bluuebunny/crossref_metadata_2025 huggingface dataset:
A computer lab exploring evolutionary aspects of chromatin structure and dynamics for an undergraduate chromatin course*
Authors: Eirín‐López José M.
Published: February 2013

The study of chromatin constitutes one of the most active research fields in life sciences, being subject to constant revisions that continuously redefine the state of the art in its knowledge. As every other rapidly changing field, chromatin biology requires clear and straightforward educational strategies able to efficiently translate such a vast body of knowledge to the classroom. With this aim, the present work describes a multidisciplinary computer lab designed to introduce undergraduate students to the dynamic nature of chromatin, within the context of the one semester course “Chromatin: Structure, Function and Evolution.” This exercise is organized in three parts including (a) molecular evolutionary biology of histone families (using the H1 family as example), (b) histone structure and variation across different animal groups, and (c) effect of histone diversity on nucleosome structure and chromatin dynamics. By using freely available bioinformatic tools that can be run on common computers, the concept of chromatin dynamics is interactively illustrated from a comparative/evolutionary perspective. At the end of this computer lab, students are able to translate the bioinformatic information into a biochemical context in which the relevance of histone primary structure on chromatin dynamics is exposed. During the last 8 years this exercise has proven to be a powerful approach for teaching chromatin structure and dynamics, allowing students a higher degree of independence during the processes of learning and self‐assessment. © 2013 by The International Union of Biochemistry and Molecular Biology 41(2):95‐102, 2013.
Two‐dimensional nuclear magnetic resonance structure determination module for introductory biochemistry: synthesis and structural characterization of lyso‐glycerophospholipids
Authors: Garrett Teresa A. , Rose Rebecca L. , Bell Sidney M.
Published: February 2013

In this laboratory module, introductory biochemistry students are exposed to two‐dimensional 1H‐nuclear magnetic resonance of glycerophospholipids (GPLs). Working in groups of three, students enzymatically synthesized and purified a variety of 2‐acyl lyso GPLs. The structure of the 2‐acyl lyso GPL was verified using 1H‐correlation spectroscopy. Students scored significantly higher on an assessment of NMR knowledge after having participated in this lab module and in comparison to a similar cohort who did not participate. Inaddition, student confidence in their NMR knowledge and abilities increased 62% following the module and correlated with their ability to apply their NMR knowledge. Based on these results, the laboratory module was very effective at providing students with a more extensive understanding of the underlying concepts of NMR as a tool for structural determination. © 2013 by The International Union of Biochemistry and Molecular Biology 41(2):87‐94, 2013
In Situ Fabrication of Ag/Ag3PO4/Graphene Triple Heterostructure Visible‐Light Photocatalyst through Graphene‐Assisted Reduction Strategy
Authors: Jiang Baojiang , Wang Yanhui , Wang Jian‐Qiang , Tian Chungui , Li Wenjun , Feng Qingmao , Pan Qingjiang , Fu Honggang
Published: February 2013

The design and architecture of the nanoheterostructure composites was a key aim of material scientists owing to the central role of the composites in the improvement in photogenerated charge separation and quantum efficiency. The Ag/Ag3PO4/graphene triple heterostructure composites were fabricated in situ by the redox reaction between Ag+ and graphene. The structural evolution of these heterostructures was characterized by using XRD and TEM. The XPS and surface photovoltage spectroscopy revealed the photogenerated electron–hole pair’s transmission process within the composites. The Ag/Ag3PO4/graphene triple heterostructure could improve the charge separation rate under visible‐light irradiation. Simultaneously, the photocorrosion phenomenon can be inhibited effectively by the triple heterostructure, which leads to the high structural stability for photocatalysis. Graphene’s fine adsorption performance for O2 and organic pollutants is also an important factor in improving the photocatalytic efficiency. Thus, the novel Ag/Ag3PO4/graphene triple heterostructure demonstrates improved photocatalytic activity and structural stability under visible‐light irradiation. This facile and straightforward method has promising applications in the fabrication of different graphene‐based heterostructure photocatalyses.
Cyclopalladated Arylimine Self‐Assembly Films for Suzuki Reaction
Authors: Zhao Na , Li Tiesheng , Zhai Zhen , Qiu Jingjing , Xu Wenjian , Liu Hui , Wu Yangjie
Published: February 2013

A series of cyclopalladated arylimine self‐assembly films were prepared through chemical grafting to substrates and used to catalyze a Suzuki coupling reaction. Atomic force microscopy, water contact angle analysis, cyclic voltammetry, scanning electron microscopy, attenuated total‐reflectance infrared, and X‐ray photoelectron spectroscopy were used to analyze the morphology and composition of the heterogeneous catalysts. The results show that these cyclopalladated arylimine self‐assembly films immobilized on substrates could be used as efficient and reusable heterogeneous catalysts in the Suzuki reaction of aryl bromides under open air conditions in aqueous solution. These catalysts exhibited 10 times the catalytic performance of the homogeneous counterpart. The palladium catalysts were grafted onto the internal surface of the round‐bottomed flasks. The reaction flasks acted as both reaction vessels and catalysts, which simplified the reaction operations. The catalysts were run over 8 cycles without showing any sign of deactivation, suggesting the potential of the catalysts as advanced functional materials with applications in the heterogeneous catalysis of Suzuki reactions.
Hydrindacene‐Based Acetylenic Macrocycles with Horizontally and Vertically Ordered Functionality Arrays
Authors: Kawai Hidetoshi , Utamura Tatsuya , Motoi Erina , Takahashi Tomoko , Sugino Hiroyoshi , Tamura Manabu , Ohkita Masakazu , Fujiwara Kenshu , Saito Takao , Tsuji Takashi , Suzuki Takanori
Published: February 2013

The macrocyclization of 2,6‐diethynyl hydrindacenes (1) with functional groups at mutually perpendicular positions results in the formation of novel macrocycles which, as a result of the hindered rotation of the hydrindacene units, possess directionally persistent peripheral functionalities. The two hydrindacene units in the dimer macrocycle (2) have been shown to interact electronically through their respective butadiyne moieties, whereas the trimer macrocycle (3) demonstrates a moderate degree of geometrical flexibility as a result of the five‐membered hydrindacene rings. In addition, these trimer macrocycles contain a central cavity suitably sized for the inclusion of various solvent molecules. These new macrocycles can be further modified by introducing π‐conjugated side groups, such as styryl and thienyl groups, as well as by attaching a variety of peripheral ester groups.
Reactivity Studies of Iridium Pyridylidenes [TpMe2Ir(C6H5)2(C(CH)3C(R)NH] (R=H, Me, Ph)
Authors: Cristóbal Crispín , Hernández Yohar A. , López‐Serrano Joaquín , Paneque Margarita , Petronilho Ana , Poveda Manuel L. , Salazar Verónica , Vattier Florencia , Álvarez Eleuterio , Maya Celia , Carmona Ernesto
Published: February 2013

The reactivity of a series of iridiumpyridylidene complexes with the formula [TpMe2Ir(C6H5)2(C(CH)3C(R)NH] (1 a–1 c) towards a variety of substrates, from small molecules, such as H2, O2, carbon oxides, and formaldehyde, to alkenes and alkynes, is described. Most of the observed reactivity is best explained by invoking 16 e− unsaturated [TpMe2Ir(phenyl)(pyridyl)] intermediates, which behave as internal frustrated Lewis pairs (FLPs). H2 is heterolytically split to give hydridepyridylidene complexes, whilst CO, CO2, and H2CO provide carbonyl, carbonate, and alkoxide species, respectively. Ethylene and propene form five‐membered metallacycles with an IrCH2CH(R)N (R=H, Me) motif, whereas, in contrast, acetylene affords four‐membered iridacycles with the IrC(CH2)N moiety. C6H5(CO)H and C6H5CCH react with formation of IrC6H5 and IrCCPh bonds and the concomitant elimination of a molecule of pyridine and benzene, respectively. Finally the reactivity of compounds 1 a–1 c against O2 is described. Density functional theory calculations that provide theoretical support for these experimental observations are also reported.
A General Strategy Towards Encapsulation of Nanoparticles in Sandwiched Graphene Sheets and the Synergic Effect on Energy Storage
Authors: Wang Yu , Bai Yuanjuan , Li Xiao , Feng Yangyang , Zhang Huijuan
Published: February 2013

A novel and universal approach towards the unique encapsulation of nanoparticles in the sandwiched graphene sheets is presented here. In the method, a low‐cost, sustainable and environmentally friendly carbon source, glucose, is firstly applied to yield the high‐quality, uniform and coupled graphene sheets in a large scale, and the pre‐fabricated hydrated nanosheets act as the sacrificial templates to generate the enveloped metallic nanoparticles. After controllable oxidation or removal of the encapsulated nanoparticles, sandwiched nanocomposite with oxidizes nanoparticles encapsulated in graphene sheets or pure phase of sandwich‐like and coupled graphene sheets would be achieved. Moreover, the synergic effect on energy storage via Li‐ion batteries is solidly verified in the Co3O4@graphene nanocomposite. More importantly, the unique structure of the nanoparticles‐encapsulated sandwiched graphene sheets will definitely result in additional applications, such as biosensors, supercapacitors and specific catalyses. These results have enriched the family of graphene‐based materials and recognized some new graphene derivatives, which will be considerably meaningful in chemistry and materials sciences.
Investigation of Binary Diffusion Coefficients in Argon‐Neon Mixtures Using a Loschmidt Cell Combined with Holographic Interferometry
Authors: Kugler Tanja , Rausch Michael Heinrich , Fröba Andreas Paul
Published: February 2013

Für Argon/Neon‐Gemische wurden über den gesamten Zusammensetzungsbereich binäre Diffusionskoeffizienten Dij mittels einer Loschmidt‐Zelle bei 293,15 – 333,15 K und 1 – 10 bar bestimmt. Die beiden Halbzellen der Loschmidt‐Zelle wurden vor Beginn der Messungen mit den unterschiedlichen Reingasen befüllt. Nach Verbindung der beiden Halbzellen wurde die Veränderung der partiellen Moldichte bzw. des Brechungsindex als Funktion von Ort und Zeit mittels holografischer Interferometrie detektiert. Die hieraus erhaltenen Daten für Dij zeigen im Vergleich zu Literaturdaten in der oberen Halbzelle systematische Abweichungen. Für die entsprechenden Werte der unteren Halbzelle kann dagegen eine sehr gute Übereinstimmung mit der Literatur gefunden werden. Das Produkt aus molarer Mischungsdichte und Dij weist im Rahmen der Messunsicherheit keine signifikante Abhängigkeit vom Druck auf.
Seasonal Variation of Temperature, pH, and Dissolved Oxygen Concentration in Lake Rosu, Romania
Authors: Romanescu Gheorghe , Stoleriu Cristian C.
Published: February 2013

Lake Rosu (Red Lake) in the Hasmas (Curmaturii) Mountains was created by the natural barrage of the Bicaz River, a tributary of the Bistrita River, in 1837. Measurements in 2009 were performed, using the Hach Lange multi‐parameter meter, to determine physical and chemical parameters of water. Basic parameters for the analysis of the ecological conditions were assessed: temperature, dissolved oxygen and pH. Surface water temperature was 2–3°C lower in summer and higher in winter (except during the period of ice cover) compared with spring and autumn data. At depths <7 m, the temperature showed constant values of 4–6°C with nearly the same values in autumn and spring. pH values lied between 7 and 8 at the surface as well as in depth. During the summer, pH values decreased from 8 to 7 in the depth. In spring and autumn, the pH values remained constant and identical. The value of dissolved oxygen was good throughout the year. The surface reached values of 10 mg O2/L annually at depths >7–8 m with a limit of 0 mg O2/L. Lake Rosu becomes a mountain aquatorium which attracts many tourists. However, its degree of pollution is extremely low.
Association between exercise and primary incidence of prostate cancer
Authors: Singh Abhay A. , Jones Lee W. , Antonelli Jodi A. , Gerber Leah , Calloway Elizabeth E. , Shuler Kathleen H. , Freedland Stephen J. , Grant Delores J. , Hoyo Cathrine , Bañez Lionel L.
Published: February 2013

BACKGROUND:

Exercise is a modifiable lifestyle risk factor associated with prostate cancer risk reduction. However, whether this association is different as a function of race is unclear. In the current study, the authors attempted to characterize the link between exercise and prostate cancer (CaP) in white and black American men.

METHODS:

Using a prospective design, 307 men (164 of whom were white and 143 of whom were black) who were undergoing prostate biopsy completed a self‐reported survey that assessed exercise behavior (metabolic equivalent [MET] hours per week). Crude and adjusted logistic regression analyses were used to estimate the risk of prostate cancer controlling for age, body mass index, digital rectal examination findings, previous biopsy, Charlson comorbidity score, and family history of CaP stratified by self‐reported race.

RESULTS:

There was no significant difference noted with regard to the amount of exercise between racial groups (P = .12). Higher amounts of MET hours per week were associated with a decreased risk of CaP for white men in both crude (P = .02) and adjusted (P = .04) regression models. Among whites, men who exercised ≥ 9 MET hours per week were less likely to have a positive biopsy result compared with men exercising < 9 MET hours per week (odds ratio, 0.47; 95% confidence interval, 0.22‐0.99 [P = .047]). There was no association noted between MET hours per week and risk of CaP among black men in both crude (P = .79) and adjusted (P = .76) regression models.

CONCLUSIONS:

In a prospective cohort of men undergoing biopsy, increased exercise, measured as MET hours per week, was found to be associated with CaP risk reduction among white but not black men. Investigating race‐specific mechanisms by which exercise modifies CaP risk and why these mechanisms disfavor black men in particular are warranted. Cancer 2013. © 2013 American Cancer Society.
Influence of Composition on the Performance of Sintered Cu(In,Ga)Se2 Nanocrystal Thin‐Film Photovoltaic Devices
Authors: Akhavan Vahid A. , Harvey Taylor B. , Stolle C. Jackson , Ostrowski David P. , Glaz Micah S. , Goodfellow Brian W. , Panthani Matthew G. , Reid Dariya K. , Vanden Bout David A. , Korgel Brian A.
Published: February 2013

Thin‐film photovoltaic devices (PVs) were prepared by selenization using oleylamine‐capped Cu(In,Ga)Se2 (CIGS) nanocrystals sintered at a high temperature (>500 °C) under Se vapor. The device performance varied significantly with [Ga]/[In+Ga] content in the nanocrystals. The highest power conversion efficiency (PCE) observed in the devices studied was 5.1 % under air mass 1.5 global (AM 1.5 G) illumination, obtained with [Ga]/[In+Ga]=0.32. The variation in PCE with composition is partly a result of bandgap tuning and optimization, but the main influence of nanocrystal composition appeared to be on the quality of the sintered films. The [Cu]/[In+Ga] content was found to be strongly influenced by the [Ga]/[In+Ga] concentration, which appears to be correlated with the morphology of the sintered film. For this reason, only small changes in the [Ga]/[In+Ga] content resulted in significant variations in device efficiency.
Automated REcognition of Tissue‐associated Erythrocytes (ARETE)—a new tool in tissue cytometry
Authors: Heindl Andreas , Seewald Alexander K. , Thalhammer Theresia , Bises Giovanna , Schepelmann Martin , Uhrova Hana , Dekan Sabine , Mesteri Ildiko , Rogojanu Radu , Ellinger Isabella
Published: February 2013

Automated microscopic image analysis of immunofluorescence‐stained targets on tissue sections is challenged by autofluorescent elements such as erythrocytes, which might interfere with target segmentation and quantification. Therefore, we developed an automated system (Automated REcognition of Tissue‐associated Erythrocytes; ARETE) for in silico exclusion of erythrocytes. To detect erythrocytes in transmission images, a cascade of boosted decision trees of Haar‐like features was trained on 8,640/4,000 areas (15 × 15 pixels) with/without erythrocytes from images of placental sections (4 µm). Ground truth data were generated on 28 transmission images. At least two human experts labelled the area covered by erythrocytes. For validation, output masks of human experts and ARETE were compared pixel‐wise against a mask obtained from majority voting of human experts. F1 score, specificity, and Cohen's κ coefficients were calculated. To study the influence of erythrocyte‐derived autofluorescence, we investigated the expression levels of a protein (receptor for advanced glycated end products; RAGE) in placenta and number of Ki‐67‐positive/cytokeratin 8‐positive epithelial cells in colon sections. ARETE exhibited high sensitivity (99.87%) and specificity (99.81%) on a training‐subset and processed transmission images (1,392 × 1,024 pixels) within 4 sec. ARETE and human expert's F1‐scores were 0.55 versus 0.76, specificities 0.85 versus 0.92 and Cohen's κ coefficients 0.41 versus 0.68. A ranking of Cohen's κ coefficient by the scale of Fleiss certified “good agreement” between ARETE and the human experts. Applying ARETE, we demonstrated 4–14% false‐positive RAGE‐expression in placenta, and 18% falsely detected proliferative epithelial cells in colon, caused by erythrocyte‐autofluorescence. ARETE is a fast system for in silico reduction of erythrocytes, which improves automated image analysis in research and diagnostic pathology. © 2013 International Society for Advancement of Cytometry.
Implication of hepatic transporters (MDR1 and MRP2) in inflammation‐associated idiosyncratic drug‐induced hepatotoxicity investigated by microvolume cytometry
Authors: Saab Lea , Peluso Jean , Muller Christian D. , Ubeaud‐Sequier Genevieve
Published: February 2013

Idiosyncratic drug‐induced hepatotoxicity accounts for about 13% of all cases of acute liver failure, therefore cited as the most frequent reason for post‐marketing drug withdrawal. Despite this, the underlying mechanisms remain poorly understood due to lack in adequate screening assays and predictive in vitro models. Hepatic transporters play a crucial role in the absorption, distribution, and elimination of both endogenous substrates and xenobiotics. Defects in transporter function can lead to altered drug disposition, including toxicity and loss of efficacy. Inflammation is one condition for demonstrated variable drug response, attributed in part, to changes in function of drug transporters. The present study investigates the implication of two important hepatic transporters (MDR1 and MRP2) in idiosyncratic drug‐induced hepatotoxicity in the presence and absence of an inflammatory context. The synergistic effect of idiosyncratic drugs (Trovafloxacin, nimesulide, telithromycin, and nefazodone) and inflammatory stimuli (TNF‐α + LPS) on the efflux activity of hepatic transporters was studied using microvolume cytometry. Our results demonstrated on the one hand that both MDR1 and MRP2 are variably implicated in idiosyncratic drug‐induced liver injury and on the other hand that the occurrence of an inflammatory reaction during idiosyncratic drug therapy can noticeably modulate this implication. In the absence of an inflammatory stress, none of the four tested drugs modulated the efflux activity of MRP2; nevertheless telithromycin and nefazodone inhibited the efflux activity of MDR1. Upon occurrence of an inflammatory stress, the inhibitory potential of trovafloxacin, nimesulide, and nefazodone on the efflux activity of MRP2 was noticeably revealed, while the telithromycin and nefazodone‐induced inhibition of MDR1 was clearly attenuated. Knowledge of underlying mechanisms may significantly contribute to elimination of potential hepatotoxic drugs long before marketing and to prevention of drug‐induced hepatotoxicity. © 2013 International Society for Advancement of Cytometry
Sap flow changes in relation to permafrost degradation under increasing precipitation in an eastern Siberian larch forest
Authors: Iijima Yoshihiro , Ohta Takeshi , Kotani Ayumi , Fedorov Alexander N. , Kodama Yuji , Maximov Trofim C.
Published: February 2013

Continuous observation over the last decade has revealed evidence of abrupt land surface moistening as well as rapid soil warming within the active layer and upper part of permafrost within the central Lena River basin in eastern Siberia. The present study examined the relationship between permafrost degradation and ecohydrological change in this region. Increases in the depth of the active layer recorded since the winter of 2004 resulting from increases in moisture saturation within the soil have resulted in thawing the upper permafrost causing thermokarst subsidence, which has negatively impacted the growth of boreal (larch) forests in the region. According to multi‐year sap flow measurements taken between 2006 and 2009, transpiration from larch trees (Larix cajanderi Mayr.) was significantly reduced as a result of the region's concave micro‐topography, which, in conjunction with the deepening and moistening of the active layer, created perennially waterlogged conditions that left mature trees withered and dead. Several trees with reduced amounts of foliage showed a remarkable reduction in seasonal average canopy stomatal conductance during the 2009 growing season. The reduction ratio of canopy stomatal conductance within emergent trees of heights greater than 15 m between 2006 and 2009 had a significant positive correlation with the increase in thickness of the active layer over that same period. These findings indicated that wetting trends in a permafrost region caused by arctic climate change may lead to unexpected ecohydrological responses with respect to permafrost degradation in eastern Siberia. Copyright © 2013 John Wiley & Sons, Ltd.
The soluble isoform of CTLA‐4 as a regulator of T‐cell responses
Authors: Ward Frank J. , Dahal Lekh N. , Wijesekera Subadra K. , Abdul‐Jawad Sultan K. , Kaewarpai Taniya , Xu Heping , Vickers Mark A. , Barker Robert N.
Published: February 2013

CTLA‐4 is a crucial immune regulator that mediates both negative costimulation signals to T cells, and regulatory T (Treg)‐cell extrinsic control of effector responses. Here we present evidence supporting a novel mechanism for this extrinsic suppression, executed by the alternatively spliced soluble CTLA‐4 isoform (sCTLA‐4). Analyses of human T cells in vitro show that sCTLA‐4 secretion can be increased during responses, and has potent inhibitory properties, since isoform‐specific blockade of its activity significantly increased Ag‐driven proliferation and cytokine (IFN‐γ, IL‐17) secretion. Treg cells were demonstrated to be a prominent source of sCTLA‐4, which contributed to suppression in vitro when their numbers were limiting. The soluble isoform was also produced by, and inhibited, murine T cells responding to Ag in vitro, and blockade of its activity in vivo protected against metastatic spread of melanoma in mice. We conclude that sCTLA‐4 is an important immune regulator, responsible for at least some of the inhibitory effects previously ascribed to the membrane‐bound isoform. These results suggest that the immune system exploits the different CTLA‐4 isoforms for either intrinsic or extrinsic regulation of T‐cell activity.
High yield of monoacylglycerols production through low‐temperature chemical and enzymatic glycerolysis
Authors: Zhong Nanjing , Li Lin , Xu Xuebing , Cheong Ling‐Zhi , Xu Zhenbo , Li Bing
Published: February 2013

The present study aimed to produce MAG through low‐temperature chemical glycerolysis. Over 80% MAG yield with 97% TAG conversion was obtained within short reaction times at temperature of 35–55°C, when tert‐butanol (TB) or tert‐pentanol (TP) was used as reaction medium and sodium hydroxide (NaOH) as catalyst. TB gave a faster reaction rate than TP. Catalysts were important for the low‐temperature chemical glycerolysis reaction. Of the eight common base catalysts evaluated, only NaOH and potassium hydroxide (KOH) were effective, and NaOH was better than KOH. Reaction parameters were studied and optimized. The optimum conditions were TB dosage 3:1 (TB to oil in weight ratio), NaOH concentration 0.45 wt% based on oil, molar ratio of glycerol to oil 5:1. Under these conditions, similar MAG yield and TAG conversion was also observed by Novozym 435 catalyzed glycerolysis, however, a 4 h reaction was required.

Practical applications: The process of NaOH catalyzed chemical glycerolysis for MAG production in TB solvent system described in this study provides several advantages including short reaction time and high product yield, which is potential for industrial considerations.
COMPARING SORPTION BEHAVIOR OF PYRETHROIDS BETWEEN FORMULATED AND NATURAL SEDIMENTS
Authors: Cui Xinyi , Gan Jay
Published: February 2013

Formulated sediments are recommended for use in toxicity tests to achieve standardized evaluations. However, the organic matter used in formulated sediments may differ qualitatively from that in natural sediments, which may lead to different chemical partition patterns and, hence, different toxicity effects. By deriving partition coefficients for organic carbon and dissolved organic carbon (KOC and KDOC, respectively) for eight pyrethroid insecticides from three formulated and five natural sediments, the authors characterized the differences between formulated and natural sediments in pesticide sorption. For all pyrethroids, the mean values of KOC and KDOC of formulated sediments were two to three, and three to 10 times smaller than those of natural sediments, respectively. The two formulated sediments containing α-cellulose or Manitoba peat showed significantly (p < 0.0001) smaller KOC and KDOC values than natural sediments based on statistical analyses, while the difference was not significant for the formulated sediment containing New Brunswick peat. The KOC values were closely correlated (p < 0.001) with soot carbon content, while the amount of carboxylic or phenolic functional groups may have affected KDOC. Therefore, the source and quality of organic matter are likely the most important factors in formulated sediments and must be standardized to provide consistency in sediment toxicity tests. Environ. Toxicol. Chem. 2013;32:1033–1039. © 2013 SETAC
PLANT CONSUMPTION BY GRIZZLY BEARS REDUCES BIOMAGNIFICATION OF SALMON-DERIVED POLYCHLORINATED BIPHENYLS, POLYBROMINATED DIPHENYL ETHERS, AND ORGANOCHLORINE PESTICIDES
Authors: Christensen Jennie R. , Yunker Mark B. , MacDuffee Misty , Ross Peter S.
Published: February 2013

The present study characterizes the uptake and loss of persistent organic pollutants (POPs) in grizzly bears (Ursus arctos horribilis) by sampling and analyzing their terrestrial and marine foods and fecal material from a remote coastal watershed in British Columbia, Canada. The authors estimate that grizzly bears consume 341 to 1,120 µg of polychlorinated biphenyls (PCBs) and 3.9 to 33 µg of polybrominated diphenyl ethers daily in the fall when they have access to an abundant supply of returning salmon. The authors also estimate that POP elimination by grizzly bears through defecation is very low following salmon consumption (typically <2% of intake) but surprisingly high following plant consumption (>100% for PCBs and organochlorine pesticides). Excretion of individual POPs is largely driven by a combination of fugacity (differences between bear and food concentrations) and the digestibility of the food. The results of the present study are substantiated by a principal components analysis, which also demonstrates a strong role for log KOW in governing the excretion of different POPs in grizzly bears. Collectively, the present study's results reveal that grizzly bears experience a vegetation-associated drawdown of POPs previously acquired through the consumption of salmon, to such an extent that net biomagnification is reduced. Environ. Toxicol. Chem. 2013;32:995–1005. © 2013 SETAC
UPTAKE AND METABOLISM OF INDIVIDUAL POLYBROMINATED DIPHENYL ETHER CONGENERS BY EMBRYONIC ZEBRAFISH
Authors: Usenko Crystal Y. , Robinson Eleanor M. , Bruce Erica D. , Usenko Sascha
Published: February 2013

Embryonic zebrafish were used to compare the uptake and metabolism of six polybrominated diphenyl ether (PBDE) congeners (BDEs 28, 47, 99, 100, 153, and 183) and identified metabolites from static exposures at 24 and 120 h postfertilization (hpf). An inverse relationship was observed between uptake of PBDEs and their octanol–water partitioning coefficients (uptake of BDEs 28 and 47 > 99 and 100 > 153 and 183). Debromination metabolites were identified in all congeners (excluding BDE 28) tested in the 120-hpf tissue samples. Interestingly, BDE 153 underwent meta-debromination, forming BDEs 47 and 99. Gene transcription analysis was conducted at 120 hpf to identify potential metabolic pathways for the PBDEs examined in the present study (gstpi, deiodinases 1 and 2, cyp1a1, cyp1b1, and ugt5g). The greatest induction was of ugt5g for all congeners and deiodinase transcription was also upregulated by BDEs 28, 47, and 183. The cyp1a1 and cyp1b1 were upregulated by BDEs 28, 47, 99, and 183. The least alterations in gene transcription were in the BDE 153–exposed embryos. A clear primary pathway of debromination metabolism was not identified; however, upregulation of these different genes indicated that fish were responding to exposure of PBDEs. Furthermore, the present study demonstrated that the most bioavailable congeners are also those with the highest reported toxicity. Environ. Toxicol. Chem. 2013;32:1153–1160. © 2013 SETAC
EVALUATION OF THE TEST OF SIGNIFICANT TOXICITY FOR DETERMINING THE TOXICITY OF EFFLUENTS AND AMBIENT WATER SAMPLES
Authors: Diamond Jerry M. , Denton Debra L. , Roberts John W. , Zheng Lei
Published: February 2013

The test of significant toxicity (TST) is a hypothesis-testing approach based on bioequivalence developed by the U.S. Environmental Protection Agency (U.S. EPA) for analyzing whole-effluent toxicity (WET) and ambient toxicity data. The present study compares results of acute and chronic toxicity tests of effluent, storm-water, and ambient (i.e., receiving-water) samples using both the TST and the standard no-observed-effect concentration (NOEC) approach. Valid WET data were analyzed from 890 tests provided by more than 25 dischargers in California and Washington, USA, representing the majority of test methods used in the U.S. WET program. An additional 3,201 freshwater chronic toxicity tests, obtained from ambient monitoring programs in California, were also analyzed. The TST and NOEC approaches both declared a low number (<6.5%) of tests toxic if effects were below the unacceptable toxicity regulatory management decision (RMD) of 25% effect in chronic tests or 20% effect in acute tests. However, those test methods having generally lower within-test variability and greater test power (e.g., urchin fertilization test) had a much lower percentage of tests declared toxic than the NOEC approach when effects were below the unacceptable toxicity RMD. In addition, the TST showed fewer tests to be nontoxic than NOEC if the test exhibited effects greater than the toxicity RMD (0.1 and 9.6% for TST and NOEC, respectively, for effluents and 0 and 9.5%, respectively, for ambient samples). Our results demonstrate that the TST is more likely to identify a toxic sample when effects are fairly substantial (≥25% effect in chronic testing and ≥20% effect in acute tests) and less likely to identify a sample as toxic when effects are negligible (≤10% effect). Furthermore, these results demonstrate that appropriate WET data interpretation benefits from having well-designed test methods with sufficient power to identify significant toxicity or biologically insignificant effects when they occur. Environ. Toxicol. Chem. 2013;32:1101–1108. © 2013 SETAC
A universal, broad‐environment energy conversion signature of explosive cyclones
Authors: Black Mitchell Timothy , Pezza Alexandre Bernardes
Published: February 2013

This study presents the first analysis of the Lorenz energetics associated with a global climatology of explosive cyclones. Energy budgets of the large‐scale environment are calculated for 32 year climatologies (1980–2011) of explosive cyclones within four of the most active regions in the world: the Northwest Pacific, the North Atlantic, the Southwest Pacific, and the South Atlantic. A robust signature in the Lorenz energy cycle is observed; anomalous energy conversions commence 48 h before explosive cyclone development and remain strong (i.e., significantly above background noise) for 120 h. Remarkably, the calculated signature of energy conversion is virtually identical for all four geographical regions. While the conversions imply a classic baroclinic growth cycle, they are not seen in regular cyclones that undergo a deepening of less than half that exhibited by explosive cyclones. This finding opens a new avenue of exploration of explosive storm behavior based on the large‐scale environment.
Mid‐21st century chemical forcing of climate by the civil aviation sector
Authors: Unger Nadine , Zhao Yupu , Dang Hongyan
Published: February 2013

Strong growth in the civil aviation sector will accelerate in the future. Here, we confront the future net chemical (ozone, methane, sulfate, nitrate, black carbon, and water vapor) global climate impact of aviation at 2050 for three novel plausible scenarios constructed at the Volpe National Transportation Center using the U.S. Federal Aviation Administration (FAA) Aviation Environmental Design Tool (AEDT). The aviation net chemical climate impact is cooling in all cases and increases from −10 ± 4 mW m−2 in the contemporary climate up to –69 ± 21 mW m−2 by 2050. Future improvements in fuel efficiency provide the opportunity to reduce aviation's net chemical climate impact by ~50% relative to a baseline scenario of unconstrained growth. On the 20 year time horizon, the cooling net aviation chemical climate impact masks the aviation CO2 global warming by up to 50–100% in the contemporary and future atmospheres.
Sea surface drag and the role of spray
Authors: Richter David H. , Sullivan Peter P.
Published: February 2013

Motivated by the possible effects of spray on the drag felt by the ocean surface in high winds, we use direct numerical simulation coupled with Lagrangian particle tracking to investigate how suspended inertial particles alter momentum flux in an idealized turbulent flow. Turbulent Couette flow is used for this purpose since the momentum flux profile is constant across the domain height; a characteristic similar to the constant‐flux layer in the atmospheric surface layer. The simulations show that when inertial particles are introduced into a turbulent flow, they carry a portion of the total vertical momentum flux, and that this contribution can be significant when the particle concentration is sufficiently large. The numerical setup is also used to evaluate a dispersed phase model that treats spray effects as equivalent to an increase in stable atmospheric stratification. Our simulations suggest that in the range of droplet sizes typically found near the air‐sea interface, particle inertial effects dominate any particle‐induced stratification effects.
Contrail radiative forcing over the Northern Hemisphere from 2006 Aqua MODIS data
Authors: Spangenberg Douglas A. , Minnis Patrick , Bedka Sarah T. , Palikonda Rabindra , Duda David P. , Rose Fred G.
Published: February 2013

Radiative forcing due to linear‐shaped jet contrails is calculated over the Northern Hemisphere for four seasonal months using 2006 Aqua Moderate‐resolution Imaging Spectroradiometer cloud and contrail property retrieval data in a radiative transfer model. The 4 month mean shortwave, longwave, and net radiative forcings normalized to 100% contrail cover are −5.7, 14.2, and 8.5 Wm−2. Mean total net forcing over the northern half of the globe varies from 9.1 mW m−2 during October to 12.1 mW m−2 in January and is only representative at 01:30 and 13:30 LT in nonpolar regions. In some dense flight traffic corridors, the mean net forcing approaches 80 mW m−2. Scaling the 4 month average of 10.6 mW m−2 to the Southern Hemisphere air traffic yields global mean net forcing of 5.7 mW m−2, which is smaller than most model estimates. Nighttime net forcing is 3.6 times greater than during daytime, when net forcing is greatest over low clouds. Effects from contrail cirrus clouds that evolve from linear contrails are not considered in these results.
Scavenger receptor BI and ABCG5/G8 differentially impact biliary sterol secretion and reverse cholesterol transport in mice
Authors: Dikkers Arne , Freak de Boer Jan , Annema Wijtske , Groen Albert K. , Tietge Uwe J.F.
Published: February 2013

Biliary lipid secretion plays an important role in gallstone disease and reverse cholesterol transport (RCT). Using Sr-bI/Abcg5 double knockout mice (dko), the present study investigated the differential contribution of two of the most relevant transporters: adenosine triphosphate (ATP)-binding cassette subfamily G member 5 and 8 (ABCG5/G8) and scavenger receptor class B type I (SR-BI) to sterol metabolism and RCT. Plasma cholesterol levels increased in the following order, mainly due to differences in high density lipoprotein (HDL): Abcg5 ko < wild type < Sr-bI/Abcg5 dko < Sr-bI ko. Liver cholesterol content was elevated in Sr-bI ko only (P < 0.05). In Sr-bI/Abcg5 dko plasma plant sterols were highest, while hepatic plant sterols were lower compared with Abcg5 ko (P < 0.05). Under baseline conditions, biliary cholesterol secretion rates decreased in the following order: wild type > Sr-bI ko (−16%) > Abcg5 ko (−75%) > Sr-bI/Abcg5 dko (−94%), all at least P < 0.05, while biliary bile acid secretion did not differ between groups. However, under supraphysiological conditions, upon infusion with increasing amounts of the bile salt tauroursodeoxycholic acid, Abcg5 became fully rate-limiting for biliary cholesterol secretion. Additional in vivo macrophage-to-feces RCT studies demonstrated an almost 50% decrease in overall RCT in Sr-bI/Abcg5 dko compared with Abcg5 ko mice (P < 0.01). Conclusion: These data demonstrate that (1) SR-BI contributes to ABCG5/G8-independent biliary cholesterol secretion under basal conditions; (2) biliary cholesterol mass secretion under maximal bile salt-stimulated conditions is fully dependent on ABCG5/G8; and (3) Sr-bI contributes to macrophage-to-feces RCT independent of Abcg5/g8. (Hepatology 2013;)
Application of microPET imaging approaches in the study of pediatric anesthetic‐induced neuronal toxicity
Authors: Zhang Xuan , Paule Merle G. , Wang Cheng , Slikker William
Published: February 2013

Advances in pediatric and obstetric surgery have resulted in an increase in the complexity, duration and number of anesthetic procedures. Currently, the general anesthetics that are used most often have either NMDA receptor blocking or GABA receptor activating properties. It has been reported that prolonged exposure of the developing brain to a clinically relevant concentration of anesthetics that have NMDA antagonist or GABA‐mimetic properties, and/or their combinations, resulted in an extensive abnormal pattern of neuroapoptosis, and subsequent cognitive deficits in animals. Molecular imaging using positron emission tomography (PET) is a leading modality for obtaining non‐ or minimally invasive in vivo measurements of multiple biological processes in various organs. The development of microPET imaging applications has provided the ability to collect sensitive and quantitative three‐dimensional molecular information from the living brains of a variety of animals. The main aim of this review was to describe molecular imaging approaches that have been used in the study of pediatric anesthetic‐induced neuronal toxicity. Published 2013. This article is a US Government work and is in the public domain in the USA.
Synthesis, Crystal Structure, Spectral and Thermodynamic Properties of One Benzoindole Pentamethine Cyanine Dye
Authors: Zhang Xiu‐Fu , Zhao Jun‐Long , Bi Wei‐Bin , Zhang Dan‐Dan , Yang Zhi‐Yuan , Wang Lan‐Ying
Published: February 2013

One benzoindole pentamethine cyanine dye was synthesized and characterized by 1H NMR, IR, MS and UV‐Vis spectra. The UV‐Vis absorption and fluorescence spectra of the dye in chloroform, dimethyl sulfoxide, acetone, ethanol and methanol were investigated, and the λmax of the dye was in the region 682.0–689.0 nm with large molar extinction coefficients (ϵ > 105 M−1cm−1) in different solvents. The structure of the dye was also characterized and analyzed by X‐ray diffraction. Crystallographic data revealed that the dye belonged to orthorhombic, with space group P212121, a = 10.059(2) Å, b = 15.098(4) Å, c = 24.989(6) Å, V = 3794.8(15) Å3, Z = 4. The C‐H···F intermolecular hydrogen bonds were displayed in the molecular system, which were effective in the molecular packing. The aggregation behavior and thermodynamic properties of the dye in aqueous methanol solution were also studied by means of UV‐Vis spectroscopy methods. The results indicated that the dye existed monomer‐dimer equilibrium in aqueous methanol solutions. The fundamental properties of the dye, such as the dimeric association constant KD, the dimeric free energy ΔGD, the dimeric entropy ΔSD, and the dimeric enthalpy ΔHD were determined. The ΔHD of the dye was –46.0 kJ mol−1.
Photoluminescence Study on Charge Transfer Behavior of Poly(3‐hexylthiophene) and PCBM Blends
Authors: Huang Ping‐Tsung , Huang Po‐Fang , Horng Yu‐Jei , Yang Chien‐Pai
Published: February 2013

Charge transfer behavior of Poly(3‐hexylthiophene) (P3HT) and [6,6]‐phenyl‐C61‐butyric acid methyl eser (PCBM) in solutions and in films were examined by photoluminescence (PL) spectroscopy. PL study in solutions indicated that separation distance between P3HT and PCBM affected charge transfer efficiency more seriously than the interface area issue between P3HT and PCBM. P3HT/PCBM film showed very effective photo‐induced charge transfer before post‐thermal annealing on the bi‐layer P3HT/PCBM film. Charge transfer efficiency was gradually diminished by the annealing‐induced phase separation between P3HT and PCBM as revealed by increasing PL emission intensity of P3HT.
CO2 Adsorption Ability and Thermal Stability of Amines Supported on Mesoporous Silica SBA‐15 and Fumed Silica
Authors: Chao Kuei‐Jung , Klinthong Worasaung , Tan Chung‐Sung
Published: February 2013

In this study, monoamine 3‐aminopropyl silane (APS) grafted on silica supports were prepared either by post‐modification of mesoporous template‐free SBA‐15 and nonporous fumed silica with 3‐aminopropyl triethoxysilane (APTES) or by direct synthesis using a reaction mixture of APTES, TEOS and organic template P123. The CO2 adsorption capacities and efficiencies of amine (defined as CO2/N ratio) on APS grafted silica adsorbents as well as the thermal stability of grafted APS were analyzed and further compared with those of multiamine, tetraethylenepentamine (TEPA), loaded on mesoporous SBA‐15 and nonporous fumed silica. The TEPA‐loaded silica adsorbents exhibited higher CO2 adsorption capacities but lower thermal stability than the APS‐grafted silica adsorbents. The low cost and commercially available nonporous fumed silica was found to be an appropriate support for amine loading. The TEPA‐loaded fumed silica possessed a CO2 adsorption capacity of 3.97 mmole CO2/(g of adsorbent) and a CO2/N mole ratio of 0.37 under a 15% CO2/N2 mixed gas flow at 75 °C and 1 atm, which were higher than those of the TEPA‐loaded SBA‐15 due to the less CO2 diffusion hindrance. Besides, a high stability of TEPA on fumed silica in cyclic adsorption‐desorption of CO2 over the TEPA loaded on SBA‐15 was observed as well.
(Δ)[Fe(II)(phen)3]2+ Filled in the Chiral Cavitiy Constituted by {(Δ)[Fe(III)(C2O4)3](NH42+)(DMF)(H2O)32−}n
Authors: Sun Xiao‐Jing , Cheng Yi‐Feng , Feng Jun , Lu Xiao‐Ming
Published: February 2013

A chiral coordination compound {(Δ)[Fe(II)(phen)3][(Δ)Fe(III)(C2O4)3](NH4)(H2O)3(DMF)}n (phen = 1,10‐phenanthroline), (DMF = N,N'‐Dimethylformamide), has been synthesized, and the structure has been revealed by infrared spectroscopy and X‐ray single‐crystal diffraction. The framework consists of two chiral subunits. One subunit (Δ)[(Fe(III)(C2O4)3]3− which as host anion forms a chiral porous three‐dimensional supermolecular network with lattice water, lattice DMF and lattice ammonium cation through hydrogen bonds. And then the other is Δ[Fe(II)(phen)3]2+ which as guest cation fills in the chiral cavity located in the previously mentioned host porous network.
Mutational Analysis of Methyl‐CpG Binding Protein 2 (MECP2) Gene in Indian Cases of Rett Syndrome
Authors: Das Dhanjit Kumar , Udani Vrajesh , Sanghavi Daksha , Adhia Rashmi , Maitra Anurupa
Published: February 2013

Rett syndrome (RTT) is an X‐linked postnatal neurological disorder, primarily affecting females and characterized by regression, epilepsy, stereotypical hand movements, and motor abnormalities. Its prevalence is about 1 in 10,000 female births. RTT is caused by mutations within methyl CpG‐binding protein 2 (MECP2) gene. Over 200 individual nucleotide changes in the gene, which cause pathogenic mutations, have been reported; however, eight most commonly occurring missense and nonsense mutations account for almost 70% of all mutations. RTT cases have also been reported from India. The phenotype (classical and atypical inclusive) has many differentials. However, a genetically based confirmed diagnosis would help in management and counseling. In this pilot study we have analyzed MECP2 mutations in ten Indian sporadic patients diagnosed clinically as having RTT. Two mutations and one novel variant in MECP2 have been detected. Missense mutations p.R133C and c.806delG have been detected. The missence mutation p.R133C was the part of eight hotspots reported in Rett patients. This patient met all the essential criteria except delayed onset of regression. The other c.806delG mutation positive patient also fulfilled all the obligatory criteria of classical RTT. Another clinically atypical Rett patient showed a novel mutation p.C339S in MECP2 gene. The preliminary result necessitates a large‐scale study of RTT patients to determine more precisely the influence of MECP2 mutations in Indian patients and their correlation with clinical phenotypes. J. Clin. Lab. Anal. 27:137–142, 2013. © 2013 Wiley Periodicals, Inc.
Establishment of beet molasses as the fermentation substrate for industrial vitamin B12 production by Pseudomonas denitrificans
Authors: Li Kun‐tai , Peng Wei‐fu , Zhou Jia , wei Sai‐jin , Cheng Xin
Published: February 2013

BACKGROUND

Fermentation of the industrial vitamin B12 by Pseudomonas denitrificans usually utilizes sucrose or maltose as the sole carbon source, which results in increased medium costs. In order to decrease the fermentation cost, it is crucial and essential to employ a low‐cost and convenient raw material as an alternative medium substrate for industrial vitamin B12 production.

RESULTS

The results obtained in chemically defined medium showed that glutamate and sucrose were favorable for cell growth and vitamin B12 biosynthesis of P. denitrificans. Due to containing a mass of ingredients such as sucrose, glutamate and betaine, beet molasses was consequently chosen as the main medium substrate for industrial P. denitrificans fermentation in a 120 000 L fermenter. Vitamin B12 production reached 181.75 mg L–1.

CONCLUSIONS

Beet molasses is a by‐product of the sugar industry and is thus very inexpensive, and it was proved that beet molasses was an efficient and economical medium substrate for industiral vitamin B12 fermentation by P. denitrificans. © 2013 Society of Chemical Industry