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Two different human stones, cystine and cholesterol from the kidney and gall bladder, were examined by time-of-flight sec- ondary ion mass spectrometry using Ga+ primary ions as bombarding particles. The mass spectra of kidney stone were com- pared with those measured for the standard compounds, cystine and cysteine. Similar spectra were obtained for the stone and cystine. The most important identification was based on the existence of the protonated molecules [M+H]+ and deprotonated molecules [M-H]-. The presence of cystine salt was also revealed in the stone through the sodiated cystine [M+Na]+ and the associated fragments, which might be due to the patient treatment history. In the gallstone, the deprotonated molecules [M-H]+ of cholesterol along with relatively intense characteristic fragments [M-OH]+ were detected. Copyright © 2012 John Wiley & Sons, Ltd.

TOF-SIMS VG Ionex IX23LS with upgraded data acquisition and control system was used to study the real urinary stones along with calcium oxalate (COX) and four different calcium phosphate (CP) references. Reliable phase identification of CPs was achieved in the positive SIMS mode on basis of the PO+/POH+ and CaPO2+/Ca2O+ peak ratios. In real urinary stones, pure COX was distinguished from calcium phosphates with confidence via the presence of its characteristic ion peaks. We also quantified the calcium phosphate in the human calculi containing calcium oxalate as major or minor component, which is of a great interest for medical community

SORs (superoxide reductases) are enzymes involved in bacterial resistance to reactive oxygen species, catalysing the reduction of superoxide anions to hydrogen peroxide. So far three structural classes have been identified. Class I enzymes have two ironcentre-containing domains. Most studies have focused on the catalytic iron site (centre II), yet the role of centre I is poorly understood. The possible roles of this iron site were approached by an integrated study using both classical and fast kinetic measurements, as well as direct electrochemistry. A new heterometallic form of the protein with a zinc-substituted centre I, maintaining the iron active-site centre II, was obtained, resulting in a stable derivative useful for comparison with the native all-iron from. Second-order rate constants for the electron transfer between reduced rubredoxin and the different SOR forms were determined to be 2.8 x 10(7) M(-1) . s(-1) and 1.3 x 10(6) M(-1) . s(-1) for SOR(Fe(IIII)-Fe(II)) and for SOR(Fe(IIII)-Fe(III)) forms respectively, and 3.2 x 10(6) M(-1) s(-1) for the SOR(Zn(II)-Fe(III)) form. The results obtained seem to indicate that centre I transfers electrons from the putative physiological donor rubredoxin to the catalytic active iron site (intramolecular process). In addition, electrochemical results show that conformational changes are associated with the redox state of centre I, which may enable a faster catalytic response towards superoxide anion. The apparent rate constants calculated for the SOR-mediated electron transfer also support this observation.

Respiratory nitric oxide reductase (NOR) was purified from membrane extract of Pseudomonas (Ps.) nautica cells to homogeneity as judged by polyacrylamide gel electrophoresis. The purified protein is a heterodimer with subunits of molecular masses of 54 and 18 kDa. The gene encoding both subunits was cloned and sequenced. The amino acid sequence shows strong homology with enzymes of the cNOR class. Iron/heme determinations show that one heme c is present in the small subunit (NORC) and that approximately two heme b and one non-heme iron are associated with the large subunit (NORB), in agreement with the available data for enzymes of the cNOR class. Mossbauer characterization of the as-purified, ascorbate-reduced, and dithionite-reduced enzyme confirms the presence of three heme groups (the catalytic heme b(3) and the electron transfer heme b and heme c) and one redox-active non-heme Fe (Fe(B)). Consistent with results obtained for other cNORs, heme c and heme b in Ps. nautica cNOR were found to be low-spin while Fe(B) was found to be high-spin. Unexpectedly, as opposed to the presumed high-spin state for heme b(3), the Mossbauer data demonstrate unambiguously that heme b(3) is, in fact, low-spin in both ferric and ferrous states, suggesting that heme b(3) is six-coordinated regardless of its oxidation state. EPR spectroscopic measurements of the as-purified enzyme show resonances at the g approximately 6 and g approximately 2-3 regions very similar to those reported previously for other cNORs. The signals at g = 3.60, 2.99, 2.26, and 1.43 are attributed to the two charge-transfer low-spin ferric heme c and heme b. Previously, resonances at the g approximately 6 region were assigned to a small quantity of uncoupled high-spin Fe(III) heme b(3). This assignment is now questionable because heme b(3) is low-spin. On the basis of our spectroscopic data, we argue that the g = 6.34 signal is likely arising from a spin-spin coupled binuclear center comprising the low-spin Fe(III) heme b(3) and the high-spin Fe(B)(III). Activity assays performed under various reducing conditions indicate that heme b(3) has to be reduced for the enzyme to be active. But, from an energetic point of view, the formation of a ferrous heme-NO as an initial reaction intermediate for NO reduction is disfavored because heme [FeNO](7) is a stable product. We suspect that the presence of a sixth ligand in the Fe(II)-heme b(3) may weaken its affinity for NO and thus promotes, in the first catalytic step, binding of NO at the Fe(B)(II) site. The function of heme b(3) would then be to orient the Fe(B)-bound NO molecules for the formation of the N-N bond and to provide reducing equivalents for NO reduction.

Spreadsheets are widely used, and studies have shown that most end-user spreadsheets contain non-trivial errors. To improve end-users productivity, recent research proposes the use of a model-driven engineering approach to spreadsheets. In this paper we conduct the first systematic empirical study to assess the effectiveness and efficiency of this approach. A set of spreadsheet end users worked with two different model-based spreadsheets, and we present and analyze here the results achieved.

A forelimb of a new sauropod dinosaur (Angolatitan adamastor n. gen. et sp.) from the Late Turonian of Iembe (Bengo Province) represents the first dinosaur discovery in Angola, and is one of the few occurrences of sauropod dinosaurs in sub-Saharan Africa collected with good chronological controls. The marginal marine sediments yielding the specimen are reported to be late Turonian in age and, thus it represents a non-titanosaurian sauropod in sub-Saharan Africa at a time taken to be dominated by titanosaurian forms. Moreover, Angolatitan adamastor is the only basal Somphospondyli known in the Late Cretaceous which implies in the existence of relict forms in Africa.

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The activation mechanism of Pseudomonas stutzeri cytochrome c peroxidase (CCP) was probed through the mediated electrochemical catalysis by its physiological electron donor, P. stutzeri cytochrome c-551. A comparative study was carried out, by performing assays with the enzyme in the resting oxidized state as well as in the mixed-valence activated form, using cyclic voltammetry and a pyrolytic graphite membrane electrode. In the presence of both the enzyme and hydrogen peroxide, the peak-like signal of cytochrome c-551 is converted into a sigmoidal wave form characteristic of an E(r)C'(i) catalytic mechanism. An intermolecular electron transfer rate constant of (4 +/- 1) x 10(5) M(-1) s(-1) was estimated for both forms of the enzyme, as well as a similar Michaelis-Menten constant. These results show that neither the intermolecular electron transfer nor the catalytic activity is kinetically controlled by the activation mechanism of CCP in the case of the P. stutzeri enzyme. Direct enzyme catalysis using protein film voltammetry was unsuccessful for the analysis of the activation mechanism, since P. stutzeri CCP undergoes an undesirable interaction with the pyrolytic graphite surface. This interaction, previously reported for the Paracoccus pantotrophus CCP, induces the formation of a non-native conformation state of the electron-transferring haem, which has a redox potential 200 mV lower than that of the native state and maintains peroxidatic activity.

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Software transactional memory is a promising programming model that adapts many concepts borrowed from the databases world to control concurrent accesses to main memory (RAM). This paper discusses how to support revertible operations, such as memory allocation and release, within software libraries that will be used in software memory transactional contexts. The proposal is based in the extension of the transaction life cycle state diagram with new states associated to the execution of user-defined handlers. The proposed approach is evaluated in terms of functionality and performance by way of a use case study and performance tests. Results demonstrate that the proposal and its current implementation are flexible, generic and efficient

This paper is a review over a variety of events which lead to disruption conditions in supply chains and identifies correspondent resilient strategies for each condition. The paper objective is to make a link between the problems created by events and strategies that managers can use to avoid or mitigate the negative aspects of those problems and improve post- event recovery. To attain the paper objectives it was use archived media news to collect empirical data about disturbances (events), their negative effects (problems), and resilience strategies. In the data collection phase, the aim was to keep diversities and be comprehensive. Using empirical evidences from the sample is developed a graph to show the links between supply chain disturbances, problems and resilience. This research provides supply chain managers with some alternative strategies to opt for the best available decision, improving the post-event management process.

The evolution of wine after bottling may be affected by the continuous supply of oxygen through the closures. I n the case of cork, oxygen may come from two different sources: permeation from outside through the cork and the release of gas from inside cork cells. I n this work we studied this later issue. The typical compression rate (volume change / uncompressed volume) of a cork stopper is about 40%. Taking in account that cork has a void volume ranging 70 to 80°/o cork cells pressure after bottling may reach 2 atm. This pressurized gas will 'escape' to both sides of the closure along many weeks. I n this work we measured the gas flow coming from cork stoppers in 3 typical starting headspace pressures: 60 mbar, 1000 mbar and 3000 mbar (absolute pressures). These conditions correspond roughly to vacuum bottling, balanced pressures bottling and bottling without any prior pumping. These experiments were performed by continuous monitoring the pressure, with a high accuracy gauge, in the headspace along several weeks keeping the bottleneck volume at constant temperature. In the case of vacuum bottling the headspace pressure continuously rises for many weeks. With balanced pressures, the pressure rises for a few days and then starts decreasing. I n the case of bottling without pumping the headspace pressure is typically higher than the cork cells pressure leading to a continuous pressure loss. These results together with those from permeation of cork provide a useful picture to those who need to know quantitavely the amount of oxygen in contact with wine in the post bottling period. (Bulletin de I'OIV, 2011, vol. 84, n0965-966-967, p. 261-269)

Superoxide reductases are enzymes involved in bacterial resistance to reactive oxygen species, catalyzing the reduction of superoxide anions to hydrogen peroxide. So far three structural classes have been identified. Class I enzymes have two iron-center containing domains. Most studies have been focused on the catalytic iron site (center II), but the role of center I is yet poorly understood. The possible roles of this iron site were approached by an integrated study using both classical and fast kinetics measurements as well as direct electrochemistry. A new heterometallic form of the protein with a zinc-substituted center I, maintaining the iron active site center II was obtained, resulting in a stable derivative useful for comparison with the native all-iron from. Second order rate constants for the electron transfer between reduced rubredoxin and the different SOR forms were determined to be 2.8x107 (M-1s-1) and 1.3x106 (M-1s-1) for SORFe(IIII)-Fe(II) and for SORFe(IIII)-Fe(III) forms respectively, and 3.2x106 (M-1s-1) for the SORZn(II)-Fe(III) form. The results obtained seem to indicate that center I transfers electrons from the putative physiologic donor, rubredoxin, to the catalytic active iron site (intramolecular process). In addition, electrochemical results show that conformational changes are associated to the redox state of center I, which may enable a faster catalytic response towards superoxide anion. The apparent rate constants calculated for the SOR-mediated electron transfer also support this observation.

The permeability of gases through uncompressed cork was investigated. More than 100 samples were assessed from different plank qualities to provide a picture of the permeability distribution. A novel technique based on a mass spectrometer leak detector was used to directly measure the helium flow through the central area of small disks 10 mm in diameter and 2 mm thick. The permeability for nitrogen, oxygen, and other gases was measured by the pressure rise technique. Boiled and nonboiled cork samples from different sections were evaluated. An asymmetric frequency distribution ranging 3 orders of magnitude (roughly from 1 to 1000 $μ$mol/(cm·atm·day)) for selected samples without macroscopic defects was found, having a peak below 100 $μ$mol/(cm·atm·day). Correlation was found between density and permeability: higher density samples tend to show lower permeability. However, boiled cork showed a mean lower permeability despite having a lower density. The transport mechanism of gases through cork was also examined. Calculations suggest that gases permeate uncompressed cork mainly through small channels between cells under a molecular flow regime. The diameter of such channels was estimated to be in the range of 100 nm, in agreement with the plasmodesmata size in the cork cell walls.

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