Fast SARS-CoV-2 Variant Detection Using Snapback Primer High-Resolution Melting

SARS-CoV-2, the virus responsible for COVID-19, emerged in late 2019 and has since spread throughout the world, infecting over 200 million people. The fast spread of SARS-CoV-2 showcased the need for rapid and sensitive testing methodologies to help track the disease. Over the past 18 months, numerous SARS-CoV-2 variants have emerged. Many of these variants are suggested to be more transmissible as well as less responsive to neutralization by vaccine-induced antibodies. Viral whole-genome sequencing is the current standard for tracking these variants. However, whole-genome sequencing is costly and the technology and expertise are limited to larger reference laboratories. Here, we present the feasibility of a fast, inexpensive methodology using snapback primer-based high-resolution melting to test for >20 high-consequence SARS-CoV-2 spike mutations. This assay can distinguish between multiple variant lineages and be completed in roughly 2 h for less than $10 per sample.

Experience with the Introduction of SAFT Testing in Volume Production of Large Forged Parts

Large rotor forged parts, which are usually one of the most critical components in land-based turbines and generators for power generation, require a complex volumetric test for a sufficient service life. This is usually performed manually or automatically with ultrasound. New requirements, designs and materials require more sensitive testing. This can be achieved by SAFT, also called ultrasound computer tomography. SAFT is based on the Synthetic Aperture Radar (SAR) and has been further developed by several universities. The introduction of SAFT in the volume production of large forged parts was achieved by the introduction of the quantitative SAFT developed by Siemens, also called AVG or DGS-SAFT, which allows an evaluation of each voxel in units of a replacement reflector, and by an acceleration that allows the reconstruction of the complete volume of a large forged component, which could be obtained when the SAFT test was introduced into volume production. The challenges for level 2/3 reviewers are discussed, such as volume-corrected display of results, handling of large amounts of data, focusing of displays, amplitude representation in units of a replacement reflector and handling of the software. Furthermore, it is shown how displays are represented by SAFT, how the detection limit can be determined in the case of quantitative SAFT, and which artifacts can occur during series testing with SAFT.

An Electrochemical Immunosensor Based on Reduced Graphene Oxide/Multiwalled Carbon Nanotubes/Thionine/Gold Nanoparticles nanocomposites for the Sensitive Testing of Follicle-Stimulating Hormone

Follicle-Stimulating Hormone (FSH) is a kind of gonadotropin which can promote human reproduction and development. Abnormal FSH level may lead to endocrine disorder and infertility. Sensitive determination of FSH is...

DNA/RNA Electrochemical Biosensing Devices a Future Replacement of PCR Methods for a Fast Epidemic Containment

Pandemics require a fast and immediate response to contain potential infectious carriers. In the recent 2020 Covid-19 worldwide pandemic, authorities all around the world have failed to identify potential carriers and contain it on time. Hence, a rapid and very sensitive testing method is required. Current diagnostic tools, reverse transcription PCR (RT-PCR) and real-time PCR (qPCR), have its pitfalls for quick pandemic containment such as the requirement for specialized professionals and instrumentation. Versatile electrochemical DNA/RNA sensors are a promising technological alternative for PCR based diagnosis. In an electrochemical DNA sensor, a nucleic acid hybridization event is converted into a quantifiable electrochemical signal. A critical challenge of electrochemical DNA sensors is sensitive detection of a low copy number of DNA/RNA in samples such as is the case for early onset of a disease. Signal amplification approaches are an important tool to overcome this sensitivity issue. In this review, the authors discuss the most recent signal amplification strategies employed in the electrochemical DNA/RNA diagnosis of pathogens.

Hepatitis E virus (HEV)—The Future

Hepatitis (HEV) is widely distributed in pigs and is transmitted with increasing numbers to humans by contact with pigs, contaminated food and blood transfusion. The virus is mostly apathogenic in pigs but may enhance the pathogenicity of other pig viruses. In humans, infection can lead to acute and chronic hepatitis and extrahepatic manifestations. In order to stop the emerging infection, effective counter-measures are required. First of all, transmission by blood products can be prevented by screening all blood donations. Meat and sausages should be appropriately cooked. Elimination of the virus from the entire pork production can be achieved by sensitive testing and elimination programs including early weaning, colostrum deprivation, Caesarean delivery, embryo transfer, treatment with antivirals, protection from de novo infection, and possibly vaccination. In addition, contaminated water, shellfish, vegetables, and fruits by HEV-contaminated manure should be avoided. A special situation is given in xenotransplantation using pig cells, tissues or organs in order to alleviate the lack of human transplants. The elimination of HEV from pigs, other animals and humans is consistent with the One Health concept, preventing subclinical infections in the animals as well as preventing transmission to humans and disease.