scholarly journals High-Performance UV-Vis Light Induces Radical Photopolymerization Using Novel 2-Aminobenzothiazole-Based Photosensitizers

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7814
Author(s):  
Alicja Balcerak ◽  
Janina Kabatc ◽  
Zbigniew Czech ◽  
Małgorzata Nowak ◽  
Karolina Mozelewska
Keyword(s):  
Radical Polymerization ◽  
High Performance ◽  
Polymeric Materials ◽  
Polymerization Reaction ◽  
Medical Sector ◽  
Light Absorber ◽  
Trimethylolpropane Triacrylate ◽  
The Subject ◽  
Radical Initiators

The popularity of using the photopolymerization reactions in various areas of science and technique is constantly gaining importance. Light-induced photopolymerization is the basic process for the production of various polymeric materials. The key role in the polymerization reaction is the photoinitiator. The huge demand for radical and cationic initiators results from the dynamic development of the medical sector, and the optoelectronic, paints, coatings, varnishes and adhesives industries. For this reason, we dealt with the subject of designing new, highly-efficient radical photoinitiators. This paper describes novel photoinitiating systems operating in UV-Vis light for radical polymerization of acrylates. The proposed photoinitiators are composed of squaraine (SQ) as a light absorber and various diphenyliodonium (Iod) salts as co-initiators. The kinetic parameters of radical polymerization of trimethylolpropane triacrylate (TMPTA), such as the degree of double bonds conversion (C%), the rate of photopolymerization (Rp), as well as the photoinitiation index (Ip) were calculated. It was found that 2-aminobenzothiazole derivatives in the presence of iodonium salts effectively initiated the polymerization of TMPTA. The rates of polymerization were at about 2 × 10−2 s−1 and the degree of conversion of acrylate groups from 10% to 36% were observed. The values of the photoinitiating indexes for the most optimal initiator concentration, i.e., 5 × 10−3 M were in the range from 1 × 10−3 s−2 even to above 9 × 10−3 s−2. The photoinitiating efficiency of new radical initiators depends on the concentration and chemical structure of used photoinitiator. The role of squaraine-based photoinitiating systems as effective dyeing photoinitiators for radical polymerization is highlighted in this article.

Effect of polyarylene ether nitrile on the curing behaviors and properties of bisphthalonitrile

2016 ◽  
Vol 23 (6) ◽  
pp. 579-588
Author(s):  
Zhiran Chen ◽  
Yajie Lei ◽  
Hailong Tang ◽  
Xiaobo Liu
Keyword(s):  
High Performance ◽  
Polymer Networks ◽  
Polymeric Materials ◽  
Interpenetrating Polymer Networks ◽  
Polymerization Reaction ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Polyarylene Ether Nitrile ◽  
Heat Polymerization

AbstractThe 2,2-bis[4-(3,4)-dicyanophenoxy phenyl]propane (BAPh)/polyarylene ether nitrile (PEN-OH) prepolymers and polymers were prepared by heat polymerization. Firstly, BAPh/PEN-OH systems were characterized using differential scanning calorimetry, dynamic rheological analysis, and thermal gravimetric analysis. The results revealed that the polymerization reaction can be controlled by various concentrations of PEN-OH and postcuring temperatures, and BAPh/PEN-OH prepolymers had low curing temperatures (229.3–300.4°C), large processing windows (∼106.5°C) with low melt viscosities, and excellent thermal stabilities. Then, the polymerization reaction and surface structures of BAPh/PEN-OH systems were investigated using Fourier transform infrared and scanning electron microscopy, respectively. The interpenetrating polymer networks were found in BAPh/PEN-OH polymers, suggesting that the addition of PEN-OH can not only promote the curing behaviors of BAPh but also increase the toughness of the polymers. The flexure strength and modulus of BAPh/PEN-OH polymers increased with the introduction of PEN-OH. The dielectric properties of BAPh/PEN-OH polymers were investigated, which had little dependence on the frequency. BAPh/PEN-OH systems can be used as a good candidate for high-performance polymeric materials.

Trace nanoanalysis

1994 ◽  
Vol 52 ◽  
pp. 940-941
Author(s):  
D. E. Newbury ◽  
R. D. Leapman
Keyword(s):  
High Performance ◽  
Secondary Ion Mass Spectrometry ◽  
Detection Efficiency ◽  
Volume Element ◽  
And Performance ◽  
Trace Constituents ◽  
Secondary Ion ◽  
Concentration Levels ◽  
Structure Properties

Trace constituents, which can be very loosely defined as those present at concentration levels below 1 percent, often exert influence on structure, properties, and performance far greater than what might be estimated from their proportion alone. Defining the role of trace constituents in the microstructure, or indeed even determining their location, makes great demands on the available array of microanalytical tools. These demands become increasingly more challenging as the dimensions of the volume element to be probed become smaller. For example, a cubic volume element of silicon with an edge dimension of 1 micrometer contains approximately 5×1010 atoms. High performance secondary ion mass spectrometry (SIMS) can be used to measure trace constituents to levels of hundreds of parts per billion from such a volume element (e. g., detection of at least 100 atoms to give 10% reproducibility with an overall detection efficiency of 1%, considering ionization, transmission, and counting).

Top-Down Processing and Visual Reorientation Illusions in a Virtual Reality Environment

2004 ◽  
Vol 63 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Fred W. Mast ◽  
Charles M. Oman
Keyword(s):  
Virtual Reality ◽  
Visual Processing ◽  
Line Length ◽  
Perceptual Cues ◽  
Virtual Reality Environment ◽  
Top Down ◽  
Test Conditions ◽  
The Subject ◽  
Processing Mechanisms

The role of top-down processing on the horizontal-vertical line length illusion was examined by means of an ambiguous room with dual visual verticals. In one of the test conditions, the subjects were cued to one of the two verticals and were instructed to cognitively reassign the apparent vertical to the cued orientation. When they have mentally adjusted their perception, two lines in a plus sign configuration appeared and the subjects had to evaluate which line was longer. The results showed that the line length appeared longer when it was aligned with the direction of the vertical currently perceived by the subject. This study provides a demonstration that top-down processing influences lower level visual processing mechanisms. In another test condition, the subjects had all perceptual cues available and the influence was even stronger.

Two Short Tests Fail to Detect Vigilance Decrements

2001 ◽  
Vol 17 (1) ◽  
pp. 48-55 ◽  
Author(s):  
Juan Botella ◽  
María José Contreras ◽  
Pei-Chun Shih ◽  
Víctor Rubio
Keyword(s):  
Individual Differences ◽  
High Performance ◽  
Selection Process ◽  
Vigilance Task ◽  
Air Traffic Controllers ◽  
Job Selection ◽  
Performance Deterioration ◽  
Short Test ◽  
Psychological Dimensions

Summary: Deterioration in performance associated with decreased ability to sustain attention may be found in long and tedious task sessions. The necessity for assessing a number of psychological dimensions in a single session often demands “short” tests capable of assessing individual differences in abilities such as vigilance and maintenance of high performance levels. In the present paper two tasks were selected as candidates for playing this role, the Abbreviated Vigilance Task (AVT) by Temple, Warm, Dember, LaGrange and Matthews (1996) and the Continuous Attention Test (CAT) by Tiplady (1992) . However, when applied to a sample of 829 candidates in a job-selection process for air-traffic controllers, neither of them showed discriminative capacity. In a second study, an extended version of the CAT was applied to a similar sample of 667 subjects, but also proved incapable of properly detecting individual differences. In short, at least in a selection context such as that studied here, neither of the tasks appeared appropriate for playing the role of a “short” test for discriminating individual differences in performance deterioration in sustained attention.

Baboon Fibrinogen Adsorption and Platelet Adhesion to Polymeric Materials

1991 ◽  
Vol 65 (05) ◽  
pp. 608-617 ◽  
Author(s):  
Joseph A Chinn ◽  
Thomas A Horbett ◽  
Buddy D Ratner
Keyword(s):  
Platelet Adhesion ◽  
Coagulation Factor ◽  
Polymeric Materials ◽  
Platelet Suspension ◽  
Perfusion Chamber ◽  
Static Conditions ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Fibrinogen Adsorption

SummaryThe role of fibrinogen in mediating platelet adhesion to polymers exposed to blood plasma was studied by comparison of the effect of plasma dilution on fibrinogen adsorption and platelet adhesion, and by the use of coagulation factor deficient plasmas. Polyetherurethane substrates were first preadsorbed with dilute plasma, then contacted with washed platelets suspended in a modified, apyrase containing Tyrode’s buffer. Platelet adhesion was studied under static conditions in Multiwell dishes, and also under shearing conditions using a parallel plate perfusion chamber. Fibrinogen adsorption and platelet adhesion were measured using 125I radiolabeled baboon fibrinogen and min radiolabeled baboon platelets, respectively. Surfaces were characterized by electron spectroscopy for chemical analysis (ESCA).When fibrinogen adsorption to Biomer was measured after 2 h contact with a series of dilute plasma solutions under static conditions, a peak in adsorption was observed from 0.26% plasma, i.e., adsorption was greater from 0.26% plasma than from either more or less dilute plasma. A peak in subsequent platelet adhesion to the plasma preadsorbed surfaces, measured after 2 h static incubation with washed platelets, was also observed but occurred on Biomer preadsorbed with 1.0% plasma.When fibrinogen adsorption was measured after 5 min contact under shearing conditions, the fibrinogen adsorption peak occurred on surfaces that had been exposed to 1.0% plasma. A peak in platelet adhesion to these preadsorbed surfaces, measured after 5 min contact with the platelet suspensions under shearing conditions, was observed on Biomer preadsorbed with 0.1% plasma. Shifts between the positions of the peaks in protein adsorption and platelet adhesion occurred on other polymers tested as well.Platelet adhesion was almost completely inhibited when baboon and human plasmas lacking fibrinogen (i. e., serum, heat defibrinogenated plasma, and congenitally afibrinogénémie plasma) were used. Platelet adhesion was restored to near normal when exogenous fibrinogen was added to fibrinogen deficient plasmas. Adhesion was also inhibited completely when a monoclonal antibody directed against the glycoprotein IIb/IIIa complex was added to the platelet suspension. Platelet adhesion to surfaces preadsorbed to von Willebrand factor deficient plasma was the same as to surfaces preadsorbed with normal plasma.While it appears that surface bound fibrinogen does mediate the initial attachment of platelets to Biomer, the observation that the fibrinogen adsorption and platelet adhesion maxima do not coincide exactly also suggests that the degree of subsequent platelet adhesion is dictated not only by the amount of surface bound fibrinogen but also by its conformation.

The future role of the psychiatrist in Europe – a UEMS perspective

2014 ◽  
Vol 11 (01) ◽  
pp. 35-42
Author(s):  
M. Hermans
Keyword(s):  
Mental Health ◽  
Mental Health Professionals ◽  
Health Professionals ◽  
General Interest ◽  
Future Role ◽  
Personal Opinion ◽  
The Future ◽  
The Subject ◽  
The Many

SummaryThe author presents his personal opinion inviting to discussion on the possible future role of psychiatrists. His view is based upon the many contacts with psychiatrists all over Europe, academicians and everyday professionals, as well as the familiarity with the literature. The list of papers referred to is based upon (1) the general interest concerning the subject when representing ideas also worded elsewhere, (2) the accessibility to psychiatrists and mental health professionals in Germany, (3) being costless downloadable for non-subscribers and (4) for some geographic aspects (e.g. Belgium, Spain, Sweden) and the latest scientific issues, addressing some authors directly.

Alignment

2016 ◽  
pp. 33-50
Author(s):  
Pier Giuseppe Rossi
Keyword(s):  
Teaching And Learning ◽  
Enactive Approach ◽  
The World ◽  
Strategic Role ◽  
Education Today ◽  
Current Context ◽  
The Subject

The subject of alignment is not new to the world of education. Today however, it has come to mean different things and to have a heuristic value in education according to research in different areas, not least for neuroscience, and to attention to skills and to the alternation framework.This paper, after looking at the classic references that already attributed an important role to alignment in education processes, looks at the strategic role of alignment in the current context, outlining the shared construction processes and focusing on some of the ways in which this is put into effect.Alignment is part of a participatory, enactive approach that gives a central role to the interaction between teaching and learning, avoiding the limits of behaviourism, which has a greater bias towards teaching, and cognitivism/constructivism, which focus their attention on learning and in any case, on that which separates a teacher preparing the environment and a student working in it.

TheOrvosi Hetilap (Hungarian Medical Journal)in the network of medical journals

2014 ◽  
Vol 155 (22) ◽  
pp. 876-879
Author(s):  
András Schubert
Keyword(s):  
Medical Journal ◽  
Scientific Knowledge ◽  
Knowledge Network ◽  
Scientific Journals ◽  
Scientific Enterprise ◽  
Medical Journals ◽  
The Subject

The role of networks is swiftly increasing in the production and communication of scientific knowledge. Network aspects have, therefore, an ever growing importance in the analysis of the scientific enterprise, as well. The present paper demonstrates some techniques of studying the network of scientific journals on the subject of seeking the position of Orvosi Hetilap (Hungarian Medical Journal) in the international journal network. Orv. Hetil., 2014, 155(22), 876–879.

The Impact of Quantitative Easing on Emerging Markets – Literature Review

e-Finanse ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 67-76
Author(s):  
Piotr Bartkiewicz
Keyword(s):  
Emerging Markets ◽  
Large Scale ◽  
Empirical Literature ◽  
Quantitative Easing ◽  
Methodological Choices ◽  
The Subject ◽  
Methodological Approaches ◽  
The Impact ◽  
Sufficient Precision

AbstractThe article presents the results of the review of the empirical literature regarding the impact of quantitative easing (QE) on emerging markets (EMs). The subject is of interest to policymakers and researchers due to the increasingly larger role of EMs in the world economy and the large-scale capital flows occurring after 2009. The review is conducted in a systematic manner and takes into consideration different methodological choices, samples and measurement issues. The paper puts the summarized results in the context of transmission channels identified in the literature. There are few distinct methodological approaches present in the literature. While there is a consensus regarding the direction of the impact of QE on EMs, its size and durability have not yet been assessed with sufficient precision. In addition, there are clear gaps in the empirical findings, not least related to relative underrepresentation of the CEE region (in particular, Poland).

Contemporary Machiavellian theses "The strategy of the role of the absurd state as a model"

2020 ◽  
pp. 3
Author(s):  
Ali Hussein Hameed ◽  
Saif Hayder AL.Husainy
Keyword(s):  
International Relations ◽  
Decision Maker ◽  
Turning Point ◽  
Information Revolution ◽  
Main Hypothesis ◽  
The Subject ◽  
Area Of Influence ◽  
The Right ◽  
Modern Technologies

In the anarchism that governs the nature and patterns of international relations characterized by instability and uncertainty in light of several changes, as well as the information revolution and the resulting developments and qualitative breakthroughs in the field of scientific and advanced technological knowledge and modern technologies.  All of these variables pushed toward the information flow and flow tremendously, so rationality became an indispensable matter for the decision maker as he faces these developments and changes. There must be awareness and rationality in any activity or behavior because it includes choosing the best alternative and making the right decision and selecting the information accurately and mental processing Through a mental system based on objectivity, methodology, and accumulated experience away from idealism and imagination, where irrationality and anarchy are a reflection of the fragility of the decision-maker, his lack of awareness of the subject matter, his irresponsibility, and recklessness that inevitably leads to failure by wasting time and Effort and potential. The topic acquires its importance from a search in the strategies of the frivolous state and its characteristics with the ability to influence the regional, and what it revealed is a turning point in how to adapt from the variables and employ them to their advantage and try to prove their existence. Thus, the problem comes in the form of a question about the possibility of the frivolous state in light of the context of various regional and international events and trends. The answer to this question stems from the main hypothesis that (the aim which the frustrating state seeks to prove is that it finds itself compelled to choose several strategies that start from the nature of its characteristics and the goals that aim at it, which are centered in the circle of its interests in the field of its struggle for the sake of its survival and area of influence).

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