In this paper, we were able to record luminescence spectra of olive, sunflower, corn, gourd and l... more In this paper, we were able to record luminescence spectra of olive, sunflower, corn, gourd and laurel oils, chlorophyll and carotene by using an argon laser (488–514 nm) and second harmonic Nd‐YAG laser (532 nm) along with a monochromator whose spectral range is 400–900 nm. Only when the luminescence light is vertical to laser light, two new peaks 540 nm and 673 nm have been detected with the latter one is more intense. In discussing our results, we succeeded in determining which materials in olive oil are responsible for producing the luminescence spectral peak; 673 nm. The experimental data has shown that the chlorophyll is the main part of the olive components which gives the olive oil luminescence spectral peak; 673 nm. The other luminescence spectral peak; 540 nm was common to all different kinds of oil in general.
Rapid and successful clinical diagnosis and bacterial infection treatment depend on accurate iden... more Rapid and successful clinical diagnosis and bacterial infection treatment depend on accurate identification and differentiation between different pathogenic bacterial species. A lot of efforts have been made to utilize modern techniques which avoid the laborious work and time-consuming of conventional methods to fulfill this task. Among such techniques, laser-induced breakdown spectroscopy (LIBS) can tell much about bacterial identity and functionality. In the present study, a sensitivity-improved version of LIBS, i.e. nano-enhanced LIBS (NELIBS), has been used to discriminate between two different bacteria (Pseudomonas aeruginosa and Proteus mirabilis) belonging to different taxonomic orders. Biogenic silver nanoparticles (AgNPs) are sprinkled onto the samples’ surface to have better discrimination capability of the technique. The obtained spectroscopic results of the NELIBS approach revealed superior differentiation between the two bacterial species compared to the results of the ...
Optical clearing is a relatively new approach to enhancing the optical transparency of biological... more Optical clearing is a relatively new approach to enhancing the optical transparency of biological tissues by reducing their scattering properties. The optical clearing effect is achievable via various chemical, physical, and photo-thermal techniques. The present work studied optical parameters of bovine skeletal muscles under different clearing protocols: immersion optical clearing in 99% glycerol and photo-thermal optical clearing via exposure to IR laser irradiation. Moreover, the two techniques were combined with different immersion time intervals after multiple exposure periods to get optimum results. The muscle samples’ diffuse reflectance and total transmittance were measured using a single integrating sphere and introduced to the Kubleka–Munk mathematical model to determine the absorption and reduced scattering coefficients. Results revealed a 6% scattering reduction after irradiating the sample for 10 min and immersing it in glycerol for 18 min and 8% after 20 min of laser i...
Laser Induced Breakdown Spectroscopy (LIBS) is a well known spectrochemical elemental analysis te... more Laser Induced Breakdown Spectroscopy (LIBS) is a well known spectrochemical elemental analysis technique. In our investigations of the LIBS spectra it has been found that there is a remarkable correlation between the ionic to atomic spectral lines emission ratio and the surface hardness of solid targets. This phenomenon is related to the repulsive force of the laser induced shockwaves. The present study revealed a confirmation of the above mentioned correlation and the interpretation of the phenomenon in view of the laser induced shockwaves velocity has been also proved experimentally. The relation between the target surface hardness and the ionic to atomic spectral lines intensity ratio of Zr in specially prepared steel alloys treated thermally to have different surface hardness, has been estimated via LIBS. The obtained LIBS spectra have been used to obtain Iionic/Iatomic for certain spectral lines of minor elements in the investigated alloys. The obtained linear relation between the steel samples surface hardness (measured mechanically) and the spectral lines ratio confirm the same effect. The above investigations open the door for LIBS to be exploited not only as a spectrochemical analytical technique but also as an easy way to measure the surface hardness of solid targets.
Laser-induced breakdown spectroscopy (LIBS), known also as laser-induced plasma spectroscopy (LIP... more Laser-induced breakdown spectroscopy (LIBS), known also as laser-induced plasma spectroscopy (LIPS), is a well-known spectrochemical elemental analysis technique. The field of LIBS has been rapidly matured as a consequence of growing interest in real-time analysis across a broad spectrum of applied sciences and recent development of commercial LIBS analytical systems. In this brief review, we introduce the contributions of the research groups in the African continent in the field of the fundamentals and applications of LIBS. As it will be shown, the fast development of LIBS in Africa during the last decade was mainly due to the broad environmental, industrial, archaeological, and biomedical applications of this technique.
J. Anal. At. Spectrom., 2011, Advance Article DOI:10.1039/C1JA10057B (Paper) PDF Version. Influen... more J. Anal. At. Spectrom., 2011, Advance Article DOI:10.1039/C1JA10057B (Paper) PDF Version. Influence of biological degradation and environmental effects on the interpretation of archeological bone samples with laser-induced breakdown spectroscopy. ...
The purpose of this paper is to provide the reader with comparative information about two new com... more The purpose of this paper is to provide the reader with comparative information about two new commercial echelle spectrometers equipped with intensified CCD (ICCD) detectors for laser-induced breakdown spectroscopy analysis. We carried out a performance comparison between two commercial ICCD/echelle spectrometers [ESA 3000 (LLA Instruments GmbH, Berlin-Adlershof, Germany) and a Mechelle 7500 (Multichannel Instruments, Stockholm, Sweden)] for the determination of the concentrations of Be, Mg, Si, Mn, Fe, and Cu in the same Al alloy samples adopting the same experimental conditions. The results show that both systems, despite their differences in terms of resolution, have similar performance in terms of sensitivity and precision of measurements for these elements in an Al alloy matrix at least for the range of wavelength 280-400 nm studied in this work.
ABSTRACT Laser-induced Plasma spectroscopy (LIPS) is a useful method for determining the elementa... more ABSTRACT Laser-induced Plasma spectroscopy (LIPS) is a useful method for determining the elemental composition of various materials but for long time it have been mainly restricted to qualitative and quantitative analysis of samples material. Recently LIPS is applied in addition to depth-profile analysis. In this paper we were trying to investigate the differences in the depth profile, obtained adopting femtosecond LIPS, that may occur on changing the spectral lines chosen for the analysis. The used femtosecond laser has pulse duration of 130 fs, wave length of 795 nm and pulse energy 200 muJ. It was found that the differences observed were not significant as long as the spectral lines chosen are fulfilling the LIPS spectral lines conditions.
Monitoring of the spectrochemical and optical properties of biomaterials has been widely utilized... more Monitoring of the spectrochemical and optical properties of biomaterials has been widely utilized in many biomedical applications for both diagnosis and therapy.
Fish is an essential source of many nutrients necessary for human health. However, the deliberate... more Fish is an essential source of many nutrients necessary for human health. However, the deliberate mislabeling of similar fish fillet types is common in markets to make use of the relatively high price difference. This is a type of explicit food adulteration. In the present work, spectrochemical analysis and chemometric methods are adopted to disclose this type of fish species cheating. Laser-induced breakdown spectroscopy (LIBS) was utilized to differentiate between the fillets of the low-priced tilapia and the expensive Nile perch. Furthermore, the acquired spectroscopic data were analyzed statistically using principal component analysis (PCA) and artificial neural network (ANN) showing good discrimination in the PCA score plot and a 99% classification accuracy rate of the implemented ANN model. The recorded spectra of the two fish indicated that tilapia has a higher fat content than Nile perch, as evidenced by higher CN and C2 bands and an atomic line at 247.8 nm in its spectrum. ...
Fish products are essential sources of animal proteins and numerous nutrients required for health... more Fish products are essential sources of animal proteins and numerous nutrients required for healthy human nutrition worldwide. However, some types of low-priced fish may look very similar to some other expensive types, and usually, it is not easy to differentiate between them for inexperienced customers. Moreover, in some markets, adulterating such high-priced fish types through its substitution by cheaper ones or mixing with bacterially spoiled ones, mostly when sold as fish fillets, is sometimes common. Certainly, fish microbial contamination in open markets represents serious hazards for people’s public health. Accordingly, seeking easy and fast fish fraud detection methods and their microbial contamination disclosure is crucial. Currently, available techniques are costly, time-consuming, and requiring special laboratories. In the present work, laser-induced fluorescence (LIF), as a spectrochemical analytical technique and diffuse optical measurements, has been used to discriminat...
In this paper, we were able to record luminescence spectra of olive, sunflower, corn, gourd and l... more In this paper, we were able to record luminescence spectra of olive, sunflower, corn, gourd and laurel oils, chlorophyll and carotene by using an argon laser (488–514 nm) and second harmonic Nd‐YAG laser (532 nm) along with a monochromator whose spectral range is 400–900 nm. Only when the luminescence light is vertical to laser light, two new peaks 540 nm and 673 nm have been detected with the latter one is more intense. In discussing our results, we succeeded in determining which materials in olive oil are responsible for producing the luminescence spectral peak; 673 nm. The experimental data has shown that the chlorophyll is the main part of the olive components which gives the olive oil luminescence spectral peak; 673 nm. The other luminescence spectral peak; 540 nm was common to all different kinds of oil in general.
Rapid and successful clinical diagnosis and bacterial infection treatment depend on accurate iden... more Rapid and successful clinical diagnosis and bacterial infection treatment depend on accurate identification and differentiation between different pathogenic bacterial species. A lot of efforts have been made to utilize modern techniques which avoid the laborious work and time-consuming of conventional methods to fulfill this task. Among such techniques, laser-induced breakdown spectroscopy (LIBS) can tell much about bacterial identity and functionality. In the present study, a sensitivity-improved version of LIBS, i.e. nano-enhanced LIBS (NELIBS), has been used to discriminate between two different bacteria (Pseudomonas aeruginosa and Proteus mirabilis) belonging to different taxonomic orders. Biogenic silver nanoparticles (AgNPs) are sprinkled onto the samples’ surface to have better discrimination capability of the technique. The obtained spectroscopic results of the NELIBS approach revealed superior differentiation between the two bacterial species compared to the results of the ...
Optical clearing is a relatively new approach to enhancing the optical transparency of biological... more Optical clearing is a relatively new approach to enhancing the optical transparency of biological tissues by reducing their scattering properties. The optical clearing effect is achievable via various chemical, physical, and photo-thermal techniques. The present work studied optical parameters of bovine skeletal muscles under different clearing protocols: immersion optical clearing in 99% glycerol and photo-thermal optical clearing via exposure to IR laser irradiation. Moreover, the two techniques were combined with different immersion time intervals after multiple exposure periods to get optimum results. The muscle samples’ diffuse reflectance and total transmittance were measured using a single integrating sphere and introduced to the Kubleka–Munk mathematical model to determine the absorption and reduced scattering coefficients. Results revealed a 6% scattering reduction after irradiating the sample for 10 min and immersing it in glycerol for 18 min and 8% after 20 min of laser i...
Laser Induced Breakdown Spectroscopy (LIBS) is a well known spectrochemical elemental analysis te... more Laser Induced Breakdown Spectroscopy (LIBS) is a well known spectrochemical elemental analysis technique. In our investigations of the LIBS spectra it has been found that there is a remarkable correlation between the ionic to atomic spectral lines emission ratio and the surface hardness of solid targets. This phenomenon is related to the repulsive force of the laser induced shockwaves. The present study revealed a confirmation of the above mentioned correlation and the interpretation of the phenomenon in view of the laser induced shockwaves velocity has been also proved experimentally. The relation between the target surface hardness and the ionic to atomic spectral lines intensity ratio of Zr in specially prepared steel alloys treated thermally to have different surface hardness, has been estimated via LIBS. The obtained LIBS spectra have been used to obtain Iionic/Iatomic for certain spectral lines of minor elements in the investigated alloys. The obtained linear relation between the steel samples surface hardness (measured mechanically) and the spectral lines ratio confirm the same effect. The above investigations open the door for LIBS to be exploited not only as a spectrochemical analytical technique but also as an easy way to measure the surface hardness of solid targets.
Laser-induced breakdown spectroscopy (LIBS), known also as laser-induced plasma spectroscopy (LIP... more Laser-induced breakdown spectroscopy (LIBS), known also as laser-induced plasma spectroscopy (LIPS), is a well-known spectrochemical elemental analysis technique. The field of LIBS has been rapidly matured as a consequence of growing interest in real-time analysis across a broad spectrum of applied sciences and recent development of commercial LIBS analytical systems. In this brief review, we introduce the contributions of the research groups in the African continent in the field of the fundamentals and applications of LIBS. As it will be shown, the fast development of LIBS in Africa during the last decade was mainly due to the broad environmental, industrial, archaeological, and biomedical applications of this technique.
J. Anal. At. Spectrom., 2011, Advance Article DOI:10.1039/C1JA10057B (Paper) PDF Version. Influen... more J. Anal. At. Spectrom., 2011, Advance Article DOI:10.1039/C1JA10057B (Paper) PDF Version. Influence of biological degradation and environmental effects on the interpretation of archeological bone samples with laser-induced breakdown spectroscopy. ...
The purpose of this paper is to provide the reader with comparative information about two new com... more The purpose of this paper is to provide the reader with comparative information about two new commercial echelle spectrometers equipped with intensified CCD (ICCD) detectors for laser-induced breakdown spectroscopy analysis. We carried out a performance comparison between two commercial ICCD/echelle spectrometers [ESA 3000 (LLA Instruments GmbH, Berlin-Adlershof, Germany) and a Mechelle 7500 (Multichannel Instruments, Stockholm, Sweden)] for the determination of the concentrations of Be, Mg, Si, Mn, Fe, and Cu in the same Al alloy samples adopting the same experimental conditions. The results show that both systems, despite their differences in terms of resolution, have similar performance in terms of sensitivity and precision of measurements for these elements in an Al alloy matrix at least for the range of wavelength 280-400 nm studied in this work.
ABSTRACT Laser-induced Plasma spectroscopy (LIPS) is a useful method for determining the elementa... more ABSTRACT Laser-induced Plasma spectroscopy (LIPS) is a useful method for determining the elemental composition of various materials but for long time it have been mainly restricted to qualitative and quantitative analysis of samples material. Recently LIPS is applied in addition to depth-profile analysis. In this paper we were trying to investigate the differences in the depth profile, obtained adopting femtosecond LIPS, that may occur on changing the spectral lines chosen for the analysis. The used femtosecond laser has pulse duration of 130 fs, wave length of 795 nm and pulse energy 200 muJ. It was found that the differences observed were not significant as long as the spectral lines chosen are fulfilling the LIPS spectral lines conditions.
Monitoring of the spectrochemical and optical properties of biomaterials has been widely utilized... more Monitoring of the spectrochemical and optical properties of biomaterials has been widely utilized in many biomedical applications for both diagnosis and therapy.
Fish is an essential source of many nutrients necessary for human health. However, the deliberate... more Fish is an essential source of many nutrients necessary for human health. However, the deliberate mislabeling of similar fish fillet types is common in markets to make use of the relatively high price difference. This is a type of explicit food adulteration. In the present work, spectrochemical analysis and chemometric methods are adopted to disclose this type of fish species cheating. Laser-induced breakdown spectroscopy (LIBS) was utilized to differentiate between the fillets of the low-priced tilapia and the expensive Nile perch. Furthermore, the acquired spectroscopic data were analyzed statistically using principal component analysis (PCA) and artificial neural network (ANN) showing good discrimination in the PCA score plot and a 99% classification accuracy rate of the implemented ANN model. The recorded spectra of the two fish indicated that tilapia has a higher fat content than Nile perch, as evidenced by higher CN and C2 bands and an atomic line at 247.8 nm in its spectrum. ...
Fish products are essential sources of animal proteins and numerous nutrients required for health... more Fish products are essential sources of animal proteins and numerous nutrients required for healthy human nutrition worldwide. However, some types of low-priced fish may look very similar to some other expensive types, and usually, it is not easy to differentiate between them for inexperienced customers. Moreover, in some markets, adulterating such high-priced fish types through its substitution by cheaper ones or mixing with bacterially spoiled ones, mostly when sold as fish fillets, is sometimes common. Certainly, fish microbial contamination in open markets represents serious hazards for people’s public health. Accordingly, seeking easy and fast fish fraud detection methods and their microbial contamination disclosure is crucial. Currently, available techniques are costly, time-consuming, and requiring special laboratories. In the present work, laser-induced fluorescence (LIF), as a spectrochemical analytical technique and diffuse optical measurements, has been used to discriminat...
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Papers by Mohamed Abdel Harith