Short-term Venous Patency after Implantation of Permanent Pacemakers or Implantable Cardioverter Defibrillators

AbstractThere is little information on venous patency after pacing leads are inserted in veins during pacemaker or implantable cardioverter defibrillator (ICD) implantation. Herein we present a report on venous patency during the immediate postoperative period after permanent pacemaker or ICD implantation.Subjects and Methods: Twenty-five patients underwent a permanent pacemaker or ICD implantation by venous puncture method, and venography was performed 1 week later. We assessed the pacemaker-implantation side, approach used, implanted device, number of implanted leads, and clinical symptoms.Results: Narrowing of the vein was found in 14 patients (56%), including 7 patients (28%) with occlusion. Stenosis and occlusion were seen more in patients with left-sided implantation than those with right-sided implantation (71% vs. 25%, P < 0.05). ICD implantation was more frequently associated with venous stenosis or occlusion than pacemaker implantation (65% vs. 37.5%, P < 0.05). The approach used and the number of leads implanted did not correlate with venous stenosis or occlusion. Six of the 7 patients who developed complete occlusion showed clinical symptoms.Conclusion: Thrombus formation after pacemaker implantation can occur in the acute stage within 1 week. The incidence of venous stenosis or thrombus formation was higher with leftsided implantation and ICD

Hierarchical nanophase-separated structures created by precisely-designed polymers with complexity

AbstractThis review paper summarizes recent advances in self-assembly of complex polymers, focusing on three characteristic polymeric systems. The first is star-branched polymers of the ABC type, the second one consists of multiblock terpolymers with different chain lengths, while the third comprises supramacromolecular assembly systems with hydrogen and ionic bonding interactions between different polymer species. A quasicrystalline tiling structure with mesoscopic length scale has been found for the first star polymer system as well as the periodic Archimedean tiling structures, and moreover three-dimensional Zincblende network structure has been discovered. Furthermore the hierarchical structures having two length scales have been also found for the ABC star molecules whose chain length ratios, that is, A/B and/or A/C are larger than approximately five. Hierarchical structures with double periodicity have been observed for the hexablock and undecablock terpolymers and it has been revealed that their morphology changes systematically depending on composition of polymeric species. Poly(4-hydroxystyrene) (H) homopolymer was found to be dissolved into microdomain of poly(2-vinylpyridine) formed by poly(styrene-b-2-vinylpyridine) due to hydrogen bonding interaction, resulting in the origin of morphological transitions depending on the composition of H homopolymer added. Hierarchical structures possessing double periodicity have been found for poly(isoprene-b-2-vinylpyridine)/poly(styrene-b-4-hydroxystyrene) blends depending on both volume fractions of component polymers and blend ratio. Blends of different homopolymers with several complementary nucleotides or acid/base moieties on chain ends have been confirmed to show nanophase-separated structures as a result of successful formation of “supramacromolecules”

Ab Initio QM/MM Molecular Dynamics Study on the Excited-State Hydrogen Transfer of 7-Azaindole in Water Solution

Ab initio molecular dynamics (AIMD) simulations for the excited-state hydrogen transfer (ESHT) reaction of 7-azaindole (7AI−(H2O)n; n = 1, 2) clusters in the gas phase and in water are presented. The effective fragment potential (EFP) is employed to model the surrounding water molecules. The AIMD simulations for 7AI−H2O and 7AI−(H2O)2 clusters show an asynchronous hydrogen transfer at t ∼ 50 fs after the photoexcitation. While the ESHT mechanism for 7AI−H2O in water does not change appreciably compared with that in the gas phase, the AIMD simulations on 7AI−(H2O)2 in water solution exhibit two different mechanisms. Since the tautomer form is lower in energy compared to the normal form in the S1 state, 7AI and (H2O)n fragments separate from each other after the ESHT. With the use of the results of the AIMD trajectories, the minimum energy conical intersection point in the tautomer region has also been located

Wide dynamic range charge sensor operation by high-speed feedback control of radio-frequency reflectometry

Semiconductor quantum dots are useful for controlling and observing quantum states and can also be used as sensors for reading out quantum bits and exploring local electronic states in nanostructures. However, challenges remain for the sensor applications, such as the trade-off between sensitivity and dynamic range and the issue of instability due to external disturbances. In this study, we demonstrate proportional-integral-differential feedback control of the radio-frequency reflectometry in GaN nanodevices using a field-programmable gate array. This technique can maintain the operating point of the charge sensor with high sensitivity. The system also realizes a wide dynamic range and high sensor sensitivity through the monitoring of the feedback signal. This method has potential applications in exploring dynamics and instability of electronic and quantum states in nanostructures.Comment: 13 pages, 5 figure

Theoretical study of Ar-MCO (M = Pd, Pt)

Ab initio calculations are performed for noble-gas complexes, Ar-PdCO and Ar-PtCO, by QCISD(T) with a Douglas-Kroll relativistic scheme. The electronic ground states of Ar-PdCO and Ar-PtCO are predicted to be 1Σ with linear equilibrium structure, and the binding energy of Ar is estimated as 5.3 and 8.2 kcal/mol for Ar-PdCO and Ar-PtCO, respectively. The M-C-O (M = Pd, Pt) bending frequency in MCO increases by ∼ 10% in Ar-MCO. The present calculations suggest that the experimentally reported M-C-O bending frequencies for MCO measured in the solid argon matrix are possibly to be assigned to the overtone band of the M-C-O bending mode of Ar-MCO

Relativistic segmented contraction basis sets with core-valence correlation effects for atoms 57La through 71Lu : Sapporo-DK-nZP sets (n = D, T, Q)

For the 15 lanthanide atoms 57La through 71Lu, we report Sapporo-DK-nZP sets (n = D, T, Q), which are natural extensions of the Sapporo-(DK)-nZP sets for lighter atoms and efficiently incorporate the correlation among electrons in the N through P shells as well as the relativistic effect. The present sets well describe the correlation among the 4s and 4p electrons, which are important in the excitation of 4f electrons. Atomic test calculations of 57La, 58Ce, 59Pr, and 60Nd at configuration interaction with the Davidson correction level of theory confirm high performance of the present basis sets. Molecular test calculations are carried out for 57LaF and 70YbF diatomics at the coupled cluster level of theory. The calculated spectroscopic constants approach smoothly to the experimental values as the quality of the basis set increases

Theoretical prediction of noble-gas compounds : Ng-Pd-Ng and Ng-Pt-Ng

Following our recent study on Ng–Pt–Ng (Ng=Ar,Kr,Xe) [J. Chem. Phys. 123, 204321 (2005)], the binding of noble-gas atoms with Pd atom has been investigated by the ab initio coupled cluster CCSD(T) method with counterpoise corrections, including relativistic effects. It is shown that two Ng atoms bind with Pd atom in linear geometry due to the s-d hybridization in Pd where the second Ng atom attaches with much larger binding energy than the first. The binding energies are evaluated as 4.0, 10.2, and 21.5 kcal/mol for Ar–Pd–Ar, Kr–Pd–Kr, and Xe–Pd–Xe, respectively, relative to the dissociation limit, Pd (1S)+2Ng. In the hybrid Ng complexes, the binding energies for XePd and Ng (=Ar,Kr) are evaluated as 4.0 and 6.9 kcal/mol for XePd–Ar and XePd–Kr, respectively. The fundamental frequencies and low-lying vibrational-rotational energy levels are determined for each compound by the variational method, based on the three-dimensional near-equilibrium potential energy surface. Results of vibrational-rotational analyses for Ng–Pt–Ng (Ng=Ar,Kr,Xe) and Xe–Pt–Ng (Ng=He,Ne,Ar,Kr) compounds are also given

A multireference perturbation study of the NN stretching frequency of trans-azobenzene in nπ* excitation and an implication for the photoisomerization mechanism

A multireference second-order perturbation theory is applied to calculate equilibrium structures and vibrational frequencies of trans-azobenzene in the ground and nπ* excited states, as well as the reaction pathways for rotation and inversion mechanism in the nπ* excited state. It is found that the NN stretching frequency exhibits a slight increase at the minimum energy structure in the nπ* state, which is explained by the mixing of the NN stretching mode with the CN symmetric stretching mode. We also calculate the NN stretching frequency at several selected structures along the rotation and inversion pathways in the nπ* state, and show that the frequency decreases gradually along the rotation pathway while it increases by ca. 300 cm^[-1] along the inversion pathway. The frequencies and energy variations along the respective pathways indicate that the rotation pathway is more consistent with the experimental observation of the NN stretching frequency in nπ* excitation