X-ray photoelectron spectroscopy of high-throughput mechanically exfoliated van der Waals materials.

X-ray photoelectron spectroscopy (XPS) is a widely used and easy accessible characterisation technique for investigating the chemical composition of materials. However, investigating the composition of van der Waals (vdW) flakes by XPS is challenging due to the typical spot size of XPS setups compared to the dimensions of the flakes, which are usually one thousand times smaller than the spot size. In this work, we demonstrate the feasibility of quantitative elemental analysis of vdW materials by using high-throughput mechanical exfoliations, which favour the coverage of arbitrary substrates with flakes of areas of the order of the cm2 using minimal quantities of materials (about 10 µg). We have analysed the chemical composition of MoS2, graphite, WSe2 and FePS3. The high-resolution measurement of their main core levels through XPS demonstrates the absence of significant contamination during the transfer method. In the case of air-sensitive FePS3, the glove box fabrication and its degradation in air are discussed. Overall, this research opens the possibility of evaluating the purity of commercial or lab-synthesized flakes and paves the way towards a more systematic comparison between the composition of vdW materials produced and used among different laboratories.

Protecting TiS3 Photoanodes for Water Splitting in Alkaline Media by TiO2 Coatings.

Titanium trisulfide (TiS3) nanoribbons, when coated with titanium dioxide (TiO2), can be used for water splitting in the KOH electrolyte. TiO2 shells can be prepared through thermal annealing to regulate the response of TiS3/TiO2 heterostructures by controlling the oxidation time and growth atmosphere. The thickness and structure of the TiO2 layers significantly influence the photoelectrocatalytic properties of the TiS3/TiO2 photoanodes, with amorphous layers showing better performance than crystalline ones. The oxide layers should be thin enough to transfer photogenerated charge through the electrode-electrolyte interface while protecting TiS3 from KOH corrosion. Finally, the performance of TiS3/TiO2 heterostructures has been improved by coating them with various electrocatalysts, NiSx being the most effective. This research presents new opportunities to create efficient semiconductor heterostructures to be used as photoanodes in corrosive alkaline aqueous solutions.

Reoperative aortic root surgery: single-center long-term outcomes and literature review.

Background and Objective: Reoperative aortic root surgery has become more and more common over the years and is considered high-risk, with significantly worse outcomes compared to first-procedure root surgery. At our institution, this kind of surgery is frequently performed. The aim of the present review is to describe currently available literature on reoperative surgery on the aortic root in terms of patients' population, indications for surgery and outcomes and to present our center's experience on the matter. Methods: A literature review was performed in order to identify pertinent studies. They were then compared and described. We also described preoperative characteristics, operative strategies and outcomes of all the patients who underwent redo aortic root surgery from January 1986 to December 2022 at our center. Key Content and Findings: Our literature review identified 12 pertinent studies, with a total of 16,627 considered patients. The most frequent indications for redo surgery were endocarditis (35.5%), aneurysm, dissection and pseudoaneurysm. Mean cardiopulmonary bypass (CPB) and cross-clamp times were 218 and 152 minutes, respectively. In-hospital mortality was 12%. When analyzing our center's data, 344 procedures were identified. Aortic root dilation was the most frequent indication (36.9%). Mean CPB and cross-clamp times were 218.0±78.8 and 158.2±49.7 minutes, respectively. In-hospital mortality was 9.6%. Survival at 5 and 15 years was 76.1% and 51.4% respectively. Freedom from further aortic reintervention was 88.1% after 5 years and 64.9% after 15 years. Conclusions: Reoperative aortic root surgery is a difficult cardiac procedure which is linked to significantly higher mortality than first-time root replacement. If it is performed by experienced surgeons with a careful preoperative planning its result can still be satisfactory. Our results showed acceptable rates of mortality and reinterventions at follow-up. Endocarditis, however, was linked to worse outcomes.

Potassium doping of vertically aligned multi-walled carbon nanotubes.

Alkali metal doping of multi-walled carbon nanotubes is of great interest, both fundamentally to explore the effect of dopants on quasi-one-dimensional electrical systems and for energy applications such as alkali metal storage. We present an investigation with complementary photoemission and Raman spectroscopies, fully carried out in an ultra-high vacuum, to unveil the electronic and vibrational response of a forest of highly aligned multi-walled carbon nanotubes by in situ potassium doping. The charge donation by the alkali adatoms induces a plasmon mode, and the density of states undergoes an energy shift consistent with electron donation and band filling of the multi-walled carbon nanotube band structure. The π-states in the valence band and the Raman peaks unveil an evolution that can be ascribed to charge donation and partially to a tensile strain exerted by the K adatoms on the carbon lattice. All these effects are thermally reversible, fostering these materials as a potential system for electronic charge harvesting.

Pediatric torticollis: clinical report and predictors of urgency of 1409 cases.

BACKGROUND: To date, the etiology and risk factors of torticollis are still poorly defined in the pediatric literature. Especially in the Emergency Department (ED) scenario, it is critical to reliably distinguish benign and transient conditions from (potentially) life-threatening disorders. This study describes the clinical characteristics of a large sample of children with torticollis. The aim of our study was to detect epidemiology, etiology and predictive variables associated with a higher risk of life-threatening conditions in acute torticollis. METHODS: We conducted a pediatric retrospective study of acute torticollis over a 13-year period referred to the ED of a tertiary pediatric Hospital. We reported the characteristics in the overall sample and in two subgroups divided according to urgency of the underlying condition. Furthermore, we developed a multivariate model aimed at identifying the main clinical predictors of the need for urgent care. RESULTS: 1409 patients were analyzed (median age 5.7 years, IQR 5.8). A history of trauma was present in 393 patients (27.9%). The symptom most frequently associated with torticollis were pain (83.5%). At least one pathological finding was found in 5.4 to 7.9% of patients undergoing further imaging. Hospitalization was required in 11.1% of cases (median duration 4 days). The most frequent etiologies of torticollis were postural cause (43.1%), traumatic (29.5%), and infective/inflammatory (19.1%). A longer time from onset of torticollis and the presence of headache or vomiting were strongly correlated with an underlying urgent condition, after adjusting for the other clinically and statistically significant variables in the bivariate analysis. CONCLUSION: Our study shows that an urgent condition most commonly occur in patients presenting with history of trauma or headache, vomiting and torticollis for more than 24 h should undergo further diagnostic evaluation and short-term follow-up, restricting invasive or expensive investigations to patients with clinical suspicion of an underlying harmful condition.

Intermixing of Unoccupied States of Metal Phthalocyanine Chains Assembled on Au(110).

A detailed inverse photoemission study unveils the unoccupied electronic structure induced by the adsorption of CuPc and CoPc phthalocyanines on Au(110) reconstructed channels. The different behavior in the two systems is related to the different intermixing of orbitals with the underlying gold states. Broadening of the density of states at the Fermi level is detected after CoPc adsorption, absent in the case CuPc. A detailed comparison with the element-selective X-ray absorption spectroscopy enlightens and complements the IPES results and confirms a surface-driven intermixing of the CoPc orbitals involved in the interaction, with the out-of-plane Co 3dz2 orbital strongly hybridized with the gold electronic states. Moreover, the contribution of the 3d empty states to the IPES data is reported for FePc, CoPc, and CuPc thin films.

[Management of acute type B aortic dissection: treatment and follow-up]. / Gestione della dissezione aortica acuta di tipo B: trattamento e follow-up.

Aortic dissection is a life-threatening condition caused by a tear in the tunica intima which creates a false lumen into the aortic wall. Acute type B aortic dissection (TBAD) is defined by the presence of the entry tear in the aorta distal to the left subclavian artery, without ascending aorta and arch involvement, and accounts for 25-40% of all aortic dissections. Optimal medical therapy (OMT), focused on blood pressure and heart rate control, remains the gold standard treatment, especially for patients with uncomplicated TBAD, while complicated dissections require surgical therapy. Recent studies have shown that a considerable number of patients treated only with OMT develop late aorta-related complications that increase morbidity and mortality, as well as the need for surgical intervention. During the last decades, emerging evidence indicates that thoracic endovascular aortic repair (TEVAR) is safe and effective in the treatment of TBAD, both complicated and uncomplicated, with improved long-term survival outcomes and aortic remodeling in combination with OMT compared to OMT alone. However, in cases of acute uncomplicated TBAD the optimal timing for TEVAR is not entirely clarified and there is lack of long-term evidence. Therefore, the role of pre-emptive TEVAR for these patients is still uncertain and the management of acute uncomplicated TBAD remains challenging.

Distal stent graft-induced new entry (dSINE) after frozen elephant trunk: a scoping review.

Background: The introduction of hybrid total arch replacement with the frozen elephant trunk (FET) technique has improved the field of aortic surgery by allowing single-stage treatment of complex aortic pathologies. Although FET has been associated with favorable aortic remodeling, it is also associated with the potential development of distal stent graft-induced new entries (dSINEs). The aim of our review is to collect data about the incidence and the supposed conditions for the occurrence of dSINE after total hybrid arch replacement with FET technique. Methods: The literature review was performed using PubMed databases from inception to January 2022. A descriptive approach to detect and display supposed risk factors and predictors for dSINE occurrence has been adopted. Results: Eight studies summarized the state-of-the-art of dSINE in a total number of 544 FET procedures performed to treat acute and chronic aortic dissections. The scoping review showed dSINEs occurrence in 69 patients (12.7%). The mean time between surgery and the diagnosis ranged from 12.6 to 30.6 months. Most patients that developed dSINE received endovascular treatment, whereas a couple of them needed open surgery. According to our experience, from January 2007 to December 2021, in 225 FET procedures a total of 54 cases of dSINE, both with Thoraflex and E-vita grafts have been detected. The mean time between the surgical procedure and the diagnosis was 27.2±33.6 months. Conclusions: dSINEs are frequent complications after FET. Although not emergent, they require proper treatment. Due to dSINE's asymptomatic nature and potential harm, a rigorous follow-up including angio-computed tomography (CT) should be planned.

MoS2 Photoelectrodes for Hydrogen Production: Tuning the S-Vacancy Content in Highly Homogeneous Ultrathin Nanocrystals.

Tuning the electrocatalytic properties of MoS2 layers can be achieved through different paths, such as reducing their thickness, creating edges in the MoS2 flakes, and introducing S-vacancies. We combine these three approaches by growing MoS2 electrodes by using a special salt-assisted chemical vapor deposition (CVD) method. This procedure allows the growth of ultrathin MoS2 nanocrystals (1-3 layers thick and a few nanometers wide), as evidenced by atomic force microscopy and scanning tunneling microscopy. This morphology of the MoS2 layers at the nanoscale induces some specific features in the Raman and photoluminescence spectra compared to exfoliated or microcrystalline MoS2 layers. Moreover, the S-vacancy content in the layers can be tuned during CVD growth by using Ar/H2 mixtures as a carrier gas. Detailed optical microtransmittance and microreflectance spectroscopies, micro-Raman, and X-ray photoelectron spectroscopy measurements with sub-millimeter spatial resolution show that the obtained samples present an excellent homogeneity over areas in the cm2 range. The electrochemical and photoelectrochemical properties of these MoS2 layers were investigated using electrodes with relatively large areas (0.8 cm2). The prepared MoS2 cathodes show outstanding Faradaic efficiencies as well as long-term stability in acidic solutions. In addition, we demonstrate that there is an optimal number of S-vacancies to improve the electrochemical and photoelectrochemical performances of MoS2.

Room-temperature synthesis of 2D-Ti3C2Tx nano-sheets by organic base treatment.

The growing demand for improved electrochemical performance in energy storage systems has stimulated research into advanced two-dimensional (2D) materials for electrodes. In this work, we obtain a layered MXene compound by exfoliating a titanium aluminum carbide precursor using tetramethylammonium hydroxide (TMAOH) ions in a full room temperature process followed by manual shaking. The hexagonal crystal structure and composition of the layered materials are characterized using different techniques. X-Ray diffraction shows the formation of 2D nano-sheets before and after the TMAOH treatment via its characteristic (002) diffraction peak, bringing to light an increase in the interlayer spacing after treatment. Scanning electron microscopy images confirm the layered morphology, whose composition is determined by energy dispersive x-ray analysis for the bulk material and by x-ray photoelectron spectroscopy for the surface of the obtained compounds. This study demonstrates a promising route to enhance delamination of this MXene 2D material in a low-cost room-temperature approach.

Preliminary Air Quality and Microclimatic Conditions Study in the Santuario della Beata Vergine dei Miracoli in Saronno (VA).

In the present work, the microclimatic conditions (temperature (T), relative humidity (RH), and illuminance (I)), together with the air quality (both aerosol particulate matter (PM) and gaseous pollutants), were monitored to evaluate the environmental conditions inside the Santuario della Beata Vergine dei Miracoli in Saronno (VA), a masterpiece of the Italian Renaissance. For this purpose, dataloggers were used to carry out the T, RH, and I measurements, whereas an optical particle counter (OPC) was employed to perform the particle count and determine the concentration of the aerosol PM. Finally, diffusive passive samplers were used to determine the concentration of nitrogen dioxide (NO2) and BTEX (benzene, toluene, ethylbenzene, and xylenes). To identify possible spatial variations, the studies were conducted at different sites and different heights in the Sanctuary. Particular focus was given to the Easter week during which liturgical services attracting large numbers of people were carried out. Additionally, a comparison with the outdoor values was performed to highlight the accumulation phenomena and other variations in the concentrations of the species. Despite the indoor concentrations of pollutants and variations in the thermohygrometric parameters being generally lower compared to the outdoors (e.g., 5.2-15.0 µg m-3 versus 17.7-45.3 µg m-3 for NO2), the microclimatic conditions were often not in line with the Italian legislation and technical standards.

Tuning the Electronic Response of Metallic Graphene by Potassium Doping.

Electron doping of graphene has been extensively studied on graphene-supported surfaces, where the metallicity is influenced by the substrate. Herewith we propose potassium adsorption on free-standing nanoporous graphene, thus eluding any effect due to the substrate. We monitor the electron migration in the π* downward-shifted conduction band. In this rigid band shift, we correlate the spectral density of the π* state in the upper Dirac cone with the associated plasmon, blue-shifted with increasing K dose, as deduced by electron energy loss spectroscopy. These results are confirmed by the Dirac plasmon activated by the C 1s emitted electrons, thanks to spatially resolved photoemission. This crosscheck constitutes a reference on the correlation between the electronic π* states in the conduction band and the Dirac plasmon evolution upon in situ electron doping of fully free-standing graphene.

Effect of Preoperative Right Ventricular Dysfunction on Heart Transplantation Outcomes.

BACKGROUND: We investigated if the occurrence of preoperative right ventricular dysfunction is capable of influencing heart transplant results in terms of in-hospital mortality, incidence of primary graft dysfunction, and follow-up mortality. METHODS: We retrospectively analyzed 517 patients who underwent heart transplant between January 2000 and December 2020. We defined right ventricular dysfunction (RVD), as central venous pressure (CVP) > 15 mm Hg and CVP/pulmonary capillary wedge pressure ratio > 0.63. We identified 2 subgroups in our population: 33 patients with preoperative RVD and 484 patients without RVD. RESULTS: In-hospital mortality was 7.9%. Severe early graft failure occurred in 6.6% of patients, with 26 patients (5.1%) needing intra-aortic balloon pump and 17 patients (3.3%) needing extracorporeal membrane oxygenation support. Clinical variables that significantly influenced in-hospital mortality were age, peripheral artery disease, and bilirubin > 1.5 mg/dL, while hemodynamic variables influencing in-hospital mortality were CVP (odds ratio [OR], 1.09 [confidence interval {CI}, 1.03-1.15], P = .004], pulmonary artery systolic pressure (OR, 1.02 [CI, 1.00-1.04], P = .05), CVP/pulmonary capillary wedge pressure ratio (OR, 2.78 [CI, 1.14-6.80], P = .025), pulmonary vascular resistance (OR, 1.15 [CI, 1.01-1.32], P = .042), transpulmonary gradient (TPG) (OR, 1.11 [CI, 1.03-1.18], P = .003) , diastolic transpulmonary gradient (OR, 1.10 [CI, 1.02-1.20], P = .015], together with right ventricular dysfunction (OR, 3.56 [CI, 1.44-8.80], P = .011). On the other hand, clinical variables influencing the incidence of early graft failure were body mass index (calculated as weight in kilograms divided by height in meters squared) > 30, peripheral artery disease, bilirubin > 1.5 mg/dL, Model for End-Stage Liver Disease score excluding international normalized ratio before transplant, and preoperative extracorporeal membrane oxygenation support, while hemodynamic variables were pulmonary arterial systolic pressure (OR, 1.03 [CI, 1.00-1.05], P = .016), TPG (OR, 1.08 [1.01-1.17], P = .03), and right ventricular dysfunction (OR, 3.00 [CI, 1.07-8.40] P = .046). On the multivariable analysis, RVD and TPG were independent predictors of in-hospital mortality, while only TPG was a predictor of early graft failure. Follow-up mortality was 38.7% and was influenced by recipient age, recipient body mass index, and preoperative diabetes. Moreover, 1-, 5-, and 10-year survival of patients with preoperative RVD was significantly worse than patients without RVD (log-rank = 0.001). CONCLUSIONS: In our population, RVD influenced both in-hospital and long-term results after heart transplant. For these reasons, it appears crucially important to optimize preoperative right ventricular function to improve these patients' outcomes.

Spectromicroscopy Study of Induced Defects in Ion-Bombarded Highly Aligned Carbon Nanotubes.

Highly aligned multi-wall carbon nanotubes were investigated with scanning electron microscopy (SEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) before and after bombardment performed using noble gas ions of different masses (argon, neon and helium), in an ultra-high-vacuum (UHV) environment. Ion irradiation leads to change in morphology, deformation of the carbon (C) honeycomb lattice and different structural defects in multi-wall carbon nanotubes. One of the major effects is the production of bond distortions, as determined by micro-Raman and micro-X-ray photoelectron spectroscopy. We observe an increase in sp3 distorted bonds at higher binding energy with respect to the expected sp2 associated signal of the carbon 1s core level, and increase in dangling bonds. Furthermore, the surface damage as determined by the X-ray photoelectron spectroscopy carbon 1s core level is equivalent upon bombarding with ions of different masses, while the impact and density of defects in the lattice of the MWCNTs as determined by micro-Raman are dependent on the bombarding ion mass; heavier for helium ions, lighter for argon ions. These results on the controlled increase in sp3 distorted bonds, as created on the multi-wall carbon nanotubes, open new functionalization prospects to improve and increase atomic hydrogen uptake on ion-bombarded multi-wall carbon nanotubes.

Homogeneous Spatial Distribution of Deuterium Chemisorbed on Free-Standing Graphene.

Atomic deuterium (D) adsorption on free-standing nanoporous graphene obtained by ultra-high vacuum D2 molecular cracking reveals a homogeneous distribution all over the nanoporous graphene sample, as deduced by ultra-high vacuum Raman spectroscopy combined with core-level photoemission spectroscopy. Raman microscopy unveils the presence of bonding distortion, from the signal associated to the planar sp2 configuration of graphene toward the sp3 tetrahedral structure of graphane. The establishment of D-C sp3 hybrid bonds is also clearly determined by high-resolution X-ray photoelectron spectroscopy and spatially correlated to the Auger spectroscopy signal. This work shows that the low-energy molecular cracking of D2 in an ultra-high vacuum is an efficient strategy for obtaining high-quality semiconducting graphane with homogeneous uptake of deuterium atoms, as confirmed by this combined optical and electronic spectro-microscopy study wholly carried out in ultra-high vacuum conditions.

"Why is frozen elephant trunk better than classical elephant trunk?"

The treatment of complex aortic arch disease, in chronic or acute setting, has always represented a fascinating challenge for the heart surgeon also because, often, the involvement of the aortic arch is associated with a simultaneous involvement of the ascending aorta and of the proximal portion of the descending thoracic aorta. In recent years, there have been many surgical and/or endovascular techniques and approaches in a single step or multiple steps proposed with the aim of treating and simplifying these complex conditions. The first procedure available for this purpose was the conventional elephant trunk technique, proposed by the German surgeon Hans Borst, back in 1983. In the following years, the technique has undergone modifications, up to what is nowadays considered its most modern evolution, represented by the frozen elephant trunk which allows managing the proximal descending thoracic aorta using the antegrade release of a self-expandable stent graft. In this review article, we try to analyze the advantages and drawbacks of both techniques from clinical and practical points of view.

Therapeutic alternatives in chronic thromboembolic pulmonary hypertension: from pulmonary endarterectomy to balloon pulmonary angioplasty to medical therapy. State of the art from a multidisciplinary team.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease with a very complex pathophysiology differing from other causes of pulmonary hypertension (PH). It is an infrequent consequence of acute pulmonary embolism that is frequently misdiagnosed. Pathogenesis has been related to coagulation abnormalities, infection or inflammation, although these disturbances can be absent in many cases. The hallmarks of CTEPH are thrombotic occlusion of pulmonary vessels, variable degree of ventricular dysfunction and secondary microvascular arteriopathy. The definition of CTEPH also includes an increase in mean pulmonary arterial pressure of more than 25 mmHg with a normal pulmonary capillary wedge of less than 15 mmHg. It is classified as World Health Organization group 4 PH, and is the only type that can be surgically cured by pulmonary endarterectomy (PEA). This operation needs to be carried out by a team with strong expertise, from the diagnostic and decisional pathway to the operation itself. However, because the disease has a very heterogeneous phenotype in terms of anatomy, degree of PH and the lack of a standard patient profile, not all cases of CTEPH can be treated by PEA. As a result, PH-directed medical therapy traditionally used for the other types of PH has been proposed and is utilized in CTEPH patients. Since 2015, we have been witnessing the rebirth of balloon pulmonary angioplasty, a technique first performed in 2001 but has since fallen out fashion due to major complications. The refinement of such techniques has allowed its safe utilization as a salvage therapy in inoperable patients. In the present keynote lecture, we will describe these therapeutic approaches and results.

Impact of Predicted Heart Mass-Based Donor-Recipient Size Matching on Transplant Outcomes.

BACKGROUND: Currently, guidelines for appropriate donor sizing in recipients mostly focuses on donor-recipient body weight matching. The purpose is to retrospectively determine the impact of predicted heart mass (pHM)-based size matching on heart transplant (HT) outcomes. METHODS: According to our institutional registry, 512 consecutive adult patients underwent HT between January 2000 and August 2020. For each patient, pHM and donor-recipient pHM ratio were calculated. Patients were partitioned into quintiles in terms of pHM ratio: undersizing 2, undersizing 1, reference, oversizing 1, and oversizing 2, with mean pHM donor-recipient ratio of 0.81, 0.96, 1.04, 1.12, and 1.28, respectively. Severe early graft failure and 30-day, 90-day, 1-year, and 10-year mortality were analyzed as outcomes. RESULTS: Recipients of the most oversized group were mostly female (P < .001), had higher preoperative pulmonary vascular resistance (P = .009), had higher rate of mechanical circulatory support (P < .05), and showed a lower United Network for Organ Sharing score (P = .041); the respective donors were younger and more frequently male (P = .001). Ischemic time was similar in all groups (P = .358). Pulmonary vascular resistance (P = .023; odds ratio [OR], 2.38), preoperative mechanical circulatory support (P = .05; OR, 3.06), and United Network for Organ Sharing score (P = .033; OR, 1.76) were identified as risk factors for early mortality. Donor-recipient pHM ratio did not impact early graft failure (P = .871) and early mortality (P = .526). Survival analysis after adjustment for pHM ratio subgroups did not show any difference in outcomes. CONCLUSIONS: A wide range of pHM ratios seems to be safe. A careful allocation of organs, by considering a pHM ratio mismatch, may balance rescue preoperative clinical profiles and preserve HT outcomes.

Gap Opening in Double-Sided Highly Hydrogenated Free-Standing Graphene.

Conversion of free-standing graphene into pure graphane─where each C atom is sp3 bound to a hydrogen atom─has not been achieved so far, in spite of numerous experimental attempts. Here, we obtain an unprecedented level of hydrogenation (≈90% of sp3 bonds) by exposing fully free-standing nanoporous samples─constituted by a single to a few veils of smoothly rippled graphene─to atomic hydrogen in ultrahigh vacuum. Such a controlled hydrogenation of high-quality and high-specific-area samples converts the original conductive graphene into a wide gap semiconductor, with the valence band maximum (VBM) ∼ 3.5 eV below the Fermi level, as monitored by photoemission spectromicroscopy and confirmed by theoretical predictions. In fact, the calculated band structure unequivocally identifies the achievement of a stable, double-sided fully hydrogenated configuration, with gap opening and no trace of π states, in excellent agreement with the experimental results.