418 research outputs found
New model for inorganic pollutants dissipation on the northern part of the romanian black sea coast
© 2018, Editura Academiei Romane. All rights reserved. Last decades, pollution became one of the significant issues worldwide. Atmospheric pollution has a negative impact on the population health, especially in the urban agglomeration, where the exceedance of the concentration limits of the toxic gases is recorded. Sulphur dioxide is the inorganic pollutants most spread in the atmosphere in industrial areas. One of these areas is situated in Northern part of the Romanian Black Sea Coast. Therefore, we aim at determining a model for SO2 dissipation, based on the data collected at six locations, as a function of the atmospheric variables
Assessment of heavy metals in roadside dust along the Abu Dhabi–Al Ain National Highway, UAE
© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Concentrations of key heavy metals (Pb, Zn, Cd, Ni, Cr, Mn, As, and Hg) have been investigated in roadside dust collected from Abu Dhabi–Al Ain National Highway in UAE. The heavy metals contents were analyzed by atomic absorption spectrometer. Heavy metal levels varied widely from 227.9 to 2765, 19 to 1540, 37.4 to 398.6, 20.1 to 123, 0.3 to 0.7, 0.1 to 0.9, 0.1 to 0.7, and 0.1 to 0.5 mg/kg for Mn, Cr, Zn, Pb, Cd, Hg, Ni, and As, respectively. The spatial distribution pattern showed that different sources of roadway metal emissions dominate at specific locations. Peaks in heavy metal concentrations were frequently observed in locations with high traffic volume, road intersections and junctions, gas and bus stations. Decreased levels of heavy metals were measured in locations with low traffic loadings and in close proximity to farm and forest areas. In addition to traffic-related heavy metals, emissions from fossil fuel and industries remain of significance. Natural sources, through regular dust storms, are important contributors to the observed metal levels. Enrichment factor indicated that As and Ni were entirely originated from crustal sources. Cd, Zn, Pb, and Mn were moderately enriched and are probably derived from mixed sources (traffic flows, gas stations, construction and agricultural activities, among others). Road dust was significantly enriched in Cr and Hg indicating their dominant anthropogenic origin. The average geo-accumulation index values suggested that road dust are uncontaminated with Mn, Ni, and As, uncontaminated to moderately contaminated with Zn and Pb, and moderately contaminated with Cr, Cd, and Hg. The contamination factors indicated very highly contaminated road dust with Cr and Hg, considerably contaminated with Cd, and moderately contaminated with Mn, Zn, and Pb. Results of ecological risk assessment revealed that all heavy metals in road dust pose low risk to local ecosystems, except for Cd and Hg, which constitute potentially considerable risk and high risk, respectively
Baseline marine investigation and impact of fish farming on the marine environment in Jebel Ali, Dubai, United Arab Emirates
© 2020 Scattered seashells were observed on the seabed with no marine corals. The baseline studies indicate that biodiversity decreased from the northeast to southwest direction. The dominant groups of phytoplankton were diatoms followed by dinoflagellates, with insignificant vertical variations in species composition and population due to shallow water. The benthic diversity over the majority of the study area was relatively low compared with other nearshore areas in the region. All subtidal habitats showed evidence of disturbance to varying degrees, with no fish species recorded at these locations. The soft sediment habitat was found to cover much of the area footprint, and faunal diversity was very low. Fish diversity and abundance were equally poor with only a few demersal species recorded. No evidence of coral colonization was recorded although the presence of a low-profile, encrusting species was recorded in close proximity, to the east of the study area. Mangrove, coral, and seagrass were absent in the study area and its immediate vicinity. Modelling of waste plume suggested that the harbor water is fairly well-mixed, and the dispersion of ammonia attenuates with distance
Improved optical activation of ion-implanted Zn acceptors in GaN by annealing under N2 overpressure
We investigated the properties of ion-implanted GaN:Zn annealed under various conditions using photoluminescence (PL) and high resolution x-ray diffraction (HRXRD). Epitaxial GaN/sapphire of high optical quality was ion-implanted with a 1013 cm−2 dose of Zn+ ions at 200 keV. The sample was capped with 200 Å of SiNx and then diced into numerous pieces which were annealed under varied conditions in an attempt to optically activate the Zn. Annealing was performed in a tube furnace under flowing N2, an atmospheric pressure MOCVD reactor under flowing NH3 or N2, and under an N2 overpressure of 190 atm. The observed improvement in the optical quality of GaN:Zn annealed under N2 overpressure yields further insights into the trade-off between defect annealing and N loss from the GaN crysta
An unusual presentation of erythema multiforme in a paediatric patient
Background: Erythema multiforme (EM) is an acute, vesiculobullous disease of skin and mucous membranes with symptoms ranging from mild to severe. A complex interaction of different factors has been implicated the condition; the majority with a preceding herpes simplex infection. This report describes an unusual presentation of erythema multiforme affecting the lips and oral mucosa of a healthy 7-year-old boy in the form of lip adherence. Case report: Two weeks following eruption of oral ulcerations, a 7-year-old healthy boy developed severe erosive ulceration of both lips, causing complete lip adherence. This was accompanied by marked bilateral submandibular and cervical lymphadenopathy, tremor and sweating. Clinical and laboratory investigations led to a diagnosis of erythema multiforme. The patient was treated initially with gentle application of Vaseline between the lips using cotton buds in an attempt to release lip adhesion, followed by surgical release of the lips under general anaesthesia. Analgesics and topical steroid mouthwash were provided. Follow-up: Seven months later, the patient presented with a recurrence of his EM which included lesions on the skin. The patient was treated with antivirals, topical and systematic steroids to suppress the recurrent attacks of EM. Eighteen months following the initial presentation the patient and parent reported considerable decrease in the frequency, severity and duration of the occurrence of intra-oral ulcers, with no major episode of target lesions on the skin. Conclusion: Erythema multiforme is rare in children, however it should be considered in the differential diagnosis of recurrent erosive oral ulcerative lesions especially when the oral lesions resemble those of primary herpetic gingivostomatitis
A Low Cost Automated Weather Station for Real Time Local Measurements
In this paper, we present an automated weather station for real time and local measurements, based on an embedded system that continuously measures several weather factors such as temperature, humidity, barometric pressure, wind speed, wind direction, and rainfall. This weather station consists of two parts which are located indoor and outdoor and connected together wirelessly. The outdoor weather station measures the current temperature, humidity, barometric pressure, wind speed, wind direction and recent rain amount. The indoor station displays the outdoor reading as well as the temperature and humidity for the room it is located in, on a graphic liquid crystal display. In addition, this weather information can be accessed from any place through an iOS and Android application called Blynk
Use of remote sensing data in assessment land cover changes, land use patterns and land capabilities in AL-Qassim region, Saudi Arabia
© 2017 by International Journal of Ecology & Development. The Qassim region of central Saudi Arabia is one of the most important agricultural regions in the country especially for date cultivation. In the present study, Land sat TM and ETM+ data for the period 1999-2013 are used to study the land use, land cover changes in the area. Satellite images from path/row 168/042 constitute the study area. Three major land use/land cover classes are considered: hilly areas (364,407 ha), vegetated land (1,776,698 ha), and sand dunes (1,523,669 ha). The vegetated land constitutes the class 1, which is comprised of the wades mainly devoted used for for date production. Sand dunes are designated the class 11 and covered a large portion of the study area whereas the Hilly areas are unproductive and constitute as class 111.The vegetative land are surrounded by sand dune which is the most fragile system of the area and leads to damage some productive lands in the area. It is necessitates to study the area for suitable land management practices and for possible approach to stop the sand drifting or sand encroachment in the area. The land use capabilities classification of the study area includes three main classes: LUC I, LUCII, and LUC III. Slopes ranging between 0°and 20°correspond to areas that areflat, gently undulating, undulating, rolling, strongly rolling, moderately steep and steep, respectively. The slope categories dictate the usage patterns of the lands in the study area, which range from suitable to unsuitable to productive lands
EFFECT OF A BINARY BLEND COMPOSED OF POLOXAMER AND PVP ON AQUEOUS SOLUBILITY OF GRISEOFULVIN
Objective: The aim of this study was to improve the aqueous solubility of a poorly water soluble drug griseofulvin.Methods: To accomplish this goal a technique of solid dispersion with polyvinyl pyrolidone (k30) and poloxamer 407 was used. Solubility of griseofulvin alone and the solid dispersion were performed in 10 ml purified water and measured spectrophotometricaly atλ max 295 nm to detect the coefficient of improvement.Results: Solubility of griseofulvin alone was found to be 0.812 mg and the solubility of solid dispersion ranged from1.64 to 9.56 mg. After generating polynomial models correlating the variables using a D-Optimal mixture design, an optimal formulation with desired response was proposed by the statistical package. For validation, a new solid dispersion formulation based on the optimized composition was prepared and tested for solubility of griseofulvin. The optimized solid dispersion formulation enhances the solubility of griseofulvin by about 12 folds. Increase the amount of poloxamer in the optimized formulation increases the griseofulvin solubility to about 6 folds more than the optimized form.Conclusion: solid dispersion technique in conjunction with statistical design was shown to be very efficient for the optimization and improvement of aqueous solubility of poorly soluble drugs.Â
Long-term trends in ambient fine particulate matter from 1980 to 2016 in United Arab Emirates
© 2019, Springer Nature Switzerland AG. This paper presents the most comprehensive datasets of ambient fine particulate matter (PM 2.5 ) for the UAE from 1980 to 2016. The long-term distributions of PM 2.5 showed the annual average PM 2.5 concentrations constantly exceeded the EPA and WHO guidelines. They varied from 77 to 49 μg/m 3 with an overall average of 61.25 μg/m 3 . While the inter-annual variability in PM 2.5 concentrations showed relatively a cyclic pattern, with successive ups and downs, it broadly exhibited an increasing trend, particularly, over the last 14 years. PM 2.5 concentrations displayed a strong seasonal pattern, with greatest values observed during warm summer season, a period of high demand of electricity and dust events. The lowest values found in autumn are attributable to reduced demand of energy. Decreased atmospheric temperatures and high relative humidity coinciding with this period are likely to reduce the secondary formation of PM 2.5 . The spatial changes in PM 2.5 concentrations exhibited gradual downward trends to the north and northeast directions. Airborne PM 2.5 is prevalent in the southern and western regions, where the majority of oil and gas fields are located. PM 2.5 /PM 10 ratio indicated that ambient aerosols are principally associated with anthropogenic sources. Peaks in PM 2.5 /CO ratio were frequently observed during June, July, and August, although few were concurrent with March. This indicates that secondary formation plays an important role in PM 2.5 levels measured in these months, especially as the photochemical activities become relatively strong in these periods. The lowest PM 2.5 /CO ratios were found during September, October, and November (autumn) suggesting a considerable contribution of primary combustion emissions, especially vehicular emissions, to PM 2.5 concentration. PM 2.5 concentrations are positively correlated with sulfate levels. In addition to sea and dust aerosols, sulfate concentration in the coastal region is also related to fossil fuel burning from power plants, oil and gas fields, and oil industries. The population-weighted average of PM 2.5 in UAE was 63.9 μg/m 3 , which is more than three times greater than the global population-weighted mean of 20 μg/m 3
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