The oxidation of glucose and some of its derivatives by chlorine in acid aqueous solution

Thesis (Ph.D.)--Boston UniversityThis work was undertaken to extend the knowledge of chlorine water oxidations of carbohydrates in the acid range. The simplest models of cellulose, namely D-glucose and alkyl-β-D-glucosides, were used as reductants. The oxidation of glucono-δ-lactone has also been studied. Reductants were always present in great excess. The reaction vessel was a hypodermic syringe with an adapter. This vessel prevented the loss of chlorine through volatilization. Samples were periodically withdrawn, quenched and titrated. Specific rates of reaction were determined from the data. In all cases where the rate constant increased with time, the slope was determined from the initial portion of the run. The reaction is first order in oxidant and reductant for all substrates except methyl-α-D-glucoside. Methyl-α-D-glucoside exhibits a zero order dependence on the oxidant concentration and a variable order (0≤n≤1) in reductant. The specific reaction rates for molecular chlorine and hypochlorous acid oxidations of all substrates have been obtained and are recorded below. The separation of catalytic (generalized base and nucleophilic) effects related to chlorine and hypochlorous acid was realized. Specific and generalized acid catalysis were proved to be absent in the case of D-glucose. In general, specific and generalized acid catalysis was assumed to be negligible in the oxidation of all substrates. Hypo-chlorite ion proved to be a potent catalyst - more effective than the Bronsted catalysis law would indicate. The sole exception to generalized base catalysis was obtained using glucono-δ-lactone as substrate. The oxidation of this substrate was inhibited by the presence of monohydrogen phosphate ion. [Table 1: Stoichiometric data of chlorine water oxidations of carbohydrates in the acid range] The pseudo zero order behavior in oxidant experienced with methyl-α-D-glucoside is explained on the basis of two consecutive (1) liter/mole - second (2) liters^2/mole^2 - second reactions with the second reaction being very rapid relative to the first. Thus a rate expression was derived which explained the kinetics, i.e., v = k (Ox)o (G) where (Ox)o = initial oxidant concentration (G) =methyl-α-D-glucoside concentration. The oxidation of this substrate is slow in comparison with D-glucose and the alkyl-β-D-glucosides. These data in addition to the stoichiometry data support the above conclusion that the second reaction is much faster than the first. The reaction was also found to be susceptible to chloride ion catalysis. The presence of chloride ion was found to inhibit the oxidation of methyl-β-, isobutyl-β-, and isopropyl-β-D-glucoside by hypochlorous acid. This is a distinct difference from the α anomer and suggests a change in mechanism. The differences in rate and catalytic constants for the β-glucosides are small and suggest that the structure of the aglycon does not influence the rate of oxidation. The stoichiometry values determined under conditions of excess oxidant have been determined for D-glucose (pH 2.1, 2.8, 4.6 and 6.3), methyl-α-D-glucoside, methyl-β-D-glucoside and isopropyl-β-D-glucoside, all at pH 2.1, 4.6 and 6.3. Lowest values of equivalents of oxidant consumed per mole of reductant are obtained in the regions of highest acidity

Omentum is highly effective in the management of complex cardiothoracic surgical problems

AbstractObjectives: Vascularized, pedicled tissue flaps are often used for cardiothoracic surgical problems complicated by factors that adversely affect healing, such as previous irradiation, established infection, or steroid use. We reviewed our experience with use of the omentum in these situations to provide a yardstick against which results with other vascularized flaps (specifically muscle flaps) could be compared. Methods: A retrospective review was undertaken of 85 consecutive patients in whom omentum was used in the chest. In 47 patients (group I), use of omentum was prophylactic to aid in the healing of closures or anastomoses considered to be at high risk for failure. In 32 patients (group II), omentum was used in the treatment of problems complicated by established infection. In 6 patients (group III), omentum was used for coverage of prosthetic chest wall replacements after extensive chest wall resection. Results: Overall, omental transposition was successful in its prophylactic or therapeutic purpose in 88% of these difficult cases (75/85). Success with omentum was achieved for 89% of patients (42/47) in group I, 91% of patients (29/32) in group II, and 67% of patients (4/6) in group III. Three patients (3.5%) had complications of omental mobilization. Four patients (4.7%) died after the operation as a result of failure of the omentum to manage the problem for which it was used. Conclusions: Results with omental transposition compare favorably with published series of similarly challenging cases managed with muscle transposition. Complications of omental mobilization are rare. We believe that its unique properties render the omentum an excellent choice of vascularized pedicle in the management of the most complex cardiothoracic surgical problems.J Thorac Cardiovasc Surg 2003;125:526-3

Malta : language, literacy and identity in a Mediterranean island society

Available documentation for the early modern period indicates that the Malta harbor towns achieved literacy earlier than the countryside. The Maltese townsmen lived on a trading route, and it was necessary for them to learn the lingua franca, as the language of trade in the Mediterranean. The educated elite were able to acquire fluent speaking knowledge, as well as the ability to write, Tuscan (a dialect then in the process of becoming standard Italian), while continuing to employ their local Maltese ‘dialect’ on numerous occasions. By and large, the erosion of the position of Maltese as the subordinate language was an inevitable by-product of this development. The Maltese language was able to attain the function of a literary language in the nineteenth century but it had no standard orthography until 1931 and was only adopted as Malta’s official language in 1964.peer-reviewe

European traditional tomatoes galore: a result of farmers’ selection of a few diversity-rich loci

A comprehensive collection of 1254 tomato accessions, corresponding to European traditional and modern varieties, early domesticated varieties, and wild relatives, was analyzed by genotyping by sequencing. A continuous genetic gradient between the traditional and modern varieties was observed. European traditional tomatoes displayed very low genetic diversity, with only 298 polymorphic loci (95% threshold) out of 64 943 total variants. European traditional tomatoes could be classified into several genetic groups. Two main clusters consisting of Spanish and Italian accessions showed higher genetic diversity than the remaining varieties, suggesting that these regions might be independent secondary centers of diversity with a different history. Other varieties seem to be the result of a more recent complex pattern of migrations and hybridizations among the European regions. Several polymorphic loci were associated in a genome-wide association study with fruit morphological traits in the European traditional collection. The corresponding alleles were found to contribute to the distinctive phenotypic characteristic of the genetic varietal groups. The few highly polymorphic loci associated with morphological traits in an otherwise a low-diversity population suggests a history of balancing selection, in which tomato farmers likely maintained the morphological variation by inadvertently applying a high selective pressure within different varietal types.This work was supported by the European Commission H2020 research and innovation program through TRADITOM grant agreement no. 634561, G2P-SOL, grant agreement no. 677379, and HARNESSTOM grant agreement no. 101000716. MP is grateful to the Spanish Ministerio de Ciencia e Innovación for a postdoctoral grant (IJC2019-039091-I/AEI/10.13039/501100011033).Postprint (published version

Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

The Data Acquisition and Calibration System for the ATLAS Semiconductor Tracker

The SemiConductor Tracker (SCT) data acquisition (DAQ) system will calibrate, configure, and control the approximately six million front-end channels of the ATLAS silicon strip detector. It will provide a synchronized bunch-crossing clock to the front-end modules, communicate first-level triggers to the front-end chips, and transfer information about hit strips to the ATLAS high-level trigger system. The system has been used extensively for calibration and quality assurance during SCT barrel and endcap assembly and for performance confirmation tests after transport of the barrels and endcaps to CERN. Operating in data-taking mode, the DAQ has recorded nearly twenty million synchronously-triggered events during commissioning tests including almost a million cosmic ray triggered events. In this paper we describe the components of the data acquisition system, discuss its operation in calibration and data-taking modes and present some detector performance results from these tests