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Deep learning algorithm emerges as a new method to take the raw features from large dataset and mine their deep implicit relations, which is promising for solving traditional physical challenges. A particularly intricate and difficult challenge is the energy loss mechanism of energetic ions in solid, where accurate prediction of stopping power is a long-time problem. In this work, we develop a deep-learning-based stopping power model with high overall accuracy, and overcome the long-standing deficiency of the existing classical models by improving the predictive accuracy of stopping power for ultra-heavy ion with low energy, and the corresponding projected range. This electronic stopping power model, based on deep learning algorithm, could be hopefully applied for the study of ion-solid interaction mechanism and enormous relevant applications.

Background and Purpose: The benefit of endovascular treatment (EVT) for large vessel occlusion in clinical practice in developing countries like China needs to be confirmed. The aim of the study was to determine whether the benefit of EVT for acute ischemic stroke in randomized trials could be generalized to clinical practice in Chinese population. Methods: We conducted a prospective registry of EVT at 111 centers in China. Patients with acute ischemic stroke caused by imaging-confirmed intracranial large vessel occlusion and receiving EVT were included. The primary outcome was functional independence at 90 days defined as a modified Rankin Scale score of 0 to 2. Outcomes of specific subgroups in the anterior circulation were reported and logistic regression was performed to predict the primary outcome. Results: Among the 1793 enrolled patients, 1396 (77.9%) had anterior circulation large vessel occlusion (median age, 66 [56–73] years) and 397 (22.1%) had posterior circulation large vessel occlusion (median age, 64 [55–72] years). Functional independence at 90 days was reached in 45% and 44% in anterior and posterior circulation groups, respectively. For anterior circulation population, underlying intracranial atherosclerotic disease was identified in 29% of patients, with higher functional independence at 90 days (52% versus 44%; P =0.0122) than patients without intracranial atherosclerotic disease. In the anterior circulation population, after adjusting for baseline characteristics, procedure details, and early outcomes, the independent predictors for functional independence at 90 days were age 6 hours (OR, 1.536 [95% CI, 1.065–2.216]), local anesthesia (OR, 2.194 [95% CI, 1.325–3.633]), final modified Thrombolysis in Cerebral Infarction 2b/3 (OR, 2.052 [95% CI, 1.085–3.878]), puncture-to-reperfusion time ≤1.5 hours (OR, 1.628 [95% CI, 1.098–2.413]), and National Institutes of Health Stroke Scale score 24 hours after the procedure Conclusions: Despite distinct characteristics in the Chinese population, favorable outcome of EVT can be achieved in clinical practice in China. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03370939.

Vascular calcification was an independent risk of cardiovascular and cerebrovascular diseases (CCDs). Studies reported that conditioned media of choroid plexus epithelium cells (CPECs-CM) showed potential neuroprotective effects. However, the protective effect of CPECs-CM against vascular calcification (VC) has not been reported yet. Herein, high phosphate (HPi)–induced calcification model in mouse aortic vascular smooth muscle cells (MOVAS) was established, and the protective effects and underlying mechanism of CPECs-CM against HPi-induced calcification were explored. The results indicated that CPEC cells were successfully isolated and cultured, and CPECs-CM co-treatment significantly inhibited HPi-induced calcification of MOVAS cells through blocking alkaline phosphatase activity and expression. CPECs-CM co-treatment also suppressed reactive oxide species–mediated DNA damage in HPi-treated MOVAS cells. Moreover, dysfunction of MAPKs and PI3K/AKT pathways both contributed to HPi-induced calcification of MOVAS cells, and CPECs-CM co-treatment attenuated HPi-induced calcification by normalizing MAPKs and PI3K/AKT expression. Taken together, our findings provide evidence that CPECs-CM had the potential to inhibit vascular calcification with potent application in chemoprevention and chemotherapy of human CCD.

BackgroundRedundancy is a common feature of genomes, presumably to ensure robust growth under different and changing conditions. Genome compaction, removing sequences nonessential for given conditions, provides a novel way to understand the core principles of life. The synthetic chromosome rearrangement and modification by loxP-mediated evolution (SCRaMbLE) system is a unique feature implanted in the synthetic yeast genome (Sc2.0), which is proposed as an effective tool for genome minimization. As the Sc2.0 project is nearing its completion, we have begun to explore the application of the SCRaMbLE system in genome compaction.ResultsWe develop a method termed SCRaMbLE-based genome compaction (SGC) and demonstrate that a synthetic chromosome arm (synXIIL) can be efficiently reduced. The pre-introduced episomal essential gene array significantly enhances the compacting ability of SGC, not only by enabling the deletion of nonessential genes located in essential gene containing loxPsym units but also by allowing more chromosomal sequences to be removed in a single SGC process. Further compaction is achieved through iterative SGC, revealing that at least 39 out of 65 nonessential genes in synXIIL can be removed collectively without affecting cell viability at 30 °C in rich medium. Approximately 40% of the synthetic sequence, encoding 28 genes, is found to be dispensable for cell growth at 30 °C in rich medium and several genes whose functions are needed under specified conditions are identified.ConclusionsWe develop iterative SGC with the aid of eArray as a generic yet effective tool to compact the synthetic yeast genome.

Additional file 6. Review history.

Additional file 1: Fig. S1. Map of synXIIL. Fig. S2. Gene number and size of each loxPsym unit of synXIIL. Fig. S3. Map of the Cre plasmid used in this study. Fig. S4. An example of PCRtag analysis. Fig. S5. Stability of URA3 integrated in synXIIL without the expression of Cre. Fig. S6. Genome rearrangements in ZLY294-ZLY298. Fig. S7. Genome rearrangements in ZLY299-ZLY303. Fig. S8. PCRtag analysis of SCRaMbLEd strains with or without URA3 integration and 5-FOA selection. Fig. S9. The assembly and verification of eArray. Fig. S10. PCRtag analysis to confirm the deletion of LU-20. Fig. S11. The deletion boundary reflects the 3D proximity of loxPsym sites. Fig. S12. Genome rearrangements in iterative SGC strains. Fig. S13. The growth of SGC strains on YPD 30 °C. Fig. S14. Competition among synXIIL, BY4742 and eArray strain with single essential gene deletion.

Background: Whether thoracic radiotherapy (TRT) could be applied to interstitial lung diseases and lung cancer(ILD-LC) patients safely remains unclear. This retrospective study aims to evaluate the efficacy and safety of definitive TRT in locally advanced non-small cell lung cancer (LA-NSCLC) patients with pre-existing ILD, and to analyze the associated risk factors for radiation induced lung toxicities (RILTs) in the clinical setting. Methods: Patients with histologically confirmed LA-NSCLC and pre-existing ILD treated definitive TRT between 2010 and 2019 were retrospectively reviewed. Patient, tumor, and treatment characteristics were evaluated to determine the risk factors for RILTs. Pre-radiation CT of all patients were reviewed by two radiologists and one pulmonologist and are scored according to Muller’s thin-section CT scoring system for IPF: 0-no discrete honeycombing, with interlobular septal thickening; 1-honeycombing involving 0-5% of the lobe; 2-honeycombing 6-24%; 3-honeycombing 25-49%; 4-honeycombing 50-74%;5-honeycombing >75%. Univariate and multivariate analyses with logistic regression models and cox proportional hazards approach were performed to identify the risk factor(s) of RILTs and overall survival(OS) respectively. Findings: Among 1261 LA-NSCLC patients, 85 were found with pre-existing ILD and enrolled in the analysis. 36·5% of them were scored more than 1 point on CT. 20% patients developed G3+ RILTs within 1 year after the last irradiation, with remarkably 11·8% dying from lung toxicities. And the incidence of symptomatic (G3+) RILTs abruptly dropped to 11·1%(6/54),3·8%(1/26),and 0%(0/19)for patients with CT score≤1, V20 1 and V20≥20% were independently associated with higher risk of G3+ RILTs. The median OS and PFS were 14·0 months and 7·4 month respectively. In the univariate analysis for OS, clinical stage and G3+RILT were evaluated as risk factors while patients in low-risk group, defined as honeycombing score1 and V20≥20% were significantly associated with high incidence of severe lung toxicities, leading to poor survival. However, patients at low risk might benefit from TRT with a considerable overall survival. Funding: None to declare Declaration of Interest: None to declare. Ethical Approval: The study was approved by the institutional review board of National Cancer Center, Chinese Academy of Medical Sciences and Peking Union Medical College (IRB No·NCC2612).

The trusted execution environment (TEE) is the security basis of embedded systems, which can provide a hardware-based isolated execution environment for security-sensitive components. Isolation of memory is a critical mechanism of TEE, the security of which plays a very important role in TEE's construction. In this paper, we present a formal verification of security properties about the memory isolation mechanism of TEE systems based on the ARM TrustZone, which is a hardware security technology commonly used on billions of ARM processors to create TEE. We establish a formal model of memory isolation, which consists of the formalization of ARMv8 architecture hardware components related to memory isolation and the formalization of a TrustZone monitor supporting world switch. We formally explicit and verify the correctness properties of memory management along with the information flow security properties of the memory isolation mechanism. The formalizations and verifications are all performed in the interactive theorem prover Isabelle/HOL.

A major challenge for future nuclear reactors is to design nuclear materials that can sustain extremely prolonged radiation damage. Local lattice distortion, considered as a core effect of high-entropy alloys (HEAs), can suppress the growth of radiation defects to control radiation performance. However, local lattice distortion in HEAs is rarely quantitatively measured. Here we employed total scattering technique to study the local structure of the face-centered cubic (fcc) equiatomic FeCoNiCr MEA, and FeCoNiCrMn and FeCoNiCrPd HEAs before and after ion irradiation. Their local lattice distortions were quantitatively evaluated based on the difference of lattice constant between the local structure and the average structure. We revealed that the mean local lattice distortion in the pristine samples varies in the following order: FeCoNiCr

A defining goal of synthetic biology is to develop biomaterials with superior performance and versatility. Here we introduce a purely genetically encoded and self-assembling biopolymer based on the SpyTag-SpyCatcher chemistry. We show the application of this polymer for highly efficient uranyl binding and extraction from aqueous solutions, by embedding two functional modules-the superuranyl binding protein and the monomeric streptavidin-to the polymer via genetic fusion. We further provide a modeling strategy for predicting the polymer's physical properties, and experimentally demonstrate the autosecretion of component monomers from bacterial cells. The potential of multifunctionalization, in conjunction with the genetic design and production pipeline, underscores the advantage of the SpyTag-SpyCatcher biopolymers for applications beyond trace metal enrichment and environmental remediation.

Single-phase concentrated solid solution alloys (SP-CSAs) are newly emerging advanced structural materials, which are defined as multiprincipal element solid solutions. SP-CSAs with more than four components in equimolar or near-equimolar ratios are also referred to as high-entropy alloys due to their high configurational entropy. SP-CSAs are potential structural materials in advanced nuclear energy systems due to their attractive mechanical properties. Therefore many investigations have been carried out to study the irradiation-induced structural damage and defect behavior in SP-CSAs. This paper reviews recent experimental results on the irradiation responses of various SP-CSAs, focusing on the accumulation of irradiation-induced structural damage, void swelling resistance, and solute segregation behavior. In addition, the characteristic defect behavior in SP-CSAs derived from ab initio and molecular dynamics simulations, as well as the challenges in the applications of SP-CSAs for the nuclear energy systems are briefly discussed.

With the rise of Internet of Things (IoT) and Cyber-Physical Systems (CPS), the need for smart embedded devices is rapidly increasing, and so does the security and privacy risk. This paper focuses on enabling both remote attestation and authentication of current commodity low-resource embedded devices to enhance security in the IoT and CPS contexts. We demonstrate a detailed design and prototype implementation of AAoT, a lightweight and practical mechanism for Attestation and Authentication of Things, that can provide software integrity, mutual authentication and tamper-proof feature for smart embedded devices. AAoT is based on physical unclonable functions (PUFs), random memory filling and software attestation without requiring any changes in existing micro-controller units (MCUs). We show how to obtain efficient implementations and optimizations for each of the building blocks of AAoT, including a PUF-based memory filling, a checksum function with block-based traversal, a pseudorandom function, a reverse fuzzy extractor and a random number generator. The prototype is implemented on a low-end MCU platform (TI MSP430) by using onboard SRAM, registers and Flash resources.

Using first-principles calculations based on density-functional theory, the energetics of different vacancy-type defects, including voids, stacking fault tetrahedra (SFT) and vacancy loops, in Ni are investigated. It is found that voids are more stable than SFT at 0 K, which is also the case after taking into account the volumetric strains. By carrying out ab initio molecular dynamics simulations at temperatures up to 1000 K, direct transformations from vacancy loops and voids into SFT are observed. Our results suggest the importance of temperature effects in determining thermodynamic stability of vacancy clusters in face-centered cubic metals.

Multi-component alloys, e.g., high-entropy alloys, exhibit excellent mechanical and radiation tolerance properties, making them potential candidate materials in nuclear applications. In this work, the void swelling in a single-phase body-centered cubic (bcc) reduced activation multi-component alloy FeCrV under high dose Au-ion irradiation was investigated. It is found that FeCrV has a significantly suppressed void swelling compared to α-Fe, with voids of smaller size distributed in a narrower region. To understand the difference between these two alloys in the defect evolution and its possible effect on the void swelling, the diffusion of point defects in α-Fe and FeCrV was investigated. Combined Density Functional Theory (DFT) and kinetic Monto Carlo (kMC) method based on the environment-dependent vacancy migration energies was used to simulate the vacancy diffusion. It is shown that vacancy diffusion is enhanced, which is because vacancies prefer to migrate through the easy migration channels which have lower values of the wide migration energy distribution in multi-component alloys. Ab initio molecular dynamics (AIMD) was employed to simulate the interstitial diffusion. The results show the interstitial diffusion is sluggish in FeCrV due to the atomic traps existing that slow down interstitials’ migration. The migration process of point defects in bcc multi-component alloy shows clear chemical environment dependence. The closer mobilities of vacancies and interstitials enhance the local recombination of point defects and suppress the void swelling.

Single-phase concentrated solid-solution alloys (SP-CSSAs) have shown great potential as structural materials in advanced reactor systems. Up to date, nevertheless, the synergistic effect of compositional complexity and irradiation temperature on helium (He) irradiation-induced cavity formation has not been systematically studied yet. In this work, pure Ni and three prototype face-centered-cubic SP-CSSAs, i.e., NiCo, NiCoCr and NiCoFeCrMn, were irradiated with He+ ions at 673, 773, 873 and 973 K. The evolution of He-induced cavities were investigated in detail with transmission electron microscopy. It was found that growth of He cavities was suppressed with increasing compositional complexity at 673 and 773 K. Due to the lower melting temperature, NiCoFeCrMn exhibited the strongest temperature susceptibility in terms of He cavity growth with the increasing temperature. Interestingly, the He cavity growth tended to be enhanced with increasing compositional complexity when the radiation temperature increaseed to 973 K, which can be attributed to the prominent chemical-biased vacancy migration at high temperatures.

The way in which defects interact with grain boundaries (GBs) has profound influences on materials performance. In this work, we study defect-GBs interactions in a model CuNiCoFe high-entropy alloy (HEA) based on atomistic simulations. Five representative GBs are considered, namely Σ3 {11−1} coherent twin GB, Σ5 {010} twist GB, Σ11 {113} symmetric tilt GB (STGB), Σ11 {554} asymmetric tilt GB (ATGB), and Σ45 {001} tilt GB. A particular focus is placed on the role of chemical disorder and local elemental segregation in influencing the defect-GBs interactions. Specifically, we compare the results obtained within an averaged atom model, the random HEA with randomly distributed elements, and the equilibrated HEA with Cu segregation after a combined Monte-Carlo/Molecular statics algorithm. For the pristine CuNiCoFe HEA without GBs, we find chemical occupancy fluctuations tend to lower the formation energies of defects, especially for interstitials because of the larger lattice distortion. For defect-GBs interactions, we find GBs strongly interact with interstitials over vacancies. We further reveal that elemental segregation can enhance the sink strength of GBs towards vacancies, but at the same time, reduce the sink strength toward interstitials. Therefore, the bias effects of GBs toward interstitials and vacancies are suppressed in HEAs due to local ordering, promoting efficient defect annihilation within the grain interiors. We highlight that the local ordering tendency and elemental segregation in HEAs play dominant roles in influencing the defect-GB interactions.

Refractory multiple principal elemental alloys (MPEAs) hold great promise for structural materials in future nuclear energy systems. Compared to the extensively studied face-centered cubic (FCC) MPEAs, the irradiation resistance of body-centered cubic (BCC) refractory MPEAs is relatively less known. In this work, we study defect accumulation and evolution in two BCC VTaTi and VTaW MPEAs comparatively through atomistic simulations. For this purpose, we have parameterized the Embedded Atom Method (EAM) potential parameters for V metals. Combined with available potential parameters for other elements, we construct average atom models for the considered alloys to elucidate the effects of chemical complexities in BCC MPEAs. Our results based on Frenkel pair accumulation simulations suggest that the major influence of chemical fluctuations in BCC MPEAs is on the clustering behavior of defects, which leads to discrete point defects or small defect clusters, in contrast to the large defect clusters observed in the average atom model. We further show that the diffusion of interstitial clusters exhibits different modes due to chemical complexity. While interstitials show either three-dimensional or one-dimensional diffusion in the average atom model, the mean free path of interstitials in the random alloy is strongly suppressed. These results provide fundamental insights into the irradiation response of BCC MPEAs and pinpoint the critical role of chemical complexity on defect evolution, which lay the basis for the future development of irradiation-resistant structural materials based on BCC MPEAs.

Multicomponent high-entropy alloys (HEAs) with compositionally disordered elemental arrangement have attracted extensive attention because of their excellent mechanical properties. However, these alloys usually exhibit low strength at elevated temperatures. Recent works suggest that HEAs strengthened by L12 ordered intermetallics of the Ni3Al type possess a superior synergy of strength and ductility. The performance of such ordered-intermetallics-strengthened HEAs depends critically on the composition and deformation mechanism of the strengthening component, which will inevitably suffer partial disorder in HEAs. In this work, we study the elemental partitions and deformation mechanisms in typical multicomponent intermetallics (MCIs) based on density functional theory (DFT) calculations. Informed by experiments, systems considered in this work include L12-type (Ni,Co,Fe)3(Al,Ti,Fe) and its six derived subsystems. We first determine the site preference of different elements in MCIs using Monte-Carlo simulations with the energies obtained from DFT calculations (DFT-MC). The results confirm that Ti prefers Al sites. In contrast, most Co and Fe atoms tend to occupy Ni sublattice. With the established elemental occupations, we build quasirandom structures with partial disorders in either or both sublattices of the L12 structures. DFT results show that incorporation of Ti in the Al sublattice dominates the increase of stable planar fault energies (γSPF) in the considered MCIs. In contrast, Co in the Ni sublattice decreases the energy cost for planar fault formation. We further uncover quantitative relations between γSPF and geometrical structures as well as electronic structures in MCIs. The analytical results show that the incorporation of Ti decreases the adaptability of (Ni,Co,Fe)3(Al,Ti,Fe) both geometrically and electronically. Specifically, we propose that γSPF can be described by the ability of the alloy to accommodate planar faults, which is measured by the interlayer spacing changes between {111} planes [Δd(111)] and charge density redistribution (Δρ) at critical points (cps). We address the fundamental understandings of the deformation behavior of MCIs by pinpointing the contributions of different species to their local geometrical and electronic structures, which pave the way for rationally designing ordered-precipitate-strengthened HEAs.

Interaction of energetic ions or lasers with solids often induces electronic excitations that may modify material properties significantly. In this study, effects of electronic excitations on stron...

We report the stacking fault energy (SFE) for a series of face-centered cubic ( fcc ) equiatomic concentrated solid solution alloys (CSAs) derived as subsystems from the NiCoFeCrMn and NiCoFeCrPd high entropy alloys based on ab initio calculations. At low temperatures, these CSAs display very low even negative SFEs, indicating that hexagonal close-pack ( hcp ) is more energy favorable than fcc structure. The temperature dependence of SFE for some CSAs is studied. With increasing temperature, a hcp -to- fcc transition is revealed for those CSAs with negative SFEs, which can be attributed to the role of intrinsic vibrational entropy. The analysis of the vibrational modes suggests that the vibrational entropy arises from the high frequency states in the hcp structure that originate from local vibrational mode. Our results underscore the importance of vibrational entropy in determining the temperature dependence of SFE for CSAs.

Recently developed concentrated solid solution alloys (CSAs) are shown to have improved performance under irradiation that depends strongly on the number of alloying elements, alloying species, and their concentrations. In contrast to conventional dilute alloys, CSAs are composed of multiple principal elements situated randomly in a simple crystalline lattice. As a result, the intrinsic disorder has a profound influence on energy dissipation pathways and defect evolution when these CSAs are subjected to energetic particle irradiation. Extraordinary irradiation resistance, including suppression of void formation by two orders of magnitude at an elevated temperature, has been achieved with increasing compositional complexity in CSAs. Unfortunately, the loss of translational invariance associated with the intrinsic chemical disorder poses great challenges to theoretical modeling at the electronic and atomic levels. Based on recent computer simulation results for a set of novel Ni-containing, face-centered cubic CSAs, we review theoretical modeling progress in handling disorder in CSAs and underscore the impact of disorder on defect dynamics. We emphasize in particular the unique challenges associated with the description of defect dynamics in CSAs.

The damage production induced by MeV highly charged ions (HCI) irradiations in graphene supported on a SiO 2 substrate is investigated using molecular dynamics method. We get results in agreement with our recent experiments. We find that the electronic energy loss and potential energy deposition have similar effects on the defects creation in SiO 2 substrate-supported graphene and both mechanisms of energy deposition seem to contribute in an additive way. The influences of the energy deposition depth and radius are studied. Only the energy deposited below the surface within 2.5 nm will induce the damage in graphene. Hence, the HCI can be a powerful tool to induce defects in graphene without causing deep damage of the substrate. When charge of incident Xe q + is above 30, a nanopore is formed and the size of nanopore in graphene can be controlled by changing the incident charge state.

Single-phase concentrated solid solution alloys, including high entropy alloys, exhibit remarkable mechanical properties as well as extraordinary corrosion and radiation resistance compared to pure metals and dilute alloys. However, the mechanisms responsible for these properties are unknown in many cases. In this work, we employ ab initio molecular dynamics based on density functional theory to study the diffusion of interstitial atoms in Ni and Ni-based face-centered cubic concentrated alloys including NiFe, NiCo and NiCoCr. We model the defect trajectories over 100 ps and estimate the tracer diffusion coefficients, correlation factors and activation energies. We find that the diffusion mass transport in concentrated alloys is not only slower than that in pure components, i.e. sluggish diffusion, but also chemically non-homogeneous. The results obtained here can be used to understand and predict atomic segregation and phase separation in concentrated solid solution alloys under irradiation.

Catalytic amounts of TBHP (15 mol%) promoted tribromomethylation of activated alkenes has been developed. This method provided a metal-free aerobic way to construct tribromomethylated 2-oxindoles from the reaction of readily available N-arylacrylamides with CBr4via a proposed tandem radical cyclization process. Air is used as an efficient terminal oxidant in this transformation. The formation of 1,1-dibromoolefin derivatives was also realized at higher temperature under neat conditions.

A simple and practical carbon tetrabromide promoted intramolecular aerobic oxidative dehydrogenative coupling reaction has been developed to provide a straightforward ring closure protocol for 2-aryloxybenzaldehydes to furnish xanthones. The reaction was performed under metal-, additive- and solvent-free conditions with good tolerance of functional groups. The present method is also applicable to the synthesis of fluorenones by using 2-arylbenzaldehydes as substrates. Preliminary studies of the reaction mechanism indicated that the reaction may proceed through a radical pathway.

Secure enclaves provide a practical solution to secure computation, and current approaches to secure enclaves are implemented by extending hardware security mechanisms to the CPU architecture. Therefore, it is hard for a platform to offer secure computation if its CPU architecture is not equipped with any secure enclave features. Unfortunately, ARM CPUs, dominating mobile devices and having increasing momentum in cloud markets, do not provide any security mechanisms achieving the security equivalent to modern secure enclave architectures. In this paper, we propose SecTEE, a software-based secure enclave architecture which is based on the CPU's isolation mechanism and does not require specialized security hardware of the CPU architecture such as memory encryption engines. SecTEE achieves a high level of security even compared with hardware-based secure enclave architectures: resistance to privileged host software attacks, lightweight physical attacks, and memory access based side-channel attacks. Besides, SecTEE provides rich trusted computing primitives for enclaves: integrity measurement, remote attestation, data sealing, secrets provisioning, and life cycle management. We implement a SecTEE prototype based on the ARM TrustZone technology, but our approach can be applied to other CPU architectures with isolation mechanisms. The evaluation results show that most overhead comes from the software encryption and the runtime overhead imposed by trusted computing primitives is acceptable.

The interaction between point defects and dislocations plays a crucial role in governing material properties and microstructural evolutions under external stimuli, such as mechanical deformation and irradiation. Here, we present an atomistic study of the interactions between point defects and dislocations in concentrated solid-solution alloys (CSAs). Using molecular statics and kinetic Monte Carlo methods, we demonstrate that the strain energy and stress field distribution induced by a dislocation in CSAs are highly inhomogeneous along the dislocation line, which leads to heterogeneity of defect-dislocation interactions. Specifically, the interactions are spatially different and screened by the random arrangement of different elemental species. Such localization of defect-dislocation interaction indicates that the ``dislocation-bias'' mechanism that is a driving force for radiation-induced void swelling can be suppressed in concentrated alloys.

Whereas exceptional mechanical and radiation performances have been found in the emergent medium- and high-entropy alloys (MEAs and HEAs), the importance of their complex atomic environment, reflecting diversity in atomic size and chemistry, to defect transport has been largely unexplored at the atomic level. Here we adopt a local structure approach based on the atomic pair distribution function measurements in combination with density functional theory calculations to investigate a series of body-centered cubic (BCC) MEAs and HEAs. Our results demonstrate that all alloys exhibit local lattice distortions (LLD) to some extent, but an anomalous LLD, merging of the first and second atomic shells, occurs only in the Zr- and/or Hf-containing MEAs and HEAs. In addition, through the ab-initio simulations we show that charge transfer among the elements profoundly reduce the size mismatch effect. The observed competitive coexistence between LLD and charge transfer not only demonstrates the importance of the electronic effects on the local environments in MEAs and HEAs, but also provides new perspectives to in-depth understanding of the complicated defect transport in these alloys., Comment: 5 figures, 2 tables

Remote attestation is a very important mechanism helping a trusted party to get the status of a remote embedded device. Most remote attestation schemes aim at checking the code integrity and leave devices vulnerable to runtime attacks. Recently a new kind of attestation called control flow attestation has been proposed to get rid of this limitation. However, previous studies on control flow attestation cannot verify the attestation result efficiently and lack secure storage.

The development of the Internet of Things has made embedded devices widely used. Embedded devices are often used to process sensitive data, making them the target of attackers. ARM TrustZone technology is used to protect embedded device data from compromised operating systems and applications. But as the value of the data stored in embedded devices increases, more and more effective physical attacks have emerged. However, TrustZone cannot resist physical attacks. We propose SoftME, an approach that utilizes the on-chip memory space to provide a trusted execution environment for sensitive applications. We protect the confidentiality and integrity of the data stored on the off-chip memory. In addition, we design task scheduling in the encryption process. We implement a prototype system of our approach on the development board supporting TrustZone and evaluate the overhead of our approach. The experimental results show that our approach improves the security of the system, and there is no significant increase in system overhead.

ARM TrustZone technology is widely used to provide Trusted Execution Environments (TEE) for mobile devices. However, most TEE OSes are implemented as monolithic kernels. In such designs, device drivers, kernel services and kernel modules all run in the kernel, which results in large size of the kernel. It is difficult to guarantee that all components of the kernel have no security vulnerabilities in the monolithic kernel architecture, such as the integer overflow vulnerability in Qualcomm QSEE TrustZone and the TZDriver vulnerability in HUAWEI Hisilicon TEE architecture. This paper presents MicroTEE, a TEE OS based on the microkernel architecture. In MicroTEE, the microkernel provides strong isolation for TEE OS's basic services, such as crypto service and platform key management service. The kernel is only responsible for providing core services such as address space management, thread management, and inter-process communication. Other fundamental services, such as crypto service and platform key management service are implemented as applications at the user layer. Crypto Services and Key Management are used to provide Trusted Applications (TAs) with sensitive information encryption, data signing, and platform attestation functions. Our design avoids the compromise of the whole TEE OS if only one kernel service is vulnerable. A monitor has also been added to perform the switch between the secure world and the normal world. Finally, we implemented a MicroTEE prototype on the Freescale i.MX6Q Sabre Lite development board and tested its performance. Evaluation results show that the performance of cryptographic operations in MicroTEE is better than it in Linux when the size of data is small., Comment: 8 pages, 8 figures

Concentrated solid-solution alloys (CSAs) have demonstrated promising irradiation resistance depending on their compositions. Under irradiation, various defects can be produced. One of the most important parameters characterizing the defect production and the resulting defect number is the threshold displacement energies (E d). In this work, we report the results of E d values in a series of Ni–Fe–Cr concentrated solid solution alloys through molecular dynamics (MD) simulations. Based on several different empirical potentials, we show that the differences in the E d values and its angular dependence are mainly due to the stiffness of the potential in the intermediate regime. The influences of different alloying elements and temperatures on E d values in different CSAs are further evaluated by calculating the defect production probabilities. Our results suggest a limited influence of alloying elements and temperature on E d values in concentrated alloys. Finally, we discuss the relationship between the primary damage and E d values in different alloys. Overall, this work presents a thorough study on the E d values in concentrated alloys, including the influence of empirical potentials, their angular dependence, temperature dependence, and effects on primary defect production.

Background To develop and validate a fully automated deep learning-based segmentation algorithm to segment pulmonary lobe on low-dose computed tomography (LDCT) images. Methods This study presents an automatic segmentation of pulmonary lobes using a fully convolutional neural network named dense V-network (DenseVNet) on lung cancer screening LDCT images. A total of 160 LDCT cases for lung cancer screening (100 in the training set, 10 in the validation set, and 50 in the test set) was included in this study. Specifically, the template of pulmonary lobes (the right lung consists of three lobes, and the left lung consists of two lobes) were obtained from pixel-level annotations by semiautomatic segmentation platform. Then, the model was trained under the supervision of the LDCT training set. Finally, the trained model was used to segment the LDCT in the test set. Dice coefficient, Jaccard coefficient, and Hausdorff distance were adopted as evaluation metrics to verify the performance of our segmentation model. Results In this study, the model achieved the accurate segmentation of each pulmonary lobe in seconds without the intervention of researchers. The testing set consisted 50 LDCT cases were used to evaluate the performance of the segmentation model. The all-lobes Dice coefficient of the test set was 0.944, the Jaccard coefficient was 0.896, and the Hausdorff distance was 92.908 mm. Conclusions The segmentation model based on LDCT can automatically and robustly and efficiently segment pulmonary lobes. It will provide effective location information and contour constraints for pulmonary nodule detection on LDCT images for lung cancer screening, which may have potential clinical application.

The monitoring of urban land surface subsidence is the main task of urban disaster prevention and mitigation. In this paper, the land surface subsidence process in Changchun metropolitan area is calculated based on PS-InSAR technology by using the SLC data of Sentinel-1B with 50 scenes within the metropolitan area of Changchun from 2016 to 2020. The results show that the metropolitan surface of Changchun is basically in a stable state, the main settlement is located in the southeast of the metropolitan around the Century Square, the maximum settlement rate is 20.45mm/a, the average settlement rate is 2.98mm/a, the correlation coefficient between the settlement results calculated by PS-InSAR and the second-class leveling verification results reaches 0.67, which indicates that the regional settlement results calculated by PS-InSAR have high reliability. The subsidence area is dominated by the geological structure of the Mesozoic Cretaceous Yaojia Formation, with many intercalations of fine silty sand rocks and locally containing medium-coarse gravel sandstone. The overall structural stability is poor, which may be the main reason for subsidence in this area.

Minor alloying with specific elements is an effective approach to tailor material's properties, but it has not been introduced to modify the radiation effects of high-entropy alloys (HEAs), which are a promising material for nuclear application. In the work, a 0.2 molar ratio of Al/Cu/Ti was respectively added into the quaternary FeCoNiCr HEA, they were then irradiated by 2 MeV He ions at four temperatures from 673 to 973 K. After irradiation, He bubble behavior in specimens were investigated by the transmission electron microscopy (TEM). The results showed that bubbles in the minor alloying HEAs usually had a larger size, lower number density, and broader distribution range, comparing to their parent alloy. Such effects were more significant at a higher irradiation temperature and most pronounced by the Ti-addition. Atomistic simulations revealed that such minor alloying addition could relatively reduce the energy barrier for vacancy migration and formation in FeCoNiCr system, which thereby promotes He diffusion through the replacement or vacancy mechanism. The theoretical models for He bubble formations verified our results that a higher He diffusivity in the minor alloying HEAs can enhance bubble growth and lower its nucleation numbers during irradiation. The phase stability of irradiated HEAs were also examined and its potential influences on bubble evolution were pointed out. This study provides insights on tailoring radiation defects via the conventional alloying strategy.