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PubMed1977

Thin-layer chromatography of chlorophylls and their derivatives on cellulose layers.

A method for the separation and identification of chlorophyll a and b, pheophytin a and b, pheophorbide a and b, chlorin e6, rhodin g7, and the corresponding chlorophyll a' and b' derivatives, as well as the saponification products of pheophorbide a and b, by thin-layer chromatography on commercial cellulose layers on the micro-scale has been developed. Two solvent systems were used: light petroleum (b.p.60-80 degrees)-pyridine (9:1, v/v) and n-heptane-pyridine (7:3, v/v). The former was suitable for chlorophylls, pheophytins and pheophorbides, and the latter for pheophorbides, chlorin, rhodin and their esters. The separation of the derivatives was good and no chemical alteration of the derivatives could be observed. The method is rapid and easy to use and is therefore suitable for checking the purity of derivatives during the preparation of chlorophylls and their derivatives.

Cellulose↗
PubMed1982

The effect of application frequency on epidermal carcinogenesis assays.

Classic mouse skin-painting assays of such highly-complex mixtures as petroleums and synthetic fuels may lead to severe local cytotoxic effects that can alter tumorigenesis. This effect can be particularly disruptive in dose-response studies where a wide range of doses is employed. The experiments described here illustrate that frequency of exposure may be more important than the concentration of individual doses. C3Hf/Bd mice were exposed to 2 shale oils in experiments in which a constant weekly dose was either applied once or divided into 2 or 4 equal parts and applied either twice or 4 times each week. In experiments with either oil, a single weekly application was more effective in total tumor production and less cytotoxic than more frequent application of less-concentrated doses.

Animals↗
PubMed1993

Evaluation of the contribution of chronic skin irritation and selected compositional parameters to the tumorigenicity of petroleum middle distillates in mouse skin.

Two-year skin carcinogenicity studies were conducted in C3H mice to assess the effects of irritation and selected compositional parameters on the carcinogenic potential of four petroleum liquids. Three samples (lightly refined paraffinic oil, LRPO; lightly hydrodesulfurized specialty oil, LHSO; jet fuel, JF) can be generically classified as middle distillates, i.e. distillation occurs between 350 and 700 degrees F (175-370 degrees C). The fourth sample was a Steam Cracked Gas Oil (SCGO) that distilled within the same range. In studies that assess the effects of irritation on tumorigenicity, LRPO was tested undiluted or was diluted to 50% and 25% in either mineral oil (which eliminated irritation of the skin) or toluene (which did not). Undiluted LRPO elicited tumors in 8% of the mice. Both dilution procedures eliminated tumorigenic potential. Thus, it was possible to maintain a visible level of skin irritation equivalent to that elicited by undiluted LRPO without inducing tumors. SCGO elicited a chronic irritant state grossly equivalent to LRPO but was not tumorigenic. Jet Fuel A (JF) was tested undiluted using both a standard skin painting protocol and an intermittent dosing schedule in which treatment was suspended periodically to allow skin irritation to resolve. The standard treatment protocol of JF resulted in both marked skin irritation and tumors in 44% of the mice. However, using the intermittent schedule, the tumor yield was reduced to 2%. Collectively these data demonstrate that tumor formation is not a necessary sequelae to chronic skin irritation. Conversely, prevention of a marked chronic irritant state was accompanied by decreased tumor yield. These data suggest that the chronic irritant state may be a necessary but not sufficient condition for tumor formation. In studies to assess the effects of compositional parameters, a lightly hydrodesulfurized specialty oil (LHSO) similar to LRPO but refined to have negligible levels of sulfur compounds (3 ppm), elicited chronic irritant and tumor responses (10%) similar to LRPO. Thus, the level of sulfur compounds does not appear to affect the tumorigenic activity for products in this boiling range. The SCGO which did not produce tumors contained only aromatic hydrocarbons, a finding consistent with previous reports that aromatics may not be the source of tumorigenic potential in petroleum fractions boiling between 350 and 700 degrees F (175-370 degrees C).

Animals↗
PubMed2004

Nature or petrochemistry?-biologically degradable materials.

Naturally occurring polymers have been utilized for a long time as materials, however, their application as plastics has been restricted because of their limited thermoplastic processability. Recently, the microbial synthesis of polyesters directly from carbohydrate sources has attracted considerable attention. The industrial-scale production of poly(lactic acid) from lactic acid generated by fermentation now provides a renewable resources-based polyester as a commodity plastic for the first time. The biodegradability of a given material is independent of its origin, and biodegradable plastics can equally well be prepared from fossil fuel feedstocks. A consideration of the overall carbon dioxide emissions and consumption of non-renewable resources over the entire life-cycle of a product is not necessarily favorable for plastics based on renewable resources with current technology-in addition to the feedstocks for the synthesis of the polymer materials, the feedstock for generation of the overall energy required for production and processing is decisive.

Bacteria↗
PubMed2000

Vulvar lichen sclerosus: an immunologic study.

OBJECTIVE: To investigate the seroimmunologic (CD3, CD4, CD8 lymphocytes, C3c and C4 complement fractions, and several autoantibodies) and immunohistochemical (T lymphocyte subpopulations, B lymphocytes, natural killer cells, macrophages, immunoglobulin [Ig] G, Ig M, and C3c complement fraction) characteristics of vulvar lichen sclerosus. METHODS: Serum samples from 68 women with histologically proven lichen sclerosus were compared with those from 53 healthy controls, and tissue samples from 14 of 68 women chosen at random were compared with those from 14 of 53 healthy controls. A scoring system was constructed to compare the number of cells in the tissue. RESULTS: Patients had significantly lower counts of circulating lymphocytes CD3 and CD4 than controls (P < .05) and a higher number of autoantibodies (P < .01). Analysis of the tissue samples confirmed a lower number of CD2 cells (two-tailed P = .002 in epidermis, .005 in dermis), CD3 cells (two-tailed P = .001 in epidermis and in dermis), CD4 cells (two-tailed P = .002 in epidermis, .011 in dermis), and CD8 cells (two-tailed P = .002 in epidermis, .051 in dermis) in subjects than in controls. Numbers of monocyte-macrophage cells were similar in the epidermis but different in the dermis (two-tailed P = .003). No natural killer CD56 cells or B lymphocytes (CD19-CD21) were detected in the affected areas. Deposits of IgG, IgM, and C3 were no greater in biopsy specimens of patients than in those of controls. CONCLUSION: Vulvar lichen sclerosus is not caused by a T cell-mediated response, and a viral origin is unlikely. The absence of CD19 and CD21 cells excludes local production of autoantibodies. Our data do not confirm an autoimmune pathogenesis for vulvar lichen sclerosus but help explain why systemic cortisone is of no benefit and justify the use of petroleum jelly to relieve pruritus.

Adult↗
PubMed2003

Cord factor trehalose 6,6'-dimycolate (TDM) mediates trafficking events during mycobacterial infection of murine macrophages.

The persistence of tuberculosis within pulmonary granulomatous lesions is a complex phenomenon, with bacterial survival occurring in a focal region of high immune activity. In part, the survival of the organism may be linked to the ability of the surface glycolipid trehalose 6,6'-dimycolate (TDM; cord factor) to inhibit fusion events between phospholipid vesicles inside the host macrophage. At the same time, TDM contributes to macrophage activation and a cascade of events required for initiation and maintenance of granulomatous responses. This allows increased sequestration of organisms and further survival and persistence within host tissues. Bacterial viability, macrophage cytokine and chemokine response, and intracellular trafficking were investigated in Mycobacterium tuberculosis from which TDM had been removed. Removal of surface lipids led to enhanced trafficking of organisms to acidic compartments; reconstitution of delipidated organisms with either pure TDM or the petroleum ether extract containing crude surface lipids restored normal responses. Use of TDM-coated polystyrene beads demonstrated that TDM can mediate intracellular trafficking events, as well as influence macrophage production of pro-inflammatory molecules. Thus, the presence of TDM may be an important determinant for successful infection and survival of M. tuberculosis within macrophages.

Animals↗
PubMed1978

Exploratory monitoring of air pollutants for mutagenicity activity with the Tradescantia stamen hair system.

The Tradescantia genetic system developed by the late Dr. Arnold H. Sparrow for the study of effects of ionizing radiation is applicable to chemical mutagen detection. Early radiobiological data demonstrated that the stamen hairs were sensitive to as little as 0.25 rad of x-rays and that the number of cells showing a phenotypic change in pigmentation from blue to pink plateaus after approximately 21 days of chronic, low-level irradiation. Exposures to the air pollutants SO(2), NO(2), and O(3) and to vapors of mutagens such as 1,2-dibromoethane (DBE) and ethyl methanesulfonate (EMS) demonstrated the usefulness of the system as a detector of chemical mutagens. A significant number of phenotypic changes was observed following exposures to as little as 0.14 ppm of DBE. The maximum sensitivity of the system is obtained with long-term or chronic exposures because the response increases linearly in proportion to the duration of exposure up to 21 days. To monitor industrial sites for atmospheric mutagens a mobile laboratory was designed to support plant culture in the field. Environment-controlled growth chambers were installed in a trailer so that both ambient air fumigations and concurrent clean-air control exposures could be made. Sites monitored by the mobile laboratory were: Elizabeth, N. J.; Charleston, W. Va.; Birmingham, Ala.; Baton Rouge, La.; Houston, Tex.; Upland, Calif.; Magna, Utah; and Grand Canyon, Ariz. The latter site at Grand Canyon served as a clean air control study. Atmospheric contaminants from petroleum and chemical processing plants generated a significant number of phenotypic pigment changes that were 17 to 31% above the control levels; contaminants from steel and copper smelters, automotive combustion products and photochemical compounds were negative. Chemical analyses are underway to identify the atmospheric mutagens at the sites that showed a positive response.

Air Pollutants↗
PubMed1975

Determination of polybrominated biphenyl residues in dry animal feeds.

A new procedure is described for the determination of polybrominated biphenyls (PBBs) in dry animal feeds and developmental results are discussed. Finely ground feed is packed into a chromatographic column containing Celite and then eluted with methylene chloride. The concentrated extract is cleaned up by elution with petroleum ether through Florisil before gas-liquid chromatographic quantitation. Chromatograms thus obtained were essentially free of the interfering peaks encountered when using AOAC methods for pesticide residues in dry products. Results of feed analyses by the proposed procedure averaged 30% higher than those obtained by AOAC procedures. Recoveries of PBBs from samples fortified at levels of 0.04 to 0.4 ppm ranged from 90 to 104%, with an average of 98%.

Animal Feed↗
PubMed2006

Impact of diesel oil effluent in the mucosal surface of the alimentary canal of Oreochromis nilotica (Linnaeus): a scanning electron microscopic study.

Adverse effects of diesel oil on microanatomical structure of the alimentary canal of O. nilotica were studied using SEM observations. The study revealed irregular arrangement of the stratified epithelial cells along with fragmentation of the normal concentric pattem of microridges of the same cells in buccopharynx and oesophagus. The excessive secretion of mucus of buccopharynx and oesophagus were the salient changes caused by diesel oil pollution. The destruction and degeneration of the mucosal folds of stomach and intestine along with their epithelial cells exhibited a concrete hyperactivity resulting in abundant' secretion of mucus over the microridges of the epithelial cells. In the intestinal region the columnar epithelial cells showed tumefaction and microvilli of the plasma membrane of epithelial cells get heavily damaged. Disarray of the microridges of epithelial cells, excessive secretions of mucus formation of even cell sheet were the most conspicuous changes in rectum. It was concluded that chronic exposure of diesel oil may hamper the absorption of the nutrients through alimentary canal resulting into ill-growth and production of the fish.

Animals↗
PubMed2003

Biological activity in the deep subsurface and the origin of heavy oil.

At temperatures up to about 80 degrees C, petroleum in subsurface reservoirs is often biologically degraded, over geological timescales, by microorganisms that destroy hydrocarbons and other components to produce altered, denser 'heavy oils'. This temperature threshold for hydrocarbon biodegradation might represent the maximum temperature boundary for life in the deep nutrient-depleted Earth. Most of the world's oil was biodegraded under anaerobic conditions, with methane, a valuable commodity, often being a major by-product, which suggests alternative approaches to recovering the world's vast heavy oil resource that otherwise will remain largely unproduced.

Anaerobiosis↗
PubMed1992

Characterization of radioactive petroleum piping scale with an evaluation of subsequent land contamination.

Scale formation in oilfield piping and equipment has been a problem for petroleum companies. In the past, scale waste from cleaning of piping and equipment has been considered nonhazardous. Naturally occurring radioactive material in the form of 226Ra and, to a lesser degree, 228Ra with their associated decay products have recently been discovered in the scale. Due to the lower abundance and short half-life, 228Ra is not addressed in this paper. 226Ra, an alpha emitter, is a potential internal hazard to workers from the inhalation and ingestion of the dust produced during descaling or pipe cleaning operations. Along with this, a higher-than-normal background gamma exposure rate is seen where the pipe cleaning was routinely done. An evaluation of the radiation hazards associated with a retired pipe cleaning field was performed. Gamma exposure rates, 226Ra concentration, and 226Ra leachability were examined using scale containing soil from the field. Radon emanation from the soil was also determined.

Alpha Particles↗
PubMed2006

Transitioning from a pen-and-paper health risk appraisal to an online health risk appraisal at a petroleum company.

Chevron Texaco's Health and Medical Services Department made the decision to use existing technology and transition from a paper health risk appraisal (HRA) to an online questionnaire. A cross-functional team was formed and a year was spent researching online tools to find a vendor who could supply a product best suited to Chevron Texaco's employee workforce. The purpose of this article is to describe the evolution of a paper-based HRA to an online tool as well as describe the project scope and strategy that a team of employees used in selecting the vendor. The article also describes implementation successes, challenges, and lessons learned in using the online tool with an industrial workforce. The strategy that was followed in deploying the Web site along with initial participation rates for this group of industrial employees are described.

Adult↗
PubMed2000

Identification of potential hazards associated with new residential construction.

There were several advantages and limitations of this observational study. The most important advantage of this study was the opportunity to observe residential construction workers performing their jobs. By observing work practices, valuable information was gathered about specific trades and their potential exposure to various chemical and physical agents. This information will be useful in guiding subsequent exposure assessments. Probably the greatest limitation of this study was the lack of participation by homebuilders. Ideally, observations of construction processes would have been more objective if the study included the participation of more than one homebuilder. Aside from one worker who was observed to wear safety glasses, leather gloves, and a dust mask, virtually no personal protective equipment (PPE) was observed onsite. Often small contractors do not have the financial resources necessary to procure the appropriate PPE and issue these items to the workers. Based on hazard prevalence, professional judgement, and the degree of hazardous product use, potential exposures that warrant quantitative sampling efforts during Phase 2 of this study are: bulldozer/backhoe operators--noise, vibration, diesel exhaust; concrete workers--naphtha, mineral spirits, Portland cement; asphalt workers--petroleum hydrocarbons, asphalt, mineral spirits; plumbers--methylethyl ketone, acetone, tetrahydrofuran, cyclohexanone; drywall finishers--total and respirable dust, hexane, acetone; painters--ethylene glycol, VOCs; masons--dust (during the preparation of mortar); floor preparation technicians--total and respirable dust; and ceramic tile installers--toluene, naphtha, silica (from grout powder).

Air Pollution↗
PubMed2000

Temporal variability of organic micropollutants in suspended particulate matter of the River Elbe at Hamburg and the River Mulde at Dessau, Germany.

The compound classes of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and a number of chlorinated hydrocarbons (CHs) in the River Elbe and its tributary Mulde were investigated on the basis of monthly mixed samples of suspended particulate matter (SPM). Covering the period from September 1994 to August 1995, samples from the River Elbe were taken at Hamburg, those from the River Mulde at Dessau. The samples were extracted by supercritical fluid extraction (SFE). Analysis of all substance groups were performed by highperformance liquid chromatography (HPLC), followed by gas chromatography with mass spectrometric detection (GC/MSD). As a statistical approach for the interpretation of data, hierarchical cluster analysis of the individual compound classes were performed to determine differences or similarities between the sampling sites Hamburg and Dessau to find spatial and seasonal concentration patterns. These analysis showed that, with a high significance, the concentration patterns of n-alkanes, PAHs, and CHs were sampling site-specific in both the Elbe and Mulde throughout the entire sampling period. In all cases, clustering of mostly consecutive months indicated continuous, slow changes of input, which moreover showed a constancy with respect to annual cycles. Correlation analysis of pollutant loads with different hydrographic parameters showed a number of linear dependencies of the contaminants with temperature, SPM content, and water discharge. Annual fluxes of particle-bound pollutants were calculated for each sampling site, taking into account the average monthly SPM levels and the water discharge. The particle-bound pollutant loads for the River Elbe at Hamburg were estimated to 13.4 t/a n-alkanes, 4.1 t/a PAHs, and 175. 8 kg/a CHs. The pollutant loads for the River Mulde at Dessau amounted 0.55 t/a n-alkanes, 0.14 t/a PAHs, and 15.5 kg/a CHs during the monitoring period. The input of n-alkanes originated from different sources. The n-alkane pattern of samples of the River Elbe showed a predominance of odd-numbered compounds in the range of C-20 and C-30 originating from terrestrial plants and, depending on the season, high concentrations of C-15 and C-17 due to aquatic organisms. Only a small proportion of n-alkane input originated from petroleum sources. Samples from the River Mulde showed high amounts of the n-alkanes C-12 to C-15, indicating the input of light oil throughout the entire sampling period, constituting approximately 25% of the total n-alkane concentration. PAHs, which are considered combustion products, were widely distributed in all samples. Although the major inputs of PAHs were probably combustion sources and urban runoff, unusually high concentrations were found for some PAHs, which can be explained by point sources. A comparison of the standardized PAH patterns in samples from both stations clearly showed that higher fused ring systems, which mainly originate from combustion processes (four- to six-ring systems), had considerably higher relative concentrations in SPM from the Elbe than from the Mulde, where higher relative concentrations of the two- and three-ring systems were measured. This confirms findings that petroleum input was higher in the Mulde than in the Elbe. Concentrations of chlorinated hydrocarbons in SPM samples from the river Mulde had comparatively high levels. The largest differences were found for p,p'-DDT and its metabolites p,p'-DDD and p,p'-DDE. On average, concentrations of p,p'-DDT, p,p'-DDD, and p,p'-DDE in the Mulde were about 10, 15, and 25 times higher, respectively, than in the Elbe. Concentrations of HCB, which in the samples from Hamburg had the highest concentrations of all CHs, were found to be higher by about a factor of 3 in the Mulde River. The PCB levels in samples from the Mulde and Elbe were about equal, although there were differences in the pattern of PCB congeners.

Alkanes↗
PubMed2003

Wax ester production by bacteria.

The enzymological and genetic aspects of microbial metabolism of hydrocarbons have been extensively revealed. Such molecular information is useful for understanding the bioremediation of oil spill environments and production of hydrocarbon-specific fine chemicals.

Bacteria↗
PubMedDate not supplied

Energy and emission benefits of alternative transportation liquid fuels derived from switchgrass: a fuel life cycle assessment.

We conducted a mobility chains, or well-to-wheels (WTW), analysis to assess the energy and emission benefits of cellulosic biomass for the U.S. transportation sector in the years 2015-2030. We estimated the life-cycle energy consumption and emissions associated with biofuel production and use in light-duty vehicle (LDV) technologies by using the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model. Analysis of biofuel production was based on ASPEN Plus model simulation of an advanced fermentation process to produce fuel ethanol/protein, a thermochemical process to produce Fischer-Tropsch diesel (FTD) and dimethyl ether (DME), and a combined heat and power plant to co-produce steam and electricity. Our study revealed that cellulosic biofuels as E85 (mixture of 85% ethanol and 15% gasoline by volume), FTD, and DME offer substantial savings in petroleum (66-93%) and fossil energy (65-88%) consumption on a per-mile basis. Decreased fossil fuel use translates to 82-87% reductions in greenhouse gas emissions across all unblended cellulosic biofuels. In urban areas, our study shows net reductions for almost all criteria pollutants, with the exception of carbon monoxide (unchanged), for each of the biofuel production option examined. Conventional and hybrid electric vehicles, when fueled with E85, could reduce total sulfur oxide (SO(x)) emissions to 39-43% of those generated by vehicles fueled with gasoline. By using bio-FTD and bio-DME in place of diesel, SO(x) emissions are reduced to 46-58% of those generated by diesel-fueled vehicles. Six different fuel production options were compared. This study strongly suggests that integrated heat and power co-generation by means of gas turbine combined cycle is a crucial factor in the energy savings and emission reductions.

Air Pollution↗