bluuebunny/crossref_metadata_2025 huggingface dataset:
Designing Photobioreactors based on Living Cells Immobilized in Silica Gel for Carbon Dioxide Mitigation
Authors: Rooke Joanna C. , Léonard Alexandre , Meunier Christophe F. , Su Bao‐Lian
Published: July 2011

Atmospheric carbon dioxide levels have been rising since the industrial revolution, with the most dramatic increase occurring since the end of World War II. Carbon dioxide is widely regarded as one of the major factors contributing to the greenhouse effect, which is of major concern in today’s society because it leads to global warming. Photosynthesis is Nature’s tool for combating elevated carbon dioxide levels. In essence, photosynthesis allows a cell to harvest solar energy and convert it into chemical energy through the assimilation of carbon dioxide and water. Therefore photosynthesis is regarded as an ideal way to harness the abundance of solar energy that reaches Earth and convert anthropologically generated carbon dioxide into useful carbohydrates, providing a much more sustainable energy source. This Minireview aims to tackle the idea of immobilizing photosynthetic unicellular organisms within inert silica frameworks, providing protection both to the fragile cells and to the external ecosystem, and to use this resultant living hybrid material in a photobioreactor. The viability and activity of various unicellular organisms are summarized alongside design issues of a photobioreactor based on living hybrid materials.
Numerical Study of Heat Capacity in Dissipative Two‐Dimensional Yukawa Systems
Authors: Vaulina O. S. , Khrustalyov Yu. V. , Petrov O. F.
Published: July 2011

The problems associated with the physical properties of non‐ideal dissipative systems are of significant interest in various fields of science and technology (plasma physics, medical industry, physics of polymers, etc.). The best‐known model for description of pair interaction of repelling particles in physical kinetics is based on the screened potential of Yukawa type. In this paper we present the results of the study of the heat capacity in non‐ideal dissipative two‐dimensional Yukawa systems. The parameters responsible for the heat capacity are determined and investigated. Comparison of obtained coefficients of heat capacity with the existing theoretical model was performed (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Triage of cervical cytological diagnoses of atypical squamous cells by DNA methylation of paired boxed gene 1 (PAX1)
Authors: Chao Tai‐Kuang , Ke Feng‐Yi , Liao Yu‐Ping , Wang Hui‐Chen , Yu Cheng‐Ping , Lai Hung‐Cheng
Published: June 2011

Detection of cervical high‐grade squamous intraepithelial lesions (HSIL) in patients with equivocal cytological abnormalities, such as atypical squamous cells (ASC) of undetermined significance (ASCUS) or inability to exclude high‐grade squamous intraepithelial lesions (ASC‐H) is still a challenge. This study tested the efficacy of PAX1 methylation analysis in the triage of cervical ASCUS and ASC‐H and compared its performance with Hybrid Capture 2 (HC2) HPV test. A hospital‐based case–control study was conducted. Cervical scrapings from patients with ASCUS or ASC‐H were used for the quantitative methylation analysis of PAX1 methylation by MethyLight and HPV testing by HC2. Patients with ASC‐H or ASCUS with repeated abnormal smears underwent colposcopic biopsy and subsequent therapies. Diagnoses were made by histopathology at a follow‐up of 2 years. The efficacies of detecting high‐grade lesions were compared. Fifty‐eight cervical scrapings with cytological diagnosis of ASCUS (n = 41) and ASC‐H (n = 17) were analyzed. One of the 41 (2.4%) ASCUS patients and seven of 17 (41.2%) ASC‐H patients were confirmed to have HSIL. After dichotomy of the PMR, PAX1 methylation rates were significantly higher in ASC developing HSIL compared with those developing reactive atypia (87.5% vs. 12.5%, P < 0.001). Testing PAX1 methylation in cervical swabs of patients with ASC confers better sensitivity (87.5% vs. 62.5%) and specificity (98.0% vs. 86.0%) than HC2 HPV testing. We show for the first time that PAX1 hypermethylation analysis may be a better choice than HC2 in the triage of ASCUS and ASC‐H. Diagn. Cytopathol. 2013. © 2011 Wiley Periodicals, Inc.
Regulation of axonal outgrowth and pathfinding by integrin–ecm interactions
Authors: Myers, Jonathan P. , Santiago‐Medina Miguel , Gomez Timothy M.
Published: June 2011

Developing neurons use a combination of guidance cues to assemble a functional neural network. A variety of proteins immobilized within the extracellular matrix (ECM) provide specific binding sites for integrin receptors on neurons. Integrin receptors on growth cones associate with a number of cytosolic adaptor and signaling proteins that regulate cytoskeletal dynamics and cell adhesion. Recent evidence suggests that soluble growth factors and classic axon guidance cues may direct axon pathfinding by controlling integrin‐based adhesion. Moreover, because classic axon guidance cues themselves are immobilized within the ECM and integrins modulate cellular responses to many axon guidance cues, interactions between activated receptors modulate cell signals and adhesion. Ultimately, growth cones control axon outgrowth and pathfinding behaviors by integrating distinct biochemical signals to promote the proper assembly of the nervous system. In this review, we discuss our current understanding how ECM proteins and their associated integrin receptors control neural network formation. © 2011 Wiley Periodicals, Inc. Develop Neurobiol 71: 901‐923, 2011
Immunogenic cell death of human ovarian cancer cells induced by cytosolic poly(I:C) leads to myeloid cell maturation and activates NK cells
Authors: Kübler Kirsten , tho Pesch Carola , Gehrke Nadine , Riemann Soheila , Daßler Juliane , Coch Christoph , Landsberg Jennifer , Wimmenauer Vera , Pölcher Martin , Rudlowski Christian , Tüting Thomas , Kuhn Walther , Hartmann Gunther , Barchet Winfried
Published: July 2011

Owing to high rates of tumor relapse, ovarian cancer remains a fatal disease for which new therapeutic approaches are urgently needed. Accumulating evidence indicates that immune stimulation may delay or even prevent disease recurrence in ovarian cancer. In order to elicit proinflammatory signals that induce or amplify antitumor immune reactivity, we mimicked viral infection in ascites‐derived ovarian cancer cells. By transfection or electroporation we targeted the synthetic double‐stranded RNA poly(I:C) intracellularly in order to activate melanoma differentiation‐associated gene‐5 (MDA‐5), a sensor of viral RNA in the cytosol of somatic cells. Cancer cells reacted with enhanced expression of HLA‐class I, release of CXCL10, IL‐6, and type I IFN as well as tumor cell apoptosis. Monocytes and monocyte‐derived DCs (MoDCs) engulfed MDA‐5‐activated cancer cells, and subsequently upregulated HLA‐class I/II and costimulatory molecules, and secreted CXCL10 and IFN‐α. Further, this proinflammatory milieu promoted cytolytic activity and IFN‐γ secretion of NK cells. Thus, our data suggest that the engagement of MDA‐5 in a whole tumor cell vaccine is a promising approach for the immunotherapy of ovarian cancer.
CLEC‐2 signaling via Syk in myeloid cells can regulate inflammatory responses
Authors: Mourão‐Sá Diego , Robinson Matthew J. , Zelenay Santiago , Sancho David , Chakravarty Probir , Larsen Rasmus , Plantinga Maud , Van Rooijen Nico , Soares Miguel P. , Lambrecht Bart , Reis e Sousa Caetano
Published: July 2011

Myeloid cells express a plethora of C‐type lectin receptors (CLRs) that can regulate immune responses. CLEC‐2 belongs to the Dectin‐1 sub‐family of CLRs that possess an extracellular C‐type lectin‐like domain and a single intracellular hemITAM motif. CLEC‐2 is highly expressed on mouse and human platelets where it signals via Syk to promote aggregation. We generated a monoclonal antibody (mAb) against mouse CLEC‐2 and found that CLEC‐2 is additionally widely expressed on leukocytes and that its expression is upregulated during inflammation. MAb‐mediated crosslinking of CLEC‐2 leads to hemITAM‐dependent signaling via Syk, Ca2+ and NFAT and, in myeloid cells, modulates the effect of toll‐like receptor (TLR) agonists to selectively potentiate production of IL‐10. A macrophage/dendritic cell‐dependent increase in IL‐10 is also observed in mice given anti‐CLEC‐2 mAb together with LPS. Collectively, these data indicate that CLEC‐2 is expressed in myeloid cells and acts as a Syk‐coupled CLR able to modulate TLR signaling and inflammatory responses.
29Si NMR Shielding Calculations Employing Density Functional Theory, Focussing on Hypervalent Silicon Compounds
Authors: Du Van An , Stipicic Gregor N. , Schubert Ulrich
Published: July 2011

29Si NMR chemical shifts of 41 silicon‐containing compounds (14 tetra‐, 10 penta‐ and 17 hexacoordinate compounds) were calculated by employing DFT using the gauge including atomic orbital (GIAO) formalism and compared to experimental values. The hybrid B3LYP functional, the generalized gradient approximation functional (GGA) BPW91 and the meta‐GGA functional HCTH407 were used in conjunction with the 6‐31G(d,p) and 6‐311+G(2d) basis sets and a locally dense basis set [6‐311G+(2d) on Si and 6‐31G(d,p) on all other atoms]. The HCTH407/6‐311+G(2d) level of theory consistently performed best with a mean average error (MAE) of 5.9 ppm between calculated and experimental chemical shifts over the entire test set (4.4, 5.7 and 7.9 ppm for tetra‐, penta‐ and hexacoordinate compounds, respectively). The choice of a suitable basis set had a much larger influence on the accuracy of the results than the choice of functional. Additional calculations for some outliers with the 6‐311++G(2df,2pd) basis set yielded only small improvements, whereas the economically attractive, locally dense basis set (LDBS) yielded an MAE of 6.5 ppm with the HCTH407 functional over the entire test set after correction of systematic errors. For a subset of compounds, GIAO‐HF and MP2 ab initio calculations were performed yielding more accurate results than the DFT calculations (MAEs for HF, MP2 and HCTH407 were 3.9, 4.6 and 5.6 ppm, respectively) but required roughly two orders of magnitude more CPU time.
Functionalized Fulgides and Fluorophore‐Photoswitch Conjugates
Authors: Strübe Frank , Rath Susann , Mattay Jochen
Published: June 2011

Various fulgides based on benzofuryl and indolyl core units with versatile functionalities were synthesized. Substitution at the phenylic site shows only small effects on the photochromic properties compared to the parent compounds 30 and 31. Fulgide–dye conjugates were prepared based on anthryl and coumaryl moieties. Fluorophores were introduced to the fulgide via substitution reaction or copper‐catalyzed azide‐alkyne cycloaddition (CuAAC). The synthesized conjugates show weak fluorescence and quenching properties in solution.
Synthetic Studies on Dragmacidin D: Synthesis and Assembly of Three Fragments Towards an Advanced Intermediate
Authors: Oikawa Masato , Ikoma Minoru , Sasaki Makoto
Published: June 2011

We report herein the approach to the key advanced intermediate in the synthesis of the bioactive marine natural product dragmacidin D. By employing a modular synthesis strategy of three fragments (5, 7, and 8), the advanced intermediate 3 has been successfully synthesized in 2.5 % yield over 15 steps by starting from nitrotoluene 20. The synthesis also involves sequential cross‐coupling reactions, namely Sonogashira and Suzuki–Miyaura reactions, so that various analogues can be efficiently synthesized, which will allow the study of structure–activity relationships of dragmacidin D.
Discrimination and subjective well‐being: The moderating roles of identification with the heritage group and the host majority group
Authors: Schaafsma Juliette
Published: June 2011

This study examined the roles that identification with the heritage group and identification with the majority group play in the relationship between discrimination (subtle or blatant) and subjective well‐being among ethnic minority group members. Participants were 320 ethnic Turks and Moroccans in the Netherlands who completed a questionnaire that measured their well‐being, their perceptions of subtle and blatant discrimination, and their heritage group and majority group identification. The analyses found that relationships between discrimination and well‐being varied as a joint function of the source and strength of people's ethnic identification. Individuals who identified more strongly with their heritage group were more likely to report discrimination than low identifiers but were less likely to be negatively affected by it. For those who identified strongly with their heritage group, experiences with subtle and blatant discrimination and well‐being were unrelated, whereas for those who identified weakly with their heritage group, discrimination and well‐being were negatively related. In contrast, individuals who identified more strongly with the majority group were less likely to report discrimination than low identifiers but were more likely to be negatively affected by it. For those who identified strongly with the majority group, discrimination and well‐being were negatively related, whereas for those who identified weakly with the majority group, discrimination and well‐being were unrelated. These results suggest that although identifying strongly with the heritage group may buffer ethnic minorities from the negative effects of discrimination, identifying strongly with the majority group may exacerbate these effects. Copyright © 2011 John Wiley & Sons, Ltd.
Lactic acid production with Lactobacillus casei ssp. rhamnosus NBIMCC 1013: Modeling and optimization of the nutrient medium
Authors: Kostov George , Angelov Mihail , Denkova Zapryana , Dobrev Iliyan , Goranov Bogdan
Published: June 2011

The medium needed to perform a fermentation process with viable cells of Lactobacillus casei ssp. rhamnosus NBIMCC 1013 for the production of lactic acid was modeled and optimized. On the basis of single‐factor experiments and statistical analysis, the significant factors affecting the fermentation process, i.e. the concentration of carbon source, concentrations of both yeast and meat extracts, and the range of variability of these components were determined. Modeling and optimization of the medium contents were performed using central composite design. The composition of the medium used for the production of lactic acid (g/L) was as follows: glucose 69.8, meat extract 17.07, yeast extract 10.9, CH3COONa 10, K2HPO4 0.25, KH2PO4 0.25, MgSO4·7H2O 0.05, and FeSO4 0.05. The maximum specific growth rate of the lactic acid bacteria (μ=0.51 h−1) and other kinetic parameters were determined during cultivation in a laboratory bioreactor using the logistic equation and the Luedeking–Piret model. The obtained medium allows the production of lactic acid under optimum conditions, at high specific sugar assimilation rates and high lactic acid accumulation rates. The positive results of the paper are the new nutrient medium for lactic acid production and the process kinetic model, enabling scaling up and switching to a continuous process.
Engineering characteristics of a single‐use stirred bioreactor at bench‐scale: The Mobius CellReady 3L bioreactor as a case study
Authors: Kaiser Stephan C. , Eibl Regine , Eibl Dieter
Published: June 2011

Stirred single‐use bioreactors can be used as substitutes for their conventional counterparts made of glass or stainless steel in the development and production of biopharmaceuticals wherever possible. Various studies have confirmed their comparability in cell growth as well as in product quantity and quality. However, information about their engineering characteristics is still rare. This study focuses on the stirred Mobius® CellReady 3L bioreactor. The main engineering parameters for typical operation conditions used in animal cell cultivations are presented for the first time. Numerical simulations with a commercial CFD package (Fluent 6.3) were accomplished to obtain data on the single‐ and multi‐phase fluid flow, power input, mixing time and oxygen mass transfer. The results, which were compared with data from experiments and from the literature, reveal the suitability of the Mobius® CellReady 3L bioreactor for cell expansion and protein production with animal cell cultures. Furthermore, the data enable comparisons with other single‐use and reusable cell culture bioreactors at bench‐scale.
In vitro evaluation of the genotoxic and cytotoxic effects of artesunate, an antimalarial drug, in human lymphocytes
Authors: Mota Tatiane C. , Cardoso Plínio C. S. , Gomes Lorena M. , Vieira Priscilla C. M. , Corrêa Regianne M. S. , Santana Priscila Di Paula B. , Miranda Moysés S. , Burbano Rommel M. R. , Bahia Marcelo O.
Published: July 2011

Artesunate is one of the main antimalarial drugs used in several countries. It is a semisynthetic compound derived from artemisinin, a substance extracted from the Chinese plant, Artemisia annua L. Despite the widespread use of artesunate as an antimalarial drug, there is a lack of data regarding its genotoxic effects in human lymphocytes. Therefore, in this study, we used the comet assay and micronucleus test to evaluate the possible genotoxic effects of artesunate in cultured human lymphocytes. In addition, cell death by necrosis and apoptosis was also assessed. Cells exposed to different concentrations of artesunate showed a significant concentration‐dependent increase (P < 0.05) in DNA damage index and micronuclei frequency. A significant increase in the frequency of apoptotic and necrotic cells was also observed. Our results showed that artesunate is a genotoxic and cytotoxic compound in cultured human lymphocytes. Environ. Mol. Mutagen., 2011. © 2011 Wiley‐Liss, Inc.
A macro‐element model for non‐linear soil–shallow foundation–structure interaction under seismic loads: theoretical development and experimental validation on large scale tests
Authors: Figini R. , Paolucci R. , Chatzigogos C.T.
Published: June 2011

In this paper, different formulations of a macro‐element model for non‐linear dynamic soil‐structure interaction analyses of structures lying on shallow foundations are first reviewed, and secondly, a novel formulation is introduced, which combines some of the characteristics of previous approaches with several additional features. This macro‐element allows one to model soil‐footing geometric (uplift) and material (soil plasticity) non‐linearities that are coupled through a stiffness degradation model. Footing uplift is introduced by a simple non‐linear elastic model based on the concept of effective foundation width, whereas soil plasticity is treated by means of a bounding surface approach in which a vertical load mapping rule is implemented. This mapping is particularly suited for the seismic loading case for which the proposed model has been conceived. The new macro‐element is subsequently validated using cyclic and dynamic large‐scale laboratory tests of shallow foundations on dense sand, namely: the TRISEE cyclic tests, the Public Works Research Institute and CAMUS IV shaking table tests. Based on this comprehensive validation process against a set of independent experimental results, a unique set of macro‐element parameters for shallow foundations on dense sand is proposed, which can be used to perform predictive analyses by means of the present model. Copyright © 2011 John Wiley & Sons, Ltd.
An efficient performance‐based seismic design method for reinforced concrete frames
Authors: Hajirasouliha Iman , Asadi Payam , Pilakoutas Kypros
Published: June 2011

In this paper, a practical method is developed for performance‐based design of RC structures subjected to seismic excitations. More efficient design is obtained by redistributing material from strong to weak parts of a structure until a state of uniform deformation or damage prevails. By applying the design algorithm on 5, 10 and 15‐storey RC frames, the efficiency of the proposed method is initially demonstrated for specific synthetic and real seismic excitations. The results indicate that, for similar structural weight, designed structures experience up to 30% less global damage compared with code‐based design frames. The method is then developed to consider multiple performance objectives and deal with seismic design of RC structures for a design spectrum. The results show that the proposed method is very efficient at controlling performance parameters and improving structural behaviour of RC frames. Copyright © 2011 John Wiley & Sons, Ltd.
Mobility and contamination assessment of mercury in coal fly ash, atmospheric deposition, and soil collected from Tianjin, China
Authors: Wei Zheng , Wu Guanghong , Su Ruixian , Li Congwei , Liang Peiyu
Published: June 2011

Samples of class F coal fly ash (levels I, II, and III), slag, coal, atmospheric deposition, and soils collected from Tianjin, China, were analyzed using U.S. Environmental Protection Agency (U.S. EPA) Method 3052 and a sequential extraction procedure, to investigate the pollution status and mobility of Hg. The results showed that total mercury (HgT) concentrations were higher in level I fly ash (0.304 µg/g) than in level II and level III fly ash and slag (0.142, 0.147, and 0.052 µg/g, respectively). Total Hg in the atmospheric deposition was higher during the heating season (0.264 µg/g) than the nonheating season (0.135 µg/g). Total Hg contents were higher in suburban area soils than in rural and agricultural areas. High HgT concentrations in suburban area soils may be a result of the deposition of Hg associated with particles emitted from coal-fired power plants. Mercury in fly ash primarily existed as elemental Hg, which accounted for 90.1, 85.3, and 90.6% of HgT in levels I, II, and III fly ash, respectively. Mercury in the deposition existed primarily as sulfide Hg, which accounted for 73.8% (heating season) and 74.1% (nonheating season) of HgT. However, Hg in soils existed primarily as sulfide Hg, organo-chelated Hg and elemental Hg, which accounted for 37.8 to 50.0%, 31.7 to 41.8%, and 13.0 to 23.9% of HgT, respectively. The percentage of elemental Hg in HgT occurred in the order fly ash > atmospheric deposition > soils, whereas organo-chelated Hg and sulfide Hg occurred in the opposite order. The present approach can provide a window for understanding and tracing the source of Hg in the environment in Tianjin and the risk associated with Hg bioaccessibility. Environ. Toxicol. Chem. 2011;30:1997–2003. © 2011 SETAC
Critical load analysis in hazard assessment of metals using a Unit World Model
Authors: Gandhi Nilima , Bhavsar Satyendra P , Diamond Miriam L
Published: June 2011

A Unit World approach has been used extensively to rank chemicals for their hazards and to understand differences in chemical behavior. Whereas the fate and effects of an organic chemical in a Unit World Model (UWM) analysis vary systematically according to one variable (fraction of organic carbon), and the chemicals have a singular ranking regardless of environmental characteristics, metals can change their hazard ranking according to freshwater chemistry, notably pH and dissolved organic carbon (DOC). Consequently, developing a UWM approach for metals requires selecting a series of representative freshwater chemistries, based on an understanding of the sensitivity of model results to this chemistry. Here we analyze results from a UWM for metals with the goal of informing the selection of appropriate freshwater chemistries for a UWM. The UWM loosely couples the biotic ligand model (BLM) to a geochemical speciation model (Windermere Humic Adsorption Model [WHAM]) and then to the multi-species fate transport-speciation (Transpec) model. The UWM is applied to estimate the critical load (CL) of cationic metals Cd, Cu, Ni, Pb, and Zn, using three lake chemistries that vary in trophic status, pH, and other parameters. The model results indicated a difference of four orders of magnitude in particle-to-total dissolved partitioning (Kd) that translated into minimal differences in fate because of the short water residence time used. However, a maximum 300-fold difference was calculated in Cu toxicity among the three chemistries and three aquatic organisms. Critical loads were lowest (greatest hazard) in the oligotrophic water chemistry and highest (least hazard) in the eutrophic water chemistry, despite the highest fraction of free metal ion as a function of total metal occurring in the mesotrophic system, where toxicity was ameliorated by competing cations. Water hardness, DOC, and pH had the greatest influence on CL, because of the influence of these factors on aquatic toxicity. Environ. Toxicol. Chem. 2011;30:2157–2166. © 2011 SETAC
Aquatic to terrestrial transfer of sediment associated persistent organic pollutants is enhanced by bioamplification processes
Authors: Daley Jennifer M , Corkum Lynda D , Drouillard Ken G
Published: June 2011

Ephemeral emergent insects, such as mayflies (Hexagenia spp.), are commonly used as biomonitors of persistent organic pollutants (POPs) and provide a vector for aquatic-terrestrial contaminant transfer. Mayflies bioaccumulate sediment-associated contaminants by bioconcentration and biomagnification during the aquatic stage and concentrate POP residues postemergence due to bioamplification, which occurs as a result of weight and lipid loss without contaminant loss. The present study quantified polychlorinated biphenyl (PCB) bioamplification in male and female emergent mayflies at three sites. Male mayflies used 36 to 68% of their lipids during emergence, with the exception of caged males that were prevented from flight. Females did not lose lipid content between pre-emergent nymph and emerged life stages. Mass balance indicated no PCB elimination between life stages. The mean PCB bioamplification factor, expressed as the ratio of lipid-equivalent PCB concentrations across life stages, was 2.05 ± 0.38 for male imagos/nymphs and 1.91 ± 0.18 for male imago/subimago life stages. For females, bioamplification factors were close to unity. Wildlife consumers of imago stages of emergent mayflies can potentially increase their total daily intake of PCBs by 36% depending on the sex-ratio composition of their diet relative to animals that feed predominantly on nymph or subimago stages during mass emergence events. Environ. Toxicol. Chem. 2011;30:2167–2174. © 2011 SETAC
Enzymatic correlates of energy status in wild yellow perch inhabiting clean and contaminated environments
Authors: Gauthier Charles , Campbell Peter G.C , Couture Patrice
Published: June 2011

Enzymes representing a variety of metabolic pathways were examined in yellow perch (Perca flavescens) collected from a metal-contaminated region (Rouyn-Noranda, Québec, Canada) to determine which were most closely related to fish condition factor, pyloric caeca weight, and visceral lipid accumulation, as well to seek a better understanding of the influence of metal contamination on the physiology and biometrics of perch. Compared to laboratory fish, wild perch were under important energy restrictions. The condition factor of wild fish was correlated with indicators of aerobic metabolism (citrate synthase, cytochrome C oxidase), protein anabolism (nucleoside diphosphokinase), and indicators of lipid accumulation (glucose-6-phosphate dehydrogenase, visceral lipid index). Pyloric caeca weights were well correlated with indicators of protein anabolism, but only when both seasons were examined together, possibly indicating a lag in the response of enzymes to changes in diet. The addition of contaminant stress to existing energy restrictions led to changes in the relationships between enzymes and biometrics, reducing the predictive power of the models for perch in contaminated lakes. The present study broadens our knowledge of the impact of metal contamination on energy accumulation and tissue metabolic capacities in wild perch. Environ. Toxicol. Chem. 2011;30:2148–2156. © 2011 SETAC
A linear solvation energy relationship model of organic chemical partitioning to dissolved organic carbon
Authors: Kipka Undine , Di Toro Dominic M
Published: June 2011

Predicting the association of contaminants with both particulate and dissolved organic matter is critical in determining the fate and bioavailability of chemicals in environmental risk assessment. To date, the association of a contaminant to particulate organic matter is considered in many multimedia transport models, but the effect of dissolved organic matter is typically ignored due to a lack of either reliable models or experimental data. The partition coefficient to dissolved organic carbon (KDOC) may be used to estimate the fraction of a contaminant that is associated with dissolved organic matter. Models relating KDOC to the octanol–water partition coefficient (KOW) have not been successful for many types of dissolved organic carbon in the environment. Instead, linear solvation energy relationships are proposed to model the association of chemicals with dissolved organic matter. However, more chemically diverse KDOC data are needed to produce a more robust model. For humic acid dissolved organic carbon, the linear solvation energy relationship predicts log KDOC with a root mean square error of 0.43. Environ. Toxicol. Chem. 2011;30:2023–2029. © 2011 SETAC
Seien wir wählerisch – gehen wir wählen!
Authors: Windbichler Christine
Published: July 2011

Countdown zur Onlinewahl der Fachkollegien der DFG: Mit dem „Parlament der Wissenschaft”︁ können sich die Wissenschaftlerinnen und Wissenschaftler in Deutschland selbst die beste Stimme geben – für mehr Qualität und Querdenken in der Forschung und ihrer Förderung
Experimental Investigations into Phosphoric Acid Adsorption on Platinum Catalysts in a High Temperature PEM Fuel Cell
Authors: Kamat A. , Herrmann M. , Ternes D. , Klein O. , Krewer U. , Scholl S.
Published: July 2011

Dynamic testing of a phosphoric acid‐based high temperature PEM fuel cell shows a peculiar phenomenon. A certain current loss is observed after temperature cycling at constant voltage. This loss is incidentally recovered by applying a cell voltage spike to open circuit voltage. Experimental investigations into temperature, cell voltage, and ageing effects show that this phenomenon might occur due to the orientation of the adsorbed phosphate species on the platinum catalyst surface. Along with some supporting literature and experimental results, a hypothesis is presented in order to explain this occurrence. Phosphoric acid adsorption hysteresis on platinum catalyst due to temperature cycling could cause the temporary cell current loss. Electrode potential‐dependent molecule symmetry of adsorbed phosphate ions could bring about the cell current recovery.
Genomic aberrations in pediatric gliomas and embryonal tumors
Authors: Dahlback Hanne‐Sofie S. , Brandal Petter , Gorunova Ludmila , Widing Eva , Meling Torstein R. , Krossnes Bård K. , Heim Sverre
Published: June 2011

The pathogenesis of pediatric central nervous system tumors is poorly understood. To increase knowledge about the genetic mechanisms underlying these tumors, we performed genome‐wide screening of 17 pediatric gliomas and embryonal tumors combining G‐band karyotyping and array comparative genomic hybridization (aCGH). G‐banding revealed abnormal karyotypes in 56% of tumor samples (9 of 16; one failed in culture), whereas aCGH found copy number aberrations in all 13 tumors examined. Pilocytic astrocytomas (n = 3) showed normal karyotypes or nonrecurrent translocations by karyotyping but the well‐established recurrent gain of 7q34 and 19p13.3 by aCGH. Our series included one anaplastic oligoastrocytoma, a tumor type not previously characterized genomically in children, and one anaplastic neuroepithelial tumor (probably an oligoastrocytoma); both showed loss of chromosome 14 by G‐banding and structural aberrations of 6q and loss of 14q, 17p, and 22q by aCGH. Three of five supratentorial primitive neuroectodermal tumors showed aberrant karyotypes: two were near‐diploid with mainly structural changes and one was near‐triploid with several trisomies. aCGH confirmed these findings and revealed additional recurrent gains of 1q21‐44 and losses of 3p21, 3q26, and 8p23. We describe cytogenetically for the first time a cribriform neuroepithelial tumor, a recently identified variant of atypical teratoid/rhabdoid tumor with a favorable prognosis, which showed loss of 1p33, 4q13.2, 10p12.31, 10q11.22, and 22q by aCGH. This study indicates the existence of distinct cytogenetic patterns in pediatric gliomas and embryonal tumors; however, further studies of these rare tumors using a multimodal approach are required before their true genomic aberration pattern can be finally established. © 2011 Wiley‐Liss, Inc.
Dorsally‐derived oligodendrocytes in the spinal cord contribute to axonal myelination during development and remyelination following focal demyelination
Authors: Zhu Qiang , Whittemore Scott R. , Devries William H. , Zhao Xiaofeng , Kuypers Nicholas J. , Qiu Mengsheng
Published: June 2011

In the developing spinal cord, the majority of oligodendrocytes are derived from the ventral ventricular zone. Several recent studies suggested that a small number of oligodendrocyte precursor cells (OPCs) can also be generated in the dorsal spinal cord. However, it is not clear whether these dorsal oligodendrocyte precursor cells participate in myelination and remyelination. To investigate the fate and potential function of these dorsally‐derived oligodendrocytes (dOLs) in the adult spinal cord, Cre‐lox genetic fate mapping in transgenic mice was employed. We used the Pax3Cre knock‐in mouse to drive Cre expression in the entire dorsal epithelium and the Rosa26‐lacZ or Z/EG reporter line to trace their spatial distribution and population dynamics in the spinal cord. The dorsal OPCs generated from the Pax3‐expressing domains migrate into all regions of spinal cord and subsequently undergo terminal differentiation and axonal myelination. In response to a focal demyelination injury, a large number of newly differentiated oligodendrocytes originated from dOLs, suggesting that dOLs may provide an important source of OPCs for axonal remyelination in multiple sclerosis or spinal cord injury. © 2011 Wiley‐Liss, Inc.
Oncocytic carcinoma of the nasolacrimal duct treated by transnasal endoscopic resection
Authors: Villaret Andrea Bolzoni , Lombardi Davide , Schreiber Alberto , Farina Davide , Nicolai Piero
Published: June 2011

Background

Malignancies of the nasolacrimal apparatus are rare lesions that usually originate from the lacrimal sac. To the best of our knowledge, this is the first case of a primary oncocytic carcinoma of the nasolacrimal duct reported in the literature.

Methods

A 43‐year‐old woman presented with a 3‐month history of right epiphora. At nasal endoscopy, an exophytic lesion occupying the right inferior meatus was visible. Imaging studies showed an expansile lesion involving the nasolacrimal duct and the inferior meatus, but not invading the orbit or adjacent soft tissues. A biopsy was suggestive for an oncocytic lesion.

Results

A radical resection was obtained through an endoscopic extended medial maxillectomy with a definitive diagnosis of oncocytic carcinoma. Forty‐two months after surgery there was no evidence of disease.

Conclusions

In selected malignant lesions of the nasolacrimal duct not involving the adjacent soft tissues or lacrimal sac, an exclusive endoscopic approach can be considered. © 2011 Wiley Periodicals, Inc. Head Neck, 2013
Biomarkers of liver fibrosis: What lies beneath the receiver operating characteristic curve?
Authors: Guha Indra Neil , Myers Robert P. , Patel Keyur , Talwalkar Jayant A.
Published: July 2011

Noninvasive biomarkers of liver fibrosis represent an intense area of research with the goals of improving patient care, disease stratification, and aiding the development of future antifibrotic therapies. Despite the rapid progress in recent years, there remain questions about how diagnostic studies are designed, statistical methods to account for spectrum bias, clinically relevant thresholds of fibrosis that should be delineated, how diagnostics can be improved, and strengthening the reference test to judge emerging biomarkers. This review discusses the current methods to address these issues and where further progress is needed. (Hepatology 2011;)
PUMA–mediated apoptosis drives chemical hepatocarcinogenesis in mice
Authors: Qiu Wei , Wang Xinwei , Leibowitz Brian , Yang Wancai , Zhang Lin , Yu Jian
Published: July 2011

Hepatocyte death and proliferation contribute to hepatocellular carcinoma development after carcinogen exposure or chronic liver inflammation. However, the role and the molecular targets of hepatocyte death in relation to compensatory proliferation have not been fully characterized. In this study, we investigated the role of p53 up-regulated modulator of apoptosis (PUMA), a BH3-only protein important for both p53-dependent and -independent apoptosis, in a diethylnitrosamine (DEN)-induced liver carcinogenesis model.

PUMA

deficiency significantly decreased the multiplicity and size of liver tumors. DEN treatment induced p53-independent PUMA expression, PUMA-dependent hepatocyte death, and compensatory proliferation. Furthermore, inhibition or deletion of c-jun N-terminal kinase 1 (JNK1) abrogated PUMA induction, hepatocyte death, and compensatory proliferation.

Conclusion

: These results provide direct evidence that JNK1/PUMA-dependent apoptosis promotes chemical hepatocarcinogenesis through compensatory proliferation, and suggest apoptotic inducers as potential therapeutic targets in liver injury and cancer. (Hepatology 2011;54:1249–1258)
Modelling catchment‐scale water storage dynamics: reconciling dynamic storage with tracer‐inferred passive storage
Authors: Birkel Christian , Soulsby Chris , Tetzlaff Doerthe
Published: June 2011

We investigate the storage–discharge relationships of two nested (3·6 and 30·4 km2) upland catchments using rainfall–runoff models: (1) a nonlinear discharge sensitivity function and (2) a tracer‐constrained process‐based conceptual model. Both approaches explicitly acknowledge that water storage is neither time nor space invariant and this provided insight into the respective scaling relationships. Both modelling approaches consistently demonstrated small seasonal storage fluctuations consistent with the wet, cool Scottish climate: the smaller catchment exhibited a greater average dynamic storage (ca 55 mm) compared to the larger scale (ca 40 mm). However, there are differences in simulated storage quantities and ranges inferred from both models, which can largely be explained by model uncertainties and model assumptions. In contrast to the dynamic (active) storage indicated by the rainfall‐runoff models, input‐output relationships of δ18O in both catchments were used to estimate the passive storage available for mixing and tracer damping in streams. This showed that catchment storage is an order of magnitude greater (ranging from 500 to 900 mm) than the dynamic storage estimated by both models, though again, storage estimates were greater for the smaller catchment. The passive storage inferred for mixing indicates that discussion of dynamic storage revealed by water balance considerations masks a much larger catchment storage which may in turn determine sensitivity to environmental change. Copyright © 2011 John Wiley & Sons, Ltd.
High‐frequency storm event isotope sampling reveals time‐variant transit time distributions and influence of diurnal cycles
Authors: Birkel Christian , Soulsby Chris , Tetzlaff Doerthe , Dunn Sarah , Spezia Luigi
Published: June 2011

High‐frequency sampling of stable water isotopes in precipitation and stream water during winter and summer storm events was carried out in a 2·3 km2 lowland agricultural catchment. During peak flows of monitored events, the responses of δ2H and δ18O were comparable and inferred the dominance (ca 70%) of ‘old’ pre‐event water. Transit Time Distribution (TTD) inferred by a gamma function were fitted (Nash–Sutcliffe = 0·8) and were also similar for δ2H and δ18O. However, the shape (α) and scaling (β) parameters were markedly different for summer and winter events. Consequently, when antecedent wetness was high, mean transit times were in the order of days; when drier, they increased to months. Moreover, while the responses of δ2H and δ18O exhibited similar gradual recovery to pre‐event conditions during winter hydrograph recessions, they differed dramatically on summer recessions. Time series analysis showed that δ2H isotope content was correlated with the diurnal cycle of air temperature, suggesting an evaporative fractionation pattern which could be reproduced by a temperature‐based first‐order autoregressive model. The heavier δ18O isotope showed no evidence for such diurnal variability. The study highlights the utility of high‐frequency stable isotope sampling to explore the time‐variant nature of TTDs. Furthermore, it shows that the time of sampling in a diurnal cycle may have crucial significance for interpreting stream isotope signatures, particularly δ2H. Copyright © 2011 John Wiley & Sons, Ltd.
Protective effects of salecan against carbon tetrachloride‐induced acute liver injury in mice
Authors: Chen Peng , Wang Zhongqiu , Zeng Liyan , Wang Shiming , Dong Wei , Jia Aiqun , Cai Chun , Zhang Jianfa
Published: July 2011

Carbon tetrachloride (CCl4) is a well‐established model for screening hepato‐protective drugs. The aim of the present study was to evaluate the potential protective effects of a novel soluble β‐glucan salecan on acute liver injury induced by CCl4 in mice and to further explore the underlying mechanisms. Mice were given salecan (40 mg kg−1) or phosphate‐buffered saline for 3 days prior to treatment with a single intraperitoneal dose of CCl4 (1 ml kg−1 body weight). Animals were sacrificed at 0, 12, 24, 48, 72 and 96 h post‐injection of CCl4. Serum liver enzyme levels, histology, lipid peroxidation, glutathione (GSH) content, expression of antioxidant enzymes and hepatocyte proliferation were subsequently evaluated. The serum levels of hepatic enzyme markers were markedly reduced in the salecan pretreatment group compared with the control group. Histopathological examination of the livers revealed that hepatocellular degeneration and necrosis were significantly attenuated at an early stage during CCl4 intoxication and liver recovery was markedly accelerated at a later stage in salecan pre‐administered mice. Furthermore, salecan administration remarkably alleviated lipid peroxidation and restored GSH depletion. Meanwhile, the expression of antioxidant genes was significantly elevated in the salecan‐treated group. Interestingly, the administration of salecan remarkably enhanced hepatocyte proliferation in the recovery phase after CCl4 injection. Taken together, these results demonstrated that salecan exhibits a protective action on acute hepatic injury induced by CCl4 through attenuating oxidative stress and accelerating hepatocyte regeneration. Copyright © 2011 John Wiley & Sons, Ltd.
Founder's award to antonios G. Mikos, Ph.D., 2011 society for biomaterials annual meeting and exposition, Orlando, Florida, April 13–16, 2011
Authors: Kretlow James D. , Mikos Antonios G.
Published: June 2011

For biomaterials scientists focusing on tissue engineering applications, the gold standard material is healthy, autologous tissue. Ideal material properties and construct design parameters are thus both obvious and often times unachievable; additional considerations such as construct delivery and the underlying pathology necessitating new tissue yield additional design challenges with solutions that are not evident in nature. For the past nearly two decades, our laboratory and collaborators have aimed to develop both new biomaterials and a better understanding of the complex interplay between material and host tissue to facilitate bone and cartilage regeneration. Various approaches have ranged from mimicking native tissue material properties and architecture to developing systems for bioactive molecule delivery as soluble factors or bound directly to the biomaterial substrate. Such technologies have allowed others and us to design synthetic biomaterials incorporating increasing levels of complexity found in native tissues with promising advances made toward translational success. Recent work focuses on translation of these technologies in specific clinical situations through the use of adjunctive biomaterials designed to address existing pathologies or guide host‐material integration. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Isocyanate‐functional adhesives for biomedical applications. Biocompatibility and feasibility study for vascular closure applications
Authors: Hadba Ahmad R. , Belcheva Nadya , Jones Fatima , Abuzaina Ferass , Calabrese Allison , Kapiamba Mbiya , Skalla Walter , Taylor Jack L. , Rodeheaver George , Kennedy John
Published: June 2011

Biodegradable isocyanate‐functional adhesives based on poly(ethylene glycol)–adipic acid esters were synthesized, characterized, and evaluated in vitro and in vivo. Two types of formulations, P2TT and P2MT, were developed by functionalization with 2,4‐tolylene diisocyanate (TDI) or 4,4′‐methylene‐bis(phenyl isocyanate) (MDI), respectively, and branching with 1,1,1‐trimethylolpropane (TMP). The biocompatibility of the synthesized adhesive formulations was evaluated as per ISO 10993. Cytotoxicity, systemic toxicity, pyrogenicity, genotoxicity (reverse mutation of Salmonella typhimurium and Escherichia coli), hemolysis, intracutaneous reactivity, and delayed‐type hypersensitivity were evaluated. All formulations met the requirements of the conducted standard tests. The biological behavior and ability of the adhesive formulations to close an arteriotomy and withstand arterial pressure following partial approximation with a single suture were evaluated in a rat abdominal aorta model. Animals were evaluated at 1, 2, 3, and 4 weeks after surgery. Macroscopic and histopathologic evaluation of explanted arteries suggested that the P2TT formulation had better in vivo performance than the P2MT formulation. Additionally, the P2TT formulation resulted in less tissue reaction than P2MT formulation. To our knowledge, this is the first study demonstrating the potential of this new class of isocyanate‐functional degradable adhesives for vascular applications. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.