Acinic cell carcinoma, papillary-cystic variant of the parotid gland: A case report with review of literature

SummaryAcinic cell carcinoma (ACC) is a rare, slow growing, low grade neoplasm of salivary glands and some extra salivary sites. ACC-papillary cystic variant is histologically composed of tumor with papillary and cystic growth patterns, with varying proportions of one or more of 5 cell types which include “hobnail” acinar, intercalated, vacuolated, non-specific glandular and clear cells. The clinical picture is not specific and diagnosis is based on the histopathologic examination. The present case describes ACC—papillary cystic variant and discusses the myriad architectural patterns exhibited by it

Emerging Economies: Equity and Debt Market

This dissertation provides evidence to support the hypothesis that suggests the investment in emerging markets and the valuation of the emerging equity and debt markets. It examines the close relationship between emerging and developed global markets. Capital structure theories and asset pricing model shows the theoretical point of view while selecting and investing in emerging markets, while empirical analysis based on the integration of the emerging markets with international markets. In order to identify the markets for investment purpose, the mean, median, standard deviation and different time series test such as chow test, unit root test, Johansen test, and error correction model is taken into consideration. The major focus is given to India as an emerging market. Due to lack of time and data, only stock markets integration is tested. Indian stock market such as BSE Sensex and NSE Nifty, where as in global markets Nasdaq, Dow Jones, FTSE, Nikkei and Hang Seng is considered

Assessing the Hydraulics of Water Heaters by Adding Fluoride as a Tracer to Inform its Overall Effect on Water Quality

As residential water heaters are the primary source of waterborne disease outbreaks in the U.S. there is a need to better understand how they are contributing to decreased water quality in buildings. Previous work has indicated that intermittent stagnation, low disinfection residual and operation temperatures promote the growth of pathogens in water heaters. The overall effect of hydrodynamics of water heaters on these factors remains unclear. Therefore, a tracer study was performed to determine the effect of and characterize hydraulics of the typical residential water heater on water quality. Controlling temperature and flow rate, a pilot-scale hot water system (50 gal) with specially adapted fittings was used. The fittings allowed for injection of fluoride as a tracer. 4.40 mg/L fluoride solution was injected at room temperature into the inlet line, set at 2.50 gal/min, to derive a step input fluoride concentration. Samples were obtained at the outlet of the tank, then fluoride concentration was measured by ion chromatography. A model was derived numerically in Matlab to validate if the experimental data reflected the behavior of a continuous stirred tank reactor. The data was consistent with the model but deviated at high flow rate and temperature conditions indicating that dispersion effects may be a factor. Additional tests with this tracer can help to better evaluate hydrodynamics of the system and thus its impact on water quality before it reaches the point of use

PAH Analysis of Sediments from Pleasant Run Creek adjacent to a Former Manufactured Gas Plant

Polycyclic aromatic hydrocarbons (PAHs) are known to be toxic and some are even carcinogenic. A prime source of PAHs is coal tar. Coal tar can be found in soils and sediments near former manufactured gas plants (MGPs) or coking facilities. This study involves characterizing the chemical composition and concentrations of PAHs within stream sediments at a former MGP site by Pleasant Run Creek in Indianapolis, Indiana. To characterize the stream sediments, sediment cores were removed from various locations along the stream and sampled with depth. Sample collection was conducted in partnership with the environmental engineering firm, August Mack Environmental. Samples were taken at 2 feet intervals from the surface (0.5 ft.) to a depth of 8 to 12 feet. Since the study is ongoing, samples continue to be processed in the lab to analyze concentrations of 17 PAHs by gas chromatography-mass spectrometry (GC/MS). A comparison between measured concentrations and published risk-based criteria will be performed to determine if observed concentrations pose an environmental risk. The results are expected to indicate significant PAH weathering (i.e., variable composition) in the sediment, due to the water volume and velocity of Pleasant Run Creek being affected by storm events. The results of this project will be used by August Mack Environmental to evaluate remediation strategies

Membrane Pre-treatment Using Chemical Disinfectants in Halide Impaired Waters

The use of membrane filtration processes for desalination, water reuse, and water reclamation techniques are becoming more prevalent given freshwater shortages. However, the treatment of these waters is challenging because of the membranes used in these processes. During nanofiltration and reverse osmosis the membranes undergo biofouling. Reverse osmosis and nanofiltration are high-pressure membrane filtration techniques that treat seawater, brackish waters, and industrial wastewaters. Because of the biofouling, the polyamide thin film needs to be pretreated with chlorine (HOCl/ OCl-) as a disinfectant, but this damages the polyamide membrane. When the free chlorine is in the presence of halide-impaired waters, it changes the chemistry of the membrane thus continuing to damage it. In order to find how halide concentration and other water quality parameters affect nanofiltration and reverse osmosis, this project requires liquid chromatography and mass spectrometry method to analyze different aromatic amine compounds (e.g. benzanilide) with similar structures to the polyamide membrane. The LC/MS is optimized in order to find the limits of detection for each of the compounds. The chlorination reactions are done to quantify how much these compounds react in the presence of free chlorine. Future research with regards to this includes kinetic measurements of compound degradation and by-product formation to see how these compounds are affected by free chlorine over time

Lead in Residential Water Heaters: An Analysis of Lead Dissolution Kinetics in Non-Ideal Aquatic Environments

Lead dioxide, a lead corrosion product, is an important contributor to residential drinking water contamination. A neurotoxin and endocrine disruptor, lead poses serious human health concerns. Despite previous research on water distribution pipes, lead in water heating and softening systems is unexplored. Standard tank water heaters and water softeners have significantly different aquatic environments compared to distribution pipes, due to increased temperature and ion concentration levels. This research verifies the iodometric method for lead dioxide detection and quantifies total lead and dissolved lead(IV) ions over time in simulated water heater and softener environments. Initial experiments confirmed the iodometric method for lead(IV) and measured absorbance with UV-spectrometry. Another set of experiments quantified the dissolved lead(IV) cation in a filtered lead-water mixture by applying the iodometric method to batch reactors, and varying water source (DI, synthetic tap water), temperature (25, 55°C), and NaCl concentration (0.175, 0.584 g/L). Furthermore, each sample was analyzed by ICP-OES to determine the concentration of elemental lead present. The iodometric method resulted in an 80% recovery of dosed lead over one hour. Dissolved lead(IV) ion, conversely, had very little recovery after a week in each batch reactor. Overall, the iodometric method is an accurate and rapid tool for quantifying and comparing dissolution kinetics of total lead dioxide. In contrast, at the temperatures and ionic strength levels investigated, lead(IV) cations may exist in such low concentrations that iodometry may not be an accurate detection method. Future research should consider additional lead species for complete lead dissolution models of water heating and softening systems

Characterization of Landfill Leachate for Enhanced Metal Recovery

Landfills contain a trove of valuable materials, such as critical, precious, and rare earth metals, that are integral to the United State’s economy and national security. The leachate that filters through landfills picks up these materials, which allows for the possibility of recovery. For this research, samples will be analyzed from landfills throughout the Midwestern United States to provide a baseline on water quality constituents, elements present, and microbial activity. Preliminary data for this study was acquired by analyzing samples of landfill leachate from a landfill in northern Indiana. pH readings indicate that the leachate is slightly basic. It also contains around 1-2% total solids. Inductively coupled plasma optical emission spectrometry (ICP-OES) was also used to identify elements present in the samples. Of the 66 elements considered in the analysis, 35 were detectable in quantifiable amounts. The most common elements present were sodium, potassium, magnesium, calcium, boron, and sulfur. Critical elements such as lithium and chromium were also found in the leachate. Future research will develop an integrated method applying microbial bioleaching, physico-chemical processes, and membrane filtration to recover critical elements from landfill leachate

Characterization of Microbial Populations in Landfill Leachate

In the United States, municipal solid waste (MSW) landfills remain a potential mining source of recoverable materials, including but not limited to critical, precious, and rare earth metals found in electronic waste. This is possible due to collectible leachate that filters through MSW landfills, carrying metals, nutrients of value, and microbes—some of which may hold key metal bioleaching properties—within. The purpose of this study is to begin analyzing leachate from MSW landfills in the American Midwest to understand the composition of microbial communities within these landfills. Landfill leachate samples sourced in northern Indiana, representing the landfill process during unique times of operation, were used in this study. Culture-independent studies, utilizing both DNA extraction and PCR for communities of archaea, bacteria, and fungi, were performed on leachate samples. Current results indicate that in 6 of 11 samples, both bacterial and archaeal DNA were likely present, while 1 additional sample yielded only amplified archaeal DNA, and 1 more yielded only amplified bacterial DNA. This implies the presence of both archaea and bacteria which may hold metal bioleaching capabilities. Follow-up research will involve analyzing other Midwestern leachate samples, identifying landfill microbes with metal bioleaching properties, and developing a way to integrate these microbes with membrane filtration and other physico-chemical processes to improve recovery of important metals from leachate

Emerging risks from ballast water treatment: The run-up to the International Ballast Water Management Convention

AbstractUptake and discharge of ballast water by ocean-going ships contribute to the worldwide spread of aquatic invasive species, with negative impacts on the environment, economies, and public health. The International Ballast Water Management Convention aims at a global answer. The agreed standards for ballast water discharge will require ballast water treatment. Systems based on various physical and/or chemical methods were developed for on-board installation and approved by the International Maritime Organization. Most common are combinations of high-performance filters with oxidizing chemicals or UV radiation. A well-known problem of oxidative water treatment is the formation of disinfection by-products, many of which show genotoxicity, carcinogenicity, or other long-term toxicity. In natural biota, genetic damages can affect reproductive success and ultimately impact biodiversity. The future exposure towards chemicals from ballast water treatment can only be estimated, based on land-based testing of treatment systems, mathematical models, and exposure scenarios. Systematic studies on the chemistry of oxidants in seawater are lacking, as are data about the background levels of disinfection by-products in the oceans and strategies for monitoring future developments. The international approval procedure of ballast water treatment systems compares the estimated exposure levels of individual substances with their experimental toxicity. While well established in many substance regulations, this approach is also criticised for its simplification, which may disregard critical aspects such as multiple exposures and long-term sub-lethal effects. Moreover, a truly holistic sustainability assessment would need to take into account factors beyond chemical hazards, e.g. energy consumption, air pollution or waste generation