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Vegetation Composition, Forage Biomass and Soil Seed Bank of a Continuously Grazed Rangeland Site in Tropical Sub-Humid Environment, Tanzania
Get PDFMost rangelands along the agro-pastoral villages of Tanzania are yearlong grazed and at various states of degradation. These rangelands contribute to over 60% of the meat and milk production in the country. An inventory was conducted to assess the status of grazing resources in a typical agro-pastoral village of Tanzania having communal rangelands. Systematic random sampling techniques were employed whereby line transects and quadrat frame were used following standard procedures to collect samples and undertake field measurements for both vegetation and soil parameters. The vegetation cover for desirable pasture species, undesirable pasture species and litter were 67.7%, 10.5% and 9.4%, respectively. The soil bare patches covered 12.3 % of the surveyed rangeland site. The most dominant grass species were Enteropogon macrostachyus, Bothriochloa insculpta and Heteropogon contortus. Forage dry matter (DM) yield was 806.8 kg DM/ha. Tree density was 1500 trees/ha and the total canopy cover was 63.49%. Combretum collinum was the most dominant tree species. Soil bulk density, pH, organic carbon, nitrogen, phosphorus and potassium were 1.4 g/cm3, 6.3%, 1.14%, 0.09%, 0.89 mg/kg and 0.33 g/kg, respectively. A total of 11 dicotyledonous species mainly forbs and 9 monocotyledonous species including two perennial grasses were revealed from the incubated soil samples. The findings of this study demonstrate that the communal grazing areas have low pasture productivity, poor soil seed-bank and high cover of woody plants mainly bushes. In order, to improve forage biomass at the study site and elsewhere with similar environments selective bush clearing and re-seeding should be considered
Experimental Study on Early Polymer Injection Timing of Heavy Oil Reservoir in Bohai Sea
Get PDFThe polymer flooding of ordinary heavy oil reservoirs in Bohai Sea can improve the crude oil recovery by advancing the injection time of polymer flooding. The better the injection time is, the higher the enhanced recovery is, and the greater the income is. Based on Bohai Oilfield, the polymer application system was characterized in the laboratory, and then polymer flooding experiments were carried out at different times using one-dimensional core model. The results show that: 1) polymer AP-P4 can establish good mobility control ability (RF=107, RRF=28.5) under the target reservoir conditions; 2) Under the experimental conditions, the best time for polymer injection is to switch to polymer injection after 0.203PV water injection, and the oil recovery can be increased by 27.73%. Early polymer injection technology is very beneficial to polymer flooding in offshore oil fields
Ambipolar Charge Transport of PCNTC-O and PCNTC-R Cocrystals Obtained Under 1:2 and 1:1 Ratios of Donor and Acceptor
Get PDFThe efficiency of microelectronic devices depends greatly on the charge transport performance of organic semiconductors. The purpose of this work is to analyze the effect of donor-acceptor (D-A) cocrystals on the charge transport characteristics of organic semiconductors using the Marcus theory of electron transfer combined with kinetic Monte Carlo simulations. For two different cocrystals, sesquikis (benzene-1,2,4,5-tetracarbonitrile) 2-(1,3-benzothiazol-2-yl)-3-(pyren-1-yl)prop-2-eneni-trile(PCNTC-O) and ben-zene-1,2,4,5-tetracarbonitrile 2-(1,3-benzothiazol-2-yl)-3-(pyren-1-yl)pr-op-2-enenitrile(PCNTC-R) cocrystals, were investigated using 2-(benzo[d]-thiazol-2-yl)-3-(pyren-1-yl)acrylonitrile (Py-BZTCN) as the donor and 1,2,4,5-tetracyanobenzene (TCNB) as the acceptor mixed at 1:2 and 1:1 ratios, respectively. According to our calculations, PCNTC-O and PCNTC-R both exhibit bipolar charge transport behaviour with mobilities electron/hole attaining 0.0104/0.1252 and 0.0241/0.0598 cm2/Vs, respectively
Evaluation of Thrombolytic Activity of Four Bangladeshi Medicinal Plants, as a Possible Renewable Source for Thrombolytic Compounds
Get PDFFour Bangladeshi medicinal plants Sansevieria trifasciata, Justica gendarussa, Hydnocarpus kurzii and Mesua nagassarium have been investigated for their in vitro thrombolytic activity. The clot lysis activity was assessed by addition of the test material to the pre-clotted blood and incubation for 90 min. at 37oC and was expressed as % lysis of clot. Each of the plant was extracted with methanol at room temperature and the concentrated methanolic extract was fractionated by the modified Kupchan partitioning method to provide pet-ether, carbon tetrachloride, chloroform and aqueous soluble fractions. Among the four plants the aqueous soluble fraction of M. nagassarium, carbon tetrachloride soluble fraction of H. Kurzii , aqueous soluble fraction of methanolic extract of S. trifasciata exhibited highest thrombolytic activity with clot lysis value of 50.86%, 47.50%, and 47.10% respectively. However, the pet ether and carbon tetrachloride soluble fraction of methanolic extract of J. gendarussa demonstrated significant thrombolytic activity as evident from 45.93% and 45.47% lysis of clot, respectively. Standard streptokinase was used as positive control which exhibited 61.50% lysis of clot while the negative control water revealed 2.56% lysis of clot
Structural Characterization of ZS – 2A: An Antiplasmodial Compound Isolated from Zizyphus spina-christi Root Bark
Get PDFZizyphus spina-christi (Rhamnaceae) is a popular medicinal plant that grows wildly in Asia and Tropical Africa. The plant is widely used in ethnomedical practice for the treatment of fever. As a step towards the isolation of biologically active constituents of this plant, we carried out a bioassay guided extraction of the root bark using solvents of varying polarity including, hexane, chloroform, ethylacetate and methanol. An antiplasmodial compound, designated as ZS-2A, was isolated from the chloroform extract and the chemical structure of the compound was characterized using UVvisible, IR, 13C and 1H NMR and thermo-analytical techniques. Our analysis established ZS – 2A as a betulinic acid
In Vitro Efficacy Test on a Food Supplement for the Treatment of Urinary Tract Infections (UTIs)
Get PDFUrinary tract infections (UTIs) are among the most common bacterial infections, representing a massive burden on healthcare systems and accounting for significant morbidity and healthcare expenditure. As bacteria generally cause UTIs, the primary therapy is defined by antibiotics, whose wide use can cause antibiotic resistance. In this scenario, using nutraceuticals to manage UTIs is an attractive alternative.
This study aims to test the in vitro efficacy of a new food supplement for treating UTIs containing D-mannose, palmitoylethanolamide, HibCyn® (hibiscus extract), N-acetylcysteine and microencapsulated Lactobacillus rhamnosus LR04.
The activity of the product was evaluated in terms of antimicrobial, antibiofilm, cytotoxic, antiinflammatory, and synergic activity with fosfomycin with respect to the main microorganisms responsible for UTIs, specifically Klebsiella pneumoniae, Enterococcus faecium, and Escherichia coli.
“UTIVAL” food supplement has an action on both the inhibition and eradication of the biofilms formed by all the microorganisms. In the in vitro tests performed in this study, the activity of the product was effective at a concentration of 0.78 g/l.
It was also possible to affirm that the product has an inhibiting effect on inflammation mediated by tumor necrosis factor αlfa (TNFα) in a concentration range of 0.04 to 0.625 mg/ml
In Vitro Phosphate Binding Capacity of a Dietary Supplement for Dogs and Cats
Get PDFHyperphosphatemia has been recognized as a serious and frequent complication in dogs and cats with Chronic Kidney Disease (CKD). The veterinary approach is mainly based on reducing phosphorus in the diet and with phosphate (P) binders. In this in vitro study we compared seven supplements with a different combination of ingredients for dogs and cats at pH 3 and 7 to estimate the P binding capacity overtime. Our results confirmed the best binding capacity of supplements at acid compared to basic condition. The P binding capacity of two products containing mainly calcium carbonate, calcium lactate-gluconate and chitosan was higher compared to the other tested at the same conditions
Formulation and Characterization of Poly (Acrylic Acid)- Co-Chitosan Nanoparticles as pH-Thermo-Responsive System to Control Delivery
Get PDFThe present study aims to develop a pH thermosensitive nanocarriers as a drug delivery system to better controll drug release. Nanoparticles was developed by the combination of smart polymers, chitosan and poly(acrylic acid) were chosen as biodegradable vectors to encapsulate and transport the drug. The used method was based on the polymerization of acrylic acid using reticulated chitosan as a template. Analysis of particle size, Zeta potential, and size distribution revealed that most of the resulting nanoparticles had an average diameter less than 100nm, with a high Zeta potentiel about -29.7 mV and a narrow size distribution. In addition, the developed system showed an encapsulation efficiency around 97%. In vitro release test was achieved using different buffer solutions with pH equal to 1.2, 3.6, 4.2, 4.8, 6.8 and 7.4. The release profiles showed that nanoparticles provide drug protection at different pH values. They responded at pH = 3.6 and provided sustained controlled release of up to 62.62% over 8 hours. The results reveal that the prepared nanoparticles can be used as drug delivery carriers. They can improve therapeutic efficiency of the drugs used in the treatment of inflamed tissues where the pH is around 3.6 as in the Crohn disease
Geodynamics of Alpine Belt and Caribbean Region: Plate - Tectonics and Plume - Tectonics
Get PDFThe origin and evolution of geological structures reflect lithosphere-asthenosphere interaction in the process of lithospheric plate movement. Mantle diapirs contribute significantly to the sedimentary basins formation in Alpine belt and Caribbean region. Mantle diapirs are the result of density inversion in the asthenosphere–lithosphere system in the periods of tectonomagmatic activations. Increasing heat flow and mantle diapirs on the phone of convergence of Africa and Eurasia in Alpine belt and North and South Americas in Caribbean region produce intercontinental seas in the Cenozoic. The analytical solution of the problem give possibility to find the critical parameters connecting the mantle flow dynamics with surface relief evolution. In Alpine belt, the mantle diapirs form new basins at the final stage of Africa–Eurasia collision in the Cenozoic. In the Caribbean region, great mantle diapir separates the North and South Americas in the Mesozoic, and then the diapir is the source for different smaller diapirs during the convergence of these continents in the Cenozoic. The Gulf of Mexico and Pre-Caspian Depression are connected with mantle diapirs upwelling and have common geological-geophysical features as very rich oil-gas and salt bearing structures. Geodynamics of Alpine belt and the Caribbean region is determined by plume - tectonics on background of plate - tectonics in these regions
Treatment Strategies and Challenges in the Co-Management of Type 2 Diabetes and Tuberculosis
Get PDFDespite rapid advances in the healthcare field, diabetes mellitus (DM) and tuberculosis (TB) continues to be a global burden that affects millions of people every year. The association between DM and TB has been known for an extended period. The last 15 years, however, have seen an increased number of studies showing that diabetes (both type 1 and type 2) increases the risk of tuberculosis because of impaired immune defences and likewise, TB may induce hyperglycemia and therefore increase the risk of DM. When DM and TB co-exist as dual diseases, it complicates management strategies as treatment outcomes are affected. In developing countries where the epidemic of DM and TB is rapidly growing, the presence of a concomitant disease becomes a challenge to the affected nation and could also impact DM and TB control on a global scale. This review brings together information on what is currently known about T2DM and TB as a double epidemic, the recommended treatment strategies, and the challenges involved in disease management. Furthermore, we address the future perspectives of the co-management of T2DM and TB and what can be done to overcome the shortcomings of currently available guidelines