Abebe Belay - Academia.edu (original) (raw)
Papers by Abebe Belay
International Journal of Physical Sciences, Nov 30, 2009
The integrated absorption cross-section of caffeine in water and dichloromethane, in the wave num... more The integrated absorption cross-section of caffeine in water and dichloromethane, in the wave number regions of 20,000 -39,062 cm -1 at room temperature, were (4.44 ± 0.18) × 10 7 and (4.32 ± 0.11) × 10 7 L mol -1 cm -2 , respectively. The corresponding calculated values for oscillator strength of caffeine in water and dichloromethane were 0.19 × 0.01 and 0.18 ± 0.01, respectively. In addition, the number densities of caffeine in different coffee beans were reported using integrated absorption coefficient technique. The number density of caffeine calculated in different coffee varieties were (3.53 -4.76) × 10 -5 mol L -1 . The new applied technique has an advantage over other techniques in that it provides more information about the nature of the absorbing molecules and establishes accurate evaluation of the UV-Vis absorption intensity.
International Journal of Physical Sciences, Nov 30, 2009
The integrated absorption cross-section of caffeine in water and dichloromethane, in the wave num... more The integrated absorption cross-section of caffeine in water and dichloromethane, in the wave number regions of 20,000 -39,062 cm -1 at room temperature, were (4.44 ± 0.18) × 10 7 and (4.32 ± 0.11) × 10 7 L mol -1 cm -2 , respectively. The corresponding calculated values for oscillator strength of caffeine in water and dichloromethane were 0.19 × 0.01 and 0.18 ± 0.01, respectively. In addition, the number densities of caffeine in different coffee beans were reported using integrated absorption coefficient technique. The number density of caffeine calculated in different coffee varieties were (3.53 -4.76) × 10 -5 mol L -1 . The new applied technique has an advantage over other techniques in that it provides more information about the nature of the absorbing molecules and establishes accurate evaluation of the UV-Vis absorption intensity.
UV/Vis spectroscopy has been used to investigate the self-association of the Quinolone drugs (Nor... more UV/Vis spectroscopy has been used to investigate the self-association of the Quinolone drugs (Norfloxacin and Ciprofloxacin) in aqueous solution at room temperature (295) K. The calculated value for the dimerization constant of these drugs self-association analyzed using dimer model equation by fitting to the experimental value are 1 3 10 424 . 5 M and 1 3 10 377 . 4 M respectively. The thermodynamic parameters (Gibbs free energy, enthalpy and entropy) of dimerization reactions for the self-association of the drugs were also investigated using Vant’s Hoff equation at the temperature ranges (295-304 K). The change of enthalpy calculated for Norfloxacin and Ciprofloxacin are ) 459 . 0 35 . 5 ( and ) 25 . 0 98 . 1 ( 1 . mol kJ respectively. The values of change in enthalpy and entropy indicate that the electrostatic forces play the major role in the interaction between the molecules of the drugs. Finally the results of the study are useful in order to design the advan...
Journal of Lasers, Optics & Photonics, 2018
The concentration, wavelength and temperature dependent refractive index of sugar solution has be... more The concentration, wavelength and temperature dependent refractive index of sugar solution has been investigated. The refractive index of sugar solutions (5%-50%) obtained using Red Diode Laser, Green Diode Laser and He-Ne Laser light were found to be in the range of (1.3357-1.4117), (1.3467-1.4272) and (1.3380-1.4140) respectively. The refractive index has linear relationship with the concentration of sugar solution. Mathematical expressions were also derived for the wavelength dependent refractive index of sugar solution by fitting Cauchy's equation to the experimental data using non-linear curve at the minimum discrepancy. The empirical expression of temperature dependent of refractive index of the sugar solution was determined; and the result indicates that, as the temperature increases the refractive index of the solutions decrease the method was also applied to determine the sugar contents in soft drink beverages (Pepsi, Coca, 7up, Sprite, Fanta and Mirinda). The results in g/100 ml are: (10.48 ± 0.001), (10.42 ± 0.001), (10.42 ± 0.001), (6.79 ± 0.002), (7.03 ± 0.001) and (9.89 ± 0.002) respectively. The techniques are simple, fast and inexpensive.
East European journal of physics, Dec 6, 2022
Nicotinamide (NIC) is an amide-form vitamin with a carboxamide group at b positions that is invol... more Nicotinamide (NIC) is an amide-form vitamin with a carboxamide group at b positions that is involved in a variety of biological activities. The drugs contain functional groups which control the type and degree of interaction with different solvents. In this research, the ground and excited state dipole moments of nicotinamide (NIC) were estimated using solvatochromic effects and computational work. A general overview of solvent effects on the electronic absorption and fluorescence spectra of NIC is presented. In both spectra, pronounced solvatochromic effects were observed, and the shift of emission peaks was larger than the corresponding absorption spectra. The experimental ground state g and excited state e dipole moments of NIC are estimated from solvatochromic shifts of absorption and fluorescence spectra. The differences between the excited and ground state dipole moments determined by all the methods are quite similar. The HOMO-LUMO energy band gaps were calculated and found to be 5.566 eV. The excited state dipole moment is found to be higher than those of the ground state for all of the used methods, and it is attributed to the more polar excited state of NIC. Finally, the observed spectral properties, measured values of dipole moments, and electronic structures of NIC in different solvents provide important details about charge distribution and solute-solvent interactions that may be helpful in the investigation of these molecules in biological systems.
Quantum machine learning assisted lung cancer telemedicine
AIP Advances
The rapidly increasing human population, the high cost of medical equipment, and the spread of mu... more The rapidly increasing human population, the high cost of medical equipment, and the spread of multifactor diseases have transformed the entire healthcare industry into an electronic consulting, telediagnosis, delivery, and treatment model to avoid the physical personalization of patients. Despite this, we face many challenges, including low sensitivity of medical instruments, signal losses, and security of medical records. This study aims to develop a lung cancer telemedicine platform that utilizes classical and quantum computing models to classify lung cancer subtypes and stages and develop effective telemedicine techniques. By using optoplasmonic biosensors, the biosignals (that show lung cancer) were extracted and correlated with cloud datasets (containing patient information) to determine the dose of laser interstitial thermal therapy (LITT). Then, applying quantum teleportation, the biosignals and doses of LITT were teleported between two healthcare stations. From the numerica...
Ground and Excited State Dipole Moments of Metformin Hydrochloride using Solvatochromic Effects and Density Functional Theory
Journal of Fluorescence
Optoplasmonic biosensor for lung cancer telediagnosis: Design and simulation analysis
Sensors International
Journal of Nanomaterials
Photoluminescent carbon quantum dots (CQDs) were synthesized from lemon juice precursors via sing... more Photoluminescent carbon quantum dots (CQDs) were synthesized from lemon juice precursors via single-step, hydrothermal techniques under different temperatures to control the optical properties. The synthesized CQDs were characterized by PL, illuminated UV analyzer chamber, UV–vis spectroscopy, X-ray diffractometer, Fourier-transformed infrared spectrophotometry, and zeta potential techniques. The results show that the synthesized CQDs had an excellent blue–green emission extending up to the infrared region with high quantum yield (Φ) in the range of 14%–41%. The effect of reaction temperature and the aging of CQDs on the emission spectra of CQDs are also investigated. Furthermore, the adsorption effect of the synthesized CQDs was evaluated on methylene blue (MB) dyes. The result indicated the synthesized CQDs have excellent adsorbent properties with a removal efficiency of 60%–82% and an extremely fast adsorption rate of 6 × 10−2 min−1 for MB dyes.
Photophysical properties of levofloxacin and norfloxacin drugs and their fluorescence quenching mechanism with caffeine
Spectroscopy Letters
Determination the Optical Transition Probabilities and Number Densities of Ethidium Bromide (EB) in Hetero-Association by Integrated Absorption
In this research, the optical transition probabilities (molar decadeic absorption coefficient, in... more In this research, the optical transition probabilities (molar decadeic absorption coefficient, integrated absorption cross-section, transition dipole moment, oscillator strength and full width at half maxima of the spectra) and number densities of EB in hetero-association (EB-CA) were calculated by integrated absorption coefficient techniques in the wave number regions 17680-25406 cm -1 at room temperature (298 K).The optical transition probabilities of EB calculated at different pH values show linear relation (R 2 =0.99) with pH value of the medium. On the other hand, exponentially decreases in the optical transition probabilities of EB monomers in hetero-association complex (EB-CA) were observed as caffeine concentrations increase. The relative molar ratio of free and bound EB calculated by integrated absorption coefficient techniques at concentrations of EB and caffeine (50 M and 2.53 mM) are 15.46 and 84.54 %. In addition, the hetero-association of EB-CA was analyzed using mod...
International Journal of Physical Sciences, 2017
The optical transition probabilities and hetero-association of caffeine with norfloxacin were obt... more The optical transition probabilities and hetero-association of caffeine with norfloxacin were obtained using UV-Vis spectroscopy in aqueous solution at room temperature (295K). The heter-association constant of norfloxacin-caffeine complexes (6.67×10 3 M-1) was obtained using Benesi-Hildebrand approach by linear curve fitting to the experimental data. In order to characterize the binding system of the compounds, the thermodynamic parameters were investigated using Vant's Hoff equation at the temperature ranges (295 to 304K) with a change in enthalpy value (-1.277±0.103 kJ.mol-1 .K-1). The values of change in the thermodynamic parameters indicated that the electrostatic forces play the major role in the binding reaction between the molecules of norfloxacin-caffeine complexes. In addition, the optical transition probabilities of norfloxacin were also calculated in the wavenumber regions from (20000 to 40000 cm-1) by using integrated absorption coefficient techniques. This study is very important for understanding the binding reaction in biological system, nature and strength of the transition, absorption spectral interpretation, and in providing stringent test of atomic and molecular structure calculations for theoretical work of the compounds.
International Journal of Physical Sciences, 2016
The self-association, optical transition probabilities, and hetero-association with chlorogenic a... more The self-association, optical transition probabilities, and hetero-association with chlorogenic acid of nicotinamide were obtained from UV-Vis spectroscopy in aqueous solution at room temperature (293K). The dimerization constant of nicotinamide (1 4 cm by using integrated absorption coefficient techniques. Finally, the results of this study are very important for understanding the binding reaction in biological system, nature and strength of the transition in molecular interaction, absorption spectral interpretation, and in providing stringent test of atomic and molecular structure calculations in theoretical work of the compounds.
The hetero-association of caffeine with 5-caffeoylquinic acid and ethidium bromide
Journal of Biological Physics and Chemistry, 2013
-cinnamic acid with (-)quinic acid)are bioactive compounds naturally available in leaves,seeds an... more -cinnamic acid with (-)quinic acid)are bioactive compounds naturally available in leaves,seeds and fruits of plant species [1]. The most commonsources of CA are coffee beans, coca beans, cola nutsand tea leaves [2]; CQA is found in potatoes, coffeebeans, tobacco and wine [3]. The molecules of CA caninteract with each other in aqueous media and theseassociations have reported using various techniques suchas UV–vis spectrophotometry, FT-IR and NMR [4–10].The molecules of CA are aggregated in aqueous solutionby plane-to-plane stacking [11–13] and these kind ofstacking interactions are usually important in connexionwith the pharmacological action of caffeine and theinteraction between CA and nucleic acids. CA alsointeracts with polyphenols [14] and aromatic hydroxyacids such as methyl gallate, 3-nitrobenzic acid [15], 5-chlorosalicylic acid [16], pyrogallol [17], catechins [18],theaflavin [19], gallic acid and quercitin [20].The equilibrium constant for the complexation of CAwith the major polyphenolic constitutents of green coffeebeans were initially determined in aqueous solution by thespectrophotometry [21]. By a similar method otherresearchers also reported the complexation of CA and otherpurine alkaloids with chlorogenate compounds [22]. Yetothers described the 1:1 caffeine:chlorogenate complexationusing nuclear magnetic resonance (NMR) [23],determining the association constant and identifying thechlorogenate ion moiety involved in the complexformation. Further, they also proposed that the plane ofthe caffeine molecule is parallel to the plane of thearomatic ring of the caffeoyl ester group and that the five-and six-membered rings of the nitrogen heterocycle areequally involved in the complex formation. Apart from theabove-mentioned studies, recently there were reports onthe complexation of caffeine with 3-caffeoylquinic acidand the caffeine–chlorogenate complex in a freshlyprepared coffee brew by high resolution
Measurement of caffeine in coffee beans with UV/vis spectrometer
Food Chemistry, 2008
... Belay a , Corresponding Author Contact Information , E-mail The Corresponding Author , Kassah... more ... Belay a , Corresponding Author Contact Information , E-mail The Corresponding Author , Kassahun Ture a , Mesfin Redi b and Araya Asfaw a. ... A caffeine sample was obtained from Evan, England and Arabic coffee beans were provided by Ethiopia coffee and tea quality and ...
Nano Biomedicine and Engineering
Rare earth elements doped with zinc oxide nanoparticles (ZnO-NPs) have gathered a remarkable inte... more Rare earth elements doped with zinc oxide nanoparticles (ZnO-NPs) have gathered a remarkable interest for their potential credence due to their high luminescent intensities. In this research, europium ion (Eu 3+) doped and undoped zinc oxide nanoparticles (Eu 1-x Zn x O) (x = 0.03, 0.06, 0.09) were synthesized via co-precipitation method. The effects of varying the concentration of the europium ion (Eu 3+) on the structure and optical properties were investigated. The structural and optical properties of europium ion (Eu 3+) doped and un-doped zinc oxide nanoparticles (ZnO NPs) were characterized by XRD, UV-Vis, Photoluminescence, and FT-IR Spectroscopy. The XRD results reveal the Europium ion (Eu 3+) was successfully incorporated into the zinc oxide host matrix and made highly crystalline. All the synthesized samples have a hexagonal wurtzite structure. UV-Vis absorption spectra measurements revealed increasing the dopant concentration increases the energy band compared to the undoped zinc oxide nanoparticles. Photoluminescence spectra confirmed doping europium ion (Eu 3+) predominantly enhances the visible emission with various series characteristics of blue and green emission compared to undoped zinc oxide nanoparticles (ZnO NPs) which exhibits the near band emission. Fourier Transform Infra Red (FTIR) spectral analysis indicated the presence of functional groups attached to Europium ion (Eu 3+) doped and undoped zinc oxide nanoparticles (ZnO NPs). In addition, the presence of an additional spectrum band with increasing the concentration of dopant amount demonstrates that europium ions (Eu 3+) were successfully substituted into the zinc oxide host matrix. The photocatalytic activity response is investigated using organic methylene blue (MB) as a pollutant model and dopant played the role in enhancing the photocatalytic kinetics because Eu 3+ ions act as an electron acceptor to promote charge separation and photocatalytic activity. The photocatalytic activity of europium ion (Eu 3+) doped zinc oxide nanoparticles has higher performance than undoped zinc oxide nanoparticles (ZnO-NPs) since the dopant has the potential candidate in minimizing the recombination probability which in turn improves the performance of photocatalytic activities which makes it suitable for the local environment.
Spectrophotometric Investigation of Major Bioactive Compounds of Coffee Beans
Advances in Public Health, 2015
Background.The diabetic complications are becoming common community problems. The outcomes of dia... more Background.The diabetic complications are becoming common community problems. The outcomes of diabetic complications are increased hospitalization, increased direct patient costs, and mortality. In Dessie, the prevalence of the diabetic complications is not well studied so far. Thus, the aim of this study is to assess prevalence of diabetic complications and associated factors among adult diabetic patients of Dessie Referral Hospital, Northeast Ethiopia.Methods.Cross-sectional study was conducted in the diabetic clinic of Dessie Referral Hospital from April to May 31, 2013. All diabetic patients who visited the clinic during the study period were included. Data was collected using interview guided self-administered questionnaire. Presence of complications and the type of medications the patient was on were identified through review of patient records. Data were cleaned, coded, and entered into SPSS for Windows version 17.0. Descriptive statistics and chi-square tests were carried ou...
The self-association of amoxicillin (AMX) and its hetero-association with biologically active com... more The self-association of amoxicillin (AMX) and its hetero-association with biologically active compound, chlorogenic acid (CGA) were investigated at room temperature (295°K). The dimerization constant of amoxicillin and thiamine (THIA) analyzed using the dimer model at the wavelength of 278 and 256 nm were found to be and , respectively. The hetero-association constant of amoxicillin and chlorogenic acid analyzed using Benesi-Hildebrand approach were . Thermodynamic parameters such as Gibbs free energy, enthalpy and entropy of dimerization reactions for the self-association and hetero-association of the compounds were also investigated using Vant’s Hoff equation at the temperature ranges (295 to 305°K). The change of enthalpy calculated for amoxicillin, thiamine and the complexes of amoxicillin-chlorogenic acid are 34.73±2.17, 54.1±4.585, and 6.988±0.493 at the temperature of 305°K, respectively. The values of change in enthalpy and entropy indicate that the hydrophobic interaction...
Journal of Spectroscopy
Levofloxacin (LVF) and norfloxacin (NRF) are a group of fluoroquinolone antibiotics, broad spectr... more Levofloxacin (LVF) and norfloxacin (NRF) are a group of fluoroquinolone antibiotics, broad spectrum used to treat various infections caused by many bacterial species. The drugs contain functional groups which control the type and degree of interaction with different solvents. In this research, the ground and excited state dipole moments of LVF and NRF drugs were estimated using solvatochromic effects and computational work. The dipole moments were estimated from absorption and emission spectra in polar and nonpolar solvents using Bakhshiev’s, Kawski–Chamma–Viallet, Lippert–Mataga, and Reichardt models. The results indicated the emission spectra are more strongly affected by solvent polarity than the absorption spectra. The calculated excited state dipole moment is larger than that of the ground state, indicating that the probe compounds are significantly more polarized in the excited state than in the ground state. From computational work, the HOMO-LUMO energy band gap, the dipole m...
International Journal of Physical Sciences, Nov 30, 2009
The integrated absorption cross-section of caffeine in water and dichloromethane, in the wave num... more The integrated absorption cross-section of caffeine in water and dichloromethane, in the wave number regions of 20,000 -39,062 cm -1 at room temperature, were (4.44 ± 0.18) × 10 7 and (4.32 ± 0.11) × 10 7 L mol -1 cm -2 , respectively. The corresponding calculated values for oscillator strength of caffeine in water and dichloromethane were 0.19 × 0.01 and 0.18 ± 0.01, respectively. In addition, the number densities of caffeine in different coffee beans were reported using integrated absorption coefficient technique. The number density of caffeine calculated in different coffee varieties were (3.53 -4.76) × 10 -5 mol L -1 . The new applied technique has an advantage over other techniques in that it provides more information about the nature of the absorbing molecules and establishes accurate evaluation of the UV-Vis absorption intensity.
International Journal of Physical Sciences, Nov 30, 2009
The integrated absorption cross-section of caffeine in water and dichloromethane, in the wave num... more The integrated absorption cross-section of caffeine in water and dichloromethane, in the wave number regions of 20,000 -39,062 cm -1 at room temperature, were (4.44 ± 0.18) × 10 7 and (4.32 ± 0.11) × 10 7 L mol -1 cm -2 , respectively. The corresponding calculated values for oscillator strength of caffeine in water and dichloromethane were 0.19 × 0.01 and 0.18 ± 0.01, respectively. In addition, the number densities of caffeine in different coffee beans were reported using integrated absorption coefficient technique. The number density of caffeine calculated in different coffee varieties were (3.53 -4.76) × 10 -5 mol L -1 . The new applied technique has an advantage over other techniques in that it provides more information about the nature of the absorbing molecules and establishes accurate evaluation of the UV-Vis absorption intensity.
UV/Vis spectroscopy has been used to investigate the self-association of the Quinolone drugs (Nor... more UV/Vis spectroscopy has been used to investigate the self-association of the Quinolone drugs (Norfloxacin and Ciprofloxacin) in aqueous solution at room temperature (295) K. The calculated value for the dimerization constant of these drugs self-association analyzed using dimer model equation by fitting to the experimental value are 1 3 10 424 . 5 M and 1 3 10 377 . 4 M respectively. The thermodynamic parameters (Gibbs free energy, enthalpy and entropy) of dimerization reactions for the self-association of the drugs were also investigated using Vant’s Hoff equation at the temperature ranges (295-304 K). The change of enthalpy calculated for Norfloxacin and Ciprofloxacin are ) 459 . 0 35 . 5 ( and ) 25 . 0 98 . 1 ( 1 . mol kJ respectively. The values of change in enthalpy and entropy indicate that the electrostatic forces play the major role in the interaction between the molecules of the drugs. Finally the results of the study are useful in order to design the advan...
Journal of Lasers, Optics & Photonics, 2018
The concentration, wavelength and temperature dependent refractive index of sugar solution has be... more The concentration, wavelength and temperature dependent refractive index of sugar solution has been investigated. The refractive index of sugar solutions (5%-50%) obtained using Red Diode Laser, Green Diode Laser and He-Ne Laser light were found to be in the range of (1.3357-1.4117), (1.3467-1.4272) and (1.3380-1.4140) respectively. The refractive index has linear relationship with the concentration of sugar solution. Mathematical expressions were also derived for the wavelength dependent refractive index of sugar solution by fitting Cauchy's equation to the experimental data using non-linear curve at the minimum discrepancy. The empirical expression of temperature dependent of refractive index of the sugar solution was determined; and the result indicates that, as the temperature increases the refractive index of the solutions decrease the method was also applied to determine the sugar contents in soft drink beverages (Pepsi, Coca, 7up, Sprite, Fanta and Mirinda). The results in g/100 ml are: (10.48 ± 0.001), (10.42 ± 0.001), (10.42 ± 0.001), (6.79 ± 0.002), (7.03 ± 0.001) and (9.89 ± 0.002) respectively. The techniques are simple, fast and inexpensive.
East European journal of physics, Dec 6, 2022
Nicotinamide (NIC) is an amide-form vitamin with a carboxamide group at b positions that is invol... more Nicotinamide (NIC) is an amide-form vitamin with a carboxamide group at b positions that is involved in a variety of biological activities. The drugs contain functional groups which control the type and degree of interaction with different solvents. In this research, the ground and excited state dipole moments of nicotinamide (NIC) were estimated using solvatochromic effects and computational work. A general overview of solvent effects on the electronic absorption and fluorescence spectra of NIC is presented. In both spectra, pronounced solvatochromic effects were observed, and the shift of emission peaks was larger than the corresponding absorption spectra. The experimental ground state g and excited state e dipole moments of NIC are estimated from solvatochromic shifts of absorption and fluorescence spectra. The differences between the excited and ground state dipole moments determined by all the methods are quite similar. The HOMO-LUMO energy band gaps were calculated and found to be 5.566 eV. The excited state dipole moment is found to be higher than those of the ground state for all of the used methods, and it is attributed to the more polar excited state of NIC. Finally, the observed spectral properties, measured values of dipole moments, and electronic structures of NIC in different solvents provide important details about charge distribution and solute-solvent interactions that may be helpful in the investigation of these molecules in biological systems.
Quantum machine learning assisted lung cancer telemedicine
AIP Advances
The rapidly increasing human population, the high cost of medical equipment, and the spread of mu... more The rapidly increasing human population, the high cost of medical equipment, and the spread of multifactor diseases have transformed the entire healthcare industry into an electronic consulting, telediagnosis, delivery, and treatment model to avoid the physical personalization of patients. Despite this, we face many challenges, including low sensitivity of medical instruments, signal losses, and security of medical records. This study aims to develop a lung cancer telemedicine platform that utilizes classical and quantum computing models to classify lung cancer subtypes and stages and develop effective telemedicine techniques. By using optoplasmonic biosensors, the biosignals (that show lung cancer) were extracted and correlated with cloud datasets (containing patient information) to determine the dose of laser interstitial thermal therapy (LITT). Then, applying quantum teleportation, the biosignals and doses of LITT were teleported between two healthcare stations. From the numerica...
Ground and Excited State Dipole Moments of Metformin Hydrochloride using Solvatochromic Effects and Density Functional Theory
Journal of Fluorescence
Optoplasmonic biosensor for lung cancer telediagnosis: Design and simulation analysis
Sensors International
Journal of Nanomaterials
Photoluminescent carbon quantum dots (CQDs) were synthesized from lemon juice precursors via sing... more Photoluminescent carbon quantum dots (CQDs) were synthesized from lemon juice precursors via single-step, hydrothermal techniques under different temperatures to control the optical properties. The synthesized CQDs were characterized by PL, illuminated UV analyzer chamber, UV–vis spectroscopy, X-ray diffractometer, Fourier-transformed infrared spectrophotometry, and zeta potential techniques. The results show that the synthesized CQDs had an excellent blue–green emission extending up to the infrared region with high quantum yield (Φ) in the range of 14%–41%. The effect of reaction temperature and the aging of CQDs on the emission spectra of CQDs are also investigated. Furthermore, the adsorption effect of the synthesized CQDs was evaluated on methylene blue (MB) dyes. The result indicated the synthesized CQDs have excellent adsorbent properties with a removal efficiency of 60%–82% and an extremely fast adsorption rate of 6 × 10−2 min−1 for MB dyes.
Photophysical properties of levofloxacin and norfloxacin drugs and their fluorescence quenching mechanism with caffeine
Spectroscopy Letters
Determination the Optical Transition Probabilities and Number Densities of Ethidium Bromide (EB) in Hetero-Association by Integrated Absorption
In this research, the optical transition probabilities (molar decadeic absorption coefficient, in... more In this research, the optical transition probabilities (molar decadeic absorption coefficient, integrated absorption cross-section, transition dipole moment, oscillator strength and full width at half maxima of the spectra) and number densities of EB in hetero-association (EB-CA) were calculated by integrated absorption coefficient techniques in the wave number regions 17680-25406 cm -1 at room temperature (298 K).The optical transition probabilities of EB calculated at different pH values show linear relation (R 2 =0.99) with pH value of the medium. On the other hand, exponentially decreases in the optical transition probabilities of EB monomers in hetero-association complex (EB-CA) were observed as caffeine concentrations increase. The relative molar ratio of free and bound EB calculated by integrated absorption coefficient techniques at concentrations of EB and caffeine (50 M and 2.53 mM) are 15.46 and 84.54 %. In addition, the hetero-association of EB-CA was analyzed using mod...
International Journal of Physical Sciences, 2017
The optical transition probabilities and hetero-association of caffeine with norfloxacin were obt... more The optical transition probabilities and hetero-association of caffeine with norfloxacin were obtained using UV-Vis spectroscopy in aqueous solution at room temperature (295K). The heter-association constant of norfloxacin-caffeine complexes (6.67×10 3 M-1) was obtained using Benesi-Hildebrand approach by linear curve fitting to the experimental data. In order to characterize the binding system of the compounds, the thermodynamic parameters were investigated using Vant's Hoff equation at the temperature ranges (295 to 304K) with a change in enthalpy value (-1.277±0.103 kJ.mol-1 .K-1). The values of change in the thermodynamic parameters indicated that the electrostatic forces play the major role in the binding reaction between the molecules of norfloxacin-caffeine complexes. In addition, the optical transition probabilities of norfloxacin were also calculated in the wavenumber regions from (20000 to 40000 cm-1) by using integrated absorption coefficient techniques. This study is very important for understanding the binding reaction in biological system, nature and strength of the transition, absorption spectral interpretation, and in providing stringent test of atomic and molecular structure calculations for theoretical work of the compounds.
International Journal of Physical Sciences, 2016
The self-association, optical transition probabilities, and hetero-association with chlorogenic a... more The self-association, optical transition probabilities, and hetero-association with chlorogenic acid of nicotinamide were obtained from UV-Vis spectroscopy in aqueous solution at room temperature (293K). The dimerization constant of nicotinamide (1 4 cm by using integrated absorption coefficient techniques. Finally, the results of this study are very important for understanding the binding reaction in biological system, nature and strength of the transition in molecular interaction, absorption spectral interpretation, and in providing stringent test of atomic and molecular structure calculations in theoretical work of the compounds.
The hetero-association of caffeine with 5-caffeoylquinic acid and ethidium bromide
Journal of Biological Physics and Chemistry, 2013
-cinnamic acid with (-)quinic acid)are bioactive compounds naturally available in leaves,seeds an... more -cinnamic acid with (-)quinic acid)are bioactive compounds naturally available in leaves,seeds and fruits of plant species [1]. The most commonsources of CA are coffee beans, coca beans, cola nutsand tea leaves [2]; CQA is found in potatoes, coffeebeans, tobacco and wine [3]. The molecules of CA caninteract with each other in aqueous media and theseassociations have reported using various techniques suchas UV–vis spectrophotometry, FT-IR and NMR [4–10].The molecules of CA are aggregated in aqueous solutionby plane-to-plane stacking [11–13] and these kind ofstacking interactions are usually important in connexionwith the pharmacological action of caffeine and theinteraction between CA and nucleic acids. CA alsointeracts with polyphenols [14] and aromatic hydroxyacids such as methyl gallate, 3-nitrobenzic acid [15], 5-chlorosalicylic acid [16], pyrogallol [17], catechins [18],theaflavin [19], gallic acid and quercitin [20].The equilibrium constant for the complexation of CAwith the major polyphenolic constitutents of green coffeebeans were initially determined in aqueous solution by thespectrophotometry [21]. By a similar method otherresearchers also reported the complexation of CA and otherpurine alkaloids with chlorogenate compounds [22]. Yetothers described the 1:1 caffeine:chlorogenate complexationusing nuclear magnetic resonance (NMR) [23],determining the association constant and identifying thechlorogenate ion moiety involved in the complexformation. Further, they also proposed that the plane ofthe caffeine molecule is parallel to the plane of thearomatic ring of the caffeoyl ester group and that the five-and six-membered rings of the nitrogen heterocycle areequally involved in the complex formation. Apart from theabove-mentioned studies, recently there were reports onthe complexation of caffeine with 3-caffeoylquinic acidand the caffeine–chlorogenate complex in a freshlyprepared coffee brew by high resolution
Measurement of caffeine in coffee beans with UV/vis spectrometer
Food Chemistry, 2008
... Belay a , Corresponding Author Contact Information , E-mail The Corresponding Author , Kassah... more ... Belay a , Corresponding Author Contact Information , E-mail The Corresponding Author , Kassahun Ture a , Mesfin Redi b and Araya Asfaw a. ... A caffeine sample was obtained from Evan, England and Arabic coffee beans were provided by Ethiopia coffee and tea quality and ...
Nano Biomedicine and Engineering
Rare earth elements doped with zinc oxide nanoparticles (ZnO-NPs) have gathered a remarkable inte... more Rare earth elements doped with zinc oxide nanoparticles (ZnO-NPs) have gathered a remarkable interest for their potential credence due to their high luminescent intensities. In this research, europium ion (Eu 3+) doped and undoped zinc oxide nanoparticles (Eu 1-x Zn x O) (x = 0.03, 0.06, 0.09) were synthesized via co-precipitation method. The effects of varying the concentration of the europium ion (Eu 3+) on the structure and optical properties were investigated. The structural and optical properties of europium ion (Eu 3+) doped and un-doped zinc oxide nanoparticles (ZnO NPs) were characterized by XRD, UV-Vis, Photoluminescence, and FT-IR Spectroscopy. The XRD results reveal the Europium ion (Eu 3+) was successfully incorporated into the zinc oxide host matrix and made highly crystalline. All the synthesized samples have a hexagonal wurtzite structure. UV-Vis absorption spectra measurements revealed increasing the dopant concentration increases the energy band compared to the undoped zinc oxide nanoparticles. Photoluminescence spectra confirmed doping europium ion (Eu 3+) predominantly enhances the visible emission with various series characteristics of blue and green emission compared to undoped zinc oxide nanoparticles (ZnO NPs) which exhibits the near band emission. Fourier Transform Infra Red (FTIR) spectral analysis indicated the presence of functional groups attached to Europium ion (Eu 3+) doped and undoped zinc oxide nanoparticles (ZnO NPs). In addition, the presence of an additional spectrum band with increasing the concentration of dopant amount demonstrates that europium ions (Eu 3+) were successfully substituted into the zinc oxide host matrix. The photocatalytic activity response is investigated using organic methylene blue (MB) as a pollutant model and dopant played the role in enhancing the photocatalytic kinetics because Eu 3+ ions act as an electron acceptor to promote charge separation and photocatalytic activity. The photocatalytic activity of europium ion (Eu 3+) doped zinc oxide nanoparticles has higher performance than undoped zinc oxide nanoparticles (ZnO-NPs) since the dopant has the potential candidate in minimizing the recombination probability which in turn improves the performance of photocatalytic activities which makes it suitable for the local environment.
Spectrophotometric Investigation of Major Bioactive Compounds of Coffee Beans
Advances in Public Health, 2015
Background.The diabetic complications are becoming common community problems. The outcomes of dia... more Background.The diabetic complications are becoming common community problems. The outcomes of diabetic complications are increased hospitalization, increased direct patient costs, and mortality. In Dessie, the prevalence of the diabetic complications is not well studied so far. Thus, the aim of this study is to assess prevalence of diabetic complications and associated factors among adult diabetic patients of Dessie Referral Hospital, Northeast Ethiopia.Methods.Cross-sectional study was conducted in the diabetic clinic of Dessie Referral Hospital from April to May 31, 2013. All diabetic patients who visited the clinic during the study period were included. Data was collected using interview guided self-administered questionnaire. Presence of complications and the type of medications the patient was on were identified through review of patient records. Data were cleaned, coded, and entered into SPSS for Windows version 17.0. Descriptive statistics and chi-square tests were carried ou...
The self-association of amoxicillin (AMX) and its hetero-association with biologically active com... more The self-association of amoxicillin (AMX) and its hetero-association with biologically active compound, chlorogenic acid (CGA) were investigated at room temperature (295°K). The dimerization constant of amoxicillin and thiamine (THIA) analyzed using the dimer model at the wavelength of 278 and 256 nm were found to be and , respectively. The hetero-association constant of amoxicillin and chlorogenic acid analyzed using Benesi-Hildebrand approach were . Thermodynamic parameters such as Gibbs free energy, enthalpy and entropy of dimerization reactions for the self-association and hetero-association of the compounds were also investigated using Vant’s Hoff equation at the temperature ranges (295 to 305°K). The change of enthalpy calculated for amoxicillin, thiamine and the complexes of amoxicillin-chlorogenic acid are 34.73±2.17, 54.1±4.585, and 6.988±0.493 at the temperature of 305°K, respectively. The values of change in enthalpy and entropy indicate that the hydrophobic interaction...
Journal of Spectroscopy
Levofloxacin (LVF) and norfloxacin (NRF) are a group of fluoroquinolone antibiotics, broad spectr... more Levofloxacin (LVF) and norfloxacin (NRF) are a group of fluoroquinolone antibiotics, broad spectrum used to treat various infections caused by many bacterial species. The drugs contain functional groups which control the type and degree of interaction with different solvents. In this research, the ground and excited state dipole moments of LVF and NRF drugs were estimated using solvatochromic effects and computational work. The dipole moments were estimated from absorption and emission spectra in polar and nonpolar solvents using Bakhshiev’s, Kawski–Chamma–Viallet, Lippert–Mataga, and Reichardt models. The results indicated the emission spectra are more strongly affected by solvent polarity than the absorption spectra. The calculated excited state dipole moment is larger than that of the ground state, indicating that the probe compounds are significantly more polarized in the excited state than in the ground state. From computational work, the HOMO-LUMO energy band gap, the dipole m...