Extraction of acceptor concentration map from EBIC experiments.

Controlling two dimensional doping distributions is an important benefit in order to check processed substrates or specific devices. To achieve this purpose, a new methodology is proposed in order to obtain qualitative maps of acceptor concentration from one EBIC image. Analytical models are used to help in defining the best experimental condition and to check the validity of the approach, and a TCAD simulation is performed on a realistic structure and shows promising results. Then, a measurement is carried out on a device and the epitaxy gradient is clearly visible, as well as the presence of Pwell layers.

In situ revascularization with rifampicin-soaked silver polyester graft for aortic infection: Results of a retrospective monocentric series of 18 cases.

OBJECTIVE: To evaluate the short and long-term results of in situ prosthetic graft treatment using rifampicin-soaked silver polyester graft in patients with aortic infection. MATERIAL AND METHOD: All the patients surgically managed in our center for an aortic infection were retrospectively analyzed. The primary endpoint was the intra-hospital mortality, secondary outcomes were limb salvage, persistent or recurrent infection, prosthetic graft patency, and long-term survival. RESULTS: From January 2004 to December 2015, 18 consecutive patients (12 men and 6 women) were operated on for aortic infection. Six mycotic aneurysms and 12 prosthetic infections, including 8 para-entero-prosthetic fistulas, were treated. In 5 cases, surgery was performed in emergency. During the early postoperative period, we performed one major amputation and two aortic infections were persistent. Intra-hospital mortality was 27.7%. The median follow-up among the 13 surviving patients was 26 months. During follow-up, none of the 13 patients presented reinfection or bypass thrombosis. CONCLUSION: This series shows that in situ revascularization with rifampicin-soaked silver polyester graft for aortic infection have results in agreement with the literature in terms of intra-hospital mortality with a low reinfection rate.

From EBIC images to qualitative minority carrier diffusion length maps.

A novel method is presented with the aim to perform minority carrier diffusion length map on cross-sectional samples. The method is based on one Electron-Beam Induced Current (EBIC) acquisition and on the analyze of the EBIC signal slope variation on each scanned points. This method is applied on a pinned photodiode array realized on a low doped silicon epitaxy, and the electron diffusion length map which is extracted is in good accordance with our expectation taking into account the doping distribution of the device. A TCAD simulation also confirms quantitatively the measured diffusion length map. Advantages and drawbacks of this method are discussed in this study.

Evaluation of overpressure prediction models for air blast above the triple point.

The increase of blast exposures leads to the need for better assessment of the blast threat. Empirical models describing the blast propagation in ideal conditions as free-field or surface detonations are commonly employed, but in some configurations the ground-reflected shock should be treated explicitly. Empirical models permit the prediction of the blast characteristics with the ground-reflected shock. The present study uses some original experimental data to evaluate the accuracy of the predicted overpressure with time regarding the reflected shock characteristics. Three methods are tested. The first method, called method of images (MOI) and linearly adding a virtual ground-symmetrical source blast to the free-field blast, is quick but lacks accuracy regarding the reflected shock characteristics. The second method, based on the LOAD_BLAST_ENHANCED function of the commercial LS-DYNA framework, better captures the reflected shock compared to the MOI, but the overall differences with experimental data are of the same order of magnitude as for the MOI. An original fit is introduced, based on standard physical parameters. The accuracy of this fit on the reflected shock characteristics, and the better match with the overall overpressure time series, shows its potential as a new empirical blast predicting tool.

Shape plasticity in response to water velocity in the freshwater blenny Salaria fluviatilis.

A non-random association between an environmental factor and a given trait could be explained by directional selection (genetic determinism) and by phenotypic plasticity (environmental determinism). A previous study showed a significant relationship between morphology and water velocity in Salaria fluviatilis that conformed to functional expectations. The objective of this study was to test whether this relationship could be explained by phenotypic plasticity. Salaria fluviatilis from a Corsican stream were placed in four experimental channels with different water velocities (0, 10, 20 and 30 cm s(-1)) to test whether there was a morphological response associated with this environmental factor. After 28 days, fish shape changed in response to water velocity without any significant growth. Fish in higher water velocities exhibited a more slender body shape and longer anal and caudal fins. These results indicate a high degree of morphological plasticity in riverine populations of S. fluviatilis and suggest that the previous relationship between morphology and water velocity observed in the field may largely be due to an environmental determinism.

Morphological variation in the freshwater blenny Salaria fluviatilis from Corsican rivers: adaptive divergence, phenotypic plasticity or both?

The first goal of this study was to determine whether morphological variation in the freshwater blenny Salaria fluviatilis results in spatially structured populations distributed around Corsica, France, which would suggest genetically differentiated populations through reproductive isolation by distance. The second goal was to determine whether some morphological traits are related to water velocity, one of the most contrasting habitat characteristics in these rivers, which would suggest an adaptation to local conditions. The results showed that the morphology of S. fluviatilis differed among the three main geographic areas studied in Corsica and that geographically distant populations of S. fluviatilis were less similar morphologically and genetically than close ones. The results also indicated that the morphological differences among populations conformed to functional expectations. Overall, the results suggest that the morphological variation of S. fluviatilis from Corsican rivers is an adaptive response to water velocity and that these populations are in a process of reproductive isolation by distance.

Vulnerability of CMOS image sensors in Megajoule Class Laser harsh environment.

CMOS image sensors (CIS) are promising candidates as part of optical imagers for the plasma diagnostics devoted to the study of fusion by inertial confinement. However, the harsh radiative environment of Megajoule Class Lasers threatens the performances of these optical sensors. In this paper, the vulnerability of CIS to the transient and mixed pulsed radiation environment associated with such facilities is investigated during an experiment at the OMEGA facility at the Laboratory for Laser Energetics (LLE), Rochester, NY, USA. The transient and permanent effects of the 14 MeV neutron pulse on CIS are presented. The behavior of the tested CIS shows that active pixel sensors (APS) exhibit a better hardness to this harsh environment than a CCD. A first order extrapolation of the reported results to the higher level of radiation expected for Megajoule Class Laser facilities (Laser Megajoule in France or National Ignition Facility in the USA) shows that temporarily saturated pixels due to transient neutron-induced single event effects will be the major issue for the development of radiation-tolerant plasma diagnostic instruments whereas the permanent degradation of the CIS related to displacement damage or total ionizing dose effects could be reduced by applying well known mitigation techniques.

[Postexercise duplex ultrasound to diagnose external iliac endofibrosis]. / Endofibrose de l'artère iliaque externe diagnostiquée par écho-doppler post-effort.

Arterial endofibrosis is a disease of recent discovery which concerns high-performance athletes, predominantly competitive cyclists. The preferential location is the external iliac artery. The symptoms are diverse (pain, edema, paresthesia), always linked to an effort. The diagnosis may be delayed due to atypical symptoms in athletes. Complementary tests are measure of the systolic pressure index after exercise, duplex ultrasound, CT angiography, MR angiography and arteriography. We report a case of endofibrosis where late diagnosis was established with postexercise duplex ultrasound, while CT angiography and arteriography failed to reveal characteristic abnormalities.

Circulating lipoprotein-associated phospholipase A2 in high-grade carotid stenosis: a new biomarker for predicting unstable plaque.

OBJECTIVE: To test plasma levels of lipoprotein-associated phospholipase A2 (Lp-PLA2) in patients with high-grade carotid stenosis according to plaque histology. METHODS: This cross-sectional single-centre study included patients with ≥70% North American Symptomatic Carotid Endarterectomy Trial (NASCET) carotid stenosis, who were treated surgically. Serum Lp-PLA2 and high-sensitivity C-reactive protein (hs-CRP) were determined on the day of surgery. Histopathological analysis classified carotid plaque as stable or unstable, according to AHA classification. RESULTS: Of the 42 patients (mean age 70.4 ± 10.5 years; 67% men), neurological symptoms were present in 16 (38%). Unstable plaques were found in 23 (55%). Median plasma level of Lp-PLA2 was significantly higher in patients with unstable plaque compared to those with stable plaque (222.4 (174.9-437.5) interquartile range (IQR) 63.5 vs. 211.1 (174.9-270.6) IQR 37.2 ng ml(-1); p = 0.02). Moreover, median Lp-PLA2 level were higher in asymptomatic patients with unstable plaque (226.8 ng ml(-1) (174.9-437.5) IQR 76.8) vs. stable plaque (206.9 ng ml(-1) (174.9-270.6) IQR 33.7; p = 0.16). Logistic regression showed that only the neurological symptoms (OR = 30.9 (3.7-244.6); p < 0.001) and the plasma Lp-PLA2 level (OR = 1.7 (1.1-12.3); p = 0.03) were independently associated with unstable carotid plaque as defined by histology. CONCLUSIONS: This study showed that circulating Lp-PLA2 was increased in patients with high-grade carotid stenosis and unstable plaque. Lp-PLA2 may be a relevant biomarker to guide for invasive therapy in asymptomatic patients with carotid artery disease.

Multicentric retrospective study of endovascular treatment for restenosis after open carotid surgery.

OBJECTIVES: To analyse perioperative and midterm outcomes of carotid artery stenting (CAS) for symptomatic >50% and asymptomatic >70% restenosis after open carotid surgery (OCS). DESIGN: A multicentric retrospective study. METHODS: Outcome measures 30-day death, neurologic and anatomic (thrombosis, restenosis) events. Univariant and multivariant logistic regression analyses were performed to identify predictive factors for neurologic and anatomic events. RESULTS: A total of 249 patients with a mean age of 69 years (range, 45-88) were treated for asymptomatic (86%) or symptomatic (14%) restenosis. The 30-day combined operative mortality and stroke morbidity was 2.8% in asymptomatic patients and 2.9% in symptomatic patients. Events during follow-up (mean duration, 29 months) included stroke in four cases, TIA in two, stent thrombosis in four and restenosis in 21. Kaplan-Meier estimates of overall survival, neurologic-event-free survival, anatomic-event-free survival and reintervention-free survival were 95.4%, 94.7%, 96.7% and 99.5%, respectively, at 1 year and 80.3%, 93.8%, 85.1% and 96%, respectively, at 4 years. Multivariant analysis showed that statin use was correlated with a lower risk of anatomic events (odds ratio (OR) = 0.15 (95% confidence interval (CI) 0.03-0.68), p = 0.01) and that bypass was associated with a higher risk of anatomic events than endarterectomy (OR = 5.0 (95% CI 1.6-16.6), p = 0.009). CONCLUSION: CAS is a feasible therapeutic alternative to OCS for carotid restenosis with acceptable risks in the perioperative period. Restenosis rate may be higher in patients treated after bypass.

Behavioural responses of prey fishes to habitat complexity and predation risk induce bias in minnow trap catches.

The effects of predation risk and habitat complexity on the efficiency of minnow traps to catch northern redbelly dace Chrosomus eos in laboratory experiments were investigated. Trap efficiency significantly decreased in the presence of vegetation and predators. These results suggest that the various antipredator behaviours used by prey fishes can affect trap efficiency.

[Long-term patency of a popliteal venous aneurysm treated surgically]. / Perméabilité à long terme d'un anévrisme veineux poplité traité chirurgicalement.

Popliteal venous aneurysms are infrequent but should be screened for with venous ultrasound in patients with acute or chronic venous diseases because of the unpredictable high risk of thromboembolism and potential curability. Therapeutic alternatives are discussed: follow-up, anticoagulation, surgery with different techniques. To illustrate this, we report the case of a 51-year-old woman presenting pulmonary embolism and left popliteal venous aneurysm treated surgically. Anticoagulation was stopped 12 months after surgery and primary patency was maintained 40 months after surgery. In patients with thromboembolism disease, clinicians should search for popliteal venous aneurysms in order to prevent recurrent thrombosis and adapt follow-up and treatment.

Fenestrated endovascular grafting: the French multicentre experience.

PURPOSE: This study aims to evaluate the medium-term outcomes following aortic aneurysm repair using fenestrated endografts performed in 16 French academic centres. MATERIALS AND METHODS: A retrospective analysis of prospectively collected data was carried out. This study included all patients treated with fenestrated endografts in France between May 2004 and January 2009. Patients were judged to be at high risk for open surgical repair. Fenestrated endografts were designed using computed tomography (CT) reconstructions performed on three-dimensional (3D) workstations. All patients were evaluated with CT, duplex ultrasound and plain film radiograph at discharge, 6, 12, 18 and 24 months, and annually thereafter. RESULTS: A total of 134 patients (129 males) were treated over the study period. Median age and aneurysm size were 73 years (range 48-91 years) and 56 mm (range 45-91 mm), respectively. A total of 403 visceral vessels were perfused through a fabric fenestration, including 265 renal arteries. One early conversion to open surgery was required. Completion angiography and discharge CT scan showed that 398/403 (99%) and 389/394 (99%) respective target vessels were patent. The 30-day mortality rate was 2% (3/134). Pre-discharge imaging identified 16 (12%) endoleaks: three type I, 12 type II and one type III. After the procedure, transient or permanent dialysis was required in four (3%) and two (1%) patients, respectively. The median duration of follow-up was 15 months (range 2-53 months). No aneurysms ruptured or required open conversion during the follow-up period. Twelve of 131 patients (9%) died during follow-up (actuarial survival at 12 and 24 months: 93% and 86%, respectively). Median time from procedure to death was 15 months. None of these deaths were aneurysm related. Aneurysm sac size decreased by more than 5 mm in 52%, 65.6% and 75% of patients at 1, 2 and 3 years, respectively. Three (4%) patients had sac enlargement within the first year, associated with a persistent endoleak. During follow-up, four renal artery occlusions were detected. A total of 12 procedure-related re-interventions were performed in 12 patients during follow-up, including six to correct endoleaks, and five to correct threatened visceral vessels. CONCLUSIONS: The use of endovascular prostheses with graft material incorporating the visceral arteries is safe and effective in preventing rupture in the medium term. A predictable high mortality rate was depicted during follow-up in this high-risk cohort. Meticulous follow-up to assess sac behaviour and visceral ostia is critical to ensure optimal results.

Early carotid endarterectomy after intravenous thrombolysis for acute ischaemic stroke.

UNLABELLED: After intravenous thrombolysis (IVT) for acute ischaemic stroke (AIS), a severe cervical internal carotid artery (ICA) stenosis may remain and increase the risk of recurrent stroke. Carotid endarterectomy (CEA) has been shown to be effective in reducing the risk of stroke. However, it is not well known whether CEA can be performed safely after thrombolysis, and, if so, when. We report a prospective study of CEA for residual high-grade cervical ICA stenosis performed within 15 days after IVT for AIS. METHODS: All the patients had a brain magnetic resonance imaging (MRI) within 3h of the stroke onset. One day after IVT in neurovascular unit, computed tomography (CT) angiography was performed to assess the brain and the patency of cervical arteries. CEA was performed on neurologically stable patients after full cerebral artery re-canalisation. Blood pressure was controlled with particular caution before and after CEA. RESULTS: Between January 2005 and January 2008, we operated consecutively on 12 patients. Their median National Institutes of Health Stroke Scale (NIHSS) score was 12 (range: 5-21). Combined intracranial (ICA)-middle cerebral artery (MCA) occlusion was present in 58.3% of the patients. The median time between onset of symptoms until CEA was 8 days (range: 1-16 days). Stroke and death rate at 30 days was 8.3% (one nonfatal haemorrhagic stroke). At 90 days, nine patients had a Rankin score of 0-1, one had a score of 2 and two had a score of 3. CONCLUSION: In patients with residual cervical ICA stenosis after IVT, we achieved full patency of the occluded artery and good functional prognosis at 3 months in all cases. We advocate for an extremely close monitoring of the blood pressure in the pre-, peri- and post-operative course and a close collaboration between neurologist and surgeon to determine the best timing for CEA.

Effects of dynamic landscape elements on fish dispersal: the example of creek chub (Semotilus atromaculatus).

Barriers along a watercourse and interconnections between drainage systems are dynamic landscape elements that are expected to play major roles in the dispersal and genetic structure of fish species. The objective of this study was to assess the role of these elements using creek chub (Semotilus atromaculatus) in the Mastigouche Wildlife Reserve (Québec, Canada) as model. Numerous impassable waterfalls and interconnections among drainage systems were inferred with geographic information systems and confirmed de visu. The analysis of 32 populations using seven nuclear microsatellites revealed the presence of three genetically distinct groups. Some groups were found upstream of impassable barriers and in adjacent portions of distinct drainage systems. Admixture among groups was also detected in some populations. Constraining phylogenetic procedures as well as Mantel correlation tests confirmed that the genetic structure is more likely to result from interconnections between the drainage systems than from the permanent network. This study indicates that landscape elements such as interconnections are of major importance for circumventing impassable barriers and colonizing lakes that are otherwise inaccessible. Such an approach could be relevant for determining the origins of fish species (i.e. native vs. introduced) in the context of conservation.

[Endovascular aneurysm repair follow-up by unenhanced and contrast-enhanced duplex ultrasound]. / Surveillance des endoprothèses aortiques abdominales : intérêt de l'échographie-doppler standard et avec contraste.

OBJECTIVE: Long-term surveillance is needed after endovascular aneurysm repair to monitor the aneurysm and search for persistent endoleaks. Our aim was to compare follow-up with duplex ultrasound, with and without a new contrast agent to track endoleaks, versus computed tomography angiography taken as the gold standard. MATERIAL AND METHOD: Patients treated with endograft were included prospectively from December 2005 to July 2006. Aortic duplex ultrasound and computed tomography were used to measure maximal aneurysm diameter and detect endoleaks. Patients with a high risk of endoleaks had a contrast-enhanced ultrasound with Sonovue (Bracco, Milan, Italy). We compared echographic and tomographic diameter and studied the sensitivity of ultrasound endoleak diagnosis. RESULTS: Sixty-seven patients were included. There was a good correlation between maximum anteroposterior diameters (CCI=0.98) measured by ultrasound and tomography, as well as mean maximum cross section diameters (CCI=0.96). Compared to tomography, the sensitivity of ultrasound endoleaks diagnosis was 44% (kappa=0.58). Contrast injection improved this sensitivity significantly (p<0.001) (sensitivity=88%; kappa=0.72). CONCLUSION: These findings confirmed the performance of our ultrasound method for endograft surveillance. Contrast-enhanced ultrasound significantly improves the sensitivity of detection of endoleaks. We suggest alternating ultrasound and tomographic exams. A unique report chart for use nationwide would be useful for standardizing follow-up.

The haemodynamics of the distal arterial Y-shaped autograft bypass-flap in a porcine experimental model.

BACKGROUND: The haemodynamic effects of revascularisation with combined bypass and free-muscle flap remain controversial. In a porcine experimental model, we investigated the transplantation-induced changes in the haemodynamics of a Y-shaped combined arterial autograft bypass-muscle flap (AABF). METHODS: Anatomy of AABF was identified in eight dissections in four porcine cadavers. In five animals, AABF served as a superficial femoral artery (SFA) defect replacement. Modelled, triggered pulsatile pressure (P) and flow (Q) waves delivered mean haemodynamics and PQ hysteresis loops before and after transplantation at days 0 and 10. RESULTS: Anatomically, AABF combined subscapular and circumflex-scapular arteries, and thoracodorsal artery as latissimus dorsi flap pedicle. Surgical feasibility and AABF patency were confirmed in each case. At day 0, the proximal flow was increased in the grafted Y-shaped AABF, which also adopted the specific SFA pulsatile haemodynamics. Regulatory mechanisms of AABF vasomotricity were preserved and AABF-flow-dependence amplified the flow in the distal segment, which otherwise preserved its own flow dependence. At 10 days, the AABF flow was unchanged in the distal segment, and remained elevated in the proximal and pedicle segments. CONCLUSIONS: Combined AABF, as a single one-piece arterial autograft, was shown highly adaptive to the receiving arteries. The transplantation-induced changes in AABF pulsatile flow profile and vascular reactivity improve the overall graft flow, and strongly advocate for beneficial effects on the blood propelling capacity of the grafted circulation.

Does predation risk influence habitat use by northern redbelly dace Phoxinus eos at different spatial scales?

This study investigated the relationship between spatial variations in predation risk and abundance of northern redbelly dace Phoxinus eos at both macroscale (littoral v. pelagic zones) and microscale (structured v. open water habitats in the littoral zone) of Canadian Shield lakes. Minnow traps were placed in both structured and open water habitats in the littoral zone of 13 Canadian Shield lakes, and estimates of the relative predation risk of P. eos in both the pelagic and the littoral zones were obtained from tethering experiments. Results showed that (1) the mean abundance of P. eos in the littoral zone was positively correlated with the relative predation risk in the pelagic zone, (2) P. eos preferentially used structured over open water habitats in the littoral zone and (3) this preference was not related to the relative predation risk in the littoral zone but decreased as the relative predation risk increased in the pelagic zone. At the lake level, these results support the hypothesis that P. eos enter the littoral zone to avoid pelagic piscivores. At the littoral zone level, the results do not necessarily contradict the widely accepted view that P. eos preferentially use structured over open habitats to reduce their predation risk, but suggest that flexibility in antipredator tactics (e.g. shelter use v. shoaling) could explain the spatial distribution of P. eos between structured and open water habitats.