bluuebunny/crossref_metadata_2025 huggingface dataset:
Scaled AMO calculations on the hydrogen molecule II. The 1s σ 2p σ 1∑ state
Authors: Brändas Erkki
Published: December 2004

A scaled version of the AMO method is applied to the 1sσ2pσ 1∑ state of the hydrogen molecule. A method to extend the domain of the mixing parameter λ to the whole complex plane is described and applied in the present calculation. All the parameters introduced have been varied completely. A considerable improvement in the computed energy values is found for large internuclear separations R. The comparison between our potential energy curve and the accurate curve calcualted by Kolos and Wolniewicz is studied and, for example, for R = 12 a.u. the energy difference is only 18% of that for R = 2.43 a.u. The equilibrium separation is found to be 2.140 a.u. in poor agreement with 2.429 a.u. obtained by the previously mentioned authors.

In the separated atom limit, the state under consideration does not dissociate into H+ + H−, although the ionic character of the wave function is dominating in the region 3 ≦ R ≦ 8 a.u. The connections with earlier calculations and methods, especially the scaled version of the MO–LCAO approximation, are also pointed out and discussed.
Improved lower bounds for the convergence radius of RS‐perturbation theory
Authors: Bingel W. A.
Published: December 2004

F. Rellich and T. Kato have given lower bounds for the convergence radius of Rayleigh–Schrödinger perturbation theory, if the perturbation operator is bounded relative to the unperturbed Hamiltonian. It is shown here that these lower bounds can usually be improved.
Molecular‐orbital calculations on some mesoionic compounds
Authors: Sundaram K. , Purcell William P.
Published: December 2004

Molecular‐orbital calculations have been performed on sydnone, sydnone imine, ψ‐oxatriazole, and isosydnone rings and their positive ionized forms by the Pariser–Parr–Pople–Brown–Heffernan method. The importance of elaborate open‐shell calculations and the effect of introducing nonneighbor core resonance integrals in this order of approximation are investigated. The available experimental data on closely related compounds are qualitatively in agreement with the calculated values. The computed charges and bond orders demonstrate that certain structural features are common to all five‐membered mesoionic ring systems and in agreement with recent experimental findings.
Scaled AMO calculations on the hydrogen molecule IV. General remarks
Authors: Brändas Erkki
Published: December 2004

The scaled version of the AMO method as applied to the hydrogen molecule is discussed. Additional information about previous calculations on H2 with similar approximations together with computations on excited states (states corresponding to the next lowest root of the secular equation) are reported. The asymptotic behaviour is particularly investigated.
Bounds for eigenfunctions of one‐electron molecular systems
Authors: Bazley Norman W. , Fox David W.
Published: December 2004

This article gives pointwise bounds for the wave functions of one‐electron molecular systems.
Théorie quantique du pouvoir rotatoire magnétique des molécules diamagnétiques. II. Applications
Authors: Smet P.
Published: December 2004

The general formalism of the variational theory of the Faraday effect established in the first part of this paper is now applied to the actual computation of the Verdet constant of the hydrogen molecule, of water and of some saturated hydrocarbons. The numerical results have a correct order of magnitude and even, for hydrogen, are rather close to the experimental value.
Convergent iterative solutions for the lowest state of a system with large perturbations
Authors: Weltin E.
Published: December 2004

Iterative methods for the calculation of the lowest eigenvalue and the corresponding eigenvector are derived from the partitioned Schrödinger equation in matrix form. While they have a formal similarity to the Brillouin‐Wigner perturbation expansion, they converge for a much wider class of matrices. The double iteration methods (DIM and DIMA) lead to a series of upper and lower bounds to the desired lowest eigenvalue in accordance with Löwdin's bracketing theorem and can be used in a strategy which insures convergence to the solution for arbitrarily large perturbations. A much more efficient single iteration method (SIMA) produces the proper solution even for numerically very ill‐conditioned matrices (large offdiagonal elements and small separation of the diagonal elements from the lowest). An important feature of the iterative methods is their insensitivity toward roundoff errors which makes them especially suited for very large matrices, where direct diagonalisation, for example by the Jacobi method, is impracticable.
Off‐Diagonal hypervirial relations
Authors: Bradley C. J. , Hughes D. E.
Published: December 2004

A generalization of a theorem on off‐diagonal hypervirial relations is obtained and is used to demonstrate when to expect exact solutions of eigenvalue problems using the hypervirial method. Links are established between the hypervirial method and other approximation methods. The harmonic oscillator and hydrogen atom problems are given as examples.
The variation method and the algebraic eigenvalue problem
Authors: Wallis A. , McElwain D. L. S. , Pritchard H. O.
Published: December 2004

The generalized algebraic eigenvalue problem (A − λB)x = 0 arises in the use of the variation method in quantum mechanics. If, within the limitations of the computer word‐length, the basis set used to expand the trial wave function is linearly dependent, the matrix B becomes singular. Three different algorithms designed to deal with this difficulty have been investigated, paying special attention to the problem of identifying which members of the basis set are effectively linearly dependent. The advantages and limitations of each method are discussed.
Correlation problems in atomic and molecular systems III. Rederivation of the coupled‐pair many‐electron theory using the traditional quantum chemical methodst
Authors: Čižek J. , Paldus J.
Published: December 2004

The equations of the coupled‐pair many‐electron theory (CPMET) for the closed shell systems are rederived both in the spin‐orbital and orbital forms without the use of second quantization, Wick's theorem or the technique of Feynman‐like diagrams. Only the Slater rules are used for the calculation of necessary matrix elements. A comparison with earlier papers shows clearly the usefulness and conceptual simplicity of the mathematical methods of quantum field theory both in the derivation of the CPMET, in spin‐orbital form, and in the process of excluding spin variables.
The isotropic invariants of fifth‐rank cartesian tensors
Authors: Boyle L. L. , Matthews P. S. C.
Published: December 2004

An orthonormal set of irreducible fifth‐rank tensors having the required permutation symmetry is constructed. Various problems not encountered in the analogous problem for tensors of ranks two, three, four and six are discussed.
A perturbed generalized eigenvalue equation for the helium atom. II
Authors: Woodward M. R. , Amos A. T. , Laughlin C.
Published: December 2004

The Schrödinger equation for helium is written as a generalized eigenvalue equation which is solved for the ground state using perturbation theory. Two zero order equations are used and defined implicitly by specifying their eigenvalues and eigenfunctions. In both cases the eigenfunctions are taken to be the complete discrete set of products of eigenfunctions of the generalized eigenvalue equation for the hydrogen atom. To complete the definition the zero order eigenvalues are needed and two different intuitive choices are made. In the better of our two calculations an energy of –2.9014 a.u. is obtained for helium using the perturbation theory to second order.
High orders corrections to the Van der, Waals–London forces. I. A model problem: Two interacting hydrogen molecules is the minimal basis set
Authors: Malrieu J. P.
Published: December 2004

The classical intermolecular Rayleigh‐Schrödinger perturbation expansion is used with a finite basis of simple products of single determinants. For two hydrogen molecules with a minimal basis set, one shows that the ring and ladder diagrams dominate the perturbation series. The contributions of the purely intermolecular convex and concave ring diagrams are summed at all orders. The mixed ladder‐ring diagrams are also included. The series converges if the norm of the first order perturbed wave function is smaller than ½. The summation multiplies the Van der Waals–London forces by an explicit factor.
Unrestricted Hartree‐Fock calculations of spin densities with orthogonalized atomic orbitals: Proton and 13C hyperfine splittings in some pi hydrocarbon radicals
Authors: Nanda D. N. , Narasimhan P. T.
Published: December 2004

The spin density distribution in a few hydrocarbon radicals has been calculated using orthogonalized atomic orbitals in the Unrestricted Hartree‐Fock formalism of Amos and Snyder and including certain more important two‐electron hybrid and exchange integrals and all the core‐resonance integrals. Our calculated spin densities for the cation and anion radicals of alternant hydrocarbons, which are now different due to the breakdown of the pairing theorem, are, in general, of the right relative order so that even the simple McConnell type of relation can account partly for the observed differences in the proton splittings between cations and anions. The proton splittings for position 2 of naphthalene and anthracene radical ions are correctly predicted, thus clearing up the well‐known cation‐anion anomaly for this position. Comparative calculations have been made to show that the spin density results are worsened with the neglect of the integrals of the type mentioned before. An empirical analysis correlating the observed 13C splittings and the spin density results over a non‐orthogonal basis set shows that the available 13C splittings in alternant hydrocarbon radical ions can be explained with a set of sigma‐pi parameters which are consistent with the theory. It is shown that even though the spin densities in cations and anions may be different, these can lead to similar 13C splittings.
Molecular‐orbital calculations on transition metal complexes, charge‐transfer spectra and the sequence of metal and ligand orbitals
Authors: Van Der Lugt W. Th. A. M.
Published: December 2004

An outline is given of a semi‐empirical scheme for molecular‐orbital calculations on transition‐metal complexes according to a revised INDO procedure. To judge the reliability of the results of the calculations, the charge‐transfer transitions of a number of complexes have been calculated and compared with experimental data. Both for the excitation energies and for the oscillator strengths the agreement is very satisfactory. With respect to the sequence of occupied metal and ligand orbitals it was found that for closed‐shell d6 and d8 systems the molecular orbitals which are mainly composed of metal d orbitals have a lower energy than the orbitals built up from ligand p orbitals. Calculations by the extended Hückel method and other similar schemes give the d orbitals as the highest occupied ones as a result of a bad approximation of the diagonal elements of the Fock matrix. The consequences for the interpretation of photo‐electron spectra of transition‐metal complexes are discussed.
The electronic states of icosahedral molecules
Authors: Boyle L. L.
Published: December 2004

After a brief discussion of progress in the theory of icosahedral molecules, the terms arising from simple electronic configurations are deduced from tables of symmetrized powers of representations previously published by the author.
A floating one centre perturbation treatment for H‐like molecules
Authors: Ali M. K. , Meath W. J.
Published: December 2004

Closed form one centre partial wave perturbation results are obtained through second order in the energy for H‐like molecules with arbitrary nuclear charges. The expansion centre for the method is taken at an arbitrary point along the internuclear axis and the zeroth‐order wave function is a screened “1s” function centred at the expansion point. Various fixed one centre calculations of other workers for the lsσ states of H and HeH++ and for the 2pσ state of HeH++ are generated as limiting cases of this more general treatment. The floating one centre perturbation results for the 1sσ states of H2+ and HeH++ are used as models for discussing the usefulness of allowing the expansion centre in the one centre method to be a function of nuclear configuration.
Localized orbital calculations of the bonding in SO, SO2F2, ClO3F and SOCL2
Authors: Guest M. F. , Hillier I. H.
Published: December 2004

Localized valence molecular orbitals have been obtained for SO, SO2F2, ClO3F and SOCl2 by the method due to Boys and Foster. The bonding in these molecules, in which the second row atom is exhibiting an excess valency, is discussed in terms of the form of these localized orbitals. The bonding of the second row atom to an oxygen atom is described by three bent bond orbitals, whilst bonding to a halogen atom is described by a single bond orbital. The participation of 3d functions in the various bonding and nonbonding orbitals is analysed in this localized orbital framework.
An alternative formalism for the method of intermediate Hamiltonians
Authors: Sack R. A.
Published: December 2004

The methods of intermediate Hamiltonians and of inner projections for the determination of lower bounds of eigenvalues of a Hermitian operator H are analysed and reformulated as linear matrix problems. Submatrices T which are only defined implicitly through the product TTd̊ are best represented in triangular form. If the subspace complementary to the subspace determining the inner projection can be subdivided with different lower bounds for H, the bounds for the eigenvalues can be further improved. The new formalism is applied to obtain crude lower bounds for the ground state of the helium atom, using only 2 × 2 and 3 × 3 matrices.
The site of protonation in amino‐substituted pteridines
Authors: Kapoor K. L.
Published: December 2004

SCF‐LCAO‐MO‐CI calculations made on 2‐ and 4‐amino‐, and 2,4‐diaminopteridines indicate that the most favorable site where the protonation can take place is N‐1.
Determination of one‐centre core integrals from the average energies of atomic configurations
Authors: Karlsson Göran , Zerner Michael C.
Published: December 2004

One‐center core integrals for valence orbitals are determined from the experimental average energies of neutral atomic configurations from Li through Zn. These values are compared with those estimated from CNDO/1, “INDO/1”, CNDO/2, “INDO/2” and with theoretical values calculated from a pseudo‐potential method. The agreement is good between values obtained from neutral atoms and from the psuedo‐potential calculation except for the 3d orbitals of the transition elements where the theoretically calculated integrals over single ξ functions are not realistic. These two methods reproduce both term and average configuration energies for the first two rows of atoms; the semiempirical method reliably reproduces them for the third row. The CNDO/1 and INDO/1 methods underestimate atomic energies, while the CNDO/2 and INDO/2 procedures fail rather poorly.

The propriety of using core integrals estimated semiempirically in molecular orbital calculations is discussed.
A floating spherical gaussian orbital model of molecular structure. XII. Analysis of energy terms affecting the geometry of the water molecule
Authors: Afzal M. , Frost A. A.
Published: December 2004

The energy terms arising in the water calculation by the FSGO method are analyzed as a function of the bond angle in order to gain insight into the reasons for the particular equilibrium configuration. The analysis is made in terms of symmetrically orthogonalized orbitals so as to exclude three‐ and four‐orbital electron repulsion terms.
Spin‐free wave functions in many‐electron perturbation theory. I. Closed‐shell systems
Authors: Shibuya Tai‐Ichi , Sinanoğlu Oktay
Published: December 2004

The Schrödinger equation of an N‐electron closed‐shell system is reduced to that for the spatial wave function Ψ by the aid of the theory of the symmetric (permutation) group SN. The first‐order perturbation equation based on the Hartree–Fock‐SCF model as the zero‐order solution is then solved by decomposing it into a set of soluble 1/2(N/2)[(N/2) + 1] equations for the pair‐correlation (first‐order) spatial wave functions. These spatial functions give the spatial parts of the pair functions in the spin orbital basis formulation, reducing also the number of independent pairs needed in the first order.
Spin‐free wave functions in many‐electron perturbation theory. II. Systems with one nonclosed shell
Authors: Shibuya Tai‐Ichi , Sinanoğlu Oktay
Published: December 2004

The formulation developed in Paper I for a closed shell system is extended for a system with one nonclosed shell. Roothaan's restricted Hartree–Fock (RHF) open‐shell wave function is taken as the zero‐order solution. The first‐order Schrödinger equation is then solved for the spatial part of the wave function by reducing it to a set of one‐ and two‐electron equations, using the properties of the symmetric group SN.
Ab initio Hartree‐Fock calculations of electronic wave functions for the c3πu state of H2
Authors: Truhlar Donald G.
Published: December 2004

Theoretical electronic wave functions, potential curves, and expectation values of some one‐electron properties are given for the c3IIu state of the hydrogen molecule. The calculations are carried out by the matrix Hartree‐Fock method and use a 2‐center basis of Slater‐type orbitals. A total energy of −0.7292 a.u. is obtained in the best calculation. Our potential curve is reasonably consistent with that calculated by Browne, but we have examined the region of small internuclear distances (those at and below Re for the ground state) more extensively than any previous calculation. At R ≦ 1.6 a.u. our calculated potential curve is in excellent agreement with experiment.
Applications of Padé approximants of type II in partitioning technique
Authors: Røeggen I.
Published: December 2004

Padé approximants of type II have been applied to solve equations of the type F(z) = 0. The method is compared with the first‐order iteration procedure, the Aitken‐Samuelson formula, and the Newton‐Raphson tangential method. As a test example the partitioning technique in its most simple form is applied to the Hamiltonian of a rigid symmetric‐top molecule in a static electric field. The proposed algorithm is found to be superior to the first‐order procedure and the Aitken‐Samuleson formula, and at least as effective as the Newton‐Raphson method.
Matrix elements in configuration interaction calculations
Authors: Sasaki Fukashi
Published: December 2004

A method is proposed for the calculation of matrix elements among various states of atoms. A set of tensor operators is the only entity in the formalism, and all formulas involve merely the vacuum expectation values of these tensor operators and the recoupling transformation coefficients. Some numerical examples are given for the Coulomb interaction matrix elements.
Møller–Plesset theory for atomic ground state energies
Authors: Binkley J. S. , Pople J. A.
Published: December 2004

Mø–Plesset theory, in which electron correlation energy is calculated by perturbation techniques, is used in second order to calculate energies of the ground states of atoms up to neon. The unrestricted Hartree–Fock (UHF) Hamiltonian is used as the unperturbed system and the technique is then described as unrestricted Mø–Plesset to second order (UMP2). Use of large Gaussian basis sets suggests that the limiting UMP2 energies with a complete basis of s, p, and d functions account for 75–84% of the correlation energy. Preliminary estimates of the contributions of basis functions with higher angular quantum numbers indicate that full UMP2 limits give even more accurate total energies.
A correlation study of Li ground state by the MCHF procedure
Authors: Fischer Charlotte Froese
Published: December 2004

Results are reported for multiconfiguration Hartree–Fock studies of correlation in the lithium ground state, which maintain orthogonality of orbitals within a configuration.

It is shown that when the 1s‐ and 2s‐orbitals are fixed at their Hartree–Fock value, configurations for which Brillouin's theorem holds may be important, particularly for atomic properties other than energy. The Fermi contact term is considered as an example.
A finite‐difference solution of the Hartree–Fock equations for diatomic molecules
Authors: Fimple W. R. , White S. P.
Published: December 2004

A more general application of the self‐consistent field iteration is coupled with a finite‐difference Newton–Raphson algorithm to solve the set of coupled second‐order integro‐differential equations with split boundary conditions which constitutes the Hartree–Fock problem for diatomic molecules. The N orbitals are assumed to be of the form ψα = Lα(λ) Mα (μ)eimαϕ (2π)−1/2, (α = 1, …︁, N), where λ, μ, and ϕ are the usual confocal elliptical coordinates. Requiring the expectation value of the electronic Hamiltonian to be stationary with respect to independent variations of the functions Lα and Mα, subject to constraints of orthonormality, leads to a set of coupled one‐dimensional differential equations for the functions Lα and Mα. In the new method a corresponding set of finite‐difference equations including the split boundary conditions for each function, as well as the Lagrange multipliers and associated constraints on normalization and orthogonality, are incorporated into a large system of nonlinear algebraic equations which is solved by means of a coupled self‐consistent field‐generalized Newton–Raphson iteration. As examples, calculations of the (1)2 1Σ and (1) (2pσu) 3Σ states of H2 are presented. The calculated energy for the 1Σ state of H2 is 99.985% of the three‐dimensional Hartree–Fock limit. The discrepancy is due to the assumed factored form of the orbitals ψα, and a generalization of the finite‐difference method is suggested to improve the results.
Lattice dynamics with second neighbor interactions. II. Green's formula
Authors: McIntosh Harold V. , Hehenberger Michael , Reyes‐Sanchez Rodolfo
Published: December 2004

A satisfactory definition of spectral density for the normal modes of lattice dynamics problems requires the study of singular recurrence relations which is carried out in detail for one‐dimensional chains with pth neighbor interactions. The relationship of transfer matrices to the dynamical matrix is explored in order to obtain Green's formula. By using Green's formula, a mapping is defined between Vn, whose basis is formed from the normal modes of vibration of an n‐particle chain, and V2p, which is the space of boundary conditions for the recurrsion equations. Most of the properties of this mapping may be deduced from a symplectic bilinear form in V2p which is associated with the Hermitean inner product in Vn. This symplectic form defines a geometry which is invariant under the recursion relation, as well as canonical initial and boundary conditions, and a maximal isotropic subspace which may be used to determine square summability of the normal modes and the spectral density in the limit as the number of particles becomes infinite.
Valence‐Electron theory using the thomas–fermi–dirac model: Application to the K atom and the K− ion
Authors: Goodisman Jerry
Published: December 2004

It is proposed to calculate electronic structure of atoms and molecules by combining the Thomas‐Fermi‐Dirac (TFD) theory and a correct quantum mechanical treatment. The potential generated from the TFD treatment of the positively charged cores contains no adjustable parameters and requires no modification for proper asymptotic behavior. To take the exclusion principle into account, the valence electron wave‐function is constructed from the n + 1st, n + 2nd, etc. solutions to the one‐electron Schrödinger equation using the core potential, where n is the number of core electrons. For the potassium atom, the simple calculations give excellent agreement with experiment for ionization potential, transition frequencies and intensities, magnetic susceptibility, and electric polarizability. From a two‐electron configuration interaction wave‐function for K−, a value for the electron affinity of K is obtained which agrees with experimental values.
Many‐electron theory in the Waller–Hartree spin‐free method
Authors: Lim T. K.
Published: December 2004

A many‐electron theory is developed for the determination of pure spin state wave‐functions and energies to avoid the difficulties in doing integration. The Waller–Hartree pure spin state wave‐functions are very convenient for this purpose. The required explicit formulas for the values of the Waller–Hartree wave‐functions Y(S, M) and ℋ︁Y(S, M) at some physical points are produced, where local orthonormal orbitals are used to simplify the calculation of ℋ︁Y(S, M). A method for the construction of these orbitals is given, and a transformation formula is also given to show the interchangability between the local energy expression and the conventional expectation energy integral.
An investigation into the relationship between water beetle (Coleoptera) distribution and land cover in Scotland and northeast England
Authors: Eyre M. D. , Foster G. N. , Luff M. L. , Staley J. R.
Published: December 2004

Aims  To determine the relationship between satellite‐derived land cover data and distribution patterns of water beetle species pools.

Location  A total of 687 British national grid 10 km squares in Scotland and 588 1 km grid squares in 99 10 km grid squares in northeast England.

Methods  Multivariate classification and constrained ordination analyses were used with water beetle species and land cover data.

Results  The major variation in both the Scotland and northeast England 10 km species pools was from squares with upland acid water habitats to squares with lowland fens and ponds whilst for the 1 km northeast England data it was from squares dominated by fast‐flowing streams and rivers to those with fens and ponds. The secondary variations in the 10 and 1 km analyses were the primary ones juxtaposed. Constrained ordination of the Scottish 10 km data showed upland land cover types to be most influential in determining species pool distribution whilst lowland covers were more important with both the 10 and 1 km northeast England pools. The three analyses showed that coastal cover had a relatively high influence on species pool distribution but no species pool group was dominated by coastal species.

Main conclusions  There were strong relationships between water beetle species pool distributions and the satellite‐derived land cover types dominating upland and lowland areas. The major variation in the northeast England species pool data differed at the two scales analysed. Results indicated that there is considerable potential for the synthesis of water beetle distribution and land cover data for use in environmental and conservation monitoring at both the regional and national scales.
Classifying general and specialist children's nursing competencies
Authors: Gibson Faith , Fletcher Margaret , Casey Anne
Published: December 2004

Background.  Whilst there is evidence in the literature to support the continuation of a children's nursing qualification, the distinction between generalist and specialist nursing is insufficiently comprehensive to distinguish children's nursing from other branches of nursing.

Aim.  To develop a definition of children's nursing and specialist children's nursing in terms of competencies as the basis for differentiating them from other forms of nursing.

Design.  A multi‐method comparative design incorporating a case study approach was used. This included a nominal group technique, focus groups, Delphi survey and semi‐structured interviews. Two arms of data collection were undertaken concurrently (during 1998–2000) with children's nurses (n = 146) and specialist children's nurses (children's cancer nurses, n = 37) from a number of centres in the United Kingdom (UK).

Findings.  The holistic competencies developed from the data exposed characteristics of knowledge, skills, abilities, values and qualities displayed in the context of professional work for both groups of nurses. A classification of competencies was developed inductively from the data by two independent researchers through the labelling, defining and ordering of competencies. The resulting hierarchy of competencies and sub‐competencies illustrates relationships between children's nurses and specialist children's nurses and provides a detailed definition of children's nursing and specialist children's nursing.

Conclusion.  There is a significant common element in these two areas of nursing practice, and generalist preparation in children's nursing is the foundation of specialist children's nursing practice. Generalist knowledge and skills are expanded in specialist practice and there is also evidence of specialist practice that is beyond the scope of general nursing practice.
Torsion of undescended testis in a man with Down's syndrome
Authors: PAPATSORIS ATHANASIOS G , MPADRA FILITSA , KARAMOUZIS MICHALIS , LIKAKI‐KARATZA ELENI , KARATZAS THEODOROS
Published: December 2004

Undescended testis is one of the most common disorders in Down's syndrome. We present an extremely rare case of torsion of an inguinal undescended testis in a 35‐year‐old patient with Down's syndrome. Surgical exploration revealed a rotated gangrenous testis, radical orchiectomy was performed, and pathological examination confirmed the diagnosis of testicular torsion.
Intratesticular varicocele: Report of two cases
Authors: POURBAGHER MIR ALI , GUVEL SEZGIN , POURBAGHER AYSIN , KILINC FERHAT
Published: December 2004

Intratesticular varicocele is a rare entity and describes dilated intratesticular veins radiating from the mediastinum testis into the testicular parenchyma. Scrotal ultrasonography of two patients who presented to our urology clinic due to left scrotal pain revealed multiple tubular structures in the testes with diameters of more than 2 mm. Duplex spectral analysis showed a reversed flow response to Valsalva's maneuver. Apropos of two cases, intratesticular varicocele is reviewed.
Sufficient prophylactic efficacy with minor adverse effects by intravesical instillation of low‐dose bacillus Calmette‐Guérin for superficial bladder cancer recurrence
Authors: IRIE AKIRA , UCHIDA TOYOAKI , YAMASHITA HIDEYUKI , MATSUMOTO KAZUMASA , SATOH TAKEFUMI , KOH HIDESHIGE , SHIMURA SATORU , IWAMURA MASATSUGU , BABA SHIRO
Published: December 2004

Background: Intravesical instillation of bacillus Calmette‐Guérin (BCG) is the most efficient strategy for prophylaxis of superficial bladder cancer recurrence. Adverse effects of BCG are major obstacles, but the reduction of BCG dose could minimize these effects. The efficacy and adverse effects of half‐dose (40 mg) BCG, Tokyo 172 strain, were prospectively evaluated.

Methods: A total of 93 patients with superficial bladder cancer (pTa or pT1) were sequentially assigned to receive either 40 or 80 mg of BCG after transurethral resection. BCG was administered weekly for 6 weeks postoperatively. Eighty patients observed longer than 12 months after BCG therapy (41, 40 mg group; 39, 80 mg group) were analyzed.

Results: BCG therapy course was completed in 71 patients. Tumor recurrence was recognized in 11 of 40 patients in the 40 mg group and in 5 of 31 patients in the 80 mg group. There was no significant difference in tumor recurrence rate between the two groups (P = 0.547). BCG therapy was withdrawn in 1 patient in the 40 mg group and in 8 patients in the 80 mg‐group because of BCG‐related adverse effects. The morbidity of BCG‐related toxicity was significantly higher in the 80 mg group.

Conclusion: Half‐dose of BCG Tokyo 172 strain had a similar efficacy and its toxicity was signi­ficantly lower compared to the standard dose. Thus, half‐dose of this strain might be suitable, at least for initial BCG therapy, for the prophylaxis of bladder cancer recurrence. Further study would be necessary to clarify the efficacy of low‐dose instillation in high‐risk patients.
Centaur database: an information system for aphid surveys and pest control
Authors: Zintzaras E. , Tsitsipis J. A.
Published: December 2004

The development and the use of an information system (Centaur) including aphid trapping data from suction and yellow traps are described. Centaur is a client‐server database on an NT server and the interface is in Windows. The system allows users to enter and retrieve data of aphid captures and to produce summaries of data at various time levels (daily, weekly, yearly) for specific sites. The data can be illustrated graphically and they can be exported or printed. In addition, the system allows the incorporation of biological data and morphological images, and maps which estimate the spatial distribution of aphids. The information retrieval is fast and user‐friendly. The system can be of considerable value for research, community ecology, plant protection, public and private authorities, plant protection specialists, agronomists, agrochemical companies, farmers and the agricultural industry as it can be used for decision support. The data can be used to make forecasts for risk and/or to give advice for timely interventions. The system is currently operated in Greece and includes data from 1993 but it can be applied to other European countries and can be used for other insect pests.
The efficiency of several sampling methods for Frankliniella occidentalis (Thysan., Thripidae) in strawberry flowers
Authors: González‐Zamora J. E. , Garcia‐Marí F.
Published: December 2004

Methods for sampling western flower thrips Frankliniella occidentalis (Pergande) (Thysan., Thripidae) in strawberry flowers were evaluated in three commercial plots by monitoring the population densities of adult and immature thrips throughout the growing season. Three types of flowers were sampled: open, senescent and petal fall, and three procedures were compared: a visual examination of flowers, a turpentine‐funnel method and a shake method. Open flowers showed higher population densities of adults, whereas senescent or petal fall flowers had a higher number of eggs and more damage symptoms. Seasonal changes in population density were similar for the three sampling procedures, although the turpentine method recovered more insects, especially larvae, than the other two methods. The turpentine procedure was the most efficient as it extracted almost 100% of adults and, in plots with no chemical sprays, nearly 100% of second instars and 50% of first instars. Regular control of thrips with pesticides reduced the percentage of larvae recovered with this procedure. The visual method spotted 80% of adults and 33% of larvae. The shake method extracted nearly 80% of adults but only 18% of larvae. The visual method is recommended for routine field samplings, especially for sampling adults and in plots regularly sprayed with pesticides, as it constitutes a cost‐effective method when time and efficiency are considered.
Mothers’ health post‐partum and their patterns of seeking vaccination for their infants
Authors: Turner Cathy , Boyle Fran , O’Rourke Peter
Published: December 2004

A cohort of 159 mothers were recruited post‐partum and followed for seven months to examine the relationship between mothers’ health post‐partum and their patterns of seeking vaccination for their infants. Vaccination records for infants were obtained from a state‐wide database. Only 44% of the mothers had maintained all age‐appropriate vaccinations for their infant up to six months of age. Mothers who had two or more older children were four times more likely to have an infant who was not age‐appropriately vaccinated at six months. Women experiencing mental health problems including anxiety and depression, seven months following the birth, were between three to five times more likely to have started the vaccination schedule late or not at all. The findings have implications for midwives and for nurses practising in maternal and child health, paediatrics and public health environments. Strategies focusing on enhancing mothers’ psychosocial well‐being postnatally through improved service delivery should improve their patterns of seeking vaccination for their infants.
Metabolism of homoharringtonine, a cytotoxic component of the evergreen plant Cephalotaxus harringtonia
Authors: Ni Dan , Ho Dah H. , Vijjeswarapu Mary , Felix Edward , Robyn Rhea P. , Newman Robert A.
Published: December 2004

Homoharringtonine (HHT), first isolated from the Chinese evergreen Cephalotaxus harringtonia, has been demonstrated to have a broad antitumor activity in rodents and antileukemic effects in humans. We found that HHT was metabolized to an acid product [HHT‐acid; 2′‐hydroxy‐2′‐(α‐acetic acid)‐6′‐hydroxy‐6′‐methylheptanoyl cephalotaxine] when incubated with either human plasma or mouse plasma in vitro. The conversion was faster, however, in mouse plasma, and was both time‐ and temperature‐dependent. Boiled plasma prevented the conversion of HHT to HHT‐acid, suggesting that the conversion was enzymatically mediated. When mice were given an intravenous (i.v.) injection of HHT (4 mg/kg), the HHT‐acid metabolite was found in both plasma and urine. In mice, HHT‐acid was detected in the plasma within 5 min of the i.v. injection of HHT and declined rapidly thereafter. The initial half‐lives (t ½α) of HHT and HHT‐acid were 9 and 17 min, respectively. Twenty‐four hours after HHT dosing in mice, approximately 29% of the dose was excreted in the urine as HHT and 20% as HHT‐acid. High‐pressure liquid chromatography and mass spectrometry were used to confirm the identity and quantify HHT and its metabolite, HHT‐acid. The HHT concentration inhibiting 50% of the growth of human leukemic HL‐60 cells was 20 ng/ml, while for HHT‐acid it was 14,500 ng/ml, indicating that the acid form was more than 700 times less cytotoxic than HHT. The lethal dose of HHT affecting 50%(LD50) of mice was 6.7 mg/kg, but HHT‐acid produced no apparent toxic effects at doses up to 280 mg/kg.
Airways infection with virulent Mycobacterium tuberculosis delays the influx of dendritic cells and the expression of costimulatory molecules in mediastinal lymph nodes
Authors: García‐Romo Gina S. , Pedroza‐González Alexander , Aguilar‐León Diana , Orozco‐Estevez Hector , Lambrecht Bart N. , Estrada‐Garcia Iris , Flores‐Romo Leopoldo , Hernández‐Pando Rogelio
Published: December 2004

Despite tuberculosis resurgence and extensive dendritic cell (DC) research, there are no in vivo studies evaluating DC within regional lymphoid tissue during airways infection with virulent Mycobacterium tuberculosis (Mtb) H37Rv. Using DC‐specific antibodies, immunocytochemistry, flow cytometry and Ziehl–Neelsen (ZN) for bacilli staining, we searched for Mtb and DC changes within mediastinal lymph nodes, after intratracheal (ITT) inoculation of virulent Mtb. ZN and immunocytochemistry in frozen and paraffin sections of mediastinal lymph nodes identified Mtb until day 14 after ITT inoculation, associated with CD11c+ and Dec205+ DC. Analysing CD11c, MHC‐CII, and Dec205 combinations by flow cytometry in MLN suspensions revealed that CD11c+/MHC‐CII+ and CD11c+/Dec205+ DC did not increase until day 14, peaked on day 21, and sharply declined by day 28. No changes were seen in control, saline‐inoculated animals. The costimulatory molecules evaluated in CD11c+ DCs followed a similar trend; the CD80 increase was negligible, slightly surpassed by CD40. CD86 increased earlier and the three markers peaked at day 21, declining by day 28. While antigen‐specific proliferation was not evident for MLN CD4+ T cells at 2 weeks postinfection, delayed‐type hypersensitivity responses upon ITT inoculation revealed that, as early as day 3 and 7, both the priming and peripheral systemic immune responses were clearly established, persisting until days 14–21. While airways infection with virulent Mtb triggers an early, systemic peripheral response maintained for three weeks, this seems dissociated from regional events within mediastinal lymph nodes, such as antigen‐specific T‐cell reactivity and a delay in the influx and local activation of DC.
Internet‐based information systems use in organizations: an information studies perspective
Authors: Detlor Brian
Published: December 2004

Abstract. This case study investigates various ways in which different internet‐based information systems (IS) are used by organizational participants. Borrowing theoretical insights on information behaviour accumulated over 50 years of information studies research, a conceptual framework is presented to help understand and assess the social and organizational impacts of internet‐based IS. The framework describes the use of internet‐based IS as a dynamic cycle of information needs–seeking–use activity situated in the context of a firm's information environment. Research questions pertain to the process of how individuals in organizations seek and use information from internet‐based IS to satisfy information needs. In terms of information needs, this involves understanding the problem situations that lead participants to use internet‐based IS, as well as the characteristics of those problems beyond subject matter. With respect to information seeking, this involves analysing how information from internet‐based systems is displayed and formatted to signal their potential usefulness. In terms of information use, this involves how information obtained from internet‐based systems is used in practice to resolve or redefine problems. Both quantitative and qualitative research methods are used. Data collection involves web tracking to identify significant episodes of internet‐based IS activity, as well as one‐on‐one interviews to explore the context behind these episodes. Results suggest that it is possible and valuable to identify scenarios of internet‐based IS use dominant in an organizational work setting. Doing so can help to identify ways to improve the situated use of internet‐based IS that ameliorate the information needs–seeking–use cycle in firms.
Dynamics of Rickettsia–tick interactions: identification and characterization of differentially expressed mRNAs in uninfected and infected Dermacentor variabilis
Authors: Mulenga A. , Macaluso K. R. , Simser J. A. , Azad A. F.
Published: December 2004

To begin to explore the molecular dynamics of rickettsial tick interaction, subtractive hybridization was used to screen mRNAs in Rickettsia montanensis‐infected and uninfected Dermacentor variabilis. We isolated 30 cDNA fragments, 22 of which were up‐regulated and eight were down‐regulated in response to rickettsial infection. Based on a putative identity of 11 cDNA fragments with similarity to known protein families, the tick genetic factors have been assigned into three groups including, the tick immune response factors (α‐2 macroglobulin and IgE‐dependent histamine release factor), the receptor/adhesion molecules (the signal transducer and activator of transcription‐1/3 protein inhibitor, the clathrin adaptor protein and tetraspanin) and the stress response proteins (aldose reductase, glutathione‐S transferase, ferritin, nucleosome assembly protein and cyclin A protein). Density analyses of semiquantitative RT‐PCR amplified products demonstrated differential expression for 18 of the 23 tested genetic factors, apparently representing a 78% agreement with results obtained by subtractive hybridization. Additionally, mRNA transcripts of 17 of the 23 tested genetic factors were amplified from tick haemocytes/circulatory cells demonstrating that their expression is not restricted to the ovaries and suggesting a potential involvement in the immune response.
Amplifying whole insect genomes with multiple displacement amplification
Authors: Gorrochotegui‐Escalante N. , Black IV W. C.
Published: December 2004

Many applications in insect genetics require repeated analyses on individual organisms. These include population genetic and genomics, linkage mapping, molecular systematics and map‐based positional cloning. However, using the polymerase chain reaction, a limited number of analyses are possible with DNA isolated from whole bodies or parts of small or preserved specimens. We describe the optimization of a new technique, Multiple Displacement Amplification, for 100–400‐fold amplification of whole mosquito genomes. We demonstrate that MDA amplifies genomic DNA directly from an adult leg or from organisms as small as a first instar mosquito larva. Genetic polymorphisms revealed at individual loci are the same whether using the original genomic DNA or MDA DNA as a template.
Accidentally induced periodontitis in primary dentition: longitudinal examinations of periodontal bacteria and clinical conditions
Authors: Ooshima T. , Nishiyama N. , Tamura K.
Published: December 2004

Summary Periodontitis is very rare in the primary dentition although it can be accidentally induced in young children. The purpose of this study was to describe a case of periodontitis in a 4‐year‐old child, which was accidentally induced by insertion of small plastic tubes into the dental cervix of the primary incisors during play, and to discuss the clinical, radiographic, and microbiological findings. Removal of the plastic tubes resulted in resolution of the periodontal condition. Prevotella nigrescens and Campylobacter rectus were detected in subgingival plaque samples from the affected teeth at every examination, whereas Porphyromonas gingivalis, Treponema denticola, Prevotella intermedia, and Bacteroides forsythus were never found during the two‐year observation period. The clinical and microbiological results suggest that the type of periodontitis caused by such an incidence is not progressive, unlike other periodontal diseases such as prepubertal and juvenile periodontitis.
Compound odontoma associated with an unerupted and dilacerated maxillary primary central incisor in a young patient
Authors: Yeung K. H. , Cheung R. C. T. , Tsang M. M. H.
Published: December 2004

Summary.  The occurrence of odontoma in the primary dentition is uncommon. There are very few reports of non‐eruption of a dilacerated primary tooth in the literature. A rare case of compound odontoma in association with an unerupted dilacerated maxillary primary incisor in a young patient is reported. There was also a developing supernumerary tooth in the vicinity of the odontoma. The clinical features and management of these conditions are discussed. The relevant literature is reviewed. A possible causal relationship between odontoma and dilaceration is highlighted.