bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization Techniques in the Localization Problem: A Survey on Recent Advances
Authors: Stefanoni Massimo , Sarcevic Peter , Sárosi József , Odry Akos
Published: August 2024

Optimization is a mathematical discipline or tool suitable for minimizing or maximizing a function. It has been largely used in every scientific field to solve problems where it is necessary to find a local or global optimum. In the engineering field of localization, optimization has been adopted too, and in the literature, there are several proposals and applications that have been presented. In the first part of this article, the optimization problem is presented by considering the subject from a purely theoretical point of view and both single objective (SO) optimization and multi-objective (MO) optimization problems are defined. Additionally, it is reported how local and global optimization problems can be tackled differently, and the main characteristics of the related algorithms are outlined. In the second part of the article, extensive research about local and global localization algorithms is reported and some optimization methods for local and global optimum algorithms, such as the Gauss–Newton method, Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Differential Evolution (DE), and so on, are presented; for each of them, the main concept on which the algorithm is based, the mathematical model, and an example of the application proposed in the literature for localization purposes are reported. Among all investigated methods, the metaheuristic algorithms, which do not exploit gradient information, are the most suitable to solve localization problems due to their flexibility and capability in solving non-convex and non-linear optimization functions.
Using ArcFace Loss Function and Softmax with Temperature Activation Function for Improvement in X-ray Baggage Image Classification Quality
Authors: Andriyanov Nikita
Published: August 2024

Modern aviation security systems are largely tied to the work of screening operators. Due to physical characteristics, they are prone to problems such as fatigue, loss of attention, etc. There are methods for recognizing such objects, but they face such difficulties as the specific structure of luggage X-ray images. Furthermore, such systems require significant computational resources when increasing the size of models. Overcoming the first and second disadvantage can largely lie in the hardware plane. It needs new introscopes and registration techniques, as well as more powerful computing devices. However, for processing, it is more preferable to improve quality without increasing the computational power requirements of the recognition system. This can be achieved on traditional neural network architectures, but with the more complex training process. A new training approach is proposed in this study. New ways of baggage X-ray image augmentation and advanced approaches to training convolutional neural networks and vision transformer networks are proposed. It is shown that the use of ArcFace loss function for the task of the items binary classification into forbidden and allowed classes provides a gain of about 3–5% for different architectures. At the same time, the use of softmax activation function with temperature allows one to obtain more flexible estimates of the probability of belonging, which, when the threshold is set, allows one to significantly increase the accuracy of recognition of forbidden items, and when it is reduced, provides high recall of recognition. The developed augmentations based on doubly stochastic image models allow one to increase the recall of recognizing dangerous items by 1–2%. On the basis of the developed classifier, the YOLO detector was modified and the mAP gain of 0.72% was obtained. Thus, the research results are matched to the goal of increasing efficiency in X-ray baggage image processing.
Effective Methods of Categorical Data Encoding for Artificial Intelligence Algorithms
Authors: Bolikulov Furkat , Nasimov Rashid , Rashidov Akbar , Akhmedov Farkhod , Cho Young-Im
Published: August 2024

It is known that artificial intelligence algorithms are based on calculations performed using various mathematical operations. In order for these calculation processes to be carried out correctly, some types of data cannot be fed directly into the algorithms. In other words, numerical data should be input to these algorithms, but not all data in datasets collected for artificial intelligence algorithms are always numerical. These data may not be quantitative but may be important for the study under consideration. That is, these data cannot be thrown away. In such a case, it is necessary to transfer categorical data to numeric type. In this research work, 14 encoding methods of transforming of categorical data were considered. At the same time, conclusions are given about the general conditions of using these methods. During the research, categorical data in the dataset that were collected in order to assess whether it is possible to give credit to customers will be transformed based on 14 methods. After applying each encoding method, experimental tests are conducted based on the classification algorithm, and they are evaluated. At the end of the study, the results of the experimental tests are discussed and research conclusions are presented.
Dynamic Target Assignment by Unmanned Surface Vehicles Based on Reinforcement Learning
Authors: Hu Tao , Zhang Xiaoxue , Luo Xueshan , Chen Tao
Published: August 2024

Due to the dynamic complexities of the multi-unmanned vessel target assignment problem at sea, especially when addressing moving targets, traditional optimization algorithms often fail to quickly find an adequate solution. To overcome this, we have developed a multi-agent reinforcement learning algorithm. This approach involves defining a state space, employing preferential experience replay, and integrating self-attention mechanisms, which are applied to a novel offshore unmanned vessel model designed for dynamic target allocation. We have conducted a thorough analysis of strike positions and times, establishing robust mathematical models. Additionally, we designed several experiments to test the effectiveness of the algorithm. The proposed algorithm improves the quality of the solution by at least 30% in larger scale scenarios compared to the genetic algorithm (GA), and the average solution speed is less than 10% of the GA, demonstrating the feasibility of the algorithm in solving the problem.
Resistance Pattern of Klebsiella pneumoniae in Aseer Region, Saudi Arabia: A Ten-Year Hospital-Based Study
Authors: Alshehri Saad Mohammed , Abdullah Naif Saud , Algarni Abdullah , AlZomia Ahmed Saad , Assiry Mohammed Mushabub
Published: August 2024

Background and Objectives: The frequency of multidrug-resistant Klebsiella pneumoniae (MDRKP) has dramatically increased worldwide in recent decades, posing an urgent threat to public health. The aim of this study was to assess the extent of K. pneumoniae in the Aseer region and explore the corresponding antimicrobial resistance profile over the last ten years. Materials and Methods: A record-based retrospective study was conducted in a tertiary hospital during the period of 2013 to 2022. The study targeted laboratory samples taken from patients admitted to the hospital and sent for K. pneumoniae culturing. We included only samples taken from the patient and confirmed by the lab. Data were extracted using a pre-structured data extraction sheet to avoid data-collection bias and confirm the inter-rater precision. Statistical Package for Social Sciences (SPSS) version 26 was employed for statistical analysis. All relationships were tested using Pearson X2 test for categorical data or chi-square for linear trend for resistance rate over years. Results: We obtained 3921 samples of isolated K. pneumoniae out of 28,420 bacterial samples. The isolation rate began at 11.3% in 2013, decreased to 6.1% in 2016, and then increased to a peak of 16.3% in 2021, before slightly decreasing to 12.8% in 2022. In total, 23.7% of K. pneumoniae samples were identified in urine samples, 19% in sputum samples, 14% in wound samples, and 11.7% in blood samples. The overall antibiotic resistance rate of K. pneumoniae from 2013 to 2022 showed a significant increase, particularly during 2020 and 2021, before decreasing again in 2022. The resistance rate decreased from 22.2% in 2013 to 18.6% in 2016 and increased to 54.6% and 56.4% during 2020 and 2021, respectively (p = 0.039). Conclusions: We observed a significant shift in K. pneumoniae resistance for some antibiotics during the study period, highlighting the urgent need for enhanced antimicrobial stewardship and infection-control measures.
Exploring Ventilator-Associated Pneumonia: Microbial Clues and Biomarker Insights from a Retrospective Study
Authors: Gouda Ahmed M. , Sileem Ashraf E. , Elnahas Hanan M. , Tawfik Ahmed E. , Eid Refaat A. , Shati Ayed A. , Al-Qahtani Saleh M. , Dawood Samy A. , Alshehri Mohammed A. , Eissa Mohamed , Soltan Mohamed A. , Noreldin Ahmed E. , Elwishahy Amir Helmy , Negm Essamedin M.
Published: August 2024

Background and Objectives: Ventilator-associated pneumonia (VAP) is a common complication in critically ill patients receiving mechanical ventilation. The incidence rates of VAP vary, and it poses significant challenges due to microbial resistance and the potential for adverse outcomes. This study aims to explore the microbial profile of VAP and evaluate the utility of biomarkers and illness severity scores in predicting survival. Materials and Methods: A retrospective cohort study was conducted involving 130 patients diagnosed with VAP. Microbial analysis of bronchoalveolar lavage (BAL) fluid, as well as measurements of C-reactive protein (CRP) and procalcitonin (PCT) levels, were performed. Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores were calculated to assess illness severity. Statistical analyses were conducted to determine correlations and associations. Results: The study revealed that Klebsiella pneumoniae (K. pneumoniae) (50.7%) and Pseudomonas aeruginosa (P. aeruginosa) (27.69%) were the most identified microorganisms in VAP cases. SOFA (p-value < 0.0001) and APACHE II (p-value < 0.0001) scores were effective in assessing the severity of illness and predicting mortality in VAP patients. Additionally, our investigation highlighted the prognostic potential of CRP levels (odds ratio [OR]: 0.980, 95% confidence interval [CI] 0.968 to 0.992, p = 0.001). Elevated levels of CRP were associated with reduced survival probabilities in VAP patients. Conclusion: This study highlights the microbial profile of VAP and the importance of biomarkers and illness severity scores in predicting survival. Conclusions: The findings emphasize the need for appropriate management strategies to combat microbial resistance and improve outcomes in VAP patients.
A Systematic Review of Oral Vertical Dyskinesia (“Rabbit” Syndrome)
Authors: Rissardo Jamir Pitton , Kherajani Krish , Vora Nilofar Murtaza , Yatakarla Venkatesh , Fornari Caprara Ana Letícia , Ratliff Jeffrey , Caroff Stanley N.
Published: August 2024

Background and Objectives: Vertical rhythmic dyskinetic movements that are primarily drug-induced and affect solely the jaw, mouth, and lips without involving the tongue have been historically described as “rabbit” syndrome (RS). Evidence on the unique features and implications of this disorder remains limited. This literature review aims to evaluate the clinical–epidemiological profile, pathological mechanisms, and management of this movement disorder. Materials and Methods: Two reviewers identified and assessed relevant reports in six databases without language restriction published between 1972 and 2024. Results: A total of 85 articles containing 146 cases of RS were found. The mean frequency of RS among adults in psychiatric hospitals was 1.2% (range 0–4.4%). The mean age of affected patients was 49.2 (SD: 17.5), and 63.6% were females. Schizophrenia was the most frequent comorbidity found in 47.6%, followed by bipolar disorder (17.8%), major depressive disorder (10.3%), and obsessive–compulsive disorder (3.7%). Five cases were idiopathic. The most common medications associated with RS were haloperidol (17%), risperidone (14%), aripiprazole (7%), trifluoperazine (5%), and sulpiride (5%). The mean duration of pharmacotherapy before RS was 21.4 weeks (SD: 20.6). RS occurred in association with drug-induced parkinsonism (DIP) in 27.4% and with tardive dyskinesia (TD) in 8.2% of cases. Antipsychotic modification and/or anticholinergic drugs resulted in full or partial recovery in nearly all reported cases in which they were prescribed. Conclusions: RS occurs as a distinct drug-induced syndrome associated primarily but not exclusively with antipsychotics. Distinguishing RS from TD is important because the treatment options for the two disorders are quite different. By contrast, RS may be part of a spectrum of symptoms of DIP with similar course, treatment outcomes, and pathophysiology.
Deceased Donor Uterus Transplantation: A Narrative Review of the First 24 Published Cases
Authors: Pecorino Basilio , Scibilia Giuseppe , Ferrara Martina , Veroux Pierfrancesco , Chiofalo Benito , Scollo Paolo
Published: August 2024

Uterus transplantation is the surgical treatment for absolute uterine factor infertility (AUFI), a congenital or acquired condition characterized by the absence of a uterus. More than 80 transplants have been performed worldwide, resulting in more than 30 live births, originating both from living and deceased donors. The collection of published articles on deceased donor uterus transplantations was performed in PubMed and SCOPUS by searching for the terms “Uterus transplantation” AND “deceased donor”; from the 107 articles obtained, only case reports and systematic reviews of deceased donor uterus transplantations and the resulting live births were considered for the present manuscript. The extracted data included the date of surgery (year), country, recipient (age and cause of AUFI) and donor (age and parity) details, outcome of recipient surgery (hysterectomy), and live births (date and gestational age). The search of peer-reviewed publications showed 24 deceased donor uterus transplantations and 12 live births (a birth rate of 66%) with a 25% occurrence of graft loss during follow-up (6 of 24). Among this series, twelve transplants were performed in the USA (seven births), five in the Czech Republic (one birth), three in Italy (one birth), two in Turkey (two births), and two in Brazil (one birth). The median recipient age was 29.8 years (range 21–36), while the median donor age was 36.1 years (range 20–57). Of 24 recipients, 100% were affected by MRKH (Mayer-Rokitanski-Kuster-Hauser) syndrome. Two live births were reported from nulliparous donors. Deceased donor uterus transplantation birth rates are very similar to the living donor rates reported in the literature, but ethical implications could be less important in the first group. It is necessary to register every case in the International Registry for Uterus Transplantation in order to perform a systematic review and comparison with living donor rates.
Effects of TiAlN Coating Thickness on Machined Surface Roughness, Surface Residual Stresses, and Fatigue Life in Turning Inconel 718
Authors: Jiang Aisheng , Zhao Jinfu , Cui Pengcheng , Liu Zhanqiang , Wang Bing
Published: August 2024

The surface roughness and surface residual stresses are affected by the coating thickness of physical vapor deposition (PVD) TiAlN tools, which could alter the service performance of machined components. However, the relationships among the tool coating thickness, the machined surface roughness, the surface residual stress, and the fatigue life are still not sufficiently illustrated. In this research, PVD TiAlN coatings with several thicknesses of 1.6 μm, 2 μm, 2.5 μm, and 3 μm were deposited on carbide tools. Turning experiments using Inconel 718 were conducted with uncoated and various TiAlN tools under flood cooling conditions. The surface roughness could be improved with the selection of thin PVD TiAlN coating thicknesses of 1.6 μm and 2 μm compared to that of uncoated tools. The tensile residual stresses at the machined surface in the directions of cutting speed and feed rate linearly decreased by 148.67% and exponentially decreased by 92.24% when the TiAlN coating thickness was increased from 0 μm to 3 μm. The values of the low-cycle fatigue life of machined Inconel 718 linearly increased by 15.60% with the increase in TiAlN coating thickness from 0 μm to 3 μm, which was mainly due to the improvement of surface residual stresses. The results could provide guidance for the selection of suitable TiAlN coating thicknesses for wet machining Inconel 718 based on the part service conditions.
Analysis of the Effects of Water Temperature on Water-Assisted Laser Trepanning in Superalloys
Authors: Xia Kaibo , Wang Liang , Li Mingchao , Yang Huayu
Published: August 2024

The water-assisted laser trepanning method has been proven to improve the quality of laser drilling; however, the effect of water temperature on this process is currently unclear. In order to investigate the influence of water temperature on the quality of holes produced via water-assisted laser trepanning in superalloys, this study used the controlled variable method to investigate the effects of three water temperatures—low temperature (2 °C), normal temperature (20 °C), and high temperature (70 °C)—on the following factors: spatter, hole diameter, taper angle, hole sidewall morphology, and recast layer. The results show that the spatter around the hole reduced, the hole entrance/exit diameter increased, and the roughness of the hole’s sidewall decreased with an increase in single-pulse energy. However, the effect of single-pulse energy on the recast layer was not obvious. As the temperature of the water increased, the hole entrance/exit diameter increased, and the roughness of the hole’s sidewall decreased. When the single-pulse energy was 1.0–1.9 J, using a lower water temperature produced a hole with a smaller taper angle. Compared with a water temperature of 20 °C, the movement of the melt film on the hole’s sidewall accelerated when the water temperature was 70 °C; as a result, more molten material could be removed from the hole, resulting in a decrease in the thickness of the recast layer. However, when the water temperature was 2 °C, the heat-affected zone and the thickness of the recast layer decreased more significantly. The results of this study provide technical support for the optimization of water-assisted laser drilling.
A Systematic Review of Modeling and Simulation for Precision Diamond Wire Sawing of Monocrystalline Silicon
Authors: Li Ansheng , Wang Hongyan , Hu Shunchang , Zhou Yu , Du Jinguang , Ji Lianqing , Ming Wuyi
Published: August 2024

Precision processing of monocrystalline silicon presents significant challenges due to its unique crystal structure and chemical properties. Effective modeling and simulation are essential for advancing the understanding of the manufacturing process, optimizing design, and refining production parameters to enhance product quality and performance. This review provides a comprehensive analysis of the modeling and simulation techniques applied in the precision machining of monocrystalline silicon using diamond wire sawing. Firstly, the principles of mathematical analytical model, molecular dynamics, and finite element methods as they relate to monocrystalline silicon processing are outlined. Subsequently, the review explores how mathematical analytical models address force-related issues in this context. Molecular dynamics simulations provide valuable insights into atomic-scale processes, including subsurface damage and stress distribution. The finite element method is utilized to investigate temperature variations and abrasive wear during wire cutting. Furthermore, similarities, differences, and complementarities among these three modeling approaches are examined. Finally, future directions for applying these models to precision machining of monocrystalline silicon are discussed.
Study on 1550 nm Human Eye-Safe High-Power Tunnel Junction Quantum Well Laser
Authors: Wu Qi , Xu Dongxin , Ma Xuehuan , Li Zaijin , Qu Yi , Qiao Zhongliang , Liu Guojun , Zhao Zhibin , Zeng Lina , Chen Hao , Li Lin , Li Lianhe
Published: August 2024

Falling within the safe bands for human eyes, 1550 nm semiconductor lasers have a wide range of applications in the fields of LIDAR, fast-ranging long-distance optical communication, and gas sensing. The 1550 nm human eye-safe high-power tunnel junction quantum well laser developed in this paper uses three quantum well structures connected by two tunnel junctions as the active region; photolithography and etching were performed to form two trenches perpendicular to the direction of the epitaxial layer growth with a depth exceeding the tunnel junction, and the trenches were finally filled with oxides to reduce the extension current. Finally, a 1550 nm InGaAlAs quantum well laser with a pulsed peak power of 31 W at 30 A (10 KHz, 100 ns) was realized for a single-emitter laser device with an injection strip width of 190 μm, a ridge width of 300 μm, and a cavity length of 2 mm, with a final slope efficiency of 1.03 W/A, and with a horizontal divergence angle of about 13° and a vertical divergence angle of no more than 30°. The device has good slope efficiency, and this 100 ns pulse width can be effectively applied in the fields of fog-transparent imaging sensors and fast headroom ranging radar areas.
Nonlinear Optical Response of Au/CsPbI3 Quantum Dots and Its Laser Modulation Characteristics at 2.7 μm
Authors: Lv Mengqi , Zhao Jin , Guo Leilei , Zhang Yanxu , Zhao Qiuling , Teng Lihua , Wang Maorong , Zhang Shuaiyi , Wang Xia
Published: August 2024

A passively Q-switched Er:YAP laser of 2.7 µm, utilizing Au-doped CsPbI3 quantum dots (QDs) as a saturable absorber (SA), was realized. It was operated stably with a minimum pulse width of 185 ns and a maximum repetition rate of 480 kHz. The maximum pulse energy and the maximum peak power were 0.6 μJ and 2.9 W, respectively, in the Q-switched operation. The results show that the CsPbI3 QDs SA exhibits remarkable laser modulation properties at ~3 μm.
Research on the Key Technology of a Fluorescence Detection Device Using the RT-LAMP Method for Instant Detection
Authors: Guo Hongzhuang , Gong Ping , Sun Tingting , Wang Xin , Zhang Hao
Published: August 2024

As of 31 October 2023, there have been 771,795,258 confirmed cases of COVID-19 globally. Developing simple, portable, and reliable testing devices has become increasingly important. This paper presents a point-of-care testing (POCT) device for COVID-19 based on the dual-excitation fluorescence RT-LAMP method, which is derived from the principles of RT-LAMP-based COVID-19 detection kits available in the market. The key design solutions of the device were simulated and modeled. Key performance metrics such as detection repeatability and linearity were validated. Comparative experiments with the RT-qPCR detection method were conducted to verify the accuracy and reliability of the device. Additionally, the device’s detection sensitivity and accuracy were assessed. Experimental results show that the repeatability coefficient of variation (CV) value is ≤0.09%; the linearity R2 for the FAM channel is 0.9977 and that for the HEX channel is 0.9899; it exhibits good anti-interference performance, with negligible cross-channel interference; the temperature stability is ±0.062 °C, the temperature accuracy is less than 0.2 °C, and there is no significant temperature overshoot during the heating process. Compared with the real-time quantitative PCR (RT-qPCR) instrument, the positive agreement rate is 100% and the negative agreement rate is 95.0%. This research provides a foundational basis for the development of equipment for the prevention of infectious diseases and clinical diagnostics.
Development of a Fast Positioning Platform with a Large Stroke Based on a Piezoelectric Actuator for Precision Machining
Authors: Hu Gaofeng , Xin Wendong , Zhang Min , Chen Guangjun , Man Jia , Tian Yanling
Published: August 2024

In this paper, a fast positioning platform (FPP) is proposed, able to meet simultaneously the requirements of large stroke and high frequency response, developed based on a PZT (piezoelectric actuator) and a quad-parallel flexible mechanism, for application in precision machining. The FPP is driven by a high-stiffness PZT and guided by a flexible hinge-based mechanism with a quad-parallel flexible hinge. The proposed quad-parallel flexible hinge mechanism can provide excellent planar motion capability with high stiffness and good guiding performance, thus guaranteeing outstanding dynamics characteristics. The mechanical model was established, the input and output characteristics of the FPP were analyzed, and the working range (output displacement and frequency) of the FPP was determined. Based on the mechanical model and the input and output characteristics of the FPP, the design method is described for of the proposed FPP, which is capable of achieving a large stroke while responding at a high frequency. The characteristics of the FPP were investigated using finite element analysis (FEA). Experiments were conducted to examine the performance of the FPP; the natural frequency of the FPP was 1315.6 Hz, while the maximum output displacement and the motion resolution of the FPP in a static state were 53.13 μm and 5 nm, respectively. Step response testing showed that under a step magnitude of 50 μm, the stabilization times for the falling and rising edges of the moving platform were 37 ms and 26 ms, respectively. The tracking errors were about ±1.96 μm and ±0.59 μm when the amplitude and frequency of the signal were 50 μm, 50 Hz and 10 μm, 200 Hz, respectively. The FPP showed excellent performance in terms of fast response and output displacement. The cutting test results indicated that compared with the uncontrolled condition, the values of surface roughness under controlled conditions decreased by 23.9% and 12.7% when the cutting depths were 5 μm and 10 μm, respectively. The developed FPP device has excellent precision machining performance.
Evaluation of Direct Antimicrobial Susceptibility Testing of Gram-Negative Bacilli and Staphylococcus aureus from Positive Pediatric Blood Culture Bottles Using BD Phoenix M50
Authors: Morales Princess , Tang Patrick , Mariano Elaine , Gopalan Arun , Aji Nisha , Pérez-López Andrés , Suleiman Mohammed
Published: August 2024

Bloodstream infections (BSIs) are life-threatening infections for which a timely initiation of appropriate antimicrobial therapy is critical. Antibiotic susceptibility testing (AST) directly performed on positive blood culture broths can help initiate targeted antibiotic therapy sooner than the standard AST performed on colonies isolated on solid media after overnight incubation. Faster antimicrobial susceptibility testing (AST) results can improve clinical outcomes, and reduce broad-spectrum antimicrobial consumption and healthcare-associated costs in sepsis. In this study, we evaluated the accuracy of a direct AST inoculation method on the BD Phoenix M50 system using serum separator tubes to harvest bacteria from positive pediatric blood culture bottles. Direct AST was performed on 132 monomicrobial pediatric blood culture bottles that were positive for Enterobacterales (65; 49.2%), Staphylococcus aureus (46; 34.8%), and non-fermenting Gram-negative bacilli (21; 16%). Overall, the categorical and essential agreements between the direct method and standard method were 99.6% and 99.8%, respectively. Very major, major, and minor error rates were 0.1%, 0.09%, and 0.20% respectively. Direct AST performed on pediatric blood culture bottles using BD Phoenix M50 can quickly provide accurate susceptibility information to guide antimicrobial therapy in patients with BSI.
Composition and Diversity of Gut Bacterial Community in Different Life Stages of Osmia excavata Alfken (Hymenoptera: Megachilidae)
Authors: Wang Guangzhao , Wang Guiping , Ma Yixiang , Lv Zhaoyun , You Yinwei , Ma Pengtao , Yu Yi
Published: August 2024

Osmia excavata is an excellent pollinator in nature and plays a vital role in the conservation of agro-ecosystems and food security. Given the important role of the gut bacterial community in host health and regulation of host growth and development, using 16S rRNA gene sequencing data, the present study explored the composition of the gut bacterial community and its diversity at different life stages (eggs, young larvae, old larvae, young pupae, old pupae, and 1-day-old adults in cocoons) of the solitary bee Osmia excavata. The results showed that the core phyla in the gut of O. excavata at different life stages were Proteobacteria, Firmicutes, Bacteroidota, and Actinobacteriota, and the core genera were Sodalis, Tyzzerella, and Ralstonia. The highest intestinal bacterial diversity was found in the Egg period, and the lowest bacterial alpha diversity was found in the 1-day-old Adult period; the bacterial diversity of O. excavata showed a process of decreasing, as it was growing from the Egg period to the 1-day-old Adult period. Our study found that O. excavata undergoes a significant change in the structure of the gut flora when it grows from the young pupae to old pupae stage, a period of growth that coincides with the process of cocooning and isolation from the external environment after food depletion. This suggests that food and environmental factors are key contributors to the structure of the bacterial community in the gut of solitary bees.
Location Prediction Study of Fluorite Ore in Shallow Cover Area: Evidence from Integrated Geophysical Surveys
Authors: Cheng Liu , Han Li , Kai Yang , Yongbao Gao , Weidong Tang , Chuan Yao
Published: August 2024

The Beishan region is a vital fluorite metallogenic belt in northwest China, characterized by favorable geological conditions for fluorite mineralization. However, being located in the Gobi Desert and affected by shallow cover layers, only a few outcrops can be observed on the surface. Therefore, comprehensive geophysical research is necessary to locate and predict regional metallogenic potential and the spatial distribution of veins beneath the cover. This study conducted a combination of ground magnetic method (GM), induced polarization (IP) surveys, portable gamma-ray (PGR), portable X-ray fluorescence analyses (PXRF), and audio Magnetotelluric (AMT) to conduct comprehensive exploration. The IP and GM effectively identified concealed ore-bearing space distributions and ground PGR- and PXRF-constrained mineralization anomalies, while AMT surveys constructed deep electrical structure models for ore deposits. This approach delineated concealed fluorite deposit locations as well as potential magmatic–hydrothermal migration pathways. Engineering verification confirmed the effectiveness of this method combination. This study established a comprehensive geological–geophysical positioning prediction technique that can serve as a reference for locating and predicting fluorite deposits in shallow-covered areas within the Gobi Desert.
Cross-Linked Starch as Media for Crystal Violet Elimination from Water: Modeling Batch Adsorption with Fuzzy Regression
Authors: Bahrami Mehdi , Amiri Mohammad Javad , Busquets Rosa , Nematollahi Mohammad Javad
Published: August 2024

A scalable and cost-effective solution for removing pollutants from water is to use biodegradable and eco-friendly sorbents that are readily available such as starch. The current research explored the removal of crystal violet (CV) dye from water using chemically modified potato starch. The adsorbent was prepared by cross-linking potato starch with sodium trimetaphosphate (STMP). The impact of various operating factors including pH, temperature, contact time, initial CV concentration, and adsorbent dosage on the removal of CV were investigated using batch experiments. The adsorption data were analyzed using a fuzzy regression approach, which provided a range-based representation of the model’s output. The cross-linked starch adsorbent was mesoporous, with a mean pore diameter of 9.8 nm and a specific surface area of 2.7 m2/g. The adsorption of CV by the STMP cross-linked potato starch was primarily influenced by the adsorbent dosage, followed by the solution pH, temperature, initial CV concentration, and contact time. The fuzzy regression model accurately predicted the independent experimental data of CV removal with an R2 of 0.985, demonstrating its value as a tool for the continuous monitoring of CV removal as well as optimizing water treatment conditions.
Green Synthesis of Silver Nanoparticles Using Cashew Nutshell Liquid (CNSL): Characterization and Methylene Blue Removal Studies
Authors: Carollo Justyn , Ballesteros-Plata Daniel , Rodríguez-Aguado Elena , Bashkova Svetlana
Published: August 2024

In this work, silver nanoparticles (AgNPs) were synthesized from cashew nutshell liquid (CNSL) by varying the concentration of silver ions and the pH of the CNSL extract. The synthesized AgNPs were further characterized to study their surface, structural, and morphological properties and tested for the removal of methylene blue (MB) dye. The results of this study showed that depending on the conditions, particles of various sizes, ranging from 1 to 60 nm, and different degrees of stabilization and agglomeration were produced. The concentration of silver ions equal to 3 mM and the pH of the extract of ~4.5 (AgNP3) resulted in the most efficient synthesis, where particles appeared to be highly stabilized and homogeneously distributed on the surface, exhibiting a small average particle size and a narrow particle size distribution (6.7 ± 6.5 nm). Such particles further showed the highest percent removal of MB, where up to 80% removal was recorded within the first 20 min. Higher concentrations of silver ions and higher pH of the extract resulted in substantial particle agglomeration and particles being over-capped by the CNSL biomolecules, respectively, which further negatively affected the ability of particles to remove MB. Finally, the fact that visible light showed no significant effect on the removal of MB, with the average removal rates found to be about the same as in the dark, suggests the strong catalytic nature of AgNPs, which facilitates the electron transfer reactions leading to MB reduction.
Surface Modification of Calcined Kaolinite for Enhanced Solvent Dispersion and Mechanical Properties in Polybutylene Adipate/Terephthalate Composites
Authors: Yuan Yongbing , Tang Xinyu , Sun Honghong , Shi Junkang , Zhou Congshan , Northwood Derek O , Waters Kristian E , Ma Hao
Published: August 2024

In order to regulate the surface properties of calcined kaolinite for the purpose of achieving uniform distribution within various polar dispersion media, 3-aminopropyltriethoxysilane and phenyl glycidyl ether were employed to chemically modify calcined kaolinite. The grafting rate, surface properties, and dispersion properties of calcined kaolinite particles in different polar organic media were changed by varying the dosage of the modifiers. FT-IR analysis confirmed successful surface modification, while thermogravimetric analysis indicated a maximum graft coverage of 18.44 μmol/m2 for the modified particles. Contact angle measurements and particle size distribution analyses demonstrated the effective adjustment of surface characteristics by the modifiers. Specifically, at a mass ratio of 1.0 of modifier to kaolinite particles, the modified particles exhibited a contact angle of around 125°, achieving uniform dispersion in different polarity media. Particle size distribution ranged from 1600 nm to 2100 nm in cyclohexane and petroleum ether, and from 900 nm to 1200 nm in dioxane, ethyl acetate, and DMF, showcasing a significant improvement in dispersion performance compared to unmodified particles. Concurrently, to improve the mechanical properties of PBAT, modified particles were incorporated into the PBAT matrix, and the effect of modified particle addition on the tensile strength and fracture tensile rate of the composites was investigated. The optimal amount of modified particles is 6 wt.%~8 wt.%. This article aims at synthesizing modifier molecules containing different hydrophilic and hydrophobic groups to chemically graft onto the surface of calcined kaolinite. The hydrophilic and hydrophobic groups on the modified particles can adapt to dispersed systems of different polarities and achieve good distribution within them. The modified particles are added to PBAT to achieve good compatibility and enhance the mechanical properties of the composite material.
Photoinitiators for Medical Applications—The Latest Advances
Authors: Dzwonkowska-Zarzycka Monika , Sionkowska Alina
Published: August 2024

Photopolymerization is becoming increasingly popular in industry due to its copious advantages. The vital factor in the entire pre-polymerization formulation is the presence of photoinitiators. Depending on the application, photoinitiators have different features. Hence, scientists are particularly interested in developing new photoinitiators that can expand the scope of applications and be used to create products with the features demanded by current trends. This brief review summarizes the photoinitiators used in dental materials and hydrogels and those obtained from natural and synthetic sources.
Clustering Molecules at a Large Scale: Integrating Spectral Geometry with Deep Learning
Authors: Akgüller Ömer , Balcı Mehmet Ali , Cioca Gabriela
Published: August 2024

This study conducts an in-depth analysis of clustering small molecules using spectral geometry and deep learning techniques. We applied a spectral geometric approach to convert molecular structures into triangulated meshes and used the Laplace–Beltrami operator to derive significant geometric features. By examining the eigenvectors of these operators, we captured the intrinsic geometric properties of the molecules, aiding their classification and clustering. The research utilized four deep learning methods: Deep Belief Network, Convolutional Autoencoder, Variational Autoencoder, and Adversarial Autoencoder, each paired with k-means clustering at different cluster sizes. Clustering quality was evaluated using the Calinski–Harabasz and Davies–Bouldin indices, Silhouette Score, and standard deviation. Nonparametric tests were used to assess the impact of topological descriptors on clustering outcomes. Our results show that the DBN + k-means combination is the most effective, particularly at lower cluster counts, demonstrating significant sensitivity to structural variations. This study highlights the potential of integrating spectral geometry with deep learning for precise and efficient molecular clustering.
Synthesis and Characterization of Copper(II) and Nickel(II) Complexes with 3-(Morpholin-4-yl)propane-2,3-dione 4-Allylthiosemicarbazone Exploring the Antibacterial, Antifungal and Antiradical Properties
Authors: Graur Ianina , Graur Vasilii , Cadin Marina , Garbuz Olga , Bourosh Pavlina , Melnic Elena , Lozan-Tirsu Carolina , Balan Greta , Tsapkov Victor , Fala Valeriu , Gulea Aurelian
Published: August 2024

The eleven new copper(II) and nickel(II) coordination compounds [Cu(L)Br]2 (1), [Cu(L)Cl] (2), [Cu(L)NO3] (3), [Ni(L)Cl] (4), [Ni(HL)2](NO3)2 (5), and [Cu(A)(L)]NO3, where A is 1,10-phenanthroline (6), 2,2′-bipyridine (7), 3,4-dimethylpyridine (8), 3-methylpyridine (9), pyridine (10) and imidazole (11) were synthesized with 3-(morpholin-4-yl)propane-2,3-dione 4-allylthiosemicarbazone (HL). The new thiosemicarbazone was characterized by NMR and FTIR spectroscopy. All the coordination compounds were characterized by elemental analysis and FTIR spectroscopy. Also, the crystal structures of HL and complexes 1, 6, 7, and 11 were determined using single-crystal X-ray diffraction analysis. Complex 1 has a dimeric molecular structure with two bromide bridging ligands, while 6, 7, and 11 are ionic compounds and comprise monomeric complex cations. The studied complexes manifest antibacterial and antifungal activities and also have an antiradical activity that, in many cases, surpasses the activity of trolox, which is used as a standard antioxidant in medicine. Copper complexes 1–3 have very weak antiradical properties (IC50 > 100 µM), but nickel complexes 4–5 are strong antiradicals with IC50 values lower than that of trolox. The mixed ligand copper complexes with additional ligand of N-heteroaromatic base are superior to complexes without these additional ligands. They are 1.4–5 times more active than trolox.
Recent Developments in Photoinduced Decarboxylative Acylation of α-Keto Acids
Authors: Lu Shuaiqi , Xiang Yilong , Chen Jingfu , Shu Chao
Published: August 2024

Ketones are ubiquitous patterns found in various biological molecules and natural products. In recent years, a number of acylation methods have been developed based on the use of α-oxocarboxylic acids as acyl-transfer reagents, with particular emphasis on the photoinduced decarboxylative acylation of α-keto acids. This review focuses on the latest advancements in acylation methodologies through the decarboxylation of α-keto acids over the past several years, highlighting their product diversity, selectivity, and applicability. Where possible, the mechanistic rationale is presented, providing a positive outlook for the promising future of this field.
Fluorescence Turn-Off Ligand for Parallel G-Quadruplexes
Authors: Nowak-Karnowska Joanna , Głuszyńska Agata , Kosman Joanna , Dembska Anna
Published: August 2024

Parallel-stranded G-quadruplex structures are found to be common in the human promoter sequences. We tested highly fluorescent 9-methoxyluminarine ligand (9-MeLM) binding interactions with different parallel G-quadruplexes DNA by spectroscopic methods such as fluorescence and circular dichroism (CD) titration as well as UV melting profiles. The results showed that the studied 9-MeLM ligand interacted with the intramolecular parallel G-quadruplexes (G4s) with similar affinity. The binding constants of 9-methoxyluminarine with different parallel G4s were determined. The studies upon oligonucleotides with different flanking sequences on c-MYC G-quadruplex suggest that 9-methoxyluminarine may preferentially interact with 3′end of the c-MYC promoter. The high decrease in 9-MeLM ligand fluorescence upon binding to all tested G4s indicates that 9-methoxyluminarine molecule can be used as a selective fluorescence turn-off probe for parallel G-quadruplexes.
Ionic Liquid Catalysis in Cyclic Carbonate Synthesis for the Development of Soybean Oil-Based Non-Isocyanate Polyurethane Foams
Authors: Kiełkiewicz Damian , Siewniak Agnieszka , Gaida Rafał , Greif Małgorzata , Chrobok Anna
Published: August 2024

A method for obtaining non-isocyanate polyurethane (NIPU) foams from cyclic carbonate (CC) based on soybean oil was developed. For this purpose, cyclic carbonate was synthesized from epoxidized soybean oil and CO2 using various ionic liquids (ILs) as catalysts. Among the tested ILs, the highest selectivity (100%) and CC yield (98%) were achieved for 1-ethyl-3-methylimidazolium ([emim]Br). Without any purification, the resulting cyclic carbonate was reacted directly with diethylenetriamine as a model crosslinking agent to produce NIPU foams. It was found that the soybean oil-based CC synthesized with bromide imidazolium ionic liquids exhibited significantly shorter gelling times (8 min 50 s for [emim]Br and 9 min 35 s for [bmim]Br) compared to those obtained with the conventional TBAB catalyst (26 min 15 s). A shorter gelling time is a crucial parameter for the crosslinking process in foams. The obtained foams were subjected to mechanical tests and a morphology analysis.
The Synthesis of SNAC Phenolate Salts and the Effect on Oral Bioavailability of Semaglutide
Authors: Shapira-Furman Tovi , Bar-Hai Ayala , Hoffman Amnon , Domb Abraham J.
Published: August 2024

Purpose: Sodium N-[8-(2-hydroxybenzoyl)amino]caprylate (SNAC) is a well-known penetration enhancer widely used in commercial applications. This study aims to broaden its properties through a novel strategy of converting it into its phenolate salts. The objective is to investigate the synthesis of SNAC phenolate salts, specifically SNAC–choline (SNAC-CH), SNAC–sodium (SNAC-Na), and SNAC–phosphatidylcholine (SNAC-PC), and to explore their potential application in improving the oral absorption of semaglutide. Methods: The synthesis of SNAC phenolate salts was confirmed through 1H-NMR, FTIR, and an elemental analysis of C, H, N, and O. In vivo testing was conducted to assess the oral delivery of semaglutide using these synthesized SNAC phenolate salts. Pharmacokinetic (PK) values were measured to evaluate the impact on drug absorption. Results: The synthesis of SNAC phenolate salts (SNAC-CH, SNAC-Na, and SNAC-PC) was successfully achieved under appropriate conditions, and their structures were confirmed using analytical techniques such as IR, NMR, and CHN elemental analysis. The paradigm of their use was evaluated through an oral pharmacokinetic (PK) in vivo study using SNAC phenolate salts, which did not impair the original SNAC PK values. This suggests that this strategy holds promise as a potential new effective enhancer for oral absorption. Conclusions: The utilization of SNAC phenolate salts presents a novel and promising strategy for extending the verity of penetration enhancers’ molecules and properties. Synthesizing phenolate salts represents a new chemical strategy that may open new avenues in molecular development. This approach holds future potential to enhance the oral delivery of peptide drugs like semaglutide without compromising therapeutic efficacy. Overall, it offers significant advancements in the field by providing a potential alternative to injectable peptides through oral delivery systems.
Investigating the Electrochemical Performance of MnFe2O4@xC Nanocomposites as Anode Materials for Sodium-Ion Batteries
Authors: Liu Shi-Wei , Niu Bai-Tong , Lin Bi-Li , Lin Yuan-Ting , Chen Xiao-Ping , Guo Hong-Xu , Chen Yan-Xin , Lin Xiu-Mei
Published: August 2024

Transition metal oxides (TMOs) are important anode materials in sodium-ion batteries (SIBs) due to their high theoretical capacities, abundant resources, and cost-effectiveness. However, issues such as the low conductivity and large volume variation of TMO bulk materials during the cycling process result in poor electrochemical performance. Nanosizing and compositing with carbon materials are two effective strategies to overcome these issues. In this study, spherical MnFe2O4@xC nanocomposites composed of MnFe2O4 inner cores and tunable carbon shell thicknesses were successfully prepared and utilized as anode materials for SIBs. It was found that the property of the carbon shell plays a crucial role in tuning the electrochemical performance of MnFe2O4@xC nanocomposites and an appropriate carbon shell thickness (content) leads to the optimal battery performance. Thus, compared to MnFe2O4@1C and MnFe2O4@8C, MnFe2O4@4C nanocomposite exhibits optimal electrochemical performance by releasing a reversible specific capacity of around 308 mAh·g−1 at 0.1 A·g−1 with 93% capacity retention after 100 cycles, 250 mAh·g−1 at 1.0 A g−1 with 73% capacity retention after 300 cycles in a half cell, and around 111 mAh·g−1 at 1.0 C when coupled with a Na3V2(PO4)3 (NVP) cathode in a full SIB cell.