bluuebunny/crossref_metadata_2025 huggingface dataset:
Reconstructing impairment of secretory ameloblast function in porcine teeth by analysis of morphological alterations in dental enamel
Authors: Witzel Carsten , Kierdorf Uwe , Dobney Keith , Ervynck Anton , Vanpoucke Sofie , Kierdorf Horst
Published: June 2006

We studied the relationship between the macroscopic appearance of hypoplastic defects in the dental enamel of wild boar and domestic pigs, and microstructural enamel changes, at both the light and the scanning electron microscopic levels. Deviations from normal enamel microstructure were used to reconstruct the functional and related morphological changes of the secretory ameloblasts caused by the action of stress factors during amelogenesis. The deduced reaction pattern of the secretory ameloblasts can be grouped in a sequence of increasingly severe impairments of cell function. The reactions ranged from a slight enhancement of the periodicity of enamel matrix secretion, over a temporary reduction in the amount of secreted enamel matrix, with reduction of the distal portion of the Tomes’ process, to either a temporary or a definite cessation of matrix formation. The results demonstrate that analysis of structural changes in dental enamel allows a detailed reconstruction of the reaction of secretory ameloblasts to stress events, enabling an assessment of duration and intensity of these events. Analysing the deviations from normal enamel microstructure provides a deeper insight into the cellular changes underlying the formation of hypoplastic enamel defects than can be achieved by mere inspection of tooth surface characteristics alone.
Apoptosis during the seasonal spermatogenic cycle of Rana catesbeiana
Authors: Sasso‐Cerri Estela , Cerri Paulo Sérgio , Freymüller Edna , Miraglia Sandra Maria
Published: June 2006

In the bullfrog Rana catesbeiana, testicular weight is constant throughout the year, but the volume densities of germinative and interstitial compartments undergo inverse changes from winter (non‐breeding) to summer (breeding). The occurrence of apoptosis in the seminiferous lobules of bullfrogs was investigated in these two periods using sections stained with haematoxylin and eosin (H&E), the TUNEL (terminal deoxynucleotidyl transferase‐mediated dUTP nick end labelling) method and transmission electron microscopy. TUNEL‐positive cells were observed in the seminiferous lobules, and ultrastructural morphological details confirmed the occurrence of cell death by apoptosis. In summer, the occurrence of several spermatogenic processes (in addition to spermiogenesis and spermiation), and then the overconsumption of Sertoli cell‐derived pro‐survival factors, could be responsible for the increased density of apoptotic cells. Alternatively, the low apoptotic frequency in winter could be related to the constant homeostasis in the germinative compartment given that most lobules are filled with primary spermatocytes. As volume densities of interstitial and germinative compartments undergo inverse seasonal variations through the year, the incidence of apoptosis (in summer) could play a part in controlling the spermatogenic process, maintaining the lobular size when interstitial tissue is maximally developed. In winter, the low apoptotic cell density leads to spermatogenic recrudescence and, thereby, the production of an adequate quantity of spermatozoa for the next breeding period. Thus, apoptosis may participate not only in the maintenance of spermatogenic homeostasis, but also in the cyclical control of the different spermatogenic processes according to seasonal changes of the testicular compartments as a whole.
Dynamic mechanics in the pig mandibular symphysis
Authors: Langenbach G. E. J. , Zhang F. , Herring S. W. , Van Eijden T. M. G. J. , Hannam A. G.
Published: June 2006

During mastication, various biomechanical events occur at the mammalian jaw symphysis. Previously, these events have been studied in the static environment, or by direct recording of surface bone strains. Thus far, however, it has not been possible to demonstrate directly the forces and torques passing through the symphysis in association with dynamically changing muscle tensions. Therefore, we modified a previously published dynamic pig jaw model to predict the forces and torques at the symphysis, and related these to simulated masticatory muscle tensions, and bite, joint and food bolus forces. An artificial rigid joint was modelled at the symphysis, allowing measurements of the tri‐axial forces and torques passing through it. The model successfully confirmed three previously postulated loading patterns at the symphysis. Dorsoventral shear occurred when the lower teeth hit the artificial food bolus. It was associated with balancing‐side jaw adductor forces, and reaction forces from the working‐side bite point. Medial transverse bending occurred during jaw opening, and was associated with bilateral tensions in the lateral pterygoid. Lateral transverse bending (wishboning) occurred at the late stage of the power stroke, and was associated with the actions of the deep and superficial masseters. The largest predicted force was dorsoventral shear force, and the largest torque was a ‘wishboning’ torque about the superoinferior axis. We suggest that dynamic modelling offers a new and powerful method for studying jaw biomechanics, especially when the parameters involved are difficult or impossible to measure in vivo.
Nature's answer to breaching the skin barrier: an innovative development for amputees
Authors: Pendegrass C. J. , Goodship A. E. , Price J. S. , Blunn G. W.
Published: June 2006

The human body has evolved to maintain homeostasis through the covering of skin and mucous membranes, which separate the internal environment from the harsh and variable external milieu. Few structures naturally penetrate these coverings, and teeth are the only exception in human beings. Attempts to breach these barriers, to develop skin‐ penetrating, bone‐anchored amputation prostheses, can lead to opportunist invasion by microorganisms and subsequent infection, which can jeopardize the life of the individual. There are only a few fascinating examples where the integument of other species is interrupted without such dire consequences, and the deer antler is one such case. Deer antlers are cephalic bony appendages arising from the frontal bones of the skull of the males of most deer species, and are true transient skin‐penetrating structures. Antlers are subject to extreme loading during the rutting season and yet the skin–bone barrier remains intact. Here we show how deer antlers can be used as natural analogues for the successful development of specialized orthopaedic amputation prosthetics. We have used quantitative and qualitative findings from a study of the morphology of deer antlers to develop a device that mimics their structure, which creates a tight seal between the implant and the host tissues, for use in amputation prosthetics.
Appositional enamel growth in molars of South African fossil hominids
Authors: Lacruz Rodrigo S. , Bromage Timothy G.
Published: June 2006

Enamel is formed incrementally by the secretory activity of ameloblast cells. Variable stages of secretion result in the formation of structures known as cross striations along enamel prisms, for which experimental data demonstrate a correspondence with daily periods of secretion. Patterns of variation in this daily growth are important to understanding mechanisms of tooth formation and the development of enamel thickness. Transmitted light microscopy (TLM) of histological ground sections and scanning electron microscopy (SEM) of bulk specimens or their surface replicas are the usual methods for investigating cross striations. However, these methods pose some constraints on the study of these features in Plio‐Pleistocene hominid enamel, the specimens of which may only rarely be sectioned for TLM or examined on only their most superficial surfaces for SEM. The recent development of portable confocal scanning optical microscopy (PCSOM) resolves some of the restrictions on fractured enamel surfaces, allowing the visualization of cross striations by direct examination. This technology has been applied here to the study of Australopithecus africanus and Paranthropus robustus hominid molars from the Plio‐Pleistocene of South Africa. We hypothesize that these taxa have increased enamel appositional rates compared with modern humans, because despite having thicker enamelled molars (particularly P. robustus), the enamel crowns of these fossil taxa take an equivalent or reduced amount of time to form. Cross striations were measured in cuspal, lateral and cervical regions of the enamel crowns, and, within each region, the inner, middle and outer zones. Values obtained for A. africanus outer zones of the enamel crown are, in general, lower than those for P. robustus, indicating faster forming enamel in the latter, while both taxa show higher rates of enamel growth than modern humans and the African great apes. This demonstrates a relatively high degree of variability in the mechanisms underlying the development of enamel across taxa.
Plant–plant interactions and environmental change
Authors: Brooker Rob W.
Published: June 2006

Natural systems are being subjected to unprecedented rates of change and unique pressures from a combination of anthropogenic environmental change drivers. Plant–plant interactions are an important part of the mechanisms governing the response of plant species and communities to these drivers. For example, competition plays a central role in mediating the impacts of atmospheric nitrogen deposition, increased atmospheric carbon dioxide concentrations, climate change and invasive nonnative species. Other plant–plant interaction processes are also being recognized as important factors in determining the impacts of environmental change, including facilitation and evolutionary processes associated with plant–plant interactions. However, plant–plant interactions are not the only factors determining the response of species and communities to environmental change drivers – their activity must be placed within the context of the wide range of factors that regulate species, communities and ecosystems. A major research challenge is to understand when plant–plant interactions play a key role in regulating the impact of environmental change drivers, and the type of role that plant–plant interactions play. Although this is a considerable challenge, some areas of current research may provide the starting point to achieving these goals, and should be pursued through large‐scale, integrated, multisite experiments.

Contents

Summary
271

I.
Introduction
272

II.
Plant–plant interactions mediate the impacts of environmental change
273

III.
Plant–plant interactions in context
276

IV.
Understanding variation in the role of plant–plant interactions
278

V.
Concluding remarks
281

Acknowledgements
281

References
281
Intentional modulation of emotional responding to unpleasant pictures: An ERP study
Authors: Moser Jason S. , Hajcak Greg , Bukay Emily , Simons Robert F.
Published: June 2006

Intentionally altering responses to unpleasant stimuli affects physiological and hemodynamic activity associated with emotional and cognitive processing. In the present experiment, we measured the late‐positive potential (LPP) of the visually evoked event‐related brain potential to examine the effects of intentional emotion modulation on electrophysiological correlates of emotional and cognitive processing. Seventeen participants received instructions to view, suppress, and enhance emotional responses to unpleasant stimuli. Results revealed significantly decreased electrophysiological activity during suppression of emotional responses beginning around 250 ms poststimulus and lasting several hundred milliseconds. These data suggest that ERPs are sensitive to emotion modulation/regulation processes.
The antisaccade task as a research tool in psychopathology: A critical review
Authors: Hutton Samuel B. , Ettinger Ulrich
Published: June 2006

The antisaccade task is a measure of volitional control of behavior sensitive to fronto‐striatal dysfunction. Here we outline important issues concerning antisaccade methodology, consider recent evidence of the cognitive processes and neural mechanisms involved in task performance, and review how the task has been applied to study psychopathology. We conclude that the task yields reliable and sensitive measures of the processes involved in resolving the conflict between volitional and reflexive behavioral responses, a key cognitive deficit relevant to a number of neuropsychiatric conditions. Additionally, antisaccade deficits may reflect genetic liability for schizophrenia. Finally, the ease and accuracy with which the task can be administered, combined with its sensitivity to fronto‐striatal dysfunction and the availability of suitable control conditions, may make it a useful benchmark tool for studies of potential cognitive enhancers.
Sex differences in negative affective response during nicotine withdrawal
Authors: Hogle Joanne M. , Curtin John J.
Published: June 2006

This study examined physiological indicants of the neurobiological mediators of negative affect during acute nicotine withdrawal. Eighty subjects (41 male) were assigned to one of four groups (24‐h deprived or nondeprived dependent smokers, occasional smokers, and nonsmokers) and participated in an instructed fear conditioning paradigm involving cued administration of electric shock. Negative affective response was measured with fear‐potentiated startle during cues that signaled electric shock and during the postcue offset recovery period. Salivary cortisol and self‐report measures were also collected. Fear‐potentiated startle results indicated that affective recovery postcue offset was delayed in nicotine‐deprived women. Nicotine‐deprived women also displayed elevated cortisol levels throughout the fear conditioning procedure.
Beware misleading cues: Perceptual similarity modulates the N2/P3 complex
Authors: Azizian Allen , Freitas Antonio L. , Parvaz Mohammad A. , Squires Nancy K.
Published: June 2006

Event‐related potentials were used to investigate neural processes relating perceptual similarity to action control. To assess whether perceptual overlap among targets and nontargets would modulate the N2/P3 complex, the present study used multiple nontarget categories varying in their targetlike characteristics. Participants made one (relatively rare) response to a low‐probability stimulus (target), and they made a different (relatively common) response to all other stimuli (nontargets). The critical nontarget categories had equivalent probability (.10) but varied in their targetlike characteristics. Supporting the N2 component as sensitive to the strength of conflicting action imperatives, perceptual overlap among targets and nontargets elicited a prominent N2. In contrast, amplitude of the P3 component appeared most sensitive to the extent of cognitive processing needed for categorization.
Willingness to communicate: can online chat help?1
Authors: Freiermuth Mark , Jarrell Douglas
Published: June 2006

This study compared the experiences of small groups of female Japanese university students communicating in English to solve tasks using online chat with those who solved the same tasks in face‐to‐face settings using spoken language. The groups were compared using a counterbalanced research design so that the nine groups consisting of four participants each took part in solving tasks in both the online mode and the traditional face‐to‐face setting. Data gathered from questionnaires, along with an analysis of the discourse produced by students, led to the conclusion that under the conditions in the study, online chatting provided a more comfortable environment, enhancing students’ willingness to communicate. Regarding benefits to the language teacher, online chat provides another fruitful tool to enhance interaction in the target language.
Connecting linguistic description and language teaching: native and learner use of existentialthere1
Authors: Palacios‐Martínez Ignacio , Martínez‐Insua Ana
Published: June 2006

This article emerges from the need to connect linguistic theory and language teaching to find concrete solutions to problems Spanish students confront when learning English. This study looks at existentialthereconstructions taken from the following native and non‐native written English corpora: the International Corpus of Learner English and the Santiago University Learner of English Cor‐pus for the non‐native set, and the Louvain Corpus of Native English Essays,Biber et al. (1999)and a subcorpus of the BNC for the native English group. This contrastive study reveals important differences in the use ofthereconstructions as regards their frequency, structural complexity, polarity and pragmatic value. Important implications for the presentation and the pedagogical treatment of thethereconstructions can be derived from the results.
Land evaluation for forestry: a study of the land requirements for growing Pinus radiata D. Don in the Basque Country, northern Spain
Authors: Olarieta J. R. , Besga G. , Rodríguez‐Ochoa R. , Aizpurua A. , Usón A.
Published: June 2006

Land requirements for the growth of Pinus radiata D. Don were studied in 112 plots by comparing site index (SI) values with land characteristics. The SI at the reference age of 20 years ranged from 10.4 to 32.7 m. The growth of Radiata pine increased as soil rootable depth increased, with a mean depth of about 50 cm in plots with an SI higher than 29 m. The results show that soil physical properties had a major influence on growth rates with soils of a loamy texture resulting in higher rates than clay rich soils. Soil nitrogen and phosphorus availability had significant effects on growth on soils developed on non‐volcanic parent material whilst potassium availability was significant in soils on volcanic parent material. There were strong interactions among the land characteristics of each land unit so that the magnitude of the specific effect of a given variable was highly dependent on the values of the others. Results are discussed in relation to land use planning.
Policy competition in the 2002 French legislative and presidential elections
Authors: LAVER MICHAEL , BENOIT KENNETH , SAUGER NICOLAS
Published: June 2006

Abstract. The French two‐round system of presidential elections forces candidates to choose strategies designed to maximize their votes in two different, potentially conflicting strategic contexts: a first round contest between many candidates, and a second round between (typically) a left‐ and a right‐oriented candidate. Following a constitutional change in 2000, furthermore, presidential elections are synchronized with legislative elections, more tightly linking presidential candidates to the policy platforms of the parties they represent. This article examines the consequences of policy positioning by presidential candidates, measuring, comparing and assessing positioning in the legislative elections and in the first and second presidential election rounds. The measures come from an expert survey taken in 2002, from content analysis of party manifestos and presidential speeches, and from the 2002 French National Election Survey. The findings provide hard empirical confirmation of two commonly perceived propositions: first, that Jospin's first‐round loss resulted from strategic error in moving too close to the policy centre, and second, that Chirac's won an overwhelming second‐round victory because he collected all of the voters from candidates eliminated in the first round.
Larval growth and development in the caddisfly Cheumatopsyche brevilineata under natural thermal regimes
Authors: MOCHIZUKI Shoko , KAYABA Yuichi , TANIDA Kazumi
Published: June 2006

Cheumatopsyche brevilineata (Iwata) is a filter‐feeding caddisfly without distinct or distinguishable cohorts. In a semi‐natural channel, we reared fourth and fifth instar larvae of C. brevilineata in individual cages with hourly recording of water temperature. We calculated the individual growth rate from the wet‐weight gain of each larva, and the development rate from the ratio of larvae that progressed to the next instar or pupal stage during each rearing experiment. We analyzed the linear regressions of growth (increase in size) and development (physiological and morphological progression toward maturity) rates against the statistical parameters of water temperatures during each rearing period, i.e. mean and given percentiles of water temperatures. We presumed that the most appropriate parameter of water temperature to explain larval growth and development would show a peak value of the determination coefficients (r2) in the linear regressions. There were highly significant regressions in the growth rates for fourth and fifth instar larvae and in development rates for fourth instar larvae against every statistical parameter of water temperature, but not in the development rates for fifth instar larvae. For the growth of fourth and fifth instar larvae, we could not specify the most appropriate parameters of water temperatures, because we observed no clear peaks in the determination coefficients. For the development of fourth instar larvae, this parameter could be the 65th percentile value, where the development zero temperature and effective degree‐days were 11.1°C and 56 degree‐days, respectively.
Faunal makeup of wild bees and their flower utilization in a semi‐urbanized area in central Japan
Authors: HISAMATSU Masaki , YAMANE Sôichi
Published: June 2006

The species composition of wild bees and their flower utilization patterns were surveyed from April to November in 1996 in a semi‐urbanized area adjacent to Sugao Marsh, Ibaraki, central Japan. A total of 750 individuals belonging to 43 species in six families were collected. The most dominant family was Halictidae, for which 13 species and 251 individuals were collected. The most dominant species was Colletes patellatus (120 individuals) of the Colletidae. The results at Sugao were compared with those obtained from three other areas of Ibaraki Prefecture, which have similar climatic conditions, yet have different environmental characteristics in terms of human impact. The four sites in Ibaraki can be classified into two groups: the first comprising Sugao and Mito in cultivated and/or human‐dwelling areas, and the second comprising Yamizo and Gozen’yama, in forest areas with more natural elements. The number of species at Sugao was the smallest among the four study sites. On the other hand, the values for species evenness at Sugao were the second‐highest of the four study sites. These findings show that the different characteristics of different bee communities reflect their local environmental conditions, including their floral compositions. The bees visited 36 flower species in 20 families, and 70.7% of all individuals studied visited Compositae flowers. The heavy utilization of composite flowers is possibly because of the existence of a simplified flora consisting of a few dominant composite plant species. Among these plants, Solidago altissima and Lactuca indica made large contributions to supporting autumn bees, especially Colletes patellatus and Colletes perforator, which are solitary and oligolectic on Compositae.
Sexual dimorphism and allometry in two seed beetles (Coleoptera: Bruchidae)
Authors: COLGONI Andrew , VAMOSI Steven M.
Published: June 2006

Male Callosobruchus chinensis (Coleoptera: Bruchidae) have elaborated, pectinate antennae, which are absent from conspecific females and both sexes of a congener, Callosobruchus maculatus. To begin to unravel the mechanisms producing this striking dimorphism, we examined which morphological traits best explain body size variation in bruchid beetles and quantified sexual dimorphism of antenna size through allometric analyses. Using principal component analyses, we found that elytron length and pronotum width were significantly correlated with the first principal component, which was interpreted as explaining variation in body size. Regressions of log‐transformed body size measures on log‐transformed antenna length revealed that males of both species had longer antennae than conspecific females for any given body size, although most of this effect was attributable to higher intercepts, rather than increased allometry, in males. Comparisons among heterospecific males revealed that C. maculatus males have noticeably longer antennae than C. chinensis males at large body sizes. Callosobruchus chinensis males, thus, appear to have increased the receptive area of their antennae by adding to the width of, rather than further elongating, their antennae. Finally, we found evidence for positive allometry between log‐transformed antenna length and log‐transformed antenna width in C. chinensis males. We discuss our results in the context of evidence supporting the presence of an additional, and potentially unique, sex pheromone in C. chinensis females.
Astegopteryx spinocephala (Hemiptera: Aphididae), a new aphid species producing sterile soldiers that guard eggs laid in their gall
Authors: KUROSU Utako , BURANAPANICHPAN Sawai , AOKI Shigeyuki
Published: June 2006

Astegopteryx spinocephala sp. nov., a soldier‐producing aphid species forming banana‐bunch shaped galls on Styrax benzoides in northern Thailand, is described. We found that galls of the species are formed in approximately June and last for almost 1 year, and that the aphid completes its life cycle without migrating to secondary hosts. Many alate sexuparae appeared in March/April, when many sexuals (arostrate males and rostrate females) and eggs were found in live subgalls guarded by soldiers that plugged the ostiole with their sclerotized, spiny heads. Two healthy galls sampled in April contained 2799 and 2659 eggs, respectively. Many live galls were still found in May, and some at the beginning of June. These galls contained both active soldiers and eggs, some of which had already hatched. This indicates that soldiers of A. spinocephala guard eggs until they hatch in at least some galls.
Taxonomic notes on Japanese species of the Nomada furva species group (Hymenoptera: Apidae)
Authors: MITAI Katsushi , TADAUCHI Osamu
Published: June 2006

The furva species group of the genus Nomada in Japan is taxonomically revised and the following three species are recognized: N. okubira Tsuneki, 1973, stat. nov., N. pulawskii Tsuneki, 1973, and N. taicho Tsuneki, 1973. Nomada okubira is raised to species rank, and N. etigonis Tsuneki, 1986, is synonymized under N. okubira. Detailed illustrations of male terminalia are provided for N. okubira and N. taicho. A key to the Japanese species is provided.
Comparison of Cancer Slope Factors Using Different Statistical Approaches‡
Authors: Subramaniam Ravi P. , White Paul , Cogliano V. James
Published: June 2006

The U.S. Environmental Protection Agency's cancer guidelines (USEPA, 2005) present the default approach for the cancer slope factor (denoted here as s*) as the slope of the linear extrapolation to the origin, generally drawn from the 95% lower confidence limit on dose at the lowest prescribed risk level supported by the data. In the past, the cancer slope factor has been calculated as the upper 95% confidence limit on the coefficient (q*1) of the linear term of the multistage model for the extra cancer risk over background. To what extent do the two approaches differ in practice? We addressed this issue by calculating s* and q*1 for 102 data sets for 60 carcinogens using the constrained multistage model to fit the dose‐response data. We also examined how frequently the fitted dose‐response curves departed appreciably from linearity at low dose by comparing q1, the coefficient of the linear term in the multistage polynomial, with a slope factor, sc, derived from a point of departure based on the maximum liklihood estimate of the dose‐response. Another question we addressed is the extent to which s* exceeded sc for various levels of extra risk. For the vast majority of chemicals, the prescribed default EPA methodology for the cancer slope factor provides values very similar to that obtained with the traditionally estimated q*1. At 10% extra risk, q*1/s* is greater than 0.3 for all except one data set; for 82% of the data sets, q*1 is within 0.9 to 1.1 of s*. At the 10% response level, the interquartile range of the ratio, s*/sc, is 1.4 to 2.0.
A Rawlsian Argument Against the Duty of Civility
Authors: Thunder David
Published: June 2006

In this article, I show that the assumptions underpinning John Rawls's so‐called “duty of civility” ought to lead one not to affirm the duty but to reject it. I will begin by setting out in its essentials the content and rationale of the “duty of civility,” which lies at the heart of Rawls's ideal of public reason. Secondly, I will argue that the very premises allegedly underpinning the duty of civility—namely, the values of reciprocity and political autonomy, and the burdens of judgment—in fact rule it out. Thirdly, I will suggest that if my argument against the duty of civility is correct, then one recent attempt to salvage political liberalism and reasonableness from the charge of incoherence fails. Finally, I draw some challenging lessons from our discussion for political liberalism and the liberal tradition as a whole.
Changing patterns of pericardial disease in patients with end‐stage renal disease
Authors: BANERJEE Anindya , DAVENPORT Andrew
Published: June 2006

Pericarditis can occur in patients with chronic renal failure before initiation of dialysis. It is also described in established dialysis patients. Traditionally, the cause of pericarditis in such settings has been attributed to uremia and/or inadequate dialysis and it is consequently thought that intensifying the dialysis process in such patients could improve outcome. We report here 7 cases of acute pericarditis in patients with end‐stage renal disease on renal replacement therapy. Only 3 of the patients gave any history of chest pain, and a pericardial friction rub was only noted in 2. Despite a period of intensive dialysis, none of the patients improved and all required pericardial drainage as the definitive curative procedure. The clinical presentation of acute pericarditis in dialysis patients therefore may be atypical and pericardial drainage should be considered early, as intensive dialysis alone may not lead to resolution.
Physical disability, psychological status, and health‐related quality of life in older hemodialysis patients and age‐matched controls
Authors: ALTINTEPE Lutfullah , LEVENDOGLU Funda , OKUDAN Nilsel , GUNEY Ibrahim , Savas CILLI Ali , UGURLU Hatice , TONBUL Zeki , GOKBEL Hakki , TURK Suleyman
Published: June 2006

We aimed at comparing the elderly adults and normal subjects with regard to their disability, psychological status, and quality of life (QOL). One hundred and twenty‐five dialysis patients and 61 controls were recruited in the study. Depression and anxiety symptoms of the patients were evaluated with the Psychological Symptom Screening List (SCL 90‐R). For evaluating the disability, the Rivermead mobility index (RMI) was utilized. For evaluating the QOL, we used the short form‐36 (SF‐36) scale. The Rivermead mobility index of the patients (9.6±3.4) was found. When compared with controls, dialysis patients had higher levels of disability (p=0.0001). Depression and anxiety symptom scores of these patients were also significantly higher than that of the controls (p<0.05). There was a correlation between the disability and depression symptom scores (r: 0.171, p=0.037). Both physical and mental capacity scores of the dialysis patients were lower than those of the controls (p<0.05 and p<0.05) QOL scores for elderly hemodialysis patients were found to be lower. Their disability was higher, making them dependable on others during their daily lives. Specific exercise programs should be developed for these patients. Even the smallest effort in this regard will result in improvements in physical functioning while bringing them significant benefits.
FIB‐Nanotomography of Particulate Systems—Part II: Particle Recognition and Effect of Boundary Truncation
Authors: Münch Beat , Gasser Philippe , Holzer Lorenz , Flatt Robert
Published: June 2006

The focused ion beam‐nanotomography (FIB‐nt) technique presented in Part I of this article is a novel high‐resolution three‐dimensional (3D) microscopy method that opens new possibilities for the microstructural investigation of fine‐grained granular materials. Specifically, FIB‐nt data volumes allow particle size distributions (PSD) to be determined, and the current paper discusses all the processing steps required to obtain the PSD from 3D data. This includes particle recognition and the subsequent PSD estimation. A refined watershed approach for 3D particle recognition that tolerates concavities on the particle surfaces is presented. Particles at the edge of the 3D data volume are invariably clipped, and because the data volume is of a very limited size, this effect of boundary truncation seriously affects the PSD and needs to be corrected. Therefore, two basic approaches for the stereological correction of the truncation effects are proposed and validated on artificially modeled particle data. Finally, the suggested techniques are applied to real 3D‐particle data from ordinary portland cement and the resulting PSDs compared with data from laser granulometry.
Preparation, Processing, and Characterization of Nano‐Crystalline BaTiO3 Powders and Ceramics Derived from Microemulsion‐Mediated Synthesis
Authors: Pithan C. , Shiratori Y. , Waser R. , Dornseiffer J. , Haegel F.‐H.
Published: June 2006

Monodisperse and nanocrystalline BaTiO3 powders of different stoichiometries were synthesized through the hydrolytic decomposition of mixed metal alkoxide solutions with water‐in‐oil microemulsions as reaction media. The method allows a tailor‐made preparation of powder particles as small as 10 nm in average. Characterization with respect to purity, morphology, and behavior upon annealing was conducted in order to determine appropriate processing conditions for the preparation of pure, dense nanocrystalline ceramics. As a result, ceramics with a mean grain size as small as 35 nm were achieved. Raman spectroscopy revealed for the first time local tetragonality in pure nanocrystalline bulk BaTiO3‐ceramics with such a fine microstructure.
Influence of γ Irradiation on the Mechanical Strength and In Vitro Biodegradation of Porous Hydroxyapatite/Collagen Composite
Authors: Yunoki Shunji , Ikoma Toshiyuki , Monkawa Akira , Ohta Kazushi , Tanaka Junzo , Sotome Shinichi , Shinomiya Kenichi
Published: June 2006

Gamma irradiation treatment (GIT) is the most widely used sterilization method for biomaterials in spite of the potential to degrade polymers. The adverse effects of GIT on the mechanical properties and biological stabilities of porous hydroxyapatite/collagen (HAp/Col) composites were investigated in this study. Those properties of a porous HAp/Col composite stabilized by dehydrothermal treatment (DHT) drastically decreased by GIT in the same manner as conventional pure Col materials. DHT after GIT could partially eliminate the adverse effects, due to the introduction of cross‐linkage among the degraded Col molecules.
Efficient Preparation of Submicrometer α‐Alumina Powders by Calcining Carbon‐Covered Alumina
Authors: Wang Pei , Wang Chunming , Lin Li , Zhu Yuexiang , Xie Youchang
Published: June 2006

A simple method is described to prepare submicrometer α‐alumina by burning carbon supported on the surface of γ‐alumina in oxygen flow at a temperature of 800°C. The burning of carbon generates a large amount of heat and leads to a rapid increase in the local temperature inside the pores of alumina. When the temperature is high enough for the phase transformation, α‐alumina is obtained in a very short time. It was found that, for carbon contents between 6 and 10 wt%, all the γ‐alumina could transform into α‐alumina after burning of carbon in oxygen for a short time, and the transformed particle sizes of α‐alumina were mostly no more than 1 μm.
Refractory α‐SiAlON Containing La2O3
Authors: Shuba Roman , Chen I.‐Wei
Published: June 2006

Refractory Y‐α‐SiAlON with elongated grain morphology was obtained by utilizing La2O3as a densification aid, which resulted in excellent room‐temperature and high‐temperature strength. Room‐temperature strength of 1000 MPa was achieved when La2O3was augmented by adding Y2O3or removing AlN. With only La2O3, a temperature‐independent strength of 800–950 MPa was maintained up to 1100°C, then gradually decreasing by 25% when reaching 1300°C. The R‐curve measurements of fracture toughness showed relatively little dependence on microstructure, consistent with a strong interface that suppresses grain boundary decohesion. Compared with other densification aids such as SiO2, Al2O3, Sc2O3, Y2O3, and Lu2O3, a finer microstructure was obtained by using La2O3. High nitrogen content in the residual La–Si–Al–O–N glass in equilibrium with the nitrogen‐rich α‐SiAlON is suggested to be the cause of these findings.
Analytical Fluid Flow Models for Tape Casting
Authors: Kim Hyun Jun , Krane Matthew John M. , Trumble Kevin P. , Bowman Keith J.
Published: June 2006

The details of fluid flow in tape casting of a Newtonian slurry with a parallel blade are analyzed in terms of the relative magnitudes of the driving forces (wall shear and pressure gradient) and the resulting tape thickness. Prior studies are limited to describe the flow under the blade and within the reservoir. Consideration of the flow after the blade exit indicates that the existence of a zero‐shear plane might have a negative effect on particle alignment in the tape. The more common case of a beveled blade is also analyzed using the one‐dimensional flow model, which is shown to be valid for blade angles up to about 45°. The beveled and parallel blades are compared in terms of productivity, minimum thickness, and potential influence on particle alignment.
The impact of genotype on endocrine complications in thalassaemia major
Authors: Skordis Nicos , Michaelidou Monica , Savva Savvas C. , Ioannou Yiannis , Rousounides Andreas , Kleanthous Marina , Skordos George , Christou Soteroulla
Published: June 2006

Abstract:  Background: The clinical severity in thalassaemia major (TM) depends on the underlying mutations of the β‐globin gene and the degree of iron overload. Objective: The aim of the study was to investigate the impact of genotype on the development of endocrine complications in TM in our center. Subjects and methods: 126 (62 males, 64 females) thalassaemic patients of Greek Cypriot origin with a mean age of 31.2 (17–68) yr were included in the study. All patients, who were on the standard treatment protocol, were subsequently divided into two groups according to their genotype, group A (92): TM with no mitigating factor and group B (34): TM carrying one or more mitigating factors in the β‐ and/or α‐globin genes. Iron overload calculation was based on the amount of red cell consumption and the mean ferritin level over a 12‐year period. Statistical analysis was performed with the SPSS program. Results: Patients in group A, who were consuming larger amounts of blood on transfusions, were more likely to develop hypogonadism (P = 0.001) compared with patients in group B, despite their similar mean ferritin levels. The incidence of other endocrinopathies (short stature, hypothyroidism, and diabetes mellitus) was similar in the two groups. The prevalence of hypothyroidism in splenectomized patients was significantly higher (P = 0.005), whereas the presence of hypogonadism, impaired glucose homeostasis and insulin resistance, although more frequent, was not statistically significant. The clinical severity of TM had no impact on bone mineral density (BMD) in both men and women. BMD was only influenced by gonadal function. Conclusions: This study demonstrates that the underlying genetic defect in TM is a contributing factor for gonadal dysfunction, because the patients with the more severe defects have a greater rate of iron loading through higher red cell consumption.
Identification of HIV‐1 Tat peptides for future therapeutic angiogenesis
Authors: Ismail Mahmoud , Henklein Peter , Huang Xiaohua , Braumann Chris , Rückert Ralph I. , Dubiel Wolfgang
Published: June 2006

Abstract:  Therapeutic angiogenesis represents a novel approach to treat critical limb ischemia when revascularization is no more an option. The clinical use of the vascular endothelial growth factor is questioned, because of its side effects. This study was designed to identify and characterize human immunodeficiency virus type 1 (HIV‐1) Tat‐derived peptides based on their pro‐angiogenic properties. A series of Tat‐derived peptides were synthesized containing mutations in the basic domain. To minimize side effects Tat peptides were selected exerting no effects on the proteasome and on the viability of human umbilical vein endothelial cells (HUVEC). Tatpep5, 15, and 16 increased the endogenous levels of the pro‐angiogenic transcription factors c‐Jun and SP‐1 as well as the production of the plasminogen activator inhibitor‐1 (PAI‐1) by HUVEC. A significant induction of endothelial cell invasion was observed upon treatment of HUVEC with Tat peptides. In addition, selected Tat peptides induced tube formation by HUVEC as visualized and quantified in a Matrigel matrix. Our data demonstrate that the selected Tat peptides fulfill essential criteria for pro‐angiogenic substances. They represent the basis for the development of novel pro‐angiogenic drugs for future therapeutic angiogenesis, which might be applied for treatment of unreconstructible critical limb ischemia.
Metastatic potential of melanomas defined by specific gene expression profiles with no BRAF signature
Authors: Hoek Keith S. , Schlegel Natalie C. , Brafford Patricia , Sucker Antje , Ugurel Selma , Kumar Rajiv , Weber Barbara L. , Nathanson Katherine L. , Phillips David J. , Herlyn Meenhard , Schadendorf Dirk , Dummer Reinhard
Published: June 2006

The molecular biology of metastatic potential in melanoma has been studied many times previously and changes in the expression of many genes have been linked to metastatic behaviour. What is lacking is a systematic characterization of the regulatory relationships between genes whose expression is related to metastatic potential. Such a characterization would produce a molecular taxonomy for melanoma which could feasibly be used to identify epigenetic mechanisms behind changes in metastatic behaviour. To achieve this we carried out three separate DNA microarray analyses on a total of 86 cultures of melanoma. Significantly, multiple testing correction revealed that previous reports describing correlations of gene expression with activating mutations in BRAF or NRAS were incorrect and that no gene expression patterns correlate with the mutation status of these MAPK pathway components. Instead, we identified three different sample cohorts (A, B and C) and found that these cohorts represent melanoma groups of differing metastatic potential. Cohorts A and B were susceptible to transforming growth factor‐β (TGFβ)‐mediated inhibition of proliferation and had low motility. Cohort C was resistant to TGFβ and demonstrated high motility. Meta‐analysis of the data against previous studies linking gene expression and phenotype confirmed that cohorts A and C represent transcription signatures of weakly and strongly metastatic melanomas, respectively. Gene expression co‐regulation suggested that signalling via TGFβ‐type and Wnt/β‐catenin pathways underwent considerable change between cohorts. These results suggest a model for the transition from weakly to strongly metastatic melanomas in which TGFβ‐type signalling upregulates genes expressing vasculogenic/extracellular matrix remodelling factors and Wnt signal inhibitors, coinciding with a downregulation of genes downstream of Wnt signalling.
Evaluation of melanin‐related metabolites as markers of solar ultraviolet‐B radiation
Authors: Wakamatsu Kazumasa , Ito Shosuke
Published: June 2006

Ultraviolet‐B (UVB) radiation due sunlight can result in sunburns and/or suntans. Sunburn occurs only several hours after solar UVB radiation, while a suntan requires several days to several weeks to develop. In the present study, we measured serum and urine levels of melanin‐related metabolites, 5‐S‐cysteinyldopa (5‐S‐CD) and 6‐hydroxy‐5‐methoxyindole‐2‐carboxylic acid (6H5MI2C), in nine subjects exposed to normal sunlight over the course of 12 months. We collected samples in the middle of each month and examined the variation of the markers, the correlation between them, and their correlation with solar UVB radiation. Those markers exhibited a seasonal variation with lower values in the winter and higher values in the summer. Levels of 5‐S‐CD and 6H5MI2C in the serum showed 48% and 54% increases in the summer compared with those in the winter, respectively. Comparison of 5‐S‐CD in the serum and urine showed the highest correlation (r2 = 0.344), followed by the pair of 5‐S‐CD and 6H5MI2C in the serum. Levels of 5‐S‐CD in the serum showed the highest correlation (r2 = 0.729) with the mean solar UVB radiation during the first 10 d of the month, while 6H5MI2C in the serum was highly correlated (r2 = 0.483) with solar UVB radiation during the previous month. Levels of 5‐S‐CD and 6H5MI2C in the serum appear to reflect the degrees of skin injury and pigmentation in the skin, respectively.
Butyrylcholinesterase Activity in Gestational Diabetes: Correlation with Lymphocyte Subpopulations in Peripheral Blood
Authors: Mahmoud Fadia F. , Haines David D. , Abul Habib T. , Omu Alexander E. , Abu‐Donia Mohammad B.
Published: June 2006

Problem  Inefficient clearance of pregnancy‐threatening toxins may contribute to gestational diabetes (GD) and Type II diabetes mellitus (DM) through mechanisms involving immune dysregulation.

Method of Study  Peripheral venous blood from pregnant Kuwaiti women in third trimester, including 15 GD and 17 DM patients, 14 healthy pregnant (HP) and eight non‐pregnant subjects, was analyzed by two‐color flow cytometery for number and percentage representation of T lymphocytes. Buterylcholinesterase (BuChE) activity was measured using buterylthiocholine iodide and spectrophotometry.

Results  Relative to HP, GD patients exhibited higher ratios of activated and memory phenotypes, including CD4+ CD25+ (P < 0.01), CD4+ HLA‐DR (P < 0.05) and CD4+ CD45RO+ (P < 0.05) cells. Serum BuChE activity exhibited positive correlation within the HP cohort with CD4+ CD25+ (P < 0.05), but not in GD and DM cohorts.

Conclusions  Positive correlation between BuChE and a (presumptive) ‘regulatory’ T‐cell phenotype in HP, but not GD or DM may indicate existence of protective detoxification mechanisms against oxidative stress in normal pregnancies.
Activism, Ideology, and Federalism: Judicial Behavior in Constitutional Challenges Before the Rehnquist Court, 1986–2000
Authors: Solberg Rorie Spill , Lindquist Stefanie A.
Published: June 2006

In this study, we evaluate the individual voting behavior of the justices on the Rehnquist Court in cases raising constitutional challenges to federal, state, and local legislation. Using activism, federalism, and ideology as our guiding principles, we evaluate the extent to which the justices' voting behavior is consistent with the conventional wisdom that conservatives are more restraintist and more likely to protect states' rights in conformity with Chief Justice Rehnquist's focus on federalism. Although we find that there is some correlation between judicial ideology and activism, with liberals more activist than conservatives in general, we also find that the conservative wing of the Rehnquist Court is also largely guided by its own ideological reaction to the substantive policy embodied in the laws at issue. Thus, conservative justices as well as liberals are likely to strike down state laws when those laws fail to conform to the ideological preferences. This result underscores the importance of the attitudinal model of judicial behavior as an explanation of voting patterns on the Court, regardless of the justices' rhetoric in favor of judicial restraint or states' rights.