Optical image Formation in terms of entropy transformations and intensity matrices.

Thesis (M.A.)--Boston UniversityThe entropy concepts in thermodynamics, statistical mechanics, information theory and optics are discussed along with their relationships. As a first step of the application of the entropy concept we evaluate the entropy loss in optical system (one- and two-dimensional cases) vs. defocussing from geometrical and physical optics viewpoints. After reviewing the image formation with Fourier analysis and bringing it to a general formulation, we consider the foundations of the optical image formulation in terms of matrices and apply it to several illustrative cases. We investigate the properties of the illumination matrix of optics proposed by Gabor and Gamo under the guidance of statistical mechanical density matrix. Comparison between the density matrix and the illumination matrix is considered. [TRUNCATED

The Tokyo Oldest Old Survey on Total Health (TOOTH): A longitudinal cohort study of multidimensional components of health and well-being

<p>Abstract</p> <p>Background</p> <p>With the rapid worldwide increase in the oldest old population, considerable concern has arisen about the social and economic burden of diseases and disability in this age group. Understanding of multidimensional structure of health and its life-course trajectory is an essential prerequisite for effective health care delivery. Therefore, we organized an interdisciplinary research team consisting of geriatricians, dentists, psychologists, sociologists, and epidemiologists to conduct a longitudinal observational study.</p> <p>Methods/Design</p> <p>For the Tokyo Oldest Old Survey on Total Health (TOOTH) study, a random sample of inhabitants of the city of Tokyo, aged 85 years or older, was drawn from the basic city registry. The baseline comprehensive assessment consists of an in-home interview, a self-administered questionnaire, and a medical/dental examination. To perform a wide variety of biomedical measurements, including carotid ultrasonography and a detailed dental examination, participants were invited to our study center at Keio University Hospital. For those who were not able to visit the study center, we provided the option of a home-based examination, in which participants were simultaneously visited by a geriatrician and a dentist. Of 2875 eligible individuals, a total of 1152 people were recruited, of which 542 completed both the in-home interview and the medical/dental examination, with 442 completed the in-home interview only, and another 168 completed self or proxy-administered data collection only. Carotid ultrasonography was completed in 458 subjects, which was 99.6% of the clinic visitors (n = 460). Masticatory assessment using a colour-changeable chewing gum was completed in 421 subjects, a 91.5% of the clinic visitors.</p> <p>Discussion</p> <p>Our results demonstrated the feasibility of a new comprehensive study that incorporated non-invasive measurements of subclinical diseases and a detailed dental examination aiming at community-dwelling individuals aged 85 years or older. The bimodal recruitment strategy is critically important to capture a broad range of health profiles among the oldest old. Results form the TOOTH study will help develop new models of health promotion, which are expected to contribute to an improvement in lifelong health and well-being.</p> <p>Trial Registration</p> <p>This study has been registered in the UMIN-Clinical Trial Registry (CTR), ID: UMIN000001842.</p

Low-Dose Intravenous Alteplase in Wake-Up Stroke

Background and Purpose—We assessed whether lower-dose alteplase at 0.6 mg/kg is efficacious and safe for acute fluid-attenuated inversion recovery-negative stroke with unknown time of onset. Methods—This was an investigator-initiated, multicenter, randomized, open-label, blinded-end point trial. Patients met the standard indication criteria for intravenous thrombolysis other than a time last-known-well >4.5 hours (eg, wake-up stroke). Patients were randomly assigned (1:1) to receive alteplase at 0.6 mg/kg or standard medical treatment if magnetic resonance imaging showed acute ischemic lesion on diffusion-weighted imaging and no marked corresponding hyperintensity on fluid-attenuated inversion recovery. The primary outcome was a favorable outcome (90-day modified Rankin Scale score of 0–1). Results—Following the early stop and positive results of the WAKE-UP trial (Efficacy and Safety of MRI-Based Thrombolysis in Wake-Up Stroke), this trial was prematurely terminated with 131 of the anticipated 300 patients (55 women; mean age, 74.4±12.2 years). Favorable outcome was comparable between the alteplase group (32/68, 47.1%) and the control group (28/58, 48.3%; relative risk [RR], 0.97 [95% CI, 0.68–1.41]; P=0.892). Symptomatic intracranial hemorrhage within 22 to 36 hours occurred in 1/71 and 0/60 (RR, infinity [95% CI, 0.06 to infinity]; P>0.999), respectively. Death at 90 days occurred in 2/71 and 2/60 (RR, 0.85 [95% CI, 0.06–12.58]; P>0.999), respectively. Conclusions—No difference in favorable outcome was seen between alteplase and control groups among patients with ischemic stroke with unknown time of onset. The safety of alteplase at 0.6 mg/kg was comparable to that of standard treatment. Early study termination precludes any definitive conclusions

Photon Pathlengths And Polarization Effects In Scattering Of Light In Turbid Media

Light backscattered from turbid media in the crossed-polarized channel shows symmetrical pattern. It depends on the pathlengths distribution of the multiply scattered photons. The present paper investigates the relation between the cross-polarized backscattered light and the number of collisions experienced by photons in a narrow beam geometry

Spatial Filtering Velocimetry: Fundamentals and Applications

The first monograph devoted exclusively to spatial filtering velocimetry, this book includes fundamental theory, imaging optics, signal analysis, spatial filtering devices and systems, plus applications. Also suitable as a tutorial for students and users who are unfamiliar with optics and signal processing, Spatial Filtering Velocimetry treats the principle and properties of this velocimetric technique in a concise and easily readable form, together with full appendices. The book reviews a wide range of systems and applications of the spatial-filtering technique for velocity and related measurements, putting forth examples useful in various fields of science, medicine, and engineering

Polarized Light Scattering In Dielectric Layers With Rough Interfaces

The polarization behavior of light backscattered from layers with random rough interfaces is investigated in a narrow beam geometry. A simple explanation is given for the appearance of four-fold symmetrical polarization patterns in the geometric-optics limit. Multiple scattering sequences are found to be the origin of the observed polarization behavior. Numerical ray-tracing experiments correctly predict the polarization patterns