bluuebunny/crossref_metadata_2025 huggingface dataset:
Particulate organic carbon : natural radionuclide ratios in zooplankton and their freshly produced fecal pellets from the NW Mediterranean (MedFlux 2005)
Authors: Rodriguez y Baena Alessia M. , Fowler Scott W. , Miquel Juan Carlos
Published: July 2010

To discern controls on particulate organic carbon (POC) : natural radionuclide (RN) ratio variability in order to enhance the accuracy of water column radionuclide‐based carbon flux estimates, 234Th, 210Po, and POC were analyzed in seven size classes of mixed micro‐ and mesoplankton (1‐1,500‐µm size range), in larger zooplankton from different taxa (salps, euphausiids, copepods, pteropods), and in freshly produced feces from zooplankton collected during spring in the NW Mediterranean. POC:RN ratios in zooplankton ranged between 120 and 11,600 and between 89 and 9,200 µmol dpm−1 for 234Th and 210Po, respectively. In fecal pellets, POC:RN ratios were one to three orders of magnitude lower for 234Th and 3‐fold to 30‐fold lower for 210Po; the only exception was euthecosome pteropods, which had a higher POC: 210Po ratio in their pellets than in their whole bodies. Significant increases in POC:RN ratios with organism size were best described by a power relationship for POC: 234Th (p < 0.0006) and a saturation exponential equation for POC: 210Po (with a constant POC: 210Po ratio above 70 µm; p < 0.004), suggesting that the observed trend most likely results from surface adsorption processes for 234Th and food chain bioaccumulation for 210Po. This inference is further supported by the observation that, for the >33‐µm size classes, 210Po specific activity correlates negatively with the surface : volume ratio, while 234Th correlates positively with it (p < 0.004 and p < 0.001, respectively). POC:RN ratios vary greatly among species and to a lesser extent among fecal pellet types, most probably due to differences in zooplankton feeding strategies. Partial removal of most zooplankton “wimmers” from trap samples would not likely confound assessment of 234Th flux; however, it could considerably bias similar measurements of 210Po flux as well as those of POC:RN ratios.
Wood biofilm as a food resource for stream detritivores
Authors: Eggert S. L. , Wallace J. B.
Published: July 2010

Published assimilation efficiencies indicate that leaf detritus is a more nutritious food for stream invertebrates than wood. Some studies, however, suggest that wood and wood biofilms (epixylon) may be an important but overlooked resource. We measured assimilation efficiencies of three detritivores for leaves and epixylon and compared attributes of grazed versus ungrazed wood epixylon to assess its use by detritivores. Pycnopsyche gentilis (Trichoptera), Tipula abdominalis (Diptera), and Tallaperla spp. (Plecoptera) assimilated epixylon more efficiently (26–36%) than leaf detritus (9–17%). Epixylon assimilation efficiencies were T. abdominalis > Tallaperla spp. > P. gentilis. Grazed wood had significantly lower microbial respiration rates, bacteria densities and biomass, fungal and chlorophyll a biomass, and biofilm ash‐free dry mass than ungrazed wood, indicating that detritivores fed on epixylon. Detritivores ingested leaves at a higher rate (0.09–0.47 g g−1 d−1) than epixylon (0.04–0.07 g g−1 d−1). Assimilation rates, which incorporate both assimilation efficiency and ingestion rate, however, indicated that Tallaperla spp. and T. abdominalis were better able to use epixylon than leaves, whereas P. gentilis was more efficient at using leaves. Wood biofilm is readily ingested and assimilated by some stream detritivores and may serve as an important but overlooked food resource in stream food webs.
Evaluating a 3-D transport model of atmospheric CO2 using ground-based, aircraft, and space-borne data
Authors: Feng L. , Palmer P. I. , Yang Y. , Yantosca R. M. , Kawa S. R. , Paris J.-D. , Matsueda H. , Machida T.
Published: July 2010

Abstract. We evaluate the GEOS-Chem atmospheric transport model (v8-02-01) of CO2 over 2003–2006, driven by GEOS-4 and GEOS-5 meteorology from the NASA Goddard Global Modelling and Assimilation Office, using surface, aircraft and space-borne concentration measurements of CO2. We use an established ensemble Kalman filter to estimate a posteriori biospheric+biomass burning (BS+BB) and oceanic (OC) CO2 fluxes from 22 geographical regions, following the TransCom 3 protocol, using boundary layer CO2 data from a subset of GLOBALVIEW surface sites. Global annual net BS+BB+OC CO2 fluxes over 2004–2006 for GEOS-4 (GEOS-5) meteorology are −4.4±0.9 (−4.2±0.9), −3.9±0.9 (−4.5±0.9), and −5.2±0.9 (−4.9±0.9) Pg C yr−1 , respectively. The regional a posteriori fluxes are broadly consistent in the sign and magnitude of the TransCom-3 study for 1992–1996, but we find larger net sinks over northern and southern continents. We find large departures from our a priori over Europe during summer 2003, over temperate Eurasia during 2004, and over North America during 2005, reflecting an incomplete description of terrestrial carbon dynamics. We find GEOS-4 (GEOS-5) a posteriori CO2 concentrations reproduce the observed surface trend of 1.91–2.43 ppm yr−1, depending on latitude, within 0.15 ppm yr−1 (0.2 ppm yr−1) and the seasonal cycle within 0.2 ppm (0.2 ppm) at all latitudes. We find the a posteriori model reproduces the aircraft vertical profile measurements of CO2 over North America and Siberia generally within 1.5 ppm in the free and upper troposphere but can be biased by up to 4–5 ppm in the boundary layer at the start and end of the growing season. The model has a small negative bias in the free troposphere CO2 trend (1.95–2.19 ppm yr−1) compared to AIRS data which has a trend of 2.21–2.63 ppm yr−1 during 2004–2006, consistent with surface data. Model CO2 concentrations in the upper troposphere, evaluated using CONTRAIL (Comprehensive Observation Network for TRace gases by AIrLiner) aircraft measurements, reproduce the magnitude and phase of the seasonal cycle of CO2 in both hemispheres. We generally find that the GEOS meteorology reproduces much of the observed tropospheric CO2 variability, suggesting that these meteorological fields will help make significant progress in understanding carbon fluxes as more data become available.
Shallow soil moisture – ground thaw interactions and controls – Part 2: Influences of water and energy fluxes
Authors: Guan X. J. , Spence C. , Westbrook C. J.
Published: July 2010

Abstract. The companion paper (Guan et al., 2010) demonstrated variable interactions and correlations between shallow soil moisture and ground thaw in soil filled areas along a wetness spectrum in a subarctic Canadian Precambrian Shield landscape. From wetter to drier, these included a wetland, peatland and soil filled valley. Herein, water and energy fluxes were examined for these same subarctic study sites to discern the key controlling processes on the found patterns. Results showed the presence of surface water was the key control in variable soil moisture and frost table interactions among sites. At the peatland and wetland sites, accumulated water in depressions and flow paths maintained soil moisture for a longer duration than at the hummock tops. These wet areas were often locations of deepest thaw depth due to the transfer of latent heat accompanying lateral surface runoff. Although the peatland and wetland sites had large inundation extent, modified Péclet numbers indicated the relative influence of external and internal hydrological and energy processes at each site were different. Continuous inflow from an upstream lake into the wetland site caused advective and conductive thermal energies to be of equal importance to ground thaw. The absence of continuous surface flow at the peatland and valley sites led to dominance of conductive thermal energy over advective energy for ground thaw. The results suggest that the modified Péclet number could be a very useful parameter to differentiate landscape components in modeling frost table heterogeneity. The calculated water and energy fluxes, and the modified Péclet number provide quantitative explanations for the shallow soil moisture-ground thaw patterns by linking them with hydrological processes and hillslope storage capacity.
Pure and Saturated Red Electroluminescent Polyfluorenes with Dopant/Host System and PLED Efficiency/Color Purity Trade‐Offs
Authors: Chen Lei , Zhang Baohua , Cheng Yanxiang , Xie Zhiyuan , Wang Lixiang , Jing Xiabin , Wang Fosong
Published: July 2010

Three kinds of red electroluminescent (EL) polymers based on polyfluorene as blue host and 2,1,3‐benzothiadiazole derivatives with different emission wavelengths as red dopant units on the side chain are designed and synthesized. The influence of the photoluminescence (PL) efficiencies and emission wavelengths of red dopants on the EL efficiencies and color purities of the resulting polyfluorene copolymers of dopant/host system is investigated by adjusting the electron donating ability of the donor units in D‐π‐A‐D typed 2,1,3‐benzothiadiazole derivatives. The devices of these red‐emitting polymers realize remarkable EL efficiency/color purity trade‐offs. The single‐layer devices with the configuration of ITO/PEDOT:PSS/Polymer/Ca/Al show pure red emission at 624 nm with a luminous efficiency of 3.83 cd A−1 and CIE of (0.63, 0.35) for PFR1, saturated red emission at 636 nm with a luminous efficiency of 2.29 cd A−1 and CIE of (0.64, 0.33) for PFR2, respectively. By introduction of an additional electron injection layer PF‐EP(Ethanol soluble phosphonate‐functionalized polyfluorene), high performance pure and saturated red emission two‐layer devices (ITO/PEDOT:PSS/Polymer/PF‐EP/LiF/Al) were achieved with maximum luminous efficiencies of 5.50 cd A−1 and CIE of (0.62, 0.35) for PFR1, 3.10 cd A−1 and CIE of (0.63, 0.33) for PFR2, respectively, which are the best results for pure and saturated fluorescent red EL polymers reported so far.
Controlled Synthesis of One‐Dimensional Inorganic Nanostructures Using Pre‐Existing One‐Dimensional Nanostructures as Templates
Authors: Liang Hai‐Wei , Liu Shuo , Yu Shu‐Hong
Published: July 2010

Template‐directed strategy has become one of the most popular methods for the fabrication of one‐dimensional (1D) nanostructures with uniform size and controllable physical dimensions in recent years. This Review article describes the recent progress in the synthesis of 1D inorganic nanostructures by using suitable templates. A brief survey on the templating method based on the organic templates and porous membrane is firstly given. Then, the article is focused on recent emerging synthetic strategies by templating against the pre‐existing 1D nanostructures using different physical and chemical transformation techniques, including epitaxial growth, nonepitaxial growth, direct chemical transformation, solid‐state interfacial diffusion reaction, and so on. The important reactivity role of the 1D nanostructures will be emphasized in such transformation process. Finally, we conclude this paper with some perspectives and outlook on this research topic.
Patterning of soft polydimethylsiloxane elastomers using plasma etching
Authors: Bjørnsen Geir , Roots Jaan , Henriksen Lars
Published: July 2010

Soft polydimethylsiloxane (PDMS) elastomers spin coated on silicon wafers are patterned using plasma etching. The elastomers are formed by mixing vinyl‐terminated PDMS (prepolymer) and crosslinker containing hydride sites. The elastomers are made softer by adding either excess prepolymer, excess crosslinker, or swelling agent. The different elastomers were etched using reactive ion etching, an old and well established processing technology in the microelectronic and MEMS industry. The etch rate and profiles of the etched surfaces were dependent on the process pressure. The dependence was different for the different elastomers. It was found that at low pressure, the etch rate was dependent on the shear modulus. At high pressures, the etch rate was dependent on the chemical composition of the elastomer. The results for the swollen elastomers were different from those for the nonswollen elastomers. The etch rate was lower and the profiles of the etched cavities were different. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Thermal stability, aging properties, and flame resistance of NR‐based nanocomposite
Authors: Khanlari Samaneh , Kokabi Mehrdad
Published: July 2010

Polymer/clay nanocomposites have some unique properties due to combination of flame resistance and improved mechanical and thermal stability properties which are important to enhance the material quality and performance. The objective of this work was to investigate the effect of organically modified montmorillonite (org‐MMT) on the thermal and flame retardant as well as hardness and mechanical properties of the nanocomposites based on the natural rubber (NR). It was shown that by the addition of 3 wt % of org‐MMT to NR, its aging hardness rise was decreased more than 55% and the ignition time was delayed about 150%. The reduction in heat release rate peak value was equal to 54% compared to the pristine NR. Addition of org‐MMT improved the thermal stability of the NR. Furthermore, nanocomposites which were calendared before curing showed much more thermal stability and fire resistance than those which contained similar amount of organoclay. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of microwave irradiation on the physical properties and structures of wool fabric
Authors: Xue Zhao , Jin‐Xin He
Published: July 2010

Microwaves are high frequency radio waves which are capable of penetrating many materials and causing heat to be generated in the process. To investigate the effect of microwave irradiation on the physical property, chemical structure, surface morphological structure, and fine structure of wool fabric, wool fabric was treated with microwave irradiation under variety of conditions in terms of the power and the time of microwave treatment. The breaking strength, breaking elongation, and whiteness of the treated wool fabric in different humid state were investigated. The structures of the untreated and treated wool were investigated with Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), and Laser Raman spectroscopy (LRS). The results show that the physical properties of the treated wool fabrics were changed with microwave irradiation time and power. The chemical structure had not significant change. The surface morphological structure, the concentration of cystine SS bonds and crystallinity of the treated wool were changed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and application of a series of novel anionic acrylamide polymers with cyclodextrin sides
Authors: Zou Changjun , Wu Haomin , Ma Lan , Lei Ying
Published: July 2010

In this article, the synthesis and characterization of a new class of macromolecule water‐soluble polymers with cyclodextrin sides were presented, which possess molecular recognition function. The polymer composed with three functional monomers was investigated through an infrared spectrometry and a scanning electron microscope. Then, the rheological properties and the interaction with surfactant of this series of polymer samples were evaluated and compared with polyacrylamide to prove that they have superior rheology performance. Also, through the adsorption experiment it can be seen that the polymer has excellent performance in polymer flooding, and it can effectively reduce over 20% of the surfactant loss caused by stratum absorption in the process of polymer/surfactant flooding. These have laid a theoretical foundation for its application to enhance oil recovery. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Crystallinity, conductivity, and magnetic properties of PVDF‐Fe3O4 composite films
Authors: Bhatt Aarti S. , Bhat D. Krishna , Santosh M. S.
Published: July 2010

The formation of Fe3O4 nanoparticles by hydrothermal process has been studied. X‐ray Diffraction measurements were carried out to distinguish between the phases formed during the synthesis. Using the synthesized Fe3O4 nanoparticles, poly(vinyledene fluoride)‐Fe3O4 composite films were prepared by spin coating method. Scanning electron microscopy of the composite films showed the presence of Fe3O4 nanoparticles in the form of aggregates on the surface and inside of the porous polymer matrix. Differential Scanning calorimetry revealed that the crystallinity of PVDF decreased with the addition of Fe3O4. The conductitivity of the composite films was strongly influenced by the Fe3O4 content; conductivity increased with increase in Fe3O4 content. Vibration sample magnetometry results revealed the ferromagnetic behavior of the synthesized iron oxide nanoparticles with a Ms value of 74.50 emu/g. Also the presence of Fe3O4 nanoparticles rendered the composite films magnetic. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Association of familial Mediterranean fever–related MEFV variations with ankylosing spondylitis
Authors: Cosan Fulya , Üstek Duran , Oku Basar , Duymaz‐Tozkir Julide , Cakiris Aris , Abaci Neslihan , Ocal Lale , Aral Orhan , Gül Ahmet
Published: July 2010

Objective

The pathogenesis of ankylosing spondylitis (AS) has a strong genetic contribution. Familial Mediterranean fever (FMF) is an autosomal recessively inherited autoinflammatory disorder caused by MEFV gene missense variations, and a clinical association between FMF and AS has been reported previously. The aim of this study was to analyze the association of common MEFV variations (M694V, M680I, V726A, and E148Q) with AS in a group of Turkish patients.

Methods

The study group comprised 193 patients with AS and 103 matched healthy control subjects. All individuals were genotyped for 4 MEFV variations and HLA–B27 using genomic DNA, and association of the variations with the clinical and laboratory features of the patients was analyzed.

Results

The MEFV missense variations were significantly more frequent in patients with AS (22.3%) compared with healthy control subjects (9.7%; odds ratio [OR] 2.67, 95% confidence interval [95% CI] 1.28–5.56). This difference was more prominent for exon 10 variations (M694V, V726A, M680I) (OR 3.75, 95% CI 1.41–9.97), especially for the most‐penetrant variation M694V (OR 4.73, 95% CI 1.39–16.12). MEFV variations were more frequent in HLA–B27–negative patients with AS, and the difference was statistically significant in patients carrying exon 10 variants.

Conclusion

FMF‐related MEFV variations are associated with AS, and these variations may contribute to the pathogenesis of AS, especially in populations in which the prevalence of FMF is high.
Mortality among infants with birth defects: Joint effects of size at birth, gestational age, and maternal race/ethnicity
Authors: Nembhard Wendy N. , Salemi Jason L. , Ethen Mary K. , Fixler David E. , Canfield Mark A.
Published: July 2010

BACKGROUND

We examined the separate and joint effects of gestational age, size at birth and maternal race/ethnicity on early childhood survival among 48,391 singleton infants with major birth defects.

METHODS

Texas Birth Defects Registry data were linked to death records and the National Death Index to ascertain deaths. Gestational age categories were preterm or term birth; size at birth included small for gestational age (SGA), appropriate for gestational age (AGA), and large for gestational age (LGA). Kaplan‐Meier survival estimates were calculated, and Cox‐proportional hazards models were used to calculate hazard ratios (HR) and 95% confidence intervals (CI) to determine risk of death after adjusting for covariates.

RESULTS

Overall, relative to non‐Hispanic (NH) ‐whites, NH‐blacks, and Hispanics had a 51 and 10% greater risk of death during early childhood, respectively. Compared to NH‐whites born term and AGA (survival = 97%), Hispanic children born SGA and preterm had the greatest risk of death (HRa = 6.1; 95% CI, 5.2, 7.2) and the lowest early childhood survival (76%), followed by SGA preterm NH‐blacks (HRa = 4.8; 95% CI, 3.6, 6.5; survival = 81%) and SGA preterm NH‐whites (HRa = 4.5; 95% CI, 3.7, 5.6; survival = 83%). Children born LGA at term had no increased risk of mortality regardless of maternal race/ethnicity.

CONCLUSIONS

The joint effect of gestational age and size at birth had greatest impact on childhood mortality. Additional population based studies are needed to better understand causes of racial/ethnic disparities in mortality among children with birth defects. Birth Defects Research (Part A), 2010. © 2010 Wiley‐Liss, Inc.
Evidence for linkage of the bladder exstrophy‐epispadias complex on chromosome 4q31.21‐22 and 19q13.31‐41 from a consanguineous iranian family
Authors: Reutter Heiko , Rüschendorf Franz , Mattheisen Manuel , Draaken Markus , Bartels Enrika , Hübner Norbert , Hoffmann Per , Payabvash Seyedmedhi , Saar Kathrin , Nöthen Markus M. , Kajbafzadeh Abdol‐Mohammad , Ludwig Michael
Published: July 2010

BACKGROUND:

The bladder exstrophy‐epispadias complex (BEEC) is a spectrum of anomalies involving the abdominal wall, pelvis, urinary tract, genitalia, and, occasionally, the spine and anus. Although BEEC typically occurs sporadically, families with two or more affected members have been reported. The present authors previously conducted a genome‐wide linkage analysis in two multiply affected (multiplex) families (one of German and one of Spanish origin), which revealed several chromosomal regions compatible with linkage. In the present study, genome‐wide linkage analysis was performed in a recently reported consanguineous Iranian multiplex family with an affected sibling pair: a female with epispadias and a male with classic exstrophy of the bladder.

METHODS:

The Affymetrix 250K Sty chip (238,304 single nucleotide polymorphisms) was used to genotype the parents and four children, including the two affected siblings. Parametric and nonparametric linkage analyses were performed.

RESULTS:

Parametric linkage analysis under a recessive model with complete penetrance identified seven loci with LOD scores >1.6 (1p33, 4q31.21‐22, 9q22.33, 12q13.13‐2, 13q12.12‐13, 18q23, and 19q13.31‐41). These results were supported by nonparametric linkage analysis. Haplotype analysis showed that the affected individuals were homozygous identical by descent for all seven regions. Two of these regions overlapped with regions observed previously in the Spanish family —one on chromosome 4q31.21‐22, and the other on chromosome 19q13.31‐41.

CONCLUSION:

These results suggest that chromosomal regions 4q31.21‐22 and 19q13.31‐41 are likely to harbor genes for an autosomal recessive form of BEEC. Birth Defects Research (Part A), 2010. © 2010 Wiley‐Liss, Inc.
Rectal washout and local recurrence of cancer after anterior resection
Authors: Kodeda K , Holmberg E , Jörgren F , Nordgren S , Lindmark G
Published: July 2010

Background

Adenocarcinomas of the rectum shed viable cells, which have the ability to implant. Intraoperative rectal washout decreases the amount and viability of these cells, but there is no conclusive evidence of the effect of rectal washout on local recurrence after rectal cancer surgery.

Methods

Data were analysed from a population-based registry of patients who had anterior resection from 1995 to 2002 and were followed for 5 years. Rectal washout was performed at the discretion of the surgeon. National inclusion of patients with rectal cancer and follow-up was near complete (approximately 97 and 98 per cent respectively).

Results

A total of 4677 patients were analysed (3749 who had washout, 851 no washout and 77 with information missing); 52·0 per cent of patients in the washout group and 41·4 per cent in the no-washout group had preoperative radiotherapy (P < 0·001). Local recurrence rates were 6·0 and 10·2 per cent respectively (P < 0·001). Univariable and multivariable logistic regression analyses produced odds ratios that favoured washout: 0·56 (95 per cent confidence interval (c.i.) 0·43 to 0·72) and 0·61 (0·46 to 0·80) respectively (both P < 0·001). In multivariable analysis restricted to patients who had curative surgery, the odds ratio was 0·59 (95 per cent c.i. 0·44 to 0·78; P < 0·001).

Conclusion

There was a more favourable outcome in patients after rectal washout than without.
Emotional display rules and emotion self‐regulation: Associations with bullying and victimization in community‐based after school programs
Authors: Garner Pamela W. , Hinton Tiffany Stowe
Published: July 2010

We explored linkages among different components of emotional competence and bullying and victimization in children enrolled in community after school programs. Seventy‐seven children were recruited from after school programs and their display rule knowledge for sadness and anger was evaluated. Their emotion self‐regulation skills and bullying experiences were also assessed. Knowledge of display rules for sadness was a negative predictor of physical victimization whereas emotional lability/negativity was positively related to bullying. Boys bullied more than girls and family income was negatively related to bullying and emotional lability/negativity and positively associated with emotion self‐regulation. Emotion self‐regulation mediated the relation between family income and bullying. Analyses also suggested that bullies and bully‐victims had poorer emotion self‐regulation skills than non‐bullies/victims or victims. Copyright © 2010 John Wiley & Sons, Ltd.
Rapid Screening of Lectins for Multivalency Effects with a Glycodendrimer Microarray
Authors: Parera Pera Núria , Branderhorst Hilbert M. , Kooij Raymond , Maierhofer Caroline , van der Kaaden Marjolein , Liskamp Rob M. J. , Wittmann Valentin , Ruijtenbeek Rob , Pieters Roland J.
Published: July 2010

Multivalency is an important phenomenon in protein–carbohydrate interactions. In order to evaluate glycodendrimers as multivalent inhibitors of carbohydrate binding proteins, we displayed them on a microarray surface. Valencies were varied from 1 to 8, and corrections were made for the valencies so that all surfaces contained the same amount of the sugar ligand. Five different carbohydrates were attached to the dendrimers. A series of fluorescent lectins was evaluated, and for each of them a binding profile was obtained from a single experiment showing both the specificity of the lectin for a certain sugar and whether it prefers multivalent ligands or not. Very distinct binding patterns were seen for the various lectins. The results were rationalized with respect to the interbinding distances of the lectins.
ChemInform Abstract: A Convenient Transformation of 2‐Alkylidenecycloalkanones into Alkyl‐Substituted Bicyclo[n.1.0]alkan‐1‐ols: Application to the Synthesis of Capsaicin.
Authors: Kananovich Dzmitry G. , Zubrytski Dzmitry M. , Kulinkovich Oleg G.
Published: July 2010

An efficient procedure is developed via conditions A) (formation of β‐iodoketones) followed by conditions B) in the presence of either TmsCl or TiCl(O‐iPr)3.
Conformational dynamics of actin: Effectors and implications for biological function
Authors: Hild Gábor , Bugyi Beáta , Nyitrai Miklós
Published: July 2010

Actin is a protein abundant in many cell types. Decades of investigations have provided evidence that it has many functions in living cells. The diverse morphology and dynamics of actin structures adapted to versatile cellular functions is established by a large repertoire of actin‐binding proteins. The proper interactions with these proteins assume effective molecular adaptations from actin, in which its conformational transitions play essential role. This review attempts to summarise our current knowledge regarding the coupling between the conformational states of actin and its biological function.
Deoxycitidine kinase is associated with prolonged survival after adjuvant gemcitabine for resected pancreatic adenocarcinoma
Authors: Maréchal Raphaël , Mackey John R. , Lai Raymond , Demetter Pieter , Peeters Marc , Polus Marc , Cass Carol E. , Salmon Isabelle , Devière Jacques , Van Laethem Jean‐Luc
Published: July 2010

BACKGROUND:

Gemcitabine (2′,2′‐difluorodeoxycytidine) administration after resection of pancreatic cancer improves both disease‐free survival (DFS) and overall survival (OS). Deoxycytidine kinase (dCK) mediates the rate‐limiting catabolic step in the activation of gemcitabine. The authors of this report studied patient outcomes according to the expression of dCK after a postoperative gemcitabine‐based chemoradiation regimen.

METHODS:

Forty‐five patients with resected pancreatic adenocarcinoma received adjuvant gemcitabine based‐therapy in the context of multicenter phase 2 studies. Their tumors were evaluated retrospectively for dCK protein expression by immunohistochemistry. A composite score based on the percentage of dCK‐positive cancer cells and the intensity of staining was generated, and the results were dichotomized at the median values.

RESULTS:

The median follow‐up was 19.95 months (95% confident interval [CI], 3.3‐107.4 months). The lymph node (LN) ratio and dCK protein expression were significant predictors of DFS and OS in univariate analysis. On multivariate analysis, dCK protein expression was the only independent prognostic variable (DFS: hazard ratio [HR], 3.48; 95% CI, 1.66‐7.31; P = .001; OS: HR, 3.2; 95% CI,1.44‐7.13; P = .004).

CONCLUSIONS:

dCK protein expression was identified as an independent and strong prognostic factor in patients with resected pancreatic adenocarcinoma who received adjuvant gemcitabine therapy. The authors concluded that it deserves prospective evaluation as a predictive biomarker for patient selection. Cancer 2010. © 2010 American Cancer Society.
Implicit processing goals combine with explicit goal standards to motivate performance through underlying comparison processes
Authors: Bittner Jenny V.
Published: July 2010

This research investigates whether explicit goals interact with implicit processing goals that are activated simultaneously. Based on the idea that (a) explicit goals are used as comparison standards, and (b) implicit processing goals have motivational consequences by influencing the process of comparison with those standards, these studies elucidate the mechanism by which explicit and implicit goals combine to influence task performance. Study 1 demonstrated that a primed goal to process similarities versus differences interacted with explicit goal standards in influencing subsequent task performance. High explicit goals resulted in better performance when participants had the implicit goal of processing similarities, whereas low explicit goals resulted in better performance when the implicit goal was processing differences. Study 2 provided evidence that perceived similarity to a target person is a critical factor for the pursuit of explicit goals and that this similarity influences task performance in the same way as the primed goal to process similarities. Study 3 indicated that processing similarities results from assimilation to a moderately high goal, whereas processing differences is the result of contrasting away from an extremely high goal. These findings confirm that implicit processing of similarities versus differences has a combined influence with explicit goals on task performance. Copyright © 2010 John Wiley & Sons, Ltd.
Effects of functionalized fullerenes on bifenthrin and tribufos toxicity to Daphnia magna: Survival, reproduction, and growth rate
Authors: Brausch Kathryn A. , Anderson Todd A. , Smith Philip N. , Maul Jonathan D.
Published: July 2010

Incorporation of carbon nanomaterials into industrial and consumer products is increasing, yet their impact on aquatic ecosystems alone and in chemical mixtures is largely unknown. Carbon nanomaterials may be found in the aquatic environment as mixtures with pesticides because of their proposed use in agriculture as smart delivery systems and nanosensors. The interaction effects of a functionalized fullerene ([1,2-methanofullerene C60]-61-carboxylic acid) (fC60) at 52.8 µg/L and the hydrophobic pesticides bifenthrin and tribufos were examined. The test organism was Daphnia magna, and response variables included 48-h survival, reproduction (bifenthrin, 70-d; tribufos, 21-d), and 10-d growth. Both pesticides reduced D. magna survival and reproduction (p < 0.05). Fullerenes significantly increased bifenthrin acute toxicity but did not significantly affect chronic endpoints or growth (p > 0.05). Median lethal concentrations (LC50s), median inhibition concentrations (IC50s) for days surviving, and IC50s for reproduction were 0.86, 0.55, and 0.49 µg/L for bifenthrin; 0.22, 0.39, and 0.77 µg/L for fC60-bifenthrin mix; 6.63, 9.89, and 5.79 µg/L for tribufos; and 9.17, 8.17, and 6.59 µg/L for fC60–tribufos mix. Mixtures did not affect instantaneous growth rate (p > 0.05). These results suggest that fC60 had little effect on pesticide chronic toxicity but influenced acute toxicity. Given the widespread application of nanotechnology, the influence of nanomaterials on environmental contaminants is an important consideration. Thus, our results may be useful in the development and use of nanotechnology in agricultural practices. Environ. Toxicol. Chem. 2010;29:2600–2606. © 2010 SETAC
Tissue-based risk assessment of great blue heron (Ardea herodias) exposed to PCDD/DF in the Tittabawassee River floodplain, Michigan, USA
Authors: Seston Rita M. , Fredricks Timothy B. , Tazelaar Dustin L. , Coefield Sarah J. , Bradley Patrick W. , Newsted John L. , Kay Denise P. , Fitzgerald Scott D. , Giesy John P. , Zwiernik Matthew J.
Published: July 2010

Concentrations of dioxin-like compounds, primarily polychlorinated dibenzofurans (PCDFs), in soils and sediments of the Tittabawassee River (TR) and associated floodplains downstream of Midland, Michigan, USA, were greater than upstream sites and prompted a site-specific risk assessment of great blue herons (GBH). Tissue exposure of PCDF and polychlorinated dibenzo-p-dioxins (PCDDs) was assessed in multiple GBH tissue types, including blood plasma of adults and eggs, as well as blood plasma, adipose, liver, and muscle of nestlings. Adult GBH exposure was associated with foraging area and age class, with concentrations of PCDD/DF being greater in blood plasma of adult GBH foraging in the TR compared with those foraging in upstream reference areas and in older birds as compared with their younger cohorts. Concentrations of PCDD/DFs and dioxin-like polychlorinated biphenyls (PCBs) in eggs and nestling tissues of GBH collected from rookeries within the TR floodplain were generally similar among rookeries. Mean concentrations of PCDD/DFs in eggs of GBH ranged from 45 to 67 ng/kg, wet weight for the rookeries studied, with a maximum concentration of 210 ng/kg, wet weight observed. Adipose consistently had the greatest concentration of PCDD/DFs of all tissues collected from nestlings of GBH, ranging from 98 to 430 ng/kg, wet weight. Potential for adverse population-level effects from site-specific contaminant exposures were evaluated by comparison with selected toxicity reference values (TRVs). Minimal risk of adverse population-level effects were predicted when exposures measured in tissues of GBH collected from rookeries within the TR were compared with appropriate TRVs. This prediction is consistent with site-specific measures of population condition, which included clutch size and number of nestlings per successful nest. Environ. Toxicol. Chem. 2010;29:2544–2558. © 2010 SETAC
Type 1 T Helper Cells Induce the Accumulation of Myeloid-Derived Suppressor Cells in the Inflamed Tgfb1 Knockout Mouse Liver
Authors: Cripps James G. , Wang Jing , Maria Ann , Blumenthal Ian , Gorham James D.
Published: July 2010

Immune-mediated liver injury in hepatitis is due to activated T cells producing interferon-γ (IFN-γ). It is important to identify negative feedback immune mechanisms that can regulate T cell activity. In this study, we demonstrate that liver inflammation mediated by type 1 T helper (Th1) cells can induce the accumulation of myeloid-derived suppressor cells (MDSCs), pleiomorphic cells capable of modulating T cell–mediated immunity, that heretofore have been studied almost exclusively in the context of tumor-associated inflammation. Mice deficient in the gene encoding transforming growth factor-β1 (

Tgfb1

−/− mice) acutely develop liver necroinflammation caused by IFN-γ–producing clusters of differentiation 4–positive (CD4+) T cells. Liver Th1 cell accumulation was accompanied by myeloid cells expressing CD11b and Gr1, phenotypic hallmarks of MDSCs. Isolated

Tgfb1

−/− liver CD11b+Gr1+ cells were functional MDSCs, readily suppressing T cell proliferation

in vitro

. Pharmacologic inhibitors of inducible nitric oxide (NO) synthase completely eliminated suppressor function. Suppressor function and the production of NO were dependent on cell–cell contact between MDSCs and T cells, and upon IFN-γ, and were specifically associated with the “monocytic” CD11b+Ly6G− Ly6Chi subset of liver

Tgfb1

−/− CD11b+ cells. The rapid accumulation of CD11b+Gr1+ cells in

Tgfb1

−/− liver was abrogated when mice were either depleted of CD4+ T cells or rendered unable to produce IFN-γ, showing that Th1 activity induces MDSC accumulation.

Conclusion:

Th1 liver inflammation mobilizes an MDSC response that, through the production of NO, can inhibit T cell proliferation. We propose that MDSCs serve an important negative feedback function in liver immune homeostasis, and that insufficient or inappropriate activity of this cell population may contribute to inflammatory liver pathology. (Hepatology 2010;)
Risk Factors for Infection During Treatment with Peginterferon alfa and Ribavirin for Chronic Hepatitis C
Authors: Roomer Robert , Hansen Bettina E. , Janssen Harry L. A. , de Knegt Robert J.
Published: July 2010

Neutropenia during treatment with peginterferon alfa and ribavirin for chronic hepatitis C virus (HCV) infection is a common cause of dose reductions of peginterferon alfa. These reductions are performed to prevent bacterial and fungal infections, which are common during HCV treatment and can be attributed to neutropenia. The aims of this study were to investigate the occurrence of infections and their relation to neutropenia and to identify potential risk factors for infections during HCV treatment. In this single-center cohort study, 2,876 visits of 321 patients treated with peginterferon alfa and ribavirin were evaluated for neutropenia, infections, dose reductions, and potential risk factors for infection during HCV treatment. The baseline mean absolute neutrophil count (ANC) was 3,420 cells/μL, and 16 patients had a baseline ANC of <1,500 cells/μL. During treatment, neutropenia, which was defined as ANC <750 cells/μL, was observed in 95 patients (29.7%) and ANC <375/μL was observed in 16 patients (5%). Ninety-six infections were observed in 70 patients (21.8%). Thirteen infections (13.5%) were defined as severe. Infections were not correlated with neutropenia during treatment. Dose reductions did not lead to a decrease in infection rate. Multivariate logistic regression analysis revealed that age >55 years (odds ratio [OR] 2.06, 95% confidence interval [CI] 1.19-3.56,

P

= 0.01) and baseline hyperglycemia (OR 2.17, 95% CI 1.15-4.10,

P

= 0.016) were associated with an increased risk of infection during HCV treatment. Cirrhosis and chronic obstructive pulmonary disease were not risk factors for infection.

Conclusion:

Bacterial infections during treatment with peginterferon alfa and ribavirin are not associated with neutropenia. Older patients and patients with poorly controlled diabetes mellitus have a greater risk of developing infections during HCV treatment. (Hepatology 2010)
Prediction of Sustained Response to Peginterferon Alfa-2b for Hepatitis B e Antigen–Positive Chronic Hepatitis B Using on-Treatment Hepatitis B Surface Antigen Decline
Authors: Sonneveld Milan J. , Rijckborst Vincent , Boucher Charles A. B. , Hansen Bettina E. , Janssen Harry L. A.
Published: July 2010

Serum hepatitis B surface antigen (HBsAg) levels may reflect the immunomodulatory efficacy of pegylated interferon (PEG-IFN). We investigated within a large randomized trial whether quantitative HBsAg levels predict response to PEG-IFN in patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B. Serum HBsAg was measured in samples taken at baseline and weeks 4, 8, 12, 24, 52, and 78 of 221 patients treated with PEG-IFN alfa-2b with or without lamivudine for 52 weeks. HBsAg decline was compared between treatment arms and between responders and nonresponders. Response was defined as HBeAg loss with HBV DNA < 10,000 copies/mL at 26 weeks after treatment (week 78); 43 of 221 (19%) patients achieved a response. One year of PEG-IFN with or without lamivudine resulted in a significant decline in serum HBsAg, which was sustained after treatment (decline 0.9 log IU/mL at week 78,

P

< 0.001). Patients treated with combination therapy experienced a more pronounced on-treatment decline, but relapsed subsequently. Responders experienced a significantly more pronounced decline in serum HBsAg compared to nonresponders (decline at week 52: 3.3 versus 0.7 log IU/mL,

P

< 0.001). Patients who achieved no decline at week 12 had a 97% probability of nonresponse through posttreatment follow-up and no chance of HBsAg loss. In a representative subset of 149 patients similar results were found for prediction through long-term (mean 3.0 years) follow-up.

Conclusion:

PEG-IFN induces a significant decline in serum HBsAg in HBeAg-positive patients. Patients who experience no decline from baseline at week 12 have little chance of achieving a sustained response and no chance of HBsAg loss and should be advised to discontinue therapy with PEG-IFN. (Hepatology 2010)
Endotoxin Accumulation Prevents Carcinogen-Induced Apoptosis and Promotes Liver Tumorigenesis in Rodents
Authors: Yu Le-Xing , Yan He-Xin , Liu Qiong , Yang Wen , Wu Hong-Ping , Dong Wei , Tang Liang , Lin Yan , He Ya-Qin , Zou Shan-Shan , Wang Chao , Zhang Hui-Lu , Cao Guang-Wen , Wu Meng-Chao , Wang Hong-Yang
Published: July 2010

Increasing evidence suggests that the presence of endotoxemia is of substantial clinical relevance to patients with cirrhosis, but it is unclear whether and how gut-derived LPS amplifies the tumorigenic response of the liver. We found that the circulating levels of LPS were elevated in animal models of carcinogen-induced hepatocarcinogenesis. Reduction of LPS using antibiotics regimen in rats or genetic ablation of its receptor Toll-like receptor 4 (TLR4) in mice prevented excessive tumor growth and multiplicity. Additional investigation revealed that TLR4 ablation sensitizes the liver to carcinogen-induced toxicity via blocking NF-κB activation and sensitizing the liver to reactive oxygen species (ROS)-induced toxicity, but lessens inflammation-mediated compensatory proliferation. Reconstitution of

TLR4

-expressing myeloid cells in

TLR4

-deficient mice restored diethylnitrosamine (DEN)-induced hepatic inflammation and proliferation, indicating a paracrine mechanism of LPS in tumor promotion. Meanwhile, deletion of gut-derived endotoxin suppressed DEN-induced cytokine production and compensatory proliferation, whereas

in vivo

LPS pre-challenge promotes hepatocyte proliferation.

Conclusion:

Our data indicate that sustained LPS accumulation represents a pathological mediator of inflammation-associated hepatocellular carcinoma (HCC) and manipulation of the gut flora to prevent pathogenic bacterial translocation and endotoxin absorption may favorably influence liver function in patients with cirrhosis who are at risk of developing HCC. (Hepatology 2010.)
Phosphoinositide 3-Kinase/Protein Kinase B Signaling Pathway Is Involved in Estradiol 17β-D-Glucuronide–Induced Cholestasis: Complementarity with Classical Protein Kinase C
Authors: Boaglio Andrea C. , Zucchetti Andrés E. , Sánchez Pozzi Enrique J. , Pellegrino José M. , Ochoa Justina Elena , Mottino Aldo D. , Vore Mary , Crocenzi Fernando A. , Roma Marcelo G.
Published: July 2010

Estradiol 17β-D-glucuronide (E217G) is an endogenous, cholestatic metabolite that induces endocytic internalization of the canalicular transporters relevant to bile secretion: bile salt export pump (Bsep) and multidrug resistance–associated protein 2 (Mrp2). We assessed whether phosphoinositide 3-kinase (PI3K) is involved in E217G-induced cholestasis. E217G activated PI3K according to an assessment of the phosphorylation of the final PI3K effector, protein kinase B (Akt). When the PI3K inhibitor wortmannin (WM) was preadministered to isolated rat hepatocyte couplets (IRHCs), it partially prevented the reduction induced by E217G in the proportion of IRHCs secreting fluorescent Bsep and Mrp2 substrates (cholyl lysyl fluorescein and glutathione methylfluorescein, respectively). 2-Morpholin-4-yl-8-phenylchromen-4-one, another PI3K inhibitor, and an Akt inhibitor (Calbiochem 124005) showed similar protective effects. IRHC immunostaining and confocal microscopy analysis revealed that endocytic internalization of Bsep and Mrp2 induced by E217G was extensively prevented by WM; this effect was fully blocked by the microtubule-disrupting agent colchicine. The protection of WM was additive to that afforded by the classical protein kinase C (cPKC) inhibitor 5,6,7,13-tetrahydro-13-methyl-5-oxo-12

H

-indolo[2,3-
a

]pyrrolo[3,4-
c

]carbazole-12-propanenitrile (Gö6976); this suggested differential and complementary involvement of the PI3K and cPKC signaling pathways in E217G-induced cholestasis. In isolated perfused rat liver, an intraportal injection of E217G triggered endocytosis of Bsep and Mrp2, and this was accompanied by a sustained decrease in the bile flow and the biliary excretion of the Bsep and Mrp2 substrates [3H]taurocholate and glutathione until the end of the perfusion period. Unlike Gö6976, WM did not prevent the initial decay, but it greatly accelerated the recovery to normality of these parameters and the reinsertion of Bsep and Mrp2 into the canalicular membrane in a microtubule-dependent manner.

Conclusion:

The PI3K/Akt signaling pathway is involved in the biliary secretory failure induced by E217G through sustained internalization of canalicular transporters endocytosed via cPKC. (Hepatology 2010)
The Oncogenic Effect of Sulfatase 2 in Human Hepatocellular Carcinoma Is Mediated in Part by Glypican 3–Dependent Wnt Activation
Authors: Lai Jin-Ping , Oseini Abdul M. , Moser Catherine D. , Yu Chunrong , Elsawa Sherine F. , Hu Chunling , Nakamura Ikuo , Han Tao , Aderca Ileana , Isomoto Hajime , Garrity-Park Megan M. , Shire Abdirashid M. , Li Jia , Sanderson Schuyler O. , Adjei Alex A. , Fernandez-Zapico Martin E. , Roberts Lewis R.
Published: July 2010

Heparan sulfate proteoglycans (HSPGs) act as coreceptors or storage sites for growth factors and cytokines such as fibroblast growth factor and Wnts. Glypican 3 (GPC3) is the most highly expressed HSPG in hepatocellular carcinoma (HCC). Sulfatase 2 (SULF2), an enzyme with 6-O-desulfatase activity on HSPGs, is up-regulated in 60% of primary HCCs and is associated with a worse prognosis. We have previously shown that the oncogenic effect of SULF2 in HCC may be mediated in part through up-regulation of GPC3. Here we demonstrate that GPC3 stimulates the Wnt/β-catenin pathway and mediates the oncogenic function of SULF2 in HCC. Wnt signaling

in vitro

and

in vivo

was assessed in SULF2-negative Hep3B HCC cells transfected with SULF2 and in SULF2-expressing Huh7 cells transfected with short hairpin RNA targeting SULF2. The interaction between GPC3, SULF2, and Wnt3a was assessed by coimmunoprecipitation and flow cytometry. β-catenin–dependent transcriptional activity was assessed with the TOPFLASH (T cell factor reporter plasmid) luciferase assay. In HCC cells, SULF2 increased cell surface GPC3 and Wnt3a expression, stabilized β-catenin, and activated T cell factor transcription factor activity and expression of the Wnt/β-catenin target gene cyclin D1. Opposite effects were observed in SULF2-knockdown models.

In vivo

, nude mouse xenografts established from SULF2-transfected Hep3B cells showed enhanced GPC3, Wnt3a, and β-catenin levels.

Conclusion:

Together, these findings identify a novel mechanism mediating the oncogenic function of SULF2 in HCC that includes GPC3-mediated activation of Wnt signaling via the Wnt3a/glycogen synthase kinase 3 beta axis. (Hepatology 2010;)