A hands-free stool sampling system for monitoring intestinal health and disease.

Analysis of stool offers simple, non-invasive monitoring for many gastrointestinal (GI) diseases and access to the gut microbiome, however adherence to stool sampling protocols remains a major challenge because of the prevalent dislike of handling one's feces. We present a technology that enables individual stool specimen collection from toilet wastewater for fecal protein and molecular assay. Human stool specimens and a benchtop test platform integrated with a commercial toilet were used to demonstrate reliable specimen collection over a wide range of stool consistencies by solid/liquid separation followed by spray-erosion. The obtained fecal suspensions were used to perform occult blood tests for GI cancer screening and for microbiome 16S rRNA analysis. Using occult blood home test kits, we found overall 90% agreement with standard sampling, 96% sensitivity and 86% specificity. Microbiome analysis revealed no significant difference in within-sample species diversity compared to standard sampling and specimen cross-contamination was below the detection limit of the assay. Furthermore, we report on the use of an analogue turbidity sensor to assess in real time loose stools for tracking of diarrhea. Implementation of this technology in residential settings will improve the quality of GI healthcare by facilitating increased adherence to routine stool monitoring.

Laboratory Demonstration and Preliminary Techno-Economic Analysis of an Onsite Wastewater Treatment System.

Providing safe and reliable sanitation services to the billions of people currently lacking them will require a multiplicity of approaches. Improving onsite wastewater treatment to standards enabling water reuse would reduce the need to transport waste and fresh water over long distances. Here, we describe a compact, automated system designed to treat the liquid fraction of blackwater for onsite water reuse that combines cross-flow ultrafiltration, activated carbon, and electrochemical oxidation. In laboratory testing, the system consistently produces effluent with 6 ≤ pH ≤ 9, total suspended solids (TSS) < 30 mg L-1, and chemical oxygen demand (COD) < 150 mg L-1. These effluent parameters were achieved across a wide range of values for influent TSS (61-820 mg L-1) and COD (384-1505 mg L-1), demonstrating a robust system for treating wastewater of varying strengths. A preliminary techno-economic analysis (TEA) was conducted to elucidate primary cost drivers and prioritize research and development pathways toward commercial feasibility. The ultrafiltration system is the primary cost driver, contributing to >50% of both the energy and maintenance costs. Several scenario parameters showed an outsized impact on costs relative to technology parameters. Specific technological improvements for future prototype development are discussed.

Nutrient removal from human fecal sludge digestate in full-scale biological filters.

There is a great need for simple methods for digestate management for potential household sanitation systems based on anaerobic digestion of minimally diluted fecal waste in countries that lack safe sanitation. Herein, a full-scale three-stage filter for nitrogen and phosphorus removal from anaerobic digester effluent was implemented in Madagascar. It included a trickling filter with crushed charcoal (for aerobic nitrification), a submerged anaerobic filter with bamboo chips (for denitrification), and a submerged filter with scrap iron (for phosphorus removal). All filter materials were sourced locally. Three parallel replicate systems were operated in two sequential 8-week phases for a total of 16 continuous weeks. Though the influent feed was not as expected, with much of nitrogen in the feed coming in as organic N and not as NH3-N, the filters still removed 38-49% of total incoming nitrogen. The filters achieved high rates of nitrogen transformation along with removing solids (73-82% turbidity removal), chemical oxygen demand (67-75% removal), and phosphorus (31-50% removal). Overall, the reaction rates from this full-scale study were in line with previous lab-scale investigations with scaled-down systems, supporting their application in real-world scenarios. Based on this study, simple effluent filters can support nutrient removal for small-scale and onsite fecal sludge treatment systems.

Hypoxia Activated Prodrugs: Factors Influencing Design and Development.

Hypoxia in tumor cells is characterized by a lack of oxygen resulting from reduced blood supply to the surrounding tissue, and is a common characteristic of solid tumors as a consequence of rapid cell growth. Hypoxia in tumors is a predictor of both resistance to chemotherapy and of a metastatic/aggressive form of cancer, and as a result, development of cancer therapies which target hypoxia is of vital importance. One such targeting strategy is the development of hypoxia-activated prodrugs (HAP) which can preferentially release chemotherapeutic agents within hypoxic tumor regions. This targeting strategy is accomplished by attaching a hypoxia activated trigger to a chemotherapeutic agent and under oxygen-poor conditions, the agent (effector) is released into the tumor, while remaining intact in normal tissue, and leaving non-hypoxic cells undamaged. Overall, this strategy can achieve an increased therapeutic benefit over conventional small molecule chemotherapeutic treatments by concentrating the drugs within hypoxic tumor environments, while simultaneously reducing the side-effects and toxicity issues that surround the systemic distribution of traditional drugs on normoxic cells. In this review, we will describe the factors that should be considered when designing an effective HAP, such as the mechanism of prodrug action, the elements that influence the rational design of HAP (i.e. reduction potential), and the activating enzymes of HAP. As part of this description, we will utilize select examples from the literature to reinforce these factors, and make a case for the intelligent design of new HAPs, leading to the development of novel hypoxia targeting chemotherapeutic agents.