The importance of body mass normalisation for ultrasound measurements of the morphology of oblique abdominis muscles: the effect of age, gender, and sport practice

Some studies have not considered body mass as a confounder in analysis of oblique abdominis muscles (OAM) (including the oblique externus [OE] and oblique internus [OI]), which may have led to improper interpretation of results. To assess the differences in the effect of age, gender, and physical activity between normalised for body mass and actual values of the OAM as well as to establish the effect of age, gender, and physical activity on normalised for body mass OAM thicknesses in adolescents. A real-time ultrasound was used to obtain images of the OAM. Body mass normalisation for OAM thicknesses was performed with allometric scaling and the following equations: Allometric-scaled OE = OE thickness/body mass0.88; Allometric-scaled OI = OI thickness/body mass0.72. Analysis showed that boys have significantly thicker OAM than girls, and those who practise sports have thicker OAM than non-active individuals. For allometric-scaled OAM, there was only a significant gender effect, where boys have thicker allometric-scaled OAM than girls. There was a significant correlation between participants’ age and the actual value of the OAM. The correlations between age and allometric-scaled OAM were insignificant. An analysis of OAM without body mass normalisation can lead to improper interpretation of study results. Thus, future studies should analyse OE and OI thickness measurements after normalisation rather than actual values. In the adolescent population, there is no effect of age and physical activity on allometric-scaled OAM; males have thicker allometric-scaled OAM than females. (Folia Morphol 2018; 77, 1: 123–130

New media, familiar dynamics: academic hierarchies influence academics' following behaviour on Twitter

For what reasons do academics follow one another on Twitter? Robert Jäschke, Stephanie B. Linek and Christian P. Hoffmann analysed the Twitter activity of computer scientists and found that while the quality of information provided by a Twitter account is a key motive for following academic colleagues, there is also evidence of a career planning motive. As well as there being reciprocal following between users of the same academic status (except, remarkably, between PhD researchers), a form of strategic politeness can be observed whereby users follow those of higher academic status without necessarily being followed back. The emerging academic public sphere facilitated by Twitter is largely shaped by dynamics and hierarchies all too familiar to researchers struggling to plot their careers in academia

Differential Dynamic Microscopy of Bacterial Motility

We demonstrate 'differential dynamic microscopy' (DDM) for the fast, high throughput characterization of the dynamics of active particles. Specifically, we characterize the swimming speed distribution and the fraction of motile cells in suspensions of Escherichia coli bacteria. By averaging over ~10^4 cells, our results are highly accurate compared to conventional tracking. The diffusivity of non-motile cells is enhanced by an amount proportional to the concentration of motile cells.Comment: 4 pages, 4 figures. In this updated version we have added simulations to support our interpretation, and changed the model for the swimming speed probability distribution from log-normal to a Schulz distribution. Neither modification significantly changes our conclusion

MLPH Genotype—Melanin Phenotype Correlation in Dilute Dogs

Coat color dilution in dogs is a specific pigmentation phenotype caused by a defective transport of melanosomes leading to large clumps of pigment. It is inherited as a Mendelian autosomal recessive trait and may be accompanied by hair loss, the so-called color dilution alopecia (CDA), or black hair follicular dysplasia (BHFD). We previously identified the noncoding c.-22G>A transition in the melanophilin gene (MLPH) as a candidate causative mutation for the dilute phenotype. We have now extended our study and genotyped 935 dogs from 20 breeds segregating for dilute coat color. The dilute-associated A allele segregates in many different breeds suggesting an old mutation event. We also investigated skin biopsies of dogs suspected of having either CDA or BHFD, and our data clearly indicate that the dilute mutation is required but not sufficient to develop clinical signs of the disease. The risk to develop CDA/BHFD seems to be breed specific. Interestingly, 22 out of 29 dogs with clinical signs of CDA/BHFD have clumped melanin in the epidermis, the follicular epithelium, and the hair shafts, whereas in dilute dogs without clinical disease, clumped melanin is only found in the follicular epithelium and the hair shafts but not in the epidermi

Enhanced gas-liquid mass transfer of an oscillatory constricted-tubular reactor

The mass transfer performance has been tested for gas-liquid flow in a new tubular reactor system, the oscillating mesotube (OMT), which features the oscillatory movement of fluid across a series of smooth constrictions located periodically along the vertical 4.4 mm internal diameter tube. The effect of the fluid oscillations (frequency,f, and center-to-peak amplitude, x(0), in the range of 0-20 s(-1) and 0-3 mm, respectively) on the overall volumetric mass transfer coefficient (k(L)a) has been tested by measuring the oxygen saturation levels with a fiber-optical microprobe (oxygen micro-optrode), and a mathematical model has been produced to describe the oxygen mass transport in the OMT. The oxygen mass transfer rates were about I order of magnitude higher (k(L)a values up to 0.16 s(-1)) than those values reported for gas-liquid contacting in a 50 mm internal diameter oscillatory flow reactor (OFR), for the same peak fluid oscillatory velocity, i.e., 2 pi fx(0). This represents remarkable oxygen transfer efficiencies, especially when considering the very low mean superficial gas velocity involved in this work (0.37 mm s(-1)). The narrower constrictions helped to increase the gas fraction (holdup) by reducing the rise velocity of the bubbles. However, the extent of radial mixing and the detachment of vortex rings from the surface of the periodic constrictions are actually the main causes of bubbles retention and effective gas-liquid contacting and are, thus, responsible for the enhancement of k(L)a in the OMT.N.R. thanks the Portuguese Foundation for Science and Technology (FCT) for financial support of his work (SFRH/BD/6954/2001)

Twenty Years After the Velvet Revolution: Shifts in Czech Adolescents’ Perceptions of Family, School, and Society

Families and schools are traditionally seen as substantial socialization agents forming adolescents’ social values and their views of society. Special attention is paid to the question whether the relative importance of these influences remains stable in times of major social changes. In this study, two different generations of Czech middle adolescents are compared: (a) the “post-totalitarian” generation that grew up in the last decade of the communist regime and entered adolescence during the time of rapid political and socioeconomic changes (data collected in 1995) and (b) the current generation without personal experience with the communist regime, raised in a stable democratic society (data collected in 2010). Both groups of participants (total N = 2,127, aged from 14 to 17 years) were administered an identical questionnaire. First, we examined the changes in adolescents’ perception and evaluation of the society over the last 15 years. Today’s adolescents perceive society more as a community and their future orientations are more focused on materialistic and less on environmental values. While the emotional relationship between the children and parentsremains the same, adolescents learn a somewhat different message in the family, emphasizing self-reliance. School environment is perceived more as positive and engaging than 15 years ago. Second, we predicted adolescents’ social views and values from their assessment of family and school environment. Our results show that the effect of parental values on adolescents’ value orientations is higher in the current generation. Positive school environment contributes to the development of socially responsible orientations despite the changes in society

Boundary Limitation of Wavenumbers in Taylor-Vortex Flow

We report experimental results for a boundary-mediated wavenumber-adjustment mechanism and for a boundary-limited wavenumber-band of Taylor-vortex flow (TVF). The system consists of fluid contained between two concentric cylinders with the inner one rotating at an angular frequency $\Omega$. As observed previously, the Eckhaus instability (a bulk instability) is observed and limits the stable wavenumber band when the system is terminated axially by two rigid, non-rotating plates. The band width is then of order $\epsilon^{1/2}$ at small $\epsilon$ ($\epsilon \equiv \Omega/\Omega_c - 1$) and agrees well with calculations based on the equations of motion over a wide $\epsilon$-range. When the cylinder axis is vertical and the upper liquid surface is free (i.e. an air-liquid interface), vortices can be generated or expelled at the free surface because there the phase of the structure is only weakly pinned. The band of wavenumbers over which Taylor-vortex flow exists is then more narrow than the stable band limited by the Eckhaus instability. At small $\epsilon$ the boundary-mediated band-width is linear in $\epsilon$. These results are qualitatively consistent with theoretical predictions, but to our knowledge a quantitative calculation for TVF with a free surface does not exist.Comment: 8 pages incl. 9 eps figures bitmap version of Fig

The Terminal Immunoglobulin-Like Repeats of LigA and LigB of Leptospira Enhance Their Binding to Gelatin Binding Domain of Fibronectin and Host Cells

Leptospira spp. are pathogenic spirochetes that cause the zoonotic disease leptospirosis. Leptospiral immunoglobulin (Ig)-like protein B (LigB) contributes to the binding of Leptospira to extracellular matrix proteins such as fibronectin, fibrinogen, laminin, elastin, tropoelastin and collagen. A high-affinity Fn-binding region of LigB has been localized to LigBCen2, which contains the partial 11th and full 12th Ig-like repeats (LigBCen2R) and 47 amino acids of the non-repeat region (LigBCen2NR) of LigB. In this study, the gelatin binding domain of fibronectin was shown to interact with LigBCen2R (KD = 1.91±0.40 µM). Not only LigBCen2R but also other Ig-like domains of Lig proteins including LigAVar7'-8, LigAVar10, LigAVar11, LigAVar12, LigAVar13, LigBCen7'-8, and LigBCen9 bind to GBD. Interestingly, a large gain in affinity was achieved through an avidity effect, with the terminal domains, 13th (LigA) or 12th (LigB) Ig-like repeat of Lig protein (LigAVar7'-13 and LigBCen7'-12) enhancing binding affinity approximately 51 and 28 fold, respectively, compared to recombinant proteins without this terminal repeat. In addition, the inhibited effect on MDCKs cells can also be promoted by Lig proteins with terminal domains, but these two domains are not required for gelatin binding domain binding and cell adhesion. Interestingly, Lig proteins with the terminal domains could form compact structures with a round shape mediated by multidomain interaction. This is the first report about the interaction of gelatin binding domain of Fn and Lig proteins and provides an example of Lig-gelatin binding domain binding mediating bacterial-host interaction

A new method for post-translationally labeling proteins in live cells for fluorescence imaging and tracking

This work was funded by the Raymond and Beverley Sackler Institute for Biological, Physical, and Engineering sciences [to L.R.]; the National Institute of Health [Grant nos. GM118528 and CA209992 to M. H. and L. R.]; the Medical Research Council [Grant no. MR/K001485 to U.S.L. and J. M. E.]; a Leverhulme Trust Visiting Professorship [to L. R.]; and Royal Society of Edinburgh [Caledonian Scholarship to O.K.M.].We present a novel method to fluorescently label proteins, post-translationally, within live Saccharomycescerevisiae. The premise underlying this work is that fluorescent protein (FP) tags are less disruptive to normal processing and function when they are attached post-translationally, because target proteins are allowed to fold properly and reach their final subcellular location before being labeled. We accomplish this post-translational labeling by expressing the target protein fused to a short peptide tag (SpyTag), which is then covalently labeled in situ by controlled expression of an open isopeptide domain (SpyoIPD, a more stable derivative of the SpyCatcher protein) fused to an FP. The formation of a covalent bond between SpyTag and SpyoIPD attaches the FP to the target protein. We demonstrate the general applicability of this strategy by labeling several yeast proteins. Importantly, we show that labeling the membrane protein Pma1 in this manner avoids the mislocalization and growth impairment that occur when Pma1 is genetically fused to an FP. We also demonstrate that this strategy enables a novel approach to spatiotemporal tracking in single cells and we develop a Bayesian analysis to determine the protein’s turnover time from such data.PostprintPeer reviewe