CO2 pipelines material and safety considerations

This paper presents an overview of some of the most important factors and areas of uncertainty affecting integrity and accurate hazard assessment of CO2 pipelines employed as part of the Carbon Capture and Sequestration (CCS) chain. These include corrosion, hydrate formation, hydrogen embrittlement and propensity to fast running ductile and brittle factures. Special consideration is given to the impact of impurities within the CO2 feed from the various capture technologies on these possible hazards. Knowledge gaps in the modelling of outflow and subsequent dispersion of CO2 following the accidental rupture of pressurised CO2 pipelines, central to their safety assessment, are also presented

Protestant mission work among Italians in Boston

This item was digitized by the Internet Archive

Η ανοσιακή απάντηση στον CMV σε ανοσοκατασταλμένους ασθενείς

Η αλλογενής μεταμόσχευση αρχέγονων αιμοποιητικών κυττάρων (ΜΑΑΚ) αποτελεί καίρια και σωτήρια θεραπεία για την πλειονότητα των παιδιών που πάσχουν από κακοήθεις και μη κακοήθεις αιματολογικές παθήσεις. Ωστόσο όπως συμβαίνει και με τους ενήλικες, οι παιδιατρικοί μεταμοσχευμένοι ασθε νείς βρίσκονται σε υψηλό κίνδυνο νόσου από επανενεργοποίηση του CMV. Αυτό είναι αποτέλεσμα τόσο του ανώριμου ανοσοποιητικού τους συστήματος όσο και της κατασταλτικής θεραπείας που ακολουθεί την μεταμόσχευση. Πρά γματι η CMV λοίμωξη μπορεί όχι μόνο να προκαλέσει σοβαρή νόσο με προ σβολή πολλών οργάνων όπως αμφιβληστροειδοπάθεια, γαστρεντερίτιδα, εγκε φαλίτιδα, ηπατίτιδα, πνευμονίτιδα, μυοκαρδίτιδα αλλά και επιπλοκές όπως βα κτηριακές και μυκητιασικές λοιμώξεις, απόρριψη μοσχεύματος και νόσο μο σχεύματος έναντι ξενιστή (GVHD). Αρκετές μελέτες που έχουν γίνει κυρίως σε ενήλικες μεταμοσχευμένους ασθενείς έδειξαν ότι η αποκατάσταση της ειδικής για τον CMV Τ-κυτταρικής ανοσίας σχετίζεται με τον έλεγχο και την προστασία έναντι του ιού. Επομένως μετρώντας την κυτταρική ανοσιακή απάντηση στον CMV των ασθενών αυτών θα μπορούμε να υπολογίσουμε τον κίνδυνο για CMV λοίμωξη και να εφαρμόσουμε εξατομικευμένες στρατηγικές διαχείρισης. Στην παρούσα φάση υπάρχουν διαθέσιμες αρκετές ανοσολογικές δοκιμασίες για την παρακολούθηση της ειδικής για τον CMV ανοσιακής απάντησης για τους μεταμοσχευμένους ασθενείς. Όμως, είναι ακριβές, δεν είναι ευρέως διαθέσιμες και συχνά απαιτούν εξειδικευμένο εργαστηριακό εξοπλισμό ενώ επίσης δεν είναι προτυποποιημένες. Για το λόγο αυτό, μελετήσαμε προοπτικά τη χρησιμότητα στην κλινική πράξη της παρακολούθησης της ειδικής για τον CMV ανοσιακής απάντησης με τη δοκιμασία QuantiFERON®-CMV (QIAGEN), στην πρόβλεψη ιαιμίας από CMV σε παιδιά που έχουν υποβληθεί σε μεταμόσχευση αρχέγονων αιμοποιητικών κυττάρων. Στη μελέτη συμμετείχαν 37 παιδιά που έλαβαν αλλογενή ΜΑΑΚ τη διετία 3/2010-6/2012. Η ανίχνευση της ιαιμίας από CMV γινόταν εβδομαδιαία με real time PCR . Η παρακολούθηση της ανοσιακής αποκατάστασης γινόταν με τη δοκιμασία QuantiFERON®-CMV προ μεταμόσχευσης, νωρίς μετά την μεταμόσχευση, στις 30, 90,180, 270 και 360 ημέρες μετά την μεταμόσχευση. Η επίπτωση της ιαιμίας από CMV ήταν 51% (19/37) με τα μισά επεισόδια να συμβαίνουν μέσα στις ≤30 μέρες από τη μεταμόσχευση. Δεκαπέντε ασθενείς παρουσίασαν σταθερή ειδική ανοσία στον CMV σε ένα μέσο χρονικό διάστη μα 82 ημερών. Η αθροιστική επίπτωση (cumulative incidence) της επανενερ γοποίησης του CMV στους ασθενείς που ανέπτυξαν ειδική για τον ιό ανοσία ήταν χαμηλότερη σε σχέση με αυτούς που δεν ανέπτυξαν (15% έναντι 53%; p=0.023). Για την εκτίμηση της προβλεπτικής αξίας της μεθόδου στην εμφά νιση ιαιμίας από CMV έγινε στατιστική ανάλυση ROC (receiver operating characteristic) όπου ανέδειξε περιοχή κάτω από την καμπύλη 0.725. Συμπερασματικά, σε αυτή την κοορτή παιδιατρικών ασθενών με ΜΑΑΚ, η θετική QuantiFERON®-CMV συσχετίστηκε με χαμηλό κίνδυνο υποτροπής CMV ιαιμίας, αντανακλώντας σαφώς την αποκατάσταση της κυτταρικής ανοσίας για τον CMV. Η μέθοδος αυτή αποδείχθηκε αξιόλογη στην αναγνώ ριση παιδιατρικών ασθενών ΜΑΑΚ σε υψηλό κίνδυνο για CMV ιαιμία. Ως εκ τούτου θα μπορούσε να ενισχύσει την καθιερωμένη επιτήρηση και την διαστρωμάτωση του κινδύνου για τον CMV μετά την μεταμόσχευση. Κατά συνέπεια, οι ασθενείς με εδραιωμένη ανοσιακή απάντηση στον CMV βάσει της μεθόδου θα μπορούσαν να υποβάλονται σε λιγότερο εντατικά σχήματα παρακολούθησης και εξατομικευμένα προγράμματα προφυλακτικής αγωγής.Allogeneic hematopoietic stem cell transplantation (HSCT) is a life-saving procedure for children suffering from malignant and non malignant diseases. Pediatric hematopoietic stem cell transplant (HSCT) recipients are at high risk for cytomegalovirus (CMV) reactivation due to their immature immune system and therapy following transplantation. Indeed, not only can CMV infection cause severe and multi-organ disease such as retinitis, gastroenteritis, encephalitis, hepatitis, pneumonitis, myocarditis, but it is also associated with the development of bacterial or fungal infections, graft rejection or graft-versus-host-disease (GVHD). Several studies mostly in adult transplant recipients have demonstrated that reconstitution of CMV specific T-cell immunity is associated with control and protection against CMV. Therefore, measuring a patient’s CMI response to CMV may help determine the risk of CMV infection as well as individualize management strategies. At present, several immunological assays are available for monitoring CMV-specific T-cell-mediated immune responses in transplant recipients. However, they are expensive, often require laboratory expertise, and are neither widely available nor standardized. In this study, the clinical utility of monitoring CMV-specific cell mediated immunity to predict CMV viremia in pediatric HSCT patients using the QuantiFERON®-CMV (QIAGEN) test was investigated prospectively. Thirty seven pediatric allogeneic HSCT recipients were enrolled from 3/2010-6/2012. CMV viremia was detected via weekly real time PCR. The QuantiFERON®-CMV test was conducted pre-transplant, early after transplantation, 30, 90, 180, 270 and 360 days post-transplantation. The incidence of CMV viremia was 51% (19/37) with half of the episodes within ≤ 30 days post-transplant. Fifteen patients showed stable CMV-specific immunity at an average time of 82 days. The cumulative incidence of CMV reactivation in patients who developed CMV-specific immunity was lower than those who did not (15% versus 53%; p=0.023). The receiver operating characteristic (ROC) statistical analysis showed that the area under curve was 0.725 in predicting viremia for QuantiFERON®-CMV test. In conclusion, in this cohort of HSCT pediatric patients, positive QuantiFERON®-CMV was associated with a low risk of recurrent CMV viremia, accurately reflecting CMV CMI recovery. The QuantiFERON®-CMV assay was a valuable method for identifying pediatric HSCT patients at high risk for CMV viremia. This assay could complement the monitoring and stratification of CMV risk of pediatric patients post-transplantation. Therefore, pediatric patients with positive CMV CMI tests might benefit from less intense surveillance and individualized prophylactic treatment plans

Electron Tunneling in Single Crystals of Pseudomonas aeruginosa Azurins

Rates of reduction of Os(III), Ru(III), and Re(I)^* by Cu(I) in His83-modified Pseudomonas aeruginosa azurins (M−Cu distance ∼17 Å) have been measured in single crystals, where protein conformation and surface solvation are precisely defined by high-resolution X-ray structure determinations:  1.7(8) × 10^6 s^(-1) (298 K), 1.8(8) × 10^6 s^(-1) (140 K), [Ru(bpy)_2(im)^(3+)-]; 3.0(15) × 10^6 s^(-1) (298 K), [Ru(tpy)(bpy)^(3+)-]; 3.0(15) × 10^6 s^(-1) (298 K), [Ru(tpy)(phen)^(3+)-]; 9.0(50) × 10^2 s^(-1) (298 K), [Os(bpy)2(im)^(3+)-]; 4.4(20) × 10^6 s^(-1) (298 K), [Re(CO)_3(phen)^(+*)] (bpy = 2,2‘-bipyridine; im = imidazole; tpy = 2,2‘:6‘,2‘ ‘-terpyridine; phen = 1,10-phenanthroline). The time constants for electron tunneling in crystals are roughly the same as those measured in solution, indicating very similar protein structures in the two states. High-resolution structures of the oxidized (1.5 Å) and reduced (1.4 Å) states of Ru(II)(tpy)(phen)(His83)Az establish that very small changes in copper coordination accompany reduction but reveal a shorter axial interaction between copper and the Gly45 peptide carbonyl oxygen [2.6 Å for Cu(II)] than had been recognized previously. Although Ru(bpy)_2(im)(His83)Az is less solvated in the crystal, the reorganization energy for Cu(I) → Ru(III) electron transfer falls in the range (0.6−0.8 eV) determined experimentally for the reaction in solution. Our work suggests that outer-sphere protein reorganization is the dominant activation component required for electron tunneling

Relaxation Dynamics of Pseudomonas aeruginosa Re^I(C)O_3(α-diimine)(HisX)^+ (X=83, 107, 109, 124, 126)Cu-^(II) Azurins

Photoinduced relaxation processes of five structurally characterized Pseudomonas aeruginosa Re^I(CO)_3(α-diimine)(HisX) (X = 83, 107, 109, 124, 126)Cu^(II) azurins have been investigated by time-resolved (ps−ns) IR spectroscopy and emission spectroscopy. Crystal structures reveal the presence of Re-azurin dimers and trimers that in two cases (X = 107, 124) involve van der Waals interactions between interdigitated diimine aromatic rings. Time-dependent emission anisotropy measurements confirm that the proteins aggregate in mM solutions (D2O, KPi buffer, pD = 7.1). Excited-state DFT calculations show that extensive charge redistribution in the ReI(CO)_3 → diimine ^3MLCT state occurs: excitation of this ^3MLCT state triggers several relaxation processes in Re-azurins whose kinetics strongly depend on the location of the metallolabel on the protein surface. Relaxation is manifested by dynamic blue shifts of excited-state ν(CO) IR bands that occur with triexponential kinetics: intramolecular vibrational redistribution together with vibrational and solvent relaxation give rise to subps, 2, and 8−20 ps components, while the ~10^2 ps kinetics are attributed to displacement (reorientation) of the Re^I(CO)_3(phen)(im) unit relative to the peptide chain, which optimizes Coulombic interactions of the Re^I excited-state electron density with solvated peptide groups. Evidence also suggests that additional segmental movements of Re-bearing β-strands occur without perturbing the reaction field or interactions with the peptide. Our work demonstrates that time-resolved IR spectroscopy and emission anisotropy of Re^I carbonyl−diimine complexes are powerful probes of molecular dynamics at or around the surfaces of proteins and protein−protein interfacial regions

Elucidation of a Low Spin Cobalt(II) System in a Distorted Tetrahedral Geometry

We have prepared a series of divalent cobalt(II) complexes supported by the [PhBP_3] ligand ([PhBP_3] = [PhB(CH_2PPh_2)_3]-) to probe certain structural and electronic phenomena that arise from this strong field, anionic tris(phosphine) donor ligand. The solid-state structure of the complex [PhBP_3]CoI (1), accompanied by SQUID, EPR, and optical data, indicates that it is a pseudotetrahedral cobalt(II) species with a doublet ground state the first of its type. To our knowledge, all previous examples of 4-coordinate cobalt(II) complexes with doublet ground states have adopted square planar structure types. Complex 1 provided a useful precursor to the corresponding bromide and chloride complexes, {[PhBP_3]Co(μ-Br)}_2, (2), and {[PhBP_3]Co(μ-Cl)}_2, (3). These complexes were similarly characterized and shown to be dimeric in the solid-state. In solution, however, the monomeric low spin form of 2 and 3 dominates at 25 °C. There is spectroscopic evidence for a temperature-dependent monomer/dimer equilibrium in solution for complex 3. Furthermore, the dimers 2 and 3 did not display appreciable antiferromagnetic coupling that is typical of halide and oxo-bridged copper(II) and cobalt(II) dimers. Rather, the EPR and SQUID data for solid samples of 2 and 3 suggest that they have triplet ground states. Complexes 1, 2, and 3 are extremely oxygen sensitive. Thus, stoichiometric oxidation of 1 by dioxygen produced the 4-coordinate, high spin complex [PhB(CH_2P(O)Ph_2)_2(CH_2PPh_2)]CoI, (4), in which the [PhBP_3] ligand had undergone a 4-electron oxidation. Reaction of 1 with TlOAr (Ar = 2,6-Me_2Ph) afforded an example of a 4-coordinate, high spin complex, [PhBP_3]Co(O-2,6-Me_2Ph) (5), with an intact [PhBP_3] ligand. The latter two complexes were spectroscopically and structurally characterized for comparison to complexes 1, 2, and 3. Our data for these complexes collectively suggest that the [PhBP_3] ligand provides an unusually strong ligand-field to these divalent cobalt complexes that is chemically distinct from typical tris(phosphine) donor ligand sets, and distinct from tridentate borato ligands that have been previously studied. Coupling this strong ligand-field with a pronounced axial distortion away from tetrahedral symmetry, a geometric consequence that is enforced by the [PhBP_3] ligand, provides access to monomeric [PhBP_3]CoX complexes with doublet rather than quartet ground states

Electron tunneling in biological molecules

Electron transfers in photosynthesis and respiration commonly occur between protein-bound prosthetic groups that are separated by large molecular distances (often greater than 10Å). Although the electron donors and acceptors are expected to be weakly coupled, the reactions are remarkably fast and proceed with high specificity. Tunneling timetables based on analyses of Fe^(2+)/Cu^+ to Ru^(3+) electron-transfer rates for Ru-modified heme and copper proteins reveal that the structure of the intervening polypeptide can control these distant donor-acceptor couplings. Multistep tunneling can account for the relatively rapid Cu^+ to Re^(2+) electron transfer observed in Re-modified azurin

Electron-Transfer Chemistry of Ru−Linker−(Heme)-Modified Myoglobin: Rapid Intraprotein Reduction of a Photogenerated Porphyrin Cation Radical

We report the synthesis and characterization of RuC7, a complex in which a heme is covalently attached to a [Ru(bpy)_3]^(2+) complex through a −(CH_2)_7− linker. Insertion of RuC7 into horse heart apomyoglobin gives RuC7Mb, a Ru(heme)−protein conjugate in which [Ru(bpy)_3]^(2+) emission is highly quenched. The rate of photoinduced electron transfer (ET) from the resting (Ru^(2+)/Fe^(3+)) to the transient (Ru^(3+)/Fe^(2+)) state of RuC7Mb is >10^8 s^(-1); the back ET rate (to regenerate Ru^(2+)/Fe^(3+)) is 1.4 × 10^7 s^(-1). Irreversible oxidative quenching by [Co(NH_3)_5Cl]^(2+) generates Ru^(3+)/Fe^(3+):  the Ru^(3+) complex then oxidizes the porphyrin to a cation radical (P^(•+)); in a subsequent step, P^(•+) oxidizes both Fe^(3+) (to give Fe^(IV)═O) and an amino acid residue. The rate of intramolecular reduction of P^(•+) is 9.8 × 10^3 s^(-1); the rate of ferryl formation is 2.9 × 10^3 s^(-1). Strong EPR signals attributable to tyrosine and tryptophan radicals were recorded after RuC7MbM^(3+) (M = Fe, Mn) was flash-quenched/frozen

X-ray Magnetic Circular Dichroism of Pseudomonas aeruginosa Nickel(II) Azurin

We show that X-ray magnetic circular dichroism (XMCD) can be employed to probe the oxidation states and other electronic structural features of nickel active sites in proteins. As a calibration standard, we have measured XMCD and X-ray absorption (XAS) spectra for the nickel(II) derivative of Pseudomonas aeruginosa azurin (NiAz). Our analysis of these spectra confirms that the electronic ground state of NiAz is high-spin (S = 1); we also find that the L3-centroid energy is 853.1(1) eV, the branching ratio is 0.722(4), and the magnetic moment is 1.9(4) μ_B. Density functional theory (DFT) calculations on model NiAz structures establish that orbitals 3d_x^2-y^2 and 3d_z^2 are the two valence holes in the high-spin Ni(II) ground state, and in accord with the experimentally determined orbital magnetic moment, the DFT results also demonstrate that both holes are highly delocalized, with 3d_x^2_(-y)^2 having much greater ligand character

Qualea grandiflora Mart.: TEMPERATURA NA GERMINABILIDADE DE SEMENTES

Qualea grandiflora Mart. occurs in riverine forests and in 'cerrado' areas, popularly known as 'pauterra'. With the purpose of obtaining information about the reproductive spread of this species, it was studied the effect of temperature on seed germination capability. The temperatures used were: 15, 20, 25, 30, 35 and 40 \ub0C. The seeds were sown on paper towel in roll form, with four replicates of one experimental unit consisted of a roll with 25 seeds. The experiment followed a completely randomized design with six treatments and four replications. There was primary root emission at temperatures of 15 to 40 \ub0C. Values between 78 % and 93 % were obtained in a wide range of temperatures between 15 and 35 \ub0C. A normal seedling occurred in narrower range, between 20 and 35 \ub0C. The protrusion of the root began on the seventh day after sowing, except the 15 \ub0C which provided a slow and gradual process, beginning on the fourteenth day after hatching. At 40 \ub0C, the germination capability was less than 15 % and there was no normal seedling. For the seed germination of 'pau-terra', it is recommended that the temperature range between 20 and 30 \ub0C.Qualea grandiflora Mart. ocorre em matas de galeria e cerrado, sendo conhecida popularmente como pauterra. Com o objetivo de obter informa\ue7\uf5es sobre a propaga\ue7\ue3o reprodutiva dessa esp\ue9cie foi estudado o efeito da temperatura sobre a germinabilidade das sementes. As temperaturas utilizadas foram: 15, 20, 25, 30, 35 e 40 \ub0C. As sementes foram semeadas em substrato papel-toalha, na forma de rolo, com quatro repeti\ue7\uf5es, sendo a unidade experimental constitu\uedda por um rolo com 25 sementes. O experimento seguiu o delineamento inteiramente casualizado com seis tratamentos e quatro repeti\ue7\uf5es. Houve emiss\ue3o de raiz prim\ue1ria em temperaturas de 15 a 40 \ub0C. Valores entre 78 e 93 % foram obtidos numa ampla faixa de temperaturas, entre 15 e 35 \ub0C. A forma\ue7\ue3o de pl\ue2ntulas normais ocorreu em faixa mais restrita, entre 20 e 35 \ub0C. A protrus\ue3o de raiz iniciou no s\ue9timo dia ap\uf3s a semeadura, exceto a 15 \ub0C que proporcionou um processo lento e gradativo, iniciando no d\ue9cimo quarto dia ap\uf3s a incuba\ue7\ue3o. A 40 \ub0C a germinabilidade foi inferior a 15 % e n\ue3o houve forma\ue7\ue3o de pl\ue2ntulas normais. Para germina\ue7\ue3o de sementes de pau-terra, recomenda-se a faixa de temperatura entre 20 e 30 \ub0C