An Increase in Membrane Cholesterol by Graphene Oxide Disrupts Calcium Homeostasis in Primary Astrocytes

The use of graphene nanomaterials (GNMs) for biomedical applications targeted to the central nervous system is exponentially increasing, although precise information on their effects on brain cells is lacking. In this work, the molecular changes induced in cortical astrocytes by few‐layer graphene (FLG) and graphene oxide (GO) flakes are addressed. The results show that exposure to FLG/GO does not affect cell viability or proliferation. However, proteomic and lipidomic analyses unveil alterations in several cellular processes, including intracellular Ca²⁺ ([Ca²⁺]_i) homeostasis and cholesterol metabolism, which are particularly intense in cells exposed to GO. Indeed, GO exposure impairs spontaneous and evoked astrocyte [Ca²⁺]_i signals and induces a marked increase in membrane cholesterol levels. Importantly, cholesterol depletion fully rescues [Ca²⁺]_i dynamics in GO‐treated cells, indicating a causal relationship between these GO‐mediated effects. The results indicate that exposure to GNMs alters intracellular signaling in astrocytes and may impact astrocyte–neuron interactions.     

Robust projected clustering

Projected clustering partitions a data set into several disjoint clusters, plus outliers, so that each cluster exists in a subspace. Subspace clustering enumerates clusters of objects in all subspaces of a data set, and it tends to produce many overlapping clusters. Such algorithms have been extensively studied for numerical data, but only a few have been proposed for categorical data. Typical drawbacks of existing projected and subspace clustering algorithms for numerical or categorical data are that they rely on parameters whose appropriate values are difficult to set appropriately or that they are unable to identify projected clusters with few relevant attributes. We present P3C, a robust algorithm for projected clustering that can effectively discover projected clusters in the data while minimizing the number of required parameters. P3C does not need the number of projected clusters as input, and can discover, under very general conditions, the true number of projected clusters. P3C is effective in detecting very low-dimensional projected clusters embedded in high dimensional spaces. P3C positions itself between projected and subspace clustering in that it can compute both disjoint or overlapping clusters. P3C is the first projected clustering algorithm for both numerical and categorical data.     

Study on template removal from silicalite-1 giant crystals

The formation of silicalite-1 giant crystals with a size of up to 3 mm can be achieved by controlling the factors affecting the nucleation and crystallization process using a piece of tube of quartz glass as the silica source under hydrothermal conditions. Once prepared and characterized by scanning electron and optical microscopy, thermogravimetry and single crystal powder X-ray diffraction, a challenge that remains is the removal of the template giving rise to colourless and crack-free crystals. As pointed out by stereoscopical, optical and fluorescence confocal optical microscopies, this was achieved in this study by the calcination protocols developed, involving the use of pure O₂ and 5% of O₂ in Ar and O₂-O₃ (1.5% of O₃), maximum temperatures of 400 °C and heating rates as low as 0.5 °C/min.     

The effectiveness of using a robotics class to foster collaboration among groups of children with autism in an exploratory study

This article describes an exploratory study involving the design of an after-school robotics class for groups of children at the higher-functioning end of the autistic spectrum. The aim of the study was to foster collaboration among the children in the context of a class where they programmed Lego robots under the guidance of an experimenter. The class took place once a week over several months and used many different measures to assess the children’s collaborative behaviours. Detailed analysis of behavioural data is presented, and despite the small sample size, our findings suggest that the number of potentially collaborative behaviours the children displayed during a class is more strongly related to the amount of enjoyment the children derived from the classes than to the number of classes in which the children participated. Parallel-run, free-form drawing sessions conducted before certain classes gave some indication that these behavioural changes partly generalized to a different context. Additionally, many of the children in the class either found their experiences in class to be helpful in other social interactions or expected them to be.     

Extensional rheology,cellular structure,mechanical behavior relationships in HMS PP/montmorillonite foams with similar densities

The main goal of this work is to analyze the relationships between the extensional rheological behavior of solid nanocomposites based on high melt strength polypropylene (HMS PP) and montmorillonites (MMT) and the cellular structure and mechanical properties of foams produced from these materials. For this purpose two systems have been analyzed. The first one incorporates organomodified MMT and a compatibilizer and the second system contains natural clays and is produced without the compatibilizer. Results indicate that the extensional rheological behavior of both materials is completely different. The strain hardening of the polymer containing organomodified clays decreases as the clay content increases. As a consequence, the open cell content of this material increases with the clay content and hence, the mechanical properties get worse. However, in the materials produced with natural clays this relationship is not so clear. While no changes are detected in the extensional rheological behavior by adding these particles, the nano-filled materials show an open cell structure, opposite to the closed cell structure of the pure polymer, which is caused by the fact of having particle agglomerates with a size larger than the thickness of the cell walls and a poor compatibility between the clays and the polymer.     

Implication of COVID-19 on Erythrocytes Functionality: Red Blood Cell Biochemical Implications and Morpho-Functional Aspects

Several diseases (such as diabetes, cancer, and neurodegenerative disorders) affect the morpho-functional aspects of red blood cells, sometimes altering their normal metabolism. In this review, the hematological changes are evaluated, with particular focus on the morphology and metabolic aspects of erythrocytes. Changes in the functionality of such cells may, in fact, help provide important information about disease severity and progression. The viral infection causes significant damage to the blood cells that are altered in size, rigidity, and distribution width. Lower levels of hemoglobin and anemia have been reported in several studies, and an alteration in the concentration of antioxidant enzymes has been shown to promote a dangerous state of oxidative stress in red blood cells. Patients with severe COVID-19 showed an increase in hematological changes, indicating a progressive worsening as COVID-19 severity progressed. Therefore, monitored hematological alterations in patients with COVID-19 may play an important role in the management of the disease and prevent the risk of a severe course of the disease. Finally, monitored changes in erythrocytes and blood, in general, may be one of the causes of the condition known as Long COVID.     

Electrospinning as a useful technique for the encapsulation of living bifidobacteria in food hydrocolloids

This study shows the feasibility of using the electrospinning technique to encapsulate Bifidobacterium strains in food hydrocolloids for functional food applications. Specifically, a protein (whey protein concentrate) and a carbohydrate (pullulan) were used as encapsulation materials due to their ability to form micro, submicro and nanocapsules through an electrospraying process. The concentration of both biopolymers was adjusted so as to obtain functional hybrid capsules easier to handle as a food ingredient. Microcapsules containing the strain Bifidobacterium animalis subsp. lactis Bb12 were prepared from solutions of the hydrocolloids both, in PBS and in skimmed milk, resulting in structures with different morphology and protection ability. The morphological features of the obtained systems were characterized and the viability of the encapsulated probiotic was compared to that of the same bacterium in liquid medium (PBS or skimmed milk) and freeze-dried. Freeze-drying of a mix containing bacterium and the biopolymers was also carried out for comparison. The viability tests were conducted at two different temperatures (20 °C and 4 °C) and at various relative humidities (0%, 11%, 53% and 75%). The results showed that, as expected, the survival of the bifidobacterial strain increased when stored in skimmed milk or obtained from skimmed milk solutions in comparison with those stored or obtained from PBS. Encapsulation through electrospraying substantially increased the viability of the bifidobacterial strain, especially at 20 °C. WPC demonstrated greater protection ability as encapsulation material than pullulan as it effectively prolonged the survival of the cells even at high relative humidity.     

Neurocognitive evidence for test equity in an academic listening assessment

Behaviormetrika - The present study explored the potential of a new neurocognitive approach to test equity which integrates evidence from eye-tracking and functional near-infrared spectroscopy with...     

Cholesterol-Containing Liposomes Decorated With Au Nanoparticles as Minimal Tunable Fusion Machinery

Membrane fusion is essential for the basal functionality of eukaryotic cells. In physiological conditions, fusion events are regulated by a wide range of specialized proteins, operating with finely tuned local lipid composition and ionic environment. Fusogenic proteins, assisted by membrane cholesterol and calcium ions, provide the mechanical energy necessary to achieve vesicle fusion in neuromediator release. Similar cooperative effects must be explored when considering synthetic approaches for controlled membrane fusion. We show that liposomes decorated with amphiphilic Au nanoparticles (AuLips) can act as minimal tunable fusion machinery. AuLips fusion is triggered by divalent ions, while the number of fusion events dramatically changes with, and can be finely tuned by, the liposome cholesterol content. We combine quartz-crystal-microbalance with dissipation monitoring (QCM-D), fluorescence assays, and small-angle X-ray scattering (SAXS) with molecular dynamics (MD) at coarse-grained (CG) resolution, revealing new mechanistic details on the fusogenic activity of amphiphilic Au nanoparticles (AuNPs) and demonstrating the ability of these synthetic nanomaterials to induce fusion regardless of the divalent ion used (Ca²⁺ or Mg²⁺). The results provide a novel contribution to developing new artificial fusogenic agents for next-generation biomedical applications that require tight control of the rate of fusion events (e.g., targeted drug delivery).