Cationic Ring-Opening Polymerization-Induced Self-Assembly (CROPISA) of 2-Oxazolines: From Block Copolymers to One-Step Gradient Copolymer Nanoparticles.

In recent years, polymerization-induced self-assembly (PISA) has emerged as a powerful method for the straightforward synthesis of polymer nanoparticles at high concentration. In this study, we describe for the first time the synthesis of poly(2-oxazoline) nanoparticles by dispersion cationic ring-opening polymerization-induced self-assembly (CROPISA) in n-dodecane. Specifically, a n-dodecane-soluble aliphatic poly(2-(3-ethylheptyl)-2-oxazoline) (PEHOx) block was chain-extended with poly(2-phenyl-2-oxazoline) (PPhOx).

Single-Step Synthesis of Highly Sensitive F MRI Tracers by Gradient Copolymerization-Induced Self-Assembly.

Amphiphilic gradient copolymers are promising alternatives to block copolymers for self-assembled nanomaterials due to their straightforward synthesis via statistical copolymerization of monomers with different reactivities and hydrophilicity. By carefully selecting monomers, nanoparticles can be synthesized in a single step through gradient copolymerization-induced self-assembly (gPISA). We synthesized highly sensitive F MRI nanotracers via aqueous dispersion gPISA of hydrophilic poly(ethylene glycol) methyl ether methacrylate (PEGMA) with core-forming ,-(2,2,2-trifluoroethyl)acrylamide (TFEAM).

Ionisation of atoms determined by kappa refinement against 3D electron diffraction data.

Conventional refinement strategies used for three-dimensional electron diffraction (3D ED) data disregard the bonding effects between the atoms in a molecule by assuming a pure spherical model called the Independent Atom model (IAM) and may lead to an inaccurate or biased structure. Here we show that it is possible to perform a refinement going beyond the IAM with electron diffraction data. We perform kappa refinement which models charge transfers between atoms while assuming a spherical model.

Cationic fluorinated micelles for cell labeling and F-MR imaging.

Magnetic resonance imaging (MRI) relies on appropriate contrast agents, especially for visualizing transplanted cells within host tissue. In recent years, compounds containing fluorine-19 have gained significant attention as MRI probe, particularly in dual H/F-MR imaging. However, various factors affecting probe sensitivity, such as fluorine content and the equivalency of fluorine atoms, must be considered.

Stimuli-Responsive Polymers at the Interface with Biology.

There has been growing interest in polymeric systems that break down or undergo property changes in response to stimuli. Such polymers can play important roles in biological systems, where they can be used to control the release of therapeutics, modulate imaging signals, actuate movement, or direct the growth of cells. In this Perspective, after discussing the most important stimuli relevant to biological applications, we will present a selection of recent exciting developments.

Stimuli-Responsive Polymers for Advanced F Magnetic Resonance Imaging: From Chemical Design to Biomedical Applications.

Fluorine magnetic resonance imaging (F MRI) is a rapidly evolving research area with a high potential to advance the field of clinical diagnostics. In this review, we provide an overview of the recent progress in the field of fluorinated stimuli-responsive polymers applied as F MRI tracers. These polymers respond to internal or external stimuli (e.

Long-term dissolution of thermo- and pH-responsive, F magnetic resonance-traceable and injectable polymer implants.

F magnetic resonance (F MR) tracers stand out for their wide range of applications in experimental and clinical medicine, as they can be precisely located in living tissues with negligible fluorine background. This contribution demonstrates the long-term dissolution of multiresponsive fluorinated implants designed for prolonged release. Implants were detected for 14 (intramuscular injection) and 20 (subcutaneous injection) months by F MR at 4.

Highly Effective Synthetic Polymer-Based Blockers of Non-Specific Interactions in Immunochemical Analyses.

In vitro diagnostic methods face non-specific interactions increasing their background level and influencing the efficacy and reproducibility. Currently, the most important and employed blocker of non-specific interactions is bovine serum albumin (BSA), an animal product with some disadvantages like its batch-to-batch variability and contamination with RNases. Herein, we developed amphiphilic water-soluble synthetic copolymers based on the highly biocompatible, non-immunogenic and nontoxic -2-(hydroxypropyl)methacrylamide (HPMA)-based copolymers or poly(oxazoline)s as highly effective synthetic blockers of non-specific interactions and an effective BSA alternative.

Multifunctional Poly(2-ethyl-2-oxazoline) Copolymers Containing Dithiolane and Pentafluorophenyl Esters as Effective Reactive Linkers for Gold Surface Coatings.

Surface functionalization with biological macromolecules is an important task for the development of sensor materials, whereby the interaction with other biological materials should be suppressed. In this work, we developed a novel multifunctional poly(2-ethyl-2-oxazoline)-dithiolane conjugate as a versatile linker for gold surface immobilization of amine-containing biomolecules, containing poly(2-ethyl-2-oxazoline) as antifouling polymer, dithiolane for surface immobilization, and activated esters for protein conjugation. First, a well-defined carboxylic acid containing copoly(2-ethyl-2-oxazoline) was synthesized by cationic ring-opening copolymerization of 2-ethyl-2-oxazoline with a methyl ester-containing 2-oxazoline monomer, followed by postpolymerization modifications.

Antifouling Properties of Poly(2-Oxazoline)s and Poly(2-Oxazine)s: Direct Comparison of Polymer-Coated Surfaces with the Same Coating Parameters.

This study presents a systematic comparison of the antifouling properties of water-soluble poly(2-oxazoline) (PAOx) and poly(2-oxazine) (PAOzi) brushes grafted to gold surfaces. PAOx and PAOzi are emerging polymer classes in biomedical sciences and are being considered superior alternatives to widely used polyethylene glycol (PEG). Four different polymers, poly(2-methyl-2-oxazoline) (PMeOx), poly(2-ethyl-2-oxazoline) (PEtOx), poly(2-methyl-2-oxazine) (PMeOzi), and poly(2-ethyl-2-oxazine) (PEtOzi), each of them in three different chain lengths, are synthesized and characterized for their antifouling properties.

Gut microbiota variation between climatic zones and due to migration strategy in passerine birds.

Introduction: Decreasing biotic diversity with increasing latitude is an almost universal macroecological pattern documented for a broad range of taxa, however, there have been few studies focused on changes in gut microbiota (GM) across climatic zones.

Methods: Using 16S rRNA amplicon profiling, we analyzed GM variation between temperate (Czechia) and tropical (Cameroon) populations of 99 passerine bird species and assessed GM similarity of temperate species migrating to tropical regions with that of residents/short-distance migrants and tropical residents. Our study also considered the possible influence of diet on GM.

Conformational Parameters and Hydrodynamic Behavior of Poly(2-Methyl-2-Oxazoline) in a Broad Molar Mass Range.

In this work, we report our results on the hydrodynamic behavior of poly(2-methyl-2-oxazoline) (PMeOx). PMeOx is gaining significant attention for use as hydrophilic polymer in pharmaceutical carriers as an alternative for the commonly used poly(ethylene glycol) (PEG), for which antibodies are found in a significant fraction of the human population. The main focus of the current study is to determine the hydrodynamic characteristics of PMeOx under physiological conditions, which serves as basis for better understanding of the use of PMeOx in pharmaceutical applications.

Thirteen moth species (Lepidoptera, Erebidae, Noctuidae) newly recorded in South Africa, with comments on their distribution.

Background: Thanks to the high diversity of ecosystems and habitats, South Africa harbours tremendous diversity of insects. The Kruger National Park, due to its position close to the border between two biogeographic regions and high heterogeneity of environmental conditions, represents an insufficiently studied hotspot of lepidopteran diversity. During our ecological research in the Kruger National Park, we collected abundant moth material, including several interesting faunistic records reported in this study.

Synthesis of F MRI Nanotracers by Dispersion Polymerization-Induced Self-Assembly of -(2,2,2-Trifluoroethyl)acrylamide in Water.

F magnetic resonance imaging (MRI) using fluoropolymer tracers has recently emerged as a promising, non-invasive diagnostic tool in modern medicine. However, despite its potential, F MRI remains overlooked and underused due to the limited availability or unfavorable properties of fluorinated tracers. Herein, we report a straightforward synthetic route to highly fluorinated F MRI nanotracers aqueous dispersion polymerization-induced self-assembly of a water-soluble fluorinated monomer.

Moth Diversity Increases along a Continent-Wide Gradient of Environmental Productivity in South African Savannahs.

Environmental productivity, i.e., the amount of biomass produced by primary producers, belongs among the key factors for the biodiversity patterns.

Latitudinal but not elevational variation in blood glucose level is linked to life history across passerine birds.

Macrophysiological research is vital to our understanding of mechanisms underpinning global life history variation and adaptation to diverse environments. Here, we examined latitudinal and elevational variation in a key substrate of energy metabolism and an emerging physiological component of pace-of-life syndromes, blood glucose concentration. Our data, collected from 61 European temperate and 99 Afrotropical passerine species, revealed that baseline blood glucose increases with both latitude and elevation, whereas blood glucose stress response shows divergent directions, being stronger at low latitudes and high elevations.

Feather growth and quality across passerines is explained by breeding rather than moulting latitude.

Tropical bird species are characterized by a comparatively slow pace of life, being predictably different from their temperate zone counterparts in their investments in growth, survival and reproduction. In birds, the development of functional plumage is often considered energetically demanding investment, with consequences on individual fitness and survival. However, current knowledge of interspecific variation in feather growth patterns is mostly based on species of the northern temperate zone.

Influence of Chain Length of Gradient and Block Copoly(2-oxazoline)s on Self-Assembly and Drug Encapsulation.

Amphiphilic gradient copolymers represent a promising alternative to extensively used block copolymers due to their facile one-step synthesis by statistical copolymerization of monomers of different reactivity. Herein, an in-depth analysis is provided of micelles based on amphiphilic gradient poly(2-oxazoline)s with different chain lengths to evaluate their potential for micellar drug delivery systems and compare them to the analogous diblock copolymer micelles. Size, morphology, and stability of self-assembled nanoparticles, loading of hydrophobic drug curcumin, as well as cytotoxicities of the prepared nanoformulations are examined using copoly(2-oxazoline)s with varying chain lengths and comonomer ratios.

Fluorine-Containing Block and Gradient Copoly(2-oxazoline)s Based on 2-(3,3,3-Trifluoropropyl)-2-oxazoline: A Quest for the Optimal Self-Assembled Structure for F Imaging.

The use of fluorinated contrast agents in magnetic resonance imaging (MRI) facilitates improved image quality due to the negligible amount of endogenous fluorine atoms in the body. In this work, we present a comprehensive study of the influence of the amphiphilic polymer structure and composition on its applicability as contrast agents in F MRI. Three series of novel fluorine-containing poly(2-oxazoline) copolymers and terpolymers, hydrophilic-fluorophilic, hydrophilic-lipophilic-fluorophilic, and hydrophilic-thermoresponsive-fluorophilic, with block and gradient distributions of the fluorinated units, were synthesized.

A broad tuneable birdcage coil for mouse H/F MR applications.

In this paper, we present the design and implementation of a H/F volume coil for mouse body magnetic resonance (MR) imaging and spectroscopy using a high magnetic field (4.7 T). By changing the geometry of the coil rungs to include both nuclei for MR experiments, this innovative coil can be tuned over an extremely wide range of frequency.

Antifouling fluoropolymer-coated nanomaterials for F MRI.

We developed a multifunctional polymer coating for nanoparticles (NPs) that enables simultaneous detection by 19F MRI and shielding from blood plasma fouling. The coating is based on a water-soluble fluorinated poly(N-(2-fluoroethyl)acrylamide) (PFEAM) that shows high 19F MRI sensitivity, cytocompatibility and excellent antifouling properties, significantly outperforming polyethylene glycol. A proof-of-concept experiment was performed by synthesizing polymer-coated gold NPs that were successfully visualized by 19F MRI at magnetic fields close to the fields used in clinical practice.

New records of six moth (Lepidoptera: Erebidae, Lasiocampidae) species in south African countries, with comments on their distribution.

Background: Southern Africa hosts a high diversity of ecosystems and habitats with a tremendous diversity of Lepidoptera. Although it is one of the most studied parts of the Afrotropics, the knowledge on diversity and distribution of south African moth fauna remains insufficient. To partly fill this gap, we surveyed macromoths by automatic light traps in five localities in two relatively less sampled south African countries.