bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting chemical impacts on vertebrate endocrine systems
Authors: Nichols John W , Breen Miyuki , Denver Robert J , DiStefano Joseph J , Edwards Jeremy S , Hoke Robert A , Volz David C , Zhang Xiaowei
Published: October 2010

Animals have evolved diverse protective mechanisms for responding to toxic chemicals of both natural and anthropogenic origin. From a governmental regulatory perspective, these protective responses complicate efforts to establish acceptable levels of chemical exposure. To explore this issue, we considered vertebrate endocrine systems as potential targets for environmental contaminants. Using the hypothalamic-pituitary-thyroid (HPT), hypothalamic-pituitary-gonad (HPG), and hypothalamic-pituitary-adrenal (HPA) axes as case examples, we identified features of these systems that allow them to accommodate and recover from chemical insults. In doing so, a distinction was made between effects on adults and those on developing organisms. This distinction was required because endocrine system disruption in early life stages may alter development of organs and organ systems, resulting in permanent changes in phenotypic expression later in life. Risk assessments of chemicals that impact highly regulated systems must consider the dynamics of these systems in relation to complex environmental exposures. A largely unanswered question is whether successful accommodation to a toxic insult exerts a fitness cost on individual animals, resulting in adverse consequences for populations. Mechanistically based mathematical models of endocrine systems provide a means for better understanding accommodation and recovery. In the short term, these models can be used to design experiments and interpret study findings. Over the long term, a set of validated models could be used to extrapolate limited in vitro and in vivo testing data to a broader range of untested chemicals, species, and exposure scenarios. With appropriate modification, Tier 2 assays developed in support of the U.S. Environmental Protection Agency's Endocrine Disruptor Screening Program could be used to assess the potential for accommodation and recovery and inform the development of mechanistically based models. Environ. Toxicol. Chem. 2011;30:39–51. © 2010 SETAC
In vitro screening of organotin compounds and sediment extracts for cytotoxicity to fish cells
Authors: Giltrap Michelle , Macken Ailbhe , McHugh Brendan , McGovern Evin , Foley Barry , Davoren Maria
Published: October 2010

The present study reports an in vitro screening method for contaminants in sediment samples utilizing an RTG-2 cell line. This technique integrates cytotoxicity testing with analytical chemistry with the aim of achieving a toxicity evaluation of the sediment sample. The toxic effect of individual organotin (OT) compounds and their presence in the sediment sample is the focus of the present study; however, other contaminants are also discussed. The following OT compounds: tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), triphenyltin (TPT), diphenyltin (DPT), and a sediment solvent extract are exposed to the RTG-2 fish cell line. Both the alamar blue (AB) and neutral red (NR) assays are used to assess cytotoxicity after 24-h and 96-h exposure. Methodology for preparation of a sediment solvent extract suitable for biological testing and analytical determination is also described. With the RTG-2 cells, the AB and NR assays had comparable sensitivity for each individual OT compound exposure after 24 h, with TPT being the most toxic compound tested. The individual OT compound concentrations required to induce a 50% toxic effect on the cells (369 ng ml−1 TBT, 1,905 ng ml−1 DBT) did not equate to the concentrations of these contaminants present in the sediment extract that induced a 50% effect on the cells (294 ng ml−1 TBT, 109 ng ml−1 DBT). The solvent extract therefore exhibited a greater toxicity, and this suggests that the toxic effects observed were not due to OT compounds alone. The presence of other contaminants in the solvent extract is confirmed with chemical analysis, warranting further toxicity testing of contaminant mixtures and exposure to the cell line to further elucidate a complete toxicity evaluation. Environ. Toxicol. Chem. 2011;30:154–161. © 2010 SETAC
Species extrapolation for the 21st century
Authors: Celander Malin C , Goldstone Jared V , Denslow Nancy D , Iguchi Taisen , Kille Peter , Meyerhoff Roger D , Smith Ben A , Hutchinson Thomas H , Wheeler James R
Published: October 2010

Safety factors are used in ecological risk assessments to extrapolate from the toxic responses of laboratory test species to all species representing that group in the environment. More accurate extrapolation of species responses is important. Advances in understanding the mechanistic basis for toxicological responses and identifying molecular response pathways can provide a basis for extrapolation across species and, in part, an explanation for the variability in whole organism responses to toxicants. We highlight potential short- and medium-term development goals to meet our long-term aspiration of truly predictive in silico extrapolation across wildlife species' response to toxicants. A conceptual approach for considering cross-species extrapolation is presented. Critical information is required to establish evidence-based species extrapolation, including identification of critical molecular pathways and regulatory networks that are linked to the biological mode of action and species' homologies. A case study is presented that examines steroidogenesis inhibition in fish after exposure to fadrozole or prochloraz. Similar effects for each compound among fathead minnow, medaka, and zebrafish were attributed to similar inhibitor pharmacokinetic/pharmacodynamic distributions and sequences of cytochrome P45019A1/2 (CYP19A1/2). Rapid advances in homology modeling allow the prediction of interactions of chemicals with enzymes, for example, CYP19 aromatase, which would eventually allow a prediction of potential aromatase toxicity of new compounds across a range of species. Eventually, predictive models will be developed to extrapolate across species, although substantial research is still required. Knowledge gaps requiring research include defining differences in life histories (e.g., reproductive strategies), understanding tissue-specific gene expression, and defining the role of metabolism on toxic responses and how these collectively affect the power of interspecies extrapolation methods. Environ. Toxicol. Chem. 2011;30:52–63. © 2010 SETAC
Spectral p‐multigrid discontinuous Galerkin solution of the Navier–Stokes equations
Authors: Bassi F. , Franchina N. , Ghidoni A. , Rebay S.
Published: October 2010

Discontinuous Galerkin (DG) methods are very well suited for the construction of very high‐order approximations of the Euler and Navier–Stokes equations on unstructured and possibly nonconforming grids, but are rather demanding in terms of computational resources. In order to improve the computational efficiency of this class of methods, a high‐order spectral element DG approximation of the Navier–Stokes equations coupled with a p‐multigrid solution strategy based on a semi‐implicit Runge–Kutta smoother is considered here. The effectiveness of the proposed approach in the solution of compressible shockless flow problems is demonstrated on 2D inviscid and viscous test cases by comparison with both a p‐multigrid scheme with non‐spectral elements and a spectral element DG approach with an implicit time integration scheme. Copyright © 2010 John Wiley & Sons, Ltd.
Peristaltic motion of an Oldroyd‐B fluid in a channel with compliant walls
Authors: Hayat T. , Javed Maryiam , Ali N.
Published: October 2010

This paper is an analysis of the peristaltic flow of an Oldroyd‐B fluid in a channel with compliant walls. The flow is induced by the sinusoidal waves on the channel walls. A series solution of the resulting boundary value problem is derived under small amplitude assumption. Emphasis is placed on determining the effects of various interesting flow parameters. Copyright © 2010 John Wiley & Sons, Ltd.
Finite element simulation of sound propagation concerning meteorological conditions
Authors: Nomura T. , Takagi K. , Sato S.
Published: October 2010

A finite element analysis method is investigated for the sound propagation problem in which meteorological conditions, such as wind or stratified atmospheric temperature distribution, are concerned. The basic equations are the coupled partial differential equation system in which the sound pressure and the fluid particle velocity are unknown variables. The quantities associated to the ambient atmospheric medium are assumed steady. Performance of the time integration methods are compared. The outgoing boundary condition and the impedance boundary conditions are introduced in the computational procedure. Vibrating thin flat plate as the sound source can be treated in terms of the fluid particle velocity on the plate surfaces. All these features are investigated through a number of numerical examples and the performances are satisfactory ones. Copyright © 2010 John Wiley & Sons, Ltd.
Influencing factors in image‐based fluid–structure interaction computation of cerebral aneurysms
Authors: Torii Ryo , Oshima Marie , Kobayashi Toshio , Takagi Kiyoshi , Tezduyar Tayfun E.
Published: October 2010

We review and summarize our research activities in fluid–structure interaction (FSI) analysis of cerebral aneurysms using anatomically realistic geometry models based on medical images. Emphasis is placed on influencing factors in computational FSI, and their role and clinical implications are discussed in terms of the wall shear stress (WSS). The key factors are: (1) arterial and aneurysm geometries, (2) wall structure modeling, (3) blood pressure, (4) outflow conditions and (5) inflow conditions. Among these, we find the impact of the arterial and aneurysm geometries to be the most significant. Blood pressure also has a significant impact on the WSS distribution; a hypothetical hypertensive blood pressure condition could help estimate the rupture risk for an aneurysm. We find the other three factors to be minor compared with the arterial and aneurysm geometries and blood pressure, although the level of influence could be unique to the middle cerebral artery aneurysms that we have been focusing on in our studies. Copyright © 2010 John Wiley & Sons, Ltd.
Mafic dykes derived from Early Cretaceous depleted mantle beneath the Dabie orogenic belt: implications for changing lithosphere mantle beneath Eastern China
Authors: Chen Ling , Ma Chang Q. , Zhang Jin Y. , Mason Roger , Zhang Chao
Published: October 2010

SHRIMP zircon U–Pb geochronological, elemental and Sr–Nd isotopic data from Early Cretaceous mafic dykes in North Dabie orogenic belt elucidate a change of Mesozoic lithospheric mantle in eastern China. The dykes are predominantly dolerite with the major mineral assemblage clinopyroxene + hornblende + plagioclase and yield a SHRIMP zircon U–Pb age of 111.6 ± 5.3 Ma. They have a narrow range of SiO2 from 46.16% to 49.78%, and relative low concentrations of K2O (1.07−2.62%), Na2O (2.45−3.54%), Al2O3 (13.04−14.07%), and P2O5 (0.42−0.55%) but relatively high concentration of MgO (5.94–6.61%) with Mg# 52–54. All the samples are characterized by enrichment of large ion lithophile elements (LILE, e.g., Ba, Th) and high field strength elements (HFSE, e.g., Nb, Ti). (87Sr/86Sr)i ratios from 0.704 to 0.705, εNd values from 3.36 to 4.33 and mantle‐depletion Nd model ages (T2DM) in the range 0.56–0.64 Ga indicate that the magma of the Baiyashan mafic dykes was derived from a young depleted mantle source. This finding is different from previous research on mafic dykes in the age range 120–138 Ma that revealed enrichment of LILE and depletion of HFSE, high initial Sr isotopic ratios and negative εNd, value which represents an old enriched mantle source. Ours is the first report of the existence of Early Cretaceous depleted mantle in eastern China and it implies that changing of enriched mantle to depleted mantle occurred at ca. 112 Ma, associated with back‐arc extension which resulted from the subduction of the Palaeo‐Pacific Plate towards the Asian Continent. Copyright © 2010 John Wiley & Sons, Ltd.
Trilobites of the genus Dikelokephalina from Ordovician Gondwana and Avalonia
Authors: Fortey Richard A.
Published: October 2010

The trilobite Dikelokephalina is widespread across the Tremadocian Gondwana, Avalonia and Baltica palaeocontinents. The hitherto poorly known Anglo‐Welsh species D. furca (Salter, 1866) is revised on the basis of new and well‐preserved material. A new species, D. brenchleyi sp. nov., is described from the Anti‐Atlas, Morocco. The two species together provide a fuller understanding of the genus, and of the family, Dikelokephalinidae (Kobayashi, 1934), to which it has been assigned. Suggestions that this family may be a junior synonym of Hungaiidae (Raymond, 1924) are considered premature. D. brenchleyi sp. nov. apparently shows variation in mature segment number, a most unusual feature in post‐Cambrian trilobites. It is found in monospecific assemblages of large individuals which lack ventral median sutures, and a case is made that these individuals represent a mass gathering of individuals that have ceased to grow, for the purpose of fertilizing eggs, as happens in living Limulus. Copyright © 2010 John Wiley & Sons, Ltd.
Gist reasoning training in cognitively normal seniors
Authors: Anand Raksha , Chapman Sandra B. , Rackley Audette , Keebler Molly , Zientz Jennifer , Hart John
Published: October 2010

Objective

Cognitive impairment is a key factor that threatens functionality and quality of life in seniors. Given the projection that the population of individuals 65 years of age and older will double within the next 25 years, a critical need exists to identify and test effectiveness of protocols that target higher‐order cognitive skills such as gist reasoning to maximize cognitive capacity in later life.

Methods: This study examined the effects of eight hours of gist reasoning training in 26 cognitively normal seniors between the ages of 64‐85 years (M = 74.23, SD = 6.67).

Results

Findings suggest that top‐down strategy‐based gist reasoning training significantly improved abstraction ability, a skill relevant to everyday life, as well as generalized to untrained measures of executive function including concept abstraction, cognitive switching, and verbal fluency. Individuals with lower baseline ability to abstract gist showed the greatest gain in the target domain trained.

Conclusions

These findings highlight the potential value of engaging in cognitively challenging activities that involve gist reasoning, to strengthen and preserve cognitive capacity with aging. Copyright © 2010 John Wiley & Sons, Ltd.
Detection and characterization of single‐trial fMRI bold responses: Paradigm free mapping
Authors: Gaudes César Caballero , Petridou Natalia , Dryden Ian L. , Bai Li , Francis Susan T. , Gowland Penny A.
Published: October 2010

This work presents a novel method of mapping the brain's response to single stimuli in space and time without prior knowledge of the paradigm timing: paradigm free mapping (PFM). This method is based on deconvolution of the hemodynamic response from the voxel time series assuming a linear response and using a ridge‐regression algorithm. Statistical inference is performed by defining a spatio‐temporal t‐statistic and by controlling for multiple comparisons using the false discovery rate procedure. The methodology was validated on five subjects who performed self‐paced and visually cued finger tapping at 7 Tesla, with moderate (TR = 2 s) and high (TR = 0.4 s) temporal resolution. The results demonstrate that detection of single‐trial BOLD events is feasible without a priori information on the stimulus paradigm. The proposed method opens up the possibility of designing temporally unconstrained paradigms to study the cortical response to unpredictable mental events. Hum Brain Mapp, 2010. © 2010 Wiley‐Liss, Inc.
Two New Disulfated Triterpenoids from Zygophyllum fabago
Authors: Khan Saleha S. , Khan Afsar , Ahmed Amir , Ahmad Viqar U. , Farooq Umar , Arshad Saima , Bader Sadia , Zahoor Aqib , Siddiqui Imran N. , Sener Bilge , Erdemoglu Nurgun
Published: October 2010

From the aerial parts of Zygophyllum fabago, two new monosodium salts of sulfated derivatives of ursolic acid, along with two known quinovic acid glycosides were isolated. The structures of the new compounds were determined as (3β,4α)‐3,23,30‐trihydroxyurs‐20‐en‐28‐al 3,23‐di(sulfate) sodium salt (1 : 1) (1) and of (3β,4α)‐3,23,28‐trihydroxyurs‐20‐en‐30‐yl β‐D‐glucopyranoside 3,23‐di(sulfate) sodium salt (1 : 1) (2) with the molecular formula C30H47NaO10S2 and C36H59NaO15S2, respectively. The structures of the known compounds were 3‐O‐(2‐O‐sulfo‐β‐D‐quinovopyranosyl)quinovic acid 28‐β‐D‐glucopyranosyl ester (3) and 3‐O‐(β‐D‐glucopyranosyl)quinovic acid 28‐β‐D‐glucopyranosyl ester (4) (quinovic acid=(3β)‐3‐hydroxyurs‐12‐ene‐27,28‐dioic acid). The structures of all these compounds were determined by using 1D‐ and 2D‐NMR spectroscopic techniques.
Stereoselective Total Synthesis of Dodoneine
Authors: Chinnababu Baggu , Reddy Sudina Purushotham , Rao Chitturi Bhujanga , Rajesh Karuturi , Venkateswarlu Yenamandra
Published: October 2010

A simple and highly efficient stereoselective total synthesis of dodoneine (1), a naturally occurring bioactive 5,6‐dihydro‐2H‐pyran‐2‐one, was achieved. The synthesis involved Keck's asymmetric allylation, iodine‐induced electrophilic cyclization, and Grubbs' catalyzed ring‐closing metathesis as key steps.
Lewis Acids as Mild and Effective Catalysts for the Synthesis of 3,5‐Bis[(hetero)arylidene]piperidin‐4‐ones
Authors: Leonova Evgeniya , Makarov Mihail , Klemenkova Zinaida , Odinets Irina
Published: October 2010

The aldol‐crotonic condensation reactions of N‐alkyl‐ and NH‐piperidin‐4‐one derivatives with (hetero)aromatic aldehydes promoted by Lewis acids or bases were examined. This comparative study has revealed three effective catalytic systems based on Lewis acids, i.e., LiClO4 and MgBr2 (in the presence of tertiary amine), and BF3⋅Et2O, for the synthesis of N‐alkyl‐substituted 3,5‐bis(heteroarylidene)piperidin‐4‐ones, including those bearing acid‐ or base‐labile groups both in the (hetero)aromatic groups and in the alkyl substituent at the N‐atom. The highest reaction rate was observed for LiClO4‐mediated synthesis. Both MgBr2‐ and LiClO4‐mediated syntheses were inefficient in the case of NH‐piperidin‐4‐one, while BF3⋅Et2O provided the final compounds in high yields. This catalyst is especially advantageous as it allows simultaneous condensation and deprotection in the case of O‐protected piperidin‐4‐one.
A Novel Alkaloid from Melodinus henryi
Authors: Zhou Hua , He Hong‐Ping , Wang Yue‐Hu , Hao Xiao‐Jiang
Published: October 2010

The isolation and structure elucidation of a novel alkaloid, namely of the 14‐O‐ethyl‐substituted (3α,14α,16α)‐2,7‐secoeburnamine derivative 1 from the leaf of Melodinus henryi is reported. Ten known alkaloids were also isolated. Their structures were determined spectroscopically. The isolates were evaluated for their cytotoxicity.
Pubescone, a Novel 11(7→6)Abeo‐14‐norcarabrane Sesquiterpenoid from Siegesbeckia pubescens
Authors: Wang Rui , Liu Lei‐Lei , Shi Yan‐Ping
Published: October 2010

The phytochemical investigation of the aerial parts of Siegesbeckia pubescens L. yielded 16 sesquiterpenoids, including a novel 11(7→6)abeo‐14‐norcarabrane sesquiterpenoid, pubescone (1), and a new germacrane sesquiterpene, 5. The molecular structures of the isolated compounds were elucidated on the basis of extensive spectroscopic analysis, including 1D‐ and 2D‐NMR.
Labdane Diterpenes and Flavonoids from Leonurus japonicus
Authors: Seo Hyun Kyu , Kim Ju Sun , Kang Sam Sik
Published: October 2010

Chemical investigation of the aerial part of Leonurus japonicus led to the isolation and characterization of a new labdane‐type diterpene, named 3α‐acetoxy‐15‐O‐methylleopersin C (3), and a new acylated rutin derivative, named 2′′′‐syringylrutin (9), along with seven known compounds, including a labdane‐type diterpene and six flavonoids. The structures of the new compounds were established by spectroscopic methods.
The Effect of Fluoro Substitution upon the β‐Hairpin Fold of a β‐Tetrapeptide in Methanol
Authors: Bachmann Stephan , Jaun Bernhard , van Gunsteren Wilfred F. , Wang Dongqi
Published: October 2010

The importance of β‐peptides lies in their ability to mimic the conformational behavior of α‐peptides, even with a much shorter chain length, and in their resistance to proteases. To investigate the effect of substitution of β‐peptides on their dominant fold, we have carried out a molecular‐dynamics (MD) simulation study of two tetrapeptides, Ac‐(2R,3S)‐β2,3hVal(αMe)‐(2S)‐β2hPhe‐(R)‐β3hLys‐(2R,3S)‐β2,3‐Ala(αMe)‐NH2, differing in the substitution at the Cα of Phe2 (pepF with F, and pepH with H). Three simulations, unrestrained (UNRES), using 3J‐coupling biasing with local elevation in combination with either instantaneous (INS) or time‐averaging (AVE) NOE distance restraining, were carried out for each peptide. In the unrestrained simulations, we find three (pepF) and two (pepH) NOE distance bound violations of maximally 0.22 nm that involve the terminal residues. The restrained simulations match both the NOE distance bounds and 3J‐values derived from experiment. The fluorinated peptide shows a slightly larger conformational variability than the non‐fluorinated one.
Zooplankton Density Prediction in a Flood Lake (Pantanal – Brazil) Using Artificial Neural Networks
Authors: Fantin‐Cruz Ibraim , Pedrollo Olavo , Costa Bonecker Cláudia , da Motta‐Marques David , Loverde‐Oliveira Simoni
Published: October 2010

Ecologic relationships are usually non‐linear and highly complex. For this reason, artificial neural networks (ANN) were selected to model zooplankton density groups in the Coqueiro lake in the northern Pantanal of Brazil. The input layer used 11 limnological variables with 13 neurons in the hidden layer; the output layer consisted of three zooplankton groups. Samples were collected monthly between April 2002 and May 2003, at three different points of the lake, two of which were used for training the ANNs and the other for validation. The ANN model performed well at predicting the density of zooplankton groups (coefficients of determination r2were 0.88, 0.50 and 0.82 for rotifers, cladocerans and copepods, respectively). The comparison between models, and the ANN techniques used, demonstrated that zooplankton densities, observed one month previously, did not influence current densities, which were determined by limnological conditions in the lake. It was also shown that the processes that relate zooplankton to their environment remained stable during the study, while a model sensitivity analysis showed that the density dynamics of zooplankton groups in the Coqueiro lake were strongly influenced by availability of food (phytoplankton and detritus) and by variations in water‐level. It can be concluded from the study that ANNs are a powerful tool both for predicting zooplankton densities and for understanding their relationships with the environment. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Food Web and Trophic Basis of Production of the Benthic Macroinvertebrate Community of a Subtropical Stream (Yangtze River Basin, Middle China)
Authors: Wen Fangni , Jiang Jing , Deng Shan , Li Xiaoyu , Yan Yunjun
Published: October 2010

The food web of the benthic macroinvertebrate community of the Tanqigou Stream – a subtropical forested headwater stream of the Yangtze River basin – was investigated for the first time. The results indicated that the stream was mainly a detritus‐based system, with its functionality being highly dependent on allochthonous input of organic matter. Vascular plant detritus, filamentous algae, diatoms and fungi were also important food resources for the macroinvertebrate community in the stream. Temporal and spatial patterns of ingestion of four mayflies (which were the dominant species) demonstrated that there was little difference in feeding selection, but significant variations in ingestion patterns were observed, during different seasons and at different sampling sites. Nevertheless, the rates of ingestion of the four mayflies were generally stable and independent of the season or the site. The macroinvertebrate food web encompassed five basic food resources; four top predator species, and 27 intermediate non‐predator consumers. The predator‐prey ratio was 0.36; the total number of linkages 152; the trophic connectance 0.16; the maximum chain length three; and the mean chain length 2.21. A quantitative assessment of the energy flux along the major food web pathways indicated that organic matter pathways were mainly formed by weak linkages (36), which accounted for 60.31% of the total linkages (63) and that a few pathways accounted for most of the flow of organic matter. This suggests that Tanqigou Stream is similar to streams that are mainly dependant on detritus‐based‐ and allochthonous‐input of organic matter. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Competitive Influence of Zebra Mussel (Dreissena polymorpha) on Daphnia longispina Population Dynamics in the Presence of Cyanobacteria
Authors: Wojtal‐Frankiewicz Adrianna , Sieczko Anna , Izydorczyk Katarzyna , Jurczak Tomasz , Frankiewicz Piotr
Published: October 2010

The demographic response of Daphnia longispina to the presence of the competitive filter‐feeder zebra mussel (Dreissena polymorpha) was examined in a ten‐day laboratory experiment. The experiment was carried out in five replicates of four treatments corresponding to zooplankton and zebra mussels presence/absence combinations. Our experiment revealed a negative influence of zebra mussels on D. longispina population growth, suggesting low recruitment caused by high mortality at juvenile stages. We observed a smaller loss of phytoplankton biomass in mussel treatments than in the zooplankton treatment. Additionally, the concentration of microcystins was from 3.5 to 4.3 times higher in mussel treatments than in the zooplankton treatment. We also observed that Daphnia excreted significantly more ammonia than zebra mussels but less phosphate. The high amount of phosphate excreted by zebra mussels might have facilitated M. aeruginosa development and resulted in a greater cyanobacteria biomass in the mussel treatments. These results suggest a negative impact of invasive zebra mussels on a keystone filter‐feeding Daphnia spp. and a favourable effect of mussels on M. aeruginosa, by returning them back as pseudoceces, which may be important factors for the management of eutrophic freshwater ecosystems with cyanobacteria blooms. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enclosure Study on Phytoplankton Response to Stocking of Silver Carp (Hypophthalmichthys molitrix) in a Eutrophic Tropical Reservoir in South China
Authors: Xiao Lijuan , Ouyang Hao , Li Huiming , Chen Mianrun , Lin Qiuqi , Han Bo‐Ping
Published: October 2010

A 10‐week enclosure experiment was conducted in the dry season (October to December) to assess the impact of fish stocking on water quality and phytoplankton community at three stocking levels of silver carp (Hypophthalmichthys molitrix) (0, 16 and 50 g m–3) in a shallow, eutrophic tropical reservoir (Guangdong, South China). The nanophytoplankton (< 20 μm) accounted for 60 ± 5% of total biomass and Scenedesmus quadricauda was the predominant species (size: 16.5 ± 5 µm, relative biomass 27 ± 10%). Phytoplankton biomass was markedly suppressed in high fish stocking level and the grazing effect of silver carp on the nanoplankton was significant from the sixth week to the end of the experiment. The high fish density treatment significantly increased water transparency and somewhat reduced total phosphorus. Indirect effects of silver carp on the phytoplankton community involved excretion of nitrogen that favored small species of Chlorophyta. Colonial Cyanobacteria were reduced in the high fish treatment, but enhanced in the low fish treatment.

Our results suggest that the widespread practice of harvesting fish from October to December in reservoirs of South China releases phytoplankton from consumption by filter‐feeding fish, and consequently prompts algal blooms. Conversely, harvesting fish just before monsoon, around the time of restocking with small fish, would make more sense since no interruption in grazing pressure would occur. This would help to control excessive phytoplankton biomass just before monsoon. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Three‐dimensional T1 mapping of the mouse heart using variable flip angle steady‐state MR imaging
Authors: Coolen Bram F. , Geelen Tessa , Paulis Leonie E. M. , Nauerth Arno , Nicolay Klaas , Strijkers Gustav J.
Published: October 2010

Cardiac MR T1 mapping is a promising quantitative imaging tool for the diagnosis and evaluation of cardiomyopathy. Here, we present a new preclinical cardiac MRI method enabling three‐dimensional T1 mapping of the mouse heart. The method is based on a variable flip angle analysis of steady‐state MR imaging data. A retrospectively triggered three‐dimensional FLASH (fast low‐angle shot) sequence (3D IntraGate) enables a constant repetition time and maintains steady‐state conditions. 3D T1 mapping of the complete mouse heart could be achieved in 20 min. High‐quality, bright‐blood T1 maps were obtained with homogeneous T1 values (1764 ± 172 ms) throughout the myocardium. The repeatability coefficient of R1 (1/T1) in a specific region of the mouse heart was between 0.14 and 0.20 s−1, depending on the number of flip angles. The feasibility for detecting regional differences in ΔR1 was shown with pre‐ and post‐contrast T1 mapping in mice with surgically induced myocardial infarction, for which ΔR1 values up to 0.83 s−1 were found in the infarct zone. The sequence was also investigated in black‐blood mode, which, interestingly, showed a strong decrease in the apparent mean T1 of healthy myocardium (905 ± 110 ms). This study shows that 3D T1 mapping in the mouse heart is feasible and can be used to monitor regional changes in myocardial T1, particularly in relation to pathology and in contrast‐enhanced experiments to estimate local concentrations of (targeted) contrast agent. Copyright © 2010 John Wiley & Sons, Ltd.
Delineation of substrate selection and anaplerosis in tricarboxylic acid cycle of the heart by 13C NMR spectroscopy and mass spectrometry
Authors: Li Wei , Bian Fang , Chaudhuri Priyanjana , Mao Xian , Brunengraber Henri , Yu Xin
Published: October 2010

13C NMR and mass spectrometry (MS) provide complementary information regarding the 13C labeling of intermediary metabolites. Currently, these two techniques are rarely used together because of the complexity of modeling the distribution of both positional and mass isotopomers. In this study, we developed a matrix‐based model for the assessment of 13C label distribution in the tricarboxylic acid cycle and related metabolites. The model was applied to the analysis of NMR‐ and MS‐measured 13C isotopomers for quantification of substrate utilization and anaplerotic fluxes in isolated perfused rat hearts. NMR and MS data were acquired from two groups of rat hearts perfused with substrates in complementary labeling patterns, i.e. the 13C‐PAL + GLC group (0.6 mM [13C16]palmitate + 5.5 mM glucose) and the PAL + 13C‐GLC group (0.6 mM palmitate + 5.5 mM [13C6]glucose). Relative flux parameters were obtained by fitting the model to the NMR data, MS data and their combination, respectively. Our results suggest that, although both NMR and MS can provide accurate quantification of substrate selection in oxidative metabolism, the accuracy of estimation of anaplerotic fluxes relies on the combination of these two experimental methods. Copyright © 2010 John Wiley & Sons, Ltd.
High‐field MRI of single histological slices using an inductively coupled, self‐resonant microcoil: application to ex vivo samples of patients with Alzheimer's disease
Authors: Nabuurs Rob J. A. , Hegeman Ingrid , Natté Remco , van Duinen Sjoerd G. , van Buchem Mark A. , van der Weerd Louise , Webb Andrew G.
Published: October 2010

A simple inductively coupled microcoil has been designed to image tissue samples placed on a microscope slide, samples which can subsequently be stained histologically. As the exact same tissue is used for MRI and histology, the two data sets can be compared without the need for complicated image registration techniques. The design can be integrated into any MRI system using existing commercial hardware. Compared with a commercial 25‐mm‐diameter birdcage, the signal‐to‐noise ratio was increased by a factor of 3.8, corresponding to an approximate 15‐fold reduction in the data acquisition time. An example is shown of ex vivo samples from patients with Alzheimer's disease, in which the coregistration of highly sensitive iron staining and amyloid‐β deposits is confirmed. Copyright © 2010 John Wiley & Sons, Ltd.
Evaluation of a quantitative blood oxygenation level‐dependent (qBOLD) approach to map local blood oxygen saturation
Authors: Christen Thomas , Lemasson Benjamin , Pannetier Nicolas , Farion Régine , Segebarth Christoph , Rémy Chantal , Barbier Emmanuel L.
Published: October 2010

Blood oxygen saturation (SO2) is a promising parameter for the assessment of brain tissue viability in numerous pathologies. Quantitative blood oxygenation level‐dependent (qBOLD)‐like approaches allow the estimation of SO2 by modelling the contribution of deoxyhaemoglobin to the MR signal decay. These methods require a high signal‐to‐noise ratio to obtain accurate maps through fitting procedures. In this article, we present a version of the qBOLD method at long TE taking into account separate estimates of T2, total blood volume fraction (BVf) and magnetic field inhomogeneities. Our approach was applied to the brains of 13 healthy rats under normoxia, hyperoxia and hypoxia. MR estimates of local SO2 (MR_LSO2) were compared with measurements obtained from blood gas analysis. A very good correlation (R2 = 0.89) was found between brain MR_LSO2 and sagittal sinus SO2. Copyright © 2010 John Wiley & Sons, Ltd.
Comparative determination of energy production rates and mitochondrial function using different 31P MRS quantitative methods in sedentary and trained subjects
Authors: Layec Gwenael , Bringard Aurélien , Le Fur Yann , Vilmen Christophe , Micallef Jean‐Paul , Perrey Stéphane , Cozzone Patrick J. , Bendahan David
Published: October 2010

Muscle energetics has been largely and quantitatively investigated using 31P MRS. Various methods have been used to estimate the corresponding rate of oxidative ATP synthesis (ATPox); however, potential differences among methods have not been investigated. In this study, we aimed to compare the rates of ATP production and energy cost in two groups of subjects with different training status using four different methods: indirect method (method 1), ADP control model (method 2) and phosphate potential control model (method 3). Method 4 was a modified version of method 3 with the introduction of a correction factor allowing for similar values to be obtained for the end‐exercise oxidative ATP synthesis rate inferred from exercise measurements and the initial recovery phosphocreatine resynthesis rate. Seven sedentary and seven endurance‐trained subjects performed a dynamic standardised rest–exercise–recovery protocol. We quantified the rates of ATPox and anaerobic ATP synthesis (ATPana) using 31P MRS data recorded at 1.5 T. The rates of ATPox over the entire exercise session were independent of the method used, except for method 4 which provided significantly higher values in both groups (p < 0.01). In addition, methods 1–3 were cross‐correlated, thereby confirming their statistical agreement. The rate of ATPana was significantly higher with method 1 (p < 0.01) and lower with method 4 (p < 0.01). As a result of the higher rate of ATPox, EC (method 4) calculated over the entire exercise session was higher and initial EC (method 1) was lower in both groups compared with the other methods. We showed in this study that the rate of ATPox was independent of the calculation method, as long as no corrections (method 4) were performed. In contrast, results related to the rates of ATPana were strongly affected by the calculation method and, more exactly, by the estimation of protons generated by ATPox. Although the absolute EC values differed between the methods, within‐ or between‐subject comparisons are still valid given the tight relationships between them. Copyright © 2010 John Wiley & Sons, Ltd.
Preliminary observations of increased diffusional kurtosis in human brain following recent cerebral infarction
Authors: Jensen Jens H. , Falangola Maria F. , Hu Caixia , Tabesh Ali , Rapalino Otto , Lo Calvin , Helpern Joseph A.
Published: October 2010

By application of the MRI method of diffusional kurtosis imaging, a substantially increased diffusional kurtosis was observed within the cerebral ischemic lesions of three stroke subjects, 13–26 h following the onset of symptoms. This increase is interpreted as probably reflecting a higher degree of diffusional heterogeneity in the lesions when compared with normal‐appearing contralateral tissue. In addition, for two of the subjects with white matter infarcts, the increase had a strong fiber tract orientational dependence. It is proposed that this effect is consistent with a large drop in the intra‐axonal diffusivity, possibly related to either axonal varicosities or alterations associated with the endoplasmic reticulum. Copyright © 2010 John Wiley & Sons, Ltd.
Obsessive–compulsive personality disorder: a review of current empirical findings
Authors: de Reus Rob J.M. , Emmelkamp Paul M.G.
Published: October 2010

The aim of this article is to review the literature on aetiology, epidemiology and course, assessment and treatment of the obsessive–compulsive personality disorder (OCPD). OCPD is a rather prevalent personality disorder, being one of the most prevalent personality disorders in the general population. OCPD is associated with moderate Axis I and Axis II co‐occurrence and functional impairment is stable over time but generally mild. There is some evidence that the economic burden of OCPD may be considerable. Psychological treatment studies on patients with OCPD are rare, consisting of a few case studies and two open studies. Only one randomized controlled study on pharmacotherapy and no controlled study on psychological treatment directly focusing on OCPD as primary complaint have been reported. Finally, future areas of research are discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Global strategy for the diagnosis and management of asthma in children 5 years and younger
Authors: Pedersen Soren Erik , Hurd Suzanne S. , Lemanske Robert F. , Becker Allan , Zar Heather J. , Sly Peter D. , Soto‐Quiroz Manuel , Wong Gary , Bateman Eric D.
Published: October 2010

Asthma is the most common chronic disease of childhood and the leading cause of childhood morbidity from chronic disease as measured by school absences, emergency department visits, and hospitalions1. During the past two decades, many scientific advances have improved our understanding of asthma and our ability to manage and control it effectively. However, in children 5 years and younger, the clinical symptoms of asthma are variable and non‐specific. Furthermore, neither airflow limitation nor airway inflammation, the main pathologic hallmarks of the condition, can be assessed routinely in this age group. For this reason, to aid in the diagnosis of asthma in young children, a symptoms‐only descriptive approach that includes the definition of various wheezing phenotypes has been recommended2. In 1993, the Global Initiative for Asthma (GINA) was implemented to develop a network of individuals, organizations, and public health officials to disseminate information about the care of patients with asthma while at the same time assuring a mechanism to incorporate the results of scientific investigations into asthma care. Since then, GINA has developed and regularly revised a Global Strategy for Asthma Management and Prevention. Publications based on the Global Strategy for Asthma Management and Prevention have been translated into many different languages to promote international collaboration and dissemination of information.

In this report, Global Strategy for Asthma Management and Prevention in Children 5 Years and Younger, an effort has been made to present the special challenges that must be taken into account in managing asthma in children during the first 5 years of life, including difficulties with diagnosis, the efficacy and safety of drugs and drug delivery systems, and the lack of data on new therapies. Approaches to these issues will vary among populations in the world based on socioeconomic conditions, genetic diversity, cultural beliefs, and differences in healthcare access and delivery. Patients in this age group are often managed by pediatricians and general practitioners routinely faced with a wide variety of issues related to childhood diseases. Pediatr Pulmonol. 2011; 46:1–17. © 2010 Wiley‐Liss, Inc.
Iron and CF‐related anemia: Expanding clinical and biochemical relationships
Authors: Gifford A.H. , Miller S.D. , Jackson B.P. , Hampton T.H. , O'Toole G.A. , Stanton B.A. , Parker H.W.
Published: October 2010

Introduction

This cross‐sectional study was conducted to assess the relationship between iron levels in the plasma and sputum of cystic fibrosis (CF) patients.

Methods

Demographic, clinical, and iron‐related laboratory data were prospectively obtained from 25 patients with stable clinical features and 14 patients with worsened clinical features since their most recent evaluations.

Results

Compared to patients with stable clinical features, those who experienced clinical deterioration demonstrated significantly worse lung function and were more frequently malnourished and diabetic. Members of the latter group were also significantly more hypoferremic and had higher sputum iron content than patients with stable clinical features. No significant correlation was found between plasma and sputum iron levels when the groups were analyzed together and separately.

Conclusions

Sputum iron content does not correlate with iron‐related hematologic tests. Hypoferremia is common in CF and correlates with poor lung function and overall health. Pediatr. Pulmonol. 2011; 46:160–165. © 2011 Wiley‐Liss, Inc.
Airway hyperresponsiveness to methacholine in 7‐year‐old children: sensitivity and specificity for pediatric allergist‐diagnosed asthma
Authors: Carlsten Chris , Dimich‐Ward Helen , Ferguson Alexander , Becker Allan , DyBuncio Anne , Chan‐Yeung Moira
Published: October 2010

Background:

The operating characteristics of PC20 values used as cut‐offs to define airway hyperresponsiveness, as it informs the diagnosis of asthma in children, are poorly understood. We examine data from a unique cohort to inform this concern.

Objective:

Determine the sensitivity and specificity of incremental PC20 cut‐offs for allergist‐diagnosed asthma.

Methods:

Airway reactivity at age 7 was assessed in children within a birth cohort at high risk for asthma; PC20 for methacholine was determined by standard technique including interpolation. The diagnosis of asthma was considered by the pediatric allergist without knowledge of the methacholine challenge results. Sensitivity and specificity were calculated using a cross‐tabulation of asthma diagnosis with incremental PC20 cut‐off values, from 1.0 to 8.0 mg/ml, and plotted as receiver operator characteristic (ROC) curves. The “optimal” cut‐off was defined as that PC20 conferring maximal value for sensitivity plus specificity while the “balanced” cut‐off was defined as that PC20 at which sensitivity and specificity were most equal.

Results:

70/348 children (20.1%) were diagnosed with asthma. The optimal and balanced PC20 cut‐offs, both for all children and for females alone, were respectively 3 mg/ml (sensitivity 80.0%, specificity 49.1%) and 2 mg/ml (sensitivity 63.1%, specificity 64.7%). For males alone, the “optimal” and “balanced” PC20 cut‐offs were both 2 mg/ml.

Conclusion:

For this cohort of 7‐year olds at high risk for asthma, methacholine challenge testing using a cut‐off value of PC20 3 mg/ml conferred the maximal sum of specificity plus sensitivity. For contexts in which higher sensitivity or specificity is desired, other cut‐offs may be preferred. Pediatr. Pulmonol. 2011; 46:175–178. © 2011 Wiley‐Liss, Inc.
Use of a lung model to assess mechanical in‐exsufflator therapy in infants with tracheostomy
Authors: Striegl Amanda M. , Redding Gregory J. , DiBlasi Robert , Crotwell Dave , Salyer John , Carter Edward R.
Published: October 2010

Background

The mechanical in‐exsufflator (MIE) is commonly used to augment cough in patients with neuromuscular disease from infancy to adulthood. Little is known about the alveolar pressures, lung volumes, and expiratory flow rates generated by the MIE when used via tracheostomy tube in infants and children.

Methods

A high‐fidelity mechanical lung model was programmed to simulate infants with tracheostomy tubes. Generated pressures, volumes, and expiratory flows using the MIE device at variable insufflation/exsufflation pressures and times were recorded. The primary measure of interest was maximal expiratory flow (MEF).

Results

Pressure equilibration across the tracheostomy tube did not occur with insufflation time <1 sec. Longer insufflation time significantly increased measured alveolar pressures, lung volume, and MEF until TLC was reached. Longer exsufflation time did not significantly increase MEF. Higher insufflation pressures resulted in greater lung volumes, with >70% vital capacity attained at insufflation pressures as low as 20 cmH2O. Though higher insufflation pressures resulted in increased expiratory flow rates, more negative exsufflation pressure had a greater absolute impact on MEF.

Conclusions

Using the MIE via tracheostomy tube in an infant lung model, we found that an insufflation time of >1 sec is required for equilibration of insufflation pressure and alveolar pressure. Longer exsufflation time does not significantly alter MEF. Higher insufflation and exsufflation pressures both increased MEF, but greater exsufflation pressure had more substantial impact. Pediatr Pulmonol. 2011; 46:211–217. © 2011 Wiley‐Liss, Inc.