259 research outputs found
An Assessment of Vegetal Cover Transition in the Zugurma Sector of Kainji Lake National Park, Nigeria
In Nigeria, National Parks and other categories of protected areas have played a major role in modern systems of biodiversity conservation and it is likely to be an important component of national biodiversity conservation strategies in the future. This research work aimed at assessing the vegetal cover transition in Zugurma Sector of Kainji Lake National Park using satellite-derived data. Satellite imageries of 1986, 2000 and 2010 were downloaded from GLCF and classified using ArcGIS, while evaluation of the agricultural resource in the study area was done using Normalized Difference Vegetation Index (NDVI); to comprehend the socioeconomic and human impact on the flora dynamics, questionnaires and interviews were used; and mathematical modeling was used to project the study area to the year 2020. Various softwares (ArcGIS 10.1, SPSS 10.0, Microsoft Office Excel, 2007 and Microsoft Office Word, 2007) were used. The results show that there is significant decrease in the forest cover between 1986 â 2010, while farmlands around the forest experienced an increase in year 2000 but reduced again in 2010. As for settlements, we have more cases of immigration, while the bare lands in and around the forests reduce or increase based on climatic aberrations, soil erosion and human activities. NDVI maps were used to show the changes in the vegetation indices for Zugurma in 1986, 2000 and 2010 derived from the classified satellite imageries. These changes ranged from 0.473684 to 0.503106 then to 0.491525 respectively (for high NDVI values); this suggests that the forest had degraded probably caused by deforestation or climatic factors. The low NDVI values as shown by the maps are -0.0616327, -0.386773 and -0.118644 for 1986, 2000 and 2010 respectively. It is projected that by the year 2020, Forests will have a percentage of 32.878% (from70.52%), while farmlands are expected to increase to 25.815% (from11.34%), Settlements to 29.259% (from 12.85%), and Bare lands will be the least with about 12.048% (from 5.29%).In order to reduce the human pressure on the KLNP, there is a need for constant dialogue and collaboration between the Park authority and the communities around the study area. This constant interaction will facilitate mutual understanding and guarantee sustainable park management. The Nigerian government should enhance biodiversity protection by incorporating biodiversity concerns into development planning, expand and consolidate protected area networks. Keywords: Biodiversity, National Park, Geographic Information System, Vegetation Inde
Isolation and characterisation of microorganisms contaminating herbal infusion sold in Minna, Nigeria
The microbiological assessment of ten herbal infusion samples from ten different locations in Minna, Niger State was investigated. The assessment of the microbial contamination on the herbal products was carried out, using standard methods. Pour plate method was used to cultivate serially diluted portions of the medicinal plant infusion samples. The results revealed that all the herbal preparations had the presence of microbial contaminants. The total heterotrophic counts of the different herbal samples ranged from 0 cfu/mL to 25.0 Ă 108cfu/mL while the total fungal counts ranged from 3.0Ă106cfu/mL to 3.5Ă108cfu/mL. The total viable bacteria counts showed that the highest counts of 25.0 Ă 108cfu/mL was recorded in the sample from Bosso and the least counts of 0 cfu/mL from Kasuwan-Gwari while the total fungal counts showed that the highest count of 3.5Ă108cfu/mL was found in the sample obtained from FUT campus and the least counts of 3.0Ă106cfu/mL in the sample from Mai-Kunkele. One way analysis of variance (ANOVA) showed that there was significant difference (p<0.05) in the microbial load of the herbal infusions from each location. The microbial isolates identified were E. coli, Staphylococcus aureus, Shigella sp, Klebsiella sp, Pseudomonas sp, Micrococcus sp, Salmonella sp, Aspergillus sp, Penicillium sp and Saccharomyces cerevisaie. Members of the genus Aspergillus were found to be predominant. This suggests that the herbal infusion harbors microorganisms that could be hazardous to human health and hence producers should maintain the highest possible level of hygiene during the processing and packaging of the products in order to ensure safety of the products
Usefulness and limitations of pollen characters in environmental studies based on Viola L. species (sect. Melanium Ging.)
The aim of these studies was to determine the effect of environmental pollution on pollen development. Pollen heteromorphism (the presence of pollen morphs differing in aperture number in one flower of a plant), pollen viability (stainability) and pollen grain size in European metallophytes from sect. Melanium Ging. (Viola L., Violaceae) were analyzed by SEM and histochemical staining.Plantsâ tolerance to heavy metals is positively correlated with their pollen viability, which should be termed stainability as it depends on the staining method applied and is not correlated with pollen germination. Abortive pollen can be produced as an effect of heavy metals but also may result from hybridization, a very common phenomenon in pansies. Pollen stainability in hybrids can be high (even exceeding 70%) or low (barely above 20%), and stainable pollen grains can differ greatly in size (from very small to giant), indicating a cytological imbalance resulting from disturbed meiosis. The number of pollen apertures is an adaptive character in facultative metallophytes. Plants from a metallicolous population produced a wider range of aperture number (3, 4, 5) than plants from a non-metallicolous population, which developed only 4- and 5-aperturate pollen. Three-aperturate longer-lived pollen are favored in the harsh conditions of a metal-polluted environment
Description of Transport Tunnel in Haloalkane Dehalogenase Variant LinB D147C+L177C from Sphingobium japonicum
The activity of enzymes with active sites buried inside their protein core highly depends on the efficient transport of substrates and products between the active site and the bulk solvent. The engineering of access tunnels in order to increase or decrease catalytic activity and specificity in a rational way is a challenging task. Here, we describe a combined experimental and computational approach to characterize the structural basis of altered activity in the haloalkane dehalogenase LinB D147C+L177C variant. While the overall protein fold is similar to the wild type enzyme and the other LinB variants, the access tunnels have been altered by introduced cysteines that were expected to form a disulfide bond. Surprisingly, the mutations have allowed several conformations of the amino acid chain in their vicinity, interfering with the structural analysis of the mutant by X-ray crystallography. The duration required for the growing of protein crystals changed from days to 1.5 years by introducing the substitutions. The haloalkane dehalogenase LinB D147C+L177C variant crystal structure was solved to 1.15 angstrom resolution, characterized and deposited to Protein Data Bank under PDB ID 6s06
Precision mass measurements on neutron-rich rare-earth isotopes at JYFLTRAP - reduced neutron pairing and implications for the -process calculations
The rare-earth peak in the -process abundance pattern depends sensitively
on both the astrophysical conditions and subtle changes in nuclear structure in
the region. This work takes an important step elucidating the nuclear structure
and reducing the uncertainties in -process calculations via precise atomic
mass measurements at the JYFLTRAP double Penning trap. Nd, Pm,
Sm, and Gd have been measured for the first time and the
precisions for Nd, Pm, Eu, Gd, and
Tb have been improved considerably. Nuclear structure has been probed
via two-neutron separation energies and neutron pairing energy metrics
. The data do not support the existence of a subshell closure at .
Neutron pairing has been found to be weaker than predicted by theoretical mass
models. The impact on the calculated -process abundances has been studied.
Substantial changes resulting in a smoother abundance distribution and a better
agreement with the solar -process abundances are observed.Comment: 8 pages, 4 figures, accepted for publication in Physical Review
Letter
Selective Modulation of α5 GABAA Receptors Exacerbates Aberrant Inhibition at Key Hippocampal Neuronal Circuits in APP Mouse Model of Alzheimerâs Disease
Selective negative allosteric modulators (NAMs), targeting α5 subunit-containing GABAA receptors (GABAARs) as potential therapeutic targets for disorders associated with cognitive deficits, including Alzheimerâs disease (AD), continually fail clinical trials. We investigated whether this was due to the change in the expression of α5 GABAARs, consequently altering synaptic function during AD pathogenesis. Using medicinal chemistry and computational modeling, we developed aqueous soluble hybrids of 6,6-dimethyl-3-(2-hydroxyethyl) thio-1-(thiazol-2-yl)-6,7-dihydro-2-benzothiophene-4(5H)-one, that demonstrated selective binding and high negative allosteric modulation, specifically for the α5 GABAAR subtypes in constructed HEK293 stable cell-lines. Using a knock-in mouse model of AD (APPNLâF/NLâF), which expresses a mutant form of human amyloid-ÎČ (AÎČ), we performed immunofluorescence studies combined with electrophysiological whole-cell recordings to investigate the effects of our key molecule, α5-SOP002 in the hippocampal CA1 region. In aged APPNLâF/NLâF mice, selective preservation of α5 GABAARs was observed in, calretinin- (CR), cholecystokinin- (CCK), somatostatin- (SST) expressing interneurons, and pyramidal cells. Previously, we reported that CR dis-inhibitory interneurons, specialized in regulating other interneurons displayed abnormally high levels of synaptic inhibition in the APPNLâF/NLâF mouse model, here we show that this excessive inhibition was ânormalizedâ to control values with bath-applied α5-SOP002 (1 ÎŒM). However, α5-SOP002, further impaired inhibition onto CCK and pyramidal cells that were already largely compromised by exhibiting a deficit of inhibition in the AD model. In summary, using a multi-disciplinary approach, we show that exposure to α5 GABAAR NAMs may further compromise aberrant synapses in AD. We, therefore, suggest that the α5 GABAAR is not a suitable therapeutic target for the treatment of AD or other cognitive deficits due to the widespread neuronal-networks that use α5 GABAARs
Compressed gas domestic aerosol valve design using high viscous product
Most of the current universal consumer aerosol products using high
viscous product such as cooking oil, antiperspirants, hair removal cream
are primarily used LPG (Liquefied Petroleum Gas) propellant which is
unfriendly environmental. The advantages of the new innovative
technology described in this paper are:
i. No butane or other liquefied hydrocarbon gas is used as a propellant
and it replaced with Compressed air, nitrogen or other safe gas
propellant.
ii. Customer acceptable spray quality and consistency during can lifetime
iii. Conventional cans and filling technology
There is only a feasible energy source which is inert gas (i.e.
compressed air) to replace VOCs (Volatile Organic Compounds) and
greenhouse gases, which must be avoided, to improve atomisation by
generating gas bubbles and turbulence inside the atomiser insert and the
actuator. This research concentrates on using âbubbly flowâ in the valve
stem, with injection of compressed gas into the passing flow, thus also
generating turbulence.
The new valve designed in this investigation using inert gases has
advantageous over conventional valve with butane propellant using high
viscous product (> 400 Cp) because, when the valving arrangement is
fully open, there are negligible energy losses as fluid passes through the
valve from the interior of the container to the actuator insert. The use of
valving arrangement thus permits all pressure drops to be controlled,
resulting in improved control of atomising efficiency and flow rate,
whereas in conventional valves a significant pressure drops occurs
through the valve which has a complex effect on the corresponding
spray
Bathymetric Survey and Volumetric Analysis for Sustainable Management: Case Study of Suleja Dam, Niger State, Nigeria
Ocean floor and the shape of the shoreline are major influencers of the changes in tidal propagation. Bathymetry; a survey operation aimed at determining the nature of the underwater level and topography of a water bodyâs bed level plays a cogent role in the determination of both the shape of the shoreline and the ocean floor thereby aiding the monitoring and spatio-temporal modelling of the changes in tidal propagation as much as it ensures the availability of hydro-data which is the foundation of a Maritime Database Management System (MDBMS). This work presents the findings of the bathymetric survey and volumetric analysis of Suleja Dam located in the North central Region of Nigeria. The Differential Global Positioning System receiver (DGPS) (Promark 3), automatic level, echomap 50s in conjunction with the engine boat were used during this research. The data acquired was processed using the GNSS solutions software with the chart plotted in surfer 9 software environment. The surface area of the dam was discovered to be 24.64ha less than the designed area. Also the volume of water was found to be 3.6 x 106m3 in contrast to the design volume of 34.7x106m3. It was also observed that the lowest water depth was 0.56m and the highest water depth was 22.06m, therefore a difference of 5.94m was obtained as against the initial construction depth of 28.00m. The undulating nature of the reservoir bed and the difference in volume of water and surface area covered by the dam are pointers and clear indications of sedimentation and siltation process going on in the dam. Keywords: Bathymetry, sounding, chart, reservoir, MDBM
Intrinsic coagulation pathway-mediated thrombin generation in mouse whole blood
Calibrated Automated Thrombography (CAT) is a versatile and sensitive
method for analyzing coagulation reactions culminating in thrombin
generation (TG). Here, we present a CAT method for analyzing TG in
murine whole blood by adapting the CAT assay used for measuring TG
in human plasma. The diagnostically used artificial and physiologic factor
XII (FXII) contact activators kaolin, ellagic acid and polyphosphate (polyP)
stimulated TG in murine blood in a dose-dependent manner resulting in
a gradual increase in endogenous thrombin potential and peak thrombin,
with shortened lag times and times to peak. The activated FXII inhibitor
rHA-Infestin-4 and direct oral anticoagulants (DOACs) interfered with TG
triggered by kaolin, ellagic acid and polyP and TG was completely attenuated
in blood of FXII- (F12â/â) and FXI-deficient (F11â/â) mice. Moreover,
reconstitution of blood from F12â/â mice with human FXII restored impaired
contact-stimulated TG. HEK293 cell-purified polyP also initiated FXII-driven
TG in mouse whole blood and addition of the selective inhibitor PPX_112
ablated natural polyP-stimulated TG. In conclusion, the data provide a method
for analysis of contact activation-mediated TG in murine whole blood. As the
FXII-driven intrinsic pathway of coagulation has emerged as novel target for
antithrombotic agents that are validated in mouse thrombosis and bleeding
models, our novel assay could expedite therapeutic drug development
Spatio-Temporal Transmission Patterns of Black-Band Disease in a Coral Community
Transmission mechanisms of black-band disease (BBD) in coral reefs are poorly understood, although this disease is considered to be one of the most widespread and destructive coral infectious diseases. The major objective of this study was to assess transmission mechanisms of BBD in the field based on the spatio-temporal patterns of the disease
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