Edge-emitting polariton laser and amplifier based on a ZnO waveguide.

We demonstrate edge-emitting exciton-polariton (polariton) laser operation from 5 to 300 K and polariton amplifiers based on polariton modes within ZnO waveguides. The guided mode dispersion below and above the lasing threshold is directly measured using gratings placed on top of the sample, fully demonstrating the polaritonic nature of the lasing modes. The threshold is found to be smaller than that expected for radiative polaritons in planar ZnO microcavities below 150 K and comparable above. These results open up broad perspectives for guided polaritonics by enabling easier and more straightforward implementation of polariton integrated circuits that exploit fast propagating polaritons, and, possibly, topological protection.

From excitonic to photonic polariton condensate in a ZnO-based microcavity.

We report exciton-polariton condensation in a new family of fully hybrid ZnO-based microcavity demonstrating the best-quality ZnO material available (a bulk substrate), a large quality factor (~4000) and large Rabi splittings (~240 meV). Condensation is achieved between 4 and 300 K and for excitonic fractions ranging between 17% and 96%, which corresponds to a tuning of the exciton-polariton mass, lifetime, and interaction constant by 1 order of magnitude. We demonstrate mode switching between polariton branches allowing, just by controlling the pumping power, to tune the photonic fraction by a factor of 4.

Double-incision mini-invasive technique for BTB harvesting: its superiority in reducing anterior knee pain following ACL reconstruction.

BACKGROUND: Arthroscopically-assisted ACL-reconstructions are currently reliable, reproducible and thoroughly used methods. Residual anterior knee symptoms however, especially after patellar-BTB graft use, are not uncommon occurrences following ACL-reconstructions, and can downgrade patient's satisfaction. Anterior knee pain contributing factors are numerous and include injury to the saphenous nerve infrapatellar branches (SNIB) and/or histologic changes at the harvest site. We thus preferably suggest a double-incision minimal approach for the patellar transplant harvesting stage in order to prevent injury to the SNIB. HYPOTHESIS: This technical variation decreases the risk of injury to the saphenous nerve infrapatellar branches while preserving the peritenon. STUDY DESIGN: Prospective controlled trial. MATERIAL AND METHODS: Two groups were alternatively constituted in 2004: ligament reconstructions were either performed via a two-incisions approach during the first 2004 semester or via a single-incision approach during the second 2004 semester. Pain, even at a mild level, was evaluated. Patients were assessed using objective pain provocative tests and sensory assessment, a Lille University femoropattelar score, the IKDC Knee evaluation, the SF36 quality of life score in combination with radiographic and ultrasonographic investigations. RESULTS: Forty patients were reviewed at a mean 33 months follow-up delay: 21 of these had a double-incision approach and 19 had a single-incision approach. Four patients from the double-incision sub-group and 11 from the single-incision sub-group reported anterior knee pain (p<0.01). The knee-walking test came out normal in 11 patients from the double-incision sub-group and in three from the single-incision sub-group (p<0.02). The Lille University patello-femoral score was 91/100, demonstrating no significant difference. At follow-up, sensory disorders were observed in 17 patients from the single-incision sub-group and in nine from the double-incision sub-group (p<0.002). However, no statistical correlation could be established between anterior knee pains and sensorial disturbances. SF36 and IKDC objective and subjective scores were similar in both groups. Ultrasonographic findings revealed a lesser degree of patellar tendon thickening in the double-incision sub-group. However, no statistically significant differences definitely emerged between the two groups (p=0.50). DISCUSSION: The results of this study strongly support our main hypothesis: The double-incision approach significantly reduces the mid-term incidence of anterior knee pains after ACL-reconstructions. Additionally, this technical variation markedly decreased the occurrence of sensory disorders and the extent of hypoesthesia. We thus advocate the use of a double-incision graft harvesting technique in ACL-reconstructions using a patellar-bone-tendon-bone transplant.

Resonant light delay in GaN with ballistic and diffusive propagation.

We report on a strong delay in light propagation through bulk GaN, detected by time-of-flight spectroscopy. The delay increases resonantly as the photon energy approaches the energy of a neutral-donor bound exciton (BX), resulting in a velocity of light as low as 2100 km/s. In the close vicinity of the BX resonance, the transmitted light contains both ballistic and diffusive components. This phenomenon is quantitatively explained in terms of optical dispersion in a medium where resonant light scattering by the BX resonance takes place in addition to the polariton propagation.

[Femoral revision using cemented stem and compacted bone graft: femoral migration analysis]. / Reprise fémorale par tige cimentée et greffe morcelée compactée: analyse de la migration fémorale.

PURPOSE OF THE STUDY: If the bone loss is significant, revision total hip arthroplasty can be most difficult. We present a series of 30 patients with major loss of bone stock treated with the X-change (Exeter) technique for revision total hip arthroplasty. MATERIAL AND METHODS: This prospective consecutive series included 30 reconstructions performed between 1996 and 2001. Compacted grafts with cryopreserved bone were used. Mean follow-up was 42 months (range 24-80). According to the SOFCOT classification, bone loss was stage II in one patient, stage III in 14 and stage IV in 15. The technique described by Gie, Linder and Ling was rigorously applied: smooth stem, no force on the Merckel, cement in the impacted allograft, filling of femoral bone defects. Reinforcement with plates, mesh, or wire was used as necessary to bridge cortical defects. The Postel-Merle-d'Aubigné (PMA) score was used to assess clinical outcome. Digital x-rays were obtained before and after surgery and at last follow-up to assess implant position (vertical migration and frontal deviation), changes in bone stock, and the Pierchon classification. Thirty patients were seen at two years follow-up. Two patients were lost to follow-up after two years. Material had to be removed in two patients because of mechanical intolerance. There was one postoperative fracture at six months. One patient died more than two years after implantation. The PMA score improved from 11 to 17 at last follow-up. Radiographic results showed mean 7.3 mm stem migration and mean 2 degrees frontal deviation which were not correlated with clinical presentation. The Pierchon classification revealed 20 situations of corticalization and eight of trabeculation. Factors affecting migration were modalities of graft preparation and time to first weight bearing. Migration was unchanged after twelve months. DISCUSSION AND CONCLUSION: The functional and radiographic results remained satisfactory in light of the initial bone loss. Implant migration did not affect outcome. We have modified the surgical technique in line with these results, particularly concerning preparation of the impacted bone graft. This technique has the advantage of filling bone defects and avoiding therapeutic escalation.

Mie resonances, infrared emission, and the band gap of InN.

Mie resonances due to scattering or absorption of light in InN-containing clusters of metallic In may have been erroneously interpreted as the infrared band gap absorption in tens of papers. Here we show by direct thermally detected optical absorption measurements that the true band gap of InN is markedly wider than the currently accepted 0.7 eV. Microcathodoluminescence studies complemented by the imaging of metallic In have shown that bright infrared emission at 0.7-0.8 eV arises in a close vicinity of In inclusions and is likely associated with surface states at the metal/InN interfaces.

Arabidopsis contains at least four independent blue-light-activated signal transduction pathways.

We have investigated the stomatal and phototropic responses to blue light of a number of single and double mutants at various loci that encode proteins involved in blue-light responses in Arabidopsis. The stomatal responses of light-grown mutant plants (cry1, cry2, nph1, nph3, nph4, cry1cry2, and nph1cry1) did not differ significantly from those of their wild-type counterparts. Second positive phototropic responses of etiolated mutant seedlings, cry1, cry2, cry1cry2, and npq1-2, were also similar to those of their wild-type counterparts. Although npq1 and single and double cry1cry2 mutants showed somewhat reduced amplitude for first positive phototropism, threshold, peak, and saturation fluence values for first positive phototropic responses of etiolated seedlings did not differ from those of wild-type seedlings. Similar to the cry1cry2 double mutants and to npq1-2, a phyAphyB mutant showed reduced curvature but no change in the position or shape of the fluence-response curve. By contrast, the phototropism mutant nph1-5 failed to show phototropic curvature under any of the irradiation conditions used in the present study. We conclude that the chromoproteins cry1, cry2, nph1, and the blue-light photoreceptor for the stomatal response are genetically separable. Moreover, these photoreceptors appear to activate separate signal transduction pathways.

Two-dimensional protein patterns of Arabidopsis wild-type and auxin insensitive mutants, axr1, axr2, reveal interactions between drought and hormonal responses.

In order to detect gene products involved in Arabidopsis drought adaptive strategy, 2D-PAGE protein patterns of two auxin-insensitive mutants, axr1, axr2, differentially affected in specific drought responses, were compared to the wild-type Columbia ecotype, in well-watered and drought-stressed conditions. Coupled to computer analysis of polypeptide amounts, 2D-electrophoresis revealed subtle changes in protein expression induced by progressive drought stress and/or mutations affecting the auxin response pathway. The differential protein patterns of axr1 and axr2 were consistent with their contrasting drought responses. The specific leaf and root protein patterns of axr1 showed that this mutation disrupts drought responses related to auxin regulation. In particular, the near absence of drought rhizogenesis in axr1 was associated with a root protein pattern closer to the well-watered than to the water-stressed axr2 and Columbia wild-type root protein patterns. Also, the largely different effects of axr1 and axr2 mutations suggest that they affect different pathways in auxin response. Several sets of polypeptides, whose regulation was affected by drought and/or mutation, were thus detected. These polypeptides could play a role both in the auxin and the drought response pathways. Their identification, through microsequencing, should be most informative.

Nucleotide sequences of four pathogen-induced alfalfa peroxidase-encoding cDNAs.

We constructed an alfalfa cDNA library from mRNA extracted from leaves after infection with Pseudomonas syringae (incompatible interaction). Screening with oligodeoxyribonucleotides designed from regions conserved in all known peroxidases allowed the isolation of four cDNAs (Msprx1A, 1B, 1C and 2). Sequence analysis revealed the presence of open reading frames of 351, 355, 358 and 323 amino acids, respectively, with the characteristic consensus sequences of plant peroxidases. Sequence comparison showed that the Msprx2 product is significantly different from the others and, particularly, lacks a C-terminal propeptide which might be required for vacuolar targeting.

[Frequency of angiographic restenosis after 6 months and long-term outcome of coronary angioplasty]. / Fréquence des resténoses angiographiques à 6 mois et devenir à long terme après angioplastie coronaire.

Five hundred patients with a mean age of 59 years were followed up for an average of 32 months after coronary angioplasty. All patients were included in a prospective study comprising coronary angiography at 6 months for 379 patients (91% primary successes). The long-term outcome was evaluated by a questionnaire or telephone interview in all cases. The global primary success rate was 84.4% in this series. The primary failures include 1.8 fatalities, 0.6% myocardial infarction, 2% emergency coronary bypass surgery and 11.2% without immediate clinical consequences. At 6 months, there were 48% of restenoses (182/379 patients) and 28% underwent immediate repeat angioplasty (141/500 patients) with a primary success rate of 91%. After the repeat angioplasty, the restenosis rate was 43% but this varied according to the time from the first restenosis: 60% when the interval was short (under 2 months) compared with 21% when the interval was 6 months (p < 0.01). The actuarial survival rates at 4 years were 95% after successful angioplasty 96% after uncomplicated failures or medically treated restenosis and 98% after bypass surgery. The predictive factors for secondary death were age of over 70 years, previous non-thrombolized myocardial infarction and complications of angioplasty. The long-term outcome was good despite the 48% 6 months restenosis rate requiring revascularisation procedure in 73% of cases.

Glaphenine-containing gallstones.

Glaphenine is an analgesic drug derived from anthranilic acid. We report the analytical procedures for stone analysis in three cases of common bile duct stones containing glaphenic acid, which developed in arthrosic patients treated for 13.7 +/- 5 years with glaphenine. Stone analysis was performed by infrared spectroscopy, high performance thin layer chromatography, scanning electron microscopy and energy dispersive X-ray analysis. Mechanisms of lithogenesis are discussed. These observations emphasize the possibility of radiolucent gallstones mainly composed of drug compounds.

[Colonic duplication disclosed in adults. A case]. / Duplication colique découverte chez l'adulte. Un cas.

We report about one case of asymptomatic duplication of the colon, which was diagnosed with a barium enema in an adult. This condition is rare, especially in the tubular form such as described in this case. The discussion is associated to a review of the literature.

[Perception errors in detecting advanced colorectal cancers using a double-contrast enema]. / Erreurs de perception dans la détection des cancers rectocoliques évolués en lavement double contraste.

The authors provide a didactic analysis of the errors in perception that can lead to false-negative findings in the detection of advanced rectocolonic cancers with double-contrast enema. They consider 5 categories of images as typical, ie. transverse or horizontal linear opacities, abnormal lumen due to haustral folds on semiaxial views, "pool sign", amputation of the cecum and irregular hypertrophy of the ileocolic valve. These mistakes will become exceptional if the double-contrast images are studied thoroughly using precise rules, and the percentage of false-negative findings in the detection of rectocolonic cancers should thus be reduced to 1%.

[Left ventricular ejection impediment during mitral valve replacement. Apropos of a case after insertion of a Carpentier-Edwards bioprosthesis]. / Gêne à l'éjection ventriculaire gauche lors des remplacements valvulaires mitraux. A propos d'une observation après mise en place d'une bioprothèse de Carpentier-Edwards.

Left ventricular ejection impediment is one of the complications of mitral valve replacement, especially in case of isolated mitral stenosis with small left ventricle. The use of a "low profile" valve does not prevent this complication. The diagnosis is based on catheterization but the advent of the ultrasound-Doppler may make it easier.

[Quantitative evaluation of myocardial ischemia using imaging methods]. / Evaluation quantitative de l'ischémie myocardique par les méthodes d'imagerie.

Secondary prevention of myocardial infarction includes all measures likely to reduce morbidity and mortality after the infarction. It is a highly heterogeneous concept applied to a highly heterogeneous disease. The natural history of myocardial infarction, which must be known to determine the frequency of critical events and hence devise a trial, is incomplete particularly since treatment capable of altering this history (aorto-coronary bypass, thrombolysis) have been introduced. Future trials in secondary prevention of myocardial infarction must concentrate on such important questions as: can the possibilities of reperfusion be extended as regards the acute phase, and which preventive measures are useful to patients at high risk post-infarction? The A.P.S.I. study (acetolol in the secondary prevention of myocardial infarction) is an example of study aimed at answering the second question.

[Bepridil and torsades de pointes. Apropos of 11 cases]. / Bépridil et torsades de pointes. A propos de 11 observations.

The authors report 11 cases of spikes occurring under bepridil treatment. It concerns an elderly population, predominantly female, receiving most of the time 300 mg of bepridil. The frequency of associated hypokalemic or arrhythmic medications is emphasized. The comparison of these results to those from other series in the literature, enables to propose precautions for the use of this molecule.

[Pneumopathy caused by amiodarone. An often unrecognized iatrogenic entity]. / Pneumopathie à l'amiodarone. Une entité iatrogène sovent méconnue.

Three cases of interstitial pneumopathy secondary to amiodarone are reported, in addition to almost 200 cases previously published in the literature. The main clinical, radiological, biological and evolutive characteristics are reminded in emphasizing the advantages of bronchioalveolar irrigation. Some factors seem to be predisposing, without any definite proof however. They are: high daily dosage, long term treatment, high cumulative dose, concomitant ingestion of another anti-arrhythmic medication, especially in elderly patients, and in patients who, before any treatment, presented a decreased total pulmonary capacity and a CO transfer capacity lower than 80 p. cent of the theoretical values. Discontinuation of amiodarone and administration of steroids usually produce a rapid regression of the clinical and radiological symptoms.