Highly pathogenic avian influenza affects vultures' movements and breeding output

An exceptional highly pathogenic avian influenza (HPAI) outbreak due to H5N1 virus genotypes belonging to clade 2.3.4.4.b has been affecting birds worldwide since autumn 2021.1,2,3 Mortality caused by viral infection has been well documented in poultry and more recently in wild birds, especially in seabird-breeding colonies.4,5,6 However, there is a critical lack of knowledge about how terrestrial birds deal with HPAI virus infections in terms of behavior and space use, especially during the breeding season.7,8,9 Understanding how birds move when they are infected could help evaluate the risk of spreading the virus at a distance among other populations of wild or domestic birds, this latter risk being especially important for commensal bird species. Through long-term GPS tracking, we described the changes in daily movement patterns of 31 adult griffon vultures Gyps fulvus in two French sites in 2022 compared with 3 previous years. In spring 2022, 21 vultures at both sites showed periods of immobility at the nest, during 5.6 days on average. Positive serological status of 2 individuals confirmed that they had been infected by HPAI viruses. Death was recorded for 3 of the 31 tracked individuals, whereas all others recovered and returned quickly to their foraging routine, although at least 9 birds failed breeding. Such immobility patterns and death rates were never observed in previous years and were not related to weather conditions. The high immobility behavior of infected birds could reduce the risks of transmission. The observed vulnerability to HPAI viruses questions the resistance of endangered vulture species worldwide if infected.

[Impact of prematurity on the optic nerve]

INTRODUCTION

Thanks to the progress made in the past few years in pediatric intensive care as well as the increased survival of preterm infants, the consequences of premature birth are increasingly well documented. With regard to ophthalmologic complications, retinopathy of prematurity is well described, but the optic nerve may also be affected. The goal of this study is to compare the optic nerves of preterm infants as a function of their gestational period with a control group of the same age.

MATERIALS AND METHODS

We conducted a case-control study pairing a full-term infant with each preterm infant. Inclusion criteria were: any child from 5- to 10-years-old, separated into three sub-groups according to their degree of prematurity. Variables were: cup/disc ratio, ocular biometry, intraocular pressure and RNFL thickness.

RESULTS

Thirty-seven preterm infants and 37 controls were included in the study. The mean age at the time of inclusion was 7.05 years for the preterm group and 7.19 years for the control group. No significant difference was observed in axial length or spherical equivalent (P=0.31 and P=0.98, respectively). No significant difference was observed in pachymetry or intraocular pressure (P=0.28 and P=0.22, respectively). We observed a significant increase of 0.1 in the cup/disc ratio of the preterm group compared to the control group (P<0.05). The preterm group cup/disc ratio was 0.36 versus 0.27 for the control group. No significant difference was observed in the 7 quadrants of RNFL between the two groups. However, when comparing infants born before 28 weeks gestation with the control group, we observed a mean decrease of 14.5 microns in the superior temporal sector (P=0.04), a 9 micron decrease in the global thickness G (P=0.03) and a 12.7 micron decrease in the nasal sector (P=0.01).

CONCLUSIONS

In the case of the studied children (aged 5 to 10), the reduced RNFL fiber thickness is a phenomenon dependent essentially on the stage of prematurity. It would be useful to follow these preterm populations over the long term and to compare them to a matched control group to be able to obtain functional results.

Antibacterial effects of chitosan powder: mechanisms of action

Chitosan, the deacetylated derivative of chitin, is a natural D-glucosamine polymer that can be extracted from the shells of seafood such as prawns crabs and lobsters. It can be used as a flocculent, plant disease resistant promoter, anti-cancer agent, wound healing promotion agent and antimicrobial agent. The aim of this paper is the study of the interaction between chitosan powder and various kinds of pathogen microorganisms potentially present in water. First of all, physico-chemical characterisations of chitin and chitosan powder were performed. The deacetylation yields were 35%, 60% and 80 +/- 10%. The experimental studies focused on the measurements of the mortality constant rate for various bacterial strains, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis and Staphylococcus saprophyticus. An explanation of the antibacterial mechanisms is proposed involving the cell wall disruption due to free amino groups present in chitosan.

A priori selection of the regularization parameters in emission tomography by Fourier synthesis

This paper describes how the stability of the inverse problem underlying emission tomography can be measured and controlled in clinical settings. We show how the Lanczos approximation provides a way to regularize a certain class of iterative reconstruction algorithms through a given level of noise or resolution in the slices and for a given acquisition protocol. Moreover, we show how the same Lanczos approximation can be used to decide when the iterative reconstruction algorithm actually converges for a given machine precision. These ideas are illustrated by means of reconstructions of simulated and actual emission datasets.

Drug/lactose co-micronization by jet milling to improve aerosolization properties of a powder for inhalation

The aim of this work was to formulate a powder for inhalation with fusafungine, a drug substance initially highly cohesive. The classical approach based on micronization by jet milling to prepare respirable drug particles and then blending with a carrier was first applied. A fractional factorial experimental design was implemented to screen six formulation parameters. The effect of drug/lactose co-micronization on aerosolization was then evaluated. In vitro deposition studies were performed with the twin stage glass impinger and the inhaler Spinhaler. Micronization did not induce DSC-detectable amorphization and gave a highly cohesive, poor flowable powder with a theoretical aerodynamic diameter of 5 microm. The powder was then blended with coarse lactose and optionally fine lactose. Unfortunately, the respirable fraction could not be optimized and remained below 10%. On the other hand, a co-micronized powder drug/fine lactose 50:50 gave a respirable fraction of 16%. Following blending with a carrier, the respirable fraction and the emitted dose fraction reached 23% and 69%, respectively. The use of a fine lactose grade for co-micronization was essential. In conclusion, this study demonstrated that co-micronization with a fine lactose is an efficient and simple strategy to formulate a powder for inhalation with enhanced aerosolization properties, especially for highly cohesive drug substance.

Chemical nucleation for CVD diamond growth

A new nucleation method to form diamond by chemically pretreating silicon (111) surfaces is reported. The nucleation consists of binding covalently 2,2-divinyladamantane molecules on the silicon substrate. Then low-pressure diamond growth was performed for 2 h via microwave plasma CVD in a tubular deposition system. The resulting diamond layers presented a good cristallinity and the Raman spectra showed a single very sharp peak at 1331 cm(-1), indicating high-quality diamonds.