bluuebunny/crossref_metadata_2025_split huggingface dataset:
Levels of amino acid neurotransmitters during mouse olfactory bulb neurogenesis and in histotypic olfactory bulb cultures
Authors: Miranda‐Contreras L. , Ramı́rez‐Martens L.M. , Benı́tez‐Diaz P.R. , Peña‐Contreras Z.C. , Mendoza‐Briceño R.V. , Palacios‐Prü E.L. 
Published: July 2002

AbstractThe developmental changes in the levels of amino acid neurotransmitters were analyzed by high pressure liquid chromatography during mouse olfactory bulb neurogenesis, from embryonic day (E)13 until the young adult age, between postnatal days (P)30 and P40. During the embryonic period, high levels of glutamate, aspartate and GABA were observed, with the values of GABA about 2‐fold higher than those of glutamate and aspartate. At P0, the production of these neurotransmitters experienced birth stress as shown by a significant 2‐fold reduction in their levels. During the first two postnatal weeks, a progressive increase in the glutamate content was detected diminishing slightly in the adult stage. The aspartate concentrations showed a maximal value at P3 and then decreased gradually until the second postnatal week; in the young adult age, its concentration was comparable with that of glutamate. The postnatal GABA contents increased progressively from birth to maturity, showing maximal levels at P3, P11 and in the adult. Throughout the studied developmental period, the concentration of glycine remained relatively low. With regard to taurine, very low concentrations were detected during the prenatal period but after birth, the taurine content gradually increased with age, and in the adult animal, its concentration was comparable with those of GABA and glutamate. Our data demonstrate the predominance of GABA and glutamate during olfactory bulb synaptogenesis, however, in the adult animal, both glutamate and aspartate exert the same influence in the excitatory synaptic transmission; in the adult inhibitory synaptic transmission, taurine appears to play an important neuromodulatory or neurotransmitter role as that of GABA. To determine the intrinsic neurotransmitter production, primary histotypic olfactory bulb cultures were prepared from mice at P10. The comparative analysis of in vitro neurotransmitter contents with those in in situ adult animal showed higher levels of endogenously produced glutamate, glycine and GABA in the olfactory bulb than the extrinsic ones coming from olfactory nerve axons and higher olfactory brain centers. On the other hand, most of aspartate and taurine neurotransmitters apparently come from extrinsically located neurons.
Detoxification of Dilute Acid Hydrolysates of Lignocellulose with Lime
Authors: Martinez Alfredo , Rodriguez Maria E. , Wells Melissa L. , York Sean W. , Preston James F. , Ingram Lonnie O. 
Published: July 2002

AbstractThe hydrolysis of hemicellulose to monomeric sugars by dilute acid hydrolysis is accompanied by the production of inhibitors that retard microbial fermentation. Treatment of hot hydrolysate with Ca(OH)2 (overliming) is an effective method for detoxification. Using ethanologenic Escherichia coli LY01 as the biocatalyst, our results indicate that the optimal lime addition for detoxification varies and depends on the concentration of mineral acids and organic acids in each hydrolysate. This optimum was shown to be readily predicted on the basis of the titration of hydrolysate with 2 N NaOH at ambient temperature to either pH 7.0 or pH 11.0. The average composition of 15 hydrolysates prior to treatment was as follows (per L): 95.24 ± 7.29 g sugar, 5.3 ± 2.99 g acetic acid, 1.305 ± 0.288 g total furans (furfural and hydroxymethylfurfural), and 2.86 ± 0.34 g phenolic compounds. Optimal overliming resulted in a 51 ± 9% reduction of total furans, a 41 ± 6% reduction in phenolic compounds, and a 8.7 ± 4.5% decline in sugar. Acetic acid levels were unchanged. Considering the similarity of microorganisms, it is possible that the titration method described here may also prove useful for detoxification and fermentation processes using other microbial biocatalysts.
Olive Oil Mill Waste Waters Decoloration and Detoxification in a Bioreactor by the White Rot Fungus Phanerochaeteflavido‐alba
Authors: Blánquez P. , Caminal G. , Sarrà M. , Vicent M. T. , Gabarrell X. 
Published: July 2002

AbstractOlive oil mill wastewater (OMW) is produced as waste in olive oil extraction. With the purpose of treating this highly polluting waste, a number of experiments were conducted in a laboratory‐scale bioreactor with the white rot fungus Phanerochaete flavido‐alba ( P. flavido‐alba). It is known that this fungus is capable of decolorizing OMW in static or semistatic cultures at Erlenmeyer scale and at 30 °C. The objective of this work was to prove that P. flavido‐alba could decolorize OMW in submerged cultures and that it is capable of reducing OMW toxicity at room temperature (25 °C) and in a laboratory‐scale bioreactor. In the experiments conducted, manganese peroxidase (MnP) and laccase enzymes were detected; however, unlike other studies, lignin peroxidase was not found to be present. Decoloration obtained after treatment was 70%. The reduction of aromatic compounds obtained was 51%, and the toxicity of the culture medium was reduced by up to 70%. We can therefore state that P. flavido‐alba is capable of reducing important environmental parameters of industrial effluents and that prospects are positive for the use of this process at a larger scale, even when working at room temperature.
Computational Fluid Dynamics Model for Predicting Flow of Viscous Fluids in a Large Fermentor with Hydrofoil Flow Impellers and Internal Cooling Coils
Authors: Kelly William J. , Humphrey Arthur E. 
Published: July 2002

AbstractConsiderable debate has occurred over the use of hydrofoil impellers in large‐scale fermentors to improve mixing and mass transfer in highly viscous non‐Newtonian systems. Using a computational fluid dynamics software package (Fluent, version 4.30) extensive calculations were performed to study the effect of impeller speed (70–130 rpm), broth rheology (value of power law flow behavior index from 0.2 to 0.6), and distance between the cooling coil bank and the fermentor wall (6–18 in.) on flow near the perimeter of a large (75‐m3) fermentor equipped with A315 impellers. A quadratic model utilizing the data was developed in an attempt to correlate the effect of A315 impeller speed, power law flow behavior index, and distance between the cooling coil bank and the fermentor wall on the average axial velocity in the coil bank−wall region. The results suggest that there is a potential for slow or stagnant flow in the coil bank−wall region which could result in poor oxygen and heat transfer for highly viscous fermentations. The results also indicate that there is the potential for slow or stagnant flow in the region between the top impeller and the gas headspace when flow through the coil bank−wall region is slow. Finally, a simple guideline was developed to allow fermentor design engineers to predict the degree of flow behind a bank of helical cooling coils in a large fermentor with hydrofoil flow impellers.
Pilot‐Scale Purification of Zeamatin, an Antifungal Protein from Maize
Authors: Wilson Shelly , Mahiou Belaid , Reiger Robert , Tentler Sangita , Schimoler Rebecca , Orndorff Steve , Selitrennikoff Claude P. 
Published: July 2002

AbstractZeamatin is an antifungal protein isolated from the seeds of Zea mays. A practical process for isolation and purification was developed to increase recovery yields for future testing of zeamatin as a novel therapeutic drug. Zeamatin was extracted with buffer from corn meal milled to flour. Solids were removed from the extract using pressure filtration, and zeamatin was purified using two separate reverse‐phase chromatography steps. Determination of the amino‐terminal amino acid sequence, Western blotting using anti‐zeamatin antibody, and activity against Candida albicans were used to confirm that the purified protein was zeamatin. From 5 kg of corn meal, ∼110 mg of zeamatin was purified to apparent homogeneity.
Improving student learning in root canal treatment using self‐assessment
Authors: Manogue M. , Brown G. A. , Nattress B. R. , Fox K. 
Published: July 2002

Aim This paper reports the first attempts to implement a new course in endodontology for undergraduate dental students based upon independent, reflective learning and self‐ assessment.Methodology The responses were analysed of two successive cohorts of third‐year students to laboratory courses in (i) the restoration of teeth with crowns and (ii) endodontology and root canal treatment. The major changes introduced to the endodontology course were a substantial reduction in the number of formal lectures, the introduction of a series of structured tutorials, time for private study and the use of self‐assessment in practical classes.Results The evidence indicates that the new approach increased student confidence in practical skills, although the time available for operative practice was actually reduced; there was a perceived increase in problem‐solving ability; and that students felt encouraged to pursue greater understanding. Reports from tutors suggested that students’ self‐assessments became more accurate as the courses proceeded. Seven experiential learning points were derived from the study. These included the importance of careful planning, well‐designed assessment procedures and the creation of a climate of trust and openness.Conclusions The task of developing fully the students’ skills of accurate self‐assessment remains a challenge.
Effects of oxide traps, interface traps, and ‘‘border traps’’ on metal-oxide-semiconductor devices
Authors: Fleetwood D. M. , Winokur P. S. , Reber R. A. , Meisenheimer T. L. , Schwank J. R. , Shaneyfelt M. R. , Riewe L. C. 
Published: July 2002

We have identified several features of the 1/f noise and radiation response of metal-oxide-semiconductor (MOS) devices that are difficult to explain with standard defect models. To address this issue, and in response to ambiguities in the literature, we have developed a revised nomenclature for defects in MOS devices that clearly distinguishes the language used to describe the physical location of defects from that used to describe their electrical response. In this nomenclature, ‘‘oxide traps’’ are simply defects in the SiO2 layer of the MOS structure, and ‘‘interface traps’’ are defects at the Si/SiO2 interface. Nothing is presumed about how either type of defect communicates with the underlying Si. Electrically, ‘‘fixed states’’ are defined as trap levels that do not communicate with the Si on the time scale of the measurements, but ‘‘switching states’’ can exchange charge with the Si. Fixed states presumably are oxide traps in most types of measurements, but switching states can either be interface traps or near-interfacial oxide traps that can communicate with the Si, i.e., ‘‘border traps’’ [D. M. Fleetwood, IEEE Trans. Nucl. Sci. NS-39, 269 (1992)]. The effective density of border traps depends on the time scale and bias conditions of the measurements. We show the revised nomenclature can provide focus to discussions of the buildup and annealing of radiation-induced charge in non-radiation-hardened MOS transistors, and to changes in the 1/f noise of MOS devices through irradiation and elevated-temperature annealing.
Border-trap densities of ∼1010–1011 cm−2 are inferred from changes in switching-state density during postirradiation annealing, and from a simple trapping model of the 1/f noise in MOS devices. We also present a detailed study of charge buildup and annealing in MOS capacitors with radiation-hardened oxides through steady-state and switched-bias postirradiation annealing. Trapped-hole, trapped-electron, and switching-state densities are inferred via thermally stimulated current and capacitance-voltage measurements. A lower bound of ∼3×1011 cm−2 is estimated for the effective density of border traps that contribute to the electrical response of the irradiated devices. This is roughly 20% of the observed switching-state density for these devices and irradiation conditions. To our knowledge, this represents the first quantitative separation of measured switching-state densities into border-trap and interface-trap components. Possible physical models of border traps are discussed. E′ centers in SiO2 (trivalent Si centers associated with oxygen vacancies) may serve as border traps in many irradiated MOS devices.
Nuclear magnetic resonance relaxivity and surface-to-volume ratio in porous media with a wide distribution of pore sizes
Authors: Borgia G. C. , Brown R. J. S. , Fantazzini P. 
Published: July 2002

The simplest model for the contribution of pore surfaces to nuclear magnetic resonance (NMR) relaxation of a pore fluid gives R, the average relaxation rate minus the bulk rate, equal to a constant ρ, the velocity at which nuclear magnetization flows out of the pore fluid at the surfaces, times the pore-space surface-to-volume ratio S/V. Although ρ can vary widely, a great variety of porous media exhibit ρ values of the order of a few μm/s for longitudinal relaxation when S/V is measured by gas adsorption by the Brunauer, Emmett, and Teller (BET) method or high pressure mercury injection. For samples with wide distributions of relaxation rates it is of interest to find what functions of the relaxation data correlate best with S/V measurements and how different relaxation parameters relate to each other. Longitudinal relaxation data were taken for 77 sandstone samples of different origin, which had been cleaned and saturated with brine. After the NMR measurements the samples were dried and surface areas measured by BET. The samples have S/V from 1.5 to 150 (μm)−1, porosity from 3% to 28%, and permeability from less than 0.1 mD to more than 1 D. Longitudinal relaxation data were taken from 400 μs to 6 s and analyzed in many different ways, including stretched-exponential fits and multiexponential fits up to five components. S/V and ln(S/V) were correlated with various relaxation rates derived from these computed parameters.
In principle, the relaxation parameter to use with a ρ value is the average rate, which is initial slope divided by initial amplitude, namely, R(0), where R(t)=(d/dt)ln S(t) at t=0 and S(t) is the relaxing signal. One can extrapolate an n component fit to t=0 to get Rn(0), but very good signal quality is required even to get small short components reliably for t well within the times covered by the data. Over half of the points have ρ’s within a factor of 2 of the minimum value 0.9 μm/s when the average rate of a five-component fit to the data is used. There are numerous points with ρ up to 7 μm/s, but none of the high-ρ points are for samples with high S/V. All samples with high S/V have wide distributions of relaxation rates, but not vice versa. The best simple correlation with ln(S/V) was ln(S/V)≊1.81 ln(R33)−5.73, where R33 is the highest rate of a three-component fit without regard to the corresponding amplitude, and where S/V is in (μm)−1 and rate in s−1. This result was unexpected. This fit does not represent proportionality to a velocity ρ and does not correspond to any obvious physical model, but it can be of practical interest to estimate in a very simple and noninvasive manner S/V at the BET scale in sandstones.
Association of nonionic polymers with micelles, bilayers, and microemulsions
Authors: Nagarajan R. 
Published: July 2002

A unified thermodynamic theory is developed here to explore the nature of association of nonionic polymer molecules with surfactant aggregates such as globular micelles, rod-like micelles, bilayers, oil in water microemulsions, and water in oil microemulsions. The association complex is visualized as consisting of the polymer molecule wrapped around the aggregate at its interface with water. The association with polymer provides enhanced shielding of the hydrophobic aggregate surface from water, increases the steric repulsions at the aggregate surface and gives rise to hydrophobic interactions between the polymer and the aggregate surface. Simple free energy models are formulated to account for these polymer-induced effects. Illustrative calculations have been carried out to examine the behavior of monoalkyl and dialkyl surfactants with nonionic, anionic, and zwitterionic polar head groups. The results show that polymer–aggregate association is almost always preferred in the case of anionic or zwitterionic surfactants. As a result of the association with the polymer, globular micelles transform into smaller globular micelles; large, polydisperse rod-like micelles change into small, monodispersed globular micelles; spherical vesicles and planar bilayers transform into smaller discoids. In all the cases, the polymer-bound aggregates are formed at a critical micelle concentration (CMC) that is significantly lower than the CMC of the polymer-free systems. In marked contrast, aggregates of nonionic surfactants may or may not associate with the polymer molecule. If association occurs, the polymer-induced changes in the aggregate morphologies are similar to those for the anionic surfactants. However, the CMC for the formation of bound aggregates is usually very close to that for the formation of the free aggregates. In many situations, association is not favored and polymer-free aggregates coexist with free polymer molecules in solution. It is found that subtle variations in the hydrophobic characteristics of the polymer molecule can tilt the equilibrium between polymer-bound and polymer-free aggregates. In the case of microemulsions, calculations show that the volume ratio of the dispersed phase to the surfactant is significantly altered by the presence of the polymer. Also,
the condition for phase inversion from oil in water to water in oil type of microemulsion is modified by the presence of the polymer. The theoretical results suggest ways by which one may control the morphologies of surfactant aggregates using polymer additives.
Contextual Influence On The Language Production Of Children With Speech/Language Impairment
Authors: Hansson Kristina , Nettelbladt Ulrika , Nilholm Claes 
Published: July 2002

AbstractTo investigate the possible contextual variability of language and interaction, data from 10 children with speech/language impairment and three different types of conversational partners (a parent, a peer and a clinician) were collected. The dialogues were analysed with respect to the characteristics of the dialogues as wholes, to the dominance and the productivity of the three types of conversational partners, and to the productivity, fluency and grammatical structure of the language production of the children with speech/language impairment. Productivity was measured as mean length of utterance (MLU) in words, number of utterances, number of different words and proportion of complete and intelligible utterances. Fluency was measured as the proportion of utterances containing a maze. Grammatical structure was analysed with respect to the use of grammatical morphemes, word order patterns, the occurrence of expansions and the complexity of verb forms. Significant differences, in particular between child‐child and adult‐child dialogues were found. The adult‐child dialogues were asymmetrical, where the adults dominated through asking many questions and talking much. The peer dialogues were more dynamic and equal. In these dialogues the children with speech/language impairment took a more active role as a conversational partner. The children produced more utterances and different words with the adult partners, but variables related to fluency and grammatical structure did not vary as a function of the conversational partner. The results imply that children with speech/language impairment practise different aspects of their communicative ability with different types of conversational partners. In particular, it is important to provide them with opportunities to interact with peers, in order for them to develop their skills as independent conversational partners.
Phonological awareness therapy and articulatory training approaches for children with phonological disorders: a comparative outcome study
Authors: Hesketh Anne , Adams Catherine , Nightingale Catherine , Hall Rebecca 
Published: July 2002

AbstractSixty‐one children, aged 3;6‐5;0, with developmental phonological disorders (PD) participated in a study comparing the effects of metaphonologically (MET) or articulation‐based (ART) therapy. Maturational effects were controlled for by the inclusion of 59 normally speaking control children of the same age range. Measures of phonological (speech) output and phonological awareness were taken before and after therapy for all subjects and at 3 months post‐therapy for PD children. Results showed that PD children improved significantly in both phonological output and awareness skills across the intervention period compared with control children, but that there was no significant difference on the awareness measure between ART and MET groups. ART and MET groups differed from each other on one measure of speech improvement only, with the ART group making more change than the MET group on individual probe scores. Follow‐up measures for both therapy groups indicated that there was little difference between the groups on phonological awareness change or speech development 3 months after intervention, though there was a trend for MET children to continue to make more long‐term change than the ART group on one output measure. Additional analysis showed that there were generally few significant implications for outcome between PD children with good initial phonological awareness skills and those who initially had poor phonological awareness skills.
Universities and article copyright
Authors: Law D. G. , Weedon R. L. , Sheen M. R. 
Published: July 2002

ABSTRACTThe advent of electronic publishing raises many questions about the exercise of digital rights. We examine the problem of who owns the copyright of articles in the context of university attitudes to intellectual property generally and evolving practices in the publishing arena. We conclude that the balance between author and publisher is changing and that universities, as employers, could play a larger part in shifting the balance still further.
Pragmatic citing and linking in electronic scholarly publishing
Authors: Doyle Mark 
Published: July 2002

ABSTRACTThe transition from traditional, paper‐based publishing to electronic publishing presents many challenges for publishers and their constituents. Among the most significant are those that concern linking to articles that are available online and citing of articles that are now published online prior to (or even in lieu of) the final pagination and binding of paper issues. The solutions to these problems will have a great impact on the usability of the scholarly electronic corpus for the research community. In particular, the solutions must be easy to use, persistent, and scalable. Here we examine some pragmatic solutions (in use now) that satisfy these criteria and contrast them with other proposed solutions. The examples are drawn mainly from the experiences of the American Physical Society, but the lessons gleaned will have wide applicability.
Library purchasing consortia: the UK periodicals supply market
Authors: Ball David , Pye Jo 
Published: July 2002

ABSTRACTThis article is based on surveys undertaken for a British Library Research and Innovation Centre/Library and Information Commission‐funded research project. It describes the models of operation of purchasing consortia in two library sectors (health and higher education) and their expenditure patterns. Present and future savings deriving from consortial activity and the effects of consortia on periodicals suppliers are discussed. The article closes by predicting future activity.