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We describe the case of a patient who had been on hemodialysis for 8 years using a native arteriovenous fistula cannulated through the Venous Window Needle Guide™ device (VWING). The overall outcome was excellent and complication-free with intact state of the underlying vessel and a high degree of patient satisfaction. The patient was able to carry out self-cannulation without any difficulty almost from the very beginning. The current unavailability of VWING is a missed opportunity in the field of vascular access.

Central venous cannulation is a frequent need for urgent or scheduled hemodialysis. Many studies confirmed the pivotal role of ultrasound in this procedure. Vascular access guidelines strongly recommend ultrasound guidance. Its usefulness has been demonstrated not only in reducing complications of venipuncture but more recently for the evaluation of central venous catheter (CVC) placement and real-time check for possible complications. The use of ultrasound requires a precise technique for the correct handling of the probe and the needle movement. Different approaches as the out-of-plane, in-plane, and oblique methods are available, enabling the most appropriate for the individual case. Although the learning curve for CVC ultrasound placement is usually fast, formal training and certification for beginners are strongly recommended.

Background We report the use of a 4 mm vascular Amplatzer for the occlusion of a renal arterovenous fistula between the renal artery, at the hylum trifurcation point, and an aneurismatic vein draining into the main renal vein, where there was no possibility to use any other device from the venous side, because of the diameter and the high flow, neither from the arterious side without sacrificing lobar branches. The device was implanted at the exact point of communication, like a patent foramen ovale occluder, with the distal disc into the artery lumen and the other two proximal discs into the venous side. Case presentation A 34-years-old Caucasian woman suffered several episodes of paroxysmal supraventricular tachycardia associated with dyspnoea, after the onset of post-pregnancy hypertension. She underwent CTA, spectral Doppler sonography and angiography which showed a renal arteriovenous fistula (RAVF) between the renal artery, at the hylum trifurcation point, and an extremely ectatic vein draining into the main renal vein of the right kidney. With both arterial and venous access, the RAVF was selectively embolized using a 4 × 6 mm Amplatzer Vascular Plug II, released into the communication between artery and vein ensuring the patency of vessels involved. The RAVF was almost completely excluded and the hemodynamic effects associated were also corrected. Conclusions The use of this device, though in an alternative way, allowed the exclusion of the high flow A-V fistula without sacrificing any parent renal vessel and preserving the renal function.

Pulmonary embolism is the third most common cause of cardiovascular emergency. Risk stratification is crucial in the clinical and therapeutic management of these patients. The latest European guidelines introduced a new classification based on short-term mortality risk stratification, dividing patients into four categories (high, intermediate-high, intermediate-low and low risk). Despite the limited evidence in this field, the percutaneous treatment of pulmonary embolism represents an option of interest; however, correct patient selection and device choice should be better investigated. In this article, we present two case reports of patients with intermediate-high-risk and high-risk pulmonary embolism treated with the EkoSonic Endovascular System (EKOS Corp., Bothell, WA, USA) and the FlowTriever System (Inari Medical, Irvine, CA, USA), respectively.

Background and purpose We sought to investigate whether there are gender differences in clinical outcome after stroke due to large vessel occlusion (LVO) after mechanical thrombectomy (EVT) in a large population of real-world patients. Methods From the Italian Registry of Endovascular Thrombectomy, we extracted clinical and outcome data of patients treated for stroke due to large vessel occlusion. We compared clinical and safety outcomes in men and women who underwent EVT alone or in combination with intravenous thrombolysis (IVT) in the total population and in a Propensity Score matched set. Results Among 3422 patients included in the study, 1801 (52.6%) were women. Despite older age at onset (mean 72.4 vs 68.7; p Conclusions Subject to the limitations of a non-randomized comparison, women with stroke due to LVO treated with mechanical thrombectomy had a better chance to achieve complete recanalization, and 3-month functional independence than men. The results could be driven by women who underwent combined treatment.

This work elucidates friction in Poly-Ether-Ether-Ketone (PEEK) sliding contacts through multiscale simulations. At the nanoscale, non-reactive classical molecular dynamics (MD) simulations of dry and water-lubricated amorphous PEEK–PEEK interfaces are performed. During a short running-in phase, we observe structural transformations at the sliding interface that result in flattening of the initial nanotopographies accompanied by strong polymer chain alignment in the shearing direction. The MD simulations also reveal a linear pressure – shear stress dependence and large adhesive friction in dry conditions. This dependence, summarized in a nanoscale friction law, is of central importance for our multiscale approach, since it forms a link between MD and elastoplastic contact mechanics calculations. An integration of the nanoscale friction law over the real area of contact yields a macroscopic friction coefficient that allows for a meaningful comparison with measurements from macroscopic tribometer experiments. Severe normal loading conditions result in significant wear and high experimental friction coefficients µ≈0.5–0.7, which are in good agreement with the calculated values from the multiscale approach in dry conditions. For milder experimental loads, our multiscale model suggests that lower friction states with µ≈0.2 originate in the presence of physisorbed molecules (e.g., water), which significantly reduce interfacial adhesion.

This work elucidates friction in Poly-Ether-Ether-Ketone (PEEK) sliding contacts through multiscale simulations. At the nanoscale, non-reactive classical molecular dynamics (MD) simulations of dry and water-lubricated amorphous PEEK-PEEK interfaces are performed. During a short running-in phase, we observe structural transformations at the sliding interface that result in flattening of the initial nanotopographies accompanied by strong polymer chain alignment in the shearing direction. Our MD simulations reveal a linear pressure-dependence of the shear stress τMD (P,σH2o) [MPa]=0.18P + 50.5 - 1.25σH2o, where σH2o [nm-2] is the surface number density of adsorbed water molecules. This constitutive law is of central importance for our multiscale approach, since it forms a link between MD and elastoplastic contact mechanics calculations. An integration of τMD (P,σH2o) over the real area of contact yields a macroscopic friction coefficient μmacro (σH2o) that allows for a meaningful comparison with friction coefficients μexp≈0.5-0.7 which are in good agreement with the calculated dry friction coefficients μmacro(σH2o=0).For milder experimental loads, our multiscale model suggests that the lower friction states with μexp≈0.2 originate in the presence of physisorbed molecules (e.g. water), which significantly reduce interfacial adhesion.

In this work we assess the applicability of the adjoint optimization technique for determining optimal surface topographies of two surfaces in relative motion in presence of a thin lubricant films that can cavitate. Among the existing numerical tools for topology optimization in engineering problems, the adjoint method represents a promising and versatile technique, which can also be applied to the field of full film tribology. In particular, the design of surfaces with complex textures can thoroughly benefit from this method, as it allows dealing with a large number of degrees of freedom at low computational cost. We show that this optimization method can be successfully applied to cavitating lubricant flows such as in pin-on-disc tribometers, giving the possibility to extend the results also to other typical applications such as journal and slider bearings. It is shown that the adjoint method can optimize the whole gap height distribution point by point in a more efficient way than traditional optimization approaches and parametric studies. In particular, thanks to the sensitivity analysis the adjoint method is able to find the placement and depth profile of each texture element.

This work discusses the use of slipping domains to improve load support in water-lubricated microsystems through a multi-scale approach. A semi-analytical continuum formulation is developed to calculate changes in pressure distribution for a line contact with added slip. It is found that the slipping region maximizing hydrodynamic lift should favor inlet flow, but not be located at the contact outlet. Estimations for its positioning are provided. Slip on flat surfaces gives the largest gains in load support and friction reduction, but moderate improvements are also possible on circular geometries featuring high convergence ratios. Finally, Molecular Dynamics simulations are employed to quantify slip on hydrophobic surfaces. Among the considered topologies, graphene is an excellent candidate to generate slip in water-lubricated microsystems.

The shearing of compressible fluids in a channel with parallel walls is studied to understand the impact of viscous dissipation and thermodynamics in thin lubricant films. Numerical simulations based on the compressible Navier-Stokes equations and Reynolds equation, both coupled with the energy equation, are performed for a lubricant oil. Particular attention is paid to the resulting pressure losses in the plane channel. It is shown that viscous effects, that alter the classical Couette velocity profile towards a Couette-Poiseuille one, scale with the parameter ξ = μ 0 Ul / ( h 2 P ref ) , and that the pressure losses are proportional to the square of ξ.

In this work we assess the applicability of the adjoint optimization technique for determining optimal surface topographies of two surfaces in relative motion in presence of a thin lubricant films that can cavitate. Among the existing numerical tools for topology optimization in engineering problems, the adjoint method represents a promising and versatile technique, which can also be applied to the field of full film tribology. In particular, the design of surfaces with complex textures can thoroughly benefit from this method, as it allows dealing with a large number of degrees of freedom at low computational cost. We show that this optimization method can be successfully applied to cavitating lubricant flows such as in pin-on-disc tribometers, giving the possibility to extend the results also to other typical applications such as journal and slider bearings. It is shown that the adjoint method can optimize the whole gap height distribution point by point in a more efficient way than traditional optimization approaches and parametric studies. In particular, thanks to the sensitivity analysis the adjoint method is able to find the placement and depth profile of each texture element.

Reports of stuck hemodialysis catheters have been on the rise in recent years. Aim of this work is to report how this complication has been managed and the relative outcomes in a multicente Italian survey.Since 2012, the Italian Society of Nephrology (SIN) Project Group of Vascular Access has collected data among nephrologists on this complication. Data regarding 72 cases of stuck tunnelled central venous catheter (tCVC) in 72 patients were retrieved thanks to this survey.In 11 patients (15%) the stuck catheter was directly buried or left in place. Sixty-one cases were managed through advanced removal techniques. Among these, 47 (77%) stuck tunnelled central venous catheters were successfully removed, while 14 (23%) failed to be withdrawn. Considering removed tCVCs, the use of endoluminal balloon dilatation alone or in combination with other tools showed a percentage of success of 88%. The removal procedure involved numerous specialists. Some complications occurred, such as breakage of the line or bleeding, and two cases of haemopericardium during an advanced procedure.The survey shows how the stuck catheter complication was managed in different ways, with conflicting results. When utilized, endoluminal balloon dilatation proved to be the most effective and most often utilized technique, while some cases had suboptimal management or failure. This underlines how delicate the procedure is, and the need for both precise knowledge of this complication and timely organization of removal attempts.

Viscosities $\eta$ and diffusion coefficients $D_s$ of linear and branched alkanes at high pressures $P$$, Comment: 5 pages, 4 figures, supplementary material available on demand

Purpose To assess the safety and clinical benefit of the Lutonix drug-coated balloon (DCB) catheter for the treatment of dysfunctional arteriovenous fistulae (AVF) and grafts (AVG) in a heterogenous real-world population. Materials and Methods This multicenter, prospective study enrolled 320 subjects from 12 countries in 25 sites across Europe and Asia. A total of 392 lesions were treated with the Lutonix 035 DCB catheter. Lesions were de novo and restenotic, located in every part of the circuit from the cannulation zone to central venous outflow. In-stent restenotic lesions also were treated. The primary safety endpoint was freedom from serious adverse events involving the access circuit through 30 days. The primary effectiveness endpoint was target lesion primary patency (TLPP) through 6 months. Secondary endpoints included access circuit primary patency (ACPP) at 6 months and the investigation of factors that would independently influence the primary endpoints. Results The primary safety endpoint was 95.5%, while TLPP was 73.9% at 6 months, per Kaplan-Meier survival analysis. ACPP was 71% at 6 months. TLPP for stenosis of AVFs was 78.1%. Subgroup analysis showed significantly improved TLPP when DCB was dilated for ≥120 seconds (P = .007). TLPP was significantly better when predilation occurred compared with cases where only DCB angioplasty was performed (77% vs 48.6%, P = .0005). Conclusions The Lutonix AV Global Registry confirms that the Lutonix DCB is a safe and effective treatment option in real-world patients with dysfunctional AVF or AVG. Procedural details had a significant role in TLPP. No significant difference in TLPP was observed among different treatment areas.

Background The oral administration of the gum resin extracts of Indian frankincense (Boswellia serrata Roxb. ex Colebr) results in very low plasma concentrations of boswellic acids (BAs), being far below the pharmacologically active concentrations required in vitro for anti-inflammatory activity. For that reason the use of Indian frankincense in clinical practice and pharmaceutical development has substantially lagged behind. Recently the application of new formulation technologies resulted in a formulation of frankincense extract with lecithin, which revealed improved absorption and tissue penetration of BAs in a rodent study, leading for the first time to plasma concentrations of BAs in the range of their anti-inflammatory activity. Purpose In order to verify these encouraging results in humans, the absorption of a standardized Boswellia serrata extract (BE) and its lecithin formulation (CSP) was comparatively investigated in healthy volunteers. Study design According to a randomized cross-over design with two treatments, two sequences and two periods, 12 volunteers alternatively received the lecithin-formulated Boswellia extract (CSP) or the non-formulated Boswellia extract (BE) at a dosage of 2 × 250 mg capsules. Methods The plasma concentrations of the six major BAs (KBA, AKBA, βBA, αBA, AβBA, AαBA) were determined using LC/MS. Results With the exception of KBA, a significantly higher (both in terms of weight-to-weight and molar comparison) and quicker absorption of BAs from the lecithin formulation was observed, leading to Cmax in the range required for the interaction with their molecular targets. Conclusion These findings pave the way to further studies evaluating the clinical potential of BAs, and verify the beneficial effect of lecithin formulation to improve the absorption of poorly soluble phytochemicals.

The Venous Window Needle Guide (VWING™) has recently been proposed for patients with difficult arteriovenous fistula (AVF) access for hemodialysis due to deep vessels or other cannulation-related problems. This totally subcutaneous titanium device is sutured onto the upper wall of the matured fistula and may facilitate cannulation by the button-hole technique. We describe our initial experience with nine implants in six patients with a cumulative follow-up of 83 months, and make some experience-based technical suggestions for implant and surveillance radiological imaging. The indication for implantation was deep vessel, previous failure of cannulation or unsuitable site for direct cannulation. No infectious complications were observed during follow-up and proper blood flow was constantly achieved. Some difficulties were occasionally encountered with regard to cannulation; nonetheless, patient satisfaction was not significantly affected. VWING seems to be an interesting option in some patients provided that surgical implantation is carefully carried out and preventive measures against infections are strictly observed.

// Roberto Bini 1 , Simone Comelli 2 , Renzo Leli 1 , Giacomo Paolo Vaudano 2 , Daniele Savio 2 , Tiziana Viora 1 , Alfredo Addeo 3 1 General Surgery Department, SG Bosco Hospital, Turin, Italy 2 Interventional Radiology- Neuroradiology Department, SG Bosco Hospital, Turin, Italy 3 Oncology Department, Bristol Cancer Center, Bristol, UK Correspondence to: Roberto Bini, email: rebinidoc@gmail.com Keywords: debiri, rectal cancer, chemoembolization, cancer recurrence Received: November 09, 2015 Accepted: May 20, 2016 Published: June 10, 2016 ABSTRACT Purpose: Assess the feasibility, safety and efficacy of TACE with irinotecan loaded micro particles (debiri) for the treatment of locally advanced rectal cancer patients. Results: We assessed the Edmonton Symptom Assessment System (ESAS). The tool is designed to assess nine common symptoms in cancer patients: pain, tiredness, nausea, depression, anxiety, drowsiness, appetite, wellbeing and shortness of breath. The ESAS score was 7 in 10/12 (83%) patients before treatment and 6 in 2/12 (16.5%) patients. After treatment in 6/12 (50%) patients the score dropped to 3; 3/12 (33%) reported 4, 1/12 (8%) reported 2. All patients experienced local control disease with a degree of citoreduction; in 4 cases (33%) we observed outstanding responses with a dramatic reduction in the tumors size which led us to surgical radical resections. Materials and methods: We run a prospective mono-institutional study where we recruited, 12 non- consecutive patients with histology confirmation of rectal cancer, inoperable and not treatable due to severe comorbidities, or pelvic recurrence/progression after curative treatment, chemotherapy, radiotherapy and/or surgery. Their performance status (PS) ECOG was 2-3 . Twelve patients (10 male and 2 female) with a median age 71 (range 56-89) were recruited in the study. Conclusions: The study has met the primary endpoint and showed encouraging activity. Debiri could be a possible option for locally advanced/inoperable or recurred rectal cancer patients. Further trials are warranted to validate this methodic in early stages.

We generate representative structural models of amorphous carbon (a-C) from constant-volume quenching from the liquid with subsequent relaxation of internal stresses in molecular dynamics simulations using empirical and machine-learning interatomic potentials. By varying volume and quench rate we generate structures with a range of density and amorphous morphologies. We find that all a-C samples show a universal relationship between hybridization, bulk modulus and density despite having distinct cohesive energies. Differences in cohesive energy are traced back to slight changes in the distribution of bond-angles that will likely affect thermal stability of these structures., Comment: 26 pages, 7 figures

Background Acute lower limb ischemia (ALLI) poses a major threat to limb survival. For many years, surgical thromboembolectomy was the mainstay of treatment. Recent years have brought an endovascular revolution to the management of ALLI. It seems that the newly designed endovascular thrombectomy devices may shift treatment recommendations toward endovascular options. This protocol study aims to collect evidence supporting the latest hypothesis. Objective The devices under investigation are the Penumbra/Indigo Systems (Penumbra Inc). The objective of this clinical investigation is to evaluate, in a controlled setting, the early safety and effectiveness of the devices and to define the optimal technique for the use of these systems in patients with confirmed peripheral acute occlusions. Methods This study will be an interventional prospective trial of patients with a diagnosis of ALLI treated with Penumbra/Indigo devices. This project is intended to be a national platform where every physician invited to participate could register his or her own data procedure. The primary outcome is the technical success of thromboaspiration with the Indigo System. Assessment of vessel patency will be recorded using the Thrombolysis in Myocardial Infarction (TIMI) score classifications before and after use of the device. Clinical success at follow-up is defined as an improvement of Rutherford classification at 1-month follow-up of one class or more as compared to the preprocedure Rutherford classification. Secondary endpoints include the following: (1) safety rate at discharge, defined as the absence of any serious adverse events; (2) primary patency at 1 month, defined as a target lesion without a hemodynamically significant stenosis or reocclusion on duplex ultrasound (>50%) and without target lesion reintervention within 1 month; and (3) limb salvage at 1 month. Results The study is currently in the recruitment phase and the final patient is expected to be treated by the end of March 2019. A total of 150 patients will be recruited. Analyses will focus on primary and secondary endpoints. Conclusions These new endovascular thrombectomy devices that are specifically designed for peripheral intervention in this difficult set of patients, as those under investigation in the proposed registry, may offer improved clinical outcomes with lower rates of major systemic and local complications. Following completion of this study, it is expected that the value of the Indigo Thrombectomy System in the treatment of ALLI will be better defined. As a result, a shift of treatment recommendations toward endovascular options may be observed in the near future. International Registered Report Identifier (IRRID) DERR1-10.2196/9972

International audience; It is shown via molecular dynamics simulations that the occurrence of wall slip for linear alkanes confined between geometrically smooth surfaces depends on the wall-fluid interactions and the chain length of the lubricant molecules. A wall slip model based on the competition between these two factors is introduced. A surface parameter accounts for the wall-fluid interaction and commensurability, and is valid for both canonical and complex crystal lattices: this quantity is then linked to the shear stress transferred to the fluid molecules. The lubricant internal cohesion under confinement is described by a bulk viscosity term. Finally, a semi-analytical law for wall slip prediction including both the fluid viscosity and the surface characterization parameter is proposed.

Evaluate Magnetic Resonance (MR) and Magnetic Resonance Angiography (MRA) sensibility in the diagnosis and follow-up of dissection of Internal Carotid and Vertebral Artery (ICA/VA). We revalued MR examination of 36 patients, 24 men, 12 women, aged 18-69 years. All patients underwent brain TC and MR (GE 1 Tesla); in 16 subjects 3D Time-of-Flight (TOF-3D) MRA was performed and in 20 subjects a Contrast-Enhanced MRA (CEMRA) of neck and head arteries. Thirty-one patients underwent a MRA follow-up. Dissection involved ICA in 30 and VA in 8. MR showed ischemic signs in 25 cases, wall hematoma in 19, and was normal in 11. MRA showed 25 vessels stenosis, 12 occlusions, and 9 aneurysm. Follow-up MRA showed 6 cases of complete resolution of stenosis, 17 partial resolution, 2 aneurysmal dissecanting, 6 luminal alteration unchanged, 1 aneurysma enlarged. MRA represented a non-invasive technique as investigation in suspected cervicocephalic arteries dissection.

Patients with advanced and incurable colorectal cancer have a very poor prognosis. Curative-intent resection was performed in 70%–90% of cases in reported series of colorectal cancer, sometimes after neoadjuvant chemotherapy and radiotherapy. The remaining 10%-30% of patients are treated with palliative intent, where treatment is aimed at relieving disease-related symptoms and improving quality of life. The provision of palliative care for these patients is complicated and outcomes are often disappointing. Although there are many available options including a variety of surgical and nonsurgical interventions, the best management remains controversial. Transarterial chemoembolization with irinotecan-loaded drug-eluting beads (DEBIRI) is an effective, minimally invasive procedure performed by interventional radiologists that allows intra-arterial drug delivery to stop vascular feeding and exert local cytotoxic effects. We here report on a patient treated with DEBIRI followed by systemic chemotherapy with the FOLFOX regimen for locally advanced, inoperable colorectal cancer.

To evaluate the feasibility of percutaneous treatment of iliac aneurysms, a covered stent was inserted in nine men suffering from common iliac artery aneurysms (six cases), external iliac aneurysms (one case), or pseudoaneurysms (two cases). Placement of the stent was successful in all patients. In one patient, an endoprosthesis thrombosed after 15 days, but was successfully treated by thrombolysis and additional stent placement. At the follow-up examinations (mean period 22 months) all stent-grafts had remained patent. No late leakage or stenosis was observed.

Objective: We sought to evaluate the feasibility and results of intraoperative balloon angioplasty and additional stent placement of isolated stenosis of the brachiocephalic trunk. Patients and methods: Between May 1993 and October 1996, we treated eight patients with local stenosis of the innominate artery. Seven lesions were situated in the proximal and one in the middle third of the brachiocephalic trunk. Five patients were men and three were women, with ages ranging from 55 to 72 years (mean 59.5 years). All stenoses provoked severe blood flow reduction and caused clinical symptoms. Procedures were performed in an operating suite with fluoroscopic imaging capabilities. Through an anterolateral cervical approach the right common carotid artery was surgically exposed and then clamped to avoid atheroembolization during the subsequent procedure. Retrograde catheterization was performed to reach the stenosis of the brachiocephalic trunk. The lesion was dilated with a balloon catheter and successively stented. Follow-up examinations (color-coded duplex sonography, accompanied by clinical inspection and systolic blood pressure) were scheduled every 6 months. Results: In all patients the dilation of the stenosis of the innominate artery and the stent placement were successful without any side effects. No embolic events or other complications occurred. The postintervention angiography showed successfully dilated stenoses and patent stents in all cases. The technical success rate was 100%. Conclusions: On the basis of our preliminary data, we believe that, in selected patients, intraoperative balloon angioplasty of stenosis of the innominate artery with stent placement from the right common carotid artery approach is a safe and effective alternative to conventional operations. (J Thorac Cardiovasc Surg 1998;115:1316-20)

The term stuck catheter refers to the condition in which a catheter is not removable from a central vein using standard techniques. Although it is a rare complication, in the last few years it has been reported ever more frequently in hemodialysis due to the widespread use of tunneled catheters. Poor knowledge of the correct procedures and limited experience and training of the specialist in facing this problem are the main reasons for catheter internalization. Stuck catheter is often diagnosed by the nephrologist, who should be competent enough to manage this clinical complication. Among the many options for removing a stuck catheter from the fibrin sleeve, an interventional radiology approach, mainly with endoluminal balloon dilatation, probably provides the best solution. Vascular surgery should be reserved to selected cases in which percutaneous techniques have failed. Nephrologists must play a central role in organizing the treatment of this complication with other specialists in order to avoid making mistakes that may preclude future positive results.

The transition from ultra-thin lubrication to dry friction under high pressure and shear is studied using molecular dynamics: the quantity of lubricant in the confined film is progressively reduced toward solid-body contact. A quantized layer structure is observed for n-alkanes confined between smooth, wettable walls, featuring an alternation of well-layered, low friction configurations, and disordered ones, characterized by high friction, and heat generation. The molecular structure influences the ordering of the fluid and the resulting shear stress. In fact, Lennard-Jones fluids are characterized by low friction due to the absence of interlayer bridges, opposed to the always entangled states and high shear stresses for branched molecules. Surface geometry and wettability also affect the behavior of the confined lubricant. The presence of nanometer-scale roughness frustrates the ordering of the fluid molecules, leading to high friction states. Furthermore, local film breakdown can be observed when the asperities come into contact, with strong wall–wall interactions causing the maximum in shear stress. Finally, friction is limited to a small, constant value by the presence of smooth, non-wettable surfaces in the system due to the occurrence of wall slip.

International audience; Molecular dynamics simulations are used to analyze the local tribological behaviour of n-hexadecane confined between metal oxide surfaces under high pressure and shear rates. The number of lubricant molecules in the contact zone is then progressively reduced in order to achieve the direct contact between the atoms of the walls. Furthermore, the influence of the surface wettability and geometry (smooth versus nanorough surfaces) is studied. A particular focus is placed on the analysis of the structure and dynamics of the confined fluid. Results show that, in the case of smooth surfaces, two possible configurations can be reached. In some cases, a well defined structure is formed by the lubricant molecules, with an integer number of layers having equal density and low bridging. Between these ordered states, transition zones can be observed: the central layers merge together, and a disordered state is achieved in the center of the film. Finally, the ordering inside the fluid is always frustrated when nanometer scale roughness is present. Surface nature and geometry have a significant effect on the dynamics of the confined lubricant and friction. In the case of smooth wettable walls the lubricant is locked to the surfaces and shearing occurs between layers. Shear stress is then related to the degree of organization within the fluid: it oscillates from minima (in correspondence with ordered states), to maxima (at the transitions between well defined layers). On the other hand, wall slip at the fluid-surface interface occurs for smooth, non wettable surfaces: the shear stress is limited to a low, constant value. Nanorough surfaces cause a disordered state in the lubricant, and frustrate the occurrence of wall slip: hence, high friction ensues.

Keywords: aortic aneurism; atherosclerosis; endo-prothesis; daily haemodialysis; long-term RRTThe impressive calcifications seen in the computedtomography (CT) reconstruction of an aortic aneur-ysm of the abdominal aorta in Figure 1 belong to a 48-year-old male, on renal replacement therapy (RRT)from the age of 22. His end-stage renal diseasewas membrano-proliferative glomerulonephritis withsevere and prolonged nephrotic syndrome. In 1981,3 years after diagnosis, he started RRT on peritonealdialysis; he was switched to haemodialysis in 1985 dueto functional exhaustion of the peritoneum, and acadaveric graft was performed in 1993. Haemodialysiswas resumed in 1996 after graft failure due to recurrentmembranous and proliferative glomerulonephritis,again with severe nephrotic syndrome. He hadhypertension, usually well controlled by multipledrug therapy, parathyroidectomy because of severehyperparathyroidism unresponsive to conservativetreatment (1993) and a coronary by-pass (1997). Theaortic aneurysm shown in Figure 1 was first diagnosedin 1991: at that time, the maximum diameter was4.2cm. The diameter was stable until March 2000,when it increased to 4.6cm and further to 4.8cmin November 2000, despite a daily haemodialysisschedule (started in 1999), minimizing weight lossper dialysis and with a good blood pressure controlwithout need for drug therapy.Balancing the young age of the patient and thesurgical risks due to the diffuse arterial calcificationstypical of uraemic patients (Figure 2), a percutaneousendoluminal approach was chosen and successfullyperformed in January 2001, employing a modular

e20562 Background: We evaluated feasibility, safety and efficacy of IAIRIM on a compassionate use basisto treat locally UCRC and investigated a volume reduction of the target lesion. Methods: We considered patients with UCRC not eligible for any conventional treatment presenting severe anemia from rectal bleeding, colon obstruction and severe pain. A multidisciplinary evaluation was performed by surgeon, radiologist and oncologist. Patients underwent abdominal quadriphasic CT scan, in order to obtain a preliminary arterial mapping of the tumour; colostomy was performed in all patients. Angiography of superior and inferior mesenteric arteries was obtained to define the lesion vascularization and perform IAIRIM. A month later a new CT scan evaluation was performed to evaluate the volume of the target on Aw Volume share 2 (slice thickness 5mm). We defined the results adopting MASS, RECIST and mChoi response criteria. QoL was reported adopting Edmonton scale and EORTC QLQ-C30. Results: Ten patients were enrolled, IAIRIM was successfully performed in all without major complications. Ten patients experienced a clinical improvement with disappearance of bleeding and reduction of pain in a week. Fever lasting 36 hours (24-48) and minimal discomfort procedure related in were observed in all . Reduced but persisting muchorrea and tenesm were reported in 4 patient. After four months all patients were alive without pain or bleeding. 8/10 patients experienced mass reduction ( -39%; range -96% / +7%) and 2/10 no evidence of progression. QoL: Edmonton scale (considering only pain, fatigue, well-being and depression items) was around 7 in 8/10 patients before treatment and 6 in 2/10 patients. After treatment 6/10 patients reported mean score 3; 3/10 reported 4, 1/10 reported 2. Using EORTC QLQ-C30, mean score decreased from 3 to 2. Conclusions: IAIRIM seems feasible, with low side effects in patients bearing UCRC considered out of usual approaches. A reduction of symptomatic treatments and an increase of QoL (Edmonton and EORT QLQ-C30 scale) has been recorded in all patients. Volume reduction of the tumour has been observed in nine patients. Further experiences are warranted.