Application of Non-Destructive Rapid Determination of Piperine in L. (Black Pepper) Using NIR and Multivariate Statistical Analysis: A Promising Quality Control Tool.

Piperine is a bioactive alkaloid compound which provides a unique spicy flavor derived from plants of the L. Black pepper ( = 160) collected from Vietnam was studied using non-destructive near infrared spectroscopy (NIRS). The spectral acquisition ranged from 1100 to 2500 nm, and a chemometrics analysis program was performed to quantify the piperine contents.

Feasibility of rapid piperine quantification in whole and black pepper using near infrared spectroscopy and chemometrics.

Piperine is a bioactive alkaloid that possesses various health benefits and is responsible for the pungent aroma of pepper. Piperine content in whole and ground black pepper (n = 132) was analyzed by near-infrared spectroscopy (NIRS) in the 950 to 1650 nm wavelength window. Chemometric modeling using partial least square regression was performed, and outliers were checked and removed during the preparation of the calibration curve by considering sample residual variance and sample leverage.

Improvement in Light Extraction Efficiency of InGaN/GaN Blue Light Emitting Diodes Using Sidewall Texturing.

Herein, we reported the effects of the geometric morphology of the sidewall on the extraction efficiency of GaN-based light-emitting diodes (LEDs). We performed numerical analysis based on the ray-tracing method. We found that the extraction efficiency of the LEDs increased with the texturing of the sidewall.

Responses of human sensory characteristics to 532 nm pulse laser stimuli.

Background: Lasers are advantageous in some applications to stimulate a small target area and is used in various fields such as optogenetic, photoimmunological and neurophysiological studies.

Objective: This study aims to implement a non-contact sense of touch without damaging biological tissues using laser.

Methods: Various laser parameters were utilized in safety range to induce a sense of touch and investigate the human responses.

Mid-Air Tactile Stimulation Using Indirect Laser Radiation.

In this paper, we demonstrate that a laser irradiated on a thin light-absorbing elastic medium attached on the skin can elicit a tactile sensation of mechanical tap. First, we present simulation results that show laser irradiation to the elastic medium creates inner elastic waves on the basis of thermoelastic effects and these elastic waves trigger the bending deformation of the medium, which then stimulates the skin. Second, we analyze the physical properties of the associated stimulus by measuring its force profile.

Photomechanical effect on Type I collagen using pulsed diode laser.

Background: As the most abundant protein in human tissues, the use of collagen is essential in the fields of biological science and medicine.

Objective: The aim of this study is to investigate the mechanical effect of pulsed laser irradiation on collagen tissue.

Methods: With various laser parameters such as peak power, pulse width, and repetition rate, the induced stresses on samples were measured and analyzed.

Evaluation of the possibility and response characteristics of laser-induced tactile sensation.

In this study, we examined the possibility and perceptual response characteristics of tactile sense induced by laser stimulation to the finger with different laser energy densities through human response experiments. 15 healthy adult males and 4 healthy adult females with an age of 22.6±2.

Laser-induced thermoelastic effects can evoke tactile sensations.

Humans process a plethora of sensory information that is provided by various entities in the surrounding environment. Among the five major senses, technology for touch, haptics, is relatively young and has relatively limited applications largely due to its need for physical contact. In this article, we suggest a new way for non-contact haptic stimulation that uses laser, which has potential advantages such as mid-air stimulation, high spatial precision, and long working distance.

Development of an optical fiber sensor for angular displacement measurements.

For diagnostic and therapeutic purposes, the joint angle measurement of a patient after an accident or a surgical operation is significant for monitoring and evaluating the recovering process. This paper proposed an optical fiber sensor for the measurement of angular displacement. The effect of beveled fiber angle on the detected light signal was investigated to find an appropriate mathematical model.

Development of a simple pressure and heat stimulator for intra- and interdigit functional magnetic resonance imaging.

For this study, we developed a simple pressure and heat stimulator that can quantitatively control pressure and provide heat stimulation to intra- and interdigit areas. The developed stimulator consists of a control unit, drive units, and tactors. The control unit controls the stimulation parameters, such as stimulation types, intensity, time, and channel, and transmits a created signal of stimulation to the drive units.

Development of a simple MR-compatible vibrotactile stimulator using a planar-coil-type actuator.

For this study, we developed a magnetic resonance (MR)-compatible vibrotactile stimulator using a planar-coil-type actuator. The newly developed vibrotactile stimulator consists of three units: control unit, drive unit, and planar-coil-type actuator. The control unit controls frequency, intensity, time, and channel, and transfers the stimulation signals to the drive unit.

Microscope system for Blu-ray disc samples.

We introduce a microscope system using a solid immersion lens (SIL) to image Blu-ray disc samples without removing the protective cover layer. The aberration caused by the cover layer is minimized with a truncated SIL. A subsurface imaging simulation is achieved by using the rigorous coupled wave theory, partial coherence, vector diffraction, and the Babinet principle.

High-numerical-aperture image simulation using Babinet's principle.

Simulation techniques are developed for high-numerical-aperture (NA) polarized microscopy with Babinet's principle, including partial coherence and vector diffraction for non-periodic geometries. The model includes vector illumination and diffraction in high-NA (up to NA=3.5) object space that is imaged into low-NA image space and recorded on an image sensor.

Development of a magnetic resonance-compatible galvanic skin response measurement system using optic signal.

The purpose of the current study is to develop a magnetic resonance (MR)-compatible galvanic skin response (GSR) measurement system that can measure the GSR signal during MR image acquisition. If GSR signals are measured simultaneously with the acquisition of MR images, there can be a mutual interference effect. The present system was designed to block noises caused by the main magnetic field, the gradient magnetic field, and the radio frequency (RF) pulse when MR images are acquired.

Direct reconstruction of an object from dual exposure Fourier intensity measurements.

The reconstruction of an object with a method using a dual exposure single inverse Fourier transform is investigated. The method calculates phase information in the Fourier plane to perform the inverse Fourier transform. The phase information in the Fourier plane is calculated from the intensity distributions formed by an object with and without a reference electric field.

Numerical simulation for light extraction in nano-patterned light-emitting diodes.

We present numerical simulation results using the three-dimensional finite-difference time-domain method for light extraction in light-emitting diodes (LEDs) constructed on nano-patterned n-GaN substrates. We studied reasonable conditions for numerical calculation, including excitation source conditions, simulation size conditions, and boundary conditions and examined the effects of the size and distribution of nano-patterns on light extraction. Our findings revealed optimized structures for high extraction efficiency.

A study on the cerebral sizes of Koreans in their 20S and 40S.

The purpose of this study was to measure the cerebral sizes of Korean adults in their third (20s) and fifth decades (40s) of life using Talairach-Nowinski reference points to determine the effect of sex and age on cerebral size and asymmetry. Magnetic resonance images of the brain of 94 adults between 20 and 29 years of age (43 males and 51 females) and 99 adults between 40 and 49 years of age (38 males and 61 females) were measured. The distance between reference points and cerebral size of males was greater than those of females.

Hyperfine structure measurement of rubidium atom and tunable diode laser stabilization by using Sagnac interferometer.

The Rubidium saturated absorption spectra for D2 transition lines are used to measure the Fabry-Perot interferometer free spectral range (FSR). The scale linearity of the laser frequency tuning is determined. The Sagnac interferometer has been used for the laser stabilization.