bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Fluorinated Molecules (Semiochemicals and Enzyme Substrate Analogues) on the Insect Communication System
Authors: Pesenti Cristina , Viani Fiorenza
Published: April 2004

Can the introduction of fluorine atoms affect the bioactivity of natural semiochemicals? Can fluorine contribute in the creation of specific enzyme inhibitors to interrupt or disrupt the insect communication system? The first step for the bioactivity of a molecule is interaction with the biological sensor. Hydrogen and fluorine are almost bioisosteric and the receptor site of the enzyme can still recognize and accept the fluoro analogue of its natural substrate. However, the peculiar electronegativity of the fluorine atom can affect the binding, absorption, and transport of the molecule. The differences in the molecule's electronic properties can lead to differences in the chemical interactions between the receptor and the fluorinated substrate. Fluorine introduction can modify the metabolic stability and pathway of the semiochemicals in many different ways. Fluorinated analogues can show synergism, inhibition, or hyperagonism effects on insect behaviors, that is, the activity of the nonfluorinated parent compounds can be mimicked, lost, or increased. In any case, the fluorinated molecules can interact with the bioreceptors in a new and disrupting way. The semiochemicals are olfactory substances: fluorine can affect their volatility or smell. Production of semiochemicals from exogenous substances, perception at antennal receptors, and processing of biological responses are the main steps of communication among insects. In the production step, the fluorinated molecules can interact with enzymes that catalyze the biosynthesis of the natural pheromones. In the perception step, fluorinated semiochemicals can interact with the olfactory receptor cells; this often leads to totally unpredictable behaviors. Fluorinated molecules have been developed as probes to elucidate the complex chemorecognition processes of insects. Many of these molecules have been tested to find highly effective behavior‐modifying chemicals. New analogues have been synthesized to investigate the metabolic pathway of a pheromone molecule and many of them are promising disrupting agents. Despite such titanic research efforts, the results have often been random, rational trends in the induced behaviors have sometimes been impossible to find, and practical applications of the fluorinated semiochemicals are still uncertain.
Cover Picture: Enzymatic Fluorination in Streptomyces cattleya Takes Place with an Inversion of Configuration Consistent with an SN2 Reaction Mechanism (ChemBioChem 5/2004)
Authors: Cadicamo Cosimo D. , Courtieu Jacques , Deng Hai , Meddour Abdelkrim , O'Hagan David
Published: April 2004

The cover picture shows a mechanism of the fluorination enzyme from Streptomyces cattleya whereby a fluoride ion mediates a nucleophilic substitution reaction on S‐adenosyl‐L‐methionine (SAM). This conclusion is drawn after exploring the enzyme reaction with deuterium‐labelled (5′S)‐[5′‐2H1]‐SAM to generate a product with a chiral fluoromethyl group. Enantiomeric assay for the chiral fluoromethyl group by 2H NMR in a chiral liquid‐crystalline medium (the Courtieu method) allowed evaluation of the absolute configuration of the resultant chiral fluoromethyl group. More details on this study by A. Meddour, D. O'Hagan et al. are described on p. 685 ff.
DECHEMA‐Weiterbildungskurs „Mikroverfahrenstechnik”︁
Authors: Stief T. , Langer O.‐U.
Published: April 2004

No abstracts.
Elektrochemische Mikrodurchflussanordnung für Standardexperimente im Studium
Authors: Günther M. , Köhler J. M.
Published: April 2004

No abstracts.
Flüssig/Flüssig‐Dispergierung im Interdigital‐Mikromischer
Authors: Pennemann H. , Löb P. , Hessel V. , Weise F. , Hardt S.
Published: April 2004

No abstracts.
Numbering up von Mikroreaktoren: Ein neues Flüssigkeitsverteilsystem
Authors: Schenk R. , Hessel V. , Hofmann C. , Kiss J. , Löwe H. , Schönfeld F. , Ziogas A.
Published: April 2004

No abstracts.
Chlamydia trachomatis and invasive cervical cancer: A pooled analysis of the IARC multicentric case‐control study
Authors: Smith Jennifer S. , Bosetti Cristina , Muñoz Nubia , Herrero Rolando , Bosch F. Xavier , Eluf‐Neto José , Meijer Chris J.L.M. , van den Brule Adriaan J.C. , Franceschi Silvia , Peeling Rosanna W.
Published: April 2004

To determine whether Chlamydia trachomatis infection is consistently associated with an increased risk of invasive cervical carcinoma (ICC) after accounting for the strong effect of human papillomavirus (HPV) infection, a case‐control study of 1,238 cases of ICC and 1,100 control women from 7 countries was carried out (hospital‐based studies in Thailand, the Philippines, Morocco, Peru, Brazil and population‐based studies in Colombia and Spain, all coordinated by the International Agency for Research on Cancer, Lyon, France). C. trachomatis serum antibody detection was made by means of a microfluorescence assay. Among HPV DNA‐positive cases and controls, the risk of squamous cell ICC was elevated in C. trachomatis seropositive women (OR = 1.8; 95% CI = 1.2–2.7) after adjustment for age, center, oral contraceptive use, history of Pap smears, number of full‐term pregnancies and herpes simplex virus 2 seropositivity. The effect of C. trachomatis seropositivity on squamous cell ICC risk increased with increasing C. trachomatis antibody titers and was higher in women under 55 years of age. C. trachomatis antibodies were not associated with adeno‐ or adenosquamous cell carcinoma (OR = 1.0; 95% CI = 0.53–1.9) in HPV DNA‐positive women. An association of C. trachomatis with squamous cell ICC was found among all cases and control women with or without adjustment for HPV. © 2004 Wiley‐Liss, Inc.
Temporal Variations in Fine Sand Assemblages in the North Aegean Sea (Eastern Mediterranean)
Authors: Kourelea Evdokia , Vafidis Dimitrios , Chintiroglou Chariton‐Charles , Trontsios Georgios , Chicharo Louis
Published: April 2004

Two sites were selected in the North Aegean Sea for the study of shallow fine sand assemblages, which are poorly known in the Eastern Mediterranean. The biomonitoring of these sites can provide useful information on the impact of human activities on the macrofaunal and meiofaunal composition of these assemblages. In order to examine this impact, sampling took place in five different periods between 2000 and 2001. The qualitative and quantitative compositions of the communities at the two sites showed certain differences, mostly between the sites and the year of sampling rather than between sampling periods, which would be the expected outcome. The communities seem to be affected by a combination of the human activities with the particular hydrodynamics of the studied sites.
Reproductive toxic effect of bisphenol A dimethacrylate in mice
Authors: Darmani Homa , Al‐Hiyasat Ahmad S.
Published: April 2004

The current study evaluated the effect of bisphenol A dimethacrylate (Bis‐DMA) on mouse fertility. Adult male and female mice were exposed to intragastric Bis‐DMA (0, 5, 25, and 100 μg/kg) daily for 28 days and then mated with sexually mature untreated mice and after mating fertility was assessed. Females mated by males that had been exposed to Bis‐DMA had significant reductions in pregnancy rates and significant increases in the total number of resorptions out of the total number of implantations. Bis‐DMA exposed males had significant reductions in body weights and relative testes weights and significant increases in seminal vesicle and preputial gland weights. Testicular and epididymal sperm counts as well as the efficiency of sperm production were also significantly reduced in these groups. Female mice exposed to Bis‐DMA showed significant reductions in pregnancy rates, number of implantation sites, number of viable fetuses, and total number of resorptions out of the total number of implantations. Significant reductions in the body weights were observed at all doses, and significant increases were found in the relative weights of the ovaries and the uterus. The results suggest that Bis‐DMA has adverse effects on the fertility and reproductive systems of male and female mice. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 637–643, 2004
Surface modification of titanium implant by microarc oxidation and hydrothermal treatment
Authors: Huang Ping , Zhang Yong , Xu Kewei , Han Yong
Published: April 2004

Surface modification of titanium implant is processed by microarc oxidation and hydrothermal treatment. A porous surface with a biologically active bone‐like apatite layer was formed. The apatite layer consists of very fine crystals and high crystallinity and is integrated with the titanium alloy substrate with a graded structure without a distinct interface. Such a bioactive layer is expected not only to enhance the bony ingrowth into the porous structure, but also to improve the interlocking between implant and bone. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 187–190, 2004
Prenatal sonographic diagnosis of acrania associated with amniotic bands
Authors: Chen Chih‐Ping , Chang Tung‐Yao , Lin Yi‐Hui , Wang Wayseen
Published: April 2004

We describe the prenatal sonographic findings in 2 cases of amniotic band sequence‐related acrania. In the first case, sonography demonstrated acrania, asymmetric facial clefts, and digital fusion on the hands and feet. In the second case, sonography demonstrated acrania and amniotic bands adhering to the brain, face, and body. This report highlights the importance of a careful search for amniotic bands and a detailed survey of the fetus' face, digits, and body in the sonographic evaluation of fetal acrania. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:256–260, 2004; Published online in Wiley InterScience (www. interscience.wiley.com). DOI: 10.1002/jcu.20021
Young adult survivors of childhood acute lymphoblastic leukemia: Spontaneous GH secretion in relation to CNS radiation
Authors: Jarfelt M. , Bjarnason R. , Lannering B.
Published: April 2004

Background

Young adults who are long‐term survivors of acute lymphoblastic leukaemia (ALL) in early childhood usually do well and do not have to go to regular medical checkups. Many of these survivors did receive prophylactic cranial radiotherapy during their oncological treatment. The effect of cranial irradiation on the hypothalamus is considered to be progressive. Therefore, late effects, such as reduced growth hormone (GH) secretion, may remain undetected until adulthood.

Procedure

Records from all patients treated for ALL before the onset of puberty in the region of West Sweden, between 1 January 1973 and 31 December 1985 were included, provided they were in first remission with a minimum follow‐up time of 15 years, and a minimum age of 20. These criteria were met by 47 young adults aged 20–32 years, of whom 35 agreed to participate. We studied spontaneous GH secretion over 24 hr, IGF‐I and IGFBP‐3, final height and BMI. The patients had been treated according to three consecutive Swedish childhood leukaemia group protocols. The median follow‐up time was 20 years, and 19 of the patients had been treated with cranial irradiation (CRT+), 16 had not (CRT−).

Results

CRT+ patients had significantly lower maximal peaks of GH than CRT− patients. Fifty percent of the CRT+ patients had a GHmax below the cut‐off level (3.3 μg/l), for GH treatment. CRT− patients all had GHmax levels considered within the normal range. Final height of all the patients, except one CRT+ women, was in the range of expected midparental height, the median loss in final height in the CRT+ patients was 0.8 standard deviation (SD). No patient in this study was obese by definition (BMI <30 kg/m2). IGF‐I and IGFBP‐3 concentrations did not correlate to variations in spontaneous GH secretion in these patients.

Conclusions

In spite of the little effect on final height, we found impaired spontaneous GH secretion in 79% of young adults 20–32 years of age, and GH deficiency (GHD) in 47% after low‐dose cranial irradiation in early childhood. The consequences of this low‐GH secretion need to be investigated. Pediatr Blood Cancer 2004;42:582–588. © 2004 Wiley‐Liss, Inc.
Flow modeling and simulation for vacuum assisted resin transfer molding process with the equivalent permeability method
Authors: Chen Renliang , Dong Chensong , Liang Zhiyong , Zhang Chuck , Wang Ben
Published: April 2004

Vacuum assisted resin transfer molding (VARTM) offers numerous advantages over traditional resin transfer molding, such as lower tooling costs, shorter mold filling time and better scalability for large structures. In the VARTM process, complete filling of the mold with adequate wet‐out of the fibrous preform has a critical impact on the process efficiency and product quality. Simulation is a powerful tool for understanding the resin flow in the VARTM process. However, conventional three‐dimensional Control Volume/Finite Element Method (CV/FEM) based simulation models often require extensive computations, and their application to process modeling of large part fabrication is limited. This paper introduces a new approach to model the flow in the VARTM process based on the concept of equivalent permeability to significantly reduce computation time for VARTM flow simulation of large parts. The equivalent permeability model of high permeable medium (HPM) proposed in the study can significantly increase convergence efficiency of simulation by properly adjusting the aspect ratio of HPM elements. The equivalent permeability model of flow channel can simplify the computational model of the CV/FEM simulation for VARTM processes. This new modeling technique was validated by the results from conventional 3D computational methods and experiments. The model was further validated with a case study of an automobile hood component fabrication. The flow simulation results of the equivalent permeability models were in agreement with those from experiments. The results indicate that the computational time required by this new approach was greatly reduced compared to that by the conventional 3D CV/FEM simulation model, while maintaining the accuracy, of filling time and flow pattern. This approach makes the flow simulation of large VARTM parts with 3D CV/FEM method computationally feasible and may help broaden the application base of the process simulation. Polym. Compos. 25:146–164, 2004. © 2004 Society of Plastics Engineers.
Thermally conductive carbon filled nylon 6,6
Authors: Heiser Jessica A. , King Julia A.
Published: April 2004

Increasing the thermal conductivity of typically insulating polymers, such as nylon 6,6, opens new markets. A thermally conductive resin can be used for heat sink applications. This research focused on performing compounding runs followed by injection molding and through‐plane thermal conductivity testing of carbon filled nylon 6,6 based resins. The three carbon fillers investigated included an electrically conductive carbon black, synthetic graphite particles, and a surface treated polyacrylonitrile (PAN) based carbon fiber. Conductive resins were produced and tested that contained varying amounts of these single carbon fillers. In addition, combinations of fillers were investigated by conducting a full 23 factorial design and a complete replicate. The objective of this paper was to determine the effects and interactions of each filler on the thermal conductivity of the resins. Synthetic graphite particles caused the largest increase in composite thermal conductivity. In addition, all the single fillers and combinations of fillers caused a statistically significant (at the 95% confidence level) increase in composite thermal conductivity. Polym. Compos. 25:186–193, 2004. © 2004 Society of Plastics Engineers.
A potential bias in safety evaluation during open‐label extensions of randomized clinical trials
Authors: Rothman Kenneth J.
Published: April 2004

Purpose

To describe a bias that can occur in the analysis of data from certain randomized trials.

Methods and Results

Although randomized trials are effective at preventing confounding, a potentially strong confounding can arise in certain therapeutic drug trials in which follow‐up is extended in an open‐label phase that allows switching treatments. Many trials implement eligibility screening that excludes those at high risk of morbidity and mortality. In these trials, disease rates and death rates for the study population can rise rapidly during follow‐up as the effect of screening wanes. During the open‐label follow‐up, a preponderance of patients may switch to the new therapy. If so, then any evaluation of the new therapy that includes follow‐up from the open‐label phase, as is often the case for safety evaluations, will be confounded. The confounding arises because the person‐time experience of those on the new treatment will be more heavily weighted with the open‐label phase experience, during which morbidity and mortality rates may be much greater than in the initial phase of follow‐up. This confounding may be strong and will be in the direction of making the new treatment look worse, provided that the net switching is toward the new treatment during the open‐label phase.

Conclusions

The confounding described here is not prevented by randomization because it develops in a non‐randomized add‐on analysis to the trial. The bias can be removed, however, by controlling for time since randomization in the analysis of the data. Copyright © 2004 John Wiley & Sons, Ltd.
Mechanism of preparing monodisperse poly(acrylamide/methacrylic acid) microspheres in ethanol. I
Authors: Ni Henmei , Kawaguchi Haruma
Published: April 2004

The precipitation polymerization of acrylamide/methacrylic acid (AAm/MAA) in ethanol (EtOH) was thoroughly investigated from detecting the homogeneity of the initial solution prior to polymerizations to the final products of the polymerizations. Dynamic light scattering and scanning electron microscopy were employed for the investigations. The solutions of AAm and AAm/acrylic acid (AAm/AA) were homogeneous. However, the solutions of AAm/MAA, AAm/poly(MAA) (PMAA), and AAm/poly(AA) (PAA) were not homogeneous as they are usually considered to be: entities with size distributions of around 150, 40, and 17 nm, respectively, were detected at the polymerization temperature of 60 °C. Accordingly, analogous to the entities that are similar to the structure of micelles formed in the solutions of AAm/PMAA and AAm/PAA because of polymer–AAm interactions, it was suggested that the complexes of AAm/MAA stemming from the molecular interactions, particularly the (lypo‐) hydrophobic interaction, aggregated to form minimonomer droplets at 60 °C. The monodisperse microspheres were prepared only in the AAm/MAA‐EtOH systems, whereas the microspheres were not prepared in the homogeneous AAm‐EtOH systems despite the precipitation of PAAm. The results obtained from various polymerizations showed that the microspheres originated from the polymerization within the minimonomer droplets. A new mechanism was established that describes the processes for the formation of all products possibly generated in the AAm‐MAA‐EtOH polymerization system. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2823–2832, 2004
Atom transfer radical polymerization of methyl methacrylate by copper(I)‐pyridine‐2‐carboximidate catalysts
Authors: Lee Do W. , Seo Eun Y. , Cho Sung I. , Yi Chae S.
Published: April 2004

Pyridine‐2‐carboximidates [methyl (1a), ethyl (1b), isopropyl (1c), cyclopentyl (1d), cyclohexyl (1e), n‐octyl (1f), and benzyl (1g)] were prepared from the reaction of 2‐cyanopyridine with the corresponding alcohols. Cyclopentyl‐substituted 1d was found to be a highly effective ligand for copper‐catalyzed atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA). For example, the observed rate constant for a CuBr/1d catalytic system was found to be nearly twice as high as the cyclohexyl‐substituted CuBr/1e catalytic system [kobs = (1.19 vs 0.56) × 10−4 s−1). The effects of the solvents, temperature, catalyst/initiator, and solvent/monomer ratio on the ATRP of MMA were studied systematically for the CuBr/1d catalytic system. The optimum condition for the ATRP of MMA was found to be a 1:2:1:400 [CuBr]o/[1d]o/[ethyl 2‐bromoisobutyrate]o/[MMA]o ratio at 60 °C in veratrole solution, which yielded well‐defined poly(MMA) with a narrow molecular weight distribution of 1.14. The catalytically active copper complex 2d was isolated from the reaction of CuBr with 1d. Narrow molecular weight distributions as low as 1.06 were achieved for the CuBr/1d catalytic system by employing 10% of the deactivator CuBr2. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2747–2755, 2004
A Constant‐Density Gurney Approach to the Cylinder Test
Authors: Reaugh John E. , Souers P. Clark
Published: April 2004

The previous analysis of the Cylinder test required the treatment of different wall thicknesses and wall materials separately. To fix this, the Gurney analysis is used, but this results in low values for full‐wall standard, ideal explosives relative to CHEETAH analyses. A new constant metal‐density model is suggested, which takes account of the thinning metal wall as the cylinder expands. With this model, the inner radius of the metal cylinder moves faster than the measured outer radius. Additional small corrections occur in all cylinders because of energy trapped in the copper walls. Also, the half‐wall cylinders have a small correction because the relative volumes of the gas products are smaller at a given outside wall displacement. The Fabry‐Perot and streak camera measurements are compared. The Fabry method is shown to equate to the constant density model.
Development and large scale benchmark testing of the PROSPECTOR_3 threading algorithm
Authors: Skolnick Jeffrey , Kihara Daisuke , Zhang Yang
Published: April 2004

This article describes the PROSPECTOR_3 threading algorithm, which combines various scoring functions designed to match structurally related target/template pairs. Each variant described was found to have a Z‐score above which most identified templates have good structural (threading) alignments, Zstruct (Zgood). ‘Easy’ targets with accurate threading alignments are identified as single templates with Z > Zgood or two templates, each with Z > Zstruct, having a good consensus structure in mutually aligned regions. ‘Medium’ targets have a pair of templates lacking a consensus structure, or a single template for which Zstruct < Z < Zgood. PROSPECTOR_3 was applied to a comprehensive Protein Data Bank (PDB) benchmark composed of 1491 single domain proteins, 41–200 residues long and no more than 30% identical to any threading template. Of the proteins, 878 were found to be easy targets, with 761 having a root mean square deviation (RMSD) from native of less than 6.5 Å. The average contact prediction accuracy was 46%, and on average 17.6 residue continuous fragments were predicted with RMSD values of 2.0 Å. There were 606 medium targets identified, 87% (31%) of which had good structural (threading) alignments. On average, 9.1 residue, continuous fragments with RMSD of 2.5 Å were predicted. Combining easy and medium sets, 63% (91%) of the targets had good threading (structural) alignments compared to native; the average target/template sequence identity was 22%. Only nine targets lacked matched templates. Moreover, PROSPECTOR_3 consistently outperforms PSIBLAST. Similar results were predicted for open reading frames (ORFS) ≤200 residues in the M. genitalium, E. coli and S. cerevisiae genomes. Thus, progress has been made in identification of weakly homologous/analogous proteins, with very high alignment coverage, both in a comprehensive PDB benchmark as well as in genomes. Proteins 2004;55:000–000. © 2004 Wiley‐Liss, Inc.
Negative ion electrospray ionization mass spectral study of dicarboxylic acids in the presence of halide ions
Authors: Kumar M. Ravi , Prabhakar S. , Kumar M. Kiran , Reddy T. Jagadeshwar , Vairamani M.
Published: April 2004

The negative ion electrospray ionization (ESI) mass spectra of a series of dicarboxylic acids, a pair of isomeric (cis/trans) dicarboxylic acids and two pairs of isomeric (positional) substituted benzoic acids, including a pair of hydroxybenzoic acids, were recorded in the presence of halide ions (F−, Cl−, Br− and I−). The ESI mass spectra contained [MH]− and [M+X]− ions, and formation of these ions is found to be characteristic of both the analyte and the halide ion used. The analytes showed a greater tendency to form adduct ions with Cl− under ESI conditions compared with the other halide ions used. The isomeric compounds yielded distinct spectra by which the isomers could be easily distinguished. The collision‐induced dissociation mass spectra of [M+X]− ions reflected the gas‐phase basicities of both the halide ion and [MH]− ion of the analyte. However, the relative ordering of gas‐phase basicities of all analyte [MH]− and halide ions could not account for the dominance of chloride ion adducts in ESI mass spectra of the analytes mixed with equimolar quantities of the four halides. Copyright © 2004 John Wiley & Sons, Ltd.
Pyoderma Gangrenosum with a Contiguous Erosion of the Distal Ulna
Authors: Hayes Robert C. , Curtis Anne
Published: April 2004

Background

Pyoderma gangrenosum (PG) has been described in association with sterile neutrophilic infiltration of several organ systems, including the skeleton. The most frequent cause of bony disease in PG has been chronic, recurrent, multifocal osteomyelitis, a sterile inflammatory disease of children and young adults mimicking infectious osteomyelitis. Bony erosions have been only rarely described in direct contiguity to a PG ulcer.

Objective

We report a 53-year-old woman with recurrent PG who developed an erosion of the distal ulna adjacent to a PG ulcer. The patient responded to high-dose prednisone, and a repeat radiograph of the wrist four months later was normal.

Conclusion

This case demonstrates another example of cortical osteolysis directly adjacent to a PG ulcer in which the bony changes may be neutrophil-induced.
Co‐localization of CD3 and prion protein in Jurkat lymphocytes after hypothermal stimulation
Authors: Wurm Susanne , Paar Christian , Sonnleitner Alois , Sonnleitner Max , Höglinger Otmar , Romanin Christoph , Wechselberger Christian
Published: April 2004

While long‐term effects of temperature treatment in respect of, e.g., gene‐expression and cellular function have already been studied in some detail, nothing is known on the physiological responses of lymphocytes during short‐term hypothermal shifts. In this report, we characterized the effects of such a stimulation using the human lymphocyte cell line Jurkat E6.1 and present evidence that warming from 4 to 37 °C for only 2 min is sufficient to cause co‐localization of CD3, prion protein and the lipid‐raft ganglioside GM1 paralleling lymphocyte activation as observed by Ca2+ mobilization and mitogen‐activated protein kinase‐phosphorylation.
Fission yeast Skp1 is required for spindle morphology and nuclear membrane segregation at anaphase
Authors: Lehmann Anna , Toda Takashi
Published: April 2004

Skp1 is a core component of the kp1‐ullin‐1‐‐box ubiquitin ligase. Here, we show a novel role for fission yeast Skp1 in mitotic progression. Temperature‐sensitive skp1‐A7 mutants enter mitosis, but fail to execute anaphase. Time‐lapse imaging shows that spindles in this mutant form intranuclear arch‐like structures, which eventually collapse abruptly. The two spindle poles are also seen to move backward to the cell centre rather than towards the cell ends. These abnormal phenotypes appear to stem from defects in nuclear membrane segregation. Our results show that Skp1 is required for coordinated structural alterations of mitotic spindles and nuclear membranes.
The farnesoid X receptor induces very low density lipoprotein receptor gene expression
Authors: Sirvent Audrey , Claudel Thierry , Martin Geneviève , Brozek John , Kosykh Vladimir , Darteil Raphaël , Hum Dean W. , Fruchart Jean-Charles , Staels Bart
Published: April 2004

The farnesoid X receptor (FXR) is a nuclear receptor activated by bile acids (BAs). In response to ligand‐binding, FXR regulates many genes involved in BA, lipid, and lipoprotein metabolism. To identify new FXR target genes, microarray technology was used to profile total RNA extracted from HepG2 cells treated with the natural FXR agonist chenodeoxycholic acid (CDCA). Interestingly, a significant increase of transcript level of the very low density lipoprotein receptor (VLDLR) was observed. Our data, resulting from selective FXR activation, FXR RNA silencing and FXR‐deficient mice, clearly demonstrate that BAs up‐regulate VLDLR transcript levels via a FXR‐dependent mechanism in vitro in human and in vivo in mouse liver cells.
Rb–Sr systematics of Holocene pelitic sediments and their bearing on whole-rock dating
Authors: CORDANI UMBERTO G. , MIZUSAKI ANA M. , KAWASHITA KOJI , THOMAZ-FILHO ANTONIO
Published: April 2004

In many cases, when dealing with argillaceous fine-grained sedimentary rocks, the isotopic ages obtained from Rb–Sr whole-rock isochron calculations are of geological significance, despite the fact that the initial conditions of Sr isotopic homogenization are not fulfilled. To explain this, a mechanical mixing during deposition has been suggested, leading to an aggregate of mixed material with fairly uniform 87Sr/86Sr values, whatever Rb/Sr ratio is found in the analysed samples. This investigation of the behaviour of Rb and Sr during sedimentation and early diagenesis, involves study of more than 60 samples of fine-grained recent sediments from selected coastal localities of Brazil. The results indicate that pelitic samples from some recent to present-day transitional or shallow marine environments, such as the Jacarepaguá tidal flat and the Amazonas River mouth, where halmirolysis could have occurred, may produce nearly horizontal best-fit lines in a Rb–Sr isochron diagram. Moreover, the initial isotopic 87Sr/86Sr ratios appear to be well above 0.710. In open marine environments, such as the Campos Basin, where sampling was spread over more than 100 metres, exchanges between the argillaceous sediments and seawater potentially happen at low temperature, inducing a reduction of the 87Sr/86Sr isotopic composition of the sediments to nearly 0.710. An almost horizontal best-fit line is produced for the entire stratigraphic section, independent of the sedimentation age. We believe that in similar environments such ‘zero age isochrons’ are maintained for some time, testifying to exchanges between the sediment and the interstitial fluids, before the onset of burial diagenesis. The above described studies on fine-grained and recent argillaceous sediments seem to confirm the production of horizontal best-fit lines in isochron diagrams, justifying the application of the Rb–Sr whole-rock method to pelitic sedimentary rocks. The nature of the material is critical. The pelitic sediments to be analysed should contain only very limited amounts of coarse clastic material (especially feldspars and mica fragments) and consist mainly of fine clay minerals in which smectites, illite and mixed layers illite–smectite largely predominate.
The conquest of Khu¯zista¯n: a historiographical reassessment
Authors: ROBINSON CHASE F.
Published: April 2004

The ‘appendix’ to a mid- to late seventh-century East Syriac history includes a detailed account of the conquest of Khu¯zista¯n by Muslim armies between c. 635 and 642. This article translates this section of the ‘appendix’ (along with another dealing with the conquest of Egypt), subjects it to detailed analysis and criticism, and compares it with Arabic accounts of the conquest of Khu¯zista¯n that survive in the much later historical and legal traditions. The results of this exercise—using an early and local source to control the Islamic tradition—is in some measure mixed, but some striking agreement suggests that the transmission of conquest history in early Islam was not as discontinuous as has been previously argued.
Live performance interaction for humans and machines in the early twenty-first century: one composer's aesthetics for composition and performance practice
Authors: BELET BRIAN
Published: April 2004

Technology influences all art, and therefore all music,
including composition, performance and listening. It
always has, and it always will. For example, technical
developments in materials, mechanics and manufacturing
were important factors that permitted the piano
to supersede the harpsichord as the primary concert
Western keyboard instrument by about 1800. And
with each new technical development new performance
issues have been introduced. Piano performance
technique is quite different from harpsichord
technique, and composers responded to these differences
with new music ideas and gestures. The multiple
relationships between technology and composer and
performer are dynamic and of paramount importance
to each party. And a true consideration of any aspect
of music requires that all three areas be examined. This
has always been a part of music, and so these relationships
are inherently important within computer music.
The difference is that electronic technology has caused
a fundamental change for all aspects of music, a difference
that is as pivotal in the history of Western music
as was the shift from oral to written preservation of
music over a thousand years ago, and then also the
accessibility provided by printed music five hundred
years ago. In computer music, all parties are always
acutely aware of the presence and influence of
machine technology in both the visual and audible
realms.
Wer verdient Hilfe?
Authors: Volland Cordelia , Ulich Dieter , Fischer Andrea
Published: April 2004

Zusammenfassung. In der vorliegenden Studie wurde der Einfluss von fünf Empfängermerkmalen auf die prosozialen Handlungsentscheidungen von vier- bis achtjährigen Kindern untersucht. Dazu wurden in einem Experiment die folgenden fünf Empfängermerkmale (unabhängige Variable) systematisch variiert: Verantwortung für eigenes Unglück, Vertrautheit, Lebensalter, Reziprozität und Schadensgröße. Insgesamt 277 Kinder übernahmen in fünf Puppenspiel-Szenen die Rolle des Protagonisten, der sich jeweils entscheiden mußte (abhängige Variable), welchem von zwei potenziellen Empfängern mit jeweils unterschiedlicher Merkmalsausprägung er helfen wollte. Die vier- bis achtjährigen Kinder bevorzugten bei ihren Entscheidungen überzufällig oft denjenigen Empfänger, der keine Verantwortung am eigenen Unglück hatte, der vertrauter war, der jünger war, der ihnen auch schon einmal geholfen hatte und der den größeren Schaden erlitten hatte. Mit steigendem Alter der Kinder nahm der Einfluss der Rezipientenmerkmale zu. Als Fazit ergibt sich sowohl ein eindeutiger Einfluss bestimmter Rezipientenmerkmale auf die prosozialen Handlungsentscheidungen von Kindern wie auch ein Entwicklungstrend in Richtung einer stärkeren Differenzierung zwischen potenziellen Rezipienten von Hilfe.
Student Research Award 1998: Clinimetric evaluation of the Sinonasal Outcome Test‐16
Authors: Anderson Eric R. , Murphy Michael P. , Weymuller Ernest A.
Published: April 2004

This study describes the reliability, validity, and responsiveness of the Sinonasal Outcome Test‐16 (SNOT‐16), a rhinosinusitis‐specific health‐related quality‐of‐life instrument, in the University of Washington Department of Otolaryngology‐Head and Neck Surgery patient Population. The SNOT‐16 was completed by 47, 24, and 22 patients at weeks 0, 6, and 12, respectively. In addition, all 47 patients completed the Short‐form 36‐item Health Survey (SF‐36) at week 0. Furthermore, an additional cohort of patients from the otology clinic who denied symptoms of rhinosinusitis or previous physician diagnoses of rhinosinusitis were asked to complete the SNOT‐16. These scores were subsequently used to determine discriminant validity of the instrument. Cronbach's alpha was 0.89, indicating a high degree of homogeneity of the test items. The SNOT‐16 demonstrated excellent discriminant validity, and mean total SNOT‐16 scores were significantly correlated with patient‐reported overall health, overall bother, and 7 of the 8 SF‐36 subscales. The standardized response mean calculated between weeks 0 and 6 was 0.69, indicating moderate sensitivity to change. We conclude that the SNOT‐16 is a reliable, valid, and responsive instrument for measuring rhinosinusitis‐specific health‐related quality of life.
Student Research Award 1998: Cytokine‐mediated bone resorption is cytochrome P‐450 dependent
Authors: Young Nwanmegha , Chole Richard
Published: April 2004

Localized bone loss leads to much of the morbidity of chronic otitis media. Although the cellular events of bone remodeling have been well established, their regulation remains Poorly understood. Various cytokines, including tumor necrosis factor‐α, interleukin‐1β, and interferon‐γ, used alone and in combination, are Powerful inducers of bone resorption. One of the modulators of cytokine‐induced bone resorption is nitric oxide (NO), a product of the action of NO synthase (NOS) on L‐arginine to form NO. Cytochrome P‐450, an enzyme that is similar to NOS both structurally and functionally, may also have a role in NO production in various cellular systems. The goal of this study was to elucidate a Possible role of cytochrome P‐450 in bone. In this study cytokine‐induced bone resorption was blocked with cimetidine and clotrimazole, which are selective inhibitors of the cytochrome P‐450 IIIA family and 7‐ethoxyresorufin, a nonspecific cytochrome P‐450 inhibitor. A concomitant reduction of NO was also observed. This effect may be explained by cytochrome P‐450 being a preferred alternative pathway or providing an essential cofactor to NOS in bone.
Clinical Care Pathways: Decreasing Resource Utilization in head and Neck Surgical Patients
Authors: Husbands Julian M. , Weber Randal S. , Karpati Ronit L. , Weinstein Gregory S. , Chalian Ara A. , Goldberg Andrew N. , Thaler Erica R. , Wolf Patricia F.
Published: April 2004

In this era of decreasing reimbursement, health systems have been forced to become more efficient and decrease resource utilization to remain financially viable. One of the methods of internal cost control has been the use of clinical pathways. Given the complexity of treatment of head and neck cancer patients, clinical pathways can help to standardize decision making and introduce uniformity in resource utilization. The objective of this study is to compare resource utilization and outcomes before and after implementation of a clinical pathway for head and neck surgical patients. We observed significant decreases in hospital costs as well as shorter lengths of stay after pathway implementation. It is our belief that a uniform management tool is beneficial in this complex disease.
On the symmetry of cylindrical implosions driven by a rotating beam of fast ions
Authors: Basko M. M. , Schlegel T. , Maruhn J.
Published: April 2004

Cylindrical implosions driven by intense beams of heavy ions are one of the promising ways to create high energy density states in matter. To ensure the needed azimuthal symmetry of the beam energy deposition, it was proposed [Sharkov et al., Nucl. Instrum. Methods Phys. Res. A 464, 1 (2001)] to rotate the ion beam around the target axis. Combining analytical calculations with two-dimensional hydrodynamic simulations, a lower limit is established on the frequency ν of the beam rotation dictated by the target hydrodynamics. This limit is shown to be directly proportional to the desired radial convergence ratio Cr for stepwise beam power profiles, and to Cr1/2 for smooth pulses. With a smooth pulse, 6–10 beam revolutions per pulse should be sufficient to reach Cr≃30, while a stepwise pulse requires ≃100 revolutions. Also, the upper bound on the asymmetry of the elliptical focal spot of a rotating ion beam is calculated.
Magnetohydrodynamic simulation of the inverse-pinch plasma discharge
Authors: Esaulov A. , Bauer B. S. , Lindemuth I. R. , Makhin V. , Presura R. , Ryutov D. D. , Sheehey P. T. , Siemon R. E. , Sotnikov V. I.
Published: April 2004

A wall confined plasma in an inverse-pinch configuration holds potential as a plasma target for Magnetized Target Fusion (MTF) as well as a simple geometry to study wall-confined plasma. An experiment is planned to study the inverse-pinch configuration using the Zebra Z pinch [B. S. Bauer et al., AIP Conference Proceedings Vol. 409 (American Institute of Physics, Melville, 1997), p. 153] of the Nevada Terawatt Facility at the University of Nevada, Reno (UNR). The dynamics of the discharge formation have been analyzed using analytic models and numerical methods. Strong heating occurs by thermalization of directed energy when an outward moving current sheet (the inverse pinch effect) collides with the outer wall of the experimental chamber. Two-dimensional magnetohydrodynamic simulations show Rayleigh–Taylor and Richtmyer–Meshkov like modes of instability, as expected because of the shock acceleration during plasma formation phase. The instabilities are not disruptive, but give rise to a mild level of turbulence. The conclusion from this work is that an interesting experiment relevant to wall confinement for MTF could be done using existing equipment at UNR.
The maximum energy of 3He ions accelerated by current-driven instabilities
Authors: Toida Mieko , Okumura Hayato
Published: April 2004

Nonlinear development of strong current-driven instabilities can cause selective acceleration of He3 ions through H cyclotron waves with frequencies ω≃2ΩHe3 (ΩHe3 is the cyclotron frequency of He3). Energies of these ions are studied theoretically and numerically. Theoretical expressions for the wave numbers, k∥ and k⊥, of the H cyclotron waves with ω≃2ΩHe3 and for the maximum energy of He3 ions are presented. As initial electron drift speed vd increases, the value of k⊥ decreases; which leads to the increase in the maximum He3 energy. Simulation results for the wave numbers and for the maximum He3 energy obtained by a two-dimensional, electrostatic, particle code are quantitatively in good agreement with the theory. It is also shown that when the initial electron drift energy is of the order of 10 keV, many He3 ions can be accelerated to energies of the order of MeV/n.
Confinement of antihydrogen with a radio frequency, cylindrical cavity mode
Authors: Ohkawa T. , Miller R. L.
Published: April 2004

Antihydrogen may be confined by radio frequency cavity mode fields at sufficiently low temperature, estimated to be T<9×10−3 K.
Low level plasma formation in a carbon velvet cesium iodide coated cathode
Authors: Shiffler D. , Heggemeier J. , LaCour M. , Golby K. , Ruebush M.
Published: April 2004

Field emission cathodes have been a subject of research for many years. These cathodes hold the promise of effective electron emission in the absence of a heater. Such devices find application in the high power microwave (HPM) arena, as well as the conventional microwave industry and other areas such as flat panel displays. Over the past several years the Air Force Research Laboratory began to focus on cesium iodide cathodes as a field emission cathode of some interest. Previously reported results demonstrated a cesium iodide coated carbon velvet cathode capable of over one million pulses of operation with no degradation of emission. However, the exact emission mechanism remains somewhat unclear. This paper presents results showing that plasma formation on the cathode surface remains minimal at 1 μs pulse lengths. While ionized cesium and iodine lines exist in the light spectrum from the diode, these lines remain quite small, with the fluorescent emission from solid cesium iodide dominating the optical spectra in the diode. Hence, we propose that the cesium iodide coated carbon velvet operates in a space charge limited regime with pure field emission alone.
Stationary plasma states far from equilibrium
Authors: Treumann R. A. , Jaroschek C. H. , Scholer M.
Published: April 2004

The appearance of generalized-Lorentzian distribution functions, a physical generalization of the so-called “κ-distributions,” in collisionless space plasmas is a frequent phenomenon. They represent “stationary states far from thermal equilibrium.” It is argued in which way they can be understood from kinetic theory of quasistationary highly correlated (presumably turbulent) states. Fits of model generalized-Lorentzian distributions to measured distributions in the magnetospheric tail and the auroral plasmas are presented. These fits provide reasonable values of density and temperature in the regions under consideration. Moreover, an expression for the Debye screening length is derived for such generalized-Lorentzian plasmas showing that the screening in correlated plasmas is reduced in comparison with Maxwellian plasmas.
Fundamental issues on kappa-distributions in space plasmas and interplanetary proton distributions
Authors: Leubner M. P.
Published: April 2004

Numerous in situ observations indicate clearly the presence of nonthermal electron and ion structures as ubiquitous and persistent feature in a variety of astrophysical plasma environments. In particular, the detected suprathermal particle populations are accurately represented by the family of κ-distributions, a power-law in particle speed. After clarifying the characteristics of high-energy tail distributions under various space plasma conditions, different generation mechanisms of energetic particles are introduced where numerical simulations of wave–particle interaction based on a Fokker–Planck approach demonstrate how Landau interaction ultimately leads to κ-like distributions. Because of lack of theoretical justification, the use of the analytical form of κ-functions was frequently criticized. It is shown that these distributions turn out as consequence of an entropy generalization favored by nonextensive thermo-statistics, thus providing the missing link for powerlaw models of suprathermal tails from fundamental physics, along with a physical interpretation of the structure parameter κ. Moreover, with regard to the full nonextensive formalism, compatible also with negative values of κ, it is demonstrated that core–halo distribution structures, as observed for instance under typical interplanetary plasma conditions, are a natural content of the pseudo-additive entropy concept. The significance of the complete κ-distribution family with regard to observed core–halo electron and double-humped ion velocity space characteristics is illuminated, where the observed peak separation scale of interplanetary proton distributions is compatible with a maximum entropy condition.
The influence of laser field noise on controlled quantum dynamics
Authors: Sola Ignacio R. , Rabitz Herschel
Published: April 2004

The influence of laser noise on the dynamics of simple quantum systems is analyzed. An anharmonic ladder is chosen for illustration and several pulses are obtained that optimize the yield of a quantum transition by constraining the laser parameters. The following models of laser noise are introduced: Amplitude white noise, phase white noise, frequency white noise and shot-to-shot static noise in the different pulse parameters. It is shown that the optimal pulses are robust to white amplitude noise, since the system acts as a dynamical filter. White phase noise affects the optimal pulses in a similar way by reducing the pulse area. This effect can be easily compensated for by pulse amplitude rescaling, up to a high level of noise. White frequency noise reduces the pulse area and induces spectral broadening, more strongly affecting the high frequency components. It can be partially compensated for by amplitude rescaling. The effects of static noise in the parameters cannot be easily corrected. It is shown that optimal pulses that drive n-photon transitions become more sensitive to noise in the amplitude and less sensitive to noise in the frequency as n increases. The effects of noise in the relative phase rapidly become constant for a large number of interfering pathways.