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• Four ceramic-metal hybrid structures were fabricated and researched. • Influences of ceramic size, boundary constraints and connection mode of the substructures were researched. • Effects of constraints on the influences of penetration position on the performance were studied. • Hybrid structure exhibit much better performance than TC4 plate of equal areal density. Ceramic-metal hybrid structures have drawn extensive attentions as a protective structure for their excellent protection performances to defend penetration. In the present investigation, four hybrid structures were experimentally and numerically studied to determine the influences of the constraints on ceramic on their anti-penetration performances. It was found that the penetration resistances of the hybrid structures were significantly affected by the size of ceramic, boundary constraint and connection mode of the substructures. Both suitable boundary condition and appropriate connection mode of the substructures could provide relatively strong constraints to the ceramic prisms to improve the performance, yet the connection mode of substructures affected the performance more significantly. However, the penetration resistance of the structure with ceramic tile was slightly affected by the boundary condition and connection mode of the substructures. In addition, all of four hybrid structures exhibited much better anti-penetration performances than that of monolithic TC4 plate with the equal areal density. The better performances of the hybrid structures with monolithic frame suggest that suitable frames can provide strong constraints on ceramic prisms, and thus can be potentially used to defend penetrations. [ABSTRACT FROM AUTHOR]

The dynamic responses of metal rings subjected to high strain-rate loading are important issues in the design of munitions and armaments. However, limited work has been conducted to investigate the fragmentation behavior and fragment size characteristics of metal rings subjected to internal explosive loading of a hollow charge. In the present work, specimens with different thicknesses of metal rings and different radii of hollow cores were experimentally and numerically tested. It was found that, during the expansion of metal rings, some slightly deformed grains formed near the inner surface. These deformed grains made the inner surface of the fragments step-like, and were precursors to rupture. Large and small voids could initiate within some relatively thick rings during the expansion of the rings, and some cracks initiated from these voids and propagated towards the outer surface and inner surface. The circumferential rupture strain decreased dramatically as the radius of the cylindrical hollow core increased. For the specimens with the same hollow-charge, the circumferential rupture strain decreased as the thickness of the metal rings increased. In addition, it was easier to form strain localizations at the inner surface when the specimen had a larger height of the metal rings, resulting in a smaller circumferential width of the fragments for the specimen with a larger height of metal rings. Based on the fragment size characteristics, a modified formula was established and validated experimentally and numerically. The results indicate that the proposed formula is accurate and reliable in predicting the average circumferential width of the fragments from metal rings subjected to internal explosive loading of a hollow charge. • Fragmentation characteristics of metal rings filled with hollow-charge were studied. • Fragment size characteristics of metal rings filled with hollow-charge were studied. • A formula was proposed to predict the average circumferential width of the fragments. • The formula showed good agreement with the experimental and numerical results. [ABSTRACT FROM AUTHOR]

The impact response of a composite structure consisting of a metal-packaged ceramic interlayer and an ultra-high molecular weight polyethylene (UHMWPE) laminate has been studied through a ballistic test and numerical simulation. The studied structure exhibits 50% higher anti-penetration performance than the traditional ceramic/metal structure with the same areal density. The metal-packaged ceramic interlayer and the UHMWPE laminate are key components in resisting the penetration. By using a metal frame to impose three-dimensional constraints on ceramic tiles, the metal-packaged ceramic interlayer can limit the crushing of the ceramic and contain the broken ceramic fragment to improve the erosion of the projectile. The large deformation of UHMWPE laminate absorbs a large amount of energy from the projectile. By decreasing the amplitude of the shock wave and changing the distribution of the impact load in the structure, the projectile has longer residence time on the interlayer. The anti-penetration performance shows within 10% variation when the impact position is varied. Due to the asymmetric deformation and high elastic recovery ability of the UHMWPE laminate, the projectile trajectory deflection is increased, and the broken ceramic fragments are restrained, thereby mitigating after-effect damage caused by the projectile after penetrating the structure. [ABSTRACT FROM AUTHOR]

Purpose: Asprosin is a newly discovered adipose factor secreted by white fat, which is involved in glucose metabolism and inflammation. Neuregulin-4 (Nrg-4) is a new adipose factor released from brown adipose tissue and is considered to play an important role in metabolism. This study aims to explore the association between serum Asprosin, Nrg-4 level and coronary heart disease(CHD) in patients with type 2 diabetes mellitus(T2DM) and the diagnostic value. Patients and methods: 157 patients with T2DM were enrolled from Affiliated Hospital of Chengde Medical University between December 2020 to July 2021. These patients were divided into T2DM without CHD group (T2DM-0, n = 80) and T2DM with CHD (T2DM-CHD, n = 77). Serum Asprosin and Nrg-4 expression was detected by enzyme-linked immunosorbent assay, and the correlations between Asprosin or Nrg-4 and clinical and biochemical indicators were analyzed. A receiver operating characteristics curve analysis and area under the curve (AUC) were used to evaluate diagnostic accuracy. Results: Serum Asprosin level of the T2DM-CHD group were significantly higher and Nrg-4 level significantly lower than those of the T2DM-0 group.Spearman correlation analysis showed that serum Asprosin levels were significantly positively correlated with diabetes course,history of hypertension, fasting plasma glucose(FPG), glycosylated hemoglobin A1c(HbA1C), triglycerides(TG),triglyceride glucose index(TyG index) and urea, and negatively correlated with ALT (all p < 0.05). Nrg-4 was negatively correlated with history of hypertension, body mass index(BMI), FPG, HbA1C, TG, and TyG indexes (all p < 0.05), and positively correlated with high-density lipoprotein cholesterol(HDL-C)(p < 0.05).Logistic regression analysis showed that after adjusting potential confounders, Asprosin was a risk factor for diabetes mellitus, Nrg-4 was a protective factor.The AUC of Asprosin for diagnosing T2DM-CHD was 0.671 (95% confidence interval [CI] 0.584–0.759), and the AUC of the Nrg4 index for diagnosing T2DM-CHD was 0.772 (95% CI 0.700-0.844). The AUC of Asprosin and Nrg-4 for the combined diagnosis of T2DM-CHD was 0.796 (95% CI 0.726–0.864). Conclusion: Asprosin and Nrg-4 may be novel diagnostic biomarkers for T2DM with CHD, as they effectively improved the diagnostic accuracy for T2DM-CHD. [ABSTRACT FROM AUTHOR]

• A novel fragment warhead with double casings sandwiched charge is proposed. • The different fragment velocities of each casing were measured by flash-radiography. • A formula was established to predict the fragment velocities of each casing. • The formula shows good agreement with the experimental and numerical results. • The fragment velocities of casing are affected by the size of the charge and casing. This work introduces a novel fragmentation warhead that can produce two groups of fragments with different velocity characteristics and strike the target sequentially. The two groups of fragments come from two separate casings in one warhead, and the different velocities of fragments from different groups are attained by having a charge compartment sandwiched between the two casings in the warhead. A theoretical analysis formula is established to predict the maximum velocity of fragment from each casing based on energy balance. The results of X-ray radiography experiment and 3D smooth-particle hydrodynamics numerical simulation indicate that the proposed formula is accurate and reliable in calculating the fragment velocity as long as the thickness of the inner casing is less than 30% the radius of the inner charge. The fragment velocities of warheads with different structure are further analyzed, and the results show that the fragments of the two casing exhibit greater disparity in their maximum velocity when more charge is packed in the sandwiched compartment instead of enclosed in the inner casing. [ABSTRACT FROM AUTHOR]

Abstract Ceramic-metal hybrid structures have attracted significant attentions as protection structures because of their high anti-penetration performance. In the present study, a ceramic-metal hybrid structure was constructed with a TC4 frame and ceramic prisms, and its anti-penetration performance and mechanism against a vertical steel projectile were investigated experimentally and numerically. The hybrid structure exhibited much higher penetration resistance than the TC4 monolithic plate of equal areal density. It was found that the high anti-penetration performance was mainly attributed to the frame in the structure, which confined the ceramic prisms and effectively improved their penetration resistance. Additional performance improvement was found to derive from the adhesive that bound the ceramic prisms with the frame. The TC4 frame and adhesive prolonged the dwell time of the projectile on the ceramic prisms and significantly dissipated the projectile kinetic energy. In addition, although the hybrid structure in this investigation was heterogeneous, its anti-penetration performance was affected less by the impact position than those of conventional hybrid structures. [ABSTRACT FROM AUTHOR]

In this study, we aimed to determine whether liraglutide could effectively reduce insulin resistance (IR) by regulating Sestrin2 (SESN2) expression in L6 rat skeletal muscle cells by examining its interactions with SESN2, autophagy, and IR. L6 cells were incubated with liraglutide (10–1000 nM) in the presence of palmitate (PA; 0.6 mM), and cell viability was detected using the cell counting kit-8 (CCK-8) assay. IR-related and autophagy-related proteins were detected using western blotting, and IR and autophagy-related genes were analyzed using quantitative real-time polymerase chain reaction. Silencing SESN2 was used to inhibit the activities of SESN2. A reduction in insulin-stimulated glucose uptake was observed in PA-treated L6 cells, confirming IR. Meanwhile, PA decreased the levels of GLUT4 and phosphorylation of Akt and affected SESN2 expression. Further investigation revealed that autophagic activity decreased following PA treatment, but that liraglutide reversed this PA-induced reduction in autophagic activity. Additionally, silencing SESN2 inhibited the ability of liraglutide to up-regulate the expression of IR-related proteins and activate autophagy signals. In summary, the data showed that liraglutide improved PA-induced IR in L6 myotubes by increasing autophagy mediated by SESN2. [ABSTRACT FROM AUTHOR]

The gut microbiota plays an important role in the regulation of the immune system and the metabolism of the host. The aim of the present study was to characterize the gut microbiota of patients with type 2 diabetes mellitus (T2DM). A total of 118 participants with newly diagnosed T2DM and 89 control subjects were recruited in the present study; six clinical parameters were collected and the quantity of 10 different types of bacteria was assessed in the fecal samples using quantitative PCR. Taking into consideration the six clinical variables and the quantity of the 10 different bacteria, 3 predictive models were established in the training set and test set, and evaluated using a confusion matrix, area under the receiver operating characteristic curve (AUC) values, sensitivity (recall), specificity, accuracy, positive predictive value and negative predictive value (npv). The abundance of Bacteroides, Eubacterium rectale and Roseburia inulinivorans was significantly lower in the T2DM group compared with the control group. However, the abundance of Enterococcus was significantly higher in the T2DM group compared with the control group. In addition, Faecalibacterium prausnitzii, Enterococcus and Roseburia inulinivorans were significantly associated with sex status while Bacteroides, Bifidobacterium, Enterococcus and Roseburia inulinivorans were significantly associated with older age. In the training set, among the three models, support vector machine (SVM) and XGboost models obtained AUC values of 0.72 and 0.70, respectively. In the test set, only SVM obtained an AUC value of 0.77, and the precision and specificity were both above 0.77, whereas the accuracy, recall and npv were above 0.60. Furthermore, Bifidobacterium, age and Roseburia inulinivorans played pivotal roles in the model. In conclusion, the SVM model exhibited the highest overall predictive power, thus the combined use of machine learning tools with gut microbiome profiling may be a promising approach for improving early prediction of T2DM in the near feature. [ABSTRACT FROM AUTHOR]