bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure and control release of chitosan/carboxymethyl cellulose microcapsules
Authors: Zhang Lina , Jin Yong , Liu Haiqing , Du Yuming 
Published: September 2002

AbstractMicrocapsules of chitosan/sodium carboxymethyl cellulose (NaCMC) were successfully prepared using a novel method of emulation phase separation. Their structure and morphology were characterized by infrared spectroscopy (IR), scanning electron microscopy (SEM), and X‐ray diffraction. Bovine serum albumin (BSA) was encapsulated in the microcapsules to test their release behavior. The swelling behavior, encapsulation efficiency, and release behavior of the microcapsules with different chitosan contents and pH conditions were investigated. The results indicated that the microcapsules have a high encapsulation efficiency (75%) and a suitable size (20–50 μm). The BSA in the microcapsules was speedily released at pH 7.2, namely, in intestinal fluid. The BSA release was reduced with increase of the chitosan content from 17 to 38% in the microcapsules. Acid‐treated microcapsules have a compact structure, owing to a strong electrostatic interaction caused by —NH2 groups of chitosan and —COOH groups of CMC, and the encapsulated BSA was hardly released at pH 1.0, namely, in gastric juice. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 584–592, 2001
Polymer‐bound ethylenediamine–borane reagent: A new class of polymeric reducing agent
Authors: Rajasree K. , Devaky K. S. 
Published: September 2002

AbstractA polymer‐supported ethylenediamine (EDA)–borane reagent was prepared under mild reaction conditions. The reagent was found to be efficient and selective in the reduction of aldehydes to the corresponding alcohols in high yields at room temperature. The polymeric reagent was prepared on a Merrifield resin and on a 1,6‐hexanediol diacrylate‐crosslinked polystyrene resin (HDODA–PS). HDODA–PS was prepared by suspension polymerization and chloromethylated by a Friedel–Crafts reaction. The preparation of the polymer‐bound EDA–borane reagent involves a series of polymer analogous reactions, such as amination of the chloromethyl resin, conversion to amine hydrochloride, and, finally, complexation with sodium borohydride. The reagent exhibited good chemoselectivity in the reduction of aldehydes. The reduction reactions were carried out with a 2 molar excess of the polymeric reagent. In the competitive reduction of a 1:1 molar mixture of benzaldehyde and acetophenone, benzaldehyde was selectively reduced to benzyl alcohol. The spent resin could be recycled by treating with sodium borohydride. The recycled resin was used several times without much loss in chemical reactivity and mechanical stability. The HDODA–PS resin was found to be more efficient than was the Merrifield resin in the preparation of the reagent as well as in the reduction reactions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 593–600, 2001
Complexation between poly(methacrylic acid) and poly(vinylpyrrolidone)
Authors: Liu Shouxin , Fang Yu , Hu Daodao , Gao Gailing , Ma Jianbiao 
Published: September 2002

AbstractThe complexation between poly(methacrylic acid) (PMAA) and poly(vinylpyrrolidone) (PVP) in aqueous phase was studied by various fluorescence techniques, including fluorescence anisotropy measurements, fluorescence probe studies, and nonradiation energy transfer. It was demonstrated that the complexation of PMAA with PVP occurs within a pH range of 1 to 5 and along with complexation, the conformation of PMAA changed from a hypercoiled to a loosely coiled form. The complex ratio between the two polymers is 2:1 (PMAA/PVP, in monomer unit). Salt effect studies showed that the complexation occurred due to formation of hydrogen bonds between the two polymers. Based on these conclusions and the “connected cluster model” for PMAA at low pH, a “ladder with connected cluster” model was proposed for the structure of PMAA/PVP complex formed at low pH. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 620–627, 2001
Development of a methodology for characterizing commercial chlorinated latex gloves
Authors: Sen Sumit , Mabuni Clayton , Walsh Donna 
Published: September 2002

AbstractChlorination of gloves has gained popularity as a more permanent method of reducing the inherent tackiness of natural rubber latex compared to using powder as a dusting lubricant. Transmission of proteins in natural rubber latex into the air as a result of using powder on natural rubber latex gloves may cause serious complications to allergic individuals. A methodology for characterizing commercial chlorinated natural rubber latex gloves using a combination of attenuated total reflectance (ATR)–Fourier transform infrared (FTIR) spectroscopy and ion chromatography (IC) is described. ATR–FTIR studies established that 930–915 and 670–650 cm−1 are definitive wavenumber ranges for the identification of chlorine in commercial chlorinated latex gloves. Confirmation of the ATR–FTIR results and semiquantification of the chlorine content in the latex gloves was carried out by the IC technique. This methodology can be used by glove manufacturers to determine the amount of chlorine in batches of commercial gloves, and thereby prevent possible threats to public health arising from the deterioration of surgical and examination chlorinated latex gloves under severe storage conditions before the end of their expected shelf life. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 672–682, 2001
Development and application of triglyceride‐based polymers and composites
Authors: Khot Shrikant N. , Lascala John J. , Can Erde , Morye Shantaram S. , Williams George I. , Palmese Giuseppe R. , Kusefoglu Selim H. , Wool Richard P. 
Published: September 2002

AbstractTriglyceride oils derived from plants have been used to synthesize several different monomers for use in structural applications. These monomers have been found to form polymers with a wide range of physical properties. They exhibit tensile moduli in the 1–2 GPa range and glass transition temperatures in the range 70–120 °C, depending on the particular monomer and the resin composition. Composite materials were manufactured utilizing these resins and produced a variety of durable and strong materials. At low glass fiber content (35 wt %), composites produced from acrylated epoxidized soybean oil by resin transfer molding displayed a tensile modulus of 5.2 GPa, a flexural modulus of 9 GPa, a tensile strength of 129 MPa, and flexural strength of 206 MPa. At higher fiber contents (50 wt %) composites produced from acrylated epoxidized soybean oil displayed tensile and compression moduli of 24.8 GPa each, and tensile and compressive strengths of 463.2 and 302.6 MPa, respectively. In addition to glass fibers, natural fibers such as flax and hemp were used. Hemp composites of 20% fiber content displayed a tensile strength of 35 MPa and a tensile modulus of 4.4 GPa. The flexural modulus was ∼2.6 GPa and the flexural strength was in the range 35.7–51.3 MPa, depending on the test conditions. The flax composite materials had tensile and flexural strengths in the ranges 20–30 and 45–65 MPa, respectively. The properties exhibited by both the natural‐ and synthetic fiber‐reinforced composites can be combined through the production of “hybrid” composites. These materials combine the low cost of natural fibers with the high performance of synthetic fibers. Their properties lie between those displayed by the all‐glass and all‐natural composites. Characterization of the polymer properties also presents opportunities for improvement through genetic engineering technology. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 703–723, 2001
Water diffusion studies in polyimide thin films
Authors: Seo Jongchul , Han Haksoo 
Published: September 2002

AbstractThe water diffusion behaviors and activation energies of PDA‐ and ODA‐based polyimide thin films were quite dependent on both the chemical structure and the morphological structure in the films. The water diffusion coefficients of polyimide thin films increased with increasing temperature. The activation energies varied in the range of 5.81 to 9.27 kcal/mol and were relatively higher for the PDA‐based polyimide thin films than for the corresponding ODA‐based polyimide thin films. For the PDA‐ and ODA‐based polyimide films, the differences in the morphological structures and the chemical affinity to water molecules might be reflected directly on the water diffusion behaviors. The PDA‐based polyimide films exhibited a relatively more ordered morphological structure (high crystallinity and good in‐plane orientation) than that of the corresponding ODA‐based polyimide thin films, which may serve as impenetrable obstacles for the water diffusion in the out‐of‐plane direction. Consequently, it may lead to a relatively slower water diffusion and high activation energy in the PDA‐based polyimide thin films. Additionally, the PDA‐based polyimide films with relatively lower chemical affinity showed relatively low diffusion coefficients and high activation energies. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 731–737, 2001
Dissolution and characterization of regenerated Antheraea pernyi silk fibroin
Authors: Kweon Haeyong , Park Young Hwan 
Published: September 2002

AbstractDissolution of Antheraea pernyi silk fiber was carried out in a calcium nitrate solution with various dissolving conditions. The solubility was significantly dependent on the concentration of calcium nitrate, dissolving temperature, and time. The proper conditions of dissolution were found as 7M calcium nitrate, 100°C temperature, and 3 h dissolving time. The aqueous solution of A. pernyi silk fibroin was composed of a mixture of polypeptides with several molecular weights above 14 kDa. FTIR and XRD showed that regenerated A. pernyi silk fibroin was composed of an α‐helix as well as a random‐coil conformation while silk fiber had a traditional β‐sheet structure. The endo–exo transition in the temperature ranges of 228–232°C also supports these conformations of regenerated silk fibroin film. TGA and DTG curves showed that the thermal decomposition of regenerated A. pernyi silk fibroin proceeded by three steps, not dependent on the conformation. The mechanical damping peaks (tan δ) appeared about 227°C with a minor shoulder maximum about 240°C, which were somewhat lower than those of tussah silk fiber. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 750–758, 2001
Novel formulations of high‐performance epoxy–amine networks based on the use of nanoscale phase‐separated antiplasticizers
Authors: Sauvant Valérie , Halary Jean Louis 
Published: September 2002

AbstractThe addition of an antiplasticizing agent in epoxy–amine resin formulations was revisited. The choice, as the antiplasticizer, of a chemical species which is fully miscible with the mixture of monomers but gives rise to nanoscale phase separation along the network construction was shown to be greatly favorable. Small domains, enriched in additive molecules, segregate in the polymer matrix, which is itself plasticized by residual additive molecules. Use of the additives did not change markedly the cure cycle and the total extent of reaction after full cure. The main effects of this special morphology on network properties were the depression of the glass transition temperature, Tg, of the matrix and the appearance of some damping (so‐called μ‐relaxation) in the temperature range intermediate between the secondary relaxation and the main mechanical relaxation. Networks prepared in this way were shown (1) to save a sufficiently high value of Tg in the view of the applications, (2) to present a higher modulus and higher toughness around room temperature than those of the conventional systems without an additive, and (3) to exhibit a lower water uptake at equilibrium than that of their regular homolog. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 759–774, 2001
Energetic studies on epoxy–polyurethane interpenetrating polymer networks
Authors: Park Soo‐Jin , Jin Joong‐Seong 
Published: September 2002

AbstractA blend system prepared from epoxy resin (EP) and polyurethane (PU) was investigated in terms of glass‐transition temperature (Tg), contact angle, mechanical interfacial, and mechanical properties. Deionized water and diiodomethane were chosen as the angle testing liquids. In this work, the models of Owens–Wendt and Wu, using a geometric mean, were studied to analyze the surface free energy of the EP/PU blend system. Fourier transform infrared (FTIR) spectroscopy was employed to investigate the intermolecular hydrogen bonding and functional group changes. The impact test was carried out at room and cryogenic temperatures to determine the low‐temperature performance of PU. As a result, mechanical interfacial and mechanical properties give a maximum value at 40 phr of PU, and the deviation of Tg of EP/PU was the closest at 40 phr of PU. Thus it is concluded that EP and PU have the best compatibilities at this ratio. Furthermore, the specific (or polar) component of the surface free energy of the blend system was largely influenced on the addition of the PU, resulting in increasing the critical stress intensity factor (KIC) and the impact strength for the excellent low‐temperature performance. These results could be explained by means of improvement of hydrogen bonding between the hydroxyl group in EP and isocyanate group in PU. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 775–780, 2001
Pulmonary appendix of the short‐tailed shrew (Blarina): A unique immunologic organ
Authors: Parke Wesley Wilkin 
Published: September 2002

AbstractThe right bronchus of the short‐tailed shrew, Blarina brevicauda, terminates in a nonrespiratory pulmonary appendix (PA) containing two bronchial extensions. The experimentally demonstrated ability of these structures to collect and peristaltically expel aspirated material was initially assumed to be a sufficient reason for their developmental persistance, but as bronchus associated lymphoid tissue (BALT) became a subject of immunologic interest in other species, a possible immunologic role for the concentrations of BALT observed in the shrew PA were investigated. As the BALT of the PA contained many well‐differentiated plasma cells and numerous particle‐containing macrophages, 6‐μ paraffin sections were treated with an immunoperoxidase avidin‐biotin preparation that chromogenically identified alpha chains of IgA in many of the PA plasma cells and their associated luminal secretions. Also, vascular injections revealed that the PA had a complex relationship with anastomotic sinusoids connecting the bronchial and pulmonary circulation systems, and scanning electron microscopy showed that the luminal epithelial surfaces of the PA were virtually identical to the scattered BALT aggregates in the bronchi of other animals. It thus appeared that these unique structures in the shrew are morphologically and topographically suited to receive aspirated antigens that induce secretory IgA production, while possibly providing other humoral and cellular immunologic products to the general circulation. Anat Rec 266:184–191, 2002. © 2002 Wiley‐Liss, Inc.
Proliferation and apoptosis in the developing human neocortex
Authors: Chan Wood Yee , Lorke Dietrich E. , Tiu Sau Cheung , Yew David T. 
Published: September 2002

AbstractThe cell kinetics of the developing central nervous system (CNS) is determined by both proliferation and apoptosis. In the human neocortex at week 6 of gestation, proliferation is confined to the ventricular zone, where mitotic figures and nuclear immunoreactivity for proliferating cell nuclear antigen (PCNA) are detectable. Cell division is symmetric, with both daughter cells reentering mitosis. At week 7, the subventricular zone, a secondary proliferative zone, appears. It mainly gives rise to local circuit neurons and glial cells. Around week 12, the ventricular and subventricular zones are thickest, and the nuclear PCNA label is strongest, indicating that proliferation peaks at this stage. Thereafter, asymmetric division becomes the predominant mode of proliferation, with one daughter cell reentering mitosis and the other one migrating out. Towards late gestation, the ventricular and subventricular zones almost completely disappear and proliferation shifts towards the intermediate and subplate zones, where mainly glial cells are generated. A remnant of the subventricular zone with proliferative activity persists into adulthood. In general, proliferation follows a latero‐medial gradient in the neocortex lasting longer in its lateral parts. Apoptotic nuclei have been detected around week 5, occurring in low numbers in the ventricular zone at this stage. Apoptotic cell death increases around midgestation and then spreads throughout all cortical layers, with most dying cells located in the ventricular and subventricular zones. This spatial distribution of apoptosis extends into late gestation. During the early postnatal period, most apoptotic cells are still located in the subcortical layers. During early embryonic development, proliferation and apoptosis are closely related, and are probably regulated by common regulators. In the late fetal and early postnatal periods, when proliferation has considerably declined in all cortical layers, apoptosis may occur in neurons whose sprouting axons do not find their targets. Anat Rec 267:261–276, 2002. © 2002 Wiley‐Liss, Inc.
Midline corpus callosum is a neuroanatomical focus of fetal alcohol damage
Authors: Bookstein Fred L. , Sampson Paul D. , Connor Paul D. , Streissguth Ann P. 
Published: September 2002

AbstractPrenatal exposure to high levels of alcohol often induces birth defects that combine morphological stigmata with neurological or neuropsychological deficits. But it has proved problematic to diagnose these syndromes in adolescents and adults, in whom the morphological signs are absent or attenuated, the behavioral deficits nonspecific, and the exposure history often difficult to reconstruct. Localizing the associated brain abnormalities might circumvent most of these difficulties. To this end, three‐dimensional (3D) locations were recorded for 67 homologous points on or near the corpus callosum in magnetic resonance (MR) brain images from 60 adolescents and adults who were normal, 60 diagnosed with fetal alcohol syndrome, and 60 diagnosed with fetal alcohol effects. We combined the standard statistical approach to this type of geometric data, Procrustes analysis, with a multivariate strategy focusing on differences in variability. In this data set, the shape of the corpus callosum and its vicinity proves systematically much more variable in the alcohol‐affected brains than in those of the normal subjects. From this excess variability follows a promising classification rule, having both high sensitivity (100 out of 117) and high specificity (49 out of 60) in this sample. The discrimination uses four landmark points and two summary scores of callosal outline shape. The information from the corpus callosum and vicinity, as viewed in MR brain images of full‐grown subjects, may serve as a permanent record of the prenatal effects of alcohol, even in patients who are first suspected of these syndromes relatively late in life or who lack the facial signs of prenatal alcohol damage. The statistical pattern underlying the callosal diagnosis also leads to speculations on mechanisms of the prenatal damage. Anat Rec (New Anat) 269:162–174, 2002. © 2002 Wiley‐Liss, Inc.
A closer look at Neanderthal postcanine dental morphology: The mandibular dentition
Authors: Bailey Shara E. 
Published: September 2002

AbstractNeanderthals are known to exhibit unique incisor morphology as well as enlarged pulp chambers in postcanine teeth (taurodontism). Recent studies suggest that their overall dental pattern (i.e., in morphologic trait frequencies) is also unique. However, what this means in a phylogenetic sense is not known. Although exploring the polarity of dental morphologic characters is essential to understanding the phylogenetic implications of unique patterns of variation, few have undertaken this task. This study moves beyond standard scoring methods, which are based on modern humans, to include several postcanine traits that have not been considered previously. In addition, Homo erectus is used as an outgroup to Neanderthals and modern humans to explore the polarity of these traits. The findings of this study suggest that Neanderthals are not only unique in their pattern of dental trait frequencies (as found in previous studies) but that they present several dental autapomorphies, as well. These include a high frequency of the mid‐trigonid crest in lower molars and unique morphology of the lower premolars. Interestingly, these characters are not observed in the Mauer mandible, which some have claimed to be a member of a chronospecies that is a unique ancestor to Neanderthals. Anat Rec (New Anat) 269:148–156, 2002. © 2002 Wiley‐Liss, Inc.
Rapid technique for imaging the blood vascular system using stereoangiography
Authors: Sedlmayr Jayc C. , Witmer Lawrence M. 
Published: September 2002

AbstractData on vascular anatomy traditionally have been derived from time‐consuming gross dissection and histology, which has prevented the assembly of large sample sizes. Vascular injection of radiopaque medium (angiography) is a rapid technique, but, as typically performed, it has limitations (e.g., superimposition and poor subsequent dissectibility). We present a novel angiographic technique comprised of two elements: 1) a new, dissectible injection medium; and (2) stereoradiography. The injection medium consists of liquid barium (providing radiopacity) and latex (providing dissectibility). Domestic duck heads were the study system. The relative concentrations of barium and latex were varied, and the resulting radiographs were assayed for vessel radiopacity and the number of observable vessels. A wide range of barium percentages yielded excellent results, suggesting that preparation of the medium can be “eyeballed” for most applications, which enhances processing speed. The stereoradiographic element solved the superimposition problem, allowing stunning resolution of the spatial relationships of vessels to each other and to other tissues. Stereoangiography is a fast and easy technique that permits the acquisition of detailed anatomical data from many specimens, thereby enabling something rarely achieved: population‐level anatomical studies. Anat Rec 267:330–336, 2002. © 2002 Wiley‐Liss, Inc.
Mapping the roots of agriculture in southern Arabia: the application of satellite remote sensing, global positioning system and geographic information system technologies
Authors: Harrower M. , McCorriston J. , Oches E. A. 
Published: September 2002

AbstractSatellite remote sensing, global positioning system (GPS) and geographical information system (GIS) technologies form a powerful methodological and analytical triad for archaeological research, particularly in remote regions where few large‐scale maps are available. This paper outlines the application of these technologies as a component of the Roots of Agriculture in Southern Arabia (RASA) research project and provides a review for archaeologists interested in potential applications, particularly in arid and semi‐arid environments. We used LANDSAT satellite imagery and GPS data to construct a GIS and provide a foundation for the management and analysis of archaeological, geomorphological and palaeoecological evidence of middle Holocene environmental conditions and human land‐use in the remote highlands of southern Yemen. Using both supervized and unsupervized multispectral landscape classification procedures we categorized the landscape into seven classes based on landform and sedimentary cover characteristics. The resulting GIS helps us evaluate the relationship between landscape characteristics, site location, site preservation, and investigate associations with sociocultural and environmental variables. Copyright © 2002 John Wiley & Sons, Ltd.