Abstract  Due to the exceptional advantages of sol-gel process, organically modified silane (ormosil) coating has been applied to study the corrosion protection of aluminum alloy. In the present work, GPTMS/MTMS sol-gel solution was prepared by hydrolysis and condensation of 3-glycidoxypropyltrimetoxysilane (GPTMS) and methyltrimethoxysilane (MTMS) in aqueous solution of 0.05 M acetic acid in molar ratios 3: 1. To prepare the ormosil coating solutions, a crosslinking agent hexamethoxymethylmelamine (HMMM) and a blocked acid catalyst p- toluenesulphonic (p-TSA) were combined with the sol-gel solution. Aluminum substrates were dip coated and cured at 130 degrees C for 45 min. Effectiveness of HMMM as a crosslinking agent was analyzed by evaluating corrosion resistance, chemical resistance and hydrophobicity of coating using potentiodynamic polarization method, immersion test and water contact angle, respectively. UV stability of sol-gel solution, ormosil coating formulation and coated substrate was also studied using UV-vis spectroscopy and UV-weatherometer to see performance of coating in outdoor application. Thermal behavior of ormosil was characterized using TGA and DSC. Surface morphology and structural characteristics were also characterized using SEM, AFM and FIF-IR-RAS (reflection absorption spectroscopy). Pencil hardness, impact test and bend test were carried out to determine the adhesion, hardness and flexibility of coating. Results show that the coatings were uniform, transparent and crack free. Corrosion resistance and hydrophobicity of coating system with 20H-30H (20-30 wt% HMMM of total resin) of HMMM were found excellent. All the coatings have good resistance to isopropanol, toluene, 3.5 % NaCl and methyl ethyl ketone. However, it degraded in nitric acid solution. UV-vis spectroscopy and UV-weathering suggest that these coatings are stable in sunlight. The gloss retention for 25H coating was found about 83.32% without any visible pit or corrosion product. The coatings are thermally stable upto 325 degrees C and none of coatings show evidence of glass transition temperature. (c) 2007 Elsevier B.V. All rights reserved.

Abstract  Flash setting accelerators are a class of admixtures commonly used for sprayed concrete during tunnel excavation. They allow an immediate set of concrete which can bind to the substrate without dangerous collapses. Such a coating layer prevents the section convergence that is its tendency to squeeze. The early strength development (till 1 h) of the sprayed concrete can be connected to the final set time of cement pastes admixed with the accelerator. The lower is the final set time, the higher should be the early strength. Two main methods are used to project concrete: wet and dry. Today, for safety reasons and to obtain more homogeneous concrete layers, the wet method is becoming more diffused. This technique requires the use of liquid flash setting accelerators which are pumped to a nozzle and immediately projected onto the rock wall. In the European market, two kinds of setting accelerators are mainly available: alkali-rich and alkali-free. Recently, for several reasons, the demand of alkali-free accelerators is growing very rapidly. They are water solutions of aluminium sulphate with a total alkali metal content (expressed as equivalent of Na2O) lower than 1%. In order to develop new and more performing accelerators, several studies are in progress to elucidate their action mechanism and the factors affecting the setting of accelerated concretes. During an experimental study on the setting behaviour of several cement pastes reacting with an alkali-free accelerator, we found a cement showing, as time proceeded, a persistent setting time reduction. We discovered that the effect was connected to the cement exposure to the moisture. A mineralogical investigation performed on this particular cement revealed the presence of hemihydrate as setting regulator. In order to study the interaction between the alkali-free accelerator and this moist aged cement, some morphological (ESEM-FEG), crystal-chemical (XRD), physical-chemical (hydration temperature profile) and chemical (ICP) analyses on cement paste samples were carried out. This study showed a significant setting time reduction of cement paste samples admixed with an alkali-free accelerator when they are composed of a Portland cement containing beta-hemihydrate that was previously exposed to moisture. Such an effect seems to be related to the reduction of the beta-hemihydrate dissolution rate. (c) 2007 Published by Elsevier Ltd.

Abstract  Experiments were performed to study the effects of select chemicals on the mitigation of delayed ettringite formation in Portland cement concrete (PCC) specimens. Specimens were prepared, conditioned and chemically treated with crystal growth inhibitors or waterproofing agents. They were then cured and physical properties were evaluated as a function of curing time. Reaction products were evaluated using scanning electron microscopy and energy dispersive X-ray fluorescence analysis techniques. While the chemicals did not mitigate delayed ettringite formation, the systems did yield large amounts of secondary ettringite of various morphologies. The lack of mitigation of delayed ettringite formation may be attributable to an overabundance of ettringite resulting from intensive conditioning protocol and/or too low a dosage of crystal growth inhibitor or waterproofing agent. Characterisation of the systems revealed some trends in morphological development, for example the samples cured for long times had a preponderance of lamella and laths involved. These and other morphologies observed were consistent with the literature, especially those studies based on scanning electron microscope evaluations of fracture surfaces. Chemical compositions, determined by energy dispersive X-ray fluorescence analysis, regardless of treatment or curing time, were generally quite similar, showing reasonable ratios of calcium: sulfur: aluminium. While delayed ettringite formation mitigation was not achieved, the results demonstrate the usefulness of scanning electron microscopy/energy dispersive X-ray fluorescence analysis examination of fracture surfaces for the evaluation of morphological and chemical features in concrete durability studies.

Abstract  Head and neck cancer can be caused by the occupational contact with cancerogenic substances, which contribute to the formation of cancer. The knowledge about those cancer entities which are frequently found under similar circumstances and working conditions, helps for getting compensation and alternatively for a realistic view when other influences--particularly lifestyle factors like smoking, alcohol and nutrition--have mainly contributed for the origin of the cancer disease. Our knowledge increases and therefore it is helpful from time to time to keep up to the state-of-art of cancer genesis. This article has two parts: part I deals with occupational cancer diseases, which are listed in a decree of the German government and part II deals with the cancer diseases, which could likely be caused by occupational factors according to latest scientific findings and are not yet listed.

Abstract  A method was developed to analyze metals in asbestos (1332214) samples by neutron activation. Samples of asbestos were dried at 100 degrees-C, cooled, and 100 milligram portions were sealed in silica ampules. Standards were also prepared in silica ampules, and both samples and standards were placed in aluminum cans. They were irradiated, weighed, sintered with sodium-peroxide, and dissolved in hydrochloric-acid. Chemical separation was carried out by means of hydroxide precipitation followed by anion exchange, and their radiation products were eluted. A gamma ray spectrometer was also used as a comparison to determine if the standards prepared by milling were different from the standard reference samples. The metals determined were chromium (7440473) (Cr), nickel (7440020), cobalt (7440484) (Co), iron (7439896) (Fe) and scandium (7440202) (Sc). No significant differences were detected in the milled and nonmilled standards. Several types of asbestos, Canadian chrysolite (12001295) and crocidolite (12001284) samples were analyzed using this method. The chrysolite samples had concentrations ranging from 1.8 to 5.0 percent Fe, 120 to 1200 parts per million (ppm) Cr, 39 to 110ppm Co, 550 to 2600ppm Ni, and 4.1 to 12.0ppm Sc. The African crocidolite samples had concentrations ranging from 20 to 26 percent Fe, 0.4 to 0.9ppm Co, and 0.04 to 0.6ppm Sc. The Cr content was less than 20ppm, and the Ni content was less than 100ppm. The authors conclude that these metals can be determined in asbestos samples with good sensitivity by neutron activation.

Abstract  The Doriri Creek (DC) Ni-Pd-Pt prospect was discovered in 1966 in the Papuan Ultramaflc Belt (PUB) in PNG. The DC was interpreted as a hydrothermal Ni accumulation. The DC is located in the southern proximity of Mt Suckling (similar to 180 km SE of Port Moresby), where local intrusive rocks are intermediate to acid dykes and small stocks, within the tec tonized contact zone of the Australian and Woodlark Plates. The active volcanoes of Mount Victory and Waiowa indicate recent thermal activity in the area. The Doriri Creek prospect is the result of episodic hydrothermal fluid flow running through the Doriri prospect, that resulted in Ni concentration of up to 1.55 wt.%, formed by alteration of an ultramafic unit of peridotites/pyroxenites within a Mg-rich gabbronorite envelope. Ni was concentrated in chlorite and serpentine group minerals in addition to Fe oxides, with a minor amount in pentlandite in locally sulfidic samples. Ore mineralogy is also associated with a high phosphorous content as apatite, that concentrates LREE (light rare earth elements). Palladium concentrations are up to 037 ppm. Platinum is present in concentrations up to 0.06 ppm within the ore. The alteration halo associated with Doriri Creek mineralization is similar to 100 m in width. Primary mineralogy comprises pyroxene, olivine and plagioclase, which have been altered extensively to amphibole and chlorite-serpentine group minerals. This halo is characterized by enrichments of U, K and W over background values. Local magnetite concentration is up to similar to 35% of whole rock, which is very pronounced in the sulfide rich area of the system. The top part of the DC system is overprinted by tropical weathering at metric scale, which displays LREE enrichment and positive Ce anomalies. The Papuan Ultramafic Belt is described as a highly prospective ground for hydrothermal Ni systems based on its availability of Ni, active thermal flow engines, and the geologic regional context dominated by mafic rock suites and the presence of carbonate/siliciclastic units. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. RRM CASE STUDY HUMAN CARCINOGEN DYSPNEA TUMOR EXCISION FUSIFORM CELL DIAGNOSIS COMPUTED TOMOGRAPHY HISTOLOGY

Abstract  OBJECTIVES: 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) is a highly toxic persistent environmental contaminant, classified as a human carcinogen affecting any target organ. The mechanism of carcinogenesis by TCDD is unclear as TCDD shows a lack of direct genotoxicity. Experimental studies also support the role of oxidative stress in TCDD neurotoxicity and vascular dysfunction. The aim was to investigate markers of oxidative/nitrosative stress and inflammation using non-invasive methods in subjects who got ill due to severe occupational exposure to TCDD in the years 1965-1968.

METHODS: In 11 TCDD-exposed patients, and 16 controls, the analysis of following oxidative products of lipids, proteins and nucleic acids in plasma, urine and exhaled breath condensate (EBC) was performed: 8-iso-prostaglandin F2α (8-isoprostane), 4-hydroxy-trans-2-nonenale (HNE), malondialdehyde (MDA), o-tyrosine (o-Tyr), 8-hydroxyguanosine (8-OHG), 8-hydroxy-2´-deoxy-guanosine (8-OHdG), 5-hydroxymethyluracil (5-OHMeU). In addition, nitric-oxide-tyrosine (NO-Tyr) and leukotriene (LT) B4, C4, D4, and E4 were detected by liquid chromatography-mass spectrometry/mass spectrometry (LC-ESI-MS/MS). TCDD was measured by HRGC/HRMS, body lipid content by densitometry. Single-photon emission spectrometry (SPECT) of the brain was performed and compared with the findings of the patients in 2008.

RESULTS: Mean TCDD plasma level in 2010 was 175 ± 162 pg/g lipids (population level about 2 pg/g), total TCDD content in the body 5.16 ± 4.62 mg. Reduction of cerebral blood flow in SPECT progressed in 8 patients, finding was stable in 2 subjects, and improvement occurred in 1 patient. In the EBC, 10 from 12 markers (all except LT D4 and LT E4), were significantly increased in the patients (p<0.05). In the urine, 7 markers were significantly higher than in the controls (p<0.05): 8-isoprostane, MDA, HNE, LT C4, LT E4, o-Tyr and NO-Tyr. In plasma, only NO-Tyr and 8-OHG were elevated (p<0.05).

CONCLUSION: NO-Tyr was increased in all matrices in dioxin-exposed patients. EBC is not limited to lung disorders as the markers of oxidative stress and inflammation were elevated in EBC of patients with normal lung functions. TCDD-induced oxidative stress and inflammation markers can be detected non-invasively in the EBC and urine in the follow-up of the highly-exposed patients. Their prognostic value, however, needs to be elucidated.

Abstract  With regard to measuring nitrous oxide (N(2)O) emissions from biological sources, there are three most widely adopted methods that use gas chromatograph with an electron capture detector (GC-ECD). They use: (a) nitrogen (N(2)) as the carrier gas (DN); (b) ascarite as a carbon dioxide (CO(2)) trap with DN (DN-Ascarite); and (c) a mixture gas of argon and methane as the carrier (AM). Additional methods that use either a mixture of argon and methane (or of CO(2) and N(2)) as a make-up gas with the carrier nitrogen or soda lime (or ascarite) as a CO(2) trap with the carrier helium have also been adopted in a few studies. To test the hypothesis that the use of DN sometimes considerably biases measurements of N(2)O emissions from plants, soils or soil-plant systems, experiments were conducted involving DN, AM and DN-Ascarite. When using DN, a significant relationship appeared between CO(2) concentrations and the apparent N(2)O concentrations in air samples. The use of DN led to significantly overestimated N(2)O emissions from detached fresh plants in static chamber enclosures. Meanwhile, comparably lower emissions were found when using either the DN-Ascarite or AM methods. When an N (2)O flux (from a soil or a soil-plant system), measured by DN in combination with sampling from the enclosure of a static opaque chamber, was greater than 200 mu g N m(-2) h(-1), no significant difference was found between DN and DN-Ascarite. When the DN-measured fluxes were within the ranges of <-30, -30-0, 0-30, 30-100 and 100-200 mu g N m(-2) h(-1), significant differences that amounted to -72, -22, 5, 38 and 64 mu g N m(-2) h(-1), respectively, appeared in comparison to DN-Ascarite. As a result, the DN measurements in rice-wheat and vegetable fields overestimated both annual total N(2)O emissions (by 7-62%, p < 0.05) and direct emission factors for applied nitrogen (by 6-65%). These results suggest the necessity of reassessing the available data determined from DN measurements before they are applied to inventory estimation. Further studies are required to explore appropriate approaches for the necessary reassessment. Our results also imply that the DN method should not be adopted for measuring N(2)O emissions from weak sources (e.g., with intensities less than 200 mu g N m(-2) h(-1)). In addition, we especially do not recommend the use of DN to simultaneously measure N(2)O and CO(2) with the same ECD.

Abstract  Asbestos containing gaskets have always been used to seal connections of the aluminum tapping crucibles cast iron tubes used in the pot lines at Albras. This was the most durable and cheapest material available for supporting the high temperatures and for making good seals. However, due to industrial hygiene concerns about the carcinogenic nature of asbestos, which demand special care to use and dispose of, the decision was taken at Albras to look for an alternative material to use for this and other applications. Specifically, for tapping crucibles a clay-based material has been developed with a internal metallic support which improves its resilience. An aspect of the development process was optimizing the curing time of the clay.

Abstract  Certain Louisiana cancer rates are higher than the national averages. This review evaluates the existing epidemiologic literature pertaining to risk factors for cancer in Louisiana. Population-based case-control studies have identified smoking as the most important contributor to lung cancer in Louisiana. Nutritional factors have been found to impart a modest increase in lung, pancreas, and stomach cancer risk. Occupational epidemiologic studies have revealed exposure to asbestos in the cement, shipbuilding, and related industries as a significant risk factor for mesothelioma and lung cancer. Sugarcane farming has been found to increase the risk of lung cancer among sugarcane farmers who smoke, and the risk of mesothelioma among sugarcane farmers in general. Occupations with exposure to microwave and radio frequency electromagnetic radiation have been associated with an increased risk of brain cancer. An increased risk of laryngeal cancer has been observed among workers exposed to sulfuric acid at a Baton Rouge isopropyl alcohol plant. Except for the laryngeal cancer finding, data from occupational cohort studies of refinery/chemical workers revealed no significant excess in cancer of all sites, cancer of the lung, or any other cancer. Relevant epidemiologic data also revealed no increased cancer risk associated with potential exposures to industrial emissions among residents in communities adjacent to petrochemical facilities.

Abstract  Cases of nonasbestos related mesothelioma were reviewed. Reported cases of spontaneously occurring mesothelioma included mesotheliomas of the tunica vaginalis testis, pericardium, anterior mediastinum, and myocardium. Significant numbers of nonasbestos forms of mesothelioma were induced in animal studies in response to exposures to C-type viruses, MC29 avian leukosis virus, the SV40 virus, ethylene-oxide, ethylene-dibromide, polymethane, diatomaceous-earth, sinapaldehyde, l-nitroso-5,6-dihydrouracil, sterigmatocystin, methyl-(acetoxymethyl)nitrosamine, N-methyl-N-nitrosourea, N-methyl-N-nitrosourethane, polysilicone plastics, diethylstilbestrol, nickel powder, beryllium and other heavy metals, glass fibers, aluminum-oxide, tremolite, attapulgite, dawsonite, silicone-carbide, potassium-titanate, erionite/zeolite, and ionizing radiation. Reports of case studies in humans indicated erionite/zeolite, ionizing radiation, and long term inflammation as possible causes of nonasbestos mesothelioma.

Abstract  The aim of this study was to determine the inorganic filler fractions and sizes of commercially alginates. The inorganic particles volumetric fractions of five alginates - Jeltrate(J), Jeltrate Plus(JP), Jeltrate Chromatic Ortho(JC), Hydrogum(H) and Ezact Krom(E) were accessed by weighing a previously determined mass of each material in water before and after burning samples at 450 degrees C for 3 hours. Unsettled materials were soaked in acetone and chloroform and sputter-coated with gold for SEM evaluation of fillers' morphology and size. The results for the volumetric inorganic particle content were (%): J - 48.33, JP - 48.33, JC - 33.79, H - 37.55 and E - 40.55. The fillers presented a circular appearance with helical form and various perforations. Hydrogum fillers looked like cylindrical, perforated sticks. The mean values for fillers size were (mu m): J - 12.91, JP - 13.67, JC - 13.44, E - 14.59 and H - 9 (diameter), 8.81 (length). The results of this study revealed differences in filler characteristics that could lead to different results when testing mechanical properties.

Abstract  Whole-rock geochemical and Sr, Nd and Pb isotope data are presented for the Harrat Al-Madinah volcanic field, in the north western part of the Arabian plate, aiming to understand their origin and the composition of their mantle source. This area is an active volcanic field characterized by the occurrence of two historic eruptions approximately in 641 and 1256 A.D. Field investigation of the main volcanic landforms indicates dominantly monogenetic strombolian eruptions, in addition to local phreatomagmatic eruption style. The lavas consist mainly of alkali olivine basalt, olivine transitional basalt, and hawaiite with ocean island basalt (OIB)-like characteristics. Evolved rocks, represented by mugearites, benmoreites, and trachytes, occur mainly as domes, tuff cones and occasionally as lava flows. Chemical variations in the evolved rocks indicated their evolution by low pressure crystal fractionation of olivine, plagioclase, clinopyroxene, and Fe-Ti oxides from the relatively primitive basalts. The isotopic compositions of Nd-143/Nd-144 (0.512954-0.512995), Sr-87/Sr-86 (0.702899 to-0.702977) and Pb (Pb-206/Pb-204 = 18.5515-18.7446, Pb-207/Pb-204 = 15.5120-15.5222, Pb-208/Pb-204 = 38.1347-38.4468), show restricted variations suggesting only minor crustal contamination. They defined an array consistent with mixing of two geochemically distinct components of depleted MORB-mantle (DMM) and high U-238/Pb-204 ratio (HIMU). The variations in Tb/Yb, La/Yb and Sm/Yb ratios in the relatively primitive basalts (MgO > 6 wt.%) indicated garnet peridotite source. However, the positive Nb, Sr, Ba and Ti anomalies in the primitive mantle-normalized incompatible element patterns and the significant variation between Zr/Nb vs. Ce/Y and La/Yb vs. Yb suggest contribution of an amphibole-bearing spinel lherzolite source. Moreover, the negative correlations between SiO2 vs. Sr-87/Sr-86 and Th vs. Nd-143/Nd-144 are interpreted as an indication of mixing melts derived from two end-members; one is garnet bearing asthenospheric source with OIB characteristic and the other is amphibole-bearing spinet lherzolite. The Harrat Al-Madinah volcanic field occurs near the Red Sea Rift System and its origin reflects a strong lithospheric control on the loci of partial melting. The dominantly NNW alignment patterns of the volcanoes, which is similar to the regional Red Sea trend, may suggest that the magmas were produced by decompression partial melting triggered by lithospheric extension related to the Red Rift. (C) 2011 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Abstract  BACKGROUND: A major French chlorine chemical plant (chlor-alkali process with diaphragm cell and manufacturing of organochlorine chemicals) has used or produced known or suspected carcinogenic compounds.

METHODS: A cohort study, based on the plant occupational health service and the regional cancer registry, analyzed the standardized incidence ratios of malignant tumors for the period 1979-2002. Individual exposures were estimated from workers' occupational histories in a dual division of jobs into 9 sectors and 115 workshops with known exposures.

RESULTS: Men (2,742) were followed, corresponding to 52,794 person-years. Primary tumors (304) were observed for 290 expected cases, a non-significant 5% excess. A significant excess was found of pleural mesothelioma and bladder cancer in employees hired before 1964.

CONCLUSION: Excesses of mesothelioma and bladder cancer were found, whereas there was no excess of hematopoietic cancers despite high benzene and dioxin exposures. Surprisingly, mesothelioma cases did not include workers who were the most exposed to asbestos.

Abstract  Uric acid crystals, the causative agent of gout, have recently gained widespread attention due to their role as a natural endogenous adjuvant. Uric acid crystals, first sensed extracellularly by membrane lipid alterations, are internalized and subsequently activate the NLRP3 inflammasome. Currently, various aspects of this particular novel pathway are poorly defined. This short review will focus on some recent discoveries regarding this simple crystalline structure and address areas requiring further investigation. The fact that uric acid crystals activate innate host defense mechanisms, triggering robust inflammation and immune activation, may lead to engineering potent adjuvants for future vaccines. Furthermore, the elucidation of uric acid's mechanism of inflammation may lay the foundation for other solid inflammatory structures such as silica, asbestos, and alum.

Abstract  The role of occupational risk factors in oral and pharyngeal cancer is not well known and is possibly underestimated. This quantitative review summarizes epidemiological findings on exposure to asbestos, polycyclic aromatic hydrocarbons and solvents, and cancers of the oral cavity and pharynx.

A systematic literature search was performed. We analyzed 63 publications: 8 from case-control studies and 55 from cohort studies. For agents with at least five available studies with homogenous exposure, a series of meta-analyses was conducted to provide quantitative pooled estimates of risks, using random effect models.

Exposure to asbestos (meta-RR 1.25; 95% CI 1.10-1.42) and to polycyclic aromatic hydrocarbons (meta-RR 1.14; 95% CI 1.02-1.28) was found to be associated with oral and pharyngeal cancer risk. On the other hand, no association was found with exposure to solvents in general (meta-RR 0.98; 95% CI 0.77-1.23) but the strong heterogeneity between studies suggested differences in exposures. The small number of studies with homogeneous exposure did not allow meta-analyses for specific solvents.

Future investigations should overcome common weaknesses of past studies, in terms of sample size, characterization of exposure, and classification of cancer sites.

Abstract  The action of different concentrations of sodium chloride, benzocaine and clove oil in the survival of fingerling and juvenile tilapia (Oreochromis niloticus), chitralada lineage, was tested during 5 hours for transportation. A total of 1350 fingerlings were used (weight 9.74 +/- 0.04 g and length 6.79 +/- 0.01 cm) and 270 juveniles (average weight 29.6 +/- 0.06 g and length 11.52 +/- 0.01 cm). The fish were maintained without food for 24 hours in four 500L asbestos boxes with constant aeration. Subsequently, the fish were distributed in 54 5 L plastic bags and maintained in a solution of sodium chloride at a concentration of (0; 4; 8 g/L), benzocaine (0; 20; 40 mg/L) and clove oil (0; 2; 5 mg/L). A randomized block experimental design was used with three replications, in multi-factorial arrangements, with three factors: substances, fish and different concentrations for each substance used. Dissolved oxygen, temperature, pH, salinity and ammonia were measured at the beginning of the experiment and the fish glucose at the end of the experiment. The largest glucose levels were detected in the juveniles maintained in water with clove oil and sodium chloride. Significant differences were not observed in the survival among types of fish and substances. However, the doses used of sodium chloride and benzocaine caused significant differences in the survival rate. There was low fingerling survival with 0 g/L of sodium chloride that differed from the doses 4 and 8 g/L. The clove oil presented similar results at all the different doses and all the substances on the glucose rates. Survival was satisfactory at the end of the experiment, with a general average of 97.26%, showing that the three substances can be used to transport fingerlings and juveniles during 5 hours. Sodium chloride is recommended because it was the most cost-effective.