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A general description of the mathematical and numerical formulations used in modern numerical reactive transport codes relevant for subsurface environmental simulations is presented. The formulations are followed by short descriptions of commonly used and available subsurface simulators that consider continuum representations of flow, transport, and reactions in porous media. These formulations are applicable to most of the subsurface environmental benchmark problems included in this special issue. The list of codes described briefly here includes PHREEQC, HPx, PHT3D, OpenGeoSys (OGS), HYTEC, ORCHESTRA, TOUGHREACT, eSTOMP, HYDROGEOCHEM, CrunchFlow, MIN3P, and PFLOTRAN. The descriptions include a high-level list of capabilities for each of the codes, along with a selective list of applications that highlight their capabilities and historical development. [ABSTRACT FROM AUTHOR]

A retrospective analysis was performed of the records of 133 patients with extrahepatic biliary atresia (EHBA) who had undergone a Kasai portoenterostomy. The patients were divided into a non-transplantation group who survived but did not receive liver transplantation after the procedure and a failure group of those who died or received liver transplantation. A score was calculated that assessed nine factors, including laboratory values and complications. The data were assessed at the time complications occurred. The scores were analysed by a trend analysis to see if serial scores predicted the evolution of liver disease. A receiver operating characteristic (ROC) curve was plotted to assess the optimal cut-point for the scoring system. There were 98 patients in the non-transplantation group and 35 in the failure group. The latter group had significantly higher post-operative bilirubin (9.3±7.2 mg/dl versus 3.5±3.1 mg/dl), ALT (136±89 U/l versus 92±88 U/l), prothrombin time, and incidence of cirrhosis, ascites, oesophageal varices, portal hypertension, cholangitis and sepsis than the non-transplantation group ( P <0.05). A score of ≥8 had a high sensitivity (96.9%) and specificity (89.5%) for predicting the need for liver transplant. Conclusion:based on easily available clinical information, our scoring system can predict which patients with biliary atresia who have already undergone a Kasai procedure should be considered for liver transplantation. [ABSTRACT FROM AUTHOR]

The fluorinated benzothiazole analogue 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203, NSC 703786) is a novel agent with potent and selective antitumour properties and, in the form of its L-lysylamide prodrug Phortress (NSC 710305), is a current candidate for early phase clinical studies. Previous findings have indicated that cytochrome P450 1A1 (CYP1A1) may play a role in the antitumour activity of molecules in the benzothiazole series including the nonfluorinated parent compound 2-(4-amino-3-methylphenyl)benzothiazole (DF 203, NSC 674495) (Kashiyama et al, 1999; Chua et al, 2000; Loaiza-Pérez et al, 2002). In this study, we assessed and verified that a fully functional aryl hydrocarbon receptor (AhR) signalling pathway is a necessary requisite for the induction of efficient cytotoxicity by 5F 203 in MCF-7 wild-type sensitive cells. Drug exposure caused MCF-7 sensitive cells to arrest in G(1) and S phase, and induced DNA adduct formation, in contrast to AhR-deficient AH(R100) variant MCF-7 cells. In sensitive MCF-7 cells, induction of CYP1A1 and CYP1B1 transcription (measured by luciferase reporter assay and real-time reverse transcriptase-polymerase chain reaction (RT-PCR)), and 7-ethoxyresorufin-O-deethylase (EROD) activity was demonstrated, following treatment with 5F 203. In contrast, in resistant AH(R100) cells, drug treatment did not affect CYP1A1 and CYP1B1 transcription and EROD activity. Furthermore, AH(R100) cells failed to produce either protein/DNA complexes on the xenobiotic responsive element (XRE) sequence of CYP1A1 promoter (measured by electrophoretic mobility shift assay) or DNA adducts. The data confirm that activation of the AhR signalling pathway is an important feature of the antitumour activity of 5F 203. [ABSTRACT FROM AUTHOR]

Summary The effect of the dietary flavonoid galangin on the metabolism of 7,12-dimethylbenz[a]anthracene (DMBA), the activity of (cytochrome P[SUB450] 1A1 (CYP1A1), and the expression of CYP1A1 in MCF-7 human breast carcinoma cells was investigated. Galangin inhibited the catabolic breakdown of DMBA, as measured by thin-layer chromatography, in a dose-dependent manner. Galangin also inhibited the formation of DMBA-DNA adducts, and prevented DMBA-induced inhibition of cell growth. Galangin caused a potent, dose-dependent inhibition of CYP1A1 activity, as measured by ethoxyresorufin-O-deethylase activity, in intact cells and in microsomes isolated from DMBA-treated cells. Analysis of the inhibition kinetics by double-reciprocal plot demonstrated that galangin inhibited CYP1A1 activity in a non-competitive manner. Galangin caused an increase in the level of CYP1A1 mRNA, indicating that it may be an agonist of the aryl hydrocarbon receptor, but it inhibited the induction of CYP1A1 mRNA by DMBA or by 2,3,5,7-tetrachlorodibenzo-p-dioxin (TCDD). Galangin also inhibited the DMBA- or TCDD-induced transcription of a reporter vector containing theCYP1A1 promoter. Thus, galangin is a potent inhibitor of DMBA metabolism and an agonist/antagonist of the AhR, and may prove to be an effective chemopreventive agent. [ABSTRACT FROM AUTHOR]

Eighteen patients with non-insulin dependent diabetes mellitus (NIDDM), hypertension and nephropathy were randomized to receive captopril or enalapril for 6 months. Two patients with serum creatinine of >400 μmol/l had to be excluded from the study because of rapidly deteriorating renal function after starting treatment. Of the remaining patients, 7 received captopril and 9 received enalapril. Blood pressure control was achieved in about 50% of patients with either drug alone. Serum creatinine and creatinine clearance were unchanged in both groups but there was a greater tendency for the former to increase in patients with higher pretreatment values. Proteinuria was reduced at 1 month only in the enalapril group which also showed a significant elevation of serum potassium after treatment. Captopril and enalapril have only a modest antihypertensive action in patients with NIDDM and nephropathy. Their use in patients with renal insufficiency must be balanced against the risk of further aggravating the deterioration of renal function. [ABSTRACT FROM AUTHOR]

Small-angle x-ray scattering (SAXS) was used to determine the structural changes in polyethylene induced by radiation. The changes in densities of the crystalline and amorphous phases, ρ and ρ, were calculated after direct determination of the mean square density fluctuation <η>. ρ increases with increasing radiation dose for both linear and branched polyethylene. This accounts for the serious discrepancy between crystallinities determined from wide-angle x-ray scattering and density measurements. This study confirms our previous proposal that crosslinks occur primarily in the noncrystalline phase, most likely at the defects in the lateral grain boundary regions. [ABSTRACT FROM AUTHOR]

Small-angle x-ray scattering (SAXS) was used to determine density fluctuation in radiation-induced crosslinked polyethylene of varying degrees of crystallinity. Density fluctuation FL decreases with increasing crystallinity, while it increases linearly with increasing radiation dose or degree of crosslinking. By means of extrapolation, density fluctuations in the crystalline and the amorphous phases FL and FL were obtained. At a given dose, FL is greater than FL. The increase in FL with radiation is found to be much greater than that of FL compared with the initial values at 0 Mrad, FL showing only a negligible increase event at 312 Mrad. The present findings suggest that crosslinks are not introduced within the crystalline phase; they take place primarily in the noncrystalline phase, in agreement with the conclusions reached previously on the basis of changes in crystalline and amorphous densities in irradiated polyethylene. [ABSTRACT FROM AUTHOR]

A theory of strain-crystallization of random networks comprised of stereoregular chains is developed. The crosslinks are assumed to be expelled from crystal cores. For this reason, the rubber is considered to be represented as a random eutectoid copolymer, the thermodynamics of strain crystallisation of which is described by the use of the van der Waals model of networks. The strain dependence of the maximum melting temperatures, the degree of crystallinity and the average thickness of the crystallites calculated are shown to be in fair accord with experimental data. [ABSTRACT FROM AUTHOR]

Branched polyethylene irradiated (0-400 Mrad) with a Co source at room temperature under vacuum was studied by density, wide- and small-angle X-ray scattering (WAXS and SAXS) measurements. The radiation effects on the structure of bulk, branched polyethylene are quite similar to those observed by others on single crystals or oriented preparations. These effects include changes in bulk density ϱ, crystallinity (w or v) and ¯d and ¯d spacings as a function of irradiation. A decrease in crystallinity is seen to begin at radiation dose ≈100 Mrad whereas lattice expansion indicating onset of an orthorhombic-hexagonal transition can begin as low as 10 Mrads. The decrease in crystallinity can be attributed to additional lattice distortions primarily introduced by the crosslinks occurring at the lateral grain boundaries, while lattice expansion can be associated with the same crosslinking mechanism which begins at the defects both within the crystals as well as those outside the crystals at the lateral grain boundaries. Strong evidence for a primary crosslinking-at-the-defects mechanism has also come from ϱ and ϱ data obtained in this study as a function of radiation dose. The same data have also led to an excellent correspondence between the measured density crystallinity v and the measured WAXS crystallinity w. Without consideration of the effects of crosslinks on ϱ and ϱ one would have obtained a divergence of the two crystallinities, especially at radiation doses greater than 100 Mrads. [ABSTRACT FROM AUTHOR]

The present-day practices of electrocardiography and vectorardiography are based upon the theory that the surface potential differences can be assumed to be due to a single dipole inside the body. It is shown in this paper that a dipole cannot account for all the surface potentials due to realistic current generators, and hence the determination of the current generator from surface potential measurements based upon such a theory will lead to inconsistent representations of the heart for one and the same subject. To demonstrate this point two eccentric dipoles of different strengths and locations representing two muscle fibers are taken to be the current generator in a homogeneous spherical conductor. The exact surface potentials are then expressed by means of the 'interior sphere theorem' of the authors. With these expressions the magnitude, direction, and location of the resultant dipole are determined by the method of D. Gabor and C. V. Nelson ( J. App. Physics, 25, 413-16, 1954). The surface potentials due to this resultant dipole are again exactly expressed by means of the 'interior sphere theorem' and compared with those due to the eccentric dipoles assumed. It can be seen that the differences can be considerable. It is suggested that the multipole model of the authors ( Bull. Math. Biophysics, 20, 203-16, 1958) be used as a more accurate and the only unique representation of the heart. [ABSTRACT FROM AUTHOR]

Recently a theorem for representing current generators in a volume conductor by the superposition of a central dipole, quadrupole, octopole, etc., has been established by G. C. K. Yeh, J. Martinek, and H. de Beaumont ( Bull. Math. Biophysics, 20, 203-16, 1958). This theorem makes possible the representation of any discrete or line, surface- or volume-distributed current source by a unique model which can be determined for each given case by surface potential measurements and closed form analysis. In this paper the multipole representations of an eccentric dipole and an eccentric double-layer are obtained in terms of the various parameters of the assumed singularities, and the contributions to surface potentials due to each of the multipoles are compared. Certain numerical results corresponding to those of E. Frank ( Amer. Heart J., 46, 364-78, 1953) are carried out and compared. Furthermore, the multipole representation of a partially damaged double-layer is also determined and compared with that of an undamaged one. It is concluded that within the range of parameters corresponding to human subjects the higher-order multipoles can contribute significantly to the surface potentials compared with the dipole. [ABSTRACT FROM AUTHOR]

As far as the potential distribution outside the current generators is concerned, any current source distribution may be replaced by a suitable collection of multipoles. If these current generators lie close to the geometrical center of the volume conductor, a central dipole is a good approximation for potentials at surface points which are at considerable distances from the center. For better accuracy and for points close to the center, additional singularities such as a central quadrupole, a central octopole, etc., should be included. Potential expressions due to such multipoles in a spherical conductor can be obtained in closed forms by means of the 'interior sphere theorem'. This paper presents a method for determining successively better multipole representations of the current generators in a homogeneous conducting sphere by measuring surface potentials at a successively increasing number of points. It is shown that Einthoven's triangle and Wilson's tetrahedron in the theory of electrocardiography are first and second approximations of this method. This concept also applies to conductors of other shapes. [ABSTRACT FROM AUTHOR]

Mindfulness-based interventions (MBIs) have demonstrated therapeutic efficacy for various psychological conditions, and smartphone apps that facilitate mindfulness practice can enhance the reach and impact of MBIs. The goal of this review was to summarize the published evidence on the impact of mindfulness apps on the psychological processes known to mediate transdiagnostic symptom reduction after mindfulness practice. A literature search from January 1, 1993, to August 7, 2023 was conducted on three databases, and 28 randomized controlled trials involving 5963 adults were included. Across these 28 studies, 67 outcome comparisons were made between a mindfulness app group and a control group. Between-group effects tended to favor the mindfulness app group over the control group in three psychological process domains: repetitive negative thinking, attention regulation, and decentering/defusion. Findings were mixed in other domains (i.e., awareness, nonreactivity, non-judgment, positive affect, and acceptance). The range of populations examined, methodological concerns across studies, and problems with sustained app engagement likely contributed to mixed findings. However, effect sizes tended to be moderate to large when effects were found, and gains tended to persist at follow-up assessments two to six months later. More research is needed to better understand the impact of these apps on psychological processes of change. Clinicians interested in integrating apps into care should consider app-related factors beyond evidence of a clinical foundation and use app databases to identify suitable apps for their patients, as highlighted at the end of this review., (© 2024. The Author(s).)