bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of the behavior of polyester concretes containing ionomers as curing agents
Authors: Ignacio Carlos , Ferraz Vany , Oréfice Rodrigo L. 
Published: February 2008

AbstractPolyester concretes have been used in constructions for more than 20 years. This type of polymer concrete can advantageously replace traditional Portland concrete in situations that require fast consolidation of the material. Otherwise, polyester concretes are usually more expensive than Portland concretes. Part of the high cost of the polyester concretes is due to the fact that the aggregates used in the formulation of the concretes need to be dried prior to their incorporation into the polymer matrix. In this work, the use of different curing systems (methacrylic acid and maleic anhydride) was investigated to test the hypothesis that the introduction of acid functionalities into unsaturated polyesters based on isophthalic acid could both restrict the detrimental effect of moisture in the curing process and also improve interfacial interactions even in polyester concretes containing wet aggregates. In this work, as there was no search for ways to reduce cost of polyester concretes and also to contribute to the environmental preservation, unsaturated polyesters were synthesized from PET bottles and tested in the fabrication of concretes by reacting them with a conventional curing agent (styrene). Gel permeation chromatography, infrared spectroscopy, and electron microscopy were used to monitor and analyze the production of unsaturated polyester resins and concretes. Mechanical properties were also evaluated by compression tests. Results showed that methacrylic acid and maleic anhydride, when used as curing agents, led to the production of polyester concretes having higher mechanical properties in both dry and wet states than conventional polyester (based on isophthalic acid) concretes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Rheological characterization of carbon black/polystyrene solution systems
Authors: Aoki Yuji 
Published: February 2008

AbstractSteady‐shear measurements of suspensions of carbon blacks (CB) in polystyrene (PS)/di‐(butyl phthalate) (DBP) solution were investigated as a function of volume fraction (ϕ) of CB to clarify the effect of the primary particle size and the structure of CB aggregates on the rheological properties. The suspensions show a typical shear‐thinning behavior in the range of a shear rate studied. The Casson model was applied to evaluate the viscosity at infinite of shear rate η∞ and the yield stress σy for the suspensions. Relative viscosity η∞/ηm, (ηm: medium viscosity) thus obtained was compared to the high‐frequency viscosity for the ideal hard‐sphere silica suspensions to evaluate the effective volume fraction ϕeff of CB aggregates. The ϕeff value was larger for the higher‐structure CB with higher DBP absorption value, irrespective of the primary particle size. The yield stress σy had almost the same ϕeff dependence for neutral furnace CB/(PS/DBP) suspensions, although it was larger for acetylene black (AcB)/(PS/DBP) suspensions. These results demonstrated that the effective volume fraction is the most important quantity to characterize the CB aggregates on the rheological properties. It was also found that the correction of the medium viscosity changes due to polymer adsorption on the CB surface is important since neutral furnace CB adsorbs PS polymers but AcB hardly adsorbs PS polymers in the solution. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and mechanical properties of poly(vinyl chloride)/bamboo flour composites with a novel block copolymer as a coupling agent
Authors: Kim Jeong‐Yeol , Peck Jong Hyeon , Hwang Seok‐Ho , Hong Juseok , Hong Sung Chul , Huh Wansoo , Lee Sang‐Won 
Published: February 2008

AbstractTo improve the interfacial adhesion between poly(vinyl chloride) (PVC) and bamboo flour in PVC/bamboo flour composites, a novel coupling agent, poly(styrene‐co‐maleic anhydride)‐block‐poly(styrene‐co‐acrylonitrile) {P[(SMA)‐b‐(SAN)]}, was synthesized through living free‐radical polymerization in a one‐pot reaction. P[(SMA)‐b‐(SAN)] was synthesized by a nitroxide‐mediated polymerization technique in the presence of 2,2,6,6‐tetramethylpiperidin‐l‐oxyl with azobisisobutyronitrile. The conversion of maleic anhydride (>99%) and styrene (>65%) was relatively high and yielded P[(SMA)‐b‐(SAN)] with a narrow molecular weight distribution (weight‐average molecular weight/number‐average molecular weight <1.38). PVC was blended with bamboo flours in the presence of the synthesized coupling agent with a two‐roll mill. P[(SMA)‐b‐(SAN)] was added to the PVC matrix at a concentration of 55 or 20 wt %. As the content of P[(SMA)‐b‐(SAN)] in the wood–polymer composite increased, improved morphological and mechanical behaviors were observed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of novel swelling tunable oligomeric poly(styrene‐co‐acrylamide) modified clays
Authors: Chen Ruyi , Peng Fubing , Su Shengpei 
Published: February 2008

AbstractThe oligomeric poly(styrene‐acrylamide‐vinylbenzylchloride) (P(St‐AM‐VBC)) quaternary ammonium salts have been prepared from the reactions of trimethylamine with the corresponding P(St‐AM‐VBC)s, which were synthesized by free‐radical polymerization of a mixture of styrene, acrylamide, and vinylbenzylchloride. Then the swelling tunable oligomeric poly(styrene‐co‐acrylamide) modified clays have been prepared through cation exchange of the sodium ions in the clay with the corresponding P(St‐AM‐VBC) quaternary ammonium salts. The P(St‐AM‐VBC) and its modified clays have been characterized by infrared spectra (IR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), proton nuclear magnetic resonance (1H NMR), X‐ray diffraction (XRD), and transmission electron microscopy (TEM). The solvent‐swelling capacity of poly(styrene‐co‐acrylamide) modified clays have also been tested, and the experimental results have indicated that these clays are novel swelling tunable organic clays. XRD and TEM studies have shown that these novel swelling tunable clays are well‐intercalated or exfoliated. Furthermore, TGA analysis shows that these polymerically modified clays have high thermal stability for nanocomposites by melt blending. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Information science during the first decade of the web: An enriched author cocitation analysis
Authors: Zhao Dangzhi , Strotmann Andreas 
Published: February 2008

AbstractUsing an enriched author cocitation analysis (ACA), we map information science (IS) for 1996–2005, a decade of explosive development of the World Wide Web, to examine its development since the landmark study by White and McCain (1998). The Web, we find, has had a profound impact on IS, driving the creation of new disciplines and revitalization or obsolescence of old, and most importantly, bridging the chasm between the “literatures” and “retrieval” IS camps. Simultaneously, the development of IS towards cognitive aspects has intensified. Our study enriches classic ACA in that it employs both orthogonal and oblique rotations in the factor analysis (FA), and reports both pattern and structure matrices for the latter, thus enabling a comparison between these several FA methods in ACA. Each method provides interesting information not available from the others, we find, especially when results are also visualized in the novel manner we introduce here.
Modular transporters for subcellular cell‐specific targeting of anti‐tumor drugs
Authors: Sobolev Alexander S. 
Published: February 2008

AbstractA major problem in the treatment of cancer is the specific targeting of anti‐tumor drugs to these abnormal cells. Ideally, such a drug should act over short distances to minimize damage to healthy cells, and target subcellular compartments that have the highest sensitivity to the drug. Photosensitizers, alpha‐emitting radionuclides and many other medicines could be considered as such drugs if they possessed cellular and subcellular specificity. The author describes a novel approach of using modular recombinant transporters to target photosensitizers and alpha‐emitting radionuclides to the nucleus, where their action is most pronounced, of cancer cells. Photosensitizer‐transporter conjugates have up to 3000 times greater efficacy than free photosensitizers and display cell specificity in contrast to free photosensitizers. Alpha‐emitting radionuclides, conjugated with the modular transporters, acquired similar properties. The different modules of the transporters are interchangeable, meaning that they can be tailored for particular applications. BioEssays 30:278–287, 2008. © 2008 Wiley Periodicals, Inc.
Epithelial topology
Authors: Nagpal Radhika , Patel Ankit , Gibson Matthew C. 
Published: February 2008

AbstractIt is universally accepted that genetic control over basic aspects of cell and molecular biology is the primary organizing principle in development and homeostasis of living systems. However, instances do exist where important aspects of biological order arise without explicit genetic instruction, emerging instead from simple physical principles, stochastic processes, or the complex self‐organizing interaction between random and seemingly unrelated parts. Being mostly resistant to direct genetic dissection, the analysis of such emergent processes falls into a grey area between mathematics, physics and molecular cell biology and therefore remains very poorly understood. We recently proposed a mathematical model predicting the emergence of a specific non‐Gaussian distribution of polygonal cell shapes from the stochastic cell division process in epithelial cell sheets; this cell shape distribution appears to be conserved across a diverse set of animals and plants.1 The use of such topological models to study the process of cellular morphogenesis has a long history, starting almost a century ago, and many insights from those original works influence current experimental studies. Here we review current and past literature on this topic while exploring some new ideas on the origins and implications of topological order in proliferating epithelia. BioEssays 30:260–266, 2008. © 2008 Wiley Periodicals, Inc.
A new role of the rDNA and nucleolus in the nucleus—rDNA instability maintains genome integrity
Authors: Kobayashi Takehiko 
Published: February 2008

AbstractThe nucleolus is a region of the nucleus with high protein density and it acts as a ribosome factory. The nucleolus contains a distinct region of the genome, the ribosomal RNA gene repeats (rDNA) that supply ribosomal RNA (rRNA) molecules. The rDNA is the most‐abundant gene and occupies a large part of the genome, for example, there are thousands of rDNA copies in the genomes of plant cells. Therefore, it is natural to suppose that the condition of the rDNA, such as its stability, might affect cellular functions. Here I would like to propose a new model regarding the roles of the rDNA and nucleolus. The key point of this model is that they act to preserve genome stability and trigger aging. BioEssays 30:267–272, 2008. © 2008 Wiley Periodicals, Inc.
Losing B cell identity
Authors: Carotta Sebastian , Nutt Stephen L. 
Published: February 2008

AbstractThe transcription factor Pax5 is essential for the initial commitment of hematopoietic progenitors to the B cell lineage. Recently, our understanding of the lineage commitment process has been extended with the finding that Pax5 is also continuously required throughout B cell development to reinforce commitment, as inactivation of Pax5 in mature B cells results in their de‐differentiation to a progenitor stage that is capable of multi‐lineage potential.1 The reliance of B cell identity on a single gene is not without its problems as the loss of Pax5 results in B cell malignancies in mouse models and mutation in human PAX5 is the most‐common genetic lesion in acute lymphoblastic leukemia. BioEssays 30:203–207, 2008. © 2008 Wiley Periodicals, Inc.
Assessment of cell engineering strategies for improved therapeutic protein production in CHO cells
Authors: Mohan Chaya , Kim Yeon‐Gu , Koo Jane , Lee Gyun Min 
Published: February 2008

AbstractRecombinant glycoprotein therapeutics have proven to be invaluable pharmaceuticals for the treatment of various diseases. Chinese hamster ovary (CHO) cells are widely used in industry for the production of these proteins. Several strategies for engineering CHO cells for improved protein production have been tried with considerable results. The focus has mainly been to increase the specific productivity and to extend the culture longevity by preventing programmed cell death. These CHO cell engineering strategies, particularly those developed in Korea, are reviewed here.
The prognostic value of combined intracoronary pressure and blood flow velocity measurements after deferral of percutaneous coronary intervention
Authors: Meuwissen Martijn , Chamuleau Steven A.J. , Siebes Maria , de Winter Robbert J. , Koch Karel T. , Dijksman Lea M. , van den Berg Anja J. , Tijssen Jan G.P. , Spaan Jos A.E. , Piek Jan J. 
Published: February 2008

AbstractObjectives: We evaluated deferral of PCI of intermediate coronary lesions (IL) using fractional (FFR) and coronary flow reserve (CFR) hyperemic stenosis resistance index (HSR) in patients with a negative or nondiagnostic and noninvasive stress tests. Background: Outcome after deferral of PCI of IL with discordant results between FFR and CFR is unknown. Methods: PCI was deferred in 186 IL (mean diameter stenosis: 52%). Patients were divided according to the results of FFR and CFR in group A; FFR ≥ 0.75 and CFR ≥ 2.0 (n = 129), group B; FFR ≥ 0.75 and CFR 2.0 (n = 28), group C; FFR 0.75 and CFR ≥ 2.0 (n = 23) and group D; FFR 0.75 and CFR 2.0 (n = 6). Patients were followed for one year to document major adverse cardiac events (MACE). Results: Nineteen MACEs (0 deaths, 4 myocardial infarctions, 1 CABG, and 14 PCIs) occurred during a follow up of 323 ± 88 days. MACE rate was lowest (4.7%) when FFR, CFR, and HSR were normal. A higher MACE rate was observed when concordant abnormal (group D) or discordant results between FFR and CFR (group B and C) were compared to concordant normal values (group A, 33.3% vs. 19.7% vs. 5.4%, P = 0.008). Multivariate regression analysis showed a higher predictive power for HSR than for FFR and CFR. Conclusions: Abnormal FFR or abnormal CFR was documented in 31% of intermediate coronary lesions. Deferral of PCI in this group was associated with a high MACE rate, which underscores the rationale of combined pressure and flow measurements providing a stenosis resistance index that is better suited for clinical decision making in these lesions. © 2008 Wiley‐Liss, Inc.
Transient left ventricular apical ballooning: A unifying pathophysiologic theory at the edge of Prinzmetal angina
Authors: Angelini Paolo 
Published: February 2008

AbstractIntroduction:Takotsubo or ampulla transient left ventricular apical ballooning (LVAB) cardiomyopathy has been described as a clinical syndrome characterized by the sudden onset of chest pain, cardiac failure, ischemic changes on electrocardiography, and apical severe myocardial dysfunction in the presence of “normal” coronary arteries on angiography. All features last from a few days to a few weeks.Methods and Results:On the basis of previous knowledge and in light of our recent experience with acetylcholine testing in this condition, the cases of four patients are described and preliminary but sound arguments are given to support the theory that LVAB is caused by severe, sustained spasm of many or all of the coronary vessels. In one of these patients, experimental reproduction of LVAB occurred in the catheterization laboratory during acetylcholine testing (as evidenced by echocardiographic monitoring), while in two other patients, the test provoked similar, extensive angiographic vasospasm and suggestive symptoms. In addition, the similarities and differences that exist between LVAB and Prinzmetal angina are discussed.Conclusion:To evaluate the pathogenesis of LVAB, it is proposed that acetylcholine testing be routinely performed under specific, prospective, investigational protocols at specialized centers. © 2008 Wiley‐Liss, Inc.
Prognostic value of troponin after elective percutaneous coronary intervention: A meta‐analysis
Authors: Nienhuis Mark B. , Ottervanger Jan Paul , Bilo Henk J.G. , Dikkeschei Bert D. , Zijlstra Felix 
Published: February 2008

AbstractBackground: Although the prognostic importance of troponin in patients with anacute coronary syndrome is clear, the significance of troponin elevation after elective percutaneous coronary intervention (PCI) is a subject of debate. However, most studies up to now had a small sample size and insufficient events during follow‐up. Methods: Electronic and manual searches were performed of studies reporting on prognosis of troponin after elective PCI. A meta‐analysis was done of all suitable studies, with death in follow‐up as primary endpoint and the combination of death or nonfatal myocardial infarction in follow‐up as secondary endpoint. Results: 20 studies involving 15,581 patients were included. These studies were published between 1998 and 2007. Overall, troponin was elevated after elective PCI in 32.9% of patients. The follow‐up period varied between 3 and 67 months (mean 16.3). Increased mortality was significantly associated with troponin elevation after PCI (4.4% vs. 3.3%, P = 0.001; OR 1.35). Furthermore, the combined endpoint of mortality or nonfatal myocardial infarction also occurred more often in patients with post‐procedural troponin elevation (8.1% vs. 5.2%, P < 0.001; OR 1.59). Conclusions: According to this meta‐analysis, troponin elevation after elective PCI provides important prognostic information. © 2008 Wiley‐Liss, Inc.
Stenting complex aortic arch obstructions
Authors: Holzer Ralf J. , Chisolm Joanne L. , Hill Sharon L. , Cheatham John P. 
Published: February 2008

AbstractObjective:To present our institutional experience of endovascular stent therapy in patients with complex aortic arch lesions.Background:The management of aortic arch obstructions is complex and many physicians are either reluctant to treat mild–moderate aortic arch lesions associated with systemic hypertension or instead refer to high‐risk surgical alternatives. Reported data on transcatheter stent therapy of complex aortic arch lesions are scarce.Methods:Between October 2002 and November 2006, 40patients (pts) had complex aortic arch lesions treated with stent implantation in 42 procedures (proc). Aortic arch hypoplasia was present in 30/42 proc (71.4%). The median age was 10 year (16 days ‐ 37 years). In 40/42 proc (95.2%) patients had previous transcatheter or surgical aortic arch interventions.Results:Procedural success in achieving a peak systolic gradient reduction to ≤10 mm Hg with an improvement in the diameter to ≥90% of the “normal” adjacent aortic arch was achieved in 38/42 proc (90.5%). The diameter of the arch obstruction increased from a median of 7.55 mm to a median of 14 mm (P < 0.0001) and the peak systolic gradient was reduced from a median of 23 mm Hg to a median of 2 mm Hg (P < 0.0001). Arch vessels were crossed in 31/42 proc (73.8%). Periprocedural adverse events were encountered in 13/42 proc (30.9%), predominately in patients with a weight below 10 kg or univentricular physiology. The median follow‐up was 1 year (32 days ‐ 3.8 years). The incidence of systemic hypertension was significantly reduced from 22/42 (52.4%) before the procedure to 6/39 (15.4%) at the most recent follow‐up (P = 0.0005). CT or MRI evaluations were performed in 18 pts, documenting all crossed arch vessels to appear patent.Conclusions:Stenting of complex aortic arch lesions can be performed safely and effectively with excellent, immediate, and midterm results. Patients with a weight below 10 kg or after Hybrid stage I palliation are at increased risk of adverse events. Stents can be placed across major arch vessels without compromising distal perfusion in otherwise normal vasculature. © 2008 Wiley‐Liss, Inc.
Relation of corrected thrombolysis in myocardial infarction frame count and ST‐segment resolution to myocardial tissue perfusion after acute myocardial infarction
Authors: Li Chun‐Mei , Zhang Xing‐Hua , Ma Xiao‐Jing , Zhu Xing‐Lei 
Published: February 2008

AbstractObjectives: To evaluate myocardial tissue perfusion by corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC) and ST‐segment resolution after successful percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). Background: Early and sustained potency of infarct‐related artery (IRA) has become the main goal of reperfusion therapy in patients with AMI. However, myocardial tissue perfusion may remain impaired even after the achievement of TIMI grade 3 flow of the epicardial artery without residual stenosis. Methods: CTFC was measured after successful PCI in 63 patients with first AMI. The extent of ST‐segment resolution was recorded 1 hr after reperfusion therapy. The wall motion score index (WMSI) was assessed before and 1 month after PCI. Then we studied the correlation between CTFC, ST‐segment resolution, and WMSI. Results: According to CTFC, the patients with TIMI grade 3 flow after PCI were divided into two groups: CTFC fast group and CTFC slow group. CTFC fast group had higher percentage of complete ST resolution (54.1% vs. 25.0%, P < 0.05) and lower percentage of no ST resolution (2.6% vs. 29.2%, P < 0.05). Improvement of WMSI in the CTFC fast group was significantly greater than that of the CTFC slow group (1.30 ± 0.41 vs. 0.64 ± 0.30, P < 0.05). CTFC had a significant negative correlation with the change in WMSI (r = −0.75, P < 0.01). Conclusions: Combined with ST‐segment resolution, CTFC could predict risk for patients with successful reperfusion therapy after AMI and provide evidence for additional adjunctive treatment. © 2008 Wiley‐Liss, Inc.
A new ostial stent positioning system (Ostial Pro™) for the accurate placement of stents to treat aorto‐ostial lesions
Authors: Fischell Tim A. , Malhotra Surender , Khan Shakeel 
Published: February 2008

AbstractBackground:The stenting of aorto‐ostial lesions in the native coronary circulation, renal arteries, and saphenous vein grafts is technically challenging.Methods:We report the first in the world use of the Ostial Pro™, a novel nitinol‐based device, utilized in conjunction with standard stenting techniques to assist in the precise placement of stents for the treatment of aorto‐ostial lesions.Results:The Ostial Pro, is a relatively simple nitinol device that is positioned within the guiding catheter. It has distal, self‐expanding legs that are advanced just distal to the tip of the guiding catheter after the ostial lesion has been crossed with the coronary guidewire and stent delivery system. The expanded nitinol legs prevent the entry of the guiding catheter into the target vessel, mark the plane of the aortic wall, and align the tip of the guide with the aorto‐ostial plane. We report the successful and precise placement of stents in the aorto‐ostial location in two patients with; (1) a saphenous vein graft ostial lesion and (2) a right coronary ostial lesion, using the new Ostial Pro stent positioning device. Excellent stent positioning, relative to the aorto‐ostial plane, was confirmed by angiography and long axis intravascular ultrasound in both cases.Conslusions:(1) The Ostial Pro is a new, commercially available (FDA cleared), nitinol device that is simple to use and appears effective in allowing the precise placement of stent(s) at the aorto‐ostial location. (2) This approach may provide a simple and effective means to assure accurate stent placement in these difficult to treat lesions. © 2008 Wiley‐Liss, Inc.