Engineered Vasculature for Cancer Research and Regenerative Medicine.

Engineered human tissues created by three-dimensional cell culture of human cells in a hydrogel are becoming emerging model systems for cancer drug discovery and regenerative medicine. Complex functional engineered tissues can also assist in the regeneration, repair, or replacement of human tissues. However, one of the main hurdles for tissue engineering, three-dimensional cell culture, and regenerative medicine is the capability of delivering nutrients and oxygen to cells through the vasculatures. Several studies have investigated different strategies to create a functional vascular system in engineered tissues and organ-on-a-chips. Engineered vasculatures have been used for the studies of angiogenesis, vasculogenesis, as well as drug and cell transports across the endothelium. Moreover, vascular engineering allows the creation of large functional vascular conduits for regenerative medicine purposes. However, there are still many challenges in the creation of vascularized tissue constructs and their biological applications. This review will summarize the latest efforts to create vasculatures and vascularized tissues for cancer research and regenerative medicine.

Co-digestion of agricultural and municipal waste to produce energy and soil amendment.

In agriculture, manure and cotton gin waste are major environmental liabilities. Likewise, grass is an important organic component of municipal waste. These wastes were combined and used as substrates in a two-phase, pilot-scale anaerobic digester to evaluate the potential for biogas (methane) production, waste minimisation, and the digestate value as soil amendment. The anaerobic digestion process did not show signs of inhibition. Biogas production increased during the first 2 weeks of operation, when chemical oxygen demand and volatile fatty acid concentrations and the organic loading rate to the system were high. Chemical oxygen demand from the anaerobic columns remained relatively steady after the first week of operation, even at high organic loading rates. The experiment lasted about 1 month and produced 96.5 m3 of biogas (68 m3 of CH4) per tonne of waste. In terms of chemical oxygen demand to methane conversion efficiency, the system generated 62% of the theoretical methane production; the chemical oxygen demand/volatile solids degradation rate was 62%, compared with the theoretical 66%. The results showed that co-digestion and subsequent digestate composting resulted in about 60% and 75% mass and volume reductions, respectively. Digestate analysis showed that it can be used as a high nutrient content soil amendment. The digestate met Class A faecal coliform standards (highest quality) established in the United States for biosolids. Digestion and subsequent composting concentrated the digestate nitrogen, phosphorus, and potassium content by 37%, 24%, and 317%, respectively. Multi-substrate co-digestion is a practical alternative for agricultural waste management, minimisation of landfill disposal, and it also results in the production of valuable products.

Anaerobic digestion of municipal solid waste and agricultural waste and the effect of co-digestion with dairy cow manure.

Anaerobic digestion of dairy cow manure (CM), the organic fraction of municipal solid waste (OFMSW), and cotton gin waste (CGW) was investigated with a two-phase pilot-scale anaerobic digestion (AD) system. The OFMSW and CM were digested as single wastes and as combined wastes. The single waste digestion of CM resulted in 62m3 methane/ton of CM on dry weight basis. The single waste digestion of OFMSW produced 37m3 methane/ton of dry waste. Co-digestion of OFMSW and CM resulted in 172m3 methane/ton of dry waste. Co-digestion of CGW and CM produced 87m3 methane/ton of dry waste. Comparing the single waste digestions with co-digestion of combined wastes, it was shown that co-digestion resulted in higher methane gas yields. In addition, co-digestion of OFMSW and CM promotes synergistic effects resulting in higher mass conversion and lower weight and volume of digested residual.

Rapid oxidation of sulfide mine tailings by reaction with potassium ferrate.

The chemistry of sulfide mine tailings treated with potassium ferrate (K2FeO4) in aqueous slurry has been investigated. The reaction system is believed to parallel a geochemical oxidation in which ferrate ion replaces oxygen. This chemical system utilized in a pipeline (as a plug flow reactor) may have application eliminating the potential for tailings to leach acid while recovering the metal from the tailings. Elemental analyses were performed using an ICP spectrometer for the aqueous phase extract of the treated tailings; and an SEM-EDX for the tailing solids. Solids were analyzed before and after treatments were applied. ICP shows that as the mass ratio of ferrate ion to tailings increases, the concentration of metals in the extract solution increases; while EDX indicates a corresponding decrease in sulfur content of the tailing solids. The extraction of metal and reduction in sulfide content is significant. The kinetic timeframe is on the order of minutes.