Unique Positive Almost Periodic Solution for Discrete Nonlinear Delay Survival Red Blood Cells Model

We obtain sufficient conditions which guarantee the global attractivity of solutions for nonlinear delay survival red blood cells model. Then, some criteria are established for the existence, uniqueness and global attractivity of positive almost periodic solutions of the almost periodic system

Mater. Des.

Aluminum matrix composites reinforced with diamond particles were consolidated by spark plasma sintering. Metalloid silicon was added (Al-Si/diamond composites) to investigate the effect. Silicon addition promotes the formation of molten metal during the sintering to facilitate the densification and enhance the interfacial bonding. Meanwhile, the alloying metal matrix precipitates the eutectic-Si on the diamond surfaces acting as the transitional part to protect the improved interface during the cooling stage. The improved interface and precipitating eutectic-Si phase are mutually responsible for the optimized properties of the composites. In this study, for the Al-Si/diamond composite with 55 vol.% diamonds of 75 mu m diameter, the thermal conductivity increased from 200 to 412 Wm(-1) K-1, and the coefficient of thermal expansion (CTE) decreased from 8.9 to 7.3 x 10(-6) K-1, compared to the Al/diamond composites. Accordingly, the residual plastic strain was 0.10 x 10(-3) during the first cycle and rapidly became negligible during the second. Additionally, the measured CTE of the Al-Si/diamond composites was more conform to the Schapery's model. (C) 2014 Elsevier Ltd. All rights reserved.Aluminum matrix composites reinforced with diamond particles were consolidated by spark plasma sintering. Metalloid silicon was added (Al-Si/diamond composites) to investigate the effect. Silicon addition promotes the formation of molten metal during the sintering to facilitate the densification and enhance the interfacial bonding. Meanwhile, the alloying metal matrix precipitates the eutectic-Si on the diamond surfaces acting as the transitional part to protect the improved interface during the cooling stage. The improved interface and precipitating eutectic-Si phase are mutually responsible for the optimized properties of the composites. In this study, for the Al-Si/diamond composite with 55 vol.% diamonds of 75 mu m diameter, the thermal conductivity increased from 200 to 412 Wm(-1) K-1, and the coefficient of thermal expansion (CTE) decreased from 8.9 to 7.3 x 10(-6) K-1, compared to the Al/diamond composites. Accordingly, the residual plastic strain was 0.10 x 10(-3) during the first cycle and rapidly became negligible during the second. Additionally, the measured CTE of the Al-Si/diamond composites was more conform to the Schapery's model. (C) 2014 Elsevier Ltd. All rights reserved

Effectiveness of digital educational game and game design in STEM learning: a meta-analytic review

Abstract Digital educational games exhibit substantial promise in advancing STEM education. Nevertheless, the empirical evidence on both the efficacy of digital game-based learning and its designs in STEM education is characterized by notable inconsistencies. Therefore, the current study aimed to investigate (1) the general effect of digital game-based STEM learning over STEM learning without digital game, and (2) the enhancement effect of added game-design elements against base game versions in STEM learning. Two meta-analyses were conducted in this study. Based on the 136 effect sizes extracted from 86 studies, the first meta-analysis revealed a medium to large general effect of digital game-based STEM learning over conventional STEM learning (g = 0.624, 95% CI [0.457, 0.790]). In addition, digital game-based STEM learning appeared to be differentially effective for different learning outcome, different types of game, and different subject. A total of 44 primary studies and 81 effect sizes were identified in the second meta-analysis. The results revealed a small to medium enhancement effect of added game-design elements over base game versions (g = 0.301, 95% CI [0.163, 0.438]). Furthermore, our results indicated that the game-design elements added for content learning were more effective than those added for gaming experience. Possible explanations for these findings, as well as the limitations and directions for future research were discussed

Sophocarpine Alleviates Injury-Induced Intima Hyperplasia of Carotid Arteries by Suppressing Inflammation in a Rat Model

Introduction: Balloon angioplasty is a commonly applied procedure for treating atherosclerotic vascular diseases. However, the maintenance of long-term lumen patency is relatively difficult due to the occurrence of restenosis. Previous research has shown that the occurrence of vascular wall inflammation is associated with higher rates of restenosis. Sophocarpine (SPC) can exert various therapeutic effects such as anti-oxidation, anti-inflammation, anti-tumor, antivirus and immune regulation. This study aimed to investigate whether SPC can alleviate intimal hyperplasia following balloon injury in a rat carotid artery model. Methods: Twenty Sprague–Dawley rats were randomly assigned to four groups: (i) control, (ii) balloon injury, (iii) balloon injury followed by saline injection, and (iv) balloon injury followed by SPC administration. Each group contained five rats. A high-pressure balloon of 3 mm × 20 mm was placed in the carotid artery. The balloon was inflated to a pressure of 8 atmospheres to carry out rat carotid artery balloon injury model. The areas of neointimal and media were determined by Verhoeff_Van Gieson staining, and the intima-to-media (I:M) ratios were subsequently evaluated. After that, the protein levels of IL-6, IL-1β, MCP-1, NF-κB, TNF-α, VCAM-1, ICAM-1 and eNOS were measured. Results: The ratio of I:M was remarkably higher in the balloon injury group than in the control group (p < 0.01). SPC could significantly decrease the ratio of I:M compared with the balloon injury group (p < 0.01). Besides, the protein levels of IL-6, IL-1β, MCP-1, NF-κB, TNF-α, ICAM-1 and VCAM-1 were increased in rat carotid arteries exposed to balloon injury (p < 0.01), and treatment with SPC could attenuate these effects (p < 0.05). Furthermore, balloon injury inhibited the protein expression of eNOS (p < 0.01), and SPC could elevate its level (p < 0.05). Conclusions: SPC could alleviate an intimal hyperplasia in balloon-injured carotid artery, and the mechanisms underlying this protective effect might be due to its inhibitory potency against inflammation signals. Our study also implies the potential applicability of SPC in treating restenosis after balloon angioplasty

Effect of bolt tightening torque on fatigue life of multi-bolted composite structure

Bolt tightening torque has an influence on the fatigue life of the multi-bolted joints which cannot be ignored, but there are few methods to predict the fatigue life of the multi-bolted composite structure by considering the bolt tightening torque. A fatigue life prediction method of the multi-bolted composite structure by considering the bolt tightening torque is proposed. It can take into account the various damages of bolts and laminates and accurately calculate fatigue life and damage evolution of multi-bolted composite structure. The multi-bolted composite structure being composed of T300/BMP-316 composite laminates and TC4 titanium alloy bolts is used to verify the present method. The logarithmic error between the predicted fatigue life and the experimental is 4.36%, and the failure mode is consistent with the experimental. Through the present method, the influence of the bolt tightening torque is explored, in which it is found that with the increasing of bolt tightening torque, the fatigue life increases firstly and decreases, and there is an optimal tightening torque. By observing the damage evolution diagram, it is found that when the tightening torque is below the optimal tightening torque, the damage propagation cannot be effectively restrained, which will lead to the reduction of fatigue life. On the contrary, when the tightening torque is more than the optimal tightening torque, it will cause the initial damage to the test piece, which will also lead to the reduction of fatigue life. In engineering, to choose the best tightening torque of the structure for assembly can effectively improve the fatigue life of the structure

Integrative pan-cancer analysis of cuproplasia-associated genes for the genomic and clinical characterization of 33 tumors

Abstract. Background:. The molecular mechanisms driving tumorigenesis have continually been the focus of researchers. Cuproplasia is defined as copper-dependent cell growth and proliferation, including its primary and secondary roles in tumor formation and proliferation through signaling pathways. In this study, we analyzed the differences in the expression of cuproplasia-associated genes (CAGs) in pan-cancerous tissues and investigated their role in immune-regulation and tumor prognostication. Methods:. Raw data from 11,057 cancer samples were acquired from multiple databases. Pan-cancer analysis was conducted to analyze the CAG expression, single-nucleotide variants, copy number variants, methylation signatures, and genomic signatures of micro RNA (miRNA)–messenger RNA (mRNA) interactions. The Genomics of Drug Sensitivity in Cancer and the Cancer Therapeutics Response Portal databases were used to evaluate drug sensitivity and resistance against CAGs. Using single-sample Gene Set Enrichment Analysis (ssGSEA) and Immune Cell Abundance Identifier database, immune cell infiltration was analyzed with the ssGSEA score as the standard. Results:. Aberrantly expressed CAGs were found in multiple cancers. The frequency of single-nucleotide variations in CAGs ranged from 1% to 54% among different cancers. Furthermore, the correlation between CAG expression in the tumor microenvironment and immune cell infiltration varied among different cancers. ATP7A and ATP7B were negatively correlated with macrophages in 16 tumors including breast invasive carcinoma and esophageal carcinoma, while the converse was true for MT1A and MT2A. In addition, we established cuproplasia scores and demonstrated their strong correlation with patient prognosis, immunotherapy responsiveness, and disease progression (P <0.05). Finally, we identified potential candidate drugs by matching gene targets with existing drugs. Conclusions:. This study reports the genomic characterization and clinical features of CAGs in pan-cancers. It helps clarify the relationship between CAGs and tumorigenesis, and may be helpful in the development of biomarkers and new therapeutic agents