bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite homomorphism‐homogeneous tournaments with loops
Authors: Ilić Andreja , Mašulović Dragan , Rajković Uroš
Published: June 2008

A structure is called homogeneous if every isomorphism between finite substructures of the structure extends to an automorphism of the structure. Recently, Cameron and Nešetřil introduced a relaxed version of homogeneity: we say that a structure is homomorphism‐homogeneous if every homomorphism between finite substructures of the structure extends to an endomorphism of the structure. In this article we characterize homomorphism‐homogeneous finite tournaments where vertices are allowed to have loops. © 2008 Wiley Periodicals, Inc. J Graph Theory 59: 45–58, 2008
Generation of dopamine neurons from embryonic stem cells in the presence of the neuralizing activity of bone marrow stromal cells derived from adult mice
Authors: Shintani Aki , Nakao Naoyuki , Kakishita Koji , Itakura Toru
Published: June 2008

Stromal cell lines such as PA6 and MS5 have been employed for generating dopamine (DA) neurons from embryonic stem (ES) cells. The present study was designed to test whether bone marrow stromal cells (BMSC) derived from adult mice might be available as a feeder layer to produce DA cells efficiently from ES cells. When ES cells were grown on BMSC in the presence of fibroblast growth factor 8 (FGF8) and sonic hedgehog (SHH), about 40% of TuJ1‐positive neurons expressed tyrosine hydroxylase (TH). Because these cells labeled with TH were negative for dopamine‐β‐hydroxylasae (DBH), the marker for noradrenergic and adrenergic neurons, the TH‐positive cells were most likely DA neurons. They indeed expressed midbrain DA neuron markers such as Nurr 1, Ptx‐3, and c‐ret and were capable of synthesizing and releasing DA in vitro. Furthermore, DA neurons differentiated from ES cells in this differentiation protocol survived transplantation in rats with 6‐hydroxydopamine lesions and reversed the lesion‐induced circling behavior. The data indicate that BMSC can facilitate an efficient induction of DA neurons from ES cells and that the generated DA neurons are biologically functional both in vitro and in vivo. Insofar as BMSC have recently been employed in autologous cell therapy for ischemic heart and arteriosclerotic limb diseases, the present study raises the possibility that autologous BMSC can be applied in future cell transplantation therapy in Parkinson's disease. © 2008 Wiley‐Liss, Inc.
Expression of Foxp4 in the developing and adult rat forebrain
Authors: Takahashi Kaoru , Liu Fu‐Chin , Hirokawa Katsuiku , Takahashi Hiroshi
Published: June 2008

Many members of the Fox family are transcription factors that regulate the morphogenesis of various organs. In the present study, we examined the expression pattern of Foxp4, a member of the Foxp subfamily, and compared its pattern with the patterns of Foxp2 and Foxp1 in the developing rat brain. In general, these three Foxp genes shared partially overlapping and yet differentially regulated expression patterns in the striatum, the cerebral cortex, and the thalamus during development. In the developing dorsal telencephalon, a mediolateral gradient of Foxp4 was present in the cortical primordium, with high levels in the ventricular zone of the medial cortex. By contrast, no gradient of Foxp2 and Foxp1 was detected in the dorsal telencephalon. At later stages, Foxp4 was expressed throughout all cortical layers as opposed to the layer‐specific expression of Foxp2 and Foxp1. In the developing striatum, the pattern of Foxp4 expression was distinct from the patterns of Foxp2 and Foxp1. The spatial expression pattern of Foxp4 was similar to that of Foxp2 during the early embryonic stage. However, from the late embryonic stage to postnatal day 4, Foxp4 was expressed in a mediolateral gradient and decreased in the striosomal compartment, in contrast to the striosomal expression of Foxp2 and homogeneous expression of Foxp1. Foxp4 was developmentally down‐regulated such that Foxp4 was undetectable in the forebrain after postnatal day 14, whereas Foxp2 and Foxp1 were persistently expressed in adulthood. Given that Foxp4, Foxp2, and Foxp1 are capable of heterodimerization for transcriptional regulation, the partially overlapping expression patterns of Foxp4, Foxp2, and Foxp1 in different domains of the developing forebrain suggest that each member and/or different combinatory actions of the Foxp subfamily may play a pivotal role in regulating forebrain development. © 2008 Wiley‐Liss, Inc.
Pressurized CEC of neutral and charged solutes using silica monolithic stationary phases functionalized with 3‐(2‐aminoethylamino)propyl ligands
Authors: Huang Guihua , Zeng Wencan , Lian Qiuyan , Xie Zenghong
Published: June 2008

A novel silica monolithic stationary phase functionalized with 3‐(2‐aminoethylamino)propyl ligands for pressurized CEC has been presented. The monolithic capillary columns were prepared by a sol‐gel process in 75 μm id fused‐silica capillaries and followed by a chemical modification. The diamino groups on the surface of the stationary phase are meant to generate the chromatographic surface and a substantial anodic EOF as well as to provide electrostatic interaction sites for charged solutes. The electrochromatographic characterization and column performance were evaluated by a variety of neutral and charged solutes. It was observed that the anodic EOF for the diamine‐bonded monolith was greatly affected by the reaction time with 3‐(2‐aminoethylamino)propyltrimethoxysilane and the PEG amount in the sol‐gel reaction mixture in addition to the mobile phase conditions. The monolithic stationary phase exhibited hydrophilic interaction chromatographic behavior toward neutral solutes. Good separations of various solutes including phenols, nucleic acid bases, nucleosides and nucleotides were achieved under different experimental conditions. Fast and efficient separations were obtained with high plate counts reaching more than 130 000 plates/m.
Non‐destructive assessment of inhibition of demineralization in dental enamel irradiated by a λ = 9.3‐µm CO2 laser at ablative irradiation intensities with PS‐OCT
Authors: Can Anna M. , Darling Cynthia L. , Ho Chi , Fried Daniel
Published: June 2008

Background and Objective

Polarization sensitive optical coherence tomography (PS‐OCT) has great promise for the non‐destructive assessment of the efficacy of anti‐caries agents such as fluoride and thermal laser treatments on enamel surfaces. The purpose of this study was to demonstrate that PS‐OCT can be used to measure demineralization in craters/incisions prepared in enamel by a CO2 laser operating at the high irradiation intensities required for cavity preparations.

Materials and Methods

Incisions in bovine enamel surfaces were produced by a CO2 laser used with a water spray. The laser was operated at λ = 9.3 µm with a pulse duration of 15 µs and an incident fluence of 20 J/cm2. The laser treatments were also combined with topical fluoride treatments. A PS‐OCT system operating at 1,310 nm was used to acquire polarization resolved images of six areas including sound and laser‐ablated+topical fluoride treated zones on each sample. After imaging the teeth, they were sectioned and the thin sections were examined with polarized light microscopy (PLM) and transverse microradiography (TMR). The integrated reflectivity and lesion depth derived from the PS‐OCT scans, the integrated mineral loss and depth measured using TMR and the lesion depth measured with PLM were acquired for each area on the fifteen samples for comparison.

Results

The integrated reflectivity and depth in the areas treated by the laser and fluoride were significantly lower (P<0.05) than for the untreated enamel. Similar results were observed for TMR and PLM.

Conclusions

These results suggest that PS‐OCT has great potential for the non‐destructive “in vivo” assessment of the inhibition of demineralization by lasers at ablative irradiation intensities with and without topical fluoride application. Lesers Surg. Med. 40:342–349, 2008. © 2008 Wiley‐Liss, Inc.
Investigation of Nanoparticle Coating by Fluorescence Correlation Spectroscopy
Authors: Jurkiewicz Piotr , Koňák Čestmír , Šubr Vladimír , Hof Martin , Štĕpánek Petr , Ulbrich Karel
Published: June 2008

Protecting gene delivery vectors by hydrophilic copolymer coating is a promising approach in targeted gene therapy. Herein we demonstrate the usefulness of FCS in characterizing the coating process of a virus model – latex beads with coumarin‐labeledN‐(2‐hydroxypropyl)methacrylamide copolymer containing thiazolidine‐2‐thione groups. FCS gives an estimation of the average number of polymer chains coating the latex bead, which agrees with light scattering results, giving an evidence of quality of the vector surface modification. FCS is advantageous because it decreases the sample consumption by a factor of 1 000. The coumarin label showed advantages over the previously used fluorescein‐based one.

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The Process of Functional Conjugated Organic Polymers Derived from Triple‐Bond Building Blocks
Authors: Li Cuihong , Li Yuliang
Published: June 2008

Polyacetylenes, poly(p‐phenyleneethynylenes), and polydiacetylenes, as conjugated polymers derived from triple‐bond containing building blocks, attain considerable attention because of their electronic and photoconduction properties. In this review, recent studies on the design and synthesis of conjugated polymers derived from triple‐bond building blocks are summarized with an emphasis on the developments in our group in recent years. Our intense attention is focused on constructing different molecular systems with enhanced light‐harvesting efficiency, and determining the functional properties of conjugated organic polymers. The conjugated organic polymers that appear in this review are useful candidates for various potential applications because of their extraordinary optical and electronic properties. The potential applications of the conjugated polymer‐containing systems are explored.

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Morphological Behavior of Polystyrene‐block‐Polylactide/Polystyrene‐block‐Poly(ethylene oxide) Blends
Authors: Mao Huiming , Hillmyer Marc A.
Published: June 2008

The morphological behavior of PS‐containing diblock copolymer blends is reported. Three sets of PS/PLA and PS/PEO blends are prepared and evaluated by SAXS, WAXS, DSC, and DMA. No macrophase separation is observed, and the formation of PLA/PEO composite cylinders is identified by SAXS for all compositions. The PLA and PEO segments in these blends have been found to be miscible and the crystallization of the confined PEO is suppressed in the ordered nanostructures. The domain spacing, diameter of composite cylinders, and order/disorder transition temperature could be tuned by varying the blend composition in the binary blends.

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A Comparative Study of Nanosilica/Poly(propylene) Composites Prepared by Reactive Compatibilization
Authors: Chen Jing Hua , Rong Min Zhi , Ruan Wen Hong , Mai Yu Liang , Zhang Ming Qiu
Published: June 2008

A comparative study of nano‐SiO2/PP composites prepared by reactive compatibilization was conducted. Nano‐SiO2 was first grafted with three polymers bearing specific reactive groups. The grafted particles were then melt‐compounded with functionalized and matrix PP. Due to the reaction between the grafted polymers and functionalized PP, nano‐SiO2 was covalently connected to the matrix and the mechanical properties of the nanocomposites were significantly improved. It was found that chain flexibility of the graft polymers is critical for inducing plastic deformation of the matrix, provided that interfacial chemical bonding has been built up.

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Temperature‐ and pH‐Sensitive Nanocomposite Gels with Semi‐Interpenetrating Organic/Inorganic Networks
Authors: Song Liyuan , Zhu Meifang , Chen Yanmo , Haraguchi Kazutoshi
Published: June 2008

An intelligent nanocomposite hydrogel with a semi‐interpenetrating organic/inorganic network was synthesized through in situ free‐radical polymerization of NIPA in the presence of an inorganic clay and linear PAA. The resulting semi‐interpenetrating nanocomposite gels (sI‐NC gels) showed mechanical and swelling/deswelling properties greatly superior to those of other PNIPA/PAA hydrogels. The sI‐NC gels repeatedly changed their swelling behavior in response to both temperature and pH while retaining their remarkable mechanical properties. The structure and homogeneity of these networks were studied and related to the properties of sI‐NC gels and the hydrogen bonding interactions among the constituents.

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Flow‐Induced Orientation in Miscible Crystalline Polymer Blends of Poly(vinylidene fluoride) and Poly[(3‐hydroxybutyrate)‐co‐(3‐hydroxyvalerate)]
Authors: Kaito Akira , Nakayama Kazuo , Shimizu Hiroshi
Published: June 2008

Oriented films of miscible polymer blends of poly(vinylidene fluoride) and poly[(3‐hydroxybutyrate)‐co‐(3‐hydroxyvalerate)] were prepared using a flow‐orientation technique. The lamellar structure and crystal orientation depended upon composition and flow temperature (Tflow). An interlamellar exclusion structure was induced in the blend flow‐oriented below 150 °C, whereas an interlamellar inclusion structure was developed above 150 °C. The crystal orientation of PHBHV was affected by the lamellar structures because the PHBHV chains crystallized in the pre‐existing crystalline morphology of PVDF. Crystallization of PHBHV was markedly restricted at lower PHBHV contents.

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Alkyl Zinc Chlorides as New Initiators for the Polymerization and Copolymerization of Isobutene
Authors: Guerrero Antonio , Kulbaba Kevin , Bochmann Manfred
Published: June 2008

Mixtures of RZnCl and tBuCl (R = Et) initiate the polymerization of isobutene in the temperature range of (−35)—(+35) °C. The order of addition of the reagents is important for effective polymerization. Increasing the solubility of the zinc reagent (R = n‐octyl) and use of cumyl chloride as co‐initiator provides a system that is active from (−90)—(+35) °C. The molecular weights show a remarkably small temperature dependence, EDP = −3.3 kJ · mol−1, compared to EDP = −23 kJ · mol−1 in classical systems (AlCl3, EtAlCl2). The molecular weights increase with decrease in zinc concentration and are consistently higher for n‐octyl zinc chloride, as expected for a bulkier, less coordinating counteranion. The polymerizations are not retarded by isoprene addition; homopolymers and copolymers show essentially identical conversions and molecular weights.

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Organometallic Polymer Light‐Emitting Diodes Derived from a Platinum(II) Polyyne Containing the Bithiazole Ring
Authors: Wong Wai‐Yeung , Zhou Gui‐Jiang , He Ze , Cheung Kai‐Yin , Ng Alan Man‐Ching , Djurišić Aleksandra B. , Chan Wai‐Kin
Published: June 2008

The synthesis, thermal, and photoluminescence properties of novel platinum metallopolyynes of bithiazole derivatives trans‐[Pt(PR3)2‐C≡C‐Ar‐C≡C]n (Ar = 4,4′‐dibutyl‐2,2′‐bithiazole‐5,5′‐diyl P1; 4,4′‐dinonyl‐2,2′‐bithiazole‐5,5′‐diyl P2) and their molecular model complexes are described. The structural properties of the dinuclear model compound for P1 have been examined by X‐ray crystallography. In view of the electron‐donating and electron‐withdrawing nature of the thiazole rings in the main chain, a strong π‐conjugated system that features unique donor–acceptor interactions is created, which results in optical bandgaps of 2.40 eV. The optical gap of the polymer is notably reduced as compared to that for the more electron‐rich bithienyl analogue. Multi‐layer polymer light‐emitting diodes have been fabricated with the metallopolymer as the emitting layer, which give a green light color with the Commission Internationale de L'Eclairage (CIE) chromaticity coordinates of (0.26, 0.58) at 8 V.

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Atomic Force Microscopy Characterization and Interpretation of Thin‐Film Poly(butylene adipate) Spherulites with Ring Bands
Authors: Frömsdorf Andreas , Woo Eamor M. , Lee Li‐Ting , Chen Yu‐Fan , Förster Stephan
Published: June 2008

Atomic force microscopy characterization has been conducted to reveal the morphological difference between single‐ring bands in poly(butylene adipate) (PBA). Furthermore, morphological features of the ring‐less Maltese‐cross spherulites are compared to the ring‐band spherulites. Periodic changes in height seem to be common for either the ring‐band or ring‐less (Maltese‐cross) crystal domains; however, the steepness in height change is greater for the ring‐band crystal, while height change in the ring‐less crystal exhibits a terrace‐like layer pattern. In the ring‐band crystal region, the lamellar stalks, which taper off to pointed needle‐like stalks, monotonously protrude out of the layers of softer materials, with no signs of twisting, bending, or turning. In contrast, all lamellae in the ring‐less (Maltese‐cross) crystal region are uniform platelets arranged like flower petals in a layered pattern.

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G protein‐coupled receptors of the hypothalamic–pituitary–gonadal axis: A case for gnrh, LH, FSH, and GPR54 receptor ligands
Authors: Heitman Laura H. , IJzerman Adriaan P.
Published: June 2008

The hypothalamic–pituitary–gonadal (HPG) axis, important in reproduction and sex hormone‐dependent diseases, is regulated by a number of G protein‐coupled receptors. The recently “deorphanized” GPR54 receptor activated by the peptide metastin is thought to be the key regulator of the axis, mainly by releasing gonadotropin‐releasing hormone (GnRH) from the hypothalamus. The latter decapeptide, through the activation of the GnRH receptor in the anterior pituitary, causes the secretion of luteinizing hormone (LH) and follicle‐stimulating hormone (FSH), which subsequently activate their respective receptors on the gonadotrope cells. In this review we will discuss the small molecule agonists and antagonists that are currently being developed to intervene with the action of these four receptors. For GnRH receptors, 14 different chemical classes of non‐peptidic antagonists have been reported, while for the LH receptor three classes of agonists have been described. Both agonists and antagonists have been introduced for the FSH receptor. Recently, the first non‐peptidic agonist for GPR54 was reported. © 2008 Wiley Periodicals, Inc. Med Res Rev, 28, No. 6, 975–1011, 2008
Novel shaped‐beam microstrip slot array series FED by stepped‐impedance line
Authors: Hanqing M. A. , Chu Qing‐Xin , Qiuyi Zhang
Published: June 2008

A series‐fed eight‐slot microstrip array antenna operating at 3.5 GHz with a cosecant‐squared shape beam is presented. The shaped radiation pattern is achieved by changing only the characteristic impedance of the series fed line between slots. The proposed antenna has a shaped‐beam with elevation coverage of 35°, a gain of 10.86 dBi, and side lobe levels less than −19 dB. Since the slots and fed strip are fabricated on a single substrate, the antenna is easy to manufacture and low cost. Experimental results demonstrate the validity of this design. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2434–2437, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23662
An interpolated spatial images method for the analysis of multilayered shielded microwave circuits
Authors: Gómez‐Díaz J. S. , Martínez‐Mendoza M. , Pérez‐Soler F. J. , Álvarez‐Melcón A.
Published: June 2008

In this article, an efficient interpolation method is presented to compute the Green's function associated with electrical sources, when they are placed inside cylindrical cavities. The interpolation scheme is formulated in the frame of the spatial images technique recently developed. The original idea was to calculate, for every location of a point electric source, the complex values of the electric dipole and charge images, placed outside the cavity, to impose the appropriate boundary conditions for the potentials. To considerably reduce the computational cost of the original technique, a simple interpolation method is proposed to obtain the complex values of the images for any source location. To do that, a rectangular spatial subdivision inside the cavity is proposed. Each new subregion is controlled by means of the exact image values obtained when the source is placed at the four corners of the region. The key idea is to use a bilinear interpolation to obtain the image complex values when the source is located anywhere inside this subregion. The interpolated images provide the Green's functions of the new source positions fast, and with high accuracy. This new approach can be directly applied to analyze printed planar filters. Two examples with CPU time comparisons are provided, showing the high accuracy and computational gain achieved with the technique just derived. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2294–2300, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23683
Towards the automatic analysis of NMR spectra: Part 7. Assignment of 1H by employing both 1H and 1H/13C correlation spectra
Authors: Griffiths Lee , Beeley Howard H , Horton Rob
Published: June 2008

A reliable method of automatically assigning one‐dimensional proton spectra is described. The method relies on the alignment of the proton spectrum with an associated heteronuclear single‐quantum coherence (HSQC) spectrum, transferring the stoichiometry and couplings to the HSQC. The HSQC spectrum is then assigned using a linear assignment procedure in which a fitness function incorporating 1H chemical shifts, 1H couplings and 13C shifts are employed. The method uniquely employs a sequential procedure in which only correlations of like stoichiometry are assigned at the same time. Copyright © 2008 John Wiley & Sons, Ltd.
Identification of amide protons of glutathione in MR spectra of tumour cells
Authors: Grande Sveva , Luciani Anna Maria , Rosi Antonella , Guidoni Laura , Viti Vincenza
Published: June 2008

Signals attributable to amide protons and used in previous studies to measure intracellular pH were observed in the low‐field region of the 1H‐MR spectra of four tumour cell lines: T98G, MCF‐7, A172 and HeLa. The signals were more intense in the spectra of the two cell lines (T98G and MCF‐7) characterised by higher concentrations of glutathione (GSH). After comparison with 1H‐MR spectra of GSH in solution at different pH values, the peaks were attributed to NHs of the Cys and Gly residues of GSH. Modification of the intracellular concentration of GSH by treatment with buthionine sulfoximine produced comparable decreases in the intensity of aliphatic signals of GSH and NHs under examination. The assignment was therefore confirmed. Copyright © 2008 John Wiley & Sons, Ltd.
Do we truly see what we think we see? The role of cognitive bias in pathological interpretation
Authors: Fandel TM , Pfnür M , Schäfer SC , Bacchetti P , Mast FW , Corinth C , Ansorge M , Melchior SW , Thüroff JW , Kirkpatrick CJ , Lehr H‐A
Published: June 2008

In the histomorphological grading of prostate carcinoma, pathologists have regularly assigned comparable scores for the architectural Gleason and the now‐obsolete nuclear World Health Organization (WHO) grading systems. Although both systems demonstrate good correspondence between grade and survival, they are based on fundamentally different biological criteria. We tested the hypothesis that this apparent concurrence between the two grading systems originates from an interpretation bias in the minds of diagnostic pathologists, rather than reflecting a biological reality. Three pathologists graded 178 prostatectomy specimens, assigning Gleason and WHO scores on glass slides and on digital images of nuclei isolated out of their architectural context. The results were analysed with respect to interdependencies among the grading systems, to tumour recurrence (PSA relapse > 0.1 ng/ml at 48 months) and robust nuclear morphometry, as assessed by computer‐assisted image analysis. WHO and Gleason grades were strongly correlated (r = 0.82) and demonstrated identical prognostic power. However, WHO grades correlated poorly with nuclear morphology (r = 0.19). Grading of nuclei isolated out of their architectural context significantly improved accuracy for nuclear morphology (r = 0.55), but the prognostic power was virtually lost. In conclusion, the architectural organization of a tumour, which the pathologist cannot avoid noticing during initial slide viewing at low magnification, unwittingly influences the subsequent nuclear grade assignment. In our study, the prognostic power of the WHO grading system was dependent on visual assessment of tumour growth pattern. We demonstrate for the first time the influence a cognitive bias can have in the generation of an error in diagnostic pathology and highlight a considerable problem in histopathological tumour grading. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Expression of EpCAM is up‐regulated during regeneration of renal epithelia
Authors: Trzpis M , McLaughlin PM , van Goor H , Brinker MGL , van Dam GM , de Leij LM , Popa ER , Harmsen MC
Published: June 2008

The human epithelial cell adhesion molecule (hEpCAM) is involved in epithelial morphogenesis and repair of epithelial tissues. We hypothesized that changes in hEpCAM expression in vivo correlate with regeneration of renal epithelia after ischaemia/reperfusion injury (IRi). Unilateral IRi was performed on kidneys of hEpCAM transgenic mice. Changes in hEpCAM expression were investigated by quantitative RT‐PCR in renal cortex and medulla dissected by laser dissection microscopy and expression patterns of hEpCAM in regenerating kidneys were assessed by immunohistochemistry. The mechanism of hEpCAM promoter activation was investigated in vitro, by real‐time bioluminescent imaging in HK‐2 cells and in primary tubular epithelial cells (PTECs) subjected to hypoxia and reoxygenation. In vivo, the transcription of the human epcam gene significantly increased in the renal cortex during tubular re‐epithelialization (p < 0.01). Moreover, the number of tubuli that expressed hEpCAM protein more than doubled in the renal cortex during regeneration. De novo expression of hEpCAM was detected in the S1 segments of proximal tubuli. Under hypoxic conditions in vitro, activity of the hEpCAM promoter was up‐regulated two‐fold in the HK‐2 proximal epithelial cell line. Moreover, both in primary proximal epithelial cells and in HK‐2 cells, hEpCAM protein expression was increased after hypoxia and reoxygenation. The significant up‐regulation of hEpCAM during post‐ischaemic renal regeneration in vivo and during in vitro hypoxia indicates that hEpCAM expression is associated with renal regeneration. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Attitudes toward prenatal diagnosis and termination of pregnancy for genetic disorders among healthcare workers in a selected setting in Sri Lanka
Authors: de Silva Deepthi C. , Jayawardana P. , Hapangama A. , Suraweera E. G. D. N. , Ranjani D. , Fernando S. , Karunasena C. , Jinadasa S.
Published: June 2008

Objectives

Assess attitudes toward prenatal diagnosis (PND) and termination of pregnancy (TOP) for Down syndrome (DS), hemophilia, lethal autosomal recessive disorder (LRD) and a hypothetical late‐onset neurodegenerative disorder (NDD) among healthcare workers in one Sri Lankan district.

Methods

Self‐administered questionnaire (tested for content validity) completed by medical (n = 218) and nursing (n = 368) students, nurses (n = 178) and doctors (n = 127).

Results

Acceptability of PND was 94%, 91%, 86% and 71% respectively for LRD, DS, hemophilia and NDD. Favorable attitudes toward TOP for DS (84%), and LRD (82%) were higher compared with hemophilia (65%) and NDD (53%). There was willingness to consider TOP for self/spouse for DS (79%), LRD (78%), hemophilia (60%) and NDD (54%). The proportions willing to participate in a pregnancy termination (DS 54%, LRD 51%, hemophilia 38%, NDD 38%) were lower. Religious affiliation influenced attitudes regarding TOP with Christians being more opposed than Buddhists.

Conclusions

There is acceptance of and willingness to participate in TOP for fetal anomalies among Sri Lankan healthcare workers. These findings have relevance for developing prenatal diagnostic services in Sri Lanka. Religious affiliation among Asian doctors, nurses (and patients) in developed countries is likely to determine permissiveness toward PND and TOP. Copyright © 2008 John Wiley & Sons, Ltd.
An evaluation of the recording of folic acid use in the South West Congenital Anomaly Register
Authors: Mytton J. , Harrison V. , McLoughlin A. , Thompson R. , Overton T.
Published: June 2008

Objective

Some congenital anomaly registers are collecting data on risk factors for pregnancies affected by anomalies; yet the quality of that information is rarely assessed. We assessed the quality of the risk factor data in the South West Congenital Anomaly Register (SWCAR) through a review of the data held on folic acid use, in cases of neural tube defect (NTD).

Methods

We reviewed all cases of NTD reported to SWCAR over 2 years and compared information held in the register with that in handwritten and computerised prenatal records, where available.

Results

Data on folic acid use was recorded in only 41 (36.9%) of the prenatal records of the 111 cases of NTDs reviewed. Information on any folic acid use in the prenatal records was transferred to the register in all instances where it existed. Information on the time of taking folic acid or not taking folic acid was rarely recorded in prenatal records.

Conclusion

Incomplete recording of folic acid use and timing in prenatal records has limited the ability of SWCAR to collect accurate information on folic acid use in cases of NTDs. Minimal recording information on folic acid use in prenatal records is suggested. Copyright © 2008 John Wiley & Sons, Ltd.
Morphology and crystalline properties of impact‐modified polypropylene blends
Authors: Tortorella Nathan , Beatty Charles L.
Published: June 2008

Isotactic polypropylene has been reactively blended with an ethylene‐octene copolymer so as to improve mechanical and rheological properties. Free radical polymerization of styrene and a multifunctional acrylate during melt extrusion has resulted in the formation of unique features in both amorphous and crystalline phases. Transmission electron microscopy images show that the elastomer domains are less than 200 nm in diameter, whereas grafting leads to the appearance of clusters of polymeric particles, ranging in size from several nanometers up to 200 nm. Differential scanning calorimetry (DSC) shows that grafting creates lamellar crystals that melt at much lower temperatures and recrystallize at much higher temperatures than binary blends. From wide angle X‐ray diffraction and DSC, grafting has been shown to limit the maximum crystal size and perfection, as well as broaden the size distribution of the crystals. Grafting causes significant changes in the α crystalline phase of polypropylene and promotes the formation of the β phase. Scanning electron microscopy reveals a unique cross‐hatch structure of small crystals in the reactive blend, with tangential and radial lamellae appearing as crosslinked material of about the same aspect ratio. Polarized light microscopy gives evidence that grafting and branching within this blend causes a gelation‐like recrystallization. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Proteomic analysis of spore wall proteins and identification of two spore wall proteins from Nosema bombycis (Microsporidia)
Authors: Wu Zhengli , Li Yanhong , Pan Guoqing , Tan Xiaohui , Hu Junhua , Zhou Zeyang , Xiang Zhonghuai
Published: June 2008

Microsporidia are fungal‐like unicellular eukaryotes which develop as obligate intracellular parasites. They differentiate into resistant spores that are protected by a thick spore wall composed of a glycoprotein‐rich outer layer or exospore and a chitin‐rich inner layer or endospore. In this study performed on the silkworm pathogen Nosema bombycis, we analyzed the spore wall proteins (SWPs) by proteomic‐based approaches, MALDI‐TOF MS and LC‐MS/MS, and 14 hypothetical spore wall proteins (HSWPs) or peptides were obtained in total. Furthermore, we have examined the SWPs by SDS‐PAGE and three main spore wall peptides were detected with molecular weights of 32.7 kDa (SWP32), 30.4 kDa (SWP30), and 25.3 kDa (SWP25), respectively. By N‐terminal amino acid residue sequencing, and searching the genomic DNA shotgun database of N. bombycis, the complete ORFs of SWP30 and SWP32 were obtained, which encode for a 278‐ and a 316‐amino acid peptide, respectively. Mouse polyclonal antibodies were raised against SWP30 and SWP32 recombinant proteins produced in Escherichia coli, and the results of indirect immunofluorescence assay (IFA) and immunoelectron microscopy (IEM) analyses indicated SWP30 to be an endosporal protein while SWP32 was shown to be an exosporal protein. Both SWP30 and SWP32 are included in the 14 HSWPs identified by MS, confirming the results of the proteomic‐based approaches. (GenBank™, EMBL and DDBJ accession numbers: NbHSWP1–NbHSWP12, accession no. EF683101–EF683112. NbHSWP13 and NbHSWP14, accession no. EU179719 and EU179720).
Negative‐type photosensitive poly(phenylene ether) based on poly(2,6‐dimethyl‐1,4‐phenylene ether), a crosslinker, and a photoacid generator
Authors: Mizoguchi Katsuhisa , Ueda Mitsuru
Published: June 2008

A negative‐type photosensitive poly(phenylene ether) (PSPPE) based on poly(2,6‐dimethyl‐1,4‐phenylene ether) (PPE), a novel crosslinker 4,4′‐methylene‐bis [2,6‐bis(methoxymethyl)phenol] (MBMP) having good compatibility with PPE, and diphenylidonium 9,10‐dimethoxy anthracene‐2‐sulfonate (DIAS) as a photoacid generator (PAG) has been developed. This resist consisting of PPE (73 wt %), MBMP (20 wt %) and DIAS (7 wt %) showed a high sensitivity (D0.5) of 58 mJ/cm2 and a contrast (γ0.5) of 9.5 when it was exposed to i‐line (365 nm wavelength light), postexposure baked at 145 °C for 10 min, and developed with toluene at 25 °C. A fine negative image featuring 6 μm line‐and‐space pattern was obtained on the film exposed to 300 mJ/cm2 of i‐line by a contact‐printed mode. The resulting polymer film cured at 300 °C for 1 h under nitrogen had a low dielectric constant (ε = 2.46) comparable to that of PPE and a higher Tg than that of PPE. In addition, the cured PSPPE film was pretty low water absorption (<0.05%) as same as PPE. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4949–4958, 2008
From the discovery of sodiumoxyorganoalkoxysilanes to the organosilicon dendrimers and back
Authors: Muzafarov Aziz M. , Rebrov Evgenij A.
Published: June 2008

Upon being discovered 20 years ago, sodiumoxyorganoalkoxysilanes became the key to the world of organoelement dendrimers. Even considering the great variety of objects that had appeared in this area during the last 20 years, the organosilicon dendrimers are still one of the most actual objects in this class. Above all, this is fair concerning the carbosilane systems. The high reactivity of the functional groups, the well controlled chemistry of their transformations, and the inertness of the molecular skeleton are the reason for making these systems highly actual in two main regards: as model objects for the deep research of the dendrimers' properties and as polyfunctional matrixes for numerous derivatives. In this review, we were mainly focusing on the importance of the former part. In the conclusion, we showed the motivation for further development of this area both in regard of synthesis of new carbosilane systems and further development of siloxane dendrimers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4935–4948, 2008
Effect of prepolymer molecular weight on solid state polymerization of poly(bisphenol a carbonate) with nitrogen as a sweep fluid
Authors: Kim Jaehoon , Roberts George W. , Kiserow Douglas J.
Published: June 2008

The effect of prepolymer molecular weight on the solid‐state polymerization (SSP) of poly(bisphenol A carbonate) was investigated using nitrogen (N2) as a sweep fluid. Prepolymers with different number–average molecular weights, 3800 and 2400 g/mol, were synthesized using melt transesterification. SSP of the two prepolymers then was carried out at reaction temperatures in the range 120–190 °C, with a prepolymer particle size in the range 20–45 μm and a N2 flow rate of 1600 mL/min. The glass transition temperature (Tg), number–average molecular weight (Mn), and percent crystallinity were measured at various times during each SSP. The phenyl‐to‐phenolic end‐group ratio of the prepolymers and the solid‐state synthesized polymers was determined using 125.76 MHz 13C and 500.13 MHz 1H nuclear magnetic resonance (NMR) spectroscopy. At each reaction temperature, SSP of the higher‐molecular‐weight prepolymer (Mn = 3800 g/mol) always resulted in higher‐molecular‐weight polymers, compared with the polymers synthesized using the lower molecular weight prepolymer (Mn = 2400 g/mol). Both the crystallinity and the lamellar thickness of the polymers synthesized from the lower‐molecular‐weight prepolymer were significantly higher than for those synthesized from the higher‐molecular‐weight prepolymer. Higher crystallinity and lamellar thickness may lower the reaction rate by reducing chain‐end mobility, effectively reducing the rate constant for the reaction of end groups. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4959–4969, 2008
Fluorinated benzoxazines and the structure‐property relationship of resulting polybenzoxazines
Authors: Lin Ching Hsuan , Chang Sheng Lung , Lee Hao Hsin , Chang Hou Chien , Hwang Kuen Yuan , Tu An Pang , Su Wen Chiung
Published: June 2008

Three fluorinated benzoxazines (14–16), which cannot be synthesized by the traditional one‐step approaches, were synthesized by a three‐step procedure using fluorinated aromatic diamines (2–4) as starting materials. The structures of the monomers were confirmed by 1H NMR, IR, and high‐resolution mass spectra. The low dielectric thermosets, P(14–16), were prepared by ring‐opening of (14–16). IR analysis was utilized to monitor the ring‐opening reaction of (14–16) and to propose the structures of P(14–16). The thermal and dielectric properties of P(14–16) were studied and compared with a nonfluorinated polybenzoxazine P(13), which is derived form the ring‐opening of 2,2‐bis(4‐aminophenoxy)phenyl)propane (1). Besides, the structure–property relationship of the P(13–16) is discussed. According to Tg measurement, the ortho‐positioned CF3 substituents impart greater steric hindrance for ring‐opening of benzoxazines than CF3 substituents of hexafluoropropane. Incorporating a biphenol F‐based benzoxazine, (F‐a), into fluorinated benzoxazines (15–16) can dilute the effect of ortho‐positioned CF3 substituents on steric hindrance, leading to a higher crosslinking density and consequently a higher Tg. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4970–4983, 2008
Facile synthesis of controlled‐structure primary amine‐based methacrylamide polymers via the reversible addition‐fragmentation chain transfer process
Authors: Deng Zhicheng , Bouchékif Hassen , Babooram Keshwaree , Housni Abdelghani , Choytun Nankishoresing , Narain Ravin
Published: June 2008

We report here a novel direct method for the syntheses of primary aminoalkyl methacrylamides that requires mild reagents and no protecting group chemistry. The reversible addition‐fragmentation chain transfer polymerization (RAFT) of the aminoalkyl methacrylamide revealed to be highly efficient with 4‐cyanopentanoic acid dithiobenzoate (CTP) as chain transfer agent and 4,4′‐azobis(4‐cyanovaleric acid) (ACVA) as initiator. Cationic amino‐based homopolymers of reasonably narrow polydispersities (Mw/Mn < 1.30) and predetermined molecular weights were obtained without recourse to any protecting group chemistry. A range of block and random copolymers were also synthesized via the RAFT process. The homopolymers and copolymers were characterized by aqueous conventional and triple detection gel permeation chromatography systems. Furthermore, the primary amine‐based methacrylamide monomers and polymers revealed to be highly stable both with the primary amino group in the protonated and deprotonated form. We have also demonstrated that stabilized gold nanoparticles can be generated with the RAFT‐synthesized amine‐based polymers via a photochemical process. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4984–4996, 2008
Synthesis of adaptative and amphiphilic polymer model conetworks by versatile combination of ATRP, ROP, and “Click chemistry”
Authors: Mespouille Laetitia , Coulembier Olivier , Paneva Dilyana , Degée Philippe , Rashkov Iliya , Dubois Philippe
Published: June 2008

Well‐defined adaptative and amphiphilic polymer conetworks based on hydrophilic poly(N,N‐dimethylamino‐2‐ethyl methacrylate) (PDMAEMA) and hydrophobic poly(ε‐caprolactone) (PCL) have been prepared by combination of ATRP, ROP, and “Click chemistry.” Telechelic α,ω‐alkyne terminated PCL crosslinker was obtained by ring‐opening polymerization (ROP) of CL in THF at 80 °C initiated by 1,4‐butanediol and catalyzed by tin(II) bis 2‐ethyl hexanoate (Sn(Oct)2), followed by the quantitative esterification of hydroxyl end‐groups by activated 4‐pentynoic acid. In parallel, an azido‐containing PDMAEMA‐based copolymer was obtained in a three‐step strategy involving primarily the copolymerization of DMAEMA with newly synthesized 2‐(2‐azidoethoxy)ethyl methacrylate (AEEMA) monomer. The latter was obtained by nucleophilic substitution of chloride atom from 2‐(2‐chloroethoxy)ethanol by an azide group followed by the esterification reaction of the hydroxyl group with methacrylic anhydride. The copolymerization was carried out in an equivolumic mixture of H2O and isopropanol at r.t. and initiated by a ω‐bromoisobutyryl oligo PEO macroinitiator in the presence of various ligated copper(I)‐based catalysts. In a last step, both polymer precursors were chemically linked by the Huisgen‐1,3‐dipolar cycloaddition in anhydrous THF at r.t. using CuBr complexed by 2,2′‐bipyridine ligand as catalyst. Final material was characterized by the means of DSC and SEM, both attesting of a homogeneous distribution of the PCL crosslinkers and a highly porous structure in this new amphiphilic model conetworks. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4997–5013, 2008
Tailor‐made hybrid nanostructure of poly(ethyl acrylate)/clay by surface‐initiated atom transfer radical polymerization
Authors: Datta Haimanti , Bhowmick Anil K. , Singha Nikhil K.
Published: June 2008

Hybrid nanoarchitecture of tailor‐made Poly(ethyl acrylate)/clay was prepared by surface‐initiated atom transfer radical polymerization (SI‐ATRP), by tethering ATRP initiator on active hydroxyl group, present in surface as well as in the organic modifier of the clay used. Extensive exfoliation was facilitated by using these initiator modified clay platelets. Poly(ethyl acrylate) chains with controlled polymerization and narrow polydispersities were forced to be grown from within the clay gallery (intergallery) as well as from the outer surface (extragallery) of the clay platelets. The polymer chains attached onto clay surfaces might have the potential to provide the composites with enhanced compatibility in blends with common polymers. Attachment of the initiator on clay platelets was confirmed by Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), elemental analysis, Wide‐angle X‐ray diffraction (WAXD), and microscopic analysis. Finally, end group analysis (by Matrix‐Assisted Laser Desorption Ionization Mass Spectrometry, and chain extension experiment) of the cleaved polymer and morphological study (by WAXD, Transmission Electron Microscopy), performed on the polymer grafted clays examined the effect of grafting on the efficiency of polymerization and the degree of dispersion of clay tactoids in polymer. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5014–5027, 2008
Self‐assembly of thermo‐ and pH‐responsive poly(acrylic acid)‐b‐poly(N‐isopropylacrylamide) micelles for drug delivery
Authors: Li Guiying , Song Sen , Guo Lei , Ma Songmei
Published: June 2008

Self‐assembled thermo‐ and pH‐responsive poly(acrylic acid)‐b‐poly(N‐isopropylacrylamide) (PAA‐b‐PNIPAM) micelles for entrapment and release of doxorubicin (DOX) was described. Block copolymer PAA‐b‐PNIPAM associated into core‐shell micelles in aqueous solution with collapsed PNIPAM block or protonated PAA block as the core on changing temperature or pH. Complexation of DOX with PAA‐b‐PNIPAM triggered by the electrostatic interaction and release of DOX from the complexes due to the changing of pH or temperature were studied. Complex micelles incorporated with DOX exhibited pH‐responsive and thermoresponsive drug release profile. The release of DOX from micelles was suppressed at pH 7.2 and accelerated at pH 4.0 due to the protonation of carboxyl groups. Furthermore, the cumulative release of DOX from complex micelles was enhanced around LCST ascribed to the structure deformation of the micelles. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5028–5035, 2008
β‐Cyclodextrin polymer brushes based on hyperbranched polycarbosilane: Synthesis and characterization
Authors: Tian Wei , Fan Xiao‐Dong , Liu Yu‐Yang , Jiang Min , Huang Yi , Kong Jie
Published: June 2008

In this article, our main goal is to combine hyperbranched polymer with β‐cyclodextrin (β‐CD) to establish a novel functional polymer species with core‐shell structure and supramolecular system for further application in inclusion technologies and the complex drugs delivery system. Therefore, two β‐CD polymer brushes based on hyperbranched polycarbosilane (HBP) as a hydrophobic core and poly(N,N‐dimethylaminoethyl methacrylate) (PDMA) carrying β‐CD units as a hydrophilic shell were synthesized. Hyperbranched polycarbosilane macroinitiator carrying Cl groups (HBP‐Cl) was also prepared by using 1,1,3,3‐tetrmethyldisiloxane, allyl alcohol, and chloroacetyl chloride as reagents. The molecular structures of HBP‐Cl macroinitiator and β‐CD polymer brushes were characterized by Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance (1H NMR), 13C nuclear magnetic resonance (13C NMR) spectroscopies, size exclusion chromatography/multi‐angle laser light scattering (SEC/MALLS) and laser particle size analyzer. The results indicate that the grafted chain length of two β‐CD polymer brushes can be controlled by changing the feed ratio. Differential scanning calorimetry (DSC) results show that two β‐CD polymer brushes have two glass transition temperatures (Tgs) from a hydrophobic core part and a hydrophilic shell part, respectively, and the Tg from PDMA is higher than that of HBP‐g‐PDMA. Thermalgravimetric analyzer (TGA) analysis indicates that the thermostability of two β‐CD polymer brushes is higher than that of HBP, but is lower than that of HBP‐g‐PDMA. Using phenolphthalein (PP) as a guest molecule, molecular inclusion behaviors for two β‐CD polymer brushes were studied. It reveals that two β‐CD polymer brushes possess molecular inclusion capability in PP buffer solution with a fixed concentration. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5036–5052, 2008