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Perchlorate in Portraits: Quantifying the Disappearance of Perchlorate in Washed Martian Regolith Using Spectroscopic Instrumentation
No full textOn Earth, perchlorate ions are found naturally in isolated deposits. However, on Mars, they are much more widely distributed (1-2 wt%). If plants were to be grown in Martian regolith containing \u3e1 wt% perchlorate, growth would be stunted or halted entirely (Oze et al. 2021). Those plants that do grow would rapidly absorb the perchlorate, making them hazardous to human health upon ingestion. Three Regolith simulants from Exolith Labs® reflecting the elemental composition of Martian regolith were used to compare the efficacy of deionized water, HCl, Acetic Acid, and EDTA at removing 1 wt% perchlorate, sulfates, and nutrient metals. MGS-1 and MGS-1S regolith simulants are Mars Global Simulants that represent the average sediment composition across the Martian planet. MGS-1S is supplemented with additional sulfates. JEZ-1 regolith simulant is representative of the Equatorial Jezero Delta Crater, which is thought to be an ancient sea bed.
Since the concentration of perchlorate in washed samples is below the limit of detection of the Methylene Blue Chemical Spot Test, spectroscopic instrumentation is required to identify and quantify the loss of perchlorate and sulfates in the regolith simulant. ICP-OES permitted the successful quantification of nutrient metals, however chlorine and sulfur could not be quantified at the tested wavelengths. Using XRF, chlorine and sulfur were quantified from dried samples of regolith that had been fully washed. In addition, sulfates could be quantified with HACH® protocols as a proxy for perchlorate due to the similar solubilities of the two compounds. ATR-FTIR and HPLC-IC could both detect highly resolved perchlorate peaks in sediment washes, and HPLC-IC could also detect sulfate peaks. FTIR-DRIFTS and RAMAN spectra obtained from dried regolith exhibited too much background fluorescence for any reliable quantification of either perchlorate or sulfate
Mercury bioaccumulation in top-level predatory fishes from marine and freshwater environments
Get PDFMercury is a widespread environmental contaminant that poses a threat to human and wildlife health. Mercury concentrations ([Hg]) may be elevated in fish tissues due to individual bioaccumulation and biomagnification in the food web. This study examined Hg bioaccumulation rates in striped bass (SB) and largemouth bass (LMB): top-level predatory fishes in marine and freshwater environments. SB, LMB, and their prey were collected in Rhode Island waters from 2006 to 2023 using rod & reel, electrofishing, and trawling methods. Age (yr) was determined for each fish based on measurements of total lengths (TL; cm) in the laboratory (LMB: 15-57 cm, 1-18 yr, n = 412; SB: 26-105 cm, 2-12 yr, n = 231). Muscle tissue excised from SB and LMB, as well as prey whole bodies, were analyzed for total [Hg] (ppm wet weight) using automated atomic-absorption spectroscopy. Total [Hg] of SB were significantly lower than LMB despite no difference in the species’ trophic position, as calculated from stable nitrogen isotopes, and SB being older and larger in body size. Prey of LMB (juvenile conspecifics, sunfishes, and crayfish) had higher [Hg] compared to SB prey (forage fish, squid, and crabs), which may explain interspecific differences in Hg contamination. Growth dilution and variations in feeding and excretion rates may also contribute to higher [Hg] in LMB relative to SB. Lastly, total [Hg] of legally harvestable LMB and SB routinely exceeded the US EPA threshold level; thus, frequent consumption of either species may adversely affect human health
Determining the probiotic potential of Pseudoalteromonas rubra against native pathogens
No full textTropical corals host diverse and specific microbiomes that modulate coral fitness, and many microbes play a protective role against pathogens. Two strains of the bacteria Pseudoalteromonas rubra (KB1 and CH007) were isolated from seawater and crustose coralline algae (CCA) in the temperate coral (Astrangia poculata) culturing tanks in Roger Williams University Wet Lab. P. rubra is thought to be protective to tropical corals, via production of the prodigiosins and N-acyl-homoserine lactones. Additionally, P. rubra induces larval settlement in at least one tropical coral species. P. rubra KB1 and CH007 inhibit growth of several species of Vibrio, including known coral, finfish, and shellfish pathogens. An exposure assay was conducted and P. rubra KB1 and CH007 were found to be not lethal to A. poculata. Exposure to P. rubra significantly altered the A. poculata microbiome composition, including increases in bacteria involved in sulfur cycling and likely antibacterial production. However, exposure also was correlated with decrease in known beneficial associates. Coral mucus and seawater microbiomes resembled one another at some, but not all, time points during exposure, and there was significant strain-dependent variation in the impact on A. poculata microbiome composition and diversity. These data lay the groundwork in developing P. rubra as a probiotic treatment and in understanding the molecular mechanisms of any benefit that P. rubra may confer to corals. Due to the resistance of A. poculata against V. coralliilyticus in the lab, the sea anemone, Exaiptasia diaphana, was selected as an experimental system to assess P. rubra’s capacity for disease prevention and/or mitigation. Exaiptasia diaphana was exposed to high concentrations (108 cells/ml) of the pathogen V. coralliilyticus, and dosed with P. rubra either before or after the V. coralliilyticus exposure. Preliminary data showed that pretreatment with P. rubra 12 hours before V. coralliilyticus did not reduce the Vibrio-induced mortality. However, anemones treated with P. rubra 12 hours after V. coralliilyticus exposure showed a decrease in mortality compared to those exposed to the pathogen alone
Climate Change Alters Thermal Dynamics of Rhode Island Lakes
No full textLakes are vital freshwater resources that, as reservoirs of water and energy, are sensitive to changes in climate across timescales. Past research has demonstrated that climate change has already impacted lake temperatures and mixing, especially in relatively large and deep lakes around the world. Comparatively, Rhode Island lakes and ponds are relatively shallow with small surface areas. The combination of these features may result in unique sensitivity to climate not captured by prior studies. To further investigate this, we used the General Lake Model (GLM), a one dimensional energy and water balance model, to simulate thermal dynamics of two representative lakes. Specifically, we parameterized our models to represent the bathymetry of Deep Pond and Watchaug Pond, which are both located in southwest RI, have similar maximum depths (~11 m), and markedly different surface areas (8 and 233 hectares, respectively). We then forced the models with historical hourly meteorological data from Warwick, RI to generate daily temperature profiles of both lakes. Our preliminary analysis of these simulations reveal that from 1970–2023, mean surface temperature, number of days stratified per year, and resistance to mixing of surface and bottom waters have all likely increased for both lakes. Notably, we found evidence that the larger lake may have experienced a more substantial change in annual mixing patterns, especially in terms of the occurrence, strength, and persistence of summer stratification. Overall, our preliminary work suggests that climate change may have already altered the thermal dynamics of lakes and ponds in RI and, importantly, that the extent of changes in mixing regimes may differ depending on size-depth characteristics. This study serves as a foundation from which we will further validate model performance and assess the seasonally-specific changes in thermal dynamics and ecosystem consequences among many RI lakes
Investigating the effect of rapamycin and 2,5 dideoxy adenosine on the lifespan of Brachionus plicatilis
No full textUnderstanding the basic biology of aging and underlying molecular events that result in deterioration of physiology may lead to treatments for chronic age-related health conditions in people. Rotifers (Brachionus plicatilis) are microscopic aquatic organisms recently developed by our lab as a model organism for studying metabolic and biochemical pathways implicated in the aging process. Rotifers have previously been used in ecotoxicology as sentinels for monitoring water quality given their heightened sensitivity to waterborne contaminants. Based upon this application, we hypothesize that rotifers are excellent models in screens to identify drugs capable of extending health and longevity. Other advantages of this model organism include a short laboratory life span of 2-3 weeks and parthenogenic reproduction resulting in genetically identical generations. Through the utilization of high-throughput robotic drug discovery and hypothesis driven experimentation, we test the effect of pharmaceuticals such as rapamycin and 2,5 dideoxy adenosine on the lifespan of rotifers to target adenylyl cyclase activity as well as the target of rapamycin (TOR) kinase pathway with previous literature suggesting an expansion of lifespan. We provide evidence that rotifers are effective model organisms for pharmacologic screens in discovery of new drugs capable of affecting lifespan or other phenotypes of interest
Law School News: RWU Receives $750,000 Gift From Hassenfeld Family Foundation To Strengthen Law School\u27s Regional Impact And Reputation 11-13-2024
Get PDFFindings of research studies on reading comprehension between digital and print formats: Implications for the NextGen Bar Exam
Get PDFSpinning and corkscrewing of oceanic macroplankton revealed through in situ imaging
No full textHelical motion is prevalent in nature and has been shown to confer stability and efficiency in microorganisms. However, the mechanics of helical locomotion in larger organisms (\u3e1 centimeter) remain unknown. In the open ocean, we observed the chain forming salp, Iasis cylindrica, swimming in helices. Three-dimensional imaging showed that helicity derives from torque production by zooids oriented at an oblique orientation relative to the chain axis. Colonies can spin both clockwise and counterclockwise and longer chains (\u3e10 zooids) transition from spinning around a linear axis to a helical swimming path. Propulsive jets are non-interacting and directed at a small angle relative to the axis of motion, thus maximizing thrust while minimizing destructive interactions. Our integrated approach reveals the biomechanical advantages of distributed propulsion and macroscale helical movement
Investigation of the Permeability of Antiretroviral Drugs Lamivudine and Valganciclovir via Single-Pass Intestinal Perfusion (SPIP) Method
No full textIntroduction: Antiretroviral medications are widely used to treat HIV infections. Lamivudine (3TC) is prescribed for HIV-1 infection management in adults and pediatrics, while valganciclovir (VGC) is a prodrug of ganciclovir derived from valine. Methods: The Biopharmaceutics Classification System (BCS) estimates the contributions of intestinal permeability, dissolution, and solubility in oral drug absorption. Intestinal permeability refers to a substance\u27s capacity to pass through the protective layer of cells in the intestine. The intestinal permeability of 3TC and VGC was analyzed and categorized using the single-pass intestinal perfusion technique according to the BCS in male Sprague Dawley rats, and a reversed-phase HPLC method was validated for precise and accurate measurement. Results: According to the BCS, 3TC and VGC have been classified as having low permeability when compared to metoprolol tartrate, which is classified as Class I with good permeability and resolution. Conclusion: The permeability values derived from this work can be valuable in exposure assessment models
India and China: Population Futures
No full textA country’s demographic profile is the foundation of its economic development and political power. Under auspicious demographic conditions, states will be able to design domestic policies that capitalize on a growing national economy and implement foreign policies that seek to enhance the state’s position in the international system over the long term. Adverse demographic conditions, on the other hand, severely constrain the range of options available to states in domestic and foreign policy. Many rising powers today suffer from adverse demographic trends (e.g., declining labor force populations and shrinking tax bases) resulting in domestic policies designed to redress immediate problems, but which tend to hamper future growth. This chapter explores the relationship between demographics and economic growth, focusing on China and Russia. The evidence suggests that China will likely not outpace the United States and its Western allies because its demographics will make escaping the middle-income trap extremely difficult