Ink-Jetting of Polymers and Biomaterials

Inkjet printing is a very common and largely developed technology in desktop printers. A wide range of diverse technologies, with different principles of drop generation, fall into the inkjet printing category. Inkjet technology, particularly the drop-on-demand mode for drop generation, is widely applicable in micro/nano electromechanical systems (MEMS/NEMS) and is promising for further developments in this domain. We are investigating the potentials of inkjet printing for the fabrication of MEMS and NEMS as well as life-science applications. We utilise inkjet as a direct-patterning and non-contact method to dispense different polymers, with viscosities ranging from 1-60 mPas with droplet diameters ranging from 30-100 um. In our contribution, we describe applications of ink-jetting of polymers in combination with micro-moulding and on pre-structured substrates. Surface biotechnology is another application range where inkjet is a promising tool for rapid micro-arraying or cell sorting. In our contribution we present the use of inkjet as a tool for chemical dosing of biomaterials, and for transporting and sampling cells. Early results have shown almost no cell damage compared to the control, with printed cells remaining viable

Influence of the microwave radiation of different polarization state on transinactivation effect and viability of Drosophila

The influence of microwave radiation (λ = 3.8 mm, intensity P = 0.1 mW/cm2) on stocks and hybrids of Drosophila melanogaster was investigated. Irradiation at the egg stage negatively influences the reproductive ability and output of the imago, and induces significant changes in the eye pigmentation of the imago. The effect of radiation depends on the state of polarization of the radiation. Linearly polarized radiation and left circularly polarized radiation induce a decrease of pigmentation, right circularly polarized radiation induces an increase of it. As the amount of the pigment is connected with manifestation of the transinactivation effect and the reinforcement of the transinactivation effect is connected with an increase of the conjugation of homologous chromosomes, the authors draw the conclusion that left polarized radiation and linearly polarized radiation cause the reinforcement of the transinactivation effect. The authors suppose that the observed effect is connected with an increase of chromosome conjugation in the interphase nucleus; the action of the right circularly polarized radiation is connected with a reduction of the effect of transinactivation that, in its turn, is connected with a reduction of the conjugation of homologous chromosomes in the interphase nucleus

Calculating statistical power in Mendelian randomization studies

In Mendelian randomization (MR) studies, where genetic variants are used as proxy measures for an exposure trait of interest, obtaining adequate statistical power is frequently a concern due to the small amount of variation in a phenotypic trait that is typically explained by genetic variants. A range of power estimates based on simulations and specific parameters for two-stage least squares (2SLS) MR analyses based on continuous variables has previously been published. However there are presently no specific equations or software tools one can implement for calculating power of a given MR study. Using asymptotic theory, we show that in the case of continuous variables and a single instrument, for example a single-nucleotide polymorphism (SNP) or multiple SNP predictor, statistical power for a fixed sample size is a function of two parameters: the proportion of variation in the exposure variable explained by the genetic predictor and the true causal association etween the exposure and outcome variable. We demonstrate that power for 2SLS MR can be derived using the non-centrality parameter (NCP) of the statistical test that is employed to test whether the 2SLS regression coefficient is zero. We show that the previously published power estimates from simulations can be represented theoretically using this NCP-based approach, with similar estimates observed when the simulation-based estimates are compared with our NCP-based approach. General equations for calculating statistical power for 2SLS MR using the NCP are provided in this note, and we implement the calculations in a web-based application

GWAS of 126,559 individuals identifies genetic variants associated with educational attainment

A genome-wide association study (GWAS) of educational attainment was conducted in a discovery sample of 101,069 individuals and a replication sample of 25,490. Three independent single-nucleotide polymorphisms (SNPs) are genome-wide significant (rs9320913, rs11584700, rs4851266), and all three replicate. Estimated effects sizes are small (coefficient of determination R2 ≈ 0.02%), approximately 1 month of schooling per allele. A linear polygenic score from all measured SNPs accounts for ≈2% of the variance in both educational attainment and cognitive function. Genes in the region of the loci have previously been associated with health, cognitive, and central nervous system phenotypes, and bioinformatics analyses suggest the involvement of the anterior caudate nucleus. These findings provide promising candidate SNPs for follow-up work, and our effect size estimates can anchor power analyses in social-science genetics.Cornelius A. Rietveld ... Lyle J. Palmer ... et al