bluuebunny/crossref_metadata_2025 huggingface dataset:
Methyltrioxorhenium(VII) in Oxidation Catalysis
Authors: Kuehn Fritz E.
Published: August 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Organometallic Chemistry of Water
Authors: Kuehn Fritz E. , Herrmann Wolfgang A.
Published: August 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Palladium‐Catalyzed Alkenylation by the Negishi Coupling
Authors: Negishi Ei‐ichi , Hu Qian , Huang Zhihong , Qian Mingxing , Wang Guangwei
Published: August 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Noncovalent Interactions of Molecules with Single Walled Carbon Nanotubes
Authors: Britz David A. , Khlobystov Andrei N.
Published: August 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Recent Progress in Application of Spectroscopic Methods for Assigning Absolute Configuration of Optically Active Sulfoxides
Authors: Donnoli Maria Irene , Superchi Stefano , Rosini Carlo
Published: August 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Can Raman Optical Activity Separate Axial from Local Chirality? A Theoretical Study of Helical Deca‐Alanine
Authors: Herrmann Carmen , Ruud Kenneth , Reiher Markus
Published: August 2006

Motivated by experimental work on the distinction of protein secondary structure motifs by Raman optical activity (ROA) spectroscopy, we demonstrate using density functional theory that axial chirality in structures with different local chirality can be filtered out by ROA spectroscopy. To this purpose, two diastereomers of right‐handed helical deca‐alanine, the (all‐S) and the (R,S,R,S,R,S,R,S,R,S) form, are compared. Furthermore, we suggest to interpret calculated ROA spectra of large molecules in terms of vibrational bands rather than individual peaks. This is due to the non‐homogeneous effect of the harmonic approximation as well as of the chosen electronic structure method onto the vibrational frequencies, which in a dense region of many vibrations will strongly determine the shape of the spectrum. In addition, the calculated ROA spectrum of (all‐S)‐deca‐alanine is compared to the experimental spectrum of poly‐(L)‐alanine in solution.
Clues to Dimetallohydrolase Mechanisms from Studies on Pyrazolate‐Based Bioinspired Dizinc Complexes – Experimental Evidence for a Functional Zn–O2H3–Zn Motif
Authors: Meyer Franc
Published: August 2006

Various hydrolytic metalloenzymes contain two adjacent zinc ions within their active site that work synergistically during substrate turnover. While structural biology, biochemical investigations, and quantum chemical calculations have provided much insight into those cocatalytic sites, crucial details of the catalytic mechanisms have remained under debate. Valuable contributions to further our understanding of the functional role of the zinc ions in a specific coordination environment can be obtained from the study of simple biomimetic synthetic complexes that emulate features of the natural systems. To this end, a series of highly preorganized pyrazolate‐based dizinc complexes has been developed, which are particularly amenable to fine‐tuning of the dimetallic core. These bioinspired dizinc complexes have made possible the investigation of systematic effects of factors such as the zinc–zinc separation on hydrolytic activity and substrate binding. The present microreview summarizes findings relevant to dimetallohydrolases that have been obtained from studies of the pyrazolate‐based synthetic analogues, including experimental support for a functional role of the Zn–O2H3–Zn motif and clues to the binding and hydrolytic cleavage of phosphodiester and β‐lactam substrates. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Disgust, creatureliness and the accessibility of death‐related thoughts
Authors: Cox Cathy R. , Goldenberg Jamie L. , Pyszczynski Tom , Weise David
Published: August 2006

From an existential terror management theory perspective, disgusting stimuli are threatening to human beings because they make salient people's vulnerability to death. Two studies were designed to assess this proposition by measuring implicit death‐related ideation after individuals were presented with stimuli that either were or were not disgusting, under conditions in which the similarities of humans to other animals or the uniquely human aspects of people were made salient. In Study 1, in which rather extreme disgust‐eliciting pictures were used, disgusting stimuli led to higher death‐thought accessibility than neutral pictures regardless of whether or not participants had previously been primed with similarities between humans and other animals. In Study 2, in which milder verbal disgust‐eliciting stimuli were used, disgusting stimuli led to heightened death‐thought accessibility only when human‐animal similarities were first primed. Implications for the regulation and humanization of the human body and its functions are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Lithium augmentation of topiramate for bipolar disorder with comorbid binge eating disorder and obesity
Authors: Kotwal Renu , Guerdjikova Anna , McElroy Susan L. , Keck Paul E.
Published: August 2006

Objective

To evaluate the effectiveness of lithium augmentation of topiramate on mood symptoms, binge eating behavior, and body weight in obese bipolar patients with binge eating disorder (BED) seeking weight management.

Method

We conducted a naturalistic study of 12 consecutive outpatients with bipolar disorders, BED, and obesity who received lithium augmentation for mood instability during the course of topiramate‐based pharmacotherapy for obesity and BED. Lithium was added to topiramate (mean dose 514 mg i.d.) and titrated to a mean dose of 1009 mg i.d. (mean plasma concentration 0.7 mmol/L). Treatment response was assessed by comparing changes in clinical severity scales for mood and eating disorders, weekly binge eating frequency, and weight for the 2 months before and the first 2 months during lithium treatment.

Results

A statistically significant improvement in global severity of mood symptoms was observed after as compared to before lithium augmentation. Statistically insignificant reductions in weight and in binge frequency and severity were also observed after lithium addition.

Conclusion

Optimal weight loss treatment in obese patients with comorbid bipolar and BEDs may require stabilization of mood. The combination of lithium and topiramate may have a role in the management of this difficult‐to‐treat population. Copyright © 2006 John Wiley & Sons, Ltd.
A quantitative study of sediment delivery and stream pollution from different forest road types
Authors: Sheridan Gary J. , Noske Philip J.
Published: August 2006

The objective of this paper is to quantify, and enable the prediction of, sediment delivery and water pollution impacts from a spectrum of forest roads. Ten 100–200 m long sections of forest road were selected to incorporate a wide range of the key physical site factors that are likely to affect the rate of sediment generation. Each road section was permanently instrumented for 1 year to measure rainfall and runoff continuously. Suspended load, bedload, and traffic were integrated measurements over 2‐ to 3‐week site‐service intervals. Total annual sediment load (normalized for slope) varied about 25‐fold, from 216 mg m−2per millimetre of rain for a high‐quality gravel surfaced road with minimal traffic to 5373 mg m−2per millimetre of rain for an unsurfaced road on an erodible subsoil with moderate light‐vehicle traffic. For the seven gravel‐surfaced roads in this study, truck traffic (axles/week) explained 97% of the variation in annual sediment delivery (per unit of rainfall) from the road. Equations are proposed that allow annual sediment delivery rates to be estimated when net rainfall, road slope, road area, and truck traffic are known. Roads produce runoff rapidly and were found to deliver sediment for about the same duration as rainfall is falling, in this study varying between 5 and 10% of the time. The patterns of sediment delivery measured from the experimental roads (frequency, duration, and intensity) in this study are similar to levels that have been shown to alter the composition of in‐stream macroinvertebrate communities in small (e.g. <10 l s−1), clean, mountain streams. However, in larger well‐mixed streams (e.g. >500 l s−1), dilution is sufficient to prevent concentrations reaching critical levels that are likely to result in biological impacts. Copyright © 2006 John Wiley & Sons, Ltd.
Heat treatment of BMP‐2 depots on implant materials generates an immobilized layer of BMP‐2 with pronounced bioactivity
Authors: Winkler Lars , Bingmann Dieter , Wiemann Martin
Published: August 2006

Bone cells seeded directly on depots of bone morphogenetic protein‐2 (BMP‐2) increase alkaline phosphatase (ALP) expression. Heating of such BMP‐2 depots to 100°C augmented the intensity of this local ALP induction. To understand this unexpected finding, we investigated the effect of heat treatment on BMP‐2 depots more closely. Using a novel bioassay based on ALP‐induction of remote cells, we found that the amount of released bioactive BMP‐2 from heat‐treated depots decays within days and could be described by an exponential function. From this function, we expected that pre‐incubation of BMP‐2 depots in culture medium for 4 weeks renders them insufficient to induce ALP. However, preincubated, heat‐treated depots still induced maximal ALP, unless treated with the selective BMP‐2 inhibitor noggin. Furthermore, heat treatment of BMP‐2 depots generated a layer of immunoreactive BMP‐2 at the surface of the carrier. In contrast, BMP‐2 was washed off completely if heat treatment of adsorbed protein was omitted. Results show that heat treatment generates both a soluble pool of BMP‐2 and a material‐bound layer of BMP‐2 in which the protein is protected against degradation. Therefore, heat treatment appears useful to locally immobilize BMP‐2 on various implant surfaces. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Influence of modified extracellular matrices on TI6AL4V implants on binding and release of VEGF
Authors: Wolf‐Brandstetter Cornelia , Lode Anja , Hanke Thomas , Scharnweber Dieter , Worch Hartmut
Published: August 2006

Besides osteoconductive and osteoinductive signals, angiogenesis plays a crucial role in bone development and regeneration and consequently in the integration of implants. Therefore we investigated in this study the binding and release behaviour of vascular endothelial growth factor (VEGF) from Ti6Al4V surfaces coated with 3‐dimensional collageneous matrices, some additionally modified with heparin. The heparin was incorporated using different methods: a) adsorptive immobilization b) crosslinking with N‐(3‐dimethylaminopropyl)‐N′‐ethylcarbodiimide (EDC) or c) incorporating during self‐assembly of fibrils followed by cross‐linking. For unmodified samples, maximum VEGF adsorption was reached with 85 ng VEGF/cm2. On all 3d‐collagen coated surfaces studied (with or without heparin), no saturation could be observed in the range of 0–256 ng VEGF/cm2.

Improved release kinetics were observed for the modified coatings. The initial burst of VEGF within the first 24 h was diminished. From the third day of delivery heparinized matrices showed a higher release of VEGF than the pure collagen matrix and the unmodified reference surface, respectively. In vitro, the proliferation of human dermal microvascular endothelial cells was increased with released VEGF from all investigated samples compared to a VEGF‐free control. After 7 days highest increases in cell numbers were observed with solutions from heparinized matrices.

It is concluded that functionalization of Ti6Al4V surfaces with heparinized collageneous matrices and VEGF leads to advantageous properties concerning the impact on angiogenesis and thus may improve bone regeneration in the microenvironment of implants. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Synthesis and evaluation of injectable, in situ crosslinkable synthetic extracellular matrices for tissue engineering
Authors: Shu Xiao Zheng , Ahmad Shama , Liu Yanchun , Prestwich Glenn D.
Published: August 2006

Simple and effective biocompatible materials that mimic the natural extracellular matrix (ECM) were developed for a variety of uses in regenerative medicine. These synthetic ECMs (sECMs) were designed to recapitulate the minimal composition required to obtain functional ECMs. The sECM components are crosslinkable in situ, and may be seeded with cells prior to injection in vivo, without compromising either the cells or the recipient tissues. Several sECM compositions were evaluated to establish which formulation would be most beneficial for cell growth and tissue remodeling. Three natural ECM macromonomeric building blocks were employed: hyaluronan (HA), chondroitin sulfate (CS), and gelatin (Gtn). The carboxyl‐rich glycosaminoglycans and Gtn were each chemically modified to give the corresponding thiolated dithiopropionylhydrazide (DTPH) derivatives (CS‐DTPH, HA‐DTPH, and Gtn‐DTPH). Different compositions of CS‐Gtn and HA‐Gtn hydrogels were fabricated by crosslinking the thiolated biomacromonomers with polyethylene glycol diacrylate. Each sECM had high water content (>96%), biologically suitable mechanical properties, and a useful gelation time (∼2–6 min). The bioerosion rates for the sECMs were determined, and a given composition could be selected to meet the requirements of a given clinical application. Both the HA‐Gtn and CS‐Gtn sECM hydrogels supported cell growth and proliferation with cultured murine fibroblasts in vitro. Moreover, subcutaneous injection of a suspension of murine fibroblasts in each of the two sECM hydrogels into nude mice in vivo resulted in the formation of viable and uniform soft tissue in vivo. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Heparin‐immobilized biodegradable scaffolds for local and sustained release of angiogenic growth factor
Authors: Yoon Jun Jin , Chung Hyun Jung , Lee Hyuk Jin , Park Tae Gwan
Published: August 2006

Heparin‐immobilized porous biodegradable scaffolds were fabricated to release basic fibroblast growth factor (bFGF) in a sustained manner. Heparin was covalently conjugated onto the surface of macroporous PLGA scaffolds fabricated by a gas‐foaming/salt‐leaching method. Sustained release of bFGF was successfully achieved for over 20 days due to high affinity of bFGF onto the immobilized heparin. It appears that bFGF release rate was regulated by the specific interaction between bFGF and heparin. The bFGF fraction released from the scaffolds maintained its bioactivity, as judged from determining the proliferation extent of human umbilical vein endothelial cells (HUVECs) in vitro. When heparin‐immobilized scaffolds loaded with bFGF were implanted subcutaneously in vivo, they effectively induced the formation of blood vessels in the vicinity of the implant site. This study demonstrated that local and sustained delivery of angiogenic growth factor for tissue regeneration could be achieved by surface modification of porous scaffolds with heparin. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Diffusion of bioactive molecules through the walls of the medial tissue‐engineered hybrid ePTFE grafts for applications in designs of vascular tissue regeneration
Authors: Noh Insup , Choi Yoon‐Jeong , Son Youngsook , Kim Chun‐Ho , Hong Seung‐Hwa , Hong Choong‐Man , Shin In‐Soo , Park Sue‐Nie , Park Beom‐Young
Published: August 2006

Strategies of better vascular tissue engineering may require delivery of soluble bioactive signals in cell culture medium to the cells in tissue‐regenerating constructs. We measured the diffusivity and permeability of model tissue‐engineering bioactive molecules such as water and heparin through the walls of both a hybrid ePTFE graft and a porcine carotid artery, a model vascular tissue. While diffusivities of H3‐water and H3‐heparin were measured as 3.9 × 10−6 and 1.6 × 10−6 cm2/s in the artery, respectively, under diffusional circulation of cell culture medium through the lumens of the carotid arteries, their corresponding permeabilities were 4.7 × 10−5 and 2.0 × 10−5 cm/s. On the other hand, diffusivities of H3‐water and H3‐heparin were also measured as 5.1 × 10−6 and 4.7 × 10−6 cm2/s, respectively, in the tissue‐engineered hybrid ePTFE grafts; their corresponding permeabilities were 5.1 × 10−5 and 3.7 × 10−5 cm/s. The hybrid graft tissues were engineered by replacing the biodegradable, porous poly(lactide‐co‐glycolide) layers coated on the ePTFE surfaces with smooth muscle cell‐derived tissues for 6 weeks. We analyzed the morphologies of the artery and the engineered hybrid ePTFE tissues with scanning electron microscopy and H&E stains. While the artery had its typical structure properties with layers of intima, media and adventitia, the tissue‐engineered ePTFE hybrid graft had two layers of engineered tissues on the inner and outer surfaces of the ePTFE. There were no significant differences among the luminal tissue morphologies of the test samples from the effects of diffusion flow applications, with minor changes on their luminal surfaces. The results of water and heparin diffusion experiments indicated that these bioactive molecules were well transported from the cell culture medium to the tissue‐engineering cells, enough to support tissue regeneration. We hope that these transport results may elucidate the transport behaviors of soluble nutrient molecules and biological signals through the vascular constructs under tissue engineering processes. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Self‐assembled copper‐capillary alginate gel scaffolds with oligochitosan support embryonic stem cell growth
Authors: Willenberg Bradley J. , Hamazaki Takashi , Meng Fan‐Wei , Terada Naohiro , Batich Christopher
Published: August 2006

Biomaterial scaffolds are fundamental components of strategies aimed at engineering a wide range of tissues. Scaffolds possessing uniform, oriented microtubular architectures could be ideal for multiple tissues, but are challenging to produce. Therefore, we developed hydrogel scaffolds possessing regular, tubular microstructures from self‐assembled copper‐capillary alginate gel (CCAG). To abrogate the rapid dissolution of CCAG in cell culture media, we treated it with oligochitosan and created a stable oligochitosan–CCAG (OCCAG) polyelectrolyte complex. Fourier transform infrared spectroscopy confirmed polyelectrolyte complexation between alginate and oligochitosan. OCCAG retained capillary morphology, shrank anisotropically in bulk, lost Cu2+ ions, and maintained (71.9 ± 5.65)% of its mass in cell culture media. Next, we seeded mouse embryonic stem (ES) cells within OCCAG scaffolds, and examined cell morphology and quantified cell growth and viability over four days. ES cells were guided to form cylindrical structures of staggered cells within scaffold capillaries. Analysis of the total cells recovered from the scaffolds revealed exponential cell growth (normalized to day 0) that was statistically similar to gelatinized‐plate controls. OCCAG‐cultured ES cell viability was also not significantly different from controls at day 4. CCAG‐derived scaffolds can therefore serve as a unique platform for stem cell‐based tissue engineering. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Development and characterization of porous silver‐incorporated hydroxyapatite ceramic for separation and elimination of microorganisms
Authors: Yang Lei , Ning Xiaoshan , Xiao Qunfang , Chen Kexin , Zhou Heping
Published: August 2006

A novel filter material for separating and eliminating microorganisms in water and gas was fabricated by incorporating silver ions into porous hydroxyapatite (HA) ceramics prepared by a starch additive technique. The porous ceramics reveal a microstructure of both large and small pores. Microorganism separating and eliminating properties of the porous silver‐incorporated HA ceramics (PHA‐Ag) were investigated by bacterial and viral filtration tests. The PHA‐Ag demonstrated excellent separating and antibacterial effects on Escherichia coli and the mechanisms were studied. Adsorption of bacterial cells to the HA and the barricading effect of small pores contribute to the separating property of PHA‐Ag, while the Ag+ ions equip the ceramics with antibacterial property. Furthermore, the PHA‐Ag exhibited an observable virus‐eliminating property and its probable mechanism was also discussed. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Microperoxidase primer promotes adhesion of butylborane‐polymerized resin to dentin
Authors: Taira Yohsuke , Soeno Kohyoh , Atsuta Mitsuru
Published: August 2006

The purpose of this study was to investigate the effect of dentin primers containing microperoxidase (MP‐11) with 2‐hydroxyethyl methacrylate (HEMA) on the bond strength between a tri‐n‐butylborane‐initiated self‐polymerizing resin and dentin. Bovine dentin surfaces were etched with 10 wt % phosphoric acid, primed, and then bonded with stainless steel rods. Tensile bond strength after 24 h of storage in water was significantly influenced by both MP‐11 and HEMA. Groups with no MP‐11 showed the lowest values. Without HEMA, the bond strengths of groups using 0.01, 0.1, and 1.0 μmol/g MP‐11 were statistically identical, and also greater than that of the no MP‐11 control. In the presence of HEMA, the bond strength was significantly enhanced with an increasing concentration of MP‐11. The highest bond strength of 29.0 MPa was obtained with aqueous HEMA primer, containing 1.0 μmol/g MP‐11. Microscopic observation showed the formation of a hybrid layer at the bonded interface. Polymerization of the resin was significantly accelerated with the MP‐11 primer. In conclusion, MP‐11 has a potential for adhesive bonding promoter between the resin and the demineralized dentin surface. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Grafting amine‐terminated branched architectures from poly(L‐lactide) film surfaces for improved cell attachment
Authors: Janorkar Amol V. , Fritz Edward W. , Burg Karen J. L. , Metters Andrew T. , Hirt Douglas E.
Published: August 2006

Poly(L‐lactide) (PLL) has been used as a bioabsorbable material in the medical and pharmaceutical fields. The unmodified hydrophobic PLL surface generally has low cell affinity; thus, modification of PLL film surface properties is necessary to improve its use as a biomaterial. Our surface modification method involved the use of photografting and typical wet chemistry to create branched architectures containing amine functionalities on the periphery of the grafted layers. Amine (NH2) groups were first introduced on the PLL film surface by photoinduced grafting of 4,4′‐diaminobenzophenone and the grafted branched architectures were created by subsequent reactions with succinic acid and tris(2‐aminoethyl) amine. The resulting film surface was analyzed using contact angle goniometry and X‐ray photoelectron spectroscopy. MC3T3 fibroblasts were cultured on unmodified PLL film and PLL films grafted with the branched structures and the films were subsequently analyzed by optical microscopy. The contact angle goniometry results showed an initial decrease and subsequent plateau in the water contact angles for the PLL films with each successive generation of the branched architectures. The X‐ray photoelectron spectroscopy data provided insight into the structure of the grafted layer and revealed an increase in the nitrogen content with each generation. Optical micrographs showed enhanced cell attachment and viability on the surface‐modified PLL films. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Unphosphorylated MARCKS is involved in neurite initiation induced by insulin‐like growth factor‐I in SH‐SY5Y cells
Authors: Shiraishi Mitsuya , Tanabe Atsuhiro , Saito Naoaki , Sasaki Yasuharu
Published: August 2006

Myristoylated alanine‐rich C kinase substrate (MARCKS) has been suggested to be involved in various aspects of neuronal cell differentiation, including neurite outgrowth. However, the precise mechanisms by which MARCKS phosphorylation is regulated, and how MARCKS contributes to neurite outgrowth, are poorly understood. Here, we found that treatment of SH‐SY5Y cells with insulin‐like growth factor‐I (IGF‐I) induced a rapid and transient decrease in the level of phosphorylated MARCKS (P‐MARCKS) to below the basal level. The decrease in P‐MARCKS induced by IGF‐I was blocked by pretreatment of cells with phosphoinositide 3‐kinase (PI3K) inhibitors, LY294002 and wortmannin. A decrease in P‐MARCKS was also observed in cells treated with a Rho‐dependent kinase (ROCK) inhibitor, Y27632. Furthermore, IGF‐I induced transient inactivation of RhoA, an upstream effector of ROCK. We showed that MARCKS was translocated to the membrane and colocalized with F‐actin at the lamellipodia and the tips of neurites in the cells stimulated with IGF‐I. Finally, overexpression of wild‐type MARCKS or an unphosphorylatable mutant of MARCKS enhanced the number of neurite‐bearing cells relative to vector‐transfected cells. Taken together, these findings suggest that unphosphorylated MARCKS is involved in neurite initiation, and highlight the important role played by MARCKS in organization of the actin cytoskeleton. J. Cell. Physiol. 209: 1029–1038, 2006. © 2006 Wiley‐Liss, Inc.
Application of microscopic techniques in authentication of herbal tea—Ku‐Ding‐Cha
Authors: Tam Chun‐Fung , Peng Yong , Liang Zhi‐Tao , He Zhen‐Dan , Zhao Zhong‐Zhen
Published: August 2006

Ku‐Ding‐Cha, a kind of herbal tea, has been widely used in China for a long time to support cardiovascular health. Confusion arises because in different parts of China different plants are used to produce the commercial teas. It is important to determine the identity of the used species in order to authenticate genuine Ku‐Ding‐Cha. However, once the plants have been processed, it is difficult to identify them through macroscopic identification; other means are necessary. A comparative study was made on 24 samples of Ku‐Ding‐Cha, including five standard identified and authenticated plants and 19 commercial samples, by microscopic techniques. The results showed that the shapes of leaf blades, xylem cells, stone cells, and calcium oxalate crystals could be used for the identification of the plants from which the commercial products were made. The method was proven to be quick, handy, simple, and convenient. Microsc. Res. Tech., 2006. © 2006 Wiley‐Liss, Inc.
Vasomodulation of skeletal muscle BOLD signal
Authors: Bulte Daniel P. , Alfonsi Jeff , Bells Sonya , Noseworthy Michael D.
Published: August 2006

Purpose

To evaluate whether the BOLD signal from skeletal muscle can be modulated by exercise and ingestion of vasoactive substances.

Materials and Methods

The right calf muscles of healthy adult volunteers were imaged using a GE 1.5‐Tesla scanner and a gradient‐echo sequence with spiral readout. Time‐varying changes in the BOLD signal were induced through cyclic phases of normoxia (90 seconds of 20.8% O2) and hyperoxia (45 seconds of 100% O2 at 22 L/minute). Superimposed on this paradigm were pre‐ and post‐exercise regimes, with and without ingestion of caffeine (100 mg) or antihistamine (4 mg chlorpheniramine). The numbers of voxels within slow‐twitch (soleus) and fast‐twitch (gastrocnemius) muscles that significantly responded to the paradigms were scored and compared using the AFNI software (NIMH).

Results

Cycling‐inspired O2 produced a corresponding BOLD modulation that increased in magnitude with exercise. Chlorpheniramine significantly (P < 0.01) prevented the overall increase in exercise‐induced soleus muscle BOLD signal, while caffeine accentuated the increase (P < 0.05) in the gastrocnemius relative to control (no vasomodulator) conditions.

Conclusion

BOLD signal changes with exercise can be modulated by standard doses of chlorpheniramine (antihis‐tamine) and caffeine. We suggest that chlorpheniramine may act detrimentally on slow‐twitch muscle contractility, while caffeine appears to improve fast‐twitch muscle function. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Laser desorption/ionization techniques in the characterization of high molecular weight oil fractions. Part 1: asphaltenes
Authors: Rizzi Andrea , Cosmina Paola , Flego Cristina , Montanari Luciano , Seraglia Roberta , Traldi Pietro
Published: August 2006

The molecular weight distribution of the asphaltene fractions of two types of crude oils from two different Italian fields (samples 1 and 2) was investigated. The analytical tools used to perform these analyses were matrix assisted laser desorption ionization (MALDI) and laser desorption ionization (LDI) mass spectrometry. After observing that the use of the matrix (as well as the addition of Ag+) did not improve the quality of the data compared to that obtained in LDI conditions, all further measurements were performed with the latter technique. Operating under usual conditions of laser power and delay time, a very low resolution was observed, showing only macroscopic differences between the two samples in the molecular weight distribution of the different components. An accurate study on the possible reasons of this undesirable behavior indicates that it can originate from space charge phenomena occurring either in the ion source region or during the flight. A valid parameterization of the delay time and the laser power allowed higher quality spectra to be obtained. Surface‐enhanced laser desorption ionization (SELDI) measurements were also performed using normal phase (silica) as the sample holder surface. Under these conditions, better results are obtained, proving that the sample–surface interaction is important to achieve, by means of laser irradiation, a homogeneous set of product ions. Both asphaltene samples were fractionated in five subfractions by gel‐permeation chromatography (GPC) to obtain a better separation of the molecular weight distributions; the related spectra confirmed these findings. By using different approaches, relevant and reproducible differences between the asphaltene fractions of the two oil samples were observed. Copyright © 2006 John Wiley & Sons, Ltd.
Lactacystin decreases amyloid‐β peptide production by inhibiting β‐secretase activity
Authors: Kienlen‐Campard Pascal , Feyt Christine , Huysseune Sandra , de Diesbach Philippe , N'Kuli Francisca , Courtoy Pierre J. , Octave Jean‐Noël
Published: August 2006

The human amyloid precursor protein (APP) is processed by the nonamyloidogenic and the amyloidogenic catabolic pathways. The sequential cleavage of APP by the β‐ and γ‐secretase activities, known as the amyloidogenic processing of APP, leads to the formation of the amyloid‐β peptide (Aβ). Aβ is the main constituent of the amyloid core of senile plaques, a typical hallmark of Alzheimer's disease. In addition to secretases, other cellular proteolytic activities, like the proteasome, might participate in the metabolism of APP. We investigated the consequence of proteasome inhibition on the amyloidogenic processing of human APP. CHO cells and primary cultures of rat cortical neurons expressing human APP or a protein corresponding to its β‐cleaved C‐terminal fragment (C99) were treated with lactacystin, an irreversible inhibitor of the chymotrypsin‐like activity of the proteasome. Lactacystin significantly decreased the level of Aβ produced from APP in both cellular models, whereas the production of Aβ from C99 was not affected. Lactacystin did not inhibit γ‐secretase activity but was found to inhibit the β‐cleavage of APP, leading to a proportional decrease in Aβ production. Although lactacystin did not inhibit the catalytic activity of recombinant BACE1, a decrease in neuronal β‐secretase activity was measured after treatment with lactacystin. © 2006 Wiley‐Liss, Inc.
Unaltered neuropeptide Y (NPY)‐stimulated [35S]GTPγS binding suggests a net increase in NPY signalling after repeated electroconvulsive seizures in mice
Authors: Christensen D.Z. , Olesen M.V. , Kristiansen H. , Mikkelsen J.D. , Woldbye D.P.D.
Published: August 2006

Although electroconvulsive seizures (ECS) are widely used as a treatment for severe depression, the working mechanism of ECS remains unclear. Repeated ECS causes anticonvulsant effects that have been proposed to underlie the therapeutic effect of ECS, and neuropeptide Y (NPY) is a potential candidate for mediating this anticonvulsant effect. Repeated ECS results in prominent increases in NPY synthesis. In contrast, NPY‐sensitive receptor binding is decreased, so it is unclear whether ECS causes a net increase in NPY signalling. Agonist‐stimulated [35S]GTPγS binding is a method for detecting functional activation of G‐protein‐coupled receptors. The present study in mice examined the effects of daily ECS for 14 days on NPY‐stimulated [35S]GTPγS functional binding and compared this with gene expression of NPY and NPY receptors as well as [125I]peptide YY (PYY) binding in hippocampus of the same animals. Significant increases in NPY mRNA and concomitant reductions in NPY‐sensitive binding were found in the dentate gyrus, hippocampal CA1, and neocortex of ECS treated mice, which is consistent with previous rat data. These changes remained significant 1 week after repeated ECS. Significant increases in NPY Y1, Y2, and Y5 mRNA were found in the dentate gyrus after ECS. Surprisingly, unaltered levels of functional NPY receptor binding accompanied the decreased NPY‐sensitive binding. This suggests that mechanisms coupling NPY receptor stimulation to G‐protein activation could be augmented after repeated ECS. Thus increased synthesis of NPY after repeated ECS should result in a net increase in NPY signalling in spite of reduced levels of NPY‐sensitive binding. © 2006 Wiley‐Liss, Inc.
Phagocytosis of apoptotic inflammatory cells downregulates microglial chemoattractive function and migration of encephalitogenic T cells
Authors: Chan Andrew , Hummel Vera , Weilbach Franz X. , Kieseier Bernd C. , Gold Ralf
Published: August 2006

Apoptosis of autoaggressive T cells in the central nervous system (CNS) and subsequent phagocytosis by microglia is probably crucial in the rapid resolution of the inflammatory infiltrate in T cell mediated neuroinflammatory diseases. In addition to mere clearance, phagocytosis of apoptotic leukocytes results in the downregulation of different microglial immune functions. Chemoattractive functions of Lewis rat microglia and secretion of chemokines and matrix‐metalloproteinases (MMPs) were investigated after phagocytosis of apoptotic T cells in vitro. In a modified Boyden chamber assay migration of encephalitogenic T cells toward LPS‐stimulated microglial supernatants after phagocytosis of apoptotic thymocytes was reduced by 24.9% in comparison to interaction with viable target cells (P < 0.001). Phagocytosis of apoptotic cells downregulated CC‐chemokine ligand (CCL)‐5‐secretion by LPS‐stimulated microglia by 66.2% (P < 0.001), whereas there was only a trend toward decreased CCL2‐secretion. As determined by gelatinase‐zymography, secretion of MMP‐9 by microglia was decreased after phagocytosis of apoptotic cells, whereas MMP‐2 secretion was not altered. These mechanisms may reduce further recruitment of pathogenic inflammatory cells into the CNS‐lesion and thus contribute to the active resolution of the inflammatory infiltrate and termination of the autoimmune attack. © 2006 Wiley‐Liss, Inc.
Knockdown of uncoupling protein‐5 in neuronal SH‐SY5Y cells: Effects on MPP+‐induced mitochondrial membrane depolarization, ATP deficiency, and oxidative cytotoxicity
Authors: Ho Philip Wing‐Lok , Chu Andrew Chi‐Yuen , Kwok Ken Hon‐Hung , Kung Michelle Hiu‐Wai , Ramsden David Boyer , Ho Shu‐Leong
Published: August 2006

Uncoupling proteins (UCPs) uncouple oxidative phosphorylation from ATP synthesis by dissipating proton gradient across mitochondrial inner membrane. The physiological role of neuronal specific UCP5 is unknown. We explored the effects of reduced UCP5 expression on mitochondrial membrane potential (MMP), oxidative stress, ATP levels, and cell viability, under normal and MPP+‐induced cytotoxic conditions, in human catecholaminergic SH‐SY5Y cells. UCP5 expression was reduced by 56% by siRNA, compared to scrambled‐siRNA controls. UCP5 knockdown induced apoptosis but did not affect basal levels of ATP, oxidative stress and MMP in the cells under normal conditions. However, UCP5 knockdown increased MPP+‐induced cytotoxicity by 15% and oxidative stress levels by 40%, and partially restored MPP+‐induced mitochondrial depolarization by 57%. UCP2 and UCP4 expression were unaffected by UCP5 knockdown. Exacerbation of cytotoxicity, oxidative stress and modification of MMP with reduced UCP5 expression in the face of MPP+ toxicity suggest that UCP5 might be physiologically important in the pathology of oxidative stress‐induced neurodegeneration. © 2006 Wiley‐Liss, Inc.
Raman scattering investigations of the low‐temperature phase transition of NaNbO3
Authors: Lin S. J. , Chiang D. P. , Chen Y. F. , Peng C. H. , Liu H. T. , Mei J. K. , Tse W. S. , Tsai T.‐R. , Chiang H.‐P.
Published: August 2006

In this work, we report the low‐temperature phase transition of sodium niobate (NaNbO3) ceramics at the antiferroelectric–ferroelectric phase studied by the Raman scattering technique over the temperature range 10–300 K. The spectral shape indicates that the phase transition occurs at 160 K on the cooling cycle and at 260 K on heating. The recorded spectra are discussed following the separation of modes into the internal stretching modes of the NbO6 octahedron and Na+ cation translational modes. The 62 and 75 cm−1 peaks are proposed as the translational modes of Na+ cation against the NbO6 octahedron. Copyright © 2006 John Wiley & Sons, Ltd.
The effect of applied tensile stress on the exfoliation corrosion of 7075‐T6 alloy
Authors: Su J. , Zhang Z. , Shi Y. , Yang Z. , Zhang J. , Cao C.
Published: August 2006

The effect of the applied tensile stress on the exfoliation corrosion of 7075‐T6 alloy in EXCO solution has been studied. Electrochemistry Impedance Spectroscopy (EIS), Scanning Electron Microscope (SEM) and optical microscope techniques were used to characterize the initiation and propagation of the exfoliation corrosion (EC) under different applied tensile stress levels. Two equivalent circuit models were developed to fit the EIS data of the initiation and propagation stages of EC according to their corresponding physicochemical properties respectively. The correlation between the characteristics of EIS evolution and the localized corrosion types was established, and a new criteria for detecting the initiation of EC of aluminum alloys was brought forward. The results also showed that the tensile stress accelerates EC by increasing the number of the active sites during its initiation stage.
The cavitation erosion and erosion‐corrosion behavior of carbon steel in simulating solutions of three rivers of China
Authors: Yu H. , Zheng Y. G. , Yao Z. M.
Published: August 2006

The corrosion behaviour of the Q235 carbon steel in simulation solution of Yangtze, Yellow and Talimu river of China was investigated by mass loss, electrochemical measurements (polarization curves, linear polarization resistance and electrochemical impedance spectroscopy) and the damaged surfaces were observed by a scanning electron microscope (SEM) under static, cavitation erosion and erosion‐corrosion conditions. It was shown that under static condition, the Ecorr was almost the same in the three solutions but the anodic current density in Talimu river was about one order of magnitude larger than that in Yangtze and Yellow river. Under dynamic conditions including cavitation erosion and erosion‐corrosion, the Ecorr in the three solutions all shifted in positive direction from that under static condition, but the extent of ΔEcorr increased in the order of Yangtze, Yellow and Talimu river. The corrosion rate under dynamic conditions greatly enhanced, especially in Talimu river. It was confirmed that the corrosion played an important role in the synergistic effect under cavitation erosion and erosion‐corrosion conditions. The test results suggested that when the structure materials used in the different rivers were chosen, the difference of corrosiveness of the rivers must be taken into account, especially under dynamic conditions. The materials used in the aggressive rivers such as Talimu river under dynamic conditions must resist the synergistic effects between erosion and corrosion.
Evolution of a Metallocenic sPP with Time: Changes in Crystalline Content and Enthalpic Relaxation
Authors: Arranz‐Andrés Javier , Benavente Rosario , Ribeiro M. Rosário , Pérez Ernesto , Cerrada Maria L.
Published: August 2006

Summary: The structural evolution of a metallocenic syndiotactic poly(propylene), sPP, with time has been studied. Due to the low syndiotactic content, the analyzed sPP sample can be easily quenched to a completely amorphous state. This amorphous sample, when left at room temperature is able to crystallize at relatively long times. The degree of crystallinity, as a function of time, has been analyzed by X‐ray diffraction and DSC. The DSC melting curves show the presence of a very important low‐temperature endotherm, besides the main melting peak. Real‐time variable–temperature synchrotron experiments have been performed in order to analyze the origin of the two melting peaks. They seem to arise from the melting of two populations of sPP crystals with different size and/or perfection, rather than from the melting of different polymorphs. The changes in the crystalline regions are accompanied by important variations in the mechanical behavior, as revealed by DMTA and microhardness (MH) measurements. In addition, the sPP crystallization has been analyzed by MH measurements, showing the importance that a relative low crystallinity has on the stiffness of a polymeric material at temperatures above Tg. On the other hand, the kinetics of the enthalpic recovery of quenched amorphous sPP specimens has been analyzed by DSC with temperature modulation. It was found that this enthalpic relaxation can be described by the KWW model, and the relaxation times and shape parameters at three different aging temperatures have been determined, with the corresponding apparent activation energy of this process.

Variation with temperature of the most probable long spacing of sPP.

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Variation with temperature of the most probable long spacing of sPP.
New Siloxane‐Organic Polyesters with Azobenzene Side Chains. Synthesis, Thermotropic Behavior and Surface Properties
Authors: Racles Carmen , Filip Daniela , Cazacu Maria , Cozan Vasile , Tóth András , Ioanid Ghiocel
Published: August 2006

Summary: New siloxane‐organic polyesters, bearing azo‐type units in the side chain, were synthesized by direct solution polycondensation at room temperature, starting from 2,2′‐[4‐[(4‐nitrophenyl)azo]phenyl]iminobisethanol (Disperse Red 19) and different siloxane diacids, using dicyclohexylcarbodiimide as an activator and 4‐(N,N‐dimethylamino)pyridinium‐p‐toluenesulfonate as the catalyst. The structure of the obtained polyesters was confirmed by 1H and 13C NMR as well as IR spectroscopy. The molecular weight and polydispersity were estimated by GPC. The thermotropic behavior was investigated by POM, DSC and TOA. The surface composition was determined by ESCA (XPS) analysis and proved enrichment in silicon for all samples. All compounds show good solubility in common organic solvents.

An example of a nitroazobenzene‐containing side‐chain polyester with various siloxane‐organic backbones.

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An example of a nitroazobenzene‐containing side‐chain polyester with various siloxane‐organic backbones.
NMR Microscopy: A Tool for Measuring Monomer Diffusion in Supercritical CO2
Authors: Thurecht Kristofer J. , Hill David J. T. , Whittaker Andrew K.
Published: August 2006

Summary: The diffusion of styrene into linear low density polyethylene in a solution of supercritical CO2 was investigated using NMR microimaging. For both pure styrene and styrene dissolved in supercritical CO2, the diffusion was found to follow Fickian kinetics. Supercritical CO2 was found to enhance the rate and extent of diffusion of styrene into the substrate by up to three times under the conditions of this investigation, compared to pure styrene. NMR imaging was used to measure the concentration profiles of the styrene penetrants in real time, and the results were fitted to a Fickian model for diffusion. At a CO2 pressure of 150 bar and temperature of 40 °C, the diffusion coefficient of a 30 wt‐% solution of styrene into LLDPE was calculated to be 1 × 10−11 m2 · s−1. This is significantly faster than the diffusion coefficient measured for pure styrene diffusion at 40 °C (3 × 10−12 m2 · s−1). The diffusion coefficients determined by gravimetric analysis were slightly higher than those determined by the imaging method. This was probably due to residual styrene and/or polystyrene adhering to the surface of the films in the gravimetric technique.

NMR image of styrene in linear low density polyethylene following supercritical fluid enhanced impregnation.

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NMR image of styrene in linear low density polyethylene following supercritical fluid enhanced impregnation.
New electronic scanning traveling‐wave antenna array
Authors: Alaeddine A. , Rammal M. , Bazzi O. , Mohanna Y. , Reineix A.
Published: August 2006

A plan traveling‐wave array to realize an electronic scanning antenna is described. A theoretical analysis of the microstrip antenna and experimental results of the series‐fed element array are presented. An efficient synthesis method is used to produce the desired radiated patterns like side lobes and high gain. Eight elements of the linear traveling‐wave series‐fed array were used and tested. High performance and good gain have been observed over a relatively large band. For a frequency shift of 100 GHz, the lobe scanned 2°. This array promises to be a candidate in an electronic scanning antenna. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2186–2189, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21882
Double‐ridged horn antenna for millimeter‐wave applications
Authors: Moon Jung‐Ick , Yun Jae‐Hoon
Published: August 2006

This study presents a broadband double‐ridged horn antenna for millimeter‐wave applications. The proposed broadband antenna has a bandwidth of 12.1–63.2 GHz and peak radiation gain of 12.1–19.8 dBi. The performance of this antenna is verified by the measured results and is in good agreement with the simulated results. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2165–2167, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21884
A novel bandpass filter using a dual‐mode square patch resonator with combined CPW and microstrip input/output
Authors: Bo Y. M. , Huang X. D. , Cheng C. H.
Published: August 2006

A novel bandpass filter using a dual‐mode square‐patch resonator is proposed in this article. The input and the output of the filter are constructed on a coplanar‐waveguide (CPW) and a microstrip line, respectively. Therefore, a transition of CPW/microstrip may be simultaneously realized by using the filter. The filter has been investigated numerically and experimentally. Results show that the minimum insertion loss in the passband of the filter is about 2.1 dB and its out‐of‐band rejection level is below −23 dB. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2184–2186, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21885