bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced tight junction function in human breast cancer cells by antioxidant, selenium and polyunsaturated lipid
Authors: Martin Tracey A. , Das Tapas , Mansel Robert E. , Jiang Wen G.
Published: January 2007

Paracellular permeability (PCP) is governed by tight junctions (TJs) in epithelial cells, acting as cell–cell adhesion structures, the aberration of which is known to be linked to the dissociation and metastasis of breast cancer cells. This study hypothesized that the function of TJs in human breast cancer cells can be augmented by gamma linolenic acid (GLA), selenium (Se), and iodine (I) in the presence of 17‐β‐estradiol, as these molecules are known to increase TJ functions in endothelial cells, using assays of trans‐epithelial resistance (TER), PCP, immunofluorescence, and in vitro invasion and motility models. GLA, I, and Se individually increased TER of MDA‐MB‐231 and MCF‐7 human breast cancer cells. The combination of all three agents also had a significant increase in TER. Addition of GLA/Se/I reduced PCP of both breast cancer cell lines. GLA/Se/I reversed the effect of 17‐β‐estradiol (reduced TER, increased PCP). Immunofluorescence revealed that after treatment with Se/I/GLA over 24 h, there was increasing relocation to breast cancer cell–cell junctions of occludin and ZO‐1 in MCF‐7 cells. Moreover, treatment with GLA/Se/I, alone or in combination, significantly reduced in vitro invasion of MDA‐MB‐231 cells through an endothelial cell barrier (P < 0.0001) and reduced 17‐β‐estradiol induced breast cancer cell motility (P < 0.0001). Our previous work has demonstrated that GLA, I, and Se alone, or in combination are able to strengthen the function of TJs in human endothelial cells; this has now proved to be true of human breast cancer cells. This combination also completely reversed the effect of 17‐β‐estradiol in these cells. J. Cell. Biochem. 101: 155–166, 2007. © 2007 Wiley‐Liss, Inc.
L‐type calcium channels in growth plate chondrocytes participate in endochondral ossification
Authors: Mancilla Edna E. , Galindo Mario , Fertilio Barbara , Herrera Mario , Salas Karime , Gatica Hector , Goecke Annelise
Published: January 2007

Longitudinal bone growth occurs by a process called endochondral ossification that includes chondrocyte proliferation, differentiation, and apoptosis. Recent studies have suggested a regulatory role for intracellular Ca2+ (Ca) in this process. Indirect studies, using Ca2+ channel blockers and measurement of Ca, have provided evidence for the existence of Ca2+ channels in growth plate chondrocytes. Furthermore, voltage‐gated Ca2+ channels (VGCC), and specifically L‐ and T‐type VGCCs, have been recently described in murine embryonic growth plates. Our aim was to assess the effect of L‐type Ca2+ channel blockers on endochondral ossification in an organ culture. We used cultures of fetal rat metatarsal rudiments at 20 days post gestational age, with the addition of the L‐type Ca2+ channel blockers verapamil (10–100 µM) or diltiazem (10–200 µM) to the culture medium. Longitudinal bone growth, chondrocyte differentiation (number of hypertrophic chondrocytes), and cell proliferation (incorporation of tritiated thymidine) were measured. Verapamil dose‐dependently decreased growth, the number of hypertrophic chondrocytes, and cell proliferation, at concentrations of 10–100 µM. Growth and the number of hypertrophic chondrocytes decreased significantly with diltiazem at 50–100 µM, and proliferation decreased significantly at concentrations of 10–200 µM. Additionally, there was no increase in apoptosis over physiological levels with either drug. We confirmed the presence of L‐type VGCCs in rat rudiments using immunohistochemistry, and showed that the antagonists did not alter the pattern of VGCC expression. In conclusion, our data suggest that L‐type Ca2+ channel activity in growth plate chondrocytes is necessary for normal longitudinal growth, participating in chondrocyte proliferation and differentiation. J. Cell. Biochem. 101: 389–398, 2007. © 2007 Wiley‐Liss, Inc.
Mechanisms of metastasis: Epithelial‐to‐mesenchymal transition and contribution of tumor microenvironment
Authors: Tse Joyce C. , Kalluri Raghu
Published: January 2007

Every year about 500,000 people in the United States die as a result of cancer. Among them, 90% exhibit systemic disease with metastasis. Considering this high rate of incidence and mortality, it is critical to understand the mechanisms behind metastasis and identify new targets for therapy. In recent years, two broad mechanisms for metastasis have received significant attention: epithelial‐to‐mesenchymal transition (EMT) and tumor microenvironment interactions. EMT is believed to be a major mechanism by which cancer cells become migratory and invasive. Various cancer cells—both in vivo and in vitro—demonstrate features of epithelial‐to‐mesenchymal‐like transition. In addition, many steps of metastasis are influenced by host contributions from the tumor microenvironment, which help determine the course and severity of metastasis. Here we evaluate the diverse mechanisms of EMT and tumor microenvironment interactions in the progression of cancer, and construct a rational argument for targeting these pathways to control metastasis. J. Cell. Biochem. 101: 816–829, 2007. © 2007 Wiley‐Liss, Inc.
Effects of quercetin and quercetin 3‐glucuronide on the expression of bone sialoprotein gene
Authors: Kim Dong‐Soon , Takai Hideki , Arai Masato , Araki Shouta , Mezawa Masaru , Kawai Yoshichika , Murota Kaeko , Terao Junji , Ogata Yorimasa
Published: January 2007

Quercetin is a typical flavonol‐type flavonoid and is present in a variety of vegetables, and their antioxidant effect implies their possible role in the prevention of oxidative stress related chronic diseases. Bone sialoprotein (BSP) is a noncollagenous protein of the extracellular matrix in the mineralized connective tissues that has been implicated in the nucleation of hydroxyapatite crystals. Previously, we reported that isoflavone (genistein) activated BSP gene transcription is mediated through an inverted CCAAT box in the proximal BSP gene promoter. The present study investigates the regulation of BSP transcription in a rat osteoblast‐like cell line, ROS 17/2.8 cells, by quercetin and its conjugated metabolite quercetin 3‐glucuronide. Quercetin and quercetin 3‐glucuronide (5 µM) increased the BSP mRNA levels at 12 h and quercetin upregulated the Cbfa1/Runx2 mRNA expression at 12 h. From transient transfection assays using various sized BSP promoter‐luciferase constructs, quercetin increased the luciferase activity of the construct (pLUC3), including the promoter sequence nucleotides −116 to −43. Transcriptional stimulations by quercetin were almost completely abrogated in the constructs that included 2 bp mutations in the inverted CCAAT and FRE elements whereas the CCAAT‐protein complex did not change after stimulation by quercetin according to gel shift assays. Quercetin increased the nuclear protein binding to the FRE and 3′‐FRE. These data suggest that quercetin and quercetin 3‐glucuronide increased the BSP mRNA expression, and that the inverted CCAAT and FRE elements in the promoter of the BSP gene are required for quercetin induced BSP transcription. J. Cell. Biochem. 101: 790–800, 2007. © 2007 Wiley‐Liss, Inc.
Metabolic syndrome and mitochondrial function: Molecular replacement and antioxidant supplements to prevent membrane peroxidation and restore mitochondrial function
Authors: Nicolson Garth L.
Published: January 2007

Metabolic syndrome consists of a cluster of metabolic conditions, such as hypertriglyeridemia, hyper‐low‐density lipoproteins, hypo‐high‐density lipoproteins, insulin resistance, abnormal glucose tolerance and hypertension, that—in combination with genetic susceptibility and abdominal obesity—are risk factors for type 2 diabetes, vascular inflammation, atherosclerosis, and renal, liver and heart disease. One of the defects in metabolic syndrome and its associated diseases is excess cellular oxidative stress (mediated by reactive oxygen and nitrogen species, ROS/RNS) and oxidative damage to mitochondrial components, resulting in reduced efficiency of the electron transport chain. Recent evidence indicates that reduced mitochondrial function caused by ROS/RNS membrane oxidation is related to fatigue, a common complaint of MS patients. Lipid replacement therapy (LRT) administered as a nutritional supplement with antioxidants can prevent excess oxidative membrane damage, restore mitochondrial and other cellular membrane functions and reduce fatigue. Recent clinical trials have shown the benefit of LRT plus antioxidants in restoring mitochondrial electron transport function and reducing moderate to severe chronic fatigue. Thus LRT plus antioxidant supplements should be considered for metabolic syndrome patients who suffer to various degrees from fatigue. J. Cell. Biochem. 100: 1352–1369, 2007. © 2007 Wiley‐Liss, Inc.
Rapid preparation of [11C]flumazenil: captive solvent synthesis combined with purification by analytical sized columns
Authors: Cleij Marcel C. , Clark John C. , Baron Jean‐Claude , Aigbirhio Franklin I.
Published: January 2007

To produce the radioligand [N‐methyl‐11C]flumazenil at very high specific radioactivity for our small animal imaging studies we have developed procedures for its rapid synthesis, purification and analysis. We have developed ‘micro‐reactor’ apparatus which are assembled from analytical HPLC guard columns packed with stainless steel powder for performing the carbon‐11 methylation reactions. These highly efficient reaction columns enable high radiochemical yields to be obtained with very small amounts of precursor (20–40 µg). The very small amount of reactants used enables the use of small analytical‐sized HPLC columns for the rapid purification of the radioligand. Combining these techniques has enabled us to consistently prepare [N‐methyl‐11C]flumazenil from [11C]iodomethane with radiochemical yields of 80% (decay corrected). This results in 8–10 GBq of [N‐methyl‐11C]flumazenil at very high specific radioactivities of 520–600 GBq/µmol at the end‐of‐synthesis. The total preparation time from end‐of‐bombardment of cyclotron‐produced [11C]carbon dioxide to end‐of‐synthesis is 20 min. A quality control method based on very rapid HPLC analysis (completed within 2 min) on a micro‐analytical HPLC column has also being developed to reduce the time from the end‐of‐synthesis to injection for imaging. Copyright © 2007 John Wiley & Sons, Ltd.
Technetium‐99m labeling and freeze‐dried kit formulation of levofloxacin (L‐Flox): a novel agent for detecting sites of infection
Authors: El‐ghany E. A. , Amin A. M. , El‐kawy O. A. , Amin Magdy
Published: January 2007

In this study, the labeling method of levofloxacin with technetium‐99m and its biological evaluation were described. 99mTc‐L‐Flox was synthesized via direct complexation with technetium‐99m in the presence of stannous chloride dihydrate as reducing agent. The optimum amounts of the reactants are: 1–2 mg levofloxacin, 150 µg stannous chloride dihydrate and 48–1490 MBq pertechnetate. The reaction mixture was bring to pH 6 and kept at room temperature for 30 min. The labeled levofloxacin was stable for more than 8 h. The in vivo evaluation of 99mTc‐L‐Flox in man‐induced inflammation models showed that this tracer was localized with different values. The live E. Coli model had the highest value which was 2.9%, the heat killed E. coli model had a value of 2.0%, and the turpentine oil model had a value of 1.2% at 24 post injection, while the non‐inflamed muscle had activity of 0.5%. All the gathered biological data support the usefulness of 99mTc‐L‐Flox as infection imaging agent. The freeze‐dried form of Sn‐L‐Flox was prepared and found meet all the radiochemical and biological tests. Copyright © 2007 John Wiley & Sons, Ltd.
Inter‐laboratory comparison of elemental analysis and gas chromatography combustion isotope ratio mass spectrometry (GC‐C‐IRMS). Part I: δ13C measurements of selected compounds for the development of an isotopic Grob‐test
Authors: Serra F. , Janeiro A. , Calderone G. , Rojas J. M. Moreno , Rhodes C. , Gonthier L. A. , Martin F. , Lees M. , Mosandl A. , Sewenig S. , Hener U. , Henriques B. , Ramalho L. , Reniero F. , Teixeira A. J. , Guillou C.
Published: January 2007

This study was directed towards investigating suitable compounds to be used as stable isotope reference materials for gas chromatography combustion isotope ratio mass spectrometry (GC‐C‐IRMS) calibration. Several compounds were selected from those used in the ‘Grob‐test’ mixture. Oxygen‐ and nitrogen‐containing substances were added to these compounds to allow the mixture to be used as a possible multi‐isotopic calibration tool for 2H/1H, 13C/12C, 15N/14N and 18O/16O ratio determinations. In this paper we present the results of δ13C measurements performed by the consortium of the five laboratories taking part in this inter‐calibration exercise. All the compounds were individually assessed for homogeneity, short‐term stability and long‐term stability by means of EA‐IRMS, as required by the bureau communitaire de reference (BCR) Guide for Production of Certified Reference Materials. The results were compared then with the GC‐C‐IRMS measurements using both polar and non‐polar columns, and the final mixture of selected compounds underwent a further certification exercise assessing limits of accuracy and reproducibility under specified GC‐C‐IRMS conditions. Copyright © 2007 John Wiley & Sons, Ltd.
Conventional kinesin‐I motors participate in the anterograde axonal transport of neurotrophins in the visual system
Authors: Butowt Rafal , von Bartheld Christopher S.
Published: January 2007

Retinal ganglion cells (RGCs) anterogradely transport neurotrophins to the midbrain tectum/superior colliculus with significant downstream effects. The molecular mechanism of this type of axonal transport of neurotrophins is not well characterized. We identified kinesin‐I proteins as a motor participating in the anterograde axonal movement of vesicular structures containing radiolabeled neurotrophins along the optic nerve. RT‐PCR analysis of purified murine RGCs showed that adult RGCs express all known members of the kinesin‐I family. After intraocular injection of 125I‐brain‐derived neurotrophic factor (BDNF) into the adult mouse or 125I‐neurotrophin‐3 (NT‐3) into the embryonic chicken eye, radioactivity was efficiently immunoprecipitated from the optic nerve lysates by anti‐kinesin heavy chain and anti‐kinesin light chain monoclonal antibodies (H2 and L1). Immunoreactivity for the BDNF receptor trkB is also present in the immunoprecipitates obtained by the anti‐kinesin‐I antibodies. The delivery of the H2 antibody in vivo into the mouse RGCs substantially reduced anterograde axonal transport of 125I‐BDNF. Anterograde transport of BDNF was not diminished in kinesin light chain 1 (KLC1) knockout mice. However, this may be due to redundancy in functions between two different isoforms of KLC present in the RGCs, as it was described previously for kinesin heavy chains (Kanai et al. [ 2000] J Neurosci 20:6374–6384). These data indicate that kinesin‐I is a protein motor that participates in the anterograde axonal transport of neurotrophins in the chicken and mouse visual pathways. © 2007 Wiley‐Liss, Inc.
VEGF‐overexpressing transgenic mice show enhanced post‐ischemic neurogenesis and neuromigration
Authors: Wang Yaoming , Jin Kunlin , Mao Xiao Ou , Xie Lin , Banwait Surita , Marti Hugo H. , Greenberg David A.
Published: January 2007

New neurons are generated continuously in the subventricular zone and dentate gyrus of the adult brain. Neuropathologic processes, including cerebral ischemia, can enhance neurogenesis, as can growth factors and other physiologic stimuli. Vascular endothelial growth factor (VEGF) is an angiogenic and neuroprotective growth factor that can promote neurogenesis, but it is unknown whether VEGF can enhance migration of newborn neurons toward sites of ischemic injury, where they might be able to replace neurons that undergo ischemic death. In the present study we produced permanent focal cerebral ischemia in transgenic (Tg) mice that overexpress VEGF. Cell proliferation and neurogenesis were assessed with bromodeoxyuridine (Brdu) labeling and immunostaining for cell type‐specific markers. In VEGF‐Tg mice, brains examined 7–28 days after cerebral ischemia showed markedly increased subventricular zone (SVZ) neurogenesis, chains of neuroblasts extending from the SVZ to the peri‐infarct cortex, and an increase in the number of newly generated cortical neurons at 14–28 days after ischemia. In concert with these effects, VEGF overexpression reduced infarct volume and improved postischemic motor function. These findings provide evidence that VEGF increases SVZ neurogenesis and neuromigration, consistent with a possible role in repair. Our data suggest that in addition to its neuroprotective effects, which are associated with improved outcome in the acute phase after cerebral ischemia, VEGF enhances postischemic neurogenesis, which could provide a therapeutic target for more chronic brain repair. © 2007 Wiley‐Liss, Inc.
Analyses of representative biomarkers of exposure and effect by chromatographic, mass spectrometric, and nuclear magnetic resonance techniques: Method development and application in life sciences
Authors: Orhan Hilmi
Published: January 2007

Biomarkers are essential tools in monitoring studies, which include environmental monitoring, biological monitoring, biological effect monitoring, and health surveillance, as well as drug development processes. Their discovery, validation, and analysis require highly sensitive and selective analytical technologies. In this regard, gas and liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectroscopy have facilitated great achievements in all these areas. In addition and closely related to biomarkers, the ongoing developments in these techniques promise a better understanding of the nature and mechanisms of toxic effects originating from various chemical, biological, or physical sources. This Review compiles studies performed on selected biomarkers with respect to both method development and application. Section 1 summarizes the concept of biomarkers; their application in various industrial/occupational, agricultural, drug developmental, and medical/clinical platforms. This section also focuses on biotransformation studies in close relation to biomarker discovery and validation, and on major techniques utilized in this area. In Section 2, biotransformation of volatile anesthetics in humans with a focus on mercapturic acid derivatives as potential biomarkers of effect is reviewed. The use of GC‐ECD, GC/MS, and 19F‐NMR in these studies is described. Section 3 focuses on the analysis of aldehydic lipid peroxidation degradation products by GC‐ECD in mammalian cells in which oxidative stress induced chemically, and in humans after various challenges; anesthetic exposure, ischemia‐reperfusion, and controlled endurance exercise. In Section 4, method development for protein and DNA oxidation products by LC‐tandem MS and its application in mammalian cells and in humans are summarized. Possibilities, limitations, and future perspectives are discussed in Section 5.
Polyurethane Shape‐Memory Polymers Demonstrate Functional Biocompatibility In Vitro
Authors: Cabanlit Maricel , Maitland Duncan , Wilson Thomas , Simon Scott , Wun Theodore , Gershwin M. Eric , Van de Water Judy
Published: January 2007

Shape memory polymers (SMPs) are a class of polymeric materials used in various medical interventions such as vascular stents. In this work, two SMPs, thermoplastic (TP) and thermoset (TS), have been measured in vitro for the degree of cellular and protein adhesion, their ability to stimulate inflammatory cytokine production, as well as the effects of the SMPs on the haemostatic system. The stimulatory properties of SMPs on neutrophils have also been directly addressed. Based on the studies of SMP biocompatibility as defined by inflammation, thrombogenesis, and the activation of both platelets and neutrophils, the TS and TP SMP materials are unlikely to stimulate an inflammatory response in vivo.

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Elucidating the Biosynthesis of Chitin Filaments and their Configuration with Specific Proteins and Electron Microscopy
Authors: Siemieniewicz Krzysztof W. , Kajla Mayur K. , Schrempf Hildgund
Published: January 2007

To deepen the knowledge of chitin synthesis, a yeast mutant has been used as a model. Purified chitin synthase I‐containing vesicles (chitosomes) with a diameter of 85 to 120 nm are identified by electron microscopy to eject tiny fibers upon addition of UDP‐N‐acetylglucosamine. The filigree of extruded filaments fused gradually into a large three‐dimensional network, which is degradable by a chitinase. The network is targeted and restructured by the Streptomyces chitin‐binding protein CHB1, which has a very high affinity only for α‐chitin. Within the chitosomes, filaments are found to be highly condensed within consecutive oval fibroids, which are specifically targeted by the α‐chitin‐binding protein. The presented data give new insights to the generation of chitin filaments with an antiparallel (α) configuration.

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Preparation of Cross‐Linked Poly[(ε‐caprolactone)‐co‐lactide] and Biocompatibility Studies for Tissue Engineering Materials
Authors: Miyasako Hiroshi , Yamamoto Kazuya , Nakao Aiko , Aoyagi Takao
Published: January 2007

In this study, cross‐linked materials were prepared using the branched macromonomer with different CL/LA molar ratios, and feasibility studies for tissue engineering were carried out. The thermal and mechanical properties of these materials depended on the CL/LA compositions; however, there was no change in the wettability of each material. The HeLa cells adhesion and growth on the CL‐LA7030c were equal to that on the commercially available polystyrene dish. The protein absorption experiment using the FBS proteins revealed that the materials with well‐grown cells showed better adhesion of the proteins.

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Cover Picture: Macromol. Biosci. 1/2007
Authors: Siemieniewicz Krzysztof W. , Kajla Mayur K. , Schrempf Hildgund
Published: January 2007

Cover: Biological nano‐machineries presenting vesicles (chitosomes) comprising chitin synthaseI were used to explore by electron microscopy the synthesis of filaments with or without chitinase or chitin‐binding protein CHB1, targeting very specifically a‐chitin. The data give new insights on how chitin‐fibres in a‐configuration are generated. Further details can be found in the article by K. W. Siemieniewicz, M. K. Kajla, and H. Schrempf*on page 40.
Hyperbranched Polymer/TiO2 Hybrid Nanoparticles Synthesized via an In Situ Sol‐Gel Process
Authors: Di Gianni Anna , Trabelsi Sondes , Rizza Giancarlo , Sangermano Marco , Althues Holger , Kaskel Stefan , Voit Brigitte
Published: January 2007

Two different kinds of HBPs were used in the preparation of nanocomposite materials based on TiO2 nanoparticles. One of the HBPs was characterized by the presence of free OH end groups in its structure, while the other one was obtained via a partial modification reaction which allowed to introduce some alkoxysilane functional groups. The TiO2 particles were prepared in situ in the polymer solution by means of a sol‐gel process starting from Ti(iOPr)4 as precursor. The polymer/TiO2 mixture, subsequently coated and cured in the presence of diisocyanate, gave rise to a hard coating. TiO2 was found to be dispersed on nanometer scale inside the final coatings obtained from both the polymers, and the TiO2 nanocomposite coatings were also characterized by improved thermal and hardness properties compared to TiO2 free systems. Still the two different kinds of HBPs showed a different interaction with the TiO2 particles, and it has been evidenced that the modification is required to achieve a better dispersion of the particles in the matrix and better properties for the final coating. Thus, by applying the modified HBP, TiO2 could be dispersed and stabilized in the polymer matrix as individual nanoparticles of only 6 nm in diameter.

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Poly(propylene)‐Layered Silicate Nanocomposites: Gas Permeation Properties and Clay Exfoliation
Authors: Osman Maged A. , Mittal Vikas , Suter Ulrich W.
Published: January 2007

To monitor the mineral surface coverage and energy, the inorganic cations of two clays (montmorillonite) with different surface area/cation have been exchanged by alkylammonium ions, carrying alkyl chains of different number and length. The prepared OMs were free of unreacted organic ions. With increasing length and number of the alkyl chains, an increase in the basal‐plane spacing (d‐spacing) of the OM was observed. The d‐spacing also increased with increasing CEC of the clay (decreasing available area/cation). The OMs were compounded with PP and their effect on the crystallinity and gas‐barrier properties of the polymer was investigated. The OM had no influence on the degree of crystallinity of PP under the processing conditions used. Oxygen permeation through the composites decreased, depending on the cross‐sectional area of the exchanged organic cation and the CEC of the clay. These parameters control the mineral surface coverage (consequently the surface energy) as well as the tilt angle of the alkyl chains to the mineral surface, and hence the d‐spacing. Increasing the length of the alkyl chains and their number per cation enhanced the d‐spacing, clay exfoliation, and the gas‐barrier properties of the composites. A mixed morphology, consisting of delaminated aluminosilicate layers and OM tactoids of varying thickness was observed but no intercalation took place. The oxygen permeation coefficient of the nanocomposites was found to be a non‐linear function of the volume fraction of the inorganic part of the OM.

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Synthesis via ATRP and Anchoring Properties of Ammonium‐Terminated Monofunctional or Telechelic Polystyrenes
Authors: Toquer Guillaume , Monge Sophie , Antonova Krassimira , Blanc Christophe , Nobili Maurizio , Robin Jean‐Jacques
Published: January 2007

Mono‐ and di‐(trimethylammonium)‐terminated polystyrenes with similar molar masses were synthesized. Bromopolystyrenes were first prepared by atom transfer radical polymerization (ATRP) using (N‐Boc‐propylamino)‐2‐bromoisobutyrate as initiator and Cu(I)Br/2,2′‐bipyridine as catalytic system in bulk at 110 °C. α,ω‐Telechelic polymer with double molecular weight with respect to the starting polystyrene was then obtained under atom transfer radical coupling process using 2,2′‐bipyridine and copper(0) mediated reductive conditions in anisole. Final (trimethylammonium)‐terminated polystyrenes were eventually obtained after removal of the tert‐butyloxycarbonyl group and permethylation reactions. Intermediate and final polymers were characterized by 1H NMR. The aligning properties of the obtained polymers for liquid crystals have been investigated. Pretilt and zenithal anchorings on ITO/glass substrates were measured. Finally, the possibility for the telechelic polystyrene to form a network in an inverted microemulsion was also considered.

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Cover Picture: Macromol. Mater. Eng. 1/2007
Authors: Wang Shi‐Qing
Published: January 2007

Cover: Building a proper molecular‐level description of polymer flow is a formidable task: How do entangled chains respond to shear deformation? Can the tube model depict elastic breakup? How to walk on this two‐way road linking molecular structures to macroscopic behavior? Polymer is like elastic noodles. PTV (particle‐tracking velocimetry) helps us detect their averaged flow responses. Further details can be found in the article by S.‐Q. Wang on page 15.
Rheology and Physical Properties of Polyethylene/Polyethylene‐Ionomer Blends and their Clay Nanocomposites
Authors: Lee Jennifer A. , Kontopoulou Marianna , Parent J. Scott
Published: January 2007

Rheological and solid‐state physical properties of blends containing high‐density polyethylene (HDPE) and a polyampholyte derivative (PE‐g‐PA) are assessed along with their onium ion‐exchanged montmorillonite clay (NR‐MM) nanocomposites. Strong deviations from the log‐additivity rule of zero‐shear viscosity, combined with synergistic behavior in tensile moduli, are consistent with a multi‐phase blend morphology. While this affects clay dispersion in filled blends, PE‐g‐PA/HDPE based nanocomposites are shown to exhibit a favorable balance between material stiffness and ductility.

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Laser‐Induced Crosslinking of Ultra‐Low‐ and High‐Density Polyethylene
Authors: Khan Ferdous , Kwek Diana , Kronfli Esam , Ahmad Sheikh Rafi
Published: January 2007

The use of laser radiation to initiate the crosslinking process in ultra low‐density polyethylene (ULDPE) and high‐density polyethylene (HDPE) was evaluated. The process was found to be most effective for pulsed laser irradiation when the polymer was traced with a photoinitiator: 4‐chlorobenzophenone (CBP). The gel content measurements proved that crosslinking took place in all the irradiated samples. The degree of crosslinking was measured for different values of irradiation energy, temperature, photoinitiator concentration and the nature and type of crosslinking agents. The effects of all these parameters on the degree of crosslinking and the consequent effects on mechanical properties of the polymers were analyzed. Also found in the present study is the fact that a better efficiency of crosslinking was achieved at longer laser irradiation wavelength. The ultimate tensile stress and elongation at fracture were measured for all cross‐linked samples and compared with those of the controlled ones.

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A Novel Route to the Preparation of Poly(N‐isopropylacrylamide) Microgels by Using Inorganic Clay as a Cross‐Linker
Authors: Zhang Qingsong , Zha Liusheng , Ma Jinghong , Liang Borun
Published: January 2007

Adopting inorganic clay (hectorite) and MBA as physical and chemical cross‐linking agents, respectively, PNIPAM microgels were synthesized by SFEP. The chemical structure and morphology of the microgels were confirmed by FTIR, WXRD, and SEM. The temperature‐sensitivity of the microgels was investigated by DLS and UV spectrophotometers. The results inferred that clay platelets dispersed in an aqueous medium were fully exfoliated and could act as a kind of multifunctional cross‐linking agent and significantly reduced the hydrodynamic diameters of the microgels. In fact, the hydrodynamic diameters of the PNIPAM microgels with clay as cross‐linker ranged from 154 to 322 nm which was much smaller than that using MBA as chemical cross‐linker, the later was in the range of 284–808 nm on heating from 5 to 50 °C.

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Measurement of trace atmospheric species by chemical ionization mass spectrometry: Speciation of reactive nitrogen and future directions
Authors: Huey L. Gregory
Published: January 2007

Chemical ionization mass spectrometry (CIMS) has proven to be a powerful method for sensitive, fast time response (t∼1 sec) measurements of various atmospheric compounds with limits of detection (LOD) of the order of tens of pptv and lower. The rapid time response of CIMS is particularly well suited for airborne measurements and its application has largely grown out of airborne measurements in the stratosphere and upper troposphere. This work reviews some of the advances in CIMS technology that have occurred in the past decade. In particular, CIMS methods for selective measurement of reactive nitrogen species (e.g., HNO3, HO2NO2, PAN, and NH3) in the lower atmosphere (altitudes ∼0–8 km) are described. In addition, recent developments in CIMS technology for the selective measurement of gas‐phase hydroperoxides and aerosol chemical composition are briefly described. © 2007 Wiley Periodicals, Inc., Mass Spec Rev 26:166–184, 2007
Free‐Radical Dispersion Polymerization of Methyl Methacrylate in Supercritical Carbon Dioxide: A Parametric Analysis with Reaction Calorimetry
Authors: Mantelis Charalampos A. , Barbey Raphaël , Fortini Sophie , Meyer Thierry
Published: January 2007

In an attempt to reduce the emission of hazardous VOCs, SCFs have been intensively investigated as alternative solvents during the last two decades. In this study, the application of reaction calorimetry, an efficient tool to obtain kinetic and safety data, is presented on the free radical dispersion polymerization of MMA in scCO2. The effect of three major parameters with respect to the reaction evolution are studied, namely of stirrer type and stirring speed, the monomer and CO2 concentration and the stabilizer concentration. The effective formation of the dispersion as well as the balance between the polymer formed in the continuous phase or inside the particles are key features of this analysis.

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Effects of Hydrogen for Different Stereospecific Active Sites on Ultra Low TiCl3 Loading Supported Catalyst
Authors: Kouzai Iku , Liu Boping , Wada Tooru , Terano Minoru
Published: January 2007

The relationship between the stereospecificity of active sites and hydrogen effects on propylene polymerization was investigated for MgCl2‐supported TiCl3 catalysts at ultra‐low Ti contents. Hydrogen had no effect on the catalyst activities for isospecific sites and for aspecific sites. The efficiency of hydrogen as a chain‐transfer agent was found to depend on the stereospecificity of the active sites. Hydrogen was effective for isospecific sites but was not effective for aspecific sites. From the viewpoint of hydrogen dissociation, isospecific sites should have hydrogen dissociation sites in their surroundings. Therefore, isospecific sites may be in the island to be affected by hydrogen and isolated sites may be aspecific or have low isospecificity.

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An unusual myopathy: Speckled muscle fibers due to enlarged mitochondria
Authors: Jeffree Rosalind L. , Wills Edward J. , Harper Clive
Published: January 2007

We report a 52‐year‐old woman who presented with a 6‐month history of proximal muscle weakness, elevated serum creatine kinase, and myopathic pattern on electromyography (EMG). Histology of the muscle shows a speckled pattern due to clustering of enlarged mitochondria. The pathology resembles that of selenium deficiency. The patient was found to have borderline low serum selenium and also low vitamin D and thyroid‐stimulating hormone. The cause of this unusual myopathy is probably multifactorial. This case is important because the unusual pathological picture represents a potentially treatable myopathy. In addition, we hope that publication of the complex clinical and biochemical abnormalities of this case, in conjunction with other case reports, may facilitate future elucidation of muscle mitochondrial function and dysfunction. Muscle Nerve, 2007
Stress, optimism, and social support: Impact on immune responses in breast cancer
Authors: Ah Diane Von , Kang Duck‐Hee , Carpenter Janet S.
Published: January 2007

The purpose of this study was to examine the direct and stress‐buffering effect of optimism and satisfaction with social support on immune responses in women with breast cancer. Participants were 54 post‐operative (M = 19 days) breast cancer patients who completed questionnaires on stress, optimism, and satisfaction with social support and provided blood to measure natural killer cell activity (NKCA) and interferon‐gamma (IFN‐γ) from whole blood. Higher levels of stress were associated with decrements in NKCA and IFN‐γ. Optimism moderated the relationship of stress on NKCA but was not related to IFN‐γ. Satisfaction with social support was unrelated to immune responses. Results suggest that interventions aimed at reducing stress and enhancing optimism in women with breast cancer might promote optimal immune response. © 2007 Wiley Periodicals, Inc. Res Nurs Health 30: 72–83, 2007
The enduring and contextual effects of physical health and depression on care‐dyad mutuality
Authors: Lyons Karen S. , Sayer Aline G. , Archbold Patricia G. , Hornbrook Mark C. , Stewart Barbara J.
Published: January 2007

Mutuality is a protective factor in family care situations, but little is known about changes in care‐dyad mutuality. In this study, we examined mutuality in 103 care dyads over 20 months, and the enduring and contextual impact of older adult and family caregiver health on changes in mutuality. Care dyads consisted of frail older adults and their family caregiver. Older adults reported higher levels of mutuality than family caregivers, but their mutuality declined significantly faster over time. Although changes in physical health were more important than mean health for both older adults and family caregivers, mean depression was more important than changes in depression for older adults. This study shows the importance of examining time‐varying covariates in the care dyad. © 2007 Wiley Periodicals, Inc. Res Nurs Health 30: 84–98, 2007
Summarizing benchmarks in the national database of nursing quality indicators using bootstrap confidence intervals
Authors: Gajewski Byron , Hall Matthew , Dunton Nancy
Published: January 2007

When summarizing the benchmarks for nursing quality indicators with confidence intervals around the means, bounds too high or too low are sometimes found due to small sample size or violation of the normality assumption. Transforming the data or truncating the confidence intervals at realistic values can solve the problem of out of range values. However, truncation does not improve upon the non‐normality of the data, and transformations are not always successful in normalizing the data. The percentile bootstrap has the advantage of providing realistic bounds while not relying upon the assumption of normality and may provide a convenient way of obtaining appropriate confidence intervals around the mean for nursing quality indicators. © 2006 Wiley Periodicals, Inc. Res Nurs Health 30: 112–119, 2007
Light measurement in the hospital: A comparison of two methods
Authors: Higgins Patricia A. , Winkelman Chris , Lipson Amy R. , Guo Su‐Er , Rodgers James
Published: January 2007

Disrupted sleep in hospitalized patients is widely reported, and ambient environmental lighting may be both a contributor to and a modifier of sleep/wake patterns. This is the first study to examine the congruence between two types of light meters, a wrist‐worn device and a stand‐alone device, and their respective light intensity measurements. The study sample included 20 light trials in 17 patients for a total of 480 paired light measurements. Descriptive data analysis indicated that both light meters dependably recorded changes in light levels, and Bland Altman plots demonstrated congruence between data from the two types of light meters. The results provide promising data on how to measure patient exposure to ambient light dependably in the continuously changing and unpredictable clinical setting. © 2007 Wiley Periodicals, Inc. Res Nurs Health 30: 120–128, 2007
Contexts and evolution of women's responses to miscarriage during the first year after loss
Authors: Swanson Kristen M. , Connor Sherri , Jolley Sandra N. , Pettinato Maria , Wang Tsae‐Jyy
Published: January 2007

Descriptions of 85 women's feelings about miscarriage at 1, 6, 16, and 52 weeks were inductively coded, rank‐ordered, and clustered into 3 responses: healing, actively grieving, and overwhelmed. Women who were actively grieving or overwhelmed at 1 week experienced significantly less distress from 6 weeks on. Responses at 1 week differed with regards to those who had a history of perinatal loss or went on to experience negative life events or sexual distance after loss. One year responses differed based on who was pregnant or gave birth, miscarried again, lived through a higher number of post‐loss negative life events, or experienced interpersonal or sexual distance from their mate. Responses were not influenced by gestational age at loss or having other children. © 2007 Wiley Periodicals, Inc. Res Nurs Health 30: 2–16, 2007
Using qualitative metasummary to synthesize qualitative and quantitative descriptive findings
Authors: Sandelowski Margarete , Barroso Julie , Voils Corrine I.
Published: January 2007

The new imperative in the health disciplines to be more methodologically inclusive has generated a growing interest in mixed research synthesis, or the integration of qualitative and quantitative research findings. Qualitative metasummary is a quantitatively oriented aggregation of qualitative findings originally developed to accommodate the distinctive features of qualitative surveys. Yet these findings are similar in form and mode of production to the descriptive findings researchers often present in addition to the results of bivariate and multivariable analyses. Qualitative metasummary, which includes the extraction, grouping, and formatting of findings, and the calculation of frequency and intensity effect sizes, can be used to produce mixed research syntheses and to conduct a posteriori analyses of the relationship between reports and findings. © 2006 Wiley Periodicals, Inc. Res Nurs Health 30: 99–111, 2007
Variation in the development of postcranial robusticity: an example from Çatalhöyük, Turkey
Authors: Cowgill L. W. , Hager L. D.
Published: January 2007

While the study of variation in adult postcranial robusticity has a long history, few analyses have examined the acquisition of postcranial robusticity within an ontogenetic context. This research evaluates differences in the ontogenetic trajectories of immature femora from three samples, in order to assess the point at which differences in levels of adult postcranial robusticity arise during development. Femoral midshaft cross‐sectional properties were compared between three diverse samples: Neolithic agriculturalists from Çatalhöyük, Turkey (n = 42); Byzantine agriculturalists from Çatalhöyük, Turkey (n = 24); and urban Americans from the Denver Growth Study (n = 151). While the two adult samples from Çatalhöyük do not differ statistically, both Neolithic and Byzantine adults have relatively larger cortical and total areas than the American urban adults, and these differences are clearly established by the age of six. In addition, by the age of three, individuals from the Denver Growth Study have already attained a greater percentage of their adult length, total area, and cortical area relative to those in both the Neolithic and Byzantine samples. These results indicate that the differing levels of postcranial robusticity characterising adult populations appear relatively early during development, and that populations vary in the rate and pattern through which adult levels of postcranial robusticity are achieved. Copyright © 2007 John Wiley & Sons, Ltd.
Intra‐individual variation in blood flow velocities in cerebral arteries of children with sickle cell disease
Authors: Brambilla Donald J. , Miller Scott T. , Adams Robert J.
Published: January 2007

Background

Children with sickle cell disease (SCD) are at elevated risk of stroke. Risk increases with blood flow velocity in selected cerebral arteries, as measured by transcranial Doppler (TCD) ultrasound, and use of TCD to screen these patients is widely recommended. Interpretation of TCD results should be based on knowledge of intra‐individual variation in blood flow velocity, information not currently available for sickle cell patients.

Procedures

Between 1995 and 2002, 4,141 subjects, 2–16 years old, with homozygous SCD or Sβ0‐thalasemmia and no history of stroke were screened with TCD, including 2,018 subjects screened in one clinical trial (STOP), 1,816 screened in another (STOP 2), and 307 screened in an interim ancillary prospective study. The 812 subjects with ≥2 examinations <6 months apart were selected for analysis, including 242 (29.8%) subjects with normal average velocities (i.e., <170 cm/sec), 350 (43.1%) subjects with conditional velocities (i.e., 170–199 cm/sec), and 220 (27.1%) subjects with abnormal velocities (i.e., ≥200 cm/sec). The intra‐subject standard deviation of TCD velocity was estimated from the difference between velocities at the first two interpretable examinations on each subject.

Results

An intra‐subject standard deviation of 14.9 cm/sec was obtained. Seven (0.9%) subjects had unusually large and unexplained differences between velocities at the two examinations (range of absolute differences: 69–112 cm/sec).

Conclusions

While stroke risk is well demonstrated to increase with increasingly abnormal TCD velocity, given the relatively large intra‐subject variability, one TCD examination is generally not sufficient to characterize stroke risk in this patient population. Pediatr Blood Cancer 2007;49:318–322. © 2007 Wiley‐Liss, Inc.
Nuchal translucency measurement and congenital heart defects: modest association in low‐risk pregnancies
Authors: Müller M. A. , Clur S. A. , Timmerman E. , Bilardo C. M.
Published: January 2007

Objective

To assess the performance of nuchal translucency (NT) measurement in the first trimester of pregnancy as a marker for congenital heart defects (CHD) in the fetus in a low‐risk obstetric population.

Methods

Nuchal translucency screening was offered over a 3‐year period to consecutive pregnant women without known a priori risk factors and attending midwife practices in three different areas in the Netherlands. In chromosomally normal fetuses and infants from the study population the NT measurements were matched with CHD detected either prenatally or postnatally.

Results

NT screening was offered to 6132 women with an uptake of 83%. A total of 4876 NT measurements was performed. Pregnancy outcome data were available in 4181 cases (86%). Defects of the heart and great arteries (CHD) were diagnosed in 24 cases (prevalence 5.8/1000). Thirteen of these were classified as major (prevalence 3.1/1000). Two major CHD occurred in fetuses showing an increased NT at the first‐trimester scan. The sensitivity of NT measurement > 95th and > 99th percentile for all CHD and for major CHD, was 8% and 15%, respectively. The positive likelihood ratios of NT > 95th and > 99th percentile for major CHD were 6, 5 and 33, respectively.

Conclusion

In pregnancies without known risk factors also, an increased NT is associated with major cardiac defects in the fetus and therefore represents an indication for specialized fetal echocardiography. However, this association is too weak to envisage a role for NT measurement as single screening strategy for the prenatal detection of cardiac defects. Copyright © 2007 John Wiley & Sons, Ltd.