Single-center experience in the treatment of visceral artery aneurysms

Background: Visceral artery aneurysms (VAAs), although rare, represent a life-threatening disease with high mortality rates. With the more frequent use of diagnostic tests, there has been an incidental detection of these lesions which are mostly asymptomatic. It follows that surgeons are increasingly called to decide on the most appropriate management of VAAs between an open surgical or endovascular approach and among the different endovascular options currently available. The aim of this retrospective study was to evaluate the results of open surgery and interventional endovascular strategies of visceral artery aneurysms with respect to technical success, therapy-associated complications, and postinterventional follow-up in the elective and emergency situation. Methods: From January 1992 to January 2017, 125 open surgical or endovascular interventions for VAA were performed at our institution. Once the VAA was diagnosed and the indication for treatment was assessed, the preoperative diagnostic work-up consisted of contrast computed tomography (CT) or magnetic resonance imaging (MRI) and, in some patients, digital subtraction angiography. Follow-up included clinical and duplex ultrasound scan (DUS) and contrast-enhanced ultrasound to assess the treated vessel patency and organ perfusion after 1, 6, and 12 months, and yearly thereafter. CT or MRI controls were also performed at 1 year of follow-up and only when DUS was not diagnostic or showed a complication thereafter. After the first 5 years of follow-up, the status of the patient was obtained by a structured telephone survey. Results: The treatment option was endovascular in 56 of 125 cases (44.8%). Technical success was 98.3%. In one case, the procedure was interrupted for the extensive dissection of the afferent vessel. Twenty-six patients were treated by coil embolization while 29 with covered stenting. The endovascular approach was in emergency in two cases (3.6%). In the endovascular group, mortality was nil. Complications occurred in 5 cases (8.9%): 1 subacute intestinal ischemia caused by superior mesenteric artery dissection, 2 aneurysm reperfusion, 1 stent thrombosis, and 1 massive splenic hematoma. In 69 (55.2%) cases, surgical treatment was preferred, with 24 VAA resections and 45 arterial reconstructions. In 20 cases (29%), open surgery was performed in emergency conditions. In the surgical group, 8 emergency patients (40%) died intraoperatively. The mortality after elective surgical interventions was nil. Complications after surgery were 4 graft late thrombosis (5.8%): asymptomatic in three cases and requiring splenectomy in one. Conclusions: There is no overall consensus regarding the indications for treatment of VAA. Currently in emergent setting, the endovascular approach should be considered as the first choice because of its reduced invasiveness, faster way to access and bleeding control; this accounts for the lower morality of the interventional therapy than open surgery. Endovascular approach is effective for elective repair of VAAs, but procedure-related complications may occur in a not negligible number of patients. Given comparable mortality rates and low procedure-related complication rate, surgical approach still has space in the elective management of VAAs, especially for aneurysms unsuitable or challenging for the endovascular option in patients with low surgical risk. The size, location, and morphology of VAAs, systemic or local comorbidities, and specific anatomical situations such as previous abdominal surgery should dictate treatment choice

Response of the Arctic Pteropod Limacina helicina to projected future environmental conditions

Thecosome pteropods (pelagic mollusks) can play a key role in the food web of various marine ecosystems. They are a food source for zooplankton or higher predators such as fishes, whales and birds that is particularly important in high latitude areas. Since they harbor a highly soluble aragonitic shell, they could be very sensitive to ocean acidification driven by the increase of anthropogenic CO2 emissions. The effect of changes in the seawater chemistry was investigated on Limacina helicina, a key species of Arctic pelagic ecosystems. Individuals were kept in the laboratory under controlled pCO2 levels of 280, 380, 550, 760 and 1020 matm and at control (0uC) and elevated (4uC) temperatures. The respiration rate was unaffected by pCO2 at control temperature, but significantly increased as a function of the pCO2 level at elevated temperature. pCO2 had no effect on the gut clearance rate at either temperature. Precipitation of CaCO3, measured as the incorporation of 45Ca, significantly declined as a function of pCO2 at both temperatures. The decrease in calcium carbonate precipitation was highly correlated to the aragonite saturation state. Even though this study demonstrates that pteropods are able to precipitate calcium carbonate at low aragonite saturation state, the results support the current concern for the future of Arctic pteropods, as the production of their shell appears to be very sensitive to decreased pH. A decline of pteropod populations would likely cause dramatic changes to various pelagic ecosystems

Carbon fluxes in coral reefs. II. Eulerian study of inorganic carbon dynamics and measurement of air-sea CO₂ exchanges

Air-sea CO2 exchanges and the partial pressure of CO2 were measured in surface water overlying 2 coral reefs: Moorea (French Polynesia, austral winter, August 1992), where coral diversity and surface cover are low, and Yonge Reef (Great Barrier Reef, austral summer, December 1993), where coral diversity and cover are comparatively higher. A procedure is proposed to estimate the potential CO2 exchange with the atmosphere by taking into account both the saturation level of oceanic seawater and the equilibration process occurring after water leaves the reef. It is shown that both sites were net sources of CO2 to the atmosphere as a result of the effect of calcification on the dynamics of the inorganic carbon system. The potential global CO2 evasion from the ocean to the atmosphere is about 4 times higher at Yonge Reef than at Moorea. It is also demonstrated that, at both sites, the major exchange of CO2 from sea to air occurs as seawater returns to chemical equilibrium after it has crossed and left the reef. The dynamics of inorganic carbon were studied using the so-called homogeneous buffer factor [beta = dln(pCO(2))/dln(DIC)] (where pCO(2) is the CO2 partial pressure in surface water and DIC is dissolved inorganic carbon), which gave estimates that approximately 80% of the change in inorganic carbon was related to photosynthesis and respiration. This approach showed that the calcification rate was proportional to the net organic production during the day and to the respiration rate at night

Computer Controlled Solid State Lighting Assembly to Emulate Diurnal Cycle and Improve Circadian Rhythm Control

A light system can simultaneously emulate more than one different diurnal cycle to individually improve circadian rhythm control for more than one observer by having each light fixture autonomously self-controlled. Each light fixture is mountable in respective locations to individually treat respective observers. Each light fixture includes one or more light elements mounted to a housing and are controllable to emit a selected light intensity at a selected light temperature. A micro controller is contained in the housing and includes memory containing instructions for one or more automatic diurnal cycle protocols. The micro controller is in communication with the memory and the one or more light elements to execute the instructions to configure the light fixture to vary the light intensity and the light temperature of the emitted light

Hot, Sour and Breathless – Ocean under Stress.

ISBN 978-0-9519618-6-

GNSS-based Location Determination System Architecture for railway performance assessment in presence of local effects

GNSS plays a strategic role on the introduction of the Virtual Balise functionality and the train integrity. Thanks to GNSS, it could be possible to realize cost effective solutions to increase the safety in the regional lines, where the traffic density is lower. The train position estimation is implemented taking into account that the train is constrained to lie on the track (i.e. track constraint). In this way, we can express the position in terms of the curvilinear abscissa (progressive mileage) of the track corresponding to the train position. However, the impact of local effects such as multipath, foliage attenuation and shadowing in the railway environment plays a crucial role due to the presence of infrastructures like platform roofs, side walls, tunnel entrances, buildings and so on close to the trackside. In the paper, we analyse the impact of those threats on the train GNSS-based position estimation performance. At this aim, several scenarios have been generated by using both real data acquired on a railway test-bed in Sardinia, and synthetic data generated in the lab through ad hoc multipath and foliage models. A sensitivity analysis has been conducted, varying main scenarios parameters (e.g. height of obstacles, presence of trees and shadowing). The result of the performed analysis, in terms of availability, accuracy and integrity, are here presented. mitigations implemented by the ERTMS at system level are not considered since the attention is focused on GNSS only

Effect of increased pCO2 on the planktonic metabolic balance during a mesocosm experiment in an Arctic fjord

The effect of ocean acidification on the balance between gross community production (GCP) and community respiration (CR) (i.e., net community production, NCP) of plankton communities was investigated in summer 2010 in Kongsfjorden, west of Svalbard. Surface water, which was characterized by low concentrations of dissolved inorganic nutrients and chlorophyll a (a proxy of phytoplankton biomass), was enclosed in nine mesocosms and subjected to eight pCO2 levels (two replicated controls and seven enhanced pCO2 treatments) for one month. Nutrients were added to all mesocosms on day 13 of the experiment, and thereafter increase of chlorophyll a was provoked in all mesocosms. No clear trend in response to increasing pCO2 was found in the daily values of NCP, CR, and GCP. For further analysis, these parameters were cumulated for the following three periods: phase 1 – end of CO2 manipulation until nutrient addition (t4 to t13); phase 2 – nutrient addition until the second chlorophyll a minimum (t14 to t21); phase 3 – the second chlorophyll a minimum until the end of this study (t22 to t28). A significant response was detected as a decrease of NCP with increasing pCO2 during phase 3. CR was relatively stable throughout the experiment in all mesocosms. As a result, the cumulative GCP significantly decreased with increasing pCO2 during phase 3. After the nutrient addition, the ratios of cumulative NCP to cumulative consumption of NO3 and PO4 showed a significant decrease during phase 3 with increasing pCO2. The results suggest that elevated pCO2 influenced cumulative NCP and stoichiometric C and nutrient coupling of the plankton community in a high-latitude fjord only for a limited period. However provided that there were some differences or weak correlations between NCP data based on different methods in the same experiment, this conclusion should be taken with caution

Effects of ocean acidification on invertebrate settlement at volcanic CO<inf>2</inf> vents

We present the first study of the effects of ocean acidification on settlement of benthic invertebrates and microfauna. Artificial collectors were placed for 1 month along pH gradients at CO2 vents off Ischia (Tyrrhenian Sea, Italy). Seventy-nine taxa were identified from six main taxonomic groups (foraminiferans, nematodes, polychaetes, molluscs, crustaceans and chaetognaths). Calcareous foraminiferans, serpulid polychaetes, gastropods and bivalves showed highly significant reductions in recruitment to the collectors as pCO2 rose from normal (336-341 ppm, pH 8.09-8.15) to high levels (886-5,148 ppm) causing acidified conditions near the vents (pH 7.08-7.79). Only the syllid polychaete Syllis prolifera had higher abundances at the most acidified station, although a wide range of polychaetes and small crustaceans was able to settle and survive under these conditions. A few taxa (Amphiglena mediterranea, Leptochelia dubia, Caprella acanthifera) were particularly abundant at stations acidified by intermediate amounts of CO2 (pH 7. 41-7.99). These results show that increased levels of CO2 can profoundly affect the settlement of a wide range of benthic organisms. © 2010 Springer-Verlag

Seagrass can mitigate negative ocean acidification effects on calcifying algae

The ultimate effect that ocean acidification (OA) and warming will have on the physiology of calcifying algae is still largely uncertain. Responses depend on the complex interactions between seawater chemistry, global/local stressors and species-specific physiologies. There is a significant gap regarding the effect that metabolic interactions between coexisting species may have on local seawater chemistry and the concurrent effect of OA. Here, we manipulated CO2 and temperature to evaluate the physiological responses of two common photoautotrophs from shallow tropical marine coastal ecosystems in Brazil: the calcifying alga Halimeda cuneata, and the seagrass Halodule wrightii. We tested whether or not seagrass presence can influence the calcification rate of a widespread and abundant species of Halimeda under OA and warming. Our results demonstrate that under elevated CO2, the high photosynthetic rates of H. wrightii contribute to raise H. cuneata calcification more than two-fold and thus we suggest that H. cuneata populations coexisting with H. wrightii may have a higher resilience to OA conditions. This conclusion supports the more general hypothesis that, in coastal and shallow reef environments, the metabolic interactions between calcifying and non-calcifying organisms are instrumental in providing refuge against OA effects and increasing the resilience of the more OA-susceptible species.E.B. would like to thank the Coordenação de Aperfeiçoamento de Pessoas de Nível Superior (CAPES) for Masters funding. Funding for this project came from the Synergism grant (CNPq 407365/2013-3). We extend our thanks to the Brazil-based Projeto Coral Vivo and its sponsor PetroBras Ambiental for providing the Marine Mesocosm structure and experimental assistance.info:eu-repo/semantics/publishedVersio