How kinetics drives the two- to three-dimensional transition in semiconductor strained heterostructures: the case of InAs/GaAs(001)

The two- to three-dimensional growth transition in the InAs/GaAs(001) heterostructure has been investigated by atomic force microscopy. The kinetics of the density of three dimensional quantum dots evidences two transition thresholds at 1.45 and 1.59 ML of InAs coverage, corresponding to two separate families, small and large. Based on the scaling analysis, such families are characterized by different mechanisms of aggregation, involving the change of the critical nucleus size. Remarkably, the small ones give rise to a wealth of "monomers" through the erosion of the step edges, favoring the explosive nucleation of the large ones.Comment: 10 pages, 3 figures. Submitted to Phys. Rev. Let

Experimental and Numerical Studies on a Centrifugal Pump with 2D-Curved Blades in Cavitating Condition

In the presented study a special test-pump with 2D curvature blade geometry in cavitating and non-cavitating conditions was investigated using different experimental techniques and a 3D numerical model of cavitating flows. Experimental and numerical results concerning pump characteristics and performance breakdown were compared at different flow conditions. Appearing types of cavitation and the spatial distribution of vapour structures within the runner were also analysed

Early cross-sectional imaging following open and laparoscopic cholecystectomy : a primer for radiologists

Abstract: Performed on either an elective or urgent basis, cholecystectomy currently represents the most common abdominal operation due to the widespread use of laparoscopy and the progressively expanded indications. Compared to traditional open surgery, laparoscopic cholecystectomy minimised the duration of hospitalisation and perioperative mortality. Albeit generally considered safe, cholecystectomy may result in adverse outcomes with non-negligible morbidity. Furthermore, the incidence of worrisome haemorrhages and biliary complications has not been influenced by the technique shift. Due to the growing medico-legal concerns and the vast number of cholecystectomies, radiologists are increasingly requested to investigate recently operated patients. Aiming to increase familiarity with post-cholecystectomy cross-sectional imaging, this paper provides a brief overview of indications and surgical techniques and illustrates the expected early postoperative imaging findings. Afterwards, most iatrogenic complications following open, converted, laparoscopic and laparo-endoscopic rendezvous cholecystectomy are reviewed with examples, including infections, haematoma and active bleeding, residual choledocholithiasis, pancreatitis, biliary obstruction and leakage. Multidetector computed tomography (CT) represents the \u201cworkhorse\u201d modality to rapidly investigate the postoperative abdomen in order to provide a reliable basis for an appropriate choice between conservative, interventional or surgical treatment. Emphasis is placed on the role of early magnetic resonance cholangiopancreatography (MRCP) and additional gadoxetic acid-enhanced MRCP to provide a non-invasive anatomic and functional assessment of the operated biliary tract. Teaching Points: \u2022 Having minimised perioperative mortality and hospital stay, laparoscopy has now become the first-line approach to performing cholecystectomy, even in patients with acute cholecystitis. \u2022 Laparoscopic, laparo-endoscopic rendezvous, converted and open cholecystectomy remain associated with non-negligible morbidity, including surgical site infections, haemorrhage, residual lithiasis, pancreatitis, biliary obstruction and leakage. \u2022 Contrast-enhanced multidetector computed tomography (CT) is increasingly requested early after cholecystectomy and represents the \u201cworkhorse\u201d modality that rapidly provides a comprehensive assessment of the operated biliary tract and abdomen. \u2022 Magnetic resonance cholangiopancreatography (MRCP) is the best modality to provide anatomic visualisation of the operated biliary tract and is indicated when biliary complications are suspected. \u2022 Additional gadoxetic acid (Gd-EOB-DTPA)-enhanced MRCP non-invasively provides functional biliary assessment, in order to confirm and visualise bile leakage

Early outcome of anatomical lung resection for non-small cell lung cancer in the elderly

OBJECTIVE Surgery is the mainstay of early-stage lung cancer treatment. However, since life expectancy is constantly increasing, we wanted to investigate whether this principle also applies to elderly (≥70-year-old) patients. PATIENTS AND METHODS We analyzed a prospectively maintained database on anatomical lung resections at our institute. Patients were divided in two groups: <70 years and ≥70 years (elderly). Outcome indicators were postoperative cardiopulmonary complications rate and 30-day readmission rate. Baseline and surgical characteristics were compared by mean of t-test, Mann-Whitney U test, chi2 and Fisher exact tests. Propensity score matching was performed to account for differences between groups in the outcome's analysis. RESULTS We selected 241 patients with lung cancer (2017-2021) who underwent anatomical lung resections. Median age was 70.5 (IQR: 64-76). 133 patients (54%) aged 70 and above. Patients and surgical characteristics (comorbidities, lung function, performance status, type and extension of lung resection and surgical approach) were similar among groups, except for atrial fibrillation (p=0.01) and previous cancer history (p<0.0001) which were more frequent in the elderly group. Non-elderly patients were more frequently active smokers (p<0.0001). Cardiopulmonary complications rate was 23%, 30-day readmission rate was 12.6%. We did not observe any significant difference in all the short-term outcome indicators between the elderly and the younger counterpart. Particularly, complications rate (p=0.91) and 30-day readmission (p=0.84) did not differ between groups. CONCLUSIONS In our series, short-term outcomes are not compromised in elderly patients. The evolution in surgical strategy and expertise contribute to offer surgical resection with curative intent for lung cancer to a large spectrum of patients

Nanostructured Lead Electrodes with Reduced Graphene Oxide for High-Performance Lead–Acid Batteries

Nanostructured Pb electrodes consisting of nanowire arrays were obtained by electrodeposition, to be used as negative electrodes for lead–acid batteries. Reduced graphene oxide was added to improve their performances. This was achieved via the electrochemical reduction of graphene oxide directly on the surface of nanowire arrays. The electrodes with and without reduced graphene oxide were tested in a 5 M sulfuric acid solution using a commercial pasted positive plate and an absorbed glass mat separator in a zero-gap configuration. The electrodes were tested in deep cycling conditions with a very low cut-off potential. Charge–discharge tests were performed at 5C. The electrode with reduced graphene oxide outperformed the electrode without reduced graphene oxide, as it was able to work with a very high utilization of active mass and efficiency. A specific capacity of 258 mAhg−1–very close to the theoretical one–was achieved, and the electrode lasted for more than 1000 cycles. On the other hand, the electrode without reduced graphene oxide achieved a capacity close to 230 mAhg−1, which corresponds to a 90% of utilization of active mass

Domain Walls and Metastable Vacua in Hot Orientifold Field Theories

We consider "Orientifold field theories", namely SU(N) gauge theories with Dirac fermions in the two-index representation at high temperature. When N is even these theories exhibit a spontaneously broken Z2 centre symmetry. We study aspects of the domain wall that interpolates between the two vacua of the theory. In particular we calculate its tension to two-loop order. We compare its tension to the corresponding domain wall in a SU(N) gauge theory with adjoint fermions and find an agreement at large-N, as expected from planar equivalence between the two theories. Moreover, we provide a non-perturbative proof for the coincidence of the tensions at large-N. We also discuss the vacuum structure of the theory when the fermion is given a large mass and argue that there exist N-2 metastable vacua. We calculate the lifetime of those vacua in the thin wall approximation.Comment: 29 pages, 4 figures. v2: minor changes in the introduction section. to appear in JHE

Experimental and numerical studies on a centrifugal pump with 2D-curved blades in cavitation condition

In the presented study a special test-pump with 2D curvature blade geometry in cavitating and non-cavitating conditions was investigated using different experimental techniques and a 3D numerical model of cavitating flows. Experimental and numerical results concerning pump characteristics and performance breakdown were compared at different flow conditions. Appearing types of cavitation and the spatial distribution of vapour structures within the runner were also analysed

Gd-EOB-DTP-enhanced MRC in the preoperative percutaneous management of intra and extrahepatic biliary leakages: Does it matter?

Postoperative bile leakage is a common complication of abdominal surgical procedures and a precise localization of is important to choose the best management. Many techniques are available to correctly identify bile leaks, including ultrasound (US), computed tomography (CT) or magnetic resonance imaging (MRI), being the latter the best to clearly depict "active" bile leakages. This paper presents the state of the art algorithm in the detection of biliary leakages in order to plan a percutaneous biliary drainage focusing on widely available and safe contrast agent, the Gb-EOB-DPA. We consider its pharmacokinetic properties and impact in biliary imaging explain current debates to optimize image quality. We report common sites of leakage after surgery with special considerations in cirrhotic liver to show what interventional radiologists should look to easily detect bile leaks