Fachbereich Angewandte Naturwissenschaften
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- Explosives (6)
Explosives trace residues on surfaces are utilized for forensic investigations and to check suspicious objects using technical and non-technical detection procedures. Data about expected trace contaminations after the handling of explosives and how they relate to a potential chemical background help to determine requirements and limitations of detection procedures. Often swab sampling is used for the analysis of surface contaminations. A wet swab sampling procedure was optimized for PETN, TNT and ammonium nitrate. Good results were achieved using PU-foam swabs wetted with a mixture of acetonitrile/water (90/10). The swabs were subsequently solvent extracted and analysed using LC-triple-quad-MS and ion-chromatography. The swabs were applied for the determination of explosives residues in a mock-up car scenario simulating one person loading the car with explosives followed by a short car travel by the same person. As test substances an ANFO, TNT and plasticized PETN were used. Additional samples were taken from indoor installations regularly used for the training of explosive detection dogs as well as other objects and buildings close by. The surface contaminations found in the investigated scenario ranged from the ng to the µg scale. The results indicate that simple cleaning procedures might not sufficient to remove explosives contaminations in training settings for explosives detection dogs. A significant spreading of explosive traces beyond direct contact with the person handling the explosive or with the explosive itself was not observed.
Plant-based bioactive compounds for substitution of petrol-based stabilisers in packaging materials
(2021)
Biopolymers are increasingly used to design drug delivery systems (DDSs), which incorporate therapeutic agents to deliver drugs precisely to the diseased sites with minimal side effects. An ideal DDS targets and controls drug release, protecting drugs from breakdown during transport. Due to their biocompatibility and biodegradability, the DDS made of biopolymers acts as a drug vehicle to reduce the side effects in the body [1].
In this preliminary work, chitosan hydrogels were prepared using 1,3,5-benzene tricarboxylic acid (BTC) as a crosslinker. In addition, the release behavior of the hydrophobic dye (Rhodamine B) from the chitosan hydrogels was examined. The dye was used in this work to visually track and quantify the loading and release behavior.
Ob in Windkraft-, Photovoltaikanlagen oder in der Elektromobilität – überall dort wo hohe Spannungen und Ströme transportiert werden müssen, sind Drahtverbindungen aus hochreinem Aluminium (Al-Gehalt mind. 99,99%) mit Durchmessern zwischen 125 μm und 500 μm unverzichtbar. Jährlich werden über 15 Trillionen Drahtbrücken in elektrischen Modulen verarbeitet. Im Betrieb müssen die Drähte wechselnde mechanische wie auch thermische Belastungen ertragen, die auf Dauer zu einem Ermüden der Drähte und damit zu einem Ausfall des Moduls führen können. Ziel der Promotion ist es daher ein Lebensdauermodell zu entwickeln mit dem die Zuverlässigkeit der Drähte vorhergesagt werden kann.
Illegal wildlife trade is a growing problem internationally. Poaching of animals not only leads to the extinction of populations and species but also has serious consequences for ecosystems and economies. This study introduces a molecular marker system that authorities can use to detect and substantiate wildlife trafficking. SNPSTR markers combine short tandem repeats with single nucleotide polymorphisms within an amplicon to increase discriminatory power. Within the FOGS (Forensic Genetics for Species Protection) project, we have established SNPSTR marker sets for 74 vertebrate species. On average, each set consists of 19 SNPSTR markers with 82 SNPs per set. More than 1300 SNPSTR markers and over 300 STR markers were identified. Also, through its biobanking pipeline, the FOGS project enabled the cryopreservation of somatic cells from 91 vertebrate species as well as viable tissues for later cell initiation from a further 109 species, providing future strategies for ex situ conservation. In addition, many more fixed tissues and DNA samples of endangered species were biobanked. Therefore, FOGS was an interdisciplinary study, combining molecular wildlife forensics and conservation tools. The SNPSTR sets and cell culture information are accessible through the FOGS database (https://fogs-portal.de/data) that is open to scientists, researchers, breeders and authorities worldwide to protect wildlife from illegal trade.
Introduction: Celiac Disease (CD) is a multisystemic auto-mmune disorder triggered by gluten in HLA genetically predisposed individuals. HLA-DQ genotyping is useful to assess the individual susceptibility to CD but still not sufficient for early diagnosis. Here, we propose HLA-DQA1 and HLA-DQB1 gene typing and exosomes characterization as new tool for CD prevention and diagnosis.
Methods: A Chilean population (n=30) was investigated for SNPs mutations in HLA Class II alleles associated with CD predisposition, using the GenoChip Food Technology. Exosomes have been isolated from donors’ serum by ultracentrifugation and characterized by Western Blotting (for CD63 and CD9) and transmission electron microscopy. Exosomes were also studied for their interleukin-1ra content.
Results: Among the studied population, 45.84, 37.46, and 16.70% were carrying alleles encoding for MHC-DQ heterodimers associated with extremely high, high, and extremely low risk to develop CD. The exosome size decreased significantly (p<0.05) when derived from extremely low CD risk donors (44.58 ± 7.88 nm). In parallel, isolated Exosomes from donors with high and extremely high CD risk showed higher IL-1ra content. The values increase within the extremely high-risk group (108.8 ± 15.91 and 148.8 ± 12.37 pg/mL), as the CD persons were not following any treatment. However, these values were lower (52.50 ± 3.54 and 48.75 ± 6.52 pg/mL) in exosomes isolated from CD patients after treatment.
Conclusion: A relationship between exosomes’ size and IL-1ra content, and genetic susceptibility for CD has been observed, suggesting their possible use as biomarkers for CD prevention and diagnosis.
Keywords:
Background. This study was performed to investigate the influence of a short-term treatment with pioglitazone versus placebo on inflammatory activation of mononuclear cells (mRNA expression/protein secretion of inflammatory markers). Methods and Results. Sixty-three patients with well-controlled type 2 diabetes (52 males, 11 females, age (Mean ± SD): 66 ± 7 yrs, disease duration: 6.6 ± 9.6 yrs, HbA1c: 6.7 ± 0.6%) were randomized to additional 45 mg of pioglitazone or placebo to their existing metformin and sulfonylurea therpay for four weeks in a double-blind study design. Protein risk marker levels (hsCRP, MMP-9, MCP-1, etc.) and the expression of NFκB subunits and NFκB-modulated cytokines from isolated peripheral monocyte/macrophages were determined at baseline and endpoint. There were no changes in HbA1c, but significant biomarker improvements were seen with pioglitazone only. The mRNA marker expression was downregulated by pioglitazone and further up-regulated with placebo (e.g., P105 pioglitazone: -19%/placebo: +6%, RelA: -20%/+2%, MMP-9: -36%/+9%, TNFα: -10%/+14%, P < 0.05 between groups in all cases). Conclusions. Pioglitazone very rapidly down-regulated the activated state of peripheral monocytes/macrophages as assessed by mRNA expression of NFκB and NFκB-modulated cytokines and decreased plasma levels of cardiovascular risk marker proteins independent of glycemic control.
AIM
Insulin treatment is considered to be the final option for patients with progressive type 2 diabetes. This study investigated, whether reconverting type 2 patients from insulin treatment to oral treatment using pioglitazone is possible without deterioration of blood glucose control.
METHODS
The PioSwitch study was a prospective, open label, proof of concept study. Thiazolidinedione-naïve patients with residual beta-cell function were switched from an existing insulin therapy to treatment with pioglitazone and glimepiride for 6 months. Efficacy was assessed by laboratory parameters and scores for evaluation of metabolic control, beta-cell function, insulin resistance and cardiovascular risk.
RESULTS
In total, 98 patients [66 men, 32 women, age (mean +/- s.d.): 59 +/- 9 years; disease duration: 5.6 +/- 3.6 years; Hemoglobin A1c (HbA1c): 6.9 +/- 0.8%; body mass index (BMI): 33.9 +/- 5.2 kg/m(2), initial daily insulin therapy dose: 0.36 +/- 0.3 U/kg body weight] out of 117 screened patients were treated. During the observation period, 23 patients were prematurely terminated because of an increase in HbA1c from baseline > 0.5% or other reasons. In 75 patients (76%), no deterioration of glucose metabolism occurred and additional improvements were seen in the majority of the observation parameters [baseline vs. endpoint; HbA1c: 6.79 +/- 0.74%/6.66 +/- 0.69% (p < 0.05), glucose: 6.4 +/- 1.5/5.2 +/- 1.4 mmol/l (p < 0.001), adiponectin: 7 +/- 3 mg/l/17 +/- 8 mg/l (p < 0.001), C-peptide: 987 +/- 493/1756 +/- 789 (p < 0.001), sensitivity index derived from the intravenous glucose tolerance test (SI(ivGTT)): 1.21 +/- 0.85/1.49 +/- 0.95 (p < 0.05), hsCRP: 3.3 +/- 2.4/2.6 +/- 2.4 mg/l (p < 0.01), macrophage chemo-attractant protein 1 (MCP1): 487 +/- 246/382 +/- 295 ng/l (p < 0.05)]. BMI increased from 33.8 +/- 5.1 to 34.4 +/- 5.3 kg/m(2) (p < 0.001).
CONCLUSIONS
The switch from insulin therapy resulting in a moderately HbA1c level, to oral treatment with pioglitazone was successful in a majority of patients with sufficient residual beta-cell function. It allows a simple and less expensive therapy with a better cardiovascular risk marker profile.
Die Nachfrage nach nachhaltigen, umweltfreundlichen und CO2-reduzierten Dämmstoffen steigt stetig. Insbesondere im Hinblick auf den fortschreitenden Klimawandel, sind die Reduzierung des CO2-Ausstoßes, die Verringerung des Energieverbrauchs von Gebäuden, sowie die Schonung natürlicher Ressourcen, wichtige Forderungen für den Erhalt der Umwelt. Zu den am häufigsten eingesetzten Wärmedämmstoffen zählen derzeit Polystyren, Polyurethan und Mineralwolle, für deren Herstellung jedoch eine erhebliche Menge an Energie eingesetzt werden muss. Eine sinnvolle Alternative stellen Dämmstoffe auf Basis nachwachsender Rohstoffe dar. Als sehr aussichtsreiche Gruppe von nachwachsenden Rohstoffen gelten mehrjährige, schnellwachsende Low-input Kulturen, wie das aus dem ostasiatischen Raum stammende Großgras Miscanthus. Ziel dieser Arbeit liegt in der Entwicklung und Charakterisierung Miscanthus faserverstärkter Geopolymerschäume für den Einsatz als Dämmstoff. Dazu wurden zunächst die Grundlagen aus Bereichen nachwachsender Rohstoffe, Dämmstoffe, Schaumtechnologie sowie Geopolymeren zusammengetragen. Ein besonderer Schwerpunkt lag dabei auf der Herstellung von naturfaserverstärkten Geopolymerschäumen. Ausgehend von den Grundlagen wurde der Ausgangsstoff Miscanthus hinsichtlich seiner Dämmeigenschaften, wie Wärmeleitfähigkeit und Porenstruktur charakterisiert und im Anschluss durch Kombination mit geschäumten Geopolymeren, Miscanthus faserverstärkte Dämmstoffplatten hergestellt. Mittels statistischer Versuchsplanung wurde im nächsten Schritt der Einfluss verschiedener Faktoren (Fasergehalt, Faserlänge, Aushärtungstemperatur, Menge an Schaumbildner, Gehalt an pyrogener Kieselsäure und spezifische Oberfläche der pyrogenen Kieselsäure) auf die Wärmeleitfähigkeit und Druckfestigkeit der hergestellten Dämmstoffe untersucht. Im Ergebnis konnte dabei ein signifikanter Einfluss des Fasergehalts, der Faserlänge und der Menge an Schaumbildner festgestellt werden. Untersuchungen zur Porosität, mineralogischen Zusammensetzung, Molekülstruktur, sowie Mikrostruktur ergänzen diese Ergebnisse. Abschließend wurde auf Grundlage der statistischen Daten eine optimale Zusammensetzung mit niedriger Wärmeleitfähigkeit und gleichzeitig hoher Druckfestigkeit ermittelt.
The demand for sustainable, environmentally friendly, and low-carbon insulation materials is constantly increasing. Especially considering the progression of climate change, reducing CO2 emissions, reducing the energy consumption of buildings, and conserving natural resources are all important requirements for preserving the environment. The most frequently used thermal insulation materials currently include polystyrene, polyurethane, and mineral wool, but a considerable amount of energy is used in their production. Insulation materials based on renewable raw materials are a sensible alternative. An extremely promising group of renewable raw materials includes multi-year, fast-growing low-input crops, such as the tall grass Miscanthus from East Asia. The aim of this paper is the development and characterization of Miscanthus fiber-reinforced geopolymer foams for use as insulation material. To this end, the basics of renewable raw materials, insulation materials, foam technology and geopolymers were compiled first. Particular attention was paid to the production of natural fiber stabilized geopolymer foams. Starting from the basics, the raw material Miscanthus was characterized with regard to its insulating properties such as thermal conductivity and pore structure, and subsequently Miscanthus fiber-reinforced insulation boards were produced by combining with foamed geopolymers. In the next step, the influence of various factors (fiber content, fiber size, curing temperature, foaming agent content, content of fumed silica and specific surface area of the fumed silica) on the thermal conductivity and compressive strength of the produced insulating materials was investigated by means of statistical experiment planning. As a result, it could be determined that the fiber content, fiber size and foaming agent content had a significant influence. Investigations concerning porosity, mineralogical composition, molecular structure, and microstructure complement these results. Finally, an optimal composition with low thermal conductivity, and at the same time high compressive strength, was determined based on the statistical data.
Pollution with anthropogenic waste, particularly persistent plastic, has now reached every remote corner of the world. The French Atlantic coast, given its extensive coastline, is particularly affected. To gain an overview of current plastic pollution, this study examined a stretch of 250 km along the Silver Coast of France. Sampling was conducted at a total of 14 beach sections, each with five sampling sites in a transect. At each collection site, a square of 0.25 m2 was marked. The top 5 cm of beach sediment was collected and sieved on-site using an analysis sieve (mesh size 1 mm), resulting in a total of approximately 0.8 m3 of sediment, corresponding to a total weight of 1300 kg of examined beach sediment. A total of 1972 plastic particles were extracted and analysed using infrared spectroscopy, corresponding to 1.5 particles kg−1 of beach sediment. Pellets (885 particles), polyethylene as the polymer type (1349 particles), and particles in the size range of microplastics (943 particles) were most frequently found. The significant pollution by pellets suggests that the spread of plastic waste is not primarily attributable to tourism (in February/March 2023). The substantial accumulation of meso- and macro-waste (with 863 and 166 particles) also indicates that research focusing on microplastics should be expanded to include these size categories, as microplastics can develop from them over time.
Due to the toxicity and negative environmental impact of lead- and chromate(IV and VI)-based delay compositions, alternative substance mixtures are required to be investigated as possible substitutes for pyrotechnic materials. Therefore, the Mg/ CaO2 and Mg/Li2O2 delay compositions were subject of this work. These mixtures were processed into pellets with the aid of the dry binders HPMC, MgSt, PEG1, PEG2 and PVP and used in delay elements. The binder content used for all the composition was 5 wt%. Burning rates were investigated while taking the influence of oxidizer particle size and the effect of different binders into account. The results show that the combustion rate can be adjusted both via the grain size and by means of the various binders. Further, the impact of the different binders on the ignition temperature of the Mg/Li2O2 and Mg/CaO2 compositions was measured. The compositions were also classified as insensitive to impact and friction. However, during preparation of delay pallets, unintended ignition of pellets occurred while using the HPMC, PEG1, PEG2 and PVP binders. For this reason, safety measures should be followed and special care should be taken while preparing delay pellets. While the peroxides could be identified with Raman spectroscopy, no peroxide residue was found in the reaction products of both peroxide magnesia mixtures.
Triacetone triperoxide (TATP) and Hexamethylene triperoxide diamine (HMTD), known for their propensity towards use in improvised explosive devices due to facile synthesis from readily accessible precursors, present a considerable security challenge. Their sensitivity to mechanical stimuli, such as impact and friction, as well as to thermal input, necessitates the development of advanced detection methodologies. This study is dedicated to evaluate the influence of varied laser beam parameters during radiation on these peroxide-based energetic materials. A novel approach for the controlled energy delivery to substances under investigation involves the application of coatings with predefined absorption coefficients. This technique, coupled with the careful selection of laser parameters, enables the controlled local initiation of reaction in the energetic material without reaching the threshold for mass combustion, thereby avoiding detonation or deflagration. The experimental setup involves the laser irradiation of defined quantities of graphite-coated TATP and HMTD, with the subsequent laser processing being monitored using a sensitive microphone. This set-up enables a detailed investigation of the physical phenomena that manifest themselves during the interaction and thus contributes to the state of knowledge about the safe handling and detection of these energetic materials.
Aberrant Ras homologous (Rho) GTPase signalling is a major driver of cancer metastasis, and GTPase-activating proteins (GAPs), the negative regulators of RhoGTPases, are considered promising targets for suppressing metastasis, yet drug discovery efforts have remained elusive. Here, we report the identification and characterization of adhibin, a synthetic allosteric inhibitor of RhoGAP class-IX myosins that abrogates ATPase and motor function, suppressing RhoGTPase-mediated modes of cancer cell metastasis. In human and murine adenocarcinoma and melanoma cell models, including three-dimensional spheroid cultures, we reveal anti-migratory and anti-adhesive properties of adhibin that originate from local disturbances in RhoA/ROCK-regulated signalling, affecting actin-dynamics and actomyosin-based cell-contractility. Adhibin blocks membrane protrusion formation, disturbs remodelling of cell-matrix adhesions, affects contractile ring formation, and disrupts epithelial junction stability; processes severely impairing single/collective cell migration and cytokinesis. Combined with the non-toxic, non-pathological signatures of adhibin validated in organoids, mouse and Drosophila models, this mechanism of action provides the basis for developing anti-metastatic cancer therapies.
Background: The global rate of Caesarean section (CS) is 21.1 % (2021) and is rising worldwide. CS presents the third highest cumulative incidence for surgical site infections. Maternal infections around the time of childbirth account for 1 out of 10 maternal deaths worldwide. Therefore, perioperative antibiotic prophylaxis (PAP) during CS is common standard of care and part of numerous recommendations from expert bodies such as the World Health Organization (WHO) and different national gynecological professional associations. According to these, first and second generation cephalosporins like cefuroxime are the agents of choice for this indication. In fact, the use of PAP significantly reduces maternal morbidity and mortality rates. Whereas the side effect of this measure on the microbiome of the newborn has been the subject of repeated clinical studies, data on specific and especially long-term effects on the gut microbiome of the mothers are still lacking. MAMA is the first study to specifically and systematically investigate this question.
The epithelial sodium channel (ENaC) plays a key role in osmoregulation in tetrapod vertebrates and is a candidate receptor for salt taste sensation. There are four ENaC subunits (alpha, beta, gamma, & delta) which form alpha beta gamma or delta beta gamma-ENaCs. While alpha beta gamma-ENaC is a maintenance protein controlling sodium and potassium homeostasis, delta beta gamma-ENaC might represent a stress protein monitoring high sodium concentrations. The delta-subunit emerged with water-to-land transition of tetrapod vertebrate ancestors. We investigated the evolutionary path of ENaC-coding genes in Cetartiodactyla, a group comprising even-toed ungulates and the cetaceans (whales/dolphins) which transitioned from terrestrial to marine environments in the Eocene. The genes SCNN1A (alpha-ENaC), SCNN1B (beta-ENaC) and SCNN1G (gamma-ENaC) are intact in all 22 investigated cetartiodactylan families. While SCNN1D (delta-ENaC) is intact in terrestrial Artiodactyla, it is a pseudogene in 12 cetacean families. A fusion of SCNN1D exons 11 and 12 under preservation of the open reading frame was observed in the Antilopinae, representing a new feature of this clade. Transcripts of SCNN1A, SCNN1B and SCNN1G were present in kidney and lung tissues of Bottlenose dolphins, highlighting alpha beta gamma-ENaC's role as a maintenance protein. Consistent with SCNN1D loss, Bottlenose dolphins and Beluga whales did not show behavioural differences to stimuli with or without sodium in seawater-equivalent concentrations. These data suggest a function of delta-ENaC as a sodium sensing protein which might have become obsolete in cetaceans after the migration to high-salinity marine environments. Consistently, there is reduced selection pressure or pseudogenisation of SCNN1D in other marine mammals, including sirenians, pinnipeds and sea otter.
The lysosomal cation channel TMEM175 is crucial for maintaining lysosomal function and pH homeostasis, and its aberrant function is linked to Parkinson’s disease (PD). While TMEM175 activity was first interpreted in the context of its potassium (K+) selective conductance, subsequent studies revealed also a substantial permeability to protons (H+). Here we dissect the complex changes in TMEM175 conductance and current reversal voltages in response to pH jumps on the luminal side of the channel protein. In whole-cell patch clamp experiments with plasma membrane redistributed TMEM175 we show that a pH jump from symmetrical pH 7.4 to pH 4.7 on the luminal side triggers a continuous rise in inward and outward current, concomitant with a transient positive excursion of the reversal voltage (Erev). The peak Erev shift remains almost 100 mV below the estimated equilibrium voltage for protons and shows little sensitivity to the K+ gradient. The data are consistent with a scenario in which a TMEM175 mediated proton flux elicits a fast collapse of the pH gradient. In MD simulations we identify the luminal H57 as titratable partner for the formation of intra- and inter-subunit salt bridges with D279 and E282 for stabilizing the channel open state. This presumed gating function is confirmed by mutational studies and lysosomal patch-clamp experiments in which a H57Y mutant exhibits a reduced pH dependency of activation. Our findings contribute to a better comprehension of TMEM175’s complex electrophysiological properties and foster understanding of TMEM175 as a pharmacological target for neurodegenerative disease therapy.
Effects of Stretch-Bending Straightening on the Tensile Properties of Cold Rolled Packaging Steel
(2024)
Achieving perfect flatness, tension-free surfaces, and exceptional resistance to spring back are important characteristics of packaging steel, setting the standard for high-quality material performance. To guarantee these crucial parameters, the implementation of the stretch-bending process at the final stage of the production route is indispensable. Besides improving the flatness properties, the induced plastic deformation results in an accompanying change in the mechanical properties. This investigation focuses on understanding this change in mechanical properties due to different stretch-bending straightening process parameters. A multivariate predictive model is created to calculate a process window for achieving the desired flatness and also mechanical properties in the production of packaging steel. This model is validated by experiments with a laboratory facility.
Modern forensic DNA quantitation assays provide information on the suitability of a DNA extract for a particular type of analysis, on the amount of sample to put into the analysis in order to yield an optimal (or best possible) result, and on the requirement for optional steps to improve the analysis. To achieve a high sensitivity and specificity, these assays are based on quantitative PCR (qPCR) and analyze target DNA loci that are present in multiple copies distributed across the genome. These target loci allow the determination of the amount of DNA, the degree of DNA degradation, and the proportion of DNA from male contributors. In addition, internal control DNA of a known amount is analyzed in order to inform about the presence of PCR inhibitors. These assays are nowadays provided as commercial kits that have been technically validated and are compatible with common qPCR instruments. In this review, the principles of forensic qPCR assays will be explained, followed by information on the nature of DNA loci targeted by modern forensic qPCR assays. Finally, we critically draw attention to the current trend of manufacturers not to disclose the exact nature of the target loci of their commercial kits.
Design and characterization of geopolymer foams reinforced with Miscanthus x giganteus fibres
(2024)
This paper presents the results of the optimisation and characterization of Miscanthus fibre reinforced geopolymer foams based on fly ash and represents an important step forward in the development of a sustainable and environmentally friendly insulation material. Miscanthus belongs to a promising group of renewable raw materials with favourable thermal insulation properties. Design of experiment (DoE) were used to optimize the thermal conductivity and compressive strength of Miscanthus x giganteus reinforced geopolymer foams. In addition, the samples was analyzed using X-ray diffraction (XRD), Field emission scanning electron microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FTIR). Mixtures with a low thermal conductivity of 0.056 W (m K)−1 and a porosity of 79 vol% achieved a compressive strength of only 0.02 MPa. In comparison, mixtures with a thermal conductivity of 0.087 W (m K)−1 and a porosity of 58 vol% achieved a compressive strength of 0.45 MPa. Based on the determined parameters especially due to the low compressive strength, an application as cavity insulation or insulation between rafters is possible.
The goal of this study was to explore a route for introducing functionalities into agarose-based hydrogels to tune the physical, chemical, and biological properties. Several agarose derivatives were prepared by homogeneous synthesis, including anionic agarose sulfates (ASs), reactive azido agaroses (AZAs), and cationic agarose carbamates (ACs), as well as agarose tosylates (ATOSs) and agarose phenyl carbonates (APhCs). The products were characterized in terms of their molecular structure and solubility behavior. The results suggest that the native gel-forming ability of agarose is retained if the introduced functionalities are hydrophilic, and the overall degree of substitution is low (DS < 0.5). Thus, functional hydrogels from several agarose derivatives could be obtained. The mechanical stability of the functional hydrogels was decreased compared to native agarose gels but was still in a range that enables safe handling. An increase in mechanical strength could be achieved by blending functional agarose derivatives and agarose into composite hydrogels. Finally, it was demonstrated that the novel functional agarose hydrogels are biocompatible and can potentially stimulate interactions with cells and tissue.
The autocatalyzed ethanolic organosolv process is gaining increasing attention for the sulfur-free isolation of lignin, which is subsequently used as a renewable substitute for various fossil-based applications. For the first time, the mechanochemical influence of seven different particle sizes of two different biomasses on the respective organosolv lignin structure is examined. Wine pruning (Pinot Noir) and wine pomace (Accent) are used for organosolv process with particle sizes ranging from 2.0–1.6 mm to less than 0.25 mm. As particle size decreases, the weight-average molecular weight increases, while the total phenol content decreases significantly. Additionally, the distribution of the lignin-typical monolignols and relevant substructures, as determined by two-dimensional heteronuclear nuclear magnetic resonance spectra single quantum coherence (HSQC), is observed. The degree of grinding of the biomass has a clear chemical–structural influence on the isolated HG and HGS organosolv lignins. Therefore, it is crucial to understand this influence to apply organosolv lignins in a targeted manner. In the future, particle size specifications in the context of the organosolv process should be expressed in terms of distribution densities rather than in terms of a smaller than specification.
The treatment of ultrapure water with electrochemically produced O3 is a common means for disinfection yet leads to the formation of a variety of reactive oxygen species (ROS). The present study draws a comprehensive comparison between three commonly used photometric and fluorometric assays for ROS analysis and quantifies the individual signal responses for dissolved O3, ·OH and H2O2, respectively, to account for cross-sensitivities. By calibrating all combinations of assays and analytes, we developed a quantification procedure to reliably determine the actual ROS composition in ultrapure water environments for different operation conditions of a membrane water electrolyzer with PbO2 anodes down to concentrations of 0.97 μg L−1. While the ·OH formation rate can be described linearly over the observed current density range, substantial O3 evolution is only found for current densities of 0.75 A cm−2 and above (up to 3.7 μmol h−1 for J = 1.25 A cm−2). The formation of H2O2 is only observed when an organic carbon source is introduced into the solution. We further quantify the interference of H2O2 with the reading of the oxidation-reduction potential as a common water parameter and elaborate on its validity to monitor the peroxone process when both H2O2 and O3 are present simultaneously.
To respond to the increasing demand for hyaluronic acid (HA) in dietary supplements (DSs) and nutricosmetics marketed for the treatment of osteoarthritis or moistening, it is essential to have an accurate and reliable method for its analysis in the final products. The study aimed to develop and validate alternative method for the quality control of HA in DSs using low-field (LF) and high-field (HF) nuclear magnetic resonance (NMR) spectroscopy at 80 MHz and 600 MHz, respectively. Moreover, chondroitin sulphate (CH), another active ingredient in DSs, can be simultaneously quantified. The 1H-NMR methods have been successfully validated in terms of limit of detection (LOD) and limit of quantitation (LOQ), which were found to be 0.1 mg/mL and 0.2 mg/mL (80 MHz) as well as 0.2 mg/mL and 0.6 mg/mL (600 MHz). Recovery rates were estimated to be between 92 and 120% on both spectrometers; precision including sample preparation was found to be 4.2% and 8.0% for 600 MHz and 80 MHz, respectively. Quantitative results obtained by HF and LF NMR were comparable for 16 DSs with varying matrix. HF NMR experiments at 70 ℃ serve as a simple and efficient quality control tool for HA and CH in multicomponent DSs. Benchtop NMR measurements, upon preceding acid hydrolysis, offer a cost-effective and cryogen-free alternative for analyzing DSs in the absence of CH and paramagnetic matrix components.
Tauopathies are a heterogeneous group of neurologic diseases characterized by pathological axodendritic distribution, ectopic expression, and/or phosphorylation and aggregation of the microtubule-associated protein TAU, encoded by the gene MAPT. Neuronal dysfunction, dementia, and neurodegeneration are common features of these often detrimental diseases. A neurodegenerative disease is considered a primary tauopathy when MAPT mutations/haplotypes are its primary cause and/or TAU is the main pathological feature. In case TAU pathology is observed but superimposed by another pathological hallmark, the condition is classified as a secondary tauopathy. In some tauopathies (e.g. MAPT-associated frontotemporal dementia (FTD), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and Alzheimer's disease (AD)) TAU is recognized as a significant pathogenic driver of the disease. In many secondary tauopathies, including Parkinson's disease (PD) and Huntington's disease (HD), TAU is suggested to contribute to the development of dementia, but in others (e.g. Niemann-Pick disease (NPC)) TAU may only be a bystander. The genetic and pathological mechanisms underlying TAU pathology are often not fully understood. In this review, the genetic predispositions and variants associated with both primary and secondary tauopathies are examined in detail, assessing evidence for the role of TAU in these conditions. We highlight less common genetic forms of tauopathies to increase awareness for these disorders and the involvement of TAU in their pathology. This approach not only contributes to a deeper understanding of these conditions but may also lay the groundwork for potential TAU-based therapeutic interventions for various tauopathies.
Bone is a metabolically dynamic structure that is generally remodeled throughout the lifetime of an individual but often causes problems with increasing age. A key player for bone development and homeostasis, but also under pathological conditions, is the bone vasculature. This complex system of arteries, veins, and capillaries forms distinct structures where each subset of endothelial cells has important functions. Starting with the basic process of angiogenesis and bonespecific blood vessel formation, coupled with initial bone formation, the importance of different vascular structures is highlighted with respect to how these structures are maintained or changed during homeostasis, aging, and pathological conditions. After exemplifying the current knowledge on bone vasculature, this review will move on to exosomes, a novel hotspot of scientific research. Exosomes will be introduced starting from their discovery via current isolation procedures and state-of-the-art characterization to their role in bone vascular development, homeostasis, and bone regeneration and repair while summarizing the underlying signal transduction pathways. With respect to their role in these processes, especially mesenchymal stem cell-derived extracellular vesicles are of interest, which leads to a discussion on patented applications and an update on ongoing clinical trials. Taken together, this review provides an overview of bone vasculature and bone regeneration, with a major focus on how exosomes influence this intricate system, as they might be useful for therapeutic purposes in the near future.
A titrant for the SARS-CoV-2 main protease (Mpro) was developed that enables, for the first time, the exact determination of the concentration of the enzymatically active Mpro by active-site titration. The covalent binding mode of the tetrapeptidic titrant was elucidated by the determination of the crystal structure of the enzyme–titrant complex. Four fluorogenic substrates of Mpro, including a prototypical, internally quenched Dabcyl-EDANS peptide, were compared in terms of solubility under typical assay conditions. By exploiting the new titrant, key kinetic parameters for the Mpro-catalyzed cleavage of these substrates were determined.
In der vorliegenden Arbeit werden die nematischen Flüssigkristallgemische (E7 und E8) zum Zwecke der Gassensorik mit einer reaktiven, optisch aktiven Substanz dotiert. Die Dotierung verursacht die Ausbildung einer chiral-nematischen Phase, die einen eindimensionalen photonischen Kristall mit Reflexionsmaxima im sichtbaren Bereich des elektromagnetischen Spektrums erzeugt. Infolge einer chemischen Reaktion des Dotiermittels mit dem einem Analyten, ändert sich mit seiner chemischen Zusammensetzung auch dessen helical twisting power (HTP). Diese Änderung verursacht eine Verschiebung des reflektierten Wellenlängenbereichs, was als Änderung der farblichen Erscheinung mit dem bloßen Auge wahrgenommen werden kann. In dieser Arbeit wird das koaxiale Elektrospinnen verwendet, um Flüssigkristalle in Polymerfasern von wenigen Mikrometern Durchmesser einzukapseln. Der Vergleich zwischen eingekapseltem und nicht eingekapseltem dotierten Flüssigkristall wird mit einer dafür entwickelten Reaktionskammer UV/VIS-spektroskopisch durchgeführt. Die ablaufenden Reaktionen werden mittels FTIR-Spektroskopie untersucht. Die Fasern und die verwendeten Flüssigkristalle werden lichtmikroskopisch charakterisiert. Es werden zusätzlich Möglichkeiten untersucht die Wasserbeständigkeit der hergestellten Fasern zu verbessern, um ihre Eignung für künftige technische Anwendungen zu steigern. Hierzu wird das triaxiale Elektrospinnen verwendet, um die Fasern mit einer zusätzlichen wasserbeständigen Polymerhülle zu überziehen. Es wird zudem die Möglichkeit untersucht koaxial gesponnene Fasern nachträglich zu vernetzen, um so eine Wasserfestigkeit zu erzielen.
Explosives detection dog (EDD) teams are deployed at mass events such as concerts, annual general meetings of large listed companies or in air cargo security. However, outside of EU-regulated air cargo, there is no common quality standard for commercial EDD in Germany and many neighboring countries. While law enforcement agencies have access to experienced chemists and can conduct dog training with homemade explosives, small commercial security services do not have comparable capabilities and face additional legal hurdles. The DIN SPEC 77201 was developed within the project to fulfil the need for a generally accepted quality standard. A training workshop was developed and transferred from the academic sector to commercial partners in order to improve training opportunities with home-made explosives, providing new insights for training EDD teams with TATP, HMTD or training aids.
Sulfite intoxication is the hallmark of four ultrarare disorders that are caused by impaired sulfite oxidase activity due to genetic defects in the synthesis of the molybdenum cofactor or of the apoenzyme sulfite oxidase. Delays on the diagnosis of these disorders are common and have been caused by their unspecific presentation of acute neonatal encephalopathy with high early mortality, followed by the evolution of dystonic cerebral palsy and also by the lack of easily available and reliable diagnostic tests. There is significant variation in survival and in the quality of symptomatic management of affected children. One of the four disorders, molybdenum cofactor deficiency type A (MoCD-A) has recently become amenable to causal treatment with synthetic cPMP (fosdenopterin). The evidence base for the rational use of cPMP is very limited. This prompted the formulation of these clinical guidelines to facilitate diagnosis and support the management of patients. The guidelines were developed by experts in diagnosis and treatment of sulfite intoxication disorders. It reflects expert consensus opinion and evidence from a systematic literature search.
This study explores the tuning of a Pd/Al2O3 hydrogenation catalyst for the selective removal of trace acetylene from ethylene-rich feeds by coating the catalyst with non-functionalized and functionalized ionic liquids (denoted as SCILL and Advanced SCILL materials, respectively). These materials were tested in an automated continuous hydrogenation rig converting 3300 ppm of acetylene in excess ethylene, a gas mixture mimicking a technical front-end steam cracker feed composition. While the sulfonic-acid-functionalized IL coating resulted in a highly active but very unselective catalyst converting mainly ethylene to ethane, an Advanced SCILL catalyst prepared from a nitrile-functionalized IL reduced the acetylene concentration down to less than 1 ppm, while leaving over 99% of the ethylene untouched. We also examined the potential transformations of the IL layer under reaction conditions by means of 1H NMR. Except for a ketone-functionalized IL, which was inherently labile, all tested ILs primarily underwent C2-ethylation or remained unaltered. Our findings highlight the great potential of functionalized ILs in modifying heterogeneous hydrogenation catalysts.
Sensoren können verschiedene Aufgaben erfüllen, wie beispielsweise die Optimierung von Prozessen, die Interaktion zwischen Geräten oder die Verbesserung der zivilen Sicherheit. [1–3] Ihr Bedarf für die Industrie oder den Alltag wächst seit Jahren stetig. Besonders mobile Gassensoren sind von großem Interesse. Jedoch ist ihre Anwendung meist durch ihre integrierte Batterie begrenzt. Gassensoren ohne oder mit einem nur sehr geringen Energieverbrauch stehen daher im Interesse bei neuen Anwendungsgebieten, beispielsweise im Brandschutz oder in der Textilindustrie. [4,5] Die Sensoren könnten zum Beispiel in die Textilien einer persönlichen Schutzausrüstung eingearbeitet werden und durch einen Farbumschlag die Anwesenheit eines Gases oder die Überschreitung des Grenzwertes toxischer Substanzen anzeigen.
Pollution with anthropogenic waste, particularly persistent plastic, has now reached every remote corner of the world. The French Atlantic coast, given its extensive coastline, is particularly affected. To gain an overview of current plastic pollution, this study examined a stretch of 250 km along the Silver Coast of France. Sampling was conducted at a total of 14 beach sections, each with five sampling sites in a transect. At each collection site, a square of 0.25 m2 was marked. The top 5 cm of beach sediment was collected and sieved on-site using an analysis sieve (mesh size 1 mm), resulting in a total of approximately 0.8 m3 of sediment, corresponding to a total weight of 1300 kg of examined beach sediment. A total of 1972 plastic particles were extracted and analysed using infrared spectroscopy, corresponding to 1.5 particles kg−1 of beach sediment. Pellets (885 particles), polyethylene as the polymer type (1349 particles), and particles in the size range of microplastics (943 particles) were most frequently found. The significant pollution by pellets suggests that the spread of plastic waste is not primarily attributable to tourism (in February/March 2023). The substantial accumulation of meso- and macro-waste (with 863 and 166 particles) also indicates that research focusing on microplastics should be expanded to include these size categories, as microplastics can develop from them over time.
In this work, the surface reactions of the homemade explosive triacetone triperoxide on tungsten oxide (WO3) sensor surfaces are studied to obtain detailed information about the chemical reactions taking place. Semiconductor gas sensors based on WO3 nanopowders are therefore produced and characterized by scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. To analyze the reaction mechanisms at the sensor surface, the sensor is monitored online under operation conditions using Raman spectroscopy, which allows to identify the temperature-dependent sensor reactions. By combining information from the Raman spectra with data on the changing resistivity of the underlying semiconductor, it is possible to establish a correlation between the adsorbed gas species and the physical properties of the WO3 layer. In the results, it is indicated that a Lewis acid–base reaction is the most likely mechanism for the increase in resistance observed at temperatures below 150 °C. In the results, at higher temperatures, the assumption of a radical mechanism that causes a decrease in resistance is supported.
DT-13 attenuates inflammation by inhibiting NLRP3-inflammasome related genes in RAW264.7 macrophages
(2024)
Plant derived saponins or other glycosides are widely used for their anti-inflammatory, antioxidant, and anti-viral properties in therapeutic medicine. In this study, we focus on understanding the function of the less known steroidal saponin from the roots of Liriope muscari L. H. Bailey – saponin C (also known as DT-13) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages in comparison to the well-known saponin ginsenoside Rk1 and anti-inflammatory drug dexamethasone. We proved that DT-13 reduces LPS-induced inflammation by inhibiting nitric oxide (NO) production, interleukin-6 (IL-6) release, cycloxygenase-2 (COX-2), tumour necrosis factor-alpha (TNF-α) gene expression, and nuclear factor kappa-B (NFκB) translocation into the nucleus. It also inhibits the inflammasome component NOD-like receptor family pyrin domain containing protein 3 (NLRP3) regulating the inflammasome activation. This was supported by the significant inhibition of caspase-1 and interleukin-1 beta (IL-1β) expression and release. This study demonstrates the anti-inflammatory effect of saponins on LPS-stimulated macrophages. For the first time, an in vitro study shows the attenuating effect of DT-13 on NLRP3-inflammasome activation. In comparison to the existing anti-inflammatory drug, dexamethasone, and triterpenoid saponin Rk1, DT-13 more efficiently inhibits inflammation in the applied cell culture model. Therefore, DT-13 may serve as a lead compound for the development of new more effective anti-inflammatory drugs with minimised side effects.