conductive system
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Author(s):  
O. V. Grechana ◽  
A. H. Serbin ◽  
A. M. Rudnyk ◽  
O. O. Salii

The world plant products market is expanded rapidly and trade in them tends to grow by 15–25 % annually. The number of reports is increased proportionally about accidental contamination or deliberate, economically motivated falsification of plant raw materials. 27 % of the nearly 6.000 herbal preparations that are sold in 37 countries have contained undeclared contaminants, substitutes, or other components, according to the literature. We have conducted a plant conduction system microscopic analysis of the individual members’ genus Clover (Trifoliae L.), Fabaceae L. to identify morphoanatomical characteristics. Clover has anti-inflammatory, antiseptic, choleretic, diaphoretic, diuretic, hemostatic, expectorant, astringent properties and is used in many diseases. Aim. The finding common features and those that differ and can be used as diagnostic during studying the conducting system structure of genus Trifolium L. leaves and stems. Materials and methods. Plant material (herb) from Trifolium pratense L., T. incarnatum L., T. repens L. and T. fragiferum L. was harvested during the active flowering period – (May – June) and was dried in a well-ventilated place. Leaves and stems preparations were pre-boiled in 5 % sodium hydroxide water solution and fixed in chloral hydrate solution. Cross-sections were made with a microtome. The BIOLAM LOMO light microscope (Russia) and OLYMPUS SH-21 digital camera were used to record the data about identify the conducting apparatus of the plant’s leaf, petiole, and stem. Results. It has been examined the central vein structure of T. pratense L. and T. fragiferum L. leaves, it was determined that the conductive system is covered with a crystalline coating and there is one closed collateral bundle in the center, which is not typical for dicotyledonous plants. The petioles of T. incarnatum L., T. fragiferum L., and T. repens L. in cross-section are several different shapes. There are kidney-shaped and round. The conducting apparatus T. incarnatum L. and T. repens L. have arranged in a circle, closed and collateral. The leafstalk structure type of T. fragiferum L. is bunchles. It contradicts too the information about the structure conducting system of dicotyledonous plants. The stem’s conducting bundles are collateral and open. Conclusions. We have paid attention to the structural peculiarities of the conductive system of the central vein and petiole of objects for study: Trifolium pratense L., T. incarnatum L., T. repens L., and T. fragiferum L. when searching for differentiating features in some members of the genus Trifoliae L. in pharmacognostic analysis. The Dicotyledonae representatives are not characteristic of the closed type of conductive bundles, which we observed during microscopic examination.


Heart Rhythm ◽  
2021 ◽  
Vol 18 (8) ◽  
pp. S296-S297
Author(s):  
Skylar Buchan ◽  
Allison Post ◽  
Mathews M. John ◽  
Gabriel Rodriguez-Rivera ◽  
Elizabeth Cosgriff-Hernandez ◽  
...  
Keyword(s):  

Author(s):  
V. Y Ulyanov

Purpose. The purpose of the work is to identify the ways to increase the efficiency of engineering research, based on the significant amount of exploration work required in the creation of modern man-made objects, taking into account the shortcomings of existing instruments and equipment used to measure soil stress, and in relation to the need to improve the design of thermopressiometers, which are aimed to facilitate the study of frozen soils. Methodology. The ways to improve the blade thermopressiometer for the study of frozen soils with different aggregates were selected by the comparative-analytical method and the method of analogy. Thawing depth, absolute soil sediment, deformation modulus etc. were determined by thermal-technical calculations. Findings. The application issues of concern of the existing thermopressiometers (limited research of soils of a certain type, complexity and insufficient accuracy of readings) identified can be overcome by the proposed improved design of a blade thermopressiometer for testing frozen sandy-clay soils. It is based on the improved heating circuit, the applicationd of quality materials and changing the form of the blades and body. The device is intented for use on permafrost and natural frozen soils of the world, including Ukraine. Originality. For the first time we offered a model of an advanced thermopressiometer with an improved body shape made of high-quality corrosion-resistant materials, including non-metallic ones. It has the reduced number of blades to one retractable sector blade-stamp (square or round) and one heating blade-stamp. A special probe design with mechanical/hydraulical sensor drive with a thermocouple (or with two fork probes to improve the measurements) was proposed. It was also recommended to introduce an electric conductive system designed for thawed soils, with a rod for measuring the retractable blade-stamp. The possibility of using a thermopressiometer during the study of seasonally frozen soils is established. Practical value. Improving the device model should facilitate its application in engineering and geological research for various types of construction, including transport, hydraulic engineering, which use the methods of deep freezing of weak and unstable soils.


2021 ◽  
Author(s):  
Sita Shrestha ◽  
Bishnu Kumar Shrestha ◽  
Oh Kwang Joong ◽  
Chan Hee Park ◽  
Cheol Sang Kim

Surface functionalized protonated emeraldine salt (PES) synthesized at 0.18 V provide robust electrically conductive system with low surface resistivity (81.18 mΩ). The PES show ability of cell-type specific microenvironment supporting PC12 cells for neural differentiation.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Jing Huang ◽  
Qing Wan ◽  
Yu Zou ◽  
Lijie Wang ◽  
Yesheng Pan

Abstract Background Familial dilated cardiomyopathy (FDCM) is most commonly inherited as an autosomal dominant trait. The Lamin A/C (LMNA) gene variants have been identified to be associated with DCM, conductive system disorders, type 2 Emery-Dreifuss muscular dystrophy and several other disorders. Here, we reported a novel variant in the LMNA gene that might be related to FDCM. Case presentation A 30-year-old young man was hospitalized for chest tightness, extreme fatigue, palpitation and impaired activity tolerance. He had clinical characteristics including cardiac dilatation, atrial tachyarrhythmia, severe conductive system disorders, and dyskinesia of both upper limbs and the neck. Genetic sequence analysis indicated that the patient carried a novel c.1325 T>C heterozygous LMNA gene variant. Catheter ablation and cardiac resynchronization therapy with pacing function (CRT-P) were performed to treat the arrhythmia. Conclusion The variant c.1325 T>C is a novel variant in the LMNA gene that has not been previously reported. Young patients with DCM, conductive system disorders and skeletal myopathy should be alert to the possibility of LMNA gene variant. Cardiac resynchronization therapy (CRT) may be a reasonable choice for patient carrying a LMNA gene variant with third-degree atrioventricular block even if the left ventricular ejection fraction is preserved in order to prevent the deterioration of cardiac function caused by right ventricular pacing dependency.


2020 ◽  
pp. 116-119
Author(s):  
Вячеслав Иосифович Иванченко ◽  
Дмитрий Валериевич Потанин ◽  
Антон Юрьевич Зотиков ◽  
Пётр Пантелеевич Радчевский

В статье описывается новый анатомический метод изучения проводящей системы привоя и подвоя винограда. Дается сравнительная оценка подвойным, привойным черенкам и саженцам винограда на основе значений удельной водопроводимости тканей древесины. Установлено превалирование проводящей системы подвойных сортов над привойными сортами и саженцами винограда. Показана зональность поперечного сечения с большей функциональной активностью проводящих сосудов. Установлена тенденция в зависимости значений удельной водопроводимости тканей древесины и таких сортовых признаков подвоев как сила роста и карбонатоустойчивость. Определена взаимосвязь между показателями развития тканей подвойных, привойных сортов и саженцев винограда, удельной водопроводимостью тканей древесины. The article describes new anatomical method of study of the conductive system of scion and rootstock of grapes. A comparative assessment was given for rootstock, scion and grape seedlings based on the values of the specific water transmissibility of xylem tissues. The predominance of the conductive system of rootstock varieties over scion varieties and grape seedlings was established. Zonal distribution of the cross-section with greater functional activity of conductive vessels was shown. Dependence of values of the specific water transmissibility of xylem tissues on such varietal characteristics of rootstocks as strength of growth and carbon stability was established. The relationship between the parameters of development of rootstock, scion and seedling tissues and the specific water transmissibility of xylem tissues was determined.


2020 ◽  
Author(s):  
Sara Bonetti ◽  
Daniel Breitenstein ◽  
Simone Fatichi ◽  
Jean-Christophe Domec ◽  
Dani Or

<p>The xylem specific hydraulic conductivity (k<sub>s</sub>) is a key trait for the description of the plant’s ability to sustain the long-distance water transport required for transpiration. In this work, we systematically analyze xylem flow in several woody plants with contrasting anatomical traits combining flow experiments under different hydraulic pressure gradients. Results show a time and pressure dependence of k<sub>s</sub> similar to observations made a century ago by Dixon (1914). We mainly attribute the persistent drop in k<sub>s</sub>, accentuated with higher-pressure gradients, to a wounding response of the xylem tissues. Evidence suggests that wounded xylem tissue releases polysaccharides (prominently pectin) that gradually occlude xylem conduits. The macroscopic definition of K is further affected by complex microscopic xylem dynamics, with a key role of the xylem network topology, interconduit pit membrane flexibility, and redundancy of flow paths. These findings validate the picture of a complex and delicate conductive system whose hydraulic behavior goes beyond that of passive and inert deadwood. Notable implications for xylem conceptualization, measurements protocols, as well as ecosystem modeling applications are discussed.</p>


2020 ◽  
Vol 4 (1) ◽  

This publication discusses models that describe the heart tissue as an active conductive system, taking into account its self-oscillating properties. In this type of models, cardiac rhythms can be described on the basis of the theory of dynamic systems, which justifies the need to build a universal model of oscillating medium. This type of model contributes to the understanding of these pathologies cardiac activity as parasecoli and AB-blockade.


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