bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of Lubrication Performances of Vegetable Oils by Genetic Functional Approximation Algorithm
Authors: Liu Jianfang , Zhang Yaoyun , Yang Sicheng , Yi Chenglingzi , Liu Ting , Zhang Rongrong , Jia Dan , Peng Shuai , Yang Qing
Published: June 2024

Vegetable oils, which are considered potential lubricants, are composed of different types and proportions of fatty acids. Because of their diverse types and varying compositions, they exhibit different lubrication performances. The genetic function approximation algorithm was used to model the quantitative structure–property relationship between fatty acid structure and the wear scar diameter and friction coefficients measured by four-ball friction and wear tests. Based on the models with adjusted R2 greater than 0.9 and fatty acid compositions of vegetable oils, the wear scar diameter and friction coefficients of Xanthoceras sorbifolia bunge oil and Soybean oil as validation oil samples were predicted. The difference between the predicted and experimental values was small, indicating that the models could accurately predict the lubrication performances of vegetable oils. The lubrication performances of 14 kinds of vegetable oils were predicted by GFA-QSPR models, and the primary factors influencing their lubrication properties were studied by cluster analysis. The results show that the content of C18:1 has a positive effect on the lubrication performances of vegetable oils, while the content of C18:3 has a negative effect, and the length of the carbon chain of fatty acids significantly affects their lubrication properties.
A Phenomenological Model for Estimating the Wear of Horizontally Straight Slurry Discharge Pipes: A Case Study
Authors: Li Xinggao , Guo Yidong , Li Xingchun , Liu Hongzhi , Yang Yi , Fang Yingran
Published: June 2024

When a slurry TBM advances in pebble and rock strata, large rock particles are carried in pipelines out of a tunnel by moving slurry. To estimate the wear of horizontally straight slurry discharge pipes, a phenomenological model was proposed that was mainly based on knowledge gained by means of direct and indirect in situ observations. The proposed model applies an equation composed of three variables, namely, the wear rate (λ), the central angle (2α), and the excavated tunnel length (L), to estimate the wear distribution along a pipe’s internal surface. The results indicated that wear mainly occurred on the bottoms of pipes. In addition, linear relationships between the maximum pipe wear amount (δmax) and the excavated tunnel length (L) were found for specific pipes and specified types of ground. The observed wear rates of different pipes in different types of ground had varied constants. The wear rates were higher for pipes in rock ground than for those in a pebble layer. For horizontally straight pipes, the observed wear rates were 0.0045 mm/m in a pebble layer and 0.0212 mm/m in rock ground. Lastly, to improve the proposed model, more field monitoring will be necessary to determine the pipe wear rates in different types of ground in the future.
A Fault Prediction Method for CNC Machine Tools Based on SE-ResNet-Transformer
Authors: Wu Zhidong , He Liansheng , Wang Wei , Ju Yongzhi , Guo Qiang
Published: June 2024

Aiming at the problem that predicted data do not reflect the operating status of computer numerical control (CNC) machine tools, this article proposes a new combined model based on SE-ResNet and Transformer for CNC machine tool failure prediction. Firstly, the Transformer model is utilised to build a non-linear temporal feature mapping using the attention mechanism in multidimensional data. Secondly, the predicted data are transformed into 2D features by the SE-ResNet model, which is adept at processing 2D data, and the spatial feature relationships between predicted data are captured, thus enhancing the state recognition capability. Through experiments, data involving the CNC machine tools in different states are collected to build a dataset, and the method is validated. The SE-ResNet-Transformer model can accurately predict the state of CNC machine tools with a recognition rate of 98.56%. Results prove the effectiveness of the proposed method in CNC machine tool failure prediction. The SE-ResNet-Transformer model is a promising approach for CNC machine tool failure prediction. The method shows great potential in improving the accuracy and efficiency of CNC machine tool failure prediction. Feasible methods are provided for precise control of the state of CNC machine tools.
Multivariate Universal Local Linear Kernel Estimators in Nonparametric Regression: Uniform Consistency
Authors: Linke Yuliana , Borisov Igor , Ruzankin Pavel , Kutsenko Vladimir , Yarovaya Elena , Shalnova Svetlana
Published: June 2024

In this paper, for a wide class of nonparametric regression models, new local linear kernel estimators are proposed that are uniformly consistent under close-to-minimal and visual conditions on design points. These estimators are universal in the sense that their designs can be either fixed and not necessarily satisfying the traditional regularity conditions, or random, while not necessarily consisting of independent or weakly dependent random variables. With regard to the design elements, only dense filling of the regression function domain with the design points without any specification of their correlation is assumed. This study extends the dense data methodology and main results of the authors’ previous work for the case of regression functions of several variables.
Fuzzy-Augmented Model Reference Adaptive PID Control Law Design for Robust Voltage Regulation in DC–DC Buck Converters
Authors: Saleem Omer , Ahmad Khalid Rasheed , Iqbal Jamshed
Published: June 2024

This paper presents a novel fuzzy-augmented model reference adaptive voltage regulation strategy for the DC–DC buck converters to enhance their resilience against random input variations and load-step transients. The ubiquitous proportional-integral-derivative (PID) controller is employed as the baseline scheme, whose gains are tuned offline via a pre-calibrated linear-quadratic optimization scheme. However, owing to the inefficacy of the fixed-gain PID controller against parametric disturbances, it is retrofitted with a model reference adaptive controller that uses Lyapunov gain adaptation law for the online modification of PID gains. The adaptive controller is also augmented with an auxiliary fuzzy self-regulation system that acts as a superior regulator to dynamically update the adaptation rates of the Lyapunov gain adaptation law as a nonlinear function of the system’s classical error and its normalized acceleration. The proposed fuzzy system utilizes the knowledge of the system’s relative rate to execute better self-regulation of the adaptation rates, which in turn, flexibly steers the adaptability and response speed of the controller as the error conditions change. The propositions above are validated by performing tailored hardware experiments on a low-power DC–DC buck converter prototype. The experimental results validate the improved reference tracking and disturbance rejection ability of the proposed control law compared to the fixed PID controller.
A Multi-Criteria Assessment Model for Cooperative Technology Transfer Projects from Universities to Industries
Authors: Xiong Rui , Sun Hongyi , Zheng Shufen , Liu Sichu
Published: June 2024

Cooperative Technology Transfer (CTT) is a technology transfer model where universities and enterprises jointly participate throughout the entire process of technology transfer activities. Most discussions focus on its mechanisms and influencing factors, yet a framework to guide CTT projects in practice is still lacking. This study proposes an assessment model based on the life-cycle of CTT projects, covering the initial cooperation relationship, project management during the mid-term, and technological achievements at the end. The model was evaluated by 14 experts first and then validated through two CTT projects in China. Gray Relation Analysis was employed to calculate the weights of different factors based on their relative importance, while the Dempster–Shafer theory was utilized to combine evidence from various sources and address the uncertainty in the assessment. The results of the case analysis indicate that the attitudes of universities and enterprises are considered critical in influencing the success of CTT projects, while management issues that arise during the projects can pose potential risks. This research serves as an applied exploration and has three functions. Firstly, the model can be used as a feasibility study before the project commences. Secondly, it can be utilized to analyze and improve potential issues during the project. Finally, it can be used for a post-project experience summary.
On Hyperbolic Equations with a Translation Operator in Lowest Derivatives
Authors: Vasilyev Vladimir , Zaitseva Natalya
Published: June 2024

In the half-plane, a solution to a two-dimensional hyperbolic equation with a translation operator in the lowest derivative with respect to a spatial variable varying along the entire real axis is constructed in an explicit form. It is proven that the solutions obtained are classical if the real part of the symbol of a differential-difference operator in the equation is positive.
Dynamics for a Ratio-Dependent Prey–Predator Model with Different Free Boundaries
Authors: Liu Lingyu , Li Xiaobo , Li Pengcheng
Published: June 2024

In this paper, we study the dynamics of the ratio-dependent type prey–predator model with different free boundaries. The two free boundaries, determined by prey and predator, respectively, implying that they may intersect with each other as time evolves, are used to describe the spreading of prey and predator. Our primary focus lies in analyzing the long-term behaviors of both predator and prey. We establish sufficient conditions for the spreading and vanishing of prey and predator. Furthermore, in cases where spread occurs, we offer estimates for the asymptotic spreading speeds of prey and predator, denoted as u and v, respectively, as well as the asymptotic speeds of the free boundaries, denoted by h and g. Our findings reveal that when the predator’s speed is lower than that of the prey, it leads to a reduction in the prey’s asymptotic speed.
A Complex-Valued Stationary Kalman Filter for Positive and Negative Sequence Estimation in DER Systems
Authors: Pérez-Ibacache Ricardo , Carvajal Rodrigo , Herrera-Hernández Ramón , Agüero Juan C. , Silva César A.
Published: June 2024

In medium- and low-voltage three-phase distribution networks, the load imbalance among the phases may compromise the network voltage symmetry. Inverter-interfaced distributed energy resources (DERs) can contribute to compensating for such imbalances by sharing the required negative sequence current while providing active power synchronized with the positive sequence voltage. However, positive and negative sequences are conventionally defined in a steady state and are not directly observed from the instantaneous voltage and current measurements at the DER unit’s point of connection. In this article, an estimation algorithm for sequence separation based on the Kalman filter is proposed. Furthermore, the proposed filter uses a complex vector representation of the asymmetric three-phase signals in synchronous coordinates to allow for the implementation of the Kalman filter in its stationary form, resulting in a simple dynamic filter able to estimate positive and negative sequences even during transient operation. The proposed stationary complex Kalman filter performs better than state-of-the-art techniques like DSOGI and very similarly to other Kalman filter implementations found in the literature but at a fraction of its computational cost (23.5%).
A Hybrid Reproducing Kernel Particle Method for Three-Dimensional Helmholtz Equation
Authors: Peng Piaopiao , Wang Ning , Cheng Yumin
Published: June 2024

The reproducing kernel particle method (RKPM) is one of the most universal meshless methods. However, when solving three-dimensional (3D) problems, the computational efficiency is relatively low because of the complexity of the shape function. To overcome this disadvantage, in this study, we introduced the dimension splitting method into the RKPM to present a hybrid reproducing kernel particle method (HRKPM), and the 3D Helmholtz equation is solved. The 3D Helmholtz equation is transformed into a series of related two-dimensional (2D) ones, in which the 2D RKPM shape function is used, and the Galerkin weak form of these 2D problems is applied to obtain the discretized equations. In the dimension-splitting direction, the difference method is used to combine the discretized equations in all 2D domains. Three example problems are given to illustrate the performance of the HRKPM. Moreover, the numerical results show that the HRKPM can improve the computational efficiency of the RKPM significantly.
Bayesian Control Chart for Number of Defects in Production Quality Control
Authors: Supharakonsakun Yadpirun
Published: June 2024

This study investigates the extension of the c-chart control chart to Bayesian methodology, utilizing the gamma distribution to establish control limits. By comparing the performance of the Bayesian approach with that of two existing methods (the traditional frequentist method and the Bayesian with Jeffreys method), we assess its effectiveness in terms of the average run lengths (ARLs) and false alarm rates (FARs). Simulation results indicate that the proposed Bayesian method consistently outperforms the existing techniques, offering larger ARLs and smaller FARs that closely approximate the expected nominal values. While the Bayesian approach excels in most scenarios, challenges may arise with large values of the λ parameter, necessitating adjustments to the hyperparameters of the gamma prior. Specifically, smaller values of the rate parameter are recommended for optimal performance. Overall, our findings suggest that the Bayesian extension of the c-chart provides a promising alternative for enhanced process monitoring and control.
Research on Vehicle AEB Control Strategy Based on Safety Time–Safety Distance Fusion Algorithm
Authors: Fu Xiang , Wan Jiaqi , Wu Daibing , Jiang Wei , Ma Wang , Yang Tianqi
Published: June 2024

With the increasing consumer focus on automotive safety, Autonomous Emergency Braking (AEB) systems, recognized as effective active safety technologies for collision avoidance and the mitigation of collision-related injuries, are gaining wider application in the automotive industry. To address the issues of the insufficient working reliability of AEB systems and their unsatisfactory level of accordance with the psychological expectations of drivers, this study proposes an optimized second-order Time to Collision (TTC) safety time algorithm based on the motion state of the preceding vehicle. Additionally, the study introduces a safety distance algorithm derived from an analysis of the braking process of the main vehicle. The safety time algorithm focusing on comfort and the safety distance algorithm focusing on safety are effectively integrated in the time domain and the space domain to obtain the safety time–safety distance fusion algorithm. A MATLAB/Simulink–Carsim joint simulation platform has been established to validate the AEB control strategy in terms of safety, comfort, and system responsiveness. The simulation results show that the proposed safety time–safety distance fusion algorithm consistently achieves complete collision avoidance, indicating a higher safety level for the AEB system. Furthermore, the application of active hierarchical braking minimizes the distance error, at under 0.37 m, which meets psychological expectations of drivers and improves the comfort of the AEB system.
A Rumor Propagation Model Considering Media Effect and Suspicion Mechanism under Public Emergencies
Authors: Yang Shan , Liu Shihan , Su Kaijun , Chen Jianhong
Published: June 2024

In this paper, we collect the basic information data of online rumors and highly topical public opinions. In the research of the propagation model of online public opinion rumors, we use the improved SCIR model to analyze the characteristics of online rumor propagation under the suspicion mechanism at different propagation stages, based on considering the flow of rumor propagation. We analyze the stability of the evolution of rumor propagation by using the time-delay differential equation under the punishment mechanism. In this paper, the evolution of heterogeneous views with different acceptance and exchange thresholds is studied, using the standard Deffuant model and the improved model under the influence of the media, to analyze the evolution process and characteristics of rumor opinions. Based on the above results, it is found that improving the recovery rate is better than reducing the deception rate, and increasing the eviction rate is better than improving the detection rate. When the time lag τ < 110, it indicates that the spread of rumors tends to be asymptotic and stable, and the punishment mechanism can reduce the propagation time and the maximum proportion of deceived people. The proportion of deceived people increases with the decrease in the exchange threshold, and the range of opinion clusters increases with the decline in acceptance.
Characterization and Metabolism of Drug Products Containing the Cocaine-Like New Psychoactive Substances Indatraline and Troparil
Authors: Manier Sascha K. , Mumber Paula , Zapp Josef , Eckstein Niels , Meyer Markus R.
Published: June 2024

With a rising demand of cocaine over the last years, it is likely that unregulated new psychoactive substances with similar effects such as indatraline ((1R,3S)-3-(3,4-dichlorophenyl)-N-methyl-2,3-dihydro-1H-inden-1-amine) and troparil (Methyl (1R,2S,3S,5S)-8-methyl-3-phenyl-8-azabicyclo[3.2.1]octane-2-carboxylate) become popular as well. Both substances share a similar pharmacological profile as cocaine, while their potency is higher, and their duration of action is longer. This study investigated their metabolic fate in rat urine and incubations using pooled human liver S9 fraction (pHLS9). Indatraline formed two phase I and four phase II metabolites, with aromatic hydroxylation and glucuronidation being the main metabolic steps. All metabolites were detected in rat urine, while the parent compound was not detectable. Although low in abundance, indatraline metabolites were well identifiable due to their specific isotopic patterns caused by chlorine. Troparil formed four phase I and three phase II metabolites, with demethylation being the main metabolic step. Hydroxylation of the tropane ring, the phenyl ring, and combinations of these steps, as well as glucuronidation, were found. Phase I metabolites were detectable in rat urine and pHLS9, while phase II metabolites were only detectable in rat urine.
The Impact of Weight Cycling on Health and Obesity
Authors: Wang Huan , He Wenbi , Yang Gaoyuan , Zhu Lin , Liu Xiaoguang
Published: June 2024

Obesity is a systemic and chronic inflammation, which seriously endangers people’s health. People tend to diet to control weight, and the short-term effect of dieting in losing weight is significant, but the prognosis is limited. With weight loss and recovery occurring frequently, people focus on weight cycling. The effect of weight cycling on a certain tissue of the body also has different conclusions. Therefore, this article systematically reviews the effects of body weight cycling on the body and finds that multiple weight cycling (1) increased fat deposition in central areas, lean mass decreased in weight loss period, and fat mass increased in weight recovery period, which harms body composition and skeletal muscle mass; (2) enhanced the inflammatory response of adipose tissue, macrophages infiltrated into adipose tissue, and increased the production of pro-inflammatory mediators in adipocytes; (3) blood glucose concentration mutation and hyperinsulinemia caused the increase or decrease in pancreatic β-cell population, which makes β-cell fatigue and leads to β-cell failure; (4) resulted in additional burden on the cardiovascular system because of cardiovascular rick escalation. Physical activity combined with calorie restriction can effectively reduce metabolic disease and chronic inflammation, alleviating the adverse effects of weight cycling on the body.
A Genomics-Based Discovery of Secondary Metabolite Biosynthetic Gene Clusters in the Potential Novel Strain Streptomyces sp. 21So2-11 Isolated from Antarctic Soil
Authors: Du Yu , Han Wei , Hao Puyu , Hu Yongqiang , Hu Ting , Zeng Yinxin
Published: June 2024

Streptomyces species are attractive sources of secondary metabolites that serve as major sources of antibiotics and other drugs. In this study, genome mining was used to determine the biosynthetic potential of Streptomyces sp. 21So2-11 isolated from Antarctic soil. 16S rRNA gene sequencing revealed that this strain is most closely related to Streptomyces drozdowiczii NBRC 101007T, with a similarity of 98.02%. Genome comparisons based on average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) showed that strain 21So2-11 represents a novel species of the genus Streptomyces. In addition to a large number of genes related to environmental adaptation and ecological function, a total of 28 putative biosynthetic gene clusters (BGCs) responsible for the biosynthesis of known and/or novel secondary metabolites, including terpenes, lantipeptides, polyketides, nonribosomal peptides, RiPPs and siderophores, were detected in the genome of strain 21So2-11. In addition, a total of 1456 BGCs were predicted to contribute to the biosynthesis of more than 300 secondary metabolites based on the genomes of 47 Streptomyces strains originating from polar regions. The results indicate the potential of Streptomyces sp. 21So2-11 for bioactive secondary metabolite production and are helpful for understanding bacterial adaptability and ecological function in cold terrestrial environments.
Diagnostic Performance of a Molecular Assay in Synovial Fluid Targeting Dominant Prosthetic Joint Infection Pathogens
Authors: Lee Jiyoung , Baek Eunyoung , Ahn Hyesun , Park Heechul , Lee Suchan , Kim Sunghyun
Published: June 2024

Prosthetic joint infection (PJI) is one of the most serious complications of joint replacement surgery among orthopedic surgeries and occurs in 1 to 2% of primary surgeries. Additionally, the cause of PJIs is mostly bacteria from the Staphylococcus species, accounting for more than 98%, while fungi cause PJIs in only 1 to 2% of cases and can be difficult to manage. The current gold-standard microbiological method of culturing synovial fluid is time-consuming and produces false-negative and -positive results. This study aimed to identify a novel, accurate, and convenient molecular diagnostic method. The DreamDX primer–hydrolysis probe set was designed for the pan-bacterial and pan-fungal detection of DNA from pathogens that cause PJIs. The sensitivity and specificity of DreamDX primer–hydrolysis probes were 88.89% (95% CI, 56.50–99.43%) and 97.62% (95% CI, 87.68–99.88%), respectively, compared with the microbiological method of culturing synovial fluid, and receiver operating characteristic (ROC) area under the curve (AUC) was 0.9974 (*** p < 0.0001). It could be concluded that the DreamDX primer–hydrolysis probes have outstanding potential as a molecular diagnostic method for identifying the causative agents of PJIs, and that host inflammatory markers are useful as adjuvants in the diagnosis of PJIs.
The Role of Short-Chain Fatty Acids, Particularly Butyrate, in Oncological Immunotherapy with Checkpoint Inhibitors: The Effectiveness of Complementary Treatment with Clostridium butyricum 588
Authors: Cazzaniga Massimiliano , Cardinali Marco , Di Pierro Francesco , Zonzini Giordano Bruno , Palazzi Chiara Maria , Gregoretti Aurora , Zerbinati Nicola , Guasti Luigina , Matera Maria Rosaria , Cavecchia Ilaria , Bertuccioli Alexander
Published: June 2024

The discovery of immune checkpoints (CTLA-4, PD-1, and PD-L1) and their impact on the prognosis of oncological diseases have paved the way for the development of revolutionary oncological treatments. These treatments do not combat tumors with drugs “against” cancer cells but rather support and enhance the ability of the immune system to respond directly to tumor growth by attacking the cancer cells with lymphocytes. It has now been widely demonstrated that the presence of an adequate immune response, essentially represented by the number of TILs (tumor-infiltrating lymphocytes) present in the tumor mass decisively influences the response to treatments and the prognosis of the disease. Therefore, immunotherapy is based on and cannot be carried out without the ability to increase the presence of lymphocytic cells at the tumor site, thereby limiting and nullifying certain tumor evasion mechanisms, particularly those expressed by the activity (under positive physiological conditions) of checkpoints that restrain the response against transformed cells. Immunotherapy has been in the experimental phase for decades, and its excellent results have made it a cornerstone of treatments for many oncological pathologies, especially when combined with chemotherapy and radiotherapy. Despite these successes, a significant number of patients (approximately 50%) do not respond to treatment or develop resistance early on. The microbiota, its composition, and our ability to modulate it can have a positive impact on oncological treatments, reducing side effects and increasing sensitivity and effectiveness. Numerous studies published in high-ranking journals confirm that a certain microbial balance, particularly the presence of bacteria capable of producing short-chain fatty acids (SCFAs), especially butyrate, is essential not only for reducing the side effects of chemoradiotherapy treatments but also for a better response to immune treatments and, therefore, a better prognosis. This opens up the possibility that favorable modulation of the microbiota could become an essential complementary treatment to standard oncological therapies. This brief review aims to highlight the key aspects of using precision probiotics, such as Clostridium butyricum, that produce butyrate to improve the response to immune checkpoint treatments and, thus, the prognosis of oncological diseases.
Hunting Dynamics and Identification of Potentially Pathogenic Bacteria in European Fallow Deer (Dama dama) across Three Hunting Reserves in Western Romania
Authors: Bucur Iulia-Maria , Moza Alex Cristian , Pop Mirel , Nichita Ileana , Gaspar Cristina Mirabela , Cojocaru Răzvan , Gros Radu-Valentin , Boldea Marius Valentin , Tirziu Andreea , Tirziu Emil
Published: June 2024

The study focused on the hunting practices and potentially pathogenic bacterial species among European fallow deer (Dama dama). Within a five-year period, three hunting grounds from Western Romania were examined. During this period, a total of 1881 deer were hunted, and 240 samples were collected by rectal and nasal swabbing from 120 carcasses. Bacterial strains were identified utilizing bacteriological assays and the Vitek® 2 Compact system. Notably, the Socodor hunting ground exhibited a significant difference in harvesting quotas between the bucks (Group M) and does/yearlings (Group F), favoring the latter. In the Chișineu Criș–Sălișteanca hunting ground, a likely correlation in harvesting quotas between the two groups was observed. The identified potentially pathogenic bacteria were Escherichia coli, Salmonella spp., Staphylococcus aureus, Listeria monocytogenes and Enterococcus faecium. These results highlight the importance of effectively managing the deer population and recognize the potential for Dama dama to spread zoonotic pathogens, emphasizing the necessity of adopting a One Health approach and maintaining ongoing surveillance of this game species’ population dynamics.
Canine Bacterial Endocarditis: A Text Mining and Topics Modeling Analysis as an Approach for a Systematic Review
Authors: Previti Annalisa , Biondi Vito , Passantino Annamaria , Or Mehmet Erman , Pugliese Michela
Published: June 2024

Bacterial endocarditis (BE) is a severe infection of the endocardium and cardiac valves caused by bacterial agents in dogs. Diagnosis of endocarditis is challenging due to the variety of clinical presentations and lack of definitive diagnostic tests in its early stages. This study aims to provide a research literature analysis on BE in dogs based on text mining (TM) and topic analysis (TA) identifying dominant topics, summarizing their temporal trend, and highlighting any possible research gaps. A literature search was performed utilizing the Scopus® database, employing keywords pertaining to BE to analyze papers published in English from 1990 to 2023. The investigation followed a systematic approach based on the PRISMA guidelines. A total of 86 records were selected for analysis following screening procedures and underwent descriptive statistics, TM, and TA. The findings revealed that the number of records published per year has increased in 2007 and 2021. TM identified the words with the highest term frequency-inverse document frequency (TF-IDF), and TA highlighted the main research areas, in the following order: causative agents, clinical findings and predisposing factors, case reports on endocarditis, outcomes and biomarkers, and infective endocarditis and bacterial isolation. The study confirms the increasing interest in BE but shows where further studies are needed.
Exploring the CO2 Electrocatalysis Potential of 2D Metal–Organic Transition Metal–Hexahydroxytriquinoline Frameworks: A DFT Investigation
Authors: Wen Yufeng , Jiang Daguo , Lai Zhangli , Zeng Xianshi , Liu Bo , Xiao Yanan , Ruan Wen , Xiong Kai
Published: June 2024

Metal–organic frameworks have demonstrated great capacity in catalytic CO2 reduction due to their versatile pore structures, diverse active sites, and functionalization capabilities. In this study, a novel electrocatalytic framework for CO2 reduction was designed and implemented using 2D coordination network-type transition metal–hexahydroxytricyclic quinazoline (TM–HHTQ) materials. Density functional theory calculations were carried out to examine the binding energies between the HHTQ substrate and 10 single TM atoms, ranging from Sc to Zn, which revealed a stable distribution of metal atoms on the HHTQ substrate. The majority of the catalysts exhibited high selectivity for CO2 reduction, except for the Mn–HHTQ catalysts, which only exhibited selectivity at pH values above 4.183. Specifically, Ti and Cr primarily produced HCOOH, with corresponding 0.606 V and 0.236 V overpotentials. Vanadium produced CH4 as the main product with an overpotential of 0.675 V, while Fe formed HCHO with an overpotential of 0.342 V. Therefore, V, Cr, Fe, and Ti exhibit promising potential as electrocatalysts for carbon dioxide reduction due to their favorable product selectivity and low overpotential. Cu mainly produces CH3OH as the primary product, with an overpotential of 0.96 V. Zn primarily produces CO with a relatively high overpotential of 1.046 V. In contrast, catalysts such as Sc, Mn, Ni, and Co, among others, produce multiple products simultaneously at the same rate-limiting step and potential threshold.
Advancements in Characterization Techniques for Microemulsions: From Molecular Insights to Macroscopic Phenomena
Authors: Li Longfei , Qu Jiepeng , Liu Weidong , Peng Baoliang , Cong Sunan , Yu Haobo , Zhang Biao , Li Yingying
Published: June 2024

Microemulsions are thermodynamically stable, optically isotropic, transparent, or semi-transparent mixed solutions composed of two immiscible solvents stabilized by amphiphilic solutes. This comprehensive review explores state-of-the-art techniques for characterizing microemulsions, which are versatile solutions essential across various industries, such as pharmaceuticals, food, and petroleum. This article delves into spectroscopic methods, nuclear magnetic resonance, small-angle scattering, dynamic light scattering, conductometry, zeta potential analysis, cryo-electron microscopy, refractive index measurement, and differential scanning calorimetry, examining each technique’s strengths, limitations, and potential applications. Emphasizing the necessity of a multi-technique approach for a thorough understanding, it underscores the importance of integrating diverse analytical methods to unravel microemulsion structures from molecular to macroscopic scales. This synthesis provides a roadmap for researchers and practitioners, fostering advancements in microemulsion science and its wide-ranging industrial applications.
Superluminal Molecular and Nanomaterial Probes Based on Fast Ions or Electrons
Authors: Morrison Alexander , Srivatsa Vashista Muralidhara , Ghandi Khashayar
Published: June 2024

This work reviews the progression of chemical analysis via Cherenkov emissions, i.e., Cherenkov Photometry and Cherenkov Emission Spectroscopy, from its introduction in the literature up to modern developments. In presenting the history of this field, we aim to consolidate the literature, both for reference and contextualization. We present an argument aiming to untangle why this corner of research has seen little progress while so many other directly related aspects of Cherenkov research have flourished, as well as speak to the progress of the field in recent years and prospective direction in years to come.
Selective Adsorption of Sr(II) from Aqueous Solution by Na3FePO4CO3: Experimental and DFT Studies
Authors: Xie Yudong , Wang Xiaowei , Men Jinfeng , Zhu Min , Liang Chengqiang , Ding Hao , Du Zhihui , Bao Ping , Hu Zhilin
Published: June 2024

The efficient segregation of radioactive nuclides from low-level radioactive liquid waste (LLRW) is paramount for nuclear emergency protocols and waste minimization. Here, we synthesized Na3FePO4CO3 (NFPC) via a one-pot hydrothermal method and applied it for the first time to the selective separation of Sr2+ from simulated LLRW. Static adsorption experimental results indicated that the distribution coefficient Kd remained above 5000 mL·g−1, even when the concentration of interfering ions was more than 40 times that of Sr2+. Furthermore, the removal efficiency of Sr2+ showed no significant change within the pH range of 4 to 9. The adsorption of Sr2+ fitted the pseudo-second-order kinetic model and the Langmuir isotherm model, with an equilibrium time of 36 min and a maximum adsorption capacity of 99.6 mg·g−1. Notably, the adsorption capacity was observed to increment marginally with an elevation in temperature. Characterization analyses and density functional theory (DFT) calculations elucidated the adsorption mechanism, demonstrating that Sr2+ initially engaged in an ion exchange reaction with Na+. Subsequently, Sr2+ coordinated with four oxygen atoms on the NFPC (100) facet, establishing a robust Sr-O bond via orbital hybridization.
The Potential of Cold Atmospheric Pressure Plasmas for the Direct Degradation of Organic Pollutants Derived from the Food Production Industry
Authors: Cyganowski Piotr , Terefinko Dominik , Motyka-Pomagruk Agata , Babinska-Wensierska Weronika , Khan Mujahid Ameen , Klis Tymoteusz , Sledz Wojciech , Lojkowska Ewa , Jamroz Piotr , Pohl Pawel , Caban Magda , Magureanu Monica , Dzimitrowicz Anna
Published: June 2024

Specialized chemicals are used for intensifying food production, including boosting meat and crop yields. Among the applied formulations, antibiotics and pesticides pose a severe threat to the natural balance of the ecosystem, as they either contribute to the development of multidrug resistance among pathogens or exhibit ecotoxic and mutagenic actions of a persistent character. Recently, cold atmospheric pressure plasmas (CAPPs) have emerged as promising technologies for degradation of these organic pollutants. CAPP-based technologies show eco-friendliness and potency for the removal of organic pollutants of diverse chemical formulas and different modes of action. For this reason, various types of CAPP-based systems are presented in this review and assessed in terms of their constructions, types of discharges, operating parameters, and efficiencies in the degradation of antibiotics and persistent organic pollutants. Additionally, the key role of reactive oxygen and nitrogen species (RONS) is highlighted. Moreover, optimization of the CAPP operating parameters seems crucial to effectively remove contaminants. Finally, the CAPP-related paths and technologies are further considered in terms of biological and environmental effects associated with the treatments, including changes in antibacterial properties and toxicity of the exposed solutions, as well as the potential of the CAPP-based strategies for limiting the spread of multidrug resistance.
Preliminary Screening on Antibacterial Crude Secondary Metabolites Extracted from Bacterial Symbionts and Identification of Functional Bioactive Compounds by FTIR, HPLC and Gas Chromatography–Mass Spectrometry
Authors: Chandrakasan Gobinath , García-Trejo Juan Fernando , Feregrino-Pérez Ana Angelica , Aguirre-Becerra Humberto , García Enrique Rico , Nieto-Ramírez María Isabel
Published: June 2024

Secondary metabolites, bioactive compounds produced by living organisms, can unveil symbiotic relationships in nature. In this study, soilborne entomopathogenic nematodes associated with symbiotic bacteria (Xenorhabdus stockiae and Photorhabdus luminescens) were extracted from solvent supernatant containing secondary metabolites, demonstrating significant inhibitory effects against E. coli, S. aureus, B. subtilus, P. mirabilis, E. faecalis, and P. stutzeri. The characterization of these secondary metabolites by Fourier transforms infrared spectroscopy revealed amine groups of proteins, hydroxyl and carboxyl groups of polyphenols, hydroxyl groups of polysaccharides, and carboxyl groups of organic acids. Furthermore, the obtained crude extracts were analyzed by high-performance liquid chromatography for the basic identification of potential bioactive peptides. Gas chromatography–mass spectrometry analysis of ethyl acetate extracts from Xenorhabdus stockiae identified major compounds including nonanoic acid derivatives, proline, paromycin, octodecanal derivatives, trioxa-5-aza-1-silabicyclo, 4-octadecenal, methyl ester, oleic acid, and 1,2-benzenedicarboxylicacid. Additional extraction from Photorhabdus luminescens yielded functional compounds such as indole-3-acetic acid, phthalic acid, 1-tetradecanol, nemorosonol, 1-eicosanol, and unsaturated fatty acids. These findings support the potential development of novel natural antimicrobial agents for future pathogen suppression.
Synthesis of Substituted 1,2-Dihydroisoquinolines by Palladium-Catalyzed Cascade Cyclization–Coupling of Trisubstituted Allenamides with Arylboronic Acids
Authors: Yoshida Masahiro , Imaji Ryunosuke , Shiomi Shinya
Published: June 2024

1,2-Dihydroisoquinolines are important compounds due to their biological and medicinal activities, and numerous approaches to their synthesis have been reported. Recently, we reported a facile synthesis of trisubstituted allenamides via N-acetylation followed by DBU-promoted isomerization, where various substituted allenamides were conveniently synthesized from readily available propargylamines with high efficiency. In light of this research background, we focused on the utility of this methodology for the synthesis of substituted 1,2-dihydroisoquinolines. In this study, a palladium-catalyzed cascade cyclization–coupling of trisubstituted allenamides containing a bromoaryl moiety with arylboronic acids is described. When N-acetyl diphenyl-substituted trisubstituted allenamide and phenylboronic acid were treated with 10 mol% of Pd(OAc)2, 20 mol% of P(o-tolyl)3, and 5 equivalents of NaOH in dioxane/H2O (4/1) at 80 °C, the reaction proceeded to afford a substituted 1,2-dihydroisoquinoline. The reaction proceeded via intramolecular cyclization, followed by transmetallation with the arylboronic acid of the resulting allylpalladium intermediate. A variety of highly substituted 1,2-dihydroisoquinolines were concisely obtained using this methodology because the allenamides, as reaction substrates, were prepared from readily available propargylamines in one step.
Halogenated Boroxine K2[B3O3F4OH] Modulates Metabolic Phenotype and Autophagy in Human Bladder Carcinoma 5637 Cell Line
Authors: Elez-Burnjaković Nikolina , Pojskić Lejla , Haverić Anja , Lojo-Kadrić Naida , Hadžić Omanović Maida , Smajlović Ajla , Kalaydjiev Svetoslav , Maksimović Milka , Joksimović Bojan , Haverić Sanin
Published: June 2024

Halogenated boroxine K2[B3O3F4OH] (HB), an inorganic derivative of cyclic anhydride of boronic acid, is patented as a boron-containing compound with potential for the treatment of both benign and malignant skin changes. HB has effectively inhibited the growth of several carcinoma cell lines. Because of the growing interest in autophagy induction as a therapeutic approach in bladder carcinoma (BC), we aimed to assess the effects of HB on metabolic phenotype and autophagy levels in 5637 human bladder carcinoma cells (BC). Cytotoxicity was evaluated using the alamar blue assay, and the degree of autophagy was determined microscopically. Mitochondrial respiration and glycolysis were measured simultaneously. The relative expression of autophagy-related genes BECN1, P62, BCL-2, and DRAM1 was determined by real-time PCR. HB affected cell growth, while starvation significantly increased the level of autophagy in the positive control compared to the basal level of autophagy in the untreated negative control. In HB-treated cultures, the degree of autophagy was higher compared to the basal level, and metabolic phenotypes were altered; both glycolysis and oxidative phosphorylation (OXPHOS) were decreased by HB at 0.2 and 0.4 mg/mL. Gene expression was deregulated towards autophagy induction and expansion. In conclusion, HB disrupted the bioenergetic metabolism and reduced the intracellular survival potential of BC cells. Further molecular studies are needed to confirm these findings and investigate their applicative potential.
Rapid Determination of Tetracyclines in Drinking and Environmental Waters Using Fully Automatic Solid-Phase Extraction with Ultra-Performance Liquid Chromatography–Tandem Mass Spectrometry
Authors: Zhang Tongtong , Zhang Xiangyang , Yu Jiangmei , Hu Hongmei , He Pengfei , Li Zhenhua , Fang Yi , Li Tiejun , Guo Yuanming
Published: June 2024

The abuse and irrational use of tetracyclines (TCs) in human medicine and animal husbandry has become a serious concern, affecting the ecological environment and human health. The aim of this study was to develop a sensitive and selective method using fully automatic solid-phase extraction coupled with ultra-performance liquid chromatography–tandem mass spectrometry for the determination of twelve TCs in water. Four isotope-labeled internal standards for TCs were used to correct matrix effects. Several parameters affecting extraction efficiency were systematically optimized, and the optimum experimental conditions found were 1.0 L water sample with 0.5 g/L Na2EDTA (pH 3.0) extracted and enriched by CNW HLB cartridge and eluted by 4 mL of acetone:methanol (v/v, 1:1). The enrichment factors were up to 798−1059 but only requiring about 60 min per six samples. Under the optimized conditions, the linearity of the method ranged from 0.2 to 100 μg/L for 12 TCs, the detection limits were as low as 0.01−0.15 ng/L, and the recoveries were in the range of 70%–118%, with relative standard deviations less than 15%. The developed method can be successfully utilized for the determination of 12 TCs in pure water, tap water, river water, and mariculture seawater. In summary, three and six TCs were detected in river water and mariculture seawater, respectively, with total concentrations of 0.074–0.520 ng/L (mean 0.248 ng/L) and 0.792–58.369 ng/L (12.629 ng/L), respectively. Tetracycline (TC) and oxytetracycline (OTC) were the dominant TCs in river water, while doxytetracycline (DXC) and OTC were dominant in mariculture seawater.
Polarization and Incident Angle Independent Multifunctional and Multiband Tunable THz Metasurface Based on VO2
Authors: Iqbal Rehmat , Qureshi Ubaid Ur Rahman , Jie Cao , Rahman Zia Ur , Jafar Naveed
Published: June 2024

Aiming at the limitations of single-functionality, limited-applicability, and complex designs prevalent in current metasurfaces, we propose a terahertz multifunctional and multiband tunable metasurface utilizing a VO2-metal hybrid structure. This metasurface structure comprises a top VO2-metal resonance layer, a middle polyimide dielectric layer, and a gold film reflective layer at the bottom. This metasurface exhibits multifunctionality, operating independently of polarization and incident angle. The varying conductivity states of the VO2 layers, enabling the metasurface to achieve various terahertz functionalities, including single-band absorption, broadband THz absorption, and multiband perfect polarization conversion for linear (LP) and circularly polarized (CP) incident waves. Finally, we believe that the functional adaptability of the proposed metasurface expands the repertoire of options available for future terahertz device designs.
Enhancing Optical and Thermal Stability of Blue-Emitting Perovskite Nanocrystals through Surface Passivation with Sulfonate or Sulfonic Acid Ligands
Authors: Huang Shu-Han , Yang Sheng-Hsiung , Tsai Wen-Cheng , Hsu Hsu-Cheng
Published: June 2024

This study aims to enhance the optical and thermal properties of cesium-based perovskite nanocrystals (NCs) through surface passivation with organic sulfonate (or sulfonic acid) ligands. Four different phenylated ligands, including sodium β-styrenesulfonate (SbSS), sodium benzenesulfonate (SBS), sodium p-toluenesulfonate (SPTS), and 4-dodecylbenzenesulfonic acid (DBSA), were employed to modify blue-emitting CsPbBr1.5Cl1.5 perovskite NCs, resulting in improved size uniformity and surface functionalization. Transmission electron microscopy and X-ray photoelectron spectroscopy confirmed the successful anchoring of sulfonate or sulfonic acid ligands on the surface of perovskite NCs. Moreover, the photoluminescence quantum yield increased from 32% of the original perovskite NCs to 63% of the SPTS-modified ones due to effective surface passivation. Time-resolved photoluminescence decay measurements revealed extended PL lifetimes for ligand-modified NCs, indicative of reduced nonradiative recombination. Thermal stability studies demonstrated that the SPTS-modified NCs retained nearly 80% of the initial PL intensity when heated at 60 °C for 10 min, surpassing the performance of the original NCs. These findings emphasize the optical and thermal stability enhancement of cesium-based perovskite NCs through surface passivation with suitable sulfonate ligands.