bluuebunny/crossref_metadata_2025 huggingface dataset:
Ungulate preference for burned patches reveals strength of fire–grazing interaction
Authors: Allred Brady W. , Fuhlendorf Samuel D. , Engle David M. , Elmore R. Dwayne
Published: August 2011

The interactions between fire and grazing are widespread throughout fire‐dependent landscapes. The utilization of burned areas by grazing animals establishes the fire–grazing interaction, but the preference for recently burned areas relative to other influences (water, topography, etc.) is unknown. In this study, we determine the strength of the fire–grazing interaction by quantifying the influence of fire on ungulate site selection. We compare the preference for recently burned patches relative to the influence of other environmental factors that contribute to site selection; compare that preference between native and introduced ungulates; test relationships between area burned and herbivore preference; and determine forage quality and quantity as mechanisms of site selection. We used two large ungulate species at two grassland locations within the southern Great Plains, USA. At each location, spatially distinct patches were burned within larger areas through time, allowing animals to select among burned and unburned areas. Using fine scale ungulate location data, we estimated resource selection functions to examine environmental factors in site selection. Ungulates preferred recently burned areas and avoided areas with greater time since fire, regardless of the size of landscape, herbivore species, or proportion of area burned. Forage quality was inversely related to time since fire, while forage quantity was positively related. We show that fire is an important component of large ungulate behavior with a strong influence on site selection that drives the fire–grazing interaction. This interaction is an ecosystem process that supersedes fire and grazing as separate factors, shaping grassland landscapes. Inclusion of the fire–grazing interaction into ecological studies and conservation practices of fire‐prone systems will aid in better understanding and managing these systems.
Formation and Reactivity of a Biomimetic Hydroperoxocopper(II) Cryptate
Authors: Chaloner Laura , Askari Mohammad S. , Kutteh Adrian , Schindler Siegfried , Ottenwaelder Xavier
Published: August 2011

Copper(II)‐hydroperoxo species are proposed as key intermediates in the catalytic cycles of copper‐monooxygenase enzymes that perform C–H bond hydroxylation. Herein we report on the oxidation chemistry of a copper(II) complex with a coordinating cryptand based on a peralkylated tetradentate tris(2‐aminoethyl)amine (tren) moiety. X‐ray crystallography of the copper(II) acetate complex of this cryptand revealed that the copper(II) ion is in a square‐pyramidal environment, with the cryptand acting only as a tridentate ligand. This geometry is conserved in solution and likely results from restraints imposed by the semi‐rigid cryptand. Reaction of this complex with basic hydrogen peroxide in methanol led to the decomposition of the complex with an oxygen‐atom transfer to the ligand, as evidenced by mass spectrometry analysis after reaction and demetallation. Low‐temperature stopped‐flow experiments (down to –90 °C) support the formation of a copper(II)‐hydroperoxo intermediate, CuOOH, before ligand oxygenation occurs. It is proposed that this intermediate performs the oxygen‐atom transfer to a weak benzylic C–H bond of the cryptand, thereby mimicking the behavior of dopamine‐β‐hydroxylase.
Chiral Diamine Bis(phenolate) TiIV and ZrIV Complexes – Synthesis, Structures and Reactivity
Authors: Barroso Sónia , Adão Pedro , Duarte M. Teresa , Meetsma Auke , Pessoa João Costa , Bouwkamp Marco W. , Martins Ana M.
Published: August 2011

Neutral and cationic titanium and zirconium diamine bis(phenolate) complexes supported by chiral ligands L1 and L2 are described [L1 = (R)‐6,6′‐{1‐(dimethylamino)propan‐2‐ylazanediyl}bis(methylene)‐bis(2,4‐di‐tert‐butylphenolate);L2 = (S)‐6,6′‐{(1‐ethylpyrrolidin‐2‐yl)methylazanediyl}bis(methylene)‐bis(2,4‐di‐tert‐butylphenolate)]. Complexes[TiL(OiPr)2] [L = L1 (1), L2 (2)], [TiL2X(OiPr)] [X = Cl (3), CH2Ph (4)], [TiL1(CH2Ph)2] (5), [ZrLCl2] [L = L1 (6), L2 (7)] and [ZrL(CH2Ph)2] [L = L1 (8), L2 (9)] are C1‐symmetric species readily prepared in moderate to high yields. Cationic compounds were obtained from complexes 5, 8 and 9 through reactions with B(C6F5)3. The monocationic species reveal the η2‐binding character of the benzyl groups and noncoordinated [B(C6F5)3(CH2Ph)]–. Complexes 5–9 were tested in the polymerization of ethylene and propylene upon activation with modified methylaluminoxane (MMAO), B(C6F5)3 or [NHMe2Ph]+ as cocatalysts. The [ZrL1Cl2]/MMAO and [ZrL1(CH2Ph)2]/B(C6F5)3 systems revealed high activities in the polymerization of propylene (2.1 × 103 and 1.5 × 103 gpol mmolcat–1 h–1, respectively), leading to atatic polypropylene, whereas the titanium complexes showed no activity.
Substituent‐Controlled Electrocyclization of 2,4‐Dienones: Synthesis of 2,3,6‐Trisubstituted 2H‐Pyran‐5‐carboxylates and Their Transformations
Authors: Peng Wei , Hirabaru Toshiaki , Kawafuchi Hiroyuki , Inokuchi Tsutomu
Published: August 2011

A facile access to 2,3,6‐trisubstituted 2H‐pyran‐5‐carboxylates is developed by employing 2‐alkyl‐2‐enals as reactants with acetoacetates. The reaction involves Knoevenagel condensation followed by a 6π‐electrocyclization, in which the presence of the C2 alkyl substituent in the enals favors the formation of (E)‐Knoevenagel adducts for the ensuing electrocyclization. The resulting 2H‐pyrans are hydrogenated to form 3,4‐dihydro‐2H‐pyrans and converted into the endoperoxides by singlet‐oxygen cycloaddition.
Three‐dimensional vortex simulation of unsteady flow in hydraulic turbines
Authors: Zhu Baoshan , Wang Hong , Wang Longbu , Cao Shuliang
Published: August 2011

On the basis of the Helmholtz decomposition, a grid‐free numerical scheme is provided for the solution of unsteady flow in hydraulic turbines. The Lagrangian vortex method is utilized to evaluate the convection and stretch of the vorticity, and the BEM is used to solve the Neumann problem to define the potential flow. The no‐slip boundary condition is satisfied by generating vortex sticks at the solid surface. A semi‐analytical regularization technique is applied to evaluate the singular boundary surface integrals of the potential velocity and its gradients accurately. The fast multipole method was extended to evaluate the velocity and velocity gradients induced by the discretized vortex blobs in the Lagrangian vortex method. The successful simulation for the unsteady flow through a hydraulic turbine's runner has manifested the effectiveness of the proposed method. Copyright © 2011 John Wiley & Sons, Ltd.
Semi‐automatic porting of a large‐scale CFD code to multi‐graphics processing unit clusters
Authors: Corrigan Andrew , Löhner Rainald
Published: August 2011

A typical large‐scale CFD code based on adaptive, edge‐based finite‐element formulations for the solution of compressible and incompressible flow is taken as a test bed to port such codes to graphics hardware (graphics processing units, GPUs) using semi‐automatic techniques. In previous work, a GPU version of this code was presented, in which, for many run configurations, all mesh‐sized loops required throughout time stepping were ported. This approach simultaneously achieves the fine‐grained parallelism required to fully exploit the capabilities of many‐core GPUs, completely avoids the crippling bottleneck of GPU–CPU data transfer, and uses a transposed memory layout to meet the distinct memory access requirements posed by GPUs. The present work describes the next step of this porting effort, namely to integrate GPU‐based, fine‐grained parallelism with Message‐Passing‐Interface‐based, coarse‐grained parallelism, in order to achieve a code capable of running on multi‐GPU clusters. This is carried out in a semi‐automated fashion: the existing Fortran–Message Passing Interface code is preserved, with the translator inserting data transfer calls as required. Performance benchmarks indicate up to a factor of 2 performance advantage of the NVIDIA Tesla M2050 GPU (Santa Clara, CA, USA) over the six‐core Intel Xeon X5670 CPU (Santa Clara, CA, USA), for certain run configurations. In addition, good scalability is observed when running across multiple GPUs. The approach should be of general interest, as how best to run on GPUs is being presently considered for many so‐called legacy codes. Copyright © 2011 John Wiley & Sons, Ltd.
Dynamics of snow ablation in a small Alpine catchment observed by repeated terrestrial laser scans
Authors: Egli Luca , Jonas Tobias , Grünewald Thomas , Schirmer Michael , Burlando Paolo
Published: August 2011

The spatio‐temporal distribution of snow in a catchment during ablation reflects changes in the total amount of snow water equivalent and is thus a key parameter for the estimation of melt water run‐off. This study explores possible rules behind the spatial variability of snow depth during the ablation season in a small Alpine catchment with complex topography. The snow depth observations are based on more than 160 000 terrestrial laser scanner data points with a spatial resolution of 1 m, which were obtained from 11 scanning campaigns of two consecutive ablation seasons.

The analysis suggests that for estimating cumulative snow melt dynamics from the catchment investigated, assessing the initial snow distribution prior to the melt season is more important than addressing spatial differences in the melt behaviour. Snow volume and snow‐covered area could be predicted well using a conceptual melt model assuming spatially uniform melt rates. However, accurate results were only obtained if the model was initialized with a pre‐melt snow distribution that reflected measured mean and standard deviation. Using stratified melt rates on the other hand did not improve the model results. At least for sites with similar meteorological and topographical conditions, the model approach presented here comprises an efficient way to estimate snow depletion dynamics, especially if persistent snow accumulation pattern between years facilitate the characterization of the initial snow distribution prior to the melt. Copyright © 2011 John Wiley & Sons, Ltd.
LigDockCSA: Protein–ligand docking using conformational space annealing
Authors: Shin Woong‐Hee , Heo Lim , Lee Juyong , Ko Junsu , Seok Chaok , Lee Jooyoung
Published: August 2011

Protein–ligand docking techniques are one of the essential tools for structure‐based drug design. Two major components of a successful docking program are an efficient search method and an accurate scoring function. In this work, a new docking method called LigDockCSA is developed by using a powerful global optimization technique, conformational space annealing (CSA), and a scoring function that combines the AutoDock energy and the piecewise linear potential (PLP) torsion energy. It is shown that the CSA search method can find lower energy binding poses than the Lamarckian genetic algorithm of AutoDock. However, lower‐energy solutions CSA produced with the AutoDock energy were often less native‐like. The loophole in the AutoDock energy was fixed by adding a torsional energy term, and the CSA search on the refined energy function is shown to improve the docking performance. The performance of LigDockCSA was tested on the Astex diverse set which consists of 85 protein–ligand complexes. LigDockCSA finds the best scoring poses within 2 Å root‐mean‐square deviation (RMSD) from the native structures for 84.7% of the test cases, compared to 81.7% for AutoDock and 80.5% for GOLD. The results improve further to 89.4% by incorporating the conformational entropy. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
QSPR study of Setschenow constants of organic compounds using MLR, ANN, and SVM analyses
Authors: Xu Jie , Wang Lei , Wang Luoxin , Shen Xiaolin , Xu Weilin
Published: August 2011

A quantitative structure‐property relationship (QSPR) study was performed for the prediction of the Setschenow constants (Ksalt) by sodium chloride of organic compounds. The entire set of 101 compounds was randomly divided into a training set of 71 compounds and a test set of 30 compounds. Multiple linear regression, artificial neural network (ANN), and support vector machine (SVM) were utilized to build the linear and nonlinear QSPR models, respectively. The obtained models with four descriptors involved show good predictive ability. The linear model fits the training set with R2 = 0.8680, while ANN and SVM higher values of R2 = 0.8898 and 0.9302, respectively. The validation results through the test set indicate that the proposed models are robust and satisfactory. The QSPR study suggests that the molecular lipophilicity is closely related to the Setschenow constants. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
INEQUALITY IN THE MONETARY AND FUNCTIONINGS SPACES: THE CASE OF PERU UNDER THE FIRST GARCIA GOVERNMENT (1985–1990)
Authors: Burchi Francesco , Passacantilli Andrea
Published: August 2011

In this article, we analyze inequality changes in Peru under the first Garcia government (1985–1990). Our findings indicate that stability in consumption inequality and a substantial decline in wealth inequality were achieved, probably thanks to the government's demand‐led policies, despite their deleterious effects on other macroeconomic indicators. The following analysis reveals that inequality in most functionings, including overall well‐being, diminished, as did geographical disparities. We thus offer here (i) a methodological contribution to the debate on inequality, stressing the need to go beyond consumption/income inequality if one wants to track inequality changes across time, and (ii) a contribution to the debate about the socioeconomic situation in Peru between 1985 and 1990. Copyright © 2011 John Wiley & Sons, Ltd.
Characterizing variability in in vivo Raman spectroscopic properties of different anatomical sites of normal tissue in the oral cavity
Authors: Bergholt Mads Sylvest , Zheng Wei , Huang Zhiwei
Published: August 2011

Raman spectroscopy is an inelastic light scattering technique that is capable of probing biochemical and biomolecular structures and conformations of tissue. This study aims to characterize the in vivo Raman spectroscopic properties of different normal oral tissues in the fingerprint region (800–1800 cm−1) and to assess distinctive biochemical variations of different anatomical regions in the oral cavity. A specially designed fiber‐optic Raman probe with a ball lens was utilized for real‐time, in vivo Raman measurements of various oral tissue sites (i.e. inner lip, attached gingiva, floor, dorsal tongue, ventral tongue, hard palate, soft palate, and buccal). The semiquantitative non‐negativity‐constrained least squares minimization fitting of reference biochemicals representing oral tissue constituents (i.e. hydroxyapatite, keratin, collagen, DNA, and oleic acid) and partial least squares‐discriminant analysis (PLS‐DA) were employed to assess the significance of inter‐anatomical variability. A total of 402 high‐quality in vivo oral Raman spectra were acquired from 20 subjects. The histological characteristics of different oral tissues were found to have influence on the in vivo Raman spectra and could be grossly divided into three major clusterings: (1) buccal, inner lip, and soft palate; (2) dorsal, ventral tongue, and floor; (3) gingiva and hard palate. The PLS‐DA multiclass algorithms were able to identify different tissue sites with varying accuracies (inner lip 83.1%, attached gingiva 91.3%, floor 86.1%, dorsal tongue 88.8%, ventral tongue 83.1%, hard palate 87.6%, soft palate 83.3%, and buccal mucosa 85.3%), bringing out the similarities among different oral tissues at the biomolecular level. This study discloses that inter‐anatomical variability is significant and should be considered as an important parameter in the interpretation and rendering of Raman diagnostic algorithms for oral tissue diagnosis and characterization. Copyright © 2011 John Wiley & Sons, Ltd.
Effect of high‐energy light‐ion irradiation on SI‐GaAs and GaAs:Cr as observed by Raman spectroscopy
Authors: Mishra Shramana , Kabiraj D. , Roy Anushree , Ghosh Subhasis
Published: August 2011

The structural evolutions of high‐energy (50 MeV) lithium ion (Li3+) irradiated undoped semi‐insulating GaAs (SI‐GaAs) and chromium‐doped SI‐GaAs (GaAs:Cr) were investigated by Raman measurements. It is shown that high‐energy Li3+ irradiation causes amorphization beyond a fluence of 3 × 1013 ions/cm2 in undoped SI‐GaAs. Interestingly, the same fluence of ions does not seem to affect the crystallinity in GaAs:Cr appreciably. The effect of ion irradiation on the change in lattice ordering and anharmonicity of the phonon modes of undoped SI‐GaAs and GaAs:Cr is also compared. Copyright © 2011 John Wiley & Sons, Ltd.
Environmental conditions affect semolina quality in durum wheat (Triticum turgidum ssp. durum L.) cultivars with different gluten strength and gluten protein composition
Authors: Fois Simonetta , Schlichting Linda , Marchylo Brian , Dexter James , Motzo Rosella , Giunta Francesco
Published: August 2011

BACKGROUND: Sowing time may impact semolina and pasta cooking quality by changing the environmental conditions during grain filling. The effect of an optimum and a delayed sowing time on semolina quality was studied by comparing six cultivars under irrigation, in order to isolate temperature from drought effects.

RESULTS: Protein content was higher in the old cultivars and in the late sowings, according to the number of days with temperature between 30 and 40 °C during ripening. Gluten index increased as temperature rose to a threshold of about 30 °C, then decreased under higher temperatures. Mixograph parameters were less sensitive to high temperatures. Gliadin:glutenin correlated with gluten strength. Spaghetti firmness and protein content were positively correlated independently of sowing date. Cultivars Trinakria and Cappelli had the highest spaghetti firmness (900 and 828 g).

CONCLUSIONS: Late sowings may represent a way of increasing pasta cooking quality whenever they place grain filling under thermal conditions able to increase protein percentage, although the accompanying decrease in yield may represent a drawback in environments prone to drought stress during ripening. The lower protein percentages of modern durum wheat cultivars under conventional sowing times results in a lower pasta cooking quality despite higher gluten strength. Published 2011 by John Wiley & Sons, Ltd.
Antioxidant activities and functional properties of grass carp (Ctenopharyngodon idellus) protein hydrolysates
Authors: Li Xue , Luo Yongkang , Shen Huixing , You Juan
Published: August 2011

BACKGROUND: Grass carp, with an annual production exceeding 4 × 106 t in China in 2009, has not been developed into a high‐value product. In this study the antioxidant activities and functional properties of grass carp protein hydrolysates prepared with Alcalase 2.4L (HA) and papain (HP) were investigated. The hydrolysate with strongest radical‐scavenging activity and reducing power was assessed further for changes in its antioxidant activity during simulated gastrointestinal digestion.

RESULTS: As the degree of hydrolysis (DH) increased, the metal‐chelating activity of both HA and HP increased while their reducing power and 1,1‐diphenyl‐2‐picrylhydrazyl radical (DPPH•)‐scavenging activity decreased (P < 0.05). At the same DH, HP possessed higher DPPH•‐scavenging activity and reducing power than HA (P < 0.05). The metal‐chelating activity of HP with 10% DH was significantly increased after in vitro gastrointestinal metabolism (P < 0.05). Regarding their functional properties, all hydrolysates were more than 81% soluble over a wide range of pH (3–8). At the same DH, HP showed higher emulsion activity index but lower solubility and foaming capacity than HA.

CONCLUSION: Grass carp protein hydrolysates showed high solubility over a wide pH range and could be used as natural antioxidants in food systems. Copyright © 2011 Society of Chemical Industry
The prognostic significance of tumor laterality in patients with esophageal squamous cell carcinoma
Authors: Mine Shinji , Yamada Kazuhiko , Grabsch Heike , Sano Takeshi , Ishiyama Akiyoshi , Hirasawa Toshiaki , Yamamoto Noriko , Hiki Naoki , Yamaguchi Toshiharu
Published: August 2011

Background

It has been shown that part of the lymph fluid from the right/dorsal side of the esophagus drains directly into the thoracic duct, whereas the lymph fluid from the left/ventral side has to pass through lymph nodes before entering the duct. We hypothesized that patients with right/dorsal tumors have a poorer prognosis than those with left/ventral tumors because cancer cells from the right/dorsal quadrant may easily enter the systemic circulation.

Methods

A total of 77 patients with pT1b‐ or pT2‐staged cancers treated by esophagectomy without neoadjuvant treatment were enrolled in this study. Tumor laterality was determined endoscopically.

Results

The tumor location was right/dorsal in 45 patients and left/ventral in 32. The right/dorsal group had a lower lymph node stage (pN, P = 0.043) and shorter disease‐free survival (P = 0.027). Multivariate analysis demonstrated that tumor laterality [hazard ratio (HR): 0.052, 95% confidence interval (CI): 0.007–0.37, P = 0.003], pN (HR: 3.8, 95% CI: 1.7–9.1, P = 0.001), and tumor size (HR: 1.02, 95% CI: 1–1.04, P = 0.02) were independent prognostic factors.

Conclusions

This is the first study to demonstrate a relationship between tumor laterality and prognosis in patients with esophageal squamous cell carcinoma. These findings need to be validated in a prospective large study. J. Surg. Oncol. 2012; 105:66–70. © 2011 Wiley Periodicals, Inc.
AKT1 polymorphisms and survival of early stage non‐small cell lung cancer
Authors: Kim Min Jung , Kang Hyo‐Gyoung , Lee Shin Yup , Jeon Hyo‐Sung , Lee Won‐Kee , Park Ji Young , Lee Eung Bae , Lee Jae Hee , Cha Sung‐Ick , Kim Dong Sun , Kim Chang‐Ho , Kam Sin , Jung Tae Hoon , Park Jae Yong
Published: August 2011

Background and Objectives:

This study was conducted to investigate the impact of polymorphisms in the AKT1 gene on the survival of early stage non‐small cell lung cancer (NSCLC) patients.

Methods:

Three hundred and ten patients with surgically resected NSCLC were enrolled. The rs3803300, rs1130214, rs3730358, rs1130233, and rs2494732 single nucleotide polymorphisms (SNPs) in the AKT1 gene were investigated. The genotype and haplotype associations with overall survival (OS) and disease free survival (DFS) were analyzed.

Results:

The three SNPs (rs3803300, rs1130214, and rs2494732) were significantly associated with survival outcomes on multivariate analysis. When the three SNPs were combined, OS and DFS were decreased in a dose‐dependent manner as the number of bad genotypes increased (Ptrend = <1.0 × 10−4 and 0.001, respectively). Patients with 2 bad genotypes had a significantly worse OS and DFS compared with those with 0 bad genotypes (adjusted hazard ratio (HR) = 3.08, 95% confidence interval (CI) = 1.61–5.89, P = 0.001; and adjusted HR = 2.04, 95% CI = 1.22–3.43, P = 0.01).

Conclusions:

These results suggest that the AKT1 polymorphisms could be used as prognostic markers for the patients with early‐stage NSCLC. J. Surg. Oncol. 2012; 105:167–174. © 2011 Wiley Periodicals, Inc.
Determination of ofloxacin and lomefloxacin in chicken muscle using molecularly imprinted solid‐phase extraction coupled with liquid chromatography
Authors: Qiao Jindong , Yan Hongyuan , Wang Hui , Lv Yunkai
Published: August 2011

A new molecularly imprinted solid‐phase extraction (MISPE) procedure combined with liquid chromatography was developed for the simultaneous selective extraction and determination of ofloxacin (OFL) and lomefloxacin (LOM) in chicken muscle samples. The water‐compatible molecularly imprinted microspheres (MIMs) were synthesized by aqueous suspension polymerization using 2‐hydroxy‐3‐naphthoic acid and 1‐methylpiperazine as mimic templates. The MIMs applied as selective sorbents in SPE method showed high selectivity and affinity to OFL and LOM in complex biological matrices. Good linearity was obtained in a range of 0.025–2.0 μg/g, and the average recoveries of OFL and LOM at three spiked levels ranged from 94.4 to 96.9%, respectively, with the relative standard deviation ≤4.7%. The developed MISPE‐HPLC method was successfully applied to the isolation of OFL and LOM in chicken muscles, which demonstrated the potential ability of the novel MIMs for selective extraction of fluoroquinolones in biological samples.
Determination of bisphenol A with effective pretreatment medium using automated column‐switching HPLC with fluorescence detection
Authors: Tanigawa Tetsuya , Watabe Yoshiyuki , Kubo Takuya , Hosoya Ken
Published: August 2011

A practical way for reducing contaminants, such as humic acids, and solving column‐clogging problem in environmental water analysis with liquid chromatography is proposed. Detection interference by contamination is one of the most important issues of the environmental analyses. Moreover, due to the recent smaller diameter and fine particle size of an analytical column for HPLC system, a column‐clogging problem is another practical difficulty as well. We found it possible to solve these problems by employing column‐switching HPLC, which consists of a pretreatment column containing surface‐modified polymer particles and flow changeover valves for cleaning the remaining matrices in the pretreatment column prior to analysis. This method was successfully applied to actual HPLC‐fluorescence detection of bisphenol A. Limit of detection (LOD) in real sample was <0.7 ng/L. Repeatability was around 1.4% and recovery was around 97% or more. A particular pressure increase was not observed in 150 repeated analyses of real river water samples.
Simultaneous determination nucleosides in marine organisms using ultrasound‐assisted extraction followed by hydrophilic interaction liquid chromatography–electrospray ionization time‐of‐flight mass spectrometry
Authors: Zhao Hengqiang , Chen Junhui , Shi Qian , Li Xin , Zhou Wenhui , Zhang Daolai , Zheng Li , Cao Wei , Wang Xiaoru , Sen‐Chun Lee Frank
Published: August 2011

A new method has been developed based on ultrasound‐assisted extraction (UAE) followed by hydrophilic interaction chromatography (HILIC) and electrospray ionization time‐of‐flight mass spectrometry (ESI‐TOF/MS) for the simultaneous determination of 16 nucleosides and nucleobases in medicinal extracts of various marine organisms. The separation was achieved on a Venusil HILIC column (250×4.6 mm id, 5 μm) and gradient elution using a solution of acetonitrile and buffer (0.20% formic acid and 20 mmol/L ammonium acetate) as the mobile phase. Identification of the 16 target nucleosides and nucleobases was based on the retention time, UV spectra, and mass measurements of the protonated molecules ([M+H]+) and main fragment ions (ESI‐TOF/MS). In addition, non‐target compounds of 2′‐deoxyinosine and four other amino acids were also tentatively identified by ESI‐TOF/MS. The 16 target compounds were quantified by HILIC‐ESI‐TOF/MS under optimized mass conditions. All calibration curves showed good linearity (r2>0.9951). The recoveries were 84.72–124.10%, and the limits of detection of the 16 target compounds were 0.6–130.0 ng/mL. The developed method was applied to quantify the target compounds in 15 batches of various marine organisms. The method has potential applicability for the identification and determination of highly polar and low‐concentration active compounds in marine organisms.
Detection of lard in vegetable oils
Authors: Che Man Yaakob B. , Rohman Abdul
Published: August 2011

The presence of animal fats, in particular lard (pig fat), in any product is of real concern to some communities, especially Muslims and Jews, due to the religious prohibition of these commodities. This is especially so when lard is used as substitute for vegetable oils in foods or other consumer goods such as cosmetics and pharmaceuticals. Manufactures and producers alike should be sensitive towards the issues of unlawful material in these products as halal and kosher markets are expected to proliferate in the coming years. This article highlights some analytical techniques proposed to detect and to quantify lard in vegetable oils such as Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), chromatographic‐based techniques, and electronic nose (EN).
Effect of Candida antarctica Lipase B Immobilization on the Porous Structure of the Carrier
Authors: Miletić Nemanja , Vuković Zorica , Nastasović Aleksandra , Loos Katja
Published: August 2011

A series of poly(GMA‐co‐EGDMA) resins with identical composition but varying particle sizes, pore radii, specific surface areas and specific volumes are studied to assess how Candida antarctica lipase B immobilization affects the porosity of the copolymer particles. Mercury porosimetry reveals a significant change in the average pore size (up to 6.1‐fold), the specific surface area (up to 3.2‐fold) and the specific volume (up to 2.1‐fold) of the epoxy resin. A similar behaviour is observed for glutaraldehyde‐modified epoxy resins. The influences of the resin porosity properties on the loading of Candida antarctica lipase B during immobilization and on the hydrolytic activity (hydrolysis of p‐nitrophenyl acetate) of the immobilized lipase are studied.

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Functional and Highly Porous Scaffolds for Biomedical Applications
Authors: Tyson Therese , Målberg Sofia , Wåtz Veronica , Finne‐Wistrand Anna , Albertsson Ann‐Christine
Published: August 2011

Highly porous functional scaffolds were obtained from linear and cross‐linked multifunctional poly(ε‐caprolactone) and poly(L‐lactide). The polymers were synthesized by ring‐opening polymerization of ε‐caprolactone and L‐lactide using poly(but‐2‐ene‐1,4‐diyl malonate) (PBM) as macroinitiator and stannous 2‐ethylhexanoate. The presence of a double bond in each repeating unit of PBM enabled cross‐linking of both scaffolds and films. Soft and flexible scaffolds were created from cross‐linked PBM. The mechanical properties of scaffolds and films were evaluated under cyclic conditions, with a focus on the compositions and molecular weights. It was obvious that PBM in the polymers and its cross‐linking ability resulted in tunable material characteristics, including an increased ability to recover after repeated loading.

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Water‐Free Synthesis of Polyurethane Foams Using Highly Reactive Diisocyanates Derived from 5‐Hydroxymethylfurfural
Authors: Neumann Christopher N. D. , Bulach Winfried D. , Rehahn Matthias , Klein Roland
Published: August 2011

This paper reports on the synthesis of a new highly reactive diisocyanate monomer based on hydroxymethylfurfural. It further describes its catalyst‐free conversion to linear‐chain thermoplastic polyurethanes as well as to cross‐linked polyurethane foams. In addition, a novel strategy for the synthesis of polyurethane foams without the necessity of using water is developed. Nitrogen is utilized herein as blowing agent which is formed during Curtius rearrangement of a new furan based carboxylic azide into its corresponding diisocyanate.

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Electro‐active Polymer Actuator Based on Sulfonated Polyimide with Highly Conductive Silver Electrodes Via Self‐metallization
Authors: Song Jiangxuan , Jeon Jin‐Han , Oh Il‐Kwon , Park K. C.
Published: August 2011

We report here a facile synthesis of high performance electro‐active polymer actuator based on a sulfonated polyimide with well‐defined silver electrodes via self‐metallization. The proposed method greatly reduces fabrication time and cost, and obviates a cation exchange process required in the fabrication of ionic polymer‐metal composite actuators. Also, the self‐metallized silver electrodes exhibit outstanding metal‐polymer adhesion with high conductivity, resulting in substantially larger tip displacements compared with Nafion‐based actuators.

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High temporal resolution retrospective motion correction with radial parallel imaging
Authors: Lin Wei , Huang Feng , Duensing George R. , Reykowski Arne
Published: August 2011

A method for motion correction in multicoil imaging applications, involving both data collection and reconstruction, is presented. A bit‐reversed radial acquisition scheme, in conjunction with a rapid self‐calibrated parallel imaging method, Generalized auto‐calibrating partial parallel acquisition (GRAPPA) operator for wider radial bands (GROWL), is used to achieve motion correction at a high temporal resolution. View‐by‐view in‐plane motion correction is achieved in 2D imaging, while 3D motion correction is achieved for every two consecutive slice‐encoding planes in 3D imaging. In the proposed technique, GROWL contributes in two aspects: First, a central k‐space circle/cylinder used as the motion‐free reference is generated from a small number of radial lines/planes; Second, undersampled k‐space regions resulting from rotation and inconsistent (e.g. intraview and nonrigid body) motion can be filled in. When compared with navigator‐based motion correction methods, the proposed method does not prolong scan time and can be applied to short‐TR sequences. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Comparison of measuring energy metabolism by different 31P‐magnetic resonance spectroscopy techniques in resting, ischemic, and exercising muscle
Authors: Schmid Albrecht I. , Schrauwen‐Hinderling Vera B. , Andreas Martin , Wolzt Michael , Moser Ewald , Roden Michael
Published: August 2011

Alternate methods to quantify mitochondrial activity or function have been extensively used for studying insulin resistance and type 2 diabetes mellitus, namely saturation transfer and phosphocreatine (PCr) recovery. As these methods are in fact determining different parameters, this study aimed to compare saturation transfer results to PCr recovery measurements within the same group. Fifteen subjects underwent saturation transfer and ischemic exercise‐recovery experiments. PCr decrease during ischemia (Q), induced by cuff inflation, served as an additional measure of resting ATP (adenosine triphosphate) production. ATP synthetic rate (fATP) measured by saturation transfer (0.234 ± 0.043 mM/s) was greater than (Q = 0.0077 ± 0.0011 mM/s), but correlated well with Q (r = 0.63 P = 0.013). Parameters of PCr recovery correlated well with fATP (Qmax,lin: r = 0.71, P = 0.003, Qmax,ADP: r = 0.66, P = 0.007) and Q (Qmax,lin: r = 0.92, P = 0.000002, Qmax,ADP: r = 0.76, P = 0.001). In conclusion, although saturation transfer yields higher ATP synthetic rates than PCr decrease during ischemia, their significant correlation indicates that fATP can be used as a marker of mitochondrial activity. The finding that both Q and fATP correlate with PCr recovery kinetics suggests that skeletal muscle with greater maximal aerobic ATP synthetic rates is also metabolically more active at rest. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Whole body traveling wave magnetic resonance imaging at high field strength: Homogeneity, efficiency, and energy deposition as compared with traditional excitation mechanisms
Authors: Zhang Bei , Sodickson Daniel K. , Lattanzi Riccardo , Duan Qi , Stoeckel Bernd , Wiggins Graham C.
Published: August 2011

In 7 T traveling wave imaging, waveguide modes supported by the scanner radiofrequency shield are used to excite an MR signal in samples or tissue which may be several meters away from the antenna used to drive radiofrequency power into the system. To explore the potential merits of traveling wave excitation for whole‐body imaging at 7 T, we compare numerical simulations of traveling wave and TEM systems, and juxtapose full‐wave electrodynamic simulations using a human body model with in vivo human traveling wave imaging at multiple stations covering the entire body. The simulated and in vivo traveling wave results correspond well, with strong signal at the periphery of the body and weak signal deep in the torso. These numerical results also illustrate the complicated wave behavior that emerges when a body is present. The TEM resonator simulation allowed comparison of traveling wave excitation with standard quadrature excitation, showing that while the traveling wave B per unit drive voltage is much less than that of the TEM system, the square of the average B compared to peak specific absorption rate (SAR) values can be comparable in certain imaging planes. Both systems produce highly inhomogeneous excitation of MR signal in the torso, suggesting that B1 shimming or other parallel transmission methods are necessary for 7 T whole body imaging. Magn Reson Med 67:1183–1193, 2011. © 2011 Wiley‐Liss, Inc.
Spatially encoded phase‐contrast MRI—3D MRI movies of 1D and 2D structures at millisecond resolution
Authors: Merboldt Klaus‐Dietmar , Uecker Martin , Voit Dirk , Frahm Jens
Published: August 2011

This work demonstrates that the principles underlying phase‐contrast MRI may be used to encode spatial rather than flow information along a perpendicular dimension, if this dimension contains an MRI‐visible object at only one spatial location. In particular, the situation applies to 3D mapping of curved 2D structures which requires only two projection images with different spatial phase‐encoding gradients. These phase‐contrast gradients define the field of view and mean spin‐density positions of the object in the perpendicular dimension by respective phase differences. When combined with highly undersampled radial fast low angle shot (FLASH) and image reconstruction by regularized nonlinear inversion, spatial phase‐contrast MRI allows for dynamic 3D mapping of 2D structures in real time. First examples include 3D MRI movies of the acting human hand at a temporal resolution of 50 ms. With an even simpler technique, 3D maps of curved 1D structures may be obtained from only three acquisitions of a frequency‐encoded MRI signal with two perpendicular phase encodings. Here, 3D MRI movies of a rapidly rotating banana were obtained at 5 ms resolution or 200 frames per second. In conclusion, spatial phase‐contrast 3D MRI of 2D or 1D structures is respective two or four orders of magnitude faster than conventional 3D MRI. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Tailored excitation in 3D with spiral nonselective (SPINS) RF pulses
Authors: Malik Shaihan J. , Keihaninejad Shiva , Hammers Alexander , Hajnal Joseph V.
Published: August 2011

Brain images acquired at 3T often display central brightening with spatially varying tissue contrast, caused by inhomogeneity in the transmit radiofrequency fields used for excitation. Tailored radiofrequency pulses can provide mitigation of radiofrequency field inhomogeneity, but previous designs have been unsuitable for 3D imaging in rapid pulse sequences. This article presents a nonselective pulse design based on a short (1 ms) 3D spiral k‐space trajectory that covers low spatial frequencies. The resulting excitations are optimized to produce a uniform excitation within a specified volume of interest covering the whole brain. B1 mapping and pulse calculation times were reduced by optimizing in only five slices within the brain. The method has been tested with both single and parallel transmission: in phantom experiments, normalized root‐mean‐square error in excitation was 0.022 for single and 0.020 for parallel transmission. The corresponding results in vivo were 0.066 and 0.055 respectively. A pilot brain imaging study using the proposed pulses for excitation within the Alzheimer's disease neuroimaging initiative magnetization prepared rapid gradient echo (MP‐RAGE) protocol, yielded excellent image quality with improved signal to noise ratio in peripheral brain regions and enhanced uniformity of contrast compared with standard excitation. Greatest performance enhancement was achieved using parallel transmission, but single channel transmission offers significant improvement over standard excitation pulses. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Spatially dependent filtering for removing phase distortions at the cortical surface
Authors: Ng Amanda , Johnston Leigh , Chen Zhaolin , Cho Zang‐Hee , Zhang Jingxin , Egan Gary
Published: August 2011

Recent advances in high field magnetic resonance technology have increased the interest in the phase of the complex data. Processed phase images are derived from the phase signal by removing the bias field and phase wraps from the initial data. However, the usefulness of this data has been hindered by artifacts at the brain/non‐brain surface, particularly in cortical regions. A method is proposed that efficiently removes surface artifacts by performing Gaussian filtering with spatially varying parameters of unwrapped or complex filtered phase images. The proposed method is shown to produce improved images, revealing underlying structure and detail that are otherwise obscured by surface artifacts in images produced by traditional phase processing methods. Magn Reson Med 66:784–793, 2011. © 2011 Wiley‐Liss, Inc.
Practical and analytical approaches for designing scalable on‐demand policy‐based resource allocation in stateless IP networks
Authors: Haddadou Kamel , Ghamri‐Doudane Samir , Ghamri‐Doudane Yacine , Agoulmine Nazim
Published: August 2011

Today the policy‐based management (PBM) approach is recognized as an efficient solution to simplify the complex task of managing and controlling networks. To this end, the Internet Engineering Task Force (IETF) has introduced a reference framework to build PBM systems. However, this framework only addresses the provisioning of relatively long validity period services based on predefined service‐level agreements. Furthermore, very little work addresses the scalability properties of the instantiation of this framework in a real network. This work aims to extend the IETF PBM framework in order to support dynamic provisioning of short‐term services (end‐system signalling) as well as an instantiation scheme that is scalable (distributed provisioning of edge routers). This instantiation scheme is based on the distribution of the provisioning process while keeping centralized only the parts that involve critical resources, namely bandwidth brokerage. The performance properties of the proposed scheme are then demonstrated throughout both extensive experimentation and an analytical study. The extension of this performance analysis to the case where multiple bandwidth brokers are used is also discussed. The results of this work are intended to be used as a guideline to help network operators to design a scalable PBM system in order to offer to their customers services with quality of service assurance on an on‐demand basis. Copyright © 2011 John Wiley & Sons, Ltd.
Boards and Cords: Discriminating Types of Artificial Cranial Deformation in Prehispanic South Central Andean Populations
Authors: O'Brien T. G. , Stanley A. M.
Published: August 2011

For over a century, a number of ambiguous typologies have been employed to distinctly categorise types of artificial cranial deformation. This paper provides a quantitative method, based on multiple dimensions and discriminant function analysis, by which to assign skulls not only into discrete categories: deformed or not, but also by type: annular or tabular. A series of prehispanic, adult, human crania (n = 469) from archaeological sites in Argentina, Bolivia, Chile and Peru represented by both normal and artificially deformed specimens, provide craniometric data for four measurements across the vault: maximum cranial length, breadth and height and the frontal chord. These data are used to develop three indices which in turn are used to compute two discriminant functions. Results are plotted on a territorial map whereby the type of deformity can be determined. When these methods were applied to a comparative cranial sample of nondeformed skulls from South America, 100% of the samples was found to be nondeformed. When these methods were applied to the samples which were subjectively classified a priori by the first author as nondeformed, 81.3% of the samples were found to be nondeformed. This study demonstrates the value of a more objective and quantitative method by which to classify artificial cranial deformation, and thus provides a new approach. Copyright © 2011 John Wiley & Sons, Ltd.
Chaetophractus villosus: A Disturbing Agent for Archaeological Contexts
Authors: Frontini R. , Escosteguy P.
Published: August 2011

Chaetophractus villosus (Dasypodidae), a medium‐sized armadillo with burrowing habits, is one of the natural agents whose activities play a major role in archaeological deposit disturbance in the Pampean Region in Argentina. This paper presents the results of a comparative analysis between the archaeological materials collected from 32 currently active burrows and the remains collected in the sedimentary matrix identified as burrow filling during excavations of El Guanaco Site 1, Sector 1. As a general tendency, it was possible to establish that C. villosus removes both lithic and faunal materials that are 3 cm long or less. As an exception, materials up to 7 cm long are displaced. The distribution observed during the excavation of currently active burrows indicates that materials concentrate around the burrows' entrances. Copyright © 2011 John Wiley & Sons, Ltd.
Towards global solutions of optimal discrete‐valued control problems
Authors: Woon Siew Fang , Rehbock Volker , Loxton Ryan
Published: August 2011

This paper proposes a new heuristic approach for solving optimal discrete‐valued control problems. We illustrate the approach with an existing hybrid power system model. The problem of choosing an operating schedule to minimize generator, battery, and switching costs is first posed as a mixed discrete dynamic optimization problem. Then, a discrete filled function method is employed in conjunction with a computational optimal control technique to solve this problem. Computational results indicate that this approach is robust, efficient, and can successfully identify a near‐global solution for this complex applied optimization problem despite the presence of multiple local optima. Copyright © 2011 John Wiley & Sons, Ltd.
Polypyrrole/multiwalled carbon nanotubes‐based biosensor for cholesterol estimation
Authors: Singh K. , Solanki Pratima R. , Basu Tinku , Malhotra B. D.
Published: August 2011

The nanocomposite electrode comprising of polypyrrole (PPY) and carboxy functionalized multiwalled carbon nanotubes (MWCNT) has been electrochemically fabricated onto indium–tin–oxide (ITO) electrode using p‐toluene sulfonic acid (PTS). Cholesterol oxidase (ChOx) and cholesterol esterase (ChEt) have been immobilized onto this PPY– MWCNT/ITO nanocomposite electrode using N‐ethyl‐N‐(3‐dimethylaminopropyl) carbodiimide and N‐hydroxy succinimide chemistry for estimation of esterified cholesterol. The ChEt–ChOx/PPY–MWCNT/PTS/ITO bioelectrode has been characterized using Fourier transform infrared spectroscopy, electrochemical techniques, and scanning electron microscope. This ChEt–ChOx/PPY–MWCNT/PTS/ITO nanobioelectrode has a response time of about 9 s, linearity of 4 × 10−4 to 6.5 × 10−3 M/l of cholesterol oleate concentration, Km of 0.02 mM, and thermal stability of upto 45°C. This electrode exhibits improved biosensing characteristics compared with other total cholesterol electrodes reported in literature till date and can be used to estimate cholesterol in blood serum samples. Copyright © 2011 John Wiley & Sons, Ltd.