Soil nutrient status and revegetation practices of downhill skiing areas in Finnish Lapland — a case study of Mt. Ylläs

Ski slope construction is one of the major anthropogenic factors responsible for ecosystem degradation in mountain areas in Finnish Lapland. Mt. Ylläs has been used as a downhill skiing slope for about 30 years. Until 1992, the ski slopes were kept in their natural condition: there was no removal of vegetation and soil above the tree line. After 1992, Mt. Ylläs went through an extensive construction, the ski slopes were machine-graded and machine-levelled, which caused damage to both vegetation and soil. The aim of the study presented here was to examine nutrient status of various soils on the machine-graded and machine-levelled ski slopes in relation to their potential use as a substrate for revegetation practices.Soil organic matter and nutrient status were analysed in three sites on the slopes of Mt. Ylläs in the tree line zone (transit zone between wooded vegetation and treeless alpine vegetation): (1) reference site on the undisturbed area between the ski-runs (Control); (2) disturbed site on the ski-run area (DSP — ‘DiSturbed Podzol’, DSL — ‘DiSturbed Leptosol’ and DSB — ‘DiSturbed Bare soil’); and (3) Revegetation study Plots established on the ski-runs (RP). The analysis of element concentrations and their relative proportions allow us to conclude that only DSP and DSL can be considered as potentially appropriate for unassisted ecosystem recovery on the ski-runs. Presence of native plant species on these patches supports our conclusion. As a recommendation for revegetation of ski-runs, we propose implementation of substrate composed of upper layer of initial soil. Such substrate can be collected during the construction work on ski slopes or on building sites in the area with similar soils. Uncomposted substrate or at least short period of composting is preferable.     

A Pilot Study of Changes in the Level of Catecholamines and the Activity of α-2-Macroglobulin in the Tear Fluid of Patients with Parkinson’s Disease and Parkinsonian Mice

Development of differential and early (preclinical) diagnostics of Parkinson’s disease (PD) is among the priorities in neuroscience. We searched for changes in the level of catecholamines and α-2-macroglobulin activity in the tear fluid (TF) in PD patients at an early clinical stage. It was shown that TF in patients is characterized by an increased level of noradrenaline mainly on the ipsilateral side of pronounced motor symptoms (72%, p = 0.049), a decreased level of adrenaline on both sides (ipsilateral—53%, p = 0.004; contralateral—42%, p = 0.02), and an increased α-2-macroglobulin activity on both sides (ipsilateral—53%, p = 0.03; contralateral—56%, p = 0.037) compared to controls. These changes are considered as potential biomarkers for differential diagnosis. Similar changes in the TF were found in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice when modeling clinical and preclinical stages of PD. These data show the adequacy of models to the pathogenesis of PD along the selected metabolic pathways, and also suggest that the found TF changes can be considered as potential biomarkers for preclinical diagnosis of PD. In Parkinsonian mice, the level of catecholamines also changes in the lacrimal glands, which makes it possible to consider them as one of the sources of catecholamines in the TF.     

Switching Ion Binding Selectivity of Thiacalix[4]arene Monocrowns at Liquid–Liquid and 2D-Confined Interfaces

Understanding the interaction of ions with organic receptors in confined space is of fundamental importance and could advance nanoelectronics and sensor design. In this work, metal ion complexation of conformationally varied thiacalix[4]monocrowns bearing lower-rim hydroxy (type I), dodecyloxy (type II), or methoxy (type III) fragments was evaluated. At the liquid–liquid interface, alkylated thiacalixcrowns-5(6) selectively extract alkali metal ions according to the induced-fit concept, whereas crown-4 receptors were ineffective due to distortion of the crown-ether cavity, as predicted by quantum-chemical calculations. In type-I ligands, alkali-metal ion extraction by the solvent-accessible crown-ether cavity was prevented, which resulted in competitive Ag⁺ extraction by sulfide bridges. Surprisingly, amphiphilic type-I/II conjugates moderately extracted other metal ions, which was attributed to calixarene aggregation in salt aqueous phase and supported by dynamic light scattering measurements. Cation–monolayer interactions at the air–water interface were monitored by surface pressure/potential measurements and UV/visible reflection–absorption spectroscopy. Topology-varied selectivity was evidenced, towards Sr²⁺ (crown-4), K⁺ (crown-5), and Ag⁺ (crown-6) in type-I receptors and Na⁺ (crown-4), Ca²⁺ (crown-5), and Cs⁺ (crown-6) in type-II receptors. Nuclear magnetic resonance and electronic absorption spectroscopy revealed exocyclic coordination in type-I ligands and cation–π interactions in type-II ligands.     

Involutive Divisions. Graphs

A new approach to the theory of involutive divisions is suggested. The application of this approach simplifies the formulation of definitions and properties and makes it possible to obtain new involutive divisions. The latter feature is important in light of the results discussed in [1]. An involutive division graph is defined, and the notions of its completeness and projection are introduced. Criteria for being global and Noetherian and a sufficient condition for the completeness are obtained.     

Effects of Oleic Acid and Phospholipids on the Formation of Lecithin Organogel and Microemulsion

The formation of organogels and microemulsions of lecithin in the presence of a biocompatible cosurfactant, oleic acid, was studied. Low content of oleic acid ([oleic acid]/[lecithin] < 0.1) in the lecithin–oleic acid–dodecane–water system leads to an expansion of the region of existence and to a decrease in the viscosity of lecithin organogels. At high contents of oleic acid ([oleic acid]/[lecithin] > 0.6), low‐viscosity microemulsion exists in the system. Phosphatidylethanolamine, lysophosphatidylcholine, and other phospholipids that are present as impurities in the commercial samples of soybean lecithin can act as cosurfactants. For the first time, the formation of lecithin organogels in the systems containing commercial samples of soybean lecithin with phosphatidylcholine concentrations of 69.3 wt% (Lipoid S75) and 52.9 wt% (Lipoid S45) and saturated aliphatic hydrocarbons is demonstrated. The gelation is observed at T =25 °C in octane, decane, dodecane, and hexadecane for Lipoid S75 and in dodecane and hexadecane for Lipoid S45. A decrease in the degree of purification of lecithin leads to an expansion of the regions of existence of the organogels and to a reduction of their viscosity.     

Novel spray-dried PHA microparticles for antitumor drug release

The production of poly-3-hydroxybutyrate (P3HB) and poly-3-hydroxybutyrate/polyethylene glycol (PEG)-based microparticles, loaded with antitumor drugs paclitaxel (PTX) and 5-Fluorouracil (5-FU) by spray-drying technique, was investigated. The average diameter of microparticles was found to be 3.4?±?0.5?µm and zeta potential was about ?44?mV. The addition of surfactant PEG did not show any effect on the morphological characteristics of the particles. But the chemical structure of drug influenced on the properties. Microparticles had heterogeneous pores on the surface when the hydrophobic PTX was encapsulated. It was established that the addition of surfactant positively influenced on the properties of particles and led to the loading of 5-FU directly into the matrix. This is confirmed by the results of electron microscopy and dynamics of drug release in vitro. As a whole, the release profiles of PTX and 5-FU from composite P3HB/PEG microparticles were less than from P3HB microparticles. The results of the morphological evaluation of Hela cells demonstrated that the use of cytostatic drugs loaded in P3HB microparticles induces morphological changes associated with apoptosis (chromatin condensation, core fragmentation, margination of nucleus). Thus, the obtained results can serve as the basis for the development of new antitumor drugs of prolonged action, intended for various modes of administration.     

A matheuristic for the discrete bilevel problem with multiple objectives at the lower level

In this paper, we solve a discrete bilevel problem with multiple objectives at the lower level and constraints at the upper level coupling variables of both levels. In the case of a multiobjective lower level, we deal with a set of Pareto‐efficient solutions rather than a single optimal lower level solution. To calculate the upper level objective function value, we need to select one solution out of a potentially large set of efficient lower level solutions. To avoid the enumeration of the whole set of Pareto solutions, we formulate an auxiliary mixed integer linear programming problem with a large number of constraints. We propose an iterative exact method to solve it. To find a near‐optimal upper level solution, we apply a metaheuristic. The method is tested on the discrete ()‐centroid problem with multiple objectives at the lower level.     

Boundary objects in collaborative work and learning

Boundary objects are artifacts, processes, concepts and other entities that provide bridges across boundaries and act as shared references that are meaningful for learners and collaborators with different backgrounds. In this paper, we explore cooperation in a cross-disciplinary and cross-cultural context, focusing on the opportunities for learning that arise at different boundaries and on corresponding boundary objects to facilitate both collaboration and learning. We present and discuss a study we conducted within a Cooperation Technology course. The discussion provides implications for collaboration support across boundaries, including insights on why they are important, how to facilitate their creation, and how to use technologies for that. The implications are formulated as instruction for designing university courses, but can be used in a wider context.     

Micelles of polyisobutylene-block-poly(methacrylic acid) diblock copolymers and their water-soluble interpolyelectrolyte complexes formed with quaternized poly(4-vinylpyridine)

The micellization of ionic amphiphilic diblock copolymers, polyisobutylene-block-poly(methacrylic acid) (PIB-b-PMAA), with a constant degree of polymerization of the non-ionic block and various degrees of polymerization of the polyelectrolyte block was examined in aqueous media by means of fluorescence spectroscopy using pyrene as a polarity probe. The molar values of the critical micellization concentration (cmc) were found to be around 2×10⁻⁶ mol/l, being nearly independent of the length of the polyelectrolyte block as well as pH (in the range 6-9) and ionic strength (≤0.5 M NaCl) while the specific cmc values varied from 20 to 100 mg/l. Small-angle neutron scattering (SANS) and dynamic light scattering (DLS) experiments provided evidence that aggregation numbers and hydrodynamic radii of the formed copolymer micelles are sensitive to variations of pH and ionic strength, indicating that these micelles might be ‘dynamic’ rather than ‘frozen’ ones. It was also shown by means of a combination of turbidimetry, analytical ultracentrifugation, fluorescence spectroscopy, SANS, and DLS that the formed copolymer micelles mixed with a strong cationic polyelectrolyte, poly(N-ethyl-4-vinylpyridinium bromide) at charge ratio Z=[+]/[−] not exceeding a certain critical value Z_M<1, generate peculiar water-soluble micellar complex onion-like species, each containing a two-phase hydrophobic nucleus and a hydrophilic corona. The nucleus consists of a PIB core and a shell assembled from the fragments of water-insoluble interpolyelectrolyte complex. The corona is formed by the excess fragments of poly(sodium methacrylate) blocks not involved in complexation with poly(N-ethyl-4-vinylpyridinium bromide).