A macroscopic link between interhemispheric tract myelination and cortico-cortical interactions during action reprogramming

Myelination has been increasingly implicated in the function and dysfunction of the adult human brain. Although it is known that axon myelination shapes axon physiology in animal models, it is unclear whether a similar principle applies in the living human brain, and at the level of whole axon bundles in white matter tracts. Here, we hypothesised that in humans, cortico-cortical interactions between two brain areas may be shaped by the amount of myelin in the white matter tract connecting them. As a test bed for this hypothesis, we use a well-defined interhemispheric premotor-to-motor circuit. We combined TMS-derived physiological measures of cortico-cortical interactions during action reprogramming with multimodal myelin markers (MT, R1, R2* and FA), in a large cohort of healthy subjects. We found that physiological metrics of premotor-to-motor interaction are broadly associated with multiple myelin markers, suggesting interindividual differences in tract myelination may play a role in motor network physiology. Moreover, we also demonstrate that myelination metrics link indirectly to action switching by influencing local primary motor cortex dynamics. These findings suggest that myelination levels in white matter tracts may influence millisecond-level cortico-cortical interactions during tasks. They also unveil a link between the physiology of the motor network and the myelination of tracts connecting its components, and provide a putative mechanism mediating the relationship between brain myelination and human behaviour.

A Mini-review on Ultra Performance Liquid Chromatography

Chromatography is a widely used analytical tool for separating a mixture of compounds into individual component. High performance liquid chromatography (HPLC) is one of the most important methods used for the separation, identification and quantification of a compounds present in a mixture. It meets many criteria of analysis but its main drawbacks are it is relatively time consuming to run a chromatogram and consumes high amount of solvent compared to other analytical methods. There is a need to develop a method which can overcome these drawbacks of HPLC. Ultra performance liquid chromatography (UPLC) is the new approach which opens novel direction in the field of liquid chromatography. It works on similar principle but shows better performance than conventional HPLC. UPLC is a technique of liquid chromatography with improved runtime and sensitivity with less than 2 μm particle size. The UPLC separation process is carried out under very high pressure (up to100 MPa). Additionally, it reduces the cost of reagent with shorter run time as compared to conventional HPLC. This article updated until 2020, provides a general review on the principle, instrumentation and application of UPLC in different fields of science.

On a Special Edition of Manuscript Synodikoses — Literary Collections of the 18th Century

The type of Synodikos with a literary preface appeared at the end of the 16th century and developed and spread in the 17th century. It is believed that the study of the copies of the 18th century does not add essential information about the repertoire of collections of Synodikos. However, manuscripts can still be found that do not completely fit into the general picture of the ideas available in current science about the composition of literary collections of the late Synodikos. The article examines three handwritten front Synodikos books identified by the author, which differ significantly in the composition of literary prefaces from the general mass of those Synodikoses of the third edition common in the 18th century (I.V. Dergacheva). They are based on miniatures copied from engravings of various editions of the Synodikos by Leonty Bunin, and selected texts that match their meaning. A similar principle of compiling a moralistic collection was used in the Patriarch Adrian Synodikos (O.R. Khromov). The manuscripts in question have different origins and history of existence, but demonstrate thematic and stylistic affinity. They are also united by a curious combination in preface collections of poetic and prose texts. All this gives reason to say that in this case we are dealing with a special edition of the Synodikos — a literary collection that existed in the 18th century.

Determining the Tangential Velocity profile of a Rotating Fluid in a Static Container using Navier–Stokes equations

The shape of the liquid surface for a fluid present in a uniformly rotating cylinder is generally determined by making a Tangential velocity gradient along the radius of the rotating cylindrical container. A very similar principle can be applied if the direction of the produced velocity gradient is reversed, for which the source of rotation will be present at the central axis of the cylindrical vessel in which the liquid is present. Now if the described system is completely closed, the angular velocity will decrease as a function of time. But when the surface of the rotating fluid is kept free, then the Tangential velocity profile would be similar to that of the Taylor-Couette Flow, with a modification that; due to formation of a curvature at the surface, the Navier-Stokes law is to be modified. Now the final equation may not seem to have a proper general solution, but can be approximated to certain solvable expressions for specific cases of angular velocity.

The Discourse of Impressionism in Beta’s (B. V. Butkevich) Poetics

The article analyzes the impressionistic poetics of Boris Butkevich, a literary figure of the first wave of Russian emigration, a representative of the Harbin literary school. Like most impressionists, the composition of the poetic text by Boris Butkevich lacks a clearly defined beginning and end. The described lyrical situation can theoretically be continued in both directions. The reference points of impressions turn out to be significant, and not their poetic analysis. A similar principle is also found in the author’s prose, which largely repeats and develops the poetics of his lyric poems. Along with repeated melodic tricks in Butkevich’s prose, cross-cutting motives play an important role, passing from one text to another and organizing the unity of the cycle. At the same time, the author maintains the basic principle of impressionistic discourse – the paradoxical inconsistency of the scale of values. The value of an event is determined not by the accuracy of coincidences with the accepted doxes, but by the fact of a random incident of an event in the author’s field of vision.

Memes, genes, and signs: Semiotics in the conceptual interface of evolutionary biology and memetics

In 1976, Richard Dawkins coined the term meme as a way to metaphorically project bio-evolutionary principles upon the processes of cultural and social development. The works of Dawkins and of some other enthusiasts had contributed to a rise in popularity of the concept of memetics (“study of memes”), but the interest to this new field started to decline quite soon. The conceptual apparatus of memetics was based on a number of quasi-biological terms, but the emerging discipline failed to go beyond those initial metaphors. This article is an attempt to rebuild the toolkit of memetics with the help of the more fundamental concepts taken from semiotics and to propose a synthetic conceptual framework connecting genetics and memetics, in which semiotics is used as the transdisciplinary methodology for both disciplines. The concept of sign is used as the meta-lingual equivalent for both the concepts of gene and meme. In the most general understanding, sign is a thing which stands for another thing. In genetics, this translates into gene that is a section of DNA that stands for the algorithm of how a particular biomolecule is built. In memetics, the similar principle works in meme that is a thing that stands for the rules of how a particular cultural practice is performed.

Genome wide analysis in Drosophila reveals diet by gene interactions and uncovers diet-responsive genes

Genetic and environmental factors play a major role in metabolic health. However, they do not act in isolation, as a change in an environmental factor such as diet may exert different effects based on an individual’s genotype. Here, we sought to understand how such gene-diet interactions influenced nutrient storage and utilisation, a major determinant of metabolic disease. We subjected the Drosophila Genetic Reference Panel (DGRP), comprising 200 genetically divergent inbred fly strains, to diets varying in sugar, fat and protein. We assessed starvation resistance, a holistic phenotype of nutrient storage and utilisation that can be robustly measured. Diet influenced the starvation resistance of each strain, but this effect varied markedly between strains. This demonstrates that genetics plays a major role in the response to diet. Furthermore, heritability analysis revealed that the greatest variability arose from diets either high in sugar or high in protein. To uncover the genetic underpinnings of this variation, we mapped 1,239 diet-responsive SNPs in 534 genes, 325 of which have human orthologues. Using whole-body knockdown, we confirmed that 30 candidate genes were required for glucose tolerance, storage and utilization. In particular, we characterised CG4607, a GLUT6/GLUT8 homolog, as a key protein involved in sugar tolerance. Overall, this provides strong evidence that genetics is a major contributor to how individuals respond to diets of varying nutrient composition. It is likely that a similar principle may be applied to metabolic disease in higher organisms thus supporting the case for nutrigenomics as an important health strategy.

Gresham’s Law and News in a Post-Truth World

Economists and finance experts have studied how ‘bad money drives out good’ and formulated Gresham’s law (Mokyr, 2003). The law states that the more expensive money tends to disappear from circulation because it is counterfeited, hoarded, or exported. One can propose a similar principle in the news business – real, verified, and socially relevant news tends to be replaced by fake, unverified, and often socially irrelevant news. This tends to happen not only in the American version of news production models (purportedly neutral and objective) but also in other more ideologically and politically oriented news production models.

The Correlation between Penetration Pressure Required to Install Pile Foundation and to Insert Bi-cones in Cone Penetration Test

One of the common methods used to install pile foundation is hydraulic jacked-in machine. In this method, a pile is pushed down into the ground up to the predetermined depth. The method has similar principle to that of Cone Penetration Test (CPT). This paper presents the correlation between the mobilize pressure required to install pile foundations and that required to push the bi-cones that attached at the tip of CPT rod. The results show that the penetration pressure required to install the pile into very soft clay layer is independent of pile diameter. The penetration pressure required to install the pile into soft to stiff clay layers depends on the pile diameter. The larger the diameter of piles, the smaller the penetration pressures required. The penetration pressure required to install the pile into stiff expansive clay layer beyond the depth of active zone can be predicted as high as the pressure calculated form CPT.

Application of thermal analysis for the evaluation of mineral solution penetration into wood

Interaction of mineral solutions with solid wood leads to saturation of the wood matrix, then to the deposition of mineral particles and eventually to reaction with wood components. In this way a partially or fully mineralized wood occurs in natural or artificial conditions, whose physical-mechanical properties are influenced by the retention and by the character of the solution. Targeted application of organosilanes is based on a similar principle that reduces the intake of liquid water and thus leads to an increase in durability, however, it also causes wood corrosion and consequent decrease in mechanical parameters. In this study, penetration of commercial organosilanes-based product Lukofob 39 into solid wood was described in order to determine the extent of the mineralized part into which the solution penetrated. In this case, characteristic mineral deposits are formed in the wood matrix and its quantification by thermal analysis can be advantageously used to describe the penetration of the solution. Based on the analyses of specific samples taken from primary specimens with different exposure times in the solution, it can be stated that with the increasing exposition time the penetration depth of the solution as well as the amount of mineral deposits increase. The shifts on the thermal analysis curves also show the corrosion effects of Lukofob 39 on the basic components of wood.