bluuebunny/crossref_metadata_2025 huggingface dataset:
Oscillation Control of Quay-Side Container Cranes Using Cable-Length Manipulation
Authors: Masoud Ziyad N.
Published: March 2007

Cranes play a very important role in the shipping industry. As a result there is an increasing demand on faster and safer cranes. Inertial forces on crane payloads due to crane-commanded trajectories can cause payloads to experience large sway oscillations. Consequently, sway control on quay-side container cranes is becoming a requirement rather than a luxury. Some modern quay-side container cranes use independent front and rear hoisting cables. This degree of freedom can be utilized to control payload sway oscillations. In this work, a delayed feedback algorithm is used to produce a controlled differential change in the length of the front and rear hoisting cables of a typical quay-side container crane to reduce payload sway.
Vesicle Formation at the Plasma Membrane and Trans-Golgi Network: The Same but Different
Authors: McNiven Mark A. , Thompson Heather M.
Published: March 2007

An elaborate vesicle transport system supports the active exchange of membranes and protein cargo between the plasma membrane and the trans-Golgi network. Many observations suggest that highly conserved mechanisms are used in vesicle formation and scission. Such similarity is found both at the level of the receptor-ligand sequestration process that uses clathrin and associated polymeric and monomeric adaptor proteins, and in the machinery used to deform and vesiculate lipid membranes.
High Gamma Power Is Phase-Locked to Theta Oscillations in Human Neocortex
Authors: Canolty R. T. , Edwards E. , Dalal S. S. , Soltani M. , Nagarajan S. S. , Kirsch H. E. , Berger M. S. , Barbaro N. M. , Knight R. T.
Published: March 2007

We observed robust coupling between the high- and low-frequency bands of ongoing electrical activity in the human brain. In particular, the phase of the low-frequency theta (4 to 8 hertz) rhythm modulates power in the high gamma (80 to 150 hertz) band of the electrocorticogram, with stronger modulation occurring at higher theta amplitudes. Furthermore, different behavioral tasks evoke distinct patterns of theta/high gamma coupling across the cortex. The results indicate that transient coupling between low- and high-frequency brain rhythms coordinates activity in distributed cortical areas, providing a mechanism for effective communication during cognitive processing in humans.
Evidence for a Polar Ethane Cloud on Titan
Authors: Griffith C. A. , Penteado P. , Rannou P. , Brown R. , Boudon V. , Baines K. H. , Clark R. , Drossart P. , Buratti B. , Nicholson P. , McKay C. P. , Coustenis A. , Negrao A. , Jaumann R.
Published: March 2007

Spectra from Cassini's Visual and Infrared Mapping Spectrometer reveal the presence of a vast tropospheric cloud on Titan at latitudes 51° to 68° north and all longitudes observed (10° to 190° west). The derived characteristics indicate that this cloud is composed of ethane and forms as a result of stratospheric subsidence and the particularly cool conditions near the moon's north pole. Preferential condensation of ethane, perhaps as ice, at Titan's poles during the winters may partially explain the lack of liquid ethane oceans on Titan's surface at middle and lower latitudes.
An Alternative Bactericidal Mechanism of Action for Lantibiotic Peptides That Target Lipid II
Authors: Hasper Hester E. , Kramer Naomi E. , Smith James L. , Hillman J. D. , Zachariah Cherian , Kuipers Oscar P. , de Kruijff Ben , Breukink Eefjan
Published: March 2007

Lantibiotics are polycyclic peptides containing unusual amino acids, which have binding specificity for bacterial cells, targeting the bacterial cell wall component lipid II to form pores and thereby lyse the cells. Yet several members of these lipid II–targeted lantibiotics are too short to be able to span the lipid bilayer and cannot form pores, but somehow they maintain their antibacterial efficacy. We describe an alternative mechanism by which members of the lantibiotic family kill Gram-positive bacteria by removing lipid II from the cell division site (or septum) and thus block cell wall synthesis.
Probing Nanoscale Ferroelectricity by Ultraviolet Raman Spectroscopy
Authors: Tenne D. A. , Bruchhausen A. , Lanzillotti-Kimura N. D. , Fainstein A. , Katiyar R. S. , Cantarero A. , Soukiassian A. , Vaithyanathan V. , Haeni J. H. , Tian W. , Schlom D. G. , Choi K. J. , Kim D. M. , Eom C. B. , Sun H. P. , Pan X. Q. , Li Y. L. , Chen L. Q. , Jia Q. X. , Nakhmanson S. M. , Rabe K. M. , Xi X. X.
Published: March 2007

We demonstrated that ultraviolet Raman spectroscopy is an effective technique to measure the transition temperature (
T
c
) in ferroelectric ultrathin films and superlattices. We showed that one-unit-cell-thick BaTiO
3
layers in BaTiO
3
/SrTiO
3
superlattices are not only ferroelectric (with
T
c
as high as 250 kelvin) but also polarize the quantum paraelectric SrTiO
3
layers adjacent to them.
T
c
was tuned by ∼500 kelvin by varying the thicknesses of the BaTiO
3
and SrTiO
3
layers, revealing the essential roles of electrical and mechanical boundary conditions for nanoscale ferroelectricity.
Early Reactivation of European Rivers During the Last Deglaciation
Authors: Ménot Guillemette , Bard Edouard , Rostek Frauke , Weijers Johan W. H. , Hopmans Ellen C. , Schouten Stefan , Damsté Jaap S. Sinninghe
Published: March 2007

During the Last Glacial Maximum, the sea-level lowstand combined with the large extent of the Fennoscandian and British ice sheets led to the funneling of European continental runoff, resulting in the largest river system that ever drained the European continent. Here, we show an abrupt and early reactivation of the European hydrological cycle at the onset of the last deglaciation, leading to intense discharge of the Channel River into the Bay of Biscay. This freshwater influx, probably combined with inputs from proglacial or ice-dammed lakes, dramatically affected the hydrology of the region, both on land and in the ocean.
C-Terminal Signal Sequence Promotes Virulence Factor Secretion in
Mycobacterium tuberculosis
Authors: Champion Patricia A. DiGiuseppe , Stanley Sarah A. , Champion Matthew M. , Brown Eric J. , Cox Jeffery S.
Published: March 2007

Mycobacterium tuberculosis
uses the ESX-1/Snm system [early secreted antigen 6 kilodaltons (ESAT-6) system 1/secretion in mycobacteria] to deliver virulence factors into host macrophages during infection. Despite its essential role in virulence, the mechanism of ESX-1 secretion is unclear. We found that the unstructured C terminus of the CFP-10 substrate was recognized by Rv3871, a cytosolic component of the ESX-1 system that itself interacts with the membrane protein Rv3870. Point mutations in the signal that abolished binding of CFP-10 to Rv3871 prevented secretion of the CFP-10 (culture filtrate protein, 10 kilodaltons)/ESAT-6 virulence factor complex. Attachment of the signal to yeast ubiquitin was sufficient for secretion from
M. tuberculosis
cells, demonstrating that this ESX-1 signal is portable.
Response to Comment on "Large-Scale Sequence Analysis of Avian Influenza Isolates"
Authors: Obenauer John C. , Fan Yiping , Naeve Clayton W.
Published: March 2007

We repeated the dN/dS analysis as described by Holmes
et al
. using the methods and data as described in our original report. We obtained essentially the same results and agree that it cannot be concluded from dN/dS calculations whether PB1-F2 is under positive, negative, or neutral selection.
Near-Threshold Inelastic Collisions Using Molecular Beams with a Tunable Velocity
Authors: Gilijamse Joop J. , Hoekstra Steven , van de Meerakker Sebastiaan Y. T. , Groenenboom Gerrit C. , Meijer Gerard
Published: March 2007

Molecular scattering behavior has generally proven difficult to study at low collision energies. We formed a molecular beam of OH radicals with a narrow velocity distribution and a tunable absolute velocity by passing the beam through a Stark decelerator. The transition probabilities for inelastic scattering of the OH radicals with Xe atoms were measured as a function of the collision energy in the range of 50 to 400 wavenumbers, with an overall energy resolution of about 13 wavenumbers. The behavior of the cross-sections for inelastic scattering near the energetic thresholds was accurately measured, and excellent agreement was obtained with cross-sections derived from coupled-channel calculations on ab initio computed potential energy surfaces.
Determinants of Democratization
Authors: Wacziarg Romain
Published: March 2007

Economic Origins of Dictatorship and Democracy
.
By Daron Acemoglu and James A. Robinson
. Cambridge University Press, New York, 2006. 431 pp. $35, £25. ISBN 0-521-85526-8.

The authors offer an ambitious and sweeping comparative account of the political economy of the creation and consolidation of democracy.
Maternal exposure to dexamethasone or cortisol in early pregnancy differentially alters insulin secretion and glucose homeostasis in adult male sheep offspring
Authors: De Blasio M. J. , Dodic M. , Jefferies A. J. , Moritz K. M. , Wintour E. M. , Owens J. A.
Published: March 2007

An adverse intrauterine environment increases the risk of developing various adult-onset diseases, whose nature varies with the timing of exposure. Maternal undernutrition in humans can increase adiposity, and the risk of coronary heart disease and impaired glucose tolerance in adult life, which may be partly mediated by maternal or fetal endocrine stress responses. In sheep, dexamethasone in early pregnancy impairs cardiovascular function, but not glucose homeostasis in adult female offspring. However, male offspring are often more susceptible to early life “programming”. Pregnant sheep were infused intravenously with saline (0.19 ml/h), dexamethasone (0.48 mg/h), or cortisol (5 mg/h), for 2 days from 26 to 28 days of gestation. In male offspring, size at birth and postnatal growth were measured, and glucose tolerance [intravenous glucose tolerance test (IVGTT)], insulin secretion, and insulin sensitivity of glucose, α-amino nitrogen, and free fatty acid metabolism were assessed at 4 yr of age. We show that cortisol, but not dexamethasone, treatment of mothers causes fasting hyperglycemia in adult male offspring. Maternal cortisol induced a second-phase hyperinsulinemia during IVGTT, whereas maternal dexamethasone induced a first-phase hyperinsulinemia. Dexamethasone improved glucose tolerance, while cortisol had no impact, and neither affected insulin sensitivity. This suggests that maternal glucocorticoid exposure in early pregnancy alters glucose homeostasis and induces hyperinsulinemia in adult male offspring, but in a glucocorticoid-specific manner. These consequences of glucocorticoid exposure in early pregnancy may lead to pancreatic exhaustion and diabetes longer term and are consistent with stress during early pregnancy contributing to such outcomes in humans.
NH2terminus of serum and glucocorticoid-regulated kinase 1 binds to phosphoinositides and is essential for isoform-specific physiological functions
Authors: Pao Alan C. , McCormick James A. , Li Hongyan , Siu John , Govaerts Cedric , Bhalla Vivek , Soundararajan Rama , Pearce David
Published: March 2007

Serum and glucocorticoid regulated kinase 1 (SGK1) has been identified as a key regulatory protein that controls a diverse set of cellular processes including sodium (Na+) homeostasis, osmoregulation, cell survival, and cell proliferation. Two other SGK isoforms, SGK2 and SGK3, have been identified, which differ most markedly from SGK1 in their NH2-terminal domains. We found that SGK1 and SGK3 are potent stimulators of epithelial Na+channel (ENaC)-dependent Na+transport, while SGK2, which has a short NH2terminus, is a weak stimulator of ENaC. Further characterization of the role of the SGK1 NH2terminus revealed that its deletion does not affect in vitro kinase activity but profoundly limits the ability of SGK1 either to stimulate ENaC-dependent Na+transport or inhibit Forkhead-dependent gene transcription. The NH2terminus of SGK1, which shares sequence homology with the phosphoinositide 3-phosphate [PI( 3 )P] binding domain of SGK3, binds phosphoinositides in protein lipid overlay assays, interacting specifically with PI( 3 )P, PI( 4 )P, and PI( 5 )P, but not with PI( 3 , 4 , 5 )P3. Moreover, a point mutation that reduces phosphoinositide binding to the NH2terminus also reduces SGK1 effects on Na+transport and Forkhead activity. These data suggest that the NH2terminus, although not required for PI 3-kinase-dependent modulation of SGK1 catalytic activity, is required for multiple SGK1 functions, including stimulation of ENaC and inhibition of the proapoptotic Forkhead transcription factor. Together, these observations support the idea that the NH2-terminal domain acts downstream of PI 3-kinase-dependent activation to target the kinase to specific cellular compartments and/or substrates, possibly through its interactions with a subset of phosphoinositides.
Basolateral P2X4-like receptors regulate the extracellular ATP-stimulated epithelial Na+channel activity in renal epithelia
Authors: Zhang Yanjun , Sanchez Daniel , Gorelik Julia , Klenerman David , Lab Max , Edwards Christopher , Korchev Yuri
Published: March 2007

Extracellular ATP initiates potent effects on sodium transport across renal epithelia through membrane-associated purinergic receptors. Dependent on the location of these receptors, ATP either inhibits or stimulates sodium reabsorption. Using A6 cells, transepithelial electrical resistance measurements, and scanning ion conductance microscopy, we have identified the purinergic receptors involved in the stimulatory action on the epithelial cell basolateral plasma membrane. Addition of the potent P2X4receptor agonist 2-methylthio-ATP (2MeSATP) to the basolateral side of the A6 monolayer stimulated amiloride-sensitive sodium conductance and produced similar cell morphological changes to those found with ATPγS, aldosterone, or hypotonic stress. The agonist potency order determined by sodium conductance changes of the monolayer was: 2MeSATP ≥ ATPγS > CTP, a similar agonist potency profile to that of cloned P2X4receptors but with higher sensitivity for β, γ-methylene-ATP and α,β-methylene-ATP. We further demonstrated that the ATP effect on sodium transport was potentiated by ivermectin, not blocked by suramin and PPADS, enhanced by Zn2+but not by Cu2+, and significantly reduced but not totally inhibited by brilliant blue G. These results led us to conclude that basolateral P2X4-like receptors were involved. We suggest that there is a reciprocal purinergic system acting both at a basolateral and apical location for control of Na+transport. This requires a mechanism within the cell that leads to either basolateral or apical ATP release to regulate renal tubular function.
Role of the AT1Areceptor in the CO2-induced stimulation of HCO3−reabsorption by renal proximal tubules
Authors: Zhou Yuehan , Bouyer Patrice , Boron Walter F.
Published: March 2007

The proximal tubule (PT) is major site for the reabsorption of filtered HCO3−. Previous work on the rabbit PT showed that 1) increases in basolateral (BL) CO2concentration ([CO2]BL) raise the HCO3−reabsorption rate ( JHCO3), and 2) the increase that luminal angiotensin II (ANG II) produces in JHCO3is greatest at 0% [CO2]BLand falls to nearly zero at 20%. Here, we investigate the role of angiotensin receptors in the [CO2]BLdependence of JHCO3in isolated perfused PTs. We found that, in rabbit S2 PT segments, luminal 10−8M saralasin (peptide antagonist of ANG II receptors), lowers baseline JHCO3(5% CO2) to the value normally seen at 0% in the absence of inhibitors and eliminates the JHCO3response to changes in [CO2]BL. However, basolateral 10−8M saralasin has no effect. As with saralasin, luminal 10−8M candesartan (AT1antagonist) reduces baseline JHCO3and eliminates the [CO2]BLdependence of JHCO3. Luminal 10−7M PD 123319 (AT2antagonist) has no effect. Finally, we compared PTs from wild-type and AT1A-null mice of the same genetic background. Knocking out AT1Amodestly lowers baseline JHCO3and, like luminal saralasin or candesartan in rabbits, eliminates the JHCO3response to changes in [CO2]BL. Our accumulated evidence suggests that ANG II endogenous to the PT binds to the apical AT1Areceptor and that this interaction is critical for both baseline JHCO3and its response to changes in [CO2]BL. Neither apical AT2receptors nor basolateral ANG II receptors are involved in these processes.
Development of Selectivity for Natural Sounds in the Songbird Auditory Forebrain
Authors: Amin Noopur , Doupe Allison , Theunissen Frédéric E.
Published: March 2007

In adult songbirds, auditory neurons in the primary auditory forebrain region of field L and a secondary auditory forebrain region of caudal mesopallium (CM) are highly responsive to natural sounds, such as conspecific song. Because these nuclei are involved in sensory representations of songs, we investigated how their function changes during development. We recorded neural responses to conspecific and tutor song and acoustically matched synthetic sounds in field L and lateral CM (CLM) of urethane-anesthetized juvenile male zebra finches of approximately 35 days of age. At this age, juvenile songbirds are memorizing the songs of their adult tutors but do not yet sing mature song. They are also starting to recognize songs of individual conspecifics. Compared with adult auditory forebrain neurons, juvenile neurons in field L were on average less responsive to auditory stimuli and exhibited less selectivity for natural sounds compared with the synthetic sounds. This developmental effect was more pronounced in the secondary subregions of L1 and L3 than in the primary thalamo-recipient subregion L2 of field L. CLM showed adultlike selectivity for natural sounds. Also, we did not find any evidence of memory for the tutor song in either field L or CLM. We note that the neural development of selective responses to conspecific song in the secondary subregions of field L is correlated with the emergence of individual song preference around 35 days of age. Therefore we suggest that the emergence of natural sound selectivity in field L could be important for the behavioral development of song recognition.
Role of Endogenous Release of Norepinephrine in Muscle Spasms After Chronic Spinal Cord Injury
Authors: Rank Michelle M. , Li Xiaole , Bennett David J. , Gorassini Monica A.
Published: March 2007

The recovery of persistent inward currents (PICs) and motoneuron excitability after chronic spinal cord transection is mediated, in part, by the development of supersensitivity to residual serotonin (5HT) below the lesion. The purpose of this paper is to investigate if, like 5HT, endogenous sources of norepinephrine (NE) facilitate motoneuron PICs after chronic spinal transection. Cutaneous-evoked reflex responses in tail muscles of awake chronic spinal rats were measured after increasing presynaptic release of NE by administration of amphetamine. An increase in long-lasting reflexes, known to be mediated by the calcium component of the PIC (CaPIC), was observed even at low doses (0.1–0.2 mg/kg) of amphetamine. These findings were repeated in a reduced S2 in vitro preparation, demonstrating that the increased long-lasting reflexes by amphetamine were neural. Under intracellular voltage clamp, amphetamine application led to a large facilitation of the motoneuron CaPIC. This indicates that the increases in long-lasting reflexes induced by amphetamine in the awake animal were, in part, due to actions directly on the motoneuron. Reflex responses in acutely spinal animals were facilitated by amphetamine similar to chronic animals but only at doses that were ten times greater than that required in chronic animals (0.2 mg/kg chronic vs. 2.0 mg/kg acute), pointing to a development of supersensitivity to endogenous NE in chronic animals. In summary, the increases in long-lasting reflexes and associated motoneuron CaPICs by amphetamine are likely due to an increased release of endogenous NE, which motoneurons become supersensitive to in the chronic stages of spinal cord injury.
Varnish Ablation Control by Optical Coherence Tomography
Authors: Góra Michalina , Targowski Piotr , Rycyk Antoni , Marczak Jan
Published: March 2007

Preliminary results of the application of optical coherence tomography (OCT), in particular in its spectral mode (SOCT) to the control of a varnish ablation process, are presented. Examination of the ablation craters made with an Er:YAG laser allows optimization of the laser emission parameters controlling fluence with respect to efficiency and safety of the ablation process. Results of measurements of ablation crater depth as a function of the number of pulses for a given fluence are presented for selected resins. This validates the applicability of SOCT to calibration of ablation conditions for the particular laser-varnish-paint layer combinations, and of its usage in planning the varnish ablation procedure. These results also imply that a review of conventional ablation thresholds is called for. Applicability of the SOCT technique to contemporaneous in situ monitoring of the range of varnish ablation is discussed.
Automatic Identification of Artistic Pigments by Raman Spectroscopy Using Fuzzy Logic and Principal Component Analysis
Authors: Castanys M. , Soneira M. J. , Perez-Pueyo R.
Published: March 2007

This work offers an automatic identification system of Raman spectra of artistic pigments. The proposed methodology is based on a fuzzy logic system, and uses principal component analysis to reduce redundancies in data and the correlation operator as an index of similarity between two Raman spectra. Moreover, as sometimes pigments are used in mixtures by artist, the designed system is able to recognize binary mixtures of pigments on the basis of their Raman fingerprints.
Characterization of Laser-Generated Microparticles by Means of a Dust Monitor and SEM Imaging
Authors: Wurster Roland , Pentzien Simone , Conradi Andrea , Krüger Jörg
Published: March 2007

Nanosecond laser (1064 nm wavelength) cleaning of artificially soiled paper as a model sample simulating a real-world artwork was performed. During the cleaning process, the ejection of particles was monitored in situ by means of a dust monitor (8 size classes, ranging from 0.3μm to>2 μm) and ex situ using a mini-cascade impactor (MKI, 5 stages). The cleaning result was analyzed by scanning electron microscopy (SEM) considering possible laser-induced damages to the substrate. Size distributions of emitted particles were measured depending on the processing parameters: laser fluence,F, and pulse number per spot,N. High numbers of large (>2 μm) particles were collected by the mini-cascade impactor indicating a gas dynamical liftoff process. Obviously, these particles were not affected by the laser-matter interaction. The different methods (SEM, MKI, and dust monitor) are compared with respect to their usefulness for a proper interpretation of the cleaning results.
Multianalytical Study of Laser Pulse Duration Effects in the IR Laser Cleaning of Wall Paintings from the Monumental Cemetery of Pisa
Authors: Andreotti A. , Colombini M. P. , Nevin A. , Melessanaki K. , Pouli P. , Fotakis C.
Published: March 2007

The feasibility of laser cleaning for the removal of a variety of surface deposits from fragments of real wall paintings from the monumental cemetery of Pisa using Nd:YAG at 1064 nm at (μs), (ns), and (ps) regimes is presented. Multianalytical investigations of the samples from irradiated surfaces of fragments were carried out in order to characterize the original and added materials and to detect any laser-induced alterations; analysis included scanning electron microscopy (SEM), Fourier
transform infrared spectroscopy (FTIR), laser-induced breakdown spectroscopy (LIBS),
pyrolysis-gas chromatography-mass spectrometry (PY-GC-MS), and gas chromatography-mass spectrometry (GC-MS). The presence of nitrocellulose and pure lead contaminations on the surface of the samples has been identified. Assessment of the laser cleaning has highlighted the importance of the optimization of laser parameters, specifically pulse duration and fluence at the specified wavelength.
Remote Multicolor Excitation Laser-Induced Fluorescence Imaging
Authors: Grönlund Rasmus , Hällström Jenny , Johansson Ann , Barup Kerstin , Svanberg Sune
Published: March 2007

Remote laser-induced fluorescence of stone materials was performed with application towards cultural heritage. Fluorescence was induced in targets ∼60 m from a mobile lidar laboratory by ultraviolet laser light, either from a frequency-tripled Nd:YAG laser or from an optical parametric oscillator system. Analysis was performed on combined spectra from the different excitation wavelengths and it was noted that important additional information can be gained when using several excitation wavelengths.
Spectroscopic Techniques Applied to the Study of Italian Painted Neolithic Potteries
Authors: Angeli Lucia , Arias Claudio , Cristoforetti Gabriele , Fabbri Cristina , Legnaioli Stefano , Palleschi Vincenzo , Radi Giovanna , Salvetti Azenio , Tognoni Elisabetta
Published: March 2007

In the field of cultural heritage, the study of the materials used by the artist is useful both for the knowledge of the artwork and for conservation and restoring interventions. In this communication, we present results of some decorations analysis obtained by the use of two complementary laser techniques: micro-LIBS and micro-Raman spectroscopy. With both techniques it is possible to operate in a practically nondestructive way on the artwork itself, without sampling or pretreatment. Micro-Raman spectroscopy gives information on the molecular structure of the pigments used, while micro-LIBS can give quantitative information about the elemental composition of the same materials. In this paper, qualitative results are reported obtained on the study of some Neolithic potteries coming from the archaeological site of Trasano (Matera); the fragments show decorations in different colors, red, black, and white. The aim of the study was detecting whether the colored decorations were made by using added pigments or came from the manufacturing process.
Observation of the Laser Cleaning Effect on the Gotland Sandstone Elemental Composition
Authors: Jasińska Marta , Bredal-Jørgensen Jørn , Śliwiński Gerard
Published: March 2007

Changes of the elemental composition due to laser surface cleaning of a naturally crusted historical sandstone were investigated by means of the SEM/EDX technique. Data obtained for stone samples prior to and after laser irradiation were compared with those for noncrusted, reference ones. It has been observed that the crust removal resulting from ablative cleaning was accompanied by a decrease of the partial content of elements Al, S, K, Ca, and Mg in the range of 60–80% of their initial value recorded for the noncleaned, crust-covered stone surface. In the stone layer just under the crust coverage, a structure characterized by intergranular spaces between the SiO2 grains being the main sandstone component filled with degraded binder was observed. From the coincidence of the binder destruction and chemical composition of the crust, the stone surface destruction due to the long-term interaction of environmental pollution was deduced. The spatial distributions of individual elements
obtained by mapping after laser irradiation indicated that besides SiO2 the content of elemental components in the sandstone surface layer decreased by 50%, whereas for Fe with the initial content of 4% and other surface remnants: P, Ti, Zn, and Cl—all below 1%, insignificant changes were only revealed. It was concluded in agreement with the literature that surface cleaning by means of the 1064 nm laser does not cause removal of iron from the sandstone surface.
A Comprehensive Study for the Laser Cleaning of Corrosion Layers due to Environmental Pollution for Metal Objects of Cultural Value: Preliminary Studies
on Artificially Corroded Coupons
Authors: Siatou A. , Charalambous D. , Argyropoulos V. , Pouli P.
Published: March 2007

This paper is focused on the systematic investigation of the layer-by-layer removal of corrosion products on artificially corroded metal coupons aiming to introduce a
methodology for the optimum laser cleaning approach of historical metal objects. Thus, it is very important to determine the chemical composition of the studied surfaces before and after irradiation. A series of laser cleaning studies has been performed on test coupons (reference and artificially corroded). Wavelength and pulse duration effects are investigated. Initial studies were focused on the use of infrared (1064 nm) and
ultraviolet (355 nm and 248 nm) radiations of nanosecond (ns) pulse duration. Damage and removal threshold values were determined for the substrates and the corrosion layers, respectively. The irradiated surfaces are evaluated microscopically under the optical and the scanning electron microscope, while the mineralogical and chemical composition of the various layers is determined with X-ray diffraction and SEM-EDAX analyses, respectively. The results obtained are providing a comprehensive approach for understanding the main mechanisms that are significant in the different laser
cleaning regimes, while the optimum cleaning methodologies for the
studied materials are being established.
New Samarium(III), Gadolinium(III), and Dysprosium(III) Complexes of Coumarin‐3‐Carboxylic Acid as Antiproliferative Agents
Authors: Kostova Irena , Momekov Georgi , Stancheva Peya
Published: March 2007

New complexes of samarium(III), gadolinium(III), and dysprosium(III) with coumarin‐3‐carboxylic acid (HCCA) were prepared by the reaction of the ligand with respective metal nitrates in ethanol. The structures of the final complexes were determined by means of physicochemical data, elemental analysis, IR and Raman spectra. The metal‐ligand binding mode in the new Ln(III) complexes of coumarin‐3‐carboxylic acid was elucidated. The vibrational study gave evidence for bidentate coordination of CCA− to Ln(III) ions through the carbonylic oxygen and the carboxylic oxygen atoms. The complexes were tested for antiproliferative activitiy on the chronic myeloid leukemia‐derived K‐562, overexpressing the BCR‐ABL fusion protein. Cytotoxicity towards tumor cells was determined for a broad concentration range. The samarium salt exerted a very weak antiproliferative effect on these cells. This is in contrast to the lanthanide complexes, especially samarium complex, which exhibited potent antiproliferative activity. The present study confirms our previous observations that the lanthanide complexes of coumarins exhibit antiproliferative activity towards K‐562 cell line.
Multiple Photon IR Dissociation of (CF3)3CBr and Synthesis of(CF3)3CI in Laser‐Radical Chemical Reactions
Authors: Bagratashvili V. N. , Burimov V. N. , Kuzmin M. V. , Letokhov V. S. , Sviridov A. P.
Published: March 2007

CO2‐laser induced multiple photon excitation and dissociation of the molecule (CF3)3CBr in the environment of I2 has been studied experimentally and theoretically. The synthesis of the (CF3)3CI molecule in laser‐radical chemical reactions with high yield has been demonstrated.
Application of IR Laser Optoacoustic Spectroscopy in Gas Chromatography
Authors: Zharov V. P. , Montanari S. G. , Letokhov V. S.
Published: March 2007

A combined GC–LOAS system (a gas chromatograph and a laser optoacoustic spectrometer)
has been devised and comprehensively studied, and a number of typical chromatographic tasks solved with this system is given. The sensitivity of the OA detector used in the system with respect to the detectable absorption factor is 2 · 10−7 cm−1 which corresponds to a concentration sensitivity for methanol (λ = 9.695 μm) of about 10−10 g/cm3. It is shown that the chromatographic resolution almost does not become worse if the OA detector with a 2.7 cm3 chamber volume is used with a packed column. The experimental results are presented which show the identifying potentialities of the laser OA method in chromatographic analysis of a mixture of butanol isomers and the increased resolution of a chromatographic analysis of isopropyl alcohol admixture in ethyl alcohol. Also, it is shown how to solve the task of analyzing the xylene isomers which cannot be separated in the column. The laser OA
method has been qualitatively compared with other selective methods in gas chromatography.
Recommendations have been proposed for improving the characteristics of the combined
GC–LOAS system.
Time‐Resolved Spectroscopy of Polymethine J‐Aggregates
Authors: Feller K.-H. , Gadonas R. , Krasauskas V. , Fidler V. , Vajda S.
Published: March 2007

The deactivation process of J‐aggregates of DDEOCI (3,3′‐diethyl‐5,5′‐diphenyl‐9‐ethyl‐oxacarbocyanine
iodide) was investigated by means of steady‐state and time‐resolved absorption and fluorescence
spectroscopy. The decay kinetics as well as the transient absorption spectra have been analyzed including
different aggregate structures and exciton‐exciton annihilation.
Picosecond Time Resolved Absorption Experiments of Iodine in Complexing Solvents
Authors: Besnard Marcel , Del Campo Nathalie , De Violet Philippe Fornier , Rulliere Claude
Published: March 2007

Transient absorption spectra of I2 diluted in “inert” (CCl4, n‐heptane) solvents and electron donor
solvents of increasing complexing strength (CS2, benzene, dioxane, pyridine) have been measured (in the
spectral range 400–800 nm) at different times (from 20 ps to 1 ns) after excitation using 25 ps pulses at λ = 532 nm. In inert solvents, the time evolution of the transient spectra are consistent with the model
recently proposed by Harris et al.1

Such a behaviour is in marked contrast with the experimental observation in strongly complexing
solvents (pyridine). This is interpreted as resulting from a competition between geminate recombination
and formation of a complex between the solvent and atomic iodine (I•) formed by the photodissociation
process. In intermediate complexing solvents these two processes seem to coexist.
Laser Excitation Spectra and Lifetime Measurements of the CO d(3Δi)State
Authors: Miller Bradley E. , Schulz Peter A.
Published: March 2007

CO in a supersonic pulsed beam is excited to the d3Δi state by VUV photons generated in a nonlinear
four‐wave mixing scheme. An excitation spectrum of the CO d3Δi (ν′ = 20, J′ = 1–3) is obtained at a
resolution of 0.8 cm−1 for the first time. The radiative lifetimes of the rotational states are measured as
1.70 ± 0.08 μs, which are similar to but shorter than the lifetimes associated with lower vibrational levels.
Cars Diagnostic on a PhotochemicalReactor for IR Laser Induced Production of Si and Si3N4 Powders
Authors: Fantoni R. , Bijnen F. , Djurić N. , Piccirillo S.
Published: March 2007

In a flow reactor a low power (up to 50 W) CW CO2 laser tuned at 944,19 cm−1 has been focussed in order
to produce Si and Si3N4 ultrafine powders from SiH4 and SiH4/NH3 mixtures.

Among possible on‐line optical diagnostics, two different CARS techniques have been used to monitor
the excitation process and to measure average reaction temperatures in collinear geometry. In broad‐band
CARS at low resolution (≈6.0 cm−1) the reactant temperature is measured from the attenuation of the
corresponding integrated peak intensity below and at the dissociation threshold. In narrow‐band
experiments the temperature reached by the dissociating reactants below and above the threshold is
inferred from the spectral shape (measured with 0.2 cm−1 resolution) of the envelope of rovibrational
CARS transitions involved.

Results obtained at the threshold for SiH4 dissociation are in agreement with previous data on gas‐phase
pyrolysis in a thermal process. For the SiH4/NH3 reaction the difficulty in obtaining stoichiometric Si3N4
has been related to the cooling effect of large NH3 addition to the SiH4 warmed up in the laser absorption.
Vector Correlations in Molecular Photofragmentations
Authors: Comes F. J.
Published: March 2007

Photofragmentation spectroscopy—the study of “half collisions” with polarized light of subdoppler line
width—opens a window to look into the structure of molecules. The energy partitioning among the
particular degrees of freedom of the products of the fragmentation reaction is described by the scalar
properties, the direction and magnitude of a particular type of motion is described by the vector
properties. The measurement of the scalar and vector properties allows a pictorial view of the intermediate
state. The forces which make the fragments fly apart or rotate and vibrate can be “seen” from the line
shapes. Information on the unstable intermediate state is gained from the stable fragments long after the
dissociation of the parent molecule. In particular, information on the “lifetime” of the intermediate on a
femtosecond time scale can be obtained.

A number of molecules, mainly three and four atomic, have been studied by this technique. Hydrogen
peroxide has shown up as a textbook example. A complete analysis was possible including not only
correlation of different types of fragment motion but also a correlation of the two coincident particles
formed from the same parent molecule. The experimental results are in full agreement with recent
calculations of the dynamics of the fragmentation on newly obtained potential energy surfaces. Hydrogen
peroxide shows a strong dependence of its potential energy on the dihedral angle in the two electronic
states amenable to laser excitation. This experiment further demonstrates that an analysis is also possible
if two states are excited simultaneously.

Another good example is the fragmentation of hydrazoic acid for which also coincident pair correlation
has been treated. Here again the results agree excellently with a qualitative picture which can be drawn
from recently calculated ab initio potential energy surfaces. The HN3 example is much more complicated
than the former one due to its higher structured upper potential energy surface. Strong rotational
excitation is observed in the N2 fragment leaving the NH fragment rotationally cold.

The treatment of vector correlations in molecular photofragmentation is a powerful tool for the study of
the dynamics of molecular dissociation reactions.
Kinetic and Spectroscopic Studies of Transient Species Prepared byIrmpd
Authors: Castaño F. , De Zárate A. Ortiz , Fernández J. A. , Sánchez Rayo M. N.
Published: March 2007

Infrared multiple photon absorption is known to be observed in some triatomic and most polyatomic
molecules. When the number of absorbed photons is high enough the process leads to photodissociation
and excess energy is released as vibrational, rotational and translational energy in the electronic ground
state of the fragments. The contribution of these energies is determined by standard methods, that include
laser induced fluorescence, LIF, and time‐resolved Fourier transform spectroscopy, TR‐FTS. Examples
of selected determinations are shown.

Once produced, identified and characterized, the kinetic behaviour of the transients with selected
reactants can be studied. In particular, removal rate constants of substituted carbenes, in specific
vibrational and electronic states, by atoms, olefins and simple molecules are mentioned.
Theoretical Description of The He(23S)–H2 Autoionising CollisionSystem
Authors: Vojtík J.
Published: March 2007

The ionization event in the He(23S)–H2 collision system at the collision energy of 80 me V is described by a
modified version of the trajectory surface leaking method. The approach is found to yield an improved
picture of the event which is consistent with Penning electron spectra measurements.
High Resolution Laser Spectroscopy of Small Molecules and Clusters
Authors: Beutel V. , Böhm H.-J. , Demtröder W. , Eckel H.-A. , Gress J. , Kuhn M. , Sasso A.
Published: March 2007

The combination of high resolution laser spectroscopy in collimated cold molecular beams with mass
selective detection allows investigations of rotationally resolved molecular spectra of selected molecular
species in the presence of molecules with overlapping absorption spectra. This is illustrated by some
examples, such as the isotope selective spectroscopy of Ag2–dimers or the sub‐Doppler spectroscopy of
Na3 in supersonic beam with a broad mass distribution of different clusters. Time resolved laser
spectroscopy of excited states of alkali molecules, perturbed by bound dark states or by repulsive states,
yields information about singlet–triplet mixing and predissociation rates.
Preparation and Study of Single Sized Cluster Ions in a SupersonicJet
Authors: Schlag E. W. , Selzle H. L.
Published: March 2007

Experiments with supersonic jet expansion have been performed to prepare clusters of benzene
molecules. The clusters produced in the jet are ionized by two‐photon ionization and mass analysis is
achieved in a reflectron time of flight mass spectrometer. Due to an excess energy up to several hundred
me V unimolecular decay occurs on a time‐scale from nanoseconds up to microseconds and even longer.
To discriminate against interferences from fragmentation of higher mass clusters in the observed spectra
different experiments have been performed which include a new method by which single size cluster ions
are stopped in the supersonic jet. These ions then stay isolated in space and the metastable decay of these
complexes can be analyzed without further perturbation from fragmentation of higher clusters.
On the Measurement of the Rate of Intramolecular Vibrational EnergyRedistribution via High Resolution Molecular Beam OptothermalSpectroscopy
Authors: Lehmann Kevin K. , Pate Brooks H. , Scoles G.
Published: March 2007

Using frequency resolved techniques we have been able to measure the rate of intramolecular vibrational
energy redistribution in a number of substituted acetylenes. The method of IVR rate determination is
discussed with respect to time domain measurements. The lifetimes we have determined have been quite
long, ranging from a few hundred ps to a few ns. Interesting behavior of the rate as a function of the
structure of the molecule has been observed. Results show sensitivity of the IVR rate to heavy mass
substitution and the possibility of chromophore determined lifetimes.
High Resolution Proton Energy Loss Spectroscopy of High OvertoneLevels of Polyatomic Molecules
Authors: Maring W. , Toennies J. P.
Published: March 2007

In the inelastic scattering of nearly monoenergetic proton beams (≅ 20 e V) from polyatomic molecules
such as CF4 sharp peaks are observed corresponding to the excitation of very high overtone levels
(n ≤ 14) of the infrared active modes. The collision mechanism leading to the high degree of excitation is
described and an example from recent experiments is presented. A fit of the CF4 spectra provides new
anharmonicity constants for the ν3‐mode.
Laser‐Assisted Electron‐Atom Collisions
Authors: Joachain C. J.
Published: March 2007

The theoretical methods which have been developed to analyze laser‐assisted electron‐atom collisions are
reviewed. Firstly, the scattering of an electron by a potential in the presence of a laser field is considered.
The analysis is then generalized to laser‐assisted collisions of electrons with “real” atoms having an
internal structure. Two methods are discussed: a semi‐perturbative approach suitable for fast incident
electrons and a fully non‐perturbative theory—the R‐matrix‐Floquet method—which is applicable to the
case of slow incident electrons. In particular it is shown how the dressing of the atomic states by the laser
field can affect the collision cross sections.
Laser Assisted Charge Exchange in Atomic Collisions
Authors: Castillo J. F. , Errea L. F. , Méndez L , Riera A.
Published: March 2007

We present total charge exchange cross sections for collisions of Li(1s22s2S) with H(1s) in presence of a
linear polarized laser field of intensity 0.05 ≤ I ≤ 1 TW/cm2 and wavelength 5 103 ≤ λ ≤ 14 103 Å. Our
calculation shows that the laser field can increase the cross section of this reaction by a factor of ten at
impact energies E < 0.1 ke V/a.m.u. The mechanism of this process is discussed and it is shown that both
atomic and molecular radiative transitions can take place depending on the laser wavelength employed.
Temperature Effects in Rhodamine B Dyes and Improvement in CW DyeLaser Performance
Authors: Ali M. A. , Moghaddasi J. , Ahmed S. A.
Published: March 2007

The effect of cooling the laser medium on the lasing characteristics of an organic cw dye laser, Rhodamine
B in ethylene glycol, pumped by an Argon laser was examined. Significant improvements in the
performance of this dye laser were achieved as the solvent temperature was reduced below room
temperature, namely: a significant reduction in the threshold power requirements and a considerable
increase in the attainable output power. The results obtained may be understood in terms of increased
quantum yield of the RhB dye as the temperature is reduced. This effect overrides possible negative
effects that are normally expected due to intermolecular relaxation processes and which are normally
observed for other dye lasers which already have high quantum yields at room temperature.
The Pulsed Homogeneous Laser Pyrolysis: Determination of ArrheniusParameters of CHClF2 Destruction Basing on the Model of Physical andChemical Processes
Authors: Zhitnev Yu. N. , Zakharchenko A. V. , Mordkovich N. Yu. , Nugaev T.-B. H. , Tveritinova E. A. , Timofeev V. V.
Published: March 2007

The Pulsed Homogeneous Laser Pyrolysis (PHLP) of CHClF2 initiated by IOP(20) radiation of TEA‐CO2
laser was carried out in the presence of SF6 sensitizer with the mixture components ratio 1:1 under partial
pressure of the reactant equal to 1 Torr and 2 Torr.

To describe PHLP process in the afterpulse period we suggested a kinetic model of CHClF2 thermal
destruction accounting for the inhomogeneity of laser heating of the reaction mixture and its further
cooling by the heat conduction mechanism. Applying the standard mathematical procedure for matching
the experimental results of the degree of reactant destruction, and the numeric computations of this value
made according to the suggested model, the Arrhenius parameters of the reaction of CHClF2 monomolecular
conversion in the temperature range of 1000–1200 K were unambiguously determined.
The values were obtained for the activation energy Eα = 52.8 ± 0.3 kcal/mol, and the pre‐exponential
factor A = (2.5 ± 1) · 1012 s−1.
Multiphoton Ionization of Nitrobenzene in Non‐Aqueous Solutions: Characterization of the Cation and Ion‐Molecule Chemistry
Authors: Siuzdak G. , Belbruno J. J.
Published: March 2007

The phenoxy cation has been generated in polar and nonpolar solutions by multiphoton ionization of
nitrobenzene using nanosecond pulses of 266 nm and 355 nm light. The ions have been characterized by
pulsed conductivity (ion mobility) measurements and transient absorption spectroscopy. The involvement
of the phenoxy ion in ion‐molecule chemistry with either neutral solute or solvent molecules has also
been observed and the photochemical products and quantum yields of the ion‐molecule products are
presented and compared with the neutral photochemistry results.
Theoretical Approaches to Study the Vibrational Predissociation of Van Der Waals Molecules
Authors: Delgado-Barrio G. , Serna S. , Miret-Artés S. , Roncero O. , Campos-Martínez J. , Villarreal P.
Published: March 2007

Different approaches are presented for the study of vibrational predissociation of triatomic van der Waals molecules. These methods are applied to the study of the He-I2 when I2 is excited to the B electronic state.

The applicability of these methods is discussed in detail by comparing with “exact” quantum results.