Comparative biochemical and molecular evaluation of swarming of Proteus and effects of anti-swarm agents

In addition to inadequate understanding of swarming motility and virulence of Proteus, there is paucity of information on the relative effectiveness of the various anti-swarm agents. The anti-swarming effects of urea, sodium dodecylsulphate (SDS) and trihydroxymethylglycine (Tris) on 40 clinical isolates of Proteus Spp. were comparatively investigated and plasmids associated with swarming were characterized. The three substances elicited a comparable concentration-dependent anti-swarming property at 0.25 – 1.25% on nutrient agar. Anti-swarm agents displayed heterogeneity in their ability to cause significant decreases in the expression of virulence factors. Swarm motility was further found to be strongly associated with the expression of virulence factors in these strains. Of the Proteus strains tested, 32 were found to harbour 1 – 4 plasmids of size ranging from 6.0 – 33.5 kb. Plasmid curing resulted in loss of swarming in 65.6% of these strains. In order to reduce the risk of infection with virulent Proteus strains, the laboratory use of urea and SDS is suggested. Key Words: Proteus, swarming, urea, SDS, Tris. African Journal of Biotechnology Vol.3(1) 2004: 99-10

Comparison between Oxygen (dry) and Water Vapour (wet) Attenuation from an Airborne Platform to Satellite in Nigeria

Aeronautical applications have become very important in supporting communications for inflight entertainment and in-flight connectivity services. As the local aircraft is moving from one location to the other at higher altitudes between 6 – 8 km above the sea level, the link between airborne platform and satellite undergoes signal degradation which affects internet connection for the passenger. However, cloud and gases are major tropospheric effects that cause attenuation above rain height of 5 km for radio wave propagation most importantly microwave signals for an airborne platform to space communication in the Ku and above. Therefore, the analysis and prediction of the airborne-satellite path links of gas and cloud attenuation is essential, hence the importance of this research. An historical radiosonde data obtained from National Oceanic and Atmospheric Administration (NOAA) covering three locations in Nigeria; Abuja (2006-2018), Ikeja (1966-2019), and Kano (1972-2019) at an elevation angles of 48.5 ˚, 44.5 ˚ and 48.8 ˚ respectively were used for this research. The total attenuation at V-band, both uplink and downlink frequencies follow the same pattern; at Abuja station in 2007 the total attenuation is about 2.6053 dB at 50 GHz and 0.7487 dB at 40 GHz while at Ikeja station in 1961 the total attenuation is about 3.7882 dB at 50 GHz and 1.0575 dB at 40 GHz and finally at Kano station in 1990 the total attenuation is about 5.7119 dB at 50 GHz and 1.4881 dB at 40 GHz. Hence, the results can be useful for the Nigeria meteorological Agency (NIMET) and the Nigeria Civil Aviation Authority (NCAA) in planning for a more efficient airborne – space communication for aviation safety, in-flight connectivity (IFC) and in-Flight entertainment (IFE)

Evaluation of Refractivity Gradient and k-factor within the Lower Troposphere of Maiduguri and Enugu under Two Climatic Zones in Nigeria

Estimation of radio refractivity is important in the planning and design of terrestrial radio communication links for the availability and accessibility of strong networks and signals. This paper investigates the refractivity gradient, effective earth radius factor (k), and the geo-climatic factor K in the first 1km of the troposphere of two selected stations (Maiduguri and Enugu) under different climatic zones in Nigeria. The indirect method of measuring radio refractivity was employed in this study to take measurements over the two selected stations. Vertical profile values of pressure (hPa), Temperature (°C), and Relative humidity (%) within the first 1 km were extracted from MERRA MAIMCPASM V5.20 database profile obtained from a satellite sounding instrument by NASA in the United States. MatLab programming language was used to evaluate the refractivity gradient, k-factor, and geo-climatic factor using the equations recommended by ITU. The results showed that Enugu was predominantly sub-refractive due to the tropical savannah climate while Maiduguri encountered both sub-refractive and normal refractive conditions due to the hot semi-arid climate, and unstable and extreme weather conditions in the region

Full Length Research Paper - Comparative biochemical and molecular evaluation of swarming of Proteus and effects of anti-swarm agents

In addition to inadequate understanding of swarming motility and virulence of Proteus, there is paucity of information on the relative effectiveness of the various anti-swarm agents. The anti-swarming effects of urea, sodium dodecylsulphate (SDS) and trihydroxymethylglycine (Tris) on 40 clinical isolates of Proteus Spp. were comparatively investigated and plasmids associated with swarming were characterized. The three substances elicited a comparable concentration-dependent anti-swarming property at 0.25 -1.25% on nutrient agar. Anti-swarm agents displayed heterogeneity in their ability to cause significant decreases in the expression of virulence factors. Swarm motility was further found to be strongly associated with the expression of virulence factors in these strains. Of the Proteus strains tested, 32 were found to harbour 1 - 4 plasmids of size ranging from 6.0 -33.5 kb. Plasmid curing resulted in loss of swarming in 65.6% of these strains. In order to reduce the risk of infection with virulent Proteus strains, the laboratory use of urea and SDS is suggested

Analysis of Seasonal Precipitation Rate in Nigeria Using Dataset from Tropical Rainfall Measuring Mission

The study aimed to analyze the seasonal precipitation rate using dataset retrieved from TRMM over Nigeria. The Seasons evaluated are December to February (DJF), March to May (MAM), June to August (JJA) and September to October (SON) using ten years (December 2009-November 2019) data acquired from TRMM data base. The result shows that, the precipitation rate differs and these ranges from light precipitation from the northern regions to heavy precipitation in the southern regions. For the DJF season, the northern regions experience little or no precipitation especially during the dry season. Meanwhile, during the MAM, JJA and SON seasons, the northern regions experiences light to moderate (0 ≤ R < 5 mm/h) precipitation rate according to World Meteorological Organization (WMO) while the southern regions experience moderate to heavy (0.1 ≤ R ≥ 0.5 mm/h) precipitation rate with its peak at MAM and SON seasons which correspond to the wet months/season and early dry season. It follows that the result obtained from this work is in agreement with the WMO. The result from this work will provide an insight on precipitation event which in turn, will help in decision making on various ways of adaptation and also, planning of outdoors events such as agricultural activities (food securities), sport activities and also in the telecommunication and aviation as increase in the rate precipitation increases the attenuation on communication link