bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of memorization in physics education
Authors: Whitaker M. A. B.
Published: March 2005

A published statement that the physics student needs to memorize values of physical constants is questioned. It is pointed out that understanding, not memorization, should be aimed at. Requirement for the latter should be minimized, though it is reasonable to demand order-of-magnitude knowledge of important constants which have direct experimental significance. Values of constants are categorized as a crude kind of ‘‘craftsman’s knowledge’’ which may be obtained genuinely only from experience, not by learning.
Spacecraft navigation and relativity
Authors: Flynn Robert W.
Published: March 2005

Special relativity relates measurements in a ‘‘moving’’ frame to measurements in a ‘‘rest’’ frame. Navigation, as it is performed in practice, uses neither pure a ‘‘rest’’ nor pure a ‘‘moving’’ frame, but instead measures distance in the fixed, Earth, frame and time in the moving, ship, frame. Brehme diagrams arise naturally when relative motion is considered using navigational coordinates. In navigational coordinates the Lorentz transformation is expressible as an ordinary orthogonal transformation.
Electric resistive space heating
Authors: Bodansky David
Published: March 2005

The cost of heating residential buildings using electricity is compared to the cost employing gas or oil. (AIP)
Particle simulation of plasmas and stellar systems
Authors: Tajima T. , Clark A. , Craddock G. G. , Gilden D. L. , Leung W. K. , Li Y. M. , Robertson J. A. , Saltzman B. J.
Published: March 2005

A computational technique is introduced which allows the student and researcher an opportunity to observe the physical behavior of a class of many-body systems. A series of examples is offered which illustrates the diversity of problems that may be studied using particle simulation. These simulations were in fact assigned as homework in a course on computational physics.
Demonstration of wave propagation in a periodic structure
Authors: Cross Rodney C.
Published: March 2005

Simple apparatus is described which demonstrates wave propagation in an infinitely long periodic structure. The structure consists of a toroidal transmission line with periodic variation of the wave phase velocity around the line. Results are presented to illustrate the effect of the periodic perturbation on the resonant frequencies of the system.
de Mora Luminis: A spectacle in two acts with a prologue and an epilogue
Authors: Wróblewski Andrzej
Published: March 2005

Roemer’s work on the velocity of light has been incorrectly described in many physics texts and books dealing with the history of science. The evolution of the misinformation is discussed and documented in this paper, which uses this example to call attention to how negligently many authors of physics texts deal with the history of physics.
Teaching a microcomputer a bit of algebra
Authors: Snider Dale R. , Hock Jeffrey L.
Published: March 2005

A basic computer program is described which can be used to evaluate the determinant of an N×N matrix whose elements are symbolic. The elements of the matrix can be multiterm polynomials of a few (<10) variables. A discussion of how the program works, how to use the program, and how the program can be used for other algebraic applications is provided.
Strong interaction and nucleon mass
Authors: Massa Corrado
Published: March 2005

Scalar field equations are developed on the assumption that a nucleons mass is stored in its surrounding Yukawa field. (AIP)
Analog of Birkhoff’s theorem for classical Yang–Mills theories
Authors: Pappas Richard C.
Published: March 2005

Through the use of Lie algebra, it is shown that a spherically symmetric solution of the field equations in Yang−Mills theory must be static. (AIP)
Correlations in separated quantum systems: A consistent history analysis of the EPR problem
Authors: Griffiths Robert B.
Published: March 2005

The familiar problem of two separated, noninteracting spin- 1/2 particles in a state of zero total spin is analyzed using the consistent history interpretation of quantum mechanics and shown to behave in many respects like a classical system of two noninteracting objects whose individual properties are unknown but strongly correlated with each other. There is no action at a distance between the particles and a measurement on one has no effect whatsoever on the other. However, the result of a measurement of a spin component of one of the particles can be used to infer (correctly) its value prior to the measurement, and also the corresponding spin component of the other particle at all times prior to when that particle interacts with something else. In these respects the quantum system behaves like its classical counterpart. On the other hand, the paradoxical (nonclassical) aspects of the quantum situation seem to be precisely those already present in the quantum theory of a single particle.
Ehrenfest theorem and the classical trajectory of quantum motion
Authors: Nag J. , Menon V. J. , Mukherjee S. N.
Published: March 2005

Ehrenfest theorem asserts that the quantum mechanical motion of a particle when considered in the expectation value sense should agree with classical mechanics in the correspondence limit. An explicit verification of this result is presented in the one-dimensional case for motion in an infinite potential well (large quantum number limit) and a brief mention is made of the case of a smooth potential (ℏ→0 limit).
Optical diffraction pattern measurements using a self-scanning photodiode array interfaced to a microcomputer
Authors: Wesley James T. , Behof Anthony F.
Published: March 2005

A system for recording and analyzing optical diffraction patterns using a self-scanning photodiode array interfaced to a popular microcomputer is described. The detector array consists of 128 photodiodes on 25-μm centers and is sensitive to light in the visible portion of the spectrum. Details of the interface between the array and an Apple II microcomputer are given. The overall performance of the system is demonstrated for Fresnel diffraction by a single slit.
The rolling unrestrained brachistochrone
Authors: Yang Ju-xing , Stork David G. , Galloway David
Published: March 2005

We have generalized the unrestained brachistochrone problem to include rolling objects in order to construct a demonstration brachistochrone track. Due to the nature of the constraints this well-posed extremal problem cannot be solved using the techniques of Euler and Lagrange. The solution, parametrized by a measure of the generalized cylinder’s moment of inertia, reduces to that for the (sliding) unrestrained brachistochrone in the limit of vanishing moment of inertia.
Unified vector derivation of Gantmakher’s, rotation, and charged particle deflection formulas
Authors: Aravind P. K.
Published: March 2005

Gantmakher’s formula for the Coriolis deflection of a point mass moving in a uniform gravitational field is derived by vector methods. The results for the eastward deflection of a falling object and the lateral deviation of a horizontally fired projectile are derived as special cases of this formula. A homogeneous variant of Gantmakher’s formula is shown to yield the rotation formula describing the change in a vector rotated through a finite angle about a fixed axis. The motion of a point charge in constant uniform electric and magnetic fields is also shown to be solved by Gantmakher’s formula.
An expectation value formulation of the perturbed Kepler problem
Authors: Curtis Lorenzo J. , Haar Roger R. , Kummer Martin
Published: March 2005

A classical formulation of the nonrelativistic Kepler problem in terms of expectation values of powers of the radial coordinate r is presented. Perturbations to this problem arising from relativistic corrections to the kinetic and potential energies, multipole moments of the central potential, other confocal orbitals, etc. can be written in terms of powers of r and thus be accounted for through these expectation values in a simple and pedagogically transparent way. Macroscopic and microscopic examples are treated as special cases of this common formulation.
Diffraction patterns for the oblique incidence gratings
Authors: Phadke Laxman G. , Allen Jim
Published: March 2005

A coarse grating and a narrow laser beam demonstrate a pattern of diffraction beads perpendicular to both the direction of rulings and the direction of the incident light. As the angle of incidence is changed, with the rulings still perpendicular to the incident light, the beads in the pattern separate along the same straight line. In contrast, we describe what is observed when the grating is rotated perpendicular to the above. The bead pattern now forms the arc of a circle. We derive the expressions for the patterns and present photographic illustrations.
Frequency-dependent performance of a nonideal Carnot engine
Authors: Rebhan E. , Ahlborn B.
Published: March 2005

The average power output P, efficiency η′, and entropy production Ps have been determined as function of cycle frequency ν for a nonideal Carnot engine where the ratio r of the heat absorption time and heat rejection time can be varied and the heat is transferred by conduction into the working fluid. The power output has an optimum at the value r=(β/α)1/2, where α and β are the thermal conductances of the upper and lower isotherm, respectively. The efficiency decreases and the conduction losses increase drastically with cycle frequency. The power output goes through a maximum, peaked at a frequency ν*. The efficiency can be increased without much sacrifice in power output if the engine is run below the frequency ν* (12% efficiency increase at 3% loss in power for ν=0.85ν*). The entropy production grows approximately as Ps ∼ν2.
Approximations for the range of ballistic missiles
Authors: Snyder Ralph
Published: March 2005

The actual range, flight time, and maximum height of an ICBM are compared to the predictions of five simple approximations that are more sophisticated than the standard flat-Earth-with-constant-gravity problem but more elementary than the full Keplerian solution. The simplest of these approximations is accessible to first-year students and gives results in closed form whose range predictions are in good agreement with the Keplerian ranges at typical ICBM speeds.
Fluid flow and particle trajectories around simple bodies: Impaction of snowflakes on car windshields
Authors: King W. D. , Dujmovic S.
Published: March 2005

The airflow around a simple automobile shape is calculated using a distributed source–sink technique. This is then used to determine the trajectories of snowflakes, and it is shown that, for a given snowflake size, there is a range of travel speeds that minimizes the impaction of snowflakes on the windshield.
Considerations on the precessing orbit via a rotating Laplace–Runge–Lenz vector
Authors: Yoshida T.
Published: March 2005

For the relativistic Kepler–Coulomb problem, a rotating Laplace–Runge–Lenz vector is constructed as an extension of the well-known conserved vector for the Kepler–Coulomb problem. Motion of the turning point in the precessing orbit is analyzed from the considerations on the coordinate systems related to the rotating vector.
Trajectories of projectiles in air for small times of flight
Authors: Kemp H. R.
Published: March 2005

Angle of departure, angle of fall, and the position of the summit of trajectories in air are calculated with neglect of the effect of the air on the fall from the line of departure. Experimental information required is times of flight against range or remaining velocities against range. Calculated values are compared with observed values for a supersonic bullet.
Microwave measurements of a fluorescent lamp plasma
Authors: Ffield Amy , Wolfson Richard
Published: March 2005

We describe an undergraduate plasma physics experiment using an easily constructed and inexpensive apparatus that nevertheless involves the more advanced physics of the interaction between plasma and electromagnetic radiation. The experiment is based on the readily available plasma of a fluorescent lamp. The lamp is placed inside a resonant cavity and the shifts in the frequencies of cavity resonances are used to determine the plasma density as a function of time. We describe a circuit that allows measurements to be made of the decay of the afterglow plasma, and show experimentally determined decay rates and densities that are consistent with the literature on fluorescent lamps and gas discharges.
Functional Analysis of All Nonribosomal Peptide Synthetases in
Cochliobolus heterostrophus
Reveals a Factor, NPS6, Involved in Virulence and Resistance to Oxidative Stress
Authors: Lee Bee-Na , Kroken Scott , Chou David Y. T. , Robbertse Barbara , Yoder O. C. , Turgeon B. Gillian
Published: March 2005

Nonribosomal peptides, made by nonribosomal peptide synthetases, have diverse biological activities, including roles as fungal virulence effectors. Inspection of the genome of
Cochliobolus heterostrophus
, a fungal pathogen of maize and a member of a genus noted for secondary metabolite production, revealed eight multimodular nonribosomal peptide synthase (
NPS
) genes and three monomodular
NPS
-like genes, one of which encodes a nonribosomal peptide synthetase/polyketide synthase hybrid enzyme presumed to be involved in synthesis of a peptide/polyketide molecule. Deletion of each
NPS
gene and phenotypic analyses showed that the product of only one of these genes,
NPS6
, is required for normal virulence on maize. NPS6 is also required for resistance to hydrogen peroxide, suggesting it may protect the fungus from oxidative stress. This and all other
nps
mutants had normal growth, mating ability, and appressoria. Real-time PCR analysis showed that expression of all
NPS
genes is low (relative to that of actin), that all (except possibly
NPS2
) are expressed during vegetative growth, and that expression is induced by nitrogen starvation. Only
NPS6
is unfailingly conserved among euascomycete fungi, including plant and human pathogens and saprobes, suggesting the possibility that NPS6 activity provides oxidative stress protection during both saprobic and parasitic growth.
Mutator
-Like Element in the Yeast
Yarrowia lipolytica
Displays Multiple Alternative Splicings
Authors: Neuvéglise Cécile , Chalvet Fabienne , Wincker Patrick , Gaillardin Claude , Casaregola Serge
Published: March 2005

A new type of DNA transposon,
Mutyl
, has been identified in the sequenced genome of the yeast
Yarrowia lipolytica
. This transposon is 7,413 bp long and carries two open reading frames (ORFs) which potentially encode proteins of 459 and 1,178 amino acids, respectively. Whereas the first ORF shows no significant homology to previously described proteins, the second ORF shows sequence similarities with various
Mutator
-like element (MULE)-encoded transposases, including the bacterial transposase signature sequence. Other MULE features shared by
Mutyl
include a zinc finger motif in the putative transposase, a 22-bp-long imperfect inverted repeat at each end, and a 9- to 10-bp duplication of its target site in the chromosome. Of the five copies of
Mutyl
present in the genome, one has a deletion of the first 8 bases, and the others are full length with a single base change in one element. The first potential gene of
Mutyl
,
mutB
, was shown to be expressed in exponentially growing cells. Its sequence contains a predicted intron with two 5′ splice sites, a single branch point, and two 3′ splice sites. Its mRNA is alternatively spliced, as judged by reverse transcription-PCR, and generates four mRNAs corresponding to protein-coding sequences of 128, 156, 161, and 190 amino acids. Of the three distinct lineages characterized in
Y. lipolytica
, strains from the German lineage and the French lineage do not carry
Mutyl
. A study of the distribution of
Mutyl
in strains of the French lineage evidenced a recent transposition event. Taken together, these results indicate that
Mutyl
is still active.
The pro-oxidant role of methylglyoxal in mesenteric artery smooth muscle cells
Authors: Wu Lingyun
Published: March 2005

Methylglyoxal (MG), a highly reactive metabolite of glucose, causes non-enzymatic glycation of proteins to form irreversible advanced glycation endproducts (AGEs). The present study investigated whether methylglyoxal induced oxidative stress and activated nuclear factor kappa B (NF-κB) in freshly isolated and cultured smooth muscle cells (SMCs) from rat mesenteric artery. The treatment of cells with MG (50 or 100 µmol/L) induced a significant increase in AGE formation and oxidation of DCF. MG-enhanced generation of AGEs and the oxidation of DCF was markedly inhibited by antioxidant n-acetylcysteine (NAC, 600 µmol/L). MG at a concentration of 100 µmol/L increased the heme-oxygenase-1 expression in these cells. Moreover, MG activated NF-κB p65, indicated by an increased im muno cytochemistry stain for NF-κB p65 located in the nucleus after the treatment of mesenteric artery SMCs with MG. MG-induced activation of NF-κB p65 was inhibited by NAC. In summary, MG significantly increases oxidative stress and activates NF-κB p65 in mesenteric artery SMCs. The pro-oxidant role of methylglyoxal may contribute to various pathological changes of SMCs from resistance arteries.Key words: methylglyoxal, oxidative stress, NF-κB p65, vascular smooth muscle cells, mesenteric artery.
HETEROGENEOUS ASYMMETRIC CATALYSTS: Strategies for Achieving High Enantioselection
Authors: Hutchings Graham J.
Published: March 2005

▪ Abstract  Heterogeneous asymmetric catalysis remains a topic of intense research interest because control of enantioselectivity represents one of the major synthetic challenges today. Successful strategies to achieve high enantioselection have been developed using three key approaches: (a) adsorption of chiral modifiers onto an active metal surface, which is found to be particularly effective for enantioselective hydrogenation; (b) covalent tethering of homogeneous catalysts; and (c) electrostatic interaction between a negatively charged framework and a cation. Other approaches have been advocated, e.g., encapsulation, but in general these lead to lower enantioselectivity for these heterogeneous asymmetric systems when compared with the equivalent homogeneous catalyst. This review covers the strategies for achieving high enantioselection as well as recent interesting features concerning confinement effects, the inversion of enantioselectivity, and specific cases in which enantioselection increases with conversion, all being factors that can guide researchers to identifying improved systems.
Synthesis and some reactivity studies of germanium, tin and lead analogues of alkynes
Authors: Power Philip P.
Published: March 2005

Recently published work on the syntheses and reactivity of the germanium, tin, and lead analogues of alkynes is summarized. The heavier Group 14 ‘alkynes’ are stabilized by bulky terphenyl ligands and are thermally robust crystalline solids. However, they are extremely reactive and their reactivity decreases in the order Ge > Sn > Pb. Their spectroscopy and reactivity patterns suggest that the germanium species, in particular, has considerable diradical character. This hypothesis is also supported by preliminary density functional theory calculations. Copyright © 2005 John Wiley & Sons, Ltd.
Synthesis and photochemical reactions of 1,2,7‐chalcogenadistannacycloheptanes
Authors: Saito Masaichi , Iso Kaori , Yamada Katsuhiko , Nakano Susumu , Yoshioka Michikazu
Published: March 2005

1,2,7‐Chalcogenadistannacycloheptanes were synthesized by the reactions of 1,4‐bis(bromostannyl) butane with appropriate chalcogenation reagents. Irradiation of the 1,2,7‐thiadistannacycloheptane with a low‐pressure mercury lamp (254 nm) gave 1,3,5,2,4,6‐trithiatristannin. Irradiation of 1,3,5,2,4,6‐trithiatristannin with a low‐pressure mercury lamp in the presence of either cyclotrisiloxane or 2,3‐dimethyl‐1,3‐butadiene gave a complex mixture. Copyright © 2005 John Wiley & Sons, Ltd.
Association of common ATM polymorphism with bilateral breast cancer
Authors: Heikkinen Katri , Rapakko Katrin , Karppinen Sanna‐Maria , Erkko Hannele , Nieminen Pentti , Winqvist Robert
Published: March 2005

The ATM kinase has an essential role in maintaining genomic integrity. Loss of both ATM alleles results in ataxia‐telangiectasia (A‐T), a rare autosomal recessive neuroimmunologic disorder associated with cancer susceptibility. Individuals heterozygous for germline ATM mutations have been reported to have an increased risk for malignancy, in particular, female breast cancer. In the current study, a full mutation analysis of the ATM gene was carried out in patients from 121 breast or breast‐ovarian cancer families. We discovered that the combination of 5557G→A in cis position with IVS38‐8 T→C was associated with bilateral breast cancer (OR = 10.2; 95% CI = 3.1–33.8; p = 0.001). As the 5557G→A change has been reported to affect an exonic splicing enhancer, we hypothesized that the observed composite allele could have some effect on the correct splicing of exon 39. However, no aberrant transcripts were detected, but ATM expression levels of lymphoblast cell lines from heterozygous carriers of this combination allele were lower than from noncarriers (p = 0.09). Lowered gene expression levels may have direct influence on the activities in DNA damage recognition and response pathways, as well as other genome integrity maintenance functions. Based on the results, we propose a cancer risk‐modifying effect for the ATM 5557G→A, IVS38‐8T→C composite allele. © 2005 Wiley‐Liss, Inc.
Dietary patterns and the risk of postmenopausal breast cancer
Authors: Fung Teresa T. , Hu Frank B. , Holmes Michelle D. , Rosner Bernard A. , Hunter David J. , Colditz Graham A. , Willett Walter C.
Published: March 2005

The association between individual foods and breast cancer has been inconsistent. Therefore, we examined the association between diet and risk of postmenopausal breast cancer by the alternative approach of dietary patterns. Dietary patterns were identified with factor analysis from food consumption data collected from a food frequency questionnaire in 1984. Relative risks were computed using proportional hazard models and adjusted for known risk factors for breast cancer. Between 1984 and 2000, we ascertained 3,026 incident cases of postmenopausal breast cancer. We identified 2 major dietary patterns. The prudent pattern is characterized by higher intake of fruits, vegetables, whole grains, low‐fat dairy products, fish and poultry, while the Western pattern is characterized by higher intake of red and processed meats, refined grains, sweets and desserts and high‐fat dairy products. Neither of the patterns was associated with overall risk of postmenopausal breast cancer. However, a positive association between the Western pattern score was observed among smokers at baseline (relative risk = 1.44, comparing top to bottom quintiles; 95% CI = 1.02–2.03; p for trend = 0.03). An inverse association was observed between the prudent pattern and estrogen receptor‐negative cancer (relative risk = 0.62; 95% CI = 0.45–0.88; p for trend = 0.006). Among the major food groups, higher consumptions of fruits (relative risk for 1 serving/day increase = 0.88; 95% CI = 0.80–0.97; p = 0.009) and vegetables (relative risk = 0.94; 95% CI = 0.88–0.99; p = 0.03) were significantly associated with decreased risk for ER− breast cancer. In conclusion, we did not observe an overall association between the prudent or Western pattern and overall breast cancer risk. However, a Western‐type diet may elevate risk of breast cancer among smokers, and a prudent diet may protect against estrogen receptive‐negative tumors. © 2005 Wiley‐Liss, Inc.
Pleural fluid interferon‐γ and adenosine deaminase levels in tuberculosis pleural effusion: a cost‐effectiveness analysis
Authors: Sharma S.K. , Banga Amit
Published: March 2005

Pleural fluid levels of interferon‐γ (IFN‐γ) and adenosine deaminase (ADA) have been found to be high in patients with tuberculosis (TB). The present study was carried out to compare the diagnostic utility of these two markers and to carry out a cost‐effectiveness analysis of performing IFN‐γ estimation in comparison to ADA. A total of 52 patients with pleural effusion, 35 of which were found to have TB etiology, were prospectively included for estimation of ADA and IFN‐γ levels. The difference in the cost of performing the two diagnostic tests was compared with the cost of the treatment for a patient with TB. Pleural fluid IFN‐γ (median [range]: 2,100 [70–14,000] vs. 3 [0–160]; P<0.001) as well as ADA levels (mean [SD]: 93.1 [62.3] vs 15.4 [8.7]; P<0.001) were significantly higher in patients with TB effusion. Even though IFN‐γ estimation was more sensitive (97.1 vs. 91.4%), the extra cost of IFN‐γ estimation for detecting one patient with TB was found to be equivalent to the cost of a complete course of antituberculosis treatment for six patients. In developing countries, where TB is rampant and cost is a major concern, pleural fluid IFN‐γ estimation does not seem to be a cost‐effective investigation method for differentiating TB from non‐TB pleural effusion. J. Clin. Lab. Anal. 19:40–46, 2005. © 2005 Wiley‐Liss, Inc.
Pericentric inversion of chromosome 2 and echogenic vasculature in the basal ganglia: A new finding?
Authors: Pezzati Marco , Giovannucci Maria Luisa Uzielli , Filippi Luca , Dani Carlo , Rubaltelli Firmino F.
Published: March 2005

Linear branching echogenicities in the thalamus or basal ganglia have been reported in infants with several genetic and nongenetic disorders. In this article, we report 2 cases of newborns with a neurosonographic diagnosis of thalamic/basal ganglia vasculopathy and karyotype analysis showing pericentric inversion of chromosome 2. To our knowledge, there has been no previous mention of an association between these entities. © 2005 Wiley Periodicals, Inc. J Clin Ultrasound 33:146–148, 2005
Kinetic study of polypropylene nanocomposite thermo‐oxidative degradation
Authors: Lomakin Sergei M , Dubnikova Irina L , Berezina Svetlana M , Zaikov Gennadi E
Published: March 2005

Polypropylene (PP) has wide acceptance for use in many application areas. However, low thermal resistance complicates its general practice. The new approach in thermal stabilization of PP is based on the synthesis of PP nanocomposites. This paper discusses new advances in the study of the thermo‐oxidative degradation of PP nanocomposite. The observed results are interpreted by a proposed kinetic model, and the predominant role of the one‐dimensional diffusion type reaction. According to the kinetic analysis, PP nanocomposites had superior thermal and fireproof behaviour compared with neat PP. Copyright © 2005 Society of Chemical Industry
A simple technique for the long‐term non‐polarised and polarised culture of human fallopian tube epithelial cells
Authors: Kervancioglu M.E. , Saridogan E. , Martin J.E. , Maguiness S.D. , Djahanbakhch O.
Published: March 2005

Summary— Fallopian tubes were obtained from 25 women undergoing abdominal hysterectomy. Pieces of fallopian tube mucosa were placed in culture flasks containing minimum essential medium in Earle's salts supplemented with fetal bovine serum. First passage was carried out after 7–10 days and subcultures in 4–5 days. For polarised cell culture, epithelial cells were seeded onto an extracellular matrix system. New epithelial cells were seen on day 2–3 of the primary culture and epithelial patches on day 7–10. Cells reached confluence in 4–5 days in subcultures. The cells could be subcultured for 7–11 passages with a life span of 42–60 days. Epithelial origins of the cells were confirmed by immunofluorescence staining with anti‐cytokeratin antibody. Polarised cells showed a columnar pattern, microvilli on their apical surface and basally located nucleus whereas non‐polarised cells were flat. It was concluded that the human fallopian tube epithelial cells can be cultured in vitro to create non‐polarised and polarised cell layers by using a simple and reproducible technique and this system can be a potential model to study function of the fallopian tube.
Fragmentation of International Law? Postmodern Anxieties
Authors: Koskenniemi Martti , Leino Päivi
Published: March 2005

Successive ICJ Presidents have expressed concern about the proliferation of international tribunals and substantive fragmentation of international law. This is not a new phenomenon. International law has always lacked a clear normative and institutional hierarchy. The problem is more how new institutions have used international law to further new interests, especially those not predominant in traditional law. The anxiety among ICJ judges should be seen less as a concern for abstract “coherence” than a worry about the demise of traditional principles of diplomatic law and the Court's privileged role as their foremost representative. As jurisdictional conflicts reflect divergent political priorities, it is unclear that administrative co-ordination can eliminate them. This does not, however, warrant excessive worries over fragmentation; it is an institutional expression of political pluralism internationally.
Political Dynamics of Regime Transformation in Japan in the 1990s
Authors: PARK CHEOL HEE
Published: March 2005

The 1990s is perceived in Japan as a lost decade, but it also was a decade of profound political, economic and institutional transformation. Books and articles reviewed here analyze this unprecedented change from diverse angles. Authors are in agreement that Japanese political economy has undergone major transformation in the 1990s. However, over the issue of how much and in what area those changes have occurred, authors take different standpoints. Also as to what would be the shape of future political setup, they provide us with divergent scenarios.
The Two-Party System Meets a House of Councillors Election
Authors: REED STEVEN R.
Published: March 2005

Elections to Japan's upper house, the House of Councillors, are ‘secondary’ elections, that is, elections that do not choose the government. Among the implications of this secondary status is that the party system is primarily determined elsewhere, by the system used in the general elections that do choose the government. From 1947 through 1993 the system used in general elections fostered a multiparty system that did not sit easily with the many single-member districts of the House of Councillors. Since 1996 general elections use a system based primarily on single-member districts, which is fostering a two-party system. As a two-party system emerges, we should expect the single-member districts of the upper house to become more and the multi-member districts to become less congruent with the party system. The 2004 House of Councillors election presented us with our first example of what two-party elections might look like in future upper house elections. The overall results do indeed indicate the advent of the two-party system with the major parties winning 96% of the seats in the district tier and 71% in the PR tier.
Design and Control of a Process to Extract β‐Carotene with Supercritical Carbon Dioxide
Authors: Cygnarowicz Miriam L. , Seider Warren D.
Published: March 2005

A strategy for locating optimal designs is applied to the extraction of β‐carotene with supercritical C02. With the modified Peng‐Robinson equation of state to estimate the phase equilibria, models are developed to simulate the three‐phase (solid, liquid, and supercritical fluid) extraction and separation processes. The design optimization minimizes the annualized cost while producing β‐carotene of the desired quality. The results demonstrate that despite high operating pressures, supercritical extraction can be competitive for the recovery of high‐value products at low production rates. Furthermore, the increases in solubility with small amounts of cosolvent can have a substantial impact on the economics of the proposed design. An example is given in which the addition of 1 % ethanol to the C02 solvent transforms an unfavorable design into a competitive one. In addition, a dynamic model is proposed for the product separator, and its differential‐algebraic equations are integrated with DASSL. Proportional (P) and proportional‐integral (PI) control schemes are studied to maintain the pressure by manipulating the vapor flow rate. Although the set‐point response of the PI controller is acceptable, disturbance rejection is poor. A disturbance in the feed flow rate causes lower quality β‐carotene to be produced. The desired quality is maintained when the separator is overdesigned, but this raises the annualized cost.
Multimolecular Process in a Packed‐Bed Immobilized Enzyme Reactor: Numerical Simulation and Back‐Mixing Effects
Authors: Guzy S. , Saidel G. M. , Lotan N.
Published: March 2005

In a previous report, we presented a new analytical model describing the performance of a packed‐bed catalytic unit, where the reaction between two cosubstrates is catalyzed by an enzyme immobilized on a porous carrier. The model explicitly takes into account the changes in concentrations of both cosubstrates along the reactor, as well as the hydrodynamic regimen (i.e., back‐mixing) prevailing in the packed bed. In the present report, and on the basis of the procedures developed, we present a detailed analysis of the performance of the reactor. With numerical simulations, the effects of internal diffusion limitations, the depth of the pores, the substrates' concentration in the feed, and kinetic parameters are evaluated. Particular attention is also given here to the back‐mixing effects prevailing in the reactor. An experimental procedure for assessing their extent is described.
A Method To Disperse Aggregates of a Flocculent Yeast for Photometric Analysis
Authors: Castellon‐Vogel Martha A. , Menawat Anil S.
Published: March 2005

Strategies to disperse aggregates so the cells remain in suspension long enough to take stable absorbance readings are studied. The optical density of highly flocculating yeasts, such as Saccharomyces cerevisiae ATCC 26603, drops because of cells settling to the bottom in less than 1 min. It presents a problem in using turbidimetric measurement for cell density estimate. Dilution of the yeast samples with sodium salts in a wide range of concentrations (10 mM to 1 M) disperses the aggregates, whereas dilution with calcium salts does not. ζ‐Potential measurements indicate that sodium disperses the yeast flocs by reversal of the charges on the cell surfaces. An attempt is also made to resolve the controversy about the role of sodium ions in flocculation.
Practical Method for Estimating Oxygen Kinetic and Metabolic Parameters
Authors: Cho Moo H. , Wang Shaw S.
Published: March 2005

A practical and simple method was developed to determine the oxygen kinetic and metabolic parameters of cell cultures. The said parameters are the oxygen kinetic constant (Ko2), the maximum specific oxygen uptake rate (qmax), the maximum oxygen yield (Y), the critical dissolved oxygen (DO) (Ccr), and the oxygen maintenance coefficient (mo2). These parameters can be calculated from the results of one batch fermentation run. The fermentation needs to be run at an oxygen‐limiting condition, and the profiles of DO and cell density need to be recorded. A demonstration of the use of this method was done by using a yeast, Kluyveromyces marxianus.
Enzymatic Synthesis of Biologically Active Compounds: Synthesis of Castanospermine Derivatives
Authors: Margolin Alexey L. , Delinck Deborah L.
Published: March 2005

A three‐step enzyme‐catalyzed synthesis of 7‐O‐butyrylcastanospermine from castanospermine has been developed.
λ Vectors for Stable Cloned Gene Expression
Authors: Padukone N. , Peretti S. W. , Ollis D. F.
Published: March 2005

The bacteriophage λ offers a unique opportunity concurrently to minimize segregational instability in recombinant systems by chromosomal integration of the cloned gene and to achieve high cloned gene expression during an abortive lytic phase. Lysis leads approximately to a 100‐fold amplification of the cloned gene. Cell lysis in the lytic state is blocked by a specific mutation (Sam), allowing the cell to maintain its integrity, and λ DNA packaging is blocked by other mutations (Wam, Eam) that keep cloned genes open to transcription. In the presence of these mutations, extremely high levels of cloned β‐galactosidase (more than 15% of total cell protein) have been obtained during abortive lysis from vectors found to be essentially 100% stable for over 75 generations in the lysogenic phase.
Mathematical Modeling and Simulations of Membrane Bioreactor Extractive Fermentations
Authors: Steinmeyer D. E. , Shuler M. L.
Published: March 2005

A model of extractive ethanol fermentation within a membrane bioreactor has been constructed by using a structured, nonsegregated model of Saccharomyces cerevisiae. The model has been tested by comparing actual and simulated reactor fermentations. The time‐dependent approach to steady‐state operation is well predicted. The model has also been used to examine an array of alternative operating strategies.
Characterization of the Swelling of a Size‐Exclusion Gel
Authors: Monke Karen , Velayudhan Ajoy , Ladisch Michael R.
Published: March 2005

The swelling of a dextran gel, Sephadex G‐75, was observed in an aqueous environment at room temperature by a noninvasive technique that uses light microscopy coupled to an image analysis system via a video camera. The rate of swelling was found to follow the Tanaka and Fillmore theory, from which the overall gel diffusion coefficient was estimated as 6.3 × 10−7 cm2/s. In addition to giving a quantitative measure of gel swelling that could be useful in the mechanical design of liquid chromatography columns, this approach provides data on wet particle size and particle size range, which is needed for the modeling of diffusional and mass transfer effects in size‐exclusion chromatography. In this context, key observations are that the gel particles are nearly spherical with an elliptical shape factor of 0.98 (perfect sphere=1) and that there is little difference between sizes of particles obtained in water, 50 mM Tris‐glycine buffer (pH 10.2), and buffer containing 1 mg/mL protein. The diameter of the dry material ranged from 20 to 100 μm, while the hydrated particles had diameters of 40–350 μm. The rate of swelling is rapid, with 50% swelling occurring in about 10 s and swelling to 99% of the final wet particle size being obtained in less than 90 s.
Feedback Regulation in Preparative Elution Chromatography
Authors: Frey Douglas D.
Published: March 2005

Input‐output models utilizing discrete variables are developed for elution chromatography and used together with control theory to investigate behavior patterns between output variables (e.g., yield, purity, and production rate) and input variables (e.g., cut point locations and feed slug size). Variable interactions and controllability characteristics for isocratic and stepwise gradient elution in linear and nonlinear chromatography are investigated by using the relative gain array, singular value decomposition, and direct simulation. Inverse‐based regulatory systems are evaluated for updating process inputs by using information on process outputs such that product quality and system performance parameters are efficiently maintained for the case where the column is overloaded and the solute peaks overlap with each other. Strategies for feedback optimizing control are also discussed.
Growth, Metabolic, And Antibody Production Kinetics Of Hybridoma Cell Culture: 1. Analysis Of Data From Controlled Batch Reactors
Authors: Ozturk Sadettin S , Palsson Bernhard O
Published: March 2005

A mouse‐mouse hybridoma cell line (167.4G5.3) was cultivated in a 1.5‐L stirred‐tank bioreactor under constant pH and dissolved oxygen concentration. The transient kinetics of cell growth, metabolism, and antibody production were followed by biochemical and flow cytometric methods. The cell‐specific kinetic parameters (growth and metabolic rates) as well as cell size were constant throughout the exponential phase. Intracellular protein and RNA content followed a similar trend. Cell growth stopped when the glutamine in the medium was depleted. Glucose could not substitute for glutamine, as glucose consumption ceased after glutamine depletion. Ammonia and lactate production followed closely glutamine and glucose consumption, respectively. Alanine, glutamate, serine, and glycine were produced but other amino acids were consumed. The cells are estimated to obtain about 45% of the total energy from glycolysis, with the balance of the metabolic energy provided by oxidative phosphorylation. The antibody was produced at a constant rate in both the exponential and decline phases of growth. The intracellular antibody content of the cells remained relatively constant during the exponential phase of growth and decreased slightly afterwards.
Kinetics of Peroxidase Production by Streptomyces viridosporus and Recombinant Streptomyces lividans
Authors: Korus Roger A , Lodha Sanjay J , Adhi Tri P , Crawford Don L.
Published: March 2005

The production of peroxidases by Streptomyces viridosporus T7A and recombinant Streptomyces lividans TK64.1 was characterized in stirred tank fermentors. The rate of peroxidase production was strongly growth associated with plasmid‐coded S. lividans, in contrast to chromosome‐coded S. viridosporus, where peroxidase production was proportional to cell mass rather than cell growth rate. A modified form of the logistic equation gave a good fit to the experimenal data for cell growth and peroxidase formation.
Model for Transient Moisture Profiles of a Drying Apple Slab Using the Data Obtained with Magnetic Resonance Imaging
Authors: Mccarthy Michael J , Perez Ernest , Özilgen Mustafa
Published: March 2005

The use of magnetic resonance imaging (MRI) spectroscopy as a real time probe to noninvasively obtain transient moisture profiles during food dehydration is demonstrated. A laboratory‐scale wind tunnel drier was constructed. A 2 × 5 × 5 cm3 apple slab was inserted in the probative zone and one‐dimensional drying was effected at quasiisothermal conditions. Spatial resolution of 0.60 mm was obtained. The transient moisture profiles were simulated with a simple mass transfer model. Effective diffusivity of water in the apple was calculated as 8.3 × 10−5 cm2/s.
Nonlinear Gradient Isotherm Parameter Estimation for Proteins with Consideration of Salt Competition and Multiple Forms
Authors: Whitley Roger D , Berninger James A , Rouhana Nathalie , Wang N.‐H Linda
Published: March 2005

Salt gradients in ion‐exchange chromatography are routinely used to speed separation of proteins and to concentrate products, but systematic optimization of these gradients requires protein equilibrium data as a function of salt concentration. An understanding of conformational changes, aggregation, and salt effects, which include both competition and affinity modulation, is important for equilibrium isotherm parameter estimation. In this study, gradient elution of bovine serum albumin (BSA) in anion exchange was well predicted by a salt‐modulated nonlinear isotherm which considers salt competition. The isotherm was able to predict BSA gradient elution from batch equilibrium data. The same isotherm was also able to predict elution for various gradient slopes when fitted to an intermediate slope gradient experiment. If multiple forms due to aggregation or denaturation exist, isotherm parameters are readily averaged in batch experiments because of the long equilibration times. Similarly, gradient experiments yield averaged parameters because the salt gradient tends to merge the closely eluting forms. However, in isocractic elution, if the reaction rate is not rapid enough to give a merged peak, the estimated isotherm parameters are only fair predictors of gradient behavior and vice versa. Slower flow rates in isocratic elution can help reduce the discrepancy by allowing forms to merge through interconversion. As an alternative to determining averaged parameters, consideration of two binding forms, using VERSE‐LC, an advanced rate model, gave good agreement with experimental data over the entire range of salt gradient durations.
Effective Diffusivity of Galactose in Calcium Alginate Gels Containing Immobilized Zymomonas mobilis
Authors: Korgel Brian A. , Rotem Abraham , Monbouquette Harold G.
Published: March 2005

The effective diffusivity of galactose was measured for calcium alginate gel membranes containing immobilized live Zymomonas mobilis cells at concentrations ranging from 0 to 150 g dry wt/L of gel. Since galactose is not taken up by living Z. mobilis organisms, the diffusion of this representative six‐carbon sugar could be studied independently of sugar consumption. Various immobilized biomass loadings were achieved by two different techniques: addition of biomass at known concentrations to the sodium alginate solution before membrane formation and growth of cells in the gel to various biomass concentrations. The highest immobilized cell concentration, attained by in situ growth, corresponds to the maximum for this system, as growth beyond this maximum concentration led to disintegration of the gel membrane. The galactose effective diffusivity measurements for both methods of immobilized cell loading overlap within experimental error and follow the same general monotonic decline with entrapped biomass concentration. Most of the data fall below the upper bound predicted by Hashin and Shtrikman (1962) and show good agreement with the random pore model of Wakao and Smith (1962, 1964). Available effective diffusivity data from the literature provide evidence that the random pore model is an excellent predictor of sugar effective diffusivity in gel immobilized cell systems in general.
Enzymatic Regulation of Glucose Catabolism by Lactobacillus plantarum in an Aerobic Chemostat
Authors: Tseng Ching‐Ping , Montville Thomas J.
Published: March 2005

The influence of oxygen on the metabolic regulation of glucose catabolism by Lactobacillus plantarum 8014 was examined in a chemostat (D=0.2 h−1, pH 5.5). A steadystate anaerobic culture was shifted to an aerobic condition by imposing an oxygen transfer rate of 1.84 mmol L−1 min−1. Enzyme activities, end product concentrations, and ATP levels were determined during the resultant transition and under steady‐state aerobic conditions. During the transition, oxygen was consumed by the aerobic culture and the intracellular ATP concentration increased until hydrogen peroxide, which also increased, became inhibitory. Under the aerobic condition, the steady‐state specific rate of substrate utilization and acetate production increased. The lactate dehydrogenase, NAD‐dependent lactate dehydrogenase, acetate kinase, pyruvate oxidase, and NADH oxidase specific activities all increased under aerobic conditions. Changes in the intracellular lactate and acetate concentrations had a temporal correspondence with the changes in the aforementioned catabolic activities. Subsequent experiments using chloramphenicol to inhibit de novo protein synthesis and kinetic analysis of crude enzyme extracts suggested that these changes were due to both changes in synthesis and activity levels.