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The voltage‐tunable electroluminescence (VTEL) observed on porous silicon‐electrolyte system is investigated in relation with the material photoluminescence (PL). It is shown that the PL line is the envelope of all the emitted EL spectra obtained upon the bias variation. Consequently, a blueshift of the (PL) line leads to a similar shift of all the corresponding EL lines. This strongly suggests a common origin of these two phenomenon. Moreover, this study seems to indicate that the VTEL of porous silicon is related to the size and efficiency distributions of the silicon nanocrystallites associated with an electrically induced selective carrier injection.

From a 83 min long sequence of observations of Ca II K and He I (1083 nm) line profiles, some dynamical properties of the main components of the quiet upper chromosphere are derived: for both the magnetic network and the internetwork, amplitude and phase spectra of the Doppler velocities are presented.

Starting from our extensive numerical modeling of the NLTE conditions in solar prominences, we present here some examples of important correlations between the prominence plasma parameters and radiation properties. For example, the plasma emission measure was found to be closely related to the integrated Hα line intensity which provides a new diagnostic tool for determination of plasma densities.

Comparison between HETC and COSMIC codes shows that COSMIC code, although being a protons-silicon interaction code, can be used to calculate the energy deposited by high energy neutrons in silicon.

We established anti-ganglioside antibody profiles in GBS and studied the frequency, fine specificity and clinical correlate. IgG and IgM antibodies to 8 gangliosides were tested by immunodot-blot in 249 consecutive patients with Guillain-Barré syndrome with large variability in clinical expression, referred to our laboratory over a 8-year period. IgG and IgM anti-GM1 antibodies were measured by Elisa. Thin-layer chromatography overlayed by serum was used to control positivity. 89/249 GBS (36%) had characteristic anti-ganglioside antibody profile. Isotypes were, IgG (62%), IgG + IgM (26%) and IgM (12%). Antecedent infections were found in 62% of GBS included more frequently Campylobacter jejuni and cytomegalovirus. Various autoantibody profiles were described with an immunodominant ganglioside. We detected 6 characteristic anti-ganglioside profiles with fine specificity and immunodominant ganglioside corresponding to 6 immuno-clinical variants of GBS: 1) anti-GM1 and GD1b IgG and IgGIgM in the acute motor axonal neuropathy after Campylobacter jejuni infection in 41 GBS; 2) anti-GD1a IgG in 6 severe motor axonal GBS after Campylobacter jejuni infection; 3) selectively anti-GQ1b IgG in 17 typical Miller Fisher syndrome with areflexia, ataxia and ophthalmoplegia; 4) anti- GT1b ganglioside and polysialogangliosides IgG (n = 9) in two separate cranial nerve variants, ophthalmoplegic SGB and lower cranial nerve variants depending upon the presenting deficit; 5) anti-GD1b IgG in 5 pure ataxic sensory GBS (4%); 6) anti-GM2 IgM in 11 severe GBS with antecedent CMV infection (8%). 34 GBS (14%) had low levels of anti-GM1 and GD1b IgM antibodies which are not disease specific and may simply represent part of the naturally occurring autoantibody population or a secondary response to disease. 126 GBS (50%) had no antibodies, predominantly in classical form. Associations between isotype, fine specificity and clinical presentation permit the definition of homogeneous immuno-clinical variants. Various autoantibody profiles with diagnostic and prognostic value are easy to perform by immunodot blot in acute peripheral neuropathies.

Serum IgM and IgG autoantibodies against carbohydrate epitopes on glycolipids and glycoproteins have been determined in a series of 112 neuropathies associated with monoclonal IgM (M-IgM) by different immunological techniques. The M-IgM anti-myelin sheath antibodies were determined by indirect immunofluorescence microscopy, the M-IgM anti-myelin associated glycoprotein (MAG) antibodies by western-blot analysis, the M-IgM anti-SGPG and SGLPG antibodies by immunodetection on thin-layer chromatography, the M-IgM anti-ganglioside GM3, GM2, GD3, GM1, GD1a, GD1b, GT1b, GQ1b and anti-sulfatide antibodies by immunodot-blot assay on membrane. Among the 112 M-IgM, 81 had autoantibody activity against nerve glycolipid antigens concentrated in peripheral nerve (72%). M-IgM bound strongly to myelin sheath in 34,5% of cases, to MAG in 38% of cases, to SGPG/SGLPG in 52% of cases, to gangliosides in 21.5% of cases and to sulfatide in 26 % of cases. Six M-IgM autoantibody activity profiles have been described in correlation with distinct clinical syndromes: - the M-IgM autoantibody activity profile against the carbohydrate epitope common to the glycolipids SGPG and SGLPG and myelin associated glycoprotein (MAG) in chronic demyelinating sensitive and sensorimotor peripheral neuropathies (58 patients, 52%); - the M-IgM autoantibody activity profile against immunodominant GM1 in demyelinating pure motor neuropathies (9 patients, 8%); - the M-IgM autoantibody activity profile against immunodominant disialosylgangliosides in chronic demyelinating sensitive ataxic neuropathies (8 patients, 7%); - the M-IgM autoantibody activity profile against immunodominant GM2 in demyelinating motor polyneuropathies (3 patients, 2.5%); - the M-IgM autoantibody activity profile against immunodominant GD1a in pure motor polyneuropathies (2 patients, 2%); - the M-IgM autoantibody activity profile against immunodominant GT1b and polysialosylgangliosides in one acute polyradiculoneuropathy (1%). The M-IgM recognized all gangliosides except GM1 and GM2. The neuropathies associated with IgM monoclonal gammopathy with autoreactive specificity form distinct syndromes. In 27.5% of cases, M-IgM had no identifiable activity autoantibodies.

We investigated whether adenosine, a potent contributor to the regulation of pulmonary function, can modulate human lung mast cell (HLMC) fibrinolytic activity. Tissue plasminogen activator (tPA) activity and tPA transcript expression levels from a human mast cell line (HMC-1) and HLMC were monitored following adenosine application. Adenosine potentiated mast cell tPA activity and tPA gene expression in a dose-dependent manner. Adenosine effects were abolished in the presence of adenosine deaminase. HMC-1 cells predominantly expressed adenosine A 2A and A 2B receptor transcripts (A 2A >>A 2B >A 3 >>A 1 ). In addition to A 2A and A 2B , A 3 receptor transcripts were also abundantly found in HLMC (A 2A >>A 2B >>A 3 >>A 1 ). Pharmacological and signalling studies suggest that the A 2A receptor is the major subtype accounting for adenosine-induced mast cell tPA activity. Finally, the supernatant from HMC-1 cells treated with adenosine (24h) significantly increased fibrin clot lysis, while ZM241385, an A 2A receptor antagonist, abolished this effect. This study provides the first data to demonstrate the potentiating effect of adenosine on mast cell tPA activity and fibrin clot lysis.

Spectral holeburning and fluorescence excitation spectroscopy has been used to measure the interaction between pairs of Nd 3+ ions in CsCdBr 3 . The magnetic splitting factors of single Nd 3+ ions were obtained from spectral holeburning of Nd 3+ ions associated with non-magnetic Pr 3+ ions in Nd-Pr pairs, supplemented by a crystal field calculation. From this the magnetic dipole coupling of the pair was calculated to be within a factor of two of that observed experimentally.

1. We have used subtype selective P2X receptor antibodies to determine the expression of P2X(1 - 7) receptor subunits in the mouse urinary bladder. In addition we have compared P2X receptor mediated responses in normal and P2X(1) receptor deficient mice to determine the contribution of the P2X(1) receptor to the mouse bladder smooth muscle P2X receptor phenotype. 2. P2X(1) receptor immunoreactivity was restricted to smooth muscle of the bladder and arteries and was predominantly associated with the extracellular membrane. Diffuse P2X(2) and P2X(4) receptor immunoreactivity not associated with the extracellular membrane was detected in the smooth muscle and epithelial layers. Immunoreactivity for the P2X(7) receptor was associated with the innermost epithelial layers and some diffuse staining was seen in the smooth muscle layer. P2X(3), P2X(5) and P2X(6) receptor immunoreactivity was not detected. 3. P2X receptor mediated inward currents and contractions were abolished in bladder smooth muscle from P2X(1) receptor deficient mice. In normal bladder nerve stimulation evoked contractions with P2X and muscarinic acetylcholine (mACh) receptor mediated components. In bladder from the P2X(1) receptor deficient mouse the contraction was mediated solely by mACh receptors. Contractions to carbachol were unaffected in P2X(1) receptor deficient mice demonstrating that there had been no compensatory effect on mACh receptors. 4. These results indicate that homomeric P2X(1) receptors underlie the bladder smooth muscle P2X receptor phenotype and suggest that mouse bladder from P2X(1) receptor deficient and normal animals may be models of human bladder function in normal and diseased states.

Ocular neuromyotonia in the muscles innervated by the right oculomotor nerve was diagnosed in a patient without a history of radiation therapy. Electromyography of the levator palpebrae showed continuous motor unit activity. Brain MRI disclosed a close contact between the right third cranial nerve and a basilar artery dolichoectasia. The patient partly benefited from carbamazepine therapy. This unique finding suggests that neurovascular compression syndrome could be an hitherto unrecognised cause of ocular neuromyotonia.

We studied the percentage change in compound muscle action potential (CMAP) amplitude and area during and after a 5-min maximal contraction of the muscle. The exercise test (ET) was performed on 64 patients with different muscle disorders and on 46 normal controls. The range of normal ET values was defined as the mean + 2 SD of the control values. The mean sensitivity of the test was 63% in the whole group with ion channel muscle disorders, the highest sensitivity being seen in primary periodic paralysis (81%) and the lowest in chloride channelopathies (17%). In thyrotoxic periodic paralysis, the ET was abnormal in the three of the four patients studied. In patients with myotonic dystrophy, a smaller than normal increase in CMAP amplitude occurred during and after exercise, whereas in proximal myotonic myopathy a normal initial increase in CMAP amplitude was followed by an abnormal decrement. We conclude that the ET can be of use in confirming abnormal muscle membrane excitability in patients with calcium and sodium channelopathies and thyrotoxic periodic paralysis. In chloride channelopathy, the test may also be abnormal, but shows no, or only a small, increase in amplitude or area in the immediate postexercise period. The test may also be abnormal in proximal myotonic myopathy, but is normal in myotonic dystrophy.

We report clinical, genetical and genealogical findings in 149 French families from the Rhône-Alpes area studied over a 5-year period. There was a significant excess of DM females compared to DM males with (CTG) repeat sizes between 1-2 kb. The mean maternal (CTG) repeat size was higher than paternal repeat size. Anticipation phenomenom was significantly higher after maternal than after paternal transmission. A significant correlation between parental (CTG) repeat size and intergenerational variation both in paternal and maternal transmissions was observed. The anticipation phenomenom was more important for sons than daughters particularly after maternal transmission. The mean (CTG) repeat size in mothers of CDM cases was about twice that of mothers of NCDM children. The risk of giving birth to a CDM child increased considerably when the number of maternal (CTG) repeats was over 300 (CTG). A significant excess of DM females was observed. They had on average 24% fewer children than male patients. Paternal transmission (63.6%) of DM occurred more frequently than maternal transmission (52.7%).

We retrospectively evaluated measurement data and clinical relevance of autoantibodies to gangliosides in peripheral neuropathies (PN). The IgG and IgM antiganglioside autoantibodies were determined by our own immunodot-blot assay on membrane and by enzyme-linked immunosorbent assay (Elisa) in sera of 1,342 patients with peripheral neuropathies. Anti-GM1 and anti-GD1b autoantibodies formed a part of the normal autoantibody repertoire and were common place in 12% of normal subjects and in 14% of disease control groups. Polyclonal IgM antiganglioside autoantibodies were detected in chronic PN, polyclonal IgG antiganglioside autoantibodies were detected in acute PN. Polyclonal IgM anti-GM1 and anti-GD1b autoantibodies were detected in 35 patients out of 48 with treatable multifocal motor neuropathy with persistent conduction blocks. These autoantibodies well discriminated between suspected motor peripheral neuropathies and motor neuron diseases (sensitivity 73%, specificity 83%, positive predictive value 60%, negative predictive value 91%). Monoclonal IgM autoantibodies reacted strongly with gangliosides in 15 patients out of 77 with M-IgM neuropathy (19%). M-IgM autoantibodies differed in their fine specificities with different principal target antigens as demonstrated with cross-reactivity. Such findings provide further evidence for a relationship between neurological syndromes and antiganglioside antibody profiles and also suggest that different gangliosides could be principal target antigens such as GM1, GD1b, GT1b, GD1a or GM2. Polyclonal IgG anti-GM1 and anti-GD1b autoantibodies were detected in 21 patients out of 22 with acute motor axonal Guillain-Barré syndrome with antecedent of infection by Campylobacter jejuni, polyclonal IgG anti-GQ1b autoantibodies in 9 patients out of 10 with Miller-Fisher syndrome. Detection of antiganglioside autoantibodies by immunodot-blot assay which is simple and quick in testing a large panel of gangliosides has become very important in the diagnosis and in the choose of expensive therapeutic strategies in chronic or acute autoimmune neuropathies.

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Unlike the slow band (S-band), there is currently no clear spectroscopic signature which links the fast band (F-band) to the Si nanostructure. Time resolved photoluminescence (TRPL) was employed in the present work to study the porous silicon photoluminescence decay behavior in the nanosecond range, namely the F-band. Measurements were performed at room temperature on oxidized and fresh porous silicon samples. It was shown that the fast (ns) component had an extrinsic origin for oxidized samples, while the fresh samples exhibited an intrinsic behavior for both the fast and slow (10 μs) components. The excitation intensity dependence of the PL intensity was studied and showed different behavior of the F-band in both oxidized and fresh samples.

High-resolution optical holeburning is used to characterize the tunneling potential of delocalized protons in benzoic acid dimers coupled to a dye molecule. The effect of pressure on the system is measured and the relaxation rates between the tunneling levels are determined from the homogeneous linewidths.

Alfven waves represent one of the most prominent ways of heating the solar corona and accelerating the solar wind. One of their signatures is to broaden the spectral lines in excess of their thermal width. Here we aim to combine observations of non-thermal broadenings measured by SUMER in OVI (1037.6 A) line and electronic densities derived from white-light observations during the 1998 total eclipse. After checking the validity of the frequently-used assumption of equal ion and electron temperatures, we compute the variation of the non-thermal velocity as a function of height in an interplume region within the south polar coronal hole.

Thin layers of poly(dihexylfluorene-co-N-hexylcarbazole) sandwiched between ITO and aluminium electrodes show stable photoluminescence and electro-luminescence at room temperature and ambient atmosphere. I(V) and Electro-luminescence versus voltage curves present a much lower threshold than device made up of poly(dihexylfluorene) homopolymer. When using the copolymer, the barrier height for hole injection is reduced to a value close to 0.17 eV to be compared to 0.83 eV for the homopolymer. This difference in offsets has been confirmed by electrochemical investigations.

Miller-Fisher syndrome is defined by the triad: ophthalmoplegia, ataxia and areflexia. This rare entity is generally regarded as a variant of the Guillain-Barré syndrome, although neurophysiological patterns differ. In the acute phase of the disease, sera of affected patients contain high titers of antiganglioside anti-GQ1b, which is a specific marker. Recurrences are exceptional.We report the case of a man with three recurrences of Miller-Fisher syndrome within 16 years. Anti-GQ1b antibody titers were elevated during an episode, decreasing but not completely and vanishing 2 years later. Intravenous human immunoglobulin treatment probably accelerated improvement at the two last episodes.Some experimental and immunohistochemical data from the literature argue for a probable direct pathogenic role of antibodies against GQ1b ganglioside in this syndrome. This should be a rationale for the use of immunomodulating treatments.

The arm is particularly vulnerable to neurological injury, due to the intimate anatomical relationship between the brachial plexus and the traction zones. Severe injuries of the brachial plexus can be caused by compression, traction or laceration. Fortunately, many deficits are superficial and permanent neurovascular deficits are rare. Nevertheless, it is important to identify the probable cause of the injury since the prognosis for recovery directly depends on the underlying nature of the neurological deficit. Two anaesthetised children who suffered brachial plexus injury during cardiac catheterisation are reported. The first, with Ebstein's anomaly and significant pulmonary valve stenosis, presented, after the procedure, with a right arm motor deficit with proximal predominance. The second patient, with tetralogy of Fallot and pulmonary atresia, presented difficulty in left arm abduction and external rotation on awakening. The risk factors for brachial plexus lesions during anaesthesia are discussed. These include improper positioning, anaesthetic agents, extreme variations of body mass index and anatomical anomalies. Prevention, evolution and treatment of the brachial plexus injury are also considered. With proper care by the cardio-radiologist and anaesthesiologist the frequency of this injury can be reduced.

The human P2Y1 receptor heterologously expressed in Jurkat cells behaves as a specific adenosine 5'-diphosphate (ADP) receptor at which purified adenosine triphosphate (ATP) is an ineffective agonist, but competitively antagonizes the action of ADP. This receptor is thus a good candidate to be the elusive platelet P2T receptor for ADP. In the present work, we examined the effects on ADP-induced platelet responses of two selective and competitive P2Y1 antagonists, adenosine-2'-phosphate-5'-phosphate (A2P5P) and adenosine-3'-phosphate-5'-phosphate (A3P5P). Results were compared with those for the native P2Y1 receptor expressed on the B10 clone of rat brain capillary endothelial cells (BCEC) and for the cloned human P2Y1 receptor expressed on Jurkat cells. A2P5P and A3P5P inhibited ADP-induced platelet shape change and aggregation (pA2 = 5) and competitively antagonized calcium movements in response to ADP in fura-2-loaded platelets, B10 cells, and P2Y1-Jurkat cells. In contrast, these compounds had no effect on ADP-induced inhibition of adenylyl cyclase in platelets or B10 cells, whereas known antagonists of platelet activation by ADP such as Sp-ATPalphaS were effective. These identical signaling responses and pharmacologic properties suggest that platelets and BCEC share a common P2Y1 receptor involved in ADP-induced aggregation and vasodilation, respectively. This P2Y1 receptor coupled to the mobilization of intracellular calcium stores was found to be necessary to trigger ADP-induced platelet aggregation. The present results, together with data from the literature, also point to the existence of another as yet unidentified ADP receptor, coupled to adenylyl cyclase and responsible for completion of the aggregation response. Thus, the term, P2T, should no longer be used to designate a specific molecular entity.

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Time resolved photoluminescence (PL) measurements are performed on oxidized and fresh porous silicon at room temperature. Comparing the evolution of the nanosecond time delayed PL in both cases, a new feature of the PL spectra is identified: the fast-red band, present as well in fresh or aged samples. The nonlinear excitation intensity dependence of this component is described by a simple model where, the Auger effect inside isolated silicon nanocrystallites plays the dominant role.

Excellent review papers have been presented in this session by S. Solanki (Manifestations of solar magnetic fields), K. Dere (Coronal Mass Ejections and interplanetary ejecta) and W. Droege (Particle acceleration by waves and fields) and the relevant texts can be found in this volume.

Incubation of dimeric MM-creatine kinase (MM-CK) with high NaCl or LiCl concentrations results in dissociation of the subunits and complete enzyme inactivation. In NaCl, this process, which depends on protein concentration, may be described according to a two-state model where the dimer can be reversibly converted into compact folded monomers (D--2M). At LiCl concentrations higher than 2-2.5 M, MM-CK is recovered in two monomeric states: an inactive compact species (M) and a more expanded form (EF), which represents 15-20% of the population. Thus, in LiCl, a three-state model (D--2M --2EF) more adequately accounts for our experimental results. The monomeric species (M) obtained in NaCl and LiCl exhibits some properties of the molten globule state described in guanidine hydrochloride. Indeed, this form is compact and devoid of any enzymatic activity; it maintains a high degree of secondary structure and binds 8-anilino-1-naphthalenesulfonate. The formation of this intermediate induces the exposure of a second tryptophan (among the four present) which is located at the monomer-monomer interface in the native structure. In LiCl, the monomeric species (M) is irreversibly converted into a less compact form (EF) which seems to have lost a large part of its secondary structure.

We report three cases presenting mainly with neck extensor weakness, or dropped head syndrome, revealing respectively myasthenia gravis, amyotrophic lateral sclerosis and non-inflammatory neck extensors myopathy. We discuss the different diagnosis of this rare syndrome and this late onset localized myopathy of unknown etiology.

We have performed a molecular analysis of the androgen receptor gene in two families with suspected Kennedy's disease (spinal and bulbar muscular atrophy, SBMA) with the aim of making a firm diagnosis of the disease. The 2 patients studied were sporadic cases. Both presented clinical signs compatible with the diagnosis of SBMA: limb and facial muscular weakness of adult onset progressing toward muscular atrophy. Clinical signs of partial androgen insensitivity syndrome usually observed in SBMA were present only in patient 2. Enzymatic amplification of the CAG repeat region of exon 1 of the androgen receptor gene was performed on genomic DNA. PCR products were submitted to agarose or acrylamide electrophoresis for size evaluation. Precise determination of the CAG number was performed by direct sequencing of purified amplification products. Androgen receptor gene analysis was also performed in 2 sisters of patient 1 and in the mother, sisters and daughter of patient 2. Androgen receptor-binding activity was also determined on cultured genital skin fibroblasts of patient 1. Analysis of PCR products showed in both patients a single band that was much larger in size than the control. The expansion of the CAG repeat number was confirmed by direct sequencing: the exact number of CAG was 47 in patient 1 and 42 in patient 2 (n = 12-32). The 2 studied sisters of patient 1 did not present the abnormal fragment, demonstrating they are not carriers for the disease. Conversely, the mother, sisters and daughter of patient 2 presented both normal and mutated alleles. The migration of the labelled PCR products on a sequencing gel revealed a meiotic instability of expanded CAG repeat in family 2. Moreover, patient 1 had a decreased androgen-binding capacity on cultured genital skin fibroblasts. In both families, analysis of the androgen receptor gene permitted us to diagnose SBMA in the patients and to establish the carrier status in siblings. These results correspond to the literature data and confirm the usefulness of CAG repeat evaluation in the diagnosis of Kennedy's disease. They highlight the relationship between the androgen receptor and motoneuron growth, development and regeneration.

A white-light coronal imager called CORI to be implemented on a solar probe has been proposed by Habbal et al. (1995). Its scientific objectives concern the investigation of the solar corona and the source of the solar wind. It is aimed as a complement to the in-situ instruments. This paper presents some simulations of the images that will be recorded when observing solar structures of increasing complexity during the close encounter phase of the trajectory. These attempts should be considered as a first step towards the assessment of the full scientific capabilities of CORI and the definition of the observing strategy.

Epidemiological and clinical analyses of hemifacial spasm (HFS) are presented and pertinent literature is reviewed. A group of 61 patients with HFS treated with botulinum toxin (BT) was studied, and a structured questionnaire took into account: age at onset (range: 18–77, mean: 51.1 years) and age at time of initiation of treatment (range: 22–82, mean: 58.1 years), sex distribution (showing a female predominance: 70%), side distribution (showing a predominant involvement of the left side of the face: 67%), initiation and evolution of HFS, personal and family history, symptoms associated with HFS, and response to treatment given before BT. Data on age, sex, and side distributions on these 61 patients were compared to those obtained in a group of 50 patients with HFS who underwent operation to perform vascular decompression. All of the parameters that were analyzed in patients with HFS were compared to those obtained in patients with blepharospasm (BSP). Thus, 57 patients with BSP treated with BT were age-matched with a similar number of the patients with HFS (belonging to the group of 61 patients).

The authors report the results of a series of 75 patients operated on for hemifacial spasm by the same surgeon between October 1981 and January 1997. Microsurgical vascular decompression was performed through a retromastoid approach in contralateral position. The conflicting vessel was identified as the posterior inferior cerebellar artery in 41.3% of the cases, the anterior inferior artery in 38.6%, and the vertebrobasilar complex in 18.7%. Follow-up varied from 1 month to 13 years (with a mean duration of 5 years and 2 months). The outcome was excellent (total improvement) in 57 cases, good (75% improvement) in 11 cases, fair (75%) in 4 cases and poor in 3 cases. Neurological complications included deafness or hearing loss in 3 cases (2 occurred in the absence of intraoperative monitoring and the other during the first part of the series) and facial paralysis in 1 case. Brainstem auditory evoked potential (BAEP) intraoperative monitoring should be performed to avoid postoperative auditory complications; a marked auditory loss was observed in only 1.6% of the 60 patients of our series who underwent BAEP intraoperative monitoring.

We analyzed the photoluminescence (PL) mechanisms of porous silicon, and in particular, the origin of the PL high quantum efficiency (QE) at room temperature. For this we used postformation treatments, anodic oxidation, and hydrofluoric acid (HF) etching (known for their strong QE enhancement effect) correlated with a PL time resolved analysis. A third parameter was the temperature which, for heating above room temperature, gave a reversible quenching of the PL. All three parameters give a similar evolution of the PL decay shape, which we consider to originate from the same evolution of the carrier dynamics. Porous silicon is described as an undulating wire. The high QE at room temperature is attributed to carrier localization inside minima of the fluctuating potential along the wire; these considerations are extended to another porous material: amorphous porous silicon. Anodic oxidation and HF dissolution diminish the wire size, giving a reduction of the localization length of the carriers and progressiv...

Carpal tunnel syndrome is the most frequent entrapment neuropathy. Nerve conduction studies and electromyography are useful to appreciate the localization and the degree of nerve involvement, and help to the therapeutic management. Various electrophysiological procedures may be used and are reviewed. For each of them, positive (sensitivity and specificity) and negative points (technical difficulties, errors and false positive) are reported. A guideline is proposed.

We present experimental results obtained with a Pockels cell or passively Q-switched transvcrsc-diode-pumped Nd : YAG laser The pumping head is made of 36 QCW diode bars from Mc Donnell Douglas Corp. (4500 scries), which are closely coupled onto the Y AG rod (Crismatec). The active length and diameter of the cylindrical rod equal 10 and 6 mm. respectively. The total diodes energy is 800 mJ. when the pumping duration Tp and drive current Ip equal 400 µs and 65 A. We don't use any temperature control and the frequency is kept below a few Hertz. The diodes emission wavelength is then above 805 nm, leading to a coupling efficiency. ηc, near 70 %.

Dans le cadre de l'information et de la communication quantique, la necessite d'avoir des photons uniques monomodes et a la demande se revele cruciale. De recents travaux theoriques ont montre la possibilite de realiser des portes logiques quantiques n'utilisant que de l'optique lineaire. C'est dans ce contexte que s'insere notre travail sur l'elaboration et l'utilisation de boites quantiques semi-conductrices II-VI comme « pistolet » a photons. Des experiences de degroupement et d'interferences a 2 photons sont les premiers pas necessaires pour caracteriser notre source.

The sustained release properties of an indomethacin hard-gelatin capsule formulated with saturated polyglycolysed glycerides (Gelucire) were demonstrated in vivo. Indomethacin was selected as a model drug with very poor solubility in water and acidic media. It is known to exhibit high intersubject variability because of enterohepatic circulation. The formulation, which in vitro showed an erosion-controlled release, was compared in six human volunteers in the fed state by using a randomized cross-over design, to a standard multiple-unit diffusion-controlled pellet capsule. Close action period values (time duration with plasma levels higher than 0.5 micrograms/ml) were found for the test and the reference formulation (5.2 and 5.7 h). The time to reach peak t(max) appeared slightly shorter for the test preparation (1.75 h) than for the reference formulation (2.67 h), but the difference was not statistically significant because of the high intersubject variability (non-parametric Wilcoxon matched pair test). Again, due to the small number of subjects entered in the study (insufficient for a real bioequivalence study) equivalence could not be accepted in terms of extent and rate of absorption based on the decision procedures involving the 90% confidence interval and the two one-sided t-tests. The mean maximum plasma concentrations Cmax were 3.35 and 2.82 micrograms/ml for the test and the reference formulation respectively, with the corresponding values of the area under the plasma concentration-time curve AUC amounting to 10.14 and 11.38 micrograms h/ml. However, a simulation on 24 subjects (3 repetitions of the same data) would lead to bioequivalence of the two preparations. As for other corrosion-controlled forms, drug release from the proposed Gelucire formulation was very sensitive to hydrodynamic conditions, leading to poor in vitro-in vivo correlation, when comparison is made with a reference formulation characterized by a diffusion-controlled release. Finally, it was concluded that erosion-controlled release formulations are especially suitable for drugs, such as indomethacin, that have low solubility in water or acidic media. More generally, sustained release hard gelatin capsules with thermosetting excipients is very versatile and their preparation is very straightforward.

We performed DNA analysis in four families with hereditary neuropathy with liability to pressure palsy (HNPP). An interstitial deletion of the 17 p11.2 region was found in typically affected patients as well as in as yet asymptomatic patients. The opportunity for an individual genotyping permitted to ascertain a de novo deletion in one clinically affected case with no relevant familial history. DNA analysis thus becomes the most sensitive tool in diagnosing HNPP, since potentially affected patients may lack either informative familial history, or clinical symptoms or even suggestive EMG or histopathological data (tomaculas).

The elaboration by molecular beam epitaxy of a new luminescing Si-based material is presented, i.e. small grain polycrystalline Si/CaF 2 multi-quantum wells. The static luminescence properties are studied as a function of Si layer thickness, and the time dependent luminescence features as a function of wavelength and temperature. There is a rather striking similarity with the photoluminescence of porous Si, both in spectral position as in decay dynamics. The disappearance of the luminescence when the Si layers become too thick, and the blue-shift of the spectra when the Si layer thickness decreases, favour the quantum confinement hypothesis for the origin of the light emission. The important role of oxygen as passivating agent after ageing in air, is also pointed out.

International audience; Two important observations for porous silicon, the saturation and the voltage selective quenching of photoluminescence, are presented. Their similarities are pointed out and discussed in two phenomenological models: the saturation of the absorption and an Auger effect. The consequences of carrier accumulation in quantum crystallites are emphasized in both cases. The rate of Auger recombination in quantum crystallites is calculated theoretically and is compared to experiments. The importance of the Auger effect is then checked in the mechanisms of the voltage tunable electroluminescence

In the protist Euglena gracilis, the small subunit of the chloroplast enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase is encoded by nuclear rbcS genes and synthesized as a polyprotein precursor containing eight mature small subunit molecules. This large precursor is encoded by at least eight different nuclear genes as ascertained by transcript analysis. The structure of three rbcS genes was established and the coding sequences were found to be interrupted by many intervening sequences (IVS). Apart from the first 5' intron involved in trans-splicing, none of these IVSs obeys the GT-AG rule characteristic of introns in higher eukaryote genes. Surprisingly, these IVSs are located at identical positions within the three genes studied. Moreover, extensive sequence homologies were found between IVSs located in the same gene as well as in different genes. The sequences of these homologous IVSs differ only by inserted and/or deleted sequences. The striking conservation of the 5' and 3' regions of these IVSs is correlated to their potential secondary structures. These structures, which bring the IVS extremities together with the exon boundaries, could be involved in a novel splicing process. The second 5' IVS is shown to be excised before the addition of the spliced leader sequence to the pre-mRNA. Similarly, two 3' IVSs are excised before the polyadenylation step. These results suggest that IVS splicing is faster than eukaryotic genomic cis-splicing and involves components other than those of the classical spliceosomes.

The transient behavior of light emission has been known for a long time; the so called phosphorescence of many organic compounds or color centers in inorganic insulators can be easily observed by the naked eye for example. Many people have played with a clock whose needles and numbers are coated with a phosphor and remember the slow vanishing of the emitted light after they have illuminated the clock for a short time. By doing that they have performed a luminescence time resolved experiment and have verified that the luminescence lifetime of this particular phosphor is of the order of an hour. Some of them may have verified that this lifetime is the same for various excitation intensities or excitation times.