Light Transport Refocusing for Unknown Scattering Medium

2014 22nd International Conference on Pattern Recognition,Stockholm, Sweden,24-28 Aug. 2014In this paper we propose a new light transport refocusing method for depth estimation as well as for investigation inside scattering media with unknown scattering properties. Propagated visible light rays through scattering media are utilized in our proposed refocusing method. We use 2D light source to illuminate the scattering media and 2D image sensor for capturing transported rays. The proposed method that uses 4D light transport can clearly visualize shallow depth, as well as deep depth plane of the medium. We apply our light transport refocusing method for depth estimation using conventional depth-from-focus method and for clear visualization by descattering the light rays passing through the medium. To evaluate the effectiveness we have done experiments using acrylic and milk-water type scattering medium in various optical and geometrical conditions. Finally, we show up the results of depth estimation and clear visualization, as well as with numeric evaluation

Is Presence or History of Extracolonic Primary Malignancy a Risk for Colorectal Neoplasia? An Analysis of Patients Who Underwent Colonoscopy

Whether presence or history of extracolonic primary malignancy is a risk for colorectal neoplasia is not fully known. In this study, 26,452 first-time colonoscopy cases were examined using a colonoscopy database. Among the analyzed subjects, 3,026 (11%) subjects had history or concomitance of extracolonic primary malignancy, while the remaining 23,426 subjects did not. Colorectal neoplasia was observed in 39% of all the subjects. A crude comparison showed that the prevalence of any type of colorectal neoplasia was higher in subjects with extracolonic malignancy than in those without (42% vs. 39%, p＝0.0012). However, after adjusting for confounding factors, the odds ratios (ORs) of subjects with extracolonic malignancy for having colorectal neoplasia, advanced neoplasia, and cancer were all less than 1.0, and all significantly different from those of subjects without extracolonic malignancy. Analysis according to the type of extracolonic malignancy revealed that gastric cancer cases had a significantly lower risk for colorectal advanced neoplasia (OR:0.81;95% CI:0.67-0.99). Among major malignancies, only esophageal squamous cell cancer cases had increased risk for colorectal neoplasia (OR:1.66;95% CI:1.20-2.29). Patients with presence or history of extracolonic malignancy did not carry a higher risk of occurrence of colorectal neoplasia

Effects of topical latanoprost on optic nerve head circulation in rabbits, monkeys

PURPOSE. To evaluate the effect of topically administrated latanoprost on optic nerve head (ONH) circulation in Dutch rabbits, cynomolgus monkeys, and normal humans. METHODS. The ONH tissue blood velocity (NB ONH ) was determined using the laser speckle method. Latanoprost (0.005%, 30 l) was instilled into one eye, and vehicle into the other eye as a control. In rabbits, NB ONH was measured for 90 minutes after a single instillation and before and after a 7-day once-daily instillation regimen. In monkeys, NB ONH was measured before and after 1, 4, and 7 days of a once-daily instillation regimen. The effect of intravenous indomethacin on the latanoprostinduced NB ONH change was also studied in rabbits and monkeys. In humans, the time-course changes in NB ONH were measured for 4.5 hours before and after a 7-day once-daily instillation regimen. Intraocular pressure (IOP) and systemic parameters were simultaneously studied in each experiment. All measurements were performed by investigators masked to the experimental condition. RESULTS. Latanoprost significantly increased NB ONH 10% to 19% in treated eyes after a single instillation (P ϭ 0.035) or 7-day instillation regimen (P ϭ 0.035) in rabbits, after a 4-day (P ϭ 0.035) or 7-day (P ϭ 0.035) instillation regimen in monkeys, and after a 7-day (P ϭ 0.013) instillation regimen in humans, whereas there were no significant changes in the vehicletreated eyes in any of the experiments (P Ͼ 0.5). Pretreatment with indomethacin (5 mg/kg) abolished the NB ONH increase but not the IOP reduction in latanoprost-treated eyes in rabbits and monkeys. IOP remained unchanged in both eyes in rabbits (P Ͼ 0.4), whereas it significantly decreased only in latanoprost-treated eyes in monkeys (P Ͻ 0.05) and humans (P Ͻ 0.05). CONCLUSIONS. Topical latanoprost significantly increased ONH blood velocity only in treated eyes in rabbits, monkeys, and humans. This effect was independent of the IOP-reducing effect of latanoprost and probably was associated with local penetration of the drug and the production of endogenous prostaglandins. (Invest Ophthalmol Vis Sci. 2001;42:2957-2963 L atanoprost, a recently developed prostaglandin F 2␣ (PGF 2␣ )-related FP receptor agonist compound, 1 is one of the most potent ocular hypotensive eye drops in patients with glaucoma. 2-8 Although intraocular pressure (IOP) is consistently the major risk factor for glaucoma, recent studies indicate that impaired circulation in the optic nerve head (ONH) has a crucial role in glaucomatous optic neuropathy. -11 Previous studies have suggested that topically instilled timolol or betaxolol over a long period can accumulate in the periocular tissues and reach the retrobulbar space in sufficient concentration to have pharmacologic effects on the retrobulbar vessels. 12-14 PGF 2␣ has vasoconstricting or vasodilating effects, depending on its concentration, the nature of the vascular bed, or the animal species. 15-18 Latanoprost also has vasoconstricting effects at higher concentrations 20 Grunwald 21-23 and Gupta et al. In the present study, we examined the effects of not only a single instillation but also a 7-day once-daily instillation regimen of latanoprost on ONH circulation in rabbits, monkeys, and normal humans, by using the noninvasive laser speckle method. MATERIALS AND METHODS Instruments ONH circulation was evaluated using the laser speckle method

Exploring Transduction Mechanisms of Protein Transduction Domains (PTDs) in Living Cells Utilizing Single-Quantum Dot Tracking (SQT) Technology

Specific protein domains known as protein transduction domains (PTDs) can permeate cell membranes and deliver proteins or bioactive materials into living cells. Various approaches have been applied for improving their transduction efficacy. It is, therefore, crucial to clarify the entry mechanisms and to identify the rate-limiting steps. Because of technical limitations for imaging PTD behavior on cells with conventional fluorescent-dyes, how PTDs enter the cells has been a topic of much debate. Utilizing quantum dots (QDs), we recently tracked the behavior of PTD that was derived from HIV-1 Tat (TatP) in living cells at the single-molecule level with 7-nm special precision. In this review article, we initially summarize the controversy on TatP entry mechanisms; thereafter, we will focus on our recent findings on single-TatP-QD tracking (SQT), to identify the major sequential steps of intracellular delivery in living cells and to discuss how SQT can easily provide direct information on TatP entry mechanisms. As a primer for SQT study, we also discuss the latest findings on single particle tracking of various molecules on the plasma membrane. Finally, we discuss the problems of QDs and the challenges for the future in utilizing currently available QD probes for SQT. In conclusion, direct identification of the rate-limiting steps of PTD entry with SQT should dramatically improve the methods for enhancing transduction efficiency

Orientation-Compensative Signal Registration for Owner Authentication Using an Accelerometer

Gait-based owner authentication using accelerometers has recently been extensively studied owing to the development of wearable electronic devices. An actual gait signal is always subject to change due to many factors including variation of sensor attachment. In this research, we tackle to the practical sensor-orientation inconsistency, for which signal sequences are captured at different sensor orientations. We present an iterative signal matching algorithm based on phase-registration technique to simultaneously estimate relative sensor-orientation and register the 3D acceleration signals. The iterative framework is initialized by using 1D orientation-invariant resultant signals which are computed from 3D signals. As a result, the matching algorithm is robust to any initial sensor-orientation. This matching algorithm is used to match a probe and a gallery signals in the proposed owner authentication method. Experiments using actual gait signals under various conditions such as different days, sensors, weights being carried, and sensor orientations show that our authentication method achieves positive results