bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of different high pressure treatments on shucking, biochemical, physical and sensory characteristics of oysters to elaborate a traditional Taiwanese oyster omelette
Authors: Hsu Kuo‐Chiang , Hwang Jyh‐Sheng , Chi Hsin‐Yi , Lai Kung‐Ming
Published: December 2009

BACKGROUND: Whole oysters (Crassostrea gigas) were processed using high‐pressure (HP) treatment (150–300 MPa) to determine their shucking and biochemical properties. Subsequently, HP‐treated oysters were cooked at 160 °C for 90 s, as when preparing the oyster omelette dish, to evaluate their physical and sensory characteristics as compared to raw oysters.

RESULTS: The treatments of 250 and 300 MPa for 2 min and 0 min, respectively, resulted in 100% release. The pH of HP‐treated oysters increased slightly from 6.50 to 6.82, and the moisture contents of the HP‐treated oysters with or without further cooking were all higher than those of the control. The brightness, yellowness and cutting strength of HP‐treated oysters with further cooking changed insignificantly, while the redness decreased compared to the control. Sensory evaluation showed that oysters treated at 250 and 300 MPa oysters after cooking received higher quality scores than the control.

CONCLUSIONS: HP processing at 250 and 300 MPa proved to be a good method for oyster shucking. The HP‐treated oysters cooked in the oyster omelette are acceptable to consumers. Overall, the application of HP as a processing method to improve the quality and acceptability of oysters and their related products would be possible. Copyright © 2009 Society of Chemical Industry
Polyaniline Morphology and Detectable Intermediate Aggregates
Authors: Ding Zhongfen , Yang Dali , Currier Robert P. , Obrey Stephen J. , Zhao Yusheng
Published: December 2009

Formation of detectable intermediate aggregates is found to affect the morphologies of PANI nanomaterials, leading to either tubular or rod structures with striated growth and rough surfaces. By simply varying the ratio of initial proton and aniline concentration, a wide range of product morphologies can be synthesized. The intermediates form visible aggregates that can be separated by centrifugation or filtration. In addition to UV‐Vis monitoring of the intermediate aggregates, OCP and pH measurements are used to monitor the reaction process. GPC measurements show that the corresponding final products formed typically are not homogeneous. The correlation of intermediates formation and aggregation with product morphology suggests a route to controlled synthesis of PANI nanomaterials.

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Chain Dynamics in Solid Polymers and Polymerizing Systems as Revealed by Broadband Dielectric Spectroscopy
Authors: Williams Graham
Published: December 2009

Broadband Dielectric Spectroscopy (BDS) provides a direct, powerful means of studying the chain dynamics of solid polymers. The present work discusses experimental data, phenomenological theories, molecular theories and recent molecular dynamics simulations of the relaxation functions and average relaxation times for the multiple dielectric relaxations observed for amorphous polymers. Examples of current applications of BDS are given, including studies of the dynamics of ultra‐thin polymer films and real‐time studies of (i) the crystallization behaviour of bulk polymers and (ii) thermo‐polymerizing systems.
The Dynamic Impact Experiments Under Active Confining Pressure and the Constitutive Equation of PP/PA Blends at Multi‐Axial Compressive Stress State
Authors: Shaoqiu Shi , Bing Yu , Lili Wang
Published: December 2009

Summary: A special active hydraulic confining pressure installation matched with Φ14.5 mm SHPB apparatus was developed. A series of active confining pressure impact experiments for PP/PA blends are performed in this special SHPB system under two kinds of axial strain rate: 8.0*102, 1.4*103 s−1 and the active confining pressure of 0 MPa, 4 MPa, 8 MPa, 12 MPa, 15 MPa, 20 MPa. The axial strain‐time profile, the axial stress‐time profile and the hoop strain‐time profile of the specimen are recorded online respectively. According to the equilibrium equation, the complete state of principal stress and principal strain of PP/PA blends under multi‐axial stress state is analyzed.

The experimental results reveal that the axial stress‐strain curves all are related to the confining pressure and the strain rate. It can also be seen that under a constant effective strain rate the effective stress‐ effective strain curves at different confining pressures are coincident basically. This manifests that under a certain effective strain rate there is only one unique effective stress‐ effective strain curve. The multi‐axial constitutive equation for PP/PA blends is suggested finally as:

where σconf is the confining pressure value.

For 113 PP/PA blends, E = 2.98 GPa, α = −31.15 GPa, β = 93.31 GPa, θ2 = 8.54 µS, E2 = 0.82 GPa.
Characterization of Carbon Based Nanoparticles Dispersion in Aqueous Solution Using Dynamic Light Scattering Technique
Authors: Miglietta Maria Lucia , Rametta Gabriella , Di Francia Girolamo
Published: December 2009

Characterization of physicochemical properties of nanoparticles in aqueous environment prior to conducting hazard studies is strongly recommended by many scientific organizations. In this work we studied the dissolution behaviour and physicochemical properties of carbon based nanoparticles in aqueous solution. The time evolution of the size distribution and the state of dispersion of carbon black and carbon nanotubes in physiological solution have been investigated by means of Dynamic Light Scattering technique. The influence of mechanical agitation such as sonication and stirring on the agglomeration state and particle size distribution has been investigated. However, such processes seem to have little or no effect as far as agglomeration is concerned.
Electroless Copper Sulfide Deposition on the Polyacrylonitrile Films with Chelating Agents and its EMI Shielding Effectiveness
Authors: Roan Ming‐Lih , Chen Yen‐Hung , Liao Hao‐Hsiang , Huang Chi‐Yuan , Chen Kan‐Nan , Yeh Jen‐Taut
Published: December 2009

In this study, an effective deposition of copper sulfide (Cux(x = 1,2)S) on the PAN film was proposed by an electroless deposition method with the reduction agents NaHSO3 and Na2S2O3 · 5H2O and chelating agents (ethylenediaminetetraacetic acid, EDTA and triethanolamine, TEA). The mechanism of the Cux(x = 1,2)S growth and the electromagnetic interference shielding effectiveness (EMI SE) of the Cux(x = 1,2)S/PAN films were studied. It was found that the vinyl acetate monomer residue in the PAN substrate would be purged due to the swelling effect by EDTA and TEA solution. And then, the anchoring effect occurred due to the hydrogen bonding between the pits of the PAN substrate and the chelating agent. The swelling degree (Sd) was proposed and evaluated from the FT‐IR spectra. The relationship between swelling degree of the PAN films and EDTA concentration(C) is expressed as: Sd = 0.13 + 0.90 × eˆ(−15.15CEDTA). And TEA series is expressed as: Sd = 0.07 + 1.00 × eˆ(−15.15CTEA). On the other hand, the FESEM micrograph showed that the average thickness of copper sulfide increased from 76 nm to 383 nm when the concentration of EDTA increased from 0.00 M to 0.20 M. Consequently, the EMI SE of the Cux(x = 1,2)S/PAN films increased from 10∼12 dB to 25∼27 dB. The GIA‐XRD analyzer indicated that the deposited layer consisted of CuS and Cu2S.
Processing and Dynamic‐Mechanical Properties of Poly(butylen terephthalate) Based Nanocomposites
Authors: Russo P. , Acierno D. , Gallo E.
Published: December 2009

Effects related to the simultaneous presence of an Al‐phosphinate based fire retardant and of relatively low amounts of nanosized metal oxide particles on processability and mechanical performances of a commercial polyester resin have been investigated. In more details, ternary poly(buthylene terephtalate) based compounds, obtained by melt processing and first of all validated in terms of flammability, were analysed to verify the relative extrudability and ultimate dynamic mechanical performances of compression moulded samples. Preliminary rheological tests confirmed both a minimum of matrix degradation as a result of the process while applying an appropriate protocol drying of raw materials and a marked reduction of the apparent shear viscosity of the three‐phase melts with respect to the neat matrix processed under the same conditions. Regarding the evaluation of dynamic‐mechanical parameters such as storage modulus, loss modulus and the ratio tan δ, besides the expected stiffening of the matrix by inclusion of a rigid inorganic phase, a slight reduction of damping behaviour without no significant variation of the glass transition temperature of the polyester matrix have been observed.
Effect of a Nanodispersed Clay Fillers on Glass Transition of Thermosetting Polyurethane
Authors: Corcione C. Esposito , Maffezzoli A. , Cannoletta D.
Published: December 2009

In this work polyurethane (PU) matrix nanocomposite, obtained using an organically modified montmorillonite (OMM), was synthesized and characterized. An amount of organoclay ranging from 2% up to 6% by volume was added to the polyol component of the resin before mixing with isocyanate. The microstructure of the composites was investigated by X‐ray diffraction. The glass transition temperature (Tg) of PU nanocomposites, measured using differential scanning calorimeter, increases with increasing the volume fraction of OMM. On the other hand, the heat capacity increment, ΔCp, decreases from that the unfilled PU to that of the sample with 5.7% vol of OMM. Therefore a corresponding increase of the rigid amorphous fraction of PU nanocomposites with nanoclay was observed. Finally, the definition of molecular cooperativity was discussed for this system and the characteristic length of the cooperative region was determined, using the approach proposed by Donth.
A Study of the Swelling Properties of Polymer Nanocomposites through Electrical and Optical Characterization
Authors: del Mauro Anna de Girolamo , La Ferrara Vera , Massera Ettore , Miglietta Maria Lucia , Polichetti Tiziana , Rametta Gabriella , Di Francia Girolamo
Published: December 2009

In the present study, polymer nanocomposite layers for sensing applications are characterized by means of an optical method based on white light interferometry. The study focuses on poly (hydroxy ethyl methacrylate) (PHEMA) and on nanocomposite Carbon black (CB)/PHEMA layers commonly used in chemical sensor technology for volatile organic compounds (VOCs) detection. The interferometric spectra of these two different materials, recorded during analyte exposure, are analyzed in terms of film expansion. Comparison between PHEMA and PHEMA/CB layer shows that the nanocomposite undergoes a more pronounced swelling process. In order to achieve a better comprehension of the sensing mechanism and to improve the sensor performances, the variations of the electrical signal of a nanocomposite‐based chemiresistor in presence of VOCs are examined and compared to the optical behaviour.
Oleuropein and hydroxytyrosol inhibit MCF‐7 breast cancer cell proliferation interfering with ERK1/2 activation
Authors: Sirianni Rosa , Chimento Adele , De Luca Arianna , Casaburi Ivan , Rizza Pietro , Onofrio Arianna , Iacopetta Domenico , Puoci Francesco , Andò Sebastiano , Maggiolini Marcello , Pezzi Vincenzo
Published: December 2009

The growth of many breast tumors is stimulated by estradiol (E2), which activates a classic mechanism of regulation of gene expression and signal transduction pathways inducing cell proliferation. Polyphenols of natural origin with chemical similarity to estrogen have been shown to interfere with tumor cell proliferation. The aim of this study was to investigate whether hydroxytyrosol (HT) and oleuropein (OL), two polyphenols contained in extra‐virgin olive oil, can affect breast cancer cell proliferation interfering with E2‐induced molecular mechanisms. Both HT and OL inhibited proliferation of MCF‐7 breast cancer cells. Luciferase gene reporter experiments, using a construct containing estrogen responsive elements able to bind estrogen receptor alpha (ERα) and the study of the effects of HT or OL on ERα expression, demonstrated that HT and OL are not involved in ERα‐mediated regulation of gene expression. However, further experiments pointed out that both OL and HT determined a clear inhibition of E2‐dependent activation of extracellular regulated kinase1/2 belonging to the mitogen activating protein kinase family. Our study demonstrated that HT and OL can have a chemo‐preventive role in breast cancer cell proliferation through the inhibition of estrogen‐dependent rapid signals involved in uncontrolled tumor cell growth.
Lupine, a source of new as well as hidden food allergens
Authors: Jappe Uta , Vieths Stefan
Published: December 2009

The present review summarizes current knowledge about lupine allergy, potential sensitization routes, cross‐reactions between lupine and other legumes, and the respective IgE‐binding proteins. Since the 1990s, lupine flour is used as a substitute for or additive to other flours, mostly wheat flour, in several countries of the EU. In 1994, the first case of an immediate‐type allergy after ingestion of lupine flour‐containing pasta was reported. Since then, the number of published incidents following ingestion or inhalation of lupine flour is rising. So far, the Lupinus angustifolius β‐conglutin has been designated as the allergen Lup an 1 by the International Union of Immunological Societies Allergen Nomenclature Subcommittee. Initially, publications focussed on the fact that peanut‐allergic patients were at risk to develop anaphylaxis to lupine due to cross‐reactivity between peanut and lupine. At present, however, the ratio between cases of pre‐existing legume allergy (mostly peanut allergy) to de novo sensitization to lupine seed is nearly 1:1. Although in December 2006, lupine and products thereof were included in the EU foodstuff allergen list according to the Commission Directive 2006/142/EC amending Annex IIIA of Directive 2000/13/EC in order to prevent severe reactions caused by “hidden food allergens”, the majority of patients and medical personnel are still not aware of raw lupine seed as potentially dangerous food allergen.
Pyrrolizidine alkaloids (PAs) in honey and pollen‐legal regulation of PA levels in food and animal feed required
Authors: Kempf Michael , Reinhard Annika , Beuerle Till
Published: December 2009

Pyrrolizidine alkaloids (PAs) are secondary plant constituents that comprise about 400 different structures and occur in two major forms, a tertiary form and the corresponding N‐oxide. PAs containing a 1,2‐double bond are pre‐toxins and metabolically activated by the action of hepatic P‐450 enzymes to toxic pyrroles. Besides the acute toxic effects, the genotoxic and tumorigenicity potential of PAs was demonstrated in some eukaryotic model systems. Recently, the potential PA contamination of food and feeding stuff attracted recurrent great deals of attention. Humans are exposed to these toxins by consumption of herbal medicine, herbal teas, dietary supplements or food containing PA plant material. In numerous studies the potential threat to human health by PAs is stated. In pharmaceuticals, the use of these plants is regulated. Considering the PA concentrations observed especially in authentic honey from PA producing plants and pollen products, the results provoke an international regulation of PAs in food.
Von Ärzteprivileg bis Zwangslizenzen
Authors: Schneider Michael
Published: December 2009

Für Pharmaerfindungen gibt es kein Spezialpatentrecht, wohl aber einige Besonderheiten

im Rahmen der normalen Regelungen.
Das Prinzip Katalyse
Authors: Quadbeck‐Seeger Hans‐Jürgen
Published: December 2009

Hans‐Jürgen Quadbeck‐Seeger

Die Katalyse zählt zu den geheimnisvollsten Phänomenen der Natur, dennoch wird ihre fundamentale Bedeutung meist unterschätzt. Dabei steht fest: Das Leben wäre ohne die Katalyse und die darauf aufbauende Selbstorganisation der Materie nicht möglich.
Protein‐Ligand‐Komplexe und Proteine dreidimensional
Authors: Koch Oliver
Published: December 2009

Die Datenbank Relibase bietet Such‐ und Analysefunktionen. Strukturen aus der öffentlich zugänglichen Proteindatenbank sind integriert, eigene Strukturdaten lassen sich hinzufügen.
Neue Bedingungen für Laborsynthesen
Authors: Stadler Alexander
Published: December 2009

In der Mikrowellensynthese sind nun höhere Drücke und Temperaturen möglich, und es sind unpolare Lösungsmittel einsetzbar.
Improving algebraic multigrid interpolation operators for linear elasticity problems
Authors: Baker A. H. , Kolev Tz. V. , Yang U. M.
Published: December 2009

Linear systems arising from discretizations of systems of partial differential equations can be challenging for algebraic multigrid (AMG), as the design of AMG relies on assumptions based on the near‐nullspace properties of scalar diffusion problems. For elasticity applications, the near‐nullspace of the operator includes the so‐called rigid body modes (RBMs), which are not adequately represented by the classical AMG interpolation operators. In this paper we investigate several approaches for improving AMG convergence on linear elasticity problems by explicitly incorporating the near‐nullspace modes in the range of the interpolation. In particular, we propose two new methods for extending any initial AMG interpolation operator to exactly fit the RBMs based on the introduction of additional coarse degrees of freedom at each node. Though the methodology is general and can be used to fit any set of near‐nullspace vectors, we focus on the RBMs of linear elasticity in this paper. The new methods can be incorporated easily into existing AMG codes, do not require matrix inversions, and do not assume an aggregation approach or a finite element framework. We demonstrate the effectiveness of the new interpolation operators on several 2D and 3D elasticity problems. Copyright © 2009 John Wiley & Sons, Ltd.
What's in a name? Qualitative description revisited
Authors: Sandelowski Margarete
Published: December 2009

“Whatever Happened to Qualitative Description?” (Sandelowski, 2000) was written to critique the prevailing tendency in qualitative health research to claim the use of methods that were not actually used and to clarify a methodological approach rarely identified as a distinctive method. The article has generated several misconceptions, most notably that qualitative description requires no interpretation of data. At the root of these misconceptions is the persistent challenge of defining qualitative research methods. Qualitative description is a “distributed residual category” (Bowker & Star, 2000). Cambridge, MA: The MIT Press) in the classification of these methods. Its value lies not only in the knowledge its use can produce, but also as a vehicle for presenting and treating research methods as living entities that resist simple classification. © 2009 Wiley Periodicals, Inc. Res Nurs Health 33:77–84, 2010
Polystyrene‐wrapping multi‐walled carbon nanotubes obtained via simple physical modification of melt mixing
Authors: Zhou Tian‐nan , Hou Zai‐chuan , Wang Ke , Zhang Qin , Fu Qiang
Published: December 2009

Melt mixing with a polymer is a novel strategy to modify the surface property of carbon nanotube (CNT) conveniently and efficiently. In melt mixing process, the shearing and thermal issues can make polymer component wrapped around nanotubes via π–π stacking interaction. In this study, polystyrene‐coated multi‐walled carbon nanotubes (MWNTs) was achieved through simple melt mixing of polystyrene with MWNTs. PS and MWNTs were first melt mixed at various melt time and temperatures to find the optimum condition for preparing of PS‐coated MWNTs. Subsequently, the stability of polystyrene interacted with MWNTs was estimated via ultrasonication and thermal gravimetric analysis (TGA). Finally, the physically modified MWNTs were used to enhance polystyrene. An obvious mechanical reinforcement can be achieved, which approves a huge potential of application of these modified MWNTs in practical composite products. Copyright © 2009 John Wiley & Sons, Ltd.
Electrically and thermally modulated optical properties of polymer dispersed chiral liquid crystal
Authors: Zhang B.Y. , Wang J.H. , Xu X.Y. , Xi M.
Published: December 2009

The polymer dispersed chiral liquid crystals (PDCLCs) film was fabricated by photopolymerization induced phase separation (PIPS) of chiral liquid crystal (CLC)/polymerizable monomers/photoinitiator composites. The effects of the electrical and thermal modulation on optical rotation properties of PDCLCs film were investigated. The microsized liquid crystal droplets were resulted from the rapid polymerization of trifunctional monomers. The effects of the electrically and thermally modulated on realignment of liquid crystal director were investigated. It was found that the intensity of electric and thermal field influenced the alignment of liquid crystal droplets' director on PDCLCs film, and the electro‐optical properties of the composites were affected accordingly. The principle of free energy minimum was used for explaining the change of optical rotation and transmittance of PDCLCs film with applying the voltage to the film. The dispersion and sizes of liquid crystal droplets were described by polarizing optical microscope (POM). POLYM. COMPOS., 31:1535–1540, 2010. © 2009 Society of Plastics Engineers
An investigation of the mechanical behavior of carbon epoxy cross ply cruciform specimens under biaxial loading
Authors: Makris Andreas , Ramault Carla , Van Hemelrijck Danny , Zarouchas Dimitrios , Lamkanfi Ebrahim , Van Paepegem Wim
Published: December 2009

In this study, carbon epoxy cruciform type specimens with a cross‐ply layup were biaxially and uniaxially in‐plane loaded using four independent servo‐hydraulic actuators. Four different biaxial loading ratios were investigated when the applied load was quasi‐static. A comparison between experimental observations (for the damage and strain evolution of the biaxially loaded central section of the specimen) coming from digital image correlation measurements and a 3D finite element damage model will be shown. The symmetry and the uniformity of the strain field on the biaxially loaded zone were by the use of digital image correlation measurements investigated. Furthermore, the failure loads coming from the load cells of the machine were straightforward compared with the output of the finite element damage model. POLYM. COMPOS., 31:1554–1561, 2010. © 2009 Society of Plastics Engineers
Void formation model and measuring method of void formation condition during hot pressing process
Authors: Gu Yizhuo , Li Min , Zhang Zuoguang , Sun Zhijie
Published: December 2009

For resin matrix composites, voids are common defects that can seriously deteriorate the properties of the composite parts. Thus, the elimination of voids is a crucial element in controlling the manufacturing process of composite parts. This article focuses on void formation originating from hygroscopic water for resin matrix composite laminates prepared with hot pressing process. The Kardos void formation model was developed to analyze the critical resin pressure for the initiation of voids, and the influencing factors were investigated experimentally to validate the modified model. It is found that resin pressure and gel temperature are the two key parameters to control void defects and that entrapped air in prepreg stacks must be considered in the void formation model. Furthermore, a simple method was established to measure the relationship between porosity and the processing parameters, and the void formation conditions of the resin and the prepreg stack were also studied. The theoretically predicted void formation conditions and the experimental results were compatible for the studied cases. These results are valuable for eliminating void defects, optimizing processing parameters, and enhancing the performance of composite parts. POLYM. COMPOS., 31:1562–1571, 2010. © 2009 Society of Plastics Engineers
Nanometer‐thick patterned conductive films prepared through the self‐synthesis of polythiophene derivatives
Authors: Liu Cheng‐Dar , Huang Chih‐Kai , Wu Sheng‐Yen , Han Jin‐Lin , Hsieh Kuo‐Huang
Published: December 2009

The development of flexible electronics requires the patterning of conductive and active semiconductor films. Although inorganic materials such as indium tin oxide and metal nanoparticles have high conductivity and transparency, their poor interfacial adhesion with organic layers, lack of flexibility, high weight and high capital costs are drawbacks. In contrast, organic conducting polymers have great potential for use in commercial flexible electronic applications because of their low production costs, environmental stability and acceptable conductivities. A UV‐curable photoresist containing hydroxyl groups was prepared from a mixture of a photoinitiator, epoxy‐acrylate resin, hydroxyethyl methacrylate and tripropylene glycol diacrylate. Patterns having line widths/spaces of 100/100 µm and 10/5 µm were fabricated on a poly(ethylene terephthalate) (PET) substrate using lithography techniques. (3‐Methyl‐3,4‐dihydro‐2H‐thieno[3,4‐b]dioxepin‐3‐yl)methanol (ProDOT‐OH) was self‐synthesized through urethane linkages onto the surface of the patterned photoresist on the PET film, which was then dipped into a solution of another monomer, 3‐thienylethoxybutanesulfonate (TEBS), and initiator and polymerized in situ to form conductive poly(ProDOT‐OH‐co‐TEBS) films covering the surface of the patterned resist. The optimal conductivity of the poly(ProDOT‐OH‐co‐TEBS) films was ca 90 S cm−1 with an optical transparency of ca 70%. A new bottom‐up technique has been developed for the preparation of patterned organic transparent conductive films: self‐synthesis of the monomer using urethane‐forming reactions and subsequent in situ polymerization. The conductivity of the films can be controlled by the polymerization reaction time and the resolution of the pattern. These conductive patterned films might be applicable to the manufacture of industrial touch panels or chemical/biological sensors. Copyright © 2009 Society of Chemical Industry
Polymeric coatings for photostability enhancement of poly(p‐phenylene vinylene) derivative films
Authors: Gonçalves Vanessa C , Carvalho Antonio JF , Balogh Debora T
Published: December 2009

Poly(p‐phenylene vinylene) (PPV) derivatives are an important class of conjugated polymers, known for their applications as electroluminescent materials for light‐emitting devices and sensors. These derivatives are highly susceptible to photodegradation by the combined action of oxygen and light. Here, the use of various commercial polymers as protective coatings against the photodegradation of PPV derivatives was explored. Cast films of two similar PPV derivatives, poly[(2‐methoxy‐5‐n‐hexyloxy)‐p‐phenylene vinylene] and poly[2‐methoxy‐5‐(2‐ethylhexyloxy)‐p‐phenylene vinylene], were submitted to photodegradation by exposure to white light under atmospheric conditions in order to verify if the type of side chain (linear or branched) had an effect on the photodegradation. No significant differences in the photodegradation behaviour between the two polymers were noticed. The following commercial polymers were tested as protective coatings for the PPV derivative cast films: 99 and 80% hydrolysed poly(vinyl alcohol) (PVA) and starch. The best results were achieved using coatings of 99% hydrolysed PVA, which increased about 700 times the time necessary for complete degradation of the PPV derivative films. The results show the effectiveness of this coating in minimizing and, possibly, controlling the effects of the photodegradation of PPV derivative films, which can be useful in many applications, e.g. oxygen sensors. Copyright © 2009 Society of Chemical Industry
Versatile modes of peptide recognition by the ClpX N domain mediate alternative adaptor‐binding specificities in different bacterial species
Authors: Chowdhury Tahmeena , Chien Peter , Ebrahim Shamsah , Sauer Robert T. , Baker Tania A.
Published: December 2009

ClpXP, an AAA+ protease, plays key roles in protein‐quality control and many regulatory processes in bacteria. The N‐terminal domain of the ClpX component of ClpXP is involved in recognition of many protein substrates, either directly or by binding the SspB adaptor protein, which delivers specific classes of substrates for degradation. Despite very limited sequence homology between the E. coli and C. crescentus SspB orthologs, each of these adaptors can deliver substrates to the ClpXP enzyme from the other bacterial species. We show that the ClpX N domain recognizes different sequence determinants in the ClpX‐binding (XB) peptides of C. crescentus SspBα and E. coli SspB. The C. crescentus XB determinants span 10 residues and involve interactions with multiple side chains, whereas the E. coli XB determinants span half as many residues with only a few important side chain contacts. These results demonstrate that the N domain of ClpX functions as a highly versatile platform for peptide recognition, allowing the emergence during evolution of alternative adaptor‐binding specificities. Our results also reveal highly conserved residues in the XB peptides of both E. coli SspB and C. crescentus SspBα that play no detectable role in ClpX‐binding or substrate delivery.
Insight into the structure of the pUL89 C‐terminal domain of the human cytomegalovirus terminase complex
Authors: Couvreux A. , Hantz S. , Marquant R. , Champier G. , Alain S. , Morellet N. , Bouaziz S.
Published: December 2009

In a previous study, we identified 12 conserved domains within pUL89, the small terminase subunit of the human cytomegalovirus. A latter study showed that the fragment pUL89(580–600) plays an important role in the formation of the terminase complex by interacting with the large terminase subunit pUL56. In this study, analysis was performed to solve the structure of pUL89(568–635) in 50% H2O/50% acetonitrile (v/v). We showed that pUL89(568–635) consists of four alpha helices, but we did not identify any tertiary structure. The fragment 580–600 formed an amphipathic alpha helix, which had a hydrophobic side highly conserved among herpesviral homologs of pUL89; this was not observed for its hydrophilic side. The modeling of pUL89(457–612) using the recognition fold method allowed us to position pUL89(580–600) within this domain. The theoretical structure highlighted three important features. First, we identified a metal‐binding pocket containing residues Asp463, Glu534, and Glu588, which are highly conserved among pUL89 homologs. Second, the model predicted a positively charged surface able to interact with the DNA duplex during the nicking event. Third, a hydrophobic patch on the top of the catalytic site suggested that this may constitute part of the pUL89 site recognized by pUL56 potentially involved in DNA binding. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Potential attractants for detecting and removing invading Gambian giant pouched rats (Cricetomys gambianus)
Authors: Witmer Gary W , Snow Nathan P , Burke Patrick W
Published: December 2009

BACKGROUND: Native to Africa, Gambian giant pouched rats (Gambian rats; Cricetomys gambianus Waterh.) are a threatening invasive species on a Florida island, Grassy Key. Gambian giant pouched rats shifted from a domestic pet to invading species after suspected release from a pet breeder. Because of the large size of Gambian rats (weighing up to 2.8 kg), they pose a serious threat to native species (particularly nesting species) and agricultural crops, especially if Gambian rats invade mainland Florida. Also, Gambian rats pose a threat from disease, as they were implicated in a monkeypox outbreak in the midwestern United States in 2003. The United States Department of Agriculture's Wildlife Services has initiated eradication and detection efforts in the Florida Keys, but trapping the sparse population of Gambian rats has proven difficult.

RESULTS: Fifteen attractants that could be used in traps for capturing or detecting single or paired Gambian rats were tested. It was found that conspecific scents (i.e. feces and urine) from other Gambian rats were the best treatment for attracting single and paired Gambian rats. Single Gambian rats explored more attractant types than paired Gambian rats.

CONCLUSIONS: Effective attractants for use with Gambian rats have been identified, and multiple attractant types should be used to capture or detect the sparse population. It is recommended that mainly urine and feces from Gambian rats be used, but peanut butter, anise, ginger and fatty acid scent could also be useful for attracting the currently small population of Gambian rats on Grassy Key. Published in 2009 by John Wiley & Sons, Ltd.
Adipokinetic hormone (Pyrap‐AKH) enhances the effect of a pyrethroid insecticide against the firebug Pyrrhocoris apterus
Authors: Kodrík Dalibor , Bártů Iva , Socha Radomír
Published: December 2009

BACKGROUND: Adipokinetic hormones (AKHs) are insect neuropetides controlling stress situations including those elicited by insecticide treatment. The effect of Pyrap‐AKH on the mortality of the firebug Pyrrhocoris apterus (L.) treated with the insecticide permethrin (Ambush 25 EC) was studied.

RESULTS: Coinjection of 50 ng permethrin with 80 pmol Pyrap‐AKH induced a significant 2.3‐fold increase in bug mortality compared with the insecticide alone. The results were confirmed by topical coapplication of both agents (400 ng and 80 pmol respectively). Injections of 50 and 100 ng permethrin elicited a significant increase in the AKH level in CNS and the haemolymph. The results indicate an involvement of AKH in stress response to permethrin. The enhanced effect of insecticide by AKH treatments probably results from the stimulatory role in bug metabolism: carbon dioxide production was increased 3.5‐ and 2.5‐fold respectively 1 and 3 h after permethrin treatment, and 4.3‐ and 3.4‐fold after the permethrin plus AKH cotreatment, compared with the control.

CONCLUSION: The elevation of metabolism could intensify the permethrin action by its faster penetration into tissues and by stimulation of biochemically active cells, and could be a reason for enhanced action of permethrin after its cotreatment with Pyrap‐AKH. Copyright © 2009 Society of Chemical Industry
Reduction of bias in static closed chamber measurement of δ13C in soil CO2 efflux
Authors: Ohlsson K. E. Anders
Published: December 2009

The 13C/12C ratio of soil CO2 efflux (δe) is an important parameter in studies of ecosystem C dynamics, where the accuracy of estimated C flux rates depends on the measurement uncertainty of δe. The static closed chamber method is frequently used in the determination of δe, where the soil CO2 efflux is accumulated in the headspace of a chamber placed on top of the soil surface. However, it has recently been shown that the estimate of δe obtained by using this method could be significantly biased, which potentially diminish the usefulness of δe for field applications. Here, analytical and numerical models were used to express the bias in δe as mathematical functions of three system parameters: chamber height (H), chamber radius (Rc), and soil air‐filled porosity (θ). These expressions allow optimization of chamber size to yield a bias, which is at a level suitable for each particular application of the method. The numerical model was further used to quantify the effects on the δe bias from (i) various designs for sealing of the chamber to ground, and (ii) inclusion of the commonly used purging step for reduction of the initial headspace CO2 concentration. The present modeling work provided insights into the effects on the δe bias from retardation and partial chamber bypass of the soil CO2 efflux. The results presented here supported the continued use of the static closed chamber method for the determination of δe, with improved control of the bias component of its measurement uncertainty. Copyright © 2009 John Wiley & Sons, Ltd.
Use of bio‐traps with multiple substrates and electron acceptors to optimize remediation
Authors: Fiorenza Stephanie , McClary Amy C. , Lummus Stanford
Published: December 2009

Bio‐Traps® were used to investigate biodegradation of benzene, methyl tertiary butyl ether (MTBE), and tertiary butyl alcohol (TBA) under different conditions at a fractured rock site to aid the selection of a bioremediation approach. The Bio‐Traps were amended with the 13C‐labeled constituent of interest and sampled sequentially at 15‐, 30‐, 60‐, and 90‐day intervals. The conditions tested were biodegradation during operation of an air sparge system, amendment with nitrate during the air sparge operation, anaerobic biodegradation with the system turned off, and anaerobic biodegradation with nitrate amendment. There was increased biomass with nitrate amendment whether the air sparge system was on or off for all the constituents of interest. The diversity of the microbial community, determined by phospholipid fatty acid analysis, decreased with nitrate amendment as more specialized degraders were selected. The most negative indicators of potential biodegradation performance were observed with the anaerobic control. There was less biomass overall, less incorporation of 13C into biomass, and decreased membrane permeability. As testing with additional amendments continues at the site, it is not yet certain which treatment might be selected for bioremediation, but the Bio‐Trap tests thus far have identified that the in situ, natural attenuation condition is least favorable for biodegradation. © 2009 Wiley Periodicals, Inc.
Evaluation of algal phytoremediation of light extractable petroleum hydrocarbons in subarctic climates
Authors: Jacques Nicole R. , McMartin Dena W.
Published: December 2009

The presence of an organic mat in a hydrocarbon‐impacted creek in Whitehorse, Yukon Territory, Canada was examined for contributions to in situ remediation of petroleum‐contaminated water. This article investigates the role of algae, found in the organic mat, in the remediation of light extractable petroleum hydrocarbons (LEPHs) at the site and in the laboratory. During the study, LEPH concentrations were reduced by 16.8 percent in the presence of algae alone (algal solution) and 30.4 percent in the combined organic mat solution containing microbial consortia. The study results indicate that algal species at the site did not directly phytoremediate hydrocarbons. Rather, they were part of the total biological degradation taking place. © 2009 Wiley Periodicals, Inc.
Application of nonparametric quantile regression to body mass index percentile curves from survey data
Authors: Li Yan , Graubard Barry I. , Korn Edward L.
Published: December 2009

Increasing rates of overweight among children in the U.S. stimulated interest in obtaining national percentile curves of body size to serve as a benchmark in assessing growth development in clinical and population settings. In 2000, the U.S. Centers for Disease Control and Prevention (CDC) developed conditional percentile curves for body mass index (BMI) for ages 2–20 years. The 2000 CDC BMI‐for‐age curves are partially parametric and only partially incorporated the survey sample weights in the curve estimation. As a result, they may not fully reflect the underlying pattern of BMI‐for‐age in the population. This motivated us to develop a nonparametric double‐kernel‐based method and automatic bandwidth selection procedure. We include sample weights in the bandwidth selection, conduct median correction to reduce small‐sample smoothing bias, and rescale the bandwidth to make it scale invariant. Using this procedure we re‐estimate the national percentile BMI‐for‐age curves and the prevalence of high‐BMI children in the U.S. Copyright © 2009 John Wiley & Sons, Ltd.
KMT1E Mediated H3K9 Methylation Is Required for the Maintenance of Embryonic Stem Cells by Repressing Trophectoderm Differentiation
Authors: Lohmann Felix , Loureiro Joseph , Su Hui , Fang Qing , Lei Hong , Lewis Tanya , Yang Yi , Labow Mark , Li En , Chen Taiping , Kadam Shilpa
Published: December 2009

Dynamic regulation of histone methylation by methyltransferases and demethylases plays a central role in regulating the fate of embryonic stem (ES) cells. The histone H3K9 methyltransferase KMT1E, formerly known as ESET or Setdb1, is essential to embryonic development as the ablation of the Setdb1 gene results in peri-implantation lethality and prevents the propagation of ES cells. However, Setdb1-null blastocysts do not display global changes in H3K9 methylation or DNA methylation, arguing against a genome-wide defect. Here we show that conditional deletion of the Setdb1 gene in ES cells results in the upregulation of lineage differentiation markers, especially trophectoderm-specific factors, similar to effects observed upon loss of Oct3/4 expression in ES cells. We demonstrate that KMT1E deficiency in ES cells leads to a decrease in histone H3K9 methylation at and derepression of trophoblast-associated genes such as Cdx2. Furthermore, we find genes that are derepressed upon Setdb1 deletion to overlap with known targets of polycomb mediated repression, suggesting that KMT1E mediated H3K9 methylation acts in concert with polycomb controlled H3K27 methylation. Our studies thus demonstrate an essential role for KMT1E in the control of developmentally regulated gene expression programs in ES cells.
Stochastic approaches in systems biology
Authors: Ullah Mukhtar , Wolkenhauer Olaf
Published: December 2009

The discrete and random occurrence of chemical reactions far from thermodynamic equilibrium, and low copy numbers of chemical species, in systems biology necessitate stochastic approaches. This review is an effort to give the reader a flavor of the most important stochastic approaches relevant to systems biology. Notions of biochemical reaction systems and the relevant concepts of probability theory are introduced side by side. This leads to an intuitive and easy‐to‐follow presentation of a stochastic framework for modeling subcellular biochemical systems. In particular, we make an effort to show how the notion of propensity, the chemical master equation (CME), and the stochastic simulation algorithm arise as consequences of the Markov property. Most stochastic modeling reviews focus on stochastic simulation approaches—the exact stochastic simulation algorithm and its various improvements and approximations. We complement this with an outline of an analytical approximation. The most common formulation of stochastic models for biochemical networks is the CME. Although stochastic simulations are a practical way to realize the CME, analytical approximations offer more insight into the influence of randomness on system's behavior. Toward that end, we cover the chemical Langevin equation and the related Fokker–Planck equation and the two‐moment approximation (2MA). Throughout the text, two pedagogical examples are used to key illustrate ideas. With extensive references to the literature, our goal is to clarify key concepts and thereby prepare the reader for more advanced texts. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Analytical and Computational Methods > Computational Methods
Pancreatitis bundles
Authors: Mayumi Toshihiko , Takada Tadahiro , Hirata Koichi , Yoshida Masahiro , Sekimoto Miho , Hirota Masahiko , Kimura Yasutoshi , Takeda Kazunori , Amano Hodaka , Wada Keita , Gabata Toshifumi , Arata Shinjyu , Hirota Morihisa , Yokoe Masamichi , Kiriyama Seiki , Shikata Satoru , Shirai Kunihiro , Nakayama Takeo , Ohtomo Kuni , Tanaka Masao , Shimosegawa Tooru
Published: December 2009

Clinical indicators set forth in the guidelines have been found to contribute to the improvement in compliance with the guidelines. On the other hand, it has been shown that clinical indicators are more effective when individual indicators are presented in the form of a bundle than when they are given separately. Accordingly, in the JPN Guidelines 2010 for management of acute pancreatitis, those indicators that are judged to be important on the basis of a recommendation classification of “A or B” are presented as a pancreatitis bundle. Each item includes assessment of severity after a diagnosis of pancreatitis has been made, differentiation of pathogenesis, management of gallstone‐induced pancreatitis, a sufficient dose of fluid replacement and monitoring, pain control, prophylactic administration of wide‐spectrum antibiotics and cholecystectomy following resolution of pancreatic symptoms caused by cholecystolithiasis. Hereafter, the efficacy of these indicators and the significance of their achievement should be examined carefully. Then, the assessment of the compliance rate with the guidelines as well as the assessment of the guidelines and pancreatitis itself should become possible.
Posterior Ankle Impingement: Clarification and Confirmation of the Pathoanatomy
Authors: Sofka Carolyn M.
Published: December 2009

The diagnosis of posterior hindfoot pain may prove to be elusive as there are many potential causes of hindfoot pain, including both soft tissue and osseous abnormalities. This is a case presentation of os trigonum syndrome, with the diagnosis suggested by magnetic resonance imaging (MRI), confirmed by ultrasound, and treated with os trigonum resection. Specific findings of os trigonum syndrome can be seen on MRI, including bone marrow edema pattern and high signal intensity in the synchondrosis as well as in the surrounding soft tissues. Diagnostic injections performed with imaging guidance can help confirm the diagnosis in equivocal cases. Diagnostic and interventional imaging procedures can help confirm the diagnosis of os trigonum syndrome in a patient presenting with hindfoot pain.
The Consumption of Food Products from Linseed‐Fed Animals Maintains Erythrocyte Omega‐3 Fatty Acids in Obese Humans
Authors: Legrand Philippe , Schmitt B. , Mourot J. , Catheline D. , Chesneau G. , Mireaux M. , Kerhoas N. , Weill P.
Published: December 2009

Based on mechanistic and epidemiological data, we raise the question of the relationship between qualitative dietary polyunsaturated fatty acids (PUFA) changes and increase in obesity. In this double‐blind trial, we studied the effects on 160 overweight volunteers (body mass index, BMI >30) of a 90 days experimental diet rich principally in animal fat with a low PUFA/saturated fatty acid (SFA) ratio but a low n‐6/n‐3 ratio, using animal products obtained from linseed‐fed animals. The control diet provided less animal fat, a higher PUFA/SFA ratio and a higher n‐6/n‐3 ratio. Both diets excluded seafood. In the experimental group, we observed a significant increase in red blood cell (RBC) α‐linolenic acid content and a slight increase in EPA and DHA derivatives, while in the control group we observed a significant reduction in EPA and DHA content. Between groups now, the difference in the three n‐3 fatty acids changes in RBC was significant. This demonstrates that plasma EPA and DHA levels can be maintained without fish if products from linseed‐fed animals are used. During the diets, we noted a significant reduction in weight, BMI and hip circumference within both groups of volunteers. However, no significant difference was observed between the control group and the experimental group. Interestingly, 150 days after the end of the trial (i.e., day 240), we noted a significant weight gain in the control group, whereas no significant weight gain was observed in the experimental group. This was also observed for the BMI and hip circumference. Moreover, significant differences in BMI (P < 0.05) and weight (P = 0.05) appeared between the two groups, showing in both cases a smaller increase in the experimental group. During the 90 days trial, we did not observe any differences between groups in terms of total cholesterol, HDL cholesterol, LDL cholesterol or triglycerides, suggesting that the saturate content and the P/S ratio are not as important as the n‐6 and n‐3 fatty acid composition.