bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bis(2,4‐dinitrophenyl) phosphate hydrolysis mediated by lanthanide ions
Authors: Longhinotti Elisane , Domingos Josiel B. , da Silva Pedro L. F. , Szpoganicz Bruno , Nome Faruk 
Published: October 2004

AbstractThe kinetics of the hydrolysis of bis(2,4‐dinitrophenyl) phosphate (BDNPP) were studied in basic solutions in the presence of La3+, Sm3+, Tb3+ and Er3+. Bis‐Tris propane (BTP) buffer was used to stabilize the Ln3+ hydroxide complexes in solution. Two equivalents of the 2,4‐dinitrophenolate ion (DNP) were liberated for each equivalent of BDNPP and the reaction showed first‐order kinetics. Potentiometric titrations showed the formation of dinuclear complexes such as [Ln2(BTP)2(OH)n](6−n), with values of n varying as a function of pH, for all studied metals. Hence the catalytic effect depends on the formation of dinuclear lanthanide ion complexes with several hydroxo ligands. Copyright © 2004 John Wiley & Sons, Ltd.
A mechanistic viewpoint of the reaction between 1‐fluoro‐2,6‐dinitrobenzene and alicyclic amines in the ethyl acetate–chloroform system
Authors: Mancini P. M. , Fortunato G. G , Vottero L. R. 
Published: October 2004

AbstractA study was made of the influence of temperature on the reactions between 1‐fluoro‐2,6‐dinitrobenzene and each of the secondary amines pyrrolidine, piperidine and homopiperidine (hexahydro‐1H‐azepine), carried out in ethyl acetate–chloroform binary solvent mixtures. It involved the analysis of both global activation parameters and the corresponding Arrhenius plots from the kA values at three amine concentrations. These values were obtained by carrying out the reactions at 5, 15, 25, 40 and 50°C over the whole range of chloroform mole fraction. The analysis of Arrhenius lines allowed us to prove the existence of isokinetic relationships, which were used as a diagnostic tool in order to infer a changeover in the nature of the rate‐determining transition state as a function of solvent composition. The experimental evidence together with theoretical quantum mechanical calculations suggest that the reactions with the secondary amines explored carried out in pure ethyl acetate and ethyl acetate–chloroform solvent mixture at X = 0.1 and in some cases also at X = 0.3 proceed via the formation of a six‐membered orientated dipolar aggregate in which the specific base–general acid (SB–GA) mechanism may take place. The reactions carried out in the remaining solvent mixtures evolve towards the classical SB–GA mechanism. Copyright © 2004 John Wiley & Sons, Ltd.
DFT calculations on the allenyl Cope rearrangement of syn‐7‐allenylnorbornene: comparison with results obtained from CASSCF calculations
Authors: Duncan James A. , Spong Marie C. 
Published: October 2004

AbstractThe conformationally restricted allenyl Cope rearrangement of syn‐7‐allenylnorbornene (10) to racemic‐triene 11 was studied computationally using density functional theory (DFT) methods and the results were compared with those already calculated for this rearrangement at the (8,8)CASPT2/6–31G*//(8,8)CASSCF/6–31G* level of theory. The CASSCF level calculations had shown that the rearrangement involves two separate transition structures 12 and 13 that both lead to common diradical intermediate 14. These findings are consistent with the 90% stereoselectivity observed in the thermal Cope rearrangements of dimethyl allenylnorbornene derivatives racemic 7a and 7b. In this study, we found that CASSCF optimized structures 10–12 and 15 could be successfully re‐optimized at the UB3LYP/6–31G* level to structures of similar geometries and relative enthalpies. However, the CASSCF transition structure corresponding to 13 did not optimize to a UB3LYP version of 13, but rather to the UB3LYP‐optimized structure corresponding to transition structure 12. Despite taking several approaches, an optimized UB3LYP/6–31G* version of 13 was not found on the UB3LYP potential energy surface. Hence the UB3LYP results are not only at variance with the CASSCF results but also with the above mentioned experimental results. The 10→11 rearrangement was also studied using UBLYP and UBPW91 functionals in addition to UB3LYP and each of the three functionals predicted a different mechanism, none of them consistent with the experimental or CASSCF results. Copyright © 2004 John Wiley & Sons, Ltd.
Absolute determinations of the addition rate constants for the reactions of O(3P) atoms with halogenated propenes and butenes. A structure–activity relationship for the estimation of rate constants
Authors: Cometto Pablo M. , Teruel Mariano A. , Taccone Raúl A. , Lane Silvia I. 
Published: October 2004

AbstractThe kinetics of the reactions of O(3P) atoms with CF3CHCH2, CF3CClCCl2, CF3CFCClCF3 and CF3CClCClCF3 were studied at 298 K using a discharge flow tube system. This is the first absolute kinetic study of these reactions. The overall rate constants based on the measured afterglow reactions were (3.4±0.4) × 10−14, (3.3±0.6) × 10−14, (1.3±0.3) × 10−14 and (1.9±0.4) × 10−14 cm3 molecule−1 s−1, respectively. The experiments were carried out under pseudo‐first‐order conditions with [O(3P)]0 ≪ [alkene]0. The effect of substituent atoms or groups on the reactivity was analyzed. A simple method, using a structure–activity relationship based on the structure of the alkene, was applied for the first time to the reactions of O(3P) with haloalkenes. It is shown that this approach is useful in obtaining an initial estimate of unknown rate constants for reactions of O(3P) with alkenes. Copyright © 2004 John Wiley & Sons, Ltd.
Developments in the mechanism of photodegradation of triazine‐based pesticides
Authors: Canle L. M. , Fernández M. I. , Santaballa J. A. 
Published: October 2004

AbstractDevelopments in the mechanisms of the direct, photosensitized and photocatalyzed photodegradation and of photochemically generated hydroxyl radical‐based degradation of triazine‐based pesticides are reviewed. Recent results are accounted for: steady‐state irradiation photoproducts suggest the participation of both singlet and triplet excited states in the direct photodegradation of triazines, their concurrency being confirmed by luminescence studies. Both low‐lying excited states have been theoretically characterized. Laser flash photolysis and pulse radiolysis studies evidence the participation of short‐lived radical cations and radical anions, in addition to HO. adducts, in the mechanism of photodegradation. E° values were estimated for both the triazine (ca. ∼1.1 V vs NHE) and triazinyl radical cation (2.3 ± 0.1 V vs NHE) and also the pKa for the HO. adduct of triazines (ca. ∼11). Sub‐diffusion control rate constants were measured for the one‐electron oxidation of triazines by SO
and (UO)*, one‐electron reduction by e and HO. addition. Copyright © 2004 John Wiley & Sons, Ltd.
Molecular geometry as a source of chemical information. Part 2—An attempt to estimate the H‐bond strength: the case ofp‐nitrophenol complexes with bases
Authors: Krygowski Tadeusz Marek , Zachara Joanna Ewa , Szatylowicz Halina 
Published: October 2004

AbstractB3LYP/6–311+G** optimizations were carried out forp‐nitrophenol interacting with the flouride with the only constraints for O…F distance in the range 4.0–2.601 Å (for 19 computational data points) with an assumption of planarity of the system and linearity of OH…F. The monotonic dependences of interaction energies on C—O bond lengths led us to propose the C—O bond length as an approximate parameter to measure the H‐bond strength. Experimental geometries showed that the C—O bond length is very sensitive, and also that it is the most variable structural parameter in these complexes. Copyright © 2004 John Wiley & Sons, Ltd.
A complete parameterization of clf‐based input‐to‐state stabilizing control laws
Authors: Curtis J. W. , Beard Randal W. 
Published: October 2004

AbstractSontag's formula proves constructively that the existence of a control Lyapunov function implies asymptotic stabilizability. A similar result can be obtained for systems subject to unknown disturbances via input‐to‐state stabilizing control Lyapunov functions (ISS‐clfs) and the input‐to‐state analogue of Sontag's formula. The present paper provides a generalization of the ISS version of Sontag's formula by completely parameterizing all continuous ISS control laws that can be generated by a known ISS‐clf. When a simple inner‐product constraint is satisfied, this parameterization also conveniently describes a large family of ISS controls that solve the inverse‐optimal gain assignment problem, and it is proved that these controls possess Kalman‐type gain margins. Copyright © 2004 John Wiley & Sons, Ltd.
Model predictive control for constrained systems with uncertain state‐delays
Authors: Hu Xiao‐Bing , Chen Wen‐Hua 
Published: October 2004

AbstractThis paper presents a model predictive control (MPC) algorithm for a class of constrained linear systems with uncertain state‐delays. Based on a novel artificial Lyapunov function, a new stabilizing condition dependent of the upper bound of uncertain state‐delays is presented in an LMI (linear matrix inequality) form. The proposed MPC algorithm is developed by following the fashion of stability‐enforced scheme. The new algorithm is then extended to linear time varying (LTV) systems with multiple uncertain state‐delays. Numerical examples illustrate the effectiveness of the new algorithm. Copyright © 2004 John Wiley & Sons, Ltd.
Hormone receptor expression in interdigital glands of the Asian elephant (Elephas maximus)
Authors: Lamps Laura W. , Smoller Bruce R. , Goodwin Thomas E. , Rasmussen L.E.L. 
Published: October 2004

AbstractRecently, our group performed the first histologic, histochemical, and immunohistochemical analysis of eccrine‐type interdigital glands in the Asian elephant (Elephas maximus) (Lamps et al. [2001] Res Vet Sci 71:197–200). Since morphologically similar human eccrine glands express reproductive hormone receptors (including androgen, estrogen, and progesterone receptors), the purpose of the current study was to determine whether interdigital eccrine glands in the Asian elephant contain these same hormone receptors. Necropsy samples of interdigital areas from two adult Asian elephants (one male and one female) were obtained. Immunohistochemical staining was performed for estrogen, progesterone, and androgen receptor proteins. Immunoreactivity to all three receptor proteins was seen in a nuclear distribution in eccrine glands from both samples. This staining pattern is similar to that seen in human eccrine glands and tumors of eccrine derivation, although the significance of the receptor protein expression is unknown. The immunoreactivity of elephant interdigital glandular epithelium with monoclonal antibodies raised to human receptor proteins also suggests a high degree of phylogenetic conservation of these proteins between Asian elephants and humans. Despite detailed morphologic characterization, the function of these glands remains unclear. Further studies are needed to elucidate the function of these glands, the possible relationship between hormone receptor expression and circulating hormone levels, and the potential role of these glands in chemical communication in Asian elephants. Zoo Biol 23:463–469, 2004. © 2004 Wiley‐Liss, Inc.
Pregnancy detection and fetal monitoring via ultrasound in a giant panda (Ailuropoda melanoleuca)
Authors: Sutherland‐Smith Meg , Morris Patrick J. , Silverman Sam 
Published: October 2004

AbstractTransabdominal ultrasound was used to monitor the reproductive tract of a female giant panda (Ailuropoda melanoleuca) for three consecutive breeding seasons starting in 2001. Parturition did not occur in 2001 or 2002. In 2003, uterine enlargement was noted 109 days after natural mating occurred. A twin pregnancy was detected via transabdominal ultrasound 134 days following natural mating. Four subsequent ultrasound examinations, performed at 137, 138, 140, and 142 days postmating, documented fetal development. The female gave birth to one infant 150 days postmating. Zoo Biol 23:449–461, 2004. © 2004 Wiley‐Liss, Inc.
Effect of spatial crowding on aggressive behavior in a bonobo colony
Authors: Sannen Adinda , Elsacker Linda Van , Eens Marcel 
Published: October 2004

AbstractAccording to a previously proposed coping model (De Waal [1989] Zoo Biol. 1(suppl):141–148), gregarious primates will react to crowding by adjusting their behavior in order to limit the amount of aggression displayed. Depending on the duration of the crowding, this can be achieved by the use of different strategies. Chimpanzees (Pan troglodytes) react to a medium‐term duration of spatial crowding by an active tension‐reduction mechanism whereby allogrooming markedly increases while aggression rises only slightly. Under comparable circumstances, a similar increase in grooming is found in bonobos (Pan paniscus). However, to test the coping model for bonobos, data on aggressive behavior during crowding are indispensable. This study provides such information by comparing the aggressive repertoire of a well‐established bonobo colony during a crowded period in winter with those that occurred during an uncrowded control period in summer. Given that during winter the aggression rate differed between food and nonfood contexts, we accounted for a potential effect of food context on aggression. During the crowded period, a significantly higher total frequency of aggression was found than during the control period. However, this increase was small in relation to the reduction in space when compared to similar experiments in other species. Together with observations of increased grooming under crowded conditions, our data confirm the hypothesis that bonobos cope with the increase in tension created by crowding (medium‐term duration) by applying a tension‐reduction strategy. Our data further show that although not all aggressive behaviors appear to be influenced by a high‐density condition, bonobos do not specifically limit their aggressive behaviors to mild, nonprovocative aggressions in a crowded environment. Zoo Biol 23:383–395, 2004. © 2004 Wiley‐Liss, Inc.
Examination of the interrelationships of behavior, dominance status, and ovarian activity in captive Asian and African elephants
Authors: Freeman Elizabeth W. , Weiss Emily , Brown Janine L. 
Published: October 2004

AbstractOvarian inactivity has been identified in captive African (Loxodonta africana) and Asian (Elephas maximus) elephants and is thought to be mediated in part by social influences. Thus, a survey was conducted to determine how behavior and dominance status relate to each other and to ovarian cyclicity. For both Asian and African elephants, dominance status was positively correlated with relative size, age, temperament, disciplinary nature, and willingness to share novel objects. Relative size and temperament were also related to disciplinary nature toward herdmates. Behavior toward keepers was a good indicator of the willingness of elephants to follow commands, whereas sharing novel objects was positively correlated with object curiosity. Finally, dominance status, temperament, and disciplinary nature were all correlated with willingness to share. Comparisons of ovarian cyclicity status with behavior rankings were conducted only for African elephants because of the low number of noncycling Asian elephants surveyed. Overall, social status appeared to be the best predictor of ovarian activity in African elephants. Noncycling African elephant females ranked higher in the dominance hierarchy and gave more discipline to herdmates than cycling cohorts. It remains to be determined whether these are cause or effect relationships, but clearly it is important to understand how physical and social attributes impact physiological processes, such as reproduction. Captive management now needs to focus on optimizing social and environmental conditions to maximize reproductive potential in elephants. Zoo Biol 23:431–448, 2004. © 2004 Wiley‐Liss, Inc.
Do visual transects provide true population density estimates for deepwater fish?
Authors: Trenkel V.M. , Lorance P. , Mahévas S. 
Published: October 2004

Abstract
This study assesses the impact species ecology, fish reactions, and natural behaviour have on visual strip transect counts of deepwater fish carried out with an ROV (remotely operated vehicle). Two terraces and one canyon were visited on the continental slope of the Bay of Biscay. Species such as rabbit fish (Chimaeridae) and North Atlantic codling (Lepidion eques) appear to have avoided the ROV. The vertical distance off the bottom provided evidence that some individuals, in particular slickheads (Alepocephalidae) might have been missed by being above the ROV. GLM modelling showed the importance of depth, current speed, and relative surveying direction on transect counts. Natural and reaction behaviour of deep-sea fish will lead to variable and biased population density estimates.
Three-dimensional structure and avoidance behaviour of anchovy and common sardine schools in central southern Chile
Authors: Gerlotto F. , Castillo J. , Saavedra A. , Barbieri M.A. , Espejo M. , Cotel P. 
Published: October 2004

Abstract
We studied the avoidance behaviour and three-dimensional (3-D) structure of anchovy (Engraulis ringens) and common sardine (Strangomera bentincki) schools mixed in high concentrations in a coastal area of central southern Chile. Observations were carried out during an acoustic survey in January 2002 by means of a vertical echosounder and a multi-beam sonar. The sonar harvested around 900 series of 3-D school images, and 3000 2-D school images were collected with the echosounder. The results showed that all fish aggregations presented the same internal structure, but different global morphologies, from single small schools (with length three times the height) on the edges of the distribution to large dense layers (length more than seven times the height) in its centre. Observation of avoidance in the vertical and horizontal planes indicated that limited vertical diving occurred close to the ship (fish dive from the surface to the 5–10-m depth layer below the vessel), while no horizontal avoidance was observed.
Amyloid‐induced neurofibrillary tangle formation in Alzheimer's disease: insight from transgenic mouse and tissue‐culture models
Authors: Götz Jürgen , Schild Andreas , Hoerndli Fred , Pennanen Luis 
Published: October 2004

AbstractOf all forms of dementia, Alzheimer's disease is the most prevalent. It is histopathologically characterized by β‐amyloid‐containing plaques, tau‐containing neurofibrillary tangles, reduced synaptic density and neuronal loss in selected brain areas. For the rare familial forms of Alzheimer's disease, pathogenic mutations have been identified in both the gene encoding the precursor of the Aβ peptide, APP, itself and in the presenilin genes which encode part of the APP‐protease complex. For the more frequent sporadic forms of Alzheimer's disease, the pathogenic trigger has not been unambiguously identified. Whether Aβ is again the main cause remains to be heavily discussed. In a related disorder termed frontotemporal dementia, which is characterized by tangles in the absence of β‐amyloid deposition, mutations have been identified in tau which also lead to neurodegeneration and dementia.For Alzheimer's disease the existence of familial forms lead to the proposition of the amyloid cascade hypothesis, which claims that β‐amyloid causes or enhances the tangle pathology. In this review, we describe tau transgenic mouse models in which aspects of the tau‐associated pathology, including tangle formation, has been achieved. Moreover, tau transgenic mouse and tissue‐culture models were used to test the amyloid cascade hypothesis. In addition, we discuss alternative hypotheses to explain the sporadic forms. The animal and tissue‐culture models will provide insight into the underlying biochemical mechanisms of tau aggregation and nerve cell degeneration. These mechanisms may be partially shared between sporadic Alzheimer's disease, the familial forms and frontotemporal dementia. Eventually, Alzheimer's disease may be redefined based on biochemical events rather than phenotype.
Blood‐cell‐specific acetylcholinesterase splice variations under changing stimuli
Authors: Pick Marjorie , Flores‐Flores Cesar , Grisaru Dan , Shochat Susana , Deutsch Varda , Soreq Hermona 
Published: October 2004

AbstractDevelopmental and trauma‐induced mechanism(s) that modify inflammation and immune responses in blood cells were recently found to be regulated by acetylcholine. Here, we report corresponding blood cell‐specific changes in acetylcholinesterase splice variants. Plasmon resonance and flow cytometry using acetylcholinesterase variant‐specific antibody probes, revealed a progressive increase in myeloid cell fractions expressing the apoptosis‐related acetylcholinesterase‐S variant from newborns to adult controls and post‐delivery mothers. Hematopoietic cell fractions positive for the myeloproliferative acetylcholinesterase‐R variant, were similarly high in post‐partum blood, both intracellular and on the cell surface. Moreover, intracellular acetylcholinesterase‐S protein amounts as reflected by fluorescence intensity measurements remained unchanged in myeloid cells from post‐partum mothers as compared with matched controls. Unlike brain neurons, which over‐express intracellular acetylcholinesterase‐R under stress, lymphocytes from post‐partum mothers presented increased surface acetylcholinesterase‐S and pronounced decreases in both the expression and contents of surface acetylcholinesterase‐R. Peripheral stimuli‐induced modulations in acetylcholine regulation may hence reflect blood cell lineage‐dependent acetylcholinesterase splice variations.
Effect of the interpregnancy interval after an abortion on maternal and perinatal health in Latin America
Authors: Conde‐Agudelo A. , Belizán J.M. , Breman R. , Brockman S.C. , Rosas‐Bermudez A. 
Published: October 2004

AbstractObjectiveTo investigate whether the length of the interval between an abortion and the next pregnancy is associated with increased risks of adverse maternal and perinatal outcomes in Latin America.MethodRetrospective cross‐sectional study using information from 258,108 women delivering singleton infants and whose previous pregnancy resulted in abortion recorded in the Perinatal Information System database of the Latin American Centre for Perinatology and Human Development, Montevideo, Uruguay, between 1985 and 2002. Adjusted odds ratios were obtained through logistic regression analysis.ResultCompared with the post‐abortion interpregnancy intervals of 18 to 23 months, intervals shorter than 6 months were significantly associated with increased risks of maternal anemia, premature rupture of membranes, low birth weight, very low birth weight, preterm delivery, and very preterm delivery.ConclusionIn Latin America, post‐abortion interpregnancy intervals shorter than 6 months are independently associated with increased risks of adverse maternal and perinatal outcomes in the next pregnancy.DefinitionPost‐abortion interpregnancy interval (PAII): the time elapsed between the day of the abortion and the first day of the last menstrual period for the index pregnancy.
Sensory Nerves Transfers
Authors: BRUNELLI GIORGIO A. 
Published: October 2004

Various types of sensory nerve transfer in the hand are presented. They were all performed after brachial plexus injury to restore sensation, mainly to the adjacent borders of the thumb and index finger or to the ulnar aspect of the little finger. Twenty one cases were assessed. Their outcomes according to the Highet–Zachary system were: S2 in nine cases, S2 in four cases, S1 in four cases and S0 in four cases.