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1.
    
Cinnamaldehyde is a natural antimicrobial compound that has been found to damage the cytoplasmic membrane, inhibit septum development and cause cell elongation, as well as induce oxidative stress in Escherichia coli. Thus, cinnamaldehyde may be of value as a natural compound to enhance susceptibility of drug resistant E. coli to antibiotics in livestock production. This study examined the ability of cinnamaldehyde to increase the susceptibility of E. coli to antibiotics using the checkerboard method. Interactions between the antimicrobials were characterized using fractional inhibitory concentration (FIC) values. All tested E. coli strains were resistant to erythromycin and bacitracin but were susceptible to penicillin G and ampicillin. Strains 8WT, ATCC 23739 and 02:0627 were resistant to novobiocin and the latter two strains were also resistant to tetracycline. Cinnamaldehyde synergistically increased the susceptibility of all E. coli strains to erythromycin (FIC ≤ 0.5). Another synergistic effect between tetracycline and cinnamaldehyde was observed when tested against E. coli ATCC 23739 (FIC = 0.3). Cinnamaldehyde synergistically and additively reduced the MIC of novobiocin when tested against ATCC 23739 and 02:0627 (FIC ≤ 0.5) or 8WT (FIC = 1), respectively, suggesting that E. coli strains may respond differently to challenge by the cinnamaldehyde-novobiocin combination. With all strains, cinnamaldehyde was not effective at reducing the MIC value of bacitracin. Findings of this study suggest that cinnamaldehyde may be used in combination with several antibiotics to enhance susceptibility of drug resistant E. coli.  相似文献   

2.
    
Fusarium verticillioides is a filamentous fungus and a widely distributed pathogen having the ability to infect and cause destruction in economically important crops and grains by producing fumonisin mycotoxins. In the present study, the inhibitory effect of cinnamon, citral, Litsea cubeba oil, clove, eucalyptus, anise, spearmint and camphor oils on F. verticillioides was investigated, and cinnamon oil proves to be the most effective in inhibition. The antifungal effect of cinnamon oil was studied with special reference to its mechanism of inhibition of F. verticillioides growth at the morphological and ultrastructural levels. For F. verticillioides, the minimal inhibitory concentrations (MICs) of cinnamon oil (85% cinnamaldehyde), natural cinnamaldehyde (95%), and synthetic cinnamaldehyde (99%) were 60, 50, and 45 μL/L, respectively. The antifungal activity of cinnamon oil was proportional to its cinnamaldehyde concentration. Scanning electron microscopy and transmission electron microscopy of F. verticillioides exposed to MIC of cinnamaldehyde showed irreversible deleterious morphological and ultrastructural alterations, such as lack of cytoplasmic contents, loss of integrity and rigidity of the cell wall, plasma membrane disruption, mitochondrial destruction, folding of the cell. These modifications induced by cinnamaldehyde may be due to its interference with enzymatic reactions of cell wall synthesis, thus affecting the morphogenesis and growth of the fungus. These results further emphasized the toxicity of cinnamon oil against F. verticillioides attacking grains, and that cinnamon oil could be safely used as an alternative to chemical fungicides during grain storage and in the field.  相似文献   

3.
油藏岩石渗透率合成方法探讨   总被引:1,自引:0,他引:1  
渗透率合成在石油储量计算、油田开发方案编制、油藏数值模拟等油藏工程研究中经常遇到,主要包括垂向上不同层段渗透率的合成和沿渗流方向不同渗透率带渗透率的合成。受\"十五\"科技攻关项目\"深层高温高压凝析气藏储层应力敏感性实验与试井方法研究\"中长岩心实验研究的启发,结合石油地质、开发研究工作的具体情况,用数学推导的方法推导了两类渗透率的合成公式,并用室内实验实测数据进行了验证。  相似文献   

4.
    
《Food Control》2014,35(2):619-623
In order to select effective and safe natural antibacterial ingredients, more than 30 kinds of plant extracts were selected for their suitability as antibacterial agents. A standard broth microdilution method was used to evaluate their antimicrobial activity, a cytotoxicity test was used to detect their safety, and a synergy assay was used to determine which combinations have a synergistic effect. Then time-kill curves were used to further verify their bactericidal capacity. As a result of these tests, cinnamaldehyde and carvacrol were identified first, then subsequently verified to be the most effective and safe natural active substances. It was found that all of the tested bacteria strains were sensitive to cinnamaldehyde and carvacrol. The combination of cinnamaldehyde with carvacrol also showed good synergistic antibacterial effect against 7 of the 11 tested bacterial strains. The time-kill assay verified synergism for the cinnamaldehyde/carvacrol combination toward Escherichia coli and Staphylococcus aureus. These results indicated that the combination of cinnamaldehyde and carvacrol may serve as a promising naturally sourced food preservative with excellent bactericidal activity against common food spoilage microorganisms.  相似文献   

5.
    
Active packaging plays a promising approach to extend the shelf-life of packed fresh mushrooms without compromising the fresh status. Four different active agents were incorporated into the packaging material to extend the shelf-life of packed mushrooms: sodium metabisulphite combined with citric acid; green tea extract; cinnamon essential oil and purple carrot extract. The sulphur dioxide-based packaging maintained the mushrooms white and appealing to consumers for a longer time than conventional packaging. The release of sulphur dioxide was carefully adjusted to avoid undesirable yellowing while keeping the whitening effect. Sulphur dioxide was determined in the mushrooms after the storage period, being the resulting concentration below the current limit of 10 μg/g. Green tea extract at high concentration maintained white colour of mushrooms longer than blank samples. Cinnamon essential oil and purple carrot extracts did not show enough antioxidant properties to inhibit the spoilage of mushrooms and/or extending their shelf-life.  相似文献   

6.
We examine the calculation of relative permeability and residual saturation using networks derived from tomographic images of Fontainebleau sandstone previously used to successfully calculate single-phase transport properties. In contrast to electrical conductivity and permeability calculations, we find that that computed relative permeabilities and residual saturations for samples of the same sandstone display a high degree of variability. Randomizing pores and throats to remove all correlations almost completely eliminates the variability between samples and produces smooth numerical data sets. We conclude that correlations in rock microstructure, which appear to have little effect on the calculation of single fluid properties, have a major effect on computed relative permeability and residual saturation.  相似文献   

7.
    
Most gas distribution pipeline are located in densely populated areas and their transmission mediums are characterized by high pressure,combustibility and explosiveness,so the consequences will be quite serious once pipeline leakage happens. In order to improve the safety operation level of gas distribution pipeline,this paper carried out investigation and applicability analysis on foreign relevant laws,regulations and standards. Then,by referring to domestic and foreign successful experience in the integrity management of gas transmission,the similarities and differences between gas distribution pipeline and gas transmission were analyzed and accordingly the system structure and main content of the integrity management of gas distribution pipeline were determined. Finally,based on PetroChina's achievements in the construction practice of integrity management system,the system was verified and improved. And the following research results were obtained. First,integrity management is an effective means to ensure the safe operation of gas distribution pipeline. Second,the integrity management of gas distribution pipeline mainly includes six key links,i.e.,data acquisition & management,risk assessment,leakage management,detection & evaluation,repair & maintenance,and check & efficiency evaluation. Third,the implementation of the integrity management of gas distribution pipeline needs five support elements,including laws,regulations & standards,system documents,support technologies,system platforms and organizations. Fourth,the focuses of the integrity management shall be determined according to pressure grades. Fifth,it is recommended to embed the system documents of integrity management into the QHSE system,take the data management as the important link of system document construction and include the content of system documents into the information system. Sixth,the integrity management system shall be improved continuously. In conclusion,the research results can provide reference for the implementation of the integrity management in urban gas enterprises.  相似文献   

8.
A method was developed for classifying petroleum into four types according to their origin and integrity: marine, non-marine, degraded and thermally transformed. The method was based on the relative proportions of functional groups measured by FTIR spectroscopy. Twenty-one petroleum samples were used for model calibration and six for validation, which were pre-classified. Aliphatic functional group absorption maxima were used at 2919, 2856, 1457 and 1376 cm?1, as well as at 1700  and 811 cm?1 for aromatic groups, and at 1152 and 1030 cm?1 for polar groups (sulphonyl and ether, respectively). Using hierarchical cluster and discriminate analyses, three canonic functions were obtained that classified the samples according to their origin and integrity, with a prediction efficiency of 100%, for both calibration and validation. The canonic functions derived from the discriminate analysis had correlation coefficients of 0.994, 0.900, and 0.867, among the variables studied and the classification factor. The method is efficient for the proposed classifications and can be useful for a range of applications.  相似文献   

9.
城镇燃气管网输送介质具有高压、易燃、易爆的特点,并且大多数都位于人口密集的区域,一旦发生泄漏,则后果相当严重。为了提高城镇燃气管网的安全运行水平,通过对国外相关法规标准开展调研与适用性分析,借鉴国内外天然气长输管道完整性管理所取得的成功经验,分析了城镇燃气管网与天然气长输管道的共性和差异性,由此确定了城镇燃气管网完整性管理的体系结构和主要内容,并基于中国石油天然气股份有限公司完整性管理体系建设实践的成果,开展了体系验证和改进。研究结果表明:①完整性管理是保障燃气管网安全运行的有效手段;②城镇燃气管网完整性管理主要包括数据采集与管理、风险评价、泄漏管理、检测与评价、维修维护、考核与效能评价等6个关键环节;③城镇燃气管网完整性管理工作的落实需要法规标准、体系文件、支持技术、系统平台和组织机构等5个支持要素;④应根据不同的压力等级来确定完整性管理工作的重点;⑤完整性管理体系文件应纳入到QHSE体系,将数据管理作为体系文件建设的重要环节,将体系文件内容固化到信息系统;⑥应对完整性管理体系进行持续改进。结论认为,该研究成果可以为城镇燃气企业开展完整性管理工作提供借鉴和参考。  相似文献   

10.
为揭示超声波作用对煤岩渗透率的影响规律,基于煤岩渗透率性原理,开展超声波作用下煤样渗透率测试实验。对比分析未加超声波与不同功率超声波作用下的实测数据;与此同时,超声波的加载促进了CH4气体在煤岩中的渗流,增大了煤样的渗透率;且超声波的功率越大,煤样渗透率的提高率越大。在此基础上,通过超声波功率与气体流量比的关系,推算拟合出不同围压、不同功率下煤岩的渗透率关系模型。通过实验结果分析,详细论述了超声波提高煤层气渗透性的原理。  相似文献   

11.
依据达西定律,研制了机械式野外用微型渗透率仪(MFP)。MFP携带方便,可系统测量岩石的渗透率,对测量对象不具损坏性,既便地野外测量露头岩石,也适于在实验室测量手标本或岩心。MFP由承压气源、调制器和注气探头3部分装置组成,通过闭合作用在测量对象表面的探头,将高压气体注入岩石,测得透过岩石作用面的气体流量和相应压力,再据渗透率与它们的关系换算出渗透率数据。根据经验,用MFP每天可测量400-500  相似文献   

12.
This study proposes a new technique for cleaning deposited asphaltenes using laser energy. Two series of experiments were carried out to achieve this objective. In the first one, one-inch column of bitumen mixed with limestone was placed above powdered limestone column in a flow cell. In the second series of experiments, actual consolidated limestone cores were subjected to flow of asphaltenic crude oil to simulate the damage process (i.e. permeability reduction). Both unconsolidated and consolidated limestone samples were subjected to a laser energy using laboratory diode modules at various laser intensity and treatment time intervals.Experimental results indicated that exposure of the above-mentioned permeability damaged limestone samples to laser energy caused asphaltene disruption and resulted in recovery of damaged permeability. The increase of laser intensity increased the recovered permeability and the optimum time duration is measured to be 1 h at laser intensity of 19 mW/h. Simultaneous pumping is required during the laser treatment to avoid the re-precipitation of the disrupted asphaltene.  相似文献   

13.
储层中高渗透层段剖面连通概率计算方法   总被引:1,自引:0,他引:1  
本文阐述了储层中高渗透层段剖面连通概率的计算原理和步骤,并给出了计算实例。  相似文献   

14.
渗透率是评价煤储层渗透性的重要参数,通过对割理、有效应力、埋深等煤储层渗透率影响因素的数值模拟研究,结果表明,割理的发育程度决定了煤储层的渗透性,割理的闭合、开启程度又受到应力场的控制。  相似文献   

15.
利用测井资料评价储集层性质的探讨   总被引:2,自引:0,他引:2  
匡立春 《测井技术》1992,16(2):117-119
根据对储集层之简化导电模型的理论分析,提出了一个由电阻率、孔隙度信息表示的、反映储层性质的“孔隙结构参数S”。实际应用表明,S参数在评价储集层性质、计算储层渗透率等方面具有一定的使用价值。  相似文献   

16.
基于施工质量在管道完整性管理中的重要作用,提出对油气管道施工质量进行科学合理评价的新方法,并对影响管道施工质量的三个主要方面焊接、防腐和埋设极其相关的质量影响因素进行简要分析,根据实际情况与专家打分对某一埋地管道应用多级模糊综合评价模型对其施工质量进行综合评价,得到可靠的评价结果。对提高施工质量提出几点参考建议。  相似文献   

17.
    
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18.
    
Following the discovery of horsemeat in beef products in Europe in 2013, restoring consumers' confidence in processed meat products as well as in all the agencies involved – producers, food safety authorities, retailers – soon became a key priority. However, the European public's confidence in processed meat products and their views about government and industry actions to manage fraudulent practices in the wake of this incident are poorly understood. The objective of this study was to identify the core issues affecting consumers' confidence in the food industry, particularly in the meat processing sector, and to explore the impact of the horsemeat incident on consumers' purchasing and eating behaviour. It involved the use of an online deliberation tool VIZZATA™ to collect detailed views of 61 consumers in the UK and the Republic of Ireland. Many participants reported buying fewer products containing processed meat as a result of the horsemeat incident. These respondents also claimed that their confidence in processed foods containing meat was lower than before the incident. Participants suggested restoring consumer confidence through improved traceability, sourcing local ingredients, providing clearer and correct labelling and stating the origin of meat on pack. Overall, findings indicate that rebuilding consumer confidence in processed meat products following a food adulteration episode is a multifaceted and difficult process. Food authorities and the food industry can benefit from the insights provided by this study to address issues affecting consumer confidence and to improve their communication strategies during future food adulteration incidents.  相似文献   

19.
对低渗天然气层的地层特性进行了描述,提出低渗气层的毛细管压力是地层损害主要因素,并把它作为平衡压力钻井设计和施工所应考虑的问题,以便在钻井过程中减轻钻井液对低渗气层的损害。  相似文献   

20.
陕甘宁盆地东部低渗砂岩气藏损害机理初探   总被引:3,自引:0,他引:3  
对陕甘宁盆地东部上古生界砂岩气藏进行较系统的敏感性试验研究及损害因素分析。结果表明,该区(以下石盒子组为代表)粘土含量高,水敏及微粒迁移严重,孔喉细微,亲水性强,毛管压力高,含水饱和度高,对压力敏感,具有典型低渗砂岩气层的显著特点。水锁效应、水敏效应及微粒迁移是其主要损害原因,而压力敏感性又加剧了损害程度及克服的难度。这些损害主要与“水”有关。因此,改变钻井液完井液的性质(增强抑制性、改变润湿性质,降低表面张力等)和减少侵入量是控制其损害的主要着眼点,如何降低或缓和压力敏感性对损害的加剧作用及克服难度也应予以充分重视。  相似文献   

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