bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gallium recovery from Bayer's liquor using hydroxamic acid resin
Authors: Selvi P. , Ramasami M. , Samuel M. H. P. , Sripriya R. , Senthilkumar K. , Adaikkalam P. , Srinivasan G. N. 
Published: February 2004

AbstractGallium, which is extensively used in the production of semiconductor materials, is present at the parts per million level in Bayer's liquor. The low concentration of gallium in the liquor, along with the high concentration of aluminum, prompted the use of chelating ion exchangers as an alternative separation process. A chelating ion exchange resin with hydroxamic groups attached to the copolymer of acrylonitrile‐divinylbenzene has been prepared by suspension polymerization followed by hydrolysis and chelation with hydroxylamine hydrochloride. Adsorption studies of gallium, using the above hydroxamic acid resin, were carried out. Adsorption was dependent on particle size of the resin and optimum conditions are determined for obtaining 0.3‐ to 0.5‐mm particles by varying the composition of the emulsion, using a secondary polymerization technique, and adding of diluents. Acrylic acid, as a diluent in the copolymer matrix, was found to increase the particle size and stability of the resin. IR studies, carried out for the products obtained at various stages, confirmed the conversion of polymer to resin with a hydroxamic acid group and its complex formation with gallium. Both batch and column studies were carried out for the determination of the capacity of the resin with synthetic Bayer's liquor containing gallium and commercial Bayer's liquor. Scaled‐up column studies were carried out with commercial Bayer's liquor to test the cyclability and stability of the resin. It was observed that chelated ion exchange resin could be recycled up to 30 times. The optimal liquid to solid phase ratio was found to be 1:12. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 847–855, 2004
Polymerization in a magnetic field. 14. Possibilities to improve field effect during methyl acrylate polymerization
Authors: Chiriac Aurica P. 
Published: February 2004

AbstractMagnetokinetic changes intervened in the radical polymerization of methyl acrylate in a continuous external magnetic field of 0.22 T was evidenced. The use of a matrix of polymerization, respectively, poly(ethylene glycol), was correlated with the obtained kinetic data. The occurring‐magnetokinetic changes were justified by the radical pair mechanism, Δg, which corresponds to the benzoyl peroxide decomposition into a magnetic field. The intervened magnetokinetic modifications during the reactions are correlated with the reaction conditions. The influence of the magnetic field is confirmed by the molecular weights of the obtained polymers, values interpreted from the viewpoint of the reaction conditions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1031–1036, 2004
DMC catalyzed epoxide polymerization: Induction period, kinetics, and mechanism
Authors: Wu Li‐Chuan , Yu Ai‐Fang , Zhang Min , Liu Bao‐Hua , Chen Li‐Ban 
Published: February 2004

AbstractThe kinetics of propylene oxide polymerization catalyzed by double metal cyanide complexes was studied by means of pressure measurements. The induction periods were determined as the time as the system pressure began to drop and the reaction rates were considered proportional to the slope of pressure decrease. The induction periods were found to depend on reaction temperature, water content, and the type and amount of catalysts, regulators, and solvents. Elevating reaction temperatures, using dried raw materials, and applying proper regulators favored shortened induction periods. The reaction rates were found to depend on the concentrations of catalyst C, monomer M, and regulator Tr as expressed in the equation

equation image

where K was a rate constant and k was a transition constant. The rates also depended on reaction temperature. The apparent activation energy was 59.1 kJ/mol according to the Arrhenius equation. A mechanism was proposed for the polymerization which was in good accordance with the experimental results. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1302–1309, 2004
Morphology and micromechanical deformation behavior of styrene–butadiene block copolymers. III. Binary blends of asymmetric star block copolymer with general‐purpose polystyrene
Authors: Adhikari R. , Michler G. H. , Goerlitz S. , Knoll K. 
Published: February 2004

AbstractThe correlation between morphology, mechanical properties, and micromechanical deformation behavior of the blends consisting of an asymmetric styrene/butadiene star block copolymer (ST2‐S74, total styrene volume content ΦPS= 0.74) and general‐purpose polystyrene (GPPS) was investigated using transmission electron microscopy and uniaxial tensile testing. Addition of 20 wt % of GPPS to the block copolymer resulted in a drastic reduction in strain at break, indicating the existence of critical PS lamella thicknessDc. AboveDclamellar block copolymers displayed a transition from ductile to brittle behavior, substantiating the mechanism of thin layer yielding proposed for lamellar star block copolymers. The blends showed a variety of deformation structures ranging from classical crazelike zones to those with internal shearlike components. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1208–1218, 2004
Visualization of poly(ether imide) and polycarbonate blending in an internal mixer
Authors: Lin Bin , Sundararaj Uttandaraman 
Published: February 2004

AbstractThe blending process of poly(ether imide)/polycarbonate (PEI/PC) was studied by visualization of blending in an internal mixer at 340°C. Distinct pellet deforming, softening, aggregation, stretching, bending, sheeting, and dispersing were seen during the blending process. By ramping the temperature of the barrel of the internal mixer, the process of pellet softening and deforming, and the phase‐inversion phenomenon were studied by examining the visualization results and the torque readings. It was found that a peak in torque occurred at the phase‐inversion point. It was also found that the blends are semitransparent at higher PEI composition (>80 wt %). SEM and TEM micrographs and DSC data verified the visualization result that PEI/PC blends are partially miscible at higher PEI compositions. The number‐average particle size was determined for the PEI/PC blends and it was found that the experimental results in the dilute solution limit for both PC drops and PEI drops did not match with the particle size predicted by Taylor's theory. The particle sizes at 15 wt % concentration were of the same order of magnitude as those calculated using Wu's correlation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1165–1175, 2004
Expression of hypoxia‐inducible, membrane‐bound carbonic anhydrase isozyme XII in mouse tissues
Authors: Halmi Piia , Lehtonen Jonna , Waheed Abdul , Sly William S. , Parkkila Seppo 
Published: February 2004

AbstractCarbonic anhydrase (CA) XII is a membrane‐associated enzyme that has been demonstrated to be normally expressed in some human tissues, to be upregulated in some cancers, and to be a hypoxia‐inducible gene product. In mouse, CA XII has been recently localized in the kidney. In the present study, we investigated CA XII gene and protein expression in other mouse tissues, with the kidney serving as a positive control for the reagents. The expression of CA XII mRNA was examined using polymerase chain reaction (PCR) amplification of commercial cDNAs produced from selected mouse tissues. A strong positive signal for CA XII mRNA was detected in the kidney, and weak signals were obtained in the testis and lung. Heart, spleen, liver, and skeletal muscle were negative. Immunohistochemical staining was performed using a mouse CA XII‐specific antibody and biotin‐streptavidin complex method. The results showed high expression of CA XII in the kidney, as expected. It was also highly expressed in the surface epithelial cells of the colon, whereas it was absent in the stomach, proximal small intestine, pancreas, liver, heart, and skeletal muscle. The maturing sperm cells showed a weak staining in a pattern that most probably indicates expression in the developing acrosomal membrane. The high expression in the kidney and colon suggests a role for CA XII in the maintenance of body ion and pH homeostasis in the mouse. However, the present findings demonstrated that CA XII has a very limited distribution in mouse tissues outside these two organs. Anat Rec Part A 277A:171–177, 2004. © 2004 Wiley‐Liss, Inc.
Chromaffin granules in the rat adrenal medulla release their secretory content in a particulate fashion
Authors: Crivellato Enrico , Belloni Anna , Nico Beatrice , Nussdorfer Gastone G. , Ribatti Domenico 
Published: February 2004

AbstractExocytosis is considered the main route of granule discharge in chromaffin cells. We recently provided ultrastructural evidence suggesting that piecemeal degranulation (PMD) occurs in mouse adrenal chromaffin cells. In the present study, we processed rat adrenal glands for transmission electron microscopy (TEM), and examined chromaffin cells for changes characteristic of PMD. Both adrenaline (A)‐ and noradrenaline (NA)‐storing cells express ultrastructural features suggestive of a slow and particulate mode of granule discharge. In adrenaline‐containing cells, some granules present enlarged dimensions accompanied by eroded or dissolved matrices. Likewise, a number of granules in NA‐releasing cells show content reduction with variably expanded granule chambers. Dilated, empty granule containers are recognizable in the cytoplasm of both cell types. Characteristically, altered granules and empty containers are seen intermingled with normal, resting granules. In addition, chromaffin granules often show irregular profiles, with budding or tail‐like projections of their limiting membranes. Thirty 150‐nm‐diameter membrane‐bound vesicles with a moderately electron‐dense or ‐lucent internal structure are observable in the cytoplasm of both cell types. These vesicles are seen among the granules and some of them are fused with the perigranule membranes in the process of attachment to or budding from the granules. These data add further support to the concept that PMD may be an alternative secretory pathway in adrenal chromaffin cells. Anat Rec Part A 277A:204–208, 2004. © 2004 Wiley‐Liss, Inc.
The dorsal lingual epithelium of Rhinoclemmys pulcherrima incisa (Chelonia, Cryptodira)
Authors: Josef Beisser Christian , Lemell Patrick , Weisgram Josef 
Published: February 2004

AbstractThis study employed light microscopic (LM), scanning electron microscopic (SEM), and transmission electron microscopic (TEM) methods to provide detailed morphological information on the histological and ultrastructural features of the dorsal tongue epithelium of Rhinoclemmys pulcherrima incisa. SEM revealed columnar papillae laterally, as well as papillae, which tend to have a ridge‐like appearance in the center of the tongue. LM and TEM showed three different zones of lingual epithelium: a stratified apical area with serous cells at the top of the papillae, a stratified lateral area with both serous and mucus cells, and an unstratified glandular area consisting of distinct glandular ducts with mucus cells. Comparison with morphological data from other turtles shows that the lingual epithelial structure in R. p. incisa is in accordance with that observed for other generalized omnivores which prefer a terrestrial lifestyle, thus matching the ecological information about this species. Anat Rec Part A 277A:227–235, 2004. © 2004 Wiley‐Liss, Inc.
Postnatal growth of cardiomyocytes in the left ventricle of the rat
Authors: Wulfsohn D. , Nyengaard J.R. , Tang Y. 
Published: February 2004

AbstractWe studied the development of myocytes and interstitium using perfusion‐fixed left ventricles obtained from normal female Wistar rats at 5 days (n = 5), 25 days (n = 5), and 125 days (n = 5) of age. Using design‐based stereological methods and light microscopy, we estimated the following parameters: volume of left ventricle made up by myocytes, myocyte nuclei, and interstitium; total numbers of myocyte and non‐myocyte nuclei; mean volumes of myocyte nuclei; the total volume, surface area, and length of fibers; and the mean star volumes of fibers. Some derived parameters were also calculated, namely, the mean myocardium volume per nucleus and the mean fiber cross‐sectional area. We found that postnatal myocyte growth after day 5 in the young rat is largely hypertrophic, while interstitial growth is hyperplastic. The increase in left ventricular mass was 10‐fold over the ages studied, whereas total length, surface area, and volume of fibers increased approximately 3‐, 8‐, and 11‐fold over the period. Relative rates of growth implied that fiber growth was dominated by an increase in length compared to other dimensions. The total number of myocyte nuclei (∼30 × 106) did not change between 5 and 25 days of age, but then almost doubled in 125‐day‐old rats. The number of non‐myocyte nuclei increased 9‐fold over the period studied in an exponential manner. The mean myocyte nucleus volume tripled between the ages of 5 and 25 days and then remained the same. The volume‐weighted mean nucleus volume was highly variable and showed no significant trend with age. Our results provide support for the claim made by some researchers that myocyte proliferation had ceased by day 5 after birth, but do not provide evidence for binucleation of myocytes between 5 and 25 days after birth. Reported numbers of myocyte nuclei express a net growth and do not rule out both myocyte death and creation throughout the early postnatal period. We clearly detect an increase in the number of myocyte nuclei from 25 to 125 days but are not able to state whether this increase reflects myocyte proliferation or myocyte binucleation. To determine this would require special double‐staining techniques to delineate intercalated discs and myocyte membranes. Our results agree very well with the limited data available from other studies that have used unbiased stereology. It is important to use unbiased designs that consider anisotropy as well as heterogeneity of the heart in sampling schemes, and to determine absolute quantities to avoid problems associated with interpreting changes in density (the “reference trap”). Anat Rec Part A 277A:236–247, 2004. © 2004 Wiley‐Liss, Inc.
Insect digestion: Potential applications in insect management
Authors: Oppert Brenda , Johnson Kelly 
Published: February 2004

AbstractThe papers assembled in this special issue were originally presented by researchers gathered at an informal symposium entitled “Insect Digestion: Potential Applications in Insect Management” at the National Meeting of the Entomological Society of America in Fort Lauderdale, Florida in November 2002. Although symposium participants and attendees clearly came from a diversity of backgrounds, they shared a common goal: to bring together their collective knowledge of insect digestive physiology and promote discussions of control methods that target insect digestion. The manuscripts published in this issue reflect the breadth of that knowledge. They include a structural and functional study of a peptide hormone that modulates digestion in mosquitoes, investigation of responses of Colorado potato beetle to transgenically expressed proteinase inhibitors, demonstration of the importance of phosphorous as a nutritive element of caterpillars, and phylogenetic analysis of insect trypsins and inhibitor resistance. The papers reinforce the notion that approaches to the study of insect digestion are as diverse as the insects we study, and it is our hope that this endeavor will promote new ideas for effective pest management tools.The organizers would like to thank the Entomological Society of America for hosting the informal symposium, and to all who presented and attended. We are especially grateful to the Executive Editor of Archives of Insect Biochemistry and Physiology, David Stanley, and his editorial staff for making publication of this special issue possible.
Biochemical and cytoimmunological evidence for the control of Aedes aegypti larval trypsin with Aea‐TMOF
Authors: Borovsky Dov , Meola Shirlee M. 
Published: February 2004

AbstractTrypsin and chymotrypsin‐like enzymes were detected in the gut of Aedes aegypti in the four larval instar and pupal developmental stages. Although overall the amount of trypsin synthesized in the larval gut was 2‐fold higher than chymotrypsin, both enzymes are important in food digestion. Feeding Aea‐Trypsin Modulating Oostatic Factor (TMOF) to Ae. aegypti and Culex quinquefasciatus larvae inhibited trypsin biosynthesis in the larval gut, stunted larval growth and development, and caused mortality. Aea‐TMOF induced mortality in Ae. aegypti, Cx. quinquefasciatus, Culex nigripalpus, Anopheles quadrimaculatus, and Aedes taeniorhynchus larvae, indicating that many mosquito species have a TMOF‐like hormone. The differences in potency of TMOF on different mosquito species suggest that analogues in other species are similar but may differ in amino acid sequence or are transported differently through the gut. Feeding of 29 different Aea‐TMOF analogues to mosquito larvae indicated that full biological activity of the hormone is achieved with the tetrapeptide YDPA. Using cytoimmunochemical analysis, intrinsic TMOF was localized to ganglia of the central nervous system in larvae and male and female Ae. aegypti adults. The subesophageal, thoracic, and abdominal ganglia of both larval and adult mosquitoes contained immunoreactive cells. Immunoreactive cells were absent in the corpus cardiacum of newly molted 4th instar larvae but were found in late 4th instar larvae. In both males and females, the intrinsic neurosecretory cells of the corpus cardiacum were filled with densely stained immunoreactive material. These results indicate that TMOF‐immunoreactive material is synthesized in sugar‐fed male and female adults and larvae by the central nervous system cells. Arch. Insect Biochem. Physiol. 55:124–139, 2004. © 2004 Wiley‐Liss, Inc.
Dietary phosphorus affects the growth of larval Manduca sexta
Authors: Perkins Marc C. , Woods H. Arthur , Harrison Jon F. , Elser James J. 
Published: February 2004

AbstractAlthough phosphorus has long been considered an important factor in the growth of diverse biota such as bacteria, algae, and zooplankton, insect nutrition has classically focused on dietary protein and energy content. However, research in elemental stoichiometry has suggested that primary producer biomass has similar N:P ratios in aquatic and terrestrial systems, and phosphorus‐rich herbivores in freshwater systems frequently face phosphorus‐limited nutritional conditions. Therefore, herbivorous insects should also be prone to phosphorus limitation. We tested this prediction by rearing Manduca sexta larvae on artificial and natural (Datura wrightii leaves) diets containing varying levels of phosphorus (approximately 0.20, 0.55, or 1.2% phosphorus by dry weight). For both artificial and natural diets, increased dietary phosphorus significantly increased growth rates and body phosphorus contents, and shortened the time to the final instar molt. Caterpillars did not consistently exhibit compensatory feeding for phosphorus on either type of diet. The growth and body phosphorus responses were not explicable by changes in amounts of potassium or calcium, which co‐varied with phosphorus in the diets. Concentrations of phosphorus in D. wrightii leaves collected in the field varied over a range in which leaf phosphorus is predicted to affect M. sexta's growth rates. These results suggest that natural variation in dietary phosphorus is likely to affect the growth rate and population dynamics of M. sexta, and perhaps larval insects more generally. Arch. Insect Biochem. Physiol. 55:153–168, 2004. © 2004 Wiley‐Liss, Inc.
Coevolution of insect trypsins and inhibitors
Authors: Lopes A.R. , Juliano M.A. , Juliano L. , Terra W.R. 
Published: February 2004

AbstractMany plant proteinase inhibitors have lysine at the P1 position, presumably to avoid hydrolysis by insect trypsins. Lepidopteran trypsins appear to have adapted to resist proteinase inhibitors through increased inhibitor hydrolysis and decreased binding to inhibitor hydrophilic reactive sites. Lepidopteran digestive trypsins prefer lysine at the P1 position and have substrate binding subsites more hydrophobic than trypsins from insects in other orders. All available sequences of sensitive and inhibitor‐insensitive insect trypsins were aligned with porcine trypsin, for which interactions with Kunitz and Bowman‐Birk inhibitor are known. After discounting conserved positions and positions not typical of sensitive or insensitive trypsins, the following residues were considered important to insect trypsin‐PI interactions (chymotrypsin numbering): 60, 94, 97, 98, 99, 188, 190, 213, 215, 217, 219, 228. These residues support the Neighbor Joining analysis tree branches separating sensitive and insensitive trypsin sequences. Primary sequences interacting with PIs are around the active site, with some forming part of the S1 (188, 217, 219 and 228) or S4 (99, 215) pockets. Arch. Insect Biochem. Physiol. 55:140–152, 2004. © 2004 Wiley‐Liss, Inc.
Colorado potato beetles compensate for tomato cathepsin D inhibitor expressed in transgenic potato
Authors: Brunelle France , Cloutier Conrad , Michaud Dominique 
Published: February 2004

AbstractWe reported earlier the importance of digestive cathepsin D‐like activity for initiating dietary protein hydrolysis in Colorado potato beetle, Leptinotarsa decemlineata Say [Brunelle et al. (1999) Arch. Insect Biochem. Physiol. 42:88–98]. We assessed here whether transgenic lines of potato (Solanum tuberosum L.) expressing a cathepsin D inhibitor (CDI) from tomato would show resistance to the beetle, or if the insect would compensate for the loss of cathepsin D activity after ingesting the recombinant inhibitor. Transgenic potato lines expressing tomato CDI were developed by Agrobacterium tumefaciens genetic transformation, and selected based on their relative amount of CDI. After confirming the absence of detectable visible effects of CDI on the plant's phenotype, diet assays with control and transgenic lines were carried out to assess the impact of the inhibitor on growth and development of the insect. Leaf consumption, relative growth rate, molting incidence, and digestive protease activity were monitored at 12‐h intervals over 132 h for 3rd‐instar larvae provided with transgenic potato foliage. Leaf consumption and relative growth rate were slightly reduced during the first 12 h for larvae fed CDI, but no significant differences were observed thereafter. In contrast, time for molting to the 4th larval stage was significantly longer for larvae fed modified plants, with developmental delays of ˜10 h (0.5 day) compared to control larvae. Recombinant CDI also had an impact on the insect's digestive physiology, readily inducing overproduction of digestive proteases (rubiscases), followed by a gradual decrease of total and pepstatin‐sensitive activity. Overall, these observations show the ability of Colorado potato beetle to compensate for the loss of cathepsin D activity by modulating its digestive protease complement in response to aspartate‐type inhibitors in the diet. From a practical viewpoint, these data stress the importance of devising improved strategies for the effective inhibition of insect digestive proteinases in vivo, based on the use of hybrid inhibitors active against different protease classes. Arch. Insect Biochem. Physiol. 55:103–113, 2004. © 2004 Wiley‐Liss, Inc.