bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum fluid dynamics of many‐electron systems in three‐dimensional space
Authors: Ghosh S. K. , Deb B. M.
Published: December 2004

In presence of external electric and magnetic fields, the Schrödinger equation for many‐electron systems is transformed into a continuity equation and an Euler‐type equation of motion in configuration space. Then, using the natural‐orbital Hamiltonian, as defined by Adams, the two fluid‐dynamical equations are derived in the three‐dimensional space. This generates a “classical” view of such quantum systems, corresponding to an MCSCF wave function: The many‐electron Schrödinger fluid consists of individual fluid components, each corresponding to a natural orbital and having its own charge density and current density. The local observables, viz., the net charge density and net current density, are obtained by merely summing over the natural orbitals, with the occupation numbers as weight factors; but, the net velocity field cannot be so obtained. Further, although each fluid component moves irrotationally in the absence of a magnetic field, the net velocity field is not irrotaional. The irrotational character of each velocity component is destroyed by rotation of the nuclear framework of the system while electron spin introduces an additional term, the spin magnetization moment, into each component current density. The physical significance of the fluid‐dynamical equations as well as their advantages and disadvantages are discussed.
Electronic structure and bonding of the pentasulfur hexanitride (S5N6) molecule
Authors: Trsic Milan , Wagstaff Kim , Laidlaw William G.
Published: December 2004

An ab initio version of the Hartree–Fock–Slater method is applied to obtain molecular orbitals and eigenvalues for S5N6. The electronic structure, bonding, stability, and electronic spectrum are discussed.
New derivation of (in)stability conditions for projected Hartree–Fock solutions
Authors: Karadakov P. , Castan̄o O.
Published: December 2004

A simple and straightforward derivation of (in)stability conditions for projected Hartree–Fock solutions is carried out and compared to the existing approaches to the problem.
Diamagnetic shielding constants of first‐row atoms: Studies with a piecewise exponentially decaying electron density function
Authors: Kaur Livjeet
Published: December 2004

The piecewise exponentially decaying electron density model of Wang and Parr is used to calculate the diagmagnetic shielding constants of first‐row atoms. Numerical results are presented for all first‐row atoms and comparisons are made with the results obtained from the one‐zone (i.e., single exponential) model. Results obtained from the two‐zone (i.e., piecewise exponential) model are in better agreement with the Hartree–Fock results.
Spontaneous symmetry breaking in large scale nervous activity
Authors: Cowan Jack D.
Published: December 2004

A theory is outlined of the nature and origin of drug‐induced visual hallucination patterns. It is shown that such patterns correspond to blobs or stripes of visual neo‐cortical activity. A neuronal circuit is described that generates such patterns whenever its homogeneous resting state becomes unstable. Such a process is shown to be an example of spontaneous symmetry‐breaking, similar to that occurring in electro‐weak interactions, and in fluid convection. It is suggested that the neuronal instability is produced by the action of hallucinogens on monoamine secreting brain‐stem neurons.
Ab initio calculation of magnetic susceptibilities and screening constants using gauge invariant Gaussian orbitals
Authors: Boucekkine‐Yaker G. , Boucekkine A. , Zaucer M. , Berthier G.
Published: December 2004

The magnetic susceptibility and screening constant tensors are calculated using an ab initio finite perturbation SCF method, with gauge invariant Gaussian orbitals. The isoelectronic BH BeH−, and CH+ molecules have been studied. The calculated values for BH are relatively different from those obtained by other methods. The CH+ molecule seems to exhibit a stronger temperature independent paramagnetism than BH, while the BeH− molecule would be diamagnetic. The screening constants of the heavy atom of these molecules present a similar variation.
Force in SCF Theories. First and second derivatives of the potential energy hypersurface of chemical reaction systems
Authors: Nakatsuji H. , Hada M. , Kanda K. , Yonezawa T.
Published: December 2004

Accurate Hellmann–Feynman force method for the first and second derivatives of energy has been applied to the studies of the chemical reaction systems. We have studied (1) the electronic origins of the structure‐reactivity correlations in the reactions CH3 + H → CH4 and CH3 + CH3 → C2H6 and (2) the geometries and force constants in the reaction intermediate and the transition state of the reactions F− + HF → [FHF]− → FH + F− and H− + CH4 → CH4 + H−, respectively. An intuitive simplicity of the underlying concepts of the first and second derivatives of the present approach is shown in the analysis.
Finite‐field calculations of molecular polarizabilities using field‐induced polarization functions. II. Second‐ and third‐order perturbation correlation corrections to the coupled Hartree–Fock polarizability of HF
Authors: Mukherjee Prasanta K. , Minato Tsutomu , Chong Delano P.
Published: December 2004

Correlation corrections to coupled Hartree–Fock (CHF) static dipole polarizabilities and dipole moment of the HF molecule are calculated using third‐order Rayleigh–Schrödinger perturbation theory with Møller–Plesset partitioning (RSMP) in a finite‐field procedure. Computations are also made for the dipole moment and polarizability derivatives at the equilibrium internuclear separation. Three different basis sets using contracted Gaussian orbitals augmented by field‐induced diffuse polarization functions have been employed to investigate the nature of variation of the properties under study, and the importance of field‐induced diffuse polarization functions is discussed. [2/1] Padé approximants are used to accelerate the convergence of the properties. The correlated dipole moment and polarizability values are in excellent agreement with the existing theoretical and experimental values. The dipole moment derivative is in perfect agreement with the existing correlated value. However, the polarizability derivatives at SCF and correlated levels differ appreciably from the existing SCF values and represent as improvement.
Symmetry broken self‐consistent field approximation for coupled oscillators
Authors: Lefebvre R.
Published: December 2004

A self‐consistent field approximation allowing for a change of coordinates is applied to a model of two coupled oscillators considered by Davis and Heller [J. Chem. Phys. 75, 246 (1981)]. The model accounts well for the unsymmetrical nonstationary states involved in the quantum dynamical tunneling phenomenon.
Translation factors in atomic collisions
Authors: Piacentini R. D.
Published: December 2004

Different methods proposed for taking into account the momentum transfer in electron capture collisions are reviewed. Exact one‐electron two‐Coulomb‐center molecular wave functions are considered for studying fully stripped ions–hydrogen atom collisions. The semiclassical impact parameter treatment is used, since it is well adapted to the keV/amu energy range investigated.
Heats of atomization of some conjugated molecules containing nitrogen or oxygen by a novel semiempirical method
Authors: Živković Tomislav P.
Published: December 2004

Heats of atomization for a range of conjugated molecules containing nitrogen or oxygen are calculated by a semiempirical method that combines some features of both the MO and VB theories. The π ground state of each conjugated molecule is represented as a linear combination of Kekulé structures. Unlike in the VB theory, each Kekulé structure is a determinant containing bond orbitals. Here experimental heats of atomization are reproduced approximately as well as by the more sophisticated SCF–MO approach. The use of this method is, however, much simpler since it amounts to a single diagonalization of a matrix of the order equal to the number of Kekulé structures only.
Unusually large electrostatic field effect of the buried aspartate in serine proteinases: Source of catalytic power
Authors: Náray‐Szabó Gábor
Published: December 2004

Calculating the electrostatic potential around the Ser–His–Asp catalytic triad in serine proteinases the very important substituent effect of the buried aspartate is revealed. It is found that the strong Coulomb field of this distant but charged side chain considerably enhances the nucleophilicity of the active serine hydroxyl group. The interpretation of the vital importance of aspartate may replace the “charge–relay” hypothesis which seems to be disproved in the light of recent experiments.
Electronic structure of small copper clusters
Authors: Miyoshi Eisaku , Tatewaki Hiroshi , Nakamura Takashi
Published: December 2004

An all‐electron ab initio LCAO‐MO SCF calculation has been carried out for the electronic structure of small copper clusters (Cun, n = 2–6). The basis set superposition error occurring in the calculation, the equilibrium configuration of Cu3, the bond energy in the clusters, and the localized d‐hole in excited and ionized states of Cu2 are closely examined.
Energy‐band structure and charge distribution for BaC6
Authors: Holzwarth N. A. W. , Divincenzo D. P. , Tatar R. C. , Rabii S.
Published: December 2004

An ab initio self‐consistent calculation has been carried out for the electronic properties of BaC6. Energy bands and charge densities are presented for BaC6 and compared with those of LiC6. The results show that the band originating from Ba states has a mixture of s and d character and the d component hybridizes appreciably with the π bands of graphite. The Fermi level intersects this band as well as the graphite π bands, giving rise to a complicated Fermi surface with several types of carriers. Depending on the type of volumetric partitioning, the charge transfer from Ba to graphite layers is determined to be between 0.7 and 1.0 electron per Ba atom. The calculated results are consistent with available transport and optical measurements.
Perturbation theoretical investigation of electron correlation effects in infinite metallic and semiconducting polymers
Authors: Suhai Sándor
Published: December 2004

Møller–Plesset‐type perturbation theory is applied to calculate electron correlation effects in infinite, periodic, metallic, and semiconducting polymers. Different possible choices of the zeroth‐order Hamiltonian (symmetry adapted Hartree–Fock, spin‐, and charge‐density waves), the influence of the size of the atomic basis sets, lattice and conduction band sums are investigated. In the case of semiconducting systems a very efficient version of the method using optimally localized Wannier functions has been worked out. Applications include model calculations for infinite atomic hydrogen chains, the investigation of the role of correlation effects in the bond alternation and metal‐insulator phase transition in polyene, different one‐and many‐particle effects contributing to the single‐particle gap in polyene, and the calculation of correlated quasiparticle band structures using the electronic polaron model.
Electrostatics and gating of excitable membranes
Authors: Lundström Ingemar , Nylander Claes
Published: December 2004

Two electrostatic models for ion permeability of membranes are considered. In the first model ions pass hydrated through the membrane and in the second model ions pass unhydrated through a channel lined with polar groups. In both cases it is found that it is not necessary to assume a high macroscopic dielectric constant of the membrane or channel to provide a low enough potential energy of the ion in the membrane. Gating of excitable membranes is considered a special case of electrostatic interaction in membranes. A simple physical model which fits with Hodgkin and Huxley's empirical relation is derived. Finally, we have speculated upon other membrane bound biological phenomena where electrostatic effects may be important.
INDO Studies on the electronic structure of lanthanoid compounds
Authors: Le‐min Li , Jing‐Qing Ren , Guang‐Xian Xu , Xiu‐Zhen Wang
Published: December 2004

Expressions needed in INDO calculations for compounds containing 4f elements were derived and an INDO program suitable for lanthanoid compounds was written and tested. Electronic structure of LnF3 and paramagnetic shift of NMR spectra of LnF were studied.
Electronic structure of model chlorophyll systems
Authors: Edwards W. Daniel , Zerner Michael C.
Published: December 2004

An examination of the ground and excited states of magnesium porphine and pheoporphine and their positive and negative ions using the intermediate neglect of differential overlap/spectroscopic method is reported. It is found that rather large changes in the Mg out‐of‐plane coordinate can be attained at very little cost in energy. These geometric changes alone can be used to explain the large range of spectroscopic shifts observed in the visible band of chlorophyll that are site dependent. These calculations also show a porphyrin to Mg charge transfer excitation at about 20,000 cm−1, which, if populated and allowed to relax, becomes the lowest excited singlet. This suggests that the initial photochemical event in photosynthesis may be excitation to the visible Q band followed by internal conversion to the charge transfer state accompanied by movement of the Mg atom out of the plane of the ring. This movement could result in intermolecular charge transfer, and relaxation of the Mg atom back to the plane of the ring. The nature of the positive and negative ions of these model chlorophylls is discussed in light of their role as the electron donor and their potential role as initial electron acceptor in photosynthesis.
Irreversibility, time, and fluctuations in quantum statistical theory of dissipative molecular systems. II. Application to fluorescence spectroscopy
Authors: Chatzidimitriou‐Dreismann C. A.
Published: December 2004

Some basic concepts of the Prigogine quantum statistical theory of irreversible processes are discussed in connection with a previous paper by Chatzidimitriou‐Dreismann and Lippert. The removal of the “dual role” that the Hamiltonian plays within conventional quantum theory corresponds to the introduction of a star‐unitary operator 𝒯 called “intrinsic time.” The formalism of the previous paper is extended to systems that interact with external fields. A formal specification of 𝒯, furthermore, follows from the Lt invariance of the basic equations of motion and its connection with the intrinsic time. As an application to fluorescence spectroscopy, a photon counting experiment is presented. It allows us to detect certain predicted “dynamical” fluctuations in emission spectra. Some current experimental results are reported concerning the resolution of the broad fluorescence band of fluoranthene (dissolved in ethanol) through detection of the underlying finer vibrational structure.
Evidence for coherent excitation in biological systems
Authors: Fröhlich H.
Published: December 2004

From theoretical considerations, three types of coherent excitations of biological systems have been suggested: (i) vibrations of membranes and of proteins with frequencies above 109 Hz; (ii) near static excitation of a highly polar metastable state; and (iii) low frequency periodic enzyme reactions. Recent experimental evidence is discussed.
Democratising the Family and the State? The Case of Family Group Conferences in Child Welfare
Authors: HOLLAND SALLY , SCOURFIELD JONATHAN , O'NEILL SEAN , PITHOUSE ANDREW
Published: December 2004

This article discusses the potential of family group conferences to act as a liberating intervention for families traditionally controlled by the state welfare system. Family group conferences are interventions designed to remove control of decision making from professionals and allow family groups to make decisions about the welfare of one or more of their members. Using data from a qualitative evaluation of family group conferences in Wales, this article examines ‘imposed empowerment’ and social control, and the feasibility of treating ‘the family’ as a unit for state intervention. The authors propose that the family group conference approach not only has the potential to shift the balance of power between the state and client families, but that it may have the potential to democratise decision making within families. However, it is also noted that such interventions can be seen to be maintaining social control through subtle and possibly unintentional means. The article engages with sociological research and theory on democracy in the family.
CD44 variant isoform v10 is expressed on tumor‐infiltrating lymphocytes and mediates hyaluronan‐independent heterotypic cell–cell adhesion to melanoma cells
Authors: Weimann T. K. , Wagner C. , Goos M. , Wagner S. N.
Published: December 2004

Abstract: CD44 is a family of cell‐surface receptors on human lymphocytes that act as co‐stimulatory molecules leading to the induction of effector functions in T cells. We have analyzed primary cutaneous malignant melanomas with clinical and histologic signs of tumor regression using immunohistochemistry and observed the predominant expression of the CD44 variant isoform v10 on CD3 CD4/CD8 co‐expressing tumor‐infiltrating lymphocytes (TIL). We further analyzed the role of CD44v10 in adhesion of lymphocytes to human melanoma cells. In contrast to CD44– lymphatic cells, CD44v10+ lymphatic cells strongly bound to cultured human melanoma cells and to frozen tissue samples of melanomas. Antibody blocking studies revealed a hyaluronan‐, integrin‐, and selectin‐independent pathway of adhesion. Furthermore, CD44v10+ lymphatic cells exhibited significantly higher invasiveness in three‐dimensional collagen matrices as compared with CD44H+ and CD44‐negative lymphocytes. These results indicate that expression of CD44v10 on TIL may mediate adhesion to melanoma cells and result in gain of novel invasive properties.
Plasticity of hair follicle dermal cells in wound healing and induction
Authors: Gharzi A. , Reynolds A. J. , Jahoda C. A. B.
Published: December 2004

Abstract: The capacity of adult hair follicle dermal cells to participate in new follicle induction and regeneration, and to elicit responses from diverse epithelial partners, demonstrates a level of developmental promiscuity and influence far exceeding that of interfollicular fibroblasts. We have recently suggested that adult follicle dermal cells have extensive stem or progenitor cell activities, including an important role in skin dermal wound healing. Given that up to now tissue engineered skin equivalents have several deficiencies, including the absence of hair follicles, we investigated the capacity of follicle dermal cells to be incorporated into skin wounds; to form hair follicles in wound environments; and to create a hair follicle‐derived skin equivalent. In our study, we implanted rat follicle dermal cells labelled with a vital dye into ear and body skin wounds. We found that they were incorporated into the new dermis in a manner similar to skin fibroblasts, but that lower follicle dermal sheath also assimilated into hair follicles. Using different combinations of follicle dermal cells and outer root sheath epithelial cells in punch biopsy wounds, we showed that new hair follicles were formed only with the inclusion of intact dermal papillae. Finally by combining follicle dermal sheath and outer root sheath cells in organotypic chambers, we created a skin equivalent with characteristic dermal and epidermal architecture and a normal basement membrane – the first skin to be produced entirely from hair follicle cells. These data support the hypothesis that follicle dermal cells may be important in wound healing and demonstrate their potential usefulness in human skin equivalents and skin substitutes. While we have made progress towards producing skin equivalents that contain follicles, we suggest that the failure of cultured dermal papilla cells to induce follicle formation in wounds illustrates the complex role the follicle dermis may play in skin. We believe that it demonstrates a genuine dichotomy of activity for follicle cells within skin.
Keratinocyte unresponsiveness towards interleukin‐10: lack of specific binding due to deficient IL‐10 receptor 1 expression
Authors: Seifert Martina , Gruenberg Beate H. , Sabat Robert , Donner Peter , Gruetz Gerald , Volk Hans‐Dieter , Wolk Kerstin , Asadullah Khusru
Published: December 2004

Abstract: Whereas the effects of interleukin (IL)‐10 on several epithelial cell types are well established the capability of IL‐10 to target keratinocytes (KC) is still a matter of debate. This, however, is of considerable importance, as IL‐10 is a major anti‐inflammatory, immunosuppressive cytokine with impact on the cutaneous homeostasis. Recently, IL‐10 therapy has been proven to be clinically effective in psoriasis. Response to therapy is associated with normalization of typical parameters of keratinocyte pathology, but it is unclear whether this results from direct or indirect (secondary) effects. The purpose of the present study was to further investigate direct effects of IL‐10 on keratinocytes and to address the reason for potential IL‐10 unresponsiveness using keratinocytes such as the cell line HaCaT as well as primary foreskin keratinocytes. Using real time RT‐PCR we demonstrated that IL‐10 is neither able to induce its typical early gene product suppressor of cytokine signalling (SOCS) 3 nor to modulate the interferone (IFN)‐γ‐induced expression of SOCS 1 and 3. Although flow cytometric analyses showed binding of biotin labelled IL‐10 to HaCaT cells, blocking experiments indicated that this resulted from unspecific binding. Moreover, scatchard plot analyses excluded specific binding to primary KC and HaCaT cells. Finally, real time mRNA analyses and Western blot experiments demonstrated that the absence of any specific binding results from the absence of clear IL‐10R1 (alpha chain) expression, whereas the IL‐10R2 (beta chain) is strongly expressed. Our data indicates that IL‐10 unresponsiveness of keratinocytes could be explained by the lacking of functional IL‐10 receptor expression and suggest that any IL‐10 effects on these cells observed are indirectly mediated.
Characteristics of tooth wear in relation to different nutritional patterns including contemporary and medieval subjects
Authors: Ganss Carolina , Klimek Joachim , Borkowski Nina
Published: December 2004

The present study sought to evaluate the characteristics of tooth wear in subjects with an acidic diet in relation to subjects with substantially different nutritional patterns. The evaluation included medieval skulls (group 1, n=102, abrasive nutrition), study models of individuals living on an acidic diet (group 2, n=100) and randomly selected subjects (group 3, n=100, average Western diet). Wear was visually recorded on oral, vestibular and occlusal/incisal surfaces using quantitative and morphological criteria. The mean age was 42.3±15.3 yr in group 1, 40.9±11.2 yr in group 2 and 36.7±11.7 yr in group 3. Group 1 exhibited the most pronounced substance loss, followed by groups 2 and 3. On occlusal surfaces, cupping was common in group 1 followed by group 2, but was rare in group 3. An inverse relation was found for facets. On buccal surfaces, no substance loss was observed in group 1, whereas in group 2, 63% had at least one tooth with a buccal lesion compared to 8% in group 3. The occlusal substance loss observed in subjects exposed to acids may be interpreted as increased abrasion/demastication of acid‐softened dental hard tissues. The occurrence of concavities on smooth surfaces appears to be significant for the diagnosis of dental erosion.
Task‐related electromyographic spectral changes in the human masseter and temporalis muscles
Authors: Farella Mauro , Van Eijden Theo , Baccini Michela , Michelotti Ambra
Published: December 2004

The masticatory muscles differ in their fiber type composition. It can therefore be expected that their electromyographic (EMG) power spectra will differ during the performance of different bite force tasks. In the present study, surface EMG activity was picked up from the masseter and from the anterior and posterior temporalis muscles of nine adult subjects. At a bite force level as low as 25 N, the mean power frequency (MPF) values of the posterior temporalis were significantly lower than those of the masseter and anterior temporalis. The MPF values of the masseter muscles decreased with an increase of bite force magnitude, whereas the MPF values of the anterior and posterior temporalis did not change significantly. The MPF values were significantly influenced by the direction of bite force. The observed changes of MPF are possibly related to the recruitment of different fiber types, and support the concept that the masticatory muscles behave heterogeneously.
The oral anti‐volatile sulphur compound effects of zinc salts and their stability constants
Authors: Young Alix , Jonski Grazyna , Rölla Gunnar
Published: December 2004

Volatile sulphur compounds (VSC) produced in the oral cavity, are a major cause of oral malodour. Zinc (Zn) ions inhibit VSC formation. The objective of this study was to examine whether Zn salts with low stability constants were more suitable as sources of Zn in lozenges than salts with high stability constants. The former provide free Zn ions upon dissolution in water, whereas the latter provide almost no free Zn. Identical lozenges containing Zn‐acetate and ‐gluconate, which have low stability constants, and Zn citrate and amino acid‐chelated Zn, which have extremely high stability constants, were tested. All the lozenges contained 0.9% w/w Zn. Ten volunteers sucked the lozenges until dissolved, and oral VSC were measured by gas chromatography. Zn‐acetate, ‐gluconate and ‐chelate had an impressive anti‐VSC effect even 3 h after the lozenges were taken. Zn citrate had significantly less effect than the other lozenges except Zn acetate after 2 and 3 h. It was concluded that the anti‐VSC effect was not related to the stability constants of the Zn compounds tested. Alternative ligands, with stronger affinity for Zn than the ligands in the lozenges, must be present in the oral cavity to explain these results. It is suggested that the sulphide ion may serve this function.
Effects of resin based dental composites on fertility of male mice
Authors: Al‐Hiyasat Ahmad S. , Darmani Homa , Elbetieha Ahmed M.
Published: December 2004

The purpose of this study was to investigate the effect of leached substances from dental composites on the fertility of male mice. Twenty adult male Swiss mice were divided into two groups of 10. Leached substances from composite specimens were administered, intragastrically, daily to the mice in the test group and distilled water to the control group for 28 d. Each mouse from both groups was mated with two untreated females. After mating, fertility of male mice in both groups was assessed. There was a significant reduction in the number of pregnancies in females mated with test males in comparison to those mated with control males (12/20 vs. 18/20, respectively). Females impregnated by test male mice showed a significant increase in the number of resorptions out of the total number of implantations (11% test vs. 1.5% control). The testicular sperm count and daily sperm production of the males in the test group was significantly reduced. Moreover, the relative weights of the testes and seminal vesicles were also significantly reduced in the test group. These results suggest that leached components from resin based dental composite materials have an adverse effect on the fertility and reproductive system of male mice.
Comparison of antiadhesive and antibacterial effects of antiseptics on Streptococcus sanguinis
Authors: Decker Eva‐Maria , Weiger Roland , Wiech Ilona , Heide Peter‐Edgar , Brecx Michel
Published: December 2004

Three antiseptic (chlorhexidine, Olaflur, Octenisept) and one putative antiadhesive (chitosan) agent were investigated for their effect on viable planktonic and attached Streptococcus sanguinis cells. The bacterial pretreatment with each chemotherapeutic was performed in two steps: (i) After the exposure of planktonic streptococci to the antiseptics, the cells were suspended in human sterile saliva and allowed to attach to human enamel for 60 min; (ii) After 60 min in the flow chamber system, initially attached streptococci were treated with these agents. The microbial viability was monitored by the percentage of vital streptococci determined by fluorescence microscopy and cell reproduction. In comparison with the negative control NaCl, the non‐bactericidal chitosan derivative showed distinctive antiadhesive properties. For both treatment procedures, the efficacy of the antiseptics in reducing the viability of planktonic and attached streptococci was Octenisept > Olaflur > chlorhexidine > saline > chitosan. Further studies appear warranted to develop new antiplaque/antibiofilm strategies involving highly efficient bactericidals with antiadhesive formulations.
Consideration of steroids for endodontic pain
Authors: Marshall J. Gordon
Published: December 2004

Up to 80% of endodontic patients who report with preoperative pain continue to experience some level of pain following the endodontic procedure. Since endodontic pain is often associated with chronic inflammation, the presence of bacterial by‐products, influx of primed immune cells and activation of the cytokine network and other inflammatory mediators, pain may be reduced by administration of glucocorticoid steroids. This review will include the pharmacology, pharmacodynamics and purported mechanisms of actions of steroids as well as their indications for endodontics, contraindications, dosages and side‐effects.
Brisk Walking Speed in Older Adults Who Walk for Exercise
Authors: Parise Carol , Sternfeld Barbara , Samuels Steven , Tager Ira B.
Published: December 2004

Objectives: To determine the self‐selected exercise intensity of older adults who report that they walk briskly for exercise. An additional aim of the study was to assess the contribution of self‐reported physical activity to self‐selected exercise intensity.

Design: Observational.

Setting: Community walking path.

Participants: Subjects consisted of 212 participants in the Study of Physical Performance and Age‐Related Changes in Sonomans who stated in a detailed home interview that they walked briskly for exercise.

Measurements: Observed brisk walking speed was measured as the time it took participants to walk half a mile at “normal brisk walking speed.” Self‐reported physical activity was categorized as metabolic equivalent of the task (MET) in minutes of exercise reported in the previous 7 days. Physiological measures and body composition were obtained through laboratory evaluation.

Results: Men walked at an average speed±standard deviation of 5.72±0.69 km/h and women walked at an average speed of 5.54±0.64 km/ h. Self‐reported physical activity was not associated with brisk walking speed when adjusted for age and ratio of lean to fat mass.

Conclusion: This study found that older adults who report that they walk briskly for exercise do so at a pace considered moderate or greater in absolute intensity as indicated by their walking speed (4.83 km/h). Ninety‐eight percent of men (93/95) and 97% of women (113/117) hadanobservedwalking speed equivalent to 3 or more METs based on their calculated walking speed.
Predator hunting behaviour and prey vulnerability
Authors: Quinn J. L. , Cresswell Will
Published: December 2004

Game theoretic models of how animals manage predation risk have begun to describe predator responses to prey behaviour relatively recently. This is partly because our understanding of how terrestrial predators select vertebrate prey is often limited to numerical and functional responses to measures of prey abundance. Prey vulnerability, however, may improve our understanding of predation because predators could maximize foraging success by selecting prey on this basis.

We tested the hypothesis that sparrowhawks (Accipiter nisusL.), a typical generalist predator, hunt redshanks (Tringa totanusL.), a favoured prey species on coastal shores, primarily on the basis of their vulnerability rather than their abundance.

Five direct measures or indicators of redshank behaviour predicted sparrowhawk attack success in a multipredictor statistical model and therefore serve as measures of redshank vulnerability.

These and other vulnerability measures influenced whether sparrowhawks decided to hunt redshanks on saltmarsh habitat. A model that included most of these measures predicted correctly whether sparrowhawks hunted redshanks (attack decision) 90% of the time and accounted for up to 75% of variation. Prey abundance accounted for no additional variation.

Thus the hunting behaviour of some predators can only be predicted well by several highly dynamic and interacting factors related to prey vulnerability. These results mean that, theoretically at least, the management of prey populations may sometimes be achieved best by manipulating prey vulnerability, rather than by culling their predators.
Colony specific morphological caste differences in an Old World, swarm‐founding polistine,Ropalidia romandi(Hymenoptera: Vespidae)
Authors: Fukuda Hirokazu , Kojima Jun‐ichi , Jeanne Robert L.
Published: December 2004

Morphological differences between queens and workers in an Australian swarm‐founding paper wasp,Ropalidia romandi, were examined, providing detailed information on the nature of morphological caste differences in swarm‐foundingRopalidiafor the first time. Queens and workers differed in overall size and had divergent shapes, but differences were not always significant. In colonies in which queen–worker dimorphism was distinct, while the head width of queens was nearly the same as that of workers, queens were significantly larger in measures on the metasoma than workers. Plotting of metasomal variables against the mesosomal length and analysis of covariance showed that queen–worker morphological differentiation inR. romandicannot be explained by simple linear allometric growth, suggesting that the two castes diverge in their growth parameters in the preadult stage. The pattern of morphological caste difference varied among colonies or was colony specific; there was no clear correlation between caste differences and colony cycle progression. These results suggest that morphological caste differences inR. romandiare determined genetically or by interactions between genetic background and intrinsic factors and/or external conditions.
Estimation of the thermal separation of soil particles from the thermal conductivity under reduced air pressure
Authors: Momose T. , Kasubuchi T.
Published: December 2004

Knowledge of thermal conductivity of granular materials under reduced air pressure can be utilized for studying intricate mechanisms of heat transfer in two‐phase systems. We measured the thermal conductivity of three soils of varied texture and two sets of glass beads (GB) under reduced air pressure using a twin heat probe. We also predicted the thermal conductivity of a two‐phase system at reduced air pressure from the modified Woodside & Messmer equation based on the kinetic theory of gases. This equation includes a thermal separation of solid particles (d) defined by the heat conduction. We compared this separation with the geometrical mean separation of solid particles (D). The results showed a linear relation between d and D for the GB, and in all cases d was smaller than D. This suggests that conductive heat transfer in two‐phase GB takes place mainly through air spaces the dimension of which is smaller than D.

The d of a Red Yellow soil and an Ando soil, however, were about 200–300 times larger than D. This result seems to be related to the soil aggregation. We showed that in soil aggregates the conduction of heat through the solid was the dominant mode of heat transfer, and the micropores in a soil aggregate had very little effect on the diminished thermal conductivity under reduced air pressure. The decrease in the thermal conductivity of two‐phase soil under reduced air pressure is probably caused by the air molecules confined in interaggregate pore spaces rather than those in the intra‐aggregate pore spaces. The d of soils can be used to represent the thermal separation of the interaggregate pore spaces, and soil aggregates can be treated as single‐grained particles in evaluating heat conduction.
Frequencies of TAP1 and TAP2 gene polymorphisms in the Anatolian population
Authors: Özbaş‐Gerçeker F. , Özgüç M.
Published: December 2004

Anatolia has a long and complex record of immigration from various regions. Here, we have used TAP1 and TAP2 gene polymorphisms as genetic markers to study the relationship between the Anatolian population and other populations. A neighbour‐joining tree was constructed indicating the relatedness of European populations and the Anatolian population with respect to TAP1 and TAP2 allele frequencies.
Immunogenetics of the rare HLA‐B allele B*4408†
Authors: Street J. , Downing J. , Darke C.
Published: December 2004

The nucleotide sequence of exons 2 and 3 of B*4408 has been confirmed. This allele has now been found in five, apparently unrelated, north‐western European Caucasoid subjects, residing in Wales, on HLA haplotypes bearing: A*0201, Cw*0501 with DRB1*0401, DQA1*03, DQB1*0301 in four instances and DRB1*0701, DQA1*0201, DQB1*0202 in one instance. The unique serological reactivity of ‘HLA‐B44BO’ was established using up to nine B*4408 subjects and was easily identified using a variety of B44 and B62 antisera. The phenotype and gene frequencies of B*4408, in a sample of 40 473 subjects residing in Wales, were 0.01235% and 0.00006, respectively.
Serological identification of a non‐HLA antigen in Oriental populations
Authors: Yang K. L. , Schroeder M. L. , Cherng J. M. , Lin P. Y.
Published: December 2004

In a routine HLA antibody screening cross‐match test using the complement‐mediated lymphocytotoxicity (LCT) assay, we discovered an antibody, in a transfused Caucasian woman, recognizing an Oriental restricted antigen that does not appear to be associated with the human leukocyte antigen (HLA) system. The distribution of this ‘novel’ antigen in Oriental populations and its frequency in the Taiwanese Chinese population are reported.
Ionic concentrations in a blanket peat bog in northern England and correlations with deposition and climate variables
Authors: Adamson J. K. , Scott W. A. , Rowland A. P. , Beard G. R.
Published: December 2004

Soil solution was collected to identify seasonal trends in its chemistry and to examine relationships between the concentrations of ions and variables that may control them. Samples were collected fortnightly at 10 cm and 50 cm depth in a blanket peat soil at Moor House–Upper Teesdale National Nature Reserve in the northern Pennine uplands of England. Dissolved organic carbon at 10 cm peaked each summer and correlated most strongly with temperature. At both depths Na+ and Cl– were the dominant ions, reflecting the oceanic climate. Over the 3‐year sampling period, concentrations of the principal anions and cations at 10 cm varied little except during the autumns of 1994 and 1995 following unusually dry summers. At these times concentrations of SO42–‐S increased from < 3 μmol to a maximum of 430 μmol and were balanced by smaller increases in Na+, Mg2+, Ca2+ and H+. The SO42– concentration at 10 cm was most strongly correlated with depth to the water Table 3 weeks prior to sampling. At 50 cm depth in the peat a small increase in SO42– occurred only during the autumn of 1995, and the concentration of SO42– at this depth correlated most strongly with that at 10 cm. At neither depth were there any strong correlations with deposition. The increase in H+ concentration associated with the peak in SO42– at 10 cm depth represents a fall in pH from usual values around 4.2 to 3.5.

Deposition flux of ions in bulk precipitation at Moor House from weekly samplings 1994 to 1996 in kg ha−1 year−1. The UK flux is derived from 32 sites of the United Kingdom Precipitation Composition Monitoring Network 1992 to 1994 and the standard deviation (SD) relates to the variation between these sites (Review Group on Acid Rain, 1997)

Moor House flux
UK flux
UK SD

H+
0.31
0.26
0.10

Ca2+
4.07
3.58
1.86

Mg2+
3.37
3.62
2.62

K+
1.54

Fe2+
0.73

Al3+
0.44

Na+
29.32
25.77
19.27

Cl–
51.14
45.96
32.39

NO3–‐N
4.01
3.20
1.05

NH4+‐N
4.85
3.63
1.74

SO42–‐S
8.98
7.98
3.09

PO43–‐P
0.01
A 13C tracer study to identify the origin of dissolved organic carbon in forested mineral soils
Authors: Hagedorn F. , Saurer M. , Blaser P.
Published: December 2004

The relative contributions of sources of carbon in soils, such as throughfall, litter, roots, microbial decay products and stable organic fractions, to dissolved organic C are controversial. To identify the origin of dissolved organic C, we made use of a 4‐year experiment where spruce and beech, growing on an acidic loam and on a calcareous sand, were exposed to increased CO2 that was depleted in 13C. We traced the new C inputs from trees into dissolved organic C, into water‐extractable organic C, and into several particle‐size fractions. In addition, we incubated the labelled soils for 1 year and measured the production of dissolved organic C and CO2 from new and old soil C. In the soil solutions of the topsoil, the dissolved organic C contained only 5–10% new C from the trees. The δ13C values of dissolved organic C resembled those of C pools smaller than 50 µm, which strongly suggests that the major source of dissolved organic C was humified old C. Apparently, throughfall, fresh litter and roots made only minor contributions to dissolved organic C. Water‐extractable organic C contained significantly larger fractions of new C than did the natural dissolved organic C (25–30%). The δ13C values of the water‐extractable organic C were closely correlated with those of sand fractions, which consisted of little decomposed organic carbon. The different origin of dissolved and water‐extractable organic C was also reflected in a significantly larger molar UV absorptivity and a smaller natural 13C abundance of dissolved organic C. This implies that the sampling method strongly influences the characteristics and sources of dissolved organic C. Incubation of soils showed that new soil C was preferentially respired as CO2 and only a small fraction of new C was leached as dissolved organic C. Our results suggest that dissolved organic C is produced during incomplete decomposition of recalcitrant native C in the soils, whereas easily degradable new components are rapidly consumed by microbes and thus make only a minor contribution to the dissolved C fraction.
Sorption of primisulfuron on soil, and inorganic and organic soil colloids
Authors: Pusino A. , Petretto S. , Gessa C.
Published: December 2004

Inorganic and organic soil colloids are responsible for the sorption of many pesticides. We studied the sorption of the herbicide primisulfuron [methyl 2 N‐[[[[[4,6‐bis(difluoromethoxy)‐2‐pyrimidinyl]amino]carbonyl]amino]sulfonyl]benzoate] on Fe3+‐, Al3+‐, Ca2+‐ and Na+‐exchanged montmorillonite, soil organic matter (H+‐ and Ca2+‐saturated), amorphous iron oxide, and three soils in aqueous media. The sorption on soils was negatively correlated with pH. Ca2+‐ and Na+‐exchanged montmorillonites are ineffective in the sorption of primisulfuron. The sorption on Fe3+‐ and Al3+‐exchanged montmorillonite is rapid and follows the Freundlich equation. Fourier transform infrared (FT‐IR) and X‐ray powder diffraction studies of the Fe3+‐ and Al3+‐montmorillonite samples after the interaction with primisulfuron in chloroform solution suggest that primisulfuron is adsorbed and degraded in the interlayer. Humic acid is more effective in the sorption than is Ca humate, suggesting that the pH of the suspension (3.5 for humic acid and 6.0 for Ca humate) has a strong influence on the sorption of primisulfuron. Experiments on amorphous iron oxide indicate similar pH dependence. Infrared spectra indicate that the protonation of the pyrimidine nitrogen moiety of herbicide and subsequent hydrogen bonding with the surface hydroxyls of Fe oxide is the mechanism acting in the primisulfuron sorption.
Collaboration in scientific research: a critical need for freshwater ecology
Authors: Cullen Peter W. , Norris Richard H. , Resh Vincent H. , Reynoldson Trefor B. , Rosenberg David M. , Barbour Michael T.
Published: December 2004

1. Collaboration means actively working together to achieve things which could not be done alone. This article attempts to provide an overall, unified, guiding framework for collaboration in freshwater ecology by discussing aspects of collaboration at individual and organizational levels, and addressing international linkages.

2. The essential elements of collaboration are communication and trust, and effective project management. Barriers to effective collaboration include competition, organizational cultures and organizational instabilities.

3. The success of collaboration can be measured by tangible benefits such as increased numbers of peer‐reviewed publications, the production of working models and a number of intangible benefits.

4. Interactions between individuals lie at the heart of an effective collaboration; organizational arrangements should facilitate this interaction. Some governments are encouraging collaboration to increase cost efficiency and allocate accountability. This trend should continue on an international level.

5. Collaboration is a key to future research in freshwater ecology.
The responses to shade of seedlings of very small‐seeded tree and shrub species from tropical rain forest in Singapore
Authors: METCALFE D. J. , GRUBB P. J.
Published: December 2004

1. Newly germinated seedlings of six tree and shrub species with very small seeds (31–460 μg dry mass), one light‐demanding and five shade‐tolerant at the stage of establishment in the wild, were grown for 5 months in neutral shade houses with 0·5, 1, 3·5 and 7·5% daylight.

2. The ratio of yield in 7·5% to that in 1% was 8:1 for the light‐demanding Melastoma malabathricum but only 2:1 for the confamilial shade‐tolerator Pternandra echinata. The Pternandra, Urophyllum hirsutum, Ficus chartacea, Ficus grossularioides and Pellacalyx saccardianus showed a graded series of responses to irradiance, generally consistent with their apparent demands for light in the wild. In contrast, survival of very deep shade was not clearly related to light demand in nature.

3. The results support the conclusion drawn from observational studies that large seed size is not primarily adaptive in resisting shade but in resisting the associated risks of burial by litter, desiccation during dry spells, uprooting by birds and other kinds of damage by animals or falling debris.