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The flexible and cost-effective service provided by cloud computing has led to the development of a vast array of applications in smart cities. Nevertheless, their traditional security approaches presented the concept of a static target for attacks, leading to an asymmetric situation between defenders and attackers. Adaptive cyber defense (ACD) has, therefore, recently emerged as a game-changer to reverse this asymmetry by reconfiguring the system according to the network scenario. Analyzing and quantifying the effectiveness of these ACDs are of high importance. Previous research on ACD analysis focused more on either studying the system properties using experiment-based approaches or on evaluating its effectiveness by different mathematical modeling approaches. However, little effort has been made to overcome the problems of isolated solutions. In this paper, we described the defensive process as a racing game between the attacker and the defender. On this basis, we conducted a thorough ACD effectiveness evaluation and suggested a comparison strategy using three methods, namely semi-Markov, stochastic reward net, and experimental methods. The obtained simulation results were approximate, and the error rate was less than 3.36% reflecting the reliability of the proposed methods. Based on the assessments, we finally summarized the features of these methods to specify and deduce different scenarios and their corresponding suitable evaluation method. [ABSTRACT FROM AUTHOR]

The crucial role of macrophages in the healing of chronic diabetic wounds is widely known, but previous in vitro classification and marker genes of macrophages may not be fully applicable to cells in the microenvironment of chronic wounds. The heterogeneity of macrophages was studied and classified at the single-cell level in a chronic wound model. We performed single-cell sequencing of CD45 + immune cells within the wound edge and obtained 17 clusters of cells, including 4 clusters of macrophages. One of these clusters is a previously undescribed population of macrophages possessing osteoclast gene expression, for which analysis of differential genes revealed possible functions. We also analysed the differences in gene expression between groups of macrophages in the control and diabetic wound groups at different sampling times. We described the differentiation profile of mononuclear macrophages, which has provided an important reference for the study of immune-related mechanisms in diabetic chronic wounds. [ABSTRACT FROM AUTHOR]

The mechanical behavior of Mn18Cr18N steel along different loading paths was investigated at room temperature. In compression–tensile loading paths, the strain hardening behavior depends on subsequent tensile loading directions. When the subsequent loading axis coincides with the previous loading axis, the strain hardening path coincides with the strain hardening path in previous strain stage. When the subsequent loading axis changed, the subsequent strain hardening rate is remarkable greater than that in the previous strain hardening stage. The tensile ductility is different along different loading paths. In consecutive compression–tensile loading paths, the tensile ductility increased first and then decreased. Dislocation rearrangement caused good ductility during the tensile loading. In non-consecutive compression–tensile loading paths, the tensile ductility decreased gradually. Dislocation multiplication occurred rapidly during the subsequent tensile loading. Stress hardening is remarkable during compression–tensile consecutive cyclic loading when the strain amplitude is greater than 0.01. The maximum tensile stress can be reached up to 1549.6 MPa at 3 cycles with 0.15 strain amplitude, which is an increase of 395.4 MPa compared to the simple tensile loading. During complex loading paths, dislocation configurations and the substructures not only depend on the accumulated strains but also on the loading paths. [ABSTRACT FROM AUTHOR]

The experimental study of Bauschinger effect in Mn18Cr18N austenitic stainless steel was presented by compression-tensile cyclic loading tests with the prestrains ranging from 0.005 to 0.1, which was illustrated utilizing stress-strain curves and analysed by TEM images from aspects of microstructural mechanisms. Moreover, the Bauschinger effect and its associated roundness phenomenon in reverse flow curve with respect to different cycles and cyclic strain amplitudes were evaluated in a quantitative manner. The experimental results indicate that Bauschinger effect is apparent during the test. At smaller cyclic strain amplitude, intergranular backstress is the main source of Bauschinger effect. With further increasing of cycles, dislocation density increases and dislocation movement is hindered in the reverse deformation. Therefore, Bauschinger effect is weakened to some extent. At large cyclic strain amplitude, backstress originating from the dislocation pile-up at grain boundaries and the continuous formation of deformation twins dominate the Bauschinger effect. In addition, the backstress results in the roundness of reverse curve during cyclic loading. The larger value of Δεp*, the more obvious the roundness of the reverse curve, and the more significant the Bauschinger effect. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) often causes delayed wound healing in patients, which can lead to limb loss, disability, and even death. Many conventional therapeutic strategies have been proposed, but there is still no effective therapy for DM wounds. This study aimed to explore the effects of CD271 and phosphorylated tyrosine kinase receptor A (pTrkA) on the migration and proliferation abilities of epidermal stem cells (eSCs) and on the activation of DM wound healing. We investigated the interventional effects of CD271-overexpressing eSC (CD271 eSC) treatment and pTrkA inhibition (through k252a treatment) on delayed wound healing using mice with streptozotocin-induced DM. The migration and proliferation abilities of control eSCs, CD271 eSCs, and k252a-treated CD271 eSCs were observed under high-glucose conditions. Decreases in CD271 and increases in pTrkA were observed in DM mouse skin compared with control mouse skin; in addition, the rate of wound closure in DM mice was promoted by CD271 eSC treatment but delayed by pTrkA inhibition. Furthermore, the CD271 eSC migration and proliferation were greater than of control eSCs. Compared with that of CD271 eSCs, the number of CD271+k252a eSCs decreased significantly under high-glucose conditions. In parallel, the expression levels of the pERK, pAkt, and pJNK pathways increased in CD271 eSCs and decreased in CD271+k252a eSCs under high glucose. Our findings demonstrate that CD271 and pTrkA affect DM wound closure by promoting the eSC migration and proliferation. This mechanism involving the pERK, pAkt, and pJNK pathways might be a new therapeutic target for the treatment of delayed wound re-epithelialization in DM. [ABSTRACT FROM AUTHOR]

C/Cu composite was prepared by vacuum melting infiltration. Ti and Cr were doped to the Cu alloy to improve the wettability between Cu and carbon. The microstructure was investigated by XRD, SEM and EDS. The arc erosion rate of Cf/Cu composite was investigated in vacuum. The results showed that the Ti and Cr could improve the wettability between Cu and C/C preform and the infiltration ability of Cu into C/C preform greatly. A TiC interface formed between the fibers and matrix. The good bonding between the fiber and matrix guaranteed that part of the Cu matrix can still be bonded on the fibers even when the material was exposed to the plasma. Consequently, the carbon fibers were protected from the erosion. In comparison, Cu was completely consumed by the arc erosion. Hence, the graphite was eroded and presented a cauliflower-like morphology. Therefore, the prepared C/Cu had better ability to resist the arc erosion, compared with common Cu-C material. [ABSTRACT FROM AUTHOR]

Taking Chinese pine in Qianshan Mountains as a sample, the tree ring width chronology including Standard, Residual, and Arstan chronologies was established. The results show that the tree ring width of Chinese pine is highly correlated with the temperatures from May to July and from September to November. Statistically significant positive correlations were observed between tree ring width and the extreme minimum temperatures in July and mean minimum temperatures in September. The chronology was significantly or very significantly correlated with extreme minimum temperatures in December and the following January, with mean minimum temperatures in January, with annual precipitation and with precipitation in April, May and the following December. The Chinese pine responded strongly to the monthly/yearly water vapor pressure and relative humidity. Annual and largely monthly evaporation in April–July had a negative effect on tree growth, and was particularly striking for evaporation in April–July. The narrow tree rings recorded by the chronology demonstrated the 30 occasions of extreme drought since 1800. The growth of Chinese pine in the Qianshan mountains were also affected by climate changes on a hemispheric and global scale. There were 11-, 23-and 50-year-common periodicities between the chronology and solar activity and 10-, 20-and 45-year-common periodicities between the chronology and geomagnetic activity. [ABSTRACT FROM AUTHOR]