the surface of these carbon blacks were significantly reduced. For NR composites with pristine samples added, the mechanical properties and the bound rubber content tests showed that the mechanical properties of the NR composites became weaker with the increase in carbon black particle size. The bound rubber content also decreased with increased carbon black particle size. The mechanical properties of the NR composites reinforced with carbon black recovered by primary and secondary thermal cracking would therefore decrease. The results of AFM and DSC tests further confirmed the decreasing trend of bound rubber. The present work demonstrates the effect of bound rubber content variation on the mechanical properties of rubber, demonstrates the morphology of bound rubber more visually, and provides new insights into the reinforcement theory of CB.
Optimization and Control of Propylene Production by Metathesis of 2-Butene
Authors: Andrei Andrei Maxim , Bildea Costin Sorin
Published: April 2023

This article considers the design and control of the 2-butene metathesis process. The process transforms a low-value feedstock derived from a fluid catalytic cracking unit into more valuable products. The economical optimization is applied to the preheat–reaction and separation sections, with the objective of minimizing the total annual cost. The dynamic response and control of the plant are evaluated for feed flow perturbations. Although the process control system acts as a first line of defense against potential hazards, other independent safety layers are discussed with safety limits specific to the critical equipment of the 2-butene metathesis unit. The results prove that the metathesis reaction of 2-butene over a mesoporous tungsten catalyst is economically attractive. For a 5.7 t/h feed rate consisting of 2-butene (70% molar) and n-butane (30% molar), a reaction–separation plant (without recycle) requires 6570 × 103 $ investment and has a profitability of 2300 × 103 $/year.
An Enhanced Method for Nanosecond Time Synchronization in IEEE 1588 Precision Time Protocol
Authors: Li Fei , Liu Wenyi , Qi Yueyan , Li Qiang , Liu Gaigai
Published: April 2023

The performance of time-critical systems depends heavily on time synchronization accuracy. Therefore, it is crucial to have a synchronization method that can achieve high time synchronization accuracy. In this paper, we propose a new underlying transmission architecture and new synchronization messages. On the basis of these, aiming at the time error problem of the slave clock, we propose an enhanced time synchronization method based on new synchronization messages. Furthermore, we evaluate the performance of the enhanced time synchronization method on the OMNeT++ simulator. In addition, we compare the impact of different crystal oscillator accuracies and different crystal oscillator frequencies on time synchronization accuracy, respectively. Simulation results show that the time offset is at most ±1 clock period using the enhanced time synchronization method. We realize the purpose of timing the master clock and the slave clock by counting the period of the clock signal. Therefore, we needed to round down the time count to an integer. This is the reason why −1 and 1 appear at the same time. When the crystal oscillator frequency used is 80 MHz, the system can achieve a time synchronization accuracy of ±12.5 ns; that is, a nanosecond-level time synchronization accuracy can be achieved. With the reduction of the crystal oscillator accuracy of the slave clock, the synchronization accuracy of ±1 clock period can still be achieved. With the increase in the crystal oscillator frequency, the time synchronization accuracy that can be achieved also improves. The method proposed in this paper provides a new way of thinking and has certain guiding significance for improving the time synchronization accuracy of time-critical systems.
Effect of 450 nm Visible Blue Light from Light-Emitting Diode on Escherichia coli O157:H7 in Agar Gels: Optimizing the Lighting Array and Quantitative Microbial Exposure Assessment
Authors: Jung Hwabin , Yoon Won Byong
Published: April 2023

Visible blue light emitting diodes (LED) have been studied to inactivate Escherichia coli (E. coli) O157:H7 in agar gels. The LED array was optimized to attain uniform light illumination, and the light intensity distribution was visualized through optical simulation. The uniformity of LED light intensity was assessed, and the evenly spaced array showed the best uniformity with a Petri factor of 0.99. Microbial populations in agar gels prepared with and without a dye were analyzed after light irradiation. Each segment of the gels with different heights was taken to measure microbial reduction, and the results indicated that optical properties, such as opaqueness, played an important role in microbial reduction. The agar gel without and with a dye showed a maximum reduction of <3.4 and <2.1 log CFU/g, respectively. An exposure assessment for E. coli O157:H7 was conducted based on the assumption for the agar gel product after LED illumination. The probability results indicated that a risk (>5 log CFU/g) existed mainly in the bottom layer of the sample, despite the average contamination being <5 log CFU/g. This study provides a suitable approach for designing the LED photoinactivation process and subsequent exposure assessment to avoid risk.
Coleus aromaticus Ethanolic Leaves Extract Mediates Inhibition of NF-κB Signaling Pathway in Lung Adenocarcinoma A549 Cells
Authors: Subaiea Gehad , Alafnan Ahmed , Alamri Abdulwahab , Hussain Talib , Hassoun Shimaa Mahmoud , Lila Amr Selim Abu , Khafagy El-Sayed , Katamesh Ahmed A.
Published: April 2023

Lung cancer is the second leading cause of cancer-related mortalities globally. Failure in diagnosis at early stages and limited effective chemotherapeutics has severely impeded the clinical management of patients suffering from lung carcinoma. At present, researchers across the world are focused on exploring biologically active natural products for treating various cancers, which can thus be further investigated for their chemotherapeutical potential. Coleus aromaticus is a common herb used in culinary practices and has previously been shown to possess various medicinal characteristics. In the present study, the anti-cancer effects of ethanolic extract of C. aromaticus leaves (EtOH-LCa) against non-small cell lung carcinoma (NSCLC) A549 cells were screened. It was observed that EtOH-LCa reduced the viability of A549 cells and obstructed the cell cycle progression in a concentration-dependent manner. Importantly, EtOH-LCa succeeded in instigating the production of reactive oxygen species (ROS) (p < 0.001) within A549 cells. The elevation in ROS levels was concomitantly followed by the disruption of nuclear morphology and the loss in mitochondria viability within A549 cells. In addition, EtOH-LCa was successful in increasing the activity of caspases-3, which further aided in increasing apoptosis. Most importantly, EtOH-LCa decreased NF-κB expression (p < 0.05) along with modulating mRNA expression of pro-/anti-apoptotic genes; Bax, Bad, Bcl-2 and Bcl-XL within NSCLC A549 cells. Collectively, it could be concluded that EtOH-LCa possessed considerable anti-cancer effects against NSCLC A549 cells; however, further molecular studies are warranted to completely establish the chemotherapeutical potential of EtOH-LCa.