Assessment of cognitive and psychiatric disturbances in people with post-COVID-19 condition: a cross-sectional observational study.

Objective: Cognitive and psychiatric symptoms have been increasingly reported after severe acute respiratory syndrome coronavirus 2 infection, developing soon after infection and possibly persisting for several months. We aimed to study this syndrome and start implementing strategies for its assessment.

Methods: Consecutive patients, referred by the infectious disease specialist because of cognitive complaints after COVID-19, were neurologically evaluated.

TERRA expression is regulated by the telomere-binding proteins POT-1 and POT-2 in Caenorhabditis elegans.

Several aspects of telomere biology are regulated by the telomeric repeat-containing RNA TERRA. While TERRA expression is conserved through evolution, species-specific mechanisms regulate its biogenesis and function. Here we report on the expression of TERRA in Caenorhabditis elegans.

Recent innovations in non-invasive brain stimulation (NIBS) for the treatment of unipolar and bipolar depression: a narrative review.

Depression, either bipolar or unipolar, is a highly prevalent and disabling condition. Even though several treatment options exist for depressed patients, a significant portion of individuals receiving conventional pharmacotherapy fails to achieve and sustain remission. For this reason, there is a strong need for effective alternatives to pharmacotherapy.

A Hierarchical Model To Understand the Processing of Polysaccharides/Protein-Based Films in Ionic Liquids.

In recent years, biomaterials from abundant and renewable sources have shown potential in medicine and materials science alike. In this study, we combine theoretical modeling, molecular dynamics simulations, and several experimental techniques to understand the regeneration of cellulose/silk-, chitin/silk-, and chitosan/silk-based biocomposites after dissolution in ionic liquid and regeneration in water. We propose a novel theoretical model that correlates the composite's microscopic structure to its bulk properties.

Computational and experimental analysis of short peptide motifs for enzyme inhibition.

The metabolism of living systems involves many enzymes that play key roles as catalysts and are essential to biological function. Searching ligands with the ability to modulate enzyme activities is central to diagnosis and therapeutics. Peptides represent a promising class of potential enzyme modulators due to the large chemical diversity, and well-established methods for library synthesis.

Impact of Phosphorylation and Pseudophosphorylation on the Early Stages of Aggregation of the Microtubule-Associated Protein Tau.

The microtubule-associated protein tau regulates the stability of microtubules within neurons in the central nervous system. In turn, microtubules are responsible for the remodeling of the cytoskeleton that ultimately leads to the formation or pruning of new connections among neurons. As a consequence, dysfunction of tau is associated with many forms of dementia as well as Alzheimer's disease.

Tau assembly: the dominant role of PHF6 (VQIVYK) in microtubule binding region repeat R3.

Self-aggregation of the microtubule-binding protein Tau reduces its functionality and is tightly associated with Tau-related diseases, termed tauopathies. Tau aggregation is also strongly associated with two nucleating six-residue segments, namely PHF6 (VQIVYK) and PHF6* (VQIINK). In this paper, using experiments and computational modeling, we study the self-assembly of individual and binary mixtures of Tau fragments containing PHF6* (R2/wt; (273)GKVQIINKKLDL(284)) and PHF6 (R3/wt; (306)VQIVYKPVDLSK(317)) and a mutant R2/ΔK280 associated with a neurodegenerative tauopathy.

Regulation and aggregation of intrinsically disordered peptides.

Intrinsically disordered proteins (IDPs) are a unique class of proteins that have no stable native structure, a feature that allows them to adopt a wide variety of extended and compact conformations that facilitate a large number of vital physiological functions. One of the most well-known IDPs is the microtubule-associated tau protein, which regulates microtubule growth in the nervous system. However, dysfunctions in tau can lead to tau oligomerization, fibril formation, and neurodegenerative disease, including Alzheimer's disease.

Double resolution model for studying TMAO/water effective interactions.

The structural properties of water molecules surrounding TMAO molecules are studied using a newly developed atomistic force field for TMAO, combined with a multiscale coarse-graining (MS-CG) force field derived from the atomistic simulations. The all-atom force field is parametrized to work with the OPLS force field and with SPC, TIP3P, and TIP4P water models. The dual-resolution modeling enables a complete study of the dynamical and structural properties of the system, with the CG model providing important new physical insights into which interactions are critical in determining the structure of water around TMAO.

Role of β-hairpin formation in aggregation: the self-assembly of the amyloid-β(25-35) peptide.

The amyloid-β(25-35) peptide plays a key role in the etiology of Alzheimer's disease due to its extreme toxicity even in the absence of aging. Because of its high tendency to aggregate and its low solubility in water, the structure of this peptide is still unknown. In this work, we sought to understand the early stages of aggregation of the amyloid-β(25-35) peptide by conducting simulations of oligomers ranging from monomers to tetramers.

Coarse-grained modeling of simple molecules at different resolutions in the absence of good sampling.

Many problems of interest in modern science originate from the complex network of interactions of different molecular structures, each possessing its own typical length and time scale of relevance. In such materials, nontrivial properties emerge from the different length and time scales involved that could not be predicted from the properties of each individual subunit taken alone. A solution to the formidable theoretical and computational issues raised by these systems involves coarse-graining, a procedure in which multiple atoms are grouped into a few interaction sites.

A generalized mean field theory of coarse-graining.

A general mean field theory is presented for the construction of equilibrium coarse-grained models. Inverse methods that reconstruct microscopic models from low resolution experimental data can be derived as particular implementations of this theory. The theory also applies to the opposite problem of reduction, where relevant information is extracted from available equilibrium ensemble data.

The multiscale coarse-graining method. VI. Implementation of three-body coarse-grained potentials.

Many methodologies have been proposed to build reliable and computationally fast coarse-grained potentials. Typically, these force fields rely on the assumption that the relevant properties of the system under examination can be reproduced using a pairwise decomposition of the effective coarse-grained forces. In this work it is shown that an extension of the multiscale coarse-graining technique can be employed to parameterize a certain class of two-body and three-body force fields from atomistic configurations.

Langevin stabilization of molecular-dynamics simulations of polymers by means of quasisymplectic algorithms.

Algorithms for the numerical integration of Langevin equations are compared in detail from the point of view of their accuracy, numerical efficiency, and stability to assess them as potential candidates for molecular-dynamics simulations of polymeric systems. Some algorithms are symplectic in the deterministic frictionless limit and prove to stabilize long time-step integrators. They are tested against other popular algorithms.

A manifestation of the Ostwald step rule: molecular-dynamics simulations and free-energy landscape of the primary nucleation and melting of single-molecule polyethylene in dilute solution.

The paper presents numerical results from extensive molecular-dynamics simulations of the crystallization process of a single polyethylene chain with N=500 monomers. The development of the ordered structure is seen to proceed along different routes involving either the global reorganization of the chain or, alternatively, well-separated connected nuclei. No dependence on the thermal history was observed at the late stages of the crystallization.

New spectrophotometric method for the determination of phenothiazine derivatives.

The use of a reduced solution of phosphomolybdic acid for the precipitation of phenothiazine derivatives offers excellent conditions for the assay of these compounds. The quantitative assay range for each of the phenothiazine derivatives was determined by the precipitation, proportionality, in accordance with the procedure used for chlorpromazine. The conditions offered by the new method make it possible to assay 12 phenothiazine derivatives.