bluuebunny/crossref_metadata_2025 huggingface dataset:
State-Space Dynamic Performance Preview-Predictive Controller
Authors: Ordys Andrzej W. , Tomizuka Masayoshi , Grimble Michael J.
Published: March 2007

The paper discusses state-space generalized predictive control and the preview control algorithms. The optimization procedure used in the derivation of predictive control algorithms is considered. The performance index associated with the generalized predictive controller (GPC) is examined and compared with the linear quadratic (LQ) optimal control formulation used in preview control. A new performance index and consequently a new algorithm is proposed dynamic performance predictive controller (DPPC) that combines the features of both GPC and preview controller. This algorithm minimizes the performance index through a dynamic optimization. A simple example illustrates the features of the three algorithms and prompts a discussion on what is actually minimized in predictive control. The DPPC algorithm, derived in this paper, provides for a minimum of the predictive performance index. The differences and similarities between the preview control and the predictive control have been discussed and optimization approach of predictive control has been explained.
Adaptive Control of Harmonic Drives
Authors: Zhu Wen-Hong , Dupuis Erick , Doyon Michel
Published: March 2007

Aimed at achieving ultrahigh control performance for high-end applications of harmonic drives, an adaptive control algorithm using additional sensing, namely, the joint and motor positions and the joint torque, and their practically available time derivatives, is proposed. The proposed adaptive controller compensates the large friction associated with harmonic drives, while incorporating the dynamics of flexspline. The L2∕L∞ stability and the L2 gain-induced H∞ stability are guaranteed in both joint torque and joint position control modes. Conditions for achieving asymptotic stability are also given. The proposed joint controller can be efficiently incorporated into any robot motion control system based on either its torque control interface or the virtual decomposition control approach. Experimental results demonstrated in both the time and frequency domains confirm the superior control performance achieved not only in individual joint motion, but also in coordinated motion of an entire robot manipulator.
Adaptive Input Shaping for Nonlinear Systems: A Case Study
Authors: Stergiopoulos John , Tzes Anthony
Published: March 2007

Input shaping is a technique that seeks to reduce residual vibrations of lightly damped systems through modification of the command input to the system. Although several input shaping techniques have been derived primarily from linear system theory, theoretical results are hard to be traced for their application to nonlinear systems. In most of the reported cases, a fixed shaper is designed based on the linearized version around an operating point of the nonlinear system. In this paper, an adaptive form of the input shaper is proposed for a class of nonlinear lightly damped systems. The adaptive shaper adjusts the magnitude and relative time difference between its impulses according to the instant frequency and damping of the linearized systems. The efficacy of the proposed scheme and its comparison to a fixed shaper is investigated through its application to a pendulum system. The adaptive shaper’s parameters vary according to the pendulum’s angle. The illustrative examples indicate the deficiencies of the fixed case and demonstrate the efficacy of the designed controller.
Parameter Identification for a High-Performance Hydrostatic Actuation System Using the Variable Structure Filter Concept
Authors: Habibi S. R. , Burton R.
Published: March 2007

Parameter estimation is an important concept that can be used for health and condition monitoring. Estimation or measurement of physically meaningful parameters and their evaluation against predetermined thresholds allows detection of gradual or abrupt deteriorations in the plant. This early detection of faults enables preventative unscheduled maintenance that is of benefit to industries concerned with reliability and safety. In this paper, a recently proposed state estimation strategy referred to as the smooth variable structure filter (SVSF) is reviewed and extended to parameter estimation. The SVSF is applied to a novel hydrostatic actuation system referred to as the electrohydraulic actuator (EHA). Condition monitoring of the EHA for preventative unscheduled maintenance would increase its safety in applications pertaining to aerospace and would reduce its operational and maintenance costs.
State Estimation With Finite Signal-to-Noise Models via Linear Matrix Inequalities
Authors: Li Weiwei , Skelton Robert E. , Todorov Emanuel
Published: March 2007

This paper presents estimation design methods for linear systems whose white noise sources have intensities affinely related to the variance of the signal they corrupt. Systems with such noise sources have been called finite signal-to-noise (FSN) models, and the results provided in prior work demonstrate that estimation problem for FSN systems (estimating to within a specified covariance error bound) is nonconvex. We shall show that a mild additional constraint for scaling will make the problem convex. In this paper, sufficient conditions for the existence of the state estimator are provided; these conditions are expressed in terms of linear matrix inequalities (LMIs), and the parametrization of all admissible solutions is provided. Finally, a LMI-based estimator design is formulated, and the performance of the estimator is examined by means of numerical examples.
An Instrumental Variable Method for Continuous-Time Transfer Function Model Identification With Application to Controller Auto-Tuning
Authors: Cunningham Patrick J. , Franchek Matthew A.
Published: March 2007

An instrumental variable algorithm is presented that estimates the coefficients of a continuous transfer function model directly from sampled data. The algorithm is based on instrumental variables extracted from an auxiliary model and input and output signal derivatives estimated by filtered difference equations. As a result, this method does not require any prior knowledge of the output noise. To ensure the validity of the filtered derivative estimates, a criterion based on the Nyquist frequency and the system bandwidth is established. Then the concept of asymptotic consistency is applied to the proposed instrumental variable algorithm to identify the conditions for convergence of the model parameter estimates. Specifically, the asymptotic consistency conditions impose a continuous and persistent exciting constraint on the input signal. This is analogous to the persistent excitation condition for identification of discrete models. The proposed instrumental variable algorithm is demonstrated within an auto-tuning algorithm for feedback controllers based on plant inversion. In this application, the algorithm is only suitable for lower-order transfer functions that are minimum-phase and stable. These types of systems are common in industrial applications for manufacturing and process control. Here, the algorithm is experimentally validated for automatic tuning of the idle speed controller on a 4.6L Ford V-8 spark ignition engine.
Optimal Performance of Variable Stiffness Devices for Structural Control
Authors: Leavitt John , Jabbari Faryar , Bobrow James E.
Published: March 2007

This paper addresses control of structural vibrations using semi-active actuators that are capable of manipulating stiffness and∕or producing variable stiffness. Usually vibration suppression is achieved using damping devices rather than stiffness ones. However, stiffness devices can produce large forces and have significant advantages for shock isolation purposes. In this work we use a passivity approach to establish the requirements for the control law for a structure equipped with semi-active stiffness devices. We also solve an optimal control problem that demonstrates that our passive, resetting feedback control law approximates the optimal control. Simulation and experimental results are presented in support of the proposed approach.
The Genome of Black Cottonwood,
Populus trichocarpa
(Torr. & Gray)
Authors: Tuskan G. A. , DiFazio S. , Jansson S. , Bohlmann J. , Grigoriev I. , Hellsten U. , Putnam N. , Ralph S. , Rombauts S. , Salamov A. , Schein J. , Sterck L. , Aerts A. , Bhalerao R. R. , Bhalerao R. P. , Blaudez D. , Boerjan W. , Brun A. , Brunner A. , Busov V. , Campbell M. , Carlson J. , Chalot M. , Chapman J. , Chen G.-L. , Cooper D. , Coutinho P. M. , Couturier J. , Covert S. , Cronk Q. , Cunningham R. , Davis J. , Degroeve S. , Déjardin A. , dePamphilis C. , Detter J. , Dirks B. , Dubchak I. , Duplessis S. , Ehlting J. , Ellis B. , Gendler K. , Goodstein D. , Gribskov M. , Grimwood J. , Groover A. , Gunter L. , Hamberger B. , Heinze B. , Helariutta Y. , Henrissat B. , Holligan D. , Holt R. , Huang W. , Islam-Faridi N. , Jones S. , Jones-Rhoades M. , Jorgensen R. , Joshi C. , Kangasjärvi J. , Karlsson J. , Kelleher C. , Kirkpatrick R. , Kirst M. , Kohler A. , Kalluri U. , Larimer F. , Leebens-Mack J. , Leplé J.-C. , Locascio P. , Lou Y. , Lucas S. , Martin F. , Montanini B. , Napoli C. , Nelson D. R. , Nelson C. , Nieminen K. , Nilsson O. , Pereda V. , Peter G. , Philippe R. , Pilate G. , Poliakov A. , Razumovskaya J. , Richardson P. , Rinaldi C. , Ritland K. , Rouzé P. , Ryaboy D. , Schmutz J. , Schrader J. , Segerman B. , Shin H. , Siddiqui A. , Sterky F. , Terry A. , Tsai C.-J. , Uberbacher E. , Unneberg P. , Vahala J. , Wall K. , Wessler S. , Yang G. , Yin T. , Douglas C. , Marra M. , Sandberg G. , Van de Peer Y. , Rokhsar D.
Published: March 2007

We report the draft genome of the black cottonwood tree,
Populus trichocarpa
. Integration of shotgun sequence assembly with genetic mapping enabled chromosome-scale reconstruction of the genome. More than 45,000 putative protein-coding genes were identified. Analysis of the assembled genome revealed a whole-genome duplication event; about 8000 pairs of duplicated genes from that event survived in the
Populus
genome. A second, older duplication event is indistinguishably coincident with the divergence of the
Populus
and
Arabidopsis
lineages. Nucleotide substitution, tandem gene duplication, and gross chromosomal rearrangement appear to proceed substantially more slowly in
Populus
than in
Arabidopsis. Populus
has more protein-coding genes than
Arabidopsis
, ranging on average from 1.4 to 1.6 putative
Populus
homologs for each
Arabidopsis
gene. However, the relative frequency of protein domains in the two genomes is similar. Overrepresented exceptions in
Populus
include genes associated with lignocellulosic wall biosynthesis, meristem development, disease resistance, and metabolite transport.
The Dynamic Energy Landscape of Dihydrofolate Reductase Catalysis
Authors: Boehr David D. , McElheny Dan , Dyson H. Jane , Wright Peter E.
Published: March 2007

We used nuclear magnetic resonance relaxation dispersion to characterize higher energy conformational substates of
Escherichia coli
dihydrofolate reductase. Each intermediate in the catalytic cycle samples low-lying excited states whose conformations resemble the ground-state structures of preceding and following intermediates. Substrate and cofactor exchange occurs through these excited substates. The maximum hydride transfer and steady-state turnover rates are governed by the dynamics of transitions between ground and excited states of the intermediates. Thus, the modulation of the energy landscape by the bound ligands funnels the enzyme through its reaction cycle along a preferred kinetic path.
Through Art to Association in Japanese Politics
Authors: Turner Christena
Published: March 2007

Bonds of Civility
. Aesthetic Networks and the Political Origins of Japanese Culture.
By Eiko Ikegami
. Cambridge University Press, New York, 2005. 475 pp. $80, £45. ISBN 0-521-80942-8. Paper, $36.99, £20.99. ISBN 0-521-60115-0.

The author explores the interrelations between the culture and politics in medieval and early modern Japan.
Caveolin-1 Is Essential for Liver Regeneration
Authors: Fernández Manuel A. , Albor Cecilia , Ingelmo-Torres Mercedes , Nixon Susan J. , Ferguson Charles , Kurzchalia Teymuras , Tebar Francesc , Enrich Carlos , Parton Robert G. , Pol Albert
Published: March 2007

Liver regeneration is an orchestrated cellular response that coordinates cell activation, lipid metabolism, and cell division. We found that
caveolin-1
gene–disrupted mice (
cav1
–/–
mice) exhibited impaired liver regeneration and low survival after a partial hepatectomy. Hepatocytes showed dramatically reduced lipid droplet accumulation and did not advance through the cell division cycle. Treatment of
cav1
–/–
mice with glucose (which is a predominant energy substrate when compared to lipids) drastically increased survival and reestablished progression of the cell cycle. Thus, caveolin-1 plays a crucial role in the mechanisms that coordinate lipid metabolism with the proliferative response occurring in the liver after cellular injury.
Near-Field Microscopy Through a SiC Superlens
Authors: Taubner Thomas , Korobkin Dmitriy , Urzhumov Yaroslav , Shvets Gennady , Hillenbrand Rainer
Published: March 2007

The wave nature of light limits the spatial resolution in classical microscopy to about half of the illumination wavelength. Recently, a new approach capable of achieving subwavelength spatial resolution, called superlensing, was invented, challenging the already established method of scanning near-field optical microscopy (SNOM). We combine the advantages of both techniques and demonstrate a novel imaging system where the objects no longer need to be in close proxim-ity to a near-field probe, allowing for optical near-field microscopy of subsurface objects at sub-wavelength-scale lateral resolution.
Oldest Writing in the New World
Authors: del Carmen Rodríguez Martínez Ma. , Ceballos Ponciano Ortíz , Coe Michael D. , Diehl Richard A. , Houston Stephen D. , Taube Karl A. , Calderón Alfredo Delgado
Published: March 2007

A block with a hitherto unknown system of writing has been found in the Olmec heartland of Veracruz, Mexico. Stylistic and other dating of the block places it in the early first millennium before the common era, the oldest writing in the New World, with features that firmly assign this pivotal development to the Olmec civilization of Mesoamerica.
Comment on "Large-Scale Sequence Analysis of Avian Influenza Isolates"
Authors: Holmes Edward C. , Lipman David J. , Zamarin Dmitriy , Yewdell Jonathan W.
Published: March 2007

Obenauer
et al
. (Research Articles, 17 March 2006, p. 1576) reported that the influenza A virus PB1-F2 gene is evolving under strong positive selection, as documented by an extremely high ratio of the number of nonsynonymous nucleotide substitutions to the number of synonymous substitutions (dN/dS). However, we show that this observation is likely to be an artifact related to the location of PB1-F2 in the +1 reading frame of the PB1 gene.
Epstein-Barr Virus BGLF4 Kinase Induces Premature Chromosome Condensation through Activation of Condensin and Topoisomerase II
Authors: Lee Chung-Pei , Chen Jen-Yang , Wang Jiin-Tarng , Kimura Keiji , Takemoto Ai , Lu Chih-Chung , Chen Mei-Ru
Published: March 2007

Previous studies of Epstein-Barr virus (EBV) replication focused mainly on the viral and cellular factors involved in replication compartment assembly and controlling the cell cycle. However, little is known about how EBV reorganizes nuclear architecture and the chromatin territories. In EBV-positive nasopharyngeal carcinoma NA cells or Akata cells, we noticed that cellular chromatin becomes highly condensed upon EBV reactivation. In searching for the possible mechanisms involved, we found that transient expression of EBV BGLF4 kinase induces unscheduled chromosome condensation, nuclear lamina disassembly, and stress fiber rearrangements, independently of cellular DNA replication and Cdc2 activity. BGLF4 interacts with condensin complexes, the major components in mitotic chromosome assembly, and induces condensin phosphorylation at Cdc2 consensus motifs. BGLF4 also stimulates the decatenation activity of topoisomerase II, suggesting that it may induce chromosome condensation through condensin and topoisomerase II activation. The ability to induce chromosome condensation is conserved in another gammaherpesvirus kinase, murine herpesvirus 68 ORF36. Together, these findings suggest a novel mechanism by which gammaherpesvirus kinases may induce multiple premature mitotic events to provide more extrachromosomal space for viral DNA replication and successful egress of nucleocapsid from the nucleus.
Pressure–temperature–deformation paths of closely associated ultra-high-pressure (diamond-bearing) crustal and mantle rocks of the Kimi complex: implications for the tectonic history of the Rhodope Mountains, northern Greece
Authors: Mposkos E , Krohe A
Published: March 2007

The ultra-high-pressure (UHP) Kimi complex (uppermost eastern Rhodope Mountains) is a tectonic mixture of crustal and mantle derived associations. Pressure–temperature (P–T) paths and microtextural and geochronological data reveal that crustal and mantle parts juxtaposed against each other at a depth corresponding to ~15 kbar (1 kbar = 100 MPa) had separate ascend histories. The crustal rocks comprise amphibolitised eclogites, orthogneisses, marbles, and migmatitic pelitic gneisses. The latter document UHP metamorphism within the dehydration-melting range of pelitic gneisses, with maximum P–T conditions of >45 kbar at ~1000 °C, as determined by diamond inclusions in garnet and rutile needle exsolutions in Na-bearing garnet. Decompression was combined with only little cooling before 15 kbar, followed by more significant cooling between 15 and 10 kbar. This P–T path probably reflects ascent of UHP rocks within a subduction channel, followed by accretion in the lower crust of a thickened wedge. Although the first ascend phase was probably rapid, the overall time span for UHP metamorphism and final exhumation may have extended over more than 70 Ma. A U–Pb sensitive high-resolution ion microprobe (SHRIMP) age on zircons of ±149 Ma was suggested to date the UHP metamorphism, whereas Rb–Sr white mica and U–Pb zircon ages from syn-shearing pegmatites of ±65 Ma constrain medium- to low-grade shearing and final exhumation of UHP rocks. Mantle parts consisting of spinel–garnet metaperidotites and garnet pyroxenites reached maximum P–T conditions in the garnet-peridotite field at T > 1200 °C and P > 25 kbar. This was associated with plastic flow and followed by severe near isothermal cooling to T < 800 °C at 15 kbar and static annealing. A garnet–clinopyroxene whole-rock Sm–Nd age from a garnet pyroxenite of ±119 Ma probably reflects the age of metamorphic mantle processes (static annealing following the high P/high T strain episode), rather than constraining the age of UHP metamorphism.
Modular syntheses of oxazolinylamine ligands and characterization of group 10 metal complexes
Authors: Caputo Christine A , Carneiro Florentino d S , Jennings Michael C , Jones Nathan D
Published: March 2007

The syntheses of aminoalkyloxazoline and pyrrolidinyloxazoline ligands, each of which bear a pair of chiral centres, by both known and new routes are reported. Variable temperature NMR studies show that the known stepwise syntheses of the pyrrolidinyl compounds are not complicated by epimerization; however, coordination of one of the aminoalkyl derivatives to Pt(II) under conditions of prolonged heating to 80 °C does give mixtures of diastereomeric N,N ′-chelated complexes that result from inversion of the chiral centre associated with the aminoalkyl fragment. A new synthesis of pyrrolidinyloxazoline ligands that involves the Zn-catalyzed cyclization of Cbz-protected 2-cyanopyrrolidine and β-amino alcohols is also reported. This procedure offers the advantages of economy, shorter time, and fewer purification steps over the previously reported synthesis. In addition, the crystal structure of an enantiopure Pd(II) complex of an N,N ′-chelated pyrrolidinyloxazoline is disclosed. This compound has a pseudo-C2 axis of symmetry, which may make it suitable for asymmetric catalytic applications.Key words: chiral ligands, ligand design, oxazolines, variable temperature NMR spectroscopy, asymmetric catalysis, coordination compounds, palladium, platinum
Impaired insulin secretion in a mouse model of ataxia telangiectasia
Authors: Miles Philip D. , Treuner Kai , Latronica Marc , Olefsky Jerrold M. , Barlow Carrolee
Published: March 2007

Ataxia telangiectasia (A-T) is an autosomal recessive disease caused by mutations in the A-T mutated (ATM) gene. The gene encodes a serine/threonine kinase with important roles in the cellular response to DNA damage, including the activation of cell cycle checkpoints and induction of apoptosis. Although these functions might explain the cancer predisposition of A-T patients, the molecular mechanisms leading to glucose intolerance and diabetes mellitus (DM) are unknown. We have investigated the pathogenesis of DM in a mouse model of A-T. Here we show that young Atm-deficient mice show normal fasting glucose levels and normal insulin sensitivity. However, oral glucose tolerance testing revealed delayed insulin secretion and resulting transient hyperglycemia. Aged Atm−/− mice show a pronounced increase in blood glucose levels and a decrease in insulin and C-peptide levels. Our findings support a role for ATM in metabolic function and point toward impaired insulin secretion as the primary cause of DM in A-T.
The major facilitator superfamily member Slc37a2 is a novel macrophage- specific gene selectively expressed in obese white adipose tissue
Authors: Kim Ji Young , Tillison Kristin , Zhou Shengli , Wu Yu , Smas Cynthia M.
Published: March 2007

A marked degree of macrophage infiltration of white adipose tissue (WAT) occurs in obesity and may link excess adiposity with the chronic inflammatory state underlying metabolic syndrome and other comorbidities of obesity. Excess deposition of fat in the intra-abdominal vs. subcutaneous WAT depots is a key component of metabolic syndrome. Through construction and differential screening of a murine ob/ob WAT cDNA library, we identified Slc37a2, a novel sugar transporter of the major facilitator superfamily, to be twofold enriched in intra-abdominal vs. subcutaneous fat. We find Slc37a2 is a macrophage-enriched transcript. In murine tissues, Slc37a2 transcript is restricted to spleen, thymus, and obese WAT. It is also readily detected in the RAW264.7 macrophage cell line and increases 46-fold during macrophage differentiation of THP-1 human monocytes. Compared with wild-type mice, Slc37a2 transcript is increased epididymal ninefold in ob/ob WAT and assessment of expression of the macrophage marker emr1 indicated upregulation of Slc37a2 transcript in macrophages populating ob/ob WAT. Studies with PNGase F and tunicamycin reveal the Slc37a2 protein is posttranslationally modified by addition of N-linked glycans. Slc37a2 protein migrates as heterogeneous species of ∼50–75 kDa and its ectopic expression in mammalian cells results in the appearance of large intracellular vacuoles. We postulate that the function of this macrophage-specific putative sugar transporter is central to the metabolism of the macrophage population specifically present in obese WAT.
Globular adiponectin resistance develops independently of impaired insulin-stimulated glucose transport in soleus muscle from high-fat-fed rats
Authors: Mullen Kerry L. , Smith Angela C. , Junkin Kathryn A. , Dyck David J.
Published: March 2007

High-fat (HF) diets induce insulin resistance and alter lipid metabolism, although controversy exists regarding the impact of saturated vs. polyunsaturated fats. Adiponectin (Ad) stimulates fatty acid (FA) oxidation and improves insulin sensitivity in humans and rodents, due in part to the activation of AMP-activated protein kinase (AMPK) and subsequent deactivation of acetyl coenzyme A carboxylase (ACC). In genetically obese, diabetic mice, this acute stimulatory effect on AMPK in muscle is lost. The ability of a HF diet to induce skeletal muscle Ad resistance has not been examined. The purpose of this study was to determine whether Ad's effects on FA oxidation and AMPK/ACC would be reduced following different HF diets, and if this coincided with the development of impaired maximal insulin-stimulated glucose transport. Rats were fed a control (10% kcal fat, CON), high unsaturated fat (60% kcal safflower oil, SAFF), or high saturated fat diet (60% kcal lard, LARD) for 4 wk. Following the dietary intervention, glucose transport, lipid metabolism, and AMPK/ACC phosphorylation were measured in the presence and absence of globular Ad (gAd, 2.5 μg/ml) in isolated soleus muscle. LARD rats showed reduced rates of maximal insulin-stimulated glucose transport compared with CON and SAFF (+68 vs. +172 and +184%, P ≤ 0.001). gAd increased pACC (+25%, P ≤ 0.01) and FA oxidation (+28%, P ≤ 0.05) in CON rats, but not in either HF group. Thus 4 wk of HF feeding results in the loss of gAd stimulatory effect on ACC phosphorylation and muscle FA oxidation, and this can occur independently of impaired maximal insulin-stimulated glucose transport.
S1P modulator FTY720 limits matrix expansion in acute anti-thy1 mesangioproliferative glomerulonephritis
Authors: Martini Sebastian , Krämer Stephanie , Loof Tanja , Wang-Rosenke Yingrui , Daig Ute , Budde Klemens , Neumayer Hans-H. , Peters Harm
Published: March 2007

FTY720 is a novel immune modulator whose primary action is blood lymphocyte depletion through interaction with sphingosine-1-phosphate (S1P) receptors. The present study analyzes the effect of FTY720 on both the early mesangial cell injury and the subsequent matrix expansion phase of experimental mesangioproliferative glomerulonephritis. Disease was induced by injection of OX-7 anti-thy1 antibody into male Wistar rats. In both protocols, FTY720 administration (0.3 mg/kg body wt) resulted in a selective and very marked reduction in blood lymphocyte count. In the injury experiment, the S1P receptor modulator was given starting 5 days before and continued until 1 day after antibody injection. FTY720 did not significantly affect the degree of anti-thy1-induced mesangial cell lysis and glomerular-inducible nitric oxide production. In the matrix expansion experiment, FTY720 treatment was started 1 day after antibody injection and continued until day 7. In this protocol, the S1P modulator reduced proteinuria, histological matrix expansion, and glomerular protein expression of TGF-β1, fibronectin, and PAI-1. Glomerular collagen III staining intensity was decreased. FTY720 reduced markedly glomerular lymphocyte number per cross section and to a lesser degree macrophage infiltration. In conclusion, FTY720 significantly limits TGF-β1 overexpression and matrix protein expression following induction of acute anti-thy glomerulonephritis, involving reductions in blood and glomerular lymphocyte numbers. The results suggest that lymphocytes actively contribute to matrix expansion in experimental mesangioproliferative glomerulonephritis. Our study expands on findings on FTY720's beneficial effects on tubulointerstitial and functional disease progression previously reported in anti-thy1-induced chronic glomerulosclerosis.
Topographic Maps in Human Frontal Cortex Revealed in Memory-Guided Saccade and Spatial Working-Memory Tasks
Authors: Kastner Sabine , DeSimone Kevin , Konen Christina S. , Szczepanski Sara M. , Weiner Kevin S. , Schneider Keith A.
Published: March 2007

We used fMRI at 3 Tesla and improved spatial resolution (2 × 2 × 2 mm3) to investigate topographic organization in human frontal cortex using memory-guided response tasks performed at 8 or 12 peripheral locations arranged clockwise around a central fixation point. The tasks required the location of a peripheral target to be remembered for several seconds after which the subjects either made a saccade to the remembered location (memory-guided saccade task) or judged whether a test stimulus appeared in the same or a slightly different location by button press (spatial working-memory task). With these tasks, we found two topographic maps in each hemisphere, one in the superior branch of precentral cortex and caudalmost part of the superior frontal sulcus, in the region of the human frontal eye field, and a second in the inferior branch of precentral cortex and caudalmost part of the inferior frontal sulcus, both of which greatly overlapped with activations evoked by visually guided saccades. In each map, activated voxels coded for saccade directions and memorized locations predominantly in the contralateral hemifield with neighboring saccade directions and memorized locations represented in adjacent locations of the map. Particular saccade directions or memorized locations were often represented in multiple locations of the map. The topographic activation patterns showed individual variability from subject to subject but were reproducible within subjects. Notably, only saccade-related activation, but no topographic organization, was found in the region of the human supplementary eye field in dorsomedial prefrontal cortex. Together these results show that topographic organization can be revealed outside sensory cortical areas using more complex behavioral tasks.
Quantitative genetic basis of arterial phenotypes in the Brown Norway rat
Authors: Kota Lalitha , Osborne-Pellegrin Mary , Schulz Herbert , Behmoaras Jacques , Coutard Michèle , Gong Maolian , Hübner Norbert
Published: March 2007

The Brown Norway (BN) rat presents several genetically determined arterial phenotypes of interest, i.e., ruptures of the internal elastic lamina (RIEL) in the abdominal aorta (AA), iliac (IAs), and renal arteries, aortic elastin deficit and higher frequency of persistent ductus arteriosus (PDA) than other strains. We investigated the genetic basis of these phenotypes. We established a backcross between BN and the LOU reference strain and performed a genome-wide scan on 104 males and 105 females with 193 microsatellite markers followed by linkage analysis. RIEL in AA and IAs showed highly significant linkage to a locus on chromosome 5 and suggestive linkage to a locus on chromosome 10, which is syntenic to one linked to a syndrome of thoracic aortic aneurysms with PDA in humans. In contrast, renal artery RIEL mapped to a chromosome 3 locus and thoracic aortic elastic content to two loci on chromosome 2. PDA was significantly linked to two different quantitative trait loci (QTL) on chromosomes 8 and 9. This is the first study in rats to identify genetic loci for PDA. We identified 21 candidate genes by functional relevance or integration of our mapping data with global expression analysis. Sequencing these genes identified 47 single nucleotide polymorphisms, but no functionally relevant amino acid changes. By expression analysis, myosin heavy chain 10, nonmuscle, in the chromosome 10 QTL, emerged as a candidate for RIEL in AA and IAs. Furthermore, production of a congenic line for the chromosome 5 QTL proved implication of this locus in RIEL formation.
Comprehensive QTL analysis of serum cholesterol levels before and after a high-cholesterol diet in SHRSP
Authors: Mashimo Tomoji , Ogawa Hiroshi , Cui Zong-Hu , Harada Yuji , Kawakami Kohei , Masuda Junichi , Yamori Yukio , Nabika Toru
Published: March 2007

The stroke-prone spontaneously hypertensive rat (SHRSP) showed an exaggerated response to a high-fat, high-cholesterol (HFC) diet, and the resulting reactive hypercholesterolemia was suggested to exacerbate the atherogenic process in this rat. We thus performed a quantitative trait locus (QTL) analysis on the serum cholesterol level of SHRSP before and after the HFC diet, with the final goal being the identification of the genetic mechanisms of its reactive hypercholesterolemia. Three hundred fifty-eight F2 rats between SHRSP and Wistar-Kyoto rat were employed in the study. The serum cholesterol and apoprotein E were measured before and after 2 wk of feeding with the HFC diet. Multiple QTLs for the basal cholesterol level were identified on chromosomes 1 and 5, whereas those for the postdietary cholesterol level were on chromosomes 7, 15, and 16. The cholesterol QTLs before and after HFC diet did not overlap with one another, implying that the involved metabolic processes were considerably different between the two conditions. Supporting this, VLDL and LDL cholesterol were the major components of the postdietary serum cholesterol, whereas the basal cholesterol level consisted mainly of HDL cholesterol. A substantial difference of the QTLs between males and females was observed, especially after the HFC diet. The QTL on chromosome 15 had an inverse effect on the cholesterol level, suggesting that the congenic substitution of the SHRSP fragment with that of Wistar-Kyoto rats could induce a greater cholesterol level in SHRSP. This observation is significant in establishing a new model for atherosclerosis with hypertension in rats.
Temporal analysis of E2 transcriptional induction of PTP and MKP and downregulation of IGF-I pathway key components in the mouse uterus
Authors: Ivanga Mahinè , Labrie Yvan , Calvo Ezequiel , Belleau Pascal , Martel Céline , Luu-The Van , Morissette Jean , Labrie Fernand , Durocher Francine
Published: March 2007

17β-Estradiol (E2) is well known to be associated with uterine cancer, endometriosis, and leiomyomas. Although insulin-like growth factor I (IGF-I) has been identified as a mediator of the uterotrophic effect of E2 in several studies, this mechanism is still not well understood. In the present study, identification of the genes modulated by a physiological dose of E2, in the uterus, has been done in ovariectomized mice using Affymetrix microarrays. The E2-induced genomic profile shows that multiple genes belonging to the IGF-I pathway are affected after exposure to E2. Two phases of regulation could be identified. First, from 0 to 6 h, the expression of genes involved in the cell cycle, growth factors, protein tyrosine phosphatases, and MAPK phosphatases is quickly upregulated by E2, while IGF-I receptor and several genes of the MAPK and phosphatidylinositol 3-kinase pathways are downregulated. Later, i.e., from 6 to 24 h, transporters and peptidases/proteases are stimulated, whereas defense-related genes are differentially regulated by E2. Finally, cytoarchitectural genes are modulated later. The present data show that a physiological dose of E2 induces, within 24 h, a series of transcriptional events that promote the uterotrophic effect. Among these, the E2-mediated activation of the IGF-I pathway seems to play a pivotal role in the uterotrophic effect. Furthermore, the protein tyrosine phosphatases and MAPK phosphatases are likely to modulate the estrogenic uterotrophic action by targeting, at different steps, the IGF-I pathway.
Optical Coherence Tomography for Artwork Diagnostics
Authors: Targowski Piotr , Góra Michalina , Wojtkowski Maciej
Published: March 2007

An overview of the optical coherence tomography (OCT) technique is given. Time domain, spectral and sweep source modalities are briefly described, and important physical parameters of the OCT instrument are discussed. Examples of the application of OCT to diagnosis of various art objects such as oil paintings on canvas (imaging of glaze and varnish layers), porcelain, faience, and parchment are presented. Applications to surface profilometry of painting on canvas are also discussed.
Preliminary Laser Cleaning Studies of a Consolidated Prehistoric Basketry Coming from the Pile Building of Fiavè-Carera in the North-East of Italy
Authors: Belli Romina , Miotello Antonio , Mosaner Paolo , Toniutti Laura , Bazzanella Marta
Published: March 2007

In the archaeological field, some specific advantages are recognized to laser cleaning, like, for example, the absence of mechanical contacts with the sample. The cleaning procedures generally involve a multilayer structure (dust, dirty, organic deposits, and, in some cases, consolidant substances). In this work, prehistoric wood samples (found and consolidated in 1970s) have been laser irradiated (KrF excimer laser) in order to restore their original surface aspect. A certain amount of burned matter was also present.
Samples came from a fragment of a prehistoric basketry found in the lake dwelling site of Fiavè-Carera, Trento, Italy (1500–1400 BC). It was observed that the laser cleaning effects are strictly dependent on the irradiation parameters (power density and number of pulses). Efficient material removal was possible by using appropriate energy density. Moreover, for lower laser energy density, special structures appeared on the surface of the consolidating substance that we attributed to heating-induced stresses
on the consolidant surface.
Optical Coherence Tomography for Examination of Parchment Degradation
Authors: Góra Michalina , Pircher Michael , Götzinger Erich , Bajraszewski Tomasz , Strlic Matija , Kolar Jana , Hitzenberger Christoph K. , Targowski Piotr
Published: March 2007

A novel application of Optical Coherence Tomography utilizing infrared light of 830 nm central wavelength for non invasive examination of the structure of parchment, some covered with iron gall ink, is presented. It is shown that both the parchment and the ink applied are sufficiently transparent to light of this wavelength. In the study, Spectral OCT (SOCT) as well as Polarisation Sensitive OCT (PS-OCT) techniques were used to obtain cross-sectional images of samples of parchment based on scattering properties. The second technique was additionally employed to recover the birefringence properties and the optical axis orientations of the sample. It was shown that freshly produced parchment exhibits a degree of birefringence. However, this property declines with ageing, and samples of old parchment completely depolarise the incident light.
Laser Cleaning Tests on Archaeological Copper Alloys Using an ND:YAG Laser
Authors: Korenberg Capucine , Baldwin Alexandra
Published: March 2007

Laser cleaning tests were performed on five archaeological copper alloy objects using a Q-switched Nd:YAG laser at 1064 nm. As a comparison, a section of each object was cleaned mechanically. Prior to cleaning, cross-sections were prepared to characterise the corrosion crust and help to locate the position of the original surface. Laser cleaning was not successful at removing burial deposits on two of the objects. For the other three objects, the laser removed most of the corrosion crust. This was not always satisfactory, as cleaning was sometimes accompanied by the loss of the original surface. In addition, laser-cleaned surfaces were matt compared to mechanically cleaned surfaces. In some instances, the former had a disfiguring purple hue which was attributed to the formation of particles that could be seen when examining the surface using scanning electron microscopy. For all the objects examined here, superior results were obtained by mechanical cleaning.
Characterization of Stone Cleaning by Nd:YAG Lasers with Different Pulse Duration
Authors: Bartoli Laura , Pouli Paraskevi , Fotakis Costas , Siano Salvatore , Salimbeni Renzo
Published: March 2007

The present work is a comparative study on the laser cleaning of stonework using Nd:YAG lasers at different pulse durations. The ablation rate, the degree of cleaning, and the appearance of the treated surface were studied irradiating a simulated sample and a real stone artefact using three different Nd:YAG laser systems with pulse duration of 90 microseconds, 15 nanoseconds, and 150 picoseconds. To our knowledge, the picosecond laser is here used for the first time in stone conservation. Differences in efficiency and in cleaning result are shown and discussed.
Assisted Interpretation of Laser-Induced Fluorescence Spectra of Egg-Based Binding Media Using Total Emission Fluorescence Spectroscopy
Authors: Nevin Austin , Anglos Demetrios
Published: March 2007

Laser-induced fluorescence (LIF) spectroscopy can provide nondestructive, qualitative analysis of protein-based binding media found in artworks. Fluorescence emissions from proteins in egg yolk and egg white are due to autofluorescent aromatic amino acids as well as other native and age-related fluorophores, but the potential of fluorescence spectroscopy for the differentiation between binding media is dependent on the choice of a suitable excitation wavelength and limited by problems in interpretation. However, a better understanding of emission spectra associated with LIF can be achieved following comparisons with total emission fluorescence spectra where a series of consecutive emission spectra are recorded over a specific range. Results using nanosecond UV laser sources for LIF of egg-based binding media are presented which are rationalised following comparisons with total emission spectra. Specifically, fluorescence is assigned to tryptophan and oxidation products of amino acids; in the case of egg yolk, fatty-acid polymerisation and age-related degradation products account for the formation of fluorophores.
Laser Cleaning of Easel Paintings: An Overview
Authors: Bordalo Rui , Morais Paulo J. , Gouveia Helena , Young Christina
Published: March 2007

The application of laser cleaning to paintings is relatively recent despite its use on stone-based materials for over 30 years. The cleaning of paintings is of high importance, because it is the least reversible invasive intervention, as well as the most usual of all conservation treatments. Paintings are multilayer system of heterogeneous nature, often very sensitive and inherent difficult to clean. Being a noncontact method, laser cleaning has advantages compared to alternative techniques. Over the last decade, there have been important research studies and advances. However, they are far from sufficient to study the effects on painting materials and to establish the best parameters for each material under investigation. This paper presents a historical overview of the application of laser technology to the cleaning of paintings giving special emphasis on the research of the last decade. An overview of the current research into the interaction between the radiation and the different painting materials (varnish, pigments, and medium) is also given. The pigment's mechanisms of discoloration and the presence of media as a variable factor in the discoloration of pigments are discussed.
Optical Coherence Tomography for Tracking Canvas Deformation
Authors: Targowski Piotr , Góra Michalina , Bajraszewski Tomasz , Szkulmowski Maciej , Rouba Bogumiła , Łękawa-Wysłouch Teresa , Tymińska-Widmer Ludmiła
Published: March 2007

Preliminary results of the application of optical coherence tomography (OCT), in particular in its spectral mode (SOCT), to tracking of deformations in paintings on canvas caused by periodical humidity changes are presented. The setup is able to monitor the position of a chosen point at the surface of a painting with micrometre precision, simultaneously in three dimensions, every 100 seconds. This allows recording of deformations associated with crack formation. For the particular painting model examined, it was shown that the surface moves in-plane towards the corner, and bulges outwards (Z-direction) in response to a rise in humidity. Subsequent to the first humidification/drying cycle, translation in the Z-direction is decreased, whilst in-plane translations increase somewhat. It was also shown that the response of the painting on canvas begins immediately on changing the relative humidity in the surroundings.
“Single Shot” Laser Multiphoton Ionization Detection of UF5 Followingthe 266 nm Photodissociation of UF6
Authors: Chou J. S. , Sumida D. , Stuke M. , Wittig C.
Published: March 2007

By using laser multiphoton ionization and a time‐of‐flight mass filter, we have detected
nascent UF5 from the 266 nm laser photodissociation of UF6, following a single laser firing.
The method can be used to monitor these species under conditions wherein isotopically selective excitation is responsible for the dissociation of UF6.
Different Responses of Proliferating and Resting Tumor HeLa Cells to Pulsed High Repetition Rate Low‐Intensity Laser Light at 271 nm
Authors: Karu T. I. , Kalendo G. S. , Letokhov V. S. , Lobko V. V.
Published: March 2007

The action of pulsed high repetition rate UV laser radiation (2‐nd harmonic of Cu vapor
laser, λ = 271 nm, pulse duration 18 nsec, repetition rate 10 kHz) on proliferating and
resting HeLa cells has been studied. The intensity of DNA synthesis changes after such kinds
of irradiation for both types of cells. For proliferating cells DNA synthesis is suppressed,
while for the resting ones stimulation is observed in the dose range from 0.05 to 5 J/m2.
Spectral and Temperature Dependence of Laser Induced Dissociative Attachment in SF6
Authors: Barbe R. , Astruc J.-P. , Lagreze A. , Schermann J.-P.
Published: March 2007

We consider the influence of resonant laser excitation upon the dissociative reaction between
SF6 molecules and very low energy electrons. Experimentally, the use of valence electrons
of atoms in Rydberg states ensures a well‐defined energy resolution of the scattering electrons
in the crossed beam apparatus. A spectroscopic model of the infrared absorption of CO2 laser
radiation by SF6 gives a fair determination of the energy levels and vibrational transitions
involved in the dissociative process. This reaction between highly excited atoms and a
molecule is interpreted as a three step process: attachment of a quasi‐free electron, followed
by the interaction between the atomic ionic core and the negative molecular ion leading to
a partial stabilization and, finally, the competition between the dissociating and the autodetachment
channels.
New Continuous Laser Emissions in Te	2
Authors: Topouzkhanian A. , Wellegehausen B. , Effantin C. , d′Incan J. , Verges J.
Published: March 2007

New continuous laser emissions of different Te2 isotopes on many lines in the spectral range of 4600 Å to 7800 Å have been obtained upon excitation with the 4067 Å and 4131 Å lines of a krypton ion laser. Thresholds of several mW and output efficiencies of 5% have been achieved. By means of Fourier transform spectrometry accurate fluorescence wavenumbers have been determined, leading to an exact assignment of the observed laser lines.
Sputtering of Neutral Molecules and Molecular Ions From the Adenine Crystal Surface Induced by the UV Picosecond Laser Pulse
Authors: Antonov V. S. , Letokhov V. S. , Matveyets Yu. A. , Shibanov A. N.
Published: March 2007

This paper presents the results of observation of sputtering of neutral molecules and ions
from the crystal adenine surface induced by fourth‐harmonic Nd:YAG laser radiation with a
pulse duration of 30 ps. The energy fluence of laser pulses was in the region (1–3) × 10−4
J/cm2. The kinetic energy distribution of the sputtered molecules spreads up to 0.7 eV. The
experiment shows that the threshold of adenine molecular ion sputtering is connected with
absorbed energy density in upper layers of the crystal surface but not by laser radiation
intensity.
Electronic Relaxation and Oxygen Recombination Processes in Photodissociated Oxyhemoglobin After Picosecond Flash Photolysis
Authors: Valat P. , Tourbez H. , Alpert B.
Published: March 2007

Oxyhemoglobin photolysis has been investigated with picosecond laser techniques. Transient
light absorption changes observed within 500–600 nm reveal two processes following photodissociation:
electronic relaxation up to 400 ps after dissociation and a partial religation during 3 ns. The kinetics of oxygen geminate recombination at pH 7 and 22°C has a monoexponential decay with a lifetime of 1.5 ns ± 0.1 ns.
Effect of Formation of van der Waals Complexes on Molecular Physical Properties
Authors: Godzik K. , Hays T. R. , Henke W. E. , Selzle H. L. , Schlag E. W. , Lin S. H.
Published: March 2007

Experimental data for anthracene‐argon van der Waals complexes are presented as a function
of bound argon atoms. The results are interpreted by a new theoretical model which is based
on the Hartree‐Fock method and can explain molecular physical properties in the transition
region from isolated gaseous molecules to the condensed phase.