The energy difference between the high spin and the low spin state of the model compound Fe(NCH) sub(6) super(2+) is investigated by means of Diffusion Monte Carlo (DMC), where special attention is ...dedicated to analyzing the effect of the fix node approximation on the accuracy of the results. For this purpose, we compare several Slater-Jastrow and multireference Slater-Jastrow trial wave functions. We found that a Slater-Jastrow trial wave function constructed with the generalized Kohn-Sham orbitals from hybrid DFT represents the optimal choice. This is understood by observing that hybrid functionals account for the subtle balance between exchange and correlation effects and the respective orbitals accurately describe the ligand-metal hybridization as well as the charge reorganization accompanying the spin transition. Finally the DMC results are compared with those obtained by Hartree-Fock, DFT, CASSCF, and CASPT2. While there is no clear reference value for the high spin-low spin energy difference, DMC and high level CCSD(T) calculations agree within around 0.3 eV.
The risk of complications has been shown to be lower with subcutaneous implantable defibrillator (S-ICD) than with conventional ICDs. Given the low frequency of complications, experience of how to ...manage them is limited. In this paper, we describe generator- and lead-related complications recorded in a series of S-ICD patients, and we propose our conservative approach to managing them.
The study cohort consisted of S-ICD patients who were referred to our institution owing to generator- or lead-related complications requiring surgical intervention. With our "shift and cover" approach, the system component involved is moved from its original position to an alternative, more protected location. In the case of the generator, this involves moving it to an intermuscular pocket. In the case of infections at the parasternal scar, the electrode sleeve is moved away from its original location, stitched, and then covered with the muscular fascia.
Fourteen S-ICD patients were referred to our institution owing to system-related complications. Complications involved the generator in 7 cases (deep pocket infections with erosion, extrusion, or pain), the lead in 5 cases (parasternal infections at the xyphoid incision site), and both the generator and the lead in 2 cases. Complications were managed without completely removing the device and resolved in a single surgical session with no intraoperative complications. During defibrillation testing, the first shock at 65 J was effective in all patients. The shock impedance after revision was significantly lower than that measured during first implantation (59 ± 10 Ohm versus 86 ± 24 Ohm, P = 0.013). In all cases, the cosmetic result was satisfactory. No complications or recurrent infections were reported at the 12-month follow-up visit.
The proposed conservative approach was successful in managing S-ICD complications. The revision procedure allowed to optimize the system configuration in terms of the defibrillation vector, resulting in lower shock impedance values and better device positioning.
We present a bias-controlled spin-filtering mechanism in spin-valves including a hybrid organic chain/graphene interface. Wet growth conditions of oligomeric molecular chains would usually lead, ...during standard CMOS-compatible fabrication processes, to the quenching of spintronics properties of metallic spin sources due to oxidation. We demonstrate by X-ray photoelectron spectroscopy that the use of a protective graphene layer fully preserves the metallic character of the ferromagnetic surface and thus its capability to deliver spin polarized currents. We focus here on a small aromatic chain of controllable lengths, formed by nitrobenzene monomers and derived from the commercial 4-nitrobenzene diazonium tetrafluoroborate, covalently attached to the graphene passivated spin sources thanks to electroreduction. A unique bias dependent switch of the spin signal is then observed in complete spin valve devices, from minority to majority spin carriers filtering. First-principles calculations are used to highlight the key role played by the spin-dependent hybridization of electronic states present at the different interfaces. Our work is a first step towards the exploration of spin transport using different functional molecular chains. It opens the perspective of atomic tailoring of magnetic junction devices towards spin and quantum transport control, thanks to the flexibility of ambient electrochemical surface functionalization processes.
Objective
The objective of the study is to analyse the causes and impact of conversion from VATS to thoracotomy identifying any possible pre-operative risk factors and related consequences.
Methods
...Data from patient who underwent VATS lobectomy (VATS-L) for NSCLC at VATS Group participating centres were retrospectively analysed and divided in two groups: patients treated with VATS-L and patients who suffered from conversion. Predictors of conversion were assessed with univariate and multivariable exact logistic regression. Complications were evaluated as dependent variables of conversion in a Cox multivariable logistic regression model.
Results
A total of 4629 patients underwent planned VATS-L for NSCLC and of these, 432 (9.3%) required conversion; the most frequent causes were bleeding (30.4%) and fibro-calcified hilar lymph nodes (23.9%). The independent risk factors at multivariable analysis model were sex male (OR 1.458,
p
< 0.01), age older than 70 years (OR 1.248,
p
= 0.036) and the clinically node-positive disease (OR 2.258,
p
< 0.01). The mortality rate was similar, but the percentage of patients who suffered from any complication (41.7% vs 24.4%,
p
< 0.01), the complication rate (65% vs 32.2%,
p
< 0.01), chest tube duration (
p
< 0.01) and the hospitalisation rate (
p
< 0.01) were higher for patients converted. Atrial fibrillation (OR 1.471,
p
= 0.019), prolonged air leak (OR 1.403,
p
= 0.043), blood transfusions (OR 4.820,
p
< 0.01), sputum retention (OR 1.80,
p
= 0.027) and acute kidney failure (OR 2.758,
p
= 0.03) were significantly associated with conversion at multivariable analysis.
Conclusions
Conversion is associated with increased surgical morbidity, blood loss and hospital stay. Sex male, old age and the clinical involvement of lymph nodes were the strongest predictors of conversion.
Abstract In this work, we study the interface obtained by depositing a monolayer of a Blatter radical derivative on polycrystalline cobalt. By examining the occupied and unoccupied states at the ...interface, using soft X‐ray techniques, combined with electronic structure calculations, we could simultaneously determine the electronic structure of both the molecular and ferromagnetic sides of the interface, thus obtaining a full understanding of the interfacial magnetic properties. We found that the molecule is strongly hybridized with the surface. Changes in the core level spectra reflect the modification of the molecule and the cobalt electronic structures inducing a decrease in the magnetic moment of the cobalt atoms bonded to the molecules which, in turn, lose their radical character. Our method allowed us to screen, beforehand, organic/ferromagnetic interfaces given their potential applications in spintronics.
The Seebeck effect is very attractive for technological applications as it leads to the direct conversion of heat into electricity. One of the key quantities determining the efficiency of such ...conversion is the thermopower
S
. In this paper we explore theoretically what electronic properties are responsible for the Seebeck effect in molecular junctions with graphite or graphene electrodes. We propose that
S
can be enhanced because of the combined effect of the dip in the density of states at the Fermi energy of these materials and the molecular resonance. Then to understand the impact of the covalent
vs.
non-covalent molecule-carbon bonding we calculate from first principles the electronic and transport properties of graphite/molecule/Au junctions, where both types of bonding have been reported experimentally. We ultimately predict that
S
is about 120 μV K
−1
at room temperature for a 3,5-dimethyl-4-aminobenzene (DMAB) molecule covalently attached to the graphite electrode. This value is one order of magnitude larger than the typical values measured to date for molecular junctions and it is a signature of the direct C-C molecule-graphite bond. Finally we also demonstrate how one can control not just the absolute magnitude of
S
, but also its sign by designing the graphite-molecule contact. Our results lead the way towards the use of junctions with molecules covalently attached to a C-based substrate as possible new improved platforms for molecular thermoelectric devices.
The conversion of heat into electricity is determined by the thermopower. We show that the thermopower of junctions with molecules bonded to graphite can be very large and we then suggest new platforms for molecular-scale thermoelectric devices.
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