Localized Nanoresonator Mode in Plasmonic Microcavities.

Submicron-thick hexagonal boron nitride crystals embedded in noble metals form planar Fabry-Perot half-microcavities. Depositing Au nanoparticles on top of these microcavities forms previously unidentified angle- and polarization-sensitive nanoresonator modes that are tightly laterally confined by the nanoparticle. Comparing dark-field scattering with reflection spectroscopies shows plasmonic and Fabry-Perot-like enhancements magnify subtle interference contributions, which lead to unexpected redshifts in the dark-field spectra, explained by the presence of these new modes.

Rendering dark modes bright by using asymmetric split ring resonators.

We have studied both theoretically and experimentally symmetric and asymmetric planar metallic Split Ring Resonators. We demonstrate that introducing structural asymmetry makes it possible to excite several higher order modes of both even (l = 2) and odd (l = 3, 5) order, which are otherwise inaccessible for a normally incident plane wave in symmetric structures. Experimentally we observe that the even mode resonances of asymmetric resonators have a quality factor 5.8 times higher than the higher order odd resonances.

The role of chiral local field enhancements below the resolution limit of Second Harmonic Generation microscopy.

While it has been demonstrated that, above its resolution limit, Second Harmonic Generation (SHG) microscopy can map chiral local field enhancements, below that limit, structural defects were found to play a major role. Here we show that, even below the resolution limit, the contributions from chiral local field enhancements to the SHG signal can dominate over those by structural defects. We report highly homogeneous SHG micrographs of star-shaped gold nanostructures, where the SHG circular dichroism effect is clearly visible from virtually every single nanostructure. Most likely, size and geometry determine the dominant contributions to the SHG signal in nanostructured systems.

Hotspot decorations map plasmonic patterns with the resolution of scanning probe techniques.

In high definition mapping of the plasmonic patterns on the surfaces of nanostructures, the diffraction limit of light remains an important obstacle. Here we demonstrate that this diffraction limit can be completely circumvented. We show that upon illuminating nanostructures made of nickel and palladium, the resulting surface-plasmon pattern is imprinted on the structures themselves; the hotspots (regions of local field enhancement) are decorated with overgrowths, allowing for their subsequent imaging with scanning-probe techniques. The resulting resolution of plasmon pattern imaging is correspondingly improved.

Asymmetric optical second-harmonic generation from chiral G-shaped gold nanostructures.

We present a new electromagnetic phenomenon-the asymmetric second-harmonic generation from planar chiral structures. The effect consists in distinguishing the handedness of a chiral material by rotating the sample in an experiment involving solely linearly polarized light. This phenomenon originates in the surface plasmon resonance of chiral gold nanostructures, where homodyne interference of anisotropic and chiral electric and/or magnetic multipoles appears to play an important role.

Subject-Specific Effect of Metallic Body Accessories on Path Loss of Dynamic on-Body Propagation Channels.

This paper presents the investigation of path loss variation for subject-specific on-body radio propagation channels, considering the effect of metallic spectacles and loop like metallic accessories. Adding metallic items may affect the operability of Body Centric Wireless Communications (BCWC). Measurements were carried out in an RF-shielded room lined with microwave absorbing sheets for strategically placed bodyworn antennas covering the upper front torso and the lower limbs. The path loss of the on-body radio channel was characterized explicitly taking into account the body size of the subjects. For metallic loop-like accessories, the results indicate that for underweight subjects, there was a slightly higher influence, up to 2%, compared to normal and overweight subjects. Our findings indicate that a noticeable effect exists on on-body channels for dynamic movements where the metallic watch acts as a local scatterer that affects the non-line-of-sight (NLOS) signal path between transmitter and receiver for underweight subjects in comparison to normal and overweight subjects. The path loss decreases when the receiving terminal was positioned very close to the metallic item. If a loop-like metallic accessory is not appropriately considered when designing the radio channel on a subject, the reliability of the body-centric wireless system may degrade.

Comparison of iohexol and ioxaglate for intravenous digital subtraction angiography of the neck and head.

Two hundred patients undergoing intravenous digital subtraction angiography of the cerebral circulation were examined on a random basis with either iohexol 350 mg I/mL or ioxaglate 320 mg I/mL. The two low osmotic media provided equally satisfactory image quality and diagnostic possibilities. No significant differences were found in incidence and severity of adverse reactions.

Subclavian vein thrombosis: a frequent complication of subclavian vein cannulation for hemodialysis.

Subclavian vein cannulation was suggested as a temporary vascular access for hemodialysis since one of its advantages was considered to be no damage to blood vessels. As we observed six patients with symptomatic subclavian vein thrombosis among 148 patients having received subclavian vein cannulation for hemodialysis, we systematically performed subclavian venogram in 42 asymptomatic patients selected on the basis of a history of previous subclavian vein cannulation. Venograms were performed 15.7 +/- 8.9 months after the removal of the last catheter. Eight patients (19%) had complete thrombosis or severe stenosis of the subclavian vein while six patients (14%) had minimal luminal defects. Considering together the 48 patients, the group with thrombosis or severe stenosis (group 1, n = 14) was compared with the group with minimal defects or normal venograms (group 2, n = 34). In group 1, as compared with group 2, there were more female (64% vs 32%, p = 0.02), more cannulations per vein (1.87 +/- 0.35 vs 1.32 +/- 0.08, p less than 0.05) and more cumulative days of cannulation per vein (35.1 +/- 7.9 vs 24.4 +/- 1.1, p less than 0.001). No difference between the two groups was seen for the number of catheter infections, the number of catheters with poor flow or obstruction, the coagulation screening of the patients or the time-length between the removal of the last catheter and the venogram study. Two of the initially asymptomatic patients developed later on clinical problems related to the subclavian vein thrombosis. We conclude that the subclavian vein cannulation leads to significant damages of the vessels, excluding a whole arm, for future vascular access in some patients.

[Venous exploration of impotence of vascular origin]. / Exploration veineuse de l'impuissance d'origine vasculaire.

Vascular origin accounts for more than 25% of cases of disturbances of erection. Venous pathology may explain the majority of erectile dysfunctions in patients with normal arterial anatomy. We have performed cavernography in 115 patients with monitoring of intracavernous pressure. Nocturnal plethysmography was recorded in all cases to prove the organic etiology of the erectile dysfunction. Cavernography was realized after puncture of both corpora cavernosa by two microcatheters (19-21 G). The intracavernous pressure was recorded through 1 of them and the contrast medium infused through the other. The contrast medium is infused at a rate of 80-120 ml/min. until the penis appears erect. The simultaneous recording of the intracavernous pressure then showed a rapid increase of the pressure curve followed by a stabilization at greater than or equal to 90 mHg. The flow to maintain the erection reach 1/3 of the flow needed to induce the erection. The venous leak is characterized by the absence of erection, no increase in intracavernous pressure and a rapid opacification of the vein. Artificial erection induced in impotent men allows to classify patients with vascular organic impotence into three categories: those with pure arterial insufficiency, those with pure venous leak, and patients with both.

[In loco fibrinolytic treatment of acute ischemia of the lower limbs]. / Traitement fibrinolytique in loco des ischémies aiguës des membres inférieurs.

Peripheral artery occlusion produced by thrombosis or embolus can be cured by intra-arterial low dose thrombolysis without severe hemorrhagic complications. 18 patients suffering of acute ischemia of lower limbs were treated by intra-arterial streptokinase infusion. Diagnostic angiography is performed by antegrade femoral puncture using a 5F straight catheter. The tip of the catheter is placed within the thrombus. After a bolus of 10 000 U, streptokinase is infused at the rate of 2,000 U/min. Fibrinolysis is usually achieved within 70 min with a total dose of 150,000 U. Arterial recanalization occurred in 14 patients, in 6 cases underlying stenosis was successfully treated by percutaneous transluminal angioplasty. No severe complications were encountered.

[Transluminal percutaneous angioplasty by thermal lasers. 20 cases of peripheral artery occlusion]. / Angioplastie transluminale percutanée assistée au laser thermique. Expérience de 20 cas d'oblitérations artérielles périphériques.

The authors report their experience of laser thermal angioplasty in a series of 20 patients. An argon laser with a 1.5 or 2.0 millimeter diameter metalcapped optical fiber (Hot Tip Trimedyne Inc.) was used; the laser probe was pushed to the occlusion point; after a channel was produced through the obliteration, a conventional percutaneous balloon angioplasty was performed. The indications were: 4 primitive iliac occlusions, 15 femoral/popliteal occlusions and 1 subclavian obliteration. The immediate results were as follows (table I): 75% overall recanalization (50% at the iliac level, 87% at the femoral/popliteal level and failure at the subclavian level); 5 notable complications were observed (2 limb ischaemia, 2 voluminous inguinal haematoma and 1 aortic cross perforation) without clinical sequelae. The short term follow-up (1 to 8 months) of the successfully treated patients (table II) shows 100% permeability at the iliac level and 77% at the femoral/popliteal level. We conclude that laser thermal angioplasty is a very attractive method in the treatment of primitive iliac and femoral/popliteal occlusions. The well-defined indications must form the subject of a closely discussion between the angiologist, the vascular surgeon and the interventional radiologist.

[Evaluation of the permeability of aortocoronary bypass by digital angiography]. / Evaluation de perméabilité des pontages aorto-coronariens par angiographie numérisée.

Evaluation of coronary artery bypass graft patency by intra-arterial digital subtraction angiography was performed in 201 patients. A first group of 150 asymptomatic patients was systematically evaluated for post-operative screening 8.5 days after surgery as an immediate check on surgical results. Grafts were found occluded in 2.3%. A second group of 51 patients complaining of recurrent angina was studied 10 months (range 2 months to 9 years) after operation. Angiography revealed that 90% of grafts were patent but 8 grafts stenoses were diagnosed. In both groups, opacification of the run-off was achieved in 83%, but the quality of opacification was very low.

Dysplasia epiphysealis hemimelica (Trevor's disease).

The authors report a case of dysplasia epiphysealis hemimelica. This is a benign osteochondromatous epiphyseal overgrowth affecting most commonly the inferior limbs. The cartilage cap of the lesion can be demonstrated very accurately by MRI (gradient echo sequence). Early diagnosis and treatment is vital in preventing articular malformation and malfunction.

[Rt-PA thrombolysis in the treatment of massive pulmonary embolism]. / Thrombolyse met rt-PA voor de behandeling voor massale longembolie.

We present the case of a young comatose female patient in whom a massive pulmonary embolism was diagnosed by pulmonary angiography. During the angiography, not only successful thrombolytic therapy with recombinant human tissue-type plasminogen activator (rt-PA) (100 mg) was performed, but measuring of the pulmonary artery pressures, oxygen and carbon dioxide levels was also possible. Thrombolysis seems to be a good alternative to surgical thrombectomy.

[Percutaneous intentional extraluminal recanalization of the femoropopliteal artery. Initial experiences and results]. / Percutane intentionele extraluminele recanalisatie van de femoropopliteale arterie. Initiele ervaringen en resultaten.

Between July 1994 and April 1995, 14 patients with a chronic occlusion of the femoropopliteal artery were treated by percutaneous intentional extraluminal recanalisation (PIER). It concerned 11 males and 3 females with a mean age of 65 years (50-76 years). Twelve patients were smokers, two patients had diabetes mellitus. Ten patients had severe claudication, four patients suffered from rest pain, three of the latter had ulcerations. In all patients, recanalisation and balloon dilatation could be established. However, angiographic result was unsatisfactory in one case. There were no complications. Clinical follow-up varied from 2 weeks to 9 months. Two patients needed a surgical femoropopliteal bypass respectively 4 and 7 months after recanalisation because of claudication recurrence. A third patient had two percutaneous redilatations of a restenosis. The remaining 11 patients became free of complaints. PIER seems to be a feasible treatment for patients with chronic femoropopliteal occlusions with a very good technical success, low complication rate and promising initial clinical outcome. Follow-up studies have to prove its superiority over the established revascularisation techniques.

[Cockett syndrome. Initial results with percutaneous treatment in 6 patients]. / Het syndroom van Cockett. Initiële ervaring met percutane behandeling in 6 patiënten.

Intimal hypertrophy with venous spur formation caused by compression of the left common iliac vein by the right common iliac artery is advanced as the etiology of the higher incidence of deep venous thrombosis involving the left leg. In most cases of left iliofemoral thrombosis no underlying compression syndrome is detected or treated because the left common iliac vein has to be cleared from thrombi before compression can be identified. A series of 6 consecutive retrospectively analyzed patients with acute left iliofemoral thrombosis is presented. In these patients a left iliac vein compression syndrome was detected after percutaneous intraluminal thrombolysis with Actilyse (rt-PA). This compression was successfully relieved by insertion of a wall stent. Percutaneous treatment of Cockett's syndrome seems an attractive alternative for conservative and/or surgical management.

Nonlinear superchiral meta-surfaces: tuning chirality and disentangling non-reciprocity at the nanoscale.

Circularly polarized light is incident on a nanostructured chiral meta-surface. In the nanostructured unit cells whose chirality matches that of light, superchiral light is forming and strong optical second harmonic generation can be observed.