scholarly journals Side Chain Dispersity Matters: Topologically Precise and Discrete Bottlebrush Polymers

2021 ◽  
Author(s):  
Nduka Ogbonna ◽  
Michael Dearman ◽  
Cheng-Ta Cho ◽  
Bhuvnesh Bharti ◽  
Andrew J. Peters ◽  
...  
Keyword(s):  
Structural Heterogeneity ◽  
Thermomechanical Properties ◽  
Side Chain ◽  
Langmuir Blodgett ◽  
Fully Discrete ◽  
Polymer Properties ◽  
Three Phase ◽  
Discrete Structures ◽  
Scalable Synthesis ◽  
The Impact

The synthesis of bottlebrush polymers with topologically precise and fully discrete structures is reported. Key features of the synthesis include the combination of scalable synthesis and separation strategies to access discrete macromonomer libraries, followed by their polymerization and further separation into topologically uniform and discrete bottlebrushes. Discrete macromonomers prove crucial for regulating the structural heterogeneity of bottlebrushes and their macroscopic properties. When assembled as a monolayer at the air-water interface, bottlebrushes with discrete side chains display high packing density and distinct three-phase Langmuir-Blodgett isotherms. The impact of precisely regulating side chain dispersity and sequence on polymer properties was further demonstrated through tailoring the interbrush interactions and thermomechanical properties of well-defined block bottlebrushes.

scholarly journals Synthesis and Biological Activity of Brassinosteroid Analogues with a Nitrogen-Containing Side Chain

2020 ◽  
Vol 22 (1) ◽  
pp. 155
Author(s):  
Mikhail V. Diachkov ◽  
Karoll Ferrer ◽  
Jana Oklestkova ◽  
Lucie Rarova ◽  
Vaclav Bazgier ◽  
...  
Keyword(s):  
Biological Activity ◽  
Functional Groups ◽  
Side Chain ◽  
Biotic And Abiotic Stresses ◽  
Short Side ◽  
Arabidopsis Root ◽  
Physiological Processes ◽  
Growth Promoting ◽  
The Impact ◽  
Brassinosteroid Analogues

Brassinosteroids are a class of plant hormones that regulate a broad range of physiological processes such as plant growth, development and immunity, including the suppression of biotic and abiotic stresses. In this paper, we report the synthesis of new brassinosteroid analogues with a nitrogen-containing side chain and their biological activity on Arabidopis thaliana. Based on molecular docking experiments, two groups of brassinosteroid analogues were prepared with short and long side chains in order to study the impact of side chain length on plants. The derivatives with a short side chain were prepared with amide, amine and ammonium functional groups. The derivatives with a long side chain were synthesized using amide and ammonium functional groups. A total of 25 new brassinosteroid analogues were prepared. All 25 compounds were tested in an Arabidopsis root sensitivity bioassay and cytotoxicity screening. The synthesized substances showed no significant inhibitory activity compared to natural 24-epibrassinolide. In contrast, in low concentration, several compounds (8a, 8b, 8e, 16e, 22a and 22e) showed interesting growth-promoting activity. The cytotoxicity assay showed no toxicity of the prepared compounds on cancer and normal cell lines.

scholarly journals Quadrature Voltage Compensation in the Isolated Multi-Modular Converter

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 529
Author(s):  
Cristian Verdugo ◽  
Jose Ignacio Candela ◽  
Pedro Rodriguez
Keyword(s):  
Control Strategy ◽  
Phase Voltage ◽  
Multilevel Converters ◽  
Photovoltaic Panels ◽  
Circulating Current ◽  
Three Phase ◽  
Voltage Compensation ◽  
Wide Range ◽  
Modular Converter ◽  
The Impact

Series connections of modules in cascaded multilevel converters are prone to power imbalances due to voltage differences on their DC side. When modules are connected to direct current (DC) sources, such as photovoltaic panels, the capability of withstanding power imbalances is crucial for generating the maximum power. In order to provide a possible solution for this requirement, this paper proposes a control strategy called Quadrature Voltage Compensation, which allows a wide range of power imbalances. The proposed control strategy regulates the power by introducing a circulating current between the arms and a phase angle in the output voltage. The impact of the circulating current and its effect on the phase voltage are studied. To highlight the features of the proposed strategy, an analytical model based on vector superposition is also described, demonstrating the strong capability of tolerating power differences. Finally, to validate the effectiveness of the Quadrature Voltage Compensation, simulation and experimental results are presented for a three-phase isolated multi-modular converter.

scholarly journals Reaching consensus on reporting patient and public involvement (PPI) in research: methods and lessons learned from the development of reporting guidelines

BMJ Open ◽  
2017 ◽  
Vol 7 (10) ◽  
pp. e016948 ◽  
Author(s):  
Jo Brett ◽  
Sophie Staniszewska ◽  
Iveta Simera ◽  
Kate Seers ◽  
Carole Mockford ◽  
...  
Keyword(s):  
Public Involvement ◽  
Evidence Base ◽  
Patient And Public Involvement ◽  
Lessons Learned ◽  
Reporting Guidelines ◽  
Consensus Development ◽  
Face To Face ◽  
Three Phase ◽  
Health And Social Care ◽  
The Impact

IntroductionPatient and public involvement (PPI) is inconsistently reported in health and social care research. Improving the quality of how PPI is reported is critical in developing a higher quality evidence base to gain a better insight into the methods and impact of PPI. This paper describes the methods used to develop and gain consensus on guidelines for reporting PPI in research studies (updated version of the Guidance for Reporting Patient and Public Involvement (GRIPP2)).MethodsThere were three key stages in the development of GRIPP2: identification of key items for the guideline from systematic review evidence of the impact of PPI on health research and health services, a three-phase online Delphi survey with a diverse sample of experts in PPI to gain consensus on included items and a face-to-face consensus meeting to finalise and reach definitive agreement on GRIPP2. Challenges and lessons learnt during the development of the reporting guidelines are reported.DiscussionThe process of reaching consensus is vital within the development of guidelines and policy directions, although debate around how best to reach consensus is still needed. This paper discusses the critical stages of consensus development as applied to the development of consensus for GRIPP2 and discusses the benefits and challenges of consensus development.

Regulator Circuit Transformer Voltage-Second Product Analysis

2014 ◽  
Vol 529 ◽  
pp. 501-505
Author(s):  
Chi Zhang ◽  
Ming Zhi He
Keyword(s):  
Power Supply ◽  
Power Electronic ◽  
Product Analysis ◽  
Power Regulator ◽  
Current Voltage ◽  
Three Phase ◽  
The Impact ◽  
Power Electronic Technology ◽  
Primary Current

With the continuous development of power electronic technology, the advantages of thyristor power regulator circuit gradually get more and more applications. It improves the quality of power supply, makes the equipment efficiency and power factor higher and so saves a lot of electricity. Through the calculation of the primary current when thyristor turns off in three-phase power regulator circuit with transformer load, the impact of the thyristors turn-off order on the transformer primary current voltage-second product is analysised, and through simulation the exactness is verified.

scholarly journals Effect of Cold Drawing on Mechanical Properties of Biodegradable Fibers

2017 ◽  
Vol 15 (1) ◽  
pp. 70-76 ◽  
Author(s):  
Francesco Paolo La Mantia ◽  
Manuela Ceraulo ◽  
Maria Chiara Mistretta ◽  
Marco Morreale
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Biodegradable Polymers ◽  
Biodegradable Polymer ◽  
Cold Drawing ◽  
Thermal Characterization ◽  
Systematic Investigation ◽  
Thermomechanical Properties ◽  
Polymer Systems ◽  
The Impact

Purpose Biodegradable polymers are currently gaining importance in several fields, because they allow mitigation of the impact on the environment related to disposal of traditional, nonbiodegradable polymers, as well as reducing the utilization of oil-based sources (when they also come from renewable resources). Fibers made of biodegradable polymers are of particular interest, though, it is not easy to obtain polymer fibers with suitable mechanical properties and to tailor these to the specific application. The main ways to tailor the mechanical properties of a given biodegradable polymer fiber are based on crystallinity and orientation control. However, crystallinity can only marginally be modified during processing, while orientation can be controlled, either during hot drawing or cold stretching. In this paper, a systematic investigation of the influence of cold stretching on the mechanical and thermomechanical properties of fibers prepared from different biodegradable polymer systems was carried out. Methods Rheological and thermal characterization helped in interpreting the orientation mechanisms, also on the basis of the molecular structure of the polymer systems. Results and conclusions It was found that cold drawing strongly improved the elastic modulus, tensile strength and thermomechanical resistance of the fibers, in comparison with hot-spun fibers. The elastic modulus showed higher increment rates in the biodegradable systems upon increasing the draw ratio.

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