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Modeling water distribution and flow in partially saturated soils requires knowledge of the soil water characteristic (SWC). However, measurement of the SWC is challenging and time-consuming and, in some cases, not feasible. This study introduces two predictive models (FW-model and AW-model) for the SWC, derived from readily available soil properties such as texture and bulk density. A total of 46 undisturbed soils from different horizons at 15 locations across Denmark were used for model evaluation. The FW-model predicts the volumetric water content as a function of volumetric fines content (organic matter and clay). It performed reasonably well for the dry-end of SWC (above a pF value of 2.0; pF = log(|ψ|), where ψ is the matric potential in cm), but did not do as well closer to saturated conditions. The Aw-model predicts the volumetric water content as a function of volumetric content of different particle size fractions (organic matter, clay, silt, and fine and coarse sands). The volumetric content of a particular soil particle size fraction was considered if it contributed to the pore size fraction still occupied with water at the given pF value. Hereby, the Aw-model implicitly assumes that a given particle size fraction creates an analogue pore size fraction and further this pore size fraction filled with water is corresponding to a certain pF value according to the well-known capillary rise equation. The AW-model was found to be quite robust, and it performed exceptionally well for pF values ranging from 0.4 to 4.2 for different soil types. For prediction of the continuous SWC, it is recommended to parameterize the van Genuchten model based on the SWC data points predicted by the Aw-model. [ABSTRACT FROM AUTHOR]

Growing plants in extraterrestrial environments, for example on a space station or in a future lunar or Martian outpost, is a challenge that has attracted increasing interest over the last few decades. Most of the essential plant needs for optimal growth (air, water, and nutrient supply, and mechanical support) are closely linked with the basic physical properties of the growth media. Diffusion is the main process whereby oxygen and nutrients are supplied to plant roots, and gas and solute diffusivity are the key parameters controlling the diffusive movement of oxygen and nutrients in the root zone. As one among several essential aspects of optimal porous media design for plant growth, this study presents a diffusion-based characterization of four commercial, aggregated growth media. To account for the observed large percolation threshold for gas diffusivity in the selected media, an inactive pore and density corrected (IPDC) model was developed and excellently described measured gas diffusivity in both inter- and intraaggregate pore regions. A strong relation (r² = 0.98) between percolation threshold for gas diffusivity and mean particle (aggregate) diameter was found and suggested to be used in future design models. Also, critical windows of diffusivity (CWD) was defined identifying the air content range where gas diffusivity (hence, oxygen supply) and solute diffusivity or the analogous electrical conductivity (hence, nutrient supply) are above pre-defined, critical minimum values. Assuming different critical values for gas diffusivity under terrestrial and Martian conditions, the four growth media were compared and it was found that one medium did not fulfill the pre-set criteria. Overall, the analyses suggested that particle (aggregate) sizes below 0.25 and above 5 mm should likely be avoided when designing safe plant growth media for space. The CWD concept was also applied to a natural volcanic ash soil (Nishi-Tokyo, Japan), and the natural soil was found competitive or better than the tested commercial growth media. This could bear large perspectives for Martian outpost missions, since NASA has found that Martian dust/soil mostly resembles volcanic ash soil among terrestrial materials. [ABSTRACT FROM AUTHOR]

The gas diffusion coefficient (Ds,g) and solute diffusion coefficient (Ds,l) and their dependencies on fluid content (κ) (equal to soil-air content θ for Ds,g and soil-water content ε for Ds,l) are controlling factors for gas and solute transport in variably saturated soils. In this study, we propose unified, predictive models for Ds,g(ε) and Ds,l(θ) based on modifying and extending the classical Maxwell model at fluid saturation with a fluid-induced reduction term including a percolation threshold (εth for Ds,g and θth for Ds,l). Different percolation threshold terms adopted from recent studies for gas (Ds,g) and solute (Ds,l) diffusion were applied. For gas diffusion, εth was a function of bulk density (total porosity), while for solute diffusion θth was best described by volumetric content of finer soil particles (clay and organic matter), FINESvol. The resulting LIquid and GAs diffusivity and tortuosity (LIGA) models were tested against Ds,g and Ds,l data for differently-textured soils and performed well against the measured data across soil types. A sensitivity analysis using the new Maxwell's Law based LIGA models implied that the liquid phase but not the gaseous-phase tortuosity was controlled by soil type. The analyses also suggested very different pathways and fluid-phase connectivity for gas and solute diffusion in unsaturated soil. In conclusion, the commonly applied strategy of using the same, soil-type-independent model for gas and solute diffusivity in analytical and numerical models for chemical transport and fate in variably-saturated soils appears invalid, except for highly sandy soils. The unified LIGA model with differing percolation thresholds for diffusion in the liquid and gaseous phases solves this problem. [ABSTRACT FROM AUTHOR]

Subsurface gaseous-phase transport is governed by three gas transport parameters: the air permeability coefficient (ka), gas diffusion coefficient (DP), and gas dispersion coefficient (DH). Among these, DH is the least understood due to hitherto limited research into the relationship between gas dispersion and soil physical characteristics. In this study, a series of advection--dispersion experiments was performed on granular porous media to identify the effects of soil column dimensions (length and diameter), particle size and shape, dry bulk density, and moisture content on the magnitude of gas dispersion. Glass beads and various sands of different shapes (angular and rounded) with mean particle diameters (d50) ranging from 0.19 to 1.51 mm at both air-dry and variable moisture contents were used as granular porous media. Gas dispersion coefficients and gas dispersivities (α = DH/v, where v is the pore-gas velocity) were determined by fitting the advection--dispersion equation to the measured breakthrough curves. For all test conditions, DH increased linearly with v. The test results showed that neither soil column length nor diameter had significant effect on gas dispersivity. Under air-dry conditions, higher gas dispersivities were observed for media with wider particle size distribution and higher dry bulk density. The minor effect of particle shape on gas dispersivity was found under both air-dry and wet conditions. Under wet conditions, the variations in gas dispersivity were mainly controlled by the air-filled porosity. An empirical model was also proposed for the prediction of gas dispersivity in granular, unsaturated porous media. [ABSTRACT FROM AUTHOR]

A unified measurement system with Suction control (UMS—SC) was developed for measuring soil water characteristics curves (SWCC) and gas transport parameters under alternating drying and wetting cycles. The new system consists of a diffusion chamber, sample ring, porous plate, tensiometer, moisture sensor, oxygen electrodes, and air pressure gauges. The SWCC and gas transport parameters [gas diffusion coefficient (Dp) and air permeability (ka)] for two different porous materials, Toyoura sand and granulated slag, were simultaneously measured under drying and wetting cycles. The SWCC and gas transport parameters measured by UMSSC were consistent with recent models and independently measured data on exactly the same materials using standard experimental setups from literature. For an applied water suction head of less than 50 cm and corresponding water saturation of around 0.3-0.5, the UMS—SC data documented hysteretic (nonsingular) behavior in both measured Dp and κa under repeated drying and wetting cycles. The hysteretic behavior was insignificant for water and air contents but large for both gas transport parameters when applying suction, and hysteretic effects were larger for air permeability than for gas diffusivity. Additionally, hysteresis in the percolation threshold (soil-air content where gas transport ceases due to interconnected water-filled pores) for both gas diffusion and air permeability was insignificant for both materials. These findings should be taken into account when developing models for diffusive and convective gas transport and their parameters in variably saturated porous media. [ABSTRACT FROM AUTHOR]

A series of column experiments was conducted to investigate the transport and deposition of variably charged colloids in saturated porous media. Soil colloids with diameters <1 μm were extracted from a volcanic‐ash soil from Nishi‐Tokyo (referred to here as VAS colloids) and a red‐yellow soil from Okinawa (RYS colloids) in Japan. The VAS colloids exhibited a negative surface charge with a high pH dependency, whereas the RYS colloids exhibited a negative surface charge with less pH dependency. The soil colloids were applied as colloidal suspensions to 10‐cm‐long saturated sand columns packed with either Narita sand (mean diameter = 0.64 mm) or Toyoura sand (mean diameter = 0.21 mm) at different flow rates, suspension concentrations, and pH conditions. Both sands exhibited a negative surface charge in the measured pH range, but the pH dependency was more pronounced for the Toyoura sand. Breakthrough curves and deposition profiles for soil colloids were strong functions of the hydrodynamics, solution pH, and surface charge of the colloids and sand grains. Greater deposition was typical for lower flow rates and lower pH. The deposition of VAS colloids in both sands under low‐pH conditions exhibited depth‐dependent retention, with high colloid deposition at the column inlet. The RYS colloids were mainly deposited uniformly along columns, and depth‐dependent retention was observed only in Toyoura sand at low pH. Results suggest that decreasing solution pH enhanced surface charge neutralization of both soil colloids and sand grains, thereby increasing colloid deposition. This study emphasizes that the pH‐dependent surface charge of both mobile colloids and receiving porous media needs more consideration in models for colloid and colloid‐facilitated transport in soil. [ABSTRACT FROM AUTHOR]

Accurate predictions of the soil-gas diffusivity (Dp/Do, where Dp is the soil-gas diffusion coefficient and Do is the diffusion coefficient in free air) from easily measureable parameters like air-filled porosity (e) and soil total porosity (ε) are valuable when predicting soil aeration and the emission of greenhouse gases and gaseous-phase contaminants from soils. Soil type (texture) and soil density (compaction) are two key factors controlling gas diffusivity in soils. We extended a recently presented density-corrected Dp (ε)/Do model by letting both model parameters (α and beta;) be interdependent and also functions of φ. The extension was based on literature measurements on Dutch and Danish soils ranging from sand to peat. The parameter α showed a promising linear relation to total porosity, while β also varied with α following a weak linear relation. The thus generalized density-corrected (GDC) model gave improved predictions of diffusivity across a wide range of soil types and density levels when tested against two independent data sets (total of 280 undisturbed soils or soil layers) representing Danish soil profile data (0-8 m below the ground surface) and performed better than existing models. The GDC model was further extended to describe two-region (bimodal) soils and could describe and predict Dp/Do well for both different soil aggregate size fractions and variably compacted volcanic ash soils. A possible use of the new GDC model is engineering applications such as the design of highly compacted landfill site caps. [ABSTRACT FROM AUTHOR]

Accurate description of the soil water retention curve (SWRC) at low water contents is important for simulating water dynamics and biochemical vadose zone processes in arid environments. Soil water retention data corresponding to matric potentials of less than −10 MPa, where adsorptive forces dominate over capillary forces, have also been used to estimate soil specific surface area (SA). In the present study, the dry end of the SWRC was measured with a chilled-mirror dew point psychrometer for 41 Danish soils covering a wide range of clay (CL) and organic carbon (OC) contents. The 41 soils were classified into four groups on the basis of the Dexter number (n = CL/OC), and the Tuller-Or (TO) general scaling model describing water film thickness at a given matric potential (<−10 MPa) was evaluated. The SA estimated from the dry end of the SWRC (SA_SWRC) was in good agreement with the SA measured with ethylene glycol monoethyl ether (SA_EGME) only for organic soils with n > 10. A strong correlation between the ratio of the two surface area estimates and the Dexter number was observed and applied as an additional scaling function in the TO model to rescale the soil water retention curve at low water contents. However, the TO model still overestimated water film thickness at potentials approaching ovendry condition (about −800 MPa). The semi-log linear Campbell-Shiozawa-Rossi-Nimmo (CSRN) model showed better fits for all investigated soils from −10 to −800 MPa and yielded high correlations with CL and SA. It is therefore recommended to apply the empirical CSRN model for predicting the dry part of the water retention curve (−10 to −800 MPa) from measured soil texture or surface area. Further research should aim to modify the more physically based TO model to obtain better descriptions of the SWRC in the very dry range (−300 to −800 MPa). [ABSTRACT FROM AUTHOR]

The air permeability (ka) and soil gas diffusion coefficients (Dp) are controlling factors for gas transport and fate in variably saturated soils. We developed a unified model for ka and Dp based on the classical Archie's law, extended by: (i) allowing for two-region gas transport behavior for structured soils, with the natural field moisture condition (set at -100 cm H2O matric potential [pF 2]) as the reference (spliced) point between the large-pore (drained pore diameter ≥30 μm at pF ≤ 2) and the small-pore (subsequently drained pores <30 μm at pF > 2) regions, and (ii) including a percolation threshold, set as 10% of the total porosity for structureless porous media or 10% of the porosity in the large-pore region for structured soils. The resulting extended Archie's law with reference point (EXAR) models for ka and Dp were fitted to the measured data. For both structureless and structure porous media, Archie's saturation exponent (n) was higher for Dp than for ka, indicating higher water blockage effects on gas diffusion. For structured soils, the saturation exponent for the large-pore region (n1) was lower than for the small-pore region (n2). Generally, n1 values of ∼ 1 for ka and 2 for Dp and n2 values of 4/3 for ka and 7/3 for Dp described the data well. Two reference-point expressions for ka at pF 2 were also developed and tested together with existing models for Dp at pF 2 against independent data across soil types. The best-performing reference-point models were a ka model based on the classical Kozeny equation and the Moldrup Dp model. [ABSTRACT FROM AUTHOR]

The article discusses a research study which investigated the role of Wnt antagonist DKK1 as a tumor suppressor gene in renal cell carcinoma (RCC). The study found that the expression of DKK1 gene is genetically silenced in kidney cancer. The reexpression of DKK1 gene was found to induce apoptosis and cell cycle arrest in RCC.

Secreted frizzled-related protein-5 ( sFRP-5) has been identified as 1 of the secreted antagonists that bind Wnt protein. However, the functional significance of sFRP-5 in renal cell cancer (RCC) has not been reported. We hypothesized that sFRP-5 may be epigenetically downregulated through DNA methylation and histone modification and function as a tumor suppressor gene in RCC. Using tissue microarray and real-time RT-PCR, we found that sFRP-5 was significantly downregulated in kidney cancer tissues and cell lines, respectively. DNA bisulfite sequencing of the sFRP-5 promoter region in RCC cell lines showed it to be densely methylated, whereas there was few promoter methylation in normal kidney. The sFRP-5 expression was restored and the acetylation of H3 and H4 histones associated with the sFRP-5 promoter region were significantly increased after treatment with demethylation agent (5-Aza-dc) and histone deacetylase inhibitor (TSA). When RCC cells were transfected with the sFRP-5 gene, significant inhibition of anchorage independent colony formation and cell invasion were observed compared to controls. The sFRP-5 transfection also significantly induced apoptosis in RCC cells. In conclusion, this is the first report documenting that the sFRP-5 is downregulated by promoter methylation and histone acetylation and functions as a tumor suppressor gene by inducing apoptosis in RCC cells. [ABSTRACT FROM AUTHOR]

Describing and predicting gas and solute diffusivities and electrical and thermal conductivities under variably saturated fluid conditions are necessary for simulating gas, solute, and heat transport in soils. On the basis of comprehensive data for gas (Dp) and solute (Ds) diffusivities and electrical (EC) and thermal (TC) conductivities for differently textured and variably saturated soils, we investigated analogies and differences between the four parameters. At fluid (water or air) saturation, relative parameter values for Dp, Ds, and EC were all well described by an excluded-volume expansion of Archie's first law. The cementation exponent in Archie's first law was close to 1.5 for all parameters. At fluid-unsaturated conditions, relative values of Dp, Ds, and EC (normalized at fluid saturation) were well described by an excluded-volume expansion of Archie's second law. In the case of relative TC, the saturation exponent in Archie's second law was substituted by the inverse of it for the three other parameters since water bridge effects dramatically enhance the TC with increasing moisture contents in relatively dry porous media. If appropriate but different expressions for a percolation threshold in Archie's second law were applied for the four parameters, a saturation exponent value of around 2.0 generally gave accurate predictions of all four parameters for differently textured soils. Finally, the excluded-volume expansion of Archie's second law was modified to also represent porous media with bimodal pore size distribution and well-described data for Dp and Ds in aggregated soil. [ABSTRACT FROM AUTHOR]

The soil gas diffusion coefficient (Dp) and its dependency on soil air content, ϵ, and tortuosity-connectivity of the air-filled pore networks control the transport and fate of gaseous-phase contaminants in variably saturated soil. The bimodality pin ore size distribution of structured soil often yields a variation of Dp with ϵ in the intraagggre ate pore region that is distinctly different from that in the interaggregate region. Data imply a highly nonlinear behavior of soil gas diffusivity, Dp(ϵ)/D0 (where D0 is the gas diffusion coefficient in free air), in the interaggregate region of aggregated soils similar to that of structureless soils with a unimodal pore size distribution, probably due to diffusion-limiting effects by connected water films at low ϵ. In contrast, for the intraaggregate region, we show that the impedance factor F* (= Dp/ϵD0 ) and tortuosity factor T [= (1/F*)1/2] are approximately constant for most soil media. We suggest a typically well-defined separation between the two pore regions at the minimum for the pore connectivity factor X* [= log(Dp/D0)/log(ϵ)], at which point the interaggregate pores are devoid of water while the intraaggregate pore region is water saturated. Based on this, a hierarchical two independent region (TIR) Dp/D0 model was developed by applying a cumulative series of Buckingham-Currie power-law functions, FϵX. A nonlinear, water-content-dependent expression for F best described the measured Dp/D0 in the interaggregare region, while constant F (around 0.5) and X (around 1) generally sufficed for the intraaggregate region. The TIR model better predicted gas diffusivities for both aggregate fractions and highly structured soils across the entire range of moisture conditions with RMSE reduced by two to five times compared with traditional-predictive Dp(ϵ)/D0 models. [ABSTRACT FROM AUTHOR]

The transport of gaseous compounds in soil takes place by gas diffusion, advection, and dispersion. Gas transport processes arc influenced by the soil-gas diffusion coefficient (DH), air permeability (ka) and soil-gas dispersion coefficient (DH), respectively. Of three gas transport parameters, DH is the least understood, especially how it is correlated to soil type, moisture conditions, and other transport parameters (i.e., Dp and ka). In this study, a unified measurement system (UMS) that enables sequential measurement of Dp, ka, and DH on the same soil core was developed. The experimental sequence is based on a two-chamber measurement of DH and ka, followed by a one-chamber measurement of Dp. Gaseous oxygen concentration and air pressure sensors are located in inlet and outlet cham6ers as well as at multiple points along the soil column. Using different particle-size fractions of non-aggregated (Toyoura sand) and aggregated (Nishi-Tokyo loam) soils, the effects of soil structure, particle (aggregate) size, and column scale (5-cm i.d. and 30-cm or 60-cm length) on the three gas transport parameters were investigated. For both soils, DH linearly increased with increasing pore-air velocity. For Toyoura sand, gas dispersivity (λ = DH/u0) decreased with increasing soil-air content, while for Nishi-Tokyo loam, gas dispersiviry decreased with increasingsoil-air content to a minimum value when inter-aggregate pores were drained and increased again when the pores inside the soil aggregates started to act as tortuous air-filled pathways. In the arterial pore region (corresponding to the total pore volume for Narita sand and the inter-aggregate pore volume for Nishi-Tokyo loam), a linear relation between tortuosity of the air-filled pore network (T, calculated from Dp) and the gas dispersivity λ was observed. [ABSTRACT FROM AUTHOR]

OBJECTIVE To determine the combined effects of nerve growth factor (NGF) and vascular endothelial growth factor (VEGF) on regeneration of the bladder acellular matrix graft (BAMG) in spinal cord injury (SCI)-mediated neurogenic bladder in rats. MATERIALS AND METHODS In all, 40 female Sprague-Dawley rats were used. At 8 weeks after spinalization surgery (neurogenic bladder), they were divided into five groups consisting of untreated controls and those whose bladders were injected with either no growth factor, NGF (2 µg/rat), VEGF (2 µg/rat) or both at partial BAMG replacement surgery. After 8 weeks, bladder function was assessed by urodynamic studies and the bladders were harvested for histological examination. Smooth muscle induction, collagen and nerve fibre regeneration were assessed immunohistochemically using antibodies to smooth muscle actin (α-actin), Masson’s trichrome and protein gene product 9.5, respectively. RESULTS Bladder capacity and compliance were significantly increased in all BAMG groups 8 weeks after surgery compared with that before bladder replacement surgery. Bladder capacity and compliance were much higher in the VEGF and NGF combined group than in the control, or NGF and VEGF alone groups. There was no significant difference in the residual volume ratio among all groups. CONCLUSIONS This is the first report showing that NGF has a significant synergistic effect on the development, differentiation and functional restoration of the BAMG when administered with VEGF in neurogenic bladder. Our results indicate that NGF may be a useful cytokine for enhancing the regeneration of a functional bladder following acellular matrix grafting in a neurogenic rat model. [ABSTRACT FROM AUTHOR]

Secreted frizzled-related protein 2 ( sFRP2) is a negative modulator of the Wingless-type (Wnt) signaling pathway, and shown to be inactivated in renal cell carcinoma (RCC). However, the molecular mechanism of silencing of sFRP2 is not fully understood. Our study was designed to elucidate the silencing mechanism of sFRP2 in RCC. Expression of sFRP2 was examined in 20 pairs of primary cancers by immunohistochemistry. Kidney cell lines (HK-2, Caki-1, Caki-2, A-498 and ACHN) were analyzed for sFRP2 expression using real-time RT-PCR and Western blotting. The methylation status at 46 CpG sites of the 2 CpG islands in the sFRP2 promoter was characterized by bisulfite DNA sequencing. Histone modifications were assessed by chromatin immunoprecipitation (ChIP) assay using antibodies against AcH3, AcH4, H3K4 and H3K9. sFRP2 was frequently repressed in primary cancers and in RCC cells. The majority of sFRP2 negative cells had a methylated promoter. Meanwhile, sFRP2 expression was repressed by a hypomethylated promoter in Caki-1 cells, and these cells had a repressive histone modification at the promoter. In Caki-1 cells, sFRP2 was reactivated by trichostatin A (TSA). Repressive histone modifications were also observed in RCC cells with hypermethylated promoters, but sFRP2 was reactivated only by 5-aza-2′-deoxycytidine (DAC) and not by TSA. However, the activation of the silenced sFRP2 gene could be achieved in all cells using a combination of DAC and TSA. This is the first report indicating that aberrant DNA methylation and histone modifications work together to silence the sFRP2 gene in RCC cells. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Genistein is a phytoestrogen that has been reported to suppress the AKT signaling pathway in several malignancies. However, the molecular mechanism of genistein action is not known. We tested the hypothesis that genistein activates expression of several aberrantly silenced tumor suppressor genes (TSGs) that have unmethylated promoters such as PTEN, CYLD, p53 and FOXO3a. We report here that genistein activates TSGs through remodeling of the heterochromatic domains at promoters in prostate cancer cells by modulating histone H3-Lysine 9 (H3-K9) methylation and deacetylation. Genistein activation involved demethylation and acetylation of H3-K9 at the PTEN and the CYLD promoter, while acetylation of H3-K9 at the p53 and the FOXO3a promoter occurred through reduction of endogenous SIRT1 activity. There was a decrease of SIRT1 expression and accumulation of SIRT1 in the cytoplasm from the nucleus. Increased expression of these TSGs was also reciprocally related to attenuation of phosphorylated-AKT and NF-κB binding activity in prostate cancer cells. This is the first report describing a novel epigenetic pathway that activates TSGs by modulating either histone H3-Lysine 9 (H3-K9) methylation or deacetylation at gene promoters leading to inhibition of the AKT signaling pathway. These findings strengthen the understanding of how genistein may be chemoprotective in prostate cancer. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Background: In estrogen biosynthetic pathways, many enzymes are important for metabolism, detoxification, and bioavailability. Polymorphisms in these genes may have an effect on the enzymes' function. For example, higher expression and activation of biosynthetic enzymes and lower expression and activation of conjugation enzymes may lead to high toxicity or carcinogenesis. The authors hypothesized that single nucleotide polymorphisms (single nucleotide polymorphisms) of CYP1A1, CYP1A2, CYP1B1, CYP17, SULT1A1, SULT1E1, and SHBG genes may be risk factors for endometrial cancer.Methods: DNA samples from 150 cases of endometrial cancer and healthy controls (n = 165) were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to determine the genotypic frequency of 13 different polymorphic loci on the CYP1A1 (m1, m2, m3, m4), CYP1A2 1F, CYP1B1 codon432, COMT codon158, CYP17, SULT1A1 (Arg213His, 14A/G, 85C/T in the 3' flanking region), SULT1E1-64G/A promoter region, and SHBG genes. Genotyping was validated by direct DNA sequencing. The authors also investigated the relation between expression of CYP1A1 in endometrial cancer tissues and genotypes of CYP1A1 m1.Results: A decreased frequency of TC + CC genotype of the CYP1A1 m1 (T/C) polymorphism was observed in endometrial cancer patients compared with controls (OR = 0.42; 95% CI, 0.27-0.69). The T-A haplotype of CYP1A1 m1 and m2 was increased in endometrial cancer patients (P = .017). The frequency of CYP1A1 m1 T/C + C/C was higher in a high CYP1A1 expression group (P = .009). The authors also found that individuals carrying the variants of SULT1A1 codon213 and 2 single nucleotide polymorphisms in the 3' flanking region (14A/G and 85C/T) had an increased risk for endometrial cancer. The frequencies of G-A-C and A-G-T haplotypes of these 3 variants were higher in endometrial cancer patients (P < .0001; P = .0002). In addition, the frequency of combined genotypes (SULT1A1 213 GA + AA and CYP1A1 m1 TT) was higher in endometrial cancer patients. (OR, 4.58; 95% CI, 2.35-8.93).Conclusions: This is the first report on the combined association of CYP1A1 and SULT gene polymorphisms in endometrial cancer that suggests a decreased single nucleotide polymorphism of CYP1A1 and an increased single nucleotide polymorphism for SULT1A1 and SULT1E1 genes may be risk factors for endometrial cancer in Caucasians. [ABSTRACT FROM AUTHOR]

Water repellency (WR) of soils can induce hydrological problems such as reduced water infiltration, enhanced surface runoff and erosion, and the forming of preferential flow pat- terns in soil. Although soil organic matter (SOM) may cause both soil aggregation and a hydrophobic-material-coating of aggregates, little is known about WR in aggregated soils. We investigated the degree of WR as functions of volumetric water content (θ) and pF [= log (-Ψ; soil-water potential)] for sieved fractions of a volcanic ash soil samples from different depths with varying soil organic carbon (SOC) contents of between 1.1 and 12.3%. Water repellency was determined by the molarity of ethanol droplet (MED) test. Water repellency was observed in the samples with Soc ≥ 4.6%, and the effects of sample pretreatments (pressure chamber desorption, air-drying at 20°C, and oven-drying at 60°C) on the degree of WR were small. The degree of WR varied greatly with both SOC content, θ, and pF. Peaks of WR were observed when the water retained in intra-aggregate pores was drained to a moderate extent with the corresponding pF values located in a relatively narrow range from 3.2 to 3.6. This indicates that the hydrophobicity of high-SOC aggregate surfaces might be enhanced the most at a specific soil-water potential. Examining relations between water repellency parameters, the integrated areas below the WR-θ and WR-pF curves were useful indexes for characterizing WR, and linear relationships between the integrated areas and both SOC and water contents at maximum repellency were found. [ABSTRACT FROM AUTHOR]

Abstract Background: We determined the long-term result of our percutaneous antegrade balloon dilation technique performed for adult patients with ureterointestinal anastomotic stricture between 1992 and 1997. Methods: Balloon dilation was performed on 13 ureterointestinal anastomotic strictures in 10 patients. After a nephrostomy was performed, a guide wire was introduced into the intestinal loop through the stenotic portion under direct observation using a ureterorenoscope. Dilation was performed using the Olbert balloon dilator (30-Fr) inserted along a guide wire into the stenotic portion. A 20-Fr or 22-Fr multihole catheter was left for approximately 6 weeks. No major complications were encountered during or after these procedures. After removal of the indwelling catheters, the progress of each patient was followed for at least 14 months. Results: Additional dilation was necessary in three of 10 patients for the recurrent stricture. The balloon dilation was ineffective in two patients with a long stenosis of the ureter or a previous history of radiation therapy for uterine cancer. Eight of 10 patients showed satisfactory outcomes during the mean follow-up period of 47.1 months. Conclusions: Based on these results, we believe that the balloon dilation could be the first line of treatment for strictures of uro-digestive anastomosis, except for some patients with a long stenosis or a previous history of intrapelvic radiation. [ABSTRACT FROM AUTHOR]

The water-induced linear reduction (WLR) model for gas diffusivity in sieved, repacked soil is extended with a media complexity factor (Cm) representing local-scale soil heterogeneity. The new structure-dependent WLR (SWLR) model hereby allows for predicting gas diffusivity in both repacked soil (Cm = 1) and intact soil (Cm typically around 2). The soil-gas diffusion is a primary driver of transport, reactions, emissions, and uptake of vadose zone gases, including oxygen, greenhouse gases, fumigants, and spilled volatile organics. The soil-gas diffusion coefficient, Dp, depends not only on soil moisture content, texture, and compaction but also on the local-scale variability of these. Different predictive models have been developed to estimate Dp in intact and repacked soil, but clear guidelines for model choice at a given soil state are lacking. In this study, the water- induced linear reduction (WLR) model for repacked soil is made adaptive for different soil structure conditions (repacked, intact) by introducing a media complexity factor (Cm ) in the dry media term of the model. With Cm = 1, the new structure-dependent WLR (SWLR) model accurately predicted soil-gas diffusivity (Dp/Do, where Do is the gas diffusion coefficient in free air) in repacked soils containing between 0 and 54% clay. With Cm = 2.1, the SWLR model on average gave excellent predictions for 290 intact soils, performing well across soil depths, textures, and compactions (dry bulk densities). The SWLR model generally outperformed similar, simple Dp/Do models also depending solely on total and air-filled porosity. With Cm = 3, the SWLR performed well as a lower-limit Dp/Do model, which is useful in terms of predicting critical air-filled porosity for adequate soil aeration. Because the SWLR model distinguishes between and well represents both repacked and intact soil conditions, this model is recommended for use in simulations of gas diffusion and fate in the soil vadose zone, for example, as a key element in developing more accurate climate change models. [ABSTRACT FROM AUTHOR]

Soil-gas diffusivity (Dp/Do) and its dependency on soil matric potential (ψ) is important when taking regulative measures (based on accurate predictions) for climate gas emissions and also risk-mitigating measures (based on upper-limit predictions) of gaseous-phase contaminant emissions. Useful information on soil functional pore structure, e.g., pore network tortuosity and connectivity, can also be revealed from Dp/Do-ψ relations. Based on Dp/Do measurements in a wide range of soil types across geographically remote vadose zone profiles, this study analyzed pore connectivity for the development of a variable pore connectivity factor, X, as a function of soil matric potential, expressed as pF (=log ∣-ψ∣), for pF values ranging from 1.0 to 3.5. The new model takes the form of X = X" (F/F")A with F = 1 + pF-1, where X" is the pore network tortuosity at reference F (F") and A is a model parameter that accounts for water blockage. The X-pF relation can be linked to drained pore size to explain the lower probability of the larger but far fewer air-filled pores at lower pF effectively interconnecting and promoting gas diffusion. The model with X" = 2 and A = 0.5 proved promising for generalizing Dp/Do predictions across soils of wide geographic contrast and yielded results comparable to those from widely used predictive models. The X-pF model additionally proved valuable for differentiating between soils (providing a unique soil structural fingerprint for each soil layer) and also between the inter- and intraaggregate pore regions of aggregated soils. We further suggest that the new model with parameter values of X" = 1.7 and A = 0 may be used for upper limit Dp/Do predictions in risk assessments of, e.g., fluxes of toxic volatile organics from soil to indoor air at polluted soil sites. [ABSTRACT FROM AUTHOR]

Soil water repellency (WR) occurs worldwide and affects hydrologic processes such as infiltration, preferential flow, and surface erosion. The degree of WR varies with soil organic C (SOC) and water contents. In this study, we measured WR (by ethanol molarity) as a function of moisture conditions for two soil profiles (17 layers, of which 13 exhibited WR), representing different vegetation and SOC between 0.6 and 14%. Generally, WR was found at SOC =2%. Based on measured data, a two-region water repellency (TRWR) model was developed. The model assumes two linear regions in a WR vs. pF (=log[-ψ], where ψis the soil water matric potential in centimeters of H2O) plot, with linear increase in WR from the moisture content where WR first occurs during drying to the maximum WR at pFWR-max, and a linear decrease from pWR-max until ambient air-dried conditions. The van Genuchten soil water retention model was used to convert WR-θ (where θis the volumetric water content) to WR-pF. The TRWR model fitting parameters, slopes, and intercepts, were all highly correlated with SOC (R² > 0.8). The TRWR model was tested against an independent data set for five soils with 2 to 12% SOC and predicted well the measured WR-θ and WR-pF relations. For high-SOC surface soils, the TRWR model seems promising to predict WR from fully wettable to ambient air-dried conditions, i.e., within the interval where WR-induced fingered water flow probably occurs. Finally, our data imply that clay saturation by SOC (quantified by the so-called Dexter index) is useful for predicting if soils are likely to exhibit WR. [ABSTRACT FROM AUTHOR]

The soil gas diffusion coefficient (D p) and air permeability (κ a) and their dependency on soil air content (ε) control gas diffusion and advection in soils. This study investigated the effects of average particle size (D 50) and dry bulk density (ρb) on D p and κ a for six sandy soils under variably saturated conditions. Data showed that particle size markedly affects the effective diameter of the drained pores active in leading gas through the sample at -100 cm H2O of soil water matric potential (calculated from D p and κ a) as well as the average pore diameter at half saturation (calculated from the water retention curve), both exhibiting similar and exponential relationships with D 50 Under variably saturated conditions, higher D p and κ a in coarser sand (larger D 50) were observed due to rapid gas diffusion and advection through the less tortuous large-pore networks. In addition, soil compaction (larger ρb) simultaneously caused reduced water blockage effects and a reduction of large-pore space, resulting in higher D p(ε) but lower κ a(ε). Two recent models for D p(ε) and κ a(ε) were evaluated: the water-induced linear reduction (WLR) model for D p, and the reference-point power law (RPL) model for κ a, with reference point κ a set at -100 cm H2O. The performance of both models for the sandy soils (particle size range 0.02-0.9 mm) was improved if the pore connectivity-tortuosity factor and water blockage factors were assumed to be functions of D 50 and ρb Water blockage factors, N for the WLR D p(ε) model and M for the RPL κ a(ε) model, showed a strong nonlinear relationship (R² = 0.95) that seems promising for predicting D p(ε) from the more easily measureable κ a(ε). [ABSTRACT FROM AUTHOR]

The solute diffusion coefficient in soil (D s) and its dependency on the soil water content (θ), soil type, and compaction govern the transport and fate of dissolved chemicals in the soil vadose zone. Only a few studies have quantified solute diffusivity (D s/D 0, where D s and D 0 are the solute diffusion coefficients in soil and pure water, respectively) for variably compacted soils with different textures. We measured the D s for KCl on five different soils from Japan: two volcanic ash soils (Andisols) at different bulk densities, two sandy soils, and a loamy soil. The D s was measured across a wide range of θ using the half-cell method. The D s/D 0 values for Andisols with bimodal pore size distribution were comparatively lower than for the other soils. Opposite to the behavior for sandy soils, the D s/D 0 for Andisols at a given θ decreased markedly with increasing bulk density under wet conditions but increased with increasing bulk density under dry conditions. Data for all soil types including sandy soils with unimodal pore size distribution implied a two-region behavior when plotted as log(D s/D 0) vs. θ. We suggest that the similar behavior across soil types can be explained by regions of low and high water phase connectivity for relatively structureless soils and by high intraaggregate and low interaggregate water phase tortuosity for aggregated soils. Among a number of tested predictive models for D s/D 0, the Penman-Millington-Quirk model, which requires knowledge of only θ and total porosity, performed best across soil types. [ABSTRACT FROM AUTHOR]

The soil gas diffusion coefficient (Dp) and its variations with soil air content &varepsilon; and soil water matric potential ψ control vadose zone transport and emissions of volatile organic chemicals and greenhouse gases. This study revisits the 1904 Buckingham power-law model where Dp is proportional to &varepsilon;X, with X characterizing the tortuosity and connectivity of air-filled pore space. One hundred years later, most models linking Dp&varepsilon; to soil water retention and pore size distribution still assume that the pore connectivity factor, X, is a constant for a given soil. We show that X varies strongly with both and matric potential [given as pF = log(-ψ, cm H2O)] for individual soils ranging from undisturbed sand to aggregated volcanic ash soils (Andisols). For Andisols with bimodal pore size distribution, the X-pF function appears symmetrical. The minimum X value is typically around 2 and was observed close to ψ of -1000 cm H2O (pF 3) when interaggregate voids are drained. To link Dp with bimodal pore size distribution, we coupled a two-region van Genuchten soil water retention model with the Buckingham Dp&varepsilon; model, assuming X to vary symmetrically around a given pF. The coupled model well described Dp as a function of both and for both repacked and undisturbed Andisols and for other soil types. By merely using average values of the three constants in the proposed symmetrical X-pF expression, predictions of Dp were better than with traditional models. [ABSTRACT FROM AUTHOR]

The main soil-gas transport parameters, gas diffusivity and air permeability, and their variations with soil type and air-filled porosity play a key role in soil-gas emission problems including volatilization of toxic chemicals at polluted sites and the production and emission of greenhouse gases. Only limited information on soil-gas transport parameters across the vadose zone is available, especially for soil layers below the root zone. In a series of studies, we developed new data for the soil-gas transport parameters in different soil profiles and tested existing and new predictive models. In this first study, we measured gas diffusivity at different soil-water matric potentials on undisturbed soil samples for three lysimeter soil profiles down to 1.4-m depth and for two field soil profiles down to 5.6-m depth, representing a total of 22 different soil layers with soil texture ranging from sand to sandy clay loam. Five commonly used predictive gas diffusivity models were tested. The three-porosity model (TPM) performed best for both shallow and deep soil layers. The tortuosity-connectivity parameter X in the TPM varied with soil texture and pore size distribution, and the TPM predicted well the depth distributions of measured soil-gas diffusivities. The TPM also requires less detailed information on the soil-water characteristic curve than other well-performing predictive models, and is therefore recommended for predicting variations in soil-gas diffusivity within the vadose zone. [ABSTRACT FROM AUTHOR]