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Abstract: Core-excitation spectra observed for small acetic-acid (AcA) clusters have been interpreted with density functional theory calculations. By comparison of O1s(CO/OH)→π∗(CO) bands between formic-acid (FA) and AcA clusters, larger band-shifts were identified in AcA clusters. Substituent R-effects on these bands are examined in terms of geometrical parameters and acid–base properties of constituent carboxylic-acids (R–COOH). Since small carboxylic-acid clusters comprise a centrosymmetric dimer-unit with resonance-assisted hydrogen-bonds (RAHBs), cooperative π-electron delocalization characterized by π-conjugated C3;O bond equalization plays an important role in intermolecular interactions. The larger band-shifts for AcA clusters result from increased π-electron delocalization in the constituent molecules relative to FA clusters. [Copyright &y& Elsevier]

Abstract: In order to examine inner-shell electron excitation and induced chemical processes of hydrogen-bonded (HB) molecular clusters, time-of-flight (TOF) fragment-mass and excitation spectra of deuterium-labeled acetic-acid-d (AAD) have been studied under the effusive and cluster beam conditions. With O1s(CO)→π*CO excitation at 532eV, the TOF spectra of AAD clusters were compared with those of the free molecule. Transient intensity-enhancement of CH3 +/CH3CO+ fragments and growth of mixed-cluster cations, M n D+/M n CH3CO+ could be ascertained in the cluster beams, where AAD molecule is denoted by M. Cluster-specific excitation spectra have been generated by monitoring partial-ion-yields of the mixed-cluster cations. Resonance transitions of O1s(CO/OH)→π*CO were found to shift in energy by +0.37/−0.92eV upon cluster formation. The production of M n D+ can be attributed to a low-energy pathway of deuteron (proton) transfer following fast electronic decays within the clusters made up of a stable dimer-unit with doubly-bridged HBs. The CH3 +/CH3CO+ intensity variation in beam stagnation pressure clearly shows that a local-fragmentation mechanism as previously proposed is also applicable to the fragmentation processes of the small AAD clusters. [Copyright &y& Elsevier]

Abstract: Inner-shell excitation spectra and fragmentation of acetaldehyde (AA) clusters have been studied in the oxygen K-edge region under cluster beam conditions. We identified intense production of a series of protonated clusters (AA) n H+, in the time-of-flight spectra of the AA clusters. Cluster-specific excitation spectra could be generated without contribution of free molecules by monitoring partial-ion-yield spectra of the fragments originating from the clusters. Comparison of the cluster-specific band with the molecular band revealed that the first resonance O1s→π*CO band of small AA clusters shifts to a high energy by ∼0.15eV relative to the free molecule. The O1s→π*CO band of small clusters was compared well with the theoretical prediction derived for the most stable dimer configuration. The band-shift of the O1s→π*CO was interpreted as being due to the augmentation of HOMO–LUMO energy gap upon complexation where a hydrogen bonding interaction could be identified. [Copyright &y& Elsevier]

Abstract: Dissociation of nitrous oxide clusters (N2O) n , induced by core level excitation near the nitrogen K-edge was studied by time-of-flight (TOF) fragment mass spectroscopy. Besides the cluster ions (N2O) n + with n ≦26, we identified another series of NO(N2O) m + with m =0–12 as well as O2 + and N3 + products characteristic of ion-molecule reactions within the clusters. Photoelectron–photoion–photoion-coincidence (PEPIPICO) technique was applied to study dissociation mechanisms and dynamics of core-excited (N2O) n clusters. Charge separation mechanisms of the doubly charged (N2O) n 2+ clusters by Nt(1s→π*) excitation were interpreted in terms of kinetic energy release (KER) and charge separation distance (CSD). [Copyright &y& Elsevier]

Fragmentation of doubly charged ethanol clusters [(C2H5OH)n] following the O 1s ionization has been investigated by means of the photoelectron-photoion-photoion coincidence (PEPIPICO) method. The dominant fission channel of (C2H5OH)n2+ was the formation of protonated cluster ion pairs [H(C2H5OH)l+/H(C2H5OH)m+]. The fragmentation mechanisms of these ion pairs were discussed based on the analysis of the PEPIPICO contour shape. It was clarified that the prominent fragmentation channel was a secondary decay mechanism, where neutral evaporation occurs after charge separation. On the other hand, the formation of small fragment ions was suppressed, excluding the formation of certain specific fragments (H3O+, C2H5+/COH+, and C2H4OH+). The formation of small fragment ions was suppressed due to the cooling effect caused by the neutral evaporation and the decrease in the electrostatic repulsive force caused by charge separation. [ABSTRACT FROM AUTHOR]

Abstract: Ionic fragmentation following the inner-shell photoexcitation of [(CH3)2CO]Ar n heteroclusters was investigated in the Ar L23- and O K-edge regions. A partial ion yield (PIY) measurement revealed that and various acetone fragments (, , , , and ) were produced following the Ar L23-shell excitation. In the O K-edge region, the PIY of O+ exhibited a sharp resonance peak at the O 1s→π∗(Cnce excitation. The selective O+ formation was interpreted as the suppression of statistical fragmentation, which was dominant in isolated acetone, owing to the dissipation of excess energy into Ar clusters. [Copyright &y& Elsevier]

Abstract: Time-of-flight mass spectra have been measured for inner-shell ionization of ethanol molecules, its clusters, and methanol clusters at the oxygen K-edge regions. Only in the case of the ethanol clusters, a fairly intense signal corresponding to H3O+ has been observed. The measurements for ethanol-d 1 (C2H5OD) suggest that at least one H atom in the H3O+ ion originates from the C2H5 group of neighbouring ethanol. It is proposed that in addition to the O–H⋯OH type hydrogen bonding in the ethanol clusters, the H in the C2H5 group and OH interact with each other. [Copyright &y& Elsevier]

Background: We compare the effects of angiotensin-converting enzyme (ACE) inhibitor or angiotensin II type 1 (AT[sub 1] ) receptor blocker on density of myocardial beta-adrenergic receptors (beta-ARs) in a heterotopic heart transplantation model. Methods: Hearts of F344 rats were heterotopically transplanted into Lewis rat recipients immunosuppressed with cyclosporine (10 mg/kg/day). Recipients were treated orally with the AT[sub 1] receptor blocker L-158809 (3 mg/kg/day, n = 6), enalapril (3 mg/kg/day, n = 6), or vehicle only (n = 6) for 90 days. Density of myocordial beta-ARs was determined with an autoradiographic technique using [[sup 3] H]CGP-12177. Results: Graft status, the sum of the functional score and the score for color, was preserved better in the L-158809-treated group (5.8 ± 0.9) and in the enalapril-treated group (5.6 ± 0.8) than in the vehicle-treated group (3.8 ± 0.9, p < 0.05). The grades of graft coronary artery disease in the L-158809-treated group and in the enalapril-treated group were significantly less than that seen in the vehicle-treated group. The density of myocardial beta-AR (fmol/mg of protein) was 3.5 ± 0.5 in the L-158809-treated group (p < 0.05 vs. vehicle-treated group) and 3.2 ± 0.5 (p < 0.05) in the enalapril-treated group but was 2.2 ± 0.4 in the vehicle-treated group. Conclusion: L-158809 is as effective as enalapril in restoring myocardial beta-AR density in immunosuppressed rat transplant model, and this efficacy, as well as the prevention of graft coronary arteriosclerosis, is probably associated with the preservation of graft status.Copyright © 2001 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Hydrogen bonding in acetone clusters was investigated using near-edge x-ray absorption fine structure (NEXAFS) spectroscopy and density functional theory calculations in the carbon and oxygen K-edge regions. The partial-ion-yield (PIY) curves of the cluster ions were measured as the NEXAFS spectra of acetone clusters. In the carbon K-edge region, the first resonance peak, which was assigned to the CCO 1s→π*(C=O) resonance transition, showed no substantial change in the PIY curves of the acetone clusters, while the CCH3 1s→3pπ(CH3) excitation feature was found to be strongly suppressed. The selective suppression of the CCH3 1s→3pπ(CH3) resonance transition can be explained by the change in the character of the 3pπ(CH3) orbital due to the C=O...H–C type of hydrogen-bonding interaction. On the other hand, the NEXAFS spectra of the acetone molecule and clusters were almost identical in the oxygen K-edge region, except for a small shift in the π*(C=O) resonance of 0.13 eV, because the character of the π*(C=O) orbital remained, regardless of the C=O...H–C hydrogen bonding interaction. [ABSTRACT FROM AUTHOR]

Hydrogen bonding in methanol clusters has been investigated by using inner-shell photoabsorption spectroscopy and density functional theory (DFT) calculations in the carbon and oxygen K-edge regions. The partial-ion-yield (PIY) curves of H(CH3OH)n+ were measured as the soft x-ray absorption spectra of methanol clusters. The first resonance peak in the PIY curves, which is assigned to the σ*(O–H) resonance transition, exhibits a 1.20 eV blueshift relative to the total-ion-yield (TIY) curves of molecular methanol in the oxygen K-edge region, while it exhibits a shift of only 0.25 eV in the carbon K-edge region. Decreased intensities of the transitions to higher Rydberg orbitals were observed in the PIY curves of the clusters. The drastic change in the σ*(O–H) resonance transition is interpreted by the change in the character of the σ*(O–H) molecular orbital at the H-donating OH site due to the hydrogen-bonding interaction. [ABSTRACT FROM AUTHOR]

Dissociation of free methyl-formate (MF), HC(O)OCH3, and its clusters (MF)n, (HC(O)OCH3)n, induced by core-level excitation was studied near the oxygen K edge by time-of-flight fragment-mass spectroscopy. Besides the protonated clusters, (MF)nH+ with n≤15, we identified the production for another series of (MF)mCH3OH2+ with m≤14 as well as methyl-oxonium ion, CH3OH2+, characteristic of hydrogen transfer reactions in the cationic clusters. Here, specifically labeled methyl-formate-d (MFD), DC(O)OCH3 was also used to examine the core-excited dissociation mechanisms. Deuterium-labeled experiments indicated that MFD+ with low internal energies, partially generated after the core excitation, produces CH3OD+ via a site-specific deuterium transfer from the α carbonyl in the molecular cation and that CH3OD2+ can be formed via the successive transfer of another deuterium from the neighbor molecule in the clusters. The deuteron (proton) transfer was also found to take place preferentially from the α carbonyl of the neighbor molecule for the production of deuteronated (MFD)nD+, (protonated (MF)nH+), clusters. The minimal energy requirement paths were examined for dimer (MF)2+ cation to support the present dissociation mechanisms of core-excited (MF)n clusters using ab initio molecular-orbital calculations. [ABSTRACT FROM AUTHOR]

Abstract: Dissociation of free acetonitrile-d3 molecule, CD3CN induced by core level excitation was studied near the nitrogen K-edge by time-of-flight fragment mass spectroscopy. A variety of atomic and molecular fragment cations such as D+, CD n +, C2D n +, and CD n CN+ were detected using the effusive CD3CN beam. Photoelectron–photoion–photoion coincidence technique was applied to analyse the dissociation mechanisms and dynamics of doubly charged CD3CN2+ following the N(1s–π *) excitation. The charge separation mechanisms of core-excited CD3CN were discussed in connection with Auger final state distributions. [Copyright &y& Elsevier]

Abstract: Multi-charged Kr ions have been measured using monochromatized undulator radiation combined with a coincidence technique. The coincidence measurements between multi-charged ions and energy-selected Auger electrons have clarified decay processes, as follows. The Auger final states formed through L3M45M45 decays turn significantly into Kr4+ and those through L3M23M45 decays generate Kr5+ mainly. The Auger decays of L3M23M23 types yield Kr6+ dominantly. These findings are consistent with the consideration on energy levels of Kr ions. [Copyright &y& Elsevier]

Abstract: Inner-shell excitation of ethanol cluster was investigated using a partial-ion-yield method at the oxygen K-edge. The resonance feature corresponding to the excitation to the 3sa′ unoccupied orbital was not observed in the partial yield spectra of cluster ions, while it is clearly seen in the total ion yield spectrum. The absence of this feature is explained by the changes in local electronic structures owing to the hydrogen bonding in the clusters. [Copyright &y& Elsevier]

Total photoabsorption cross-sections of trifluoromethyl sulfur pentafluoride, CF3SF5, were measured in the C, F and S K-shell regions by using a double ionization chamber and synchrotron radiation at the SPring-8 facility. The maximum cross sections were found to be 6.3, 5.0 and 1.1 Mb for the C, F and S K-edges, respectively. The spectral features in the F K-shell region were characterized by the photoabsorption spectra of CF4 and SF6 and those in the S K-shell region resemble the peaks of SF6. The observed peaks for CF3SF5 were tentatively assigned on the basis of a comparison with those for CF4 and SF6 measured simultaneously for references. [Copyright &y& Elsevier]

Among a number of techniques for gene transfer in vivo, the direct injection of plasmid DNA into muscle is simple, inexpensive and safe. Although combining direct DNA injection with in vivo electroporation increases the efficiency of gene transfer into muscle, applications of this method have remained limited because of the relatively low expression level. To overcome this problem, we developed a plasmid vector that expresses a secretory protein as a fusion protein with the noncytolytic immunoglobulin Fc portion and used it for electroporation-mediated viral interleukin 10 (vIL-10) expression in vivo. The fusion cytokine vIL-10/mutFc was successfully expressed and the peak serum concentration of vIL-10 was almost 100-fold (195 ng/ml) higher than with a non-fusion vIL-10 expression plasmid. The expressed fusion cytokine suppressed the phytohemagglutinin-induced IFN-γ production by human peripheral blood mononuclear cells and decreased the mortality in a mouse viral myocarditis model as effectively as vIL-10 expression. These results demonstrate that the transfer of plasmid DNA expressing a noncytolytic Fc-fusion cytokine is useful to deliver enhanced levels of cytokine without altering general biological activities. This simple and efficient system should provide a new approach to gene therapy for human diseases and prove very useful for investigating the function of newly discovered secretory protein genes. [ABSTRACT FROM AUTHOR]

A pressure-resisting cell system has been developed for high-pressure high-resolution nuclear magnetic resonance (NMR) measurements up to a maximum pressure of 600 MPa. This cell system is capable of performing high-pressure experiments with any standard spectrometer, including modern high field NMR machines. A full description of the high-pressure NMR assembly mounted on a 750 MHz spectrometer is presented along with a detailed explanation of the procedure for preparing the pressure-resisting quartz and glass cells. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract: Photoabsorption cross-sections of CF2CH2 were measured in the carbon K-edge region and linear time-of-flight mass spectra were acquired at some photon energies across the two π * peaks. The kinetic energy distributions of CH2 + and CF2 + with two components were deduced from the analysis of the mass spectra. The CH2 + ion with high kinetic energies increases with the extent of vibrational excitation of the CF 1s→ π * state, indicating that molecular vibrations play an important role in the photofragmentation of the inner-shell excited molecule. [Copyright &y& Elsevier]

Twenty-four consecutive patients underwent epidural cooling as an adjunct to elective thoracoabdominal aortic repair under moderate systemic hypothermia. One patient suffered from postoperative paraplegia (4%), and another died from subarachnoidal hemorrhage (4%). Details of the technique, the associated care, and the pitfalls will be discussed. [Copyright &y& Elsevier]

A neonate with Ebstein’s anomaly presented with severe cyanosis because of massive right-to-left shunt through an atrial septal defect and reduced blood flow through an unobstructed right ventricular outflow tract. This atypical patient underwent a right modified Blalock-Taussig shunt, which resolved the respiratory . [ABSTRACT FROM AUTHOR]