Forensic identification and quantification of oil sands-based bitumen released into a complex sediment environment.

On or about July 25, 2010, approximately 843,000 gal of condensate diluted bitumen (dilbit, a heavy oil) was released into the Kalamazoo River near Marshall, Michigan. As the discharged Line 6B oil migrated downstream the lighter diluent volatilized, formed visible oil droplets/flakes in the water column, became denser than water and/or became aggregated with sediment and migrated to the underlying bottom sediments. Accurate identification and determination of the amount of Line 6B oil present in the sediment was a primary requirement for remediation and allocation of liability. Based on a multi-tiered application of advanced hydrocarbon fingerprinting methodology, key chemical characteristics of the spilled oil were identified that allow for distinguishing heavy oil-related contamination from the complex river sediment background hydrocarbon contamination. It was determined that among the characteristics evaluated, concentration ratios of selected tri-aromatic steranes and triterpanes were most efficient parameters for identification and quantification of the spilled oil in the environment. This quantification approach was successfully applied and validated with field sample results and is consistent with the well-established environmental stability of these petroleum biomarkers and modern hydrocarbon fingerprinting methodology.

Chemical Preservation of Semi-volatile Polycyclic Aromatic Hydrocarbon Compounds at Ambient Temperature: A Sediment Sample Holding Time Study.

Site investigations require the collection and analysis of representative environmental samples to delineate impacts, risks, and remediation options. When environmental samples are collected, concentrations of semi-volatile polycyclic aromatic hydrocarbons (PAHs) begin to change due to several processes, such as evaporation, adsorption, precipitation, photo, and microbial degradation. Preservation techniques are used to minimize these changes between collection and analysis. The most common techniques are refrigeration, freezing, and acidification. In the mid 1970 s, regulatory agencies developed a holding time limit of 14 days for PAHs in soil/sediment samples stored at < 6 °C. The technical basis for this limit is not well defined yet failing to meet this limit may force resampling. This study examined the effectiveness of preservatives at maintaining PAH concentrations in sediment samples to 60 days. Sediment samples were collected at three sites that were impacted with petrogenic and pyrogenic PAHs. Chemically preserved (sodium azide, NaN3) and unpreserved samples were analyzed at defined time intervals from 0 to 60 days. Statistical analysis indicated acceptable preservation of PAHs in the sediment samples preserved with sodium azide for 60 days when maintained at either ambient laboratory temperature or 4 ± 2 °C, and for up to 21 days with no preservative when maintained at 4 ± 2 °C.

Experimental Evaluation of Preservation Techniques for Benzene, Toluene, Ethylbenzene, and Total Xylenes in Water Samples.

An experiment was designed to address the validity of the prescribed maximum allowable holding-time limit of 14 days when acidified at < 2 pH and maintained at 4°C to prevent significant loss of benzene, toluene, ethyl benzene, and xylenes (BTEX) in preserved water samples. Preservation methods prescribed by the United State Environmental Protection Agency were used as well as adaptions of that procedure to determine stability between 3 and 21 days. Water samples preserved at 4°C and pH of < 2 with hydrochloric acid did not result in unacceptable (> 15%) BTEX losses during the study as defined by procedures and statistical methods described by the American Society for Testing and Materials International. In addition, water samples preserved only with acid (pH < 2) at ambient temperatures (20-27°C) also provided acceptable results during the 21-day study. These results have demonstrated the acceptability of BTEX data derived from water samples exceeding the standard holding-time and/or temperature limits.

Architectural overlap between benign endocervix and pattern-A endocervical adenocarcinoma: Are all pattern-A tumors invasive?

Studies on the pattern-based classification for invasive endocervical adenocarcinoma showed that tumors with nondestructive invasion (pattern-A) have a 0% rate of nodal metastases. Our understanding of pattern-A tumors and their distinction from in-situ adenocarcinoma requires further study. Thirteen sections diagnosed independently as pattern-A adenocarcinoma by three gynecologic pathologists, and 14 sections of benign endocervix were selected. Three additional pathologists (reviewers) evaluated a digital image from each section and classified it as pattern-A or benign based on architecture only. To blind the interpretation to cytologic features, nuclei and cytoplasm were obscured using morphometric software (Zen 2011, Carl Zeiss Microscopy, Germany). 13/27 cases (48%; 8 pattern-A, 5 benign) were correctly classified by all reviewers; 19/27 (70%; 10 pattern-A, 9 benign) were correctly classified by ≥2 reviewers. 3/13 pattern-A cases (23%) were interpreted as benign by ≥2 reviewers. Conversely, 5/14 benign cervices (36%) were misinterpreted as pattern-A by ≥2 reviewers. The number of glands per 20× field was higher in pattern-A cases with high reviewer agreement (p=0.004). An abnormal architecture is seen in many pattern-A adenocarcinomas in support of their invasive nature; some, however, have architecture that overlaps with that of benign endocervix thus may actually represent in-situ lesions. Likewise, normal cervix can be architecturally complex and mirror patterns that pathologists would classify as pattern-A if malignant cytologic features were present. Based on this overlap and the nil risk of nodal spread, an emphasis on the non-destructive, rather than the invasive, nature of pattern-A adenocarcinoma is recommended.

Characterization of a far-red analog of ghrelin for imaging GHS-R in P19-derived cardiomyocytes.

Ghrelin and its receptor, the growth hormone secretagogue receptor (GHS-R), are expressed in the heart, and may function to promote cardiomyocyte survival, differentiation and contractility. Previously, we had generated a truncated analog of ghrelin conjugated to fluorescein isothiocyanate for the purposes of determining GHS-R expression in situ. We now report the generation and characterization of a far-red ghrelin analog, [Dpr(3)(octanoyl), Lys(19)(Cy5)]ghrelin (1-19), and show that it can be used to image changes in GHS-R in developing cardiomyocytes. We also generated the des-acyl analog, des-acyl [Lys(19)(Cy5)]ghrelin (1-19) and characterized its binding to mouse heart sections. Receptor binding affinity of Cy5-ghrelin as measured in HEK293 cells overexpressing GHS-R1a was within an order of magnitude of that of fluorescein-ghrelin and native human ghrelin, while the des-acyl Cy5-ghrelin did not bind GHS-R1a. Live cell imaging in HEK293/GHS-R1a cells showed cell surface labeling that was displaced by excess ghrelin. Interestingly, Cy5-ghrelin, but not the des-acyl analog, showed concentration-dependent binding in mouse heart tissue sections. We then used Cy5-ghrelin to track GHS-R expression in P19-derived cardiomyocytes. Live cell imaging at different time points after DMSO-induced differentiation showed that GHS-R expression preceded that of the differentiation marker aMHC and tracked with the contractility marker SERCA 2a. Our far-red analog of ghrelin adds to the tools we are developing to map GHS-R in developing and diseased cardiac tissues.

Desempenho clínico de laminados cerâmicos / Clinical performance of porcelain laminate veneers

A busca por um sorriso perfeito tem se tornado exigência comum na prática clínica, uma vez que um belo sorriso é fator importante para o bem-estar pessoal e social. Para o presente trabalho, foram confeccionados 63 laminados cerâmicos, sendo 34 em pacientes do sexo feminino e 06 do sexo masculino. Os laminados cerâmicos cimentado foram avaliados nos períodos inicial, seis e 12 meses, mediante doze critérios de performance clínica (USPHS). Assim, este estudo tem como objetivo avaliar o desempenho clínico do laminado cerâmico, a fim de contribuir para a prática clínica de sua utilização.

The search for a perfect smile is becoming an increasing concern in daily practice, because a beautiful smile is an important factor for personal and social well-being. For this article, it was fabricated 63 porcelain laminate veneers (and 34 females and 6 males). The porcelain laminates were evaluated after cementation at the following periods: baseline, 6 and 12 months, using twelve criteria of clinical performance (USPHS). The aim of this study was to evaluate the clinical performance of porcelain laminate veneers, in order to encourage their use in routine clinical practice.

Laboratory and field verification of a method to estimate the extent of petroleum biodegradation in soil.

We describe a new and rapid quantitative approach to assess the extent of aerobic biodegradation of volatile and semivolatile hydrocarbons in crude oil, using Shushufindi oil from Ecuador as an example. Volatile hydrocarbon biodegradation was both rapid and complete-100% of the benzene, toluene, xylenes (BTEX) and 98% of the gasoline-range organics (GRO) were biodegraded in less than 2 days. Severe biodegradation of the semivolatile hydrocarbons occurred in the inoculated samples with 67% and 87% loss of the diesel-range hydrocarbons (DRO) in 3 and 20 weeks, respectively. One-hundred percent of the naphthalene, fluorene, and phenanthrene, and 46% of the chrysene in the oil were biodegraded within 3 weeks. Percent depletion estimates based on C(30) 17α,21ß(H)-hopane (hopane) underestimated the diesel-range organics (DRO) and USEPA 16 priority pollutant PAH losses in the most severely biodegraded samples. The C(28) 20S-triaromatic steroid (TAS) was found to yield more accurate depletion estimates, and a new hopane stability ratio (HSR = hopane/(hopane + TAS)) was developed to monitor hopane degradation in field samples. Oil degradation within field soil samples impacted with Shushufindi crude oil was 83% and 98% for DRO and PAH, respectively. The gas chromatograms and percent depletion estimates indicated that similar levels of petroleum degradation occurred in both the field and laboratory samples, but hopane degradation was substantially less in the field samples. We conclude that cometabolism of hopane may be a factor during rapid biodegradation of petroleum in the laboratory and may not occur to a great extent during biodegradation in the field. We recommend that the hopane stability ratio be monitored in future field studies. If hopane degradation is observed, then the TAS percent depletion estimate should be computed to correct for any bias that may result in petroleum depletion estimates based on hopane.

Efeitos das próteses parciais removíveis sobre as condições periodontais / Effects of removable partial dentures on periodontal conditions

A doença periodontal tem como fator etiológico primário o biofilme dental, cujo crescimento pode ser favorecido por grande variedade de fatores retentivos locais como, por exemplo, próteses parciais, que podem alterar a progressão e o risco da doença periodontal. O objetivo deste trabalho foi avaliar o efeito do uso de próteses parciais removíveis (PPRs) sobre as condições clínicas periodontais, comparando os dentes retentores com os dentes não retentores. Foram selecionados 22 pacientes, de ambos os gêneros, da Clínica de Graduação e Especialização em Prótese da Uningá, com indicação de reabilitação com PPRs em apenas uma das arcadas. Os seguintes parâmetros clínicos periodontais, índice de placa (IP), índice gengival (IG), profundidade de sondagem (PS), recessão gengival (RG) e nível clínico de inserção (NCI) foram avaliados em dois períodos distintos: antes da instalação da PPR (T0) e após seis meses da instalação da PPR (T6). A análise dos dados foi feita através do teste t Student pareado considerando-se um nível de significância de 5%. Os resultados revelaram que os dentes retentores apresentaram aumentos significantes para os parâmetros PS, NCI e IP e os dentes não retentores para NCI. Na análise intergrupos inicial, os dentes retentores apresentaram maior RG, IP e IG. Já na análise final, o grupo teste apresentou resultados piores para todos os parâmetros avaliados. De acordo com os resultados pôde-se concluir que após seis meses de uso da PPR houve piora das condições periodontais nos dentes retentores.

Optimizing detection limits for the analysis of petroleum hydrocarbons in complex environmental samples.

To evaluate the sources, transport, bioremediation, fate, and effects of spilled petroleum and petroleum products, environmental studies often measure parent and alkylated polycyclic aromatic hydrocarbons (PAH), alkanes, and chemical biomarkers (e.g., triterpanes). Accurate data for low analyte concentrations are required when environmental samples contain hydrocarbons from multiple sources that need to be resolved and quantified. The accuracy and usefulness of the analyses can be improved by lowering the method detection limits (MDLs) for these compounds. Misidentification of hydrocarbon source can result when the MDLs are too high. Modifications to standard analytical methods (i.e., U.S. Environmental Protection Agency Method 8270) can lower MDLs by factors ranging from 10 to 1000. This reduction has important implications for ecological-risk assessments. Modifications having the greatest impact on the MDL include GCMS analysis in the selected-ion-monitoring mode (SIM), increased sample size, column cleanup of the extract, and decreased preinjection volume (volume of final extract prior to injection into instrument). In one study in which a benthic sediment sample was spiked with low levels of topped (heated to remove more volatile PAH that are naturally enriched in crude oil) Alaska North Slope crude, MDLs for individual PAH analytes and biomarkers were determined to be less than 0.5 ng/g (ppb) dry weight and less than 5 ppb dry weightfor individual alkanes. Similar results were obtained when the sediment was spiked with the 16 EPA priority pollutants. In addition, a method has been developed to estimate MDLs for source-specific alkylated PAH analytes and chemical biomarker compounds for which standards are not commercially available or are prohibitively expensive. These improved analytical techniques have been used to identify and quantify low levels of hydrocarbons, derived from both natural and anthropogenic sources, found in the benthic sediments of Prince William Sound, AK.

Aqueous vapor extraction: a previously unrecognized weathering process affecting oil spills in vigorously aerated water.

Simple evaporation of spilled oil is usually thought to be restricted to the smaller hydrocarbons (<15 carbons). We show that aeration of oil in water, at 22 degrees C, substantially extends this evaporation, leading to the loss of alkanes up to at least hexatricosane (nC36) and of polycyclic aromatic hydrocarbons with at least four rings (e.g., chrysene and its alkylated forms). This phenomenon is apparently related to steam distillation and should be considered as an important candidate pathway to explain the observed weathering of oil spilled from the OSSA II pipeline into the Río Desaguadero on the Bolivian Altiplano (approximately 3700 m), which occurred during a very turbulent flood.