382 research outputs found
Shared visiting in Equator city
In this paper we describe an infrastructure and prototype system for sharing of visiting experiences across multiple media. The prototype supports synchronous co-visiting by physical and digital visitors, with digital access via either the World Wide Web or 3-dimensional graphics
Sampling of an STT event over the Eastern Mediterranean region by lidar and electrochemical sonde
International audienceA two-wavelength ultraviolet (289?316nm) ozone Differential Absorption Lidar (DIAL) system is used to perform ozone measurements in the free troposphere in the Eastern Mediterranean (Northern Greece). The ozone DIAL profiles obtained during a Stratosphere-to-Troposphere Transport (STT) event are compared to that acquired by an electrochemical ozonesonde, in the altitude range between 2 and 10 km. The measurement accuracy of these two instruments is also discussed. The mean difference between the ozone profiles obtained by the two techniques is of the order of 1.11 ppbv (1.86%), while the corresponding standard deviation is 4.69 ppbv (8.16%). A case study of an STT event which occurred on 29 November 2000 is presented and analyzed, using ozone lidar, satellite and meteorological data, as well as air mass back-trajectory analysis. During this STT event ozone mixing ratios of 55?65 ppbv were observed between 5 and 7 km height above sea level (a.s.l.). Stratospheric air was mixed with tropospheric air masses, leading to potential vorticity (PV) losses due to diabatic processes. The ozone DIAL system can be used for following STT events and small-scale mixing phenomena in the free troposphere, and for providing sequences of vertical ozone profiles in the free troposphere. Keywords. Atmospheric composition and structure (Evolution of the atmosphere; Instruments and techniques) ? Meteorology and atmospheric dynamics (Middle atmosphere dynamics; Turbulence
A comparative study for management of fissure in ano with glycerin-trinitrate and lignocaine ointment: a randomized control trial
Background: Anal fissure is a very common benign anorectal disorder with significant morbidity among otherwise healthy individuals. Of all the patients coming to our OPD 15-20% have anal fissure. So there arises need to study the best and most compliant conservative treatment modality.Methods: Study was randomized, prospective, observational and longitudinal including 200 patients of age group 18-60 equally divided in 2 groups. Group A given 0.2% GTN ointment and group B given lignocaine ointment.Results: Better and early and sustained symptomatic relief was noted with GTN compared to lignocaine. 80% cases showed complete healing by 8 weeks with GTN compared to 52% healing with lignocaine. Headache was main side effect with GTN. Recurrence rate was high with lignocaine.Conclusions: Topical GTN has a statistically and clinically significant success rate for fissure healing and pain improvement at 8 weeks compared to lignocaine ointment (80% vs. 52%). It came at the cost of clinically acceptable level of morbidity (headache)
Evaluation of 99 pesticide residues in major agricultural products from the Western Highlands zone of Cameroon using QuECHERS method extraction and LC-MS/MS and GC-ECD analyses
There is no information available on pesticide residue levels in major food commodities harvested in Cameroon, especially from the western highlands region, the food basket of the country. Hence, this study evaluated the residues of 99 pesticides in 72 samples of 12 agricultural products collected in the region, using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method extraction, and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography with electron capture detection (GC-ECD). This method was suitable for detecting the targeted compounds: For 81 pesticides by LC-MS/MS, the limit of quantification (LOQ) was between 0.0004 and 0.0537 mg/kg; and for 18 halogenated pesticides by GC-ECD, it ranged from 0.0012 to 0.2180 mg/kg. The residues of 62 pesticides, including 12 banned compounds, were found in the samples. Insecticides (39.7%) were the most prevalent group, with all the samples containing at least one pesticide. Twenty-one pesticides (34.4%) exceeded their European Union maximum residue limits (MRLs) and 22 pesticides (34.4%) were found in all 6 sampling locations. Malathion and p,p′-DDT were the most distributed pesticides, found in almost all the samples and sampling sites. Food items with the highest rates of positive results were chili pepper (23.2%), white pepper (20.2%), kidney beans (17.3%), and soybeans (17.2%). Samples with residues above their MRLs represented 38% of all the positive analyses; chili pepper (6.4%) and kidney beans (5.5%) were found to have the most residues above their MRLs. The most critical food commodities were kidney beans, soybeans, chili pepper, and maize. This data presents scientific evidence that investigation into continuous monitoring and good regulation of pesticide usage in Cameroon is needed, and paves the way for health risks analysi
Antifungal potential of extracts from four plants against Acremonium apii and Colletotrichum dematium, two major pathogens of celery (Apium graveolens L.) in Cameroon
In order to contribute to a sustainable control of plant diseases through the use of natural compounds, the antifungal potential of 11 extracts from 4 Cameroonian plants (Ageratum conyzoides, Callistemon citrinus, Cymbopogon citratus and Ocimum gratissimum) was evaluated in vitro against Acremonium apii and Colletotrichum dematium, respectively the causal agents of brown spots and anthracnose diseases of celery (Apium graveolens L.). Inhibition of fungi mycelial growth by essential oils, ethanol and aqueous extracts was assessed by using the supplemented media technique. Essential oils exhibited comparable activities against both fungi with minimum inhibitory concentration between 400 and 6000 ppm.
Essential oil from O. gratissimum showed the highest inhibitory activity against both pathogens (400 ppm) followed by C. citratus (700 ppm and 800 ppm against A. apii and C. dematium, respectively), and then C. citrinus (6000 ppm). Ethanol extracts exhibited after the essential oils, the higher inhibitory activity against the two pathogens. Extract of C. citrinus was the most active with reductions of radial growth of 77.68% and 97.16% respectively against A. apii and C. dematium at 10000 ppm. Aqueous extracts at the same concentrations of ethanol extracts had little or no activity against both fungi. The fungitoxic potential of essential oils was higher than the one of the synthetic fungicide used as positive control. Our results suggest a promising potential of essential oils and ethanol extracts for botanicals control of celery fungal pathogens
Self-adjuvanting polymer-peptide conjugates as therapeutic vaccine candidates against cervical cancer
Dendrimers are structurally well-defined, synthetic polymers with sizes and physicochemical properties often resembling those of biomacromolecules (e.g. proteins). As a result they are promising candidates for peptide-based vaccine delivery platforms. Herein, we established a synthetic pathway to conjugate a human papillomavirus (HPV) E7 protein-derived peptide antigen to a star-polymer to create a macromolecular vaccine candidate to treat HPV-related cancers. These conjugates were able to reduce tumor growth and eradicate E7-expressing TC-1 tumors in mice after a single immunization, without the help of any external adjuvant
Antifungal potential of essential oils, aqueous and ethanol extracts of thirteen plants against Fusarium oxysporum f . sp Lycopersici and Phytophtora infestans (Mont.) de Bary as major tomato pathogens
Antifungal activity of essential oils (EO), ethanol extracts (ETE) and cold water extracts (CWE) of thirteen plants was
evaluated against Fusarium oxysporum and Phytophtora infestans causal agents of tomato Fusarium wilt and late blight diseases respectively. The supplemented media and slide germination techniques were carried out to determine the effect of extracts on the mycelial growth and conidia germination of pathogens. The results showed that essential oils exhibited the highest antifungal activity followed by ETE and CWE. Callistemon citrinus, Cymbopogon citratus and Ocimum gratissimum essential oils were the most active inhibiting completely radial growth and conidia germination of Phytophtora infestans at 312.5 and 625 µg/ml. Essential oils of Ocimum gratissimum and Cymbopogon citratus inhibited totally the radial growth and conidia germination of Fusarium oxysporum at 625 and 312.5 µg/ml respectively. ETE of Ageratum conyzoides and Callistemon citrinus were the most active inhibiting radial growth of Phytophtora infestans. Cymbopogon citratus and Ocimum gratissimum were the most active against radial growth and conidia germination of Fusarium oxysporum at 6250 µg/ml. The fungi toxic potential of some extracts was comparable to synthetic fungicides used as positive controls. Preliminary phytochemical analysis of ETE and CWE revealed that stronger inhibiting effects were recorded with extracts rich in phenols, flavonoids, tannins, and coumarins. These findings may contribute to develop new green fungicides to protect tomato from Fusarium wilt and late blight diseases
Evaluation of 99 Pesticide Residues in Major Agricultural Products from the Western Highlands Zone of Cameroon Using QuEChERS Method Extraction and LC-MS/MS and GC-ECD Analyses
There is no information available on pesticide residue levels in major food commodities harvested in Cameroon, especially from the western highlands region, the food basket of the country. Hence, this study evaluated the residues of 99 pesticides in 72 samples of 12 agricultural products collected in the region, using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method extraction, and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography with electron capture detection (GC-ECD). This method was suitable for detecting the targeted compounds: For 81 pesticides by LC-MS/MS, the limit of quantification (LOQ) was between 0.0004 and 0.0537 mg/kg; and for 18 halogenated pesticides by GC-ECD, it ranged from 0.0012 to 0.2180 mg/kg. The residues of 62 pesticides, including 12 banned compounds, were found in the samples. Insecticides (39.7%) were the most prevalent group, with all the samples containing at least one pesticide. Twenty-one pesticides (34.4%) exceeded their European Union maximum residue limits (MRLs) and 22 pesticides (34.4%) were found in all 6 sampling locations. Malathion and p,p′-DDT were the most distributed pesticides, found in almost all the samples and sampling sites. Food items with the highest rates of positive results were chili pepper (23.2%), white pepper (20.2%), kidney beans (17.3%), and soybeans (17.2%). Samples with residues above their MRLs represented 38% of all the positive analyses; chili pepper (6.4%) and kidney beans (5.5%) were found to have the most residues above their MRLs. The most critical food commodities were kidney beans, soybeans, chili pepper, and maize. This data presents scientific evidence that investigation into continuous monitoring and good regulation of pesticide usage in Cameroon is needed, and paves the way for health risks analysis
Contamination of Foods from Cameroon with Residues of 20 Halogenated Pesticides, and Health Risk of Adult Human Dietary Exposure
(1) Background: Halogenated pesticides are abundantly used in Cameroon, but there is no information on the health risk of consumers from exposure to their residues in foods. (2) Methods: Residues of 20 halogenated pesticides were determined in 11 agricultural products collected in the 3 largest cities of Cameroon using QuEChERS extraction and gas chromatography with electron capture detector (GC-ECD), and health risk from dietary exposure was assessed. (3) Results: Organochlorines pesticides aldrin, p,p’-dichlorodiphenyl-trichloroethane (DDT) and β-hexachlorocyclohexane (β-HCH) found in 85.0%, 81.9% and 72.5% of samples, respectively, were the most frequently detected. The highest average concentrations of residues were 1.12, 0.74 and 0.39 mg/kg for methoxychlor, alachlor and β-HCH, respectively, found in chilli pepper. Chili pepper (58.9%), cowpea (56.8%), black beans (56.5%) and kidney beans (54.0%) exhibited the highest residue occurrences. Levels above the European Union maximum residue limits (MRLs) were found for all the 20 pesticides, in 40.1% of the positive analyses, and the food samples contained 14 pesticides banned in Cameroon. Chronic, acute, cumulative and carcinogenic risk assessments revealed that lifetime consumption of maize, black beans, kidney beans, groundnuts and chili pepper contaminated with aldrin, dieldrin, endrin, HCB, heptachlor, o,p’-DDT, p,p’-DDD, p,p’-DDT, p,p’-DDE and β-HCH, could pose health risks. (4) Conclusion: These results show that there is an urgent need of pesticide usage regulation, effective application of pesticide bans and management of obsolete pesticide stocks in Cameroon
Sampling of an STT event over the Eastern Mediterranean region by lidar and electrochemical sonde
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