Chitosan amphiphiles provide new drug delivery opportunities

Chitosan, an acid soluble and renewable biopolymer, was first studied as a drug delivery agent in 1990. This review focuses on the relatively newer self‐assembling chitosan amphiphiles and their use as drug delivery agents. Chitosan amphiphiles, first introduced in the late 1990s, are prepared by conjugating hydrophobic and sometimes additional hydrophilic units to chitosan. These amphiphiles self‐assemble in aqueous media at neutral pH to form micelles, with critical micellar concentrations (CMCs) ranging from 0.09 to 700 µg mL^?1. The CMCs depend on the actual molecular architecture, molecular weight and hydrophobic character, but are typically lower than the values reported for block copolymer amphiphiles. As well as linear amphiphiles in which chitosan is derivatised with hydrophobic pendant groups, new claw amphiphiles have been prepared in which chitosan amphiphiles radiate geometrically from a dendrimer core. These chitosan amphiphiles (linear and claw) have been exploited as drug delivery agents and they increase the oral bioavailability of hydrophobic drugs up to sixfold, deliver hydrophobic drugs to tumours, genes to the liver via the intravenous route, genes to the muscle via the intramuscular routes and small interfering RNAs to tumours via the intratumoural route. Chitosan amphiphile nanoparticles also deliver peptides to the brain via the intravenous and oral routes. © 2014 Society of Chemical Industry     

Recent progress in MoS2 for solar energy conversion applications

In an era of graphene-based nanomaterials as the most widely studied two-dimensional (2D) materials for enhanced performance of devices and systems in solar energy conversion applications, molybdenum disulfide (MoS₂) stands out as a promising alternative 2D material with excellent properties. This review first examined various methods for MoS₂ synthesis. It, then, summarized the unique structure and properties of MoS₂ nanosheets. Finally, it presented the latest advances in the use of MoS₂ nanosheets for important solar energy applications, including solar thermal water purification, photocatalytic process, and photoelectrocatalytic process.     

Comparing ANN and ARIMA model in predicting the discharge of River Opeki from 2010 to 2020

Many attempts have been made in the recent past to model and forecast streamflow using various techniques with the use of time series techniques proving to be the most common. Time series analysis plays an important role in hydrological research. Traditionally, the class of autoregressive moving average techniques models has been the statistical method most widely used for modelling water discharge, but it has been shown to be deficient in representing nonlinear dynamics inherent in the transformation of runoff data. In contrast, the relatively newly improved and efficient soft computing technique artificial neural networks has the capability to approximate virtually any continuous function up to an arbitrary degree of accuracy, which is not otherwise true of other conventional hydrological techniques. This technique corresponds to human neurological system, which consists of a series of basic computing elements called neurons, which are interconnected together to form networks. The aim of the study is to compare the artificial neural network and autoregressive integrated moving average to model River Opeki discharge (1982–2010) and to use the best predictor to forecast the discharge of the river from 2010 to 2020. The performance of the two models was subjected to statistical test based on correlation coefficient (r) and the root‐mean‐square error. The result showed that autoregressive integrated moving average performs better considering the level of root‐mean‐square error and higher correlation coefficient.     

Tissue-Engineering the Fibrous Pancreatic Tumour Stroma Capsule in 3D Tumouroids to Demonstrate Paclitaxel Response

Pancreatic cancer is a unique cancer in that up to 90% of its tumour mass is composed of a hypovascular and fibrotic stroma. This makes it extremely difficult for chemotherapies to be delivered into the core of the cancer mass. We tissue-engineered a biomimetic 3D pancreatic cancer (“tumouroid”) model comprised of a central artificial cancer mass (ACM), containing MIA Paca-2 cells, surrounded by a fibrotic stromal compartment. This stromal compartment had a higher concentration of collagen type I, fibronectin, laminin, and hyaluronic acid (HA) than the ACM. The incorporation of HA was validated with alcian blue staining. Response to paclitaxel was determined in 2D MIA Paca-2 cell cultures, the ACMs alone, and in simple and complex tumouroids, in order to demonstrate drug sensitivity within pancreatic tumouroids of increasing complexity. The results showed that MIA Paca-2 cells grew into the complex stroma and invaded as cell clusters with a maximum distance of 363.7 µm by day 21. In terms of drug response, the IC₅₀ for paclitaxel for MIA Paca-2 cells increased from 0.819 nM in 2D to 3.02 nM in ACMs and to 5.87 nM and 3.803 nM in simple and complex tumouroids respectively, indicating that drug penetration may be significantly reduced in the latter. The results demonstrate the need for biomimetic models during initial drug testing and evaluation.     

Advances in the carbonation of MgO-based binder and CO 2 utilization in the construction industry

Clean Technologies and Environmental Policy - Magnesium oxide carbonation, especially the reactive magnesia (rMgO), is a new paradigm regarded as a green alternative to the traditional Portland...