bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitric Oxide Inhibits Stretch-Induced MAPK Activation in Mesangial Cells Through RhoA Inactivation
Authors: Krepinsky Joan C. , Ingram Alistair J. , Tang Damu , Wu Dongcheng , Liu Lieqi , Scholey James W.
Published: October 2004

Glomerular capillary hypertension is an important determinant of glomerulosclerosis in rats with subtotal renal ablation. Dietary supplementation with L-arginine increases renal nitric oxide (NO) production and limits glomerular injury in this model, and early benefits are seen without altered glomerular capillary pressure. In an in vitro model of hemodynamically mediated signaling, the authors have reported that subjecting MC to cyclic stretch/relaxation activates the mitogen-activated protein kinase p42/44 (Erk) cascade and that NO and cyclic GMP abrogate stretch-induced Erk activation by inducing actin cytoskeletal disassembly. The actin cytoskeleton is regulated by the Rho family of GTPases, including RhoA; therefore, the authors examined the role of RhoA in stretch-induced Erk activation and as an NO target. In primary rat MC subjected to cyclic mechanical strain, RhoA activity was maximally increased (2.4-fold) after 1 min of stretch, and Erk activation temporally followed. The Rho-kinase inhibitor Y-27632 attenuated Erk activation in a dose-dependent manner and prevented stretch-induced actin stress fiber formation. The NO donors S-nitroso-N-acetylpenicillamine and cGMP both inhibited stretch-induced RhoA and Erk activation and stress fiber formation. Infection of MC with the RhoA mutant RhoA-Ala188, which is resistant to NO-dependent phosphorylation, abrogated the effects of NO and cGMP on stretch-induced Erk activation and stress fiber formation. The authors conclude that the early activation of RhoA is essential for stretch-induced actin stress fiber formation and Erk activation in MC, events which are prevented by NO and cGMP through their action on RhoA. Inhibition of RhoA may thus be a new approach to the prevention of hemodynamically mediated glomerular injury. E-mail: krepinj@mcmaster.ca
Reversal of Glomerulosclerosis after High-Dose Enalapril Treatment in Subtotally Nephrectomized Rats
Authors: Adamczak Marcin , Gross Marie-Luise , Krtil Jan , Koch Andreas , Tyralla Karin , Amann Kerstin , Ritz Eberhard
Published: October 2004

Interventions to block the renin-angiotensin system (RAS) halt the progression of renal lesions in renal damage models. It has recently also been reported that established glomerulosclerosis can be reversed by pharmacologic blockade of the RAS. It was the aim of this study to confirm that high doses of angiotensin-converting enzyme (ACE) inhibitors reverse established glomerulosclerosis and to extend the findings by providing quantitative information on glomerular geometry, podocytes and other glomerular cells, renal vessels and tubulointerstitial tissue. Male Sprague Dawley rats were subjected to subtotal surgical renal ablation (SNX) (n = 27) or sham operation (n = 31) and fed using a pair-feeding protocol. Eight weeks after surgery, rats were either sacrificed or allocated to two arms: enalapril treatment (48 mg/kg body wt per day administered in the drinking fluid for 4 wk) or no treatment. Renal morphology was evaluated after 8 or 12 wk, respectively, by stereology in tissue fixed by pressure-controlled perfusion. Both systolic BP and albumin excretion rate were significantly higher in SNX compared with sham-operated controls. They were significantly reduced in SNX after delayed enalapril treatment. The glomerulosclerosis (GSI), tubulointerstitial (TII), and vascular (VI) damage indices were significantly higher in all SNX groups than in sham-operated controls. At the end of the experiment (12 wk after SNX) GSI, TII, and VI were significantly lower in SNX with delayed enalapril treatment (0.77 ± 0.18, 0.63 ± 0.19 and 0.43 ± 0.16, respectively) compared with untreated SNX (1.64 ± 0.14, 1.16 ± 0.34 and 0.67 ± 0.29, respectively). GSI, TII, and VI were also significantly lower in SNX with delayed enalapril treatment compared with SNX sacrificed without treatment 8 wk after SNX. The same was true for glomerular volume. The number of podocytes was not affected by SNX, but podocyte volume was increased. Both indices remained unaffected by treatment. The numbers of cells within the mesangium and endothelial cells per glomerulus were significantly lower in SNX after delayed enalapril treatment compared with untreated SNX. These results strongly suggest regression of preexisting lesions, i.e., glomerular, tubular, and vascular remodeling as well as reversal of glomerular hypertrophy by ACE inhibitor treatment. The study confirms that high-dose ACE inhibitor treatment causes partial reversal of glomerular as well as interstitial lesions in subtotally nephrectomized rats. E-mail: kerstin.amann@patho.imed.uni-erlangen.de
Long-Term Graft Survival with Neoral and Tacrolimus
Authors: Kaplan Bruce , Schold Jesse D. , Meier-Kriesche Herwig-Ulf
Published: October 2004

Calcineurin inhibitors (CNI) are an important component of most immunosuppressive protocols utilized in renal transplantation. Both CNI available (cyclosporine and tacrolimus) have been used for many years. Studies comparing the efficacy of these two agents in terms of long-term graft or patient survival have thus far failed to show an advantage for either agent. This failure to show a difference could possibly be due to underpowering of clinical trials. The authors used the SRTR database to analyze 5-yr graft survival of the microemulsion formulation of cyclosporine (Neoral) as compared with tacrolimus. To minimize the donor variability and bias, a paired kidney analysis was used. Deceased donors from the years 1995–2002 were analyzed from the SRTR database. All paired kidneys during this period, where one kidney was allocated to a patient receiving initial Neoral therapy and its mate allocated to a patient receiving initial tacrolimus therapy were evaluated. Multivariate and univariate analysis were performed. Univariate analysis demonstrated equivalent graft survival for Neoral compared with tacrolimus (66.9% versus 65.9%, respectively). Multivariate analysis could not demonstrate a difference in risk for 5-yr patient survival or graft loss. Renal function was superior for tacrolimus at all time points, whereas the slope of 1/Cr over time did not differ for the two agents. In this paired kidney analysis, no difference in 5-yr renal allograft survival could be found between the two agents. Renal function was superior in the patients receiving initial tacrolimus therapy; however, slope of 1/Cr did not differ between the agents. E-mail kaplab@medicine.ufl.edu
Divergence in replicated phylogenies: the evolution of partial post-mating prezygotic isolation in bean weevils
Authors: Fricke C. , Arnqvist G.
Published: October 2004

By tradition, speciation research has been focused on processes leading to either premating or post-zygotic reproductive isolation. The processes which generate isolation after mating but before zygote formation are less well understood. Here, we study divergence in characters which contribute to post-mating prezygotic isolation, such as egg production and remating rate. We propose that ‘replicated’ laboratory phylogenies with known histories can be used to yield insights into the processes of divergence. We performed a series of cross-matings between populations within two strains of the bean weevil Callosobruchus maculatus. Each strain has a unique and independent origin and both have been kept in the same set of laboratories during the last few decades. Our results show that divergence has occurred between laboratory populations within strains with regards to the effects that mating has on female reproductive behaviour, showing that the evolution of partial post-mating prezygotic isolation can be rapid. More importantly, the pattern of divergence across populations was distinct in the two strains, suggesting that coevolutionary trajectories are not determined by environmental factors but are to some extent arbitrary. We discuss the limitations of the novel empirical strategy employed here, and conclude that our results lend support to the hypothesis that post-mating sexual selection is capable of rapidly generating post-mating prezygotic isolation.
Evolution of viviparity in horned lizards (Phrynosoma): testing the cold-climate hypothesis
Authors: Hodges W. L.
Published: October 2004

The cold-climate hypothesis for evolution of viviparity in squamates predicts a correlation between reproductive mode, altitude and latitude. I tested this prediction in horned lizards within a phylogenetic context. I first determined whether all viviparous species were monophyletic using Monte Carlo simulations. Secondly, I tested for presence of phylogenetic signal using randomization tests. Thirdly, I analysed relationships between reproductive mode and minimum, midpoint, and maximum altitudes and latitudes by computing conventional correlations and phylogenetically independent contrasts. Viviparous species do not form a monophyletic group suggesting viviparity evolved twice in the genus. Viviparity and altitude showed strong phylogenetic signal based on randomization tests and were significantly correlated, while latitude was not correlated with reproductive mode. This study partially supports the cold-climate model, but also suggests that altitude either may be a better predictor of cold temperatures or may be a surrogate for other selective factors important in the evolution of viviparity.
The effect of temperature and wing morphology on quantitative genetic variation in the cricket Gryllus firmus, with an appendix examining the statistical properties of the Jackknife–manova method of matrix comparison
Authors: Bégin M. , Roff D. A. , Debat V.
Published: October 2004

We investigated the effect of temperature and wing morphology on the quantitative genetic variances and covariances of five size-related traits in the sand cricket, Gryllus firmus. Micropterous and macropterous crickets were reared in the laboratory at 24, 28 and 32 °C. Quantitative genetic parameters were estimated using a nested full-sib family design, and (co)variance matrices were compared using the T method, Flury hierarchy and Jackknife–manova method. The results revealed that the mean phenotypic value of each trait varied significantly among temperatures and wing morphs, but temperature reaction norms were not similar across all traits. Micropterous individuals were always smaller than macropterous individuals while expressing more phenotypic variation, a finding discussed in terms of canalization and life-history trade-offs. We observed little variation between the matrices of among-family (co)variation corresponding to each combination of temperature and wing morphology, with only one matrix of six differing in structure from the others. The implications of this result are discussed with respect to the prediction of evolutionary trajectories.
Complexity and integration in sexual ornamentation: an example with carotenoid and melanin plumage pigmentation
Authors: Badyaev A. V. , Young R. L.
Published: October 2004

Sexual ornaments often consist of several components produced by distinct developmental processes. The complexity of sexual ornaments might be favoured by mate choice of individual components in different environments which ultimately results in weak interrelationships (integration) among the developmental processes that produce these components. At the same time, sexual selection for greater exaggeration of individual components favours their stronger co-dependence on organismal resources. This should ultimately produce stronger condition-mediated integration among ornaments’ components in individuals with the most exaggerated ornamentation. Here we distinguish between these two sources of integration by examining the relationship between integration and elaboration of sexual ornamentation in three bird species: two with carotenoid-based sexual ornamentation (the house finch, Carpodacus mexicanus and common redpoll, Carduelis flammea) and a species with melanin-based sexual ornamentation (house sparrow, Passer domesticus). We found that integration of components varied with elaboration of carotenoid-based ornamentation but not of melanin ornamentation. In the house finches, integration was the highest in individuals with small ornaments and decreased with ornament elaboration whereas the pattern was the opposite in common redpolls. These results suggest that in these species integration and complexity of carotenoid-based ornamental components are due to shared condition-dependence of distinct developmental pathways, whereas integration and complexity of the melanin ornamentation is due to organismal integration of developmental pathways and is largely condition- and environment-invariant. Thus, functionally, ornamentation of the house sparrows can be considered a single trait, whereas complexity of the house finch and redpoll ornamentation varies with ornament elaboration and individual condition.
A phylogenomic approach to reconstructing the diversification of serine proteases in fungi
Authors: Hu G. , Leger R. J. St.
Published: October 2004

Using a phylogenomic approach with 10 fungi of very different virulence and habitat, we determined that there was substantial diversification of subtilase-type proteases early in ascomycete history (with subsequent loss in many lineages) but with no comparable diversification of trypsins. Patterns of intron loss and the degree of divergence between paralogues demonstrated that the proliferation of proteinase K subtilases and subtilisin type subtilases seen in pathogenic ascomycetes (Metarhizium anisopliae, Magnaporthe grisea, Fusarium graminearum) occurred after the basidiomycete/ascomycete split but predated radiation of ascomycete lineages. This suggests that the early ascomycetes had a lifestyle that selected for multiple proteases, whereas the current disparity in gene numbers between ascomycete lineages results from retention of genes in at least some pathogens that have been lost in other lineages (yeasts, Aspergillus nidulans, Neurospora crassa). A similar prevailing trend towards lineage specific gene loss of trypsins in saprophytes and some pathogens suggests that their phylogenetic breadth will have been much wider in early fungi than currently.
Predicting evolution of floral traits associated with mating system in a natural plant population
Authors: van Kleunen M. , Ritland K.
Published: October 2004

Evolution of floral traits requires that they are heritable, that they affect fitness, and that they are not constrained by genetic correlations. These prerequisites have only rarely been examined in natural populations. For Mimulus guttatus, we found by using the Riska-method that corolla width, anther length, ovary length and number of red dots on the corolla were heritable in a natural population. Seed production (maternal fitness) was directly positively affected by corolla width and anther size, and indirectly so by ovary length and number of red dots on the corolla. The siring success (paternal fitness), as estimated from allozyme data, was directly negatively affected by anther–stigma separation, and indirectly so by the corolla length–width ratio. Genetic correlations, estimated with the Lynch-method, were positive between floral size measures. We predict that larger flowers with larger reproductive organs, which generally favour outcrossing, will evolve in this natural population of M. guttatus.
Sexual isolation and extreme morphological divergence in the Cumaná guppy: a possible case of incipient speciation
Authors: Alexander H. J. , Breden F.
Published: October 2004

Theory predicts that sexual selection can promote the evolution of reproductive isolation and speciation. Those cases in which sexual selection has led to speciation should be characterized by significant differentiation in male display traits and correlated female preferences in the absence of post-zygotic isolation, accompanied by little genetic or other morphological differentiation. Previous evidence indicates that a cluster of populations of the guppy (Poecilia reticulata Peters) from Cumaná, Venezuela, the ‘Cumaná guppy’, differs significantly in female preferences from a nearby guppy population (A. Lindholm & F. Breden, Am. Nat., 160: 2002, S214). Here, we further document sexual isolation between these populations. In addition, these populations exhibit significant divergence in male display traits correlated to differences in between-population mating success, little mitochondrial genetic differentiation, and we find no evidence for genetic incompatibility between a Cumaná population and several geographically isolated populations. These results suggest that divergent sexual selection has contributed to differentiation of the Cumaná guppy, and this may be the first example of incipient speciation in the guppy.
Offspring-driven local dispersal in female sand lizards (Lacerta agilis)
Authors: Ryberg K. , Olsson M. , Wapstra E. , Madsen T. , Anderholm S. , Ujvari B.
Published: October 2004

We report on a field study in which determinants of female breeding dispersal (i.e. the shift in the mean home range coordinates between successive breeding events) was investigated. Offspring were released in full sib groups (or half sib ones if there was within-clutch multiple paternity) at a separation distance from the females that varied between ‘families’. This allowed for analysis of ‘offspring nearness’ effects on maternal dispersal. When a female's offspring were released more closely to her, she responded with greater dispersal. Furthermore, when the data set was truncated at 100 m maternal–offspring separation distance at offspring release (because perception at longer distances is likely to be unrealistic), maternal dispersal resulted in greater separation distance between female and offspring in the following year. A corresponding analysis for juveniles revealed no effect of maternal nearness on offspring dispersal but identified a significant effect of clutch size, to our surprise with dispersal declining with increasing clutch size. We discuss this result in a context of the ‘public information hypothesis’ (reinterpreted for juveniles in a nonsocial foraging species), suggesting that conspecific abundance perhaps acts as an indicator of local habitat quality. Thus, our analysis suggests a microgeographic structuring of the adult female population driven by genetic factors, either through inbreeding avoidance, or from simply avoiding individuals with a similar genotype regardless of their pedigree relatedness, while a nongenetic factor seems more important in their offspring.
The close relationship between estimated divergent selection and observed differentiation supports the selective origin of a marine snail hybrid zone
Authors: Cruz R. , Vilas C. , Mosquera J. , García C.
Published: October 2004

To study the role of divergent selection in the differentiation of the two morphs in a hybrid zone of the intertidal snail Littorina saxatilis, we compared the strength of the divergent selection acting on a series of shell characters (as estimated by the viability of snails in a reciprocal transplant experiment) with the contribution of these characters to the phenotypic differences between the morphs. We found a close correlation between selection and differentiation, which suggests a cause–effect relationship, i.e. that all present differentiation is the result of past divergent selection. In addition, divergent selection was a very important component of the total natural selection acting on shell measures. These novel results support previous evidence, based on allozyme analysis, of a parapatric origin for this hybrid zone. We discuss possible limitations of this interpretation and the circumstances under which allopatric differentiation would produce the same results. Phenotypic analysis of divergent selection may be a useful method of investigating the evolutionary mechanisms involved in differentiation processes.
General anesthesia in an infant with X‐linked myotubular myopathy
Authors: Costi David , van der Walt Johan H
Published: October 2004

We present a 20‐week‐old infant with the X‐linked form of myotubular myopathy who required anesthesia for a Nissen fundoplication procedure where the response to nondepolarizing neuromuscular blockade was evaluated.
Anesthesia for removal of inhaled foreign bodies in children
Authors: Soodan Amit , Pawar Dilip , Subramanium Rajeshwari
Published: October 2004

Background:  Foreign body aspiration may be a life‐threatening emergency in children requiring immediate bronchoscopy under general anesthesia. Both controlled and spontaneous ventilation techniques have been used during anesthesia for bronchoscopic foreign body removal. There is no prospective study in the literature comparing these two techniques. This prospective randomized clinical trial was undertaken to compare spontaneous and controlled ventilation during anesthesia for removal of inhaled foreign bodies in children.

Methods:  Thirty‐six children posted for rigid bronchoscopy for removal of airway foreign bodies over a period of 2 years and 2 months in our institution were studied. After induction with sleep dose of thiopentone or halothane, they were randomly allocated to one of the two groups. In group I, 17 children were ventilated after obtaining paralysis with suxamethonium. In group II, 19 children were breathing halothane spontaneously in 100% oxygen.

Results:  All the patients in the spontaneous ventilation group had to be converted to assisted ventilation because of either desaturation or inadequate depth of anesthesia. There was a significantly higher incidence of coughing and bucking in the spontaneous ventilation group compared with the controlled ventilation group (P = 0.0012).

Conclusion:  Use of controlled ventilation with muscle relaxants and inhalation anesthesia provides an even and adequate depth of anesthesia for rigid bronchoscopy.
Why cosmetic demand will never be satisfied
Authors: Smethurst D P
Published: October 2004

Waiting lists are Byzantine in nature and poorly understood. This commentary attempts to show how complexity itself is difficult to encapsulate and therefore why it is that attempts to reduce waiting lists are a little like trying to capture falling water. Starting with an apparently trivial problem borrowed from game theory I would like to traverse maths, economics and medicine in an attempt to generate a picture of waiting lists that transcends present‐day dogma and cuts to a more realistic, and at the same time intangible, representation of the core problem.
Temporary holiday “tattoos” may cause lifelong allergic contact dermatitis when henna is mixed with PPD
Authors: Onder M
Published: October 2004

Temporary tattoos are becoming more popular especially among teenagers. For this purpose henna tattoos are usually used. Although pure henna is relatively safe, combining it with other colouring agents such as para‐phenylenediamine (PPD), may cause skin sensitisation. Several cases of contact allergy from temporary tattoos have been reported, each with positive reactions to PPD.

Six cases of allergic contact reaction to temporary tattoos are reported. In all cases, the responsible agent was PPD. Two were also allergic to black ‘henna’ hair dye which also contained PPD. They had been sensitised on earlier holidays by their temporary tattoos.

Temporary holiday tattoos may cause lifelong contact allergy. Although the allergenicity of pure henna is low, the allergenicity of PPD is high. Holiday ‘tattoo’ reactions are going to be common until PPD is removed from the mixture.
Discolouration of the fingernails from using hydroquinone skin‐lightening cream
Authors: Parlak A Haydar , Aydoǧan İ , Kavak A
Published: October 2004

A 23‐year‐old left‐handed white male was referred with a complaint of brown discolouration of the fingernails of his left hand. He had been applying 4% hydroquinone cream to facial melasma. The discolouration began in winter and worsened in March and April. It resolved within 2 months of cessation of hydroquinone.

There are only a few reports of nail staining as a result of hydroquinone in the literature. Nail discolouration as a result of hydroquinone may occur on only one hand.
Atopic eczema. What has caused the epidemic in industrialised countries and can early intervention modify the natural history of atopic eczema?
Authors: Thestrup‐Pedersen K
Published: October 2004

Atopic eczema (AE) has a lifetime prevalence of between 15 and 20% in industrialized countries, but a very low prevalence in rural Africa. The ‘atopic eczema epidemic’ has developed in industrialized countries within the last four decades. The disease has a strong genetic influence, so environmental factors must be responsible for the dramatic increase in disease prevalence. It is therefore fair to consider what interventions may change its prevalence. In this article, several factors are considered: the increased number of doctors in industrialized countries, the development of drugs like topical steroids and emollients, the ‘demanding parents’ and ‘old mother’ syndromes, introduction of vaccination programmes, allergen exposure, breastfeeding and the possible beneficial effects of probiotics.

In 90% of children with AE, onset is before the age of 5. Its course runs over years. Approximately two out of three outgrow the disease between 7 and 12 years of age. Although its cause is unknown, type I allergic reactions are common and allergen avoidance has been attempted in many studies as a preventive measure in atopic dermatitis. However, results are rather disappointing.

The use of probiotics, i.e. daily intake of Lactobacillus, has proven effective in preventing, or at least delaying, the development of atopic eczema. So has breastfeeding, although some studies cannot confirm its beneficial effect. Therapeutic interventions using antihistamines, desensitisation and control of skin inflammation using topical steroids have not proven successful in shortening the course of atopic eczema, although controlled studies are lacking. The use of emollients has, however, a documented effect in up to one of three children with mild atopic eczema. It will be interesting to observe if the new topical immuno‐modulators, tacrolimus and pimecrolimus, may be able to shorten the natural course of the disease.
Ready, SET, Go!
Authors: Korsunsky Boris
Published: October 2004

If there is one thing that physics educators are likely to agree on, it is the notion that learning problem-solving skills is one of the primary goals of physics education. In this article, I propose a set of problem-solving approaches—and separately, a set of related teaching strategies—based on the research project that I have recently completed.1
Classroom Demonstration of Magnetic Force
Authors: Kraftmakher Yaakov
Published: October 2004

Some classroom demonstrations are possible with the use of a data-acquisition system. One such demonstration is described below. The magnetic force acting on a current-carrying conductor is measured as a function of the flowing current. The demonstration consists of weighing a straight current-carrying conductor subjected to a uniform magnetic field of a permanent magnet. The magnetic force acting on the conductor shows the influence of the magnetic field on moving electric charges. For the demonstration, one needs a force sensor and a sensor measuring the current flowing through the conductor. Both sensors are connected to a data-acquisition system. The demonstration gives better understanding of the magnetic force acting on a current-carrying conductor, as well as on moving electric charges.
Naturally derived commercial surfactants differ in composition of surfactant lipids and in surface viscosity
Authors: Rüdiger Mario , Tölle Angelika , Meier Wolfgang , Rüstow Bernd
Published: October 2004

Pulmonary surfactant biophysical properties are best described by surface tension and surface viscosity. Besides lecithin, surfactant contains a variety of minor lipids, such as plasmalogens, polyunsaturated fatty acid-containing phospholipids (PUFA-PL), and cholesterol. Plasmalogens and cholesterol improve surface properties of lipid mixtures significantly. High PUFA-PL and plasmalogen content in tracheal aspirate of preterm infants reduces the risk of developing chronic lung disease. Different preparations are available for exogenous surfactant substitution; however, little is known about lipid composition and surface viscosity. Thus lipid composition and surface properties (measured by oscillating drop surfactometer) of three commercial surfactant preparations (Alveofact, Curosurf, Survanta) were compared. Lipid composition exhibited strong differences: Survanta had the highest proportion of disaturated PL and total neutral lipids and the lowest proportion of PUFA-PL. Highest plasmalogen and PUFA-PL concentrations were found in Curosurf (3.8 ± 0.1 vs. 26 ± 1 mol%) compared with Alveofact (0.9 ± 0.3 vs. 11 ± 1) and Survanta (1.5 ± 0.2 vs. 6 ± 1). In Survanta samples, viscosity increased >8 × 10−6kg/s at surface tension of 30 mN/m. Curosurf showed only slightly increased surface viscosity below surface tensions of 25 mN/m, and viscosity did not reach 5 × 10−6kg/s. By adding defined PL to Survanta, we obtained a Curosurf-like lipid mixture (without plasmalogens) that exhibited biophysical properties like Curosurf. Different lipid compositions could explain some of the differences in surface viscosity. Therefore, PL pattern and minor surfactant lipids are important for biophysical activity and should be considered when designing synthetic surfactant preparations.
Language Experience and the Organization of Brain Activity to Phonetically Similar Words: ERP Evidence from 14- and 20-Month-Olds
Authors: Mills Debra L. , Prat Chantel , Zangl Renate , Stager Christine L. , Neville Helen J. , Werker Janet F.
Published: October 2004

The ability to discriminate phonetically similar speech sounds is evident quite early in development. However, inexperienced word learners do not always use this information in processing word meanings [Stager & Werker (1997). Nature, 388, 381–382]. The present study used event-related potentials (ERPs) to examine developmental changes from 14 to 20 months in brain activity important in processing phonetic detail in the context of meaningful words. ERPs were compared to three types of words: words whose meanings were known by the child (e.g., “bear”), nonsense words that differed by an initial phoneme (e.g., “gare”), and nonsense words that differed from the known words by more than one phoneme (e.g., “kobe”). These results supported the behavioral findings suggesting that inexperienced word learners do not use information about phonetic detail when processing word meanings. For the 14-month-olds, ERPs to known words (e.g., “bear”) differed from ERPs to phonetically dissimilar nonsense words (e.g., “kobe”), but did not differ from ERPs to phonetically similar nonsense words (e.g., “gare”), suggesting that known words and similar mispronunciations were processed as the same word. In contrast, for experienced word learners (i.e., 20-month-olds), ERPs to known words (e.g., “bear”) differed from those to both types of nonsense words (“gare” and “kobe”). Changes in the lateral distribution of ERP differences to known and unknown (nonce) words between 14 and 20 months replicated previous findings. The findings suggested that vocabulary development is an important factor in the organization of neural systems linked to processing phonetic detail within the context of word comprehension.
A Comparison of the Electroencephalogram between Institutionalized and Community Children in Romania
Authors: Marshall Peter J. , Fox Nathan A. , Group BEIP Core
Published: October 2004

Electroencephalographic (EEG) data were collected from a sample of institutionalized infants and young children in Bucharest, Romania, and were compared with EEG data from age-matched children from the local community who had never been institutionalized and who were living with their families in the Bucharest area. Compared with the never-institutionalized group, the institutionalized group showed a pattern of increased low-frequency (theta) power in posterior scalp regions and decreased high-frequency (alpha and beta) power, particularly at frontal and temporal electrode sites. This finding is consistent with EEG studies of children facing environmental adversity and children with learning disorders. The institutionalized group also showed less marked hemispheric EEG asymmetries than the never-institutionalized group, particularly in the temporal region. The results are discussed in the context of two models: that the pattern of EEG in the institutionalized children reflects a maturational lag in nervous system development, or that it reflects tonic cortical hypoactivation.
The Faces of Development: A Review of Early Face Processing over Childhood
Authors: Taylor M. J. , Batty M. , Itier R. J.
Published: October 2004

The understanding of the adult proficiency in recognizing and extracting information from faces is still limited despite the number of studies over the last decade. Our knowledge on the development of these capacities is even more restricted, as only a handful of such studies exist. Here we present a combined reanalysis of four ERP studies in children from 4 to 15 years of age and adults (n = 424, across the studies), which investigated face processing in implicit and explicit tasks. We restricted these analyses to what was common across studies: early ERP components and upright face processing across all four studies and the inversion effect, investigated in three of the studies. These data demonstrated that processing faces implicates very rapid neural activity, even in young children— at the P1 component—with protracted age-related change in both P1 and N170, that were sensitive to the different task demands. Inversion produced latency and amplitude effects on the P1 from the youngest group, but on N170 only starting in mid childhood. These developmental data suggest that there are functionally different sources of the P1 and N170, related to the processing of different aspects of faces.
Asynchronies in the Development of Electrophysiological Responses to Motion and Color
Authors: Mitchell Teresa V. , Neville Helen J.
Published: October 2004

Recent reports have documented greater plasticity in the dorsal visual stream as compared with the ventral visual stream. This study sought to test the hypothesis that this greater plasticity may be related to a more protracted period of development in the dorsal as compared with the ventral stream. Age-related effects on event-related potentials (ERPs) elicited by motion and color stimuli, designed to activate the two visual streams, were assessed in healthy individuals aged 6 years through adulthood. Although significant developmental effects were observed in amplitudes of ERPs to both color and motion stimuli, marked latency effects were observed only in response to motion. These results provide support for the hypothesis that the dorsal stream displays a longer developmental time course across the early school years than the ventral stream. Implications for neural and behavioral plasticity are discussed.
An Interacting Systems Model of Infant Habituation
Authors: Sirois Sylvain , Mareschal Denis
Published: October 2004

Habituation and related procedures are the primary behavioral tools used to assess perceptual and cognitive competence in early infancy. This article introduces a neurally constrained computational model of infant habituation. The model combines the two leading process theories of infant habituation into a single functional system that is grounded in functional brain circuitry. The HAB model (for Habituation, Autoassociation, and Brain) proposes that habituation behaviors emerge from the opponent, complementary processes of hippocampal selective inhibition and cortical long-term potentiation. Simulations of a seminal experiment by Fantz [Visual experience in infants: Decreased attention familiar patterns relative to novel ones. Science, 146, 668–670, 1964] are reported. The ability of the model to capture the fine detail of infant data (especially age-related changes in performance) underlines the useful contribution of neurocomputational models to our understanding of behavior in general, and of early cognition in particular.
Mechanisms of Eye Gaze Perception during Infancy
Authors: Farroni Teresa , Johnson Mark H. , Csibra Gergely
Published: October 2004

Previous work has shown that infants are sensitive to the direction of gaze of another's face, and that gaze direction can cue attention. The present study replicates and extends results on the ERP correlates of gaze processing in 4-month-olds. In two experiments, we recorded ERPs while 4-month-olds viewed direct and averted gaze within the context of averted and inverted heads. Our results support the previous finding that cortical processing of faces in infants is enhanced when accompanied by direct gaze. However, this effect is only found when eyes are presented within the context of an upright face.
Knowing Where Things Are in the Second Year of Life: Implications for Hippocampal Development
Authors: Sluzenski Julia , Newcombe Nora S. , Satlow Eric
Published: October 2004

Prior data have revealed striking contrasts between 18 and 24-month-old children in place learning, an ability knownto dependon the hippo campus(Newcombe, Huttenlocher, Drummey, & Wiley, 1998). The current research examined the development of three other basic abilities of mature spatial competence: the representation of multiple locations, the learning of relations among objects, and the recall of a single location after a substantial filled delay. Results indicated a transition from 18 to 24 months in all three abilities. This evidence supports a general transition in spatial representation that occurs towards the end of infancy. Existing neurobehavioral data suggest that a corresponding change in hippocampal functioning underlies this development.
Polychlorinated biphenyls, cytochrome P450 1A1 (CYP1A1) polymorphisms, and breast cancer risk among African American women and white women in North Carolina: a population-based case-control study
Authors: Li Yu , Millikan Robert C , Bell Douglas A , Cui Lisa , Tse Chiu-Kit J , Newman Beth , Conway Kathleen
Published: October 2004

Introduction

Epidemiologic studies have not shown a strong relationship between blood levels of polychlorinated biphenyls (PCBs) and breast cancer risk. However, two recent studies showed a stronger association among postmenopausal white women with the inducible M2 polymorphism in the cytochrome P450 1A1 (CYP1A1) gene.

Methods

In a population-based case-control study, we evaluated breast cancer risk in relation to PCBs and the CYP1A1 polymorphisms M1 (also known as CYP1A1*2A), M2 (CYP1A1*2C), M3 (CYP1A1*3), and M4 (CYP1A1*4). The study population consisted of 612 patients (242 African American, 370 white) and 599 controls (242 African American, 357 white).

Results

There was no evidence of strong joint effects between CYP1A1 M1-containing genotypes and total PCBs in African American or white women. Statistically significant multiplicative interactions were observed between CYP1A1 M2-containing genotypes and elevated plasma total PCBs among white women (P value for likelihood ratio test = 0.02). Multiplicative interactions were also observed between CYP1A1 M3-containing genotypes and elevated total PCBs among African American women (P value for likelihood ratio test = 0.10).

Conclusions

Our results confirm previous reports that CYP1A1 M2-containing genotypes modify the association between PCB exposure and risk of breast cancer. We present additional evidence suggesting that CYP1A1 M3-containing genotypes modify the effects of PCB exposure among African American women. Additional studies are warranted, and meta-analyses combining results across studies will be needed to generate more precise estimates of the joint effects of PCBs and CYP1A1 genotypes.
The effect of interruption to propofol sedation on auditory event-related potentials and electroencephalogram in intensive care patients
Authors: Yppärilä Heidi , Nunes Silvia , Korhonen Ilkka , Partanen Juhani , Ruokonen Esko
Published: October 2004

Introduction

In this observational pilot study we evaluated the electroencephalogram (EEG) and auditory event-related potentials (ERPs) before and after discontinuation of propofol sedation in neurologically intact intensive care patients.

Methods

Nineteen intensive care unit patients received a propofol infusion in accordance with a sedation protocol. The EEG signal and the ERPs were measured at the frontal region (Fz) and central region (Cz), both during propofol sedation and after cessation of infusion when the sedative effects had subsided. The EEG signal was subjected to power spectral estimation, and the total root mean squared power and spectral edge frequency 95% were computed. For ERPs, we used an oddball paradigm to obtain the N100 and the mismatch negativity components.

Results

Despite considerable individual variability, the root mean squared power at Cz and Fz (P = 0.004 and P = 0.005, respectively) and the amplitude of the N100 component in response to the standard stimulus at Fz (P = 0.022) increased significantly after interruption to sedation. The amplitude of the N100 component (at Cz and Fz) was the only parameter that differed between sedation levels during propofol sedation (deep versus moderate versus light sedation: P = 0.016 and P = 0.008 for Cz and Fz, respectively). None of the computed parameters correlated with duration of propofol infusion.

Conclusion

Our findings suggest that use of ERPs, especially the N100 potential, may help to differentiate between levels of sedation. Thus, they may represent a useful complement to clinical sedation scales in the monitoring of sedation status over time in a heterogeneous group of neurologically intact intensive care patients.
Use of simulation in the design of a large, naturally ventilated office building
Authors: Haves P , Linden PF , Da Graça G Carrilho
Published: October 2004

The design for the new Federal Building for San Francisco includes an office tower that is to be naturally ventilated. The EnergyPlus thermal simulation program was used to evaluate different ventilation strategies for space cooling and rationalize the design of the façade. The strategies include ventilation driven by different combinations of wind, internal stack and external stack. The simulation results indicate that wind-driven ventilation can maintain adequate comfort even during hot periods. Computational fluid dynamics was used to study the airflow and temperature distribution in the occupied spaces arising from different combinations of window openings and outside conditions and thereby inform both the design of the windows and the control strategy.
Exergy analysis of a low temperature radiant heating system
Authors: Asada Hideo , Boelman EC
Published: October 2004

The purpose of this study is to gain insight into the process of heating a room with a low-temperature radiant heating system and solar energy, considering energy conversion and heat transfer steps in the building (where heat is required), in the incident solar radiation (which supplies part of the heat required) and in the heating system (which provides for the additional heating needs, by using electricity from a gas-fired power plant to drive a heat pump). We applied a theoretical framework developed by Shukuya et al., to a dynamic simulation model and did numerical calculations for a room with an exterior wall, with and without a south-facing window, during a heating season in the Netherlands. The exergy analysis allows direct comparison between different energy types (e.g., heat, electricity, fuel) on a common basis, and the concept of exergy consumption is useful for expressing how and where energy is dispersed in the course of energy conversion and heat transfer steps. The results show that exergy consumption in the room (demand side) is relatively small compared to the supply side (fuel burned at the power plant and the sun reaching the ground and facade). The calculations also show that the total amount of exergy consumed during the heating season can be larger than the total amount of exergy supplied during the same period, as a result of heat storage in the building mass, and of changes in the outdoor temperature between the moment of heat storage and heat release.
Energy balance study of water ponds and its influence on building energy consumption
Authors: Inard C , Groleau D , Musy M
Published: October 2004

This study investigates the energy exchanges occurring in the volume and on the surface of water ponds and their influence on the energy consumption of a building. The mathematical model of water ponds is based on coupling the thermal model of the water pond and the airflow model of the surrounding air. It accounts for the heat transfer by radiation, conduction, convection and the latent heat transfer due to water evaporation. The governing equations are numerically solved by a finite difference method for the thermal model and by a finite volume method for the air flow model. The surface temperature and the spatial profiles of temperature and moisture are presented. The effect of the water pond on the cooling energy consumption is discussed.
Design and testing of a control strategy for a large, naturally ventilated office building
Authors: da Graça G Carrilho , Linden PF , Haves P
Published: October 2004

The design for the new Federal Building for San Francisco includes an office tower that is to be naturally ventilated. Each floor is designed to be cross-ventilated, through upper windows that are controlled by the building management system. Users have control over lower level windows, which can be as much as 50% of the total openable area. There are significant differences in the performance and the control of the windward and leeward sides of the building, and separate monitoring and control strategies are determined for each side. The performance and control of the building has been designed and tested using a modified version of EnergyPlus. Results from studies with EnergyPlus and computational fluid dynamics are used in designing the control strategy. Wind-driven cross-ventilation produces a main jet through the upper openings of the building, across the ceiling from the windward to the leeward side. Below this jet, the occupied regions are subject to a recirculating airflow. Results show that temperatures within the building are predicted to be satisfactory, provided a suitable control strategy is implemented that uses night cooling in periods of hot weather. The control strategy has 10 window opening modes. EnergyPlus was extended to simulate the effects of these modes, and to assess the effects of different forms of user behaviour. The results show how user behaviour can significantly influence the building performance.
Selecting an appropriate tool for airflow simulation in buildings
Authors: Djunaedy E , Hensen JLM , Loomans MGLC
Published: October 2004

With the advancement of technology, and with the widespread availability of simulation tools, we are forced to consider which simulation tool would be appropriate for a particular problem. This seemingly trivial decision is in reality not very easy to make. Very often this leads to the practice of using the most sophisticated tool available for every problem. The levels of resolution and complexity of simulations are directly related to the accuracy of the simulation and to the total cost of the simulation process. A simple tool may be cheaper, but there is a high risk of inaccuracy. An advanced tool could be more accurate, but it needs a huge amount of resource in terms of computing power, labour, and the advanced knowledge to perform the simulation and interpret the results. This paper proposes a guideline for selecting a simulation tool for airflow prediction. Sensitivity analysis is selected as the tool for decision making. A case study is used to highlight the proposed method.