Chromium(VI) and Oxyanion Remediation Of Vadose Zone Soils With Zero Valent Iron (ZVI) and Biological Reduction

In areas with high industrial development, soil and groundwater are often heavily contaminated with hexavalent chromium [ Cr(VI) ], which commonly occurs as the oxyanions chromate ( CrO42- ) and dichromate ( Cr2O72- ). By itself, Cr(VI) is a common contaminant in various industrial wastes, but other oxyanions such as nitrate [ NO3- ], chlorate [ ClO3- ], and perchlorate [ ClO4- ] can appear with Cr(VI) as co-contaminants based on the type of industrial waste. Cr(VI) and ClO3- occur as co-contaminants in areas where sodium chlorate is manufactured as a bleaching agent for the pulp and paper industry (ERCO Worldwide, 2012). ClO4- and Cr(VI) are common co-contaminants due to their shared applications in electroplating and leather tanning (Sorensen et al., 2006). ClO4-, NO3- and Cr(VI) can occur simultaneously in areas associated with the manufacture, use and disposal of rocket fuel (Rong, 2018). ClO4- and NO3- are also noted to be common co-contaminants in soil and groundwater. (Logan and Lapoint, 2002; Ziv-El and Rittman, 2009; Rong, 2018) Prior to the implementation of RCRA regulations in 1986, wastes containing these contaminants were simply disposed of into the ground, resulting in the contamination of both vadose zone soils and groundwater. Technological options for remediation of vadose zone soils are limited in comparison to groundwater remediation due to lack of development and field testing, with very few options having been successfully implemented in vadose zone treatment (Dresel et al., 2011). This thesis focuses on bioremediation options for vadose zone soils, specifically on the remediation of Cr(VI), NO3-, and ClO3- using biological reduction. The research objective of this study was to assess the viability of bioremediation as an alternative for the removal of Cr(VI) from vadose zone soils using bioremediation methods. Specifically, autotrophic removal through biotic contaminant removal under maintained anaerobic conditions and bio-augmented remediation using zero-valent iron [ ZVI ] were compared to determine which method of treatment was more effective at reducing Cr(VI) and its co-contaminants from vadose zone soils. Microcosm experiments were performed using contaminated fine-grained soils taken from a site in the southwestern United States with high levels of Cr(VI), NO3-, and ClO3-. Biotic reduction tests comparing EOS-Pro and molasses as carbon sources were performed, where soil was divided, mixed with different carbon source and nutrients, prepared and placed in an anaerobic chamber to incubate. A second microcosm test was performed where contaminated soils were mixed with varying amounts of carbon source, nutrients, bacteria and stoichiometric ratios of ZVI to determine which combination of biological reduction and ZVI reduced the most contaminant in the least amount of time. Sample blanks were formed for both experiments to determine which soil amendment enhanced contaminant reduction, if any, and by how much. During the biotic reduction experiments, it was determined that while molasses was more effective in stimulating Cr(VI) removal, neither carbon source had any significant effect on NO3- or ClO3- removal due to incomplete Cr(VI) reduction. Low soil moisture in the samples also inhibited Cr(VI) reduction, which in turn also inhibited soil denitrification and ClO3- reduction. In comparison, the ZVI remediation experiments showed that significant reduction of all three contaminants took place within 50 days of regular treatment of the vadose zone soils, with Cr(VI) and ClO3- being almost completely removed from the soil. As the ZVI experiments involved regular soil wetting to prevent desiccation, it raises the implication that a combination of soil flushing techniques with biological reduction using ZVI could be employed to treat highly contaminated vadose zone soils. Considerations for the use of either ZVI or biological reduction techniques in vadose zone treatment include the costs of using high stoichiometric ratios of ZVI to contaminant, the removal of potential byproducts like iron [ Fe ] and ammonia [ NH3 ], and the ambient soil conditions at the time of treatment

Canine olfactory ensheathing cells from the olfactory mucosa can be engineered to produce active chondroitinase ABC

A multitude of factors must be overcome following spinal cord injury (SCI) in order to achieve clinical improvement in patients. It is thought that by combining promising therapies these diverse factors could be combatted with the aim of producing an overall improvement in function. Chondroitin sulphate proteoglycans (CSPGs) present in the glial scar that forms following SCI present a significant block to axon regeneration. Digestion of CSPGs by chondroitinase ABC (ChABC) leads to axon regeneration, neuronal plasticity and functional improvement in preclinical models of SCI. However, the enzyme activity decays at body temperature within 24–72 h, limiting the translational potential of ChABC as a therapy. Olfactory ensheathing cells (OECs) have shown huge promise as a cell transplant therapy in SCI. Their beneficial effects have been demonstrated in multiple small animal SCI models as well as in naturally occurring SCI in canine patients. In the present study, we have genetically modified canine OECs from the mucosa to constitutively produce enzymatically active ChABC. We have developed a lentiviral vector that can deliver a mammalian modified version of the ChABC gene to mammalian cells, including OECs. Enzyme production was quantified using the Morgan-Elson assay that detects the breakdown products of CSPG digestion in cell supernatants. We confirmed our findings by immunolabelling cell supernatant samples using Western blotting. OECs normal cell function was unaffected by genetic modification as demonstrated by normal microscopic morphology and the presence of the low affinity neurotrophin receptor (p75NGF) following viral transduction. We have developed the means to allow production of active ChABC in combination with a promising cell transplant therapy for SCI repair

Three patients with homozygous familial hypercholesterolemia: Genomic sequencing and kindred analysis.

BackgroundHomozygous Familial Hypercholesterolemia (HoFH) is an inherited recessive condition associated with extremely high levels of low-density lipoprotein (LDL) cholesterol in affected individuals. It is usually caused by homozygous or compound heterozygous functional mutations in the LDL receptor (LDLR). A number of mutations causing FH have been reported in literature and such genetic heterogeneity presents great challenges for disease diagnosis.ObjectiveWe aim to determine the likely genetic defects responsible for three cases of pediatric HoFH in two kindreds.MethodsWe applied whole exome sequencing (WES) on the two probands to determine the likely functional variants among candidate FH genes. We additionally applied 10x Genomics (10xG) Linked-Reads whole genome sequencing (WGS) on one of the kindreds to identify potentially deleterious structural variants (SVs) underlying HoFH. A PCR-based screening assay was also established to detect the LDLR structural variant in a cohort of 641 patients with elevated LDL.ResultsIn the Caucasian kindred, the FH homozygosity can be attributed to two compound heterozygous LDLR damaging variants, an exon 12 p.G592E missense mutation and a novel 3kb exon 1 deletion. By analyzing the 10xG phased data, we ascertained that this deletion allele was most likely to have originated from a Russian ancestor. In the Mexican kindred, the strikingly elevated LDL cholesterol level can be attributed to a homozygous frameshift LDLR variant p.E113fs.ConclusionsWhile the application of WES can provide a cost-effective way of identifying the genetic causes of FH, it often lacks sensitivity for detecting structural variants. Our finding of the LDLR exon 1 deletion highlights the broader utility of Linked-Read WGS in detecting SVs in the clinical setting, especially when HoFH patients remain undiagnosed after WES

Primary Adrenal Lymphoma as a Rare Cause of Primary Adrenal Insufficiency: Challenges in Management and a Review of the Literature

Background/Objective: Primary adrenal lymphoma (PAL) is an aggressive form of lymphoma associated with adrenal insufficiency (AI) in most cases. It requires a histologic confirmation unlike other cases of primary AI. Case Report: We report a case of a 66-year-old man who presented with AI with symptomatic hypotension and hypo-osmolar hyponatremia. Ultrasound and computed tomography scans revealed bilateral bulky adrenal masses that were avid on fluorodeoxyglucose positron emission tomography scan. The diagnosis of PAL was confirmed with adrenal biopsy. He was treated with rituximab-based chemotherapy, which was complicated by several endocrine challenges, including worsening diabetes, multiple adrenal crises, prolonged hyponatremia, and refractory hypokalemia requiring spironolactone. He eventually developed central nervous system disease and was treated with palliative intent. Discussion: AI in the setting of PAL can constitute both diagnostic and therapeutic challenges, including significant electrolyte imbalances as discussed in this case report. Conclusion: It is important to have a high suspicion for PAL, especially in the presence of bilateral adrenal masses and AI. Early adrenal biopsy is required for diagnosis. Multidisciplinary care is vital to manage complications that arise during the disease course and treatment

Constraints on the Atmospheric Circulation and Variability of the Eccentric Hot Jupiter XO-3b

We report secondary eclipse photometry of the hot Jupiter XO-3b in the 4.5~$\mu$m band taken with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. We measure individual eclipse depths and center of eclipse times for a total of twelve secondary eclipses. We fit these data simultaneously with two transits observed in the same band in order to obtain a global best-fit secondary eclipse depth of $0.1580\pm 0.0036\%$ and a center of eclipse phase of $0.67004\pm 0.00013$. We assess the relative magnitude of variations in the dayside brightness of the planet by measuring the size of the residuals during ingress and egress from fitting the combined eclipse light curve with a uniform disk model and place an upper limit of 0.05$\%$. The new secondary eclipse observations extend the total baseline from one and a half years to nearly three years, allowing us to place an upper limit on the periastron precession rate of $2.9\times 10^{-3}$ degrees/day the tightest constraint to date on the periastron precession rate of a hot Jupiter. We use the new transit observations to calculate improved estimates for the system properties, including an updated orbital ephemeris. We also use the large number of secondary eclipses to obtain the most stringent limits to date on the orbit-to-orbit variability of an eccentric hot Jupiter and demonstrate the consistency of multiple-epoch Spitzer observations.Comment: 14 pages, 11 figures, published by Ap

Factor XIII Cross-Linked Hyaluronan Hydrogels for Cartilage Tissue Engineering

ISSN:2373-987

Stable unidimensional arrays of coherent strained islands

We investigate the equilibrium properties of arrays of coherent strained islands in heteroepitaxial thin films of bidimensional materials. The model we use takes into account only three essential ingredients : surface energies, elastic energies of the film and of the substrate and interaction energies between islands via the substrate. Using numerical simulations for a simple Lennard-Jones solid, we can assess the validity of the analytical expressions used to describe each of these contributions. A simple analytical expression is obtained for the total energy of the system. Minimizing this energy, we show that arrays of coherent islands can exist as stable configurations. Even in this simple approach, the quantitative results turn out to be very sensitive to some details of the surface energy.Comment: 24 pages, 7 figures. to be published in Surface Scienc

Glass polymorphism in Glycerol–water mixtures: II. Experimental studies

We report a detailed experimental study of (i) pressure-induced transformations in glycerol–water mixtures at T = 77 K and P = 0–1.8 GPa, and (ii) heating-induced transformations of glycerol–water mixtures recovered at 1 atm and T = 77 K. Our samples are prepared by cooling the solutions at ambient pressure at various cooling rates (100 K s1–10 K h1) and for the whole range of glycerol mole fractions, wg. Depending on concentration and cooling rates, cooling leads to samples containing amorphous ice (wg Z 0.20), ice (wg r 0.32), and/or ‘‘distorted ice’’ (0 o wg r 0.38). Upon compression, we find that (a) fully vitrified samples at wg Z 0.20 do not show glass polymorphism, in agreement with previous works; (b) samples containing ice show pressure-induced amorphization (PIA) leading to the formation of high-density amorphous ice (HDA). PIA of ice domains within the glycerol–water mixtures is shown to be possible only up to wg E 0.32 (T = 77 K). This is rather surprising since it has been known that at wg o 0.38, cooling leads to phase-separated samples with ice and maximally freezeconcentrated solution of wg E 0.38. Accordingly, in the range 0.32 o wg o 0.38, we suggest that the water domains freeze into an interfacial ice, i.e., a highly-distorted form of layered ice, which is unable to transform to HDA upon compression. Upon heating samples recovered at 1 atm, we observe a rich phase behavior. Differential scanning calorimetry indicates that only at wg r 0.15, the water domains within the sample exhibit polyamorphism, i.e., the HDA-to-LDA (low-density amorphous ice) transformation. At 0.15 o wg r 0.38, samples contain ice, interfacial ice, and/or HDA domains. All samples (wg r 0.38) show: the crystallization of amorphous ice domains, followed by the glass transition of the vitrified glycerol–water domains and, finally, the melting of ice at high temperatures. Our work exemplifies the complex ‘‘phase’’ behavior of glassy binary mixtures due to phase-separation (ice formation) and polyamorphism, and the relevance of sample preparation, concentration as well as cooling rates. The presence of the distorted ice (called ‘‘interphase’’ by us) also explains the debated ‘‘drift anomaly’’ upon melting. These results are compatible with the high-pressure study by Suzuki and Mishima indicating disappearance of polyamorphism at P E 0.03–0.05 GPa at wg E 0.12–0.15 [J. Chem. Phys., 2014, 141, 094505]