3,079 research outputs found
Determination of Soil Erosion and Sediment Yield in the Bonsa River Basin Using GIS and Revised Universal Soil Loss Equation (RUSLE)
The Bonsa river is an important tributary of the Ankobra river in the Western Region of Ghana. The catchment of the Bonsa river has been undergoing rapid land cover changes due to human activities such as farming, illegal mining, population growth, among others which are likely to promote soil erosion and sediment yield in the river basin. To estimate the amount of soil eroded over a period and subsequent sediment yielded along the Bonsa river basin, the Revised Universal Soil Loss Equation (RUSLE) was integrated with Geographic Information System (GIS) to model the spatial distribution patterns in soil erosion and sediment yield within the catchment. Data used included annual rainfall records, soil map, Digital Elevation Model (DEM) and land-use map of the study area. Parameters of the model were determined and converted into raster layers using the raster calculator tool in ArcMap to produce a soil erosion map. The concept of Sediment Delivery Ratio (SDR) was applied to determine the annual sediment yield by combining a raster SDR layer with soil erosion map. The predicted soil loss and sediment yield values were found to be low. This may be due to high soil protective cover provided by vegetation as well as low topographic relief in the river basin. Though, the elements and processes responsible for soil erosion and sediment yield prevailing in the basin was found to be low, adverse situations could be developed with time if the prevailing conditions are not checked, as soil erosion is a natural gradual slow process. The gains made could be sustained by putting measures in place to control human activities, particularly, illegal mining (galamsey) in the basin, indiscriminate cutting down of trees and farmining activities along the Bansa river basin. This study will support monitoring, planning of water resources and help to improve sustainable water quality
Thermal stability of β-lactoglobulins A and B: Effect of SDS, urea, cysteine and N-ethylmaleimide
Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used to monitor changes in the secondary structure and thermal stability of β-lactoglobulin A and B in the presence of sodium dodecyl sulphate (SDS), N-ethylmaleimide (NEM), urea and cysteine. An increase in the thermal stabilities of both proteins was noted in the presence of 10 mM-SDS. In the presence of 50 mM-SDS, there was extensive denaturation of both variants. In general, the β-strand/β-sheet regions in the secondary structure of both variants were very susceptible to denaturation by SDS and cysteine, suggesting that these regions may be held by hydrophobic and disulphide bonds. At ambient temperature and physiological pH, a notable difference was observed in the 1636 and 1627 cm -1 regions of the FTIR spectra of the two β-Ig variants. The results suggest possible differences in the nature of the β-sheet/β-strand distribution/content of the two proteins. Urea and NEM at a concentration of 50 mM, had little effect on the secondary structure and denaturation of both variants. New findings are presented which further indicate that although the β-Ig B variant showed greater thermal stability than the A variant in all the cases studied, its denaturation temperature and secondary structure were affected to a greater extent by the protein perturbants than ß-Ig A.published_or_final_versio
Food Production and Processing Considerations of Allergenic Food Ingredients: A Review
Although most consumers show no adverse symptoms to food allergens, health consequences for sensitized individuals can be very serious. As a result, the Codex General Standard for the Labelling of Prepackaged Foods has specified a series of allergenic ingredients/substances requiring mandatory declaration when present in processed prepackaged food products. Countries adhering to international standards are required to observe this minimum of eight substances, but additional priority allergens are included in the list in some countries. Enforcement agencies have traditionally focused their effort on surveillance of prepackaged goods, but there is a growing need to apply a bottom-up approach to allergen risk management in food manufacturing starting from primary food processing operations in order to minimize the possibility of allergen contamination in finished products. The present paper aims to review food production considerations that impact allergen risk management, and it is directed mainly to food manufacturers and policy makers. Furthermore, a series of food ingredients and the allergenic fractions identified from them, as well as the current methodology used for detection of these allergenic foods, is provided
Anti-nociceptive and antioxidant activities of an aqueous leaf extract of Corchorus olitorius L. (Tiliaceae)
A preliminary study had shown that C. olitorius has analgesic activity possibly mediated through opioidergic pathway. The study was a follow up work to evaluate the anti-nociceptive effects and other possible mechanisms of action of an aqueous leaf extract of C. olitorius (COE) using formalin-induced nociception test. COE was screened for its analgesic, and antioxidant activities. The anti-nociceptive effect of COE (3x10-2, 1x10-1 and 3x10-1 g kg-1, p.o), and morphine (1x10-3, 3x10-3 and 1x10-2 gkg-1, i.p.) were evaluated using the formalin-induced nociception test. The study showed that C. olitorius has analgesic activity possibly mediated through opioidergic pathway. COE produced significant (P ˂ 0.05) dose-dependent antinociceptive effects similar to morphine in both phases of formalin-induced nociception. The extract showed free radical scavenging properties and different phyto-constituents such as alkaloids, flavonoids, saponins, cardiac glycosides, tannins, anthraquinones and terpenoids were identified. COE has both central and peripheral anti-nociceptive effects mediated through opioidergic receptor activation and also partly through ATP-sensitive K+ channel activation systems. The findings confirms earlier reports, and further shows that C. olitorius produces anti-nociception by interrupting many pain processing pathways. Results further suggest that the extract (COE) might possess some chemical constituents that are responsible for the analgesic and the antioxidant activities.Keywords: Naloxone, glibenclamide, morphine, nociception, DPPH, formalin test
Multiple Linear Regression Model for Estimating the Price of a Housing Unit
This paper uses the respective unit costs, over fifteen (15) years, of selected Housing Unit Major Components (HUMC): cement, iron rods, aluzinc roofing sheets, coral paint, wood and sand, to develop Multiple Linear Regression Model (MLRM) for determining Housing Unit Price (HUP) for one-bedroom and two-bedroom housing units. In the modeling, the Ordinary Least Squares (OLS) normality assumption which could introduce errors in the statistical analyses was dealt with by log transformation of the data, ensuring the data is normally distributed and there is no correlation between them. Minimisation of Sum of Squares Error method was used to derive the model coefficients. The resultant MLRM is: Ŷi MLRM = (X'X)-1 X'Y(xi') where X is the sample data matrix. The specific model for one-bedroom housing unit is loge (HUPMLRM)1-Bed = 1.017 – 2.225 x 10-5 x CC + 2.512 x 10-6 x CS + 6.016 x 10-4 x CIR + 1.985 x 10-4 x CR + 5.694 x 10-4 x CP -7.437 x 10-4 x CW and that for two-bedroom housing unit is loge (HUPMLRM)2-Bed = 5.760 – 7.501 x 10-7 x CC + 2.935 x 10-6 x CS + 1.898 x 10-3 x CIR + 6.695 x 10-4 x CR - 9.157 x 10-3 x CP +6.136 x 10-3 x CW, where CC, CS, CIR, CR, CP and CW are costs of the total quantity of cement, sand, iron rods, roofing, paint and wood respectively. The MLRM was validated by using it to estimate the known HUP in the 15.5th year. From the results, the percentage absolute deviations of the estimated HUP from the known HUP are 1.27% and 2.02% for one-bedroom and two-bedroom housing units respectively, which are satisfactory. The novel approach presented in this paper is a valuable contribution to the body of knowledge in modeling. Keywords: Multiple Regression Analysis, Housing Unit Major Components, Housing Unit Pric
rAAV2/5 Gene-Targeting to Rods: Dose-Dependent Efficiency and Complications Associated With Different Promoters
A prerequisite for using corrective gene therapy to treat humans with inherited retinal degenerative diseases that primarily affect rods is to develop viral vectors that target specifically this population of photoreceptors. The delivery of a viral vector with photoreceptor tropism coupled with a rod-specific promoter is likely to be the safest and most efficient approach to target expression of the therapeutic gene to rods. Three promoters that included a fragment of the proximal mouse opsin promoter (mOP), the human G-protein-coupled receptor protein kinase 1 promoter (hGRK1), or the cytomegalovirus immediate early enhancer combined with the chicken β actin proximal promoter CBA were evaluated for their specificity and robustness in driving GFP reporter gene expression in rods, when packaged in a recombinant adeno-associated viral vector of serotype 2/5 (AAV2/5), and delivered via subretinal injection to the normal canine retina. Photoreceptor-specific promoters (mOP, hGRK1) targeted robust GFP expression to rods, whereas the ubiquitously expressed CBA promoter led to transgene expression in the retinal pigment epithelium, rods, cones and rare Müller, horizontal and ganglion cells. Late onset inflammation was frequently observed both clinically and histologically with all three constructs when the highest viral titers were injected. Cone loss in the injected regions of the retinas that received the highest titers occurred with both the hGRK1 and CBA promoters. Efficient and specific rod transduction, together with preservation of retinal structure was achieved with both mOP and hGRK1 promoters when viral titers in the order of 1011 vg ml–1 were used
Schistosoma haematobium co-infection with soil-transmitted helminthes: prevalence and risk factors from two communities in the central region of Ghana
Background: Schistosoma haematobium co-infection with S. mansoni and soil-transmitted helminthes afflict most-at-risk populations in endemic communities in the developing world. Aim: This study investigated S. haematobium co-infection with soil-transmitted helminthes, and host risk factors in two communities in the central region of Ghana. Methods: Schools and children were selected by stratified cluster and random sampling methods respectively. A total of 250 school children (aged 5 - > 20 years) were recruited. Teachers issued questionnaires to obtain information on host risk factors, water-contact activities and knowledge of S. haematobium infection. Urine and stool samples were examined for S. haematobium infection and S. mansoni and soil-transmitted helminthes using sedimentation quantitative and direct smear/formol-ether sedimentation concentration techniques respectively.Results: S. haematobium infection (1 - 50 eggs/10 ml urine) prevalence at Apewosika and Putubiw were 27.5 % and 17 % respectively. Males were more at risk of S. haematobium infection than females. S. haematobium co-infection with soil-transmitted helminthes (A. lumbricoides, E. histolytica, and T. trichuria) was recorded in Putubiw, with females more at risk than males. Children aged 16-19 and 10-15 were more at risk of S. haematobium infection and helminthic co-infection respectively. Haematuria and proteinuria were predictive of S. haematobium infection. School children had poor knowledge of S. haematobium infection. Water-contact activity was common.Conclusion: S. haematobium prevalence and its co-infection with soil-transmitted helminthes were common in Putubiw. Watercontact activity and poor knowledge about S. haematobium infection were major risk factors. Increased education on preventive and control measures especially in schools is recommended.Key words: Haematuria, proteinuria, Schistosoma haematobium, S. mansoni, helminthes, Bulinus globosu
Approximate square-root-time relaxation in glass-forming liquids
We present data for the dielectric relaxation of 43 glass-forming organic
liquids, showing that the primary (alpha) relaxation is often close to
square-root-time relaxation. The better an inverse power-law description of the
high-frequency loss applies, the more accurately is square-root-time relaxation
obeyed. These findings suggest that square-root-time relaxation is generic to
the alpha process, once a common view, but since long believed to be incorrect.
Only liquids with very large dielectric losses deviate from this picture by
having consistently narrower loss peaks. As a further challenge to the
prevailing opinion, we find that liquids with accurate square-root-time
relaxation cover a wide range of fragilities
Matrix Metalloproteinase 13 Is Induced in Fibroblasts in Polyomavirus Middle T Antigen-Driven Mammary Carcinoma without Influencing Tumor Progression
Matrix metalloproteinase (MMP) 13 (collagenase 3) is an extracellular matrix remodeling enzyme that is induced in myofibroblasts during the earliest invasive stages of human breast carcinoma, suggesting that it is involved in tumor progression. During progression of mammary carcinomas in the polyoma virus middle T oncogene mouse model (MMTV-PyMT), Mmp13 mRNA was strongly upregulated concurrently with the transition to invasive and metastatic carcinomas. As in human tumors, Mmp13 mRNA was found in myofibroblasts of invasive grade II and III carcinomas, but not in benign grade I and II mammary intraepithelial neoplasias. To determine if MMP13 plays a role in tumor progression, we crossed MMTV-PyMT mice with Mmp13 deficient mice. The absence of MMP13 did not influence tumor growth, vascularization, progression to more advanced tumor stages, or metastasis to the lungs, and the absence of MMP13 was not compensated for by expression of other MMPs or tissue inhibitor of metalloproteinases. However, an increased fraction of thin collagen fibrils was identified in MMTV-PyMT;Mmp13−/− compared to MMTV-PyMT;Mmp13+/+ tumors, showing that collagen metabolism was altered in the absence of MMP13. We conclude that the expression pattern of Mmp13 mRNA in myofibroblasts of invasive carcinomas in the MMTV-PyMT breast cancer model recapitulates the expression pattern observed in human breast cancer. Our results suggest that MMP13 is a marker of carcinoma-associated myofibroblasts of invasive carcinoma, even though it does not make a major contribution to tumor progression in the MMTV-PyMT breast cancer model
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