bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fixed Cost Magnitude, Fixed Cost Reporting Format, and Competitive Pricing Decisions: Some Experimental Evidence*
Authors: BUCHHEIT STEVE 
Published: March 2007

AbstractAlthough neoclassical economic theory predicts that fixed cost magnitude and fixed cost reporting format will not influence short‐term pricing decisions, these factors systematically affected pricing decisions in a duopoly experiment. Increasing fixed cost magnitude (a pure sunk cost in this study) across experimental conditions caused participants to first lower, then raise, competitive prices. Consistent with the psychological phenomenon of loss aversion, this change in pricing behavior reduced the frequency of reported losses. This study further reveals that the accounting format for reporting fixed costs influenced pricing behavior. Specifically, participants receiving capacity costing feedback reports established increasingly lower selling prices relative to the prices established by participants receiving contribution margin feedback reports. Given that a very simple cosmetic reporting manipulation produced increasingly significant competitive pricing differences in a market setting, this study provides evidence that functional fixation is not necessarily eliminated by market forces.
Corporate Investment Incentives and Accounting‐Based Debt Covenants*
Authors: Douglas Alan V. S. 
Published: March 2007

AbstractThis paper studies the conditions under which accounting‐based debt covenants increase firm value in a setting that incorporates the conflicting incentives of shareholders, bondholders, and managers. We construct a model in which debt is needed to discipline managerial investment decisions despite endogenous compensation contracts. We show that accounting covenants increase value when (1) debt serves as a credible commitment to penalize poor investment decisions; (2) the firm faces other (exogenous) sources of uncertainty that can make debt risky despite good investment decisions; and (3) accounting information serves as a contractible proxy for firm's economic performance. In these circumstances, accounting covenants ensure that shareholders do not offer compensation schemes that would encourage bondholder wealth expropriation when the debt becomes risky. A covenant specifying a required level of accounting performance provides additional bondholder power when performance is low. An accounting‐based dividend covenant allows a disbursement to maintain investment incentives when performance is high without allowing dividend‐based expropriation. The optimal covenants depend on the reliability of accounting information, and the interaction between accounting performance and the different incentive conflicts provides new insight into the empirical literature on accounting‐based covenants.
Synthesis and evaluation of anti-inflammatory, analgesic, ulcerogenic and lipid peroxidation properties of ibuprofen derivatives
Authors: Amir Mohammad , Kumar Shikha 
Published: March 2007

Synthesis and evaluation of anti-inflammatory, analgesic, ulcerogenic and lipid peroxidation properties of ibuprofen derivatives
In order to reduce the ulcerogenic effect of ibuprofen, its carboxylic group has been converted into 5-membered heterocyclic rings. Various 1,3,4-oxadiazoles (3-8, 16-21), 1,2,4-triazoles (22-27), 1,3,4-thiadiazoles (28-30), and 1,2,4-triazine (9) derivatives of ibuprofen were prepared by cyclization of 2-(4-i-butylphenyl) propionic acid hydrazide (2) and N1-[2-(4-i-butylphenyl) propionyl]-N4-alkyl/arylthiosemicarbazides (10-15) under various reaction conditions. The cyclized derivatives were screened for their anti-inflammatory activity by the carrageenan induced rat paw edema method and showed 50 to 86% inhibition, whereas the standard drug ibuprofen showed 92% inhibition at the same oral dose. Five compounds, 7, 16, 18, 22 and 30 that showed more than 80% anti-inflammatory activity were selected to study their analgesic, ulcerogenic and lipid peroxidation activities. All the tested compounds showed a significant reduction in ulcerogenic activity compared to ibuprofen through the severity index 0.5 to 0.8, vs. ibuprofen 1.8. The compounds, that showed less ulcerogenic effect also produced less malondialdehyde content in gastric mucosa, which is one of the end products of lipid peroxidation. The results of biological studies showed that oxadiazole derivative 16 as the lead molecule with maximum anti-inflammatory, analgesic and minimum ulcerogenic and lipid peroxidation activities.
Influence of process variables on release properties of paracetamol tablets
Authors: Alebiowu Gbenga , Itiola Oludele 
Published: March 2007

Influence of process variables on release properties of paracetamol tablets
A 23 factorial experimental design has been used to quantitatively study individual and interaction effects of the nature of binder (N), binder concentration (c) and relative density of tablet (d) on the disintegration time (DT) and dissolution times, t1, t50 and t90, of paracetamol tablet formulations. The factorial design was also used to study the quantitative effects of pregelatinization of starch binders on these parameters, i.e., N, c and d. In general, the most common ranking of the individual effects on DT, t1, t50 and t90 for native/native, pregelatinized/pregelatinized and native/pregelatinized starch binder formulations was c > d > N. For interaction effects, the most common ranking was N-c > c-d > N-d for all formulations. The results generally showed that c can considerably affect DT, t1, t50 and t90 of the tablets.
Rapid titrimetric and spectrophotometric methods for salbutamol sulphate in pharmaceuticals using N-bromosuccinimide
Authors: Basavaiah Kanakapura , Somashekar Bankavadi , Ramakrishna Veeraiah 
Published: March 2007

Rapid titrimetric and spectrophotometric methods for salbutamol sulphate in pharmaceuticals using N-bromosuccinimide
One titrimetric and two spectrophotometric methods which are simple, sensitive and rapid are described for the assay of salbutamol sulphate (SBS) in bulk drug and in tablet dosage forms using N-bromosuccinimide (NBS) and two dyes, rhodamine-B and methylene blue, as reagents. In titrimetry, aqueous solution of salbutamol sulphate is treated with a measured excess of NBS in acetic acid medium and after the oxidation of SBS is complete, the unreacted oxidant is determined iodometrically. Spectrophotometric methods entail addition of a known excess of NBS in acid medium followed by the determination of residual oxidant by reacting with a fixed amount of either rhodamine B and measuring the absorbance at 555 nm (method A) or methylene blue and measuring the absorbance at 665 nm (method B). In all methods, the amount of NBS reacting corresponds to the amount of SBS content. Titrimetric method is applicable over 1.74 x 10-4 - 8.68 x 10-4 mol L-1 range and the reaction stoichiometry is found to be 1:6 (SBS:NBS). In spectrophotometric methods, the absorbance is found to increase linearly with the concentration of SBS, which is corroborated by the correlation of coefficients of 0.9993 and 0.9988 for method A and method B, respectively. The systems obey Beer's law for 0.25-1.75 μg mL-1 (method A) and 0.5-5.0 μg mL-1 (method B). The calculated apparent molar absorptivity values were found to be 2.10 x 105 and 6.16 x 104 L mol-1 cm-1, for method A and method B, respectively. The limits of detection and quantification are also reported for both spectrophotometric methods. Intraday and inter-day precision and accuracy for the developed methods were evaluated. The methods were successfully applied to the assay of SBS in tablet and capsule formulations and the results were statistically compared with those of a reference method. No interference was observed from common tablet adjuvants. The accuracy and reliability of the methods were further ascertained by recovery experiments via the standard-addition technique.
Liquisolid technique as a tool for enhancement of poorly water-soluble drugs and evaluation of their physicochemical properties
Authors: Javadzadeh Yousef , Siahi Mohammad , Asnaashari Solmaz , Nokhodchi Ali 
Published: March 2007

Liquisolid technique as a tool for enhancement of poorly water-soluble drugs and evaluation of their physicochemical properties
The potential of liquisolid systems to improve the dissolution properties of a water-insoluble agent (indomethacin) was investigated. In this study, different formulations of liquisolid tablets using different co-solvents (non-volatile solvents) were prepared and the effect of aging on the dissolution behaviour of indomethacin liquisolid compacts was investigated. To evaluate any interaction between indomethacin and the other components in liquisolid formulations, X-ray powder diffraction (XPD) and differential scanning calorimetry (DSC) were used. Dissolution test was carried out at two different pH, 1.2 and 7.2, to simulate the stomach or intestine fluid, respectively. The results showed that liquisolid formulations exhibited significantly higher drug dissolution rates at pH 1.2 and 7.2 compared to compacts prepared by the direct compression technique. The enhanced rate of indomethacin dissolution from liquisolid tablets was probably due to an increase in wetting properties and surface area of drug particles available for dissolution. In order to investigate the effect of aging on the hardness and dissolution rate of liquisolid compacts, the formulations were stored at 25 °C/75% relative humidity for a period of 12 months. The results showed that aging had no significant effect on dissolution profiles of liquisolid tablets. Liquisolid compacts containing propylene glycol as vehicle produced higher dissolution rates in comparison with liquisolid compacts containing PEG 400 or Tween 80 of the same concentration. The DSC and XPD results showed no changes in crystallinity of the drug and interaction between indomethacin and excipients (Avicel and silica) during the process.
Der σ‐CAM‐Mechanismus: σ‐Komplexe als Schlüssel der σ‐Bindungsmetathese bei späten Übergangsmetallen
Authors: Perutz Robin N. , Sabo‐Etienne Sylviane 
Published: March 2007

AbstractKomplexe, in denen eine σ‐H‐E‐Bindung (E = H, B, Si, C) als ein Zweielektronendonor zum Metall agiert, werden als σ‐Komplexe bezeichnet. Hinweise darauf, dass σ‐Liganden ohne Wechsel der Oxidationsstufe ineinander umgewandelt werden können, finden sich bei C‐H‐Aktivierungsreaktionen mit Isotopenaustausch und in dynamischen Umlagerungen von σ‐Komplexen (siehe Vortitel). Über diese beiden Reaktionswege können Metathesen von M‐E‐Bindungen an späten Übergangsmetallen ablaufen, und wir nennen diesen Prozess σ‐Komplex‐vermittelte Metathese oder σ‐CAM. Die Reaktion unterscheidet sich mechanistisch von den bekannten σ‐Bindungsmetathesen (die typisch für d0‐Metalle sind und ohne Intermediat ablaufen) und von den oxidativen Additionen/reduktiven Eliminierungen (bei denen Intermediate mit wechselnden Oxidationsstufen auftreten und die manchmal unter Beteiligung von σ‐Komplexen ablaufen). Es gibt Beispiele für σ‐CAM‐Mechanismen in der Katalyse, insbesondere in der Alkanborylierung und beim Isotopenaustausch von Alkanen. σ‐CAM‐Mechanismen können außerdem auch bei Silylierungen und der Alkenhydrierung auftreten.
Synthesis and characterization of polyacrylamide‐grafted coconut coir pith having carboxylate functional group and adsorption ability for heavy metal ions
Authors: Anirudhan T. S. , Unnithan M. R. , Divya L. , Senan P. 
Published: March 2007

AbstractThe present investigation was undertaken to evaluate the effectiveness of a new adsorbent prepared from coconut coir pith (CP), a coir industry‐based lignocellulosic residue in removing metal ions from aqueous solutions. The adsorbent (PGCP‐COOH) having a carboxylate functional group at the chain end was prepared by grafting polyacrylamide onto CP using potassium peroxydisulphate as an initiator and in the presence of N,N′‐methylenebisacrylamide as a crosslinking agent. The adsorbent was characterized by infrared (IR) spectroscopy, thermogravimetry (TG), X‐ray diffraction (XRD) patterns, scanning electron microscopy (SEM), and potentiometric titration. The adsorbent exhibits very high adsorption potential for the removal of Pb(II), Hg(II), and Cd(II) ions from aqueous solutions. The optimum pH range for metal ion removal was found to be 6.0–8.0. The adsorption process follows a pseudo‐second‐order kinetic model. The adsorption capacities for Hg(II), Pb(II), and Cd(II) calculated using the Langmuir isotherm equation were 254.52, 189.49, and 63.72 mg g−1, respectively. Adsorption isotherm experiments were also conducted for comparison with a commercial carboxylate form cation exchanger. Different industry wastewater samples were treated by the PGCP‐COOH to demonstrate its efficiency in removing heavy metals from wastewater. The reusability of the PGCP‐COOH was also demonstrated using 0.2M HCl. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3670–3681, 2007
Miscibility and properties of semi‐interpenetrating polymer networks based on polyurethane and nitroguar gum
Authors: Huang Yihong , Fan Qingchun , Xiao Chaobo 
Published: March 2007

AbstractFilms from castor oil‐based polyurethane (PU) prepolymer and nitroguar gum (NGG) with different contents (10–70 wt %) were prepared through solution casting method. The networks of PU crosslinked with 1,4‐butanediol were interpenetrated by linear NGG to form semi‐interpenetrating polymer networks (semi‐IPNs) in the blend films. The miscibility, morphology, and properties of the semi‐IPNs coded as PUNG films were investigated with Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, dynamic mechanical thermal analysis, wide‐angle X‐ray diffraction, density measurement, ultraviolet spectroscopy, thermogravimetric analysis, tensile, and solvent‐resistance testing. The results revealed that the semi‐IPNs films have good miscibility over the entire composition ratio of PU to NGG under study. The occurrence of hydrogen‐bonding interaction between PU and NGG played a key role in improvement of the material performance. Compared with the pure PU film, the PUNG films exhibited higher values of tensile strength (11.7–28.4 MPa). Meanwhile, incorporating NGG into the PU networks led to an improvement of thermal stability and better solvent‐resistance of the resulting materials. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104, 4068–4079, 2007
Hydraulic permeability of a hydrogel‐based contact lens membrane for low flow rates
Authors: Pishko Gregory L. , Lee Sung‐Jin , Wanakule Prinda , Sarntinoranont Malisa 
Published: March 2007

AbstractHydrogels, widely used for contact lenses, are a class of materials that consists of both fluid and solid components. The aqueous fluid phase is supported by a solid polymer matrix. In this study, we characterize the water transport characteristics of an Etafilcon‐A (copolymer of 2‐hydroxyethyl methacrylate and methacrylic acid) membrane. A flow rate‐controlled permeameter consisting of a syringe pump, membrane holder, pressure transducer, and tubing was developed and used to measure the pressure drop across a flat membrane (average thickness ∼ 686 μm ± 40). The relation between velocity and pressure drop was measured. These data were fit to rigid media and biphasic models of 1‐D flow to determine hydraulic permeability, k = 1.80 × 10−14 m4/N s. The results provide insight into the fluid flow properties of this hydrogel under low flow and low pressure conditions (<3 kPa). Physiological implications of these measured parameters on flow and deformation across the lens due to blinking are discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3730–3735, 2007
Investigation of short range ordering in PES/PEES alternative copolymer by means of radial distribution functions derived from X‐ray diffraction
Authors: Zhou Xiao‐Ming , Jiang Zhen‐Hua 
Published: March 2007

AbstractTwo samples of poly(ether sulfone)/poly (ether ether sulfone) alternative copolymer, showing marked differences in tensile behavior due to different thermal histories, were investigated by radial distribution function (RDF) methods. The RDF patterns were virtually identical and showed that the short range order (0–14 Å) in the samples had been essentially unaffected by the annealing procedures. Two intramolecular distances in the polymer repeat unit were successfully resolved in the RDF pattern. However, there were only suggestions of broad peaks at r = 5.5 Å and r = 11 Å attributable to intermolecular ordering, indicating that little intermolecular ordering had occurred in either sample. The appearance of two peaks at ∼ 5 Å periodic suggested the existence of more or less parallel chain segments in the copolymers. Explanations of the different tensile properties of the two samples which assume a significant short range reordering on annealing are thus ruled out on the available evidence. A more highly annealed sample was examined to assess the sensitivity of the RDF method to short range intermolecular ordering. The RDF plot of this sample showed a marked periodicity peaking at intervals of ∼ 5 Å which was attributed to intermolecular ordering, thus confirming the above conclusion. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3746–3750, 2007
New bleeding model of additives in a polypropylene film under atmospheric pressure
Authors: Wakabayashi Makoto , Kohno Takayuki , Kimura Tokutaro , Tamura Satoshi , Endoh Masahiko , Ohnishi Satoru , Nishioka Toshikatsu , Tanaka Yoshikatsu , Kanai Toshitaka 
Published: March 2007

AbstractMany additives are commercially used to add more favorable qualities to films. The bleeding process by which the additive in a film comes to the surface is considered. A new bleeding model of additives in a polypropylene film under atmospheric pressure was investigated. Solubility and diffusion are found to be important for explaining this bleeding process. The solubilities and diffusion coefficients of higher fatty acid amides such as erucamide (13‐cis‐docosenamide) and behenamide (docosanamide) were determined between 40 and 70°C and the difference between the solubilities and the diffusion coefficients was discussed. The experimental results are explained more precisely by assuming two transport processes between the crystalline regions and the amorphous ones. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3751–3757, 2007
Synthesis and characterization of a novel polyurethane elastomer based on CO2 copolymer
Authors: Xu Shouping , Zhang Min 
Published: March 2007

AbstractNovel poly(ethylene ether carbonate) polyurethane elastomers (PEC‐PUE) based on methylene diphenyl diisocyanate (MDI) and poly(ethylene ether carbonate) diol (PEC) were prepared and characterized. The diol PEC was a new material obtained by copolymerization of ethylene oxide and CO2 in the presence of polymer supported bimetallic catalyst (PBM). When the diol PEC reacted with MDI and with 1,4‐butanediol as the chain extender, a novel polyurethane elastomer can be formed. The elastomer was characterized by FTIR and 1H NMR. The mechanical properties were studied by tensile set and the thermal properties were studied by TGA. Results of the tests indicated that mechanical strength of the elastomer can be improved by adjusting the ratio of NCO/OH. The thermal stability as well as tensile strength (TS) decreased sharply after being exposed to moisture and with bonded water in the polymer structure. It was also discovered that as the bonded water evaporated, both the thermal stability and TS would recover. Moreover, shape memory behaviors of the elastomer were also studied, and it was found that all the samples tested returns to its original shape in 100 s. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3818–3826, 2007
Rheological and electrical properties of bentonite in anionic polystyrene sulfonate and nonionic poly(vinyl alcohol)
Authors: Mostafa Bassem A. , Assaad Faiz F. 
Published: March 2007

AbstractThe flow properties of bentonite were studied with a combination of anionic polystyrene sulfonate (molecular weight = 70,000 g/mol) and nonionic poly(vinyl alcohol) (molecular weight = 50,000 g/mol). This combination had a significant effect on clay suspensions depending on the sequence of the polymer addition. The addition of 50 mg/L anionic polystyrene sulfonate followed by 200 mg/L nonionic poly(vinyl alcohol) improved the rheological properties with a 7% bentonite suspension, especially at 20°C and after 24 h of aging. However, by the reversal of this addition sequence, the rheological properties of bentonite suspensions were reduced. The ζ potential of bentonite suspensions of the individual polymers at the same concentration was −42 mV for polystyrene sulfonate and −63 mV for poly(vinyl alcohol). The combined effect of anionic polystyrene sulfonate followed by nonionic poly(vinyl alcohol) noticeably changed the ζ potential (−95 mV). With the reversal of the addition sequence, this parameter did not change. Potential energy profiles were constructed to investigate the suspension stability. Potential energy profiles of polystyrene sulfonate added to bentonite suspensions and followed by poly(vinyl alcohol) produced high repulsion potential energy between clay surfaces, reflecting high suspension stability. By the reversal of this sequence, a significant reduction of the energy barrier was observed. On the basis of the rheological and electrical properties of this system, the addition of polystyrene sulfonate followed by poly(vinyl alcohol) provides a promising tendency for a 7% clay concentration to meet desirable drilling mud properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3886–3894, 2007
Thermotropic color changing nanoparticles prepared by encapsulating blue polystyrene particles with a poly‐N‐isopropylacrylamide gel
Authors: Yuan Bing , Wicks Douglas A. 
Published: March 2007

AbstractWater‐dispersed thermotropic nanoparticles with core‐shell structures were synthesized by the in situ polymerization of a lightly crosslinked shell of poly(N‐ isopropylacrylamide) [poly(NIPAM)] onto blue polystyrene cores. At room temperature, the thermal responsive outer shell is hydrophilic and is in a fully swollen gel state; but as the temperature is raised above 31°C, it becomes increasingly hydrophobic and eventually collapses as the temperature reaches the lower critical solution temperature (LCST) of the poly(NIPAM). Passing through the LCST has a drastic effect on the color of the latex solution, which exhibited an intense blue color at room temperature and gradually pales or lightens as the temperature is raised above 31°C. Analysis using spectroscopic and dynamic light scattering techniques showed that it is a reversible process. Microscopy evaluation of samples dried by the evaporation of water at temperatures above and below the LCST revealed that the swollen/collapse state of the polymer shell influenced the morphology of the dry state. Drying at room temperature resulted in thin films in which only particles of sizes corresponding to the polystyrene core are clearly seen in the microscopy images; but for samples prepared above the LCST, the images revealed a morphology made of much larger particles with diameters of 400–500 nm. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007