bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and characterization of interferon‐loaded magnetic biodegradable microspheres
Authors: Zhou Shaobing , Sun Jing , Sun Lin , Dai Yanqin , Liu Liping , Li Xiaohong , Wang Jianxin , Weng Jie , Jia Wenxiang , Zhang Zairong 
Published: April 2008

AbstractIn this work, magnetite (Fe3O4) nanoparticles with an average size 10 nm modified by sodium oleate were prepared by the modified controlled chemical coprecipitation method, which can be well dispersed in water and linked well with protein molecules because of the presence of —COOH on their surface. Then magnetic poly(lactic acid) (PLA) and poly(lactic‐co‐glycolic acid) (PLGA) microspheres containing interferon alpha‐2b (IFN‐a‐2b) were prepared by the modified water‐in‐oil‐in‐water solvent evaporation procedure. X‐ray powder diffraction analysis, particle size analysis, transmission electron microscopy, scanning electron microscopy, and vibrating‐sample magnetometer (VSM) analysis were carried out to examine phase composition, surface and interior morphology, size and size distribution, and magnetic properties of the magnetic microspheres. Also the effects of some important parameters on the magnetic biodegradable microspheres were investigated, such as magnetite dosage in the preparation system, stirring rate of the suspension medium, and concentration of the external aqueous phase. And the antiviral activity of IFN‐a‐2b encapsulated in the magnetic polymeric microspheres was evaluated by the vesicular stomatitis virus (VSV) cytopathicity inhibition assay. The results showed that the properties of IFN‐loaded magnetic PLGA and PLA microspheres were better than the conventional protein‐loaded polymeric microspheres, such as perfect magnetic properties, higher protein encapsulation efficiency, and less effect on the antiviral activity of protein. These indicated that the magnetic PLA and PLGA microspheres containing IFN‐a‐2b exhibited strong potential as targeted‐drug delivery vehicles, which could be rapidly localized to the immunization‐related tissues easily by an external magnetic field. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Cancer chemoprevention and chemotherapy: Dietary polyphenols and signalling pathways
Authors: Ramos Sonia 
Published: April 2008

AbstractPrevention of cancer through dietary intervention recently has received an increasing interest, and dietary polyphenols have become not only important potential chemopreventive, but also therapeutic, natural agents. Polyphenols have been reported to interfere at the initiation, promotion and progression of cancer. They might lead to the modulation of proteins in diverse pathways and require the integration of different signals for the final chemopreventive or therapeutic effect. Polyphenols have been demonstrated to act on multiple key elements in signal transduction pathways related to cellular proliferation, differentiation, apoptosis, inflammation, angiogenesis and metastasis; however, these molecular mechanisms of action are not completely characterized and many features remain to be elucidated. The aim of this review is to provide insights into the molecular basis of potential chemopreventive and therapeutic activities of dietary polyphenols with emphasis in their ability to control intracellular signalling cascades considered as relevant targets in a cancer preventive approach.
Fate of 14C‐acrylamide in roasted and ground coffee during storage
Authors: Baum Matthias , Böhm Nadine , Görlitz Jessica , Lantz Ingo , Merz Karl Heinz , Ternité Rüdiger , Eisenbrand Gerhard 
Published: April 2008

AbstractAcrylamide (AA) is formed during heating of carbohydrate rich foods in the course of the Maillard reaction. AA has been classified as probably carcinogenic to humans. Storage experiments with roasted coffee have shown that AA levels decrease depending on storage time and temperature. In the present study the fate of AA lost during storage of roasted and ground (R&G) coffee was studied, using 14C‐labeled AA as radiotracer. Radiolabel was measured in coffee brew, filter residue, and volatiles. In the brew, total 14C‐label decreased during storage of R&G coffee, while activity in the filter residue built up concomitantly. [2,3‐14C]‐AA (14C‐AA) was the only 14C‐related water extractable low molecular compound in the brew detected by radio‐HPLC. No formation of volatile 14C‐AA‐related compounds was detected during storage and coffee brewing. Close to 90% of the radiolabel in the filter residue (spent R&G coffee, spent grounds) remained firmly bound to the matrix, largely resisting extraction by aqueous ammonia, ethyl acetate, chloroform, hexane, and sequential polyenzymatic digest. Furanthiols, which are abundant as aroma components in roasted coffee, have not been found to be involved in the formation of covalent AA adducts and thus do not contribute substantially to the decrease of AA during storage.
Clinical, sonographic, and epidemiologic features of second‐ and early third‐trimester spontaneous antepartum uterine rupture: a cohort study
Authors: Vaknin Zvi , Maymon Ron , Mendlovic Sonia , Barel Oshri , Herman Arie , Sherman Dan 
Published: April 2008

AbstractObjectiveTo present prenatal findings and maternal and neonatal outcomes following second‐ and early third‐trimester spontaneous antepartum uterine rupture events in our institute.MethodCharts of patients with full‐thickness second‐ or early third‐trimester symptomatic uterine ruptures locally treated between 1984 and 2007 were evaluated.ResultsThere were seven events involving six women, all requiring emergency laparotomy, and cesarean section (CS). During the study period in our institute, there were 120 636 singleton deliveries (≥22 weeks' gestation), including 5 of our cases, while in 2 cases, the rupture occurred earlier (<22 weeks' gestation). The rupture occurred after ≥ 1 previous CSs in five cases. Six events were associated with abnormal placentation: placenta previa (n = 3), placenta percreta (n = 1), or both (n = 2). Other associated events included short, interpregnancy (IP) interval (n = 3) and past uterine rupture (n = 2). Pregnant women at gestational age ≥ 22 weeks, who had the combination of placenta previa, and previous CS (n = 3), had a higher chance for spontaneous symptomatic antepartum uterine rupture when compared to women with placenta previa without a previous CS (OR 29.3, 95% CI 1.5–569.3, p = 0.007). There were no maternal deaths. Three of the five viable neonates survived.ConclusionsSpontaneous symptomatic second‐ or early third‐trimester uterine rupture in nonlaboring women is a very rare, obstetric emergency, which is hard to diagnose. Maternal and neonatal outcomes can be optimized by awareness of risk factors, recognition of clinical signs and symptoms, and availability of ultrasound to assist in establishing diagnosis, and enabling prompt surgical intervention. Copyright © 2008 John Wiley & Sons, Ltd.
Review and critical analysis of the morphology of random ionomers across many length scales
Authors: Grady Brian P. 
Published: April 2008

AbstractThis review presents a description of what is known about ionomer morphology. All papers on ionomer morphology are not included in this review; but all relevant questions about ionomer morphology are posed and answered as completely as possible. The review is critical; that is, reasons are given for morphologies that are deemed to be more or less likely. The review is organized along three length scales: sub‐nanometer, nanometer to 10 nm, and greater than 10 nm. Within each length scale, all three phases are considered: crystalline, amorphous, and ionic aggregate. The purity of the three phases, the arrangement of atoms in the three phases, the size and shape of the three phases, and their arrangements in space relative to each other are explored in this review. A model for the shape of aggregates in ionomers that have well‐ordered internal environments is presented. This model proposes that aggregates are fundamentally planar, but will “roll up” into tubes or other related structures in order to reduce the number of atoms at aggregate edges. This model was developed primarily based on the varied morphologies ionomers have shown in electron micrographs, but is consistent with other indirect measurements of ionomer morphology. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.
Fluid phase behavior modeling of CO2 + molten polymer systems using cubic and theoretically based equations of state
Authors: Arce Pedro , Aznar Martin , Mattedi Silvana 
Published: April 2008

AbstractPhase equilibrium data of CO2 + molten polymer systems are of great relevance for chemical engineers because these are necessary for the optimal design of polymer final‐treatment processes. This kind of processes needs information about gas solubilities in polymers at several temperatures and pressures. In this work, CO2 solubilities in molten polymers were modeled by the perturbed chain‐statistical associating fluid theory (PC‐SAFT) equation of state (EoS). For comparison, the solubilities were also calculated by the lattice gas theory (LGT) EoS, and by the well‐known Peng‐Robinson (PR) cubic EoS. To adjust the interactions between segments of mixtures, there were used classical mixing rules, with one adjustable temperature‐dependent binary parameter for the PC‐SAFT and PR EoS, and two adjustable binary parameters for the LGT EoS. The results were compared with experimental data obtained from literature. The results in terms of solubility pressure deviations indicate that the vapor–liquid behavior for CO2 + polymer systems is better predicted by the PC‐SAFT model than by LGT and PR models. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.
Electrospinning of polyamides with different chain compositions for filtration application
Authors: Heikkilä Pirjo , Taipale Aimo , Lehtimäki Matti , Harlin Ali 
Published: April 2008

AbstractElectrospinning of several polyamides, PA6, PA66, PA612, PA614, PA1012, and PA1014, having different chain compositions and lengths of diacid and diamine segments, was demonstrated. Electrospinnability and fiber production rate of these polyamides were evaluated. Electrospun fibers were characterized with regard to their use in air filtration by measuring fiber diameter and filtration efficiency of fiber coating. Longer nonpolar chain segments of higher polyamides could in theory indicate higher dielectricity compared to PA6 and PA66, which would be an advantage in filtration applications. The solubility in polar formic acid and electrospinnability of higher polyamides, on the other hand, were clearly impaired with increased length of chain segments. Hence, PA66 is our best choice, and PA612 and PA6 our second options for commercial filtration applications if fiber electrospinnability, production rate, fiber diameter, and its distribution are concerned. Filtration efficiency of more than 95% of the particles having a diameter of 0.16 μm and above was achieved with 0.5 g/m2 coating of PA66 nanofibers. Further increase in coating weight mainly increased the pressure drop to an unusable range without a significant further improvement of filtration efficiency. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.
Rheological properties, flow visualization and extrudate swell of NR compound by rotating‐die rheometer
Authors: Intawong N.‐T. , Wongchaleo C. , Sombatsompop N. 
Published: April 2008

AbstractAn experimental apparatus coupled with a rotating die system was especially designed and manufactured to study the rheological properties, flow patterns and swelling behavior of natural rubber (NR) compound for different shear rates and die rotating speeds at a test temperature of 110°C, the results being compared with those by the static capillary die. It was found that NR compound used exhibited psuedoplastic non‐Newtonian behavior. The rotation of the capillary die could reduce the extrusion load. The wall shear stress for any given shear rates increased with increasing die rotating speed. The fluctuation of the entrance pressure drop increased with increasing die rotating speed. The flow pattern development in the rotating‐die rheometer was different from that observed in the static die. The flow patterns in the rotating die were clearly unstable and contained two flow components which included axial flow along the barrel and circumferential flow at the die entrance. The size and shape of the axial and circumferential flows were more dependent on the piston displacement. It was found that the swelling ratio of the NR compound decreased with increasing die rotating speed. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.
Super‐ductile PBT alloy with excellent heat resistance
Authors: Hashima Kazuhiro , Usui Kazuhiro , Fu Luxiang , Inoue Takashi , Fujimoto Ken‐ichiro , Segawa Kentaro , Abe Tomiya , Kimura Hitoshi 
Published: April 2008

AbstractA super‐ductile PBT alloy with excellent heat resistance was successfully fabricated by reactive blending of poly(butylene terephthalate) (PBT) with poly(ethylene‐co‐glycidyl methacrylate) together with linear low density polyethylene (LLDPE) and hydrogenated styrene‐butadiene‐styrene block copolymer (SEBS). It possesses a unique tensile stress–strain curve with no yielding point and large elongation at break, moreover, the alloy did not show serious deterioration of the mechanical properties by high temperature annealing at 150°C for 96 h. The structure‐properties relationship is discussed on the basis of transmission electron microscopy, differential scanning calorimetry, dynamic mechanical analysis, and wide‐angle X‐ray diffraction analysis. The outstanding ductile nature seems to come from the negative pressure effect of LLDPE (or LLDPE/SEBS) particles that dilates the PBT ligament matrix to enhance the local segment motions. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.
Preparation and thermo‐mechanical properties of heat‐resistant epoxy/silica hybrid materials
Authors: Yang Peng , Wang Guoqing , Xia Xue , Takezawa Yoshitaka , Wang Haitao , Yamada Shinji , Du Qiangguo , Zhong Wei 
Published: April 2008

AbstractDiglycidyl ether of bisphenol‐A (DGEBA) based epoxy/silica hybrid materials filled with various amounts of 3‐glycidoxypropyltrimethoxysilane (GPTMS) and silica nanoparticles were prepared, using 4,4′‐diaminodiphenyl sulfone (DDS) as curing agent. The obtained hybrid materials were analyzed by means of Fourier‐transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results indicated that the introduction of GPTMS and silica nanoparticles had synergistic effect. The addition of GPTMS not only ameliorated the compatibility between silica and the epoxy matrix but also increased the crosslinking density of the epoxy system; meanwhile the nano‐silica further reinforced the inorganic network of the hybrid system. Consequently, the hybrid materials showed much improved heat‐resistant properties. The storage modulus of the hybrid systems showed no obvious decrement in the glass transition region and kept at a high value even in the temperature region up to 300°C. The integral thermal stability of the resulting hybrid materials was also improved compared with the corresponding pure epoxy resin. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.
Polyurethane triblock copolymers with mono‐disperse hard segments. Influence of the hard segment length on thermal and thermomechanical properties
Authors: Arun Araichimani , Baack Kasper K.J. , Gaymans Reinoud J. 
Published: April 2008

AbstractPolyurethane triblock copolymers were synthesized by reacting 4,4′‐methylenebis(phenyl isocyanate) (MDI)‐endcapped poly(tetramethylene oxide) (PTMO) with mono‐amine‐amide (MMA) units. Four different MMA units were used, i.e. no‐amide (6m), mono‐amide (6B), di‐amide (6T6m) and tri‐amide (6T6B), based on hexylamine (6m), 1,6‐hexamethylenediamine (6), terephthalic acid (T), and benzoic acid (B). The PTMO had a molecular weight of 2000 g/mol. Thermal and thermo‐mechanical properties were studied by means of differential scanning calorimetry and dynamic mechanical analysis, respectively. The structure of the carbonyl bond was explored by infra‐red analysis and the elastic behavior of the materials by compression set experiments. The triblock polyurethanes with mono‐disperse, hard end‐segments displayed low molecular weights (3200–3800 g/mol). The crystallinity of the MDI urethane‐urea group was found to depend on the structure of the amide. Increasing the number of amide bonds in the mono‐disperse hard segment increased the modulus and the hard segment melting temperature, and decreased the compression set values. The low temperature properties were hardly affected by the amide length. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.
Atom transfer radical polymerization of hexyl acrylate and preparation of its “all‐acrylate” block copolymers
Authors: Datta Haimanti , Singha Nikhil K. 
Published: April 2008

AbstractThis investigation reports the polymerization of hexyl acrylate (HA) using atom transfer radical polymerization technique and subsequently the preparation of its di‐ and triblock copolymers with methyl methacrylate. Atom transfer radical polymerization of HA was investigated using different initiators and CuBr or CuCl as catalyst in combination with varying ligands, e.g., 2,2′‐bipyridine and N,N,N′,N″,N″‐pentamethyl diethylenetriamine. Reaction parameters were adjusted to successfully polymerize HA with well‐defined molecular weights and narrow polydispersity indices. The polymerization was better controlled by the addition of polar solvents, which created a homogeneous catalytic system. UV–vis analysis showed that the polar solvent, acetone coordinated with copper (I), changes the nature of the copper catalyst, thereby influencing the dynamic equilibrium of activation–deactivation cycle. This resulted in improved control over polymerization as well as in lowering the polydispersity indices, but at the cost of polymerization rate compared with the bulk process. The presence of Br end group in the polymer chains was confirmed by 1H NMR as well as MALDI‐TOF mass analysis. In addition, poly(hexyl acrylate) was used as macroinitiator to prepare various “all‐acrylate” block (diblock, triblock) copolymers that were characterized by GPC and 1H NMR. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3499–3511, 2008
Thermally curable polyvinylchloride via click chemistry
Authors: Kiskan Baris , Demiray Güniz , Yagci Yusuf 
Published: April 2008

AbstractNovel side‐chain benzoxazine functional polyvinylchloride (PVC‐Benzoxazine) was synthesized by using “Click Chemistry” strategy. First, approximately 10% of chloro groups of PVC were converted to azido groups by using NaN3 in N,N‐dimethylformamide. Propargyl benzoxazine was prepared independently by a ring closure reaction between p‐propargyloxy aniline, paraformaldehyde, and phenol. Finally, azidofunctionalized PVC was coupled to propargyl benzoxazine with high efficiency by click chemistry. The spectral and thermal analysis confirmed the presence of benzoxazine functionality in the resulting polymer. It is shown that PVC containing benzoxazine undergoes thermally activated curing in the absence of any catalyst forming PVC thermoset with high thermal stability. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3512–3518, 2008
Aggregates of amphiphilic fluorinated copolymers and their encapsulating and unloading homopolymer behaviors
Authors: Xu Shouping , Liu Weiqu 
Published: April 2008

AbstractAmphiphilic fluorinated block copolymers synthesized via reversible addition‐fragmentation chain transfer polymerization were used for the preparation of aggregates of various morphologies. First, dissolve the copolymer in 2‐butanone; second, add a precipitant solvent, which was the mixture of water and methanol, to induce the aggregation of the hydrophobic fluorinated block. With a hydrophilic tail and a very hydrophobic segment, these copolymers are likely to self‐assemble in solution and form aggregates. Observed by TEM, spheres, rods, and vesicles can be formed by changing the precipitant mixture contents. Besides, these aggregates were found to be able to carry hydrophobic fluorinated homopolymers, and two suggested processes have been proposed to explain their morphology changes from original spheres, rods and vesicles into larger size spheres. Finally, hollow bilayer spheres and tubules can be achieved after extracting homopolymers in the center of the newly formed spheres. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1000–1006, 2008
Effects of maternal retinoic acid administration in a congenital diaphragmatic hernia rabbit model
Authors: Gallot Denis , Coste Karen , Jani Jacques , Roubliova Xenia , Marceau Geoffroy , Velemir Luka , Verheyen An , Lemery Didier , Sapin Vincent , Deprest Jan 
Published: April 2008

AbstractMaternal retinoid administration has beneficial effects on lung development in the nitrofen rodent toxic model of congenital diaphragmatic hernia (DH). We wanted to investigate the effects in a surgical model, where the retinoid signaling pathway is not primarily disrupted by the toxic agent. We created DH in fetal rabbits at day 23 of gestation, administrated to the does all trans‐retinoic acid (ATRA) or vehicle (VHC) intramuscularly for 8 consecutive days and harvested normal and operated (DH) fetuses at 31 d (n = 7 in each group). Normal lungs exposed to ATRA had increased surfactant protein mRNA levels without change in type II pneumocyte density. There was no measurable effect on lung‐to‐body weight ratio and airway morphometry by ATRA. In DH lungs (DH/VHC) surfactant protein mRNA levels were increased, as well as the density of type II pneumocytes. When supplemented with ATRA (DH/ATRA) these parameters returned to normal (VHC). Cell proliferation or apoptosis were not influenced by ATRA supplementation. In conclusion, maternal ATRA supplementation does not affect gross anatomic, morphologic or proliferation indices in hypoplastic lungs related to surgically induced DH in rabbit. However, ATRA lowers surfactant protein expression and normalizes type I/II pneumocyte ratio to what is observed in normal lungs. Pediatr Pulmonol. 2008; 43:594–603. © 2008 Wiley‐Liss, Inc.
Determination of the 15N/14N, 17O/16O, and 18O/16O ratios of nitrous oxide by using continuous‐flow isotope‐ratio mass spectrometry
Authors: Komatsu Daisuke D. , Ishimura Toyoho , Nakagawa Fumiko , Tsunogai Urumu 
Published: April 2008

AbstractWe developed a rapid, sensitive, and automated analytical system to determine the δ15N, δ18O, and Δ17O values of nitrous oxide (N2O) simultaneously in nanomolar quantities for a single batch of samples by continuous‐flow isotope‐ratio mass spectrometry (CF‐IRMS) without any cumbersome and time‐consuming pretreatments. The analytical system consisted of a vacuum line to extract and purify N2O, a gas chromatograph for further purification of N2O, an optional thermal furnace to decompose N2O to O2, and a CF‐IRMS system. We also used pneumatic valves and pneumatic actuators in the system so that we could operate it automatically with timing software on a personal computer. The analytical precision was better than 0.12‰ for δ15N with >4 nmol N2O injections, 0.25‰ for δ18O with >4 nmol N2O injections, and 0.20‰ for Δ17O with >20 nmol N2O injections for a single measurement. We were also easily able to improve the precision (standard errors) to better than 0.05‰ for δ15N, 0.10‰ for δ18O, and 0.10‰ for Δ17O through multiple analyses with more than four repetitions with 190 nmol samples using the automated analytical system. Using the system, the δ15N, δ18O, and Δ17O values of N2O can be quantified not only for atmospheric samples, but also for other gas or liquid samples with low N2O content, such as soil gas or natural water. Here, we showed the first ever Δ17O measurements of soil N2O. Copyright © 2008 John Wiley & Sons, Ltd.