pinecone/core-2020-05-10-deduplication huggingface dataset:
Clock and induction model for somitogenesis

After many years of research, somitogenesis is still one of the major unresolved problems in developmental biology. Recent experimental findings show a novel type of pattern formation in which a signal sweeps along the presomitic mesoderm and narrows simultaneously as a new somite is formed. The signal then residues in the posterior half of the new somite, and another wave begins to sweep up from the caudal end. This behaviour is not easily explained by the existing theoretical models. We present a new model for somitogenesis that can account for this behaviour and is consistent with previous experimental observations. Dev Den;217:415-420. © 2000 Wiley-Liss, Inc
On large deformations of thin elasto-plastic shells: Implementation of a finite rotation model for quadrilateral shell element

A large-deformation model for thin shells composed of elasto-plastic material is presented in this work, Formulation of the shell model, equivalent to the two-dimensional Cosserat continuum, is developed from the three-dimensional continuum by employing standard assumptions on the distribution of the displacement held in the shell body, A model for thin shells is obtained by an approximation of terms describing the shell geometry. Finite rotations of the director field are described by a rotation vector formulation. An elasto-plastic constitutive model is developed based on the von Mises yield criterion and isotropic hardening. In this work, attention is restricted to problems where strains remain small allowing for all aspects of material identification and associated computational treatment, developed for small-strain elastoplastic models, to be transferred easily to the present elasto-plastic thin-shell model. A finite element formulation is based on the four-noded isoparametric element. A particular attention is devoted to the consistent linearization of the shell kinematics and elasto-plastic material model, in order to achieve quadratic rate of asymptotic convergence typical for the Newton-Raphson-based solution procedures. To illustrate the main objective of the present approach-namely the simulation of failures of thin elastoplastic shells typically associated with buckling-type instabilities and/or bending-dominated shell problems resulting in formation of plastic hinges-several numerical examples are presented, Numerical results are compared with the available experimental results and representative numerical simulations
Two stress update algorithms for large strains: accuracy analysis and numerical implementation

Two algorithms for the stress update (i.e., time integration of the constitutive equation) in large-strain solid mechanics are compared from an analytical point of view. The order of the truncation error associated to the numerical integration is deduced for each algorithm a priori, using standard numerical analysis. This accuracy analysis has been performed by means of a convected frame formalism, which also allows a unified derivation of both algorithms in spite of their inherent differences. Then the two algorithms are adapted\ud
from convected frames to a fixed Cartesian frame and implemented in a small-strain finite element code. The implementation is validated by means of a set of simple deformation paths (simple shear, extension, extension and compression, extension and rotation) and two benchmark tests in non-linear mechanics (the necking of a circular bar and a shell under ring loads). In these numerical tests, the observed order of convergence is in very good agreement with the theoretical order of convergence, thus corroborating the accuracy analysis.Peer ReviewedPostprint (author’s final draft
ALE stress update for transient and quasistatic processes

A key issue in Arbitrary Lagrangian-Eulerian (ALE) non-linear solid mechanics is the correct treatment of the convection terms in the constitutive equation. These convection terms, which reflect the relative motion between the finite element mesh and the material, are found for both transient and quasistatic ALE analyses. It is shown in this paper that the same explicit algorithms can be employed to handle the convection terms of the constitutive equation for both types of analyses. The most attractive consequence of this fact is that a quasistatic simulation can be upgraded from Updated Lagrangian (UL) to ALE without significant extra computational cost. These ideas are illustrated by means of two numerical examples.Peer ReviewedPostprint (author’s final draft
On-line estimation of biomass through pH control analysis in aerobic yeast fermentation systems

The amount of acid or base consumed in yeast
cultures has been recently assigned to the pathway of
nitrogen assimilation under respiratory conditions with
no contribution by carbon metabolism (Castrillo et al.,
1995). In this investigation, experiments under respirofermentative
conditions have shown that production or
consumption of ethanol does not contribute significantly
to the specific rate of proton production (qH+), thus extending
the previously obtained relationships for all
aerobic conditions in which other major acid/base contributions
are not involved. Tests in batch and chemostat
culture confirm the validity of qH+ as a formal control
parameter in aerobic fermentations.Junta Nacional de Investigação Científica e Tecnológica

Gobierno Vasco (Departamento de Educación, Universidadese Investigación)

Ministerio de Educación y Ciencia-Acciones Integrada
Continuous ethanol fermentation of lactose by a recombinant flocculating saccharomyces cerevisiae strain

Alcohol fermentation of lactose was investigated
using a recombinant flocculating Saccharomyces
cerevisiae, expressing the LAC4 (coding for b-galactosidase)
and LAC12 (coding for lactose permease) genes of
Kluyveromyces marxianus. Data on yeast fermentation
and growth on a medium containing lactose as the sole
carbon source are presented. In the range of studied lactose
concentrations, total lactose consumption was observed
with a conversion yield of ethanol close to the
expected theoretical value. For the continuously operating
bioreactor, an ethanol productivity of 11 g L−1 h−1
(corresponding to a feed lactose concentration of 50 g
L−1 and a dilution rate of 0.55 h−1) was obtained, which is
7 times larger than the continuous conventional systems.
The system stability was confirmed by keeping it in operation
for 6 months.Instituto de Biotecnologia e Química Fina (IBQF) - Fundação  para a Ciência e a Tecnologia (FCT) -  PRAXISXXI/BD/11306/9
Contamination of a high-cell-density continuous bioreactor

Continuous fermentations were carried out
with a recombinant flocculent Saccharomyces cerevisiae
strain in an airlift bioreactor. Once operating under
steady state at a dilution rate of 0.45 h−1, the bioreactor
was contaminated with Escherichia coli cells. The faster
growing E. coli strain was washed out of the bioreactor
and the recombinant, slower growing flocculating S. cerevisiae
strain remained as the only species detected in
the bioreactor. Flocculation, besides allowing for the realization
of high-cell-density systems with corresponding
unusual high productivity, may be used as a selective
property for controlling some contamination problems
associated with prolonged continuous operation.Fundação para a Ciência e Tecnologia -PRAXIS XXI/BD/11306/97
Women fare no worse than men 10 years after attempted coronary angioplasty.

A retrospective review of cardiac events occurring in all patients who underwent attempted coronary angioplasty in the first 5 years of our experience (1980-1985) was undertaken. Follow-up data were obtained from the civil registry, hospital records, patient, family, and referring physician. Patient survival curves were constructed and the outcome of women and men was compared. Eight hundred fifty-six patients, 172 women and 684 men with a mean age of 60.0 and 55.3 years, respectively, underwent attempted coronary angioplasty with an overall procedural success rate of 82%, 77.7% in women and 83.1% in men. Follow-up data were obtained in 837 patients (97.8%) with a mean period of 9.6 years (range 0-13.3 years).

The estimated 10 year survival in women was identical to men [79%, 95% confidence interval (CI) 72.6–85.4% vs. 78%, 95% CI 74.6–81.4%] as was the 10 year event-free survival (men 36%, 95% CI 32.0–40.0% vs. women 37%, 95% CI 29.2-44.8%), with a similar proportion of major cardiac events—death, myocardial infarction, coronary artery bypass surgery, and repeat angioplasty. When women were matched to men for age and previous myocardial infarction, factors found to be associated with an adverse outcome, there was no significant difference. Additionally, outcome was compared after patients were matched for maximum nominal balloon size as an estimate of vessel size, with no significant difference between women and men. At follow-up, women complained of significantly more anginal symptoms than men (59.2% vs. 44.0%, P < 0.05) and took significantly more antianginal medication
Identification of nuclei from apoptotic, necrotic, and viable lymphoid cells by using multiparameter flow cytometry

Background: Methods widely used to detect apoptosis do not allow us to easily distinguish between nuclei from viable or necrotic cells. Even if apoptosis and necrosis seem to occur as alternatives at the single cell level, they could be present simultaneously in a cell population much more frequently than expected. For this reason, attention was focused on attempting to recognize, by multiparameter flow cytometry, the characteristics of viable cells and of apoptotic or necrotic dead cells. Methods: Apoptosis and necrosis were induced in vitro in murine thymocytes and lymphocytes from adult peripheral blood by using dexamethasone or prostaglandin E2 treatment and heat shock at 60Â°C or hydrogen peroxide, respectively. Traditional methods, such as DNA gel electrophoresis and propidium iodide staining followed by single-fluorescence analysis or annexin-V-fluorescein isothiocyanate plus propidium iodide staining by using flow cytometry, were compared with a new method. This method consisted of combined light-scatter and red fluorescence analysis by flow cytometry after isolation of nuclei by hypotonic solution as well as high-dose detergent treatment and DNA staining with propidium iodide. Results: Results showed that, although traditional methods such as DNA-gel electrophoresis and single-parameter fluorescence flow cytometry analysis were unable, as expected, to discriminate among viability, apoptosis, and necrosis, our new method has enabled us to easily identify nuclei from viable. apoptotic, and necrotic cells. Results obtained by using our method were comparable to those obtained by using two-color analysis of cells after propidium iodide/annexin V staining. Conclusions: A highly reproducible, inexpensive, rapid, and easily accessible method of analysis has been developed for simultaneously detecting apoptosis and necrosis
Augmented Lagrangian method and open boundary conditions in 2D simulation of Poiseuille-Bénard channel flow

The main objective of this study is to compare the influence of different boundary conditions upon the incompressible Poiseuille –Bénard channel flow (PBCF) in a 2D rectangular duct heated from below. In a first technical part the algorithm used to carry out this work, based on the augmented Lagrangian method, is presented. The implementation details of the five different open boundary conditions (OBCs) and the periodic boundary conditions (PBCs) tested in the present paper are also given. The study is then carried out for 1800<Ra≤ 10,000, 0<Re≤10 and 0·67≤Pr≤6·4. The five selected OBCs, applied at the outlet of the computational domain, respectively express the following conditions: a square profile for the velocity (OBC1), mass conservation (OBC2), zero second derivative of the horizontal velocity component (OBC3), a mixed boundary condition combining Dirichlet and Neumann conditions (OBC4) and an Orlanski‐type boundary condition (OBC5). A good estimation of the perturbation amplitude and of the length of the perturbed zone at the outlet boundary is proposed. It is shown that OBC5 causes very little perturbation in the recirculating flow compared with the other OBCs
Glycine increases the number of somatostatin receptors and somatostatin-mediated inhibition of the adenylate cyclase system in the rat hippocampus

The glycine and somatostatin (SS) neurotransmission systems in the brain have been implicated in the function of sensory, motor, and nociceptive pathways. To investigate a possible relationship between these two components, we studied the influence of glycine on the binding of 125I-Tyr11-SS to its receptors and on SS-like immunoreactivity (SSLI) levels in the rat hippocampus and frontoparietal cortex. An intracerebroventricular (i.c.v.) dose of 16 or 160 nmol of glycine induced an increase in the total number of specific SS receptors in the hippocampus but not in the frontoparietal cortex at 15 min following injection, with no changes in the affinity constant. This effect seems to be mediated by inhibitory strychnine-sensitive glycine receptors since pretreatment with the antagonist strychnine (80 μg/100 g body weight, intravenously) abolished this response. No significant changes in SSLI content were detected in either brain region of glycine- and strychnine plus glycine-treated rats as compared to control values. Since SS receptors are coupled via guanine nucleotide-binding G proteins to the adenylyl cyclase (AC) system, we also examined the inhibitory effects of SS and the guanine nucleotide Gpp(NH)p on AC activity in hippocampal membranes of control, glycine- and strychnine plus glycine-treated rats since the increase in SS receptors was observed only in this brain area. No significant differences were observed for the forskolin (FK)-stimulated AC enzyme activities in hippocampal membranes from all the experimental groups studied. In the hippocampus of the glycine-(160 nmol) treated group, however, basal AC activity was significantly lower, and the capacity of SS to inhibit FK-stimulated AC activity was increased as compared to the control group. Pretreatment with strychnine prevented the increase in SS-mediated inhibition of AC activity. The functional activity of the inhibitory guanine nucleotide-binding protein G1, as determined by the inhibitory effect of the stable GTP analogue Gpp(NH)p on FK-stimulated AC activity, was significantly higher in hippocampal membranes of glycine- (160 nmol) treated rats as compared to controls. This suggests that the increased inhibition of AC activity by SS in the glycine-treated group may be due to the increase in G1 activity and/or the increase in the number of SS receptors observed. Alternatively, the greater G1 activity may be responsible for the increased binding of 125I-Tyr11-SS to its receptors observed after glycine administration. Altogether, these data suggest that the hippocampal somatostatinergic system can be regulated by strychnine-sensitive glycine receptors in the rat. © 1996 Wiley-Liss, Inc.This work was supported by a grant from the Dirección General de Investigación Científica y Técnica of Spai
Ethnomethodologically informed ethnography and information system design

This paper describes ethnomethodologically informed ethnography (EM) as a methodology for information science research, illustrating the approach with the results of a study in a university library. We elucidate major differences between the practical orientation of EM and theoretical orientation of other ethnographic approaches in information science research. We address ways in which EM may be used to inform systems design and consider the issues that arise in coordinating the results of this research with the needs of information systems designers. We outline our approach to the “ethnographically informed” development of information systems in addressing some of the major problems of interdisciplinary work between system designers and EM researchers.British Library Research and Innovation Centrepublished or submitted for publicationis peer reviewe
Kinetics of oxidation of indigo carmine by N-sodio-N-bromotoluenesulfonamide in acidic buffer medium

The kinetics of oxidation of indigo carmine (IC) by N-sodio-N-bromotoluenesulfonamide or bromamine-T (BAT) in pH 5 buffer medium has been investigated at 30 degrees C using spectrophotometry at 610 nm. The reaction rate shows dependencies of first-order on [IC](0), second-order on [BAT](0) fractional order on [H+], and inverse first-order on [p-toluenesulfonamide]. The addition of chloride and bromide ions, and the variation of ionic strength of the medium have no influence on the reaction rate. There is a negative effect of the dielectric constant of the solvent. Activation parameters have been calculated. A single-pathway mechanism for the reaction, consistent with the kinetic data, has been proposed. (C) 1997 John Wiley & Sons, Inc
Kinetic and mechanistic study of oxidation of diethylamine by N-sodio-N-bromobenzene sulphonamide (bromamine-B) in acid solution: Catalyzed by Ru(III)

Kinetics of oxidation of diethylamine (DEA) by Bromamine-B (BAB) has been investigated at 303 K in acid solution with Ru(III) as catalyst. The oxidation behavior obeys the rate law, rate = k BAB] DEA] Ru(III)] H+](-x) where `x' is less than unity indicating retardation of rate by H+]. Added halide ions, the reaction product benzenesulphonamide, variation of ionic strength and dielectric constant of the medium do not have any significant effect on the rate. The protonation constant of monobromamine-B evaluated for the reaction is 32.3 at 303 K. Activation parameters have been evaluated from Arrhenius plot. A mechanism consistent with experimental results has been proposed. (C) 1999 John Wiley & Sons, Inc
Effect of evaporation time on the pervaporation characteristics through homogeneous aromatic polyamide membranes. II. Pervaporation performances for ethanol/water mixture

Pervaporation of ethanol/water mixtures through symmetric dense aromatic polyamide membranes was investigated. The membrane structure was controlled by varying the solvent evaporation time before gelation. The membranes were water-selective and the selectivity increased with an increase in the solvent evaporation time. On the other hand, the water flux as well as the ethanol flux decreased with an increase in the evaporation time. These results were consistent with the morphology change of the membrane which takes place with solvent evaporation: the decrease in the channel size. The effects of the downstream pressure on the pervaporation performances were also studied for membranes with different solvent evaporation times. the ethanol concentration in the permeate side increased with an increase in the downstream pressure to certain point, showed a maximum there, then decreased thereafter. The water flux decreased with an increase in the downstream pressure for all membranes studied; the dependence was expressed by a parabolic curve in the lower pressure range. The ethanol flux also decreased with an increase in the downstream pressure for the membrane with shorter evaporation time, while this flux was slightly affected by the downstream pressure for the membrane with longer evaporation time.Peer reviewed: YesNRC publication: Ye
Electropolymerization of trimethylsilylphenols to silylated polyphenylene oxides and investigation of their properties. Enhanced conductivity of PPO by silyl group

Polymerization of o-, m-, and p-trimethylsilylphenols (TMS-phenols) was achieved electrochemically. The polymers were prepared as thin films on a platinum electrode and were found to be electroinactive in nonaqueous solutions. The polymers exhibited far higher conductivities than polyphenol or other substituted polyphenols. The conductivity of poly (p-TMS-phenol) was lower than that observed for the polymers of the o- and m-isomers. The polymers were characterized by infrared spectroscopy. The effect of monomer concentration, supporting electrolyte concentration, current densities, and temperature on the poymerization was investigated using microgravimetry. The observed empirical kinetics were as follows. The rates of polymerization of o-, m-, and p-TMS-phenol were found to be of 0.8, 0.8, and 0.7 order dependent on monomer concentation, of 0.5, 0.5 and 0.45 order dependent on electrolyte concentration, and of 0.9, 0.9 and 0.8 order dependent on current densities. By investigating the effect of temperature on electropolymerization, the corresponding activation energies of electropolymerization were calculated to be 0.9, 0.9, and 0.8 kj/mole. The molecular weights of poly(o-TMS-phenol) and poly(m-TMS-phenol) were determined by gel permeation chromotography. © 1997 John Wiley & Sons, Inc
Effect of prereaction on curing of elastomer-modified epoxy resins

Three multifunctional epoxy resins novolac epoxy (EPN), triglycidyl paraaminophenol (TGPAP), and tetraglycidyl diaminodiphenylmethane (TGDDM) were modified with a carboxy-terminated acrylate-based liquid elastomer (PnBA). The effect of prereaction of the epoxy groups in the resin and carboxyl group in the elastomer on curing parameters, such as the cure reaction conversions; processing parameters, such as gel times and vetrification times; initial cure temperatures, and activation energy values were evaluated. Fourier transform infrared spectrometry (FTIR), dynamic mechanical spectrometry (DMS), and differential scanning calorimetry (DSC) were used for the study. The results indicated that while the cure reactions were slightly retarded in the presence of elastomer, they were slightly accelerated when certain prereaction catalysts were used. The gel times and vitrification times decreased due to the prereaction. The physical properties such as fracture toughness and modulus of neat resin castings and flexural strength properties of carbon cloth-reinforced laminates were evaluated. Results indicated that the toughness property increased and the modulus decreased with elastomer addition. © 1997 John Wiley & Sons, Inc
Staged and non-staged anaerobic filters : microbial activity segregation, hydrodynamic behaviour and performance

This work describes a comparative study of staged and non-staged anaerobic flters for treating a synthetic dairy waste under similar operating conditions.
The effect of increasing the substrate concentration from 3 to 12 g COD dmˉ³ at a constant hydraulic residence time (HRT) of 2 days was evaluated with
respect to overall reactor performance, biogas production, volatile fatty acids
profiles along the height, methanogenic and acidogenic activity distribution, and
hydrodynamic behaviour. The potential maximum specific methanogenic activity
against acetate, hydrogen, propionate and butyrate and the lactose specific activity
were determined for sludge sampled from three different points in each
reactor, under two operating conditions (influent COD of 3 and 9 g COD
dmˉ³). Although all trophic groups involved in the anaerobic process were
found throughout the reactors, it was possible to identify different specific
sludges at different heights in both reactors. Performances of the two configurations
were very similar under the operating conditions tested and the plug flow
behaviour of the staged reactor was clearly reduced when the influent concentration
increased from 3 to 9 g COD dmˉ³.Fundação para a Ciência e a Tecnologia – PEAM/SEL/517/95.EU Human Capital and Mobility network Improved Application of Anaerobic
Digestion Technology - EXBCHRXCT 930262