bluuebunny/crossref_metadata_2025_split huggingface dataset:
Do newborn rabbits learn the odor stimuli releasing nipple‐search behavior?
Authors: Hudson Robyn 
Published: January 2005

AbstractRabbit pups do not need to learn postnatally the pheromonal cues releasing nipple‐search behavior. Pups delivered by caesarian section were able to attach to nipples as quickly as normally delivered controls in their first encounter with a lactating doe (Experiment I), and pups hand raised to Day 5 without postnatal experience of the nipple‐search pheromone even showed an improvement in their reactivity to it similar to normally raised controls (Experiment II). However, 1‐day‐old pups could be conditioned during the first nursing episode to respond with nipple‐search behavior to artificial odors painted on the mother's ventrum (Experiment III). Finally, pups conditioned on Day 1 but subsequently raised by hand or normally nursed showed retention of the conditioned responsiveness when tested on Day 5 (Experiment IV). These experiments suggest that although rabbit pups are capable of rapidly associating odors with suckling, they do not appear to depend on this ability under normal nursing conditions.
Environmentally induced analgesia: Ontogeny of a nonopioid system
Authors: Knisely Janet S. , Hamm Robert J. 
Published: January 2005

AbstractPrevious research has demonstrated that exposure to 90 sec of hind paw shock activates an endogenous pain control system that involves cholinergic sites. The purpose of the present investigation was to examine the development of function of this nonopioid analgesic system. Research on the ontogeny of the cholinergic system suggests that this receptor system exhibits an extended period of postnatal development, with various neurochemical indexes reaching maturity between 30 to 50 days of age. Results revealed that exposure to hind paw shock produced very low levels of analgesia in 10‐ and 28‐day‐old rats. The analgesic response was more evident in 2‐month‐old rats, but the degree of hind paw schock‐induced analgesia was not at its maximum until 3 months of age. Systemic injection of naltrexone had no effect on the degree of analgesia induced by hind paw shock, while a systemic injection of scopolamine significantly attenuated the analgesia displayed by the 28‐day‐old and 2‐ and 3‐month‐old rats. Thus, the neurochemical indexes of cholinergic development overestimated the degree of functional maturity of the endogenous analgesia system activated by hind paw shock.
Acceleration and delay of puberty in female mice via urinary chemosignals: Age of the urine stimulus
Authors: Drickamer Lee C. 
Published: January 2005

AbstractFive experiments were conducted to test the effects of the age of urine on the acceleration and delay of puberty in female mice resulting from treatment with urinary chemosignals. The chemosignal in the urine of male mice that accelerates female puberty was not affected by remaining exposed to the air at room conditions for up to 7 days, or when dried in air and reconstituted with water. The chemosignal in the urine of grouped, female mice that delays puberty in females and the chemosignal present in the urine of pregnant and lactating female mice that accelerates female puberty were affected to varying degrees by exposure to room conditions; at 5‐to‐7 days exposure the urine samples lost their capacity to delay or accelerate sexual maturation. These results are in agreement with earlier work indicating that the male chemosignal is not volatile, whereas the substances in urine from grouped females and pregnant or lactating females are more volatile. The results also have implications for interpretations of how the urinary chemosignals may affect the population biology of house mice under natural conditions.
Vocal perception: Brain event‐related potentials in a chimpanzee
Authors: Berntson Gary G. , Boysen Sarah T. , Torello Michael W. 
Published: January 2005

AbstractWe describe the first brain event‐related potential (ERP) study of cognitive processes in the chimpanzee. In an extension of our studies on the ontogeny of vocal perception, ERP measures were obtained during the presentation of simple nonsignal stimuli as well as conspecific and human vocalizations. We initially confirmed findings from humans and monkeys of the appearance of a longlatency positivity in the ERP waveform to a rare stimulus in an oddball paradigm. This ERP component is reminiscent of the P3a reported in humans under similar (passive) experimental conditions. We further demonstrated that both conspecific and human vocal stimuli having affective significance also enhanced late positive components of the ERP. These late positive components displayed a predominant fronto–central distribution, with a maxima at Cz. Additionally, responses to adaptively significant vocal stimuli showed a right hemisphere laterality, whereas no significant laterality was observed with the rare stimulus in the oddball paradigm. Results document the feasibility of ERP measures in chimpanzees and their potential utility in the study of the ontogeny and phylogeny of vocal perception. © 1993 John Wiley & Sons, Inc.
Differential effects of SCH 23390 on immobility behaviors in developing rats
Authors: Van Hartesveldt Carol , Meyer Merle E. 
Published: January 2005

AbstractThe effects of a single injection of a dopamine D1 antagonist, SCH 23390, at doses of 0, 0.05, 0.1, and 0.2 mg/kg on three different kinds of immobility behavior were tested in rats of 10, 15, 20, and 30 days of age. Each animal was tested for the dorsal immobility response (DIR), vertical cling catalepsy, and bar catalepsy. A different pattern of results was found for each of the three immobility behaviors. SCH 23390 significantly increased the DIR at each age except 15 days; there was a progressive increase in effect from 10 to 20 to 30 days of age. At the lowest dose, drug‐induced bar catalepsy peaked at 15 days of age and declined at 20 and 30 days of age. The effect of SCH 23390 on vertical cling catalepsy increased with age, plateauing at 20 days. Thus, the developmental pattern of immobility responses to this dopamine D1 antagonist differs with each behavior measured. © 1993 John Wiley & Sons, Inc.
U50, 488 increases ultrasonic vocalizations in 3‐, 10‐, and 18‐day‐old rat pups in isolation and the home cage
Authors: Carden Susan E. , Davachi Lila , Hofer Myron A. 
Published: January 2005

AbstractSeparation‐induced calling in the young of many species can be modulated by the opioid system. Morphine reduces ultrasonic vocalizations (USVs) produced by isolated rat pups, an effect blocked by naltrexone. Central administration of the mu and delta opiate receptor agonists DAMGO and DPDPE reduce USV; kappa receptor agonist U50,488 increases them. We now find that peripheral U50,488 not only boosted calling rates in isolated 3‐, 10‐, and 18‐day‐old rat pups, but also induced calling in pups of these ages tested in the home cage with their littermates, where USVs are seldom heard in nature. U50,488 lowered rectal temperature, although temperature loss and USV were not correlated within drug treatment groups.© 1994 John Wiley & Sons, Inc.
Maternal sensitivity as an external organizer for biobehavioral regulation in infancy
Authors: Spanglar Gottfried , Schieche Michael , Ilg Ursula , Maier Ursula , Ackermann Claudia 
Published: January 2005

AbstractRecent findings from both animal and human research have clearly demonstrated connections between behavioral coping mechanisms and adrenocortical function. The aim of this study was to address the role of maternal sensitivity as an external organizer of psychobiological function in infants during the first year of life. Forty‐one infants and their mothers were observed during play at 3, 6, and 9 months of age. Age‐specific patterns of relation between maternal sensitivity and infant behavioral organization were found indicating contextual dependence of infant behavior at 3 months and experience‐related behavioral function at 9 months. An affect of maternal sensitivity on adrenocortical function during the free play was demonstrated at 3 and 6 months, because an increase in cortisol was most frequently observed in infants of highly insensitive mothers. The findings indicate the importance of maternal behavior for infant biobehavioral organization.©1994 John Wiley & Sons, Inc.
Plasma cortisol and vocalization responses of postweaning age guinea pigs to maternal and sibling separation: Evidence for filial attachment after weaning
Authors: Hennessy Michael B. , Nigh Carolee K. , Sims Millie L. , Long Stacey J. 
Published: January 2005

AbstractPostweaning guinea pigs housed with their mother and littermates since birth vocalized more and exhibited greater increases in plasma cortisol levels when placed for 1 hr into a novel test cage alone than they did when tested in the identical fashion with the mother present. These responses were apparent beyond 50 days of age, but had waned by 90 days of age. When tested with a familiar sibling cagemate, postweaning guinea pigs emitted fewer vocalizations than when tested alone but exhibited no less of an elevation of plasma cortisol levels. These results were obtained regardless of whether the subjects had been housed with mother and littermates from birth until the time of testing or with mother and littermates until weaning and then just the single sibling cagemate until the time of testing. The present findings closely approximate those seen in preweaning guinea pigs during tests of maternal and sibling separation, and indicate that guinea pigs can continue to exhibit a specific attachment to the mother beyond the time of weaning. © 1995 John Wiley & Sons, Inc.
Ontogeny of orientation and spatial learning on the radial maze in mices
Authors: Chapillon Pierre , Roullet Pascal , Lassalle Jean Michel 
Published: January 2005

AbstractThe development of the orientation capacities of C57BL/6 mice has been studied on the radial maze in several procedures allowed to dissociate the different types of cues used by the mouse for solving the task with two intersession delays (2 and 24 hr). The results of the first two studies show that performance is independent of intersession delay regardless of the age of the subject. Mice as early as 23 days old obtain good performances when they can develop an algorithmic strategy or when they dispose of both proximal and distal cues during learning. At 37 days of age, however, mice can efficiently solve the radial maze task with distal cues alone. However, in the third experiment, 23‐day‐old mice were able to use distal cues for orientation at the end of the learning session if, at the onset, they also had access to proximal cues. These results suggest that, on weaning, mice use several types of information for task performance and that, as they mature, they turn more often to distal cues for orientation. © 1995 John Wiley & Sons, Inc.
The structure of carbon trioxide
Authors: Pople John A. , Seeger Ute , Seeger Rolf , Schleyer Paul V. R. 
Published: January 2005

AbstractOpen (1) and cyclic (2) singlet forms of CO3 were investigated by means of ab initio calculations. At the highest level of theory employed, MP2/6‐31G* (which includes the effects of electron correlation), 2 was indicated to be much more stable than 1 and thermodynamically stable toward dissociation into CO2 and O(3P). The open form 1 has a long OO bond and can be regarded as a weak dative complex between CO2 and a singlet oxygen atom.
A comparative study of the structure and bonding of HOO, HOS, HSO, and HSS radicals by CNDO/2 and INDO methods
Authors: De B. R. , Sannigrahi A. B. 
Published: January 2005

AbstractEquilibrium geometries, force constants, barriers to linearity, charge distributions, dipole moments, and electron spin density of HOO, HOS, HSO, and HSS radicals are calculated by CNDO/2 and INDO methods using respectively the original and some recently introduced scheme of parametrization. Three sets of calculations, namely, CNDO/2(sp), CNDO/2(spd), and INDO, are performed, and the results are compared with the ab initio and experimental values, wherever available. A good agreement is obtained for geometry in the case of CNDO/2 (sp) and INDO calculations. The performance of CNDO/2 (spd) calculations in this regard is quite unreliable. The stretching force constants are considerably overestimated by all the methods, while the bending force constants are in reasonable agreement with the ab initio values. With respect to dipole moments, the CNDO/2 values are in better agreement with the ab initio results than the INDO values. In all the cases, the dipole moment vector directions are in complete disagreement with the ab initio predictions.
INDO‐Type calculations on the ground state and various ionic states of transition metal tricarbonyls
Authors: Böhm Michael C. , Gleiter Rolf 
Published: January 2005

AbstractBy means of the ΔSCF and transition operator (TO) methods based on a recently developed INDO extension to the first transition metal series, the first ionization potentials of benzene—chromium tricarbonyl (I), cyclopentadienyl manganese tricarbonyl (II), the iron—tricarbonyl complexes with trimethylenemethane (III), and cyclobutadiene (IV) have been calculated and compared with experimental data. It is shown that the electronic structure of I to IV can be rationalized by Hoffmann's fragment approach in both the ground state and the cationic hole states. Within the series I—IV there are remarkable energy differences in the ground state for MOs derived from the 1a1 and 1e orbitals of the M(CO)3 fragment. The observation that only one band is associated with the ionization events from MOs predominantly localized at the metal site is traced back to large relaxation effects. In the cationic hole states the split of the M(CO)3 fragment orbitals 1a1 and 1e is minute in all four compounds.
Basis set and correlation effects on computed lithium ion affinities of some oxygen and nitrogen bases
Authors: Del Bene Janet E. 
Published: January 2005

AbstractBasis set expansion and correlation effects on computed lithium cation affinities have been evaluated for the oxygen and nitrogen bases CH3OH, H2CO, CO, CH3NH2, CH2NH, and HCN. The presence of diffuse functions on nonhydrogen atoms is found to be the most important single enhancement of double‐ and triple‐split valence plus polarization basis sets. With the triple‐split basis, enhancement effects are nearly additive. Correlation usually decreases computed lithium ion affinities, with the second order Møller‐Plesset correlation term being the dominant term.
Theoretical studies of O2−:(H2O)n clusters
Authors: Curtiss Larry A. , Melendres Carlos A. , Reed Alan E. , Weinhold Frank 
Published: January 2005

AbstractThe interaction of superoxide ion O2− with up to four water molecules [O2−: (H2O)n, n = 1, 2, 4] has been investigated using ab initio molecular orbital theory. The binding energy of O2−: H2O is calculated to be −20.6 kcal/mol in good agreement with gas phase experimental data. At the MP3/6‐31G* level the O2−:H2O complex has a C2v structure with a double (cyclic) hydrogen bond between O2− and H2O. A Cs structure with a single hydrogen bond is only 0.7 kcal/mol less stable. Interaction of H2O with the doubly occupied π* orbital of O2− is preferred slightly over interaction with the singly occupied π* orbital. Natural bond orbital analysis suggests that both electrostatic and charge transfer interactions are important in anionic complexes. The charge transfer occurs predominantly in the O2− → H2O direction and is important in determining the relative stabilities of the different structures and states. Singly and doubly hydrogen‐bonded structures for the O2−: (H2O)2 and O2−: (H2O)4 clusters were found to be similar in stability and the increase in binding of the cluster becomes smaller as each additional water molecule is added to the cluster.
Ab initio studies of H2PXYH molecules (X, Y = O, S)
Authors: Boatz Jerry A. , Gordon Mark S. 
Published: January 2005

AbstractAb initio molecular orbital theory is applied to the study of PO and PS bonding in the hypervalent phosphinic (H2POOH), phosphinothioic (H2POSH), and phosphinodithioic (H2PSSH) acid molecules. Intramolecular proton exchange reactions are followed using the intrinsic reaction coordinate and Self‐Consistent‐Field energy localized orbitals. The PO and PS bonds are characterized via force constants, phosphorus d orbital populations, and localized orbitals and are best described as either normal single bonds or dative bonds augmented by π back donation from the oxygen or sulfur lone pairs. The anions of these acids are also investigated, and they are found to contain only dative bonds to sulfur and oxygen.
Conformational Properties of 3‐Phenylpiperidine and 3‐Phenylpyrrolidine Opioid Analgesics
Authors: Froimowitz Mark 
Published: January 2005

AbstractConformational energy calculations have been performed on 3‐phenylpiperidine and 3‐phenylpyrrolidine opioids using the MM2 method. Phenyl equatorial conformers were found to be preferred for 1,2,3‐trimethyl‐3‐phenylpiperidines while phenyl axial conformers were preferred for the 2‐demethyl derivative and 1‐methyl‐3‐isobutyl‐3‐phenylpyrrolidine. These conformational differences may account for differences in their structure‐activity relationships. The geometries of these compounds were superimposed onto a rigid phenyl‐axial opioid with the result that the more active antipodes of alpha‐2,3‐dimethyl‐3‐phenylpiperidine and 3‐isobutyl‐3‐phenylpyrrolidine antagonists were found to be a better fit. However, for the beta derivative, which has not yet been resolved, the opposite antipode was found to be a better fit though the orientation of NH bond was quite different. There is a good agreement between the computed molecular geometries and those observed by x‐ray crystallography.
Rapid Location of the Preferred Interaction Sites between Small Polar Molecules and Macromolecules. I. Binding of Water to the Component Units of Nucleic Acids
Authors: Neto Marçal De Oliveira 
Published: January 2005

AbstractAn approximate procedure for the rapid detection of favored sites for the location of bound water on macromolecules has been developed with the aid of accurate electrostatic energy calculations. The method also enables us to picture the lability of the bound water molecules around the substrate. As an application the method has been used to study the interaction surface between nucleic acid components and a water molecule.
Rapid Location of the Preferred Interaction Sites between Small Polar Molecules and Macromolecules. II. Binding of Water to a Model Segment of B‐DNA
Authors: Neto Marçal De Oliveira 
Published: January 2005

AbstractThe procedure developed in Part I of this series is applied to the homopolymeric sequences poly(dA) · poly(dT) and poly(dG) · poly(dC) on the double helical structure of B‐DNA. Some aspects of the base sequence influence on the polymer's attraction for water molecule are described. The results are used to discuss the general hydration features of those systems in relation to recent experimental studies of DNA single crystals.
Nonempirical Atom‐Atom Potentials for Main Components of Intermolecular Interaction Energy
Authors: Sokalski W. A. , Lowrey A. H. , Roszak S. , Lewchenko V. , Blaisdell J. , Hariharan P. C. , Kaufman Joyce J. 
Published: January 2005

AbstractAtom‐atom potentials representing separate contributions to the nonempirical interaction energy have been derived in the SCF decomposition scheme corrected for basis set superposition error by the counterpoise method. The nontransferable long‐range electrostatic multipole and classical induction terms have been evaluated directly from cumulative atomic multipole expansions, whereas the short‐range exchange, charge‐transfer, and electrostatic penetration contributions have been represented by simplified potentials of the form (β + δR−1) exp(−δR) fitted to the corresponding ab initio results for 336 dimer configurations formed by HF, H2O, NH3, CH4, CO, and CO2. The dominant anisotropic character of electrostatic multipole atom‐atom potentials and much more isotropic nature of the potentials representing short‐range terms is illustrated in the Appendix for head‐on interactions in CO ‥ OC and HF ‥ FH dimers.
A combined ab initio quantum mechanical and molecular mechanical method for carrying out simulations on complex molecular systems: Applications to the CH3Cl + Cl− exchange reaction and gas phase protonation of polyethers
Authors: Singh U. Chandra , Kollman Peter A. 
Published: January 2005

AbstractWe present an approach to couple ab initio quantum mechanical geometry optimiuzations with molecular mechanical optimizations, with the added capability to carry out molecular dynamics simulations of the systems to earch for new local minima. The approach is applied to the aqueous solution CH3Cl + Cl− exchange reaction and the gas phase protonation of polyethers.
Structural features of organic anions: 7‐Norbornadienyllithium
Authors: Lipkowitz Kenny , Burkett Anthony 
Published: January 2005

AbstractThe structure of 7‐norbornadienyllithium, a homoantiaromatic carbanion, is investigated with the semiempirical MNDO molecular orbital method. Alkene out‐of‐plane bendings persist even when the metal is fully solvated. The structural integrity of the monomer is retained in the dimer and solvated dimer; previously proposed dimers are inconsistent with lithium bonding and are not minimum energy structures on the MNDO hypersurface.
The role of d functions in ab initio calculations. II. The deformation densities of SO2, NO2, and their ions
Authors: Cruickshank D. W. J. , Eisenstein M. 
Published: January 2005

AbstractComparison of the optimized geometries and SCF energies for the series XO, XO2, XO, XO, with X = S,N shows that d(S) functions cause larger bond shortening and energy drop than d functions centered on first‐row atoms. This is further emphasized on comparing the separate effects of d(central atom) and d(O) functions for SO2 and NO, which are similar only for the first‐row molecule. The d(S) functions are also essential for proper prediction of the OSO angles. The deformation densities calculated for each series and the corresponding X–O shared populations, change as expected on adding electrons first into σ* then into π* molecular orbitals. In the regions around nuclei the deformation densities express the behavior of the atomic s and p valence orbitals or of their product inside their radial nodes. Introduction of d functions causes substantial polarization effects. For X = N these are mostly local except in the bonding regions where d(N) and d(O) functions are somewhat interchangeable. However, d(S) functions induce also unique changes in the deformation density near O. They cause π and π′ charge migration from O to S and a σ flow in the opposite direction. These effects are largest for the hypervalent species. The unique populations of the d(S) functions are much larger than those of d(N) and d(O) functions. The contribution of d(S) functions to bonding is related to the larger amplitude at small radii of the atomic 3d(S) orbital as compared with that of 3d(N). The difference in amplitudes is related to penetration effects. Diffuse p functions affect geometries and SCF energies of doubly, but not singly negative ions. However, they mostly describe the diffuse nonbonding clouds and do not affect bonding patterns.