Open-Bundle Structure as the Unfolding Intermediate of Cytochrome c′ Revealed by Small Angle Neutron Scattering

The dynamic structure changes, including the unfolding, dimerization, and transition from the compact to the open-bundle unfolding intermediate structure of Cyt c′, were detected by a small-angle neutron scattering experiment (SANS). The structure of Cyt c′ was changed into an unstructured random coil at pD = 1.7 (Rg = 25 Å for the Cyt c′ monomer). The four-α-helix bundle structure of Cyt c′ at neutral pH was transitioned to an open-bundle structure (at pD ~13), which is given by a numerical partial scattering function analysis as a joint-clubs model consisting of four clubs (α-helices) connected by short loops. The compactly folded structure of Cyt c′ (radius of gyration, Rg = 18 Å for the Cyt c′ dimer) at neutral or mildly alkaline pD transited to a remarkably larger open-bundle structure at pD ~13 (Rg = 25 Å for the Cyt c′ monomer). The open-bundle structure was also supported by ab initio modeling.

Length-dependent motions of SARS-CoV-2 frameshifting RNA pseudoknot and alternative conformations suggest avenues for frameshifting suppression

Conserved SARS-CoV-2 RNA regions of critical biological functions define excellent targets for anti-viral therapeutics against Covid-19 variants. One such region is the frameshifting element (FSE), responsible for correct translation of viral polyproteins. Here, we analyze molecular-dynamics motions of three FSE conformations, discovered by graph-theory analysis, and associated mutants designed by graph-based inverse folding: two distinct 3-stem H-type pseudoknots and a 3-way junction. We find that the prevalent H-type pseudoknot in literature adopts ring-like conformations, which in combination with 5′ end threading could promote ribosomal pausing. An inherent shape switch from “L” to linear that may help trigger the frameshifting is suppressed in our designed mutant. The alternative conformation trajectories suggest a stable intermediate structure with mixed stem interactions of all three conformations, pointing to a possible transition pathway during ribosomal translation. These observations provide new insights into anti-viral strategies and frameshifting mechanisms.

Preparation of carbon anode sheet precursor using raw Air Laya–Bukit Asam coal and its application for battery

Research has been carried out on manufacturing carbon electrode thin sheets used as anode for solid battery cells. The material used is raw coal carbonized at 800 and 1000oC, polyvinylidene fluoride (PVDF), and N-Dimethylacetamide (DMAC) as a solvent. Observation of crystal structure by X-rays diffraction method shows a diffraction pattern where crystallites in all product samples have an intermediate structure between graphite and amorphous known as a turbostratic structure or a random layer lattice structure. The distance between the crystallite structure’s aromatic layers (d002) is in the range 3.52-3.62 Å. Aromaticity (fa) is in the range 0.42 - 0.48 for all samples. The high value of d002 indicated that the crystallinity or level of graphitization obtained by all samples was still low. Manufacturing technique using a Doctor Blade-based tape casting method. The discharge capacities of the samples reach about 60 and 18 mAh.g-1, while their charge capacities at the first cycle are 50 and 16 mAh.g1, respectively. Cyclic voltammetry (CV) was performed using anodes resulted at 0.1 to 2.3 volt. During the forward scan, CV curves of the sample reveal a reduction current starting from around 1.2 V and exhibiting two-reduction waves, between 1.2 and 0.6 V.

Non-conventional octameric structure of C-phycocyanin

C-phycocyanin (CPC), a blue pigment protein, is an indispensable component of giant phycobilisomes, which are light-harvesting antenna complexes in cyanobacteria that transfer energy efficiently to photosystems I and II. X-ray crystallographic and electron microscopy (EM) analyses have revealed the structure of CPC to be a closed toroidal hexamer by assembling two trimers. In this study, the structural characterization of non-conventional octameric CPC is reported for the first time. Analyses of the crystal and cryogenic EM structures of the native CPC from filamentous thermophilic cyanobacterium Thermoleptolyngbya sp. O–77 unexpectedly illustrated the coexistence of conventional hexamer and novel octamer. In addition, an unusual dimeric state, observed via analytical ultracentrifugation, was postulated to be a key intermediate structure in the assemble of the previously unobserved octamer. These observations provide new insights into the assembly processes of CPCs and the mechanism of energy transfer in the light-harvesting complexes.

Multicenter study: outcomes of carotid endarterectomy depending on configuration of circle of Willis

BACKGROUND: The circle of Willis (CW) is an important network of collaterals that provide compensatory redistribution of hemodynamic load. Several studies showed that the CW is open in approximately 50%90% of cases, and the number of missing segments correlates with low brain tolerance to ischemia in internal carotid artery (ICA) compression. Currently, studies dedicated to the relationship of different configurations of CW with the risk of ischemic brain damage. AIM: The analyze the immediate results of eversion carotid endarterectomy (CEA) in patients with different configurations of the structure of the CW. MATERIALS AND METHODS: We included 641 patients with hemodynamically significant stenosis of the internal carotid arteries (ICA) in a study period from 2010 to 2020. All patients underwent multispiral computed tomography with angiography of the extracranial and CW arteries. Based on the structural variants of the CW, six groups of patients were studied: group 1 (64.9%, n = 416) closed posterior part (CPP) with the existence of posterior communicative artery (PCA) and P1 segment of the posterior cerebral artery (PCerA); group 2 (27%, n = 173) an intermediate structure of the posterior part (IPP) with hypoplasia of the PCA or PCerA; group 3 (8.1%, n = 52) open posterior part (OPP) with the absence of PCA or PCerA; group 4 (85.95%, n = 551) closed anterior part (CAP) with the presence of the anterior communicating artery (ACA) and A1 segment of the anterior cerebral artery (ACerA); group 5 (7.95%, n = 51) an intermediate structure of the anterior part (IAP) with hypoplasia of ACA or ACerA; group 6 (6.1%, n = 39) open anterior part (OAP) with the absence of ACA or ACerA. To assess the compensatory potentials of the brain, all patients underwent measurement of the retrograde pressure in the ICA and intraoperative cerebral oximetry. RESULTS: In the postoperative period, 1 death was recorded in group 4 (CAP) due to a hemorrhagic transformation in the zone of ischemic stroke, on the background development of hyperperfusion syndrome. The largest number of ischemic strokes of the cardioembolic subtype was diagnosed in the ACerA territory in the presence of an unstable atherosclerotic plaque: group 1 (CPP) 0%; group 2 (IPP) 0%; group 3 (OPP) 0.24%, n = 1; group 4 (CAP) 0.18%, n = 1; group 5 (IAP) 1.96%, n = 1; group 6 (OAP) 5.1%, n = 2; p 0.9999. The probable cause was embolization against the background increase in the arterial pressure before ICA clamping. In turn, the majority of ischemic strokes of the hemodynamic subtype developed in the territory of PCerA: group 1 (CPP) 0%; group 2 (IPP) 1.73%, n = 3; group 3 (OPP) 3.8%, n = 2; group 4 (CAP) 0.18%, n = 1; group 5 (IAP) 0%; group 6 (OAP) 2.56%, n = 1; p 0.9999. This pattern coincided with the largest number of patients with CW of the IPP and OPP types among all open variants of the structure. CONCLUSION: Parameters of retrograde pressure in the ICA and intraoperative cerebral oximetry do not always demonstrate the need for a temporary shunt (TS). Due to the opened structure of CW, the redistribution of blood flow occurs with the formation of zones of hypo- and hyperperfusion, causing ischemic alterations in the brain matter. Thus, in order to maintain adequate cerebral hemodynamics, to mitigate the effect of hypo- and hyperperfusion, and reduce the risk of ischemic stroke, the open variant of the CW structure should be considered as an indication for a TS.

Konkurencja wewnątrzorganizacyjna w grupach Kapitałowych

Business groups as one of the forms of capital concentration began to appear in developed economies from the end of the 19th century as a result of geographical expansion, diversification and the development of enterprises stimulated by industrialization. Currently, they take a significant part of the value added in the economy. In the context of institutional regulation of transactions, business groups are considered to be an intermediate structure between a pure market and a pure hierarchy. The subsidiaries within a business group enter into various interactions, partly based on market principles, and partly regulated by hierarchical coordination mechanisms. Although the main goal of this structure is cooperation of subsidiaries, in their functioning one can see the formation of relations characterized by competition. The aim of the article is to identify the perception of competition processes within business groups. It is a relatively unexplored issue, studied mainly on the example of international corporations, but of great importance for the effectiveness of the entire business group. The research was based on a sample of 121 parent companies listed on the Warsaw Stock Exchange. The results of the research show that subsidiaries within a business group display competitive behavior towards their sister entities, although of low intensity. The tendency towards the prevalence of the resource competition (on the internal market) over the product and market competition (on the external market) is also visible. The research findings confirmed the existing conceptual analyses and enabled an in-depth characterization of competitive processes in business groups from the perspective of the entire group, taking into account the intensity and areas of competitive behavior.

Structure of boehmite-derived γ-alumina and its transformation mechanism revealed by electron crystallography

γ-Alumina is a used material, while its precise crystal structure and transformation mechanism derived from boehmite have remained unclear in the literature for decades. In this work, quantitative electron microscopy has been applied to study the crystalline structure of γ-alumina and its transformation mechanism from boehmite. Based on Rietveld refinement of electron diffraction patterns, a new tetragonal structure model, with a space group of I41/amd (No. 141), was proposed for the γ-alumina phase, with Al cations on 4a, 8c, 8d and 16g sites and O anions on the 16h site, which could provide better fits than current models. During the boehmite to γ-alumina transformation induced by e-beam irradiation, when the boehmite layers were oriented along the edge-on direction, a shrinkage caused by dehydration was directly observed. Two kinds of boehmite to γ-alumina transformation mechanisms, namely collapse and reaction mechanisms, were elucidated crystallographically in detail with new insights through an intermediate structure, and the reaction mechanism was demonstrated to produce much reduced changes in dimensions and volume, compared with the collapse mechanism. The experimental observations supported the reaction mechanism, which occurred through partial occupation of the dehydrated space by diffusion in the initial stage of the transformation, without the formation of voids that only appeared after the initial stage. Filling tetrahedral interstices of the intermediate structure with Al cations in different ways yields tetragonal or cubic γ-alumina structures, and the tetragonal structure is energetically favorable because of smaller lattice distortions required, compared with the cubic structure. The crystallographic orientation relationships of γ-alumina with the parent boehmite phase deduced from the proposed mechanisms are consistent with the experimental observations.

Uniformity on generalized topological spaces

PurposeThe present article deals with the initiation and study of a uniformity like notion, captioned μ-uniformity, in the context of a generalized topological space.Design/methodology/approachThe existence of uniformity for a completely regular topological space is well-known, and the interrelation of this structure with a proximity is also well-studied. Using this idea, a structure on generalized topological space has been developed, to establish the same type of compatibility in the corresponding frameworks.FindingsIt is proved, among other things, that a μ-uniformity on a non-empty set X always induces a generalized topology on X, which is μ-completely regular too. In the last theorem of the paper, the authors develop a relation between μ-proximity and μ-uniformity by showing that every μ-uniformity generates a μ-proximity, both giving the same generalized topology on the underlying set.Originality/valueIt is an original work influenced by the previous works that have been done on generalized topological spaces. A kind of generalization has been done in this article, that has produced an intermediate structure to the already known generalized topological spaces.

Formation Process of Long-Period Stacking-Ordered Structures in Mg97Zn1Y2 Alloy Comprising HCP and Cubic Phases Fabricated by High-Pressure High-Temperature Annealing

As-cast Mg97Zn1Y2 alloy consists of α-Mg matrix and 18R-type long-period stacking-ordered (LPSO) structures. We observed that the alloy undergoes a phase transformation to D03 superlattices and α-Mg matrix due to high-pressure high-temperature (HPHT) annealing at 3 GPa and above 773 K. Further, the alloy recovered after HPHT annealing, consisting of the α-Mg matrix and D03 superlattices, transformed into 18R-type LPSO structures during further annealing at ambient pressure. An fcc structure with a lattice parameter of 1.42 nm, which was twice that of D03, emerged in both the collapse process of the 18R-type LPSO structure under high-pressure, and the formation process of the 18R-type LPSO structure at ambient pressure. This fcc phase was an intermediate structure between 18R-type LPSO and D03. From the electron diffraction results, it is considered that 18R-type LPSO is continuously present with 2H including stacking faults, which almost corresponded with previous studies.

HTN RESUME 2 Akhyar164

Dapat dikatakan bahwa partai politik itu merupakan salah satu bentuk organisasi politik di luar struktur negara dan mempunyai posisi sebagai struktur antara (intermediate-structure) di antara suprastruktur pemerintahan negara dengan infrastruktur kehidupan bersama dalam masyarakat.