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Laboratory studies of the disposition and toxicity of hydroxylated polychlorinated biphenyl (OH-PCB) metabolites are challenging because authentic analytical standards for most unknown OH-PCBs are not available. To assist with the characterization of these OH-PCBs (as methylated derivatives), we developed machine learning-based models with multiple linear regression (MLR) or random forest regression (RFR) to predict the relative retention times (RRT) and MS/MS responses of methoxylated (MeO-)PCBs on a gas chromatograph-tandem mass spectrometry system. The final MLR model estimated the retention times of MeO-PCBs with a mean absolute error of 0.55 min (n = 121). The similarity coefficients cos θ between the predicted (by RFR model) and experimental MS/MS data of MeO-PCBs were >0.95 for 92% of observations (n = 96). The levels of MeO-PCBs quantified with the predicted MS/MS response factors approximated the experimental values within a 2-fold difference for 85% of observations and 3-fold differences for all observations (n = 89). Subsequently, these model predictions were used to assist with the identification of OH-PCB 95 or OH-PCB 28 metabolites in mouse feces or liver by suggesting candidate ranking information for identifying the metabolite isomers. Thus, predicted retention and MS/MS response data can assist in identifying unknown OH-PCBs.

Background To clarify the relationship between CD74 and atherosclerosis (AS) and the mechanisms in oxidized LDL (ox-LDL)-induced endothelial cell and macrophage injury. Methods Datasets obtained from the Gene Expression Omnibus database are integrated. Differentially expressed genes (DEGs) were obtained using R software. Weighted gene co-expression network analysis (WGCNA) was performed to screen the target genes. The endothelial cell injury model and macrophage foaming model were established using ox-LDL, and CD74 expression was detected by Quantitative reverse transcription PCR (RT-qPCR) and Western blot (WB). Then, after silencing CD74, cell viability and ROS production were measured, and WB detected the expression of p-p38 MAPK and NF-κB. Results 268 DEGs were associated with AS, of which CD74 was upregulated. The turquoise module containing CD74 in WGCNA was positively associated with AS. In the endothelial cell injury model and macrophage foaming model, cell viability was significantly decreased, and CD74, ROS production, NF-κB, and p-p38MAPK expression were increased (P

Engineering Janus structures that possess anisotropic features in functions have attracted growing attention for a wide range of applications in sensors, catalysis, and biomedicine, and are yet usually designed at the nanoscale with distinct physical or chemical functionalities in their opposite sides. Inspired by the seamless integration of soft and hard materials in biological structures, here a mechanical Janus structure composed of soft and hard materials with a dramatic difference in mechanical properties at an additively manufacturable macroscale is presented. In the combination of extensive experimental, theoretical, and computational studies, the design principle of soft-hard materials integrated mechanical Janus structures is established and their unique rotation mechanism is addressed. The systematic studies of assembling the Janus structure units into superstructures with well-ordered organizations by programming the local rotations are further shown, providing a direct route of designing superstructures by leveraging mechanical Janus structures with unique soft-hard material integration. Applications are conducted to demonstrate the features and functionalities of assembled superstructures with local ordered organizations in regulating and filtering acoustic wave propagations, thereby providing exemplification applications of mechanical Janus design in functional structures and devices.

Circulating microRNAs (miRNA) can serve as key biomarkers for early diagnose of cholangiocarcinoma. Herein, an assay that uses circulating miRNA to trigger strand displacement amplification (SDA) and a CRISPR-Cas14a system to report the SDA process has been developed. In the proposed method, SDA directly amplifies miRNAs without reverse transcription. The reporter, CRISPR-Cas14a, can reduce the risks of non-specific amplification and offers a sequential amplification that improves the sensitivity for miRNA detection. The assay, termed Cas14SDA, can discriminate miRNAs with similar sequences and can detect as low as 680 fM miR-21 (miRNAs overexpressed in cholangiocarcinoma) within 1 h. In particular, Cas14a was efficiently activated by a single-stranded SDA amplicon which improved the sensitivity by 2.86 times compared to that using Cas12a. This research has demonstrated that the Cas14SDA assay can discriminate cholangiocarcinoma patients from healthy donors by testing miR-21 in their blood samples. The Cas14SDA assay developed broadens the toolbox for miRNA biomarker analysis.

Purpose Insertion of radioactive strips through the biliary stent has been reported to offer longer survival and patency than an uncovered conventional self-expanding metal stent in patients with unresectable malignant biliary obstruction. The aim of this study was to investigate the safety and effectiveness of intraluminal brachytherapy combined with 125I seed implantation and transarterial infusion chemotherapy for the treatment of pancreatic head cancer with obstructive jaundice. Method From October 2012 to January 2018, 21 consecutive patients diagnosed with biliary obstruction caused by locally advanced, nonmetastatic pancreatic cancer with cytologically or histologically confirmed by biopsy were enrolled and receive treatment with intraluminal brachytherapy using 125I seed strand and CT-guided percutaneous radioactive seed implantation therapy. The procedure-related and radiation complications were assessed. The outcomes were measured in terms of stent patency, patient survival, complications related to the procedure. Result One of the 22 patients (4.5%, 1/22) with pancreatic head cancer failed to perform the above procedure because the guidewire was unable to pass through the obstruction segment. The remaining 21 patients (95.5%, 21/22) with pancreatic head cancer with obstructive jaundice were successfully placed with biliary stents and radioactive strips through drainage tubes. The median number of 125I seeds loaded was 15, ranging from 12 to 17. After the chemotherapy with gemcitabine and cisplatin, no adverse reaction of Grade Ⅲ ∼ Ⅳ occurred in all cases. Median stent patency was 12.50 months (95% CI: 10.26, 14.74). By May 2019, all 21 patients had died, with overall survival of 5.2–23.3 months, with a median survival of 13.20 months (95% CI: 10.96, 15.44). Conclusion Percutaneous 125I seed implantation combined with insertion of radioactive strips through the biliary stent has the characteristics of less trauma, fewer complications, simple operation, and so on. These procedures bring remission of obstructive jaundice combined with the increased survival for the treatment of obstructive jaundice caused by unresectable pancreatic head cancer if follow-up chemotherapy is carried out. The long-term efficacy of this treatment combination needs to be confirmed by further multicenter, large sample size prospective randomized controlled studies.

Purpose: To investigate the involvement of transthyretin (TTR) in promoting cholangiocarcinoma (CCA) cell invasion by macrophages and to elucidate the role of TTR in cholangiocarcinoma migration and invasion.Methods: Immunohistochemical detection of TTR, TNF-α and IL-6 expression in CCA tissues. CCA cells (HCCC9810) with high expression of TTR were co-cultured with macrophages (THP-1) in the presence of TNF- α (25 ng/L), which were divided into: blank control group (BC group), negative control group (NC group), HCCC9810 + si-RNA TTR, HCCC9810 + recombinant TTR, HCCC9810 + Akt inhibitor (mk-2206). BC group were without THP-1 and TNF- α and no THP-1 were in NC group. The quantitative real-time PCR was used to determine the TTR levels in cells. Cell proliferation was detected by CCK8 assay. The metastatic ability was detected by wound-healing migration assay, and Transwell assay was used to detect the invasive ability, TTR, NF-κB and p-Akt protein levels were detected by Western blot.Results: Expression of IL-6 and TTR was increased in CCA tissues. Both THP-1 and downregulation of TTR could inhibit the metastatic and invasive abilities of HCCC9810 cells (P < 0.05), and downregulated NF-κB and p-Akt expression (P < 0.05). Recombinant TTR recovered the metastatic and invasive abilities of HCCC9810 cells and upregulated NF-κB and p-Akt expression (P < 0.05). Mk-2206 downregulated the metastatic ability and the expression of TTR and NF-κB in HCCC9810 cells (P < 0.05).Conclusion: TTR promotes the invasion abilities of HCCC9810 cells by macrophages in the tumor microenvironment though Akt and NF-κB signaling pathways.

Stretchable metasurface comprised of an array of optical hard-material scatters on the surface of a soft substrate is emerging as an artificially designed structure to manipulate optical wave propagation through a mechanical means. Upon stretching the soft substrate, along with the increase of the spacing distance between hard scatters, the orientations of the hard scatters will vary due to their strong mechanical mismatch with the soft substrate, but the underlying mechanics mechanism is lacking. In the present study, we establish a theoretical mechanics framework to address the rotation of hard scatters bonded on the surface of a soft substrate subjected to a mechanical stretching load. In this model, we introduce a pseudo-interface between the hard scatters and the soft substrate and decouple the effect of in-plane stretching deformation and out-of-plane deformation in the thickness direction of the soft substrate on the basis of moment equilibrium. Besides, the shear stress field along the thickness direction of three-dimensional soft substrate is formulated from that of a two-dimensional plane model by introducing a thickness factor. The effect of spacing distance, geometric shape, and initial orientation of hard scatters and thickness of the soft substrate on the scatter rotation is elucidated. Extensive finite element analyses (FEA) are performed and the results show good agreement with the theoretical predictions in both scatter rotation and stress distribution. We further construct a stretchable metasurface and demonstrate that the refraction of incident lights can be tuned by controlling the rotation of scatters. The mechanics theory established here provides a foundation to design mechanically controllable metasurfaces by leveraging the rotation of hard-material scatters.

Introduction: Lenvatinib is the first-line treatment for advanced hepatocellular carcinoma (HCC). We aimed to compare the clinical outcomes of lenvatinib plus drug-eluting beads transarterial chemoembolization (DEB-TACE) versus lenvatinib alone in real-world practice. Methods: This retrospective analysis included 142 consecutive patients who received lenvatinib plus DEB-TACE and 69 patients who received lenvatinib alone as first-line treatment from 15 Chinese academic centers from November 2018 to November 2019. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR) were evaluated by modified Response Evaluation Criteria in Solid Tumors criteria, and safety profiles were compared between the two groups. Results: The median OS and PFS were significantly longer in the combined therapy group than in the monotherapy group in whole cohort (median OS, 15.9 vs. 8.6 months, p = 0.0022; median PFS, 8.6 vs. 4.4 months, p < 0.001) and after propensity score matching analysis (median OS, 13.8 vs. 7.8 months, p = 0.03; median PFS, 7.8 vs. 4.5 months, p = 0.009). Moreover, the treatment option was an independent prognostic factor for OS and PFS with adjustment based upon baseline characteristics (adjusted hazard ratio [HR]: 0.53, 95% confidence interval [CI]: 0.36–0.78, p = 0.001, and adjusted HR: 0.42, 95% CI: 0.30–0.60, p < 0.001, respectively) and propensity score (adjusted HR: 0.52, 95% CI: 0.36–0.76, p = 0.001, and adjusted HR: 0.46, 95% CI: 0.33–0.64, p < 0.001, respectively). Moreover, a greater ORR was observed in the combined group (ORR: 46.48% vs. 13.05%, p < 0.001). Furthermore, the most common adverse events (AEs) were elevated aspartate aminotransferase (54.9%) and fatigue (46.4%) in the lenvatinib plus DEB-TACE group and lenvatinib group, respectively. Most AEs were mild-to-moderate and manageable. Conclusions: With well-tolerated safety, lenvatinib plus DEB-TACE was more effective than lenvatinib monotherapy in improving OS, PFS, and ORR. Thus, it may be a promising treatment for advanced HCC. Future prospective studies confirming these findings are warranted.

The majority of patients with hepatocellular carcinoma (HCC) are diagnosed in an advanced stage. Although sorafenib is recommended as the standard treatment for advanced HCC, its efficacy is limited. In some studies, hepatic arterial infusion chemotherapy has demonstrated a significant therapeutic benefit for advanced HCC compared with sorafenib. We systematically evaluated and compared the efficacy and safety of hepatic arterial infusion chemotherapy and sorafenib for advanced HCC.A systematic search of PubMed, Embase, Web of Science and the Cochrane Library up to December 31, 2020 was conducted. Study outcomes included overall survival (OS), progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and adverse effects. The hazard ratio and odds ratio with 95% confidence intervals (CI) were used to measure the pooled effect.Eighteen retrospective or prospective cohort studies and one prospective controlled study were included, with 1,339 patients treated with hepatic arterial infusion chemotherapy (HAIC) and 1,060 patients treated with sorafenib. We found that hepatic arterial infusion chemotherapy was superior to sorafenib in terms of OS [hazard ratio (HR): 0.66, 95% CI: 0.46-0.95, P=0.027], PFS (HR: 0.55, 95% CI: 0.44-0.69, P0.001), ORR [assessed using Response Evaluation Criteria in Solid Tumors (RECIST): OR: 9.02, 95% CI: 6.01-13.53, P0.001; assessed using modified RECIST: odds ratio (OR): 3.71, 95% CI: 1.92-7.16, P0.001], and DCR (assessed using RECIST: OR: 2.31, 95% CI: 1.40-3.83, P=0.001; assessed by modified RECIST: OR: 2.28, 95% CI: 1.22-4.28, P=0.01). Dermatological adverse effects and hypertension were significantly higher in the sorafenib group for all grades of adverse effects. However, regarding severe adverse effects, hepatic arterial infusion chemotherapy was associated with more frequent leukocytopenia and thrombocytopenia.Hepatic arterial infusion chemotherapy demonstrated favorable efficacy and safety for advanced HCC compared with sorafenib and should be recommended for suitable patients with advanced HCC.

Background: Residual viable tumor cells after ablation at the tumor periphery serve as the source for tumor recurrence, leading to treatment failure. Purpose: To develop a novel three-dimensional (3D) multi-modal perfusion-thermal electrode system completely eradicating medium-to-large malignancies. Materials and Methods: This study included five steps: (i) design of the new system; (ii) production of the new system; (iii) ex vivo evaluation of its perfusion-thermal functions; (iv) mathematic modeling and computer simulation to confirm the optimal temperature profiles during the thermal ablation process, and; (v) in vivo technical validation using five living rabbits with orthotopic liver tumors. Results: In ex vivo experiments, gross pathology and optical imaging demonstrated the successful spherical distribution/deposition of motexafin gadolinium administered through the new electrode, with a temperature gradient from the electrode core at 80 °C to its periphery at 42 °C. An excellent repeatable correlation of temperature profiles at varying spots, from the center to periphery of the liver tumor, was found between the mathematic simulation and actual animal tumor models (Pearson coefficient ≥0.977). For in vivo validation, indocyanine green (ICG) was directly delivered into the peritumoral zones during simultaneous generation of central tumoral lethal radiofrequency (RF) heat (>60 °C) and peritumoral sublethal RF hyperthermia (

Fretting fatigue damage can significantly reduce the service life of Ni-based single crystal (NBSX) superalloys turbine blades. In this work, we proposed a fretting fatigue life prediction method by considering cracking, wear and their mutual interaction. Specifically, a parameter, denoted as RA, is developed with combination of Resolved shear stress based damage factor and Accumulated dissipated energy based damage factor, by which the contribution from cracking and wear are described respectively. The proposed method is validated with experimental data in the literature. Finite element analyses are performed to study the distribution of stresses and strains. Results show that the predicted crack initiation site, failure plane and life cycles are consistent with the experimental results.

In a traditional multidisciplinary design optimization loop for complex-shaped structures, the regeneration of structure geometry and its associated analysis grids may be unsuccessful or of poor qu...

In this work, the anisotropic tensile properties of laser additive manufactured (LAMed) GH4169 in as deposited and different heat-treated conditions are presented and the underlying mechanisms are analyzed in detail. Vertical and horizontal specimens for tensile tests were taken from as deposited (AD) and heat-treated blocks. Two heat treatment conditions with solution temperature of 980 °C and 1050 °C were considered. The tensile test results indicate different tensile properties of the vertical and horizontal samples, and such anisotropy is related to heat treatment conditions. The vertical AD sample has higher tensile strength than its horizontal counterpart, while after heat treatment, the horizontal direction shows higher tensile strength. Microstructure characterization, texture and grain morphology analyses were conducted through SEM with EBSD, XRD and TEM observations in order to figure out the main influential factors of the anisotropic tensile properties. Besides, fracture surfaces of the tensile specimens were observed to study the role of precipitates. In addition, the residual stresses in the LAMed samples in AD and heat-treated conditions were measured, and their effects on the anisotropic tensile strength were clarified by correlating the residual stress levels with the recrystallization fractions extracted from EBSD data. The obtained results show that a large number of brittle Laves phases growing along the vertical direction are distributed in the AD samples, which leads to different separation manners of Laves phase/γ matrix interfaces under different loading directions. Besides, the residuals stress level is high direction dependent in the AD samples. After heat treatment, most of the Laves phases are dissolved, and the residual stress experiences a significant variation. On the whole, the anisotropic tensile strength is mainly influenced by the residual stress level before and after heat treatment, and slightly influenced by the dissolution of the Laves phase. The present study provides a deeper understanding of the anisotropic tensile properties of LAMed GH4169, which may contribute to future engineering applications of Ni-based superalloys.

Amorphous carbon probably is the most-known and widely used carbon allotrope. However, unlike crystalline carbon such as graphene or carbon nanotubes, amorphous carbon generally is brittle and unable to sustain large mechanical deformation due to the inherent lack of long-rang order. In this work, we demonstrate a significant delay of failure on an amorphous carbon hollow nanosphere due to the buckling and post-buckling deformation of the spherical shell. Both in situ experiments and finite element analyses are conducted to probe deformation mechanism of buckling and post-buckling, suggesting a strong dependence of the shell thickness on the buckling process. A unified deformation energy-based mechanics model is developed to extract the critical buckling and post-buckling force, and shows good agreement with in situ experiments and finite element analyses. Extension of the model to inhomogeneous hollow nanospheres is also discussed and confirmed with finite element analyses.

During billions of years of evolution, creatures in nature have possessed nearly perfect structures and functions for survival. Multiscale structures in biological materials over several length scales play a pivotal role in achieving structural and functional integrity. Fiber, as a common principal structural element in nature, can be easily constructed in different ways, thus resulting in various natural structures. In this review, we summarized the decades of investigations on a typical biological structure constructed by fiber aragonites in mollusk shells. Crossed-lamellar structure, as one of the most widespread structures in mollusk shells, reconciles the strength-toughness trade-off dilemma successfully due to the presence of highly-hierarchical architectures. This distinctive structure includes several orders of sub-lamellae, and the different order lamellae present a cross-ply feature in one macro crossed-lamellar layer. When a mollusk shell has more than one macro-layer, the crossed-lamellar structure exhibits various forms of architectures including 0°/90°, 0°/90°/0° typical-sandwich, 15°/75°/0° quasi-sandwich, and 0°/90°/0°/90° arranged modes. The fracture resistance and the relevant toughening mechanisms are directly related to the highly-hierarchical crossed-lamellar structures on different length scales. This article is aimed to review the different arranged modes of crossed-lamellar structures existing in nature, with special attention to their impact on the mechanical behavior and salient toughening mechanisms over several length scales, for seeking the design guidelines for the fabrication of bio-inspired advanced engineering materials that are adaptive to different loading conditions.

Spontaneous iliac vein rupture is a relatively rare but fatal disease. Herein, 2 cases are reported. The two middle-aged and elderly females complaining of abdominal pain were admitted without any history of trauma. The computed tomography image both showed one huge hematoma in the lower abdominal cavity and the left external iliac venous thrombus. Venogram showed ruptures of the left external iliac vein and stenosis of the left common iliac vein after percutaneous mechanical thrombectomy. Stent grafts were implanted by endovascular technique. Favorable outcomes were achieved in both cases.

Soft–hard materials integration is ubiquitous in biological materials and structures in nature and has also attracted growing attention in the bio-inspired design of advanced functional materials, structures and devices. Due to the distinct difference in their mechanical properties, the rotation of hard phases in soft matrixes upon deformation has been acknowledged, yet is lack of theory in mechanics. In this work, we propose a theoretical mechanics framework that can describe the rotation of hard particles in a soft matrix. The rotation of multiple arbitrarily shaped, located and oriented particles with perfectly bonded interfaces in an elastic soft matrix subjected to a far-field tensile loading is established and analytical solutions are derived by using complex potentials and conformal mapping methods. Strong couplings and competitions of the rotation of hard particles among each other are discussed by investigating numbers, relative locations and orientations of particles in the matrix at different loading directions. Extensive finite element analyses are performed to validate theoretical solutions and good agreement of both rotation and stress field between them are achieved. Possible extensions of the present theory to non-rigid particles, viscoelastic matrix and imperfect bonding are also discussed. Finally, by taking advantage of the rotation of hard particles, we exemplify an application in a conceptual design of soft-hard material integrated phononic crystal and demonstrate that phononic band gaps can be successfully tuned with a high accuracy through the mechanical tension-induced rotation of hard particles. The present theory established herein is expected to be of immediate interests to the design of soft–hard materials integration based functional materials, structures and devices with tunable performance via mechanical rotation of hard phases.

Aerodynamic design is of great importance in the overall design of flight vehicles. In this study, an approach to aerodynamic design optimization is proposed by integrating Bezier curve parameterization and radial basis interpolation to enable large variation of aerodynamic profile during optimization. The Bezier curve uses the shape of a given airfoil and the radial basis function interpolation is applied to smoothly transfer the perturbation to the mesh in the whole flow field. Using design of experiments technique, the prominent design parameters that significantly affect the aerodynamic performance are determined. Aerodynamic optimizations are conducted for a wing airfoil and a blade airfoil to verify the efficiency of the proposed method. Genetic algorithm is employed in both single-objective and multiobjective design cases. Design results show that the present method can significantly improve the aerodynamic performance due to its capability to handle large shape changes of the airfoil. This work provides a useful and powerful tool to aerodynamic design with applications to various flight vehicles.

An auxetic design is proposed by soft–hard material integration and demonstrate negative Poisson's ratio (NPR) can be achieved by leveraging unique rotation features of non-connected hard particles in a soft matrix. A theoretical mechanics framework that describes rotation of hard particles in a soft matrix under a mechanical loading is incorporated with overall Poisson's ratio of the soft–hard integrated metamaterials. The theoretical analysis shows that the auxetic behaviour of the soft–hard integrated structures not only relies critically on geometry of particles, but also depends on their periodic arrangements in the soft matrix. Extensive finite-element analyses (FEA) are performed and validate the theoretical predictions of hard-particle rotation and overall Poisson's ratio of soft–hard integrated structures. Furthermore, uniaxial tensile tests are carried out on three-dimensional printed soft–hard integrated structures and confirm auxetic behaviour of soft–hard integrated structures enabled by the rotation of hard particles. Besides, Poisson's ratio varies nonlinearly with the thickness of specimens and reaches a maximum NPR far out of the bounds of plane stress and plane strain situations, which agrees well with FEA. This work provides a theoretical foundation for the design of mechanical metamaterials enabled by soft–hard material integration with auxetic deformation behaviour.

The hippocampus is a crucial pathological node for minimal hepatic encephalopathy (MHE) and it is associated with various cognitive impairments. Investigations on alterations involving hippocampal morphology and functional connectivity (FC) in MHE are limited. This study aimed to simultaneously evaluate hippocampal volume and FC alterations and their association with cognitive decline in MHE. Twenty-two cirrhotic patients with MHE, 31 cirrhotic patients without MHE (NHE), and 43 healthy controls underwent high-resolution T1-weighted imaging, resting-state functional magnetic resonance imaging, and cognition assessment based on Psychometric Hepatic Encephalopathy Score (PHES). The structural images were preprocessed using a voxel-based morphometry method, during which hippocampal volume was measured. The hippocampal connectivity network was identified using seed-based correlation analysis. Hippocampal volume and FC strength were compared across the three groups and correlated against the PHES results of the cirrhotic patients. Compared to the controls, MHE patients exhibited a significantly lower bilateral hippocampal volume. A slight decrease in hippocampal volume was obtained from NHE to MHE, but it did not reach statistically significance. In addition, the average FC strength of the bilateral hippocampal connectivity network was significantly lower in the MHE patients. In particular, the MHE patients showed a decrease in FC involving the left hippocampus to bilateral posterior cingulate gyrus and left angular gyrus. The MHE patients also showed FC reduction between the right hippocampus and bilateral medial frontal cortex. A progressive reduction in hippocampal FC from NHE to MHE was also observed. The bilateral hippocampal FC strength (but not hippocampal volume) was positively correlated with the PHES results of the cirrhotic patients. Our assessment of MHE patients revealed decreased hippocampal volume, which suggests regional atrophy, and reduced hippocampal connectivity with regions that are primarily involved in the default-mode network, thereby suggesting a functional disconnection syndrome. These alterations reveal the mechanisms underlying cognitive deterioration with disease progression.

The fretting fatigue behaviors of a nickel-based single crystal superalloy in contact with a powder metallurgy alloy at 600 °C are investigated. Fretting fatigue tests are conducted by using a novel high temperature fretting fatigue test apparatus that is developed, and the crystal plasticity finite element method is used to analyze the contact stress and activations of slip systems. The results show that the fretting conditions are partial slip regime for all loading conditions, and severe wear damage occurs across the slip region, which is accompanied by surface delamination and micro crack. Fretting fatigue cracks mainly initiate at the contact leading edge area, i.e., the stress concentration zone. The cracks grow along the (100) plane when multiple octahedral slip systems are activated simultaneously, or could be eliminated by wear. Considering the effects of both crystallographic slip and wear on the fretting fatigue damage, an improved fretting fatigue damage parameter, RA, is proposed to predict the fretting fatigue life. The predicted results agree well with the test results.

Energy absorption structures have been pursued to protect personnel and infrastructures over the last few decades. In this study, a novel hybrid foam-core/solid-shell spherical (FSS) structure is presented and investigated. The internal foam core inherits merits of large deformation from conventional foam structures and the introduction of the external thin solid shell is to reach high strength and delay deformation further, thereby achieving high energy absorption efficiency in FSS structures. Theoretical models are developed to characterize elastic modulus and buckling behavior of FSS structures under a compressive loading, and are verified through extensive finite element analysis (FEA). Typical deformation mechanisms are revealed by addressing competition of buckling deformation of the foam core and solid shell, and are identified through the proposed theoretical models. Further, the energy absorption efficiency is proposed to optimize the specific energy absorption density and critical triggering force of activating energy absorption, and is correlated with deformation mechanism and geometric parameters of FSS structures. Both numerical and theoretical analyses show that the employment of a thin solid shell surrounding the foam structures will enhance the energy absorption efficiency with high capability and safe comfort. The present study is expected to provide a useful guideline for a hybrid design of future energy absorption structures with unprecedented performance.

Curvilinear stiffener concept has been introduced to aircraft panel structures most recently for possible further weight reduction during optimization design. However, due to enlarged design space and high design complexity, more computational time is needed to optimize curvilinearly stiffened panels. Considering the requirement for both lighter structure and less design time, optimization designs of a unitized panel with stiffeners in three different formats, i.e. curvilinear, oblique, and evenly distributed straight, are conducted under various loading conditions to figure out which stiffener format should be selected in a real design environment. Four single loading cases with different compression-shear ratios and a set of multiple load cases are considered. Evolution strategy with covariance matrix adaption is combined with sequential quadratic programming to seek out the optimum structure with minimum mass taking into account buckling and strength constraints. Comparative analysis of the optimization results indicates that evenly distributed straight format is suitable for compression-dominant loading conditions whereas curvilinear format become superior in case that shear loading is considerable or multiple biaxial compression and shear loads are applied. Besides, curvilinear format adds more design flexibilities to the stiffeners, which enables them to play a more important role in the optimized structures. Furthermore, evolution strategy with covariance matrix adaption is found to be more efficient than particle swarm optimization for this optimization problem. This study can provide a useful guidance for future optimization design of aircraft structures.

Thermal conductivity of graphene nanoribbons usually decreases quickly with the increase of tensile strain due to the softened phonon modes and increased lattice anharmonicities. In this work, we present a new design of graphene nanoribbon structures—serpentine graphene nanoribbons (SGNRs) and demonstrate that thermal conductivity of SGNRs increases with the increase of tensile strain through nonequilibrium molecular dynamics (NEMD) simulations. This increase can be held till to as large as 54.7% stretchability of SGNRs. The unusual response of thermal conductivity results from the competition between the elongation of heat transfer path and stress distribution in nanoribbon structures under tension and is closely related with the maximum stretchability of serpentine structures. Both mechanical stress distribution and phonon spectrum of SGNRs are examined to understand the underlying thermal transport mechanism, and show good agreement with simulation findings.

Fretting fatigue failure behavior of DD6 Nickel-based single crystal superalloy dovetail attachment at 600 °C has been investigated. The contact surface material is oxidized at high temperature and the oxides are compacted on the contact surface. The contact surface is delaminated and many pits are formed, which result in stress concentration near the wear pits and promote crack initiation. All the dovetail specimens fail at the contact leading edge area and along (111) [ 1 1 ‾ 0 ] and ( 1 ‾ 1 1 ‾ ) [110] slip systems, which are resulted from the large resolved shear stress at the contact edge. Crystallographic plasticity finite element method is used to obtain the contact stress and strain, and the calculated maximum damage area agrees well with the experimental results.

Purpose The aims of this study were to evaluate treatment responses and predictive factors for overall survival (OS) in hepatocellular carcinoma (HCC) patients with portal vein tumor thrombosis (PVTT) treated with iodine-125 (125I) brachytherapy. Methods and Materials Seventy-seven HCC patients with PVTT underwent 125I brachytherapy after transcatheter arterial chemoembolization. Clinical, laboratory, and radiological evaluation were performed before and after treatment, as well as at 4–6 weeks intervals for 7 years to assess the efficacy and toxicity of therapy. Treatment response was assessed using modified response evaluation criteria in solid tumors. OS and predictive factors for each subgroup were evaluated after treatment. Results In total, 11 patients (14.29%) achieved complete response, and 41 patients (53.25%) achieved partial response. The response rate (complete response + partial response) was 67.53% (52/77). The median OS was 9 months. The multivariable Cox regression model indicated that post-treatment tumor size with PVTT (p = 0.016, hazard ratio [HR] = 1.889, 95% confidence interval [CI]: 1.127 to 3.166) and baseline hemoglobin (p = 0.013, HR=0.518, 95% CI: 0.308 to 0.872) and alkaline phosphatase (p = 0.002, HR=2.275, 95% CI: 1.338 to 3.868) levels were significant independent predictors of OS. Conclusions 125I brachytherapy results in favorable treatment responses in HCC patients with PVTT. Notably, post-treatment tumor size and baseline hemoglobin and alkaline phosphatase levels are significant independent predictive factors for OS and provide the most predictive information regarding OS.

An optimization procedure combining an automated finite element modelling (AFEM) technique with a ground structure approach (GSA) is proposed for structural layout and sizing design of aircraft wings. The AFEM technique, based on CATIA VBA scripting and PCL programming, is used to generate models automatically considering the arrangement of inner systems. GSA is used for local structural topology optimization. The design procedure is applied to a high-aspect-ratio wing. The arrangement of the integral fuel tank, landing gear and control surfaces is considered. For the landing gear region, a non-conventional initial structural layout is adopted. The positions of components, the number of ribs and local topology in the wing box and landing gear region are optimized to obtain a minimum structural weight. Constraints include tank volume, strength, buckling and aeroelastic parameters. The results show that the combined approach leads to a greater weight saving, i.e. 26.5%, compared with three additional optimi...