bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study of Surface Microtexture Formed by Laser-Induced Cavitation Bubble on 7050 Aluminum Alloy
Authors: Li Bin , Min Byung-Won , Ma Yingxian , Zhou Rui , Gu Hai , Cao Yupeng
Published: September 2024

In order to study the feasibility of forming microtexture at the surface of 7050 aluminum alloy by laser-induced cavitation bubble, and how the density of microtexture influences its tribological properties, the evolution of the cavitation bubble was captured by a high-speed camera, and the underwater acoustic signal of evolution was collected by a fiber optic hydrophone system. This combined approach was used to study the effect of the cavitation bubble on 7050 aluminum alloy. The surface morphology of the microtexture was analyzed by a confocal microscope, and the tribological properties of the microtexture were analyzed by a friction testing machine. Then the feasibility of the preparation process was verified and the optimal density was obtained. The study shows that the microtexture on the surface of a sample is formed by the combined results of the plasma shock wave and the collapse shock wave. When the density of microtexture is less than or equal to 19.63%, the diameters of the micropits range from 478 μm to 578 μm, and the depths of the micropits range from 13.56 μm to 18.25 μm. This shows that the laser-induced cavitation bubble is able to form repeatable microtexture. The friction coefficient of the sample with microtexture is lower than that of the untextured sample, with an average friction coefficient of 0.16. This indicates that the microtexture formed by laser-induced cavitation bubble has a good lubrication effect. The sample with a density of 19.63% is uniform and smooth, having the minimum friction coefficient, with an average friction coefficient of 0.14. This paper provides a new approach for microtexture processing of metal materials.
Plasma Spraying NiCoCrAlY-Cr2O3-AgMo Coatings: Fabrication and Tribological Mechanisms
Authors: Zhao Yafei , Gao Yanping , Zhai Zhaoyang , Zhang Yanchao , Zhang Dongya
Published: September 2024

The increasing demand for high-performance aircraft engines has led to a greater emphasis being placed on advanced sealing coating technologies. Developing long-life, self-lubricating, and wear-resistant coatings is of significant research value. This study focuses on the fabrication of a novel self-lubricating and wear-resistant NiCoCrAlY-Cr2O3-AgMo composite coating. This coating was deposited onto a GH4169 substrate utilizing plasma spraying. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD) methods were employed to characterize the elemental composition and microstructure of the fabricated NiCoCrAlY-Cr2O3-AgMo composite coating. Microhardness measurements across the coating cross-section indicated a gradual increase in hardness from the GH4169 substrate to the NiCoCrAlY-Cr2O3-AgMo coating. The average hardness of the GH4169 substrate was 413.92 HV0.2, while the CoNiCrAlY bonding layer region exhibited an average hardness of 467.60 HV0.2. The NiCoCrAlY-Cr2O3-AgMo coating itself demonstrated an average microhardness of 643.22 HV0.2. Room temperature friction tests indicated that the average coefficient of friction (COF) of the GH4169 substrate was 0.665. In contrast, the NiCoCrAlY-Cr2O3-AgMo coating exhibited a significantly lower average COF of 0.16, representing a 75.94% reduction compared to the uncoated GH4169 substrate. High-temperature friction tests were conducted at 400 °C, 500 °C, and 600 °C, indicating average COF values of 0.438, 0.410, and 0.268, respectively, for the NiCoCrAlY-Cr2O3-AgMo coating. Specifically, at 600 °C, the formation of a lubricious NiMoO4 tribofilm on the coating surface was observed. This tribofilm effectively reduced the wear rate of the GH605 pin to 2.78 × 10−6 mm3/N·m, highlighting the potential of the NiCoCrAlY-Cr2O3-AgMo coating to reduce wear in high-temperature sliding contact applications.
Structure and Mechanical Properties of Microwave-Absorbing Co-C Coatings Obtained by Magnetron Sputtering
Authors: Prokhorenkova Nadezhda , Zhilkashinova Almira , Abilev Madi , Ocheredko Igor , Pavlov Alexandr , Mussabekova Altynay , Kuanyshbekov Tilek , Zhilkashinova Assel
Published: September 2024

This article is devoted to the study of microwave-absorbing properties of Co-C coating applied by magnetron sputtering. This article presents the main results of the manufacturing of a Co-C coating by magnetron sputtering, and the evaluation of experimental and computational research data on the relationship between the structure and properties of the obtained films. The structure of Co-C systems has been modeled to control the resulting structures using X-ray diffraction analysis. The structural-phase state of the resulting thin-film Co-C systems and the microwave-absorbing properties of coatings were studied using the transmission line method, consisting of a vector network analyzer, an air coaxial line, a software program, and an external computer. It has been established that on the resulting Co-C film the reflection coefficient in the frequency range of 8.2–12.4 GHz varies in the range of 900 → 718 mU, with reflection losses of −0.86 → −2.57 dB, and a standing wave coefficient of 19 → 6.8. An analysis of the obtained data indicates the presence of losses of electromagnetic energy in the studied frequency range.
Machine Learning to Predict Workability and Compressive Strength of Low- and High-Calcium Fly Ash–Based Geopolymers
Authors: Harmaji Andrie , Kirana Mira Chandra , Jafari Reza
Published: September 2024

The potential substitution of Portland cement–based concrete with low- and high-calcium fly ash–based geopolymers was investigated. However, predicting the workability and compressive strength of geopolymers with the desired physical and mechanical properties is a complicated process because of the variety of chemical compositions found in aluminosilicate sources. Therefore, machine-learning techniques were used to predict the physical and mechanical properties of the geopolymers and eliminate the usual trial-and-error laboratory procedures. The experimental and predicted results of geopolymer properties using the multilayer perceptron regressor, voting regressor, and XGBoost techniques were compared. The XGBoost model outperformed the other models in terms of accuracy for predicting workability and compressive strength, producing the R2 of 0.96 and 0.89, respectively. Sensitivity analysis determined that the percentage of CaO had the largest effect on geopolymer workability of 27.13%. Fly ash content had the largest effect on compressive strength of 34.44%. Our approach offers a straightforward and dependable strategy for designing and optimizing fly ash–based geopolymers.
Mastery of the Concept of Percentage and Its Representations in Finnish Comprehensive School Grades 7–9
Authors: Joutsenlahti Jorma , Perkkilä Päivi
Published: September 2024

This research was conducted in 2019 in collaboration with Japanese colleagues, with the research tasks translated from the original Japanese. In Finland, a total of 1112 students from grades 7–9 in primary school participated in the study. In our article, we examine Finnish students’ mastery of the concept of percentages and how they express their mathematical thinking about percentages in a multimodal way. A multimodal expression of mathematical thinking can typically take the form of natural language, written mathematics, pictorial representations, mathematical symbolic language, or combinations of these, which can be used to manage information, such as through tables. Our focus is on Finnish primary-school students’ mastery of the concept of percentages, and we then narrow our analysis to tasks where students have used a multimodal approach. We analyze the representations of the concept of percentages and the related thought processes. The concept of percentages was best mastered in grade 9 and weakest in grade 7. Students mostly used a combination of pictorial language, natural language, and mathematical symbolic language to describe their solution processes. However, describing their thinking in different ways did not necessarily highlight possible errors in their reasoning.
Research on Solid-State Linear Transformer Driver Power Source Driving Atmospheric Pressure Plasma Jet Treatment of Epoxy Resin
Authors: Cao Xiangnan , Song Guiying , Chen Yikai , Chen Haowei
Published: September 2024

The Solid-State Linear Transformer Driver (SSLTD) is a nanosecond pulse power source characterized by its fast rise time and adjustable output waveform. It can generate uniform and stable atmospheric plasma jets, which is suitable for material surface modification. In this study, a 15-stage SSLTD was designed and assembled, which can produce a stable nanosecond pulse voltage up to 15 times the amplitude of the charging voltage at high frequencies, with a rise time of approximately 10 ns. This device can be used to generate stable atmospheric pressure Ar plasma jets with an electron density in the range of 1015~1016 cm−3 and gas temperatures close to room temperature. After the modification treatment by the plasma jets, the content of the C=O groups on the surface of the epoxy resin significantly increased in the wavelength range of 1720~1740 cm−1, and its flashover resistance was noticeably enhanced. The optimal comprehensive modification effect was achieved at a charging voltage of 600 V, pulse width of 50 ns, and pulse frequency in the range of 800~1000 Hz.
Diversity of Birch and Alder Forests in the Kostanay Region of Kazakhstan
Authors: Koblanova Saule , Mukhtubayeva Saule , Kakimzhanova Almagul , Orazov Aidyn , Dyussembekova Damira , Abileva Gulmira
Published: September 2024

This study delves into the phytocenotic structure and biodiversity of forest ecosystems dominated by species of the family Betulaceae (Betula pendula, Betula pubescens, and Alnus glutinosa) in the Kostanay region of Kazakhstan. The research is a significant step toward understanding the influence of environmental factors, particularly hydrological regimes and soil conditions, on the formation and functioning of these forest communities. Field studies were conducted across multiple plots, where detailed geobotanical descriptions and analyses of species diversity were performed. The results underscore the significant species diversity, with 146 vascular plant species identified across various forest types, and are of great importance. Birch forests exhibit higher species diversity than alder forests, with the highest diversity observed in plots with favourable moisture conditions. The study concludes that the hydrological regime is critical in shaping these forest ecosystems’ phytocenotic structure and productivity. These conclusions underline the importance of biodiversity conservation and sustainable forest management in the region, making the implications of this research significant and far reaching.
Housing Initiatives to Address Strep A Infections and Reduce RHD Risks in Remote Indigenous Communities in Australia
Authors: Lansbury Nina , Memmott Paul C. , Wyber Rosemary , Burgen Clarissa , Barnes Samuel K. , Daw Jessica , Cannon Jeffrey , Bowen Asha C. , Burgess Rachel , Frank Patricia N. , Redmond Andrew M.
Published: September 2024

Group A Streptococcus (Strep A) skin infections (impetigo) can contribute to the development of acute rheumatic fever (ARF) and rheumatic heart disease (RHD). This is of particular concern for Indigenous residents of remote communities, where rates of ARF and RHD are much higher than their urban and non-Indigenous counterparts. There are three main potential Strep A transmission pathways: skin to skin, surface to skin, and transmission through the air (via droplets or aerosols). Despite a lack of scientific certainty, the physical environment may be modified to prevent Strep A transmission through environmental health initiatives in the home, identifying a strong role for housing. This research sought to provide an outline of identified household-level environmental health initiatives to reduce or interrupt Strep A transmission along each of these pathways. The identified initiatives addressed the ability to wash bodies and clothes, to increase social distancing through improving the livability of yard spaces, and to increase ventilation in the home. To assist with future pilots and evaluation, an interactive costing tool was developed against each of these initiatives. If introduced and evaluated to be effective, the environmental health initiatives are likely to also interrupt other hygiene-related infections.
Indoor Air Quality at an Urban Primary School in Madrid (Spain): Influence of Surrounding Environment and Occupancy
Authors: Alonso-Blanco Elisabeth , Gómez-Moreno Francisco Javier , Díaz-Ramiro Elías , Barreiro Marcos , Fernández Javier , Figuero Ibai , Rubio-Juan Alejandro , Santamaría Jesús Miguel , Artíñano Begoña
Published: September 2024

Monitoring indoor air quality (IAQ) in schools is critical because children spend most of their daytime inside. One of the main air pollutant sources in urban areas is road traffic, which greatly influences air quality. Thus, this study addresses, in depth, the linkages of meteorology, ambient air pollution, and indoor activities with IAQ in a traffic-influenced school situated south of Madrid. The measurement period was from 22 November to 21 December 2017. Simultaneous measurements of indoor and outdoor PM1, PM2.5, and PM10 mass concentrations, ultrafine particle number concentration (PNC) and equivalent black carbon (eBC) were analyzed under different meteorological conditions. PNC and eBC outdoor concentrations and their temporal trend were similar among the sampling points, with all sites being influenced in the same way by traffic emissions. Strong correlations were found between indoor and outdoor concentrations, indicating that indoor pollution levels were significantly affected by outdoor sources. Especially, PNC and eBC had the same indoor/outdoor (I/O) trend, but indoor concentrations were lower. The time delay in indoor vs. outdoor concentrations varied between 0.5 and 2 h, depending on wind speed. Significant differences were found between different meteorological conditions (ANOVA p-values < 2.14 × 10−6). Atmospheric stability periods led to an increase in indoor and outdoor pollutant levels. However, the highest I/O ratios were found during atmospheric instability, especially for eBC (an average of 1.2). This might be related to rapid changes in the outdoor air concentrations induced by meteorology. Significant variations were observed in indoor PM10 concentrations during classroom occupancy (up to 230 µg m−3) vs. non-occupancy (up to 19 µg m−3) days, finding levels higher than outdoor ones. This was attributed to the scholarly activities in the classroom. Conversely, PNC and eBC concentrations only increased when the windows of the classroom were open. These findings have helped to establish practical recommendations and measures for improving the IAQ in this school and those of similar characteristics.
Flower Visitation through the Lens: Exploring the Foraging Behaviour of Bombus terrestris with a Computer Vision-Based Application
Authors: Varga-Szilay Zsófia , Szövényi Gergely , Pozsgai Gábor
Published: September 2024

To understand the processes behind pollinator declines and for the conservation of pollination services, we need to understand fundamental drivers influencing pollinator behaviour. Here, we aimed to elucidate how wild bumblebees interact with three plant species and investigated their foraging behaviour with varying flower densities. We video-recorded Bombus terrestris in 60 × 60 cm quadrats of Lotus creticus, Persicaria capitata, and Trifolium pratense in urban areas of Terceira (Azores, Portugal). For the automated bumblebee detection and counting, we created deep learning-based computer vision models with custom datasets. We achieved high model accuracy of 0.88 for Lotus and Persicaria and 0.95 for Trifolium, indicating accurate bumblebee detection. In our study, flower cover was the only factor that influenced the attractiveness of flower patches, and plant species did not have an effect. We detected a significant positive effect of flower cover on the attractiveness of flower patches for flower-visiting bumblebees. The time spent per unit of inflorescence surface area was longer on the Trifolium than those on the Lotus and Persicaria. However, our result did not indicate significant differences in the time bumblebees spent on inflorescences among the three plant species. Here, we also justify computer vision-based analysis as a reliable tool for studying pollinator behavioural ecology.
Repellent Effects of Coconut Fatty Acid Methyl Esters and Their Blends with Bioactive Volatiles on Winged Myzus persicae (Sulzer) Aphids (Hemiptera: Aphididae)
Authors: Martín Félix , Guirao Pedro , Pascual-Villalobos María Jesús
Published: September 2024

Myzus persicae (Sulzer) (Hemiptera: Aphididae) is one of the most important aphid crop pests, due to its direct damage and its ability to transmit viral diseases in crops. The objective is to test whether spraying nanoemulsions of botanical products repels winged individuals of M. persicae in a bioassay in culture chambers. The bioactive volatiles were applied on pepper plants at a dose of 0.2% alone or at 0.1% of each component in blends. A treated plant and a control plant were placed at each side of an entomological cage inside a growth chamber. The winged individuals were released between the plants, in a black-painted Petri dish suspended by wires in the upper half of the cage. The most repellent products were farnesol (repellency index, RI = 40.24%), (E)-anethole (RI = 30.85%) and coconut fatty acid methyl ester (coconut FAME) (RI = 28.93%), alone or in the following blends: farnesol + (E)-anethole + distilled lemon oil (RI = 36.55%) or (E)-anethole + distilled lemon oil + coconut FAME (RI = 30.63%). The observed effect of coconut FAME on aphids is the first report of this product having a repellent effect on a crop pest. Repellent substances for viral disease vectors should be further investigated to develop new strategies for plant protection.
Osseointegration of Dental Implants after Vacuum Plasma Surface Treatment In Vivo
Authors: Kahm Se Hoon , Lee Sang Hwa , Lim Youbong , Jeon Hyun Jeong , Yun Kyoung-In
Published: September 2024

Previous studies have highlighted the need for post-treatment of implants due to surface aging. This study investigated the effect of vacuum plasma (VP) treatment on the osseointegration of sandblasted, large grit, acid-etched (SLA) implant surfaces. The hypothesis was that VP might enhance implant stability, measured by implant stability quotient (ISQ) and histological osseointegration through bone-to-implant contact (BIC) and bone area ratio (BA) in rabbit models. Eighteen implants were either untreated or treated with VP and installed into the femurs of six rabbits, which were sacrificed after four weeks. Histological analyses of BIC and BA, along with micro-CT analysis of bone volume and ISQ, were performed. The VP-treated group showed higher levels of BA, bone volume, and ISQ, but no statistically significant differences were observed between the control and experimental groups. Despite limitations, both groups achieved better osseointegration and regeneration, warranting further studies on plasma treatment effects over varying implantation periods.
A Privacy-Preserving and Quality-Aware User Selection Scheme for IoT
Authors: Han Bing , Fu Qiang , Su Hongyu , Chi Cheng , Zhang Chuan , Wang Jing
Published: September 2024

In the Internet of Things (IoT), the selection of mobile users with IoT-enabled devices plays a crucial role in ensuring the efficiency and accuracy of data collection. The reputation of these mobile users is a key indicator in selecting high-quality participants, as it directly reflects the reliability of the data they submit and their past performance. However, existing approaches often rely on a trusted centralized server, which can lead to single points of failure and increased vulnerability to attacks. Additionally, they may not adequately address the potential manipulation of reputation scores by malicious entities, leading to unreliable and potentially compromised user selection. To address these challenges, we propose PRUS, a privacy-preserving and quality-aware user selection scheme for IoT. By leveraging the decentralized and immutable nature of the blockchain, PRUS enhances the reliability of the user selection process. The scheme utilizes a public-key cryptosystem with distributed decryption to protect the privacy of users’ data and reputation, while truth discovery techniques are employed to ensure the accuracy of the collected data. Furthermore, a privacy-preserving verification algorithm using reputation commitment is developed to safeguard against the malicious tampering of reputation scores. Finally, the Dirichlet distribution is used to predict future reputation values, further improving the robustness of the selection process. Security analysis demonstrates that PRUS effectively protects user privacy, and experimental results indicate that the scheme offers significant advantages in terms of communication and computational efficiency.
Valorization of the Invasive Blue Crabs (Callinectes sapidus) in the Mediterranean: Nutritional Value, Bioactive Compounds and Sustainable By-Products Utilization
Authors: Arena Rosaria , Renda Giuseppe , Ottaviani Aalmo Giovanna , Debeaufort Frédéric , Messina Concetta Maria , Santulli Andrea
Published: September 2024

The blue crab (Callinectes sapidus), originally from the western Atlantic Ocean, has recently spread to the Mediterranean and is now considered one of the one hundred most invasive species in that region. This opportunistic species, known for its adaptability to different temperatures and salinities, negatively impacts biodiversity and human activities such as fishing and tourism in the Mediterranean. However, the blue crab is gaining interest as a potential food resource due to its high nutritional value and delicate, sweet flavor. Its meat is rich in protein (14% to 30%), omega-3 fatty acids (EPA and DHA) and other essential nutrients beneficial for human health such as vitamins, and minerals. Utilizing this species in the production of new foods could help mitigate the negative impact of its invasiveness and offer economic opportunities. One challenge with this potential resource is the generation of waste. Approximately 6–8 million tonnes of crab shells are produced worldwide each year, leading to disposal problems and concerns regarding environmental sustainability. To improve economic and environmental sustainability, there is a need to valorize these residues, which are an important source of proteins, lipids, chitin, minerals, and pigments that can be processed into high-value-added products. However, especially in areas with industrial pollution, attention should be paid to the heavy metal (Cd and As) contents of blue crab shells. Studies suggest that blue crab by-products can be used in various sectors, reducing environmental impacts, promoting a circular economy, and creating new industrial opportunities.
Optimizing Wear Resistance and Tensile Strength of Nickel-Based Coatings through Tungsten Carbide Reinforcement
Authors: Zhang Li , Li Shengli , Zhang Chunlin , Zhang Shihan , Ai Xingang , Xie Zhiwen
Published: September 2024

While the addition of WC increases the hardness and wear resistance of coatings, an excessive WC content can also induce crack initiation and propagation, increasing brittleness and leading to premature failure. Therefore, in this study, WC particles were incorporated into nickel-based coatings by plasma-arc surfacing to optimize their content and distribution, balancing their tensile properties and wear resistance. The coatings were comprehensively evaluated through microstructural analysis, hardness testing, wear resistance assessment, and tensile testing. The results show that as the mass fraction of WC increased from 45% to 65%, the increase in carbon significantly promoted the formation of M7C3, M6C, and M23C6 carbides and suppressed the formation of the γ-phase. The microstructural analysis showed that the content of massive carbides increased significantly with the increasing WC content, and the XPS analysis further confirmed that the changes in the WC and Cr7C3 phases were particularly pronounced in the high-WC coating. The 65% WC coating showed higher hardness (a 232 increase in HV1.0), a lower and more stable coefficient of friction (0.42), and better wear resistance than the 45% WC coating, with a wear rate of 3.329 × 10−6 mm3/(N·m)−1, which was 3.709 × 10−6 mm3/(N·m)−1 lower than that of the 45% WC coating. The conventional tensile test results show that the maximum stress and strain of the 45% WC coating were 71% and 36% higher than those of the 65% WC coating, respectively. In addition, the 45% WC coating exhibited better ductility and quasi-cleavage characteristics, whereas the 65% WC coating showed typical brittle cracking behavior. The results of the field tensile tests also showed that the fracture time of the 65% WC coating was 27 s shorter than that of the 45% WC coating. Overall, the 45% WC coating had a good combination of strength and toughness.
Properties Investigation and Damage Analysis of GaN Photoconductive Semiconductor Switch Based on SiC Substrate
Authors: Xu Jiankai , Jiang Lijuan , Cai Ping , Feng Chun , Xiao Hongling , Wang Xiaoliang
Published: September 2024

The GaN photoconductive semiconductor switches (PCSSs) with low leakage current and large on-state current are suitable for several applications, including fast switching and high-power electromagnetic pulse equipment. This paper demonstrates a high-power GaN lateral PCSS device. An output peak current of 142.2 A is reached with an input voltage of 10.28 kV when the GaN lateral PCSS is intrinsically triggered. In addition, the method of retaining the AlGaN/GaN heterostructure between electrodes on PCSSs is proposed, which results in increasing the output peak current of the PCSS. The damage mechanism of the PCSS caused by a high electric field and high excitation laser energy is analyzed. The obtained results show that the high heat generated by the large current leads to the decomposition of GaN, and thus, the Ga forms a metal conductive path, resulting in the failure of the device.
Thermo-Convective Solution Growth of Vertically Aligned Zinc Oxide Nanowire Arrays for Piezoelectric Energy Harvesting
Authors: Anang Frank Eric Boye , Refino Andam Deatama , Harm Gunilla , Li Defang , Xu Jiushuai , Cain Markys , Brand Uwe , Li Zhi , Görke Marion , Garnweitner Georg , Peiner Erwin
Published: September 2024

The search for a synthesis method to create longer ZnO NWAs with high-quality vertical alignment, and the investigation of their electrical properties, have become increasingly important. In this study, a hydrothermal method for growing vertically aligned arrays of ZnO nanowires (NWs) using localized heating was utilized. To produce longer NWs, the temperature environment of the growth system was optimized with a novel reaction container that provided improved thermal insulation. At a process temperature above ~90 °C, ZnO NWs reached a length of ~26.8 µm within 24 h, corresponding to a growth rate of 1.1 µm/h, nearly double the rate of 0.6 µm/h observed in traditional chemical bath growth using a glass reactor. The densely grown NWs (~1.9/µm2), with a diameter of ~0.65 µm, exhibited a preferred hexagonal c-axis orientation and were vertically aligned to the (100) silicon (Si) substrate. These NW structures have multiple applications, e.g., in piezotronic strain sensors, gas sensing, and piezoelectric energy harvesting. As proof of concept, a piezoelectric nanogenerator (PENG) was fabricated by embedding the NWs in an S1818 polymer matrix over a 15 mm × 15 mm area. Under repeated impulse-type compressive forces of 0.9 N, a maximum peak output voltage of ~95.9 mV was recorded, which is higher by a factor of four to five than the peak output voltage of 21.6 mV previously obtained with NWs measuring ~1.8 µm in length.
Quantitative Changes and Transformation Mechanisms of Saponin Components in Chinese Herbal Medicines during Storage and Processing: A Review
Authors: Wu Yuhang , Zheng Hui , Zheng Tao , Jiang Jiani , Xu Yao , Jia Fan , He Kai , Yang Yong
Published: September 2024

Saponins are an important class of active components in Chinese herbal medicines (CHMs), which are present in large quantities in Ginseng Radix et Rhizoma, Notoginseng Radix et Rhizoma, Polygonati Rhizoma, etc., and have immune regulation, anti-tumor, anti-inflammatory, anti-cardiovascular disease, and hypoglycemic activities. Storage and processing are essential processes in the production process of CHMs which affect the stability of saponin components and then reduce the medicinal and economic value. Therefore, it is of great importance to investigate the effects of storage and processing conditions on the content of saponin components in CHMs. In this paper, the effects of various storage and processing factors, including temperature, pH, enzymes, meta lions, extraction methods, etc., on the saponin content of CHMs are investigated and the underlying mechanisms for the quantitative changes of saponin are summarized. These findings may provide technical guidance for the production and processing of saponin-rich CHMs.
Strength of London Dispersion Forces in Organic Structure Directing Agent—Zeolite Assemblies
Authors: Ata Karima , Mineva Tzonka , Alonso Bruno
Published: September 2024

Herein, we study the London dispersion forces between organic structure directing agents (OSDAs)—here tetraalkyl-ammonium or -phosphonium molecules—and silica zeolite frameworks (FWs). We demonstrate that the interaction energy for these dispersion forces is correlated to the number of H atoms in OSDAs, irrespective of the structures of OSDAs or FWs, and of variations in charges and thermal motions. All calculations considered—DFT-D3 and BOMD undertaken by us, and molecular mechanics from an accessible database—led to the same trend. The mean energy of these dispersion forces is ca. −2 kcal.mol−1 per H for efficient H-O contacts.
Towards Nickel–NHC Fluoro Complexes—Synthesis of Imidazolium Fluorides and Their Reactions with Nickelocene
Authors: Wills Siobhan S. , Bailly Corinne , Chetcuti Michael J.
Published: September 2024

While hundreds of complexes of the general formula [Ni(η5-C5H5)(NHC)(X)] exist (NHC = a N-heterocyclic carbene, X = Cl, Br, I), none is yet known with X = F. We attempted to prepare such a species by reacting nickelocene with imidazolium fluorides. Three imidazolium fluorides (ImH)+ F− [Im = (N,N′-bis-(R)-imidazolium: 1a, IMe, R = Me; 1b, IMes, R = 2,4,6-trimethylphenyl; 1c, IPr, R = 2,6-diisopropylphenyl)] were prepared and characterized by spectroscopic methods. In addition, the salts 1b [(IMesH)+ F−] and 1c [(IPrH)+ F−] were subjected single-crystal X-ray diffraction experiments. The reactions of these imidazolium fluorides with nickelocene did not lead to [Ni(η5-C5H5)(NHC)(F)] species. Instead, the reaction of 1a [(IMeH)+ F−] and 1b [(IMesH)+ F−] with nickelocene led to the salt 2 [Ni(η5-C5H5)(IMe)2]+ F− and to the square planar complex 3atrans-[NiF2(IMes)2] respectively. Both complexes were characterized spectroscopically and by single crystal X-ray diffraction. All four X-ray diffraction studies reveal hydrogen bonding and hydrogen interactions with the F atom or anion, and in some cases with solvent molecules of crystallization, and these phenomena are all discussed. Complex 2, in particular, exhibited a wide range of interesting H-bonded interactions in the solid state. Complexes 2 and 3a were tested as catalysts for Suzuki–Miyaura coupling but were not promising: complex 2 was inactive, and while 3a did indeed catalyze the reaction, it gave widely diverging results owing to its instability in solution.
Dynamic Adsorption of Mn2+ from Acid Mine Drainage by Highly Active Immobilized Particles with Fe0/Fe2+ Enhanced SRB
Authors: Chen He , Wang Laigui , An Wenbo , Wang Qiqi
Published: September 2024

Bioremediation of acid mine drainage (AMD) was often challenged by poor tolerance of sulfate-reducing bacteria (SRB) to heavy metals and low bioactivity. The highly active immobilized particles with Fe0/Fe2+ enhanced SRB (Fe0/2+-SRB) were prepared by the microorganism immobilization technique. Three dynamic columns were constructed to investigate the adsorption capacity of Fe0/2+-SRB for Mn2+ under varying adsorption layer heights, inflow velocity, and initial Mn2+ concentrations. The role of each matrix material in the immobilized particles was explored, the mechanism of AMD remediation by Fe0/2+-SRB was revealed, and the adaptability of Fe0/2+-SRB to AMD under various initial conditions was investigated. The results showed that the prepared Fe0/2+-SRB exhibited a well-developed surface pore structure. When the adsorption layer height was 200 mm, the influent flow rate was 5 × 10−5 m3/s, and the initial manganese ion concentration was 10 mg/L, the maximum dynamic adsorption capacities (qe) of Mn2+ for each dynamic column were 7.8430, 4.7627, and 8.7677 mg/g, respectively. Compared to dynamic columns 1# and 2#, dynamic column 3# showed the best performance in treating AMD, and the Thomas model effectively described the adsorption kinetics of Mn2+ by Fe0/2+-SRB(3#). Microstructural analysis indicated that chemical adsorption, ion exchange, dissimilation–reduction reaction, and surface complexation occurred between the various matrix materials in Fe0/2+-SRB(3#). Mn2+ was primarily removed in the form of metal sulfide (MnS), and Fe0/Fe2+ could promote the dissimilatory reduction of SO42− by SRB to form S2−. Fe0/2+-SRB(3#) was able to adapt to AMD with initial conditions of pH was 2~4, SO42− < 2500 mg/L, and Mn2+ < 20 mg/L. The research results provide new insights into the remediation of AMD, using a combined microbial-adsorption technology.
Pharmacokinetics and Dose Proportionality Study of a Novel Antiparkinsonian Agent, a 1H-1,2,4-Triazol-3-ylthio-conjugate of Prottremine
Authors: Gorina Daria S. , Lastovka Anastasiya V. , Rogachev Artem D. , Podturkina Alexandra V. , Pavlova Alla V. , Ardashov Oleg V. , Li-Zhulanov Nikolai S. , Tolstikova Tatyana G. , Volcho Konstantin P. , Salakhutdinov Nariman F.
Published: September 2024

The novel antiparkinsonian agent PA-96 is the focus of our research. PA-96 supported the survival of cultured naïve dopamine neurons, alleviated motor deficits in MPTP and haloperidol-based mice models of Parkinson’s disease, and increased the density of tyrosine hydroxylase positive neurons and dopamine concentration in the midbrain of an MPTP-damaged brain. In this work, an HPLC–MS/MS method was developed and validated, and the pharmacokinetics of the agent was investigated in mice after a single or multiple oral administration (p.o.) and intravenous injection (i.v.) at various doses. The dose proportionality was also evaluated after a single p.o. administration of three ascending doses (1, 5, and 10 mg/kg) and a single i.v. injection of two doses (1 and 10 mg/kg); also, the bioavailability was estimated. The disproportionality of pharmacokinetic parameters could be explained by the saturation of active centres of enzymes or receptors binding the substance: at low doses, part of the compound is bound, leaving a small amount circulating in blood, and rapidly metabolised and/or bound too. The bioavailability of PA-96 was c.a. 7 and 35% for the doses of 5 and 10 mg/kg, correspondingly.
S/N Co-Doped Ultrathin TiO2 Nanoplates as an Anode Material for Advanced Sodium-Ion Hybrid Capacitors
Authors: Li Yuzhu , Lan Qing , Gao Yuanfei , Zhang Dan , Liu Guangyin , Cheng Jinbing
Published: September 2024

Anatase titanium dioxide (TiO2) has emerged as a potential anode material for sodium-ion hybrid capacitors (SICs) in terms of its nontoxicity, high structure stability and cost-effectiveness. However, its inherent poor electrical conductivity and limited reversible capacity greatly hinder its practical application. Here, ultrathin TiO2 nanoplates were synthesized utilizing a hydrothermal technique. The electrochemical kinetics and reversible capacity were significantly improved through sulfur and nitrogen co-doping combined with carbon coating (SN-TiO2/C). Sulfur and nitrogen co-doping generated oxygen vacancies and introduced additional active sites within TiO2, facilitating accelerated Na-ion diffusion and enhancing its reversible capacity. Furthermore, carbon coating provided stable support for electron transfer in SN-TiO2/C during repeated cycling. This synergistic strategy of sulfur and nitrogen co-doping with carbon coating for TiO2 led to a remarkable capacity of 335.3 mAh g−1 at 0.1 A g−1, exceptional rate property of 148.3 mAh g−1 at 15 A g−1 and a robust cycling capacity. Thus, the SN-TiO2/C//AC SIC delivered an impressive energy density of 177.9 W h kg−1. This work proposes an idea for the enhancement of reaction kinetics for energy storage materials through a synergistic strategy.
Cu-ZnO Embedded in a Polydopamine Shell for the Generation of Antibacterial Surgical Face Masks
Authors: d’Alessandro Nicola , Coccia Francesca , Vitali Luca Agostino , Rastelli Giorgia , Cinosi Amedeo , Mascitti Andrea , Tonucci Lucia
Published: September 2024

A new easy protocol to functionalize the middle layer of commercial surgical face masks (FMs) with Zn and Cu oxides is proposed in order to obtain antibacterial personal protective equipment. Zinc and copper oxides were synthesized embedded in a polydopamine (PDA) shell as potential antibacterial agents; they were analyzed by XRD and TEM, revealing, in all the cases, the formation of metal oxide nanoparticles (NPs). PDA is a natural polymer appreciated for its simple and rapid synthesis, biocompatibility, and high functionalization; it is used in this work as an organic matrix that, in addition to stabilizing NPs, also acts as a diluent in the functionalization step, decreasing the metal loading on the polypropylene (PP) surface. The functionalized middle layers of the FMs were characterized by SEM, XRD, FTIR, and TXRF and tested in their bacterial-growth-inhibiting effect against Klebsiella pneumoniae and Staphylococcus aureus. Among all functionalizing agents, Cu2O-doped-ZnO NPs enclosed in PDA shell, prepared by an ultrasound-assisted method, showed the best antibacterial effect, even at low metal loading, without changing the hydrophobicity of the FM. This approach offers a sustainable solution by prolonging FM lifespan and reducing material waste.
Unveiling the Influences of In Situ Carbon Content on the Structure and Electrochemical Properties of MoS2/C Composites
Authors: Zhang Bofeng , Zhao Junyao , Zhang He , Tian Jian , Cui Yang , Zhu Wenjun
Published: September 2024

In this work, a MoS2/C heterostructure was designed and prepared through an in situ composite method. The introduction of carbon during the synthesis process altered the morphology and size of MoS2, resulting in a reduction in the size of the flower-like structures. Further, by varying the carbon content, a series of characterization methods were employed to study the structure and electrochemical lithium storage performance of the composites, revealing the effect of carbon content on the morphology, structure characteristics, and electrochemical performance of MoS2/C composites. The experimental setup included three sample groups: MCS, MCM, and MCL, with glucose additions of 0.24 g, 0.48 g, and 0.96 g, respectively. With increasing carbon content, the size of MoS2 initially decreases, then increases. Among these, the MCM sample exhibits the optimal structure, characterized by smaller MoS2 dimensions with less variation. The electrochemical results showed that MCM exhibited excellent electrochemical lithium storage performance, with reversible specific capacities of 956.8, 767.4, 646.1, and 561.4 mAh/g after 10 cycles at 100, 200, 500, and 1000 mA/g, respectively.
Recent Progress in Regulating the Activity of Enzymes with Photoswitchable Inhibitors
Authors: Chen Yi
Published: September 2024

Photoregulation of biomolecules has become crucial tools in chemical biology, because light enables access under mild conditions and with delicate spatiotemporal control. The control of enzyme activity in a reversible way is a challenge. To achieve it, a facile approach is to use photoswitchable inhibitors. This review highlights recent progress in photoswitchable inhibitors based on azobenzenes units. The progress suggests that the incorporation of an azobenzene unit to a known inhibitor is an effective method for preparing a photoswitchable inhibitor, and with these photoswitchable inhibitors, the activity of enzymes can be regulated by optical control, which is valuable in both basic science and therapeutic applications.
Preparation and Tumor Inhibitory Activity of Tricin from Carex Meyeriana Kunth
Authors: Cui Baiji , Sun Jie , Chang Sheng , Zhang Hongmei , Li Yawei , Feng Xianmin , Guo Zengjun
Published: September 2024

This study describes the purification and preparation of tricin (5, 7, 4-trihydroxy-3, 5-dimethoxyflavone) from Carex Meyeriana Kunth via adsorption and desorption using macroporous resins and high-performance liquid chromatography. Six resins were tested to evaluate the static adsorption and desorption capacities. The HPD-300 resin was selected as the adsorption material to enrich tricin because of its suitable adsorption and desorption capacities. Adsorption thermodynamics and kinetics were studied on HPD-300 resin, and the results agreed with the Langmuir model and quasi-second-order kinetics model, respectively. The parameters of the dynamic adsorption and desorption tests were then optimized. The purity of tricin increased from 2.6 mg/g to 45.1 mg/g with a recovery yield of 76.4% after purification using HPD-300 resin. Then, Prep-HPLC was used to further purify tricin. The purity of tricin reached 99.4%, with a recovery yield of 78.0% thereafter. Tricin exerts an inhibitory effect on the proliferation of various tumor cells, including gastric cancer SGC-7901 cells. It significantly suppresses cell colony formation while also altering cell cycle progression metabolism by decreasing the proportion of cells in the G0/G1 phase and increasing the proportion in the S and G2/M phases. Additionally, tricin affects the efficiency of SGC-7901 cell lactate production, ATP content, and glucose uptake. These findings suggest that tricin may impede tumor cell proliferation through its impact on cell cycle progression and energy metabolism.
Hispidol Regulates Behavioral Responses to Ethanol through Modulation of BK Channels: A Novel Candidate for the Treatment of Alcohol Use Disorder
Authors: Yang Wooin , Goh Hee Jae , Han Young Taek , Lee Myon-Hee , Cha Dong Seok
Published: September 2024

Alcohol use disorder (AUD) is the most common substance use disorder and poses a significant global health challenge. Despite pharmacological advances, no single drug effectively treats all AUD patients. This study explores the protective potential of hispidol, a 6,4′-dihydroxyaurone, for AUD using the Caenorhabditis elegans model system. Our findings demonstrate that hispidol-fed worms exhibited more pronounced impairments in thrashes, locomotory speed, and bending amplitude, indicating that hispidol exacerbated the detrimental effects of acute ethanol exposure. However, hispidol significantly improved ethanol withdrawal behaviors, such as locomotory speed and chemotaxis performance. These beneficial effects were absent in slo-1 worms (the ortholog of mammalian α-subunit of BK channel) but were restored with the slo-1(+) or hslo(+) transgene, suggesting the involvement of BK channel activity. Additionally, hispidol increased fluorescence intensity and puncta in the motor neurons of slo-1::mCherry-tagged worms, indicating enhanced BK channel expression and clustering. Notably, hispidol did not alter internal ethanol concentrations, suggesting that its action is independent of ethanol metabolism. In the mouse models, hispidol treatment also demonstrated anxiolytic activity against ethanol withdrawal. Overall, these findings suggest hispidol as a promising candidate for targeting the BK channel in AUD treatment.
Antitumoral and Antiproliferative Potential of Synthetic Derivatives of Scorpion Peptide IsCT1 in an Oral Cavity Squamous Carcinoma Model
Authors: Cabral Laertty Garcia de Sousa , de Oliveira Cyntia Silva , Oliveira Vani Xavier , Alves Rosely Cabette Barbosa , Poyet Jean-Luc , Maria Durvanei Augusto
Published: September 2024

The oral cavity is a frequent site for head and neck cancers, which rank as the sixth most common cancer globally, with a 5-year survival rate slightly over 50%. Current treatments are limited, and resistance to therapy remains a significant clinical obstacle. IsCT1, a membrane-active peptide derived from the venom of the scorpion Opisthacanthus madagascariensis, has shown antitumor effects in various cancer cell lines, including breast cancer and chronic myeloid leukemia. However, its hemolytic action limits its potential therapeutic use. This study aims to assess the antitumor and antiproliferative activities of synthetic peptides derived from IsCT1 (IsCT-P, AC-AFPK-IsCT1, AFPK-IsCT1, AC-KKK-IsCT1, and KKK-IsCT1) in the context of oral squamous cell carcinoma. We evaluated the cytotoxic effects of these peptides on tongue squamous cell carcinoma cells and normal cells, as well as their impact on cell cycle phases, the expression of proliferation markers, modulators of cell death pathways, and mitochondrial potential. Our results indicate that the IsCT1 derivatives IsCT-P and AC-AFPK-IsCT1 possess cytotoxic properties towards squamous cell carcinoma cells, reducing mitochondrial membrane potential and the proliferative index. The treatment of cancer cells with AC-AFPK-IsCT1 led to a positive modulation of pro-apoptotic markers p53 and caspases 3 and 8, a decrease in PCNA and Cyclin D1 expression, and cell cycle arrest in the S phase. Notably, contrary to the parental IsCT1 peptide, AC-AFPK-IsCT1 did not exhibit hemolytic activity or cytotoxicity towards normal cells. Therefore, AC-AFPK-IsCT1 might be a viable therapeutic option for head and neck cancer treatment.
Electrical Quantum Coupling of Subsurface-Nanolayer Quasipolarons
Authors: Zeng Yihan , Li Ruichen , Fang Shengyu , Hu Yuting , Yang Hongxin , Chen Junhao , Su Xin , Chen Kai , Liu Laijun
Published: September 2024

We perform dielectric and impedance spectrums on the compressively-strained ceramics of multiferroic bismuth ferrite. The subsurface-nanolayer quasipolarons manifest the step-like characteristic of pressure-dependent transient frequency and, furthermore, pressure-dependency fails in the transformation between complex permittivity and electrical impedance, which is well-known in classic dielectric physics, as well as the bulk dipole chain at the end of the dissipation peak.
Before or Concomitant Drinking Greenleaf Juice with Rice Reduces Postprandial Blood Glucose Levels in Healthy Young Women
Authors: Sera Nobuko , Taguchi Fuka , Hanamura Isaki , Hongo Ryoko
Published: September 2024

The purpose of this study was to examine how green leaf juice drinking affect the postprandial blood glucose. Postprandial hyperglycemia causes vascular endothelial damage and chronic inflammation, promoting atherosclerosis, regardless of the presence of diabetes. Some ingredients in greenleaf juice have been reported to suppress blood glucose levels; however, the effect of greenleaf juice on reducing blood glucose levels in healthy individuals is unclear. We observed changes in postprandial blood glucose levels in 13 healthy young women who drank greenleaf juice before or concomitantly with rice. Compared to water, greenleaf juice consumption reduced blood glucose levels at 90 and 120 min after rice consumption, with no difference regardless of the time of greenleaf juice consumption. Greenleaf juice may be one of the most convenient and cost-effective methods for reducing postprandial blood glucose in healthy people.