Applied Research最新文献

This study examines the performance of a microbial fuel cell (MFC) utilizing Shewanella bacteria through electrochemical impedance spectroscopy (EIS). Exo-electrogen bacteria are key agents in an MFC. Shewanella sp. as a common exo-electrogen bacteria can transfer electrons from the cell surface through different electron transfer mechanisms. In this work, EIS was used to probe the effects of biofilms of Shewanella sp. and the solution of 10% V/V Shewanella on the MFC performance. This research investigates the effects of both microbial biofilms and Shewanella bacterial solutions on MFC efficacy. Findings revealed that biofilm formation on the anode surface significantly reduces anode charge transfer resistance, thereby enhancing power generation. Notably, a 10% Shewanella solution resulted in a 25% higher power density compared to the biofilm. Furthermore, the MFC demonstrated up to 80% chemical oxygen demand removal efficiency in treating brewery wastewater. The study underscores the viability of Shewanella bacterial solutions as an efficient alternative to biofilms, emphasizing their role in improving MFC performance and wastewater treatment efficiency.

The use of pesticides is an important practice in today's agricultural and nutritional supply chain worldwide. Their potentially harmful effects require rapid and reliable monitoring. As an emerging technology, surface-enhanced Raman spectroscopy (SERS) is paving its way through established methodologies. The Raman enhancing effect is based on the interaction of the analyte and nanoparticles prepared from noble metals. To better support and exploit analytical applications, the interaction between gold nanoparticles and the pesticide paraquat were studied. To this purpose, molecular dynamic calculations were performed with paraquat on single-crystal structures of gold at a distance of 3.4 Å and an intramolecular dihedral angle of 18.8° between the two paraquat ring systems. The molecular dynamic calculations showed that the two noble metal surface models exhibited only slight differences in their effects on paraquat. Experimental SERS spectra with gold nanoparticles were recorded and compared to the experimental Raman spectrum. The observed differences were further investigated using density functional theory calculations and reducing the gold cell to a gold cluster of 20 atoms. A co-planar orientation of paraquat to the gold cluster surface was thereby deduced. Based on an optimized paraquat geometry including a dihedral angle of 36.77° at a distance of 3.85 Å to the gold cluster, an excellent agreement between computed and experimental spectra was obtained. A head-on geometry was discarded due to spectral mismatch. This computational approach may help to analyze SERS spectra and make SERS further suitable for pesticide analysis.

Crystallographic fragment screening (CFS) has recently matured into an important method for the early stages of drug discovery projects. It is based on high-throughput structure determination and thus requires a high degree of automation as well as specialized workflows and robust analysis tools. Consequently, large-scale research facilities such as synchrotrons have embraced the method, and developed platforms to perform CFS campaigns with the help of crystallography experts and specific tools. The BESSY II synchrotron, operated by the Helmholtz–Zentrum Berlin (HZB), is one of these synchrotron facilities that offer a CFS platform, named the F2X-facility. Here, the specialized F2X workflow is described along with the relevant differences to other existing CFS platforms, and the ongoing developments aimed at supporting users of the facility. The different stages of a CFS campaign including requirements, beamline capabilities, and the software environment are detailed and explained. A unique F2X-GO kit is featured, which allows users the possibility of performing all sample preparation in their home laboratories. Furthermore, at the HZB a computational workflow has been built to support users beyond the hit identification stage. The advantages of the F2X-facility at HZB are described and references are provided to successfully conduct CFS.

Infrared thermography (IRT) using a focused laser is effective for surface defect detection. Nevertheless, testing complex-shaped components remains a challenging task. The state-of-the-art focuses on testing a limited region of interest rather than the full sample. Thus, detection and location of surface defects has been less researched. Most attempts require a manual scan of the full sample, which makes it hard to reconstruct the full scanned surface. Here, we introduce a reliable workflow for crack detection and semi-automated inspection of complex-shaped components using IRT excited with a laser line. A 6-axis robot arm is used for moving the sample in front of the setup. This approach has been tested on a section of a rail and a gear, both containing defects due to heavy use. Crack detection is based on the segmentation of thermograms obtained by Fourier transform of sorted temperatures. Moreover, texture mapping is used to visualize a reconstructed thermogram on the 3D model of the sample. Our approach illustrates a reliable process towards the digitalization of thermographic testing.

Nymphaea caerulea (Blue water lily) is an esthetically pleasing aquatic plant which is widely located across India and Africa. The blue water lily contains an alkaloid called apomorphine which is said to be a sedative, and a nonselective dopamine agonist and is now available in the local and online market in the form of powders and oils for various applications such as sleeping aid, anxiety reliever and sexual performance enhancer. These properties are abused by the consumption of Nymphaea caerulea to achieve a state of “high” which has led the categorization of the same as a novel psychoactive substance. In this paper, a rapid mass spectral analysis was performed for the preliminary screening of commercially available blue water lily products using the Waters Radian as soon as possible instrument, followed by the high performance liquid chromatography-photo diode array method development and validation of the samples for the qualitative and quantitative analysis of apomorphine. Accelerated solvent extraction as a green alternative to the conventional soxhlet extraction was used in the extraction of the plant material. The method was finally screened for its greenness using the Complex green analytical procedure index method. The method was validated with a linearity of 0.9973; limit of detection and limit of quantitation of 0.02 and 0.18 µg/mL, respectively. The method was able to detect and quantitate apomorphine in two samples from the commercially available natural products of Nymphaea caerulea.

Since cell-based virus neutralization assays are still the gold standard to assess a patient's immune protection against a given virus, they are of utmost importance for serodiagnosis, convalescent plasma therapy, and vaccine development. Monitoring the emergence and characteristics of neutralizing antibodies in an outbreak situation, confirming neutralizing antibodies as correlates of protection from infection and testing vaccine-induced potency of neutralizing antibody responses, quests for automated, fast, and parallel neutralization assays. We developed an impedance-based sensor platform (electric cell-substrate impedance sensing, ECIS) providing time-resolved monitoring of the host cell response to viral pseudotypes. For validation, the impedance assay was compared with state-of-the-art quantification of virus-induced reporter protein expression as an independent indicator of virus infection and neutralization. Vesicular stomatitis virus (VSV) derived pseudoviruses encoding the green fluorescent protein (GFP) as reporter and the autologous G protein (VSV-G) for the initial binding to the host cell membrane were used for monitoring of HEK293T cell infection and neutralization with both, impedance and optical readout. Virus-induced cytopathic effects (CPE) were detectable for low pseudotype concentrations (multiplicity of infection 1) in time-resolved impedance profiles as soon as 5–10 h after infection in a concentration-dependent manner. Neutralization efficacy of α-VSV-G antibodies was determined from impedance time courses and IC₅₀ values compared favorably with fluorescence measurements of virus-borne GFP expression. Sera of convalescent COVID-19 patients were tested successfully for SARS-CoV-2 neutralizing antibodies by incubating VSV, pseudotyped with the SARS-CoV-2 spike protein, with different sera before host cell exposure and impedance recordings. In summary: (i) ECIS monitoring was successfully applied to detect virus-mediated cell infection and neutralization; (ii) Impedance-based monitoring allows reducing the assay time to 5–10 h; and (iii) the platform is easily adapted to other virus-based diseases and scalable to high-throughput.