bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fetal eyeball volume: relationship to gestational age and biparietal diameter
Authors: Odeh Marwan , Feldman Yulia , Degani Shimon , Grinin Vitali , Ophir Ella , Bornstein Jacob 
Published: April 2009

AbstractObjectiveTo measure and determine normal values of the fetal eyeball volume between 14 and 40 weeks of gestation.MethodsThe volume of the fetal eyeball was measured with three‐dimensional ultrasound between 14 and 40 weeks of gestation using the VOCAL software.Only singleton pregnancies without fetal growth restriction, diabetes mellitus, hypertension or major fetal malformation were included.ResultsOver all, 203 women were studied. In 125 both eyeballs were measured while in 78 only one eyeball was measured. The volume of the eyeball correlated strongly with gestational age (right: R = 0.946, P < 0.001, n = 171. left: R = 0.945, P < 0.001, n = 156), and with the biparietal diameter (BPD) (right: R = 0.949, P < 0.001, n = 171. left: R = 0.953, P < 0.001, n = 156). Using regression analysis the best correlation between eyeball volume and the BPD were: square of right eyeball = −0.180 + 0.187 BPD, square of left eyeball = −0.182 + 0.187 BPD.ConclusionsThe volume of the eyeball has strong positive correlations with gestational age and BPD. Our data may be helpful in fetuses suspected of having eye anomalies. Copyright © 2009 John Wiley & Sons, Ltd.
Facile and efficient preparation of phosphinate‐functionalized aromatic diamines and their high‐Tg polyimides
Authors: Chang Chia Wei , Hsuan Lin Ching , Wen Cheng Po , Hwang Hann Jang , Dai Shenghong A. 
Published: April 2009

AbstractTwo novel phosphorus‐functionalized aromatic diamines, 1,1‐bis(4‐aminophenyl)‐1‐(6‐oxido‐6H‐dibenz <c,e> <1,2> oxaphosphorin‐6‐yl)ethane (1) and bis(4‐aminophenyl)‐(6‐oxido‐6H‐dibenz <c,e> <1,2> oxaphosphorin‐6‐yl)phenylmethane (2), were prepared from 9,10‐dihydro‐oxa‐10‐phosphaphenanthrene‐10‐oxide, 4‐aminoacetophenone, or 4‐aminobenzophenone in excess aniline using p‐toluenesulfonic acid monohydrate as catalyst by an efficient, one‐pot procedure. The effect of electron withdrawing/donating groups on the stabilization of the resulting carbocation seems critical for the success of the process and was discussed in detail. Based on diamines (1–2), a series of new polyimides, (5a–5d) and (6a–6d), were prepared, respectively. Polyimides (5a–5d) are flexible and creasable. In contrast, polyimides (6a–6d) are brittle because of the structure rigidity, according to the analysis based on the NMR temperature‐dependent spectra of (2). Polyimides 5 displaying high Tg (318–392 °C), high moduli (3.39–4.49 GPa), low coefficient of thermal expansion (42–50 ppm/°C), and moderate thermal stability (Td 5 wt % at 426–439 °C), are excellent high‐Tg and flame‐retardant materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2486–2499, 2009
Chiral polyamides consisting of N‐α‐benzoyl‐L‐glutamic acid as a diacid component
Authors: Ikeuchi Yoshimi , Nakagawa Maiko , Yoshikawa Masakazu , Yoshida Hidekazu , Sakurai Shinichi 
Published: April 2009

AbstractNovel polyamide with chiral environment was obtained from aromatic diamine, 4,4′‐diaminodiphenylmethane (DADPM), and N‐α‐protected L‐glutamic acid, N‐α‐benzoyl‐L‐glutamic acid (Benzoyl‐L‐Glu‐OH). The optical rotation ([α]D) of the polyamide was determined to be 3.6° (c = 1.00 g/dL in DMF), implying that the optically active polyamide was obtained. The present polyamide gave a durable self‐standing membrane. The membrane selectively incorporated the D‐isomer of Ac‐Trp from racemic mixture of Ac‐Trp. The adsorption selectivity toward Ac‐D‐Trp was determined to be 1.95. It showed chiral separation ability by adopting potential difference as a driving force for membrane transport. The permselectivity was dependent on the potential difference, and at the applied potential difference of 3.0 V, the membrane selectively transported Ac‐D‐Trp and the permselectivity toward Ac‐D‐Trp was determined to be 1.84, which was close to the adsorption selectivity of 1.95. Contrary to this, the membrane showed opposite permselectivity at the applied potential difference of 2.0 V and the permselectivity toward the L‐isomer reached 2.48. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2530–2538, 2009
Heterotactic‐specific radical polymerization of N‐isopropylacrylamide and phase transition behavior of aqueous solution of heterotactic poly(N‐isopropylacrylamide)
Authors: Hirano Tomohiro , Kamikubo Takahiro , Okumura Yuya , Bando Yoichi , Yamaoka Ryosuke , Mori Takeshi , Ute Koichi 
Published: April 2009

AbstractRadical polymerization of N‐isopropylacrylamide (NIPAAm) in toluene at low temperatures, in the presence of fluorinated‐alcohols, produced heterotactic polymer comprising an alternating sequence of meso and racemo dyads. The heterotacticity reached 70% in triads when polymerization was carried out at −40 °C using nonafluoro‐tert‐butanol as the added alcohol. NMR analysis revealed that formation of a 1:1 complex of NIPAAm and fluorinated‐alcohol through CO···HO hydrogen bonding induces the heterotactic specificity. A mechanism for the heterotactic‐specific polymerization is proposed. Examination of the phase transition behavior of aqueous solutions of heterotactic poly(NIPAAm) revealed that the hysteresis of the phase transition between the heating and cooling cycles depended on the average length of meso dyads in poly(NIPAAm). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2539–2550, 2009
Vinyl addition polymerization of norbornene with cationic (allyl)Ni catalysts: Mechanistic insights and characterization of first insertion products
Authors: Walter Marc D. , Moorhouse Rebecca A. , White Peter S. , Brookhart Maurice 
Published: April 2009

AbstractSeveral cationic (allyl)Ni(II) complexes were synthesized and shown to be highly active for (2,3)‐vinyl addition polymerization of norbornene to yield polymers with low molecular weight distributions (MWDs) ranging from 1.4–1.9. In all cases slow initiation was followed by rapid propagation which prevents molecular weight control of the poly(norbornene). One of the intermediates in the polymerization process has been identified and characterized by NMR spectroscopy as the first insertion product resulting from the insertion of norbornene into the NiC allyl bond in cis‐exo fashion. This insertion product was synthesized independently and NMR studies showed that the first insertion of norbornene into the NiC allyl bond is a reversible process. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2560–2573, 2009
Incorporating glycidyl methacrylate into block copolymers using poly(methacrylate‐ran‐styrene) macroinitiators synthesized by nitroxide‐mediated polymerization
Authors: Lessard Benoît , Marić Milan 
Published: April 2009

AbstractMethyl methacrylate/styrene (MMA/S), ethyl methacrylate/styrene (EMA/S) and butyl methacrylate/styrene (BMA/S) feeds (>90 mol % methacrylate) were copolymerized in 50 wt % p‐xylene at 90 °C with 10 mol % of additional SG1‐free nitroxide mediator relative to unimolecular initiator (BlocBuilder®) to yield methacrylate rich copolymers with polydispersities $\overline{M}$w/$\overline{M}$n = 1.23–1.46. kpK values (kp = propagation rate constant, K = equilibrium constant) for MMA/S copolymerizations were comparable with previous literature, whereas EMA/S and BMA/S copolymerizations were characterized by slightly higher kpK's. Chain extensions with styrene at 110 °C initiated by the methacrylate‐rich macroinitiators (number average molecular weight $\overline{M}$n = 12.9–33.5 kg mol−1) resulted in slightly broader molecular weight distributions with $\overline{M}$w/$\overline{M}$n = 1.24–1.86 and were often bimodal. Chain extensions with glycidyl methacrylate/styrene/methacrylate (GMA/S/XMA where XMA = MMA, EMA or BMA) mixtures at 90 °C using the same macroinitiators resulted frequently in bimodal molecular weight distributions with many inactive macroinitiators and higher $\overline{M}$w/$\overline{M}$n = 2.01–2.48. P(XMA/S) macroinitiators ($\overline{M}$n = 4.9–8.9 kg mol−1), polymerized to low conversion and purified to remove “dead” chains, initiated chain extensions with GMA/MMA/S and GMA/EMA/S giving products with $\overline{M}$w/$\overline{M}$n ∼ 1.5 and much fewer unreacted macroinitiators (<5%), whereas the GMA/BMA/S chain extension was characterized by slightly more unreacted macroinitiators (∼20%). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2574–2588, 2009
Synthesis of exact comb polybutadienes with two and three branches
Authors: Nikopoulou Anastasia , Iatrou Hermis , Lohse David J. , Hadjichristidis Nikos 
Published: April 2009

AbstractTwo methodologies, based on living star polymers and anionic polymerization high vacuum techniques, were used for the synthesis of exact comb polybutadienes (PBds) with two (C‐2 or H‐type) and three identical branches (symmetric, sC‐3, H‐type with an extra identical branch at the middle of the connector and asymmetric, aC‐3, H‐type with the extra identical branch at any other position along the connector). The first methodology involves (a) the selective replacement of the two chlorines of 4‐(dichloromethylsilyl)diphenylethylene (DCMSDPE, key molecule) with 3‐arm star PBds, by titration with identical (C‐2, sC‐3) or different (aC‐3) living 3‐arm star PBds, (b) the addition of s‐BuLi to the double bond of DPE, and (c) the polymerization of butadiene from the newly created anionic site (sC‐3, aC‐3).The second methodology involves the reaction of living stars with dichlorodimethylsilane (C‐2) or the selective replacement of the three chlorines of trichloromethylsilane with star and linear chains (sC‐3, aC‐3). Intermediate and final products were characterized via size exclusion chromatography, low angle laser light scattering and 1H‐NMR. The first methodology does not require fractionation, but in contrast to the second methodology, cannot afford polymers with branches of identical molecular weight. Both methods are general and can be extended to combs with two or three different branches at controllable positions along the backbone. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2597–2607, 2009
An efficient synthetic route to well‐defined theta‐shaped copolymers
Authors: Shi Gang‐Yin , Pan Cai‐Yuan 
Published: April 2009

AbstractA series of well‐defined θ‐shaped copolymers composed of polystyrene (PS) and poly(ε‐caprolactone) (PCL) with controlled molecular weight and narrow molecular weight distribution have been successfully synthesized without any purification procedure by the combination of atom transfer radical polymerization (ATRP), ring‐opening polymerization (ROP), and the “click” chemistry. The synthetic process involves two steps: (1) synthesis of AB2 miktoarm star copolymers, which contain one PCL chain terminated with two acetylene groups and two PS chains with two azido groups at their one end, (α,α′‐diacetylene‐PCL) (ω‐azido‐PS)2, by ROP, ATRP, and the terminal group transformation; (2) intramolecular cyclization of AB2 miktoarm star copolymers to produce well‐defined pure θ‐shaped copolymers using “click” chemistry under high dilution. The 1H NMR, FTIR, and gel permeation chromatography techniques were applied to characterize the chemical structures of the resultant intermediates and the target polymers. Their thermal behavior was investigated by DSC. The mobility decrease of PCL chain across PS ring in the theta‐shaped copolymers restricts the crystallization ability of PCL segment. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2620–2630, 2009
Catalyst‐free synthesis of polyorganosiloxanes by high temperature and pressure water. II. Understanding of the reaction process
Authors: Ogawa Takuya , Watanabe Jun , Oshima Yoshito 
Published: April 2009

AbstractA catalyst‐free polysiloxane synthetic process that uses high temperature and pressure water for the hydrolysis and subsequent polycondensation of phenyltrimethoxysilane was studied in detail to gain insights into the reaction mechanism. It was suggested that this process is essentially composed of two stages: (1) oligomerization of phenyltrimethoxysilane yielding low‐molecular weight species with high contents of silanol and methoxy groups and (2) polycondensation of the oligomers yielding high‐molecular weight species. The use of a preformed oligosiloxane as a starting material was informative to understand the polycondensation stage. A modified synthetic process in which a stop valve was introduced to control the internal pressure was developed based on the understanding of the present process. This modified process enabled a two‐stage reaction resulting in a discernible increase of the molecular weight of polysiloxane. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2656–2663, 2009
(Meth)acrylate‐based photoelastomers as tailored biomaterials for artificial vascular grafts
Authors: Baudis Stefan , Heller Christian , Liska Robert , Stampfl Juergen , Bergmeister Helga , Weigel Guenter 
Published: April 2009

AbstractCardiovascular disease is one of the leading causes of morbidity and mortality in the western hemisphere. Currently available synthetic vascular conduits, like Dacron or ePTFE show excellent long‐term results for large‐caliber arterial reconstruction (aorta, iliac vessels) but when used for small diameter (<4 mm) vessel reconstruction, patency rates are extremely poor. We therefore aim at developing suitable blood vessel substitutes out of biocompatible photopolymer formulations, which can be printed by rapid prototyping. Rapid prototyping offers the possibility to create cellular structures within the grafts that favor the ingrowth of tissue. To meet the high requirements for artificial biomaterials, it is necessary to develop new resin formulations. Beside the biocompatibility, the mechanical properties—a low elastic modulus (500 kPa) at a relatively high tensile strength (1.0 MPa) and a high strain at break (130%)—play a central role. Resin systems containing cyanoethyl acrylate have shown to be highly reactive, have good mechanical properties and sufficient in vitro biocompatibility. Elastic modulus and tensile strength which should be similar to natural blood vessels were adjusted by the ratio of acrylate‐based crosslinkers and—in case of hydrogels —the percentage of water. Finally, we were able to print small diameter conduits by microstereolithography. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2664–2676, 2009
Rheology and morphology change with temperature of SEBS/hydrocarbon oil blends
Authors: Sugimoto Masataka , Sakai Keisuke , Aoki Yuji , Taniguchi Takashi , Koyama Kiyohito , Ueda Toshihiro 
Published: April 2009

AbstractThe effect of hydrocarbon oil incorporation on the rheological and phase behaviors of poly(styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene) (SEBS) has been investigated. SEBS‐A1 (neat SEBS) shows a presence of very long relaxation time mode even at the highest temperature carried out here. On the other hand, G′ of SEBS‐A3 (oil concentration = 50 wt %) drastically decreases with increase of temperature at a critical temperature, which can be assigned to be order–disorder transition (ODT). The critical temperature was determined by two rheological criteria. Incorporation of hydrocarbon oil affects the ODT temperature. The rheological response is very sensitive to a few temperature increases around the ODT temperature. Above the critical temperature, G′ finally yields the terminal flow in the low frequency range. The morphological observation at various temperatures was determined using atomic force microscopy (AFM) equipped with environmental controller. This enabled in situ observation of structural change of SEBS induced by temperature and phase transition. We found that the layered texture, mostly aligned along the surface can be seen for SEBS‐A1 ranging from room temperature to 230 °C, though the image contrast reduced by an increase of temperature. SEBS‐A3 showed sphere domains at room temperature and also remains the structure at a critical temperature. The phase separated structure disappeared almost completely above ODT temperature, which was confirmed by the rheologial criteria. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 955–965, 2009
Eutectic crystallization and hydrogen bonding interactions in polymer/surfactant blends
Authors: Liu Jing , Hameed Nishar , Guo Qipeng 
Published: April 2009

AbstractThe unusual eutectic crystallization behavior in the poly(ε‐caprolactone) (PCL) and 3‐pentadecylphonel (PDP) binary blends was investigated by differential scanning calorimetry and Fourier transform infrared (FTIR) spectroscopy. A eutectic system was found with the eutectic composition at 60 wt % PDP and the eutectic melting temperature at 35 °C. The melting process of the blend at the eutectic composition was studied by in situ FTIR. The concurrence of the melting of PCL and PDP crystallites and the sequential formation of hydrogen bonding interaction between PDP molecules and PCL chains were traced. It was also found that a further increase in temperature above the eutectic melting temperature would impair the hydrogen bonding and increase the content of nonassociated phenol hydroxyl group. The semicrystalline morphology of blends affected by the composition was also investigated. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1015–1023, 2009
Orientation behavior of attapulgite nanoparticles in poly(acrylonitrile)/attapulgite solutions by rheological analysis
Authors: Yin Han , Mo Di , Chen Dajun 
Published: April 2009

AbstractNanocomposites based on poly(acrylonitrile) (PAN) and attapulgite (AT) had been prepared by solution blending in dimethyl sulfoxide (DMSO). The rheological properties of the nanocomposites solutions were investigated by HAAKE rheometer with plate‐cone geometry. The steady and oscillation shear experiments were carried out to investigate the effects of clay exfoliation and orientation as well as polymer‐clay interaction. The presence of small amount of AT nanoparticles with large aspect ratio improved the fluidity of these PAN solutions under low shear rate, whereas large amount of AT will reduce its aspect ratio by aggregation and constrain the polymer segment motion in the solutions. The relaxation and disentanglement behaviors of the PAN chains in nanocomposite solutions were also studied by oscillation and thixotropic experiments, from which, it can be concluded that well dispersed and oriented AT nanorods will reduce interaction among macromolecules. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 945–954, 2009
Equations of state for polyamide‐6 and its nanocomposites. II. Effects of clay
Authors: Utracki L. A. 
Published: April 2009

AbstractThe pressure‐volume‐temperature (PVT) dependencies of polyamide‐6 and its nanocomposites (polymeric nanocomposites) were measured at temperatures T = 300–600 K and pressures P = 0.1–190 MPa, thus spanning the range of molten and “solid” phases. The Simha‐Somcynsky (S‐S) cell‐hole equation of state (EOS) was used for describing the molten region. At Tg(P) ≤ T ≤ Tm(P), the “solid” phase is a mixture of the liquid polyamide‐6 with dispersion of crystals. Accordingly, the PVT behavior in this region was described as a combination of the S‐S EOS for the liquid phase and the Midha‐Nanda‐Simha‐Jain (MNSJ) EOS for the crystalline one. These two theories based on different models yielded two sets of the characteristic reducing parameters, P*, T*, V* and the segmental molecular weight, Ms. Incorporation of 2 and 5 wt % clay increased P* and reduced T* and V*, but the effects were small. Fitting the combination of S‐S and MNSJ EOS' to isobaric “solid” phase data yielded the total crystallinity, Xcryst, and the correcting excess specific volume, ΔVm,c. Both parameters were sensitive to pressure, P, and the clay content, w—the former increased with P and w, whereas the latter decreased. The raw PVT data were numerically differentiated to obtain the thermal expansion and compressibility coefficients, α and κ, respectively. At T < Tm, addition of clay reduced their relative magnitude, whereas at T > Tm, the opposite effect was observed, most likely owing to the excess of intercalant in the polymeric nanocomposites samples. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 966–980, 2009
Influence of chromophore concentration and network structure on the photo‐orientation properties of crosslinked epoxy‐based azopolymers
Authors: Fernández R. , Mondragon I. , Galante M. , Oyanguren P. 
Published: April 2009

AbstractAn azo prepolymer (TAZ) was synthesized by reaction between Disperse Orange‐3 (DO3) and diglycidyl ether of bisphenol A (DGEBA). Selected amounts of TAZ were blended with DGEBA and cured with an aliphatic diamine, either meta‐xilylenediamine (MXDA) or polyetheramines (Jeffamine D series). The photoinduced anisotropy and optical storage properties in two series of crosslinked epoxy‐based azo polymers with different architectures and chromophore contents (from 3 to 24 in weight) have been investigated. Measurements of the birefringence (Δn) induced with linearly polarized 488 nm light show that the Δn values increases with DO3 weight fraction. Networks with the same chromophore concentration but different backbones exhibit similar levels of induced anisotropy under the same irradiation conditions. The remaining birefringence and relaxation times are influenced by the molecular weight between crosslinks $ \overline {M_c} $ of networks. Higher $ \overline {M_c} $ is reflected in shorter relaxation times and lower remaining birefringence. In terms of the level of induced dichroism measured on relaxed films, it was found an agreement with the remaining anisotropy. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1004–1014, 2009
Interest in a psycho‐educational group intervention among out‐patients with malignant melanoma in relation to their need: which patients are likely to participate?
Authors: Winzer Alexandra , Hoppe Annekatrin , Altenhoff Jürgen , Kuwert Christoph , Koch Uwe , Schulz Holger 
Published: April 2009

AbstractThe aim of this study was to examine the interest which patients with malignant melanoma may have in a six week psycho‐educational group intervention and determine factors that are associated with their degree of interest. Of 144 outpatients, 121 (84%) agreed to participate in the interview (78 women, 66 men, mean age 59, SD=15; mean time since surgery=57 months, SD=55). About one‐third (29%) of the sample had either nodal or in‐transit metastases. A semi‐structured interview was conducted to assess patients' interest (perceived need) in the intervention. We administered the Hornheide questionnaire and other psychosocial measures to identify highly distressed patients (expert‐defined need). Lower age, being male, having no partner and lower cognitive avoidance emerged as significant predictors for a general interest in the intervention (n=92). A substantial number of patients (42.5%) stated a willingness to participate in the intervention at that time. Two problematic subgroups could be identified in the sample: patients in an expert‐defined need of support who lacked any interest (‘avoiders’) and interested patients without an expert‐defined need (‘skilled help‐seekers’). In order to achieve consistent results when conducting future interventions, the interventions should either be limited to patients with expert‐defined need or patients should be carefully controlled for this variable. Copyright © 2009 John Wiley & Sons, Ltd.