258 research outputs found
An investigative study of Diffusion of Commercial Aspirin (Acetylsalicylic acid) in Sodium Hydroxide Solution at 25oC
Diffusion is a macroscopic motion of components of a system that arises from concentration difference. Reaction diffusion is widely used to model developmental process. This project considers effective mechanism leading to effective diffusion coefficient. A mathematical formalism for transforming local transport law into diffusive terms is developed. The diffusion coefficient of drug aspirin was studied in basic NaOH of concentration range 0.01 to 0.1M at 25oC. The rate of diffusion was monitored by observing the boundary conditions of the indicator between the drug and solution. In the study five (5) aspirin tablets collected from a local pharmacy in Eldoret town were used for the study. From the profile it was observed that as the time progressed the boundary increased fast for non-coated tablets compared to the coated ones. All the aspirin were found to give values according to underlying mechanism. For the drug A (600mg) of aspirin the best value of diffusion coefficient of 1.69 x 10-4 cm2 sec-1 was observed while the values for coated drug E with 75 mg aspirin was found to be slightly lower. Fickian mechanism is believed to be the consequence of drug molecule small size. First of all fractional drug uptake is linear and independent of the sample of thickness when In [NaOH] is plotted against square distance. A graph of x2 against In [NaOH] was plotted which was used to calculate the diffusion coefficient. The experimental values of diffusion coefficient D were within the experimental error to those of (4Dt)-1. The study also adopted a descriptive case study; it was conducted at Kimumu municipality, Eldoret town. The target population consisted of 25 respondents. Data was collected using self-administered questionnaires and interview schedules, coded and analysed using SPSS version 16.0. Systematic quantitative review data was analysed using means and frequency tables and percentages while qualitative data was analyzed using inferential statistics chi-square. Data was presented using table, pie charts and graphs. The study found that most of the individuals preferred drug B. Keywords: Diffusion, Aspirin, Acetylsalicylic acid, Diffusion Coefficient, Sodium Hydroxide, Fickian Mechanism, Systematic Revie
Reflections on law and development: Papers presented at the seminar on Law and development, University of Nairobi 26th - 30th July 1976
Microscale generation of entangled photons without momentum conservation
We report, for the first time, the generation of entangled photon pairs via
type-0 spontaneous parametric down conversion in an ultra-thin wafer of lithium
niobate in which momentum between the pump photon and daughter photons is not
conserved. The characteristics of the emission are investigated using several
techniques. We find that non-phase matched SPDC is a promising source of
ultra-broadband two photon radiation that exhibits remarkably tight correlation
widths in both the spatial and temporal domains.Comment: 9 pages, 8 figure
Preharvest Management Strategies and Their Impact on Mycotoxigenic Fungi and Associated Mycotoxins
Mycotoxigenic fungi that contaminate grain crops can lead to reduced grain quality, crop yield reduction and mycotoxicosis among humans and livestock. Preharvest management of fungi and mycotoxin contamination is considered among the most important mitigating strategies. Approaches include the breeding of resistant cultivars, use of microorganisms chemical control, production practises and the management of plant stressors. Resistant plants provide an effective and environmentally sound strategy to control mycotoxigenic fungi and mycotoxins; and have been documented. Their incorporation into commercial cultivars is, however, slow and complex. Therefore, emphasis should be placed on determining the resistance of cultivars and landraces currently used by producers. Chemical control has been successfully used for wheat; yet little to no research has been done on other important crops. Biological control strategies have focussed on Aspergillus flavus that produces aflatoxins and infects commercially important crops like maize and groundnuts. Commercial biological control products have been developed and field-tested in several African countries with promising results. The impacts of production practises are unclear under variable environmental conditions; but subsequent disease manifestation and mycotoxin contamination can be reduced. Each preharvest approaches contribute to managing mycotoxigenic fungi and their mycotoxins but integrating approaches may provide more effective management of fungal and mycotoxin contamination in crops
Diffusion of Aspirin (ASA) Based Drugs in Sodium Hydroxide Solution at Ambient Temperature.
Diffusion is a macroscopic motion of components of a system that arises from concentration difference and plays a vital role in drug migration in the body governed by Fickian diffusion laws. This project considers effective mechanism leading to effective diffusion coefficient. The diffusion coefficient of aspirin based drugs was studied in basic NaOH of concentration range 0.01M to 0.1M and a relatively more concentrated set ranging from 0.1M to 1.0M were studied at 25oC. The study looks into the rate of diffusion of coated and non-coated aspirin drugs in aqueous NaOH solution designated different letter heads A, B, C, D, and E. The objective of this work was to determine the diffusion coefficients of aspirin drugs at different concentrations range at 25oC and to compare with those calculated from limiting ionic conductance at infinite dilution. The rate of diffusion was monitored by observing the boundary conditions of the indicator between the drug and solution. The problem statement is that there are various aspirin based drugs in the market and all have different amount of aspirin in them. The research sought to find out the rate of diffusion of the drugs and conclude if at all their values relate to their masses as per the diffusion law. In the study five (5) aspirin tablets collected from a local pharmacy in Eldoret town were used for the study. From the profile it was observed that as the time progressed the boundary increased fast for noncoated tablets compared to the coated ones. The boundary heights (x) at a time t and concentration are also recorded. The moving boundary method coefficients ranged from 2.780 x 10-6 cm2 sec-1 to 6.995 x 10-6 cm2 sec- 1, 2.196 x 10-6 cm2 sec-1 to 6.092 x 10-6 cm2 sec-1, 2.138 x 10-7 cm2 sec-1 to 6.576 x 10-7 cm2 sec-1 , 3.241 x 10-10 cm2 sec-1 to 1.617 x 10-10 cm2 sec-1 and 1.378 x 10-10 cm2 sec-1 to 2.172x 10-10 cm2 sec-1 for drugs aspirin A , B, C. D and E respectively. All the aspirin were found to give values according to Fickian mechanism. For the drug A (600mg) of aspirin the best value of diffusion coefficient of 6.995 x 10-6 cm2 sec-1 at concentrated solution and 2.780 x 10-6 cm2 sec-1 was observed at dilute range solutions while the values for coated drug E with 75 mg aspirin was found to be slightly lower. The fractional drug uptake is linear and independent of the sample of thickness when distance is plotted against time. A graph of x2 against time was plotted which was used to calculate the diffusion coefficient. The experimental values of diffusion coefficient Do were in close agreement with the expected value from infinite dilution which was a general estimation of diffusion coefficients. Quantitative data was analysed using analysis of variance and chi-square statistical. Data was presented using table and graphs. The study found that the aspirin drug with the highest diffusion coefficient is drug A. In addition, conductometric technique was recommended to give more accurate results and similar method should be constituted with the use of other techniques such as TLC and spectrophotometric method for comparison purposes with the free diffusion and it is important for manufacturers to revalidate steps in the production process, for any critical control point in the production process leads to hydrolysis of aspirin. Key words: Diffusion, Aspirin, Acetylsalicylic acid, Diffusion Coefficient, Sodium Hydroxide, Fickia
Rhizobia contribute to salinity tolerance in common beans (Phaseolus vulgaris L.)
Rhizobia are soil bacteria that induce nodule formation on leguminous plants. In the nodules, they reduce dinitrogen to ammonium that can be utilized by plants. Besides nitrogen fixation, rhizobia have other symbiotic functions in plants including phosphorus and iron mobilization and protection of the plants against various abiotic stresses including salinity. Worldwide, about 20% of cultivable and 33% of irrigation land is saline, and it is estimated that around 50% of the arable land will be saline by 2050. Salinity inhibits plant growth and development, results in senescence, and ultimately plant death. The purpose of this study was to investigate how rhizobia, isolated from Kenyan soils, relieve common beans from salinity stress. The yield loss of common bean plants, which were either not inoculated or inoculated with the commercial R. tropici rhizobia CIAT899 was reduced by 73% when the plants were exposed to 300 mM NaCl, while only 60% yield loss was observed after inoculation with a novel indigenous isolate from Kenyan soil, named S3. Expression profiles showed that genes involved in the transport of mineral ions (such as K+, Ca2+, Fe3+, PO43−, and NO3−) to the host plant, and for the synthesis and transport of osmotolerance molecules (soluble carbohydrates, amino acids, and nucleotides) are highly expressed in S3 bacteroids during salt stress than in the controls. Furthermore, genes for the synthesis and transport of glutathione and γ-aminobutyric acid were upregulated in salt-stressed and S3-inocculated common bean plants. We conclude that microbial osmolytes, mineral ions, and antioxidant molecules from rhizobia enhance salt tolerance in common beans
Idealised EPR states from non-phase matched parametric down conversion
Entanglement of high dimensional states is becoming increasingly important
for quantum communication and computing. The most common source of entangled
photons is spontaneous parametric down conversion (SPDC), where the degree of
frequency and momentum entanglement is determined by the non-linear interaction
volume. Here we show that by reducing the length of a highly non-linear
material to the micrometer scale it is possible to relax the longitudinal phase
matching condition and reach record levels of transverse wavevector
entanglement. From a micro-sized layer of lithium niobate we estimate the
number of entangled angular modes to be over 1200. The entanglement is measured
both directly using correlation measurements and indirectly using stimulated
emission tomography. The high entanglement of the state generated can be used
to massively increase the quantum information capacity of photons, but it also
opens up the possibility to improve the resolution of many quantum imaging
techniques.Comment: 5 pages, 5 figure
The cobalt(II) salt of the azo dye Orange G
Crystallizing the cobalt(II) salt of the azo dye Orange G from water was found to give the solvent-separated ion-pair species hexaaquacobalt(II) 7-oxo-8-(2-phenylhydrazin-1-ylidene)-7,8-dihydronaphthalene-1,3-disulfonate tetrahydrate, [Co(H2O)6](C16H10N2O7S2)·4H2O. The asymmetric unit of the cobalt(II) salt contains three independent octahedral [Co(OH2)6]2+ cations, three azo anions, all with similar configurations, and 12 uncoordinated water molecules. The structure is closely related to that of one of the known magnesium analogues. Both structures have Z′ = 3, feature nearly planar azo anions [maximum displacement of azo-N atoms from the plane of the phenyl ring = 0.058 (7) Å] in their hydrazone tautomeric form, form layer structures with hydrophilic and hydrophobic layers alternating along the b-axis direction, and are stabilized by an extensive network of hydrogen bonds.
The Contribution of Healthcare Workers’ Knowledge on Use of Integrated Palliative Care Approach in the Management of Chronic and Life Threatening Diseases at Kakamega County Referral Hospital, Kenya
Integrated Palliative care approach (IPCA) is an approach that aims to improve the quality of life of people and their families facing the problems associated with life-threatening illness, through the prevention and relief of suffering. However, the use of IPCA in Kenya is low due to lack of access to medicines, technologies and infrastructure. The main objective was to investigate the use of IPCA in the management of chronic diseases at Kakamega County Referral Hospital (KCRH). The study design was a descriptive cross sectional with the quantitative approach. A questionnaire was administered to participants and the data analysis using SPSS. P-value was set at < 0.05. Of the total 196 Health Community Workers (HCWs) selected, a response rate of 95 % (186/196) was register. It showed that 50% males were less likely to have used IPCA as compared to their female counterparts (OR=0.5, 95% CI: 0.3-0.9) and 90% nurses were less likely to practice IPCA as compared to RCOs and MOs (OR=0.1, 95%CI: 0.1-0.5). The overall hypothesis test on the association between knowledge and performance was not significant (OR=1.6; 95% CI: 0.7 – 3.6, P<.2). The best managed symptoms by majority of respondents were severe diarrhea, anxiety and depression while the poorly managed areas were pain assessment and treatment of dyspnea. In conclusion, the HCWs were knowledgeable about IPCA but few utilized IPCA in managing terminal illnesses. Therefore, is a need to improve the HCWs’ skills and performance, increase funding, and improve infrastructure and coordination of use of IPCA
PiMA Survey Design and Methodology
The Politics and Interactive Media in Africa (PiMA) project investigates participation in radio and television programmes through new information and communication technologies (ICTs) as it is shaped by the political, social and media context in Zambia and Kenya, as well as the implications of such interactions for democratic governance and poverty alleviation. The empirical research combines different methodologies, including interviews with key informants, focus groups with audience members, in-studio observations and surveys of the general population. This paper describes the methodology for conducting surveys in four sites in Kenya and Zambia. The objective of the surveys was to obtain representative samples of two constituencies per country. Constituencies were selected according to their social and economic characteristics, in order to capture a wide variety of contexts. A random procedure was deployed in all stages of sampling, ensuring representativity of households and individuals of voting age in the four constituencies. The results of the survey can be generalised to the particular constituencies with a margin of error of approximately minus or plus 5% for a 95% confidence interval
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