bluuebunny/crossref_metadata_2025 huggingface dataset:
Melphalan pharmacokinetics in children with malignant disease: influence of body weight, renal function, carboplatin therapy and total body irradiation
Authors: Nath Christa E. , Shaw Peter J. , Montgomery Kay , Earl John W.
Published: March 2005

Aim

To analyse the pharmacokinetics of melphalan in 52 children (0.3–18 years) and determine whether any clinical factors affect the pharmacokinetic parameters Additionally, to examine whether a test melphalan dose can predict the pharmacokinetics of a full dose, when there are 5 intervening days of carboplatin therapy.

Methods

Melphalan concentrations were measured in 14 blood samples collected from each child following doses ranging from 30 to 180 mg m−2. The pharmacokinetics were analysed with Kinetica 4.0.

Results

Children who did not have carboplatin (n = 27) had median melphalan clearance (CL) of 15.5 l h−1 m−2 (interquartile range: 12.4–19.9 l h−1 m−2) and steady state volume of distribution (Vss) of 14.9 l m−2 (interquartile range: 12.7–18.3 l m−2). Children who had carboplatin (n = 25) had 34% lower median CL (10.2 l h−1 m−2) and 18% lower median Vss (12.2 l m−2) (P < 0.001). Melphalan elimination was impaired in a separate group of three children given concomitant carboplatin and etoposide. Stepwise multiple linear regression indicated that weight, carboplatin, glomerular filtration rate (GFR) and total body irradiation (TBI) significantly affected CL, while weight and carboplatin influenced Vss. A test dose (10 mg m−2) tended to underpredict the area‐under‐the‐concentration‐vs.‐time‐curve for a full (180 mg m−2) dose in 19 individuals given carboplatin.

Conclusions

In children, melphalan CL is influenced by weight, carboplatin, TBI and GFR. Vss is influenced by weight and carboplatin.
A predictive model for exemestane pharmacokinetics/pharmacodynamics incorporating the effect of food and formulation
Authors: Valle Marta , Di Salle Enrico , Jannuzzo Maria Gabriella , Poggesi Italo , Rocchetti Maurizio , Spinelli Riccardo , Verotta Davide
Published: March 2005

Aims

Exemestane (Aromasin®) is an irreversible aromatase inactivator used for the treatment of postmenopausal women with advanced breast cancer. The objective of this study was to evaluate the effect of formulation comparing a sugar‐coated tablet (SCT) with a suspension and food on the pharmacokinetics (PK) and pharmacodynamics (PD) with respect to plasma estrone sulphate (E1S) concentrations of exemestane, using a PK/PD approach.

Methods

This was an open, three‐period, randomized, crossover study. Twelve healthy postmenopausal women received single oral doses of 25 mg exemestane as a SCT after fasting or food and as a suspension after fasting. Exemestane and E1S concentrations were determined before and up to 14 days after drug administration. Population analysis was performed in two steps: (i) a compartmental PK model was selected incorporating the effect of food and formulation; (ii) conditional on the PK model, a PD model was developed employing indirect response models. Model selection was performed using standard statistical tests. Validation and assessment of the predictive capability of the selected model was performed using real test data sets obtained from the literature.

Results

A three‐compartment model with first‐order elimination rate best described exemestane disposition (k12 0.454, k21 0.158, k13 0.174, k31 0.016 and k 0.738 h−1). Absorption was described by a mono‐exponential function [ka 2.3 (SCT after fasting), 1.1 (SCT after food) and 7.6 h−1 (suspension); lag time 0.2 h]. The PD model assumed that E1S  plasma  concentrations  are  determined  by  a  zero‐order  synthesis  rate  (6.5 pg ml−1 h−1)  and  a  first‐order  elimination  constant  (0.032 h−1).  Exemestane  inhibited E1S synthesis with a C50 value of 22.1 pg ml−1. The mean population estimates were used to simulate the administration of different doses of the drug (0.5, 1, 2.5, 5 and 25 mg day−1). The model predictions were in agreement with historical data.

Conclusions

Exemestane absorption is influenced by the formulation of the drug and by food, but its disposition is independent of both. PK differences do no translate into clinically important differences in the PD. The PK/PD model developed was able to predict successfully the response to different doses and administration schedules with respect to oestrogen suppression.
The importance of long‐distance dispersal in biodiversity conservation
Authors: Trakhtenbrot Ana , Nathan Ran , Perry Gad , Richardson David M.
Published: March 2005

Dispersal is universally considered important for biodiversity conservation. However, the significance of long‐ as opposed to short‐distance dispersal is insufficiently recognized in the conservation context. Long‐distance dispersal (LDD) events, although typically rare, are crucial to population spread and to maintenance of genetic connectivity. The main threats to global biodiversity involve excessive LDD of elements alien to ecosystems and insufficient dispersal of native species, for example, because of habitat fragmentation. In this paper, we attempt to bridge the gap in the treatment of LDD by reviewing the conservation issues for which LDD is most important. We then demonstrate how taking LDD into consideration can improve conservation management decisions.
Long‐distance dispersal research: building a network of yellow brick roads
Authors: Nathan Ran
Published: March 2005

This special issue of Diversity and Distributions presents six papers that contribute to the assembly of a general research agenda for studying long‐distance dispersal (LDD) across a variety of taxonomic groups (e.g. birds, fish, aquatic invertebrates and plants), ecosystems (e.g. terrestrial and marine ecosystems, wetlands and grasslands) and thematic fields (e.g. biological transport, marine biology, biogeochemistry and biodiversity conservation). This editorial emphasizes the need to develop a network integrating different research approaches (‘yellow brick roads’) to address the great challenge (‘finding the end of the rainbow’) of quantifying, understanding and predicting LDD and its implications. I review the key avenues for future research suggested in the special issue contributions, and stress the critical importance of properly considering the spatial and temporal scales relevant to the process and system of interests. I propose combining absolute and proportional definitions of LDD as a default practice in any investigation of LDD processes. When LDD is defined primarily by an absolute critical distance that characterizes key feature(s) of the system of interest, a quantitative assessment of the proportion of dispersal events expected to move beyond this critical threshold distance should also be provided. When LDD is defined primarily by a certain small fraction of dispersal events that travel longer than all others, an estimate of the absolute distance associated with this high percentile at the tail of the dispersal curve should also be added.
Mild hypothermia reduces expression of intercellular adhesion molecule‐1 (ICAM‐1) and the accumulation of neutrophils after acid‐induced lung injury in the rat
Authors: Kira S. , Daa T. , Kashima K. , Mori M. , Noguchi T. , Yokoyama S.
Published: March 2005

Background:  The pathophysiology of the acute phase of acid‐induced lung injury (AILI) has been elucidated. However, once acute respiratory distress syndrome (ARDS) develops, the mortality rate remains high and there is, as yet, no effective therapy. There are reports that application of mild hypothermia is an effective treatment for ARDS. In this study, we hypothesize that mild hypothermia inhibits activation of neutrophils and expression of intercellular adhesion molecule‐1 (ICAM‐1) in an injured lung. We studied the effects of mild hypothermia on the expression of ICAM‐1 and the accumulation of neutrophils after AILI in the rat.

Methods:  Male Sprague‐Dawley rats were randomly allocated to one of the four groups: control normothermic group, induced mild hypothermia group, acid‐instilled normothermic group, and acid‐instilled group with mild hypothermia. At 6 h after instillation of acid, lungs were removed to measure neutrophil activity and to detect the expression of ICAM‐1 in each group.

Results:  Oxygenation in acid‐instilled rats was significantly impaired as compared to that in non‐instilled groups, but induction of mild hypothermia gradually improved oxygenation. Expression of ICAM‐1 was enhanced in the acid‐instilled normothermic group. By contrast, no overexpression of ICAM‐1 and its mRNA was detected in the acid‐instilled hypothermic group. In addition, accumulation of neutrophils was markedly inhibited after exposure to mild hypothermia irrespective of the instillation of acid.

Conclusion:  Our data suggest mild hypothermia can inhibit the adhesion, activation, and accumulation of neutrophils during the acute phase of AILI in the rat and may have the potential to reduce ongoing inflammation of ALI or ARDS.
Treatment of elevated intracranial pressure with indomethacin: Friend or foe?
Authors: Rasmussen M.
Published: March 2005

Indomethacin has been suggested as a therapeutic tool to manage elevated intracranial pressure in patients with severe head injury and patients undergoing craniotomy for brain tumors. Indomethacin is a non‐selective cyclooxygenase inhibitor. Compared to other cyclooxygenase inhibitors indomethacin has unique effects on cerebral blood flow. Administration of indomethacin causes cerebral vasoconstriction and decreases cerebral blood flow, which elicits a decrease in intracranial pressure. The mechanism of indomethacin‐induced cerebral vasoconstriction is not completely understood and controversies exist whether indomethacin causes cerebral ischemia. The primary aims of this article were to review the existing knowledge of indomethacin's influence upon cerebral hemodynamics and elevated ICP in patients with brain pathology. Furthermore, indomethacin's mechanism of action and whether it causes cerebral ischemia are discussed.
Impact of age, follicle stimulating hormone and Johnsen's score on successful sperm retrieval by microdissection testicular sperm extraction
Authors: TSUJIMURA AKIRA , MIYAGAWA YASUSHI , TAKAO TETSUYA , FUJITA KAZUTOSHI , KOMORI KAZUHIKO , MATSUOKA YASUHIRO , TAKADA SHINGO , KOGA MINORU , TAKEYAMA MASAMI , FUJIOKA HIDEKI , MATSUMIYA KIYOMI , OKUYAMA AKIHIKO
Published: March 2005

Background:  The spermatozoa retrieval rate achieved by microdissection testicular sperm extraction (TESE) for patients with non‐obstructive azoospermia is still approximately 50%, despite technical advances. Predicting a successful outcome is important to avoid unnecessary surgery. A study was conducted to determine a method for calculating the predicted probability of successful microdissection TESE.

Methods:  Testicular spermatozoa were retrieved in 41 of 100 patients by microdissection TESE. Ten clinical factors were examined in the search for an optimal logistic model for predicting a good outcome. Once the best delimiting value was established, sensitivity and specificity were calculated.

Results:  Patient age, serum follicle stimulating hormone (FSH) concentration and Johnsen's score (JS) were shown to be influential factors by multivariate logistic analysis. The mathematical model for predicting the probability of a successful outcome was as follows: P = (1 + exp[0.144 × patient age − 0.059 × serum FSH concentration − 1.310 × JS])−1. When a predictive probability of 49.7% was selected as the best cut‐off value, sensitivity and specificity were 78.0% and 76.3%, respectively.

Conclusion:  This present model is very useful for predicting successful microdissection TESE. In addition, we suggest that a younger patient age would increase the probability of success with this procedure. (Reprod Med Biol 2005; 4: 53–57)
Role of tumor necrosis factor‐α in Gram‐negative bacterial lipopolysaccharides induced implantation failure
Authors: DEB KAUSHIK , CHATURVEDI MADAN MOHAN , JAISWAL YOGESH KUMAR
Published: March 2005

Background and aims:  Gram‐negative bacterial lipopolysaccharides (LPS) are known causative agents for pregnancy loss in mothers with genital tract infections. In this study, we attempt to test the role of tumor necrosis factor‐α (TNF‐α) in the normal physiological processes of preimplantation embryonic development and LPS induced pregnancy loss in mice. Since the preimplantation mouse embryos grow in an unattached state for a considerable period (day 1–4.5) of its development in the maternal environment, it is possible that a critical level of soluble and biologically active TNF‐α is maintained in the maternal environment, and that any alteration in this could lead to implantation failure. Here we determine the pattern and level of expression of TNF‐α gene in preimplantation stage embryos and uterus collected from control and LPS treated pregnant animals during different stages of preimplantation period of pregnancy by reverse transcriptase‐polymerase chain reaction.

Methods:  The concentrations and biological activity of soluble TNF‐α protein present in oviductal fluid (OF) and uterine fluid (UF), in the normal and LPS treated animals, were determined by enzyme‐linked immunosorbent assay and 3‐(4,5‐dimethylthiazol‐2‐yl) 2,5‐diphenyltetrazolium bromide assay on L929 cells, respectively. TNF‐α was also given i.p. to study its effect on implantation.

Results:  An early expression of TNF‐α messenger ribonucleic acid in the preimplantation stage embryos collected from LPS treated animals was observed along with a significant rise in the level of biologically active soluble TNF‐α in the OF. Similarly, the level of bioactive and soluble TNF‐α present in the UF from LPS treated animals was significantly higher as compared to the control on day 4.42 of pregnancy.

Conclusions:  TNF‐α given i.p. exerted similar effects on pregnancy as that of LPS. An incessant exposure of the preimplantation stage embryos to significantly high levels of maternal bioactive free/soluble TNF‐α, and an alteration in the normal pattern of its expression in the preimplantation stage embryos may be one of the causes of failure of implantation leading to poor pregnancy outcome in LPS treated mouse. (Reprod Med Biol 2005; 4: 79– 89)
A Practical Framework for the Analysis of Social Security Reform
Authors: DILNOT ANDREW , WEBB STEVEN
Published: March 2005

‘When I use a word’, Humpty Dumpty said in a rather scornful tone, ‘it means just what I choose it lo mean — neither more nor less’. (Through the Looking Glass, Ch. 6)
Horizontal Equity and the Taxation of Employed and Self‐Employed Workers
Authors: FREEDMAN JUDITH , CHAMBERLAIN EMMA
Published: March 2005

The schedular system of income tax in the UK frequently comes under attack, not least in relation to the distinctions it draws between the tax treatment of the employed and the self‐employed. However, on examination, it appears that non‐schedular systems of taxation share both these distinctions and the difficulties that arise from them, albeit to varying degrees. The division between employed and self‐employed is also problematic for social security systems. These difficulties are found, to a greater or lesser extent, in all the jurisdictions studied by the authors. It may be argued that all or some of the tax and social security differences are justified by fundamental economic and legal differences between the nature of employment and self‐employment relationships. This may be true where the relationships compared are unambiguously, on the one hand, employment and, on the other, self‐employment. However, there have always been non‐standard relationships that combine characteristics of both these broad categories. This grey area appears to be increasing with changing work patterns. Consequently, the simple dichotomous system adopted by the UK tax and social security systems has come under pressure. This article considers the problems arising from this situation and some of the ideas that have been put forward to deal with them.

JEL classification: H24, K34.
Trends in Charitable Giving
Authors: PHAROAH CATHY , TANNER SARAH
Published: March 2005

The charitable giving of UK households has changed considerably over the past 20 years. In particular, the proportion of households giving to charity fell by 5 percentage points between 1974 and 1993–94. An increase in the average size of donations meant that total voluntary income increased in real terms over the period, but, since 1988, voluntary income has stagnated. The greatest falls in the number of givers are among households in their twenties and thirties. There are clear trends in giving across households by age and income, with younger and poorer households tending to give less. But not only are today's younger households less likely to give than today's middle‐aged households; they are also less likely to give than today's middle‐aged households did when they were young. These generational trends in giving do not bode well for levels of voluntary income in the future.

JEL classification: D12. D16.
Expression of p63 and p73 in ameloblastomas
Authors: Kumamoto Hiroyuki , Ohki Kousuke , Ooya Kiyoshi
Published: March 2005

Background:  To clarify the role of p53 homologs in oncogenesis and cytodifferentiation of odontogenic tumors, expression of p63 and p73 was analyzed in ameloblastomas as well as tooth germs.

Methods:  Tissue specimens of nine tooth germs and 48 benign and five malignant ameloblastomas were examined by immunohistochemistry and reverse transcriptase‐polymerase chain reaction (RT‐PCR) for the expression of p63 and p73.

Results:  Immunoreactivity for p63 and p73 was evident in epithelial cells neighboring the basement membrane in developing and neoplastic odontogenic tissues. p63 expression in desmoplastic ameloblastomas was significantly higher than in acanthomatous and granular cell ameloblastomas, and ameloblastic carcinomas showed higher p63 expression than metastasizing ameloblastomas. p73 expression was significantly higher in plexiform ameloblastomas than in follicular ameloblastomas, and basal cell ameloblastomas showed higher p73 expression than granular cell ameloblastomas. mRNA transcripts for ΔNp63 and TAp73 were detected in all developing and neoplastic odontogenic tissues. TAp63 mRNA was expressed in five of eight tooth germs, 16 of 34 ameloblastomas, and one of one malignant ameloblastoma, whereas ΔNp73 mRNA was recognized in one of eight tooth germs, nine of 34 ameloblastomas, and one of one malignant ameloblastoma.

Conclusion:  The expression of p63 and p73 suggests that these p53 homologs play a role in differentiation and proliferation of odontogenic epithelial cells. Variations of predominantly expressed isoforms suggest that p63 and p73 might differentially function in odontogenic tissues.
Ultraviolet‐free phototherapy
Authors: Krutmann Jean , Medve‐Koenigs Kathrin , Ruzicka Thomas , Ranft Ulrich , Wilkens Jan H.
Published: March 2005

Background: Ultraviolet (UV) radiation phototherapy has been used for decades in the management of common skin diseases. On the other hand, UV radiation is a complete carcinogen and as a consequence, UV phototherapy is usually not used for the long‐term management of children and young adults and in combination with topical or systemic immunosuppressants.

Purpose: The therapeutic effectiveness of a new UV‐free irradiation device in the treatment of patients with atopic hand and/or foot eczema was studied.

Methods: In a single‐blinded trial 10 patients with atopic hand and/or foot eczema were treated with a sham irradiation device and with the new developed UV‐free irradiation device DermoDyne® during the following 4 weeks. All irradiation's lasted 30 min per treatment three times weekly.

Results: UV‐free irradiation was found to induce a significant clinical improvement of atopic hand and foot eczema (P=0.0001) in marked contrast to the sham‐irradiation (P=0.39).

Conclusion: Our studies demonstrate that visible light can be successfully used for the treatment of patients with atopic eczema.
UVA1 phototherapy for disseminated granuloma annulare
Authors: Schnopp C. , Tzaneva S. , Mempel M. , Schulmeister K. , Abeck D. , Tanew A.
Published: March 2005

Background/Purpose: Disseminated granuloma annulare is a benign granulomatous skin disease of unknown etiology. Recently, UVA1 (340–400 nm) phototherapy has been found effective in a small series of four patients. The purpose of this two‐center study was to determine the rate and duration of clinical response to UVA1 phototherapy in a larger cohort of 20 patients with disseminated granuloma annulare.

Methods: Twenty patients with long‐standing, stable disease (median 42 months, 95% CI 23–105) underwent UVA1 phototherapy. Sixteen patients were treated with a high‐dose regimen (median single dose 110 J/cm2, 95% CI 103–121) and four patients with a medium‐dose regimen (median single dose 50 J/cm2, CI 50–50). The clinical response was graded on a 5‐point scale [0=none, 1=poor, 2=moderate, 3=substantial, 4=(near) complete]. After cessation of therapy, patients with a clinical score of 3 or 4 were followed up to evaluate the duration of clinical improvement.

Results: At the end of treatment, five patients each had substantial improvement or (near) complete clearance. Another five patients had a moderate response, three patients were considered as poor responders and two patients as treatment failures. Out of the 10 patients with good or excellent response nine were available for follow up. Of these, two patients were still clear after 3 and 6 months, and seven patients relapsed after a median of 3 months (95% CI 1.68–6.46).

Conclusions: UVA1 phototherapy provided good or excellent results in half of our 20 patients with disseminated granuloma annulare. In the majority of patients with a satisfactory response, however, discontinuation of treatment was followed by early recurrence of disease.
New Faces of the Familiar Clathrin Lattice
Authors: Wilbur Jeremy D. , Hwang Peter K. , Brodsky Frances M.
Published: March 2005

The clathrin triskelion self‐assembles into a lattice that coats transport vesicles participating in several key membrane traffic pathways. A new model of a clathrin lattice at approximately 8 Å resolution, generated by Fotin et al. (Nature 2004;432:573) confirmed the basic structural features of clathrin that were defined over many years of biochemical and structural analysis. In addition, new structural features of the clathrin trimerization domain were modelled for the first time, and the predictions correlated well with previous biochemical studies. A second model, placing auxilin within the lattice suggested a possible lattice contact targeted during lattice disassembly (Fotin et al. Nature 2004;432:649). This contact predicts interactions of the newly modelled trimerization domain with a newly defined extension of the clathrin triskelion, the ankle domain. These aspects of the new models were emphasized in the published reports describing them and in recent commentary (Brodsky, Nature 2004;432:568). Also emerging from the new models is a better picture of how the clathrin structure is distributed throughout the lattice, allowing the first predictions of interacting molecular interfaces contributing to contacts in the assembled lattice. The focus of this interchange is to emphasize these additional features revealed by the recently published models from Fotin and colleagues.
Probing the magnetoacoustic boundary layer in the peculiar magnetic star 33 Lib (HD 137949)
Authors: Kurtz D. W. , Elkin V. G. , Mathys G.
Published: March 2005

We show unprecedented resolution of the amplitudes and phases of the principal 2.015-mHz mode and its 4.030-mHz harmonic as a function of atmospheric depth in the roAp star 33 Lib using high-resolution Very Large Telescope (VLT) Ultraviolet–Visual Echelle Spectrograph (UVES) spectra. We show that the pulsation amplitude increases upwards into the Nd iii line-forming layer away from an atmospheric node, and increases downwards from the same node in the Nd ii line-forming layer. We suggest that the Nd iii layer, which arises at, or above, τ ∼ 10−3, overlaps with the magnetoacoustic boundary layer, and that our detailed observations of pulsation amplitude and phase variations with depth provide a first probe of this layer.
Evaluation of Leak-Before-Break (LBB) Behavior For Axially Notched X65 and X80 Line Pipes
Authors: Kawaguchi Shinobu , Hagiwara Naoto , Masuda Tomoki , Toyoda Masao
Published: March 2005

Leak-before-break (LBB) behavior was evaluated for two series of API 5L X65 line pipes and three series of X80 line pipes with various levels of Charpy V-notch (CVN) absorbed energy. Full-scale hydrostatic burst tests were conducted for the line pipes with an axial through-wall (TW) notch to determine LBB criteria, that is, the relationship between the axial TW notch length and hoop stress for LBB. The determined LBB criteria were verified by full-scale partial gas burst tests for line pipes with an axial part-through-wall (PTW) notch and were then compared to the estimation using the CVN energy-based equation that Kiefner et al. have proposed. The present study demonstrated that the estimation using the CVN-based equation was in good agreement with the experimental results for the pipes with a relatively low CVN energy of less than 130 J. On the contrary, the equation was not applicable to the pipes with a relatively high CVN energy of more than 130 J. The results of instrumented Charpy tests clarified that the load versus load-point displacement curves for Charpy specimens from the high CVN energy pipes were different from those from the low CVN energy pipes. Therefore, the applicability of the CVN-based equation was dependent on the load versus load-point displacement curve for a Charpy specimen.
Response Spectrum Estimation for Fixed Offshore Structures With Inundation Effect Included: A Price’s Theorem Approach
Authors: Zheng Xiang Yuan , Liaw Chih Young
Published: March 2005

Instead of a Volterra-series based method, a method based on Price’s theorem and Fourier Transforms is proposed for evaluating the nonlinear response power spectra of fixed offshore structures modeled as finite-memory systems. The numerical computation effort required for spectral estimations using the proposed method is significantly less than that of the Volterra-series method that requires multi-dimensional integrations. Nonlinear frequency-domain analyses of two jack-up platform structures are carried out to study the effects of inundation, cubic and quartic drag terms and polynomialization methods.
Etching mechanisms of Si and SiO2 in inductively coupled fluorocarbon plasmas: Correlation between plasma species and surface etching
Authors: Gaboriau F. , Fernandez-Peignon M-C. , Cartry G. , Cardinaud Ch.
Published: March 2005

Etching mechanisms of silicon and silicon oxide in a fluorocarbon environment are studied in an ICP reactor. Optimization of the process for deep etching of SiO2 with a Si mask has been discussed in a previous article. In this article, adequate plasma conditions are chosen both (a) to allow separation of parametric variables and (b) to get appreciable variation of the different plasma and surface experimental results versus parameters. Hence, pressure, source power, ion energy, and subsequently ion flux are kept constant. The influences of the gas composition and the residence time (varying gas flow rate) are studied. We show that silicon etching depends both on the atomic fluorine concentration in the plasma and of the fluorocarbon blocking layer at the surface. We pay particular attention to the formation of the fluorocarbon overlayer. We establish that the thickness of this layer is linked to the plasma species through the (C+H)∕F ratio, calculated from the radical densities in the gas, taking into account the etching-deposition competition. Concerning oxide etching in the so-called sputtering regime, we show that the overlayer detected by x-ray photoelectron spectroscopy does not control the etching mechanism and seems to be an interaction layer between plasma and oxide rather than a blocking layer. We also establish a linear relation between oxide etch yield and the average F∕C ratio calculated from the ion densities indicating that the radical species are not a limiting factor in the oxide etching mechanism. Finally, from these results for oxide and silicon etching, a correlation between plasma species and the evolution of the etch rates versus ion energy is done by varying gas composition and residence time.
Ion-assisted physical vapor deposition for enhanced film properties on nonflat surfaces
Authors: Alami J. , Persson P. O. Å. , Music D. , Gudmundsson J. T. , Bohlmark J. , Helmersson U.
Published: March 2005

We have synthesized Ta thin films on Si substrates placed along a wall of a 2-cm-deep and 1-cm-wide trench, using both a mostly neutral Ta flux by conventional dc magnetron sputtering (dcMS) and a mostly ionized Ta flux by high-power pulsed magnetron sputtering (HPPMS). Structure of the grown films was evaluated by scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The Ta thin film grown by HPPMS has a smooth surface and a dense crystalline structure with grains oriented perpendicular to the substrate surface, whereas the film grown by dcMS exhibits a rough surface, pores between the grains, and an inclined columnar structure. The improved homogeneity achieved by HPPMS is a direct consequence of the high ion fraction of sputtered species.
Improved crystal grinding and polishing holder for metal single crystal preparation
Authors: Maksymovych Petro , Gasmire Thomas , Ohno Shinya , Yates John T.
Published: March 2005

An automatic fixture for polishing a single crystal on a mechanical polishing machine has been designed and tested on a soft metal, aluminum. Crystal radii of the order of 3 m may be achieved without personal attention to the polishing work, minimizing the atomic step density due to crystal curvature.
An innovation in physics instruction for nonscience majors
Authors: Moore J. A.
Published: March 2005

A device, the M-R diagram, is described which makes possible an easily comprehended overview of the structures in the universe and simultaneously permits an appreciation of the various domains dictated by the requirements of the laws of physics.
Radius of curvature of the cornea—an experiment for the life-science physics lab
Authors: MacLatchy C. S.
Published: March 2005

A quantitative experiment in geometrical optics for the life-science physics laboratory is presented. It involves the student in the measurement of the radius of curvature of the cornea and is based on an old method devised by Kolrausch in 1839.
Multiple level lecture series—an alternative to the normal lower division physics sequence
Authors: Fisher Richard L.
Published: March 2005

The multiple level lecture series was developed to meet the physics requirements of students in a small community college. The physics requirements have increased in the last few years with the University of California introducing an introductory calculus level physics. With normally small enrollments in all courses, it has become increasingly difficult to support any course. The multiple level lecture series offers one lecture series over all topics of physics each semester. The lecture series consists of a series of topics with each lecture in the topic becoming more mathematically sophisticated. Students attend only those lectures up to their mathematical ability. The lecture series has been a success in meeting all demands placed on it, and part or all of the results can be applied to any physics curriculum.
Two further experiments on electron interference
Authors: Matteucci G. , Pozzi G.
Published: March 2005

Two experiments concerning the phenomena of the interference of probabilities and of the so-called Aharonov-Bohm effect have been realized using an electron biprism as interferometric device and a standard electron microscope as electron optical bench. The obtained results are presented.
Random walks and diffusion
Authors: Domb Cyril , Offenbacher Elmer L.
Published: March 2005

The usual solution of the diffusion equation gives inaccurate results for short diffusion times for displacements which are relatively large compared to the maximum range of the diffusion. A method is proposed for solving the diffusion equation by a random-walk approximation technique which utilizes the appropriate generating functions and the complex integration method of steepest descent. The power of the method is illustrated for a one-dimensional random walk (SRW) and for physical situations in which the elementary diffusion process is governed by a normal or a rectangular probability distribution. Formulas for higher approximations applicable to any probability distribution are also derived. The method, which can also be applied to two and three dimensions, is capable of yielding high accuracy for the diffusion solution over the entire diffusion domain.
Logarithms!
Authors: Mermin N. David
Published: March 2005

The joy that physicists derive from numbers, an introduction to the art of estimating, and a healthy ambivalence toward pocket calculators, can all be revealed to students in a ’’liberal arts physics’’ course, by a novel way of reviewing the properties of exponents.
The nature of things—a one-semester survey for nonscientists
Authors: Coker W. R.
Published: March 2005

An attempt to survey all of the topics traditionally covered in undergraduate physics courses in one semester, with strong emphasis on everyday phenomena of nature, is described. In order to compress a survey course in physics into one semester, a number of unusual techniques were used and are described. A point was also made, during the course, to debunk certain brands of pseudoscience popular among college students, with mixed success. The course was aimed at the mass audience of nonscience majors having only a one-semester general sciences degree requirement, used no details of mathematics, and relied heavily on lecture demonstrations, slides, film-loops, and overhead projector artwork.
One-piece Faraday generator: A paradoxical experiment from 1851
Authors: Crooks M. J. , Litvin D. B. , Matthews P. W. , Macaulay R. , Shaw J.
Published: March 2005

In the conventional Faraday generator a conducting disk rotates in an axial magnetic field. If the disk is replaced by a cylindrical permanent magnet that supplies its own magnetic field, the effect is identical. It follows that any moving magnet generates an induced electromotive force due to the presence of its own field: this generalization leads to an apparent paradox in the case of translational motion for it implies the possibility that an observer in an inertial frame could measure his absolute velocity.
Debye potential representation of vector fields
Authors: Gray C. G. , Nickel B. G.
Published: March 2005

A simple proof is given of the theorem that an arbitrary divergenceless vector field F can be represented in terms of two scalar fields (Debye potentials) ψ and χ according to F=Lψ+∇×Lχ, where L is the angular momentum operator. The questions of uniqueness and completeness of this representation are discussed, and the importance of the theorem in electromagnetic theory is emphasized.
An experiment to demonstrate the energy broadening of annihilation gamma rays
Authors: Ouseph P. J. , DuBard James L.
Published: March 2005

When positrons annihilate in solid materials the energy distribution of the annihilation gamma rays, measured in terms of the full width at half maximum of the gamma-ray peak, is much broader than that of a 0.511-MeV gamma peak. This broadening is caused by the momentum distribution of the electrons in the material. Details of the experiment are given in the article.
On the complementary Lagrange formalism of classical mechanics
Authors: Stickforth J.
Published: March 2005

Corben and Stehle pointed out the possibility of a Lagrange formalism in classical momentum space. In the present paper a more detailed discussion of this formalism is given, stressing two facts: (1) Contrary to Corben and Stehle’s opinion this formalism might be of real practical importance. (2) This formalism makes it evident that dissipation is still a problem in classical mechanics.
Generalized heat conduction equation
Authors: Swenson Robert J.
Published: March 2005

The linear constitutive relation between heat flux and temperature gradient known as Fourier’s law is modified to be nonlocal in time; i.e., the heat flux depends on the past history of the temperature gradient. It is shown that this leads to a generalized heat conduction equation which can be hyperbolic and thus possess a wavelike solution with finite velocity of propagation of a heat pulse. In two extreme limits of very short and very long memory the equation reduces, respectively, to the usual parabolic heat conduction equation and to a hyperbolic wave equation. For in between memory the equation has the properties of a telegraph equation characterized by a relaxation time. Such equations have arisen in treatments of second sound, exciton transport, and quasiparticle transport in 3He.
Classes of units in the SI
Authors: Page Chester H.
Published: March 2005

The mathematical nature of the categories of base, supplementary, and derived units in the SI is explained, and the usual definition of ’’supplementary’’ modified to be more precise. An argument is presented for adding ’’neper’’ to the SI as a supplementary unit.
Light transmission through reflecting cylindrical tubes
Authors: Cohen D. K. , Potts J. E.
Published: March 2005

When viewed through a cylindrical tube with highly reflecting inner walls, a point source of light appears as a series of sharply defined rings. This easily observed effect is shown to arise from multiple reflections of the light from the inner walls. The ring pattern can easily be projected onto a screen for a classroom demonstration and to permit quantitative measurements of the ring parameters.
The Coulomb problem and the Maxwell fish-eye problem
Authors: Chen Augustine C.
Published: March 2005

The potential related to the Maxwell fish-eye problem by optico-mechanical analogy is derived from mechanical considerations. The dynamics of this potential is shown to be related to the dynamics of the Coulomb potential by an exchange transformation. The effective potential obtained from the transformation for the Coulomb problem in momentum space is used to discuss the anomalous behavior of the Coulomb trajectories in momentum space. Derivations of the index of refraction in the original Maxwell problem as well as its generalization are given.
Heat engines and the performance of external work
Authors: Leff Harvey S.
Published: March 2005

A simple model is proposed whereby the work per cycle done on an external agent by a reversible heat engine can be analyzed explicitly. The external agent is a sand reservoir with a specified initial vertical weight distribution. During each successive cycle of the engine, this distribution becomes more nonuniform, with sand being shifted from lower to higher levels. The increase in the sand’s gravitational potential energy is equal to the corresponding work done by the engine. Several different cycles are discussed and the change per cycle in the sand’s weight distribution is calculated and graphed for each. The model and its major results are suitable for presentation to a wide audience of physics students.
Hyperbolic motion and radiation
Authors: Cohn Jack
Published: March 2005

The problem of the radiation emitted by a charged particle undergoing (eternal) hyperbolic motion is considered. The early approach of Pauli whereby such a system does not radiate and the formulations of more recent authors under which the system does radiate are presented within a unified framework. From this perspective it becomes clear why Pauli’s approach is not valid for this unusual problem. The discussion hinges upon the demonstration of the Lorentz invariant result that, for eternal hyperbolic motion, the radiant energy flux is not given by the flux of the total Poynting vector, before the charge reaches the turning point.
Transformation properties of electric and magnetic fields
Authors: Cohn Jack
Published: March 2005

The transformation properties of electric and magnetic fields as a consequence of the Lorentz or conformal covariance of Maxwell’s equations is considered. The customary transformation rules for E and B are shown to actually not be necessary consequences of, but only sufficient conditions for the above covariance. Conditions are then derived under which the customary transformation rules for E and B do follow from the covariance of Maxwell’s equations. The conditions needed for the Lorentz and conformal transformations are different, but apparently are compatible.
Mutual inertia
Authors: Ouellette P. E.
Published: March 2005

The mutual inertia concept is introduced through the study of the small oscillations of a periodic linear chain of particles gliding on an air-track and joined by loaded strings. The term ’’mutual inertia’’ is clarified by considering the electrical analog of the chain. In this LC ladder network the neighboring inductors are coupled through mutual inductance, which is the electrical counterpart of ’’mutual inertia.’’ A pure asymmetrical mutual inertia coupling is then dealt with in order to provide a more encompassing description of the concept. Finally, the limit case of a perfect transformer is considered.
Double-group theory on the half-shell and the two-level system. I. Rotation and half-integral spin states
Authors: Harter William G. , dos Santos Narciso
Published: March 2005

A geometrical construction by Hamilton is used to simplify the quantum mechanics of half-integral spin. A slide rule is described which can be used to (a) compute products of half-integral or integral spin rotation operators, (b) convert between the Euler-angle and ’’axis-angle’’ rotation operator parameters, and (c) calculate the time evolution of a spin-1/2 state for a constant Hamiltonian operator. A type of nomogram is developed which suggests ways to simplify the ’’double-group’’ theory of half-integral spin in molecular point symmetry, as well as the ’’ordinary’’ group theory for integral spin systems. Cubic and icosahedral symmetry group characters are derived for half-integral spin operators.
Gauge invariance rediscovered
Authors: Moriyasu K.
Published: March 2005

A pedagogical approach to gauge invariance is presented which is based on the analogy between gauge transformations and relativity. By using the concept of an internal space, purely geometrical arguments are used to teach the physical ideas behind gauge invariance. Many of the results are applicable to general gauge theories.
Magnetostatic multipoles in Cartesian coordinates
Authors: Castellanos A. , Panizo M. , Rivas J.
Published: March 2005

A general expression for the magnetostatic multipole of order n in Cartesian coordinates is presented.
Recurrence effects in the parametric spring pendulum
Authors: Falk Lars
Published: March 2005

The parametric spring-pendulum shows recurrence effects which are given a simple perturbation analysis. The recurrence depends on the existence of two conservation laws which determine the motion in an intermediate region; oscillations outside this region are unstable and must return. The relation to the Fermi-Pasta-Ulam problem is given together with the explicit solution.
Longitudinal impact of rods: A continuing experiment
Authors: Britton W. G. B. , Fendley J. J. , Michael M. E.
Published: March 2005

An electronic timer has been used in a first-year experiment to measure the time of contact of metal rods bouncing on a steel plate. The method, which is reliable and quick, allows a student to take a sufficient number of results during a three-hour laboratory session to investigate the relationship between time of contact and such variables as impact velocity, length, elastic modulus, and density of the rod. An investigation of the dependence of contact time on length showed the limitations of the elementary (St.Venant) theory and led to the project reported here. Some aspects of the work, including the use of strain gauges, form a natural extension of the first-year experiment: other features of the impact process could be further investigated in an undergraduate project.
A simple experiment to demonstrate Coulomb’s law
Authors: Wiley P. H. , Stutzman W. L.
Published: March 2005

A simple classroom demonstration for verifying the inverse square law nature of Coulomb’s law is described. It involves simple equipment and can be performed in a few minutes. The experiment proceeds by equally charging two pitch balls on long strings, discharging one pith ball, and measuring the relative separation in each case. No charge, mass, or force measurements are necessary. An accuracy of about 2% is typical for this experiment.
A heuristic potential theory of electric and magnetic monopoles without strings
Authors: Barker William A. , Graziani Frank
Published: March 2005

A simple spherical distribution of electric and/or magnetic charge moves with a constant velocity with respect to an observer in the laboratory frame. The electric and magnetic potentials are written in the rest frame of the two types of charge, and in the laboratory frame by means of the Lorentz transformation. The E and H fields are evaluated and are shown to be consistent with Maxwell’s equations, generalized to include magnetic charge. In this development a ’’scalar’’ rather than a ’’vector’’ potential is used to describe the magnetic monopole at rest, thus avoiding ’’string theory.’’ This approach leads to a more complicated, but still useful form for the classical Lagrangian.
Relativistics statics and F. W. Sears
Authors: Gro/n O/.
Published: March 2005

In a preliminary manuscript, written May 1975, F. W. Sears has argued that the paradox of the right angle lever arises from the use of the noncovariant definition of length, with which the Lorentz contraction is connected. He suggested that the problems connected with relativistic formulations of statics would be removed by a manifestly covariant description, using tensor quantities only. In this article a covariant formulation of the torque/angular mementum relationship is discussed, and it is shown that this covariant formulation requires an asynchronous description in an arbitrary inertial frame.
Galileo and the Tower of Pisa experiment
Authors: Adler Carl G. , Coulter Byron L.
Published: March 2005

A study of Galileo’s book On Motion shows that many modern textbooks misrepresent what he would have been trying to prove in the legendary Tower of Pisa experiment. Recently performed experiments and calculations based on the current theory of falling bodies also show that it is doubtful if Galileo could have obtained the results claimed in the legend.
Circumventing Newton: A study in scientific creativity
Authors: Gingerich Owen
Published: March 2005

Is there a parallel between the creative work of Newton and of Beethoven? This question provides the background for a specific case study in a natural sciences course for nonscience students. The case study shows how Kepler’s three laws can be derived either from the standard Newtonian concepts, or alternatively from conservation laws. The latter approach does not use concepts of force or inertial straight-line motion. By demonstrating an alternative physical framework to explain certain basic celestial phenomena, Newton’s accomplishment becomes more personally his own. There is no necessity in nature that the Newtonian world system had to be found. Newton’s Principia is a personal achievement that places him in the same creative class as Beethoven or Shakespeare.