Nitridation of InP(1 0 0) surface studied by synchrotron radiation

The nitridation of InP(1 0 0) surfaces has been studied using synchrotron radiation photoemission. The samples were chemically cleaned and then ion bombarded, which cleaned the surface and also induced the formation of metallic indium droplets. The nitridation with a Glow Discharge Cell (GDS) produced indium nitride by reaction with these indium clusters. We used the In 4d and P 2p core levels to monitor the chemical state of the surface and the coverage of the species present. We observed the creation of In-N and P-N bonds while the In-In metallic bonds decrease which confirm the reaction between indium clusters and nitrogen species. A theoretical model based on stacked layers allows us to assert that almost two monolayers of indium nitride are produced. The effect of annealing on the nitridated layers at 450 $^\circ$C has also been analysed. It appears that this system is stable up to this temperature, well above the congruent evaporation temperature (370 $^\circ$C) of clean InP(1 0 0): no increase of metallic indium bonds due to decomposition of the substrate is detected as shown in previous works [L. Bideux, Y. Ould-Metidji, B. Gruzza, V. Matolin, Surf. Interface Anal. 34 (2002) 712] studying the InP(1 0 0) surfaces

Understanding the clinical spectrum of complicated Plasmodium vivax malaria: a systematic review on the contributions of the Brazilian literature

The resurgence of the malaria eradication agenda and the increasing number of severe manifestation reports has contributed to a renewed interested in the Plasmodium vivax infection. It is the most geographically widespread parasite causing human malaria, with around 2.85 billion people living under risk of infection. The Brazilian Amazon region reports more than 50% of the malaria cases in Latin America and since 1990 there is a marked predominance of this species, responsible for 85% of cases in 2009. However, only a few complicated cases of P. vivax have been reported from this region. A systematic review of the Brazilian indexed and non-indexed literature on complicated cases of vivax malaria was performed including published articles, masters' dissertations, doctoral theses and national congresses' abstracts. The following information was retrieved: patient characteristics (demographic, presence of co-morbidities and, whenever possible, associated genetic disorders); description of each major clinical manifestation. As a result, 27 articles, 28 abstracts from scientific events' annals and 13 theses/dissertations were found, only after 1987. Most of the reported information was described in small case series and case reports of patients from all the Amazonian states, and also in travellers from Brazilian non-endemic areas. The more relevant clinical complications were anaemia, thrombocytopaenia, jaundice and acute respiratory distress syndrome, present in all age groups, in addition to other more rare clinical pictures. Complications in pregnant women were also reported. Acute and chronic co-morbidities were frequent, however death was occasional. Clinical atypical cases of malaria are more frequent than published in the indexed literature, probably due to a publication bias. In the Brazilian Amazon (considered to be a low to moderate intensity area of transmission), clinical data are in accordance with the recent findings of severity described in diverse P. vivax endemic areas (especially anaemia in Southeast Asia), however in this region both children and adults are affected. Finally, gaps of knowledge and areas for future research are opportunely pointed out

Vacancy Island Nucleation and Inverse Growth of InSb(110)

He beam scattering measurements of the erosion of the InSb(110) surface by low-energy Ar+ bombardment are reported. Layer-by-layer erosion is observed for surface temperatures above 510 K and is found to proceed by nucleation of vacancy islands, island growth, and coalescence. The average island distance is measured at different stages of the erosion process and it is found to evolve in good agreement with the rate equations derived from models of island growth by atomic deposition. A general increase of the average terrace width is also observed with increasing number of removed layers. The activation barrier for intralayer diffusion of InSb dimer vacancies is found to be Ed=1.14±0.06 e

Characterization of novel Acidobacteria exopolysaccharides with potential industrial and ecological applications

Acidobacteria have been described as one of the most abundant and ubiquitous bacterial phyla in soil. However, factors contributing to this ecological success are not well elucidated mainly due to difficulties in bacterial isolation. Acidobacteria may be able to survive for long periods in soil due to protection provided by secreted extracellular polymeric substances that include exopolysaccharides (EPSs). Here we present the first study to characterize EPSs derived from two strains of Acidobacteria from subdivision 1 belonging to Granulicella sp. EPS are unique heteropolysaccharides containing mannose, glucose, galactose and xylose as major components, and are modified with carboxyl and methoxyl functional groups that we characterized by Fourier transform infrared (FTIR) spectroscopy. Both EPS compounds we identified can efficiently emulsify various oils (sunflower seed, diesel, and liquid paraffin) and hydrocarbons (toluene and hexane). Moreover, the emulsions are more thermostable over time than those of commercialized xanthan. Acidobacterial EPS can now be explored as a source of biopolymers that may be attractive and valuable for industrial applications due to their natural origin, sustainability, biodegradability and low toxicity