DCs Pulsed with Novel HLA-A2-Restricted CTL Epitopes against Hepatitis C Virus Induced a Broadly Reactive Anti-HCV-Specific T Lymphocyte Response

OBJECTIVE: To determine the capacity of dendritic cells (DCs) loaded with single or multiple-peptide mixtures of novel hepatitis C virus (HCV) epitopes to stimulate HCV-specific cytotoxic T lymphocyte (CTL) effector functions. METHODS: A bioinformatics approach was used to predict HLA-A2-restricted HCV-specific CTL epitopes, and the predicted peptides identified from this screen were synthesized. Subsequent IFN-γ ELISPOT analysis detected the stimulating function of these peptides in peripheral blood mononuclear cells (PBMCs) from both chronic and self-limited HCV infected subjects (subjects exhibiting spontaneous HCV clearance). Mature DCs, derived in vitro from CD14(+) monocytes harvested from the study subjects by incubation with appropriate cytokine cocktails, were loaded with novel peptide or epitope peptide mixtures and co-cultured with autologous T lymphocytes. Granzyme B (GrB) and IFN-γ ELISPOT analysis was used to test for epitope-specific CTL responses. T-cell-derived cytokines contained in the co-cultured supernatant were detected by flow cytometry. RESULTS: We identified 7 novel HLA-A2-restricted HCV-specific CTL epitopes that increased the frequency of IFN-γ-producing T cells compared to other epitopes, as assayed by measuring spot forming cells (SFCs). Two epitopes had the strongest stimulating capability in the self-limited subjects, one found in the E2 and one in the NS2 region of HCV; five epitopes had a strong stimulating capacity in both chronic and self-limited HCV infection, but were stronger in the self-limited subjects. They were distributed in E2, NS2, NS3, NS4, and NS5 regions of HCV, respectively. We also found that mDCs loaded with novel peptide mixtures could significantly increase GrB and IFN-γ SFCs as compared to single peptides, especially in chronic HCV infection subjects. Additionally, we found that DCs pulsed with multiple epitope peptide mixtures induced a Th1-biased immune response. CONCLUSIONS: Seven novel and strongly stimulating HLA-A2-restricted HCV-specific CTL epitopes were identified. Furthermore, DCs loaded with multiple-epitope peptide mixtures induced epitope-specific CTLs responses

Degradation Mechanism of Concrete Subjected to External Sulfate Attack: Comparison of Different Curing Conditions

Sulfate induced degradation of concrete brings great damage to concrete structures in saline or offshore areas. The degradation mechanism of cast-in-situ concrete still remains unclear. This paper investigates the degradation process and corresponding mechanism of cast-in-situ concrete when immersed in sulfate-rich corrosive environments. Concrete samples with different curing conditions were prepared and immersed in sulfate solutions for 12 months to simulate the corrosion of precast and cast-in-situ concrete structures, respectively. Tests regarding the changes of physical, chemical, and mechanical properties of concrete samples were conducted and recorded continuously during the immersion. Micro-structural and mineral methods were performed to analyze the changes of concrete samples after immersion. Results indicate that the corrosion process of cast-in-situ concrete is much faster than the degradation of precast concrete. Chemical attack is the main cause of degradation for both precast and cast-in-situ concrete. Concrete in the environment with higher sulfate concentration suffers more severe degradation. The water/cement ratio has a significant influence on the durability of concrete. A lower water/cement ratio results in obviously better resistance against sulfate attack for both precast and cast-in-situ concrete

Geometric Parameters Calibration of Focused Light Field Camera Based on Edge Spread Information Fitting

In this paper, a novel method based on edge spread information fitting (ESIF) is proposed to accurately calibrate the geometric parameters of a focused light field camera. A focused light field camera with flexible adjustment of spatial resolution and angular resolution is designed and built to capture the four-dimensional light field information of the scenes, and the geometric relationship between the focus plane of the camera and its internal parameters is derived to establish and simplify the calibration model. After that, a new algorithm based on sub-pixel edge fitting is designed to accurately detect corners, and the minimum corner size can be calculated to confirm the focus plane. In the simulation experiments, the error is 0.083% between the ground truth and the calibration result. The physical experiments show that our method is effective and reliable for the geometric calibration of a focused light field camera. Our method cleverly utilizes the special imaging geometric relationship of the focused light field camera to ensure the better calibration accuracy, which makes the calibration process more reliable

Study on the Disintegration Characteristics and Mechanism of Modified Dispersive Soil Based on the C-S-H Synthesis Principle

Since dispersive soil has the characteristic of dispersing and disappearing when making contact with water, lime, fly ash, and cement are often used to modify dispersive soil in engineering. This often causes environmental pollution. Current studies tend to search for environmentally friendly modification methods. A new Ca−Si-modified dispersive soil method was proposed based on the synthesis principle of calcium silicate hydrate (C-S-H). Pinhole, mud ball, dispersion, and disintegration tests were used to investigate the modification effect and physical, chemical, and microscopic tests were used to investigate the mechanism. The results show that the dispersivity of soil can be eliminated by using 0.8% CaO or 4% nanosilica. The dispersivity of Ca−Si-treated soil can be eliminated at a 0.5 C/S and a 1% solid dosage. The disintegration characteristics of CaO-modified and Ca−Si-modified soils are different from those of dispersive soil. The final disintegration time of CaO-modified soil was shortened, and the disintegration rate was stable. The Ca−Si-modified soil had the best disintegration resistance at a 0.5 C/S and a 2% solid dosage. With the increase in the C/S, the disintegration resistance was reduced. The mechanism of Ca−Si-modified soil includes reducing the pH and exchangeable sodium percentage and generating calcium silicate hydrate cement. The results show that the Ca−Si treatment method based on the C-S-H synthesis principle can effectively eliminate soil dispersivity and improve disintegration resistance, which can theoretically support the reduction in contamination caused by traditional materials and improve engineering safety

Study on the Disintegration Characteristics and Mechanism of Modified Dispersive Soil Based on the C-S-H Synthesis Principle

Since dispersive soil has the characteristic of dispersing and disappearing when making contact with water, lime, fly ash, and cement are often used to modify dispersive soil in engineering. This often causes environmental pollution. Current studies tend to search for environmentally friendly modification methods. A new Ca−Si-modified dispersive soil method was proposed based on the synthesis principle of calcium silicate hydrate (C-S-H). Pinhole, mud ball, dispersion, and disintegration tests were used to investigate the modification effect and physical, chemical, and microscopic tests were used to investigate the mechanism. The results show that the dispersivity of soil can be eliminated by using 0.8% CaO or 4% nanosilica. The dispersivity of Ca−Si-treated soil can be eliminated at a 0.5 C/S and a 1% solid dosage. The disintegration characteristics of CaO-modified and Ca−Si-modified soils are different from those of dispersive soil. The final disintegration time of CaO-modified soil was shortened, and the disintegration rate was stable. The Ca−Si-modified soil had the best disintegration resistance at a 0.5 C/S and a 2% solid dosage. With the increase in the C/S, the disintegration resistance was reduced. The mechanism of Ca−Si-modified soil includes reducing the pH and exchangeable sodium percentage and generating calcium silicate hydrate cement. The results show that the Ca−Si treatment method based on the C-S-H synthesis principle can effectively eliminate soil dispersivity and improve disintegration resistance, which can theoretically support the reduction in contamination caused by traditional materials and improve engineering safety

Mechanical Characterization and Constitutive Modeling of Nano-Stabilized Soil under Uniaxial Compression

The stress–strain constitutive model under uniaxial compression is a basic element and important characterization method for determining physical and mechanical properties in cement-based materials research. In this study, a stress–strain constitutive model under uniaxial compression was established, which was based on a new nano-stabilized soil (NSS) through typical mechanical tests and constitutive relationship research. The results indicate that the unconfined compressive strength (UCS) of the nano-stabilized soil was enhanced with the increase in curing period and nano-stabilizer dosage, and that the strength growth rate reaches the maximum at a 12% dosage in the tested samples. The UCS of NSS under a 12% dosage is about 10~15% higher than that of ordinary stabilized soil (SS) without nano doping, and 25~40% higher compared with grade 42.5 cement-soil. The established constitutive model could accurately describe the linear-elastic and elastic-plastic deformation characteristics of NSS under uniaxial compression, which will be conducive to revealing the curve variation law of the stress–strain process. The research results could provide scientific support for the theoretical innovation and engineering application of green environmental protection materials

Mechanical Characterization and Constitutive Modeling of Nano-Stabilized Soil under Uniaxial Compression

The stress–strain constitutive model under uniaxial compression is a basic element and important characterization method for determining physical and mechanical properties in cement-based materials research. In this study, a stress–strain constitutive model under uniaxial compression was established, which was based on a new nano-stabilized soil (NSS) through typical mechanical tests and constitutive relationship research. The results indicate that the unconfined compressive strength (UCS) of the nano-stabilized soil was enhanced with the increase in curing period and nano-stabilizer dosage, and that the strength growth rate reaches the maximum at a 12% dosage in the tested samples. The UCS of NSS under a 12% dosage is about 10~15% higher than that of ordinary stabilized soil (SS) without nano doping, and 25~40% higher compared with grade 42.5 cement-soil. The established constitutive model could accurately describe the linear-elastic and elastic-plastic deformation characteristics of NSS under uniaxial compression, which will be conducive to revealing the curve variation law of the stress–strain process. The research results could provide scientific support for the theoretical innovation and engineering application of green environmental protection materials

Microphase Separation and High Ionic Conductivity at High Temperatures of Lithium Salt-Doped Amphiphilic Alternating Copolymer Brush with Rigid Side Chains

An amphiphilic alternating copolymer brush (AACPB), poly­{(styrene-<i>g</i>-poly­(ethylene oxide))-<i>alt</i>-(maleimide-<i>g</i>-poly­{2,5-bis­[(4-methoxy­phenyl)­oxycarbonyl]­styrene})}­(P­{(St-<i>g</i>-PEO)-<i>alt</i>-(MI-<i>g</i>-PMPCS)}), was synthesized by alternating copolymerization of styrene-terminated poly­(ethylene oxide) (St-PEO) and maleimide-terminated poly­{2,5-bis­[(4-methoxy­phenyl)-oxy­carbonyl]­styrene} (MI-PMPCS) macromonomers using the “grafting through” strategy. ¹H NMR and gel permeation chromatography coupled with multiangle laser light scattering were used to determine the molecular characteristics of AACPBs. Although these AACPBs cannot microphase separate with thermal and solvent annealing methods, they can form lamellar structures by doping a lithium salt. This is a first report on lithium salt-induced microphase separation of AACPBs, and the lithium salt-doped AACPBs can serve as solid electrolytes for the transport of lithium ion. For the same AACPB, the ionic conductivity (σ) increases with increasing doping ratio. In addition, σ values of different AACPBs with the same doping ratio become higher for shorter PMPCS side chains. The σ value of the lithium salt-doped AACPB increases with increasing temperature in the range of 25–240 °C, and σ is 1.79 × 10^–4 S/cm at 240 °C. The relatively high σ values of the lithium-doped AACPBs at high temperatures benefit from the rigid PMPCS side chain and the AACPB architecture. The lithium salt-doped AACPBs have the potential to serve as solid electrolytes in high-temperature lithium ion batteries