The formation and architecture of surface-initiated polymer brush gene delivery complexes.

Understanding the architecture and mechanism of assembly of polyelectrolyte-nucleic acid complexes is critical to the rational design of their performance for gene delivery. Surface-initiated polymer brushes were recently found to be particularly effective at delivering oligonucleotides and maintaining high knock down efficiencies for prolonged periods of time, in highly proliferative cells. However, what distinguishes their binding capacity for oligonucleotides from that of larger therapeutic macromolecules remains unknown.

Monitoring of Isothermal Crystallization and Time-Temperature Transformation of Amorphous Felodipine: The Time-Domain Nuclear Magnetic Resonance Method.

The isothermal crystallization process of felodipine has been investigated using the time-domain Nuclear Magnetic Resonance (NMR) method for amorphous bulk and ground samples. The obtained induction and crystallization times were then used to construct the time-temperature-transformation (TTT) diagram, both above and below the glass transition temperature (T). The Nose temperature was found equal to 363 K.

(CaMn)MnTeO - An Anomalously Stable High-Pressure Double Perovskite.

High pressure high temperature treatments of the composition CaMnMnTeO are found to yield only an ABB'O-type double perovskite (CaMn)MnTeO, rather than a AA'BB'O double double perovskite with A- and B- site cation order as found in analogs CaMnMnReO and CaMnMnWO with similar cation sizes. Double perovskite (CaMn)MnTeO adopts a monoclinic structure in space group P2/n with a framework of highly tilted MnO and TeO octahedra enclosing disordered Ca and Mn cations. Magnetic measurements show that (CaMn)MnTeO is a highly frustrated spin glass with a freezing transition at 5 K, and no long-range spin order is apparent by neutron diffraction at 1.

Investigation of the Dynamic Behaviour of H and D in a Kinetic Quantum Sieving System.

Porous organic cages (POCs) are nanoporous materials composed of discrete molecular units that have uniformly distributed functional pores. The intrinsic porosity of these structures can be tuned accurately at the nanoscale by altering the size of the porous molecules, particularly to an optimal size of 3.6 Å, to harness the kinetic quantum sieving effect.

Terbium-149 production: a focus on yield and quality improvement towards preclinical application.

Terbium-149 (T = 4.1 h, E = 3.98 MeV (16.

Combination of a pH-responsive peptide amphiphile and a conventional antibiotic in treating Gram-negative bacteria.

Background: Clinical treatments ofgastric infections using antibiotics suffer from the undesired killing of commensal bacteria and emergence of antibiotic resistance. It is desirable to develop pH-responsive antimicrobial peptides (AMPs) that kill pathogenic bacteria such as H. pyloriand resistant E.

Human cystatin C induces the disaggregation process of selected amyloid beta peptides: a structural and kinetic view.

Neurodegenerative diseases, such as Alzheimer's disease (AD) and various types of amyloidosis, are incurable; therefore, understanding the mechanisms of amyloid decomposition is crucial to develop an effective drug against them for future therapies. It has been reported that one out of three people over the age of 85 are suffering from dementia as a comorbidity to AD. Amyloid beta (Aβ), the hallmark of AD, transforms structurally from monomers into β-stranded aggregates (fibrils) via multiple oligomeric states.

Soft Phonon Mode Triggering Fast Ag Diffusion in Superionic Argyrodite Ag GeSe.

The structural coexistence of dual rigid and mobile sublattices in superionic Argyrodites yields ultralow lattice thermal conductivity along with decent electrical and ionic conductivities and therefore attracts intense interest for batteries, fuel cells, and thermoelectric applications. However, a comprehensive understanding of their underlying lattice and diffusive dynamics in terms of the interplay between phonons and mobile ions is missing. Herein, inelastic neutron scattering is employed to unravel that phonon softening on heating to T ≈ 350 K triggers fast Ag diffusion in the canonical superionic Argyrodite Ag GeSe .

Characterization of Tunneled Wide Band Gap Mixed Conductors: The NaO-GaO-TiO System.

This article focuses on the NaO-GaO-TiO system, which is barely explored in the study of transparent conductive oxides (TCOs). NaGaTiO (n = 5, 6, and 7 and x ≈ 0.7-0.

Molecular Dynamics Simulations of Selected Amorphous Stilbenoids and Their Amorphous Solid Dispersions with Poly(Vinylpyrrolidone).

Amorphous solid dispersions (ASDs) are one of the promising strategies to improve the solubility and dissolution rate of poorly soluble compounds. In this study, Molecular Dynamics simulations were used to investigate the interactions between three selected stilbenoids with important biological activity (resveratrol, pinostilbene and pterostilbene) and poly(vinylpyrrolidone). The analysis of the pair distribution functions and hydrogen bond distributions reveals a significant weakening of the hydrogen bond network of the stilbenoids in ASDs compared to the pure (no polymer) amorphous systems.

Probing the mutational landscape of the SARS-CoV-2 spike protein via quantum mechanical modeling of crystallographic structures.

We employ a recently developed complexity-reduction quantum mechanical (QM-CR) approach, based on complexity reduction of density functional theory calculations, to characterize the interactions of the SARS-CoV-2 spike receptor binding domain (RBD) with ACE2 host receptors and antibodies. QM-CR operates via ab initio identification of individual amino acid residue's contributions to chemical binding and leads to the identification of the impact of point mutations. Here, we especially focus on the E484K mutation of the viral spike protein.

Small-angle x-ray and neutron scattering of MexR and its complex with DNA supports a conformational selection binding model.

In this work, we used small-angle x-ray and neutron scattering to reveal the shape of the protein-DNA complex of the Pseudomonas aeruginosa transcriptional regulator MexR, a member of the multiple antibiotics resistance regulator (MarR) family, when bound to one of its native DNA binding sites. Several MarR-like proteins, including MexR, repress the expression of efflux pump proteins by binding to DNA on regulatory sites overlapping with promoter regions. When expressed, efflux proteins self-assemble to form multiprotein complexes and actively expel highly toxic compounds out of the host organism.

Hands-on training in structural biology, a tool for sustainable development in Africa series 4.

Structural biology is an essential tool for understanding the molecular basis of diseases, which can guide the rational design of new drugs, vaccines, and the optimisation of existing medicines. However, most African countries do not conduct structural biology research due to limited resources, lack of trained persons, and an exodus of skilled scientists. The most urgent requirement is to build on the emerging centres in Africa - some well-established, others growing.

Topological Dynamics of Micelles Formed by Geometrically Varied Surfactants.

The molecular architecture of sugar-based surfactants strongly affects their self-assembled structure, i.e., the type of micelles they form, which in turn controls both the dynamics and rheological properties of the system.

Unveiling the S=3/2 Kitaev honeycomb spin liquids.

The S=3/2 Kitaev honeycomb model (KHM) is a quantum spin liquid (QSL) state coupled to a static Z gauge field. Employing an SO(6) Majorana representation of spin3/2's, we find an exact representation of the conserved plaquette fluxes in terms of static Z gauge fields akin to the S=1/2 KHM which enables us to treat the remaining interacting matter fermion sector in a parton mean-field theory. We uncover a ground-state phase diagram consisting of gapped and gapless QSLs.

Strong synergistic interactions in zwitterionic-anionic surfactant mixtures at the air-water interface and in micelles: The role of steric and electrostatic interactions.

Hypothesis: The milder interaction with biosystems makes the zwitterionic surfactants an important class of surfactants, and they are widely used in biological applications and in personal care formulations. An important aspect of those applications is their strong synergistic interaction with anionic surfactants. It is anticipated that the strong interaction will significantly affect the adsorption and self-assembly properties.

The impact of folding modes and deuteration on the atomic resolution structure of hen egg-white lysozyme.

The biological function of a protein is intimately related to its structure and dynamics, which in turn are determined by the way in which it has been folded. In vitro refolding is commonly used for the recovery of recombinant proteins that are expressed in the form of inclusion bodies and is of central interest in terms of the folding pathways that occur in vivo. Here, biophysical data are reported for in vitro-refolded hydrogenated hen egg-white lysozyme, in combination with atomic resolution X-ray diffraction analyses, which allowed detailed comparisons with native hydrogenated and refolded perdeuterated lysozyme.

Π-GISANS: probing lateral structures with a fan shaped beam.

We have performed grazing incidence neutron small angle scattering using a fan shaped incident beam focused along one dimension. This allows significantly reduced counting times for measurements of lateral correlations parallel to an interface or in a thin film where limited depth resolution is required. We resolve the structure factor of iron inclusions in aluminium oxide and show that the ordering of silica particles deposited on a silicon substrate depends on their size.

Polarized neutron scattering studies of magnetic excitations in iron-selenide superconductor LiFeODFeSe (41 K).

We report polarized neutron scattering measurements of the low energy spin fluctuations of the iron-selenide superconductor LiFeODFeSe below and above its superconducting transition temperature= 41 K. Our experiments confirmed that the resonance mode near 21 meV is magnetic. Moreover, the spin excitations are essentially isotropic in spin space at 5 ⩽⩽ 29 meV in the superconducting and normal states.

Structural Disruptions of the Outer Membranes of Gram-Negative Bacteria by Rationally Designed Amphiphilic Antimicrobial Peptides.

Gram-negative bacteria are covered by both an inner cytoplasmic membrane (IM) and an outer membrane (OM). Antimicrobial peptides (AMPs) must first permeate through the OM and cell wall before attacking the IM to cause cytoplasmic leakage and kill the bacteria. The bacterial OM is an asymmetric bilayer with the outer leaflet primarily composed of lipopolysaccharides (LPSs) and the inner leaflet composed of phospholipids (PLs).

How do Self-Assembling Antimicrobial Lipopeptides Kill Bacteria?

Antimicrobial peptides are promising alternatives to traditional antibiotics. A group of self-assembling lipopeptides was formed by attaching an acyl chain to the N-terminus of α-helix-forming peptides with the sequence C-G(IIKK)I-NH (CG, = 4-12 and = 2). CG self-assemble into nanofibers above their critical aggregation concentrations (CACs).

Atomic, electronic and magnetic structure of an oxygen interstitial in neutron-irradiated AlO single crystals.

A single radiation-induced superoxide ion [Formula: see text] has been observed for the first time in metal oxides. This structural defect has been revealed in fast-neutron-irradiated (6.9×10 n/cm) corundum (α-AlO) single crystals using the EPR method.

Arrangement of Ceramides in the Skin: Sphingosine Chains Localize at a Single Position in Stratum Corneum Lipid Matrix Models.

Understanding the structure of the stratum corneum (SC) is essential to understand the skin barrier process. The long periodicity phase (LPP) is a unique trilayer lamellar structure located in the SC. Adjustments in the composition of the lipid matrix, as in many skin abnormalities, can have severe effects on the lipid organization and barrier function.

Establishment of a clinical SPECT/CT protocol for imaging of Tb.

Background: It has been proposed, and preclinically demonstrated, that Tb is a better alternative to Lu for the treatment of small prostate cancer lesions due to its high emission of low-energy electrons. Tb also emits photons suitable for single-photon emission computed tomography (SPECT) imaging. This study aims to establish a SPECT protocol for Tb imaging in the clinic.