SG1 Nitroxide Analogues: a Comparative Study

2010 ◽  
Vol 63 (8) ◽  
pp. 1237 ◽  
Author(s):  
Jessica Marchand ◽  
Laurent Autissier ◽  
Yohann Guillaneuf ◽  
Jean-Luc Couturier ◽  
Didier Gigmes ◽  
...  
Keyword(s):  
Butyl Acrylate ◽  
Life Time ◽  
Good Alternative ◽  
Styrene Polymerization ◽  
Butyl Group ◽  
Tert Butyl Group ◽  
Slow Kinetics ◽  
The One ◽  
And Control ◽  
Nitroxide Mediated Polymerization

Due to a specific balance between steric, polar, and stabilization effects, SG1 nitroxide and its corresponding alkoxyamine BlocBuilder MA are now well recognized as two of the most potent compounds in nitroxide-mediated polymerization (NMP). In this work, alternatives to SG1, based on various aldehydes, were targeted using structure–reactivity relationships already developed by our group. Compared with SG1, we show that the substitution of the tert-butyl group on the carbon α to the aminoxyl function by a 2-ethylhexyl group led to a new nitroxide (ETHEXNO), which exhibited an half-life time at 120°C similar to SG1 and a slightly slower kd for the alkoxyamine (2–3 times lower than the SG1). The styrene polymerization mediated by the ETHEXNO nitroxide has a similar behaviour to the one mediated by the SG1 in terms of livingness and control but the kinetics is affected (2–3 times lower). Concerning the n-butyl acrylate polymerization, an unexpected overheating occurred at 120°C, which led us to perform the polymerization in toluene at 100°C. The slow kinetics impedes the use of this nitroxide as a good alternative to SG1 and shows that the structure of the SG1 nitroxide is already delicately optimized and finding good alternatives is not straightforward.

An LQ Approach to Active Control of Vibrations in Helicopters

1996 ◽  
Vol 118 (3) ◽  
pp. 482-488 ◽  
Author(s):  
Sergio Bittanti ◽  
Fabrizio Lorito ◽  
Silvia Strada
Keyword(s):  
Optimal Control ◽  
Active Control ◽  
Linear Quadratic ◽  
Control Effort ◽  
Vibration Effect ◽  
Suitable Definition ◽  
Lq Optimal Control ◽  
The One ◽  
Definition Of ◽  
And Control

In this paper, Linear Quadratic (LQ) optimal control concepts are applied for the active control of vibrations in helicopters. The study is based on an identified dynamic model of the rotor. The vibration effect is captured by suitably augmenting the state vector of the rotor model. Then, Kalman filtering concepts can be used to obtain a real-time estimate of the vibration, which is then fed back to form a suitable compensation signal. This design rationale is derived here starting from a rigorous problem position in an optimal control context. Among other things, this calls for a suitable definition of the performance index, of nonstandard type. The application of these ideas to a test helicopter, by means of computer simulations, shows good performances both in terms of disturbance rejection effectiveness and control effort limitation. The performance of the obtained controller is compared with the one achievable by the so called Higher Harmonic Control (HHC) approach, well known within the helicopter community.

scholarly journals Structural comparison of CD163 SRCR5 from different species sheds some light on its involvement in porcine reproductive and respiratory syndrome virus-2 infection in vitro

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Hongfang Ma ◽  
Rui Li ◽  
Longguang Jiang ◽  
Songlin Qiao ◽  
Xin-xin Chen ◽  
...  
Keyword(s):  
Scavenger Receptor ◽  
Host Cells ◽  
Respiratory Syndrome Virus ◽  
Swine Industry ◽  
Prrs Virus ◽  
Rich Domain ◽  
Serious Disease ◽  
The One ◽  
And Control

AbstractPorcine reproductive and respiratory syndrome (PRRS) is a serious disease burdening global swine industry. Infection by its etiological agent, PRRS virus (PRRSV), shows a highly restricted tropism of host cells and has been demonstrated to be mediated by an essential scavenger receptor (SR) CD163. CD163 fifth SR cysteine-rich domain (SRCR5) is further proven to play a crucial role during viral infection. Despite intense research, the involvement of CD163 SRCR5 in PRRSV infection remains to be elucidated. In the current study, we prepared recombinant monkey CD163 (moCD163) SRCR5 and human CD163-like homolog (hCD163L1) SRCR8, and determined their crystal structures. After comparison with the previously reported crystal structure of porcine CD163 (pCD163) SRCR5, these structures showed almost identical structural folds but significantly different surface electrostatic potentials. Based on these differences, we carried out mutational research to identify that the charged residue at position 534 in association with the one at position 561 were important for PRRSV-2 infection in vitro. Altogether the current work sheds some light on CD163-mediated PRRSV-2 infection and deepens our understanding of the viral pathogenesis, which will provide clues for prevention and control of PRRS.

Tolerance and Control. Developing a language policy for an EMI university in Uzbekistan

2020 ◽  
Vol 34 (1) ◽  
pp. 217-237
Author(s):  
Andrew Linn ◽  
Anastasiya Bezborodova ◽  
Saida Radjabzade
Keyword(s):  
Higher Education ◽  
Language Policy ◽  
Control Measures ◽  
The Other ◽  
Language Policies ◽  
Language Ecology ◽  
English Only ◽  
English Medium Instruction ◽  
The One ◽  
And Control

AbstractThis article presents a practical project to develop a language policy for an English-Medium-Instruction university in Uzbekistan. Although the university is de facto English-only, it presents a complex language ecology, which in turn has led to confusion and disagreement about language use on campus. The project team investigated the experience, views and attitudes of over a thousand people, including faculty, students, administrative and maintenance staff, in order to arrive at a proposed policy which would serve the whole community, based on the principle of tolerance and pragmatism. After outlining the relevant language and educational context and setting out the methods and approach of the underpinning research project, the article goes on to present the key findings. One of the striking findings was an appetite for control and regulation of language behaviours. Language policies in Higher Education invariably fall down at the implementation stage because of a lack of will to follow through on their principles and their specific guidelines. Language policy in international business on the other hand is characterised by a control stage invariably lacking in language planning in education. Uzbekistan is a polity used to control measures following from policy implementation. The article concludes by suggesting that Higher Education in Central Asia may stand a better chance of seeing through language policies around English-Medium Instruction than, for example, in northern Europe, based on the tension between tolerance on the one hand and control on the other.

scholarly journals Practices of sustainability and the enactment of their natures/cultures: Ecosystem services, rights of nature, and geoengineering

2021 ◽  
pp. 053901842199894
Author(s):  
Frank Adloff ◽  
Iris Hilbrich
Keyword(s):  
Ecosystem Services ◽  
Latin American ◽  
Social Systems ◽  
The Earth ◽  
Starting Point ◽  
Knowledge Cultures ◽  
Rights Of Nature ◽  
Value Of Nature ◽  
The One ◽  
And Control

Possible trajectories of sustainability are based on different concepts of nature. The article starts out from three trajectories of sustainability (modernization, transformation and control) and reconstructs one characteristic practice for each path with its specific conceptions of nature. The notion that nature provides human societies with relevant ecosystem services is typical of the path of modernization. Nature is reified and monetarized here, with regard to its utility for human societies. Practices of transformation, in contrast, emphasize the intrinsic ethical value of nature. This becomes particularly apparent in discourses on the rights of nature, whose starting point can be found in Latin American indigenous discourses, among others. Control practices such as geoengineering are based on earth-systemic conceptions of nature, in which no distinction is made between natural and social systems. The aim is to control the earth system as a whole in order for human societies to remain viable. Practices of sustainability thus show different ontological understandings of nature (dualistic or monistic) on the one hand and (implicit) ethics and sacralizations (anthropocentric or biocentric) on the other. The three reconstructed natures/cultures have different ontological and ethical affinities and conflict with each other. They are linked to very different knowledge cultures and life-worlds, which answer very differently to the question of what is of value in a society and in nature and how these values ought to be protected.

scholarly journals Analysis of Risk Factors in Dementia Through Machine Learning

2020 ◽  
pp. 1-17
Author(s):  
Francisco Javier Balea-Fernandez ◽  
Beatriz Martinez-Vega ◽  
Samuel Ortega ◽  
Himar Fabelo ◽  
Raquel Leon ◽  
...  
Keyword(s):  
Machine Learning ◽  
Optimization Algorithms ◽  
Progressive Increase ◽  
Control Group ◽  
Data Sets ◽  
Modifiable Factors ◽  
Validation Set ◽  
The One ◽  
And Control ◽  
Potential Tool

Background: Sociodemographic data indicate the progressive increase in life expectancy and the prevalence of Alzheimer’s disease (AD). AD is raised as one of the greatest public health problems. Its etiology is twofold: on the one hand, non-modifiable factors and on the other, modifiable. Objective: This study aims to develop a processing framework based on machine learning (ML) and optimization algorithms to study sociodemographic, clinical, and analytical variables, selecting the best combination among them for an accurate discrimination between controls and subjects with major neurocognitive disorder (MNCD). Methods: This research is based on an observational-analytical design. Two research groups were established: MNCD group (n = 46) and control group (n = 38). ML and optimization algorithms were employed to automatically diagnose MNCD. Results: Twelve out of 37 variables were identified in the validation set as the most relevant for MNCD diagnosis. Sensitivity of 100%and specificity of 71%were achieved using a Random Forest classifier. Conclusion: ML is a potential tool for automatic prediction of MNCD which can be applied to relatively small preclinical and clinical data sets. These results can be interpreted to support the influence of the environment on the development of AD.

School-based obesity interventions in the metropolitan area of Rio De Janeiro, Brazil: pooled analysis from five randomised studies

2021 ◽  
pp. 1-7
Author(s):  
Renata da R. M. Rodrigues ◽  
Bruna K. Hassan ◽  
Michele R. Sgambato ◽  
Bárbara da S. N. Souza ◽  
Diana B. Cunha ◽  
...  
Keyword(s):  
Eating Habits ◽  
Intervention Group ◽  
Pooled Analysis ◽  
Control Group ◽  
Intention To Treat ◽  
School Year ◽  
School Based ◽  
Obesity Interventions ◽  
The One ◽  
And Control

Abstract School-based studies, despite the large number of studies conducted, have reported inconclusive results on obesity prevention. The sample size is a major constraint in such studies by requiring large samples. This pooled analysis overcomes this problem by analysing 5926 students (mean age 11·5 years) from five randomised school-based interventions. These studies focused on encouraging students to change their drinking and eating habits, and physical activities over the one school year, with monthly 1-h sessions in the classroom; culinary class aimed at developing cooking skills to increase healthy eating and attempts to family engagement. Pooled intention-to-treat analysis using linear mixed models accounted for school clusters. Control and intervention groups were balanced at baseline. The overall result was a non-significant change in BMI after one school year of positive changes in behaviours associated with obesity. Estimated mean BMI changed from 19·02 to 19·22 kg/m2 in the control group and from 19·08 to 19·32 kg/m2 in the intervention group (P value of change over time = 0·09). Subgroup analyses among those overweight or with obesity at baseline also did not show differences between intervention and control groups. The percentage of fat measured by bioimpedance indicated a small reduction in the control compared with intervention (P = 0·05). This large pooled analysis showed no effect on obesity measures, although promising results were observed about modifying behaviours associated with obesity.

scholarly journals Observation and control of the weak topological insulator state in ZrTe5

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Peng Zhang ◽  
Ryo Noguchi ◽  
Kenta Kuroda ◽  
Chun Lin ◽  
Kaishu Kawaguchi ◽  
...  
Keyword(s):  
Band Gap ◽  
Topological Insulator ◽  
Spin Current ◽  
Side Surface ◽  
Quantum Spin ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Dirac Semimetal ◽  
Topological States ◽  
The One ◽  
And Control

AbstractA quantum spin Hall (QSH) insulator hosts topological states at the one-dimensional (1D) edge, along which backscattering by nonmagnetic impurities is strictly prohibited. Its 3D analogue, a weak topological insulator (WTI), possesses similar quasi-1D topological states confined at side surfaces. The enhanced confinement could provide a route for dissipationless current and better advantages for applications relative to strong topological insulators (STIs). However, the topological side surface is usually not cleavable and is thus hard to observe. Here, we visualize the topological states of the WTI candidate ZrTe5 by spin and angle-resolved photoemission spectroscopy (ARPES): a quasi-1D band with spin-momentum locking was revealed on the side surface. We further demonstrate that the bulk band gap is controlled by external strain, realizing a more stable WTI state or an ideal Dirac semimetal (DS) state. The highly directional spin-current and the tunable band gap in ZrTe5 will provide an excellent platform for applications.

scholarly journals Is There a Predisposition towards the Use of New Technologies within the Traffic Field of Emerging Countries? The Case of the Dominican Republic

Electronics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1208
Author(s):  
Francisco Alonso ◽  
Mireia Faus ◽  
Cristina Esteban ◽  
Sergio A. Useche
Keyword(s):  
Dominican Republic ◽  
Road Safety ◽  
New Technologies ◽  
Technological Development ◽  
Personal Data ◽  
Emerging Countries ◽  
Level Of Knowledge ◽  
One Year ◽  
The One ◽  
And Control

Technological devices are becoming more and more integrated in the management and control of traffic in big cities. The population perceives the benefits provided by these systems, and, therefore, citizens usually have a favorable opinion of them. However, emerging countries, which have fewer available infrastructures, could present a certain lack of trust. The objective of this work is to detect the level of knowledge and predisposition towards the use of new technologies in the transportation field of the Dominican Republic. For this study, the National Survey on Mobility was administered to a sample of Dominican citizens, proportional to the ONE census and to sex, age and province. The knowledge of ITS topics, as well as the use of mobile applications for mobility, are scarce; however, there was a significant increase that can be observed in only one year. Moreover, technology is, in general, positively assessed for what concerns the improvement of the traffic field, even though there is a lack of predisposition to provide one’s personal data, which is necessary for these devices. The process of technological development in the country must be backed up by laws that protect the citizens’ privacy. Thus, technologies that can improve road safety, mobility and sustainability can be implemented in the country.

scholarly journals Agro-Environmental Determinants of Leptospirosis: A Retrospective Spatiotemporal Analysis (2004−2014) in Mahasarakham Province (Thailand)

2021 ◽  
Vol 6 (3) ◽  
pp. 115
Author(s):  
Jaruwan Viroj ◽  
Julien Claude ◽  
Claire Lajaunie ◽  
Julien Cappelle ◽  
Anamika Kritiyakan ◽  
...  
Keyword(s):  
Public Health ◽  
Animal Health ◽  
Spatiotemporal Analysis ◽  
Health Concern ◽  
Intersectoral Collaboration ◽  
The Public ◽  
Additive Modeling ◽  
The One ◽  
And Control ◽  
Northeastern Thailand

Leptospirosis has been recognized as a major public health concern in Thailand following dramatic outbreaks. We analyzed human leptospirosis incidence between 2004 and 2014 in Mahasarakham province, Northeastern Thailand, in order to identify the agronomical and environmental factors likely to explain incidence at the level of 133 sub-districts and 1,982 villages of the province. We performed general additive modeling (GAM) in order to take the spatial-temporal epidemiological dynamics into account. The results of GAM analyses showed that the average slope, population size, pig density, cow density and flood cover were significantly associated with leptospirosis occurrence in a district. Our results stress the importance of livestock favoring leptospirosis transmission to humans and suggest that prevention and control of leptospirosis need strong intersectoral collaboration between the public health, the livestock department and local communities. More specifically, such collaboration should integrate leptospirosis surveillance in both public and animal health for a better control of diseases in livestock while promoting public health prevention as encouraged by the One Health approach.

scholarly journals Synthesis of poly (n-butyl acrylate) with tempo by nitroxide mediated polymerization method

2021 ◽  
pp. 096739112110245
Author(s):  
Amrita Sharma ◽  
PP Pande
Keyword(s):  
Butyl Acrylate ◽  
Low Cost ◽  
Polymerization Process ◽  
Polymerization Reaction ◽  
High Concentration ◽  
Acrylate Monomer ◽  
Controlled Polymerization ◽  
Acrylate Monomers ◽  
Nitroxide Mediated Polymerization ◽  
Polymerization Method

It has been observed that acrylate monomers are very difficult to polymerize with the low cost nitroxide catalyst 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO). Therefore, costly acyclic nitroxides such as N-tert-butyl-N-(1-diethylphosphono-2,2-dimethyl)-N-oxyl, (SG1), 2,2,5-Trimethyl-4-phenyl-3-azahexane-3-nitroxide (TIPNO) and TIPNO derivatives have to be used for the polymerization of the acrylic acid derivatives. There are very few reports on the use of TEMPO-derivatives toward the polymerization of n-butyl acrylate. Generally different reducing agents viz. glucose, ascorbic acid, hydroxyacetone etc. have been used to destroy excess TEMPO during the polymerization reaction. The acrylate polymerizations fail in the presence of TEMPO due to the strong C–O bond formed between the acrylate chain end and nitroxide. To the best of our knowledge, no literature report is available on the use of TEMPO without reducing agent or high temperature initiators, toward the polymerization of n-butyl acrylate. The present study has been carried out with a view to re-examine the application of low cost nitroxide TEMPO, so that it can be utilized towards the polymerization of acrylate monomers (e.g. n-butyl acrylate). We have been able to polymerize n-butyl acrylate using the nitroxide TEMPO as initiator (via a macroinitiator). In this synthesis, a polystyrene macroinitiator was synthesized in the first step from TEMPO, after this TEMPO end-capped styrene macroinitiator (PSt-TEMPO) is used to polymerize n-butyl acrylate monomer. The amount of macroinitiator taken was varied from 0.05% to 50% by weight of n-butyl acrylate monomer. The polymerization was carried out at 120°C by bulk polymerization method. The experimental findings showed a gradual increase in molecular weight of the polymer formed and decrease in the polydispersity index (PDI) with increase in amount of PSt-TEMPO macroinitiator taken. In all experiments conversion was more than 80%. These results indicate that the polymerization takes place through controlled polymerization process. Effect of different solvents on polymerization has also been investigated. In the following experiments TEMPO capped styrene has been used as macroinitiator leading to the successful synthesis of poly n-Butyl acrylate. It has been found that styrene macroinitiator is highly efficient for the nitroxide mediated polymerization, even in very small concentration for the synthesis of poly n-butyl acrylate. High concentration of macroinitiator results in the formation of block copolymers of polystyrene and poly ( n-butyl acrylate) viz. polystyrene-block-poly-( n-butyl acrylate). The use of TEMPO toward controlled polymerization is of much importance, because it is the nitroxide commercially available at the lowest cost.

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