Impact of substrate defects on the equilibrium one-dimensional island size distribution

As long as only first-neighbour interactions are considered, equilibrium island size distributions of monoatomic islands in one dimension follow an exponential law regardless of the strength and the repulsive or attractive character of the adsorbate–adsorbate interactions. However, one- dimensional atomic wires obtained via nucleation at the step edges have a monomodal island size distribution. In this paper, we present a simple one- dimensional Monte Carlo model that shows how the monomodal distribution observed experimentally can be obtained by including surface defects that only suppress the interaction between two successive adsorbates.Fil: Mirabella, D. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; ArgentinaFil: Aldao, Celso Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentin

Influence of interface potential on the effective mass in Ge nanostructures

The role of the interface potential on the effective mass of charge carriers is elucidated in this work. We develop a new theoretical formalism using a spatially dependent effective mass that is related to the magnitude of the interface potential. Using this formalism we studied Ge quantum dots (QDs) formed by plasma enhanced chemical vapour deposition (PECVD) and co-sputtering (sputter). These samples allowed us to isolate important consequences arising from differences in the interface potential. We found that for a higher interface potential, as in the case of PECVD QDs, there is a larger reduction in the effective mass, which increases the confinement energy with respect to the sputter sample. We further understood the action of O interface states by comparing our results with Ge QDs grown by molecular beam epitaxy. It is found that the O states can suppress the influence of the interface potential. From our theoretical formalism we determine the length scale over which the interface potential influences the effective mass

Inflammatory Abdominal Aortic Aneurysm (IAAA)

Purpose: The aim of this study is to report our experience about the inflammatory abdominal aortic aneurysm (IAAA). Methods: Between January 1999 and January 2008 we treated 8 cases of IAAA. Two patients underwent surgery in emergency. The preoperative diagnostic procedures were ultrasound (US), computed tomography (CT) and intravenous urography (IVU). In 6 elective patients the diagnosis of IAAA was obtained preoperatively. In one case a left hydroureteronephrosis was demonstrated by intravenous urography (IVU). All patients underwent open surgery with midline incision and transperitoneal access. Results: No 30-days mortality occurred. A case of pancreatitis was treated with conservative therapy. All patients had 60-days corticosteroid therapy. Conclusions: Our data suggest that because IAAA have the same rate of rupture of AAA, they need the same preventive treatment as non inflammatory abdominal aortic aneurysm (AAA) The kind of approach OPEN-EVAR should be chosen with the same criteria as AAA, even if EVAR teatment doesn't allow us to obtain the biopsy. Furthermore there are no sufficient evidences about regression of retroperitoneal fibrosis after EVAR treatment. Also the premature onset should be considered in the choice of treatment

Multilevel diabetic foot revascularization in COVID 19 patient: Case report

Introduction: Coronavirus 2019 (COVID-19) has been associated with endothelial dysfunction. This hypercoagulable state coming from the endothelial injury pones COVID-19 patients to a higher risk for thrombosis. COVID 19 diabetic patients are more exposed to peripheral vascular disease progression. Multilevel peripheral arterial disease is the main cause of critical limb ischemia. Vascular interventions are required to increase distal blood flow and reduce the risk of amputation. Presentation of case: We report a case of complex revascularization in a diabetic patient with aggressive right foot lesions evolution after COVID-19 infection. The patient presenting a Peripheral arterial ischemic involving the infrarenal aorta, iliac, femoral. The simultaneous intervention consisted of an endovascular aortic stent-graft placement and angioplasty of femoral artery. Discussion: Diabetes is a risk factor of severity and deaths in patients infected with pulmonary viruses. In our experience, COVID 19 virus can accelerate the ulcers generation and progression in diabetic patient. Hybrid interventions can be performed simultaneously or staged with benefit given by the complementary role of endovascular and surgical treatments. In the reported case, a complex simultaneous treatment in a patient presenting Multilevel peripheral arterial disease in association to COVID 19 infection was feasible in the same operation. Conclusion: Hybrid procedures are safe with high degree of efficacy in terms of revascularization, reduced morbidity and shorter intensive care. In our experience, the use of a hybrid procedure is technically feasible and allowed the treatment of complicated diabetic COVID-19 patient with a good outcome

Type 1A endoleak detachable coil embolization after endovascular aneurysm sealing: Case report

Introduction: Endovascular aneurysm sealing (EVAS) with the Nellix system was introduced to reduce endovascular aneurysm repair (EVAR) perioperative complications, especially endoleaks. Herein we report a case of successful type 1A endoleak managed with detachable coils embolization after EVAS. Presentation of case: A 77-year-old male was referred for abdominal pain. The angio-CT scan confirmed the previous EVAS procedure and showed a type Is2 endoleak below the right renal artery resulting in a 2.5 cm aortic blister with contrast medium filling the space between the aortic wall and the endobags. The patient was considered unfit for conventional open surgery and an endovascular approach with coil embolization Concerto Helix Detachable Coil System was chosen under local anesthesia. After intervention, a complete abdominal pain regression was registered. The 12- month CT follow-up showed endoleak sealing and Nellix system stability. Discussion: EVAS has been associated to a high endoleaks and complications incidence when compared to EVAR. The EVAS different device concept led to a different endoleak classification and management. Endoleak management main options include the Nellix system explantation or the Nellix in Nellix application, however these are nearly always not applicable, respectively, due to the high surgical risk condition and the Nellix system availability, especially in emergent setting. Despite the use of coil embolization is controversial, this tool is off-the-shelf and leads to a disease resolution in most of patients without other surgical options. Conclusion: Proximal type Is2 embolization after EVAS is feasible with limited invasiveness

Staged acute mesenteric and peripheral ischemia treatment in COVID-19 patient: Case report

Introduction: COVID-19 is an infectious disease that has been associated not only with respiratory complications. The COVID-19 disease includes, also damage to other organ systems as well as coagulopathy. The present report describes a case of COVID-19 presenting with acute mesenteric ischemia (AMI) and subsequent acute limb ischemia (ALI). Presentation of case: An 84-years old hospitalized female patient presenting diabetes and recent COVID-19 reported acute onset of abdominal pain and typical findings of AMI. The CT-angiography confirmed the AMI secondary to a superior mesenteric artery (SMA) occlusion. The patient was managed through an endovascular approach using a SMA mechanical thrombectomy and stenting with a good result. Discussion: Treatment of this life-threatening condition includes surgical resection of the necrotic bowel, restoration of blood flow to the ischemic intestine and supportive measure - gastrointestinal decompression, fluid resuscitation, hemodynamic support. Endovascular management of AMI is preferred over the standard surgical approach due to a reduced mortality and morbidity rates. Imaging findings of intestinal necrosis, however, represent an indication for AMI surgical treatment with explorative laparotomy. Different endovascular solutions have been employed to address AMI including mechanical thrombectomy, local thrombolysis, and PTA-stenting. Conclusion: COVID-19 clinical presentation can be atypical, including gastrointestinal symptoms. If a first embolic event occurs, an aggressive anticoagulation treatment could be inefficient to reduce the risk of subsequent embolization events. The limited life expectancy of such revascularization procedures should orientate towards less invasive treatments

How Organizational Resources and Managerial Features Affect Business Performance: An Analysis in the Greek Wine Industry

Despite the growing interest of the wine industry in quality and environmental certifications and the influence of these standards on positioning in international markets, scholarly research has paid proportionally limited attention to the link between winery export intensity and the adoption of internationally recognized standards. This study aims to analyze which factors make an organizational model performant, and to verify the impact of the adoption of third-party certifications on the export performance by using the resource-based view (RBV) theory as a theoretical lens. Findings show that younger wineries are more oriented towards the adoption of voluntary quality and environmental certifications, and they achieve the best economic performance, expressed in terms of overall turnover on the market. On the contrary, the better export performance is achieved by the largest group of wineries, which make the greatest effort in promotion and advertising activities and sell their products through intermediaries, while showing a low adoption of certifications. Our results have a number of theoretical and practical implications

Environmental Tobacco Smoke Exposure during Pregnancy and Child Neurodevelopment

The developing fetus is especially vulnerable to environmental toxicants, including tobacco constituents. The aim of this study was to assess the impact of environmental tobacco smoke (ETS) exposure during pregnancy on child neurodevelopment within the first two years of life. The study population consisted of 461 non-smoking pregnant women (saliva cotinine level <10 ng/mL). Maternal passive smoking was assessed based on the cotinine level in saliva analyzed by the use of high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-ESI + MS/MS) and by questionnaire data. The cotinine cut-off value for passive smoking was established at 1.5 ng/mL (sensitivity 63%, specificity 71%). Psychomotor development was assessed in children at the age of one- and two-years using the Bayley Scales of Infant and Toddler Development. Approximately 30% of the women were exposed to ETS during pregnancy. The multivariate linear regression model indicated that ETS exposure in the 1st and the 2nd trimesters of pregnancy were associated with decreasing child language functions at the age of one (β = -3.0, p = 0.03, and β = -4.1, p = 0.008, respectively), and two years (β = -3.8, p = 0.05, and β = -6.3, p = 0.005, respectively). A negative association was found for cotinine level ≥1.5 ng/mL in the 2nd trimester of pregnancy and child cognition at the age of 2 (β = -4.6, p = 0.05), as well as cotinine levels ≥1.5 ng/mL in all trimesters of pregnancy and child motor abilities at two years of age (β = -3.9, p = 0.06, β = -5.3, p = 0.02, and β = -4.2, p = 0.05, for the 1st, the 2nd, and the 3rd trimester of pregnancy, respectively; for the 1st trimester the effect was of borderline statistical significance). This study confirmed that ETS exposure during pregnancy can have a negative impact on child psychomotor development within the first two years of life and underscore the importance of public health interventions aiming at reducing this exposure