bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of ancient civilization on the northeastern Chinese landscape: palaeoecological evidence from the Western Liaohe River Basin, Inner Mongolia
Authors: Li Y. Y. , Willis K. J. , Zhou L. P. , Cui H. T.
Published: December 2006

The Western Liaohe River Basin in northeastern China is one of the cradles of ancient Chinese civilization. Archaeological records from this region indicate that human occupation began about 8000 years ago and that agriculture and pastoralism were important activities from an early stage. Very little is known, however, about the effects that these activities had upon the landscape. This paper presents the results of a palaeoecological study from a 3.6 m sedimentary sequence in a relict oxbow lake in the Western Liaohe River Basin of southeast Inner Mongolia. The 5400-yr sequence indicates that human activities had a noticeable impact on an apparently open landscape. Buckwheat cultivation began as early as 5400 cal. yr BP with intensification of agricultural activities from approximately 4700 cal. yr BP. Nitrophilous plants such as Solanum and Cerastium, and also Artemisia were growing in the region at certain times, linked with fluctuations in the δ15N record and probably indicative of increased pastoralism and unintentional/ intentional manuring. Burning was probably used for clearance of the steppe vegetation for agriculture with a close relationship apparent between increased influx of microfossil charcoal and the presence of buckwheat. Superimposed upon this record of human impact is also clear indication of three significant intervals of climate change between 2900 and 2600, 1200 and 600 and 600 and 30 cal. yr BP. The latter two are discussed in relation to the ‘Mediaeval Warm Period’ and ‘Little Ice Age’ apparent in sedimentary sequences across the Northern Hemisphere. Discussions are therefore made in terms of the impact that both climate change and ancient Chinese civilizations had upon shaping the present day landscape and vegetation.
Slow disease progression and robust therapy-mediated CD4+ T-cell recovery are associated with efficient thymopoiesis during HIV-1 infection
Authors: Dion Marie-Lise , Bordi Rebeka , Zeidan Joumana , Asaad Robert , Boulassel Mohammed-Rachid , Routy Jean-Pierre , Lederman Micheal M. , Sekaly Rafick-Pierre , Cheynier Remi
Published: December 2006

In chronic HIV infection, most untreated patients lose naive CD4+ and CD8+ T cells, whereas a minority preserve them despite persistent high viremia. Although antiretroviral therapy (ART)–mediated viral suppression generally results in a rise of naive and total CD4+ T cells, certain patients experience very little or no T-cell reconstitution. High peripheral T-cell activation has been linked to poor clinical outcomes, interfering with previous evaluations of thymic function in disease progression and therapy-mediated T-cell recovery. To circumvent this, we used the sj/βTREC ratio, a robust index of thymopoiesis that is independent of peripheral T-cell proliferation, to evaluate the thymic contribution to the preservation and restoration of naive CD4+ T cells. We show that the loss of naive and total CD4+ T cells is the result of or is exacerbated by a sustained thymic defect, whereas efficient thymopoiesis supports naive and total CD4+ T-cell maintenance in slow progressor patients. In ART-treated patients, CD4+ T-cell recovery was associated with the normalization of thymopoiesis, whereas the thymic defect persisted in aviremic patients who failed to recover CD4+ T-cell counts. Overall, we demonstrate that efficient thymopoiesis is key in the natural maintenance and in therapy-mediated recovery of naive and total CD4+ T cells.
Why do patients want to have their blood tested? A qualitative study of patient expectations in general practice
Authors: van Bokhoven Marloes A , Pleunis-van Empel Marjolein CH , Koch Hèlen , Grol Richard PTM , Dinant Geert-Jan , van der Weijden Trudy
Published: December 2006

Background

General practitioners often take their impression of patients' expectations into account in their decision to have blood tests done. It is commonly recommended to involve patients in decision-making during consultations. The study aimed to obtain detailed information on patients' expectations about blood tests.

Methods

Qualitative study among patients in waiting rooms of general practices. Each patient was presented with a short questionnaire about their preferences in terms of diagnostics. Patients who would like blood tests to be done were interviewed.

Results

Fifty-seven (26%) of the 224 respondents wanted blood tests. Twenty-two were interviewed. Patients overestimated the qualities of blood tests. Favourable test results were regarded as proof of good health. Patients regarded blood tests as a useful instrument to screen for serious disorders, and were confirmed in this belief by people in their social environment and by the media. Many patients expected their GP to take an active test ordering approach, though some indicated that they might be convinced if their GP proposed a wait-and-see policy.

Conclusions

GPs' perceptions about patient expectations seem justified: patients appear to have high hopes for testing as a diagnostic tool. They expect diagnostic certainty without mistakes and a proof of good health. The question is whether it would be desirable to remove patients' misconceptions, allowing them to participate in policy decisions on the basis of sound information, or whether it would be better to leave the misconceptions uncontested, in order to retain the 'magic' of additional tests and reassure patients. We expect that clarifying the precise nature of patients' expectations by the GP may be helpful in creating a diagnostic strategy that satisfies both patients and GPs. GPs will have to balance the benefits of reassuring their patients by means of blood tests which may be unnecessary against the benefits of avoiding unnecessary tests. Further research is needed into the effects of different types of patient information and the effects of testing on satisfaction and anxiety.
Utilization of diabetes medication and cost of testing supplies in Saskatchewan, 2001
Authors: Johnson Jeffrey A , Pohar Sheri L , Secnik Kristina , Yurgin Nicole , Hirji Zeenat
Published: December 2006

The purpose of this study was to describe the patterns of antidiabetic medication use and the cost of testing supplies in Canada using information collected by Saskatchewan's Drug Plan (DP) in 2001. The diabetes cohort (n = 41,630) included individuals who met the National Diabetes Surveillance System (NDSS) case definition. An algorithm was then used to identify subjects as having type 1 or type 2 diabetes. Among those identified as having type 2 diabetes (n = 37,625), 38% did not have records for antidiabetic medication in 2001. One-third of patients with type 2 diabetes received monotherapy. Metformin, alone or in combination with other medications, was the most commonly prescribed antidiabetic medication. Just over one-half of the all patients with diabetes had a DP records for diabetes testing supplies. For individuals (n = 4,005) with type 1 diabetes, 79% had a DP record for supplies, with an average annual cost of $472 ± $560. For type 2 diabetes, 50% had records for testing supplies, with an average annual cost of $122 ± $233. Those individuals with type 2 diabetes who used insulin had higher testing supply costs than those on oral antidiabetic medication alone ($359 vs $131; p < 0.001).
Deficiency of functional mannose-binding lectin is not associated with infections in patients with systemic lupus erythematosus
Authors: Bultink Irene EM , Hamann Dörte , Seelen Marc A , Hart Margreet H , Dijkmans Ben AC , Daha Mohamed R , Voskuyl Alexandre E
Published: December 2006

Infection imposes a serious burden on patients with systemic lupus erythematosus (SLE). The increased infection rate in SLE patients has been attributed in part to defects of immune defence. Recently, the lectin pathway of complement activation has also been suggested to play a role in the occurrence of infections in SLE. In previous studies, SLE patients homozygous for mannose-binding lectin (MBL) variant alleles were at an increased risk of acquiring serious infections in comparison with patients who were heterozygous or homozygous for the normal allele. This association suggests a correlation between functional MBL level and occurrence of infections in SLE patients. We therefore investigated the biological activity of MBL and its relationship with the occurrence of infections in patients with SLE. Demographic and clinical data were collected in 103 patients with SLE. Functional MBL serum levels and MBL-induced C4 deposition were measured by enzyme-linked immunosorbent assay using mannan as coat and an MBL- or C4b-specific monoclonal antibody. The complete MBL-dependent pathway activity was determined by using an assay that measures the complete MBL pathway activity in serum, starting with binding of MBL to mannan, and was detected with a specific monoclonal antibody against C5b-9. Charts were systematically reviewed to obtain information on documented infections since diagnosis of SLE. Major infections were defined as infections requiring hospital admission and intravenous administration of antibiotics. In total, 115 infections since diagnosis of lupus, including 42 major infections, were documented in the 103 SLE patients (mean age 41 ± 13 years, mean disease duration 7 ± 4 years). The percentage of SLE patients with severe MBL deficiency was similar to that in 100 healthy controls: 13% versus 14%, respectively. Although deposition of C4 to mannan and MBL pathway activity were reduced in 21% and 43% of 103 SLE patients, respectively, neither functional MBL serum levels nor MBL pathway activity was associated with infections or major infections in regression analyses. In conclusion, SLE patients frequently suffer from infections, but deficiency of functional MBL does not confer additional risk.
Transendothelial migration enhances integrin-dependent human neutrophil chemokinesis
Authors: Gonzalez Anjelica L , El-Bjeirami Wafa , West Jennifer L , McIntire Larry V , Smith C Wayne
Published: December 2006

Transendothelial migration of neutrophils induces phenotypic changes that influence the interactions of neutrophils with extravascular tissue components. To assess the influence of transmigration on neutrophil chemokinetic motility, we used polyethylene glycol hydrogels covalently modified with specific peptide sequences relevant to extracellular matrix proteins. We evaluated fMLP-stimulated human neutrophil motility on peptides Arg-Gly-Asp-Ser (RGDS) and TMKIIPFNRTLIGG (P2), alone and in combination. RGDS is a bioactive sequence found in a number of proteins, and P2 is a membrane-activated complex-1 (Mac-1) ligand located in the γ-chain of the fibrinogen protein. We evaluated, via video microscopy, cell motility by measuring cell displacement from origin and total accumulated distance traveled and then calculated average velocity. Results indicate that although adhesion and shape change were supported by hydrogels containing RGD alone, motility was not. Mac-1-dependent motility was supported on hydrogels containing P2 alone. Motility was enhanced through combined presentation of RGD and P2, engaging Mac-1, αVβ3, and β1 integrins. Naïve neutrophil motility on combined peptide substrates was dependent on Mac-1, and α4β1 while α6β1 contributed to speed and linear movement. Transmigrated neutrophil motility was dependent on αvβ3 and α5β1, and α4β1, α6β1, and Mac-1 contributed to speed and linear motion. Together, the data demonstrate that efficient neutrophil migration, dependent on multi-integrin interaction, is enhanced after transendothelial migration.
Creating Commonplaces for Interpretation: Literary Anthropology and Literacy Education Research
Authors: Sumara Dennis J.
Published: December 2006

This article uses Iser's (1989, 1993) concept of “literary anthropology” to inform methods for textual interpretation that explicitly aim to create relationships among experiences of history, memory, language, and geography. This article presents an interpretive text, which functions as the report of the author's personal engagements with literary fiction and with philosophical, theoretical, and historical writings. In addition, the article provides a theoretical and historical overview of literary anthropology as a research method, with particular attention to how this method is influenced by the hermeneutic philosophic traditions. The article concludes with a discussion of what literary anthropological methods might contribute to literacy education and literacy education research.
Toward a Common Terminology for Talking about Speech and Reading: A Glossary of the “Phon” Words and Some Related Terms
Authors: Scarborough Hollis S. , Brady Susan A.
Published: December 2006

Many phonological terms are found in the contemporary literature on reading, and some inconsistencies and disagreements are apparent in how they are used and understood. To clarify the meanings of these words in current usage, and thereby to facilitate communication in the field of literacy, a thematically organized glossary of these terms and related words is provided.
Constructing Literacy: How Goals, Activity Systems, and Text Shape Classroom Practice
Authors: Ares Nancy M. , Peercy Megan M.
Published: December 2006

Social interaction is important in students' reproduction and transformation of culturally, socially grounded knowledge and skills, as well as their appropriation of the various roles that participation in social groups entails. A focus on social interaction in classrooms provides important perspectives on how teachers' and students' actions and the characteristics of the learning environment shape classroom interactions and outcomes. Using situated learning and cultural-historical activity theories as a framework, our purpose in this case study was to identify and describe features of the classroom context that were important in shaping students' participation in the classroom literacy community. Goals for participation, activity systems, and texts used and produced emerged as profound influences on students' opportunities to participate. Research into how students and teachers construct classroom literacy communities can deepen our understanding of the mutually constitutive relation between contextual elements within classrooms and students' opportunities to learn and to succeed.

Interviewer: What does it mean to do English in Camilla's class?

Students: English is boring. It makes you want to go to sleep. If you know how to write sentences and spell and you know how to read, you know English.

Interviewer: What does it mean to be a reader in this class?

Students: To know what you're reading about. Not just reading the words, but understand. I love to read. (Student focus group #2)
That's My Letter!: What Preschoolers' Name Writing Representations Tell Us about Emergent Literacy Knowledge
Authors: Welsch Jodi G. , Sullivan Amie , Justice Laura M.
Published: December 2006

This study explored the extent to which preschool children's name writing representations reflected their more general emergent literacy knowledge in print and phonological awareness. As part of a preschool literacy screening program, 3,546 4-year-old children were administered a name writing task and additional indices of emergent literacy. Children were placed into four groups based on the level of their name-writing representations. The four groups were compared for performance on alphabet knowledge, concept of word, print knowledge, rhyme awareness, and beginning sound awareness tasks. The four name-writing groups significantly differed from one another on each of these dependent measures. Additionally, a regression analysis showed the linear combination of the five emergent literacy indices to significantly predict level of name writing representation, accounting for 36% of the variance in outcome. Print-related skills (alphabet knowledge, print concepts), in addition to age, accounted for 34% of this variance. While findings suggest that name writing representations can differentiate children in both phonological and print awareness, name writing representations appear to predominantly reflect print-related knowledge.
A “Radical” Approach to Reading Development in Chinese: The Role of Semantic Radicals and Phonetic Radicals
Authors: Ho Connie Suk-Han , Ng Ting-Ting , Ng Wing-Kin
Published: December 2006

Two studies investigating the significance of radical knowledge in Chinese reading development are reported in this paper. Study 1 examined the semantic radical knowledge of 20 Grade 1, 20 Grade 3, and 20 Grade 5 Chinese children in Hong Kong. It was found that various types of semantic radical knowledge, including the position and semantic category of semantic radicals, correlated significantly with Chinese word reading and sentence comprehension. Study 2 examined phonetic radical knowledge with another three groups of 20 Chinese children in Grades 1, 3, and 5 respectively. It was found that various measures of phonetic radical knowledge, including the function and sound value of phonetic radicals, correlated significantly with Chinese word reading. These studies found that, developmentally, the children started acquiring the knowledge of character structure, position, semantic category, and sound value of radicals from about Grade 1. However, they did not understand that the function of semantic radicals is to provide meaning cues in reading until Grade 3. The authors concluded that the radical is an important orthographic processing unit in reading development in Chinese.
Second Grade is Important: Literacy Instruction and Learning of Young Children in a High-Poverty School
Authors: Barone Diane
Published: December 2006

This article is centered on the literacy learning and instruction that 13 children received from kindergarten through second grade. The children were enrolled in a school deemed at risk because of the children's home backgrounds — low SES, minority status, and home language other than English. The purpose of this research was to provide a clearer picture of the day-to-day literacy instruction and learning of children in such a setting to better understand the documented achievement results of children in high-poverty schools. Although there was great variability in the literacy instruction provided to these children from skills-based to more meaning-based instruction, the majority of the children were considered to be at grade level or above at the end of second grade. However, the children displayed variable patterns of literacy development across these grades. During the second grade year meaning-based instruction was made available to students. The second grade teachers were able to build from the skills-based instruction that the students received in kindergarten and first grade and provide a richer understanding of reading and writing. This article shares an overview of the instruction and learning that occurred over the three years and ends with a closer examination of the learning of two children who came to school with a home language of Spanish.
Committed and Reluctant Male Teenage Readers: Beyond Bedtime Stories
Authors: Love Kristina , Hamston Julie
Published: December 2006

In this article we describe the leisure reading practices and attitudes towards reading of two cohorts of teenage boys and their parents from one educated, middle-class school community in Australia. Leisure reading refers to free choice or recreational reading across a range of genres (e.g., fiction/nonfiction) and modes (e.g., print/electronic). First we make explicit the cultural practices in one community that contributed to differential reading formations of boys who are capable readers, and second, we highlight the boys' increasing sense of agency and their selective appropriations of their families' leisure reading dispositions. In so doing, we respond to concerns raised in the research literature regarding the challenges educators and parents face in maintaining teenage boys' engagement in reading a wide range of texts. Drawing on a sociocultural perspective, we compare the patterns of reported leisure reading of teenage boys identified as “able and committed readers” with boys identified as “able and reluctant readers.” Using a model based on Rogoffs (1995) concept of guided participation, we compare the boys' attitudes towards various forms of reading and their parents' reports of family reading practices designed to guide boys into valued forms of leisure reading. We found that despite the similar ways in which both cohorts of boys had been supported as “cultural members” (Rogoff, Goncu, & Mosier, 1993) in developing valued reading practices in the home, the committed readers “took from” (Heath, 1983) their families' reading dispositions in very different ways than did the reluctant readers. A complex portrait of individual choice around reading emerges from our data. Our analytical model of guided participation provides a valuable framework for educators to examine the social formation of other sorts of readers across a range of cultural contexts.
Creating Zones of Possibility for Struggling Readers: A Study of One Fourth Grader's Shifting Roles in Literature Discussions
Authors: Möller Karla J.
Published: December 2006

This is an inductive case study of a European-American fourth-grade girl who struggled with print-based aspects of literacy. The study highlights her multiple levels of competency as she participated over time in a heterogeneous literature discussion group that read and responded to three culturally diverse novels. Data include 27 audio-taped literature discussions, observational field notes, audio-taped interviews and presentations, and written artifacts. Grounded in social constructivist theory, this research documents one reader's non-linear movement from a literacy club outsider to shifting positions as a less-capable member in need of support, a capable peer operating solidly within her zone of proximal development, and a more capable peer working at her actual development level. She supported others' understandings by challenging group members to understand characters' situations, voicing non-stereotypic or antiracist thinking, and connecting self and others to the emotional power of prose. Questioning deficit models of reading and static labels for achievement, this study provides evidence of the contextual nature of displays of literacy competence. Implications focus on the conditions of the learning environment that supported an inclusion model of literature-based reading pedagogy.
Exploring Identities in a Reading Specialization Program
Authors: Assaf Lori Czop
Published: December 2006

This qualitative study used theories of language and learning to explore the identities of one preservice teacher in a reading specialization program. Data sources included archived online course responses, interviews, journals, and an electronic portfolio. Analysis indicates that the participant used multiple discourses as an immigrant, multilanguage learner, and writer/poet to make sense of her learning in the program. These discourses shaped her identities as a teacher and influenced how her peers recognized her. Analyzing online responses over time added to the uniqueness of this study because it allowed the researcher to tap into shared discourse related to course readings and field-based experiences. Negotiating multiple discourses within a learning community influenced the participant's instructional decisions as a student teacher and fashioned her identity with other future teachers. Implications include the significance of exploring multiple identities in relation to a clearly identified program mission, using computer mediated discussions to nurture collaborative reflection, and understanding how a group's common values and commitments can enhance one's teaching identity.
Third through Sixth Graders' Perceptions of High-Stakes Testing
Authors: Triplett Cheri Foster , Barksdale Mary Alice
Published: December 2006

This study examined elementary students' perceptions of high-stakes testing through the use of drawings and writings. On the day after students completed their high-stakes tests in the spring, 225 students were asked to “draw a picture about your recent testing experience.” The same students then responded in writing to the prompt “tell me about your picture.” During data analysis, nine categories were constructed from the themes in students' drawings and written descriptions: Emotions, Easy, Content Areas, Teacher Role, Student Metaphors, Fire, Power/Politics, Adult Language, and Culture of Testing. Each of these categories was supported by drawings and written descriptions. Two additional categories were compelling because of their prevalence in students' drawings: Accoutrements of Testing and Isolation. The researchers examine the prevailing negativity in students' responses and suggest ways to decrease students' overall test anxiety, including making changes in the overall testing culture and changing the role teachers play in test preparation.
What Affects Instructional Choice? Profiles of K-2 Teachers' Use of Reading Instructional Strategies and Methods
Authors: Nichols William D. , Zellner Luana J. , Willson Victor L. , Mergen Sandra , Young Carl A.
Published: December 2006

This study examined kindergarten, first-grade, and second-grade teachers' intended and reported classroom use, as well as perceptions and knowledge of reading strategies and methods, before and after their participation in a 120-hour professional development workshop. A cluster analysis was conducted on the teachers' (N = 33) responses to a reading strategies/methods measure, followed by discriminant analysis on the three predominant types of teachers: (a) those using a structured approach to reading, (b) those using an integrated approach, and (c) those using an eclectic approach—to determine the most important strategies and methods characterizing the different groups. Analysis of variance and qualitative analysis of written evaluations revealed that teachers involved in the professional development experience made significant gains in their use of several reading strategies and methods. Three years after initial training, follow-up interviews with selected teachers from each of the three cluster groups provided an understanding of the long-term effects of the professional development activities. Overall results showed that the teachers' reported use of selected reading instructional strategies and methods was influenced by several factors: (a) the workshop, (b) the district curriculum policy, (c) teacher implementation of targeted reading strategies, (d) teachers' perceptions of their own instructional efficacy, and (e) teachers' perceptions of students' academic needs and performance.
Genetics of Obesity in Humans
Authors: Farooqi I. Sadaf , O’Rahilly Stephen
Published: December 2006

Considerable attention has focused on deciphering the hypothalamic pathways that mediate the behavioral and metabolic effects of leptin. We and others have identified several single gene defects that disrupt the molecules in the leptin-melanocortin pathway causing severe obesity in humans. In this review, we consider these human monogenic obesity syndromes and discuss how far the characterization of these patients has informed our understanding of the physiological role of leptin and the melanocortins in the regulation of human body weight and neuroendocrine function.
The Antiapoptotic Protein BAG3 Is Expressed in Thyroid Carcinomas and Modulates Apoptosis Mediated by Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand
Authors: Chiappetta Gennaro , Ammirante Massimo , Basile Anna , Rosati Alessandra , Festa Michela , Monaco Mario , Vuttariello Emilia , Pasquinelli Rosa , Arra Claudio , Zerilli Monica , Todaro Matilde , Stassi Giorgio , Pezzullo Luciano , Gentilella Antonio , Tosco Alessandra , Pascale Maria , Marzullo Liberato , Belisario Maria Antonietta , Turco Maria Caterina , Leone Arturo
Published: December 2006

Context: We previously showed that BAG3 protein, a member of the BAG (Bcl-2-associated athanogene) co-chaperone family, modulates apoptosis in human leukemias. The expression of BAG3 in other tumor types has not been extensively investigated so far.

Objective: The objective of this study was to analyze BAG3 expression in thyroid neoplastic cells and investigate its influence in cell apoptotic response to TNF-related apoptosis-inducing ligand (TRAIL).

Design, Setting, and Patients: We investigated BAG3 expression in human thyroid carcinoma cell lines, including NPA, and the effect of BAG3-specific small interfering RNA on TRAIL-induced apoptosis in NPA cells. Subsequently, we analyzed BAG3 expression in 30 benign lesions and 56 carcinomas from patients of the Naples Tumor Institute Fondazione Senatore Pascale.

Main Outcome Measures: The main outcome measures were: analysis of BAG3 protein in NPA cells by Western blot and immunocytochemistry; analysis of apoptosis in TRAIL-stimulated NPA cells by flow cytometry; and evaluation of BAG3 expression in specimens from thyroid lesions by immunohistochemistry.

Results: BAG3 was expressed in human thyroid carcinoma cell lines; small interfering RNA-mediated downmodulation of its levels significantly (P < 0.0195) enhanced NPA cell apoptotic response to TRAIL. The protein was not detectable in 19 of 20 specimens of normal thyroid or goiters, whereas 54 of 56 analyzed carcinomas (15 follicular, 28 papillary, and 13 anaplastic) were clearly positive for BAG3 expression.

Conclusions: BAG3 downmodulates the apoptotic response to TRAIL in human neoplastic thyroid cells. The protein is specifically expressed in thyroid carcinomas and not in normal thyroid tissue or goiter.
Cytochrome c oxidase maintains mitochondrial respiration during partial inhibition by nitric oxide
Authors: Palacios-Callender Miriam , Hollis Veronica , Frakich Nanci , Mateo Jesús , Moncada Salvador
Published: December 2006

Nitric oxide (NO), generated endogenously in NO-synthase-transfected cells, increases the reduction of mitochondrial cytochrome c oxidase (CcO) at O2 concentrations ([O2]) above those at which it inhibits cell respiration. Thus, in cells respiring to anoxia, the addition of 2.5 μM L-arginine at 70 μM O2 resulted in reduction of CcO and inhibition of respiration at [O2] of 64.0±0.8 and 24.8±0.8 μM, respectively. This separation of the two effects of NO is related to electron turnover of the enzyme, because the addition of electron donors resulted in inhibition of respiration at progressively higher [O2], and to their eventual convergence. Our results indicate that partial inhibition of CcO by NO leads to an accumulation of reduced cytochrome c and, consequently, to an increase in electron flux through the enzyme population not inhibited by NO. Thus, respiration is maintained without compromising the bioenergetic status of the cell. We suggest that this is a physiological mechanism regulated by the flux of electrons in the mitochondria and by the changing ratio of O2:NO, either during hypoxia or, as a consequence of increases in NO, as a result of cell stress.
A paxillin tyrosine phosphorylation switch regulates the assembly and form of cell-matrix adhesions
Authors: Zaidel-Bar Ronen , Milo Ron , Kam Zvi , Geiger Benjamin
Published: December 2006

Diverse cellular processes are carried out by distinct integrin-mediated adhesions. Cell spreading and migration are driven by focal complexes; robust adhesion to the extracellular matrix by focal adhesions; and matrix remodeling by fibrillar adhesions. The mechanism(s) regulating the spatio-temporal distribution and dynamics of the three types of adhesion are unknown. Here, we combine live-cell imaging, labeling with phosphospecific-antibodies and overexpression of a novel tyrosine phosphomimetic mutant of paxillin, to demonstrate that the modulation of tyrosine phosphorylation of paxillin regulates both the assembly and turnover of adhesion sites. Moreover, phosphorylated paxillin enhanced lamellipodial protrusions, whereas non-phosphorylated paxillin was essential for fibrillar adhesion formation and for fibronectin fibrillogenesis. We further show that focal adhesion kinase preferentially interacted with the tyrosine phosphomimetic paxillin and its recruitment is implicated in high turnover of focal complexes and translocation of focal adhesions. We created a mathematical model that recapitulates the salient features of the measured dynamics, and conclude that tyrosine phosphorylation of the adaptor protein paxillin functions as a major switch, regulating the adhesive phenotype of cells.
DNA methylation promotes Aurora-B-driven phosphorylation of histone H3 in chromosomal subdomains
Authors: Monier Karine , Mouradian Sandrine , Sullivan Kevin F.
Published: December 2006

Confinement of enzymatic reactions to nuclear and chromosomal subdomains regulates functional organization of the nucleus. Aurora-B kinase regulates cell-cycle-dependent phosphorylation of chromosomal substrates through sequential localization to a series of sites on chromosomes and the mitotic spindle. In G2 nuclei, Aurora-B recruitment to heterochromatin restricts histone H3S10 phosphorylation to a domain around centromeres (pericentromeres). However, no intrinsic chromosomal determinants have been implicated in Aurora-B recruitment to interphase pericentromeres. Using cyclin B1 as a cell-cycle marker, we found that the great majority of nuclei exhibiting H3S10 phosphorylated foci were positive for cyclin B1, thus revealing that H3S10 phosphorylation arises at pericentromeres during late S phase and persists in G2. By immunofluorescent in situ hybridization, Aurora-B and H3S10 phosphorylated foci were found more frequently at larger pericentromeres than at smaller ones, revealing a preferential phosphorylation of pericentromeres, exhibiting a high density of methyl cytosines. Disruption of DNA methylation inhibited pericentromeric Aurora-B targeting and H3S10 phosphorylation in G2 nuclei, thus demonstrating the role of DNA methylation in Aurora-B targeting to pericentromeres. These results favour the idea that DNA methylation maintains a local environment essential for regulating the functional properties of sub-chromosomal domains during S-G2 progression.
Basic parametric study of a proton exchange membrane fuel cell
Authors: Kazim A , Lund P
Published: December 2006

In a proton exchange membrane (PEM) fuel cell, there are many parameters that could significantly contribute to its overall performance such as the operating temperature and pressure, membrane conductivity, humidification, and air stoichiometric ratio. In this paper, a basic parametric analysis of a PEM fuel cell at different operating cell temperatures and pressures and air stoichiometric ratios is conducted. At lower cell temperatures and higher cell pressures, better cell performance curves are achieved in terms of cell voltage and power density. Furthermore, the results demonstrated that a higher air stoichiometric ratio would create a greater air utilization rate, which leads to a better fuel cell performance. Nevertheless, the results showed that the magnitude of heat generation in the fuel cell at low cell number is unaffected by the variation in the operating temperature.
Inspection of wood surface waviness defects using the light sectioning method
Authors: Yang D , Jackson M. R. , Parkin R. M.
Published: December 2006

Surface waviness variations are a major type of defect on planed wood products. A number of methods have been investigated for the inspection of waviness defects on wood surfaces. This paper describes a new implementation of the light sectioning method with the latest structured lighting and machine vision techniques for this purpose. As a reference, a laser profilometer is used. The data from the light sectioning method and from the profilometer are highly correlated.
Quality-Based Competition, Profitability, and Variable Costs
Authors: Chambers Chester , Kouvelis Panos , Semple John
Published: December 2006

We consider the impact of variable production costs on competitive behavior in a duopoly where manufacturers compete on quality and price in a two-stage game. In the pricing stage, we make no assumptions regarding these costs—other than that they are positive and increasing in quality—and no assumptions about whether or not the market is covered. In the quality stage, we investigate a broad family of variable cost functions and show how the shape of these functions impacts equilibrium product positions, profits, and market coverage. We find that seemingly slight changes to the cost function’s curvature can produce dramatically different equilibrium outcomes, including the degree of quality differentiation, which competitor is more profitable (the one offering higher or lower quality), and the nature of the market itself (covered or uncovered). Our model helps to predict and explain the diversity of outcomes we see in practice—something the previous literature has been unable to do.
A New Ni-Rich Stevensite From the Ophiolite Complex of Othrys, Central Greece
Authors: Christidis George E. , Mitsis Ioannis
Published: December 2006

The first occurrence of Ni-rich stevensite found in the ophiolite complex of Othrys, Central Greece is described. The stevensite, which develops in cracks in a host serpentinite, formed at the expense of serpentine. Two varieties of stevensite have been described: a Mg-rich, Ni-poorer variety with 0.4–1.2 octahedral Ni atoms per half formula unit (p.h.f.u.) and a Ni-rich variety with >2 Ni atoms p.h.f.u. The layer charge in both varieties is −0.24 p.h.f.u.. Stevensite layers are completely separated when dispersed in dilute polyvinylpyrrolidone (PVP) solutions and begin to convert to talc after heating at 250°C for 90 min. Total conversion to talc is observed at 550°C. Formation of Ni-rich stevensite took place at ambient temperature during supergene processes. The scarcity of Ni-rich stevensite occurrences in nature is attributed to the metastability of smectite and to the analytical procedures used in previous studies. Stevensite is considered a phase containing domains with variable numbers of octahedral vacancies. A new experimental protocol is proposed for the determination of Ni-rich stevensite, based on a combination of XRD after solvation with various organic liquids and subsequent heating at 750°C.
Hydrothermal Synthesis of Mg-Rich and Mg-Ni-Rich Kaolinite
Authors: Bentabol Maria , Cruz Maria Dolores Ruiz , Huertas Francisco Javier , Linares Jose
Published: December 2006

Mg-rich kaolinite and Mg+Ni-rich kaolinite have been synthesized in hydrothermal experiments (200 and 400°C) from poorly crystalline kaolinite and Mg- and Mg+Ni-bearing solutions. Al-rich serpentine and Al-rich chlorite were obtained as sub-products of the reactions. The formation of these phases occurred through a dissolution-precipitation mechanism that led to spherical kaolinite after short reaction times. A morphological evolution towards platy particles and stacks occurred at increasing run times.

Identification of the several phases was carried out using a combination of X-ray diffraction and transmission/analytical electron microscopy. Analytical data indicate that the Mg content in kaolinite increased as a function of the reaction time and temperature, reaching up to 0.46 atoms per half formula unit (a.p.h.f.u.). The measured (Mg+Ni) content reached up to 0.56 a.p.h.f.u.. Both the gradual increase of the b-cell parameter of kaolinite at increasing Mg contents and the presence of new bands on the FTIR spectra of the synthesized kaolinite point to a Mg-for-Al replacement in the octahedral sheet rather than to the presence of serpentine-like layers interstratified in the kaolinite structure.
Adhered Zeolite Preparation on and Within a Muscovite Mica by Hydrothermal Growth
Authors: Johnson Christopher D. , Mallon Anthony J. , Worrall Fred
Published: December 2006

Zeolites and other open framework materials provide a powerful tool for remediation and solidification of a range of cationic wastes (e.g.<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:c="http://cambridge.org/core/content" xmlns:core="http://cambridge.org/core" xmlns:m="http://cambridge.org/core/metadata" xmlns:cup="http://contentservices.cambridge.org" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mnf="http://cambridge.org/core/manifest">NH4+${\rm{NH}}_4^ + $, Pb2+) due to the combined properties of large surface area and cation exchange capacity. However, practical barriers exist to the continued expansion of their use, including handling issues related to the fine particle size, and continued ion exchange following waste adsorption. This study examines the synthesis and characterization of zeolites adhered to a muscovite mica wafer, in order to assess if practical benefit can be derived from the preparation of layered composite materials. The paper demonstrates that increased metal adsorption, as demonstrated by surface chemical composition, can be induced in regions by growth of zeolite on and within the lamellar structure of the matrix. X-ray diffraction studies suggest that a site-specific crystallization mechanism controls the zeolite type and extent of growth, thereby reducing control over the zeolites prepared. However, although increased adsorption has been introduced to the mica, the amount of zeolite added is small (<50 mg per gram of muscovite), and thus any adsorption is very limited.
‘Black’ Soils in the Southern Alps: Clay Mineral Formation and Transformation, X-Ray Amorphous Al Phases and Fe Forms
Authors: Zanelli R. , Egli M. , Mirabella A. , Abdelmoula M. , Plötze M. , Nötzli M.
Published: December 2006

Many soils in southern Switzerland have a black color, contain a large amount of soil organic matter (SOM) and seem to have some andic properties although they did not develop on volcanic parent material. We investigated three typical ‘black’ soils to determine the mechanisms of (clay) mineral formation and transformation. We measured total element pools as well as the dithionite-, pyrophosphate-and oxalate-extractable fractions (Fe, Al, Si). The clay fraction (<2 µm) was analyzed using X-ray diffraction and FTIR spectroscopy. Iron speciation in the solid phase was determined by Mössbauer spectroscopy. With increasing weathering conditions, the plagioclase (albite) content decreases, trioctahedral species in the clay fraction such as biotite, chlorite or trioctahedral vermiculite either decompose or transform into a dioctahedral mineral such as dioctahedral vermiculite or hydroxy interlayered smectite (HIS). Typical weathering products were hydroxy interlayered vermiculite (HIV), HIS, interstratified minerals and kaolinite. The oxidation of Fe(II) into Fe(III) was evident and contributes to the transformation of trioctahedral mineral species into dioctahedral ones. In one soil, a large part of the Fe (up to 41%) was found in the form of Fe oxides. In the surface horizon, the poorly crystalline mineral ferrihydrite was dominant, while in the subsoil goethite prevailed. Maghemite (or maghemite/hematite mixture) was, furthermore, found in distinct concentrations down to a depth of ∼50 cm. The formation of this mineral requires high temperatures which means that a forest fire can influence soil mineralogy down to a considerable depth. The specific climatic conditions with periods of strong humidity alternating with periods of winter droughts, sporadic fire events and the relatively large content of poorly crystalline fractions of Fe and Al contributed to the stabilization of SOM.
Retention, Distribution, and Effects of Intraosseously Administered Ibandronate in the Infarcted Femoral Head
Authors: Aya-ay James , Athavale Sanjay , Morgan-Bagley Stephanie , Bian Haikuo , Bauss Frieder , Kim Harry KW
Published: December 2006

The local distribution, retention, and effects of intraosseous administration of ibandronate in the infarcted femoral heads were studied. Intraosseous administration effectively delivered and distributed ibandronate in the infarcted femoral heads and decreased the femoral head deformity in a large animal model of Legg-Calve-Perthes disease.

Introduction: Bisphosphonate therapy has gained significant attention for the treatment of ischemic osteonecrosis of the femoral head (IOFH) because of its ability to inhibit osteoclastic bone resorption, which has been shown to contribute to the pathogenesis of femoral head deformity. Because IOFH is a localized condition, there is a need to explore the therapeutic potential of local, intraosseous administration of bisphosphonate to prevent the femoral head deformity. The purpose of this study was to investigate the distribution, retention, and effects of intraosseous administration of ibandronate in the infarcted head.

Materials and Methods: IOFH was surgically induced in the right femoral head of 27 piglets. One week later, a second operation was performed to inject 14C-labeled or unlabeled ibandronate directly into the infarcted head. 14C-ibandronate injected heads were assessed after 48 h, 3 weeks, or 7 weeks later to determine the distribution and retention of the drug using autoradiography and liquid scintillation analysis. Femoral heads injected with unlabeled ibandronate were assessed at 7 weeks to determine the degree of deformity using radiography and histomorphometry.

Results: Autoradiography showed that 14C-Ibandronate was widely distributed in three of the four heads examined at 48 h after the injection. Liquid scintillation analysis showed that most of the drug was retained in the injected head, and almost negligible amount of radioactivity was present in the bone and organs elsewhere at 48 h. At 3 and 7 weeks, 50% and 30% of the 14C-drug were found to be retained in the infarcted heads, respectively. Radiographic and histomorphometric assessments showed significantly better preservation of the infarcted heads treated with intraosseous administration of ibandronate compared with saline (p < 0.001).

Conclusions: This study provides for the first time the evidence that local intraosseous administration is an effective route to deliver and distribute ibandronate in the infarcted femoral head to preserve the femoral head structure after ischemic osteonecrosis. In a localized ischemic condition such as IOFH, local administration of bisphosphonate may be preferable to oral or systemic administration because it minimizes the distribution of the drug to the rest of the skeleton and bypasses the need for having a restored blood flow to the infarcted head for the delivery of the drug.
Consumer Racism and Its Effects on Domestic Cross-Ethnic Product Purchase: An Empirical Test in the United States, Canada, and France
Authors: Ouellet Jean-François
Published: December 2006

This study provides empirical evidence of the effects of consumer racism on domestic cross-ethnic product purchase in three countries. The model predicts that consumer racism will affect ethnic majorities’ judgments of and willingness to buy products from each country's dominant ethnic minority. After a consumer racism measurement instrument is developed and validated, experiments and survey results show that varying levels of consumer racism affect consumer judgments of and willingness to buy domestic products that are perceived as being made by ethnic minorities in the three countries in which the tests took place. Moreover, the results indicate that minority-owned business performance is significantly and negatively affected in areas in which consumer racism is more prevalent. Moderators of consumer racism effects are the perceived level of interaction between consumers and the minority-owned company, a certain product-ethnicity image, and consumers’ perceived importance of the outcome associated with consuming minority-owned companies’ products and/or services.