Search

In two-dimensional materials, structure difference induces the difference in phonon dispersions, leading to the anisotropy of in-plane thermal transport. Here, we report an exceptional case in layered PdSe2, where the bonding, force constants, and lattice constants are nearly-equal along the in-plane crystallographic axis directions. The phonon dispersions show significant differences between the Gamma-X and Gamma-Y directions, leading to the anisotropy of in-plane thermal conductivity with a ratio up to 1.8. Such anisotropy is not only unexpected in equilaterally structured (in-plane) materials but also comparable to the record in the non-equilaterally structured material reported to date. By combining inelastic X-ray scattering and first-principles calculations, we attribute such anisotropy to the low-energy phonons along Gamma-X, in particular, their lower group velocities and "avoided-crossing" behavior. The different bucking structures between a- (zigzag-type) and b-axis (flat-type) are mainly responsible for the unique phonon dynamics properties of PdSe2. The present results illustrate the unusual thermal conduction mechanism of the equilaterally structured materials and provide valuable insights on thermal management in electronic devices., Comment: 16 figures, 2 tables

We study the problem of stochastic bandits with adversarial corruptions in the cooperative multi-agent setting, where $V$ agents interact with a common $K$-armed bandit problem, and each pair of agents can communicate with each other to expedite the learning process. In the problem, the rewards are independently sampled from distributions across all agents and rounds, but they may be corrupted by an adversary. Our goal is to minimize both the overall regret and communication cost across all agents. We first show that an additive term of corruption is unavoidable for any algorithm in this problem. Then, we propose a new algorithm that is agnostic to the level of corruption. Our algorithm not only achieves near-optimal regret in the stochastic setting, but also obtains a regret with an additive term of corruption in the corrupted setting, while maintaining efficient communication. The algorithm is also applicable for the single-agent corruption problem, and achieves a high probability regret that removes the multiplicative dependence of $K$ on corruption level. Our result of the single-agent case resolves an open question from Gupta et al. [2019].

profiled side channel analysis is considered as the most powerful side channel analysis by obtaining a copy of the attacking targe. With the population of deep learning technology in side channel analysis, Benadjila. R et al. proposed a profiled side attacks strategy based on convolutional neural network for AES with first-order mask countermeasure. However, this paper only implements training analysis while keeping the number of convolutional layers in the convolution module consistent and without trying to use common convolution kernel sizes. This paper conducts parameter selection experiments on the number of convolutional layers under the convolution module in the convolutional neural network and the size of the commonly used convolution kernel, and proposes a new optimized network model.As a result, this model can find out the correct key within 54 traces, which is better than the 180 traces record of Benadjila. R et al.

Earth pressure is the most important type of load acting on the supporting structure of a foundation pit, and it is also a key factor in the design of foundation pit supporting. However, in engineering practice, the calculated value differs greatly from the actual value, which puzzles many engineers. This paper analyzes the field measured data of the earth pressure of the foundation pit in Minghucheng (Jinan city), and compares the calculated values of the Rankine active earth pressure and the passive earth pressure theory. The analysis finds that: (1) The measured value is between the active earth pressure and the passive earth pressure, and as the excavation of the foundation pit and the inward displacement of the supporting structure, the measured earth pressure value becomes smaller and approaches the active earth pressure. (2) When the pre-stressed anchors is applied, due to the fastening effect of the anchors, the earth pressure behind the supporting pile has a tendency to increase. (3) The theoretical value of Rankine’s active earth pressure in the soil-rock combination is obviously lower than the measured values.

This paper analyzes the effect mechanism of pipe jacking on the surrounding soil disturbance during the construction of subway station pipe jacking, and uses MIDAS GTS/NX to numerically simulate the impact of pipe jacking on the surface and internal forces of the building. During the construction, the influence of the surrounding soil disturbance and the existing railway track was studied, and the law of the influence on the surrounding buildings and the ground surface during the pipe jacking construction process was analyzed and studied.

Surface nuclear magnetic resonance (surface NMR) has up to now rarely been applied to 3D subsurface modeling. Inversion approaches currently in use are smooth inversion techniques that are not useful for identifying sharp geologic boundaries. Although they are already computationally expensive, the resulting models are restricted to imaging the subsurface water content distribution and do not deliver relaxation times [Formula: see text] based on the QT inversion scheme established elsewhere. We have developed a method of 3D block QT inversion that uses horizontal smoothness constraints to resolve sharp boundaries in the vertical direction and the distributions of the water content and relaxation time [Formula: see text]. We have improved the computational efficiency, i.e., the ability to perform the inversion using a common desktop computer, by gating the surface NMR data, reducing the model space to monoexponential decays within the subsurface bodies, and inverting based on blocklike structures instead of smooth distributions. We have developed a synthetic study to assess the effectiveness of our block QT inversion technique in imaging 3D water content distributions, and we compared the results with those of a smooth inversion. Furthermore, we evaluated results from a field survey conducted on the frozen surface of an artificial lake. We found that our block QT inversion approach provides results that are superior to those of smooth inversion and consistent with the available construction plan of the lake. We expect that 3D block QT inversion will be a useful approach also in other geologic settings, such as buried valleys, because it overcomes the current limitations of applying 3D surface NMR inversion.

In this study, the monocrystalline silicon (c-Si) solar cell irradiated by 100 KeV proton beams at various fluences is investigated. A one-dimensional two-layer carrier density wave model has been developed to estimate the minority carrier lifetime of n-region and p-region of the non-irradiated c-Si solar cell by best fitting with the experimental photocarrier radiometry (PCR) signal (the amplitude and the phase). Furthermore, the lifetime is used to determine the initial defect density of the quasi-neutral region (QNR) of the solar cell to predict its I–V characteristics. The theoretically predicted short-circuit current density (Jsc), and open-circuit voltage (Voc) of the non-irradiated samples are in good agreement with experiment. Then a three-region defect distribution model for the c-Si solar cell irradiated by proton beams is carried out to describe the defect density distribution according to Monte Carlo simulation results and the initial defect density of the non-irradiated sample. Finally, we find that the electrical measurements of Jsc and Voc of the solar cells irradiated at different fluences using 100 KeV proton beams are consistent with the PCR predicting results.

An inverse analysis methodology is developed to simultaneously identify the thermal diffusivities and subsurface defect of carbon fiber reinforced polymer (CFRP) laminate through lock-in thermographic phase (LITP) profile reconstruction. A hybrid algorithm that combines simulation annealing algorithm (SA) and Nelder–Mead simplex search method (NM) is proposed to minimize the objective function constructed by LITP profile for determination of the thermal diffusivities ( α x and α z ) and subsurface defect characteristics (size D and depth H D ). For the hybrid method, SA is used to find a better feasible initial-guessed solution for NM. Numerical examples show that LITP has the merit of identifying the thermal diffusivities of CFRP laminate by inverse analysis. In comparison with SA and NM, respectively, the hybrid method can be converged to yield good estimates faster and more efficiently. Experimental and simulation LITP of defective regions are used to determine the thermal diffusivities and the size and depth of subsurface defect. The results show that the estimated thermal diffusivities and the size and depth of defect are in good agreement with the reference values, and the relative deviations are less than 5%. Nevertheless, this approach can only be applied for the determination of thermal diffusivities of CFRP laminate with subsurface defect.

In this work, an extension laser beam was used as heating source to evaluate the composite material by active thermographic method. In particular, a series of carbon-fiber-reinforced polymer (CFRP) specimens with various depth and sizes of flat-bottom holes (FBH) were inspected using lock-in thermography (LIT). The quantitative LIT phase was employed to identification the subsurface defect using the phase decision threshold (PDT, a phase deference between defective area and the sound one), and then the detectable and undetectable defects were expressed as 1 and 0 (hit/miss data), respectively. The POD curves of continuous phase response data and the hit/miss data processing were used for estimation the detection capability and reliability of LIT phase image for NDI&E of CFRP composites, and the effects of PDT value and modulation frequency on POD curves were compared.

An inverse heat transfer approach is developed to characterize the size and depth of subsurface defects in CFRP composite materials through the reconstruction phase profile of lock-in thermography (LIT) obtained by finite element simulation. This work mainly focuses on the application of hybrid method that integrates simulation annealing algorithm (SA) and Nelder–Mead simplex search method (NM) for determination of the sizes and depths of subsurface defects within the CFRP laminate materials. For this purpose, an 808 nm laser is used for imposing a modulated heat excitation on the CFRP laminate specimen, and the thermal images are collected using an infrared camera. The hybrid method is employed to find the optimal solutions of the objective or cost function constructed by phase profile of LIT between an experimental configuration and numerical solution for a CFRP specimen. The experimental results show that the size and depth of subsurface defects are effectively obtained through inverse solving the constructed objective or cost function by the hybrid method. The estimated maximum errors for the size and depth are less than 5% and 4% for given subsurface defects by the proposed method, respectively.

Edge detection is an important technology in image segmentation, feature extraction and other digital image processing areas. Boundary contains a wealth of information in the image, so to extract defects’ edges in infrared images effectively enables the identification of defects’ geometric features. This paper analyzed the detection effect of classic edge detection operators, and proposed fuzzy C-means (FCM) clustering-Canny operator algorithm to achieve defects’ edges in the infrared images. Results show that the proposed algorithm has better effect than the classic edge detection operators, which can identify the defects’ geometric feature much more completely and clearly. The defects’ diameters have been calculated based on the image edge detection results.

The pulsed thermographic technique was used to detect flat-bottomed hole defects in CFRP sheet. Pulsed phase thermography (PPT) was used to extract the characteristic information of the thermal wave signal generated by thermal pulse. The difference of the phases between the sound and defective areas were analyzed. The defects’ edges were extracted by Fuzzy C-Means clustering algorithm.

According to the 2030 Agenda for Sustainable Development, the sustainable development goal 11 is to “make cities and human settlement inclusive, safe, resilient and sustainable”. China has been making great effort in this respect. With the advancement in science and technology, the concepts of green development, environmental friendliness, and fair development are gradually moving from theories to practices, guiding the construction and development of sustainable cities in China. Over the past 40 years of reform and opening up, the overall process of China’s construction of sustainable cities and development can be divided into three stages: the initial practice stage (1986–2000), the stage focusing on transformation (2001–2012), and the stage emphasizing coordinated development and social fairness (2012 to present). During the process, China has proposed and carried out a series of pilot demonstrations of sustainable cities, eco-cities, garden cities, low-carbon cities, livable cities, resilient cities, sanitary cities, sponge cities, and circular economy cities. It has achieved remarkable results with valuable experience; meanwhile, it still faces many challenges considering the current practices. With the integration of planning for the national economy and social development, rural and urban development, land use, and other aspects, as well as the implementation of the 2030 Agenda for Sustainable Development, sustainable urban practices in China will receive more policy support and effective administrative support. As the largest developing country in the world, China’s practice in sustainable urban development undoubtedly has a broad demonstration effect and can contribute to global sustainable development.

An investigation on SiC coated carbon–carbon (C/C) composite plates has been undertaken by pulsed thermography. The heat transfer model has been built and the finite element method (FEM) is applied to solve the thermal model. The simulation results show that defects with DA/DP smaller than one can hardly be detected by an infrared camera with the sensitivity of 0.02 °C. Certificated experiments were performed on the built pulsed thermography system. The thermal wave signals have been processed by subtracting background image method (SBIM), pulsed phase thermography (PPT), and temperature–time logarithm fitting method (TtLFM). The limit DA/DP of defects in SiC coated C/C composite plates with the thickness of 6 mm that can be detected by pulsed thermography with the presented signal analysis algorithms has been obtained.

Active infrared thermographic technique was used as a non-destructive inspection (NDI) tool for carbon–carbon (C/C) composite with subsurface defects. A serial of representative carbon–carbon composite test samples, consisting of cutouts and cracks as defects were investigated experimentally and analyzed using finite element method (FEM). Both transient pulsed thermography and lock-in thermography technique were investigated. The capability of two techniques to detect subsurface defects of C/C composite and to provide information about the location of defect was analyzed. Results indicate that active thermographic technique is available for the subsurface defect detection of carbon–carbon composite.

An investigation into the effect of size on the quantitative estimation of defect depth in a SiC coated carbon–carbon (C/C) composite has been undertaken by lock-in thermography. A dedicated 3-D thermal modeling has been introduced, and an efficient numerical algorithm based on finite-difference splitting method in time domain (FDSM-TD) is applied to solve the thermal model. The heat transfer partial differential equation (PDE) and mathematic morphological algorithms are used to filter the phase angle data noise. The diameter of a defect had an appreciable effect on the observed phase angle which consequently has significant implications with regard to estimating the defect depth. Phase angle contrast measurements for a range of defects in a 6.0 mm SiC coated C/C composite specimen indicate that an optimal excitation frequency of 0.525 Hz is available for defect detection. Results obtained with an excitation frequency of 0.525 Hz are used to discuss the limitations of determining the defect size and depth.

This paper describes the quantitative analysis of the boundary, location and depth of subsurface defects by lock-in thermography. The phase difference between defective areas and non-defective areas illustrates the qualitative analysis of the boundary and the location of the subsurface defect. In order to accurately estimate the size, location and depth of the defects, the phase is normalised, the heat transfer partial differential equation (PDE) model is used to filter the noise of normalised phase image and the differential normalised phase profile is employed to determine the boundary and location of the defect. The profile of the differential normalised phase distribution has maximum, minimum and zero points that help to quantitatively determine the boundary and location of the subsurface defect. An artificial neural network (ANN) is proposed to determine the depth of the subsurface defect. Experimental results for a steel plate, a carbon fibre-reinforced polymer (CFRP) sheet–foam sandwich, and honeycomb structure composites with artificial subsurface defects show good agreement with the actual values.

A novel non-destructive ultrasound infrared lock-in thermography (ULT) testing method was presented in order to detect metal specimens with subsurface contacting interfacial defects. An experimental platform was built. Experiments had been carried out to Q235 plates with different testing parameters. The testing effect of amplitude and phase images was analyzed, and the relation between amplitude difference, phase difference, signal-to-noise ratio and modulation frequency was discussed. An adaptive neuro-fuzzy inference system model was built to forecast the depth of defects.

By investigating the influence of the difference of refractive index between core and cladding (nco-ncl), normalized frequency (V ) and core radius (?) on both the intramodal and intermodal nonlinear coefficients (NCs) respectively, we design a novel weakly-coupled four-mode fiber with low nonlinearity. In general, under the premise of ensuring the low NCs between two non-degenerate modes, this design can reduce the intermodal NCs (< 0.5 W-1 \cdot km-1) between two degenerate modes and optimizes the parameters of differential group delays (DGDs) and chromatic dispersion. The optimized few mode fiber (FMF) is eligible for transmission and mode de-multiplexing in the receiver.

PurposeGreen machining is becoming increasingly more popular due to concern regarding the safety of the environment and human health. The important implementation of stricter Environmental Protection Agency regulations associated with the use of ample amount of coolants and lubricants has led to this study on a new green machining technology with application of water vapor as coolants and lubricants in cutting Ni‐based superalloys and titanium alloy Ti‐6Al‐4V with uncoated carbide inserts (ISO Type K10). The purpose of this paper is to show that machining technology with application of water vapour could be an economical and environmentally compatible lubrication technique for machining difficult‐cut‐materials.Design/methodology/approachIn this paper, the effect of water vapor applications in machining difficult‐cut‐materials have been investigated in detail, the cutting force, the chip deformation coefficient, the rake face wear and the width of tool flank land VB have been examined and analyzed, and a new green cutting technology is researched to machining Ni base superalloys and Ti‐6Al‐4V difficult‐cut‐materials.FindingsThe cutting force of machining Ni base superalloys and Ti‐6Al‐4V was affected by direct water vapor application, being lower than dry cutting and wet machining for all machining conditions; the Λh is the smallest with applications of water vapor as coolants and lubricants compared to dry cutting, pure water and oil water emulsion conditions the tool life extended by about six times than dry cutting, about four times than oil water emulsions at low cutting speed (νcνc>100 m/min) during machining Ti‐6Al‐4V with application of water vapor direct into the cutting zone.Originality/valueThe green cutting technology which applies water vapor as coolants and lubricants advocates a new method for machining difficult‐cut‐materials (Ni base superalloys and Ti‐6Al‐4V) without any environment pollution and operator health problem because the cutting force and chip deformation coefficient are reduced, the tool life is extended, and the tool flank wear can be decreased with applications of water vapor as coolants and lubricants to alleviate the adhering and diffusion wear compared to wet cutting and dry cutting.

Water vapor is a new type of environmental friendly coolant and lubricant. In this study, the friction test was carried out by using the water vapor as lubricant, and the friction pair was made of cement carbide K20 and ANSI 304 stainless steel. In order to study the lubricating action of water vapor as coolant and lubricant in cutting ANSI 304 stainless steel, experiments were carried out with K20 cutter. Through chemical state analyses of elements on tool–chip interface by means of XPS and Gibbs free energy calculation, the chemical reaction process was discussed between water molecule, oxygen atom and fresh tool–chip interface. Experimental results showed that an adsorption film and a tribo-chemical reaction film are formed on the tool–chip surfaces due to its excellent penetration performance and ability to form boundary lubrication layer. The multi-dimensional metal-oxide formed during the reaction weaken the mutual action between tool bulk material and chip. The cutting force and tool flank wear are reduced rapidly, and hence the tool wear is reduced about 50–75% compared with dry machining.

Eutrophication and algal blooms are the most serious environmental problems in the world, and biological tools, especially the allelopathic inhibitory effects of aquatic macrophytes on phytoplankton growth have been receiving world-wide attention. In our experiments, the allelopathic inhibitory effect of Myriophyllum aquaticum culture water on Microcystis aeruginosa and its eco-physiological mechanism were investigated by initial addition assays and continuous addition assays. The results showed that the growth of M. aeruginosa was markedly inhibited by M. aquaticum culture water. Compared with initial addition assays, M. aquaticum exhibited stronger inhibitory potential on M. aeruginosa by continuous addition assays, indicating that allelopathic compounds might be excreted continuously by M. aquaticum , and the inhibitory effects would be cumulative. We also found that the relative content of chlorophyll a (Chl a), phycocyanin (PC) and allophycocyanin (APC) of M. aeruginosa decreased to 52.7%, 15.3% and 7.6% respectively after being treated by M. aquaticum culture water for 5 days, and phycobiliprotein (especially APC) decreased more than Chl a. These results suggest that the phycobiliprotein would be the target of allelopathic inhibition of M. aquaticum on M. aeruginosa , and a new macrophyte to control cyanobacterial blooms would be found.

PurposeAt the present time, green cutting has become the focus of attention in ecological and environmental protection. Water vapor is cheap, pollution‐free and eco‐friendly. Therefore, it is a good and economical coolant and lubricant. To find the discipline of nozzle diameter, the parameters of water vapor jet flow and cooling distance influence on its lubricating action effect, experiments were carried out in which YT15 (P10 type in ISO) tool was used in cutting C45 steel.Design/methodology/approachThe vapor generator and vapor feed system are manufactured. The temperature and velocity distribution of water vapor jet flow influences the velocity such that water vapor fills up the capillaries and forms the boundary lubricating film layer in the cutting zone, and the temperature and velocity distribution of the vapor jet flow section contains the effective area for the lubricating effect. Through the temperature distribution measured, the empirical formula of temperature distribution is obtained and simulated by Matlab. The turning experiment was carried out according to quantity in cutting υc=45, 60, 75, 90, 105, 120 mm/min, f=0.1 ∼ 0.3 mm/rev, ap=1, 2, 3, 3.5 mm and the jet flow parameters were changed, respectively.FindingsIt was found that: significant decrease of cutting force can be realized with reduced nozzle diameter, increased the sett pressure and shortened the cooling distance. However, reduced to a certain extent it will lead to the increase of the cutting force. The optimal nozzle diameter is 2 mm for the best lubricating effect. The effect on cutting force of the cooling distance is much better than the setting pressure. Significant decrease of friction coefficient of tool‐chip can be realized with reduced nozzle diameter. However, reduced to a certain extent it will lead to the increase of friction coefficient. Significant thinness of chips can be realized by reducing nozzle diameter. But if the diameter is reduced to a certain degree, chips will be thickened. Increased set pressure and shortened cooling distance can both reduce chip thickness, resulting in reduction of chip deformation coefficient. Since water vapor has the advantage of being cheap, pollution‐free and harmless, and there is no need for disposal and recycling, it is ideal for cooling and lubricating technology in green cutting.Originality/valueThe paper establishes the discipline of nozzle diameter, the parameters of water vapor jet flow and cooling distance influence on its lubricating action effect.

What mechanism that determines microglia accomplishing destructive or constructive role in CNS remains nebulous. We report here that intracranial priming and rechallenging with Toxoplasma gondii in mice elicit neurotoxic CCR9+Irg1+ (immunoresponsive gene 1) microglia, which render resistance to apoptosis and produce a high level of TNF-α; priming and rechallenging with lymphocytic choriomeningitis virus elicit neurosupportive CXCR3+Irg1− microglia, which are sensitive to apoptosis and produce a high level of IL-10 and TGF-β. Administration of CCR9 and/or Irg1 small interfering RNA alters the frequency and functional profiles of neurotoxic CCR9+Irg1+ and neurosupportive CXCR3+Irg1− microglia in vivo. Moreover, by using a series of different neurotropic pathogens, including intracellular parasites, chronic virus, bacteria, toxic substances, and CNS injury to intracranially prime and subsequent rechallenge mice, the bi-directional elicitation of microglia has been confirmed as neurotoxic CCR9+Irg1+ and neurosupportive CXCR3+Irg1− cells in these mouse models. These data suggest that there exist two different types of microglia, providing with a novel insight into microglial involvement in neurodegenerative and neuroinflammatory pathogenesis such as Alzheimer’s disease and AIDS dementia.

The DNA fragment encoding matureMycobacterium tuberculosis major secretory protein Ag85B was inserted into thePichia pastoris secretory expression vector pHBM905A, under the control of theAOX1 promoter. The recombinant plasmid pHBM905A-85B linearized bySal I was introduced intoPichia pastoris strain GS115 by PEG1000 transformation method. After phenotype screening and PCR identification, the resulting GS115-pHBM905A-85B strain was cultivated and induced with methanol. The recombinant Ag85B protein in secreted form was attained with molecular weight of 35×103 approximately detected by SDS-PAGE and Western blot. ELISA experiment proved that the protein had good antigen specificity. Secretory expression of recombinantM. tuberculosis Ag85B inP. pastoris will open a door to mass production of the protein in heterologous host and allow ready evaluation of its immunological function.

We investigated CD4 and CD8 double-positive thymocytes, CD4+ T cells from typical patients with T-cell lineage acute lymphocytic leukemia (T-ALL) and T cell lineage chronic lymphocytic leukemia (T-CLL), and MOLT4 T cells in terms of CC chemokine ligand 25 (CCL25) functions of induction of resistance to tumor necrosis factor α (TNF-α)–mediated apoptosis. We found that CCL25 selectively enhanced resistance to TNF-α–mediated apoptosis in T-ALL and T-CLL CD4+ T cells as well as in MOLT4 T cells, but CD4 and CD8 double-positive thymocytes did not. One member protein of the inhibitor of apoptosis protein (IAP) family, Livin, was selectively expressed in the malignant cells at higher levels, particularly in T-ALL CD4+ T cells, in comparison with the expression in CD4 and CD8 double-positive thymocytes. After stimulation with CCL25 and apoptotic induction with TNF-α, the expression levels of Livin in these malignant cells were significantly increased. CCL25/thymus-expressed chemokine (TECK), by means of CC chemokine receptor 9 (CCR9) ligation, selectively activated Livin to enhance resistance to TNF-α–mediated apoptosis in c-jun-NH2-kinase 1 (JNK1) kinase-dependent manner. These findings suggested differential functions of CCR9/CCL25 in distinct types of cells. CD4 and CD8 double-positive thymocytes used CCR9/CCL25 for migration, homing, development, maturation, selection, cell homeostasis, whereas malignant cells, particularly T-ALL CD4+ T cells, used CCR9/CCL25 for infiltration, resistance to apoptosis, and inappropriate proliferation.

Chemokine receptors are important in the entry of leucocytes into the inflammatory sites of systemic lupus erythematosus (SLE). CCR7(+) and CCR7(-) memory T cells exert different functions in homing, cytokine production and cytotoxicity. To determine whether differential expression and functions of the CCR7 occur in SLE patients, we examined CCR3, CCR4, CCR5, CCR7 and CCR9 on CD4(+) and CD8(+) T cells from normal and SLE subjects. Flow cytometry, real-time quantitative reverse transcription polymerase chain reactions and Northern blotting were used to detect the expression of chemokine receptors and cytokines; a chemotaxis assay was used to detect their functions. CD4(+) T-cell stimulation with syngeneic CCR7(+) CD8(+) CD45RO(+) T cells and dendritic cells (including transwell chambers) was used to induce cytokine expression. We demonstrated that CCR7 was selectively, frequently and functionally expressed on CD8(+) (94.8%) but not on CD4(+) (16.1%) T cells from patients with active SLE, whereas this phenomenon was not seen in normal subjects and in those whose SLE was inactive. CCR7(+) CD8(+) CD45RO(+) memory T cells from patients with active SLE, themselves T helper type 2 (Th2) biased, were inducers of Th2 bias in CD4(+) T cells in a cell-cell contact manner in vitro, meanwhile, the cells from both normal subjects and those whose SLE was inactive drove CD4(+) T cells into a regulatory T-cell-derived cytokine pattern. Our findings might provide new clues to understanding the functions of CCR7(+) CD8(+) CD45RO(+)'central' memory T cells in autoimmune diseases (such as SLE). We suggest that in the case of active SLE, CCR7(+) central memory T cells were able to enter peripheral blood and inflammatory sites from secondary lymphoid organs, were continuously expressing CCR7, and interacted with dendritic cells and functioned as CCR7(-)'effector' memory T cells, which were described in normal humans.

CXCR3, predominately expressed on memory/activated T cells, is a receptor for both interferon-gamma inducible protein-10/CXC ligand 10 (CXCL10) and monokine induced by interferon-gamma/CXCL9. We reported here that CXCR3 was highly up-regulated on infiltrating eosinophils in Schistosoma japonicum egg-induced granuloma in the mouse liver. It was also highly and functionally up-regulated on peritoneal exudate eosinophils in mice infected with S. japonicum. The phenomena were demonstrated at protein and mRNA levels using immunohisto- and immunocytochemistry evaluation of biopsy, flow cytometry and real-time quantitative reverse transcriptase-polymerase chain reaction technique, and verified by Northern blotting and chemotaxis assay in vitro. We also found that CCR3 expression on the infiltrating and peritoneal exudate cells was significantly decreased, CXCR4 expression was unchanged during the 42-day period of infection. We screened mRNA expression levels of the all known chemokine receptors in purified peritoneal exudate eosinophils and liver granuloma dominated by eosinophils. CXCR3 was highly and functionally up-regulated on peritoneal exudate eosinophils in mice infected with S. japonicum, meanwhile CCR3 was significantly and functionally down-regulated in these cells. The findings could lead to a better understanding of the chemokine receptor expression pattern of eosinophils at inflamed tissue sites caused by parasites. These could be also crucial for establishing a therapeutic strategy for eosinophilic inflammation via intervention in chemokine actions.

To the human race, the earth, and the universe, which have been in existence for millions of years, twenty years is a short period of time; but to a person, it is an important period of time during which an infant can become a young man. Time flies. Young or not, looking back at your life after twenty years is like recalling a song about life which sings: "Time runs fast like a white horse, it'll pass you by unnoticed if you do not quicken your steps …"

This paper systematically presents the information about a sustainable city and the process of putting forward, developing and evolving the concept, and it provides an analysis of some current main views in the studies of sustainable cities. In this paper, it is argued that the construction of a sustainable city should not be carried out simply by bringing the concept of sustainable development down to the city level; sustainable development should be more materialized, scenario focused, and localized at the city level, and it should be internalized into the various dimensions of the construction of a city at the special temporal and spatial scales of a city. Based on literature reviews, this paper holds that there are three drawbacks in the current understanding of a sustainable city, mainly including: First, emphasis is placed on the internal equilibrium of a city, but no attention is paid to the negative environmental externalities of other cities or areas and the compensation for them; second, the ultimate goal of sustainable development — achieving equilibrium — is excessively stressed, while the embodiment of the stages of development and regional differences in the goal of sustainable development is overlooked; third, the form of the city is a key indicator for building a sustainable city, but this indicator is basically unavailable in the current definitions of sustainable cities. The definition and theory of a sustainable city should fully reflect the temporal and spatial nodes of differentiation in a sustainable city and the dynamic relationship of equilibrium between the systems of a city and the surrounding areas; its definition and theory should also realistically address the urban needs and the practice of the sustainable development of a city. Based on a comprehensive analysis, this paper stresses that a sustainable city is a city in which the form of the city is scientifically designed in line with a certain social and economic development level, and environmental conditions in order to optimize the internal and external functions, improve the system of urban governance, achieve a dynamic equilibrium among economic development, environmental safety, resource utilization and social equity, continuously enhance its capability for coping with risks, make it more livable, and provide positive externalities in perspectives of economy, environment and social governance for other cities.

In this letter, a nonlinear photothermal characteristic of dental tissues has been verified by photothermal radiometry at a given frequency with changing of the laser intensity. Subsequently, the high-frequency heterodyne lock-in thermography (HeLIT) scheme has been introduced to overcome shortages of the low infrared camera frame rate and the poor signal-noise ratio. The smooth surface tooth was artificially demineralized at a different time, and then it was detected by HeLIT, Results illustrated that the phase delay increases with the extension of the demineralized treatment time. The comparison experiments between HeLIT and the homodyne lock-in thermography for detecting artificial caries were carried out. Experimental results illustrated that the HeLIT has the merits of high sensitivity and specificity in detecting early caries.

Inspection of aerospace components has always been a challenge. Lock-in thermography is an active technique which is popularly being used for the nondestructive evaluation of subsurface defects in composite materials such as carbon-fiber-reinforced-polymer (CFRP) in aircraft structures. CFRP-foam layered structure composite is often used for anti-heat and adiabatic material in aerospace components. In this paper, a finite element analysis (FEA) of 3D heat conduction is developed in order to investigate the behavior of thermal waves in the CFRP-foam layered structure plates with finite thickness under convective and radiate conditions. The FEA simulation is then utilized to predict the magnitude and phase differences produced by CFRP face-sheet subsurface defects to obtain the optimum inspection parameters. The simulation results are compared with the experimental data. The use of optimum inspection parameters of lock-in thermography to detect PVC modeling defects of CFRP-foam layered structure is also presented in this paper.

A space monocrystalline silicon (c-Si) solar cell under low-energy (< 1 MeV) electron irradiation was investigated using noncontact photocarrier radiometry (PCR). Monte Carlo simulation (MCS) was employed to characterize the effect of different energy electron irradiation on the c-Si solar cell. The carrier transport parameters (carrier lifetime, diffusion coefficient, and surface recombination velocities) were obtained by best fitting the experimental results with a theoretical one-dimensional two-layer PCR model. The results showed that the increase of the irradiation electron energy caused a large reduction of the carrier lifetime and diffusion length. Furthermore, the rear surface recombination velocity of the Si:p base of the solar cell at the irradiation electron energy of 1 MeV was dramatically enhanced due to 1 MeV electron passing through the whole cell. Short-circuit current (Isc) degradation evaluated by PCR was in good agreement with that obtained by electrical measurement.

In this paper, the modulated laser-induced excess minority carrier density wave (CDW) of bipolar semiconductor is developed. An analytical expression of CDW in frequency domain is introduced. The numerical simulations are carried out to analyze the effects of minority carrier transport parameters (minority carrier lifetime, diffusion coefficient, and two surfaces recombination velocities) on response of laser-induced photocarrier radiometry (PCR) signal to frequency for semiconductor silicon wafer. The PCR amplitude increases with increasing the minority carrier lifetime, and decreased with increasing the carrier diffusion coefficient and surface recombination velocity. In contrast, the PCR phase lag decreases with increasing the minority carrier lifetime, and increases with increasing the carrier diffusion coefficient and surface recombination velocity. The silicon (Si) wafer with an artificial defect (mechanical scratch) on the surface is experimentally investigated by PCR scanning image system. The distribution maps of the minority carrier transport parameters are obtained by best-fitting method which is based on the carrier density wave analytical expression, and the influences of the artificial defect on carrier transport parameters are discussed in detail. The experimental results indicate that the surface recombination velocity and carrier diffusivity at artificial damaged location are dramatically increased compared with those in the healthy region. The carrier bulk lifetime of whole Si wafer is obtained to be about 38.33 μs by PCR scanning image measurements. Simultaneously, quasi steady-state photoconductance (QSSPC) method is used to measure the carrier effective lifetime of Si wafer, and it is about 33.85 μs. Therefore, the carrier bulk lifetime of Si wafer by PCR scanning image measurement is in good agreement with the QSSPC measurement. However, QSSPC measurement could obtain only the carrier effective lifetime of Si wafer. Furthermore, PCR scanning image measurement can be employed to measure the carrier transport parameters with high resolution in comparison with QSSPC measurement, and to evaluate the localized imperfection.

The photon-density wave is generated in tooth tissue due to the scattering induced by modulated laser beams, and furthermore, thermal-wave will form because of photothermal effect. A one-dimensional thermal-wave model for three-layer tooth tissue using modulated laser stimulation is developed based on 1D diffusion approximation of the radiative transfer theory in combination with 1D heat conduction equation. Effects of photothermal properties (i.e. light absorption coefficient, scattering coefficient and thermal diffusivity coefficient), enamel depth and caries depth on the photothermal radiometry (PTR) dynamic responses are investigated based on the 1D thermal wave model coupling with photon-density wave. The PTR amplitude and phase delay (the phase difference between the PTR signal and reference signal) are strongly dependent on the photothermal parameters of the dental enamel caries layers (DECLs). PTR amplitude and phase delay increase with increasing DECL absorption coefficient, scattering coefficient and thermal diffusivity. Additionally, PTR amplitude may also increase due to the larger thickness of caries layer, and the PTR phase peak value is generated at low frequencies. The inhomogeneous photothermal properties of dental enamel healthy layer (DEHL) also have obviously influenced PTR amplitude and phase. Increasing DEHL scattering coefficient leads to the increase of PTR amplitude, but has no apparent effect on the PTR phase. While the PTR phase delay increases with increasing DEHL absorption coefficient. The delay of PTR amplitude and phase is enlarged at the high value of DEHL thermal diffusivity. However, the DEHL layer thickness has no apparent effect on the PTR amplitude and phase.The PTR signal of tooth tissue induced by the 808 nm diode laser is monitored using an infrared detector (HgCdTe, spectral width 2.012.0 m), and the PTR amplitude and phase response are obtained using lock-in amplifier (SR830). Through frequency-scanning experiments of dental tissue, PTR dynamic responses can be measured and employed to characterize the inhomogeneity and caries of the tooth tissue. The photothermal parameters and caries characteristic of the tooth issue can be simultaneously obtained by multi-parameters statistic best-fit.Simulation and experimental results show that the PTR dynamic response has the advantages of high sensitivity and high contrast for inhomogeneity and caries of the tooth tissue.

We have demonstrated that Valpha24(+)Vbeta11(+) invariant (Valpha24(+)i) NKT cells from patients with allergic asthma express CCR9 at high frequency. CCR9 ligand CCL25 induces chemotaxis of asthmatic Valpha24(+)i NKT cells but not the normal cells. A large number of CCR9-positive Valpha24(+)i NKT cells are found in asthmatic bronchi mucosa, where high levels of Th2 cytokines are detected. Asthmatic Valpha24(+)i NKT cells, themselves Th1 biased, induce CD3(+) T cells into an expression of Th2 cytokines (IL-4 and IL-13) in cell-cell contact manner in vitro. CD226 are overexpressed on asthmatic Valpha24(+)i NKT cells. CCL25/CCR9 ligation causes directly phosphorylation of CD226, indicating that CCL25/CCR9 signals can cross-talk with CD226 signals to activate Valpha24(+)i NKT cells. Prestimulation with immobilized CD226 mAb does not change ability of asthmatic Valpha24(+)i NKT cells to induce Th2-cytokine production, whereas soluble CD226 mAb or short hairpin RNA of CD226 inhibits Valpha24(+)i NKT cells to induce Th2-cytokine production by CD3(+) T cells, indicating that CD226 engagement is necessary for Valpha24(+)i NKT cells to induce Th2 bias of CD3(+) T cells. Our results are providing with direct evidence that aberration of CCR9 expression on asthmatic Valpha24(+)i NKT cells. CCL25 is first time shown promoting the recruitment of CCR9-expressing Valpha24(+)i NKT cells into the lung to promote other T cells to produce Th2 cytokines to establish and develop allergic asthma. Our findings provide evidence that abnormal asthmatic Valpha24(+)i NKT cells induce systemically and locally a Th2 bias in T cells that is at least partially critical for the pathogenesis of allergic asthma.

Humans and mice with systemic lupus erythematosus (SLE) and related autoimmune diseases have reduced numbers of NK T cells. An association between NK T cell deficiency and autoimmune disease has been identified. However, the mechanisms for reduction of NK T cell number in patients with SLE are unknown. In the present study we report that NK T cells from active SLE patients are highly sensitive to anti-CD95-induced apoptosis compared with those from normal subjects and inactive SLE patients. CD226 expression is deficient on NK T cells from active SLE patients. The expression of one antiapoptotic member protein, survivin, is found to be selectively deficient in freshly isolated NK T cells from active SLE patients. CD226 preactivation significantly up-regulates survivin expression and activation, which can rescue active SLE NK T cells from anti-CD95-induced apoptosis. In transfected COS7 cells, we confirm that anti-CD95-mediated death signals are inhibited by activation of the CD226 pathway through stabilization of caspase-8 and caspase-3 and through activation of survivin. We therefore conclude that deficient expression of CD226 and survivin in NK T cells from active SLE is a molecular base of high sensitivity of the cells to anti-CD95-induced apoptosis. These observations offer a potential explanation for high apoptotic sensitivity of NK T cells from active SLE, and provide a new insight into the mechanism of reduction of NK T cell number in SLE and understanding the association between NK T cell deficiency and autoimmune diseases.

In a total of 38 typical T-cell lineage acute lymphocytic leukemia (T-ALL) and T-cell lineage chronic lymphocytic leukemia (T-CLL) cases investigated, we found that CC chemokine receptor CCR9 was selectively and frequently expressed on T-ALL CD4+ T cells, was moderately expressed on T-CLL CD4+ T cells, and was rarely expressed on normal CD4+ T cells. These findings were demonstrated at protein and mRNA levels using flow cytometry and real-time quantitative reverse transcription-PCR technique and were verified by digital confocal microscopy and Northern blotting. Thymus-expressed chemokine, a ligand for CCR9, selectively induced T-ALL CD4+ T-cell chemotaxis and adhesion. Interleukin (IL)-2 and IL-4, together, down-regulated the expression and functions of CCR9 in T-ALL CD4+ T cells including chemotaxis and adhesion. It was also demonstrated that IL-2 and IL-4, together, internalized CCR9 on T-ALL CD4+ T cells and subsequently inhibited functions of CCR9 in these cells. Thymus-expressed chemokine mRNA was highly expressed in CD4+ T cells, involving lymph node and skin in T-ALL patients, and was expressed at moderate levels in lymph node and skin tissues in T-CLL patients. Our findings may provide new clues to understanding various aspects of T-ALL CD4+ T cells, such as functional expression of CCR9-thymus-expressed chemokine receptor-ligand pairs as well as the effects of IL-2 and IL-4, which may be especially important in cytokine/chemokine environment for the pathophysiological events of T-ALL CD4+ T-cell trafficking.

An analytic mathematical model of modulated laser-induced minority carrier density wave of silicon solar cells is developed, and light-induced carrier recombination radiation luminescence method (photocarrier radiometry (PCR)) is employed to detect the doping concentration, impedance and carrier transport parameters. The double knee characteristics of frequency domain response curve are investigated, and in a small ac signal case, the equivalent circuit topology structure of a solar cell is constructed. Through simulation analysis based on minority carrier density wave mathematical model, the effects of doping concentration, resistance and carrier transport parameters on the PCR frequency domain response are investigated. Donor/acceptor concentration, shunt resistance and carrier transport parameters of Si solar cell are obtained by PCR frequency-scanning experiments and multi-parameter fitting. The results show that the first knee position of PCR-detected large-area solar-cell frequency domain response curve is determined by the capacitive effect. The simplified mathematical model can be used to quantitatively describe and determine the doping concentration, shunt resistance and carrier transport parameters of silicon solar cell.

We have demonstrated that Vα24+Vβ11+ invariant (Vα24+i) NKT cells from patients with allergic asthma express CCR9 at high frequency. CCR9 ligand CCL25 induces chemotaxis of asthmatic Vα24+i NKT cells but not the normal cells. A large number of CCR9-positive Vα24+i NKT cells are found in asthmatic bronchi mucosa, where high levels of Th2 cytokines are detected. Asthmatic Vα24+i NKT cells, themselves Th1 biased, induce CD3+ T cells into an expression of Th2 cytokines (IL-4 and IL-13) in cell-cell contact manner in vitro. CD226 are overexpressed on asthmatic Vα24+i NKT cells. CCL25/CCR9 ligation causes directly phosphorylation of CD226, indicating that CCL25/CCR9 signals can cross-talk with CD226 signals to activate Vα24+i NKT cells. Prestimulation with immobilized CD226 mAb does not change ability of asthmatic Vα24+i NKT cells to induce Th2-cytokine production, whereas soluble CD226 mAb or short hairpin RNA of CD226 inhibits Vα24+i NKT cells to induce Th2-cytokine production by CD3+ T cells, indicating that CD226 engagement is necessary for Vα24+i NKT cells to induce Th2 bias of CD3+ T cells. Our results are providing with direct evidence that aberration of CCR9 expression on asthmatic Vα24+i NKT cells. CCL25 is first time shown promoting the recruitment of CCR9-expressing Vα24+i NKT cells into the lung to promote other T cells to produce Th2 cytokines to establish and develop allergic asthma. Our findings provide evidence that abnormal asthmatic Vα24+i NKT cells induce systemically and locally a Th2 bias in T cells that is at least partially critical for the pathogenesis of allergic asthma.

Selectively frequent expression of CXCR5 enhances resistance to apoptosis in CD8 + CD34 + T cells from patients with T-cell-lineage acute lymphocytic leukemia