Optical Imaging

This paper presents galaxy source counts at 24 microns in the six Spitzer Wide-field InfraRed Extragalactic (SWIRE) fields. The source counts are compared to counts in other fields, and to model predictions that have been updated since the launch of Spitzer. This analysis confirms a very steep rise in the Euclidean-normalized differential number counts between 2 mJy and 0.3 mJy. Variations in the counts between fields show the effects of sample variance in the flux range 0.5-10 mJy, up to 100% larger than Poisson errors. Nonetheless, a “shoulder ” in the normalized counts persists at around 3 mJy. The peak of the normalized counts at 0.3 mJy is higher and narrower than most models predict. In the ELAIS N1 field, the 24 micron data are combined with Spitzer-IRAC data and five-band optical imaging, and these bandmerged data are fit with photometric redshift templates. Above 1 mJy the counts are dominated by galaxies at z < 0.3. By 300 microJy, about 25 % are between z ∼0.3-0.8, and...

Electrochemically active bacteria (EAB) on the cathodes of microbial fuel cells (MFCs) can remove metals from the catholyte, but the fate of metals in the cells has not been examined in the presence of multiple metals. To study the relative uptake and fate of Cr(VI) and Cd(II) in cells, fluorescence probes were used to determine the amount and location of these metals in four different EAB on the biocathodes of MFCs. When both metals were present, less Cr(VI) was removed but Cd(II) uptake was not appreciably affected. As a consequence, the imaging of Cr(III) ions was lower than that using individual fluorescence probes for single Cr(III) ions in each EAB, compared to negligible changes in images for Cd(II) ions in the presence of either both Cr(VI) and Cd(II) or Cd(II) alone. The concentration of Cr(III) ions in the cells consistently increased over time, while that of Cd(II) ions decreased following an initial increase. Cr or Cd uptake could not be detected using a scanning electro...

The present paper reports the semiconducting Ag 2 S (silver sulphide) thin films were grown on the glass substrate by means of chemical bath deposition method (CBD). Films deposited at the 60 0 in bath containing aqueous solution of silver acetate , thiourea, TEA and ammonia. Silver acetate for silver ion source, thiourea for sulphur ion source, TEA is the complexing agent and ammonia for pH. Photocurrent,Dark current, excitation behavior and photoconductivity rise and decay studies has been done. In the excitation spectra photocurrent exist with the visible wavelength light. Quite good photosensitivity is observed in silver sulphide thin films. INTRODUCTION Silver sulphide is the sulphide of silver. This dense black solid constitutes the tarnish that forms over time on silver ware and other silver objects. Silver sulphide is insoluble in all solvents, but is degraded by strong acids. When formed on electrical contacts operating in an atmosphere rich in hydrogen sulphide, long filam...

We found that using more than one parameter derived from optical tomographic images can lead to better image classification results compared to cases when only one parameter is used.. In particular we present a multi-parameter classification approach, called self-organizing mapping (SOM), for detecting synovitis in arthritic finger joints based on sagittal laser optical tomography (SLOT). This imaging modality can be used to determine various physical parameters such as minimal absorption and scattering coefficients in an image of the proximal interphalengeal joint. Results were compared to different gold standards: magnet resonance imaging, ultra-sonography and clinical evaluation. When compared to classifications based on single-parameters, e.g., absorption minimum only, the study reveals that multiparameter classifications lead to higher classification sensitivities and specificities and statistical significances with pvalues <5 per cent. Finally, the data suggest that image analyses are more reliable and avoid ambiguous interpretations when using more than one parameter.

Muscle damage is currently assessed through methods such as muscle biopsy, serum biomarkers, functional testing, and imaging procedures, each with its own inherent limitations, and a pressing need for a safe, repeatable, inexpensive, and noninvasive modality to assess the state of muscle health remains. Our aim was to develop and assess near-infrared (NIR) optical imaging as a novel noninvasive method of detecting and quantifying muscle damage. An immobilizationereambulation model was used for inducing muscle damage and recovery in the lower hindlimbs in mice. Confirmation of muscle damage was obtained using in vivo indocyanine greeneenhanced NIR optical imaging, magnetic resonance imaging, and ex vivo tissue analysis. The soleus of the immobilizedereambulated hindlimb was found to have a greater amount of muscle damage compared to that in the contralateral nonimmobilized limb, confirmed by in vivo indocyanine greeneenhanced NIR optical imaging (3.86-fold increase in radiant efficiency), magnetic resonance imaging (1.41-fold increase in T 2 ), and an ex vivo spectrophotometric assay of indocyanine green uptake (1.87-fold increase in normalized absorbance). Contrast-enhanced NIR optical imaging provides a sensitive, rapid, and noninvasive screening method that can be used for imaging and quantifying muscle damage and recovery in vivo.

Muscle damage is currently assessed through methods such as muscle biopsy, serum biomarkers, functional testing, and imaging procedures, each with its own inherent limitations, and a pressing need for a safe, repeatable, inexpensive, and noninvasive modality to assess the state of muscle health remains. Our aim was to develop and assess near-infrared (NIR) optical imaging as a novel noninvasive method of detecting and quantifying muscle damage. An immobilizationereambulation model was used for inducing muscle damage and recovery in the lower hindlimbs in mice. Confirmation of muscle damage was obtained using in vivo indocyanine greeneenhanced NIR optical imaging, magnetic resonance imaging, and ex vivo tissue analysis. The soleus of the immobilizedereambulated hindlimb was found to have a greater amount of muscle damage compared to that in the contralateral nonimmobilized limb, confirmed by in vivo indocyanine greeneenhanced NIR optical imaging (3.86-fold increase in radiant efficiency), magnetic resonance imaging (1.41-fold increase in T 2 ), and an ex vivo spectrophotometric assay of indocyanine green uptake (1.87-fold increase in normalized absorbance). Contrast-enhanced NIR optical imaging provides a sensitive, rapid, and noninvasive screening method that can be used for imaging and quantifying muscle damage and recovery in vivo.

This paper presents a novel method of multi-spatial light modulator (SLM) holographic image display that enables wide angle reconstruction of images of real world objects. The image data are delivered by means of digital holography. The capture and display systems are arranged in a circular configuration. In order to support the proper information flow between the multi-sensor capture and multi-SLM display systems we perform analysis using the Wigner distribution function. We also consider a mismatch of the capture and display configurations as well as the visual perception of the displayed image. Experimental results based on the reconstruction of real world scenes are presented that demonstrate the validity of the theoretical solutions. A single camera is used to record the digital holograms, where the object is rotated between captures, and these holograms are then displayed on a circular configuration of SLMs. The results show the limitation of multi-SLM holographic displays in terms of visual perception. These problems arise from the limited angular distribution of the SLMs on a display circle and the presence of gaps between the SLMs.

A strain-sensing lyriform organ (HS-10) found on all of the legs of a Central American wandering spider (Cupiennius salei) detects courtship, prey and predator vibrations transmitted by the plant on which it sits. It has been suggested that the viscoelastic properties of a cuticular pad directly adjacent to the sensory organ contribute to the organ&#39;s pronounced high-pass characteristics. Here, we investigate the micromechanical properties of the cuticular pad biomaterial in search of a deeper understanding of its impact on the function of the vibration sensor. These properties are considered to be an effective adaptation for the selective detection of signals for frequencies &gt;40 Hz. Using surface force spectroscopy mapping we determine the elastic modulus of the pad surface over a temperature range of 15-40 °C at various loading frequencies. In the glassy state, the elastic modulus was ~100 MPa, while in the rubbery state the elastic modulus decreased to 20 MPa. These data ar...

Root systems develop different root types that individually sense cues from their local environment and integrate this information with systemic signals. This complex multi-dimensional amalgam of inputs enables continuous adjustment of root growth rates, direction and metabolic activity that define a dynamic physical network. Current methods for analyzing root biology balance physiological relevance with imaging capability. To bridge this divide, we developed an integrated imaging system called Growth and Luminescence Observatory for Roots (GLO-Roots) that uses luminescence-based reporters to enable studies of root architecture and gene expression patterns in soil-grown, light-shielded roots. We have developed image analysis algorithms that allow the spatial integration of soil properties such as soil moisture with root traits. We propose GLO-Roots as a system that has great utility in presenting environmental stimuli to roots in ways that evoke natural adaptive responses and in pro...

We report the discovery of kinematic shock signatures associated with a localized radio jet interaction in the merging Seyfert galaxy NGC 5929. We explore the velocity-dependent ionization structure of the gas and find that low ionization gas at the interaction site is significantly more disturbed than high ionization gas, which we attribute to a local enhancement of shock ionization due to the influence of the jet. The characteristic width of the broad low-ionization emission is consistent with shock velocities predicted from the ionization conditions of the gas. We interpret the relative prominence of shocks to the high density of gas in nuclear environment of the galaxy and place some constraints of their importance as feedback mechanisms in Seyferts.

For the past 10 years there has been an active debate over whether fast shocks play an important role in ionizing emission line regions in Seyfert galaxies. To investigate this claim, we have studied the Seyfert 2 galaxy Mkn 78, using HST UV/optical images and spectroscopy. Since Mkn 78 provides the archetypal jet-driven bipolar velocity field, if shocks are important anywhere they should be important in this object. Having mapped the emission line fluxes and velocity field, we first compare the ionization conditions to standard photoionization and shock models. We find coherent variations of ionization consistent with photoionization model sequences which combine optically thick and thin gas, but are inconsistent with either autoionizing shock models or photoionization models of just optically thick gas. Furthermore, we find absolutely no link between the ionization of the gas and its kinematic state, while we do find a simple decline of ionization degree with radius. We feel this object provides the strongest case to date against the importance of shock related ionization in Seyferts.

Space-based Telescopes for Actionable Refinement of Ephemeris (STARE) is a nano-sat based mission designed to better determine the trajectory of satellites and space debris in orbit around earth. In this paper, we give a brief overview of the mission and its place in the larger context of Space Situational Awareness (SSA). We then describe the details of the central optical payload, touching on the optical design and characterization of the on-board image sensor used in our Cubesat based prototype. Finally, we discuss the on-board star and satellite track detection algorithm central to the success of the mission.

Evolution of the hydrogen incidence rate and mass density of damped Lyman-α systems out to z~5 2 Absorption line measurements provide a unique laboratory to study the production, transport, evolution, and distribution of metals in the intergalactic medium (IGM) and circumgalactic medium (CGM) of galaxies in the early universe. Damped Ly-alpha systems (DLAs) dominate the neutral gas content of the Universe and enable some of the most robust metallicity measurements of high redshift gas. We present the initial results of a Very Large Telescope (VLT) X-Shooter survey of 41 5.0 < z < 5.6 quasars used to measure the neutral hydrogen (HI) gas mass density at the highest possible redshifts. Combining this new sample with previously published samples at lower redshifts, we investigate the evolution of these neutral hydrogen gas reservoirs and find that the incidence rate and HI mass density are both observed to increase out to z~4, and then to decrease at z~5. These results tightly constrain simulations of galaxy formation and evolution.

carrier relaxation pathways in individual semiconductor nanowires (NWs) is crucial, since the geometry of these nanostructures can significantly influence carrier recombination and trapping. In particular, GaN NWs are promising wide bandgap semiconductors for applications in nanophotonics, but the efficiency and lifetime of GaN-based devices are largely affected by the presence of structural and point defects. In this study we employ wavelengthtunable femtosecond optical pump-probe spectroscopy to study carrier relaxation through the defect states responsible for yellow luminescence in both a single GaN NW and NW ensembles. These are the first ultrafast optical experiments on single group III-V NWs, revealing spatially resolved carrier dynamics along the length of an individual wire.

Intrinsic fluorescence spectra of the human normal, cervical intraepithelial neoplasia 1 (CIN1), CIN2, and cervical cancer tissue have been extracted by effectively combining the measured polarized fluorescence and polarized elastic scattering spectra. The efficacy of principal component analysis (PCA) to disentangle the collective behavior from smaller correlated clusters in a dimensionally reduced space in conjunction with the intrinsic fluorescence is examined. This combination unambiguously reveals the biochemical changes occurring with the progression of the disease. The differing activities of the dominant fluorophores, collagen, nicotinamide adenine dinucleotide, flavins, and porphyrin of different grades of precancers are clearly identified through a careful examination of the sectorial behavior of the dominant eigenvectors of PCA. To further classify the different grades, the Mahalanobis distance has been calculated using the scores of selected principal components.

Physicists often cite single-photon detectors as proof that photons are indivisible particles: one photon in, one discrete click out. We show this is a misinterpretation. Photons are finite electromagnetic packets that always deposit their full energy at a localized site. The apparent discreteness of detection is an artifact of avalanche multiplication and quenching in devices such as photomultiplier tubes (PMTs) and single-photon avalanche diodes (SPADs). In short: the detectors are digital, not the field. 3. Multi-photon absorption within a single avalanche window still yields one click (saturation), contradicting naive particle-counting interpretations. VI. CONCLUSION PMTs and SPADs demonstrate that finite photon packets always deposit their energy at a point. The apparent discreteness is a consequence of avalanche multiplication and thresholding, not a proof of particle ontology. The detector is digital; the field is not. Recognizing this resolves the long-standing misinterpretation and aligns photon detection with Maxwellian field physics.

The cRGD peptide is a promising probe for early non-invasive detection of tumors. This study aimed to demonstrate how RAFT-c(-RGDfK-) 4 , a molecule allowing a tetrameric presentation of cRGD, improved cRGD-targeting potential using in vivo models of α V β 3 -positive or negative tumors. We chose the human embryonic kidney cells HEK293(β 3 ) (high levels of α V β 3 ) or HEK293(β 1 ) (α V β 3 -negative but expressing α V and β1) engrafted subcutaneously (s.c.) in mice. Non-invasive in vivo optical imaging demonstrated that as compared to its monomeric cRGD analogue, Cy5-RAFT-c(-RGDfK-) 4 injected intravenously had higher uptake, prolonged retention and markedly enhanced contrast in HEK293(β 3 ) than in the HEK293(β 1 ) tumors. Blocking studies further demonstrated the targeting specificity and competitive binding ability of the tetramer. In conclusion, we demonstrated that Cy5-RAFT-c(-RGDfK-) 4 was indeed binding to the α V β 3 receptor and with an improved activity as compared to its monomeric analog, confirming the interest of using multivalent ligands. Intravenous injection of Cy5-RAFT-c(-RGDfK-) 4 in this novel pair of HEK293(β 3 ) and HEK293(β 1 ) tumors, provided tumor/skin ratio above 15. Such an important contrast plus the opportunity to use the HEK293(β 1 ) negative control cell line are major assets for the community of researchers working on the design and amelioration of RGD-targeted vectors or on RGD-antagonists.

The cRGD peptide is a promising probe for early non-invasive detection of tumors. This study aimed to demonstrate how RAFT-c(-RGDfK-) 4 , a molecule allowing a tetrameric presentation of cRGD, improved cRGD-targeting potential using in vivo models of α V β 3 -positive or negative tumors. We chose the human embryonic kidney cells HEK293(β 3 ) (high levels of α V β 3 ) or HEK293(β 1 ) (α V β 3 -negative but expressing α V and β1) engrafted subcutaneously (s.c.) in mice. Non-invasive in vivo optical imaging demonstrated that as compared to its monomeric cRGD analogue, Cy5-RAFT-c(-RGDfK-) 4 injected intravenously had higher uptake, prolonged retention and markedly enhanced contrast in HEK293(β 3 ) than in the HEK293(β 1 ) tumors. Blocking studies further demonstrated the targeting specificity and competitive binding ability of the tetramer. In conclusion, we demonstrated that Cy5-RAFT-c(-RGDfK-) 4 was indeed binding to the α V β 3 receptor and with an improved activity as compared to its monomeric analog, confirming the interest of using multivalent ligands. Intravenous injection of Cy5-RAFT-c(-RGDfK-) 4 in this novel pair of HEK293(β 3 ) and HEK293(β 1 ) tumors, provided tumor/skin ratio above 15. Such an important contrast plus the opportunity to use the HEK293(β 1 ) negative control cell line are major assets for the community of researchers working on the design and amelioration of RGD-targeted vectors or on RGD-antagonists.

Planetary systems come in a bewildering variety of shapes and sizes. In addition to the exoplanetary systems with giant planets, found in surveys of stellar radial velocity variations, an overlapping class of dusty disk-containing solar systems exists. The disks include large quantities of meteoroids and dust, and a varying complement of gas. Their solid material represents 'replenished' dust born in the collisions/sublimation of planetesimals perturbed by planets. We present several such systems, including HR 4796A, HD 141569, HD 100546, and the prototypical replenished disk of Beta Pictoris. We discuss the composition, physical processing, and migration of dust in the disks, their evolutionary status, and the evidence of embedded planets.

We analyze the dynamics of gas-dust coupling in the presence of stellar radiation pressure in circumstellar disks, which are in a transitional stage between the gas-dominated, optically thick, primordial nebulae, and the dust-dominated, optically thin Vega-type disks. Meteoroids and dust undergo radial migration, either leaving the disk due to a strong radiation pressure, or seeking a stable equilibrium orbit in corotation with gas. In our models of A-type stars surrounded by a total gas mass from a fraction to dozens of Earth masses, the outward migration speed of dust is comparable with the gas sound speed. Equilibrium orbits are circular, with exception of those significantly affected by radiation pressure, which can be strongly elliptic with apocenters extending beyond the bulk of the gas disk. The migration of dust gives rise to radial fractionation of dust and creates a variety of possible observed disk morphologies, which we compute by considering the equilibrium between the dust production (at radii 10AU) and the dust-dust collisions removing particles from their equilibrium orbits. Sand-sized and larger grains are distributed throughout most of the disk, with concentration near the gas pressure maximum in the inner disk. Smaller grains (typically in the range of 10 to 200µm) concentrate in a prominent ring structure in the outer region of the gas disk (presumably at radius ∼100 AU), where gas density is rapidly declining with radius. The width and density, as well as density contrast of the dust ring with respect to the inner dust disk depend on the distribution of gas and the mechanical strength of the particles, but do not depend on the overall dust production rate. Our results open the prospect for deducing the distribution of gas in circumstellar disks by observing their dust. We have qualitatively compared our models with two observed transitional disks around HR 4796A and HD 141569A. (Gas component has been detected, but not yet mapped in detail, in the second object.) Dust migration can result in observation of a ring or a bimodal radial dust distribution, possibly very similar to the ones produced by gap-opening planet(s) embedded in the disk, or shepherding it from inside or outside. We conclude that a convincing planet detection via dust imaging should include specific non-axisymmetric structure (spiral waves, streamers, resonant arcs) following from the dynamical simulations of perturbed disks.

The penetrating power of X-rays coupled with the high flux of 3rd generation synchrotron sources makes X-ray tomography to excel among fast imaging methods . To exploit this asset of synchrotron sources is the motivation for setting up an ultra-fast tomography endstation at the TOMCAT beamline. The state of the art instruments at synchrotron sources offer routinely a temporal resolution of tens of seconds in tomography. For a number of applications, for example biomedical studies, the relevant time scales (breathing, heartbeat) are rather in the range of 0.5-2 seconds. To overcome motion artifacts when imaging such systems a new ultra-fast tomographic data acquisition scheme is being developed at the TOMCAT beamline. We can acquire a full set of projections at sub-second timescale in monochromatic or white-beam configuration. We present a feasibility study with the ultimate aim to achieve sub-second temporal resolution in 3D without significant deterioration of the spatial resolution. For the first time, the 3D dynamics of the very early stages of a quickly aging liquid foam can be visualised with high quality and sufficiently large field of view.

Aim: We report a magneto-fluorescent theranostic nanocomplex targeted to neutrophil gelatinase-associated lipocalin (NGAL) for imaging and therapy of pancreatic cancer. Materials & methods: Gold nanoshells resonant at 810 nm were encapsulated in silica epilayers doped with iron oxide and the near-infrared (NIR) dye indocyanine green, resulting in theranostic gold nanoshells (TGNS), which were subsequently conjugated with antibodies targeting NGAL in AsPC-1-derived xenografts in nude mice. Results: Anti-NGAL-conjugated TGNS specifically targeted pancreatic cancer cells in vitro and in vivo providing contrast for both NIR fluorescence and T2-weighted MRI with higher tumor contrast than can be obtained using long-circulating, but nontargeted, PEGylated nanoparticles. The nanocomplexes also enabled highly specific cancer cell death via NIR photothermal therapy in vitro. Conclusion: TGNS with embedded NIR and magnetic resonance contrasts can be specifically targeted to pancreatic cancer ...

Staphylococcus aureus is a major human pathogen. Despite high incidence and morbidity, molecular mechanisms occurring during infection remain largely unknown. Under defined conditions, biofilm formation contributes to the severity of S. aureus related infections. Extracellular DNA (eDNA), a component of biofilm matrix released from apoptotic bacteria, is involved in biofilm structure and stability. In many bacterial biofilms, eDNA originates from cell lysis although eDNA can also be actively secreted or exported by bacterial membrane vesicles. By screening the Nebraska transposon library, we identified rpiRc as a biofilm regulator involved in eDNA regulation. RpiRc is a transcription factor from the pentose phosphate pathway (PPP) whose product is a polysaccharide intercellular adhesin (PIA) precursor. However, rpiRc mutant strain showed neither susceptibility to DispersinB® (a commercially available enzyme disrupting PIA biofilms) nor alteration of ica transcription (the operon regulating PIA production). Decreased biofilm formation was linked to Sln, an extracellular compound degrading eDNA in an autolysis independent pathway. Biofilm susceptibility to antibiotics in wt and mutant strains was tested using a similar protocol as the Calgary biofilm device. Involvement of RpiRc in S. aureus virulence was assessed ex vivo by internalization experiments into HEK293 cells and in vivo in a mouse model of subcutaneous catheter infection. While minimum inhibitory concentrations (MICs) of planktonic cells were not affected in the mutant strain, we observed increased biofilm susceptibility to almost all tested antibiotics, regardless of their mode of action. More importantly, the rpiRc mutant showed reduced virulence in both ex vivo and in vivo experiments related to decreased fnbpA-B transcription and eDNA production. RpiRc is an important regulator involved in eDNA degradation inside the matrix of mature PIA independent biofilms. These results illustrate that RpiRc contributes to increased antibiotic tolerance in mature bacterial biofilm and also to S. aureus cell adhesion and virulence during subcutaneous infection. .

One barrier to apply current tri-octylphosphine oxide (TOPO) based quantum dots (QDs) to biomedical imaging is that the TOPO on TOPO-QDs can be replaced by the proteins in living system, which may cause the degradation of QDs and/or deactivation of protein. In order to develop biocompatible optical imaging agents, a novel triblock copolymer, designed as a multidentate ligand, was synthesized to coat quantum dot nanocrystals (QDs). The copolymer consists of a polycarboxylic acid block at one end and a polythiol block at the other end with an intervening cross-linked poly(styrene-co-divinylbenzene) block bridging the ends. The multiple mercapto groups from the polythiol block act as multidentate ligands to stabilize QDs, while the polycarboxylic acid block improves the water solubility of QDs and offers reaction sites for surface modification or conjugation with bimolecules. The cross-linked poly(styrene-codivinylbenzene) block provides a densely compacted hydrophobic shell. This shell will act as a barrier to inhibit the degradation of QDs by preventing the diffusion of ions and small molecules into the core of QDs. This new multidentate polymer coating facilitates the transfer of QDs from organic solvent into aqueous phase. The QDs directly bound to multidentate mercapto groups instead of TOPO are less likely to be affected by the mercapto or disulfide groups within proteins or other biomolecules. Therefore, this research will provide an alternative coating material instead of TOPO to produce QDs which could be more suitable for in vivo use under complex physiological conditions.

The recognition of the biological, diagnostic and medical importance of exosomes has given rise to an urgent need for efficient labelling of these extracellular vesicles in ways that do not alter their inherent characteristics. We report for the first time an endogenous method to NIR-fluorescent labelled exosomes using an amphiphilic probe without the need for immunolabelling or synthetic or chromatographic manipulation of exosomes. Comparative analyses of labelled and unlabelled exosomes with NTA, AFM, flow cytometry and immunoblot analysis all show a high degree of similarity. Spectroscopic analysis and fluorescence imaging confirmed the ability to visualise purified NIR-exosomes.

The cysteine cathepsins are a group of 11 proteases whose function was originally believed to be the degradation of endocytosed material with a high degree of redundancy. However, it has become clear that these enzymes are also important regulators of both health and disease. Thus, selective tools that can discriminate between members of this highly related class of enzymes will be critical to further delineate the unique biological functions of individual cathepsins. Here we present the design and synthesis of a near-infrared quenched activity-based probe (qABP) that selectively targets cathepsin S which is highly expressed in immune cells. Importantly, this high degree of selectivity is retained both in vitro and in vivo. In combination with a new green-fluorescent pan-reactive cysteine cathepsin qABP we performed dual color labeling studies in bone marrow derived immune cells and identified vesicles containing exclusively cathepsin S activity. This observation demonstrates the va...

Ce travail présente la synthèse et l’étude d’une nouvelle famille de composés photochromes de type di(hétéroaryl)éthène ainsi que leur utilisation comme ligand pontant en chimie de coordination dans le but d’élaborer des matériaux moléculaires à propriétés photomodulables. Depuis ces dernières années, le photochromisme occupe une place prépondérante dans le développement de nouveaux matériaux photosensible.Ainsi, de nouveaux di(hétéroaryl)éthènes, dérivés de terarylènes, ont été synthétisés et leurs propriétés photochromes ont été étudiées en détail. Ces nouveaux systèmes, baptisés tétrarylènes, ont également permis l’obtention de composés dissymétriques présentant un biphotochromisme exclusif. Enfin, ces tétrarylènes ont pu être utilisés pour la synthèse de complexes mono- et di-nucléaires de Cu(II). Certains cas ont alors révélé l’éjection réversible du métal de la cavité chélatante par étude RPE.Mots clés : photochromisme, diaryléthènes, terarylènes, commutation, Absorption trans...

There is growing evidence that functional brain images in alert task-engaged subjects contain taskrelated but stimulus-independent signals in addition to stimulus-evoked responses. It is important to separate these different components when analyzing the neuroimaging signal. Using intrinsicsignal optical imaging combined with electrophysiology we had earlier reported a particular 'trialrelated signal' in the primary visual cortex (V1) of alert monkeys performing periodic fixation tasks. This signal periodically modulated V1 tissue blood volume, in time with anticipated trial onsets. Unlike visually evoked blood volume changes, however, this signal was present even in total darkness. Further, it could not be predicted by concurrently recorded spiking or local field potentials. Here we use our earlier recording techniques to analyze the spatial distribution of this trial-related signal over our imaged area (10 mm square, subdivided into a 16 × 16 grid, i.e. at 625 micron resolution). We show that the signal is spatially coherent and essentially homogeneous over the imaged region and fails to be predicted by concurrent electrode recordings even at the resolution of a single grid square at the electrode tip. As a corollary we show that the signal is critically linked to the animals' engagement in a task. Not only does the trial-related signal entrain accurately and precisely to any task timing at which the animal was willing to perform; the signal also loses the entrained trial-locked pattern dramatically, within a single trial, when the animal stops performing correctly. Thus the signal is very unlikely to be an ongoing task-independent vascular oscillation. These findings will help categorize the likely distinct varieties of nonstimulus-related signals evoked during behavioral tasks, and lead to a further understanding of the elements comprising the net neuroimaging response.

Summary OBJECTIVES : The aim of this study was to characterize facial and jaw morphology of children with Class III malocclusion in early mixed dentition. This study was conducted on 7- to 8-year-old Caucasian children, 48 children with Class III malocclusion and 91 children with normal occlusion. Surface images of faces and study casts were obtained using laser scanning. Two average facial templates were constructed for the males and females in the control group. The facial images were superimposed on the corresponding average templates. Facial parameters, palatal volumes, and gingival surface areas were measured and group differences were quantified. The analysis of variance was used for statistical evaluation of the measured parameters. The results revealed shorter lower face height (P &lt; 0.001), concave facial profile (P &lt; 0.001), retruded maxilla (P &lt; 0.001), protruded mandible (P &lt; 0.001), retrusive mid-face restricted area (P &lt; 0.001), reduced gingival surface a...

Imaging techniques have evolved impressively lately, allowing whole new concepts like multimodal imaging, personal medicine, theranostic therapies, and molecular imaging to increase general awareness of possiblities of imaging to medicine field. Here, we have collected the selected (3D) imaging modalities and evaluated the recent findings on preclinical and clinical inflammation imaging. The focus has been on the feasibility of imaging to aid in inflammation precision medicine, and the key challenges and opportunities of the imaging modalities are presented. Some examples of the current usage in clinics/close to clinics have been brought out as an example. This review evaluates the future prospects of the imaging technologies for clinical applications in precision medicine from the pre-clinical development point of view.

We describe an approach to terrestrial remote sensing using a novel technique, imaging interferometry. A practical implementation of the instrument, the Digital Array Scanned Interferometer (DASI), has been under development at our laboratories. An overview of recent terrestrial scenes measured using an airborne DASI sensor is presented.

Author(s): Gosla, Amin; Hoang, Preston; Robles, Marco; Ganesh, Priyanka; Dhariwal, Guriqbal | Abstract: Background: Cancer as a disease has defined our current era. In the United States alone, two out of every five people will develop cancer at some point in their lives. Chemotherapy, although powerful, does not always reduce tumor size. For these patients, called non-responders, it can take up to 18 weeks to change their course of action because chemotherapy is currently monitored through palpation, or feeling for tissue stiffness. The result is wasted money on the initial drugs, precious time lost, and a plethora of side effects.Our device, Oncospect, is a tool for oncologist to quantitatively track the progress of chemotherapy on a metabolic level. Benefits include lower costs, less side-effects, and better patient outlook. Our aim is to empower oncologists to make personalized treatment plans for patients.Faculty Adviser: Prof. Bruce Tromberg, Surgery - Beckman Laser Institute b...

AlSat-1, the First Algerian National Satellite, and the first of five microsatellites in the Disaster Monitoring Constellation (DMC), was launched on the 28 November 2002 from Plesetsk. AlSat-1 was joined by SSTL built Microsatellites for Nigeria, the United Kingdom and Turkey with the second DMC launch on the 23 September 2003 and the fifth microsatellite for China was launched into the same orbit by the third DMC launch on the 27 October 2005. A team of eleven (11) Algerian engineers has been trained at Surrey through the AlSat-1 project with specializations in the following disciplines: System Engineering, ADCS, Power, RF, OBDH, Mechanical and Launch Interface, Earth Observation Payload, GPS, Operation, TTC and Propulsion. AlSat-1, the first space asset to the country provides indigenous national space capability, unique independent earth observation source and international cooperation opportunities. In a constellation with four other satellites, Algeria will have daily access t...

Radiochromic plastic and gel materials have recently emerged which can yield 3D dose information over clinical volumes in high resolution. These dosimeters can provide a much more comprehensive verification of complex radiation therapy treatments than can be achieved by conventional planar and point dosimeters. To achieve full clinical potential, these dosimeters require a fast and accurate read-out technology. Broad-beam optical-computed tomography (optical-CT) systems have shown promise, but can be sensitive to stray light artifacts originating in the imaging chain. In this work we present and evaluate a method to correct for stray light artifacts by deconvolving a measured, spatially invariant, point spread function (PSF). The correction was developed for the DLOS (Duke large field-of-view optical-CT scanner) in conjunction with radiochromic PRESAGE ® dosimeters. The PSF was constructed from a series of acquisitions of projection images of various sized apertures placed in the optical imaging chain. Images were acquired with a range of exposure times, and for a range of aperture sizes (0.2-11 mm). The PSF is investigated under a variety of conditions, and found to be robust and spatially invariant, key factors enabling the viability of the deconvolution approach. The spatial invariance and robustness of the PSF are facilitated by telecentric imaging, which produces a collimated light beam and removes stray light originating upstream of the imaging lens. The telecentric capability of the DLOS therefore represents a significant advantage, both in keeping stray light levels to a minimum and enabling viability of an accurate PSF deconvolution method to correct for the residual. The performance of the correction method was evaluated on projection images containing known optical-density variations, and also on known 3D dose distributions. The method is shown to accurately account for stray light on small field dosimetry with corrections up to 3% in magnitude shown here although corrections of >10% have been observed in extreme cases. The dominant source of stray light was found to be within the imaging lens. Correcting for stray light extended the dynamic range of the system from ~30 to ~60 dB. The correction should be used when measurements need to be accurate within 3%.

Labeling and visualizing cells and sub-cellular structures within thick tissues, whole organs and even intact animals is key to studying biological processes. This is particularly true for studies of neural circuits where neurons form sub-micron synapses but have arbors that may span millimeters in length. Traditionally labeling is achieved by immunofluorescence; however diffusion of antibody molecules (&gt;100 kDa) is slow and often results in uneven labeling with very poor penetration into the centre of thick specimens; these limitations can be partially addressed by extending staining protocols to over a week (Drosophila brain) and months (mice). Recently we developed an alternative approach using genetically encoded chemical tags CLIP, SNAP, Halo and TMP for tissue labeling; this resulted in &gt;100 fold increase in labeling speed in both mice and Drosophila, at the expense of a considerable drop in absolute sensitivity when compared to optimized immunofluorescence staining. We ...

Many optical measurements that are subject to high levels of background illumination rely on phase sensitive lock-in detection to extract the useful signal. If modulation is applied to the portion of the signal that contains information, lockin detection can perform very narrowband (and hence low noise) detection at frequencies well away from noise sources such as 1/f and instrumental drift. Lock-in detection is therefore used in many optical imaging and measurement techniques, including optical coherence tomography, heterodyne interferometry, optoacoustic tomography and a range of pump-probe techniques. Phase sensitive imaging is generally performed sequentially with a single photodetector and a lock-in amplifier. However, this approach severely limits the rate of multi-dimensional image acquisition. We present a novel linear array chip that can perform phase sensitive, shot-noise limited optical detection in up to 256 parallel channels. This has been achieved by employing four independent wells in each pixel, and massively enhancing the intrinsic well depth to suppress the effect of optical shot noise. Thus the array can reduce the number of dimensions that need to be sequentially scanned and greatly speed up acquisition. Results demonstrating spatial and spectral parallelism in pump-probe experiments are presented where the a.c. amplitude to background ratio approaches 1 part in one million.

Spreading depolarization (SD) generates significant alterations in cerebral haemodynamics, which can have detrimental consequences on brain function and integrity. Ketamine has shown an important capacity to modulate SD; however, its impact on SD haemodynamic response is incompletely understood. We investigated the effect of two therapeutic ketamine dosages, a low-dose of 2 mg/kg/h and a high-dose of 4 mg/kg/h, on the haemodynamic response to SD in the gyrencephalic swine brain. Cerebral blood volume, pial arterial diameter and cerebral blood flow were assessed through intrinsic optical signal imaging and laser-Doppler flowmetry. Our findings indicate that frequent SDs caused a persistent increase in the baseline pial arterial diameter, which can lead to a diminished capacity to further dilate. Ketamine infused at a low-dose reduced the hyperemic/vasodilative response to SD; however, it did not alter the subsequent oligemic/vasoconstrictive response. This low-dose did not prevent the baseline diameter increase and the diminished dilative capacity. Only infusion of ketamine at a high-dose suppressed SD and the coupled haemodynamic response. Therefore, the haemodynamic response to SD can be modulated by continuous infusion of ketamine. However, its use in pathological models needs to be explored to corroborate its possible clinical benefit.

Haemodynamic responses to spreading depolarizations (SDs) have an important role during the development of secondary brain damage. Characterization of the haemodynamic responses in larger brains, however, is difficult due to movement artefacts. Intrinsic optical signal (IOS) imaging, laser speckle flowmetry (LSF) and electrocorticography were performed in different configurations in three groups of in total 18 swine. SDs were elicited by topical application of KCl or occurred spontaneously after middle cerebral artery occlusion. Movement artefacts in IOS were compensated by an elastic registration algorithm during post-processing. Using movement-compensated IOS, we were able to differentiate between four components of optical changes, corresponding closely with haemodynamic variations measured by LSF. Compared with ECoG and LSF, our setup provides higher spatial and temporal resolution, as well as a better signal-to-noise ratio. Using IOS alone, we could identify the different zones...

The aim was to characterize the effects of magnesium sulfate, using i.v. bolus and local administration, using intrinsic signal imaging, and on electrocorticographic activity during the induction and propagation of spreading depolarizations in the gyrencephalic porcine brain. Local application of magnesium sulfate led to a complete inhibition of spreading depolarizations. One hour after washing out the topical magnesium sulfate, re-incidence of the spreading depolarizations was observed in 50% of the hemispheres. Those spreading depolarizations showed attenuation in hemodynamic characteristics and speed in intrinsic optical signal imaging. The electrical amplitude decreased through electrocorticographic activity. Intravenous magnesium therapy showed no significant effects on spreading depolarization incidence and characteristics.

The design, laboratory calibrations, and flight tests of a new optical imaging instrument, the two-dimensional stereo (2D-S) probe, are presented. Two orthogonal laser beams cross in the middle of the sample volume. Custom, high-speed, 128-photodiode linear arrays and electronics produce shadowgraph images with true 10-μm pixel resolution at aircraft speeds up to 250 m s−1. An overlap region is defined by the two laser beams, improving the sample volume boundaries and sizing of small (&lt;∼100 μm) particles, compared to conventional optical array probes. The stereo views of particles in the overlap region can also improve determination of three-dimensional properties of some particles. Data collected by three research aircraft are examined and discussed. The 2D-S sees fine details of ice crystals and small water drops coexisting in mixed-phase cloud. Measurements in warm cumuli collected by the NCAR C-130 during the Rain in Cumulus over the Ocean (RICO) project provide a test bed to...

With the development of Synthetic Aperture Radar (SAR) in terms of multi-band, multi-polarization and high-resolution data, space radar remote sensing for archaeology has become a potential field for research. Nevertheless, the archaeological detection capability of this technology has so far not been fully assessed. This paper is a pioneering effort to assess the potential of satellite SAR X-band data in the detection of archaeological marks. We focus on the results obtained from a collaborative contribution jointly carried out by archaeologists and remote sensing experts in order to test the use of COSMO-SkyMed data in different contexts and environmental conditions. The methodological approaches we adopted are based on two different feature-enhancement procedures: (i) multi-temporal

Aims. We characterise the underlying stellar host in a sample of 20 blue compact galaxies (BCGs), by fitting their two-dimensional light distributions. Their derived host structural parameters and those of eight other BCGs already obtained in a previous paper are related to galaxy properties, such as colours and gas content. These properties are also compared with those of other galaxy types. Methods. The structural parameters of the host were derived by fitting a two-dimensional PSF-convolved Sérsic model to deep optical images in several bandpasses (B, V, R, I). We followed a fitting technique that consists in the accurate masking-out of the star-forming regions in several steps. Results. All the BCG hosts but one show low Sérsic indexes (0.5 < ∼ n < ∼ 2), with mean effective radius r e,B = 1.11 ± 0.74 kpc and mean surface brightness μ e,B = 22.59 ± 0.68 mag arcsec -2 . Host effective radii scale linearly with their luminosity, while n and μ e do not. In addition, host colours and structural parameters are not linearly correlated. Overall, the flux enhancement caused by the starburst is about 0.8 mag, while their B -R colours decrease by about 0.2 mag. Galaxies with more luminous and extended hosts show larger and luminous starburst components, whereas the relative strength of the burst (L burst /L host ) does not show any significant dependence on the host luminosity (or mass). While hosts show B -R = 0.95 ± 0.26 in median, galaxies with redder hosts ( B -R = 1.29 ± 0.10) and with bluer hosts ( B -R = 0.66 ± 0.10) are distinguished among the more and less luminous systems, respectively. Overall, BCG hosts are more compact (by a factor ∼2) and have higher central surface brightnesses (by about ∼2 mag) than dIs and most dEs. BCG hosts and isolated dIs are indistinguishable in the B-band Tully-Fisher relation (TFR). We found that about 50-60% of the galaxies are more underluminous than those late-type discs with the same circular velocity. This feature is more important when luminosities are converted into stellar masses, while it tends to diminish when the Hi gas mass is added. Deviations among host masses for a given circular velocity from the stellar TFR correlate with their Hi mass-to-luminosity ratio (M HI /L B ), whereas deviations from the gas+stellar TFR do not. Overall, our findings suggest that the baryonic mass in BCGs tends to normal values, but BCGs tend to be inefficient by producing stars, especially toward the low-mass, gas-rich, and bluest hosts, in a similar way to dIs.

A nanocrystalline thin films of PbS with both thickness (400 and 600)nm have been prepared successfully by chemical bath deposition technique on glass and Si substrates. The structure and morphology of these films were studied by X-ray diffraction and atomic force microscope. It shows that the structure is polycrystalline and the average crystallite size has been measured. The optical parameters of the prepared films as absorption, transmittance, reflectance , optical energy gap, and absorption coefficient were found as affected by varying the thickness. The optical measurement showed that (PbS) films have an allowed direct energy gap (Eg) and that decreases with thickness increasing. The photoconductive measurement gives the positive photoconductive for PbS thin films.

Magnetic resonance imaging (MRI) has been successfully applied to many of the applications of molecular imaging. This review discusses by example some of the advances in areas such as multimodality MR-optical agents, receptor imaging, apoptosis imaging, angiogenesis imaging, noninvasive cell tracking, and imaging of MR marker genes.

Optical coherence tomography (OCT) is a non-invasive depth resolved optical imaging modality, that enables high resolution, cross-sectional imaging in biological tissues and materials at clinically relevant depths. Though OCT offers high resolution imaging, the best ultra-high-resolution OCT systems are limited to imaging structural changes with a resolution of one micron on a single B-scan within very limited depth. Nanosensitive OCT (nsOCT) is a recently developed technique that is capable of providing enhanced sensitivity of OCT to structural changes. Improving the sensitivity of OCT to detect structural changes at the nanoscale level, to a depth typical for conventional OCT, could potentially improve the diagnostic capability of OCT in medical applications. In this paper, we demonstrate the capability of nsOCT to detect structural changes deep in the rat cornea following superficial corneal injury.

Fluorescent cross-linked nanoparticles with variable fluorophore loading amounts, locations, and particle sizes were synthesized from sequential one-pot functionalization/cross-linking of block copolymer micelles with amine-terminated dye and cross-linker molecules, via reductive amination and amidation. The fluorescence quantum yield and brightness of these nanoparticles were evaluated by steady-state and dynamic fluorescence methods. The results demonstrate that the quantum yield and brightness of the fluorescent nanoparticles correlated directly with the number of dyes/nanoparticle and the nanoparticle size. A strategy to increase the fluorescence brightness of nanoparticles with fluorescein and near-infrared dyes is proposed.