Guest editors introduce the special section of Journal of Biomedical Optics Volume 25, Issue 3, entitled "Biomedical Imaging and Sensing II," a collection of papers related to the topics of the conference "Biomedical Imaging and Sensing Conference 2019" (BISC'19), which was held in April 2019, in Yokohama, Japan.BACKGROUND Although the association of hyperuricemia with an increased risk of mortality has been demonstrated in the context of acute exacerbation of chronic obstructive pulmonary disease (COPD), the long-term outcomes of hyperuricemia have not been studied in the case of stable COPD. METHODS We retrospectively analyzed baseline data of 240 men with stable COPD enrolled in the Korea Obstructive Lung Disease cohort. We evaluated associations between serum uric acid levels and clinical parameters, risk factors for all-cause mortality, and acute exacerbation of COPD. RESULTS The mean age of subjects was 66.4 ± 7.7 years, and the median follow-up time was 5.9 years. We identified no significant difference in terms of lung function or laboratory findings between patients with hyperuricemia and those without. Serum uric acid level was negatively associated with systemic inflammation indicated by neutrophil-lymphocyte ratio (r = -0.211, P = 0.001). Univariate Cox regression analysis revealed hyperuricemia to not be associated with an increased risk of all-cause mortality in men with stable COPD (hazard ratio [HR], 0.580; 95% confidence interval [CI], 0.250-1.370; P = 0.213). In the multivariate Cox regression model, hyperuricemia was not an independent predictor of acute exacerbation (HR, 1.383; 95% CI, 0.977-1.959; P = 0.068). CONCLUSION Among men with stable COPD, hyperuricemia is not an independent predictor of all-cause mortality or future acute exacerbation of COPD. These results differ from those of previous studies on patients with acute exacerbation of COPD. © 2020 The Korean Academy of Medical Sciences.BACKGROUND Lack of sunlight exposure is the primary reason for the worldwide epidemic of vitamin D deficiency. Although recommended sunlight exposure guidelines exist, there is no evidence regarding whether current guidelines are optimal for increasing vitamin D levels among individuals with vitamin D deficiency. METHODS Sixty Korean adults aged 20-49 years with serum 25-hydroxyvitamin D (25[OH]D) levels of less then 20 ng/mL were randomly assigned to three groups sunlight exposure (n = 20), vitamin D supplementation groups (n = 20), and daily living (n = 20) for 1 month. The sunlight exposure group had sunlight exposure on 20% to 30% of their body surface areas for 30-60 minutes per day, 3 times a week during the summer season. Vitamin D supplementation was prescribed with 800 IU/day of vitamin D. The serum levels of 25(OH)D were measured at baseline and at 1-month follow-up examinations. RESULTS The largest change in serum 25(OH)D was observed among the vitamin D supplementation group (+3.5 ng/mL, P less then 0.001). The sunlight exposure group showed a slight increase in serum 25(OH)D level, but the absolute increase was less than one-third that of the vitamin D supplementation group (+0.9 ng/mL, P = 0.043). Only two participants in the sunlight exposure reached serum concentrations of 25(OH)D ≥ 20 ng/mL at follow-up. The daily living group showed no difference in vitamin D levels (-0.7 ng/mL, P = 0.516). CONCLUSION Sunlight exposure was not sufficient to overcome vitamin D insufficiency or deficiency in the current study subjects. Effectiveness of current sunlight exposure guidelines among various populations should be reassessed in larger clinical studies. TRIAL REGISTRATION Clinical Research Information Service Identifier KCT0002671. © 2020 The Korean Academy of Medical Sciences.BACKGROUND Pulmonary hypertension (PH) is common in patients with idiopathic pulmonary fibrosis (IPF) and is associated with poor outcomes. This study was performed to determine the clinical efficacy of PH-specific therapeutic agents for IPF patients. METHODS We performed a systematic review and meta-analysis using MEDLINE, EMBASE, and the Cochrane Central Register. We searched randomized controlled trials (RCTs) without language restriction until November 2018. The primary outcome was all-cause mortality to end of study. RESULTS We analyzed 10 RCTs involving 2,124 patients, 1,274 of whom received PH-specific agents.  https://www.selleckchem.com/products/cc-90011.html  In pooled estimates, the use of PH-specific agents was not significantly associated with reduced all-cause mortality to end of study compared with controls (hazard ratio, 0.99; 95% confidence interval [CI], 0.92, 1.06; P = 0.71; I² = 30%). When we performed subgroup analyses according to the type of PH-specific agent, sample size, age, forced vital capacity, diffusion lung capacity, and the extent of honeycombing, PH-specific agents also showed no significant association with a reduction in all-cause mortality. A small but significant improvement in quality of life, measured using the St. George Respiratory Questionnaire total score, was found in the PH-specific agent group (mean difference, -3.16 points; 95% CI, -5.34, -0.97; P = 0.005; I² = 0%). We found no significant changes from baseline in lung function, dyspnea, or exercise capacity. Serious adverse events were similar between the two groups. CONCLUSION Although PH-specific agents provided small health-related quality-of-life benefits, our meta-analysis provides insufficient evidence to support their use in IPF patients. © 2020 The Korean Academy of Medical Sciences.A bone stress injury (BSI) means that the bones cannot tolerate repeated mechanical loads, resulting in structural fatigue and local bone pain. A delay in BSI diagnosis can lead to more serious injuries, such as stress fractures that require longer treatment periods. Therefore, early detection of BSI is an essential part of management. Risk factors for BSI development include biological and biomechanical factors. Medical history and physical examination are the basics for a BSI diagnosis, and magnetic resonance imaging is helpful for confirming and grading. In this paper, the authors review the overall content of BSI and stress fractures which are common in runners. Through this review, we hope that interest in stress fractures will be raised in Korea and that active researches will be conducted. © 2020 The Korean Academy of Medical Sciences.