When a leakage event occurs, the values of pressure sensors in the water distribution network will drop, and leakage alarms will be triggered if the drop in pressure values exceed the alarm ...thresholds. Due to the similarity of the leakage characteristics between the adjacent nodes, it is difficult to identify the exact leakage node. Therefore, in this paper, a leakage zone identification method based on alarm levels and pattern identification is proposed. At first, leakage residual samples for each node are generated within the range of the leakage amount. To reduce the influence of nodes with similar leakage residual characteristics on the identification results, the residual values of each sample are converted into alarm levels. For the training samples, nodes with the same alarm level sample are merged into a node group and used as a label. Then, the Euclidean distance method is used to test the identification effect of the model. The enumeration method is adopted to optimize the sample interval, the alarm level interval and the feature dimension to enable the model to achieve an appropriate identification result. A life-sized network is presented in this paper to demonstrate the effectiveness of the proposed method. The results show that compared with the previous leakage zone identification method based on alarm characteristics, the proposed method can effectively reduce the size of the candidate leakage zone.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The postnatal thymus is the primary source of T cells in vertebrates, and many if not all stages of thymocyte development require interactions with thymic epithelial cells (TECs). The Foxn1 gene is a ...key regulator of TEC differentiation, and is required for multiple aspects of fetal TEC differentiation. Foxn1 is also expressed in the postnatal thymus, but its function after birth is unknown. We generated a Foxn1 allele with normal fetal expression and thymus development, but decreased expression in the postnatal thymus. This down-regulation causes rapid thymic compartment degeneration and reduced T-cell production. TEC subsets that express higher Foxn1 levels are most sensitive to its down-regulation, in particular MHCIIhiUEA-1hi medullary TECs. The requirement for Foxn1 is extremely dosage sensitive, with small changes in Foxn1 levels having large effects on thymus phenotypes. Our results provide the first evidence that Foxn1 is required to maintain the postnatal thymus. Furthermore, the similarities of this phenotype to accelerated aging-related thymic involution support the possibility that changes in Foxn1 expression in TECs during aging contribute to the mechanism of involution.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The impact of floods can be devastating to buildings, especially in countries and villages in mountainous areas. Based on the flood impact risk analysis results, two methods are suggested by authors ...to improve the flood impact defense capability of rural buildings in this paper: increasing the strength of the mortar used in masonry structures, as well as adding reinforced concrete (RC) columns and circle beams to masonry structures. The impact of floods on the reinforced masonry structures is simulated numerically, and the failure process, stress, and deformation behaviors of masonry structures are analyzed. Compared to the computational results of normal masonry structures, the advantages of the two methods proposed in this manuscript are studied. Increasing the mortar strength slows the rate of damage to the masonry structure but does not improve the deformation or the failure behaviors. Increasing the mortar strength slightly decreases the first principal stress on the mortar and brick elements but has no effect on the third principal stress. Adding the RC frames not only delays the damage to the building and improves the failure behavior of the masonry structure but also decreases the first and third principle stresses of the brick and mortar elements.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Total body irradiation (TBI) damages hematopoietic cells in the bone marrow and thymus; however, the long-term effects of irradiation with aging remain unclear. In this study, we found that the ...impact of radiation on thymopoiesis in mice varied by sex and dose but, overall, thymopoiesis remained suppressed for ≥12 mo after a single exposure. Male and female mice showed a long-term dose-dependent reduction in thymic cKit
lymphoid progenitors that was maintained throughout life. Damage to hematopoietic stem cells (HSCs) in the bone marrow was dose dependent, with as little as 0.5 Gy causing a significant long-term reduction. In addition, the potential for T lineage commitment was radiation sensitive with aging. Overall, the impact of irradiation on the hematopoietic lineage was more severe in females. In contrast, the rate of decline in thymic epithelial cell numbers with age was radiation-sensitive only in males, and other characteristics including
transcription were unaffected. Taken together, these data suggest that long-term suppression of thymopoiesis after sublethal irradiation was primarily due to fewer progenitors in the BM combined with reduced potential for T lineage commitment. A single irradiation dose also caused synchronization of thymopoiesis, with a periodic thymocyte differentiation profile persisting for at least 12 mo postirradiation. This study suggests that the number and capability of HSCs for T cell production can be dramatically and permanently damaged after a single relatively low TBI dose, accelerating aging-associated thymic involution. Our findings may impact evaluation and therapeutic intervention of human TBI events.
Thymic epithelial cells (TECs) are essential for T cell development in the thymus, yet the mechanisms governing their differentiation are not well understood. Lin28, known for its roles in embryonic ...development, stem cell pluripotency, and regulating cell proliferation and differentiation, is expressed in endodermal epithelial cells during embryogenesis and persists in adult epithelia, implying postnatal functions. However, the detailed expression and function of Lin28 in TECs remain unknown. In this study, we examined the expression patterns of
and its target
in fetal and postnatal TECs and discovered opposing expression patterns during postnatal thymic growth, which correlated with FOXN1 and MHCII expression. Specifically,
showed high expression in MHCII
TECs, whereas
was expressed in MHCII
TECs. Deletion of
and
specifically in TECs resulted in reduced MHCII expression and overall TEC numbers. Conversely, overexpression of
increased total TEC and thymocyte numbers by promoting the proliferation of MHCII
TECs. Additionally, our data strongly suggest that
and
expression is reliant on FOXN1 to some extent. These findings suggest a critical role for Lin28 in regulating the development and differentiation of TECs by modulating MHCII expression and TEC proliferation throughout thymic ontogeny and involution. Our study provides insights into the mechanisms underlying TEC differentiation and highlights the significance of Lin28 in orchestrating these processes.
The postnatal thymus is an efficient microenvironment for T cell specification and differentiation. B cells are also present in the thymus and have been recently shown to impact T cell selection, ...however, the mechanisms controlling B cell development in the thymus are largely unknown. In Foxn1lacZ mutant mice, down-regulation of Foxn1 expression in thymic epithelial cells beginning 1 week after birth caused a dramatic reduction of T progenitors and an increase of B cell progenitors. This time point is coincident with the switch from fetal to adult-type hematopoietic stem cells (HSCs), which is regulated by the Lin28-Let7 system. We hypothesize that the thymic environment might regulate this process to suppress fetal-type B cell development in the thymus. In this study we show that in the Foxn1lacZ thymus, although the down-regulation of Lin28 in thymocytes was normal, up-regulation of Let-7 was impaired. The failure to up-regulate Let-7 caused a transient increase of Arid3a in B precursors, which is known to promote fetal-type B cell fate. Over-expression of Lin28a in HSCs also reduced Let-7 and promoted Arid3a expression in BM and thymic B progenitors, increasing B cell production in the thymus. The level of Let-7 in thymic B progenitors was up regulated by in vitro co-culture with IL15, Vitamin-D3, and retinoic acid, thus down-regulating Arid3a to promote B cell differentiation. All of these signals were produced in thymic epithelial cells (TECs) related to Let-7 expression in thymic B progenitors, and down-regulated in Foxn1lacZ mutants. Our data show that signals provided by TEC control thymic B cell development by up-regulating Let-7, suppressing Arid3a expression in intrathymic progenitor B cells to limit their proliferation during the neonatal to adult transition.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The safe use of hydrogen energy is expected to solve the dual problems of the environment and energy in the future. However, because of the flammable and explosive characteristics of hydrogen, new ...sensing technologies that can reliably monitor the concentration of hydrogen are urgently needed. Fiber optic sensing technology has the advantages of good electrical insulation performance, strong anti-electromagnetic interference ability, non-invasive, high sensitivity, easy to realize the long-distance monitoring of the measured signal, corrosion resistance, explosion-proof, flexible optical path, easy to connect with the computer and so on. Based on the above advantages, this paper uses the hydrogen-induced discoloration effect of WO
3
-Pd
2
Pt-Pt nanocomposite films to construct a fiber-optic hydrogen sensing system based on dual photodetectors, which is closely integrated with Internet technology. It can realize the real-time monitoring of hydrogen concentration in life and production and is of great significance to the safe operation of national defense security and national economic construction.
Hematopoietic stem cells (HSCs) derived from birth through adult possess differing differentiation potential for T or B cell fate in the thymus; neonatal bone marrow (BM) cells also have a higher ...potential for B cell production in BM compared to adult HSCs. We hypothesized that this hematopoietic-intrinsic B potential might also regulate B cell development in the thymus during ontogeny.
Foxn1lacZ mutant mice are a model in which down regulation of a thymic epithelial cell (TEC) specific transcription factor beginning one week postnatal causes a dramatic reduction of thymocytes production. In this study, we found that while T cells were decreased, the frequency of thymic B cells was greatly increased in these mutants in the perinatal period. We used this model to characterize the mechanisms in the thymus controlling B cell development.
Foxn1lacZ mutants, T cell committed intrathymic progenitors (DN1a,b) were progressively reduced beginning one week after birth, while thymic B cells peaked at 3-4 weeks with pre-B-II progenitor phenotype, and originated in the thymus. Heterochronic chimeras showed that the capacity for thymic B cell production was due to a combination of higher B potential of neonatal HSCs, combined with a thymic microenvironment deficiency including reduction of DL4 and increase of IL-7 that promoted B cell fate.
Our findings indicate that the capacity and time course for thymic B-cell production are primarily controlled by the hematopoietic-intrinsic potential for B cells themselves during ontogeny, but that signals from TECs microenvironment also influence the frequency and differentiation potential of B cell development in the thymus.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Efficient and high-volume-fraction packing conducted by motion simulation strategy.•Support mapping applied to representation and collision detection of aggregates.•The packing time varied ...logarithmically with the aggregate content.
Numerical simulation using a mesoscale model is an effective method to determine the complex mechanical behaviors of concrete. Establishing a numerical sample with a mesostructure close to realistic concrete is crucial for mesoscale simulation. This paper presents a heuristic packing algorithm for constructing 3D random aggregate models with high aggregate content. In the algorithm, the aggregate packing problem is considered as a problem of optimizing the potential energy of the mesoscale configuration. In the initial state, all aggregate particles are randomly placed inside the specimen container; then, the particles move in the container according to the proposed motion simulation strategy until a feasible spatial configuration is obtained. The framework is suitable for various types of aggregates, including spherical, ellipsoidal, polyhedral, and mixed-type aggregates, that have a support mapping representation. In this study, numerous samples with different types of aggregates were established, and the influence of the aggregate gradation on the packing density was examined. The results verified the efficiency and robustness of the proposed algorithm.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Method for meshing of concrete RVEs with real ITZ thickness.•Numerical prediction of elastic modulus of concrete using a 3D three-phase model.•Models were verified with theoretical, numerical, and ...experimental results.•Results of 3D models with random configurations exhibit negligible dispersion.•3D numerical models offer a more accurate and reliable prediction than 2D models.
In this study, the elastic modulus of a concrete material was predicted using three-dimensional (3D) numerical models based on asymptotic homogenization. A novel meshing method was developed to discretize the mesoscale model of concrete with an arbitrary thickness of the interfacial transition zone (ITZ), offering a low computational cost with accurate ITZ representation. A practical implementation of asymptotic homogenization using ABAQUS was presented. Numerical models were verified by comparison with theoretical predictions, published numerical results, and experimental data. The results prove that the proposed numerical model is adequate to offer an accurate estimate of the elastic modulus of concrete. A systematic parametric study was conducted to investigate the effects of the mesostructural characteristics on the elastic modulus of concrete. The results indicate that the aggregate shape has a slight influence on the elastic modulus of concrete. The effect of the ITZ thickness is small owing to its much lower volume fraction compared with that of the aggregate and mortar. Moreover, the elastic moduli of concrete predicted by the 3D numerical models using random configurations exhibit negligible dispersion. A significant difference between the 3D and 2D numerical results demonstrates that 3D numerical models offer a more accurate and reliable prediction of the elastic modulus of concrete.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
PDF
