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The problem of consolidation of soil has been widely investigated. The basic approach was given by Terzaghi who assumed soil of constant physical and mechanical parameters. In the case of peat consolidation, the permeability coefficient of soil and the elasticity modulus are functions of the settlement which is an important additional factor. The model proposed here assumes varying the elasticity and permeability coefficients. Moreover, the settlement is described by the so-called elementary curve which was approximated empirically based upon laboratory tests. The model allows to consider the case when the filtration in the peat body goes in horizontal direction. It happens so when the charging layer does not receive outgoing water from the pores. The model includes also the case when the load involving consolidation varies in time i.e. the charging layer grows up gradually. The model has been applied practically in several cases and it comes that there is a good agreement between calculated and measured settlement of the consolidated peat layer.

Metastrongyloid nematodes typically reside as adults in the cardiopulmonary systems of their mammalian definitive hosts, potentially causing severe diseases. Of particular concern are Angiostrongylus cantonensis and A. costaricensis, which can cause eosinophilic meningitis and abdominal angiostrongyliasis, respectively, in their accidental human hosts. Several metastrongyloid species of medical and veterinary importance have been documented in the Canary Islands. However, the gastropod species acting as intermediate hosts for some of these nematodes in the archipelago remained unknown. This study aimed to investigate the occurrence of metastrongyloid nematodes in terrestrial and aquatic gastropods, including both endemic and non-native species, on Tenerife. Foot samples from terrestrial and aquatic gastropods were analyzed using a multiplex PCR targeting the Internal Transcribed Spacer 1 (ITS1), allowing the specific detection of A. cantonensis, A. vasorum, Aelurostrongylus abstrusus, Crenosoma striatum, Troglostrongylus brevior, and Crenosoma vulpis. Five metastrongyloid species, namely C. striatum, A. cantonensis, Ae. abstrusus, A. vasorum, and an unidentified metastrongyloid, were identified within both non-native and endemic terrestrial gastropods. In the aquatic snail Physella acuta, only A. cantonensis and C. striatum were detected. This study confirms the introduction of various metastrongyloids associated with non-native mammalian fauna and provides new data on the occurrence of these nematodes in non-native and endemic gastropod species, including their presence in aquatic environments on the Canary Islands., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Polypropylene-based aerogels with high surface area have been developed for the first time. By chemical crosslinking of polypropylene with oligomeric capped-end amino compounds, followed by dissolution, thermally induced phase separation, and the supercritical CO 2 drying process or freeze-drying method, the aerogels exhibit high specific surface areas up to 200 m 2 /g. Moreover, the silica-cage multi-amino compound was utilized in a similar vein for forming hybrid polypropylene aerogels. According to the SEM, the developed polypropylene-based aerogels exhibit highly porous morphology with micro-nanoscale structural features that can be controlled by processing conditions. Our simple and inexpensive synthetic strategy results in a low-cost, chemically resistant, and highly porous material that can be tailored according to end-use applications.

The inherent disadvantages of traditional non-flexible aerogels, such as high fragility and moisture sensitivity, severely restrict their applications. To address these issues and make the aerogels efficient, especially for advanced medical applications, different techniques have been used to incorporate flexibility in aerogel materials. In recent years, a great boom in flexible aerogels has been observed, which has enabled them to be used in high-tech biomedical applications. The current study comprises a comprehensive review of the preparation techniques of pure polymeric-based hybrid and single-component aerogels and their use in biomedical applications. The biomedical applications of these hybrid aerogels will also be reviewed and discussed, where the flexible polymeric components in the aerogels provide the main contribution. The combination of highly controlled porosity, large internal surfaces, flexibility, and the ability to conform into 3D interconnected structures support versatile properties, which are required for numerous potential medical applications such as tissue engineering; drug delivery reservoir systems; biomedical implants like heart stents, pacemakers, and artificial heart valves; disease diagnosis; and the development of antibacterial materials. The present review also explores the different mechanical, chemical, and physical properties in numerical values, which are most wanted for the fabrication of different materials used in the biomedical fields.

The inherent disadvantages of traditional nonflexible aerogels, such as high fragility and moisture sensitivity, severely restrict their applications. To address these issues, different techniques have been used to incorporate the flexibility in aerogel materials; hence, the term "flexible aerogels" was introduced. In the case of introducing flexibility, the organic part is induced with the inorganic part (flexible hybrid aerogels). Additionally, some more modern research is also available in the fabrication of hybrid flexible aerogels (based on organic-organic), the combination of two organic polymers. Moreover, a new type (single-component flexible aerogels) are quite a new category composed of only single materials; this category is very limited, charming to make the flexible aerogels pure from single polymers. The present review is composed of modern techniques and studies available to fabricate hybrid and single-component flexible aerogels. Their synthesis, factors affecting their parameters, and limitations associated with them are explained deeply. Moreover, a comparative analysis of drying methods and their effectiveness in the development of structures are described in detail. The further sections explain their properties and characterization methods. Eventually, their applications in a variety of multifunctional fields are covered. This article will support to introduce the roadmap pointing to a future direction in the production of the single-component flexible aerogel materials and their applications.

Formation of bis-azomethines from hydrazine and heterocyclic aromatic carbaldehydes, namely pyridine-2-carbaldehyde and pyrazine-2-carbaldehyde, is studied using density functional theory. The theoretical investigation is correlated with experimental results obtained by means of NMR spectroscopy. The presence of bis-hemiaminal intermediates is evidenced by NMR spectra while surprisingly stable hemiaminal intermediate was isolated experimentally. Water, methanol and acetic acid were outlined to play a crucial role as active catalysts of elementary steps of the reaction mechanisms. The possible reaction sequences, i.e. addition-dehydration-addition-dehydration or addition-addition-dehydration-dehydration are investigated and discussed. Also, alternative mechanistic path via ionic mechanism was proposed for the formation of hemiaminals., (© 2023. Springer Nature Limited.)

The formation of hemiacetals from pyrazine trifluoromethylketone as a model receptor and four simple alcohols was studied by using quantum chemical calculations and NMR spectroscopy. Free energy profiles for four types of mechanistic pathways were calculated and discussed with respect to kinetic and thermodynamic measurements. We show that hemiacetal formation is facilitated by an assisted proton transfer process via a pseudo eight-membered transition state which brings the theory and experiment into close agreement. Also, a newly proposed mechanistic pathway for hemiacetal formation via a five-membered transition state leading to zwitterionic intermediates is discussed. Direct proton transfer in a pseudo four-membered transition state can be ruled out due to the high energy of transition states with respect to other mechanistic pathways. We also show that in the case of hemiacetals, water and alcohol molecules cannot account sufficiently for the H-transfer process via six-membered transition states.

Novel nickel(ii) complexes bearing ( t butyl)bis(diphenylphosphanyl)amine and different halogenido ligands, [Ni(P,P)X 2 ] = [Ni{ t BuN(PPh 2 ) 2 -κ 2 P}X 2 ], (X = Cl, Br, I) are prepared, characterized by IR and NMR spectroscopy, mass spectrometry and X-ray crystallography, and tested as catalysts in the Kumada cross-coupling reaction of model substituted iodobenzenes and p -tolylmagnesium bromide. The data obtained together with DFT calculations indicate that these new catalysts operate in the Ni(i)-Ni(iii) mode. The highest catalytic activity and selectivity are exhibited by [Ni(P,P)Cl 2 ], which is most easily reduced by the used Grignard reagent to the Ni(i) state. This process is much more energy demanding in the case of the bromido and iodido complexes, causing the appearance of the induction period. [Ni(P,P)Cl 2 ] is also very active in the cross-couplings of substrates with iodine atoms sterically shielded by ortho substituents. The data obtained are in good accordance with the described positive effect of the increased electron-releasing power of N -substituents R' on the overall catalytic performance of [Ni{R'N(PPh 2 ) 2 -κ 2 P}X 2 ] complexes., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The term aerogel is used for unique solid-state structures composed of three-dimensional (3D) interconnected networks filled with a huge amount of air. These air-filled pores enhance the physicochemical properties and the structural characteristics in macroscale as well as integrate typical characteristics of aerogels, e.g., low density, high porosity and some specific properties of their constituents. These characteristics equip aerogels for highly sensitive and highly selective sensing and energy materials, e.g., biosensors, gas sensors, pressure and strain sensors, supercapacitors, catalysts and ion batteries, etc. In recent years, considerable research efforts are devoted towards the applications of aerogels and promising results have been achieved and reported. In this thematic issue, ground-breaking and recent advances in the field of biomedical, energy and sensing are presented and discussed in detail. In addition, some other perspectives and recent challenges for the synthesis of high performance and low-cost aerogels and their applications are also summarized.

Human activities have enormous impact on current biodiversity distribution across all spatial scales. Despite the numerous studies showing the difference between preserved and impaired sites, only little is known about the regional scale. Therefore, we selected four European regions differing in habitat conservation status (HCS) to explore if the variation in land snail communities reflects regional differences. We collected quantitative land snail samples at 169 isolated spring fen sites and measured environmental parameters. The species richness of habitat specialists expressed low variation and weak associations with local conditions in the two regions of adequate HCS, presumably because of their common occurrence throughout most sites. In contrast, the richness of matrix-derived species, i.e. predominantly habitat generalists, was highly variable in these two regions and also tightly associated with local conditions, especially moisture. In both the intermediate and the inadequate HCS region, these associations were much weaker as the fens are less extreme and allow for penetration of matrix-derived species. Population densities of Vertigo geyeri, an umbrella species internationally protected by the EU Habitats Directive, were highest in the two adequate HCS regions. Species composition was primarily controlled by moisture in the regions of adequate HCS, while in the remaining regions, those predictors that are less easily jeopardized by human impact, such as climate, water chemistry and terrain topography, gained importance. In the inadequate HCS region, none of the analysed predictors was associated with the main compositional gradient, suggesting a complete disruption of community-environment relationships. Our results suggest that the species richness and community responses to natural gradients might be substantially modified by human impact, although the effect of some other region-specific factors cannot be easily disentangled because of inevitably low number of studied regions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Calcareous fens represent an endangered type of peatlands, acting as refugia for stress-tolerant species in the currently changing landscapes. The resurveys across many regions have reported their recent disappearance or deterioration despite both the extreme habitat conditions (carbonate richness, presence of calcareous tufa, nutrient limitation, high water level) and conservation management. To test the stability of their biotic communities in different environmental and management configurations, we repeatedly sampled molluscs (terrestrial and aquatic), vascular plants, and bryophytes at 30 calcareous fens in the Inner Western Carpathians (Slovakia, Poland) after 13-17 years of warm summers and land-use changes. We found a small yet statistically significant effect of sampling period (old versus new survey) on the species composition of all three groups of organisms when the effect of various positions of sites along ecological gradients was controlled for. The compositional changes, interpreted with the help of Ellenberg Indicator Values, suggest an incipient succession towards grasslands and shrublands, driven by decreasing soil moisture and increasing nutrient availability. Although the number of habitat specialists did not change, the number of matrix-derived vascular plant and bryophyte species significantly increased, with six ubiquitous species of productive habitats being significantly more represented currently, while the richness of aquatic molluscs significantly decreased. Fens in which potentially strongly competitive plant species were less stressed because of less intense management and lower habitat extremity were more prone to such succession. There was no single factor that could predict the magnitude of composition changes; instead, tested factors were found to act synergistically. Conservation management was predominantly important for bryophytes, while extreme habitat conditions were predominantly important for terrestrial snails. We suggested a way how nature conservancy authorities can prioritise the management needs by applying an abiotic indicator system, with less environmentally extreme fens requiring more intense conservation management., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In this paper, we present the use of a disubstituted polyacetylene with high thermal stability and quantum yield as a fluorescence label for the identification, tracing, recycling, and eventually anti-counterfeiting applications of thermoplastics. A new method was developed for the dispersion of poly[1-phenyl-2-[p-(trimethylsilyl)phenyl]acetylene] (PTMSDPA) into polymer blends. For such purposes, four representative commodity plastics were selected, i.e., polypropylene, low-density polyethylene, poly(methyl methacrylate), and polylactide. Polymer recycling was mimicked by two reprocessing cycles of the material, which imparted intensive luminescence to the labelled polymer blends when excited by proper illumination. The concentration of the labelling polymer in the matrices was approximately a few tens ppm by weight. Luminescence was visible to the naked eye and survived the simulated recycling successfully. In addition, luminescence emission maxima were correlated with polymer polarity and glass transition temperature, showing a marked blueshift in luminescence emission maxima with the increase in processing temperature and time. This blueshift results from the dispersion of the labelling polymer into the labelled polymer matrix. During processing, the polyacetylene chains disentangled, thereby suppressing their intermolecular interactions. Moreover, shear forces imposed during viscous polymer melt mixing enforced conformational changes, which shortened the average conjugation length of PTMSDPA chain segments. Combined, these two mechanisms shift the luminescence of the probe from a solid- to a more solution-like state. Thus, PTMSDPA can be used as a luminescent probe for dispersion quality, polymer blend homogeneity, and processing history, in addition to the identification, tracing, and recycling of thermoplastics., Competing Interests: The authors declare no conflict of interest.

The chain coordination polymerization of (ethynylarene)carbaldehydes with unprotected carbaldehyde groups, namely ethynylbenzaldehydes, 1-ethynylbenzene-3,5-dicarboxaldehyde, and 3-[(4-ethynylphenyl)ethynyl]benzaldehyde, is reported for the first time. Polymerization is catalyzed with various Rh(I) catalysts and yields poly(arylacetylene)s with one or two pendant carbaldehyde groups per monomeric unit. Surprisingly, the carbaldehyde groups of the monomers do not inhibit the polymerization unlike the carbaldehyde group of unsubstituted benzaldehyde that acts as a strong inhibitor of Rh(I) catalyzed polymerization of arylacetylenes. The inhibition ability of carbaldehyde groups in (ethynylarene)carbaldehydes seems to be eliminated owing to a simultaneous presence of unsaturated ethynyl groups in (ethynylarene)carbaldehydes. The reactive carbaldehyde groups make poly[(ethynylarene)carbaldehyde]s promising for functional appreciation via various postpolymerization modifications. The introduction of photoluminescence or chirality to poly(ethynylbenzaldehyde)s via quantitative modification of their carbaldehyde groups in reaction with either photoluminescent or chiral primary amines under formation of the polymers with Schiff-base-type pendant groups is given as an example., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)