Search Results (4)

Conserving micromosaics from the Gilbert collection at the Victoria and Albert Museum is a challenge due to their complex structure and fragility. Their highly polished decorative surface prevents access to the substrate, yet deterioration can affect both, and manifests as cracking, failure and losses of the substrate and grouting, and as yellowing and accumulation of dirt on the uppermost organic coating. In order to minimise any possible damage to the substrate while cleaning the surface with solvents, laser cleaning using an Er:YAG laser was investigated on various micromosaic objects. Tests were first conducted on a non-displayable bonbonnière, and digital microscopy and scanning electron microscopy were performed to investigate the effects of the laser on the different materials; the results were then compared to solvent-cleaning only. The combination leading to the most effective cleaning results was found to be laser irradiation at fluences up to 0.71 J·cm⁻² on the surface, followed by gentle swabbing with solvent. The surface was successfully cleaned with no changes induced on the materials, and a much lower amount of solvent was used. Following these successful preliminary tests, cleaning was undertaken on other pieces of the collection, and the outcome is presented in this study. The results show a great variability in terms of response of the materials to solvents, emphasising the need to consider each item on a case-by-case basis. Full article

Advanced paternal age increases the risk of transmitting de novo germline mutations, particularly missense mutations activating the receptor tyrosine kinase (RTK) signalling pathway, as exemplified by the FGFR3 mutation, which is linked to achondroplasia (ACH). This risk is attributed to the expansion of spermatogonial stem cells carrying the mutation, forming sub-clonal clusters in the ageing testis, thereby increasing the frequency of mutant sperm and the number of affected offspring from older fathers. While prior studies proposed a correlation between sub-clonal cluster expansion in the testis and elevated mutant sperm production in older donors, limited data exist on the universality of this phenomenon. Our study addresses this gap by examining the testis-expansion patterns, as well as the increases in mutations in sperm for two FGFR3 variants—c.1138G>A (p.G380R) and c.1948A>G (p.K650E)—which are associated with ACH or thanatophoric dysplasia (TDII), respectively. Unlike the ACH mutation, which showed sub-clonal expansion events in an aged testis and a significant increase in mutant sperm with the donor’s age, as also reported in other studies, the TDII mutation showed focal mutation pockets in the testis but exhibited reduced transmission into sperm and no significant age-related increase. The mechanism behind this divergence remains unclear, suggesting potential pleiotropic effects of aberrant RTK signalling in the male germline, possibly hindering differentiation requiring meiosis. This study provides further insights into the transmission risks of micro-mosaics associated with advanced paternal age in the male germline. Full article

According to the study of frozen deposits in the territory south of the Taz Peninsula, geochemical processes are considered under the hydrocarbon migration from the lower productive complex. An analysis of the cryolithological structure of the frozen stratum was performed, and the composition of the gas and authigenic associations was studied. It was shown that the migration of gases is caused by shear deformations with the formation of cryogenic textures with the presence of gas-bearing ice crystallites on slip surfaces. It was found that the migration of hydrocarbons causes significant local changes in pH/Eh parameters in the frozen stratum and determines the micromosaic distribution of sulfate and iron reduction processes that lead to the formation (including microbiological processes) of various forms of iron: sulphides, carbonates and oxides. Full article

Microfluidic-based micromosaic technology has allowed the pattering of recognition elements in restricted micrometer scale areas with high precision. This controlled patterning enabled the development of highly multiplexed arrays multiple analyte detection. This arraying technology was first introduced in the beginning of 2001 and holds tremendous potential to revolutionize microarray development and analyte detection. Later, several microfluidic methods were developed for microarray application. In this review we discuss these novel methods and approaches which leverage the property of microfluidic technologies to significantly improve various physical aspects of microarray technology, such as enhanced imprinting homogeneity, stability of the immobilized biomolecules, decreasing assay times, and reduction of the costs and of the bulky instrumentation. Full article