Spectrum analysis

The simple route of synthesizing gold nanoparticles via chemical reduction technique was implemented. The main focus of this study is to achieve enhanced properties of gold nanoparticles by regulating the process parameters of the synthesis. The correlation of the process parameters and resultant size of gold nanoparticles has been deliberated. The gold nanoparticles were reduced with monosodium glutamate (MSG) and further capped with chitosan to prevent agglomeration between particles. The samples were characterized with several characterization techniques. The TEM micrograph showed dispersed particles with narrow size distribution of capped gold nanoparticles with the most probable particles size distributed in the range of 16 to 18 nm. The most stable gold nanoparticles occurred after reduced with 100 mM of MSG and capped with 1g of chitosan where the SPR peaks were blue shifted as the concentration of reducing agent increases and decreasing pattern of FWHM was recorded. Gold nan...

Sugars are small carbohydrates which play numerous roles in living organisms such as storage of energy or as structural components. Modifications of specific sites within the glycan chain can modulate a carbohydrate's overall biological function as it happens with nucleic acids and proteins. Hence, identifying discrete carbohydrate modifications and understanding their biological effects is essential. A study of such processes requires of a deep knowledge of the interaction mechanism at the molecular level. Here, we use a combination of laser spectroscopy in jets and quantum mechanical calculations to characterize the interaction between phenyl-β-d-glucopyranoside and N-methylacetamide as a model to understand the interaction between a sugar and a peptide bond. The most stable structure of the molecular aggregate shows that the main interaction between the peptide fragment and the sugar proceeds via a C[double bond, length as m-dash]OH-O2 hydrogen bond. A second conformer was al...

A flavohaemoprotein (FHP) from Ralstonia eutropha, obtained in a pure and active form, has been entrapped in a film of methyl cellulose on the electrode surface and gives a stable and reproducible electrochemical response at pH 7.00 when subject to cyclic voltammetry using a glassy carbon electrode. To our knowledge, no previous direct electrochemistry had been achieved with a bacterial flavohaemoglobin, which possess both a FAD and a haem. A single couple is observed which is assigned to the haem moiety of the protein, since the same result is obtained with a semi-apo form of the protein deprived of FAD (semi-apo FHP). The data collected were further confirmed by potentiometry with a platinum electrode, and the homogeneous electron transfer rate estimated by double potential step chronocoulometry at a bare glassy carbon electrode in the presence of methyl viologen (MV). The presence of FAD in the holoprotein is easily confirmed by UV-Vis spectrophotometry, but its expected electron relay role remains elusive. The protein activates the reduction of dioxygen by about 400 mV, the reduction current being proportional to the concentration of dioxygen up to 10% in volume in the gas mixture.

Introduction . Ozone and water are key species for understanding the stability and evolution of Mars’ atmosphere; they are closely linked (along with CO, H, OH, and O) through photochemistry [1-6]. Measurements of ozone on Mars have been made by both ground based telescopes [7-13] and spacecraft [14-17]. Some of these measured the total column density of ozone [8, 11, 14] while others measured ozone above 20 km [9,10, 13]. These latter measurements are performed by measuring the O2(Δ) emission rates. Together, these results give insights into the vertical column profile of ozone on Mars. Photolysis of ozone by UV light from the sun produces O(P) and O2(Δ) with 90% efficiency [18]. The O2(Δ) state has a relatively long radiative lifetime (~ 1 hour) [19]. The O2(Δ) state can also be quenched by collisions with CO2. At altitudes less than 20 km, quenching dominates so the O2(Δ) emission near 1.27 μm traces the presence of ozone in the middle atmosphere of Mars. Since 1997, we have been...

We report investigations of HDO and H 2 O on Mars using CSHELL at the NASA IRTF for seasonal dates that span the entire Mars year. Our objective is to obtain measurements of the seasonal and latitudinal variation of the [HDO]/[H 2 O] ratio and thereby obtain better insights into the dynamics of Mars' atmosphere. The instrument slit is typically positioned N-S along the central meridian resulting in a one-dimensional map of HDO (1997HDO ( -2006) ) and/or H 2 O (2001-2006) [1]. Column densities are extracted at intervals between 0.6 and 1.0 arc-second; [HDO]/[H 2 O] ratios are calculated for various latitudes and seasons.

Introduction: Ozone and water are key species for understanding the stability and evolution of Mars' atmosphere; they are closely linked (along with CO, H, OH, and O) through photochemistry [1-4]. Photolysis of water produces the OH radical (thought to catalyze reformation of CO 2 from CO and O 2 ) and atomic hydrogen (which reacts with O 3 forming OH and O 2 ). Atomic hydrogen also reacts with O 2 (forming HO 2 ), thereby reducing the amount of O 2 available to reform O 3 from collisions between O and O 2 . Hence ozone and water should be anti-correlated on Mars. Photolysis of O 3 produces O 2 (a 1 ∆ g ) with 90% efficiency [5], and the resulting emission band system near 1.27 µm traces the presence and abundance of ozone. This approach was initially used to study ozone on Earth [6] and then applied to Mars [7]. In 1997, we measured several lines of the O 2 (a 1 ∆ g ) emission (Fig. .) using CSHELL [8] at the NASA IRTF; the O 2 (a 1 ∆ g ) state is also quenched by collisions with CO 2 . This quenching dominates at lower altitudes so that the detected emissions are used to detect ozone column densities above ~20 km. The slit was positioned N-S along Mars' central meridian resulting in a onedimensional map of ozone [9].

Living systems produce more than 90% of Earth's atmospheric methane; the balance is of geochemical origin. On Mars, methane could be a signature of either origin. Using high-dispersion infrared spectrometers at three ground-based telescopes, we measured methane and water vapor simultaneously on Mars over several longitude intervals in northern early and late summer in 2003 and near the vernal equinox in 2006. When present, methane occurred in extended plumes, and the maxima of latitudinal profiles imply that the methane was released from discrete regions. In northern midsummer, the principal plume contained ∼19,000 metric tons of methane, and the estimated source strength (≥0.6 kilogram per second) was comparable to that of the massive hydrocarbon seep at Coal Oil Point in Santa Barbara, California.

This work presents the development and validation of the K0-WEB software, dedicated to the determination of elemental concentrations based on the k₀-standardization method of Neutron Activation Analysis (NAA). This method, recognized for its high accuracy, enables multielement analyses of samples without the need for standards, relying on the precise characterization of facilities and the use of nuclear parameters such as k0factors, Q₀, and decay constants. The system stands out for its innovative web-based architecture and the automation of nuclear data import, providing originality and operational autonomy. The software integrates essential corrections-such as cascade summing, geometry factor, and allows step-by-step monitoring of calculations, interactive visualization, and report generation. The validation of K0-WEB was carried out by comparing its results with those of the K0-IPEN program, previously submitted to an international intercomparison exercise of the International Atomic Energy Agency (IAEA), ensuring the reliability of the new system. The experimental part employed standardized data from IAEA-TECDOC-2026. Concentration, efficiency, and thermal and epithermal flux parameter calculations were performed according to methodologies established in the literature, with emphasis on the bare triple monitor method and the cadmium ratio method. Additionally, an uncertainty analysis based on error propagation and covariance matrix was applied. The results demonstrated the validation of K0-WEB, and it can be concluded that K0-WEB represents an innovative, accurate, and efficient solution for application in NAA laboratories.

This study tested the following hypotheses: (1) acid-cleaned and passivated unalloyed titanium implants have higher surface energies (which are considered desirable for bone implants) than ethanol-cleaned titanium; (2) higher temperatures of heat treatment of unalloyed titanium result in higher surface energies; and (3) these changes can be related to changes in surface composition and roughness. Thus, unalloyed titanium specimens were either acid-cleaned and passivated (CP) or ethanol-cleaned (Et). Each set was then divided into 3 groups and heat-treated for 1 hour at 316 degrees C (600 degrees F), 427 degrees C (800 degrees F), and 538 degrees C (1,000 degrees F), respectively. Surface roughness values for each of these groups were determined using atomic force microscopy, while surface compositions were determined using Auger electron, x-ray photoelectron, and Raman spectroscopic techniques. Surface energies were estimated using a 2-liquid geometric mean technique and correlated with surface roughness, elemental composition, and elemental thickness. The CP surfaces were slightly rougher than the Et specimens, which had greater oxide thickness and hydrocarbon presence. The surface oxides were composed of TiO2, Ti2O3, and possibly titanium peroxide; those heat-treated at 427 degrees C or above were crystalline. The CP specimens had carbonaceous coverage that was of a different composition from that on Et specimens. The CP specimens had significantly higher surface energies, which showed statistically significant correlations with oxide thickness and carbonaceous presence. In conclusion, ethanol cleaning of unalloyed titanium dental implants may not provide optimal surface properties when compared to cleaning with phosphoric acid followed by nitric acid passivation.

In this work, we adopt a quantum mechanical approach based on time-dependent density functional theory (TDDFT) to study the optical and electronic properties of alizarin supported on TiO 2 nano-crystallites, as a prototypical dye-sensitized solar cell. To ensure proper alignment of the donor (alizarin) and acceptor (TiO 2 nano-crystallite) levels, static optical excitation spectra are simulated using time-dependent density functional theory in response. The ultrafast photoelectron transfer from the dye to the cluster is simulated using an explicitly time-dependent, one-electron TDDFT ansatz. The model considers the δ-pulse excitation of a single active electron localized in the dye to the complete set of energetically accessible, delocalized molecular orbitals of the dye/nano-crystallite complex. A set of quantum mechanical tools derived from the transition electronic flux density is introduced to visualize and analyze the process in real time. The evolution of the created wave packet subject to absorbing boundary conditions at the borders of the cluster reveal that, while the electrons of the aromatic rings of alizarin are heavily involved in an ultrafast charge redistribution between the carbonyl groups of the dye molecule, they do not contribute positively to the electron injection and, overall, they delay the process.

Theta (6–12 Hz) field potentials and the synchronization (coherence) of these potentials present neural network indices of hippocampal physiology. Theta signals within the hippocampal formation may reflect alterations in sensorimotor integration, the flow of sensory input, and/or distinct cognitive operations. While the power and coherence of theta signals vary across lamina within the septal hippocampus, limited information is available about variation in these indices across the septotemporal (long) or areal axis. The present study examined the relationship of locomotor speed to theta indices at CA1 and dentate gyrus (DG) sites across the septotemporal axis as well as in the entorhinal cortex. Our findings demonstrate the dominant relationship of speed to theta indices at septal sites. This relationship diminished systematically with distance from the septal pole of the hippocampus at both CA1 and DG sites. While theta power at entorhinal sites varied in relation to speed, there w...

In our previous papers of the chemical constituents of Upuna borneensis (Dipterocarpaceae), the structure of new resveratrol derivatives (upunaphenols A-K, [1] upunosides A-D 5) ) were described. Further search for components with biological activities in the stem of U. borneensis resulted in the isolation of three new resveratrol derivatives. In the present paper, the isolation and characterization of three new compounds, upunaphenols L (1)-N (3), is described. Upunaphenols L (1) ([a] D 25 Ϫ13°), M (2) ([a] D 25 ϩ8°), and N (3) ([a] D 25 Ϫ31°) were purified from an acetone-soluble part of stem of U. borneensis by column chromatography over silica gel, Sephadex LH-20, ODS, and PTLC (preparative TLC). All compounds showed positive reactions to the Gibbs reagent. Upunaphenol L (1) was obtained as a yellow solid. In the high resolution (HR)-FAB-MS, an [MϪH] Ϫ ion peak was observed at m/z 1051.2979 suggesting the molecular formula of C 65 H 48 O 14 . An absorption band (1744 cm Ϫ1 ) in the IR spectrum and a signal (d C 167.7) in the 13 C-NMR spectrum showed the presence of an ester carbonyl group (C-9e) in the molecule. The 1 H-and 13 C-NMR spectral data together with 1 H-1 H shift correlation spectroscopy (COSY), 13 C-1 H COSY and 1 H detected heteronuclear multiple bond connectivity (HMBC) spectra (Table ) showed the presence of ortho-coupled aromatic protons assignable to five 4-hydroxylphenyl groups (rings A 1 -E 1 ), two sets of meta-coupled aromatic protons on a 1,2,3,5-tetrasubstituted benzene ring (rings A 2 and C 2 ) and a 3,5-dihydroxyphenyl group (D 2 ). The NMR spectral data also disclosed the presence of two sets of aliphatic signals characteristic for 2,3-diaryldihydrobenzofuran moieties (H-7a and H-8a; H-7d and H-8d), 1-5) a sequence of four aliphatic methine protons successively coupled in this order (H-7b/H-8b/H-7c/H-8c) and a methinemethylene system (H-7e/H-8e A /H-8e B ). The 1 H-NMR spectrum measured in DMSO-d 6 exhibited signals for 10 phenolic hydroxyl groups (d H 8.98-9.58) which disappeared upon addition of D 2 O. Considering the molecular formula, the remaining three oxygens could be allotted to ether linkages. In the HMBC spectrum (Fig. ), significant 3 J correlations were observed between H-7a/C-2a(6a), H-14a/C-8a, H-7b/C-2b(6b), H-7c/C-2c(6c), H-8c/C-14c, H-7d/C-2d(6d), H-10d(14d)/C-8d and H-7e/C-2e(6e), indicating that rings A

The need for reliable, spatially and temporally consistent fluvial-sediment data has never been greater than at the present time. The traditional use of these data in the United States (U.S.) has been focused on the engineering aspects related to design and management of reservoirs and instream hydraulic structures, and on dredging. Over the last two decades, information needs have expanded to include those related to contaminated sediment management, dam decommissioning and removal, environmental quality, stream restoration, geomorphic classification and assessments, physical-biotic interactions, the global carbon budget, and legal requirements such as the U.S. Environmental Protection Agency's Total Maximum Daily Load (TMDL) Program.

Genetic Absence Epilepsy Rats from Strasbourg (GAERS) are a prognostic genetic model of absence epilepsy. This model displays the electro-clinical, behavioural, and pharmacological features of absence seizures. Although GAERS share typical characteristics, including spike-and-wave discharges (SWDs) in the electroencephalography (EEG), age-dependent studies with these animals have not yet been reported. The aim of the present study is to perform a systematic comparison contrasting the SWDs of young and older GAERS, in terms of the number, duration, frequency, and waveform morphology of the discharges, as well as the pre-SWD EEG characteristics, using identical measurement and analysis techniques. The number, cumulative total duration and mean duration of SWDs were significantly higher in young GAERS (4 to 6 months) compared to older GAERS (12 to 14 months). Furthermore, the SWD spectra and average SWD waveforms indicated that a single cycle of the SWD contains more energy in faster c...

The performance of lithium niobate (LN) photonic crystals (PhCs) is theoretically analyzed with transmission spectra and band diagrams as calculated by the 3-D Finite-Difference Time Domain (FDTD) method. For a square lattice of holes fabricated in the top surface of an Annealed Proton-Exchange (APE) waveguide, we investigate the influence of both finite hole depth and non-cylindrical hole shape, using a full treatment of the birefringent gradient index profile. As expected, cylindrical holes which are sufficiently deep to overlap the APE waveguide mode (centered at 2.5μm below the surface) produce transmission spectra closely resembling those predicted by simple 2-D modeling. As the hole depth decreases without any change in the cylindrical shape, the contrast between the photonic pass-and stop-bands and the sharpness of the band-edge are slowly lost. We show that this loss of contrast is due to the portion of the buried APE waveguide mode that passes under the holes. However, conical holes of any depth fail to produce well-defined stop-bands in either the transmission spectra or band diagrams. Deep conical holes act as a broad-band attenuator due to refraction of the mode out of the APE region down into the bulk. Experimental results confirming this observation are shown. The impact of holes which are cylindrical at the top and conical at their bottom is also investigated. Given the difficulty of fabricating high aspect-ratio cylindrical holes in lithium niobate, we propose a partial solution to improve the overlap between shallow holes and the buried mode, in which the PhC holes are fabricated at the bottom of a wide, shallow trench previously introduced into the APE waveguide surface.

In the initial steps of photosynthesis, reaction centers convert solar energy to stable charge-separated states with near-unity quantum efficiency. The reaction center from purple bacteria remains an important model system for probing the structure-function relationship and understanding mechanisms of photosynthetic charge separation. Here we perform 2D electronic spectroscopy (2DES) on bacterial reaction centers (BRCs) from two mutants of the purple bacterium , spanning the Q absorption bands of the BRC. We analyze the 2DES data using a multiexcitation global-fitting approach that employs a common set of basis spectra for all excitation frequencies, incorporating inputs from the linear absorption spectrum and the BRC structure. We extract the exciton energies, resolving the previously hidden upper exciton state of the special pair. We show that the time-dependent 2DES data are well-represented by a two-step sequential reaction scheme in which charge separation proceeds from the exc...

The aim of this study was to determine the influence of emotional expression in spectral energy distribution in professional theater actors. Study Design. The study design is a quasi-experimental study. Method. Thirty-seven actors, native Spanish speakers, were included. All subjects had at least 3 years of professional experience as a theater actor and no history of vocal pathology for the last 5 years. Participants were recorded during a read-aloud task of a 230-word passage, expressing six different emotions (happiness, sadness, fear, anger, tenderness, and eroticism) and without emotion (neutral state). Acoustical analysis with long-term average spectrum included three variables: the energy level difference between the F 1 and fundamental frequency (F 0 ) regions, ratio between 1-5 kHz and 5-8 kHz, and alpha ratio. Results. All the different emotions differ significantly from the neutral state for alpha ratio and 1-5/5-8 kHz ratio. Only significant differences between ''joy,'' ''anger,'' and ''eroticism'' were found for L1-L0 ratio. Statistically significant differences between genders for the three acoustical variables were also found. Conclusion. The expression of emotion impacts the spectral energy distribution. On the one hand emotional states characterized by a breathy voice quality such as tenderness, sadness, and eroticism present a low harmonic energy above 1 kHz, high glottal noise energy, and more energy on F 0 than overtones. On the other hand, emotional states such as joy, anger, and fear are characterized by high harmonic energy greater than 1 kHz (less steep spectral slope declination), low glottal noise energy, and more energy on the F 1 than F 0 region.

The phosphatase CDC25B is one of the key regulators that control entry into mitosis through the dephosphorylation and subsequent activation of the cyclin-dependent kinases. Here we study the phosphorylation of CDC25B at mitosis by the kinase pEg3, a member of the KIN1/PAR-1/MARK family. Using mass spectrometry analysis we demonstrate that CDC25B is phosphorylated in vitro by pEg3 on serine 169, a residue that lies within the B domain. Moreover, using phosphoepitope-specific antibodies we show that serine 169 is phosphorylated in vivo, that this phosphorylated form of CDC25B accumulates during mitosis, and is localized to the centrosomes. This labelling is abrogated when pEg3 expression is repressed by RNA interference. Taken together, these results support a model in which pEg3 contributes to the control of progression through mitosis by phosphorylation of the CDC25 phosphatases. www.landesbioscience.com Cell Cycle 811 CDC25B Phosphorylated by pEg3 Localizes to the Centrosome and the Spindle Poles at Mitosis

We detected temporal changes of crustal structure by cross spectrum analyses of seismic waves excited by two artificial explosions that were carried out about one month before and two months after a M6.1 shallow earthquake. Phase spectrum analysis shows that seismic velocity of the upper crust around the focal area of the M6.1 earthquake and Mount lwate decreased 0.3 -1.0 % during the three months. Since lager decreases of the seismic velocity were observed at the region close to the focal area and a volcanic pressure source, we conclude that stress change in the upper crust is a most plausible candidate to cause the velocity changes among other candidates. We further apply a coherence analysis to the observed seismic coda to locate regions where shortwavelength heterogeneity temporally changed. The result indicates a possibility of temporal changes of the heterogeneity beneath the volcano, where a magmatic fluid intrusion is inferred.

A new technique for high resolution photoacoustic detection based on application of laser diodes has been developed. This method was tested and compared using identical photoacoustic instrumentation (cell and microphone) to study gas absorption in three different spectral regions, namely: the infrared range near 2100 cm 21 , CO and OCS fundamental band absorption; the ranges near 4200 and 4350 cm 21 , CH 4, NH 3 and N 2 O overtone and combination band absorption; the near infrared range near 6500 cm 21 , CO, CO 2 and NH 3 overtone absorption. Several types of diode laser operating at room temperature or at liquid nitrogen temperature were compared. The optimum gas pressures for the maximum sensitivity of the photoacoustic signals were found and the detection limits were estimated for all of the gases studied. The best sensitivity was achieved for NH 3 at 100 ppbv. The sensitivity of the developed system was tested on detection of traces of NH 3 and CO 2 gases from car exhaust. a

Exposure of the retina of the rhesus monkey to visible and infrared radiation from CW optical sources like the Sun, xenon lamps, etc. produces small lesions or scotomata which may be classified as thermal or photochemical, depending on the wavelength and duration of exposure. The action spectrum for the production of retinal lesions has been determined for eight monochromatic laser wavelengths extending from 1064 to 441 nm. The corneal power required to produce a lesion decreases by three orders of magnitude in going from 1064 to 441 nm. Exposure to 1064 nm radiation for 1000 s produces a typical thermal lesion at elevated retinal temperatures, whereas a 1000 s exposure to 441 nm light produces a photochemical lesion at power levels too low to raise the retinal temperature by an appreciable amount ( < O.l°C). The two types of lesion have entirely different characteristics as will be discussed in some detail. The photopathology of the photochemical lesion has been studied at postexposure times ranging from 1 h to 90 days and will be demonstrated in a number of histological slides. Moreover, this photopathology correlates well with monocular visual acuity tests in the rhesus monkey as defined by the Landolt ring technique. To further elucidate the differential effects on the retina of short vs long wavelength CW radiation, we have divided a simulated solar spectrum at sea level into two spectral bands, 400--800 nm and 700-1400 nm, and determined the radiant• exposures required to produce very mild lesions on the rhesus retina for exposure times of 1, 10, 100 and 1000 s. To correlate our data with solar retinitis and eclipse blindness the image diameter or spot size on the retina was 159 11m, corresponding to the image size of the Sun on the human retina. Exposure to the 400--800 nm spectrum for durations of 10 s or greater required approximately 400 J/cm 2 to produce a mild photochemical lesion. Reciprocity is maintained over the exposure range 10--1000 s . . Radiant exposure to the 700-1400 nm spectrum, on the other hand, required roughly 69,100 J/cm 2 for a 1000 s exposure. This was a mild thermal lesion. We were unable to produce .a lesion for exposure times less than 1000 s. We interpret these data to mean that solar retinitis and eclipse blindness are primarily photochemical events produced by the short wavelength component of the solar spectrum, and that the infrared component of the solar spectrum plays only a minor role in these retinal pathologies.

We report the first science results from the Space Environment Viability of Organics (SEVO) payload aboard the Organism/Organic Exposure to Orbital Stresses (O/OREOS) free-flying nanosatellite, which completed its nominal spaceflight mission in May 2011 but continues to acquire data biweekly. The SEVO payload integrates a compact UV-visible-NIR spectrometer, utilizing the Sun as its light source, with a 24-cell sample carousel that houses four classes of vacuum-deposited organic thin films: polycyclic aromatic hydrocarbon (PAH), amino acid, metalloporphyrin, and quinone. The organic films are enclosed in hermetically sealed sample cells that contain one of four astrobiologically relevant microenvironments. Results are reported in this paper for the first 309 days of the mission, during which the samples were exposed for *2210 h to direct solar illumination (*1080 kJ/cm 2 of solar energy over the 124-2600 nm range). Transmission spectra (200-1000 nm) were recorded for each film, at first daily and subsequently every 15 days, along with a solar spectrum and the dark response of the detector array. Results presented here include eight preflight and 16 in-flight spectra of eight SEVO sample cells. Spectra from the PAH thin film in a water-vapor-containing microenvironment indicate measurable change due to solar irradiation in orbit, while three other nominally water-free microenvironments show no appreciable change. The quinone anthrarufin showed high photostability and no significant spectroscopically measurable change in any of the four microenvironments during the same period. The SEVO experiment provides the first in situ real-time analysis of the photostability of organic compounds and biomarkers in orbit.

We have developed a portable, breast margin assessment probe leveraging diffuse optical spectroscopy to quantify the morphological landscape of breast tumor margins during breast conserving surgery. The approach presented here leverages a custom-made 16-channel annular photodiode imaging array (arranged in a 4 × 4 grid), a raster-scanning imaging platform with precision pressure control, and compressive sensing with an optimized set of eight wavelengths in the visible spectral range. A scalable Monte-Carlo-based inverse model is used to generate optical property [ ? s ? ( ? ) and ? a ( ? ) ] measures for each of the 16 simultaneously captured diffuse reflectance spectra. Subpixel sampling (0.75 mm) is achieved through incremental x , y raster scanning of the imaging probe, providing detailed optical parameter maps of breast margins over a 2 × 2 ?? cm 2 area in ? 9 ?? min . The morphological landscape of a tumor margin is characterized using optical surrogates for the fat to fibrogla...

Plasmas were created by exploding 7000 A thick CH foils at the irradiation conditions: 1.064 ..mu..m, 3 kJ, 2.5 x 10/sup 15/ W/cm/sup 2/, 900 ps FWHM, 400 ..mu..m spot diameter. Ten percent of the laser energy appeared as Raman light and 0.04% as 3..omega../sub 0//2 light. The 3..omega../sub 0//2 light and the 30-70 keV X rays occurred simultaneouly at t=-120/sup +50//sub -//sub 200/ psec and lasted only 300 psec FWHM. The foil was calculated to explode to n/sub c/4 at t=-300 psec. The spectrum and angular distribution of the Raman light were also measured. Time-resolved spectral measurements have been made in experiments with 5320 A laser light in a 600-900 psec FWHM pulse. The scaling of the 3..omega../sub 0//2 light with both the laser spot size and pulse length has been studied.

Shakila and Kalainathan report on the synthetic and structural aspects of a zinc iodide complex with Schiff based ligand, which exhibits room temperature ferromagnetism. In this comment, many points of criticism, concerning the characterization of this so called zinc iodide complex of Schiff based ligand are highlighted to prove that the title paper is completely erroneous.

We report investigations of HDO and H 2 O on Mars using CSHELL at the NASA IRTF for seasonal dates that span the entire Mars year. Our objective is to obtain measurements of the seasonal and latitudinal variation of the [HDO]/[H 2 O] ratio and thereby obtain better insights into the dynamics of Mars' atmosphere. The instrument slit is typically positioned N-S along the central meridian resulting in a one-dimensional map of HDO (1997HDO ( -2006) ) and/or H 2 O (2001-2006) [1]. Column densities are extracted at intervals between 0.6 and 1.0 arc-second; [HDO]/[H 2 O] ratios are calculated for various latitudes and seasons.

Living systems produce more than 90% of Earth&#39;s atmospheric methane; the balance is of geochemical origin. On Mars, methane could be a signature of either origin. Using high-dispersion infrared spectrometers at three ground-based telescopes, we measured methane and water vapor simultaneously on Mars over several longitude intervals in northern early and late summer in 2003 and near the vernal equinox in 2006. When present, methane occurred in extended plumes, and the maxima of latitudinal profiles imply that the methane was released from discrete regions. In northern midsummer, the principal plume contained ∼19,000 metric tons of methane, and the estimated source strength (≥0.6 kilogram per second) was comparable to that of the massive hydrocarbon seep at Coal Oil Point in Santa Barbara, California.

The human circadian pacemaker maintains timing and consolidation of sleep-wake behavior by opposing the build-up of homeostatic sleep pressure during the wake episode, particularly in the evening during the 'wake maintenance zone'. We tested whether age-related changes in sleep are a consequence of a weaker circadian arousal signal in the evening. Circadian rhythms and spectral components of the sleep EEG were investigated in 17 young (20-31 year) and 15 older (57-74 year) volunteers under constant posture conditions during a 40-h nap protocol (75/150 min sleep/wake schedule). Quantitative evidence for a weaker circadian arousal signal in aging arose from significantly more sleep occurring during the wake maintenance zone and higher subjective sleepiness ratings in the late afternoon and evening in the older group. In addition, we found a diminished melatonin secretion and a reduced circadian modulation of REM sleep together with less pronounced day-night differences in the lower alpha and spindle range of sleep EEG activity in the older group. Thus, our data indicate that age-related changes in sleep propensity are clearly related to a reduced circadian signal opposing the homeostatic drive for sleep.

The benefits of the use of organic wastes as fertilizers and soil amendments should be assessed together with potential environmental and toxicological impacts due to the presence of trace metallic elements. The knowledge of metallic trace elements speciation is essential to fully understand their behavior after spreading of organic wastes and to predict their bioavailability. The present work was aimed at studying speciation of copper in various organic wastes (sewage sludge and composts from municipal solid waste and animals manure), which exhibit moderate to high levels of copper (24 to 340 mg kg dry matter) and are commonly used in several countries as fertilizer or soil amendment (Saint Denis-La Reunion-France, Mahajanga-Magacascar, Dakar-Senegal). Size fractionation was first performed to account for the complexity of wastes and X-ray absorption spectroscopy (XAS) will be combined with different analytical approaches to determine speciation. Organic wastes exhibited a fairly l...

Applications of so-called organic wastes are recommended in agricultural fields where soil organic matter content is low. However, these materials could pose some hazard to humans, animals, or to the environment through the assessment of the dynamic of potential pollutants such as trace metals. This study thus aimed at evaluating the speciation of copper (Cu) and zinc (Zn) in various organic wastes exhibiting moderate to high levels of trace metals, their dynamic in a soil after amendment and their mutual correlation. Trace metals speciation was determined by X-ray absorption spectroscopy (XAS) while the temporal dynamic remobilization in soil/waste mixtures was monitored using the diffusive gradient in thin films (DGT) technique. Results indicated that predominant pools of species in wastes were inorganic for Zn (&gt;60%) and organic for Cu (&gt;50%). During mineralization, we detected an increase in the remobilization of trace elements in soil/waste mixtures, which was more notice...

While beta oscillations often occur within the parkinsonian basal ganglia, how these oscillations emerge from a naive state and change with disease severity is not clear. To address this question, a progressive, nonhuman primate model of Parkinson's disease was developed using staged injections of MPTP. Within each parkinsonian state (naive, mild, moderate, and severe), spontaneous local field potentials were recorded throughout the sensorimotor globus pallidus. In the naive state, beta oscillations (11-32 Hz) occurred in half of the recordings, indicating spontaneous beta oscillations in globus pallidus are not pathognomonic. Mild and moderate states were characterized by a narrower distribution of beta frequencies that shifted toward the 8 -15 Hz range. Additionally, coupling between the phase of beta and the amplitude of highfrequency oscillations (256 -362 Hz) emerged in the mild state and increased with severity. These findings provide a novel mechanistic framework to understand how progressive loss of dopamine translates into abnormal information processing in the pallidum through alterations in oscillatory activity. The results suggest that rather than the emergence of oscillatory activity in one frequency spectrum or the other, parkinsonian motor signs may relate more to the development of altered coupling across multiple frequency spectrums.

The Ames Vertical Gun Range (AVGR) is a national facility for conducting laboratory- scale investigations of high-speed impact processes. It provides a set of light-gas, powder, and compressed gas guns capable of accelerating projectiles to speeds up to 7 km s(exp -1). The AVGR has a unique capability to vary the angle between the projectile-launch and gravity vectors between 0 and 90 deg. The target resides in a large chamber (diameter approximately 2.5 m) that can be held at vacuum or filled with an experiment-specific atmosphere. The chamber provides a number of viewing ports and feed-throughs for data, power, and fluids. Impacts are observed via high-speed digital cameras along with investigation-specific instrumentation, such as spectrometers. Use of the range is available via grant proposals through any Planetary Science Research Program element of the NASA Research Opportunities in Space and Earth Sciences (ROSES) calls. Exploratory experiments (one to two days) are additiona...

The US cotton industry wants to increase its market share and value throughout the world by supplying pure cotton. Removing contamination requires developing a means to detect plastics in seedcotton. This study was conducted to determine if ion mobility spectrometry (IMS) could be used to find small amounts of plastic in a matrix of heated seedcotton. Commercial IMS analyzers equipped with membrane inlets sampled air displaced from heated flasks containing seedcotton and five common plastic contaminants: bale twine, new and weathered polypropylene tarp, polyethylene film, and plastic film shopping bags. In the first of two sets of experiments the temperature was varied from 85 to 115 °C to determine its influence on vapor emissions; in the second, air samples were taken from seedcotton containing various amounts of each plastic. Vapors from plastics associated with cotton contamination were detected with IMS in negative polarity; different plastics were distinctive. Vapor molecules and product ions from plastics and seedcotton both increased with temperature. Seedcotton vapors spectra coincided with plastics vapors spectra but had different slope characteristics at specific drift times. Digital signal processing may be used to detect plastic contamination, triggering an alarm or control action. Spectra from new and old polypropylene tarp were nearly identical suggesting detection will be possible after weathering. IMS detection of plastics vapors in seedcotton works in the laboratory. The next step is developing IMS systems for commercial cotton gins.

Superoxide reductases (SORs) are small metalloenzymes, which catalyze reduction of O 2 .-to H 2 O 2 . The reaction of the enzyme from Treponema pallidum with superoxide was studied by pulse radiolysis methods. The first step is an extremely fast bi-molecular reaction of the ferrous center with O 2 .-, with a rate constant of 6x10 8 M -1 s -1 . A first intermediate is formed which is converted to a second one with a slower rate constant of 4800 s -1 . This latter value is 10 times higher than the corresponding one previously reported in the case of SOR from Desulfoarculus baarsii. The reconstituted spectra for the two intermediates are consistent with formation of transient iron-peroxide species.

The photophysics of Safranine-O (3,6-diamino-2,7-dimethyl-5 phenyl phenazinium chloride) (SfH + Cl -) was investigated in reverse micelles (RMs) of AOT (sodium bis(2-ethylhexyl)sulfosuccinate) with special emphasis on the triplet state processes. The triplet is formed in its monoprotonated form, independently of the pH of the water used to prepare the RMs. While the intersystem crossing quantum yields in RMs are similar to those in organic solvents, the triplet lifetime is much longer. Since the pH in the water pool of AOT RMs is close to 5 and the triplet state of the dye is subjected to proton quenching, the long lifetime indicates that the dye resides in a region where it cannot be reached by protons during its lifetime. All the measurements indicate that the dye is localized in the interface, sensing a medium of micropolarity similar to EtOH : water (3 : 1) mixtures. The quenching by aliphatic amines was also investigated. While the quenching by the hydrophobic tributylamine is similar to that in methanol, the hydro-soluble triethanolamine is one order of magnitude more effective in RMs than in homogeneous solution. In the latter case the quenching process is interpreted by a very fast intramicellar quenching, the overall kinetics being controlled by the exchange of amine molecules between RMs. Semireduced dye is formed in the quenching process in RMs in the di-protonated state with a comparable quantum yield to the monoprotonated state formed in homogeneous solvents. The results point to the advantage of the reverse micellar system for the generation of active radicals for the initiation of vinyl polymerization, since a much lower concentration of amine can be employed with similar quantum yields.

Neurological insults during development are associated with later impairments in learning and memory. Although remedial training can help restore cognitive function, the neural mechanisms of this recovery in memory systems are largely unknown. To examine this issue, we measured electrophysiological oscillatory activity in the hippocampus (both CA3 and CA1) and prefrontal cortex of adult rats that had experienced repeated seizures in the first weeks of life, while they were remedially trained on a delayed-nonmatch-to-sample memory task. Seizure-exposed rats showed initial difficulties learning the task but performed similarly to control rats after extra training. Whole-session analyses illustrated enhanced theta power in all three structures while seizure rats learned response tasks before the memory task. While performing the memory task, dynamic oscillation patterns revealed that prefrontal cortex theta power was increased among seizure-exposed rats. This enhancement appeared after the first memory-training steps using short delays and plateaued at the most difficult steps, which included both short and long delays. Further, seizure rats showed enhanced CA1-prefrontal cortex theta coherence in correct trials compared with incorrect trials when long delays were imposed, suggesting increased hippocampal-prefrontal cortex synchrony for the task in this group when memory demand was high. Seizure-exposed rats also showed heightened gamma power and coherence among all three structures during the trials. Our results demonstrate the first evidence of hippocampal-prefrontal enhancements following seizures in early development. Dynamic compensatory changes in this network and interconnected circuits may underpin cognitive rehabilitation following other neurological insults to higher cognitive systems.

Neurological insults during development are associated with later impairments in learning and memory. Although remedial training can help restore cognitive function, the neural mechanisms of this recovery in memory systems are largely unknown. To examine this issue, we measured electrophysiological oscillatory activity in the hippocampus (both CA3 and CA1) and prefrontal cortex of adult rats that had experienced repeated seizures in the first weeks of life, while they were remedially trained on a delayed-nonmatch-to-sample memory task. Seizure-exposed rats showed initial difficulties learning the task but performed similarly to control rats after extra training. Whole-session analyses illustrated enhanced theta power in all three structures while seizure rats learned response tasks before the memory task. While performing the memory task, dynamic oscillation patterns revealed that prefrontal cortex theta power was increased among seizure-exposed rats. This enhancement appeared after...

A new and compact photoacoustic sensor for trace gas detection in the 2-2.5 m atmospheric window is reported. Both the development of antimonide-based DFB lasers with singlemode emission in this spectral range and a novel design of photoacoustic cell adapted to the characteristics of these lasers are discussed. The laser fabrication was made in two steps. The structure was firstly grown by molecular beam epitaxy then a metallic DFB grating was processed. The photoacoustic cell is based on a Helmholtz resonator that was designed in order to fully benefit from the highly divergent emission of the antimonide laser. An optimized modulation scheme based on wavelength modulation of the laser source combined with second harmonic detection has been implemented for efficient suppression of wall noise. Using a 2211 nm laser, sub-ppm detection limit has been demonstrated for ammonia.

No Methane to Be Found On Earth, atmospheric methane is mostly produced biologically. Atmospheric methane has also been detected on Mars, but these reports have been controversial. Based on data from the Sample Analysis at Mars instrument suite on the Curiosity rover, which arrived at the surface of Mars in August 2012, Webster et al. (p. 355 , published online 19 September) report no methane, with an upper limit of only 1.3 parts per billion by volume, about 6 times lower than previous measurements.