Application of ICP-MS and various computational methods for drinking water quality assessment from the Silesian District (Southern Poland)

In this study, more than 200 samples of drinking water from taps in the Silesian District (southern Poland) were analyzed. Concentrations of As, Bi, Cd, Co, Cr, Mo, Ni, Pb, Rb, Sb, Se, Te, Tl and V were measured using inductively coupled plasma-mass spectrometry technique (ICP-MS). The levels of the tested elements generally met European Union regulations. All analytical results were processed using computational methods, including the Pearson and Gini coefficients with the Lorenz curves, one-way ANOVA, the Kruskal-Wallis one-way analysis of variance, the Mann-Whitney U test, the variance correlation test and the Spearman’s test. In addition, Principal Component Analysis (PCA) with Varimax and Cluster Analysis with Ward’s Method were applied. It was shown, that some parameters (e.g. hardness and alkalinity) were highly correlated. The score plot described the degree of mineralization of water samples, so the origin of water could be easily determined. In turn, based on the created dendrogram, the division of samples into several groups (with soft, medium and highly mineralized water) could be deduced.     

The ?NH?(C)?Br functionality of heteroaromatic compounds as a synthon for fused dihydrooxazoles

Fused dihydrooxazoles are produced by the reaction of 8‐bromoteophylline (1), 6‐bromo‐2‐pyridone (7), or 2‐bromobenzimidazole (11) with an N‐substituted N‐(2,3‐epoxypropyl)amine. The product derived from 1 undergoes rearrangement to a fused dihydrooxazine while the fused dihydrooxazoles derived from 7 and 11 are stable. J. Heterocyclic Chem., (2011).     

Synthesis,characterization and ethylene polymerization by metallasilsesquioxane

Soluble complexes of group (IV) metallocenes anchored on a substituted polyhedral oligomeric silsesquioxane trisilanol support were prepared and characterized. These catalyst precursors formulated as [M(O^O^O)X] are found to be active in polymerization of ethylene at high temperature in combination with ethylaluminum sesquichloride (Et₃Al₂Cl_3, EASC) as co‐catalyst. The polyethylene obtained by these catalysts is linear, crystalline and displays narrow dispersity. The unique low molecular weight PE formed in this reaction exhibits properties comparable to commercial micronized PE waxes that have potential industrial applications in surface coating and ink formulations. Copyright © 2013 John Wiley & Sons, Ltd.     

Synaptic plasticity modulates autonomous transitions between waking and sleep states: insights from a Morris-Lecar model

The transitions between waking and sleep states are characterized by considerable changes in neuronal firing. During waking, neurons fire tonically at irregular intervals and a desynchronized activity is observed at the electroencephalogram. This activity becomes synchronized with slow wave sleep onset when neurons start to oscillate between periods of firing (up-states) and periods of silence (down-states). Recently, it has been proposed that the connections between neurons undergo potentiation during waking, whereas they weaken during slow wave sleep. Here, we propose a dynamical model to describe basic features of the autonomous transitions between such states. We consider a network of coupled neurons in which the strength of the interactions is modulated by synaptic long term potentiation and depression, according to the spike time-dependent plasticity rule (STDP). The model shows that the enhancement of synaptic strength between neurons occurring in waking increases the propensity of the network to synchronize and, conversely, desynchronization appears when the strength of the connections become weaker. Both transitions appear spontaneously, but the transition from sleep to waking required a slight modification of the STDP rule with the introduction of a mechanism which becomes active during sleep and changes the proportion between potentiation and depression in accordance with biological data. At the neuron level, transitions from desynchronization to synchronization and vice versa can be described as a bifurcation between two different states, whose dynamical regime is modulated by synaptic strengths, thus suggesting that transition from a state to an another can be determined by quantitative differences between potentiation and depression.     

Suspension Fertilizers Based on Waste Phosphates from the Production of Polyols

Phosphorus raw materials are non-renewable, and their resources are shrinking faster and faster as a result of increased fertilizer production. This is due to the increasing population and the need to produce more food. Phosphorus, on the other hand, is one of the main nutrients of plants, without which it is impossible to conduct intensive agricultural production. There are no economically significant phosphate resources in Europe, so they must be imported. That is why it is so important to reduce losses and recover this element from waste streams, which was reflected in the new EU Regulation 2019/1009. A prospective option is to use waste phosphates from the production of polyether polyols. Previous studies show that they contain about 20% phosphorus. Due to their high water content, the most advantageous form of their application is the production of fertilizers in the form of a suspension. The aim of the study is to assess the possibility of using waste phosphates from the production of polyols as raw materials for the production of suspension fertilizers.     

Polytopes vibrations within Coxeter group symmetries

We are considering polytopes with exact reflection symmetry group G in the real 3-dimensional Euclidean spaceR³. By changingone simple element of the polytope (position of one vertex or length of an edge), one canretain the exact symmetry of the polytope by simultaneously changing other correspondingelements of the polytope. A simple method of using the symmetry of polytopes in order todetermine several resonant frequencies is presented. Knowledge of these frequencies, or atleast their ratios can be used for control of some principal changes of the polytopes.     

(Co)polymerization behavior of supported metallocene catalysts. I. Ligand and substituent effect

Ethylene polymerization and its copolymerization with 1‐hexene with a set of supported metallocene catalysts were studied. As a carrier, the complex of magnesium chloride with tetrahydrofuran, which was previously pretreated with a triisobutylaluminium (TIBA), was used. The investigated metallocene compound differs in the metal type (Zr or Ti), the nature of the alkyl substituent in the cyclopentadienyl ring, and the type of ligand (Cp or Ind). The effect of catalyst composition on the anchored metal content, catalyst activity, comonomer reactivity, and polymer properties was investigated. The results obtained with supported catalysts were compared with those obtained with their homogeneous counterparts under the same (co)polymerization conditions. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5562–5570, 2005     

Studies of structural composition distribution heterogeneity in ethylene/1-hexene copolymers using thermal fractionation technique (SSA): Effect of catalyst structure

Investigations into the compositional heterogeneity of ethylene/1-hexene copolymers obtained with various zirconocene/MAO catalysts, either homogeneous or supported on inorganic carriers such as a complex of magnesium chloride with tetrahydrofuran or methyl alcohol, were conducted. The dependence between metallocene structure, as well as catalyst immobilization, and the compositional heterogeneity of the related products was investigated. It was found that the heterogeneity of copolymers is determined by the metallocene catalyst structure. The amount of peaks on the DSC thermograms of copolymers and their division increase with the increase of bulkiness of the ligand in the catalytic system. The immobilization of the investigated catalysts on the magnesium carrier leads to an increase of the copolymer's compositional heterogeneity. However, the modification of the MgCl₂ carrier by tetrahydrofuran or methyl alcohol seems to not have any influence on the copolymers’ CCD.     

Antioxidant and Cytoprotective Properties of Plant Extract from Dry Flowers as Functional Dyes for Cosmetic Products

Nowadays, natural dyes are expected by the cosmetic and food industries. In contrast to synthetic dyes, colorants derived from natural sources are more environmentally friendly and safer for human health. In this work, plant extracts from Gomphrena globasa L., Clitoria ternatea L., Carthamus tinctorius L., Punica granatum L. and Papaver rhoeas L. as the natural and functional dyes for the cosmetics industry were assessed. Cytotoxicity on keratinocyte and fibroblast cell lines was determined as well as antioxidant and anti-aging properties by determining their ability to inhibit the activity of collagenase and elastase enzymes. In addition, the composition of the extracts was determined. The obtained extracts were also applied in face cream formulation and color analyses were performed. It has been shown that the obtained extracts were characterized by no cytotoxicity and a high antioxidant potential. The extracts also show strong ability to inhibit the activity of collagenase and moderate ability to inhibit elastase and provide effective and long-lasting hydration after their application on the skin. Application analyses showed that the extracts of P. rhoeas L., C. ternatea L. and C. tinctorius L. can be used as effective cosmetic dyes that allow for attainment of an intense and stable color during the storage of the product. The extracts of P. granatum L. and G. globasa L., despite their beneficial effects as active ingredients, did not work effectively as cosmetic dyes, because cosmetic emulsions with these extracts did not differ significantly in color from emulsions without the extract.     

pH‐Responsive Non‐Ionic Diblock Copolymers: Ionization of Carboxylic Acid End‐Groups Induces an Order–Order Morphological Transition

A carboxylic acid based reversible additionfragmentation transfer (RAFT) agent is used to prepare gels composed of worm‐like diblock copolymers using two non‐ionic monomers, glycerol monomethacrylate (GMA) and 2‐hydroxypropyl methacrylate (HPMA). Ionization of the carboxylic acid end‐group on the PGMA stabilizer block induces a worm‐to‐sphere transition, which in turn causes immediate degelation. This morphological transition is fully reversible as determined by TEM and rheology studies and occurs because of a subtle change in the packing parameter for the copolymer chains. A control experiment where the methyl ester derivative of the RAFT agent is used to prepare the same diblock copolymer confirms that no pH‐responsive behavior occurs in this case. This end‐group ionization approach is important for the design of new pH‐responsive copolymer nano‐objects as, unlike polyacids or polybases, only a minimal amount of added base (or acid) is required to drive the morphological transition.