Characterization and drug delivery of AaltoCell™ microcrystalline cellulose

Microcrystalline cellulose (MCC) is widely utilized in various fields, such as food, pharmaceutics, medicine, and cosmetics. As such an important component, MCC has been deeply studied during recent decades. In this thesis, studies focused on AaltoCell™ MCC, which has been manufactured by a novel AaltoCell™ method. This method is more environmentally friendly than the traditional manufacturing methods, which makes this MCC worthy to be researched for applications. The main tasks of this thesis were characterizing rheological properties of different grades of AaltoCell™ MCC and applying them in controlled drug delivery system as the matrix material. As comparison, a commercial grade of MCC, Avicel® PH-101 was studied. Three types of rheological experiments were conducted to AaltoCell™ MCC, oscillatory stress sweep, frequency sweep, and dynamic viscosity measurement. In the drug release experiments, metronidazole and lysozyme were used as model compounds whose release rates form the gel-like AaltoCell™ matrices were studied. The results of the rheological experiments indicate that rheological properties strongly depend on the concentration of AaltoCell™ MCC, which means that with increasing the concentration, the rheological properties are significantly increased. The results of the drug release experiments indicate that AaltoCell™ MCC could efficiently control diffusion of both large and small molecule which shows great potential for a drug delivery application. In further study, the release profiles of other compounds and effect of concentration on the release profiles could be studied

Receptor Tyrosine Kinase Interaction with the Tumor Microenvironment in Malignant Progression of Human Glioblastoma

Glioblastoma (GBM) is the most malignant brain tumor, characterized with a rapid progression and poor prognosis despite modern therapies. Receptor tyrosine kinase (RTK) is a membrane tyrosine kinase that could be activated by binding ligands with the extracellular domain, and communicating signals according to the tyrosine kinase activity of the intracellular domain. Recent studies revealed that RTKs such as EGFR, PDGFR and MET play key roles in cancer progression through regulation of abundant cellular processes. As transmembrane proteins, RTKs work as a mediator between the extracellular environment and intracellular compartments, translating the tumor microenvironment (TME) signals into the tumor cells. TME is also a critical regulator for the malignant process, lately receiving considerable attention. It is composed of extracellular matrix (ECM), the stromal cells (i.e., endothelial cells, microglia and fibroblasts), secreted factors, and hypoxia environment, etc. Among these, the strong invasion and sustained angiogenesis of GBM are closely related to ECM-receptor interaction and -associated signaling events. In this chapter, we consider the interaction and mechanisms of RTKs and TME in GBM progression, especially the role of ECM-receptor mediated signaling in tumor invasion, hypoxia and angiogenesis, glioma stem cells and tumor metabolism. We then summarize and discuss recent improvements on the approaches of targeting RTK and TME as the therapy in the primary GBM

Modeling Hidden Nodes Collisions in Wireless Sensor Networks: Analysis Approach

This paper studied both types of collisions. In this paper, we show that advocated solutions for coping with hidden node collisions are unsuitable for sensor networks. We model both types of collisions and derive closed-form formula giving the probability of hidden and visible node collisions. To reduce these collisions, we propose two solutions. The first one based on tuning the carrier sense threshold saves a substantial amount of collisions by reducing the number of hidden nodes. The second one based on adjusting the contention window size is complementary to the first one. It reduces the probability of overlapping transmissions, which reduces both collisions due to hidden and visible nodes. We validate and evaluate the performance of these solutions through simulations

Low Cell-Matrix Adhesion Reveals Two Subtypes of Human Pluripotent Stem Cells.

We show that a human pluripotent stem cell (hPSC) population cultured on a low-adhesion substrate developed two hPSC subtypes with different colony morphologies: flat and domed. Notably, the dome-like cells showed higher active proliferation capacity and increased several pluripotent genes' expression compared with the flat monolayer cells. We further demonstrated that cell-matrix adhesion mediates the interaction between cell morphology and expression of KLF4 and KLF5 through a serum response factor (SRF)-based regulatory double loop. Our results provide a mechanistic view on the coupling among adhesion, stem cell morphology, and pluripotency, shedding light on the critical role of cell-matrix adhesion in the induction and maintenance of hPSC

Textile integrable mechanochromic strain sensor based on the interplay of supramolecular interactions

Funding Information: The work was performed in the School of Chemical Engineering at Aalto University. The profilometry measurements were performed in Nanotalo which is a part of the Department of Applied Physics in the School of Science at Aalto University. The work was supported by Academy of Finland SUPER-WEAR project (decision number: 322214). The raw/processed data required to reproduce these findings cannot be shared at this time due to technical or time limitations. Funding Information: The work was performed in the School of Chemical Engineering at Aalto University. The profilometry measurements were performed in Nanotalo which is a part of the Department of Applied Physics in the School of Science at Aalto University. The work was supported by Academy of Finland SUPER-WEAR project (decision number: 322214). Publisher Copyright: © 2021 The AuthorsMechanochromic materials, when exposed to mechanical deformation, undergo a modification of optical properties. This behaviour can stem from either conformational rearrangements, disruptions of intermolecular interactions, or molecular structure changes affecting absorption, emission, or reflection abilities. Here reversible colour change of Disperse Red 1/polyvinylpyrrolidone films resulting from humidity annealing and subsequent stretching is reported. Due to the humidity-induced blue shift of the absorbance peak related to exciton coupling of the chromophores, the tone of films abruptly changes from red to orange. Upon stretching, the gradual disaggregation of the chromophores takes place and therefore the colour switches back to red in a stepless manner. Using either red–green–blue analysis of time lapse photography or UV–Visible measurements, this transformation, which is also well visible by the naked eye, can be followed with high accuracy. This work offers the opportunity to apply the strain sensor inhumid environments to prevent the mechanical failures by showing a colour change in areas subjected to undesired stress. Moreover, dip-coating yarns with mechanochromic coating allows fabrication of functional yarns that change their colour based on their stretching state – thus enabling preparation of colour-changing stretchable textiles was demonstrated.Peer reviewe

Two-Neuron Based Memristive Hopfield Neural Network with Synaptic Crosstalk

Synaptic crosstalk is an important biological phenomenon that widely exists in neural networks. The crosstalk can influence the ability of neurons to control the synaptic weights, thereby causing rich dynamics of neural networks. Based on the crosstalk between synapses, this paper presents a novel two-neuron based memristive Hopfield neural network with a hyperbolic memristor emulating synaptic crosstalk. The dynamics of the neural networks with varying memristive parameters and crosstalk weights are analyzed via the phase portraits, time-domain waveforms, bifurcation diagrams, and basin of attraction. Complex phenomena, especially coexisting dynamics, chaos and transient chaos emerge in the neural network. Finally, the circuit simulation results verify the effectiveness of theoretical analyses and mathematical simulation and further illustrate the feasibility of the two-neuron based memristive Hopfield neural network hardware

Changes in the gut microbiota composition of healthy young volunteers after administration of Lacticaseibacillus rhamnosus LRa05: A placebo-controlled study

The gut microbiota promotes gastrointestinal health in humans; however, the effect of probiotics on the gut microbiota of healthy adults has not been documented clearly. This placebo-controlled study was conducted to assess the effect of Lacticaseibacillus rhamnosus LRa05 supplementation on the gut microbiota of healthy adults. The subjects (N = 100) were randomized 1:1 to receive (1) maltodextrin (placebo, CTL group) and (2) maltodextrin + strain LRa05 (1 × 1010 colony-forming units/day, LRa05 group). The duration of the intervention was 4 weeks, and changes in the gut microbiota from before to after the intervention were investigated using 16S rRNA high-throughput sequencing. In terms of alpha diversity, no significant difference in the composition of the gut microbiota was found between the LRa05 and CTL groups. 16S rRNA sequencing analysis showed that the relative abundance of Lacticaseibacillus significantly increased after supplementation with LRa05. Furthermore, a decreasing trend in the abundance of Sellimonas and a significant decrease in the salmonella infection pathway were observed in the LRa05 group compared with the CTL group. These findings indicate the potential of LRa05 to colonize the human gut and reduce the abundance of harmful bacteria in the microbiota