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We present a comprehensive analysis of the seasonal variability of the vertical profiles of the optical and geometrical properties of Saharan dust aerosols, observed in the height region between 1000 and 6000 m, over the city of Athens, Greece, from February 2000 to December 2016. These observations were performed by a multi-wavelength (355-387-532-1064 nm) Raman lidar system under cloud-free conditions. The statistical analysis (using aerosol monthly mean values) is based on nighttime vertical Raman measurements of range-resolved aerosol optical properties (backscatter and extinction coefficients, lidar ratio, Ångström exponent) at 355 nm (57 dust events during more than 80 measurement hours). We found that the number of dust events was highest in spring, summer, and early autumn periods and that during spring the dust layers were moved at higher altitudes (∼4500 m) than in other seasons. The number of the forecasted dusty days (on monthly basis) by the BSC-DREAM8b model compared to those of the performed lidar measurements were found to have a quite strong correlation (R 2  = 0.81), with a maximum occurrence predicted for the spring season. In the worst case scenario, at least 50% of the model-forecasted dust events can be observed by lidar under cloudless skies over Athens. For the sampled dust plumes we found mean lidar ratios of 52 ± 13 sr at 355 nm in the height range 2000–4000 m a.s.l. Moreover, the dust layers had a mean thickness of 2497 ± 1026 m and a center of mass of 2699 ± 1017 m. An analysis performed regarding the air mass back-trajectories arriving over Athens revealed two main clusters: one pathway from south-west to north-east, with dust emission areas in Tunisia, Algeria and Libya and a second one from south, across the Mediterranean Sea with emission areas over Libya and the remaining part of Algeria and Tunisia. This clustering enabled us to differentiate between the aerosol optical properties between the two clusters, based on their residence time over the Saharan region, the European continent and the Mediterranean Sea. We finally concluded that even if the dust source regions are about the same, the aging and mixing processes of these air masses, passing over different areas, might have an impact on the aerosol optical properties. [ABSTRACT FROM AUTHOR]

The reaction mechanism, of the ethanethiol transformation over acidic zeolite surface: ethanethiol-H p -zeolite → H p -zeolite + ethene + H 2 S, has been investigated computationally with the use of ab initio, density functional theory (DFT) and MM methods. The investigation has been carried out by employing two model zeolite clusters, each including one hydroxyl Brønsted acidic site (BAS). The first model, denoted 20T, has been studied with the help of the two-layered ONIOM2 (M06-2X/6-31 + G(d,p):UFF) methodology and the second one denoted 38T, has been investigated using the three-layered ONIOM3 (M06-2X/6-31 + G(d,p):HF:UFF) approach. The calculations using both models show that the reaction mechanism involves two competing channels, a direct t2 type dehydrosulfidation (DHS) channel, and a stepwise Sw2 type pathway through the intermediate formation of an alkoxy species. The detailed examination of the two pathways, i.e., the direct mechanism and the stepwise mechanism, indicate that the latter is strongly favored over the direct t2 type mechanism. Finally, the consistency of the results from both methodologies suggests that the ONIOM approach yields an accurate and practical method to study the degradation mechanism of sulfur containing compounds on acidic zeolite surface. [ABSTRACT FROM AUTHOR]

Two kinds of structures are identified for the [CH 2 XNO 2 ·H 2 O] (X = H, F, Cl, Br, I) clusters, using ab initio and DFT computational techniques. The configurations of the resulting water complexes arise from the two different ways of possible hydrogen bonding interaction. Both types of complexes present cyclic geometries formed through either the interaction of a methylic H with the O atom of the water molecule, type (a), or via the symmetric coupling of each H atom of the water molecule with each O atom of the nitro group, type (b). The examination of the stereochemistry of the complexes shows a dependence on the halogen atom involved. The type (a) complexes are more stable and assumingly, those are primarily involved in the degradation mechanism of halogenated nitromethanes in water solvated surroundings. [ABSTRACT FROM AUTHOR]

The international experimental campaign Hygroscopic Aerosols to Cloud Droplets (HygrA-CD), organized in the Greater Athens Area (GAA), Greece from 15 May to 22 June 2014, aimed to study the physico-chemical properties of aerosols and their impact on the formation of clouds in the convective Planetary Boundary Layer (PBL). We found that under continental (W-NW-N) and Etesian (NE) synoptic wind flow and with a deep moist PBL (~ 2–2.5 km height), mixed hygroscopic (anthropogenic, biomass burning and marine) particles arrive over the GAA, and contribute to the formation of convective non-precipitating PBL clouds (of ~ 16–20 μm mean diameter) with vertical extent up to 500 m. Under these conditions, high updraft velocities (1–2 m s − 1 ) and cloud condensation nuclei (CCN) concentrations (~ 2000 cm − 3 at 1% supersaturation), generated clouds with an estimated cloud droplet number of ~ 600 cm − 3 . Under Saharan wind flow conditions (S-SW) a shallow PBL (< 1–1.2 km height) develops, leading to much higher CCN concentrations (~ 3500–5000 cm − 3 at 1% supersaturation) near the ground; updraft velocities, however, were significantly lower, with an estimated maximum cloud droplet number of ~ 200 cm − 3 and without observed significant PBL cloud formation. The largest contribution to cloud droplet number variance is attributed to the updraft velocity variability, followed by variances in aerosol number concentration. [ABSTRACT FROM AUTHOR]

The details of the bromine atom transfer mechanism from an ethyl bromide molecule to an O-bonded alkyl group, attached to the FAU zeolite wall, were elucidated, by means of Quantum Mechanical and Molecular Mechanical (QM/MM) calculations. The investigation of this mechanism has been established on the 84T model cluster of faujasite zeolite with the help of the ONIOM approach, utilizing three-layer ONIOM3(B3LYP/6-31 + G(d,p):HF/6-31G:UFF), ONIOM3(M06-2X/6-31 + G(d,p):HF/6-31G:UFF) and ONIOM3(MP2(full)/6-31 + G(d,p):HF/6-31G:UFF) schemes. Our results indicate that the reaction proceeds via a ring structure formation path, where the ethyl bromide molecule is strongly attracted to both the alkyl group and the nearby Si bridging lattice O atom. Interaction energies for the O-bonded alkyl (ethyl or isopropyl) group linked to an ethyl bromide molecule in a FAU pore according to the ONIOM3(MP2(full)/6-31+G(d,p):HF/6-31G:UFF) calculation are approximately −18.3 and −19.3 kcal mol −1 , respectively. In addition, at the same level of theory, the bromine atom shift from the ethyl bromide molecule to the adjacent O-bonded ethyl or isopropyl group, forming a new alkyl bromide and a new ethyl radical, are characterized by an activation barrier of 25.1 and 17.9 kcal mol −1 , respectively, relative to the reagent complex. [ABSTRACT FROM AUTHOR]

A coordinated experimental campaign aiming to study the aerosol optical, size and mass properties was organized in September 2012, in selected sites in Greece and Romania. It was based on the synergy of lidar and sunphotometers. In this paper we focus on a specific campaign period (23–24 September), where mixed type aerosols (Saharan dust, biomass burning and continental) were confined from the Planetary Boundary Layer (PBL) up to 4–4.5 km height. Hourly mean linear depolarization and lidar ratio values were measured inside the dust layers, ranging from 13 to 29 and from 44 to 65 sr, respectively, depending on their mixing status and the corresponding air mass pathways over Greece and Romania. During this event the columnar Aerosol Optical Depth (AOD) values ranged from 0.13 to 0.26 at 532 nm. The Lidar/Radiometer Inversion Code (LIRIC) and the Polarization Lidar Photometer Networking (POLIPHON) codes were used and inter-compared with regards to the retrieved aerosol (fine and coarse spherical/spheroid) mass concentrations, showing that LIRIC generally overestimates the aerosol mass concentrations, in the case of spherical particles. For non-spherical particles the difference in the retrieved mass concentration profiles from these two codes remained smaller than ± 20%. POLIPHON retrievals showed that the non-spherical particles reached concentrations of the order of 100–140 μg/m 3 over Romania compared to 50–75 μg/m 3 over Greece. Finally, the Dust Regional Atmospheric Model (DREAM) model was used to simulate the dust concentrations over the South-Eastern Europe. [ABSTRACT FROM AUTHOR]

Objectives: This study sought to evaluate the incidence, correlates, and clinical implications of periprocedural myocardial injury (PMI) during percutaneous coronary intervention (PCI) of chronic total occlusions (CTO). Background: The risk of PMI during CTO PCI may be underestimated because systematic cardiac biomarker measurement was not performed in published studies. Methods: We retrospectively examined PMI among 325 consecutive CTO PCI performed at our institution between 2005 and 2012. Creatine kinase-myocardial band fraction and troponin were measured before PCI and 8 to 12 h and 18 to 24 h after PCI in all patients. PMI was defined as creatine kinase-myocardial band increase ≥3× the upper limit of normal. Major adverse cardiac events during mid-term follow-up were evaluated. Results: Mean age was 64 ± 8 years. The retrograde approach was used in 26.8% of all procedures. The technical and procedural success was 77.8% and 76.6%, respectively. PMI occurred in 28 patients (8.6%, 95% confidence intervals: 5.8% to 12.2%), with symptomatic ischemia in 7 of those patients. The incidence of PMI was higher in patients treated with the retrograde than the antegrade approach (13.8% vs. 6.7%, p = 0.04). During a median follow-up of 2.3 years, compared with patients without PMI, those with PMI had a higher incidence of major adverse cardiac events (hazard ratio [HR]: 2.25, p = 0.006). Patients with only asymptomatic PMI also had a higher incidence of major adverse cardiac events on follow-up (HR: 2.26, p = 0.013). Conclusions: Systematic measurement of cardiac biomarkers post–CTO PCI demonstrates that PMI occurs in 8.6% of patients, is more common with the retrograde approach, and is associated with worse subsequent clinical outcomes during mid-term follow-up. [Copyright &y& Elsevier]

Objectives: This study sought to compare and contrast use and radiation exposure using radial versus femoral access during cardiac catheterization of patients who had previously undergone coronary artery bypass graft (CABG) surgery. Background: Limited information is available on the relative merits of radial compared with femoral access for cardiac catheterization in patients who had previously undergone CABG surgery. Methods: Consecutive patients (N = 128) having previously undergone CABG surgery and referred for cardiac catheterization were randomized to radial or femoral access. The primary study endpoint was contrast volume. Secondary endpoints included fluoroscopy time, procedure time, patient and operator radiation exposure, vascular complications, and major adverse cardiac events. Analyses were by intention-to-treat. Results: Compared with femoral access, diagnostic coronary angiography via radial access was associated with a higher mean contrast volume (142 ± 39 ml vs. 171 ± 72 ml, p < 0.01), longer procedure time (21.9 ± 6.8 min vs. 34.2 ± 14.7 min, p < 0.01), greater patient air kerma (kinetic energy released per unit mass) radiation exposure (1.08 ± 0.54 Gy vs. 1.29 ± 0.67 Gy, p = 0.06), and higher operator radiation dose (first operator: 1.3 ± 1.0 mrem vs. 2.6 ± 1.7 mrem, p < 0.01; second operator 0.8 ± 1.1 mrem vs. 1.8 ± 2.1 mrem, p = 0.01). Fewer patients underwent ad hoc percutaneous coronary intervention (PCI) in the radial group (37.5% vs. 46.9%, p = 0.28) and radial PCI procedures were less complex. The incidences of the primary and secondary endpoints was similar with femoral and radial access among PCI patients. Access crossover was higher in the radial group (17.2% vs. 0.0%, p < 0.01) and vascular access site complications were similar in both groups (3.1%). Conclusions: In patients who had previously undergone CABG surgery, transradial diagnostic coronary angiography was associated with greater contrast use, longer procedure time, and greater access crossover and operator radiation exposure compared with transfemoral angiography. (RADIAL Versus Femoral Access for Coronary Artery Bypass Graft Angiography and Intervention [RADIAL-CABG] Trial; NCT01446263). [Copyright &y& Elsevier]

Highlights: [•] Computational study of the water catalyzed ClCH2NO2 +OH reaction. [•] Transition state determination in water free environment. [•] Reaction mechanism without and with the coordination of one water molecule. [ABSTRACT FROM AUTHOR]

Objectives: This study sought to examine the contemporary outcomes of retrograde chronic total occlusion (CTO) interventions among 3 experienced U.S. centers. Background: The retrograde approach, pioneered and developed in Japan, has revolutionized the treatment of coronary CTO, yet limited information exists on procedural efficacy, safety, and reproducibility of outcomes in other settings. Methods: Between 2006 and 2011, 462 consecutive retrograde CTO interventions were performed at 3 U.S. institutions. Patient characteristics, procedural outcomes, and in-hospital clinical events were ascertained. Results: Mean patient age was 65 ± 9.7 years, 84% were men, and 50% had prior coronary artery bypass surgery. The CTO target vessel was the right coronary artery (66%), circumflex (18%), left anterior descending artery (15.5%), and left main artery or bypass graft (0.5%). The retrograde approach was used as the primary method in 46% of cases and after failed antegrade recanalization in 54%. Retrograde collateral vessels were septal (68%), epicardial (24%), and bypass grafts (8%). Technical and procedural success was 81.4% (n = 376) and 79.4% (n = 367), respectively. The mean contrast volume and fluoroscopy time were 345 ± 177 ml and 61 ± 40 min, respectively. A major complication occurred in 12 patients (2.6%). In multivariable analysis, years since initiation of retrograde CTO percutaneous coronary intervention (PCI) at each center, female sex, and ejection fraction ≥40% were associated with higher technical success. Conclusions: Among selected U.S. programs, retrograde CTO PCI is often performed in patients with prior coronary bypass graft surgery and is associated with favorably high success and low complication rates. [ABSTRACT FROM AUTHOR]

Abstract: The vertical extension and the optical properties of aged ash layers advected from the Eyjafjallajökull volcanic eruption over the Eastern Mediterranean (Greece and Turkey) are presented for the period May 10–21, 2010. Raman lidar observations performed at three stations of EARLINET (Athens, Thessaloniki and Istanbul), provided clear ash signatures within certain layers, although ash was sometimes mixed with mineral dust advected from the Saharan region. AERONET columnar measurements did not indicate the presence of ash over the area for that period, although they did for the dust particles. This was further investigated and confirmed by simulations of the ash trajectories by the FLEXPART model and the BSC-DREAM8b dust model. Good agreement was found between simulated and observed geometrical characteristics of the ash and dust layers, respectively. Ash particles were observed over the lidar stations after 6–7-days transport from the volcanic source at height ranges between approximately 1.5 and 6 km. Mean ash particle layer thickness ranged between 1.5 and 2.5 km and the corresponding aerosol optical depth (AOD) was of the order of 0.12–0.06 at 355 nm and of 0.04–0.05 at 532 nm. Inside the ash layers, the lidar ratios (LR) ranged between 55 and 67 sr at 355 nm and 76–89 sr at 532 nm, while the particle linear depolarization ratio ranged between 10 and 25%. [Copyright &y& Elsevier]

Abstract: In this work an analysis of continuous Differential Optical Absorption Spectroscopy (DOAS) measurements of primary and secondary air pollutants (SO2, NO2 and O3) in the Athens basin is performed combined with Differential Absorption Lidar (DIAL) vertical ozone measurements obtained inside the Planetary Boundary Layer (PBL) and the lower free troposphere. The measurements took place during the period May 2005–February 2007, at the National Technical University of Athens Campus (200m above sea level (asl.), 37.96°N, 23.78°E). The SO2 and NO2 DOAS measurements showed maximum 1-hour mean values (around 20μg/m3 and 74μg/m3, respectively) in winter and did not exceed the current European Union (EU) air quality standards (European Council Directive 2008/50/EC), in contrast to ozone, which shows its maximum (around 128μg/m3) in summer and frequently exceeds the EU standard for human health protection (120μg/m3). If the measurements are classified according to the two most frequent flow-patterns of the air masses in the Athens basin (northern–southern circulation), it is observed that in general the atmospheric concentrations of all measured pollutants including ozone are higher when the southern circulation occurs, in comparison to the corresponding values under the northern circulation. The vertical ozone profiles obtained by DIAL were also higher under the southern circulation. During the summer months a mean difference (between the southern-northern circulations) of the order of 15–20μg/m3, maximized at the 0.9–1.1km and 1.7–1.8km height, was observed within the PBL. It was also observed that the summer surface ozone levels remained relatively high (around 80–110μg/m3) even during strong northerly winds, verifying the high levels of rural surface ozone in the surrounding area reported by previous studies. [Copyright &y& Elsevier]

Abstract: The interaction of ethyl chloride with two model zeolite clusters, each including one hydroxyl Brönsted acid site, has been investigated using density functional theory (DFT) and MM methods. The first model contains three tetrahedral zeolite units (T3) and has been studied at the B3LYP(full) level in combination with the 6-311G(d,p) and the cc-pVTZ basis sets. The second model is represented by a 12-membered ring (T12) and has been investigated with the help of the two-layered ONIOM (B3LYP/6-311G(d,p): UFF) methodology. The reliability of the latter method was checked against the optimization of the adsorption complex in the T12 cluster at the B3LYP(full)/6-311G(d,p) level. The calculations show that the reaction mechanism involves two competing channels, a direct E2 type dehydrohalogenation channel and a SN2 type pathway through the intermediate formation of an alkoxy species, the latter channel presenting a lower activation energy than the former. The overall potential energy surface becomes more attractive when using the more realistic T12 framework and the calculated difference in the activation energy barrier heights between the two channels increases from ∼1kcalmol−1 in the T3 framework to ∼4kcalmol−1 in T12 model. Finally, the effect of zeolite acidity on the reaction barrier is investigated by increasing the length of a terminal Si–H bond in the T3 model. The results indicate the distinct reduction of the activation barrier as the acidity increases. [ABSTRACT FROM AUTHOR]

Abstract: The structural, frequency and energy characteristics and the nature of bonding of the molecular complexes between N-methyl imidazoline-2-thione (methimazole) and the related saturated analog, N-methyl imidazolidine-2-thione and the dihalogens IY (Y=Cl, Br, I) are investigated using quantum mechanical computational techniques. Two types of stereoisomeric energy minima have been studied for each parent thioamide system. Both present a collinear S–I–Y geometry and are distinguished by the geometry of the dihalogen IY molecular axis located at either a planar or a perpendicular arrangement with respect to the imidazolethione, NCS, plane. The planar conformations have been found to be more stable than the perpendicular ones, since they allow a more favourable geometry for an additional interaction between the iodine atom and the amidic H. The results reveal interesting correlations of various structural and frequency features like the C–S and S–I bonding distances and the N–H stretching frequency shifts with the enthalpy of complexation, the electron donor–acceptor capacity of the dihalogen and the electronegativity of the Y atom and the strength of the interaction between the amidic hydrogen and the inner I. [Copyright &y& Elsevier]

Abstract: Ab initio calculations have been performed for both H-atom and Cl-atom abstraction reactions by the hydroxyl radical. Geometry optimization and vibrational frequencies analysis were performed for reactants, transition state and products at the MP2(full)/cc-pVTZ level of theory. On the basis of the ab initio data, the rate constants have been deduced over a wide temperature range, 200–2000 K, using conventional transition state theory, including Wigner tunneling correction and the hindered rotor approximation. Calculated transition state rate constants with Wigner tunneling correction are in good agreement with experimental results. The tunneling contribution becomes important at ambient temperatures, resulting in the exhibited non-Arrhenius behavior of the rate constant. [Copyright &y& Elsevier]

The equilibrium structures, vibrational spectra and relative energetics of (INO3) isomers have been investigated at the B3LYP, MP2 and CCSD(T) levels of theory, using the LANL2DZ methodology augmented with d and f polarization functions. The results indicate that iodine nitrate, IONO2, is by far the lowest energy structure while the cis-perp and trans-perp iodine peroxy nitrites, IOONO, are less stable by 31.6 and 34.2 kcalmol−1, respectively, at the CCSD(T) level. The third isomer, OIONO, is found to be a bound minimum in both cis-perp and trans-perp conformations. [Copyright &y& Elsevier]

Two different effective-core-potential methodologies, augmented with extra polarization functions are used at the MP2 level of theory to investigate the isomers of I-containing peroxides of the type XOOI, XIO2, IXO2, XOIO and IOXO (X=Cl, Br, I). The reliability of the results is checked against the all-electron calculations of Misra and Marshall [J. Phys. Chem. A, 102 (1998) 9056] for the IOOI family. Contrary to what has been well established for the chlorine and bromine analogs, the present study confirms the interesting observation that the I-containing peroxide isomers, XOOI, are not the most stable structures in each subfamily. [Copyright &y& Elsevier]

Quantum mechanical electronic structure calculations were carried out to determine equilibrium geometries, energetics and normal mode frequencies of stationary points along the minimum energy reaction path for the reaction of methyl radicals with bromine molecules. The results are used to calculate the reactive cross-section as a function of the initial energy and the rate coefficient at different temperatures, employing both extended RRKM theory and quasi-classical trajectory techniques. Both methods agree fairly well with the experimental measurements and describe sufficiently well the slight decline in reactivity with increasing temperature, which is observed experimentally. [Copyright &y& Elsevier]

Quantum mechanical and RRKM calculations are carried out to study the potential energy surface and the kinetics for the six most important decomposition channels of methyl hypobromite (CH3OBr). Optimized geometries, vibrational frequencies, and relative energies have been obtained for the various stationary points. The O–Br bond scission to CH3O+Br products and the 1,2 elimination pathway leading to HCHO+HBr appear to be the most important dissociation channels. Analogous paths from the isomeric BrCH2OH are also examined. The calculations are compared with the results for the other two similar systems, CH3OF and CH3OCl. [Copyright &y& Elsevier]

Two different effective-core-potential methodologies, augmented by extra polarization functions were used to investigate a number of iodine triatomics of the type XOI, XIO and IXO (X = Cl, Br, I). The procedures were tested first on the well-studied ClOCl, BrOBr, ClOBr and IOI systems and they were shown to reproduce the full-electron calculation results with reasonable consistency. The results exhibit the same tendencies as the corresponding Cl and Br analogues and produce the greater stability for the isomer with the least electronegative atom in the middle. [Copyright &y& Elsevier]

The PANhellenic infrastructure for Atmospheric Composition and climate change (PANACEA) campaign took place in July 2019, to assess the presence of aerosols both in situ and at different heights, in selected cities of Greece suffering from high air pollution levels. One of these sites was the city of Volos (39.21° N., 22.57° E). Vertical profiles of the aerosol backscatter coefficient (b aer) and the particle linear depolarization ratio (δ p) of maritime polluted, urban, smoke and dust mixtures were measured during using the mobile depolarization Aerosol lIdAr System (AIAS). 42 aerosol layers were characterized, out of which 40% were of urban origin, 26% of smoke origin, 21% maritime polluted aerosol layers and 12% dust mixtures. The maritime polluted and urban aerosols showed a mean δ p value at 532 nm of 4 ± 1%, within a range of 2–6% and 2–5%, respectively. The smoke aerosols showed a mean δ p value of 6 ± 1%, within a range of 3–9%, while the dust mixtures showed a mean δ p of 20 ± 4%, ranging from 13 to 29%. Finally, the majority of these layers were observed above 250 up to 2000 m height asl., although the dust mixtures reached 3000 m height asl. • Vertical profiles of the b aer and the δ p of maritime polluted, urban, smoke and dust mixture aerosols. • The maritime polluted and urban aerosols showed a mean δ p at 532 nm of 4±1 %, within a range of 2-6 % and 2-5 %, respectively. • The smoke aerosols showed a mean δ p value of 6±1 %, within a range of 3-9 %. • The dust mixtures showed a mean δ p of 20±4 %, ranging from 13 to 29 %. [ABSTRACT FROM AUTHOR]

Abstract: Background: In the absence of radiopaque graft markers, engaging unusual saphenous vein grafts can be challenging. Methods: We describe a case in which a saphenous vein graft to the first obtuse marginal branch could not be located, in spite of performing aortic root angiography. The saphenous vein graft was wired retrogradely through the native left main and the wire was advanced into the aorta, serving as a marker of the abnormally low origin of the graft that was successfully engaged with a multipurpose catheter. Results: The guidewire was successfully advanced retrogradely through the SVG into the aorta, allowing localization of the SVG ostium that was sewn in an unusually low location. Conclusions: Retrograde SVG wiring is an advanced, “last resort” technique for identifying the ostium and cannulating unusual aortocoronary bypass grafts. [Copyright &y& Elsevier]

• Computational studies on the reactions of the radical CF 3 OCH 2 OO with HO 2 and NO in the gas-phase are performed. • Both reactions are shown to proceed through reaction intermediates. CF 3 OCH 2 OO + HO 2 yields CF 3 OCH 2 OOH through the triplet surface. CF 3 OCH 2 OO + NO leads to CF 3 OCH 2 O and NO 2 which partly recombine towards CF 3 OCH 2 NO 2. • The comparison with the plain methyl systems CF 3 OCH 2 OO + HO 2 , NO shows a lowering of the energy profile by 2–3 kcal/mol, due to the inductive effect of the F atoms. Computational studies on the reactions of the peroxy radical, CF 3 OCH 2 O 2 , with the species HO 2 and NO in the gas-phase are carried out, using ab initio and density functional theory methods. Formation of CF 3 OCH 2 OOH, through the attractive triplet state, is shown to be the dominant pathway in the reaction with HO 2 . The coupling with NO leads primarily to CF 3 OCH 2 O and NO 2 through the decomposition of the association nitrite minimum CF 3 OCH 2 OONO. The nitrate adduct CF 3 OCH 2 ONO 2 , a sink byproduct, may be produced in a two-step mechanism by the partial recombination of CF 3 OCH 2 O and NO 2 . The results are discussed in comparison with the general mechanism of the reactions of the organic peroxy radicals ROO with HO 2 and NO. Also the present systems are shown to exhibit interesting correlations with regard to the reactivity of the peroxy radical, CH 3 OCH 2 O 2 , reflecting the inductive effect of the fluorine atoms in the methoxy methyl group. [ABSTRACT FROM AUTHOR]

PURPOSE: To assess the effects of intravitreal ranibizumab injection in patients affected by pigment epithelial detachment associated with occult subfoveal choroidal neovascularization. DESIGN: Prospective, interventional case series. METHODS: Participants: Forty eyes of 40 patients were considered for the purpose of the study. Consecutive patients were recruited for a 24-month study. All patients underwent a complete ophthalmic examination, including best-corrected visual acuity on Early Treatment Diabetic Retinopathy Study (ETDRS) charts. After a 3-monthly loading phase, further intravitreal ranibizumab injections were administered on the basis of detection of any type of fluid on optical coherence tomography. Primary outcome measures: Changes in mean best-corrected visual acuity at 12 and 24 months and the proportion of eyes losing fewer than 15 letters (corresponding to 3 ETDRS lines) from baseline visual acuity. Secondary outcome measures: Changes in central macular thickness on optical coherence tomography and variation in mean area of the entire lesion. RESULTS: Forty patients were included. Mean bestcorrected visual acuity decreased from 20/66 (58 ETDRS letters) to 20/83 (53 letters) at 12 months and 20/112 (489 ETDRS letters) at 24 months (P [ .003). Eighty percent and 67.5% of eyes lost fewer than 3 lines at 12 and 24 months, respectively. Mean central macular thickness passed from 545 mm to 428 mm at 12 months and 426 mm at 24 months. Mean lesion area changed from 6826 mm2 to 6312 mm2 at 12 months and 6010 mm2 at 24 months. CONCLUSIONS: The treatment of pigment epithelial detachment associated with occult subfoveal choroidal neovascularization with intravitreal ranibizumab injection after a 3-monthly loading phase and pro re nata strategy can lead to partial results over a 24-month follow-up. Further investigations are warranted to establish the best therapeutic approach to this disease. [ABSTRACT FROM AUTHOR]

We aimed to examine whether an association exists between the presence and extent of coronary lipid core plaques (LCPs) detected by near-infrared spectroscopy (NIRS) performed before percutaneous coronary intervention (PCI) with postprocedural myocardial infarction (MI). NIRS was performed in the native coronary arteries of 30 patients before PCI. Angular extent of LCP, lesion segment lipid core burden index, and block chemogram were evaluated. Cardiac biomarkers were measured before and 16 to 24 hours after PCI to determine occurrence of postprocedural MI. Mean number of 2-mm yellow blocks within the stented lesion was 1.4 ± 2.1 and mean lesion lipid core burden index was 110.3 ± 99. Using a definition of creatine kinase-MB >1 time upper limit of normal (ULN), >2 times ULN, and >3 times ULN, MI after PCI occurred in 23%, 13%, and 10% of patients, respectively. Compared to patients who did not have MI after PCI, those who did had similar clinical characteristics but received more stents and had more blocks within the stented lesion. Creatine kinase-MB increase >3 times ULN was observed in 27% of patients with ≥1 yellow block versus in none of the patients without a yellow block within the stented lesion (p = 0.02). In conclusion, PCI of LCP-positive lesions as assessed by NIRS is associated with increased risk for MI after PCI. NIRS may allow lesion-specific risk stratification before PCI and optimization of PCI strategies for myocardial injury risk minimization. [ABSTRACT FROM AUTHOR]

Objective: To confirm the beneficial effect of endometrial coculture in patients with repeated failures with assisted reproductive techniques (ART). Design: Patients with previous failures were offered a repetition of ART in conjunction with autologous endometrial coculture. Setting: Private fertility center. Patient(s): Sixty-eight couples who had attempted 92 cycles of IVF or intracytoplasmic sperm injection without obtaining an evolutive pregnancy. Intervention(s): Patients repeated one cycle of ART with concomitant endometrial coculture of their embryos. Main Outcome Measures(s): Comparative pregnancy and delivery rates in conventional ART cycles vs. cycles with autologous endometrial coculture. Result(s): In the previous 92 cycles (146 ETs, fresh plus frozen) only 8 pregnancies were initiated, and all ended in spontaneous abortion. Upon repeating 68 cycles (76 ETs) using coculture, 39 pregnancies were obtained, of which 19 resulted in live births, 10 are ongoing evolutive pregnancies, and 10 ended in spontaneous abortions. Conclusion(s): These results confirm the usefulness of autologous endometrial coculture for the treatment of patients with repeated implantation failure. [Copyright &y& Elsevier]

Abstract: Ab initio calculations were conducted for both reaction pathways of the CH3Br and OH system. Geometry optimization and vibrational frequencies analysis were performed for reactants, pre-reaction complex, transition states, post-reaction complex and products at the MP2(full)/6-311+G(d,p), MP2(full)/6-311+G(3df,2pd) and MP2(full)/cc-pVTZ levels of theory. Energetic results were further refined by CCSD(T,full) calculations, using optimized geometric parameters of the MP2(full)/cc-pVTZ level, i.e., CCSD(T,full)/cc-pVTZ//MP2(full)/cc-pVTZ. Based on MP2(full)/cc-pVTZ and CCSD(T,full)/cc-pVTZ//MP2(full)/cc-pVTZ data, rate constants were deduced in the 200–2000K temperature range, using conventional transition state theory and Wigner tunneling correction. Calculated rate constants, including tunneling corrections, were found to be in excellent agreement with experimental results. [Copyright &y& Elsevier]