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Investigating how solid matter behaves at enormous pressures, such as those found in the deep interiors of giant planets, is a great experimental challenge. Over the past decade, computational predictions have revealed that compression to terapascal pressures may bring about counter-intuitive changes in the structure and bonding of solids as quantum mechanical forces grow in influence1–6. Although this behaviour has been observed at modest pressures in the highly compressible light alkali metals7,8, it has not been established whether it is commonplace among high-pressure solids more broadly. We used shaped laser pulses at the National Ignition Facility to compress elemental Mg up to 1.3 TPa, which is approximately four times the pressure at the Earth’s core. By directly probing the crystal structure using nanosecond-duration X-ray diffraction, we found that Mg changes its crystal structure several times with non-close-packed phases emerging at the highest pressures. Our results demonstrate that phase transformations of extremely condensed matter, previously only accessible through theoretical calculations, can now be experimentally explored.

Background Both induction chemotherapy followed by irradiation and concurrent chemotherapy and radiotherapy have been reported as valuable alternatives to total laryngectomy in patients with advanced larynx or hypopharynx cancer. We report results of the randomized phase 3 trial 24954 from the European Organization for Research and Treatment of Cancer. Methods Patients with resectable advanced squamous cell carcinoma of the larynx (tumor stage T3-T4) or hypopharynx (T2-T4), with regional lymph nodes in the neck staged as N0-N2 and with no metastasis, were randomly assigned to treatment in the sequential (or control) or the alternating (or experimental) arm. In the sequential arm, patients with a 50% or more reduction in primary tumor size after two cycles of cisplatin and 5-fluorouracil received another two cycles, followed by radiotherapy (70 Gy total). In the alternating arm, a total of four cycles of cisplatin and 5-fluorouracil (in weeks 1, 4, 7, and 10) were alternated with radiotherapy with 20 Gy during the three 2-week intervals between chemotherapy cycles (60 Gy total). All nonresponders underwent salvage surgery and postoperative radiotherapy. The Kaplan-Meier method was used to obtain time-to-event data. Results The 450 patients were randomly assigned to treatment (224 to the sequential arm and 226 to the alternating arm). Median follow-up was 6.5 years. Survival with a functional larynx was similar in sequential and alternating arms (hazard ratio of death and/or event=0.85, 95% confidence interval=0.68 to 1.06), as were median overall survival (4.4 and 5.1 years, respectively) and median progression-free interval (3.0 and 3.1 years, respectively). Grade 3 or 4 mucositis occurred in 64 (32%) of the 200 patients in the sequential arm who received radiotherapy and in 47 (21%) of the 220 patients in the alternating arm. Late severe edema and/or fibrosis was observed in 32 (16%) patients in the sequential arm and in 25 (11%) in the alternating arm. Conclusions Larynx preservation, progression-free interval, and overall survival were similar in both arms, as were acute and late toxic effects.

Canadian life and health insurers feel that the 1992 legislative reform did not meet its goals of increasing competition in the industry, nor did its competitively relevant public policy provisions, including access to the payments system, the availability of liquidity support from public institutions, and the cost of capital, level the playing field between such insurers and deposit-takers. The industry recommends that the 1997 review correct banks' legislative and regulatory privileges.

Carbon is the fourth-most prevalent element in the Universe and essential for all known life. In the elemental form it is found in multiple allotropes, including graphite, diamond and fullerenes, and it has long been predicted that even more structures can exist at pressures greater than those at Earth’s core1–3. Several phases have been predicted to exist in the multi-terapascal regime, which is important for accurate modelling of the interiors of carbon-rich exoplanets4,5. By compressing solid carbon to 2 terapascals (20 million atmospheres; more than five times the pressure at Earth’s core) using ramp-shaped laser pulses and simultaneously measuring nanosecond-duration time-resolved X-ray diffraction, we found that solid carbon retains the diamond structure far beyond its regime of predicted stability. The results confirm predictions that the strength of the tetrahedral molecular orbital bonds in diamond persists under enormous pressure, resulting in large energy barriers that hinder conversion to more-stable high-pressure allotropes1,2, just as graphite formation from metastable diamond is kinetically hindered at atmospheric pressure. This work nearly doubles the highest pressure at which X-ray diffraction has been recorded on any material.

Preserving water quality along a river basin is a multi-factorial task that depends on the management of sewers, wastewater treatment plants (WWTPs), and the dynamics of the river. This paper presents a control strategy of a reduced integrated network of WWTPs that can be used as a reference point for designing, evaluating and performing more complex strategies. The reduced network considers that the outflow of the sewers is gathered in one point from which it is distributed to three WWTPs that can treat and/or by-pass the wastewater into the river. The control strategy makes use of Model Predictive Control (MPC) and global optimization tools, such as Particle Swarm Optimization (PSO). The single input is first divided into three via PSO (one inflow per treatment plant) with a further partition into six discharging parts (two per treatment plant). Two scenarios in rain period were evaluated to improve the quality of the river regarding the concentrations of ammonium and nitrites. Simulation results showed that the control strategy improved the mean and the transient conditions of both concentrations. Further studies about the stability of the interconnected system should be evaluated.

We analyze the preservation properties of a family of reversible splitting methods when they are applied to the numerical time integration of linear differential equations defined in the unitary group. The schemes involve complex coefficients and are conjugated to unitary transformations for sufficiently small values of the time step-size. New and efficient methods up to order six are constructed and tested on the linear Schrödinger equation.

Shockwave data on mineral‐forming compounds such as Mg2SiO4are essential for understanding the interiors of Earth and other planets, but correct interpretation of these data depends on knowing the phase assemblage being probed at high pressure. Hence, direct observations of the phase or phases making up the measured states along the forsterite Hugoniot are essential to assess whether kinetic factors inhibit the achievement of the expected equilibrium, phase‐separated assemblage. Previous shock recovery experiments on forsterite, which has orthorhombic space group Pbnm, show discrepant results as to whether forsterite undergoes segregation into its equilibrium phase assemblage of compositionally distinct structures upon shock compression. Here we present the results of plate impact experiments on polycrystalline forsterite conducted at the Dynamic Compression Sector of the Advanced Photon Source. In situ X‐ray diffraction measurements were used to probe the crystal structure(s) in the shock state and to investigate potential decomposition into periclase and bridgmanite. In contrast to previous interpretations of the forsterite shock Hugoniot, we find that forsterite does not decompose but instead reaches the forsterite III structure, which is a metastable structure of Mg2SiO4with orthorhombic space group Cmc21. Chemical segregation of forsterite does not occur on the microsecond timescalesKinetic effects determine the phases present on the forsterite Hugoniot up to 73 GPa

Higgs and Goldstone modes are possible collective modes of an order parameter on spontaneously breaking a continuous symmetry. Whereas the low-energy Goldstone (phase) mode is always stable, additional symmetries are required to prevent the Higgs (amplitude) mode from rapidly decaying into low-energy excitations. In high-energy physics, where the Higgs boson1has been found after a decades-long search, the stability is ensured by Lorentz invariance. In the realm of condensed-matter physics, particle–hole symmetry can play this role2and a Higgs mode has been observed in weakly interacting superconductors3–5. However, whether the Higgs mode is also stable for strongly correlated superconductors in which particle–hole symmetry is not precisely fulfilled or whether this mode becomes overdamped has been the subject of numerous discussions6–11. Experimental evidence is still lacking, in particular owing to the difficulty of exciting the Higgs mode directly. Here, we observe the Higgs mode in a strongly interacting superfluid Fermi gas. By inducing a periodic modulation of the amplitude of the superconducting order parameter Δ, we observe an excitation resonance at the frequency 2Δ/h. For strong coupling, the peak width broadens and eventually the mode disappears when the Cooper pairs turn into tightly bound dimers signalling the eventual instability of the Higgs mode. An off-resonant radiofrequency modulation scheme applied to a strongly interacting superfluid Fermi gas reveals the presence of a Higgs mode — an oscillation of the amplitude of the superconducting order parameter.

In Canada, the insurance business faces a constant flow of changes requiring insurers, producers and regulators as well as new participants to adapt. Every means of adaptation becomes a factor [...]

Le Syndicat interdépartemental pour l’assainissement de l’agglomération parisienne (Siaap) évalue l’impact du système d’assainissement francilien sur la qualité du milieu récepteur : la Seine et la Marne. Cette évaluation passe par le déploiement de réseaux de mesures opérationnels, ainsi que par la mise en place d’outils de modélisation de la qualité des eaux. Le logiciel de modélisation ProSe (Programme Seine) a été développé par l’École des mines de Paris dans le cadre du programme de recherche Piren-Seine (programme interdisciplinaire de recherche sur l’environnement de la Seine). ProSe permet de simuler l’impact des apports de pollutions anthropiques (rejets transitoires de station d’épuration, rejets urbains de temps de pluie, rejets permanents) sur la qualité de la Seine et de la Marne lors de leur traversée de l’agglomération parisienne. Le Siaap utilise ce modèle à des fins opérationnelles pour orienter les choix d’exploitation, notamment pour la programmation des chômages d’ouvrage. Les simulations faites avec le modèle ProSe servent également à orienter les programmes d’investissement. En constante évolution, le logiciel s’est doté d’une nouvelle version dans le cadre du 6e programme de recherche du Piren-Seine (2011–2014). À la suite de ces évolutions, le groupe de travail ProSe, composé des ingénieurs et experts du Siaap et des scientifiques du Piren-Seine, a souhaité rédiger un document de synthèse décrivant les ajustements et améliorations apportés au modèle et présentant les principaux tests de validation de cette nouvelle version du logiciel. Ce travail a permis de mettre en avant l’amélioration des prédictions de plusieurs variables essentielles dans l’évaluation de la qualité des eaux : l’O2, le NH4+, le NO2−, les PO43−et la chlorophylle a.

The effect of Lys restriction followed by a repletion period on the performance of growing pigs was studied during 3 feeding phases, each lasting 28 d. A total of 47 castrated male pigs (G Performer 8.0 × Fertilis 25 pigs; Genetiporc Inc., Saint-Bernard, QC, Canada; initial BW of 26.7 ± 2.7 kg) were given each d 70% or 100% of their Lys requirements according to 1 of the following 5 sequences: 70–70–70, 70–70–100, 70–100–70, 70–100–100, or 100–100–100 (for each sequence, numbers indicate the Lys supply percentage in phase 1, 2, and 3, respectively). Individual Lys requirements were estimated daily on the basis of each pig's actual BW and feed intake and BW gain patterns obtained by regression using each pig's historical data. At the end of phase 1, the pigs given 100% of their Lys requirements had higher ADFI (P= 0.01), ADG (P< 0.01), and average daily protein deposition (P< 0.01) than did the pigs given 70% of their requirements. Similar results were observed during phases 2 and 3. At the end of phase 2, the pigs in the 70–100 sequence did not display any compensatory response, given that their ADFI, ADG, and average daily protein deposition did not differ from those of the pigs in the 100–100 sequence. Similar results were observed during phase 3. Although no compensatory growth was observed during the growing phases, the fact that the pigs in the 70–100–100 treatment were able to catch up in terms of BW and body protein mass to the pigs in the 100–100–100 sequence could indicate that a small degree of compensation did occur; these research results cannot ascertain that any compensatory growth occurred.

L'évolution des fonctions essentielles des circuits d'interconnexion, l'alimentation, la conduction, le refroidissement, l'encapsulation sont passées en revue en termes de performances demandées aux matériaux. Les possibilités apportées dans les nouveaux matériaux et les problèmes physicochimiques rencontrés, notamment dans le cas des couples vitro-céramiques/cuivre sont étudiés.

Après avoir présenté les différents concepts selon lesquels on peut envisager la protection des centrales nucléaires contre le risque d'inondation naturelle, l'auteur décrit les méthodes utilisées en France pour déterminer les crues de référence à prendre en compte dans le domaine du calage des plates- formes des centrales.

Ce projet collaboratif, mené entre le Syndicat interdépartemental pour l’assainissement de l’agglomération parisienne (Siaap) et l’université Laval à Québec dans le cadre du programme de recherche Mocopée (pour : modélisation, contrôle et optimisation des procédés d’épuration des eaux) vise à développer des modèles mathématiques capables de prédire le fonctionnement des unités de biofiltration des eaux résiduaires urbaines. L’objectif est :de simuler les performances vis-à-vis de l’enlèvement des nutriments et des particules;et de prédire l’évolution des pertes de charge dans le cas de biofiltres dédiés au traitement du carbone, à la nitrification et à la dénitrification.Cet article est consacré à l’étape de nitrification tertiaire sur Biostyr et se focalise sur la prédiction de l’abattement des nutriments et des particules. La méthode de calibration a consisté à utiliser les résultats des 15 profils de concentrations intramassifs puis les suivis des performances des biofiltres sur le long terme. Le modèle ainsi calibré prédit correctement l’évolution des concentrations résiduelles en NH4+, NO3−, NO2−, PO43−, demande chimique en oxygène (DCO) et matières en suspension (MES). Dans les cas des NO2 – et des MES, le modèle suit l’évolution globale des observations mais a tendance à lisser les concentrations résiduelles et décroche lorsque des pics ou des creux de concentrations sont observés. Pour obtenir des résultats satisfaisants, le jeu de calibration de référence issu de la littérature a dû être modifié. Ces modifications ont essentiellement concerné les paramètres de filtration et d’enlèvement des particules, les paramètres de transfert des nutriments solubles vers le biofilm et les paramètres d’aération.

Environmental effects of excess P from manure and the soaring price of phosphates are major issues in pig production. To optimize P utilization, it is crucial to improve our capacity to predict the amount of P absorbed, while taking into account the main factors of variation. Mathematical modeling can represent the complexity of the processes and interactions in determining the digestive utilization of P in growing pigs. This paper describes and evaluates a model developed to simulate the fate of the dietary forms of P in the digestive tract of growing pigs, with particular emphasis on the effect of dietary Ca and exogenous phytase on P digestive utilization. The model consists of 3 compartments associated with specific anatomical sections: stomach, proximal small intestine, and distal small intestine. The main metabolic processes occurring in these sections are, respectively, P solubilization/insolubilization and phytate P hydrolysis, and P absorption and P insolubilization. Model parameters governing these flows were derived from in vitro and in vivo literature data. The sensitivity analysis revealed that the model was stable within a large range of model parameter values (±1.5 SD). The model was able to predict the efficacy of Aspergillus nigermicrobial phytase in accordance with literature values, as well as the decreased efficacy of plant phytase compared with microbial phytase. The prediction capabilities of the model were assessed by comparing actual and simulated P and Ca apparent total-tract digestibility (ATTD) based on published pig data not used for model development. Prediction of P digestibility across 66 experiments and 281 observations was adequate [P ATTD observed = 0.24 (SE, 0.943) + 0.98 (SE, 0.0196) × P ATTD predicted; R2, 0.90; disturbance error (ED), 96.5%], whereas prediction of Ca digestibility across 47 experiments and 193 observations was less accurate (Ca ATTD observed = 11.1 + 0.75 × Ca ATTD predicted; R2, 0.78; ED, 20.4%). A lack of agreement between experimental and simulated Ca digestibility was found. This model is, therefore, useful in evaluating P digestibility for different feedstuffs and feeding strategies. It can also be used to provide insight for improving dietary P utilization, especially from plant sources, by quantifying the effect of the mean sources of variation affecting P utilization.

The far-field high-energy diffraction microscopy technique is presented in the context of high-energy synchrotron x-ray diffraction. For each grain in an illuminated polycrystalline volume, the volume-averaged lattice orientations, lattice strain tensors, and centre-of-mass (COM) coordinates may be determined to a high degree of precision: better than 0.05°, 1 × 10−4, and 0.1 pixel, respectively. Because the full lattice strain tensors are available, corresponding mean stress tensors may be calculated unambiguously using single-crystal elastic moduli. A novel formulation for orientation indexing and cell refinement is introduced and demonstrated using two examples: first, sequential indexing and lattice refinement of a single-crystal ruby standard with known COM coordinates; and second, indexing and refinement of simulated diffraction data from an aggregate of 819 individual grains using several sample rotation ranges and including the influence of experimental uncertainties. The speed of acquisition and penetration depth achievable with high-energy (that is, >50 keV) x-rays make this technique ideal for studies of strain/stress evolution in situ, as well as for residual stress analysis.

The present study was conducted to assess the effect of 2 dietary Ca concentrations on P and Ca digestive and metabolic utilization in weanling pigs fed diets providing practical concentrations of P, with or without phytase. The responses of pigs fed diets adequate or moderately deficient in Ca and P postweaning were compared. A total of 60 pigs weaned at 28 d of age were used. Two groups of 30 pigs with differing mineral status resulted from a 10-d depletion period, during which the animals received depletion diets (DD) that consisted of corn-soybean meal with either 1.42% Ca and 0.80% P (DD+) or 0.67% Ca and 0.43% P (DD−), designed to achieve the same Ca:digestible P ratio. At the end of the depletion period, a plasma sample was taken from each pig and 12 pigs (6 from each group) were slaughtered for bone assessment to establish the baseline mineral status. The animals fed the DD− diet had signs of P deficiency with reduced plasma P (13%; P< 0.01) and femur ash concentration (8%; P< 0.05), and increased plasma Ca (9%; P< 0.05) and alkaline phosphatase activity (31%; P< 0.01). For the subsequent 25-d period, the remaining 24 pigs from each group were fed 1 of 4 repletion diets: 1) 0.56% P, 1.06% Ca; 2) 0.56% P, 0.67% Ca; 3) diet 1 + 1,000 phytase units (FTU) of Natuphos phytase/kg; and 4) diet 2 + 1,000 FTU of Natuphos phytase/kg. Total feces and urine were collected from d 5 to 11, and a blood sample was taken from each pig at d 11 and 25. The initial moderate P deficiency (DD−) stimulated Ca absorption (5%; P< 0.01), irrespective of the repletion diet, and stimulated P absorption (5%; DD × phytase, P< 0.05), only when the diets contained phytase. At the end of the repletion period, because of these compensatory phenomena, the depleted pigs achieved full recovery of femur DM and ash weight when they received phytase, whereas ash concentration tended to remain reduced by 3% (P= 0.08). Phosphorus digestibility was improved in the diets supplemented with phytase (73.0 vs. 56.0%; P< 0.001), whereas an increase in dietary Ca decreased P digestibility (65.6 vs. 63.4%; P< 0.05). Those 2 effects were independent, indicating that dietary Ca reduced equally P digestibility with and without phytase and did not influence the efficiency of phytase in releasing P in the digestive tract. In pigs fed diets with phytase, however, the reduction of Ca (Ca:P from 1.9 to 1.3) increased urinary P losses 5-fold. Those extra losses were due to a lack of Ca for skeleton ash deposition, resulting in a 4% reduction in femur ash concentration. In the end, reducing the dietary Ca:P from 1.9 to 1.3 in a practical diet containing 0.56% P did not improve the efficiency of phytase in releasing P. Moreover, the reduction in dietary Ca (Ca:P) caused an imbalance between Ca and P that impaired bone mineralization.

SUMMARY: Infection of the snail, Biomphalaria glabrata , by the free-swimming miracidial stage of the human blood fluke, Schistosoma mansoni , and its subsequent development to the parasitic sporocyst stage is critical to establishment of viable infections and continued human transmission. We performed a genome-wide expression analysis of the S. mansoni miracidia and developing sporocyst using Long Serial Analysis of Gene Expression (LongSAGE). Five cDNA libraries were constructed from miracidia and in vitro cultured 6- and 20-day-old sporocysts maintained in sporocyst medium (SM) or in SM conditioned by previous cultivation with cells of the B. glabrata embryonic (Bge) cell line. We generated 21 440 SAGE tags and mapped 13 381 to the S. mansoni gene predictions (v4.0e) either by estimating theoretical 3′ UTR lengths or using existing 3′ EST sequence data. Overall, 432 transcripts were found to be differentially expressed amongst all 5 libraries. In total, 172 tags were differentially expressed between miracidia and 6-day conditioned sporocysts and 152 were differentially expressed between miracidia and 6-day unconditioned sporocysts. In addition, 53 and 45 tags, respectively, were differentially expressed in 6-day and 20-day cultured sporocysts, due to the effects of exposure to Bge cell-conditioned medium. [ABSTRACT FROM AUTHOR]

In previous work we have derived a magnitude termed the 'Mean Squared Sensitivity' (MSS) to predict the performance degradation of a MLP affected by perturbations in different parameters. The present Letter continues the same line of researching, applying a similar methodology to deal with RBF networks and to study the implications when they are affected by input noise. We obtain the corresponding analytical expression for MSS in RBF networks and validate it experimentally, using two different models for perturbations: an additive and a multiplicative model. We discuss the relationship between MSS and the generalization ability. MSS is proposed as a quantitative measurement to evaluate the noise immunity and generalization ability of a RBFN configuration, giving even more generalization to our approach.

Le risque hydrologique est analyse en insistant sur la dualite des aspects de probabilite et de consequences dommageables. L'etude d'exemples simplifies montre l'importance prise par l'attitude du gestionnaire devant le risque. Cette attitude retentit notamment sur son comportement vis a vis des incertitudes. Il faut insister sur la necessaire prise en compte par l'hydrologue d'une expression, meme simplifiee, des consequences dommageables reelles fournies par le gestionnaire ou par les membres de la cible du risque et sur l'interaction entre la valeur de l'information et “l'aversion au risque” du decideur. L'analyse est conduite selon les principes des methodes bayesiennes qui permettent une evaluation rationnelle quantifiee et complete de tous les aspects du dialogue hydrologue—decideur.

Plasma concentrations of hormones and metabolites were measured in growing steers to establish their relation with degree of feed restriction. Sixty medium frame beef steers (259 ± 29 kg) were divided in groups of five and fed during 3 mo either timothy (T) or bromegrass (B) harvested at stem elongation of the first cut or at boot stage of the aftermath. Forages were fed at one of three levels of intake: ad libitum (FF), 80% of FF, or 65% of FF. Plasma concentrations of growth hormone (GH), insulin, glucagon, insulin-like growth factor-1 (IGF-1), glucose and nonesterfied fatty acids (NEFA) were measured on day 1 and day 78 before the morning meal. The effect of a meal on GH, insulin, glucagon, IGF-1, glucose and NEFA concentrations was also determined in 24 steers sampled from 3 h before to 3 h after a meal. Severity of feed restriction resulted in a linear decrease (P < 0.05) of plasma glucagon (0.139, 0.130, 0.121 ± 0.005 ng mL–1) and IGF-1 (109, 98, 84 ± 7 ng mL–1). Insulin concentration tended to be affected quadratically (0.37, 0.35, 0.27 ± 0.04ng mL–1for FF, 80% of FF and 65% of FF, respectively, P < 0.10). Ingestion of a meal resulted in a decrease (P< 0.05) of GH, NEFA and glucose, and an increase of insulin concentrations (P< 0.05). There was a positive correlation (r= 0.53, P < 0.05) between IGF-1 and average daily gain, and lipid percentage of carcasses suggesting that IGF-1 is related to growth rate and fat accumulation in growing steers. Key words:Feed restriction, growth hormone, insulin, IGF-I, metabolites, grass silage

DNA non-homologous end joining, the major mechanism for the repair of DNA double-strands breaks (DSB) in mammalian cells requires the DNA-dependent protein kinase (DNA-PK), a complex composed of a large catalytic subunit of 460 kDa (DNA-PKcs) and the heterodimer Ku70-Ku80 that binds to double-stranded DNA ends. Mutations in any of the three subunits of DNA-PK lead to extreme radiosensitivity and DSB repair deficiency. Here we show that the 283 C-terminal amino acids of Ku80 introduced into the Chinese hamster ovary cell line CHO-K1 have a dominant negative effect. Expression of Ku(449-732) in CHO cells was verified by northern blot analysis and resulted in decreased Ku-dependent DNA end-binding activity, a diminished capacity to repair DSBs as determined by pulsed field gel electrophoresis and decreased radioresistance determined by clonogenic survival. The stable modifications observed at the molecular and cellular level suggest that this fragment of Ku80 confers a dominant negative effect providing an important mechanism to sensitise radioresistant cells.

The main architectures, learning abilities and applications of radial basis function (RBF) neural networks are well documented. However, to the best of our knowledge, no in-depth analyses have been carried out into the influence on the behaviour of the neural network arising from the use of different alternatives for the design of an RBF (different non-linear functions, distances, number of neurons, structures, etc.). Thus, as a complement to the existing intuitive knowledge, it is necessary to have a more precise understanding of the significance of the different alternatives. In the present contribution, the relevance and relative importance of the parameters involved in such a design are investigated by using a statistical tool, the ANalysis Of the VAriance (ANOVA). In order to obtain results that are widely applicable, various problems of classification, functional approximation and time series estimation are analyzed. Conclusions are drawn regarding the whole set.

The effect of feed intake level (.6, 1.0, and 1.6 × maintenance energy and protein requirements, M) on splanchnic (portal-drained viscera [PDV] plus liver) metabolism was evaluated in six multicatheterized beef steers (398 ± 27 kg), using a double 3 × 3 Latin square design. On the last day of each 21-d experimental period, six hourly blood samples were collected from arterial, portal, and hepatic vessels. Due to catheter patency, PDV fluxes were measured on five steers, and liver and splanchnic fluxes on four steers. Increasing intake elevated (P< .01) splanchnic release of total (T) amino acids (AA), through increases (P< .01) in PDV release of both essential (E) and nonessential (NE) AA, in spite of a tendency (P< .20) for increased liver removal of NEAA. The PDV release of AA N represented 27 and 51% of digested N for 1.0 and 1.6 × M, respectively. At 1.0 and 1.6 × M, the liver removed 34% of total AA released by the PDV. For individual AA, portal flux of most EAA increased (P< .05) with feed intake, and the increase (P< .10) in splanchnic flux was accompanied by increased arterial concentration for all EAA except histidine, lysine, and methionine. This suggests that these might be limiting AA for this diet. On a net basis, most individual NEAA were released by the PDV except glutamate and glutamine, which were removed by the digestive tract. There was a net removal of NEAA by the liver, except for aspartate and especially glutamate, which were released. Ammonia release by the PDV tended (P< .20) to increase with intake and represented 69, 53, and 45% of digested N at .6, 1.0, and 1.6 × M, respectively. Urea removed by the PDV, unaffected by intake, represented 32, 33, and 21% of the digested N. Arterial glucose concentration increased linearly (P< .01) with greater intake, whereas net liver and splanchnic glucose release increased in a quadratic (P< .05) manner. Net PDV glucose release represented 26% of net glucose hepatic release at 1.6 × M. Intake elevated (P< .10) both insulin and glucagon arterial concentrations, resulting from a larger increment of portal release (P< .01) than hepatic removal (P< .05). Intake-based variations in IGF-I and NEFA arterial concentrations (P< .05) were not related to changes in splanchnic metabolism. These results clearly show the crucial role of the splanchnic tissues in regulating the profile and quantity of AA and concentrations of glucose and pancreatic hormones reaching peripheral tissues.

Severe burns induce a state of immunosuppression, and the inflammatory response after burn injury may play a role in this phenomenon. This study examined the effect of the inflammatory response to endotoxin on burn-induced immunosuppression and oxidative stress. An endotoxin-resistant mouse strain (C3H/HeJ) and a normally responding mouse strain (C3H/HeN) were compared. The mice were separated into three groups of five animals for each experimental day: (1) saline, (2) buprenorphine, and (3) buprenorphine and 20% total body surface area burn. All animals were fed ad libitum. The inflammatory response was studied at 1, 4, 7, 10, and 14 days postburn. Proliferation of activated splenocytes in burn mice was significantly lower on days 7, 10, and 14 for the C3H/HeJ strain and on days 4 and 10 for the C3H/HeN strain. Globally, C3H/HeJ presented stronger immune suppression than C3H/HeN. Oxidative stress parameters (liver malonaldehyde, spleen metabolic activity, and thiol concentrations) were higher in endotoxin-resistant mice than in the control strain. Impairment of the inflammatory response was more pronounced and oxidative stress was greater in endotoxin-resistant burn mice than in normal burn controls. Buprenorphine administration was not related to depression of these immune parameters. The inflammatory response following burn injury may be beneficial to the immune system.

A dynamic mathematical model of the digestion of proteins in the small intestine of pigs was developed. The model integrates current knowledge on the transit of digesta along the small intestine, endogenous secretions, digestion of proteins, and absorption of amino acids into a mechanistic representation of digestion. The main characteristics of the model are the following: the small intestine is divided into several segments of variable length but with equal digesta retention time; the rate of transfer of digesta between segments is based on the progression of myoelectric migration complexes; pancreatic and biliary secretions are poured into the first segment, whereas intestinal secretions enter all intestinal segments; protein hydrolysis is described by first-order equations; and an intestinal absorption capacity is used to estimate absorption of hydrolyzed protein. Simulation results are consistent with observed data, although more information is needed to represent reality more closely. The sensitivity analysis shows that parameters for protein hydrolysis largely determine protein digestibility. The absorption capacity of the small intestine limits the absorption of amino acids at the beginning of a meal and modulates the appearance of amino nitrogen in the portal vein. It also shows that amino acid absorption can be limiting to protein digestibility when large amounts of protein are eaten in a single daily meal. The model is useful in evaluating the dynamics of protein digestion and absorption of feedstuffs. The model can be used in evaluating protein digestion of different feedstuffs and feeding strategies.

L'Operation Sources du WWF (Worldwide Fund for Wildlife) est une action educative de sensibilisation a la qualite des eaux souterraines. Elle implique principalement les eleves de cinquieme et sixieme primaires de Belgique. Depuis 1994, des centaines de dosages des ions nitrates ont ete effectues dans un grand nombre de sources et de puits a l'aide de bandelettes colorimetriques. A l'issue de chaque campagne, les points d'eau surveilles ont ete reportes sur une carte de Belgique ou leur couleur indique leur qualite eu egard a la concentration en nitrates. L'objectif pedagogique etant atteint, la validation de ces cartes en tant qu'image de la realite pose le probleme de la verification du lien entre la concentration reelle (mg 1-1) du point d'eau visite et sa couleur sur la carte. A cette fin, des verifications ont ete realisees sur 308 points d'eau choisis au hasard dans l'ensemble des sources et puits visites. L'analyse statistique revele que la relation entre le test colorimetrique et le controle realise en laboratoire est hautement significative. Ce resultat justifie des investigations ulterieures, notamment la mobilisation de l'information regionale pour la qualification d'un point d'eau peu surveille et la comparaison des cartes dans le temps.

Bis(hydroxy)salen.Fe complexes were designed as self-activated chemical nucleases. The presence of a hy-droxyl group on the two salicylidene moieties serve to form a hydroquinone system cooperating with the iron redox system to facilitate spontaneous formation of free radicals. We compared the DNA binding and cleaving properties of the ortho -, meta- and para -(bishydroxy) salen.Fe complexes with that of the corresponding chelate lacking the hydroxyl groups. DNA melting temperature studies indicated that the para complex exhibits the highest affinity for DNA. In addition, this para compound was considerably more potent at cleaving supercoiled plasmid DNA than the regio-isomeric ortho - and meta -hydroxy-salen.Fe complexes, even in the absence of a reducing agent, such as dithiothreitol used to activate the metal complex. The DNA cleaving activity of the para isomer is both time and concentration dependent and the complexed iron atom is absolutely essential for the sequence uniform cleavage of DNA. From a mechanistic point of view, electron spin resonance measurements suggest that DNA contributes positively to the activation of the semi-quinone system and the production of ligand radical species responsible for subsequent strand scission in the absence of a reducing agent. The para -hydroxy-salen.Fe complex has been used for detecting sequence-specific drug-DNA interactions. Specific binding of Hoechst 33258 to AT sequences and chromomycin to GC sequences were shown. The para -bis(hydroxy)salen.Fe derivative complements the tool box of footprinting reagents which can be utilised to produce efficient cleavage of DNA.

The clinical hematological toxicity of cytotoxic drugs can be acute, with a nadir of neutrophil count after 2 weeks and recovery the following week, or subacute, with a nadir of neutrophil count after 3 weeks and recovery in the following 2–3 weeks. The explanation usually given for this difference is that drugs in the first group are more toxic to mature hemopoietic precursors, while drugs of the second type are more toxic to undifferentiated cells. In an attempt to verify this hypothesis, we compared in vitrothe effect of toxic doses of etoposide and tallimustine as representatives of drugs with acute toxicity, and of BCNU, melphalan, and carzelesin as representatives of drugs with subacute toxicity. Their effects were studied separately on more differentiated and earlier progenitors represented by granulocyte–macrophage colony-forming cells (GM-CFC) and long-term culture-initiating cells (LTC-IC), respectively. Etoposide, melphalan, BCNU, and carzelesin showed higher toxicity in differentiated than in early precursors: the concentration of drug inhibiting 70% (ID70) of GM-CFC inhibited only by 10–40% the growth of LTC-IC. Tallimustine, in contrast, inhibited both GM-CFC and LTC-IC at comparable levels. These results do not correspond to the clinical pattern of myelotoxicity observed for those drugs. We conclude that the differential effects of antitumor drugs on later (GM-CFC) or earlier (LTC-IC) hemopoietic precursors may not represent a valid model for the pattern of myelotoxicity observed in humans.

Explores the presence of heavy metals like mercury, lead and cadmium in the Great Lakes ecosystem. Human exposure through ingestion of contaminated food; Effect of mercury on the brain, kidneys and developing fetus; Effects of mercury on cellular components of immune system; Results of experimental and epidemiologic studies.

We describe a simple new technique based on the affinity of imidazole and osmium tetroxide for unsaturated lipids. Organs (e.g., kidney, liver, intestine) were perfused in vivo with a glutaraldehyde solution. Tissue fragments were then immersed in a solution containing imidazole and OsO4 and are further stained with a double lead and copper citrate solution. Ultra-thin (0.06 microns) or thick (0.1-0.3 microns) sections were observed with transmission electron microscopy (80-100 kV). The method presented permits excellent visualization of cell membranes (e.g., endoplasmic reticulum, endocytotic apparatus) because it favors good resin penetration and the alkaline pH preserves cell volume. A better stereomicroscopic analysis of the relationship between cell organelles can be carried out with thick sections. The imidazole/osmium can be used routinely because the technical steps are easy and simple to follow. Furthermore, it can complement other cytochemical methods.

An homogeneous BaO ·Fe2O3 ·B2O3 glass containing 30% Fe2O3 is prepared by a splat-cooling technique. X-ray and electron diffraction reveal the product to be amorphous at room temperature. The crystallization, as shown by DTA studies, begins at 750 K, and up to 950 K, a temperature at which BaFe12O19 is shown to be present, the crystallizing products are mainly evolutive.