bluuebunny/crossref_metadata_2025 huggingface dataset:
Elimination of Fluoroscopy Use in a Pediatric Electrophysiology Laboratory Utilizing Three‐Dimensional Mapping
Authors: SMITH GRACE , CLARK JOHN M.
Published: April 2007

Objectives: The aim of this study was to quantify fluoroscopy use in catheter ablation procedures using a three‐dimensional mapping system as the primary source of catheter guidance.

Background: Three‐dimensional mapping allows continuous visualization of the location of mapping and ablation catheter electrodes. It has been shown to decrease fluoroscopy times. However, the extent to which it can decrease fluoroscopy time has not been completely defined.

Methods: Thirty patients (mean age 12.9 years; range 4–27 years) with reentrant supraventricular tachycardia underwent catheter ablation using standard protocols. Mapping was performed using the EnSite system (St. Jude Medical, St Paul, MN, USA) in the NavX mode (NavX). Eighteen patients had AVNRT, 12 had AVRT. Fluoroscopy times were compared to an age‐matched and rhythm‐matched control population.

Results: Procedural success was achieved in 30 of 30 patients (100%). Mean procedure time was 3.27 hours (range 1.83–5.8 hours). Mean fluoroscopy time was 1.05 minutes (range 0–14.8 minutes). Twenty‐four of 30 (80%) received no fluoroscopy. Mean fluoroscopy time for the control group was 21.37 minutes (range 5.13–77.13 minutes). Thus fluoroscopy time was 95% less in the study group compared to control (1.05 ± 2.96 vs 21.37 ± 18.35 minutes, P < 0.001).

Conclusions: NavX was used to effectively guide catheters during ablation procedures resulting in a significant decrease in fluoroscopy use. In 80% of the procedures, no fluoroscopy was used. Further advances in the technology may permit additional decreases in x‐ray exposure for the 20% of patients who required it.
Ventricular Tachycardia in Non‐Compaction of Left Ventricle: Is This a Frequent Complication?
Authors: FAZIO GIOVANNI , CORRADO GIOVANNI , ZACHARA ELISABETTA , RAPEZZI CARLO , SULAFA ALI K. , SUTERA LOREDANA , PIZZUTO CATERINA , STOLLBERGER CLAUDIA , SORMANI LUCA , FINSTERER JOSEPH , BENATAR ABRAHAM , DI GESARO GABRIELE , CASCIO CATERINA , CANGEMI DEBORA , CAVUSOGLU YUKSEL , BAUMHAKEL MAGNUS , DRAGO FABRIZIO , CARERJ SCIPIONE , PIPITONE SALVATORE , NOVO SALVATORE
Published: April 2007

Background: Isolated left ventricular non‐compaction is the result of incomplete myocardial morphogenesis, leading to persistence of the embryonic myocardium. The condition is recognized by an excessively prominent trabecular meshwork and deep intertrabecular recesses of the left ventricle. Whether these intertrabecular recesses are a favorable substrate for ventricular arrhythmias is unclear. Some reports have found that the fatal ventricular arrhythmias may occur in approximately half of the patients. In this report we investigated about this association.

Methods and Results: In total we evaluated a continuous series of 238 patients affected by non‐compaction. Periodic Holter monitoring was performed every 6 months for 4 years. Only 11 patients had documented ventricular tachycardia, which was sustained in two cases and non‐sustained in nine. In no cases we observed ventricular fibrillation.

Conclusions: Non‐compaction alone does not seem to be a risk factor for malignant ventricular arrhythmias.
Implantation of a Biventricular Implantable Cardioverter Defibrillator via the Femoral Vein
Authors: JOURDIER LOUISE , SWINBURN JON , ROBERTS DAVID , CLAGUE JONATHAN
Published: April 2007

Permanent pacing with access gained via the femoral vein has been described since 1980. Here we describe implantation of a biventricular implantable cardioverter defibrillator (ICD) in a case where normal implantation using thoracic venous access was not possible due to anatomical anomalies. The advantages of this technique over epicardial pacing in such a case are discussed, as are the practical difficulties involved when applying this technique to the implantation of a biventricular ICD.
Uncommon Etiology of Syncope in a Patient with Isolated Ventricular Noncompaction
Authors: ENRIQUEZ SUSANA G. , ENTEM FELIPE R. , COBO MANUEL , OLALLA JUAN JOSE
Published: April 2007

Isolated noncompaction of left ventricular myocardium (IVNC) is categorized as an unclassified cardiomyopathy by the World Health Organization.
We describe the case of a 29‐year‐old woman who was diagnosed with IVNC after suffering two syncopes caused by an atrioventricular nodal reentrant tachycardia (AVNRT) that was successfully ablated. We report successful radiofrequency ablation in an adult with this cardiomyopathy.
Although the presence of syncope in these patients obliged us to rule out a ventricular tachycardia as the most probable etiology, our case shows how an exhaustive study is needed to look for other possible and curable causes.
Joint Analysis of Longitudinal Data with Informative Right Censoring
Authors: Liu Mengling , Ying Zhiliang
Published: April 2007

SummaryLongitudinal data arise when subjects are followed over a period of time. A commonly encountered complication in the analysis of such data is the variable length of follow‐up due to right censorship. This can be further exacerbated by the possible dependency between the censoring time and the longitudinal measurements. This article proposes a combination of a semiparametric transformation model for the censoring time and a linear mixed effects model for the longitudinal measurements. The dependency is handled via latent variables which are naturally incorporated. We show that the likelihood function has an explicit form and develops a two‐stage estimation procedure to avoid direct maximization over a high‐dimensional parameter space. The resulting estimators are shown to be consistent and asymptotically normal, with a closed form for the variance–covariance matrix that can be used to obtain a plug‐in estimator. Finite sample performance of the proposed approach is assessed through extensive simulations. The method is applied to renal disease data.
Proximity Model for Expression Quantitative Trait Loci (eQTL) Detection
Authors: Gelfond Jonathan A. L. , Ibrahim Joseph G. , Zou Fei
Published: April 2007

SummaryExpression quantitative trait loci (eQTL) are loci or markers on the genomes that are associated with gene expression. It is well known to biologists that some (cis) genetic influences on expression occur over short distances on the genome while some (trans) influences can operate remotely. We use a log‐linear model to place structure on the prior probability for genetic control of a transcript by a marker locus so that the loci that are closest to a transcript are given a higher prior probability of controlling that transcript to reflect the important role that genomic proximity can play in the regulation of expression. This proximity model is an extension of the mixture over marker (MOM) model for the simultaneous detection ofcisandtranseQTL of Kendziorski (Kendziorski et al., 2006,Biometrics62(1), 19–27). The genomic locations of the transcripts are used to improve the accuracy of the posterior distribution for the location of the eQTL. We compare the MOM method to our extension with both simulated data and data sets of recombinant inbred mouse lines. We also discuss an extension of the MOM method to model multiple eQTLs, and find that many transcripts are likely associated with more than one eQTL.
Applications and Extensions of Chao's Moment Estimator for the Size of a Closed Population
Authors: Rivest Louis‐Paul , Baillargeon Sophie
Published: April 2007

Summary This article revisits Chao's (1989, Biometrics45, 427–438) lower bound estimator for the size of a closed population in a mark–recapture experiment where the capture probabilities vary between animals (model Mh). First, an extension of the lower bound to models featuring a time effect and heterogeneity in capture probabilities (Mth) is proposed. The biases of these lower bounds are shown to be a function of the heterogeneity parameter for several loglinear models for Mth. Small‐sample bias reduction techniques for Chao's lower bound estimator are also derived. The application of the loglinear model underlying Chao's estimator when heterogeneity has been detected in the primary periods of a robust design is then investigated. A test for the null hypothesis that Chao's loglinear model provides unbiased abundance estimators is provided. The strategy of systematically using Chao's loglinear model in the primary periods of a robust design where heterogeneity has been detected is investigated in a Monte Carlo experiment. Its impact on the estimation of the population sizes and of the survival rates is evaluated in a Monte Carlo experiment.
Approximations for Expected Generation Number
Authors: Cole D. J. , Ridout M. S. , Morgan B. J. T. , Byrne L. J. , Tuite M. F.
Published: April 2007

Summary A deterministic formula is commonly used to approximate the expected generation number of a population of growing cells. However, this can give misleading results because it does not allow for natural variation in the times that individual cells take to reproduce. Here we present more accurate approximations for both symmetric and asymmetric cell division. Based on the first two moments of the generation time distribution, these approximations are also robust. We illustrate the improved approximations using data that arise from monitoring individual yeast cells under a microscope and also demonstrate how the approximations can be used when such detailed data are not available.
Sol–Gel Synthesis and Photocatalytic Activity of CeO2/TiO2 Nanocomposites
Authors: Yang Huaming , Zhang Ke , Shi Rongrong , Tang Aidong
Published: April 2007

Uniform CeO2/TiO2 composite nanoparticles with different Ce/Ti molar ratios have been successfully synthesized via the sol–gel method. The samples were characterized using differential thermal analysis (DTA), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and transmission electron microscopy (TEM). The surface state analysis by means of X‐ray photoelectron spectroscopy (XPS) shows that the Ti element mainly exists as a chemical state of Ti4+, while the Ce element exists as a mixture of Ce3+ and Ce4+ oxidation states. The photocatalytic degradation of methyl orange (MeO) in CeO2/TiO2 suspension was investigated. The results indicate that the CeO2/TiO2 nanocomposites show higher photocatalytic activity than pure TiO2. Photodegradation of MeO can be improved by increasing the Ce/Ti molar ratio in the initial 15 min.
In Situ Formation of Silicon Carbide Nanofibers on Cordierite Substrates
Authors: Jayaseelan Daniel D. , Lee William E. , Amutharani Devaraj , Zhang Shaowei , Yoshida Katsumi , Kita Hideki
Published: April 2007

Twenty‐five years of diesel particulate filter (DPF) developments have shown that high‐volume ceramic materials are well suited for the harsh requirements of exhaust after treatment. Nevertheless, problems regarding filter reliability and durability associated with the regeneration of the filter have limited their serious application until only recently. To extend useful filter life, the present study has examined the growth of silicon carbide (SiC) nanofibers by a simple carbothermal reduction process on cordierite support surfaces using cheap raw materials such as kaolin, talc, and carbon black. Transmission electron microscopy confirms the crystalline (β‐SiC) nature of the nanofibers (10–20 nm diameter). The growth of these nanofibers increases the support‐specific surface area restricting the agglomeration of noble metal catalyst particles that otherwise occurs in wash‐coat sintering. As a result, fewer particles are needed to perform the catalyst role (at reduced cost) and the support structure can host the catalyst for prolonged times at higher temperatures. As the future will see increasing economic competition in filter fabrication routes and materials, this new design of catalytic DPF promises to play a significant role.
Refinement of the α‐Phase Area in the Yb‐SiAlON System
Authors: Fox Kevin M. , Hellmann John R. , Angelone Mark S. , Yeckley Russell L.
Published: April 2007

The composition and lattice parameters of several Yb‐SiAlON materials are reported. Electron microprobe analysis was used to measure the compositions of each phase, as this technique avoided the peak overlap problems encountered when using energy‐dispersive spectroscopy. A refined set of equations relating the composition of Yb‐α‐SiAlON to its lattice parameters is presented. The amount of oxygen substitution (n value) in α‐SiAlON has an effect on lattice parameters that is almost as strong as the amount of Al and Yb substitution (m value). The α‐SiAlON phase stability region is shown to extend much closer to the Si3N4‐4/3(AlN:Al2O3) line than reported previously.
Physicochemical Mechanism for the Continuous Reaction of γ‐Al2O3‐Modified Aluminum Powder with Water
Authors: Deng Zhen‐Yan , Ferreira José M. F. , Tanaka Yoshihisa , Ye Jinhua
Published: April 2007

Previous experiments showed that γ‐Al2O3‐modified Al powder could continuously react with water and generate hydrogen at room temperature under atmospheric pressure. In this work, a possible physicochemical mechanism is proposed. It reveals that a passive oxide film on Al particle surfaces is hydrated in water. OH− ions are the main mobile species in the hydrated oxide film. When the hydrated front meets the metal Al surface, OH− ions react with Al and release H2. Because of the limited H‐soluble capacity in small Al particles and the low permeability of the hydrated oxide film toward H+ species, H2 molecules accumulate and form small H2 gas bubbles at the Al:Al2O3 interface. When the reaction equilibrium pressure in H2 bubbles exceeds a critical gas pressure that the hydrated oxide film can sustain, the film on the Al particle surfaces breaks and the reaction of Al with water continues. As the surface oxide layer on modified Al particles has a lower tensile strength, the critical gas pressure in H2 bubbles is lower so that under an ambient condition, the reaction of modified Al particles with water is continuous. The proposed mechanism was further confirmed by a new experiment showing that the as‐received Al powder could continuously react with water at temperatures above 40°C and under low vacuum, because the vacuum makes the critical gas pressure in H2 bubbles decrease as well.
Crystal Structure and Dielectric Properties of LaYbO3
Authors: Feteira Antonio , Gillie Lisa J. , Elsebrock Ralf , Sinclair Derek C.
Published: April 2007

The crystal structure and dielectric properties of LaYbO3 ceramics prepared by the mixed‐oxide route have been investigated. Rietveld refinements performed on X‐ray and neutron diffraction data show the room‐temperature structure to be best described by the orthorhombic Pnma space group [a=6.02628(9) Å, b=8.39857(11) Å, and c=5.82717(7) Å; Z=4, and theoretical density, Dx=8.1 g/cm3] in agreement with electron diffraction experiments. LaYbO3 ceramics fired at 1600°C for 4 h attain ∼97% of Dx and their microstructures consist of randomly distributed equiaxed grains with an average size of ∼8 μm. Conventional transmission electron microscopy shows densification to occur in the absence of a liquid phase and reveals domain‐free grains. The relative permittivity, ɛr, of LaYbO3 ceramics at radio frequencies is ∼26 in the range ∼10–300 K; however, a small dielectric anomaly is detected at ∼15 K. At room temperature and microwave frequencies, LaYbO3 ceramics exhibit ɛr∼26, Q×fr∼20 613 GHz (at 7 GHz), and τf∼−22 ppm/K. Q×fr show complex subambient behavior, decreasing from a plateau value of ∼20 000 GHz between ∼300 and 200 K to a second plateau value of ∼6000 GHz at ∼90 K before decreasing to <1000 GHz at ∼10 K. The large decrease in Q×fr at low temperature may be related to the onset of antiferromagnetism at ∼2.7 K.1
Low‐Temperature Synthesis and Growth of Hexagonal Boron‐Nitride in a Lithium Bromide Melt
Authors: Gu Yunle , Zheng Mingtao , Liu Yingliang , Xu Zilin
Published: April 2007

The synthesis and growth of hexagonal boron‐nitride crystallites at low temperature were investigated by carrying out in a lithium bromide (LiBr) melt in 600°–700°C. Transmission electron microscopy study showed that the product obtained at 650°C was composed of two‐dimensional plates having an average thickness of about 80 nm and widths from about 400 nm to several micrometers. The molten salt was found to have a strong effect on the crystal growth. The morphology of the crystallites changed from spherical particles to two‐dimensional plates when LiBr was used as a crystallization medium. Products were also characterized by X‐ray powder diffractions, Fourier Transformed infrared, FESEM/energy dispersive X‐ray spectroscopy, and selected area electron diffraction. Possible formation mechanism was also discussed.
Seeded Crystallization of Leucite
Authors: Zhang Yi , Li Bin , Rao Pinggen , Lü Ming , Wu Jianqing
Published: April 2007

The leucite crystallization kinetics from a hydrothermally derived precursor seeded with nano‐crystalline leucite was investigated by X‐ray diffraction and non‐isothermal differential thermal analysis. The nano‐crystalline leucite was prepared by high‐energy milling of high‐purity leucite powder and the leucite precursor was prepared by the hydrothermal method of silica sol, aluminum nitrate, and potassium nitrate. After the seeds were introduced, the crystallization temperature of the precursor was lowered by 100°C and the transition phase kalsilite did not appear during the crystallization process. When the seeded precursor was heat treated at 700°C, a small amount of cubic leucite was stabilized to room temperature. The seeded precursor showed an exothermic peak between 800° and 920°C under different heating rates. The activation energy for the growth of leucite from the seeded precursor was 256(SD9) kJ/mol.
Microwave Dielectric Properties of a New A5B4O15‐Type Cation‐Deficient Perovskite Ba2La3Ti3TaO15
Authors: Fang Liang , Yu Qian , Zhang Hui , Hu C. Z. , Wu B. L.
Published: April 2007

High dielectric constant and low loss ceramics with composition Ba2La3Ti3TaO15 have been prepared by a conventional solid‐state ceramic route. This compound adopts A5B4O15 cation‐deficient hexagonal perovskite structure. The dielectric properties of dense ceramics sintered in air at 1520°C have been characterized at microwave frequencies. It shows a relative dielectric constant of ∼45, quality factor Qu×f of ∼26 828 GHz and temperature variation of resonant frequency of −0.97 ppm/°C.
Coupling of Phosphates on Alumina Surfaces for Bioactivation
Authors: Kaltenborn Nadine , Sax Michael , Müller Frank A. , Müller Lenka , Dieker Henning , Kaiser Arno , Telle Rainer , Fischer Horst
Published: April 2007

This paper reports on a new surface treatment, coupling phosphates on alumina surfaces for bioactivation. Alumina samples were treated in monoaluminumphosphate solution at 1400°C. Strongly coupled aluminum phosphates due to the treatment were proved by X‐ray diffraction and infrared spectroscopy. Contact angle measurements proved the hydrophilic nature of the treated surface. In vitro tests in simulated body fluid indicated a bioactive behavior by means of apatite‐forming ability. Such functionalized alumina ceramics imply the potential for a new class of bioactive high‐strength ceramic implant materials, due to a pronounced affinity of bioactive phosphate groups to particular amino acid sequences of proteins.
Sub‐Critical Crack Growth Behavior of a Low‐Temperature Co‐Fired Ceramic
Authors: Tandon Rajan , Newton Clay S. , Monroe Saundra L. , Glass S. Jill , Roth Christine J.
Published: April 2007

The strength of sintered low‐temperature co‐fired ceramic (LTCC) disks was measured under dry (<2% relative humidity [RH]) and wet (98% RH) conditions, using ring‐on‐ring, biaxial‐flexure testing in the stressing rate range of 0.002–2 MPa/s. The empirical sub‐critical crack growth parameters, n and A, were calculated. The values of the parameters in the wet environment were higher than in the dry environment. It is argued that the high RH n value is more representative of material behavior. Results of fractographic examination are reported and expected lifetime and safe design stresses for LTCC are calculated.
Microstructure, Density, and Dielectric Properties of Lead‐Free (K0.44Na0.52Li0.04)(Nb0.96−xTaxSb0.04)O3 Piezoelectric Ceramics
Authors: Chang Yunfei , Yang Zupei , Wei Lingling
Published: April 2007

Lead‐free (K0.44Na0.52Li0.04) (Nb0.96−xTaxSb0.04)O3 piezoelectric ceramics were prepared by the conventional solid‐state sintering method. The grain growth of the ceramics was inhibited and the relative density was improved with Ta substituting for Nb. Increasing x led to different variations of dielectric properties before and after poling, and prevented the occurrence of orthorhombic–tetragonal phase transition (at To−t). All the ceramics show an intermediate relaxor‐like behavior between normal and ideal relaxor ferroelectrics. Significantly enhanced dielectric and piezoelectric properties were obtained in the ceramics with x=0.20. The ceramics are very promising lead‐free materials for electromechanical device applications.
Lead‐Free SrBi4Ti4O15 and Bi4Ti3O12 Material Fabrication Using the Microwave‐Assisted Molten Salt Synthesis Method
Authors: Hao Hua , Liu Han‐xing , Liu Yang , Cao Ming‐he , Ouyang Shi‐xi
Published: April 2007

In this paper, the microwave‐assisted molten salt method (MAMSS) and molten salt method (MSS) were used to synthesize SrBi4Ti4O15 (SBT). The phase constitution was determined by powder X‐ray diffraction and the microstructure of powder was examined by scanning electron microscopy. In contrast to the conventional MSS method, MAMSS produces more distinct plate‐like grains and synthesizes both SBT and Bi4Ti3O12 (BTO) at 600°C with a 30‐min soaking time. The increase of temperature and soaking time can make the plate‐like grains of BTO more distinct.
Effect of Residual Stress on the Luminescence Lifetime of R‐Line Emission from Polycrystalline Alumina Formed by Oxidation
Authors: Margueron Samuel H. , Clarke David R.
Published: April 2007

In contrast to the simple exponential decay of the luminescence lifetime of the R lines observed from stressed and unstressed single crystals, the luminescence decay from polycrystalline alumina, formed by the oxidation of a ferritic FeCrAlY alloy, is found to fit a stretched exponential. A stretch exponential is found to fit all the luminescence decays in the polycrystalline alumina and the dependence of the stretch parameters under biaxial residual stress and under uniaxial stress is reported. The mean lifetime varies linearly with the residual stress, as monitored by the R2‐line shift. Using established piezospectroscopic relations, the stress dependence of the lifetime is found to be one‐third of the hydrostatic pressure under uniaxial stress and two thirds under biaxial stresses. In contrast, the stretch exponent doesnt vary with stress.
Electrical Properties of Silica‐Based Nanocomposites with Multiwall Carbon Nanotubes
Authors: Guo Shuqi , Sivakumar Ramasamy , Kitazawa Hideaki , Kagawa Yutaka
Published: April 2007

Fully dense multiwall carbon nanotubes (MWCNT)/SiO2 nanocomposites with MWCNTs contents of 5 and 10 vol% have been processed by spark plasma sintering, and the electrical conductivities of the nanocomposites were evaluated at temperatures ranging from 5 to 300 K. It has been found that the incorporation of MWCNTs converted an insulating silica nanoceramic into metallically conductive composites. The room‐temperature conductivities of the nanocomposites, with over 14 orders of magnitude compared with pure silica, are in the range of 8 and 65 S/m. Also, it was interestingly found that the conductivity increased linearly with temperature from 5 to 300 K.
Cryogenic Microwave Dielectric Properties of Sintered (Zr0.8Sn0.2)TiO4 Doped with CuO and ZnO
Authors: Jacob M. V. , Pamu D. , James Raju K. C.
Published: April 2007

The effect of CuO on the sintering temperature, microstructure, and the microwave dielectric properties of (Zr0.8Sn0.2)TiO4 (ZST) has been investigated. The microwave dielectric properties of the ZST ceramics have been measured at cryogenic temperatures (15–290 K). The crystallite sizes of the sintered ZST ceramics are in the 30–50‐nm range. The addition of CuO effectively reduced the sintering temperature to 1300°C due to the liquid‐phase effects. The addition of CuO did not cause any secondary phases up to 1.5 wt% of CuO. It is found that the quality factor (Q) of the sample without CuO decreased with an increase in temperature, whereas the samples with the addition of CuO up to 1.0 wt% showed less dependence on temperature at cryogenic temperatures. The microwave dielectric properties of the ZST ceramics measured at cryogenic temperatures exhibited a Q factor of 15 000 for pure ZST and 11 800 for ZST with 0.5 wt% of CuO at 15 K. The increase in Q factor at cryogenic temperatures can be attributed to the reduction in both intrinsic and extrinsic losses in the ZST ceramics.
Oxidation Resistance Coating of LSM and LSCF on SOFC Metallic Interconnects by the Aerosol Deposition Process
Authors: Choi Jong‐Jin , Lee Joo‐Hee , Park Dong‐Soo , Hahn Byung‐Dong , Yoon Woon‐Ha , Lin Hua‐Tay
Published: April 2007

Conductive La0.8Sr0.2MnO3 (LSM) and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) layers with a thickness of ∼10 μm were deposited on ferritic stainless steel (SS) by the aerosol deposition method, for use as an oxidation resistance‐coating layer in the metallic interconnector of a solid oxide fuel cell. The coated layers were fairly dense without pores or cracks, and maintained good adhesion even after oxidation at 800°C for 100 h. The surface of the bare SS after annealing at 800°C for 100 h was covered with Cr2O3 and Fe3O4 oxide scales, and the electrical conductivity was sharply decreased. However, the LSM‐ and LSCF‐coated SSs showed a surface microstructure with almost no oxidation and maintained good electrical conductivity after annealing at 800°C for 100 h. The area‐specific resistance (ASR) of LSM‐ and LSCF‐coated alloys after 100 h of oxidation at 800°C was 20.6 and 11.7 mΩ·cm2, respectively.
Melatonin as a potential antihypertensive treatment
Authors: Simko Fedor , Paulis Ludovit
Published: April 2007

Abstract: The number of patients with well‐controlled hypertension is alarmingly low worldwide and new approaches to treatment of increased blood pressure (BP) are being sought. Melatonin has a role in blood pressure regulation. The nighttime production of melatonin is found to be reduced in hypertensive individuals. Administration of melatonin decreased BP in several animal models of hypertension, in healthy men and women, and in patients with arterial hypertension. Most promising results were achieved in patients with non‐dipping nighttime pressure, in which the circadian rhythm of BP variation is disturbed. Several potential mechanisms of BP reduction are considered. Melatonin can, via its scavenging and antioxidant nature, improve endothelial function with increased availability of nitric oxide exerting vasodilatory and hypotensive effects. Melatonin seems to interfere with peripheral and central autonomic system, with a subsequent decrease in the tone of the adrenergic system and an increase of the cholinergic system. Melatonin may act on BP also via specific melatonin receptors localized in peripheral vessels or in parts of central nervous system participating in BP control. With a large clinical trial using melatonin in hypertension treatment, many important questions could be answered, such as the dose of melatonin and regimen of its application, the choice of patients with greatest possible benefit from melatonin treatment, the potential of anti‐remodeling effect of melatonin and the interaction of melatonin with other antihypertensive drugs.
Melatonin and the human hippocampus, a time dependant interplay
Authors: Gorfine Tali , Zisapel Nava
Published: April 2007

Abstract:  Melatonin serves as a signal of darkness and participates in sleep/wake regulation. Animal studies demonstrated effects of melatonin in the hippocampus, particularly suggesting involvement in synaptic plasticity. We used functional magnetic resonance imaging to identify and investigate effects of melatonin in the human hippocampus. Activity in the hippocampal complex during a memory task was examined at 22:00 hr (when endogenous melatonin levels are normally increasing) and compared with 16:00 hr (when endogenous melatonin levels are minimal). The relationship between observed activation patterns and endogenous melatonin was assessed. Finally, the effects of exogenous melatonin administered at 22:00 hr were studied in a double‐blind, placebo‐controlled crossover manner. Our findings indicate that activation in the left hippocampus at 22:00 hr is significantly reduced compared with afternoon hours compatible with diurnal variation in hippocampal activity. Exogenous melatonin further reduced activation in this region, only in subjects who already crossed the melatonin onset phase at this hour and in correlation with endogenous melatonin levels. As such an effect was not demonstrated with afternoon administration of melatonin, a time depended effect is suggested. Contrary, activation in the left parahippocampus at 22:00 hr was higher in subjects that crossed the melatonin onset phase. Parahippocampal activation correlated with individual endogenous melatonin levels and was not further affected by exogenous melatonin. These results demonstrate that memory related activation in the hippocampus and parahippocampus are affected by time of day and melatonin in a differential manner and may implicate the circadian clock and melatonin in human memory processing during the night.
EFFECT OF FLOW RATES ON THE STORAGE PROPERTIES OF PALM OIL‐BASED MARGARINE
Authors: MISKANDAR M. S. , MAN Y. B. CHE , YUSOFF M. S. A. , RAHMAN R. ABD
Published: April 2007

The effect of flow rates on the production of palm oil‐based margarine was studied. The flow rates studied were 15, 30, and 45 kg/h, with other parameters such as emulsion and tube cooler temperature, speed of the tube cooler, intermediate crystallizer and pin worker unit kept constant. The margarines were significantly different in their consistencies, solid fat content (SFC) and polymorphic behavior during processing and storage at 28C. The SFCs in the tube cooler and the pin worker units corresponded with the flow rates, while crystallization affected the temperatures of the product during processing. Margarine production at a flow rate of 30 kg/h afforded the highest margarine consistency during storage, while 45 kg/h gave the lowest. However, the highest and lowest SFC was from samples of 30 kg/h and 15 kg/h, respectively. The transformation of β to β crystal had occurred at the second, third and fourth week of storage in samples of 45, 15 and 30 kg/h, respectively.
ANTIOXIDANT ACTIVITIES OF ENZYMATIC EXTRACTS FROM AN EDIBLE SEAWEED SARGASSUM HORNERI USING ESR SPECTROMETRY
Authors: PARK PYO‐JAM , SHAHIDI FEREIDOON , JEON YOU‐JIN
Published: April 2007

The antioxidant activity of water‐soluble natural extracts from an edible seaweed, Sargassum horneri, was evaluated by examining the radical scavenging activities of the extracts of hydrolyzates from S. horneri on 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH), hydroxyl and alkyl radicals. A spin‐trapping electron spin resonance (ESR) spectrophotometer was employed and the results were compared for their ESR signal intensity. The brown seaweed S. horneri was enzymatically hydrolyzed to prepare water‐soluble extracts by five carbohydrases (AMG, Celluclast, Termamyl, Ultraflo and Viscozyme) and five proteases (Alcalase, Flavourzyme, Kojizyme, Neutrase, Protamex). The extracts so prepared exhibited strong scavenging activity on DPPH, hydroxyl and alkyl radicals. The scavenging activity of the radicals increased with increased concentration of the extracts. The scavenging results were higher or similar for hydroxyl and alkyl radicals, and lower for DPPH radical compared with vitamin C as a reference. Viscozyme and Alcalase extracts were superior and scavenged radicals examined better than the extracts prepared by other carbohydrases and proteases.
ENZYMATIC SYNTHESIS OF THEAFLAVINS AND EPITHEAFLAVIC ACID FROM TEA CATECHINS AND THEIR ANTIOXIDANT ACTIVITY
Authors: JHOO JIN‐WOO , SANG SHENGMIN , WEI GUOR‐JIEN , LEE TUNG CHING , ROSEN ROBERT T. , HO CHI‐TANG
Published: April 2007

A number of in vitro and in vivo studies have demonstrated that black tea polyphenols have significant biological activities, including antioxidant, antiinflammatory and anticancer activity. The theaflavins have received attention as one of responsible components for biological activities of black tea. However, little information is available for the biological activity of individual theaflavins and minor components in black tea. In the present study, theaflavins and epitheqflavic acid were synthesized from their parent flavan‐3‐ols catechins using an enzymatic oxidation method and employing crude polyphenol oxidase from banana fruit. The compounds were isolated using column chromatographic methods, and their structures confirmed by 1H‐NMR and APCI‐MS. The peroxyl radical scavenging activities of theaflavins and epitheaflavic acids were measured using a modified ORAC method. The results indicated that theaflavins have higher peroxyl radical scavenging activity than EGCG. The hierarchy of radical scavenging activity of theaflavins, epitheaflavic acid and related compounds were in the order of: theaflavin‐3, 3′‐digallate ∼ theflavin‐3‐gallate ∼ theaflavin‐3′‐gallate ∼ theaflavin > epitheaflavic acid > EGCG > purpurogallin.
LIPID CONTENT AND FATTY ACID COMPOSITION IN THE GREEN‐LIPPED MUSSEL PERNA VIRIDIS (L.)
Authors: CHAN K. Y. , GAO Q. F. , YIP K. M. , WONG W. H. , SHIN P. K. S. , CHEUNG S. G.
Published: April 2007

The lipid content and fatty acid profile in soft tissue of the green‐lipped mussel Perna viridis, a widely distributed tropical and subtropical bivalve species, were investigated. The total and neutral lipid contents were 6.17 ± 0.71 and 2.71 ± 0.42 mg per 100 mg dw, respectively. The content of docosahexaenoic acid (DHA, C22:6n‐3) was 24.38 ± 2.50 mg/g dw whereas eicosapentaenoic acid (EPA, C20:5n‐3) was present at 12.29 ± 2.12 mg/g dw. These two fatty acids were also at the top high percentage among all the fatty acids, with 38.06 ± 0.86% and 17.89 ± 1.24% (w/w) in total lipids and 34.64 ± 2.74% and 20.33 ± 1.05% (w/w) in neutral lipids, respectively. Therefore, green‐lipped mussel is a rich source of DHA and EPA, the two n‐3 polyunsaturated fatty acids that are beneficial to human health and nutrition.
EFFECTS OF SESAME LIGNAN EXTRACT ON LINOLEIC ACID, LIPID OXIDATION, COLOR AND TEXTURAL PROPERTIES OF GROUND PORK, AND SAUSAGE PRODUCTS
Authors: CHO S. H. , PARK B. Y. , KIM J. H. , PARK K. M. , RYU S. N. , LEE J. M.
Published: April 2007

Sesame lignan extract was prepared from roasted sesame oil and added at 0.02, 0.05, 0.10 and 0.20% (w/w) to linoleic acid and ground pork products. Cooked ground pork containing more than 0.02% of lignan extract showed TBA values lower than those containing butylated hydroxyanisole (BHA) during storage. Sausages containing 0.05% of lignan extract had lower thiobarbituric acid (TBA) values when stored at 4C for 14 days; they also showed higher CIE color values than the control meat sample (P < 0.05). There were no differences in textural properties such as hardness, cohesiveness and chewiness between the control and the sausages containing lignan extract when determined by Instron Testing Machine. Thus, lignan extract prepared from roasted sesame oils was highly antioxidative when used in cooked ground pork at > 0.02% or in sausages at > 0.05%.
EFFECT OF KOSHERING AND HYDRODYNAMIC PRESSURE ON BEEF COLOR, ODOR, AND MICROBIAL LOADS1
Authors: HOLZER Z. , BERRY B.W. , CAMPBELL A.M. , SPANIER A.M. , SOLOMON M.B.
Published: April 2007

Vacuum packaged koshered (salted) meat typically undergoes a rapid color change (turning brown) with the formation of objectionable odor during refrigeration. Alterations in muscle structure have been suggested to affect the oxidative activity of salt. The hydrodynamic pressure (HDP) has been shown to physically disrupt portions of myofibrils without distorting the physical shape of the piece of meat, which may alter the effect of the kosher processing on fresh meat properties. The objective of this study was to assess the effects of the koshering process and hydrodynamic pressure (HDP), either alone or in combination, on pH, microbial growth, color and odor properties of beef. Treatments were: (1) control (C); (2) koshering process (salted = S); (3) hydrodynamic pressure treated (H); (4) the combination of koshering followed by HDP treatment (SH). The H treatment was more effective in inhibiting the normal microflora than either the S or the combination of S with H. After 14 days of storage, S samples had greater than 80% surface discoloration (brown color) compared to less than 40% discoloration on the surface for the C, H and SH samples. The H treatment reduced the surface discoloration of koshered (salted) meat samples to a level similar to that of the control. It appears that hydrodynamic pressure treatment may diminish the undesirable pro‐oxidant effects (discoloration) of koshering (salting) beef.
IN‐HOME CONSUMER EVALUATIONS OF FOUR LAMB RETAIL CUTS
Authors: MADDOCK T.D. , MCKENNA D.R. , SAVELL J.W.
Published: April 2007

An in‐home lamb study evaluated ratings from lamb consumers as influenced by cut (blade chop, rib chop, loin chop or leg chop), preparation method (indoor/outdoor grill, broil/oven roasted, pan‐broil/pan‐fry or other), and degree of doneness (medium rare or less, medium, medium well or more). Consumers in Dallas and Houston, Texas (n = 60 households) evaluated each cut for Overall‐like (OLIKE), Tenderness (TEND), Juiciness (JUIC), Flavor Intensity (IFLAV), and Flavor Desirability (DFLAV) using 10‐point scales (10 = extreme like, extremely tender, extremely juicy, extremely intense, and extremely desirable; 1 = extreme dislike, extremely tough, extremely dry, extremely bland, and extremely undesirable). No two‐way or three‐way interactions were observed between cut, preparation method and degree of doneness. Type of cut influenced (P < 0.05) palatability as consumers gave rib and loin chops higher ratings than chops from the blade or leg for OLIKE, TEND, JUIC, and DFLAV. Preparation method tended (P = 0.0565) to influence IFLAV with pan‐broiled/pan‐fried chops receiving higher ratings than grilled chops or chops cooked using “other” methods. Degree of doneness affected (P < 0.05) JUIC and tended (P = 0.0639) to affect TEND with chops that were cooked to lower degrees of doneness rated higher. Correlation data showed that OLIKE was highly correlated with TEND (r = 0.82), DFLAV (r = 0.82), and JUIC (r = 0.76), but did not have a strong relationship with IFLAV (r = 0.25). This information provides some insight into factors driving consumer evaluations of lamb.
QUALITY OF NUGGETS PREPARED FROM FRESH AND SMOKED SPENT LAYER CHICKEN MEAT
Authors: MODI V.K. , MAHENDRAKAR N.S. , SACHINDRA N.M. , RAO D. NARASIMHA
Published: April 2007

Nuggets were prepared from fresh and smoked meats of spent layer chicken of age approximately 18 months, packed in polyethylene bags and stored at ‐18 ± 2C for 6 months. Thawed nuggets were fried on hot pan coated with refined sunflower oil and product quality was evaluated. Nuggets from smoked chicken had lower (P ±0.05) moisture and higher fat contents and lower weight loss on frying compared to fresh meat nuggets. Free fatty acid (FFA expressed as percent of oleic acid) increased from 3.6 to 3.9 and 3.2 to 3.7, and thiobarbituric acid (TBA) values (mg malonaldehyde/kg sample) increased from 0.90 to 1.19 and 0.63 to 0.71 for fresh and smoked meat nuggets, respectively, during frozen storage for 6 months. Shrinkage in product diameter on frying ranged from 4.6 to 5.0%. Warner‐Bratzler shear values ranged from 0.89 to 1.28 lbs for all products stored frozen up to 6 months. Sensory quality scores for smoked meat nuggets were significantly (P ±0.05) higher, except for juiciness (P ≥0.05), than for fresh meat nuggets. Smoked chicken meat produced better nugget products compared to fresh meat as indicated by lower FFA and TBA values and better sensory quality attributes. Products packed in polyethylene bags can be stored at ‐18 ≥ 2C for up to 6 months without marked deterioration in product quality.
BIOMEMS AND NANOTECHNOLOGY‐BASED APPROACHES FOR RAPID DETECTION OF BIOLOGICAL ENTITIES
Authors: BHATTACHARYA SHANTANU , JANG JAESUNG , YANG LIJU , AKIN DEMIR , BASHIR RASHID
Published: April 2007

In recent years, the areas of Bio‐Microelectromechanical Systems (BioMEMS) and nanotechnology have gained a high level of prominence and have become almost inseparable with biological applications including detection, diagnostics, therapeutics and tissue engineering. This article reviews some of the current state‐of‐the‐art interdisciplinary research from these fields, especially focusing on rapid detection of pathogens and microorganisms, a critical area of importance to food safety, clinical diagnostics and related applications.
EVALUATION OF THE CHARACTER IMPACT ODORANTS IN SKIM MILK POWDER BY SENSORY STUDIES ON MODEL MIXTURES
Authors: KARAGÜL‐YÜCEER Y. , DRAKE M.A. , CADWALLADER K.R.
Published: April 2007

The objective of this study was to verify key aroma‐active compounds responsible for reconstituted fresh skim milk powder (SMP) aroma using threshold analysis, odor activity values, and model systems. Twelve odor‐active compounds of SMP and one odor‐active compound from fluid milk were selected based on flavor dilution factors from gas chromatography‐olfactometry. Thresholds for the 13 odor‐active compounds were identified using five‐set ascending forced choice threshold analysis in odor‐free water and fluid skim milk. Model systems were prepared using rehydrated milk retentate (RMR). The aroma of each model was evaluated by descriptive sensory analysis and by difference‐from‐control testing using a trained panel. The aroma of reconstituted fresh SMP and liquid skim milk were used as controls. Models containing a mixture of twelve of the thirteen chemicals had the most similar odor characteristics to rehydrated SMP aroma (9.0/10) indicating that these compounds constitute the character impact odorants of rehydrated fresh SMP.
SENSORY CHARACTERISTICS OF CHEMICAL COMPOUNDS POTENTIALLY ASSOCIATED WITH BEANY AROMA IN FOODS1
Authors: VARA‐UBOL SUNTAREE , CHAMBERS EDGAR , CHAMBERS DELORES H.
Published: April 2007

The sensory characteristic “beany” is a limiting factor in introducing soy products to many consumers in western cultures. This research described sensory properties of beany flavor and described sensory odor characteristics of 19 chemicals that have been associated with beany aroma and flavor in previous literature. Seven concentrations varying from 1 to 100,000 ppm of each chemical (if soluble in propylene glycol) were examined by a five member trained descriptive panel. The panel described beany as having multiple attributes. Musty/earthy, musty/dusty, sour aromatics, and characterizing attributes such as green/pea pod, nutty, or brown collectively imparted beany aroma and flavor of most beans. Starchy flavor and powdery texture also were intrinsically associated with beany in bean product samples. Some chemicals tested were not beany at any level tested. Three alcohols, two ketones, one aldehyde, and one pyrazine exhibited beany characteristics (green/peapod or brown) only at low concentrations, generally 1‐10 ppm.
A COMPARISON OF CATEGORY AND LINE SCALES UNDER VARIOUS EXPERIMENTAL PROTOCOLS
Authors: JEON SEON‐YOUNG , O'MAHONY MICHAEL , KIM KWANG‐OK
Published: April 2007

Judges were required to rate the total intensity of NaCl solutions and the sweetness of orange flavored beverages using a variety of unstructured category and line scales. Discrimination errors were noted for each type of scale. No strong differences were observed in discrimination between category and line scales although a 20‐point category scale incurred fewer discrimination errors than 9‐point category and line scales. Allowing judges to retaste stimuli and review and modify their scores reduced discrimination errors.
RELATIONSHIP BETWEEN ORAL AND NONORAL EVALUATION OF TEXTURE IN ACID MILK GELS
Authors: PEREIRA R.B. , SINGH H. , JONES V.S. , MUNRO P.A.
Published: April 2007

The objectives of this study were to compare oral and nonoral sensory evaluation for discrimination of texture of acid skim milk gels and to establish whether nonoral attributes could be correlated to the oral perception of texture. Trained panelists (n = 13) identified 11 nonoral (visual and in‐hand) and 4 oral attributes during a preliminary profiling session that could be used to discriminate textures (P < 0.001) in a range of acid gels prepared with different solid contents and heat treatment of the milks. Both methods of sensory appraisal were found to discriminate between gels. Correlation analysis showed high interrelationship between individual oral and nonoral attributes (P < 0.01). Principal component analysis revealed that all 4 oral attributes could be combined into one single attribute (PC1), with equal relative importance of the individual attributes in explaining the variance in the oral sensory data set. Canonical correlation analysis revealed good correlation between the oral and nonoral set of attributes (R2 > 87.5%).
A 2‐Step Cooking Method of Searing and Hot Water Pasteurization to Maximize the Safety of Refrigerated, Vacuum Packaged, Chicken Breast Meat
Authors: Enns D.K. , Crandall P.G. , O'Bryan C.A. , Griffis C.L. , Martin E.M.
Published: April 2007

ABSTRACT:  Americans consume almost 40 kg per capita of chicken each year. Increasing consumption of chicken surpassed pork in 1982 and beef in 1992. The objectives of this study were to examine the effectiveness of a novel, 2‐step cooking method of grilling, slicing, vacuum packaging, and hot water pasteurization to inhibit the growth of Listeria monocytogenes in chicken breast meat. Because this study required the use of pilot plant scale pasteurization equipment, Listeria innocua M1, a nonpathogen with slightly greater heat resistance than L. monocytogenes, was used as a surrogate. We first examined the lethal effects of grilling on a boneless skinless chicken breast to mimic cross‐contaminated, surface‐inoculated Listeria. Searing produced a mean reduction of 2.5 log CFU/g of Listeria and a moisture loss of only 7% (w/w). A 2nd experiment studied the lethal effect of pasteurization of the sliced seared chicken breast. L. innocua M1 inoculated between the slices mimiced contamination in deep muscle. Pasteurization in a 71 °C bath (final internal temperature of 66 °C) gave an additional 2.3 log CFU/g reduction. L. innocua M1 did not show significant regrowth during a wk of refrigerated storage. The combined 2‐step cooking method of searing and pasteurization gave a combined 4.8 log reduction in LI M1. In parallel tests a non‐Listeria indicator, Corynebacterium glutamicum, inoculated between sliced, seared chicken, showed a 3 log reduction after pasteurization for 10 min in a 71 °C bath compared to 2.3 log reduction of Listeria. Corynebacterium regrowth occurred much faster than did L. innocua M1.