bluuebunny/crossref_metadata_2025 huggingface dataset:
A case study of a TFE explosion in a PTFE manufacturing facility
Authors: Reza Ali , Christiansen Erik
Published: November 2006

A 1999 explosion in the purification area of a fluorinated polymer manufacturing plant in the United States caused fatal injuries to three employees. Another employee was severely injured. The affected plant personnel were attempting to locate a suspected polymer plug in lines containing tetrafluoroethylene (TFE) monomer upstream of the polymerization plant. In an attempt to dislodge a possible plug in an elbow leading off a pressure vessel, one of the employees rapidly actuated a manually operated ball valve. High‐pressure TFE upstream of the valve rushed into the downstream piping, which likely contained air at subatmospheric pressure. Adiabatic compression against a blind flange created temperatures sufficient to ignite a TFE/air mixture. The initial deflagration provided ample energy for a self‐sustaining decomposition reaction to propagate within the TFE line into the upstream pressure vessel. Liquid TFE had been collecting in the pressure vessel as the result of a deliberate increase in the flow of cooling brine associated with a separate process. This allowed the decomposition to continue, causing a rapid increase in pressure inside the vessel, sufficient for the bolts on the upper flange to fail. The four employees were exposed to burning TFE sprayed from the pressure vessel and were also injured by shrapnel created by the explosion.

Exponent Failure Analysis Associates was retained to conduct an engineering investigation of the incident, including a technical analysis of the conditions leading to the explosion. We also reviewed the HAZOP performed by the employer that failed to note critical parameters that contributed to the incident. This article discusses findings from the investigation as well as lessons on handling TFE that can be learned from the incident. © 2006 American Institute of Chemical Engineers Process Saf Prog, 2007
A model for estimating the probability of missile impact: Missiles originating from bursting horizontal cylindrical vessels
Authors: Pula Ravi , Khan Faisal I. , Veitch Brian , Amyotte Paul R.
Published: November 2006

Past explosion events in process facilities have centered attention on the fact that missiles generated as the result of vessel fragmentation pose significant risk to personnel and process equipment and can trigger knock‐on or domino effects in industrial accidents. To promote the design of inherently safer facilities—and to enable more effective mitigation and control measures with respect to missile risks—it is necessary to perform missile risk analysis studies at the early design phase. To aid in such an analysis and to predict domino scenarios, it is essential to have models that can quantify (1) the probability of a missile impact on a target and (2) the consequences of the probable impact.

In the present work, we propose a model to quantify the probability of missiles that originate from bursting horizontal cylinders, having an impact on spherical target vessels located in a process area. Although previous investigations on the quantification of missile impact probability were based on a single‐scenario approach, the current model is based on two credible scenarios. The model is built on the concept of a vulnerable area (VA), defined as the probable impact zone sketched around the target object. The concept of an effective range interval (ERI) was adopted and was extended by introducing an effective trajectory interval (ETI) and effective orientation interval (EOI). The uncertainties in the model parameters were addressed by means of Monte Carlo sampling approach. A case study is used to evaluate the performance of the proposed model. The case study uses a grid‐based approach (GBA) to provide interactive contour plotting of the missile impact probabilities over a defined process area. © 2006 American Institute of Chemical Engineers Process Saf Prog, 2007
Lack of cross‐resistance to Mtx1 from Bacillus sphaericus in B. sphaericus‐resistant Culex quinquefasciatus (Diptera: Culicidae)
Authors: Wei Suzhen , Cai Quanxin , Cai Yajun , Yuan Zhiming
Published: November 2006

The toxicities of Mtx1 toxin against dipteran and lepidopteran species have been evaluated in this study. It was shown that Mtx1 has little or no toxicity to the tested lepidopteran species, but has moderate‐level toxicity to Aedes albopictus Skuse (Diptera: Culicidae) and high‐level toxicity to both susceptible and binary toxin‐resistant Culex quinquefasciatus Say (Diptera: Culicidae). The LC50 values of Mtx1 against a susceptible C. quinquefasciatus colony SLCq and two resistant colonies RLCq1/C3‐41 and RLCq2/IAB59 selected in the laboratory with Bacillus sphaericus (Mayer & Neide) strains C3‐41 and IAB59 respectively were 0.508, 0.854 and 0.675 mg L−1 respectively. The data indicate that Mtx1 has a different mode of action from the binary toxin, and that it could be an alternative toxin to delay or overcome resistance development to binary toxin in C. quinquefasciatus. Copyright © 2007 Society of Chemical Industry
Influence of Sn concentration on the physical properties of CdO:Sn thin films deposited by spray pyrolysis
Authors: Vigil‐Galán O. , Sánchez‐González Y. , Arias‐Carbajal A. , Contreras‐Puente G. , Tufiño‐Velázquez M. , Ruiz C. M.
Published: November 2006

Sn doped cadmium oxide thin films were prepared on glass substrates by the spray pyrolysis (SP) method from a cadmium acetate aqueous solution. The Sn (IV) concentration in the solution was varied up to 2 wt%, keeping constant the other growth parameters. The structural, electrical and optical properties of the films were studied as a function of Sn concentration. The best results were obtained for CdO films doped with 1% Sn nominal concentration. The properties of these films are influenced by the air annealing performed at 450 °C for 30–120 min. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fast coloration in sputtered gasochromic tungsten oxide films
Authors: Shanak H. , Schmitt H.
Published: November 2006

Thin films of WO3 were deposited with different thickness in a mixed atmosphere of O2 and Ar gas from a high purity target of 99.99% tungsten using reactive DC‐sputtering technique. Same amount of the Pt catalyst was sputtered from a high purity target of 99.99% platinum in Ar atmosphere onto the top of the WO3 films with different thickness. Coloration takes place in hydrogen and bleaching in oxygen gases. During the coloration/bleaching process several optical parameters were determined. The velocity of coloration process increases with increasing the thickness of the films. The change of the transmission in the visible and near infrared regions was measured during coloration and bleaching process. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of TSC measurements performed on PbI2 samples prepared in different ways
Authors: Ponpon J. P.
Published: November 2006

The role of preparation and growth on the presence of energy levels in the band gap of lead iodide crystallized material has been investigated by means of thermally stimulated current measurements. The most significant difference is concerned with the defect introduced by the lead vacancy: the associated energy levels are always present when the material has experienced a molten state at any step of its preparation. Conversely, it does not appear or at a very low concentration in samples fabricated at low temperature from chemically synthesized powder. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetotransport characterization of AlGaN/GaN interfaces
Authors: Tauk R. , Tiberj A. , Lorenzini P. , Bougrioua Z. , Azize M. , Sakowicz M. , Karpierz K. , Knap W.
Published: November 2006

Magnetotransport studies of high quality AlGaN/GaN heterojunctions are reported. The transport and quantum lifetimes were respectively deduced from low temperature mobility and Shubnikov de Haas measurements as a function of carrier density in metal organic vapor phase epitaxy grown AlGaN/GaN/sapphire heterostructures. It is found that contrary to theoretical predictions both quantum and transport lifetimes have the same bell shape behavior versus carrier density. We determined experimental ratio of quantum to transport lifetime varying from 9 to 16 for carrier densities in 1–9 × 1012 cm–2 range. We show that the quantum lifetime is very sensitive to interface scattering at high carrier density. Therefore, our work shows how Shubnikov de Haas experiments can be used to characterize the quality of AlGaN/GaN interfaces used in modern light emitting devices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of Synacthen in human plasma using immunoaffinity purification and liquid chromatography/tandem mass spectrometry
Authors: Thevis Mario , Bredehöft Michael , Geyer Hans , Kamber Matthias , Delahaut Philippe , Schänzer Wilhelm
Published: November 2006

Synacthen is a synthetic analogue to human adrenocorticotropin, which plays an important physiological role by stimulating production of cortisol. In sports, corticosteroids as well as releasing factors (corticotropins) are prohibited according to the regulations of the World Anti‐Doping Agency, and the misuse of Synacthen has been reported several times. Hence, an assay enabling the detection of Synacthen in doping control samples has been developed using immunoaffinity chromatographic isolation of Synacthen from human plasma combined with a concentration of collected fractions using solid‐phase extraction. Unambiguous determination of the target analyte was accomplished using microbore liquid chromatography/electrospray ionization tandem mass spectrometry. Diagnostic product ions such as m/z 223 were characterized using high‐resolution/high‐accuracy Orbitrap mass spectrometry and employed for triple quadrupole MS/MS analysis. The established assay requiring 2 mL of plasma allowed a lower limit of detection (LLOD) at 100 fmol/mL, a recovery of 97% and a precision at the LLOD <20%. Authentic plasma samples obtained from a patient undergoing a standard short Synacthen test were used to prove the applicability of the developed procedure. Copyright © 2006 John Wiley & Sons, Ltd.
Decentralized adaptive scheduling using consensus variables
Authors: Moore Kevin L. , Lucarelli Dennis
Published: November 2006

In this paper we present a new approach to decentralized adaptive scheduling, using recent results on the control of consensus variables in graphs with nearest‐neighbour communication topologies. First, existing results for single consensus variables are extended to include the cases of forced consensus, when one of the negotiating agents is driven by a setpoint, and of constrained consensus, where multiple consensus variables are required to be separated by a fixed amount. Next, we consider a class of adaptive scheduling problems, whereby a set of decentralized coordinators should cooperate to adapt shared schedule times in response to disturbances or changes in the system. Our approach is to choose task timings to be the consensus variables in the system. The utility of these ideas is illustrated using the example of a synchronized strike mission. Copyright © 2006 John Wiley & Sons, Ltd.
Lur'e Lyapunov functions and absolute stability criteria for Lur'e systems with multiple nonlinearities
Authors: Yang Chunyu , Zhang Qingling , Zhou Linna
Published: November 2006

In this paper, the absolute stability problem of Lur'e systems with multiple nonlinearities is investigated. Popov‐type absolute stability criteria are surveyed and classified by distinguishing the Lur'e Lyapunov function upon which the criteria are based. A modified Lur'e Lyapunov function is presented. Some necessary and sufficient conditions for the existence of the Lyapynov function to guarantee the absolute stability of Lur'e systems are derived. By these conditions, LMI‐based stability criteria are presented. The obtained criteria are expected to be less conservative than the existing ones. Finally, numerical examples are given to illustrate the advantages and effectiveness of our results. Copyright © 2006 John Wiley & Sons, Ltd.
Hydrogen 3D‐distribution and the kinetics in a Ti/H system studied by micro‐ERDA, NRA and XRD
Authors: Wang T. S. , Grambole D. , Herrmann F. , Peng H. B. , Wang S. W.
Published: November 2006

The micro kinetics of titanium hydrogenation is studied by measuring the three‐dimensional hydrogen distribution in titanium subsurfaces by elastic recoil detection analysis with a heavy ion micro‐beam, 1H(15N, αγ) 12C resonant nuclear reaction analysis and X‐ray diffraction. The hydrogen rich layers in the titanium subsurface region are formed by mechanical polishing and hydrogen ion implantation. An inhomogeneous hydrogen distribution is found in the subsurface region. The inhomogeneity varies with hydrogen concentration and depth. The hydrogen loaded by surface polishing distributes roughly homogeneously in the near surface with a high concentration up by 60 at.%, whereas the implanted hydrogen distributes inhomogeneously inside the sample with a lower concentration. Nevertheless, the inhomogeneity changes with the implantation fluence; the higher the fluence, the better the homogeneity. This phenomenon is considered to be affected by complications such as the hydrogen ingression process, hydrogen states, titanium grain size and orientation, etc. Copyright © 2006 John Wiley & Sons, Ltd.
Occurrence and functions of free D‐aspartate and its metabolizing enzymes
Authors: Yamada Ryo‐Hei , Kera Yoshio , Takahashi Shouji
Published: November 2006

D‐Aspartate is one of a few D‐amino acids that attracted attention at an early date, since it was detected in various tissues of mammals as a protein component. The occurrence of free D‐aspartate in nature was recognized a little later, and raised questions about its physiological functions and metabolism. This amino acid has been gradually accepted, based on various experimental observations, to be a physiological substrate of D‐aspartate oxidase, whose role had been considered enigmatic since its early discovery in the 1940s. Mammalian enzymes that serve to liberate D‐aspartyl residue in proteins have been identified. One enzyme hydrolyzes peptide bond at the amino side of D‐aspartyl residue in a dipeptide and another enzyme hydrolyzes that at the carbonyl side of the residue in proteins. The first pyridoxal 5′‐phosphate‐dependent aspartate racemase has been purified and cloned from a bivalve species. The enzyme supports the high contents of D‐aspartate comparable to those of L‐aspartate in the bivalve, and the enantiomers are consumed when hypoxia is imposed on the bivalve. In some yeast species, assimilation of D‐aspartate has been found to depend on inducible D‐aspartate oxidase, which also serves to detoxify acidic D‐amino acids. (c) 2006 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 6: 259–266; 2006: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20089
Is D‐dimer a Predictor of Strangulated Intestinal Hernia?
Authors: Icoz Gokhan , Makay Ozer , Sozbilen Murat , Gurcu Baris , Caliskan Cemil , Firat Ozgur , Kurt Zahide , Ersin Sinan
Published: November 2006

Background

The goal of this study was to assess the relevance of serum D‐dimer measurement as a possible reliable marker for the diagnosis of strangulated intestinal hernia.

Methods

Consecutive patients admitted with nontraumatic acute abdominal gastrointestinal disorders were recruited prospectively in a tertiary referral hospital. The study was conducted in 159 patients between August 2002 and April 2004. D‐dimer, lactate dehydrogenase, serum amylase, and international normalized ratio (INR) levels were tested in the emergency room prior to surgical intervention. For each patient, 15 variables, including D‐dimer, were available for analysis.

Results

Thirty‐three (20.7%) of the 159 patients had intestinal ischemia, and 28 (85%) of these 33 patients had D‐dimer level > 300 ng/ml. Plasma levels of D‐dimer in patients with intestinal ischemia were significantly higher than in patients without ischemia (P < 0.05). There were 29 (18.2%) patients in the hernia group with incarceration (n = 22) or strangulation requiring resection (n = 7). D‐dimer levels in patients requiring intestinal resection were insignificantly higher than in patients without resection (P > 0.05). Six (85%) of the 7 hernia patients requiring resection had D‐dimer levels > 360 ng/ml. The D‐dimer variable correlated best with the leukocyte count in patients with hernia requiring resection. Levels of lactate dehydrogenase, serum amylase, and INR did not show any correlation with D‐dimer levels.

Conclusions

To help predict ischemic events, the increasing use of the D‐dimer assay in clinical practice could be extended to patients presenting with intestinal emergencies. An elevated D‐dimer level on admission had a high sensitivity for identifying patients with intestinal ischemia, although it had a low specificity. Whether it is predictive or preventive for resection in strangulated intestinal hernia patients still remains a question.
Survival of Early Gastric Cancer in a Specialized European Center. Which Lymphadenectomy Is Necessary?
Authors: Degiuli Maurizio , Calvo Fabio
Published: November 2006

Purpose

A clinicopathological study of early gastric cancer has been carried out in a single experienced surgical unit to identify prognostic indicators for survival and factors related to lymph nodes metastasis and document a survival benefit of D2 gastrectomy.

Methods

A retrospective review of our database from January 1990 to December 2004 revealed 189 patients with early gastric cancer undergoing surgical resection with either D1 or D2 lymph node dissection. Clinicopathological factors analyzed included Lauren’s histological type, histological differentiation, size, mucosal versus submucosal invasion, venous invasion, number of lymph node involved, and extent of nodal dissection performed. Factors related to increased risk of nodal metastases and predicting 5‐ and 10‐year disease‐specific survival were evaluated by univariate and multivariate analysis.

Results

Median follow‐up time was 77 months. Lymph node involvement was documented in 21.1% of patients. A D2 gastrectomy was performed in 56% of patients. The cumulative 10‐year survival rate was 92.5%; it was strictly related to nodal metastases (p =. 0014). Poor differentiation, size larger than 2 cm, and submucosal depth of invasion were related to increased risk of nodal metastases but not to decreased survival. Overall, 10‐year survival after D2 gastrectomy was higher than after D1 gastrectomy (95 versus 87.5%), but this difference was not statistically significant (p =. 80). No survival benefit was documented for D2 gastrectomy in subsets of patients with increased risk of nodal metastasis.

Conclusion

In this retrospective analysis a survival benefit of D2 gastrectomy was not documented either in the overall population or in subset analyses of patients with increased risk of nodal metastasis.
Body size and resource partitioning in ladybirds
Authors: Dixon A. F. G.
Published: November 2006

Aphidophagous insects all exploit aphids as food, but there appears to be no association between the size of the aphidophagous predator and that of the species or the age structure of the aphid colonies they exploit. Aphid colonies generally increase, peak and decline in abundance, and are exploited by a sequence of predators, which is consistent from year to year. The objective of this study was to determine the rules underlying this temporal pattern. For example, in the field, aphid colonies are often first attacked by a small and then a larger species of ladybird. Theory based on the geometry and physiology of ladybirds predicts that the quantity of food required for oviposition and the area searched per unit time should scale with body weight, with exponents of 1 and 0.66, respectively. An analysis of empirical data supports these predictions. Thus, in relative terms a 35 mg ladybird requires 1.5 times more aphids per unit area for oviposition than a 10 mg ladybird. That is, the temporal pattern in oviposition is possibly mainly determined by geometrical and physiological constraints associated with body size, with small species of ladybird able to lay eggs at lower aphid population densities than large species. Cannibalism is thought to be the mechanism by which these predators are able to coexist.
A Survey of Patients’ Experiences with the Cancer Genetic Counseling Process: Recommendations for Cancer Genetics Programs
Authors: Kausmeyer Dana T. , Lengerich Eugene J. , Kluhsman Brenda C. , Morrone Dorothy , Harper Gregory R. , Baker Maria J.
Published: November 2006

In order to promote ongoing quality improvement of not only the Penn State Cancer Genetics Program, but also other cancer risk assessment programs throughout the country, we developed, piloted and conducted a survey to explore patient expectations, experiences, and satisfaction with the cancer genetic counseling process. The comprehensive survey was mailed to 340 eligible patients, 156 (45.9%) of whom returned the completed survey within the allotted time. Responses to closed‐ended questions were tallied and open‐ended questions were content analyzed. Major findings show that: (1) Patients were seeking cancer‐related information and support throughout the cancer risk assessment process and were interested in participating in available research studies; (2) The setting in which patients are seen for cancer risk assessment may pose potential emotional ramifications; (3) Misperceptions regarding insurance discrimination and lack of insurance coverage persist; (4) Patients view the genetic counselor as responsible for updating them about new discoveries. Specific recommendations for cancer genetics programs are included.
Symmetries, Group Actions, and Entanglement
Authors: Grabowski Janusz , Kuś Marek , Marmo Giuseppe
Published: November 2006

We address several problems concerning the geometry of the space of Hermitian operators on a finite-dimensional Hilbert space, in particular the geometry of the space of density states and canonical group actions on it. For quantum composite systems we discuss and give examples of entanglement measures.
Exploring Representation Theory of Unitary Groups via Linear Optical Passive Devices
Authors: Aniello P. , Lupo C. , Napolitano M.
Published: November 2006

In this paper, we investigate some mathematical structures underlying the physics of linear optical passive (LOP) devices. We show, in particular, that with the class of LOP transformations on N optical modes one can associate a unitary representation of U (N) in the N-mode Fock space, representation which can be decomposed into irreducible sub-representations living in the subspaces characterized by a fixed number of photons. These (sub-)representations can be classified using the theory of representations of semi-simple Lie algebras. The remarkable case where N = 3 is studied in detail.
Entanglement, Decoherence and Correlations in a Strongly Driven Jaynes-Cummings System
Authors: Casagrande F. , Lulli A.
Published: November 2006

We consider the resonant interaction of a cavity mode with a two-level atom that is driven by a coherent field while it crosses the cavity. Starting from the cavity field in a coherent state, we show that the state of the system can reach the maximum entanglement after a unitary evolution for long enough interaction times. Also we illustrate how the generation of cavity field superposition states can allow, in the open system dynamics, the observation of their decoherence in atomic correlation measurements, for any initial cavity field state, and even under the combined effects of dissipation, thermal noise, and atomic pumping.
Component Models for Fuzzy Data
Authors: Coppi Renato , Giordani Paolo , D’Urso Pierpaolo
Published: November 2006

The fuzzy perspective in statistical analysis is first illustrated with reference to the “Informational Paradigm" allowing us to deal with different types of uncertainties related to the various informational ingredients (data, model, assumptions). The fuzzy empirical data are then introduced, referring to J LR fuzzy variables as observed on I observation units. Each observation is characterized by its center and its left and right spreads (LR1 fuzzy number) or by its left and right “centers" and its left and right spreads (LR2 fuzzy number). Two types of component models for LR1 and LR2 fuzzy data are proposed. The estimation of the parameters of these models is based on a Least Squares approach, exploiting an appropriately introduced distance measure for fuzzy data. A simulation study is carried out in order to assess the efficacy of the suggested models as compared with traditional Principal Component Analysis on the centers and with existing methods for fuzzy and interval valued data. An application to real fuzzy data is finally performed.
Effects of dietary lipids on daunomycin‐induced nephropathy in mice: Comparison between cod liver oil and soybean oil
Authors: Ohtake Takayasu , Kimura Masato , Takemura Hitomi , Hishida Akira
Published: November 2006

Although it is well known that dietary lipids affect the course of glomerulonephritis in rats and humans, the precise mechanisms involved have not been fully elucidated. The aim of this study was to investigate the effects of different types of dietary lipids (fish oil and vegetable oil) on daunomycin (DM)‐induced nephropathy in mice fed on soybean oil (SO) or cod liver oil (CLO). Urinary protein excretion, serum albumin, creatinine, total cholesterol, and TG were measured, and glomerular histological changes were evaluated. Antioxidant enzymes were also measured, along with the levels of lipid peroxide, GSH, thromboxane (Tx) B2′ and 6‐keto prostaglandin F1α in renal cortical tissue. Dietary CLO significantly reduced urinary albumin excretion and ameliorated the histological changes induced by DM. The increase of tissue lipid peroxide levels seen in SO‐fed mice was suppressed in CLO‐fed mice, whereas CLO‐fed mice showed higher GSH levels than SO‐fed mice throughout the experiment. In addition, renal tissue GSH peroxidase activity was significantly higher at 72 h after DM injection in CLO‐DM mice than in SO‐DM mice. Both renal cortical TxB2 and 6‐keto PGF1α levels were significantly lower in CLO‐DM mice than in SO‐DM mice. These results suggest that inhibition of oxidative damage by dietary CLO played an important role in the prevention of DM nephropathy in this mouse model. The effect of CLO was closely associated with the inhibition of Tx synthesis.
Long‐term n‐3 FA deficiency modifies peroxisome proliferator‐activated receptor β mRNA abundance in rat ocular tissues
Authors: Rojas Cecilia V. , Greiner Rebecca S. , Fuenzalida Lidia C. , Martínez Jessica I. , Salem Norman , Uauy Ricardo
Published: November 2006

Peroxisomal proliferator‐activated receptors (PPAR) are a FA‐response system involved in diverse cellular responses. FA regulate PPAR activity and modulate PPAR mRNA abundance. Increasing evidence indicates that PUFA are required for optimal neuronal development and function. To gain insight into the mechanism for nutrition‐induced impairment of neuronal development and function we investigated the effect of chronic n‐3 FA deficiency on PPAR mRNA levels in rat brain and ocular tissues. Rats were fed for three generations a diet designed to reduce DHA levels in tissues, and the abundance of PPARα and PPARβ transcripts was measured by hybridization with specific probes. Chronic consumption of the α‐linolenic acid (LNA)‐insufficient diet caused a remarkable modification in DHA content in membrane phospholipids. The results reported here indicate that PPARα mRNA levels did not exhibit significant variation in ocular, hepatic, or nervous tissues from rats fed the experimental diet. In contrast, PPARβ mRNA normalized to β‐actin mRNA was 21% higher in ocular tissue from F3 generation rats consuming the LNA‐deficient diet but was independent of diet in hepatic and nervous tissues. The absolute abundance of PPARβ transcripts showed a 17% increase in ocular tissue from rats consuming the LNA‐deficient diet (F3 generation). The biological significance of the reported changes in PPARβ mRNA in ocular tissue remains to be determined.
Dietary cholesterol modulates Δ6 and Δ9 desaturase mRNAs and enzymatic activity in rats fed a low‐EFA diet
Authors: Brenner Rodolfo R. , Bernasconi Ana M. , González María S. , Rimoldi Omar J.
Published: November 2006

The effects of a 1% addition of cholesterol to a diet low in EFA on FA desaturases were examined. The administration of cholesterol markedly increased the esterified cholesterol content in microsomes and total liver lipids from the first day, whereas the proportion of free cholesterol remained unaltered throughout the treatment. An excellent homeostasis in the free cholesterol content was apparently evoked by the acyl‐CoA cholesterol acyltransferase. The cholesterol esters were mainly oleate, palmitate, and stearate, and the addition of cholesterol increased the relative proportions of cholesterol palmitoleate and oleate. The addition of cholesterol to a low‐EFA diet induced, as in animals fed a high‐FFA diet, a marked increase in liver stearoyl‐CoA desaturase‐1 mRNA and enzyme activity. This increased activity apparently evoked a similar enhancement of palmitoleic and oleic acids in total and microsomal liver lipids. The cholesterol‐rich diet depressed the liver Δ6 and Δ5 desaturase activity. However, the abundance of Δ6 desaturase mRNA was not modified throughout the treatment. This indicates that the depressive effect is evoked at a step beyond that controlled by the mRNA level. The depression of both enzymatic activities was consistent with the decrease in the percentages of arachidonic acid and DHA in total and microsomal liver lipids. Taken together, these results indicate that through its modulating effect on the desaturases, dietary cholesterol may lead an animal or humaan fed low‐EFA diet to a true deficiency by the decreased synthesis of the highly polyunsaturated acids derived from linoleic and α‐linolenic acids.
Increased cardiomyocyte apoptosis following ischemia and reperfusion in diet‐induced hypercholesterolemia: Relation to Bcl‐2 and bax proteins and caspase‐3 activity
Authors: Wang Tzung‐Dau , Chen Wen‐Jone , Su Sophia Seh‐Yi , Lo Shyh‐Chyi , Lin Wan‐Wan , Lee Yuan‐Teh
Published: November 2006

It has been reported that apoptosis is a significant contributor to myocardial cell death as a result of reperfusion injury. However, whether the extent of cardiomyocyte apoptosis following ischemia and reperfusion varies in different pathophysiological backgrounds is still uncertain. In this study, we examined whether hypercholesterolemia increases the extent of myocardial reperfusion injury by aggravating cardiomyocyte apoptosis and the effects of hypercholesterolemia on the expression of Bcl‐2 and Bax proteins and the activation of caspase‐3. Twenty‐eight male New Zealand white rabbits were fed standard chow (control, n=14) or chow supplemented with 1% cholesterol (hypercholesterolemic, n=14) for 8 wk. Anesthetized rabbits were then subjected to 30 min of left circumflex artery occlusion followed by 4 h of reperfusion. Apoptosis was identified as “DNA ladders” by gel electrophoresis and confirmed histologically using the terminal deoxynucleotidyl transferase‐mediated dUTP‐biotin nick end labeling (TUNEL) assay. The infarct size (% of risk region) was significantly greater in hypercholesterolemic rabbits than in controls (39±6 vs. 23±2%, P=0.02). Very few TUNEL‐positive cardiomyocytes could be identified in the nonischemic regions in both groups, consistent with an absence of DNA laddering. In contrast, TUNEL‐positive cardiomyocytes were significantly displayed in the ischemic, nonnecrotic myocardium, and DNA ladder occurred in all animals. The percentage of TUNEL‐positive cardiomyocytes in the ischemic nonnecrotic myocardium was significantly higher in hypercholesterolemic rabbits compared with controls (40±5 vs. 17±1%, P<0.001). Western blot analysis showed that, in the nonischemic myocardium, hypercholesterolemic rabbits exhibited an approximately 50% increase in the expression of Bcl‐2 (P<0.05), but not Bax, than control rabbit. However, compared with controls, hypercholesterolemic rabbits exhibited a more pronounced decrease in the expression of Bcl‐2 (42±4 vs. 26±2%, P<0.01) and a similar extent of increase in the expression of Bax in the ischemic myocardium. Furthermore, hypercholesterolemic rabbits were associated with a markedly increased activation of caspase‐3 within the ischemic myocardium compared to control rabbits. This study demonstrates that although hypercholesterolemia is associated with an increased myocardial Bcl‐2/Bax ratio at baseline, it still significantly exacerbates cardiac reperfusion injury, not only by increasing the infarct size but also by increasing the extent of cardiomyocyte apoptosis.
Effect of SMP‐500, a novel ACAT inhibitor, on hepatic cholesterol disposition in rats
Authors: Ioriya Katsuhisa , Nishimura Takeshi , Ohashi Naohito
Published: November 2006

The effects of SMP‐500, a novel ACAT inhibitor, on serum lipid levels, hepatic lipid secretion rate, and hepatic lipid disposition in rats were studied to clarify its lipid‐lowering action. SMP‐500 reduced the serum cholesterol level in a dose‐dependent manner in rats fed a hypercholesterolemic diet. SMP‐500 also reduced hepatic free cholesterol content in addition to hepatic total and esterified cholesterol contents. Biliary concentrations of cholesterol and bile acid were increased by SMP‐500; however, the bile flow and lithogenic index were not affected. SMP‐500 increased cholesterol 7α‐hydroxylase mRNA level. Therefore, it is suggested that the increase in concentrations of cholesterol and bile acid in bile is due to both the increase of bile acid production through the increase of cholesterol 7α‐hydroxylase and the decrease of hepatic free cholesterol content. An inhibitory effect of SMP‐500 both on the cholesterol secretion and on the TG secretion from liver was observed. SMP‐500 reduced the serum TG level in sucrose‐fed rats. From these results, one may hypothesize that the suppression of hepatic VLDL secretion probably plays an important role on both cholesterol‐ and TG‐lowering effects of SMP‐500.
FA composition of heart and skeletal muscle during embryonic development of the king penguin
Authors: Decrock Frederic , Groscolas René , Speake Brian K.
Published: November 2006

Since the yolk lipids of the king penguin (Aptenodytes patagonicus) naturally contain the highest concentrations of DHA and FPA yet reported for the eggs of any avian species, the effects of this (n‐3)‐rich yolk on the FA profiles of the embryonic heart and skeletal muscle were investigated. The concentrations (mg/g wet tissue) of phospholipid (PL) in the developing heart and leg muscle of the penguin doubled between days 27 and 55 from the beginning of egg incubation (i.e., from the halfway stage of embryonic development of 2 d posthatch), whereas no net increase occurred in pectoral muscle. During this period, the concentration of TAG in heart decreased by half but increased two‐ and sixfold in leg and pectoral muscle, respectively. The most notable change in cholesteryl ester concentration occurred in pectoral muscle, increasing ninefold between days 27 and 55. Arachidonic acid (ARA) was the major polyunsaturate in PL of the penguin's heart, where it formed about 20% (w/w) of FA at day 55. At the equivalent developmental stage, the heart PL of the chicken contained a 1.3‐fold greater proportion of ARA, contained a fifth less DHA, and was almost devoid of EPA, whereas the latter FA was a significant component (7% of FA) of penguin heart PL. Similarly, in PL of leg and pectoral muscle, the chicken displayed about 1.4‐fold more ARA, up to 50% less DHA, and far less EPA in comparison with the penguin. Thus, although ARA‐rich PL profiles are achieved in the heart and muscle of the penguin embryo, these profiles are significantly affected by the high n‐3 content of the yolk.
Biosynthesis of new divinyl ether oxylipins in Ranunculus plants
Authors: Hamberg Mats
Published: November 2006

[1‐14C]Linolenic acid was incubated with homogenates of leaves from the aquatic plants Ranunculus lingua (greater spearwort) or R. peltatus (pond water‐crowfoot). Analysis by reversed‐phase high‐performance liquid radiochromatography demonstrated the formation of a new divinyl ether FA, i.e., 12‐[1′(E), 3′(Z)‐hexadienyloxy]‐9(Z), 11(Z)‐dodecadienoic acid [11(Z)‐etherolenic acid] as well as a smaller proportion of ω5(Z)‐etherolenic acid previously identified in terrestrial Ranunculus plants. The same divinyl ethers were formed upon incubation of 13(S)‐hydroperoxy‐9(Z), 11(E), 15(Z)‐octadecatrienoic acid, a lipoxygenase metabolite of linolenic acid, whereas the isomeric hydroperoxide, 9(S)‐hydroperoxy‐10(E), 12(Z), 15(Z)‐octadecatrienoic acid, was not converted into divinyl ethers in R. lingua or R. peltatus. Incubation of [1‐14C]linoleic acid or 13(S)‐hydroperoxy‐9(Z), 11(E)‐octadecadienoic acid produced the divinyl ether 12‐[1′(E)‐hexenyloxy]‐9(Z), 11(Z)‐dodecadienoic acid [11(Z)‐etheroleic acid] and a smaller amount of ω5(Z)‐etheroleic acid. The experiments demonstrated the existence in R. lingua and R. peltatus of a divinyl ether synthase distinct from those previously encountered in higher plants and algae.
General characteristics of Pinus spp. Seed fatty acid compositions, and importance of Δ5‐olefinic acids in the taxonomy and phylogeny of the genus
Authors: Wolff Robert L. , Pédrono Frédérique , Pasquier Elodie , Marpeau Anne M.
Published: November 2006

The Δ5‐unsaturated polymethylene‐interrupted fatty acid (Δ5‐UPIFA) contents and profiles of gymnosperm seeds are useful chemometric data for the taxonomy and phylogeny of that division, and these acids may also have some biomedical or nutritional applications. We recapitulate here all data available on pine (Pinus; the largest genus in the family Pinaceae) seed fatty acid (SFA) compositions, including 28 unpublished compositions. This overview encompasses 76 species, subspecies, and varieties, which is approximately one‐half of all extant pines officially recognized at these taxon levels. Qualitatively, the SFA from all pine species analyzed so far are identical. The genus Pinus is coherently united—but this qualitative feature can be extended to the whole family Pinaceae—by the presence of Δ5‐UPIFA with C18 [taxoleic (5,9–18∶2) and pinolenic (5,9,12–18∶3) acids] and C20 chains [5,11–20∶2, and sciadonic (5,11,14–20∶3) acids]. Not a single pine species was found so far with any of these acids missing. Linoleic acid is almost always, except in a few cases, the prominent SFA, in the range 40–60% of total fatty acids. The second habitual SFA is oleic acid, from 12 to 30%. Exceptions, however, occur, particularly in the Cembroides subsection, where oleic acid reaches ca. 45%, a value higher than that of linoleic acid. α‐Linolenic acid, on the other hand, is a minor constituent of pine SFA, almost always less than 1%, but that would reach 2.7% in one species (P. merkusii). The sum of saturated acids [16∶0 (major) and 18∶0 (minor) acids principally] is most often less than 10% of total SFA, and anteiso‐17∶0 acid is present in all species in amounts up to 0.3%. Regarding C18 Δ5‐UPIFA, taxoleic acid reaches a maximum of 4.5% of total SFA, whereas pinolenic acid varies from 0.1 to 25.3%. The very minor coniferonic (5,9,12,15–18∶4) acid is less than 0.2% in all species. The C20 elongation product of pinolenic acid, bishomo‐pinolenic (7,11,14–20∶3) acid, is a frequent though minor SFA constituent (maximum, 0.7%). When considering C20 Δ5‐UPIFA, a difference is noted between the subgenera Strobus and Pinus. In the former subgenus, 5,11–20∶2 and sciadonic acids are ≤0.3 and ≤1.9%, respectively, whereas in the latter subgenus, they are most often ≥0.3 and ≥2.0%, respectively. The highest values for 5,11–20∶2 and sciadonic acids are 0.5% (many species) and 7.0% (P. pinaster). The 5,11,14,17–20∶4 (juniperonic) acid is present occasionally in trace amounts. The highest level of total Δ5‐UPIFA is 30–31% (P. sylvestris), and the lowest level is 0.6% (P. monophylla). Uniting as well as discriminating features that may complement the knowledge about the taxonomy and phylogeny of pines are emphasized.
The biosynthesis of oxylipins of linoleic and arachidonic acids by the sewage fungus Leptomitus lacteus, including the identification of 8R‐hydroxy‐9Z,12Z‐octadecadienoic acid
Authors: Fox Simon R. , Akpinar Arzu , Prabhune Asmita A. , Friend John , Ratledge Colin
Published: November 2006

When the sewage fungus Leptomitus lacteus was grown in liquid culture aerobically and then transferred to medium containing long‐chain fatty acids, it produced a number of oxygenated fatty acids. From linoleic acid (18∶2n−6), the major metabolite produced was R‐8‐hydroxy‐9Z,12Z‐octadecadienoic acid (8R‐HODE), with additional quantities of 8,11‐di‐HODE, 11,16‐di‐HODE, and 11,17‐di‐HODE. Other fatty acid derivatives identified included 7‐HODE, 10‐HODE, and 13‐hydroxy‐octadecamonoenoic acid. Arachidonic acid (20∶4n−6) was metabolized primarily to 18‐ and and 19‐hydroxy‐eicosatetraenoic acids (18‐ and 19‐HETE) also as R enantiomers, along with smaller quantities of 17‐HETE, 9‐HETE, 14,15‐dihydroxyeicosatrienoic acid and 11,12,19‐trihydroxy‐eicosatrienoic acid. The oxygenated products of long‐chain fatty acids, in particular the biosynthesis of 8R‐HODE, a compound classified as a precocious sporulation inducer, were similar to those produced by an unrelated fungal species in the Ascomycota, the take‐all fungus Gaeumannomyces graminis. As in G. graminis, the biotransformation of linoleate to 8R‐HODE was not significantly inhibited by exposure of the organism to CO. This indicated that the enzyme responsible for 8R‐HODE biosynthesis in Leptomitus could be similar to that of G. graminis; yet we did not detect 7,8‐di‐HODE as a product of 18∶2n−6 metabolism as in G. graminis. CO did inhibit the biosynthesis of 14,15‐di‐HETE, 18‐HETE, and 19‐HETE in L. lacteus, which suggested the involvement of a cytochrome P450‐type monooxygenase. The biosynthesis of 8R‐HODE from 18∶2n−6 was found to occur in certain cell lysates, specifically in low speed (15,000×g) supernatant, following cell disruption.
Fatty acid transport across lipid bilayer planar membranes
Authors: Romano‐Fontes L. G. , Curi R. , Peres C. M. , Nishiyama‐Naruke A. , Brunaldi K. , Abdulkader F. , Procopio J.
Published: November 2006

The transport of palmitic acid (PA) across planar lipid bilayer membranes was measured using a high specific activity [14C]palmitate as tracer for PA. An all‐glass trans chamber was employed in order to minimize adsorbance of PA onto the surface. Electrically neutral (diphytanoyl phosphatidylcholine) and charged (Azolectin) planar bilayers were maintained at open electric circuit. We found a permeability to PA of (8.8±1.9)×10−6 cm s−1 (n=15) in neutral and of (10.3±2.2)×10−6 cm s−1 (n=5) in charged bilayers. These values fall within the order of magnitude of those calculated from desorption constants of PA in different vesicular systems. Differences between data obtained from planar and vesicular systems are discussed in terms of the role of solvent, radius of curvature, and pH changes.
Coordinate packaging of newly synthesized phosphatidylcholine and phosphatidylglycerol in lamellar bodies in alveolar type II cells
Authors: Chander Avinash , Sen Namita , Wadsworth Sandra , Spitzer Alan R.
Published: November 2006

Methylamine, a weak base, inhibits packaging of newly synthesized phosphatidylcholine (PC) in lamellar bodies in 20–22 h cultured alveolar type II cells, suggesting a role for acidic pH of lamellar bodies. In this study, we tested if (i) the packaging of PC is similarly regulated in freshly isolated type II cells and (ii) methylamine also inhibits the packaging of other surfactant phospholipids, particularly, phosphatidylglycerol (PG). The latter would suggest coordinated packaging so as to maintain the phospholipid composition of lung surfactant. During the short‐term metabolic labeling experiments in freshly isolated type II cells, methylamine treatment decreased the incorporation of radioactive precursors into PC, disaturated PC (DSPC), and PG of lamellar bodies but not of the microsomes, when compared with controls. The calculated packaging (the percentage of microsomal lipid packaged in lamellar bodies) of each phospholipid was similarly decreased (∼50%) in methylamine‐treated cells, suggesting coordinated packaging of surfactant phospholipids in lamellar bodies. Equilibrium‐labeling studies with freshly isolated type II cells (as is routinely done for studies on surfactant secretion) ± methylamine showed that in methylamine‐treated cells, the secretion of PC and PG was decreased (possibly due to decreased packaging), but the phospholipid composition of released surfactant (measured by radioactivity distribution) was unchanged; and the PC content (measured by mass or radioactivity) of lamellar bodies was lower, but the PC composition (as percentage of total phospholipids) was unchanged when compared with control cells. We speculate that the newly synthesized surfactant phospholipids, PC, DSPC, and PG, are coordinately transported into lamellar bodies by a mechanism requiring the acidic pH, presumably, of lamellar bodies.
The metabolism and distribution of docosapentaenoic acid (n−6) in rats and rat hepatocytes
Authors: Tam Phyllis S. Y. , Umeda‐Sawada Rumi , Yaguchi Toshiaki , Akimoto Kengo , Kiso Yoshinobu , Igarashi Osamu
Published: November 2006

In this study, a new marine oil that contains 45% docosahexaenoic acid (DHA, 22∶6n−3) and 13% docosapentaenoic acid (DPA, 22∶5n−6) was administered to rats. The metabolism and distribution of DPA in rats was investigated. In experiment 1, the effects of DHA and n−6 fatty acids (linoleic acid, I A; arachidonic acid, AA; and DPA) on AA contents were investigated in vivo. LA group: LA 25%, DHA 30%; LA‐DPA group: LA 15%, DPA 10%, DHA 35%; LA‐AA‐DPA group: LA 10%, AA 5%, DPA 10%, DHA 35% were administered to rats for 4 wk. In the liver, the AA content in the LA‐DPA and LA‐AA‐DPA groups was significantly higher than in the LA group. The decreased AA contents in the LA group might be caused by DHA administration. Although DHA also was administered in the LA‐DPA and LA‐AA‐DPA groups, the AA contents in these two groups did not decrease. These results suggested that DPA retroconverted to AA, blunting the decrease in AA content caused by DHA administration. To conduct a detailed investigation on DPA metabolism and its relation with AA and DHA, rat hepatocytes were cultured with pruified DPA and DHA for 24 h. We discovered the retroconversion of DPA to AA occurred only when AA content was decreased by a high DHA administration; it did not occur when AA content was maintained at a normal level.