A Broad Search for Counterrotating Gas and Stars: Evidence for Mergers and Accretion

We measure the frequency of bulk gas-stellar counterrotation in a sample of 67 galaxies drawn from the Nearby Field Galaxy Survey, a broadly representative survey of the local galaxy population down to M_B-15. We detect 4 counterrotators among 17 E/S0's with extended gas emission (24% +8 -6). In contrast, we find no clear examples of bulk counterrotation among 38 Sa-Sbc spirals, although one Sa does show peculiar gas kinematics. This result implies that, at 95% confidence, no more than 8% of Sa-Sbc spirals are bulk counterrotators. Among types Sc and later, we identify only one possible counterrotator, a Magellanic irregular. We use these results together with the physical properties of the counterrotators to constrain possible origins for this phenomenon.Comment: 19 pages, 4 figures, AJ, accepte

Decoration of nanovesicles with pH (low) insertion peptide (pHLIP) for targeted delivery

Acidity at surface of cancer cells is a hallmark of tumor microenvironments, which does not depend on tumor perfusion, thus it may serve as a general biomarker for targeting tumor cells. We used the pH (low) insertion peptide (pHLIP) for decoration of liposomes and niosomes. pHLIP senses pH at the surface of cancer cells and inserts into the membrane of targeted cells, and brings nanomaterial to close proximity of cellular membrane. DMPC liposomes and Tween 20 or Span 20 niosomes with and without pHLIP in their coating were fully characterized in order to obtain fundamental understanding on nanocarrier features and facilitate the rational design of acidity sensitive nanovectors. The samples stability over time and in presence of serum was demonstrated. The size, ζ-potential, and morphology of nanovectors, as well as their ability to entrap a hydrophilic probe and modulate its release were investigated. pHLIP decorated vesicles could be useful to obtain a prolonged (modified) release of biological active substances for targeting tumors and other acidic diseased tissues

Model cell membrane interaction with a bioinspired amphoteric polymer

We present recent investigation by means of nanoscale techniques on biocompatible linear polyamidoamines with amphoteric character, namely AGMA1 and ARGO7. These polymers have been shown of extremely promising and already proved medical interest, comprising their strong protection actions against virus infection, mainly papilloma and herpes and the extremely low toxicity of their DNA complexes, with respect to other used polymers such as PEI and protamine, applied in nanovector design for gene delivery. Our studies focus on the most important of these polymers, AGMA1, a prevailingly cationic 4-aminobutylguanidine-deriving PAA, whose mechanism of action is so far not fully understood. The current understanding is that its interaction with cell surfaces by means of glycosaminoglycans (HSPG) has a major role in its protective action against viruses. Yet, AGMA1 is active also against HPV-31, whose attachment does not appear to be dependent on HSPG. HPV-31, whose attachment does not appear to be dependent on HSPG. Therefore, AGMA1 binds other (as yet unidentified) receptors on the cell surface. As the known recipient is the HS carbohydrate moiety, other sugars rich membrane components have been proposed as probable AGMA1 target. Therefore, to shed a light on the mechanism of interaction of the polymer with sugar containing biologically relevant molecules, not HS, we have investigated AGMA1 in interaction with glycophyngolipids, Specifically, we studied multicomponent symmetric vesicles enriched in ganglioside GM1 built to mimic biological membrane domains, in the presence of AGMA1, At physiological pH, electrostatic effects should be the relevant interactions between GM1 and AGMA1. Taking advantage of the same mechanism we investigated the possibility of building lipid based core-shell particles to vehiculate AGMA1/siRNA complexes. Moreover, since it is probable that AGMA1 interacts with the barrier of mucus which cover the involved tissue we have extended our investigations also to mucin, constituting the biological barrier to the target tissues of the medical application of the polymers

Building a biomimetic membrane for neutron reflectivity investigation : complexity, asymmetry and contrast

The preparation and investigation of model membranes is deserving growing interest both for the physics of complex systems, and for biology. The need of simplified models should preserve mimicking the qualifying characteristics of biological membranes, and keep non-invasive and detailed description. As a main feature, biological membranes are non-homogeneous in the disposition of components, both in the lateral and in the transverse direction. We prepared asymmetric supported membranes containing GM1 ganglioside in biomimetic proportion according to different protocols. Then, we studied their internal structure by neutron reflectometry, providing few-Angstrom sensitivity in the cross direction meanwhile avoiding radiation damage. This technique can also be profitably applied to study interactions at the membrane surface. The best protocol has proven to be the Langmuir-Blodgett/Langmuir-Schaefer depositions. Notably, also the simpler and most accessible protocol of vesicle fusion was found to be suitable for straightforward and good quality deposition of compositionally asymmetric membranes

Model cell membrane interaction with a bioinspired amphoteric polymer

We present recent investigation by means of nanoscale techniques on biocompatible linear polyamidoamines with amphoteric character, namely AGMA1 and ARGO7. These polymers have been shown of extremely promising and already proved medical interest, comprising their strong protection actions against virus infection, mainly papilloma and herpes and the extremely low toxicity of their DNA complexes, with respect to other used polymers such as PEI and protamine, applied in nanovector design for gene delivery. Our studies focus on the most important of these polymers, AGMA1, a prevailingly cationic 4-aminobutylguanidine-deriving PAA, whose mechanism of action is so far not fully understood. The current understanding is that its interaction with cell surfaces by means of glycosaminoglycans (HSPG) has a major role in its protective action against viruses. Yet, AGMA1 is active also against HPV-31, whose attachment does not appear to be dependent on HSPG. HPV-31, whose attachment does not appear to be dependent on HSPG. Therefore, AGMA1 binds other (as yet unidentified) receptors on the cell surface. As the known recipient is the HS carbohydrate moiety, other sugars rich membrane components have been proposed as probable AGMA1 target. Therefore, to shed a light on the mechanism of interaction of the polymer with sugar containing biologically relevant molecules, not HS, we have investigated AGMA1 in interaction with glycophyngolipids, Specifically, we studied multicomponent symmetric vesicles enriched in ganglioside GM1 built to mimic biological membrane domains, in the presence of AGMA1, At physiological pH, electrostatic effects should be the relevant interactions between GM1 and AGMA1. Taking advantage of the same mechanism we investigated the possibility of building lipid based core-shell particles to vehiculate AGMA1/siRNA complexes. Moreover, since it is probable that AGMA1 interacts with the barrier of mucus which cover the involved tissue we have extended our investigations also to mucin, constituting the biological barrier to the target tissues of the medical application of the polymers

Interaction of mucins with bioinspired polymers and drug delivery particles

Mucins are glycoproteins with high molecular weight and an abundance of negatively charged oligosaccharide side chains, representing the main components in the mucous gels apart from water. Mucin structure consists of a flexible backbone (mainly serine and threonine residues) which serves as anchoring points for oligosaccharide side chains, and hydrophobic \u201cnaked domains\u201d enriched in cysteine residues. The latter can form inter-molecular bonds via disulphide links, promoting mucin association in solution. Therefore, mucins can establish adhesive interactions with particulates/biomacromolecules via electrostatic interactions, van der Waals forces, hydrophobic forces, hydrogen bonding, or chain entanglement. Mucosal drug delivery vehicles can either penetrate rapidly or establish prolonged contact. However, their development is of great challenge because little is still known about the interactions between mucin and other macromolecules. We are currently working on a comprehensive study of the interaction between mucin and macromolecules of interest for pharmaceutical developments by complementary techniques. To this scope, we employ biocompatible natural and synthetic polymers with different physical-chemical characteristics. Among them, linear polyamidoamines with amphoteric character are particularly interesting for their cyto-biocompatibility. It is indeed crucial to characterise such interactions not only in the bulk but also at the interface, since complexation between mucins and biomacromolecules takes place close to the cell membrane surface. Moreover, the strategy to overcome mucus barrier and achieve long retention time in the cell surface is to develop nano-agents which can effectively penetrate the mucus layer and accumulate at the epithelial surface. In this framework we present preliminary investigations in the bulk by small angle x-ray scattering (SAXS) and at the solid-liquid interface by employing quartz crystal microbalance (QCM-D)

The development of an operational system for estimating irrigation water use reveals socio-political dynamics in Ukraine

Irrigation is the main driver of crop production in many agricultural regions across the world. The estimation of irrigation water has the potential to enhance our comprehension of the Earth system, thus providing crucial data for food production. In this study, we have created a unique operational system for estimating irrigation water using data from satellite soil moisture, reanalysis precipitation, and potential evaporation. As a proof of concept, we implemented the method at a high resolution (1 km) during the period of 2015–2023 over the area south of the Kakhovka Dam in Ukraine, which collapsed on 6 June 2023. The selected study area enabled us to showcase that our operational system is able to track the effect of the pandemic and conflict on the irrigation water supply. Significant decreases of 63 % and 44 % in irrigation water compared to the mean irrigation water between 2015 and 2023 have been identified as being linked to the collapse of the dam and, potentially, to the COVID-19 pandemic, respectively.</p

Pathogenic A&#946; A2V versus protective A&#946; A2T mutation : early stage aggregation and membrane interaction

We investigated the effects of punctual A-to-V and A-to-T mutations in the amyloid precursor protein APP, corresponding to position 2 of A\u3b21\u201342. Those mutations had opposite effects on the onset and progression of Alzheimer disease, the former inducing early AD pathology and the latter protecting against the onset of the disease. We applied Static and Dynamic Light Scattering and Circular Dichroism, to study the different mutants in the early stages of the aggregation process, essential for the disease. Comparative results showed that the aggregation pathways differ in the kinetics and extent of the process, in the size of the aggregates and in the evolution of the secondary structure, resulting in fibrils of different morphology, as seen by AFM. Mutated peptides had comparable toxic effects on N2a cells. Moreover, as assessed by X-ray scattering, all of them displayed disordering effects on the internal structure of mixed phospholipids-gangliosides model membranes

UGC 7388: a galaxy with two tidal loops

We present the results of spectroscopic and morphological studies of the galaxy UGC7388 with the 8.1-m Gemini North telescope. Judging by its observed characteristics, UGC7388 is a giant late-type spiral galaxy seen almost edge-on. The main body of the galaxy is surrounded by two faint (\mu(B) ~ 24 and \mu(B) ~ 25.5) extended (~20-30 kpc) loop-like structures. A large-scale rotation of the brighter loop about the main galaxy has been detected. We discuss the assumption that the tidal disruption of a relatively massive companion is observed in the case of UGC7388. A detailed study and modeling of the observed structure of this unique galaxy can give important information about the influence of the absorption of massive companions on the galactic disks and about the structure of the dark halo around UGC7388.Comment: 8 pages, 5 figure