bluuebunny/crossref_metadata_2025 huggingface dataset:
Third Place—Resident Clinical Science Award 1998: Effects ofCis‐Platinum Chemotherapy on Otoacoustic Emissions: The Development of an Objective Screening Protocol
Authors: Ress Bradford D. , Sridhar Kasi S. , Balkany Thomas J. , Waxman Geoffrey M. , Stagner Barden B. , Lonsbury‐Martin Brenda L.
Published: April 2004

To develop an objective, fast, and simply performed screening protocol forcis‐platinum (CP) ototoxicity, we compared the efficacy of screening with distortion‐product otoacoustic emissions (DPOAEs) with the outcome of both conventional and ultra‐high‐frequency (UHF) audiometry. Baseline audiometric and DPOAE testing was performed in 66 patients, 33 of whom met criteria for inclusion in the final database. Comparisons were made between baseline measurements and those recorded before subsequent CP infusions. Outcomes were analyzed clinically and with paired repeated‐measures analysis of variance. Results indicated that DPOAEs and UHF were better measures than conventional audiometry. Further, DPOAEs may be better suited for screening older patients receiving CP chemotherapy because DPOAEs are as sensitive as UHF and are present in a greater number of these patients. Screening with DPOAEs may be enhanced by testing only in the 3‐ to 5.2‐kHz range, thus decreasing testing time. Higher time averages to increase the signal‐to‐noise ratio and use of this narrower bandwidth might also allow for accurate bedside testing.
Rise of oxygenation in cervical lymph node metastasis during the initial course of radiochemotherapy
Authors: Dietz Andreas , Rudat Volker , Vanselow Bernhard , Wollensack Petra , Bettscheider Claudia , Conradt Christian , Eble Michael J.
Published: April 2004

It has been hypothesized that during radiation treatment a reoxygenation of hypoxic tumor tissue takes place. To test this hypothesis, we have investigated whether reoxygenation in lymph node metastases could be determined by invasive Po2 measurements. Through a hypodermic needle inserted transcutaneously into tumor‐Positive lymph nodes, Polarographic oxygen determinations were made in 18 patients with advanced squamous cell carcinomas of the oropharynx and hypopharynx. These measurements were performed before therapy and a week after the onset of radiotherapy or radiochemotherapy, respectively. Low Po2 values before treatment (mean value of the patient's median was 12.6 mm Hg Po2) and a mean hypoxic fraction (Po2 < 5 mm Hg) of 39.6% indicated manifest tumor hypoxia. After 1 week of treatment, a significant increase in the median PO2 (mean value of shift: 7.3 mm Hg) and a reduction in the hypoxic fraction (mean value of shift: 13.4% Po2 < 5 mm Hg, P < 0.03) were observed after both radiotherapy and radiochemotherapy. Thus invasive PO2 histography fulfills the requirements for a method to confirm tumor hypoxia in head and neck tumors. The results obtained indicate that reoxygenation occurs during the initial phases of radiotherapy and radiochemotherapy, and they will form the basis for future comparative investigations on the Possible influence of hypoxic parameters on tumor responsiveness toward radiation and radiochemotherapy.
Proposed classification scheme for quantitative olfactory function alterations
Authors: Gil‐Carcedo Luis Maria , Gil‐Carcedo Elisa , Vallejo Luis Angel , Ortega Primitivo
Published: April 2004

Given the need for a clinical classification for daily patient examinations to refer to each type of quantitative alteration in the sense of smell, we have created a topographic classification of such alterations, establishing groups to distinguish among patients with decreased or total loss of olfaction. Because the classification is based on the diagnosis of the different causes of anosmia, it implicitly includes etiologic and topographic considerations. We have established 3 main groups on the basis of the site of the causal lesion: conduction, sensorineural, and mixed anosmias. In addition, within the sensorineural anosmias, we distinguish between the epithelial, retroepithelial, and central anosmias.
Relating speech and swallow function to dropout in a longitudinal study of head and neck cancer
Authors: Colangelo Laura A. , Logemann Jeri A. , Rademaker Alfred W. , Pauloski Barbara Roa , Smith Christina H. , McConnel Fred M. S. , Stein David W. , Beery Quinter C. , Myers Eugene N. , Heiser Mary Anne , Cardinale Salvatore , Shedd Donald P.
Published: April 2004

The relation between functional outcome and dropout from a 12‐month follow‐up period was examined in a longitudinal study whose objective was to define and quantify the functional effects of oral surgical resection and reconstruction on speech and swallowing in patients with head and neck cancer. In a group of 150 patients recruited to a surgical study in the Cancer Control Science Program in Head and Neck Cancer Rehabilitation, dropout from all causes and dropout from specific causes (medical, patient, and administrative specific) were assessed in relation to longitudinal speech and swallow function. In univariate analysis, better speech articulation was associated with decreased risk of dropout from all causes and from medical‐specific causes. Better swallow performance was associated with decreased risk of medical‐specific dropout. Multivariate analysis revealed the following: (1) only articulation function was associated with dropout from all causes; (2) the association of speech articulation function with medical dropout was diminished after adjusting for advanced age and surgical resection variables; (3) the association of speech articulation function became significant for patient‐specific dropout after adjusting for advanced age and surgical resection variables and indicated that better function decreased the risk of this type of dropout; and (4) swallowing function was not related to dropout. Patients treated for oral or oropharyngeal cancer who have Poorer speech outcomes are more likely to drop out from a longitudinal study. Basing study results on only patients who complete a longitudinal study will understate the level of dysfunction experienced.
Use of upper lip flap for Correction of nostril stenosis
Authors: Mavili Emin , Akyürek Mustafa
Published: April 2004

Stenosis of the nostril is a very rare deformity. It may be either congenital or acquired, arising as a result of loss of the vestibular lining. The causes of the acquired form include (1) infections, (2) trauma, and (3) iatrogenic, after excision or electrocoagulation of tumors, chemical cauterization, prolonged nasal packing under tension, and other procedures that damage the vestibular lining.1
Unique Characteristics of Malignant Schneiderian Papilloma
Authors: Nachtigal Dan , Yoskovitch Adi , Frenkiel Saul , Braverman Itzhak , Rochon Louise
Published: April 2004

PURPOSE

To ascertain the characteristics unique to malignant schneiderian papilloma (MSP).

METHODS

A case‐control study of all schneiderian papilloma (SP) patients treated between 1978 and 1997 was conducted. Comparison was made between patients with MSP and patients with benign SP (BSP).

RESULTS

A diagnosis of SP was made in 72 patients. Malignant changes, all of them the inverted papilloma subtype, were found in 8 of these patients. Three were diagnosed carcinoma in situ, and 5 were defined as invasive squamous cell carcinoma. At presentation, the MSP patients had significantly larger tumor spread into the ethmoid and sphenoid sinuses. The recurrence rate was significantly lower in SP patients treated with extensive surgical procedures. An association was found between the presence of malignant lesions and Positive smoking history, subjective awareness of a nasal mass, and ethmoid and sphenoid sinus involvement. Also, histologic multicentricity was a feature more often seen in MSP than BSP and was a significant correlate with malignancy.

CONCLUSION

The physician evaluating a patient with SP should be aware of the features described and of their Possible association with a malignant lesion.
Experimental studies of high-frequency azimuthal waves in Hall thrusters
Authors: Litvak Andrei A. , Raitses Yevgeny , Fisch Nathaniel J.
Published: April 2004

High-frequency oscillations (1–100 MHz) are drawing significant attention in the recent research of Hall thrusters. A diagnostic setup, consisting of single Langmuir probe, special shielded probe connector-positioner, and electronic impedance-matching circuit, was successfully built and calibrated. Through simultaneous high-frequency probing of the Hall-thruster plasma at multiple locations, high-frequency plasma waves have been successfully identified and characterized.
Modeling of a high-power thruster with anode layer
Authors: Keidar Michael , Boyd Iain D. , Beilis Isak I.
Published: April 2004

Among Hall thruster technologies, the thruster with anode layer (TAL) has much wider technical capabilities, especially in the high-power regime of operation. In this paper, various aspects of the plasma flow in a high-power thruster with anode layer are studied. Based on a 2D hydrodynamic model, the formation of a space-charge sheath near the acceleration channel wall and the sheath expansion in the acceleration channel are calculated. It is found that the high-voltage sheath near the channel wall expands significantly and the quasineutral plasma region is confined in the middle of the channel. For instance, in the case of a 3 kV discharge voltage, the sheath thickness is about 1 cm, which is a significant portion of the channel width (which is typically a few cm). In addition, a simplified quasi-1D model is developed to study the anode acceleration layer, which is confined by channel walls. It is found that near-wall sheath expansion leads to an increase in current density along the channel, and this in turn causes decrease of the acceleration region length. This is an important finding as it has implications for high-power TAL behavior, in which contact of the plasma with acceleration channel walls can be limited.
Instability of the Shukla mode in a dusty plasma containing equilibrium density and magnetic field inhomogeneities
Authors: Shukla P. K. , Bharuthram R. , Schlickeiser R.
Published: April 2004

It is shown that the dispersive Shukla mode [P.K. Shukla, Phys. Lett. A 316, 238 (2003)] can become unstable in the presence of equilibrium density and magnetic field inhomogeneities in a dusty plasma. A new dispersion relation for our nonuniform dusty magnetoplasma is derived and analyzed to show the modification of the Shukla mode frequency and its amplification due to combined action of the plasma density and magnetic field gradients. The present instability may account for the origin of low-frequency electromagnetic turbulence in molecular clouds and in cometary plasmas.
Kinetic simulation of steady states of ion temperature gradient driven turbulence with weak collisionality
Authors: Watanabe T.-H. , Sugama H.
Published: April 2004

Statistically steady states of the ion temperature gradient driven turbulence with weak collisionality, where the collision frequency is much lower than characteristic ones of the turbulence, are investigated by means of a Eulerian kinetic simulation with high resolution. In the saturated state of the entropy variable, the ion heat transport balances with the collisional dissipation that is indispensable to realizing a steady-turbulence state of perturbed distribution function δf. The kinetic simulation definitely confirms the conventional hypothesis that, in a low-collisionality limit, the low-order velocity-space moments of δf as well as the ion heat transport flux agree with those in the quasisteady state of the collisionless turbulence with the constant entropy production. A spectral analysis of δf in the velocity-space clarifies the transfer and dissipation processes of the entropy variable associated with fluctuations, where the phase mixing, the E×B nonlinearity, and the finite collisionality are taken into account. A power-law scaling predicted by the theoretical analysis is also verified by the simulations in a subrange of the power spectrum which is free from the entropy production and the collisional dissipation.
Ordered binary crystal phases of Lennard-Jones mixtures
Authors: Fernández Julián R. , Harrowell Peter
Published: April 2004

The lattice energies at zero temperature are calculated, using Lennard-Jones interactions, for a large number of crystal structures associated with ordered binary compounds. In units of the AA interaction length and strength (i.e., σAA=εAA=1.0) we examine the lowest energy structures, including coexisting phases, across the space of cross-species interactions 0.6⩽σAB⩽1.1 and 1.0⩽εAB⩽2.0. The remaining parameters σBB=0.88 and εBB=0.5 are chosen so that the parameter space studied includes the space of binary glass-forming alloys. In addition to some large unit cell structures such as Ni3P and PuBr3 appearing among the lowest lattice energies, a number of low-energy structures based on close-packed lattices are found that do not correspond to any experimentally observed crystals. The prevalence and stability of metastable crystal phases at the compositions AB, A2B, and A3B is examined.
Structures and stability of medium silicon clusters. II. Ab initio molecular orbital calculations of Si12–Si20
Authors: Zhu X. L. , Zeng X. C. , Lei Y. A. , Pan B.
Published: April 2004

Ab initio all-electron molecular-orbital calculations are carried out to study the structures and relative stability of low-energy silicon clusters (Sin,n=12–20). Selected geometric isomers include those predicted by Ho et al. [Nature (London) 392, 582 (1998)] based on an unbiased search with tight-binding/genetic algorithm, as well as those found by Rata et al. [Phys. Rev. Lett. 85, 546 (2000)] based on density-functional tight-binding/single-parent evolution algorithm. These geometric isomers are optimized at the Møller–Plesset (MP2) MP2/6-31G(d) level. The single-point energy at the coupled-cluster single and double substitutions (including triple excitations) [CCSD(T)] CCSD(T)/6-31G(d) level for several low-lying isomers are further computed. Harmonic vibrational frequency analysis at the MP2/6-31G(d) level of theory is also undertaken to assure that the optimized geometries are stable. For Si12–Si17 and Si19 the isomer with the lowest-energy at the CCSD(T)/6-31G(d) level is the same as that predicted by Ho et al., whereas for Si18 and Si20, the same as predicted by Rata et al. However, for Si14 and Si15, the vibrational frequency analysis indicates that the isomer with the lowest CCSD(T)/6-31G(d) single-point energy gives rise to imaginary frequencies. Small structural perturbation onto the Si14 and Si15 isomers can remove the imaginary frequencies and results in new isomers with slightly lower MP2/6-31G(d) energy; however the new isomers have a higher single-point energy at the CCSD(T)/6-31G(d) level. For most Sin (n=12–18,20) the low-lying isomers are prolate in shape, whereas for Si19 a spherical-like isomer is slightly lower in energy at the CCSD(T)/6-31G(d) level than low-lying prolate isomers.
Microwave and ab initio studies of rare gas–methane van der Waals complexes
Authors: Liu Yaqian , Jäger Wolfgang
Published: April 2004

Rotational spectra of the weakly bound Kr–methane van der Waals complex were recorded using a pulsed molecular beam Fourier transform microwave spectrometer in the range from 3.5 to 18 GHz. Spectra of 25 isotopomers of Kr–methane were assigned and analyzed. For isotopomers containing CH4, CH413, and CD4, two sets of transitions with K=0 and one with K=1 were recorded, correlating to the j=0, 1, and 2 rotational levels of free methane, respectively (j is the rotational angular momentum quantum number of the methane monomer). For isotopomers containing CH3D and CHD3, two K=0 components were recorded, correlating to the jk=00 and 11 rotational levels of free methane (k corresponds to the projection of j onto the C3 axis of CH3D and CHD3). The obtained spectroscopic results were used to derive van der Waals bond distance R, van der Waals stretching frequency νs, and the corresponding stretching force constant ks. Nuclear spin statistical weights of individual states were obtained from molecular symmetry group analyses and were compared with the observed relative transition intensities. The tentatively assigned j=2 transitions were more intense than predicted from symmetry considerations. This is attributed to a relatively large effective dipole moment of this state, supported by ab initio dipole moment calculations. Ab initio potential energy calculations of Kr–CH4 and Ar–CH4 were done at the coupled cluster level of theory, with single and double excitations and perturbative inclusion of triple excitations, using the aug-cc-pVTZ basis set supplemented with bond functions. The theoretical results show that the angular dynamics of the dimer does not change significantly when the binding partner of methane changes from Ar to Kr. The dipole moment of Ar–CH4 was calculated at various configurations, providing a qualitative explanation for the unsuccessful spectral searches for rotational transitions of Ar–CH4.
Microscopic theory of rubber elasticity
Authors: Oyerokun Folusho T. , Schweizer Kenneth S.
Published: April 2004

A microscopic integral equation theory of elasticity in polymer liquids and networks is developed which addresses the nonclassical problem of the consequences of interchain repulsive interactions and packing correlations on mechanical response. The theory predicts strain induced softening, and a nonclassical intermolecular contribution to the linear modulus. The latter is of the same magnitude as the classical single chain entropy contribution at low polymer concentrations, but becomes much more important in the melt state, and dominant as the isotropic–nematic liquid crystal phase transition is approached. Comparison of the calculated stress–strain curve and induced nematic order parameter with computer simulations show good agreement. A nearly quadratic dependence of the linear elastic modulus on segmental concentration is found, as well as a novel fractional power law dependence on degree of polymerization. Quantitative comparison of the theory with experiments on polydimethylsiloxane networks are presented and good agreement is found. However, a nonzero modulus in the long chain limit is not predicted since quenched chemical crosslinks and trapped entanglements are not explicitly taken into account. The theory is generalizable to treat the structure, thermodynamics and mechanical response of nematic elastomers.
Rotational dynamics of CO solvated in small He clusters: A quantum Monte Carlo study
Authors: Cazzato Paolo , Paolini Stefano , Moroni Saverio , Baroni Stefano
Published: April 2004

The rotational dynamics of CO single molecules solvated in small He clusters (CO@HeN) has been studied using reptation quantum Monte Carlo simulations for cluster sizes up to N=30. Our results are in good agreement with the rotovibrational features of the infrared spectrum recently determined for this system and provide a deep insight into the relation between the structure of the cluster and its dynamics. Simulations for large N also provide a prediction of the effective moment of inertia of CO in the He nanodroplet regime, which has not been measured so far.
A new expression for the direct quantum mechanical evaluation of the thermal rate constant
Authors: Medvedev Dmitry M. , Gray Stephen K.
Published: April 2004

Based on the formalism of Miller, Schwartz, and Tromp [J. Chem. Phys. 79, 4889(1983)], we derive a new expression for the thermal rate constant for a chemical reaction. The expression involves an unperturbed, i.e., reactant or product channel Boltzmann operator for the imaginary time propagation, making it possible to compute efficiently the rate constant for a range of temperatures. We illustrate numerical aspects with an extensive study of the one-dimensional Eckart barrier problem, as well as a study of the three-dimensional (J=0) D+H2 problem.
A density-functional theory study of the confined soft ellipsoid fluid
Authors: Cheung David L. , Schmid Friederike
Published: April 2004

A system of soft ellipsoid molecules confined between two planar walls is studied using classical density-functional theory. Both the isotropic and nematic phases are considered. The excess free energy is evaluated using two different Ansätze and the intermolecular interaction is incorporated using two different direct correlation functions (DCF’s). The first is a numerical DCF obtained from simulations of bulk soft ellipsoid fluids and the second is taken from the Parsons–Lee theory. In both the isotropic and nematic phases the numerical DCF gives density and order parameter profiles in reasonable agreement with simulation. The Parsons–Lee DCF also gives reasonable agreement in the isotropic phase but poor agreement in the nematic phase.
Carbon–carbon bond cleavage in the photoionization of ethanol and 1-propanol clusters
Authors: Tsai Shang-Ting , Jiang Jyh-Chiang , Lin Ming-Fu , Lee Yuan T. , Ni Chi-Kung
Published: April 2004

Tunable VUV laser was used to initiate the ion–molecule reactions in the clusters of ethanol and 1-propanol by photoionization in the region between 10.49 to 10.08 eV. Ionic products were detected by the time-of-flight mass spectrometer. In addition to the protonated clusters from proton transfer reactions, the products corresponding to β carbon–carbon bond cleavage were found to be one of the major products for small sizes of clusters. A comparison with photoionization of methanol clusters and the results of ab initio calculation has been made.
Charge ordering and interlayer phase coherence in quantum Hall superlattices
Authors: Shevchenko S. I. , Fil D. V. , Yakovleva A. A.
Published: April 2004

The possibility of the existence of states with a spontaneous interlayer phase coherence in multilayer electron systems in a high perpendicular magnetic field is investigated. It is shown that phase coherence can be established in such systems only within individual pairs of adjacent layers, while such coherence does not exist between layers of different pairs. The conditions for stability of a state with interlayer phase coherence against transition to a charge-ordered state are determined. It is shown that in a system with N⩽10 layers there is stability at any value of the interlayer distance d. For N>10 there are two intervals of stability: at sufficiently large and at sufficiently small d. For N→∞ the stability interval in the region of small d vanishes.
Quantum chemical calculation of infrared spectra of acidic groups in chabazite in the presence of water
Authors: Mihaleva V. V. , van Santen R. A. , Jansen A. P. J.
Published: April 2004

The changes in the spectra of the acidic group in chabazite are studied by quantum chemical calculations. The zeolite is modeled by two clusters consisting of eight tetrahedral atoms arranged in a ring and seven tetrahedral atoms coordinated around the zeolite OH group. The potential energy and dipole surfaces were constructed from the zeolite OH stretch, in-plane and out-of-plane bending coordinates, and the intermolecular stretch coordinate that corresponds to a movement of the water molecule as a whole. Both the anharmonicities of the potential energy and dipole were taken into account by calculation of the frequencies and intensities. The matrix elements of the vibrational Hamiltonian were calculated within the discrete variable representation basis set. We have assigned the experimentally observed frequencies at ∼2900, ∼2400, and ∼1700 cm−1 to the strongly perturbed zeolite OH vibrations caused by the hydrogen bonding with the water molecule. The ABC triplet is a Fermi resonance of the zeolite OH stretch mode with the overtone of the in-plane bending (the A band) and the overtone of the out-of-plane bending (the C band). In the B band the stretch is also coupled with the second overtone of the out-of-plane bending. The frequencies at ∼3700 and ∼3550 cm−1 we have assigned to the OH stretch frequencies of a slightly perturbed water molecule.
The unfolding kinetics of ubiquitin captured with single-molecule force-clamp techniques
Authors: Schlierf Michael , Li Hongbin , Fernandez Julio M.
Published: April 2004

We use single-molecule force spectroscopy to study the kinetics of unfolding of the small protein ubiquitin. Upon a step increase in the stretching force, a ubiquitin polyprotein extends in discrete steps of 20.3 ± 0.9 nm marking each unfolding event. An average of the time course of these unfolding events was well described by a single exponential, which is a necessary condition for a memoryless Markovian process. Similar ensemble averages done at different forces showed that the unfolding rate was exponentially dependent on the stretching force. Stretching a ubiquitin polyprotein with a force that increased at a constant rate (force-ramp) directly measured the distribution of unfolding forces. This distribution was accurately reproduced by the simple kinetics of an all-or-none unfolding process. Our force-clamp experiments directly demonstrate that an ensemble average of ubiquitin unfolding events is well described by a two-state Markovian process that obeys the Arrhenius equation. However, at the single-molecule level, deviant behavior that is not well represented in the ensemble average is readily observed. Our experiments make an important addition to protein spectroscopy by demonstrating an unambiguous method of analysis of the kinetics of protein unfolding by a stretching force.
Developmentally regulated IκB expression in intestinal epithelium and susceptibility to flagellin-induced inflammation
Authors: Claud Erika C. , Lu Lei , Anton Pauline M. , Savidge Tor , Walker W. Allan , Cherayil Bobby J.
Published: April 2004

Necrotizing enterocolitis is a devastating inflammatory condition of the intestine that occurs almost exclusively in premature newborns. Although its exact pathogenesis is unclear, we have postulated that it may result from a predisposition of the immature intestine to mount an unusually robust and damaging response to microbial infection. In support of this idea, we report that the IL-8 response of an immature human enterocyte cell line to bacterial infection was significantly higher than that of a mature enterocyte cell line. The response in both cell lines was flagellin-dependent. Corresponding to the difference in IL-8 production, the immature enterocytes expressed appreciably lower levels of specific IκB genes when compared with the mature enterocytes. Similar developmentally regulated differences in cytokine response and IκB expression were also seen in primary rat enterocytes, indicating that these observations were not peculiarities of the cell lines. Furthermore, when the level of IκBα expression was increased in the immature cell line by transfection, the flagellin-dependent IL-8 response was attenuated. Thus, we have demonstrated a previously undescribed developmental regulation of IκB expression in the intestine involved in modulating the IL-8 response to bacterial infection, which may contribute to the pathogenesis of age-specific inflammatory bowel diseases such as necrotizing enterocolitis.
Interactions of glutaredoxins, ribonucleotide reductase, and components of the DNA replication system of
Escherichia coli
Authors: Ortenberg Ron , Gon Stéphanie , Porat Amir , Beckwith Jon
Published: April 2004

A strain of
Escherichia coli
missing three members of the thioredoxin superfamily, thioredoxins 1 and 2 and glutaredoxin 1, is unable to grow, a phenotype presumed to be due to the inability of cells to reduce the essential enzyme ribonucleotide reductase. Two classes of mutations can restore growth to such a strain. First, we have isolated a collection of mutations in the gene for the protein glutaredoxin 3 that suppress the growth defect. Remarkably, all eight independent mutations alter the same amino acid, methionine-43, changing it to valine, isoleucine, or leucine. From the position of the amino acid changes and their effects, we propose that these alterations change the protein so that its properties are closer to those of glutaredoxin 1. The second means of suppressing the growth defects of the multiply mutant strain was by mutations in the DNA replication genes,
dnaA
and
dnaN
. These mutations substantially increase the expression of ribonucleotide reductase, most likely by altering the interaction of the regulatory protein DnaA with the ribonucleotide reductase promoter. Our results suggest that this increase in the concentration of ribonucleotide reductase in the cell allows more effective interaction with glutaredoxin 3, thus restoring an effective pool of deoxyribonucleotides. Our studies present direct evidence that ribonucleotide reductase is the only
essential
enzyme that requires the three reductive proteins missing in our strains. Our results also suggest an unexpected regulatory interaction between the DnaA and DnaN proteins.
A review of informal learning literature, theory and implications for practice in developing global professional competence
Authors: Conlon Thomas J.
Published: April 2004

Informal learning's roots emerged from educational philosophers John Dewey, Kurt Lewin and Mary Parker Follett to theorists Malcolm Knowles and other successive researchers. This paper explores the background and definitions of informal learning and applications to the global workplace. Informal learning's challenges are applied to developing global professional competence, including theory, practice and policy implications. The paper argues that informal learning plays a considerable role in developing professional expertise in the workplace and private life, yet believes no current theoretical model exists to balance conflicts between the role of individual and organizational benefits in a global context.
Exploiting the opportunities of Internet and multi‐channel pricing: an exploratory research
Authors: Sotgiu Francesca , Ancarani Fabio
Published: April 2004

Smart firms are not worried about the impact of the Internet on pricing, but realise that they have the unique opportunity to exploit new options and improve their marketing performance. Multi‐channel pricing is one of the most interesting opportunities firms can exploit in the digital economy. Reviews the existing literature on pricing on the Internet and on multi‐channel pricing. Presents the results of an exploratory research on price opportunities perceived by firms. Offers a picture of the possible multi‐channel options available to firms and highlights the importance of the value for and of the customer.
Designing a newe‐business model for a commercial real estate enterprise: a case study
Authors: Stavrovski Boris
Published: April 2004

A new e‐business model for implementing complex business transactions via the Internet has been created. The model involves search, negotiation, and legal closing, and its implementation, as described here, is able to: quantitatively evaluate preferences of potential customers (tenants and landlords), and define permissible search areas and allowable ranges for bargaining; search all publicly available databases and generate a statistical model of the current market situation and future tendencies as they relate to the customer's preferences; and organise interactive multi‐party negotiations pertaining to the information received, and formulate suggestions that will establish the basis for a compromise.
Phytophthora root and collar rot of alders in Bavaria: distribution, modes of spread and possible management strategies
Authors: Jung T. , Blaschke M.
Published: April 2004

A survey of symptoms of phytophthora root and collar rot of common (Alnus glutinosa) and grey alder (A. incana) in riparian and forest stands in Bavaria was conducted by the Bavarian State Forestry and river authorities. Symptoms were seen in 1041 out of 3247 forest alder stands. The majority of the affected stands (80·9%) were less than 21 years old; 46% of these young stands were growing on nonflooded sites and 92% had been planted. The riparian survey showed that symptoms were widespread along more than 50% of the river systems. Along some rivers the disease incidence exceeded 50%. The ‘alder Phytophthora’ was recovered from 166 of 185 riparian and forest alder stands with symptoms. In 58 of the 60 rivers and streams investigated in detail, the source of inoculum was traced back to infested young alder plantations growing on the river banks or on forest sites that drain into the rivers. Once introduced to a river system, the ‘alder Phytophthora’ infects alders downstream. Baiting tests showed that the ‘alder Phytophthora’ was present in rootstocks of alders from three out of four nurseries which regularly bought in alder plants for re‐sale, but not in rootstocks from four nurseries that grew their own alders from seed. In addition, the infected nurseries used water from infested water courses for irrigation. The Bavarian State Ministry for Agriculture and Forestry has developed a code of practice for producing healthy alder plants in forest nurseries. This includes a 3‐year fallow period between bare‐rooted alder crops because of poor survival of the ‘alder Phytophthora’ in soil.
Building urban Christian communities: sermons on local saints in the Eusebius Gallicanus collection
Authors: Bailey Lisa
Published: April 2004

This article uses the sermons in the anonymous collection known as the Eusebius Gallicanus to explore the ways in which preachers in fifth‐century Gaul tried to build urban Christian communities, focusing particularly on the subset of sermons which deal with local saints. In these sermons preachers adapt a tradition of Christian language and thought to the specific circumstances they faced. They seize the opportunity provided by their subject matter to evoke a vision which is urban, localized, and which stands in contrast to more ‘universal’ conceptions of Christian community.
The importance of the emperor: Lothar I and the Frankish civil war, 840–843
Authors: Screen Elina
Published: April 2004

Lothar I's perspective on the Frankish civil war has not previously been explored. Close analysis of the distribution and wording of the most significant body of evidence produced by Lothar's circle, his charters, casts new light on the politics of the civil war. The imperial title and questions of legitimate inheritance emerge as factors of crucial importance, which shape not only Lothar's self‐presentation in the charters, but also Nithard's influential account of the war, and negative portrayal of Lothar.
Tale of Bygone Years: theRussian Primary Chronicleas a family chronicle
Authors: Rukavishnikov Alexandr
Published: April 2004

This paper aims to develop a new approach to the investigation of the oldest Russian historical text, theTale of Bygone YearsorRussian Primary Chronicle. The purpose of this study is to examine methods by which the chronicler constructed the Riurikid princely dynasty from legendary forefathers to the author's own time. How did the contemporary political situation at the beginning of the twelfth century influence the presentation of the Riurikids of the ninth and tenth centuries? What was the place of oral traditions within the work? How did the ideology of princely power interact with the presentation of family and kinship?
Early exhumation of the collisional orogen and concurrent infill of foredeep basins in the Miocene Eurasian–Okhotsk Plate boundary, central Hokkaido, Japan: Inferences from K–Ar dating of granitoid clasts
Authors: Kawakami Gentaro , Arita Kazunori , Okada Toshinori , Itaya Tetsumaru
Published: April 2004

Abstract  Thick Middle (–Upper) Miocene turbiditic deposits filled very deep and narrow foredeep basins formed in the western margin of the Hidaka collision zone in central Hokkaido. Cobble‐ to boulder‐sized clasts of eight monzogranites and a single granodiorite in the Kawabata Formation in the Yubari Mountains area yielded biotite K–Ar ages of 44.4 ± 1.0 to 45.4 ± 1.0 Ma and 42.8 ± 1.1 Ma, respectively. Major elemental compositions of the clasts all fall in the field of S‐type granite on an NK/A (Na2O + K2O/Al2O3 in molecule) versus A/CNK (Al2O3/CaO + Na2O + K2O in molecule) diagram, verifying their peraluminous granite character (aluminium saturation index (ASI): 1.12–1.19). These geochronological and petrographical features indicate that the granitoid clasts in the Kawabata Formation correlate with Eocene granitic plutons in the northeastern Hidaka Belt, specifically the Uttsudake (43 Ma) and Monbetsu (42 Ma) plutons. Foredeep basins are flexural depressions developed at the frontal side of thickened thrust wedges. The results presented here suggest that deposition of the Middle Miocene turbidites was coeval with rapid westward up‐thrusting and exhumation of the Hidaka Belt. This early mountain building may have occurred in response to thrusting in the Tertiary fold‐and‐thrust system of central Hokkaido.
A Sequence-Independent Strategy for Detection and Cloning of Circular DNA Virus Genomes by Using Multiply Primed Rolling-Circle Amplification
Authors: Rector Annabel , Tachezy Ruth , Van Ranst Marc
Published: April 2004

The discovery of novel viruses has often been accomplished by using hybridization-based methods that necessitate the availability of a previously characterized virus genome probe or knowledge of the viral nucleotide sequence to construct consensus or degenerate PCR primers. In their natural replication cycle, certain viruses employ a rolling-circle mechanism to propagate their circular genomes, and multiply primed rolling-circle amplification (RCA) with φ29 DNA polymerase has recently been applied in the amplification of circular plasmid vectors used in cloning. We employed an isothermal RCA protocol that uses random hexamer primers to amplify the complete genomes of papillomaviruses without the need for prior knowledge of their DNA sequences. We optimized this RCA technique with extracted human papillomavirus type 16 (HPV-16) DNA from W12 cells, using a real-time quantitative PCR assay to determine amplification efficiency, and obtained a 2.4 × 10
4
-fold increase in HPV-16 DNA concentration. We were able to clone the complete HPV-16 genome from this multiply primed RCA product. The optimized protocol was subsequently applied to a bovine fibropapillomatous wart tissue sample. Whereas no papillomavirus DNA could be detected by restriction enzyme digestion of the original sample, multiply primed RCA enabled us to obtain a sufficient amount of papillomavirus DNA for restriction enzyme analysis, cloning, and subsequent sequencing of a novel variant of bovine papillomavirus type 1. The multiply primed RCA method allows the discovery of previously unknown papillomaviruses, and possibly also other circular DNA viruses, without a priori sequence information.
Wide Variations in Herpes Simplex Virus Type 1 Inoculum Dose and Latency-Associated Transcript Expression Phenotype Do Not Alter the Establishment of Latency in the Rabbit Eye Model
Authors: O'Neil J. E. , Loutsch J. M. , Aguilar J. S. , Hill J. M. , Wagner E. K. , Bloom D. C.
Published: April 2004

The latency-associated transcript (LAT) is required for efficient reactivation of herpes simplex virus type 1 from latent infection in the rabbit eye model, but LAT's mechanism of action is unknown. In addition to reactivation, the LAT region seems to correspond to multiple functions, with some LAT deletion mutants exhibiting increased virulence, increased neuronal death, and restricted establishment of latency. While a LAT promoter deletion mutant (17ΔPst) seems to be primarily restricted in reactivation in the rabbit, subtle effects on virulence or the establishment of latency cannot be precluded at the normal high levels of virus inoculum used in the rabbit model. Since such additional LAT phenotypes may be more evident with lower doses of virus, we evaluated the influence of initial viral inoculum and LAT expression on the progression of acute infection and the establishment of latency. We have assayed both virus recovery rates and viral genome loads in rabbit corneas and trigeminal ganglia. Our results show that (i) in the corneas and trigeminal ganglia, the maximum amount of virus present during acute infection is independent of the LAT genotype and inoculum dose, although greater viral yields are obtained earlier with higher inoculum doses, and (ii) the range in numbers of latent genomes detected in the ganglia is independent of the inoculum dose and the LAT genotype and therefore no difference in establishment of latency is observed.
Interaction between Human Immunodeficiency Virus Type 1 Reverse Transcriptase and Integrase Proteins
Authors: Hehl Eric A. , Joshi Pheroze , Kalpana Ganjam V. , Prasad Vinayaka R.
Published: April 2004

Reverse transcriptase (RT) and integrase (IN) are two key catalytic enzymes encoded by all retroviruses. It has been shown that a specific interaction occurs between the human immunodeficiency virus type 1 (HIV-1) RT and IN proteins (X. Wu, H. Liu, H. Xiao, J. A. Conway, E. Hehl, G. V. Kalpana, V. R. Prasad, and J. C. Kappes, J. Virol. 73:2126-2135, 1999). We have now further examined this interaction to map the binding domains and to determine the effects of interaction on enzyme function. Using recombinant purified proteins, we have found that both a HIV-1 RT heterodimer (p66/p51) and its individual subunits, p51 and p66, are able to bind to HIV-1 IN. An oligomerization-defective mutant of IN, V260E, retained the ability to bind to RT, showing that IN oligomerization may not be required for interaction. Furthermore, we report that the C-terminal domain of IN, but not the N-terminal zinc-binding domain or the catalytic core domain, was able to bind to heterodimeric RT. Deletion analysis to map the IN-binding domain on RT revealed two separate IN-interacting domains: the fingers-palm domain and the carboxy-terminal half of the connection subdomain. The carboxy-terminal domain of IN alone retained its interaction with both the fingers-palm and the connection-RNase H fragments of RT, but not with the half connection-RNase H fragment. This interaction was not bridged by nucleic acids, as shown by micrococcal nuclease treatment of the proteins prior to the binding reaction. The influences of IN and RT on each other's activities were investigated by performing RT processivity and IN-mediated 3′ processing and joining reactions in the presence of both proteins. Our results suggest that, while IN had no influence on RT processivity, RT stimulated the IN-mediated strand transfer reaction in a dose-dependent manner up to 155-fold. Thus, a functional interaction between these two viral enzymes may occur during viral replication.
Migration ofAntigen-Specific T Cells Away from CXCR4-Binding Human ImmunodeficiencyVirus Type 1gp120
Authors: Brainard Diana M. , Tharp William G. , Granado Elva , Miller Nicholas , Trocha Alicja K. , Ren Xiang-Hui , Conrad Brian , Terwilliger Ernest F. , Wyatt Richard , Walker Bruce D. , Poznansky Mark C.
Published: April 2004

Cell-mediated immunity depends in part on appropriate migration and localization of cytotoxic T lymphocytes (CTL), a process regulated by chemokines and adhesion molecules. Many viruses, including human immunodeficiency virus type 1 (HIV-1), encode chemotactically active proteins, suggesting that dysregulation of immune cell trafficking may be a strategy for immune evasion. HIV-1 gp120, a retroviral envelope protein, has been shown to act as a T-cell chemoattractant via binding to the chemokine receptor and HIV-1 coreceptor CXCR4. We have previously shown that T cells move away from the chemokine stromal cell-derived factor 1 (SDF-1) in a concentration-dependent and CXCR4 receptor-mediated manner. Here, we demonstrate that CXCR4-binding HIV-1 X4 gp120 causes the movement of T cells, including HIV-specific CTL, away from high concentrations of the viral protein. This migratory response is CD4 independent and inhibited by anti-CXCR4 antibodies and pertussis toxin. Additionally, the expression of X4 gp120 by target cells reduces CTL efficacy in an in vitro system designed to account for the effect of cell migration on the ability of CTL to kill their target cells. Recombinant X4 gp120 also significantly reduced antigen-specific T-cell infiltration at a site of antigen challenge in vivo. The repellant activity of HIV-1 gp120 on immune cells in vitro and in vivo was shown to be dependent on the V2 and V3 loops of HIV-1 gp120. These data suggest that the active movement of T cells away from CXCR4-binding HIV-1 gp120, which we previously termed fugetaxis, may provide a novel mechanism by which HIV-1 evades challenge by immune effector cells in vivo.
Role of Transmembrane Domain and Cytoplasmic Tail Amino Acid Sequences of Influenza A Virus Neuraminidase in Raft Association and Virus Budding
Authors: Barman Subrata , Adhikary Lopa , Chakrabarti Alok K. , Bernas Carl , Kawaoka Yoshihiro , Nayak Debi P.
Published: April 2004

Influenza virus neuraminidase (NA), a type II transmembrane glycoprotein, possesses receptor-destroying activity and thereby facilitates virus release from the cell surface. Among the influenza A viruses, both the cytoplasmic tail (CT) and transmembrane domain (TMD) amino acid sequences of NA are highly conserved, yet their function(s) in virus biology remains unknown. To investigate the role of amino acid sequences of the CT and TMD on the virus life cycle, we systematically mutagenized the entire CT and TMD of NA by converting two to five contiguous amino acids to alanine. In addition, we also made two chimeric NA by replacing the CT proximal one-third amino acids of the NA TMD [NA(1T2N)NA] and the entire NA TMD (NATRNA) with that of human transferrin receptor (TR) (a type II transmembrane glycoprotein). We rescued transfectant mutant viruses by reverse genetics and examined their phenotypes. Our results show that all mutated and chimeric NAs could be rescued into transfectant viruses. Different mutants showed pleiotropic effects on virus growth and replication. Some mutants (NA2A5, NA3A7, and NA4A10) had little effect on virus growth while others (NA3A2, NA5A27, and NA5A31) produced about 50- to 100-fold-less infectious virus and still some others (NA5A14, NA4A19, and NA4A23) exhibited an intermediate phenotype. In general, mutations towards the ectodomain-proximal sequences of TMD progressively caused reduction in NA enzyme activity, affected lipid raft association, and attenuated virus growth. Electron microscopic analysis showed that these mutant viruses remained aggregated and bound to infected cell surfaces and could be released from the infected cells by bacterial NA treatment. Moreover, viruses containing mutations in the extreme N terminus of the CT (NA3A2) as well as chimeric NA containing the TMD replaced partially [NA(1T2N)NA] or fully (NATRNA) with TR TMD caused reduction in virus growth and exhibited the morphological phenotype of elongated particles. These results show that although the sequences of NA CT and TMD per se are not absolutely essential for the virus life cycle, specific amino acid sequences play a critical role in providing structural stability, enzyme activity, and lipid raft association of NA. In addition, aberrant morphogenesis including elongated particle formation of some mutant viruses indicates the involvement of NA in virus morphogenesis and budding.