bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid Fluctuations in Rat Barrel Cortex Plasticity
Authors: Erchova Irina A. , Diamond Mathew E.
Published: June 2004

Neuronal populations in the sensory cortex exhibit fluctuations in excitability, and the present experiments tested the hypothesis that these variations coincide with peaks and troughs in cortical modifiability. The activity of multiunit neuronal clusters under light urethane anesthesia was recorded through 100-microelectrode arrays implanted in the infragranular layers of rat barrel cortex. Spontaneous activity was characterized by “bursts” of spikes, synchronized across the barrel cortex. This allowed activity at one selected electrode to be taken as a reliable monitor of widespread cortical bursts. We used spikes at the selected electrode to trigger stimulation of two pairs of whiskers during a 50 min conditioning procedure: (1) for the “burst-conditioned” whisker pair, each stimulus was delivered 1 msec after the triggering spike, activating cortex coincident with the burst; and (2) for the “interburst-conditioned” whisker pair, each stimulus was delivered 300 msec after the triggering spike, activating cortex during the trough between bursts. The cross-correlation between cortical neurons in the pairs of columns matching the stimulated whisker pairs was estimated after the termination of the conditioning procedure. Conditioning produced a twofold increase in the degree of co-firing between infragranular neurons in columns receiving burst-conditioned costimulation but no significant change in connectivity between infragranular neurons in columns receiving interburst-conditioned costimulation, although the two pairs of columns received an equal number of sensory inputs. These findings suggest that the strength of co-activity between columns in the barrel cortex can be modified by sensory input patterns during discrete, intermittent intervals time-locked to bursts.
Rapid, Hierarchical Modulation of Vocal Patterning by Steroid Hormones
Authors: Remage-Healey Luke , Bass Andrew H.
Published: June 2004

Vocal control systems have been identified in all major groups of jawed vertebrates. Although steroid hormones are instrumental in the long-term development and maintenance of neural structures underlying vocalization, it is unknown whether steroids rapidly modulate the neural activity of vocal motor systems. The midshipman fish generates advertisement and agonistic calls that mainly differ in duration. A descending midbrain pathway activates a hindbrain-spinal vocal circuit that directly establishes the discharge frequency and duration of the rhythmic vocal motor volley. This vocal motor output, which can be monitored from occipital nerve roots, directly determines the rate and duration of contraction of a pair of sonic muscles and, in turn, the fundamental frequency and duration of vocalizations. Here, we demonstrate that the duration of the vocal motor volley, or fictive vocalization, is rapidly responsive to steroid hormones, including androgens, estrogens, and glucocorticoids. These responses are consistent, in part, with a nongenomic mechanism and are steroid specific at the receptor level, suggesting the possibility of multiple membrane-bound receptor populations. We also show, using intact and semi-intact preparations, that steroids hierarchically modulate fictive vocalizations; whereas the hindbrain-spinal region is both necessary and sufficient for rapid (within 5 min) effects on duration, descending midbrain input is necessary for maintenance (up to 120 min) of these effects. The conserved nature of vertebrate vocal motor systems suggests that the neuroendocrine principles outlined in this study may be a fundamental feature of all vocal vertebrates.
A Novel Role of Lactosylceramide in the Regulation of Lipopolysaccharide/Interferon-γ-Mediated Inducible Nitric Oxide Synthase Gene Expression: Implications for Neuroinflammatory Diseases
Authors: Pannu Ravinder , Won Je-Seong , Khan Mushfiquddin , Singh Avtar K. , Singh Inderjit
Published: June 2004

In the present study a possible role of glycosphingolipids (GSLs) in inducible nitric oxide synthase (iNOS) gene expression and nitric oxide (NO) production after spinal cord injury (SCI) in rats has been established. In primary rat astrocytes lipopolysaccharide (LPS) and interferon-γ (IFN-γ) treatment increased the intracellular levels of lactosylceramide (LacCer) and induced iNOS gene expression.d-Threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol·HCI (PDMP), a glucosylceramide synthase and LacCer synthase (galactosyltransferase, GalT-2) inhibitor, inhibited LPS/IFN-γ induced iNOS expression, which was reversed by exogenously supplied LacCer, but not by other glycosphingolipids. LPS/IFN-γ caused a rapid increase in the activity of GalT-2 and synthesis of LacCer. Silencing of GalT-2 gene with the use of antisense oligonucleotides resulted in decreased LPS/IFN-γ-induced iNOS, TNF-α, and IL-1β gene expression. The PDMP-mediated reduction in LacCer production and inhibition of iNOS expression correlated with decreased Ras and ERK1/2 activation along with decreased IκB phosphorylation, NF-κB DNA binding activity, and NF-κB-luciferase reporter activity. LacCer-mediated Ras activation was redox-mediated and was attenuated by antioxidantsN-acetyl cysteine (NAC) and pyrrolidine dithiocarbamate (PDTC).In vivoadministration of PDMP after SCI resulted in improved functional outcome (Basso, Beattie, Bresnahan score); inhibition of iNOS, TNF-α, and IL-1β expression; decreased neuronal apoptosis; and decreased tissue necrosis and demyelination. Thein vivostudies supported the conclusions drawn from cell culture studies and provided evidence for the possible role of GalT-2 and LacCer in SCI-induced inflammation and pathology. To our knowledge this is the first report of a role of LacCer in iNOS expression and the advantage of GSL depletion in attenuating post-SCI inflammation to improve the outcome of SCI.
Prophylactic Creatine Administration Mediates Neuroprotection in Cerebral Ischemia in Mice
Authors: Zhu Shan , Li Mingwei , Figueroa Bryan E. , Liu Aijian , Stavrovskaya Irina G. , Pasinelli Piera , Beal M. Flint , Brown Robert H. , Kristal Bruce S. , Ferrante Robert J. , Friedlander Robert M.
Published: June 2004

Creatine mediates remarkable neuroprotection in experimental models of amyotrophic lateral sclerosis, Huntington's disease, Parkinson's disease, and traumatic brain injury. Because caspase-mediated pathways are shared functional mechanistic components in these diseases, as well as in ischemia, we evaluated the effect of creatine supplementation on an experimental stroke model. Oral creatine administration resulted in a remarkable reduction in ischemic brain infarction and neuroprotection after cerebral ischemia in mice. Postischemic caspase-3 activation and cytochromecrelease were significantly reduced in creatine-treated mice. Creatine administration buffered ischemia-mediated cerebral ATP depletion. These data provide the first direct correlation between the preservation of bioenergetic cellular status and the inhibition of activation of caspase cell-death pathwaysin vivo. An alternative explanation to our findings is that creatine is neuroprotective through other mechanisms that are independent of mitochondrial cell-death pathways, and therefore postischemic ATP preservation is the result of tissue spearing. Given its safety record, creatine might be considered as a novel therapeutic agent for inhibition of ischemic brain injury in humans. Prophylactic creatine supplementation, similar to what is recommended for an agent such as aspirin, may be considered for patients in high stroke-risk categories.
Double Dissociation between the Effects of Peri-Postrhinal Cortex and Hippocampal Lesions on Tests of Object Recognition and Spatial Memory: Heterogeneity of Function within the Temporal Lobe
Authors: Winters Boyer D. , Forwood Suzanna E. , Cowell Rosemary A. , Saksida Lisa M. , Bussey Timothy J.
Published: June 2004

It is widely believed that declarative memory is mediated by a medial temporal lobe memory system consisting of several distinct structures, including the hippocampus and perirhinal cortex. The strong version of this view assumes a high degree of functional homogeneity and serial organization within the medial temporal lobe, such that double dissociations between individual structures should not be possible. In the present study, we tested for a functional double dissociation between the hippocampus and peri-postrhinal cortex in a single experiment. Rats with bilateral excitotoxic lesions of either the hippocampus or peri-postrhinal cortex were assessed in tests of spatial memory (radial maze) and object recognition memory. For the latter, the spontaneous object recognition task was conducted in a modified apparatus designed to minimize the potentially confounding influence of spatial and contextual factors. A clear functional double dissociation was observed: rats with hippocampal lesions were impaired relative to controls and those with peripostrhinal cortex lesions on the spatial memory task, whereas rats with peri-postrhinal lesions were impaired relative to the hippocampal and control groups in object recognition. These results provide strong evidence in favor of heterogeneity and independence of function within the temporal lobe.
Spike Synchronization in the Cortex-Basal Ganglia Networks of Parkinsonian Primates Reflects Global Dynamics of the Local Field Potentials
Authors: Goldberg Joshua A. , Rokni Uri , Boraud Thomas , Vaadia Eilon , Bergman Hagai
Published: June 2004

Cortical local field potentials (LFPs) reflect synaptic potentials and accordingly correlate with neuronal discharge. Because LFPs are coherent across substantial cortical areas, we hypothesized that cortical spike correlations could be predicted from them. Because LFPs recorded in the basal ganglia (BG) are also correlated with neuronal discharge and are clinically accessible in Parkinson's disease patients, we were interested in testing this hypothesis in the BG, as well. We recorded LFPs and unit discharge from multiple electrodes, which were placed in primary motor cortex or in the basal ganglia (striatum and pallidum) of two monkeys before and after rendering them parkinsonian with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. We used the method of partial spectra to construct LFP predictors of the spike cross-correlation functions (CCFs). The predicted CCF is an estimate of the correlation between two neurons under the assumption that their association is explained solely by the association of each with the LFP recorded on a third electrode. In the normal condition, the predictors account for cortical rate covariations but not for the association among the tonically active neurons of the striatum. In the parkinsonian condition, with the appearance of 10 Hz oscillations throughout the cortex-basal ganglia networks, the LFP predictors account remarkably better for the CCFs in both the cortex and the basal ganglia. We propose that, in the parkinsonian condition, the cortex-basal ganglia networks are more tightly related to global modes of brain dynamics that are echoed in the LFP.
Hippocampal Synapses Depend on Hippocampal Estrogen Synthesis
Authors: Kretz Oliver , Fester Lars , Wehrenberg Uwe , Zhou Lepu , Brauckmann Silke , Zhao Shanting , Prange-Kiel Janine , Naumann Thomas , Jarry Hubertus , Frotscher Michael , Rune Gabriele M.
Published: June 2004

Estrogens have been described to induce synaptogenesis in principal neurons of the hippocampus and have been shown to be synthesized and released by exactly these neurons. Here, we have focused on the significance of local estrogen synthesis on spine synapse formation and the synthesis of synaptic proteins. To this end, we reduced hippocampal estrogen synthesisin vitrowith letrozole, a reversible nonsteroidal aromatase inhibitor. In hippocampal slice cultures, letrozole treatment resulted in a dose-dependent decrease of 17β-estradiol as quantified by RIA. This was accompanied by a significant decrease in the density of spine synapses and in the number of presynaptic boutons. Quantitative immunohistochemistry revealed a downregulation of spinophilin, a marker of dendritic spines, and synaptophysin, a protein of presynaptic vesicles, in response to letrozole. Surprisingly, no increase in the density of spines, boutons, and synapses and in spinophilin expression was seen after application of estradiol to the medium of cultures that had not been treated with letrozole. However, synaptophysin expression was upregulated under these conditions. Our results point to an essential role of endogenous hippocampal estrogen synthesis in the maintenance of hippocampal spine synapses.
Rescue of Mesencephalic Dopaminergic Neurons in Culture by Low-Level Stimulation of Voltage-Gated Sodium Channels
Authors: Salthun-Lassalle Bénédicte , Hirsch Etienne C. , Wolfart Jakob , Ruberg Merle , Michel Patrick P.
Published: June 2004

We used a model system in which dopaminergic (DA) neurons from embryonic rat mesencephalon undergo spontaneous and selective degeneration as they develop in culture. Here, we show that DA cell loss can be prevented efficiently by low concentrations of the Na+channel agonist veratridine. The survival promoting effect of veratridine was reproduced by, but independent of, glial cell line-derived neurotrophic factor. Neuroprotection by veratridine was exquisitely specific to DA neurons, short-lived after withdrawal, and abolished by tetrodotoxin, indicating that activation of voltage-gated Na+channels was crucially involved. Calcium measurements showed that veratridine-induced Na+influx was necessary to maintain intracellular Ca2+within a neuroprotective range through the stimulation of low-voltage activated T-type calcium channels, a mechanism that was distinct from that elicited by high K+-evoked depolarization. Interestingly, increasing neuronal excitability by treatment with apamin, an inhibitor of Ca2+-activated K+channels, or with ouabain, a blocker of the Na+/K+-ATPase pump, was also neuroprotective by a mechanism involving T-type calcium channel activation. These results support the idea that mesencephalic DA neurons depend primarily on excitatory input for their survival during development.
Food Additives
Authors: Somogyi Laszlo P.
Published: June 2004

Food additives may be looked upon as minor ingredients incorporated into foods to affect their properties in some desired way. Most commonly, the effects desired relate to flavor, texture, color, nutritive value, or stability in storage. Food additives are defined and closely regulated at the national level.

This chapter provides a brief overview of 27 functional food additive categories, excluding bulk ingredients such as flour, sugar, fats, and oils. These categories comprise hundreds of individual compounds, representing the majority of those common us in the food system. Typical food applications of each additive are identified, and the important technical and functional properties are described.

While there are many differences in food tastes and preferences among the global population, the major trends driving the food additive industry appear to be very similar in all regions: concern over food safety, health and nutrition, and desire for convenience.

These trends will expand the use of food additives, especially those of natural origin. The global market for food additives exceeded $20 billion in 2003, and it is expected to increase at an annual rate of 3–3.5% during the next 5 years.
Defining Collaborative Partnerships
Authors: Saltiel Iris M.
Published: June 2004

The author explores the nature, scope, and meaning of collaborative partnerships
through a discussion of the concepts and their appearance in the
literature.
Adult Students as Partners in Formal Study
Authors: Saltiel Iris M.
Published: June 2004

The dynamics of the relationships among peers in formal education settings
are presented and explained from the perspective of a collaborative partnership
in learning.
Teaching‐Learning Partnerships in the Arts
Authors: Sgroi Angela
Published: June 2004

Insights are drawn from the findings of a qualitative study exploring the
interactive and complex nature of collaborative learning relationships
between teachers and learners in the arts.
Silent Partner: The Power Behind the Throne
Authors: Owenby Phillip H.
Published: June 2004

Virginia Heinlein provided ideas, information, and technical background
necessary for the development of Robert A. Heinlein's science fiction writings.
This chapter examines their relationship and discusses Virginia as an
example of a “silent” collaborative partner.
Collaborative Learning: People Laboring Together to Construct Knowledge
Authors: Peters John M. , Armstrong Joseph L.
Published: June 2004

The authors explore issues and concerns that can emerge when collaborative
learning is employed in adult education settings. They present different
approaches to teaching that can promote or limit opportunities for collaborative
learning.
The Topsfield Foundation: Fostering Democratic Community Building Through Face‐to‐Face Dialogue
Authors: Flavin‐McDonald Catherine , Barrett Molly Holme
Published: June 2004

The authors interview Paul Aicher, founder of the Topsfield Foundation, Inc., and Martha McCoy, executive director of the Study Circles Resource Center, about the challenges of creating an effective, replicable model for citizen engagement through communitywide study circle programs.
The Dutch Experiment in Developing Adult Creativity
Authors: Haanstra Folkert H.
Published: June 2004

The philosophy behind the creativity centers in The Netherlands has been shifting between a focus on the intrinsic values of art itself and the instrumental use of art for developmental and social purposes.
Dialogue and Collaboration as Keys to Building Innovative Educational Initiatives in a Knowledge‐Based Economy
Authors: Walshok Mary Lindenstein
Published: June 2004

Universities operating in a knowledge‐based economy must approach problem solving using interdisciplinary and cross‐professional perspectives.
Adult Learning: Moving Toward More Inclusive Theories and Practices
Authors: Amstutz Donna D.
Published: June 2004

Theories of adult learning are evolving from individual emphases to the construction of meaning in a social and cultural context.
The Quest for Visibility in Adult Education: The Hispanic Experience
Authors: Jeria Jorge
Published: June 2004

Because human capital ideological assumptions drive most adult education programs serving Hispanics, the real social needs of Hispanics are overlooked in most adult educational programs.
Navajo Language and Culture in Adult Education
Authors: Lockhard Louise
Published: June 2004

Examples of culturally relevant education programs for Navajo adults are discussed in terms of program particulars and participants.
Culturally Relevant Adult Education: Key Themes and Common Purposes
Authors: Guy Talmadge C.
Published: June 2004

Key themes and purposes of culturally relevant adult education are discussed.
Research on Adult Literacy Education in the Welfare‐to‐Work Transition
Authors: Fisher James C.
Published: June 2004

This chapter discusses empirical research on former welfare recipients and programs designed to serve them in the welfare‐to‐work transition.
Continuum of Literacy Program Models: Alternative Approaches for Low‐Literate Welfare Recipients
Authors: Martin Larry G.
Published: June 2004

This chapter defines the parameters and limitations of the academic model of adult literacy program development and presents a framework that includes three other approaches: situated context and cognition, literacy integrated with soft skills, and literacy integrated with occupational skills.
The New Role of Community‐Based Agencies
Authors: Folkman Daniel V. , Rai Kalyani
Published: June 2004

This chapter provides a descriptive profile of several community‐based programs that have responded to changes in their practice environment brought on by welfare reform and demands for workforce development.
New Skills for Literacy Educators
Authors: Dirkx John M.
Published: June 2004

This chapter explores the implications for literacy educators of changes in curricula and program implememtation stemming from welfare reform and workforce development.
Our Complex Human Body: Biological Development Explored
Authors: Mott Vivian W.
Published: June 2004

This chapter focuses on concepts and theories of human aging and introduces current thought regarding the interaction and interdependance of various influences on physical well‐being.
Gender Development and Gendered Adult Development
Authors: Ross‐Gordon Jovita M.
Published: June 2004

Although women's and men's sociocultural experiences typically lead them to develop into adulthood via differing pathways and with different strengths, the challenge of adult development is one of becoming fully integrated person.
Racial and Ethnic Identity and Development
Authors: Chávez Alicia Fedelina , Guido‐DiBrito Florence
Published: June 2004

This chapter explores how racial and ethnic identity develops and how a sensitivity to this process can improve adult education.
The Development of Sexual Identity
Authors: Edwards Kathleen , Brooks Ann K.
Published: June 2004

Sexual identity is one of the most importand and intriguing, yet least understood, aspects of human development.
Understanding Adult Development As Narrative
Authors: Rossiter Marsha
Published: June 2004

Narrative offers a way of understanding development in terms of the storied nature of human experience. This chapter discusses the contextual interpretive, retrospective, and temporal dimensions of narrative as applied to adult development.
Development and Learning: Themes and Conclusions
Authors: Caffarella Rosemary S. , Clark M. Carolyn
Published: June 2004

This chapter draws on information from previous chapters to assess where are with our thinking about adult development and to duggest linkages between this theory and learning in adulthood.
Reckoning with the Spiritual Lives of Adult Educators
Authors: Vogel Linda J.
Published: June 2004

Teaching and learning that are holistic must be open to and reckon with the spiritual lives of both adult educators and learners; educators must design processes that invite the involvement of whole persons while honoring the experience of each person in ways that leave room for diversity and mystery.
Learning from Native Adult Education
Authors: Orr Jeffrey A.
Published: June 2004

Adult educators have much to learn from Native peoples' focus on the four directions of the medicine wheel: the emotional, physical, spiritual, and cognitive.
Community Development and Adult Education: Locating Practice in Its Roots
Authors: Bean Wilf E.
Published: June 2004

This chapter describes two cases in which community development, adult education, and spirituality have been interwoven. The author uses these cases to make suggestions for adult education practice.
The Spiritual Dimensions of Lay Ministry Programs
Authors: Zeph Catherine P.
Published: June 2004

Lay ministry education programs attend to the spiritual dimension of their participants' growth whenever principles of adult education are applied. This chapter describes one such program and how its components nourish the spiritual development of its participants.
Trends and Issues in Continuing Professional Education
Authors: Cervero Ronald M.
Published: June 2004

Compared to the initial stages of professional education, systems of continuing education for the professions are in their infancy. In this chapter, four trends and three issues shaping the future of continuing education are identified.
Evaluation of Continuing Professional Education: Toward a Theory of Our Own
Authors: Ottoson Judith M.
Published: June 2004

Program evaluation theory seeks to make the evaluation of continuing professional education a transparent process. This chapter introduces the Situated Evaluation Framework, which situates the learner and knowledge assessment at the junction of the educational context, the practice context, and the evaluation context.
Marketing Realities in Continuing Professional Education
Authors: Craven Ruth F. , DuHamel Martha B.
Published: June 2004

Effective marketing strategies can promote attendance, enhance the satisfaction of registrants, and help continuing professional education programs meet financial goals.
Continuing Professional Education: From Vision to Reality
Authors: Daley Barbara J. , Mott Vivian W.
Published: June 2004

This chapter advocates reframing the vision of continuing professional education so that improvement of professional practice is at the core of service—services that would include market‐driven product lines in education, evaluation, and consultation.
Team Teaching in Adult Higher Education Classrooms: Toward Collaborative Knowledge Construction
Authors: Harris Candace , Harvey Anne N. C.
Published: June 2004

The demands of co‐teaching in higher education are offset by the benefits
that teachers and learners derive from collaborative knowledge
construction.
Learning Strategies for Learning Technologies
Authors: Olgren Christine H.
Published: June 2004

A review of learning strategies shows why it is necessary to take a learner‐centered view before thinking about technology.
Extending Information Literacy in Electronic Environments
Authors: Kerka Sandra
Published: June 2004

Understanding information literacy requires understanding how literacy is changed by electronic technology. Critical literacy is an essential characteristic of information‐literate learners.
Radio as a Learning Technology
Authors: Maskow May
Published: June 2004

A recent initiative in educational radio successfully used a new design—a doculecture—to attract credit learners and interested members of the public.
Constructivist Learning on the Web
Authors: Wilson Brent , Lowry May
Published: June 2004

The underlying principles of learning and cognition are the same for all media and learning environments, including the Web. Effective learning can happen on the Web if a few key principles of information design and learner guidance are applied.
MRX42: Two linkage intervals, one in the pericentromeric region and one in Xq26, and the impact for carrier risk estimation
Authors: Golla Astrid , Rost Imma , Jedele Kerry Baldwin , Albert Angelika , Murken Jan , Holinski‐Feder Elke
Published: June 2004

A nonspecific X‐linked mental retardation (MRX) family is reported with four mild to moderately affected males and no intellectual impairment in their obligate carrier mothers. Linkage analysis obtained the same multipoint lod score of 2.08 for two intervals on the X chromosome already reported to be linked to other MRX and syndromic X‐linked mental retardation (XLMR) families: one pericentromeric and the other at Xq26. Since the responsible gene is not yet characterized, haplotyping is presently the only means available for carrier and prenatal testing for this form of MRX. Carrier risk estimation using pedigree and haplotype data for five females at risk is presented, and the difficulties of prenatal diagnosis given linkage to two different regions is discussed. © 2001 Wiley‐Liss, Inc.
Detection of Yersinia pestis DNA in two early medieval skeletal finds from Aschheim (Upper Bavaria, 6th century A.D.)
Authors: Wiechmann Ingrid , Grupe Gisela
Published: June 2004

In the course of a molecular genetic investigation of a double inhumation, presumably a mother/child burial from Aschheim (Upper Bavaria, 6th century A.D.), which included analysis of mitochondrial DNA, molecular sexing, and polymorphic nuclear DNA, Yersinia pestis‐specific DNA was detected. Molecular analyses were performed on DNA extracts obtained from two teeth of one skeleton and four teeth of the other. The use of the primer pair YP12D/YP11R (Raoult et al. [2000] Proc. Natl. Acad. Sci. 97:12800–12803), able to amplify part of the Y. pestis plasmid pPCP1 pla sequence, resulted in amplification products of the expected fragment size. Using BLASTN 2.2.2, the sequences of these amplification products shared 100% identity with that of the modern Y. pestis pla sequence in GenBank, with the exception of one amplification product which revealed a single base substitution. The application of a “suicide PCR” with the independent primer pair YP11D/YP10R (Raoult et al. [2000] Proc. Natl. Acad. Sci. 97:12800–12803) resulted in amplification products which shared a 96–98% homology with that of the modern Y. pestis pla sequence in GenBank. The observed deviations were presumably due to miscoding lesions in the template DNA. No modern Y. pestis DNA was introduced into the institute, and thus no positive controls were carried along. All extraction and PCR controls remained negative. The identification of Y. pestis‐specific DNA sequences in these two skeletons, buried in the second half of the 6th century A.D., constitutes molecularly supported evidence for the presence of Y. pestis, the causative agent of plague, during the first pandemic recorded. Am J Phys Anthropol, 2004. © 2004 Wiley‐Liss, Inc.
Brief communication: Discrimination between European‐American and African‐American children based on deciduous dental metrics and morphology
Authors: Lease Loren R. , Sciulli Paul W.
Published: June 2004

This study employs metric and morphological features of the deciduous dentition for discriminating between European‐American and African‐American children and providing allocation rules (regression equations). Five logistic regression equations are presented, with the percentage of correct allocation to group of between 90.1–92.6%. All five equations employ three metric traits (the mesiodistal diameters of the mandibular deciduous canines and anterior and posterior deciduous premolars) and one morphological feature (cusp number of the maxillary deciduous anterior premolar). In addition to these four variables, only two or three additional morphological features are added in carious combinations in the final equations. Correct allocation to group is 4–12% greater when combining metric and morphological features compared to using the features separately. Am J Phys Anthropol, 2004. © 2004 Wiley‐Liss, Inc.
Physical growth and nutritional status of Tsimane' Amerindian children of lowland Bolivia
Authors: Foster Z. , Byron E. , Reyes‐García V. , Huanca T. , Vadez V. , Apaza L. , Pérez E. , Tanner S. , Gutierrez Y. , Sandstrom B. , Yakhedts A. , Osborn C. , Godoy R.A. , Leonard W.R.
Published: June 2004

This study examines patterns of growth and nutritional status of indigenous Tsimane' children under 9 years of age (n = 199 boys and 210 girls), based on a cross‐sectional sample from 58 villages from the Beni Deparment of lowland Bolivia. Compared with US children, Tsimane' children are quite short, with linear growth tracking at or below the US 5th centile in both sexes. The prevalence of low height‐for‐age (“stunting;” HA Z‐scores ≤−2) is 52% in boys and 43% in girls. In contrast, weight‐for‐height in Tsimane' children approximates the US median, with the prevalence of low weight‐for‐height (“wasting”; WH Z‐scores ≤−2) being only 4% and 6% in boys and girls, respectively. Tsimane' boys and girls are leaner than their US peers, but their levels of body fatness are not so low as to indicate severe energy stress. Arm muscularity of Tsimane' children is similar to that of their US age peers, and this suggests that they are not experiencing acute protein malnutrition. Variation in measures of nutritional status of Tsimane' children is modestly correlated with village‐level differences. Degree of isolation, as measured by distance to urban centers or to primary forest, was not a strong predictor of children's anthropometric status. Rather, in both boys and girls, nutritional status was most strongly associated with number of teachers in the village, a measure of access to education. Comparative analyses indicate that high levels of statural growth stunting are common among indigenous populations throughout lowland South America. This problem appears to be largely attributable to poor dietary quality (diets low in key micronutrients) and high disease loads. Further research is needed to identify the specific causes and potential interventions for the high rates of childhood growth stunting in this region. Am J Phys Anthropol 126:343–351, 2005. © 2004 Wiley‐Liss, Inc.
N2O Reduction by the μ4‐Sulfide‐Bridged Tetranuclear CuZ Cluster Active Site
Authors: Chen Peng , Gorelsky Serge I. , Ghosh Somdatta , Solomon Edward I.
Published: June 2004

Nitrous oxide (N2O) reduction is a chemical challenge both in the selective oxidation of organic substrates by N2O and in the removal of N2O as a green‐house gas. The reduction of N2O is thermodynamically favorable but kinetically inert, and requires activating transition‐metal centers. In biological systems, N2O reduction is the last step in the denitrification process of the bacterial nitrogen cycle and is accomplished by the enzyme nitrous oxide reductase, whose active site consists of a μ4‐sulfide‐bridged tetranuclear CuZ cluster which has many unusual spectroscopic features. Recent studies have developed a detailed electronic‐structure description of the resting CuZ cluster, determined its catalytically relevant state, and provided insight into the role of this tetranuclear copper cluster in N2O activation and reduction.
Synthesis and characterization of ultraviolet‐curable fluorinated polydimethylsiloxanes as ultraviolet‐transparent coatings for optical fiber gratings
Authors: Colomines GaëL , Andre Sébastien , Andrieu Xavier , Rousseau Alain , Boutevin Bernard
Published: June 2004

Synthesis of photocrosslinkable fluorinated polydimethylsiloxane (PDMS) was carried out through the direct hydrosilylation of allyl 2‐(perfluorohexyl)ethyl ether with copoly(dimethyl methyl hydro siloxane). The hydrosilylation of the fluorinated allyl ether allowed the introduction of fluorinated groups onto the polysiloxane backbone. Then, a second hydrosilylation of allyl methacrylate led to PDMS bearing both fluorinated and photocrosslinkable groups. The ratio between fluorinated groups and allyl methacrylate groups allowed us to tune the refractive index of the resin without changing thermal properties. Formulations containing fluorinated PDMS were ultraviolet‐cured, and their ultraviolet transparency and Yttrium Aluminium Garnet (YAG) laser resistance were investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2021–2026, 2003
Syntheses of chemical‐modified cellulose obtained from waste pulp
Authors: Hadano Shingo , Onimura Kenjiro , Tsutsumi Hiromori , Yamasaki Hirohito , Oishi Tsutomu
Published: June 2004

Chemical‐modified pulps were synthesized from four types of waste pulps (Pulp1–4) and succinic anhydride (SAn) or maleic anhydride (MAn). The solubility of the modified pulps was evaluated in common organic solvents, and their thermal properties were investigated by DSC measurement. The solubility of the modified pulps increased with an increasing degree of substitution (DS). However, no Tg or Tm of these modified pulps was confirmed. Pulps and modified pulps were graft‐polymerized with ε‐caprolactone (CL) in bulk and in DMAc/LiCl. Although the solubility of the graft copolymers was similar to modified pulps, some graft copolymers showed a Tg by the introduction of CL units. In the bulk, graft copolymers obtained from modified pulps and nonmodified pulps showed a Tg of about 75°C and no Tg, respectively. In DMAc/LiCl, the obtained graft copolymers from both modified and nonmodified pulps exhibited a Tg of 95–110°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2059–2065, 2003
Effect of filler treatment and crosslinking on mechanical and dynamic mechanical properties and electrical conductivity of carbon black‐filled ethylene–vinyl acetate copolymer composites
Authors: Das N. C. , Chaki T. K. , Khastgir D.
Published: June 2004

Mechanical, dynamic mechanical, and electrical conductivity of conductive carbon black‐filled ethylene–vinyl acetate (EVA; 28% VA) composites were investigated. The above‐mentioned properties were also measured when carbon black was treated with nitric acid before addition to the EVA matrix. It was found that acid‐treated carbon black exhibits a higher filler–polymer interaction and this was reflected in the improvement of the mechanical properties and the modification of electrical conductivity of these composites, especially when measured against the temperature. The effect of curing of the polymer matrix on the mechanical properties and electrical conductivity was also investigated. It was found that the introduction of crosslinks in the polymer matrix improves its mechanical properties as well as the thermal stability of its electrical conductivity. The electrical conductivity of ethylene propylene diene (EPDM) and an EVA–EPDM (50/50) blend filled with carbon black were also studied for comparison. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2073–2082, 2003
Studies on polyacrylates containing pendant ligand with carbonyl and hydroxyl functions and their divalent metal complexes
Authors: Kaliyappan T. , Rajagopan S. , Kannan P.
Published: June 2004

A series of monomers were prepared by reacting (meth)acryloyl chloride with 2,4‐dihydroxybenzophenone, 2,4‐dihydroxybenzaldehyde, and 2,4‐dihydroxyacetophenone, respectively. The monomers were polymerized in dimethylformamide (DMF) at 70°C using benzoyl peroxide as an initiator. Polymer–metal complexes were obtained from DMF solutions of polymers with an aqueous solution of metal ions. The polymers and polymer–metal complexes were characterized by elemental analysis and spectral studies. The IR spectra of these complexes suggest that the metals are coordinated through the oxygen of the carbonyl group and the oxygen of the phenolic–OH group. The electronic spectra, electron paramagnetic resonance (EPR) spectra, and magnetic moments of polychelates showed an octahedral and square planar structure for Ni(II) and Cu(II) complexes, respectively. X‐ray diffraction studies revealed that polychelates are highly crystalline. The thermal and electrical properties, catalytic activity, and structure–property relationships are discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2083–2090, 2003
Polymer‐immobilized cyclodextrin trapping of model organic pollutants in flowing water streams
Authors: Orprecio Ricardo , Evans Christopher H.
Published: June 2004

Epichlorohydrin‐crosslinked β‐cyclodextrin polymers (BCDPs) were prepared and characterized by Fourier transform infrared. Beads of the BCDPs were used to pack a column for trapping organic contaminants in flowing water (flow rate = 5–32 mL/min). The contaminants were naphthalene (a model for polyaromatic hydrocarbons), naproxen (a model for pollutants of pharmaceutical origin), and 2‐naphthol (a model for pesticides with pH‐dependent ionization states). The trapping efficiencies were determined with fluorescence spectroscopy as the analytical technique. The best trapping efficiencies were obtained for BCDPs with a nominal cyclodextrin/epichlorohydrin ratio of 1:29. Trapping was highly efficient for naphthalene (98%) and 2‐naphthol (70%), but it was much less efficient for naproxen (18%). Possible causes for these differences were examined. The trapped organics could be flushed from the column with an ethanol wash. The recovery of the organics with this approach was very good (>95%). This simple column design, made of inexpensive and reusable materials, has potential applications in water remediation and water sampling. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2103–2110, 2003
High‐density polyethylene foams. I. Polymer and foam characterization
Authors: Zhang Yaolin , Rodrigue Denis , Ait‐Kadi Abdellatif
Published: June 2004

The density and morphology of closed‐cell high‐density foams were investigated with four different molecular weights of high‐density polyethylene (HDPE). The characterization of polyethylene via rheological methods was used to determine its influence on foam density and morphology. We found that foaming grade decreased with increasing molecular weight and increased with blowing agent content. The average cell size was also a strong function of molecular weight and blowing agent content. Increasing both the molecular weight and amount of blowing agent decreased the cell size. Cell size also increased for our lowest molecular weight HDPE but decreased for the others. Cell density also increased with increasing HDPE molecular weight. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2111–2119, 2003
Isothermal phase diagrams and phase‐inversion behavior of poly(vinylidene fluoride)/solvents/additives/water systems
Authors: Yeow M. L. , Liu Y. T. , Li K.
Published: June 2004

Isothermal ternary phase diagrams of poly(vinylidene fluoride) (PVDF)/solvents/nonsolvent systems were produced using four different solvents, N,N‐dimethylacetamide (DMAc), 1‐methyl‐2‐pyrrolidinone (NMP), N,N‐dimethylformamide (DMF), and triethyl phosphate (TEP), and using water as a nonsolvent. The effects of the additives polyvinylpyrrolidone (PVP, Mw = 10,000), ethanol, and lithium perchlorate (LiClO4) on the phase‐inversion behavior of PVDF/DMAc/water ternary system were investigated, with additive concentrations of 2 and 6 wt %, at temperatures of 25 and 70°C, respectively. Ethanol, glycerol, and water were used to study the cloud points of 10, 15, and 20 wt % PVDF/DMAc concentrations, at solution temperatures ranging from 30 to 70°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2150–2155, 2003
Effect of mica addition on the properties of natural rubber and polybutadiene rubber vulcanizates
Authors: Castro Daniele F. , Suarez João Carlos Miguez , Nunes Regina C. R. , Visconte Leila L. Y.
Published: June 2004

The rheometric, mechanical, and dynamic mechanical properties as well as fracture surfaces of natural rubber–mica and polybutadiene rubber–mica vulcanizates were studied. Mica was used in the range of 0–30 phr and the rheometric study was carried out at 160°C. The results indicate that the mechanical properties are improved as filler addition increases. Dynamic mechanical testing was used to analyze the observed mechanical behavior. The two elastomers showed different fracture behaviors. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2156–2162, 2003
Electrochemical preparation of soluble sulfonated polymers and aniline copolymers of aniline sulfonic acids in dimethylsulfoxide
Authors: Şahin Yücel , Pekmez Kadir , Yıldız Attila
Published: June 2004

Fully sulfonated polyaniline was produced during the electrochemical polymerization of orthanilic, metanilic, and sulfanilic acids in dimethylsulfoxide (DMSO). The dry conductivity values of the polymers obtained from the above three isomers of aminobenzene sulfonic acids were found to be 0.052, 0.087, and 0.009 S/cm, respectively. Furthermore, partially sulfonated copolymers of these aniline sulfonic acids and aniline were also synthesized electrochemically in DMSO. The dry conductivity values of the copolymers obtained from these three acids were found to be 0.094, 0.26, and 0.033 S/cm, respectively. The polymers and copolymers are soluble in water, DMSO, and N‐methyl‐2‐pyrrolidone. The structure and properties of these polymers and copolymers were elucidated using cyclic voltammetry, scanning electron microscopy, Fourier transform infrared, elemental analysis, and ultraviolet‐visible absorption spectroscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2163–2169, 2003
Durable antimicrobial nylon 66 fabrics: Ionic interactions with quaternary ammonium salts
Authors: Son Young‐A , Sun Gang
Published: June 2004

Acidic or basic dyeing of fibers involves ionic interactions between reactive groups on the polymers and dye molecules. Such interactions can be utilized in the functional finishing of fabrics. This article discusses a new approach of employing the ionic interactions between anionic carboxylic end groups of polyamides and cationic quaternary ammonium salts in the chemical finishing of nylon fabrics to achieve desired durable antimicrobial functions. The finishing conditions such as pH, finishing temperature, and time were studied, and the pH of the finishing bath was very critical in affecting the ionic interactions and thus exhaustion of the salts on the fabrics. The finishing process should be carried out at a temperature above the glass transition temperature of nylon 66. The finished products demonstrated excellent durability of antimicrobial functions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2194–2199, 2003
Synthesis and characterization of poly(ester urethane)/nitrokonjac glucomannan semi‐interpenetrating polymer networks
Authors: Gao Shanjun , Zhang Lina , Cao Jinli
Published: June 2004

We prepared novel semi‐interpenetrating polymer network (semi‐IPN) materials by mixing poly(ester urethane), synthesized by the polymerization reaction between poly(ethylene glycol adipate) and toluene diisocyanate in the presence of 2,2‐bis(hydroxyl methyl) propionic acid as an extender, with nitrokonjac glucomannan (NKGM) in tetrahydrofuran and then by crosslinking and curing the mixture at 60°C for 1.5 h. Miscibility and the properties of the sheets were studied by Fourier transition infrared spectroscopy, wide‐angle X‐ray diffraction, differential scanning calorimetry (DSC), and scanning electron microscopy. The results indicate that strong interactions between poly(ester urethane) and NKGM in the semi‐IPN sheets occurred, leading to good miscibility between the two polymers in the whole region of component ratios. When the content of NKGM was 10%, the tensile strength and breaking elongation of the semi‐IPN sheet were simultaneously enhanced to 35 MPa and 960%, respectively, compared with pure polyurethane. The DSC curves showed a low softening temperature for the poly(ester urethane), which resulted in the high elongation. By changing the NKGM amount from 10 to 90%, we prepared a series of composite materials from an elastomer to tough plastics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2224–2228, 2003
Effects of the chirality and functionality of monomers on the holographic gratings formed in photosensitive films
Authors: Liu Jui‐Hsiang , Wu Fuh‐Tsang
Published: June 2004

Photosensitive holographic polymer films were fabricated. Instead of liquid crystals, a nonreactive high‐refractive‐index diphenyl sulfide was mixed with several monomers and an initiator for the preparation of the holographic grating films. To investigate the formation of periodic arrays of the photosensitive refractive‐index modulation films and the effects of the chirality and functionality of monomers on the diffraction efficiency, chiral monomeric (−)‐bornyl acrylate, (+)‐bornyl acrylate, and the racemate (±)‐bornyl acrylate were synthesized and copolymerized with various multifunctional monomers. A reasonable schematic of the photosensitive polymerization mechanism was proposed. The effects of the multifunctional monomers, initiator concentrations, and feed monomer concentrations on the diffraction efficiencies were investigated. The morphologies of the polymer matrices were studied with scanning electron microscopy. Pictures of real light diffraction patterns with 15 grating points were obtained. In comparison with those described in the literature, the diffraction efficiency obtained in this investigation was relatively high. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2246–2254, 2003