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排序方式: 共有1818条查询结果,搜索用时 15 毫秒
71.
Catarina Almeida-Ferreira Rafael Silva-Teixeira Ana Cristina Gonalves Carlos Miguel Marto Ana Bela Sarmento-Ribeiro Francisco Caramelo Maria Filomena Botelho Mafalda Laranjo 《International journal of molecular sciences》2022,23(3)
Breast cancer (BC) is a malignant neoplasia with the highest incidence and mortality rates in women worldwide. Currently, therapies include surgery, radiotherapy, and chemotherapy, including targeted therapies in some cases. However, treatments are often associated with serious adverse effects. Looking for new options in BC treatment, we evaluated the therapeutic potential of cold atmospheric plasma (CAP) in two cell lines (MCF7 and HCC1806) with distinct histological features. Apoptosis seemed to be the most prevalent type of death, as corroborated by several biochemical features, including phosphatidylserine exposure, the disruption of mitochondrial membrane potential, an increase in BAX/BCL2 ratio and procaspase 3 loss. Moreover, the accumulation of cells in the G2/M phase of the cell cycle points to the loss of replication ability and decreased survival. Despite reported toxic concentrations of peroxides in culture media exposed to plasma, intracellular peroxide concentration was overall decreased accompanying a reduction in GSH levels shortly after plasma exposure in both cell lines. In HCC1806, elevated nitric oxide (NO) concentration accompanied by reduced superoxide levels suggests that these cells are capable of converting plasma-derived nitrites into NO that competes with superoxide dismutase (SOD) for superoxide to form peroxinitrite. The concomitant inhibition of the antioxidative activity of cells during CAP treatment, particularly the inhibition of cytochrome c oxidase with sodium azide, synergistically increased plasma toxicity. Thus, this in vitro research enlightens the therapeutic potential of CAP in the treatment of breast cancer, elucidating its possible mechanisms of action. 相似文献
72.
73.
Carbon dioxide (CO2) is one of the commonly emitted gaseous by-products in industrial processes. While CO2 gas is the main cause to greenhouse effect, various CO2 capture technologies have been proposed and implemented to sequester the CO2 before the waste gases being released into the atmosphere. One of the mature technologies for CO2 absorption is by using amine-based solvents. In this regard, different single amine solvents or blended amine solvents have been proven for their capability to remove CO2. However, the dissolution and reaction of CO2 gas with the amine solvents turn the solution corrosive. Such phenomenon is undesired as it posts corrosion problem to the absorption column, which normally built of carbon steel material. Henceforth, understanding the behaviour of different amine-based solvents in absorbing CO2 and its subsequent impact on carbon steel corrosion is very significant. In this review article, we will outline some of the more commonly used solvents and their respective advantages and disadvantages, motivating further investigation into the corrosion tendency. Meanwhile, existing gaps in this research area are discussed for future investigation. 相似文献
74.
本试验采用新型热导检测器,分别用净化空气、高纯空气和高纯氮气作为变压器油中溶解气体在线监测装置的载气情况进行了验证。结果表明:高纯氮气是理想的载气,在高纯氮气获取方便的区域,使用经济成本低且实用性更高。 相似文献
75.
同位素测年新发展:81Kr测定古老地下水年龄理论 总被引:5,自引:0,他引:5
自从1966年Loosli&Oeschchger测定出大气中的81Kr,就已经有人设想放射性81Kr(半衰期为(2.29±0.11)×105年)可能成为测定古老地下水年龄(105~106年)的有效工具。但一直没有付诸实践,直到2000年,Collon等人首次利用81Kr同位素确定澳大利亚大自流盆地(GAB)的古老地下水年龄。本篇文章中主要介绍了影响81Kr同位素测年的因素,81Kr的取样制样分析过程,回旋加速质谱仪分析81Kr同位素的原理。 相似文献
76.
R.R. Reddy K. Narasimhulu L. Siva Sankara Reddy K. Raghavendra Kumar Y. Nazeer Ahammed 《The International journal of environmental studies》2013,70(2):247-265
Measurements of surface ozone and its precursor gases (NOx and CO) have been made at a semi‐arid site Anantapur (14.62°N, 77.65°E, 331 m asl) in tropical Indian region for the period, 2001–2003. NOx and CO levels were the highest during morning and late night hours at this site. Diurnal variations of ozone concentrations varied from 25 ppbv to 50 ppbv and were observed to increase gradually after sunrise, attaining a maximum value by the evening and decreasing gradually thereafter. During monsoon months, the diurnal amplitude of ozone was found to be small (20–25 ppbv). Seasonal variation in ozone showed a pronounced maximum (40–50 ppbv) in the winter and summer. Local pollutants were major contributors to the ozone levels during this period. Ozone shows a yearly mean mixing ratio of about 35.9 ± 8.8 ppbv. The daytime concentration of CO and NOx varied between 200 to 1200 ppbv and 3 to 20 ppbv respectively for the period studied. Annual average mixing ratios of oxides of nitrogen (NOx) and CO were observed to be 3.9±0.6 ppbv and 436±64 ppbv, respectively. 相似文献
77.
Nitrogen gas distributions in sediment pore water were determined for cores collected in Lake Erie and two nearby harbors. Concentrations of N2 gas ranged from 11.9 to 37.0 ml l−1 and from 8.9 to 58.3 ml l−1 for open lake and polluted harbor sediments, respectively. Maximum concentrations in the harbor sediments were as high as 3.5 times N2 saturation calculated for the overlying water. Indirect diffusive flux estimates for nitrogen gas ranged from 20 to 32% of the particulate nitrogen sedimentation rate in Lake Erie. At one location, the amount of nitrogen gas lost by diffusion was calculated to be greater than the nitrogen deposited to the sediments. Nitrogen gas production and diffusive loss from surficial sediments probably represents a major pathway for nitrogen removal from Lake Erie. 相似文献
78.
武汉地铁二号线越江隧道勘察设计和施工过程中存在若干工程地质问题和施工重难点,主要有两岸有害气体、浅层砂土是否液化、盾构机障碍物和江中联络通道冻结法施工等。围绕如何正确评价及合理解决上述关键问题,做到即要极大降低施工风险又需有效避免工程浪费,通过标准贯入试验、地下水流速流向测试、有害气体探测等原位测试方法,结合地质学理论分析,从综合液化判别、地下水参数取值、障碍物和有害气体地质预测及工程处理措施等多方面提出科学建议,为设计和施工提供了详实的地质依据。 相似文献
79.
Estimation of greenhouse gas emissions from municipal wastewater treatment systems in India 下载免费PDF全文
Greenhouse gas (GHG) emissions generated from municipal wastewater treatment plants in India is estimated in this study. The emissions from the wastewater treatment process as well as from the electricity used during the treatment process are estimated by using the methodology of Intergovernmental Panel on Climate Change. The present treatment plants of capacity 15 997 million litres per day (MLD) contributes towards GHG emissions of 7.3 Mt of CO2‐eq/year. The future GHG emissions would depend upon the treatment technology used for treating 34 109 MLD of untreated wastewater. The highest GHG emissions would occur if all new wastewater treatment plants are based on upflow anaerobic sludge blanket technology, 19.66 Mt CO2‐eq/year and lowest if sequential batch reactor technology is adopted, 2.93 MtCO2‐eq/year. 相似文献
80.
High performance membrane electrode assemblies (MEAs) with low noble metal loadings (NMLs) were developed for solid polymer electrolyte (SPE) water electrolysis. The electrochemical and physical characterization of the MEAs was performed by I–V curves, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Even though the total NML was lowered to 0.38 mg cm−2, it still reached a high performance of 1.633 V at 2 A cm−2 and 80 °C, with IrO2 as anode catalyst. The influences of the ionomer content in the anode catalyst layer (CL) and the cell temperature were investigated with the purpose of optimizing the performance. SEM and EIS measurements revealed that the MEA with low NML has very thin porous cathode and anode CLs that get intimate contact with the electrolyte membrane, which makes a reduced mass transport limitation and lower ohmic resistance of the MEA. A short-term water electrolysis operation at 1 A cm−2 showed that the MEA has good stability: the cell voltage maintained at ∼1.60 V without distinct degradation after 122 h operation at 80 °C and atmospheric pressure. 相似文献