bluuebunny/crossref_metadata_2025_split huggingface dataset:
Colorectal carcinoma in children and adolescents: The experience of the Istituto Nazionale Tumori of Milan, Italy
Authors: Ferrari Andrea , Rognone Alessia , Casanova Michela , Zaffignani Elena , Piva Luigi , Collini Paola , Bertario Lucio , Sala Paola , Leo Ermanno , Belli Filiberto , Gallino Gianfranco 
Published: April 2007

AbstractBackgroundColorectal carcinoma (CRC) is one of the most common tumors in adults, but extremely rare in young age. This study retrospectively reports on a group of 27 patients <30 years of age, and particularly on 7 cases <18 years old, treated at the Istituto Nazionale Tumori, Milan, Italy, between 1985 and 2005.Patients and MethodsAmong the children/adolescents (age 9–18, median 12 years), 5/7 had unfavorable CRC histotypes (poorly differentiated or mucinous adenocarcinoma) and all but one had advanced disease at onset. Initial surgical resection was complete in 5/7 cases, and all patients received postoperative chemotherapy.ResultsIn the subset of patients <18 years, 6/7 had tumor progression or relapse, and 5 died of their tumor: overall survival (OS) was 23% at 5 years. In the group of 19‐ to 29‐year‐olds (young adults), 5‐year OS was 72.6%.ConclusionsThis study confirms the rarity and poor prognosis of CRC in children and adolescents: advanced stage and an aggressive biology are hallmarks of this tumor in pediatric age, while clinical findings and outcome in young adults seem more similar to those observed in adult series. Therapeutic recommendations should stay the same as for adults. Surgery remains the mainstay of treatment and early diagnosis is crucial: it is important for pediatricians to be aware that CRC does occur in children, in order to refer suspected cases to expert physicians professionally dedicated to the management of this cancer in adults. Pediatr Blood Cancer 2008;50:588–593. © 2007 Wiley‐Liss, Inc.
Temperature Drop Turbidimetry as a Means for the Rapid Determination of the Polydispersity of Polymers Part III. Polyethylene
Authors: Hay James N. , Wiles Michael 
Published: April 2007

AbstractThe molecular weight averages of narrow and broad distribution polyethylene have been determined by controlled precipitation from a mixed solvent of xylene/n‐hexanol in the temperature range 433 to 33K. Estimates of the distribution (D) which compared unfavourably with and considerably under‐estimated those determined by gel permeation chromatography (g.p.c.) were obtained by a calibration procedure between the temperature of initial onset of precipitation and the weight average molecular weight which have been used previously 1,2 to characterise turbidimetric curves. However, the calibration curves gave an accurate estimate of the weight average molecular weight. There was also an accurate correlation between the reciprocal of the breadth of the turbidity‐temperature curves as measured by 1/Tmax (dτ/dT) −1 i.e. (S)−1, and the logarithm of the g.p.c. dispersity which enabled the breadth of distribution to be determined. With these two correlations molecular weight characteristics could be determined rapidly which compared favourably with g.p.c. data. The method has been applied to fractions obtained for 3 methods of fractionating polyethylene in order to compare their relative efficiencies.
A comparison of the thermal stabilities of a siloxane substituted polycarbonate with a standard polycarbonate and a polydimethylsiloxane
Authors: Knight Graham J. 
Published: April 2007

AbstractThe thermal stability in inert and oxidising atmosphere of an aromatic polycarbonate with a siloxane side chain has been compared with those of a polycarbonate and a poly‐(dimethylsiloxane) using thermogravimetry. The presence of the siloxane side chain is seen to marginally enhance the thermal stability compared to that of the unsubstituted polycarbonate.
Lower Critical Solution Temperatures, Part II Polymethylene in binary n‐alkane solvents
Authors: Kodama Yoshinori , Swinton Findlay L. 
Published: April 2007

AbstractThe lower critical solution temperatures (LCST) were measured visually for linear polymethylene in twelve different binary solvents composed of various n‐alkane pairs ranging from n‐hexane to n‐hexatriacontane (C36). A reasonable correlation is found between the experimental LCST's of these pseud o‐ternary systems and the gas‐liquid critical temperatures of the binary solvents.Full thermodynamic data are available for only one of these systems, polymethylene/ n‐hexane/n‐octane and it is found that one version of the Flory theory predicts the experimental LCST's for this mixture with acceptable accuracy. No adjustable parameters are required.
Load Bearing Polymers used in Orthopaedic Surgery
Authors: Hastings Garth W. 
Published: April 2007

AbstractOne of the major contributions to orthopaedic surgery has been the use of ultra‐high‐molecular‐weight polyethylene in prosthetic joint replacements. The part played by this polymer is set in the context of biomechanical requirements. Work dealing with wear found in components of knee prostheses removed from patients is presented, the main mechanism being cold flow followed by abrasive wear. Surface delamination and the effect of inhomogeneous regions are described. Polyacetals, homo and copoly mers are being used as bearing surfaces and the current position is reported. Work in the author's laboratory to develop carbon fibre reinforced plastics is described briefly. The development of Standards is mentioned.
The influence of residual styrene monomer, benzaldehyde, and microbial activity on the surface properties of polystyrene latices
Authors: Wilkinson Michael C. , Sherwood Roger , Hearn John , Roy Goodall A. 
Published: April 2007

AbstractThe influence of residual styrene monomer and benzaldehyde on the surface properties of polystyrene latices has been considered. These materials are commonly found after emulsion polymerisation and their complete removal by dialysis is almost impossible. Steam stripping at reduced pressure (nitrogen atmosphere, < 350K) can be used to remove the last traces of styrene and benzaldehyde from polystyrene, but this process results in some degree of hydrolysis of the surface sulphate groups.Latices are easily contaminated by microorganisms, especially those which are airborne. This can occur during cleaning and/or storage. Microorganisms can survive and multiply in suitable latex environments and can result in the destabilisation and subsequent flocculation of the latex. Controlled experiments with a latex dosed with various levels of a penicillium type fungus demonstrated the possibility that enzymes (classified as aryl sulphate sulphohydrolases ‐ E. C. 3.1.6.1.) were produced which resulted in the rapid hydrolysis of surface sulphate groups. Fungal growth was accompanied by the release of weak acids and metabolites which were titrated in the aqueous phase.Careful consideration should be given to the conditions of latex preparation, cleaning and storage, e.g. use of autoclaved water and γ‐irradiation techniques, which will reduce the possibility of microbial contamination. Routine tests for bacteria and fungi should be carried out by plating on microbiological media, since the usual tests for protein such as the Folin‐Ciocalteu are insensitive at the low levels of contamination which may be present.
Contribution to pivalolactone polymerisation
Authors: Bier Gerard , Vollkommer Norbert 
Published: April 2007

AbstractThe bulk polymerisation of pivalolactone (PVL) has been investigated using tertiary and quaternary phosphorus compounds as initiators. The quaternary P‐compounds were found to be essentially more active than the tertiary ones.The polymerisation mechanism with the two classes of initiators is as follows: Tertiary phosphines (and amines) form zwitterions and macro‐zwitterions with PVL, or: positive and negative charges are fixed on the same macromolecule. By chain transfer agents a separation of the charges onto two molecules takes place; the zwitterion character disappears.Using quaternary phosphonium (ammonium) compounds the anion starts the reaction; it is built into the polymeric chain. The gegenion retains its low molecular weight during the entire propagation reaction. During this stage an anion of high and a cation of low molecular weight are present side by side. The mechanism is not changed by any chain transfer reaction.The different reaction rates during propagation in the presence of these initiators are explained on one hand by a macrocation and on the other hand by a cation of low molecular weight. The degree of dissociation, which is higher in quaternary compounds than in tertiary ones, might also influence the reaction. The initiator molecule influences the start reaction as well as the total propagation reaction.
Epoxide resins as adhesives: Past and present
Authors: Garnish Edward W. 
Published: April 2007

AbstractEpoxide resins were introduced commercially thirty‐three years ago. One of the first formulations was an adhesive. There has been continuous development of the systems since then based on an increasing range of materials used in their constitution and an increasing knowledge of their chemistry and cured properties. This paper examines some of the scientific topics that contribute to the present day knowledge of these high strength adhesives and that are now used when advances are sought in the technology.
Some problems associated with the application of thermal methods to polymers
Authors: Still Richard H. 
Published: April 2007

AbstractThe scope of thermal methods and their application to polymeric substrates are reviewed. The general application of these methods to polymers is discussed and illustrated by reference to: (i) the problems associated with thermal methods and the apparatus used to obtain thermal responses; (ii) the problems associated with calibration and the standardisation of reporting procedures; (iii) the specific problems associated with polymeric materials. Problems associated with crystallinity determinations and thermal stability assessment are also discussed.
Crystallisation kinetics and melting studies
Authors: Hay James N. 
Published: April 2007

AbstractMethods for determining the crystallisation characteristics of polymer by differential scanning calorimetry are discussed, particularly in terms of their limitations. Isothermal and non‐isothermal crystallisation thermogrphs are analysed to determine crystallisation mechanism and compared with other techniques. The inadequacies of current theories of crystallisation rates are developed. Melting studies on oligomers and polymers are developed in terms of recent theories of melting, and a method suggested for quantifying the quality of crystallinity in polymeric material in terms of the averages of the lamellae thickness.
The reaction of dimethyldichlorosilane with polyorganosiloxanes derived from pseudowollastonite
Authors: Atwal Rajinder , Bola Tarlok S. , Cook Colin B. , Currell Brian R. , Midgley Henry G. , Parsonage John R. 
Published: April 2007

AbstractThe interaction of dimethyidichlorosilane with polyorganosiloxanes prepared by the trimethylsilylation of mineral silicates is catalysed by ferric chloride hexahydrate and results in the formation of higher molecular weight polyorganosiloxanes and also trimethylchlorosilane. The nature of the products and particularly the molecular weight depends on the relative amounts of reactants. It is also shown that during the course of the reaction a substantial proportion of the ferric chloride is reduced to ferrous.
Thermotropic liquid‐crystalline polyesters and polyesteramides
Authors: McIntyre James E. , Milburn Alexander H. 
Published: April 2007

AbstractThermotropic behaviour is observed in a number of aromatic polyesteramides containing p‐phenylene or substituted p‐phenylene groups. In such polymers, a substantial proportion of co‐polymerised units lacking rigid rod structure can be tolerated without loss of thermotropic behaviour. Anisotropic melts can be formed at very short average chain length. The upper temperature limit of stability of the anisotropic phase is lower the shorter the average chain length and the greater the proportion of relatively flexible units. Some polyesteramides formally derived from p‐N‐methylaminophenol also exhibit thermotropic behaviour.
The determination of active centres in olefin polymerisation
Authors: Caut Anthony D. 
Published: April 2007

AbstractThe kinetics of Ziegler‐Natta polymerisations can be described in terms of a spectrum of active sites, each with differing propagation rates and stereospecificity. It is therefore necessary to use complementary methods of measuring active centres to get the whole picture. Higher activity in polymerisation of propylene using TiCl3 ‐ Et2AlCl systems can be achieved by varying the catalyst preparation so that the effective surface area is increased or by removing inhibitors. When Et3Al is used as activatior in place of Et2 AlCl higher activity is due to a combination of increase in number of centres per mole TiCl3 and of increase in their propagation rate.
Condensation polymerisations with unequal reactivity in segregated continuous‐flow stirred tank reactors
Authors: Gupta A. Sen , Kumar Anil , Gupta Santosh K. 
Published: April 2007

AbstractA parametric study of the molecular weight distribution and its moments has been made on the irreversible condensation polymerisation of ARB type monomers which do not obey the equal reactivity hypothesis. The reactions are simulated for a continuous‐flow stirred‐tank reactor with distributed residence times, the mean residence time being the operating variable. Two different kinetic schemes have been proposed which represent the limiting cases of the actual situations (models I and II) which are usually encountered and the effect of segration in a CSTR has been studied. The molecular weight distributions, number average chain lengths and the polydispersity indices have been computed. Results are found to lie intermediate between batch reactors and homogeneous, continuous‐flow stirred tank reactors. Plots between the poly dispersity index and the monomer conversion with the reactivity ratio, R, and the number average chain length as parameters indicate that results are far more sensitive to variations in R for model II than for model I.
Thermal degradation of methyl and ethyl cyanoacrylate oligomers
Authors: Rooney John M. 
Published: April 2007

AbstractThermal degradation of methyl and ethyl cyanoacrylate polymers of number‐average molecular weights 370–1350 is shown to proceed by depolymerisation at temperatures in the range 140°–180°C. Under the conditions of the thermogravimetric analysis technique employed, weight loss kinetics appear to be governed by diffusion of monomer vapour through the liquid sample. A mathematical model of this process is postulated.
Dispersing silicon nanoparticles in a stirred media mill – investigating the evolution of morphology, structure and oxide formation
Authors: Reindl A. , Aldabergenova S. , Altin E. , Frank G. , Peukert W. 
Published: April 2007

AbstractSilicon nanoparticles were dispersed for 24 hours in 1‐butanol using a stirred media mill. Via this process intrinsically stable suspensions (in regard to aggregation) of Si nanoparticles were produced after 6 hours of dispersing. The evolution of morphology, particle size and structure was investigated by dynamic light scattering, X‐ray diffraction, Raman spectroscopy and high resolution transmission electron microscopy as a function of dispersing time. The average crystallite size decreased from about 18 nm down to about 10 nm within 24 hours of milling as determined by X‐ray diffraction and Raman scattering measurements. In addition careful analysis of the Raman spectra revealed a decrease of the crystalline volume fraction from 75% down to 24% and a corresponding increase of the amorphous phase. The microstructural development with varying crystallite size and crystalline volume fraction was directly confirmed by transmission electron microscopy measurements. Elemental analysis showed an increase of oxygen content that was directly proportional to the increase in specific surface area of the silicon nanoparticles during the dispersing process. The surface chemistry of the Si nanoparticles was analyzed by diffuse reflectance infrared Fourier transform spectroscopy that indicated vibrational bands of HSi–Si3–x Ox , SiOx , and residual 1‐butanol. The final product of the dispersing process seems to be a two‐phase mixture of amorphous Si and Si nanocrystallites covered with SiOx on the surface. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of annealing temperature on the electrical transport properties of CaRuO3–δ thin films directly deposited on the Si substrate
Authors: Paik Hanjong , Kim Youngha , No Kwangsoo , Cann David P. , Yoon DongJoo , Kim ByungIl , Kim Yangsoo 
Published: April 2007

AbstractWe investigate the effect of annealing temperature on the preferentially (110)‐oriented CaRuO3–δ (CRO) thin films directly prepared on Si(100) substrate by rf magnetron sputtering. Crystalline quality and electrical transport properties of the CRO thin films were modified by post‐annealing treatment. It was obvious that 700 °C post‐annealing brought about excellent metallic characteristics with the elevation of carrier concentration and mobility. From this result, we suggested that enhanced (110) orientation, and the ratio of chemical composition Ru4+/Ca2+ ion were responsible for the transport properties of CRO thin film. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of lyophilized extracts from guaraná seeds [Paullinia cupana var. sorbilis (Mart.) Ducke] on behavioral profiles in rats
Authors: Otobone F. J. , Sanches A. C. C. , Nagae R. , Martins J. V. C. , Sela V. R. , Mello J. C. P. de , Audi E. A. 
Published: April 2007

AbstractThe aim of the present study was to investigate the pharmacological properties of the crude lyophilized extract (EBPC) of Paullinia cupana seeds (guaraná) and the semi‐purified extracts (EPA and EPB) after acute or chronic administration by the oral route in rats. Anxiolytic‐like, antidepressant‐like and motor stimulant effects were evaluated using the plus maze (PMT), forced swimming (FST) and open field (OFT) tests, respectively. Acute or chronic administration of EBPC (3.0, 30.0 or 60.0 mg/kg) did not alter the percentage of entries or the time spent in the open arm in the PMT. In the FST, chronic treatment with 30.0 mg EBPC/kg and 4.0 mg EPA/kg extract decreased the immobility time similarly to the antidepressant reference drug, imipramine (20.0 mg/kg). Locomotor activity in the OFT was not increased by these extracts. Caffeine (10.0 mg/kg) significantly reduced the immobility time in the FST, but increased locomotor activity in the OFT, indicating psychostimulant activity. The EPB extract did not induce any effect after acute or chronic treatment in the different models used. The present results suggest that the crude EBPC extract and EPA extract produced an antidepressant‐like effect after long‐term administration. Copyright © 2007 John Wiley & Sons, Ltd.
Are herbs always good for you? A case of paralytic ileum using a herbal tisane
Authors: Sossai Paolo , Nasone Cinzia , Cantalamessa Franco 
Published: April 2007

AbstractWe believe that administration of phytotherapics (‘herbal’ medicines) should be managed by physicians and pharmacists who can monitor any adverse reactions including allergies in patients. This of course implies that physicians and pharmacists require adequate training at the university and post‐university level regarding all aspects of medicinal plants.We report here a case of paralytic ileum occurring in an older self‐medicated patient who acquired an herbal tisane composed of Cassia angustifolia, as well as other plant products, in an herbal shop, for chronic constipation. Copyright © 2007 John Wiley & Sons, Ltd.
Isolation of antileishmanial sterol from the fruits of Cassia fistula using bioguided fractionation
Authors: Sartorelli Patrícia , Andrade Samanta P. , Melhem Márcia S. C. , Prado Frederico O. , Tempone André G. 
Published: April 2007

AbstractNatural products represent a rich source of new chemical entities for the development of drugs for neglected diseases. Leishmaniasis still afflicts the poorest populations in the world, with 12 million cases worldwide. This work analysed crude extracts and fractions from the fruits of Cassia fistula against the most dramatic and fatal disease form of leishmaniasis, the visceral form (VL). Hexane extract from the fruits showed significant antileishmanial activity against the promastigote form of Leishmania L. chagasi. The bioguided fractionation resulted in the isolation of a sterol, clerosterol, which was further analysed in different models. Promastigotes presented an inhibitory concentration 50% (IC50) of 10.03 µg/mL and intracellular amastigotes demonstrated high susceptibility, with an IC50 of 18.10 µg/mL. Mammalian cytotoxicity was evaluated and it was demonstrated that clerosterol was 3.6‐fold less toxic than the standard drug pentamidine. No antifungal activity of the isolated clerosterol was found. Future studies of the extracted compounds of Cassia fistula could be a useful tool for the development of new therapeutic agents for VL. Copyright © 2007 John Wiley & Sons, Ltd.
Rapid structural determination of amides in Piper longum by high‐performance liquid chromatography combined with ion trap mass spectrometry
Authors: Sun Cuirong , Pei Saifeng , Pan Yuanjiang , Shen Zhiquan 
Published: April 2007

AbstractA reversed‐phase liquid chromatography/tandem multistage mass spectrometry (MS/MS) method was developed for the characterization of amides from the extracts of Piper longum. The characteristic fragmentations of the amides found in P. longum showed diagnostic structural information. Extracted ion chromatography (EIC) and constant neutral losses were used to guide the search for the amides of interest. Amides of known structures that contain four subtypes of amides were rapidly determined, and novel amides were also identified for this plant. Forty‐two amides were rapidly identified, of which 22 were found in this plant for the first time and 9 were new compounds. The method is convenient and sensitive, especially for minor components in the unpurified, complex mixture; the structures of unknown constituents could be determined, in the absence of authentic sample, by comparison of the fragmentation patterns with those of homologous compounds. Copyright © 2007 John Wiley & Sons, Ltd.