Structural and Compositional Analysis of Feathers of Sunbird Nectarinia Asiatica

The plumage of many birds is highly attractive, especially when thefeathers are patterned in strongly contrasting colours. Orange colours are generally caused by pigments that selectively absorb short-wavelength light. When these pigments are embedded in a diffusive medium, only the long-wavelength part of incident broadband light is reflected and scattered. In contrast, blue or green animal coloration is virtually always due to periodic structures that reflect and scatter incident light of a restricted short-wavelength range(Srinivasarao, 1999; Vukusic and Sambles, 2003; Kinoshita and Yoshioka, 2005; Prum, 2006). Pigmentary and structural coloration are often found simultaneously, not only in birds but also in many other animals, for example butterflies, beetles and lizards (Kinoshita,2008). Birds possess various pigment classes, for instance carotenoids, pterins, porphyrins, psittacofulvins and melanins (McGraw, 2006; Hill and McGraw, 2006), and various mechanisms of structural colouration, namely thin films, multilayers, photonic crystals, keratin spongy nanostructures and nanofibres (e.g. Durrer, 1977; Shawkey et al., 2003;Shawkey et al., 2006; Yoshioka et al., 2007; Doucet and Meadows, 2009; Prum et al., 2009; Stavenga et al., 2010; D’Alba et al., 2011). The predominant location of colouration is the feathers, often either the barbs or the barbules. Structural coloration of avian skin have been long hypothesized to be produced by incoherent(Rayleigh /Tyndall )scattering. Avian plumage color have emerged recently as model system for investigating the type of information that can be signaled by showy sexual display in birds.The non pigmentary colors of the tissues of living organism are produced by physical interaction of light with nanostructures in the tissues. The brilliant iridescent color appearances of many avian feathers are produced by complex optical phenomena. They principally arise from coherent light scattering from self-assembled quasi-ordered structures that have a spatially periodic variation in refractive index. Iridescent structural colors in biology exhibit sophisticated spatially-varying reflectance properties that depend on both the illumination and viewing angles. The classification of such spectral and spatial information in iridescent structurally colored surfaces is important to elucidate the functional role of irregularity and to improve understanding of color pattern formation at different length scale

DETERMINING THE ACOUSTIC FIELD DISTRIBUTION OF ULTRASONIC MULTI-ELEMENT PROBES

The paper presents a universal method of determining the distribution of acoustic field of multi-element probes designed for applications in ultrasound transmission tomography (UTT). This method allows us to calculate the acoustic field for different sectors of the probe with assigned geometry of elementary transducers' location. The idea is to sum acoustic fields generated by all elementary transducers with the use of geometrical transformations of coordinates of location of the discussed points of the acoustic field against each of the transducers. In order to verify the calculation results measurements of acoustic field distribution were also carried out for selected sectors of these probes. On the basis of an analysis of calculation results the size of electronically switched transmitting sector was optimized (in the sense of the number of concurrently radiating elementary transducers) for a linear and a ring ultrasonic multi-element probes from the point of view of their use for visualizing the inside of a biological structure by means of UTT. acoustic field; ultrasonic multi-element probes; piezoelectric transducers; ultrasound transmission tomograph

A study of a parametric method for the snow reflection coefficient estimation using air-coupled ultrasonic waves

In this paper, a method for estimating snow pressure reflection coefficient based on non-contact ultrasound examination is described. A constant frequency and air-coupled ultrasound pulses were used in this study, which incorporates a parametric method for reflected energy estimation. The experimental part was carried out in situ in the Antarctic, where the snow parameters were measured along with meteorological data. The proposed method represents a promising alternative for estimating the snow-water equivalent, since it uses a parametric approach, which does not require measurements of absolute values for acoustic pressure

Significantly altered peripheral blood cell DNA methylation profile as a result of immediate effect of metformin use in healthy individuals

Funding Information: The work was supported by the European Regional Development Fund under the project “Investigation of interplay between multiple determinants influencing response to metformin: search for reliable predictors for efficacy of type 2 diabetes therapy” (Project Nr.: 1.1.1.1/16/A/091). Publisher Copyright: © 2018 The Author(s).Background: Metformin is a widely prescribed antihyperglycemic agent that has been also associated with multiple therapeutic effects in various diseases, including several types of malignancies. There is growing evidence regarding the contribution of the epigenetic mechanisms in reaching metformin's therapeutic goals; however, the effect of metformin on human cells in vivo is not comprehensively studied. The aim of our study was to examine metformin-induced alterations of DNA methylation profiles in white blood cells of healthy volunteers, employing a longitudinal study design. Results: Twelve healthy metformin-naïve individuals where enrolled in the study. Genome-wide DNA methylation pattern was estimated at baseline, 10 h and 7 days after the start of metformin administration. The whole-genome DNA methylation analysis in total revealed 125 differentially methylated CpGs, of which 11 CpGs and their associated genes with the most consistent changes in the DNA methylation profile were selected: POFUT2, CAMKK1, EML3, KIAA1614, UPF1, MUC4, LOC727982, SIX3, ADAM8, SNORD12B, VPS8, and several differentially methylated regions as novel potential epigenetic targets of metformin. The main functions of the majority of top-ranked differentially methylated loci and their representative cell signaling pathways were linked to the well-known metformin therapy targets: regulatory processes of energy homeostasis, inflammatory responses, tumorigenesis, and neurodegenerative diseases. Conclusions: Here we demonstrate for the first time the immediate effect of short-term metformin administration at therapeutic doses on epigenetic regulation in human white blood cells. These findings suggest the DNA methylation process as one of the mechanisms involved in the action of metformin, thereby revealing novel targets and directions of the molecular mechanisms underlying the various beneficial effects of metformin. Trial registration: EU Clinical Trials Register, 2016-001092-74. Registered 23 March 2017, https://www.clinicaltrialsregister.eu/ctr-search/trial/2016-001092-74/LV.Peer reviewe

Microbiome symbionts and diet diversity incur costs on the immune system of insect larvae.

Communities of symbiotic microorganisms that colonize the gastrointestinal tract play an important role in food digestion and protection against opportunistic microbes. Diet diversity increases the number of symbionts in the intestines, a benefit that is considered to impose no cost for the host organism. However, less is known about the possible immunological investments that hosts have to make in order to control the infections caused by symbiont populations that increase because of diet diversity. Using taxonomical composition analysis of the 16S rRNAV3 region, we show that enterococci are the dominating group of bacteria in the midgut of the larvae of the greater wax moth (Galleria mellonella). We found that the number of colony-forming units of enterococci and expressions of certain immunity-related antimicrobial peptide (AMP) genes such as Gallerimycin, Gloverin, 6-tox, Cecropin-D and Galiomicin increased in response to a more diverse diet, which in turn decreased the encapsulation response of the larvae. Treatment with antibiotics significantly lowered the expression of all AMP genes. Diet and antibiotic treatment interaction did not affect the expression of Gloverin and Galiomicin AMP genes, but significantly influenced the expression of Gallerimycin, 6-tox and Cecropin-D. Taken together, our results suggest that diet diversity influences microbiome diversity and AMP gene expression, ultimately affecting an organism's capacity to mount an immune response. Elevated basal levels of immunity-related genes (Gloverin and Galiomicin) might act as a prophylactic against opportunistic infections and as a mechanism that controls the gut symbionts. This would indicate that a diverse diet imposes higher immunity costs on organisms

Asymptotic Theory for Rayleigh and Rayleigh-Type Waves

Explicit asymptotic formulations are derived for Rayleigh and Rayleigh-type interfacial and edge waves. The hyperbolic–elliptic duality of surface and interfacial waves is established, along with the parabolic–elliptic duality of the dispersive edge wave on a Kirchhoff plate. The effects of anisotropy, piezoelectricity, thin elastic coatings, and mixed boundary conditions are taken into consideration. The advantages of the developed approach are illustrated by steady-state and transient problems for a moving load on an elastic half-space

Computer model of acoustic link in a pipe with a flowing gas medium. Part I: Perturbation of ultrasonic transducer directivity pattern

The paper presents an aeroacoustic range equation which makes it possible to elaborate a computer model of ultrasonic link in air for static conditions. The model was made in form of a computer program called KML. Extending the static model, a simulation of uItrasonic wave propagation in a pipeline with flowing air for different profiles of laminar and turbulent flow and different link parameters was performed. The simulation made it possible to work out a computer model of an acoustic link in flowing gas. The model as a computer program can be used to calculate disturbance of ultrasonic beam rays shape and directivity pattem perturbation. Directivity pattem of ultrasonic transmitting transducer, deformed by flowing medium, becomes non-axial symmetric. As a result of the flow, ultrasonic beam rays are curvilinear and the source directivity pattern depends on rectilinearly measured distance

Computer model of acoustic link in a pipe with a flowing gas medium. Part II: Accuracy improvement ot medium flow velocity determination

While constructing medium flow velocity meters with the use of the ultrasonic method, it is assumed, that the deviation of the ultrasonic beam caused by medium flow, is insignificant. The assumption seems to be correct, because the average flow velocity is usually much smaller than the ultrasonic wave velocity in a medium. Basing on the assumption, we can use a known expression, which makes it possible to calculate an average medium flow velocity through run-time measurement from the transmitter to the receiver and in an opposite direction. In the paper, it is shown, that the average flow velocity determined in this way, using the computer model of acoustic link in a pipe with a flowing gas medium, is measured with a significant error. This error depends on the flow pipe diameter, the transducer diameters and the means of placing the transducers in the pipe. Properly modifying the expression for ultrasonic run-time through flowing gas medium and taking into account the means of transducer placing in the pipe, we can eliminate the error related to the measurement geometry and we can find an optimum ultrasonic wave propagation angle