Estimation of the segmental interaction parameters of polymer blends based on styrene and 2,6-dimethyl-1,4-phenylene oxide derivatives

Using a mean-field model, the segmental interaction parameters of various polymer blends based on styrene and 2,6-dimethyl-phenylene oxide derivatives are revised using new experimental results and the \u27best fit values\u27 are established. The predictive qualities of the model are shown and suggestions about group-contribu­tion method are made, Calculations based on the revised segmental interaction parameters are in excellent agreement with the experimental data

Phase behaviour in blends of poly[styrene-co-ortho(para)-bromostyrene] and phenylsulfonated poly(2,6-dimethyl-1,4-phenylene oxide) copolymers

Random copolymers of styrene with ortho- or para-bromostyrene differ substantially in their blend behaviour with partly sulfonylated poly(2,6-dimethyl-l,4-phenylene oxide) (SPPO). Copolymers of styrene with ortho­bromostyrene exhibit a very narrow window of miscibility in comparison with styrene-para-bromostyrene copolymer blends with SPPOs. The experimental results can be accounted for on the basis of individual segmental interaction parameters by applying mean-field theory

Phase Behavior in Copolymer Blends of Poly(p-chlorostyrene-co-o-chlorostyrene) and Phenylsulfonylated Poly(2,6-dimethyl-1,4-phenylene oxide)

The miscibility of random copolymers of o-chlorostyrene and p -chlorostyrene [ P (oC1Stco-pC1St)] with partially phenylsulfonylated poly (2,6-dimethyl-1,4-phenylenoex ide)( SPPO) copolymers has been studied, using differential scanning calorimetry (DSC) toestablish Tg behavior. It already has been established that the isomeric effect of the chlorinesubstitution on miscibility is large. Thus the para-chloro-substituted styrenic homopolymeris miscible with all SPPOs containing more than - 5 mol % phenylsulfonylation, whereasthe ortho-chloro-substituted homopolymer is immiscible with the entire range of SPPOcopolymer compositions (and also with the respective homopolymers) . As a result of thisasymmetric behavior of the homopolymers, the width of the window of miscibility in blendsnow investigated containing copolymers with highpClSt content and SPPO is much greaterthan in the corresponding blends containing copolymers with large mole fraction of oC1St.These differences are reflected in the corresponding X parameters calculated from analysisof the data. It was also found that the miscibility is temperature dependent and that theregime in the copolymer-copolymer composition plane shrank as the equilibrium temperatureincreased, results indicative of LCST behavior

A novel Appendicitis TriMOdal prediction Score (ATMOS) for acute appendicitis in pregnancy: a retrospective observational study

Several scoring systems exist for the management of acute appendicitis (AA) during pregnancy. However, the systems are based on the nonpregnant adult population. The aim of this study was to create a highly accurate scoring system that can be applied to pregnant women and to compare it to the most commonly used scores in general population and pregnant women. The creation and subsequent implementation of a highly accurate score system could shorten the diagnostic period and minimize the use of (ionizing) diagnostic imaging allowing the selection of the best treatment approach in pregnant patients with acute appendicitis. A single-center, retrospective cohort observational study was conducted at the University Hospital Centre Zagreb, Zagreb, Croatia. Data were extracted from medical records of pregnant patients with suspected AA from January 2010 to December 2020. A total of 59 pregnant patients diagnosed with AA during pregnancy were identifed, 41 were treated surgically, and 18 had non-surgical management. The main objective of our study was the detection of predictive factors of AA during pregnancy. Anorexia, pain migration to the right lower quadrant, rebound pain, axillary temperature over 37.3 °C, CRP/platelet ratio>0.0422, neutrophil/lymphocyte ratio>7.182, and ultrasonic signs of AA were scored. Scoring in Appendicitis TriMOdal Score (ATMOS) consists of positive clinical parameter, each bringing 1 point and other parameters mentioned above that bring 2 points each. The score ranges from 0 to 10. Our model of ATMOS yields a high area under the receiver-operating characteristic curve of 0.963. The positive likelihood ratio is 9.97 (95% CI 2.64–38.00), and the negative likelihood ratio is 0.1 (95% CI 0.03–0.31), meaning that 94% of cases with ATMOS>4 have AA, while less than 13% with an ATMOS≤4 have the diagnosis of AA. The potential of ATMOS diferentiating AA during pregnancy was demonstrated. Future prospective, randomized trials are needed to evaluate its accuracy and whether it should be used instead of Alvarado or Tzanakis scores in clinical decision-makin