Stabilized dried blood spot collection

During the collection phase of the dried blood spot method, practitioners need to ensure that there is no smearing of the blood sample on the filter paper or else readings from it will be invalid. This can be difficult to accomplish in the field if there is relative motion between the site of blood discharge on the finger and the filter paper. In this article, a gyroscope stabilization method is introduced and demonstrated to provide consistent and improved dried blood spot collection within a circular guide region notwithstanding the presence of rocking.     

Relationship between rocking behaviour and copulation termination in Lygaeus equestris

ABSTRACT. During copulation (end-to-end position) females of Lygaeus equestris L. (Heteroptera, Lygaeidae) show a sideways, stereotyped movement called 'rocking', the function of which has been unclear. Since copulation interferes with other behaviours, females exposed to excess copulation have a lowered fitness, and would benefit from being able to influence the termination of copulation. It is here argued that they do so by rocking. First, it is shown that the variance of in copula duration was lower in rocking than non-rocking pairs, presumably because long copulations are avoided. Second, the frequency of rocking individuals and the intensity of the behaviour are higher in gravid than in non-gravid females. Third, defecation is hindered by copulation, which could be one reason for young, not yet reproductive females wanting to terminate copulation. Last, rocking individuals defecate sooner and lay eggs sooner than non-rocking ones. The mechanism by which rocking might effect termination of copulation is discussed.     

Application of a two-dimensional disposable rocking bioreactor to bacterial cultivation for recombinant protein production

Disposable rocking bioreactors (RBs) are widely employed for cultivation of recombinant mammalian and insect cell lines, although the perception of inadequate mass transfer has prevented their application to bioprocesses based on microbial platforms. In this study, one-dimensional (1D) and two-dimensional (2D) RBs were assessed and compared with the conventional stirred tank reactor (STR) for recombinant therapeutic protein production in Escherichia coli. The comparison involved: (1) physical characterization of oxygen mass transfer efficiency and mixing intensity, (2) growth characteristics in batch cultivation, and (3) culture performance for the production of recombinant protein. Our results show that oxygen mass transfer was comparable between the 1D RB and STR at low working volume (WV), declining linearly with increasing WV, and was highest in the 2D RB for all tested WVs with the maximum mass transfer coefficient (k_La) at 3 L WV. Well mixing behavior was observed in all three systems for water and aqueous carboxymethylcellulose (CMC) solutions. Batch growth characteristics were similar in all bioreactor systems, although metabolite accumulation was significant in the 1D RB. Culture performance for the production of recombinant GST-hCD83ext (glutathione S-transferase-hCD83ext fusion protein) was similar in terms of soluble protein yield and inclusion body formation for all bioreactor systems.