Revisiting the formation mechanism for coronal rain from previous studies

Solar coronal rain is classified generally into two categories: flare-driven and quiescent coronal rain. Th latter is observed to form along both closed and open magnetic field structures. Recently, we proposed that some of the quiescent coronal rain events, detected in the transition region and chromospheric diagnostics, along loop-like paths could be explained by the formation mechanism for quiescent coronal rain facilitated by interchange magnetic reconnection between open and closed field lines. In this study, we revisited 38 coronal rain reports from the literature. From theseearlier works, we picked 15 quiescent coronal rain events out of the solar limb, mostly suggested to occur in active region closed loops due to thermal nonequilibrium, to scrutinize their formation mechanism. Employing the extreme ultraviolet images and line-of-sight magnetograms, the evolution of the quiescent coronal rain events and their magnetic fields and context coronal structures is examined. We find that six, comprising 40%, of the 15 quiescent coronal rain events could be totally or partially interpreted by the formation mechanism for quiescent coronal rain along open structures facilitated by interchange reconnection. The results suggest that the quiescent coronal rain facilitated by interchange reconnection between open and closed field lines deserves more attention.

Particle morphology of medusavirus inside and outside the cells reveals a new maturation process of giant viruses

Medusavirus, a giant virus, is phylogenetically closer to eukaryotes than the other giant viruses and has been recently classified as an independent species. However, details of its morphology and maturation process in host cells remain unclear. Here, we investigated the particle morphology of medusavirus inside and outside infected cells using conventional transmission electron microscopy (C-TEM) and cryo-electron microscopy (cryo-EM). The C-TEM of amoeba infected with the medusavirus showed four types of particles: empty, DNA-full, and the corresponding intermediates. Time-dependent changes in the proportion and following intracellular localization of these particles suggested a new maturation process for the medusavirus. Empty particles and viral DNAs were produced independently in the cytoplasm and nucleus, respectively, and only empty particles located near the nucleus incorporated the viral DNA into the capsid. All four types of particles were also found outside the cells. The cryo-EM of these particles showed that the intact capsid structure, covered with three different types of spikes, was conserved among all particle types, although with minor size-related differences. The internal membrane exhibited a structural array similar to that of the capsid, interacted closely with the capsid, and displayed open membrane structures in the empty and empty-intermediate particles. This result suggests that the open structures in the internal membrane are used for an exchange of scaffold proteins and viral DNA during the maturation process. This new model of the maturation process of medusavirus provides insight into the structural and behavioral diversity of giant viruses.

Stabilization of Lecitase Ultra® by Immobilization and Fixation of Bimolecular Aggregates. Release of Omega-3 Fatty Acids by Enzymatic Hydrolysis of Krill Oil

Lecitase Ultra® solutions are mainly composed of bimolecular aggregates of two open structures of the enzyme. The immobilization and fixation of these bimolecular aggregates onto support surfaces is here proposed as a novel protocol for the immobilization and stabilization of Lecitase. The resulting derivatives of Lecitase aggregates were much more stable than the diluted solutions of the enzyme. The most stable of them was obtained by covalent immobilization of the bimolecular aggregate: 300-fold more stable than the diluted enzyme and 75-fold more stable than open Lecitase adsorbed onto hydrophobic supports. The bimolecular aggregate that adsorbed onto polyethyleneimine-agarose exhibited the best combination of activity and stability for the hydrolysis of krill oil. Omega-3 acids are in the sn-2 position of the krill oil, but they are also released by a phospholipase A1 because of migration issues.

The role of membrane destabilisation and protein dynamics in BAM catalysed OMP folding

The folding of β-barrel outer membrane proteins (OMPs) in Gram-negative bacteria is catalysed by the β-barrel assembly machinery (BAM). How lateral opening in the β-barrel of the major subunit BamA assists in OMP folding, and the contribution of membrane disruption to BAM catalysis remain unresolved. Here, we use an anti-BamA monoclonal antibody fragment (Fab1) and two disulphide-crosslinked BAM variants (lid-locked (LL), and POTRA-5-locked (P5L)) to dissect these roles. Despite being lethal in vivo, we show that all complexes catalyse folding in vitro, albeit less efficiently than wild-type BAM. CryoEM reveals that while Fab1 and BAM-P5L trap an open-barrel state, BAM-LL contains a mixture of closed and contorted, partially-open structures. Finally, all three complexes globally destabilise the lipid bilayer, while BamA does not, revealing that the BAM lipoproteins are required for this function. Together the results provide insights into the role of BAM structure and lipid dynamics in OMP folding.

Overview of the Structure–Dynamics–Function Relationships in Borohydrides for Use as Solid-State Electrolytes in Battery Applications

The goal of this article is to highlight crucial breakthroughs in solid-state ionic conduction in borohydrides for battery applications. Borohydrides, Mz+BxHy, form in various molecular structures, for example, nido-M+BH4; closo-M2+B10H10; closo-M2+B12H12; and planar-M6+B6H6 with M = cations such as Li+, K+, Na+, Ca2+, and Mg2+, which can participate in ionic conduction. This overview article will fully explore the phase space of boron–hydrogen chemistry in order to discuss parameters that optimize these materials as solid electrolytes for battery applications. Key properties for effective solid-state electrolytes, including ionic conduction, electrochemical window, high energy density, and resistance to dendrite formation, are also discussed. Because of their open structures (for closo-boranes) leading to rapid ionic conduction, and their ability to undergo phase transition between low conductivity and high conductivity phases, borohydrides deserve a focused discussion and further experimental efforts. One challenge that remains is the low electrochemical stability of borohydrides. This overview article highlights current knowledge and additionally recommends a path towards further computational and experimental research efforts.

The role of membrane destabilisation and protein dynamics in BAM catalysed OMP folding.

The folding of β-barrel outer membrane proteins (OMPs) in Gram-negative bacteria is catalysed by the β-barrel assembly machinery (BAM). How lateral opening in the β-barrel of the major subunit BamA assists in OMP folding, and the contribution of membrane disruption to BAM catalysis remain unresolved. Here, we use an anti-BamA monoclonal antibody fragment (Fab1) and two disulphide-crosslinked BAM variants (lid-locked (LL), and POTRA-5-locked (P5L)) to dissect these roles. Despite being lethal in vivo, we show that all complexes catalyse folding in vitro, albeit less efficiently than wild-type BAM. CryoEM revealed that while Fab1 and BAM-P5L trap an open-barrel state, BAM-LL contains a mixture of closed and contorted, partially-open structures. Finally, all three complexes globally destabilise the lipid bilayer, while BamA does not, revealing that the BAM lipoproteins are required for this function. Together the results provide new insights into the role of BAM structure and lipid dynamics in OMP folding.

MODERN BELIGERATIVE RELIEF (ON THE EXAMPLE OF YAVORIV MILITARY TRAINING GROUND OF LVIV REGION)

The author establishes the types of relief created for military purposes (beligerative) and analyzes its morphology. The territory of the Yavoriv military training ground in the Lviv region, the largest in Ukraine training complex of various types and kinds of troops, was chosen as an example. The military training ground was established in the 30s of the twentieth century. In the past, Polish infantry, German tank divisions, Soviet troops, and nowadays Ukrainian and international ground and air forces trained here. The area of the landfill is 361.5 km2. It occupies an advantageous position in the terrain, as it is located on an elevated part of the Roztochchya Upland, where the Main European watershed passes. Loose sediments are widespread in the territory, which contribute to the creation of deep and elongated forms of beligerative relief. These are mainly quaternary alluvial sands and detritus of native rocks, aeolian and diluvial loess and sandy loams, alluvial sediments. We consider the beligerative relief as an integral part of the field military fortification. The research was performed on the base of interpretation of large-scale space images, aerial photographs and field studies. The modern beligerative relief observed at the Yavoriv military training ground was classified into positive and negative forms depending on the method of military activity. Positive forms include: 1) hills of command posts for control and surveillance, 2) hills of tank or cannon fortifications, 3) micro-hills of protection against small arms, 4) bunkers (wooden-earth defense points), 5) high-altitude targets and firing positions. Negative forms are as follows: 1) trenches of the defense line and the course of connections; 2) open structures for the protection of personnel: individual trenches, pairs, for several infantry, as well as for shooting lying down, kneeling, standing; 3) trenches for the protection of equipment and heavy artillery weapons; 4) closed structures for personnel protection: dugouts, bunkers, cracks, dugouts; 5) excavations from ruptures of artillery shells. There are more negative forms in the modern military relief. Analysis of space images from different times (1980–1990, 2000–2005, 2015–2019) and modern field observations allowed us to trace the dynamics of beligerative relief forms. The formation of new and most widespread forms occurs in the mid-80 of the twentieth century. At the end of the XX and at the beginning of the XXI century, the existing forms decline, steamrolled by exogenous processes, and new ones do not appear. New forms have been appeared since 2015, but only in small local areas. The place they appear are characterized by a significant anthropogenic transformation of the terrain, the development of exogenous processes, such as soil dispersal, desertification, erosion, oozing. Key words: beligerative (military) relief; Yavoriv military training ground (Ukraine); morphological classification.

Synthetic Strategies for Hollow Particles with Open Holes on Their Surfaces

Hollow particles with open holes on their surfaces, which refer to hollow micro/nano spheres with open structures such as single hole or multi-holes on their surface, have attracted increasing interest...