Kinetic study of hydrogen lateral diffusion at high temperature in a directly-bonded InP-SiO2/Si substrate.

Hybrid integration of III-V materials onto silicon by direct bonding technique is a mature and promising approaches to develop advanced photonic integrated devices into the silicon photonics platform. In this approach, the III-V material stack is grown on an InP wafer in a unique epitaxial step prior to the direct bonding process onto the silicon-on-insulator wafer. Currently, no additional epitaxial regrowth steps are implemented after bonding. This can be seen as a huge limitation as compared to the III-V on III-V wafer mature technology where multi-regrowth steps are most often implemented. In this work, we have studied the material behavior of an InP membrane on silicon (InPoSi) under epitaxial regrowth conditions by metal-organic vapor phase epitaxy (MOVPE). MOVPE requires high-temperature elevation, typically above 600 °C. We show for the first time the appearance of voids at 400 °C in an InP seed (100 nm) directly-bonded onto a thermally oxidized Si substrate despite the use of a thick SiO2 oxide (200 nm) at the bonding interface. This phenomenon is explained by a weakening of the bonding interface while high-pressurized hydrogen is present. A kinetic study of the hydrogen lateral diffusion is carried out, enabling the assessment of its lateral diffusion length. To overcome the void formation, highly efficient outgassing trenches after bonding are demonstrated. Finally, high-quality AlGaInAs-based multi-quantum well (MQW) heterostructure surrounded by two InP layers was grown by MOVPE on InPoSi template patterned with outgassing trenches. This process is not only compatible with MOVPE regrowth conditions (650 °C under PH3) but also with conventional fabrication processes used for photonic devices.

Modification of translation factor aIF5A from Sulfolobus solfataricus.

Eukaryotic eIF5A and its bacterial orthologue EF-P are translation elongation factors whose task is to rescue ribosomes from stalling during the synthesis of proteins bearing particular sequences such as polyproline stretches. Both proteins are characterized by unique post-translational modifications, hypusination and lysinylation, respectively, which are essential for their function. An orthologue is present in all Archaea but its function is poorly understood. Here, we show that aIF5A of the crenarchaeum Sulfolobus solfataricus is hypusinated and forms a stable complex with deoxyhypusine synthase, the first enzyme of the hypusination pathway. The recombinant enzyme is able to modify its substrate in vitro resulting in deoxyhypusinated aIF5A. Moreover, with the aim to identify the enzyme involved in the second modification step, i.e. hypusination, a set of proteins interacting with aIF5A was identified.

Bronchodilator activity of (3R)-3-[[[(3-fluorophenyl)[(3,4,5-trifluorophenyl)methyl]amino] carbonyl]oxy]-1-[2-oxo-2-(2-thienyl)ethyl]-1-azoniabicyclo[2.2.2]octane bromide (CHF5407), a potent, long-acting, and selective muscarinic M3 receptor antagonist.

The novel quaternary ammonium salt (3R)-3-[[[(3-fluorophenyl)[(3,4,5-trifluorophenyl)methyl]amino]carbonyl]oxy]-1-[2-oxo-2-(2-thienyl)ethyl]-1-azoniabicyclo[2.2.2]octane bromide (CHF5407) showed subnanomolar affinities for human muscarinic M1 (hM1), M2 (hM2), and M3 (hM3) receptors and dissociated very slowly from hM3 receptors (t(½) = 166 min) with a large part of the receptorial complex (54%) remaining undissociated at 32 h from radioligand washout. In contrast, [(3)H]CHF5407 dissociated quickly from hM2 receptors (t(½) = 31 min), whereas [(3)H]tiotropium dissociated slowly from both hM3 (t(½) = 163 min) and hM2 receptor (t(½) = 297 min). In the guinea pig isolated trachea and human isolated bronchus, CHF5407 produced a potent (pIC(50) = 9.0-9.6) and long-lasting (up to 24 h) inhibition of M3 receptor-mediated contractile responses to carbachol. In the guinea pig electrically driven left atrium, the M2 receptor-mediated inhibitory response to carbachol was recovered more quickly in CHF5407-pretreated than in tiotropium-pretreated preparations. CHF5407, administered intratracheally to anesthetized guinea pigs, potently inhibited acetylcholine (Ach)-induced bronchoconstriction with an ED(50) value of 0.15 nmol/kg. The effect was sustained over a period of 24 h, with a residual 57% inhibition 48 h after antagonist administration at 1 nmol/kg. In conscious guinea pigs, inhaled CHF5407 inhibited Ach-induced bronchoconstriction for at least 24 h as did tiotropium at similar dosages. Cardiovascular parameters in anesthetized guinea pigs were not significantly changed by CHF5407, up to 100 nmol/kg i.v. and up to 1000 nmol/kg i.t. In conclusion, CHF5407 shows a prolonged antibronchospastic activity both in vitro and in vivo, caused by a very slow dissociation from M3 receptors. In contrast, CHF5407 is markedly short-acting at M2 receptors, a behavior not shared by tiotropium.

Contamination of drinking water sources during the rainy season in an urban post-conflict community in Guinea Bissau: implications for sanitation priority.

Since the 1998 civil warcholera outbreaks and waterborne infections have been a major cause of morbidity and mortality during the rainy season in Guinea Bidsau. Our survey aims at: (1) describing the distribution, characteristics and use of water sources and sewage facilities in a central area of the capital city of Bissau; (2) determining the microbiological quality of drinking water during the rainy season. After mapping of the Cuntum 3 study area, water sources' and latrines' location, characteristics and use were determined by visual inspection and interviews with householders. Microbiological analyses were peformed from water sources for evaluation of total Coliforms, E. coli, Enterococcus faecalis. Twelve water sources (9 wells, 3 taps) and 15 latrines were identified and used by 444 inhabitants. Water sources and latrines were at less than 5 meters distance apart. Wells were self-built, hand-dug, shallow (4-6 meters), unprotected. Taps were located outdoor. Latrines were self-built, open air, unprotected. None of the houses had a bathroom. Maintenance of wells, taps and latrines is not performed on regular basis and well's handling habits are not safe. Well and tap water showed heavy faecal contamination with more than 1000 CFU/100 ml. The contamination of drinking water in Bissau due to poor construction, maintenance and improperuse ten years after the civil war, demonstrates the need to allocate resources after conflicts in the area of water and sanitation. Both should be included as a priority in post-conflict reconstruction programs in order to reduce cholera outbreaks and diarrhoea related mortality.

Resonantly absorbing one-dimensional photonic crystals.

A compact theoretical description of the effects of dissipation on the propagation of light waves through a multilayer periodic mirror built from resonant absorbing atoms is presented. Depending on the lattice periodicity, ultranarrow photonic gaps, weak polaritonic gaps, as well as rather atypical gap structures may be observed. Because of the atom's absorption line shape Bloch gap modes may acquire quite a cumbersome structure which is thoroughly studied here or which may even disappear when dissipation becomes sufficiently strong. The same approach well applies also to resonantly absorbing photonic crystals based on excitonic resonances.

Nanoscale elemental quantification in heterostructured SiGe nanowires.

The nanoscale chemical characterization of axial heterostructured Si1-xGex nanowires (NWs) has been performed using scanning Auger microscopy (SAM) through local spectroscopy, line-scan and depth profile measurements. Local Auger profiles are realized with sufficient lateral resolution to resolve individual nanowires. Axial and radial composition heterogeneities are highlighted. Our results confirm the phenomenon of Ge radial growth forming a Ge shell around the nanowire. Moreover, quantification is performed after verifying the absence of preferential sputtering of Si or Ge on a bulk SiGe sample. Hence, reliable results are obtained for heterostructured NW diameters higher than 100 nm. However, for smaller sizes, we have noticed that the sensitivity factors evaluated from bulk samples cannot be used because of edge effects occurring for highly topographical features and a modified contribution of backscattered electrons.

Preclinical evaluation of CHF3381 as a novel antiepileptic agent.

CHF3381 [n-(2-indanyl)-glycinamide hydrochloride] has been selected on the basis of a screening program as the compound displaying the highest anticonvulsant activity in the maximal electroshock seizure (MES) test and the best therapeutic index with reference to the rotarod test in mice and rats. In this study, the antiepileptic activity and the behavioural toxicity of CHF3381 were characterised in multiple model systems. CHF3381 effectively prevented MES-induced convulsions when administered i.p. (ED50, 24 mg/kg and 7.5 mg/kg) or p.o. (ED50, 21 mg/kg and 21 mg/kg) in both mice and rats, respectively. The time course of oral anti-MES activity in the rat was related to the brain concentration profile of unchanged CHF3381. Interestingly, the brain drug levels were about 4-5 times higher than in plasma. CHF3381 was very effective in mice against picrotoxin-, and i.c.v. N-methyl-D-aspartate (NMDA)-induced hind limb tonic extension (ED50 Approximately/=10 mg/kg), but was a weaker antagonist of 4-amynopyridine- and bicuculline-induced tonic seizures (ED50 approximately/=100 mg/kg), and ineffective against pentylentetrazole- and picrotoxin-induced clonic seizures. CHF3381 antagonised the behavioural effects and lethality of i.p. administered NMDA (ED50 = 57 mg/kg p.o.), indicating that the compound may act as a functional NMDA antagonist. In keeping with this idea, CHF3381 weakly displaced [(3)H]-TCP from binding to NMDA receptor channels (Ki, 8.8 microM). In the rat amygdala kindling model, CHF3381 was more efficient against kindling development than against kindled seizures (minimally active dose = 80 vs. 120 mg/kg i.p). Furthermore, it significantly increased the seizure threshold in kindled rats at relatively low doses (40 mg/kg i.p.). In contrast with MK-801-induced hyperactivity, CHF3381 moderately reduced the spontaneous locomotor activity in mice at anticonvulsant doses. Toxic effects on motor performance (rotarod test) were found at high doses only (TD50 approximately/= 300 mg/kg p.o., congruent with 100 mg/kg i.p. in both mice and rats). Furthermore, CHF3381 did not impair passive avoidance and Morris water maze responding in the therapeutic range of doses. Finally, the development of tolerance after repeated doses was negligible. These data indicate that CHF3381 exerts anticonvulsant and antiepileptogenic effects in various seizure models and possesses good therapeutic window, with scarce propensity to cause neurological side-effects.

Vavilov-Cherenkov effect in a driven resonant medium.

The Vavilov-Cherenkov effect in a dispersive and resonant absorbing medium is substantially modified by the presence of an external electromagnetic field. Depending on the field parameters and configuration we anticipate a remarkable increase of the emission yield at resonance. Our predictions are implemented by numerical estimates for cuprous oxide (Cu2O) where the yield turns out to be one to two orders of magnitude that obtained in the absence of the field.

The consequence of land mines on public health.

An estimated 110 million land mines scattered in 64 countries continue to terrorize people and destroy human lives long after wars and fighting have ceased. Despite efforts to clear these devices, their numbers continue to increase and their presence constitutes a substantial threat to public health in affected countries. Direct consequences include both the physical and emotional injuries from the impact, flying debris, and structural collapse associated with their detonation. Indirect consequences include increases in the incidence of waterborne diseases, diarrhea, malnutrition, infectious diseases, and spread of the human immunodeficiency virus associated with the increased use of blood. Those at highest risk of these later consequences are mostly the disadvantaged poor, especially children. Psychiatric disorders, such as post-traumatic stress disorder, occur in those not directly injured as well as those physically wounded by the explosion. Besides efforts to ban production, stockpiling and export of land mines, a comprehensive and integrated health program aimed at the prevention, treatment, and rehabilitation of those injured directly or indirectly by land mines is needed urgently. Strategies should include mine-awareness programs, enhanced transport of those directly injured, training the villagers in first aid, augmenting the capacity and quality of treatment facilities, improving the psychological support and treatment capabilities, development of rehabilitation programs, and the institution and enhancement of public-health programs directed at the indirect consequences associated with the presence of land mines. Land mines constitute a major public health problem in the world that must be addressed.

[Clinical approach to constipation: proposal of a diagnostic and therapeutic protocol]. / Contributo all'inquadramento clinico della stipsi: proposta di protocollo diagnostico e terapeutico.

A study concerning constipation in children has been carried out in the University Department of Pediatrics and in the Division of Pediatric Surgery of Parma with the aim of reaching an homogeneus approach: it has been applied to 20 children up to now observed for such a problem. According to clinical and anamnestic criteria, children were divided into 3 groups on the basis of different degree of constipation: 1) moderate, 2) mild, 3) severe. Children belonging to the 2nd and 3rd group underwent barium enema and rectal manometry; two cases of ultrashort Hirschprung's disease and 7 cases of functional megarectum were diagnosed. Different treatment have been employed for each group and good results were observed in 18 cases. The AA. briefly discuss the different aspects concerning constipation and its therapy in childhood including diet, drugs, psychotherapy and surgical treatment.