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The large-size AZ80 magnesium alloy slab was manufactured using direct chill casting assisted by out-of-phase pulsed magnetic field. Subsequently, the effects of OPMF on the as-cast structure and the Al content were investigated. By using numerical simulation, the macro physical fields including the flow field, the temperature distribution, and the sump profile were simulated and compared between the slab with and without OPMF. After introducing the OPMF, significant grain refinement occurred, and the macrosegregation degree of the Al element was alleviated. Compared with the case without OPMF, the simulations revealed that the melt flow rate and its range were greatly increased, accelerating the convective heat transfer in the sump. As a result, the temperature field was more uniformed distributed, the cooling rate was increased and the sump depth became shallower. The relevant mechanisms between the experimental results and the simulation results were discussed in detail.

BackgroundAneurysmal subarachnoid hemorrhage (aSAH) is a life-threatening medical condition with a high fatality and morbidity rate. There was a substantial link between the modified Fisher grade of aSAH and the neurological function deficit. This study aimed to analyze the factors associated with the modified Fisher grade of aSAH using a machine learning approach.MethodsA multi-center observational study was conducted. The patients with aSAH were recruited from five tertiary hospitals in China. The volume of hemorrhage in aSAH was measured using the modified Fisher grade scale. The risk factors responsible for the modified Fisher grade of aSAH were analyzed, which include sociodemographic factors, clinical factors, blood index, and ruptured aneurysm characteristics. We built several tree-based machine learning models (XGBoost, CatBoost, LightGBM) for prediction and used grid search to optimize model parameters. To comprehensively evaluate the model, we used Accuracy, Precision, Area Under the Receiver Operating Characteristic Curve (AUROC), Area Under the Precision-Recall Curve (AUPRC), and Brier as evaluation indicators to assess the model performance and select the best model.ResultsA total of 888 patients with aSAH were recruited, of whom 305 with modified Fisher grade of 3 and 4. The results show that the XGBoost model has the highest AUROC of 0.772, and the indicators are better than CatBoost and LightGBM. The feature importance graph shows that the top feature variables include platelet, thrombin time, fibrinogen, preadmission systolic blood pressure, activated partial thromboplastin time, and the time interval between the onset of aSAH and the first-time CT examination.ConclusionThe factors responsible for the modified Fisher grade of aSAH were identified, which offered valuable insights for future research and clinical intervention. These risk factors should be controlled in the treatment of unruptured aneurysms, and appropriate treatment can be given if necessary to reduce the risk of severe hemorrhage after aneurysm rupture.

Understanding the evolution of Fe–containing intermetallic compounds (Fe–IMCs) in Al–Si–Mg alloys is essential for improving the mechanical performances. This paper aims to systemically evaluate the influences of both the single addition of Mn or Mo, and the combined additions of Mn and Mo on the evolution of Fe–IMCs and mechanical performances of Al–Si–Mg cast alloys. Results reveal that the as–cast microstructures of these alloys are primarily composed of Al3M (M means Ti, Zr, or TiZr), α–Al, eutectic Si, Mg2Si, Q–Al5Cu2Mg8Si6, and some irregular Fe–IMCs. It is clear that the morphology and size of Fe–IMCs are significantly affected by the single or combined addition of Mn and Mo. Moderate Mn content facilitates the formation of Chinese script–like α–Al(FeMn)Si phases that are favorable to the mechanical properties. The combined addition of Mn and Mo refines the α–Al(FeMn)Si phases and promotes the formation of Chinese script–like α–Al(FeMnMo)Si phases. Furthermore, as the Mo level increases, β–AlFeSi, π–Al8FeMg3Si6, and α–Al(FeMn)Si disappear successively, which also helps improve the mechanical performances. In this article, maximum hardness, ultimate tensile strength, yield strength and elongation of 87.04 HV, 275.34 MPa, 139.70 MPa, 7.88% are obtained when Fe, Mn and Mo are added at 0.20wt.%, 0.02wt.%, and 0.27wt.%, respectively. The purpose of this work is to provide an efficient method to minimize or even eliminate the adverse effects of Fe–IMCs and thus improve the mechanical performances of Al–Si–Mg cast alloys.

Unlike the rod-like T–Al20Cu2Mn3 dispersoids, the spherical Al7(Cr, Mn) and Al6(Fe, Mn, Mo) precipitated in Al–Cu–Mg–Ag–Mn alloys with CrxMo(0.2-x) addition, retained the deformed substructure, and acted as a dispersion reinforcement. In this study, the precipitation behavior of dispersoids in Al–Cu–Mg–Ag–Mn alloys with various CrxMo(0.2-x) (x = 0.15, 0.10, 0.05 wt.%) at 400 °C/12 h + 515 °C/24 h homogenization was investigated. The compositional and structural evolution of dispersoids in Al–Cu–Mg–Ag–Mn alloys were investigated by optical microscopy and atomic resolution high-angle annular dark-field scanning transmission electron microscopy. The effects of CrxMo(0.2-x) addition on morphology, size and number density of dispersoids inhibited the recrystallization behavior and improved the mechanical properties of alloys in varying degrees. When x = 0.15 in CrxMo(0.2-x), the large amount of Al7(Cr, Mn) precipitates to refine the T–Al20Cu2Mn3, and dispersoid-free zones (DFZ) significantly decreases. As x decreases to 0.05, the homogeneous Al6(Fe, Mn, Mo) dispersoids present the opposite precipitation trend of T–Al20Cu2Mn3 to compensate for the DFZ. During the deformation and subsequent heat treatment, the Al–Cu–Mg–Ag–Mn alloy with Cr0.05Mo0.15 addition maintains the highest substructure and dislocation density owing to the highest number density of spherical dispersoids, demonstrating excellent mechanical properties at ambient and elevated temperatures.

The influence of low-frequency electromagnetic casting (LFEC) and Sc addition as variables on the microstructure, properties, and deformation behavior of 7A36 aluminum alloy has been systematically examined. The results have predicted that the LFEC could make the grains of the as-cast alloy finer by electromagnetic stirring and forced convection. By the addition of Sc, the average diameters of the equiaxed grains have been reduced and the intensity of the fiber texture has become weakened. The fine and continuous η′ precipitates on the grain boundaries (GBs) instead of the coarse large-sized discontinuous η′ precipitates, which results in a more uniform distribution of plastic deformation and which is beneficial for improving plasticity. By adding Sc and applying LFEC, the large size η′ internal grain precipitated phase decreased slightly. The fine nano-sized Al3(Sc, Zr) phase particles were dispersed in the matrix. As the dislocation movement had to travel less distance, that's why this process consumed less energy. These features also reduced the strain difference within the grain and near the grain boundary, which result in the increase of EL. The excellent mechanical properties of 7A36 aluminum as extruded plates were obtained when it was aged at 120 °C for 8 h by Sc micro-alloying and applying LFEC. The yield strength (YS) and ultimate tensile strength (UTS) remained at 738.3 MPa and 767.0 MPa, respectively, while the elongation (EL) to failure 6.5% is increased by 160% than the value of direct chill casting.

Abstract. Background:. Sirtuin-3 (Sirt3) has been documented to protect against mitochondrial dysfunction and apoptosis. Honokiol (HKL) is a Sirt3 pharmacological activator with reported neuroprotective effects in multiple neurological disorders. The present study aimed to explore the neuroprotective effects of HKL and the role of Sirt3 following intracerebral hemorrhage (ICH). Methods:. An in vivo ICH model in rats was established by injecting autologous blood into the right basal ganglia. PC12 cells were stimulated with hemin. For the in vivo investigation, the modified Neurological Severity Scores and the Morris water maze test were performed to assess neurological deficits. Hematoxylin–Eosin and Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining were employed to evaluate the histopathology and apoptosis. Immunohistochemical staining was used to investigate the expression of Sirt3. Adenosine triphosphate (ATP) levels were quantified to assess mitochondrial dysfunction. Cell counting kit-8, lactate dehydrogenase assay, and flow cytometry were used to analyze cell vitality and apoptosis in vitro. Immunofluorescence staining was performed to observe mitochondrial morphology and dynamin-related protein 1 (Drp1) localization to mitochondria. Western blot was applied to quantify the expression of Sirt3, Bax, Bcl-2, cleaved-caspase-3, Drp1, phosphorylation of Drp1 at serine-616, and phosphorylation of Drp1 at serine-637 in vivo and in vitro. Results:. HKL treatment alleviated neurological deficits, attenuated the histopathological damage and cell apoptosis, and restored the decreased ATP levels in ICH rats. HKL improved cell survival rate, reduced cell apoptosis, and inhibited mitochondrial fission in PC12 cells. Moreover, both in vivo and in vitro models showed increased phosphorylation of Drp1 at Ser616, and reduced phosphorylation of Drp1 at Ser637. Meanwhile, immunofluorescence co-localization analysis revealed that hemin increased the overlap of Drp1 and mitochondria in PC12 cells. The phosphorylation and mitochondrial translocation of Drp1 were effectively reversed by HKL treatment. Importantly, the selective Sirt3 inhibitor 3-(1H-1,2,3-triazol-4-yl) pyridine suppressed these effects. Conclusion:. Our findings demonstrated that HKL ameliorated ICH-induced apoptosis and mitochondrial fission by Sirt3, suggesting that HKL has immense prospects for the treatment of ICH.

The influence of extrusion temperature and speed on the microstructures and mechanical properties of the as-extruded Mg–6Zn–1Y–0.85Zr (ZWK610) alloy was inquired by indirect extrusion at three ram speeds (1, 3 and 6 mm/s) and extruding temperatures (250, 300 and 350 °C). The extruded alloy organization mainly consists of equiaxed finely dynamic recrystallized (DRXed) grains, elongated coarse un-DRXed grains and massive W–Mg3Y2Zn3 and I–Mg3Zn6Y phases. The increasing extrusion temperature and speed result in larger DRXed grains, higher DRXed volume fractions and fewer second phase volume fractions. Mechanical properties drop with increasing extrusion temperature and speed. The extruded alloy prepared at low temperature and speed reveals a lower DRXed volume fraction, a finer DRXed grain size and a higher phase volume fraction because a large number of depressively distributed particles could inhibit the grain boundary migration and pin the dislocations effectively. Excellent mechanical properties were acquired at 250 °C and 1 mm/s, with ultimate tensile and tensile yield strengths of 410 MPa and 365 MPa, respectively, while the elongation is 7.1%.

High-throughput double cone specimens were used to study the influence of Mo on the microstructure evolution of Al–Cu–Mg–Ag alloy under a wide range of strain along the axis. The microstructure evolution was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD). Results demonstrated that Al6(Fe, Mn, Mo) dispersoids formed in the Al–Cu–Mg–Ag alloy with the addition of 0.2% Mo during double-step homogenization. Meanwhile, rod-like Al20Cu2Mn3 and disk-like Al6(Fe, Mn, Mo) dispersoids segregated to opposite distribution in interdendritic regions and dendrite cores, respectively, which obviously eliminated the dispersoid-free zones and intragranular sparse regions. With different effective strains along the axis, Al6(Fe, Mn, Mo) dispersoids obviously reduced the transformation from Low-angle grain boundaries to High-angle grain boundaries. The nucleation and growth of dynamic recrystallization grains were effectively inhibited by the coupling of Al20Cu2Mn3 and Al6(Fe, Mn, Mo) dispersoids due to the obstruction of dislocation movement.

The biodegradable Mg–2Zn-1Gd-0.5Zr-xCu (x = 0, 0.1, 0.3, 0.5 wt.%) alloys are prepared to evaluate their microstructures, corrosion behavior, biocompatibility and antimicrobial properties. When the Cu element adds to the alloys, the new MgZnCu phase generates in the alloys in addition to the MgZn2 phase, W–Mg3Gd2Zn3 phase and I–Mg3Gd6Zn phase. With the Cu content increases, the grains become finer. Meanwhile, the shape of the MgZnCu phase transforms from spherical and elongated into the reticular. The grain boundary, the reticular W–Mg3Gd2Zn3 phase and the MgZnCu phase act as physical barriers to hinder the spread of corrosion. The generation of Ca–P compounds and the formation of dense oxides further improve the corrosion resistance of the alloys. Meanwhile, an increase in the content of the second phase and a change in the morphology of the MgZnCu phase also enhance galvanic corrosion, which reduces the corrosion resistance of the alloys. The corrosion rate of the Mg–2Zn-1Gd-0.5Zr-0.1Cu alloy is 0.47 ± 0.05 mm/year, and its degradation rate is much lower than that of the other Cu-containing alloys. Mg–2Zn-1Gd-0.5Zr-0.1Cu alloy has no cytotoxicity to MC3T3-E1 in the biocompatibility tests and shows good antibacterial properties in the antimicrobial experiments. In general, the Mg–2Zn-1Gd-0.5Zr-0.1Cu alloy is considered as the potential biodegradable antimicrobial biomaterial for bone implants.

Fine, uniform and equiaxed grain structure is one of the most striking features of high-quality Al targets. In general, the imposition of magnetic stirring on the liquid Al during the solidification process is an effective method to promote grain refinement. In the present study, a self–made rotating system of permanent magnets is reported to stir liquid Al during solidification. The temperature change and grain structure of pure Al subjected to a permanent magnet stirring (PMS) are analyzed. The experimental results reveal that the forced convection driven by PMS can lead to a more homogeneous temperature field in the melt. Meanwhile, PMS can greatly refine the grain structure of pure Al and eliminate cavities, but it may induce more gas holes in the ingots. Moreover, a fresh intermittent permanent magnet stirring (I-PMS) approach has been proposed and successfully applied to realize grain refinement of pure Al. Some casting problems can be perfectly solved using suitable processing parameters. Through some valuable experimental works, systematic researches on grain refinement of pure Al under PMS are performed to better understand its refining mechanisms. Therefore, this article further enhances our understanding of related fields and fills the research blank.

BackgroundOrexin-A (OXA) is a polypeptide produced in the hypothalamus, which binds to specific receptors and exerts multiple physiological effects. Autophagy plays a vital role in early brain injury (EBI) after intracerebral hemorrhage (ICH). However, the relationship between OXA and autophagy after ICH has not been confirmed.MethodsIn this study, the protective role of OXA was investigated in a model of hemin-induced injury in PC12 cells and blood-injection ICH model in rats, and its potential molecular mechanism was clarified. Neurobehavioral tests, brain water content, and pathologic morphology were assessed after ICH. Cell survival rate was determined using Cell Counting Kit-8 (CCK-8), while apoptosis was detected using flow cytometry. The autophagy protein LC3 that was originally identified as microtubule-associated protein 1 light 3 was evaluated by immunohistochemistry. The ultrastructural changes of cells following ICH were observed by transmission electron microscopy. Western blotting was performed to determine the expression levels of LC3, p62/SQSTM1 (p62), phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2), total extracellular signal-regulated kinase 1/2 (t-ERK1/2), mammalian target of rapamycin (mTOR), and phosphorylated mammalian target of rapamycin (p-mTOR).ResultsOXA treatment significantly improved neurofunctional outcomes, reduced brain edema, and alleviated neuronal apoptosis. OXA administration upregulated p-mTOR and p62, while it downregulated p-ERK1/2 and LC3; this effect was reversed by the orexin receptor 1 (OXR1) antagonist SB-334867.ConclusionsThis study demonstrates that OXA suppresses autophagy via the OXR1-mediated ERK/mTOR signaling pathway to exert neuroprotective effects, and it might provide a novel therapeutic approach in patients suffering from ICH.

Samples of pure titanium with a purity of 99.99 wt.% were successfully processed by equal channel angular pressing (ECAP) at cryogenic temperature. Deformed microstructures of ECAPed samples were characterized by electron backscattering diffraction (EBSD), and its homogeneity was studied by color-coded contour mapping of microhardness distribution. EBSD results indicate the original coarse grains with an average grain size of 196 μm were significantly refined to 0.56 μm after four passes, and that the prism slip systems were activated in the whole deformation process and with increasing passes number more slip systems were activated. The hardness mapping reveals that the microstructure of samples prior to ECAP is basically homogeneous but becomes inhomogeneous after one pass and then gradually homogeneous with additional passes. In addition, the grain refinement of ECAPed titanium at cryogenic temperature was discussed and confirmed by CDRX. Also, the factors of influence on the homogeneity of microstructure were analyzed.

A novel technology, termed intermittent permanent magnet stirring (I-PMS), is proposed to improve the quality of aluminum alloy ingots. In this paper, the melt flow and solidification structure of Al–4.5Cu alloy were investigated through I-PMS. The grain refinement mechanism of I-PMS is also discussed. The results indicate that the melt flow patterns and distributions can be greatly affected by I-PMS. When I-PMS is applied during solidification, the melt undergoes a series of complicated periodic three-dimensional flows. Compared without I-PMS, the solidification structure of Al–4.5Cu alloy with I-PMS was remarkably refined, and the optimum solidification structure could be realized utilizing appropriate processing parameters.

Under the condition of strain rates of 0.001–1 s−1 and temperatures of 473–723 K, the flow behaviors of the cast-homogenized ZK10 magnesium alloy were studied through the isothermal compression test with final true strain of 1. In view of this, the Arrhenius equation subject to strain was treated with a comprehensive correction, the deformation activation energy Q of ZK10 alloy was calculated to be 181.87 kJ/mol, and a reliable flow stress model of ZK10 alloy was established. Meanwhile, the processing maps and microstructure evolution of ZK10 alloy were analyzed, which indicated that obvious dynamic recrystallization occurred during thermal compression deformation of ZK10 alloy under the above process conditions. When ZK10 alloy was hot compressed at 473 K in the instability zone, serious instability deformation and macro cracks occurred at strain rates of 0.001 s−1 and 0.01 s−1. The optimum process parameter of ZK10 alloy under the experimental conditions was obtained to be 673 K/1 s−1, and the corresponding microstructure was the most uniform and finest, which provides useful guidance for the selection of process parameters of ZK10 alloy.

Abstract The elimination of intracranial hematomas has received widespread attention and the interactions between hemolytic agents and hematomas have become a hot research topic. In this study, we used the Navier-Stokes equation to describe the flow control equation for hemolytic agents in a tube and used Fick’s law and the Maxwell-Stefan diffusion theory to describe the diffusion and mass transfer of hemolytic agents and hematomas. The physical fields and initial boundary conditions were set according to the parametric properties of the fluid and drainage tube. The COMSOL Multiphysics software was used to simulate the streamline distribution of hemolytic agents in a bifurcated drainage tube. Additionally, the diffusion behaviors of the hemolytic agents into hematomas were simulated and visual analysis of coupled multiphysics was performed to realize the digitization and visualization of engineering fluid problems and contribute to the field of medical engineering.

For obtaining the finer grains of magnesium alloy, a novel combined pulsed magnetic field with different initial phases, also called out-of-phase pulsed magnetic field (OPPMF), was applied to study the solidification structure of AZ80 magnesium alloy. The numerical simulation was simultaneously conducted to investigate the refinement mechanisms. The experimental results showed that the macrostructure could be effectively refined by applying external magnetic field. Meanwhile, finer grains were obtained with the higher current intensity. However, the increase of current intensity could only refine the grains to about 0.5 mm. Furthermore, compared to a single pulsed magnetic field (PMF) and alternating series of OPPMF (Connection II), a finer structure was observed when the consecutive series of OPPMF (Connection I) was imposed. In contrast with a single PMF and Connection II, the numerical results showed that the greater axial Lorentz force was obtained under the Connection I, generating the stronger forced flow in the melt. It is believed that abundant nuclei could detach from the mold wall and move faster into the interior melt due to the stronger forced flow; besides, the lower superheat and greater temperature uniformity in bulk melt were realized, accounting for the finest structures under the Connection I.

Switching circuits provide an interesting strategy for modularization construction of digital computing. Multi-step reactions on DNA origami template are essentially the same as switching circuits. Herein, DNA switch circuits(DSCs) based on binary tree is used to solve arbitrary digital computing. The establishment and implementation of DSCs is completed on DNA origami template. The nodes in the binary tree are mapped to hairpins on DNA origami template and the switches are mapped to the hairpins which is abundant in the solution. DSCs operate on the basis of a hybridization chain reaction on DNA origami substrates. The results are read using bulk fluorescence spectroscopic methods. Compared with multi input logic “AND” gate, the number of DNA strands (anchored hairpins and fuels) required by DSCs is reduced more than 33.33% and 66.67%, respectively. The DSCs are used to construct the full-subtractor and prime number discriminator, which indicates this strategy can construct arbitrary digital circuits.

ObjectivesVarious stereotactic aspirations have been accepted; however, no standard stereotactic aspiration has been established for the treatment of spontaneous intracerebral hemorrhage (ICH). The authors explored an easy, fast, and effective procedure by using a new brain surgery head frame and location sticker for the removal of spontaneous hematoma.Patients and MethodsA retrospective database review was performed from January 2018 to March 2020 to identify patients with ICH who were treated with puncture and drainage for hematoma by using a new brain surgery head frame and location sticker for positioning and guidance.ResultsA total of 45 patients with spontaneous ICH were enrolled in our study. The mean (± SD) surgical time was 29.3 ± 4.1 min. The average hematoma evacuation rate was 72.2%. The mean (± SD) preoperative Glasgow Coma Scale (GCS) score was 9.58 ± 2.92; the mean GCS score increased to 11.55 ± 2.59 (p = 0.006) and 12.86 ± 2.04 (p < 0.001) at 1 week after surgery and at the time of discharge, respectively. The mean (± SD) preoperative muscle force score was 1.25 ± 1.51; the mean muscle force score had improved to 2.20 ± 1.64 (p = 0.009) and 2.88 ± 1.64 (p < 0.001) at 1 week after the operation and the time of discharge, respectively. Out of these, one patient experienced postoperative rebleeding, however, no further hematoma expansion was found after the second aspiration and thrombolysis.ConclusionUsing this brain surgery, head frame and location sticker combined with urokinase infusion appears simple, safe, and effective for the removal of hematoma for patients with spontaneous ICH. However, randomized controlled trials are necessary to provide more concrete evidence-based results.

The oxidation behaviors of AZ80, AZ80-0.32 Y and AZ80–0.38 Nd (wt.%) alloys were researched at 413 °C, 420 °C, 427 °C and 433 °C for up to 6 h in air environment via a high precision analytical balance, a laser confocal microscope, differential scanning calorimeter (DSC) analysis, X-ray diffraction (XRD) analysis, scanning electron microscope (SEM) observation, and X-ray photoelectron spectroscopy (XPS) analysis. The results show that the weight gain and oxidation rate of AZ80 are reduced significantly, the initiation form and propagation of cracks in oxide layer are changed. Compact and protective oxide layer forms on alloy surface with Y or Nd addition. And the activation energies of AZ80, AZ80-0.32Y and AZ80-0.38Nd alloys calculated via Arrhenius equation are 82.556 kJ/mol, 177.148 kJ/mol and 136.738 kJ/mol, respectively.

In situ Mg2Si particles often show coarse and irregular morphologies in Al–matrix composites, which results in inhomogeneous microstructures and poor mechanical properties. This leads to poor deformation ability in Mg2Si particles reinforced Al–matrix composites. Herein, a refined process exploiting refined Mg2Si particles was developed to enhance microstructure homogeneity after hot rolling in an Al-11.73%Mg-6.63%Si composite. The hot-rolled sheet reduces the macroscopic cracking on the edge when the Mg2Si particles of the as-cast microstructure are refined by the addition of phosphorus. The refined Mg2Si particles in the as-cast state shows further size reduction and exhibits homogeneous distribution by hot rolling (reduction of 76%). The microstructure also shows uniform deformation zones, subgrains and high-density dislocation regions via hot rolling. The homogeneous deformation microstructure results in needle-like, high-density precipitates after artificial aging and decreases the stress concentration of load bearing, which is beneficial to the tensile properties and wear resistance of the composite. The wear behavior of the composites improves with Mg2Si-particle refinement and microstructural homogeneity. Keywords: Hot rolling, T6 treatment, Mechanical properties, Wear behavior, Al–Mg2Si in situ composite

Abstract Based on patient computerized tomography data, we segmented a region containing an intracranial hematoma using the threshold method and reconstructed the 3D hematoma model. To improve the efficiency and accuracy of identifying puncture points, a point-cloud search arithmetic method for modified adaptive weighted particle swarm optimization is proposed and used for optimal external axis extraction. According to the characteristics of the multitube drainage tube and the clinical needs of puncture for intracranial hematoma removal, the proposed algorithm can provide an optimal route for a drainage tube for the hematoma, the precise position of the puncture point, and preoperative planning information, which have considerable instructional significance for clinicians.

The image encryption schemes combining chaotic maps, DNA coding, and DNA sequence operation can effectively protect the image. In this paper, a double-layer image encryption scheme is proposed by combining chaotic maps with DNA strand displacement (DSD). Chaotic maps are used to generate pseudorandom sequences and perform routine scrambling and diffusion operations on the plaintext image. We propose three DSD-based encryption rules according to the diversity of DNA strand displacement, and these three encryption rules are used to encrypt the image at the DNA sequence level. The plaintext image can be transformed into the cipher image, which is difficult to be recognized without the correct keys through the double-layer encryption at the level of chaotic maps and DNA. Simulation results and security analysis show that the proposed encryption scheme can effectively protect image information and resist conventional information attacks.

DNA logic gates are an important branch of DNA computing and have a wide range of applications in DNA computing. In this study, logic circuits of AND gate and NAND gate are built on origami substrate. The realization of AND gate uses polymerase strand displacement (PSD) reaction and hybridization chain reaction (HCR). If there is a fluorescent band “1” displayed, the result is true. The realization of the NAND gate requires a cyclic reaction. If there is a fluorescent band “A” or “T” displayed, the result is true; if no fluorescent band is displayed, the result is false.

The casting table with lubricating oil and wiper is applied simultaneously to produce super-high-strength 7055 aluminum alloy (Al7055) ingots, and 30 T Al7055 ingots with a diameter of 582 mm were cast successfully. In this study, the microstructure and macrosegregation of the ingots were investigated using an optical microscope (OM). The research results show that the hydrogen content in the liquid metal can be decreased from 0.198 mL/100 g Al to 0.103 mL/100 g Al when three rotors are used in the degassing tank. Compared with the conventional hot-top casting table, the surface quality can be improved by using the casting table with oil lubrication. The temperature gradient between the ingot center and edge can be decreased by using the wiper during the casting process from 320 °C to 150 °C, the cracking tendency caused by the ingot temperature gradient can be decreased, the segregation layer thickness is decreased by about 87%, and the ingot can be homogenized at a high temperature by using the heat of the feed itself.

In order to achieve the combination of mechanical and corrosion properties for the Al-Mg-Mn alloy, a novel combination of pre-deformation under tension and an annealing process was investigated on the microstructure and properties of the Al-6Mg-1.0Mn extruded wide reinforcing plate. This was conducted by means of a tensile test, an intergranular corrosion test, scanning electron microscopy (SEM), and transmission electron microscope (TEM) experiments. The results showed that when the pre-deformation under tension in the range of 10–14%, the corrosion performance is first decreased, and then increases with the increase in temperature, becoming stable at 300 °C. After stabilization annealing at 300 °C for 2 h and then sensitizing at 150 °C for 10–200 h, the intergranular corrosion resistance of the aluminum alloy first decreases and then increases as the sensitization time is prolonged. When the sensitization time exceeds 50 h, the intergranular corrosion resistance is significantly improved. After 14% pretension and stabilization annealing at 300 °C for 2 h, the tensile strength, yield strength, and elongation of the alloy reached 360 MPa, 205 MPa, and 18.5%, and a good combination of strength and corrosion resistance of Al-Mg-Mn alloys could be obtained. These excellent properties were attributed to the continuous distribution of β-phase at the grain boundaries, and the combination of pre-deformation under tension with the annealing process promotes the dynamic precipitation of nanoparticles and the formation of substructure.

In order to understand the constitutive behavior of as-cast AZ80 with large grain size, the uniaxial hot compression tests were carried out over a series of isothermal upsetting experiments. The maximum deformation degree was 65%. The experimental temperatures were 523 K, 573 K, 623 K and 673 K and the strain rate was 0.001 s−1, 0.01 s−1, 0.1 s−1, and 1 s−1. The stress–strain curves can be divided into three stages which are work hardening stage, softening stage, and steady-state stage at low strain rate and high temperature, while the steady-state stage cannot be observed at low forming temperature and high strain rate because of incomplete dynamic recrystallization. The Arrhenius type relation predicts the peak stress with high accuracy but cannot satisfy the strain relevant requirement. The Johnson–Cook model shows an inappropriate ability to describe the constitutive behavior in this case. Therefore, a new mathematic model (a segmented model) with high prediction accuracy based on the modified Arrhenius type relation (including strain rate) and Johnson–Cook model is proposed. The modified Arrhenius type relation is used to reflect the constitutive behavior before the peak strain and the modified Johnson–Cook model is aimed at showing the stages after peak strain. Keywords: Magnesium alloy, Hot compression, Constitutive behavior, Mathematic model, Arrhenius type equation, Johnson–Cook model

DNA origami is the application of self-assembly in nanotechnology. The combination of DNA origami and hybridization chain reaction is one of the important application methods of DNA origami. In this paper, DNA origami is used to design the cipher pattern on the base of origami. The cipher chain, which is put into the reaction solution, hybridizes with the molecular beacon and the hairpin structure that form the cipher pattern to build a DNA origami model that can decode the pattern. The cipher chain consists of the starting chain and the intermediate chain. When the cipher is correct, the cipher chain can open the molecular beacon and the hairpin structure to display the cipher pattern on the origami base in the solution.

Through gradient hot rolling, a transition zone from the initial undeformed to 30% deformed microstructure was obtained in the 6 mm thick 1561 aluminum alloy hot rolled plate. The effect of gradient deformation on the evolution process of structure and texture characteristics to 1561 aluminum alloy were systematically investigated by X-ray diffractometer (XRD), optical microscope (OM), and electron back-scattered diffraction (EBSD) in this paper. The results showed that after gradient hot rolling, the grains were elongated along the rolled direction, and the average grain size decreased from 18.95 μm to 1.19 μm. After annealing, the average grain size decreased from 28.34 μm to 10.69 μm. The fraction of dynamic recrystallization is low in all cases. With the increase in gradient deformation, the fraction of the deformed texture (110) Goss, (110) Brass and fiber texture increased under the action of shear strain, the hardness value of annealed 1561 aluminum alloy ranged from 83.8 HV up to as high as 104 HV, and the electrical conductivity (EC) value increased from 23.5% IACS to 24.3% IACS. Significantly, with the increment of the deformation, the dislocation density increases 2.4 × 1013 m−2 of the annealed hot rolled plates, which should be responsible for the hardness increase. While the structure of the alloy becomes more orderly, the EC increases. Work hardening, fine-grain strengthening and texture all influence the mechanical properties of the gradient hot rolled 1561 aluminum alloy plate.

The film flow between the disks is the critical factor in the design of hydro-viscous drive. In the previous work dealing with the flow in the gap, few authors considered the effect of non-isothermal interface on the flow. In order to investigate the dynamic behavior of the oil film between non-isothermal friction pair in hydro-viscous drive, the flow field of the oil film between the disks is presented with consideration of four representative temperature models. Parameters related to the flow, such as temperature, pressure, velocity, shear stress and viscous torque are obtained by means of numerical simulation. The results show that non-isothermal interface results in temperature distribution profiles that diverge from the ideal parabolic curve. Both the discrepancies about film pressure and radial velocity at the outlet are vulnerable to temperature variation derived from a set of frictional pair. Tangential velocity profiles diverge from inlet to outlet due to the non-isothermal interface. Shear stress profiles show the opposite trend caused by the substantial variation about the oil viscosity. The research results lay a theoretical foundation for the reasonable designs of hydro-viscous drive.

Background/Aims: Traumatic brain injury (TBI) is a major public health problem in the world and causes high rates of mortality and disability. Recent evidence suggests that vitamin D (VD) has neuroprotective actions and can promote function recovery after TBI. In vitro and in vivo studies have demonstrated that autophagy could be enhanced following supplementation with an active metabolite of VD (calcitriol). However, it is unclear whether autophagy participates in the protective effects of calcitriol after TBI. To test this hypothesis, we examined the protective effects of calcitriol on TBI-induced neurological impairment and further investigated whether calcitriol could modulate autophagy dysfunction-mediated cell death in the cortex region of rat brain. Methods: Eighty-five male rats (250-280 g) were randomly assigned to sham (n=15), TBI model (TBI, n=35) and calcitriol treatment (calcitriol, n=35) groups. Rats were injected intraperitoneally with calcitriol (1 µg/kg) at 30 min, 24 h and 48 h post-TBI in the calcitriol group. The lysosomal inhibitor, chloroquine (CQ), was used to evaluate autophagic flux in the TBI and calcitriol groups. Neurological functions were evaluated via the modified neurological severity score test at 1-7 days after TBI or sham operation, and the terminal deoxynucleotidyl transferase-mediated FITC-dUTP nick-end labeling method was used to evaluate the ability of calcitriol to inhibit apoptosis. The expression of VDR, LC3 and p62 proteins was measured by western blot analysis at 1, 3 and 7 days post-injury Results: Calcitriol treatment attenuated mNSS at 2-7 days post-TBI (P < 0.05 versus TBI group). Calcitriol dramatically increased VDR protein expression compared with the untreated counterparts at 1, 3 and 7 days post-TBI (P < 0.05). The rate of apoptotic cells in calcitriol-treated rats was significantly reduced compared to that observed in the TBI group (P < 0.05). The LC3II/LC3I ratio was decreased in the cortex region at 1, 3 and 7 days post-TBI in rats treated with calcitriol (p < 0.05 versus TBI group), and the p62 expression was also attenuated (p < 0.05 versus TBI group). The LC3II/LC3I ratio in the calcitriol group was significantly increased when pretreated with CQ (P < 0.05). Conclusion: Calcitriol treatment activated VDR protein expression and attenuated neurological deficits in this rat TBI model. The protective effects might be associated with the restoration of autophagy flux and the decrease in apoptosis in the cortex region of rat brain.

Background/Aims: Intracerebral hemorrhage (ICH) occurs in hypertensive patients and results in high rates of mortality and disability. This study determined whether bone marrow mesenchymal stem cell (BMSC) transplantation affects axonal regeneration and examined the underlying mechanisms after the administration of PD98059 (p-ERK1/2 inhibitor) or/ and LY294002 (PI3K inhibitor). The hypothesis that was intended to be tested was that BMSC transplantation regulates the expression of growth-associated protein-43 (GAP-43) via the ERK1/2 and PI3K/Akt signaling pathways. Methods: Seventy-five male rats (250–280 g) were subjected to intracerebral blood injection and then randomly received a vehicle, BMSCs, PD98059 or LY294002 treatment. Neurological deficits were evaluated prior to injury and at 1, 3 and 7 days post-injury. The expression of GAP-43, Akt, p-Akt, ERK1/2, and p-ERK1/2 proteins was measured by western blot analysis. Results: BMSC transplantation attenuated neurological deficits 3-7 days post-ICH. The expression of GAP-43 was increased 3 days following BMSC transplantation. However, this increase was inhibited by either PD98059 or LY294002 treatment. Treatment with both PD98059 and LY294002 was more effective than was treatment with an individual compound. Conclusion: BMSC transplantation could attenuate neurological deficits and activate axonal regeneration in this rat ICH model. The protective effects might be associated with increased GAP-43 expression by activating both the ERK1/2 and PI3K/Akt signaling pathways.

The influences of Li content on the corrosion behavior of TC4 (Ti6Al4V) titanium alloy were explored when the TC4 titanium alloy was immersed in Al–Li alloy melt containing 0%, 1%, and 2% lithium at 680 °C, 700 °C, and 720 °C for 0.5 h, 1 h, and 2 h. The structure and growth law of the diffusion reaction layer at solid–liquid interface were studied, and the growth kinetic equation of the diffusion reaction layer was established. In addition, Ti content in Al–Li alloy melt was determined and its dissolution rate was calculated. The results showed that with the increase of lithium content in the melt, the thickness of the diffusion reaction layer (DRL) between TC4 titanium alloy and the melt increased significantly, and the activation energies of the diffusion reaction obtained were 141.28 kJ·mol−1 in liquid Al, 86.62 kJ·mol−1 in liquid Al–1Li alloy, and 43.42 kJ·mol−1 in liquid Al–2Li alloy, respectively. The dissolution rate of Ti in Al–Li alloy melts increased with the increase of lithium content in melts. When the holding time reached 3 h in a TC4 crucible, the content of Ti dissolved in the Al–2Li alloy melt was 0.105 wt%.

Effects of various rare-earth elements (RE: Gd, Nd and Ce) additions on microstructures and mechanical properties of ultra-light dual phase Mg-9Li-0.4Zr alloy were investigated. The results indicated that Mg-9Li-5RE-0.4Zr alloys exhibited α-Mg, β-Li and RE-containing intermetallic compound structures. 5 wt.% Gd, Nd and Ce additions enhanced the strength properties of as-extruded Mg-9Li-0.4Zr alloy, but greatly deteriorated the ductility. The final mechanical properties of Mg-9Li-5RE-0.4Zr alloys were 161MPa∼167MPa in ultimate strength, 141MPa∼156MPa in yield strength and 20.8%∼32.5% in elongation. Heat treatment was hardly able to improve the mechanical properties for Mg-9Li-5RE-0.4Zr alloys.

Considering the influence of the fluid-inertia item on dynamic transmission characteristics during soft-start of hydro-viscous drive (HVD), theoretical models were derived with the aim of revealing the effect of engagement pressure, lubricant viscosity, viscosity-temperature characteristics, surface roughness and the ratio of inner and outer radius of plates on total torque and viscous torque. The results indicate that the increase of engagement pressure and lubricant viscosity shortens soft-start time and increases peak total torque in the stage of mixed lubrication. The decrease of surface roughness and effective contact area of plates can both shorten soft-start time. And yet two cases of time to reach peak total torque are in different stages. Fluid-inertia item included can help to avoid fluctuation of the total torque while increasing lubricant viscosity or reducing surface roughness. It can increase soft-start time obviously when considering viscosity-temperature characteristics. In short, the research reveals the influence rules of the fluid-inertia item on dynamic transmission characteristics of HVD; additionally, fluid-inertia item included contributes to reduce oscillation of the total torque and the decline in efficiency. Therefore, the research results lay a theoretical foundation for the design of high-power HVD device.

Mg–9Gd–3Y–1.5Zn–0.8Zr alloys own high strength, good heat and corrosion resistance. However, it is difficult for the fabrication of large-scale billets, due to the poor deformation ability and strong hot-crack tendency. This work investigated the casting process on the microstructures and flow stress behaviors of the semi-continuous casting billets for the fabrication of large-scale Mg–9Gd–3Y–1.5Zn–0.8Zr billets. The casting process (electromagnetic intensity and casting speed) shows outstanding effects on the microstructures and flow stress behavior of the billets. The billets with the specific casting process (I = 68 A, V = 65 mm/min) exhibit uniform microstructures and good deformation uniformity.

Background: Despite increasing acceptance of endovascular coiling for treating anterior communicating artery (ACoA) aneurysms, anterior circulation cerebral infarction (ACI) after embolization remains a limitation. With higher incidence, higher morbidity and higher mortality, it is one of the main factors influencing the ACoA aneurysms prognosis. Determining the risk factors leading to ACI after embolization will have clinical significance. Through retrospective case analysis, this study investigated the risk factors related to ACI after embolization in order to provide information to serve the clinical practice. Materials and Methods: A retrospective review was performed of patients who had undergone coiling of ACoA aneurysms from 2008 to 2012. All patients had ruptured prior to the completion of embolization. Cases with acute stroke symptoms without alternative diagnoses after embolization were diagnosed as ACI. A total of 32 risk factors such as age, sex, hypertension, diabetes mellitus, modified Fisher grade, Hunt-Hess grade, ventricular hemorrhage, etc. were analyzed using univariate and logistic regression analysis. Results: Univariate analysis showed that negative fluid volume balance (P = 0.041

The effect of V addition on the hot deformation behavior of AA5083 was investigated. Single axial compression tests were conducted on the cast and homogenized samples with strain rates ranging from 0.01 to 10 s−1 and deformation temperatures ranging from 300 to 450 °C. The results showed that the contents of V (0−0.10, in wt.%) do not change the grain size of alloy 5083 significantly in the as cast and homogenized conditions, but the formation of fine Al3V particles in the alloy with an addition of 0.05 wt.% V can increase the flow stress, and its activation energy is 10.0% higher than that of V-free alloy 5083. The processing maps show that the appropriate process domain for alloy 5083 with 0.05 wt.% V changes at different true strains. The mechanism for deformation softening is discussed as well.

In this paper, the micro-structure and solid solubility of 2A97 aluminum-lithium alloy ingots prepared by conventional direct chill (DC) casting and low frequency electromagnetic casting (LFEC) as well as the density of precipitates and tensile properties of 2A97 alloy after T6 treatment were investigated. The results show that the low-frequency electromagnetic field during casting had a remarkable effect on the refinement of micro-structure and solid solubility of alloying elements within the grains, which is very helpful to obtain a large number of fine, uniformly-distributed T1 phases. The mechanical properties of 2A97 alloy prepared by low frequency electromagnetic casting after T6 treatment were improved by obtaining a larger number T1 phases.

The hardness, toughness, wear resistance, and fatigue behavior of materials can be improved through a deep cryogenic treatment (DCT). During this treatment, low temperatures (−100 °C to −196 °C) are maintained and then increased to room or higher. In this work, an indirect-extrusion plate of 7A99 ultra-high strength aluminum alloy was subjected to a T6 (peak aging) treatment and a T6-DCT treatment. The influence of the T6-DCT treatment on the mechanical properties, grain morphologies, precipitates, and atom−cluster distribution was investigated via tensile testing, electron backscatter diffraction, transmission electron microscopy, and three-dimensional atom probe analysis. The tensile strength (maximum: 705 deep cryogenic treatment), yield strength (maximum: 678 MPa), and elongation (maximum: 14%) of the T6-DCT-treated alloy were higher than those of the T6-treated alloy. Moreover, the T6-DCT treatment resulted in (i) grain size refinement and increased uniformity of the microstructure (homogeneous distribution of η’-MgZn2- and η-phase precipitates), and (ii) reduced segregation degree of Zn, Mg, and Cu atoms in the matrix (fraction of small atom clusters (sizes: 10−20 nm, 20−50 nm) increased, fraction of large clusters (size: >1,000 nm) decreased). Therefore, DCT can refine the precipitates and increase the uniformity of the precipitate distribution, thereby improving the strength and plasticity of the alloy.

The growth of MnSn2 phase during the solidification process of Sn-Mn alloy was crystallographically investigated. The results show that the non-faced spherical caps of the MnSn2 crystals follow the continuous growth mechanism to grow rapidly along the direction, while the side surfaces the two-dimensional nucleation mechanism to form the low index {100} and {110} facets. An interface structure analysis indicates that the atom planes within the {100} interplanar spacing period (IPSP) has a lower average reticular density than those within the {011} IPSP. This leads to the faster growth rates and thus the shortening and disappearance of the {100} side facets. As a consequence, the partially faceted (i.e., non-faceted spherical caps and faceted side surfaces) MnSn2 crystals follow an octagonal-base/spherical-cap geometric model (few crystals possess square bases) in three dimensions.

The billets of a new super-high strength Al-Zn-Mg-Cu alloy in 200 mm diameter were produced by the processed of low frequency electromagnetic casting (LFEC) and conventional direct chill(DC)casting, respectively. The effects of low frequency electromagnetic field on temperature field of the melt in the hot-top were investigated by temperature thermocouples into the casting during the processes. The results show that during LFEC process the temperature field in the melt applying the hot-top is very uniform, which is helpful to reduce the difference of thermal gradients between the surface and the center, and then to reduce the thermal stress and to eliminate casting crack.

AISn8Pb2Si25Cu0.8Cr0.2(ASP) is a new bush material with high performance, but its bad lasticity limits its application. By studying the effect of silicon content on the performance of this bush material, it was found that the alloy performance and the distribution of tin and lead were affected by the silicon content. When the silicon content was 2.5%,most of the silicon recipitated along the grain boundary, and most of the lead and tin located along the grain boundary continuously, this resulted in the decrease of the bush material's performance. When the silicon content decreased to 1.0%,it distributed more uniformly, the tin and lead phases were spheroidized and became discontinuous, the performance of ASP material was then greatly increased.

The super high strength aluminum alloy ingots with 100 mm in diameter were cast by the process of low-frequency electromagnetic horizontal continuous casting (LFEHC) and the effect of electromagnetic field on the as-cast microstructure was studied. Results show that microstructure of the sample prepared by the LFEHC process was greatly refined. Microstructures at the border and the center of the ingots were fine, uniform and rosette-haped.Electromagnetic frequency plays a key role in microstructure refining. Fine and uniform microstructures can be obtained with optimal electromagnetic frequency. In this experiment, under a frequency of 30 Hz the microstructure was the finest and the most uniform.

Effects of low frequency electromagnetic field on grain boundary segregation in horizontal direct chill (HDC)casting process was investigated experimentally. The grain boundary segregation and microstructures of the ingots,which manufactured by conventional HDC casting and low frequency electromagnetic HDC casting were compared.Results show that low frequency electromagnetic field significantly refines the microstructures and reduces grainboundary segregation. Decreasing electromagnetic frequency or increasing electromagnetic intensity has great effects in reducing grain boundary segregation. Meanwhile, the governing mechanisms were discussed.

Due to the unique capacity for structural control, high magnetic fields (HMFs) have been widely applied to the solidification process of alloys. In zinc-based alloys, the primary zinc-rich crystals can be dendritic or needle-like in two dimensions. For the dendritic crystals, their growth pattern and orientation behaviors under HMFs have been investigated. However, the three-dimensional crystallographic growth pattern and the orientation behaviors of the needle-like primary zinc-rich crystals under a high magnetic field have not been studied. In this work, a ternary Sn-Zn-Bi alloy was solidified under different HMFs. The above-mentioned two aspects of the needle-like primary zinc-rich crystals were characterized using the Electron Backscattered Diffraction (EBSD) technique. The results show that the primary zinc-rich crystals are characterized by the plate-shaped faceted growth in three dimensions. They grow in the following manner: spreading rapidly in the {0001} basal plane with a gradual decrease in thickness at the edges. The application of HMFs has no effect on the growth form of the primary zinc-rich crystals, but induces their vertical alignment. Crystallographic analysis indicates that the vertically aligned primary zinc-rich crystals orient preferentially with the c-axis perpendicular to the direction of the magnetic field.