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Harmonic Pulse Testing (HPT) has been developed as a type of well testing applicable during ongoing field operations because a pulsed signal is superimposed on background pressure trend. Its purpose is to determine well and formation parameters such as wellbore storage, skin, permeability, and boundaries within the investigated volume. Compared to conventional well testing, HPT requires more time to investigate the same reservoir volume. The advantage is that it does not require the interruption of well and reservoir injection/production before and/or during the test because it allows the extraction of an interpretable periodic signal from measured pressure potentially affected by interference. This makes it an ideal monitoring tool. Interpretation is streamlined through diagnostic plots mimicking conventional well test interpretation methods. To this end, analytical solutions in the frequency domain are available. The methodology was applied to monitor stimulation operations performed at an Enhanced Geothermal System site in Pohang, Korea. The activities were divided into two steps: first, a preliminary sequence of tests, injection/fall‐off, and two HPTs, characterized by low injection rates and dedicated to estimate permeability prior to stimulation operations, and then stimulation sequence characterized by a higher injection rate. During the stimulation operations other HPT were performed to monitor formation properties behavior. The interpretation of HPT data through the derivative approach implemented in the frequency domain provided reliable results in agreement with the injection test. Moreover, it provided an estimation of hydraulic properties without cessation of stimulation operations, thus confirming the effectiveness of HPT application for monitoring purposes. Key Points: An advanced methodology for well performance monitoring without production interruption is presentedDiagnostic plots analogous to oil industry conventional well testing for flow geometry and regime identification were adoptedA field case validation shows the successful application of the methodology to monitor the stimulation of a well of an enhanced geothermal system [ABSTRACT FROM AUTHOR]

What is known and objective There are a few Korean studies on the economics of statins based on reduction in low-density lipoprotein cholesterol ( LDL-C) data from other countries. This study aimed to analyse and compare the cost-effectiveness of statins according to the baseline LDL-C level in Korea. Methods Between January 2009 and December 2015, the data of patients who were prescribed statins for the first time were extracted from electronic medical records. We performed a cost-effectiveness analysis ( CEA) based on the LDL-C reduction rate ( CEA- RR) and target achievement rate. Results and discussion Among high-intensity statins, the CEA- RR value of rosuvastatin (20 mg) was significantly lower than that of atorvastatin (40 mg) at all baseline LDL-C levels, except levels of 160-189 mg/ dL. Additionally, at baseline LDL-C levels of 130-159 mg/ dL, the CEA- RR value of rosuvastatin (20 mg) was three times lower than that of atorvastatin (40 mg) (9·1 ± 2·5 $/% vs. 31·7 ± 15·0 $/%, P < 0·001). Among moderate-to-low-intensity statins, rosuvastatin (5 mg) showed the lowest CEA- RR value (4·0 ± 0·6 $/%), and the value significantly increased for pitavastatin (2 mg) (8·0 ± 0·6 $/%), atorvastatin (10 mg) (9·5 ± 0·5 $/%), simvastatin (10·8 ± 1·1 $/%) and pravastatin (40 mg) (11·5 ± 0·9 $/%) in order ( P < 0·0001). On changing from atorvastatin (10 mg) to atorvastatin (20 mg), the additional yearly cost was 16·0 and additional CEA- RR value was 2·74 $/%. On the other hand, on changing from atorvastatin (10 mg) to rosuvastatin (10 mg), the additional yearly cost was −16·3 and additional CEA- RR value was −1·8 $ /%. What is new and conclusion We successfully compared the cost-effectiveness of statins according to the baseline LDL-C level in Korea. It is expected that our findings will help clinical decision-making with regard to statin prescription, and this will help reduce national medical expenditure. [ABSTRACT FROM AUTHOR]

Summary: Because the rate of bone loss is an important risk factor for fracture, we studied longitudinal changes in bone mineral density (BMD). Although the BMD of the hip decreased over time, spine BMD remained largely stable or increased. Therefore, spine BMD may not be appropriate for assessing BMD change. Introduction: The rate of age-dependent bone loss has been shown to be an important risk factor for fracture. However, longitudinal rates of BMD loss in Korea have not yet been reported. The objective of this study was to evaluate longitudinal changes in BMD in Korea. Methods: This cohort study was performed in a population of individuals 40 years of age or older living in the rural area of Chungju City, Korea. A second BMD examination was conducted approximately 4 years after a baseline examination. A total of 3755 of the 6007 subjects completed the follow-up visit, corresponding to a follow-up rate of 62.51%. Results: The age-standardized osteoporosis prevalence was 12.81% in males and 44.35% in females. In males, the average annual BMD loss at the total hip increased from −0.25% per year in their 40s to −1.12% per year in their 80s. In females, the average annual BMD loss at the total hip increased from −0.69% per year in their 40s to −1.51% per year in their 80s. However, the average annual percentage change in spine BMD in females increased from −0.91% per year in their 40s to +1.39% per year in their 80s. Conclusions: A substantial number of subjects had osteoporosis, even though we standardized the prevalence of osteoporosis. In total hip, the mean BMD was decreased during the follow-up period; in addition, the annual percentage loss increased with age. However, spine BMD remained approximately stable or increased over time and therefore may not be appropriate for assessing BMD change. [ABSTRACT FROM AUTHOR]

What is known and objective There is a disparity between the Korean treatment guidelines and actual clinical prescription habits. This study was designed to evaluate the department-specific disparities and achievement rates for low-density lipoprotein cholesterol ( LDL-C) targets, based on each department's specific statin prescription patterns. Methods We retrospectively evaluated data from 31 718 patients who had been prescribed a statin at least once between January 2008 and June 2013 at our institution. Patients were classified into the high-risk (target LDL-C < 100 mg/ dL) or moderate-risk (target LDL-C < 130 mg/ dL) groups, according to the National Cholesterol Education Programme-Adult Treatment Panel III guidelines. Results and discussion Statins were most commonly prescribed in the cardiology (32·0%) and endocrinology (26·6%) departments. For the high-risk group, 70% of patients in the cardiology, endocrinology and cardiac surgery departments achieved their target LDL-C levels (<100 mg/ dL). However, the target achievement rates in most other departments were <70%. For the moderate-risk group, 79·2% of patients achieved their target levels. Departments that prescribed a greater number of high- or intermediate-potency statins were more likely to achieve their target LDL-C levels. The group that achieved their target LDL-C levels (<100 mg/ dL) exhibited a significant positive relationship (Spearman's correlation coefficient = 0·8571, P = 0·0065), from low to high potency. What is new and conclusion Some departments tend to undertreat when prescribing statins. However, to reach to the target LDL-C levels, physicians must overcome their tendency to undertreat with statins. We believe that the target achievement rate will increase if doctors are more actively aware of a patient's individual status and related risk factors before prescribing statins. [ABSTRACT FROM AUTHOR]

Proper maintenance of fighter aircraft is an important issue to control the airpower. Typical maintenance policy applied is based on the constant schedule for a given module. This kind of maintenance does not take into account varying characteristics of the module over time. In this paper, we utilize the random effects Weibull regression model for non-constant MTBF (mean time between failure) and MTTR (mean time to repair) in order to provide a dynamic preventive maintenance schedule reflecting the module's varying characteristics in a timely manner. Our study is expected to contribute to ROKA (Republic of Korea Airforce) in terms of improving the level of combat readiness of fighter aircraft. [ABSTRACT FROM AUTHOR]

Aims Patient education is a very important part of diabetes care. However, until now, little data has been presented about the long-term effectiveness of structured intensive diabetes education programmes (SIDEP) for people with Type 2 diabetes mellitus. Methods People with Type 2 diabetes ( n = 547) hospitalized from December 1999 to December 2000 were randomly assigned to two groups. Two hundred and nineteen patients undertook an inpatient SIDEP and the remaining patients received conventional glycaemic control without intensive education. After discharge, all patients were monitored regularly. Laboratory data were obtained, and adherence to self-care behaviour was determined on a five-point scale by questionnaires completed annually. Results Of the patients who completed the SIDEP, 160 (73.1%) were followed up for more than 4 years. The mean HbA1c (7.9 ± 1.2 vs. 8.7 ± 1.6%; P < 0.05) and the frequency of hospitalization related to diabetes per patient per year (0.3 ± 0.6 vs. 0.8 ± 0.9; P < 0.05) was significantly lower in the SIDEP group than in the control group. The SIDEP group adhered more closely to self-care behaviour than the control group over 4 years ( P < 0.05). People with Type 2 diabetes mellitus of longer duration and those treated with insulin had poorer HbA1c at follow-up. Conclusions A well-designed, intensive patient education programme is necessary for people with diabetes. However, regular and sustained reinforcement with encouragement is also required to maintain optimal glycaemic control, especially in insulin-treated patients. [ABSTRACT FROM AUTHOR]

Circulating tumor DNA (ctDNA) has been known to be released from tumor cells and evaluated as potential biomarkers for therapeutic responses. In our previous study, we proved applicability for KRAS mutation as a prognostic marker in pancreatic ductal adenocarcinoma (PDA) through the quantitative analysis of ctDNA using KRAS multiplex kit which covers 7 sites. In this study, we analyzed distribution of each single mutation in tumor and ctDNA by performed droplet digital PCR (ddPCR). Total of 126 PDA patients were enrolled and analyzed for tumor DNA. We found 94 patients have samples for matched ctDNA analysis. Plasma was separated by established method and ctDNA were extracted using QIAamp Circulating Nucleic Acid Kit. QX200 Droplet Digital PCR System was applied to measure frequency of KRAS mutations using KRAS screening multiplex kit and probe for G12D, G12V and G12C in ctDNA and tumor DNA. Then, we compared the frequency between multiplex and single point mutation of KRAS. The positivity of mutation of tumor and ctDNA in multiplex ddPCR were 96.0% (n = 121/126) and 60.3% (n = 76/126), respectively. Positive rates of G12D, G12V and G12C were 59.6%, 24.5% and 22.3% in tumor and 36.2%, 16.0% and 17.0% in ctDNA, respectively. There was a correlation between multiplex and the sum of single point mutation (r = 0.805). In the single point mutation results, 44 of the samples detected in both tumor and ctDNA mutations were detected in the same site (75.9%), 12 of them were partially identical (19.0%), and 3 were inconsistent (5.2%). Comparing the frequency with other studies, G12D and G12V showed no difference in frequency, but G12C showed a higher positive rate than the previous studies even though we did not analysis for G12R. Multiple KRAS mutations were found in 17% and 6.4% in tumor and ctDNA. These results show that the frequency of KRAS mutation correlated with tumor tissue and ctDNA. Also multiple mutations were detected high proportion compared to the previous studies. Further studies are needed to determine G12R proportion. We further evaluate whether the single point mutation detected by single probe is more valuable than sum of mutations from KRAS multiplex kit as a biomarker for predicting the prognosis of PDA. Sun-Young Kong. National Cancer Center and the Ministry of Health & Welfare, Republic of Korea. All authors have declared no conflicts of interest. [ABSTRACT FROM AUTHOR]