bluuebunny/crossref_metadata_2025_split huggingface dataset:
Technical note on a much simplified method for collecting ruminal fluid using a nylon paint strainer
Authors: Leyendecker Sandra A , Callaway Todd R , Anderson Robin C , Nisbet David J 
Published: February 2004

AbstractCollection of ruminal fluid for in vitro experimentation has traditionally been accomplished by straining rumen digesta through multiple layers of cheesecloth or other cumbersome filtering materials, such as surgical gauze, nylon tissues or wire gauzes. We here report a comparison of the gross physical, fermentative and microbial characteristics of ruminal fluid collected by straining through cheesecloth or through a nylon mesh paint strainer that, because of its pouched shape, is conveniently filled with digesta thus making the collection and straining process much easier. Whether strained through cheesecloth or the nylon mesh strainer, ruminal fluid did not differ (P > 0.05) in dry matter, neutral or acid detergent fiber content or in concentrations of total culturable anaerobes. Total amounts (mM) of volatile fatty acid or ammonia produced after 24 h of incubation of cheesecloth‐ or nylon mesh‐strained ruminal fluid with added tryptose, SigmaCell 50 or starch did not differ (P > 0.05) thus indicating that the microbial populations within the strained fluids possessed similar abilities to ferment these test substrates. Because the physical, fermentative and microbial characteristics of the nylon mesh‐ and cheesecloth‐strained ruminal fluid were essentially equivalent, we conclude that the much easier to use nylon mesh strainers can be incorporated into a faster, more convenient ruminal fluid straining method. Published in 2004 for SCI by John Wiley & Sons, Ltd.
Acrylonitrile‐Acrylic Acid Copolymer Membrane Imprinted with Uric Acid for Clinical Uses
Authors: Cristallini Caterina , Ciardelli Gianluca , Barbani Niccoletta , Giusti Paolo 
Published: February 2004

AbstractSummary: The preparation of new polymeric membranes using molecular imprinting technology for application in blood filtration devices is described. Membranes, based on an acrylic acid‐acrylonitrile copolymer, produced through phase inversion, were modified by introducing specific binding sites for uric acid into their structure. The materials prepared are intended for use to selectively remove uric acid from the blood in the case of increased serum uric acid values associated with different pathologies. The interactions at a molecular level between the membrane forming copolymer and the template were investigated by means of calorimetry, infrared spectroscopy and morphological analysis. The presence of interactions between the template and the copolymer, and a good thermal stability of the imprinted membranes were observed. In addition, the results of rebinding tests on the imprinted membranes indicated a good capacity of molecular recognition for the template and satisfactory selectivity properties towards compounds of similar structure such as theophylline. Membrane permeability values suggest their application as (ultra) haemofiltration devices.Poly(acrylonitrile‐co‐acrylic acid) membrane.imagePoly(acrylonitrile‐co‐acrylic acid) membrane.
Spherical Molecularly Imprinted Polymers (SMIPs) via a Novel Precipitation Polymerization in the Controlled Delivery of Sulfasalazine
Authors: Puoci F. , Iemma F. , Muzzalupo R. , Spizzirri U. G. , Trombino S. , Cassano R. , Picci N. 
Published: February 2004

AbstractSummary: Spherical molecularly imprinted polymers (SMIPs) have been prepared via a novel precipitation polymerization using sulfasalazine (prodrug used in the diseases of the colon) as template. The sulfasalazine was incorporated into SMIPs and into a spherical non‐imprinted polymer (control), and then the release rate of the bioactive agent at different pH values was evaluated. Considerable differences in the release characteristics between imprinted and non‐imprinted polymers have been observed. This opens the possibility of the development of drug release systems capable of modulating the release of a specific molecule.Photomicrography of spherical molecularly imprinted polymers (SMIPs).imagePhotomicrography of spherical molecularly imprinted polymers (SMIPs).
Effect of Drug‐loading Methods on Drug Load, Encapsulation Efficiency and Release Properties of Alginate/Poly‐L‐Arginine/Chitosan Ternary Complex Microcapsules
Authors: Wang Shi‐Bin , Chen Ai‐Zheng , Weng Lian‐Jin , Chen Mei‐Ying , Xie Xiao‐Lin 
Published: February 2004

AbstractSummary: The drug‐loaded alginate/poly‐L‐arginine/chitosan ternary complex microcapsules were prepared by mixing method, absorption method and the combined method of mixing and absorption, respectively. The effect of drug‐loading methods on drug load, the encapsulation efficiency and the release properties of the complex microcapsules were investigated. The results showed that the absorption process is a dominating factor to greatly increase the drug load of Hb into microcapsules. Upon loading Hb into microcapsules by combined method of mixing and absorption, the drug load (19.9%) is up to the maximum value, and the encapsulation efficiency is 93.8%. Moreover, the drug release is a zero‐order kinetics process for the ternary complex microcapsules made by mixing. For the complex microcapsules made by absorption, the drug release is a first‐order kinetics. However, for the complex microcapsules made by combining the mixing and the absorption, the drug release obeys a first‐order kinetics during the first eighteen hours, changing afterwards to a zero‐order kinetics process.Effect of drug‐loading methods on drug load and encapsulation efficiency of alginate/poly‐L‐arginine/chitosan ternary complex microcapsules.imageEffect of drug‐loading methods on drug load and encapsulation efficiency of alginate/poly‐L‐arginine/chitosan ternary complex microcapsules.
Preparation and Characterization of Biodegradable Microspheres Containing Hepatitis B Surface Antigen
Authors: Zhou Shaobing , Liao Xueyan , Liang Zhenglun , Li Xiaohong , Deng Xianmo , Li Heming 
Published: February 2004

AbstractSummary: Poly‐DL‐lactide‐poly(ethylene glycol) (PELA) microspheres containing Hepatitis B surface antigen (HBsAg) were elaborated by a solvent extraction method based on the formation of a double water/oil/water (w/o/w) emulsion. Microspheres were characterized in terms of morphology, size and size distribution, encapsulation efficiency, and the efficiency of microsphere formation (EMF). Transmission electron microscopy (TEM) and polyacrylamide gel electrophoresis (PAGE) were used to investigate the structural integrality of HBsAg encapsulated in PELA microspheres. The release profile was investigated by the measurement of antigen present in the release medium at various intervals. The PELA‐10 microspheres displayed the highest antigen encapsulation efficiency (about 80%), and antigen molecules could be stabilized in the PELA‐10 microspheres during the preparation process. It suggested that the PELA microspheres had a great potential as a new polymer adjuvant for HBsAg.The release of Hepatitis B surface antigen from poly‐DL‐lactide‐poly(ethylene glycol) microspheres.imageThe release of Hepatitis B surface antigen from poly‐DL‐lactide‐poly(ethylene glycol) microspheres.
High Activity of Enzymes Immobilized in Colloidal Nanoreactors
Authors: Neumann Thorsten , Haupt Björn , Ballauff Matthias 
Published: February 2004

AbstractSummary: We present a novel type of nanoreactor suitable for the immobilization of enzymes. The particles used consist of a polystyrene core onto which long chains of poly(acrylic acid) are grafted (“spherical polyelectrolyte brush”). Proteins adsorbed spontaneously onto these particles from aqueous solutions if the ionic strength is low. We immobilized glucoamylase on these particles and showed that this enzyme keeps nearly its full activity. This is shown by analyzing the enzymatic activity in terms of the Michaelis‐Menten kinetics. No leaching out of the enzyme takes place during the reaction and the colloidal stability is not impeded by the adsorbed biomolecules. The data presented here suggest that the principle of immobilizing enzymes on these particles may be of general use.The Figure shows a schematic representation of the colloidal nanoreactors.imageThe Figure shows a schematic representation of the colloidal nanoreactors.
Fabrication of Honeycomb‐Patterned Cellulose Films
Authors: Kasai Wakako , Kondo Tetsuo 
Published: February 2004

AbstractSummary: This paper reports for the first time on the fabrication of honeycomb‐patterned cellulose films by casting water in oil emulsion of cellulose acetate onto a glass substrate and subsequent deacetylation treatment. The honeycomb pore size could be controlled from 1 to 100 μm under a saturated water vapor condition. Both cellulose and cellulose acetate films with honeycomb‐pattern are expected to be a two‐dimensional model of plant cell walls as well as of micro‐wells for single cell cultivation.Surface topographic image of a honeycomb‐patterned cellulose film (scalebar: 50 μm).imageSurface topographic image of a honeycomb‐patterned cellulose film (scalebar: 50 μm).
Association of Calcium Phosphate and Fibroblast Growth Factor‐2: a Dynamic Light Scattering Study
Authors: Onuma Kazuo , Kanzaki Noriko , Kobayashi Naoko 
Published: February 2004

AbstractSummary: The size distributions of fibroblast growth factor‐2 (FGF‐2) in aqueous solutions with neutral pH were investigated with a dynamic light scattering technique. We found that the FGF‐2 was distributed in dimer or trimer form at concentrations of 0.1–1.0 mg · mL−1. An aggregate with a hydrodynamic radius of approximately 90 nm coexisted with this and its proportion increased with a decrease in concentration. At lower concentrations (less than 0.10 mg · mL−1) FGF‐2 aggregates with an average radius of 80–100 nm were dominant and were stable for more than a day. These FGF‐2 solutions were mixed with calcium phosphate solutions to produce a sub‐micron sized compound of FGF‐2 and hydroxyapatite, which could be used as a biological implant that possessed a pharmacological function for bone formation. By utilizing a transformation from amorphous calcium phosphate to hydroxyapatite, FGF‐2 was effectively incorporated into polycrystals of hydroxyapatite.SEM photograph of a mixture of hydroxyapatite and FGF‐2.imageSEM photograph of a mixture of hydroxyapatite and FGF‐2.
Cover Picture: Macromol. Biosci. 1/2004
Authors: Kasai Wakako , Kondo Tetsuo 
Published: February 2004

Cover: This picture shows the 2‐dimensional image and the surface topographic image (inset) of a honeycomb‐patterned cellulose acetate film, obtained by mild alkali‐treatment of the cellulose acetate film without deformation of the structural pattern. The pore size of the honeycomb‐pattern in the cellulose films could be controlled from 1 to 100 μm.Further details can be found in the Communication by W. Kasai, T. Kondo* on page 17.
Electromechanics of a Chiral Smectic C Elastomer: Measurement of Complex Piezoelectric Constant through Successive Phase Transformations
Authors: Hiraoka Kazuyuki , Stein Peter , Finkelmann Heino 
Published: February 2004

AbstractSummary: Piezoelectric properties of a chiral smectic liquid crystalline elastomer are investigated by means of dynamic electromechanical measurements. We have confirmed that the piezoelectric constant is fairly large in the chiral smectic C (SmC*) phase. A relaxation of the piezoelectric constant is observed in the frequency dispersion curve of a director orientated elastomer obtained by a uniaxial deformation. The temperature dependence of the relaxation frequency in the smectic phases is nicely fitted to the Vogel‐Fulcher‐Tammann law, because the dynamics observed here is closely related to the glass transition phenomena. A resonance instead of a relaxation is recognized in the case of a biaxial deformed elastomer in which both layer and director are oriented to their preferred directions. In addition, the piezoelectric constant of the biaxially deformed elastomer possessing a macroscopically spontaneous polarization is smaller than that of the uniaxially deformed elastomer with no net spontaneous polarization. We discuss the mechanism of polarization generation in the electromechanical response of the SmC* elastomers, and also consider the emergence of the resonance in the biaxial deformed elastomer.Geometry of sample deformation.imageGeometry of sample deformation.
Radical Polymerisation of 1H,1H,2H,2H‐perfluoro‐3,5‐alkyldiynol and 1H,1H‐perfluoro‐2,4‐alkyldiynol Acrylates and Methacrylates: A New Family of Fluorinated Polymers
Authors: Estelrich Ana Robert , Ameduri Bruno , López‐Calahorra Francisco 
Published: February 2004

AbstractSummary: The preparation of a new family of acrylic esters with a perfluorinated chain directly bonded to one or two conjugated triple bonds from 1H,1H,2H,2H‐perfluoro‐3,5‐alkyldiynol and 1H,1H‐perfluoro‐2,4‐alkyldiynol is reported. Their solution homopolymerisation was studied in the presence of a radical initiator and it was found that the polymerisation process bore more similarity to that observed with the analogous hydrocarbonated monomers containing triple bonds rather than that observed with polyfluorinated monomers without any alkyne groups. Furthermore, under the reaction conditions used, the triple bonds remained unchanged as there was no cross‐linking process. The homopolymers obtained were characterised by NMR, infrared spectroscopy and gel permeation chromatography whenever possible.Structure of new fluorinated homopolymers.imageStructure of new fluorinated homopolymers.
Thermoresponsive Properties of Sugar Sensitive Copolymer of N‐Isopropylacrylamide and 3‐(Acrylamido)phenylboronic Acid
Authors: Shiomori Koichiro , Ivanov Alexander E. , Galaev Igor Yu. , Kawano Yoshinobu , Mattiasson Bo 
Published: February 2004

AbstractSummary: The copolymer of N‐isopropylacrylamide and 3‐(acrylamido)phenylboronic acid (82:18, $\overline M _{\rm n}$ = 47 000 g · mol−1) was prepared by free radical polymerization. The copolymer showed typical thermal precipitation behavior in aqueous solutions, its precipitation temperature (TP) being increased from 23 to 32 °C by increasing the pH from 6.5 to 9.7, because of ionization of the phenylboronate units. The pKa was evaluated as 8.9 ± 0.1 from the effect of pH on TP. At pH > 9, i.e., in the anionic form of the copolymer, TP was affected by a very low concentration of glucose (5.6 μM, ΔTP = 1–1.5 °C), because of complex formation with a high binding constant. At a higher concentration of polyols (560 μM, pH > 8) the increase of TP was maximal for the copolymer complexes with fructose (7–10 °C) and decreased in the order: fructose > glucose ≈ mannitol > pentaerythritol > galactose > Tris >glycerol. Di‐ and oligosaccharides (lactose, sucrose, and dextran) caused a slight increase of TP at pH 7.5–8.7 while no effect was observed at pH > 9. Isothermal dissolution of the copolymer suspension in water (27 °C, pH 8.5) was possible in the presence of fructose or mannitol but required higher concentrations (1.4–3.6 × 103 μM) as compared to those which enabled the shift of TP in the soluble copolymer. The dissolution rate increased with fructose concentrations.Effect of pH on TP of poly(NIPAAM‐co‐AAPBA) in the presence of various monosaccharides.imageEffect of pH on TP of poly(NIPAAM‐co‐AAPBA) in the presence of various monosaccharides.
Self‐assemblies Based on Poly(4‐diazonium styrene)
Authors: Yang Zhaohui , Cao Weixiao 
Published: February 2004

AbstractSummary: A series of self‐assembled photosensitive ultra‐thin films have been fabricated from poly(4‐diazonium styrene) (PDS) via different driving forces, mainly by electrostatic and H‐bonding interaction. Under exposure of UV light, the weak ionic and H‐bonds between the layers of the film will be converted to covalent bonds through a photoreaction. Thus, the stability of the film towards polar solvents is reinforced greatly.UV‐vis spectra of the PDS‐MPR film with different bilayers.imageUV‐vis spectra of the PDS‐MPR film with different bilayers.
Nitroxide‐Mediated Radical Polymerization with Bisaminooxy Compounds as Initiators – Controlled Biradical Polymerization
Authors: Bothe Marc , Schmidt‐Naake Gudrun 
Published: February 2004

AbstractSummary: The bisaminooxy compounds Bis‐TEMPO and Bis‐TIPNO derived from 2,2,6,6‐tetramethyl‐piperidine‐1‐oxyl (TEMPO) and 2,2,5‐trimethyl‐4‐phenyl‐3‐azahexane‐3‐oxyl (TIPNO) were applied as “biradical initiators” for the nitroxide‐mediated radical polymerization (NMRP) of styrene and n‐butyl acrylate. It was shown by comparison with analogous alkoxyamines as unimolecular initiators and mixing experiments of mono‐ and biradical species, that in the case of the biradical initiators chain growth occurs at both sides under NMRP conditions. This enables a two‐step synthesis of A‐B‐A‐triblock copolymers. Kinetics and molecular mass development were investigated for the controlled biradical polymerization of styrene at different initiator concentrations, temperatures, and with addition of acetic anhydride as accelerator. For the controlled biradical polymerization of n‐butyl acrylate with Bis‐TIPNO, the effect of added free nitroxide relative to the initiator concentration was studied. The poly(styrene‐block‐n‐butyl acrylate‐block‐styrene) copolymers with higher block length prepared by this method show two glass transition temperatures, which indicates microphase separation of the polymer blocks.Structure of poly(styrene‐block‐n‐butyl acrylate‐block‐styrene), synthesized by nitroxide‐mediated radical polymerization with Bis‐TIPNO as initiator.imageStructure of poly(styrene‐block‐n‐butyl acrylate‐block‐styrene), synthesized by nitroxide‐mediated radical polymerization with Bis‐TIPNO as initiator.
Cationic Grafting of Oxazolyl Copolymers with 2‐Methyl and 2‐Phenyl Oxazoline
Authors: Cabrera Andrés , Schmidt‐Naake Gudrun 
Published: February 2004

AbstractSummary: Commercial poly(styrene‐co‐acrylonitrile) (SAN) and poly(butadiene‐co‐acrylonitrile) (NBR) were functionalized with oxazoline groups through a reaction with 1,3‐aminoethylpropanediol (AEPD). Each of the two products, along with a third commercial poly(styrene‐co‐vinyl oxazoline) copolymer, went through a reaction with methyl triflate producing stable oxazolinium salts. The products were subsequently used as macroinitiators for the ring‐opening cationic grafting of 2‐methyl and 2‐phenyl oxazoline to produce poly(N‐acylethylenimine) grafts. The products were characterized by FT‐IR, 1H NMR and elemental analysis. The grafted fraction varied from 10 to 55 wt.‐%. The monomer units grafted onto each oxazolinium pendant group varied from 3 to 23 depending on the oxazoline substitution and concentration. The results show, firstly, that controlled and reproducible levels of poly(N‐acylethylenimine) grafts can be incorporated and, secondly, that since these results are general, they are thus applicable to a wide variety of nitrile‐containing polymers.Reaction of a nitrile group to form an oxazoline functionality.imageReaction of a nitrile group to form an oxazoline functionality.
Investigation of Soft Component Mobility in Thermoplastic Elastomers using Homo‐ and Heteronuclear Dipolar Filtered 1H Double Quantum NMR Experiments
Authors: Bertmer Marko , Gasper Lothar , Demco Dan E. , Blümich Bernhard , Litvinov Victor M. 
Published: February 2004

AbstractSummary: Information about segmental mobility in thermoplastic elastomers was obtained using static 1H double quantum (DQ) NMR experiments in combination with homo‐ and heteronuclear dipolar filters, e.g. 13C editing of 1H DQ buildup curves. Block copolymers of poly(butylene terephthalate) (PBT) as hard blocks and poly(tetramethylene oxide) (PTMO) as soft blocks (PBT‐block‐PTMO) were investigated by varying composition and block length. By simulation of the DQ buildup curves, residual dipolar couplings and with this the average order parameter were deduced for the mobile PTMO blocks which are sensitive to the segmental mobility responsible for the viscoelastic properties of thermoplastic elastomers. A strong correlation exists between residual dipolar coupling and composition. Furthermore, the average order parameter correlates linearly with the amount of PTMO in a PTMO‐rich phase as determined in previous studies. Additionally, 1H transverse magnetization relaxation measurements revealed a direct correlation between the effective T2 relaxation time of the soft domain and the composition of the thermoplastic elastomers.Correlation of the average order parameter vs. the fraction of PTMO in the PTMO‐rich phase.imageCorrelation of the average order parameter vs. the fraction of PTMO in the PTMO‐rich phase.
Synthesis of Telechelic Oligomers via Atom Transfer Radical Polymerization, 1
Authors: Otazaghine Belkacem , David Ghislain , Boutevin Bernard , Robin Jean Jacques , Matyjaszewski Kris 
Published: February 2004

AbstractSummary: Atom Transfer Radical Polymerization (ATRP) of styrene was carried out at 110 °C using various substituted 2‐bromoisobutyrates as initiators and the homogeneous catalyst CuBr/1,1,4,7,10,10‐hexamethyltriethylenetetramine (HMTETA). Telechelic oligomers were obtained by coupling the bromo terminated polymers using Cu(0)/PMDETA catalyst at 90 °C. The products were characterized by 1H NMR and MALDI‐TOF and some unsaturated polymer chains were observed. They could originate from either disproportionation reaction or dehydrohalogenation of halogen terminated oligomers during MALDI analysis. Using this method, polymers with hydroxy, acid, or ester end groups were synthesized in a range of molecular weights from 1 000 to 13 000 g · mol−1. Coupling efficiency was between 79 and 100%, depending on the structure of the initiator.Coupling reaction of substituted polystyrenes using Cu(0)/PMDETA system at 90 °C.imageCoupling reaction of substituted polystyrenes using Cu(0)/PMDETA system at 90 °C.
Photosulfonation of Low‐Density Polyethylene Films
Authors: Kaneko Masashi , Sato Hisaya 
Published: February 2004

AbstractSummary: Photosulfonation of low‐density polyethylene (LDPE) films by UV irradiation in the presence of gaseous sulfur dioxide (SO2) and oxygen (O2) was studied by attenuated total reflectance (ATR) infrared spectroscopy and X‐ray photoelectron spectroscopy (XPS). The ATR and XPS analysis and chemical modification of UV‐irradiated LDPE films demonstrated the generation of CC double bonds and sultones in the reaction. These results indicated the possibility that sulfur trioxide (SO3) was produced during the photosulfonation. New pathways for the SO3 reaction with LDPE films, resulting in the formation of sulfonic acid groups, were proposed.Overview of the mechanism proposed for the photosulfonation of low‐density polyethylene by SO3 (produced upon UV‐irradiation of gaseous SO2 and O2).imageOverview of the mechanism proposed for the photosulfonation of low‐density polyethylene by SO3 (produced upon UV‐irradiation of gaseous SO2 and O2).