bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of poly(sodium acrylate‐co‐sodium 1‐(acryloyloxy) propan‐2‐yl phosphate) and comparative study on its swelling properties with poly(sodium acrylate) and poly(sodium acrylate‐co‐2‐hydroxypropyl acrylate)
Authors: Chen Zhenbin , Liu Mingzhu , Qi Xiaohua , Liu Zhen 
Published: March 2007

AbstractA new superabsorbent copolymer, poly(sodium acrylate‐co‐sodium 1‐(acryloyloxy) propan‐2‐yl phosphate) [P(SA‐co‐SAPP)], was synthesized by a novel prepared monomer, 1‐(acryloyloxy) propan‐2‐yl phosphoryl dichloride. The swelling properties of the superabsorbent were investigated by comparison with poly(sodium acrylate) (PSA) and the copolymer of poly(sodium acrylate‐co‐2‐hydroxypropyl acrylate) [P(SA‐co‐HPA)]. The results showed that (1) the superabsorbent containing sodium 1‐(acryloyloxy) propan‐2‐yl phosphate had higher water absorbency at general testing conditions; (2) the swelling properties of P(SA‐co‐SAPP) and PSA were obviously influenced by pH of solutions, which were different from that of P(SA‐co‐HPA); (3) the swelling process and the saturated water absorbency of all superabsorbents were remarkably affected by cations, especially multivalent ones, while barely affected by anions. POLYM. ENG. SCI., 47:728–737, 2007. © 2007 Society of Plastics Engineers.
Poly(triarylamine): Its synthesis, properties, and blend with polyfluorene for white‐light electroluminescence
Authors: Lin Hung‐Yi , Liou Guey‐Sheng , Lee Wen‐Ya , Chen Wen‐Chang 
Published: March 2007

AbstractA new high‐molecular‐weight poly(triarylamine), poly[di(1‐naphthyl)‐4‐anisylamine] (PDNAA), was successfully synthesized by oxidative coupling polymerization from di(1‐naphthyl)‐4‐anisylamine (DNAA) with FeCl3 as an oxidant. PDNAA was readily soluble in common organic solvents and could be processed into freestanding films with high thermal decomposition and softening temperatures. Cyclic voltammograms of DNAA and PDNAA exhibited reversible oxidative redox couples at the potentials of 0.85 and 0.85 V, respectively, because of the oxidation of the main‐chain triarylamine unit. This suggested that PDNAA is a hole‐transporting material with an estimated HOMO level of 5.19 eV. The absorption maximum of a PDNAA film appeared at 370 nm, with an estimated band gap of 2.86 eV from the absorption edge. Unusual multiple photoluminescence maxima were observed at 546 nm, and this suggested its potential application in white‐light‐emission devices. Nearly white‐light‐emission devices could be obtained with either a bilayer‐structure approach {indium tin oxide/poly(ethylenedioxythiophene):poly(styrene sulfonate)/PDNAA/poly[2,7‐(9,9‐dihexylfluorene)] (PF)/Ca} or a polymer‐blend approach (PF/PDNAA = 95:5). The luminance yield and maximum external quantum efficiency of the light‐emitting diode with the PF/PDNAA blend as the emissive layer were 1.29 cd/A and 0.71%, respectively, and were significantly higher than those of the homopolymer. This study suggests that the PDNAA is a versatile material for electronic and optoelectronic applications. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1727–1736, 2007
Strain hardening of high density polyethylene
Authors: Haward R. N. 
Published: March 2007

AbstractThe introduction of true stress strain measurements, at constant strain rate, has promoted the development of empirical or semiempirical models for large deformations in thermoplastics. One such theory, which proposes that the post yield deformation process can be represented by equations derived from the theories of rubber elasticity, has been successfully applied to several glassy polymers. Unexpectedly, it can also model the post yield deformation of many different grades of polyethylene, even when rubber theory is employed in the simplest Gaussian form. Strain hardening is then represented by the single strain hardening coefficient Gp. Examples are given of this equation, which can be modified to give the true engineering or nominal stress σn and then be differentiated to give dσn/dλ = Gp − Y0 / λ2 + 2Gp / λ3, where Y0 is the yield stress and λ the extension ratio. Negative values of this differential then predict the onset of necking in tension and positive values stabilization of the neck. The relation of Gp to molecular weight is then discussed using literature measurements for polyethylenes of differing molecular weight and similar molecular weight distributions. When these results are then plotted, a strong dependency of Gp on molecular weight is observed. Some implications of these measurements are then considered. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1090–1099, 2007
Effects of clay nanoparticles and electron irradiation in the crystallization rate of syndiotactic polypropylene
Authors: Cerrada M. L. , Rodríguez‐Amor V. , Pérez E. 
Published: March 2007

AbstractSeveral composites of a metallocene syndiotactic polypropylene with an organophilic silicate have been prepared and analyzed to investigate the effects of the nanoparticles on the crystallization of syndiotactic polypropylene. Moreover, the influence of an electron‐irradiation dose of 166 kGy on the different materials has been studied. Although the melting temperatures are practically unchanged, irradiation leads to a considerably slower crystallization rate of the syndiotactic polypropylene homopolymer in such a way that an important cold crystallization has been observed in the second melting along with a much higher value of the isothermal crystallization half‐time. On the contrary, the nanocomposites are much less sensitive to irradiation because only a small shift of the crystallization temperature has been observed, and the isothermal crystallization half‐time remains practically unaffected. However, irradiation leads to important changes in the low‐angle region of X‐ray diffractograms. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1068–1076, 2007
Property‐based sequence representations do not adequately encode local protein folding information
Authors: Solis A.D. , Rackovsky S. 
Published: March 2007

AbstractWe examine the informatic characteristics of amino acid representations based on physical properties. We demonstrate that sequences rewritten using contracted alphabets based on physical properties do not encode local folding information well. The best four‐character alphabet can only encode ∼57% of the maximum possible amount of structural information. This result suggests that property‐based representations that operate on a local length scale are not likely to be useful in homology searches and fold‐recognition exercises. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Filariasis vector in China: insecticide resistance and population structure of mosquito Culex pipiens complex
Authors: Cui Feng , Tan Yi , Qiao Chuan‐Ling 
Published: March 2007

AbstractSeven field populations of mosquito Culex pipiens complex (Diptera: Culicidae) were collected from four provinces of China. The resistance status of larvae to dichlorvos, parathion, chlorpyrifos, fenobucarb (BPMC) and propoxur were determined by bioassays, disclosing that they were more resistant to organophosphate (moderate or low resistance) than to carbamate (low or no significant resistance) insecticides. Starch gel electrophoresis confirmed the presence and distribution of overproduced esterases B1, A2‐B2, A8‐B8 and A9‐B9, the frequencies of which varied according to their regional origins. Electrophoretic polymorphism at four putatively neutral loci (got‐1, got‐2, pgi and pgm) showed that the overall genetic differentiation found across all populations was significantly large (Fst = 0.28, P < 10−4), and genetic exchange was slightly restricted by distance isolation (P = 0.018). Copyright © 2007 Society of Chemical Industry
Learning and prediction of slip from visual information
Authors: Angelova Anelia , Matthies Larry , Helmick Daniel , Perona Pietro 
Published: March 2007

AbstractThis paper presents an approach for slip prediction from a distance for wheeled ground robots using visual information as input. Large amounts of slippage which can occur on certain surfaces, such as sandy slopes, will negatively affect rover mobility. Therefore, obtaining information about slip before entering such terrain can be very useful for better planning and avoiding these areas. To address this problem, terrain appearance and geometry information about map cells are correlated to the slip measured by the rover while traversing each cell. This relationship is learned from previous experience, so slip can be predicted remotely from visual information only. The proposed method consists of terrain type recognition and nonlinear regression modeling. The method has been implemented and tested offline on several off‐road terrains including: soil, sand, gravel, and woodchips. The final slip prediction error is about 20%. The system is intended for improved navigation on steep slopes and rough terrain for Mars rovers. © 2006 Wiley Periodicals, Inc.
Collaboration as a pathway for sustainability
Authors: Lozano Rodrigo 
Published: March 2007

AbstractConventional individualistic behaviours with their quest for profit maximization and wealth accumulation have created economic, environmental and social imbalances in today's world. These imbalances threaten to become worse in the coming years, decades and centuries. Calls and efforts towards sustainable development (SD) seek to establish a dynamic equilibrium among these elements. One of the key elements in the transition towards more sustainable societies is collaboration.This research presents three game theory tools to help rationalize that collaborative behaviours offer better results than individualistic ones. The first presented is the prisoners' dilemma. The second is the tragedy of the commons, a tool similar to the prisoners' dilemma but with more actors increasing the complexity. The third, the Nash equilibrium, offers a mathematical way to attempt to reach a system's optimum, i.e. to obtain the result that would in a totality benefit all the players. The tools are linked to SD problems. Copyright © 2007 John Wiley & Sons, Ltd and ERP Environment.
Some issues in software reliability assessment
Authors: Veevers Alan 
Published: March 2007

AbstractThe debate between those who prefer formal methods and those who advocate the use of reliability‐growth models in the assessment of software reliability continues. Some issues arising from this conflict are raised and discussed, beginning with the definition of quantified software reliability. After arguing that the stochastic modelling approach is conceptually sound, its possible relationship with the structure of the software is discussed. Evidence that certain structural counts can be used in place of time as the argument in reliability growth models is reported. The question of the extent to which the many non‐stochastic metrics now available contribute to software reliability quantification is aired. A relationship between reliability and a hierarchy of coverage metrics is reported, which may help to draw together the modellers and the testers.
Application of a [13CO2] breath test to study short-term amino acid catabolism during the postprandial phase of a meal
Authors: Bujko Jacek , Schreurs Victor V. A. M. , Nolles Jelmer A. , Verreijen Amely M. , Koopmanschap Rudie E. , Verstegen Martin W. A. 
Published: March 2007

A [13CO2] breath test was applied as a non-invasive method to study the catabolism of ingested amino acids shortly after a meal. This test requires the ingestion of a [1-13C]-labelled amino acid and the analysis of expired air for [13C] enrichment and CO2. The recovery of label as [13CO2] reflects the catabolism of the [1-13C]-labelled substrate. Such a non-steady state approach provides information that is complementary to the information obtained by steady-state methods using a primed continuous infusion of tracer amino acids during the fed state. In a model study with twenty adult male rats, two groups of animals were fed twice a day with one of two semi-synthetic iso-energetic diets. One diet contained egg white protein (EW) as the sole amino acid source. The second diet contained a mixture of free amino acids with a pattern similar to that of the EW diet. On day 5 of the dietary treatment, l-[1-13C]leucine, either bound in EW protein or in free form, was ingested as part of the morning meal. The expired air was sampled at 30 min intervals for 5 h. The rate of recovery ranged from 0 % to 6 % of the dose/h. Up to 120 min after the onset of the meal, the recovery values for the free amino acid diet were higher than those for the EW diet. Differences in recovery reflect differences in postprandial utilisation. The differences in label recovery were mainly determined by the [13C] enrichment of the expired air. As a consequence, CO2 measurements are not mandatory when CO2 production is comparable.
Some bovine proteins behave as dietary fibres and reduce serum lipids in rats
Authors: Ruvini Liyanage , Hashimoto Naoto , Han Kyu-Ho , Kajiura Teppei , Watanabe Shoko , Shimada Ken-ichiro , Sekikawa Mitsuo , Ohba Kiyoshi , Fukushima Michihiro 
Published: March 2007

We examined the physiological importance of bovine dietary proteins in rats fed diets prepared from bovine Achilles' tendons and arteries. Rats were fed for 4 weeks, with a 20 % casein diet (CON), in comparison with two diets containing 15 % casein and 5 % of either bovine Achilles' tendon (AC) or artery (AR) protein preparations. The serum total cholesterol concentration and non-HDL-cholesterol level in the AR-fed group were significantly lower (P < 0·05) than those in the CON-fed group at the end of the 4-week feeding period. The hepatic mRNA were measured, and the hydroxyl methyl glutaryl-CoA reductase mRNA level was significantly lower (P < 0·05) in the AR-fed group compared with the CON-fed group. Total hepatic cholesterol concentration in AC-fed rats was significantly (P < 0·05) higher than in the CON-fed group. The serum TAG concentration and fatty acid synthase mRNA level in AC- and AR-fed groups were significantly lower (P < 0·05) compared with the CON-fed group throughout the feeding period. Faecal neutral sterol excretion was significantly (P < 0·05) higher in the AC- and AR-fed groups compared with the CON-fed group. The results of the present study demonstrate that some bovine dietary proteins have similar functions as dietary fibres, lowering serum lipid concentration by enhancing faecal neutral sterol excretion or suppressing lipid synthesis in the liver. Moreover, favourable amino acid compositions in the AR and AC preparations may also have a lowering effect on plasma lipid concentration in bovine protein diet-fed groups.
The effect of absence of protozoa on rumen biohydrogenation and the fatty acid composition of lamb muscle
Authors: Yáñez-Ruiz David R. , Williams Selwyn , J. Newbold Charles 
Published: March 2007

The effects of the absence of protozoa in the rumen of lambs on animal growth, rumen fermentation, microbial diversity and fatty acid profiles in abomasal fluid and intramuscular fat were measured in ten control and ten protozoa-free (PF) lambs. PF lambs were prepared by isolating them from ewes within the first 24 h after birth. The PF and control lambs were kept for 4 months in two different fields and received a daily supplement of 250 g concentrate. The bacterial populations visualised by denaturing gradient gel electrophoresis differed between the two groups of animals and showed a higher bacterial diversity in control lambs than in PF lambs. Abomasal contents from control lambs contained higher concentrations of 22 : 5n-3 and 22 : 6n-3 and lower concentrations of vaccenic acid (trans-11–18 : 1) and 20 : 3n-6 than PF lambs. The rest of the fatty acids, including the conjugated linoleic acid (CLA) isomers, were present at the same concentrations in abomasal contents from both experimental groups. Fatty acid composition in intramuscular fat showed differences between the groups. PF lambs had higher proportions of 18 : 0, 18 : 3,trans-10,cis-12-CLA and total SFA than control lambs. Control lambs had higher proportions ofcis-9–18 : 1,cis-9,cis-12–18 : 2, 20 : 3n-6, 22 : 6n-3 (DHA) and MUFA. In conclusion, rumen defaunation led to higher tissue levels of thetrans-10,cis-12-CLA isomer and SFA and lower PUFA:SFA ratio andn-3 PUFA in lamb muscle.
Nanoscopic Materials
Authors: Roduner Emil 
Published: March 2007

Nanotechnology has been hailed as a key technology of the 21st century. The scope of this field is huge and could have a wide influence on many aspects of life. Nanoscience; the manipulation of matter at the atomic and molecular level, and nanomaterials; materials so small that their behaviour and characteristics deviate from those of macroscopic specimens and may be predicted by scaling laws or by quantum confinement effects, are discussed in Nanoscopic Materials: Size - Dependent Phenomena.
The book focuses on a qualitative and quantitative approach discussing all areas of nanotechnology with particular emphasis on the underlying physico-chemical and physical principles of nanoscience. Topics include electronic structure, magnetic properties, thermodynamics of size dependence and catalysis. There is also a section discussing the future potential of the field and the ethical implications of nanotechnology.
The book is ideal for graduate students of chemistry and materials science and researchers new to the field of nanoscience and nanotechnology.
Temperature-, concentration- and cholesterol-dependent translocation of L- and D-octa-arginine across the plasma and nuclear membrane of CD34+ leukaemia cells
Authors: Fretz Marjan M. , Penning Neal A. , Al-Taei Saly , Futaki Shiroh , Takeuchi Toshihide , Nakase Ikuhiko , Storm Gert , Jones Arwyn T. 
Published: March 2007

Delineating the mechanisms by which cell-penetrating peptides, such as HIV-Tat peptide, oligoarginines and penetratin, gain access to cells has recently received intense scrutiny. Heightened interest in these entities stems from their ability to enhance cellular delivery of associated macromolecules, such as genes and proteins, suggesting that they may have widespread applications as drug-delivery vectors. Proposed uptake mechanisms include energy-independent plasma membrane translocation and energy-dependent vesicular uptake and internalization through endocytic pathways. In the present study, we investigated the effects of temperature, peptide concentration and plasma membrane cholesterol levels on the uptake of a model cell-penetrating peptide, L-octa-arginine (L-R8) and its D-enantiomer (D-R8) in CD34+ leukaemia cells. We found that, at 4–12 °C, L-R8 uniformly labels the cytoplasm and nucleus, but in cells incubated with D-R8 there is additional labelling of the nucleolus which is still prominent at 30 °C incubations. At temperatures between 12 and 30 °C, the peptides are also localized to endocytic vesicles which consequently appear as the only labelled structures in cells incubated at 37 °C. Small increases in the extracellular peptide concentration in 37 °C incubations result in a dramatic increase in the fraction of the peptide that is localized to the cytosol and promoted the binding of D-R8 to the nucleolus. Enhanced labelling of the cytosol, nucleus and nucleolus was also achieved by extraction of plasma membrane cholesterol with methyl-β-cyclodextrin. The data argue for two, temperature-dependent, uptake mechanism for these peptides and for the existence of a threshold concentration for endocytic uptake that when exceeded promotes direct translocation across the plasma membrane.
Erythropoietin/erythropoietin‐receptor system is involved in angiogenesis in human hepatocellular carcinoma
Authors: Ribatti D , Marzullo A , Gentile A , Longo V , Nico B , Vacca A , Dammacco F 
Published: March 2007

Aims:  To correlate microvascular density and erythropoietin (Epo)/Epo‐receptor (EpoR) expression in endothelial and tumour cells with histopathological type in hepatocellular carcinoma (HCC).Methods and results:  Specimens of primary HCC obtained from 50 patients who had undergone curative hepatectomy were investigated immunohistochemically by using anti‐CD31, anti‐Epo and anti‐EpoR antibodies. Poorly differentiated HCC had a higher degree of vascularization than other stages and Epo/EpoR expression in both tumour and endothelial cells increased in parallel with grade of malignancy and was highly correlated with the extent of angiogenesis.Conclusions:  Epo/EpoR levels correlate with angiogenesis and progression of patients with HCC and these findings suggest the presence of a loop in the Epo/EpoR system, i.e. Epo is secreted by hepatic tumour cells and it affects vascular endothelial cells via its receptors and promotes angiogenesis in a paracrine manner. It is thus suggested that Epo is an important factor in hepatic tumour angiogenesis. Understanding the mechanisms of HCC angiogenesis provides a basis for a rational approach to the development of antiangiogenic therapy in patients with hepatic cancer.
Multinucleated stromal giant cells in colonic lamina propria
Authors: Wu M L , Zhao X 
Published: March 2007

Aims:  Multinucleated stromal giant cells occur in the anus, genitals and many other organs. They resemble myofibroblasts, react to local injury and are found incidentally or in association with various lesions. They have only rarely been reported to occur in the colon. The aim was to firmly establish their existence in colorectal lamina propria.Methods and results:  Specimens from one hundred biopsies taken from throughout the colon (70%) and rectum (30%) were retrospectively reviewed. Multinucleated stromal giant cells occurred in 23 specimens (23%), were pancolonic but surprisingly spared rectal mucosa (0%). Multinucleated stromal giant cells occurred in both normal mucosa and abnormal mucosa and appeared to be larger and more numerous in abnormal mucosa than in normal mucosa. Specimens with tubular adenomas appeared to have strikingly abundant multinucleated stromal giant cells with large numbers of nuclei. Immunohistochemistry and ultrastructural examination showed features consistent with myofibroblastic differentiation.Conclusions:  We have firmly established the existence of multinucleated stromal giant cells in colonic lamina propria and confirm their myofibroblastic differentiation. They may be more common in abnormal mucosa and particularly prominent in the setting of tubular adenoma. Absence of rectal multinucleated stromal giant cells may represent a microanatomical difference between the colon and rectum.
Prognostic and biological significance of cytokeratin 19 in pancreatic endocrine tumours
Authors: La Rosa S , Rigoli E , Uccella S , Novario R , Capella C 
Published: March 2007

Aim:  The prognosis of well‐differentiated pancreatic endocrine tumours (PETs) is difficult to establish on a histological basis. The expression of cytokeratin (CK19) has recently been proposed as an indicator of unfavourable outcome. However, this finding still needs to be verified and to be compared with more frequently used prognosticators such as proliferative indices, vascular and/or perineural invasion. The aim of this study was to evaluate the prognostic value of CK19 expression in PETs.Methods and results:  One hundred and forty‐five PETs were studied using two different anti‐CK19 monoclonal antibodies (BA17 and RCK108). The results were statistically compared with proliferation markers, vascular and perineural invasion and the presence of metastases. On univariate analysis, CK19 immunoreactivity correlated with prognosis only when it was detected with the RCK108 antibody and only in the whole group of PETs and in insulinomas. Conversely, it did not predict survival in non‐functioning neoplasms. Ki67 index, mitotic count, vascular and perineural invasion were all statistically correlated with prognosis. On multivariate analysis, only the Ki67 index and metastases were independent prognosticators.Conclusions:  CK19 expression correlates with patient survival only when detected with the RCK108 antibody and mainly in insulinomas. Ki67 index and metastases represent the only two independent predictors of survival.