Entrapped air can greatly affect the hydraulic conductivity at or near saturation. In this study, we measured the hydraulic conductivity and volume of entrapped air in a quasi‐saturated soil. Two ...soils, a Masa sandy loam soil from weathered granite rock and a TUAT light clay andisol from volcanic ash, were used. The soils, with three different dry bulk densities, were packed into a steel cylinder. To attain complete saturation, the packed soil samples were immersed in a 0.02 mol L−1 gypsum solution under vacuum conditions. The soil samples were then left on a sintered porous plate with suction of −17.0 kPa for different periods of time to allow drainage and air intrusion. After this drainage process, the samples were again immersed in water to permit air entrapment. The hydraulic conductivity was measured using the falling head method, and the amount of entrapped air was determined gravimetrically. The quasi‐saturated hydraulic conductivity was found to decrease with increasing entrapped air content until the soil had the maximum fraction of entrapped air, approximately 10% of the bulk soil volume. A comparison of the quasi‐saturated and unsaturated hydraulic conductivities of the soil samples at or near saturation, when the suction of soil water was greater than the air‐entry value, showed that the quasi‐saturated hydraulic conductivity was smaller than the unsaturated hydraulic conductivity.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Summary
Enhanced production of macrophage migration inhibitory factor (MIF) is recognized in patients with inflammatory bowel disease (IBD) and mice with experimental colitis; however, the precise ...molecular function of MIF in colitis is not fully understood. To further investigate this matter, we examined the pathological features of MIF transgenic mice with dextran sulphate sodium (DSS)‐induced colitis. We generated transgenic mice carrying a murine MIF cDNA driven by a cytomegalovirus enhancer and a β‐actin/β‐globin promoter. Mice were orally administered 1–4% DSS in drinking water for 7 days. Clinical disease activity, survival and histological features were evaluated. The level of myeloperoxidase (MPO) activity in the colon tissue was measured to assess neutrophil infiltration. The level of corticosterone in the serum was measured by enzyme linked‐immunosorbent assay (ELISA). MIF mRNA and protein were markedly up‐regulated in the colon and serum obtained from MIF transgenic mice. The severity of the colitis induced by 1% DSS treatment was markedly higher in MIF transgenic mice than in wild‐type mice. We also found that MPO activity was significantly higher in MIF transgenic mice than wild‐type mice in response to DSS stimulation. Interestingly, the corticosterone level remained unchanged in MIF transgenic mice. MIF enhances DSS‐induced colitis, in part via neutrophil accumulation and inhibition of glucocorticoid bioactivity.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
The first comparison of spectral responsivity scales in the soft x-ray region from 360 eV to 5000 eV has been carried out between the Physikalisch-Technische Bundesanstalt (PTB) and the National ...Institute of Advanced Industrial Science and Technology (AIST). Two semiconductor photodiodes used as transfer detectors were calibrated using monochromatized synchrotron radiation and cryogenic electrical substitution radiometers as the primary detector standards at these institutes. The primary detector standard at AIST was confirmed to be in agreement with that at PTB at the level of the relative expanded uncertainty.
The involvement of nitric oxide (NO) in human GH-releasing hormone (hGHRH)-induced GH secretion was studied with freshly dissociated male rat pituitary cells. The cells were packed in a column of ...Bio-Gel-P2 and continuously perifused at 37 C. Hemoglobin (Hb; 10 microM), which is known to strongly bind NO, potentiated 0.01, 0.1, and 1 nM hGHRH-induced GH secretion by 73%, 52%, and 39%, respectively, without affecting the basal secretion of GH. As reported previously, 1-nM or higher concentrations of hGHRH elicit an increase in GH secretion during the application of hGHRH (on-response) and also a transient increase after the cessation of hGHRH application (off-response). It was found that Hb potentiated only the off-response in 1 nM hGHRH-induced GH secretion, and the same concentration of Hb had no effect on 10 nM hGHRH-induced GH secretion. N-Methyl-L-arginine (MeArg; 500 microM), a competitive inhibitor of NO synthase, also potentiated both the on- and off-responses of 1 nM hGHRH-induced GH secretion by 39% without affecting basal GH secretion. Since cAMP is thought to be an intracellular messenger of hGHRH action, the effects of Hb and MeArg on 1 mM (Bu)2AMP-induced GH secretion were examined. Their actions were found to be greater than those in hGHRH-induced GH secretion. Excess K+ (15 and 50 mM)-induced GH secretion, which does not involve cAMP, however, was not affected by either Hb or MeArg. In contrast, 3 mM sodium nitroprusside, which releases NO, suppressed the 1 nM hGHRH-induced off-response by 18%. The same concentration of sodium nitroprusside had no effect on excess K(+)-induced GH secretion. The effect of 8-bromo-cGMP on hGHRH-induced GH secretion was also examined, since NO is thought to exert its action through cGMP by activating guanylate cyclase in neural tissue. The application of 8-bromo-cGMP, however, did not affect 1 nM hGHRH-induced GH secretion. These observations suggest that hGHRH stimulates the synthesis of NO at least partly through cAMP, thereby partially inhibiting hGHRH-induced GH secretion.
Myostatin is a negative regulator of the growth and development of skeletal muscle mass. In fish, myostatin is expressed in several organs in addition to skeletal muscle. To understand the mechanisms ...regulating myostatin gene expression in the sea perch, Lateolabrax japonicus, we examined the methylation status of the myostatin gene promoter region in several tissues (liver, eye, kidney, brain, and heart) isolated from adult specimens. The frequency of methylated cytosines was very low in all tissues, regardless of the level of myostatin expression, suggesting that DNA methylation is not involved in the tissue-specific regulation of myostatin expression. Southern blot analysis of genomic DNA obtained from micrococcal nuclease-treated nuclei showed that chromatin digestion occurs in tissues where the myostatin gene is actively transcribed and that the myostatin gene is protected from micrococcal nuclease in tissues where myostatin is not expressed. The chromatin structure in the myostatin gene region appears to regulate its expression without DNA methylation.
Enrichment is an increasingly serious trend in natural ecosystems. A theoretical model of a predator-prey system with a natural assumption of satiation in predation predicts that enrichment causes ...the populations to fluctuate to stochastic extinction. However, this 'paradox of enrichment' does not always occur in experimental and natural communities. Here we present a theoretical model that describes a novel mechanism for resolving the paradox in the case of a predator with optimal selective feeding. Specifically, a less profitable but edible (thus 'unpalatable') prey species sharply reduces the amplitude of population oscillations and firmly prevents the minimum abundances of species from falling below certain values. The presence of such an unpalatable prey thus guarantees the robustness of the system against enrichment.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
The anaerobic technology application for domestic sewage treatment in Pernambuco State (Brazil) is relatively recent. Some UASB reactors of less than 250 m3 were built in the Recife Metropolitan ...Region (RMR) in the 1990s. Mangueira (18,000 inhabitants) was the first neighborhood where the municipality built a plant with a bigger UASB reactor of 810 m3. It was intended to evaluate the performance and verify if such technology would be feasible. The objective would be the possible application of UASB reactors to the RMR, according to the new sewage master-plan under elaboration that would benefit about 3 million inhabitants. The monitoring of the Mangueira UASB reactor over 30 months showed that satisfactory results were obtained. Three distinct operational phases occurred, in which efficiency varied from 60% up to 90% based on COD removal. The results were very dependent on the operation and maintenance, either in the plant or in the sewage collection. Significant amount of inert solids was measured inside the reactor. Despite the operational problems, the UASB was shown to be very robust and stable. Under high fluctuation of influent concentrations (150-750 mg COD/L) during the period, resulting in applied organic loading rate of 0.5 to 2.5 kg COD/m3.d, the average values of COD removal efficiency did not change significantly. An active biomass with specific methanogenic activity varying from 0.18 to 0.25 g COD/g VSS.d was measured at the end of the period.
Transforming growth factor-beta (TGF-beta) elicits a potent growth inhibitory effect on many normal cells by binding to specific serine/threonine kinase receptors and activating specific Smad ...proteins, which regulate the expression of cell cycle genes, including the p21 cyclin-dependent kinase (CDK) inhibitor gene. Interestingly, cancer cells are often insensitive to the anti-mitogenic effects of TGF-beta for which the molecular mechanisms are not well understood. In this study, we found that the candidate prostate cancer susceptibility gene ELAC2 potentiates TGF-beta/Smad-induced transcriptional responses. ELAC2 associates with activated Smad2; the C-terminal MH2 domain of Smad2 interacts with the N-terminal region of ELAC2. Small interfering siRNA-mediated knock-down of ELAC2 in prostate cells suppressed TGF-beta-induced growth arrest. Moreover, ELAC2 was shown to specifically associate with the nuclear Smad2 partner, FAST-1 and to potentiate the interaction of activated Smad2 with transcription factor Sp1. Furthermore, activation of the p21 CDK inhibitor promoter by TGF-beta is potentiated by ELAC2. Taken together our data indicate an important transcriptional scaffold function for ELAC2 in TGF-beta/Smad signaling mediated growth arrest.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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