Nitrogen fertilizer management strategy for oil palm-maize intercropping system in the semi-deciduous forest zone of Ghana

  In an attempt to increase yield of maize in oil palm-maize intercropping system, farmers resort to indiscriminate cutting of fronds of palms leading to low yield of oil palm. This study evaluated the impact of different N fertilizer levels on maize varieties in oil palm-maize intercropping system. The economics of nitrogen application was also studied. The treatments were: T1-Sole oil palm, T2-Oil palm+‘Omankwa’, T3-Oil palm+‘Abelehi’ and T4-Oil palm+ ‘Obatanpa’. The crop associations were superimposed with nitrogen fertilizer levels as sub-treatments at N0- N0:P0:K0, N1-N60:P60:K60, and N2-N120:P60:K60 per ha. The experiment was a split plot design with 4 replications. There was no significant difference (p< 0.05) between maize varieties across seasons for both maize yield and aboveground biomass though ‘Omankwa’ was promising across seasons and more responsive to nitrogen application. Across the three maize varieties, N60P60K60 was significantly higher (p<0.05) by 40% and 17% for maize yield and aboveground biomass respectively as compared to N0:P0:K0. The study recommends N60P60P60 fertilizer level and further states that to improve fertilizer adoption, government should subsidize fertilizer cost for farmers to purchase. The outcome of cost benefit analysis revealed that return per cash invested favored cropping system with N60:P60:K60 and season with less water stress

Hydrodynamics and gas dispersion in industrial flotation cells

Bibliography: pages [201]-212.Solids suspension and gas dispersion studies were performed on a total of 40 industrial flotation cells of various types, sizes and duties in a Platinum Group Metal (pgm) concentrator in the North West Province of South Africa. The wide variety of cells studied included a Bateman 3-m³ cell, Outokumpu 16-m³ conventional and 50-m³ TankCells, WEMCO 84, 120, 144 cells and WEMCO 144 with 164 mechanism and high-power motor. The gas phase properties of bubble size, superficial gas velocity, air holdup and bubble surface area flux were used in characterising these cells. The bubble size was measured at six different locations in the cells using the UCT Bubble Size Analyser. The superficial gas velocity and gas holdup were measured similarly with other special designed devices. The bubble surface area flux, a new parameter for characterising the hydrodynamics and gas dispersion in flotation cells, was calculated from the ratio of the superficial gas velocity to the Sauter mean bubble size. The results of these measurements were analysed in terms of key variables including air flowrate, impeller speed and location in the cell. The bubble size was found to increase with increasing air flowrate and decreasing impeller speed. Bubbles in the impeller zone were found to be smaller than bubbles in the quiescent zone due to significant bubble coalescence in this region. The bubble size was also found to be inversely related to the power consumption provided that this was expressed on an impeller-swept-volume basis. The superficial gas velocity was found to increase with increasing air flowrate and impeller speed and was significantly affected by location in the cell. Differences in superficial gas velocities were observed at constant air flowrates and at different impeller speeds. This unexpected finding was attributed to differences in flow patterns in the cells. Air holdup was found to be largely insensitive to changes in air flowrate and impeller speed in cells operating at their normal conditions. Differences in air holdup in the quiescent and turbulent zones were observed but these were more noticeable in smaller cells. The bubble surface area flux in industrial flotation cells was found to be in the range of 50-60 m²/m²/s irrespective of the type, size and duty of cell. However, it was observed that the bubble surface area flux could be varied by manipulating certain key cell variables such as the impeller speed and the air flowrate. The bubble surface area flux was found to increase with increasing air flowrate until reaching an optimum at sufficiently high air flowrates

Diatom microparticles for drug delivery applications: Impact of surface functionalisation

Nature has developed an elegant biologically based self-assembling synthetic route to produce silica biomaterials with complex 3-dimensional (3-d) porous structures, offering great potential to replace synthetic mesoporous materials as suitable drug carriers for the development of cost-effective drug delivery systems. This work presents the application of a porous silica material derived from diatoms, also known as diatomaceous earth (DE), as a drug carrier with the aim to explore the impact of surface functionalization on drug loading and release characteristics of water insoluble drugs. The surface modification on DE was performed with two silanes: 3-aminopropyltriethoxy silane (APTES) and N-(3-(trimethoxysilyl) propyl) ethylene diamine (AEAPTMS) and phosphonic acids (PA), i.e. 2-carboxyethyl-phosphonic acid (2-phos), 16-phosphono-hexadecanoic acid (16-phos), providing organic surface hydrophilic and hydrophobic properties. Differences in the loading capacity of DE (15-24%) and release time (6-15 days) were observed as results of the presence of different functional groups on the surface.M.S. Aw, M. Bariana, J. Addai-Mensah, and D. Losi

The effect of L (-) cysteine and thiourea on the kinetics of copper electrocrystallization from aqueous sulphate solutions

The production and characterization of nano-crystalline metallic coatings has been a subject of intensive research due to their fundamental and commercial significance. For instance, thin films of copper are used in electronic industry for the fabrication of interconnect for printed circuit boards, integrated chips and multilayer sandwiches. Organic substances such as thiourea (TU), gelatine, polyethylene glycol, and benzotriazole are usually added to electrodeposition bath in low concentrations for beneficial effects such as brightening and levelling of the deposit. Despite the perceived benefits of additives, there is limited fundamental understanding of their mode of action and impact on electrocrystallization kinetics. In this study, the effect of thiourea and L (-) Cysteine (CYS) on mechanisms and kinetics of copper electrodeposition from an aqueous solution at pH 1 and 25 degreesC was studied using Linear Scan Voltammetry (LSV) and Atomic Force Microscopy (AFM). The current density measurements, estimated kinetic parameters and ex situ AFM visual observation indicated that both TU and CYS have a significant inhibition and morphological effects on the electroreduction of Cu(II), resulting in fine-grained deposits. These additives were found to influence the electron and mass transfer at electrode/electrolyte interface and lead to the formation of a crystalline deposit whose structure and morphological analysis indicate S-based impurity incorporation effects

Novel treatment strategy for NRAS-mutated melanoma through a selective inhibitor of CD147/VEGFR-2 interaction

More than 70% of human NRAS melanomas are resistant to MEK inhibitors highlighting the crucial need for efficient therapeutic strategies for these tumors. CD147, a membrane receptor, is overexpressed in most cancers including melanoma and is associated with poor prognosis. We show here that CD147i, a specific inhibitor of CD147/VEGFR-2 interaction represents a potential therapeutic strategy for NRAS melanoma cells. It significantly inhibited the malignant properties of NRAS melanomas ex vivo and in vivo. Importantly, NRAS patient’s-derived xenografts, which were resistant to MEKi, became sensitive when combined with CD147i leading to decreased proliferation ex vivo and tumor regression in vivo. Mechanistic studies revealed that CD147i effects were mediated through STAT3 pathway. These data bring a proof of concept on the impact of the inhibition of CD147/VEGFR-2 interaction on melanoma progression and represents a new therapeutic opportunity for NRAS melanoma when combined with MEKi.This work was supported by La Ligue Nationale contre le Cancer, the Institut National de la Santé et de la Recherche Médicale (INSERM) and La Société Française de Dermatologie. AL was supported by a PhD funding from La Ligue Nationale contre le Cancer and the Spanish Ministry of Science and Innovation (PID2019-110167RB-I00). We thank technological platform of the Institut Recherche Saint-Louis (IRSL) for confocal microscopy analyses and Dr Benoit Souquet for technical support