Environmental Degradability of Polyurethanes

The growing interest in environmental issues and increasing demands to develop materials that do not burden the natural environment significantly are currently observed. In this connection many studies on polymer degradation in different environments are carried out. It is important to consider the influence of synergistic action of various factors in order to understand the environmental degradation of synthetic polymers. This requires understanding of interactions between polymer and living organisms

Predicted Studies of Branched and Cross-Linked Polyurethanes Based on Polyhydroxybutyrate with Polycaprolactone Triol in Soft Segments

The number of cross-links in the non-linear polyurethane structure is the basic factor affecting its properties. Selected properties of aliphatic polyurethanes with soft segments made of different amounts of polycaprolactonetriol, polycaprolactonediol and synthetic, telechelic poly([R,S]-3-hydroxybutyrate) were determined. On the basis of changes in polyurethane properties, the correlation between these properties and the construction of soft segments was found. The structure of polyurethanes, their morphology, hydrophilicity, thermal and mechanical properties were examined. These properties were changed linearly up to 15% content of polycaprolactonetriol in soft segments. A further increase in the amount of triol causes that these properties are mainly determined by the high number of cross-links.This research was founded by the National Science Center Miniatura 2 project no. 2018/02/X/ST5/02005 and partially by the UMG research project no. WPiT/2020/PZ/01

Degradability of Polyurethanes and Their Blends with Polylactide, Chitosan and Starch

One of the methods of making traditional polymers more environmentally friendly is to modify them with natural materials or their biodegradable, synthetic equivalents. It was assumed that blends with polylactide (PLA), polysaccharides: chitosan (Ch) and starch (St) of branched polyurethane (PUR) based on synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) would degrade faster in the processes of hydrolysis and oxidation than pure PUR. For the sake of simplicity in the publication, all three modifiers: commercial PLA, Ch created by chemical modification of chitin and St are called bioadditives. The samples were incubated in a hydrolytic and oxidizing environment for 36 weeks and 11 weeks, respectively. The degradation process was assessed by observation of the chemical structure as well as the change in the mass of the samples, their molecular weight, surface morphology and thermal properties. It was found that the PUR samples with the highest amount of R,S-PHB and the lowest amount of polycaprolactone triol (PCLtriol) were degraded the most. Moreover, blending with St had the greatest impact on the susceptibility to degradation of PUR. However, the rate of weight loss of the samples was low, and after 36 weeks of incubation in the hydrolytic solution, it did not exceed 7% by weight. The weight loss of Ch and PLA blends was even smaller. However, a significant reduction in molecular weight, changes in morphology and changes in thermal properties indicated that the degradation of the samples should occur quickly after this time. Therefore, when using these polyurethanes and their blends, it should be taken into account that they should decompose slowly in their initial life. In summary, this process can be modified by changing the amount of R,S-PHB, the degree of cross-linking, and the type and amount of second blend component added (bioadditives).This research was founded by the National Science Center Poland Miniatura 2 project no. 2018/02/X/ST5/02005 and partially by the UMG research project no. WZNJ/2021/PZ/02

Degradability of cross-linked polyurethanes/chitosan composites

Polyurethanes with synthetic poly([R,S]-3-hydroxybutyrate) in the soft segment and with polycaprolactone triol as cross-linker were blended with chitosan and degraded in hydrolytic and oxidative solutions. Progress of the degradation of the samples was evaluated by changes in their weight, surface topography and thermal properties. Increasing the poly([R,S]-3-hydroxybutyrate) content in soft segment as well as blending with chitosan resulted in an increase in degradability of cross-linked polyurethanes in both solutions.Centre of Polymer and Carbon Materials, Polish Academy of Sciences, University of Wolverhampton, University of the Basque Country (UPV/EHU), Gdynia Maritime Universit

Branched polyurethanes based on synthetic polyhydroxybutyrate with tunable structure and properties

Branched, aliphatic polyurethanes (PURs) were synthesized and compared to linear analogues. The influence of polycaprolactonetriol and synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) in soft segments on structure, thermal and sorptive properties of PURs was determined. Using FTIR and Raman spectroscopies it was found that increasing the R,S-PHB amount in the structure of branched PURs reduced a tendency of urethane groups to hydrogen bonding. Melting enthalpies (on DSC thermograms) of both soft and hard segments of linear PURs were higher than branched PURs, suggesting that linear PURs were more crystalline. Oil sorption by samples of linear and branched PURs, containing only polycaprolactone chains in soft segments, was higher than in the case of samples with R,S-PHB in their structure. Branched PUR without R,S-PHB absorbed the highest amount of oil. Introducing R,S-PHB into the PUR structure increased water sorption. Thus, by operating the number of branching and the amount of poly([R,S]-3-hydroxybutyrate) in soft segments thermal and sorptive properties of aliphatic PURs could be controlled

Stanowisko Polskiego Towarzystwa Endokrynologicznego dotyczące związków endokrynnie czynnych (EDC)

With the reference to the position statements of the Endocrine Society, the Paediatric Endocrine Society, and the European Society of Paediatric Endocrinology, the Polish Society of Endocrinology points out the adverse health effects caused by endocrine disrupting chemicals (EDCs) commonly used in daily life as components of plastics, food containers, pharmaceuticals, and cosmetics. The statement is based on the alarming data about the increase of the prevalence of many endocrine disorders such as: cryptorchidism, precocious puberty in girls and boys, and hormone-dependent cancers (endometrium, breast, prostate). In our opinion, it is of human benefit to conduct epidemiological studies that will enable the estimation of the risk factors of exposure to EDCs and the probability of endocrine disorders. Increasing consumerism and the industrial boom has led to severe pollution of the environment with a corresponding negative impact on human health; thus, there is great necessity for the biomonitoring of EDCs in Poland. (Endokrynol Pol 2015; 66 (3): 276–285)    W nawiązaniu do opublikowanych ostatnio stanowisk Towarzystwa Endokrynologicznego (Endocrine Society), Towarzystwa Endokrynologii Pediatrycznej (Pediatric Endocrine Society) oraz Europejskiego Towarzystwa Endokrynologii Pediatrycznej (European Society of Pediatric Endocrinology), Polskie Towarzystwo Endokrynologiczne (PTE) zwraca uwagę na negatywne skutki zdrowotne spowodowane ekspozycją na związki endokrynnie czynne (EDC, endocrine disrupting chemicals) używane w przemyśle jako składowe plastików, opakowań żywności, leków oraz kosmetyków. Postępująca urbanizacja, industrializacja i konsumpcjonizm prowadzą do zwiększonego skażenia środowiska, które wpływa negatywnie na organizmy żywe, w tym również na ludzkie zdrowie. Obecnie znanych jest ponad 800 związków, które wykazują zdolność zaburzania czynności układu dokrewnego. Narastająca częstość występowania przypadków zaburzeń endokrynnych, zaburzeń rozwoju narządów płciowych, zaburzeń metabolicznych zwraca szczególną uwagę na potencjalną rolę czynników środowiskowych. Stanowisko PTE zostało sprowokowane alarmującymi danymi o wzroście częstości występowania: zaburzeń płodności, wnętrostwa, przedwczesnego dojrzewania płciowego dziewcząt i chłopców, nowotworów hormonozależnych, w tym raka endometrium, sutka, gruczołu krokowego, jajnika i jąder. W opinii autorów konieczne jest przeprowadzenie w Polsce reprezentatywnych, długoterminowych badań epidemiologicznych pozwalających na ocenę związku pomiędzy ekspozycją na EDC a występowaniem zaburzeń czynności gruczołów wydzielania wewnętrznego. Niezwykle ważne wydaje się stworzenie wielodyscyplinarnej grupy badawczej. Uzyskane wyniki po przedstawieniu przedstawicielom rządu, mogłyby umożliwić wprowadzenie stosownych rozporządzeń prawnych. (Endokrynol Pol 2015; 66 (3): 276–285)

Halogen Atoms in the Protein–Ligand System. Structural and Thermodynamic Studies of the Binding of Bromobenzotriazoles by the Catalytic Subunit of Human Protein Kinase CK2

Binding of a family of brominated benzotriazoles to the catalytic subunit of human protein kinase CK2 (hCK2α) was used as a model system to assess the contribution of halogen bonding to protein–ligand interaction. CK2 is a constitutively active pleiotropic serine/threonine protein kinase that belongs to the CMGC group of eukaryotic protein kinases (EPKs). Due to the addiction of some cancer cells, CK2 is an attractive and well-characterized drug target. Halogenated benzotriazoles act as ATP-competitive inhibitors with unexpectedly good selectivity for CK2 over other EPKs. We have characterized the interaction of bromobenzotriazoles with hCK2α by X-ray crystallography, low-volume differential scanning fluorimetry, and isothermal titration calorimetry. Properties of free ligands in solution were additionally characterized by volumetric and RT-HPLC measurements. Thermodynamic data indicate that the affinity increases with bromo substitution, with greater contributions from 5- and 6-substituents than 4- and 7-substituents. Except for 4,7-disubstituted compounds, the bromobenzotriazoles adopt a canonical pose with the triazole close to lysine 68, which precludes halogen bonding. More highly substituted benzotriazoles adopt many additional noncanonical poses, presumably driven by a large hydrophobic contribution to binding. Some noncanonical ligand orientations allow the formation of halogen bonds with the hinge region. Consistent with a predominantly hydrophobic interaction, the isobaric heat capacity decreases upon ligand binding, the more so the higher the substitution

The Role of School Social Support and School Social Climate in Dating Violence Victimization Prevention among Adolescents in Europe

The aim of the article is to show the role of school social support and school social climate in dating violence victimization prevention among adolescents in Europe. Study participants were students from secondary schools (age 13-16) in Spain, Italy, Romania, Portugal, Poland and UK. The analysis in this text concern student with dating experience (n=993) (57.2% of girls and 66.5% of boys). School social support was measured by School Social Climate, Factor 1 Scale (CECSCE) and by Student Social Support Scale (CASSS), subscales teachers and classmates. The association between school social support and different types of dating victimization (physical and/ or sexual dating violence, control dating violence and fear) was measured by calculating the prevalence ratios and their 95% confidence intervals, estimated by Poisson regression models with robust variance. All the models were adjusted by country and by sociodemographic variables. The results show that the average values of all types of social support are significantly lower in young people who have suffered any type of dating violence or were scared of their partner. The likelihood of suffering physical and/or sexual dating violence decreased when school social support increased [PR (CI95%): 0.96 (0.92; 0.99)]. In the same way, the likelihood of fear decreased when school social climate increased [PR (CI95%): 0.98 (0.96; 0.99)].There is an association between school social support and school social climate and experiences of being victim of dating violence among adolescents in Europe. Our results suggest that in the prevention of dating violence building a supportive climate at schools and building / using the support of peers and teachers is important

Current practice of care for adolescent and adult patients after Fontan surgery in Poland

Background: The growing number of adults patients after the Fontan operation requires regular surveillance tests in the specialized centers. Aims: Evaluation of current practice of care for Fontan patients in Poland based on a multicenter survey. Methods: Eight centers were included in the study-5 adult congenital heart disease (ACHD) and 3 pediatric centers for adolescents. To aim for a comparison between the centers and facilitate the interpretation of the results, the Fontan Surveillance Score (FSS) was developed. The higher score is consistent with better care, with a maximum of 19 points. Results: The number of 398 Fontan patients (243 adults and 155 adolescents [age 14-18 years]) was included in the study. The median FSS was 13 points with variability between the centers (interquartile range 7-14 points). Centers providing continuous care from the pediatric period until 18 years of age achieved a higher FSS compared to ACHD centers (median: 14 points vs 12 points, p< 0.001). Most of the patients, both in the ACHD (82.3%) and in pediatric centers (89%), were seen annually and had a physical examination, electrocardiogram, and echocardiogram performed at each visit. However, unsatisfactory utilization of tests identifying the early stages of Fontan circulation failure (cardiopulmonary exercise tests, cardiac magnetic resonance, liver biochemistry and imaging, detection of protein-losing enteropathy) was observed. Conclusions: The results of the study showed that there is no unified surveillance approach for Fontan patients in Poland. The practice of care for adults differs from that of adolescents