Antibiotic photocatalysis and antimicrobial activity of low-cost multifunctional Fe3O4@HAp nanocomposites

Water contamination by multiple pollutants is a serious environmental issue originating from the many diverse sources of pollution. It has worsened with the appearance of new contaminants, named emerging micropollutants, such as drug residues which are considered a potential threat to human health and/or ecosystems. These require prior treatment before release into the environment. Simultaneous adsorption and photocatalysis as well as solid-liquid separation are promising technologies for water treatment. In order to obtain low cost photoactive nanocomposites, porous and magnetic Fe3O4-hydroxyapatite (wFeHAp) nanocomposites were prepared by soft chemistry from the dissociation of natural phosphate into Ca2+ and H3PO4 precursors, further neutralized by ammonia in the presence of preformed Fe3O4 particles. The magnetic nanocomposites were characterized and examined as effective antibacterial agents. Fe3O4 association with apatite modifies the surface properties of the wFeHAp nanocomposite materials, yielding efficient antimicrobial activity for S. aureus, B. subtilis, E. coli and K. pneumoniae strains. The photocatalytic removal of ciprofloxacin (CPF) and oxytetracyclin (OXT) antibiotics in water was also evaluated. The wFeHAp nanocomposites adsorbed and degraded the selected antibiotics successfully. Toxicity evaluation of the treated water after photodegradation using the four strains demonstrates the absence of toxic by-products at the end of the reaction. Therefore, Fe3O4@HAp nanoparticles are valuable for antimicrobial and photocatalysis applications.

Evaluating Fire Performance of Glass-Polyurethane Composite for Sustainable Cladding via Numerical and Empirical Simulation

The increased demand for cladding in high-rise buildings has prompted engineers to explore alternative products utilizing recycled materials. However, ensuring fire compliance in these alternative claddings, which are predominantly composed of low-volume polymer-based composites, poses a critical challenge. Traditional experimental methods for fire evaluation are costly, time consuming, and environmentally impactful. Considering this, a numerical approach was proposed for evaluating the fire performance of glass-polymer composite materials, which contain a high proportion of recycled glass and a lower percentage of rigid polyurethane. A cone calorimeter test was simulated using Computational Fluid Dynamics (CFD) software to investigate the flammability of the novel glass-polymer composite material. This validated numerical model was employed to assess the combustibility of the glass-polyurethane composite materials and identify influential parameters using the Design of Experiments (DoE) method. Statistical analysis revealed that three material properties, namely, the heat of combustion, the absorption coefficient, and the heat of reaction, significantly influenced the peak heat release rate (pHRR) of the glass-polyurethane composite materials compared to other properties. Based on these findings, an empirical equation was proposed that demonstrates a reasonable correlation with the pHRR of low-polymer recycled glass composite materials. The outcomes of this study hold considerable importance for understanding and predicting the combustibility behaviour of low-polymer-glass composites. By providing a validated numerical model and identifying critical material properties, this research contributes to the development of sustainable fire safety solutions for buildings, enabling the use of recycled materials and reducing reliance on conventional claddings.

Application of coal fly ash in pavement subgrade stabilisation: A review

Expansive clays are found in many countries worldwide, and they exhibit inherent volume change during the seasonal moisture variation causing cracks, heaves, and damages to the overlying pavements. Chemical stabilisation is one of the most used approaches to treat the expansive clay subgrades. Cement, Lime and Fly ash are the most commonly used stabilisers, in which fly is cheaper and a by-product obtained from the coal power plant. This paper reviews fly ash stabilisation on various clay types, including low plasticity clays, high plasticity clays, silty clays, organic clays, and peats. The review begins with the properties of fly ash, followed by the characteristics of fly ash stabilised subgrades. The micro-level mechanism, physical, mechanical, and hydraulic characteristics of stabilised pavements are presented graphically for the Class C, and F fly ashes. The micro-level studies reveal that the pozzolanic reaction is stronger than the cation exchange during the fly ash stabilisation. The unconfined compressive strength (UCS), California bearing ratio (CBR) and resilient modulus (M_r) increased with the fly ash addition and curing time for most soft soils except peat clays. Based on the mechanical and hydraulic characteristics, using 15% class C fly ash with 7 days of curing is recommended for optimum performance. Although few research studies confirm that the leachate limit of stabilised soil is within the acceptable limit, further studies are required to investigate the uptake of heavy metals and other certain carcinogenic contaminants. This study will provide key information for researchers and Engineers on the selection of fly ash stabilisation measures for expansive subgrades.

Bumblebee hairs as electric and air motion sensors: theoretical analysis of an isolated hair

Foraging bumblebees are electrically charged. Charge accumulation has been proposed to enable their ability to detect and react to electrical cues. One mechanism suggested for bumblebee electro-sensing is the interaction between external electric fields and electric charges accumulating on fine hairs on the cuticular body. Such hairs exhibit several functional adaptations, for example, thermal insulation, pollen capture and notably, the sensing of air motion such as flow currents or low frequency sound particle velocity. Both air motion and electric fields are ubiquitous in the sensory ecology of terrestrial arthropods, raising the question as to whether cuticular hairs respond to both stimuli. Here, a model-theoretical approach is taken to investigate the capacity of bumblebee filiform hairs as electric sensors and compare it to their response to air motion. We find that oscillating air motion and electric fields generate different mechanical responses, depending on stimulus frequency and body geometry. Further, hair morphology can enhance one sensing mode over the other; specifically, higher surface area favours electric sensitivity. Assuming a maximum stable charge on the hair that is limited only by electric breakdown of air, it is expected that an applied oscillating electric field strength of approximately 300 V m⁻¹ produces comparable mechanical response on the hair as a 35 mm s⁻¹ air flow oscillating at 130 Hz—an air disturbance signal similar to that produced by wingbeats of insects within a few bodylengths of the bumblebee. This analysis reveals that bumblebee filiform hairs can operate as bi-modal sensors, responding to both oscillating electric and air motion stimuli in the context of ecologically relevant scenarios.

Conseils de bonnes pratiques pour les praticiens spécialisés en laryngologie et en phoniatrie en contexte d’épidémie COVID-19

Les gestes mettant le personnel soignant en contact étroit avec les voies aériennes sont particulièrement à risque de contamination par le virus SARS-Cov-2, en particulier en cas de crachats, toux, ou présence d’une trachéotomie. Dans la phase pandémique actuelle, tous les patients sont à considérer comme potentiellement infectés donc l’attitude du soignant est à adapter au statut COVID-19 du patient mais aussi et surtout au geste effectué. Ainsi, s’il s’agit d’un geste invasif comme une fibroscopie ou une pose de sonde naso-gastrique notamment, les précautions sont identiques pour tous les patients quel que soit leur statut COVID. Les rééducations vocales sont à considérer comme non urgentes dans ce contexte. Les recommandations présentées ici en date du 9 avril 2020 sont donc surtout destinées à la prise en charge des troubles de la déglutition (ceci pouvant parfois être dangereux pour le patient) ou d’une dysphonie récente inquiétante. Dès qu’elles sont possibles techniquement et réglementairement, les télé-consultations seront à privilégier. Seules les urgences non différables seront réalisées en présentiel et ce après décision collégiale (ou en fonction des informations venues des autorités de santé) et en prenant les précautions adéquates détaillées ici.

Guidelines of clinical practice for the management of swallowing disorders and recent dysphonia in the context of the COVID-19 pandemic

Procedures putting healthcare workers in close contact with the airway are particularly at risk of contamination by the SARS-Cov-2 virus, especially when exposed to sputum, coughing, or a tracheostomy. In the current pandemic phase, all patients should be considered as potentially infected. Thus, the level of precaution recommended for the caregivers depends more on the type of procedure than on the patient's proved or suspected COVID-19 status. Procedures that are particularly at high risk of contamination are clinical and flexible endoscopic pharyngo-laryngological evaluation, and probably also video fluoroscopic swallowing exams. Voice rehabilitation should not be considered urgent at this time. Therefore, recommendations presented here mainly concern the management of swallowing disorders, which can sometimes be dangerous for the patient, and recent dysphonia. In cases where they are considered possible and useful, teleconsultations should be preferred to face-to-face assessments or rehabilitation sessions. The latter must be maintained only in few selected situations, after team discussions or in accordance with the guidelines provided by health authorities.

Prevalence and characterisation of vocal fold motion impairment (VFMI) in patients with Multiple system atrophy compared with Parkinson's disease

INTRODUCTION

Multiple system atrophy (MSA) is a neurodegenerative disorder in which vocal fold mobility can be affected, sometimes leading to life-threatening situations. Our aim was to know if laryngeal examination could help differentiate MSA from Parkinson's disease (PD).

MATERIALS AND METHODS

Between 2004 to 2014, all consecutive patients diagnosed with probable MSA were included in this retrospective, monocentric study. Flexible laryngoscopy was obtained in 51 MSA patients and compared with 27 patients with Parkinson's disease (PD). Laryngeal muscles EMG was available in 6 MSA patients.

RESULTS

Vocal fold motion impairments (VFMI) was found in 35 (68.6%) MSA patients: 15 (29.4%) had uni- or bilateral vocal fold abnormal movement (VFAM), 13 (25.5%) had uni- or bilateral vocal fold abductor paresis (VFABP), 4 (7.8%) had uni- or bilateral vocal fold adductor paresis (VFADP), 10 (19.6%) had bilateral vocal fold paralysis (BVFP). VFMI was found in 13 PD patients (48.1%) all of whom had VFADP. Presence of BVFP was found associated with stridor (P<0.001) and dysphagia (P=0.002). In all muscles examined in 6 MSA patients, the EMG showed neuropathic patterns.

CONCLUSIONS

Our data support that VFMI may be encountered in two-thirds of MSA with a variable degree of gravity. Laryngological examination should be considered as a supplementary tool for the diagnosis and prognosis of MSA. VFMI in particular VFAM, VFABD and BVFP should be discussed as an additional possible red flag even at an early stage of MSA and could help discriminate MSA from PD.

A Randomised Trial of Subcutaneous Low Molecular Weight Heparin (CY 216) Compared with lntravenous Unfractionated Heparin in the Treatment of Deep Vein Thrombosis

The standard treatment of deep vein thrombosis is given by continuous intravenous infusion of unfractionated heparin. This entails hospitalisation, nursing care, immobility and repeated laboratory tests (e.g. activated partial thromboplastin time [APTT], platelet count). In addition approximately 10% of patients suffer major haemorrhages. The potential advantages of a low molecular weight heparin (CY 216) given subcutaneously were explored in a randomised trial with blind quantitative evaluation of venograms. The study included 166 patients and both “therapeutic efficacy” and “intention to-treat” analyses showed that subcutaneous CY 216 in fixed doses based only on body weight was more effective on the Arnesen and Marder phlebographic scores than continuous i. v. standard heparin with daily dose adjustment according to results of coagulation tests. There was no increase in the risks of pulmonary embolism, haemorrhage or clot extension.

Hepatic Cytolytic and Cholestatic Changes Related to a Change of Lipid Emulsions in Four Long-Term Parenteral Nutrition Patients With Short Bowel

Long-term parenteral nutrition hepatic-related impairment is commonly reported and diversely explained. However, with a low cyclic caloric intake (100% to 130% of basal metabolism calculated with the Harris-Benedict formula) consisting of two-thirds glucose, one-third lipid, and 0.20 to 0.25 g of nitrogen per kilogram per day, these complications were infrequent in a clinical practice of home long-term parenteral nutrition. Retrospectively, it was noticed that the switch from Intralipid 20% to Ivelip 20% at the same amount was followed within 2 months by four cases of jaundice in a population of four home long-term parenteral nutrition patients with short bowel disease. Hepatic disturbances were characterized by cytolysis and cholestasis and were reversible after switching from Ivelip 20% back to Intralipid 20%. Neither viral, nor biliary, nor septic etiologies were detected. The exact pathological mechanism remains unknown. The basal composition of both lipid emulsions seems to be identical: soy oil emulsion emulsified by egg phospholipids. However, some differences exist such as the size of particles, the presence of sodium oleate in Ivelip 20%, and the purification process of lecithin. These may explain the difference in hepatic tolerance during long-term parenteral nutrition.

A videofluoroscopic study comparing severe swallowing disorders in patients treated surgically or with radiation for oropharyngeal cancer

The aim of this study was to analyze the causal mechanisms of severe swallowing disorders after the treatment of oropharyngeal cancer. Twenty-six patients with severe swallowing disorders at ≥12 months after treatment for oropharyngeal cancer were analyzed retrospectively using videofluoroscopy. Fourteen patients (54%) had been treated with surgery (±postoperative radiotherapy), while 12 patients (46%) had been treated with (chemo)radiotherapy. Videofluoroscopy analysis showed a localized alteration in the surgical excision area resulting in impaired tongue root retraction in the surgical group (P=0.012), while general impairment of the pharyngeal, laryngeal, and upper oesophagus sphincter was found in the non-surgical group. Aspirations in the surgical group most often occurred after swallowing, while in the non-surgical group, they occurred during and after swallowing (P=0.039). This analysis by videofluoroscopy provides important insights into the mechanisms giving rise to swallowing disorders after the treatment of oropharyngeal cancer.

Resonant and antiresonant bouncing droplets

When placed onto a vibrating liquid bath, a droplet may adopt a permanent bouncing behavior, depending on both the forcing frequency and the forcing amplitude. The relationship between the droplet deformations and the bouncing mechanism is studied experimentally and theoretically through an asymmetric and dissipative bouncing spring model. Antiresonance phenomena are evidenced. Experiments and theoretical predictions show that both resonance at specific frequencies and antiresonance at Rayleigh frequencies play crucial roles in the bouncing mechanism. In particular, we show that they could be exploited for bouncing droplet size selection.

Non-invasive ventilation in the treatment of sleep-related breathing disorders: A review and update

Non-invasive mechanical ventilation (NIV) was originally used in patients with acute respiratory compromises or exacerbations of chronic respiratory diseases as an alternative to intubation. Over the last thirty years NIV has been used during the night in patients with stable chronic lung diseases such as obstructive sleep apnea, the overlap syndrome (COPD and obstructive sleep apnea), neuromuscular disorders, obesity-hypoventilation syndrome and in other conditions such as sleep disorders associated with congestive heart failure. In this review we discuss the different types of NIV, the specific conditions in which they can be used as well as the indications, recommendations, and evidence supporting the efficacy of NIV.

[F0 characteristics in Parkinsonian speech: Contrast between the effect of hypodopaminergy due to Parkinson's disease and that of the therapeutic delivery of L-Dopa]

Voice and speech impairments are frequent in Parkinson's disease, particularly when the disease is at an advanced stage. These impairments affect spoken communication and may become a serious disability for someone with Parkinson's disease. Many studies based on auditory-perceptual or acoustic methods have been carried out to characterize dysarthria. The heterogeneity of evaluation methods and experimental bias however make results difficult to understand. For instance, in terms of phonatory impairments and with regard to F0, results are contradictory: PD speech may be characterized by either higher F0 or lower F0 compared to control subjects, or there may be no difference at all between the two population. In this study, we aim to provide a conceptual and methodological framework which allows for interpreting the results obtained from 44 speakers (29 PD and 15 control subjects) in relation to physiological (gender, age, PD subjects' pharmacologic state) and linguistic (speech production tasks) constraints. For the present corpus, we did not observe any F0 mean difference between the two groups. Our results however reveal a significant increase in F0 mean in PD subjects under L-dopa. We assume a double and opposite effect on F0 mean during drug withdrawal: low sub-glottal pressure, due to PD, results in a decrease in F0, while laryngeal rigidity leads to an increase in F0. These two effects thus mutually annihilate. Under L-Dopa, however, the drug effect increases sub-glottal pressure, which combined with an increase in F0 due to rigidity, leads to a global increase in F0.

[Evaluation of the management of COPD exacerbations: an audit in French emergency services]

INTRODUCTION

Acute exacerbations of chronic obstructive pulmonary disease (COPD) patients are major events in the history of this chronic respiratory disease. Their management in French emergency services is unknown, although national guidelines exist.

METHODS

This is a descriptive audit study, over a 10 weeks period (12/01-22/03/2009), of the management of COPD exacerbations in the RESUVal (Réseau des Urgences de la Vallée du Rhône, France) network emergency departments.

RESULTS

The enrollement of 16 emergency units allowed the analysis of 221 exacerbations of COPD. Measurement of respiratory rate and description of the sputum were mentioned in only 99 (45%) medical records. The rest of the initial assessment was generally satisfactory. Regarding the therapeutic management, 215 (97%) patients received oxygen, beta-2-agonist aerosols were administrated for 209 (95%) patients and anticholinergic aerosols were used for 176 (80%) patients. A systemic corticosteroid and antibiotics were respectively prescribed for 116 (52%) and 123 (56%) patients. Non-invasive ventilation (NIV) was used in only 59% of patients presenting a pH<7.35.

CONCLUSIONS

These findings demonstrate that management of exacerbations of COPD could be improved through systematic patients' respiratory rate and sputum characteristics recording or NIV utilization reinforcement.

High-speed atomic force microscopy in slow motion--understanding cantilever behaviour at high scan velocities

Using scanning laser Doppler vibrometer we have identified sources of noise in contact mode high-speed atomic force microscope images and the cantilever dynamics that cause them. By analysing reconstructed animations of the entire cantilever passing over various surfaces, we identified higher eigenmode oscillations along the cantilever as the cause of the image artefacts. We demonstrate that these can be removed by monitoring the displacement rather than deflection of the tip of the cantilever. We compare deflection and displacement detection methods whilst imaging a calibration grid at high speed and show the significant advantage of imaging using displacement.

The next step in cicada audition: measuring pico-mechanics in the cicada's ear

Female cicadas use sound when they select a mate from a chorus of singing males. The cicada has a tympanal ear; and the tympanal membrane, and constituent tympanal ridge, act as both acousto-mechanical transducers and frequency filters. The tympanal ridge is physically connected to a large number of mechanoreceptor neurons via a cuticular extension known as the tympanal apodeme. Using microscanning laser Doppler vibrometry, we measured for the first time the in vivo vibrations of the apodeme of female Cicadatra atra in response to the motion of the tympanum driven by sound. These measurements reveal that the nanoscale motion of the tympanal membrane is over a magnitude greater than that of the apodeme. Furthermore, the apodeme acts as an additional mechanical frequency filter, enhancing that of the tympanal ridge, narrowing the frequency band of vibration at the mechanoreceptor neurons to that of the male calling song. This study enhances our understanding of the mechanical link between the external ear of the cicada and its sensory cells.

Mathematical modelling of the active hearing process in mosquitoes

Insects have evolved diverse and delicate morphological structures in order to capture the inherently low energy of a propagating sound wave. In mosquitoes, the capture of acoustic energy and its transduction into neuronal signals are assisted by the active mechanical participation of the scolopidia. We propose a simple microscopic mechanistic model of the active amplification in the mosquito species Toxorhynchites brevipalpis. The model is based on the description of the antenna as a forced-damped oscillator coupled to a set of active threads (ensembles of scolopidia) that provide an impulsive force when they twitch. This twitching is in turn controlled by channels that are opened and closed if the antennal oscillation reaches a critical amplitude. The model matches both qualitatively and quantitatively with recent experiments: spontaneous oscillations, nonlinear amplification, hysteresis, 2 : 1 resonances, frequency response and gain loss owing to hypoxia. The numerical simulations presented here also generate new hypotheses. In particular, the model seems to indicate that scolopidia located towards the tip of Johnston's organ are responsible for the entrainment of the other scolopidia and that they give the largest contribution to the mechanical amplification.

Hearing in tsetse flies? Morphology and mechanics of a putative auditory organ

Tympanal hearing organs are widely used by insects to detect sound pressure. Such ears are relatively uncommon in the order Diptera, having only been reported in two families thus far. This study describes the general anatomical organization and experimentally examines the mechanical resonant properties of an unusual membranous structure situated on the ventral prothorax of the tsetse fly, Glossina morsitans (Diptera: Glossinidae). Anatomically, the prosternal membrane is backed by an air filled chamber and attaches to a pair of sensory chordotonal organs. Mechanically, the membrane shows a broad resonance around 5.3-7.2 kHz. Unlike previously reported dipteran tympana, a directional response to sound was not found in G. morsitans. Collectively, the morphology, the resonant properties and acoustic sensitivity of the tsetse prothorax are consistent with those of the tympanal hearing organs in Ormia sp. and Emblemasoma sp. (Tachinidae and Sarcophagidae). The production of sound by several species of tsetse flies has been repeatedly documented. Yet, clear behavioural evidence for acoustic behaviour is sparse and inconclusive. Together with sound production, the presence of an ear-like structure raises the enticing possibility of auditory communication in tsetse flies and renews interest in the sensory biology of these medically important insects.

Time-resolved tympanal mechanics of the locust

A salient characteristic of most auditory systems is their capacity to analyse the frequency of sound. Little is known about how such analysis is performed across the diversity of auditory systems found in animals, and especially in insects. In locusts, frequency analysis is primarily mechanical, based on vibrational waves travelling across the tympanal membrane. Different acoustic frequencies generate travelling waves that direct vibrations to distinct tympanal locations, where distinct groups of correspondingly tuned mechanosensory neurons attach. Measuring the mechanical tympanal response, for the first time, to acoustic impulses in the time domain, nanometre-range vibrational waves are characterized with high spatial and temporal resolutions. Conventional Fourier analysis is also used to characterize the response in the frequency domain. Altogether these results show that travelling waves originate from a particular tympanal location and travel across the membrane to generate oscillations in the exact region where mechanosensory neurons attach. Notably, travelling waves are unidirectional; no strong back reflection or wave resonance could be observed across the membrane. These results constitute a key step in understanding tympanal mechanics in general, and in insects in particular, but also in our knowledge of the vibrational behaviour of anisotropic media.

A series of five adult cases of respiratory syncytial virus-related acute respiratory distress syndrome

Respiratory syncytial virus is a common cause of respiratory tract disease in children, predominantly presenting with mild symptoms. We present five cases of respiratory syncytial virus infection of the lower respiratory tract in immunocompromised adults suffering from severe respiratory insufficiency leading to bilateral pneumonia and fulfilling the criteria for acute respiratory distress syndrome. Respiratory syncytial virus was cultured as the only pathogen in the bronchoalveolar lavage fluid in four of these patients. Despite various therapeutic interventions, only one patient survived. Respiratory syncytial virus was implicated as a direct cause of respiratory failure. Respiratory syncytial virus may be an underestimated cause of severe respiratory failure and acute respiratory distress syndrome in the immunocompromised adult admitted to the intensive care unit.

Relationship between lignin structure and delignification degree in Pinus pinaster kraft pulps

This study examines the structure of residual and dissolved lignins from Pinus pinaster pulps obtained at different degrees of delignification by laboratory conventional kraft pulping. The cooking H factor was varied from 85 to 8049. The residual and dissolved lignin samples were characterised by elemental analysis, residual carbohydrate content, permanganate oxidation and 13C NMR spectroscopy. The reflectance factor of the pulps was also determined in order to tentatively correlate the delignification degree and residual lignin structure with the pulp colour. The obtained results confirmed that the delignification degree increases the condensation of the lignin structure, which might have an influence upon the observed increased pulp colour. The lack of selectivity of kraft pulping process in the case of more delignified pulps was also shown.

[Esophageal achalasia, sleep disorders and chorea in a tauopathy without ophthalmoplegia, parkinsonian syndrome, nor dementia (progressive supranuclear palsy?): clinicopathological study]

CONTEXT

Progressive supranuclear palsy (PSP) is classically characterized by supranuclear ophthalmoplegia, paroxysmal imbalance with backward falling, axial dystonia, rigidity, pseudobulbar palsy and cognitive dysfunction. However, incomplete or atypical clinical presentation has been previously reported, but in all these cases, the patients had at least one of the main clinical features of the disease (ophthalmoplegia, parkinsonian syndrome or cognitive dysfunction).

CASE REPORT

A 60-year-old woman presented with nocturnal agitation and choreiform movements. A few months later she developed severe swallowing disorders, caused by achalasia of the upper esophageal sphincter, and responsible for recurrent acute respiratory distress and pneumonia, prevailing to tracheotomy and gastrostomy. She died suddenly two years after the onset of the symptoms.

RESULTS

Postmortem examination of brain revealed a tauopathy, with deposition of abnormal phosphorylated tau in threads and in coiled-shaped as well as globose tangles in the brainstem, subthalamic nuclei and hippocampus. Nuclei of the medulla, including the vagus/solitarius complex and the region of the nucleus ambiguous were especially rich in tau positive inclusions. Ultrastructural analysis of globoid-shaped tangles in the brainstem revealed the presence of straight and paired helicoidal filaments compatible with a PSP.

CONCLUSIONS

This case contributes to improve knowledge of the clinical phenotypic range of PSP. In this case, the neuropathological lesions accounted for most of the symptoms. However, the early death of the patient was probably related to the particular distribution of the neuropathological lesions. This case suggests that the initial neuropathological changes in PSP is located in the dorsal brainstem.

Nanomechanical and electrical characterization of a new cellular electret sensor-actuator

Electrically charged cellular polymers are known to display pseudo-piezoelectric effects that endow them with interesting mechano-electrical characteristics. When a film of such a polymer is compressed, charge is generated across its thickness, and conversely, applying an oscillatory or static potential elicits mechanical motions. This dual sensor-actuator behaviour can be embedded in one material and presents distinct advantages of functional integration. A novel electroactive foam is presented here that embeds such a sensor-actuator function. The foam has a sensitivity constant (d(33)) of 330 pC N(-1). Interestingly, the resonant behaviour of the cellular film can be altered by variation in the DC offset across the material. Such adaptive capacity could be of great advantage for tuning polymer-based mechanical devices to be either efficient sound radiators and mechanical actuators, or sensitive and coherent sensors. Possible applications in microfluidics are also discussed.

Necrotizing gastritis due to Bacillus cereus in an immunocompromised patient

Bacillus cereus is increasingly being acknowledged as a serious bacterial pathogen in immunocompromised patients. We present a case of acute necrotizing gastritis caused by B. cereus in a 37-year-old woman with acute myeloblastic leukemia, who recovered following total parenteral nutrition and treatment with imipenem and vancomycin. B. cereus was isolated from gastric mucosa and blood cultures. Up to now, no case of acute necrotizing gastritis due to this organism has been reported.

Mechanics of a 'simple' ear: tympanal vibrations in noctuid moths

Anatomically, the ears of moths are considered to be among the simplest ears found in animals. Microscanning laser vibrometry was used to examine the surface vibrations of the entire tympanal region of the ears of the noctuid moths Agrotis exclamationis, Noctua pronuba, Xestia c-nigrum and Xestia triangulum. During stimulation with ultrasound at intensities known to activate receptor neurones, the tympanum vibrates with maximum deflection amplitudes at the location where the receptor cells attach. In the reportedly heterogeneous tympana of noctuid moths, this attachment site is an opaque zone that is surrounded by a transparent, thinner cuticular region. In response to sound pressure, this region moves relatively little compared with the opaque zone. Thus, the deflections of the moth tympanic membrane are not those of a simple circular drum. The acoustic sensitivity of the ear of N. pronuba, as measured on the attachment site, is 100+/-14 nm Pa(-1) (N=10), corresponding to tympanal motion of a mere 200 pm at sound pressure levels near the neural threshold.

The effect of landfill leachate composition on organics and nitrogen removal in an activated sludge system with bentonite additive

A pre-denitrification activated sludge system (AS) without internal recycle was used in lab-scale studies of landfill leachate treatment. A bentonite supplement at a ratio of 1:4 (mineral : biomass) was used to ensure high sludge settling levels and to serve as a micro-organisms carrier. The system was operated within different parameters such as hydraulic retention time (HRT), ammonia loading rate (ALR) or external recycle ratio, which was adapted to treat varying leachate concentrations of COD and ammonia, ranging from 1020 to 2680 mgO(2)l(-1) and 400-890 mgNH(4)-Nl(-1) respectively. The nitrification was complete and ammonia oxidation reached 99%; this was obtained while the ALR did not exceed 0.09 g NH(4)(+)-Ng(-1)MLVSS d(-1) and HRT was not lower than 1 day (in the aeration reactor). The performance of denitrification was successfully improved by controlling the external recycle rate, when the BOD(5)/N ratio in the raw leachate was 4.1. Consequently, N-removal of up to 80% was achieved. A 10-fold decrease in the denitrification rate was obtained at a BOD(5)/N ratio of 0.5. The efficiency of COD removal varied significantly from 36% to 84%. The positive effect of bentonite addition was determined and is discussed based on preliminary studies. The experiments were carried out in fill-and-draw activated sludge with bentonite; the biomass ratio was 1:2. The activated sludge with bentonite was fed with a synthetic high ammonia and organic-free medium.

Association d'une encéphalite à herpès virus 6 et d'un syndrome d'hypersensibilité médicamenteuse au triméthoprime-sulfaméthoxazole

INTRODUCTION

Human herpesvirus 6 (HHV-6), the causative agent of the common exanthem subitum, is a known cause of central nervous system infection in immunocompromised patients. It has been suggested that HHV-6 participate in the development of drug-induced hypersensitivity syndrome.

CASE REPORT

We reported a case of HHV-6 encephalitis associated with hypersensitivity syndrome induced by trimethoprim-sulfamethoxazole in a 72-year-old HIV-negative woman.

DISCUSSION

Our case confirmed that reactivation of HHV-6 infection may contribute to the development of the hypersensitivity syndrome.

Aspects cliniques, microbiologiques et thérapeutiques des infections à Nocardia sp. au centre hospitalier universitaire de Bordeaux entre 1993 et 2003

OBJECTIVE

Our goal was to describe the epidemiological, clinical, and microbiological characteristics of nocardiosis in the Bordeaux teaching hospital, between January 1, 1993 and December 31, 2003.

DESIGNS

The retrospective study included patients examined between January 1, 1993 and December 31, 2003 in whom a Nocardia bacterium had been identified from a biological sample.

RESULTS

Twenty-four out of 30 Nocardia sp. strains identified during the study period were classified as colonizing strains. 19 patients presented with risk factors for nocardiosis. Nocardia asteroïdes were found in 22 samples, mainly from pulmonary samples. 11 cases of infection due to Nocardia sp. were reported during the study period. Immunosuppression was reported in 7 cases. The clinical forms were not specific. The species incriminated belonged to the N. asteroïdes complex in 8 cases. Treatment consisted in a combination of 2 or 3 molecules including cotrimoxazole for an average duration of 9 months. 9 patients recovered.

CONCLUSIONS

The variability of clinical presentation and the lack of standard identification methods delayed the diagnostic. The treatment is not well defined. Clinical strains should be reported to the reference laboratory and prospective studies are necessary.

Évaluation des troubles de la parole et de la déglutition chez les patients atteints de sclérose latérale amyotrophique

Swallowing and speech disorders are the dramatic consequences of bulbar and pseudo-bulbar syndrome in ALS. Evaluation is necessary to guide speech therapy and to measure the effects of treatment. This article revues the different examinations used to assess bulbar and pseudobulbar involvement in an ALS patient: oromotor assessment, evaluation of the functions with self assessment, perceptive and objective evaluation of speech disorders, fiberoptic endoscopic evaluation of dysphagia (FEES) and videofluoroscopy.

Loading dose of vancomycin in critically ill patients: 15mg/kg is a better choice than 500mg

Delays in antimicrobial therapy in high-risk patients with infection may have deleterious effects on clinical outcomes. Therefore, appropriate treatment must be initiated promptly. The objective of this prospective study was to determine the better loading dose of vancomycin in critically ill patients with suspected Gram-positive infections. Two groups of patients were studied successively: Group A, loading dose of 500 mg; and Group B, loading dose of 15 mg/kg. The mean post-loading dose serum vancomycin concentration was significantly higher in Group B than in Group A (19.1 +/- 7.4 mg/L versus 10.4 +/- 2.7 mg/L; P < 0.001), without producing toxic peak levels. Clinical cure rates were significantly different for infected patients in Group B compared with Group A: 93% (14 of 15 patients) versus 56% (10 of 18 patients), respectively. However, the proportion of patients surviving to Intensive Care Unit discharge was similar. Because vancomycin is believed to achieve maximum killing at concentrations in serum of four to five times the minimum inhibitory concentration for the infecting organism, our results suggest that the 15 mg/kg loading dose should be preferred.

Leachate detoxification by combination of biological and TiO2-photocatalytic processes

Landfill leachates are a problematic wastewater due to their variable concentration, volume changing in time and presence of refractory and hazardous components. In this paper, the results of a new approach to photocatalysis assisted by biological process for the detoxification of stabilised landfill leachate are presented. The biologically pre-treated leachate still contained a significant amount of non-biodegradable COD and TOC amounting to 500 and 200 mg/L, respectively. The 300 min of photocatalytic treatment (UVC/TiO2) brought about a significant decrease in more than 80% refractory organics remaining in leachate. The effect of pH and catalyst loading on mineralisation, colour removal rate and biodegradability (BOD/COD) improvement in the photoreactor were discussed. The bio-accessibility of formed photocatalytic oxidation intermediates was confirmed by oxygen uptake rate (OUR) measurements. Consequently, a part of COD was successfully removed in post-biological treatment.