bluuebunny/crossref_metadata_2025 huggingface dataset:
Independent and combined influence of homeownership, occupation, education, income, and community poverty on physical health in persons with arthritis
Authors: Callahan Leigh F. , Martin Kathryn Remmes , Shreffler Jack , Kumar Deepak , Schoster Britta , Kaufman Jay S. , Schwartz Todd A.
Published: January 2011

Objective

To examine the independent and combined influence of individual‐ and community‐level socioeconomic status (SES) measures on physical health status outcomes in people with self‐reported arthritis.

Methods

From 2004–2005, 968 participants completed a telephone survey assessing health status, chronic conditions, community characteristics, and sociodemographic variables. Individual‐level SES measures used included homeownership, occupation (professional or not), educational attainment (less than high school, high school degree, and more than high school), and income (<$15,000, $15,000–$45,000, and >$45,000). Community poverty (2000 US Census block group percentage of individuals living below the poverty line [low, medium, and high]) was used as a community‐level SES measure. Outcomes were physical functioning (Medical Outcomes Study Short Form 12 version 2 physical component summary [PCS]), functional disability (Health Assessment Questionnaire [HAQ]), and the Centers for Disease Control and Prevention (CDC) Health‐Related Quality of Life (HRQOL) Healthy Days physical and limited activity days, and were analyzed via multivariable regressions.

Results

When entered separately, all individual‐level SES variables were significantly (P< 0.01) associated with poorer PCS, HAQ, and CDC HRQOL scores. A higher magnitude of effect was seen for household income, specifically <$15,000 per year in final models with all 4 individual SES measures and community poverty. The magnitude of effect for education is reduced and marginally significant for the PCS and number of physically unhealthy days. No effects were seen for occupation, homeownership, and community poverty.

Conclusion

Findings confirm that after adjusting for important covariates, lower individual‐ and community‐level SES measures are associated with poorer physical health outcomes, while household income is the strongest predictor (as measured by both significance and effect) of poorer health status in final models. Studies not having participant‐reported income available should make use of other SES measures, as they do independently predict physical health.
Substantial variation in qPCR measured mean blood telomere lengths in young men from eleven European countries
Authors: Eisenberg Dan T.A. , Salpea Klelia D. , Kuzawa Christopher W. , Hayes M. Geoffrey , Humphries Steve E. ,   on Behalf of the European Atherosclerosis Research Study II Group
Published: January 2011

Objectives: Telomeres, repetitive DNA sequences found at the ends of chromosomes, shorten with age in proliferating human tissues and are implicated in senescence. Previous studies suggest that shorter telomeres impair immune and cardiovascular function and result in increased mortality. Although few, prior studies have documented ethnic/population differences in human telomere lengths. The nature and cause(s) of these population differences remain poorly understood.

Methods: Here, we extend the work of Salpea et al. (2008) by reporting variation in mean blood telomere lengths (BTL) from 765 individuals from 14 study centers across 11 European countries. Subjects are male students (ages 18–28), half of whom had fathers with myocardial infarction before 55 and the remainder age‐matched controls.

Results: Controlling for age and case–control status, telomere lengths averaged 10.20 kilobases (interpolated from qPCR measures) across study centers and ranged from 5.10 kilobases in Naples, Italy to 18.64 kilobases in Ghent, Belgium—a greater than threefold difference across populations. These population level differences in BTLs were neither explained by national level measures of population genetic structure nor by national level ecological analysis of indices of infection/economic status.

Conclusions: These findings suggest considerable population variation in BTL in Europe that is not obviously a result of broad measures of population structure or infection/economic exposure measured in early life or in adulthood. Studying telomere dynamics in a wider variety of populations, and with greater attention to lifecycle dynamics, will be important to help elucidate the causes and possible consequences of human population variation in telomere length. Am. J. Hum. Biol., 2011. © 2011 Wiley‐Liss, Inc
YKL‐40 and MMP‐9 as serum markers for patients with primary central nervous system lymphoma
Authors: Hottinger Andreas F. , Iwamoto Fabio M. , Karimi Sasan , Riedel Elyn , Dantis Jocelynn , Park Joseph , Panageas Katherine S. , Lassman Andrew B. , Abrey Lauren E. , Fleisher Martin , Holland Eric C. , DeAngelis Lisa M. , Hormigo Adília
Published: January 2011

Objective:

To evaluate YKL‐40 and MMP‐9 proteins as tumor biomarkers in serum samples from patients with primary central nervous system lymphoma (PCNSL).

Methods:

In this prospective longitudinal study, serum samples from consecutive patients with histologically confirmed PCNSL were collected concurrently with magnetic resonance imaging (MRI) scans at multiple time points and were analyzed for levels of YKL‐40 and MMP‐9 by enzyme‐linked immunosorbent assay. Marker levels were correlated to disease status and survival.

Results:

Forty‐five patients with PCNSL were accrued. Median follow‐up for survivors was 25 months, and 21 (47%) died during the study. A total of 230 serum samples were collected, and 93% had corresponding MRI scans. PCNSL patients without evidence of radiographic disease (29 patients, 131 samples) had significantly lower levels of serum YKL‐40 and MMP‐9 than patients with active tumor (n = 34 patients, 84 samples; p = 0.03 and 0.01, respectively). There was a significant inverse correlation between survival and doubling of the YKL‐40 level (hazard ratio, 1.7; p = 0.01).

Interpretation:

In patients with PCNSL, serum levels of YKL‐40 and MMP‐9 are associated with radiographic disease status. Longitudinal increase in serum levels of YKL‐40, but not MMP‐9, predicts survival in patients with PCNSL. ANN NEUROL 2011
Necessity of acceleration‐induced nonlocality
Authors: Mashhoon B.
Published: January 2011

The purpose of this paper is to explain clearly why nonlocality must be an essential part of the theory of relativity. In the standard local version of this theory, Lorentz invariance is extended to accelerated observers by assuming that they are pointwise inertial. This locality postulate is exact when dealing with phenomena involving classical point particles and rays of radiation, but breaks down for electromagnetic fields, as field properties in general cannot be measured instantaneously. The problem is corrected in nonlocal relativity by supplementing the locality postulate with a certain average over the past world line of the observer.
Nanoparticles in Biological Systems
Authors: Stark Wendelin J.
Published: January 2011

Understanding the behavior of nanoparticles in biological systems opens up new directions for medical treatments and is essential for the development of safe nanotechnology. This Review discusses molecules and nanoparticles when in contact with cells or whole organisms, with a focus on inorganic materials. The interaction of particles with biology unravels a series of new mechanisms not found for molecules: altered biodistribution, chemically reactive interfaces, and the combination of solid‐state properties and mobility. Externally guided movement of medicaments by using functional nanomagnets brings mechanics into drug design. In subsequent sections, the role of inertness and bioaccumulation is discussed in regard to the long‐term safety of nanoparticles.
Selective oxidation of olefins and aromatic alcohols with tert‐butylhydroperoxide catalyzed by polymer‐anchored transition‐metal complexes
Authors: Islam S. M. , Singha Roy Anupam , Mondal Paramita , Mondal Sanchita , Mubarak Manir , Hossain Dildar , Sarkar Saikat
Published: January 2011

Three polymer‐anchored metal complexes (Co, Cu, and Pd) were synthesized and characterized. The catalytic performance of these complexes was tested for the oxidation of olefins and aromatic alcohols. These complexes showed excellent catalytic activity and high selectivity. These complexes selectively gave epoxides and aldehydes from olefins and alcohols, respectively. Individually, the effect of various solvents, oxidants, substrate oxidant molar ratios, temperatures, and catalyst amounts for the oxidation of cyclohexene and benzyl alcohol were studied. Under optimized reaction conditions, 96, 81, and 71% conversions of cyclohexene and 86, 79, and 73% conversions of benzyl alcohol were obtained with Co(II), Cu(II), and Pd(II) catalysts, respectively. The catalytic results reveal that these complexes could be recycled more than five times without much loss in activity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Studies on novel semi‐2‐IPNs from polyetherimide and citraconimide
Authors: Gupta Preshi , Alam Sarfaraz
Published: January 2011

A series of novel semi‐2‐interpenetrating polymeric networks (semi‐2‐IPNs) were prepared through blending in solution using two different polyimides, biscitraconamic acid as a precursor of biscitraconimide (MBMI) with various proportions of polyetherimide (PEI) to achieve optimum properties. Biscitraconamic acid was prepared by reacting citraconic anhydride (CA), 3,3',4,4'‐benzophenone tetracarboxylic dianhydride (BTDA) and bis(3‐aminopropyl)phenyl phosphine (BAPPP) and it was characterized by differential scanning calorimetry (DSC), FTIR, and 1H‐NMR spectroscopy. Both biscitraconamic acid and PEI were blended in N,N‐dimethylacetamide (DMAc) solution, casted and thermally cured up to 300°C to give semi‐2‐IPNs. The MBMI/PEI semi‐IPN systems were characterized by UV‐Vis spectroscopy, FTIR spectroscopy and thermal techniques. The phase morphology, isothermal aging, and water uptake of semi‐IPN systems have also been studied. The morphological studies on phase distribution were investigated by scanning electron microscopy (SEM). Thermal performance of MBMI/PEI semi‐IPN systems were evaluated by DSC and thermo gravimetric analysis (TGA). All the compositions of semi‐IPN polyimide system were stable up to 400°C and their thermal stability increased with increase in the content of PEI. Isothermal aging studies done at 300°C for various time periods showed good thermo‐oxidative stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and characterization of polybutadiene/allylisobutyl polyhedral oligomeric silsesquioxane nanocomposites by anionic polymerization
Authors: Liao Mingyi , Zhang Xiaojuan , Fan Cheng , Wang Liying , Jin Meihua
Published: January 2011

Polybutadiene (PB)/Allylisobutyl Polyhedral Oligomeric Silsesquioxane (A‐POSS) nanocomposites have been prepared by using A‐POSS and butadiene (Bd) as comonomers, n‐BuLi as initiator, cyclohexane as solvent, ethyltetrahydrofurfuryl ether as structure modifier through the anionic polymerization technique. The reaction conditions, the kind and content of the modifier and POSS, etc. affecting the copolymerization process and the microstructure of the nanocomposites were also investigated. The results showed that POSS incorporation obviously decreased the rate of polymerization and the molecular weight of the copolymers, increased polydispersity index of the copolymers. The reaction conditions (the reaction time and reaction temperature) had little effect on copolymerization. However, the addition of the modifier could increase the rate of polymerization significantly. In particular, the POSS incorporation resulted in dramatically increasing the content of 1,2‐units in PB. POSS and the modifier had the excellent cooperative effect modifying the microstructure of the PB. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Investigations of chromatic transformations of polydiacetylene with aromatic compounds
Authors: Scoville S. P. , Shirley W. M.
Published: January 2011

Thermochromic changes of 10,12‐pentacosadiynoic acid (PCDA) were investigated in combination with four aromatic compounds, benzene, furan, thiophene, and cyclopentadiene, with subsequent exposure to UV radiation. Using Raman spectroscopy and solid‐state Fluorometry, no differences were observed between benzene, furan, or thiophene from the PCDA itself, with respect to the blue to red color change, which took place from 80°C to 100°C. However, the addition of cyclopentadiene exhibited the color change at a significantly higher temperature, ranging from 180°C to 200°C. Lack of new products formed during the initial mixing period was ruled out by analysis using solid‐state NMR MAS and differential scanning calorimetry (DSC), with only monomer peaks at 69.61°C for the PCDA and 72.37°C for PCDA in combination with cyclopentadiene, as recorded by the DSC. It is believed that a chemical bond between PCDA and cyclopentadiene is formed after polymerization from catalysis by the UV radiation. Solid‐state NMR MAS revealed a chemical shift peak of 131.55 ppm for the PCDA and a much larger peak at 130.84 ppm for the PCDA and cyclopentadiene. The DSC exhibited melting point peaks at 193.26°C and 194.88°C for PCDA and PCDA with cyclopentadiene, respectively. Because the color change involves CC bond rotation of side groups, stressing π‐bond overlap, the cyclopentadiene bond is thought to prevent rotation by steric hindrance until a higher temperature or melting occurs at the DSC stated temperature of 194.88°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Regioselective and green synthesis of nitro aromatic compounds using polymer‐supported sodium nitrite/KHSO4
Authors: Karimi Zarchi Mohammad Ali , Rahmani Fahimeh
Published: January 2011

Polymer supported reagents have become the subject of considerable and increasing interest as insoluble materials in the organic synthesis. Use of polymeric reagents simplifies routine nitration of aromatic compounds because it eliminates traditional purification. In this article, the use of readily available cross‐linked poly(4‐vinylpyridine) supported sodium nitrite, [P4‐Me] NO2, as an efficient polymeric nitrating agent in the presence of KHSO4 is described. A good range of available aromatic compounds were also subjected to nitration in the presence of [P4‐Me] NO2/KHSO4. This reagent is regioselective and chemoselective nitrating polymeric reagent for activated aromatic rings. In this procedure, the work‐up is easy, and the spent polymeric reagent is easily regenerated and reused. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation, structural, and electrical studies of polyaniline/ZnFe2O4 nanocomposites
Authors: Prasanna Gunderi Dhananjaya , Jayanna Halepoojar Siddalingappa , Prasad Vishnu
Published: January 2011

Polyaniline/ZnFe2O4 nanocomposites were synthesized by a simple and inexpensive one‐step in situ polymerization method in the presence of ZnFe2O4 nanoparticles. The structural, morphological, and electrical properties of the samples were characterized by wide angle X‐ray diffraction (WAXD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). WAXD and SEM revealed the formation of polyaniline/ZnFe2O4 nanocomposites. Infrared spectroscopy indicated that there was some interaction between the ZnFe2O4 nanoparticles and polyaniline. The dc electrical conductivity measurements were carried in the temperature range of 80 to 300 K. With increase in the doping concentration of ZnFe2O4, the conductivity of the nanocomposites found to be decreasing from 5.15 to 0.92 Scm−1 and the temperature dependent resistivity follows ln ρ(T) ∼ T−1/2 behavior. The nanocomposites (80 wt % of ZnFe2O4) show a more negative magnetoresistance compared with that of pure polyaniline (PANI). These results suggest that the interaction between the polymer matrix PANI and zinc nanoparticles take place in these nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Properties of bacterial cellulose produced in grape medium by native isolate Gluconacetobacter sp
Authors: Rani M. Usha , Udayasankar K. , Appaiah K. A. Anu
Published: January 2011

During the production of grape wine, the occurrence of thick leathery pellicle at the air‐liquid interface was found as a contaminant. The pellicle produced was investigated with a view to use as biodegradable polymer. The bacterium that is responsible for the pellicle production was isolated, characterized and identified as Gluconacetobacter sp. Pellicle was produced in pasteurized grape extract as well as in HS medium by the isolated organism in static conditions. The purified film was subjected for Fourier transform infrared spectroscopy and C13 solid NMR spectroscopy analysis, which confirmed the pellicle to be a cellulosic material. Scanning Electron Micrograph showed ultra fine network structure along with cells. The films were tested for its physicomechanical characters, barrier and thermal properties. The films of 25‐μ thickness showed very high tensile strength (41.158 MPa) and elongation of 0.987 mm. The thermal properties of the films were characterized by Differential scanning calorimetry and Thermo gravimetric analysis. The melt peak temperature was found to be 111.65°C. The percentage of weight loss was found to be 20% at 327.86°C. Barrier properties (oxygen transmission rate and water vapor transmission rate), indicated a high oxygen barrier but low water barrier. This is the first report on the barrier properties of bacterial cellulose from Gluconacetobacter sp. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Topographical and chemical characterization of polymer surfaces modified by physical and chemical processes
Authors: Barish Jeffrey A. , Goddard Julie M.
Published: January 2011

Nanoscale changes to the surface of polymeric materials enables changes in materials' adhesion, wettability, printability, chemical functionality, and bioactivity, while maintaining desirable bulk properties. Polymer surface modification is therefore used in applications such as antimicrobial or non‐fouling materials, biosensors, and active packaging. The range of available modification and analytical techniques used across laboratories prevents accurate comparison of techniques in terms of their effects on surface chemistry and topography. It was therefore our goal to evaluate the effects of four surface modification techniques (chromic acid, piranha solution, ultraviolet irradiation, and oxygen plasma) on polyethylene films. Changes in surface chemistry and topography were quantified using attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), contact angle measurement, and direct measurement of available surface carboxylic acids. Roughness increased in the order: piranha (57.7 nm); oxygen plasma (76.3 nm); UV irradiation (76.4 nm); chromic acid (120 nm). Hydrophobicity decreased in the order: piranha (77.20), chromic acid (73.50), oxygen plasma (61.70), UV irradiation (58.70). Functionalization (by IR absorbance intensity between 1680–1780 cm−1) increased in the order: oxygen plasma (0.06), piranha (0.09), chromic acid (0.34), UV irradiation (0.50). By analyzing these methods using consistent analytical techniques, side‐by‐side comparisons have been accurately made. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of the extensional flow on the properties of oriented nanocomposite films for twist wrapping
Authors: Dintcheva Nadka Tzankova , Marino Rosamaria , La Mantia Francesco Paolo
Published: January 2011

In this study, we examined the mechanical behavior of nanocomposite films based on polyethylene (PE) and pristine PE films. The films were prepared by film blowing and were then cold‐drawn at low temperature. The experimental results show that cold drawing significantly enhanced the orientation; with increasing draw ratio (DR), the elastic modulus and tensile strength of the PE films strongly increased, particularly in the presence of the organoclay. To obtain polymeric films suitable for twist wrapping, the films must be sufficiently stiff so that no shrinkage or elastic recovery occur during or after twisting. The elongation at break and the yield strain sharply decreased with orientation, mainly in films upon drawing. According to the mechanical behavior, the twist angle increased with increasing DR and, particularly, with the addition of nanoclay, probably because of the applied DR, which reduced the nanoparticle size and, as a consequence, hindered the applied torsional elastic recovery. Therefore, the nanocomposite film with a higher DR was particularly suitable for twist‐wrapping applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Varus–valgus alignment: Reduced risk of subsequent cartilage loss in the less loaded compartment
Authors: Moisio Kirsten , Chang Alison , Eckstein Felix , Chmiel Joan S. , Wirth Wolfgang , Almagor Orit , Prasad Pottumarthi , Cahue September , Kothari Ami , Sharma Leena
Published: January 2011

Objective

Varus–valgus alignment has been linked to subsequent progression of osteoarthritis (OA) within the mechanically stressed (medial for varus, lateral for valgus) tibiofemoral compartment. Cartilage data from the off‐loaded compartment are sparse. The purpose of this study was to examine our hypotheses that neutral and valgus (versus varus) knees each have reduced odds of cartilage loss in the medial subregions and that neutral and varus (versus valgus) knees each have reduced odds of cartilage loss in the lateral subregions.

Methods

Patients with knee OA underwent knee magnetic resonance imaging at baseline and 2 years. The mean cartilage thickness was quantified within 5 tibial and 3 femoral subregions. We used logistic regression with generalized estimating equations to analyze the relationship between baseline alignment and subregional cartilage loss at 2 years, adjusting for age, sex, body mass index, and disease severity.

Results

A reduced risk of cartilage loss in the medial subregions was associated with neutral (versus varus) alignment (external tibial, central femoral, external femoral) and with valgus (versus varus) alignment (central tibial, external tibial, central femoral, external femoral). A reduced risk of cartilage loss in the lateral subregions was associated with neutral (versus valgus) alignment (central tibial, internal tibial, posterior tibial) and with varus (versus valgus) alignment (central tibial, external tibial, posterior tibial, external femoral).

Conclusion

Neutral and valgus alignment were each associated with a reduction in the risk of subsequent cartilage loss in certain medial subregions and neutral and varus alignment with a reduction in the risk of cartilage loss in certain lateral subregions. These results support load redistribution as an in vivo mechanism of the long‐term alignment effects on cartilage loss in knee OA.
Activation‐induced deaminase–deficient MRL/lpr mice secrete high levels of protective antibodies against lupus nephritis
Authors: Jiang Chuancang , Zhao Ming‐Lang , Scearce Richard M. , Diaz Marilyn
Published: January 2011

Objective

We previously generated MRL/lpr mice deficient in activation‐induced deaminase (AID) that lack isotype switching and immunoglobulin hypermutation. These mice have high levels of unmutated (germline) autoreactive IgM, yet they experienced an increase in survival and an improvement in lupus nephritis that exceeded that of MRL/lpr mice lacking IgG. The purpose of the present study was to test the hypothesis that high levels of germline autoreactive IgM in these mice confer protection against lupus nephritis.

Methods

Autoreactive IgM antibodies of various specificities, including antibodies against double‐stranded DNA (dsDNA), from AID‐deficient MRL/lpr mice were given to asymptomatic MRL/lpr mice, and the levels of cytokines, proteinuria, immune complex deposition in the kidneys, and glomerulonephritis were examined. Novel AID‐deficient MRL/lpr mice that lack any antibodies were generated for comparison to AID‐deficient MRL/lpr mice that secrete only IgM.

Results

Treatment with IgM anti‐dsDNA resulted in a dramatic improvement in lupus nephritis. Other autoreactive IgM antibodies, such as antiphospholipid and anti‐Sm, did not alter the pathologic changes. Secretion of proinflammatory cytokines by macrophages and the levels of inflammatory cells and apoptotic debris in the kidneys were lower in mice receiving IgM anti‐dsDNA. Protective IgM derived from AID‐deficient MRL/lpr mice displayed a distinct B cell repertoire, with a bias toward members of the VH7183 family.

Conclusion

IgM anti‐dsDNA protected MRL/lpr mice from lupus nephritis, likely by stopping the inflammatory cascade leading to kidney damage. A distinct repertoire of VH usage in IgM anti‐dsDNA hybridomas from AID‐deficient mice suggests that there is enrichment of a dedicated B cell population that secretes unmutated protective IgM in these mice.
B cell reconstitution and T helper cell balance after rituximab treatment of active primary Sjögren's syndrome: A double‐blind, placebo‐controlled study
Authors: Abdulahad W. H. , Meijer J. M. , Kroese F. G. M. , Meiners P. M. , Vissink A. , Spijkervet F. K. L. , Kallenberg C. G. M. , Bootsma H.
Published: January 2011

Objective

To assess the phenotype of reconstituting B cells after B cell depletion, and to assess the effect of reconstitution on the balance of Treg cells and effector T cells in patients with active primary Sjögren's syndrome (SS).

Methods

Twenty‐eight patients with primary SS were treated on days 1 and 15 with either rituximab (n = 19) or placebo (n = 9). The frequencies and absolute numbers of circulating B cell subsets, Treg cells, and effector T cells were examined in fresh blood samples by 4‐color flow cytometry at baseline and 5, 12, 24, 36, and 48 weeks after the first infusion. The results in rituximab‐treated patients were compared with those in patients receiving placebo and with those in age‐ and sex‐matched healthy controls (n = 10).

Results

At baseline, patients with primary SS displayed several abnormalities in B cell homeostasis, including a significant reduction of CD27+ B cells and expansion of CD27– B cells, compared with healthy controls. At week 48 after rituximab treatment, the majority of emerging B cells exhibited a phenotype of transitional B cells. Although recovery of CD27+ memory B cells was delayed after rituximab treatment, a significant increase in Ig class–switched memory B cells within the memory pool was observed. In addition, percentages and absolute numbers of Treg cells and effector T cells, as well as ratios of effector T cells to Treg cells, did not change significantly after rituximab treatment.

Conclusion

The characteristics of reconstituted B cells in patients with primary SS following depletion by rituximab treatment showed dominance of transitional B cells during the early recovery phase, which corresponds to bone marrow–derived repopulation. The depletion of B cells did not influence the balance of peripheral Treg cells and effector T cells.
Pharmacodynamic analysis of stress erythropoiesis: change in erythropoietin receptor pool size following double phlebotomies in sheep
Authors: Saleh Mohammad I. , Widness John A. , Veng‐Pedersen Peter
Published: January 2011

A feedback receptor regulation model was incorporated into a pharmacodynamic model to describe the stimulation of hemoglobin (Hb) production by endogenous erythropoietin (EPO). The model considers the dynamic changes that take place in the EPO receptor (EPOR) pool under phlebotomy‐induced anemia. Using a125I‐rhEPO tracer the EPO clearance changes are evaluated longitudinally prior to and following phlebotomy‐induced anemia indirectly to evaluate changes in the EPOR pool size, which has been shown to be linearly related to the clearance. The proposed model simultaneously captures the general behavior of temporal changes in Hb relative to EPO plasma clearance in five lambs (r= 0.95), while accounting for the confounding variables of phlebotomy and changes in the blood volume in the growing animals. The results indicate that under anemia the EPOR pool size is up‐regulated by a factor of nearly two over baseline and that the lowest and highest EPOR pool sizes differ by a factor of approximately four. The kinetic model developed and the data‐driven mechanism proposed serves as a starting point for developing an optimal EPO dosing algorithm for the treatment of neonatal anemia. Copyright © 2011 John Wiley & Sons, Ltd.
Everyday antiracism in interpersonal contexts: Constraining and facilitating factors for ‘speaking up’ against racism
Authors: Mitchell Margaret , Every Danielle , Ranzijn Rob
Published: January 2011

Everyday conversations among non‐Indigenous Australians are a significant site in which racism towards Indigenous Australians is reproduced and maintained. This study explores the possibilities of everyday antiracism by asking how people negotiate racist discourses in interpersonal contexts. Twelve first year psychology students (10 female, 2 male, aged 18–50) who had completed a compulsory Indigenous studies course were recruited as participants. Semi‐structured interviews were thematically analysed for the constraints and facilitators for responding to racism in everyday contexts. As constraints against speaking up, participants offered ‘social expectations to fit in’, ‘fear of provoking aggression and conflict’, assessments of ‘the type of relationship’, whether they ‘could make a difference’ and the ‘type of racism’. As a facilitator for speaking up, participants reported they were confident in challenging erroneous statements when they felt well informed and authoritative about the facts. The research suggests that everyday antiracism requires a preparedness to deal with possible discomfort and ‘bad feeling’ which participants reported avoiding. The paper concludes with suggestions for stimulating critical thinking and intergroup dialogue in relation to everyday antiracism. Copyright © 2011 John Wiley & Sons, Ltd.
A G‐Quadruplex Aptamer Inhibits the Phosphatase Activity of Oncogenic Protein Shp2 in vitro
Authors: Hu Jia , Wu Jie , Li Cong , Zhu Ling , Zhang Wei Yun , Kong Guiping , Lu Zhongxian , Yang Chaoyong James
Published: January 2011

Shp2 is a member of the protein tyrosine phosphatase (PTP) family, which regulates a variety of cellular processes including cell growth, differentiation, mitotic cycle, and oncogenic transformation. Using a recombinant Shp2‐GST protein as the target and GST as a counter target, we have identified two classes of single‐stranded DNA aptamers that selectively bind to Shp2 with a Kd in the nanomolar range. Structural studies of the most abundant sequence in the enriched library, HJ24, revealed a parallel G‐quadruplex as the core binding domain. Furthermore, this aptamer was found to be an effective inhibitor of Shp2 phosphatase, an effect which was readily reversed by using the cDNA of HJ24. In view of these characteristics, this aptamer has the potential to be used for further development of Shp2 assays and therapeutics for the treatment of Shp2‐dependent cancers and other diseases.
Bacterial Inclusion Bodies of Alzheimer's Disease β‐Amyloid Peptides Can Be Employed To Study Native‐Like Aggregation Intermediate States
Authors: Dasari Muralidhar , Espargaro Alba , Sabate Raimon , Lopez del Amo Juan Miguel , Fink Uwe , Grelle Gerlinde , Bieschke Jan , Ventura Salvador , Reif Bernd
Published: January 2011

The structures of oligomeric intermediate states in the aggregation process of Alzheimer's disease β‐amyloid peptides have been the subject of debate for many years. Bacterial inclusion bodies contain large amounts of small heat shock proteins (sHSPs), which are highly homologous to those found in the plaques of the brains of Alzheimer's disease patients. sHSPs break down amyloid fibril structure in vitro and induce oligomeric assemblies. Prokaryotic protein overexpression thus mimics the conditions encountered in the cell under stress and allows the structures of Aβ aggregation intermediate states to be investigated under native‐like conditions, which is not otherwise technically possible. We show that IB40/IB42 fulfil all the requirements to be classified as amyloids: they seed fibril growth, are Congo red positive and show characteristic β‐sheet‐rich CD spectra. However, IB40 and IB42 are much less stable than fibrils formed in vitro and contain significant amounts of non‐β‐sheet regions, as seen from FTIR studies. Quantitative analyses of solution‐state NMR H/D exchange rates show that the hydrophobic cores involving residues V18‐F19‐F20 adopt β‐sheet conformations, whereas the C termini adopt α‐helical coiled‐coil structures. In the past, an α‐helical intermediate‐state structure has been postulated, but could not be verified experimentally. In agreement with the current literature, in which Aβ oligomers are described as the most toxic state of the peptides, we find that IB42 contains SDS‐resistant oligomers that are more neurotoxic than Aβ42 fibrils. E. coli inclusion bodies formed by the Alzheimer's disease β‐amyloid peptides Aβ40 and Aβ42 thus behave structurally like amyloid aggregation intermediate states and open the possibility of studying amyloids in a native‐like, cellular environment.
Nickel‐Loaded Zirconia Catalysts with Large Specific Surface Area for High‐Temperature Catalytic Applications
Authors: Peters Andreas , Nouroozi Fatemeh , Richter Dennis , Lutecki Michal , Gläser Roger
Published: January 2011

Highly porous and thermally stable zirconia is prepared by a template‐assisted route using dodecylamine (DDA) and a post‐treatment in ammonia solution at different pH. The resulting materials are calcined at 700 °C and characterized by elemental analysis, optical emission spectrometry with inductively coupled plasma (ICP‐OES), N2 sorption, XRD, high‐resolution TEM, and, after loading with 5 wt % nickel, also by temperature‐programmed reduction and temperature‐programmed desorption of ammonia (TPDA). With increasing pH of the post‐treatment, the specific surface area increases up to 156 m2 g−1 and the diameter of the predominantly tetragonal crystallites decreases from 10.3 to 5.7 nm, independently of the presence of Ni. The high specific surface area is shown to be a result of the incorporation of silicon (<2.5 wt %) dissolved from the glass vessels during the post‐treatment. Despite the presence of acid sites, the Ni‐loaded zirconia are active and selective catalysts in the dry reforming of CH4 with CO2 at 750 °C. With conversions up to 79 % and H2 selectivities up to 87 %, the catalysts supported on zirconia prepared by the DDA route and ammonia post‐treatment are significantly more active than those with zirconia supports prepared by conventional precipitation or in the absence of silicon or DDA.
Au Nanowire‐on‐Film SERRS Sensor for Ultrasensitive Hg2+ Detection
Authors: Kang Taejoon , Yoo Seung Min , Yoon Ilsun , Lee Sangyeop , Choo Jaebum , Lee Sang Yup , Kim Bongsoo
Published: January 2011

We report an ultrasensitive and selective single nanowire‐on‐film (SNOF) surface‐enhanced resonance Raman scattering (SERRS) sensor for Hg2+ detection based on structure‐switching double stranded DNAs (dsDNAs). Binding of Hg2+ induces conformational changes of the dsDNAs and let a Raman reporter get close to the SNOF structure, thereby turning on SERRS signal. The well‐defined SNOF structure provides a detection limit of 100 pM with improved accuracy in Hg2+ detection. This sensor is stable over a considerable amount of time and reusable after simple treatment. Since this SNOF sensor is composed of a single Au NW on a film, development of a multiplex sensor would be possible by employing NWs modified by multiple kinds of aptamers.
Pure Trinuclear 4 f Single‐Molecule Magnets: Synthesis, Structures, Magnetism and Ab Initio Investigation
Authors: Guo Fu‐Sheng , Liu Jun‐Liang , Leng Ji‐Dong , Meng Zhao‐Sha , Lin Zhuo‐Jia , Tong Ming‐Liang , Gao Song , Ungur Liviu , Chibotaru Liviu F.
Published: January 2011

A family of linear Dy3 and Tb3 clusters have been facilely synthesized from the reactions of DyCl3, the polydentate 3‐methyloxysalicylaldoxime (MeOsaloxH2) ligand with auxiliary monoanionic ligands, such as trichloroacetate, NO3−, OH−, and Cl−. Complexes 1–5 contain a nearly linear Ln3 core, with similar Ln⋅⋅⋅Ln distances (3.6901(4)–3.7304(3) Å for the Dy3 species, and 3.7273(3)–3.7485(5) Å for the Tb3 species) and Ln⋅⋅⋅Ln⋅⋅⋅Ln angles of 157.036(8)–159.026(15)° for the Dy3 species and 157.156(8)–160.926(15)° for the Tb3 species. All three Ln centers are bridged by the two doubly‐deprotonated [MeOsalox]2− ligands and two of the four [MeOsaloxH]− ligands through the N,O‐η2‐oximato groups and the phenoxo oxygen atoms (Dy‐O‐Dy angles=102.28(16)–106.85(13)°; Tb‐O‐Tb angles=102.00(11)–106.62(11)°). The remaining two [MeOsaloxH]− ligands each chelate an outer LnIII center through their phenoxo oxygen and oxime nitrogen atoms. Magnetic studies reveal that both Dy3 and Tb3 clusters exhibit significant ferromagnetic interactions and that the Dy3 species behave as single‐molecule magnets, expanding upon the recent reports of the pure 4f type SMMs.
Two Successive Reactions on a DNA Template: A Strategy for Improving Background Fluorescence and Specificity in Nucleic Acid Detection
Authors: Franzini Raphael M. , Kool Eric T.
Published: January 2011

We report a new strategy for template‐mediated fluorogenic chemistry that results in enhanced performance for the fluorescence detection of nucleic acids. In this approach, two successive templated reactions are required to induce a fluorescence signal, rather than only one. These novel fluorescein‐labeled oligonucleotide probes, termed 2‐STAR (STAR=Staudinger‐triggered α‐azidoether release) probes, contain two quencher groups tethered by separate reductively cleavable linkers. When a 2‐STAR quenched probe successively binds adjacent to two mono‐triphenylphosphine‐(TPP)‐DNAs or one dual‐TPP‐DNA, the two quenchers are released, resulting in a fluorescence signal. Because of the requirement for two consecutive reactions, 2‐STAR probes display an unprecedented level of sequence specificity for template‐mediated probe designs. At the same time, background emission generated by off‐template reactions or incomplete quenching is among the lowest of any fluorogenic reactive probes for the detection of DNA or RNA.
Factors That Control Zeolite L Crystal Size
Authors: Itani Lama , Bozhilov Krassimir N. , Clet Guillaume , Delmotte Luc , Valtchev Valentin
Published: January 2011

Time‐series hydrothermal syntheses from two organic‐cation‐free gels with different compositions were employed to study the factors that control the final size of zeolite L crystals. The first gel had a starting K/Al ratio of 10, whereas in the second one it was three times lower. The relatively simple chemical composition of the starting gels and the combination of complementary characterization methods allowed us to track down the different stages of transformation of the initial amorphous gels into zeolite crystals and the factors that control the nucleation and growth processes. The role of the starting mixture components in the formation of the primary amorphous particles was explored. It was found that the profoundly different reaction kinetics in the two systems are caused by the difference in diffusion rates, which in turn are controlled by the extent of the polymerization reactions at room temperature during mixing of the starting components prior to hydrothermal treatment. As a consequence, nucleation is fast and ubiquitous in the first system with higher water content and K/Al ratio, whereas it is slow and sporadic in the second system with lower water content and K/Al ratio. Ultimately, these differences in the kinetics lead to the formation of two distinctly different patterns of crystal‐size distribution, with a large number of small nanocrystals in the first sample and fewer large crystals in the second sample. The new findings put zeolite crystal growth on a rational basis that would enable the control of zeolite crystal size in similar organic‐template‐free systems.
Regioselectivity of the Claisen Rearrangement in meta‐Allyloxy Aryl Ketones: An Experimental and Computational Study, and Application in the Synthesis of (R)‐(−)‐Pestalotheol D
Authors: Lucas Catherine L. , Lygo Barry , Blake Alexander J. , Lewis William , Moody Christopher J.
Published: January 2011

A study of the regioselectivity of the Claisen rearrangement of meta‐allyloxy aryl ketones showed that the electron‐withdrawing carbonyl group has a major influence and strongly directs rearrangement to the more hindered ortho position. However, when the ketone is part of a ring structure, its electronic effect can be negated by conversion into its triisopropylsilyl enol ether, which dramatically reverses the regiochemistry of the Claisen rearrangement. DFT calculations suggest that the effect is electronic although there is also a steric effect of the bulky silyl group. This strategy for influencing the regiochemical outcome of the Claisen rearrangement was then employed in a short synthesis of the furo[2,3‐g]chromene, (−)‐pestalotheol D, that confirms the absolute stereochemistry of the natural product.
Geometry Relations with Bed Load Formulae for Alluvial Boundaries
Authors: Yilmaz Levent
Published: January 2011

Employing bed load formulae hydraulic geometry relations were derived for stream width, sediment transport velocity, and bed slope. The relations were examined in terms of friction factor, bed load discharge, bed load diameter, and water discharge. Two fundamental approaches to the prediction of hydraulic geometry have been developed. The first and most widely adopted approach is based on empirical equations whereas the second is based on solution of the governing equations of flow. The applied bed load formulae belong to different authors. Here, the comparison with the other derived relations is presented.
Evaluation of a Novel Control Method on Biofilm Parameters in an Aerated Submerged Fixed‐bed Biofilm Reactor
Authors: Trojanowicz Karol , Wojcik Wlodzimierz , Styka Wieslawa , Baczynski Tomasz
Published: January 2011

One of the critical technological parameter in operation of aerated submerged fixed‐bed biofilm reactor (ASFBBR) is the control over process of biofilm detachment. Both, an excessive growth of biomass with its accumulation in the bioreactor and an exceeded biofilm detachment rate, cause serious operational and technological problems. The studies presented in this paper demonstrate that in an ASFBBR reactor with a PVC bed carrier media, an effective way to maintain a proper shear stress acting on the biofilm and causing its detachment could be an internal recirculation of wastewater instead of backwashing with wastewater or air flushing. In case of polishing of oil‐refinery wastewater with average COD loading rate equal to 9 g COD/(m2 day), the minimum value of the hydraulic loading rate in such reactor is 1.9 m3/(m2 h), at which there was no excessive growth of biofilms. Despite a significant decrease of the biofilms thickness and amount of biomass in the reactor, there was no significant decline in the efficiency of pollutant removal from oil‐refinery wastewater, which made it possible to obtain the quality of effluent at the outlet of the bioreactor significantly below the water permits and standards.
Surfactant Enhance DLLME/FO‐LADS: Assay of Malachite Green Level in Aquatic Environment of Trout Fish
Authors: Bidari Araz , Ganjali Mohammad Reza , Norouzi Parviz
Published: January 2011

Malachite green (MG), a traditional agent used in aquaculture although is not approved; its low cost and high efficacy make illicit use likely. We developed a small‐scale, simple, and sensitive dispersive liquid–liquid microextraction procedure for the assay of trace amounts of MG in aquatic environment of Trout fish. Fiber optic‐linear array detection spectrophotometry with charge‐coupled device detector benefiting from a microcell was used for this purpose. The method is based on enhancement effect of an anionic surfactant on the extraction of MG in to very fine multidroplets of microextraction solvent which made assisted by disperser solvent. Under the optimum conditions, the enrichment factor 77.5 was obtained from a 5‐mL water sample. The calibration graph was linear up to 5 × 10−7 mol L−1 with detection limit of 1 × 10−8 mol L−1. The relative standard deviation for seven replicate measurements of 4 × 10−7 and 5 × 10−8 mol L−1 of MG were 3.3 and 4.5%, respectively.
Dividing the spoils of growth and the cell cycle: The fission yeast as a model for the study of cytokinesis
Authors: Goyal Anupama , Takaine Masak , Simanis Viesturs , Nakano Kentaro
Published: January 2011

Cytokinesis is the final stage of the cell cycle, and ensures completion of both genome segregation and organelle distribution to the daughter cells. Cytokinesis requires the cell to solve a spatial problem (to divide in the correct place, orthogonally to the plane of chromosome segregation) and a temporal problem (to coordinate cytokinesis with mitosis). Defects in the spatiotemporal control of cytokinesis may cause cell death, or increase the risk of tumor formation [Fujiwara et al., 2005 (Fujiwara T, Bandi M, Nitta M, Ivanova EV, Bronson RT, Pellman D. 2005. Cytokinesis failure generating tetraploids promotes tumorigenesis in p53‐null cells. Nature 437:1043–1047); reviewed by Ganem et al., 2007 (Ganem NJ, Storchova Z, Pellman D. 2007. Tetraploidy, aneuploidy and cancer. Curr Opin Genet Dev 17:157–162.)]. Asymmetric cytokinesis, which permits the generation of two daughter cells that differ in their shape, size and properties, is important both during development, and for cellular homeostasis in multicellular organisms [reviewed by Li, 2007 (Li R. 2007. Cytokinesis in development and disease: variations on a common theme. Cell Mol Life Sci 64:3044–3058)]. The principal focus of this review will be the mechanisms of cytokinesis in the mitotic cycle of the yeast Schizosaccharomyces pombe. This simple model has contributed significantly to our understanding of how the cell cycle is regulated, and serves as an excellent model for studying aspects of cytokinesis. Here we will discuss the state of our knowledge of how the contractile ring is assembled and disassembled, how it contracts, and what we know of the regulatory mechanisms that control these events and assure their coordination with chromosome segregation. © 2011 Wiley‐Liss, Inc.
Sarcomere length fluctuations and flow in capillary endothelial cells
Authors: Russell Robert J. , Grubbs Alexandria Y. , Mangroo Sunil P. , Nakasone Sandra E. , Dickinson Richard B. , Lele Tanmay P.
Published: January 2011

Tensile force within non‐muscle tissue cells is generated in actomyosin stress fibers, which are composed of contractile units called sarcomeres. The number of sarcomeres and sarcomere lengths dynamically change in the cell but the mechanisms by which these processes occur are not understood. Using live cell imaging of labeled sarcomeres, we show that sarcomere lengths continually fluctuate, with a fluctuation relaxation time of about 20 min. New sarcomeres are formed at focal adhesions and are convected into the fiber at a speed that is independent of focal adhesion size, suggesting that the speed is independent of tension. Furthermore sarcomeres were observed to disappear at specific points or “sinks” along the stress fibers. These results show that stress fibers are highly dynamic structures despite their relatively static morphology, with nascent sarcomeres forming and being incorporated into the fiber at a nearly uniform, tension‐independent velocity throughout the cell. The fluctuating length of individual sarcomeres under constant tension is consistent with a model whereby sarcomere contraction/expansion speed, rather than sarcomere length, is modulated by tension. © 2011 Wiley‐Liss, Inc.