Gradient chitosan hydrogels modified with graphene derivatives and hydroxyapatite : physiochemical properties and initial cytocompatibility evaluation

In this study, we investigated preparation of gradient chitosan-matrix hydrogels through a novel freezing–gelling–thawing method. The influence of three types of graphene family materials (GFM), i.e., graphene oxide (GO), reduced graphene oxide (rGO), and poly(ethylene glycol) grafted graphene oxide (GO-PEG), as well as hydroxyapatite (HAp) on the physicochemical and biological properties of the composite hydrogels was examined in view of their potential applicability as tissue engineering scaffolds. The substrates and the hydrogel samples were thoroughly characterized by X-ray photoelectron spectroscopy, X-ray diffractometry, infrared spectroscopy, digital and scanning electron microscopy, rheological and mechanical analysis, in vitro chemical stability and bioactivity assays, as well as initial cytocompatibility evaluation with human umbilical cord Wharton’s jelly mesenchymal stem cells (hUC-MSCs). We followed the green-chemistry approach and avoided toxic cross-linking agents, using instead specific interactions of our polymer matrix with tannic acid, non-toxic physical cross-linker, and graphene derivatives. It was shown that the most promising are the gradient hydrogels modified with GO-PEG and HAp

Ash pollen in the air of selected Polish cities in 2010

W pracy przedstawiono analizę sezonu pylenia jesionu w wybranych punktach pomiarowych Polski w 2010 roku. Pomiary wykonano w Bydgoszczy, Krakowie, Lublinie, Olsztynie, Piotrkowie Trybunalskim, Sosnowcu, Szczecinie, Warszawie i Wrocławiu. Badania prowadzono metodą objętościową przy zastosowaniu aparatów typu Burkard i Lanzoni. Sezon pyłkowy jesionu rozpoczął się w pierwszej dekadzie kwietnia. Najwyższe wartości stężeń dobowych odnotowano w Lublinie, Warszawie, Bydgoszczy i Szczecinie (odpowiednio 311, 254, 231 i 226 ziaren/m3).This paper presents the course of ash pollination season in selected cites of Poland in 2010. The measurements were performed in Bydgoszcz, Kraków, Lublin, Olsztyn, Piotrków Trybunalski, Sosnowiec, Szczecin, Warszawa and Wrocław. The research was carried out by means of the volumetric method with the use of Burkard and Lanzoni devices. The ash pollen season started in the first decade of April. The highest concentration values were recorded in Lublin, Warszawa, Bydgoszcz and Szczecin (311, 254, 231 and 226 grains/m3)

The analysis of plantain pollen count in selected Polish cities in 2011

Praca przedstawia analizę sezonu pylenia babki w wybranych punktach pomiarowych w Polsce w 2011 roku. Badania wykonano metodą objętościową przy wykorzystaniu aparatów firmy Burkard i Lanzoni. Pierwsze ziarna pyłku babki pojawiły się w powietrzu atmosferycznym w pierwszej dekadzie maja. Najwyższe stężenie pyłku babki, wynoszące 28 z/m3, odnotowano w Krakowie w dniu 8 czerwca 2011 roku.This paper presents the course of plantain pollination season in selected cities of Poland in 2011. Volumetric method with the use of Volumetric Spore Trap (Burkard, Lanzoni) was implemented. The highest daily pollen count, that reached the level of 28 plantain pollen grains/m3, was recorded in Krakow in 08 June 2011

Very high grass pollen in the air of selected Polish cities in 2011 : prelimary report

Praca przedstawia wstępną analizę przebiegu sezonu pylenia traw w wybranych punktach pomiarowych w Polsce w 2011 roku. Badania prowadzono metodą objętościową przy wykorzystaniu aparatów firmy Burkard i Lanzoni. W 2011 roku zaobserwowano zwiększone nasilenie objawów chorobowych u osób z nadwrażliwością na alergeny pyłku traw. Sezon pylenia traw w 2011 roku charakteryzował się długimi ciągami dni z wysokim i bardzo wysokim stężeniem ich pyłku, co przełożyło się na większe nasilenie objawów chorobowych u osób uczulonych na alergeny pyłku traw.The paper presents preliminary analysis of grass pollen season of 2011 in selected measuring sites in Poland. The season was characterised by very intensive allergy symptoms in patients suffering from grass pollen allergens. Many days with high and very high pollen counts very noted

Biocomposites based on a balsa wood core containing intermediate layers made of coconut and sisal

Sandwich-type composite materials of various geometries were obtained, in which the inner layer was a laminate of glass fabric, and the core consisted of natural materials: balsa wood, coconut and sisal fibres. The materials were tested to determine the type of cracking process under static and dynamic stress conditions (impact strength). The best results were obtained for hybrid balsa/glass fabric composites with a spacer made of sisal mat. This type of system allows a controlled cracking process, which is a consequence of a different stress distribution. The research shows that the combination of different materials in a single composite, depending on their volume fraction, density and layering geometry, opens the way for use in technical constructions, especially where high specific strength is required. The work contains valuable results of research on sandwich materials, their behaviour under load, their modification, and their impact on the transfer of dynamic and static stresses. For the first time, a composition was tested containing a balsa tree core with transient elastic layers made of natural cellulose fibres