bluuebunny/crossref_metadata_2025 huggingface dataset:
Scotopic Illumination Enhances Entrainment of Circadian Rhythms to Lengthening Light:Dark Cycles
Authors: Gorman Michael R. , Kendall Magdalena , Elliott Jeffrey A.
Published: January 2005

Endogenously generated circadian rhythms are synchronized with the environment through phase-resetting actions of light. Starlight and dim moonlight are of insufficient intensity to reset the phase of the clock directly, but recent studies have indicated that dim nocturnal illumination may otherwise substantially alter entrainment to bright lighting regimes. In this article, the authors demonstrate that, compared to total darkness, dim illumination at night (< 0.010 lux) alters the entrainment of male Syrian hamsters to bright-light T cycles, gradually increasing in cycle length (T) from 24 h to 30 h. Only 1 of 18 hamsters exposed to complete darkness at night entrained to cycles of T > 26 h. In the presence of dim nocturnal illumination, however, a majority of hamsters entrained to Ts of 28 h or longer. The presence or absence of a running wheel had only minor effects on entrainment to lengthening light cycles. The results further establish the potent effects of scotopic illumination on circadian entrainment and suggest that naturalistic ambient lighting at night may enhance the plasticity of the circadian pacemaker.
The Menstrual Cycle and Susceptibility to Virtual Simulation Sickness
Authors: Clemes Stacy A. , Howarth Peter A.
Published: January 2005

Virtual simulation sickness (VSS) is a form of visually induced motion sickness that can result fromimmersion in a virtual environment (VE). As in their susceptibility to the sickness induced by real motion, womenhave been reported to be more susceptible than men to VSS, yet the reason for this difference is not known. The aim of the current study was to investigate the influence of themenstrual cycle on susceptibility to VSS in 16 naturally cycling women and to compare the responses of this group with control groups consisting of 1) 16 premenopausal women taking a combined monophasic oral contraceptive and 2) 16 men. All female participants were immersed in a nauseogenic VE on days 5, 12, 19, and 26 of their menstrual/pill cycle. These days were chosen because they fall in line with peaks and troughs of ovarian hormone levels. Menstrual cycle phase was confirmed by salivary estradiol and progesterone levels. A 4-week “pseudo-cycle” was assigned to the male participants. Hormone analysis revealed that 9 participants in the experimental group had been tested at the desired phases of their cycle. These participants exhibited a significant increase in susceptibility to VSS on day 12 of their cycle. The hormone analysis also showed that the cycles of the 7 remaining members of the experimental group had not precisely followed the expected pattern, and so these people had been tested on days that did not coincide with peaks and troughs of ovarian hormone levels. No consistent variation in susceptibility was observed over the cycle in these volunteers. In addition, no change in susceptibility was observed over the pill cycle of the oral contraceptive group nor over the pseudo-cycle applied to the male control group. The authors conclude that susceptibility to VSS varies over the menstrual cycle as a consequence of hormonal variation.
Long-Term Constant Light Induces Constitutive Elevated Expression of mPER2 Protein in the Murine SCN: A Molecular Basis for Aschoff’s Rule?
Authors: Muñoz Marta , Peirson Stuart N. , Hankins Mark W. , Foster Russell G.
Published: January 2005

Circadian rhythms in behavior, metabolism, and physiology are based upon transcriptional/translational feedback loops involving a core set of clock genes that interact to regulate their own expression. In mammals, the SCN is the site of a master biological clock regulating circadian locomotor rhythms. The products of the clock genes mPer1, mPer2, mCry1, and mCry2 form essential components of both negative and positive elements within the SCN oscillator. The primary aims of this study were to examine clock gene abundance under longterm LL in an attempt to provide molecular correlates of the lengthened tau and daily phase delays described by Aschoff’s rule. Wheel-running behavior was recorded frommice maintained in eitherDDor LLfor 50 days. The abundance of the clock genes mPer1, mPer2, mCry1, and mCry2 and their protein products was then examined (every ~4 h) within the SCN using in situ hybridization and immunocytochemistry. Under LL conditions, mPer1, mPer2, mCry1, and mCry2 messages remained rhythmic, although the waveform of mCry2 was altered compared to DD. In LL, mPER1, mCRY1, and mCRY2 protein levels were also rhythmic and comparable to the patterns observed in DD. However, mPER2 is elevated and constitutively expressed under LL. Thus, rhythmic expression of these clock genes is not dependent on the rhythmic production of mPER2, and the acute up-regulation of mPer1 and mPer2 described for short (nonparametric) light pulses is not sustained under LL conditions. These findings suggest that mPER2 is important for the generation of phase delays in the molecular clockwork, providing a possible molecular explanation for Aschoff’s rule: LL lengthens the circadian period by inhibiting the degeneration of mPER2, and constitutively elevated levels of mPER2 enhance the phase-delaying limb of the molecular oscillator.
Binocular Interactions in the Entrainment and Phase Shifting of Locomotor Activity Rhythms in Syrian Hamsters
Authors: Park Jin Ho , Paul Matthew J. , Butler Matthew P. , Zucker Irving
Published: January 2005

To assess binocular interactions and possible ocular dominance in entrainment of circadian rhythms, Syrian hamsters maintained in LL were subjected for several weeks to schedules of eye occlusion with opaque contact lenses. In separate groups, the opaque lens was inserted into the left or right eye for 12 h at the same clock time each day. The left and right eyes of other groups were alternately occluded for 12 h each day, with initial occlusion of either the left or right eye for different groups. Amajority of hamsters entrained their locomotor activity rhythm when 1 eye was occluded for 12 h. The modified visual input imposed by covering 1 eye is sufficient to induce entrainment. Locomotor rhythms of most animals in which the 2 eyes were alternately occluded for 12 h each day phasedelayed onset of activity during the 1st few days of the lensing procedure; activity onset then free ran with • < 24 h for several weeks until entraining with • of 24 h regardless of whether the left or right eye was initially occluded. Entrainment eventually occurred when activity onset coincided with occlusion of the eye contralateral to the one that was first lensed. Photic and nonphotic explanations for eventual entrainment of locomotor rhythms are discussed, and evidence for asymmetrical photic input from the 2 eyes to the SCN is considered
Single gene effects in mouse models of host: pathogen interactions
Authors: Fortier Anne , Min-Oo Gundula , Forbes John , Lam-Yuk-Tseung Steven , Gros Philippe
Published: January 2005

Inbred mouse strains have been known for many years to vary in their degree of susceptibility to different types of infectious diseases. The genetic basis of these interstrain differences is sometimes simple but often complex. In a few cases, positional cloning has been used successfully to identify single gene effects. The natural resistance-associated macrophage protein 1 (Nramp1) gene (Slc11a1) codes for a metal transporter active at the phagosomal membrane of macrophages, and Nramp1 mutations cause susceptibility to Mycobacterium, Salmonella, and Leishmania. Furthermore, recent advances in gene transfer technologies in transgenic mice have enabled the functional dissection of gene effects mapping to complex, repeated parts of the genome, such as the Lgn1 locus, causing susceptibility to Legionella pneumophila in macrophages. Finally, complex traits such as the genetically determined susceptibility to malaria can sometimes be broken down into multiple single gene effects. One such example is the case of pyruvate kinase, where a loss-of-function mutation was recently shown by our group to be protective against blood-stage infection with Plasmodium chabaudi. In all three cases reviewed, the characterization of the noted gene effect(s) has shed considerable light on the pathophysiology of the infection, including host response mechanisms.
Nanoscale Irregularity Analysis of Carbon Fibre Surfaces with a High-Resolution αS-Plot
Authors: Fukasawa K. , Ohba T. , Kanoh H. , Toyoda T. , Kaneko K.
Published: January 2005

Exfoliated carbon fibres (ECFs) were prepared from preheated mesophase pitch-based carbon fibre by electrochemical treatment. The nitrogen adsorption isotherms on ECFs were measured at 77 K. All the nitrogen adsorption isotherms were transformed into αS-plots using the standard adsorption isotherms for carbon blacks of different crystallinities and the GCMC simulation isotherm. Using the standard isotherm of well-crystallized carbon black, the αS-plot for the ECF prepared from carbon fibre preheated at 3273 K was almost linear, while αS-plots obtained using the standard isotherm of well-crystallized carbon black and the simulated form had have a downward and an upward deviation, respectively. The αS-plots of carbon samples having similar nanoscale crystallite sizes were close to each other, showing that αS-plot analysis was effective for determining the average surface irregularity structure in the nanoscale range.
Chemical Composition of the Copper/Benzotriazole Interface in the Presence of Acetic Acid Vapour at Low Humidities
Authors: Cano E. , Bastidas D.M. , Simancas J. , López-Caballero J.A. , Bastidas J.M.
Published: January 2005

Studies were made of the chemical composition of the copper products formed at 43, 58 and 78% relative humidity (RH) in contaminated (10-ppm acetic acid vapour) and uncontaminated environments in the presence and absence of the volatile corrosion inhibitor benzotriazole (BTA) for 7 d at 30°C. Such studies were conducted using X-ray photoelectron spectroscopy (XPS). General XPS spectra over a wide binding energy region showed C and O peaks in addition to those corresponding to the different copper compounds. Copper specimens exposed to acetic acid vapour in the presence of BTA also exhibited N emissions. The main compounds formed were cuprite (Cu2O), copper hydroxide [Cu(OH)2], copper acetate and copper-benzotriazole (Cu-BTA) complexes.
Adsorption and Catalytic Properties of Co/ZSM-5 Zeolite Catalysts for CO Oxidation
Authors: Oleksenko Ludmila P. , Yatsimirsky Vitaly K. , Telbiz German M. , Lutsenko Larisa V.
Published: January 2005

Studies were made of the adsorption and acidic properties, the coordination state of the Co ion in Co2+, Co3+-containing ZSM-5 zeolite systems and the catalytic activity of these zeolites in CO oxidation. A correlation was established between the catalytic activity of these Co-containing zeolites and the number of Brönsted acid sites on the surface and in the system bulk as obtained by different methods. The content of various forms of Co ion coordination states and the ratio of Brönsted to Lewis acidic sites at the surface of the Co-containing zeolites defined their activity in CO oxidation.
Modelling the Effects of Adsorbent Dose and Particle Size on the Adsorption of Cr(VI) Ions from Aqueous Solutions
Authors: Kobya M. , Demirbas E. , Bayramoglu M.
Published: January 2005

Activated carbon was prepared from hazelnut shell with chemical carbonization using concentrated sulphuric acid. The adsorption tests were carried out in an agitated batch system with a fixed initial Cr(VI) ion concentration and varying adsorbent particle sizes and doses. The adsorption of Cr(VI) ions correlated strongly with these two variables. Two simple empirical models were examined for predicting the percentage of Cr(VI) ion adsorbed. Both models exhibited good correlation coefficients. The best model was selected on the basis of the standard deviation between the calculated and experimental values. The Freundlich adsorption isotherm provided the best correlation for the adsorption of Cr(VI) ions onto the carbon. This isotherm was used to fit the experimental adsorption capacity data and allowed the model parameters to be calculated and correlated with the particle size.
Removal of Pb(II) Ions from Contaminated Water by Polymer-Supported Ultrafiltration
Authors: Yurlova L.Yu. , Kryvoruchko A.P.
Published: January 2005

Through the ultrafiltration of water containing Pb(II) ions and poly(ethyleneimine) as an example, it was possible to determine the Pb(II) ion retention coefficients by UPM-20 membranes and the corresponding transmembrane fluxes. The optimal parameters, i.e. pH and concentration ratio CPb(II)/CPEI, necessary to remove Pb(II) ions from aqueous media using a complexation/ultrafiltration technique (polymer-supported ultrafiltration) were also determined. The state of water in the membranes and its quantity were found using differential scanning calorimetric methods.

On the basis of investigations by the method of differential scanning calorimetry, it was possible to assume that the layers of Pb(II)-poly(ethyleneimine) complexes and Pb(II) hydroxo complexes were situated either on the membrane surface or in its pores. In addition, a relationship was established between the transmembrane transfer of Pb(II) ions and the amount of free and bound water in the membrane under investigation.
Toxic Waste Removal from Aqueous Solutions by Polyaniline: A Radiotracer Study
Authors: Gupta R.K. , Shankar Som
Published: January 2005

A radiotracer technique was used to study the removal of Hg(II) ions from aqueous solutions by polyaniline. It was shown that an increase in the concentration of the adsorptive (10−7–10−2 M), temperature (303–333 K) and pH (ca. 3–10) enhanced the removal of these ions. The first-order uptake of Hg(II) ions conformed to the Freundlich and Dubinin and Radushkevich (D–R) isotherms over the entire adsorptive concentration range (10−7–10−2 M), whereas the Langmuir isotherm was followed only at moderate concentrations. Thermal data showed that this process was endothermic in nature. The radiation stability of polyaniline was also investigated by exposing it to an 11.1 GBq (Ra/Be) source associated with a γ-dose of 1.72 Gy/h. Irradiation had practically no significant effect on the adsorption capacity of polyaniline. Desorption experiments showed that the process of Hg(II) ion adsorption by polyaniline was almost irreversible and chemisorptive in nature.
The Use of Activated Carbons with Basic Properties for the Treatment of 2-Chlorophenol
Authors: El-Sheikh Amjad H. , Newman Alan P. , Al-Daffaee Hafid K. , Phull Suki S. , Lynch Daniel E.
Published: January 2005

A range of basic activated carbons was prepared from single cultivar Jordanian olive stones and their chemical composition, textural properties and surface groups investigated. One of the samples was de-ashed and then oxidized using concentrated nitric acid to study the effects of inorganic content and surface oxidation on its adsorption capacity towards 2-chlorophenol (2-CP). Commercial samples with combined acidic and basic properties were also tested with respect to 2-CP adsorption.

An attempt was made to correlate the total basicity with the adsorption constants of the Langmuir equation and with other properties. These properties included burn-off, apparent surface area, micropore volume, total pore volume and Methylene Blue (MB) adsorption surface area. The total basicity had no relationship with any adsorption parameter. However, total basicity was found to have a relationship with the total pore volume, the micropore volume, MB adsorption and burn-off. The BET surface area showed only a very weak relationship with the total basicity. Burn-off had a relationship with the relative affinity of the adsorbate and the surface and Langmuir constants, but not with the adsorption capacity. De-ashing the sample using HF/HCl decreased the total basicity and MB adsorption but increased the total acidity and the capacity towards 2-CP uptake. The mineral contents of both prepared and commercial samples were analyzed and found to play no role in the adsorption of 2-CP.
Adsorption of Chromium(VI) Ions from Water by Carbon Nanotubes
Authors: Di Ze-Chao , Li Yan-Hui , Luan Zhao-Kun , Liang Ji
Published: January 2005

Carbon nanotubes (CNTs), a new type of carbon material, show exceptional adsorption capability and a high adsorption efficiency for the removal of chromium(VI) ions from water over a broad pH range extending from 4.0 to 7.5. The largest adsorption capacity for CNTs occurred at pH 7.5 and attained a value of 20.56 mg/g at an equilibrium Cr(VI) ion concentration of 33.28 mg/l. The adsorption rate of Cr(VI) ions was fast over the first 20 min with the adsorption capacity of the CNTs reaching 15 mg/g rapidly. The experimental results suggest that CNTs can be employed as good adsorbents for Cr(VI) ions and have great potential for applications in environmental protection.
Effectiveness of Noise Barriers Tilted towards the Traffic Way over Bridges
Authors: Ibrahim M. A.
Published: January 2005

Traffic noise over bridges and its impacts can be substantially reduced with road side barriers. A single barrier erected on one side of a bridge way can often provide the most effective solution. A single barrier may not always be sufficient, particularly in urban settings. In these cases, barriers may be necessary on both sides of the bridge. This paper presents a study of the effectiveness of barriers tilted towards the traffic with different angles and shapes to reduce the effect of the reflected sound waves from the second barrier. The insertion loss was determined at many points distributed horizontally and vertically behind the barrier.
Noise Analysis of Heavy Earth Moving Machinery Deployed in Opencast Mines and Development of Suitable Maintenance Guidelines for its Attenuation - Part 2
Authors: Vardhan Harsha , Rao Y.V. , Karmakar N.C.
Published: January 2005

Worldwide, increasingly stringent regulations are coming into force, limiting the exposure of workers to industrial noise. Industrial noise and its consequences is thus growing in importance to employers, local and central government officials, trade unions, occupational hygienists and physicians and insurers. India is not an exception for this. The mining industry in India is facing serious problem of noise due to increasing demand for minerals for which large capacity machines are being deployed producing high noise levels. To know the status and to control the noise, the S&T Department of the Ministry of Coal, Government of India sponsored a research project in the area of noise pollution and its control for opencast projects. To start with, a detailed literature survey was carried out in the area of noise pollution and its control in the mining industry, embracing equipment like from Heavy Earth Moving Machinery (HEMM), compressors, workshops, pneumatic drills, processing plants etc., to know the quantum of work done in India and worldwide. The various aspects studied in this project were the daily noise dose and/or noise exposure level of the operators of various types of heavy earth moving machinery and its assessment, noise characteristics at different operating conditions of the machine, analysis of noise coming out from different parts of the machine, analysis of noise at different distances from the machine for different frequency components and the most important one i.e., impact of periodic maintenance on the noise characteristics of machines and to find out with which maintenance schedule there is maximum fluctuation in the noise level and to evolve a technique for attenuating the noise generated from these machines as well as to reduce the operator's exposure to high noise levels. This paper highlights the results of this research project.
The White Edge of the Margin: Textuality and Authority in Biak, Irian Jaya, Indonesia
Authors: Rutherford Danilyn
Published: January 2005

In Biak, Irian Jaya, in the far east of Indonesia, foreign slogans, narratives, and books are considered a crucial source of authority. In this article, I examine how amber beba (big foreigners), the Biak term for respected leaders, harness the potency attributed to distant lands by presenting their words as translations of an alien text. I explore the implications of this strategy for pursuing authority by examining the worldview expressed in big foreigners' translations of the Bible and other imported works. The case of Biak calls into question scholarly treatments that have taken literacy and Christian conversion as setting the stage for the emergence ofpostcolonial forms of hegemony. In valorizing the textual aspects of outsiders' words, Biaks reproduce a boundary between local and national structures of meaning, keeping foreign orders at a distance even as they tap them for authority and power. [leadership, literacy, translation, Christianity, intercultural relations, postcolonial societies, modernity]
Moving Stories: Displacement and Return in the Narrative Production of Yaqui Identity
Authors: Erickson Kirstin
Published: January 2005

Among the Yaqui Indians of Mexico, discourses that inscribe ethnicity connect space, place, and history. In this article, I examine narratives about the Yaqui exile at the turn of the twentieth century. I argue that Yaqui identity and concepts of “homeland” are imagined through narratives about movement. Memories of displacement and return, and everyday talk about travel, link space to fields of power and imbue the homeland with a set of intense cultural meanings.
Proto‐Metropolis Meets Post‐Metropolis in Kumasi, Ghana
Authors: Clark Gracia
Published: January 2005

Globalization has transformed many of the transnational connections experienced by the diverse constellation of residents, emigrants and immigrants attached to Kumasi. Despite its modest size, these processes have not erased its material and symbolic primacy within its regional and Asante diasporic hinterland. The international flows of people and cultural and economic resources associated with metropolitan life have characterized Kumasi since its foundation and remain central to its meaning, so their intensification reinforces rather than threatens the continuity of its self‐imagination. Residents and other constituents, well aware of powerful external forces intervening in their everyday lives, show their loyalty by investing heavily in key hierarchies still managed in Kumasi. Asante openly innovate within these heal institutions of chieftaincy, house building, funerals, and public ceremonies, to take full advantage of greater mobility, new communication technologies and multiple cross‐cutting identities, [migration, investment, innovation, Asante, Africa]
Imagining the Metropolis, Globalizing the Nation: Dar Es Salaam and national culture in Tanzanian cartoons
Authors: Lewinson Anne
Published: January 2005

Africa's cities in general and particularly its metropolises are the setting within which Africans take goods and practices derived from the global economy and embed them into local contexts. Africans use these translated items to debate salient issues in their lives, and one most crucial issue is the city itself—its nature and role in their lives. Swahili‐language cartoon magazines in Tanzania exemplify such a debate. Since their inception in the late 1980s, these urbanfocused texts portray Dar es Salaam as Tanzania's premier city, the place where Tanzanians find foreign commodities, Europeanized behavior, and imported fashions. Through the magazines, the authors articulate images of the metropolis, its residents, and their relationships with non‐urbanites. Yet the citys image has not remained constant over time. In the early 1990s, cartoonists primarily highlighted urban versus rural ways and ethnicity, creating a portrait of the city as a place where heterogeneous groups came together to form the nation. By the late 1990s, however, the emphasis shifted to debating trends in urbanism, national policies, and the impact of globally‐derived culture upon Tanzanian society. As cartoonists portray a different place for Dar es Salaam relative to the imagined communities of the nation and the globe, they highlight changes m the metropolis and Tanzania itself. [Tanzania, city, cartoons, globalization, popular culture]
Nocturnal Arterial Oxygen Saturation and Academic Performance in a Community Sample of Children
Authors: Urschitz Michael S. , Wolff Judith , Sokollik Christiane , Eggebrecht Esther , Urschitz-Duprat Pilar M. , Schlaud Martin , Poets Christian F.
Published: January 2005

Objective. Hypoxemia, often assessed via pulse oximetry, is associated with neurocognitive deficits in children. The best way to qualify hypoxemia, or which level of hypoxemia already affects cognition, is unknown.

Methods. We assessed the association of pulse oximetry-derived variables that qualify hypoxemia with impaired academic performance in mathematics in a population-based cross-section of 995 primary school children who underwent overnight home recordings of motion-resistant new-generation pulse oximeter saturation (Spo2). Impaired academic performance in mathematics was based on the last school report and defined as grade 4 to 6 on a 6-point scale (ie, approximately the lowest quintile grades).

Results. Of 10 variables under study, only the nadir of the Spo2 values was significantly associated with impaired performance. Categories of this variable representing mild (ie, 91%–93% Spo2; odds ratio: 1.65; 95% confidence interval: 1.06–2.56) and moderate hypoxemia (ie, ≤90% Spo2; odds ratio: 2.28; 95% confidence interval: 1.30–4.01) both were associated with impaired performance in mathematics.

Conclusions. We suggest using the nadir of the Spo2 values in an overnight study to qualify hypoxemia in future studies. This variable may predict neurocognitive deficits in school children. Mild hypoxemia, as yet widely considered benign, may already affect cognition in childhood.
Letrozole Significantly Improves Growth Potential in a Pubertal Boy With Growth Hormone Deficiency
Authors: Zhou Ping , Shah Bina , Prasad Kris , David Raphael
Published: January 2005

Clinical experience with using an aromatase inhibitor to suppress estrogen production during puberty for improvement of growth potential in adolescents with short stature is limited. This report documents treatment of such a patient with a combination of growth hormone and letrozole, a third-generation aromatase inhibitor. Our case demonstrates a favorable outcome on a short-term basis.
USCensus Bureau
Authors: Wright Tommy
Published: January 2005

The US Census Bureau (official name is US Bureau of the Census) collects and provides data about the people and economy of the United States. Most of its data are collected by use of periodic censuses and more frequent sample surveys. Some data are produced by statistical modeling and estimation. The data products of the Census Bureau are primarily either counts of units in an entire universe being studied or characteristics of these units. This article provides selected historical highlights of the Census Bureau and its censuses and sample surveys and associated details of its demographic and economic data programs.
Influence of the length of the plasticating system on selected characteristics of an autothermal extrusion process
Authors: Sikora Janusz W. , Sasimowski Emil
Published: January 2005

The presented paper aims to determine the influence of the length of the plasticating system on the course of an autothermal extrusion process. Three special screws were used, of the relationship of the length of the operating part to diameter of the screw L/D = 20, 25, and 30, with a tip for intensive shearing and mixing, assigned for polyethylene processing, and five screw rotation frequencies were applied. The conducted research consisted of the measurement, during the extrusion, of the factors studied directly and in the calculation, and on their basis, the values characterizing this process. It is stated that the change of the length of the plasticating system in a significant way influences the dependences determining polymer flow rate, temperature and pressure of the processed polymer, extrusion velocity, specific energy consumption, and energy efficiency of the extruder; that is, the whole characteristic of an autothermal extrusion process. © 2005 Wiley Periodicals, Inc. Adv Polym Techn 24:21–28, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.adv20021
All Science Is Interdisciplinary—From Magnetic Moments to Molecules to Men (Nobel Lecture)
Authors: Lauterbur Paul C.
Published: January 2005

Merely by chance, says Paul Lauterbur, one of the recipients of the Nobel Prize for Physiology or Medicine in 2003, were NMR imaging techniques his main research focus for many years. In his Nobel Lecture, he describes important facets of his life and his scientific carrier that led him from silicones to the clinical application of NMR spectroscopy and later to the question of how chemistry can help in explaining biology.
Lepidopteran herbivory and oral factors induce transcripts encoding novel terpene synthases in Medicago truncatula
Authors: Gomez Susana K. , Cox Mandy M. , Bede Jacqueline C. , Inoue Kentaro , Alborn Hans T. , Tumlinson James H. , Korth Kenneth L.
Published: January 2005

Terpenes are an important class of defense compounds that accumulate in plants after pathogen infection or arthropod injury. Sequences predicted to encode terpene synthases were selected from an expressed sequence tag (EST) database of Medicago truncatula. Four putative terpene synthase clones (MtTps1–MtTps4), originating from a chewing insect‐damaged M. truncatula leaf cDNA library, were isolated. Transcript levels of each gene examined increased in response to artificial wounding, Spodoptera exigua herbivory, and treatment with volatile methyl jasmonate (meJA). Addition of S. exigua regurgitant to wound sites triggered transcript accumulation of MtTps1 and levels increased with higher concentrations of regurgitant. Furthermore, induction of MtTps1 occurred after application of N‐linolenoyl‐glutamate or N‐linoleoyl‐glutamate, factors found in lepidopteran regurgitant. Genomic DNA blots indicate that each of the putative proteins is encoded by a single‐copy gene or a small gene family. Proteins encoded by MtTps3 and MtTps4 are imported into the soluble fraction of chloroplasts in in vitro assays, whereas proteins encoded by MtTps1 and MtTps2 are not imported into chloroplasts. Combined with sequence comparisons of multiple plant terpene synthases, the import data indicate that MtTps1 and MtTps2 likely encode sesquiterpene synthases and that MtTps3 and MtTps4 encode mono‐ or di‐terpene synthases. In addition to serving as a valuable model legume species for genomic studies, M. truncatula should prove a valuable source of novel terpene‐producing enzymes. Induction of wound‐responsive genes by insect oral factors suggests that M. truncatula senses biotic damage through the presence of elicitors originating in the herbivore. Arch. Insect Biochem. Physiol. 58:114–127, 2005. © 2005 Wiley‐Liss, Inc.
Lophine derivatives as versatile analytical tools
Authors: Nakashima Kenichiro
Published: January 2005

Lophine (2,4,5‐triphenylimidazole) derivatives as versatile analytical tools in biomedical sciences are described. Chemiluminescence (CL) and fluorescence (FL) properties of the lophine derivatives are first demonstrated including the CL reaction mechanism, effects of substituents on CL yields, FL spectral behaviors, etc. Next, analytical applications to the determination of metal ions such as cobalt (II) and chromium (VI) are discussed. Finally, the application studies of lophine derivatives as CL and FL reagents for the determination of organic substances in biological materials are presented. Among the derivatives, 2‐(4‐hydrazinocarbonylphenyl)‐4,5‐diphenylimidazole (HCPI) and 4‐(4,5‐diphenyl‐1H‐imidazol‐2‐yl)benzoyl chloride (DIB‐Cl) are studied, with their excellent properties as labeling reagents for fatty acids and amines and/or phenols, respectively, in high‐performance liquid chromatography. The utility of boronic acid derivatives as CL enhancers is also discussed in this review. Copyright © 2003 John Wiley & Sons, Ltd.
Simultaneous quantification of budesonide and its two metabolites, 6β‐hydroxybudesonide and 16α‐hydroxyprednisolone, in human plasma by liquid chromatography negative electrospray ionization tandem mass spectrometry
Authors: Wang Yaning , Tang Yufei , Moellmann H. , Hochhaus Günther
Published: January 2005

A sensitive, rapid and selective liquid chromatography negative electrospray ionization tandem mass spectrometry [LC‐(−)ESI‐MS‐MS] method has been developed and validated for the simultaneous quantification of budesonide (BUD) and its major metabolites, 6β‐hydroxybudesonide (OH‐BUD) and 16α‐hydroxyprednisolone (OH‐PRED) in human plasma. The method was validated over a linear range from 0.1 to 10 ng/mL for all three analytes using a solid‐phase extraction procedure with 9‐fluoro‐hydrocortisone as the internal standard. The between‐day and within‐day coefficients of variation for all compounds were ≤20% at the concentrations of lower limit of quantification and ≤15% at other quality control concentrations. The utility of this assay was demonstrated by monitoring BUD, OH‐BUD and OH‐PRED plasma concentrations in one healthy subject for 24 h following a 3 mg oral dose of budesonide, administered as a pH modified release capsule (Budenofalk®) to healthy volunteers. Copyright © 2003 John Wiley & Sons, Ltd.
Chromatographic competitive binding immunoassays: a comparison of the sequential and simultaneous injection methods
Authors: Nelson Mary Anne , Reiter Wanda S. , Hage David S.
Published: January 2005

Two approaches for performing competitive binding immunoassays by HPLC and other flow‐based systems are the simultaneous and sequential injection methods. Both these techniques make use of a column with a limited amount of antibody, onto which is injected a sample and a fixed amount of a labeled analyte analog. An indirect measure of the unlabeled analyte in the sample is then obtained by looking at the amount of analog in either the nonretained or retained peaks. In the simultaneous injection mode, the sample and labeled analog are applied at the same time to the column, while in the sequential mode the sample is injected first, followed by the analog. This results in a difference in the analytical characteristics of these two approaches. This study used chromatographic theory and previous data obtained for injections of human serum albumin (HSA) onto an anti‐HSA antibody column to compare the response, detection limits, range, and sensitivity of these methods. Under equivalent conditions, it was found that the sequential method always provided the best lower limit of detection and sensitivity. However, the simultaneous mode had a broader dynamic range and higher upper limit of detection. From these observations, several guidelines were developed regarding the use and selection of such assays for new applications. Copyright © 2003 John Wiley & Sons, Ltd.
Strategies for the purification of laminin‐10 for studies on colon cancer metastasis
Authors: Zamurs Laura , Pouliot Normand , Gibson Peter , Hocking Glenn , Nice Edouard
Published: January 2005

Signals from the epidermal growth factor (EGF) receptor family are thought to combine with integrin‐dependent adhesion to laminins to contribute to disease progression and metastasis in cancer. To date, little is known about the mechanisms by which these signals interact. Recently, we have shown that the colon cancer cell line LIM1215 secretes and adheres to laminin‐10 through multiple integrin receptors, and that EGF stimulates spreading and migration of these cells on the same substrate. Additionally laminin‐10/11 has been shown by immunohistochemistry to be present at the invasive edge of moderately differentiated colon cancers. To enable detailed structure–function studies to be undertaken, it is important to be able to rapidly obtain highly purified native laminin‐10 from bulk biological samples in reasonable yield. The development of a multidimensional micropurification scheme to achieve this is presented and compared with other reported methods for the purification of laminins. Copyright © 2003 John Wiley & Sons, Ltd.
Reaction Mechanism of Porphyrin Metallation Studied by Theoretical Methods
Authors: Shen Yong , Ryde Ulf
Published: January 2005

We have studied the reaction mechanism for the insertion of Mg2+and Fe2+into a porphyrin ring with density functional calculations with large basis set and including solvation, zero‐point and thermal effects. We have followed the reaction from the outer‐sphere complex, in which the metal is coordinated with six water molecules and the porphyrin is doubly protonated, until the metal ion is inserted into the deprotonated porphyrin ring with only one water ligand remaining. This reaction involves the stepwise displacement of five water molecules and the removal of two protons from the porphyrin ring. In addition, a step seems to be necessary in which a porphyrin pyrrolenine nitrogen atom changes its interaction from a hydrogen bond to a metal‐bound solvent molecule to a direct coordination to the metal ion. If the protons are taken up by a neutral imidazole molecule, the deprotonation reactions are exothermic with minimal barriers. However, with a water molecule as an acceptor, they are endothermic. The ligand exchange reactions were approximately thermoneutral (±20 kJ mol−1, with one exception) with barriers of up to 72 kJ mol−1for Mg and 51 kJ mol−1for Fe. For Mg, the highest barrier was found for the formation of the first bond to the porphyrin ring. For Fe, a higher barrier was found for the formation of the second bond to the porphyrin ring, but this barrier is probably lower in solution. No evidence was found for an initial pre‐equilibrium between a planar and a distorted porphyrin ring. Instead, the porphyrin becomes more and more distorted as the number of metal–porphyrin bonds increase (by up to 191 kJ mol−1). This strain is released when the porphyrin becomes deprotonated and the metal moves into the ring plane. Implications of these findings for the chelatase enzymes are discussed.
Organic–Inorganic Hybrids Based on Novel Bimolecular [Si2W22Cu2O78(H2O)]12− Polyoxometalates and the Polynuclear Complex Cations [Cu(ac)(phen)(H2O)]nn+ (n=2, 3)
Authors: Reinoso Santiago , Vitoria Pablo , San Felices Leire , Lezama Luis , Gutiérrez‐Zorrilla Juan M.
Published: January 2005

The reaction of a monosubstituted Keggin polyoxometalate (POM) generated in situ with copper–phenanthroline complexes in excess ammonium or rubidium acetate led to the formation of the hybrid metal organic–inorganic compounds A7[Cu2(ac)2(phen)2(H2O)2][Cu3(ac)3(phen)3(H2O)3][Si2W22Cu2O78(H2O)]⋅≈18 H2O (A=NH4+ (1), Rb+ (2); ac=acetate; phen=1,10‐phenanthroline). These compounds are constructed from inorganic and metalorganic interpenetrated sublattices containing the novel bimolecular Keggin POM, [Si2W22Cu2O78(H2O)]12−, and Cu‐ac‐phen complexes, [Cu(ac)(phen)(H2O)]nn+ (n=2, 3). The packing of compound 1 can be viewed as a stacking of open‐framework layers parallel to the xy plane built of hydrogen‐bonded POMs, and zigzag columns of π‐stacked Cu‐ac‐phen complex cations running along the [11$\bar 1$] direction. Magnetic and EPR results are discussed with respect to the crystal structure of the compounds. DFT calculations on [Cu(ac)(phen)(H2O)]nn+ cationic complexes have been performed, to check the influence of packing in the complex geometry and determine the magnetic exchange pathways.
3‐Fluoropiperidines and N‐Methyl‐3‐fluoropiperidinium Salts: The Persistence of Axial Fluorine
Authors: Sun Aiming , Lankin David C. , Hardcastle Kenneth , Snyder James P.
Published: January 2005

It has previously been shown that the fluorine atom in N‐protonated 3‐fluoropiperidine salts in water strongly prefers the axial orientation in the six‐membered ring chairs. In the present work we examine the proposition that the N‐methyl salts are equally disposed to present axial fluorine. Initially, we explored this point by comparing the structures of the corresponding NH2+, NHMe+, and NMe2+ salts by means of density functional theory (DFT), ab initio, and MMFF force field calculations with and without aqueous solvation models. The predictions unambiguously pointed to axial fluorine for all salts investigated, including those with simultaneous axial F and (N)Me. The calculations were followed by synthesis of the corresponding series of 4,4‐diphenylpiperidinium salts. These were evaluated by one‐ and two‐dimensional NMR spectroscopy in [D6]DMSO to fully corroborate the axial disposition of the fluorine in each of the compounds. X‐ray crystal structure determinations were likewise performed for the diphenyl‐3‐fluoro NH2+ and NMe2+ systems to substantiate axial‐F. Comparison of the X‐ray structures of the fluorinated and unfluorinated NMe2+ salts reveals that the fluorine resides axial in spite of substantial steric compression. While the charge‐dipole phenomenon responsible for the axial‐F conformation in the parent protonated fluoropiperidinium compounds carries over to doubly alkylated salts, we show that it extends to molecular orientation in the packing of the unit cells in the solid state as well. Finally, using the computational methods that successfully motivated our synthesis and structural work, we have made predictions for a number of new structures and re‐examined some parallel results reported by the Eliel group in the early 1970s. Although CF⋅⋅⋅HN hydrogen bonds are reported to be weak and few in number, the CF⋅⋅⋅HN charge‐dipole orienting effect is a powerful directing force that matches the hydrogen‐bond in both its energetic contribution and conformational consequences.
Identification of Muir–Torre syndrome among patients with sebaceous tumors and keratoacanthomas
Authors: Ponti Giovanni , Losi Lorena , Di Gregorio Carmela , Roncucci Luca , Pedroni Monica , Scarselli Alessandra , Benatti Piero , Seidenari Stefania , Pellacani Giovanni , Lembo Luigi , Rossi Giuseppina , Marino Massimiliano , Lucci‐Cordisco Emanuela , de Leon Maurizio Ponz
Published: January 2005

BACKGROUND

The Muir–Torre syndrome (MTS) is an autosomal‐dominant genodermatosis characterized by the presence of sebaceous gland tumors, with or without keratoacanthomas, associated with visceral malignancies. A subset of patients with MTS is considered a variant of the hereditary nonpolyposis colorectal carcinoma, which is caused by mutations in mismatch‐repair genes. The objective of the current study was to evaluate whether a combined clinical, immunohistochemical, and biomolecular approach could be useful for the identification of Muir–Torre syndrome among patients with a diagnosis of sebaceous tumors and keratoacanthomas.

METHODS

The authors collected sebaceous skin lesions and keratoacanthomas recorded in the files of the Pathology Department of the University of Modena during the period 1986–2000. Through interviews and examination of clinical charts, family trees were drawn for 120 patients who were affected by these skin lesions.

RESULTS

Seven patients also were affected by gastrointestinal tumors, thus meeting the clinical criteria for the diagnosis of MTS. In the MTS families, a wide phenotypic variability was evident, both in the spectrum of visceral tumors and in the type of skin lesions. Microsatellite instability was found in five MTS patients: These patients showed concordance with immunohistochemical analysis; moreover, a constitutional mutation in the MSH2 gene was found in 1 patient. Lack of expression of MSH2/MSH6 or MLH1 proteins was evident in the skin lesions and in the associated internal malignancies of 3 patients and 2 patients with MTS, respectively.

CONCLUSIONS

The clinical, biomolecular, and immunohistochemical characterization of sebaceous skin lesions and keratoacanthomas may be used as screening for the identification of families at risk of MTS, a disease that is difficult to recognize and diagnose. Cancer 2005. © 2005 American Cancer Society.
A Theoretical Analysis of the Coordination Modes of CuIIwith Penicillins: Activation of the β‐Lactam CN Bond
Authors: Campomanes Pablo , Menéndez M. Isabel , López Ramón , Sordo Tomás L.
Published: January 2005

The interaction of CuIIwith 6‐formylamino‐3α‐carboxypenam and 6‐acetylamino‐3α‐carboxypenam was investigated by means of DFT calculations with the UB3LYP functional. Nine different modes of complexation between CuIIand 6‐formylamino‐3α‐carboxypenam were located. When two water molecules directly bonded to CuIIare included in the calculations on 6‐acetylamino‐3α‐carboxypenam as penicillin model, only six CuII(H2O)2–6‐acetylamino‐3α‐carboxypenam complexes (1 S–6 S) are found. In solution the four most stable complexes obtained from our calculations,6 S,1 S,2 S, and3 S, exhibit CuIIin square‐planar coordination with at least one bond to the carboxylate group, in agreement with experimental evidence. Complexes6 S,1 S, and3 Swere previously suggested by available experimental evidence. In three of the most stable complexes (6 S,2 S, and3 S) the β‐lactam CN bond is remarkably activated and displays CN bond lengths similar to those found in some tetrahedral intermediates located for the hydrolysis of 2‐azetidinones. This suggests that these kinds of complexes belong to the reaction coordinate for the degradation ofβ‐lactam antibiotics in the presence of CuII.
Determining the Geometry of Hydrogen Bonds in Solids with Picometer Accuracy by Quantum‐Chemical Calculations and NMR Spectroscopy
Authors: Schulz‐Dobrick Martin , Metzroth Thorsten , Spiess Hans Wolfgang , Gauss Jürgen , Schnell Ingo
Published: January 2005

The structure of multiply hydrogen‐bonded systems is determined with picometer accuracy by a combined solid‐state NMR and quantum‐chemical approach. On the experimental side, advanced 1H15N dipolar recoupling NMR techniques are capable of providing proton–nitrogen distances of up to about 250 pm with an accuracy level of ±1 pm for short distances (i.e., around 100 pm) and ±5 pm for longer ones (i.e., 180 to 250 pm). The experiments were performed under fast magic‐angle spinning, which ensures sufficient dipolar decoupling and spectral resolution of the 1H resonance lines. On the quantum‐chemical side, the structures of the hydrogen‐bonded systems were computationally optimised, yielding complete sets of nitrogen–proton and proton–proton distances, which are essential for correctly interpreting the experimental NMR data. In this way, nitrogen–proton distances were determined with picometer accuracy, so that vibrational averaging effects on dipole–dipole couplings need to be considered. The obtained structures were finally confirmed by the complete agreement of computed and experimental 1H and 15N chemical shifts. This demonstrates that solid‐state NMR and quantum‐chemical methods ideally complement each other and, in a combined manner, represent a powerful approach for reliable, high‐precision structure determination whenever scattering techniques are inapplicable.
A method for the approximate synthesis of cellular non‐linear networks—Part 1: Circuit definition
Authors: Storace Marco , Repetto Lorenzo , Parodi Mauro
Published: January 2005

In this paper, we face the problem of the synthesis of cellular non‐linear networks (CNNs) able to find approximate solutions of either partial differential equations or functional minimization problems. In particular, the paper deals with the approximate synthesis of the multi‐terminal resistors that include all the non‐linearities of such dynamic circuits. The proposed approximation method is based on the piecewise‐linear (PWL) approach developed by Juliánet al. in the last few years, but it resorts to a different definition of the inner product and hence to other PWL basis functions. The method is applied to a case‐study concerning a CNN devoted to image processing. Copyright © 2003 John Wiley & Sons, Ltd.