Poli(uretan-siloksani) na bazi hiperrazgranatog poliestra kao umreživača - sinteza i karakterizacija

A series of novel polyurethane crosslinked structures (PUs) was prepared from α,ω-dihydroxy-(ethylene oxide-poly(dimethylsiloxane)-ethylene oxide) (EO-PDMS-EO), 4,4'-methylenediphenyl diisocyanate and Boltorn ® hyperbranched polyester of the third pseudo generation. The hydroxyfunctional hyperbranched aliphatic polyester with 26 end groups was used as a crosslinking agent. In order to improve the compatibility of all the reactants during the synthesis, the PU samples were prepared by two-stage, step-growth polymerization in solution. The content of the soft EO-PDMS-EO segments was varied in the range from 15 to 40 wt. %. The influence of the EO-PDMS-EO content on the swelling behavior, crosslink density, hardness, and the thermal and surface properties of the synthesized PUs was investigated. The structure of the synthesized polyurethanes was confirmed by the presence of specific bands in the Fourier transform infrared spectra. Swelling studies were performed to determine the crosslink density and polyurethane networks with lower EO-PDMS-EO contents had higher crosslink densities. The glass transition temperature of the synthesized PUs, determined by differential scanning calorimetry, slightly increased from 50 to 58°C on decreasing the EO-PDMS-EO content because of the higher crosslink density of the samples. Increasing the EO-PDMS-EO content led to better thermal stability, as was evidenced by the onset temperature of weight loss. The surface of the polyurethane networks became more hydrophobic with increasing EO-PDMS-EO content. The surface morphology of synthesized polyurethanes was analyzed by scanning electron microscopy.U ovom radu prikazana je sinteza, struktura i neka svojstva novih umreženih poliuretana pripremljenih polazeći od α,ω-dihidroksi-(etilenoksid-poli(dimetilsiloksan)-etilenoksid) pretpolimera (EO-PDMS-EO), 4,4'-metilendifenildiizocijanata i Boltorn® hiperrazgranatog poliestra treće pseudo-generacije. Hiperrazgranati hidroksi funkcionalni alifatski poliestar sa 26 krajnjih grupa služio je kao umrežavajući agens pri sintezi poliuretana. U cilju poboljšanja kompatibilnosti reaktanata tokom sinteze, poliuretani su sintetisani dvostepenom polimerizacijom u rastvoru. Sadržaj mekog EO-PDMS-EO segmenta variran je u opsegu od 15 do 40 mas. %. Ispitan je uticaj EO-PDMS-EO sadržaja na ponašanje pri bubrenju, gustinu umrežavanja, tvrdoću, termička i površinska svojstva sintetisanih poliuretana. Struktura sintetisanih poliuretana potvrđena je FTIR spektroskopijom. Ponašanje pri bubrenju je ispitivano kako bi se odredila gustina umrežavanja i pokazano je da poliuretanske mreže sa nižim EO-PDMS-EO sadržajem imaju veću gustinu umrežavanja. Rezultati diferencijalne skenirajuće kalorimetrije pokazali su povećanje temperature ostakljivanja poliuretana od 50 do 58°C sa smanjenjem EO-PDMS-EO sadržaja kao posledicu veće gustine umreženosti uzoraka. Sintetisani poliuretani sa većim sadržajem EO-PDMS-EO segmenata pokazuju bolju termičku stabilnost, što je potvrđeno porastom početne temperature degradacije, određene TG analizom. Hidrofobnost površine poliuretana je rasla sa povećanjem sadržaja EO-PDMS-EO u odgovarajućem uzorku. Površinska morfologija sintetisanih poliuretana je analizirana skenirajućom elektronskom mikroskopijom

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Kinetics of aniline polymerization initiated with iron(III) chloride

The reaction kinetics of the chemical polymerization of aniline in aqueous acid solutions with FeCl3 as the oxidant (initiator) was investigated at 25 oC. The polymerization was performed in a special reactor which enabled the initial concentration of oxidant to be kept constant during the polymerization reaction. The order of the reaction of ANI polymerization with respect to FeCl3 was calculated as n = 0.18. The rate constant k of the polymerization reaction was found to be 9.1x10-5 (mol dm-3)-1,18 s-1. The theoretical yield of the reaction was calculated using the Faraday law and the experimentally determined quantity of electricity exchanged during the polymerization reaction. There was a discrepancy between the experimentally and theoretically determined yield, indicating that the oxidant was being consumed in some side reactions, which is an accordance with the fact that the order of the reaction of ANI polymerization with respect to FeCl3 is a non-integer number

The influence of some factors on the electrical conductivity and particle size of core/shell polystyrene/polyaniline composites

The electrically conductive, micron-sized, core/shell polystyrene (PS)/polyaniline (PANI) composite particles were synthesized by chemical oxidative polymerization of aniline in the presence of micron-sized PS particles in 1 M HCl. The conditions of the dispersion polymerization of styrene were optimized. The influence of the initiator type employed for the chemical oxidative polymerization of aniline and the aniline (ANI) concentration on the PS/PANI particle size and size distribution and their conductivity was investigated. The obtained results show that the conductivity of the samples increased with increasing ANI concentration. The conductivity of the PS/PANI composite particles obtained with the highest ANI concentration was of the same order of magnitude as that for PANI powder. The particle size did not depend on the concentration of ANI, while the particle size distribution was narrower at higher concentrations of ANI

Stabilization of a-glucosidase in organic solvents by immobilization on macroporous poly(GMA-co-EGDMA) with different surface characteristics

a-Glucosidase from baker’s yeast was immobilized on macroporous copolymers of ethylene glycol dimethacrylate and glycidyl methacrylate, poly(GMA-co-EGDMA), with various surface characteristics and pore sizes ranging from 44 nmto 270 nm. Immobilization was done by glutaraldehyde on the copolymer previously modified with 1,2-diaminoethane. The specific activity of the obtained immobilized enzyme varied from 27 to 81 U/g, depending on the employed copolymer. The half lives of the immobilized enzyme in cosolvents were influenced by the surface characteristics of the copolymer, ranging from 60 to 150 min in 35 % methanol and from 10 to 44 min in 45 % dimethyl sulphoxide (DMSO). The best stabilities were obtained when the enzyme was immobilized onto a copolymer having a pore size of 48 nm in methanol and 270 nm in DMSO

Composition and antifungal activity of the essential oil of Seseli annuum wild-growing in Serbia

The essential oil from the aerial parts of Seseli annuum, wild-growing in Serbia, was obtained by hydrodistillation and analyzed using GC and GC/MS. A total of 43 components were identified representing 96.5% of S. annuum oil. The most abundant compounds were germacrene D (29.8%), sabinene (10.3%), beta-ocimene Z (9.8%) and limonene (8.6%). The essential oil showed antifungal activity against fifteen fungi with MICs between 12.5 to 50 mu l/ml. (c) 2007 Elsevier B.V. All rights reserved