bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of neutral sodium hydrogen phosphate on the setting property and hemostatic ability of hydroxyapatite putty as a local hemostatic agent for bone
Authors: Momota Yukihiro , Miyamoto Youji , Ishikawa Kunio , Takechi Masaaki , Yuasa Tetsuya , Tatehara Seiko , Nagayama Masaru 
Published: March 2004

AbstractHydroxyapatite (HAP) putty has been reported to have good hemostatic ability and excellent biocompatibility. Although the setting reaction of HAP putty and resulting transformation to HAP is the reason for this excellent biocompatibility, it also limits the handling period. In this study, the relationship between the setting reaction of HAP putty and its hemostatic ability was investigated, where neutral sodium hydrogen phosphate concentration and postpreparation time were used as indexes. A higher concentration of neutral sodium hydrogen phosphate was found to result in decreased hemostatic ability. The hemostatic ability of HAP putty decreased with time after its preparation; thus it was important to use HAP putty within 10 min after its preparation. The adhesive strength of HAP putty to bone increased with time. Therefore reliable hemostasis can be expected with HAP putty. Although the limited handling time is a drawback, HAP putty is thought to have a good potential as a hemostatic agent—it is highly reliable, and has a high hemostatic ability with excellent biocompatibility. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 99–103, 2004
Hydrolytic degradation and cracks in resin‐modified glass‐ionomer cements
Authors: Fano Luca , Fano Vincenzo , Ma Wanyun , Wang Xiaoguang , Zhu Feng 
Published: March 2004

AbstractWater‐absorption affects the basic properties of resin‐modified glass‐ionomer cements (RMGICs). Fick's law is usually invoked to explain the absorption process. The purpose of this study is to show that the absorption in accordance with the Fickian model cannot be extended to the whole of the specimen, and that microcrack formation is the main degradation mechanism for specimens cured in a closed environment. For this purpose, flat disk‐shaped paste specimens 1.5 mm thick (aspect ratio 4), irradiated in closed conditions between two glass slides and stored in water for ≈20 months, were analyzed periodically gravimetrically and under confocal fluorescence microscopy, with absorbed eosin used as the fluorescent probe. At pH 7.0, the specimen surface (10–20 micrometers in depth) absorbed water rapidly, swelled, and disintegrated in 20–40 days. Long‐term storage produced isolated cracks and grains, no progress in the swelling, and a slow weight decrease. A lower pH (pH 3.5) produced a significant increase of the number of microcracks. The decrease in the irradiation time (30 s or less) enhanced the erosion process, producing very broad cracks. It was concluded that the prevalent mechanism of long‐term hydrolytic degradation was based on the slow formation of cracks, whereas only in the early stage of storage did absorption occur quickly in accordance with the Fickian diffusion. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 87–93, 2004
Surface treatment of injectable strontium‐containing bioactive bone cement for vertebroplasty
Authors: Zhao F. , Lu W. W. , Luk K. D. K. , Cheung K. M. C. , Wong C. T. , Leong J. C. Y. , Yao K. D. 
Published: March 2004

AbstractA novel injectable bioactive bone‐bonding cement (SrHAC) composed of strontium‐containing hydroxyapatite (Sr‐HA) as the inorganic filler and bisphenol A diglycidylether dimethacrylate (Bis‐GMA) as the organic matrix for vertebroplasty was developed previously. In this study, the Sr‐HA powders were surface treated with methyl methacrylate (MMA) to improve the interface integration of the two phases. After surface treatment, the compression strength and Young's modulus, which were tested after immersion in distilled water at 37 °C for 24 h according to ISO 5833, were increased by 68.65 % (p < .001) and 31.02% (p < .001), respectively. The bending strength and bending stiffness of the bioactive bone cement were significantly improved by 54.44% (p < .001) and 83.90% (p < .001). In addition, the handling property of the cement was also enhanced. In vitro biomechanical testing showed that the stiffness of the fractured spine recovered to 82.5% (p < .01) of the intact condition after cementation with surface‐treated SrHAC. The failure load of the spine cemented with original and MMA‐treated SrHAC improved by 14.25% (p < .05) and 46.91% (p < .05) in comparison with the fractured spines. Results from this study revealed that the MMA‐treated SrHAC has a better mechanical effect for orthopedic applications. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 79–86, 2004
Transmittance of a bioceramic dental restorative material based on calcium aluminate
Authors: Engqvist Håkan , Lööf Jesper , Uppström Stina , Phaneuf Mike W. , Jonsson Jacob C. , Hermansson Leif , Ahnfelt Nils‐Otto 
Published: March 2004

AbstractThis article investigates the transmittance of a new ceramic filling material as a function of time, thickness, wavelength, and addition of pigments. In the hardened state the ceramic material is composed of hydrates, calcium aluminate, and glass fillers. The radiopacity of the investigated material is also measured. The results of the transmittance are compared to a commercial glass ionomer cement (Fuji II) and resin composite (Tetric Ceram). The transmittance increased with time from low values after 1 h to values close to the glass ionomer cements after 1 week. The resin composite had almost twice the transmittance as the calcium aluminate material and the glass ionomer cement. The amount of light passing through the material was dependent on both the sample thickness and the wavelength. Samples of 0.5‐mm thickness transmitted almost twice as much as 1‐mm‐thick samples. Regarding the wavelength, blue light was scattered very effectively (low transmittance), whereas red light was not (high transmittance). Addition of pigments lowered the transmittance. The radiopacity was slightly higher than that of enamel. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 94–98, 2004
Car‐Parrinello simulations with a real space method
Authors: Schmid Rochus 
Published: March 2004

AbstractAn approach for Car‐Parrinello type molecular dynamics simulations using real space discretized wave functions is presented. The implementation uses a higher order finite difference approximation for the Laplacian in the kinetic energy operator and in the Poisson equation for the evaluation of the Hartree energy. Norm conserving pseudopotentials are employed to replace the nucleus‐core interactions. Both nuclei and wave functions are propagated with a second‐order Verlet propagator with a timestep comparable to standard plane wave implementations. The orthonormality constraints are fulfilled via Lagrange multipliers. Both periodic and nonperiodic boundary conditions can directly be imposed within the real space approach. In order to maintain energy conservation both forces on the nuclei and the wave functions must be sufficiently accurate. It is shown that the spurious energy dependence on the nuclear positions with respect to the grid points, which is an inevitable artifact of the discretization, is mirrored in the nuclear forces, and does not affect energy conservation. In contrast to the plane wave methodology, the Hartree energy is calculated via an iterative solution of the Poisson equation. As a result, the quality of the forces on the wave function crucially depends on its convergence, as well as on the accuracy of the approximation for the boundary values in nonperiodic calculations. The influence of these factors on the energy conservation is investigated. It is shown that Car‐Parrinello simulations can be performed with real space wave functions, given a proper prescription to calculate the Hartree potential is used. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 799–812, 2004
Continuous medium theory for nonequilibrium solvation: II. Interaction energy between solute charge and reaction field and single‐sphere model for spectral shift
Authors: Li Xiang‐Yuan , Fu Ke‐Xiang , Zhu Quan , Shan Min‐Hua 
Published: March 2004

AbstractOn the basis of continuous medium theory, a model for evaluation of spectral shifts in solution has been developed in this work. The interaction energy between solute dipole and reaction field and the self‐energy of the reaction field have been formulated through derivations. Applying the interaction energy expression together with the point dipole approximation to the case of spherical cavity produces new formulations of spectral shifts. The same expression of electrostatic free energy of the nonequilibrium state is achieved by integrating the change of the electrostatic free energy for a charging process. Moreover, generalized formulations evaluating spectral shifts have been established in the charge‐potential notation, and the reduction of them to the point dipole case consistently leads to the same formulations of spectral shifts as those by interaction energy approach. Mutual supports provide convincing evidences for the reliability of the present results. In this work, attentions are particularly paid to the conclusion of zero self‐energy of the reaction field, which is different from the previous theory. Reasoning and arguments are given on this point. From the present derivations, it is concluded that the spectral shifts of light absorption and emission were theoretically exaggerated in the past, in particular, by a factor of 2 for the spectral shift sum. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 835–842, 2004
Modification of the Wiener index 4
Authors: Yang Feng , Wang Zhen‐Dong , Huang Yun‐Ping 
Published: March 2004

AbstractA novel topological index WF is defined by the matrices X, W, and L as WF = XWL. Where L is a column vector expressing the characteristic of vertices in the molecule; X is a row vector expressing the bonding characteristics between adjacent atoms; W is a reciprocal distance matrix. The topological index WF, based on the distance‐related matrix of a molecular graph, is used to code the structural environment of each atom type in a molecular graph. The good QSPR/QSAR models have been obtained for the properties such as standard formation enthalpy of inorganic compounds and methyl halides, retention indices of gas chromatography of multiple bond‐containing hydrocarbons, aqueous solubility, and octanol/water partition of benzene halides. These models indicate that the idea of using multiple matrices to define the modified Wiener index is valid and successful. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 881–887, 2004
The calculation of the vibrational frequencies of crystalline compounds and its implementation in the CRYSTAL code
Authors: Pascale F. , Zicovich‐Wilson C. M. , López Gejo F. , Civalleri B. , Orlando R. , Dovesi R. 
Published: March 2004

AbstractThe problem of numerical accuracy in the calculation of vibrational frequencies of crystalline compounds from the hessian matrix is discussed with reference to α‐quartz (SiO2) as a case study and to the specific implementation in the CRYSTAL code. The Hessian matrix is obtained by numerical differentiation of the analytical gradient of the energy with respect to the atomic positions. The process of calculating vibrational frequencies involves two steps: the determination of the equilibrium geometry, and the calculation of the frequencies themselves. The parameters controlling the truncation of the Coulomb and exchange series in Hartree–Fock, the quality of the grid used for the numerical integration of the Exchange‐correlation potential in Density Functional Theory, the SCF convergence criteria, the parameters controlling the convergence of the optimization process as well as those controlling the accuracy of the numerical calculation of the Hessian matrix can influence the obtained vibrational frequencies to some extent. The effect of all these parameters is discussed and documented. It is concluded that with relatively economical computational conditions the uncertainty related to these parameters is smaller than 2–4 cm−1. In the case of the Local Density Approximation scheme, comparison is possible with recent calculations performed with a Density Functional Perturbation Theory method and a plane‐wave basis set. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 888–897, 2004
Carbon‐14 wiggle‐match dating of peat deposits: advantages and limitations
Authors: Blaauw Maarten , Van Geel Bas , Mauquoy Dmitri , Van Der Plicht Johannes 
Published: March 2004

AbstractCarbon‐14 wiggle‐match dating (WMD) of peat deposits uses the non‐linear relationship between 14C age and calendar age to match the shape of a series of closely spaced peat 14C dates with the 14C calibration curve. The method of WMD is discussed, and its advantages and limitations are compared with calibration of individual dates. A numerical approach to WMD is introduced that makes it possible to assess the precision of WMD chronologies. During several intervals of the Holocene, the 14C calibration curve shows less pronounced fluctuations. We assess whether wiggle‐matching is also a feasible strategy for these parts of the 14C calibration curve. High‐precision chronologies, such as obtainable with WMD, are needed for studies of rapid climate changes and their possible causes during the Holocene. Copyright © 2004 John Wiley & Sons, Ltd.
Tephrostratigraphical evidence for the timing of pleistocene explosive volcanism at Jan Mayen
Authors: Hunt John B. 
Published: March 2004

AbstractWavelength dispersive (WDS) electron microprobe analysis of glass shards recovered from Pleistocene sediments at Ocean Drilling Program Hole 907A (Leg 151) has been used to define key Pleistocene tephrochronostratigraphical markers for the Greenland–Iceland–Norwegian (GIN) seas. Two tephras have particularly distinctive geochemistry, making them useful as marker horizons in cores from the Iceland Plateau, and potentially further afield. These tephras enable the construction of a sedimentation rate history that indicates reduced sediment deposition in the mid‐Brunhes magnetochron, possibly through reduced carbonate preservation. No significant geochemical weathering of the Iceland Plateau tephra sequence has occurred. The geochemical signature of a key tephra, dated to 577–640 ka, can be attributed to the Jan Mayen rock suite, demonstrating unambiguously the explosive potential of Jan Mayen and its potential to contribute to the North Atlantic tephra record. Copyright © 2004 John Wiley & Sons, Ltd.
Characterisation of frozen orange juice by ultrasound and wavelet analysis
Authors: Lee Suyong , Pyrak‐Nolte Laura J , Cornillon Paul , Campanella Osvaldo 
Published: March 2004

AbstractUltrasound technology was used to analyse the freezing behaviour of orange juice. The ultrasonic properties of orange juice, specifically velocity and attenuation coefficient, were characterised as the temperature was decreased from 20 to −50 °C. The results were compared with NMR free induction decay data and correlated with the amount of unfrozen water present in the frozen sample. The velocities of longitudinal waves (P‐wave) and shear waves (S‐wave) in frozen orange juice were measured, yielding values of around 4000 and 2000 m s−1 respectively. They were related to the amount of unfrozen water in the frozen sample. The elastic moduli of the samples at different temperatures were obtained from the measured ultrasonic velocities. Significant changes in the attenuation of the ultrasonic waves propagated through the frozen sample were observed as a result of ice nucleation and growth. Information about the spectral behaviour of the ultrasound signal was obtained by means of wavelet analysis. The analysis provided a direct measure of the spectral content of the ultrasonic waves over time and showed the variation in the ultrasonic velocity dispersion with temperature. Significant velocity dispersions occurred for frequencies less than 1 MHz. Copyright © 2004 Society of Chemical Industry
Variation in the composition of Cretan avocado cultivars during ripening
Authors: Vekiari Stavroula A , Papadopoulou Parthena P , Lionakis Spiros , Krystallis Athanasios 
Published: March 2004

AbstractThe effect of ripening on the chemical characteristics of fruits of the avocado (Persea americana) cultivars Ettinger, Fuerte and Hass was investigated. A study of some quality parameters of these main avocado cultivars grown on the island of Crete was performed. As the fruit ripened, a decrease in the moisture content was observed, with a high degree of correlation for all the cultivars. At the same time an increase in the fat and protein contents was measured. The content of total sugars was high in the unripe fruit but decreased during ripening. The fatty acid composition of the oil extracted from the fruit pulp was determined by gas chromatographic analysis. The oil of the edible portion of the fruit was rich in oleic, palmitic, linoleic and palmitoleic acids, while stearic acid was present in small quantities. During the ripening process the amount of palmitic acid decreased and that of oleic acid increased in all the cultivars. The ratio of polyunsaturated to saturated fatty acids, which is considered as an indicator of the nutritional value of the fruit, was also calculated. No significant differences were observed between the cultivars. Principal component analysis was also performed to examine the relationship among the quality variables of the cultivars. From these data, Fuerte was considered to be the cultivar with the best characteristics. Copyright © 2004 Society of Chemical Industry
Contents of hypericin and pseudohypericin in five commercial products of St John's wort (Hypericum perforatum)
Authors: Wang Zhao‐Jun , Lin Shih‐Mei , Hu Miao‐Lin 
Published: March 2004

AbstractHypericin and pseudohypericin are the two major dianthrones of St John's wort (SJW, Hypericum perforatum) that are reported to have antidepressant and antiviral effects. In this study we used methanol extracts of five commercial SJW products to determine the two congeners using a modified reverse phase HPLC method with gradient elution. One SJW product is specified by the manufacturer to contain 340 µg hypericin per tablet (170 mg extract), while the other four products are specified to contain 900 µg hypericin per tablet (300 mg); none of the products is claimed to contain pseudohypericin. Our results showed that the actual contents of hypericin in these products ranged from 1.7 to 38.5% of the claimed amounts. However, the amounts of pseudohypericin were in general much higher than those of hypericin. When hypericin and pseudohypericin were combined as total hypericin, the four products that supposedly contain 900 µg per tablet were found to contain 26, 484, 587 and 615 µg total hypericin per tablet, or 2.9, 53.8, 65.2 and 68.3% of the claimed hypericin contents respectively. The product which supposedly contains 340 µg hypericin per tablet was found to contain 388 µg total hypericin per tablet, or 114% of the claimed hypericin content. The relatively low hypericin contents measured in these products are not a result of losses during extraction, because the two congeners had high recoveries (93.7 and 94.3% for hypericin and pseudohypericin respectively) when added before methanolic extraction to an SJW product with known amounts of the two congeners. Thus our results show that the commercial SJW products vary greatly in their amounts of total hypericin and that pseudohypericin, rather than hypericin, is the major hypericin in these products. Copyright © 2004 Society of Chemical Industry
Protein and amino acids contents of Libyan dates at three stages of development
Authors: Ishurd Omar , Zahid Muhammad , Xiao Peng , Pan Yuanjiang 
Published: March 2004

AbstractThe protein and amino acid contents of three Libyan date varieties (Taasfirt, Bikrari and Khadhrai) at different stages of fruit development were determined. The protein concentration in all three varieties was highest at the green stage. Seventeen amino acids were detected and quantified; their concentrations (dry weight basis) were higher in Khadhrai and Bikrari than in Taasfirt. At the green stage the concentrations of glutamic acid, aspartic acid, lysine, leucine, alanine and serine were highest. At the yellow and ripe stages, glutamic acid, aspartic acid, lysine, leucine, proline and glycine were present in high concentrations. For most amino acids the concentrations were higher at the yellow stage than at the ripe stage. Copyright © 2004 Society of Chemical Industry
Nutritional evaluation of peas for ducks
Authors: Nyachoti Charles M , Onyango Edward M , Omogbenigun Olufemi F , Adeola Olayiwola 
Published: March 2004

AbstractThe nutritive value of four pea cultivars (AC Advantage, Carneval, CDC Mozart and Keoma) and soybean meal (SBM) was evaluated in a 102 h study with 48 male White Pekin ducks. All birds were tube‐fed 25 g of dextrose at 24 and 30 h after feed withdrawal, then 25 g of each feedstuff was tube‐fed to eight ducks at 48 and 54 h after feed withdrawal. Excreta were quantitatively collected during the next 54 h. Endogenous nitrogen, amino acids and energy per bird in the 54 h collection period were 1.06 ± 0.58 g, 0.047 ± 0.025 g and 0.098 ± 0.049 MJ respectively. There were differences (P < 0.05) in apparent amino acid digestibilities (AAAD) and true amino acid digestibilities (TAAD). On average, AAAD were 82.8, 82.0, 70.3, 82.4 and 77.7% and TAAD were 89.4, 89.2, 82.3, 89.5 and 85.3% for SBM, AC Advantage, Carneval, CDC Mozart and Keoma respectively. The nitrogen‐corrected apparent and true metabolisable energy values did not differ among the pea diets and were 13.36 ± 0.071 and 14.59 ± 0.071 MJ kg−1 respectively. Respective values for SBM were 12.16 ± 0.16 and 13.39 ± 0.16 MJ kg−1 and both were lower (P < 0.05) than in peas. Copyright © 2004 Society of Chemical Industry
Chemical composition of shell and flesh of three prawn samples from Lagos lagoon
Authors: Adeyeye E Ilesanmi , Adubiaro H Omolara 
Published: March 2004

AbstractThe protein, ash, fibre and individual mineral ion contents of three species of prawn taken from the Lagos lagoon were determined. The median liveweights of Macrobrachium vollenhovenii (Herklots), Palaemon species A (Powell) and Penaeus notialis were respectively, 25.52 g (shell + head 16.76 g; flesh 9.26 g), 3.15 g (shell + head 1.71 g; flesh 1.44 g) and 5.11 g (shell + head 2.14 g; flesh 2.96 g). All (shell + head) samples had high protein, ash and fibre contents but only the protein content was high in the flesh, which had low or undetectable quantities of fibre. The fat and carbohydrates contents were generally low. In M vollenhovenii the (shell + head) was a better source of Mg, Zn, Cu and K than the flesh, which was a better source of Ca, Ni, P, Fe, Co and Na. In P species A the (shell + head) was a better source of Ca, Mg, P, Cu, Co, Na and K than the flesh (higher in Zn and Ni). In P notialis the (shell + head) was the better source of Ca, Zn, P, Fe and Co and the flesh the better source of Mg, Ni, Fe, Na and K. Copyright © 2004 Society of Chemical Industry