bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ability of iron(III)‐loaded carboxylated polyacrylamide‐grafted sawdust to remove phosphate ions from aqueous solution and fertilizer industry wastewater: Adsorption kinetics and isotherm studies
Authors: Unnithan Maya R. , Vinod V. P. , Anirudhan T. S. 
Published: October 2004

AbstractIron(III)‐loaded carboxylated polyacrylamide‐grafted sawdust was investigated as an adsorbent for the removal of phosphate from water and wastewater. The carboxylated polyacrylamide‐grafted sawdust was prepared by graft copolymerization of acrylamide and N,N′‐methylenebisacrylamide onto sawdust in the presence of an initiator, potassium peroxydisulfate. Iron(III) was strongly attached to the carboxylic acid moiety of the adsorbent. The adsorbent material exhibits a very high adsorption potential for phosphate ions. The coordinated unsaturated sites of the iron(III) complex of polymerized sawdust were considered to be the adsorption sites for phosphate ions, the predominating species being H2PO ions. Maximum removal of 97.6 and 90.3% with 2 g L−1 of the adsorbent was observed at pH 2.5 for an initial phosphate concentration of 100 and 250 μmol L−1, respectively. The adsorption process follows second‐order kinetics. Adsorption rate constants as a function of concentration and temperature and kinetic parameters, such as ΔG±, ΔH±, and ΔS±, were calculated to predict the nature of adsorption. The L‐type adsorption isotherm obtained in the sorbent indicated a favorable process and fitted the Langmuir equation model well. The adsorption capacity calculated by the Langmuir adsorption isotherm gave 3.03 × 10−4 mol g−1 of phosphate removal at 30°C and pH 2.5. The isosteric heat of adsorption was also determined at various surface loadings of the adsorbent. The adsorption efficiency toward phosphate removal was tested using industrial wastewater. Different reagents were tested for extracting phosphate ions from the spent adsorbent. About 98.2% of phosphate can be recovered from the adsorbent using 0.1M NaOH. Alkali regeneration was tried for several cycles with a view to recover the adsorbed phosphate and also to restore the adsorbent to its original state. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2541–2553, 2002
Spectral dispersion curves of polymeric birefringent textile fibers
Authors: Hamza A. A. , Fouda I. M. , Sokkar T. Z. N. , Sadik A. M. , El‐Bakary M. A. 
Published: October 2004

AbstractOptical Fourier transform (OFT) polarizing microscopy combined with variable‐wavelength interferometry (VAWI) was used for the determination of the spectral dispersion curves of birefringent textile fibers. We observed that the maximally bright circular fringe from the OFT technique corresponded to the anticoincidence case of the fiber fringe with the empty fringe from the VAWI technique and that the maximally dark fringe from the OFT technique corresponded to the coincidence case. With this combination of the two techniques, we identified the positions of the anticoincidence and coincidence when the VAWI technique was applied to overcome the difficulties of manually determining these positions. The intensity of the OFT patterns at the center was grabbed with a charge couple device camera and analyzed with a photodiode electrical circuit. The new observation was used for the determination of the spectral dispersion curves of the birefringence of polyethylene and aramide fibers. Microinterferograms are provided as illustrations. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2481–2488, 2002
Optimization of a commercial brake pad formulation
Authors: Lu Yafei , Tang Choong‐Fong , Wright Maurice A. 
Published: October 2004

AbstractA brake pad material used in a popular, commercially available vehicle that consisted of steel wool, iron powder, graphite, coke, styrene–butadiene rubber, MgO, BaSO4, and phenolic resin was tested with the friction assessment and screening test. The average friction coefficient (0.357) and total wear (19.75 wt %) were measured. An alternative friction material formulated with identical constituents but optimized with the golden section principle and relational grade analysis was produced in a laboratory environment. This material exhibited an average friction coefficient of 0.419 and a low total wear of 6.25 wt %. An analysis of component costs indicated that the large volume price of the commercial material, $1.01/kg, was less than that of the laboratory material, $1.21/kg. However, the performance/cost ratio of the new material was appreciably greater. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2498–2504, 2002
Embryology in the medical curriculum
Authors: Carlson Bruce M. 
Published: October 2004

AbstractEmbryology as a field is in a period of unprecedented change in its knowledge base. Similarly, this is a period of great change in medical curricular planning. One of the most significant questions in embryology education for medical students is how much of the “new” molecular embryology to mix with the “old” developmental anatomy approach. The other question is the most effective venue for instruction in medical embryology. Not all medical curricula have the same objectives; nor do they use the same educational approach. With that in mind, this review outlines several ways in which medical embryology can be offered and how it can be integrated into the medical curriculum. It also lays out topics that are worthy of inclusion in a modern embryology course or sequence. Anat Rec (New Anat) 269:89–98, 2002. © 2002 Wiley‐Liss, Inc.
Innovative testing method for an integrated radiology‐histology curriculum
Authors: Heidger Paul M. , Erkonen William , Kreiter Clarence , Pelsang Retta 
Published: October 2004

AbstractA module of radiology instruction was incorporated into an existing histology course for first‐year medical students (n = 177). An innovative testing methodology for assessing the instructional effectiveness of the integrated radiology‐histology module was developed and tested. Test items were designed to measure the students' ability to integrate the two disciplines successfully. Radiologic and histologic images were displayed at each of seven stations, to which the content of the images either were or were not related. The seven stations were incorporated into three traditional histology laboratory examinations. For purposes of data analysis, each test was divided into three components, including histology alone, histology in combination, and radiology in combination. Testing lengths were equated using the Spearman‐Brown statistical adjustment. Analysis of the test results showed the reliability coefficients to be comparable to the traditional testing methods used previously in the course. Correct responses were similar in all three sections, ranging between 85 to 97%. This methodology thus appears to be an effective means of testing an integrated curriculum. Anat Rec (New Anat) 269:113–117, 2002. © 2002 Wiley‐Liss, Inc.
Survey of gross anatomy, microscopic anatomy, neuroscience, and embryology courses in medical school curricula in the United States
Authors: Drake Richard L. , Lowrie D.J. , Prewitt Chantal M. 
Published: October 2004

AbstractDirectors of courses in the basic anatomical sciences in allopathic and osteopathic medical schools in the United States were surveyed regarding the present composition of their courses. Results indicate the majority of gross anatomy courses are in the range of 126 to 200 total course hours, and that laboratory dissection is a key component of these courses. The majority of microscopic anatomy courses are in the range of 61 to 100 total course hours, generally divided equally between lecture and laboratory components. Additionally, despite the availability of computer technology, microscopes are still used in the vast majority of microscopic anatomy courses. The majority of neuroscience courses are in the range of 71 to 90 total course hours, with most of these hours devoted to lectures. Embryology is usually taught in conjunction with gross anatomy, although some schools present it with the microscopic anatomy course or as a separate course. Most embryology courses are in the range of 6 to 20 total course hours, with only a few having a laboratory component. Anat Rec (New Anat) 269:118–122, 2002. © 2002 Wiley‐Liss, Inc.
S100P expression in human esophageal epithelial cells: Human esophageal epithelial cells sequentially produce different S100 proteins in the process of differentiation
Authors: Sato Nobuyuki , Hitomi Jiro 
Published: October 2004

AbstractExtracellular calcium ions (Ca2+) are important in regulating the differentiation of keratinocytes and squamous epithelial cells. To clarify the mechanisms involved in the differentiation of human esophageal epithelial cells (EECs), we used the primary culture of human EECs, which can be differentiated by increasing the concentration of extracellular Ca2+, and tried to reveal the extracellular Ca2+ inducible genes using a differential display (DD) method. We found that the calcium‐binding protein S100P showed a Ca2+‐inducible expression in the EECs. Our immunohistochemical study demonstrated that differentiated large EECs expressing S100P overlie immature proliferating cells which lack S100P immunoreactivity. S100P was detected in vivo in the suprabasal layers of the epithelium. These findings indicate that S100P expression is closely associated with differentiation of human EECs. We also investigated the expression of other S100 proteins, including S100A2, S100A6, and CAAF1 (S100A12), in human EECs. Most of the immature EECs were positive for S100A2 and S100A6, whereas the S100A12‐producing cells were similar to the S100P‐producing cells. In vivo, S100A12 was strongly detected on all epithelial cells except for basal and proliferating cells. S100A2 was detected on all of the epithelial cells. S100A6 was preferentially seen in the cells of basal layers. These findings suggest that within EECs S100 proteins might play important roles in cell differentiation during specific stages. Among them, S100P expression is unique in that this protein is transiently expressed during the early stage of differentiation. Anat Rec 267:60–69, 2002. © 2002 Wiley‐Liss, Inc.
Cellular changes in experimental left heart hypoplasia
Authors: Sedmera David , Hu Norman , Weiss Karen M. , Keller Bradley B. , Denslow Stewart , Thompson Robert P. 
Published: October 2004

AbstractHypoplastic left heart syndrome (HLHS) is a rare but deadly congenital malformation, which can be created experimentally in the chick embryo by left atrial ligation (LAL). The goal of this study was to examine the cellular changes leading to the profound remodeling of ventricular myocardial architecture that occurs in this model. Hypoplasia of left heart structures was produced after 3H‐thymidine prelabeling by partial LAL at stage 24, thereby reducing its volume, and redistributing blood preferentially to the developing right ventricle (RV). Controls included both sham‐operated and intact stage‐matched embryos. Survivors were studied 4 days after the ligation, when the heart organogenesis was essentially complete. Paraffin sections of the hearts were subjected to autoradiography and immunohistochemistry to detect changes in history of cell proliferation and expression of myosin, and growth factors implicated in cardiomyocyte proliferation. Sampling for apoptosis detection using TUNEL assay was done at stages 29 and 34. LAL resulted in decreased levels of proliferation in the left ventricular compact layer and trabeculae. The right ventricular compact layer also showed a slight decrease, but the trabeculae showed no differences. Anti‐myosin staining was significantly reduced in all compartments. The expression levels of growth factors were altered as well. Apoptosis was increased in the right atrioventricular mesenchyme, with no changes in the working myocardium. These data suggest that changes in cardiomyocyte proliferation play a significant role in the pathogenesis of HLHS. Anat Rec 267:137–145, 2002. © 2002 Wiley‐Liss, Inc.
GAPs in Slit‐Robo signaling
Authors: Ghose Aurnab , Van Vactor David 
Published: October 2004

AbstractNeuronal migration requires the integration of a number of diverse environmental cues and subsequent translation to specific responses such as directed cytoskeletal remodeling. Accurate knowledge of the signal transduction pathways linking activation of surface receptors to actin dynamics is necessary in order to understand the regulation of such processes. Activation of the Roundabout (Robo) receptor mediates a repulsive response in certain pioneering axons and migratory neurons. Recently, Wong et al.1 have described a signaling link between Robo activation and specific GTPase activity that appears to regulate neuronal migration. A novel family of GTPase regulators, responsive to Slit‐Robo engagement, has been identified and convincingly shown to alter the migration of neuronal cells. This study not only delineates a specific signaling route from guidance receptors to directed neuronal movement, but also offers clues towards potential regulatory mechanisms that ensure specificity of the Slit‐Robo response. BioEssays 24:401–404, 2002. © 2002 Wiley Periodicals, Inc.
Building the house around the plumbing*
Authors: Weinstein Brant 
Published: October 2004

AbstractSignaling between growing blood vessels and the tissues that they innervate has traditionally been viewed as a one‐way conversation, with organs and tissues supplying important cues for the growth and anatomical patterning of the blood vessels supplying them, but not vice‐versa. Two recent papers1,2 now provide evidence that blood vessels can have an important role in promoting the assembly of organs and tissues. These papers show that proper formation of the pancreas1 and liver2 and induction of endocrine and hepatic cell types in these endodermal organs requires inductive signals from blood vessels. BioEssays 24:397–400, 2002. Published 2002 Wiley Periodicals, Inc.
Spectroscopic study on structure of horseradish peroxidase in water and dimethyl sulfoxide mixture
Authors: Maeda Yasushi , Fujihara Maki , Ikeda Isao 
Published: October 2004

AbstractThe structure of horseradish peroxidase (HRP) in phosphate buffered saline (PBS)/dimethyl sulfoxide (DMSO) mixed solvents at different compositions is investigated by IR, electronic absorption, and fluorescence spectroscopies. The fluorescence spectra and the amide I spectra of ferric HRP [HRP(Fe3+)] show that overall structural changes are relatively small up to 60% DMSO. Although the amide I band of HRP(Fe3+) shows a gradual change in the secondary structure and a decrease in the contents of α helices, its fluorescence spectra indicate that the distance between the heme and Trp173 is almost constant. In contrast, the changes in the positions of the Soret bands for resting HRP(Fe3+) and catalytic intermediates (compounds I and II) and the IR spectra at the CO stretching vibration mode of carbonyl ferrous HRP [HRP(Fe2+)‐CO] show that the microenvironment in the distal heme pocket is altered, even with low DMSO contents. The large reduction of the catalytic activity of HRP even at low DMSO contents can be attributed to the structural transition in the distal heme pocket. In PBS/DMSO mixtures containing more than 70 vol % DMSO, HRP undergoes large structural changes, including a large loss of the secondary structure and a dissociation of the heme from the apoprotein. The presence of the components of the amide I band that can be assigned to strongly hydrogen bonding amide CO groups at 1616 and 1684 cm−1 suggests that the denatured HRP may aggregate through strong hydrogen bonds. © 2002 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 67: 107–112, 2002
Conformational preferences of substituted prolines in the collagen triple helix
Authors: Mooney Sean D. , Kollman Peter A. , Klein Teri E. 
Published: October 2004

AbstractResearchers have recently questioned the role hydroxylated prolines play in stabilizing the collagen triple helix. To address these issues, we have developed new molecular mechanics parameters for the simulation of peptides containing 4(R)‐fluoroproline (Flp), 4(R)‐hydroxyproline (Hyp), and 4(R)‐aminoproline (Amp). Simulations of peptides based on these parameters can be used to determine the components that stabilize hydroxyproline over proline in the triple helix. The dihedrals F–C–C–N, O–C–C–N, and N–C–C–N were built using a N‐β‐ethyl amide model. One nanosecond simulations were performed on the trimers [(Pro–Pro–Gly)10]3, [(Pro–Hyp–Gly)10]3, [(Pro–Amp–Gly)10]3, [(Pro–Amp1+–Gly)10]3, and [(Pro–Flp–Gly)10]3 in explicit solvent. The results of our simulations suggest that pyrrolidine ring conformation is mediated by the strength of the gauche effect and classical electrostatic interactions. © 2002 Wiley Periodicals, Inc. Biopolymers 64: 63–71, 2002
Determination of intermolecular distance for a model peptide of Bombyx mori silk fibroin, GAGAG, with rotational echo double resonance
Authors: Kameda Tsunenori , Nakazawa Yasumoto , Kazuhara Junko , Yamane Tsutomu , Asakura Tetsuo 
Published: October 2004

AbstractRotational echo double resonance NMR spectroscopy is applied for the determination of the distance of intermolecular chains of pentapeptide, GAGAG (G: Gly, A: Ala), a model typical of the crystalline domain in Bombyx mori silk fibroin. 1:4 mixture of G[1‐13C]AGAG and GAG[15N]AG with antiparallel β‐sheet structure was used to determine the distance of intermolecular hydrogen bonding between adjacent molecules within pleated sheet and the 13C–15N interatomic distance was determined to be 4.3 Å. On the other hand, 1:4 mixture of GAG[1‐13C]AG and GAG[15N]AG gave information on the interpleated sheet arrangement. When we assumed the same distances between two interpleated sheets, the distance was calculated to be 5.3 Å and the angle 15N–13C–15N was 180°. © 2002 Wiley Periodicals, Inc. Biopolymers 64: 80–85, 2002
A novel model of solute transport in a hollow‐fiber bioartificial pancreas based on a finite element method
Authors: Dulong Jean‐Luc , Legallais Cécile , Darquy Sylviane , Reach Gérard 
Published: October 2004

AbstractExtravascular bioartificial pancreas based on hollow fiber seems to be a promising treatment of diabetes mellitus. However, solutes mass‐transport limitations in such a device could explain its lack of success. To determine critical device parameters, we have developed a novel tridimensional model based on finite element method for glucose, insulin, and oxygen diffusion around an islet of Langerhans encapsulated in a hollow‐fiber section. A glucose ramp stimulation was applied outside the fiber and diffused to the islet. Concomitantly, a stationary oxygen partial pressure was applied outside the fiber, and determined local oxygen partial pressure on the islet environment. An insulin secretion model stimulated by a glucose concentration ramp and corrected by the local oxygen partial pressure was also implemented. Insulin secretion by the islet was thus computed as a response to glucose signal. The model predictions notably showed that the fiber radius had to be small enough to favor a fast response for insulin secretion and to ensure a maximal oxygen partial pressure in the islet environment. Besides the effect of fiber radius, a better islet oxygenation could be achieved by adjustments on the islet density, i.e., on the fiber length dedicated to a single islet. These hints should allow the future proposal of an optimal design for an implantable bioartificial pancreas. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 576–582, 2002.
Penicillin acylase‐catalyzed ampicillin synthesis using a pH gradient: A new approach to optimization
Authors: Youshko Maxim I. , van Langen Luuk M. , de Vroom Erik , van Rantwijk Fred , Sheldon Roger A. , Švedas Vytas K. 
Published: October 2004

AbstractThe penicillin acylase‐catalyzed synthesis of ampicillin by acyl transfer from D‐(–)‐phenylglycine amide (D‐PGA) to 6‐aminopenicillanic acid (6‐APA) becomes more effective when a judiciously chosen pH gradient is applied in the course of the process. This reaction concept is based on two experimental observations: 1) The ratio of the initial synthesis and hydrolysis rates (VS/VH) is pH‐dependent and exhibits a maximum at pH 6.5–7.0 for a saturated solution of 6‐APA; 2) at a fixed 6‐APA concentration below saturation, VS/VH increases with decreasing pH. Optimum synthetic efficiency could, therefore, be achieved by starting with a concentrated 6‐APA solution at pH 7 and gradually decreasing the pH to 6.3 in the course of 6‐APA consumption. A conversion of 96% of 6‐APA and 71% of D‐PGA into ampicillin was accomplished in an optimized procedure, which significantly exceeds the efficiency of enzymatic synthesis performed at a constant pH of either 7.0 or 6.3. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 589–593, 2002.
Effects of oxygen on engineered cardiac muscle
Authors: Carrier Rebecca L. , Rupnick Maria , Langer Robert , Schoen Frederick J. , Freed Lisa E. , Vunjak‐Novakovic Gordana 
Published: October 2004

AbstractConcentration gradients associated with the in vitro cultivation of engineered tissues that are vascularized in vivo result in the formation of only a thin peripheral tissue‐like region (e.g., ∼100 μm for engineered cardiac muscle) around a relatively cell‐free interior. We previously demonstrated that diffusional gradients within engineered cardiac constructs can be minimized by direct perfusion of culture medium through the construct. In the present study, we measured the effects of medium perfusion rate and local oxygen concentration (p) on the in vitro reconstruction of engineered cardiac muscle. Neonatal rat cardiomyocytes were seeded onto biodegradable polymer scaffolds (fibrous discs, 1.1 cm diameter × 2 mm thick, made of polyglycolic acid, 24 × 106 cells per scaffold). The resulting cell‐polymer constructs were cultured for a total of 12 days in serially connected cartridges (n = 1–8), each containing one construct directly perfused with culture medium at a flow rate of 0.2–3.0 mL/min. In all groups, oxygen concentration decreased due to cell respiration, and depended on construct position in the series and medium flow rate. Higher perfusion rates and higher p correlated with more aerobic cell metabolism, and higher DNA and protein contents. Constructs cultured at p of 160 mm Hg had 50% higher DNA and protein contents, markedly higher expression of sarcomeric α‐actin, better organized sarcomeres and cell junctions, and 4.5‐fold higher rate of cell respiration as compared to constructs cultured at p of 60 mm Hg. Contraction rates of the corresponding cardiac cell monolayers were 40% higher at p of 160 than 60 mm Hg. The control of oxygen concentration in cell microenvironment can thus improve the structure and function of engineered cardiac muscle. Experiments of this kind can form a basis for controlled studies of the effects of oxygen on the in vitro development of engineered tissues. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 617–625, 2002.