Maine Space Grant Consortium

JC polyomavirus (JCPyV) establishes a persistent, asymptomatic kidney infection in most of the population. However, JCPyV can reactivate in immunocompromised individuals and cause progressive multifocal leukoencephalopathy (PML), a fatal demyelinating disease with no approved treatment. Mutations in the hypervariable non-coding control region (NCCR) of the JCPyV genome have been linked to disease outcomes and neuropathogenesis, yet few metanalyses document these associations. Many online sequence entries, including those on NCBI databases, lack sufficient sample information, limiting large-scale analyses of NCCR sequences. Machine learning techniques, however, can augment available data for analysis. This study employs a previously compiled dataset of 989 JCPyV NCCR sequences from GenBank with associated patient PML status and viral tissue source to train multilayer perceptrons for predicting missing information within the dataset. The PML status and tissue source models were 100% and 87.8% accurate, respectively. Within the dataset, 348 samples had an unconfirmed PML status, where 259 were predicted as No PML and 89 as PML sequences. Of the 63 sequences with unconfirmed tissue sources, eight samples were predicted as urine, 13 as blood, and 42 as cerebrospinal fluid. These models can improve viral sequence identification and provide insights into viral mutations and pathogenesis.

The Distiller Calcium Limiter (DCaL) system was designed to remove calcium scale constituents from urine. The DCaL is based on a process called electrodialysis. In electrodialysis, water is desalinated by the transport of ions through ion exchange membranes under the driving force of an electric potential between a cathode and an anode. The DCaL system uses electrodialysis with ion replacement where ions of insoluble inorganic salts, such as CaSO4, exchange cations (Ca) or anions (SO4) with soluble salts, such as NaCl (Na and Cl), to prevent the precipitation of inorganic solids. Removal of calcium from urine is particularly important for spacecraft wastewater treatment systems due to the precipitation of calcium scale solids on heat transfer surfaces. Operation of the International Space Station (ISS) Urine Processor Assembly (UPA) has demonstrated that calcium-based scale is the limiting factor to achieving high water recovery ratios. The DCaL process removes calcium, which would ultimately prevent calcium-based precipitation from occurring and subsequently the formation of calcium scale. The objective of this study was to evaluate the effectiveness of the DCaL system in removing calcium scale precursors from spacecraft wastewater (a urine-based solution). Three pretreatment methods were tested including: the US ISS pretreatment (sulfuric acid and Oxone), AES pretreatment (Bronopol PESTANAL and maleic acid) as well as the US/Russian Chromic Acid ISS pretreatment. The results indicated that the DCaL system does remove calcium scale constituents and could enable a distillation system to achieve a water recovery ratio above 85%; however, the pretreatment method, operating conditions (production rate and feed pH), and fouling of the membrane play an important role in system performance.

NASA plans to build a permanent space station on the moon to explore its surface. The surface of the moon is covered in lunar dust, which consists of fine particles that contain silicon, aluminum and titanium, among others. Because this will be a manned base, the potential toxicity of this dust has to be studied. Also, toxicity standards for potential exposure have to be set. To properly address the potential toxicity of lunar dust we need to understand the toxicity of its individual components, as well as their combined effects. In order to study this we compared NASA simulant JSC-1AVF (volcanic ash particles), that simulates the dust found on the moon, to aluminum, the 3rd most abundant component in lunar dust. We tested the cytotoxicity of both compounds on human lung and skin fibroblasts (WTHBF-6 and BJhTERT cell lines, respectively). Aluminum oxide was more cytotoxic than lunar dust to both cell lines. In human lung fibroblasts 5, 10 and 50 g/sq cm of aluminum oxide induced 85%, 61% and 30% relative survival, respectively. For human skin fibroblasts the same concentrations induced 58%, 41% and 58% relative survival. Lunar dust was also cytotoxic to both cell lines, but its effects were seen at higher concentrations: 50, 100, 200 and 400 g/sq cm of lunar dust induced a 69%, 46%, 35% and 30% relative survival in the skin cells and 53%, 16%, 8% and 2% on the lung cells. Overall, for both compounds, lung cells were more sensitive than skin cells. This work was supported by a NASA EPSCoR grant through the Maine Space Grant Consortium (JPW), the Maine Center for Toxicology and Environmental Health., a Fulbright Grant (JM) and a Delta Kappa Gamma Society International World Fellowship (JM).