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At least 973 records · Page 54Linked to original sources
PubMed1997

[Riboflavin Reference Standard (Control 951) of National Institute of Health Sciences].

The raw material for riboflavin was tested for preparation of the "Riboflavin Reference Standard (Control 951)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 284.6 degrees C (decomposition): specific absorbance, E1cm1% = 857 (267 nm), 277 (373 nm), 326 (445 nm); IR spectrum, the same as that of JP Riboflavin Reference Standard (Control 921); optical rotation, [alpha]20D = -135.6 degrees; thin-layer chromatography, three impurities were detected; high-performance liquid chromatography, a small amount of 10 impurities were detected: loss on drying, 0.10%; assay, 100.4% by spectrophotometry. Based on the above results, the raw material was authorized as the Riboflavin Reference Standard (Control 951) of National Institute of Health Sciences (Japanese Pharmacopoeia).

Japan↗
PubMed1997

[Estradiol Reference Standard (Control 961) of National Institute of Health Sciences].

The raw material for estradiol was examined for preparation of the "Estradiol Reference Standard (Control 961)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 179.1 degrees C; UV spectrum, lambda max = 281 nm; IR spectrum, the same as that of the Estradiol Reference Standard of National Institute of Health Sciences (Control 931); optical rotation, [alpha]20D = +79.5 degrees; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography (HPLC), a trace amount of three impurities were detected; loss on drying, 3.17%; assay, 99.4% by UV spectrophotometry and 99.0% by HPLC. Based on the above results, the raw material was authorized as the Estradiol Reference Standard (Control 961) of National Institute of Health Sciences.

Estradiol↗
PubMed1997

[Chlormadinone Acetate Reference Standard (Control 961) of National Institute of Health Sciences].

The raw material for chlormadinone acetate was tested for preparation of the "Chlormadinone Acetate Reference Standard (Control 961)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 215. 3 degrees C; UV spectrum, lambda max = 283.5 nm; IR spectrum, the same as that of JP Chlormadinone Acetate Reference Standard (Control 885); optical rotation, [alpha]20D = -13.0 degrees; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography, two impurities were detected; loss on drying, 0.01%; assay, 99.4% by spectrophotometry and 99.5% by HPLC. Based on the above results, the raw material was authorized as the Chlormadinone Acetate Reference Standard (Control 961) of National Institute of Health Sciences (Japanese Pharmacopoeia).

Chlormadinone Acetate↗
PubMed1976

Characterization of a red pigment-antibiotic produced by Streptomyces sp. strain NRC-C7.

The streptomycete strain NRC-C 7 isolated from some Egyptian soil samples, produces a red-coloured pH indicator antibiotic active against gram positive bacteria. The producing organism belongs to the grey series of the genus Streptomyces and has grey coloured aerial mycelium with violet pigmented substrate mycelium, the violet pigment does not diffuse into the agar medium. Glucose sodium nitrate medium proved the most suitable medium for the production of this antibiotic. The pigment was extracted from the broth and purified. The solubility, Rf values, minimal inhibiting concentrations, optical rotation, UV, and IR spectra were studied. Melting point 180, elemental analysis: carbon 51.71%, hydrogen 6.25%, and oxygen 42.04%.

Anti-Bacterial Agents↗
PubMed2001

Interstitial photodynamic therapy with rotating and reciprocating optical fibers.

BACKGROUND: Photodynamic therapy (PDT) is an effective treatment modality that allows selective destruction of malignant tumor cells. However, because of the difficulty in exposing deeper areas of tumors, the modality has strictly limited indications. In this study, the authors introduce a new method for delivering laser light to a three-dimensional, wide area with the purpose of improving the therapeutic value of PDT. METHODS: Three patients with squamous cell carcinoma of the tongue were treated with the present course. After administering porfimer sodium, laser-proof tubes were inserted through the tumor, and optical fibers were passed through the tubes. Pulse laser was emitted from the obliquely prepared fiber tip and distributed toward the target area while rotating and reciprocating the optical fiber. RESULTS: Two patients achieved a complete response without any complications or functional disabilities. The third patient, however, had a partial response and required surgery. CONCLUSIONS: The results indicate the capability of distributing laser light to an entire area of solid tumor. However, the ideal dose of laser light for the treatment of tumors remains unknown. Interstitial PDT will be more efficacious and reliable after the dosimetry is established.

Aged↗
PubMed1992

Translational head movements of pigeons in response to a rotating pattern: characteristics and tool to analyse mechanisms underlying detection of rotational and translational optical flow.

Pigeons freely standing in the centre of a two-dimensionally textured cylinder not only rotate but also laterally translate their head in response to the pattern sinusoidally oscillating or unidirectionally rotating around their vertical axis. The translational head movement dominates the response at high oscillation frequencies, whereas in a unidirectionally rotating drum head translation declines at about the same rate as the rotational response increases. It is suggested that this is a consequence of charging the 'velocity storage' in the vestibulo-ocular system. Similar to the rotational head movement (opto-collic reflex), the translational head movement is elicited via a wide-field motion sensitive system. The underlying mechanism can be described as vector integration of movement vectors tangential to the pattern rotation. Stimulation of the frontal visual field elicits largest translational responses while rotational responses can be elicited equally well from any azimuthal position of a moving pattern. Experiments where most of the pattern is occluded by a screen and the pigeon is allowed to view the stimulus through one or two windows demonstrate a short-range inhibition and long-range excitation between movement detectors that feed into the rotational system. Furthermore, the results obtained from such types of experiments suggest that the rotational system inhibits the translational system. These mechanisms may help the pigeon to decompose image flow into its translational and rotational components. Because of their translational response to a rotational stimulus, it is concluded, however, that pigeons either generally cannot perfectly perform the task or they need further visual information, like differential image motion, that was not available to them in the paradigms.

Animals↗
PubMed2006

Rotational frequency shifts in partially coherent optical fields.

We study the frequency shifts taking place when a random, stationary optical field rotates with respect to an observer. The field is expanded in terms of fully coherent Laguerre-Gaussian basis modes, for which the rotational frequency shifts have been studied previously. We demonstrate the formalism by considering the spectrum of a Gaussian Schell-model field, and show that for a spatially highly incoherent field, significant spectral changes can be expected.

Journal Article↗
PubMed1993

The sensing of rotational and translational optic flow by the primate optokinetic system.

In primates, there are several reflexes that generate eye movements to compensate for the observer's own movements. Two vestibuloocular reflexes compensate selectively for rotational (RVOR) and translational (TVOR) disturbances of the head, receiving their inputs from the semi-circular canals and otolith organs, respectively. Two independent visual tracking systems deal with any residual disturbances of gaze (global optic flow) and are manifest in the two components of the optokinetic response: the indirect or delayed component (OKNd) and the direct or early component (OKNe). I hypothesize that OKNd--like the RVOR--is phylogenetically old, being found in all animals with mobile eyes, and that it evolved as a backup to the RVOR to compensate for residual rotational disturbances of gaze. Indeed, optically induced changes in the gain of the RVOR result in parallel changes in the gain of OKNd, consistent with the idea of shared pathways as well as shared functions. In contrast, OKNe seems to have evolved much more recently in frontal-eyed animals and, I suggest, acts as a backup to the TVOR--also recently evolved?--to deal primarily with translational disturbances of gaze. Frontal-eyed animals with good binocular vision must be able to keep both eyes directed at the object of regard irrespective of proximity and, in order to achieve this during translational disturbances, the output of the TVOR is modulated inversely with the viewing distance. This sensitivity to absolute depth is also shared by OKNe, consistent with the idea that OKNe is synergistic with the TVOR and shares some of its central pathways. There is evidence that OKNe is also sensitive to relative depth cues such as motion parallax and disparity, which I suggest help the system to segregate the object of regard from other elements in the scene. I also suggest that highly complex optic flow patterns (such as those experienced by the moving observer who looks a little off to one side of his direction of heading) are dealt with by a third visual tracking mechanism--the smooth pursuit system--that spatially filters visual motion inputs so as to exclude all but the motion of the object of interest (local optic flow).

Animals↗
PubMed2000

Forced molecular rotation in an optical centrifuge.

Intense linearly polarized light induces a dipole force that aligns an anisotropic molecule to the direction of the field polarization. Rotating the polarization causes the molecule to rotate. Using femtosecond laser technology, we accelerate the rate of rotation from 0 to 6 THz in 50 ps, spinning chlorine molecules from near rest up to angular momentum states J approximately 420. At the highest spinning rate, the molecular bond is broken and the molecule dissociates.

Journal Article↗
PubMed2004

Direct manipulation and observation of the rotational motion of single optically trapped microparticles and biological cells in microvortices.

This paper describes a method for manipulating and monitoring the rotational motion of single, optically trapped microparticles and living cells in a microvortex. To induce rotation, we placed the microparticle at the center of rotation of the vortex and used the recirculating fluid flow to drive rotation. We have monitored the rotation of single beads (which ranged in diameter from a few micrometers to tens of micrometers) and living cells in a microvortex. To follow the rotation of a smooth and symmetrically shaped bead, we first ablated a small region ( approximately 1 microm) on the bead. An Ar(+) laser was then tightly focused ( approximately 0.5-microm spot size) onto the bead, and rotation was tracked by recording changes in the level of backscattered laser light as the ablated region repeatedly transited the laser focus. Using this method, we have followed bead rotation that varied in frequency from 0.15 to 100 Hz and have studied the effect of bead diameter on the rate of rotation at a given fluid flow rate. To monitor the rotation of single living cells, we selectively stained portions of B-lymphocytes with the fluorescent dye DiOC(6). We observed rotation by following changes in the fluorescence signal as the dye-stained region transited the laser focal volume. This technique provides a simple and sensitive method for controlling and monitoring the rotational motion of microparticles in a microfluidic environment.

Animals↗
PubMed2003

Controlled rotation of biological microscopic objects using optical line tweezers.

Controlled, continuous rotation of cells or intracellular objects was achieved using optical tweezers with an elliptic beam profile (line tweezers), which was generated by placing a cylindrical lens in the path of the trapping beam. By rotating the cylindrical lens, rotation of the elliptic trapping beam and hence of the object trapped therein was achieved. Compared to previously reported techniques for rotation of microscopic objects, this approach is much simpler, gives better utilization of available laser power and also allows much easier control of the trap beam profile. We have used this approach for rotation of biological objects varying in size from 2 to 40 microm. At 25 mW trapping beam power at the object plane E. coli bacteria could be rotated at speeds approaching 10 Hz and an intracellular object (presumably a calcium oxalate crystal) trapped inside Elodea densa plant cell could be rotated with speeds of up to 4 Hz. To our knowledge, this is the first report for rotation of an intracellular object.

Cell Movement↗
PubMed2006

Polarization and image rotation induced by a rotating dielectric rod: an optical angular momentum interpretation.

When light is transmitted along the axis of a rotating glass rod, the polarization of the light is rotated through a small angle [Proc. R. Soc. London, Ser. A349, 423 (1976)]. Under the same conditions, we predict a rotation of the transmitted image by exactly the same angle. The treatment of the two effects in terms of light's spin and orbital angular momentum suggests that they share a common origin.

Journal Article↗
PubMed2002

A personal-computer-based method to obtain "star-shots" of mechanical and optical isocenters for gantry rotation of linear accelerators.

This work describes a method to obtain "star-shots" of the mechanical and optical isocenters of linear accelerators, similar to the star-shots of radiation isocenters normally obtained using films. In this method a digital camera is connected to a personal computer so that multiply exposed images can be taken at a fixed camera position. A mechanical pointer or a wire aligned along the optical axis can then be imaged by the camera. Multiple exposures at varying gantry angles are then superimposed on a digital image which can be analyzed by the computer to give a high-resolution star-shot. The method provides a convenient way for a linear accelerator quality assurance procedure.

Computer Simulation↗
PubMed2003

Optical control of the rotational angular momentum of a molecular Rydberg wave packet.

An intuitive scheme for controlling the rotational quantum state of a Rydberg molecule is demonstrated experimentally. We determine the accumulated phase difference between the various components of a molecular electron wave packet, and then employ a sequence of phase-locked optical pulses to selectively enhance or depopulate specific rotational states. The angular momentum composition of the resulting wave packet, and the efficiency of the control scheme, is determined by calculating the multipulse response of the time-dependent Rydberg populations.

Feedback↗
PubMed1994

Influence of passive and active pendular head rotation on horizontal optokinetic nystagmus.

The influence of pendular head rotation on optokinetic nystagmus was examined using a vestibulo-optic stimulator (pendular rotating chair with an optic cylinder) to study passive head rotation, and an optic cylinder which was rotated by a motor fixed to the head to study active head rotation. Pendular head rotation and optic stimuli were simultaneously and independently applied horizontally. The optic cylinder consisted of 12 vertical stripes rotating at a uniform velocity of 30 degrees/s or 90 degrees/s. Passive pendular head rotation was applied at a frequency of 0.1 Hz and a peak angular velocity of 30 degrees/s. Active head rotation was applied for a period of approximately 10 s, and at an amplitude of approximately 50 degrees. Optokinetic nystagmus was enhanced when the head was rotated in the opposite direction to the optic cylinder. However, when the head and the optic cylinder were rotated in the same direction, optokinetic nystagmus was inhibited. There was little difference between the effects of passive and active head rotation on enhancement. However, during active head rotation, optokinetic nystagmus was less inhibited than during passive head rotation.

Adult↗