Impact of a carotid stenosis on cardiac surgery: marker more than risk factor

A concurrent carotid and cardiac disease is the paradigmatic expression of a multidistrictal vasculopathy related to an atherosclerotic burden, that shares the same risk factors and onset pathophysiological mechanisms. The absolute incidence of a stroke after open heart surgery (OHS) is about 2%, higher in case of combined cardiac procedures, with a negative prognostic impact in terms of in-hospital mortality and neurological morbidity. Heterogenous and interlinked risk factors contribute to the genesis of cerebral injuries after OHS outlining patient general features, vascular risk parameters and severity indeces of cardiac disease; a model stroke for patients undergoing cardiac surgery may be helpful so as to identify subsets of patients at high risk and select the most appropriate strategy. A critical carotid stenosis should be contextualized not as the Romadirect cause of stroke, but as a risk marker of high grade atherosclerotic systemic disease, predicting a potential severe aortic or intracerebral vessel disease and leading to recognize and study carefully these multivascular patients before operation. The idea of carotid plaque as active embolic source is valid only in case of vulnerable plaques in relation to the potential detachment of particulate material. Until now the neurological status, in accordance with symptomatic or asymptomatic carotid stenosis, has markedly influenced the operation timing and the choice of the surgical strategy. Except for special circumstances, we generally suggest a 'reverse staged' surgical strategy with cardiac surgery before carotid timing in elective patients recommending strongly a pharmacological neuroprotection relied on the administration of Sodium Thiopentone. Most of carotid stenosis in patients undergoing OHS is asymptomatic and doesn't represent a proven independent risk factor for postoperative stroke; indeed, we advocate that synchronous surgical treatment of both carotid and cardiac lesions is burdened from higher perioperative mortality and stroke rates rightfully unjustifiable according to potential benefits.

Skin ulcers complicating sickle cell disease: an interlinked reparative model

Skin ulcers represent a common complication of sickle cell disease, especially in homozygous forms, with multifactorial pathogenetic mechanisms and frequent location at lower extremities; more specifically perimalleolar areas are favourite location because of a chronic microvascular disturbance and capillary stasis in a district with low fatty tissue. Chronicization and recurrence of unhealable lesions significantly have a high impact on quality of life of these patients in terms of pain management and psycho-physical dysfuncRomation. When we deal with a chronic ulcer, as it often happens in patients affected by hemoglobinopathies, the key-point is to make the skin lesion healable and vital by reactivating blocked repair process. Although it's controversial topic, patterns of patients with higher HbF concentrations might be more protective in accordance with reduced HbS polymerization; indeed, clinical features of ulcer represent the best predictors suggesting the correct strategy to achieve a good final outcome. Hereafter we report the case of a young woman with skin complications secondary to drepanocytosis, in which an interlinked reparative model consisting of surgery and advanced medications in addition to an adequate transfusional support, especially in earlier phases, has allowed to achieve clinical success after several years of care failure.

Rippling of graphitic surfaces: a comparison between few-layer graphene and HOPG

The surface structure of Few-Layer Graphene (FLG) epitaxially grown on the C-face of SiC has been investigated by TM-AFM in ambient air and upon interaction with dilute aqueous solutions of bio-organic molecules (l-methionine and dimethyl sulfoxide, DMSO). Before interaction with molecular solutions, we observe nicely ordered, three-fold oriented rippled domains, with a 4.7 ± 0.2 nm periodicity (small periodicity, SP) and a peak-to-valley distance in the range 0.1-0.2 nm. Upon mild interaction with the molecular solution, the ripple periodicity "relaxes" to 6.2 ± 0.2 nm (large periodicity, LP), while the peak-to-valley height increases to 0.2-0.3 nm. When additional energy is transferred to the system through sonication in solution, graphene planes are peeled off, as shown by quantitative analysis of Raman spectroscopy and X-ray photoelectron spectroscopy which indicate a neat reduction of thickness. Upon exfoliation rippled domains are no longer observed. In comparative experiments on cleaved HOPG, we could not observe ripples on pristine samples in ambient air, while LP ripples develop upon interaction with the molecular solutions. Recent literature on similar systems is not univocal regarding the interpretation of rippling. The ensemble of our comparative observations on FLG and HOPG can be hardly rationalized solely on the basis of the surface assembly of molecules, either organic molecules coming from the solution or adventitious species. We propose to consider rippling as the manifestation of the free-energy minimization of quasi-2D layers, eventually affected by factors such as interplanar stacking, and interactions with molecules and/or with the AFM tip.

Binding geometry of hydrogen-bonded chain motif in self-assembled gratings and layers on Ag(111)

Upon adsorption on the (111) facet of Ag, 4-[trans-2-(pyrid-4-yl-vinyl)] benzoic acid (PVBA) self-assembles into a highly ordered, chiral twin chain structure at submonolayer coverages with domains that can extend for micrometers in one dimension. Using polarization-dependent measurements of C and N K-shell excitations in near-edge X-ray absorption fine structure (NEXAFS) spectra, we determine the binding geometry of single PVBA molecules within this unique ensemble for both low and high coverage regimes. At submonolayer coverage, the molecule is twisted to facilitate the formation of hydrogen bonds. The gas-phase planarity is gradually recovered as the coverage is increased, with complete planarity coinciding with loss of order in the overlayer. Thermal treatment of the PVBA film results in deprotonation of the carboxyl tail of the molecule, but despite the suppression of the stabilizing hydrogen-bonds, the overlayer remains ordered.

Tracking the excitation dynamics in the Mn:Ge(111) metallic interface by resonant electron spectroscopy

Resonant photoemission from the valence band of a (√3 × √3)R30° reconstructed Mn:Ge(111) metallic interface has been carefully analyzed with the aim to track the transition from resonant Raman to normal Auger emission. The transition energy has been compared with the Mn 2p binding energy, as well as with the Mn L(3) absorption edge energy. Close similarities emerge with respect to the case of elemental Mn thin films, suggesting that the excitation dynamics is dominated by the electronic properties of Mn 3d states, in spite of the bonding with Ge atoms. The switching from the resonant Raman Auger (RRAS) to the normal Auger regime is found about 2 eV below the Mn L(3) absorption edge. A change of the lineshape due to the transition from an overall N - 1 electron final state (RRAS channel) to an N - 2 electron final state (normal Auger channel) is evidenced by the analysis of the experimental data, which also allowed the ratio to be tracked between charge delocalization and core-hole time scales as the photon energy is tuned across the Mn L(3) edge.

Intrinsic nature of the excess electron distribution at the TiO2(110) surface

The gap state that appears upon reduction of TiO2 plays a key role in many of titania's interesting properties but its origin and spatial localization have remained unclear. In the present work, the TiO2(110) surface is reduced in a chemically controlled way by sodium adsorption. By means of resonant photoelectron diffraction, excess electrons are shown to be distributed mainly on subsurface Ti sites strikingly similar to the defective TiO2(110) surface, while any significant contribution from interstitial Ti ions is discarded. In agreement with first principles calculations, these findings demonstrate that the distribution of the band gap charge is an intrinsic property of TiO2(110), independent of the way excess electrons are produced.

Relating energy level alignment and amine-linked single molecule junction conductance

Using photoemission spectroscopy, we determine the relationship between electronic energy level alignment at a metal-molecule interface and single-molecule junction transport data. We measure the position of the highest occupied molecular orbital (HOMO) relative to the Au metal Fermi level for three 1,4-benzenediamine derivatives on Au(111) and Au(110) with ultraviolet and resonant X-ray photoemission spectroscopy. We compare these results to scanning tunnelling microscope-based break-junction measurements of single molecule conductance and to first-principles calculations. We find that the energy difference between the HOMO and Fermi level for the three molecules adsorbed on Au(111) correlate well with changes in conductance and agree well with quasiparticle energies computed from first-principles calculations incorporating self-energy corrections. On the Au(110) that presents Au atoms with lower-coordination, critical in break-junction conductance measurements, we see that the HOMO level shifts further from the Fermi level. These results provide the first direct comparison of spectroscopic energy level alignment measurements with single molecule junction transport data.

Analysis of Single Nucleotide Polymorphisms (SNPs) of the small-conductance calcium activated potassium channel (SK3) gene as genetic modifier of the cardiac phenotype in myotonic dystrophy type 1 patients

Myotonic dystrophy type 1 (DM1) is the most frequently inherited neuromuscular disease in adults. It is a multisystemic disorder with major cardiac involvement most commonly represented by first-degree atrioventricular heart block (AVB), followed by different degrees of bundle-branch and intraventricular blocks In search for candidate genes, modifiers of the AVB phenotype in DM1, the expression of the small-conductance calcium activated potassium channel (SK3) gene was analysed in muscle biopsies from DM1 patients. The association between SK3 polymorphisms and the AVB phenotype was then studied analyzing 40 DM1 patients with AVB and 40 age-matched DM1 affected individuals with no ECG abnormalities. [CTG]n repeat length and cardiac clinical picture were also assessed for correlation. QRT-PCR experiments showed an over-expression of the SK3 transcript in DM1 muscle biopsies compared to healthy controls. However, no statistical association between the AVB phenotype and either the [CTG]n expansion length or the presence of specific SNPs in the SK3 gene were detected. These findings suggest that modifier genes, other than SK3, should be identified in order to explain the cardiac phenotypic variability among DM1 patients.

Defect states at the TiO2(110) surface probed by resonant photoelectron diffraction

The charge distribution of the defect states at the reduced TiO(2)(110) surface is studied via a new method, the resonant photoelectron diffraction. The diffraction pattern from the defect state, excited at the Ti-2p-3d resonance, is analyzed in the forward scattering approach and on the basis of multiple scattering calculations. The defect charge is found to be shared by several surface and subsurface Ti sites with the dominant contribution on a specific subsurface site in agreement with density functional theory calculations.

Structure of a CH3S monolayer on Au(111) solved by the interplay between molecular dynamics calculations and diffraction measurements

We have investigated the controversy surrounding the (sqrt[3] x sqrt[3]) R30 degrees structure of self-assembled monolayers of methylthiolate on Au(111) by first principles molecular dynamics simulations, energy and angle resolved photoelectron diffraction, and grazing incidence x-ray diffraction. Our simulations find a dynamic equilibrium between bridge site adsorption and a novel structure where 2 CH3S radicals are bound to an Au adatom that has been lifted from the gold substrate. As a result, the interface is characterized by a large atomic roughness with both adatoms and vacancies. This result is confirmed by extensive photoelectron and grazing incidence x-ray diffraction measurements.

Electronic properties of a pure and sodium-doped C70 single layer adsorbed on Al polycrystalline surface

Core level and valence band photoemission measurements combined with near edge x-ray absorption fine structure measurements were performed on a single C(70) layer adsorbed on polycrystalline Al (1 ML-C(70)/Al) (ML-monolayer), pure and doped with sodium atoms. The data obtained from the pure ML chemisorbed on Al surface show a semiconducting behavior of the system, which is characterized by a covalent bond between the adsorbate and the substrate. The same data show also that the C(70) molecules tend to orient themselves with the C(5v) axis perpendicular to the surface in analogy to what observed for 1 ML-C(70)/Cu(111). By doping the sample with sodium atoms a charge transfer from the alkali atoms to the lowest unoccupied molecular orbital (LUMO) of the C(70) molecules takes place, as underlined by the gradual increasing intensity of the C(70) LUMO peak as a function of doping. Nevertheless, no metallic phases are observed for any doping step.

Selectivity of auger decays to the local surface environment

The line shape of the Auger decay of adatoms is studied by a joint theoretical and experimental effort, the former within a DFT framework, and the latter with synchrotron radiation measurements. We investigate the KL(2,3)V Auger deexcitation of Na on Al(111), a system with different adsorption geometries. In particular, we study the (sqrt[3]xsqrt[3])R30 degrees phase at 1/3 ML (monolayer) and the more complex (2 x 2) structure at 1/2 ML coverage. From the comparison between theory and experiment, we unambiguously determine features that allow for the determination of the adsorption environment from the adatom Auger spectrum.

Temperature driven reversible breakdown of pseudomorphism in ultrathin Fe/Cu3Au films

We observe that ultrathin Fe/Cu(3)Au(001) films in the 6-13 A thickness range, beyond the thickness of pseudomorphism breakdown at room temperature, exhibit a temperature dependent structural phase transition in the range T(c) approximately 345-380 K. In the high temperature state the Fe film becomes pseudomorphic, while breakdown of pseudomorphism reversibly occurs as the system is cooled below the transition temperature. The difference between substrate and overlayer thermal expansion coefficient is highlighted as the driving force for the observed transition.

Atomically resolved images from near node photoelectron holography experiments on Al(111)

Szöke's concept for electron holography is hampered by forward scattering that dominates electron diffraction from electron point sources below the surface top layer. Forward scattering was proposed to be suppressed if the anisotropic nature of the electron source wave is exploited [T. Greber and J. Osterwalder, Chem. Phys. Lett. 256, 653 (1996)]. Experiments show a strong suppression of forward scattering in Al(111) if Al 2s photoelectrons (E(kin) = 952 eV) are measured near the nodal plane of the outgoing p wave. The holographic reconstruction from such diffraction data provides three dimensional images of atomic sites in unit cells with a size of more than 10 A.

Atomic-scale structure and catalytic reactivity of the RuO(2)(110) surface

The structure of RuO(2)(110) and the mechanism for catalytic carbon monoxide oxidation on this surface were studied by low-energy electron diffraction, scanning tunneling microscopy, and density-functional calculations. The RuO(2)(110) surface exposes bridging oxygen atoms and ruthenium atoms not capped by oxygen. The latter act as coordinatively unsaturated sites-a hypothesis introduced long ago to account for the catalytic activity of oxide surfaces-onto which carbon monoxide can chemisorb and from where it can react with neighboring lattice-oxygen to carbon dioxide. Under steady-state conditions, the consumed lattice-oxygen is continuously restored by oxygen uptake from the gas phase. The results provide atomic-scale verification of a general mechanism originally proposed by Mars and van Krevelen in 1954 and are likely to be of general relevance for the mechanism of catalytic reactions at oxide surfaces.

Polycyclic aromatic hydrocarbons in bovine lens

A study was performed to detect the presence of polycyclic aromatic hydrocarbons (PAHs) in bovine eyes. Twenty fresh bovine eyes were used to detect the presence of PAHs in lens, vitreous and aqueous by HPLC and spectrofluorometer. In lenticular tissue the mean amount of PAHs was 0.0271 microgram/g and the mean level of PAH in each lens was 0.059 microgram. Five types of PAHs (pyrene, fluoranthene, triphenylene, 1.2-benzanthracene and chrysene) were found in the lenses but none in vitreous and aqueous. These data indicate that PAHs are present only in the lens of the bovine eye. The source of these substances in mammalian clear lens is unclear.

Polycyclic aromatic hydrocarbons in clear and cataractous human lenses

In this histochemical study on the ocular lens, the authors test for the presence of various sorts of the (unsaturated) polycyclic aromatic hydrocarbon (PAH) in 66, both clear and cataractous human lenses. A statistically significant greater amount of PAH is found in the cataractous lenses studied (p < 0.01), with two kind of PAH, phenanthrene and 1,2-benzoanthracene, appearing exclusively in lenses with cataracts. The authors put forward a hypothesis on the cataractogenic effect of PAH on the basis of its interference with lens metabolism and the subsequent production and release of free-radicals.

[Hepatocellular carcinoma (HCC): the long-term response to tamoxifen. A clinical case report and review of the literature]

A 52 years old female with hepatocellular carcinoma (HCC) was treated successfully with Tamoxifen. The tumor involved IV hepatic segment with hilar extension and biliary obstruction, was unresectable, and had been pretreated with hormone-chemotherapy. Tamoxifen treatment induced a PR of 6 months, with normalization of serum bilirubin, reduction of alfa-fetoprotein level and improvement of PS, and was free of toxicity. At disease progression intra-arterial chemotherapy with Cis platinum (CDDP) and 5-FU gave a further 4 months PR, until disease progression and exitus in hepatic coma. Tamoxifen therapy, even in the absence of E.R. assay is a useful tool in the management of HCC patients. Further randomized studies are necessary to ascertain the role of Tamoxifen in the treatment of HCC.