Assessment of the occurrence and potential risks of antibiotics and their metabolites in South Florida waters using liquid chromatography tandem mass spectrometry

An automated on-line SPE-LC-MS/MS method was developed for the quantitation of multiple classes of antibiotics in environmental waters. High sensitivity in the low ng/L range was accomplished by using large volume injections with 10-mL of sample. Positive confirmation of analytes was achieved using two selected reaction monitoring (SRM) transitions per antibiotic and quantitation was performed using an internal standard approach. Samples were extracted using online solid phase extraction, then using column switching technique; extracted samples were immediately passed through liquid chromatography and analyzed by tandem mass spectrometry. The total run time per each sample was 20 min. The statistically calculated method detection limits for various environmental samples were between 1.2 and 63 ng/L. Furthermore, the method was validated in terms of precision, accuracy and linearity. ^ The developed analytical methodology was used to measure the occurrence of antibiotics in reclaimed waters (n=56), surface waters (n=53), ground waters (n=8) and drinking waters (n=54) collected from different parts of South Florida. In reclaimed waters, the most frequently detected antibiotics were nalidixic acid, erythromycin, clarithromycin, azithromycin trimethoprim, sulfamethoxazole and ofloxacin (19.3-604.9 ng/L). Detection of antibiotics in reclaimed waters indicates that they can't be completely removed by conventional wastewater treatment process. Furthermore, the average mass loads of antibiotics released into the local environment through reclaimed water were estimated as 0.248 Kg/day. Among the surface waters samples, Miami River (reaching up to 580 ng/L) and Black Creek canal (up to 124 ng/L) showed highest concentrations of antibiotics. No traces of antibiotics were found in ground waters. On the other hand, erythromycin (monitored as anhydro erythromycin) was detected in 82% of the drinking water samples (n.d-66 ng/L). The developed approach is suitable for both research and monitoring applications.^ Major metabolites of antibiotics in reclaimed wates were identified and quantified using high resolution benchtop Q-Exactive orbitrap mass spectrometer. A phase I metabolite of erythromycin was tentatively identified in full scan based on accurate mass measurement. Using extracted ion chromatogram (XIC), high resolution data-dependent MS/MS spectra and metabolic profiling software the metabolite was identified as desmethyl anhydro erythromycin with molecular formula C36H63NO12 and m/z 702.4423. The molar concentration of the metabolite to erythromycin was in the order of 13 %. To my knowledge, this is the first known report on this metabolite in reclaimed water. Another compound acetyl-sulfamethoxazole, a phase II metabolite of sulfamethoxazole was also identified in reclaimed water and mole fraction of the metabolite represent 36 %, of the cumulative sulfamethoxazole concentration. The results were illustrating the importance to include metabolites also in the routine analysis to obtain a mass balance for better understanding of the occurrence, fate and distribution of antibiotics in the environment. ^ Finally, all the antibiotics detected in reclaimed and surface waters were investigated to assess the potential risk to the aquatic organisms. The surface water antibiotic concentrations that represented the real time exposure conditions revealed that the macrolide antibiotics, erythromycin, clarithromycin and tylosin along with quinolone antibiotic, ciprofloxacin were suspected to induce high toxicity to aquatic biota. Preliminary results showing that, among the antibiotic groups tested, macrolides posed the highest ecological threat, and therefore, they may need to be further evaluated with, long-term exposure studies considering bioaccumulation factors and more number of species selected. Overall, the occurrence of antibiotics in aquatic environment is posing an ecological health concern.^

A heuristic algorithm to generate test program sequences for moving probe electronic test equipment

The electronics industry, is experiencing two trends one of which is the drive towards miniaturization of electronic products. The in-circuit testing predominantly used for continuity testing of printed circuit boards (PCB) can no longer meet the demands of smaller size circuits. This has lead to the development of moving probe testing equipment. Moving Probe Test opens up the opportunity to test PCBs where the test points are on a small pitch (distance between points). However, since the test uses probes that move sequentially to perform the test, the total test time is much greater than traditional in-circuit test. While significant effort has concentrated on the equipment design and development, little work has examined algorithms for efficient test sequencing. The test sequence has the greatest impact on total test time, which will determine the production cycle time of the product. Minimizing total test time is a NP-hard problem similar to the traveling salesman problem, except with two traveling salesmen that must coordinate their movements. The main goal of this thesis was to develop a heuristic algorithm to minimize the Flying Probe test time and evaluate the algorithm against a "Nearest Neighbor" algorithm. The algorithm was implemented with Visual Basic and MS Access database. The algorithm was evaluated with actual PCB test data taken from Industry. A statistical analysis with 95% C.C. was performed to test the hypothesis that the proposed algorithm finds a sequence which has a total test time less than the total test time found by the "Nearest Neighbor" approach. Findings demonstrated that the proposed heuristic algorithm reduces the total test time of the test and, therefore, production cycle time can be reduced through proper sequencing.

Desenvolvimento de métodos para quantificação de benzilpenicilina em medicamentos veterinários e seus resíduos em leite bovino e caprino por UFLC-DAD

The Benzylpenicillin (PENG) have been as the active ingredient in veterinary medicinal products, to increase productivity, due to its therapeutic properties. However, one of unfortunate quality and used indiscriminately, resulting in residues in foods exposed to human consumption, especially in milk that is essential to the diet of children and the ageing. Thus, it is indispensable to develop new methods able to detect this waste food, at levels that are toxic to human health, in order to contribute to the food security of consumers and collaborate with regulatory agencies in an efficient inspection. In this work, were developed methods for the quality control of veterinary drugs based on Benzylpenicillin (PENG) that are used in livestock production. Additionally, were validated methodologies for identifying and quantifying the antibiotic residues in milk bovine and caprine. For this, the analytical control was performed two steps. At first, the groups of samples of medicinal products I, II, III, IV and V, individually, were characterized by medium infrared spectroscopy (4000 – 600 cm-1). Besides, 37 samples, distributed in these groups, were analyzed by spectroscopy in the ultraviolet and near infrared region (UV VIS NIR) and Ultra Fast Liquid Chromatograph coupled to linear arrangement photodiodes (UFLC-DAD). The results of the characterization indicated similarities, between PENG and reference standard samples, primarily in regions of 1818 to 1724 cm-1 of ν C=O that shows primary amides features of PENG. The method by UFLC-DAD presented R on 0.9991. LOD of 7.384 × 10-4 μg mL-1. LOQ of 2.049 × 10-3 μg mL-1. The analysis shows that 62.16% the samples presented purity ≥ 81.21%. The method by spectroscopy in the UV VIS NIR presented medium error ≤ 8 – 12% between the reference and experimental criteria, indicating is a secure choice for rapid determination of PENG. In the second stage, was acquiring a method for the extraction and isolation of PENG by the addition of buffer McIlvaine, used for precipitation of proteins total, at pH 4.0. The results showed excellent recovery values PENG, being close to 92.05% of samples of bovine milk (method 1). While samples of milk goats (method 2) the recovery of PENG were 95.83%. The methods for UFLC-DAD have been validated in accordance with the maximum residue limit (LMR) of 4 μg Kg-1 standardized by CAC/GL16. Validation of the method 1 indicated R by 0.9975. LOD of 7.246 × 10-4 μg mL-1. LOQ de 2.196 × 10-3 μg mL-1. The application of the method 1 showed that 12% the samples presented concentration of residues of PENG > LMR. The method 2 indicated R by 0.9995. LOD 8.251 × 10-4 μg mL-1. LOQ de 2.5270 × 10-3 μg mL-1. The application of the method showed that 15% of the samples were above the tolerable. The comparative analysis between the methods pointed better validation for LCP samples, because the reduction of the matrix effect, on this account the tcalculs < ttable, caused by the increase of recovery of the PENG. In this mode, all the operations developed to deliver simplicity, speed, selectivity, reduced analysis time and reagent use and toxic solvents, particularly if compared to the established methodologies.

Desenvolvimento de métodos para quantificação de benzilpenicilina em medicamentos veterinários e seus resíduos em leite bovino e caprino por UFLC-DAD

The Benzylpenicillin (PENG) have been as the active ingredient in veterinary medicinal products, to increase productivity, due to its therapeutic properties. However, one of unfortunate quality and used indiscriminately, resulting in residues in foods exposed to human consumption, especially in milk that is essential to the diet of children and the ageing. Thus, it is indispensable to develop new methods able to detect this waste food, at levels that are toxic to human health, in order to contribute to the food security of consumers and collaborate with regulatory agencies in an efficient inspection. In this work, were developed methods for the quality control of veterinary drugs based on Benzylpenicillin (PENG) that are used in livestock production. Additionally, were validated methodologies for identifying and quantifying the antibiotic residues in milk bovine and caprine. For this, the analytical control was performed two steps. At first, the groups of samples of medicinal products I, II, III, IV and V, individually, were characterized by medium infrared spectroscopy (4000 – 600 cm-1). Besides, 37 samples, distributed in these groups, were analyzed by spectroscopy in the ultraviolet and near infrared region (UV VIS NIR) and Ultra Fast Liquid Chromatograph coupled to linear arrangement photodiodes (UFLC-DAD). The results of the characterization indicated similarities, between PENG and reference standard samples, primarily in regions of 1818 to 1724 cm-1 of ν C=O that shows primary amides features of PENG. The method by UFLC-DAD presented R on 0.9991. LOD of 7.384 × 10-4 μg mL-1. LOQ of 2.049 × 10-3 μg mL-1. The analysis shows that 62.16% the samples presented purity ≥ 81.21%. The method by spectroscopy in the UV VIS NIR presented medium error ≤ 8 – 12% between the reference and experimental criteria, indicating is a secure choice for rapid determination of PENG. In the second stage, was acquiring a method for the extraction and isolation of PENG by the addition of buffer McIlvaine, used for precipitation of proteins total, at pH 4.0. The results showed excellent recovery values PENG, being close to 92.05% of samples of bovine milk (method 1). While samples of milk goats (method 2) the recovery of PENG were 95.83%. The methods for UFLC-DAD have been validated in accordance with the maximum residue limit (LMR) of 4 μg Kg-1 standardized by CAC/GL16. Validation of the method 1 indicated R by 0.9975. LOD of 7.246 × 10-4 μg mL-1. LOQ de 2.196 × 10-3 μg mL-1. The application of the method 1 showed that 12% the samples presented concentration of residues of PENG > LMR. The method 2 indicated R by 0.9995. LOD 8.251 × 10-4 μg mL-1. LOQ de 2.5270 × 10-3 μg mL-1. The application of the method showed that 15% of the samples were above the tolerable. The comparative analysis between the methods pointed better validation for LCP samples, because the reduction of the matrix effect, on this account the tcalculs < ttable, caused by the increase of recovery of the PENG. In this mode, all the operations developed to deliver simplicity, speed, selectivity, reduced analysis time and reagent use and toxic solvents, particularly if compared to the established methodologies.

Avaliação do sono e enfermeiros nos diferentes turnos hospitalares

This study aimed to analyze the pattern characteristics of sleep and sleep quality of nurses who worked day and night shifts. This is a study with a quantitative approach, cross-sectional, descriptive. The study was conducted at the University Hospital of Rio Grande do Norte. Data were collected in full in the period from January to September 2015, through the instruments: Pittsburgh Sleep Quality Index and Sleep Diary. Subjects were interviewed according to their work shift, day or night, during the working hours of the nursing team. After being coded and tabulated, data were analyzed using SPSS version 20.0. The study was approved by the Research Ethics Committee of the Federal University of Rio Grande do Norte, in the Opinion No. 751 567. For a description of continuous variables were used position measurements (mean and median), dispersion (standard deviation) and correlation (Spearman correlation test), to a 0.05 significance level. The socio-demographic profile of the sample showed a total of n = 104 participants, distributed in: 64 on day shift and night shift 40; wherein 90.4% are female, aged between 24-45 years, corresponding to 73% of the sample. There was the presence of statistically significant differences for the variables: employment and living habits (inpatient and outpatient sector (p = 0.003), have more than one job (p = 0.002), use cordial (p = 0.021); Sleep pattern: nap time (p = 0.003), sleep latency (p = 0.013), total sleep time (p = 0.001), how it felt to wake up (p = 0.017), quality of nighttime sleep (p = 0.001) and sleep quality (p = 0.007) compared between the day shift and the night shift. It was concluded that shift work has changed the pattern and sleep quality of nurses working day and night shifts.

Avaliação do sono e enfermeiros nos diferentes turnos hospitalares

This study aimed to analyze the pattern characteristics of sleep and sleep quality of nurses who worked day and night shifts. This is a study with a quantitative approach, cross-sectional, descriptive. The study was conducted at the University Hospital of Rio Grande do Norte. Data were collected in full in the period from January to September 2015, through the instruments: Pittsburgh Sleep Quality Index and Sleep Diary. Subjects were interviewed according to their work shift, day or night, during the working hours of the nursing team. After being coded and tabulated, data were analyzed using SPSS version 20.0. The study was approved by the Research Ethics Committee of the Federal University of Rio Grande do Norte, in the Opinion No. 751 567. For a description of continuous variables were used position measurements (mean and median), dispersion (standard deviation) and correlation (Spearman correlation test), to a 0.05 significance level. The socio-demographic profile of the sample showed a total of n = 104 participants, distributed in: 64 on day shift and night shift 40; wherein 90.4% are female, aged between 24-45 years, corresponding to 73% of the sample. There was the presence of statistically significant differences for the variables: employment and living habits (inpatient and outpatient sector (p = 0.003), have more than one job (p = 0.002), use cordial (p = 0.021); Sleep pattern: nap time (p = 0.003), sleep latency (p = 0.013), total sleep time (p = 0.001), how it felt to wake up (p = 0.017), quality of nighttime sleep (p = 0.001) and sleep quality (p = 0.007) compared between the day shift and the night shift. It was concluded that shift work has changed the pattern and sleep quality of nurses working day and night shifts.

Geological reference standards (JLK-1,JSD-1, JSD-2, JSD-3,JMS-1, JMS-2) measured by Itrax-XRF core scanner in different exposure times

X-ray fluorescence (XRF) core-scanning is a fast and nondestructive technique to assess elemental variations of unprocessed sediments. However, although the exposure time of XRF-scanning directly affects the scanning counts and total measurement time, only a few studies have considered the influence of exposure time during the scan. How to select an optimal exposure time to achieve reliable results and reduce the total measurement time is an important issue. To address this question, six geological reference materials from the Geological Survey of Japan (JLK-1, JMS-1, JMS-2, JSD-1, JSD-2, and JSD-3) were scanned by the Itrax-XRF core scanner using the Mo- and the Cr-tube with different exposure times to allow a comparison of scanning counts with absolute concentrations. The regression lines and correlation coefficients of elements that are generally used in paleoenvironmental studies were examined for the different exposure times and X-ray tubes. The results show that for those elements with relatively high concentrations or high detectability, the correlation coefficients are higher than 0.90 for all exposure times. In contrast, for the low detectability or low concentration elements, the correlation coefficients are relatively low, and improve little with increased exposure time. Therefore, we suggest that the influence of different exposure times is insignificant for the accuracy of the measurements. Thus, caution must be taken when interpreting the results of elements with low detectability, even when the exposure times are long and scanning counts are reasonably high.

Application of microarrays (phylochips) for analysis of community diversity by species identification

Abstract Molecular probe-based methods (Fluorescent in-situ hybridisation or FISH, Next Generation Sequencing or NGS) have proved successful in improving both the efficiency and accuracy of the identification of microorganisms, especially those that lack distinct morphological features, such as picoplankton. However, FISH methods have the major drawback that they can only identify one or just a few species at a time because of the reduced number of available fluorochromes that can be added to the probe. Although the length of sequence that can be obtained is continually improving, NGS still requires a great deal of handling time, its analysis time is still months and with a PCR step it will always be sensitive to natural enzyme inhibitors. With the use of DNA microarrays, it is possible to identify large numbers of taxa on a single-glass slide, the so-called phylochip, which can be semi-quantitative. This review details the major steps in probe design, design and production of a phylochip and validation of the array. Finally, major microarray studies in the phytoplankton community are reviewed to demonstrate the scope of the method.

Application of microarrays (phylochips) for analysis of community diversity by species identification

Abstract Molecular probe-based methods (Fluorescent in-situ hybridisation or FISH, Next Generation Sequencing or NGS) have proved successful in improving both the efficiency and accuracy of the identification of microorganisms, especially those that lack distinct morphological features, such as picoplankton. However, FISH methods have the major drawback that they can only identify one or just a few species at a time because of the reduced number of available fluorochromes that can be added to the probe. Although the length of sequence that can be obtained is continually improving, NGS still requires a great deal of handling time, its analysis time is still months and with a PCR step it will always be sensitive to natural enzyme inhibitors. With the use of DNA microarrays, it is possible to identify large numbers of taxa on a single-glass slide, the so-called phylochip, which can be semi-quantitative. This review details the major steps in probe design, design and production of a phylochip and validation of the array. Finally, major microarray studies in the phytoplankton community are reviewed to demonstrate the scope of the method.