Two-year-olds will name artifacts by their functions.

Do young children take functional information into account in naming artifacts? In three studies of lexical categorization, 112 children 2 years of age learned new names for novel artifacts with novel functions and then extended the names to new objects. The objects were designed to have functions that were causally related in simple and compelling ways to perceptible aspects of their physical structure. Despite only minimal opportunity to familiarize themselves with the objects, children generalized the names in accordance with the objects' functions. This result obtained even when children had to discover the functions of the named objects on their own (Experiment 2) and when all the test objects had some discernible function (Experiment 3). Two-year-olds name by function when they can make sense of the relation between the appearances and the functions of artifacts.

Young children's use of functional information to categorize artifacts: three factors that matter.

Three experiments addressed factors that might influence whether or not young children take into account function, as opposed to overall appearance or shape, when they extend the names of novel artifacts. Experiment 1 showed that 4-year-olds more often extend a name on the basis of a demonstrated function when that function provides a plausible causal account of perceptible object structure. Experiment 2 showed that they more often extend a name by function when they respond slowly, and hence thoughtfully. Experiment 3 demonstrated that they are more likely to take function into account when they extend names than when they judge similarities. Comparisons of lexical and non-lexical conditions in younger children failed to show any differences. Overall, the findings suggest that by 4 years of age, children may learn names as labels for novel artifact kinds rather than perceptual classes, and that the processes by which they categorize may be mindful and reflective, as in adults.

Wood's lamp utility in the identification of semen.

BACKGROUND: The accurate detection of semen is critical to forensic, medical, and legal personnel. The Wood's lamp (WL) emits ultraviolet light (UVL) and has been identified as useful in rape evaluations because it is purported to cause semen to fluoresce. This study was intended to determine if semen can be distinguished from other products by WL analysis. METHODS: Investigators reviewed the previous training and frequency of use of the WL by emergency medicine and pediatric emergency medicine physicians at 2 medical centers. The participants were asked to use a WL to distinguish between a semen sample (<6 hours old) and 13 commonly used products. Next, 29 semen samples were collected and evaluated under high-power microscopy and under UVL. RESULTS: A total of 41 physicians participated in the study (68% male). The number of years practicing in an emergency setting spanned from.3 to 25 years with a mean of 7. 1 years. A total of 51% of participants trained in emergency medicine, 23% in pediatrics and pediatric emergency medicine. A total of 22% reported formal training in the collection of forensic evidence. A total of 62% of the physicians believed they have identified semen in the past; one third felt they could differentiate semen from other products under UVL. None of the 41 physicians were able to differentiate semen from other products using a WL. Moreover, the semen samples used for the study did not fluoresce under WL analysis. None of the 29 semen samples fluoresced whether wet or dry. The medicaments most commonly mistaken for semen were A&D ointment (Cardinal Health, Inc, Dublin, OH), Surgilube (Division of Atlanta, Inc, Melville, NY), Barrier cream (Carrington Laboratories, Inc, Irving, TX), and bacitracin (Division of Atlanta, Inc, Melville, NY). CONCLUSIONS: Participating physicians were unable to distinguish between semen and other common products, using the WL. Although the WL has been purported to be a useful tool as a screening device for the detection of seminal stains, the investigators have found it to be unreliable. Semen, previously reported to fluoresce under WL analysis, does not appear to do so. The correct identification of semen may be complicated by the presence of previously existing ointments and creams, some of which may be iatrogenically introduced (ie, Surgilube).

Intravenous catheter blood cultures: utility and contamination.

OBJECTIVE: In pediatrics, blood cultures (BCs) are often drawn as intravenous (IV) catheters are placed. This routine minimizes the number of painful and often difficult punctures a child must undergo but results in the discarding of multiple BC bottles when these cultures are later determined to be unnecessary. If the contamination rate of BCs drawn through an indwelling IV did not exceed the contamination rate of BCs drawn at the time of IV placement, BCs could be drawn from the IV without subjecting the patient to another venipuncture. This study was done to compare the contamination rates of BCs drawn by these two methods. Additionally, we sought to determine if the collection of two BCs enhances pathogen recovery. METHODS: Prospective comparison of contamination and bacteremia rates of BCs drawn by two different methods: the first BC was drawn at the time of IV line placement and the second BC was drawn from the previously placed IV at a later time. Setting. Urban pediatric emergency department with an annual census of 40 000. PARTICIPANTS: One thousand five hundred sixty-four patients between the ages of 3 days and 22.1 years. The median age was 2.2 years. Sixty-four patients were excluded because we were unable to draw the second BC. Forty-six percent of eligible patients (n = 690) were girls. RESULTS: Fifty-seven (1.9%) of 3000 grew contaminants: 27 in the first and 30 in the second BC for contamination rates of 1.8% and 2.0%. Thirty-eight (1.3%) of 3000 BCs grew pathogens: 24 represent 12 patients with growth in two out of two cultures and 14 represent 14 patients with growth in one out of two cultures. Pathogen rates were 1.1% (16/1500) with one BC per patient and 1.7% (22/1500) with two BCs per patient. CONCLUSIONS: There is no difference in the contamination rates of two BCs drawn from the same site at two different times. The collection of two BCs per patient may enhance pathogen recovery.

Evaluation of febrile children with petechial rashes: is there consensus among pediatricians?

BACKGROUND: The evaluation of febrile children with petechial rashes evokes controversy. Although many of these children have viral infections, on occasion such patients may be infected with Neisseria meningitidis. OBJECTIVE: To investigate differences in practice trends for the evaluation and management of non-toxic-appearing febrile children with petechial rashes among pediatric specialty groups. METHODS: We surveyed 833 pediatricians in 4 specialties [community (CGP) and academic (AGP) general pediatrics, emergency medicine (EM) and infectious diseases] regarding 4 hypothetical non-toxic-appearing febrile children ages 1, 2, 5 and 7 years. The patients differed with regard to clinical appearance, distribution of petechiae and complete blood count results. We compared specialty group responses, adjusting for practice setting, population size and years in practice using multiple logistic regression analysis. RESULTS: The survey was completed and returned by 416 (50%) pediatricians. There was substantial variation in the evaluation of the 2 younger febrile children without clear sources for their petechiae. For the 1-year-old the overall blood culture (BCx) rate was 82%, with the EM group (91%) more often requesting BCx than either the CGP (76%) or AGP (73%, P=0.001) groups. The overall hospital admission rate was 31%, with CGP less often requesting admission than infectious disease pediatricians (22% vs. 40%, P=0.007). In the regression analysis the only significant difference between groups was in BCx rate between the EM and AGP groups. For the 2-year-old the overall rate of BCx was 95%, lumbar puncture was 41% and admission was 44%, with no significant differences among groups. For the scenarios involving the 2 older febrile children with sources for their petechiae, the majority of respondents chose neither lumbar puncture nor admission. There was disagreement regarding BCx, both within and between groups, although most of the between group differences did not persist in the regression analysis. CONCLUSIONS: There are substantial differences among pediatricians in the evaluation of young non-toxic-appearing febrile children with petechial rashes. Although there are some differences between pediatric subspecialties, most of these differences do not persist after adjusting for practice setting, population size and physician experience.

Lymphoma of the extrahepatic biliary ducts in acquired immunodeficiency syndrome.

Gastrointestinal neoplasia in acquired immunodeficiency syndrome (AIDS) frequently presents as a non-Hodgkin's lymphoma or Kaposi's sarcoma, at sites including the oral cavity, esophagus, small bowel, and mesenteries. Primary lymphoma of the biliary ducts, even in the setting of AIDS, is rare. This patient, an older male with no preoperatively known AIDS risk factors, presented with painless jaundice and radiographic findings of focal hepatic duct stenosis, suggesting either a Klatskin tumor or sclerosing cholangitis. Only after the pathologic diagnosis of a malignant large cell lymphoma from the en bloc tumor specimen was his human immunodeficiency virus status ascertained and noted to be positive.

Thoracoscopic assisted pneumonectomy.

A lung carcinoma with tumor involving more than one lobe or in close proximity to the mainstem bronchus often requires pneumonectomy for surgical cure. Inflammation, bulky tumors, and dense adhesions limit the operative field of vision and may result in the abandonment of procedures with potential for complete extirpation. This case illustrates the utility of thoracoscopy in visualization of the hilum and other neurovascular structures in a patient with a proximal tumor and dense intrathoracic adhesions. Successful resection was made possible by use of combined open and thoracoscopic modalities.

Effects of triclosan and triclosan monophosphate on maximum specific growth rates, biomass and hydrolytic enzyme production of Streptococcus sanguis and Capnocytophaga gingivalis in continuous culture.

Dental plaque species, Streptococcus sanguis and Capnocytophaga gingivalis, were grown in continuous culture with progressively increasing concentrations of triclosan or its phosphorylated derivative, triclosan monophosphate (TMP). For both organisms, the maximum specific growth rates decreased with increasing concentrations of triclosan or TMP until complete inhibition of growth occurred, which for S. sanguis was at 20 mg/L and 50 mg/L, and for C. gingivalis was at 10 mg/L and 5 mg/L for triclosan and TMP respectively. For both species, biomass levels remained approximately constant or, in some cases, increased slightly at low levels of triclosan or TMP. However, biomass levels then decreased significantly as the triclosan or TMP concentrations approached lethal levels. For S. sanguis, levels of hydrolytic enzymes (acid phosphatase, leucine aminopeptidase and esterase) generally remained approximately constant or increased with increasing concentrations of triclosan or TMP until close to inhibitory levels where enzyme levels were reduced. The ratio of extracellular soluble enzymes to cell-bound enzymes remained constant or increased slightly with increasing levels of triclosan or TMP. For C. gingivalis, production of hydrolytic enzymes (neutral phosphatase, leucine aminopeptidase and trypsin-like protease) remained constant or were reduced when grown with low levels of triclosan and TMP but in some cases increased with higher levels of agents. The proportion of extracellular soluble activity increased significantly when concentrations of agent neared inhibitory levels. The results taken together show that the physiology of cells is significantly altered and that hydrolytic enzymes are released from the cells when these are grown in the presence of increasing concentrations of triclosan or TMP. Enzyme release is more pronounced in the Gram-negative C. gingivalis and indicates that triclosan or TMP can cause membrane perturbation with subsequent release of membrane-located (S. sanguis) or periplasmic (C. gingivalis) hydrolytic enzymes. S. sanguis was more sensitive to triclosan than TMP while C. gingivalis was more sensitive to TMP. This suggests that, in C. gingivalis, TMP may diffuse into the cell wall more easily than triclosan and then be converted to triclosan by phosphatase activity within the cell wall complex, where it may give rise to high localized concentrations and subsequent cell damage.

Fluoride analysis of apatite crystals with a central planar OCP inclusion: concerning the role of F- ions on apatite/OCP/apatite structure formation.

To study the roles of F- ions in the formation of apatite crystals embedding octacalcium phosphate (OCP) lamella in the center of apatite (Ap), a range of the Ap/OCP/Ap lamellar-mixed crystals were synthesized under various concentrations of fluoride ion (F-) from 0. 1-1.0 ppm at pH 6.5 and 37 degrees C. The products were analyzed for the F- incorporation, F- distribution, and the amount of OCP and Ap by chemical analysis, X-ray diffraction (XRD), electron probe microanalysis (EPMA), and nuclear magnetic resonance (NMR) techniques. The F- content and the amount of apatite in the crystalline product increased with an increase in the F- concentration in solution, whereas the amount of OCP and the yield of total product decreased. EPMA indicated that F- ions are distributed in the crystals almost homogeneously. The combined analysis suggested that a low-substituted fluoridated hydroxyapatite (FHAp) grew on a small amount of F--containing OCP or on a surface-reaction layer of OCP, which has accumulated a small amount of F-. The roles of F- ions were hypothesized as the reduction of the growth rate and/or the critical thickness in the a*-axis direction of OCP, the enhancement of hydrolysis of OCP, and the activation of the growth of FHAp, resulting in thinner OCP lamella and thicker apatite lamella in the a*-axis direction with an increase in F- concentration.

Hydrolysis of triclosan monophosphate by dental plaque and selected species of oral micro-organisms.

Triclosan monophosphate is a phosphorylated derivative of the antimicrobial agent, triclosan. In comparison with triclosan, it is highly soluble in aqueous solutions. It is hypothesized that, within the oral environment, triclosan monophosphate (which may be devoid of antimicrobial activity) will be hydrolyzed into triclosan by the action of microbial phosphatases. The liberated triclosan may then exert antimicrobial activity. To test this hypothesis, we designed experiments to measure the phosphatase activity of plaque and selected species of oral micro-organisms and to demonstrate hydrolysis of triclosan monophosphate. Tests comparing the minimal inhibitory concentration and minimal bactericidal concentration of triclosan and triclosan monophosphate were also undertaken. Dental plaque and the majority of the bacterial strains tested showed phosphatase activity against p-nitrophenyl phosphate which peaked below neutral pH (acid phosphatases) or above neutral pH (alkaline phosphatases). Dental plaque showed the highest levels of alkaline phosphatase (optimum at pH 9.0) and relatively high levels of acid phosphatase (optimum at pH 6.0 to 6.5). Dental plaque and selected species of micro-organisms were all capable of hydrolyzing triclosan monophosphate, albeit at different rates. The minimal inhibitory concentration and minimal bactericidal concentration values for triclosan monophosphate against eight bacterial strains were always considerably higher than the corresponding values for triclosan. Addition of triclosan monophosphate to an established culture (ca. 10(9) cfu/mL) of Capnocytophaga gingivalis growing continuously showed that triclosan monophosphate was rapidly hydrolyzed into triclosan with concomitant loss of total bacterial viability. It is therefore likely that triclosan monophosphate will be broken down into triclosan within the oral environment with concomitant antimicrobial activity.

Infants' sensitivity to word boundaries in fluent speech.

Infants' sensitivity to word units in fluent speech was examined by inserting I sec pauses either at boundaries between successive words (Coincident versions) or between syllables within words (Noncoincident versions). In Experiment 1, 24 11-month-olds listened significantly longer to the Coincident versions. In Experiment 2, 24 four-and-a-half- and 24 nine-month-olds did not exhibit the preference for the Coincident versions that the 11-month-olds showed. When the stimuli were low-pass filtered in Experiment 3, 24 11-month-olds showed no preference for the Coincident versions, suggesting they rely on more than prosodic cues. New stimulus materials in Experiment 4 indicated that responses by 24 11-month-olds to the Coincident and Noncoindent versions did not depend solely on prior familiarity with the targets. Two groups of 30 11-month-olds tested in Experiment 5 were as sensitive to groups of 30 11-month-olds tested in Experiment 5 were as sensitive to boundaries for Strong/Weak words as for Weak/Strong words. Taken together, the results suggest that, by 11 months, infants are sensitive to word boundaries in fluent speech, and that this sensitivity depends on more than just prosodic information or prior knowledge of the words.

Does sentential prosody help infants organize and remember speech information?

Theories that propose a mapping between prosodic and syntactic structures require that prosodic units in fluent speech be perceptually salient for infants. Although previous studies have demonstrated that infants are sensitive to prosodic markers of syntactic units, they do not show that prosodic information really has an impact on how infants encode the speech they hear. Two experiments were conducted to examine whether infants as young as 2 months old might actually use the prosody afforded by sentences to organize and remember spoken information. The results suggest that infants better remember the phonetic properties of (1) words that are prosodically linked together within a single clause as opposed to individual items in a list (Experiment 1); and (2) words that are prosodically linked within a single clausal unit as opposed to spanning two contiguous fragments (Experiment 2). Taken together, the evidence from both experiments suggests that the prosodic organization of speech into clausal units enhances infants' memory for spoken information. These findings are discussed with regard to their implications for theories of language acquisition.

Mode of action of fluoride: application of new techniques and test methods to the examination of the mechanism of action of topical fluoride.

Modern techniques in dental research continue to assist in the study of the mode of (anticaries) action of topical fluorides. The Plaque Glycolysis and Regrowth Model (PGRM) facilitates the standardized assessments of antimicrobial effects on plaque following use of test formulations in vivo without complications arising from coincident mineral reactivity. In vivo plaque glycolysis testing demonstrates that topically applied fluoride, at conventional levels found in dentifrices, has only modest effects on the metabolic (acid-producing) activity of dental plaque. Any 'plaque' contribution to fluoride efficacy must come from more subtle effects on plaque acidogenicity than those measured in PGRM. The 19-FMAS NMR (Magic Angle Spinning Nuclear Magnetic Resonance) technique provides unambiguous measures of the reaction products of F-enamel interactions. Studies have revealed a new 'reaction product' of fluoride-enamel interactions--designated as Non-Specifically-Adsorbed Fluoride, NSAF. This species, along with FAP (fluoroapatite), FHAP (fluorohydroxyapatite), and CaF2 (calcium fluoride), contributes to the remineralization/demineralization benefits of fluoride. pH cycling and in situ denture chip studies permit quantitative assessments to be made of the relative benefits of fluoride in promoting remineralization and in inhibiting demineralization. Results from pH cycling/in situ experiments are strongly supportive of Koulourides' 'Acquired Acid Resistance' concept, describing fluoride's decay-preventive effects. The continued application of new analytical/physical techniques and testing regimens to the study of fluoride anticaries mechanisms may lead to the development of improved fluoride agents/treatment modalities for the prevention of dental caries.

What child is this? What interval was that? Familiar tunes and music perception in novice listeners.

In the laboratory, musical novices often seem insensitive even to basic structural elements of music (octaves, intervals, etc.), undermining long-held theories of music perception, and threatening to leave current theories applicable only to experts. Consequently it is important to demonstrate novices' basic listening competence where possible. Two experiments examined the perception of musical intervals (minor thirds, major thirds and perfect fourths) by musical novices. Subjects received either standard instructions or familiar folk-tune labels to aid performance. The folk-tune labels greatly improved identification performance, producing expert-caliber performance by some musically inexperienced subjects. The effectiveness of the folk-tune manipulation was much more limited in a difficult discrimination task. The results suggest that novices do have some basic competence when assayed appropriately, and that familiar musical tokens may be a critical element in such assays. Larger implications of the role of familiarity in novices' competence are discussed, including those that relate to music cognition and aesthetics.

Processing integral dimensions: the whole view.

In the traditional view, integral dimensions are said to be processed as unitary whole and only occasionally analyzed. Converging operations establish that (a) pitch and loudness and (b) hue, saturation, and brightness are true psychological dimensions and yet constitute integral dimensions in just this sense. Recent challenges provided by R. D. Melara, L. E. Marks, and their colleagues are shown to be based on narrow and faulty interpretations of evidence for privileged axes. They are also undermined by strong evidence of the holistic processing of pitch and loudness and of the dimensions of color that emerge within both their own data and the larger literature. The traditional view--including the strong claim that integrality entails mandatory holistic processing--continues to fare very well as an account of a substantial and varied set of findings.

Perception of acoustic correlates of major phrasal units by young infants.

How might young learners parse speech into linguistically relevant units? Sensitivity to prosodic markers of these segments is one possibility. Seven experiments examined infants' sensitivity to acoustic correlates of phrasal units in English. The results suggest that: (a) 9 month olds, but not 6 month olds, are attuned to cues that differentially mark speech that is artificially segmented at linguistically COINCIDENT as opposed to NONCOINCIDENT boundaries (Experiments 1 and 2); (b) the pattern holds across both subject phrases and predicate phrases and across samples of both Child- and Adult-directed speech (Experiments 3, 4, and 7); and (c) both 9 month olds and adults show the sensitivity even when most phonetic information is removed by low-pass filtering (Experiments 5 and (6). Acoustic analyses suggest that pitch changes and in some cases durational changes are potential cues that infants might be using to make their discriminations. These findings are discussed with respect to their implications for theories of language acquisition.

High resolution fluoride profiles of artificial in vitro lesions treated with fluoride dentifrices and mouthrinses during pH cycling conditions.

A pH cycling model which incorporated a severe demineralization component was used to evaluate fluoride uptake and lesion progression for each of a NaF-based dentifrice, NaF-based mouthrinse and a monofluorophosphate (MFP)-based dentifrice. Simultaneous transverse fluoride and calcium profiles across the resulting artificial lesions were obtained using a proton microprobe technique with a resolution of approximately 10 microns. Longitudinal microhardness testing and proton microprobe calcium profiles were used to determine the extent of lesion progression (delta Z) with respect to untreated controls. Under the pH cycling conditions of the present study, the NaF dentifrice and mouthwash were observed to have a considerably higher uptake of fluoride in the lesion than the MFP dentifrice. Although the mineral content profiles of the lesions differed for treatments with each of the fluoride products, the differences were not significantly different in this model.

Crystallographic changes in calcium phosphates during plasma-spraying.

Coating hydroxyapatite (HA) onto metal implant surfaces using the plasma-spraying technique has been investigated in several laboratories as a means of improving the mechanical properties of the bulk ceramic. This study describes crystallographic changes which can occur during the plasma-spraying of calcium phosphate powders. A precipitated calcium-deficient apatite and a high temperature near-stoichiometric HA were each sprayed onto metal substrate in an argon plasma using several hydrogen gas flow conditions at various temperatures. The surfaces were examined by X-ray diffraction and scanning electron microscopy. The plasma-sprayed products were identified as a mixture of calcium phosphates including HA, beta-tricalcium phosphate (beta-TCP) and calcium oxide. Stoichiometric HA when plasma-sprayed showed the least (5%) degradation. Since beta-TCP is more resorbable than HA in vivo, varying the HA/beta-TCP ratio on the plasma-sprayed surface may provide a method to control surface dissolution of the coating.

When experimental findings conflict with everyday observations: reflections on children's category learning.

Attempts to reconcile the ease with which young children naturally learn everyday categories with their frequent difficulty in acquiring artificial categories in the laboratory have taken different forms. Kemler Nelson suggested that one reason for the discrepancy may be that many everyday object categories have a family-resemblance structure that can be learned by means of a holistic mode of processing. While Ward et al. have recently questioned this account of why children learn family-resemblance categories easily, conclusions based on their laboratory data fail to provide a good explanation of the real-world case. Accordingly, it is suggested that the laboratory family-resemblance task used by these previous investigators may be unrepresentative and may fail to mimic crucial aspects of the everyday category-learning context. It is also suggested that aspects of Ward et al.'s methodology may lead them to underestimate holistic (or nonselective) processing.