bluuebunny/crossref_metadata_2025_split huggingface dataset:
The polyvinyl alcohol–bacterial cellulose system as a new nanocomposite for biomedical applications
Authors: Millon L. E. , Wan W. K. 
Published: May 2006

AbstractFinding materials suitable for soft tissue replacement is an important aspect for medical devices design and fabrication. There is a need to develop a material that will not only display similar mechanical properties as the tissue it is replacing, but also shows improved life span, biocompatibility, nonthrombogenic, and low degree of calcification. Polyvinyl alcohol (PVA) is a hydrophilic biocompatible polymer with various characteristics desired for biomedical applications. PVA can be transformed into a solid hydrogel with good mechanical properties by physical crosslinking, using freeze‐thaw cycles. Hydrophilic bacterial cellulose (BC) fibers of an average diameter of 50 nm are produced by the bacterium Acetobacter xylinum, using a fermentation process. They are used in combination with PVA to form biocompatible nanocomposites. The resulting nanocomposites possess a broad range of mechanical properties and can be made with mechanical properties similar to that of cardiovascular tissues, such as aorta and heart valve leaflets. The stress–strain properties for porcine aorta are matched by at least one type of PVA–BC nanocomposite in both the circumferential and the axial tissue directions. A PVA–BC nanocomposite with similar properties as heart valve tissue is also developed. Relaxation properties of all samples, which are important for cardiovascular applications, were also studied and found to relax at a faster rate and to a lower residual stress than the tissues they might replace. The new PVA–BC composite is a promising material for cardiovascular soft tissue replacement applications. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Real‐time monitoring of the setting reaction of brushite‐forming cement using isothermal differential scanning calorimetry
Authors: Hofmann M. P. , Nazhat S. N. , Gbureck U. , Barralet J. E. 
Published: May 2006

AbstractThe setting behavior of a brushite‐forming cement (β‐tricalcium phosphate/mono calcium monophosphate) was investigated using an indentation technique (the Gillmore needles method) and isothermal differential scanning calorimetry (DSC). The two objectives of the study were to investigate whether DSC could be used to real‐time monitor a fast‐setting calcium phosphate cement (CPC) and to determine if it is possible to correlate DSC results directly with conventional setting‐time measurements. Best‐fit linear correlation analysis revealed that both the initial and final setting time (Ti and Tf) measured by indentation were strongly correlated to the maximum heat flow measured with DSC. It seems therefore possible to predict the setting times, usually achieved with user dependent indentation methods, of this specific fast setting CPC on the basis of objective DSC measurements. The drawbacks of DSC, however, are its overall complexity and expense and the fact that only exothermal reactions can be investigated in comparison to the Gillmore needles method, furthermore, it is not possible to monitor the complete reaction as the first 2 or 3 min are lost due to sample preparation and apparatus set up. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Removal of noncollagenous components affects dentin bonding
Authors: Pereira P. N. R. , Bedran‐de‐Castro A. K. B. , Duarte W. R. , Yamauchi M. 
Published: May 2006

AbstractThe structural integrity of fibrillar type I collagen is critical for effective dentin bonding. Since most noncollagenous matrix components in dentin are closely associated with collagen, we hypothesized that they may also contribute to dentin bonding. To test this hypothesis, bovine dentin was acid‐etched, treated with chondroitinase ABC (C‐ABC), endo‐β‐galactosidase (Endo‐β), or trypsin. Controls were prepared in the same manner but without the enzymes. All control and experimental specimens were then bonded with One‐Step. Bond strength data were analyzed by one‐way ANOVA and Fisher's PLSD test (p < 0.05). When dentin was treated with C‐ABC or trypsin, bond strengths significantly decreased for the rewetted groups (p < 0.05). The treatment with Endo‐β showed no effects on bond strengths (p > 0.05). When the treated dentin surfaces were observed under SEM, the C‐ABC and trypsin treated groups revealed significant loss of collagen fibril architecture. The results indicate that chondroitin sulfate glycosaminoglycans and trypsin‐digestible noncollagenous proteins play roles in maintaining the open dimensions of the collagen fibril scaffold, which is essential for optimal dentin bonding. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Infiltration/evaporation‐induced shrinkage of demineralized dentin by solvated model adhesives
Authors: Becker Thomas D. , Agee Kelli A. , Joyce Anthony P. , Rueggeberg Frederick A. , Borke James L. , Waller Jennifer L. , Tay Franklin R. , Pashley David H. 
Published: May 2006

AbstractDuring dentin bonding, solvated adhesive comonomers are applied to water‐saturated decalcified dentin matrices. When alcohol‐solvated hydrophilic or hydrophobic methacrylate monomers are applied, they chemically remove water and cause matrix shrinkage during comonomer infiltration. Evaporation of solvent induces further shrinkage. The purpose of this work was to compare the shrinkage of water‐saturated dentin matrices infiltrated with ethanol‐ or methanol‐solvated 2‐hydroxyethyl methacrylate (HEMA), 2,2‐bis[4(2‐hydroxy‐3‐methacryloyloxy‐propyloxy)‐phenyl] propane (BisGMA), or triethyleneglycol dimethacrylate (TEGDMA) at 90/10, 70/30, 50/50, and 30/70 mass fraction % alcohol/monomer before and after evaporation of alcohol. Thin (ca 0.2 mm) disks of human mid‐coronal dentin were demineralized and placed in a well beneath the contact probe of a linear variable differential transformer (LVDT). The height of the matrix was measured before and after random application of one of the twelve alcohol/monomer mixtures. Matrix height was measured during infiltration and during solvent evaporation. Between trials, residual monomer was extracted using ethanol. These studies were repeated on specimens in which 100% alcohol was used to substitute for water in the matrix. Both studies revealed that matrices shrink 30–50% but that pretreatment of matrices with alcohol prevents BisGMA phase separations from occurring. Wet bonding with ethanol instead of water permits infiltration of relatively hydrophobic alcohol/monomers. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Consequences of work‐home segmentation or integration: a person‐environment fit perspective
Authors: Kreiner Glen E. 
Published: May 2006

AbstractThis study demonstrates how the interaction between an individual's work‐home segmentation preference and the perceived segmentation provided by the workplace affects work‐home conflict (WHC), stress, and job satisfaction. Using a person‐environment (P‐E) fit theoretical base and methodology, data from 325 employees in a wide variety of occupations and organizations illustrate significant fit effects on these outcomes. Results from polynomial regression and response surface methodology highlight important asymmetric effects found in these P‐E fit relationships. By demonstrating the asymmetric results of fit effects, the findings challenge previous research, which has typically advocated an integration of work and home in order to ameliorate role conflict and stress. Copyright © 2006 John Wiley & Sons, Ltd.
Temperature‐related trends in the vertical position of the summer upper tropospheric surface of maximum wind over the Northern Hemisphere
Authors: Strong Courtenay , Davis Robert E. 
Published: May 2006

AbstractThe surface of maximum wind (SMW) is used to examine spatial and temporal variability in the vertical position of jet streams and fast upper tropospheric wind maxima over the Northern Hemisphere (NH) in the NCEP/NCAR Reanalysis for summers 1958–2004. At a given observation time in a gridded data set, the SMW is defined as the surface passing through the fastest analyzed wind above each grid node, with a vertical search domain restricted to the upper troposphere and any tropospheric jet streams extending into the lower stratosphere. The 47‐year mean summer SMW generally resides below the tropopause, undulates in the tropics, and descends poleward in middle and high latitudes. Trends in the pressure of the summer SMW are primarily positive, exceed 30 hPa/decade at some locations, and are found over most of the tropics and subtropics for the period 1958–2004. The thermal wind relationship is used to establish links between the SMW pressure trends and temperature gradient changes in the upper troposphere. The changing temperature gradients are consistent with nonuniform tropospheric warming and are correlated with sea surface temperature (SST) variability related to El Niño and the Pacific Decadal Oscillation. Copyright © 2006 Royal Meteorological Society.
Thin plate smoothing spline interpolation of daily rainfall for New Zealand using a climatological rainfall surface
Authors: Tait Andrew , Henderson Roddy , Turner Richard , Zheng Xiaogu 
Published: May 2006

AbstractThis study presents a method for estimating daily rainfall on a 0.05° latitude/longitude grid covering all of New Zealand for the period 1960–2004 using a second order derivative trivariate thin plate smoothing spline spatial interpolation model. Use of a hand‐drawn (and subsequently digitised) mean annual rainfall surface as an independent variable in the interpolation is shown to reduce the interpolation error compared with using an elevation surface. This result is confirmed when long‐term average annual rainfall data, derived from the daily interpolations, are validated using long‐term river flow data. Copyright © 2006 Royal Meteorological Society
Pollen‐inferred palaeoclimate reconstructions in mountain areas: problems and perspectives
Authors: Ortu Elena , Brewer Simon , Peyron Odile 
Published: May 2006

AbstractTransfer functions are an efficient tool for the quantitative reconstruction of past climate from low to mid‐elevation pollen sites. However, the application of existing methods to high‐altitude pollen assemblages frequently leads to unrealistic results. In the aim of understanding the causes of these biases, the standard ‘best modern analogue’ method has been applied to two high‐altitude pollen sequences to provide quantitative climate estimates for the Lateglacial and Holocene periods. Both pollen sequences (Laghi dell'Orgials, 2130 m, SW aspect and Lago delle Fate, 2240 m, E aspect) are located in the subalpine belt, on opposing sides of the St. Anna di Vinadio Valley (Italian Maritime Alps). Different results were obtained from the two sequences. The largest differences occurred in palaeotemperature reconstruction, with notable differences in both the values and trends at each site. These biases may be attributed to: (1) a lack of high elevation ‘best modern analogues’ in the database of modern samples; (2) the problem of pollen taxa that have multiple climatic significance; (3) problems related to the complexity of mountainous ecosystems, such as the phenomenon of uphill transport of tree pollen by wind. Possible improvements to the reconstruction process are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Phptotophysics and kinetics of naphthopyran derivatives, part 4: Investigation of [3H]‐naphthopyran kinetics considered as an ABC(2k, 6ϕ) system yielding a monoexponential trace
Authors: Maafi M. , Brown R. G. 
Published: May 2006

AbstractThe elucidation of [3H]‐naphthopyran photochromic kinetics has been dealt with in this investigation by approximating the photocoloring traces as monoexponential. The experimental data have been analyzed, and 13 defining equations of the reactive dynamics have been established. These have been solved simultaneously as a system of nonlinear equations depending on the extinction coefficients and the six possible quantum yields of this ABC type system. The results of this new approach predict that both colored species are directly photochemically produced from the starting material. The most photochemically reactive photoisomer is the most thermally stable and is also the one characterized by the lowest extinction coefficient of the visible absorption band. The mechanism predicted for 3,3‐diphenyl‐3H‐naphtho[2,1‐b]pyran in toluene at 30°C obeys ABC(1k,6ϕ) kinetics. © 2006 Wiley Periodicals, Inc. J Chem Kinet 38: 431–438, 2006
Role of Star‐Like Hydroxylpropyl Lignin in Soy‐Protein Plastics
Authors: Wei Ming , Fan Lihong , Huang Jin , Chen Yun 
Published: May 2006

AbstractSummary: Star‐like hydroxypropyl lignin (HL) was compounded into soy protein isolated (SPI) to develop a potential biodegradable plastic with better mechanical performance than pure sheet‐SPI. The structure and properties of the composite materials were characterized by WAXD, DSC, SEM, TEM and tensile tests. The addition of just 2 wt.‐% HL resulted in tensile strength (σb) of 16.8 MPa, 2.3 times that of pure sheet‐SPI, with no accompanying decrease in elongation at break as a result of strong interaction and with good miscibility among components. As the HL content increased, the HL molecules could self‐aggregate as oblate supramolecular domains, while the stronger interactions between HL and glycerol resulted in the detaching of glycerol from the SPI matrix. It can be concluded that the insertion of HL as single molecules into the SPI matrix would provide materials with optimum mechanical properties. Compared with other lignin/SPI composites, the stretching chains on HL play a key role in the improvement of mechanical properties because of a stronger adhesion of HL onto the SPI matrix as well as the interpenetration of SPI into supramolecular HL domains.Schematic illustration of the supramolecular domain created by the aggregation of hydroxypropyl lignin, which can interpenetrate with soy protein isolate.imageSchematic illustration of the supramolecular domain created by the aggregation of hydroxypropyl lignin, which can interpenetrate with soy protein isolate.
Monitoring the mycotoxins in food and their biomarkers in the Czech Republic
Authors: Malir Frantisek , Ostry Vladimír , Grosse Yann , Roubal Tomas , Skarkova Jarmila , Ruprich Jiri 
Published: May 2006

AbstractTesting of the presence of toxigenic microfungi and mycotoxins in foodstuffs in the food chain is an important part of the food safety strategy in The Czech Republic. At the national level, control of their presence in the entire food chain is assured by Public Health Protection Agencies, by the Veterinary Administration and by the Czech Agriculture and Food Inspection Authority. This article summarizes surveillance activities of Public Health Protection Agencies and mycotoxins findings in dietary raw materials and foodstuffs from the 1990s to 2004 in the Czech Republic. At present, the health risk from the mycotoxins exposure from foodstuffs is assessed to be relatively low in the Czech Republic, especially as far as the foodstuffs of the Czech origin are concerned. It may result in late toxic effects (e. g., carcinogenic risk) following a single or repeated ingestion of low mycotoxins doses from foodstuffs. Nevertheless, the overall situation may change due to the globalization of the food market. In order to minimize the risk associated with mycotoxins and eliminate their impact on Czech public health, continuous monitoring of the presence of toxigenic moulds, mycotoxins, and their biomarkers is necessary, in conjunction with strict respect to European Union legislation.
Contamination of free‐range chicken eggs with dioxins and dioxin‐like polychlorinated biphenyls
Authors: Schoeters Greet , Hoogenboom Ron 
Published: May 2006

AbstractDioxins and dioxin‐like (DL) polychlorinated biphenyls (PCB) are persistent organic pollutants that enter the body mainly by food intake. A small margin exists between current exposure levels in the human population and the levels causing biological effects. Therefore, stringent control of concentrations of these contaminants in food and feed is needed. Eggs from free‐range chicken are increasingly becoming an important part of the diet. These eggs have a higher risk of being contaminated with increased levels of dioxins and DL‐PCB than barn or cage eggs. Ingestion of soil particles from environmentally contaminated areas may contribute to elevated dioxin levels in free‐range chicken eggs. Available data show that current soil levels of dioxins and DL‐PCB in residential and agricultural areas in Europe often appear to be too high to produce free‐range eggs with dioxin levels below the current limit values in the EU. On the other hand, polychlorinated dibenzo‐p‐dioxins/polychlorinated dibenzofurans concentrations in eggs from free‐range chicken are not necessarily above the limit values. Contamination levels in soil should be kept low and should be controlled in areas with free foraging chicken although all modifying factors that influence uptake of dioxins and PCB from the environment and transfer into eggs are yet not well understood.
A note on the power of Fisher's least significant difference procedure
Authors: Meier Ulrich 
Published: May 2006

AbstractFisher's least significant difference (LSD) procedure is a two‐step testing procedure for pairwise comparisons of several treatment groups. In the first step of the procedure, a global test is performed for the null hypothesis that the expected means of all treatment groups under study are equal. If this global null hypothesis can be rejected at the pre‐specified level of significance, then in the second step of the procedure, one is permitted in principle to perform all pairwise comparisons at the same level of significance (although in practice, not all of them may be of primary interest). Fisher's LSD procedure is known to preserve the experimentwise type I error rate at the nominal level of significance, if (and only if) the number of treatment groups is three. The procedure may therefore be applied to phase III clinical trials comparing two doses of an active treatment against placebo in the confirmatory sense (while in this case, no confirmatory comparison has to be performed between the two active treatment groups). The power properties of this approach are examined in the present paper. It is shown that the power of the first step global test – and therefore the power of the overall procedure – may be relevantly lower than the power of the pairwise comparison between the more‐favourable active dose group and placebo. Achieving a certain overall power for this comparison with Fisher's LSD procedure – irrespective of the effect size at the less‐favourable dose group – may require slightly larger treatment groups than sizing the study with respect to the simple Bonferroni alpha adjustment. Therefore if Fisher's LSD procedure is used to avoid an alpha adjustment for phase III clinical trials, the potential loss of power due to the first‐step global test should be considered at the planning stage. Copyright © 2006 John Wiley & Sons, Ltd.
Heat Sealing measurement by an innovative technique
Authors: Aithani Dinesh , Lockhart Hugh , Auras Rafael , Tanprasert Krittika 
Published: May 2006

AbstractTo obtain a proper heat seal is an important requirement in packaging, since seal failure is a more frequent cause of product deterioration than the package itself. Different kinds of seal, such as peelable or non‐peelable, can be obtained by changing the conditions under which a material is sealed. Therefore, identifying these conditions is very important. A new technique, the method for measuring temperature of melting surface (MTMS), was used to predict the strongest peelable seal on various packaging commercial films. The temperature of the seal interface was measured using a thermocouple. The time–temperature profile, which was obtained by means of a thermocouple, was electronically processed so as to obtain the derivatives of the profile. The inflection point, also called the fusion point, was located on these profiles. This inflection point is associated with the physical change of the state of the material being sealed. The inflection point analysis was done using two different methods: (a) the MTMS method, based on the second derivative of temperature data with time; (b) ‘Table Curve’ software, based on non‐linear regression. This technique was successfully used to evaluate widely used packaging films such as LDPE, HDPE, LLDPE and CPP. The inflection point for these films was identified and the seal strength was verified using a universal testing machine. This method appears to be applicable to design the strongest peelable heat seals for many packaging materials. It also seems to have promise as a method of process measurement and validation for heat seal processes. Copyright © 2006 John Wiley & Sons, Ltd.
An automated algorithm for determining respiratory rate by photoplethysmogram in children
Authors: Leonard Paul A. , Clifton David , Addison Paul S. , Watson James N. , Beattie Tom 
Published: May 2006

Abstract Background: We have developed an automated algorithm to allow the measurement of respiratory rate directly from the photoplethysmogram (pulse oximeter waveform). Aim: To test the algorithm's ability to determine respiratory rate in children. Methods: A convenience sample of patients attending a paediatric Accident and Emergency Department was monitored using a purpose‐built pulse oximeter and the photoplethysmogram (PPG) recorded. Respiration was also recorded by an observer activating a push‐button switch in synchronization with the child's breathing. The switch marker signals were processed to derive a manual respiratory rate that was compared with the wavelet‐based oximeter respiratory rate derived from the PPG signal. Results: Photoplethysmograms were obtained from 18 children aged 18 mo to 12 y, breathing spontaneously at rates of 17 to 27 breaths per minute. There was close correspondence between the wavelet‐based oximeter respiration rate and the manual respiratory rate, with the difference between them being less than one breath per minute in all children. Conclusion: Our automated algorithm allows the accurate determination of respiratory rate from photoplethysmograms of a heterogeneous group of children. We believe that our automated wavelet‐based signal‐processing techniques could soon be easily incorporated into current pulse oximetry technology.
Growth references for Turkish children aged 6 to 18 years
Authors: NEYZI OLCAY , FURMAN ANDRZEJ , BUNDAK RUVEYDE , GUNOZ HULYA , DARENDELILER FEYZA , BAS FIRDEVS 
Published: May 2006

Abstract Aim: To create up‐to‐date reference standards for Turkish children, and to compare these with growth standards for US children (CDC 2000 Growth Charts) and with previous local data. Subjects and Methods: Height and weight measurements of 1100 boys and 1020 girls were obtained by biannual visits to six schools located in relatively well‐off districts of Istanbul city. All children came from well‐to‐do families and all were healthy. All measurements were made by two trained technicians. The LMS method was used in the analyses. Results: Heights of the boys and girls in all age groups were close to the updated 2000 USA growth references and showed an increase from data on Turkish children born 30 y earlier. Weight values were high compared to reference data on US children and to the older data on Turkish children.Conclusion: These results indicate that height growth in Turkish school‐age children of high socio‐economic level conforms to the updated growth data on US children. The data also show a secular upward trend in Turkey. Weight‐for‐age values indicate an increase in obesity. The results also point to the value of collecting and evaluating local growth data periodically.