A magnetic shift register with out-of-plane magnetized layers

Using out-of-plane magnetized layers, a lateral shift register made from discrete elements is demonstrated. By carefully designing the in-plane shape of the elements which make up the shift register, both the position of nucleation of new domains and the coercivity of the element can be controlled. The dipole field from a neighboring element, placed tens of nanometers away, creates a bias field on the nucleation site, which can be used to create a NOT gate. By chaining these NOT gates together, a shift register can be created where data bits consisting of neighboring layers with aligned magnetization are propagated synchronously under a symmetric applied magnetic field. The operation of a 16 element shift register is shown, including field coupled data injection.

Protocol optimization of sacroiliac joint MR Imaging at 3 Tesla: Impact of coil design and motion resistant sequences on image quality

PURPOSE

To evaluate the impact of coil design and motion-resistant sequences on the quality of sacroiliac magnetic resonance imaging (MRI) examination in patients with spondyloarthropathy.

PATIENTS AND METHODS

One hundred and twenty-one patients with suspected sacroiliitis and referred for MRI of the sacroiliac joints were retrospectively evaluated with MRI at 3-Tesla. There were 78 women and 43 men with a mean age of 36.7±11.5 (SD) years (range: 15.8-78.4 years). Conventional and motion-resistant fat-saturated fast-spin echo T2-weighted sequences were performed with two different coils. Image quality was subjectively evaluated by two independent readers (R1 and R2) using a four-point scale. Confidence in the identification of bone marrow edema pattern (BMEP) was also evaluated subjectively using a three-point scale.

RESULTS

Phased array body coil yielded improved image quality compared to surface coil (14.1 to 30.4% for R1 and 14.6 to 25.7% for R2; P<0.0001). The impact of the sequence type on quality was also statistically significant (P=0.0046). BMEP was identified in 40 patients and best inter-reader agreement was obtained using the combination of phased-array body coil with motion-resistant T2-weighted sequence (kappa 0.990). The smallest number of indeterminate BMEP zones was seen on MRI set acquired with the phased-array body coil and motion-resistant T2-weighted sequence.

CONCLUSION

Phased array body coil and motion-resistant T2-weighted sequences perform better than surface coil and conventional T2-weighted sequences for the evaluation of sacroiliac joints, increasing confidence in the identification of BMEP.

Forward modelling the rubber hand: illusion of ownership modifies motor-sensory predictions by the brain

The question of how we attribute observed body parts as our own, and the consequences of this attribution on our sensory-motor processes, is fundamental to understand how our brain distinguishes between self and other. Previous studies have identified interactions between the illusion of ownership, and multi-sensory integration and cross-sensory predictions by the brain. Here we show that illusory ownership additionally modifies the motor-sensory predictions by the brain. In our preliminary experiments, we observed a new numbness illusion following the classical rubber-hand illusion (RHI); brushing only the rubber hand after induction of the RHI results in illusory numbness in one's real hand. Previous studies have shown that self-generated actions (like tickling) are attenuated by motor-sensory predictions by the so-called forward model. Motivated by this finding, here we examined whether the numbness illusion after the RHI is different when the rubber hand is brushed oneself, compared with when the brushing is performed by another. We observed that, all other conditions remaining the same, haptic perception in the real hand was lower (numbness higher) during self-generated brushing. Our result suggests that RHI reorganizes the forward model, such that we predict haptic consequences of self-generated motor actions on the rubber hand.

Trace element content in tea brewed in traditional metallic and stainless steel teapots

The migration of metals in tea brewed in metallic teapots was investigated. The teapots were obtained from North Africa stores in Brussels in 2005-2006 and in 2011. Chinese gunpowder green tea, the most commonly used tea in the Moroccan community, was used to prepare the tea. Tea brewed in metallic teapots was compared to tea brewed in a glass vessel in order to evaluate the contribution of the tea and the teapots to the metal concentrations in the brewed tea. Tea samples were also collected in Moroccan households and in tearooms in Brussels. The elements As, Cd, Pb, Sn, Mn, Fe, Cr, Co, Ni, Cr, Cu, Zn, and Al were analyzed by high-resolution sector field inductively coupled mass spectrometry. The relationship between the metal composition of the alloy of the teapot and the metal concentration in tea was also investigated. Migration of Pb and to a lesser amount Ni, Cu, and Zn was observed in brass teapots and migration of Cd from a number of stainless steel teapots was observed. The soldering connecting the sprout to the teapot was shown to be an important source of Pb to the tea. High levels of Mn and Al were also observed in the brewed tea and these elements where shown to originate from the tea itself. Metal exposure from tea drinking was calculated for different tea consumption levels and different metal concentration levels and compared to toxicological reference values.

Improvement of domain wall conduit properties in cobalt nanowires by global gallium irradiation

Applications based on the movement of domain walls (DWs) in magnetic nanowires (NWs) require a good DW conduit behavior, i.e. a significant difference between DW nucleation and propagation fields. In this work, we have systematically studied how this property evolves in cobalt NWs grown by focused electron beam induced deposition (FEBID) as a function of global gallium irradiation, for irradiation doses up to 1.24 × 10(17) ions cm(-2). Whereas for high doses the DW conduit is lost, below 6.42 × 10(15) ions cm(-2) the difference between the two fields increases with irradiation, becoming up to ∼9 times larger than for non-irradiated wires, due to a strong increase in the nucleation field, while the propagation field remains approximately constant. This behavior stems from two effects. The first effect is a decrease in the magnetic volume of the parasitic halo around the NW, typically present in FEBID nanostructures, leading to the disappearance of weak nucleation centers. The second effect is the formation of a 20 nm outer shell with Co crystals about twice the size of those forming the NW core, causing a net increase of the local magnetocrystalline anisotropy. The results presented here are important for the potential use of magnetic NWs grown by FEBID in DW-based devices, and might also be of interest for magnetic NWs fabricated by other techniques.

Spontaneous oral extrusion of an acrylic vertebral reconstruction 12 years after a vertebrectomy for a Ewing's sarcoma of the cervical spine: a case report

INTRODUCTION

Primary Ewing sarcoma of the cervical spine is rare, particularly in children population. The surgical management remains a challenge to associate the best oncological resection and to prevent spinal deformity. The situation is complicated owing to paucity of adapted instrumentation and their possible interactions with the growing bone.

CLINICAL PRESENTATION

We described the case of a young 19-year-old woman admitted for an oral extrusion of a bone polymethyl methacrylate (PMMA) allograft 12 years after a C4 circumferential vertebrectomy for primary Ewing's sarcoma. The vertebral anterior reconstruction was slowly repulsed by the growing spine giving way to an autologous bone without kyphosis deformation.

CONCLUSION

Bone reconstruction remains a challenge after extensive oncological resection particularly in cervical spine of children. Anterior and posterior instrumentation must be associated. The growing spine is not a good host for PMMA allograft and autograft seems to be preferred for anterior column fusion. In spite of the good oncological results, the authors raise the long-term issue of PMMA for vertebral reconstruction in young patients. With a long follow-up, they showed that posterior rigid fixation might prevent the cervical kyphosis.

Autologous bone flap versus hydroxyapatite prosthesis in first intention in secondary cranioplasty after decompressive craniectomy: a French medico-economical study

BACKGROUND AND PURPOSE

Decompressive craniectomy is the most common justification for cranioplasty. A medico-economial study based on the effective cost of the hydroxyapatite prosthesis, the percentage of autologous bone graft's loss due to bacterial contamination and the healthcare reimbursment, will allow us to define the best strategy in term of Healthcare economy management for the cranioplasties. A comparison was made between the two groups of patients, autologous bone flap versus custom-made prosthesis in first intention, based on the clinical experience of our department of neurosurgery.

RESULTS

No differences was shown between the two groups of patients, in terms of lenght of in-hospital stay and population's characteristics or medical codification. The mean cost of a cranioplasty using the autologous bone graft in first intention was €4045, while the use of hydroxyapatite prosthesis led to a cost of €8000 per cranioplasty.

CONCLUSION

In term of Healthcare expenses, autologous bone flap should be used in first intention for cranioplasties, unless the flap is contaminated or in specific indications, when the 3D custom-made hydroxyapatite prosthesis should be privilegied.

Domain wall interactions at a cross-shaped vertex

The interaction of two domain walls (DWs) at a cross-shaped vertex fabricated from two ferromagnetic nanowires has been experimentally investigated. Both magnetostatically repulsive and attractive interactions have been probed. It is found that in the repulsive case, a passing DW may directly induce the depinning of another that is already pinned at a vertex. This effect can be qualitatively described by considering only simple, magnetostatic-charge-based arguments. In the attractive case, however, asymmetric pinning is found, with complete suppression of depinning possible. This observed effect is contrary to simple charge-based arguments and highlights the need for full micromagnetic characterization of the DW interactions in more complex systems.

Dynamic oscillations of coupled domain walls

In domain wall (DW) excitation experiments, nonlinearity (NL) intrinsic to the DW dynamics is often hard to distinguish from perturbation due to the confining potential or DW distortion. Here we numerically investigate the dynamic oscillations of magnetostatically coupled DWs: a system well understood in the quasistatic limit. NL is observed, even for a harmonic potential, due to the intrinsic DW motion. This behavior is principally dependent on terms normally associated with the DW canonical momentum and is in contrast with a NL restoring potential. This NL is not observable in quasistatic measurements, relatively insensitive to the confining potential, and may be tuned by the nanowire parameters. The shown NLs are present in any DW restoring potential and must be accounted for when probing DW potential landscapes.

Dynamic propagation and nucleation in domain wall nanowire devices

The dynamic injection and propagation of domain walls (DWs) in technologically relevant geometries have been investigated. On short (~10 ns) timescales nucleation of a DW by a localized Oersted field is found to be well described using a Néel-Brown reversal mode. Using locally injected DWs, we test the propagation of DWs over long distances (~100 µm) in close proximity nanowires and beyond the Walker breakdown limit. In nanowires that act as true conduits to a DW, data can be successfully propagated without loss or inter-wire cross-talk. This is in contrast to poorly characterized systems where the DW is found to propagate asynchronously above the critical breakdown field.

An unusual and spectacular case of spindle cell lipoma of the posterior neck invading the spinal cervical canal and posterior cranial fossa

The authors describe the first case of spindle cell lipoma of the posterior neck invading the upper cervical spinal canal and the posterior cranial fossa. Spindle cell lipoma is an extremely rare variant of benign lipoma. It usually occurs as a solitary subcutaneous well-circumscribed lesion in the posterior neck or shoulders of adult men. Local aggressiveness is unusual. This 61-year-old man presented with an increased left cerebellar syndrome and headaches. He also had a posterior neck tumefaction, which had been known about for a long time. Computed tomography and MR imaging studies revealed a voluminous mass extending to the upper cervical canal and posterior cranial fossa and eroding the neighboring bones. The lesion was well delimited, and contrast enhancement was intense and heterogeneous. The tumor, which had initially developed under the muscles of the posterior neck, was totally resected. Histological assessment revealed numerous fat cells with spindle cells secreting collagen. The large size of the tumor and the submuscular location, bone erosion, and compression of the CNS were unusual in this rare subtype of benign adipose tumor. Its presentation could simulate a sarcoma.

Tunable remote pinning of domain walls in magnetic nanowires

Domain wall (DW) pinning in ferromagnetic nanowires is in general a complex process. Distortions of the DW shape make quantitative agreement between modeling and experiment difficult. Here we demonstrate pinning using nanometer scale localized stray fields. This type of interaction gives well-characterized, tailorable potential landscapes that do not appreciably distort the DW. Our experimental results are in excellent quantitative agreement with an Arrhenius-Néel model of depinning--a result only possible when the modeled potential profile agrees fully with that experienced by the DW.

Fast domain wall motion in magnetic comb structures

Modern fabrication technology has enabled the study of submicron ferromagnetic strips with a particularly simple domain structure, allowing single, well-defined domain walls to be isolated and characterized. However, these domain walls have complex field-driven dynamics. The wall velocity initially increases with field, but above a certain threshold the domain wall abruptly slows down, accompanied by periodic transformations of the domain wall structure. This behaviour is potentially detrimental to the speed and proper functioning of proposed domain-wall-based devices, and although methods for suppression of the breakdown have been demonstrated in simulations, a convincing experimental demonstration is lacking. Here, we show experimentally that a series of cross-shaped traps acts to prevent transformations of the domain wall structure and increase the domain wall velocity by a factor of four compared to the maximum velocity on a plain strip. Our results suggest a route to faster and more reliable domain wall devices for memory, logic and sensing.

Magnetization reversal in individual cobalt micro- and nanowires grown by focused-electron-beam-induced-deposition

We systematically study individual micro- and nanometric polycrystalline cobalt wires grown by focused-electron-beam-induced-deposition. The deposits were grown in a range of aspect ratios varying from 1 up to 26. The minimum lateral dimension of the nanowires was 150 nm, for a thickness of 40 nm. Atomic force microscopy images show beam-current-dependent profiles, associated with different regimes of deposition. The magnetization reversal of individual nanowires is studied by means of the spatially resolved magneto-optical Kerr effect. Abrupt switching is observed, with a systematic dependence on the wire's dimensions. This dependence of the coercive field is understood in magnetostatic terms, and agrees well with previous results on cobalt wires grown with different techniques. The influence of compositional gradients along the structural profile on the magnetic reversal is studied by using micromagnetic simulations. This work demonstrates the feasibility of using this technique to fabricate highly pure magnetic nanostructures, and highlights the advantages and disadvantages of the technique with respect to more conventional ones.

Near-field interaction between domain walls in adjacent Permalloy nanowires

The magnetostatic interaction between two oppositely charged transverse domain walls (TDWs) in adjacent Permalloy nanowires is experimentally demonstrated. The dependence of the pinning strength on wire separation is investigated for distances between 13 and 125 nm. The results can be described fully by considering the distribution of magnetic charge within rigid, isolated TDWs. Alternative DW internal structure cannot reproduce this observed dependence. Modeling suggests the TDW internal structure is not appreciably disturbed, and remains rigid although the pinning strength is significant.

Measuring domain wall fidelity lengths using a chirality filter

The motion of transverse domain walls (DWs) in thin Permalloy nanowires has been studied by locally detecting the chirality of the moving DW, using a cross-shaped trap acting as a chirality filter. We find that structural changes of the DW occur over a characteristic minimum distance: the "DW fidelity length." The measured field dependence of the fidelity length is in good qualitative agreement with a 1D analytical model and with published results of numerical simulations and experiments. We also demonstrate extension of the fidelity length to meter length scales using a series of filters.

Neurobiology of sleep disturbances in neurodegenerative disorders

This review presents sleep disturbances and their underlying pathophysiology in three categories of neurodegenerative disorders namely tauopathies, synucleinopathies, and Huntington's disease (HD) and prion-related diseases. Sleep abnormalities are a major and early feature of neurodegenerative disorders, especially for synucleinopathies, HD and prion-related diseases, in which the sleep-related brainstem regions are severely altered and impaired sooner than in most of the tauopathies. In synucleinopathies, HD and prion-related diseases, specific sleep disturbances, different from those observed in tauopathies, are considered as core manifestations of the disease and in some cases, as preclinical signs. For this reason, the evaluation of sleep components in these neurodegenerative disorders may be useful to make a diagnosis and to assess the efficacy of pharmacotherapy. Since sleep disruption may occur early in the course of neurodegeneration, sleep disturbance may serve as groundwork to study the efficacy of neuroprotective agents to prevent or delay the development of a full-blown neurodegenerative disorder. The cause of sleep disturbances in neurodegenerative disorders may be attributed to several factors, including age-related modifications, symptoms of the disease, comorbid conditions and the neurodegenerative process itself.

Age-at-onset in restless legs syndrome: a clinical and polysomnographic study

OBJECTIVE

To determine the distribution of age-at-onset in a large cohort of patients with restless legs syndrome (RLS) and to compare clinical and polysomnographic characteristics of patients with early and late age-at-onset of RLS.

METHODS

Two hundred and fifty patients with RLS were studied. Information on age-at-onset, etiology, familial history and symptoms severity of RLS was obtained. Age-at-onset density functions were determined from bootstrap methods and kernel density estimators.

RESULTS

Age-at-onset showed a significant bimodal distribution with a large peak occurring at 20 years of age and a smaller peak in the mid-40s. Early- and late-onset RLS could be separated with a cut-off at 36 years of age. Distributions of age-at-onset differed as a function of presence/absence of a familial history and etiology of RLS. Age-at-onset clearly differentiated patients with a primary RLS (early onset) from those with secondary RLS. Finally, early-onset RLS was associated with increased RLS severity with higher indices of periodic leg movements in sleep (PLMS) associated with microarousals and periodic leg movements during wakefulness (PLMW).

CONCLUSIONS

Early- and late-onset RLS could be distinguished depending on familial history and etiology of RLS. Our data suggest that different pathological processes are involved in these two groups, the early-onset group being highly genetically determined.

Effects of obstructive sleep apnea on cognitive function: a comparison between younger and older OSAS patients

BACKGROUND AND PURPOSE

Patients with obstructive sleep apnea syndrome (OSAS) present cognitive deficits similar to those observed with aging. The aim of the study was to assess the effects of age on cognitive functions in OSAS patients. It was hypothesized that older OSAS patients will exhibit significant cognitive dysfunction relative to younger OSAS patients and controls.

PATIENTS AND METHODS

Younger and older OSAS patients were compared to younger and older control subjects (age cut-off set at 50 yrs). Participants underwent a polysomnographic (PSG) and neuropsychological evaluation. Variables were analyzed by two-way analyses of variance (ANOVAs) with two factors: Group (control and OSAS) and Age (younger and older). Additionally, we evaluated the contribution of attentional deficits to cognitive dysfunction for each subgroup of patients by using Spearman correlation coefficients.

RESULTS

No Group-by-Age interaction was found for any neuropsychological variables (p<0.05). However, main Group and Age effects were found. Correlations indicated that attentional deficits contributed importantly to a poorer cognitive performance in younger OSAS patients only (p<0.01).

CONCLUSIONS

Our results are in agreement with those of the literature for both OSAS-related and aging-related cognitive deficits but did not demonstrate that age interacts with the effects of the OSAS condition to make those cognitive deficits worse.

Zinc and cadmium accumulation among and within populations of the pseudometalophytic species Arrhenatherum elatius: implications for phytoextraction

The purpose of this study was to investigate, under standard conditions, the bioaccumulation of zinc and cadmium in Arrhenatherum elatius, a perennial grass with a high biomass production. Nine populations of three different origins were tested: three metallicolous populations (mpop); three non-metallicolous populations (nmpop) and three populations developing on soils moderately metal polluted (medpop). We have found that bioaccumulation differs among these populations, with nmpop accumulating significantly more zinc (p<0.0001) and cadmium (p<0.0001) than mpop. Indeed, we have observed a concentration of 325 mg kg(-1) of zinc and 52 mg kg(-1) of cadmium in A. elatius shoots from mpop, whereas in nmpop, the concentration reached on average 524 mg kg(-1) zinc and 83 mg kg(-1) cadmium. In the same way, medpop accumulated as much zinc but more cadmium than nmpop. Moreover, the standard deviation of medpop was larger than the one for mpop and nmpop. Indeed, some A. elatius samples from medpop presented a high metal content whereas, others presented low concentrations in their shoots (ranging from 60 to 210 mg kg(-1) cadmium). Hence, these medpop exhibited a large variability among and within populations in accumulating zinc and cadmium in their shoots. Based on these results, the possibility of selecting A. elatius plants with the best accumulating capacity from medpop was proposed. We concluded that if the accumulation capacity is genetically controlled in A. elatius, this species fulfils this necessary condition for efficiently increasing species bioaccumulation by crossbreeding A. elatius plants with the higher accumulation capacity.

Long-term treatment with pramipexole in restless legs syndrome

The aim of the present study was to look at the long-term efficacy and side effects profiles of pramipexole in a large cohort of drug naïve patients with regard to dopaminergic medications. In all, 195 consecutive restless legs syndrome (RLS) patients who were prescribed pramipexole more than 1 year previously, agreed to undergo a telephone interview to assess both the efficacy and side effects of pramipexole. Forty-three patients had discontinued pramipexole: 20 because of side effects, six because of a lack of efficacy, six for both and 11 for other reasons. Patients who continued pramipexole for more than 1 year (n = 152) reported a mean decrease in RLS symptoms severity of 80.9% (SD = 19.6%). At the onset of treatment, the most common side effects were nausea (30%), tiredness (9%), dizziness (8%), headache (4%), insomnia (3%), dry mouth (2%), difficulty to concentrate (1.3%) and sleepiness (0.7%), At 30 months, most patients (n = 124/152; 81.6%) reported an absence of side effects of pramipexole. None of the adverse effects occurred in more than 5% of patients at follow-up. The present study confirms, in a large cohort of unselected patients, that pramipexole is effective and safe in the long-term treatment of RLS.

Increase of Fas-induced apoptosis by inhibition of extracellular phosphorylation of Fas receptor in Jurkat cell line

Apoptosis signalling through the Fas pathway requires several steps of aggregation of the Fas receptor in the membrane, including aggregation that may occur in the absence of Fas ligand. Association of Fas domains is determinant to signal transmission following Fas ligand binding to a specific domain. The domains involved in Fas aggregation are located in its extracellular region and contain three potential protein kinase C-binding motifs. We therefore studied the possibility that phosphorylation of the extracellular region of Fas might be implicated in the regulation of Fas-mediated apoptosis. Inhibition experiments of extracellular phosphorylation were performed in human Jurkat T leukemia cells with K252b, an impermeant protein-kinase inhibitor. Extracellular phosphorylation of Fas receptor was related to ecto-kinase, as assessed by the [gamma-(32)P] ATP labelling of Fas-116 kDa aggregates, suppressed by K252b inhibitor which significantly increased the sensitivity to Fas-mediated apoptosis. Ecto-PKC involvement was demonstrated by bisindolylmaleimide VIII, a selective inhibitor of protein kinase C which significantly increased both Fas aggregation in the membrane and Fas-mediated apoptosis and by the addition of the PKC pseudo-substrate 19-36 which inhibited the phosphorylation of 116 kDa Fas aggregates. These data support a role for Fas phosphorylation in the decreased sensitivity to apoptosis in the Jurkat T leukemia cell line.

Microstructure evolution of hydrated cement pastes

We propose an original method based on both proton nuclear magnetic relaxation dispersion and high-resolution NMR spectra to investigate the microstructure of synthesized Ca3SiO5-hydrated cement paste. This method allows a clear assessment of the local proton chemical sites as well as the determination of dynamical information of moving proton species in pores. We show also how the microstructure evolves during and after completion of hydration in a range of length scales between 2 and 500 nm. In particular, we show how the pore size distribution of the cement paste reaches progressively a power-law characteristic of a surface-fractal distribution with a dimension Df = 2.6, which takes into account the hierarchical order in the material. Last, we study how this pore size distribution is modified during setting by varying either the water-to-cement ratio or addition of ultrafine particles. This shows that our method could be relevant to relate the mechanical properties to the microstructure of the material. This proposed NMR method is general enough for the characterization of microstructure of any porous media with reactive surface involving water confinement.

Magnetic Domain-Wall Logic

"Spintronics," in which both the spin and charge of electrons are used for logic and memory operations, promises an alternate route to traditional semiconductor electronics. A complete logic architecture can be constructed, which uses planar magnetic wires that are less than a micrometer in width. Logical NOT, logical AND, signal fan-out, and signal cross-over elements each have a simple geometric design, and they can be integrated together into one circuit. An additional element for data input allows information to be written to domain-wall logic circuits.

Rapid reversal of global left ventricular dysfunction after accidental injection of 0.75 mg epinephrine in a 20-year-old patient

We report an accidental injection of epinephrine before spinal anaesthesia in a 20-year-old patient who subsequently developed immediate myocardial ischemia and global left ventricular dysfunction (ejection fraction of 20%). Hemodynamic status dramatically improved after nitroglycerin, calcium antagonists, acetyl salicylic acid and unfractionated heparin injections. Over 24 h, patient's ejection fraction fully recovered without kinetic abnormality.

Comparison of first-line antiretroviral therapy with regimens including nevirapine, efavirenz, or both drugs, plus stavudine and lamivudine: a randomised open-label trial, the 2NN Study

BACKGROUND

The 2NN Study was a randomised comparison of the non-nucleoside reverse-transcriptase inhibitors (NNRTI) nevirapine and efavirenz.

METHODS

In this multicentre, open-label, randomised trial, 1216 antiretroviral-therapy-naive patients were assigned nevirapine 400 mg once daily, nevirapine 200 mg twice daily, efavirenz 600 mg once daily, or nevirapine (400 mg) and efavirenz (800 mg) once daily, plus stavudine and lamivudine, for 48 weeks. The primary endpoint was the proportion of patients with treatment failure (less than 1 log(10) decline in plasma HIV-1 RNA in the first 12 weeks or two consecutive measurements of more than 50 copies per mL from week 24 onwards, disease progression [new Centers for Disease Control and Prevention grade C event or death], or change of allocated treatment). Analyses were by intention to treat.

FINDINGS

Treatment failure occurred in 96 (43.6%) of 220 patients assigned nevirapine once daily, 169 (43.7%) of 387 assigned nevirapine twice daily, 151 (37.8%) of 400 assigned efavirenz, and 111 (53.1%) of 209 assigned nevirapine plus efavirenz. The difference between nevirapine twice daily and efavirenz was 5.9% (95% CI -0.9 to 12.8). There were no significant differences among the study groups in the proportions with plasma HIV-1 RNA concentrations below 50 copies per mL at week 48 (p=0.193) or the increases in CD4-positive cells (p=0.800). Nevirapine plus efavirenz was associated with the highest frequency of clinical adverse events, and nevirapine once daily with significantly more hepatobiliary laboratory toxicities than efavirenz. Of 25 observed deaths, two were attributed to nevirapine.

INTERPRETATION

Antiretroviral therapy with nevirapine or efavirenz showed similar efficacy, so triple-drug regimens with either NNRTI are valid for first-line treatment. There are, however, differences in safety profiles. Combination of nevirapine and efavirenz did not improve efficacy but caused more adverse events.

Association between waking EEG slowing and REM sleep behavior disorder in PD without dementia

OBJECTIVE

To compare nondemented patients with Parkinson's disease (PD) with and without REM sleep behavior disorder (RBD) to healthy controls on quantitative EEG characteristics for both wakefulness and REM sleep.

METHODS

Fifteen patients with PD (7 patients with polysomnographic-confirmed RBD [PD-RBD] and 8 patients without RBD [PD-NRBD]) and 15 healthy control subjects were studied. Each subject underwent a quantitative EEG analysis of both wakefulness and REM sleep.

RESULTS

During wakefulness, patients with PD-RBD showed a higher theta power in frontal, parietal, temporal, and occipital regions in comparison to patients with PD-NRBD and control subjects. Moreover, a slowing of the dominant occipital frequency was observed only in patients with PD-RBD (p < 0.02). Patients with PD-NRBD did not present any slowing of the EEG. No between-group difference in quantitative REM sleep EEG was observed.

CONCLUSIONS

This study demonstrates that the EEG slowing reported during wakefulness in nondemented patients with PD is strongly related to the presence of RBD.

Slow dynamics of embedded fluid in mesoscopic confining systems as probed by NMR relaxometry

Mesoscopic media such as porous materials or colloidal dispersions strongly influence the dynamics of the embedded fluid. In the strong-adsorption regime, it was recently proposed that the effective surface diffusion on flat surface is anomalous and exhibits long-time pathology, enlarging the time domain of the embedded-fluid dynamics towards the low-frequency regime. An interesting way to probe such a slow interfacial process is to use the field-cycling NMR relaxometry. This technique is used here to probe the fluid dynamics in two types of interfacial systems: i) a colloidal glass made of thin and flat particles; ii) a fully saturated porous media, the Vycor glass. Experimental results are critically compared to either a simple theoretical model of NMR dispersion involving elementary steps of the fluid dynamics near an interface (loops, trains, tails) or Brownian-dynamics simulations performed inside 3D reconstructions of these confined systems.

What is the surface specific area of porous cement-based material? A nuclear magnetic relaxation dispersion approach

We propose a new NMR method to measure and follow the evolution of the surface specific area, Sp, of a porous cement-based material. This method, that does not require any preliminary drying process, uses nuclear magnetic relaxation dispersion (NMRD), the measurement of spin-lattice relaxation rate as a function of magnetic field strength or nuclear Larmor frequency. The method is applied for three different mortars samples prepared by mixing cement, sand, silica fume, water and superplasticizer with a water to cement ratio w/c=0.25, 0.38 and 0.65, respectively. The evolution of Sp grows linearly with the degree of advancement of chemical reactions measured by thermal heating and we evidence two relaxation processes independent of the w/c ratio.

Micropore size analysis by NMR in hydrated cement

The understanding of the microstructure of cement remains incomplete. Especially, the progressive setting of the material is still unclear. Micropore size distribution (microstructure) has been investigated by both standard proton nuclear magnetic relaxation (1H-NMR) and field-cycling relaxation in C3S hydrated paste. The non-exponential decay was interpreted as a distribution of discrete relaxation rates. The attribution of T1 is supported by both a spectral and a dispersion curve analyses. These experiments allow us to follow the structuration of the material during setting.

Probing the surface area of a cement-based material by nuclear magnetic relaxation dispersion

We show how nuclear magnetic spin-lattice relaxation dispersion of 1H water can provide a direct reliable value of the specific surface area of a cement-based material. The remarkable features of the relaxation dispersion support an interpretation in terms of coupled solid-liquid relaxation at pore interfaces, surface diffusion, and nuclear paramagnetic relaxation. The measurement is sufficiently fast to be applied continuously during the progressive hydration and setting of the material. This method is relevant to other chemically reactive porous media in chemical engineering and oil recovery.

[Brainstem anesthesia after peribulbar anesthesia]

We report a case of pupilloplasty under peribulbar anaesthesia complicated by a brainstem anaesthesia requiring tracheal intubation and mechanical ventilation. Immediate outcome was good. We discuss the different mechanisms of this complication. The subarachnoidal (intrathecal) injection of local anaesthesic seems to be the most probable cause. The use of short needles should theoretically decrease the risk. Despite all these precautions, peribulbar anaesthesia should not be considered as an ordinary procedure.

REM sleep behavior disorder and REM sleep without atonia in Parkinson's disease

OBJECTIVE

To determine the frequency of REM sleep behavior disorder (RBD) among patients with PD using both history and polysomnography (PSG) recordings and to further study REM sleep muscle atonia in PD.

BACKGROUND

The reported occurrence of RBD in PD varies from 15 to 47%. However, no study has estimated the frequency of RBD using PSG recordings or analyzed in detail the characteristics of REM sleep muscle atonia in a large group of unselected patients with PD.

METHODS

Consecutive patients with PD (n = 33) and healthy control subjects (n = 16) were studied. Each subject underwent a structured clinical interview and PSG recording. REM sleep was scored using a method that allows the scoring of REM sleep without atonia.

RESULTS

One third of patients with PD met the diagnostic criteria of RBD based on PSG recordings. Only one half of these cases would have been detected by history. Nineteen (58%) of 33 patients with PD but only 1 of 16 control subjects had REM sleep without atonia. Of these 19 patients with PD, 8 (42%) did not present with behavioral manifestations of RBD, and their cases may represent preclinical forms of RBD associated with PD. Moreover, the percentage of time spent with muscle atonia during REM sleep was lower among patients with PD than among healthy control subjects (60.1% vs 93.2%; p = 0.003).

CONCLUSIONS

RBD and REM sleep without atonia are frequent in PD as shown by PSG recordings.

Sleep disturbances and eeg slowing in alzheimer's disease

Changes in sleep structure, and especially REM sleep, and in EEG activation were studied in relation to the cholinergic deficit found in Alzheimer's Disease (AD). With respect to sleep architecture, only REM sleep percent was reduced in AD patients compared to controls as a result of a decrease in mean REM episode duration. Different results were obtained in patients with progressive supranuclear palsy (PSP). These results are discussed with respect to the role of brainstem and forebrain cholinergic populations in REM sleep generation in humans. More importantly, it was shown by means of spectral analyses that EEG slowing is much more prominent in REM sleep than in wakefulness in AD. Furthermore, there is a distinct topographical pattern of REM sleep EEG slowing in AD patients which is in agreement with findings from neuroradiological and neuropathological studies. Using the ratio of slow over fast frequencies from the temporal regions, a correct classification of 90.4% of subjects was obtained for the REM sleep EEG. This discrimination rate is the best marker of AD so far using a single measure. Quantitative REM sleep EEG was also used to evaluate patients' biological response to cholinergic treatments. Finally, we present here preliminary data on the progression of EEG slowing in wakefulness and in REM sleep. After six months on a placebo, there was only a decrease in alpha activity in wakefulness over all regions studied. No changes were observed for REM sleep.