The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Roy M Harrison - One of the best experts on this subject based on the ideXlab platform.
-
Major Component composition of pm10 and pm2 5 from roadside and urban background sites
Atmospheric Environment, 2004Co-Authors: Roy M Harrison, Alan M Jones, Royston G LawrenceAbstract:Abstract Using dichotomous Partisol samplers, airborne particulate matter has been collected and analysed as PM 2.5 and PM 10 . The instruments were deployed at four sets of paired roadside and urban background locations, three in London and one in Birmingham (UK) and the sampling protocols aimed to give equal weight to all seasons of the year. In addition to determination of sample mass, concentrations have been determined for Major chemical Components as follows: sulphate, nitrate, chloride, organic carbon, elemental carbon, iron and calcium. The measured concentrations have been converted to equivalent quantities of ammonium sulphate, ammonium nitrate (in PM 2.5 ), sodium nitrate (in PM 2.5–10 ), sodium chloride, elemental carbon, carbon compounds, gypsum and iron-rich dusts. The mass of strongly bound water has also been calculated following the mass closure methodology of Harrison et al. (Atmos. Environ. 37 (2003) 4927). Examination of the difference between roadside (mean 34.7 μg m −3 PM 10 ) and corresponding urban background (mean 23.2 μg m −3 PM 10 ) samples indicates average mass increments of 11.5 μg m −3 of PM 10 and 8.0 μg m −3 of PM 2.5 for the four site pairs, and that the roadside particle increment is comprised very largely of elemental carbon, organic compounds and iron-rich dusts. The Major Component composition lies somewhere between that reported as typical of the eastern and western US. A comparison with PM 2.5 and PM 15 sampled in Leeds (UK) in 1982 shows a decline in all Major constituents except mineral dusts (PM 2.5 only). In a comparison of data for days with PM 10 above the EU 24-h Limit Value of 50 μg m −3 with data from all days, the Component showing the greatest ratio between high pollution days and all days is fine particle nitrate.
-
Major Component contributions to pm10 composition in the uk atmosphere
Atmospheric Environment, 2000Co-Authors: Alan B Turnbull, Roy M HarrisonAbstract:Abstract Physical and chemical characteristics of PM10, including chloride, nitrate, sulphate, and black smoke, have been measured on a seasonal basis at four coastal, rural, and urban sites across the UK. Weekly campaigns with 6 h sample resolution were conducted, and the results related to meteorological conditions and air mass back trajectories. Seasonal and location- specific mean values are reported, along with an indication of diurnal characteristics. Although the urban site reflected generally higher values for the anthropogenic pollutants, long-range transport of primary and secondary particles was significant. The data have been analysed using a four-Component multi-linear regression model including black smoke as a surrogate for primary combustion particles, secondary particles (sulphate and nitrate), chloride, and a constant which describes “other”, mainly coarse mode particles. Regression coefficients have been calculated on a site and seasonal basis. “Other” particles were higher during the summer and in the urban environment with an overall mean value of 5 μg m−3. Secondary nitrate and sulphate were strongly related to meteorological conditions and less to location. Overall, the four-Component model accounts quite well ( r 2 =0.76 for all data) for PM10 mass and for some sites and seasons gives an excellent fit to the data. Addition of dummy variables representing season, urban/rural location and time of sampling gives an improvement in fit, with r 2 =0.84 . Application of the coefficients derived from the “all data” model shows secondary particles contributing 28–35% of site-mean PM10, primary combustion particles from 20 to 57%, sodium chloride, 11–34% and “other”, mainly crustal particles, 3–21%. It is felt that this probably underestimates the crustal contribution, but the reasons are unclear.
Sean F. O'keefe - One of the best experts on this subject based on the ideXlab platform.
-
Antioxidant activities of Vine Tea (Ampelopsis grossedentata) extract and its Major Component dihydromyricetin in soybean oil and cooked ground beef
Food Chemistry, 2015Co-Authors: Liyun Ye, W. N. Eigel, Hengjian Wang, Susan E. Duncan, Sean F. O'keefeAbstract:Antioxidant activities of Ampelopsis grossedentata extract (EXT) and its Major Component dihydromyricetin (DHM) were analysed and compared with BHA in two model systems, soybean oil and cooked ground beef. Oxidation of soybean oil samples was measured using peroxide value, anisidine value, headspace volatiles and headspace oxygen content. TBARS (thiobarbituric acid reactive substances) test was used to measure the oxidation of cooked beef. DHM was more potent than BHA in preventing soybean oil oxidation. EXT was not as effective as BHA or DHM in soybean oil. In cooked beef, all three antioxidants significantly lowered oxidation compared to control, but there were no differences between the three. Mechanisms and potentials of EXT and DHM as natural food antioxidants need to be studied on a case-by-case basis.
Nicola Mascolo - One of the best experts on this subject based on the ideXlab platform.
-
tanshinone iia a Major Component of salvia milthorriza bunge inhibits platelet activation via erk 2 signaling pathway
Journal of Ethnopharmacology, 2014Co-Authors: Francesco Maione, Elisabetta Caiazzo, Laura De Martino, Carla Cicala, Nicola MascoloAbstract:Abstract Ethnopharmacological relevance The roots of Salvia milthorriza Bunge (Lamiaceae) known as “Danshen”, are used in Traditional Chinese Medicine as a remedy for activating blood and eliminating stasis. TIIA, a diterpenoid of Salvia milthorriza, is one of active Components in Danshen that exhibits a significant improvement of the blood flow in the coronary circulatory system and a reduction of myocardial infarction. However, its effect on platelet and underlying mechanism remains largely unknown. On this basis, this compound could be a promising agent to improve blood viscosity and microcirculation and to prevent CVD. Materials and methods In order to investigate the effects of TIIA on platelet functionality and its interaction with various platelet activation pathways, rat PRP were incubated with TIIA for 1 min at 37 °C prior the addition of the stimuli (ADP or collagen). Aggregation was monitored in a light transmission aggregometer measuring changes in turbidity with continuous observation up to 10 min after the addition of the stimuli. MAPK signaling pathway and tubulin acetylation were analyzed by a Western blot technique. The effect of the TIIA was also studied in vivo on bleeding time in mice. Results TIIA selectively inhibited rat platelet aggregation induced by reversible ADP stimuli (3 μM) in a concentration-dependent manner (0.5–50 μM). Nevertheless, TIIA was less active against the irreversible stimuli induced by ADP (10 μM) and collagen (10 μg/mL). Moreover, experiments performed on platelet lysates collected at different time-point after the addition of the stimuli shown that TIIA modulated tubulin acetylation and inhibited Erk-2 phosphorylation. Concomitantly, TIIA administrated i.p. at 10 mg/kg significantly amplified the mice bleeding time with an increase of 58% compared to its control (2.06±0.29 min vs 1.30±0.07). ASA was used as reference drug for in vitro and in vivo experiments. Conclusions This study clarifies the intracellular signaling pathway involved in antiplatelet action of TIIA and also gives preliminary evidences for its anticoagulant activity. On this basis, this compound could be a promising agent to improve blood viscosity and microcirculation and to prevent CVD.
S. M. A. Abidi - One of the best experts on this subject based on the ideXlab platform.
-
Cysteine protease is a Major Component in the excretory/secretory products of Euclinostomum heterostomum (Digenea: Clinostomidae)
Parasitology Research, 2014Co-Authors: P. A. Ahammed Shareef, S. M. A. AbidiAbstract:Cysteine proteases of parasite organisms play numerous indispensable roles in tissue penetration, feeding, immunoevasion, virulence, egg hatching and metacercarial excystment. They are critical key enzymes in the biology of parasites and have been exploited as serodiagnostic markers, therapeutic and vaccine targets. In the present study, the cysteine proteases in the in vitro released excretory/secretory (E/S) products of the digenetic trematode parasite, Euclinostomum heterostomum have been analysed. The encysted progenetic metacercariae of E . heterostomum collected from the infected liver and kidney of Channa punctatus were excysted in vitro and incubated in phosphate buffer at 37 ± 1 °C, and the E/S products released were analysed. The spectrophotometric analysis of the proteases revealed active hydrolysis of chromogenic substrate, azocoll, in a time-, temperature- and pH-dependent manner. Optimum activity was observed at pH 7.0 at 37 ± 1 °C, and with 1 mM each of various protease inhibitors (Mini Protease Inhibitor Cocktail, ethylene diaminetetraacetic acid, phenyl methyl sulphonyl fluoride, iodoacetamide and 1,10-phenanthroline) used, significant inhibition was observed by iodoacetamide and 85 % of inhibition at a concentration of 2 mM, suggesting that cysteine protease is a Major Component in the E/S of this parasite. Four discrete protease bands of M_r 36, 39, 43 and 47 kDa were identified by gelatin-substrate zymography. Maximum gelatinolytic activity was observed at pH 7.0, and among various inhibitors used, almost complete disappearance of protease bands was observed by 2 mM iodoacetamide. The proteolytic cleavage of bovine serum albumin, bovine haemoglobin and human haemoglobin in vitro were also studied.
John A Carver - One of the best experts on this subject based on the ideXlab platform.
-
gallic acid is the Major Component of grape seed extract that inhibits amyloid fibril formation
Bioorganic & Medicinal Chemistry Letters, 2013Co-Authors: Tara L Pukala, Ian F Musgrave, Danielle M Williams, Francis C Dehle, John A CarverAbstract:Abstract Many protein misfolding diseases, for example, Alzheimer’s, Parkinson’s and Huntington’s, are characterised by the accumulation of protein aggregates in an amyloid fibrillar form. Natural products which inhibit fibril formation are a promising avenue to explore as therapeutics for the treatment of these diseases. In this study we have shown, using in vitro thioflavin T assays and transmission electron microscopy, that grape seed extract inhibits fibril formation of kappa-casein (κ-CN), a milk protein which forms amyloid fibrils spontaneously under physiological conditions. Among the Components of grape seed extract, gallic acid was the most active Component at inhibiting κ-CN fibril formation, by stabilizing κ-CN to prevent its aggregation. Concomitantly, gallic acid significantly reduced the toxicity of κ-CN to pheochromocytoma12 cells. Furthermore, gallic acid effectively inhibited fibril formation by the amyloid-beta peptide, the putative causative agent in Alzheimer’s disease. It is concluded that the gallate moiety has the fibril-inhibitory activity.
