ABSTRACT
We examine the coherent spin-dependent transport properties of the van der Waals (vdW) ferromagnet Fe4GeTe2 using density functional theory combined with the nonequilibrium Green's function method. Our findings reveal that the conductance perpendicular to the layers is half-metallic, meaning that it is almost entirely spin-polarized. This property persists from the bulk to a single layer, even under significant bias voltages and with spin-orbit coupling. Additionally, using dynamical mean field theory for quantum transport, we demonstrate that electron correlations are important for magnetic properties but minimally impact the conductance, preserving almost perfect spin-polarization. Motivated by these results, we then study the tunnel magnetoresistance (TMR) in a magnetic tunnel junction consisting of two Fe4GeTe2 layers with the vdW gap acting as an insulating barrier. We predict a TMR ratio of â¼500%, which can be further enhanced by increasing the number of Fe4GeTe2 layers in the junction.
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
The aim of this study was to assess the impact of BMI on perioperative outcomes in patients undergoing VATS lobectomy or segmentectomy. Data from 5088 patients undergoing VATS lobectomy or segmentectomy, included in the VATS Group Italian Registry, were collected. BMI (kg/m2) was categorized according to the WHO classes: underweight, normal, overweight, obese. The effects of BMI on outcomes (complications, 30-days mortality, DFS and OS) were evaluated with a linear regression model, and with a logistic regression model for binary endpoints. In overweight and obese patients, operative time increased with BMI value. Operating room time increased by 5.54 minutes (S.E. = 1.57) in overweight patients, and 33.12 minutes (S.E. = 10.26) in obese patients (P < 0.001). Compared to the other BMI classes, overweight patients were at the lowest risk of pulmonary, acute cardiac, surgical, major, and overall postoperative complications. In the overweight range, a BMI increase from 25 to 29.9 did not significantly affect the length of stay, nor the risk of any complications, except for renal complications (OR: 1.55; 95% CI: 1.07-2.24; P = 0.03), and it reduced the risk of prolonged air leak (OR: 0.8; 95% CI: 0.71-0.90; P < 0.001). 30-days mortality is higher in the underweight group compared to the others. We did not find any significant difference in DFS and OS. According to our results, obesity increases operating room time for VATS major lung resection. Overweight patients are at the lowest risk of pulmonary, acute cardiac, surgical, major, and overall postoperative complications following VATS resections. The risk of most postoperative complications progressively increases as the BMI deviates from the point at the lowest risk, towards both extremes of BMI values. Thirty days mortality is higher in the underweight group, with no differences in DFS and OS.
Subject(s)
Overweight , Thinness , Humans , Overweight/complications , Body Mass Index , Thinness/complications , Pneumonectomy/adverse effects , Thoracic Surgery, Video-Assisted/adverse effects , Treatment Outcome , Obesity/complications , Postoperative Complications/etiology , Retrospective StudiesABSTRACT
Spin-resolved momentum microscopy and theoretical calculations are combined beyond the one-electron approximation to unveil the spin-dependent electronic structure of the interface formed between iron (Fe) and an ordered oxygen (O) atomic layer, and an adsorbate-induced enhancement of electronic correlations is found. It is demonstrated that this enhancement is responsible for a drastic narrowing of the Fe d-bands close to the Fermi energy (EF ) and a reduction of the exchange splitting, which is not accounted for in the Stoner picture of ferromagnetism. In addition, correlation leads to a significant spin-dependent broadening of the electronic bands at higher binding energies and their merging with satellite features, which are manifestations of a pure many-electron behavior. Overall, adatom adsorption can be used to vary the material parameters of transition metal surfaces to access different intermediate electronic correlated regimes, which will otherwise not be accessible. The results show that the concepts developed to understand the physics and chemistry of adsorbate-metal interfaces, relevant for a variety of research areas, from spintronics to catalysis, need to be reconsidered with many-particle effects being of utmost importance. These may affect chemisorption energy, spin transport, magnetic order, and even play a key role in the emergence of ferromagnetism at interfaces between non-magnetic systems.
ABSTRACT
Background: Persistent air leak and the management of intraoperative blood loss are common threats in thoracic surgical practice. The availability of new procedures, technology and materials is constantly evolving topical hemostats and surgical sealants must be added to this toolkit. Topical hemostats and surgical sealants differ according to their chemical nature and physical characteristics, to their origin and mechanism of action, regulatory/registration and vigilance paths. A Delphi consensus was set to highlight the different points of view on the use of topical haemostatic products and sealants among the members of Italian Society of thoracic surgery. Methods: The board was formed by a group of five Italian experts; in the first phase after a careful review of the scientific literature and two rounds, the board finally generated 16 consensus statements for testing across a wider audience. During the second phase, the statements were collated into a questionnaire, which was electronically sent to a panel of 46 Italian surgeons, experts in the field. Results: Out of 46 Italian surgeons, 33 (72%) panel members responded to the Delphi questionnaire. All the items reached a positive consensus, with elevated levels of agreement, as demonstrated by the presence of a 100% consensus for nine items. For the remaining 7 statements the minimum level of consent was 88% (29 participants approved the statement and 4 disagreed) and the maximum was 97% (32 participants approved the statement and 1 was in disagreement). Conclusions: The present Delphi analysis shows that air leak and intraoperative bleeding are clinical problems well known among thoracic surgeons. Nevertheless, the aim of the scientific societies and of the group of experts is to execute the education activities in the surgery community. This Delphi survey suggest the need of wider and updated scientific information about technical and registration characteristics of most recent technologic solutions, such as the of topical hemostats and surgical sealants to provide healthcare and administrative staff with the opportunity to work and interact through a common and shared language and eventually to guarantee minimal requirements of assistance.
ABSTRACT
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.
ABSTRACT
BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
ABSTRACT
OBJECTIVES: This study reports the results of an international expert consensus process evaluating the assessment of intraoperative air leaks (IAL) and treatment of postoperative prolonged air leaks (PAL) utilizing a Delphi process, with the aim of helping standardization and improving practice. METHODS: A panel of 45 questions was developed and submitted to an international working group of experts in minimally invasive lung cancer surgery. Modified Delphi methodology was used to review responses, including 3 rounds of voting. The consensus was defined a priori as >50% agreement among the experts. Clinical practice standards were graded as recommended or highly recommended if 50-74% or >75% of the experts reached an agreement, respectively. RESULTS: A total of 32 experts from 18 countries completed the questionnaires in all 3 rounds. Respondents agreed that PAL are defined as >5 days and that current risk models are rarely used. The consensus was reached in 33/45 issues (73.3%). IAL were classified as mild (<100 ml/min; 81%), moderate (100-400 ml/min; 71%) and severe (>400 ml/min; 74%). If mild IAL are detected, 68% do not treat; if moderate, consensus was not; if severe, 90% favoured treatment. CONCLUSIONS: This expert consensus working group reached an agreement on the majority of issues regarding the detection and management of IAL and PAL. In the absence of prospective, randomized evidence supporting most of these clinical decisions, this document may serve as a guideline to reduce practice variation.
Subject(s)
Pneumonectomy , Consensus , Delphi Technique , Humans , Pneumonectomy/adverse effects , Prospective Studies , Surveys and QuestionnairesABSTRACT
A patient with severe pectus excavatum, dilated ischemic heart disease, and indication for defibrillator implantation for primary prevention of sudden death underwent successful ultrasound-guided serratus anterior plane block and parasternal block with intermuscular two-incision technique implantation with no complications. At follow-up, all the parameters resulted stable with excellent signal sensing.
ABSTRACT
INTRODUCTION: Anesthetic care in patients undergoing thoracic surgery presents specific challenges that necessitate standardized, multidisciplionary, and continuously updated guidelines for perioperative care. METHODS: A multidisciplinary expert group, the Perioperative Anesthesia in Thoracic Surgery (PACTS) group, comprising 24 members from 19 Italian centers, was established to develop recommendations for anesthesia practice in patients undergoing thoracic surgery (specifically lung resection for cancer). The project focused on preoperative patient assessment and preparation, intraoperative management (surgical and anesthesiologic care), and postoperative care and discharge. A series of clinical questions was developed, and PubMed and Embase literature searches were performed to inform discussions around these areas, leading to the development of 69 recommendations. The quality of evidence and strength of recommendations were graded using the United States Preventative Services Task Force criteria. RESULTS: Recommendations for preoperative care focus on risk assessment, patient preparation (prehabilitation), and the choice of procedure (open thoracotomy vs. video-assisted thoracic surgery). CONCLUSIONS: These recommendations should help pulmonologists to improve preoperative management in thoracic surgery patients. Further refinement of the recommendations can be anticipated as the literature continues to evolve.
ABSTRACT
INTRODUCTION: Anesthetic care in patients undergoing thoracic surgery presents specific challenges that require a multidisciplinary approach to management. There remains a need for standardized, evidence-based, continuously updated guidelines for perioperative care in these patients. METHODS: A multidisciplinary expert group, the Perioperative Anesthesia in Thoracic Surgery (PACTS) group, was established to develop recommendations for anesthesia practice in patients undergoing elective lung resection for lung cancer. The project addressed three key areas: preoperative patient assessment and preparation, intraoperative management (surgical and anesthesiologic care), and postoperative care and discharge. A series of clinical questions was developed, and literature searches were performed to inform discussions around these areas, leading to the development of 69 recommendations. The quality of evidence and strength of recommendations were graded using the United States Preventive Services Task Force criteria. RESULTS: Recommendations for intraoperative care focus on airway management, and monitoring of vital signs, hemodynamics, blood gases, neuromuscular blockade, and depth of anesthesia. Recommendations for postoperative care focus on the provision of multimodal analgesia, intensive care unit (ICU) care, and specific measures such as chest drainage, mobilization, noninvasive ventilation, and atrial fibrillation prophylaxis. CONCLUSIONS: These recommendations should help clinicians to improve intraoperative and postoperative management, and thereby achieve better postoperative outcomes in thoracic surgery patients. Further refinement of the recommendations can be anticipated as the literature continues to evolve.
ABSTRACT
BACKGROUND: A two-incision technique, in association with inter-muscular positioning of the subcutaneous defibrillator (S-ICD), is now the most frequently adopted implantation approach in Europe. Ultrasound-guided serratus anterior plane block (SAPB) has been proposed to provide anesthesia/analgesia during S-ICD implantation. OBJECTIVE: We performed a case-control analysis in which a standardized SAPB approach was compared with the typical local anesthesia and sedation approach. METHODS: Ninety-one consecutive patients underwent implantation of an S-ICD with the SAPB approach for anesthesia/analgesia at 10 centers. The control group consisted of 55 consecutive patients who underwent S-ICD implantation with a standard local approach. RESULTS: The mean procedure duration was 59 ± 15 minutes in the SAPB group and 76 ± 23 minutes in the control group (P < .001). No operative complications were reported in either group. During the procedure, 79 (87%) patients in the SAPB group and 25 (46%) patients in the control group (P < .001) remained awake. Lower values of pain intensity at the device pocket (P = .005) and the lateral tunneling site (P = .046) were reported in the SAPB group. The difference in static (P = .002) and dynamic (P = .007) pain intensity between the groups persisted at 1 hour, while no differences were observed 6 hours after the end of the procedure. CONCLUSIONS: SAPB is feasible and effective in providing anesthesia/analgesia during S-ICD implantation. The procedures were successfully accomplished and no complications occurred in either group. However, SAPB was associated with lower pain levels, enabling the need for sedation to be reduced and more patients to remain awake. Moreover, it resulted in shorter procedure durations.
Subject(s)
Defibrillators, Implantable , Electric Countershock/instrumentation , Muscle, Skeletal/innervation , Nerve Block , Pain, Postoperative/prevention & control , Prosthesis Implantation/instrumentation , Adult , Aged , Case-Control Studies , Electric Countershock/adverse effects , Female , Humans , Italy , Male , Middle Aged , Nerve Block/adverse effects , Operative Time , Pain Measurement , Pain, Postoperative/diagnosis , Pain, Postoperative/etiology , Prospective Studies , Prosthesis Implantation/adverse effects , Registries , Risk Factors , Time Factors , Treatment OutcomeABSTRACT
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.
ABSTRACT
BACKGROUND: Epicardial placement of the left ventricular (LV) lead via a video-assisted thoracoscopic (VAT) approach is an alternative to the standard transvenous technique. HYPOTHESIS: Long-term safety and efficacy of VAT and transvenous LV lead implantation are comparable. To test it, we reviewed our experience and we compared the outcomes of patients who underwent implantation with the two techniques. METHODS: The VAT procedure is performed under general anesthesia, with oro-tracheal intubation and right-sided ventilation, and requires two 5 mm and one 15 mm thoracoscopic ports. After pericardiotomy at the spot of the epicardial target area, pacing measurements are taken and a spiral screw electrode is anchored at the final pacing site. The electrode is then tunneled to the pectoral pocket and connected to the device. RESULTS: 105 patients were referred to our center for epicardial LV lead implantation. After pre-operative assessment, 5 patients were excluded because of concomitant conditions precluding surgery. The remaining 100 underwent the procedure. LV lead implantation was successful in all patients (median pacing threshold 0.8 ± 0.5 V, no phrenic nerve stimulation) and cardiac resynchronization therapy was established in all but one patient. The median procedure time was 75 min. During a median follow-up of 24 months, there were no differences in terms of death, cardiovascular hospitalizations or device-related complications vs the group of 100 patients who had undergone transvenous implantation. Patients of both groups displayed similar improvements in terms of ventricular reverse remodeling and functional status. CONCLUSIONS: Our VAT approach proved safe and effective, and is a viable alternative in the case of failed transvenous LV implantation.
Subject(s)
Cardiac Resynchronization Therapy Devices , Cardiac Resynchronization Therapy , Heart Failure/therapy , Thoracic Surgery, Video-Assisted , Aged , Cardiac Resynchronization Therapy/adverse effects , Case-Control Studies , Female , Functional Status , Heart Failure/diagnosis , Heart Failure/physiopathology , Humans , Male , Operative Time , Recovery of Function , Risk Factors , Thoracic Surgery, Video-Assisted/adverse effects , Time Factors , Treatment Outcome , Ventricular Function, Left , Ventricular RemodelingABSTRACT
OBJECTIVES: Vascular injuries are among the most severe causes of unplanned conversion during VATS lobectomies. The study aimed to analyse the incidence of vascular injuries and their risk factors during VATS lobectomy. METHODS: The Italian VATS lobectomy Registry was used to collect data from 66 Thoracic Surgery Units. From 2013 to October 2016 (out of more than 3,700 patients enrolled) only information from Units with an enrollment >100 VATS lobectomies were retrospectively analysed. Logistic regression analysis was performed on selected variables of the univariate analysis. RESULTS: Ten institutions contributed a total of 1,679 patients. Vascular injuries leading to conversion occurred in 44 (2.6%) patients. Years of experiences were inversely related to the risk of vascular injuries. Univariate analysis showed age, gender, surgical activity, Charlson Index Score and number of resected lymph nodes like significantly associated variables. Multivariate analysis revealed that number of resected lymph nodes, VATS experience ratio (number of VATS lobectomies/total lobectomies performed in the same year at same centre), and surgical activity of the centre were significantly associated with the risk of conversion. Unplanned thoracotomy was correlated with postoperative morbidity. CONCLUSION: Vascular injuries in VATS lobectomies represented a rare complication which could directly affect the postoperative outcomes. The predictive factors for conversion were multifactorial and depended on characteristics of centres and surgeons' seniority. Minimally invasive VATS lobectomy approaches did not influence the risk of vascular damages.