[Tl7]7- Clusters in Mixed Alkali Metal Thallides Cs7.29K5.71Tl13 and Cs3.45K3.55Tl7.

Investigations in the ternary system Cs-K-Tl resulted in the unexpected formation of new ternary thallides Cs7.29K5.71Tl13 and Cs3.45K3.55Tl7. Single crystal X-ray structure analyses of both compounds reveal the presence of isolated Tl cluster units. Cs7.29K5.71Tl13 crystallizes in the monoclinic space group C2/c (a = 30.7792(9) Å, b = 11.000(2) Å, c = 14.0291(4) Å, ß = 112.676(4)°, Z = 4) and contains [Tl6]6- and [Tl7]7- clusters as thallium subunits. Cs3.45K3.55Tl7 crystallizes in the tetragonal space group I41/a (a = 13.6177(2) Å, c = 25.5573(8) Å, Z = 8) and contains [Tl7]7- clusters exclusively. The formation of Cs7.29K5.71Tl13 is obtained after slow cooling in addition to that of Cs3.45K3.55Tl7 and can be suppressed by quenching the stoichiometric mixture. First dissolution experiments in liquid ammonia suggest thallium and amide as final oxidation products. Full relativistic band structure calculations of Cs4K3Tl7 and Cs8K5Tl13 showed a (pseudo) band gap around EF for both compounds.

Turning Seashell Waste into Electrically Conductive Particles.

Biomaterials such as seashells are intriguing due to their remarkable properties, including their hierarchical structure from the nanometer to the micro- or even macroscopic scale. Transferring this nanostructure to generate nanostructured polymers can improve their electrical conductivity. Here, we present the synthesis of polypyrrole using waste seashell powder as a template to prepare a polypyrrole/CaCO3 composite material. Various synthesis parameters were optimized to produce a composite material with an electrical conductivity of 2.1 × 10-4 ± 3.2 × 10-5 S/cm. This work presents the transformation of waste seashells into sustainable, electronically conductive materials and their application as an antistatic agent in polymers. The requirements of an antistatic material were met for a safety shoe sole.

Elusive Zintl Ions [µ-HSi4 ]3- and [Si5 ]2- in Liquid Ammonia: Protonation States, Sites, and Bonding Situation Evaluated by NMR and Theory.

The existence of [µ-HSi4 ]3- in liquid ammonia solutions is confirmed by 1 H and 29 Si NMR experiments. Both NMR and quantum chemical calculations reveal that the H atom bridges two Si atoms of the [Si4 ]4- cluster, contrary to the expectation that it is located at one vertex Si of the tetrahedron. The calculations also indicate that in the formation of [µ-HSi4 ]3- , protonation is driven by a high charge density and an increase of electron delocalization compared to [Si4 ]4- . Additionally, [Si5 ]2- was detected for the first time and characterized by NMR. Calculations show that it is resistant to protonation, owing to a strong charge delocalization, which is significantly reduced upon protonation. Thus, our methods reveal three silicides in liquid ammonia: unprotonated [Si5 ]2- , terminally protonated [HSi9 ]3- , and bridge-protonated [µ-HSi4 ]3- . The protonation trend can be roughly predicted by the difference in charge delocalization between the parent compound and the product, which can be finely tuned by the presence of counter ions in solution.

The Structure of [HSi9 ]3- in the Solid State and Its Unexpected Highly Dynamic Behavior in Solution.

We report on the first unambiguous detection of the elusive [HSi9 ]3- anion in solutions of liquid ammonia by various 29 Si and 1 H NMR experiments including chemical exchange saturation transfer (CEST). The characteristic multiplicity patterns of both the 29 Si and 1 H resonances together with CEST and a partially reduced 1 H,29 Si coupling constant indicate the presence of a highly dynamic Si8 entity and a Si-H moiety with slow proton hopping. Theoretical calculations corroborate both reorganization of Si8 on the picosecond timescale via low vibrational modes and proton hopping. In addition, in a single-crystal X-ray study of (K(DB[18]crown-6))(K([2.2.2]crypt))2 [HSi9 ]⋅8.5 NH3 , the H atom was unequivocally localized at one vertex of the basal square of the monocapped square-antiprismatic cluster. Thus experimental studies and theoretical considerations provide unprecedented insight into both the structure and the dynamic behavior of these cluster anions, which hitherto had been considered to be rigid.

Selective P4 Activation by a Highly Reduced Cobaltate: Synthesis of Dicobalt Tetraphosphido Complexes.

Although the chemistry of transition metal polyphosphide anions has attracted significant attention, there are few reports of studies in which such species have been synthesized directly from white phosphorus. [K(OEt2 )2 {Co(BIAN)(cod)}] (1, BIAN=1,2-bis(2,6-diisopropylphenylimino)acenaphthene, cod=1,5-cyclooctadiene), which is readily prepared by ligand exchange from [K(thf)x {Co(cod)2 }], reacts with P4 to afford [{K(thf)}2 {(BIAN)Co}2 (µ-η4 :η4 -P4 )] (2 a) in 61 % yield (isolated product). [{K(OEt2 )}2 {(BIAN)Co}2 (µ-η4 :η4 -P4 )] (2 b) and [K([18]crown-6)(MeCN)]2 [{(BIAN)Co}2 (µ-η4 :η4 -P4 )] (2 c) were obtained by recrystallizing 2 a from diethyl ether and acetonitrile (and using [18]crown-6 in case of 2 c). Oxidation of 2 a with [Cp2 Fe]BArF4 (one equivalent) and subsequent recrystallization of the product from different solvents gave [K(OEt2 ){(BIAN)Co}2 (µ-η4 :η4 -P4 )] (3 a) and [K(dme)4 ][{(BIAN)Co}2 (µ-η4 :η4 -P4 )] (3 b; dme=1,2-dimethoxyethane). Neutral [{(BIAN)Co}2 (µ-η4 :η4 -P4 )] (4) was obtained in moderate yield by oxidizing 2 a with two equivalents of [Cp2 Fe]BArF4 . The new complexes were characterized by NMR, EPR (in the case of 3 a), and UV/Vis spectroscopy, and elemental analysis. The molecular structures revealed by X-ray crystallography display planar cyclic or open-chain P44- units sandwiched between {(BIAN)Co} fragments.

Environmental drivers of Ixodes ricinus abundance in forest fragments of rural European landscapes.

BACKGROUND: The castor bean tick (Ixodes ricinus) transmits infectious diseases such as Lyme borreliosis, which constitutes an important ecosystem disservice. Despite many local studies, a comprehensive understanding of the key drivers of tick abundance at the continental scale is still lacking. We analyze a large set of environmental factors as potential drivers of I. ricinus abundance. Our multi-scale study was carried out in deciduous forest fragments dispersed within two contrasting rural landscapes of eight regions, along a macroclimatic gradient stretching from southern France to central Sweden and Estonia. We surveyed the abundance of I. ricinus, plant community composition, forest structure and soil properties and compiled data on landscape structure, macroclimate and habitat properties. We used linear mixed models to analyze patterns and derived the relative importance of the significant drivers. RESULTS: Many drivers had, on their own, either a moderate or small explanatory value for the abundance of I. ricinus, but combined they explained a substantial part of variation. This emphasizes the complex ecology of I. ricinus and the relevance of environmental factors for tick abundance. Macroclimate only explained a small fraction of variation, while properties of macro- and microhabitat, which buffer macroclimate, had a considerable impact on tick abundance. The amount of forest and the composition of the surrounding rural landscape were additionally important drivers of tick abundance. Functional (dispersules) and structural (density of tree and shrub layers) properties of the habitat patch played an important role. Various diversity metrics had only a small relative importance. Ontogenetic tick stages showed pronounced differences in their response. The abundance of nymphs and adults is explained by the preceding stage with a positive relationship, indicating a cumulative effect of drivers. CONCLUSIONS: Our findings suggest that the ecosystem disservices of tick-borne diseases, via the abundance of ticks, strongly depends on habitat properties and thus on how humans manage ecosystems from the scale of the microhabitat to the landscape. This study stresses the need to further evaluate the interaction between climate change and ecosystem management on I. ricinus abundance.

Molecular design of recombinant scFv antibodies for site-specific photocoupling to ß-cyclodextrin in solution and onto solid support.

The ability to design and tailor-make antibodies to meet the biophysical demands required by the vast range of current and future antibody-based applications within biotechnology and biomedicine will be essential. In this proof-of-concept study, we have for the first time tailored human recombinant scFv antibodies for site-specific photocoupling through the use of an unnatural amino acid (UAA) and the dock'n'flash technology. In more detail, we have successfully explored the possibility to expand the genetic code of E. coli and introduced the photoreactive UAA p-benzoyl-L-phenylalanine (pBpa), and showed that the mutated scFv antibody could be expressed in E. coli with retained structural and functional properties, as well as binding affinity. The pBpa group was then used for affinity capture of the mutated antibody by ß-cyclodextrin (ß-CD), which provided the hydrogen atoms to be abstracted in the subsequent photocoupling process upon irradiation at 365nm. The results showed that the pBpa mutated antibody could be site-specifically photocoupled to free and surface (array) immobilized ß-CD. Taken together, this paves the way for novel means of tailoring recombinant scFv antibodies for site-specific photochemical-based tagging, functionalization and immobilization in numerous applications.

Stability and Conversion of Tin Zintl Anions in Liquid Ammonia Investigated by NMR spectroscopy.

Homoatomic polyanions of post-transition main-group metals, namely, Zintl anions, are precast in analogous Zintl phases and can react in solution to form new materials. Despite comprehensible reaction approaches, the formed products cannot be planned in advance, as hitherto undetected and therefore disregarded side reactions take place. The outcomes and interpretations of the reactions of Zintl anions are so far based mainly on crystal structures, which only allow characterization of the product that has the lowest solubility. Here we present the results of our investigation of the stability of highly charged tin Zintl anions in liquid ammonia, which is not exclusively based on solution effects but also on the oxidative influence of the solvent. This allows for a deeper understanding of the ongoing processes in solution and opens doors to the directed synthesis of transition metal complexes of Sn4 (4-) , here shown by its reactivity towards MesCu.

Polyclonal murine and rabbit antibodies for the bile acid isolithocholic acid.

Bile acids are relevant markers for clinical research. This study reports the production of antibodies for isolithocholic acid, the isomer of the extensively studied lithocholic acid. The IgG titer and affinity maturation were monitored during the immunizations of three mice and two rabbits. In both animal models, polyclonal antibodies with a high selectivity and affinity were produced. The development of a direct competitive ELISA with a test midpoint of 0.69 ± 0.05 µ g/L and a measurement range from 0.09-15 µg/L is reported. Additionally, the crystal structure of isolithocholic acid is described for the first time.

Reintroduced Sumatran orangutans (Pongo abelii): using major food tree species as indicators of habitat suitability.

Reintroducing orangutans (Pongo spp.) into the wild requires a suitable, secure habitat. To identify acceptable areas for their reintroduction and define priority conservation sites, we analysed the tree species composition in the Bukit Tigapuluh ecosystem in Jambi, Sumatra. We used this information to determine the distribution patterns of those species that represent an essential part of the diet of reintroduced orangutans. Important orangutan food tree species showed significant differences in composition, frequency and abundance among topographic forest types and recovered selectively logged and unlogged forests. Riparian forests and recovered selectively logged areas offered a vegetation composition and forest structure most suitable for the reintroduction of orangutans and showed numerous important tree species that serve as indicator species, i.e. species growing predominantly or exclusively in a specific forest type. © 2014 S. Karger AG, Basel.

About the polymorphism of [Li(C4H8O)3]I: crystal structures of trigonal and tetra-gonal polymorphs.

Two new trigonal and tetra-gonal polymorphs of the title compound, iodido-tris-(tetra-hydro-furan-κO)lithium, are presented, which both include the isolated ion pair Li(THF)3 (+)·I(-). One Li-I ion contact and three tetra-hydro-furan (THF) mol-ecules complete the tetra-hedral coordination of the lithium cation. The three-dimensional arrangement in the two polymorphs differs notably. In the trigonal structure, the ion pair is located on a threefold rotation axis of space group P-3 and only one THF mol-ecule is present in the asymmetric unit. In the crystal, strands of ion pairs parallel to [001] are observed with an eclipsed conformation of the THF mol-ecules relative to the Li⋯I axis of two adjacent ion pairs. In contrast, the tetra-gonal polymorph shows a much larger unit cell in which all atoms are located on general positions of the space group I41 cd. The resulting three-dimensional arrangement shows helical chains of ion pairs parallel to [001]. Apart from van der Waals contacts, no remarkable inter-molecular forces are present between the isolated ion pairs in both structures.

Stearate-Coated Biogenic Calcium Carbonate from Waste Seashells: A Sustainable Plastic Filler.

Waste seashells from aquaculture are a massive source of biogenic calcium carbonate (bCC) that can be a potential substitute for ground calcium carbonate and precipitated calcium carbonate. These last materials find several applications in industry after a surface coating with hydrophobic molecules, with stearate as the most used. Here, we investigate for the first time the capability of aqueous stearate dispersions to coat bCC powders from seashells of market-relevant mollusc aquaculture species, namely the oyster Crassostrea gigas, the scallop Pecten jacobaeus, and the clam Chamelea gallina. The chemical-physical features of bCC were extensively characterized by different analytical techniques. The results of stearate adsorption experiments showed that the oyster shell powder, which is the bCC with a higher content of the organic matrix, showed the highest adsorption capability (about 23 wt % compared to 10 wt % of geogenic calcite). These results agree with the mechanism proposed in the literature in which stearate adsorption mainly involves the formation of calcium stearate micelles in the dispersion before the physical adsorption. The coated bCC from oyster shells was also tested as fillers in an ethylene vinyl acetate compound used for the preparation of shoe soles. The obtained compound showed better mechanical performance than the one prepared using ground calcium. In conclusion, we can state that bCC can replace ground and precipitated calcium carbonate and has a higher stearate adsorbing capability. Moreover, they represent an environmentally friendly and sustainable source of calcium carbonate that organisms produce by high biological control over composition, polymorphism, and crystal texture. These features can be exploited for applications in fields where calcium carbonate with selected features is required.

Delivery of multiple transgenes to plant cells by an improved version of MultiRound Gateway technology.

At present, only few methods for the effective assembly of multigene constructs have been described. Here we present an improved version of the MultiRound Gateway technology, which facilitates plant multigene transformation. The system consists of two attL-flanked entry vectors, which contain an attR cassette, and a transformation-competent artificial chromosome based destination vector. By alternate use of the two entry vectors, multiple transgenes can be delivered sequentially into the Gateway-compatible destination vector. Multigene constructs that carried up to seven transgenes corresponding to more than 26 kb were assembled by seven rounds of LR recombination. The constructs were successfully transformed into tobacco plants and were stably inherited for at least two generations. Thus, our system represents a powerful, highly efficient tool for multigene plant transformation and may facilitate genetic engineering of agronomic traits or the assembly of genetic pathways for the production of biofuels, industrial or pharmaceutical compounds in plants.

Fenugreek seed affects intestinal microbiota and immunological variables in piglets after weaning.

Fenugreek seed has been shown to affect the intestinal microbiota and immunological responses in animals. A feeding trial with male castrated piglets was performed over 28 d without or with the addition of 1·5 g fenugreek seeds/kg complete diet in ten and eleven piglets, weaned at 21 d. In the intestinal tract, pH, lactate and SCFA were measured as major bacterial metabolites. Immune cell phenotypes, phagocytic activity and lymphocyte proliferation after stimulation with pokeweed mitogen, concanavalin A and phytohaemagglutinin M were measured by flow cytometry. Health status and performance of the piglets were not affected by fenugreek. The pH in the caecum and colon were reduced compared with the control (P< 0·05). Higher concentrations of l-lactic acid were recorded in the small-intestinal digesta (average concentrations from the duodenum, jejunum and ileum; P< 0·05), while the concentrations of SCFA remained unchanged except an increase in n-butyric acid in colon contents (P< 0·05). The piglets fed the fenugreek diet had higher Lactobacillus and clostridium cluster I concentrations and lower Escherichia, Hafnia and Shigella concentrations in the small intestine. The addition of fenugreek increased the relative concentration of the γδ T-cell population (TCR1+CD8α-) in the blood with a simultaneous reduction of antigen-presenting cells (MHCII+CD5-) (P< 0·05). Proliferation rate and phagocytosis activity of monocytes were not affected by the additive. In conclusion, fenugreek seeds might be interesting as a feed ingredient for young piglets due to their effects on the intestinal microbiota and immunological variables. The impact on performance and animal health has to be further evaluated.

Enhancing structural complexity: An experiment conducted in the Black Forest National Park, Germany.

We report on a structural complexity enhancement (SCE) experiment that was designed to test ecological restoration measures in the Black Forest National Park, Germany. The main goal was to understand as to whether the creation of standing and downed deadwood within previously managed, single-layered Norway spruce (Picea abies L.) forests accelerates the development of forest structure, richness, and diversity of a range of taxonomic groups. Here we introduce the experimental design and describe the development of stand structure including abundance and richness of tree-related microhabitats (TreMs) within 5 years after initiation of the experiment in October 2016. To enhance structural complexity in treatment plots, 10 trees per plot were toppled using a skidder winch, and another 10 trees were ring barked at a height of around 60 cm above ground level with a chainsaw. To monitor stand structure, we collected data on common forest attributes such as diameter at breast height (DBH), tree height, and TreMs of all trees in the six experimental and six control plots measuring 0.25 ha in size before the treatments were carried out in 2016 and again in 2020/21. We analyzed the abundance and richness of TreMs using generalized linear mixed models with DBH and treatment vs. control as predictors. The SCE treatment resulted in a significant increase in deadwood volumes (4.2 vs. 439.5 m3) as well as in TreM abundance and richness (increase of 0.74 TreMs per tree). This indicates that the SCE treatment was effective to increase biodiversity-relevant structures such as deadwood and TreMs, in previously managed Norway spruce-dominated stands. The ongoing monitoring of a range of taxonomic groups (birds, bats, small mammals, coleoptera, fungi, mosses, and vascular plants) in this experiment will demonstrate to what extent the enhancement in structural complexity will lead to an enrichment in species richness and diversity.

A sustainable one-pot method to transform seashell waste calcium carbonate to osteoinductive hydroxyapatite micro-nanoparticles.

We have developed a straightforward, one-pot, low-temperature hydrothermal method to transform oyster shell waste particles (bCCP) from the species Crassostrea gigas (Mg-calcite, 5 wt% Mg) into hydroxyapatite (HA) micro/nanoparticles. The influence of the P reagents (H3PO4, KH2PO4, and K2HPO4), P/bCCP molar ratios (0.24, 0.6, and 0.96), digestion temperatures (25-200 °C), and digestion times (1 week-2 months) on the transformation process was thoroughly investigated. At 1 week, the minimum temperature to yield the full transformation significantly reduced from 160 °C to 120 °C when using K2HPO4 instead of KH2PO4 at a P/bCCP ratio of 0.6, and even to 80 °C at a P/bCCP ratio of 0.96. The transformation took place via a dissolution-reprecipitation mechanism driven by the favorable balance between HA precipitation and bCCP dissolution, due to the lower solubility product of HA than that of calcite at any of the tested temperatures. Both the bCCP and the derived HA particles were cytocompatible for MG-63 human osteosarcoma cells and m17.ASC murine mesenchymal stem cells, and additionally, they promoted the osteogenic differentiation of m17.ASC, especially the HA particles. Because of their physicochemical features and biological compatibility, both particles could be useful osteoinductive platforms for translational applications in bone tissue engineering.

Recovering and Exploiting Aragonite and Calcite Single Crystals with Biologically Controlled Shapes from Mussel Shells.

Control over the shape and morphology of single crystals is a theme of great interest in fundamental science and for technological application. Many synthetic strategies to achieve this goal are inspired by biomineralization processes. Indeed, organisms are able to produce crystals with high fidelity in shape and morphology utilizing macromolecules that act as modifiers. An alternative strategy can be the recovery of crystals from biomineralization products, in this case, seashells. In particular, waste mussel shells from aquaculture are considered. They are mainly built up of single crystals of calcite fibers and aragonite tablets forming an outer and an inner layer, respectively. A simple mechanochemical treatment has been developed to separate and recover these two typologies of single crystals. The characterization of these single crystals showed peculiar properties with respect to the calcium carbonate from quarry or synthesis. We exploited these biomaterials in the water remediation field using them as substrate adsorbing dyes. We found that these substrates show a high capability of adsorption for anionic dye, such as Eosin Y, but a low capability of adsorption for cationic dyes, such as Blue Methylene. The adsorption was reversible at pH 5.6. This application represents just an example of the potential use of these biogenic single crystals. We also envision potential applications as reinforcing fillers and optical devices.

The Role of Different Alkali Metals in the A15Tl27 Type Structure and the Synthesis and X-ray Structure Analysis of a New Substitutional Variant Cs14.53Tl28.4.

Alkali metal thallides have been known since the report of E. Zintl on NaTl in 1932. Subsequently, binary and ternary thallides of alkali metals have been characterized. At an alkali metal proportion of approximately 33% (A:Tl~1:2, A = alkali metal), three different unique type structures are reported: K49Tl108, Rb17Tl41 and A15Tl27 (A = Rb, Cs). Whereas Rb17Tl41 and K49Tl108 feature a three-dimensional sublattice of Tl atoms, the A15Tl27 structure type includes isolated Tl11 clusters as well as two-dimensional Tl-layers. This unique arrangement is only known so far when the heavier alkali metals Rb and Cs are included. In our contribution, we present single-crystal X-ray structure analyses of new ternary and quaternary compounds of the A15Tl27 type structure, which include different amounts of potassium. The crystal structures allow for the discussion of the favored alkali metal for each of the four Wyckoff positions and clearly demonstrate alkali metal dependent site preferences. Thereby, the compound Cs2.27K12.73Tl27 unambiguously proves the possibility of a potassium-rich A15Tl27 phase, even though a small amount of cesium appears to be needed for the stabilization of the latter structure type. Furthermore, we also present two compounds that show an embedding of Tl instead of alkali metal into the two-dimensional substructure, being equivalent to the formal oxidation of the latter. Cs14.53Tl28.4 represents the binary compound with the so far largest proportion of incorporated Tl in the structure type A15Tl27.

Evaluating the effectiveness of retention forestry to enhance biodiversity in production forests of Central Europe using an interdisciplinary, multi-scale approach.

Retention forestry, which retains a portion of the original stand at the time of harvesting to maintain continuity of structural and compositional diversity, has been originally developed to mitigate the impacts of clear-cutting. Retention of habitat trees and deadwood has since become common practice also in continuous-cover forests of Central Europe. While the use of retention in these forests is plausible, the evidence base for its application is lacking, trade-offs have not been quantified, it is not clear what support it receives from forest owners and other stakeholders and how it is best integrated into forest management practices. The Research Training Group ConFoBi (Conservation of Forest Biodiversity in Multiple-use Landscapes of Central Europe) focusses on the effectiveness of retention forestry, combining ecological studies on forest biodiversity with social and economic studies of biodiversity conservation across multiple spatial scales. The aim of ConFoBi is to assess whether and how structural retention measures are appropriate for the conservation of forest biodiversity in uneven-aged and selectively harvested continuous-cover forests of temperate Europe. The study design is based on a pool of 135 plots (1 ha) distributed along gradients of forest connectivity and structure. The main objectives are (a) to investigate the effects of structural elements and landscape context on multiple taxa, including different trophic and functional groups, to evaluate the effectiveness of retention practices for biodiversity conservation; (b) to analyze how forest biodiversity conservation is perceived and practiced, and what costs and benefits it creates; and (c) to identify how biodiversity conservation can be effectively integrated in multi-functional forest management. ConFoBi will quantify retention levels required across the landscape, as well as the socio-economic prerequisites for their implementation by forest owners and managers. ConFoBi's research results will provide an evidence base for integrating biodiversity conservation into forest management in temperate forests.

Synthesis of the Tetragonal Phase of Zintl's NaTl and Its Structure Determination from Powder Diffraction Data.

A tetragonal distortion of the long-time known NaTl structure at 298 K was observed in different experimental setups, including Zintl's original procedure of reducing Tl(I)-iodide by sodium liquid ammonia solutions. The powder diffraction pattern obtained by the high temperature synthesis using classical solid-state techniques allowed a model-independent unambiguous structure solution and refinement of tetragonal distorted NaTl (Rp = 0.0179, wRp = 0.0246, R = 0.0477, wR = 0.0527, GooF = 1.24).