The overall objective of this paper is to evaluate the potential of laser spectrochemical analytical techniques as rapid, cost-effective, and accurate techniques to detect the onset of spoilage in ...fresh chicken breast fillets in three consecutive days directly following slaughter day. Samples were periodically examined via laser-induced breakdown spectroscopy (LIBS) and laser-induced fluorescence (LIF). In the case of LIBS, the cyanide (CN) and carbon (C
2
) molecular spectral emission bands in the LIBS spectra of meat have been taken as indicators of protein content in the chicken breast samples. The ratio of ionic to atomic spectral lines of both magnesium and iron is found to be proportional to the chicken meat tenderness which decreases with storage time. LIF has been also exploited as a simple and fast technique for white meat spoilage detection. There was a clear inverse proportionality between the intensity of the samples’ fluorescence band and the storage period. The obtained spectrochemical results have been validated by measuring the total proteins in the investigated samples using a conventional meat analyzer. This work demonstrates the feasibility of adopting LIBS and LIF techniques in characterization of both fresh and spoiled chicken meat samples.
This paper describes the analysis and design of an LCL resonant power supply for ozone generation. The main advantage of the proposed topology is the absence of high-voltage transformer; the high ...voltage gain is achievable by means of double-resonance phenomena. Furthermore, the bandwidth is wider than the ordinary LC and its phase difference is constant over specific frequency range; as a result, an open-loop operation can be implemented. The complete analysis and design procedure of the power supply is presented. The design procedure is verified by implementing the power supply to drive a dielectric barrier discharge prototype ozone chamber. The hardware results are found to be in close agreement with simulation and thus justify the validity of the design procedures. The proposed circuit is suitable for portable ozone power supply fed by low-voltage source such as battery or photovoltaic module.
In this work, results are presented on the application of standard LIBS and Nanoparticle-Enhanced LIBS (NELIBS) to the classification of rocks (igneous and sedimentary). The classification of the ...spectra obtained with the two methods was performed using Principal Component Analysis (PCA) and Graph Theory method. The results obtained confirmed the advantages of the LIBS technique in geological applications, showing that excellent classification of the rocks analyzed (more than 99% of the spectra correctly classified) can be obtained using standard LIBS coupled to Graph Theory analysis, while NELIBS spectra, analyzed with the same technique, provide acceptable results, but with 10% of the spectra not classified. These findings are particularly interesting given the application of the LIBS technique in investigating natural samples having porous and/or rough surfaces.
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•A number of sedimentary and igneous rock samples were analyzed via LIBS and NELIBS.•The NELBS spectral lines intensity showed pronounced improvement compared to LIBS.•Surface hardness of the samples was compared from the spectroscopic data.•PCA and the graph theory techniques were used to characterize the rock samples.•LIBS with graph theory revealed better classification results than NELIBS for rocks.
This study focuses on the use of laser-induced breakdown spectroscopy (LIBS) for the evaluation of the nutrients in maternal milk and some commercially available infant formulas. The results of such ...evaluation are vital for adequate and healthy feeding for babies during lactation period. Laser-induced breakdown spectroscopy offers special advantages in comparison to the other conventional analytical techniques. Specifically, LIBS is a straightforward technique that can be used in situ to provide qualitative analytical information in few minutes for the samples under investigation without preparation processes. The samples studied in the current work were maternal milk samples collected during the first 3 months of lactation (not colostrum milk) and samples from six different types of commercially available infant formulas. The samples' elemental composition has been compared with respect to the relative abundance of the elements of nutrition importance, namely Mg, Ca, Na, and Fe using their spectral emission lines in the relevant LIBS spectra. In addition, CN and C2 molecular emission bands in the same spectra have been studied as indicators of proteins content in the samples. The obtained analytical results demonstrate the higher elemental contents of the maternal milk compared with the commercial formulas samples. Similar results have been obtained as for the proteins content. It has been also shown that calcium and proteins have similar relative concentration trends in the studied samples. This work demonstrates the feasibility of adopting LIBS as a fast, safe, less costly technique evaluating qualitatively the nutrients content of both maternal and commercial milk samples.
•Evaluation of elements of nutrients importance in human milk and commercially available infants' milk via LIBS.•Using LIBS, it is also possible to evaluate maternal milk of mothers of different ages.•Proteins content in all investigated samples has been evaluated in view of its relation to calcium concentration.•CN and C2 molecular bands intensities have been used as indicator of the proteins concentration.
Proteins in canned tuna fish were assessed using laser-induced breakdown spectroscopy (LIBS) technique. Biosynthesized nanoparticles (BS-NPs) have been used to enhance the emission intensity of the ...spectral lines in LIBS spectra of tuna fish samples. Silver nanoparticles (Ag NPs) were biosynthesized in a simple and cheap way using potatoes (Solanum tuberosum) extract. Three cans from each of three different brands of high-, medium- and low-quality canned tuna fish were investigated. Six samples, pressed in small tablets, have been taken from each can. Half the number of samples was used for conventional LIBS measurements, while the other half was used for nano-enhanced LIBS. An enhancement of more than three times has been obtained in the spectral lines intensity of the biosynthesized nano-enhanced LIBS (BS-NELIBS) spectra. The intensities of CN and C2 molecular bands (at 388.34, and 516.52 nm respectively) in the obtained spectra are related to the proteins' content, and consequently to the quality of the different tuna fish brands. The conventionally estimated proteins' content in the three investigated brands of canned tuna validated the results obtained via BS-NELIBS. Quantitative estimation of the proteins in tuna samples was available using the correlation between the protein percentage measured conventionally and CN intensity in the relevant LIBS spectra. BS-NELIBS has been proven to be easy, fast and reliable analytical technique for the qualitative and quantitative estimation of the proteins in canned tuna fish. This method is feasibly applicable in the production monitoring of canned foods containing proteins.
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•Biosynthesized silver nanoparticles (Ag NPs) were used to enhance LIBS sensitivity.•The BS-NELIBS technique is used to assess proteins in three canned tuna fish brands.•CN and C2 bands are taken as indicators of proteins content in the tuna samples.•The BS-NELIBS results have been validated by measuring the proteins conventionally.•Correlation between protein percentage and CN intensity is used to quantify proteins.
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Colostrum is essential to guarantee normal and healthy feeding in newborn ruminants during the first hours. In the present work, Laser-Induced Breakdown Spectroscopy (LIBS), as a ...spectrochemical analytical technique, and principal component analysis (PCA) as a multivariate analysis method were used to evaluate colostrum compared to mature milk of sheep to plan the nutritional strategies for newly born lambs. Samples of colostrum have been collected from thirty-three Barki ewes. The sheep were milked every 12 h three times after birth, the fourth sample of mature milk is taken from milking in the 7th day postpartum. The spectrochemical analytical results depicted that the intensities of CN and C2 spectral bands, and C 247.86 nm atomic line (as an indicator for protein content in LIBS spectra) are higher in colostrum than that in milk. This relationship has been confirmed by measuring the total protein in the same samples conventionally. The relation between calcium and protein percentage has also been demonstrated. Moreover, it has been shown that the higher is the CN bands’ intensity the lower is the bacteria count in colostrum samples, owing to the high levels of lactoferrin with its antibacterial effect. The qualitative analysis of LIBS data using PCA led to a pronounced discrimination between colostrum and mature milk. The present study demonstrates that it is, in principle, possible to make use of the analytical and chemometric results in dairy farms to evaluate sheep colostrum to manage the nutritional strategies for the lambs.
Acinetobacter baumannii is a common cause of healthcare-associated infections (HAI) worldwide, mostly occurring in intensive care units (ICUs). Extended-spectrum beta lactamases (ESBL)-positive A. ...baumannii strains have emerged as highly resistant to most currently used antimicrobial agents, including carbapenems. The most common mechanism for carbapenem resistance in this species is β-lactamase-mediated resistance. Carbapenem-hydrolyzing class D oxacillinases are widespread among multidrug-resistant (MDR) A. baumannii strains. The present study was conducted to determine the presence and distribution of blaOXA genes among multidrug-resistant A. baumannii isolated from ICU patients and genes encoding insertion sequence (IS-1) in these isolates. Additionally, the plasmid DNA profiles of these isolates were determined. A total of 120 clinical isolates of A. baumannii from various ICU clinical specimens of four main Jordanian hospitals were collected. Bacterial isolate identification was confirmed by biochemical testing and antibiotic sensitivity was then assessed. PCR amplification and automated sequencing were carried out to detect the presence of blaOXA-51, blaOXA-23, blaOXA-24, and blaOXA-58 genes, and ISAba1 insertion sequence. Out of the 120 A. baumannii isolates, 95% of the isolates were resistant to three or more classes of the antibiotics tested and were identified as MDR. The most frequent resistance of the isolates was against piperacillin (96.7%), cephalosporins (97.5%), and β-lactam/β-lactamase inhibitor combinations antibiotics (95.8%). There were 24 (20%) ESBL-producing isolates. A co-existence of blaOXA-51 gene and ISAba1 in all the 24 ESBL-producing isolates was determined. In addition, in the 24 ESBL-producing isolates, 21 (87.5%) carried blaOXA-51 and blaOXA-23 genes, 1 (4.2%) carried blaOXA-51 and blaOXA-24, but all were negative for the blaOXA-58 gene. Plasmid DNA profile A and profile B were the most common (29%) in ESBL-positive MDR A. baumannii isolates while plasmid DNA profile A was the most common in the ESBL-negative isolates. In conclusion, there was an increase in prevalence of MDR-A. baumannii in ICU wards in Jordanian hospitals, especially those having an ESBL phenotype. Thus, identification of ESBL genes is necessary for the surveillance of their transmission in hospitals.
This paper reports on the effects of LIBS experimental conditions on the measurement of the surface hardness of calcified tissues. The technique mainly depends on a previously demonstrated ...correlation between the intensity ratio of ionic to atomic spectral lines and the hardness of the target material. Three types of calcified tissues have been examined, namely enamel of human teeth, shells, and eggshells. Laser-induced breakdown spectra were obtained under two different experimental conditions. In the first nano and picoseconds, laser pulses were used in a single-pulse arrangement, while in the second, single- and double-pulse regimes with nanosecond laser excitation were utilized. The results show that the ionic to atomic spectral line intensity ratios are higher in the case of picosecond laser pulse for both Ca and Mg spectral lines. This effect has been justified in view of the repulsive force of the laser-induced shock waves which depends clearly on the target surface hardness and on the laser irradiance. The electron densities ratio (pico/nano) is shown to be strongly depending on the laser irradiance too. In the case of calcium, single-pulse ratios are higher than the double-pulse ratios, while there is no appreciable difference between both in the case of magnesium. The results obtained herein suggest that double-pulse nanosecond arrangement and the choice of a minor element such as Mg furnishes the best experimental conditions for estimating the surface hardness via LIBS spectra. To validate this method, it has been applied on two previously measured groups of teeth enamel, the first is of ancient Egyptians, and the second from Nubians and Ugandans. The results support the usefulness of this method for similar real-life applications.
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