Ingenieurwissenschaften und zugeordnete Tätigkeiten
Filtern
Dokumenttyp
- Vortrag (25)
- Zeitschriftenartikel (14)
- Posterpräsentation (11)
- Beitrag zu einem Tagungsband (5)
- Sonstiges (3)
- Forschungsbericht (2)
- Buchkapitel (1)
Schlagworte
- Nano (15)
- OECD (11)
- Nanomaterial (7)
- Prüfrichtlinie (6)
- Reference material (4)
- Affinity chromatography (3)
- Antibodies (3)
- Architecture (3)
- Chemical durability (3)
- Construction products (3)
Organisationseinheit der BAM
- 4.2 Material-Mikrobiom Wechselwirkungen (61) (entfernen)
Eingeladener Vortrag
- nein (25)
AbstractThe correlation between altered extracellular pH and various pathological conditions, including cancer, inflammation and metabolic disorders, is well known. Bulk pH measurements cannot report the extracellular pH value at the cell surface. However, there is a limited number of suitable tools for measuring the extracellular pH of cells with high spatial resolution, and none of them are commonly used in laboratories around the world. In this study, a versatile ratiometric nanosensor for the measurement of extracellular pH was developed. The nanosensor consists of biocompatible polystyrene nanoparticles loaded with the pH-inert reference dye Nile red and is surface functionalized with a pH-responsive fluorescein dye. Equipped with a targeting moiety, the nanosensor can adhere to cell membranes, allowing direct measurement of extracellular pH at the cell surface. The nanosensor exhibits a sensitive ratiometric pH response within the range of 5.5–9.0, with a calculated pKa of 7.47. This range optimally covers the extracellular pH (pHe) of most healthy cells and cells in which the pHe is abnormal, such as cancer cells. In combination with the nanosensors ability to target cell membranes, its high robustness, reversibility and its biocompatibility, the pHe nanosensor proves to be well suited for in-situ measurement of extracellular pH, even over extended time periods. This pH nanosensor has the potential to advance biomedical research by improving our understanding of cellular microenvironments, where extracellular pH plays an important role.
Reliable measurement of the size of polydisperse, complex-shaped commercial nanopowders is a difficult but necessary task, e.g., for regulatory requirements and toxicity risk assessment. Suitable methods exist for the accurate characterization of the size of non-aggregated, stabilized, spherical and monodisperse nanoparticles. In contrast, industrial nanoscale powders usually require dedicated sample preparation procedures developed for the analysis method of choice. These nano-powders tend to agglomerate and/or aggregate, a behavior which in combination with an innate broad particle size distribution and irregular shape often significantly alters the achievable accuracy of the measured size parameters. The present study systematically tests two commercially available nanoscale powders using different sample preparation methods for correlative analysis by scanning electron microscopy, dynamic light scattering, Brunauer–Emmet–Teller method and differential mobility analysis. One focus was set on the sample preparation by embedding nanoparticles in carbon-based hot-mounting resin. Literature on this topic is scarce and the accuracy of the data extracted from cross sections of these particles is unclearly stated. In this paper systematic simulations on the deviation of the size parameters of well-defined series of nanoparticles with different shapes from the nominal value were carried out and the contributing factors are discussed.
Regional standardisation activities and how VAMAS can help in any way to promote activities are reported.
Activities related to organisational updates, government initiatives/priorities (especially related to Materials), details of any strategy documents publicly available, networks within Germany and how we engage are presented.
Die Bestimmung der Nanopartikelgrößen- und -formverteilung nach OECD TG 125 mit einem Differentiellen Mobilitäts Analyse System (DMAS), auch bekannt als SMPS, wird vorgestellt:
- Generelles Messprinzip
- Welchen Durchmesser misst die Methode?
- Welche Partikel kann diese Methode messen?
- Welche Informationen kann diese Methode liefern?
- Wo stößt die Methode an ihre Grenzen?
- Implementierung und Datenauswertung,
- Reporting.
Anschließend wurde eine Q&A-Session für DMAS/SMPS organisiert.
OECD Prüfrichtlinie 125
(2023)
Diese Präsentation ist eine Einführung in die OECD TG 125 zur Bestimmung der Partikelgrößen von Nanomaterialien. Es wird auf die verchiedenen Probleme der Partikelgrößenbestimmung eingegangen wie z.B. verschiedene Oberflächenschichten, Äquivalenzdurchmesser und Verteilungsfunktionen. Gleichzeitig werden die neuen Begrifflichkeiten eingeführt, die in der TG 125 definiert neu werden.
The presentation gives general information about the European Standard EN 16516 “Construction products – Assessment of release of dangerous substances – Determination of emissions into indoor air”. This test standard was developed based on the mandate M/366 of the European commission and is a horizontal reference method for the determination of volatile organic compounds (VOC) from different classes of construction (building) products. Specific test conditions are to be selected by the product TCs (technical committees) in a way that a product is tested under its intended condition of use.
The test is based on the use of emission test chambers which are operated at constant air change rate and climate (23°C, 50 % r.h.) over 28 days. The standard defines the conditions and requirements for the measurement including loading factor, air change rate, sampling, analysis and calculation of emission rates of the substances. A 30 m³ reference room is described which is used to calculate air concentrations from the determined emission rates.
The standard EN 16516 enables the evaluation of construction products regarding their emissions into indoor air under defined and comparable conditions. The evaluation includes the determination of identified target compounds, non-identified target compounds, volatile carcinogenic compounds and the sum values TVOC, TSVOC and R.
We present how mesoporosity can be engineered in transition metal phosphate (TMPs) materials in a template-free manner. The method involves the transformation of a precursor metal phosphate phase, called M-struvite (NH4MPO4·6H2O, M = Mg2+, Ni2+, Co2+, NixCo1−x2+). It relies on the thermal decomposition of crystalline M-struvite precursors to an amorphous and simultaneously mesoporous phase, which forms during degassing of NH3 and H2O. The temporal evolution of mesoporous frameworks and the response of the metal coordination environment were followed by in situ and ex situ scattering and diffraction, as well as X-ray spectroscopy. Despite sharing the same precursor struvite structure, different amorphous and mesoporous structures were obtained depending on the involved transition metal. We highlight the systematic differences in absolute surface area, pore shape, pore size, and phase transitions depending on the metal cation present in the analogous M-struvites. The amorphous structures of thermally decomposed Mg-, Ni- and NixCo1−x-struvites exhibit high surface areas and pore volumes (240 m2 g−1 and 0.32 cm−3 g−1 for Mg and 90 m2 g−1 and 0.13 cm−3 g−1 for Ni). We propose that the low-cost, environmentally friendly M-struvites could be obtained as recycling products from industrial and agricultural wastewaters. These waste products could be then upcycled into mesoporous TMPs through a simple thermal treatment for further application, for instance in (electro)catalysis.
In industrialised countries more than 80% of the time is spent indoors. Products, such as building materials and furniture, emit volatile organic compounds (VOCs), which are therefore ubiquitous in indoor air. VOC in combination may, under certain environmental and occupational conditions, result in reported sensory irritation and health complaints. Emission concentrations can become further elevated in new or refurbished buildings where the rate of air exchange with fresh ambient air may be limited due to improved energy saving aspects. A healthy indoor environment can be achieved by controlling the sources and by eliminating or limiting the release of harmful substances into the air. One way is to use (building) materials proved to be low emitting. Meanwhile, a worldwide network of professional commercial and non-commercial laboratories performing emission tests for the evaluation of products for interior use has been established. Therefore, comparability of test results must be ensured. A laboratory’s proficiency can be proven by internal and external validation measures that both include the application of suitable emission reference materials (ERM). For the emission test chamber procedure according to EN 16516, no artificial ERM is commercially available. The EU-funded EMPIR project MetrIAQ aims to fill this gap by developing new and improved ERMs. The goal is to obtain a material with a reproducible and temporally constant compound release (less than 10% variability over 14 days). Different approaches, such as the impregnation of porous materials, are being tested. The generation as well as results of the most promising materials will be presented.