Epitaxial Metal Electrodeposition Controlled by Graphene Layer Thickness.

Control over material structure and morphology during electrodeposition is necessary for material synthesis and energy applications. One approach to guide crystallite formation is to take advantage of epitaxy on a current collector to facilitate crystallographic control. Single-layer graphene on metal foils can promote "remote epitaxy" during Cu and Zn electrodeposition, resulting in growth of metal that is crystallographically aligned to the substrate beneath graphene. However, the substrate-graphene-deposit interactions that allow for epitaxial electrodeposition are not well understood. Here, we investigate how different graphene layer thicknesses (monolayer, bilayer, trilayer, and graphite) influence the electrodeposition of Zn and Cu. Scanning transmission electron microscopy and electron backscatter diffraction are leveraged to understand metal morphology and structure, demonstrating that remote epitaxy occurs on mono- and bilayer graphene but not trilayer or thicker. Density functional theory (DFT) simulations reveal the spatial electronic interactions through thin graphene that promote remote epitaxy. This work advances our understanding of electrochemical remote epitaxy and provides strategies for improving control over electrodeposition.

Melting, Crystallization, and Alloying Dynamics in Nanoscale Bismuth Telluride.

It is critical to understand the transformation mechanisms in layered metal chalcogenides to enable controlled synthesis and processing. Here, we develop an alumina encapsulation layer-based in situ transmission electron microscopy (TEM) setup that enables the investigation of melting, crystallization, and alloying of nanoscale bismuth telluride platelets while limiting sublimation in the high-vacuum TEM environment. Heating alumina-encapsulated platelets to 700 °C in situ resulted in melting that initiated at edge planes and proceeded via the movement of a sharp interface. The encapsulated melt was then cooled to induce solidification, with individual nuclei growing to form single crystals with the same basal plane orientation as the original platelet and nonequilibrium crystal shapes imposed by the encapsulation layer. Finally, heating platelets in the presence of antimony caused alloying and lattice strain, along with heterogeneous phase formation. These findings provide new insight into important transformation processes in layered metal chalcogenide materials.

Highly structured slow solar wind emerging from an equatorial coronal hole.

During the solar minimum, when the Sun is at its least active, the solar wind1,2 is observed at high latitudes as a predominantly fast (more than 500 kilometres per second), highly Alfvénic rarefied stream of plasma originating from deep within coronal holes. Closer to the ecliptic plane, the solar wind is interspersed with a more variable slow wind3 of less than 500 kilometres per second. The precise origins of the slow wind streams are less certain4; theories and observations suggest that they may originate at the tips of helmet streamers5,6, from interchange reconnection near coronal hole boundaries7,8, or within coronal holes with highly diverging magnetic fields9,10. The heating mechanism required to drive the solar wind is also unresolved, although candidate mechanisms include Alfvén-wave turbulence11,12, heating by reconnection in nanoflares13, ion cyclotron wave heating14 and acceleration by thermal gradients1. At a distance of one astronomical unit, the wind is mixed and evolved, and therefore much of the diagnostic structure of these sources and processes has been lost. Here we present observations from the Parker Solar Probe15 at 36 to 54 solar radii that show evidence of slow Alfvénic solar wind emerging from a small equatorial coronal hole. The measured magnetic field exhibits patches of large, intermittent reversals that are associated with jets of plasma and enhanced Poynting flux and that are interspersed in a smoother and less turbulent flow with a near-radial magnetic field. Furthermore, plasma-wave measurements suggest the existence of electron and ion velocity-space micro-instabilities10,16 that are associated with plasma heating and thermalization processes. Our measurements suggest that there is an impulsive mechanism associated with solar-wind energization and that micro-instabilities play a part in heating, and we provide evidence that low-latitude coronal holes are a key source of the slow solar wind.

Solar Wind Temperature Isotropy.

Reliable models of the solar wind in the near-Earth space environment may constrain conditions close to the Sun. This is relevant to NASA's contemporary innerheliospheric mission Parker Solar Probe. Among the outstanding issues is how to explain the solar wind temperature isotropy. Perpendicular and parallel proton and electron temperatures near 1 AU are theoretically predicted to be unequal, but in situ observations show quasi-isotropy sufficiently below the instability threshold condition. This has not been satisfactorily explained. The present Letter shows that the dynamical coupling of electrons and protons via collisional processes and instabilities may contribute toward the resolution of this problem.

Study of prevalence and parasite load of Schistosoma haematobium in schoolchildren in the Rosso region, Mauritania.

This study assessed the prevalence of schistosomiasis among 307 schoolchildren aged from 7 to 17 years at various schools in four districts in the Rosso region. Hematuria was observed among 17.5% (54/307) and Schistosoma hematobium eggs were found among 15.6% (48/307). We observed the highest prevalence rates (P = 0.003) among schoolchildren in the districts of Breun (19.75% ± 0.09), Tounguen (18.66% ±0.08) and PK 7 (18.42 % ±0.08). The statistical analysis showed that the differences in the prevalence, hematuria rate, and parasite load did not differ significantly by the schoolchildren's age and sex (P > 0.05). Schoolchildren in Demeldek were significantly (P = 0.003) less infested (5.33% ± 0.11) than those in the other districts. The parasite load ranged from 6 to 15 eggs/10 ml of urine. The malacological investigations conducted at the water points of each village visited showed the presence of Bulinus truncatis, Bulinus forskalii, Lymnaea natalanis, Biomphalariae feifferi and Melanoides tuberculata. These results show that schistosomiasis poses a public health problem in the region. To eradicate this parasitosis, it will be necessary to conduct more detailed malacological studies and combine several types of preventive actions.

[Study of prevalence of Toxoplasma gondii oocysts in the cats of Nouakchott]. / Étude de la prévalence des oocystes de Toxoplasma gondii chez le chat à Nouakchott.

The aim of the work was to evaluate the prevalence of Toxoplasma gondii oocyst shedding on a sample of 100 cats in five districts of Nouakchott, Mauritania. The faecal flotation method revealed that 23% ± 0.08 of cats which underwent the test excreted oocysts and the prevalence was influenced by age and sex. Excretion rates were significantly higher in neighborhoods of Basra (27.8 ± 0.2), Elmina (25 ± 0.13) and Netegue (20 ± 0.35). The average parasite number was less than 5 oocysts/5 g faeces. Hence, the results suggest that cats have an important role in the transmission of the zoonosis in Nouakchott.

Drug-induced hyperuricaemia and gout.

Hyperuricaemia is a common clinical condition that can be defined as a serum uric acid level >6.8 mg/dl (404 µmol/l). Gout, a recognized complication of hyperuricaemia, is the most common inflammatory arthritis in adults. Drug-induced hyperuricaemia and gout present an emergent and increasingly prevalent problem in clinical practice. Diuretics are one of the most important causes of secondary hyperuricaemia. Drugs raise serum uric acid level by an increase of uric acid reabsorption and/or decrease in uric acid secretion. Several drugs may also increase uric acid production. In this review, drugs leading to hyperuricaemia are summarized with regard to their mechanism of action and clinical significance. Increased awareness of drugs that can induce hyperuricaemia and gout, and monitoring and prevention are key elements for reducing the morbidity related to drug-induced hyperuricaemia and gout.

Critical appraisal of the clinical utility of sublingual immunotherapy in allergy.

Since it was introduced by Noon in 1911, allergen-specific immunotherapy or desensitization has been widely prescribed in the management of allergic diseases. Aimed at the etiology, it represents the only effective treatment for allergy. The basic mechanisms of immunotherapy are becoming better understood and allow us to improve this technique in the future. The sublingual immunotherapy as an alternative to subcutaneous route has been widely studied. Several clinical trials confirmed that sublingual immunotherapy is efficient in reducing allergic respiratory symptoms. The sublingual immunotherapy reduces the risk of developing serious side effects due to desensitization. We performed a literature review in order to remind the mechanisms of action and to demonstrate efficacy and tolerability of the sublingual immunotherapy in the treatment of allergic rhinoconjunctivitis and asthma and its impact on the quality of life.

Self-Similar Theory of Thermal Conduction and Application to the Solar Wind.

We propose a self-similar kinetic theory of thermal conductivity in a magnetized plasma, and discuss its application to the solar wind. We study a collisional kinetic equation in a spatially expanding magnetic flux tube, assuming that the magnetic field strength, the plasma density, and the plasma temperature decline as power laws of distance along the tube. We demonstrate that the electron kinetic equation has a family of scale-invariant solutions for a particular relation among the magnetic-, density-, and temperature-scaling exponents. These solutions describe the heat flux as a function of the temperature Knudsen number γ, which we require to be constant along the flux tube. We observe that self-similarity may be realized in the solar wind; for the Helios data 0.3-1 AU we find that the scaling exponents for density, temperature, and heat flux are close to those dictated by scale invariance. We find steady-state solutions of the self-similar kinetic equation numerically, and show that these solutions accurately reproduce the electron strahl population seen in the solar wind, as well as the measured heat flux.

WITHDRAWN: Allergen specific immunotherapy induced multi-organ failure.

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Membraneless glucose/O2 microfluidic biofuel cells using covalently bound enzymes.

We developed a new covalent enzyme immobilization technique compatible with lithography processes. Carbon nanotube electrodes patterned on glass slides were used to create Y-shaped membraneless glucose/O(2) microfluidic biofuel cells. An original extremophilic laccase, CotA from Bacillus subtilis, was used in the cathodic compartment of these miniaturized biofuel cells.

Density fluctuation spectrum of solar wind turbulence between ion and electron scales.

We present a measurement of the spectral index of density fluctuations between ion and electron scales in solar wind turbulence using the EFI instrument on the ARTEMIS spacecraft. The mean spectral index at 1 AU was found to be -2.75±0.06, steeper than predictions for pure whistler or kinetic Alfvén wave turbulence but consistent with previous magnetic field measurements. The steep spectra are also consistent with expectations of increased intermittency or damping of some of the turbulent energy over this range of scales. Neither the spectral index nor the flattening of the density spectra before ion scales were found to depend on the proximity to the pressure anisotropy instability thresholds, suggesting that they are features inherent to the turbulent cascade.

[Breast MRI: Artefacts and pitfalls]. / Artefacts et pièges en IRM mammaire.

Multiple artefacts and pitfalls may occur with breast MRI. Artefacts are secondary to the MR technique itself while pitfalls often are the result of human error. The most common artefacts include motion, pulsation, chemical shift and magnetic susceptibility. The most common pitfalls include improper contrast injection, poor patient positioning, improper placement of the ROI and improper characterization of physiological and iatrogenic contrast enhancement. The identification of these artefacts and pitfalls on breast MR images may reduce their impact or even eliminate them. The use of optimized protocols is necessary. It is important to explain to patients the sequence of the examination, ensure proper placement of the breasts in the coil and optimize the contrast injection. The ROI should always be placed over the most suspicious region of the lesion. Finally, it is recommended to perform the MRI during the second week of the menstrual cycle and to discontinue the use of HRT 2 months prior to scanning when possible.

[Prevalence and parasite load of urinary schistosomiasis in schoolchildren in the Wilaya of Gorgol in Mauritania]. / Etude de prévalence et de la charge parasitaire de la schistosomiase urinaire chez les écoliers dans la wilaya de Gorgol (Mauritanie).

The purpose of this article is to describe the findings of a study carried out in a cohort of 610 schoolchildren aged 6-15 years to determine the prevalence of urinary schistosomiasis in Wilaya of Gorgol. The schistosomiasis prevalence rate was high ranging from 1.3 to 30.1% depending on location and from 7.9 to 13.7% according to age. Parasite loads up to 14 eggs/10 mL were measured. Children living in the wet zone were significantly more infected than those living in the intermediate and dry zones (p = 0.005). However, no significant difference in prevalence was found according to age (p = 0.258). Infection rate and parasite burden were correlated with exposure in terms of frequency of contact with permanent water sources. Schoolchildren in frequent contact with breeding grounds were more vulnerable to urinary schistosomiasis. Areas along the riverbank were more affected than areas located away from the river or permanent water sources.

[Study of lesional aspects of hydatid echinococcosis in man in Mauritania: fertility, histology of hydatid cysts and protoscolex viability]. / Étude des aspects lésionnels de l'échinococcose hydatique chez l'Homme en Mauritanie: fertilité, histologie des kystes hydatiques et viabilité des protoscolex.

A lesional study on human hydatidosis (localization, fertility of cysts, protoscolex viability, and histological structure) focused on 63 human hydatid cysts from patients operated at CHN of Nouakchott was conducted during the period 1997-2007. The authors report the following results: the annual surgical incidence rate was in the order of 1.2% per 100,000 inhabitants. The lung was the primary localization of cyst (52%) followed by the liver (33%), spleen (4%), brain (3%), heart (2%), breasts (2%), kidney (2%), diaphragm (1%), and peritoneum (1%). The pulmonary cysts were larger and more fertile (76%) with protoscoleces also more viable (70%) compared with liver cysts (67-62%). The histology of hydatid cysts revealed in most cases a histological structure consistent with that described in the literature: thick cuticle, membrane proligeous, and capsules visible.

Hepatotoxicity of alpha-methyldopa in pregnancy.

Alpha-methyldopa is one of the most widely prescribed antihypertensive agents used during pregnancy. Despite its known potential hepatotoxicity, there have been only a few reports describing hepatotoxicity with the use of this drug during pregnancy. We report here a new case of acute hepatitis in a pregnant woman related to the use of alpha-methyldopa, and briefly review the literature on alpha-methyldopa-induced hepatotoxicity in pregnancy.

[Non-masslike enhancement on breast MRI: interpretation pearls]. / Le rehaussement sans masse en IRM mammaire: comment j'interprète?

The MR Breast Imaging Reporting and Data System (BI-RADS) lexicon of the American College of Radiology (ACR) includes a new lesion category defined as non-masslike enhancement. The purpose of this paper is to review the definition of this new entity, illustrate the main imaging features described in the BI-RADS lexicon and to propose a diagnostic approach based on data from the literature in order to achieve diagnosis and optimal patient management.