Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 33

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
In order to enhance the authenticity and accuracy simulation of passengers’ evacuation in ships, a new multi-grid model is proposed on the basis of cellular automata theory. By finer lattice the multi-grid model could enhance the continuity of passengers’ track and the precision of boundary’s qualification compared with traditional cellular automata model. Attraction, repulsion and friction are also quantized in the multi-grid model to present the impact of interaction force among pedestrians. Furthermore, crowd’s evacuation simulated by traditional cellular automata and multi-grid model in single exit room and typical cabin environment have been taken as examples to analyze crowd’s motion laws. It is found that the laws of passengers’ evacuation simulated by the two models are similar, and the simulation authenticity and accuracy is enhanced by the multi-grid model
Suaeda salsa calli treated with different concentrations of NaCl were used to examine the response of the plasma membrane (PM) H⁺-ATPase to NaCl and its role in salt tolerance. The optimum concentration of NaCl for growth of the calli was 50 mM, while growth was significantly inhibited at 250 mM NaCl. The ion and organic solute contents of calli increased with increasing NaCl. Activity of the PM H⁺-ATPase increased when the calli were treated with NaCl over a certain concentration range (0–150 mM NaCl). However, the activity reached its maximum with 150 mM NaCl. Immunoblotting analysis of the PM H⁺-ATPase protein from calli cultures with anti- Zea mays H⁺-ATPase serum (monoclonal 46E5B11D5) identified a single polypeptide of ~90 kDa. The peptide levels increased in the calli treated with NaCl at 150 mM NaCl compared to control, but the increase at 50 mM NaCl was less pronounced. Northern blot analysis showed that the expression of the PM H⁺-ATPase also increased after the calli were treated with NaCl. These results suggest that the increase in PM H⁺-ATPase activity is due to both an increase in the amount of PM H⁺-ATPase protein and an up-regulation of the PM H⁺-ATPase gene, which is involved in the salt tolerance of S. salsa calli.
Adjuvant chemotherapy has become the frequently adopted standard therapeutic approach for non-small cell lung cancer (NSCLC). However, the development of multidrug resistance (MDR) is a major obstacle contributing to the failure of chemotherapy. This study aimed to identify genes associated with MDR development that predict tumor response to chemotherapy in NSCLC. In the present study, a multidrug-resistant NSCLC cell sub-line, A549/MDR, was established from the A549/DDP cell line and characterized. The resistance index (RI) of this subline was calculated according to the IC50 of A549/MDR relative to the parental A549/DDP cells. The gene expression profiles of A549/DDP and A549/MDR were obtained using an oligonucleotide microarray (Agilent SureHyb microarray chip). The microarray results were validated by qRT-PCR and selected genes were analyzed by in vitro loss-of-function experiments. Gene expression profiling identified 921 differentially expressed genes (DEGs) according to the selection criteria, in which 541 genes were upregulated and 380 genes were downregulated in A549/MDR compared with A549/DDP cells. We found that these DEGs are involved in diverse biological processes, including ribonucleoprotein complex, drug metabolism, the Hippo signaling pathway and transcriptional misregulation. NOLC1, as one of the identified DEGs, was confirmed to be overexpressed in A549/MDR cells and its knockdown significantly enhanced the drug sensitivity of A549/MDR cells in response to multidrug treatment. Furthermore, knockdown of NOLC1 downregulated the expression levels of drug resistance-associated molecules (LRP and MDR1) in A549/MDR cells. These findings provide a new and comprehensive expression profile of MDR in NSCLC cells. Identification and validation of NOLC1 might be a promising therapeutic strategy for the management of MDR of NSCLC patients.
Coastline is one type of valuable non-renewable resources. From the perspective of economic theory, it can gather population, promote traffic construction, and then improve the level of international trade. The research object of this paper is the coastline resource in Dafeng area. Firstly, we have a brief summary of the existing coastline evaluation literature, then introduce the location and natural attributes of the coastline resources in Dafeng. Following that, the Analytic Hierarchy Process (AHP) model is used to build the economic evaluation index system based on the characteristics of coastline in Dafeng. Specially, this index system consists of 6 factors, and a total of 41 detailed indicators were chosen including water depth, GDP, etc. On this basis, we use the assignment method to quantify the weight of each index, and calculate the comprehensive score of coastline resource by using the YAAHP software. The final conclusion is as follows: The total score of economic evaluation of coastline resource in Dafeng is 0.87. Therefore, the coastline resource in Dafeng will eventually be constructed a unique coastal economic zone, where the implemented port industrial projects will include shipbuilding, logistics, mechanical processing etc
In order to increase the recoveries of steroid estrogens (SEs) for quantitative determination in sewage, response surface methodology (RSM) was adopted to optimize the solid-phase extraction (SPE) procedure. Quadratic models were established for predicting SE recoveries, and the effectiveness of models and the interaction of factors were analyzed. SE concentrations of typical sewage treatment plants (STPs) in Jiangsu province were detected under the optimized conditions. The optimal operating conditions of SPE were obtained with elution volume of 10.68 mL, a sample rate of 10.47 mL·min-1 and elution rate of 4.07 mL·min-1. The predicted recoveries were 81.63% for E1, 88.86% for E2, and 84.55% for EE2. SEs were detected in all the three STPs, and concentrations in the influents and effluents ranged from 13.4 to 78.0 ng·L-1 and from 5.3 to 20.5 ng·L-1, respectively.
Root border cells (RBC) are cells surrounding the root apex. They are functionally different from the apex and are considered to play a role in the protection of the root tip from biotic and abiotic stresses. We investigated RBC viability, formation, and pectin methylesterase (PME) activity of the root caps during RBC development in cowpea (Vigna ungniculata ssp. sesquipedalis) under aeroponic culture. The results showed that the border cells formed almost synchronously with the emergence of the root tip. The number of border cells reached the maximum when roots were approximately 15 mm long. Pectin methylesterase (PME) activity of the root cap peaked at a root length of 1 mm. Root border cells separated from the root cap died within 24 h under Al³⁺ stress while those still attached to the root cap maintained 85% viability at 48 h after treatment. The PME activity did not differ significantly under different Al³⁺ treatments.
The objective of this study was to test whether haem oxygenase-1 (HO-1) is involved in hydrogen peroxide (H₂O₂)-induced lateral root (LR) formation. The results showed that 0.1 mM H₂O₂ mimicked the effects of the HO-1 inducer, haemin, on the up-regulation of tomato HO-1 (SlHO1) expression, increased carbon monoxide (CO) synthesis and LR formation. However, 1.0 mM H₂O₂ resulted in inhibitory responses. The above inducible or inhibitory responses elicited by 0.1 and 1.0 mM H₂O₂ were noticeably blocked or rescued by the HO-1 inhibitor zinc protoporphyrin IX (ZnPP) or haemin, and then separately reversed by CO or ZnPP. Further trials showed that haemin-induced responses were not altered by the H₂O₂ trap, dimethylthiourea (DMTU). When applied alone, DMTU not only decreased H₂O₂ contents but also inhibited SlHO1 expression and LR development. These responses were recovered by the application of haemin or CO. Molecular evidence revealed that H₂O₂-modulated expression of the target genes responsible for LR formation was blocked by ZnPP, but rescued by CO. Salinity-induced up-regulation of HO-1 expression and thereafter LR formation were also dependent on the H₂O₂ generation. Overall, these results demonstrated a possible role of HO-1 in the H₂O₂-induced tomato LR formation.
The micro air nucleus widely distributed in the ocean is a necessary condition for the cavitation of hydraulic machinery in seawater. In order to study the stability of air nucleus in seawater and cavitation inception, the computational domain of water molecules with air nucleus was studied using the method of molecular dynamics simulation, and the transient characteristics of air nucleus in liquid water were obtained. The key factors influencing nuclei stability were analyzed. The results showed that air nucleus with a certain mass could maintain the dynamic equilibrium in liquid water. The internal density of air nuclei had a critical value that allowed the nuclei to stably exist in water. The air nuclei mass was the decisive factor in its equilibrium volume in water, and the two were positively correlated. The internal density of air nuclei was negatively correlated with the nuclei radius when the nuclei was stable in water. Liquid surface tension was an important factor affecting the stability of the air nuclei. The larger the initial radius of nuclei, the smaller the water pressure, and the more likely the cavitation occurs
Excess salts in soil severely inhibit plant growth and yield. Various nutrients can relieve the inhibitory effect of salt on plants. Elaeagnus angustifolia is a tree species that is utilized in landscaping and ecological restoration in China and shows tolerance to saline soils. In this experiment, we first determined the optimal concentration of single-nutrient inputs for promoting growth of E. angustifolia seedlings and alleviating salt stress. The optimal nitrogen (NO₃⁻), phosphorus (PO₄³ ⁻), potassium (K⁺ ), and calcium (Ca²⁺ ) concentrations under salt stress were 2, 0.6, 2, and 2 mM, respectively. Based on this result, we carried out an optimum nutrient ratio experiment by a four-factor and three-level orthogonal experiment. The results showed that under normal growth conditions, the optimal nutrient combinations for NO₃⁻, PO₄³ ⁻, K⁺ , and Ca²⁺ were 2, 0.6, 5, and 1 mM; 5, 0.2, 5, and 2 mM; and 5, 0.6, 1, and 5 mM, respectively, which increased plant height, biomass, and the chlorophyll content of E. angustifolia seedlings. Under salt stress, the optimal nutrient combinations were 5, 0.2, 5, and 2 mM; and 5, 0.6, 1, and 5 mM, respectively. This study provides a theoretical basis for optimal fertilization of E. angustifolia seedlings in saline-alkali soils.
Thellungiella halophila is a salt tolerant relative of Arabidopsis thaliana with high genetic and morphological similarity. In the present study, effects of salinity on germination and seedling growth of T. halophila and A. thaliana were compared. The present results showed that the salinity inhibited seed germination in both species. Unexpectedly, percentages of seed germination in A. thaliana were higher than T. halophila in a range of 0–200 mM NaCl. Seeds of both species could not germinate when the concentration of NaCl was over 200 mM. However, when compared with A. thaliana, seeds of T. halophila did not suffer ion toxicity, as evidenced by the higher final germination rate after ungerminated seeds pretreated with NaCl were transferred to distilled water. Seedlings of T. halophila were more salt tolerant than those of A. thaliana, e.g., seedlings of T. halophila had better plant growth (root length, fresh and dry mass), higher chlorophyll content, less MDA content and higher proline content and K⁺/Na⁺ ratio under salinity. These results indicate that T. halophila is more salt tolerant than A. thaliana during both seed germination and seedling stages and explain why A. thaliana is excluded from saline locations and T. halophila can survive in saline soils.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.