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For the development of new energy automobile industry and the trend of automobile lightweight have put forward a huge demand for high-strength lightweight materials, so developing high strength aluminum alloys is particularly momentous. As the most widely used aluminum alloy, 6000 series aluminum alloys (Al–Mg–Si alloys) have the advantages such as better mechanical properties, outstanding welding properties, excellent formability and fine processing capability, and therefore have obtained great attention as the structural materials. In addition, the Al–Mg–Si alloys with low density and corrosion resistance not only reduce the total weight of the car, but also extend the service life when subjected to chemical corrosion, which effectively achieve energy saving and emission reduction. This paper summarizes the research progress of 6000 series aluminum alloys, in particular, and reviews the methods of microalloying and particle strengthening, and their effects on the microstructure and properties of the alloy, thus providing a reference for the subsequent development of high-performance aluminum alloys in automobile and aerospace industries.

Rapid growth in industrial sectors such as automotive and shipbuilding has highlighted the significance of strip casting technology to produce lightweight alloys, particularly aluminum alloys widely used in both industrial production and daily life. Twin-roll casting (TRC), as an economically and environmentally friendly method for slab/strip production and processing, has attracted significant interest from researchers. However, the development of TRC aluminum alloys faces many challenges due to limited understanding of microstructural characteristics and control mechanisms. To further enhance comprehension of TRC aluminum alloys, this article reviews the influencing parameters, control methods, and existing issues related to TRC sub-rapid solidification (SRS) microstructure. It firstly summarizes TRC equipment types and their solidification characteristics, followed by a detailed analysis on key parameters affecting the evolution of TRC microstructure including rolling speed, roll separation force (RSF), and heat transfer coefficient (HTC). Finally, solutions to TRC defects are summarized and evaluated alongside their underlying mechanisms. This article provides a comprehensive review of the characteristics and control mechanisms of TRC microstructure while offering valuable insights for the future production of high-quality TRC aluminum strips.

In the global pursuit of energy conservation, reduction in consumption and emissions, as well as lightweighting, 5xxx-series aluminum alloys have emerged as a promising lightweight and high-strength material with a wide range of applications in aerospace, transportation, building structures, medical devices, and more. However, it is worth noting that 5XXX-series aluminum alloys belong to a category of non-heat-treatable reinforced aluminum alloys with limited means of enhancing their properties through heat treatment. Consequently, the development of high-performance 5XXX-series aluminum alloys poses a significant challenge. This paper provides an overview of the research progress on 5xxx-series aluminum alloys while discussing the current state of research regarding the influence of microalloying elements on their microstructure and properties. Furthermore, it elucidates the emerging trends in synergistic regulation between deformation processes and heat treatment processes for enhancing organizational refinement and improving alloy properties. Additionally, this study analyzes the reinforcement mechanism responsible for the exceptional properties exhibited by 5xxx-series aluminum alloys. Lastly, it discusses the exceptional properties exhibited by 5xxx-series alloys along with their primary areas of application. The findings presented herein can serve as a valuable reference for future advancements in advanced high-performance 5xxx-series aluminum alloys.

Rock breaking has always been a challenging problem that must be solved in projects such as excavating mountains, drilling wells, and constructing railways. Among the rock-breaking cutter steels, AISI H13 steel and wear-resistant high manganese steel have become the best choices. From the characteristics and failure modes of the two, rock-breaking cutter steels should simultaneously have high strength, high toughness and high wear resistance to avoid short-term fracture/damage and cost increase. Analyzing the problems existing in the molding process of rock-breaking cutter steels such as die casting, forging, and hot stamping, traditional strengthening technologies such as alloying optimization, heat treatment, and surface treatment can achieve certain performance enhancement. After reaching the limits of traditional strengthening technologies, a series of nanoparticle strengthening technologies came into being. The selection, addition amount, and addition method of nanoparticles all affect the microstructure, mechanical properties and wear. To this end, this article summarizes the research progress and challenges of rock-breaking cutter steels, and discusses traditional strengthening technologies and mainstream nanoparticle strengthening technologies. It provides a reference for the future development of high-quality and high-performance rock-breaking cutter steels, with aim to simultaneously expand their application potentials to other fields.

The further development of lightweight and energy-saving engineering materials is a great challenge for scientists in the 21st century. Magnesium and its composites, as the metal materials with the lowest density among metal structural materials, have good thermal conductivity, good dimensional stability, high specific strength, good biocompatibility, which can meet the requirements of energy-saving, emission reduction, environmental protection. In recent years, magnesium and its composites have found the major applications in various fields such as aerospace, automotive industry, electronics and medical industry. However, the fabrication of magnesium matrix composites is difficult, and the deformation behaviors and strengthening mechanisms of particulate reinforced magnesium matrix composites have unique characteristics. This article reviews the recent research progress of the magnesium matrix composites, including different fabrication methods and strengthening mechanisms. According to the classification of solidification rate, the advantages and disadvantages of various techniques used to fabricate magnesium matrix composites were introduced. The traditional and novel fabrication techniques were discussed. The influence mechanisms of particulates on solidification microstructures, recrystallization behaviors, texture strength and twin behaviors of magnesium matrix composites during solidification and extrusion were summarized, and the roles of particulates in solidification and extrusion of magnesium matrix composites were analyzed. The strengthening mechanisms of particulates on the mechanical properties, corrosion resistance, fatigue resistance and creep resistance of magnesium matrix composites were revealed. Finally, the development prospect and research direction of magnesium matrix composites were prospected. It is hoped that this paper can provide a reference for the further development of magnesium matrix composites.

Magnesium alloys, acknowledged as the environmentally-friendly engineering material of the 21st century, are ideally suited to fulfill the requirements of lightweight manufacturing. However, the poor plasticity of magnesium alloys hampers their further application. Subsequently, development of nanoparticle-reinforced magnesium matrix composites has been proven to be a promising way to enhance the comprehensive performance of magnesium alloys. The exceptional performance achieved even by very small number of reinforcements stimulated innovation in preparation techniques and in-depth analysis of reinforcement mechanisms. This paper provides a review on key challenges related to their processing, the profound impact of different micro-nanoparticle reinforcements on the microstructure and properties of magnesium matrix composites during solidification and subsequent deformation machining. Additionally, the reinforcement mechanisms of the excellent mechanical performance of the composites are also discussed. This study can provide valuable insights for the understanding of the selection of appropriate reinforcements and processing to optimize the performance nanoparticle-reinforced magnesium matrix composites.

This paper focuses on the effects and mechanisms of rare earth and calcium on the flame retardancy of magnesium alloys. Rare earth elements form dense composite oxide films on the surface of the melt, effectively inhibiting the progress of oxidation reactions and significantly increasing the ignition temperature of magnesium alloys. The mechanisms and optimal compositional ranges of different rare earth elements on the flame retardancy of magnesium alloys. Calcium form CaO-rich oxide films in magnesium alloys, which can effectively prevent oxygen diffusion and enhance the flame-retardant resistance of the alloy. When rare earth elements are compounded with calcium, a notable flame-retardant effect is observed. Composite application can maximize the flame-retardant effect of alloy elements while balancing the influence on various properties. Additionally, the authors illustrate through their own research that precise compositional optimization design is required to efficiently exploit the synergistic effects of RE and Ca and mitigate their adverse impacts.

Abstract Only a minority of cancer patients benefit from immune checkpoint blockade therapy. Sophisticated cross-talk among different immune checkpoint pathways as well as interaction pattern of immune checkpoint molecules carried on circulating small extracellular vesicles (sEV) might contribute to the low response rate. Here we demonstrate that PD-1 and CD80 carried on immunocyte-derived sEVs (I-sEV) induce an adaptive redistribution of PD-L1 in tumour cells. The resulting decreased cell membrane PD-L1 expression and increased sEV PD-L1 secretion into the circulation contribute to systemic immunosuppression. PD-1/CD80+ I-sEVs also induce downregulation of adhesion- and antigen presentation-related molecules on tumour cells and impaired immune cell infiltration, thereby converting tumours to an immunologically cold phenotype. Moreover, synchronous analysis of multiple checkpoint molecules, including PD-1, CD80 and PD-L1, on circulating sEVs distinguishes clinical responders from those patients who poorly respond to anti-PD-1 treatment. Altogether, our study shows that sEVs carry multiple inhibitory immune checkpoints proteins, which form a potentially targetable adaptive loop to suppress antitumour immunity.

Synergistic reinforcement of dual-phase particles with different sizes was always considered superior to single-phase reinforcement in composites, but there were few studies to investigate the role of each part in enhancing properties. In this work, 40 vol% (TiB2p-TiCp)/Al–Cu–Mg composites with different proportions of TiB2p and TiCp (3:1, 2:1, 1:1, 1:2 and 1:3), were fabricated by the combustion synthesis to contrast the strengthening effect of dual-phase particles from the interface stability and the characteristics of dual-phase particles. Calculated by the first principle, TiB2 (3.12 J/m2) presented better interfacial stability with Al matrix than TiC (1.61 J/m2). Under the circumstance of the same volume fraction, the composites with a higher proportion of TiB2p usually show higher yield and maximum compressive strength and effectively prevent the crack growth of composites. However, excess submicron sized TiB2p tends to produce cracks at the hexagon edge when the loads were applied and formed crack loops delaminating materials. When the TiB2p/TiCp proportion was 1:1, the plasticity and strength were beneficially balanced at the elevated temperature. Otherwise, the composite with TiB2: TiC = 3:1 possessed the best wear resistance (coefficient of friction: 0.22) at a sliding velocity of 0.32 mm/s, 30 N load) among other composites (AR12, AR11, AR21, and AR31) at 473 K, which reduced 45%, 64%, 73% and 86%, respectively. The main wear mechanism was abrasive wear when the TiB2 proportion was dominant. Submicron sized TiB2p with better interface bonding can keep the rigidity of the composites to resist the plastic flow, while TiC nanoparticles are easier to be extracted during the wear process.

Summary: Despite the success of programmed cell death 1 (PD-1)/programmed death ligand 1 (PD-L1) inhibition in tumor therapy, many patients do not benefit. This failure may be attributed to the intrinsic functions of PD-L1. We perform a genome-wide CRISPR synthetic lethality screen to systematically explore the intrinsic functions of PD-L1 in head and neck squamous cell carcinoma (HNSCC) cells, identifying ferroptosis-related genes as essential for the viability of PD-L1-deficient cells. Genetic and pharmacological induction of ferroptosis accelerates cell death in PD-L1 knockout cells, which are also more susceptible to immunogenic ferroptosis. Mechanistically, nuclear PD-L1 transcriptionally activates SOD2 to maintain redox homeostasis. Lower reactive oxygen species (ROS) and ferroptosis are observed in patients with HNSCC who have higher PD-L1 expression. Our study illustrates that PD-L1 confers ferroptosis resistance in HNSCC cells by activating the SOD2-mediated antioxidant pathway, suggesting that targeting the intrinsic functions of PD-L1 could enhance therapeutic efficacy.

Cold/hot forming wrought Al components with the apparent advantage of lightweight, outstanding formability and strength-ductility synergy are promising in structural materials field. Recrystallization is an indispensable process during deformation or heat treatment, whose driving force and microstructures have great relevance with the mechanical properties. In recent years, reinforcement and intermetallic particles have attracted great interests in precise intervening and controlling of recrystallization microstructures due to their immense potentials in regulating the driving and retarding force of recrystallization. Nevertheless, optimizing recrystallization microstructures of particle tailored wrought Al alloys is highly challenging due to the numerous affecting factors of particles (e.g., particle addition method, size, morphology, spatial distribution, coherency, and content, etc.) and the different driving force of static and dynamic recrystallization. To further impel the progress of recrystallization process of wrought Al alloy, this review gives an in-depth cognition of the roles of intermetallic and ceramic particles in recrystallization process of wrought Al alloys. The potential relevance between the particle characteristics, recrystallization driving force, and recrystallization microstructures in wrought Al alloys are summarized. The influences of regulated recrystallization microstructures on mechanical properties of wrought Al alloy are also overviewed. This review contributes to the comprehensive understanding of mechanisms of particle manipulated recrystallization evolution, and the future research orientations and development opportunities are prospected.

There is an increasingly urgent need of lightweight components in aerospace industry, among which aluminum (Al) alloys have been the optimal materials of choice for aircraft structural parts since being used in the Junkers F.13 aircraft in the 1920s. Compared to other metal materials, Al alloys have a lower density, and the use of Al alloys reduces the total weight of the aircraft and improves fuel efficiency and load capacity. Meanwhile, the strength and hardness of Al alloys with alloying and heat treatment can be significantly enhanced for uses in high loads and vibration environments. Furthermore, in the harsh aerospace environment, aircraft may receive various climatic conditions and chemical corrosion. Due to good corrosion and fatigue resistance, Al alloys demonstrate excellent performance under these conditions, ensuring the long–term service life of aircraft. In addition, Al alloys have good recyclability, and they can be recycled to reduce resource consumption and environmental load, in line with the principle of sustainable development. In recent years, although composites have been widely used in aerospace, high–strength Al alloys are still in an indispensable position. Therefore, this article reviews the progress and applications of Al alloys commonly used in aerospace. The common strengthening methods and advanced manufacturing and processing technologies of Al alloy are also discussed, which can provide references for the development of advanced high–performance aviation Al alloys in the future.

The mechanical performance of metal matrix composites strengthened with particles is predominantly contingent upon the attributes of the incorporated particles. Attaining the optimal particle size, morphology, and interfacial bonding within the composites is paramount for improving the comprehensive properties. In this study, an experimentally congruent model was devised to validate the feasibility of the model predicated on the actual microstructure of the composite. The modeling procedure encapsulated matrix and particle failure, as well as surface-based cohesive damage at the interface, to precisely portray the mechanism of action for the particle characteristics. Additionally, the mechanical behavior and failure evolution mechanism of the composites were simulated by manipulating the pertinent particle factors, including size distribution, interfacial strength, and morphology. The findings demonstrated that an appropriate size distribution between particles and more rounded particles can mitigate stress and strain concentration within the matrix interstitial to particles, resulting in a considerable enhancement in the mechanical performance of the composites. As the interfacial strength decreases, the initial failure progression of the composite shifts from initial cracking within the matrix induced by stress-strain concentration to interfacial failure caused by interfacial debonding, ultimately accelerating the failure of composite. This research will bolster the comprehension of the correlations between microstructural features and mechanical performance in metal matrix composites strengthened with particles, providing an innovative simulation-assisted experimental approach for the rapid development and preparation of novel metal matrix composites.

Al-Mg alloys are widely used as important engineering structural materials in aerospace engineering, transportation systems, and structural constructions due to their low density, high specific strength, corrosion resistance, welding capability, fatigue strength, and cost-effectiveness. However, the conventional Al-Mg alloys can no longer fully satisfy the demands of practical production due to difficulties caused by many defects. The high strength of Al-Mg alloys as non-heat treatment precipitation-strengthened alloys is achieved primarily by solid solution strengthening along with work hardening rather than precipitation strengthening. Therefore, severe plastic deformation (SPD) techniques can be often used to produce ultrafine-grained structures to fabricate ultra-high strength aluminum alloys. However, this approach often achieves the strengthening of material at the cost of reduced ductility. This paper comprehensively summarizes the various approaches of ultrafine/nanocrystalline materials for enhancing their plasticity, elaborates on the creation of a bimodal microstructure within the alloy, and discusses the formation of a nanotwin microstructure within the alloy and the incorporation of dispersed nanoparticles. The mechanisms underlying both the strengthening and toughening during large plastic deformation in aluminum alloys are summarized, and the future research direction of high-performance ultrafine crystalline and nanocrystalline Al-Mg aluminum alloys is prospected.

As an important part of die steels, hot-work die steels are mainly used to manufacture molds made of solid metal or high-temperature liquid metal from heating to recrystallization temperature. In view of the requirements for mechanical properties and service life for hot-work die steel, it is conducive to improve the thermal fatigue resistance, wear resistance, and oxidation resistance of hot work die steel. In this review, the main failure modes of hot-work die steel were analyzed. Four traditional methods of strengthening and toughening die steel were summarized, including optimizing alloying elements, electroslag remelting, increasing the forging ratio, and heat treatment process enhancement. A new nano-strengthening method was introduced that aimed to refine the microstructure of hot-work abrasive steel and improve its service performance by adding nanoparticles into molten steel to achieve uniform dispersion. This review provides an overview to improve the service performance and service life of hot work die steel.

Hot-work die steel with excellent strength and toughness can improve the precision of the die and prolong its service life. However, this is very difficult to achieve because of the opposing relationship between strength and plasticity. In this paper, we propose a combined approach of composition design and nanoparticle modification to overcome this difficulty. A novel hot-work die steel with reinforced trace nano-(TiC–TiB2) was fabricated using a traditional method. It had an improved microstructure, which consists of fine martensitic laths with high dislocation density, abundant small precipitates, and small and dispersed residual austenite. This expected microstructure improved the work hardening and uniform deformation ability of the steel, resulting in superior comprehensive mechanical properties. The yield strength and impact toughness of the novel hot-work die steel at room temperature were 1464 MPa and 597 J/cm2, respectively, increases of 121 MPa and 265 J/cm2, respectively, compared to the values for advanced and widely used traditional H13 steel. In particular, the impact toughness of the novel hot-work die steel at room temperature was approximately 42.5% and 33.0% higher than the impact toughness of H13 containing 0.01 and 0.02 wt% nanoparticles, respectively. Furthermore, the yield strength, ultimate tensile strength, and elongation of novel hot-work die steel at 500 °C were 1078 MPa,1103 MPa, and 40.4%, respectively, increases of 85 MPa, 86 MPa, and 4.2%, respectively, compared to values of the blank that was used in this work. This work shows new prospects for the development of hot-work die steel with excellent strength and toughness.

The optimal design of microstructure is the key to further improve the properties of particle reinforced metal matrix composites. In this study, in-situ TiB2 and TiC + TiB2 reinforced Cu matrix composites are used as examples to develop the microstructure-based representative volume element models to describe their damage evolution and strengthening mechanisms. The most critical features including size distribution and morphology of the particles as well as the fracture of metal matrix, brittle damage of ceramic particles and traction-separation debonding of the interface were integrated into the modeling. Simulation results show that the model could well predict the performance of the composite and reveal its damage mechanism. When the particle size is normally distributed, the composite exhibits higher strength due to the size effect of different particles, which is more consistent with the experimental result. Both matrix and ceramic particles in mixed-phase particle reinforced metal matrix composites can be subjected to higher stresses, which results in higher strength of (TiC + TiB2)/Cu composites. Additionally, the spherical TiC particles facilitate the relaxation of stress concentration within the composite, resulting in a synergistic enhancement of strength and ductility. Under compression, localized interface damage first appears around the sharp corners of the hexagonal particles and induces crack initiation toward the matrix. These microcracks are interconnected and propagate along the direction of high stress, eventually leading to the failure of the composite. This work provides the basis and new ideas to reveal the failure mechanism of composites and further optimize their configuration design.

Magnesium matrix composites are essential lightweight metal matrix composites, following aluminum matrix composites, with outstanding application prospects in automotive, aerospace lightweight and biomedical materials because of their high specific strength, low density and specific stiffness, good casting performance and rich resources. However, the inherent low plasticity and poor fatigue resistance of magnesium hamper its further application to a certain extent. Many researchers have tried many strengthening methods to improve the properties of magnesium alloys, while the relationship between wear resistance and plasticity still needs to be further improved. The nanoparticles added exhibit a good strengthening effect, especially the ceramic nanoparticles. Nanoparticle-reinforced magnesium matrix composites not only exhibit a high impact toughness, but also maintain the high strength and wear resistance of ceramic materials, effectively balancing the restriction between the strength and toughness. Therefore, this work aims to provide a review of the state of the art of research on the matrix, reinforcement, design, properties and potential applications of nano-reinforced phase-reinforced magnesium matrix composites (especially ceramic nanoparticle-reinforced ones). The conventional and potential matrices for the fabrication of magnesium matrix composites are introduced. The classification and influence of ceramic reinforcements are assessed, and the factors influencing interface bonding strength between reinforcements and matrix, regulation and design, performance and application are analyzed. Finally, the scope of future research in this field is discussed.

Incident Ti–Si poisoning when applying traditional agents of microstructure manipulation in Al–Si alloys is always adverse to realize multilevel microstructure control. This work combined the manipulation by physically formed in-situ nano-ceramics from Fe79.58B11.26Si9.26 amorphous alloy and the micro-alloying to comprehensively improve the microstructure configuration of Al–7.0Si–4.0Cu alloy. It was suggested that micro-alloying of Mg and Sb prominently refined α-Al dendrites and eutectic silicon. Micro-alloying with Mg increased the nucleating temperature of α-Al, meanwhile Mg atoms can hinder the growth of α-Al and eutectic silicon. Sb atoms can also be adsorbed to the growth interfaces of eutectic silicon hindering the growth process. On this basis, trace Fe79.58B11.26Si9.26 amorphous alloy brought further optimization on α-Al dendrites and eutectic silicon, especially Al2Cu and Mg2Si, realizing the multilevel microstructure control. In-situ Fe2B and Fe3Si nano-ceramics were confirmed to have low lattice misfits with α-Al and silicon, serving as efficient nucleation sites and growth retardants. After combined micro-alloying and manipulation, the mean sizes of α-Al and eutectic silicon were significantly refined by 72.7% and 79.9%, respectively, meanwhile, the ultimate tensile strength (UTS) and plastic strain (δ) were improved to 480 MPa and 9.4%, corresponding to 30.1% and 77.4% improvement, respectively. This work provides new mentality to realize multilevel microstructure control and improvement of strength–toughness synergy in Al–Si alloys.

Lightweight aluminum (Al) alloys have been widely used in frontier fields like aerospace and automotive industries, which attracts great interest in additive manufacturing (AM) to process high-value Al parts. As a mainstream AM technique, laser-directed energy deposition (LDED) shows good scalability to meet the requirements for large-format component manufacturing and repair. However, LDED Al alloys are highly challenging due to their inherent poor printability (e.g. low laser absorption, high oxidation sensitivity and cracking tendency). To further promote the development of LDED high-performance Al alloys, this review offers a deep understanding of the challenges and strategies to improve printability in LDED Al alloys. The porosity, cracking, distortion, inclusions, element evaporation and resultant inferior mechanical properties (worse than laser powder bed fusion) are the key challenges in LDED Al alloys. Processing parameter optimizations, in-situ alloy design, reinforcing particle addition and field assistance are the efficient approaches to improving the printability and performance of LDED Al alloys. The underlying correlations between processes, alloy innovation, characteristic microstructures, and achievable performances in LDED Al alloys are discussed. The benchmark mechanical properties and primary strengthening mechanism of LDED Al alloys are summarized. This review aims to provide a critical and in-depth evaluation of current progress in LDED Al alloys. Future opportunities and perspectives in LDED high-performance Al alloys are also outlined.

Background: After an acute stroke, highly reactive oxygen and nitrogen species (ROS/RNS) lead to microvessel injury and inhibit endogenous mediators to prevent the repair process of endothelial dysfunction and tissue injury. Among them, the peroxynitrite (ONOO−) generation as a result of nitric oxide (NO) and superoxide anion (O2·−) reaction contributes to ischemic brain injury. Purpose: To validate the targeted inhibition of ischemic injury's markers with the delivery of potent antioxidants such as β-carotene (BC) in lipid nanoparticles (LNPs) directly acting with ONOO− compound to prevent the breakdown of blood-brain barrier (BBB). Study design: In the current work, BC in polyethylene glycol (PEG) lipid nanoparticles (PEG-LNPs) with or without attached anti-nitrotyrosine antibody (3-NT) inhibits ONOO− generation in the transient middle cerebral artery occlusion (tMCAO) model. Transmission electron microscopy (TEM) was used to examine structural change in LNPs with or without 3-NT antibody attachment. Fluorescence imaging was employed to study drug encapsulated PEG-LNPs accumulation in mice brain following MCAO and spectrophotometry for the in-vitro drug release profile. Immunoblotting using antibodies specific for spectrin and calcineurin, occludin and ZO-1 and other targets was utilized. The NP3 fluorescent probe was used for the detection of ONOO−generation. Evans Blue was injected 24 h after tMCAO in vehicle and BC PEG-LNPs with 3-NT antibody treated animal groups to observe the tight junction breakdown. Results: The fluorescence's data reveals that attachment of 3-NT antibody has directed the delivery of BC to the ischemic ipsilateral region. BC, as well, is found effective to improve infarct volume and neurological deficit by neuronal protection by inhibiting spectrin and calcineurin (CaN) breakdown. Furthermore, inhibition of ONOO−generation is observed in NP3 probe incubation of brain slices and protects BBB from breakdown in Evans blue extravasation. Conclusion: The current work suggests that inhibiting ONOO−at ischemic site protects the brain microvessels from injury. 3-NT/BC/LNPs carrier system is potentially efficient in delivering BC at the site of ONOO−generation, and possibly suitable for ischemic region-targeted therapy.

In the general environment of lightweight automobiles, the integrated die-casting technology proposed by Tesla has become the general mode to better achieve weight reduction in automobiles. The die-casting mold required by integrated die-casting technology has the characteristics of large scale and complexity. Hence, higher requirements are put forward for the comprehensive performance of the die steel. Despite the stagnation in the progress of conventional strengthening methods, enhancing the performance of die steel has become increasingly challenging. Indeed, it necessitates exploring novel die steel and optimizing heat treatment and reinforcement technologies. This article summarizes and analyzes the development status of die steel and corresponding heat treatment and microstructure manipulation as well as strengthening methods and elaborates on an excellent nano-strengthening technology. Furthermore, this review will aid researchers in establishing a comprehensive understanding of the development status of die steel and the processes utilized for its strengthening. It will also assist them in developing die steel with improved comprehensive performance to meet the high demand for mold steel in the integrated die-casting technology of the new era.

It is well known that the development of lightweight alloys with improved comprehensive performance and application value are the future development directions for the ultra-high-strength 7xxx series Al-Zn-Mg-Cu alloys used in the aircraft field. As the lightest metal element in nature, lithium (Li) has outstanding advantages in reducing the density and increasing the elastic modulus in aluminum alloys, so Al-Zn-Mg-Cu alloys containing Li have gained widespread attention. Furthermore, since the Al-Zn-Mg-Cu alloy is usually strengthened by aging treatment, it is crucial to understand how Li addition affects its aging precipitation process. As such, in this article, the effects and mechanism of Li on the aging precipitation behavior and the impact of Li content on the aging precipitation phase of Al-Zn-Mg-Cu alloys are briefly reviewed, and the influence of Li on the service properties, including mechanical properties, wear resistance, and fatigue resistance, of Al-Zn-Mg-Cu alloys are explained. In addition, the corresponding development prospects and challenges of the Al-Zn-Mg-Cu-Li alloy are also proposed. This review is helpful to further understand the role of Li in Al-Zn-Mg-Cu alloys and provides a reference for the development of high-strength aluminum alloys containing Li with good comprehensive properties.

We intended to characterize functional relevance of microRNA (miR)-224-3p in endothelial cell (EC) apoptosis and reactive oxygen species (ROS) accumulation in atherosclerosis, considering also the integral involvement of histone deacetylase 1 (HDAC1)-mediated hypoxia-inducible factor-1α (HIF1α) deacetylation. The binding affinity between miR-224-3p and Fos-like antigen 2 (FOSL2) was predicted and validated. Furthermore, we manipulated miR-224-3p, FOSL2, HDAC1, and HIF1α expression in oxidized low-density lipoprotein (ox-LDL)-induced ECs, aiming to clarify their effects on cell activities, inflammation, and ROS level. Additionally, we examined the impact of miR-224-3p on aortic atherosclerotic plaque and lesions in a high-fat-diet-induced atherosclerosis model in ApoE−/− mice. Clinical atherosclerotic samples and ox-LDL-induced human aortic ECs (HAECs) exhibited low HDAC1/miR-224-3p expression and high HIF1α/FOSL2 expression. miR-224-3p repressed EC cell apoptosis, inflammatory responses, and intracellular ROS levels through targeting FOSL2. HIF1α reduced miR-224-3p expression to accelerate EC apoptosis and ROS accumulation. Moreover, HDAC1 inhibited HIF1α expression by deacetylation, which in turn enhanced miR-224-3p expression to attenuate EC apoptosis and ROS accumulation. miR-224-3p overexpression reduced atherosclerotic lesions in vivo. In summary, HDAC1 overexpression may enhance the anti-atherosclerotic and endothelial-protective effects of miR-224-3p-mediated inhibition of FOSL2 by deacetylating HIF1α, underscoring a novel therapeutic insight against experimental atherosclerosis.

In this study, different contents (0.0, 0.1, 0.2, and 0.4 wt.%) of Zr55Cu30Al10Ni5 amorphous alloys (Zr-AA) are used to manipulate hypereutectic Al-Si alloys. The edge-to-edge model shows that there is a perfect lattice matching between the crystallized phases and α-Al and Si phases. The thermal analysis of solidification behavior of hypereutectic Al-Si alloys unmanipulated and manipulated by Zr-AA, indicates that the addition of Zr-AA greatly promotes the nucleation of primary Si and significantly accelerates the process of eutectic reaction. When manipulated by the optimal content of 0.2 wt.% Zr-AA, the sizes of α-Al dendrites and primary Si decrease from 212.46 μm and 19.24 μm to 143.39 μm and 16.47 μm, respectively. The eutectic Si changes from needle-like to rod-like and exhibits a mean size decrease from 20.21 μm to 11.69 μm. Meanwhile, alloys exhibit ultimate tensile strength of 362 MPa and fraction strain of 2.21% after 0.2 wt.% Zr-AA manipulation, which are 23% and 37% higher than those of the unmanipulated alloy (295 MPa and 1.61%). The strengthening mechanisms of hypereutectic Al-Si alloys manipulated by in situ nanocrystals crystallized in the melt are mainly attributed to the fine grain strengthening effect and precipitation strengthening effect. The increase in plasticity is due to the refinement and morphology improvement of Si phases.

Based on the principle of bionics, the lightweight and high-strength the Neptune’s shell was chosen as a bionic model for this study due to its light weight and high strength. Micro-nano mixed-scale dual-phase reinforced aluminum matrix composites were prepared by one-step densification of combustion synthesis combined with hot pressing. We aimed to control the particle size of the ceramic and the ratio of the soft and hard phases by controlling the composition of the composite, and to study the mechanical properties of the biomimetic structure of the composite at normal and high temperatures. The results showed that as the aluminum content in the composite decreased, the ceramic particle size increased and the ceramic particles became evenly distributed in the matrix. Compression testing showed that as the ceramic volume fraction increased the ultimate compressive strength (σUCS) and fracture strain (εf) first increased and then decreased, both at room temperature and at 473 K and 523 K. (TiB2-TiCx)/Al-Cu-Mg composites of 40 vol.% exhibited optimal compressive properties at room temperature and at high temperatures. The increase in the size of the ceramic particles caused an increase in the spacing between the particles, which also weakened the bonding strength between the ceramic particles and the aluminum matrix. Therefore, when the ceramic volume fraction exceeded 40% by volume, the compression properties of the composite tended to decrease. The coupling effect of the layered structure and the soft-hardened structure played a key role in the stability of the biomimetic composite.

In this study, the thermal stability of Ni–Nb–Ti metallic glasses was investigated under isothermal and non-isothermal conditions. The effectiveness of NiTi phases, one of the nanosized crystallized phases, as grain refiners for Al–Cu alloys was also investigated from a crystallographic point of view using the edge-to-edge matching (E2EM) model. Thermal analysis showed that NiTi phases promote solidification of α-Al, and these nanocrystalline phases also promote an Al–Cu eutectic reaction and inhibit the growth of eutectic phases. A significant refining effect of α-Al grains from 402.7 μm to 69.1 μm was achieved with 0.05 wt.% nanocrystalline phases. Simultaneously, values for yield strength, ultimate tensile strength and fracture strain of inoculated Al–Cu alloys were increased by 18%, 13% and 78% to 363.2 MPa, 534.3 MPa and 11.92%, respectively, when compared with those of uninoculated Al–Cu alloys. Strengthening mechanisms of Al–Cu alloys manipulated by the nanocrystalline phases are grain boundary strengthening and precipitation strengthening.

Copper matrix composites doped with ceramic particles are known to effectively enhance the mechanical properties, thermal expansion behavior and high-temperature stability of copper while maintaining high thermal and electrical conductivity. This greatly expands the applications of copper as a functional material in thermal and conductive components, including electronic packaging materials and heat sinks, brushes, integrated circuit lead frames. So far, endeavors have been focusing on how to choose suitable ceramic components and fully exert strengthening effect of ceramic particles in the copper matrix. This article reviews and analyzes the effects of preparation techniques and the characteristics of ceramic particles, including ceramic particle content, size, morphology and interfacial bonding, on the diathermancy, electrical conductivity and mechanical behavior of copper matrix composites. The corresponding models and influencing mechanisms are also elaborated in depth. This review contributes to a deep understanding of the strengthening mechanisms and microstructural regulation of ceramic particle reinforced copper matrix composites. By more precise design and manipulation of composite microstructure, the comprehensive properties could be further improved to meet the growing demands of copper matrix composites in a wide range of application fields.

The corrosion behavior of laser powder bed fusion produced (L-PBF-produced) titanium alloys involving flowing body fluid is still unclear. Therefore, this work investigates in vitro corrosion behavior and the characteristics of passive films formed on L-PBF-produced Ti–6Al–4V in both static and dynamic Hank’s solutions. Electrochemical measurements, immersion tests, X-ray photoelectron spectroscopy and scanning electron microscopy were conducted. In comparison to the L-PBF-produced Ti–6Al–4V in static Hank’s solution, the samples showed lower charge transfer resistance and higher passivation current density (anodic current density as well) in dynamic Hank’s solution. Meanwhile, a more apparent deposition of apatite and hydroxyapatite is found on the L-PBF-produced Ti–6Al–4V in dynamic Hank’s solution. Such outcomes mainly result from the enhancement of film/solution interfacial transportation in dynamic Hank’s solution. The dynamic Hank’s solution provides more calcium and phosphate ions to the surface of the passive film and also takes away the dissolved metal ions. Therefore, more salt deposition and a lower-quality passive film are found.

In this paper, we took cold-rolled Al-Cu5.0-Mg0.5-Si0.5 alloy as the research object. The roles of 0.1 wt% in-situ nano-TiC and nano-TiC-TiB2 in solid–liquid and solid-state transformations (solution plus aging precipitation) were systematically investigated and compared. We found that trace in-situ nanoparticles can stimulate the nucleation of α-Al dendrites and hinder their growth, meanwhile serving as the heat storage and heat sustained-release carriers during solid–liquid transformation. In the process of solid-state transformation, recrystallization nucleation is promoted, and grain boundaries are pinned by nanoparticles. Meanwhile, the nucleation of Al2Cu is accelerated, and refined Al2Cu distributes more uniformly. Besides, similarities and differences in the manipulation mechanisms of nano-TiC and nano-TiC-TiB2 during solid–liquid and solid-state transformations were analyzed. The mechanical properties and the responsible strengthening mechanisms were discussed in detail.

A kind of signal acquisition circuit and the related signal processing method of the capacitance electromagnetic flowmeter were introduced. The circuit can eliminate the influence of distributed capacitance on the input impedance of the operational amplifier, and greatly improve the input impedance of the detection circuit to overcome the disadvantage of high signal source impedance. The rotating capacitor filter is a signal processing method based on the phase-sensitive detection technology. It can extract the weak signal from the strong and wide-band background noise, so it is very suitable for the processing of capacitive electromagnetic flow signals. Through the comparison of the signal amplitude obtained at different flow rates and the comparison of signal spectrum components before and after the filter, the effectiveness of the bootstrap signal acquisition circuit and rotating capacitor filtering method is verified.

Abstract Background Immunoglobulin G4-related sialadenitis (IgG4-RS) is a newly recognized immune-mediated systemic disease. Despite its good response to steroid therapy, its treatment protocol is not standardized and the long-term outcome is controversial. The study was conducted to determine the short-term and long-term outcomes of IgG4-RS patients treated with glucocorticoids and steroid-sparing immunosuppressive agents, to analyze secretory function, serological and radiological changes in salivary glands and to assess the usefulness of serum IgG4 level as an indicator of disease activity. Methods IgG4-RS patients who were treated for more than 3 months were enrolled. Serological tests, salivary gland function assessment and computed tomography (CT) were performed before treatment and during follow up. The treatment outcomes in the short and the long term were evaluated, and the relationship between serum IgG4 level and salivary gland volume was analyzed. Results Glucocorticoids were used in all 43 patients and steroid-sparing immunosuppressive agents in 38 patients (88.4%). The follow-up period was 24.6 ± 14.9 months. Clinical remission was achieved in all patients after induction therapy. During short-term observation, salivary gland secretion significantly increased, and the serum IgG4 levels, the volumes and CT values of submandibular and parotid gland decreased significantly (P

In order to solve the problem that Hadoop cloud platform could not dynamically control user access request,a Hadoop cloud dynamic access control model based on user behavior assessment (DACUBA) was proposed.The model first collected the user instruction sequence in real time and the user behavior contour was obtained by parallel command sequence learning (PCSL).Then the global K model was established by using the forward profile,the subsequent sequence was classified and the classification results were evaluated.The evaluation results were combined with the improved Hadoop access control mechanism to make the cloud platform users’ access rights change dynamically with their own behaviors.Experimental results demonstrate that the model algorithm is effective and the dynamic access control mechanism is feasible.

Aiming at the defect of vote principle in random forest algorithm which is incapable of distinguishing the differences between strong classifier and weak classifier,a weighted voting improved method was proposed,and an improved random forest classification (IRFCM) was proposed to detect Android malware on the basis of this method.The IRFCM chose Permission information and Intent information as attribute features from AndroidManifest.xml files and optimized them,then applied the model to classify the final feature vectors.The experimental results in Weka environment show that IRFCM has better classification accuracy and classification efficiency.

AlCu alloys inoculated by in-situ nano-sized particles crystallized from Ni-Nb-Ti amorphous alloys were prepared by casting method in this work. Different compositions of Ni-Nb-Ti amorphous alloys significantly enhanced heterogeneous nucleation for α-Al and promoted obvious grain refinement of the AlCu alloys. It was found that 0.05 wt% Ni-Nb-Ti amorphous alloys addition caused a significant and efficient refinement on α-Al (from 200 μm to 39 μm) and θ′ phase (from 146.4 nm to 37.6 nm). The strength and ductility of the inoculated alloy were improved significantly at high temperature. The tensile strength and fracture strain of the alloy inoculated by 0.05 wt% Ni-Nb-Ti amorphous alloy for 20 min at 533 K under the strain rates of 10−1 s−1 were increased by 32.63% and 90.35% respectively, compared to those of the uninoculated alloy. The nano-sized NiTi particles contributed to the grain refinement of α-Al, and grain refinement shortened the solute atomic diffusion distance and refined θ′ phase during heat treatment, resulting in higher strength and plasticity at high temperature. The model developed for this new type AlCu alloy is found to be efficient in predicting the stress at 453 K–533 K under the strain rates of 10−4 s−1 to 10−1 s−1. Keywords: In-situ nanocrystals, Amorphous alloys, Microstructure refinement, Mechanical properties, Precipitates, Stress prediction model

The morphology of TiCx nanoparticles is one of the most significant inherent factors that influence their comprehensive performances and extensional applications. However, the design of TiCx nanoparticles and their growth morphologies manipulating in the Al melt are always in challenges, while the stoichiometric ratios controlled synthesis will show a promising prospect. In this study, TiCx ceramic nanoparticles with different stoichiometric ratios (x = 0.5, 0.625, 0.75, 0.875 and 1.0) were fabricated successfully by combustion synthesis in Al-Ti-C reaction system. Based on the evaluation of nanosized TiCx specific exposed planes in the Al melt, the stoichiometric ratios manipulated the Al/TiCx interface performances, including interfacial stability, the nature of bonding and the interface electron transfer were analyzed via first-principle calculation. With the increasing stoichiometric ratios, the TiCx(100) exposed planes in the Al melt gradually stabilized and became exposed, while the TiCx(111) planes showed poor stability and gradually shrank and disappeared. The corresponding morphology will also evolve from octahedron to truncated-octahedron then spheroid with increasing x. Moreover, those interface performances can be selectively controlled by the stoichiometric ratio of TiCx nanoparticles. Finally, morphologies with specific exposed crystal planes in the Al melt can be effectively designed and manipulated for various applications. Keywords: TiCx nanoparticles, Stoichiometric ratio, Al/TiCx interface, Growth mechanisms, Morphology evolution manipulation

Circular RNA (circRNA) is a type of non-coding RNA molecule that affects the cellular regulatory network by sequestering microRNA (miRNA) like a sponge. This study was performed to identify differentially-expressed circRNA in oral squamous cell carcinomas (OSCCs). By high-throughput sequencing, microarray circRNA expression profiles were acquired from patients with OSCCs (n = 8) and controls (n = 8), which totaled 1921 existing circRNA molecules and 10021 novel circRNA molecules. Most of the circular RNA is from exons and distributed in the No. 1 and 2 chromosomes. Eight up-regulated and down-regulated circRNA molecules were identified as differentially-expressed in OSCCs. Among this, the expression of circ_000334, circ_006740, and circ_006371 are significantly down-regulated in 42 pairs of samples, which means that these circRNA molecules might be implicated in oncogenesis and development of OSCCs.

YM155, a small molecule inhibitor of survivin, has been studied in many tumors. It has been shown that YM155 inhibited oral squamous cell carcinoma through promoting apoptosis and autophagy and inhibiting proliferation. It was found that YM155 also inhibited the oral squamous cell carcinoma–mediated angiogenesis through the inactivation of the mammalian target of rapamycin pathway. Rapamycin, a mammalian target of rapamycin inhibitor, played an important role in the proliferation and angiogenesis of oral squamous cell carcinoma cell lines. In our study, cell proliferation assay, transwell assay, tube formation assay, and western blot assay were used to investigate the synergistic effect of rapamycin on YM155 in oral squamous cell carcinoma. Either in vitro or in vivo, rapamycin and YM155 exerted a synergistic effect on the inhibition of survivin and vascular endothelial growth factor through mammalian target of rapamycin pathway. Overall, our results revealed that low-dose rapamycin strongly promoted the sensitivity of oral squamous cell carcinoma cell lines to YM155.

Aiming at the application layer distributed deny of service(App-DDoS) attacks, a K-means multiple principal component analysis algorithm(KMPCAA) utilizing the Web log mining was proposed, then an App-DDoS detection method based on KMPCAA was presented. Firstly, a statistical properties feature extracting method was designed by ana-lyzing the difference between normal users' and attackers' access behavior. Secondly, a k-means multiple principal com-ponent analysis algorithm was proposed by using the maximum distance classification method according to the data di-mension reduction property of the principal component analysis, and then the testing model based on the algorithm was established. Finally, an App-DDoS attack detection experiment on the CTI-DATA dataset and the simulated attack data-set was conducted. In this experiment, the proposed method was compared with the fuzzy synthetical evaluation (FSE) algorithm, the hidden semi-Markov model (HsMM) detection algorithm and the dempster-shafer evidence theory (D-S) algorithm. Experimental results demonstrate that the KMPCAA detection algorithm has better detection performance.

Invasive plants are a huge burden on the environment, and modify local ecosystems by affecting the indigenous biodiversity. Invasive plants are generally less affected by pathogens, although the underlying molecular mechanisms responsible for their enhanced resistance are unknown. We investigated expression profiles of three defense hormones (salicylic acid, jasmonic acid, and ethylene) and their associated genes in the invasive weed, Alternanthera philoxeroides, and its native congener, A. sessilis, after inoculation with Rhizoctonia solani. Pathogenicity tests showed significantly slower disease progression in A. philoxeroides compared to A. sessilis. Expression analyses revealed jasmonic acid (JA) and ethylene (ET) expressions were differentially regulated between A. philoxeroides and A. sessilis, with the former having prominent antagonistic cross-talk between salicylic acid (SA) and JA, and the latter showing weak or no cross-talk during disease development. We also found that JA levels decreased and SA levels increased during disease development in A. philoxeroides. Variations in hormonal gene expression between the invasive and native species (including interspecific differences in the strength of antagonistic cross-talk) were identified during R. solani pathogenesis. Thus, plant hormones and their cross-talk signaling may improve the resistance of invasive A. philoxeroides to pathogens, which has implications for other invasive species during the invasion process.

It is widely known that the special performances and extensive applications of the nanoscale materials are determined by their as-synthesized structures, especially their growth sizes and morphologies. Hereinto, titanium carbides, which show brilliant comprehensive properties, have attracted considerable attention from researchers. How to give full play to their potentials in the light-weight manufacture, microwave absorption, electromagnetic protection, energy conversion and catalyst areas has been widely studied. In this summarized article, the synthesis methods and mechanisms, corresponding growth morphologies of titanium carbides and their further applications were briefly reviewed and analyzed according to their different morphological dimensions, including one-dimensional nanostructures, two-dimensional nanosheets and three-dimensional nanoparticles. It is believed that through the investigation of the crystal structures, synthesis methods, growth mechanisms, and morphology characterizations of those titanium carbides, new lights could be shed on the regulation and control of the ceramic phase specific morphologies to meet with their excellent properties and applications. In addition, the corresponding development prospects and challenges of titanium carbides with various growth morphologies were also summarized.

Aiming at the problems of security assessment in XML communication protocols, a novel three-dimensional spherical model based protocol security evaluation method was proposed. Firstly, a three-dimensional security evaluation index system was constructed through positions of indexes on the spherical shell. Secondly, by using the coordinate's projection area as a measure criterion, evaluation indexes' weights of the first level and the second level were obtained with the analytic hierarchy process (AHP), the sphere and the sector angle. Thirdly, security components values of XML communication protocol were calculated in the aspects of XML's content, communication load and security vulne-rability. Finally, the security evaluation result of XML communication protocol was achieved through quantization calcu-lation and further comprehensive analysis. Experimental results show that this method is competent for the protocol secu-rity evaluation and meets security evaluating requirem L communication protocols effectively.

Simultaneously improving the strength, toughness, and ductility of cast steels has always been a difficult problem for researchers. Biphase TiCx-TiB2 nanoparticle-reinforced cast steels are prepared by adding in situ nanosized biphase TiCx-TiB2/Al master alloy during the casting process. The experimental results show that a series of significant changes take place in the microstructure of the steel: the ferrite-pearlite structure of the as-cast steels and the bainite structure of the steels after heat treatment are refined, the grain size is reduced, and the content of nanoparticles is increased. Promotion of nucleation and inhibition of dendrite growth by biphase TiCx-TiB2 nanoparticles leads to a refinement of the microstructure. The fine microstructure with evenly dispersed nanoparticles offers better properties [yield strength (1246 MPa), tensile strength (1469 MPa), fracture strain (9.4%), impact toughness (20.3 J/cm2) and hardness (41 HRC)] for the steel with 0.018 wt.% biphase TiCx-TiB2 nanoparticles, which are increased by 15.4%, 31.2%, 4.4%, 11.5%, and 7.9% compared with the 40Cr steels. The higher content of nanoparticles provides higher strengths and hardness of the steel but are detrimental to ductility. The improved properties may be attributed to fine grain strengthening and the pinning effect of nanosized carbide on dislocations and grain boundaries. Through this work, it is known that the method of adding trace (0.018 wt.%) biphase TiCx-TiB2 nanoparticles during casting process can simultaneously improve the strength, toughness, as well as ductility of the cast steel.

Motivated by the recent discovery of a spin-liquid phase for the Hubbard model on the honeycomb lattice at half-filling (Meng et al 2010 Nature 88 487), we apply both perturbative and non-perturbative techniques to derive effective spin Hamiltonians describing the low-energy physics of the Mott-insulating phase of the system. Exact diagonalizations of the so-derived models on small clusters are performed, in order to assess the quality of the effective low-energy theory in the spin-liquid regime. We show that six-spin interactions on the elementary loop of the honeycomb lattice are the dominant sub-leading effective couplings. A minimal spin model is shown to reproduce most of the energetic properties of the Hubbard model on the honeycomb lattice in its spin-liquid phase. Surprisingly, a more elaborate effective low-energy spin model obtained by a systematic graph expansion rather disagrees beyond a certain point with the numerical results for the Hubbard model at intermediate couplings.

In order to effectively reduce energy consumption and increase range mile, new energy vehicles represented by Tesla have greatly aroused the application of integrated magnesium (Mg) alloy die casting technology in automobiles. Previously, the application of Mg alloys in automobiles, especially in automotive cockpit components, is quite extensive, while it has almost disappeared for a period of time due to its relatively high cost, causing a certain degree of information loss in the application technology of Mg alloy parts in automobiles. The rapid development of automotive technology has led to a higher requirement for the automotive components compared with those traditional one. Therefore, whatever the components themselves, or the Mg alloy materials and die casting process have to face an increasing challenge, needing to be upgraded. In addition, owing to its high integration characteristics, the application of Mg alloy die casting technology in large-sized and thin-walled automotive parts has inherent advantages and needs to be expanded urgently. Indeed, it necessitates exploring advance Mg alloys and new product structures and optimizing die casting processes. This article summarizes and analyzes the development status of thin-walled and large-sized die casting Mg alloy parts in passenger car cockpit and corresponding material selection methods, die casting processes as well as mold design techniques. Furthermore, this work will aid researchers in establishing a comprehensive understanding of the manufacture of thin-walled and large-sized die casting Mg alloy parts in automobile cockpit. It will also assist them in developing new Mg alloys with improved comprehensive performance and new processes to meet the high requirements for die casting automotive components. [ABSTRACT FROM AUTHOR]