The Effect of Moisture on the Adhesion Energy and Nanostructure of Asphalt-Aggregate Interface System Using Molecular Dynamics Simulation.

In this work, the influences of moisture intruded into the asphalt-aggregate interface have been investigated at the atomistic scale. The molecular interactions of asphalt with limestone and granite were studied using molecular dynamics (MD) simulations and the mineral surface components of limestone and granite were detected using the hyperspectral image technique. Relative concentration and radial distribution function (RDF) were employed for the characterization of asphalt component aggregations on aggregates surface. Adhesion work and debonding energy were also evaluated to investigate interface energy variations in asphalt-aggregate systems. MD results showed that the presence of interfacial moisture modified asphalt nanostructure and affected the aggregation state and distribution characteristics of asphalt components near aggregate surface. The study also demonstrated that the external moisture that intruded into the interface of the asphalt-aggregate system can decrease the concentration distribution of the asphalt components with powerful polarity on aggregate surface, reduce the adhesion works of the asphalt-aggregate interface, and decline the water damage resistance of asphalt mixture.

Label-Aware Calibration and Relation-Preserving in Visual Intention Understanding.

Visual intention understanding is a challenging task that explores the hidden intention behind the images of publishers in social media. Visual intention represents implicit semantics, whose ambiguous definition inevitably leads to label shifting and label blemish. The former indicates that the same image delivers intention discrepancies under different data augmentations, while the latter represents that the label of intention data is susceptible to errors or omissions during the annotation process. This paper proposes a novel method, called Label-aware Calibration and Relation-preserving (LabCR) to alleviate the above two problems from both intra-sample and inter-sample views. First, we disentangle the multiple intentions into a single intention for explicit distribution calibration in terms of the overall and the individual. Calibrating the class probability distributions in augmented instance pairs provides consistent inferred intention to address label shifting. Second, we utilize the intention similarity to establish correlations among samples, which offers additional supervision signals to form correlation alignments in instance pairs. This strategy alleviates the effect of label blemish. Extensive experiments have validated the superiority of the proposed method LabCR in visual intention understanding and pedestrian attribute recognition. Code is available at https://github.com/ShiQingHongYa/LabCR.

Federated Learning for Generalization, Robustness, Fairness: A Survey and Benchmark.

Federated learning has emerged as a promising paradigm for privacy-preserving collaboration among different parties. Recently, with the popularity of federated learning, an influx of approaches have delivered towards different realistic challenges. In this survey, we provide a systematic overview of the important and recent developments of research on federated learning. Firstly, we introduce the study history and terminology definition of this area. Then, we comprehensively review three basic lines of research: generalization, robustness, and fairness, by introducing their respective background concepts, task settings, and main challenges. We also offer a detailed overview of representative literature on both methods and datasets. We further benchmark the reviewed methods on several well-known datasets. Finally, we point out several open issues in this field and suggest opportunities for further research. We also provide a public website to continuously track developments in this fast advancing field: https://github.com/WenkeHuang/MarsFL.

Generalizable Heterogeneous Federated Cross-Correlation and Instance Similarity Learning.

Federated learning is an important privacy-preserving multi-party learning paradigm, involving collaborative learning with others and local updating on private data. Model heterogeneity and catastrophic forgetting are two crucial challenges, which greatly limit the applicability and generalizability. This paper presents a novel FCCL+, federated correlation and similarity learning with non-target distillation, facilitating the both intra-domain discriminability and inter-domain generalization. For heterogeneity issue, we leverage irrelevant unlabeled public data for communication between the heterogeneous participants. We construct cross-correlation matrix and align instance similarity distribution on both logits and feature levels, which effectively overcomes the communication barrier and improves the generalizable ability. For catastrophic forgetting in local updating stage, FCCL+ introduces Federated Non Target Distillation, which retains inter-domain knowledge while avoiding the optimization conflict issue, fulling distilling privileged inter-domain information through depicting posterior classes relation. Considering that there is no standard benchmark for evaluating existing heterogeneous federated learning under the same setting, we present a comprehensive benchmark with extensive representative methods under four domain shift scenarios, supporting both heterogeneous and homogeneous federated settings. Empirical results demonstrate the superiority of our method and the efficiency of modules on various scenarios. The benchmark code for reproducing our results is available at https://github.com/WenkeHuang/FCCL.

Study on the Adhesion Performance of Asphalt-Calcium Silicate Hydrate Gel Interface in Semi-Flexible Pavement Materials Based on Molecular Dynamics.

The interface between an asphalt binder and a calcium silicate hydrate (C-S-H) gel is a weak point of semi-flexible pavement material. In this study, the adhesion performance of asphalt-C-S-H gel interface in semi-flexible pavements at a molecular scale has been investigated. Molecular dynamics (MD) simulations were applied to establish three asphalt binders: 70# asphalt binder (the penetration is 70 mm), PG76-22 modified asphalt binder (a kind of asphalt binder that can adapt to the highest temperature of 76 °C and the lowest temperature of -22 °C), and S-HV asphalt binder (super high viscosity). The effects of different temperatures and SBS modifier contents on interfacial adhesion were explored. The obtained results showed that temperature variations had little effect on the adhesion work of the asphalt-C-S-H gel interface. It was also found that by increasing the content of SBS modifier, the adhesion work of the asphalt-C-S-H gel interface was increased. The molecular weight of each component was found to be an important factor affecting its molecular diffusion rate. The addition of SBS modifier could regulate the adsorption of aromatics by C-S-H gel in the four components of asphalt binder and improve the adsorption of resins by C-S-H gel.

An Experimental Study on Properties of Pre-Coated Aggregates Grouting Asphalt Concrete for Bridge Deck Pavement.

Epoxy asphalt concrete, mortar asphalt concrete and Gussasphalt concrete are commonly used types of deck pavement materials in bridge deck pavement engineering. However, achieving the high-temperature stability and anti-fatigue performance of the deck pavement materials is still challenging. In order to reduce the rutting and cracking risks of the asphalt mixture, this paper proposed pre-coated aggregates grouting asphalt concrete (PGAC) for bridge deck pavement. Laboratory tests were conducted to determine the optimum grouting materials and to evaluate the mechanical performances of the PGAC material. Test results showed that the mechanical properties for PGAC with grouting material of high-viscosity-modified asphalt binder blending with mineral filler were superior to that of GMA-10 used for the Hong Kong-Zhuhai-Macau Bridge deck pavement. Microstructural analysis showed that the PGAC had a more stable skeleton structure compared to other typical aggregate mixtures. This study highlights the performances of the proposed PGAC and sheds light on the deck pavement material improvement of both high-temperature stability and anti-fatigue performance that could be achieved.

Study on the Road Performance of Foamed Warm-Mixed Reclaimed Semi-Flexible Asphalt Pavement Material.

Warm-mixed reclaimed asphalt pavement (RAP) technology has been widely studied worldwide as a recycled environmental method to reuse waste materials. However, the aggregate skeleton structure of the warm-mixed reclaimed asphalt mixture is not stable because of the existence of the recycled materials. Warm-mixed recycled semi-flexible pavement material can solve the defects of the above materials. In this study, five different types of open-graded asphalt mixtures containing different contents of RAP were designed, and relevant laboratory tests were conducted to assess the road performance of the warm-mixed recycled semi-flexible pavement material. The test results indicated that the road performance of warm-mixed reclaimed semi-flexible pavement materials has good resistance to rut deformation ability. Furthermore, the materials also had good water stability and fatigue performance. The grey correlation analysis shows that the asphalt binder content has the most significant correlation with the high-temperature stability, and the correlation between RAP content and the fatigue performance was the greatest. Furthermore, the curing age has the most remarkable with the low-temperature crack resistance of the warm-mixed reclaimed semi-flexible material.

Ultrasonography predicts the results of labial salivary gland biopsy in patients with suspected Sjögren's syndrome: a matrix risk model.

OBJECTIVE: Although a positive result of labial salivary gland biopsy (LSGB) is critical for the diagnosis of Sjögren's syndrome, rheumatologists prefer assessing the non-invasive objective items and hope to learn the predicted probability of positive LSGB before referring patients with suspected Sjögren's syndrome to receive biopsy. This study aimed to explore the predictive value of combined B-mode ultrasonography (US) and shear-wave elastography (SWE) examination on LSGB results. METHODS: A derivation cohort and later a validation cohort of patients with suspected Sjögren's syndrome were recruited. All participants received clinical assessments, B-mode US and SWE examination on bilateral parotid and submandibular glands before LSGB. Positive LSGB was defined by a focus score ⩾1 per 4 mm2 of glandular tissue. RESULTS: In the derivation cohort of 91 participants, either the total US scores or the total SWE values of four glands significantly distinguished patients with positive LSGB from those with negative results (area under the curve (AUC) = 0.956, 0.825, both p < 0.001). The positive predictive value (PPV) was 100% in patients with total US scores ⩾9 or with total SWE values ⩾33 kPa. The negative predictive value (NPV) was 100% in patients with total US scores <5, but 68% in patients with total SWE values <27 kPa. A matrix risk model was derived based on the combination of total US scores and total SWE values. Patients can be stratified into high, moderate, and low risk of positive LSGB. In the validation cohort of 52 participants, the PPV was 94% in the high-risk subpopulation and the NPV was 93% in the low-risk subpopulation. CONCLUSION: A novel matrix risk model based on the combined B-mode US and SWE examination can help rheumatologists to make a shared decision with suspected Sjögren's syndrome patients on whether the invasive procedure of LSGB should be performed.

Traffic Safety Perception, Attitude, and Feeder Mode Choice of Metro Commute: Evidence from Shenzhen.

Like many other transit modes, the metro provides stop-to-stop services rather than door-to-door services, so its use undeniably involves first- and last-mile issues. Understanding the determinants of the first- and last-mile mode choice is essential. Existing literature, however, mostly overlooks the mode choice effects of traffic safety perception and attitudes toward the mode. To this end, based on a face-to-face questionnaire survey in Shenzhen, China, this study uses the two-sample t-test to confirm the systematic differences in traffic safety perception and attitudes between different subgroups and develops a series of multinomial logistic (MNL) models to identify the determinants of first- and last-mile mode choice for metro commuters. The results of this study show that: (1) Walking is the most frequently used travel mode, followed by dockless bike-sharing (DBS) and buses; (2) Variances in traffic safety perception and attitude exist across gender and location; (3) Vehicle-related crash risks discourage metro commuters from walking to/from the metro station but encourage them to use DBS and buses as feeder modes; (4) DBS-metro integration is encouraged by the attitude that DBS is quicker than buses and walking, and positive attitudes toward the bus and DBS availability are decisive for the bus-metro and DBS-metro integration, respectively; and (5) Substantial differences exist in the mode choice effects of traffic safety perception and attitudes for access and egress trips. This study provides a valuable reference for metro commuters' first- and last-mile travel mode choice, contributing to developing a sustainable urban transport system.

Optimizing Gradation Design for Ultra-Thin Wearing Course Asphalt.

In recent years, ultra-thin wearing course asphalt mixture has been widely used in the reconstruction of old road surfaces and the functional layer of new road surfaces due to its good road performance. To improve the rutting resistance of ultra-thin wearing course asphalt mixture, this research presents an Ultra-thin Wearing Course-10 (UTWC-10) asphalt mixture with good high-temperature stability and skid resistance based on the Taylor system standard mesh specifications. The Course Aggregate Void Filling (CAVF) method is used to design the UTWC-10 asphalt mixture, which is compared with two other traditional ultra-thin wearing course asphalt mixtures on the basis of different laboratory performance tests. The high-temperature rutting test data shows that the rutting dynamic stability (DS) index of the UTWC-10 asphalt mixture is much higher than that of traditional wearing course asphalt mixtures, as it has better high-temperature stability. Moreover, anti-sliding performance attenuation tests are conducted by a coarse aggregate polishing machine. The wear test results show that the skid resistance of the UTWC-10 asphalt mixture is promising. The anti-sliding performance attenuation test can effectively reflect the skid resistance attenuation trend of asphalt pavement at the long-term vehicle load. It is verified that the designed UTWC-10 asphalt mixture shows excellent high-temperature rutting resistance and skid resistance, as well as better low temperature crack resistance and water stability than the traditional wearing course asphalt mixtures.

Influence of Nominal Maximum Aggregate Size and Aggregate Gradation on Pore Characteristics of Porous Asphalt Concrete.

Porous asphalt concrete (PAC) has been used to improve the traffic conditions in rainy weather due to its high porosity. Aggregate size and gradation have great impact on the connected pore structure, which ultimately affects the permeability of porous asphalt concrete. In this paper, the topological properties of connective pores including pore area, pore circularity, equivalent pore diameter, and void network of porous asphalt concrete with different nominal maximum aggregate sizes and gradations were analyzed using x-ray computer tomography scans and the image processing technique. It was observed that the maximum aggregate sizes will not have significant effect on the percentage of connected pores to total pores for porous asphalt concrete. Furthermore, the percentage of connected pores to total pores is related to the air void content, but for PAC-13 with 20% target air void content or above, the connectivity does not seem to have a sharp increase. Additionally, porous asphalt concrete with a smaller nominal particle size or lower target air void content seems to generate a more concentrated distribution of Eqdiameter. Moreover, pore circularities for porous asphalt concrete with a maximum aggregate size of 10 mm or above are independent of maximum aggregate sizes. Air void contents ranging from 16% to 21% do not have a significant effect on the voids' circularity. Furthermore, the branching nodes in porous asphalt concrete with a smaller nominal maximum aggregate size or lower target air void content have a more uniform spatial distribution. However, the percentage of cross-linked number to total node raises as the nominal maximum aggregate size or target air void content increases.

Investigation of the Effects of Adsorbed Water on Adhesion Energy and Nanostructure of Asphalt and Aggregate Surfaces Based on Molecular Dynamics Simulation.

The purpose of this study was to investigate the effect of aggregate surface adsorbed water on the adhesive capacity and nanostructure of asphalt-aggregate interfaces at the atomic scale. Molecular dynamics (MD) simulation was performed to measure and analyze the molecular interactions of asphalt binder with calcite and silica. Radial distribution function (RDF) and relative concentration (RC) were applied to characterizing the concentrations and distributions of asphalt components on aggregate surfaces. In addition, debonding energy and adhesion energy were employed to calculate the variations of interface adhesion energy of the asphalt-aggregate system under different conditions. The obtained results illustrated that the water molecules adsorbed onto the surface of weakly alkaline aggregates inhibited the concentration and distribution of asphalt components near the aggregate surface, decreased adhesion energy between asphalt and aggregates, and changed asphalt nanostructure. Especially, when external free water intruded into the interface of the asphalt-calcite system, the adsorbed water interacted with free water and seriously declined the water damage resistance of the asphalt mixture with limestone as an aggregate and decreased the durability of the mixtures. The water adsorbed onto the surface of the acid aggregate negatively affected the asphalt-silica interface system and slightly reduced the water damage resistance of the asphalt mixture.

Study of the Self-Healing Performance of Semi-Flexible Pavement Materials Grouted with Engineered Cementitious Composites Mortar based on a Non-Standard Test.

Semi-flexible pavement (SFP) materials, with their characteristics of good high temperature stability, strong durability, and lower cost, are suitable for heavy-duty roads, but their cracking problem has hindered the development and popularization of this kind of pavement to a certain extent. In this study, engineered cementitious composites (ECC) were used to form ECC-SFP materials. The self-healing properties of ECC-SFP materials with three kinds of voids of matrix asphalt mixtures were studied. The test results showed that the fluidity and strength of the ECC mortars met the specification requirements when the water-cement ratio was 0.23 and the ECC fiber dosage was 1-2%. The flexural strength of ECC mortar is better than that of ordinary mortar. The higher the ECC fiber dosage, the higher the flexural strength. Increasing the void of the matrix asphalt mixture and the amount of ECC mortar increased the toughness of the ECC-SFP material, which was seen as an increase of the flow value. Curing conditions are key factor affecting the self-healing properties of ECC mortar and ECC-SFP materials. The self-healing effect of materials in 60 °C water is the best. When an ECC fiber dosage of 1% was used, the HImor of ECC mortar and HImix of ECC-SFP material were 27.5% and 24.8%, respectively. With the addition of ECC material, ECC-SFP material achieved a certain degree of self-healing, but this still needs to be further optimized. Studies of grouting process optimization and increasing the ECC fiber dosage are feasible directions to explore in order to improve the self-healing properties of ECC-SFP materials in the future.

Microstructural Modeling of Rheological Mechanical Response for Asphalt Mixture Using an Image-Based Finite Element Approach.

In this paper, an image-based micromechanical model for an asphalt mixture's rheological mechanical response is introduced. Detailed information on finite element (FE) modeling based on X-ray computed tomography (X-ray CT) is presented. An improved morphological multiscale algorithm was developed to segment the adhesive coarse aggregate images. A classification method to recognize the different classifications of the elemental area for a confining pressure purpose is proposed in this study. Then, the numerical viscoelastic constitutive formulation of asphalt mortar in an FE code was implemented using the simulation software ABAQUS user material subroutine (UMAT). To avoid complex experiments in determining the time-dependent Poisson's ratio directly, numerous attempts were made to indirectly obtain all material properties in the viscoelastic constitutive model. Finally, the image-based FE model incorporated with the viscoelastic asphalt mortar phase and elastic aggregates was used for triaxial compressive test simulations, and a triaxial creep experiment under different working conditions was conducted to identify and validate the proposed finite element approach. The numerical simulation and experimental results indicate that the three-dimensional microstructural numerical model established can effectively analyze the material's rheological mechanical response under the effect of triaxial load within the linear viscoelastic range.

Age-related changes and distribution of T cell markers (CD3 and CD4) and toll-like receptors(TLR2, TLR3,TLR4 and TLR7) in the duck lymphoid organs.

T lymphocytes and Toll-like receptors have been confirmed to have correlation with the ability to resistance to pathogenic challenges and play an important role in duck immune system. However, the information of ontogeny of T lymphocytes and Toll-like receptors is scarcely in duck. Therefore, to address these questions, we report the development and distribution of CD3 and CD4 by immunocytochemistry and the age-related mRNA level of duck T cell markers (CD3 and CD4) and Toll-like receptors (TLR2, TLR3, TLR4 and TLR7) by real time quantitative PCR in duck lymphoid organs (thymus, bursa of Fabricius and spleen). Results indicated that CD3 and CD4 positive cells can be observed in all test organs and partly change in an age-related way. CD4 positive T cell of duck spleen mainly distributed in periarterial lymphatic sheaths and red pulp, not in white pulp. Both of CD3 and CD4 were experienced significant increased wave twice in duck lymphoid organs and T cell dependent cellular immunity of duck may well established until 5 weeks old. The mRNA expression levels of duck TLRs were age and organ dependent, and duck TLR3 and TLR7 were significantly lower abundance in the spleen but higher in thymus and bursa of Fabricius, respectively. This study provide the essential knowledge of the ontogeny of T cells and Toll-like receptors in duck, which may shed lights on the T-cell mediate immunity and innate immunity in duck.

Evaluation of the Protective Efficacy of Poly I:C as an Adjuvant for H9N2 Subtype Avian Influenza Inactivated Vaccine and Its Mechanism of Action in Ducks.

Current commercial H9 avian influenza vaccines cannot provide satisfactory protective immunity against antigenic variant influenza viruses in ducks. Poly I:C, when used as an adjuvant, improves humoral and cellular immunity in many animals but has not been tested in ducks. In this study, we investigated the protective efficacy of Poly I:C as an adjuvant for an inactivated H9N2 Avian influenza vaccine in ducks. We found that an H9N2 vaccine administered with poly I:C (H9-PIC vaccine) induced a significantly more rapid response with higher anti-influenza antibody titers than those of the vaccine alone (H9 vaccine). Moreover, virus shedding was reduced in ducks immunized with the H9-PIC vaccine after challenge with an H9 subtype antigenic variant viruses. IFN-α, IFN-γ, IL-6 and MHC-II mRNA levels were all elevated in ducks receiving the H9-PIC vaccine. In addition, lower expression level of MHC-I may be a reason for inefficient protective ability against heterologous influenza viruses in H9-PIC vaccination of ducks. In conclusion, poly I:C adjuvant enhanced both humoral and cellular immune responses in ducks induced by immunization of inactivated H9N2 vaccine.

Endemic Variation of H9N2 Avian Influenza Virus in China.

Forty-two H9N2 subtype AIV strains were isolated from vaccinated commercial chickens in China from 2012 to 2015. Their HA genes had nucleotide sequence homology from 86.7% to 99.7%, and similarity to the classic vaccine strain was 88.6%-92.6%. A comparison was carried out with published HA genes (410 H9 strains) and whole genomes (306 strains) isolated in China during 2012-2015. Interestingly, 99.1% (448/452) of Chinese H9N2 AIV belonged to lineage h9.4.2, and 98.5% (445/452) of the viruses belonged to h9.4.2.5. Meanwhile, 99.6% (443/445) of lineage 9.4.2.5 viruses had PSRSSR↓GLF instead of PARSSR↓GLF motifs in the HA cleavage sites; 98.2% (444/452) of HA genes showed human receptor binding associated mutation Q226L. A total of 96.8% (337/348) of the viruses had three amino-acid deletions at 63-65 in the NA stalk, associated with enhanced virulence in chickens and mice; 97.1% (338/348) of M2 proteins had the S31N mutation associated with adamantane resistance in humans. Two H9 viruses isolated in this study were highly homologous to the human-origin H9N2 virus reported in 2013. The isolates were divided into four different genotypes (U, S, V, and W). Genotype S was the major one, accounting for 94.8% (330/348). Genotypes V and W were new reassortment genotypes, with genotype W recombined with the PB2 gene originating from the new wild waterfowl-like lineage. According to the cross-HI antibody titer data, HA gene evolution, and isolation history, the isolates were divided into A, B, and C antigenic groups successively. All the antigenic group viruses were found to circulate throughout China. This study emphasizes the importance of updated vaccine and strengthened veterinary biosecurity on poultry farms and trade markets.

Capillary-tube-based micro-plasma system for disinfecting dental biofilm.

PURPOSE: A low-temperature low-energy capillary-tube-based argon micro-plasma system was applied to disinfect Streptococcus mutans-containing biofilm. MATERIALS AND METHODS: The micro-plasma system uses a hollow inner electrode that is ignited by a radio-frequency power supply with a matching network. The energy content was analyzed using optical emission spectroscopy. The micro-plasma-induced effect on a biofilm cultured for 24 or 48 h with a working distance of ≈3 mm at low temperature was evaluated. The morphologies of the treated live/dead bacteria and the produced polysaccharides after micro-plasma treatment were examined. RESULTS: Scanning electron microscopy images and staining results show that most of the S. mutans on the treated biofilm were acutely damaged within a micro-plasma treatment time of 300 s. CONCLUSIONS: The number of living bacteria underneath the treated biofilm greatly decreased with treatment time. The proposed micro-plasma system can thus disinfect S. mutans on/in biofilms.

Nanomechanical probing of the septum and surrounding substances on Streptococcus mutans cells and biofilms.

We report a unique bio-nanomechanical behavior at the septum (Z-ring) of Streptococcus mutans-containing biofilm through in situ measurements obtained by atomic force microscopy. A distinct serrated pattern on the releasing force-displacement curves can only be observed with the use of a sharp nanosized probe tip, and this was found at the septum of S. mutans. Further investigations suggested the serrated patterns could be due to the unfolding of some sub-surface divisome proteins. Seismometer measurements were conducted at the septum by placing an ultra-sensitive atomic force microscope probe on the surface. Unique periodic vibrations were observed at the septum under various biofilm conditions. This finding suggests the possibility of remodeling of the cell wall nanostructure at the septum of S. mutans.