Spatialization and Prediction of Seasonal NO2 Pollution Due to Climate Change in the Korean Capital Area through Land Use Regression Modeling.

Urbanization is causing an increase in air pollution leading to serious health issues. However, even though the necessity of its regulation is acknowledged, there are relatively few monitoring sites in the capital metropolitan city of the Republic of Korea. Furthermore, a significant relationship between air pollution and climate variables is expected, thus the prediction of air pollution under climate change should be carefully attended. This study aims to predict and spatialize present and future NO2 distribution by using existing monitoring sites to overcome deficiency in monitoring. Prediction was conducted through seasonal Land use regression modeling using variables correlated with NO2 concentration. Variables were selected through two correlation analyses and future pollution was predicted under HadGEM-AO RCP scenarios 4.5 and 8.5. Our results showed a relatively high NO2 concentration in winter in both present and future predictions, resulting from elevated use of fossil fuels in boilers, and also showed increments of NO2 pollution due to climate change. The results of this study could strengthen existing air pollution management strategies and mitigation measures for planning concerning future climate change, supporting proper management and control of air pollution.

Atomic Layer Etching Mechanism of MoS2 for Nanodevices.

Among the layered transition metal dichalcogenides (TMDs) that can form stable two-dimensional crystal structures, molybdenum disulfide (MoS2) has been intensively investigated because of its unique properties in various electronic and optoelectronic applications with different band gap energies from 1.29 to 1.9 eV as the number of layers decreases. To control the MoS2 layers, atomic layer etching (ALE) (which is a cyclic etching consisting of a radical-adsorption step such as Cl adsorption and a reacted-compound-desorption step via a low-energy Ar+-ion exposure) can be a highly effective technique to avoid inducing damage and contamination that occur during the reactive steps. Whereas graphene is composed of one-atom-thick layers, MoS2 is composed of three-atom-thick S(top)-Mo(mid)-S(bottom) layers; therefore, the ALE mechanisms of the two structures are significantly different. In this study, for MoS2 ALE, the Cl radical is used as the adsorption species and a low-energy Ar+ ion is used as the desorption species. A MoS2 ALE mechanism (by which the S(top), Mo(mid), and S(bottom) atoms are sequentially removed from the MoS2 crystal structure due to the trapped Cl atoms between the S(top) layer and the Mo(mid) layer) is reported according to the results of an experiment and a simulation. In addition, the ALE technique shows that a monolayer MoS2 field effect transistor (FET) fabricated after one cycle of ALE is undamaged and exhibits electrical characteristics similar to those of a pristine monolayer MoS2 FET. This technique is also applicable to all layered TMD materials, such as tungsten disulfide (WS2), molybdenum diselenide (MoSe2), and tungsten diselenide (WSe2).

Effect of Recombinant Human Bone Morphogenetic Protein-2 and Adipose Tissue-Derived Stem Cell on New Bone Formation in High-Speed Distraction Osteogenesis.

PURPOSE: The effects of recombinant human bone morphogenetic protein-2 (rhBMP-2) and osteogenically differentiated adipose tissue-derived stem cells (ADSC) on new bone formation in high-speed distraction osteogenesis of adult rabbit cranium were investigated. MATERIALS AND METHODS: A total of 41 adult rabbits were used in the study. Distraction began after a 5-day latency period at a rate of 1.5 mm twice a day until 10-mm length gain was obtained both in the control group, where a bone defect was induced, and in the experimental group, in which ADSC (group A), rhBMP-2 (group B), or both (group C) were injected in the distraction gap after distraction. At 4, 8, and 12 weeks after distraction, computed tomography analysis was done to determine the bone defect dimension and bone mineral density (BMD), while histologic examination was also done to calculate bone formation ratio. RESULTS: Bone defect dimension significantly decreased in groups B and C, compared with the control group, at 4 and 12 weeks after distraction. BMD was significantly increased in groups B and C at 4 weeks. On histologic examination, bone formation ratio was significantly increased in group C only at 12 weeks. CONCLUSION: This study suggests that the use of rhBMP-2 in combination with or without ADSC is helpful to promote bone regeneration in high-speed distraction osteogenesi s of adult rabbit cranium.

Development of an activated carbon filter to remove NO2 and HONO in indoor air.

To obtain the optimum removal efficiency of NO2 and HONO by coated activated carbon (ACs), the influencing factors, including the loading rate, metal and non-metal precursors, and mixture ratios, were investigated. The NOx removal efficiency (RE) for K, with the same loading (1.0 wt.%), was generally higher than for those loaded with Cu or Mn. The RE of NO2 was also higher when KOH was used as the K precursor, compared to other K precursors (KI, KNO3, and KMnO4). In addition, the REs by the ACs loaded with K were approximately 38-55% higher than those by uncoated ACs. Overall, the REs (above 95%) of HONO and NOx with 3% KOH were the highest of the coated AC filters that were tested. Additionally, the REs of NOx and HONO using a mixing ratio of 6 (2.5% PABA (p-aminobenzoic acid)+6% H3PO4):4 (3% KOH) were the highest of all the coatings tested (both metal and non-metal). The results of this study show that AC loaded with various coatings has the potential to effectively reduce NO2 and HONO levels in indoor air.

Lipoprotein-associated phospholipase A2 is related to plaque stability and is a potential biomarker for acute coronary syndrome.

PURPOSE: Plasma lipoprotein-associated phospholipase A2 (Lp-PLA2) binds to low-density lipoprotein. The levels of Lp-PLA2 reflect the plaque burden, and are upregulated in acute coronary syndrome (ACS). We investigated the diagnostic value of Lp-PLA2 levels and found that it might be a potential biomarker for ACS. MATERIALS AND METHODS: We classified 226 study participants into three groups: patients without significant stenosis (control group), patients with significant stenosis with stable angina (SA group), and patients with ACS (ACS group). RESULTS: Lp-PLA2 and high-sensitivity C-reactive protein (hs-CRP) levels were significantly greater in the ACS group than in the SA group (p=0.044 and p=0.029, respectively). Multivariate logistic regression analysis revealed that Lp-PLA2 levels are significantly associated with ACS (odds ratio=1.047, p=0.013). The addition of Lp-PLA2 to the ACS model significantly increased the global χ² value over traditional risk factors (28.14 to 35.602, p=0.006). The area under the receiver operating characteristic curve for Lp-PLA2 was 0.624 (p=0.004). The addition of Lp-PLA2 level to serum hs-CRP concentration yielded an integrated discrimination improvement of 0.0368 (p=0.0093, standard error: 0.0142) and improved the ability to diagnose ACS. CONCLUSION: Lp-PLA2 levels are related to plaque stability and might be a diagnostic biomarker for ACS.

Spontaneous coronary artery dissection mimicking coronary spasm diagnosed by intravascular ultrasonography.

Spontaneous coronary artery dissection (SCAD) is a rare and occasionally life-threatening cause of acute coronary syndrome. Patients may present with clinical scenarios ranging from angina pectoris to cardiogenic shock to sudden cardiac death, and it may be a potentially life-threatening condition if not recognized. However, its etiology, pathophysiology and optimal therapeutic strategies have not been well understood. SCAD is diagnosed on the basis of coronary angiography, but complementary techniques as such intravascular ultrasound (IVUS) and optical coherence tomography should be considered for diagnostic clarification where appropriate. Likewise, the selection of treatment strategy depends upon the clinical manifestation, location and the extent of dissection and amount of ischemic myocardium at risk. Herein, we present the case of a 35-year-old woman who presented with acute myocardial infarction. She was diagnosed by IVUS with spontaneous diffuse dissection of the left anterior descending artery without atheroma, treated with percutaneous coronary stenting, and had a favorable clinical course and was discharged on medical therapy.

Prognostic significance of elevated lipoprotein(a) in coronary artery revascularization patients.

BACKGROUND: Although lipoprotein(a) [Lp(a)] has been considered a cardiovascular risk factor for many years, there is a paucity of data in regard to the potential risk of elevated Lp(a) in symptomatic patients with CAD. Therefore, we sought to evaluate whether elevated Lp(a) is associated with worse outcome in symptomatic patients with coronary artery disease (CAD), and to clarify the prognostic value of Lp(a) in the era of coronary artery revascularization. METHODS: 6252 consecutive subjects (59.2% male, mean age 61.2 ± 11.2 years) suspected of having CAD underwent coronary angiography. Laboratory values for lipid parameters including Lp(a) were obtained on the day of coronary angiography. Baseline risk factors, coronary angiographic findings, length of follow-up, and major adverse cardiovascular events (MACE), including cardiac death and non-fatal myocardial infarction were recorded. RESULTS: Over a mean follow-up period of 3.1 ± 2.2 years, there were 100 MACE (56 cardiac deaths and 44 non-fatal myocardial infarctions), with an event rate of 1.6%. In multivariate Cox regression analysis, elevated Lp(a) was a significant predictor of MACE [hazard ratio 1.773 (95% confidence interval 1.194-2.634, p=0.005)], and the addition of this factor to the model significantly increased the global х(2) value over traditional risk factors and CAD (from 79.1 to 88.7, p=0.003). CONCLUSIONS: Elevated Lp(a) is an independent prognostic risk factor for cardiovascular events, and moreover, has incremental prognostic value in symptomatic patients with coronary artery revascularization.

Diverse left ventricular morphology and predictors of short-term outcome in patients with stress-induced cardiomyopathy.

BACKGROUND: There is paucity of data with regard to the clinical spectrum according to left ventricle (LV) morphological variation in stress-induced cardiomyopathy (SCMP) patients, and still there is controversy in terms of prognosis since some people believe that the published in-hospital mortality data of patients with SCMP are underestimated. Therefore, we sought to investigate the morphological features of LV and in-hospital outcome of patients with SCMP and explored predictors of short-term prognosis. METHODS: This was a multicenter, observational study of 208 SCMP patients. Morphological features of LV were determined by echocardiography and were divided into typical (apical) and atypical ballooning types, which were subcategorized into mid-LV ballooning and basal 'inverted' ballooning type. All-cause mortality of patients with SCMP during hospitalization was recorded. RESULTS: The apical ballooning type was most common (67.3%) in SCMP followed by the mid-LV ballooning type (28.3%), and the basal 'inverted' ballooning type (4.3%). There were no differences in stressor types and in-hospital mortality between patients with typical and atypical SCMP. Notably, all the in-hospital mortality of SCMP patients occurred in patients with physical stressors, where age, shock, and LV ejection fraction were the independent risk factors for predicting in-hospital mortality. CONCLUSIONS: SCMP patients showed diverse patterns of LV morphology, but there were no definite differences on clinical spectrum among SCMP patients presenting various LV morphological patterns. In terms of short-term prognosis, underlying physical conditions combined with old age, hemodynamic compromise, and low LV systolic function might be the most important factors in SCMP patients.

Beneficiation of coal pond ash by physical separation techniques.

In this study, investigations to develop a beneficiation process for separating coal pond ash into various products were undertaken. To this end, coal pond ash samples with different particle size ranges were tested in terms of their washability characteristics in a float-and-sink analysis. It was found that coal pond ash was heterogeneous in nature consisting of particles that varied in terms of their size and composition. However, it can be made more homogenous using a gravity separation method. Therefore, the possibility of separating coal pond ash was tested on standard equipment typically used for gravity concentration. To increase the separation efficiency, coal ash was separated according to the size of the particles and each size fraction was tested using equipment appropriate for the corresponding sizes. A hindered-settling column and a shaking table were tested for their ability to treat the 1.19 × 0.074 mm size fraction, and a Falcon concentrator was evaluated for its ability to treat the -0.074 mm size fraction. The results showed that various marketable products, such as lightweight aggregate, sand and high-carbon fuel, can be recovered from coal pond ash using simple physical separation techniques.

Evaluation of neointimal morphology of lesions with or without in-stent restenosis: an optical coherence tomography study.

BACKGROUND: Characterization of neointimal tissue is essential to understand the pathophysiology of in-stent restenosis (ISR) after drug-eluting stent (DES) implantation. Using optical coherence tomography (OCT), we compared the morphologic characteristics of in-stent neointimal tissue from 33 ISR lesions with those of 192 non-ISR lesions after DES implantation. HYPOTHESIS: We hypothesized that the morphologic characteristics of in-stent neointimal tissue from ISR lesions were different from those of non-ISR lesions after DES implantation. METHODS: The DES were coated with sirolimus (n=52), paclitaxel (n=57), zotarolimus (n=84), or everolimus (n=32). In-stent restenosis was defined as ≥50% diameter stenosis at the follow-up angiogram. Lesions with ≥10% neointimal burden ([neointima area × 100]/[stent area]), as determined by OCT, were included in this study. A follow-up OCT (mean follow-up duration, 12.0 ± 10.5 mo) was performed in 209 patients with 225 lesions (ISR lesions, n=33; non-ISR lesions, n=192). Qualitative OCT was used to assess tissue structure, backscatter, visible microvessels, and presence of intraluminal material. RESULTS: The following characteristics were more common in ISR lesions than in non-ISR lesions: heterogeneous or layered tissues (78.8% vs 22.9%, P<0.001), low backscatter (60.6% vs 20.8%, P<0.001), and microvessels (48.5% vs 5.7%, P<0.001). The independent predictors for heterogeneous or layered neointimal tissues were increased neointima burden (odds ratio [OR]: 1.218, 95% confidence interval [CI]: 1.096-1.354, P<0.001), lumen area (OR: 4.672, 95% CI: 1.371-15.914, P = 0.014), and hypertension (OR: 0.415, 95% CI: 0.186-0.926, P = 0.032). CONCLUSIONS: This follow-up OCT study demonstrated that morphologic characteristics of neointimal tissues of ISR lesions differ from those of non-ISR lesions.

Predictors of stent fracture in patients treated with closed-cell design stents: sirolimus-eluting stent and its bare-metal counterpart, the BX velocity stent.

OBJECTIVE: The aim of this study was to evaluate the predictors of coronary stent fracture in patients treated with closed-cell design stents including the sirolimus-eluting stent (SES) and its bare-metal platform, Bx velocity stent (BVS). BACKGROUND: Various mechanical factors have been considered to be the predictors of stent fracture, especially in patients treated with SES. However, it is unknown whether SES is more prone to fracture compared with BVS. METHODS: We retrospectively analyzed 391 lesions treated with SES or BVS in 339 patients who underwent follow-up coronary angiography. RESULTS: A total of 30 stent fractures (7.7%) in 28 patients treated with 29 SES (96.7%) and one BVS (3.3%) was found. On univariate analyses, stent fracture was related to angulated lesions (>45°) during diastole, longer stent, larger number of stents per lesion (P<0.001), right coronary artery (RCA) placement (P=0.008), and SES (P=0.016). On multivariate analyses, however, angulated lesion (odds ratio: 6.73; 95% confidence interval: 2.71-16.71; P<0.001) and RCA placement (odds ratio: 2.82; 95% confidence interval: 1.03-7.72; P=0.044) served as independent predictors of stent fracture while SES (P=0.080) and total stent length (P=0.069) showed only trends that did not reach statistical significance. CONCLUSIONS: This study showed that fracture of SES or BVS with the same closed-cell design platform was related to angulated lesion and RCA placement, but SES itself was not an independent predictor of stent fracture.

A new method for generating an invariant iris private key based on the fuzzy vault system.

Cryptographic systems have been widely used in many information security applications. One main challenge that these systems have faced has been how to protect private keys from attackers. Recently, biometric cryptosystems have been introduced as a reliable way of concealing private keys by using biometric data. A fuzzy vault refers to a biometric cryptosystem that can be used to effectively protect private keys and to release them only when legitimate users enter their biometric data. In biometric systems, a critical problem is storing biometric templates in a database. However, fuzzy vault systems do not need to directly store these templates since they are combined with private keys by using cryptography. Previous fuzzy vault systems were designed by using fingerprint, face, and so on. However, there has been no attempt to implement a fuzzy vault system that used an iris. In biometric applications, it is widely known that an iris can discriminate between persons better than other biometric modalities. In this paper, we propose a reliable fuzzy vault system based on local iris features. We extracted multiple iris features from multiple local regions in a given iris image, and the exact values of the unordered set were then produced using the clustering method. To align the iris templates with the new input iris data, a shift-matching technique was applied. Experimental results showed that 128-bit private keys were securely and robustly generated by using any given iris data without requiring prealignment.

Low T cell receptor expression and thermal fluctuations contribute to formation of dynamic multifocal synapses in thymocytes.

Mature T cell activation and selection of immature T cells (thymocytes) are both initiated by binding of T cell receptor (TCR) molecules on the surface of T cells to MHC peptide (MHCp) molecules on the surface of antigen-presenting cells. Recent experiments have shown that the spatial pattern of receptors and ligands in the intercellular junction (synapse) is different during thymocyte selection compared with mature T cell activation. Using a statistical mechanical model, we show that lower TCR expression in thymocytes contributes to effecting these differences. An analogy with the phase behavior of simple fluids helps clarify how, for low TCR expression, thermal fluctuations lead to the dynamic synapse patterns observed for thymocytes. We suggest that a different synapse pattern resulting from lower TCR expression, which could mediate differential signaling, may be the reason why TCR expression level is low in thymocytes.

Correlation of a dynamic model for immunological synapse formation with effector functions: two pathways to synapse formation.

During antigen recognition by T cells different receptors and ligands form a pattern in the intercellular junction called the immunological synapse, which might be involved in T-cell activation. Recently, a synapse assembly model has been proposed, which enables the calculation of the propensity for synapse assembly driven by membrane-constrained protein binding interactions. We bring together model predictions of mature synapse assembly with data on the dependence of T-cell responses on T-cell receptor (TCR)-MHC-peptide (pMHC) binding kinetics. Predictions of mature synapse assembly, based on TCR-pMHC binding kinetics, correlate well with observed cytokine responses by T cells bearing the relevant TCR but not with cytotoxic T lymphocyte-mediated killing. We discuss the suggested different role for the synapse in pre- and post-nuclear activation events in T cells. The view of immunological synapse assembly given here emphasizes the importance of both the on and off rates for the TCR-pMHC interaction and in this context recent data on a positive role for analogs of self-peptides in synapse assembly is considered.

The synapse assembly model.

A framework for quantitative analysis of the mechanisms underlying immunological synapse assembly has been recently developed. This model uses partial differential equations to describe the binding interactions of receptors and ligands, with the constraint that they are embedded in apposed deformable membranes linked to a cytoskeletal complex.