Multi-point measurement using two-channel reflectometer with antenna switching for study of high-frequency fluctuations in GAMMA 10

A two-channel microwave reflectometer system with fast microwave antenna switching capability was developed and applied to the GAMMA 10 tandem mirror device to study high-frequency small-amplitude fluctuations in a hot mirror plasma. The fast switching of the antennas is controlled using PIN diode switches, which offers the significant advantage of reducing the number of high-cost microwave components and digitizers with high bandwidths and large memory that are required to measure the spatiotemporal behavior of the high-frequency fluctuations. The use of two channels rather than one adds the important function of a simultaneous two-point measurement in either the radial direction or the direction of the antenna array to measure the phase profile of the fluctuations along with the normal amplitude profile. The density fluctuations measured using this system clearly showed the high-frequency coherent fluctuations that are associated with Alfvén-ion-cyclotron (AIC) waves in GAMMA 10. A correlation analysis applied to simultaneously measured density fluctuations showed that the phase component that was included in a reflected microwave provided both high coherence and a clear phase difference for the AIC waves, while the amplitude component showed neither significant coherence nor clear phase difference. The axial phase differences of the AIC waves measured inside the hot plasma confirmed the formation of a standing wave structure. The axial variation of the radial profiles was evaluated and a clear difference was found among the AIC waves for the first time, which would be a key to clarify the unknown boundary conditions of the AIC waves.

Future climate change impact assessment of watershed scale hydrologic processes in Peninsular Malaysia by a regional climate model coupled with a physically-based hydrology modelo

Impacts of climate change on the hydrologic processes under future climate change conditions were assessed over Muda and Dungun watersheds of Peninsular Malaysia by means of a coupled regional climate and physically-based hydrology model utilizing an ensemble of future climate change projections. An ensemble of 15 different future climate realizations from coarse resolution global climate models' (GCMs) projections for the 21st century was dynamically downscaled to 6km resolution over Peninsular Malaysia by a regional climate model, which was then coupled with the watershed hydrology model WEHY through the atmospheric boundary layer over Muda and Dungun watersheds. Hydrologic simulations were carried out at hourly increments and at hillslope-scale in order to assess the impacts of climate change on the water balances and flooding conditions in the 21st century. The coupled regional climate and hydrology model was simulated for a duration of 90years for each of the 15 realizations. It is demonstrated that the increase in mean monthly flows due to the impact of expected climate change during 2040-2100 is statistically significant from April to May and from July to October at Muda watershed. Also, the increase in mean monthly flows is shown to be significant in November during 2030-2070 and from November to December during 2070-2100 at Dungun watershed. In other words, the impact of the expected climate change will be significant during the northeast and southwest monsoon seasons at Muda watershed and during the northeast monsoon season at Dungun watershed. Furthermore, the flood frequency analyses for both watersheds indicated an overall increasing trend in the second half of the 21st century.

Risk of fractures and diabetes medications: a nationwide cohort study

The effects of diabetes medications on risk of fracture were investigated using the South Korea nationwide claims database. We demonstrated that the use of dipeptidyl peptidase-4 inhibitor could be associated with decreased risk of fracture. Thiazolidinedione use was associated with about 60 % increased risk of fracture in real clinical practice.

INTRODUCTION

The effects of diabetes medication on fracture have important clinical health consequences, since most diabetes patients are at high risk of fracture. We aimed to investigate the effect of diabetes medication on fracture risk.

METHODS

The nationwide medical claim database in South Korea was investigated. Among 2,886,555 subjects with antidiabetes prescriptions, 207,558 subjects aged 50 years and older, who initiated diabetes medication from 2008 to 2011, were analyzed. The subjects were classified based on diabetes medication classes: non-user (insufficient exposure), metformin (MET), sulfonylurea (SU), alpha-glucosidase inhibitor (AGI), MET + SU, MET + thiazolidinedione (TZD), MET + dipeptidyl peptidase-4 inhibitor (DPP4-I), and SU + TZD.

RESULTS

A total of 5996 fractures were observed. The fracture rate varied significantly across type of diabetes medications, with MET + DPP4-I combination group having the lowest rate and SU + TZD combination group having the highest rate. Compared to non-users, MET + DPP4-I inhibitor combination group had significantly reduced composite fracture risk (hazard ratio (HR) = 0.83, P = 0.025) and significantly reduced vertebral fracture risk (HR = 0.73, P = 0.013) in the unadjusted analysis. Compared to MET + SU users, MET + DPP4-I users showed a trend of lower non-vertebral fracture risk (HR = 0.82, P = 0.086) after adjusting for all confounding variables. Patients using TZD had significantly increased risk of fracture (HR = 1.59, P < 0.001) compared with patients not using TZDs adjusting for all confounding variables.

CONCLUSIONS

The results of this nationwide study showed a trend that DPP4 inhibitor might have a protective effect on bone metabolism compared with SU, when added to MET. Clinicians should take these results into consideration when prescribing diabetes medication, especially in elderly patients or those at high risk or fracture.

Current trends and future projections of hip fracture in South Korea using nationwide claims data

Incidence of hip fracture increased in Korean populations over age 50 between 2008 and 2012, and the number of fractures was predicted to increase by 1.4 times by 2025. This is important information for public health planning.

INTRODUCTION

The purposes of this study were to evaluate the trends in the incidence and mortality of hip fracture between 2008 and 2012 and predict the number of hip fractures in Korea through 2025 using nationwide claims data.

METHODS

The data managed by the National Health Insurance Service were used to identify the hip fractures in patients aged >50 years between 2008 and 2012. Projections of hip fractures were conducted using the Poisson distribution from 2016 to 2025 in Korea.

RESULTS

The incidence of hip fractures (per 100,000) increased by 14.1 % over the 5 years of the study, by 15.8 % in women and 10.9 % in men; the older age group showed a steep rise and shift in the incidence from 2008 to 2012. The cumulative mortality rates at 1 year after hip fractures were 17.2 % (3575/20,849) in 2008 and 16.0 % (4547/28,426) in 2012. Overall standardized mortality ratios (SMRs) for hip fracture were higher in men (11.93) than in women (11.22) and were higher than those in the general population in all age groups. In 2016, the total number of hip fractures was estimated to increase an overall of 1.4 times by 2025.

CONCLUSIONS

The incidence of hip fracture continues to increase, and the related mortality is still high, although it has decreased over time. The socioeconomic burden of hip fracture is expected to increase in Korea along with the increased estimated number of fractures. Nationwide strategies should include attempts to reduce the future socioeconomic burdens of hip fractures.

Safety and efficacy of endoscopic spray cryotherapy for Barrett's dysplasia: results of the National Cryospray Registry

Retrospective series have shown the efficacy of endoscopic spray cryotherapy in eradicating high-grade dysplasia (HGD) in Barrett's esophagus (BE); however, prospective data are lacking, and efficacy for low-grade dysplasia (LGD) is unclear. The aim of this study was to assess the efficacy and safety of spray cryotherapy in patients with LGD or HGD. A multicenter, prospective open-label registry enrolled patients with dysplastic BE. Spray cryotherapy was performed every 2-3 months until there was no endoscopic evidence of BE and no histological evidence of dysplasia, followed by surveillance endoscopies up to 2 years. Primary outcome measures were complete eradication of dysplasia (CE-D) and complete eradication of all intestinal metaplasia (CE-IM). Ninety-six subjects with Barrett's dysplasia (67% HGD; 65% long-segment BE; mean length 4.5 cm) underwent 321 treatments (mean 3.3 per subject). Mean age was 67 years, 83% were male. Eighty patients (83%) completed treatment with follow-up endoscopy (mean duration 21 months). In patients with LGD, rate of CE-D was 91% (21/23) and rate of CE-IM was 61% (14/23). In HGD, CE-D rate was 81% (46/57) and CE-IM was 65% (37/57). In patients with short-segment BE (SSBE) with any dysplasia, CE-D was achieved in 97% (30/31) and CE-IM in 77% (24/31). There were no esophageal perforations or related deaths. One subject developed a stricture, which did not require dilation. One patient was hospitalized for bleeding in the setting of non-steroidal anti-inflammatory drug use. In the largest prospective cohort to date, data suggest endoscopic spray cryotherapy is a safe and effective modality for eradication of BE with LGD or HGD, particularly with SSBE.

Ashkin-Teller model and diverse opinion phase transitions on multiplex networks

Multiplex networks (MNs) have become a platform of recent research in network sciences because networks in many real-world systems interact and function together. One of the main scientific issues in MNs is how the interdependence changes the emerging patterns or phase transitions. Until now, studies of such an issue have concentrated on cluster-breakdown phenomena, aiming to understand the resilience of the system under random failures of edges. These studies have revealed that various phase transition (PT) types emerge in MNs. However, such studies are rather limited to percolation-related problems, i.e., the limit q→1 of the q-state Potts model. Thus, a systematic study of opinion formation in social networks with the effect of interdependence between different social communities, which may be seen as the study of the emerging pattern of the Ising model on MNs, is needed. Here we study a well-known spin model called the Ashkin-Teller (AT) model in scale-free networks. The AT model can be regarded as a model for interacting systems between two species of Ising spins placed on respective layers in double-layer networks. Our study shows that, depending on the interlayer coupling strength and a network topology, unconventional PT patterns can also emerge in interaction-based phenomena: continuous, discontinuous, successive, and mixed-order PTs and a continuous PT not satisfying the scaling relation. The origins of such rich PT patterns are elucidated in the framework of Landau-Ginzburg theory.