bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of end‐functionalized AB copolymers. II. Synthesis and characterization of carboxyl‐terminated poly(ethylene glycol)–poly(amino acid) block copolymers
Authors: Zhang Sheng , Qing Jie , Xiong Chengdong , Peng Yuxing 
Published: June 2004

AbstractAB block copolymers composed of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(amino acid) with a carboxyl group at the end of PEG were synthesized with α‐carboxylic sodium‐ω‐amino‐PEG as a macroinitiator for the ring‐opening polymerization of N‐carboxy anhydride. Characterizations by 1H NMR, IR, and gel permeation chromatography were carried out to confirm that the diblock copolymers were formed. In aqueous media this copolymer formed self‐associated polymer micelles that have a carboxyl group on the surface. The carboxyl groups located at the outer shell of the polymeric micelle were expected to combine with ligands to target specific cell populations. The diameter of the polymer micelles was in the range of 30–80 nm. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3527–3536, 2004
Aliphatic–aromatic copolyesters derived from 2,2,4,4‐tetramethyl‐1,3‐cyclobutanediol
Authors: Hoppens Nathan C. , Hudnall Todd W. , Foster Adam , Booth Chad J. 
Published: June 2004

AbstractWith the massive changes taking place in the world today, the development of new thermally and mechanically stable polymeric materials is of utmost importance. This article focuses on the synthesis and thermal characterization of a new series of copolyesters that incorporate both aromatic as well as aliphatic diols. This is of interest because most polymer materials that exhibit high thermal and/or mechanical properties contain aromatic monomer units only. These aromatic units usually contribute to either the thermal or mechanical properties but typically not both. An example of this is bisphenol A polycarbonate, which has high mechanical properties but only moderate thermal properties when compared, for example, to polyimides. In recent years there has been an interest in copolyesters that contain 2,2,4,4‐tetramethyl‐1,3‐cyclobutanediol (CBDO). This aliphatic monomer imparts some very unique thermal as well as mechanical properties. This article will report the thermal properties of a new series of CBDO‐based copolyesters. These polymers include CBDO, a series of bisphenols, and terephthaloyl chloride. The series of bisphenols discussed here include bisphenol A, AF, F, and HPF. These polymers display glass transition temperatures near 200 °C and decomposition temperatures from 390–420 °C (Argon) and from 385–410 °C (Air). © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3473–3478, 2004
Synthesis of di‐ and tetra‐adducts by addition of polystyrene macroradicals onto fullerene C60
Authors: Audouin Fabrice , Nuffer Richard , Mathis Claude 
Published: June 2004

AbstractBr‐terminated polystyrenes of controlled molar masses and low polydispersities prepared by atom transfer radical polymerization (ATRP) can be converted to macroradicals using an appropriate catalytic complex (CuBr/bipyridine/100 °C). The addition of this macroradicals PS° to 6–6 bonds of C60 follows a specific atom transfer radical addition mechanism that favors the grafting of even number of chains onto the fullerene core. This peculiar mechanism, resulting from the properties of C60, offers an easy synthetic route toward well‐defined di‐ and tetra‐adducts. In these adducts the disturbance of the electronic structure of the fullerene is kept at its minimum, as only one double bond needs to be opened on the C60 to add two PS chains and only two double bonds are converted to single bonds in the tetra‐adduct. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3456–3463, 2004
Ab‐initio study of the structural phase transition of SrSe and SrTe under pressure
Authors: Cortona Pietro 
Published: June 2004

AbstractThe cohesive properties and the behavior under pressure of SrSe and SrTe have been investigated by an ab initio method that allows the direct determination of the electron density and the total energy of a system in the framework of the density‐functional theory. A good agreement with the experiment has been found for all the properties considered: lattice parameters, bulk moduli, equations of state, transition pressure from the B1 to the B2 phase, and related quantities. The results are of special interest for the high‐pressure phase: as the experimental values of B and of dB/dp are affected by large uncertainties, the calculated values are probably a better evaluation of them. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Ab initio simulation of the short‐range order structure of Al ions and substitutional Fe, Cr impurities in S.S. Spinel (MgAl2O4)
Authors: Votyakov S. L. , Porotnikov A. V. , Shchapova Yu. V. , Yuryeva E. I. , Ivanovskii A. L. 
Published: June 2004

AbstractThe structure of the short‐range surrounding of aluminum, ferric iron and chromium octahedrally coordinated cations in s.s. spinel MgAl2O4:(Fe,Cr) has been established in the framework of the cluster model. The total energy minimum of [VIMecentIVMg6VIAl6O38]43‐ clusters (Mecent = Al, Fe, Cr) is realized when oxygens of the first coordination sphere of the central cation VIMe are displaced considerably relative to the initial ideal structure. The displacement depends on the central cation of the cluster. The estimated short‐range order parameters including the oxygen parameter u of the spinel are in satisfactory agreement with experimental data. Comparable analysis of the electronic structure of Al, Fe, Cr cations in octahedral positions of the spinel in ideal and relaxed clusters showed that octahedral distortions should be taken into account when interpreting spectroscopic parameters of the natural spinels and evaluating the charge balance in their structure. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Wigner intracule for the Kellner helium‐like ions
Authors: Gill Peter M. W. , Besley Nicholas A. , O'Neill Darragh P. 
Published: June 2004

AbstractThe Kellner wavefunction for a helium‐like ion is the Hartree–Fock solution wherein the orbital is a Slater‐type function with the variationally optimal exponent ζ = Z − 5/16. The Wigner intracule W(u, v) of a system gives the joint quasiprobability of finding two electrons whose position space and momentum space separations are |r1 − r2| = u and |p1 − p2| = v, respectively. In this article, we extend Wigner intracule theory beyond Gaussian‐type functions by deriving W(u, v) for the Kellner helium‐like ions. Although we have not been able to express W(u, v) in closed form, our formulation reduces it to a two‐dimensional integral that can be treated by quadrature. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Comments and references relating to early work in field electron emission
Authors: Kleint Christian 
Published: June 2004

AbstractThis paper adds to the contents of an earlier review entitled ‘On the early history of field emission including attempts of tunnelling spectroscopy’ (Prog. Surf. Sci. 1993; 42: 101) and covers the period up to 1958. In particular, it notes the work on (what one can now recognize as) field‐emission‐induced discharge phenomena in the period 1878–1905 and the work on the developing applications of field emission microscopy in the period 1952–1958, in what had become Drechsler's group in Berlin. Copyright © 2004 John Wiley & Sons, Ltd.
Fabrication of a sub‐wavelength size aperture from a nanosize Si tip using field emission techniques
Authors: Choi Seong S. , Jung M. Y. , Kim D. W. , Park M. J. 
Published: June 2004

AbstractExplorations are reported that aim towards fabricating sub‐wavelength size metal apertures for near‐field optical probes by using Si microfabrication techniques. Nanosize Si tips on an Si(100) wafer were fabricated using conventional microfabrication techniques and then were coated with films of photoresist, gold or chromium. The objective is selective removal of the coating near the tip apex, using field‐assisted techniques, and the aim of this work has been to explore the behaviour of the coated tip when a voltage is applied. With negative bias on a photoresist‐coated tip, arcing leads to selective removal of the photoresist layer. A positively biased Au‐coated Si tip exhibited tip thickening due to field‐induced migration but no clear evidence of Au overlayer removal by field evaporation. With a Cr‐coated tip, an aperture of diameter ∼160 nm diameter has been fabricated using an Ne ion sputter‐etching technique. Copyright © 2004 John Wiley & Sons, Ltd.
Field emission current technique for investigating the energy gap in BCS‐like superconductors
Authors: Uimanov I. V. 
Published: June 2004

AbstractThis paper considers the ‘current techniques’ for field emission investigations of the parameters of BCS‐like superconductors, which are based on observing the change in field emission current upon the superconducting‐to‐normal (or reverse) phase transition. Based on the results obtained, it has been shown that the field emission current density in the superconducting state is greater than that in the normal state everywhere over the temperature range. Comparison of the expressions obtained with available experimental results has shown that they are in good qualitative and quantitative agreement. Calculating the width of the superconducting gap with the use of the experimental data and the expressions derived in presented paper, we have obtained a value very closely approaching the tabulated one. Copyright © 2004 John Wiley & Sons, Ltd.
Characteristics of carbon‐fibre cold field emission tips with a dielectric coating
Authors: Mousa M. S. , Kelly T. F. 
Published: June 2004

AbstractField electron emitters have been prepared by coating a carbon fibre with an epoxylite resin, and their properties investigated. The emission stability is improved compared with an uncoated fibre. An optimum coating thickness of 0.2–0.3 µm has been found. Energy spectra have been measured and peak shifts of up to 1 eV as a function of emission current have been observed. Surprisingly, these peaks shifts are comparable with those found for uncoated carbon fibres and for resin‐coated tungsten emitters. Their origin is not clear, but it seems that resistive drop cannot be the whole explanation. We speculate that these peak shifts may be related to the dynamics of surface‐state occupation at the material/vacuum interface. Copyright © 2004 John Wiley & Sons, Ltd.
Large‐signal and small‐signal electronic equivalent circuits for a field electron emitter
Authors: Hagmann M. J. , Mousa M. S. , Brugat M. , Sheshin E. P. , Baturin A. S. 
Published: June 2004

AbstractLarge‐signal and small‐signal electronic equivalent circuits are developed to describe signal generation by a field electron emitter, with and without a ballast resistor. It is shown that different small‐signal equivalent circuits are needed for the cases where a small alternating voltage variation is applied and where the tunneling process is directly modulated, e.g. by directing a laser at the field emitter. The role of circuit resistances and of the parasitic capacitance between the emitter and its surroundings is crucially different in the two cases, with low‐pass filter behaviour exhibited in the first case and high‐pass filter behaviour in the second. Some consequences for the technical use of a field electron emitter as a non‐linear device are discussed, particularly in applications that involve laser‐assisted field electron emission and in the context of testing field emission tubes. Copyright © 2004 John Wiley & Sons, Ltd.
JCrasher: an automatic robustness tester for Java
Authors: Csallner Christoph , Smaragdakis Yannis 
Published: June 2004

AbstractJCrasher is an automatic robustness testing tool for Java code. JCrasher examines the type information of a set of Java classes and constructs code fragments that will create instances of different types to test the behavior of public methods under random data. JCrasher attempts to detect bugs by causing the program under test to ‘crash’, that is, to throw an undeclared runtime exception. Although in general the random testing approach has many limitations, it also has the advantage of being completely automatic: o supervision is required except for off‐line inspection of the test ases that have caused a crash. Compared to other similar commercial and research tools, JCrasher offers several novelties: it transitively analyzes methods, determines the size of each tested method's parameter‐space and selects parameter combinations and therefore test cases at random, taking into account the time allocated for testing; it defines heuristics for determining whether a Java exception should be considered as a program bug or whether the JCrasher supplied inputs have violated the code's preconditions; it includes support for efficiently undoing all the state changes introduced by previous tests; it produces test files for JUnit, a popular Java testing tool; and it can be integrated in the Eclipse IDE. Copyright © 2004 John Wiley & Sons, Ltd.
A specification language and service‐oriented architecture to support distributed data management
Authors: Blake M. Brian 
Published: June 2004

AbstractIn some research analysis organizations, effort is duplicated when disseminating raw information to multiple research groups. Although the various groups work on different problems, many times, the initial raw information used is the same. A solution to this problem is creating a centralized process for storing and disseminating common information using database technologies. In this paper, the requirements that must be met to create this distributed database management architecture are described. To support these requirements, a specification language, Specialized Format Markup Language (SFML), and supporting service‐oriented architecture, Specialized Format Generation (SFG), are introduced. These implementations and technologies support the translation of data from relational database formats into user‐specified legacy formats. In addition, this implementation supports the presentation of the resulting data across a Web‐based, distributed medium. SFML and SFG incorporate current technologies such as the eXtensible Markup Language (XML), Java Servlets, the eXtensible Stylesheet Language (XSL), and other relational database approaches. Copyright © 2004 John Wiley & Sons, Ltd.
Blood platelets of the cheetah (Acinonyx jubatus)
Authors: du Plessis L. , Botha A.J. , Reyers F. , Stevens K. 
Published: June 2004

AbstractThe blood platelet count and platelet morphology of 22 adult cheetahs was investigated. The platelet counts of the animals displayed a normal distribution, with a mean count of 344×109/l and a mean platelet volume of 11 fl. Morphological and ultrastructural features of the cheetah platelets revealed the typical platelet morphology of anuclear cells, with granules scattered throughout the cytoplasm. The characteristic surface canalicular system and microtubules were present. True cross‐sections of the platelets had a mean area of 2.146 µm2, circumference of 6.805 µm, and mean minimum and maximum projections of 1.000 µm and 2.933 µm, respectively. Zoo Biol 23:263–271, 2004. © 2004 Wiley‐Liss, Inc.
Positive Status of α‐Fetoprotein and des‐γ‐Carboxy Prothrombin: Important Prognostic Factor for Recurrent Hepatocellular Carcinoma
Authors: Kaibori Masaki , Matsui Yoichi , Yanagida Hidesuke , Yokoigawa Norio , Kwon A‐Hon , Kamiyama Yasuo 
Published: June 2004

AbstractThe aim of this study was to evaluate prognostic factors after the recurrence of hepatocellular carcinoma (HCC) in patients who had undergone hepatic resection. We used univariate and multivariate retrospective analyses of 29 clinicopathologic factors in 143 patients with recurrent HCC. Patients were classified into four groups according to the positivity of tumor markers at the time of recurrence. Survival rates and prognostic factors were then compared among the four groups. Multivariate analysis revealed four independent prognostic factors at recurrence: albumin level < 3.5 g/dl (p = 0.0003), period until recurrence ≤ 1 year (p = 0.0004), positive status of α‐fetoprotein and des‐γ‐carboxy prothrombin (AFP+/DCP+) (p < 0.0001), and portal vein invasion (p < 0.0001). Among groups with varying status of AFP/DCP, the survival rate in patients with AFP+/DCP+ at recurrence was significantly lower than those in the other three groups (+/+ 15.9% vs. +/‐ 47.2%, ‐/+ 44.8%, or ‐/‐ 61.1% at 3 years: p < 0.05). The AFP+/DCP+ group also had significantly higher rates of the recurrence appearing ≤ 1 year after operation (+/+ 68.3% vs. +/‐ 45.2%, ‐/+ 41.9%, or ‐/‐ 32.5%: p = 0.0108), extrahepatic recurrence (29.3% vs. 6.5%, 9.7%, or 5.0%: p = 0.0026), and no treatment at recurrence (29.3% vs. 9.7%, 9.7%, or 5.0%: p = 0.0115). These results indicate that the tumor markers AFP and DCP are significant prognostic factors for recurrent HCC, and their monitoring is essential for improving the prognosis after recurrence.
Functional Maps of Metastases from Breast Cancers: Proof of the Principle that Multidimensional Scaling Can Summarize Disease Progression
Authors: Gray Lincoln C. , Vaidya Jayant S. , Baum Michael , Badwe Rajendra A. , Mittra Indraneel , Siddiqui Tariq , Wiarda Dorothea 
Published: June 2004

AbstractThe mathematic technique of multidimensional scaling can create “functional maps” of metastases from breast cancer such that positions of organs in these maps are proportional to the probability of metastases. Areas that are likely to share disease are close together in a functional map, even though they may be physically distant, and vice versa. Two functional maps of breast cancers—one of local metastases to axillary levels I to III and another of distant metastases—are statistically significant and clinically meaningful. The maps accurately reflect the clinical data (r > 0.97, p < 0.01), and so the progression of disease is revealed in simple visual summaries. As an analogy, the metastatic sites are like buoys on a fluid surface, and cancer spreads from a primary tumor like waves emanating from a point of impact on that surface. Metastases are predicted when the waves swamp the buoys. Because breast cancers do not always spread to the next nearest site, these functional maps do not resemble anatomic maps. The maps are a view of the body as “seen” by the tumor. Several well known clinical features are seen in these maps: most local metastases are to axillary level I; upper‐inner primaries spread equally to levels II and III; in‐transit metastases in the lymph and blood vessels do not follow the pattern of other distant metastases. Future functional maps can expand these summary diagrams to include biologic parameters (gene‐expression profiles or endocrine response) and give valuable insights into patterns of recurrence in different populations.
Surgical Workload and Cost of Postoperative Adhesion‐related Intestinal Obstruction: Importance of Previous Surgery
Authors: Kössi Jyrki A.O. , Salminen Paulina T.P. , Laato Matti K. 
Published: June 2004

AbstractPostoperative intraabdominal adhesions cause morbidity of varying degree. Intestinal obstruction is the most severe complication of adhesions. This study examined the importance of previous surgery on clinical and economic workloads caused by intestinal obstruction due to postoperative intraabdominal adhesions. All emergency hospitalizations due to adhesion‐related intestinal obstruction from January 1, 1999 to December 31, 1999 in a hospital district serving roughly 450,000 inhabitants was reviewed retrospectively. The patient population was divided into six groups according to the site of previous surgery, and the total as well as group‐related surgical workload and direct costs of inpatient care were analyzed. There were 123 hospitalizations due to postoperative adhesion‐related intestinal obstruction during the study period. A total of 101 patients had experienced 176 operations. The most prevalent operations were colorectal (with or without other operations), upper abdominal, and female reproductive system procedures. Colorectal surgery preceded 40% and 38% of inpatient episodes and inpatient days, respectively. Altogether, 40 operations were performed because of adhesion‐related intestinal obstruction. No differences between groups were seen in terms of the mean operating or theater time. Total annual inpatient costs due to emergency hospitalizations for intestinal adhesion‐related obstruction related to colorectal surgery in a hospital district serving roughly 450,000 inhabitants was $72,520.60 (U.S. dollars) which accounted for 35.3% of all annual costs caused by postoperative adhesion‐related intestinal obstructions. There were no significant differences between groups regarding the total mean inpatient episode costs. Intestinal obstruction due to postoperative adhesions poses substantial costs for the society. Colorectal operations are the most important procedures preceding adhesion‐related intestinal obstruction, accounting for 35.3% to 46.8% of the total clinical workload or costs attributable to postoperative adhesion‐related obstruction.
2'‐Functionalized Nucleic Acids as Structural Tools in Molecular Biology
Authors: Zatsepin Timofei S. , Gait Michael J. , Oretskaya Tatiana S. 
Published: June 2004

AbstractModified oligonucleotides bearing 2'‐reactive groups or 2'‐conjugated molecules have found wide application as structural tools in molecular biology. Of principal interest has been the use of 2'‐reactive oligonucleotides for cross‐linking with biomolecules and of 2'‐conjugated oligonucleotides in hybridization assays. In this review we compare a range of electrophilic, nucleophilic and photoreactive groups for cross‐linking and conjugation studies.
IUBMB Life, 56: 209‐214, 2004
On the shapes of Newton's revolving orbits
Authors: Lynden-Bell D. , Lynden-Bell R. M. 
Published: June 2004

Newton's beautiful theorem on revolving orbits is described in propositions 43 and 44 of
Principia
. From Motte's translation revised by Cajori (see also Chandrasekhar, who first drew our attention to this theorem).

43. It is required to make a body move in a curve that revolves about the centre of force in the same manner as another body in the same curve at rest
4. The difference of the forces by which two bodies may be made to move equally, one in a fixed, the other in the same orbit revolving varies inversely as the cubes of their common altitudes (radii).
Those who read these propositions without consulting the expositions that follow them are likely to believe that Newton was considering two orbits, the first in fixed axes and the second in uniformly rotating axes. This is not the case. Indeed, that could not be so because unless the orbits were circular, the second particle would not then sweep out equal areas in equal times relative to fixed axes, so the force could not be central. Newton's subtlety lies in choosing the rate of rotation of the axes proportional to the øof the particle in the fixed orbit, where ø is the azimuth. With that construction the second particle, when seen from fixed axes, sweeps in equal times equal areas proportional to those swept by the first.
A Keplerian ellipse in fixed axes will generate the same ellipse in Newton's nonuniformly rotating axes when we add an inverse cube force. But what shape will that ellipse make relative to axes rotating uniformly at the same mean rate as Newton's?