bluuebunny/crossref_metadata_2025 huggingface dataset:
Previously uncharacterized isoforms of divalent metal transporter (DMT)-1: Implications for regulation and cellular function
Authors: Hubert Nadia , Hentze Matthias W.
Published: September 2002

Divalent metal transporter 1 (DMT1) mediates apical iron uptake into duodenal enterocytes and also transfers iron from the endosome into the cytosol after cellular uptake via the transferrin receptor. Hence, mutations in DMT1 cause systemic iron deficiency and anemia. DMT1 mRNA levels are increased in the duodenum of iron-deficient animals. This regulation has been observed for DMT1 mRNA harboring an iron–responsive element (IRE) in its 3′ UTR, but not for a processing variant lacking a 3′UTR IRE, suggesting that the IRE regulates the expression of DMT1 mRNA in response to iron levels. Here, we show that iron regulation of DMT1 involves the expression of a previously unrecognized upstream 5′ exon (exon 1A) of the human and murine DMT1 gene. The expression of this previously uncharacterized 5′ exon is tissue-specific and particularly prevalent in the duodenum and kidney. It adds an in-frame AUG translation initiation codon extending the DMT1 ORF by a conserved sequence of 29–31 amino acids. In combination with the IRE- and non-IRE variants in the 3′UTR, our results reveal the existence of four DMT1 mRNA isoforms predicting the synthesis of four different DMT1 proteins. We show that two regulatory regions, the 5′ promoter/exon 1A region and the IRE-containing terminal exon participate in iron regulation of DMT1 expression, which operate in a tissue-specific way. These results uncover an unexpected complexity of DMT1 expression and regulation, with implications for understanding the physiology, cell biology, and pathophysiology of mammalian iron metabolism.
Molecular cloning and functional expression of the first insect FMRFamide receptor
Authors: Cazzamali Giuseppe , Grimmelikhuijzen Cornelis J. P.
Published: September 2002

FMRFamide and FMRFamide-related neuropeptides are extremely widespread and abundant in invertebrates and have numerous important functions. Here, we have cloned a
Drosophila
orphan receptor, and stably expressed it in Chinese hamster ovary cells. Screening of a peptide library revealed that the receptor reacted with high affinity to FMRFamide (EC
50
, 6 × 10
−9
M). The intrinsic
Drosophila
FMRFamide peptides are known to be synthesized as a large preprohormone, containing at least 13 related FMRFamide peptides (8 distinct FMRFamides). Screening of these intrinsic
Drosophila
FMRFamides showed that the receptor had highest affinity to
Drosophila
FMRFamide-6 (PDNFMRFamide) (EC
50
, 9 × 10
−10
M), whereas it had a somewhat lower affinity to
Drosophila
FMRFamide-2 (DPKQDFMRFamide) (EC
50
, 3 × 10
−9
M) and considerably less affinity to the other
Drosophila
FMRFamide-related peptides. To our knowledge, this article is the first report on the molecular identification of an invertebrate FMRFamide receptor.
Electron energy distribution function (0-40 eV range) in helium in transverse hollow-cathode discharge used for lasers
Authors: J Mizeraczyk  , W Urbanik
Published: September 2002

The authors present results of measurements of the electron energy distribution function (EEDF) in the range of 0-40 eV for the plasma of a transverse hollow-cathode discharge in helium as used in laser technology. The measurement technique employs the second derivative of the electric probe current-voltage characteristic. The results show that the EEDF for the transverse hollow-cathode discharge is neither Maxwellian nor Druyvesteynian and the influence of some elementary processes on the shape of the EEDF is discernible. The presence of the EEDF maximum at 26 eV is believed to suggest the importance of recombination in atomic processes occurring inside a hollow cathode.
Light-Intensity-Dependent Expression of Lhc Gene Family Encoding Light-Harvesting Chlorophyll-a/b Proteins of Photosystem II in Chlamydomonas reinhardtii
Authors: Teramoto Haruhiko , Nakamori Akira , Minagawa Jun , Ono Taka-aki
Published: September 2002

Excessive light conditions repressed the levels of mRNAs accumulation of multiple Lhc genes encoding light-harvesting chlorophyll-a/b (LHC) proteins of photosystem (PS)II in the unicellular green alga, Chlamydomonas reinhardtii. The light intensity required for the repression tended to decrease with lowering temperature or CO2concentration. The responses of six LhcII genes encoding the major LHC (LHCII) proteins and two genes (Lhcb4 andLhcb5) encoding the minor LHC proteins of PSII (CP29 and CP26) were similar. The results indicate that the expression of theseLhc genes is coordinately repressed when the energy input through the antenna systems exceeds the requirement for CO2 assimilation. The Lhc mRNA level repressed under high-light conditions was partially recovered by adding the electron transport inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea, suggesting that redox signaling via photosynthetic electron carriers is involved in the gene regulation. However, the mRNA level was still considerably lower under high-light than under low-light conditions even in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea. Repression of theLhc genes by high light was prominent even in the mutants deficient in the reaction center(s) of PSII or both PSI and PSII. The results indicate that two alternative processes are involved in the repression of Lhc genes under high-light conditions, one of which is independent of the photosynthetic reaction centers and electron transport events.
Synthesis, Structural Preference and Catalytic Activity of Neutral and Cationic Methylpalladium(II) Complexes Containing N-Arylpyridine-2-carbaldimine Chelating Ligands
Authors: Arnaiz Ana , García-Herbosa Gabriel , Cuevas José V. , Lavastre Olivier , Hillairet Caroline , Toupet Loïc
Published: September 2002

The syntheses and structures of neutral complexes [PdCl(Py-2-CH=NAr)(Me)] (Ar = 4-MeC6H4, 4-MeOC6H4, 4-CF3C6H4) and cationic complexes [Pd(Py-2-CH=NAr)(Me)(MeCN)]SbF6 (Ar = 4-MeC6H4, 4-MeOC6H4, 4-CF3C6H4) are described. The preference for the trans-isomers in the cationic complexes and for the cis-isomers in the neutral complexes is discussed on the basis of electronic arguments and supported by DFT calculations. The observed preference seems to follow the maximum hardness principle (MHP) introduced by Pearson. On the basis of the application of this principle to square planar complexes of palladium(II) and platinum(II) we propose the trans choice, which means that the hardest ligand arranges trans to the softest one. The synthesis and crystal structure of the related neutral complex trans-[Pd(CF3COO)(Py-2-CH=NC6H4-4-OMe)(Me)] is also described and allows to rule out the charge of the complex as the cause of isomeric preference. We also report our preliminary studies dealing with the catalytic activity of the cationic complexes in alkene oligomerization and copolymerization with CO.
ON SIGNATURES OF SHORT DISTANCE PHYSICS IN THE COSMIC MICROWAVE BACKGROUND
Authors: BRANDENBERGER ROBERT H. , MARTIN JÉRÔME
Published: September 2002

Following a self-contained review of the basics of the theory of cosmological perturbations, we discuss why the conclusions reached in the recent paper by Kaloper et al.1 are too pessimistic estimates of the amplitude of possible imprints of trans-Planckian (string) physics on the spectrum of cosmic microwave anisotropies in an inflationary universe. It is shown that the likely origin of large trans-Planckian effects on late time cosmological fluctuations comes from nonadiabatic evolution of the state of fluctuations while the wavelength is smaller than the Planck (string) scale, resulting in an excited state at the time that the wavelength crosses the Hubble radius during inflation.
QUANTUM GROUP SYMMETRY OF INTEGRABLE SYSTEMS WITH OR WITHOUT BOUNDARY
Authors: RAGOUCY E.
Published: September 2002

We present a construction of integrable hierarchies without or with boundary, starting from a single R-matrix, or equivalently from a ZF algebra. We give explicit expressions for the Hamiltonians and the integrals of motion of the hierarchy in term of the ZF algebra. In the case without boundary, the integrals of motion form a quantum group, while in the case with boundary they form a Hopf coideal subalgebra of the quantum group.
PATTERN FORMATION IN METAL ON METAL EPITAXY
Authors: HWANG R. Q. , BEHM R. J.
Published: September 2002

With the application scanning tunneling microscopy to the field of metal on metal epitaxy, the precise forms of the two dimensional islands initially created can be studied in great detail. A variety of shapes have been discovered. By carefully studying the effect of growth parameters and quantitatively analyzing the resultant shapes, the details of the atomistic processes governing the pattern formation can be extracted. In the paper we review several examples of this type of study.
FRACTAL SURFACES IN ENGINEERING: APPLICATIONS OF DYNAMIC SCALING
Authors: FAMILY FEREYDOON
Published: September 2002

This talk will be a review of some of the fundamental ideas behind dynamic scaling of fractal surfaces and how it can be used to characterize the evolution and the morphology of surfaces in engineering related problems. After a brief review, two different applications of dynamic scaling will be discussed. The first is the problem of fluid flow in porous media, and the second example will be the problem of how to describe thin film growth by MBE techniques. These examples should illustrate the generality of the method and its applicability to a wide range of problems in surface science and engineering.
SCALING PROPERTIES OF THE SCATTERING COEFFICIENTS FOR MUTUALLY SELF-SIMILAR GELS
Authors: DOGARIU A. , UOZUMI J. , ASAKURA T.
Published: September 2002

The observable quantities in an optical experiment are influenced by the fractal dimension and the average cluster size of mutually self-similar gels. We study the scaling properties of the scattering and the transport mean free path in order to use them for the microscopical characterization of fractal gels.
SCALING OF FLUID RECOVERY FROM PERCOLATION FRACTALS
Authors: WEDGWOOD IAN D , MONRO DONALD M
Published: September 2002

We report on the recovery of fluid driven through percolation lattices across a range of scales using a finite difference approximation to the Navier-Stokes equation. This is important in the study of recovery from petroleum reservoirs, in which flow occurs over a wide range of scales, from the microscopic pores right up to the full reservoir. This variation of scale presents difficulties, since flow at the pore level is subject to predominantly viscous effects, whereas at the larger scales the viscous effects may become negligible in comparison with inertial effects. The Navier-Stokes equations may differ greatly with scale. Theoretical rock structures are created using percolation lattices and the flow properties of identical rock structures are then examined as a function of scale. The resultant recovery rates exhibit similarity across scale which would simplify the study of geological reservoir models.
ANALYSIS OF A HIGH-SPEED INTERCONNECTION NETWORK
Authors: MIR NADER F.
Published: September 2002

A thorough routing analysis of a switching network called the spherical switching network for high-speed applications is presented in this paper. The spherical switching network has a cyclic, regular, and highly expandable structure with a simple self-routing scheme. The network is constructed with fixed-size switch elements regardless of the size of the network. Each switch element consists of a carefully-selected sized 9 input/output crossbar and a local controller. One of the nine pairs of links is external and carries the external traffic, and the other eight pairs are internal. The contention resolution in each switch element is based on deflection of losing packets and incremental priority of packets. The switch elements do not utilize any buffering within the network. The analysis shows that this network clearly outperforms typical interconnection networks currently being deployed in practical switches and routers such as Banyan network. In order to keep the number of deflections low, each incoming external link is connected to a buffer with flow control capabilities. Due to the special arrangement of interconnections in the network, a much larger number of shortest paths between each pair of source/destination exists. The related analysis for finding the number of hops and shortest paths appear in this paper.
TIME-OPTIMAL PATH PLANNING AND CONTROL USING NEURAL NETWORKS AND A GENETIC ALGORITHM
Authors: CHAIYARATANA NACHOL , ZALZALA ALI M. S.
Published: September 2002

This paper presents the use of neural networks and a genetic algorithm in time-optimal control of a closed-loop 3-dof robotic system. Extended Kohonen networks which contain an additional lattice of output neurons are used in conjunction with PID controllers in position control to minimize command tracking errors. The extended Kohonen networks are trained using reinforcement learning where the overall learning algorithm is derived from a self-organizing feature-mapping algorithm and a delta learning rule. The results indicate that the extended Kohonen network controller is more efficient than other techniques reported in early literature when the robot is operated under normal conditions. Subsequently, a multi-objective genetic algorithm (MOGA) is used to solve an optimization problem related to time-optimal control. This problem involves the selection of actuator torque limits and an end-effector path subject to time-optimality and tracking error constraints. Two chromosome coding schemes are explored in the investigation: Gray and integer-based coding schemes. The results suggest that the integer-based chromosome is more suitable at representing the decision variables. As a result of using both neural networks and a genetic algorithm in this application, an idea of a hybridization between a neural network and a genetic algorithm at the task level for use in a control system is also effectively demonstrated.
FEMALE RESISTANCE AND MATING OUTCOMES IN A STREAM-DWELLING ISOPOD: EFFECTS OF MALE ENERGY RESERVES AND MATING HISTORY
Authors: Sparkes Timothy , Keogh Daniel , Orsburn Tyler
Published: September 2002

In the stream-dwelling isopod, Lirceus fontinalis, conspicuous mating contests occur between males and females prior to pair formation. Our previous work has shown that female resistance during contests determines contest outcomes. Here we examined whether female resistance could act as a mechanism of choice in which females discriminate against males with low energy (glycogen) reserves. We manipulated male glycogen levels by chasing males around a race-track then exposed females to males that differed in glycogen levels. We found that high-glycogen males were more successful than low-glycogen males and that this effect appeared to be due to increased female resistance towards low-glycogen males. We then examined one potential benefit to females of energy-based mate discrimination. In L. fontinalis, male mating history and levels of glycogen reserves are correlated, i.e. recently mated males are glycogen-depleted due to energy costs associated with mating. We examined whether recently mated males were also costly mates, and thus should be avoided by females. We quantified the relationship between male mating history and female fertilization success and found that females suffered an 18% reduction in fertilization success by mating with a male that had recently inseminated another female. We propose that female resistance could act as a mechanism of choice in which males with low energy reserves are avoided and that one benefit of this discrimination is that females increase fertilization success be avoiding males that have recently mated.
Photodissociation of Small Molecules in the Gas Phase
Authors: Kawasaki Masahiro , Bersohn Richard
Published: September 2002

Our knowledge of the process of photodissociation is built on a foundation of molecular spectroscopy developed since the 1920’s. However, modern photodissociation dynamics has been mainly created by the introduction of laser light sources around 1970. This review of molecular photodissociation emphasizes findings based on techniques developed in the past ten–fifteen years. These include measurement of the energy dependence of the branching ratios of the yields of different photodissociation channels and the distribution of velocity and internal states of the fragments. The time scale of the separation of the fragments is shown to vary from the microsecond to the femtosecond regime depending on whether the dissociation is indirect or direct. Multiphoton dissociation can be incoherent or coherent. In the latter case, if two different optical paths can accomplish dissociation, changing the relative phase of the transition matrix elements of the two paths can control the branching ratio of different channels. The branching ratio can also be controlled by aligning the parent molecule in an electric field or by using successive ultraviolet and infrared transitions. The review concludes with some applications of photodissociation to the terrestrial atmosphere and to the generation of reactive radical sources.
Counter Ion Release of Ionic Surfactant Micelles Induced by Solubilized Amphiphiles: Size Effect of a Polar Head Group
Authors: Manabe Masahiro , Kaneko Miharu , Miura Takako , Akiyama Chinami , Kawamura Hideo , Katsuura Hajime , Shiomi Masaki
Published: September 2002

The acceleration rate (dα/dXam) of the dissociation degree (α) of ionic SDS micelles to the mole fraction (Xam) of solubilized additives has been determined at infinite dilution by a differential conductivity method. The additives used were a homologous series of amphiphiles with different types of polar groups: alkylglucosides, MEGAs, diols, and cyclooctanol. The method allows us to determine the partition coefficient between the bulk water and the micelles (Kx) and the rate of depression (Csf/Caf) of the monomer surfactant concentration (Csf) to the monomer additive (Caf), in addition to dα/dXam. The results are as follows: (1) dα/dXam in each homologous series is independent of the alkyl chain length, indicating a characteristic value of each polar group. (2) dα/dXam increases with increasing molecular weight of the groups, representing the size effect on the counter ion dissociation. (3) For diols, dα/dXam is higher than twice that of 1-alkanols, due to a large effective size. (4) Kx is dependent on the alkychain length, but independent of the polar group types, indicating that the net charge on the surface of the micelles remains unaltered by solubilization. (5) (Csf/Caf) determined above cmc is identical with the cmc decreasing rate, Δcmc/ΔCa, at cmc.
Detection of Ligand-Substitution Intermediates in the Photoreactions of Bis(2,2′-bipyridine)butanediamineruthenium(II) Complex Using Electrospray Ionization Mass Spectrometry
Authors: Arakawa Ryuichi , Abe Kazuyuki , Abura Tsutomu , Nakabayashi Yasuo
Published: September 2002

The photolysis of [Ru(bpy)2(bn)]2+ (bpy = 2,2′-bipyridine, bn = 1,4-butanediamine) in acetonitrile and acetone by light of wavelength longer than 420 nm was studied by electrospray ionization mass spectrometry (ESI-MS). The results were different from those of two other amine complexes, [Ru(bpy)2(en)]2+ and [Ru(bpy)2(tn)]2+ (en = ethylenediamine and tn = 1,3-propanediamine). An analysis of the irradiation time course revealed that one end of the bn ligand is quickly dissociated to form a solvent-coordinated complex, [Ru(bpy)2(bn)(AN)]2+ (AN = acetonitrile), and its protonated complex, [Ru(bpy)2(bn + H)(AN)]3+. These solvent-coordinated complexes were not observed in the photochemical reactions of the en or tn complex. The difference in photolysis is due to the fact that the coordination of the bn ligand in [Ru(bpy)2(bn)]2+ is less stable than the en or tn ligand. Both the en and tn complexes formed oxygenated complexes, while the bn complex did not form such a complex. This can be explained by the incorporation of singlet oxygen during the photochemical reaction.
Mechanism for Photocleavage of N-(Anthroyloxy)-9-fluorenylideneamines and Dynamic Behavior of Anthroyloxyl Radicals
Authors: Saitoh Yasuo , Kaneko Makoto , Segawa Katsunori , Itoh Hiroki , Sakuragi Hirochika
Published: September 2002

Photocleavage of the N–O bond of N-(9-anthroyloxy)-9-fluorenylideneamine and its 1-and 2-anthroyloxy derivatives takes place efficiently in acetonitrile in the excited singlet state attributed to the fluorenylidene moiety. This made it possible for the first time to directly observe anthroyloxyl radicals by the transient absorption method. The quantum efficiency for photocleavage decreases remarkably in benzene, in which the lowest excited singlet state is attributed to the anthroate moiety. All the three kinds of anthroyloxyl radicals are much less reactive in decarboxylation, addition to olefins, and hydrogen-atom abstraction than benzoyloxyl and 1- and 2-naphthoyloxyl radicals; 9-anthroyloxyl radicals supposedly undergo intramolecular addition–elimination in the ipso-position in equilibrium with α-lactonic spirodihydroanthryl radicals, as indicated by one-color and two-color laser photolyses.
Triethylborane Induced Radical Reaction of Gallium Enolates with α -Halo Esters
Authors: Usugi Shin-ichi , Yorimitsu Hideki , Shinokubo Hiroshi , Oshima Koichiro
Published: September 2002

Treatment of silyl enolates with methyllithium followed by an addition of gallium trichloride afforded the corresponding gallium enolates. The reaction of the resulting gallium enolates with α-halo carbonyl compounds in the presence of triethylborane as a radical initiator provided 1,4-dicarbonyl compounds in good yields.
Electronic Characterization of Dimethyl 1,2-Dihydropyrrolo[1,2-a] quinoxaline-2,3-dicarboxylate in Solution and in the Solid State
Authors: Hirano Keisuke , Yamaoka Seiji , Minakata Satoshi , Komatsu Mitsuo
Published: September 2002

Dimethyl 1,2-dihydropyrrolo[1,2-a]quinoxaline-2,3-dicarboxylate is red colored in the solid state, while it is a small molecule and has no hydrogen-bonding interaction. This unusual color property was investigated by means of electronic characterization in solution and in the solid state. The push-pull system from electron-donating pyrrole nitrogen to the electron-withdrawing 3-methoxycarbonyl moiety causes a spectral shift to an orange color in the visible region. An X-ray structure analysis indicated that these polar molecules (μ = 7.6 D) are arranged in a zig-zag fashion so as to minimize the electrostatic energy. As a consequence, the absorption band is presumably shifted toward longer wavelengths by about 60 nm (about 2508 cm−1) in going from a solution to the solid state. These results lead to a large bathochromic shift in the absorption spectrum, resulting in the red color of this compound in the solid state.
Photochromism of 2-Hydroxychalcones in Solid Hydrogel Matrices
Authors: Matsushima Ryoka , Kato Katsuaki , Ishigai Shinichi
Published: September 2002

Photochromic reactions of some substituted 2-hydroxychalcones [3-(2-hydroxyphenyl)-1-phenyl-2-propen-1-ones] have been studied in solid hydrogel matrices. The results demonstrated good reversibilities for the chalcone-flavylium interconversion. Thus, in an agar-gel matrix the coloration-decoloration could be repeated over 50 cycles without significant fatigue. In a silica sol-gel matrix, a fairly good reversibility was obtained up to ca. 30 cycles; in the later cycles, however, extensive degradations took place.
Graphical Tools for Comparative Genome Analysis
Authors: Dicks Jo
Published: September 2002

Visualization of data is important for many data-rich disciplines. In biology, where data sets are becoming larger and more complex, grephical analysis is felt to be ever more pertinent. Although some patterns and trends in data sets may only be determined by sophisticated computional analysis, viewing data by eye can provide us with an extraordinary amount of information in an instant. Recent advances in bioinformatic technologies allow us to link graphical tools to data sources with ease, so we can visualize our data sets dynamically. Here, an overview of graghical software tools for comparative genome analysis is given, showing that a range of simple tools can provide us with powerful view of the differences and similarities between genome.
Efficient photoinduced electron transfer between C60/C70 and zinc octaethylporphyrin studied by nanosecond laser photolysis method
Authors: EL-KHOULY MOHAMED E. , FUJITSUKA MAMORU , ITO OSAMU
Published: September 2002

Photoinduced electron-transfer processes between C 60 or C 70 and zinc octaethylporphyrin ( ZnOEP ) have been studied in polar solvents with the nanosecond laser flash photolysis method, observing the transient absorption spectra in the visible and near-IR regions. By the predominant excitation of ZnOEP with 532 nm laser light the transient absorption bands of 3 ZnOEP * decayed, accompanied by the appearance of the transient absorption bands of [Formula: see text] and [Formula: see text]. By the predominant excitation of C 60 and C 70 with 610 nm laser light the decays of [Formula: see text] and [Formula: see text] were observed, accompanied by the appearance of [Formula: see text] and [Formula: see text]. The electron transfer rate constants (k et ) and the quantum yields (Φ et ) of [Formula: see text] and [Formula: see text] formation via 3 ZnOEP * and [Formula: see text] or [Formula: see text] have been evaluated. These values increase with the solvent polarity; in polar benzonitrile these values are higher than for other porphyrins such as zinc tetraphenylporphyrin. The back electron transfer rate constants were evaluated from the decays of [Formula: see text] and [Formula: see text], which also show a solvent polarity dependence.
Working with parents of aggressive children: A practitioner’s guide
Authors: Dempsey Margaret T.
Published: September 2002

by Timothy A. Cavell. Washington, DC: American Psychological Association, 2000, 265 pp.
An exploratory study on self‐evaluated aggression and androgens in women
Authors: von der Pahlen Bettina , Lindman Ralf , Sarkola Taisto , Mäkisalo Heikki , Eriksson C.J. Peter
Published: September 2002

Healthy, premenopausal women completed the Buss‐Perry Aggression Questionnaire. Venous blood samples were taken at the mid‐cycle phase of the menstrual cycle to determine plasma androgen levels. Total and free testosterone, 5α‐dihydrotestosterone, androstenedione, and dehydroepiandrosterone were assessed. Path analyses were aimed at finding out which of the five circulating hormones might best predict a latent aggression construct derived from the four subscales of the Aggression Questionnaire. A significant correlation was found between free testosterone and physical and verbal aggression subscales. In addition, the results demonstrate for the first time in women a significant link between 5α‐dihydrotestosterone and anger. Thus, both testosterone and 5α‐dihydrotestosterone may affect, by separate pathways, the basal regulation of aggression‐proneness in women. Aggr. Behav. 28:273–280, 2002. © 2002 Wiley‐Liss, Inc.
Motor activity in group‐housed and isolated mice with short and long attack latencies: Effects of scopolamine
Authors: Moragrega I. , Carrasco M.C. , Vicens P. , Redolat R.
Published: September 2002

Isolation‐induced behavioral changes are well described in mice, although few studies have investigated the involvement of the cholinergic system in these effects. It has also been suggested that mice that display short or long attack latencies show differences in their reactions to a novel environment. The purpose of the present study was, first, to investigate locomotor activity in grouped and isolated mice that displayed short or long attack latencies and, second, to evaluate locomotor activity to determine whether it was affected interactively by differential housing and scopolamine treatment. Two experiments were performed in which NMRI mice, either isolated or group housed, were used as subjects. In the first experiment, results showed that there were no significant differences in locomotor activity between isolated mice with short and long attack latencies, although both groups were more active than grouped mice. These results indicate that motor activity in NMRI mice is influenced by housing conditions but not by levels of aggressiveness. In the second experiment it was observed that scopolamine (1 mg/kg) increased total activity counts both in isolated and group‐housed mice (both groups selected with long attack latencies), suggesting that differential housing in this strain does not substantially modify the motor effects of this dose of scopolamine. Aggr. Behav. 28:328–336, 2002. © 2002 Wiley‐Liss, Inc.
Convergence of control performance by unfalsification of models—levels of confidence
Authors: Veres S. M.
Published: September 2002

A general framework is introduced for iterative/adaptive controller design schemes by model unfalsification. An important feature of the schemes is their convergence near to the best possible controller given a set of model and controller structures. The problem of stability assured controller tuning is examined through unfalsified Riemannian bands of the Nyquist plot. Instability tolerantH∞andl1‐norm‐based controller tuning schemes are introduced. Computational problems are discussed and a simulation is used to illustrate the new scheme. Copyright © 2001 John Wiley & Sons, Ltd.
Force control of a reciprocating surface grinder using unfalsification and learning concept
Authors: Ali Razavi H. , Kurfess Thomas R.
Published: September 2002

A plant model is an essential requirement in conventional methods for controller synthesis. However, it is possible to find a set of controllers that are not falsified by the performance specification or the measured data without any plant model or prejudicial assumptions. This concept is used to select and implement a force controller for a reciprocating surface grinder. Copyright © 2001 John Wiley & Sons, Ltd.
Subspace based direct adaptive ℋ︁∞control
Authors: Woodley Bruce R. , How Jonathan P. , Kosut Robert L.
Published: September 2002

This paper presents extensions of the model free subspace based ℋ︁∞control approach. In particular, a fast algorithm for computing a subspace predictor from experimental data is introduced. The paper also describes a fast algorithm for updating the subspace predictor when new experimental data are available. These algorithms can be applied in conjunction with model free subspace based ℋ︁∞control in order to create a novel adaptive control law. A defining feature of this control law is that an estimate of achievable performance is maintained throughout the operation of the closed‐loop system. These algorithms are used to demonstrate the closed‐loop control of a flexible structure. Copyright © 2001 John Wiley & Sons, Ltd.
Modification of polypropylene by melt vibration blending with ultra high molecular weight polyethylene
Authors: Wang Kejian , Zhou Chixing , Zhang Hongbin , Zhao Delu
Published: September 2002

A novel vibration internal mixer was used to prepare polypropylene/ultra high molecular weight polyethylene PP/UHMWPE blends with two additional adjustable processing parameters (vibration frequency and vibration amplitude) as compared with those prepared in the steady mode. Microscopy, mechanical tests, and differential scanning calorimetry showed that vibration influenced the blend morphology and the product properties. The good phase homogeneity of the blends might be due to the variation of shear rate either spatially or temporally in blending. Additionally, the vibration internal mixer could be used to analyze the dependency of viscosity on the shear rate. Vibration enhanced the interpenetration of UHMWPE into PP and vice versa. Subsequently, the formed crystals of two components were connected, and there was epitaxy between PP and UHMWPE crystals. Moreover, the crystalline aggregates, with the amorphous UHMWPE, formed a complex network‐like continuous structure, which improved the elongation ratio at the break and the yield strength. The higher the vibration frequency and/or the larger the vibration amplitude at a fixed average rotation speed of the mixer, the more significant these effects were. The larger amount of the connected crystals, especially of β form of PP in the bulk α form PP as well as with the continuous phase structure, led to a higher tensile properties of PP/UHMWPE vibration blended. © 2002 Wiley Periodicals, Inc. Adv Polym Techn 21: 164–176, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/adv.10020
Simplified model of stress‐induced crystallization kinetics of polymers
Authors: Guo Jianxin , Narh Kwabena A.
Published: September 2002

A stress‐induced crystallization model for semicrystalline plastics is proposed based on the theory that stress‐induced orientation of molecules and chains increase the melting temperature of thermoplastics, and hence, the supercooling which is the driving force for crystallization. By assuming that the effect of stress on crystallization is only by increasing the melting temperature, the basic quiescent‐state crystallization equation can be directly applied to model stress‐induced crystallization kinetics. The model has a minimum of experimentally based constants. A simple experimental technique, such as a rotational rheometer, can be used to determine the melting temperature shift. The model predicts the most prominent features of stress‐induced crystallization. The main advantage of the model is that the parameters in the quiescent‐state crystallization model do not change. Consequently, the parameters in the melting temperature shift model are easy to determine, and unknown constants are kept to a minimum. © 2002 Wiley Periodicals, Inc. Adv Polym Techn 21: 214–222, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/adv.10022
The Hypersensitivity Pneumonitis Diagnostic Index: Use of non‐invasive testing to diagnose hypersensitivity pneumonitis in metalworkers
Authors: Dangman Kenneth H. , Cole Solon R. , Hodgson Michael J. , Kuhn Charles , Metersky Mark L. , Schenck Paula , Storey Eileen
Published: September 2002

Background

Since 1993, several outbreaks of hypersensitivity pneumonitis (HP) have been reported in metalworkers. We report the largest outbreak of HP in metalworkers yet known. It occurred in a Connecticut factory that produces precision parts for the aerospace industry. The workers typically presented with systemic and respiratory problems (“sick fatigue,” myalgias, cough, dyspnea, wheezing, and chest tightness). They had variable findings on clinical tests, which complicated diagnosis. An HP diagnostic index was developed to help reduce the uncertainties in case identification.

Methods

Data from 16 biopsy‐confirmed cases and 14 non‐HP patients were compared, and the HP diagnostic index was derived using variables that best discriminated between the two groups. The index is based on (a) work‐related symptoms, (b) dry crackles on auscultation, (c) restrictive spirometry, (d) decreased diffusion capacity and/or increased A‐a oxygen gradient, (e) elevated erythrocyte sedimentation rate, (f) abnormal radiographic images, and (g) abnormal gallium scans. We then applied the HP diagnostic index and, for comparison, the “Kenosha epidemiological case criteria” (developed during a recent HP outbreak in an automobile factory) to our data set.

Results

The HP diagnostic index and the Kenosha criteria confirmed HP in overlapping sets of 36 and 34 patients, respectively, that were both in good agreement with the clinical diagnoses.

Conclusions

The HP diagnostic index relies less heavily on symptoms, subjective evaluations, and invasive tests than the Kenosha criteria, but both identified similar subsets of the 61 patients as having HP. The HP diagnostic index could provide a useful tool in future HP outbreaks, which are increasingly being recognized in metalworking facilities. Am. J. Ind. Med. 42:150–162, 2002. © 2002 Wiley‐Liss, Inc.
Association between bone lead concentration and blood pressure among young adults
Authors: Gerr Fredric , Letz Richard , Stokes Lynette , Chettle David , McNeill Fiona , Kaye Wendy
Published: September 2002

Background

Occupational and environmental exposure to lead has been examined for its effect on blood pressure (BP) in adults with varying results. The present analyses assessed the association between bone lead concentration and BP in early adult life in persons exposed during childhood.

Methods

Study participants included young adult members of two cohorts with different past histories of lead exposure. Lead exposure was assessed using noninvasive K‐X‐ray fluorescence spectroscopy to quantify bone lead concentration, an index of long‐term lead exposure superior to current blood lead concentration. Systolic and diastolic BP measurements were obtained using conventional clinical methods. Multiple linear regression models were constructed to allow for control of covariates of BP identified a priori.

Results

Analyses were performed on 508 participants. While controlling for potential confounders, systolic BP was 4.3 mm Hg greater among members of the highest of four bone lead concentration groups (> 10 μgPb/g bone) when compared with the lowest bone lead concentration group (< 1 μgPb/g bone; P = 0.004), and diastolic BP was 2.8 mm Hg greater among members of the highest bone lead concentration group when compared with the lowest bone lead concentration group (P = 0.03).

Conclusions

These results suggest that substantial lead exposure during childhood can increase BP during young adulthood. Am. J. Ind. Med. 42:98–106, 2002. © 2002 Wiley‐Liss, Inc.
Re: MTBE misclassified
Authors: Goldstein Bernard D. , Erdal Serap
Published: September 2002

Dr. Mehlman's commentary is a further reminder of the many problems caused by our nation's cavalier adoption of oxygenated fuels without adequate scientific consideration of environmental consequences. We disagree with Dr. Mehlman only to the extent that we are not fully convinced that MTBE is clearly a probable human carcinogen, and we would not be critical of the National Toxicology Program. The close vote of the NTP panel is similar to the close vote of the California Proposition 65 Science Advisory Board Panel Committee which on a tie vote is in keeping with that of IARC. However, we think the evidence of the potential for carcinogenecity is more than sufficient to preclude exposing over 100 million Americans to MTBE without first obtaining far more proof of safety.
RE: Mesothelioma and lung tumors attributable to asbestos among petroleum workers. Am. J. Ind. Med. 2000. 37:275–282. I. Reply to Tsai et al.'s letter to the editor and new evidence
Authors: Gennaro Valerio , Montanaro Fabio , Ceppi Marcello , Fontana Vincenzo , Perrotta Alessandra , Puntoni Riccardo , Finkelstein Murray M. , Silvano Stefania
Published: September 2002

We recently conducted a re‐analysis [Gennaro et al. 2000] of two independent studies among oil refineries workers: an Italian cohort study [Gennaro et al., 1994,1995] and a Canadian case‐control study [Finkelstein, 1996]. In the re‐analysis we reported that maintenance workers (MW) experienced an asbestos‐attributable risk (AR) of 96‐100% for mesothelioma; the same subgroup of workers showed an asbestos AR for lung cancer of 49.2 (95% Confidence Interval (CI) = 26.4‐72.4) in the Italian cohort study and an AR of 42.2 (95% CI=10.8‐82.6) in the Canadian study. White collar workers (WCW), likely unexposed to asbestos, were considered the internal referent population in the Italian cohort
study, while other workers were the comparison group in the Canadian study.
Assignment of work involving farm tractors to children on North American farms†
Authors: Marlenga Barbara , Pickett William , Berg Richard L.
Published: September 2002

Background

Children are at high risk for tractor‐related injury. The North American Guidelines for Children's Agricultural Tasks (NAGCAT) provide recommendations for the assignment of tractor work. This analysis describes tractor‐related jobs assigned to farm children and compares them to NAGCAT.

Methods

A descriptive analysis was conducted of baseline data collected by telephone interview during a randomized, controlled trial.

Results

The study population consisted of 1,138 children who worked on 498 North American farms. A total of 2,389 farm jobs were reported and 456 (19.1%) involved operation of farm tractors. Leading types of tractor jobs were identified. Modest, yet important, percentages of children were assigned tractor work before the minimum ages recommended by NAGCAT.

Conclusions

Children on farms are involved in tractor work at a young age and some are involved in jobs that they are unlikely to have the developmental abilities to perform. NAGCAT is a new parental resource that can be applied to these work situations. Am. J. Ind. Med. 40:15–22, 2001. © 2001 Wiley‐Liss, Inc.
Neuropsychological function in Gulf War veterans: relationships to self‐reported toxicant exposures
Authors: White Roberta F. , Proctor Susan P. , Heeren Timothy , Wolfe Jessica , Krengel Maxine , Vasterling Jennifer , Lindem Karen , Heaton Kristin J. , Sutker Patricia , Ozonoff David M.
Published: September 2002

Background

The present study was aimed at (1) exploring evidence of central nervous system (CNS) dysfunction among Gulf War (GW) veterans on neuropsychological tests and (2) examining whether performance on neuropsychological tests was related to specific neurotoxicant exposures experienced in the Gulf.

Methods

The GW‐deployed groups were selected using stratified random sampling methods from two distinct cohorts of GW veterans. A comparison group that had been called up for GW service but deployed to Germany rather than the Gulf also was examined. Neuropsychological function was assessed using a pre‐determined battery chosen to include tests known to be highly sensitive to the behavioral effects of the neurotoxicants thought to have been present in the Gulf.

Results

Self‐reported exposures were related to neuropsychological test performance controlling for post‐traumatic stress disorder, major depression, and other known covariates of neuropsychological test performance. Results showed that GW‐deployed veterans performed more poorly than the Germany‐deployed veterans on several specific neuropsychological tests, but after adjustment for multiple comparisons, only the differences in mood complaints remained significant. Within the GW‐deployed group, self‐reported exposure to chemical warfare agents was associated with poorer performance on cognitive tests involving specific functional domains.

Conclusions

Results provide evidence that there are subtle differences in CNS function among GW‐deployed veterans who report chemical warfare agent exposure while in the GW theater. Am. J. Ind. Med. 40:42–54, 2001. © 2001 Wiley‐Liss, Inc.
Respiratory function in active firefighters
Authors: Mustajbegovic Jadranka , Zuskin Eugenija , Schachter E. Neil , Kern Josipa , Vrcic‐Keglevic Mladenka , Heimer Stjepan , Vitale Ksenija , Nada Turcic
Published: September 2002

Background

Exposure to environmental pollution during firefighting may results in the development of respiratory disorders in firefighters.

Methods

The health effects of firefighting on respiratory function was investigated in a group of 128 active firefighters by recording respiratory symptoms and measuring lung function. In addition, 88 control workers, not exposed to known pollutants were studied for the prevalence of acute and chronic respiratory symptoms.

Results

Significantly higher prevalences of dyspnea, nasal catarrh, sinusitis, and hoarseness were recorded in firefighters compared to control workers (P < 0.01). One subject developed asthma symptoms following two intense firefighting episodes. A high prevalence of acute symptoms experienced during and after fire extinguishing was also documented among these firefighters. Eye and throat irritation as well as headache were prominent. A logistic regression analysis of chronic respiratory symptoms demonstrated that odds ratios were significant for both duration of work exposure and for smoking. Lung function testing demonstrated a decrease in FEF75 in relation to predicted suggesting obstructive changes in the smaller airways. A regression analysis of ventilatory capacity tests indicated a positive relationship of forced vital capacity with length of employment, 1 s forced expiratory volume as well as FEF50 were related to smoking, and FEF75 was related to both smoking and length of employment.

Conclusions

Our data suggest that firefighters are at risk for developing acute and chronic respiratory symptoms as well as obstructive airway changes. Am. J. Ind. Med. 40:55–62, 2001. © 2001 Wiley‐Liss, Inc.
Blood pressure, left ventricular mass, and lead exposure in battery manufacturing workers*†
Authors: Tepper Allison , Mueller Charles , Singal Mitchell , Sagar Kiran
Published: September 2002

Background

Although debate about the relationship between lead and blood pressure has focused on low environmental lead levels, industrial exposure remains a concern.

Methods

We measured blood pressure and left ventricular mass (LVM) in 108 battery manufacturing workers, and calculated cumulative and historic average measures of blood lead.

Results

Diastolic pressure increased with increasing lead levels, with a significant (P = 0.04) 5 mmHg difference in mean pressure between the highest and lowest cumulative exposure levels. Diastolic pressure increased with the log of cumulative lead (P = 0.06). Both hypertension (defined as currently medicated or systolic > 160 mmHg or diastolic > 95 mmHg) and LVM increased nonsignificantly with increasing lead exposure (P‐values ≥ 0.17 for hypertension and ≥ 0.20 for LVM).

Conclusions

We found a small effect of blood lead on diastolic blood pressure, particularly for a cumulative measure of exposure, but no convincing evidence of associations between lead and other blood‐pressure‐related outcomes. Am. J. Ind. Med. 40:63–72, 2001. Published 2001 Wiley‐Liss, Inc.
Occupational cancer genetics: infrequent ras oncogenes point mutations in lung cancer samples from chromate workers
Authors: Ewis Ashraf A. , Kondo Kazuya , Lee Juwon , Tsuyuguchi Masaru , Hashimoto Masato , Yokose Tomoyuki , Mukai Kiyoshi , Kodama Tetsurou , Shinka Toshikatsu , Monden Yasumasa , Nakahori Yutaka
Published: September 2002

Background

Chromium carcinogenicity and mutagenicity are no longer disputed. However, although chromium has various genetic effects that induce cancer, its mechanism of inducing lung cancer in humans is still not fully understood. p53, a tumor suppressor gene, was found to be infrequently mutated in samples of lung cancer in workers with long occupational exposure to chromium, suggesting other cancer‐related genes to be targeted in such tumors.

Methods

To assess the contribution of the ras oncogenes in the pathogenesis of chromate‐related lung cancer, we studied point mutations at the critical positions of codons 12, 13, and 61 of the Ha‐ras and Ki‐ras oncogenes in 38 lung cancer samples derived from Japanese patients who worked in the chromate industry for long periods. We used both radioactive isotope and non‐radioisotope PCR‐SSCP techniques.

Results

The results of this study demonstrated that activation of ras genes due to point mutations in chromate‐related lung cancer is a rare event.

Conclusions

Ras oncogenes activated by point mutations do not have a major role in the process of tumorigenesis of chromate‐related lung cancer. Am. J. Ind. Med. 40:92–97, 2001. © 2001 Wiley‐Liss, Inc.