Seungwoo Noh

Mesolimbic dopaminergic activity responding to acute stress is blunted in adolescent rats that experienced neonatal maternal separation

Neonatal maternal separation (MS), stressful experience early in life, leads to the development of depression-like behaviors in the offspring later in life. This study was conducted to define the neural basis of depression-like behaviors observed in our MS model. Sprague-Dawley pups were separated from dam for 3 h daily during the first 2 weeks of birth (MS) or left undisturbed (NH). All pups were sacrificed on postnatal day 41 with/without 1 h of restraint stress. Restraint stress significantly increased c-Fos expression in the nucleus accumbens (NAcb) of NH pups, but not in MS. In NH pups, restraint stress increased dopamine levels not only in the NAcb but also in the midbrain dopamine neurons; however, these increases were not observed in MS. Gene expression of tyrosine hydroxylase (TH) in the ventral tegmental area (VTA) was increased by acute restraint in NH pups, but not in MS pups. The raphe serotonin level was lower in MS than in NH, and not significantly changed by acute restraint neither in NH nor in MS. Results reveal that experience of neonatal MS may lead to a long-term suppression in the mesolimbic dopamine system of the offspring later in life, in which an epigenetic control may be implicated, such as suppressed gene expression of TH in the midbrain. We conclude that a decreased activity of the mesolimbic dopamine system may play a role in the pathophysiology of depression-like behaviors by neonatal MS, in addition to a decreased serotonin level in the raphe nucleus.

Registration of finger vein image using skin surface information for authentication

The finger vein image acquired with an acquisition system should be properly aligned to proceed with comparing algorithm. However it is not easy to find control the points since the images are naturally blurred with an inherent scattering property. To overcome this problem, we propose a novel finger vein registration method utilizing skin surface information (i.e. wrinkles and outlines). We assumed that finger crooking was insignificant. Images were sampled with intended translation and rotation. Each time, two images were acquired successively by switching the light source; one with infrared light and the other with white light. Degree of rotation and translation of sampled image were calculated using outline features in the white light image and then the infrared image was transformed according to the calculated data. To validate our method, correlation values were computed between identical subjects and different subjects. High correlation values were shown between identical subjects whereas low values were shown between different subjects.

Non-contact finger vein acquisition system using NIR laser

Authentication using finger vein pattern has substantial advantage than other biometrics. Because human vein patterns are hidden inside the skin and tissue, it is hard to forge vein structure. But conventional system using NIR LED array has two drawbacks. First, direct contact with LED array raise sanitary problem. Second, because of discreteness of LEDs, non-uniform illumination exists. We propose non-contact finger vein acquisition system using NIR laser and Laser line generator lens. Laser line generator lens makes evenly distributed line laser from focused laser light. Line laser is aimed on the finger longitudinally. NIR camera was used for image acquisition. 200 index finger vein images from 20 candidates are collected. Same finger vein pattern extraction algorithm was used to evaluate two sets of images. Acquired images from proposed non-contact system do not show any non-uniform illumination in contrary with conventional system. Also results of matching are comparable to conventional system. We developed Non-contact finger vein acquisition system. It can prevent potential cross contamination of skin diseases. Also the system can produce uniformly illuminated images unlike conventional system. With the benefit of non-contact, proposed system shows almost equivalent performance compared with conventional system.

Smartphone-Based Urine Reagent Strip Test in the Emergency Department

BACKGROUND Although a smartphone could be used for a urine reagent strip test, few studies have reported on the reliability of the test in a clinical setting. The objective of our study was to access the smartphone-based urine reagent strip test in the clinical emergency department (ED). MATERIALS AND METHODS We developed a smartphone-based urine reagent strip reader for a rapid and accurate screening of leukocyte esterase (LE) and nitrite (NIT) in urine. The developed reader was evaluated with the clinical urine samples (n = 81). The detection performance of the reader for LE and NIT was evaluated to assess reliability of the reader; turnaround times (TATs) for analysis and the time for the entire study procedure were also calculated to assess the efficiency of the reader. A photometric analyzer (model US-3100R Plus(®); Eiken Chemical, Ltd., Tokyo, Japan) was used as a reference. RESULTS The proposed reader showed high accuracy (85.2% for LE and 97.5% for NIT), exhibiting close agreement with the true values (κ = 0.903 for LE; κ = 1.000 for NIT). The reader also exhibited a lower median TAT for analysis than the photometric analyzer (3.0 min versus 33.0 min; p < 0.001). This reduction of TAT in the reader was even more evident considering the required time for delivery of urine samples for the photometric analyzer (3.0 min versus 62.0 min; p < 0.001). CONCLUSIONS Our results demonstrated the clinical capability of a smartphone-based urine reagent strip test, and this reader is expected to enable a more rapid and reliable colorimetric test for screening of LE and NIT at the clinical setting and the point of care.

Tool to visualize and evaluate operator proficiency in laser hair-removal treatments

BackgroundThe uniform delivery of laser energy is particularly important for safe and effective laser hair removal (LHR) treatment. Although it is necessary to quantitatively assess the spatial distribution of the delivered laser, laser spots are difficult to trace owing to a lack of visual cues. This study proposes a novel preclinic tool to evaluate operator proficiency in LHR treatment and applies this tool to train novice operators and compare two different treatment techniques (sliding versus spot-by-spot).MethodsA simulation bed is constructed to visualize the irradiated laser spots. Six novice operators are recruited to perform four sessions of simulation while changing the treatment techniques and the presence of feedback (sliding without feedback, sliding with feedback, spot-by-spot without feedback, and spot-by-spot with feedback). Laser distribution maps (LDMs) are reconstructed through a series of images processed from the recorded video for each simulation session. Then, an experienced dermatologist classifies the collected LDMs into three different performance groups, which are quantitatively analyzed in terms of four performance indices.ResultsThe performance groups are characterized by using a combination of four proposed indices. The best-performing group exhibited the lowest amount of randomness in laser delivery and accurate estimation of mean spot distances. The training was only effective in the sliding treatment technique. After the training, omission errors decreased by 6.32% and better estimation of the mean spot distance of the actual size of the laser-emitting window was achieved. Gels required operators to be trained when the spot-by-spot technique was used, and imposed difficulties in maintaining regular laser delivery when the sliding technique was used.ConclusionsBecause the proposed system is simple and highly affordable, it is expected to benefit many operators in clinics to train and maintain skilled performance in LHR treatment, which will eventually lead to accomplishing a uniform laser delivery for safe and effective LHR treatment.

A grip force model for the da Vinci end-effector to predict a compensation force

A torque transfer system (TTS) that measures grip forces is developed to resolve a potential drawback of the current da Vinci robot system whose grip forces vary according to the different postures of its EndoWrist. A preliminary model of EndoWrist Inner Mechanism Model (EIMM) is also developed and validated with real grip force measurements. EndoWrist’s grip forces, posture angles, and transferred torque are measured by using TTS. The mean measured grip forces of three different EndoWrist for 27 different postures were very diverse. The EndoWrist exerted different grip forces, with a minimum of 1.84-times more and a maximum of 3.37-times more in specific posture even if the surgeon exerted the same amount of force. Using the posture angles as input and the grip forces as output, the EIMM is constructed. Then, expected grip force values obtained from EIMM are compared with actual measurements of da Vinci EndoWrist to validate the proposed model. From these results, surgeons will be beneficial with the understandings of actual grip force being applied to tissue and mechanical properties of robotic system. The EIMM could provide a baseline in designing a force-feedback system for surgical robot. These are significantly important to prevent serious injury by maintaining a proper force to tissue.

Patch type integrated sensor system for measuring electrical and mechanical cardiac activities

The ElectroMechanical Film (EMFi), a thin and flexible piezoelectric material, has been widely used as a mechanical sensor or actuator. Especially in Biomedical Engineering field, many researchers have used EMFi for measuring ballistocardiogram (BCG) which is a mechanical signal caused by blood ejection from heart. However, previous methods required special equipments installed on a chair or a bed to measure BCG. In this preliminary study, we designed a flexible patch type sensor that can measure electrical and mechanical signal simultaneously on a single unit. The Ballistocardiogram-Electrocardiogram patch (BEpatch), integrated with flexible circuit and attached to chest, can successfully measure fine electrocardiogram (ECG) and BCG signals simultaneously. The result shows that BEpatch can be used for continuous monitoring of bio-signals in a simple and comfortable manner, thereby, advantageous as a wearable health care device.

Influence of the washing program on the blood processing performance of a continuous autotransfusion device.

The continuous autotransfusion system has been widely used in surgical operations. It is known that if oil is added to blood, and this mixture is then processed by an autotransfusion device, the added oil is removed and reinfusion of fat is prevented by the device. However, there is no detailed report on the influence of the particular washing program selected on the levels of blood components including blood fat after continuous autotransfusion using such a system. Fresh bovine blood samples were processed by a commercial continuous autotransfusion device using the “emergency,” “quality,” and “high-quality” programs, applied in random order. Complete blood count (CBC) and serum chemistry were analyzed to determine how the blood processing performance of the device changes with the washing program applied. There was no significant difference in the CBC results obtained with the three washing programs. Although all of the blood lipids in the processed blood were decreased compared to those in the blood before processing, the levels of triglyceride, phospholipid, and total cholesterol after processing via the emergency program were significantly higher than those present after processing via the quality and high-quality programs. Although the continuous autotransfusion device provided consistent hematocrit quality, the levels of some blood lipid components showed significant differences among the washing programs.