bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel approach for calculating correlation energy based on the two‐electron density matrix formalism
Authors: Bálint Imre , Dezső Gergely , Gyémánt Iván
Published: August 2002

The two‐particle density matrix contains all information which is “readable” by one‐ and two‐particle operators. This work discusses the building of a two‐electron density matrix, which is perfectly N‐representable by construction. The 2‐matrix of a pure quantum state is obtained without the intermediate determination of the wave function. The procedure is illustrated by computations on atomic and small molecular systems. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 84: 32–38, 2001
A fresh look at the computation of spherically averaged electron momentum densities for wave functions built from Gaussian‐type functions
Authors: Thakkar Ajit J. , Sharma Bhawani S.
Published: August 2002

A new method for deriving the spherical average of the product of the Fourier transforms of two Gaussians is described. The method generates the result in terms of a few spherical Bessel functions leading to expressions that are much more compact than those in the literature. These integrals are required in the computation of spherically averaged electron momentum densities, and rotationally averaged X‐ray and high‐energy electron scattering crossections. All integrals needed for spherically averaged momentum densities are tabulated for s, p, d, and f‐type Gaussians. As an illustration of the method, we apply it to calculate spherically averaged electron momentum densities and their moments for H2O. The calculations are performed at the Hartree–Fock and 2nd‐ and 4th‐order Møller–Plesset perturbation theory levels with the aug‐cc‐pVDZ and aug‐cc‐pVTZ basis sets. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Electronic density‐matrix algorithm for nonadiabatic couplings in molecular dynamics simulations
Authors: Tommasini M. , Chernyak V. , Mukamel S.
Published: August 2002

Closed expressions for nonadiabatic couplings are derived using the collective electronic oscillators (CEO) algorithm based on the time‐dependent Hartree–Fock equations. Analytic derivatives allow the calculation of transition density matrices and potential surfaces at arbitrary nuclear geometries using a molecular dynamics trajectory that only requires a CEO calculation at a single configuration. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Can an independent‐electron model be exact for an N‐electron system?
Authors: Nesbet R. K.
Published: August 2002

Density functional theory (DFT) is commonly understood to provide an exact independent‐electron model of N‐electron ground states, using only local potential functions. It has recently been shown that restriction to local potentials leads to inconsistencies in the Thomas–Fermi theory, in the Hartree–Fock model of DFT (local exchange potential), and in linear response theory (the exchange response kernel differs from the exact linear exchange operator derived in 1930 by Dirac). It is shown here that by extending the theory to a more general orbital functional theory (OFT) these inconsistencies or paradoxes can be resolved. An orbital‐functional representation of correlation energy leads to a formally exact theory of stationary states and of linear response. The theory is free of self‐interaction and implies physically meaningful one‐electron energies, consistent with Landau quasiparticles in many‐body theory. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Principal component analysis of mass spectra of peptides generated from the tryptic digestion of protein mixtures
Authors: Bryant Duncan K. , Monté Soraya , Man Wai J. , Kramer Kerstin , Bugelski Peter , Neville William , White Ian R. , Camilleri Patrick
Published: August 2002

Principal component analysis (PCA) has been used to analyse mass spectral peptide profiles obtained from the enzymatic digestion of standard protein mixtures. Scores and loadings plots clearly revealed peptide fragments that differentiated one protein mixture from another. Peptide map search results identified with a high degree of certainty any additional proteins in these mixtures. As a proof‐of‐concept this methodology was applied to hepatic protein mixtures obtained from rats treated with two hepatotoxic compounds: methapyriline and SB‐219994. Liver proteins were extracted, pre‐separated by one‐dimensional polyacrylamide gel electrophoresis, subjected to tryptic digestion and analysed by mass spectrometry. Two up‐regulated proteins, glutathione S‐transferase with methapyrilene and peroxisomal bifunctional enzyme with SB‐219994, were identified in this manner. Copyright © 2001 John Wiley & Sons, Ltd.
Characterizing the fragmentation of 2,5‐bis (4‐amidinophenyl)furan‐bis‐O‐methylamidoxime and selected metabolites using ion trap mass spectrometry
Authors: Zhou Lian , Voyksner Robert D. , Thakker Dhiren R. , Stephens Chad E. , Anbazhagan Mariappan , Boykin David W. , Hall James E. , Tidwell Richard R.
Published: August 2002

A novel prodrug [2,5‐bis(4‐amidinophenyl)furan‐bis‐O‐methylamidoxime (DB289)] of the promising antimicrobial agent, 2,5‐bis(4‐amidinophenyl)furan (DB75), has excellent oral activity. It is currently undergoing phase II clinical evaluation as an orally administered drug candidate against African trypanosomiasis and Pneumocystis carinii pneumonia. The sequential product ion (MSn) fragmentations of DB289 and selected metabolites were characterized using ion trap mass spectrometry with electrospray ionization. An unusual homolytic bond cleavage, formation of an odd‐electron ion from an even‐electron ion with the loss of a radical, was commonly seen in the fragmentation patterns of DB289 and its metabolites. Both O‐ethyl and N‐methyl homologues of DB289 were utilized to confirm this fragmentation pathway. The labile hydrogen atoms in DB289 are readily exchanged with deuterium atoms in the solvent containing deuterium oxide (D2O) instead of water. The mass shift patterns displayed in the product ion spectra of DB289 in D2O proved useful in verifying the fragmentation pathway. Octadeuterated DB289 and DB75 (d‐labeling on the diphenyl rings) showed unequivocally that the diphenylfuran moiety is not involved in the fragmentation. The fragmentation pathways uncovered in this work will facilitate structural characterization of all the metabolites produced in the metabolic activation of DB289. Copyright © 2002 John Wiley & Sons, Ltd.
Cost Evaluation for Selected Remediation Technologies
Authors: Kingscott John , Weisman Richard J.
Published: August 2002

Relatively little data are available to document the historical cost for using common remediation
technologies, and site managers often must rely on information from technology vendors and predictive models,
which may not accurately reflect the experiences of previous technology users. To help address these concerns,
the U.S. Environmental Protection Agency (EPA) conducted an evaluation of data on historical costs of
common remediation technologies. Cost curves were developed for four technologies, showing the relationship
between cost for remediation and quantity of material treated. Although costs are known to be highly
site‐specific and affected by many factors, the curves are useful in illustrating the variability of
historical costs and the economies of scale for treating relatively large quantities of material. © 2002
Wiley Periodicals, Inc.
Primate hepatitis B viruses – genetic diversity, geography and evolution
Authors: Robertson Betty H. , Margolis Harold S.
Published: August 2002

There are six well characterised genotypes (A–F) of human hepatitis B virus that have distinct geographic ranges which generally relate to chronic HBV infection. A seventh human genotype (G) has recently been described, but there is limited information on ethnic and geographic distribution. Despite the fact that early studies indicated that HBV antigens were present in other primates, the prevailing dogma that HBV was a human disease precluded alternative explanations. Within the past 5 years, hepatitis B viruses have been characterised from all the Old World great apes (orangutan, gibbons, gorillas and chimpanzees) and from a New World woolly monkey. Each group of non‐human primates appears to have a distinct strain of hepatitis B virus that can be distinguished from human sequences based upon the nucleotide sequence and selected amino acid changes in the viral proteins. The woolly monkey HBV is most divergent from other primate and human sequences, while the great ape HBV sequences cluster together with separate branches for each group. Published in 2002 by John Wiley & Sons, Ltd.
Potential of combined spaceborne infrared and microwave radiometry for near real‐time rainfall attenuation monitoring along earth‐satellite links
Authors: Marzano Frank S. , Turk Joseph F. , Ciotti Piero , Michele Sabatino Di , Pierdicca Nazzareno
Published: August 2002

The objective of this paper is to investigate how spaceborne remote sensors, and their derived products, can be exploited to optimize the performances of a satellite communication system in the presence of precipitating clouds along the path. The complementarity between sun‐synchronous microwave (MW) and geo‐stationary infrared (IR) radiometry for monitoring the earth's atmosphere is discussed and their potential as a rain detection system within near real‐time countermeasure techniques for earth‐satellite microwave links is analysed. A general approach, consisting in estimating rainfall intensity and attenuation by polar‐orbiting microwave radiometers and temporally tracking the rainfall areas by geo‐stationary infrared radiometers, is delineated. Multiple regression algorithms for predicting rainfall attenuation from spaceborne brightness temperatures and from surface rainrate, trained by radiative transfer and cloud models, are illustrated. A maximum likelihood technique is delineated to discriminate stratiform and convective rainfall from spaceborne brightness temperatures. The differences among attenuation estimates derived from layered raining‐cloud structures with respect to those obtained from simple rain slabs, as recommended by ITU‐R, are also quantified. A test of the proposed attenuation prediction methods is performed using raingage and Italsat data acquired in Spino d'Adda (Italy) during 1994. A description of the statistical method, based on the probability matching technique, adopted to combine MW and IR data for retrieving and tracking precipitating cloud systems in terms of path attenuation and accumulated rain at ground is finally provided together with its application to a case study over the Mediterranean area during October 1998. Copyright © 2001 John Wiley & Sons, Ltd.
Comparing expectations to actual events: the post mortem of a Y2K analysis
Authors: Backus George , Schwein Michael T. , Johnson Scott T. , Walker Robert J.
Published: August 2002

This article reviews an analysis performed for a “high‐tech” company in mid‐1998 to evaluate the potential impacts of Y2K on the company's performance. The authors are no longer directly associated with the company and the results have been restated to protect the company's identity. The model performed better than existing in‐house tools, but inconsistency tests uncovered “insider” information that needed to be included in the model. The final scenarios and associated recommendations indicated response requirements incompatible with the time constants of information flows within the company. Like the Titanic moving toward the iceberg, it was already too late for the company to do much more than hope that fate would be kind. The causal dynamics left little to fate. A “validated” model often becomes part of the problem and the feedback (decision‐making) system it is attempting to influence. To have a successful impact, consultants may need to give up their supposed objective position and personally engage themselves in the risk‐ridden, internal, political processes of the client organization. Copyright © 2001 John Wiley & Sons, Ltd.
Comparison of the Tougaard, ARXPS, RBS and ellipsometry methods to determine the thickness of thin SiO2 layers
Authors: Semak B. S. , van der Marel C. , Tougaard S.
Published: August 2002

The Tougaard and angle‐resolved x‐ray photoelectron spectroscopy (ARXPS) methods were compared with ellipsometry and Rutherford backscattering (RBS) for their ability to determine the amount of SiO2 on an Si substrate. The Tougaard and ARXPS methods give generally consistent results (root‐mean‐square deviation ∼12%), whereas the deviation between the other techniques is significantly larger (∼30–40%). The Tougaard method gives consistent results for all angles of emission θ ≤ 60°. It is found also that the amount of SiO2 determined by the two methods depends approximately linearly on the inelastic mean free path. The ARXPS method also depends on the accuracy with which one can separate the peak area of the bulk and the oxide part of the peaks. The correction for elastic scattering in the ARXPS method gives a reduction of only 5–7% in the determined amount of SiO2. Copyright © 2002 John Wiley & Sons, Ltd.
Interlaboratory study on the degradation of poly(vinyl chloride), nitrocellulose and poly(tetrafluoroethylene) by x‐rays in XPS
Authors: Yoshihara K. , Tanaka A.
Published: August 2002

In XPS, it is often observed that the x‐ray flux causes changes in the surface structure and chemistry in the surface region of organic materials. However, at present, there is no standard guide to estimate the relationship between the degradation rate and x‐ray source flux. To investigate this relationship, we conducted an interlaboratory study on the degradation of three kinds of polymers—poly(vinyl chloride) (PVC), nitrocellulose + cellulose acetate (NC + CA) and poly(tetrafluoroethylene) (PTFE)—by x‐ray irradiation as Project A5 of the VAMAS Technical Working Area 2 on Surface Analysis; 40 laboratories participated in this study.

From this interlaboratory study, it was concluded that the rate constant of the degradation for PVC and NC+CA could be obtained from the peak intensity changes of Cl 2p and N 1s photoelectrons, respectively, assuming first‐order reaction with photons. There is a fairly good correlation between the rate constants of the degradation for PVC and that of NC + CA, and, if the analysis was carried out using achromatic x‐ray sources only, a better correlation was obtained than that by a monochromatic source. Therefore, PVC and NC + CA will be good specimens for the indicators of x‐ray source flux. The degradation behaviour of PTFE is more complicated and does not follow a first‐order reaction. The rate constant of the degradation for PTFE obtained at the initial stage of the irradiation was compared with that of NC + CA. However, there is a poor correlation between them. Copyright © 2002 John Wiley & Sons, Ltd.
Estimation of inelastic mean free paths for polymers and other organic materials: use of quantitative structure–property relationships
Authors: Cumpson Peter J.
Published: August 2002

Inelastic mean free path values are needed for quantitative XPS analysis of a range of important polymers and other organic materials. Measured reference data are limited, although some semi‐empirical equations to estimate IMFP are available. Existing estimation methods often require values for such quantities as the bandgap (in electron‐volts) or the density, for which accurate measurements may not be available.

Here we develop a scheme for estimation of the IMFP that can be applied across a range of organic structures for kinetic energies of ∼200–2000 eV. This involves a quantitative structure–property relationship (QSPR), which allows the IMFP to be estimated for any organic material from its structural formula alone, either via a straightforward calculation on paper or instantly using one of a number of commercial molecular‐modelling software packages. The accuracy of this IMFP estimate is better than existing methods, such as the TPP‐2M equation for organic materials. In the majority of analytical problems involving surface analysis in chemistry or biochemistry, the structural formula of the organic material is known or can be conjectured with reasonable confidence, so that the approach described here is more widely applicable in practise and likely to be more accurate than previous methods for estimating the IMFP in organic materials. © Crown Copyright 2001 Reproduced by permission of the Controller of HMSO.
Comparison of smoothing techniques for CD4 data in a Markov model with states defined by CD4: an example on the estimation of the HIV incubation time distribution
Authors: Sypsa V. , Touloumi G. , Kenward M. , Karafoulidou A. , Hatzakis A.
Published: August 2002

Multi‐state models defined in terms of CD4 counts are useful for modelling HIV disease progression. A Markov model with six progressive CD4‐based states and an absorbing state (AIDS) was used to estimate the cumulative probability of progressing to AIDS in 158 HIV‐1 infected haemophiliacs with known seroconversion (SC) dates. A problem arising in such analysis is how to define CD4‐based states, since this marker is subject to measurement error and short timescale variability. Four approaches were used: no smoothing, ad hoc smoothing (to move to a later/previous state two consecutive measurements to later/previous states are needed), kernel smoothing and random effects (RE) models. The estimates were compared with the Kaplan–Meier estimate based solely on data concerning time to AIDS. There was an apparent lack of agreement between the Kaplan–Meier and the ‘no smoothing’ estimate. With the exception of the ‘no smoothing’ method, ‘ad hoc’, kernel and RE estimates fell within the range of the 95 per cent CIs of the Kaplan–Meier curve. Simulations demonstrated that the use of raw CD4 counts provides overestimated transition intensities. Compared to the kernel method, ad hoc is easier to implement and overcomes the problem of the choice of bandwidth. The RE approach leads to simple models, since it usually results in very few transitions to previous states, and can handle individuals with sparse data by smoothing their predictions towards the population mean. Ad hoc was the method that performed better, in terms of bias, than the other smoothing approaches. Copyright © 2001 John Wiley & Sons, Ltd.
Experimental evaluation of hypertext access structures
Authors: Koskinen Jussi
Published: August 2002

Transient hypertextual access structures (THASs) are temporary graphs formed automatically on the basis of the situation‐dependent information needs of software engineers. The approach is implemented in the HyperSoft system, which is a hypertext‐based software maintenance support tool. THASs highlight the relevant parts of the program and enable nonlinear browsing between them. The system also supports various graphical views whose elements are linked to the program text. This paper describes the effects of using these hypertextual structures in two separate experiments. The subjects of both experiments were computer science students (total $N=70$). In both experiments, the subjects performed a series of sample information accesses from a C program. HyperSoft and conventional text browsing and searching were compared. The results from the two experiments are well in line with our hypothesis of the usefulness of the approach and with each other. The results indicate better task performance while using THASs as compared to using the information seeking capabilities of a conventional compiler environment. The difference is statistically significant ($p<0.001$). Copyright © 2002 John Wiley & Sons, Ltd.
Pointing towards some superior metaphysics, ontology and epistemology
Authors: Tsagdis Dimitrios
Published: August 2002

Gerard de Zeeuw's conception of scientific research as an evolving organized activity that aims to improve upon observation is employed in this paper in an attempt to help contemporary users and producers of scientific research and its outcomes in ‘stepping out’ of some major generic metaphysical, ontological and epistemological difficulties and see for themselves (e.g. better) how (a migration to) the metaphysics, ontology and epistemology proposed in this paper can be of help in resolving such difficulties. Copyright © 2002 John Wiley & Sons, Ltd.
Laws of geometric systems
Authors: McNamara Curt
Published: August 2002

In Synergetics, Buckminster Fuller defined a consistent approach to modeling Universe as spatial systems composed of events and relations. This paper will summarize the methodology and present the system properties (or laws) that are an outgrowth of this approach. Copyright © 2001 International Society for the Systems Sciences.
Demonstration of competition between endogenous dopamine and [11C]raclopride binding in in vitro brain slices using a dynamic autoradiography technique
Authors: Sasaki Toru , Ishiwata Kiichi , Murata Tetsuhito , Senda Michio
Published: August 2002

To elucidate the mechanism of in vivo binding competition between radioligand and endogenously released transmitter, we examined the influence of depolarization‐induced dopamine (DA) release on [11C]raclopride‐specific binding to D2 receptors in slices of living brain tissues using dynamic positron autoradiography. Rat brain slices were incubated in a chamber with [11C]raclopride in oxygenated medium at 34°C for 150 min. Two‐dimensional images of radioactivity in the slices were recorded on a storage phosphor screen and dynamic changes were measured. When the brain slices were exposed to the depolarization agents (25 mM K+, 50 mM K+, and 20 μM veratridine), the percentage inhibition of striatal [11C]raclopride‐specific binding was 22 ± 4%, 44 ± 8% and 54 ± 7% of the control, respectively. The percentage inhibition of [11C]raclopride‐specific binding during each depolarization treatment agreed proportionally with the amount of DA released into the medium. However, preexposure of brain slices to the same depolarization treatment (50 mM K+) did not affect the [11C]raclopride‐specific binding, suggesting that the reduction in receptor density and/or affinity was not involved in the decrease of [11C]raclopride‐specific binding. [11C]Raclopride‐specific binding decreased dose‐dependently in the presence of exogenously added DA (range 0.005–3mM). The synaptic DA concentration during each depolarization treatment estimated using three different methods.

These results suggest that the decrease of [11C]raclopride‐specific binding to striatal slices following evoked DA release is due to competition between endogenous DA and raclopride. It is unlikely that changes in D2 receptor density or in affinity of the receptors for raclopride are involved. These results provide supportive evidence for in vivo binding competition between radioligand and endogenous neurotransmitter. Synapse 44:42–50, 2002. © 2002 Wiley‐Liss, Inc.
Standards‐based reform and its unintended consequences: Implications for science education within America's urban schools
Authors: Settlage John , Meadows Lee
Published: August 2002

This conceptual article examines the influence of the current standards‐based reform upon science education policies and practices within urban schools. We identify four negative yet unforeseen effects of the reform movement: undermining urban teachers' professionalism, eroding teacher–student relationships, diluting the science curriculum, and disparate instruction based on predicted individual test performance. Our awareness of these nuisances emerged from our first‐hand engagement with urban science teaching and through our collegial relationships with exemplary urban teachers. In closing, we propose mechanisms by which university‐based science educators might address these issues by assisting exemplary urban teachers to resist the reform‐induced perils and by incorporating the urban milieu as a substantive aspect of science teacher education. © 2002 John Wiley & Sons, Inc. J Res Sci Teach 39: 114‐127, 2002
Creating relevant science through urban planning and gardening
Authors: Fusco Dana
Published: August 2002

The purpose of this article is to describe a community‐based science project that was coproduced with urban teenagers and to elaborate on my understanding of what it means to create a practicing culture of science learning. This understanding will be positioned in relation to various educationally relevant discourses and research on urban science education, concluding with an exploration of these questions: In what ways did an urban planning and community gardening project help to create a learning environment in which science was relevant? To whom was science relevant and toward what ends? It is argued that in a practicing culture of science learning, science was relevant because (a) it was created from participants' concerns, interests, and experiences inside and outside science, (b) it was an ongoing process of researching and then enacting ideas, and (c) it was situated within the broader community. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 860–877, 2001
Phenytoin‐induced cleft palate: Evidence for embryonic cardiac bradyarrhythmia due to inhibition of delayed rectifier k+ channels resulting in hypoxia–reoxygenation damage
Authors: Azarbayjani Faranak , Danielsson Bengt R.
Published: August 2002

Background

Phenytoin (PHT) teratogenicity has been related to embryonic arrhythmia due to the capacity of PHT to block IK channels pharmacologically, resulting in hypoxia–reoxygenation damage. The aim of this study was to further elucidate the proposed mechanism.

Methods

Pregnant CD‐1 mice were given PHT (85 mg/kg) or saline intraperitoneally on gestational days 10–11. Embryonic heart rhythm and presence of hemorrhage in orofacial region was recorded on day 12, fetuses were examined for malformations on day 18. Embryonic heart rate was also recorded on individual days after dosing days 9–16. In addition, PHT was given at doses of 10, 25, or 85 mg/kg on day 12 for analysis of plasma concentrations.

Results

PTH‐induced bradycardia and arrhythmia in ∼20% of the embryos, 48% showed hemorrhage in the orofacial region; 39% of the fetuses had cleft palate. The region in which hemorrhages were visible in the embryo corresponded with the region where tissue deficiency (cleft palate) was visible in the fetus at term. None of the controls showed hemorrhages, dysrhythmia, or cleft palate. PHT affected embryonic heart rates on days 9–13, but not on days 14–16. Single dose administration on day 12, the most sensitive day, resulted in a dose‐dependent decrease in embryonic heart rate (12–34%). Embryonic arrhythmia occurred at 25 and 85, but not at 10 mg/kg or in the controls. Mean maternal free plasma concentrations were 6 and 14 μmol/L in the10‐ and 25‐mg/kg groups, respectively.

Conclusions

PHT‐induced cleft palate was preceded by embryonic dysrhythmia and hemorrhage in the orofacial region. Embryonic heart rhythm was phase specifically affected, as described for selective IKr channel blockers, at clinically relevant concentrations. The results support the idea that PHT teratogenicity is a consequence of pharmacologically induced dysrhythmia and hypoxia‐related damage. Teratology 63:152–160, 2001. © 2001 Wiley‐Liss, Inc.
Nurturing an ethos of community engagement
Authors: Berberet Jerry
Published: August 2002

Rising expectations of higher education, the lackluster performance of K–12 education, declining participation in American civic life, and concerns about a deteriorating community infrastructure and difficult social issues provide new scholarly opportunities through community engagement. The postmodern era requires developing new epistemologies if this scholarship of community engagement is to flower and mature.
Effects of a pre‐incubation period on the photoinduced toxicity of polycyclic aromatic hydrocarbons to the luminescent bacterium Vibrio fischeri
Authors: El‐Alawi Yousef S. , Dixon D. George , Greenberg Bruce M.
Published: August 2002

Irradiation of polycyclic aromatic hydrocarbons (PAHs) in aqueous solution with simulated solar radiation (SSR; a light source with a visible light : UV‐A : UV‐B ratio similar to that of sunlight) can greatly enhance their toxicity. Two microbial toxicity tests with Vibrio fischeri were used to investigate the effect of composition of the growth medium and pre‐incubation on the photoinduced toxicity of PAHs. The assays were a short‐term test (15 min) and long‐term test (18 h). Both assays were carried out in SSR and darkness to examine for photoinduced toxicity of PAHs. For the short‐term toxicity assay, inhibition of bacterial luminescence was measured. For the long‐term toxicity assay, both inhibition of bacterial luminescence and inhibition of growth were recorded. To broaden this test, V. fischeri cells were pre‐incubated with PAHs in medium without a carbon source (minimal medium) for 8 h to facilitate assimilation and photooxidation of the contaminants, and to prevent bacterial growth at the outset of the assay. V. fischeri was more sensitive in minimal medium than in complex medium in both the short‐ and long‐term toxicity assays. Moreover, in the long‐term assay, SSR greatly increased toxicity, especially if there was a pre‐incubation period in minimal medium. This indicates that both assimilation and photooxidation of PAHs are important to their toxicity to V. fischeri. © 2001 John Wiley & Sons, Inc. Environ Toxicol 16: 277–286, 2001
An overview of x‐ray spectrometry at research centers in Chile
Authors: Romo‐Kröger C. M. , Cornejo‐Ponce L. , Morales J. R. , Dinator M. I. , Avila M. J. , Poblete V. H. , Galvez J. , Goldschmidt A. , Trier A. , Valdes J. , Rojas C. M. , Cantillano M. E. , Vera R. , Figueroa R. , Garcia M.
Published: August 2002

Different procedures have been used to develop x‐ray fluorescence spectroscopy in Chile. In this paper we describe those groups doing basic or applied scientific research, mainly associated with units at universities and research centers. The techniques are PIXE, common XRF, XRF excited with gamma sources, x‐ray emission from an electron microprobe and the total reflection technique. Historical aspects and experimental features are mentioned. Theoretical and methodological projects are also described. Finally, the wide field of applications of XRF in Chile is presented. Copyright © 2002 John Wiley & Sons, Ltd.
Re‐study of Gastric Cancer: Analysis of Outcome
Authors: Samson Prudencio S. , Escovidal Laurence Anthony P. , Yrastorza Samuel G. , Veneracion Ronaldo G. , Nerves Mary Yvonnette C.
Published: August 2002

Cancer of the stomach (CaS) is a dreaded disease. Fortunately, there is a decreasing incidence, except in the East. The authors did a re‐study of CaS, a widely investigated but unresolved gastrointestinal malignancy. The clinicopathologic features were evaluated to identify and measure the prognostic factors that would help the surgeon decide optimal therapy. Among 383 admitted for CaS at the East Avenue Medical Center, Quezon City, Philippines between January 1987 and December 1996, 149 underwent radical resection with curative intent. (As historical control, the experience in 136 cases was reviewed during the immediately preceding 5‐year period [1982–1986] when extended lymphadenectomy was not the standard policy.) For staging, the TNM system (tumor‐node‐metastasis) was used; to describe anatomy and surgery of stomach lymphatics, the "Japanese Rules," as modified, were adapted. Curative radical gastrectomy would include removal of the diseased stomach and regional lymphatics as defined by frozen section, including subtotal (or total) gastrectomy and "extended" D2 (with no. 12) node dissection. The clinicopathologic factors were statistically analyzed, using the accepted methods: Kaplan‐Meier for survival, univariate analysis, and multivariate analysis for independent predictors. Of the 12 risk factors assessed by univariate analysis, the following were identified by multivariate analysis as independent prognosticators of survival: (1) wall penetration; (2) node invasion; (3) TNM stage; (4) resection margin; and (5) tumor size. After curative resection, the operative mortality was 5.3% and the complications, 19.4%. The 5‐year survival was 60.4%, and recurrence, 15.4%. The results have shown that the pathology‐related factors, (1) wall penetration; (2) node invasion; and (3) resection margin, are independent prognosticators of survival, remarkably affecting outcome. In conclusion, the study supports radical gastrectomy with extended D2 lymphadenectomy for CaS as safe and effective. Survival and recurrence are a function of pathology and adequate resection; operative mortality is defined by the patient’s condition.
Tissue‐engineered Artificial Urothelium
Authors: Kawai Koji , Hattori Kazunori , Akaza Hideyuki
Published: August 2002

Abstract

Bladder wall replacement is one of the most challenging problems of urologic surgery. Various materials have been tried in experimental models, but most were not free of complications, such as leakage, infection, and stone formation. In addition, much time was needed for tissue regeneration after grafting. Bladder replacement with tissue‐engineered materials, which basically consist of autologous cells seeded on a supporting structure, represents an area of rapidly expanding interest. Recently, several investigators have reported important, successful results from in vitro systems and animal models. Here we review those experimental approaches to tissue‐engineered artificial urothelium.
Molecular and Reconstructive Urology: A Coming Together
Authors: Gardiner Robert A.
Published: August 2002

Abstract

Appreciation of the clinical utility of the protein product of kallikrein gene 3, prostate‐specific antigen (PSA), has resulted in earlier diagnosis of prostate cancer and an associated increase in the number of radical prostatectomies performed. A consequence of this change in surgical practice has been an improved understanding of sphincter anatomy and methods for sphincter preservation, which in turn have led to enhanced popularity for orthotopic urinary diversion for invasive bladder cancer. In this paper, molecular and basic science research being undertaken in an to attempt to overcome problems and limitations of the PSA/transrectal ultrasonographic biopsy approach to diagnosis are discussed. Also detailed are (1) the development of a bladder acellular matrix graft to serve as an "off the shelf" scaffold on which urothelium regenerates, (2) attempts to create a simpler, more durable bowel continence mechanism, and (3) a novel experimental technique for renal preservation based on considering the urine‐producing and urine‐directing roles of the upper tract as surgically separable entities. These research endeavors serve to illustrate how developments at the molecular and basic science levels promise to lead to further reconstructive surgical approaches when translating new developments into patient benefits during the year 2000 and beyond.
Urology in the Twenty‐first Century: Noninvasive Targeted Treatments for Urologic Malignancies
Authors: Droller Michael J.
Published: August 2002

Abstract

Notwithstanding the major advances that have been made in the treatment of bladder cancer, prostate cancer, and kidney cancer, much remains to be done if we are to translate the gains that have been made in "disease‐free survival" into actual survival in terms of quantity as well as quality of life. Indeed, we are still at an embryonic stage in understanding how cancers originate, whether defense mechanisms exist that can recognize these cancers and recognize them when they first develop, when cancers metastasize during their development, whether we have methods that are sufficiently accurate to distinguish between organ‐confined and regional extension or spread of disease, and the means by which we can identify cancers that are likely to remain organ‐confined and distinguish them from those that are predestined to metastasize. If we are to be successful in the assessment and treatment of various urologic cancers, these questions must be answered. Many new methods of assessment and treatment are being explored that in themselves may provide some answers. The present discussion focuses on these issues, on how they may lead to further understanding of the unique biology of many of these tumors, and what we may expect in terms of increased longevity and improved quality of life as we attempt to cure patients of their disease.
Future of European Urology
Authors: Debruyne Frans M.J.
Published: August 2002

Abstract

To provide the highest medical service and to maintain the most advanced research work across national boundaries, we have developed many organizations, including the European Association of Urology (EAU), the European Board of Urology (EBU), and the European Organization for Research and Treatment of Cancer (EORTC). They also have functioned to provide equal health service for all European people. In the future, superspecialization and the multidisciplinary approach are inevitable. Major changes will occur, such as prevention of stone diseases, reconstructive urology, and immune and gene therapy in oncology. Specialists will assume major roles in the urologic clinic. In those circumstances, Europe will continue to play an important role because urologists are very much involved in future strategic developments on national and Pan‐European levels.
Surgical Strategy for Large or Malignant Endocrine Pancreatic Tumors
Authors: Hellman Per , Andersson Maria , Rastad Jonas , Juhlin Claes , Karacagil Sadettin , Eriksson Barbro , Skogseid Britt , Åkerström Göran
Published: August 2002

Endocrine pancreatic tumors (EPTs) are rare but have a remarkably better prognosis than adenocarcinoma of the pancreas. Patients with EPTs benefit from surgical and medical therapy, which may alleviate symptoms due to hormonal excess and increase survival. Patients with large or malignant EPTs with infiltrative disease may suffer from local complications, including gastrointestinal bleeding and obstruction and involvement of the superior mesenteric (SMV) and portal (PV) veins. Among 31 patients with operable and large or malignant EPTs, 7 had hormone‐producing syndromes (insulin, glucagon), and 24 had clinically nonfunctioning EPTs. Surgery in these patients included vascular reconstruction of the SMV/PV (n= 4), resection of infiltrated adjacent organs (n= 5; stomach, transverse colon), or resection of concomitant liver metastases (n= 3). Four patients with conspicuously large insulinomas, and three with glucagonoma were successfully operated on with alleviation of hormonal symptoms. Among the 24 nonfunctioning EPTs, 5 patients had been explored earlier and their tumors judged inoperable due to locally invasive disease or misdiagnosis as pancreatic adenocarcinoma. The operations were performed with no mortality and low morbidity. We conclude that large and malignant EPTs with limited spread of disease may benefit from a combination of medical and surgical therapy.
Intramural Metastases from Thoracic Esophageal Cancer: Local Indicators of Advanced Disease
Authors: Nishimaki Tadashi , Suzuki Tsutomu , Tanaka Yoichi , Aizawa Kikuo , Hatakeyama Katsuyoshi , Muto Terukazu
Published: August 2002

The patterns of tumor spread and long‐term survival of patients with (n= 54) and without (n= 270) intramural metastasis from esophageal cancer were investigated after either extended radical (n= 155) or less radical (n= 169) esophagectomy. The purpose was to evaluate whether extended radical esophagectomy has an impact on the long‐term survival of patients with intramural metastases from the disease. The patients with intramural metastasis had significantly larger primary tumors (p< 0.01) and more frequent T4 tumors (p< 0.001), stage IV disease (p< 0.05), lymphatic invasion (p< 0.05), and lymph node metastasis (p< 0.01) than did those without intramural metastasis. The survival rates of patients with intramural metastases were significantly worse than those of patients without intramural metastases after resection (p< 0.001). No patient with intramural metastases survived more than 4 years after either extended or less radical esophagectomy, and there was no significant difference between the two survival curves. Therefore intramural metastases should be considered local indicators of advanced esophageal cancer, and radical esophagectomy may not be indicated for patients with intramural metastasis from the disease.
Helical Computed Tomography for Abdominal Imaging
Authors: Krasny Robert M. , Lu David S.K.
Published: August 2002

Significant technologic advances have taken place in computed tomography (CT). Current‐generation conventional CT scanners are able to image a slice of tissue in as little as 2 to 3 seconds and can acquire several consecutive images. Although it is a substantial improvement from the CT of 5 years ago, there remain practical limits to the utility of conventional CT imaging within the abdomen. Recently, a new type of CT gantry design (“slip‐ring”) and faster computers have contributed to the development of a new generation of CT scanners, the “helical” or “spiral” CT scanners.
Modified Sujura Operation: Long‐Term Results
Authors: Battaglia G. , Ancona E. , Patarnello E. , Morbin T. , Anselmino M. , Peracchia A.
Published: August 2002

From January 1980 to January 1986 a total of 93 patients with portal hypertension (59 males, 34 females; average age 51.5 years) underwent the modified Sujura’s operation. All patients presented with esophageal varices during the preoperative endoscopic workup. Child’s risk category was A in 6 patients and B in the remaining 87. Our technique consisted of: (1) devascularization of the upper half of the gastric corpus and fundus; (2) devascularization of the last 10 to 12 cm of the thoracic esophagus; (3) pyloric divulsion; (4) resection and anastomosis at the esophagogastric junction; and (5) antireflux fundoplication. In the presence of severe hypersplenism we added splenectomy. The surgical approach was through a xiphoumbilical laparotomy, extended to the left side when splenectomy was anticipated. We observed 19.8% early mortality (10% with elective procedures and 27.2% with emergency operations) and two cases of early rebleeding from acute mucosal lesions. Long‐term follow‐up of 82 patients revealed 30 cases of rebleeding (36.6%). Ruptured esophageal varices occurred in 12 patients (11 were treated with endoscopic sclerotherapy), whereas in 11 patients the cause of bleeding was a hemorrhagic gastritis. Of the remaining patients, two had rebleeding from a gastric ulcer, one from gastric varices, one from duodenal varices; in three patients the source of the hemorrhage remains unknown. The survival for elective procedure patients was 59.2% at 5 years and 40.7% at 10 years.
Role of Preoperative Transcatheter Arterial Oily Chemoembolization for Resectable Hepatocellular Carcinoma
Authors: Uchida Masaaki , Kohno Hitoshi , Kubota Hirofumi , Hayashi Takafumi , Yamanoi Akira , Kimoto Takeo , Ono Takashi , Nagasue Naofumi
Published: August 2002

To clarify the effect of preoperative transcatheter arterial oily chemoembolization (TAOE) for resectable hepatocellular carcinoma (HCC) on long‐term survival after curative resection, we retrospectively evaluated 60 patients with and 68 patients without preoperative TAOE. Although there was no substantial difference in the clinical backgrounds between the two groups, the 5‐year survival rate was lower for the patients with preoperative TAOE than for those without TAOE: 24% versus 63%, respectively (p< 0.05). A worse survival rate was particularly observed for the cirrhotic patients with TAOE than for those without TAOE: 35% and 72% at 4 years, respectively (p< 0.01). As the cause of death, liver failure and gastrointestinal bleeding were more frequent in the patients with TAOE (13.3% versus 1.5%;p< 0.05). Although the TAOE seemed to retard intrahepatic recurrence during the first 1.5 years after operation (1.7% versus 10.3%;p< 0.05), the overall cancer death rate was similar between the two groups (18.3% versus 11.8%). Therefore we suggest that preoperative TAOE must not be performed for resectable HCC as a routine procedure, particularly in patients with cirrhosis. A prospective randomized trial is warranted to elucidate the merits and demerits of preoperative TAOE for surgically resectable HCC.
Parathyroid Tissue in Normocalcemic and Hypercalcemic Primary Hyperparathyroidism Recruited by Health Screening
Authors: Lundgren Ewa , Ridefelt Peter , Åkerström Göran , Ljunghall Sverker , Rastad Jonas
Published: August 2002

Parathyroid tissue from 57 women (mean age 65.5 years) with sporadic primary hyperparathyroidism (HPT) was analyzed mainly to clarify its characteristics versus tissue from those with normocalcemia. Patients were recruited by population‐based health screening of menopausal women. Analysis of three or four total serum calcium values showed normocalcemia in 16 patients (mean 2.53 mmol/L); 20 and 21 of the women were consistently (mean 2.82 mmol/L) or intermittently (mean 2.59 mmol/L) hypercalcemic, respectively. Parathyroid operation demonstrated a single adenoma in 81% of the individuals, and these lesions were most prevalent and commonly dominated by oxyphil parathyroid cells in the persistently hypercalcemic patients. Chief cell hyperplasia (two or three abnormal glands) of the nodular type was found more often in the normocalcemic patients. Total glandular weight was the smallest (mean 270 mg) among the normocalcemic women and contributed to delicate decisions with regard to the extent of resection. Immunostaining of cryosections with a monoclonal antibody recognizing a putative Ca2+sensor demonstrated variably heterogeneous down‐regulation of the recognized glycoprotein in the pathologic parathyroid glands from all the individuals. Dose–response relations for PTH release and the cytoplasmic Ca2+concentration ([Ca2+]i) were determined in Ca2+0.5–3.0 mmol/L by examining dispersed cells with radioimmunoassay and microfluorometry after fura‐2 loading, respectively. ED50 for PTH release and [Ca2+]i and the [Ca2+]i concentrations at Ca2+3.0 mmol/L were the least deranged in cells from pathologic glands of the normocalcemic patients. The findings substantiate that the abnormal parathyroid tissue of normocalcemic HPT principally is characterized by the same, albeit less extensive, morphologic and functional derangements, which consistently have been demonstrated in patients with HPT accompanied by hypercalcemia and detected clinically.
Adrenaloma: A Call for More Aggressive Management
Authors: Linos Dimitrios A. , Stylopoulos Nikolaos , Raptis Sotirios A.
Published: August 2002

We review our experience from the surgical management of 57 patients (24 males, 33 females) with a mean age of 48.5 years who underwent adrenalectomy because of the computed tomography (CT) finding of a “nonfunctioning” adrenal tumor (adrenaloma). We found that CT consistently underestimated the real histologic size of the adrenal tumor (p= 0.001). Of the 57 resected tumors, 23 were cortical adenomas, 7 myelolipomas, 8 adrenal cysts, 11 nodular hyperplasias, 2 primary adenocarcinomas, 2 metastatic carcinomas, and 4 pheochromocytomas. The mean diameter was 5.89 cm and the mean weight 114.07 g. The mean diameter of the resected primary adenocarcinomas was 3.0 cm and 4.5 cm, respectively. The operative mortality was zero and the perioperative morbidity minimal. The mean operating time was 137 minutes (range 60–240 minutes). The posterior approach had the shortest operating time and the laparoscopic approach the shortest hospital stay and the least postoperative need for narcotics. During the 6.2 years mean follow‐up period, five patients with preoperative hypertension remained normotensive, and both patients with the resected primary adenocarcinomas are alive without recurrence. We suggest a more liberal surgical approach to patients with adrenalomas because: (1) even small tumors can be malignant or potentially lethal (e.g., pheochromocytomas); (2) some tumors that appear to be nonfunctioning may in reality be functioning; and (3) other nonfunctioning tumors may, with time (and without prior notice), function. The low risk of adrenalectomy especially via the laparoscopic approach can provide an early definitive diagnosis and treatment, avoiding the cost of repeated CT scans and other studies as suggested by the currently prevailing conservative management of these tumors.