bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cost‐effectiveness of prophylactic magnesium sulphate for 9996 women with pre‐eclampsia from 33 countries: economic evaluation of the Magpie Trial
Authors: Simon Judit , Gray Alastair , Duley Lelia ,   Magpie Trial Collaborative Group
Published: December 2005

Objective To assess the cost‐effectiveness of using magnesium sulphate for pre‐eclampsia to prevent eclampsia.Design Multinational trial‐based economic evaluation.Setting Thirty‐three countries participating in the Magnesium Sulphate for Prevention of Eclampsia (Magpie) Trial.Population Women (9996) with pre‐eclampsia from the Magpie Trial.Methods Outcome and hospital resource use data were available for the trial period from the Magpie Trial. Country‐specific unit costs (U.S. dollar, year 2001) were obtained subsequently from participating hospitals by questionnaire. Cost‐effectiveness was estimated for three categories of countries grouped by gross national income (GNI) into high, middle and low GNI countries using a regression model. Uncertainty was explored in sensitivity analyses.Main outcome measures Eclampsia, hospital care costs and the incremental cost per case of eclampsia prevented.Results The number of women with pre‐eclampsia who needed to receive magnesium sulphate to prevent one case of eclampsia was 324 [95% confidence interval (CI) 122, ∞] in high, 184 (95% CI 91, 6798) in middle and 43 (95% CI 30, 68) in low GNI countries. The additional hospital care cost per woman receiving magnesium sulphate was $65, $13 and $11, respectively. The incremental cost of preventing one case of eclampsia was $21,202 in high, $2473 in middle and $456 in low GNI countries. Reserving treatment for severe pre‐eclampsia would lower these estimates to $12,942, $1179 and $263.Conclusions Magnesium sulphate for pre‐eclampsia costs less and prevents more eclampsia in low GNI than in high GNI countries. Cost‐effectiveness substantially improves if it is used only for severe pre‐eclampsia, or the purchase price is reduced in low GNI countries.
Cytokines modulate routes of collagen breakdown
Authors: van der Zee Erwin , Everts Vincent , Beertsen Wouter 
Published: December 2005

AbstractIn this paper, we review recent work on collagen degradation. 2 main routes of breakdown are described and their relevance during healthy and inflammatory conditions of the periodontium is discussed. Special attention is paid to the possible role of cytokines, in particular interleukin 1 (IL‐1) and transforming growth factor β (TGF‐β), on the modulation of collagen phagocytosis and metalloproteinase production. IL‐1 has been shown to have a dual function in collagen digestion. It inhibits the intracellular phagocytic pathway, but at the same time, it strongly promotes extracellular digestion by inducing the release of collagenolytic enzymes like collagenase. TGF‐β has an opposite effect on both pathways and antagonizes IL‐1. Collagenase is released in an inactive form, and a considerable fraction of the proenzyme may become incorporated in the extracellular matrix. This reservoir of latent enzyme can be activated (for instance by plasmin). leading to a sudden and extensive breakdown of the collagenous fibre meshwork. It is suggested that this phenomenon may also take place during progressive periodontitis and could explain an episodic nature of collagenolysis. clinically resulting in bursts of attachment loss (burst hypothesis).
Protein degradation by Prevotella intermedia and Actinomyces meyeri supports the growth of non‐protein‐cleaving oral bacteria in serum
Authors: Jansen H. J. , van der Hoeven J. S. 
Published: December 2005

AbstractThe proteolytic activities of oral bacteria are thought to play an important role in the aetiology of dental abscesses. Bacteria‐derived proteases may contribute to tissue destruction, and are likely to impair host defence by degrading immunoglobulins and complement. Degraded periodontal tissue and tissue fluid are likely to constitute essential sources of nutrients in the abscess. Tissue fluid, which is derived from serum, is rich in protein and poor in carbohydrate, suggesting that breakdown of protein and fermentation of amino acids is a crucial step to generate energy for growth of the microflora. The number of oral bacterial species that perform hydrolytic cleavage of protein into polypeptides, the first step in protein degradation, is relatively small compared to the large majority of peptidase‐producing species. In this study, we therefore investigated the growth‐promoting effect of proteinase‐producing species like Prevotella intermedia and Actinomyces meyeri on the growth of some non‐proteinase producing bacteria in mixed cultures. We used serum as a substitute for the supposed natural substrate of the abscess microflora. The breakdown of serum proteins was investigated using capillary electrophoresis. Poor growth was found in mono‐ and mixed cultures of non‐proteinase producing species Eubacterium lentum. Fusobacterium nucleatum, Peptostreptococcus micros, and Streptococcus intermedius. The presence of P. intermedia in mixed cultures strongly enhanced growth of these 4 species, according to the hypothesis that the growth of the mixed cultures was peptide‐limited. The enhanced growth of P. intermedia in pronase‐digested serum indicated peptide‐limited growth of this organism in serum, despite its production of proteinase. We found that growth of monocultures of Actinomyces meyeri was poor. In contrast, A. meyeri grew well in mixed cultures and its presence stimulated growth of F. nucleatum and P. micros, suggesting a synergistic relationship. The growth of mono‐ and mixed cultures was investigated using one representative strain of each species. Thus, there is a small risk of having selected unique strains. Proteinase inhibitors reduced the growth of Porphyromonas gingivalis, Prevotella nigrescens, and P. intermedia in trypticase peptone‐yeast extract medium with, and without, IgG. Our study indicated that proteinase‐producing organisms play a key role in mixed cultures of oral bacteria in human serum by providing polypeptides for growth. This may explain their association with dental abscesses.
Fetal ultrasonography: biometric data from four African primate species
Authors: Bourry Olivier , Ouwe‐Missi‐Oukem‐Boyer Odile , Blanchard Anne , Rouquet Pierre 
Published: December 2005

AbstractBackground  Nonhuman primates are raised in large numbers in research centers and zoos. Reproductive monitoring is required to improve breeding performances. Ultrasonography is a safe method to determine gestational age and to estimate the date of parturition. However only few data are available in nonhuman primates.Methods Fetal biometric data were obtained throughout pregnancy on four African primate species, namely chimpanzee, gorilla, mandrill and patas monkey. Measurements included biparietal diameter, transverse abdominal diameter, femur and humerus length, external interorbital diameter, and fetal heart rate. Curves established from these data were compared with previously published data in chimpanzees and gorillas and with those for humans and other closely related primate species.Results The curves for the different hominids were very similar, while those for mandrills more closely resembled baboons and data for patas monkeys were comparable to those for macaques.Conclusions These data, by providing a tool to evaluate precise gestational age, will be useful for centers raising these four primate species.
Contribution of Base Flow to Nonpoint Source Pollution Loads in an Agricultural Watershed
Authors: Schilling Keith E. , Wolter Calvin F. 
Published: December 2005

AbstractNonpoint source pollution of surface water from overland flow, drainage tiles, and ground water discharge is a major cause of water quality impairment in Iowa. Nonpoint source pollution from base flow ground water was estimated in the Walnut Creek watershed by measuirng chemical loads of atrazine, nitrate, chloride, and sulfate at 18 tributary creeks and 19 tiles. Loads were measured during a stable base flow period at creeks and tiles that discharged into Walnut Creek between two stream gauges. Chemical concentrations of atrazine (< 0.1−12 μg/L), nitrate (0.1 to 15 mg/L, and chloride (1.5 to 26 mg/L) in water were similar for creek and tile samples. Water draining predominantly agricultrural row crop areas had much higher concentrations than water draining restored prairie areas. Three methods were used to estimate base flow discharge in the watershed: (1) Darcy flux; (2) watershed discharge budget; and (3) discharge‐drainage area; each yielded similar results (31.2 L/s to 62.3 L/s). Base flow loads to the main channel were esteimated by subtracting the loads from the upstream gauge; creeks and tiles, from the total load measured at the downstream gauge station. Base flow concentration for atrazine ranged from 0.15 to 0.29 μg/L and sulfate concentration ranged from 32 to 64 mg/L, whereas concentrations for nitrate and chloride were negative (−1 to −4 mg/L). Calcultaed base flow concentrations of atrazine and sulfate appeared to be reasonable estimates, but negative concentrations of nitrate and chloride imply either loss of chemical mass in the stream from upstream to downstream sampling points or measurment error. Load data suggest little contribution from base flow pollutants to Walnut Creek water quality, with most of the pollutant load derived from major tributary creeks. Results from this study have implication for dtermining total maximum daily loads in agricultural watersheds where contributions from point sources (creeks and tiles) can be used to estimate loads from nonpoint source ground water inputs.
A Model of Cells as Practical Approach to Simulate Spring Flow in the Itxina Karstic Aquifer, Basque Country, Spain
Authors: Soliz J. Gárfias , Acebo H. Llanos 
Published: December 2005

AbstractThe aim of this study is to apply a parsimonious hydrologic model to the Itxina karstic aquifer that can predict changes in discharge resulting from variable inputs (recharge). The Itxina Aquifer was divided into four cells corresponding to different recharge areas. Each cell was treated as a tank to characterize the conditions within the cell. In the model, when the reservoir boundaries coincide with the position of the siphons, the signal simulated is sensitive to input pulses of the recharge. This supports the hypothesis that the siphons are the controlling mechanism in the flow system of the aquifer. The good agreement between predicted and measured discharges demonstrates the ability of the model to simulate the flow in the Itxina Aquifer. These results demonstrated that the hydraulic conductivity increases downstream within the aquifer. The hydraulic conductivities obtained by calibration varied between 4.2 × 10–3 m/s upstream of the aquifer, 6.0 × 10–2 m/s in the central region, and 9.5 × 10–1 m/s in the lower region of the aquifer. These values seem reasonable because the underground features in the principal caves show that the density of caves increases downstream in the Itxina Aquifer. The simple representation of the system produced results comparable to traditional ground water models with fewer data requirements and calibration parameters.
Modeling Preferential Flow in Reactive Barriers: Implications for Performance and Design
Authors: Benner S.G. , Blowes D.W. , Molson J.W.H. 
Published: December 2005

AbstractReactive barriers are passive and in situ ground water treatment systems. Heterogeneities in hydraulic conductivity (K) within the aquifer‐reactive barrier system will result in higher flux rates, and reduced residence times, through portions of the barrier. These spatial variations in residence time will affect the treatment capacity of the barrier. A numerical flow model was used to evaluate the effects of spatial variations in K on preferential flow through barriers. The simulations indicate that the impact of heterogeneities in K will be a function of their location and distribution; the more localized the high K zone, the greater the preferential flow. The geometry of the reactive barrier will also strongly influence flow distribution. Aquifer heterogeneities will produce greater preferential flow in thinner barriers compared to thicker barriers. If the barrier K is heterogeneous, greater preferential flow will occur in thicker barriers. The K of the barrier will affect the flow distribution; decreasing the K of the barrier can result in more even distribution of flow. Results indicate that less variable flow will be attained utilizing thicker, homogeneous barriers. The addition of homogeneous zones to thinner barriers will be effective at redistributing flow only if installed immediately adjacent to both the up‐ and downgradient faces of the barrier.
Modeling of a Deep‐Seated Geothermal System Near Tianjin, China
Authors: Xun Zhou , Mingyou Chen , Weiming Zhao , Minglang Li 
Published: December 2005

AbstractA geothermal field is located in deep‐seated basement aquifers in the northeastern part of the North China Plain near Tianjin, China. Carbonate rocks of Ordovician and Middle and Upper Proterozoic age on the Cangxian Uplift are capable of yielding 960 to 4200 m3/d of 57°C to 96°C water to wells from a depth of more than 1000 m. A three‐dimensional nonisothermal numerical model was used to simulate and predict the spatial and temporal evolution of pressure and temperature in the geothermal system. The density of the geothermal water, which appears in the governing equations, can be expressed as a linear function of pressure, temperature, and total dissolved solids. A term describing the exchange of heat between water and rock is incorporated in the governing heat transport equation. Conductive heat flow from surrounding formations can be considered among the boundary conditions. Recent data of geothermal water production from the system were used for a first calibration of the numerical model. The calibrated model was used to predict the future changes in pressure and temperature of the geothermal water caused by two pumping schemes. The modeling results indicate that both pressure and temperature have a tendency to decrease with time and pumping. The current withdrawal rates and a pumping period of five months followed by a shut‐off period of seven months are helpful in minimizing the degradation of the geothermal resource potential in the area.
Exercises Illustrating Flow in Porous Media
Authors: Massmann Joel , Johnson Lisa 
Published: December 2005

AbstractA set of physically based exercises is described for illustrating concepts and processes related to fluid movement in porous media. These exercises revolve around a permeameter that costs several dollars to construct and requires no external equipment and no electrical power to operate. The exercises can be used to illustrate concepts related to pressure and fluid statics, Darcy's equation for both gases and liquids, infiltration, and flow in layered media. Although the permeameter was originally developed as a teaching aid, it may also be useful in field applications as a tool to estimate air and hydraulic conductivity. Additional testing is recommended to further assess the accuracy of the results for field applications.
Fluorescence of Dissolved Organic Matter as a Natural Tracer of Ground Water
Authors: Baker Andy , Lamont‐BIack John 
Published: December 2005

AbstractThe fluorescence properties of dissolved organic matter (DOM) in ground water in the Permian limestone of northeast England is determined from six monitoring boreholes, a private water supply well and from a natural resurgence in a flooded collapse doline in the environs of Darlington, County Durham, northeast England. Measurements of both protein and “fulvic‐like” fluorescence was undertaken from January to December 1999. The wavelengths of fulvic‐like fluorescence excitation and emission and of protein fluorescence emission were all determined to be sensitive fingerprints of organic matter fluxes through the ground water, with water within the till and within both gypsum and limestone strata deep inside the Magnesian Limestone being differentiated by these parameters. Previous research has suggested that proteins in waters are “young” in age, hence our seasonal variations suggest that we are sampling recently formed DOM. The rapid response of all deep borehole samples suggests relatively rapid ground water flow, probably through karstic cave systems developed in the gypsum and solution widened features in the dolomitic limestone. Our results suggest that use of both protein and fulvic‐like fluorescence wavelength variations provides a DOM signature that can be used as a natural tracer.
Fate of the Herbicides 2,4,5‐T, Atrazine, and DNOC in a Shallow, Anaerobic Aquifer Investigated by In Situ Passive Diffusive Emitters and Laboratory Batch Experiments
Authors: Arildskov N.P. , Pedersen P.G. , Albrechtsen H.‐J. 
Published: December 2005

AbstractThe fate of the three herbicides 2,4,5‐T (2,4,5‐trichlorophenoxyacetic acid), atrazine (6‐chloro‐N‐ethyl‐N′‐[l‐methyl‐ethyl]‐l,3,5‐triazine‐2,4‐diamine), and DNOC (4,6‐dinitro‐2‐methylphenol) in an anaerobic sandy aquifer was investigated. In the field, each of the herbicides was released simultaneously with tritiated water (HTO) as tracer in the depth interval 3 to 4 mbs (meters below surface) by use of passive diffusive emitters. Atrazine and 2,4,5‐T were persistent during the approximately 18 days residence time in the aquifer. In contrast, DNOC was rapidly removed from the water phase following first‐order kinetics. The removal mechanism was likely an abiotic reduction. At day 25, the first‐order rate constant was 1.47 d−1, but it decreased with time and seemed to stabilize at 0.35 d−1 after 150 to 200 days.In the laboratory, batch experiments were conducted with sediments from 3 to 4 mbs and from 8 to 9 mbs. In these incubations, formation of Fe2+ and depletion of sulfate showed iron and sulfate reduction in sediment from 3 to 3.5 mbs and sulfate reduction in 3.5 to 4 mbs sediment. In sediment from 8 to 9 mbs, the dominant redox process was methane formation. In sediment from 3 to 3.5 mbs, only 27% to 52% of the 2,4,5‐T remained after 196 days. 2,4,5‐trichlorophenol was identified as the major metabolite. A lag period of at least 50 days was observed, and no degradation occurred in HgCl2 amended controls, verifying that the process was microbially mediated. In the other 2,4,5‐T incubations and all the atrazine incubations, concentrations decreased linearly, but less than 25 % was removed within 200 to 250 days. No degradation products could be detected, and slow sorption was the likely explanation. In all the laboratory incubations DNOC was degraded, following first‐order kinetics, and when normalized to the sediment/water‐ratio, the field and laboratory derived rate constants compared well. The DNOC degradation in the methanogenic incubations (8 to 9 mbs) was up to 50 times faster than in the sediments from 3 to 4 mbs, likely due to the low redox potential.
Estimate of Recharge of a Rising Water Table in Semiarid Niger from 3H and 14C Modeling
Authors: Favreau Guillaume , Leduc Christian , Marlin Christelle , Dray Martial , Taupin Jean‐Denis , Massault Marc , Le Gal La Salle Corinne , Babic Milanka 
Published: December 2005

AbstractA hydrodynamic survey carried out in semiarid southwest Niger revealed an increase in the unconfined ground water reserves of approximately 10% over the last 50 years due to the clearing of native vegetation. Isotopic samplings (3H, 18O,2H for water and 14C, 13C for the dissolved inorganic carbon) were performed on about 3500 km2 of this silty aquifer to characterize recharge. Stable isotope analyses confirmed the indirect recharge process that had already been shown by hydrodynamic surveys and suggested the tracers are exclusively of atmospheric origin. An analytical model that takes into account the long‐term rise in the water table was used to interpret 3H and 14C contents in ground water. The natural, preclearing median annual renewal rate (i.e., recharge as a fraction of the saturated aquifer volume) lies between 0.04% and 0.06%. For representative characteristics of the aquifer (30 m of saturated thickness, porosity between 10% and 25%), this implies a recharge of between 1 and 5 mm/year, which is much lower than the estimates of 20 to 50 mm/year for recent years, obtained using hydrological and hydrodynamic methods and the same aquifer parameters. Our study, therefore, reveals that land clearing in semiarid Niger increased ground water recharge by about one order of magnitude.
Flow Depletion in a Small Stream Caused by Ground Water Abstraction from Wells
Authors: Nyholm Thomas , Christensen Steen , Rasmussen Keld R. 
Published: December 2005

AbstractThe interaction between a gaining stream and a water‐table aquifer is studied at an outwash plain. The aquifer is hydraulically well connected to the stream. Pumping tests were carried out in 1997 and 1998 in two wells 60 m from the stream, screening different depths of the aquifer. Drawdown was measured on both sides of the stream. Hydraulic head, drawdown, and stream depletion data were analyzed using numerical flow models. Similar models were fitted to each of two different data sets: Model A was fitted to steady‐state hydraulic head and streamflow gain data not influenced by pumping; and model B was fitted to drawdown data measured during the 1998 pumping test. Each calibrated model closely fits its calibration data; however, predictions were biased if model A was used to predict the calibration data of model B, and vice versa. To further test the models, they were used to predict streamflow depletion during the two pumping tests as well as the drawdown during the 1997 test. Neither of these data were used for calibration. Model A predicted the measured depletions fairly accurately during both tests, whereas the predicted drawdowns in 1997 were significantly larger than actually measured. Contrary to this, the 1997 drawdowns predicted by model B were nearly unbiased; the predicted depletions deviate significantly from the measured depletions in 1997, but they compare well with the observations in 1998. Thus, although field work and analyses were extensive and done carefully to develop a ground water flow model that could predict both drawdown and streamflow depletion, the model predictions are biased. Analyses indicate that the deviations between model and data may be because of error in the models' representations of either the release of water from storage or of the hydrology in the riparian zone.