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Background
Spirochetes are the most abundant bacterial group in the hindgut of termites. The largest species, with cell lengths of up to 100 µm, have been provisionally classified in the family “ Pillotinaceae ” based exclusively on morphological traits. However, in the absence of cultured representatives, their phylogenetic position and metabolism remain entirely unknown.
Results
We investigated phylogeny and metabolic capacities of “pillotinaceous” spirochetes using single-cell techniques, electron microscopy, and fluorescence in situ hybridization. All sequences of large spirochetes obtained from various termites fell into four distinct, well-supported clusters within the family Breznakiellaceae. Based on ultrastructural features, three of the clusters were assigned to the genera Pillotina, Hollandina, and the newly established genus Hollandinoides; a fourth cluster was tentatively assigned to the genus Clevelandina . Functional analysis of the single-cell genomes of Pillotina corrugata sp. nov., Hollandina grandis sp. nov., and Hollandinoides gharagozlouae gen. nov. sp. nov., combined with comparative genomics of other uncultured relatives, demonstrated differences in the capacity to degrade cellulose, hemicelluloses, and dextrins. While members of the genus Pillotina have a fermentative metabolism, members of the other genera encode a Wood–Ljungdahl pathway and, in the case of Hollandina, a group-III nitrogenase, suggesting roles in reductive acetogenesis and nitrogen fixation.
Conclusions
Our results provide the first molecular data on pillotinaceous spirochetes. We show that the three genera covered in our study belong to the family Breznakiellaceae, which harbors the majority of termite-gut spirochetes. Comparative genome analysis indicated that the large spirochetes in termite guts have distinct roles in symbiotic digestion.
The current work comprises three stages. First, the self-catalyzed polycondensation (SCP) of glycolic acid (GA) was studied in bulk or in suspension at 190°C or at 205°C. Cyclic poly(glycolic acid)s, cPGAs, with number average molecular weights (Mn´s) up 6 700 g mol-1 and dispersities below 2.0 were obtained. These cPGAs possess an unusual molecular weight distribution with a considerable predominance of cycles having degrees of polymerization of 28, 32 and 36. The cycles were formed in the solid state under thermodynamic control which favors the formation of extended-ring crystals. These cPGAs are an off-white, brittle porous mass that is easy to grind, yielding a flowable, crystalline powder suitable for 3D printing with laser sintering (SLS). In the second stage, the influence of non-toxic catalysts such as, Mg, Zn, Ti, Sn(II), Zr and Bi salts or complexes was studied. Compared to the results obtained with self-catalyzed polycondensation in bulk, the best metal catalysts increased the molecular weight by a factor of two to three. However, when compared to the results obtained with self-catalysis in 1,2-dichlorobenzene, the increase was limited to approximately 20%. The third stage examined the influence of 4-toluene sulfonic acid (TSA), which was found to favor the formation of the most perfect crystals with crystallinities up to 84% and the highest reported melting temperatures (up to 245 °C). This indicates the existence of a high Tm morphology, analogous to that of polylactide. Small-angle X-ray scattering (SAXS) measurements indicate that significant growth in crystal thickness is mainly responsible for these effects.
The research and development of firesafe and sustainable polymer materials with appropriate mechanical properties for cable jacketing applications is addressed. Composites based on thermoplastic polyurethane (TPU) combining industrial-waste leather fibers and a commercial flame-retardant additive (ammonium polyphosphate – APP) are investigated. TPU composites were extruded under different temperature profiles and rotational speeds to obtain flame-retardant composites with appropriate mechanical properties. The detailed investigation of viscoelastic properties, morphology, tensile mechanical properties, pyrolysis, forced-flaming combustion and reaction to small flame highlights that applying optimized processing is key to producing TPU composites with the best tensile mechanical properties and flame retardancy. This finding was associated with the production of a highly elastic network, which was attributed to better dispersion and distribution of leather fibers and APP particles. TPU composites, combining 5 phr (parts per hundred resin) industrial-waste leather fibers and 5 phr APP, were compared to composites using 10 phr of APP. The same UL 94 V-0 classification, equal reduced fire risk (MARHE) with diminished smoke release, similar Young’s modulus and elongation at break, and improved tensile strength (20%) are achieved by replacing 50% APP with industrial-waste leather fibers; thus, the industrial-wastes leather fibers are simultaneously upcycled for this specific application.
Preparation workflows of fluorescent nm- and µm-sized polymer particles used as reporters in fluorescent assays, bioimaging, and sensing studies or calibration tools for fluorescence methods in the life sciences can be time-consuming and labor-intensive. Also, the outcome can be operator dependent. Here, we present simple and cost-efficient automated workflows for dye loading and surface labeling of polystyrene particles (PSP), using a commercial self-programmable pipetting robot. For developing and fine-tuning automated staining workflows, hydrophobic Nile Red (NR) was incorporated into 100 nm, 200 nm, and 1000 nm PSP by an adapted swelling procedure of premanufactured particles in the presence of hydrophobic dyes, thereby confirming its reliability and versatility. Subsequent expansion of our automation concept to the labeling of carboxylated PSP with pH-sensitive 6-aminofluorescein (6-AMF) and aminated PSP with pH-responsive fluorescein isocyanate (FITC) demonstrated its broad applicability. All automated workflows were optimized and validated by gravimetry and spectroscopic measurements with a microtiter plate (MTP) reader in absorption and fluorescence mode to ensure particle recovery and reproducible fluorescence features and determine PSP dye loading and labeling efficiencies. Comparison with the manual fabrication of NR-stained PSP using an established swelling protocol showed that our automation approach utilizing a pipetting robot considerably reduced the variability in particle recovery and dye loading efficiency. Overall, our simple, labor- and time-efficient workflows with inexpensive and broadly available commercial automation tools present attractive alternatives to manual particle loading and labeling and provide the basis for fast parameter screening, parallel processing, and decreased hands-on time.
The reconstruction of the thermal history of anthropogenic materials is crucial for understanding historical manufacturing techniques. Preparatory parameters such as firing temperature, heating and cooling rates, soaking time, and kiln atmosphere significantly affect the chemical and structural properties of the final product. Comparing historical materials with replicas produced under well-defined laboratory conditions helps identify indicators for these parameters. This comparative approach is greatly enhanced by spectroscopic analyses. Raman spectroscopy has proven to be a powerful tool in this field due to its high sensitivity to crystal-chemical alterations and high spatial resolution.
The results of thermal experiments with gypsum and carbonate raw materials at burning temperatures up to 1000 °C are presented. Precise measurements of Raman peak positions and Raman band widths enable the differentiation of chemically similar phases. Changes in the Raman band parameters are evident even after the subsequent hydration-hardening process of the fired samples, allowing the spectral discrimination of samples treated at different temperatures steps. These findings from the thermal experiments are further applied to Raman micro-spectroscopic mappings of medieval and reenacted mortars. The extracted Raman band parameters show comparable values between the experimental and real-life samples, proving Raman spectroscopy as a suitable tool for estimating the burning temperature and thus elucidating the manufacturing procedures of anthropogenic materials.
This work investigates the ability of occupants to escape from a battery electric vehicle during a thermal runaway of the traction battery initiated by nail penetration. Such events generate intense fires and large amounts of toxic gases, rapidly reducing the time available for safe evacuation. In controlled full-scale outdoor experiments on two identical mid-range battery electric vehicles, the smoke gas composition inside the cabin is examined. Using FTIR spectrometers and an oxygen analyzer, temporal and spatial concentrations of organic carbonates, hydrocarbons, hydrogen fluoride, hydrogen cyanide, acetylene, and oxygen are measured. Sampling locations include the driver's breathing zone, the right rear passenger's breathing zone, and the exterior right rear wheel housing. The study further evaluates occupant's escape capability using the fractional effective dose (FED) model in accordance with ISO 13571. Results show that toxic gases can reach harmful concentrations within minutes after smoke enters the cabin, though smoke entry times vary widely with fire progression. Differences in fire development and smoke dispersion strongly affect FED values and thus the time available for self-rescue. Overall, the findings provide an important basis for assessing occupant safety during battery electric vehicle fires and highlight the need for improved mitigation strategies.
Comprehensive Structure–Property Mapping of Tuned Mechanical Flexibility in Organic Cocrystals
(2026)
Mechanically flexible crystals offer unique opportunities for adaptive materials, yet predictive control over their responses remains a major challenge. Here, we present a chemically unified series of 4-nitrophenol-based cocrystals, cocrystallized with bipyridyl linkers of varied geometries, to systematically map structure–property relationships. Subtle variations in interplanar angles and intermolecular interactions, such as π–π stacking and hydrogen bonding, enable tuning of mechanical responses ranging from brittle fracture to different extents of elastic bending and plastic bending or twistability. This design differs from previous strategies that relied primarily on van der Waals interactions or halogen bonding to impart mechanical compliance to organic crystals. Structural analysis, supported by energy framework calculations, explains the divergent mechanical behaviors. Notably, the studied cocrystal series spans all four canonical structure–property quadrants, manifested through mechanical flexibility, photoluminescence activity, or both. This systematic and comparative study highlights the delicate interplay between molecular packing and supramolecular interactions, providing structure–property correlations that inform emerging design principles for multifunctional crystalline materials for targeted applications.
Recycling of Li-ion batteries (LiBs) for metal recovery has gained increasing attention in recent years. Batteries contain per- and polyfluoroalkyl substances (PFAS), however, their behaviour during battery recycling is still not well understood. This study aims to (i) characterise the presence of PFAS in LiBs black mass collected from various recycling factories in Australia, and (ii) investigate the fate of PFAS during the metal recovery process. The concentration of bis-perfluoromethanesulfonimide (bis-FMeSI) (C2) in the black mass was up to 51,000 µg kg−1. Other emerging and legacy PFAS were present, with concentrations varying from 0.1 to100 µg kg−1. The complementary analysis results of extractable organically bound fluorine and Fluorine K-edge X-ray adsorption near-edge structure indicates that the LiBs black mass mainly consists of bis-FMeSI (C2) and LiPF6 as the main PFAS analytes (40 – 80% fluorine equivalent), however other unknown PFAS may also be present. The long-chain PFAS are more difficult to leach compared to the short-chain PFAS. H2SO4 leaches 58% bis-FMeSI which is the highest compared to HNO3 (51%) and HCl (40.4%). During the precipitation stage, adding H2O2 to the H2SO4 (5% v/v) leaching agent increased bis-FMeSI adsorption onto metal precipitates by 40%. Using PiFM analysis, PFAS are found predominantly present as surface-associated species within binder- and carbon-rich domains, and the leaching mechanism is strongly attributable to the disruption of these surface-accessible phases. This work constructs the first baseline for the relevant research about the trade-off between metal recovery and PFAS pollutants in the LiBs recycling process.
The use of different nanoparticles (NPs) is increasing in a wide variety of everyday products. Nevertheless, most studies concerning NP risk assessment have evaluated exposure scenarios involving a single kind of NP. A stepwise study distinguishing between the effects resulting from exposure to one kind of NP and those resulting from different co-exposure scenarios to Al2O3 and CeO2 NPs at concentrations below acute toxicity was conducted with different analytical techniques. As a starting point, WST-1 viability assays were performed to assess whether the chosen exposure concentrations resulted in any acute loss of viability, which would hamper further insight into the cellular response to NP exposure. Then, data on NP dissolution and uptake were obtained via single-particle inductively coupled plasma–mass spectrometry (spICP-MS) and microwave-assisted ICP-MS. Additionally, time-of-flight secondary ion mass spectrometry (ToF-SIMS) was performed to check for differences in the biological response to the exposure scenarios at the single-cell level. It was found that the proposed combined techniques provide insight into changes in biological responses as well as cellular metal contents among the exposure scenarios. In this work, a comprehensive tiered analytical strategy for evaluating the biological responses to challenging exposure scenarios is provided. The results highlight the necessity of selecting situations more closely resembling real life—including concentrations below acute toxicity and potential interactions due to multiple NPs—when estimating potential health risks. These findings thus provide a foundation and an incentive for further research into the complex processes leading to the observed effects.