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This study investigates the influence of ambient humidity on the temperature sensitivity, measurement accuracy, and uncertainty of optical fibers with different coatings, using a Rayleigh-based distributed sensing technique. Polymer-coated fibers (acrylate and polyimide) and metal-coated fibers (copper and gold) were tested under controlled humidity (30%–90% RH) and temperature (20–60 °C) conditions. Rayleigh-based measurements revealed a slight but consistent decrease in temperature sensitivity with increasing humidity for all polymer-coated fibers, attributed to humidity-induced changes in coating stiffness and strain transfer. In contrast, metal-coated fibers exhibited humidity-independent behavior and superior stability. These findings highlight the non-negligible role of ambient humidity in fiber-optic temperature sensing, particularly in Rayleigh-based systems using hygroscopic coatings. The results provide practical guidance for fiber and coating selection in humid environments and offer broader insight into humidity–strain–temperature coupling mechanisms relevant to other fiber-optic sensing mechanisms.
We assessed the quantification of surface amino functional groups (FGs) for a large set of commercial and custom-made aminated silica nanoparticles (SiO2 NPs) with sizes of 20–100 nm, prepared with different sol–gel routes, different amounts of surface amino FGs, and different porosity with four methods providing different, yet connected measurands in a bilateral study of two laboratories, BAM and NRC, with the overall aim to develop standardizable measurements for surface FG quantification. Special emphasis was dedicated to traceable quantitative magnetic resonance spectroscopy (qNMR) performed with dissolved SiO2 NPs. For the cost efficient and automatable screening of the amount of surface amino FGs done in a first step of this study, the optical fluorescamine assay and a potentiometric titration method were utilized by one partner, i.e., BAM, yielding the amount of primary amino FGs accessible for the reaction with a dye precursor and the total amount of (de)protonatable FGs. These measurements, which give estimates of the minimum and maximum number of surface amino FGs, laid the basis for quantifying the amount of amino silane molecules with chemo-selective qNMR with stepwise fine-tuned workflows, involving centrifugation, drying, weighting, dissolution, measurement, and data evaluation steps jointly performed by BAM and NRC. Data comparability and relative standard deviations (RSDs) obtained by both labs were used as quality measures for method optimization and as prerequisites to identify method-inherent limitations to be later considered for standardized measurement protocols. Additionally, the nitrogen (N) to silicon (Si) ratio in the near-surface region of the SiO2 NPs was determined by both labs using X-ray photoelectron spectroscopy (XPS), a well established surface sensitive analytical method increasingly utilized for microparticles and nano-objects which is currently also in the focus of international standardization activities. Overall, our results underline the importance of multi-method characterization studies for quantifying FGs on NMs involving at least two expert laboratories for effectively identifying sources of uncertainty, validating analytical methods, and deriving NM structure–property relationships.
Cadmium is a heavy metal that can be hazardous to environmental and human health, even in trace levels.[1] In this way, the extraction and/or preconcentration of this element from environmental samples, such as river water, is important to obtain information about the composition and monitoring of potential contamination.[2] High-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS) is widely used for Cd determination. However, the determination of this element at trace-level can be challenging, especially in complex matrices. Thus, nanoparticles (NPs) can be used as an alternative for the extraction and preconcentration of Cd in environmental samples, minimizing the potential interferences and improving the method´s limit of detection (LOD). Considering that Pd is also widely used as a “universal” chemical modifier, this project aims todevelop PdNPs capped with 3-mercaptopropionic acid (MPA) to assess its potential as a chemical modifier and preconcentration agent for Cd determination by HR-CS GF AAS in river water. In this way, the synthesis of PdNPs was performed in an aqueous medium by using ascorbic acid as a reducing agent. The characterization of PdNPs was performed by checking the size via dynamic light scattering (DLS), transmission electron microscopy (TEM), and inductively coupled plasma mass spectrometer in single particle mode (spICP-MS), where the median size was 56 ± 14 nm. The temperature program of HR-CS GFAAS was optimized for river water under three conditions: using Pd(NO3)2/Mg2+ (0.01%/0.5% m/v) as a chemical modifier (condition A), using Pd NPs as a chemical modifier (condition B), and without chemical modifiers (condition C). The pyrolysis and atomization temperatures for condition A were 900 and 1900 ºC, for condition B were 700 ºC and 1900 ºC, and for condition C were 500 and 1900ºC, respectively. Besides the temperature of pyrolysis for the universal chemical modifier being higher than that of PdNPs, using the PdNPs, the absorbance is significantly greater, according to the t-test for pairs, at a 95% confidence level. In addition, the evaluation of the preconcentration property of the PdNP was performed by adding 1 µg L-1 of Cd2+ in buffer pH 4 in two systems: one with and the other without PdNPs. After 1 h of stirring, both
systems were centrifuged at 3600 rpm for 10 min, and the absorbance in HR-CS GFAAS for Cd in both supernatants was evaluated. According to ANOVA from the t-test, at a 95% confidence level, there was a significant difference in the absorbance, indicating that Cd is interacting with the PdNPs. A multifactorial planning 2k, where k is the number of parameters of the extraction, which was time of extraction (10; 35; 60 min), Volume of Pd NPs (100; 300; 500 µL), pH (3; 5; 7), was used to evaluate the parameters with significant influence in the preconcentration of Cd2+. According to ANOVA, with 95% confidence, there is no lack of fit, and the parameters volume of PdNP and pH significantly influenced the response. In this way, the Doehlert methodology surface will be applied to both significant parameters. The goal is to achieve optimal conditions that increase the extraction efficiency of Cd2+ from environmental samples. The results indicate that the developed material is promising to use as a chemical modifier and for the preconcentration of Cd2+ in environmental samples.
The presentation summarizes the 1H NMR relaxation pinciple for the nondestructive material characterization of building materials. We explain the basic principle of NMR and showcase 3 application cases: 1) Moisture transport and 2) In-situ pore size characteriztaion of buildiing materials and 3) Hydration characteristics of new, more climate friendly cementitious binders and mortars.
Immunity plays an important role in evolutionary ecology. The immune system interacts with both pathogens, which can act as important selective forces, and symbionts, which are regulated by the host‘s immune system and also can play a role in the host‘s immune defenses.
The Blattodea consist of what is commonly known as cockroaches and the termites, who are themselves specialized eusocial cockroaches. Blattodea have two symbiont types that are characteristic to either the cockroaches or the termites (Table 1). These symbiont transitions open up the opportunity to characterize and investigate host-symbiont-pathogen interactions and how they evolved in Blattodea.
Immunity plays an important role in evolutionary ecology. The immune system interacts with both pathogens, which can act as important selective forces, and symbionts, which are regulated by the host‘s immune system and can also play a role in the host‘s immune defenses.
The Blattodea consist of what is commonly known as cockroaches and the termites, who are themselves specialized eusocial cockroaches. Blattodea have two symbiont types that are characteristic to either the cockroaches or the termites (Table 1). These symbiont transitions open up the opportunity to characterize and investigate host-symbiont-pathogen interactions and how they evolved in Blattodea.
This paper presents digital quality infrastructure methods for hydrogen refueling stations using the Asset Administration Shell as a standardized digital twin. Implemented at BAM’s test platform, it integrates real-time sensor data, calibration certificates, and compliance documents to support traceable, interoperable asset management. In combination with AI and semantic tools, the system will enable predictive maintenance, remote audits, and improved safety. This approach reduces downtime, enhances transparency, and offers a scalable model demonstrating the potential of digital twins in advancing metrological traceability and operational efficiency in hydrogen technologies.
Nar1 is an essential eukaryotic protein proposed to function as an iron–sulphur (Fe/S) cluster trafficking factor in the cytosolic iron–sulphur protein assembly (CIA) machinery. However, such a role has remained unclear due to difficulties in purifying adequate amounts of cofactor-bound protein. The [FeFe]-hydrogenase-like protein has two conserved binding sites for [4Fe–4S] clusters but does not show hydrogenase activity in vivo due to the lack of an active site [2Fe]H cofactor. Here, we report a new preparation procedure for Nar1 that facilitated studies by UV-vis, EPR, and Mössbauer spectroscopies, along with native mass spectrometry. Nar1 recombinantly produced in E. coli contained a [4Fe–4S] cluster, bound presumably at site 1, along with an unexpected [2Fe–2S] cluster bound at an unknown site. Fe/S reconstitution reactions installed a second [4Fe–4S] cluster at site 2, leading to protein with up to three Fe/S cofactors. It is proposed that the [2Fe–2S] cluster occupies a cavity in Nar1 that is filled by the [2Fe]H cofactor in [FeFe]-hydrogenases. Strikingly, two of the Fe/S clusters were rapidly destroyed by molecular oxygen, linking Nar1 oxygen sensitivity in vitro to phenotypes observed previously in vivo. Our biochemical results, therefore, validate a direct link between cellular oxygen concentrations and the functioning of the CIA pathway. These advances also now allow for the pursuit of in vitro Fe/S cluster transfer assays, which will shed light on Fe/S trafficking and insertion by CIA components.
Within the past ten years, genetic evidence has been increasing for the direct role that microbes play in microbiologically influenced corrosion (MIC), also known as biocorrosion or biodeterioration. One prominent example is the correlation between the corrosion of metal and the presence of genes encoding an extracellular [NiFe]-hydrogenase (MIC hydrogenase) in the methanogenic archaeon, Methanococcus maripaludis. In this study, DNA sequencing and bioinformatic analysis were used to classify the MIC hydrogenase as belonging to a core set of genes, the MIC core, found so far in Methanococci and Methanobacteria classes of methanogens. Genetic evidence is provided for the mobilization of the MIC core via multiple mechanisms, including a horizontal gene transfer event from Methanobacteria to Methanococci and a newly described MIC-transposon. A detailed comparison of M. maripaludis genomes further pointed to the relevance that cell wall modifications involving N-glycosylation of S-layer proteins and the MIC hydrogenase likely play in methanogen-induced MIC (Mi-MIC). Microscopic analysis of corrosive methanogens encoding the MIC core indicated that Methanobacterium-affiliated strain IM1 can form extensive biofilms on the surface of corrosion products whereas individual cells of M. maripaludis Mic1c10 were only found localized to crevices in the corrosion layer. An updated model of Mi-MIC involving two modes of action is presented, which predicts that the propensity of cells to adhere to iron surfaces directly influences the rate of corrosion due to the localization of the MIC hydrogenase at the metal-microbe interface.
The recovery of critical metals from spent lithium-ion batteries is a key strategy for sustainable resource management and the circular economy. Conventional hydrometallurgical processes typically rely on strong mineral acids and elevated temperatures, which, although effective, generate hazardous waste and demand high energy inputs. As a greener alternative, deep eutectic solvents (DES) combine low toxicity, non-volatility, simple synthesis, and tunable physicochemical properties,
making them promising media for selective metal recovery1-2. Here, we report for the first time the use of ultrasound (US) to assist the leaching of Li and Co from LiCoO₂ black mass employing a deep eutectic solvent based on choline chloride and formic acid (ChCl:HCOOH, 1:2 molar ratio). The DES was synthesized at 90 °C for 3 h under stirring (300 rpm) and was characterized in terms of its molecular structure and formation by 1H-NMR and FT-IR, as well as by its viscosity and density. For each experiment, ~0.100 g of LiCoO2 was treated with 5 g of DES-FA in an ultrasonic bath (35 kHz, 60 °C) for different irradiation times (30–120 min), followed by three sequential extractions. All measurements were performed by ICP OES. Lithium solubilization reached ~80% at 90 min, while cobalt extraction was stabilizing at ~79% after 120 min. The enhanced performance under US is attributed to sonochemical effects that promote cavitation and microjets, leading to the disruption of particle agglomerates, the thinning of diffusion layers, and the generation of highly reactive local environments. These processes accelerate deintercalation and mass transfer
within the solid–liquid interface. Combined with the mild acidity of DES-FA, which enables simultaneous leaching of both metals while favoring faster kinetics for Li,
ultrasound provided a synergistic effect that enhanced the overall process and preserved the distinct extraction profiles of Li and Co. The extraction behavior of the
two metals can be explained by their different speciation in the DES-FA medium. Cobalt is likely reduced from Co(III) to Co(II) by formic acid and stabilized through the formation of chloro-complexes such as [CoCl4]2- with chloride anions from ChCl, favoring its solubilization. In contrast, lithium does not form stable complexes with chloride under these conditions. It is primarily extracted as a solvated cation, stabilized by the extensive hydrogen-bond network of the DES. This difference accounts for the faster leaching kinetics observed for Li compared to Co. Selective recovery was achieved by pHcontrolled precipitation, with cobalt oxalate at pH 4-5 and lithium carbonate at pH 10. The Eco-Scale score of 85 confirmed the greenness of the method. This pioneering approach highlights the potential of coupling DES chemistry with ultrasound. Together, they represent a sustainable and efficient route
for recovering critical metals from battery waste.