bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study and GRNN Modeling of Shrinkage Characteristics for Wax Patterns of Gas Turbine Blades Considering the Influence of Complex Structures
Authors: Liu Changhui , Jiang Chenghong , Zhou Zhenfeng , Li Fei , Wang Donghong , Shuai Sansan
Published: June 2023

With the continuous increase in power demand in aerospace, shipping, electricity, and other industries, a series of manufacturing requirements such as high precision, complex structure, and thin wall have been put forward for gas turbines. Gas turbine blades are the key parts of the gas turbine. Their manufacturing accuracy directly affects the fuel economy of the gas turbine. Thus, how to improve the manufacturing accuracy of gas turbine blades has always been a hot research topic. In this study, we perform a quantitative study on the correlation between process parameters and the overall wax pattern shrinkage of gas turbine blades in the wax injection process. A prediction model based on a generalized regression neural network (GRNN) is developed with the newly defined cross-sectional features consisting of area, area ratio, and some discrete point deviations. In the qualitative analysis of the cross-sectional features, it is concluded that the highest accuracy of the wax pattern is obtained for the fourth group of experiments, which corresponds to a holding pressure of 18 bars, a holding time of 180 s, and an injection temperature of 62 °C. The prediction model is trained and tested based on small experimental data, resulting in an average RE of 1.5% for the area, an average RE of 0.58% for the area ratio, and a maximum MSE of less than 0.06  mm2 for discrete point deviations. Experiments show that the GRNN prediction model constructed in this study is relatively accurate, which means that the shrinkage of the remaining major investment casting procedures can also be modeled and controlled separately to obtain turbine blades with higher accuracy.
Gearbox Fault Diagnosis Based on Refined Time-Shift Multiscale Reverse Dispersion Entropy and Optimised Support Vector Machine
Authors: Wang Xiang , Jiang Han
Published: June 2023

The fault diagnosis of a gearbox is crucial to ensure its safe operation. Entropy has become a common tool for measuring the complexity of time series. However, entropy bias may occur when the data are not long enough or the scale becomes larger. This paper proposes a gearbox fault diagnosis method based on Refined Time-Shifted Multiscale Reverse Dispersion Entropy (RTSMRDE), t-distributed Stochastic Neighbour Embedding (t-SNE), and the Sparrow Search Algorithm Support Vector Machine (SSA-SVM). First, the proposed RTSMRDE was used to calculate the multiscale fault features. By incorporating the refined time-shift method into Multiscale Reverse Dispersion Entropy (MRDE), errors that arose during the processing of complex time series could be effectively reduced. Second, the t-SNE algorithm was utilized to extract sensitive features from the multiscale, high-dimensional fault features. Finally, the low-dimensional feature matrix was input into SSA-SVM for fault diagnosis. Two gearbox experiments showed that the diagnostic model proposed in this paper had an accuracy rate of 100%, and the proposed model performed better than other methods in terms of diagnostic performance.
The Neutral Voltage Difference Signal as a Means of Investigating Eccentricity and Demagnetization Faults in an AFPM Synchronous Generator
Authors: Barmpatza Alexandra C.
Published: June 2023

This article investigates the neutral voltage difference signal, VNO signal, for fault diagnosis. The aforementioned signal is the signal of the voltage between the common star point of the stator and the common star point of the load. The under-study faults are demagnetization and static eccentricity faults, while the machine in which the faults are investigated is an axial flux permanent magnet (AFPM) synchronous generator, suitable for wind power applications. This study was conducted using a 3D finite element method (3D-FEM), and the machine’s FEM model was validated through experiments. This method is one of the most accurate methods for electrical machine computation, allowing for a detailed study of electromagnetic behavior. The components that constitute the VNO signal were determined using a 3D-FEM software program (Opera 18R2). Subsequently, further analysis was performed using MATLAB R2022b software, and a fast Fourier transform (FFT) was applied to this signal. In all the investigated faulty cases, new harmonics appeared, and the healthy amplitudes of most of the already existing harmonics increased. These findings can be used for fault identification. The analysis revealed that the harmonic frequency of 1.5fs was the most dominant in the case of demagnetization, while in the case of static eccentricity, the most dominant harmonic was a frequency equal to the machine’s operating frequency, fs. The novelty of this study is that this signal has not previously been used for fault identification, especially in AFPM synchronous machines. This signal depends on EMF voltage and stator phase currents but is less sinusoidal. Consequently, it can detect faults in cases where the aforementioned signals cannot be used for detection.
Attitude-Oriented Stability Control with Adaptive Impedance Control for a Wheeled Robotic System on Rough Terrain
Authors: Xu Kang , Li Jianyong , Si Jinge , Liu Yueming , Nie Meng
Published: June 2023

Base stability for a wheeled robot while driving over rough terrain is a challenging issue. This paper proposes a novel base-stability control framework, consisting of an AVIC (adaptive variable-impedance control), AVIC-based tracking controller, and a THV (terrain height variation) and AC (attitude control) AC-based controller to stabilize the base on rough terrain. The AVIC-based controller aims to track the desired trajectory of the robot base while suppressing lumped disturbance, including system uncertainties in the internal dynamics and unknown external disturbance. The THV-based controller is utilized as a feedforward controller to improve posture tracking performance in order to achieve a horizontal posture. The AC-based controller is employed to maintain the horizontal posture of the base. The effectiveness and robustness of the proposed controllers are validated by a series of numerical trials, and the results are evaluated.
Estimating the Critical Velocity of the Incipient Motion of Particles on the Cuttings Bed Surface: An Experimental and Theoretical Analysis
Authors: Shen Kaixiang , Xu Zhenqiang , Ju Guoshuai , Wang Yingsheng , Li Zijian
Published: June 2023

During the drilling of highly deviated and horizontal wells, a pump shutdown causes drill cuttings to settle and form a cuttings bed in the annulus. This study investigated the incipient motion law of the particles on the cuttings bed surface when the drilling fluid starts circulating again. This work could help field engineers to determine a reasonable incipient pump displacement to improve hole-cleaning efficiency. In this study, the effects of the well inclination angle, cuttings size, and different cuttings densities on the critical velocity of particle motion are analyzed experimentally, using a large-scale flow loop. Next, based on a stress analysis of the particles on the cutting bed surface and on the boundary layer flow around the particles, an analytical formula for the surface shear force of the drilling fluid on particles is derived and a critical velocity model for incipient motion is established. Verification is then carried out and combined with the experimental results. This study has important implications for the design of drilling operations and for the management of cuttings transport in oil and gas wells. It can guide the setting and prediction of pump discharge to improve hole-cleaning efficiency.
Software Defect Prediction Using Dagging Meta-Learner-Based Classifiers
Authors: Babatunde Akinbowale , Ogundokun Roseline , Adeoye Latifat , Misra Sanjay
Published: June 2023

To guarantee that software does not fail, software quality assurance (SQA) teams play a critical part in the software development procedure. As a result, prioritizing SQA activities is a crucial stage in SQA. Software defect prediction (SDP) is a procedure for recognizing high-risk software components and determining the influence of software measurements on the likelihood of software modules failure. There is a continuous need for sophisticated and better SDP models. Therefore, this study proposed the use of dagging-based and baseline classifiers to predict software defects. The efficacy of the dagging-based SDP model for forecasting software defects was examined in this study. The models employed were naïve Bayes (NB), decision tree (DT), and k-nearest neighbor (kNN), and these models were used on nine NASA datasets. Findings from the experimental results indicated the superiority of SDP models based on dagging meta-learner. Dagging-based models significantly outperformed experimented baseline classifiers built on accuracy, the area under the curve (AUC), F-measure, and precision-recall curve (PRC) values. Specifically, dagging-based NB, DT, and kNN models had +6.62%, +3.26%, and +4.14% increments in average accuracy value over baseline NB, DT, and kNN models. Therefore, it can be concluded that the dagging meta-learner can advance the recognition performances of SDP methods and should be considered for SDP processes.
Approximate Subdifferential of the Difference of Two Vector Convex Mappings
Authors: Ammar Abdelghali , Laghdir Mohamed , Ed-dahdah Ahmed , Hanine Mohamed
Published: June 2023

This paper deals with the strong approximate subdifferential formula for the difference of two vector convex mappings in terms of the star difference. This formula is obtained via a scalarization process by using the approximate subdifferential of the difference of two real convex functions established by Martinez-Legaz and Seeger, and the concept of regular subdifferentiability. This formula allows us to establish approximate optimality conditions characterizing the approximate strong efficient solution for a general DC problem and for a multiobjective fractional programming problem.
Bilevel Optimal Sizing and Operation Method of Fuel Cell/Battery Hybrid All-Electric Shipboard Microgrid
Authors: Jin Hao , Yang Xinhang
Published: June 2023

The combination of transportation electrification and clean energy in the shipping industry has been a hot topic, and related applications of hybrid all-electric ships (AESs) have emerged recently. However, it has been found that ship efficiency will be negatively impacted by improper component size and operation strategy. Therefore, the bilevel optimal sizing and operation method for the fuel cell/battery hybrid AES is proposed in this paper. This method optimizes the sizing of the AES while considering joint optimal energy management and voyage scheduling. The sizing problem is formulated at the upper level, and the joint scheduling problem is described at the lower level. Then, multiple cases are simulated to verify the effectiveness of the proposed method on a passenger ferry, and the results show that a 5.3% fuel saving and 5.2% total cost reduction can be achieved. Correspondingly, the ship’s energy efficiency is improved. This approach also can be used in similar vessels to enhance their overall performance and sustainability.
A Look at Generalized Degenerate Bernoulli and Euler Matrices
Authors: Hernández Juan , Peralta Dionisio , Quintana Yamilet
Published: June 2023

In this paper, we consider the generalized degenerate Bernoulli/Euler polynomial matrices and study some algebraic properties for them. In particular, we focus our attention on some matrix-inversion formulae involving these matrices. Furthermore, we provide analytic properties for the so-called generalized degenerate Pascal matrix of the first kind, and some factorizations for the generalized degenerate Euler polynomial matrix.
Impact of Age on Long-Term Urinary Continence after Robotic-Assisted Radical Prostatectomy
Authors: Cano Garcia Cristina , Wenzel Mike , Humke Clara , Wittler Clarissa , Dislich Julius , Incesu Reha-Baris , Köllermann Jens , Steuber Thomas , Graefen Markus , Tilki Derya , Karakiewicz Pierre I. , Kluth Luis A. , Preisser Felix , Chun Felix K. H. , Mandel Philipp , Hoeh Benedikt
Published: June 2023

Aim and Objectives: We aimed to test the impact of age on long-term urinary continence (≥12 months) in patients undergoing robotic-assisted radical prostatectomy. Methods and Materials: We relied on an institutional tertiary-care database to identify the patients who underwent robotic-assisted radical prostatectomy between January 2014 and January 2021. Patients were divided into three age groups: age group one (≤60 years), age group two (61–69 years) and age group three (≥70 years). Multivariable logistic regression models tested the differences between the age groups in the analyses addressing long-term urinary continence after robotic-assisted radical prostatectomy. Results: Of the 201 prostate cancer patients treated with robotic-assisted radical prostatectomy, 49 (24%) were assigned to age group one (≤60 years), 93 (46%) to age group two (61–69 years) and 59 (29%) to age group three (≥70 years). The three age groups differed according to long-term urinary continence: 90% vs. 84% vs. 69% for, respectively, age group one vs. two vs. three (p = 0.018). In the multivariable logistic regression, age group one (Odds Ratio (OR) 4.73, 95% CI 1.44–18.65, p = 0.015) and 2 (OR 2.94; 95% CI 1.23–7.29; p = 0.017) were independent predictors for urinary continence, compared to age group three. Conclusion: Younger age, especially ≤60 years, was associated with better urinary continence after robotic-assisted radical prostatectomy. This observation is important at the point of patient education and should be discussed in informed consent.
High AST/ALT Ratio Is Associated with Cardiac Involvement in Acute COVID-19 Patients
Authors: Karatas Mesut , Keles Nursen , Parsova Kemal Emrecan , Ciftci Hatice Ozge , Ozkok Sercin , Kahraman Erkan , Durak Furkan , Kocogullari Cevdet Ugur , Yiyit Nurettin
Published: June 2023

Background and Objectives: We aimed to assess the effect of AST/ALT ratio on echocardiographic and cardiac magnetic resonance imaging (CMRI) parameters after COVID-19 patients recover. Materials and Methods: 87 patients with COVID-19 were included in the study. The patients were hospitalized with COVID-19 pneumonia, but the patients did not need intensive care unit follow-up or non-invasive mechanical ventilation support. After a discharge and two weeks following the positive swab test result, patients were considered eligible if they had any symptoms. Transthoracic echocardiography (TTE) was performed within 24 h prior to CMRI. The median value of AST/ALT ratio was found, and the study population was divided into two subgroups based on the median AST/ALT ratio value. The clinical features, blood test, TTE and CMRI results were compared between subgroups. Results: C-reactive protein, D-dimer and fibrinogen were found to be significantly higher in patients with high AST/ALT ratio. LVEF, TAPSE, S’, and FAC were significantly lower in patients with high AST/ALT ratio. LV-GLS were significantly lower in patients with high AST/ALT ratio. In CMRI, native T1 mapping signal, native T2 mapping signal and extracellular volume raised significantly in patients with high AST/ALT ratio. Right ventricle stroke volume and right ventricle ejection fraction were significantly lower in patients with high AST/ALT ratio, but right ventricle end systolic volume was significantly higher in patients with high AST/ALT ratio. Conclusion: High AST/ALT ratio is related to impaired right ventricular function parameters with CMRI and echocardiography after recovery from acute COVID-19. Assessment of AST/ALT ratio at hospital admission may be used to assess the risk of cardiac involvement in COVID-19 disease, and these patients may require closer follow-up during and after the course of COVID-19.
Epidemiology, Risk Factors, and Prevention of Head and Neck Squamous Cell Carcinoma
Authors: Barsouk Adam , Aluru John Sukumar , Rawla Prashanth , Saginala Kalyan , Barsouk Alexander
Published: June 2023

Head and neck squamous cell carcinoma (HNSCC) is a group of malignancies, involving the oral cavity, pharynx, hypopharynx, larynx, nasal cavity, and salivary glands, that together compose the seventh most common cancer diagnosis worldwide. With 890,000 new cases and 450,000 deaths annually per GLOBOCAN estimates, HNSCC accounts for roughly 4.5% of cancer diagnoses and deaths. In the developing world, the incidence of HNSCC is growing with increasing consumption of tobacco (smoked or chewed), alcohol, and areca nut (betel quid). Alcohol and tobacco have a synergistic effect, with the heavy consumption of both increasing HNSCC risk 40-fold. In developed nations, HPV-related HNSCC surpasses tobacco- and alcohol-related disease. HPV-related HNSCC more commonly affects the oropharynx, hypopharynx, and larynx than the oral cavity, and is associated with a significantly longer median survival (130 months vs. 20 months). Discrepancies in etiology as well as disparities in lifestyle choices and access to healthcare may account for the greater incidence and poorer survival of HNSCC among minority and lower-socioeconomic-status communities in developed nations. Pharmacotherapy and counseling together have been shown to be effective in promoting smoking and alcohol cessation. Education on cancer risk and community engagement have reduced areca nut consumption in Asia as well as in diaspora communities. HPV vaccination, starting at age 11–12 for both sexes, has been shown to reduce the prevalence of high-risk HPV serologies and prevent pre-cancerous lesions of the cervix, vagina, and vulva. As of 2020, 58.6% of eligible adolescents in the US have received the full two-vaccine series. Increased adoption of vaccination, education on safe sex practices, and routine visual oral screening for high-risk patients would curb growing HNSCC incidence in developed nations.
The Effect of Forging and Heat Treatment Variables on Microstructure and Mechanical Properties of a Re-Bearing Powder-Metallurgy Nickel Base Superalloy
Authors: Mukhtarov Shamil , Karyagin Dmitry , Ganeev Artem , Zainullin Rishat , Shakhov Ruslan , Imayev Valery
Published: June 2023

In our previous works, the effects of forging and heat treatment variables on microstructure evolution and mechanical properties have been studied for an ingot-metallurgy Re-bearing nickel base superalloy. To overcome the issues associated with the production of large-scale ingots and fine-grained workpieces, in the present work, the effect of hot forging and heat treatment variables was studied in a Re-bearing nickel base superalloy prepared via powder metallurgy. The purpose of the study was to reach the properly balanced mechanical properties for the potential use of the superalloy as a disc material. The initial as-HIPed workpieces were subjected to different hot forging and post-forging heat treatment or only to heat treatment (no forging). For the processed workpieces, the recrystallization behavior, size, morphology and volume fraction of γ′ precipitates were evaluated by scanning electron microscopy followed by a study of mechanical properties. The most properly balanced mechanical properties (strength, ductility, creep resistance and creep rupture lifetime) were reached for the γ grain size of dγ ≈ 13.6 µm. A finer and coarser γ grain size (down to dγ ≈ 2.6 and up to dγ ≈ 37.5 µm) even when superimposed with a higher volume fraction of dispersed secondary γ′ precipitates (in the case of dγ = 27–37.5 µm) was associated with worse mechanical properties.
Effects of Ammonium Salts on Rare Earth Leaching Process of Weathered Crust Elution-Deposited Rare Earth Ores
Authors: Zhang Zhenyue , Zhou Changyu , Chen Wendou , Long Fei , Chen Zhuo , Chi Ru’an
Published: June 2023

In order to reveal the influence of ammonium salts on the rare earth leaching process of weathered crust elution-deposited rare earth ores, ammonium acetate, ammonium chloride, and ammonium sulfate were used as leaching agents. The effects of the leaching agent on the rare earth leaching efficiency and the expansion, dissolution, and transformation behavior of clay minerals in the rare earth leaching process were studied. The results showed that rare earth leaching efficiency followed the order ammonium acetate > ammonium chloride > ammonium sulfate, with values of 90.60%, 85.96%, and 84.12%, respectively. The swelling ratio of clay mineral followed the order ammonium acetate < ammonium chloride < ammonium sulfate; the clay mineral swelling ratio was 2.09% when ammonium acetate was the leaching agent. Thermogravimetric analysis showed that the interlayer water content was the lowest when ammonium acetate was used as the leaching agent. Under the conditions of different leaching agents, the clay mineral contents changed from illite and halloysite to smectite and kaolinite. When ammonium acetate was used as the leaching agent, the relative conversion of illite was 1.49%, and that of smectite was only 0.17%. SEM analysis showed that the clay minerals expanded and dissolved obviously when ammonium chloride and ammonium sulfate were used as the leaching agents. Meanwhile, the clay mineral layered structure was relatively complete when ammonium acetate was used as the leaching agent. Therefore, when ammonium acetate was used as the leaching agent, it had the least effect on the swelling, dissolution, and transformation of clay minerals. This can provide a theoretical basis for the safe production of weathered crust elution-deposited rare earth ore, and for the screening of green and efficient leaching agents.
Confirming Debonding of Non-Metallic Inclusions as an Important Factor in Damage Initiation in Bearing Steel
Authors: Nikolic Ksenija , De Wispelaere Jelle , Ravi Gopalakrishnan , Hertelé Stijn , Depover Tom , Verbeken Kim , Petrov Roumen H.
Published: June 2023

Damage in bearings is closely associated with the presence of microstructural alterations, known as white etching areas (WEAs) and white etching cracks (WECs). One of the main reasons for the creation of these microstructural alterations is the presence of defects in the material, such as non-metallic inclusions. Manganese sulfides and aluminum oxides are widely reported in the literature as the most common types of non-metallic inclusions found in bearing steels. This study classifies 280 non-metallic inclusions in an investigated bearing steel according to several criteria: bonded/debonded with the matrix, size, shape, orientation angle, depth below the raceway surface, and chemical composition. Contrary to the findings in the literature, this investigation reports that the chemical composition of the inclusion (MnS + Al2O3) is of secondary importance when considering factors for damage initiation. The orientation of the microstructural alterations is observed to coincide with the high-stress regions, indicating a relation between the formation of butterfly wings and the white etching crack. In our investigation, butterfly wings typically exhibit a 45-degree pattern originating from the non-metallic inclusions. Conversely, the white etching crack starts from the non-metallic inclusion at a shallower angle in correspondence to the raceway. This can be attributed to the stress state, which corresponds to a region where extensive white etching cracks are formed. In conclusion, the microstructural observations demonstrate that the state of non-metallic inclusion—i.e., whether they are bonded or not to the steel matrix—plays an essential role in initiating rolling contact fatigue damage.
Investigation on the Dynamic Behaviors of Aluminum Foam Sandwich Beams Subjected to Repeated Low-Velocity Impacts
Authors: Guo Kailing , Mu Mengying , Zhou Shuo
Published: June 2023

Marine structures are frequently subjected to repeated-impact loadings during navigation and operation. The structural damage accumulates, resulting in structural failures and even serious accidents. Experiments were performed using an INSTRON drop tower to investigate the dynamic behaviors of aluminum foam sandwich beams (AFSBs) subjected to repeated impacts; moreover, the mechanism of plastic deformation and damage and the energy absorption characteristics were analyzed. The results showed that as the number of impacts increased, the AFSB experienced progressive failure. The peak impact force, the deflection of the face sheets, and the rebound velocity gradually increased with increasing numbers of impacts, while their increments declined. However, when cracks occurred on the aluminum foam core and face sheets, as the number of impacts increased, the peak force and the rebound velocity decreased, while the amount of deflection in the front and back faces progressively increased. Before the foam core cracked, as the number of impacts increased, the elastic energy increased, while the plastic energy decreased. Once the foam core cracked, the plastic energy increased suddenly. During repeated impacts, the energy absorbed via local indentation in each impact initially increased with the number of impacts, and then decreased before finally becoming constant.
Optimization of a Certain Type of Aero-Engine Three-Tooth Mortise and Tenon Joint Structure against Fretting Fatigue
Authors: Qian Zhengming , Mi Dong , Cheng Benlin , Deng Lijun , Li Shaomeng , Zhang Hongjian , Cui Haitao
Published: June 2023

In turbine tenon joint structures, fretting fatigue is common and can have detrimental effects on the components. To increase the fretting fatigue life, the design of tenon joint structures must be optimized. A parametric model of the three-tooth mortise and tenon joint structure is developed in this research. Sensitivity analysis yields the primary characteristic parameters, which are then employed as design variables. The objective function is the life of fretting fatigue. An aero-engine turbine three-tooth mortise and tenon joint structure was optimized against fretting fatigue using a Multi-Island Genetic Algorithm (MIGA), which was then experimentally verified. The optimization was based on the multidisciplinary optimization platform ISIGHT to write batch files integrating ANSYS and MATLAB. According to the findings, the three-tooth mortise and tenon joint structure’s fretting fatigue life can be increased by 51.3% by applying the MIGA. The contact pressure was reduced by 0.54% and the maximum slip amplitude has been reduced by 13%. The approach of optimization’s efficacy was confirmed.
Effect of Residual Stress on Mode-I Stress Intensity Factor: A Quantitative Evaluation and a Suggestion of an Estimating Equation
Authors: Nguyen Thanh Tuan , Pham Van Son , Tran Hoang Anh , Nguyen Duc Huy , Nguyen Thu Huong , Dinh Hong Bo
Published: June 2023

An extensive literature review was conducted primarily to develop a comprehensive understanding of the quantitative behavior of residual stress (RS) distribution in weld joints. Based on prior data, various levels of the peak RS and distribution profiles were applied to a finite element analyses (FEA) model as an initial loading to evaluate the effect of RS on the Mode-I stress intensity factor (SIF), KI. The RS was not found to have a significant effect on the SIF values when the peak RS was less than 300 MPa. The enhanced effect of RS on the KI values was found to be more pronounced at a lower crack ratio, while the analytical form of the RS distribution had a minor effect. The effective boundary corrections function, FResidual, was derived under the effect of RS for 1T CT specimen for various crack geometries of the crack ratio, (a/W) of 0.2, 0.40, 0.50, 0.60, and 0.75, and with peak RS varying from 100 MPa to 600 MPa. The obtained effective function of KI can be employed to quantitatively evaluate the effect of RS on the fatigue performance of welded joints.
Maternal and Cord Blood Serum Metabolite Associations with Childhood Adiposity and Body Composition Outcomes
Authors: Bianco Monica E. , Vu My H. , Bain James R. , Muehlbauer Michael J. , Ilkayeva Olga R. , Scholtens Denise M. , Josefson Jami , Lowe William L.
Published: June 2023

Maternal metabolites influence the size of newborns independently of maternal body mass index (BMI) and glycemia, highlighting the importance of maternal metabolism on offspring outcomes. This study examined associations of maternal metabolites during pregnancy with childhood adiposity, and cord blood metabolites with childhood adiposity using phenotype and metabolomic data from the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study and the HAPO Follow-Up Study. The maternal metabolites analyses included 2324 mother–offspring pairs, while the cord blood metabolites analyses included 937 offspring. Multiple logistic and linear regression were used to examine associations between primary predictors, maternal or cord blood metabolites, and childhood adiposity outcomes. Multiple maternal fasting and 1 hr metabolites were significantly associated with childhood adiposity outcomes in Model 1 but were no longer significant after adjusting for maternal BMI and/or maternal glycemia. In the fully adjusted model, fasting lactose levels were negatively associated with child BMI z-scores and waist circumference, while fasting urea levels were positively associated with waist circumference. One-hour methionine was positively associated with fat-free mass. There were no significant associations between cord blood metabolites and childhood adiposity outcomes. Few metabolites were associated with childhood adiposity outcomes after adjusting for maternal BMI and glucose, suggesting that maternal BMI accounts for the association between maternal metabolites and childhood adiposity.
Modes of Action of 1,8-Cineol in Infections and Inflammation
Authors: Pries Ralph , Jeschke Stephanie , Leichtle Anke , Bruchhage Karl-Ludwig
Published: June 2023

The monoterpene 1,8-Cineol is a natural plant-based therapeutic agent that is commonly applied to treat different inflammatory diseases due to its mucolytic, anti-microbial and anti-inflammatory properties. It has become increasingly clear in the recent years that 1,8-Cineol spreads almost everywhere in the human body after its oral administration, from the gut to the blood to the brain. Its anti-microbial potential and even its anti-viral effects have been observed to include numerous bacteria and fungi species. Many recent studies help to better understand the cellular and molecular immunological consequences of 1,8-Cineol treatment in inflammatory diseases and further provide information concerning the mechanistic modes of action in the regulation of distinct inflammatory biosynthetic pathways. This review aims to present a holistic and understandable overview of the different aspects of 1,8-Cineol in infections and inflammation.
Correction: Maynard et al. Notes from the 2022 Folate, Vitamin B12, and One-Carbon Metabolism Conference. Metabolites 2023, 13, 486
Authors: Maynard Adam G. , Petrova Boryana , Kanarek Naama
Published: June 2023

Thanks to feedback from several speakers, text was amended, and citations updated, in the original article [...]
Subclinical Reactive Hypoglycemia with Low Glucose Effectiveness—Why We Cannot Stop Snacking despite Gaining Weight
Authors: Kishimoto Ichiro
Published: June 2023

Obesity has grown worldwide owing to modern obesogenic lifestyles, including frequent snacking. Recently, we studied continuous glucose monitoring in obese/overweight men without diabetes and found that half of them exhibit glucose levels less than 70 mg/dL after a 75-g oral glucose load without notable hypoglycemic symptoms. Interestingly, people with “subclinical reactive hypoglycemia (SRH)” snack more frequently than those without it. Since the ingestion of sugary snacks or drinks could further induce SRH, a vicious cycle of “Snacking begets snacking via SRH” can be formed. Glucose effectiveness (Sg) is an insulin-independent mechanism that contributes to most of the whole-body glucose disposal after an oral glucose load in people without diabetes. Our recent data suggest that both higher and lower Sg are associated with SRH, while the latter but not the former is linked to snacking habits, obesity, and dysglycemia. The present review addresses the possible role of SRH in snacking habits in people with obesity/overweight, taking Sg into account. It is concluded that, for those with low Sg, SRH can be regarded as a link between snacking and obesity. Prevention of SRH by raising Sg might be key to controlling snacking habits and body weight.
Impact of ASOS Real-Time Quality Control on Convective Gust Extremes in the USA
Authors: Cook Nicholas John
Published: June 2023

Most damage to buildings across the contiguous United States, in terms of number and total cost, is caused by gusts in convective events associated with thunderstorms. Their assessment relies on the integrity of meteorological observations. This study examines the impact on risk due to valid gust observations culled erroneously by the real-time quality control algorithm of the US Automated Surface Observation System (ASOS) after 2013. ASOS data before 2014 are used to simulate the effect of this algorithm at 450 well-exposed stations distributed across the contiguous USA. The peak gust is culled in around 10% of these events causing significant underestimates of extreme gusts. The full ASOS record, 2000–2021, is used to estimate and map the 50-year mean recurrence interval (MRI) gust speeds, the conventional metric for structural design. It is concluded that recovery of erroneously culled observations is not possible, so the only practical option to eliminate underestimation is to ensure that the 50-year MRI gust speed at any given station is not less than the mean for nearby surrounding stations. This also affects stations where values are legitimately lower than their neighbors, which represents the price that must be paid to eliminate unacceptable risk.
The Tobit-Unscented-Kalman-Filter-Based Attitude Estimation Algorithm Using the Star Sensor and Inertial Gyro Combination
Authors: Wang Xinmei , Zhang Hui , Gao Xiaodong , Zhao Rujin
Published: June 2023

For the orbit operation of spacecraft, due to environmental factors, a star sensor installed on the spacecraft must have data censoring, which greatly reduces the attitude determination ability of the traditional combined-attitude-determination algorithm. To address this problem, this paper proposes an algorithm for high-precision attitude estimation based on a Tobit unscented Kalman filter. This is on the basis of establishing the nonlinear state equation of the integrated star sensor and gyroscope navigation system. The measurement update process of the unscented Kalman filter is improved. The Tobit model is used to describe the gyroscope drift when the star sensor fails. The latent measurement values are calculated using the probability statistics, and the measurement error covariance expression is derived. The proposed design is verified via computer simulations. When the star sensor fails for 15 min, the accuracy of the Tobit unscented Kalman filter based on the Tobit model is improved by approximately 90% compared to the unscented Kalman filter. Based on the results, the proposed filter can effectively estimate the error caused by the gyro drift, and the method is effective and feasible, provided there is theoretical support for the engineering practice.
Potassium-Incorporated Titanium Oxide Nanoparticles Modulate Human Dendritic Cell Immune Response to Mycobacterium leprae
Authors: Warren Sam , Lee So Yoon , Barragan Jose , Kositangool Piya , Yoshikubo Hatsuko , Cervantes Jorge
Published: June 2023

The two polar clinical forms of leprosy, termed tuberculoid and lepromatous, have polarized cellular immune responses with complex immunological distinctions. The predominance of DCs in tuberculoid leprosy has been reported, while the lepromatous pattern of illness is associated with weak activation of local populations of DCs. TiO2 nanoparticles have previously been shown to induce maturation of these cells, leading to an inflammatory response similar to adjuvant usage in vaccine administration. We aimed to evaluate the effect of potassium-incorporated Ti oxide nanostructures, namely KTiOxs, in the response of human monocyte-derived DCs to live M. leprae. Human monocytic cell line dual THP-1, which harbors two inducible reporter plasmid systems for transcription factor activation of NF-κB and interferon regulating factor (IRF), was treated with titanium control or with 1 mol/L KOH-treated Ti or 10 mol/L KOH for 24 h. Subsequently, cells were infected with M. leprae. KTiOx nanoparticles increase DC phagocytic activity without inflammation. KTiOx exposure of DCs led to an increase in IRF activation with modulation of the inflammatory response to live M. leprae. It also led to differential secretion of the critical components of innate immune response and the development of cell-mediated immunity against intracellular pathogens. This study demonstrates the effect of nanostructures of KTiOxs and the usefulness of nanoparticle technology in the in vitro activation of human DCs against an infectious disease with a puzzling immune spectrum. Our findings may prompt future therapeutic strategies, such as DC immunotherapy for disseminated and progressive lepromatous lesions.
Cryptococcus gattii Can Use the Cactus Pilosocereus spp. to Grow and Develop a Capsule and Produce Melanin In Vitro
Authors: Ramos-Irizarry Paola , Sánchez Bárbara , Loperena-Álvarez Yaliz
Published: June 2023

Cryptococcus gattii is a pathogenic yeast, member of the C. neoformans/gattii complex. Previous work from our laboratory has established the presence of C. gattii on cacti lesions, providing proof that it can grow in a stressful environment. However, it is not known which part of the cactus the yeast uses for nutrients. The purpose of this research is to determine the ability of C. gattii to grow in different parts of the cactus to assess how the yeast adapts to grow in this unique environment. Cactus media were developed using the outer, inner, and whole cactus from Pilosocereus spp. Cryptcoccus gattii was grown on the different cactus media, along with potato dextrose agar as a control for 24 and 48 h at 30 °C. Compared to the control medium, yeast growth was reduced in all cactus media, while an increase in the capsule development of the yeast grown in the inner part and the whole-cactus media was observed. Interestingly, the yeast produces melanin when grown in the outer membrane medium, which was dependent on laccase, suggesting that the outer membrane may contain a precursor that stimulatates pigment production. To our knowledge, this is the first study addressing these key differences in the growth of C. gattii on different parts of the cactus.
Comparison of Antibody Persistence up to 6 Months after Additional Booster Vaccination with ChAdOx1 nCoV-19 Vaccine
Authors: Suwanwattana Pawita , Han May , Nopsopon Tanawin , Phutrakool Phanupong , Samuthpongtorn Chatpol , Pongpirul Wannarat , Prasithsirikul Wisit , Pongpirul Krit
Published: June 2023

Vaccines are crucial for controlling the COVID-19 pandemic, and booster doses are becoming increasingly important. This study aimed to assess the efficacy of the ChAdOx1 nCoV-19 vaccine from AstraZeneca as a third dose in healthcare workers at different time intervals (one, three, and six months). Two methods to measure immune response—ELISA (EUROIMMUN Medizinische Labordiagnostika AG, Luebeck, Germany) and ELISpot (Mabtech AB, Macka Strand, Sweden)—were used. A total of 170 participants were included in the study. The results showed that while IgG levels decreased at six months compared to levels at one and three months, they were still significantly higher than the baseline. Furthermore, neutralizing levels at three and six months and after the third dose were not significantly different. These findings suggest that the immune response induced by the vaccine was robust and effective for several months. These results have significant implications for public health policymakers, as they provide strong support for booster vaccinations. The ChAdOx1 nCoV-19 vaccine appears to be a reliable option for preventing the spread of COVID-19, and this study provides valuable information for healthcare workers and policymakers in managing the pandemic.
Effect of Agave Fructans on Changes in Chemistry, Morphology and Composition in the Biomass Growth of Milk Kefir Grains
Authors: Moreno-León Germán R. , Avila-Reyes Sandra V. , Villalobos-Espinosa Julieta C. , Camacho-Díaz Brenda H. , Tapia-Maruri Daniel , Jiménez-Aparicio Antonio R. , Arenas-Ocampo Martha L. , Solorza-Feria Javier
Published: June 2023

Prebiotic effects have been attributed to agave fructans through bacterial and yeast fermentations, but there are few reports on their use as raw materials of a carbon source. Kefir milk is a fermented drink with lactic acid bacteria and yeast that coexist in a symbiotic association. During fermentation, these microorganisms mainly consume lactose and produce a polymeric matrix called kefiran, which is an exopolysaccharide composed mainly of water-soluble glucogalactan, suitable for the development of bio-degradable films. Using the biomass of microorganisms and proteins together can be a sustainable and innovative source of biopolymers. In this investigation, the effects of lactose-free milk as a culture medium and the addition of other carbon sources (dextrose, fructose, galactose, lactose, inulin and fructans) in concentrations of 2, 4 and 6% w/w, coupled with initial parameters such as temperature (20, 25 and 30 °C), % of starter inoculum (2, 5 and 10% w/w) was evaluated. The method of response surface analysis was performed to determine the optimum biomass production conditions at the start of the experiment. The response surface method showed that a 2% inoculum and a temperature of 25 °C were the best parameters for fermentation. The addition of 6% w/w agave fructans in the culture medium favored the growth of biomass (75.94%) with respect to the lactose-free culture medium. An increase in fat (3.76%), ash (5.57%) and protein (7.12%) content was observed when adding agave fructans. There was an important change in the diversity of microorganisms with an absence of lactose. These compounds have the potential to be used as a carbon source in a medium culture to increase kefir granule biomass. There was an important change in the diversity of microorganisms with an absence of lactose, where the applied image digital analysis led to the identification of the morphological changes in the kefir granules through modification of the profile of such microorganisms.
Influence of Temperature on Growth of Four Different Opportunistic Pathogens in Drinking Water Biofilms
Authors: van der Wielen Paul W. J. J. , Dignum Marco , Donocik Agata , Prest Emmanuelle I.
Published: June 2023

High drinking water temperatures occur due to climate change and could enhance the growth of opportunistic pathogens in drinking water systems. We investigated the influence of drinking water temperatures on the growth of Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Mycobacterium kansasii and Aspergillus fumigatus in drinking water biofilms with an autochthonous microflora. Our results reveal that the growth of P. aeruginosa and S. maltophilia in the biofilm already occurred at 15.0 °C, whereas M. kansasii and A. fumigatus were able to grow when temperatures were above 20.0 °C and 25.0 °C, respectively. Moreover, the maximum growth yield of P. aeruginosa, M. kansasii and A. fumigatus increased with increasing temperatures up to 30 °C, whereas an effect of temperature on the yield of S. maltophilia could not be established. In contrast, the maximum ATP concentration of the biofilm decreased with increasing temperatures. We conclude from these results that high drinking water temperatures caused by, e.g., climate change can result in high numbers of P. aeruginosa, M. kansasii and A. fumigatus in drinking water systems, which poses a possible risk to public health. Consequently, it is recommended for countries with a more moderate climate to use or maintain a drinking water maximum standard temperature of 25 °C.
A Comparative Study of the Synthesis and Characterization of Biogenic Selenium Nanoparticles by Two Contrasting Endophytic Selenobacteria
Authors: Sans-Serramitjana Eulàlia , Gallardo-Benavente Carla , Melo Francisco , Pérez-Donoso José M. , Rumpel Cornelia , Barra Patricio Javier , Durán Paola , Mora María de La Luz
Published: June 2023

The present study examined the biosynthesis and characterization of selenium nanoparticles (SeNPs) using two contrasting endophytic selenobacteria, one Gram-positive (Bacillus sp. E5 identified as Bacillus paranthracis) and one Gram-negative (Enterobacter sp. EC5.2 identified as Enterobacter ludwigi), for further use as biofortifying agents and/or for other biotechnological purposes. We demonstrated that, upon regulating culture conditions and selenite exposure time, both strains were suitable “cell factories” for producing SeNPs (B-SeNPs from B. paranthracis and E-SeNPs from E. ludwigii) with different properties. Briefly, dynamic light scattering (DLS), transmission electron microscopy (TEM), and atomic force microscopy (AFM) studies revealed that intracellular E-SeNPs (56.23 ± 4.85 nm) were smaller in diameter than B-SeNPs (83.44 ± 2.90 nm) and that both formulations were located in the surrounding medium or bound to the cell wall. AFM images indicated the absence of relevant variations in bacterial volume and shape and revealed the existence of layers of peptidoglycan surrounding the bacterial cell wall under the conditions of biosynthesis, particularly in the case of B. paranthracis. Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) showed that SeNPs were surrounded by the proteins, lipids, and polysaccharides of bacterial cells and that the numbers of the functional groups present in B-SeNPs were higher than in E-SeNPs. Thus, considering that these findings support the suitability of these two endophytic stains as potential biocatalysts to produce high-quality Se-based nanoparticles, our future efforts must be focused on the evaluation of their bioactivity, as well as on the determination of how the different features of each SeNP modulate their biological action and their stability.
Genesis and Geological Significance of Siderite in the First Member of the Nantun Formation of Dongming Sag, Hailar Basin
Authors: Xie Mingxian , Ma Feng , Chen Guangpo , Zheng Xi , Xiao Rong , Zhang Chengjun
Published: June 2023

Multiple siderite beds developed in the first member of the Lower Cretaceous Nantun Formation (K1n1) in the basin. The results show that the siderites in K1n1 of the study area are mostly stratiform or massive, with three micromorphological features (dense micronized crystals, bands, and paragenesis with quartz and calcite). The siderite beds are mainly composed of siderite, clay, quartz, calcite, and feldspar. Under the microscope, charcoal, algal fossils, granular pyrite crystals, vein-like siliceous bands, etc., were observed. The oxides in the siderite beds include Fe2O3, SiO2, Al2O3, etc. The trace elements are typically characterized by high Mn and Be contents; low Sr/Ba, Th/U, and Al/Ti ratios; and high V/Cr ratios. These indicate weakly reducing, freshwater depositional paleoenvironments. The δ13Cv-PDB and δ18Ov-PDB values of siderite are −0.20–1.11‰ (mean: 0.62‰) and −18.22‰ to −10.14‰ (mean: −14.23‰), respectively, which shows that the carbon in siderite came mainly from carbonate dissolution. The Fe-bearing rocks in the source area migrated to the basin after undergoing physical and chemical weathering, and when the resultant Fe2+ concentration reached saturation, Fe2+ combined with CO32− in the water bodies to form authigenic siderite.