Analysis on the Tendon Spacing of Prestressed Tunnel Liner

In this paper, based on cylindrical shell theory of elastic mechanics, the mechanical property of prestressed concrete lining structure was studied; models of calculating infinitely-long structure and semi-infinitely-long structure were established; theoretical formulas of normal displacement and inner force on the middle surface were deduced; the maximum influence scope of stress was determined and the superposition formula of maximum cable spacing was deduced. Combing observed data in practical project, the theoretical result and measured result of circumferential stress in prestressed concrete lining structure was compared. Results reveal that the theoretical result coincides with the measured value and that the method determining maximum cable spacing can be applied into practical projects. The even distribution of circumferential stress in the axial direction caused by the tensile force of anchor cable is not a factor determining the cable spacing

Coupling CO₂-to-Ethylene Reduction with the Chlor-Alkaline Process in Seawater through In Situ-Formed Cu Catalysts

The overall commercial value of a CO2 electroreduction system is hindered by the valueless product and high energy consumption of the oxygen evolution reaction (OER) at the anode. Herein, with an in situ-formed copper catalyst, we employed the alternative chlorine evolution reaction for OER, and high-speed formation of both C2 products and hypochlorite in seawater can be realized. The EDTA in the sea salt electrolyte can trigger an intense dissolution and deposition of Cu on the surface of the electrode, resulting in the in situ formation of dendrites of Cu with high chemical activity. In this system, a faradaic efficiency of 47% can be realized for C2H4 production at the cathode and a faradaic efficiency of 85% can be realized for hypochlorite production at the anode with an operation current of 100 mA/cm2. This work presents a system for designing a highly efficient coupling system for the CO2 reduction reaction and alternative anodic reactions toward value-added products in a seawater environment

Exposure of zebrafish embryos/larvae to TDCPP alters concentrations of thyroid hormones and transcriptions of genes involved in the hypothalamic-pituitary-thyroid axis

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) has been frequently detected in the environment and in various biota, including fish, and has been implicated in disruption of the thyroid endocrine system. In the present study, zebrafish (Danio rerio) embryos were exposed to different concentrations of TDCPP (10, 50, 100, 300 and 600 mu g/L) from 2 h post-fertilization (hpf) to 144 hpf. Developmental endpoints, and whole-body concentrations of thyroid hormones and transcriptional profiles of genes involved in the hypothalamic-pituitary-thyroid (HPT) axis were examined. Exposure to TDCPP caused a dose-dependent developmental toxicity, including decreased body weight, reduced hatching, survival and heartbeat rates, and increased malformation (spinal curvature). Treatment with the positive control chemical 3,3',5-triiodo-L-thyronine (T3) significantly decreased whole-body thyroxin (T4) concentrations, increased whole-body T3 concentrations, and upregulated mRNA expression involved in the HPT axis as a compensatory mechanism. These results suggested that the HPT axis in 144-hpf zebrafish larvae was responsive to chemical exposure and could be used to evaluate the effects of chemicals on the thyroid endocrine system. TDCPP exposure significantly decreased whole-body T4 concentrations and increased whole-body T3 concentrations, indicating thyroid endocrine disruption. The upregulation of genes related to thyroid hormone metabolism (dio1 and ugt1ab) might be responsible for decreased T4 concentrations. Treatment with TDCPP also significantly increased transcription of genes involved in thyroid hormone synthesis (tsh beta, slc5a5 and tg) and thyroid development (hhex, nkx2.1 and pax8) as a compensatory mechanism for decreased T4 concentrations. Taken together, these results suggest that TDCPP alters the transcription of genes involved in the HPT axis and changes whole-body concentrations of thyroid hormones in zebrafish embryos/larvae, thus causing an endocrine disruption of the thyroid system. (c) 2012 Elsevier B.V. All rights reserved.Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) has been frequently detected in the environment and in various biota, including fish, and has been implicated in disruption of the thyroid endocrine system. In the present study, zebrafish (Danio rerio) embryos were exposed to different concentrations of TDCPP (10, 50, 100, 300 and 600 mu g/L) from 2 h post-fertilization (hpf) to 144 hpf. Developmental endpoints, and whole-body concentrations of thyroid hormones and transcriptional profiles of genes involved in the hypothalamic-pituitary-thyroid (HPT) axis were examined. Exposure to TDCPP caused a dose-dependent developmental toxicity, including decreased body weight, reduced hatching, survival and heartbeat rates, and increased malformation (spinal curvature). Treatment with the positive control chemical 3,3',5-triiodo-L-thyronine (T3) significantly decreased whole-body thyroxin (T4) concentrations, increased whole-body T3 concentrations, and upregulated mRNA expression involved in the HPT axis as a compensatory mechanism. These results suggested that the HPT axis in 144-hpf zebrafish larvae was responsive to chemical exposure and could be used to evaluate the effects of chemicals on the thyroid endocrine system. TDCPP exposure significantly decreased whole-body T4 concentrations and increased whole-body T3 concentrations, indicating thyroid endocrine disruption. The upregulation of genes related to thyroid hormone metabolism (dio1 and ugt1ab) might be responsible for decreased T4 concentrations. Treatment with TDCPP also significantly increased transcription of genes involved in thyroid hormone synthesis (tsh beta, slc5a5 and tg) and thyroid development (hhex, nkx2.1 and pax8) as a compensatory mechanism for decreased T4 concentrations. Taken together, these results suggest that TDCPP alters the transcription of genes involved in the HPT axis and changes whole-body concentrations of thyroid hormones in zebrafish embryos/larvae, thus causing an endocrine disruption of the thyroid system. (c) 2012 Elsevier B.V. All rights reserved

Effects of tris(1,3-dichloro-2-propyl) phosphate and triphenyl phosphate on receptor-associated mRNA expression in zebrafish embryos/larvae

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and triphenyl phosphate (TPP) are frequently detected in biota, including fish. However, knowledge of the toxicological and molecular effects of these currently used flame retardants is limited. In the present study, an in vivo screening approach was developed to evaluate effects of TDCPP and TPP on developmental endpoints and receptor-associated expression of mRNA in zebrafish embryos/larvae. Exposure to TDCPP or TPP resulted in significantly smaller rates of hatching and survival, in dose- and time-dependent manners. The median lethal concentration (LC50) was 7.0 mg/L for TDCPP and 29.6 mg/L for TPP at 120 hour post-fertilization (hpf). Real-time PCR revealed alterations in expression of mRNAs involved in aryl hydrocarbon receptors (AhRs)-, peroxisome proliferator-activated receptor alpha (PPAR alpha)-, estrogenic receptors (ERs)-, thyroid hormone receptor alpha (TR alpha)-, glucocorticoid receptor (GR)-, and mineralocorticoid receptor (MR)-centered gene networks. Exposure to positive control chemicals significantly altered abundances of mRNA in corresponding receptor-centered gene networks, a result that suggests that it is feasible to use zebrafish embryos/larvae to evaluate effects of chemicals on mRNA expression in these gene networks. Exposure to TDCPP altered transcriptional profiles in all six receptor-centered gene networks, thus exerting multiple toxic effects. TPP was easily metabolized and its potency to change expression of mRNA involved in receptor-centered gene networks was weaker than that of TDCPP. The PPAR alpha- and TR alpha-centered gene networks might be the primary pathways affected by TPP. Taken together, these results demonstrated that TDCPP and TPP could alter mRNA expression of genes involved in the six receptor-centered gene networks in zebrafish embryos/larvae, and TDCPP seemed to have higher potency in changing the mRNA expression of these genes. (c) 2012 Elsevier B.V. All rights reserved.Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and triphenyl phosphate (TPP) are frequently detected in biota, including fish. However, knowledge of the toxicological and molecular effects of these currently used flame retardants is limited. In the present study, an in vivo screening approach was developed to evaluate effects of TDCPP and TPP on developmental endpoints and receptor-associated expression of mRNA in zebrafish embryos/larvae. Exposure to TDCPP or TPP resulted in significantly smaller rates of hatching and survival, in dose- and time-dependent manners. The median lethal concentration (LC50) was 7.0 mg/L for TDCPP and 29.6 mg/L for TPP at 120 hour post-fertilization (hpf). Real-time PCR revealed alterations in expression of mRNAs involved in aryl hydrocarbon receptors (AhRs)-, peroxisome proliferator-activated receptor alpha (PPAR alpha)-, estrogenic receptors (ERs)-, thyroid hormone receptor alpha (TR alpha)-, glucocorticoid receptor (GR)-, and mineralocorticoid receptor (MR)-centered gene networks. Exposure to positive control chemicals significantly altered abundances of mRNA in corresponding receptor-centered gene networks, a result that suggests that it is feasible to use zebrafish embryos/larvae to evaluate effects of chemicals on mRNA expression in these gene networks. Exposure to TDCPP altered transcriptional profiles in all six receptor-centered gene networks, thus exerting multiple toxic effects. TPP was easily metabolized and its potency to change expression of mRNA involved in receptor-centered gene networks was weaker than that of TDCPP. The PPAR alpha- and TR alpha-centered gene networks might be the primary pathways affected by TPP. Taken together, these results demonstrated that TDCPP and TPP could alter mRNA expression of genes involved in the six receptor-centered gene networks in zebrafish embryos/larvae, and TDCPP seemed to have higher potency in changing the mRNA expression of these genes. (c) 2012 Elsevier B.V. All rights reserved