bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of superabsorbent polymer with slow‐release phosphate fertilizer
Authors: Zhan Falu , Liu Mingzhu , Guo Mingyu , Wu Lan 
Published: March 2004

AbstractA superabsorbent polymer with slow‐release phosphate fertilizer was prepared by esterification of polyvinyl alcohol (PVA) and phosphoric acid (H3PO4), which was a slow‐release fertilizer at the same time. The product's water absorbency (WA) was about 480 times its own weight if it was allowed to swell in distilled water at room temperature for 24 h. WA under various conditions, such as varying the reaction time, the amount of sodium carbonate (Na2CO3), the reaction temperature, and the concentration of phosphoric acid ([H3PO4]), were investigated and optimized. The optimal sample of the product was characterized by FTIR and elemental analysis. The results showed that phosphoric groups had grafted on PVA molecule chains, and the content of P2O5 in the product was 31.2%. The water retention property and phosphate slow‐release mechanism of the product were studied as well. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3417–3421, 2004
Superabsorbent polymeric materials. XII. Effect of montmorillonite on water absorbency for poly(sodium acrylate) and montmorillonite nanocomposite superabsorbents
Authors: Lee Wen‐Fu , Yang Lin‐Gi 
Published: March 2004

AbstractA series of novel xerogels based on sodium acrylate (NaA), montmorillonite (MMT), and N,N′‐methylene‐bisacrylamide (NMBA) were prepared by inverse suspension polymerization and water solution polymerization. The influences of pure MMT, intercalated MMT, the method of polymerization, and the content of the MMT in the copolymeric gels on the water absorbency and the initial absorption rate in deionized water and various salt solutions were investigated. Results showed that the water absorbency was increased by adding a small amount of the pure MMT into the copolymeric gels, but decreased by adding intercalated MMT into the gels. In addition, the water absorbency of the gels prepared by water solution polymerization was lower than that prepared by inverse suspension polymerization. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3422–3429, 2004
Preparation and structure and mechanical properties of poly(styrene‐b‐butadiene)/clay nanocomposites
Authors: Liao Mingyi , Zhu Jiedong , Xu Hongde , Li Yang , Shan Wei 
Published: March 2004

AbstractStar‐shaped and linear block thermoplastic poly(styrene‐b‐butadiene) copolymer (SBS)/organophilic montmorillonite clays (OMMT) were prepared by a solution approach. The intercalation spacing in the nanocomposites and the degree of dispersion of nanocomposites were investigated by X‐ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The mechanical properties, dynamic mechanical properties, and thermal stability of these nanocomposites were determined. Results showed that SBS chains were well intercalated into the clay galleries and an intercalated nanocomposite was obtained. The mechanical strength of nanocomposites with the star‐shaped SBS/OMMT were significantly increased. The addition of OMMT also gave an increase of the elongation, the dynamic storage modulus, the dynamic loss modulus, and the thermal stability of nanocomposites. The increase of the elongation of nanocomposites indicates that SBS has retained good elasticity. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3430–3434, 2004
Organomodified montmorillonite as filler in natural and synthetic rubber
Authors: Bala P. , Samantaray B. K. , Srivastava S. K. , Nando G. B. 
Published: March 2004

AbstractThe filler action of dodecylamine (12C) intercalated montmorillonite (MNT) referred to as organomodified montmorillonite (12C‐MNT) up to 4 wt % on natural rubber (NR) and styrene butadiene rubber (SBR) was studied and findings were compared with respect to the unmodified Na‐MNT. X‐ray analysis was used to calculate the interchain separation (R and R′), degree of crystallinity (Xc), and distortion factor (k). It is noted that R and R′ showed the opposite trend, whereas Xc as well as k showed overall increasing trend with an increasing amount of 12C‐MNT on both NR and SBR. For Na‐MNT (1 wt %) filled NR and SBR, the corresponding magnitude of R and R ′ and Xc showed nearly no change, whereas kc increased significantly. The crosslinking density (vc) does not show any significant changes in NR, whereas for SBR, it increases with increasing 12C‐MNT as filler. Interestingly, in the case of 1 wt % pure Na‐MNT used as filler for both NR and SBR, vc was lower compared to the virgin rubbers. Both swelling index (si) and sol fraction (Q) do not show any significant variation for NR composites, whereas these decrease for SBR composites with increasing concentration of 12C‐MNT filler. On the contrary, NR and SBR with 1 wt % of Na‐MNT filler show greater magnitude of si and Q corresponding to the pure ones. Measurements of mechanical properties showed a significant increase in tensile strength and elongation at break for NR‐12C‐MNT (4 wt %) when compared with either virgin NR. In addition, modulus at the elongation at 100 and 200% in general increases with increasing loading of 12C‐MNT filler in NR. Similar observations were also noted in the case of SBR. Interestingly, when only pure Na‐MNT is used as filler, the strength of NR and SBR decreases drastically. Scanning electron microscopic studies were also to used support the mechanical behavior of NR‐12MNT and SBR‐12CMNT composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3583–3592, 2004
Thermal bonding of polypropylene nonwovens: Effect of bonding variables on the structure and properties of the fabrics
Authors: Bhat Gajanan S. , Jangala Praveen K. , Spruiell Joseph E. 
Published: March 2004

AbstractProperties of the point‐bonded nonwoven fabrics are dependent on the bonding conditions, in addition to those of the polymer/fiber. Thermally bonded carded webs were produced and characterized to investigate the role of bond area, bond size, and bonding temperature on the structure and properties of point‐bonded nonwoven fabrics. It was observed that the bond strength increases with bond area and bond size. The effects of bond area and bond size on fiber morphology were negligible. Significant morphological differences were observed in the bonded and the unbonded regions of the thermally bonded webs. To see how the staple fiber studies relate to the behavior of continuous filaments, similar sets of samples were produced and characterized by using the spunbond system. The observed trends for properties with respect to bonding conditions were similar for spunbond samples. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3593–3600, 2004
Short tandem repeats are associated with diverse mRNAs encoding membrane‐targeted proteins
Authors: Riley Donald E. , Krieger John N. 
Published: March 2004

AbstractWithin the genomes of multicellular organisms, short tandem repeating sequences (STRs) are ubiquitous, yet usage patterns remain obscure. The repeats (AC)n and (GU)n appear frequently in the untranslated regions (UTRs) of messenger RNAs (mRNAs). To investigate STR usage patterns, we used three approaches: (1) comparisons of individual mRNA database sequences including annotations and linked references, (2) statistical analysis of complete, UTR databases and (3) study of a large gene family, the aquaporins. Among 500 (AC)n‐ or (GU)n‐containing mRNAs, 58 (12%) had known functions. Of these, 50 (86%) encoded proteins whose activities involved membranes or lipids, including integral membrane proteins, peripheral membrane proteins, ion channels, lipid enzymes, receptors and secreted proteins. A control sequence (AU)n also occurred in mRNAs, but only 5% encoded membrane‐related functions. Investigation of all reported 3′ UTR sequences, demonstrated that the STR (AC)n was 9 times more common in mRNAs encoding membrane functions than in the total UTR database (P < 0.001). Similarly, (GU)n was 8 times more common in membrane‐function mRNAs than in the total database (P < 0.001). These observations suggest that (AC)n and (GU)n may be UTR signals for some mRNAs encoding membrane‐targeted proteins. This article contains supplementary material which may be viewed at the BioEssays website at http://www.interscience.wiley. com/jpages/0265‐9247/suppmat/index.html. BioEssays 26:434–444, 2004. © 2004 Wiley Periodicals, Inc.
Hedgehog: an unusual signal transducer
Authors: Bijlsma Maarten F. , Spek C. Arnold , Peppelenbosch Maikel P. 
Published: March 2004

AbstractHedgehog proteins are of pivotal importance for development and maintenance of tissue patterns in adult organisms. Despite the role of Hedgehogs in differentiation and tumorigenesis, signal transduction of Hedgehog remains a relatively uncharted area of signalling biochemistry. For proper Hedgehog distribution into tissues, two highly unusual covalent modifications are necessary, palmitoylation of a secreted protein and the attachment of a cholesterol group, making Hedgehog the only established sterolated protein in nature. Hedgehog exerts its function via two membrane‐bound receptors, Patched and Smoothened; presumably, Patched transports a cholesterol derivate out of cells which inhibits Smoothened. Binding of Hedgehog to Patched impedes this proposed pump function and thus Inhibition of Smoothened, which leads to expression of genetic Hedgehog targets via relief of transcriptional repression. These atypical features make Hedgehog physiology unique in biology and may explain why this field has attracted such significant attention. BioEssays 26:387–394, 2004. © 2004 Wiley Periodicals, Inc.
Anterior eye development and ocular mesenchyme: new insights from mouse models and human diseases
Authors: Cvekl Aleš , Tamm Ernst R. 
Published: March 2004

AbstractDuring development of the anterior eye segment, cells that originate from the surface epithelium or the neuroepithelium need to interact with mesenchymal cells, which predominantly originate from the neural crest. Failures of proper interaction result in a complex of developmental disorders such Peters' anomaly, Axenfeld–Rieger's syndrome or aniridia. Here we review the role of transcription factors that have been identified to be involved in the coordination of anterior eye development. Among these factors is PAX6, which is active in both epithelial and mesenchymal cells during ocular development, albeit at different doses and times. We propose that PAX6 is a key element that synchronizes the complex interaction of cell types of different origin, which are all needed for proper morphogenesis of the anterior eye. We discuss several molecular mechanisms that might explain the effects of haploinsufficiency of PAX6 and other transcription factors, and the broad variation of the resulting phenotypes. BioEssays 26:374–386, 2004. © 2004 Wiley Periodicals, Inc.
Plant hormones and homeoboxes: bridging the gap?
Authors: Hay Angela , Craft Judith , Tsiantis Miltos 
Published: March 2004

AbstractPlant hormones are signalling molecules that control growth and development. Growth of the aerial parts of higher plants requires the continuous activity of the shoot apical meristem, a small mound of cells at the apex of a plant. KNOTTED1‐like HOMEOBOX (KNOX) genes are involved in regulating meristem activity, however, little is known about how this regulation is mediated. Recent evidence suggests that KNOX transcription factors may control meristem development by regulating the balance of activities of multiple hormones. BioEssays 26:395–404, 2004. © 2004 Wiley Periodicals, Inc.
Under cover: causes, effects and implications of Hsp90‐mediated genetic capacitance
Authors: Sangster Todd A. , Lindquist Susan , Queitsch Christine 
Published: March 2004

AbstractThe environmentally responsive molecular chaperone Hsp90 assists the maturation of many key regulatory proteins. An unexpected consequence of this essential biochemical function is that genetic variation can accumulate in genomes and can remain phenotypically silent until Hsp90 function is challenged. Notably, this variation can be revealed by modest environmental change, establishing an environmentally responsive exposure mechanism. The existence of diverse cryptic polymorphisms with a plausible exposure mechanism in evolutionarily distant lineages has implications for the pace and nature of evolutionary change. Chaperone‐mediated storage and release of genetic variation is undoubtedly rooted in protein‐folding phenomena. As we discuss, proper protein folding crucially affects the trajectory from genotype to phenotype. Indeed, the impact of protein quality‐control mechanisms and other fundamental cellular processes on evolution has heretofore been overlooked. A true understanding of evolutionary processes will require an integration of current evolutionary paradigms with the many new insights accruing in protein science. BioEssays 26:348–362, 2004. © 2004 Wiley Periodicals, Inc.
The transcriptome: malariologists ride the wave
Authors: Wilson R.J.M.(Iain) 
Published: March 2004

AbstractThe Plasmodium falciparum genome‐sequencing project has provided malariologists with vast amounts of new information pertinent to a multitude of cellular processes that previously were only guessed about. In exploring this morass of predicted genes and proteins, there is now a danger of simply re‐inventing the cell. Fortunately, new global transcriptional analyses reassure malariologists that they are not dealing with just “any old cell.” The informative papers on the plasmodial transcriptome by Le Roch et al. (2003)1 and Bozdech et al. (2003)2 discussed below forge a bridge between the genomics and proteomics of P. falciparum. They are likely to act as a fulcrum upon which much future research will turn: for example, the study of regulation and feed‐back loops. BioEssays 26:339–342, 2004. © 2004 Wiley Periodicals, Inc.
Sexual conjugation in yeast: A paradigm to study G‐protein‐coupled receptor domain structure
Authors: Naider Fred , Estephan Racha , Englander Jacqueline , Suresh babu V. V. , Arevalo Enrique , Samples Karen , Becker Jeffrey M. 
Published: March 2004

AbstractThe yeast Saccharomyces cerevisiae undergoes cell fusion during sexual conjugation to form diploid cells. The haploids participating in this process signal each other through secreted peptide‐mating factors (α‐factor and a‐factor) that are recognized by G‐protein‐coupled receptors. The receptor (Ste2p) recognizing the tridecapeptide α‐factor is used as a model system in our laboratory to understand various aspects of peptide–receptor interactions and receptor structure. Using chemical procedures we have synthesized peptides corresponding to the seven transmembrane domains of Ste2p and studied their structures in membrane mimetic environments. Extension of these studies requires preparation of longer fragments of Ste2p. This article discusses strategies used in our laboratory to prepare peptides containing multiple domains of Ste2p. Data are presented on the use of chemical synthesis, biosynthesis, and native chemical ligation. Using biosynthetic approaches fusion proteins have been expressed that contain single receptor domains, two transmembrane domains connected by the contiguous loop, and the tail connected to the seventh transmembrane domain. Tens of milligrams of fusion protein were obtained per liter, and multimilligram quantities of the isotopically labeled target peptides were isolated using such biosynthetic approaches. Initial circular dichroism results on a chemically synthesized 64‐residue peptide containing a portion of the cytosolic tail and the complete seventh transmembrane domain showed that the tail portion and the hydrophobic core of this peptide maintained individual conformational preferences. Moreover, this peptide could be studied at near millimolar concentrations in the presence of micelles and did not aggregate under these conditions. Thus, these constructs can be investigated using high‐resolution nuclear magnetic resonance techniques, and the cytosolic tail of Ste2p can be used as a hydrophilic template to improve solubility of transmembrane peptides for structural analysis. © 2004 Wiley Periodicals, Inc. Biopolymers (Pept Sci), 2004
Peptide arrays with designed secondary structures for protein characterization using fluorescent fingerprint patterns
Authors: Usui Kenji , Ojima Tetsunori , Takahashi Mizuki , Nokihara Kiyoshi , Mihara Hisakazu 
Published: March 2004

AbstractTo realize a practical high‐throughput protein‐detection system, novel peptide arrays have been constructed using designed peptide libraries with loop, α‐helix, or β‐strand structures. Here, we describe the overview of the reported deigned peptide arrays with loop and α‐helix structures and the new results of those with β‐strand structures. Initially, several model peptides known to interact with model structured proteins were selected to establish the present strategy for high‐throughput detection of proteins. The fluorescent probes and suitable scaffolds of peptides were examined for the effective detection of proteins. The detection methods were established in solution and in an immobilized manner using the model systems. In the case of α‐helix peptide, the response of a peptide with fluorescent resonance energy transfer between two probes at both termini was several times higher than that of a peptide with a single probe. In the cases of peptides with other structures, however, proteins were effectively detectable even by the fluorescent change of one probe. Furthermore, structurally focused libraries consisting of a total of ca. 250 different peptides based on the model peptides with secondary and/or tertiary structures were constructed with systematic replacement of residues. Using these libraries, various proteins were characterized effectively to give their own fluorescent “protein fingerprint” patterns. The resulting protein fingerprints correlated with the recognition properties of the proteins. These studies demonstrate that arrays with peptide libraries based on designed structures can be promising tools for detecting the target proteins. Designed synthetic peptides play roles as the capturing agents to be developed for practical protein chips. © 2004 Wiley Periodicals, Inc. Biopolymers (Pept Sci), 2004
Epitope mapping and features of the epitope for monoclonal antibodies inhibiting enzymatic activity of Helicobacter pylori urease
Authors: Fujii Ryoji , Morihara Fumiko , Oku Takashi , Hifumi Emi , Uda Taizo 
Published: March 2004

AbstractTwo characteristic monoclonal antibodies (HpU‐2 and ‐18) out of 26 monoclonal antibodies (HpU‐1≈26) produced against Helicobacter pylori (H. pylori) urease showed a strong inhibitory effect against the enzymatic activity of the urease. Epitope mapping about some monoclonal antibodies of the HpU‐series inhibiting enzymatic activity was performed by using a surface plasmon resonance apparatus and by digesting H. pylori urease with trypsin, followed by mass spectroscopy. The sequences of the epitopes recognized by HpU‐2 and ‐18 were SVELIDIGGNRRIFGFNALVDR (22 mer) and IFGFNALVDR (10 mer), respectively. The former sequence is present as a part of a loop structure at a position close to the C‐terminal of the α‐subunit of H. pylori urease, although it has been suggested that the active site of the urease resides in the β‐subunit. The above peptide (22 mer) was chemically synthesized in a linear and cyclic form, and its conjugate with BSA was immunized in rabbits. The resultant serum induced by the linear form could specifically bind to H. pylori infecting human gastric mucosa. These results suggest that the above sequence (22 mer) must be an important epitope, although it locates in the α‐subunit but not in the β‐subunit. © 2004 Wiley Periodicals, Inc.
Treatment of MEK and toluene mixtures in biofilters: Effect of operating strategy an performance during transient loading
Authors: Atoche Jorge C. , Moe William M. 
Published: March 2004

AbstractIn recent years, biofiltration has been increasingly applied as an air pollution control technology to minimize or eliminate emissions of volatile organic compounds from industrial sources and environmental remediation activities. Although the ability of this technology to maintain high removal efficiency during relatively steady loading conditions has been well established for many waste streams, relatively little research has focused on development of operating strategies that could improve treatment performance during transient loading conditions typical of industrial operations. In the research described herein, two operating strategies were evaluated over a period of 295 days in biofilters treating a model waste gas stream containing a two‐component mixture of methyl ethyl ketone (MEK) and toluene. One biofilter was operated as a sequencing batch biofilter (SBB), and the other was operated as a conventional continuous‐flow biofilter (CFB). During “normal” steady loading conditions, the model waste stream contained MEK concentrations ranging from 80 to 89 ppmv and toluene concentrations ranging from 28 to 30 ppmv. Both biofilter operating strategies resulted in stable long‐term performance with greater than 99% contaminant removal during these normal loading conditions. On a regular basis, the influent MEK and toluene concentrations were temporarily increased to five times the normal influent concentration for the duration of 1 h to test performance during transient “shock loading” conditions. Biofilter performance during the model shock loading conditions demonstrate that SBB operating strategies can result in superior treatment in two important areas: (1) overall mass of contaminants removed and (2) minimum instantaneous removal efficiency. © 2004 Wiley Periodicals, Inc.
Quantifying anisotropic solute transport in protein crystals using 3‐D laser scanning confocal microscopy visualization
Authors: Cvetkovic A. , Straathof A. J. J. , Hanlon D. N. , van der Zwaag S. , Krishna R. , van der Wielen L. A. M. 
Published: March 2004

AbstractThe diffusion of a solute, fluorescein into lysozyme protein crystals has been studied by confocal laser scanning microscopy (CLSM). Confocal laser scanning microscopy makes it possible to non‐invasively obtain high‐resolution three‐dimensional (3‐D) images of spatial distribution of fluorescein in lysozyme crystals at various time steps. Confocal laser scanning microscopy gives the fluorescence intensity profiles across horizontal planes at several depths of the crystal representing the concentration profiles during diffusion into the crystal. These intensity profiles were fitted with an anisotropic model to determine the diffusivity tensor. Effective diffusion coefficients obtained range from 6.2 × 10−15 to 120 × 10−15 m2/s depending on the lysozyme crystal morphology. The diffusion process is found to be anisotropic, and the level of anisotropy depends on the crystal morphology. The packing of the protein molecules in the crystal seems to be the major factor that determines the anisotropy. © 2004 Wiley Periodicals, Inc.
Anwendungen der Magnetresonanz zur Untersuchung von Wasser‐, Temperatur‐ und Porenverteilung bei lebensmittelverfahrenstechnischen Prozessen
Authors: Regier M. , Knörzer K. , Badolato G. B. 
Published: March 2004

AbstractEs werden verschiedene Methoden der kernmagnetischen Resonanz (NMR) und ihrer Anwendung zur Bestimmung von Wasser‐, Temperaturverteilungen und Selbstdiffusionskoeffizienten im Verlauf von Prozessen im Bereich der Lebensmittelverfahrenstechnik vorgestellt. Ausgehend von den physikalischen Grundlagen der Magnetresonanz werden verschiedene Anwendungen gezeigt, die das Potenzial besitzen, zum tieferen Verständnis der verfahrenstechnischen Prozesse beizutragen: Beispielhaft wird die Bestimmung von Wasserverteilungen bei der Rehydratation von getrockneten Proben, die Ermittlung von Temperaturverteilungen bei der Mikrowellenerwärmung und von beobachtungszeitabhängigen Selbstdiffusionskoeffizienten bei der Mikrowellen‐Vakuumtrocknung gezeigt. Letztere können dazu genutzt werden, um weitere Aussagen über die innere Gewebestruktur wie Tortuosität und Porenradien zu erlangen.