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Abstract Gears are important mechanical parts for transmitting power and play an increasingly important role in the machinery industry. The electric vehicle industry developed rapidly and became a vital development field of the automotive industry over the past few years. The conversion of energy increases the requirements for electric vehicle transmissions, which promotes the development of high-speed and low-noise transmission gear. This paper elaborates on the research progress of high-speed and low-noise gear finishing methods. Firstly, this review analyses the machining requirements, finishing, and specific machining technologies of high-speed and low-noise gears. The importance of gear grinding and honing in high-speed and low-noise gear machining is highlighted. Secondly, the applications of gear grinding and honing in gear modification, error compensation, and texture control are analyzed. Furthermore, the role of precision machining technology in improving gear performance is clarified. Finally, the design and processing methods of the modified tooth flank for gear modification are summarized. In addition, the influence of tooth surface texture on noise is described, and the texture change methods are explored. The well-known open problems of gear finishing are finally identified, and some new research interests are also pointed out. This review will provide valuable references for further research on gear finishing.

Abstract The current research on noncircular hobbing mainly focuses on the linkage model and motion realization. However, the intermittent cutting characteristics of hobbing would increase uncertainties in the manufacturing process. In this paper, a hobbing machining model with tool-shifting characteristics was proposed to solve the problems of cutting force fluctuation and inconsistency of tooth profile envelope accuracy at different positions of the pitch curve in noncircular gear hobbing. Based on the unit cutting force coefficient method, the undeformed chip volume generated by interrupted cutting was used to characterize the fluctuation trend of the hobbing force. The fluctuation characteristics of the cutting force generated by different hobbing models were compared and analyzed. Using the equivalent gear tooth and hob slotting numbers, an analysis model of the tooth profile envelope error of the noncircular gear was constructed. Subsequently, the tooth profile envelope errors at different positions of the pitch curve were compared and analyzed based on the constructed model. The transmission structure of the electronic gearbox was constructed based on the proposed hobbing model, and the hobbing experiment was conducted based on the self-developed noncircular gear CNC hobbing system. This paper proposes a hobbing method that can effectively suppress the fluctuation of the peak and whole circumference cutting force and reduce the maximum envelope error of the whole circumference gear teeth.

Squirrels of temperate zones commonly store nuts or seeds under leaf litter, in hollow logs, or even in holes in the ground; however, in the humid rainforests of Jianfengling in Hainan, South China, we show that some flying squirrels cache elliptical or oblate nuts by hanging them securely in vegetation. These small flying squirrels were identified as Hylopetes phayrei electilis (G. M. Allen, 1925) and Hylopetes alboniger (Hodgson, 1870), in video clips captured of their behavior around focal nuts. Squirrels chewed grooves encircling ellipsoid nuts or distributed on the bottoms of oblate nuts, and then used these grooves to fix nuts tightly between small twigs 0.1–0.6 cm in diameter that were connected at angles of 25–40°. The grooves carved on the nuts (concave structure) connected with Y-shaped twigs (convex structure) and thus firmly affixed the nuts to the plant in a way similar to a mortise-tenon joint used in architecture and carpentry. Cache sites were on small plants located 10–25 m away from the closest potentially nut-producing tree, a behavior that likely reduces the discovery and consumption of the nuts by other animals. The adaptive squirrel behavior that shapes and fits nuts between twigs seems to be directed at providing more secure storage that increases food supply during dry periods in a humid tropical rainforest. In addition to providing such benefits for the squirrels, we suggest that this behavior also impacts the distribution of tree species in the forest.

Topological modification of gear surface is used to achieve better meshing transmission performance and accuracy. However, in the traditional gear modification grinding process, the topological modified tooth surface is usually simplified to the control of profile modification and lead modification, which is difficult to achieve the coincidence of machining and design. To solve this problem, a flexible topology flank modification method based on polynomial interpolation function is proposed in this paper. Based on the gear meshing principle and polynomial interpolation technology, the method realizes a topological modification of the gear by controlling multiple axes’s position on the machine tool. Firstly, a gear grinding model of worm grinding wheel with controllable grinding precision is established. Then the axial, radial and tangential motions of worm grinding wheel is expressed as fifth order polynomials, and the polynomial coefficients is optimized by particle swarm optimization algorithm. Finally, numerical simulation was used to compare the proposed method with the sensitivity matrix method, and the results showed that the proposed method had better optimization effect. The new flexible topological modification method can realize the topological modification machining by controlling the motion of each axis of the tool, and the problem that the topological modification machining does not match the design is solved.

Aiming at current problems of low gear shaping efficiency and large cutting force fluctuations in non-circular gears，and based on the gear shaping cutting force modeling and the relationship established between the cutting force and the cutting area，the article proposes circular feed rate optimization method based on constant cutting force constraint. To improve the processing efficiency of the workpiece and reduce the fluctuation of the cutting force，with the machine parameters and the constant cutting area as the constraints，and taking the curvature radius of the pitch curve as the segmented basis，an optimization model of variable circumferential feed is established. Through the analysis of the third-order elliptic gear slotting example，the effectiveness of the variable circle feed optimization model is verified. The segmented optimization avoids frequent and severe changes in the speed of each axis of motion，and realizes the optimization of the processing parameters of non-circular gears.

Hobbing is one of the most important gear machining process，forming process of which is complicated and involves a large number of cutting parameters. In order to quantify the influence of machining parameters on the cutting force in hobbing process，a method for predicting the cutting force of gear hobbing based on three-dimensional （3D） geometric simulation is studied. The relative position and motion relationship between hob and workpiece are determined according to the geometric parameters and cutting parameters of hob and workpiece， the 3D simulation of hobbing process is realized in CAD environment，and the 3D model of undeformed chips is obtained. According to the selected cutting force model，the instantaneous cutting force of a single cutting edge is calculated by using the cross-section size of undeformed chips model，and the overall cutting force process of hobbing is obtained. The influence of different cutting parameter on hobbing cutting force is analyzed quantitatively. The predictive model helps to optimize the design of the gear hobbing process to improve the quality and efficiency of the machining and reduce the cost.

In order to process the workpiece with internal gearing power honing technology，the honing wheel is usually dressed with the customized diamond dressing wheel corresponding to the workpiece. A method of internal gearing power honing modification based on flexible dressing of honing wheel is proposed to increase the commonality of diamond dressing wheel，reduce the cost of internal gearing power honing technology. Firstly，the tooth surface mathematical model of dressing and honing is established according to the motion relationship of each axis of gear honing machine. Then，the multi axis linkage of honing wheel dressing is expressed in polynomial form，the influence of each axis movement on the final workpiece tooth surface is expressed as sensitivity matrix，and the polynomial coefficients of each axis are optimized with the target modification tooth surface. Finally，the final tooth surface of the workpiece is calculated according to the optimized motion parameters of honing，and the tooth contact is analyzed. The results show the standard diamond dressing wheel can be used for flexible dressing of honing wheel，and the effective modification workpiece can be machined finally.

Gear flank twist occurs when threaded wheel grinds crowning lead modified helical gears, which reduces gear machining accuracy. To overcome this problem, a flank twist compensation method based on flexible electronic gearbox is proposed in this paper, the method can reduce the degree of twist and improve gear machining accuracy. Firstly, flank equations of gear and threaded wheel are established, coordinates and normal vectors of gear flank are used to represent twist. Secondly, coordinate transformation matrix between workpiece and tool coordinate system is established based on multi-body system theory and homogeneous coordinate transformation, and relationship between coordinates and normal vectors of gear flank and master-slave axis (B-axis, C-axis, X-axis, Y-axis, Z-axis) movement amount is obtained by inverse kinematics and electronic gearbox, then master-slave axis movement compensation amount between crowning lead modified flank and twisted flank is obtained. Finally, twist is compensated by compensating for master-slave axis movement amount, and flank contact analysis based on KISSsoft is carried out to observe normal force and contact stress of flanks. This paper uses inverse kinematics and electronic gearbox to realize flank twist compensation, which makes up for long period and high cost of traditional flank twist compensation by changing shape of threaded wheel. Simulation results show that this method can effectively compensate for flank twist and improve accuracy and efficiency when threaded wheel grinds crowning lead modified helical gears.

Extensive and high residue variations in enrofloxacin (ENR) exist in different aquatic products. A novel quantitative method for measuring ENR using high-performance liquid chromatography–tandem mass spectrometry was developed employing enrofloxacin-d5 (ENR-d5) and enrofloxacin-d3 (ENR-d3) as isotope surrogates. This reduced the deviation of detected values, which results from the overpass of the linear range and/or the large difference in the residue between the isotope standard and ENR, from the actual content. Furthermore, high residue levels of ENR can be directly diluted and re-calibrated by the corresponding curve with the addition of high levels of another internal surrogate without repeated sample preparation, avoiding the overflow of the instrument response. The validation results demonstrated that the method can simultaneously determine ENR residues from MQL (2 µg/kg) to 5000 × MQL (method quantification limit) with recoveries between 97.1 and 106%, and intra-precision of no more than 2.14%. This method realized a wide linear calibration range with dual deuterated isomers, which has not been previously reported in the literature. The developed method was successfully applied to the analysis of ENR in different aquatic products, with ENR residue levels varying from 108 to 4340 μg/kg and an interval of precision in the range of 0.175~6.72%. These results demonstrate that batch samples with a high variation in ENR residues (over the linear range with a single isotope standard) can be detected by the dual isotope surrogates method in a single sample preparation process.

This paper proposes a method to study the machining error when one is generating gear grinding based on the mapping relationship between the grinding wheel surface and the tooth flank. The profile of the grinding wheel after grinding is collected, and the theoretical tooth flank is derived according to a model of generating gear grinding. By comparing the normal deviation of the theoretical tooth flank with the measured tooth flank, the machining error characteristics are identified. Firstly, the mathematical model of generating gear grinding is established according to a multi-body theory and coordinate transformation. Secondly, the experiments of the lead modification for helical gear were performed on a YW7232 CNC gear grinding machine. The tooth flank twist compensation function was turned off in experiments No. 1–No. 3, and it was turned on in experiments No. 4–No. 6, while the other process parameters kept the same. Then, the corresponding theoretical tooth flank data were derived from the grinding wheel surface which were measured using the laser profilometer LJ-V7000. Finally, the machining error characteristics were obtained by analyzing the difference between the theoretical and measured tooth flank deviations. The result of this paper can provide theoretical and practical references for the improvement of the gear grinding accuracy and gear modification design.

To improve the stability and accuracy of non-circular gear transmission, a beveloid non-circular gear transmission scheme was developed to reduce the meshing impact and achieve backlash adjustment. When using the beveloid rack as the medium, the instantaneous contact line of the beveloid non-circular gear pair was shown to be a straight line, and the tooth surface was shown to be a ruled surface based on the transmission relationship between the rack centerline and the non-circular pitch curve. The zero-modification method was employed to develop the beveloid non-circular gear. Further, the generation method for the tooth profile of the modified non-circular gear was reviewed, and a digital solid model was developed for the beveloid non-circular gear. The physical contact simulation method was used to analyze the meshing backlash, and the influence of the axial displacement adjustment on the meshing backlash of the gear pair was obtained. By considering a pair of beveloid elliptic gears as an example, machining and transmission experiments were conducted, with results showing smooth gear-pair meshing and the anticipated backlash adjustment effect.

Both adenosine triphosphate (ATP) and glucose are important to human health, and their abnormal levels are closely related to angiocardiopathy and hypoglycaemia. Therefore, the simultaneous determination of ATP and glucose with a single test mode is highly desirable for disease diagnostics and early recognition. Herein, a new fluorescence on/off switch sensing platform is developed by carbon nanodots (CNDs) to detect ATP and glucose simultaneously. The fluorescence of CNDs can be quenched by Cu2+ and hydrogen peroxide (H2O2), due to the formation of hydroxyl radicals (·OH) produced in the Cu-Fenton reaction. Based on the high affinity of Cu2+ with ATP, the fluorescence of CNDs will recover effectively after adding ATP. Additionally, glucose can be efficiently catalyzed by glucose oxidase (GOx) to generate H2O2, so the platform can also be utilized to analyze glucose. Under optimum conditions, this sensing platform displays excellent sensitivity and the linear ranges are from 0.1 to 7 μM for ATP with a limit of detection (LOD) of 30.2 nM, and from 0.1 to 7 mM for glucose with a LOD 39.8 μM, respectively. Benefiting from the high sensitivity and selectivity, this sensing platform is successfully applied for simultaneous detection of ATP and glucose in human serum samples with satisfactory recoveries.

Background: Reducing exposure to risk factors and screening represent 2 major approaches to gastric cancer (GC) prevention, but public knowledge GC risk factors and screening behaviour remain unknown. We aimed to investigate public awareness of GC risk factors, adherence to screening, and barriers hindering screening practices in China. Methods: This community-based household survey was conducted within Shijiazhuang, China, and 1490 residents were recruited through a multistage stratified cluster random sampling approach. A self-administered questionnaire was completed which consisted of three sections: demographics, awareness of GC risk factors, and personal screening behaviours. Factors associated with knowledge of risk factors and screening behaviours were evaluated using binary logistic regression analysis. Results: The mean risk factor awareness score of 12 (7, 15) revealed insufficient knowledge in 51.1% of participants. Dietary lifestyle factors were better understood than physical activity and weight-related factors. Marital status (OR 1.967; 95% CI 1.415 to 2.734), higher income (OR 1.197; 95% CI 1.010 to 1.418), and a history of upper gastrointestinal problems (OR 0.048; 95% CI 1.002 to 1.311) were associated with higher awareness. Merely 21.5% underwent GC screening, with higher rates linked to older age (OR 1.642; 95% CI 1.418 to 1.902), higher education (OR 1.398; 95% CI 1.176 to 1.662), a history of upper gastrointestinal problems (OR 3.842; 95% CI 2.833 to 5.209), and moderate (OR 2.077; 95% CI 1.352 to 3.191) and high (OR 2.529; 95% CI 1.311 to 4.878) perceived GC risk. Notably, participants commonly refused gastroscopy due to the absence of symptoms or signs. Conclusions: In Shijiazhuang, more than half of participants demonstrated inadequate knowledge of GC risk factors, and screening participation rates were remarkably low. This emphasizes the need for targeted interventions to enhance GC awareness and significantly improve screening rates. [ABSTRACT FROM AUTHOR]

Intracranial hemorrhage (ICH), the second most common subtype of stroke, exacerbates the disruption of the blood-brain barrier (BBB), leading to vasogenic edema, plasma protein extravasation, and infiltration of neurotoxic substances. The clearance capacity of the brain plays a crucial role in maintaining BBB homeostasis and facilitating patient recovery after hemorrhage. This study aimed to investigate the effect of circadian rhythms on BBB function, neuronal damage, and clearance capabilities. The transwell model and hemoglobin were co-cultured to simulate the BBB environment after ICH. After intervention with different light groups, neuronal apoptosis was determined, glial phagocytosis was analyzed, the expression of endogenous clearing-related proteins aquaporin 4 (AQP4) and low-density lipoprotein receptor-related protein 1 (LRP1) was detected by western blotting and immunofluorescence dual standard method, and the expression of the tight junction protein occludin and melatonin receptor 1A (MTNR1A) was quantitatively analyzed. Circadian rhythms play a key role in maintaining the integrity of the BBB, reducing oxidative stress-induced neuronal damage, and improving microglial phagocytosis. Meanwhile, the expression of occludin and MTNR1A in neurovascular unit (NVU) co-cultured with hemoglobin improved the expression of AQP4 and LRP1, the key proteins in the NVU's endogenous brain clearance system. Circadian rhythm (alternating black and white light) protects the NVU BBB function after ICH, promotes the expression of proteins related to the clearance of the hematoma, provides new evidence for the clinical treatment of patients recovering from ICH, and improves the circadian rhythm to promote brain metabolism and hematoma clearance. [ABSTRACT FROM AUTHOR]

Abstract Metal halide perovskites are attractive for optoelectronic applications, but the existing solution-based synthetic methods rely on hazardous solvents and lack reproducibility. To overcome these challenges, solvent-free mechanochemical synthesis of perovskites can be conducted, although traditional opaque ball milling equipment hinder real-time monitoring of the reaction progress. Herein, mechanochemistry was performed with time-lapsed in situ (TLIS) measurements to elucidate the optical properties during the synthesis. The TLIS spectrometer enabled real-time observation of the impact of varying the compositions on the absorption properties of formamidinium/methylammonium lead iodide (FA x MA1-x PbI3, x = 0 to 1) and facilitated optimization of the synthesis duration. Moreover, we can accelerate the evaluation and directly observe the effects of different synthetic strategies for enhancing the photoluminescence quantum yield and stability of the perovskites, providing near-infrared (NIR) emitting tin-based perovskites FASnI z Br3-z (where z = 0 to 3) with core-shell structures. Intriguingly, halide ion migration was deduced in lead-free double perovskites Cs2Na y Ag1-y BiCl6 (y = 0 to 1.0) at room temperature during aging after mechanochemical activation. Our work provides insights into the mechanochemistry of compounds with low thermodynamic barriers.

As a non-classical post-translational modification, O-linked β-N-acetylglucosamine (O-GlcNAc) modification (O-GlcNAcylation) is widely found in human organ systems, particularly in our brains, and is indispensable for healthy cell biology. With the increasing age of the global population, the incidence of neurodegenerative diseases is increasing, too. The common characteristic of these disorders is the aggregation of abnormal proteins in the brain. Current research has found that O-GlcNAcylation dysregulation is involved in misfolding or aggregation of these abnormal proteins to mediate disease progression, but the specific mechanism has not been defined. This paper reviews recent studies on O-GlcNAcylation's roles in several neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, Machado-Joseph's disease, and giant axonal neuropathy, and shows that O-GlcNAcylation, as glucose metabolism sensor, mediating synaptic function, participating in oxidative stress response and signaling pathway conduction, directly or indirectly regulates characteristic pathological protein toxicity and affects disease progression. The existing results suggest that targeting O-GlcNAcylation will provide new ideas for clinical diagnosis, prevention, and treatment of neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Background: Though the prevalence of diabetes is set to increase, most serious game solutions typically target patient self-management and education. Few games target health care professions education, and even fewer consider the factors that may increase their efficacies. The impact of facilitation, a prominent feature of health professions education, is examined in the context of a rehearsal-based diabetes management serious game. Objective: In this mixed methods, open-label, superiority randomized controlled trial, we compare student performance, attitudes, and perceptions of a rehearsal-based diabetes management game for health care professionals. Methods: Student participants were randomized into 2 groups to play a diabetes management game. The control group played the game alone, and the intervention group played the same game alongside a facilitator tasked to moderate overall challenge levels and address queries. Both groups were administered the Flow Short Scale, a 13-item measure rated on a 7-point Likert scale ranging from 1 ("not at all") to 7 ("very much") immediately after the game. Students were then invited to voluntary focus group discussions to elicit their attitudes and perceptions of the game. Findings were subject to between-group comparisons and inductive thematic analysis respectively. Results: A total of 48 (26 control, 22 intervention) clinical-year undergraduates from the Lee Kong Chian School of Medicine in Singapore participated in this study, with 18 continuing to the focus group discussions. Flow Short Scale results indicated the superiority of the intervention group for overall flow (t 46=–2.17, P=.04) and the absorption subdomain (t 46=–2.6, P=.01). Qualitative results indicated students viewed facilitation as helpful and appropriate, and were able to identify improvable elements of the game's theoretical foundations and overall design. Conclusions: While serious games are efficacious means of rehearsing previously learned knowledge, facilitation allows for their efficiency to be greatly increased. Such increases are likely crucial in the coming years with the increased digitization of health care professions education and the prevalence of diabetes. Trial Registration: ClinicalTrials.gov NCT05637749; https://www.clinicaltrials.gov/study/NCT05637749 [ABSTRACT FROM AUTHOR]