Review—Lab-in-a-Mouth and Advanced Point-of-Care Sensing Systems: Detecting Bioinformation from the Oral Cavity and Saliva

Cavitas sensors and point-of-need sensors capable of providing physical and biochemical information from the oral cavity and saliva have attracted great attention because they offer remarkable advantages for noninvasive sensing systems. Herein, we introduce the basic anatomy and physiology of important body cavities to understand their characteristics as it is a pivotal foundation for the successful development of in-mouth devices. Next, the advanced development in lab-in-a-mouth sensors and point-of-need sensors for analyzing saliva are explained. In addition, we discuss the integrations of artificial intelligence and electronic technologies in smart sensing networks for healthcare systems. This review ends with a discussion of the challenges, future research trends, and opportunities in relevant disciplines. Mouthguard-based sensors and conventional salivary sensing devices will continue to be significant for the progress in the next-generation sensing technologies and smart healthcare systems.ope

Wireless Non-Invasive Monitoring of Cholesterol Using a Smart Contact Lens

Herein, a wireless and soft smart contact lens that enables real-time quantitative recording of cholesterol in tear fluids for the monitoring of patients with hyperlipidemia using a smartphone is reported. This contact lens incorporates an electrochemical biosensor for the continuous detection of cholesterol concentrations, stretchable antenna, and integrated circuits for wireless communication, which makes a smartphone the only device required to operate this lens remotely without obstructing the wearer's vision. The hyperlipidemia rabbit model is utilized to confirm the correlation between cholesterol levels in tear fluid and blood and to confirm the feasibility of this smart contact lens for diagnostic application of cholesterol-related diseases. Further in vivo tests with human subjects demonstrated its good biocompatibility, wearability, and reliability as a non-invasive healthcare device.ope

Expression, distribution and cellular localization of Sirtuins in the normal and ischemic brain of rodent

의과대학/석사Sirtuins (SIRTs) are nicotinamide adenine dinucleotide-dependent histone deacetylases. To date, seven sirtuins (SIRT1-SIRT7) have been identified in mammals. While basic knowledge of sirtuins in the brain is essential to understand the role of sirtuins in the normal and pathologic brain, only limited information is available. We investigated the distribution and cellular localization of sirtuins in the normal and ischemic brain of the rodent. Male Sprague-Dawley (SD) rats, Wistar rats, Imprinting Control Region (ICR) mice, and C57BL/6 mice were used. Normal whole brain samples were obtained. In paraffin or frozen sections, immunohistochemistry was performed and the whole brain was examined into regions: olfactory bulb, cerebrum and cerebellum. To examine the cell types that express sirtuins, double immunofluorescence staining was performed using antibodies for each sirtuin and those for specific cell markers. Cerebral ischemia induced by 2 hr of middle cerebral artery occlusion and 22 hr of reperfusion using nylon thread. The expression of each sirtuin was compared between normal and ischemic brain areas. SIRT1, SIRT3 and SIRT5-7 were expressed in neurons of most of regions and in oligodendrocytes of corpus callosum and internal capsule. SIRT2 was expressed in myelin. SIRT4 was expressed in vessels. As a result, sirtuins, especially SIRT5-7 were widely distributed and highly expressed in the olfactory bulb, cerebrum, and cerebellum. The expression of SIRT1 and SIRT3 in the corpus callosum and internal capsule was variable among species. SIRT2 was not expressed in the external plexiform layer of olfactory bulb and hypothalamus of cerebrum. SIRT4 was widely expressed in the entire brain areas except in the purkinje layer of cerebellum in SD rats. After induction of cerebral ischemia, SIRT4 showed significantly increased expression in the ischemic region. However, the other sirtuins were not significantly different. Distribution and cellular localization in the rodent brain were different among sirtuins. Expression in the ischemic brain was also different. Findings of this study might provide with basic information for studying pathophysiologic role of sirtuins in the brain.ope

제2외국어로서 영어와 한국어 폐쇄음 산출과 인지 연구

This study examines how L1 Korean learners of L2 English and L1 English learners of L2 Korean produce L2 stops in terms of voice onset time (VOT) and fundamental frequency (F0) and how they perceive L2 stops. The study also examines how the level of L2 proficiency functions as a critical factor in determining the L1-to-L2 influence. Two findings were derived from production experiments. First, the primary acoustic cues of L1 stops are negatively transferred to the production of L2 stops in L2 beginners. Second, advanced L2 learners acquire the primary cues of L2 stops. These results indicate that the acquisition of L2 stops is regulated by the different priority order of VOT and F0 between L1 and L2 stops and learners' L2 proficiency. Furthermore, the results of production and perception experiments suggest that the perception of L2 stops precedes the production of L2 stops. (Chonnam National University

Thyroid Cancer Staging.

The current prevalence of thyroid cancer in women is high. Likewise, other cancers and thyroid cancer have been based on the TNM classification system. Staging of thyroid cancer has an important role in determining the extent of surgical excision and lymph node dissection, planning the adjuvant therapy after surgery and predicting the recurrence rate and the prognosis of patients. Ultrasonography is the basic imaging modality to identify the tumor size and the extent of lymph node metastasis. More recently, computed tomography, magnetic resonance imaging and positron emission tomography provide additional help for the staging of thyroid cancer. So, this article describes the 7th edition of the TNM staging of thyroid cancer, as proposed by the American Joint Committee on Cancer, and the details of radiologic evaluation of the T, N and M stagesope

Conventional papillary thyroid carcinoma: effects of cystic changes visible on ultrasonography on disease prognosis

PURPOSE: To investigate the characteristics of papillary thyroid carcinoma (PTC) with cystic changes visible on ultrasonography (US). METHODS: This study included 553 PTCs in 553 patients between January 2003 and August 2004. One radiologist with 10 years of experience in thyroid imaging retrospectively reviewed the preoperative US images. Two different groups were formed according to two different reference points (group 1, 25%; group 2, 50%) of the cystic component. Patients between the groups were compared according to their clinicopathologic characteristics. Disease-free survival (DFS) was estimated. Cox's multivariate proportional hazards regression model was used to identify the effect of variable factors on the recurrence risk. RESULTS: Fifty-six patients (10.1%) were confirmed to have tumor recurrence within the follow-up period. Thirty-five patients had regional metastasis, one had distant metastasis, eight had multiple site metastases, and 12 had biochemical recurrence. PTC patients with a ≤ 50% or PTC patients with a ≤ 25% cystic component did not have a statistically significant longer DFS than those with a >50% (hazard ratio [HR], 1.118; 95% confidence interval [CI], 0.255 to 4.910; P=0.883) or those with a >25% cystic component (HR, 0.569; 95% CI, 0.164 to 1.976; P=0.375), respectively. Moreover, independent predictors of recurrence were pathologic size, male gender, and lymph node metastasis, not a >50% or >25% cystic component. CONCLUSION: The proportion of the cystic component in PTCs did not affect DFS.ope

Effects of Mesenchymal Stem Cell Treatment on the Expression of Matrix Metalloproteinases and Angiogenesis during Ischemic Stroke Recovery

BACKGROUND: The efficacy of mesenchymal stem cell (MSC) transplantation in ischemic stroke might depend on the timing of administration. We investigated the optimal time point of MSC transplantation. After MSC treatment, we also investigated the expression of matrix metalloproteinases (MMPs), which play a role in vascular and tissue remodeling. METHODS: Human bone marrow-derived MSCs (2 × 10(6), passage 5) were administrated intravenously after permanent middle cerebral artery occlusion (MCAO) was induced in male Sprague-Dawley rats. First, we determined the time point of MSC transplantation that led to maximal neurological recovery at 1 h, 1 day, and 3 days after MCAO. Next, we measured activity of MMP-2 and MMP-9, neurological recovery, infarction volume, and vascular density after transplanting MSCs at the time that led to maximal neurological recovery. RESULTS: Among the MSC-transplanted rats, those of the MSC 1-hour group showed maximal recovery in the rotarod test (P = 0.023) and the Longa score (P = 0.018). MMP-2 activity at 1 day after MCAO in the MSC 1-hour group was significantly higher than that in the control group (P = 0.002), but MMP-9 activity was not distinct. The MSC 1-hour group also showed smaller infarction volume and higher vascular density than did the control group. CONCLUSIONS: In a permanent model of rodent MCAO, very early transplantation of human MSCs (1 h after MCAO) produced greater neurological recovery and decreased infraction volume. The elevation of MMP-2 activity and the increase in vascular density after MSC treatment suggest that MSCs might help promote angiogenesis and lead to neurological improvement during the recovery phase after ischemic stroke.ope

Introducing Nanoscale Electrochemistry in Small-Molecule Detection for Tackling Existing Limitations of Affinity-Based Label-Free Biosensing Applications

Electrochemical sensing techniques for small molecules have progressed in many applications, including disease diagnosis and prevention as well as monitoring of health conditions. However, affinity-based detection for low-abundance small molecules is still challenging due to the imbalance in target-to-receptor size ratio as well as the lack of a highly sensitive signal transducing method. Herein, we introduced nanoscale electrochemistry in affinity-based small molecule detection by measuring the change of quantum electrochemical properties with a nanoscale artificial receptor upon binding. We prepared a nanoscale molecularly imprinted composite polymer (MICP) for cortisol by electrochemically copolymerizing β-cyclodextrin and redox-active methylene blue to offer a high target-to-receptor size ratio, thus realizing "bind-and-read" detection of cortisol as a representative target small molecule, along with extremely high sensitivity. Using the quantum conductance measurement, the present MICP-based sensor can detect cortisol from 1.00 × 10-12 to 1.00 × 10-6 M with a detection limit of 3.93 × 10-13 M (S/N = 3), which is much lower than those obtained with other electrochemical methods. Moreover, the present MICP-based cortisol sensor exhibited reversible cortisol sensing capability through a simple electrochemical regeneration process without cumbersome steps of washing and solution change, which enables "continuous detection". In situ detection of cortisol in human saliva following circadian rhythm was carried out with the present MICP-based cortisol sensor, and the results were validated with the LC-MS/MS method. Consequently, this present cortisol sensor based on nanoscale MICP and quantum electrochemistry overcomes the limitations of affinity-based biosensors, opening up new possibilities for sensor applications in point-of-care and wearable healthcare devices.restrictio