Controlled Release of Agrochemicals Intercalated into Montmorillonite Interlayer Space

Periodic application of agrochemicals has led to high cost of production and serious environmental pollution. In this study, the ability of montmorillonite (MMT) clay to act as a controlled release carrier for model agrochemical molecules has been investigated. Urea was loaded into MMT by a simple immersion technique while loading of metalaxyl was achieved by a rotary evaporation method. The successful incorporation of the agrochemicals into the interlayer space of MMT was confirmed by several techniques, such as, significant expansion of the interlayer space, reduction of Barrett-Joyner-Halenda (BJH) pore volumes and Brunauer-Emmett-Teller (BET) surface areas, and appearance of urea and metalaxyl characteristic bands on the Fourier-transform infrared spectra of the urea loaded montmorillonite (UMMT) and metalaxyl loaded montmorillonite (RMMT) complexes. Controlled release of the trapped molecules from the matrix was done in water and in the soil. The results reveal slow and sustained release behaviour for UMMT for a period of 10 days in soil. For a period of 30 days, MMT delayed the release of metalaxyl in soil by more than 6 times. It is evident that MMT could be used to improve the efficiency of urea and metalaxyl delivery in the soil

Instrumental Characterization of Montmorillonite Clay by FT-IR and XRD from J.K.U.A.T Farm, in the Republic of Kenya

Montmorillonite clay is a phyllosilicate mineral belonging to smectite clay group with a wide range of applications. This study demonstrates the Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Diffractometer (XRD) characterization of raw montmorillonite clay from J.K.U.A.T farm located in Juja, Kiambu county in the Republic of Kenya. The raw montmorillonite clays from different locations contained impurities and were subjected to mineral acids of different concentrations in order to enhance the analysis. The structural composition was carried out using FT-IR which revealed presence of various functional groups of Si-O, AL-OH and Si-O-AL as the major constituents. Mineralogical composition analysis was carried out using XRD and the patterns confirmed presence of aluminium oxide and silicon dioxide. Peaks of the resultant montmorillonite clay samples were compared with the published literature. This further confirmed the usefulness of spectroscopic technique in determination of crystalline nature of montmorillonite clay from J.K.U.A.T farm, Juja in the Republic of Kenya. Keywords: Instrumental characterization; FT-IR, XRD

A study of some fundamental physicochemical variables on the morphology of mesoporous silica nanoparticles MCM-41 type

[EN] All variables affecting the morphology of mesoporous silica nanoparticles (MSN) should be carefully analyzed in order to truly tailored design their mesoporous structure according to their final use. Although complete control on MCM-41 synthesis has been already claimed, reproducibility and repeatability of results remain a big issue due to the lack of information reported in literature. Stirring rate, reaction volume, and system configuration (i.e., opened or closed reactor) are three variables that are usually omitted, making the comparison of product characteristics difficult. Specifically, the rate of solvent evaporation is seldom disclosed, and its influence has not been previously analyzed. These variables were systematically studied in this work, and they were proven to have a fundamental impact on final particle morphology. Hence, a high degree of circularity (C = 0.97) and monodispersed particle size distributions were only achieved when a stirring speed of 500 rpm and a reaction scale of 500 mL were used in a partially opened system, for a 2 h reaction at 80 degrees C. Well-shaped spherical mesoporous silica nanoparticles with a diameter of 95 nm, a pore size of 2.8 nm, and a total surface area of 954 m(2) g(-1) were obtained. Final characteristics made this product suitable to be used in biomedicine and nanopharmaceutics, especially for the design of drug delivery systems.This study was funded partially by Departamento Administrativo de Ciencia Tecnología e Innovación–COLCIENCIAS (recipient, Angela A. Beltrán-Osuna); Ministerio de Economía y Competitividad, MINECO, research number MAT2016-76039-C4-1-R (Recipient, José L. Gómez-Ribelles); and Universidad Nacional de Colombia, grant number DIB201010021438 (Recipient, Jairo E. Perilla).Beltrán-Osuna, A.; Gómez Ribelles, JL.; Perilla-Perilla, JE. (2017). 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Phytochemical-loaded mesoporous silica nanoparticles for nose-to-brain olfactory drug delivery

Central nervous system (CNS) drug delivery is often hampered due to the insidious nature of the blood-brain barrier (BBB). Nose-to-brain delivery via olfactory pathways have become a target of attention for drug delivery due to bypassing of the BBB. The antioxidant properties of phytochemicals make them promising as CNS active agents but possess poor water solubility and limited BBB penetration. The primary aim of this study was the development of mesoporous silica nanoparticles (MSNs) loaded with the poorly water-soluble phytochemicals curcumin and chrysin which could be utilised for nose-to-brain delivery. We formulated spherical MSNP using a templating approach resulting in ∼220nm particles with a high surface porosity. Curcumin and chrysin were successfully loaded into MSNP and confirmed through Fourier transformation infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and HPLC approaches with a loading of 11-14% for curcumin and chrysin. Release was pH dependant with curcumin demonstrating increased chemical stability at a lower pH (5.5) with a release of 53.2%±2.2% over 24h and 9.4±0.6% for chrysin. MSNP were demonstrated to be non-toxic to olfactory neuroblastoma cells OBGF400, with chrysin (100μM) demonstrating a decrease in cell viability to 58.2±8.5% and curcumin an IC50 of 33±0.18μM. Furthermore confocal microscopy demonstrated nanoparticles of <500nm were able to accumulate within cells with FITC-loaded MSNP showing membrane localised and cytoplasmic accumulation following a 2h incubation. MSNP are useful carriers for poorly soluble phytochemicals and provide a novel vehicle to target and deliver drugs into the CNS and bypass the BBB through olfactory drug delivery

Short-term Financing Strategies for Donor-funded Organizations in Kenya a Case Study of Undugu Society

A Research Project Report by Wanyika Anthony M., Submitted to the Chandaria School of Business in Partial Fulfillment of the Requirement for the Degree of Master of International Business Administratio

Investigating how play is used to develop oral language in a pre- primary school in Taita Taveta county

Children have been known to have a natural desire for play. Curriculum designers have borrowed this idea and they have recommended learning of children through play. Oral language development is paramount in the early childhood curriculum stage. Scholars advocate the use of play in the development of oral language for young children. This is because play stimulates children to use oral language. It is in this pursuit that I developed an interest to learn how play is used to develop oral language in a pre-primary school in Taita Taveta County. The study adopted a qualitative case study design. Data was collected using face to face semi-structured interview guide, observation schedule and document analysis protocol. Data were analyzed systematically to get the findings. Findings revealed that teachers understood the importance of play in the development of oral language skills. The strategies of play that the teachers used were spontaneous play, role play, card games and locomotor games. It was found out that teachers valued play outside the classroom. However play was used to a little extent in the classroom. The main challenges identified included: inadequate number of teachers, inadequate play materials in the classroom and emphasis on instructional teaching more than play. It is recommended that the government employs enough teachers and provide equipment for play. It is also recommended that teachers undergo professional development so that they can acquire skills for using play-based learning. Curriculum developers may also allocate more time for play in ECE

Instrumental Characterization of Montmorillonite Clays by X-ray Fluorescence Spectroscopy, Fourier Transform Infrared Spectroscopy, X-ray Diffraction and UV/visible Spectrophotometry

Montmorillonite (MMT) clay has properties that would find applications in biotechnological and biomedical fields. In this study, naturally occurring MMT clay was purified using sedimentation and centrifugation techniques. Characterization of the prepared materials was done using X-ray Florescence (XRF), Fourier Transform-Infrared Spectroscopy (FT-IR Spectroscopy), UV-Visible Spectrophotometry (UV/VIS Spec) and X-ray Diffraction Spectrometry (XRD). XRF showed chemical composition of clay containing Fe2O3 as a major component. The structural composition as revealed using FT-IR, confirmed presence of various functional groups of Si-O, Al-OH and Si-O-Al as the major constituents. UV/VIS Spec confirmed presence of chromophores which absorbed light in the range of 270-300 nm confirming FT-IR results. XRD diffraction patterns confirmed presence of MMT clay as a major component with illite clay mineral existing as impurity. The sample contained good quality MMT clay and this study further confirmed the usefulness of spectroscopic techniques in determination of crystalline nature of montmorillonite clay