bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nondestructive FTIR monitoring of leaf senescence and elicitin‐induced changes in plant leaves
Authors: Ivanova Diana G. , Singh Bal Ram 
Published: February 2003

AbstractThe applicability of the FTIR attenuated total reflectance technique for in situ monitoring of plant physiological processes such as leaf senescence and aging has been examined. Difference spectra obtained by subtracting the spectrum of the young plant leaf from that of the older one revealed positive bands at 1650–1500 cm−1, indicating a higher relative concentration of phenolics in the older leaves of both black cherry and sweet pepper bush leaves. Prolonged physiological stress of tobacco leaves exhibited a progressive time‐dependent increase of the absorbance at around 3475 cm−1, corresponding to hydroxyl functional groups. Absorption changes were also observed between 1650 and 1500 cm−1, which are likely to correspond to phenolics. The characteristic changes of the FTIR absorbance spectra resulting from physiological and induced aging were detected also as a response to treatment with a recombinant α‐elicitin, cinnamomin. This allowed the first quantification of the biological activity of a recombinant elicitin using a spectroscopic method. We suggest that FTIR spectroscopy provides important information about physiological events occurring in plant tissue in vivo, and it could be useful for the in situ characterization of the plant responsiveness to fungal toxins such as elicitins. © 2003 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 72: 79–85, 2003
1H‐NMR and 13C‐NMR lipid profiles of human renal tissues
Authors: Tugnoli V. , Bottura G. , Fini G. , Reggiani A. , Tinti A. , Trinchero A. , Tosi M. R. 
Published: February 2003

AbstractLipids from human renal tissues are studied by means of 1H‐ and 13C‐NMR spectroscopy. The total lipid fractions obtained from healthy kidneys, malignant renal cell carcinomas, and benign oncocytomas are characterized and analyzed to elucidate the main differences between the functional and neoplastic tissues. In all cases the lipid components are well identified. The healthy kidney is characterized by high amounts of triglycerides and the presence of cholesterol in its free form. On the contrary, renal cell carcinomas contain high amounts of cholesterol that are almost completely esterified as oleate, suggesting an intracellular localization of the cholesteryl esters synthesis. Cholesteryl esters are considered markers of renal cell carcinomas, thus supporting recent theories that these compounds play a leading role in cell proliferation. Oncocytomas are particularly rich in phosphatidylcholine and, analogous to the healthy kidney, are completely lacking in cholesteryl esters. Healthy kidneys and oncocytomas appear to have other similarities if compared with renal cell carcinomas: a very high fatty acyl/cholesterol ratio, the presence of dolichols, and a higher grade of unsaturation. The 13C data suggest a new method for the direct evaluation of the saturated/unsaturated fatty acyl ratio. © 2003 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 72: 86–95, 2003
Evidence that direct DNA uptake through cut shoots leads to genetic transformation of Solanum aviculare Forst
Authors: Gahan P. B. , Wyndaele R. , Mantell S. , Boggetti B. 
Published: February 2003

AbstractThe reporter genes GUS, NPTII and BAR, either separately or in combination, have been exploited to determine if DNA which can directly enter plants, circulate within the plant and enter nuclei, can also integrate into the genome in a manner which will permit gene expression. Feeding of either seed‐derived or adventitious cut shoots of Solanum aviculare with the GUS gene followed by rooting of the shoots and growing on, resulted in all tissues of the plant showing GUS activity as detected cytochemically. Southern blot analysis of plants derived from the adventitious shoots confirmed the presence of the reporter gene in roots. Reporter gene expression was observed also in the F1 generation. If GUS and NPTII or GUS, NPTII and BAR were fed together, then in each case it was possible to have both expression and Southern blot confirmation of each of the genes. There was a relatively high rate of transformation of approximately 5% of the fed stems across all experiments conducted during the present study. Copyright © 2002 John Wiley & Sons, Ltd.
On the role of chiral catalysts in the alkenyl zirconocene/zinc addition to aldehydes: A study of ligand loading and asymmetric amplification
Authors: Wipf Peter , Jayasuriya Nilukshi , Ribe Seth 
Published: February 2003

AbstractUnusual nonlinear asymmetric amplification and chiral ligand loading effects were discovered for the use of catalytic quantities of chiral aminoalcohols in the in situ hydrozirconation—transmetalation—aldehyde addition processes. While the stereochemically most efficient aminothiol ligands demonstrated mechanistically conventional reaction parameters in excellent agreement with Kagan's ML2 system, the asymmetric induction in the presence of a chiral aminoalcohol was found to vary greatly with loading and %ee of the ligand. Aminothiols remain the ligands of choice for the highly enantioselective formation of allylic alcohols and provide experimentally more predictable reaction variables. However, new, optimized conditions lead to a synthetically useful product %ee using the readily available and scalable aminoalcohol 2a. Chirality 15:208–212, 2003. © 2003 Wiley‐Liss, Inc.
Lipase regio‐ and stereoselectivities toward three enantiomeric pairs of didecanoyl‐deoxyamino‐O methyl glycerol: A kinetic study by the monomolecular film technique
Authors: Douchet Isabelle , de Haas Gerard , Verger Robert 
Published: February 2003

AbstractA kinetic study was carried out on the regio‐ and stereoselectivities of 12 lipases of animal and microbial origin. For this purpose, monomolecular films consisting of three pairs of enantiomers (didecanoyl‐deoxyamino‐O methyl glycerol, DDG) containing a single hydrolyzable decanoyl ester bond and two lipase‐resistant groups were spread at the air–water interface. Each of the lipases tested displayed a particular type of behavior, on the basis of which they were classified in two groups, depending on their ability to hydrolyze the sn‐2 position. From the qualitative point of view, the sn‐2 preference measured on triacylglycerides and DDG were in good agreement. The inductive chemical effect might explain why a greater level of hydrolytic activity was observed with the diglycerides than with DDG. With most of the lipases tested, it was observed that the enantiomeric pair having two distal acyl chains was more clearly differentiated stereochemically than the two homologous pairs with two adjacent acyl chains. This finding is consistent with the hypothesis that during the chiral recognition process two of the three attachment points may be the external (distal) hydrophobic chains, which is in line with the hypothesis of a tuning fork conformation of a triglyceride in the lipase active site. Chirality 15:220–226, 2003. © 2003 Wiley‐Liss, Inc.
Water‐borne, in situ crosslinked biomaterials from phase‐segregated precursors
Authors: Vernon Brent , Tirelli Nicola , Bächi Thomas , Haldimann David , Hubbell Jeffrey A. 
Published: February 2003

AbstractA novel process for the preparation of water‐borne biomaterials for hard tissue repair from injectable precursors is described, where the precursors form crosslinked materials in situ under physiological conditions. The precursors react by means of a Michael‐type addition reaction that makes use of addition donors such as pentaerythritol tetrakis 3′‐mercaptopropionate (QT) and addition acceptors such as poly(ethylene glycol) diacrylate 570 MW (PEGDA), pentaerythritol triacrylate (TA), and poly(propylene glycol) diacrylate 900 MW (PPODA). These crosslinked materials (at 75 wt% solid), prepared from water dispersions or reverse emulsions, showed ultimate strengths in compression of 1.8 ± 0.2 and 6.7 ± 0.5 MPa and ultimate deformations of 35 ± 2± and 37 ± 2%, respectively. Scanning electron microscopy (SEM) shows that the morphology of the precursors templated the morphology of the final materials. The current study indicates that it is possible to obtain injectable high‐modulus materials that have appropriate mechanical properties and gelation kinetics for tissue augmentation and stabilization applications such as mechanical stabilization of the intervertebral disc annulus. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 447–456, 2003
Bond strength, compositional, and structural properties of hydroxyapatite coating on Ti, ZrO2‐coated Ti, and TPS‐coated Ti substrate
Authors: Yang Yunzhi , Ong Joo L. 
Published: February 2003

AbstractThe effect of titanium plasma‐sprayed (TPS) and zirconia (ZrO2)‐coated titanium (Ti) substrates on the adhesive, compositional, and structural properties of plasma‐sprayed hydroxyapatite (HA) coatings were evaluated. X‐ray diffraction, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, surface roughness, and adhesive strength were used to characterize the coatings. Apatite‐type and α‐tricalcium phosphate phases were observed for all HA coatings. A structural change due to the absence of a 960 cm−1 peak during FTIR analysis was observed for all HA coatings. The coating surfaces appeared rough and melted, with surface roughness correlating to the size of the starting powder. No significant difference in the Ca/P ratio of HA on Ti and TPS‐coated Ti substrates was observed. However, the Ca/P ratio of HA on ZrO2‐coated Ti substrate was significantly increased. Interfaces between all coatings and substrates were observed to be dense and tightly bound, except for HA coatings on TPS‐coated Ti substrate interface. However, an intermediate TPS or ZrO2 layer between the HA and Ti substrate resulted in a lower adhesive strength as compared to HA on Ti substrate. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 509–516, 2003
Reserving resilient capacity for a single commodity with upper‐bound constraints
Authors: Brightwell G. , Oriolo G. , Shepherd F. B. 
Published: February 2003

AbstractContinuing research begun in a previous study [SIAM J Discr Math 14 (2001), 524–539], we investigate problems of reserving capacity in the arcs of a network, subject to the constraint that, on the failure of any one arc, there is enough reserved capacity on the remaining arcs to support a flow of value T from a source s to a destination t. We also impose upper bounds on the amount of capacity we may reserve on the arcs: This alters the nature of the problem. In the case where each arc has the same upper bound, we investigate the strategy of finding the minimum‐cost reservation that is itself an acyclic (s, t) flow: We show that such a reservation is easy to find, always has a simple form, and has a cost at most twice that of the optimal solution. In the case where each arc has its own upper bound, we explain why no such results can hold, but we do give an efficient algorithm for the case where we are asked for a reservation on a fixed set of arc‐disjoint paths. We consider the case where we are free to reserve on each arc as much capacity as we want but only in bundles of fixed size. © 2003 Wiley Periodicals, Inc.
Robustness properties of multivariate EWMA control charts
Authors: Testik Murat C. , Runger George C. , Borror Connie M. 
Published: February 2003

AbstractIn this paper, the robustness of the multivariate exponentially weighted moving average (MEWMA) control chart to non‐normal data is examined. Two non‐normal distributions of interest are the multivariate $t$ distribution and the multivariate gamma distribution. Recommendations for constructing MEWMA control charts when the normality assumption may be violated are provided. Copyright © 2002 John Wiley & Sons, Ltd.
Microscopic mechanism for C60 superconductivity
Authors: March Norman H. , Squire R. H. 
Published: February 2003

AbstractAfter a brief discussion of the four classes of superconducting materials, attention is focused on the fullerides. More critically, motivated by the work of Herzberg and Longuet‐Higgins (HLH), especially in the context of the Berry phase, and the topological superconducting model of Wiegmann we propose a microscopic model of C60 superconductivity. One key is the relationship of the HLH phase sign change of the wave function circling a degeneracy. The sign change is related to a topological quantity, a Chern number, which is a requirement specified for a topological superconductor, following Weigmann. Thus, it seems vibrational modes are topologically and coherently coupled to the electronic wave function. We establish a microscopic basis for topological superconductivity using Weigmann's generalization of Fröhlich's 1‐D model to two dimensions. This necessarily invokes the nonlinear sigma model and the addition of topological terms. We then reinterpret the work of Auerbach et al. and O'Brien by suggesting that vibrational analysis of C60 with Jahn–Teller distortions that produce a collective mode(s) that could be described by a soliton or, equivalently, a skyrmion model. The soliton (skyrmion) statistics are such that both fermions and bosons result depending on the number of electrons, n. Superconductivity is predicted for n = 3, and possibly 5 electrons, and n = 2 and 4 should be insulators. The strong coupling theory developed seems appropriate for describing a molecular superconductor. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Multidimensional analysis system for quantitative chemistry problems: Symbol, macro, micro, and process aspects
Authors: Dori Yehudit J. , Hameiri Mira 
Published: February 2003

AbstractThere is a consensus regarding the fact that students encounter difficulties in understanding scientific concepts, such as the particulate nature of matter, the mole, and the interpretation of chemical symbols. Researchers and practitioners have been looking for teaching methods to improve students' understanding of quantitative chemistry and their ability to solve related problems. This study describes the Multidimensional Analysis System (MAS), an approach to constructing, classifying, and analyzing quantitative chemistry problems. MAS enables classification based on complexity and transformation levels of a quantitative problem. We define three transformation levels: symbol ↔ macro, symbol ↔ micro, and symbol ↔ process. Applying this framework to teaching and research, we investigated the relationships between MAS‐classified chemistry problems and student achievement in solving these problems. The research population, 241 high school chemistry students, studied problem solving according to MAS for 9 weeks; the control group studied the same topic for the same duration in the traditional way. Student achievement was sorted by mathematics level and gender. We found that the success rate of the entire student population in solving these problems decreased as the problem difficulty increased. Experimental group students scored significantly higher than their control group peers. The improvement in student achievement was significantly dependent on the pretest score and the mathematics level, and independent of gender. Students who studied mathematics in the basic level benefited significantly more from MAS‐based teaching than their peers, whose mathematics level was advanced. Based on the research findings, we recommend applying the multidimensional analysis approach while teaching quantitative problems in chemistry. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 278–302, 2003
The Great War, the Russian Civil War, and the Invention of Big Science
Authors: Kojevnikov Alexei 
Published: February 2003

ArgumentThe revolutionary transformation in Russian science toward the Soviet model of research started even before the revolution of 1917. It was triggered by the crisis of World War I, in response to which Russian academics proposed radical changes in the goals and infrastructure of the country’s scientific effort. Their drafts envisioned the recognition of science as a profession separate from teaching, the creation of research institutes, and the turn toward practical, applied research linked to the military and industrial needs of the nation. The political revolution and especially the Bolshevik government that shared or appropriated many of the same views on science, helped these reforms materialize during the subsequent Civil War. By 1921, the foundation of a novel system of research and development became established, which in its most essential characteristics was similar to the U.S. later phenomenon known as “big science.”
Transfer of metformin into human milk
Authors: Gardiner Sharon J. , Kirkpatrick Carl M.J. , Begg Evan J. , Zhang Mei , Moore M.Peter , Saville Dorothy J. 
Published: February 2003

ObjectivesOur objectives were to determine the milk‐to‐plasma ratio of metformin in lactating mothers and to estimate infant exposure.MethodsTwo studies were performed. In study 1, 3 nursing mothers taking metformin were studied throughout a dosing interval at steady state. Blood samples were obtained from 2 suckling infants. In study 2, 5 healthy lactating women who volunteered to express milk after weaning were given metformin, 500 mg, at weaning and were studied for up to 72 hours. In both studies, areas under the plasma and milk concentration‐time curves were estimated, and the milk‐to‐plasma concentration ratio based on area under the concentration‐time curve analysis was derived. The infant dose was calculated by standard methods.ResultsIn study 1 the milk‐to‐plasma concentration ratios based on area under the concentration‐time curve analysis were 0.37, 0.50, and 0.71. The estimated “doses” of metformin that would be ingested by the breast‐fed infants were 0.18%, 0.20%, and 0.21% of the maternal doses, adjusted for weight. In the breast‐fed infants, no metformin was detected (n = 2) or adverse effects noted (n = 3). In study 2, the milk‐to‐plasma concentration ratio based on area under the concentration‐time curve analysis was unable to be calculated for 3 subjects because of the unexpected persistence of metformin in milk beyond the study period. For the 2 subjects studied for 72 hours, the milk‐to‐plasma concentration ratios based on area under the concentration‐time curve analysis were 0.27 and 0.47 and the infant doses were 0.11% and 0.25%. The concentration‐time profile for metformin in milk in all subjects was unexpectedly flat.ConclusionsMetformin appears to be “safe” during lactation because of low infant exposure. The unusual concentration‐time profile for metformin in milk suggests that the transfer of metformin into milk is not solely dependent on passive diffusion.Clinical Pharmacology & Therapeutics (2003) 73, 71–77; doi: 10.1067/mcp.2003.9
Fluorescence spectral properties of cyanine dye labeled DNA near metallic silver particles
Authors: Malicka Joanna , Gryczynski Ignacy , Maliwal Badri P. , Fang Jiyu , Lakowicz Joseph R. 
Published: February 2003

AbstractRecent studies have demonstrated that silver metallic particles can increase the quantum yield and decrease the lifetimes of nearby fluorophores. These studies are extended to double stranded DNA oligomers labeled with N,N′‐(dipropyl)‐tetramethylindocarbocyanine (Cy3) or N,N‐(dipropyl)‐tetramethylindodicarbocyanine (Cy5). The proximity to silver particles increases the apparent quantum yields and decreases the lifetimes of the double helical DNA 23‐mer labeled individually with Cy3 or Cy5. The decreased lifetimes are accompanied by apparently increased photostability of the labeled oligomers near silver particles. Because of spatial averaging across the sample these results are likely to significantly underestimate the effects of silver particles on labeled DNA localized at an optimal distance from the metallic surface. These results suggest that DNA arrays fabricated on substrates with silver particles can display increased sensitivity and photostability in the analysis of gene expression. © 2003 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 72: 96–104, 2003
Human cutaneous melanoma expresses a significant phosphate‐dependent glutaminase activity: A comparison with the surrounding skin of the same patient
Authors: Zacharias Darwin Pinheiro Machado , Lima Manuela Maria Ramos , Souza Alcione Lescano , de Abranches Oliveira Santos Ivan Dunshee , Enokiara Milvia , Michalany Nilceo , Curi Rui 
Published: February 2003

AbstractThe protein content and the activity and type of phosphate‐dependent glutaminase were determined in freshly pigmented lesions obtained from human melanoma and adjacent skin. Significant phosphate‐dependent glutaminase activity was found in both the melanoma and non‐pigmented adjacent skin areas. A comparison between the pigmented and adjacent skin areas suggests the occurrence of gradual metabolic changes that result in an increased protein content in the centre of the neoplasia. The presence of a kidney‐type glutaminase (Km of 2–5 mm) indicates a high sensitivity of the melanoma to variations in glutamine plasma levels (0.6 to 1 mm). These data lead us to postulate that glutamine supply is an important factor for melanoma cell proliferation, being a source of nitrogen for DNA and RNA synthesis. The intense neovascularization observed in melanoma ensures the oxygen supply that is required for glutamine oxidation. These findings support the proposition that glutamine is an important fuel for melanoma. Copyright © 2002 John Wiley & Sons, Ltd.
The role of activation in the effect of total sleep deprivation on depressed mood
Authors: Beutler L. E. , Cano M. C. , Miró E. , Buela‐Casal G. 
Published: February 2003

AbstractThe present investigation analyzes if the effect of Total Sleep Deprivation (TSD) on depressive mood in normal subjects is related to participants' activation levels. Reaction time (RT), subjective sleepiness, and depressive mood were assessed among 48 normal subjects who were subjected to 60 h of TSD. Subjects were divided into groups based on his/her depressive mood changes following TSD: subjects with worse response (n = 11), subjects with better response (n = 12), and intermediate group (n = 25). We sought to determine if RT and subjective sleepiness were related systematically to depressive mood changes following TSD. TSD produces a general reduction in activation (i.e., a monotonic increase in RT and subjective sleepiness) modulated by circadian oscillations. Baseline activation (RT) was confirmed partially as a predictor of participants' response to TSD. Subjects with high levels of activation (lower RTs at the baseline) experienced a better response (greater reductions in depressive mood) following TSD. There was no relationship between pre‐treatment subjective sleepiness levels and the TSD effect on depressive mood. The results partially support the role of the activation level as a differential moderator of TSD effects on depressive mood in normal subjects. © 2003 Wiley Periodicals, Inc. J Clin Psychol 59: 369–384, 2003.
Self‐administered treatments for depression: A review
Authors: McKendree‐Smith Nancy L. , Floyd Mark , Scogin Forrest R. 
Published: February 2003

AbstractAlthough there are numerous self‐help books for depression, relatively few have been empirically tested. However, those that have been used in clinical trials have fared well, with an average effect size roughly equivalent to the average effect size obtained in psychotherapy studies. Computer‐based treatments are being developed and appear promising as an alternative to bibliotherapy for those interested in self‐administered treatments. This article provides a summary of the depression bibliotherapy literature and discusses several remaining questions such as effectiveness versus efficacy, practice applications, ethics, and future research. © 2003 Wiley Periodicals, Inc. J Clin Psychol 59: 275–288, 2003.