Fe and N self-diffusion in amorphous FeN: A SIMS and neutron reflectivity study

Simultaneous measurement of self-diffusion of iron and nitrogen in amorphous iron nitride (Fe86N14) using secondary ion mass spectroscopy (SIMS) technique has been done. In addition neutron reflectivity (NR) technique was employed to study the Fe diffusion in the same compound. The broadening of a tracer layer of 57Fe8615N14 sandwiched between Fe86N14 layers was observed after isothermal vacuum annealing of the films at different temperatures in SIMS measurements. And a decay of the Bragg peak intensity after isothermal annealing was observed in [Fe86N14/57Fe86N14]10 multilayers in NR. Strong structural relaxation of diffusion coefficient was observed below the crystallization temperature of the amorphous phase in both measurements. It was observed from the SIMS measurements that Fe diffusion was about 2 orders of magnitude smaller compared to nitrogen at a given temperature. The NR measurements reveal that the mechanism of Fe self-diffusion is very similar to that in metal-metal type metallic glasses. The structural relaxation time for Fe and N diffusion was found comparable indicating that the obtained relaxation time essentially pertain to the structural relaxation of the amorphous phase.Comment: 10 pages 12 figure

Atomic force microscopy analysis of nanoparticles in non-ideal conditions

Nanoparticles are often measured using atomic force microscopy or other scanning probe microscopy methods. For isolated nanoparticles on flat substrates, this is a relatively easy task. However, in real situations, we often need to analyze nanoparticles on rough substrates or nanoparticles that are not isolated. In this article, we present a simple model for realistic simulations of nanoparticle deposition and we employ this model for modeling nanoparticles on rough substrates. Different modeling conditions (coverage, relaxation after deposition) and convolution with different tip shapes are used to obtain a wide spectrum of virtual AFM nanoparticle images similar to those known from practice. Statistical parameters of nanoparticles are then analyzed using different data processing algorithms in order to show their systematic errors and to estimate uncertainties for atomic force microscopy analysis of nanoparticles under non-ideal conditions. It is shown that the elimination of user influence on the data processing algorithm is a key step for obtaining accurate results while analyzing nanoparticles measured in non-ideal conditions

Targeting the hypoxic fraction of tumours using hypoxia activated prodrugs

The presence of a microenvironment within most tumours containing regions of low oxygen tension or hypoxia has profound biological and therapeutic implications. Tumour hypoxia is known to promote the development of an aggressive phenotype, resistance to both chemotherapy and radiotherapy and is strongly associated with poor clinical outcome. Paradoxically, it is recognised as a high priority target and one therapeutic strategies designed to eradicate hypoxic cells in tumours are a group of compounds known collectively as hypoxia activated prodrugs (HAPs) or bioreductive drugs. These drugs are inactive prodrugs that require enzymatic activation (typically by 1 or 2 electron oxidoreductases) to generate cytotoxic species with selectivity for hypoxic cells being determined by (i) the ability of oxygen to either reverse or inhibit the activation process and (ii) the presence of elevated expression of oxidoreductases in tumours. The concepts underpinning HAP development were established over 40 years ago and have been refined over the years to produce a new generation of HAPs that are under preclinical and clinical development. The purpose of this article is to describe current progress in the development of HAPs focusing on the mechanisms of action, preclinical properties and clinical progress of leading examples

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Not AvailableThe study evaluated the effectiveness of 'Mass Vaccination Campaign (MVC)' implemented against the contagious transboundary OIE notified Peste des petits ruminants (PPR) in sheep and goats on the lines of 'pulse polio campaign' for humans in Chhattisgarh state, India. The effectiveness was evaluated on the axes of adequacy, financial viability under with and without MVC through differencing under various scenarios and options and programme impact from a farmer's perspective. The adequacy evaluation revealed that the reported outbreaks, diagnosed and death cases declined under PPR-MVC inconsonance with increased vaccination coverage. Furthermore, the seroconversion increased during post PPR-MVC implies elevated immunity levels in the sheep and goat population. The estimated mean mortality loss was USD 45.2 and USD 16.5 per animal in goats and sheep, respectively, whereas the treatment and opportunity cost of labour was USD 1.9 and USD 2.5 per animal respectively. Under the low PPR incidence scenario, benefit: cost ratio, net present value and internal rate of return were 4.9:1, 48.9 million USD and 146.6%, whereas it was 12.4:1,142.7 million USD and 430.4% and 13.5:1,156.7 million USD and 430.4% under medium and high incidence scenarios. Furthermore, the option of vaccinating 100% risk population during the first year followed by 30% during subsequent years to cover naïve population will maximize benefits than 100% coverage every year; nevertheless, benefits outweighs cost manifolds in both of these options. The farmers had a positive opinion on the overall services provided under PPR-MVC and the results provide the empirical evidence on effectiveness of 'mass vaccination' for its replication in other states of India or countries with similar socio-economic and rearing environments.Not Availabl

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Not AvailableThis cross-sectional study describes the seroprevalence of peste des petits ruminants (PPR) in goats in Andaman and Nicobar (AN) Islands, India during 2017–2018. A total of 392 goat serum samples were collected from 36 epidemiological units (epi-units) using a stratified random sampling procedure and were screened for PPR virus (PPRV) antibody using an indigenously developed PPR monoclonal antibody-based competitive enzyme-linked immunosorbent (ELISA) assay. The results showed that the overall 1.28% (0.01-0.03 at 95% confidence interval) and 1.39% apparent and true prevalence of PPRV antibodies in goats in the studied region. Further, a few samples from five epi-units have only shown marginal positive (percentage inhibition (PI) value ranged from 40.4 to 48.0) for PPRV antibodies with less than 30% seroprevalence in all the tested epi-units in the study region. The finding infers that the goat population in the region are generally free from PPRV antibodies, as there were neither PPR outbreaks reported nor PPR vaccination strategies practiced in goats in AN Islands. Further, the PPR immune protection in goats is almost nil, when compared with the mainland of India, where the disease is enzootic with varying percentage of seroprevalence and population immunity is being reported. This is first of its kind on the prevalence study of the PPRV antibodies in goats in a unique niche of AN archipelago of India.Not Availabl