bluuebunny/crossref_metadata_2025 huggingface dataset:
Doxycycline treatment prevents alveolar destruction in VEGF‐deficient mouse lung
Authors: Rossiter Harry B. , Scadeng Miriam , Tang Kechun , Wagner Peter D. , Breen Ellen C.
Published: January 2008

In vivo lung‐targeted VEGF gene inactivation results in pulmonary cell apoptosis, airspace enlargement, and increased lung compliance consistent with an emphysema‐like phenotype. The predominant hypothesis for the cause of lung destruction in emphysema is an imbalance between active lung protease and anti‐protease molecules. Therefore, we investigated the role of protease (e.g., matrix metalloproteinases—MMPs) and anti‐protease (e.g., tissue inhibitors of metalloproteinases—TIMPs) expression in contributing to the lung structural remodeling observed in pulmonary‐VEGF‐deficient mice. VEGFLoxP mice instilled through the trachea with an adeno‐associated virus expressing Cre recombinase (AAV/Cre) manifest airspace enlargement and a greater (P < 0.05) mean linear intercept (MLI: 44.2 ± 4.2 µm) compared to mice instilled with a control virus expressing LacZ (31.3 ± 2.5 µm). Airspace enlargement was prevented by the continuous administration of the general MMP inhibitor, doxycycline (Dox) (Cre + Dox: 32.6 ± 2.5 µm), and MLI values were not different from either control (LacZ + Dox: 30.5 ± 1.2 µm). In situ magnetic resonance imaging of VEGF gene inactivated mouse lungs revealed uneven inflation, residual trapped gas volumes upon oxygen absorption deflation/re‐inflation, and loss of parenchymal structure; effects that were largely prevented by Dox. Five weeks after AAV/Cre infection Western blot revealed a 9.9‐fold increase in pulmonary MMP‐3, and 2‐fold increases in MMP‐9 and TIMP‐2. However, the increase in MMP‐3 was prevented by Dox administration and was associated with a 2‐fold increase in serpin b5 (Maspin) expression. These results suggest that doxycycline treatment largely prevents the aberrant lung remodeling response observed in VEGF‐deficient mouse lungs and is associated with changes in protease and anti‐protease expression. J. Cell. Biochem. 104: 525–535, 2008. © 2008 Wiley‐Liss, Inc.
Synthesis of 14C‐labeled and 13C‐,15N‐labeled dasatinib and its piperazine N‐dealkyl metabolite
Authors: Allentoff Alban J. , Lago Michael W. , Ogan Marc , Chen Bang‐Chi , Zhao Rulin , Iyer Ramaswarmy A. , Christopher Lisa J. , Rinehart J. Kent , Balasubramanian Balu , Bonacorsi Samuel J.
Published: January 2008

Dasatinib (SPRYCEL®) is a multiple kinase inhibitor approved for the treatment of chronic myelogenous leukemia and Philadelphia chromosome‐positive acute lymphoblastic leukemia in patients with resistance to prior therapy, including imatinib mesylate (Gleevec®). Radiolabeled dasatinib and its piperazine N‐dealkyl metabolite were synthesized to investigate absorption, distribution, metabolism, and elimination of the compounds in humans and animals. These compounds were prepared following a three‐step sequence, which included thiazole carboxamide formation via cyclization of labeled thiourea with a brominated oxyacrylamide precursor. In the final step a common intermediate was converted to either [14C]dasatinib or the radiolabeled piperazine N‐dealkyl metabolite with labeling in the aminothiazole ring. Syntheses of both compounds were achieved with radiochemical purities in excess of 98%. Stable‐labeled dasatinib and the piperazine N‐dealkyl metabolite were also needed for use as mass spectral internal standards in support of bioanalytical assays. By following the same route used for the carbon‐14 synthesis, [13C4, 15N2]dasatinib and the [13C4, 15N2]metabolite were prepared with labeling in both the dichloropyrimidine and thiazole ring systems. This convergent process introduced stable isotope labeling through (1, 2, 3‐13C3) diethyl malonate and [13C,15N2]thiourea. Copyright © 2008 John Wiley & Sons, Ltd.
Hepatocellular carcinoma treated with radio frequency ablation: An early evaluation with magnetic resonance imaging
Authors: Khankan Azzam A. , Murakami Takamichi , Onishi Hiromitsu , Matsushita Masaki , Iannaccone Riccardo , Aoki Yoshiko , Tono Takeshi , Kim Tonsok , Hori Masatoshi , Osuga Keigo , Passariello Roberto , Nakamura Hironobu
Published: January 2008

Purpose

To determine the usefulness of nonenhanced T1‐weighted spoiled gradient‐recalled acquisition in the steady‐state (SPGR) MRI in the early assessment of the efficacy of radio frequency (RF) therapy for hepatocellular carcinoma (HCC).

Materials and Methods

A total of 23 patients with 28 HCC nodules treated with percutaneous RF ablation underwent nonenhanced MRI within two days after the RF procedure and contrast‐enhanced computed tomography (CT) one week after. MR assessment of ablation efficacy according to the concentric zonal pattern on T1‐weighted SPGR imaging was compared with the one‐week CT and presence of local recurrence by means of follow‐up study for 12 months or more.

Results

In 18 of 28 ablated nodules, SPGR images revealed a central hyperintense zone covering the entire tumor, CT showed a nonenhanced area covering the entire tumor, and no local recurrence was demonstrated in the follow‐up studies. In nine of 28 nodules, the central hyperintense zone did not cover the entire tumor; and local recurrence was demonstrated in three nodules. In the remaining one nodule, no signal change was seen in the treated area on SPGR images and CT showed the presence of residual viable tumor.

Conclusion

Nonenhanced T1‐weighted MRI was considered useful for early assessment of the efficacy of RF therapy for HCC. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
A modified fourier‐based phase unwrapping algorithm with an application to MRI venography
Authors: Bagher‐Ebadian Hassan , Jiang Quan , Ewing James R.
Published: January 2008

Purpose

To present a single‐step deterministic procedure for unwrapping MRI phase maps.

Materials and Methods

Using an algorithm previously developed for optical applications, Laplacian operators were applied in the Fourier space of the MRI phase map. The original Fourier‐based phase unwrapping algorithm was modified so that demodulation accomplished the required signal symmetrization in Fourier space. To evaluate the method's performance in the presence of thermal noise, a set of wrapped phase maps were simulated at different levels of noise in k‐space, and the response of the algorithm at different levels of signal‐to‐noise ratio (SNR) was evaluated for stability. To demonstrate its utility in MRI, the algorithm was applied to the wrapped phase maps of susceptibility‐weighted imaging (SWI) studies, which were then used to generate venograms.

Results

In simulated phase wrapping, the algorithm correctly reproduced the original phase for a wide range of phase gradients and noise. The procedure was fast and produced useful maps of venous structures in SWI images.

Conclusion

A fast and stable single‐step deterministic method for unwrapping MRI phase maps is available for such applications as SWI and mapping of static magnetic field inhomogeneity. J. Magn. Reson. Imaging 2008. © 2008 Wiley‐Liss, Inc.
First‐pass myocardial perfusion image registration by maximization of normalized mutual information
Authors: Wong Kelvin K. , Yang Edward S. , Wu Ed X. , Tse Hung‐Fat , Wong Stephen T.
Published: January 2008

Purpose

To evaluate a left ventricular image registration algorithm for first‐pass MR myocardial perfusion.

Materials and Methods

A normalized mutual information based motion correction algorithm was proposed and tested on 27 adenosine stressed myocardial perfusion cases consisting of pretreatment and posttreatment of 15 patients undergone autologous bone marrow mononuclear cell transplant therapy. An image mask approximately covering the left and right ventricles was manually defined to include a region of interest for registration. A two‐dimensional multiresolution registration approach was used to register consecutively acquired multislice images with in‐plane translations. The method was validated by manual registration and singular value deconvolution based perfusion analysis.

Results

The proposed image registration algorithm was found to be robust in minimizing the in‐plane motion of the left ventricle in first‐pass myocardial perfusion. The image mask including the left and right ventricle was found to be more robust than including the left ventricle alone. A smooth estimate of normalized mutual information coefficients were achieved for images with large contrast changes.

Conclusion

The proposed semiautomatic multiresolution registration algorithm was able to register first‐pass MR myocardial perfusion images and may be useful in quantitative perfusion analysis. J. Magn. Reson. Imaging 2008. © 2008 Wiley‐Liss, Inc.
YFa, a chimeric opioid peptide, induces kappa‐specific antinociception with no tolerance development during 6 days of chronic treatment
Authors: Vats Ishwar Dutt , Dolt Karamjit Singh , Kumar Krishan , Karar Jayashree , Nath Mahendra , Mohan Anita , Pasha M. A. Qadar , Pasha Santosh
Published: January 2008

Our previous study showed that YGGFMKKKFMRFamide (YFa), a chimeric peptide of Met‐enkephalin, and Phe‐Met‐Arg‐Phe‐NH2induced naloxone‐reversible antinociception and attenuated the development of tolerance to morphine analgesia. In continuation, the present study investigated which specific opioid receptors—μ, δ or κ—mediate the observed YFa antinociception pharmacologically using specific antagonists and whether chronic administration of YFa at 26.01 μmol/kg per day induces tolerance and its effect on the expression of μ and κ opioid receptors from day 4 to day 6, with endomorphine‐1 (EM‐1) and saline taken as positive and negative controls, respectively. Quantitative differential expression analysis was carried out by real‐time reverse‐transcriptase polymerase chain reaction, and the corresponding changes in protein levels were assessed by Western blot. A pharmacological investigation revealed that nor‐binaltorphimine, a specific κ opioid receptor–1 (KOR1) antagonist, completely antagonized the antinociception induced by 39.01 μmol/kg of YFa. Importantly, its chronic intraperitoneal administration did not result in significant tolerance over 6 days, whereas EM‐1 induced significant tolerance after day 4. Differential expression analysis revealed that EM‐1 caused up‐regulation of μ opioid receptor–1 on day 4, followed by down‐regulation on later days. Interestingly, YFa treatment caused a decrease on day 4, followed by an increase in the expression of KOR1 from day 5 onward. In conclusion, YFa induces kappa‐specific antinociception, with no development of tolerance during 6 days of chronic treatment, which further articulates new directions for improved designing of peptide‐based analgesics that may be devoid of adverse effects like tolerance. © 2008 Wiley‐Liss, Inc.
In vivo acute treatment with trimethyltin chloride causes neuronal degeneration in the murine olfactory bulb and anterior olfactory nucleus by different cascades in each region
Authors: Kawada Koichi , Yoneyama Masanori , Nagashima Reiko , Ogita Kiyokazu
Published: January 2008

Our earlier study demonstrated that in vivo acute treatment with trimethyltin chloride (TMT) produces severe neuronal damage in the dentate gyrus and cognition impairment in mice. In the present study, we assessed whether TMT was capable of causing neuronal degeneration in the olfactory bulb (OB) and anterior olfactory nucleus (AON) of the mouse brain. An intraperitoneal injection of TMT at the dose of 2.8 mg/kg led to a dramatic increase in the number of degenerating cells, which were reactive with antibody against single‐stranded DNA, in the granule cell layer (GCL) of the OB and AON 1 day and 2 days later, respectively. TMT treatment produced a marked translocation of phospho‐c‐Jun‐N‐terminal kinase from the cytoplasm to the nucleus in the AON. Expectedly, a marked increase in phospho‐c‐Jun‐positive cells was seen in the AON after the treatment. In addition to the AON, the mitral cell layer of the olfactory bulb showed the presence of phospho‐c‐Jun‐positive cells after the treatment. However, the GCL had no cells positive for either phospho‐c‐Jun‐N‐terminal kinase or phospho‐c‐Jun at any time after the treatment with TMT. Similarly, TMT‐induced nuclear translocation of the lysosomal enzyme deoxyribonuclease II was seen in the AON, but not in the GCL. On the other hand, TMT elicited the expression of activated caspase 3 in the GCL but not in the AON. Taken together, our results suggest that TMT is capable of causing neuronal degeneration in the murine OB and AON through different cascades in the two structures. © 2008 Wiley‐Liss, Inc.
Studies of polyamines transport through liquid membranes with D2EHPA as a carrier
Authors: Dziarkowska Katarzyna , Koprek Katarzyna , Wieczorek Piotr P.
Published: January 2008

The transport of polyamines through the liquid membranes with di‐2‐ethylhexyl phosphoric acid (D2EHPA) was investigated. The study was performed in three main steps: liquid–liquid extraction (LLE), bulk liquid membrane (BLM) extraction, and supported liquid membrane (SLM) extraction. Equilibrium distribution experiments allowed determining the extraction constants and stoichiometric coefficients for each polyamine. It turned out that one amino group binds two molecules of carrier (one D2EHPA dimer) and the extractability of polyamine rises with the increase in number of function groups in the molecule. The BLM and SLM experiments showed that despite considerable differences in distribution ratio between various polyamines the extraction efficiencies for all of them are very approximate. The smaller diamines compensate the lowest affinity to membrane phase with faster interface reaction kinetics and higher diffusivity. Finally, the SLM extraction conditions were optimized. The main parameters that influence the transport are the pH of the donor and acceptor phases. The extraction efficiencies obtained for polyamines are high (80–90%) and give hope for an application in bioanalytical chemistry.
Comparison of high performance TLC and HPLC for separation and quantification of chlorogenic acid in green coffee bean extracts
Authors: Urakova Irina N. , Pozharitskaya Olga N. , Shikov Alexander N. , Kosman Vera M. , Makarov Valery G.
Published: January 2008

Two chromatographic methods, high‐performance TLC (HPTLC) and HPLC, were developed and used for separation and quantitative determination of chlorogenic acid in green coffee bean extracts. For HPTLC silica gel Kieselgel 60 F 254 plates with ethyl acetate/dichlormethane/formic acid/acetic acid/water (100:25:10:10:11, v/v/v/v/v) as mobile phase were used. Densitometric determination of chlorogenic acid by HPTLC was performed at 330 nm. A gradient RP HPLC method was carried out at 330 nm. All necessary validation tests for both methods were developed for their comparison. There were no statistically significant differences between HPLC and HPTLC for quantitative determination of chlorogenic acid according to the test of equality of the means.
Different choices of scaling in homogenization of diffusion and interfacial exchange in a porous medium
Authors: Peter Malte A. , Böhm Michael
Published: January 2008

Several choices of scaling are investigated for a coupled system of parabolic partial differential equations in a two‐phase medium at the microscopic scale. This system may be regarded as modelling a reaction–diffusion problem, the Stokes problem of single‐phase flow of a slightly compressible fluid or as a heat conduction problem (with or without interfacial resistance), for example. It is shown that, starting with the same problem on the microscopic scale, different choices of scaling of the diffusion coefficients (resp. permeability or conductivity) and the interfacial‐exchange coefficient lead to different types of macroscopic systems of equations. The characterization of the limit problems in terms of the scaling parameters constitutes a modelling tool because it allows to determine the right type of limit problem. New macroscopic models, not previously dealt with, arise and, for some scalings, classical macroscopic models are recovered. Using the method of two‐scale convergence, a unified approach yielding rigorous proofs is given covering a very broad class of different scalings. Copyright © 2008 John Wiley & Sons, Ltd.
The Influence of Xanthate‐Based Transfer Agents on Styrene Emulsion Polymerization: Mathematical Modeling and Model Validation
Authors: Altarawneh Ibrahem S. , Gomes Vincent G. , Srour Mourtada S.
Published: January 2008

A mathematical model was developed to account for the evolution of polymer product attributes in the emulsion polymerization of styrene. The effects of transfer agent, surfactant, initiator and temperature were investigated. Polymerization rate, $\overline M _{\rm n}$ and particle size decreased with increasing concentration of the transfer agent. The polymerization rate increased with increasing surfactant and initiator concentrations, while an increase in temperature led to a decrease of molecular weight but an increase of polymerization rate and particle size. Chain extension was successfully achieved in the presence of our RAFT agent. The model predictions compared well with our experimental results.

magnified image
3D magnetization prepared elliptical centric fast gradient echo imaging
Authors: Lin Chen , Bernstein Matt A.
Published: January 2008

3D magnetization‐prepared fast gradient echo MR sequences, such as MP‐RAGE and IR‐SPGR, provide good spatial resolution and gray‐white contrast. The efficiency and image quality of these techniques can be further improved with an interleaved, recessed elliptical centric view order. It is shown that this novel acquisition strategy, along with skipping the acquisition of views ink‐space corners can provide images with higher signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR), while reducing artifact level and scan time compared to standard MP‐RAGE. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.
Considerations in determining sample size for pilot studies
Authors: Hertzog Melody A.
Published: January 2008

There is little published guidance concerning how large a pilot study should be. General guidelines, for example using 10% of the sample required for a full study, may be inadequate for aims such as assessment of the adequacy of instrumentation or providing statistical estimates for a larger study. This article illustrates how confidence intervals constructed around a desired or anticipated value can help determine the sample size needed. Samples ranging in size from 10 to 40 per group are evaluated for their adequacy in providing estimates precise enough to meet a variety of possible aims. General sample size guidelines by type of aim are offered. © 2008 Wiley Periodicals, Inc. Res Nurs Health 31:180–191, 2008
Translocation or membrane disintegration? Implication of peptide–membrane interactions in pep‐1 activity
Authors: Henriques Sónia Troeira , Castanho Miguel A. R. B.
Published: January 2008

The Cell membrane is impermeable for most peptides, proteins, and oligonucleotides. Moreover, some cationic peptides, the so‐called cell‐penetrating peptides (CPPs), are able to translocate across the membrane. This observation has attracted much attention because these peptides can be covalently coupled to different macromolecules, which are efficiently delivered inside the cell. The mechanism used by these peptides to pass across the membrane is a controversial matter of debate. It has been suggested that endocytosis is the main mechanism of internalization and this was confirmed by several studies for different peptides. Pep‐1 is an exception worthy of attention for its ability to translocate cargo macromolecules without the need to be covalently attached to them. A preferential internalization by an endocytosis‐independent mechanism was demonstrated both in vitro and in vivo. Pep‐1 has a high affinity to lipidic membranes, it is able to insert and induce local destabilization in the lipidic bilayer, although without pore formation. No cytotoxic effects were found for pep‐1 concentrations where translocation is fully operative. At much higher concentrations, membrane disintegration takes place by a detergent‐like mechanism that resembles anti‐microbial peptide activity. In this review, the ability of pep‐1 to transverse the membrane by an endocytosis‐independent mechanism, not mediated by pores as well as an ability to induce membrane disintegration at high peptide concentration, is demonstrated. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Quantitative microstructure characterization of self‐annealed copper films with electron backscatter diffraction
Authors: Pantleon Karen , Gholinia Ali , Somers Marcel A. J.
Published: January 2008

Electron backscatter diffraction (EBSD) was applied to analyze cross sections of self‐annealed copper electrodeposits, for which earlier the kinetics of self‐annealing had been investigated byin‐situX‐ray diffraction (XRD). The EBSD investigations on the grain size, grain boundary character and crystallographic texture of copper films with different thicknesses essentially supplement results fromin‐situXRD. Twin relations between neighboring grains were identified from the orientation maps and the observed twin chains confirm multiple twinning in copper electrodeposits as the mechanism of microstructure evolution at room temperature (self‐annealing). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Raman mode shifts correlated with conductivity and Young's modulus changes in modified carbon nanotube networks
Authors: Skákalová V. , Kaiser A. B. , Roth S.
Published: January 2008

We have discovered a remarkable correlation between frequency shifts in G+, D and D* Raman modes and changes in the conductivity and Young's modulus of freestanding single‐wall carbon nanotube (SWNT) networks. On ion irradiation, all these properties show similar peaks as a function of irradiation dose. On acceptor doping that increases conductivity, increases are also observed in the Raman mode frequencies that are analogous to the irradiation effects. We discuss possible mechanisms for these correlated changes in properties. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron transfer dissociation in the hexapole collision cell of a hybrid quadrupole‐hexapole Fourier transform ion cyclotron resonance mass spectrometer
Authors: Kaplan Desmond A. , Hartmer Ralf , Speir J. Paul , Stoermer Carsten , Gumerov Dmitry , Easterling Michael L. , Brekenfeld Andreas , Kim Taeman , Laukien Frank , Park Melvin A.
Published: January 2008

Electron transfer dissociation (ETD) of proteins is demonstrated in a hybrid quadrupole‐hexapole Fourier transform ion cyclotron resonance mass spectrometer (Qh‐FTICRMS). Analyte ions are selected in the mass analyzing quadrupole, accumulated in the hexapole linear ion trap, reacted with fluoranthene reagent anions, and then analyzed via an FTICR mass analyzer. The hexapole trap allows for a broad fragment ion mass range and a high ion storage capacity. Using a 3 T FTICRMS, resolutions of 60 000 were achieved with mass accuracies averaging below 1.4 ppm. The high resolution, high mass accuracy ETD spectra provided by FTICR obviates the need for proton transfer reaction (PTR) charge state reduction of ETD product ions when analyzing proteins or large peptides. This is demonstrated with the ETD of ubiquitin and apomyoglobin yielding sequence coverages of 37 and 20%, respectively. We believe this represents the first reported successful combination of ETD and a FTICRMS. Copyright © 2008 John Wiley & Sons, Ltd.
Insulins in equine urine: qualitative analysis by immunoaffinity purification and liquid chromatography/tandem mass spectrometry for doping control purposes in horse‐racing
Authors: Kuuranne Tiia , Thomas Andreas , Leinonen Antti , Delahaut Philippe , Bosseloir Alan , Schänzer Wilhelm , Thevis Mario
Published: January 2008

Insulin is a peptide hormone consisting of two peptide chains (A‐ and B‐chain) that are cross‐linked by two disulfide bonds. To obtain improved pharmacokinetic onset of action profiles of insulin treatment in diabetic patients, recombinant long‐, intermediate‐, and rapid‐acting insulin analogs are produced, in which the C‐terminal end of the B‐chain plays an especially important role.

A review of the veterinary literature reveals the low prevalence of equine type I diabetes mellitus, which indicates that the therapeutic use of insulin in racing horses is unlikely. Although there is no unequivocal evidence of an overall performance‐enhancing effect of insulin, in human sports the misuse of insulin preparations is reported among elite athletes. The desired effects of insulin include the increase of muscular glycogen prior to sports event or during the recovery phase, in addition to a chalonic action, which increases the muscle size by inhibiting protein breakdown.

In the present study urinary insulin was detected in equine samples and differences between equine insulin, human insulin, as well as rapidly acting recombinant insulin variants were examined. The method was based on sample purification by solid‐phase extraction (SPE) and immunoaffinity chromatography (IAC), and subsequent analysis by microbore liquid chromatography (LC) and tandem mass spectrometry (MS/MS) using top‐down sequencing for the determination of various insulins. Product ion scan experiments of intact proteins and B‐chains enabled the differentiation between endogenously produced equine insulin, its DesB30 metabolite, human insulin and recombinant insulin analogs, and the assay allowed the assignment of individual product ions, especially those originating from modified C‐termini of B‐chains. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis of Cleavable Aryl Sulfonate Anionic Surfactants and a Study of their Surface Activity
Authors: Chen Lin , Hu Zhiyong , Zhu Hailin , Xue Zhuanru
Published: January 2008

A series of cleavable aryl sulfonate anionic surfactants were synthesized from cyanuric chloride, aliphatic amine and H‐acid mono sodium salt. Their structures were identified by 1H NMR, Infrared Spectrum (IR) and Elementary Analysis (EA). Their critical micelle concentrations (CMC) in aqueous solutions at 25 °C were determined by a steady‐state fluorescence probe method and a surface‐tension method. With the increasing length of the carbon chain, the value of their CMCs and surface tensions under CMC (γCMC) initially decreased and then reached a minimum (respectively 2.63 × 10−5 mol L−1 and 28.29 mN m−1) when the carbon number was 10. The CMC and γCMC then increased when the carbon number was increased to 12. The results showed that, compared with sodium dodecyl benzene sulfonate (SDBS), such kinds of surfactants have much lower surface adsorption amounts and greater molecular areas on the aqueous surface.
Evaluating the Evidence: Web Sites
Authors: Hoss Brenda , Hanson Diane
Published: January 2008

EVIDENCE‐BASED PRACTICE (EBP) is essential to improving patient safety and the effectiveness of health care practices, but a lack of computer literacy can hinder access to and availability of EBP in the clinical setting.

ACCURATE EVALUATION of web site content is essential, including determining bias, validity, and fit to a patient population.

METHODS TO EVALUATE WEB SITES and techniques for efficient access to web resources are presented and discussed. AORN J 87 (January 2008) 124‐141. © AORN, Inc, 2008.
Antihypertensive effect of biotin in stroke-prone spontaneously hypertensive rats
Authors: Watanabe-Kamiyama Mari , Kamiyama Shin , Horiuchi Kimiko , Ohinata Kousaku , Shirakawa Hitoshi , Furukawa Yuji , Komai Michio
Published: January 2008

Biotin is a member of the vitamin B-complex family. Biotin deficiency has been associated with hyperglycaemia and insulin resistance in animals and humans. In the present study, we investigated the pharmacological effects of biotin on hypertension in the stroke-prone spontaneously hypertensive rat (SHRSP) strain. We observed that long-term administration of biotin decreased systolic blood pressure in the SHRSP strain; also, a single dose of biotin immediately decreased systolic blood pressure in this strain. Pretreatment with the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazole [4,3-α]quinoxalin-1-one abolished the hypotensive action of biotin in the SHRSP strain, while pretreatment with the NO synthase inhibitorNG-nitro-l-arginine methyl ester had no effect on the action of biotin. Biotin reduced coronary arterial thickening and the incidence of stroke in the SHRSP strain. These results suggest that the pharmacological dose of biotin decreased the blood pressure of the SHRSPviaan NO-independent direct activation of soluble guanylate cyclase. Our findings reveal the beneficial effects of biotin on hypertension and the incidence of stroke.
SOME $\mathbb{Z}_{n-1}$ TERRACES FROM $\mathbb{Z}_{n}$ POWER-SEQUENCES, $n$ BEING AN ODD PRIME POWER
Authors: Anderson Ian , Preece D. A.
Published: January 2008

A terrace for $\mathbb{Z}_m$ is a particular type of sequence formed from the $m$ elements of $\mathbb{Z}_m$. For $m$ odd, many procedures are available for constructing power-sequence terraces for $\mathbb{Z}_m$; each terrace of this sort may be partitioned into segments, of which one contains merely the zero element of $\mathbb{Z}_m$, whereas every other segment is either a sequence of successive powers of an element of $\mathbb{Z}_m$ or such a sequence multiplied throughout by a constant. We now refine this idea to show that, for $m=n-1$, where $n$ is an odd prime power, there are many ways in which power-sequences in $\mathbb{Z}_n$ can be used to arrange the elements of $\mathbb{Z}_n\setminus\{0\}$ in a sequence of distinct entries $i$, $1\le i\le m$, usually in two or more segments, which becomes a terrace for $\mathbb{Z}_m$ when interpreted modulo $m$ instead of modulo $n$. Our constructions provide terraces for $\mathbb{Z}_{n-1}$ for all prime powers $n$ satisfying $0\ltn\lt300$ except for $n=125$, $127$ and $257$.
ALGEBRA HOMOMORPHISMS FROM REAL WEIGHTED $L^1$ ALGEBRAS
Authors: Miana Pedro J.
Published: January 2008

We characterize algebra homomorphisms from the Lebesgue algebra $L^1_\omega(\mathbb{R})$ into a Banach algebra $\mathcal{A}$. As a consequence of this result, every bounded algebra homomorphism $\varPhi:L^1_\omega(\mathbb{R})\to\mathcal{A}$ is approached through a uniformly bounded family of fractional homomorphisms, and the Hille–Yosida theorem for $C_0$-groups is proved.
ON OPERATORS CAUCHY DUAL TO 2-HYPEREXPANSIVE OPERATORS
Authors: Chavan Sameer
Published: January 2008

The operator Cauchy dual to a $2$-hyperexpansive operator $T$, given by $T'\equiv T(T^*T)^{-1}$, turns out to be a hyponormal contraction. This simple observation leads to a structure theorem for the $C^*$-algebra generated by a $2$-hyperexpansion, and a version of the Berger–Shaw theorem for $2$-hyperexpansions.

As an application of the hyperexpansivity version of the Berger–Shaw theorem, we show that every analytic $2$-hyperexpansive operator with finite-dimensional cokernel is unitarily equivalent to a compact perturbation of a unilateral shift.
MULTIPLE SOLUTIONS FOR A QUASILINEAR ELLIPTIC VARIATIONAL SYSTEM ON STRIP-LIKE DOMAINS
Authors: Cammaroto F. , Chinní A. , Di Bella B.
Published: January 2008

We consider the quasilinear elliptic variational system

\begin{alignat*} {2} -\Delta_pu\amp=\lambda F_u(x,u,v)+\mu H_u(x,u,v) \quad\amp \amp\text{in }\varOmega, \\ -\Delta_qv\amp=\lambda F_v(x,u,v)+\mu H_v(x,u,v) \amp \amp \text{in }\varOmega, \\ u\amp=v=0 \amp \amp \text{on }\partial\varOmega, \end{alignat*}

where $\varOmega$ is a strip-like domain and $\lambda$ and $\mu$ are positive parameters. Using a recent two-local-minima theorem and the principle of symmetric criticality, existence and multiplicity are proved under suitable conditions on $F$.
INTERPOLATION METHODS DEFINED BY MEANS OF POLYGONS AND COMPACT OPERATORS
Authors: Fernández-Cabrera Luz M. , Martínez Antón
Published: January 2008

We work with interpolation methods for $N$-tuples of Banach spaces associated with polygons. We compare necessary conditions for interpolating closed operator ideals with conditions required to interpolate compactness. We also establish a formula for the measure of non-compactness of interpolated operators.
Loss of nitrogen and carbon during storage of the fibrous fraction of separated pig slurry and influence on nitrogen availability
Authors: PETERSEN J. , SØRENSEN P.
Published: January 2008

Manure production in the most livestock-intensive areas exceeds the crop demand for nutrients and legislative restrictions on application rate cause a shortage of land for manure application. Export of nutrients in the fibrous fraction of separated animal slurry has become an option for sustaining or increasing livestock production in livestock-intensive areas. The nitrogen (N) and carbon (C) losses during on-farm storage of the fibrous fraction, originating from separation of anaerobically digested pig slurry using the non-volatile elements phosphorus (P), copper (Cu) and zinc (Zn) as internal references, were calculated. In addition, the plant availability of N in fresh and stored fibrous fractions was evaluated in an incubation experiment. The losses of N and C were greater from the heap surface than from the centre, and turning the heap by reloading for transport increased the losses. The proportion of ammonium N, total N and C lost during storage of the fibrous fraction was 0·30–0·90, 0·10–0·55 and 0·35–0·70 of the initial amount, respectively. Storage reduced the plant-available N and the amount of residual organic N, thereby having long-term influence on soil fertility. The plant-available N in fresh fibrous fractions was 0·22–0·52 of total N, but decreased to 0·15–0·38 after storage due to a decrease of the Nammonium:Ntotal ratio during storage. The net mineralization of manure N was negatively related to the Ctotal:Norganic ratio. The fibrous fraction of separated pig slurry may be characterized as a manure with a high potential for loss and a variable value as fertilizer.
Stability of detonations for an idealized condensed-phase model
Authors: SHORT M. , ANGUELOVA I. I. , ASLAM T. D. , BDZIL J. B. , HENRICK A. K. , SHARPE G. J.
Published: January 2008

The stability of travelling wave Chapman–Jouguet and moderately overdriven detonations of Zeldovich–von Neumann–Döring type is formulated for a general system that incorporates the idealized gas and condensed-phase (liquid or solid) detonation models. The general model consists of a two-component mixture with a one-step irreversible reaction between reactant and product. The reaction rate has both temperature and pressure sensitivities and has a variable reaction order. The idealized condensed-phase model assumes a pressure-sensitive reaction rate, a constant-γ caloric equation of state for an ideal fluid, with the isentropic derivative γ=3, and invokes the strong shock limit. A linear stability analysis of the steady, planar, ZND detonation wave for the general model is conducted using a normal-mode approach. An asymptotic analysis of the eigenmode structure at the end of the reaction zone is conducted, and spatial boundedness (closure) conditions formally derived, whose precise form depends on the magnitude of the detonation overdrive and reaction order. A scaling analysis of the transonic flow region for Chapman–Jouguet detonations is also studied to illustrate the validity of the linearization for Chapman–Jouguet detonations. Neutral stability boundaries are calculated for the idealized condensed-phase model for one- and two-dimensional perturbations. Comparisons of the growth rates and frequencies predicted by the normal-mode analysis for an unstable detonation are made with a numerical solution of the reactive Euler equations. The numerical calculations are conducted using a new, high-order algorithm that employs a shock-fitting strategy, an approach that has significant advantages over standard shock-capturing methods for calculating unstable detonations. For the idealized condensed-phase model, nonlinear numerical solutions are also obtained to study the long-time behaviour of one- and two-dimensional unstable Chapman–Jouguet ZND waves.
Entrainment and motion of coarse particles in a shallow water stream down a steep slope
Authors: ANCEY C. , DAVISON A. C. , BÖHM T. , JODEAU M. , FREY P.
Published: January 2008

We investigate the entrainment, deposition and motion of coarse spherical particles within a turbulent shallow water stream down a steep slope. This is an idealization of bed-load transport in mountain streams. Earlier investigations have described this kind of sediment transport using empirical correlations or concepts borrowed from continuum mechanics. The intermittent character of particle transport at low-water discharges led us to consider it as a random process. Sediment transport in this regime results from the imbalance between entrainment and deposition of particles rather than from momentum balance between water and particles. We develop a birth–death immigration–emigration Markov process to describe the particle exchanges between the bed and the water stream. A key feature of the model is its long autocorrelation times and wide, frequent fluctuations in the solid discharge, a phenomenon never previously explained despite its ubiquity in both nature and laboratory experiments. We present experimental data obtained using a nearly two-dimensional channel and glass beads as a substitute for sediment. Entrainment, trajectories, and deposition were monitored using a high-speed digital camera. The empirical probability distributions of the solid discharge and deposition frequency were properly described by the theoretical model. Experiments confirmed the existence of wide and frequent fluctuations of the solid discharge, and revealed the existence of long autocorrelation time, but theory overestimates the autocorrelation times by a factor of around three. Particle velocity was weakly dependent on the fluid velocity contrary to the predictions of the theoretical model, which performs well when a single particle is moving. For our experiments, the dependence of the solid discharge on the fluid velocity is entirely controlled by the number of moving particles rather than by their velocity. We also noted significant changes in the behaviour of particle transport when the bed slope or the water discharge was increased. The more vigorous the stream was, the more continuous the solid discharge became. Moreover, although 90% of the energy supplied by gravity to the stream is dissipated by turbulence for slopes lower than 10%, particles dissipate more and more energy when the bed slope is increased, but surprisingly, the dissipation rate is nearly independent of fluid velocity. A movie is available with the online version of the paper.
Fountains impinging on a density interface
Authors: ANSONG JOSEPH K. , KYBA PATRICK J. , SUTHERLAND BRUCE R.
Published: January 2008

We present an experimental study of an axisymmetric turbulent fountain in a two-layer stratified environment. Interacting with the interface, the fountain is observed to exhibit three regimes of flow. It may penetrate the interface, but nonetheless return to the source where it spreads as a radially propagating gravity current; the return flow may be trapped at the interface where it spreads as a radially propagating intrusion or it may do both. These regimes have been classified using empirically determined regime parameters which govern the relative initial momentum of the fountain and the relative density difference of the fountain and the ambient fluid. The maximum vertical distance travelled by the fountain in a two-layer fluid has been theoretically determined by extending the theory developed for fountains in a homogeneous environment. The theory compares favourably with experimental measurements. We have also developed a theory to analyse the initial speeds of the resulting radial currents. The spreading currents exhibited two different flow regimes: a constant-velocity regime and an inertia-buoyancy regime in which the front position,R, scales with time,t, asR∼t3/4. These regimes were classified using a critical Froude number which characterized the competing effects of momentum and buoyancy in the currents.
Nonlinear global modes in inhomogeneous mixed convection flows in porous media
Authors: OUARZAZI M. N. , MEJNI F. , DELACHE A. , LABROSSE G.
Published: January 2008

The aim of this work is to investigate the fully nonlinear dynamics of mixed convection in porous media heated non-uniformly from below and through which an axial flow is maintained. Depending on the choice of the imposed inhomogeneous temperature profile, two cases prove to be of interest: the base flow displays an absolute instability region either detached from the inlet or attached to it. Results from a combined direct numerical simulations and linear stability approach have revealed that in the first case, the nonlinear solution is a steep nonlinear global mode, with a sharp stationary front located at a marginally absolutely unstable station. In the second configuration, the scaling laws for the establishment of a nonlinear global mode quenched by the inlet are found to agree perfectly with the theory. It is also found that in both configurations, the global frequency of synchronized oscillations corresponds to the local absolute frequency determined by linear criterion, even far from the threshold of global instability.
The collective dynamics of self-propelled particles
Authors: MEHANDIA VISHWAJEET , NOTT PRABHU R.
Published: January 2008

We propose a method for the dynamic simulation of a collection of self-propelled particles in a viscous Newtonian fluid. We restrict attention to particles whose size and velocity are small enough that the fluid motion is in the creeping flow regime. We propose a simple model for a self-propelled particle, and extended the Stokesian Dynamics method to conduct dynamic simulations of a collection of such particles. In our description, each particle is treated as a sphere with an orientation vector p, whose locomotion is driven by the action of a force dipole Sp of constant magnitude S0 at a point slightly displaced from its centre. To simplify the calculation, we place the dipole at the centre of the particle, and introduce a virtual propulsion force Fp to effect propulsion. The magnitude F0 of this force is proportional to S0. The directions of Sp and Fp are determined by p. In isolation, a self-propelled particle moves at a constant velocity u0p, with the speed u0 determined by S0. When it coexists with many such particles, its hydrodynamic interaction with the other particles alters its velocity and, more importantly, its orientation. As a result, the motion of the particle is chaotic. Our simulations are not restricted to low particle concentration, as we implement the full hydrodynamic interactions between the particles, but we restrict the motion of particles to two dimensions to reduce computation. We have studied the statistical properties of a suspension of self-propelled particles for a range of the particle concentration, quantified by the area fraction φa. We find several interesting features in the microstructure and statistics. We find that particles tend to swim in clusters wherein they are in close proximity. Consequently, incorporating the finite size of the particles and the near-field hydrodynamic interactions is of the essence. There is a continuous process of breakage and formation of the clusters. We find that the distributions of particle velocity at low and high φa are qualitatively different; it is close to the normal distribution at high φa, in agreement with experimental measurements. The motion of the particles is diffusive at long time, and the self-diffusivity decreases with increasing φa. The pair correlation function shows a large anisotropic build-up near contact, which decays rapidly with separation. There is also an anisotropic orientation correlation near contact, which decays more slowly with separation. Movies are available with the online version of the paper.
Electro-convection about conducting particles
Authors: YARIV EHUD , MILOH TOUVIA
Published: January 2008

A perfectly conducting spherical particle is suspended within an electrolyte solution and is exposed to a uniformly applied electric field. Using a weak-field approximation, the electro-kinetic flow is analysed for arbitrary Debye-layer thickness, the commonly employed thin-layer model emerging as a special case. We identify a scalar property which quantifies the global strength of the quadrupolar flow structure.
The multi-mode stretched spiral vortex in homogeneous isotropic turbulence
Authors: HORIUTI KIYOSI , FUJISAWA TAKEHARU
Published: January 2008

The stretched spiral vortex is identified using direct numerical simulation (DNS) data for homogeneous isotropic turbulence and its properties are studied. Its genesis, growth and annihilation are elucidated, and its role in the generation of turbulence is shown. Aside from the two symmetric modes of configurations with regard to the vorticity alignment along two spiral sheets and the vortex tube in the core region studied in previous works, a third asymmetric mode is found. One of the two symmetric modes and the asymmetric mode are created not by a conventional rolling-up of a single vortex sheet but through the interaction among several sheets. The stagnation flow caused by the two sheets converges to form recirculating flow through its interaction with the vortex along the third sheet. This recirculating flow strains and stretches the sheets. The vortex tube is formed by axial straining, lowering of pressure and the intensification of the swirling motion in the recirculating region. As a result of the differential rotation induced by the tube and that self-induced by the sheet, the vortex sheets are entrained by the tube and form spiral turns. The transition between the three modes is examined. The initial configuration is in one of two symmetric modes, but it is transformed into another set of two modes due to the occurrence of reorientation in the vorticity direction along the stretched sheets. The symmetric mode tends to be more persistent than the asymmetric mode, among the two transformed modes. The tightening of the spiral turns of the spiral sheets produces a cascade of velocity fluctuations to smaller scales and generates a strongly intermittent dissipation field. To precisely capture the spiral turns, a grid resolution with at least $k_{\rm max} \overline{\eta} \,{\approx}\, 4.0$ (kmax is the largest wavenumber, $\overline{\eta}$ is the averaged Kolmogorov scale) is required. At a higher Reynolds number, self-similar spiral vortices are successively produced by the instability cascade along the stretched vortex sheets. A cluster consisting of spiral vortices with an extensive range of length scales is formed and this cluster induces an energy cascade.
Instability of a stratified boundary layer and its coupling with internal gravity waves. Part 2. Coupling with internal gravity waves via topography
Authors: WU XUESONG , ZHANG JING
Published: January 2008

The aim of this paper is to show that the viscous shear instability identified in Part 1 is intrinsically coupled with internal gravity waves when a localized surface topography is present within a boundary layer. The coupling involves two aspects: receptivity and radiation. The former refers to excitation of shear instability modes by gravity waves, and the latter to emission of gravity waves by instability modes. Both physical processes are studied using triple-deck theory. In particular, the radiated gravity waves are found to produce a leading-order back action on the source, and this feedback effect, completely ignored in the acoustic analogy type of approach, is naturally taken into account by the triple-deck formalism. A by-product is that for certain incident angles, gravity waves are over-reflected by the boundary layer, i.e. the reflected waves are stronger than the incident waves.