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Search Results: 1 - 10 of 1881 matches for " Raphael Kwaku Klake "
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Synthesis and Conformational Studies of Some Metacyclophane Compounds  [PDF]
Louis Korbla Doamekpor, Vincent Kodzo Nartey, Raphael Kwaku Klake, Takehiko Yamato
International Journal of Organic Chemistry (IJOC) , 2012, DOI: 10.4236/ijoc.2012.22023
Abstract: Various [3.3.3]metacyclophane derivatives were synthesized from 6,15,24-tri-tert-butyl-9,18,27-trimethoxy [3.3.3] metacyclophane-2,11,20-trione 1 using simple chemical reactions. The conformations of the synthesized compounds were studied using mainly solution Proton Nuclear Magnetic Resonance (1H NMR) spectroscopic methods. Two of the synthesized compounds 5, 6, were found to have a partial cone conformation with the third, 4, having the cone conformation. Detailed variable temperature Proton Nuclear Magnetic Resonance studies further confirmed the partialcone conformation for the two products, 5, 6. During the variable temperature nuclear magnetic resonance spectroscopic studies, 6,15,24-tri-tert-butyl-9,18,27-trimethoxy[3.3.3]metacyclophane-2,11,20-triol was found to have a coalescence temperature of about 0?C.
Correlation between Heavy Metals in Fish and Sediment in Sakumo and Kpeshie Lagoons, Ghana  [PDF]
Raphael Kwaku Klake, Vincent Kodzo Nartey, Louis Korbla Doamekpor, Kenneth A. Edor
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.39125
Abstract: Concentrations of heavy metals (Cd, Pb, Mn, Zn, and Cu) were measured in bottom sediment and the black-chin tilapia (Sarotherodon melanotheron) from the Sakumo and Kpeshie lagoons using Atomic Absorption Spectrometry (AAS). Results for the levels of these metals in the sediments and fish were compared with WHO guideline values. It was observed that heavy metal concentrations in sediments of Sakumo lagoon were higher than those of Kpeshie lagoon. Among the metals, Cu and Zn were found to be highly concentrated in the fish but lower than the World Health Organization (WHO) recommended values. Spearman correlation coefficient study showed significant correlation coefficients between Pb and Zn (0.937) and between Cu and Mn (0.613) at 0.05 levels.
Synthesis and Conformational Studies on [3.3.3]Metacyclophane Oligoketone Derivatives, and Their Metal Ion Recognition  [PDF]
Louis Korbla Doamekpor, Raphael Kwaku Klake, Vincent Kodzo Nartey, Takehiko Yamato, Oti Gyamfi, Dennis Adotey
International Journal of Organic Chemistry (IJOC) , 2015, DOI: 10.4236/ijoc.2015.52014
Abstract: Chemical reactions were used to synthesize 2,11,20-tris(ethanedithia)-9,18,27-trimethoxy-6,15, 24-tri-tert-butyl[3.3.3]metacyclophane 2 and 2,11-bis(ethanedithia)-9,18,27-trimethoxy-6,15,24-tri-tert-butyl[3.3.3]metacyclophane 4 from 6,15,24-tri-tert-butyl-9,18,27-trimethoxy[3.3.3]meta-cyclophane-2,11,20-trione 1 and -2,11-dione 3. The yields of 2 and 4 were 70% and 81% respectively. The conformations of the synthesized compounds 2 and 4 were studied using mainly solution Proton Nuclear Magnetic Resonance (1H NMR) spectroscopic methods. Compounds 2 and 4 were found to have a partial-cone conformation. Detailed variable temperature Proton Nuclear Magnetic Resonance studies further confirmed the partial-cone conformation for the two products, 2, 4. During the variable temperature nuclear magnetic resonance spectroscopic studies, compound 2 was found to have a coalescence temperature of about 0?C. Extraction of silver ions with compound 2 gave an extractability of 82% while the parent compound 1 showed zero (0) silver affinity. A 1:1 mol/mol mixture of compound 2 and silver ions studied by solution 1H NMR revealed a novel “Molecular Roulette” type of motion.
Assessment of the Contribution of Road Runoffs to Surface Water Pollution in the New Juaben Municipality, Ghana  [PDF]
Louis Korbla Doamekpor, Richmond Darko, Raphael Kwaku Klake, Victus Bobonkey Samlafo, Lord Hunuor Bobobee, Cornelius Kwame Akpabli, Vincent Kodzo Nartey
Journal of Geoscience and Environment Protection (GEP) , 2016, DOI: 10.4236/gep.2016.41018
Abstract: Road runoffs were sampled from five highways and five urban roads located in the New Juaben Municipality during the late storm events in the month of November 2014 and the early storm events in January 2015. A variety of water quality parameters such as, pH, temperature, turbidity, electrical conductivity (EC), total suspended solids (TSS), total dissolved solids (TDS), aqueous concentrations of Chloride (Cl-), Phosphate (\"\"), Nitrate (\"\") and Sulphate (\"\") ions as well as the total concentrations of some selected heavy metals (Fe, Cu, Zn, Pb, Cd, Ni and Cr) were analysed for both periods. Although the results for the studied parameters, particularly the heavy metals varied for both sampling periods, the general trend indicated an increase in accumulation from November 2014 to January 2015. This was attributed to vehicular deposition as well as other natural and anthropogenic depositions on the road surfaces during the antecedent dry weather period between the two sampling months. The highest increase in pollutant loadings was associated with the heavy metals and some physico-chemical parameters such as TSS, TDS, EC and turbidity. Generally, EC, TDS, TSS and turbidity were above the permissible limits of the Environmental Protection Agency (EPA) of Ghana for both sampling periods. However, almost all the mean concentrations of heavy metals recorded for both road runoffs and the control samples were within the permissible limits of the Ghana EPA with some few exceptions.
Effects of Quarry Activities on some Selected Communities in the Lower Manya Krobo District of the Eastern Region of Ghana  [PDF]
Vincent Kodzo Nartey, Joseph Nii Nanor, Raphael Kweku Klake
Atmospheric and Climate Sciences (ACS) , 2012, DOI: 10.4236/acs.2012.23032
Abstract: Extraction of Limestone is an economically important and widespread activity in Ghana and has existed since historical times. However, in spite of its remarkable contribution towards economic development, some adverse impacts have been noticed, especially where extraction is carried out without proper planning and use of modern technology and scientific methods. We have carried out an assessment on the environmental effects of limestone quarrying on some communities in the Lower Manya Krobo District in the Eastern region of Ghana. Dust emission is one of the major effects of the practice of limestone extraction and as such, dust (PM10) sampling was conducted at the affected communities. Mean dry season results recorded in these communities stand at 125.0 μg/m3 or Bueryonye, 116.0 μg/m3 at Odugblase and 109.3 μg/m3 at Klo-Begoro. Oterkpolu community which served as the control recorded an average of 50.5 μg/m3. Average rainy season values recorded for the communities were 83.3 μg/m3 for Bueryonye, 113.1 μg/m3 at Odugblase and 74.4 μg/m3 at Klo-Begoro. The control community, Oterkpolu, had 43.3 μg/m3. These values are above the EPA, Ghana daily guideline level of 70 μg/m3 over a time-weighted average per 24 hours. Questionnaires administration and health records obtained from the health facilities in the communities revealed notable deteriorations in the health of the people as a result of the quarrying activities in the area. Notable among these is the prevalence of malaria though not related to dust emissions, it results from mosquitoes breeding in the stagnant pools of water found in pits created as a result of the mining activity. Other common health cases recorded were acute respiratory tract infection, ear and eye infections, cough and pneumonia.
Assessment of Mercury Pollution in Rivers and Streams around Artisanal Gold Mining Areas of the Birim North District of Ghana  [PDF]
Vincent K. Nartey, Raphael K. Klake, Ebenezer K. Hayford, Louis K. Doamekpor, Richard K. Appoh
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.29141
Abstract: Artisanal gold mining in local communities is on the increase. This has led to concerns about mercury pollution resulting from these mining activities. This study was conducted to assess the level of mercury pollution in rivers and streams around artisanal gold mining areas of the Birim North District of Ghana. Rivers, streams, sediments and boreholes were sampled to determine total mercury levels during the wet and dry seasons and to explore the potential impact of the mercury levels on water quality in the area. The results show that the total mercury concentrations measured upstream were significantly lower than concentrations in samples taken downstream. Also, the total mercury concentrations measured in the stream water samples in both seasons exceeded the WHO guideline limit (1.0 µg/L) for drinking water. However, one downstream total mercury concentration exceeded the guideline limit in the dry season. The total mercury concentrations in sediments upstream and downstream in both seasons exceeded the US-EPA guideline value of 0.2 mg/kg. The boreholes in the study area have total mercury concentrations exceeding the WHO guideline limit during both seasons. Total mercury concentrations in the boreholes in the wet season were lower than the dry season.
Key Labeling Technologies to Tackle Sizeable Problems in RNA Structural Biology
Kwaku T. Dayie
International Journal of Molecular Sciences , 2008, DOI: 10.3390/ijms9071214
Abstract: The ability to adopt complex three-dimensional (3D) structures that can rapidly interconvert between multiple functional states (folding and dynamics) is vital for the proper functioning of RNAs. Consequently, RNA structure and dynamics necessarily determine their biological function. In the post-genomic era, it is clear that RNAs comprise a larger proportion (>50%) of the transcribed genome compared to proteins (≤ 2%). Yet the determination of the 3D structures of RNAs lags considerably behind those of proteins and to date there are even fewer investigations of dynamics in RNAs compared to proteins. Site specific incorporation of various structural and dynamic probes into nucleic acids would likely transform RNA structural biology. Therefore, various methods for introducing probes for structural, functional, and biotechnological applications are critically assessed here. These probes include stable isotopes such as 2H, 13C, 15N, and 19F. Incorporation of these probes using improved RNA ligation strategies promises to change the landscape of structural biology of supramacromolecules probed by biophysical tools such as nuclear magnetic resonance (NMR) spectroscopy, X-ray crystallography and Raman spectroscopy. Finally, some of the structural and dynamic problems that can be addressed using these technological advances are outlined.
Key Labeling Technologies to Tackle Sizeable Problems in RNA Structural Biology
Kwaku T. Dayie
International Journal of Molecular Sciences , 2008,
Abstract: The ability to adopt complex three-dimensional (3D) structures that can rapidly interconvert between multiple functional states (folding and dynamics) is vital for the proper functioning of RNAs. Consequently, RNA structure and dynamics necessarily determine their biological function. In the post-genomic era, it is clear that RNAs comprise a larger proportion (>50%) of the transcribed genome compared to proteins ( ¢ ‰ ¤ 2%). Yet the determination of the 3D structures of RNAs lags considerably behind those of proteins and to date there are even fewer investigations of dynamics in RNAs compared to proteins. Site specific incorporation of various structural and dynamic probes into nucleic acids would likely transform RNA structural biology. Therefore, various methods for introducing probes for structural, functional, and biotechnological applications are critically assessed here. These probes include stable isotopes such as 2H, 13C, 15N, and 19F. Incorporation of these probes using improved RNA ligation strategies promises to change the landscape of structural biology of supramacromolecules probed by biophysical tools such as nuclear magnetic resonance (NMR) spectroscopy, X-ray crystallography and Raman spectroscopy. Finally, some of the structural and dynamic problems that can be addressed using these technological advances are outlined.
Crafting Strategy That Measures Up
Kwaku Ahenkora,Ofosuhene Peasah
International Journal of Business and Management , 2011, DOI: 10.5539/ijbm.v6n10p278
Abstract: The strategic management literature is replete with seldom-tested directives on crafting strategy. This study used corporate historical analysis of Proctor and Gamble (P&G) to examine the extent to which the company’s near decade (2000-2009) strategies reflect the theoretical rationale of Thompson and Strickland’s popular textbook’s ‘10 Commandments’ of crafting strategy. P&G attributed the decade’s performance to the choices it made by designing the company to lead with clear strategies, core strengths needed to win in the industry, rigorous cash and cost discipline and diversity of leadership. P&G’s strategy partially reflected the predominantly economic themes of the 10 commandments. The company also leveraged dynamic capabilities and harnessed alliance competence, concepts embedded in the evolution of strategic management.
Internet Banking Security Strategy: Securing Customer Trust
Frimpong Twum,Kwaku Ahenkora
Journal of Management and Strategy , 2012, DOI: 10.5430/jms.v3n4p78
Abstract: Internet banking strategies should enhance customers’ online experiences which are affected by trust and security issues. This study provides perspectives of users and nonusers on internet banking security with a view to understanding trust and security factors in relation to adoption and continuous usage. Perception of internet banking security influenced usage intentions. Nonusers viewed internet banking to be insecure but users perceived it to be secure with perceived ease of use influencing continuous usage. Perception of internet banking security was positively influenced by trust in the internet banking system, trust of the provider, threat awareness, availability of information and education but showed a negative relationship with age. The study suggests that internet banking security strategy may consider the generation gap in adoption and should continuously aim at securing customers’ trust of the providers’ online brand’s security, including the provision of security information and education.
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