Polymer Knot in Solution near the θ Point

2020 ◽  
Vol 124 (13) ◽  
pp. 2723-2729 ◽  
Author(s):  
Xiaofei Xu ◽  
Xiangxiang Gao
Keyword(s):  
Θ Point

The Effect of Alternative Scoring Procedures on the Measurement Properties of a Self-Administered Depression Scale

2019 ◽  
Vol 35 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Noboru Iwata ◽  
Akizumi Tsutsumi ◽  
Takafumi Wakita ◽  
Ryuichi Kumagai ◽  
Hiroyuki Noguchi ◽  
...  
Keyword(s):  
Classical Test Theory ◽  
Depression Scale ◽  
Psychometric Testing ◽  
Epidemiologic Studies ◽  
Test Theory ◽  
Measurement Properties ◽  
Irt Model ◽  
Response Alternatives ◽  
Polytomous Item Response ◽  
Θ Point

Abstract. To investigate the effect of response alternatives/scoring procedures on the measurement properties of the Center for Epidemiologic Studies Depression Scale (CES-D) which has the four response alternatives, a polytomous item response theory (IRT) model was applied to the responses of 2,061 workers and university students (1,640 males, 421 females). Test information functions derived from the polytomous IRT analyses on the CES-D data with various scoring procedures indicated that: (1) the CES-D with its standard (0-1-2-3) scoring procedure should be useful for screening to detect subjects with “at high-risk” of depression if the θ point showing the highest information corresponds to the cut-off point, because of its extremely higher information; (2) the CES-D with the 0-1-1-2 scoring procedure could cover wider range of depressive severity, suggesting that this scoring procedure might be useful in cases where more exhaustive discrimination in symptomatology is of interest; and (3) the revised version of CES-D with replacing original positive items into negatively revised items outperformed the original version. These findings have never been demonstrated by the classical test theory analyses, and thus the utility of this kind of psychometric testing should be warranted to further investigation for the standard measures of psychological assessment.

Dynamics of lattice models of polymer chains near the Θ point

1990 ◽  
Vol 23 (11) ◽  
pp. 3013-3019 ◽  
Author(s):  
James Patton Downey ◽  
Jeffrey Kovac
Keyword(s):  
Lattice Models ◽  
Polymer Chains ◽  
Θ Point

scholarly journals Energy of the interacting self-avoiding walk at the θ point

2020 ◽  
Vol 102 (3) ◽  
Author(s):  
Simone Franchini ◽  
Riccardo Balzan
Keyword(s):  
Self Avoiding Walk ◽  
Θ Point

Thermodynamics of Non-Dilute Polymer Solutions

1967 ◽  
Vol 40 (1) ◽  
pp. 1-35 ◽  
Author(s):  
D. Patterson
Keyword(s):  
Polymer Solution ◽  
Polymer Solutions ◽  
Solution Thermodynamics ◽  
General Interest ◽  
Chain Molecules ◽  
Dilute Polymer Solutions ◽  
Mathematical Problems ◽  
The Subject ◽  
Further Development ◽  
Θ Point

Abstract An excellent new text, “Macromolecules in Solution,” by A. Morawetz emphasizes advances in polymer solution thermodynamics since publication of standard texts such as those of Tompa and Flory. Detailed development of the subject from 1950 may be followed in articles on polymers in Annual Reviews of Physical Chemistry, and particularly in the articles appearing every three years specially devoted to solution properties: Flory and Krigbaum (1951), Wall and Hiller (1954), Hermans (1957), Casassa (1960) and Hughes and von Frankenberg (1963). The articles on solutions of non-electrolytes are, of course, always of general interest and often deal directly with polymer solutions or mixtures of chain molecules. Because of this very satisfactory situation, the author has decided that the best thing is to review in more detail the single topic which is most interesting to him. This is the thermodynamics of non-dilute solutions where it is usually supposed that the quasi-lattice theories of the 40's are quite adequate at concentrations greater than about 10 per cent. For fifteen years or so, interest has centered on very dilute polymer solutions and the dimensions of isolated polymer molecules, particularly at temperatures near the θ point. Increasingly difficult mathematical problems have followed the McMillan-Mayer comparison of solutions and imperfect gases first applied to polymer solutions by Zimm and Stockmayer. Polymer solution thermodynamics seems to have moved far beyond the intuitive questions of Meyer as to why a polymer solution differs from an ideal solution or from a mixture of a monomeric solute and solvent. However, certain results, apparently not very widely known, make one feel that such qualitative questions are not out of date and that the thermodynamics of concentrated polymer solutions may be open to much further development.

THE SCANNING SIMULATION METHOD FOR MACROMOLECULES

1990 ◽  
Vol 01 (01) ◽  
pp. 119-145 ◽  
Author(s):  
HAGAI MEIROVITCH
Keyword(s):  
Critical Exponents ◽  
Simulation Method ◽  
Branched Polymers ◽  
Double Scanning ◽  
Scanning Method ◽  
Collapse Transition ◽  
Wide Range ◽  
The Stability ◽  
Future Work ◽  
Θ Point

We discuss the statistical properties of the scanning simulation method for macromolecules and its variant, the double scanning method. We summarize results (in particular critical exponents and transition temperatures) obtained for a wide range of models, branched polymers, polymers adsorbed on a surface and polymers at their collapse transition (the Flory θ-point). We describe application of the methods for studying the stability of polypeptides and discuss plans for future work.

Self-avoiding rings at the θ point

1990 ◽  
Vol 41 (6) ◽  
pp. 3074-3080 ◽  
Author(s):  
Dominique Maes ◽  
Carlo Vanderzande
Keyword(s):  
Θ Point

Osmotic pressure of semidilute polymer solution near the Θ point

1984 ◽  
Vol 81 (3) ◽  
pp. 1504-1506 ◽  
Author(s):  
Hiroyuki Ito ◽  
Osamu Koyama ◽  
Akio Chiba
Keyword(s):  
Polymer Solution ◽  
Osmotic Pressure ◽  
Semidilute Polymer Solution ◽  
Θ Point
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