首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
姜黄可以有效治疗各种疾病,本研究使用广义规则归纳(GRI)算法分析了《中药方剂大词典》中含姜黄的理血方剂配伍规律。通过利用生物信息学数据挖掘技术和MTT、Elisa和Western blotting实验验证了姜黄关键配方的系统药理机制。发现“姜黄-川芎-当归”配方可以代表姜黄在理血方剂中的关键组方。PPI网络和KEGG途径富集分析表明“姜黄-川芎-当归”能通过调节PI3K/Akt、MAPK、Toll样受体,T细胞受体,EGFR,VEGFR,细胞凋亡,HIF-1等通路(P<0.05),发挥抗炎、改善微循环和抗肿瘤作用。MTT,Elisa法和Western blotting实验表明,“姜黄-川芎-当归”组方能下调p-EGFR、p-PI3K、p-Akt、VEGF和HIF-的表达,抑制人肺癌A549细胞增殖。“姜黄-川芎-当归”组方可能具有多靶点、多途径的药理作用,治疗炎症,微循环障碍,心血管疾病和癌症。总之,本研究找到了一种新的中药配方,为后续研究姜黄的药理机制提供了理论依据和参考。  相似文献   

2.
This study was performed in an Estonian shale-oil mine with the purpose to develop and apply a number of biomarkers for occupational diesel-exhaust exposure monitoring. Increased breathing-zone exposures to exhaust from operators of diesel-powered trucks in the mine was confirmed in the environmental monitoring part of the study, showing a 7.5-fold higher exposure to particle-associated 1-nitropyrene (1-NP) in 50 underground workers compared with 42 surface workers [P.T.J. Scheepers, D. Coggon, L.E. Knudsen, R. Anzion, H. Autrup, S. Bogovski, R.P. Bos, D. Dahmann, P. Farmer, E.A. Martin, V. Micka, V. Muzyka, H.-G. Neumann, J. Poole, A. Schmidt-Ott, F. Seiler, J. Volf, I. Zwirner-Baier, Biomarkers for occupational diesel exhaust exposure monitoring (BIOMODEM)-a study in underground mining, Toxicol. Lett. 134 (2002) 305-317; P.T.J. Scheepers, V. Micka, V. Muzyka, R. Anzion, D. Dahmann, J. Poole, R.P. Bos, Exposure to dust and particle-associated 1-nitropyrene of drivers of diesel-powered equipment in underground mining, Ann. Occp. Hyg. 47 (2003) 379-388]. Analysis of DNA damage by the Comet assay on frozen blood samples was performed on the total study group and showed significantly higher levels (p=0.003) in underground workers (smokers) driving diesel-powered excavation machines (median 155 on a scale from 0 to 400, among 47 persons), compared with surface workers who smoked (median of 90, among 46 persons). The level of DNA damage in underground smokers was significantly higher (p=0.04) than in non-smokers. Samples from 2 of the 3 sampling weeks had significantly lower DNA damage compared with the third week, probably due to timely processing and freezing. These samples also showed significant differences (p<0.001) between underground workers (median 145, among 41 persons) and surface workers (median 60, among 30 persons). An HPLC method was developed for the analysis of (32)P-postlabelled 1-NP-DNA-adducts, and was applied to a sub-sample of 20 workers. No significant differences between surface and underground workers were found in this sub-sample with respect to the minor, unidentified adducts that had similar chromatographic properties to 1-NP adducts, and smoking did not have any effect on adduct levels. No significant effects of the genotypes of GSTM1, GSTP1 and GSTT1 on DNA-adducts and on DNA damage as measured by the Comet assay were found in the total study group. The study confirms an increased level of DNA damage in workers exposed to exhaust from truck-driving in the mine. However, the results of the environmental and biological monitoring of 1-NP did not correlate, suggesting that inhalation exposure to diesel exhaust is not reflected by an increase in 1-NP-DNA-adduct levels and/or that factors other than occupational exposure to diesel exhaust are primary determinants of these DNA-adduct levels.  相似文献   

3.
In the present paper, we investigate the blast induced ground motion recorded at the limestone quarry “Suva Vrela” near Kosjerić, which is located in the western part of Serbia. We examine the recorded signals by means of surrogate data methods and a determinism test, in order to determine whether the recorded ground velocity is stochastic or deterministic in nature. Longitudinal, transversal and the vertical ground motion component are analyzed at three monitoring points that are located at different distances from the blasting source. The analysis reveals that the recordings belong to a class of stationary linear stochastic processes with Gaussian inputs, which could be distorted by a monotonic, instantaneous, time-independent nonlinear function. Low determinism factors obtained with the determinism test further confirm the stochastic nature of the recordings. Guided by the outcome of time series analysis, we propose an improved prediction model for the peak particle velocity based on a neural network. We show that, while conventional predictors fail to provide acceptable prediction accuracy, the neural network model with four main blast parameters as input, namely total charge, maximum charge per delay, distance from the blasting source to the measuring point, and hole depth, delivers significantly more accurate predictions that may be applicable on site. We also perform a sensitivity analysis, which reveals that the distance from the blasting source has the strongest influence on the final value of the peak particle velocity. This is in full agreement with previous observations and theory, thus additionally validating our methodology and main conclusions.  相似文献   

4.
Many studies have been carried out and many commercial software applications have been developed to improve the performances of surface mining operations, especially for the loader-trucks cycle of surface mining. However, there have been quite few studies aiming to improve the mining process of underground mines. In underground mines, mobile mining equipment is mostly scheduled instinctively, without theoretical support for these decisions. Furthermore, in case of unexpected events, it is hard for miners to rapidly find solutions to reschedule and to adapt the changes. This investigation first introduces the motivation, the technical background, and then the objective of the study. A decision support instrument (i.e. schedule optimizer for mobile mining equipment) is proposed and described to address this issue. The method and related algorithms which are used in this instrument are presented and discussed. The proposed method was tested by using a real case of Kittilä mine located in Finland. The result suggests that the proposed method can considerably improve the working efficiency and reduce the working time of the underground mine.  相似文献   

5.
Cancellous bone is a highly porous material, and two types of waves, fast and slow, are observed when ultrasound is used for detecting bone diseases. There are several possible stimuli for bone remodelling processes, including bone fluid flow, streaming potential, and piezoelectricity. Poroelasticity has been widely used for elucidating the bone fluid flow phenomenon, but the combination of poroelasticity with charge density has not been introduced. Theoretically, general poroelasticity with a varying charge density is employed for determining the relationship between wave velocity and attenuation with charge density. Fast wave velocity and attenuation are affected by porosity as well as charge density; however, for a slow wave, both slow wave velocity and attenuation are not as sensitive to the effect of charge density as they are for a fast wave. Thus, employing human femoral data, we conclude that charged ions gather on trabecular struts, and the fast wave, which moves along the trabecular struts, is significantly affected by charge density.  相似文献   

6.
The velocity, attenuation and frequency content of the mechanical pulse wave propagation in gels of various water contents, in normal tissues from various sites and in oedematous tissues from different patients were investigated. The properties of the propagated pulse wave depend on the water content of the gel and the viscoelastic properties of the tissues. From the dependence of the pulse wave propagation velocity on elasticity, viscosity and density, information may be obtained concerning the effects of oedema on the mechanical properties of tissue.  相似文献   

7.
The excavation and production in underground mines are complicated processes which consist of many different operations. The process of underground mining is considerably constrained by the geometry and geology of the mine. The various mining operations are normally performed in series at each working face. The delay of a single operation will lead to a domino effect, thus delay the starting time for the next process and the completion time of the entire process. This paper presents a new approach to the process control for underground mining operations, e.g. drilling, bolting, mucking. This approach can estimate the working time and its probability for each operation more efficiently and objectively by improving the existing PERT (Program Evaluation and Review Technique) and CPM (Critical Path Method). If the delay of the critical operation (which is on a critical path) inevitably affects the productivity of mined ore, the approach can rapidly assign mucking machines new jobs to increase this amount at a maximum level by using a new mucking algorithm under external constraints.  相似文献   

8.
The genotoxic risk of underground coal miners from Turkey   总被引:4,自引:0,他引:4  
A cytogenetic monitoring study was carried out on a group of workers from a bituminous coal mine in Zonguldak province of Turkey, to investigate the genotoxic risk of occupational exposure to coal mine dust. Cytogenetic analysis, namely sister chromatid exchanges (SCEs), chromosomal aberrations (CAs) and micronucleus (MN) tests were performed on a strictly selected group of 39 workers and compared to 34 controls matched for gender, age, and habit. Smoking and age were considered as modulating factors. Both SCE and CA frequencies in coal miners appeared significantly higher than in controls. Similarly, there was a significant increase in the frequency of total micronuclei in exposed group as compared to control group. The effect of smoking on the level of SCE and MN was significant in the control group. A positive correlation between the age and the level of SCE was also found in controls. The frequencies of both SCE and CA were significantly enhanced with the years of exposure. The results of this study demonstrated that occupational exposure to coal mine dust leads to a significant induction of cytogenetic damage in peripheral lymphocytes of workers engaged in underground coal mining.  相似文献   

9.
A cytogenetic monitoring study was carried out on a group of workers from a bituminous coal mine in Zonguldak province of Turkey, to investigate the genotoxic risk of occupational exposure to coal mine dust. Cytogenetic analysis, namely sister chromatid exchanges (SCEs), chromosomal aberrations (CAs) and micronucleus (MN) tests were performed on a strictly selected group of 39 workers and compared to 34 controls matched for gender, age, and habit. Smoking and age were considered as modulating factors. Both SCE and CA frequencies in coal miners appeared significantly higher than in controls. Similarly, there was a significant increase in the frequency of total micronuclei in exposed group as compared to control group. The effect of smoking on the level of SCE and MN was significant in the control group. A positive correlation between the age and the level of SCE was also found in controls. The frequencies of both SCE and CA were significantly enhanced with the years of exposure. The results of this study demonstrated that occupational exposure to coal mine dust leads to a significant induction of cytogenetic damage in peripheral lymphocytes of workers engaged in underground coal mining.  相似文献   

10.
Primary blast injury (PBI) is the general term that refers to injuries resulting from the mere interaction of a blast wave with the body. Although few instances of primary ocular blast injury, without a concomitant secondary blast injury from debris, are documented, some experimental studies demonstrate its occurrence. In order to investigate PBI to the eye, a finite element model of the human eye using simple constitutive models was developed. The material parameters were calibrated by a multi-objective optimisation performed on available eye impact test data. The behaviour of the human eye and the dynamics of mechanisms occurring under PBI loading conditions were modelled. For the generation of the blast waves, different combinations of explosive (trinitrotoluene) mass charge and distance from the eye were analysed. An interpretation of the resulting pressure, based on the propagation and reflection of the waves inside the eye bulb and orbit, is proposed. The peculiar geometry of the bony orbit (similar to a frustum cone) can induce a resonance cavity effect and generate a pressure standing wave potentially hurtful for eye tissues.  相似文献   

11.
We present an association rule mining method for mining high confidence rules, which describe interesting gene relationships from microarray datasets. Microarray datasets typically contain an order of magnitude more genes than experiments, rendering many data mining methods impractical as they are optimised for sparse datasets. A new family of row-enumeration rule mining algorithms have emerged to facilitate mining in dense datasets. These algorithms rely on pruning infrequent relationships to reduce the search space by using the support measure. This major shortcoming results in the pruning of many potentially interesting rules with low support but high confidence. We propose a new row-enumeration rule mining method, MaxConf, to mine high confidence rules from microarray data. MaxConf is a support-free algorithm which directly uses the confidence measure to effectively prune the search space. Experiments on three microarray datasets show that MaxConf outperforms support-based rule mining with respect to scalability and rule extraction. Furthermore, detailed biological analyses demonstrate the effectiveness of our approach -- the rules discovered by MaxConf are substantially more interesting and meaningful compared with support-based methods.  相似文献   

12.
A model for the arterial wall, motivated by wave propagation findings, is developed. The wall is taken to be a viscoelastic, orthotropic, prestressed shell which is materially characterized at any prestress level by ten incremental moduli. By using the momentum equations and the wave propagation characteristics for three axisymmetric modes, the ten moduli are found in terms of the three wave speeds, the three attenuation coefficients and the prestresses.  相似文献   

13.
A review of online biofilm monitoring techniques is presented focusing on methods based on differential turbidimetry, light scattering, heat transfer, pressure drop, real-time measurement of metabolic products, image analysis, radiation signals (spectroscopy, fluorometry, photoacoustic spectroscopy, etc.), electric and mechanical (vibration) signals. The different methods are compared in terms of their applicability to practical situations and the know detection limits are reported.  相似文献   

14.
The model proposed in this paper is based on the fact that the reflection might have a significant contribution to the attenuation of the acoustic waves propagating through the cancellous bone. The numerical implementation of the mentioned effect is realized by the development of a new representative volume element that includes an infinitesimally thin ‘transient’ layer on the contact surface of the bone and the marrow. This layer serves to model the amplitude transformation of the incident wave by the transition through media with different acoustic impedances and to take into account the energy loss due to the reflection. The proposed representative volume element together with the multiscale finite element is used to simulate the wave propagation and to evaluate the attenuation coefficient for samples with different effective densities in the dependence of the applied excitation frequency. The obtained numerical values show a very good agreement with the experimental results. Moreover, the model enables the determination of the upper and the lower bound for the attenuation coefficient.  相似文献   

15.
藏中矿区重金属污染土壤的微生物活性变化   总被引:11,自引:0,他引:11  
微生物几乎参与土壤中的一切生物及生物化学反应,土壤微生物活性可较敏感地反映土壤中生化反应的方向和强度,是探讨重金属污染生态效应的有效途径之一。通过野外调查与采样和室内分析,研究了藏中矿区重金属污染对土壤酶活性、基础呼吸、代谢商(qCO2)和可矿化N的影响。结果表明,矿区土壤受重金属Cu、Zn、Pb、Cd不同程度污染,使得土壤酶活性、可矿化N受到抑制,基础呼吸和qCO2则受到刺激。逐步多元回归分析表明,在Cu、Zn、Pb、Cd复合污染条件下,矿区土壤重金属复合污染对土壤微生物活性的影响是复杂的;主成分分析表明,土壤总体微生物活性指标能较好地反映拉屋矿区土壤重金属复合污染状况,可作为藏中矿区土壤环境质量评价及量化分类的有效指标。  相似文献   

16.
张绍良  米家鑫  侯湖平  杨永均 《生态学报》2018,38(15):5611-5619
最近连续三届世界生态恢复大会都将矿山生态系统列为大会交流的主题之一。为了解矿山生态修复的最新进展,本文采用文献分析方法和统计分析法,全面对比了这三届大会的论文和报告,包括参会国家、主要机构、热点矿区、修复要素、矿山类型、修复技术等。在此基础上,归纳了新开发的生态修复技术,包括植被恢复、土壤修复和景观恢复等新技术;总结了当前的研究热点,主要有复垦的土壤和修复的植物之间相互作用的机理、矿山生态修复的监测新技术、本土物种保持、污染土壤修复新技术、应对全球气候变化的矿山生态修复新思维和矿山生态系统服务价值等;介绍了会议提出的新观点,如自然恢复和人工恢复选择的新标准、矿山生态恢复力新理论、新型矿山生态系统及其设计等。最后对未来研究趋势进行了预测。  相似文献   

17.
The purpose of this study was to examine the acute effects of different vibration loads (frequency and amplitude) of whole-body vibration (WBV) on flexibility and explosive strength of lower limbs in springboard divers. Eighteen male and female divers, aged 19 ± 2 years, volunteered to perform 3 different WBV protocols in the present study. To assess the vibration effect, flexibility and explosive strength of lower limbs were measured before (Pre), immediately after (Post 1) and 15 min after the end of vibration exposure (Post 15). Three protocols with different frequencies and amplitudes were used in the present study: a) low vibration frequency and amplitude (30 Hz/2 mm); b) high vibration frequency and amplitude (50 Hz/4 mm); c) a control protocol (no vibration). WBV protocols were performed on a Power Plate platform, whereas the no vibration divers performed the same protocol but with the vibration platform turned off. A two-way ANOVA 3 x 3 (protocol × time) with repeated measures on both factors was used. The level of significance was set at p < 0.05. Univariate analyses with simple contrasts across time were selected as post hoc tests. Intraclass coefficients (ICC) were used to assess the reliability across time. The results indicated that flexibility and explosive strength of lower limbs were significantly higher in both WBV protocols compared to the no vibration group (NVG). The greatest improvement in flexibility and explosive strength, which occurred immediately after vibration treatment, was maintained 15 min later in both WBV protocols, whereas NVG revealed a significant decrease 15 min later, in all examined strength parameters. In conclusion, a bout of WBV significantly increased flexibility and explosive strength in competitive divers compared with the NVG. Therefore, it is recommended to incorporate WBV as a method to increase flexibility and vertical jump height in sports where these parameters play an important role in the success outcome of these sports.  相似文献   

18.
全球气候变化增加了滨海地区遭受侵蚀、风暴潮等灾害的风险,利用自然湿地的消浪功能增强海岸防护是当前研究的热点,但目前对消浪服务的空间分布评估研究相对匮乏。以上海市崇明岛环岛滨海湿地为例,结合GIS与Kobayashi指数形式波高衰减模型评估常规状态下湿地消浪服务的空间分布特征。结果显示,大、小潮升条件下,崇明环岛湿地消波的平均高度分别为0.94、0.54 m与效度分别为83.6%、60.4%,消波高度的空间分布表现为南岸小于北岸,消波效度的空间分布在小潮升时与消波高度相似,而大潮升时南岸的消波效度有明显提升。物理环境与生物因素空间分布及其相互作用的异质性,导致消浪服务的空间分布也具有空间异质性。实际参与消波的断面宽度与不同景观消波服务的评估结果表明,一个断面的所有景观并非都参与到消浪过程中,即使在大潮升时期,不同岸段景观的平均参与度不足71%。潮高与波高的增加并不会使参与消波的景观规模成对应比例的增加,说明消波服务在空间上具有明显的非线性特征。研究可为滨海湿地生态修复空间规划、基于生态系统的海岸带管理、自然资本核算提供科技支撑。  相似文献   

19.
To discriminate between breast cancer patients and controls, we used a three-step approach to obtain our decision rule. First, we ranked the mass/charge values using random forests, because it generates importance indices that take possible interactions into account. We observed that the top ranked variables consisted of highly correlated contiguous mass/charge values, which were grouped in the second step into new variables. Finally, these newly created variables were used as predictors to find a suitable discrimination rule. In this last step, we compared three different methods, namely Classification and Regression Tree (CART), logistic regression and penalized logistic regression. Logistic regression and penalized logistic regression performed equally well and both had a higher classification accuracy than CART. The model obtained with penalized logistic regression was chosen as we hypothesized that this model would provide a better classification accuracy in the validation set. The solution had a good performance on the training set with a classification accuracy of 86.3%, and a sensitivity and specificity of 86.8% and 85.7%, respectively.  相似文献   

20.
The objective of this study is to better understand the effect of mobile LNAPL on source-zone attenuation at sites using a statistical evaluation of 3,523 leaking underground fuel tank (LUFT) sites from GeoTracker, an extensive database of chemical release sites in California. Our analysis indicates that sites with mobile LNAPL (i.e., sites with measurable LNAPL thicknesses in one or more groundwater monitoring wells (LNAPL sites)) have higher maximum dissolved groundwater constituent concentrations and significantly slower source-zone attenuation rates (i.e., changes in maximum concentrations over time) compared to sites with a history of no measurable LNAPL thickness (non-LNAPL sites). However, the evaluation indicates that, for mobile LNAPL sites, physical recovery (skimming and bailing) does not increase source attenuation rates. The results suggest a need for more careful evaluation of the potential benefits of physical LNAPL technologies.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号