bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical Preparation of Luminescent Graphene Quantum Dots from Multiwalled Carbon Nanotubes
Authors: Shinde Dhanraj B. , Pillai Vijayamohanan K.
Published: August 2012

Green luminescent, graphene quantum dots (GQDs) with a uniform size of 3, 5, and 8.2(±0.3) nm in diameter were prepared electrochemically from MWCNTs in propylene carbonate by using LiClO4 at 90 °C, whereas similar particles of 23(±2) nm were obtained at 30 °C under identical conditions. Both these sets of GQDs displayed a remarkable quantum efficiency of 6.3 and 5.1 %, respectively. This method offers a novel strategy to synthesise size‐tunable GQDs as evidenced by multiple characterisation techniques like transmission and scanning electron microscopy, atomic force microscopy, Raman spectroscopy and X‐ray diffraction (XRD). Photoluminescence of these GQDs can be tailored by size variation through a systematic change in key process parameters, like diameter of carbon nanotube, electric field, concentration of supporting electrolyte and temperature. GQDs are promising candidates for a variety of applications, such as biomarkers, nanoelectronic devices and chemosensors due to their unique features, like high photostability, biocompatibility, nontoxicity and tunable solubility in water.
Selective Functionalization of Fullerenes with N,N‐Dihalosulfonamides as an N1 Unit: Versatile Syntheses of Aza[60]fulleroids and Aziridino[60]fullerenes and their Application to Photovoltaic Cells
Authors: Nagamachi Toshiki , Takeda Youhei , Nakayama Kazuhisa , Minakata Satoshi
Published: August 2012

Highly selective and versatile methods for the synthesis of aza[60]fulleroids and aziridino[60]fullerenes from C60 have been developed. The reactions utilized N,N‐dihalosulfonamides as an N1 source. The photophysical, electrochemical, and thermal properties of the iminofullerenes were investigated by means of UV/Vis spectroscopy, cyclic voltammetry, and thermogravimetry, respectively. Furthermore, photovoltaic cells based on the synthesized iminofullerenes were fabricated. The power conversion efficiencies (PCEs) of the devices showed moderate values ranging from 1.33 to 2.35 %.
Continuous Fermentation with Animal Cells. Part 1. Aspects of the Continuous Process
Authors: Henzler Hans‐Jürgen
Published: August 2012

Die kontinuierliche Fermentation verspricht im Vergleich zur diskontinuierlichen Prozessführung eine Reihe von Vorteilen. Dazu zählen der Langzeitbetrieb bei weitgehend konstanter Substrat‐, Zellmasse und Produktkonzentration sowie eine hohe Anlagen‐Produktivität. Demgegenüber stehen eine komplexere Fermentationstechnik und die Notwendigkeit, die Langzeitsterilität bei sterilen Prozessen zu sichern. Einführend werden die Grundlagen der kontinuierlichen Fermentation zum Anfahrvorgang und stationären Betrieb behandelt. Eine konsequent angewendete dimensionslose Formulierung der maßgebenden Zusammenhänge ermöglicht eine kompakte und besonders übersichtliche Darstellung der grundlegenden Gesetzmäßigkeiten zur Zellmasse‐ und Produktbildung. Es werden die Besonderheiten der kontinuierlichen Fermentation mit und ohne Zellrückhaltung gegenübergestellt und grundlegende Aspekte der kontinuierlichen Fermentation mit Zellrückhaltung besprochen.
Preparation of Multi‐Metal Oxide Hollow Sphere Using Layered Double Hydroxide Precursors
Authors: Yang Miaosen , Zhang Guoxin , Wu Caiying , Chang Zheng , Sun Xiaoming , Duan Xue
Published: August 2012

A simple and versatile synthesis method was developed to prepare inorganic multi‐metal oxide hollow spheres with tunable compositions. The colloidal nanosheets of layered double hydroxides (LDH) with pre‐determined compositions were used as precursors for multi‐metal oxides and carbon spheres (CSs) prepared by hydrothermal carbonization of glucose were used as hard templates. Electrostatic force drove the positively charged LDH nanosheets to be anchored by the negatively charged CSs once they were mixed, leading to the formation of core‐shell structures. Finally, multi‐metal oxides with hollow spherical structures were obtained by calcination. These hollow spheres were characterized by X‐ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and inductively coupled plasma (ICP). Results revealed that the as‐prepared oxide hollow spheres could exactly inherit the metal‐to‐metal ratios of initial LDH precursors, which provided an effective way to control the compositions of oxide shells. This strategy was suitable for preparation of a series of oxide hollow spheres from binary to multi‐component ones, including MgO/Al2O3, MgO/Fe3O4, NiO/Al2O3, and ZnO/NiO/Al2O3.
Stereoselective Synthesis of Optically Active Hydrobenzoins via Asymmetric Hydrogenation of Benzils with Ru(OTf)(TsDPEN)(η6‐cymene) as the Pre‐catalyst
Authors: Huang Xiaofei , Li Naikai , Geng Zhicong , Pan Fengfeng , Wang Xingwang
Published: August 2012

Optically active hydrobenzoins are very important building blocks for further derivation of biologically active complexes, natural products, and pharmaceutical compounds. In this paper, A practical approach has been developed for asymmetric hydrogenation of benzils with Ru(OTf)(TsDPEN)(η6‐cymene) as a pre‐catalyst in methanol. Therefore, a series of chiral hydrobenzoins was synthesized in good yields with good to moderate diastereoselectivities and good to excellent enantioselectivities.
Palladium‐Catalyzed N‐Alkylation of Amides and Amines with Alcohols Employing the Aerobic Relay Race Methodology
Authors: Yu Xiaochun , Jiang Lan , Li Qiang , Xie Yuanyuan , Xu Qing
Published: August 2012

Possibly because homogeneous palladium catalysts are not typical borrowing hydrogen catalysts and ligands are thus ineffective in catalyst activation under conventional anaerobic conditions, they had not been used in the N‐alkylation reactions of amines/amides with alcohols in the past. By employing the aerobic relay race methodology with Pd‐catalyzed aerobic alcohol oxidation being a more effective protocol for alcohol activation, ligand‐free homogeneous palladiums are successfully used as active catalysts in the dehydrative N‐alkylation reactions, giving high yields and selectivities of the alkylated amides and amines. Mechanistic studies implied that the reaction most probably proceeds via the novel relay race mechanism we recently discovered and proposed.
Highly Efficient Synthesis of Unsymmetrical 3,3′‐Bis(1H‐indol‐3‐yl)methanes in Water
Authors: Lin Hua , Zang Yang , Sun Xingwen , Lin Guoqiang
Published: August 2012

A simple and practical approach for the preparation of unsymmetric bis(indolyl)methanes (BIMs) was realized by Lewis acid InBr3‐catalyzed Friedel‐Crafts reaction of indoles with 3‐indolyl‐substituted phthalides in water.
Catalytic, Conjugate Reduction‐Aldol Addition Reaction of β′‐Oxoalkyl α,β‐Unsaturated Carboxylates
Authors: Zheng Aijun , Jiang Lan , Li Zhengning
Published: August 2012

Intramolecular conjugate reduction‐aldol addition reactions of β′‐oxoalkyl α,β‐unsaturated carboxylates were performed in the presence of copper catalysts generated in situ from copper salts, phosphine ligands and silanes. Moderate to good yields and high diastereoselectivities were obtained in 15 min to 3 h using bis[(2‐diphenylphosphino)phenyl] ether as the ligand.
Incidence and predictors of venous thromboembolism (VTE) among ambulatory high‐risk cancer patients undergoing chemotherapy in the United States
Authors: Khorana Alok A. , Dalal Mehul , Lin Jay , Connolly Gregory C.
Published: August 2012

BACKGROUND:

Recent studies suggest that thromboprophylaxis is beneficial in preventing venous thromboembolism (VTE) in cancer outpatients, but this is not widely adopted because of incomplete understanding of the contemporary incidence of VTE and concerns about bleeding. Therefore, the authors examined the incidence and predictors of VTE in ambulatory patients with bladder, colorectal, lung, ovary, pancreas, or gastric cancers.

METHODS:

Data were extracted from a large health care claims database of commercially insured patients in the United States between 2004 and 2009. Demographic and clinical characteristics of the cancer cohort (N = 17,284) and an age/sex‐matched, noncancer control cohort were evaluated. VTE incidence was recorded during a 3‐month to 12‐month follow‐up period after the initiation of chemotherapy. Multivariate analyses were conducted to identify independent predictors of VTE and bleeding.

RESULTS:

The mean age of the study population was 64 years, and 51% of patients were women. VTE occurred in 12.6% of the cancer cohort (n = 2170) over 12 months after the initiation of chemotherapy versus 1.4% of controls (n = 237; P < .0001); incidence ranged by cancer type from 19.2% (pancreatic cancer) to 8.2% (bladder cancer). Predictors of VTE included type of cancer, comorbidities (Charlson Comorbidity Index score or obesity), and commonly used specific antineoplastic or supportive care agents (cisplatin, bevacizumab, and erythropoietin).

CONCLUSIONS:

This large, contemporary, real‐world analysis confirmed high rates of VTE in select patients with solid tumors and suggested that the incidence of VTE is high in the real‐world setting. Awareness of the benefits of targeted thromboprophylaxis may result in a clinically significant reduction in the burden of VTE in this population. Cancer 2013. © 2012 American Cancer Society.
The addition of low‐dose‐rate brachytherapy and androgen‐deprivation therapy decreases biochemical failure and prostate cancer death compared with dose‐escalated external‐beam radiation therapy for high‐risk prostate cancer
Authors: Shilkrut Mark , Merrick Gregory S. , McLaughlin P. William , Stenmark Matthew H. , Abu‐Isa Eyad , Vance Sean M. , Sandler Howard M. , Feng Felix Y. , Hamstra Daniel A.
Published: August 2012

BACKGROUND:

The objective of this study was to determine whether the addition of low‐dose‐rate brachytherapy or androgen‐deprivation therapy (ADT) improves clinical outcome in patients with high‐risk prostate cancer (HiRPCa) who received dose‐escalated radiotherapy (RT).

METHODS:

Between 1995 and 2010, 958 patients with HiRPCa were treated at Schiffler Cancer Center (n = 484) or at the University of Michigan (n = 474) by receiving either dose‐escalated external‐beam RT (EBRT) (n = 510; minimum prescription dose, 75 grays [Gy]; median dose, 78 Gy) or combined‐modality RT (CMRT) consisting of 103Pd implants (n = 369) or 125I implants (n = 79) both with pelvic irradiation (median prescription dose, 45 Gy). The cumulative incidences of biochemical failure (BF) and prostate cancer‐specific mortality (PCSM) were estimated by using the Kaplan‐Meier method and Fine and Gray regression analysis.

RESULTS:

The median follow‐up was 63.2 months (interquartile range, 35.4‐99.0 months), and 250 patients were followed for >8 years. Compared with CMRT, patients who received EBRT had higher prostate‐specific antigen levels, higher tumor classification, lower Gleason sum, and more frequent receipt of ADT for a longer duration. The 8‐year incidence BF and PCSM among patients who received EBRT was 40% (standard error, 38%‐44%) and 13% (standard error, 11%‐15%) compared with 14% (standard error, 12%‐16%; P < .0001) and 7% (standard error 6%‐9%; P = .003) among patients who received CMRT. On multivariate analysis, the hazard ratios (HRs) for BF and PCSM were 0.35 (95% confidence interval [CI], 0.23‐0.52; P < .0001) and 0.41 (95% CI, 0.23‐0.75; P < .003), favoring CMRT. Increasing duration of ADT predicted decreased BF (P = .04) and PCSM (P = .001), which was greatest with long‐term ADT (BF: HR, 0.33; P < .0001; 95% CI, 0.21‐0.52; PCSM: HR, 0.30; P = .001; 95% CI, 0.15‐0.6) even in the subgroup that received CMRT.

CONCLUSIONS:

In this retrospective comparison, both low‐dose‐rate brachytherapy boost and ADT were associated with decreased risks of BF and PCSM compared with EBRT. Cancer 2013. © 2012 American Cancer Society.
Randomized study of 2 reduced‐intensity conditioning strategies for human leukocyte antigen‐matched, related allogeneic peripheral blood stem cell transplantation
Authors: Blaise Didier , Tabrizi Reza , Boher Jean‐Marie , Le Corroller‐Soriano Anne‐Gaëlle , Bay Jacques‐Olivier , Fegueux Nathalie , Boiron Jean‐Michel , Fürst Sabine , Castagna Luca , Chabannon Christian , Boyer‐Chammard Agnes , Milpied Noël , Labussière‐Wallet Hélène , Faucher Catherine , Bardou Valerie‐Jeanne , Mohty Mohamad , Michallet Mauricette
Published: August 2012

BACKGROUND:

The optimal intensity of reduced‐intensity conditioning (RIC) before allogeneic hematopoietic stem cell transplantation (allo‐HSCT) remains uncertain.

METHODS:

In this centrally randomized phase 2 study, the authors compared 2 different strategies of RIC. In total, 139 patients (median age, 54 years; range, 21‐65 years) with hematologic malignancies underwent allo‐HSCT from a human leukocyte antigen‐identical sibling after conditioning combining fludarabine with either busulfan and rabbit antithymocyte‐globulin (BU‐rATG) (n = 69) or total body irradiation (TBI) (n = 70). Postgraft immunosuppression consisted of cyclosporin A in all patients with the addition of mycophenolate‐mophetil after TBI.

RESULTS:

The median follow‐up was 54 months (range, 26‐88 months). One‐year overall survival rate was identical in both groups. Four patients experienced graft‐failure after TBI. The incidence of grade 2 through 4 acute graft‐versus‐host‐disease was greater after BU‐rATG than after TBI (47% vs 27%; P = .01), whereas no difference was observed with chronic graft‐versus‐host‐disease. The BU‐rATG group had a higher objective response rate (65% vs 46%; P = .05) and a lower relapse rate (27% vs 54%; P < .01). However, the nonrelapse mortality rate was higher after BU‐rATG than after TBI (38% vs 22%; P = .027). At 5 years, the overall and progression‐free survival rates were 41% and 29%, respectively, and did not differ statistically between groups. A detrimental effect on some parameters of quality of life was more pronounced after BU‐rATG, but recovery was identical in both groups. The mean total cost per patient, including the cost to treat disease progression post‐transplantation, did not differ statistically between groups.

CONCLUSIONS:

Five years after transplantation, the BU‐rATG regimen was associated with greater disease control. However, because of the higher nonrelapse mortality rate, this did not translate into better overall or progression‐free survival. Cancer 2013. © 2012 American Cancer Society.
Enhanced Van der Waals calculations in genetic algorithms for protein structure prediction
Authors: Bonetti Daniel R.F. , Delbem Alexandre C.B. , Travieso Gonzalo , de Souza Paulo Sergio L.
Published: August 2012

Several ab initio computational methods for protein structure prediction have been designed using full‐atom models and force field potentials to describe interactions among atoms. Those methods involve the solution of a combinatorial problem with a huge search space. Genetic algorithms (GAs) have shown significant performance increases for such methods. However, even a small protein may require hundreds of thousands of energy function evaluations making GAs suitable only for the prediction of very small proteins. We propose an efficient technique to compute the van der Waals energy (the greatest contributor to protein stability) speeding up the whole GA. First, we developed a Cell‐List Reconstruction procedure that divides the tridimensional space into a cell grid for each new structure that the GA generates. The cells restrict the calculations of van der Waals potentials to ranges in which they are significant, reducing the complexity of such calculations from quadratic to linear. Moreover, the proposal also uses the structure of the cell grid to parallelize the computation of the van der Waals energy, achieving additional speedup. The results have shown a significant reduction in the run time required by a GA. For example, the run time for the prediction of a protein with 147,980 atoms can be reduced from 217 days to 7 h. Copyright © 2012 John Wiley & Sons, Ltd.
Solar Hydrogen Generation with Wide‐Band‐Gap Semiconductors: GaP(100) Photoelectrodes and Surface Modification
Authors: Kaiser Bernhard , Fertig Dominic , Ziegler Jürgen , Klett Joachim , Hoch Sascha , Jaegermann Wolfram
Published: August 2012

GaP, with its large band gap of 2.26 eV (indirect) and 2.78 eV (direct), is a very promising candidate for direct photoelectrochemical water splitting. Herein, p‐GaP(100) is investigated as a photocathode for hydrogen generation. The samples are characterized after each preparation step regarding how their photoelectrochemical behavior is influenced by surface composition and structure using a combination of electrochemical and surface‐science preparation and characterization techniques. The formation of an Ohmic back contact employing an annealed gold layer and the removal of the native oxides using various etchants are studied. It turns out that the latter has a pronounced effect on the surface composition and structure and therefore also on the electronic properties of the interface. The formation of a thin Ga2O3 buffer layer on the p‐GaP(100) surface does not lead to a clear improvement in the photoelectrochemical efficiency, neither do Pt nanocatalyst particles deposited on top of the buffer layer. This behavior can be understood by the electronic structure of these layers, which is not well suited for an efficient charge transfer from the absorber to the electrolyte. First experiments show that the efficiency can be considerably improved by employing a thin GaN layer as a buffer layer on top of the p‐GaP(100) surface.
1‐V continuous‐time equalizers for multi‐gigabit short‐haul optical fiber communications
Authors: Gimeno C. , Aldea C. , Aznar F. , Sánchez‐Azqueta C. , Celma S.
Published: August 2012

Two new CMOS analog continuous‐time equalizers for high‐speed short‐haul optical fiber communications are presented in this paper. The proposed structures compensate the limited bandwidth‐length product of 1‐mm step‐index polymer optical fiber channels (45 MHz, 100 m) and have been designed in a standard 0.18‐µm CMOS process. The equalizers are aimed for multi‐gigabit short‐range applications, targeting up to 2 Gb/s through a 50‐m step‐index polymer optical fiber. The prototypes operate with a single supply voltage of only 1 V and overcome the severe limitations suffered by the widely used degenerated differential pair caused by the low supply voltage. Copyright © 2012 John Wiley & Sons, Ltd.
Weak patriline effects are present in the cuticular hydrocarbon profiles of isolated Formica exsecta ants but they disappear in the colony environment
Authors: Martin Stephen , Trontti Kalevi , Shemilt Sue , Drijfhout Falko , Butlin Roger , Jackson Duncan
Published: August 2012

Chemical recognition cues are used to discriminate among species, con‐specifics, and potentially between patrilines in social insect colonies. There is an ongoing debate about the possible persistence of patriline cues despite evidence for the mixing of colony odors via a “gestalt” mechanism in social insects, because patriline recognition could lead to nepotism. We analyzed the variation in recognition cues (cuticular hydrocarbons) with different mating frequencies or queen numbers in 688
Formica exsecta ants from 76 colonies. We found no increase in the profile variance as genetic diversity increased, indicating that patriline effects were absent or possibly obscured by a gestalt mechanism. We then demonstrated that an isolated individual's profile changed considerably relative to their colony profile, before stabilizing after 5 days. We used these isolated individuals to eliminate the masking effects of the gestalt mechanism, and we detected a weak but statistically significant patriline effect in isolated adult workers and also in newly emerged callow workers. Thus, our evidence suggests that genetic variation in the cuticular hydrocarbon profile of
F. exsecta ants (n‐alkanes and alkenes) resulted in differences among patrilines, but they were obscured in the colony environment, thereby avoiding costly nepotistic behaviors.
Salen‐Type Triple‐Decker Trinuclear Dy3 Complexes Showing Slow Magnetic Relaxation Behavior
Authors: Yang Fan , Yan Pengfei , Li Quan , Chen Peng , Li Guangming
Published: August 2012

Two new Dy3 sandwich complexes, namely, [Dy3La3(CH3OH)2(NO3)3]·CH2Cl2·CH3OH·2H2O [1, H2La = N,N′‐bis(salicylidene)‐1,2‐phenylenediamine] and [Dy3Lb3(OAc)3]·3CH3OH·H2O [2, H2Lb = N,N′‐bis(3‐methoxysalicylidene)‐1,2‐phenylenediamine], have been synthesized from the reactions of a tetradentate salen‐type ligand (H2La) with Dy(NO)3·6H2O and a hexadentate salen‐type ligand (H2Lb) with Dy(OAc)3·6H2O. X‐ray crystallographic analysis reveals that both 1 and 2 have a similar new triple‐decker trinuclear sandwich structure. Magnetic studies indicate that 1 exhibits an antiferromagnetic interaction between the Dy3+ ions, whereas 2 exhibits a ferromagnetic interaction between spin carriers. Although both 1 and 2 display slow magnetic relaxation behavior, two relaxation processes were observed in 2, which expand on the recent reports of pure 4f‐type single molecule magnets (SMMs).
An Electron‐Rich {RuNO}6 Complex: trans‐[Ru(DMAP)4(NO)(OH)]2+ – Structure and Reactivity
Authors: Osa Codesido Nicolás , De Candia Ariel G. , Weyhermüller Thomas , Olabe José A. , Slep Leonardo D.
Published: August 2012

The pseudo‐octahedral nitrosyl species trans‐[Ru(DMAP)4(NO)(OH)]2+ [12+, DMAP = 4‐(dimethylamino)pyridine] was prepared by the reaction between [Ru(DMAP)5(H2O)]2+ and NaNO2 under mild conditions (room temperature, pH = 6–8), and precipitated with NaBF4 or NaPF6. Single‐crystal X‐ray diffraction data of 1(BF4)2·2H2O point to a {RuNO}6 electronic configuration of the cation, although there is a significant deviation from the expected linear arrangement of the RuNO moiety (Ru–N–O angle: 169.3°). The remarkably low wavenumber of the NO stretching band (νNO) of 1832 cm–1 in the solid state corresponds to an electron‐rich ligand environment with strong backbonding interactions between dπ metal orbitals and π*NO orbitals of the (formal) NO+ (nitrosonium) ligand. Consistently, the complex acts as a poor electrophile: it is extremely unreactive toward OH– and toward the stronger nucleophile cysteine. Cyclic voltammetry (CV) experiments show three reduction processes in acetonitrile. The first one at –0.50 V [vs. Ag/AgCl, KCl(s)] is reversible on the CV time scale. Spectroelectrochemical experiments (IR and UV/Vis) suggest that the reduced complex has a {RuNO}7 configuration. The νNO wavenumber of 1603 cm–1 agrees with a reduction mostly centered at the nitrosyl ligand. This species appears to be inert toward substitution in the coordination sphere, and the original {RuNO}6 ion can be quantitatively recovered upon oxidation. In contrast, further reduction of this species is completely irreversible, even on the CV timescale, which is probably due to the lability of the presumably formed nitroxyl (NO–) ligand.
Synthesis and Characterization of Ultrathin Tin‐Doped Zinc Oxide Nanowires
Authors: Jin Yizheng , Yi Qing , Zhou Limin , Chen Dongdong , He Haiping , Ye Zhizhen , Hong Jinhua , Jin Chuanhong
Published: August 2012

Ultrathin tin‐doped zinc oxide (Sn‐doped ZnO) nanowires with uniform diameters of 2.3 ± 0.2 nm were synthesized by means of a facile colloidal method employing an aminolysis approach. This finding suggests that the introduction of group IV dopants may serve as an effective strategy to control the shape of doped ZnO nanocrystals. This doping procedure may be extended to the synthesis of other doped oxide nanocrystals.
Effects of nanopolystyrene on the feeding behavior of the blue mussel (Mytilus edulis L.)
Authors: Wegner A. , Besseling E. , Foekema E.M. , Kamermans P. , Koelmans A.A.
Published: August 2012

As the industrial production of nanoplastic and the degradation of microplastic into smaller particles at sea increase, the potential amount of nanoplastics in the marine environment rises. It has been reported that mussels uptake 100-nm polystyrene (PS) beads; to date, however, the effects of this uptake on the organism are unknown. In the present study, the authors investigated the effects of 30-nm PS on the feeding behavior of the blue mussel (Mytilus edulis) by exposing the organism to different nano PS and different algae (Pavlova lutheri) concentrations. The state of nano PS aggregation in the exposure medium was assessed using dynamic light scattering. In all treatments that contained nano PS, M. edulis produced pseudofeces. The total weight of the feces and pseudofeces increased with increasing nano PS and increasing algae concentration. Furthermore, M. edulis reduced its filtering activity when nano PS was present but still caused a decrease in the apparent nano PS concentration in the water. The presence of nano PS around the foot of M. edulis after the bioassay confirmed that the organism removed nano PS from the water. Chronic effect studies are therefore needed to investigate the effects of nanoplastics in M. edulis and possible consequences for its predators, including humans. Environ. Toxicol. Chem. 2012; 31: 2490–2497. © 2012 SETAC
Gene expression, glutathione status, and indicators of hepatic oxidative stress in laughing gull (Larus atricilla) hatchlings exposed to methylmercury
Authors: Jenko Kathryn , Karouna-Renier Natalie K. , Hoffman David J.
Published: August 2012

Despite extensive studies of methylmercury (MeHg) toxicity in birds, molecular effects on birds are poorly characterized. To improve our understanding of toxicity pathways and identify novel indicators of avian exposure to Hg, the authors investigated genomic changes, glutathione status, and oxidative status indicators in liver from laughing gull (Larus atricilla) hatchlings that were exposed in ovo to MeHg (0.05–1.6 µg/g). Genes involved in the transsulfuration pathway, iron transport and storage, thyroid-hormone related processes, and cellular respiration were identified by suppression subtractive hybridization as differentially expressed. Quantitative polymerase chain reaction (qPCR) identified statistically significant effects of Hg on cytochrome C oxidase subunits I and II, transferrin, and methionine adenosyltransferase RNA expression. Glutathione-S-transferase activity and protein-bound sulfhydryl levels decreased, whereas glucose-6-phosphate dehydrogenase activity increased dose-dependently. Total sulfhydryl concentrations were significantly lower at 0.4 µg/g Hg than in controls. Together, these endpoints provided some evidence of compensatory effects, but little indication of oxidative damage at the tested doses, and suggest that sequestration of Hg through various pathways may be important for minimizing toxicity in laughing gulls. This is the first study to describe the genomic response of an avian species to Hg. Laughing gulls are among the less sensitive avian species with regard to Hg toxicity, and their ability to prevent hepatic oxidative stress may be important for surviving levels of MeHg exposures at which other species succumb. Environ. Toxicol. Chem. 2012; 31: 2588–2596. © 2012 SETAC
Distinct mechanisms of endocrine disruption of DDT-related pesticides toward estrogen receptor α and estrogen-related receptor γ
Authors: Zhuang Shulin , Zhang Jing , Wen Yuezhong , Zhang Chunlong , Liu Weiping
Published: August 2012

Dichlorodiphenyltrichloroethane (DDT) is ubiquitous in the environment, and the exposure to DDT and its related pesticides has long been linked to endocrine disruption. The mechanism of endocrine disruption toward targeted receptors, however, remains unclear. Probing the molecular recognition of DDT analogs by targeted receptors at the atomic level is critical for deciphering this mechanism. Molecular dynamics (MD) simulations were applied to probe the molecular recognition process of DDT and its five analogs, including dichlordiphenyldichloroethylene (DDE), dichlorodiphenyldichloroethane (DDD), methoxychlor (MXC), p,p′-hydroxy-DDT (HPTE), and dicofol by human estrogen receptor (ER) α and human ER-related receptor (ERR) γ. Van der Waals interactions mainly drive the interactions of DDT analogs with ERα ligand-binding domain (LBD) and ERRγ LBD. Minor structural changes of DDT analogs in the number and position of chlorine and phenolic hydroxyl moiety cause differences in binding modes through aromatic stacking and hydrogen bonding and thus affect differently conformational changes of ERα LBD and ERRγ LBD. The binding of DDT analogs affects the helix 12 orientation of ERα LBD but causes no rearrangement of helix 12 of ERRγ LBD. These results extend our understanding of how DDT analogs exert their estrogen-disrupting effects toward different receptors via multiple mechanisms. Environ. Toxicol. Chem. 2012; 31: 2597–2605. © 2012 SETAC
Reanalysis of uranium toxicity data for selected freshwater organisms and the influence of dissolved organic carbon
Authors: van Dam R.A. , Trenfield M.A. , Markich S.J. , Harford A.J. , Humphrey C.L. , Hogan A.C. , Stauber J.L.
Published: August 2012

The present study reanalyzed 46 existing uranium (U) chronic toxicity datasets for four freshwater species to generate consistent toxicity measures and explore relationships between U toxicity and key physicochemical variables. Dissolved organic carbon (DOC) was consistently the best predictor of U toxicity based on 10% inhibitory concentration (IC10) and median inhibitory concentration (IC50) values, with water hardness also being a significant co-predictor of IC50 concentrations for one species. The influence of DOC on acute and chronic U toxicity was further characterized using existing data for five species, and was found to vary depending on species, DOC source, and exposure duration (acute vs chronic). The slopes of the relationships between DOC and (normalized) acute and chronic U toxicity were modeled using cumulative probability distributions. From these, slopes were selected for which to correct acute or chronic U toxicity values or hazard estimates based on the aquatic DOC concentration. The fifth percentiles of these cumulative probability distributions for acute and chronic exposure data were 0.064 and 0.090, respectively, corresponding to a 6.4 and 9.0% reduction in U toxicity relative to the toxicity at the base DOC concentration for each 1 mg/L increase in DOC concentration (over the DOC range 0–30 mg/L). Algorithms were developed to enable the adjustment of U toxicity values and U hazard estimates, depending on DOC concentrations. These algorithms will significantly enhance the environmental relevance of water quality/risk assessments for U in fresh surface waters. Environ. Toxicol. Chem. 2012; 31: 2606–2614. © 2012 SETAC
Adaptive variational multiscale method for the Stokes equations
Authors: Song Lina , Hou Yanren , Zheng Haibiao
Published: August 2012

An adaptive variational multiscale method for the Stokes equations is presented in this paper. We solve the coarse scale problem on the coarse mesh and approximate the fine scale solution by solving a series of local residual equations defined on some local fine grids, which can be implemented in parallel. In addition, we also propose a reliable local a posteriori error estimator and construct an adaptive algorithm based on the corresponding a posterior error estimate. Finally, numerical examples are presented to verify the algorithm.Copyright © 2012 John Wiley & Sons, Ltd.
Graptolites and trilobites from the Eusebio Ayala Formation (Hirnantian?–early Llandovery), Paraná Basin, eastern Paraguay
Authors: Alfaro M. B. , Uriz N. J. , Cingolani C. A. , Tortello M. F. , Bidone A. R. , Galeano Inchausti J. C.
Published: August 2012

A low‐diversity graptolite fauna from the upper part of the Eusebio Ayala Formation exposed in the intracratonic Paraná Basin of eastern Paraguay is reported herein. The sections studied are composed dominantly of red micaceous mudstones with intercalations of purple sandstones from a series of clay quarries (Santa Elena; Galeano; Western Itauguá) around Itauguá city. The graptolites Metaclimacograptus sp., Normalograptus cf. ajjeri (Legrand), and Normalograptus cf. medius (Törnquist) indicate an early Llandovery age for the upper Eusebio Ayala unit. Compared to coeval, postglacial successions in southwestern Gondwana, the graptolites studied have their closest affinities with those from the Rhuddanian lower Lipeón (Subandean Ranges, northwestern Argentina) and La Chilca (Precordillera) formations. In addition, a trilobite assemblage dominated by the genus Mucronaspis was collected from the Eusebio Ayala Formation type locality near Eusebio Ayala city. The latter represents an isolated small outcrop which seems to be latest Ordovician (Hirnantian) in age. Copyright © 2012 John Wiley & Sons, Ltd.
A demonstration of the necessity and feasibility of using a clumsy decision analytic approach on wicked environmental problems
Authors: Stahl Cynthia , Cimorelli Alan
Published: August 2012

Because controversy, conflict, and lawsuits frequently characterize US Environmental Protection Agency (USEPA) decisions, it is important that USEPA decision makers understand how to evaluate and then make decisions that have simultaneously science-based, social, and political implications. Air quality management is one category of multidimensional decision making at USEPA. The Philadelphia, Pennsylvania metropolitan area experiences unhealthy levels of ozone, fine particulate matter, and air toxics. Many ozone precursors are precursors for particulate matter and certain air toxics. Additionally, some precursors for particulate matter are air toxics. However, air quality management practices have typically evaluated these problems separately. This approach has led to the development of independent (and potentially counterproductive) implementation strategies. This is a methods article about the necessity and feasibility of using a clumsy approach on wicked problems, using an example case study. Air quality management in Philadelphia is a wicked problem. Wicked problems are those where stakeholders define or view the problem differently, there are many different ways to describe the problem (i.e., different dimensions or levels of abstraction), no efficient or optimal solutions exist, and they are often complicated by moral, political, or professional dimensions. The USEPA has developed the multicriteria integrated resource assessment (MIRA) decision analytic approach that engages stakeholder participation through transparency, transdisciplinary learning, and the explicit use of value sets; in other words, a clumsy approach. MIRA's approach to handling technical indicators, expert judgment, and stakeholder values makes it a potentially effective method for tackling wicked environmental problems. Integr Environ Assess Manag 2013; 9: 17–30. © 2012 SETAC
Risk factors for gallbladder cancer: A case–control study
Authors: Jain Kajal , Sreenivas V. , Velpandian T. , Kapil Umesh , Garg Pramod Kumar
Published: August 2012

Risk factors for gallbladder cancer (GBC) except gallstones are not well known. The objective was to study the risk factors for GBC. In a case–control study, 200 patients with GBC, 200 healthy controls and 200 gallstones patients as diseased controls were included prospectively. The risk factors studied were related to socioeconomic profile, life style, reproduction, diet and bile acids. On comparing GBC patients (mean age 51.7 years; 130 females) with healthy controls, risk factors were chemical exposure [odd ratios (OR): 7.0 (2.7–18.2); p < 0.001)], family history of gallstones [OR: 5.3 (1.5–18.9); p < 0.01)], tobacco [OR: 4.1 (1.8–9.7); p < 0.001)], fried foods [OR: 3.1 (1.7–5.6); p < 0.001], joint family [OR: 3.2 (1.7–6.2); p < 0.001], long interval between meals [OR: 1.4 (1.2–1.6); p < 0.001] and residence in Gangetic belt [OR: 3.3 (1.8–6.2); p < 0.001]. On comparing GBC cases with gallstone controls, risk factors were female gender [OR: 2.4 (1.3–4.3); p = 0.004], residence in Gangetic belt [OR: 2.3 (1.2–4.4); p = 0.012], fried foods [OR: 2.5 (1.4–4.4); p < 0.001], diabetes [OR: 2.7 (1.2–6.4); p = 0.02)], tobacco [OR 3.8 (1.7–8.1); p < 0.001)] and joint family [OR: 2.1 (1.2–3.4); p = 0.004]. The ratio of secondary to primary bile acids was significantly higher in GBC cases than gallstone controls (20.8 vs. 0.44). Fried foods, tobacco, chemical exposure, family history of gallstones, residence in Gangetic belt and secondary bile acids were significant risk factors for GBC.
Diagnostic value of fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography for the detection of metastases in non–small‐cell lung cancer patients
Authors: Wu Yihua , Li Peiwei , Zhang Honghe , Shi Yu , Wu Han , Zhang Jinjie , Qian Yufeng , Li Chao , Yang Jun
Published: August 2012

In the recent years, fluorine 18 fluorodeoxyglucose (18F‐FDG) positron emission tomography (PET)/computed tomography (CT) has emerged as a new modality for staging non–small‐cell lung cancer (NSCLC) patients. The aim of this meta‐analysis was to assess the diagnostic value of 18F‐FDG PET/CT in detecting metastatic lesions in NSCLC patients. Meta‐analysis methods were used to pool sensitivity, specificity, positive and negative likehood ratios, diagnostic odd ratios and to construct a summary receiver‐operating characteristic curve. Data from included studies were pooled to compare the diagnostic accuracy between PET/CT and PET or CT alone in nodal staging. Totally, 56 studies involving 8,699 patients met the inclusion criteria. The pooled sensitivities and specificities of 18F‐FDG PET/CT were 0.72 [95% confidence interval (CI): 0.65–0.78] and 0.91 (95% CI: 0.86–0.94) in determining mediastinal nodal staging; 0.71 (95% CI: 0.60–0.80) and 0.83 (95% CI: 0.77–0.88) in intrathoracic staging; 0.78 (95% CI: 0.64–0.87) and 0.90 (95% CI: 0.84–0.94) in intrathoracic staging on a per‐node basis. For detecting extrathoracic metastases, the pooled sensitivities and specificities of 18F‐FDG PET/CT were 0.77 (95% CI: 0.47–0.93) and 0.95 (95% CI: 0.92–0.97) for all extrathoracic metastases; 0.91 (95% CI: 0.80–0.97) and 0.98 (95% CI: 0.94–0.99) for bone metastases. 18F‐FDG PET/CT is beneficial in detecting lymph node metastases and extrathoracic metastases although PET/CT showed low sensitivity in detecting brain metastases. 18F‐FDG PET/CT confers significantly higher sensitivity and specificity than contrast‐enhanced CT (both p < 0.01) and higher sensitivity than 18F‐FDG PET in staging NSCLC (p < 0.05).
Dynamic variations of c‐Fos expression in the spinal cord exposed to intramuscular hypertonic saline‐induced muscle nociception
Authors: Chen Y.‐K. , Lei J. , Jin L. , Tan Y.‐X. , You H.‐J.
Published: August 2012

Background

Numerous studies focus on intramuscular (i.m.) injection of hypertonic saline‐induced muscle pain and nociception. The spatio‐temporal characteristics and dynamic variation of spinal neuronal activities elicited by i.m. hypertonic saline remain unknown.

Methods

The spatio‐temporal variations of c‐Fos expression in the lumbar spinal cord exposed to i.m. injection of 5.8% saline were investigated in male rats.

Results

After a unilateral i.m. 5.8% saline injection, c‐Fos expression in dorsal horn of spinal L4‐6 segments was significantly enhanced bilaterally (p < 0.05 and p < 0.001). These 5.8% saline‐induced bilateral spinal Fos expression occurred rapidly 0.5 h following the i.m. injection, and reached the peak levels within 1 h, which declined gradually and returned to the control levels within 8 h. Compared with intact rats without i.m. insults, no significant influence of the spinalization on spinal c‐Fos expression was found. However, the 5.8% saline‐induced increases in Fos expression in intact and spinalized rats differed significantly. During muscle nociception, the c‐Fos expression within the superficial layer (laminae I–II) and the deep layer (laminae V–VI) in spinalized rats were significantly lower and higher than that of in intact rats (p < 0.05 and p < 0.001). Fentanyl (20 μg/kg, intraperitoneal) completely attenuated the 5.8% saline intramuscularly induced increases in c‐Fos expression in laminae III–VI (p < 0.001), but not laminae I–II.

Conclusions

It is suggested that spinal nociceptive neuronal activities in superficial and deep layers may differently be modulated by endogenous descending facilitation and inhibition, respectively.
Subchronic urinary bladder toxicity evaluation of N‐Nitrosodiphenylamine in Fischer 344 rats
Authors: Dodd Darol E. , Pluta Linda J. , Sochaski Mark A. , Funk Kathleen A. , Thomas Russell S.
Published: August 2012

Female Fischer 344 (F344) rats were exposed to N‐nitrosodiphenylamine (NDPA) by dietary feed at concentrations of 0, 250, 1000, 2000, 3000 or 4000 ppm for 5 days, 2, 4 and 13 weeks duration. Endpoints evaluated included clinical observations, body weights, urinary bladder weights, blood NDPA, gross pathology and urinary bladder histopathology. There were no NDPA exposure‐related clinical signs of toxicity. The mean body weight decreased 3% to 5% compared with the control in the 4000 ppm group during study weeks 2 through to 13. Statistically significant increases in urinary bladder weight were observed as early as after 5 days exposure and were concentration dependent at ≥ 3000 ppm. NDPA‐related urinary bladder microscopic alterations consisted of mixed cell infiltrates, increased mitosis, increased necrosis of epithelial cells, diffuse and/or nodular transitional epithelial hyperplasia and squamous metaplasia of transitional epithelium. These changes affected only rats exposed to NDPA concentrations ≥ 2000 ppm. Blood NDPA concentrations were negligible in animals exposed to ≤ 1000 ppm and ranged from 0.12 to 0.19 µg ml–1 in rats of the ≥ 2000 ppm groups at the 5 days and 2 weeks time points. A no observable adverse effect level (NOAEL) of 1000 ppm NDPA (60 mg kg–1 day–1) was selected based on the absence of urinary bladder histopathology. Copyright © 2012 John Wiley & Sons, Ltd.
Negative regulation of osteoclast precursor differentiation by CD11b and β2 integrin-B-cell lymphoma 6 signaling
Authors: Park-Min Kyung-Hyun , Lee Eun Young , Moskowitz Neal K , Lim Elisha , Lee Sun-Kyeong , Lorenzo Joseph A , Huang Chuanxin , Melnick Ari M , Purdue P Edward , Goldring Steven R , Ivashkiv Lionel B
Published: August 2012

Negative regulation of osteoclastogenesis is important for bone homeostasis and prevention of excessive bone resorption in inflammatory and other diseases. Mechanisms that directly suppress osteoclastogenesis are not well understood. In this study we investigated regulation of osteoclast differentiation by the β2 integrin CD11b/CD18 that is expressed on myeloid lineage osteoclast precursors. CD11b-deficient mice exhibited decreased bone mass that was associated with increased osteoclast numbers and decreased bone formation. Accordingly, CD11b and β2 integrin signaling suppressed osteoclast differentiation by preventing receptor activator of NF-κB ligand (RANKL)-induced induction of the master regulator of osteoclastogenesis nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) and of downstream osteoclast-related NFATc1 target genes. CD11b suppressed induction of NFATc1 by the complementary mechanisms of downregulation of RANK expression and induction of recruitment of the transcriptional repressor B-cell lymphoma 6 (BCL6) to the NFATC1 gene. These findings identify CD11b as a negative regulator of the earliest stages of osteoclast differentiation, and provide an inducible mechanism by which environmental cues suppress osteoclastogenesis by activating a transcriptional repressor that makes genes refractory to osteoclastogenic signaling. © 2013 American Society for Bone and Mineral Research
Effects of in vivo applications of peripheral blood‐derived mesenchymal stromal cells (PB‐MSCs) and platlet‐rich plasma (PRP) on experimentally injured deep digital flexor tendons of sheep
Authors: Martinello Tiziana , Bronzini Ilaria , Perazzi Anna , Testoni Stefania , De Benedictis Gulia Maria , Negro Alessandro , Caporale Giovanni , Mascarello Francesco , Iacopetti Ilaria , Patruno Marco
Published: August 2012

Tendon injuries, degenerative tendinopathies, and overuse tendinitis are common in races horses. Novel therapies aim to restore tendon functionality by means of cell‐based therapy, growth factor delivery, and tissue engineering approaches. This study examined the use of autologous mesenchymal stromal cells derived from peripheral blood (PB‐MSCs), platelet‐rich plasma (PRP) and a combination of both for ameliorating experimental lesions on deep digital flexor tendons (DDFT) of Bergamasca sheep. In particular, testing the combination of blood‐derived MSCs and PRP in an experimental animal model represents one of the few studies exploring a putative synergistic action of these treatments. Effectiveness of treatments was evaluated at 30 and 120 days comparing clinical, ultrasonographic, and histological features together with immunohistochemical expression of collagen types 1 and 3, and cartilage oligomeric matrix protein (COMP). Significant differences were found between treated groups and their corresponding controls (placebo) regarding tendon morphology and extracellular matrix (ECM) composition. However, our results indicate that the combined use of PRP and MSCs did not produce an additive or synergistic regenerative response and highlighted the predominant effect of MSCs on tendon healing, enhanced tissue remodeling and improved structural organization. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 306–314, 2013
Evidence‐Based Management and Academic Research Relevance
Authors: Booker Lorne D. , Bontis Nick , Serenko Alexander
Published: August 2012

This study seeks to understand how academic business valuation research influences business practice. It uses knowledge market theory to assess the efficacy of the evidence‐based solution to academic research relevance. Fifteen semi‐structured interviews were conducted with chartered business valuators in Canada. Interview transcripts were subjected to thematic analysis using QSR's NVivo software (QSR International, Cambridge, USA). The research findings revealed that academic research on business valuation is relevant to business valuation practitioners. The professional nature of the business valuation profession promotes evidence‐based management practices and encourages the use of academic literature in managerial decision making. Business valuation academics should not change the manner in which they publish scholarly articles. Instead, a solution to the academic relevanceproblem resides in having efficient market intermediaries in the form of knowledge translation mechanisms. Copyright © 2012 John Wiley & Sons, Ltd.