Simulation of Binder Jetting and Analysis of Magnesium Alloy Bonding Mechanism.

Binder jetting (3DP) is a kind of additive manufacturing at room temperature and atmospheric environment, which can reduce the risk of magnesium alloy forming. Magnesium alloy powder is bonded to a certain structure by a binder, so the appropriate binder is very important in 3DP. In this study, according to the characteristics of magnesium alloy, a simple and easy-to-obtain water-based low-molecular alcohol binder was used to reduce the difficulty of magnesium alloy 3DP. Additionally, we use COMSOL Multiphysics simulation software to establish a simulation model of the movement and deposition process of the binder. The results show that the increase in jet velocity will increase the quality and saturation of droplets. More importantly, the larger the jet velocity is, the larger the spreading width of the binder droplet after impacting the powder bed, which seriously affects the dimensional accuracy of the green part. In addition, lower binder saturation will weaken the formation of interparticle bonding neck and cannot form a stable structure. Furthermore, we analyzed the bond reactants of the binder and magnesium alloy powder, which eventually decompose into MgO, and the experimental results show that the final sintered sample has considerable performance.

From a spark to a sweeping fire: An integrative conceptual review of group turnover and a theoretical exploration of its development.

The phenomenon of group turnover has generated substantial yet disconnected scholarly interests. Despite valuable insights gained from the collective turnover literature as well as parallel research concerning related or coordinated quitting, a holistic understanding of the unique group turnover phenomenon is needed, both to synthesize existing research across multiple domains and disciplines and to kindle new inquiries regarding its dynamic nature and developmental process. To this end, we begin by conducting an integrative review of research relating to group turnover, reinterpreting it by identifying its common pathways as a function of varying triggers, temporal patterns, and departure destinations. We then leverage the groups literature to explicate group turnover's self-reinforcing and dynamic nature and propose a three-dimensional Interdependence, Temporality, and Emergence (ITE) framework that accounts for its developmental process. Using this framework, we develop an illustrative set of propositions regarding how ITE-related group properties affect the extent to which individual departures might escalate into group turnover of a larger scale and faster speed. Our emphasis on groups as a unique unit of reference thus provides an important conceptual refinement and extension for understanding collective turnover-shifting from a static focus on aggregate exit (rates) to a dynamic focus on the often-coordinated, temporally evolving nature of multiple group member quit events. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Clinical Application of Dark-blood Imaging in Head and Neck CT Angiography: Effect on Image Quality and Plaque Visibility.

RATIONALE AND OBJECTIVES: The aim of this study was to explore the potential of a newly developed dark-blood imaging technique to improve image quality and plaque visibility in head and neck computed tomography (CT) angiography. MATERIALS AND METHODS: Patients who underwent triphasic head and neck CT angiography scans from August 2021 to March 2023 were retrospectively enrolled (mean age 67.23 ± 10.81 [SD] years, range 43-85 years, 64.7% male). The CT protocol consists of pre-contrast, arterial and delayed phases. Dark-blood images were postprocessed with the contrast-enhancement boost (CE-boost) technique. The quantitative assessment involved evaluating the CT value, image noise, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) of calcified plaque and non-calcified plaque. The plaque CNR relative to the vessel lumen (CNRplaque-lumen), vessel wall (CNRplaque-wall), and adjacent muscle (CNRplaque-muscle) was respectively calculated. Two experienced radiologists independently evaluated the CT images (5, best; 1, worst) by four characteristics including calcified plaque visibility, non-calcified plaque visibility, diagnostic confidence, and overall image quality. Inter-rater variability was also evaluated. The artery stenosis rate and plaque burden on dark-blood images were measured and compared with arterial phases. The intraclass correlation coefficient (ICC) was used for consistency analysis. The diagnostic accuracy of dark-blood images for the stenosis rate was evaluated by the area under the curve (AUC). RESULTS: A total of 43 patients with 54 calcified plaques and 34 non-calcified plaques were assessed in this study. When compared with pre-contrast and delayed phase, dark-blood images yielded significantly higher CNRplaque-lumen and CNRplaque-muscle of calcified (219.79 ± 159.20 and 181.23 ± 112.12, respectively) and non-calcified (30.30 ± 29.11 and 6.28 ± 4.75, respectively) plaques (all p < 0.001). Calcified plaque SNR of dark-blood showed equal or slightly lower than other phases (p > 0.05 or p = 0.02). A major increase was observed in the non-calcified plaque SNR of dark-blood compared to the arterial phase (5.56 ± 3.71 vs. 4.23 ± 3.56, p = 0.02), although there were no apparent differences compared to pre-contrast and delayed phases (p > 0.05). In subjective analyzes, the calcified plaque visibility (4.99 ± 0.07), non-calcified plaque visibility (4.62 ± 0.48), overall image quality (4.81 ± 0.34), and diagnostic confidence (4.74 ± 0.36) in dark-blood images dominated the highest scores (p < 0.001). The subjective scores of radiologists exhibited good consistency (all kappa value>0.7). The dark-blood image and the arterial phase image exhibited good consistency in identifying the stenosis rate (p < 0.001). In the evaluation of plaque burden, the interobserver agreement for dark-blood images was higher compared to arterial phase images (ICC = 0.870 vs. 0.729). CONCLUSIONS: Compared to conventional triphasic head and neck CT angiography, the CE-boost derived dark-blood imaging demonstrated a significant improvement in image quality and visibility for both calcified and non-calcified plaque assessment.

Improvement of Mechanical Properties of Personalized Insole Manufactured with Selective Laser Sintering Based on Process Parameter Optimization and Cell Structure Design.

Personalized insoles manufactured with selective laser sintering (SLS) technology are popular especially for exercisers and patients with foot diseases. However, insufficient strength and toughness of personalized insoles would result in crack and even fracture. To address these deficiencies and fill the research shortages in this area, optimization of process parameters and design of cell structures are conducted to improve the mechanical performance of insoles in this topic. First, six sets of process parameters in terms of energy density were designed for parameter optimization. The energy density of 0.08 J/mm2 was affirmed to be the finest selection. Then, specific cell structures featuring both whale shark and ancient soldier armor (WS structures for short) with various curvature radius were established to act on the bottom of the insole to further strengthen the personalized insoles. It was shown that the WS14 structure exhibited the best performance characteristics. Finally, a personalized insole with the array of WS14 structures was developed with SLS under the optimum energy density of 0.08 J/mm2. Finite element method analysis and exercising testing were performed to evaluate the insole performance. The result reveals that a more uniform stress distribution is attained of the WS14 personalized insole, and the fracture problem is indeed solved.

Optimization of Selective Laser Sintering Process Parameters Based on PA12 Powders for Bone Tissue Scaffolds.

In selective laser sintering (SLS), process parameters are essential to fabricate outstanding mechanical properties products. In this research, process parameters of porous Polyamide 12 (PA12) scaffold were investigated for the sake of obtaining superior mechanical properties. The area energy density (AED) determined by laser power, scanning speed, and scanning space was employed as the main index to assess process parameters. Six groups with different AED were planed, and then cubic and cylindrical samples were modeled and fabricated with PA12 powders via SLS. Afterward, mechanical properties of the samples were measured and studied to achieve optimum parameters. After a detailed comparison of micrograph, density, dimensional accuracy, and mechanical properties of samples under different AED, laser power of 16 W, scanning speed of 2500 m/s, and scanning space of 0.12 mm were found to be the optimum parameters. Further, a 60% uniform porosity scaffold was fabricated with the optimum parameters to measure mechanical properties for evaluating the optimized results, which were elastic modulus of 87.79 MPa, yield strength of 8.25 MPa, and Poisson's ratio of 0.3. Finite element simulation was also performed, and the results exhibited a good agreement with the experimental behaviors.

Characterization of PA12/HA composite scaffolds based on selective laser sintering.

Composite scaffolds have been extensively studied in bone tissue engineering, which can achieve excellent properties that cannot be obtained by a single material. In this study, the effect of hydroxyapatite (HA) on the reliability of polyamide 12 (PA12) scaffold for bone graft was explored in terms of mechanical and biological properties. Thermal properties testing showed that no physical or chemical reaction occurs in the prepared PA12/HA composite powders. Further, compression experiments showed that adding a small amount of HA promoted the mechanical properties of the scaffold, while excessive HA results in agglomeration and impairs the PA12/HA scaffold. For the scaffolds with the porosity of 65%, the 96% PA12/4% HA scaffold has a 7.3% higher yield strength and a 13.5% higher compressive modulus than the pure PA12 scaffold while the strength of the 88% PA12/12% HA scaffold decreases by 35.6%. Furthermore, contact angle and CCK-8 tests confirmed that 96% PA12/4% HA scaffold effectively improved the hydrophilicity and biocompatibility of the scaffold. Its OD value on the 7th day is 0.949, which is significantly higher than that of other groups. In summary, PA12/HA composites have good mechanical properties and biocompatibility, which can be used as an effective strategy in bone tissue engineering.

Mechanical properties and failure mechanisms of polyamide 12 gradient scaffolds developed with selective laser sintering.

Developing a functional gradient scaffold compatible with the fantastic biological and mechanical properties of natural bone tissue is imperative in bone tissue engineering. In this work, the stretch-dominated (cubical and circular) and bending-dominant (diamond and gyroid) pore styles were employed to design custom-graded scaffolds based on the curve interference method and then were fabricated by selective laser sintering (SLS) using polyamide 12 (PA12) powder. Subsequently, the mechanical behavior, failure mechanism, and energy absorption performance of porous structures were investigated via compression experiments and finite element (FE) simulation. The results indicated that the stretch-dominated radial gradient structures entire exhibited transverse shear failure and the bending-dominant radial gradient structures whole exhibited progressive destruction, while all of the axial gradient scaffolds suffered a predictable layer-by-layer fracture. Among them, the bending-dominated radial gradient structure of gyroid had been proven to sustain stronger deformability and energy absorption capacity. Meanwhile, the FE method powerfully predicted the mechanical behavior of the scaffold, and this research thereby possessed significant implications for the development of bone tissue engineering.

Safe reinforcement learning under temporal logic with reward design and quantum action selection.

This paper proposes an advanced Reinforcement Learning (RL) method, incorporating reward-shaping, safety value functions, and a quantum action selection algorithm. The method is model-free and can synthesize a finite policy that maximizes the probability of satisfying a complex task. Although RL is a promising approach, it suffers from unsafe traps and sparse rewards and becomes impractical when applied to real-world problems. To improve safety during training, we introduce a concept of safety values, which results in a model-based adaptive scenario due to online updates of transition probabilities. On the other hand, a high-level complex task is usually formulated via formal languages, including Linear Temporal Logic (LTL). Another novelty of this work is using an Embedded Limit-Deterministic Generalized Büchi Automaton (E-LDGBA) to represent an LTL formula. The obtained deterministic policy can generalize the tasks over infinite and finite horizons. We design an automaton-based reward, and the theoretical analysis shows that an agent can accomplish task specifications with the maximum probability by following the optimal policy. Furthermore, a reward shaping process is developed to avoid sparse rewards and enforce the RL convergence while keeping the optimal policies invariant. In addition, inspired by quantum computing, we propose a quantum action selection algorithm to replace the existing [Formula: see text]-greedy algorithm for the balance of exploration and exploitation during learning. Simulations demonstrate how the proposed framework can achieve good performance by dramatically reducing the times to visit unsafe states while converging optimal policies.

Application of binasal speculum in endoscopic endonasal surgery for lesions in sellar region.

Objective: This study aims to access the efficacy of the binasal speculum in endoscopic endonasal surgery by evaluating clinical outcomes and examining its utility through process-based performance measures in both surgeons and assistants. Methods: A total of 59 patients with lesions in sellar region who underwent endoscopic endonasal surgery with the binasal speculum between September 2020 and March 2023 were included in this study. We assessed the extent of resection and documented postoperative nasal condition. Both surgeons and assistants completed post-use surveys to exam the utility of the binasal speculum and provide an overall grading. Results: Gross total resection (GTR) was successfully achieved in 94.9% (56/59) of patients, with subtotal resection (STR) observed in 5.1% (4/59) of patients. Intraoperative cerebrospinal fluid (CSF) leakage occurred in 23.7% (14/59) of cases, and nasoseptal flap (NSF) reconstruction was required in 55.9% (33/59) of cases. The nasal airway patency rapidly recovered within 14 days in a significant majority of patients (94.9%, 56/59). Moreover, olfactory function was regained within three months postoperatively by 91.5% (54/59) of patients. The overall post-use survey mean score was 26.4. Specifically, surgeons had a mean score of 26.5, while assistants had a slightly lower mean score of 26.2. The mean overall grading for the binasal speculum was 3. Both surgeons and assistants provided a mean overall grading of 3. Conclusion: The binasal speculum provides nasal mucosa protection and reduces the risk of an endoscopic lens clouded by mucosa or blood. It plays a crucial role in accurate guidance and facilitates the swift delivery of surgical instruments, particularly in left-blinded nasal cavities. The binasal speculum reduces the learning curve, especially for endoscopic surgeons with limited experience, while enhancing collaboration and coordination between surgeons and assistants during surgery. Both surgeons and assistants rated the overall utility of the binasal speculum as "excellent."

Mechanical and permeability properties of porous scaffolds developed by a Voronoi tessellation for bone tissue engineering.

Irregular porous structures for guided bone regeneration applications have gained increasing attention as they are similar to human bone and more suitable for bone tissue growth. However, pore irregularity as a critical characteristic has been poorly explored. This study proposed a method for parametrically designing porous scaffolds based on a Voronoi tessellation which were manufactured by selective laser sintering (SLS) using the polyamide 12 (PA12) material. The deformation mechanism and energy absorption properties of the prepared Voronoi scaffolds were investigated by quasi-static compression experiments. The results demonstrated that the Voronoi scaffold underwent bending deformation subsequent to transverse expansion under compression, and the Voronoi scaffold simultaneously had been indicated to be effective in improving the carrying capacity and energy absorption performance. Subsequently, computational fluid dynamics (CFD) and cell proliferation tests were introduced to comprehensively assess the influence of the scaffolds on cell growth. CFD analysis showed that the permeability of the surveyed scaffolds is between 3.65 × 10-8 and 12.05 × 10-8 m2 similar to that of natural cancellous bone. The cell test expressed that the scaffold exhibits good cell activity, which can be used to promote cell adhesion and migration with superior potential for development and application.

Room-temperature polariton lasing in GaN microrods with large Rabi splitting.

Room-temperature polariton lasing is achieved in GaN microrods grown by metal-organic vapor phase epitaxy. We demonstrate a large Rabi splitting (Ω = 2g0) up to 162 meV, exceeding the results from both the state-of-the-art nitride-based planar microcavities and previously reported GaN microrods. An ultra-low threshold of 1.8 kW/cm2 is observed by power-dependent photoluminescence spectra, with the linewidth down to 1.31 meV and the blue shift up to 17.8 meV. This large Rabi splitting distinguishes our coherent light emission from a conventional photon lasing, which strongly supports the preparation of coherent light sources in integrated optical circuits and the study of exciting phenomena in macroscopic quantum states.

Impact of apical and mid-ventricular transmural infarcts in patients with acute myocardial infarction determined by using late gadolinium enhancement combined with feature tracking magnetic resonance.

Background: To analyze the relationship between left ventricular (LV) myocardial strain and transmurality of myocardial infarction at three circular sections (basal, mid-ventricular, apical) by a combined analysis of cardiac magnetic resonance feature tracking (CMR-FT) and late gadolinium enhancement (LGE) information in a cohort of ST-elevation acute myocardial infarction (STEMI) patients after primary percutaneous coronary intervention (PPCI). Methods: In all, 136 patients with STEMI who underwent PPCI within 12 hours of symptom onset were included. CMR-FT and LGE-MRI were performed 5±2 days after PCI for measuring regional and global myocardial strain indexes and transmural extent. Multivariate regression analysis and Kaplan-Meier survival analysis were performed. Results: Regional radial and circumferential strain decreased with increasing transmurality of myocardial infarction irrespective of basal, mid-ventricular, or apical segments. Segmental longitudinal strain was significantly decreased in the transmural infarcted segments only at the apical and mid-ventricular levels. A significant correlation was found between the number of transmural infarcts and global strain parameters in the apical and mid-ventricular portions. Transmural infarcted segments in apical + mid-ventricular portions >2 was related to an increased risk of cardiac events in patients with STEMI following PPCI than those ≤2. GLS was found to be an independent predictor of cardiac events in these patients. Conclusions: The number of transmural infarcted segments in apical + mid-ventricular portions affects LV global function and prognosis. Global longitudinal strain (GLS) is a significant predictor of adverse events after PPCI for STEMI. Morphologic and functional data fused to study complex pathophysiologic processes of LV early after STEMI may help in risk stratification of patients.

The dark side of creativity: Neural correlates of malevolent creative idea generation.

Malevolent creativity, as one dark side of creativity, refers to manifestations people propose to harm themselves or others materially, mentally, or physically in an innovative way. This study aimed to explore the neural correlates of malevolent creative idea generation using task-based static and dynamic functional connectivity (FC) analysis across different time periods. We collected 34 participants who performed malevolent creativity task (MCT), benevolent creativity task (BCT), and realistic presented problems task (RPPT) in the fMRI scanner. The static connectivity analysis showed lower FC strength and global and local efficiency between the dorsal somatomotor network (dSMN), visual network (VN), default mode network (DMN), and reward network (RN) in MCT and RPPT than BCT. Dynamic connectivity analysis showed higher dynamic network reconfiguration in the DMN during MCT than BCT and RPPT. The behavioral results showed higher anxiety, anger, and lower pleasure in MCT than in BCT and RPPT. These findings indicate that the dSMN, VN, RN, and DMN are specifically involved in malevolent creative idea generation. Our findings provide the neural correlates of malevolent creative idea generation using neuroimaging techniques for the first time, which provides insight into the future study of malevolent creativity.

Embeddedness and perceived oneness: Examining the effects of job embeddedness and its trajectory on employee proactivity via an identification perspective.

Although job embeddedness has consistently been shown to be associated with positive workplace behaviors, our theoretical understanding of such associations remains far behind our empirical knowledge. In particular, it is unclear how job embeddedness goes beyond its common conceptualization as "stuckness" to motivate employees' discretionary, change-oriented behaviors at work. To this end, we trace the original theoretical foundation of job embeddedness theory in field theory and establish its theoretical connection to social identity theory. We propose that increased organizational identification is an intrinsic psychological mechanism through which job embeddedness motivates proactive behaviors from employees. Further informed by field theory, we also examine the implications of job embeddedness change over time. We propose that a more positive trajectory of embeddedness over time contributes to enhanced organizational identification and employee proactivity, above and beyond the absolute level of embeddedness. We report a longitudinal study that surveyed 264 employees at three points in time over the course of 1 year and provide substantial support for the hypotheses. Implications of our work are discussed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Design and properties of graded polyamide12/hydroxyapatite scaffolds based on primitive lattices using selective laser sintering.

Scaffolds with favorable biological characteristics and controlled functional gradient architectures are preferable for the repair of damaged tissues in bone tissue engineering. In this study, the triply periodic minimal surfaces (TPMS) were introduced to design functional gradient porous scaffolds based on Primitive lattices which were then manufactured by selective laser sintering (SLS) using pure polyamide12 (PA12) material and PA12/hydroxyapatite (HA) composite material. The mechanical properties and permeability of the scaffolds were then evaluated by mechanical compression experiments and computational fluid dynamics (CFD) analysis. The radial-graded scaffold was found to have superior good mechanical properties and permeability and be favorable for the subsequent growth of bone tissue. Further, the optimal PA12/HA composition was determined by analyzing the effect of the addition of HA particles on the hydrophilicity and mechanical properties of the composite scaffold. Additionally, the cytotoxicity tests were performed to evaluate the effects of PA12/HA gradient scaffold on cell growth. The obtained results demonstrate that the radial gradient scaffold with 15% HA addition exhibits a feasible combination of comprehensive performance and biological activity, indicating a great application potential in the field of bone tissue engineering.

Two-round quasi-whispering gallery mode exciton polaritons with large Rabi splitting in a GaN microrod.

We investigate the exciton polaritons and their corresponding optical modes in a hexagonal GaN microrod at room temperature. The dispersion curves are measured by the angle-resolved micro-photoluminescence spectrometer, and two types of exciton polaritons are identified with the help of the finite-difference time-domain simulation. By changing the pump position, the photon part of the exciton polaritons is found to switch between the quasi-whispering gallery modes and the two-round quasi-whispering gallery modes. The exciton polaritons formed by the latter are observed and distinguished for the first time, with a giant Rabi splitting as large as 2Ω = 230.3 meV.

Screening and identification of key biomarkers of papillary renal cell carcinoma by bioinformatic analysis.

BACKGROUND: Papillary renal cell carcinoma (PRCC) is the most common type of renal cell carcinoma after clear cell renal cell carcinoma (ccRCC). Its pathological classification is controversial, and its molecular mechanism is poorly understood. Therefore, the identification of key genes and their biological pathways is of great significance to elucidate the molecular mechanisms of PRCC occurrence and progression. METHODS: The PRCC-related datasets GSE7023, GSE48352 and GSE15641 were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified, and gene ontology (GO) term enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed. Cytoscape and STRING were used to construct the protein-protein interaction network (PPI) and perform module analysis to identify hub genes and key pathways. A heatmap of hub genes was constructed using the UCSC cancer genomics browser. Overall survival and recurrence-free survival of patients stratified by the expression levels of hub genes were analysed using Kaplan-Meier Plotter. The online database UALCAN was applied to analyse gene expression based on tissue type, stage, subtype and race. RESULTS: A total of 214 DEGs, specifically, 205 downregulated genes and 9 upregulated genes, were identified. The DEGs were mainly enriched in angiogenesis, kidney development, oxidation-reduction process, metabolic pathways, etc. The 17 hub genes identified were mainly enriched in the biological processes of angiogenesis, cell adhesion, platelet degranulation, and leukocyte transendothelial migration. Survival analysis showed that EGF, KDR, CXCL12, REN, PECAM1, CDH5, THY1, WT1, PLAU and DCN might be related to the carcinogenesis, metastasis or recurrence of PRCC. UALCAN analysis showed that low expression of PECAM1 and PLAU in PRCC tissues was related to stage, subtype and race. CONCLUSIONS: The DEGs and hub genes identified in the present study provide insight into the specific molecular mechanisms of PRCC occurrence and development and may be potential molecular markers and therapeutic targets for the accurate classification and efficient diagnosis and treatment of PRCC.

Spontaneous Activity in Primary Visual Cortex Relates to Visual Creativity.

Cognitive and neural processes underlying visual creativity have attracted substantial attention. The current research uses a critical time point analysis (CTPA) to examine how spontaneous activity in the primary visual area (PVA) is related to visual creativity. We acquired the functional magnetic resonance imaging (fMRI) data of 16 participants at the resting state and during performing a visual creative synthesis task. According to the CTPA, we then classified spontaneous activity in the PVA into critical time points (CTPs), which reflect the most useful and important functional meaning of the entire resting-state condition, and the remaining time points (RTPs). We constructed functional brain networks based on the brain activity at two different time points and then subsequently based on the brain activity at the task state in a separate manner. We explore the relationship between resting-state and task-fMRI (T-fMRI) functional brain networks. Our results found that: (1) the pattern of spontaneous activity in the PVA may associate with mental imagery, which plays an important role in visual creativity; (2) in comparison with the RTPs-based brain network, the CTP-network showed an increase in global efficiency and a decrease in local efficiency; (3) the regional integrated properties of the CTP-network could predict the integrated properties of the creative-network while the RTP-network could not. Thus, our findings indicated that spontaneous activity in the PVA at CTPs was associated with a visual creative task-evoked brain response. Our findings may provide an insight into how the visual cortex is related to visual creativity.

Flexible reconfiguration of functional brain networks as a potential neural mechanism of creativity.

Creativity relies on the reorganizing of multimodal information and flexible switching between different modes of thinking, suggesting an association between creativity and the reconfiguration of functional brain networks. Here, we investigated global and regional brain dynamics in high-creative (HCG, N = 22) and a low-creative (LCG, N = 20) groups during a divergent creative thinking task. We found that during the creative thinking task, the HCG demonstrated higher global network flexibility, as compared to the LCG. In addition, creative thinking in the HCG was associated with significantly higher regional flexibility in the medial superior temporal gyrus, superior parietal lobule, precuneus, nucleus accumbens, and the ventral inferior frontal gyrus. Interestingly, the LCG demonstrated decreased regional flexibility in the medial superior temporal gyrus, superior parietal lobule, and the ventral inferior frontal gyrus. We also found that the changes in global and regional flexibility in the creative compared with the control tasks were good features allowing for distinguishing between the HCG and the LCG. Taken together, these findings provide evidence that divergent creative thinking is associated with flexible reconfiguration of brain networks involved in verbal, working memory, and reward processing.

Mechanical properties of graded scaffolds developed by curve interference coupled with selective laser sintering.

In bone tissue engineering, a scaffold requires not only facilitating cell activity but also providing adequate mechanical support. One feasible approach to ensure it is to use modeling tools to design such a scaffold which is then built by additive manufacturing. In this study, curve interference was introduced to design porous scaffolds with gradient structures based on three lattice units (cubical, circular and spherical) which were then manufactured by selective laser sintering (SLS) with PA12/HA material. The mechanical properties of both uniform and graded porous scaffolds were analyzed based on numerical and experimental tests. The results show that the uniform cubical-pore scaffold as well as the gradient spherical-pore scaffold has the optimal mechanical property. Further, uniform and graded scaffolds exhibit distinct failure mechanism. The graded scaffold has a layer-by-layer failure feature while each layer of the uniform structure almost has the same degree of deformation. Additionally, the comparison between the numerical and experimental results shows a good agreement, validating that the proposed curve interference method coupled with SLS technology is suitable for implementing the design of scaffolds following expected performance.