Magnetic Immobilization and Growth of Nannochloropsis oceanica and Scenedasmus almeriensis

Microalgae are used in industrial and pharmaceutical applications. Their performance on biological applications may be improved by their immobilization. This study presents a way of cell immobilization using microalgae carrying magnetic properties. Nannochloropsis oceanica and Scenedasmus almeriensis cells were treated enzymatically (cellulase) and mechanically (glass beads), generating protoplasts as a means of incorporation of magnetic nanoparticles. Scanning electron microscopy images verified the successful cell wall destruction for both of the examined microalgae cells. Subsequently, protoplasts were transformed with magnetic nanoparticles by a continuous electroporation method and then cultured on a magnetic surface. Regeneration of transformed protoplasts was optimized using various organic carbon and amino acid supplements. Both protoplast preparation methods demonstrated similar efficiency. Casamino acids, as source of amino acids, were the most efficient compound for N. oceanica protoplasts regeneration in enzymatic and mechanical treatment, while for S. almeriensis protoplasts regeneration, fructose, as source of organic carbon, was the most effective. Protoplasts transformation efficiency values with magnetic nanoparticles after enzymatic or mechanical treatments for N. oceanica and S. almeriensis were 17.8% and 10.7%, and 18.6% and 15.7%, respectively. Finally, selected magnetic cells were immobilized and grown on a vertical magnetic surface exposed to light and without any supplement.

Identification of enamel knot gene signature within the developing mouse molar

In most mammals, the primary teeth develop in utero and the cells capable of contributing to hard surface regeneration are lost before tooth eruption. These cells differentiate through a series of reciprocal induction steps between the epithelium and mesenchyme, initially orchestrated by an epithelial signaling center called the enamel knot. While the factors secreted by this structure are of interest to the dental regeneration and development communities, its small size makes it difficult to isolate for analysis. Here we describe our work to identify the enamel knot from whole E14 molars using publicly available scRNA-seq data. We identified 335 genes differentially expressed in the enamel knot compared to the surrounding tissues, including known enamel knot marker genes. We validated expression of the most highly enriched enamel knot marker genes and identified 42 novel marker genes of the enamel knot which provide excellent targets for future dental regeneration investigations.

Nanocrystalline Oxides NixCo3−xO4: Sub-ppm H2S Sensing and Humidity Effect

In this work, p-type oxide semiconductors, Co3O4 and complex oxides NixCo3−xO4 (x = 0.04, 0.07, 0.1), were studied as materials for sub-ppm H2S sensing in the temperature range of 90–300 °C in dry and humid air. Nanocrystalline Co3O4 and NixCo3−xO4 (x = 0.04, 0.07, 0.1) were prepared by coprecipitation of cobalt and nickel oxalates from nitrate solutions and further annealing at 300 °C. The surface reactivity of the obtained materials toward H2S both in dry and humid atmosphere (relative humidity at 25 °C R.H. = 60%) was investigated using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Sensor measurements showed a decrease in sensor signal toward 1 ppm H2S with an increase in Ni content because of a decrease in chemisorbed surface oxygen species. On the other hand, sensor signal increases for all samples with increasing the relative humidity that depends on reactivity of the surface hydroxyl groups, which stimulate the decomposition of surface sulfites and provide better surface regeneration at higher temperature. This assumption was additionally confirmed by the faster saturation of the conductivity curve and a decrease in the sensor response time in humid air.

Novel Regeneration Approach for Creating Reusable FO-SPR Probes with NTA Surface Chemistry

To date, surface plasmon resonance (SPR) biosensors have been exploited in numerous different contexts while continuously pushing boundaries in terms of improved sensitivity, specificity, portability and reusability. The latter has attracted attention as a viable alternative to disposable biosensors, also offering prospects for rapid screening of biomolecules or biomolecular interactions. In this context here, we developed an approach to successfully regenerate a fiber-optic (FO)-SPR surface when utilizing cobalt (II)-nitrilotriacetic acid (NTA) surface chemistry. To achieve this, we tested multiple regeneration conditions that can disrupt the NTA chelate on a surface fully saturated with His6-tagged antibody fragments (scFv-33H1F7) over ten regeneration cycles. The best surface regeneration was obtained when combining 100 mM EDTA, 500 mM imidazole and 0.5% SDS at pH 8.0 for 1 min with shaking at 150 rpm followed by washing with 0.5 M NaOH for 3 min. The true versatility of the established approach was proven by regenerating the NTA surface for ten cycles with three other model system bioreceptors, different in their size and structure: His6-tagged SARS-CoV-2 spike fragment (receptor binding domain, RBD), a red fluorescent protein (RFP) and protein origami carrying 4 RFPs (Tet12SN-RRRR). Enabling the removal of His6-tagged bioreceptors from NTA surfaces in a fast and cost-effective manner can have broad applications, spanning from the development of biosensors and various biopharmaceutical analyses to the synthesis of novel biomaterials.

Contribution to the Study of Cutting Temperature and Tool Wear

The quality of a machined part strongly depends on the state of wear and the cutting tool. This wear is a major problem in the field of industry. This depends on several factors such as the material to be machined, the cutting tool, the cutting conditions and the machining process. All these factors have the corollary of a significant production of heat at the tool-chip interface. This heat induces accelerated wear of the cutting tool, which considerably limits the performance of the machine tool and is mainly detrimental to both the workpiece and the cutting tool. In this study, the main objective is to contribute to the study of the mechanisms of degradation of the tool by carrying out from an experimental approach based on the techniques of thermocouples located in places studied in order to avoid the influence of parasitic and undesirable parameters such as surface regeneration vibrations, etc. This approach is carried out experimentally by measuring the temperature of the cutting face (friction tool / chip interface). From the results collected during the experiment, we can understand the effects of different turning parameters on the temperature developed on the face of the tool and the appropriate turning conditions to obtain a maximum material removal rate at a lower temperature. The results obtained are represented and analyzed graphically.

Agrin induces long-term osteochondral regeneration by supporting repair morphogenesis

Cartilage loss leads to osteoarthritis, the most common cause of disability for which there is no cure. Cartilage regeneration, therefore, is a priority in medicine. We report that agrin is a potent chondrogenic factor and that a single intraarticular administration of agrin induced long-lasting regeneration of critical-size osteochondral defects in mice, with restoration of tissue architecture and bone-cartilage interface. Agrin attracted joint resident progenitor cells to the site of injury and, through simultaneous activation of CREB and suppression of canonical WNT signaling downstream of β-catenin, induced expression of the chondrogenic stem cell marker GDF5 and differentiation into stable articular chondrocytes, forming stable articular cartilage. In sheep, an agrin-containing collagen gel resulted in long-lasting regeneration of bone and cartilage, which promoted increased ambulatory activity. Our findings support the therapeutic use of agrin for joint surface regeneration.