An investigation into the effects of partial discharge activity in sulphurhexafluoride gas on liquid insulation

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering Johannesburg 1992The purpose of the work presented here was to investigate the affects of SPg gas present in insulating liquids. This research was carried out mainly by means of experimental work. Investigations involving the gas evolving or absorbing properties of air and SFg saturated ins;'ating liquids were carried out. These tests showed that the liquids investigated (transformer oil and silicone liquid) were capable of absorbing large amounts of SFg. Further experiments were performed to discover what influence this would have on stressed, enclosed liquid samples with air gaps above them. In addition to this, partial discharges in gas bubbles trapped behind paper insulation were investigated under high voltage stresses. These comparative experiments were done using SFg and N; bubbles. The results obtained have provided evidence that SFg present in liquid insulation is not deleterious to the insulation when compared with the presence of non electronegative gasses

Go/rGo as reinforcing nanofiller in carbon fiber/epoxy resin composite systems

Interfacial interactions between matrix and reinforcement of composites influences greatly in final properties of the material. Carbon Fibers are characterized for to have low interactions with resins when forming a composite material. In the present study, 0.3 wt% of GO/rGO were incorporated in three systems of epoxy resin/carbon fiber as reinforcing fillers, trying to profit the chemical affinity between aromatics structures of GO/rGO and polar interactions with epoxy resin. GO/rGO were characterized by XPS, TGA was performed on carbon fiber, epoxy resins and composites obtained and SEM was utilized to observe composite samples in detail once mechanical tests were conducted. Composites experienced noticeable enhancements by employing Bisphenol Epoxy (BP) cured with methyl cyclohexane-1,2-dicarboxylic anhydride (MCHDA) as matrix and carbon fiber of 300 g/cm2 as reinforcement; Youngs modulus, rupture stress and elongation to fail- ure increased almost twofold compared to non-modified composites by adding GO in the system and even superior boosts can be appreciated with rGO, which additionally improves the flexural stress from 14.6 to 30.1 GPa.Postprint (published version

GO/rGO as reinforcing nanofiller in aramid fiber/epoxy resin composite systems

Compatibility between matrix and reinforcement plays an important role in final properties of composite materials, which is why many works are focused in modify- ing interfacial interactions between both components to achieve greater mechanical properties. In the present study, 0.3 wt% of GO/rGO particles are introduced in epoxy resin/aramid fiber composites to evaluate the capacity of GO/rGO as reinforcing fillers. XPS, SEM, TGA, tensile and flexural tests are utilized to characterize GO/rGO, aramid fiber, three epoxy resin matrix systems and all composites obtained. Enhancements of mechanical properties up to 80 % were achieved by combining digly- cidyl ether bisfenol A (DGEBA) + diglycidyl aniline (DGA) + m-xylendiamine matrix, aramid fiber reinforcement and GO/rGO.Postprint (published version

Degenerative Jargon Aphasia: Unusual Progression of Logopenic/Phonological Progressive Aphasia?

Primary progressive aphasia (PPA) corresponds to the gradual degeneration of language which can occur as nonfluent/agrammatic PPA, semantic variant PPA or logopenic variant PPA. We describe the clinical evolution of a patient with PPA presenting jargon aphasia as a late feature. At the onset of the disease (ten years ago) the patient showed anomia and executive deficits, followed later on by phonemic paraphasias and neologisms, deficits in verbal short-term memory, naming, verbal and semantic fluency. At recent follow-up the patient developed an unintelligible jargon with both semantic and neologistic errors, as well as with severe deficit of comprehension which precluded any further neuropsychological assessment. Compared to healthy controls, FDG-PET showed a hypometabolism in the left angular and middle temporal gyri, precuneus, caudate, posterior cingulate, middle frontal gyrus, and bilaterally in the superior temporal and inferior frontal gyri. The clinical and neuroimaging profile seems to support the hypothesis that the patient developed a late feature of logopenic variant PPA characterized by jargonaphasia and associated with superior temporal and parietal dysfunction

Pathological and clinical features of multiple cancers and lung adenocarcinoma: a multicentre study

OBJECTIVES: Lung cancer is increasingly diagnosed as a second cancer. Our goal was to analyse the characteristics and outcomes of early-stage resected lung adenocarcinomas in patients with previous cancers (PC) and correlations with adenocarcinoma subtypes.METHODS: We retrospectively reviewed data of patients radically operated on for stage I-II lung adenocarcinoma in 9 thoracic surgery departments between 2014 and 2017. Overall survival (OS) and time to disease relapse were evaluated between subgroups.RESULTS: We included 700 consecutive patients. PC were present in 260 (37.1%). Breast adenocarcinoma, lung cancer and prostate cancer were the most frequent (21.5%, 11.5% and 11.2%, respectively). No significant differences in OS were observed between the PC and non-PC groups (P = 0.378), with 31 and 75 deaths, respectively. Patients with PC had smaller tumours and were more likely to receive sublobar resection and to be operated on with a minimally invasive approach. Previous gastric cancer (P = 0.042) and synchronous PC (when diagnosed up to 6 months before lung adenocarcinoma; P = 0.044) were related, with a worse OS. Colon and breast adenocarcinomas and melanomas were significantly related to a lower incidence of high grade (solid or micropapillary, P = 0.0039, P = 0.005 and P = 0.028 respectively), whereas patients affected by a previous lymphoma had a higher incidence of a micropapillary pattern (P = 0.008).CONCLUSIONS: In patients with PC, we found smaller tumours more frequently treated with minimally invasive techniques and sublobar resection, probably due to a more careful follow-up. The impact on survival is not uniform and predictable; however, breast and colon cancers and melanoma showed a lower incidence of solid or micropapillary patterns whereas patients with lymphomas had a higher incidence of a micropapillary pattern

Impact of High‑Grade Patterns in Early‑Stage Lung Adenocarcinoma: A Multicentric Analysis

Objective The presence of micropapillary and solid adenocarcinoma patterns leads to a worse survival and a signifcantly higher tendency to recur. This study aims to assess the impact of pT descriptor combined with the presence of high-grade components on long-term outcomes in early-stage lung adenocarcinomas. Methods We retrospectively collected data of consecutive resected pT1-T3N0 lung adenocarcinoma from nine European Thoracic Centers. All patients who underwent a radical resection with lymph-node dissection between 2014 and 2017 were included. Diferences in Overall Survival (OS) and Disease-Free Survival (DFS) and possible prognostic factors associated with outcomes were evaluated also after performing a propensity score matching to compare tumors containing non-highgrade and high-grade patterns. Results Among 607 patients, the majority were male and received a lobectomy. At least one high-grade histological pattern was seen in 230 cases (37.9%), of which 169 solid and 75 micropapillary. T1a-b-c without high-grade pattern had a signifcant better prognosis compared to T1a-b-c with high-grade pattern (p=0.020), but the latter had similar OS compared to T2a (p=0.277). Concurrently, T1a-b-c without micropapillary or solid patterns had a signifcantly better DFS compared to those with high-grade patterns (p=0.034), and it was similar to T2a (p=0.839). Multivariable analysis confrms the role of T descriptor according to high-grade pattern both for OS (p=0.024; HR 1.285 95% CI 1.033–1.599) and DFS (p=0.003; HR 1.196, 95% CI 1.054–1.344, respectively). These results were confrmed after the propensity score matching analysis. Conclusions pT1 lung adenocarcinomas with a high-grade component have similar prognosis of pT2a tumors

Riduzione delle emissioni di ammoniaca nell’agricoltura mediterranea attraverso tecniche innovative di fertirrigazione con liquami (LIFE16 ENV/ES/000400)

Esta publicación ha sido elaborada como resultado de los trabajos realizados dentro del proyecto LIFE ARIMEDA: Reducción de emisiones de amoníaco en la agricultura mediterránea a través de técnicas innovadoras de fertirrigación con purín (LIFE16 ENV/ES/000400). El proyecto LIFE ARIMEDA ha recibido fondos del Programa LIFE de la Unión Europea.Publishe

Acute Delta Hepatitis in Italy spanning three decades (1991–2019): Evidence for the effectiveness of the hepatitis B vaccination campaign

Updated incidence data of acute Delta virus hepatitis (HDV) are lacking worldwide. Our aim was to evaluate incidence of and risk factors for acute HDV in Italy after the introduction of the compulsory vaccination against hepatitis B virus (HBV) in 1991. Data were obtained from the National Surveillance System of acute viral hepatitis (SEIEVA). Independent predictors of HDV were assessed by logistic-regression analysis. The incidence of acute HDV per 1-million population declined from 3.2 cases in 1987 to 0.04 in 2019, parallel to that of acute HBV per 100,000 from 10.0 to 0.39 cases during the same period. The median age of cases increased from 27 years in the decade 1991-1999 to 44 years in the decade 2010-2019 (p < .001). Over the same period, the male/female ratio decreased from 3.8 to 2.1, the proportion of coinfections increased from 55% to 75% (p = .003) and that of HBsAg positive acute hepatitis tested for by IgM anti-HDV linearly decreased from 50.1% to 34.1% (p < .001). People born abroad accounted for 24.6% of cases in 2004-2010 and 32.1% in 2011-2019. In the period 2010-2019, risky sexual behaviour (O.R. 4.2; 95%CI: 1.4-12.8) was the sole independent predictor of acute HDV; conversely intravenous drug use was no longer associated (O.R. 1.25; 95%CI: 0.15-10.22) with this. In conclusion, HBV vaccination was an effective measure to control acute HDV. Intravenous drug use is no longer an efficient mode of HDV spread. Testing for IgM-anti HDV is a grey area requiring alert. Acute HDV in foreigners should be monitored in the years to come