High-Resolution Petrographic Evidence Confirming Detrital and Biogenic Magnetites as Remanence Carriers for Zongpu Carbonates in the Gamba Area, South Tibet

Paleocene carbonates from the Gamba area of South Tibet provide the largest paleomagnetic dataset for constraining the paleogeography of the India-Asia collision in the early stage. Previous studies argued that the characteristic remanences (ChRMs) obtained from this unit were remagnetized via orogenic fluids. This study carries out a high-resolution petrographic study on the Paleocene carbonates from Gamba aiming to test the nature of the ChRMs. Electron microscopic observation on magnetic extracts identified a large amount of detrital magnetite that are multi- to single domain in sizes and nanoscale biogenic magnetite. Minor framboidal iron oxides were also identified, which were previously interpreted as authigenic magnetite that substitutes pyrite. However, our scanning and transmission electron microscopic (SEM/TEM) observations, along with optical microscope and Raman spectrum investigations further suggest that these magnetic minerals are pigmentary hematite and goethite that are incapable of carrying a stable primary magnetization. We therefore argue that the ChRMs of the limestones from the Zongpu Formation in the Gamba area are carried by detrital and biogenic magnetites rather than authigenic magnetite. The paleomagnetic data from the Gamba area are interpreted as primary origin and can thus be used for tectonic reconstructions. We emphasize that magnetic extraction, integrated with advanced mineralogic studies (e.g., electron backscatter diffraction and electron diffraction) are effective approaches for investigating the origin of magnetic carriers in carbonate rocks.

Photocatalytic Degradation of Antibiotics by Superparamagnetic Iron Oxide Nanoparticles. Tetracycline Case

The challenges associated with the uncontrolled presence of antibiotics such as tetracycline in the environment have necessitated their removal through different techniques. Tetracycline is hard to degrade in living organisms and can even be converted to more toxic substances. In view of this, we synthesized iron oxide nanoparticles with good magnetization (70 emu g−1) and 15 nm particle size for the adsorption and photocatalytic degradation of tetracycline. Characterization carried out on the synthesized iron oxides revealed a bandgap of 1.83 eV and an isoelectric point at pH 6.8. The results also showed that the pH of the solution does not directly influence the adsorption of tetracycline. The adsorption isotherm was consistent with the model proposed by Langmuir, having 97 mg g−1 adsorption capacity. Combined with the superparamagnetic behavior, this capacity is advantageous for the magnetic extraction of tetracycline from wastewater. The mechanisms of adsorption were proposed to be hydrogen bonding and n-π interactions. Photocatalytic degradation studies showed that approximately 40% of tetracycline degraded within 60 min of irradiation time with UV/vis light. The kinetics of photodegradation of tetracycline followed the pseudo-first-order mechanism, proceeding through hydroxyl radicals generated under illumination. Moreover, the photogenerated hydrogen peroxide could lead to heterogeneous photo-Fenton processes on the surface of iron oxide nanoparticles, additionally generating hydroxyl and hydroperoxyl radicals and facilitating photodegradation of tetracycline.

Fabrication of chitosan-coated mixed spinel ferrite integrated with graphene oxide (GO) for magnetic extraction of viral RNA for potential detection of SARS-CoV-2

Genetic variants of the COVID-19 causative virus have been arising and circulating globally. In many countries especially in developing ones with a huge population, vaccination has become one of the major challenges. SARS-CoV-2 variants’ fast transmission rate has upsurge the COVID cases, leading to more stress on health systems. In the current COVID-19 scenario, there is the requirement of more adequate diagnostic approaches to check the COVID-19 spread. Out of many diagnostic approaches, a magnetic nanoparticle-based reverse transcription-polymerase chain reaction could be nontrivial. The use of magnetic nanoparticles to separate nucleic acid of SARS-CoV-2 from the patient samples and applied for detection is an easy and more effective way for COVID-19 patient detection. Herein, the magnetic nanoparticles are synthesized using the sol-gel autocombustion methods and then, successfully coated with biopolymer (chitosan) using ultra-sonication. Chitosan-coated nanoparticles are successfully integrated into the graphene oxide sheets to introduce carboxyl groups. Crystallite size calculation, morphological and magnetic studies of synthesized magnetic nanoparticles, and multifunctional magnetic nanoparticles are done using XRD, SEM, TEM, and VSM respectively. Besides the potentiality of the fabricated nanocomposites in RNA extraction protocol is also discussed with schematic representation.

Simplified Magnetic Bead Based Viral RNA Extraction for Rapid Detection of COVID-19

Rapid and large-scale diagnosis has helped in mitigation the recent ongoing pandemic of corona virus disease of 2019 (COVID-19). The pandemic had a devastating effect on global economy. The molecular detection system has evolved over last two decades and is rapidly replacing the conventional confirmatory techniques in diagnostic virology. However the major limitation in implementation of available molecular detection assays is the non availability of field deployable nucleic acid isolation platform. The standard laboratory diagnosis rely on confirmation of presence of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in respiratory specimens of suspected patients. Preparation of viral nucleic acid is a critical step involved followed by downstream molecular diagnostic platforms. For good quality of viral RNA extraction many commercial extraction kits, are available. These are developed in a surge of pandemic scenario keeping in view the large demand for testing. The commercial RNA extraction kits available on either column based or magnetic extraction are limited and, alternative, non-commercial protocols are rapidly required. Here, we have standardized an in-house magnetic bead RNA extraction method which utilises simple in-house reagents and manual extraction method that doesn’t require any high-end equipments. The in-house assay was evaluated against the commercial available silica column and magnetic extraction kits using a panel of 100 throat /nasal swab samples. A high correlation in viral RNA detection with TaqMan qRT-PCR was observed with excellent sensitivity and specificity. Interestingly, the developed method is very simple, cost effective, rapid and can be quickly add up any downstream amplification platform for SARS-CoV-2 detection.

Iron can be microbially extracted from Lunar and Martian regolith simulants and 3D printed into tough structural materials

In-situ resource utilization (ISRU) is increasingly acknowledged as an essential requirement for the construction of sustainable extra-terrestrial colonies. Even with decreasing launch costs, the ultimate goal of establishing colonies must be the usage of resources found at the destination of interest. Typical approaches towards ISRU are often constrained by the mass and energy requirements of transporting processing machineries, such as rovers and massive reactors, and the vast amount of consumables needed. Application of self-reproducing bacteria for the extraction of resources is a promising approach to reduce these pitfalls. In this work, the bacterium Shewanella oneidensis was used to reduce three different types of Lunar and Martian regolith simulants, allowing for the magnetic extraction of iron-rich materials. The combination of bacterial treatment and magnetic extraction resulted in a 5.8-times higher quantity of iron and 43.6% higher iron concentration compared to solely magnetic extraction. The materials were 3D printed into cylinders and the mechanical properties were tested, resulting in a 400% improvement in compressive strength in the bacterially treated samples. This work demonstrates a proof of concept for the on-demand production of construction and replacement parts in space exploration.

Ultra-fast, high throughput and inexpensive detection of SARS-CoV-2 seroconversion

ABSTRACTA technique allowing high throughput, fast and low-cost quantitative analysis of human IgG antibodies reacting to SARS-CoV-2 antigens will be required to understand the levels of protecting antibodies in the population raised in response to infections and/or to immunization. We described previously a fast, simple, and inexpensive Ni2+ magnetic bead immunoassay which allowed detection of human antibodies reacting against the SARS-CoV-2 nucleocapsid protein using a minimal amount of serum or blood. A major drawback of the previously described system was that it only processed 12 samples simultaneously. Here we describe a manually operating inexpensive 96 well plate magnetic extraction / homogenization process which allows high throughput analysis delivering results of 96 samples in chromogenic format in 12 minutes or in fluorescent ultrafast format which takes only 7 minutes. We also show that His tag antigen purification can be performed on the fly while loading antigens to the Ni2+ magnetic beads in a process which takes only 12 min reducing the pre analytical time and cost. Finally, we show that the magnetic bead immunoassay is antigen flexible and can be performed using either Nucleocapsid, Spike or Spike RBD. The method performed with low inter and intra assay variability using different antigens and detection modes and was able to deliver >99.5% specificity and >95% sensitivity for a cohort of 203 pre pandemic and 63 COVID-19 positive samples.

Detection of chronic wasting disease in mule and white-tailed deer by RT-QuIC analysis of outer ear

Efforts to contain the spread of chronic wasting disease (CWD), a fatal, contagious prion disease of cervids, would be aided by the availability of additional diagnostic tools. RT-QuIC assays allow ultrasensitive detection of prion seeds in a wide variety of cervid tissues, fluids and excreta. The best documented antemortem diagnostic test involving RT-QuIC analysis targets lymphoid tissue in rectal biopsies. Here we have tested a more easily accessed specimen, ear pinna punches, using an improved RT-QuIC assay involving iron oxide magnetic extraction to detect CWD infections in asymptomatic mule and white-tailed deer. Comparison of multiple parts of the ear pinna indicated that a central punch spanning the auricular nerve provided the most consistent detection of CWD infection. When compared to results obtained from gold-standard retropharyngeal lymph node specimens, our RT-QuIC analyses of ear samples provided apparent diagnostic sensitivity (81%) and specificity (91%) that rivaled, or improved upon, those observed in previous analyses of rectal biopsies using RT-QuIC. These results provide evidence that RT-QuIC analysis of ear pinna punches may be a useful approach to detecting CWD infections in cervids.