Spin filtering at organic-metal interfaces is often determined by the details of the interaction between the organic molecules and the inorganic magnets used as electrodes. Here we demonstrate a ...spin-filtering mechanism based on the dynamical spin relaxation of the long-living interface states formed by the magnet and weakly physisorbed molecules. We investigate the case of Alq3 on Co and, by combining two-photon photoemission experiments with electronic structure theory, show that the observed long-time spin-dependent electron dynamics is driven by molecules in the second organic layer. The interface states formed by physisorbed molecules are not spin-split, but acquire a spin-dependent lifetime, that is the result of dynamical spin-relaxation driven by the interaction with the Co substrate. Such spin-filtering mechanism has an important role in the injection of spin-polarized carriers across the interface and their successive hopping diffusion into successive molecular layers of molecular spintronics devices.
Organic paramagnetic and electroactive molecules are attracting interest as core components of molecular electronic and spintronic devices. Currently, further progress is hindered by the modest ...stability and reproducibility of the molecule/electrode contact. We report the synthesis of a persistent organic radical bearing one and two terminal alkyne groups to form Au–C σ bonds. The formation and stability of self-assembled monolayers and the electron transport through single-molecule junctions at room temperature have been studied. The combined analysis of both systems demonstrates that this linker forms a robust covalent bond with gold and a better-defined contact when compared to traditional sulfur-based linkers. Density functional theory and quantum transport calculations support the experimental observation highlighting a reduced variability of conductance values for the C–Au based junction. Our findings advance the quest for robustness and reproducibility of devices based on electroactive molecules.
•Dopant O2 molecules do not affect spin transport in Alq3-based spin-valves.•There is no magnetic interaction between O2 molecules in Alq3 films.•Spin transport in Alq3 films may be due to the direct ...coupling between Alq3- ions.•The exchange coupling between Alq3- ions is predicted of the order of 100 K.
The understanding of the physics underlying the performances of spin-valve devices comprising organic semiconductors is still incomplete. According to some recent models, spin transport takes place in an impurity band inside the fundamental gap of the organic semiconductor. This seems to be confirmed by recent experiments performed with La0.7Sr0.3MnO3/Alq3/AlOx/Co devices. The reported results suggest a possible correlation between the magnetoresistance and the variable oxygen doping in the Alq3 spacer. In this paper we investigate the electronic and magnetic properties of oxygen molecules and ions in Alq3 films by means of first-principles calculations to establish whether they indeed play any important role for spin transport in La0.7Sr0.3MnO3/Alq3/AlOx/Co devices. The conclusion is that they probably do not. In fact, we show that O2 molecules do not form an impurity band and there is no magnetic interaction between them. In contrast, we suggest that spin-transport may be enabled by the direct exchange coupling between Alq3- ions.
The energy difference between the high spin and the low spin state of the model compound Fe(NCH)62+ 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.
Objectives
Obesity in Europe, and worldwide, has been an increasing epidemic during the past decades. Moreover, obesity has important implications regarding technical issues and the risks associated ...with surgical interventions. Nevertheless, there is a lack of evidence assessing the influence of obesity on video-assisted thoracic surgery (VATS) lobectomy results. Our study aimed to assess the impact of morbid obesity on perioperative clinical and oncological outcomes after VATS lobectomy using a prospectively maintained nationwide registry.
Methods
The Italian VATS lobectomy Registry was used to collect all consecutive cases from 55 Institutions. Explored outcome parameters were conversion to thoracotomy rates, complication rates, intra-operative blood loss, surgical time, hospital postoperative length of stay, chest tube duration, number of harvested lymph-node, and surgical margin positivity.
Results
From 2016 to 2019, a total of 4412 patients were collected. 74 patients present morbid obesity (1.7%). Multivariable-adjusted analysis showed that morbid obesity was associated with a higher rate of complications (32.8% vs 20.3%), but it was not associated with a higher rate of conversion, and surgical margin positivity rates. Moreover, morbid obesity patients benefit from an equivalent surgical time, lymph-node retrieval, intraoperative blood loss, hospital postoperative length of stay, and chest tube duration than non-morbid obese patients. The most frequent postoperative complications in morbidly obese patients were pulmonary-related (35%).
Conclusion
Our results showed that VATS lobectomy could be safely and satisfactorily conducted even in morbidly obese patients, without an increase in conversion rate, blood loss, surgical time, hospital postoperative length of stay, and chest tube duration. Moreover, short-term oncological outcomes were preserved.
We present a rational design approach to customize the spin texture of surface states of a topological insulator. This approach relies on the extreme multifunctionality of organic molecules that are ...used to functionalize the surface of the prototypical topological insulator (TI) Bi2Se3. For the rational design we use theoretical calculations to guide the choice and chemical synthesis of appropriate molecules that customize the spin texture of Bi2Se3. The theoretical predictions are then verified in angular-resolved photoemission experiments. We show that, by tuning the strength of molecule–TI interaction, the surface of the TI can be passivated, the Dirac point can energetically be shifted at will, and Rashba-split quantum-well interface states can be created. These tailored interface propertiespassivation, spin-texture tuning, and creation of hybrid interface stateslay a solid foundation for interface-assisted molecular spintronics in spin-textured materials.
The difference between subcutaneous implantable cardioverter defibrillators (S-ICDs) and transvenous ICDs (TV-ICDs) concerns a whole extra thoracic implantation, including a defibrillator coil and ...pulse generator, without endovascular components. The improved safety profile has allowed the S-ICD to be rapidly taken up, especially among younger patients. Reports of its role in different cardiac diseases at high risk of SCD such as hypertrophic and arrhythmic cardiomyopathies, as well as channelopathies, is increasing. S-ICDs show comparable efficacy, reliability, and safety outcomes compared to TV-ICD. However, some technical issues (i.e., the inability to perform anti-bradycardia pacing) strongly limit the employment of S-ICDs. Therefore, it still remains only an alternative to the traditional ICD thus far. This review aims to provide a contemporary overview of the role of S-ICDs compared to TV-ICDs in clinical practice, including technical aspects regarding device manufacture and implantation techniques. Newer outlooks and future perspectives of S-ICDs are also brought up to date.
Objective Alveolar air leaks are common after pulmonary resection, often prolonging hospitalization and increasing surgical morbidity and costs. Air leakages result from lung tissue traumatized by ...the dissection of fissures. This randomized and controlled trial evaluates 2 different surgical techniques for the completion of interlobar fissures during pulmonary lobectomy to establish which is superior in preventing air leakage. Methods There were 20 patients in each of the 2 groups: Electrocautery was used for precision dissection and collagen patches were coated with human fibrinogen and thrombin (TachoSil, Nycomed, Vienna, Austria) for aerostasis in the electrocautery and sealant group (ES), and the approved routine surgical procedure with staplers was used in the stapler group (ST). Results Statistically significant reductions of air leakage were found in the ES group in the overall incidence of air leaks (50% vs 95%, P = .0001), duration of air leaks (1.7 days vs 4.5 days, P = .003), and procedure costs (425 euros vs 630.5 euros, P = .0001). There were no complications related to the use of the patches, and a significantly lower incidence of dead pleural space was observed in the ES group (5% vs 40%, P = .020). Conclusion The use of electrocautery dissection and collagen patches coated with human fibrinogen and thrombin (TachoSil, Nycomed, Vienna, Austria) for aerostasis to complete interlobar fissures seems to be safe and effective in reducing alveolar air leaks and procedure costs. Although this pilot study showed advantages in terms of hospitalization and cost benefits, further multicentric studies are required to clarify that these differences are statistically significant.
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
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.
Background/Objectives: The surgical resection of pulmonary metastases is considered a therapeutic option in selected cases. In light of this, we present the results from a national multicenter ...prospective registry of lung metastasectomy. Methods: This retrospective analysis involves data collected prospectively and consecutively in a national multicentric Italian database, including patients who underwent lung metastasectomy. The primary endpoints were the analysis of morbidity and overall survival (OS), with secondary endpoints focusing on the analysis of potential risk factors affecting both morbidity and OS. Results: A total 470 lung procedures were performed (4 pneumonectomies, 46 lobectomies/bilobectomies, 13 segmentectomies and 407 wedge resections) on 461 patients (258 men and 203 women, mean age of 63.1 years). The majority of patients had metastases from colorectal cancer (45.8%). In most cases (63.6%), patients had only one lung metastasis. A minimally invasive approach was chosen in 143 cases (30.4%). The mean operative time was 118 min, with no reported deaths. Morbidity most frequently consisted of prolonged air leaking and bleeding, but no re-intervention was required. Statistical analysis revealed that morbidity was significantly affected by operative time and pulmonary comorbidities, while OS was significantly affected by disease-free interval (DFI) > 24 months (p = 0.005), epithelial histology (p = 0.001) and colorectal histology (p = 0.004) during univariate analysis. No significant correlation was found between OS and age, gender, surgical approach, surgical extent, surgical device, the number of resected metastases, lesion diameter, the site of lesions and nodal involvement. Multivariate analysis of OS confirmed that only epithelial histology and DFI were risk-factors, with p-values of 0.041 and 0.031, respectively. Conclusions: Lung metastasectomy appears to be a safe procedure, with acceptable morbidity, even with a minimally invasive approach. However, it remains a local treatment of a systemic disease. Therefore, careful attention should be paid to selecting patients who could truly benefit from surgical intervention.
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