scholarly journals New serinolic amino-s-triazines by chemoselective amination of cyanuric chloride and their (pro)diastereomerism in restricted rotational phenomena

2012 ◽  
Vol 10 (4) ◽  
pp. 1119-1136 ◽  
Author(s):  
Oana Moldovan ◽  
Pedro Lameiras ◽  
Eric Henon ◽  
Flavia Popa ◽  
Agathe Martinez ◽  
...  
Keyword(s):  
Building Blocks ◽  
Cyanuric Chloride ◽  
Dynamic Interactions ◽  
Open Chain ◽  
Nmr Data ◽  
Chain Unit ◽  
Closed Chain ◽  
Rotational Equilibrium ◽  
Iterative Synthesis ◽  
Vt Nmr

AbstractThe highly chemoselective preparation of new elaborated N-unsymmetrically substituted chlorodiamino-s-triazines and melamines, seen as building-blocks for iterative synthesis, is reported. It consisted of amination of cyanuric chloride with commercial C-2-substituted 2-aminopropane-1,3-diols (“serinols”), playing the role as “open-chain” unit and enantiopure (1S,2S)-2-amino-1-(4-nitrophenyl)propane-1,3-diols (“p-nitrophenylserinols”) based amino-1,3-dioxanes (“closed-chain” unit). Issued from the restricted rotation about C(s-triazine)-N(exocyclic) partial double bonds, seen as axes of (pro)diastereomerism, a global four-component rotational equilibrium involving the title compounds is discussed based on DFT computation and (VT) NMR data. Depending on π-deficiency of the s-triazine core, an (un)synchronised deblocking of the generated rotational diastereomers was observed. They are discussed as influence of intra-vs. intermolecular NH...OH (dynamic) interactions occurring in the “open-chain” unit and the anancomeric, axial vs. equatorial, amino-anchorage of the “closed-chain” unit.

Design, iterative synthesis and structure of novel optically active trispiro-dendritic melamines incorporating ‘open-chain’ versus ‘closed-chain’ serinolic peripheral units

2015 ◽  
Vol 26 (14) ◽  
pp. 683-701 ◽  
Author(s):  
Oana Moldovan ◽  
Iulia Nagy ◽  
Pedro Lameiras ◽  
Cyril Antheaume ◽  
Carmen Sacalis ◽  
...  
Keyword(s):  
Optically Active ◽  
Open Chain ◽  
Closed Chain ◽  
Iterative Synthesis

scholarly journals Evaluation of Ankle Mobility Loss in Patients Undergoing Subtalar Arthrodesis

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0011
Author(s):  
Tiago S. Baumfeld ◽  
Roberto Zambelli de A. Pinto ◽  
Fernando Araujo S. Lopes ◽  
Daniel Baumfeld ◽  
Camilo Tavares
Keyword(s):  
Range Of Motion ◽  
Plantar Flexion ◽  
Contralateral Side ◽  
Foot And Ankle ◽  
Lower Range ◽  
Open Chain ◽  
Subtalar Arthrodesis ◽  
Closed Chain ◽  
Ankle Mobility ◽  
Dorsal Flexion

Category: Hindfoot Introduction/Purpose: Objective: To evaluate and quantify the loss of ankle mobility in patients undergoing subtalar arthrodesis compared to the contralateral side, through physical examination. Methods: A total of 12 patients who had only the subtalar arthrodesis procedure from various causes in one foot were selected. The same foot and ankle surgeon performed all measurements of bilateral tibiotarsal range of motion, with loaded closed-chain and unloaded open-chain tests. Then, to assess whether there was a difference between the operated and the non-operated side, statistical analysis was performed with the Mann-Whitney test (Hollander and Wolfe 1999). Results: On the loaded closed-chain test, the operated side had a significantly lower range of motion than the contralateral side, with a mean difference of 5.4 degrees for dorsal flexion and 7.6 degrees for plantar flexion. The open-chain tests showed non- significant differences of 3 degrees for dorsal flexion and 5.3 degrees for plantar flexion. Conclusion: Subtalar joint arthrodesis was shown to cause a loss of mobility in the ipsilateral ankle, which is greater in plantar flexion movement.

scholarly journals Identifying Project Corporate Behavioral Risks to Support Long-Term Sustainable Cooperative Partnerships

2021 ◽  
Vol 13 (11) ◽  
pp. 6347
Author(s):  
Marco Nunes ◽  
António Abreu ◽  
Célia Saraiva
Keyword(s):  
Social Network ◽  
Project Management ◽  
Social Network Analysis ◽  
Network Analysis ◽  
Building Blocks ◽  
Research Literature ◽  
Management Tools ◽  
Dynamic Interactions ◽  
Major Factors

Projects are considered crucial building blocks whereby organizations execute and implement their short-, mid-, and long-term strategic visions. Projects are thought, developed, and implemented to solve problems, drive change, satisfy unique needs, add value, and exploit opportunities, just to name a few objectives. Although existing project management tools and techniques aim to deliver projects with success, according to the latest reviewed literature, projects still keep failing at an impressive pace. Among the extensive list of factors that may threaten project success, several articles from the research literature place particular importance on a still underexplored factor that may strongly lead to unsuccessful project delivery. This factor—usually known as corporate behavioral risks—usually emerges and evolves as organizations work together to deliver projects across a bounded period of time, and is characterized by the mix of formal and informal dynamic interactions between the different stakeholders that constitute the different organizations. Furthermore, several articles from the research literature also point out the lack of proper models to efficiently manage corporate behavioral risks as one of the major factors that may lead to projects failing. To efficiently identify and measure how such corporate behaviors may contribute to a project’s outcomes (success or failure), a heuristic model is proposed in this work, developed based on four fundamental fields ((1) project management, (2) risk management, (3) corporate behavior, and (4) social network analysis), to quantitatively analyze four critical project social networks ((1) communication, (2) problem-solving, (3) advice, and (4) trust), by applying the theory of social network analysis (SNA). The proposed model in this work is supported with a case study to illustrate its implementation and application across a project lifecycle, and how organizations can benefit from its application.

scholarly journals Spectra of Local Cluster Flows on Open Chain of Contours

2018 ◽  
Vol 11 (3) ◽  
pp. 628-644 ◽  
Author(s):  
Alexander Pavlovich Buslaev ◽  
Alexander G Tatashev
Keyword(s):  
Dynamical System ◽  
Unit Length ◽  
Self Organization ◽  
Similar System ◽  
Open Chain ◽  
Local Cluster ◽  
Closed Chain

A dynamical system is considered. This dynamical system is a flow of clusters with the same length $l$ on contours of unit length connected into open chain. A similar system such that contours of this system are connected into closed chain was considered earlier. It has been found that, in the case of closed chain of contours, the dynamical system has a spectrum of velocity and mode periodicity consisted of more than one component. In this paper, it has been shown that, in the case of open chain, the spectrum of cluster velocity and mode periodicity contains only one component.The conditions of self-organization and the dependence of cluster velocity on load $l$ is developed.

EXACT GROUND STATES OF ONE-DIMENSIONAL VALENCE-BOND-SOLID HAMILTONIANS

1987 ◽  
Vol 01 (05n06) ◽  
pp. 231-237 ◽  
Author(s):  
P.L. Iske ◽  
W.J. Caspers
Keyword(s):  
Ground State ◽  
Valence Bond ◽  
Ground States ◽  
Open Chain ◽  
State Correlation ◽  
One Dimensional ◽  
Degenerate Ground State ◽  
Closed Chain ◽  
Ground State Correlation ◽  
Valence Bond Solid

The ground state(s) of a Hamiltonian, introduced by Affleck, Kennedy, Lieb and Tasaki, in connection with the Valence-Bond-Solid (VBS) states, are explicitly given for the spin-1 chains. The structure of these ground states is a rather simple one. For a closed chain we find a unique ground state; for the open chain we find a fourfold-degenerate ground state. The ground state correlation function for the ring is calculated.

scholarly journals The Disproportionate Increase of the Intraoperative Flexion and Extension Gap Space after Posterior Cruciate Ligament Resection in Total Knee Arthroplasty

2021 ◽  
Vol 10 (18) ◽  
pp. 4228
Author(s):  
Kao-Chang Tu ◽  
Han-Ting Shih ◽  
Shih-Chieh Tang ◽  
Cheng-Hung Lee ◽  
Wei-Jen Liao ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Posterior Cruciate Ligament ◽  
Knee Arthroplasty ◽  
Cruciate Ligament ◽  
Open Chain ◽  
Flexion Gap ◽  
Closed Chain ◽  
Before And After ◽  
Total Knee ◽  
Extension Gap

Purpose: Maintaining gap balance is critical for total knee arthroplasty (TKA). This study aimed to elucidate if the extension–flexion gaps would be changed with posterior cruciate ligament (PCL) intact (PI) and PCL resection (PR) during TKA. The flexion gaps were measured using two methods, open-(Fo) and closed-chain position (Fc), based on the definition of kinetic chain position, respectively. Methods: This retrospective study enrolled a total of 33 patients who underwent posterior-stabilized (PS) TKA for symptomatic advanced osteoarthritis of knees. After bone cuts were completed, the extension–flexion gaps before and after PCL resection during TKA were measured using a calibrated tensioning device set at a 100 Nm distraction force. To further differentiate the effect of thigh weight on the 90° flexion gap, two varied methods of examination, either in closed chain (Fc) or open chain (Fo) were performed. Results: The increases in the 90° knee flexion gap after PCL resection were measured by both methods, i.e., ΔFc (PR-Fc—PI-Fc): 2.04 ± 2.06 mm, p < 0.001; and mean ΔFo (PR-Fo—PI-Fo): 1.64 ± 1.36 mm, p < 0.001. However, there were no differences between ΔFc and ΔFo before and after PCL resection. A greater amount of flexion gap was identified in open chain than in closed chain after PCL resection, and the PR-Fo and PR-Fc were 14.36 ± 3.13 and 11.40 ± 3.47 (p < 0.001), respectively. Conclusions: The resection of PCL during TKA distinctly increased the flexion gap, but not the extension gap. This disproportionate increase of the gap will cause a gap balance mismatch. The tensioning maneuver in open-chain was more effective to detect the gap differences than in closed-chain before and after PCL resection during TKA.

scholarly journals Comparative Efficacy of Open-chain Kinematics and Closed-chain Kinematics on Walking Proficiency and Societal Integration in Post-stroke Individuals: a Pretest- Post-test Experimental Study

2021 ◽  
Author(s):  
Obianuju Nwaedozie ◽  
Caleb Gbiri ◽  
Olajide Olawale ◽  
Ukamaka Mgbeojedo ◽  
Caleb Adeagbo
Keyword(s):  
Experimental Study ◽  
Bicycle Ergometer ◽  
Stroke Survivors ◽  
Walking Ability ◽  
Open Chain ◽  
Post Stroke ◽  
Gait Parameters ◽  
Closed Chain ◽  
Significant Difference ◽  
Spatio Temporal

Abstract Background Post-stroke hemiplegic gait is a mixture of deviations and compensatory motion dictated by residual function. To improve stroke survivors' walking ability, it is necessary to evaluate different rehabilitation approaches and identify those that have a greater effect on locomotor recovery of stroke patients. Objectives This study was designed to compare the effect of open-chain kinematics (bicycle ergometry) and closed-chain kinematics (treadmill) on walking proficiency in post-stroke individuals and their societal integration. Methods This was a pretest- posttest- experimental study involving 35 ambulatory hemiplegic stroke survivors (18males and 17 females) with a mean age of 53.77±10.95 undergoing rehabilitation at the two Teaching Hospitals in Lagos. Patients went through a 10-week rehabilitation and were randomly assigned to two intervention groups. Spatio-temporal gait parameters were measured by the six-metre walkway and community integrated questionnaire was used to examine home integration, social integration and productive activities. Data were subjected to inferential and descriptive statistics. The level of significance was set at p<0.05. Results Results showed significant difference between baseline and post intervention scores for all the gait parameters in the bicycle ergometer group except for stride length (p = 0.078). There was also a significant difference in the mean change in cadence between the treadmill and bicycle ergometer group (p = 0.04). Conclusions Both open-chain and closed-chain kinematics are effective, but closed- chain is most effective in re-educating ambulation and re-gaining spatio-temporal gait parameters after stroke and should be structured into the patients’ treatment regimen to effectively improve functional capability in post-stroke individuals.

A New Methodology for Robot Controller Design

2005 ◽  
Author(s):  
Jan Peters ◽  
Michael Mistry ◽  
Firdaus Udwadia ◽  
Stefan Schaal
Keyword(s):  
Controller Design ◽  
Nonholonomic Constraints ◽  
Rigid Body Dynamics ◽  
Specific Class ◽  
Open Chain ◽  
Control Laws ◽  
Suggested Approach ◽  
Robot Controller ◽  
Closed Chain ◽  
Gauss Principle

Gauss’ principle of least constraint and its generalizations have provided a useful insights for the development of tracking controllers for mechanical systems [1]. Using this concept, we present a novel methodology for the design of a specific class of robot controllers. With our new framework, we demonstrate that well-known and also several novel nonlinear robot control laws can be derived from this generic framework, and show experimental verifications on a Sarcos Master Arm robot for some of these controllers. We believe that the suggested approach unifies and simplifies the design of optimal nonlinear control laws for robots obeying rigid body dynamics equations, both with or without external constraints, holonomic or nonholonomic constraints, with over-actuation or underactuation, as well as open-chain and closed-chain kinematics.

Dimethylformamide Acetals and Bredereck’s Reagent as Building Blocks in Natural Products Total Synthesis

2020 ◽  
Vol 17 (1) ◽  
pp. 47-66
Author(s):  
Franz Bracher
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Alkylating Agents ◽  
Building Blocks ◽  
Methyl Groups ◽  
Open Chain ◽  
Enol Ethers ◽  
Condensation Products ◽  
Condensation Reactions

Dimethylformamide acetals and Bredereck’s reagent (tert-butoxy-bis(dimethylamino) methane) are versatile C1 building blocks due to their ability to undergo condensation reactions with CH-acidic methyl and methylene moieties. Subsequent modulation of the resulting condensation products enables the preparation of open-chain products like aldehydes, ketones, enones, enol ethers, methyl groups, and, most important in alkaloid total synthesis, the annulation of heterocyclic rings like pyridines, pyridine-N-oxides, bromopyridines, aminopyridines, aminopyrimidines, pyrroles and chromenones. In certain cases, these reagents can act as alkylating agents. The applications of these building blocks in natural products total synthesis are reviewed here.

Sign in / Sign up

Export Citation Format

Share Document