Leadless pacing – next generation

2021 ◽  
Vol 4 (57) ◽  
pp. 4-7
Author(s):  
Przemysław Mitkowski

In December 2013 leadless pacing system was implanted in humans for the first time. Both in IDE and PAR re­gistries high effectiveness and safety were confirmed. In the mentioned registries risk of severe complication was reduced by 48 and 63% respectively. The reduced risk was mainly shown in a decreased percentage of hospitali­zations and system revisions. MICRA VR system has activity detectors placed in three planes, which allows to detect onset and end of ventricular contraction as well as early, and atrial contraction related ventricular filling. This property allowed to design an algorithm to detect mechanical atrial contraction. This algorithm caused an increase in atrioventricular synchrony to 80,0 and 94,4% in patients with advanced AV block and preserved conduction, respectively. In patients with advanced AV block percentage of those who reached more than 70% of atrioventricular synchrony was 95%. Parameters which increase the likelihood of high percentage of AV synchrony are standard deviation of consecutive P-P intervals < 5/min. and lower E/A in echocardiography. Practical implementation of a new algorithm required redesigning of a circuit to reduce power consumption. New system MICRA AV was developed, which volume, mass and longevity are comparable with MICRA VR.

2019 ◽  
Author(s):  
Caleb Karmel ◽  
Zhewei Chen ◽  
John Hartwig

We report a new system for the silylation of aryl C-H bonds. The combination of [Ir(cod)(OMe)]<sub>2</sub> and 2,9-Me<sub>2</sub>-phenanthroline (2,9-Me<sub>2</sub>phen) catalyzes the silylation of arenes at lower temperatures and with faster rates than those reported previously, when the hydrogen byproduct is removed, and with high functional group tolerance and regioselectivity. Inhibition of reactions by the H<sub>2</sub> byproduct is shown to limit the silylation of aryl C-H bonds in the presence of the most active catalysts, thereby masking their high activity. Analysis of initial rates uncovered the high reactivity of the catalyst containing the sterically hindered 2,9-Me<sub>2</sub>phen ligand but accompanying rapid inhibition by hydrogen. With this catalyst, under a flow of nitrogen to remove hydrogen, electron-rich arenes, including those containing sensitive functional groups, undergo silylation in high yield for the first time, and arenes that underwent silylation with prior catalysts react over much shorter times with lower catalyst loadings. The synthetic value of this methodology is demonstrated by the preparation of key intermediates in the synthesis of medicinally important compounds in concise sequences comprising silylation and functionalization. Mechanistic studies demonstrate that the cleavage of the aryl C-H bond is reversible and that the higher rates observed with the 2,9-Me<sub>2</sub>phen ligand is due to a more thermodynamically favorable oxidative addition of aryl C-H bonds.


2009 ◽  
Vol 19 (06) ◽  
pp. 1931-1949 ◽  
Author(s):  
QIGUI YANG ◽  
KANGMING ZHANG ◽  
GUANRONG CHEN

In this paper, a modified generalized Lorenz-type system is introduced, which is state-equivalent to a simple and special form, and is parameterized by two parameters useful for chaos turning and system classification. More importantly, based on the parameterized form, two classes of new chaotic attractors are found for the first time in the literature, which are similar but nonequivalent in topological structure. To further understand the complex dynamics of the new system, some basic properties such as Lyapunov exponents, Hopf bifurcations and compound structure of the attractors are analyzed and demonstrated with careful numerical simulations.


Kavkaz-forum ◽  
2021 ◽  
pp. 90-100
Author(s):  
Ф.С. Киреев

В статье анализируются причины возвращения войсковой системы самоуправления Терского казачества и показан сам процесс создания выборности войсковой власти. Актуальность исследования казачьего самоуправления обусловлена необходимостью теоретического обоснования и практического осуществления самоорганизации казачества России. Исторический анализ процесса организации самоуправления Терского казачества на войсковом уровне может послужить фундаментом для лучшего понимания и оценки современных процессов и явлений в казачьей среде и поможет выстраиванию государственной политики в отношении казачества в современной России. В отечественной историографии отсутствуют работы, посвященные конкретно восстановлению выборности власти в Терском казачьем войске. Поэтому научная новизна исследования определяется тем, что впервые предпринята попытка хронологической реконструкции истории создания войсковой системы самоуправления Терского казачества. Методологической основой исследования является принцип историзма, что предусматривает изучение момента возникновения исторического события и этапы его развития. Анализ событий на Тереке в 1917 г. показывает, что терские казаки смогли самоорганизоваться, создать полноценное административно-территориальное образование, и лишь изменение социально-политической ситуации в России в целомпомешало укрепить и продолжить это начинание. Еще необходимо отметить, что терские казаки к моменту восстановления войскового самоуправления подошли уже с готовыми проектами соответствующих документов, что позволило Терскому войску первым среди других войск создать свою выборную власть. Это говорит о высоком интеллектуальном потенциале в среде терских казаков. The article analyzes the reasons for the restoration of the military system of self-government of the Terek Cossacks and shows the very process of creating the elective military power. The relevance of the study of Cossack self-government is due to the need for theoretical justification and practical implementation of the self-organization of the Cossacks of Russia. Historical analysis of the process of organizing self-government of the Terek Cossacks at the military level can serve as a foundation for better understanding and assessment of modern processes and phenomena in the Cossack environment and will help to build state policy towards the Cossacks in modern Russia. In the Russian historiography, there are no works devoted specifically to the restoration of the election of power in the Terek Cossack army. Therefore, the scientific novelty of the research is determined by the fact that for the first time an attempt was made to chronologically reconstruct the history of the creation of the military system of self-government of the Terek Cossacks. The methodological basis of the research is the principle of historicism, with its focus on the study of the moment of occurrence of a historical event and the stages of its development. An analysis of the events on the Terek in 1917 shows that the Terek Cossacks were able to organize themselves and create a full-fledged administrative-territorial entity and only a change in the socio-political situation in Russia as a whole was placed, strengthened and continued this initiative. It should also be noted that the Terek Cossacks, by the time of the restoration of military self-government, came up with ready-made drafts of relevant documents, which allowed the Terek army to be the first among other troops to create their own elected power. This indicates a high intellectual potential among the Terek cossacks.


Author(s):  
Sebastian Röhl

AbstractBased on a comprehensive literature review of student feedback intervention studies in schools, this chapter provides an overview of found effects on teachers and teaching. The first part summarizes the self-reported cognitive, affective, and motivational effects of student feedback on teachers, which can subsequently lead to behavioral changes in the classroom. In the second part, the focus is on the extent to which these behavioral changes are perceived by students. For the first time, a meta-analysis of changes in students’ perceptions of teaching was carried out for the 18 existing longitudinal studies for this purpose. A small but significant positive weighted mean effect size of d=0.21 for students’ perceived improvement of teaching quality was found, while more in-depth analyses pointed to a beneficial effect of individual support measures for teachers regarding reflection and subsequent development of teaching. Implications for further research and practical implementation of student feedback in schools are discussed.


2015 ◽  
Vol 6 (37) ◽  
pp. 6709-6719 ◽  
Author(s):  
Hong Yang ◽  
You-Jing Lv ◽  
Ming Xu ◽  
Jun Wang ◽  
Bao-Ping Lin ◽  
...  

This work describes a new system of MJLCPs with poly(vinyl benzoate)-backbone, which are efficiently synthesized by the bulk photo-polymerization method. Furthermore, homogeneous- or homeotropic-aligned cross-linked MJLCP (xMJLCP) films are for the first time successfully prepared.


1969 ◽  
Vol 77 (6) ◽  
pp. 784-791 ◽  
Author(s):  
Stanton P. Nolan ◽  
Sewell H. Dixon ◽  
R.Darryl Fisher ◽  
Andrew G. Morrow

1988 ◽  
Vol 61 (13) ◽  
pp. 1135-1136 ◽  
Author(s):  
Ted M. Parris ◽  
Gary S. Mintz ◽  
John Ross ◽  
Ioannis P. Panidis

2006 ◽  
Vol 16 (09) ◽  
pp. 2559-2574 ◽  
Author(s):  
CHRISTINA RUBILLO ◽  
PIERGIOVANNI MARZOCCA ◽  
ERIK BOLLT

In this paper we present, the design and modeling of the novel nonlinear limiter control feedback control plant [Myneni et al., 1999; Corron et al., 2000; Corron & Pethel, 2002], applied for the first time here in an aeroelastic system, and actuated as a jet reaction torquer control of a wing with potentially chaotic dynamics. This study will provide a better understanding of the nonlinear dynamics of the open/closed-loop aeroelasticity of flexible wings with either steady or unsteady aerodynamic loads. The limiter control can be applied to either the plunging or pitching characteristic of the wing or to both of them. We show that the control can effectively suppress Limit Cycle Oscillations (LCO) and chaos well beyond the nominal flutter speed. This could lead to a practical implementation of the control mechanism on actual and future generation aircraft wings via implementation of a combination of propulsive/jet type forces, micro surface effectors and fluidic devices. Analysis of this control produced favorable results in the suppression of LCO amplitude and increased flutter boundaries for plunging and pitching motion. The limiting control has asymptotically zero power, and is simply implemented, making it a feasible solution to the problem of the chaotic dynamics of the oscillating airfoil.


2021 ◽  
Vol 12 (2) ◽  
pp. 189-200
Author(s):  
Nadiia Brit ◽  
Olha Sushkevych ◽  
Aliona Solodchuk ◽  
Nataliia Shulga

The article focuses on the project method as a teaching tool, which activates teacher and students’ roles in learning English. We reveal our experience of implementing project activities to develop different communicative skills such as speaking, reading, listening, and writing. The paper deals with special approaches while developing project stages for each skill. In the article, listening skills are presented as the most difficult ones for the students to acquire within the project method activity. Even the most advanced learners need to prolong working on listening and will find that there are some words or collocations which are difficult to understand the first time they hear them. It can be stated that project method implementation into class activities comprises all language skills which are interconnected, meanwhile, reading skills are the basis of writing activity and enlarge an individual’s vocabulary, knowledge about the world around or inner outlook. Listening skills prepare for better understanding, responding and proceed to further information in the process of learning. It is also emphasized that development of speaking skills with the project method provide easier communication for a speaker in different speech areas, which can lead to the higher professional development.


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