10 research outputs found
Non-Targeted Analysis of Petroleum Metabolites in Groundwater Using GCĂGCâTOFMS
Groundwater at fuel
release sites often contains nonpolar hydrocarbons
that originate from both the fuel release and other environmental
sources, as well as polar metabolites of petroleum biodegradation.
These compounds, along with other polar artifacts, can be quantified
as âtotal petroleum hydrocarbonsâ using USEPA Methods
3510/8015B, unless a silica gel cleanup step is used to separate nonpolar
hydrocarbons from polar compounds prior to analysis. Only a limited
number of these metabolites have been identified by traditional GCâMS
methods, because they are difficult to resolve using single-column
configurations. Additionally, the targeted use of derivatization limits
the detection of many potential metabolites of interest. The objective
of this research was to develop a nontargeted GCĂGCâTOFMS
approach to characterize petroleum metabolites in environmental samples
gathered from fuel release sites. The method tentatively identified
more than 760 unique polar compounds, including acids/esters, alcohols,
phenols, ketones, and aldehydes, from 22 groundwater samples collected
at five sites. Standards for 28 polar compounds indicate that effective
limits of quantitation for most of these compounds in the groundwater
samples range from 1 to 11 ÎŒg/L
Anti-SOD1 Nanobodies That Stabilize Misfolded SOD1 Proteins Also Promote Neurite Outgrowth in Mutant SOD1 Human Neurons
ALS-linked mutations induce aberrant conformations within the SOD1 protein that are thought to underlie the pathogenic mechanism of SOD1-mediated ALS. Although clinical trials are underway for gene silencing of SOD1, these approaches reduce both wild-type and mutated forms of SOD1. Here, we sought to develop anti-SOD1 nanobodies with selectivity for mutant and misfolded forms of human SOD1 over wild-type SOD1. Characterization of two anti-SOD1 nanobodies revealed that these biologics stabilize mutant SOD1 in vitro. Further, SOD1 expression levels were enhanced and the physiological subcellular localization of mutant SOD1 was restored upon co-expression of anti-SOD1 nanobodies in immortalized cells. In human motor neurons harboring the SOD1 A4V mutation, anti-SOD1 nanobody expression promoted neurite outgrowth, demonstrating a protective effect of anti-SOD1 nanobodies in otherwise unhealthy cells. In vitro assays revealed that an anti-SOD1 nanobody exhibited selectivity for human mutant SOD1 over endogenous murine SOD1, thus supporting the preclinical utility of anti-SOD1 nanobodies for testing in animal models of ALS. In sum, the anti-SOD1 nanobodies developed and presented herein represent viable biologics for further preclinical testing in human and mouse models of ALS
Structural and dielectric properties of Na1âxBaxNb1âx(Sn0.5Ti0.5)xO3 ceramics
Lead-free (1 â x)NaNbO3/xBa(Ti0.5Sn0.5)O3 (x = 0.1, 0.125, 0.15, 0.175, 0.2, and 0.3) ceramics were elaborated by the conventional ceramic technique. Sintering has been made at 1523 K for 2 h. The crystal structure was investigated by X-ray diffraction with CuKα radiation at room temperature. As a function of composition, these compounds crystallize with tetragonal or cubic symmetry. Dielectric measurements show that the materials have a classical ferroelectric behavior for compositions in the range 0.10 †x †0.15 and relaxor one for compositions in the range 0.15 < x †0.30. Temperatures T C or T m decrease as x content increases. The ferroelectric behavior has been confirmed by hysteresis characterization. For x = 0.1, a piezoelectric coefficient d 31 of 42.146 pC Nâ1 was obtained at room temperature. The evolution of the Raman spectra was studied as a function of temperature for x = 0.1