Rapid Increase In Concentration Research Articles

A regional interpretation of rules and good practice for greenhouse accounting: northern Australian savanna systems

Land-use change, particularly clearing of forests for agriculture, has contributed significantly to the observed rise in atmospheric carbon dioxide concentration. Concern about the impacts on climate has led to efforts to monitor and curtail the rapid increase in concentrations of carbon dioxide and other greenhouse gases in the atmosphere. Internationally, much of the current focus is on the Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC). Although electing to not ratify the Protocol, Australia, as a party to the UNFCCC, reports on national greenhouse gas emissions, trends in emissions and abatement measures. In this paper we review the complex accounting rules for human activities affecting greenhouse gas fluxes in the terrestrial biosphere and explore implications and potential opportunities for managing carbon in the savanna ecosystems of northern Australia. Savannas in Australia are managed for grazing as well as for cultural and environmental values against a background of extreme climate variability and disturbance, notably fire. Methane from livestock and non-CO2 emissions from burning are important components of the total greenhouse gas emissions associated with management of savannas. International developments in carbon accounting for the terrestrial biosphere bring a requirement for better attribution of change in carbon stocks and more detailed and spatially explicit data on such characteristics of savanna ecosystems as fire regimes, production and type of fuel for burning, drivers of woody encroachment, rates of woody regrowth, stocking rates and grazing impacts. The benefits of improved biophysical information and of understanding the impacts on ecosystem function of natural factors and management options will extend beyond greenhouse accounting to better land management for multiple objectives.

The Roles of Corporatization and Stock Market Listing in Reforming China’s State Industry

Summary This article provides an overview of China’s on-going efforts to reform its industrial state-owned enterprises (SOEs) through corporatization and stock market listing, and assesses the effects on the performance of these SOEs. It highlights changes, though limited, in both ownership pattern and corporate governance on the one hand, and rapid increase in concentration on the other as a result of these reform measures. It also explores the reasons why these changes have failed to significantly improve the performance of the SOEs, but have nevertheless paved the way for more complete privatization. The practical implications of these findings are also discussed.

Thunderstorm asthma.

Thunderstorms have often been linked to epidemics of asthma, especially during the grass flowering season; however, the precise mechanisms explaining this phenomenon are unknown. Evidence of high respirable allergen loadings in the air associated with specific meteorologic events combined with an analysis of pollen physiology suggests that rupture of airborne pollen can occur. Strong downdrafts and dry, cold outflows distinguish thunderstorm rain from frontal rain. The weather system of a mature thunderstorm likely entrains grass pollen into the cloud base, where pollen rupture would be enhanced, then transports the respirable-sized fragments of pollen debris to ground level where outflows distribute them ahead of the rain. The conditions occurring at the onset of a thunderstorm might expose susceptible people to a rapid increase in concentrations of pollen allergens in the air that can readily deposit in the lower airways and initiate asthmatic reactions.

Interaction of dimethyl methylphosphonate with Nafion in acid and cation modifications

Sorption kinetics and sorption isotherms have been determined for dimethyl methylphosphonate, DMMP, in a perfluoroionomer, Nafion™, in the acid form and as calcium and ferric salts. Nafion is a phase segregated polymer with a fluorocarbon main chain and sulfonic acid terminated fluoroether side chain comprising 33 wt% of the polymer. DMMP swells only the fluoroether region. Under immersion conditions, equilibrium solubilities for all three forms are essentially equal, averaging about 130 wt%. Kinetics are non-Fickian, dominated by relaxation effects, with calcium much slower than the acid form of Nafion, and ferric slower still. Analysis with the Joshi–Astarita model of relaxation coupled diffusion indicates that the effect of cation modification is a more than 200-fold decrease in both diffusion coefficient and relaxation rate. Vapor sorption kinetics is also non-Fickian and dominated by relaxation, frequently involving a series of steps or several maxima at high vapor activity. Additionally, kinetics and, to a lesser extent equilibrium solubilities, are affected by sample history and conditions of sample exposure. The sorption isotherm, for acid Nafion exhibits a rapid concentration increase at vapor activities below 0.2, a low slope at intermediate activities and a rapid increase above activity 0.8. Isotherms for salt modifications are similar but with even lower slope at intermediate activities. Effective diffusion coefficients for acid Nafion, calculated from boundary layer corrected steady state permeabilities combined with the sorption isotherm, exhibit a pronounced rise at a volume fraction of 0.6. A transition in NMR solvent self-diffusion coefficients attributed to the emergence of a new phase segregated structure is reported at the same concentration. When effective diffusion coefficients are converted to solvent self-diffusion coefficients, the values are 30-fold lower than NMR values at low concentrations, taken as a measure of tortuosity, but closely approach NMR values above the transition. The prominence of relaxation controlled sorption kinetics and high degree of tortuosity below the transition suggest that Nafion is a disordered structure of small interspersed fluoroether and fluorocarbon regions, whereas the occurrence of discrete relaxation events, mainly at high activities, is probably associated with larger scale reorganization of the partially coalesced phases above the transition.

The influence of immobilization of Pseudomonas sp. 2 on optical detection of polychlorinated biphenyls

The cells Pseudomonas sp. 2 were immobilized on porous glass surface (S), encapsulated into alginate beads (A), encapsulated into alginate beads coated with a silica layer (AC) and entrapped into silica gel (C). The silica layer thickness of 2.5 μm was prepared from prepolymerized tetramethoxysilane by dipping of the alginate beads. The production of stable yellow intermediates of biodegradation of PCBs, congeners with three chlorine atoms, was used for the detection of commercial mixture of PCBs, Delor 103. In the initial stage of biodegradation of Delor 103, the highest and the most rapid increase of concentration of yellow color was observed in the case of biodegradation with AC but the selectivity of the detection method was decreased by the simultaneous production of orange compounds. The necessary conditions for production of orange intermediates were concentration of biphenyl or PCBs with biphenyl 5 g/l together with 2–6 vol.% of methanol. Trihydroxyphenyl pyridine, phenyl pyridine, dimethylhydrazide of benzoic acid, pyridine carboxylic acid and trimethylindane were identified in the lyophilized solution of the orange compounds. The metabolic pathways of the creation of orange compounds are unknown and for that reason, utilization of these metabolites for optical detection of PCBs needs further research.

Bioassay for the rapid detection of bacteriocins in fermentation broth

A bioassay for the rapid detection of bacteriocins by detecting efflux of K+ ions from a bacteriocin-sensitive indicator strain was developed. There was a rapid increase in concentration of K+ in the medium from approximately 1.6 to 9.5 mM when the crude bacteriocin was added to the sensitive strain. A bacteriocin activity of 8.25 AU ml−1 produced the lowest detectable concentration of K+ (0.179 mM) and the smallest inhibition zone (0.4 mm). The smallest cell dry mass of the indicator strain capable of releasing a detectable level of K+ (0.102 mM) was 0.76 mg. Detection of the bacteriocin by measuring the efflux of K+ compares well with the conventional agar well diffusion assay. Low activities of bacteriocin and low amounts of the sensitive indicator strain biomass can be used with this bioassay.

Changes in hemodynamic variables and catecholamine levels after rapid increase in sevoflurane or isoflurane concentration with or without nitrous oxide under endotracheal intubation.

Rapid increases in concentrations of isoflurane and desflurane in oxygen have been shown to increase sympathetic activity. The aim of this study was to determine whether concomitant administration of nitrous oxide would reduce these sympathomimetic effects of volatile anesthetics. Eighty healthy patients in whom the trachea was intubated and mechanically ventilated were given 15 min of anesthesia with either N(2)O (67%)-O(2)-sevoflurane (GOS), O(2)-sevoflurane (OS), N(2)O (67%)-O(2)-isoflurane (GOI), or O(2)-isoflurane (OI) (n = 20 per group). The inspired concentration of sevoflurane was 0.85% (0.5 minimum alveolar concentration [MAC]), and that of isoflurane was 0.6% (0.5 MAC). Fifteen minutes after endotracheal intubation, baseline and arterial blood sample data were obtained. Immediately after that, a sudden administration of 2.9 MAC volatile anesthetics was performed. Systolic and diastolic arterial pressures, heart rate, and end-tidal carbon dioxide concentration were obtained at 0.5, 1, 1.5, 2, 3, 4, and 5 min after that. To measure catecholamine levels, arterial blood samples were obtained 2 and 5 min after the trial started. Except for the OI group, systolic and diastolic arterial pressure progressively decreased after the abrupt increase in the concentration of volatile anesthetics. Except for the OS group, the heart rate increased after the abrupt increase in the concentration of volatile anesthetics. In the OI group, the end-tidal concentration of carbon dioxide increased at 0.5 and 1 min, suggesting that a slight hyperdynamic state occurred. However, it decreased progressively after the abrupt increase in volatile anesthetic concentration in the other groups. Plasma norepinephrine levels increased progressively in all groups. Even if nitrous oxide was added to isoflurane or sevoflurane, the increase in heart rate could not be avoided. Contrary to previous reports, severe hyperdynamic circulation was not observed after a rapid increase in isoflurane concentration.

Nutrient Availability and Changes in Microbial Biomass Of Organic Amendments During Field Incubation

Field evaluation of release and availability of nutrients and potentially toxic elements from composts is necessary to estimate their nutrient contribution to crops, potential effect on soil and environmental quality. A biosolids (BSD), a yard waste (YW), and a West Palm Beach cocompost (WPCC) were incubated under field conditions in a citrus grove on an Oldsmar fine sandy soil (sandy, siliceous, hyperthermic Alfic Arenic Haplaquods). The incubation columns and the soil underneath each column were sampled on 0, 240, and 360 days after incubation and analyzed for KCl extractable NH4-N and NO3-N, 0.5 M NaHCO3 extractable P, and Mehlich 3 extractable K, Fe, Mn, Zn, Cu, and microbial biomass. The total concentration and extractable proportion of each element greatly varied among the three organic amendments. Approximately 34-73% of K, 1-14% of Fe, 7-68% of Zn, 7-47% of Mn, and 2-34% of Cu in the three organic amendments were extractable by the Mehlich 3 reagent at the beginning of incubation. Incubation of these amendments under field conditions for a period of 1 yr increased the availability of N, P, K, and several micronutrients including Fe, Cu, Zn, and Mn. Microbial biomass-C and -P were markedly increased during the field incubation. However, the BSD, containing high total C and other nutrients, produced less microbial biomass-C than the two composts. The rapid increase in concentrations of available metals including Cu, Zn, and Mn in the BSD during the incubation may have adverse effects on microbial biomass growth and proliferation in this compost. A combination of BSD and YW improved conditions for the microbial biomass growth as evidenced by the increase in microbial biomass C and P of this combination during the course of incubation.

Climate change and greenhouse gases

Infrared (IR) active gases, principally water vapor (H2O), carbon dioxide (CO2), and ozone (O3), naturally present in the Earth's atmosphere, absorb thermal IR radiation emitted by the Earth's surface and atmosphere. The atmosphere is warmed by this mechanism and, in turn, emits IR radiation, with a significant portion of this energy acting to warm the surface and the lower atmosphere. As a consequence the average surface air temperature of the Earth is about 30°C higher than it would be without atmospheric absorption and reradiation of IR energy [Kellogg, 1996; Peixoto and Oort, 1992; Henderson‐Sellers and Robinson, 1986].This phenomenon is popularly known as the “greenhouse effect,” and the IR active gases responsible for the effect are likewise referred to as “greenhouse gases.” The rapid increase in concentrations of greenhouse gases since the industrial period began has given rise to concern over potential resultant climate changes.

Comparison of the myocardial effects of desflurane and isoflurane in healthy patients: assessment by continuous oesophageal aortic blood flow echo-Doppler

Experimentally, desflurane causes a moderate positive inotropic effect and a transient increase in arterial pressure with rapid increases in concentration compared with isoflurane. We used a continuous oesophageal aortic blood flow echo Doppler device to study the myocardial effects of equi-anaesthetic concentrations of isoflurane and desflurane in 32 healthy patients undergoing superficial surgery. After induction of anaesthesia with midazolam, etomidate and fentanyl general anaesthesia was maintained in 16 patients with 0.6% end-expired concentration of isoflurane and in 16 patients with 3% end expired concentration of desflurane. Isoflurane induced a rapid decrease in aortic blood flow (ABF) which remained almost stable whereas desflurane induced an early, moderate and transient increase in ABF (1 min after introduction of the halogenated agent, mean ABF was 107 (SD 3)% in the desflurane group vs 95 (9)% in isoflurane group compared with control values before introduction of the inhalation agent; P = 0.005), followed by a marked secondary decrease in ABF. The maximal decrease in ABF reached 71 (15)% of its initial value in the desflurane group compared with 80 (14)% in the isoflurane group (ns). Neither agent caused significant changes in other variables except for PE'CO2 which decreased in both groups. Continuous ABF echo-Doppler monitoring demonstrated an early transient positive inotropic effect of desflurane.

Behaviour and Impact of Cow Slurry Beneath a Storage Lagoon: 1. Groundwater Contamination 1975–1982

The chemical and biological composition of groundwater sampled from a 76 m deep borehole situated 80 m from an unlined, earth-banked lagoon excavated in Upper Chalk and continuously used to store liquid cow manure was regularly monitored from August 1975 to January 1982 for signs of pollution. The lagoon became self-sealing 3 months after the start of filling in 1975, but was further enlarged and re-filled in autumn 1976, and emptied by dragline in September 1978 and 1980. No significant changes in groundwater composition were detected in the period August 1975 to December 1978. In January 1979, significant numbers of Escherichia coli and a large, rapid increase in concentrations of ammonium-nitrogen (NH4-N), phosphorus (P), potassium (K), sodium (Na), chloride (Cl) and sulphate (SO4) were detected in the groundwater. Nutrient concentrations fluctuated at elevated levels throughout 1979 but decreased during 1980. Additional bacterial and chemical (NH4-N, P and K) contamination was recorded in January 1981 and subsequent months. The contamination was considered to have occurred as a result of fissure flow through the unsaturated zone of the Upper Chalk following repeated disruption of the self-sealing layer during emptying of the lagoon by dragline in September 1978 and 1980. The results indicate that unlined, earth-banked slurry storage lagoons need to be carefully managed to avoid biological and chemical pollution of Chalk aquifers.

Effect of Oxytocin on Concentrations of Prostaglandin H Synthase-2 mRNA in Ovine Endometrial Tissue in Vivo

Oxytocin is an acute stimulus of prostaglandin (PG) F2α secretion from the ovine uterine endometrium. The high level of PGF2α secretion induced by oxytocin and the short half-life of the prostaglandin synthase-2 (PGHS-2) enzyme implies that synthesis of PGHS-2 may be essential at this time. The objective of this study was to determine if the increase in PGF2α secretion induced by oxytocin is associated with an increase in PGHS-2 mRNA. In experiment 1, oxytocin induced a rapid increase in serum concentration of 13,14-dihydro-15-keto-prostaglandin F2α (the stable metabolite of PGF2α; PGFM) that was detected within 7.5 min (P < 0.05) and peaked at 25 min post injection. This was associated with an unusually rapid increase in the concentration of PGHS-2 mRNA at 25 min post oxytocin injection (P < 0.05). Endometrial concentrations of PGHS-2 mRNA returned to basal levels at 90 min post injection. Experiment 2 was conducted to further characterize the time course of induction of PGHS-2 mRNA following oxytocin administration. Oxytocin induced a rapid increase in serum concentrations of PGFM. As in experiment 1, an increase in concentrations of PGHS-2 mRNA was detected at 25 min after oxytocin (P = 0.06). Concentrations of PGHS-2 mRNA were intermediate at 40 min and returned to basal levels at 60 min post injection. Thus, there is a rapid increase in endometrial concentrations of PGHS-2 mRNA following oxytocin stimulation of PGF2α secretion. This increase in PGHS-2 mRNA may be required to maintain PGHS-2 enzyme levels during pulsatile secretion of PGF2α at luteolysis.

Effect of oxytocin on concentrations of prostaglandin H synthase-2 mRNA in ovine endometrial tissue in vivo.

Oxytocin is an acute stimulus of prostaglandin (PG) F2alpha secretion from the ovine uterine endometrium. The high level of PGF2alpha secretion induced by oxytocin and the short half-life of the prostaglandin synthase-2 (PGHS-2) enzyme implies that synthesis of PGHS-2 may be essential at this time. The objective of this study was to determine if the increase in PGF2alpha secretion induced by oxytocin is associated with an increase in PGHS-2 mRNA. In experiment 1, oxytocin induced a rapid increase in serum concentration of 13,14-dihydro-15-keto-prostaglandin F2alpha (the stable metabolite of PGF2alpha; PGFM) that was detected within 7.5 min (P < 0.05) and peaked at 25 min post injection. This was associated with an unusually rapid increase in the concentration of PGHS-2 mRNA at 25 min post oxytocin injection (P < 0.05). Endometrial concentrations of PGHS-2 mRNA returned to basal levels at 90 min post injection. Experiment 2 was conducted to further characterize the time course of induction of PGHS-2 mRNA following oxytocin administration. Oxytocin induced a rapid increase in serum concentrations of PGFM. As in experiment 1, an increase in concentrations of PGHS-2 mRNA was detected at 25 min after oxytocin (P = 0.06). Concentrations of PGHS-2 mRNA were intermediate at 40 min and returned to basal levels at 60 min post injection. Thus, there is a rapid increase in endometrial concentrations of PGHS-2 mRNA following oxytocin stimulation of PGF2alpha secretion. This increase in PGHS-2 mRNA may be required to maintain PGHS-2 enzyme levels during pulsatile secretion of PGF2alpha at luteolysis.

Solid-State Characterization of Paclitaxel

□ The purpose of this work was to characterize the solid-state properties of anhydrous paclitaxel and paclitaxel dihydrate. Paclitaxel I (anhydrous) was suspended in water for 24 h to convert it to paclitaxel·2H2O. Both forms were analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). X-ray powder diffraction (XRPD) patterns were obtained at 25, 100, and 195 °C. Dissolution profiles of both forms were obtained in water at 37 °C over 20 h. DSC of paclitaxel·2H2O showed two endothermic peaks below 100 °C, corresponding to dehydration. The resulting solid phase was termed “dehydrated paclitaxel·2H2O”. At 168 °C, a solid−solid transition was observed in which dehydrated paclitaxel·2H2O was converted to a semicrystalline material called “paclitaxel I/am”. The solid−solid transition was followed by melting at 220 °C. TGA of paclitaxel·2H2O showed a corresponding biphasic weight loss below 100 °C, which was equivalent to the weight of 2 mol of water. DSC of paclitaxel I showed no transitions before melting at 220 °C, and no weight loss was observed by TGA. Quenching of paclitaxel I from the melt produced amorphous paclitaxel with a glass transition at 152 °C. XRPD confirmed that paclitaxel I, paclitaxel·2H2O, and dehydrated paclitaxel·2H2O had different crystal structures. The X-ray patterns of paclitaxel I and paclitaxel I/am were similar, however the two forms of paclitaxel did not behave identically when analyzed by DSC. The bulk dissolution studies with paclitaxel I showed a rapid increase in concentration to 3,μg/mL in 4 h, which decreased to 1,μg/mL after 12 h, corresponding to the solubility of paclitaxel·2H2O. The solubility of paclitaxel·2H2O was 1,μg/mL The data demonstrate the existence of a dihydrate form of paclitaxel that is the stable form in equilibrium with water at 37 °C but which dehydrates at temperatures >45 °C.

Delivery of microbial indicator organisms to coastal waters from catchment sources

The introduction of ultraviolet disinfection of sewage effluent in Jersey has served to focus attention on other sources of faecal pollution responsible for subsequent compliance failures in coastal water quality in St Aubin's Bay. Studies of microbial concentrations (total coliforms, faecal coliforms and faecal streptococci) in streams draining to the bay showed concentrations to be elevated by an order of magnitude or more following rainfall. Detailed monitoring of indicator organisms during hydrograph events showed rapid increases in concentration with flow associated with the rising limb of the hydrograph and transport of suspended solids. Microbial budget estimates suggested that between 42 and 97% of microbial delivery was associated with high flows, which account for just 20% of the total discharge. Budgets also revealed the relative importance of different catchment inputs, revealing the low bacterial input associated with UV treated effluent which provided 48% of the total volume discharged to the bay. Implications for water quality standards are discussed with reference to catchment management planning.

Delivery of microbial indicator organisms to coastal waters from catchment sources

The introduction of ultraviolet disinfection of sewage effluent in Jersey has served to focus attention on other sources of faecal pollution responsible for subsequent compliance failures in coastal water quality in St Aubin's Bay. Studies of microbial concentrations (total coliforms, faecal coliforms and faecal streptococci) in streams draining to the bay showed concentrations to be elevated by an order of magnitude or more following rainfall. Detailed monitoring of indicator organisms during hydrograph events showed rapid increases in concentration with flow associated with the rising limb of the hydrograph and transport of suspended solids. Microbial budget estimates suggested that between 42 and 97% of microbial delivery was associated with high flows, which account for just 20% of the total discharge. Budgets also revealed the relative importance of different catchment inputs, revealing the low bacterial input associated with LTV treated effluent which provided 48% of the total volume discharged to the bay. Implications for water quality standards are discussed with reference to catchment management planning.

Pharmacokinetics of Parenteral 13-cis-Retinoic Acid Formulations in Rats

AbstractThe pharmacokinetics of three 13-cis-retinoic acid formulations were studied after intraperitoneal (ip) administration to rats. Rats were given iv injections of 2.5mg of 13-cis-retinoic acid per 360g of body weight; the drug was administered as an alkaline solution, suspended in com oil, or as a mixture with polysorbate 80. The alkaline solution was also given intravenously (iv) via the tail vein as a control. The mean elimination rate constant, calculated from data from iv administration, was 0.72 ± 0.088 h−1 (r = 0.988). The peak concentration in plasma and the time to reach this maximum were 14 mg/L and 0.5 h, 22 mg/L and ± h, and 10 mg/L and 1h for the drug administered as an alkaline solution, suspended in corn oil, and as a mixture with polysorbate 80, respectively. The areas under the concentration–time curve (concentration in plasma versus time) were 34.9 ± 8.78mg • h/L for the iv dose and 34.1 ± 9.97, 62.4 ± 32.3, and 25.9 ± 12.0mg • h/L for the ip doses of alkaline solution, suspension in oil, and mixture with polysorbate 80, respectively. Because of the rapid increase of concentration in plasma, which is identical to that of the ip profile, and the ease of its handling and preparation, the ip administered alkaline solution is the preferable formulation.

Transport of Naturally Occurring Dissolved Organic Carbon in Laboratory Columns Containing Aquifer Material

AbstractThe subsurface transport of ionic and nonionic pollutants may be strongly impacted by the movement of naturally occurring dissolved organic carbon (DOC) in aquifers. Thus, the adsorption, desorption, and transport of DOC in laboratory columns containing well‐packed aquifer material was investigated. Data showed that the breakthrough of DOC from aquifer columns was the result of complex adsorption reactions between DOC and the aquifer material. Breakthrough curves (BTCs) of the DOC were characterized by an initial rapid concentration increase followed by extended tailing to long times. The extensive tailing of the BTCs was attributed primarily to the slow adsorption kinetics of DOC to the aquifer material and the nonlinear nature of the adsorption isotherm. Independent experiments suggested that the size exclusion of DOC from aquifer pores was negligible. The time required to saturate the aquifer material with organic C was dependent on the influent DOC concentration, with lower organic influent levels requiring longer pulse durations to fully saturate the aquifer sediment with organic C. Hydrophobic constituents of the DOC were preferentially adsorbed while hydrophilic components were rapidly transported through the aquifer columns. Spectral analysis (light absorbance at 260 nm) of the column effluents confirmed that the composition of the mobile organic C changed during the breakthrough of DOC. Data from this investigation demonstrate that DOC can be mobile in soil systems, and emphasizes the need to evaluate the cotransport of pollutants by DOC.

Stimulation of TGF-β1 mRNA concentration in mouse skin treated with benzo[a]pyrene

Topical application of benzo[a]pyrene (B[a]P) at dose rates of 32 or 64 micrograms/week to the dorsal skin of female Swiss (ICR) mice resulted in a marked and rapid increase in concentration of RNA for transforming growth factor beta 1 (TGF-beta 1) in epidermis. Two RNA species 1.9 and 2.5 kb, detected by a mouse TGF-beta 1 cDNA probe, were coordinately expressed. The concentration of these species appeared to be maximal 6-12 h after application, and returned to control levels after 48 h. A second, less intense maximum was observed 72-96 h after treatment. Similar effects were observed in CD-1 and HRS (both hr/hr and hr/+) mice, which are also sensitive to B[a[] tumorigenesis. In comparison with 32 and 64 micrograms/week a dose rate of 16 micrograms/week was essentially without activity in increasing TGF-beta 1 RNA concentration. All three dose rates induced an increase in epidermal RNA for ornithine decarboxylase, however, and with kinetics similar to those observed with the potent tumor-promoting phorbol ester 12-O-tetradecanoylphorbol-13-acetate. The results obtained support other findings made in this laboratory, that at high dose rates above 16 micrograms tumorigenesis by B[a]P involves a strong tumor-promoting component. The latter further appears to be mediated by increased TGF-beta 1 expression.

The effect of sulphur dioxide on extractable manganese in soils

Abstract The treatment of soil with SO2 caused rapid increases in concentrations of water soluble plus exchangeable (extractable) Mn. The extractable Mn increased with increasing pressure of SO2 and time of exposure, and increased with increasing water contents up to field capacity but decreased beyond this point. The addition of peat to a sandy loam increased the effect of SO2 on extractable Mn while the addition of lime decreased the effect. Reactive Mn oxides in soils may contribute significantly to SO2 sorption by soils.