Rapid analysis of multiclass antibiotic residues and some of their metabolites in hospital, urban wastewater and river water by ultra-highperformance liquid chromatography coupled to quadrupole-linear ion trap tandem mass spectrometry

The present work describes the development of a fast and robust analytical method for the determination of 53 antibiotic residues, covering various chemical groups and some of their metabolites, in environmental matrices that are considered important sources of antibiotic pollution, namely hospital and urban wastewaters, as well as in river waters. The method is based on automated off-line solid phase extraction (SPE) followed by ultra-high-performance liquid chromatography coupled to quadrupole linear ion trap tandem mass spectrometry (UHPLC–QqLIT). For unequivocal identification and confirmation, and in order to fulfill EU guidelines, two selected reaction monitoring (SRM) transitions per compound are monitored (the most intense one is used for quantification and the second one for confirmation). Quantification of target antibiotics is performed by the internal standard approach, using one isotopically labeled compound for each chemical group, in order to correct matrix effects. The main advantages of the method are automation and speed-up of sample preparation, by the reduction of extraction volumes for all matrices, the fast separation of a wide spectrum of antibiotics by using ultra-high-performance liquid chromatography, its sensitivity (limits of detection in the low ng/L range) and selectivity (due to the use of tandem mass spectrometry) The inclusion of β-lactam antibiotics (penicillins and cephalosporins), which are compounds difficult to analyze in multi-residue methods due to their instability in water matrices, and some antibiotics metabolites are other important benefits of the method developed. As part of the validation procedure, the method developed was applied to the analysis of antibiotics residues in hospital, urban influent and effluent wastewaters as well as in river water samples

Extracellular Subunit Interactions Control Transitions between Functional States of Acid-sensing Ion Channel 1a.

Acid-sensing ion channels (ASICs) are neuronal, voltage-independent Na(+) channels that are transiently activated by extracellular acidification. They are involved in pain sensation, the expression of fear, and in neurodegeneration after ischemic stroke. Our study investigates the role of extracellular subunit interactions in ASIC1a function. We identified two regions involved in critical intersubunit interactions. First, formation of an engineered disulfide bond between the palm and thumb domains leads to partial channel closure. Second, linking Glu-235 of a finger loop to either one of two different residues of the knuckle of a neighboring subunit opens the channel at physiological pH or disrupts its activity. This suggests that one finger-knuckle disulfide bond (E235C/K393C) sets the channel in an open state, whereas the other (E235C/Y389C) switches the channel to a non-conducting state. Voltage-clamp fluorometry experiments indicate that both the finger loop and the knuckle move away from the β-ball residue Trp-233 during acidification and subsequent desensitization. Together, these observations reveal that ASIC1a opening is accompanied by a distance increase between adjacent thumb and palm domains as well as a movement of Glu-235 relative to the knuckle helix. Our study identifies subunit interactions in the extracellular loop and shows that dynamic changes of these interactions are critical for normal ASIC function.

LC-MS method development and comparison of sampling materials for the analysis of organic gunshot residues

This study aimed at comparing the efficiency of various sampling materials for the collection and subsequent analysis of organic gunshot residues (OGSR). To the best of our knowledge, it is the first time that sampling devices were investigated in detail for further quantitation of OGSR by LC-MS. Seven sampling materials, namely two "swab"-type and five "stub"-type collection materials, were tested. The investigation started with the development of a simple and robust LC-MS method able to separate and quantify molecules typically found in gunpowders, such as diphenylamine or ethylcentralite. The evaluation of sampling materials was then systematically carried out by first analysing blank extracts of the materials to check for potential interferences and determining matrix effects. Based on these results, the best four materials, namely cotton buds, polyester swabs, a tape from 3M and PTFE were compared in terms of collection efficiency during shooting experiments using a set of 9 mm Luger ammunition. It was found that the tape was capable of recovering the highest amounts of OGSR. As tape-lifting is the technique currently used in routine for inorganic GSR, OGSR analysis might be implemented without modifying IGSR sampling and analysis procedure.

Fingermark age determinations: legal considerations, review of the literature and practical propositions

The question of the age of fingermarks is often raised in investigations and trials when suspects admit that they have left their fingermarks at a crime scene but allege that the contact occurred at a different time than the crime and for legal reasons. In the first part of this review article, examples from American appellate court cases will be used to demonstrate that there is a lack of consensus among American courts regarding the admissibility and weight of testimony from expert witnesses who provide opinions about the age of fingermarks. Of course, these issues are not only encountered in America but have also been reported elsewhere, for example in Europe. The disparity in the way fingermark dating cases were managed in these examples is probably due to the fact that no methodology has been validated and accepted by the forensic science community so far. The second part of this review article summarizes the studies reported on fingermark dating in the literature and highlights the fact that most proposed methodologies still suffer from limitations preventing their use in practice. Nevertheless, several approaches based on the evolution of aging parameters detected in fingermark residue over time appear to show promise for the fingermark dating field. Based on these approaches, the definition of a formal methodological framework for fingermark dating cases is proposed in order to produce relevant temporal information. This framework identifies which type of information could and should be obtained about fingermark aging and what developments are still required to scientifically address dating issues.

Avaliação de filtros domésticos comerciais para purificação de águas e retenção de contaminantes inorgânicos

Twenty domestic commercial filters, in order to determine the percentual retention of color, turbidity, dry residue, bicarbonates, carbonates, total hardness, nitrogens, iron, chlorides, fluorides, and residual chlorine (parameters of food legislation) and sulphides in thirteen water samples proceeding from springs, wells, rivers, lakes, drinking patterns and standards, before and after purification were evaluated. The results showed that purifiers presented adequate retention for nitrates (74.8 ± 16.2 %) and residual chlorine (74.0 ± 11.2) and medium retention for sulphides (61.7 ± 11.3); while porcelain plus activated carbon filters presented adequate retention for color (90.0 ± 19.7), turbidity (76.4 ± 18.4) and iron (83.5 ± 15.1). Therefore the retention of carbonates, bicarbonates, total hardness, chlorides, dry residue, fluorides, ammonium nitrogens and nitrites was less than 10%, and the values of pH didn't show significant variation, for all the filters studied.

Aeromonas surface glucan attached throught the O-antigen ligase represents a new way to obtain UDP-Glucose

We previously reported that A. hydrophila GalU mutants were still able to produce UDP-glucose introduced as a glucose residue in their lipopolysaccharide core. In this study, we found the unique origin of this UDP-glucose from a branched α-glucan surface polysaccharide. This glucan, surface attached through the O-antigen ligase (WaaL), is common to the mesophilic Aeromonas strains tested. The Aeromonas glucan is produced by the action of the glycogen synthase (GlgA) and the UDP-Glc pyrophosphorylase (GlgC), the latter wrongly indicated as an ADP-Glc pyrophosphorylase in the Aeromonas genomes available. The Aeromonas glycogen synthase is able to react with UDP or ADP-glucose, which is not the case of E. coli glycogen synthase only reacting with ADP-glucose. The Aeromonas surface glucan has a role enhancing biofilm formation. Finally, for the first time to our knowledge, a clear preference on behalf of bacterial survival and pathogenesis is observed when choosing to produce one or other surface saccharide molecules to produce (lipopolysaccharide core or glucan).

Metsäpolttoaineiden vesitiekuljetus proomukalustolla

Metsäpolttoaineiden käyttö kasvaa lämpö- ja voimalaitoksissa ja mahdollisissa biojalostamoissa. Metsäpolttoaineilla voidaan saavuttaa päästövähennyksiä korvaamalla päästöintensiivisempiä polttoaineita. Metsäpolttoaineen kysynnän kasvu suurkäyttöpaikoilla luo uusia vaatimuksia metsäbiomassan hankintaan. Metsäpolttoaineiden vesitiekuljetuksen sisältämiä logistiikkajärjestelmiä kehittämällä toimitusvarmuutta pystytään parantamaan ja hankintaa laajentamaan kustannustehokkaasti ja ympäristöystävällisesti. Kuljetuskokeilut antoivat uutta tietoa vesitiekuljetuksen sisältämästä hankinnasta. Lastikapasiteetti nykyisen kaltaisessa Eurooppa IIa -suurproomussa vaihtelee 1200 tonnista jopa 1800 tonniin (kosteus 40 %) riippuen tiivistymisestä ja proomun modifiointiasteesta. Metsähakkeen energiatiheys oli suurproomukuljetuksissa keskimäärin 1 MWh/i-m3, joka oli 25 % parempi kuin vertailun hakerekkakuljetuksissa. Vesitiekuljetuksen kustannukset olivat kuljetuskokeiluissa lastauksineen ja purkuineen 0,02 €/MWh/km, ollen noin 20 % ketjun kokonaiskustannuksista. Simuloinnin edullisimpien vesitiekuljetusvaihtoehtojen vaihteluvälin kustannukset olivat vastaavasti 0,013 - 0,026 €/MWh/km. Lastauksen ja purun kustannus oli 0,4 - 0,6 €/MWh ja vesitiekuljetus 0,9 - 2,0 €/MWh (100 km). Ketjun kokonaiskustannukset hakkuutähdehakkeelle vaihtelivat simuloinnin edullisimpien vaihtoehtojen perusteella välillä 10,8 - 12,1 €/MWh (30 km rekka, 100 km proomu). Kuljetusketjujen simuloinnin kustannukset osoittivat proomukuljetusketjun olevan kilpailukykyinen vaihtoehto hakerekkakuljetusketjulle kalustosta ja vuosittaisista käyttötunneista riippuen kuljetusetäisyyden ylittäessä 100 km. Kustannustehokkain ratkaisu vesitiekuljetuksessa saavutettiin pienen aluksen ja suuren kokoluokan proomuyksikön kytkyeellä. Haketus kannattaa toteuttaa ennen proomukuljetuksen osuutta metsähakkeen paremman tiiviyden ja käsiteltävyyden perusteella. Logistiikkajärjestelmiä pitää kehittää tapauskohtaisesti käyttöpaikan tarpeet ja olosuhteet huomioon ottaen. Metsäpolttoaineiden vesitiekuljetuksen sisältämän logistiikan liiketoimintamallien vertailussa arvioitiin vaihtoehtoiset ulkoistetut toimintamallit paremmaksi kuin nykyinen urakointimalli. Tämä mahdollistaa paremman metsähakkeen saatavuuden ja logistiikan tehokkuuden lastausterminaaleissa. Terminaalitoiminnot ja proomukuljetukset lisäävät uusia liiketoimintamahdollisuuksia ja mahdollistavat metsäpolttoaineiden

Kierrätyspolttoaineen käyttö leijupetikattilan konseptiin

Diplomityö tehtiin Rautjärven kunnassa sijaitsevalle M-real Simpeleen tehtaan voimalaitokselle. Voimalaitoksella on leijupetikattila ja se tuottaa prosessilämmön ja höyryn kartonki- ja paperikoneelle. Vuotuinen energiantuotanto on noin 115 GWh. Diplomityön tavoitteena oli tutkia kierrätyspolttoaineen käyttöä osana voimalaitoksen polttoainekonseptista. Voimalaitoksen biokattila on leijupetikattila, jossa poltetaan tehtaalta tulevaa kuorta ja lietettä sekä tehtaan ulkopuolisia puuperäisiä biopolttoaineita ja turvetta. Yksi työn päätavoitteista oli laatia voimassa olevan ympäristöluvan muutoshakemus, jotta kierrätyspolttoaineen käytölle saataisiin lupa. Suurten polttolaitosten päästöjen tarkkailu- ja raportointivaatimukset ovat uudistuneet viime vuosina paljon. Suurimpia muutosten aiheuttajia ovat Valtioneuvoston asetukset 1017/2002 ja 362/2003. Tässä työssä kuvataan uusien asetusten tuomia vaatimuksia itse kattilalle ja polttoaineen syötölle, jatkuvatoimisille mittalaitteille ja muille suoritettaville mittauksille. Uutena asiana on myös ilmapäästöjen seurantamittaukset ja -tapa, jolla tulokset ilmoitetaan. Mahdollisimman pieniin leijupetikattilamuutoksiin uskotaan pääsevän korvaamalla kierrätyspolttoaine REF1:llä 5 – 10 % turpeesta tai puupolttoaineista.

Experimental Identification of Actinobacillus pleuropneumoniae Strains L20 and JL03 Heptosyltransferases, Evidence for a New Heptosyltransferase Signature Sequence.

We experimentally identified the activities of six predicted heptosyltransferases in Actinobacillus pleuropneumoniae genome serotype 5b strain L20 and serotype 3 strain JL03. The initial identification was based on a bioinformatic analysis of the amino acid similarity between these putative heptosyltrasferases with others of known function from enteric bacteria and Aeromonas. The putative functions of all the Actinobacillus pleuropneumoniae heptosyltrasferases were determined by using surrogate LPS acceptor molecules from well-defined A. hydrophyla AH-3 and A. salmonicida A450 mutants. Our results show that heptosyltransferases APL_0981 and APJL_1001 are responsible for the transfer of the terminal outer core D-glycero-D-manno-heptose (D,D-Hep) residue although they are not currently included in the CAZY glycosyltransferase 9 family. The WahF heptosyltransferase group signature sequence [S(T/S)(GA)XXH] differs from the heptosyltransferases consensus signature sequence [D(TS)(GA)XXH], because of the substitution of D(261) for S(261), being unique.

Statistical Methods for Conservation and Alignment Quality in Proteins

Construction of multiple sequence alignments is a fundamental task in Bioinformatics. Multiple sequence alignments are used as a prerequisite in many Bioinformatics methods, and subsequently the quality of such methods can be critically dependent on the quality of the alignment. However, automatic construction of a multiple sequence alignment for a set of remotely related sequences does not always provide biologically relevant alignments.Therefore, there is a need for an objective approach for evaluating the quality of automatically aligned sequences. The profile hidden Markov model is a powerful approach in comparative genomics. In the profile hidden Markov model, the symbol probabilities are estimated at each conserved alignment position. This can increase the dimension of parameter space and cause an overfitting problem. These two research problems are both related to conservation. We have developed statistical measures for quantifying the conservation of multiple sequence alignments. Two types of methods are considered, those identifying conserved residues in an alignment position, and those calculating positional conservation scores. The positional conservation score was exploited in a statistical prediction model for assessing the quality of multiple sequence alignments. The residue conservation score was used as part of the emission probability estimation method proposed for profile hidden Markov models. The results of the predicted alignment quality score highly correlated with the correct alignment quality scores, indicating that our method is reliable for assessing the quality of any multiple sequence alignment. The comparison of the emission probability estimation method with the maximum likelihood method showed that the number of estimated parameters in the model was dramatically decreased, while the same level of accuracy was maintained. To conclude, we have shown that conservation can be successfully used in the statistical model for alignment quality assessment and in the estimation of emission probabilities in the profile hidden Markov models.

Comparison of three analytical methods for the determination of quinolones in pig muscle samples

This work presents a comparison between three analytical methods developed for the simultaneous determination of eight quinolones regulated by the European Union (marbofloxacin, ciprofloxacin, danofloxacin, enrofloxacin, difloxacin, sarafloxacin, oxolinic acid and flumequine) in pig muscle, using liquid chromatography with fluorescence detection (LC-FD), liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The procedures involve an extraction of the quinolones from the tissues, a step for clean-up and preconcentration of the analytes by solid-phase extraction and a subsequent liquid chromatographic analysis. The limits of detection of the methods ranged from 0.1 to 2.1 ng g−1 using LC-FD, from 0.3 to 1.8 using LC-MS and from 0.2 to 0.3 using LC-MS/MS, while inter- and intra-day variability was under 15 % in all cases. Most of those data are notably lower than the maximum residue limits established by the European Union for quinolones in pig tissues. The methods have been applied for the determination of quinolones in six different commercial pig muscle samples purchased in different supermarkets located in the city of Granada (south-east Spain).

Particle detector link system modifications in RE1/1 sector

The large hadron collider constructed at the European organization for nuclear research, CERN, is the world’s largest single measuring instrument ever built, and also currently the most powerful particle accelerator that exists. The large hadron collider includes six different experiment stations, one of which is called the compact muon solenoid, or the CMS. The main purpose of the CMS is to track and study residue particles from proton-proton collisions. The primary detectors utilized in the CMS are resistive plate chambers (RPCs). To obtain data from these detectors, a link system has been designed. The main idea of the link system is to receive data from the detector front-end electronics in parallel form, and to transmit it onwards in serial form, via an optical fiber. The system is mostly ready and in place. However, a problem has occurred with innermost RPC detectors, located in sector labeled RE1/1; transmission lines for parallel data suffer from signal integrity issues over long distances. As a solution to this, a new version of the link system has been devised, a one that fits in smaller space and can be located within the CMS, closer to the detectors. This RE1/1 link system has been so far completed only partially, with just the mechanical design and casing being done. In this thesis, link system electronics for RE1/1 sector has been designed, by modifying the existing link system concept to better meet the requirements of the RE1/1 sector. In addition to completion of the prototype of the RE1/1 link system electronics, some testing for the system has also been done, to ensure functionality of the design.

Uptake and factors that influence the use of ‘sit less, move more’ occupational intervention strategies in Spanish office employees

Background Little is known about the types of ‘sit less, move more’ strategies that appeal to office employees, or what factors influence their use. This study assessed the uptake of strategies in Spanish university office employees engaged in an intervention, and those factors that enabled or limited strategy uptake. Methods The study used a mixed method design. Semi-structured interviews were conducted with academics and administrators (n = 12; 44 ± 12 mean SD age; 6 women) at three points across the five-month intervention, and data used to identify factors that influenced the uptake of strategies. Employees who finished the intervention then completed a survey rating (n = 88; 42 ± 8 mean SD age; 51 women) the extent to which strategies were used [never (1) to usually (4)]; additional survey items (generated from interviewee data) rated the impact of factors that enabled or limited strategy uptake [no influence (1) to very strong influence (4)]. Survey score distributions and averages were calculated and findings triangulated with interview data. Results Relative to baseline, 67% of the sample increased step counts post intervention (n = 59); 60% decreased occupational sitting (n = 53). ‘Active work tasks’ and ‘increases in walking intensity’ were the strategies most frequently used by employees (89% and 94% sometimes or usually utilised these strategies); ‘walk-talk meetings’ and ‘lunchtime walking groups’ were the least used (80% and 96% hardly ever or never utilised these strategies). ‘Sitting time and step count logging’ was the most important enabler of behaviour change (mean survey score of 3.1 ± 0.8); interviewees highlighted the motivational value of being able to view logged data through visual graphics in a dedicated website, and gain feedback on progress against set goals. ‘Screen based work’ (mean survey score of 3.2 ± 0.8) was the most significant barrier limiting the uptake of strategies. Inherent time pressures and cultural norms that dictated sedentary work practices limited the adoption of ‘walk-talk meetings’ and ‘lunch time walking groups’. Conclusions The findings provide practical insights into which strategies and influences practitioners need to target to maximise the impact of ‘sit less, move more’ occupational intervention strategies.

Determinação de carbaril utilizando testes ELISA (Enzyme-linked immunosorbent assay) e CLAE com detecção por arranjo de diodos

ELISAs have been applied to pesticide residue analysis due to their high sensitivity and selectivity. However, some ELISAs performance may be affected by matrix components. In this work, ELISA for carbaryl in water samples was checked for interference by naturally occurring fulvic acids. The results suggested that the high fulvic acid concentration (ž³30 mg L-1) and acidic pH conditions (pH 4.0) interfere with the signal detection decreasing the method sensitivity. A dilution of the samples and adjust to pH 8.0 are appropriate to minimize the matrix interferences in the ELISA method. Good correlation between ELISA and HPLC-DAD results was observed.

Relato de uma experiência: recuperação e cadastramento de resíduos dos laboratórios de graduação do Instituto de Química da Universidade Federal do Rio Grande do Sul

An experience aiming to promote a residue interchange and recovery between the teaching laboratories of the Chemistry Institute of this University is described. At the present, several residues interchange have already appeared as advantageous. To make the work easier, a software has been developed in order to keep a record of all the residues generated by the teaching laboratories. Standard labels have been developed for the residues in order to organize them. The software and the label design are described.