Erscheinungsjahr 2021

Anzahl der Treffer: 85
Erstellt: Thu, 28 Mar 2024 23:15:19 +0100 in 0.0680 sec


Visaveliya, Nikunjkumar R.; Köhler, Michael
Softness meets with brightness: dye-doped multifunctional fluorescent polymer particles via microfluidics for labeling. - In: Advanced optical materials, ISSN 2195-1071, Bd. 9 (2021), 13, 2002219, insges. 22 S.

Fluorogenic labeling strategies have emerged as powerful tools for in vivo and in vitro imaging applications for diagnostic and theranostic purposes. Free organic chromophores (fluorescent dyes) are bright but rapidly degrade. Inorganic nanoparticles (e.g., quantum dots) are photostable but toxic to biological systems. Alternatively, dye-doped polymer particles are promising for labeling and imaging due to their properties that overcome limitations of photodegradation and toxicity. This progress report, therefore, presents various synthesis techniques for the generation of dye-doped fluorescent polymer particles. Polymer particles are relatively soft compared to inorganic nanoparticles and can be synthesized with characteristics like biocompatibility and stimuli responsiveness. Also, their ability of loading fluorophores through various interactions reveals brightness. Here, a multiscale-multicolor library of bright and soft fluorescent polymer particles is generated hierarchically. Various microfluidic supported strategies have been applied where fluorophores can be linked to polymeric networks noncovalently and covalently in the interior, and at the surface of nanoparticles (60-550 nm). Besides, microfluidic strategies for hydrophilic and hydrophobic fluorescent polymer microparticles (20-800 [my]m) have been performed for systematic tuning in size and color combination. Furthermore, soft and bright particulate assemblies are enabled through interfacial interactions at the intermediate scale (600 nm-3 [my]m) between the nanometer and micrometer lengthscale.



https://doi.org/https://doi.org/10.1002/adom.202002219
Mäder, Patrick; Boho, David; Rzanny, Michael Carsten; Seeland, Marco; Wittich, Hans Christian; Deggelmann, Alice; Wäldchen, Jana
The Flora Incognita app - interactive plant species identification. - In: Methods in ecology and evolution, ISSN 2041-210X, Bd. 12 (2021), 7, S. 1335-1342

Being able to identify plant species is an important factor for understanding biodiversity and its change due to natural and anthropogenic drivers. We discuss the freely available Flora Incognita app for Android, iOS and Harmony OS devices that allows users to interactively identify plant species and capture their observations. Specifically developed deep learning algorithms, trained on an extensive repository of plant observations, classify plant images with yet unprecedented accuracy. By using this technology in a context-adaptive and interactive identification process, users are now able to reliably identify plants regardless of their botanical knowledge level. Users benefit from an intuitive interface and supplementary educational materials. The captured observations in combination with their metadata provide a rich resource for researching, monitoring and understanding plant diversity. Mobile applications such as Flora Incognita stimulate the successful interplay of citizen science, conservation and education.



https://doi.org/10.1111/2041-210X.13611
Köcher, Chris;
Reachability problems on reliable and lossy queue automata. - In: Theory of computing systems, ISSN 1433-0490, Bd. 65 (2021), 8, S. 1211-1242

We study the reachability problem for queue automata and lossy queue automata. Concretely, we consider the set of queue contents which are forwards resp. backwards reachable from a given set of queue contents. Here, we prove the preservation of regularity if the queue automaton loops through some special sets of transformation sequences. This is a generalization of the results by Boigelot et al. and Abdulla et al. regarding queue automata looping through a single sequence of transformations. We also prove that our construction is possible in polynomial time.



https://doi.org/10.1007/s00224-021-10031-2
Köhler, Michael; Beetz, Nancy; Günther, Mike; Möller, Frances; Cao-Riehmer, Jialan
Extremophiles in soil communities of former copper mining sites of the East Harz region (Germany) reflected by re-analyzed 16S rRNA data. - In: Microorganisms, ISSN 2076-2607, Bd. 9 (2021), 7, 1422, insges. 16 S.

The east and southeast rim of Harz mountains (Germany) are marked by a high density of former copper mining places dating back from the late 20th century to the middle age. A set of 18 soil samples from pre- and early industrial mining places and one sample from an industrial mine dump have been selected for investigation by 16S rRNA and compared with six samples from non-mining areas. Although most of the soil samples from the old mines show pH values around 7, RNA profiling reflects many operational taxonomical units (OTUs) belonging to acidophilic genera. For some of these OTUs, similarities were found with their abundances in the comparative samples, while others show significant differences. In addition to pH-dependent bacteria, thermophilic, psychrophilic, and halophilic types were observed. Among these OTUs, several DNA sequences are related to bacteria which are reported to show the ability to metabolize special substrates. Some OTUs absent in comparative samples from limestone substrates, among them Thaumarchaeota were present in the soil group from ancient mines with pH > 7. In contrast, acidophilic types have been found in a sample from a copper slag deposit, e.g., the polymer degrading bacterium Granulicella and Acidicaldus, which is thermophilic, too. Soil samples of the group of pre-industrial mines supplied some less abundant, interesting OTUs as the polymer-degrading Povalibacter and the halophilic Lewinella and Halobacteriovorax. A particularly high number of bacteria (OTUs) which had not been detected in other samples were found at an industrial copper mine dump, among them many halophilic and psychrophilic types. In summary, the results show that soil samples from the ancient copper mining places contain soil bacterial communities that could be a promising source in the search for microorganisms with valuable metabolic capabilities.



https://doi.org/10.3390/microorganisms9071422
Nozdrenko, Dmytro; Matvienko, Tetiana; Vygovska, Oksana; Bogutska, Kateryna; Motuziuk, Olexandr; Nurishchenko, Natalia; Prylutskyy, Yuriy; Scharff, Peter; Ritter, Uwe
Protective effect of water-soluble C60 fullerene nanoparticles on the ischemia-reperfusion injury of the muscle soleus in rats. - In: International journal of molecular sciences, ISSN 1422-0067, Bd. 22 (2021), 13, 6812, S. 1-13

The biomechanical parameters of muscle soleus contraction in rats and their blood biochemical indicators after the intramuscular administration of water-soluble C60 fullerene at doses of 0.5, 1, and 2 mg/kg 1 h before the onset of muscle ischemia were investigated. In particular, changes in the contraction force of the ischemic muscle soleus, the integrated power of the muscle, the time to achieve the maximum force response, the dynamics of fatigue processes, and the parameters of the transition from dentate to smooth tetanus, levels of creatinine, creatine kinase, lactate and lactate dehydrogenase, and parameters of prooxidant-antioxidant balance (thiobarbituric acid reactive substances, hydrogen peroxide, and reduced glutathione and catalase) were analyzed. The positive therapeutic changes in the studied biomechanical and biochemical markers were revealed, which indicate the possibility of using water-soluble C60 fullerenes as effective prophylactic nanoagents to reduce the severity of pathological conditions of the muscular system caused by ischemic damage to skeletal muscles.



https://doi.org/10.3390/ijms22136812
Weigert, Florian; Hebenstreit, Roman; Füßl, Roland; Theska, René
Experimental setup for the investigation of reproducibility of novel tool changing systems in nanofabrication machines. - In: Nanomanufacturing and metrology, ISSN 2520-8128, Bd. 4 (2021), 3, S. 181-189

Nanomeasuring machines developed at the Technische Universität Ilmenau enable three-dimensional measurements and manufacturing processes with the lowest uncertainties. Due to the requirements for these processes, a highly reproducible and long-term stable tool changing system is needed. For this purpose, kinematically determined couplings are widely used. The state-of-the-art investigations on those are not sufficient for the highest demands on the reproducibility required for this application. A theoretical determination of the reproducibility based on analytical or numerical methods is possible, however not in the desired nanometer range. Due to this, a measurement setup for the determination of the reproducibility in five degrees of freedom with nanometer uncertainty was developed. First, potential measuring devices are systematically examined and measurement principles were developed out of this. A three-dimensional vector-based uncertainty analysis is performed to prove the feasibility of the measurement principle and provides a basis for further design. As a result, a translatory measurement uncertainty of 10 nm and a rotatory uncertainty of 11 nrad can be reached. Afterwards, the measurement setup is designed, focusing on the metrological frame and the lift-off device. The developed setup exceeds the uncertainties of the measurement setups presented in the state-of-the-art by an order of magnitude, allowing new in-depth investigations of the reproducibility of kinematic couplings.



https://doi.org/10.1007/s41871-021-00103-9
Straube, Guido; Fischer Calderón, Juan Sebastian; Ortlepp, Ingo; Füßl, Roland; Manske, Eberhard
A heterodyne interferometer with separated beam paths for high-precision displacement and angular measurements. - In: Nanomanufacturing and metrology, ISSN 2520-8128, Bd. 4 (2021), 3, S. 200-207

As standard concepts for precision positioning within a machine reach their limits with increasing measurement volumes, inverse concepts are a promising approach for addressing this problem. The inverse principle entails other limitations, as for high-precision positioning of a sensor head within a large measurement volume, three four-beam interferometers are required in order to measure all necessary translations and rotations of the sensor head and reconstruct the topography of the reference system consisting of fixed mirrors in the x-, y-, and z-directions. We present the principle of a passive heterodyne laser interferometer with consequently separated beam paths for the individual heterodyne frequencies. The beam path design is illustrated and described, as well as the design of the signal-processing and evaluation algorithm, which is implemented using a System-On-a-Chip with an integrated FPGA, CPU, and A/D converters. A streamlined bench-top optical assembly was set up and measurements were carried out to investigate the remaining non-linearities. Additionally, reference measurements with a commercial homodyne interferometer were executed.



https://doi.org/10.1007/s41871-021-00101-x
Cao, Xinrui; Feßer, Patrick; Sinzinger, Stefan
Lau effect using LED array for lithography. - In: Nanomanufacturing and metrology, ISSN 2520-8128, Bd. 4 (2021), 3, S. 165-174

Illumination with LEDs is of increasing interest in imaging and lithography. In particular, compared to lasers, LEDs are temporally and spatially incoherent, so that speckle effects can be avoided by the application of LEDs. Besides, LED arrays are qualified due to their high optical output power. However, LED arrays have not been widely used for investigating optical effects, e.g., the Lau effect. In this paper, we propose the application of an LED array for realizing the Lau effect by taking into account the influence of the coherence properties of illumination on the Lau effect. Using spatially incoherent illumination with the LED array or a single LED, triangular distributed Lau fringes can be obtained. We apply the obtained Lau fringes in the optical lithography to produce analog structures. Compared to a single LED, the Lau fringes using the LED array have significantly higher intensities. Hence, the exposure time in the lithography process is largely reduced.



https://doi.org/10.1007/s41871-021-00108-4
Ortlepp, Ingo; Zöllner, Jens-Peter; Rangelow, Ivo W.; Manske, Eberhard
Heterodyne standing-wave interferometer with improved phase stability. - In: Nanomanufacturing and metrology, ISSN 2520-8128, Bd. 4 (2021), 3, S. 190-199

This paper describes a standing-wave interferometer with two laser sources of different wavelengths, diametrically opposed and emitting towards each other. The resulting standing wave has an intensity profile which is moving with a constant velocity, and is directly detected inside the laser beam by two thin and transparent photo sensors. The first sensor is at a fixed position, serving as a phase reference for the second one which is moved along the optical axis, resulting in a frequency shift, proportional to the velocity. The phase difference between both sensors is evaluated for the purpose of interferometric length measurements.



https://doi.org/10.1007/s41871-021-00098-3
Weigel, Christoph; Phi, Hai Binh; Denissel, Felix Arthur; Hoffmann, Martin; Sinzinger, Stefan; Strehle, Steffen
Highly anisotropic fluorine-based plasma etching of ultralow expansion glass. - In: Advanced engineering materials, ISSN 1527-2648, Bd. 23 (2021), 6, 2001336, insges. 10 S.

Deep etching of glass and glass ceramics is far more challenging than silicon etching. For thermally insensitive microelectromechanical and microoptical systems, zero-expansion materials such as Zerodur or ultralow expansion (ULE) glass are intriguing. In contrast to Zerodur that exhibits a complex glass network composition, ULE glass consists of only two components, namely, TiO2 and SiO2. This fact is highly beneficial for plasma etching. Herein, a deep fluorine-based etching process for ULE 7972 glass is shown for the first time that yields an etch rate of up to 425 nm min^-1 while still achieving vertical sidewall angles of 87˚. The process offers a selectivity of almost 20 with respect to a nickel hard mask and is overall comparable with fused silica. The chemical surface composition is additionally investigated to elucidate the etching process and the impact of the tool configuration in comparison with previously published etching results achieved in Zerodur. Therefore, deep and narrow trenches can be etched in ULE glass with high anisotropy, which supports a prospective implementation of ULE glass microstructures, for instance, in metrology and miniaturized precision applications.



https://doi.org/10.1002/adem.202001336