Validation of the Electromagnetic Physical Processes with Software SPENVIS

The Space Radiation represents a serious risk for astronauts during space missions. The risk related to the space radiation exposure could involve acute and/or late effects. The Solar Cosmic Radiation that consists of protons (≈98%) with a very wide spectrum in energy (up to several GeV), is the major source of exposure for the crew. In this paper we present the results of the validation of the electromagnetic physical processes with the aim to contribute to the study of radiation protection for astronauts, in particular against the radiation due to the Solar Particle Events (SPE). The simulation was performed using MULASSIS, a module to the software SPENVIS, with protons as source, in the energy range from 800 MeV to 1.2 GeV, on a slab of aluminum of mass thickness of 20 g/cm2. The results obtained by the simulation were compared with PSTAR database of the NIST. Finally, a comparison between SPENVIS and Geant4-9.6p2 was performed

Clinical predictive factors of pathologic complete response in locally advanced rectal cancer

Background: Predictive factors of pathologic complete response (pCR) after neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC) are still not identified. The purpose of this study was to define them. Materials and Methods: Data from consecutive LARC patients treated between January 2008 and June 2014 at our Institution were included in the analysis. All patients were treated with a long course of nCRT. Demographics, initial diagnosis and tumor extension details, as well as treatment modalities characteristics were included in the univariate and logistic regression analysis. Results: In total 99 patients received nCRT, of whom 23 patients (23.2%) achieved pCR. Patients with and without pCR were similar in term of age, sex, comobidities, BMI and tumor characteristics. Multivariate logistic regression indicated that pre-treatment tumor size <= 5 cm was a significant predictor for pCR (p = 0.035), whereas clinical N stage only showed a positive trend (p = 0.084). Conclusions: Tumor size at diagnosis could be used to predict pCR, and thus to individualize therapy in LARC patients management. Validation in other studies is needed

Study of Surface Emissions of 220Rn (Thoron) at Two Sites in the Campi Flegrei Caldera (Italy) during Volcanic Unrest in the Period 2011–2017

The study concerns the analysis of 220Rn (thoron) recorded in the surface soil in two sites of the Campi Flegrei caldera (Naples, Southern Italy) characterized by phases of volcanic unrest in the seven-year period 1 July 2011–31 December 2017. Thoron comes only from the most surface layer, so the characteristics of its time series are strictly connected to the shallow phenomena, which can also act at a distance from the measuring point in these particular areas. Since we measured 220Rn in parallel with 222Rn (radon), we found that by using the same analysis applied to radon, we obtained interesting information. While knowing the limits of this radioisotope well, we highlight only the particular characteristics of the emissions of thoron in the surface soil. Here, we show that it also shows some clear features found in the radon signal, such as anomalies and signal trends. Consequently, we provide good evidence that, in spite of the very short life of 220Rn compared to 222Rn, both are related to the carrier effect of CO2, which has significantly increased in the last few years within the caldera. The hydrothermal alterations, induced by the increase in temperature and pressure of the caldera system, occur in the surface soils and significantly influence thoron's power of exhalation from the surface layer. The effects on the surface thoron are reflected in both sites, but with less intensity, the same behavior of 222Rn following the increasing movements and fluctuations of the geophysical and geochemical parameters (CO2 flux, fumarolic tremor, background seismicity, soil deformation). An overall linear correlation was found between the 222−220Rn signals, indicating the effect of the CO2 vector. The overall results represent a significant step forward in the use and interpretation of the thoron signal

Laparoscopic treatment of splenic artery aneurysms

OBJECTIVES: The purpose of this study was to report a series of 16 consecutive patients who underwent laparoscopic treatment of splenic artery aneurysms. METHODS: Over a period of 8 years, patients were selected for the laparoscopic option by a team of specialists that included the vascular surgeon, the interventional radiologist, and the laparoscopic surgeon. The mean size of the aneurysm was 32 mm and most was located at the splenic hilum. They were twice as common in females as in males. Ultrasonography with color Doppler function was used to define intraoperative strategy. RESULTS: The laparoscopic treatment entailed excision of the aneurysm or its exclusion, usually reserved for distally located lesions. In one patient, laparoscopic resection and robotic anastomosis of the splenic artery was performed to re-establish flow to the spleen. In two patients, the intraoperative decision was added to combine a laparoscopic splenectomy due to insufficient residual arterial flow to the spleen. There was no conversion, or need for re-operation or related mortality. Analysis of intraoperative arterial flow data avoided unnecessary splenectomy following noncritical reduction of flow to the spleen. CONCLUSIONS: The use of intraoperative color Doppler ultrasonography is essential in deciding the appropriate procedure and whether the spleen should be removed or saved. Early control of the splenic artery proximal to the aneurysm can limit the risk of conversion due to intraoperative bleeding. Distally located aneurysms are more difficult to manage and entail a higher risk of associated splenectomy. The laparoscopic option offers some advantages over the endovascular treatment in selected patients. A multidisciplinary approach is the key to a successful treatment of this uncommon disease

Nomex with boron as a neutron shielding in space: Preliminary study

In this work we present a study devoted to the evaluation of the efficiency of a radiation shield, made out of the Nomex material doped with boron, in reducing the absorbed dose after bombardment with a 1GeV proton beam. This study is relevant to the definition of optimal conditions for the shielding of astronauts from Solar Particle Events and Galactic Cosmic Radiation in space. Nomex shield is treated with boron at different concentrations. The production and transport of radiation produced after proton interaction is treated with a simulation tool based on Geant4. The added boron acts as an effective neutron mitigating material. The main preliminary result is that the average dose changes effectively despite the additional production of alpha particles from the reaction 10B(n,α)

Hiperfluxo portal na forma hepatosplênica da esquistossomose mansônica

PURPOSE: The purpose of this study was to assess portal hemodynamics in patients with portal hypertension due to hepatosplenic schistosomiasis as well as to assess the contribution of splanchnic hyperflow to the pathophysiology of the portal hypertension. METHODS: Sixteen patients with schistosomal portal hypertension and previous history of upper digestive bleeding due to esophageal varices rupture underwent elective esophagogastric devascularization and splenectomy and were prospectively studied. All patients underwent intraoperative invasive hemodynamic portal monitoring with a 4F-thermodilution catheter. The intraoperative portal hemodynamic assessment was conducted after laparotomy (initial) and after esophagogastric devascularization (final). RESULTS: The initial portal pressure was elevated (mean 28.5 ± 4.5 mm Hg), and a significant drop of 25% was observed at the end of the surgery (21.9 ± 4.9 mm Hg). The initial portal flow was elevated (mean 1766.9 ± 686.6 mL/min). A significant fall (42%) occurred at the end of the surgical procedure (1025.62 ± 338.7 mL/min). Fourteen patients (87.5%) presented a portal flow of more than 1200 mL/min, and in 5 cases, values greater than 2000 mL/min were observed. CONCLUSIONS: Esophagogastric devascularization and splenectomy promote a significant reduction of the elevated portal pressure and flow in schistosomal portal hypertension. These data favor the hypothesis of portal hyperflow in the physiopathology of portal hypertension of schistosomiasis.OBJETIVOS: o objetivo do presente estudo é estudar a hemodinâmica portal em pacientes com hipertensão portal secundária a forma hepatoesplênica da esquistossomose e avaliar a contribuição do hiperfluxo esplênico na sua fisiopatologia CASUÍSTICA E MÉTODOS: Foram estudados prospectivamente 16 pacientes portadores de hipertensão portal secundária à forma hepatoesplênica da esquistossomose mansônica com indicação de tratamento cirúrgico. Todos foram submetidos a avaliação hemodinâmica portal com cateter de termodiluição 4F antes e após a realização de desvascularização esofago-gástrica com esplenectomia. RESULTADOS: Na avaliação intra-operatória inicial observou-se pressão (28,5 + 4,5 mmHg ) e fluxo (1750,59 ± 668,14 ml/min) portais iniciais bem acima dos valores considerados normais. Houve queda significante de 25% na pressão (21,65 ± 5,55 mmHg ) e de 42% no fluxo (1011,18 ± 332,73 ml/min) ao término da cirurgia. Quatorze pacientes (87.5%) apresentavam fluxo portal superior a 1200 ml/min e, em 5 casos, valores superiores a 2000 ml/min foram observados. CONCLUSÕES: A pressão e o fluxo portais estão aumentados na hipertensão portal esquistossomótica. A desvascularização esofago-gástrica com esplenectomia reduz significativamente tanto a pressão quanto o fluxo portais. Estes dados favorecem a hipótese do hiperfluxo esplâncnico (esplênico e mesentérico) na fisiopatologia da hipertensão portal na esquistossomose forma hepatoesplênica

High colouring efficiency, optical density and inserted charge in sol–gel derived electrochromic titania nanostructures

A pure TiO2 thin film (100–120 nm) was made from a green aqueous sol–gel precursor on FTO glass and calcined at 430 °C. It was a mix of amorphous, anatase, rutile and brookite TiO2 phases, and exhibited very good electrochromic properties over visible and NIR wavelengths with an applied bias of +0.1 V to −1.5 V. It was highly transparent showing excellent coloration with applied voltage, with transmittance modulation (ΔT) = 69.7% at 550 nm, 86% at 700 nm and an overall ΔT between 400–1650 nm of 60%, giving a very large change in optical density (ΔOD) of 1.4 at 550 nm and 2.4 at 700 nm. Cyclic voltammograms had typical peaks for TiO2 at −1.3 V for colouration and −0.9 V for bleaching, with a high separation of 0.37 V between peaks, and a charge density after charging for 25 min of Qc = 50 mC cm−2. After only 60 s and 120 s at −1.5 V, inserted charge values of 17.6 and 22 mC cm−2 were observed, leading to a high colouration efficiency (CE) of 55.9 cm2 C−1 at 550 nm. These ΔOD, ΔT, Qc and CE values are superior to any previously reported for crystalline sol–gel TiO2 films. They also possessed rapid switching times for bleaching and colouring of τb90% = 10 s and τc90% = 55 s, comparable to the best previously reported sol–gel anatase-based TiO2 films. This makes this nanomaterial an excellent candidate for smart windows and other electrochromic devices and applications

Unshrouded plate fin heat sinks for electronics cooling: Validation of a comprehensive thermal model and cost optimization in semi-active configuration

Plate Fin Heat Sinks (PFHS) are among the simplest and most widespread devices for electronics cooling. Because of the many design parameters to be considered, developing both cost and thermal effective PFHS is a critical issue. Here, a novel thermal model of PFHS is presented. The model has a broad field of applicability, being comprehensive of the effects of flow bypass, developing boundary layers, fin efficiency and spreading resistance. Experiments are then carried out to validate the proposed thermal model, and its good accuracy is demonstrated. Finally, an optimization methodology based on genetic algorithms is proposed for a cost-effective selection of the design parameters of PFHS, which is particularly effective with semi-active configurations. Such an optimization methodology is then tested on a commercial heat sink, resulting in a possible 53% volume reduction at fixed thermal performances

Malignant hypertension and hyperreninemia: primary or secondary hypertension? A case report

Malignant hypertension is a rare condition characterized by severe hypertension and multi-organ ischemic damage. Marked activation of the renin-angiotensin system is observed in many patients, but its persistence over time is not known. We report a case of a 42-year-old woman who presented with severe hypertension and multi-organ damage. Initial evaluation showed an elevated value of direct renin concentration with normal plasma aldosterone concentration and a nodular lesion in the left adrenal gland. The differential diagnosis between the primary and secondary form of hypertension had to be questioned. Consequently, the patient was followed up for 20 months. Repeated checks showed a significant increase in renin levels with a normal aldosterone concentration and regression of organ damage. After 20 months, renin values returned within normal range. Hyperreninemia persisting over a long period of time has not been fully explained. Long-term follow-up allowed us to attribute malignant hypertension to de novo essential hypertension