Insights from MDPI Top 5 Picks: October

From molecular knot factories to positronium detection, last month we saw a wide range of topics make it into our top 5 most read articles. We connected with some of the authors of these papers to explain the impact of their research and why it is so important.

1. Experimental Study on Positronium Detection under Millimeter Waves Generated from Plasma Wakefield Acceleration – Electronics

“In this study, instead of PET imaging equipment, which is widely used in nuclear medicine, mmW and Cherenkov radiation (CR) were generated using the ponderomotive force principle in the plasma wakefield state, and electrons and positrons were generated simultaneously using a relativistic electron beam without using a PET device. We attempted to confirm the possibility of Ps photoconversion technology under electromagnetic mmW resonance conditions through experimental research where an unstable state is created and positrons occur simultaneously. Here, a relativistic electron beam energy of 0.5 ~ MeV was used, and the mmW frequency was in the G-band. A three-stepped axicon lens with a mode conversion function of electromagnetic mmW was used to apply optical conversion technology. Thus, it was possible to confirm light emission in the form of a light-converted Bessel beam.”

  • Excerpt from article

2. Shotgun Metagenomic Sequencing to Assess Cyanobacterial Community Composition following Coagulation of Cyanobacterial Blooms – Toxins

“Although mesocosm experiments have been conducted over many years to explore relationships between environmental factors and toxin concentrations, these have often focused solely on long-term scales or the lab scale. There is a need to investigate proposed short-term coagulant addition solutions and their potential impact on toxin concentration. Moreover, high-throughput sequencing approaches are considered to gain insight into the change in the cyanobacterial community composition dynamics before and after the addition of a coagulant. Furthermore, short-term dynamics are important to understand for drinking water treatment plant operation. Mesocosms offer a semi-controlled environment in the source water for understanding these dynamics.”

  • Statement from Dr. Kim Thien Nguyen Le

3. Dietary Fats and Cardio-Metabolic Outcomes in a Cohort of Italian Adults – Nutrients

In the current study, we investigated the relationship between dietary fat subtype intake and cardio-metabolic risk factors in a cohort of Mediterranean adults. Interestingly, total SFA consumption was not detrimentally associated with any cardio-metabolic outcomes; conversely, individuals who had higher intake of total SFA were less likely to have hypertension and those who specifically consumed more SCSFA–MCSFA were less likely to have dyslipidemia and diabetes. Although SFAs have been assumed to be the main nutritional risk factor for cardio-metabolic diseases, recent studies have provided new controversial and interesting evidence suggesting that the SFA–CVD relationship may not be as strong as initially thought. A recent systematic review by the Cochrane group reported that a reduction in the intake of SFAs induced a 17% lowering of the risk of cardiovascular disease and that the beneficial effects increase when SFAs are replaced with PUFAs or starchy food [23]. However, cutting SFAs had a null effect on the other CVD end-points investigated and, furthermore, the putative adverse effect of SFAs on CVD events became non-significant when the analysis included only clinical trials that had successfully reduced SFA intake while removing those that were not successful [24].”

  • Excerpt taken from article

4. Knot Factories with Helical Geometry Enhance Knotting and Induce Handedness to Knots – Polymers

“For about a century, molecular chirality has been a source of scientific discoveries and fascination. Chirality is a topological property, where chiral molecules can give rise to two molecules with mirrored geometries that cannot be superimposed by rearranging a molecule’s constituents without interrupting a bond. The most common chiral molecules are a result of chemical chirality determined by the arrangement of atoms and chemical bonds forming a molecule. Within the last decade, a new type of chiral molecule has become the focus of researchers that is formed by molecular knots. Molecular knots, such as knotted DNAs, are sometimes called chiral superstructures. The chirality of molecular knots is only one of the topological properties of the molecule characterized by handedness, while the knotted state requires characterization by more complex mathematical invariants.

Molecular knots occur naturally on DNA molecules as result of biological processes in the cell or they emerge naturally as self-entanglements on long polymer chains. The topological state of a molecule greatly affects the bio-physical properties of the molecule, and can be detrimental to the cell. That’s why it is important to study molecular knots. Methods for the preparation of sufficient amounts of well-defined knots are, however, still very limited. Knots can be induced by mechanical manipulations in single molecular experiments, or in the case of small-knotted molecules they can be prepared, due to the advances in chemical synthesis, by employing template reactions. Larger knots are usually artificially produced by inducing self-entanglements to the chain by physical mechanisms. Novel nanotechnological devices called knot factories produce knotted molecules as a result of the interplay between physical properties of the molecule, confinement strength and external force perturbing the chain.

When it comes to molecular experiments, a great deal of help comes from computer simulations, which became an indispensable tool along with theory and classical experiments. While the experimental realization of knotted molecules with defined properties is currently complicated, the knotted molecules are easily achievable in computer experiments employing molecular simulations. Therefore, molecular simulations of knotted molecules have great potential to contribute to the exploration of knotted molecules. A similar situation has already happened in the case of graphene, where thousands of computer simulations and theoretical works existed before graphene was experimentally prepared.

Therefore, in this work, computer molecular simulations were used to explore the potential of knot factories with a helical geometry to produce knots with a preferred handedness. The computational methods show how to create a new type of nano-channel that help to study not only chiral superstructures but also the effects of chiral environments. This methodology also shows how to decouple the handedness of knots from the handedness of the chain using available topology software tools. Last but not the least, the performed computer experiments showed that knots with a preferred chirality in terms of average writhe can be produced by using channels with a chosen handedness, which can be useful in designing future processes for mass producing knotted molecules with well-defined topological properties.”

  • Statement from Dr. Dušan Račko

5. New Horizons of Macrophage Immunomodulation in the Healing of Diabetic Foot Ulcers – Pharmaceutics

“Diabetic foot ulcer (DFU) is a severe public health issue and can lead to a huge socioeconomic burden. DFUs can lead to severe consequences, including lower extremity amputation and even death if inappropriately treated or left untreated. Multiple therapeutic approaches have been included in DFU management, but the unmet medical need remains large and new therapeutic strategies are urgently needed. Different subsets of macrophages participate in multiple physiological functions and disease pathologies, including DFUs. This review comprehensively describes novel macrophage-regulation approaches and the mechanisms that may or have already been proven to modulate the macrophage subsets, providing a novel and important way to promote chronic wound healing. We are also happy to see that a new approach has been developed recently. ON101, the newest clinically approved product in this setting, is designed to specifically down-regulate M1 inflammatory macrophages and further modulate the wound microenvironment to favor regenerative M2 emergence and expansion. Finally, the recent evolution of macrophage modulation therapies and techniques will improve the effectiveness of the treatment of diverse DFUs. Our ultimate goal is to review the macrophage regulation treatments and share insights with clinicians.”

    • Statement from Dr. Ming-Liang Kuo and Dr. Shyi-Gen Chen

If you want to know more about any of the studies mentioned in this article, you can read them for free on the MDPI website.