Quasielastic light scattering (QLS) and laser diffractometry (LD) are relatively novel nondestructive procedures for estimating the sizes of bacterial spores in suspension. This study for the first time directly compared the two with a destructive procedure, namely, scanning electron microscopy (SEM), for quasispherical spores of Bacillus sphaericus. Because of the ...

Modern neuroimaging techniques use signals originating from microcirculation to map brain function. In this study, activity-dependent changes in oxyhemoglobin, deoxyhemoglobin, and light scattering were characterized by an imaging spectroscopy approach that offers high spatial, temporal, and spectral resolution. Sensory stimulation of cortical columns initiates tissue hypoxia and vascular responses that ...

The light-scatter characteristics of lymphocytes are commonly used to gate lymphocytes for further analysis in a lysed whole-blood assay. Because lymphocytes can be identified by antigens that they possess, a light-scatter gate can be validated by measuring parameters other than light scatter. When a specimen possesses poor light scatter (usually ...

The backscattering enhancement of light from random media is analyzed for situations in which the scatterers are illuminated with spatially partially coherent light. The effect of coherence is incorporated into the existing theories by use of the angular correlation description for the illuminating light field. When the area of illumination ...

Using a bifurcated lightguide placed on the surface of a prism of the electric organ slice of Torpedo, the generation of postsynaptic potentials by direct stimulation was found to be associated with readily detectable, disphasic optical changes. The changes consisted of a decrease in light-scattering during the rising phase of ...

Various residual visual capacities have been reported for the phenomenally blind field of hemispherectomized patients, providing evidence for the relative roles of cortical and subcortical pathways in vision. We attempted to characterize these functions by examining the ability of five patients to detect, localize, and discriminate high-contrast flashed, flickering and ...

PURPOSE: Epidemiologic studies have shown that the onset of cortical cataract occurs primarily in the inferonasal human lens and that the incidence of cortical cataract is correlated with ultraviolet light. Ray tracing analysis has suggested that the peripheral cornea concentrates light on the opposite peripheral lens and that the nose ...

PURPOSE: To compare corneal light scattering after laser in situ keratomileusis and photorefractive keratectomy in rabbit eyes. METHODS: For laser in situ keratomileusis, a 5-mm, -10-diopter spherorefractive resection was performed on the stromal bed under a corneal flap. Corneal light scattering was objectively measured for 12 weeks, and compared to ...

Light transmittance (T) in the CA1 region of hippocampal slices was measured during exposure to media of various osmolarities to determine the utility of optical measurements as an index of changes in cell volume. In slices positioned at the gas-liquid interface, hypo-osmotic medium consistently produced a decrease in T and ...

Full and depolarized static light-scattering (LS) experiments have been carried out to characterize the size and shape of colloidal suspensions. Results have been compared with theoretical predictions following the extended-boundary-condition method (T-matrix) formalism for scattering by nonspherical particles. Theory-to-experiment data fitting has yielded size-shape data that compare well with electron-microscopy ...

Light scattering experiments are usually performed at wavelengths away from absorption bands, but for species that aggregate, enhancements in light scattering of several orders of magnitude can be observed at wavelengths characteristic of these species. Resonance light scattering is shown to be a sensitive and selective method for studying electronically ...

The methods currently utilized in dentistry to detect caries lesions have their limitations and alternatives are being investigated. A promising option is tooth transillumination which is based on an increase of light scattering or light absorption in the affected tissue region. In this study transillumination applied to detect approximal caries ...

A detailed radiative transfer calculation has been carried out to estimate the effects of rotational Raman scattering (RRS) on satellite measurements of backscattered ultraviolet radiation. Raman-scattered light is shifted in frequency from the incident light, which causes filling in of solar Fraunhofer lines in the observed backscattered spectrum (also known ...

Recent anatomic work has shown that the capillary network of the fovea is multilaminar. We have identified the elements of this network that are visualized by fluorescein angiography and those that are missed. Fluorescein angiograms of monkey retinas (Macaca fascicularis) with good visualization of individual capillaries were obtained by standard ...

PURPOSE: The authors sought to discover whether there are differences in the degree of spatial order in the fibrillar ultrastructure between anterior and posterior stroma. METHODS: Human corneas were obtained from eye bank eyes. Although they had been classified as normal, some swelling remained after 3 hours of deturgescence. Freshly ...

Using a new technique based on the fanning of a coherent light beam in a photorefractive BaTiO(3) crystal, we have measured the angular distribution of forward light scattering by quartz fibers of radii from 15 to 30 µm. Data have been obtained over the angular range 0° to 0.3° and ...

Static light scattering is widely used for sizing of particles with radii in the range of 50 nm up to several micrometers. These experiments usually require very low particle concentrations (<10(-4)) for prevention of multiple scattering. As a consequence, nonabsorbing samples that are suited for light-scattering investigations must be transparent ...

We have discovered that the sulfonation of polystyrene can form a gradient-index medium useful for lightfocusing purposes. We found that the refractive index of sulfonated polystyrene varies with the degree of sulfonation and that the refractive index of the fully sulfonated polystyrene decreased by approximately 0.06 at 0.633 microm from ...

The most widely used technique for dynamic estimates of sarcomere length in muscle is laser light diffraction. We have identified conditions under which artifactual oscillations can arise in apparent sarcomere length measured by this technique and report methods to reduce the effect. Altringham et al. (1984) first reported that the ...

Angular dependencies of the scattered light intensity were measured on Si wafers that have different crystallographic orientations by using a He-Ne laser (λ = 632.8 nm, 80 µm spot diameter). During the experiment the Si wafer was fixed relative to the incident beam. Regular patterns were found in the azimuthal-angle-resolved ...

A newly-developed fibre-optic sensor (wavelength of 670 nm) was used to measure the index gradient in 16 human lenses ranging in age from 38 to 78 years. Two of these lenses had nuclear cataract. The refractive index, calculated from the proportion of reflected light at the sensor/sample interface, appeared to ...

PURPOSE: The influence of cataract on the blue-on-yellow visual field is unknown. The aim of the study was to compare the effect of age-related cataract on the normal blue-on-yellow (B-Y), yellow-on-yellow (Y-Y) and white-on-white (W-W) visual field. METHODS: Forty normal subjects (age range, 60 to 81 years) randomly performed B-Y, ...

The development of noninvasive optical studies necessitates an understanding of the biological parameters which affect light propagation in soft tissues. In the present report, we have measured the optical properties of various normal (i.e., perfused liver, brain, skeletal muscle, white adipose tissue) and neoplastic rodent tissues (i.e., glioma, hepatoma, mammary ...

A method for time-resolved recording of light scattering in thin, highly scattering media is described. Subpicosecond pulses from a high-power Ti:sapphire laser are used, and single-shot recordings of the scattered light are made with a fast streak camera. The method is applied to the study of light scattering in paper, ...

BACKGROUND: Although it is known that backward light scatter increases transiently following most excimer laser photorefractive keratectomies (PRKs), it is not clear that there is a significant increase in forward light scatter, which is of primary concern for the patient. The object of this study was to determine if there ...

Time resolved measurements of the nuclear volume response of human peripheral Tlymphocytes, under aniosmotic conditions, are presented. In the experiments slit scanning flowcytometry methods were used. We propose an extension to the standard solid viscoelastic model to interpret the observed dynamical behaviour of the nucleus. It is shown that experimental ...

Light scattering for normal and cataractous lenses from 21-86 yr old donors was measured in vitro. As expected, scattering increased with severity of cataract. Scattering decreased with angle according to a power law. This corresponded to the power law finding for functional straylight measurements in early-cataract patients using white light ...

A comparison is presented of the effects of particle size, concentration, and detector depth on side scattering for linearly and circularly polarized incident light. The scattering medium consists of various concentrations of particles, which are either 1.24, 0.494, 0.36, 0.123, or 0.065 µm in diameter, and which were mixed into ...

Tooth color is determined by the paths of light inside the tooth and absorption along these paths. This paper tests the hypothesis that, since the paths are determined by scattering, a relation between color and scattering coefficients exists. One hundred and two extracted incisors were fixed in formalin, mounted in ...

In order to understand the correlation between nuclear opacity and spectral light transmission factor, the in vivo light scattering intensity of Scheimpflug lens images and the light transmission through slices of surgically removed nucleus were examined densitometrically as well as spectrophotometrically respectively, using both human and Brown Norway rat lenses. ...

Techniques based on transillumination of teeth with visible light will be a valuable aid in caries diagnosis, if a higher sensitivity than that of the present Foti method is achieved. Therefore, a better understanding of light propagation through teeth is required, and hence it is useful to investigate the propagation ...

<p>We show that the angular distribution of scattered light (haze) from tilted-columnar birefringent thin films is highly anisotropic. When a narrow laser beam is incident normally upon a substrate coated with a tilted-columnar film, such as titania deposited at 60° to a thickness of ≈2 µm, the distribution of light ...

BACKGROUND AND OBJECTIVE: Excimer laser-corneal tissue interaction liberates highly reactive free radicals. Our aim was to determine if intraoperative application of antioxidants reduces the postoperative corneal light scattering by minimizing free radical-mediated cellular injury. STUDY DESIGN/MATERIALS AND METHODS: Phototherapeutic keratectomy (PTK) was performed in 20 rabbit eyes. Following 40-microns epithelial ...

The singlet oxygen quantum yield (phi delta) for Photofrin solubilized by Triton X-100 was measured in homogeneous and light-scattering media using the photosensitized inactivation of lysozyme as an internal actinometer. Higher values of phi delta at 630 nm than at 514 nm are attributed to the formation of a far-red-absorbing ...

Equilibrium unfolding experiments of the E. coli chaperonin GroEL were performed in guanidine hydrochloride. A reversible unfolding intermediate was observed in very low concentrations of denaturant (< 0.5 M guanidine hydrochloride). This intermediate was characterized by a decreased light scattering intensity and an increased binding of the fluorescent probe 1-anilino-8-naphthalene ...

Angular induction is the process by which one line segment can bias judgment of orientation and/or collinearity of another segment, and it has been established that the magnitude of error is a determinate function of the relative angle between the two. We examined how these known relationships are affected by ...

The distribution of the scattering coefficient (as defined in the appendix) at a wavelength of 647.1 nm along the visual axis of human eye lenses was investigated using a specially designed set-up for spatially resolved measurements of the intensity of the scattered light. For the same lenses, the distribution of ...

A method has been developed to study erythrocyte aggregation parameters based on He-Ne laser light scattering. Laser light is passed through a well mixed sample of blood and the forward scattered light intensity is recorded continuously. The orientation of erythrocytes, formation of aggregates and their sedimentation under the gravitational field ...

A method for correcting integrating-sphere signals that considers differences in the angular distribution of scattered light is extended to sources of errors that are due to stray light from imperfect optical components. We show that it is possible to measure low levels of scattering, below 1%, by using a standard ...

The absorption and scattering coefficient of a macroscopically homogeneous strongly scattering medium (lipid emulsion) containing Methylene Blue is quantitatively measured in the spectral range from 620 to 700 nm. We conduct the measurements in the frequency domain by using a light-emitting diode (LED) whose intensity is modulated at a frequency ...

An analytical model of the scattering structure factor for an assembly of noninteracting hard disks has recently appeared in the literature [Phys. Rev. A 42, 5978-5989 (1990)]. We employ this model to calculate correlated light scattering by monodispersions and binary mixtures of condensation droplets on a window pane. We find ...

Oblate drops of water illuminated perpendicular to their symmetry axis exhibit catastrophe patterns near the primary-rainbow scattering angle. Previous patterns include the hyperbolic umbilic focal section and separate lips events [see, e.g., H. J. Simpson and P. L. Marston, Appl. Opt. 30, 3468 (1991)]. The present observations concern a much ...

Light scattering in the eye is reviewed, and its influence on vision is discussed in some detail. Isotropic scattering and formation of halos around point sources are described with reference to theory and experiments. Artists usually take intraocularly scattered light into account when painting natural scenes. A method to achieve ...

Here we report the first observation of hyper-Rayleigh light scattering from bacteriorhodopsin in the form of an aqueous suspension of unoriented purple membranes. A typical purple membrane suspension used in our experiments contains approximately 10(8) randomly oriented purple membranes. Each purple membrane contains approximately 10(5) bacteriorhodopsin molecules in a two-dimensional ...

One of the many calibrations performed for a scientific-quality spectrometer is the characterization of its scattered-light properties. The scattered light can arise from any optical surface, and light leaks or scattering from baffles can also contribute to the instrumental stray-light level. For a diffraction-grating spectrometer the primary contribution to instrumental ...

Flow cytometric measurements of light scattering of polystyrene calibration beads revealed remarkable Lissajous-like loops in two-parameter scatter plots. The existence of such loops is shown to be in qualitative agreement with Lorenz-Mie scattering theory of homogeneous spheres. The occurrence of these patterns reflects the extreme particle size dependency of perpendicular ...

We have observed cones of diffracted light by illuminating a crystal of bismuth silicate with a single beam of light while applying an electric field across the crystal. The scatter rings are a result of the preferential amplification of noise, which we explain here using the Ewald sphere construction.

The study investigated the effects of induced forward light scatter on the normal blue-on-yellow perimetric profile. Light scatter was induced using 0.00%, 0.08% and 0.16% suspensions of 500-nm-diameter polystyrene microspheres contained in optical cells. White-on-white, yellow-on-yellow and blue-on-yellow perimetry was performed using a modified Humphrey Field Analyser 640. Fifteen subjects ...

The scattering of light from cutting tools is studied. The contribution of cutting tool edge parameters (height and width) to scattering patterns and the influence of side surface roughness on scattering patterns are investigated. An angle-limited integrated scattering method is developed and analyzed for fast determination of edge parameters.

Measurements of the light scattered by a sample contain information regarding the physical properties of the sample. Laser light-scattering measurements can be made unobtrusively in environments that are inaccessible to other types of measurements, so laser light-scattering techniques have become an important tool in aerosol research. The primary difficulty associated ...