Stochastic Particle Flow for Nonlinear High-Dimensional Filtering Problems

A series of novel filters for probabilistic inference that propose an alternative way of performing Bayesian updates, called particle flow filters, have been attracting recent interest. These filters provide approximate solutions to nonlinear filtering problems. They do so by defining a continuum of densities between the prior probability density and the posterior, i.e. the filtering density. Building on these methods' successes, we propose a novel filter. The new filter aims to address the shortcomings of sequential Monte Carlo methods when applied to important nonlinear high-dimensional filtering problems. The novel filter uses equally weighted samples, each of which is associated with a local solution of the Fokker-Planck equation. This hybrid of Monte Carlo and local parametric approximation gives rise to a global approximation of the filtering density of interest. We show that, when compared with state-of-the-art methods, the Gaussian-mixture implementation of the new filtering technique, which we call Stochastic Particle Flow, has utility in the context of benchmark nonlinear high-dimensional filtering problems. In addition, we extend the original particle flow filters for tackling multi-target multi-sensor tracking problems to enable a comparison with the new filter

New Radiographic Index for Occipito-Cervical Instability

Study DesignRetrospective study.PurposeTo propose a new radiographic index for occipito-cervical instability.Overview of LiteratureSymptomatic atlanto-occipital instability requires the fusion of the atlanto-occipital joint. However, measurements of occipito-cervical translation using the Wiesel-Rothman technique, Power's ratio, and basion-axial interval are unreliable because the radiologic landmarks in the occipito-cervical junction lack clarity in radiography.MethodsOne hundred four asymptomatic subjects were evaluated with lateral cervical radiographs in neutral, flexion and extension. They were stratified by age and included 52 young (20–29 years) and 52 middle-aged adults (50–59 years). The four radiographic reference points were posterior edge of hard palate (hard palate), posteroinferior corner of the most posterior upper molar tooth (molar), posteroinferior corner of the C1 anterior ring (posterior C1), and posteroinferior corner of the C2 vertebral body (posterior C2). The distance from posterior C1 and posterior C2 to the above anatomical landmarks was measured to calculate the range of motion (ROM) on dynamic radiographs. To determine the difference between the two age groups, unpaired t-tests were used. The statistical significance level was set at p<0.05.ResultsThe ROM was 4.8±7.3 mm between the hard palate and the posterior C1, 9.9±10.2 mm between the hard palate and the posterior C2, 1.7±7.2 mm between the molar to the posterior C1, and 10.4±12.1 mm between the molar to the posterior C2. There was no statistically significant difference for the ROM between the young- and the middle-aged groups. The intra-observer reliability for new radiographic index was good. The inter-observer reliability for the ROM measured by the hard palate was low, but was better than that by the molar.ConclusionsROM measured by the hard palate might be a useful new radiographic index in cases of occipito-cervical instability

Impact of Physical Activity on All-Cause Mortality According to Specific Cardiovascular Disease

BackgroundPatients with cardiovascular disease (CVD) tend to have higher mortality rates and reduced physical activity (PA). We aimed to evaluate the effect of PA on mortality in older adults with specific CVD.MethodsWe enrolled 68,223 participants (n = 23,871 with CVD, n = 44,352 without CVD) aged ≥65 years with available physical activity data between 2005 and 2012 from the Korean National Health Insurance Service of Korea-Senior database. CVD was defined as a history of ischemic stroke, transient ischemic attack, heart failure, myocardial infarction, and peripheral artery disease.ResultsPatients with CVD were older than those without CVD. Compared with the sedentary group, the physically active groups with and without CVD had a lower incidence and risk of all-cause death during a median follow up period of 42 (interquartile range 30-51) months. A 500 metabolic equivalent task-min/week increase in PA resulted in an 11% and 16% reduction in the risk of mortality in the non-CVD and CVD groups, respectively. With regard to specific CVDs, the risk of mortality progressively reduced with increasing PA in patients with heart failure or myocardial infarction. However, the reduction reached a plateau in patients with stroke or peripheral artery disease, but was significantly greater in patients with stroke (20% vs. without stoke, 11%, Pint = 0.006) or heart failure (13% vs. without heart failure, 11%; Pint = 0.045).ConclusionsPA was associated with a reduced risk of all-cause mortality in older adults with and without CVD. The benefits of PA in patients with CVD, especially patients with stroke or heart failure, were greater than those without

Fasting Plasma Glucose Cutoff Value for the Prediction of Future Diabetes Development: A Study of Middle-Aged Koreans in a Health Promotion Center

We determined optimal fasting plasma glucose (FPG) cutoff values predictive of future diabetes development in a group of middle-aged Koreans who visited a health promotion center. The medical records of 2,964 subjects, who attended the Health Promotion Center in 1998 and 2003, were examined. Subjects were classified into four groups according to their baseline FPG values (Group 1:FPG <5.0 mM/L; Group 2: 5.0≤FPG <5.6 mM/L; Group 3: 5.6≤FPG <6.1 mM/L; Group 4: 6.1≤FPG <7.0 mM/L). No significant difference was observed between Group 1 and Group 2 in terms of diabetes incidence. However, incidence in Group 3 was significantly higher than that in Group 1 [hazards ratio 4.88 (1.65-14.41), p=0.004] and the hazards ratio in Group 4 for diabetes was 36.91 (13.11-103.61), p<0.001, versus Group 1. Receiver operator characteristics curve analysis showed that an FPG of 5.97 mM/L represents the lower limit and gives the best combination of sensitivity and specificity. Our data shows that the risk of future diabetes development started to increase below an FPG of 6.1 mM/L and suggests the importance of efforts to modify diabetes development risk factors at lower impaired fasting glucose levels

Increasing trends in hospital care burden of atrial fibrillation in Korea, 2006 through 2015

ObjectiveTemporal changes in the healthcare burden of atrial fibrillation (AF) are less well known in rapidly ageing Asian countries. We examined trends in hospitalisations, costs, treatment patterns and outcomes related to AF in Korea.MethodsUsing the National Health Insurance Service (NHIS) database involving the entire adult Korean population (n=41 701 269 in 2015), we analysed a nationwide AF cohort representing 931 138 patients with AF. We studied all hospitalisations due to AF from 2006 to 2015.ResultsOverall, hospitalisations for AF increased by 420% from 767 to 3986 per 1 million Korean population from 2006 to 2015. Most admissions occurred in patients aged ≥70 years, and the most frequent coexisting conditions were hypertension, heart failure and chronic obstructive pulmonary disease. Hospitalisations mainly due to major bleeding and AF control increased, whereas hospitalisations mainly due to ischaemic stroke and myocardial infarction decreased. The total cost of care increased even after adjustment for inflation from €68.4 million in 2006 to €388.4 million in 2015, equivalent to 0.78% of the Korean NHIS total expenditure. Overall in-hospital mortality decreased from 7.5% in 2006 to 4.3% in 2015. The in-hospital mortality was highest in patients ≥80 years of age (7.7%) and in patients with chronic kidney disease (7.4%).ConclusionsAF hospitalisations have increased exponentially over the past 10 years in Korea, in association with an increase in comorbid chronic diseases. Mortality associated with AF hospitalisations decreased during the last decade, but hospitalisation costs have markedly increased.</jats:sec

전립선 선암종에서 Methylenetetrahydrofolate Reductase 유전자형에 따른 CpG 섬 좌, LINE-1 및 Alu의 메틸화 양상 분석

Background : Genetic polymorphism of methylenetetrahydrofolate reductase (MTHFR), in association with the influence of MTHFR upon DNA methylation, may cause differences of the methylation profile of cancer. Thus, we investigated the relationship between the methylation status of prostate adenocarcinoma and the genetic polymorphism of MTHFR. Methods : We examined 179 cases of prostate adenocarcinoma for determining the genotypes of MTHFR 677 and 1298, the methylation status of 16 CpG island loci and the methylation levels of the LINE-1 and Alu repeats with using polymerase chain reaction/restriction fragment length polymorphism, methylation-specific polymerase chain reaction and combined bisulphite restriction analysis, respectively. Results : There was a higher proportion of the CT genotype of MTHFR 677 in the prostate adenocarcinoma than that in the normal control. The TT genotype of MTHFR 677 showed the highest frequency of methylation in six out of nine major CpG island loci, and these were which were frequently hypermethylated in prostate adenocarcinoma. The CT type showed the lowest methylation levels of LINE-1 and Alu among the MTHFR 677 genotypes. Interestingly, the CC type of MTHFR 1298 demonstrated favorable prognostic factors. Conclusions : Our study is the first to examine the methylation profile of prostate adenocarcinoma according to the MTHFR genotypes. The differences of the cancer risk, the genomic hypomethylation and the prognosis between the MTHFR genotypes in prostate adenocarcinoma should be further explored.Johansson M, 2007, CANCER CAUSE CONTROL, V18, P1169, DOI 10.1007/s10552-007-9055-zHubner RA, 2007, INT J CANCER, V120, P1027, DOI 10.1002/ijc.22440Cho NY, 2007, J PATHOL, V211, P269, DOI 10.1002/path.2106Pereira TV, 2006, CANCER EPIDEM BIOMAR, V15, P1956, DOI 10.1158/1055-9965.EPI-06-0334Larsson SC, 2006, GASTROENTEROLOGY, V131, P1271, DOI 10.1053/j.gastro.2006.08.010Cadieux B, 2006, CANCER RES, V66, P8469, DOI 10.1158/0008-5472.CAN-06-1547Graziano F, 2006, INT J CANCER, V118, P628, DOI 10.1002/ijc.21397Karpf AR, 2005, CANCER RES, V65, P8635, DOI 10.1158/0008-5472Kono S, 2005, CANCER SCI, V96, P535, DOI 10.1111/j.1349-7006.2005.00090.xLe Marchand L, 2005, CANCER EPIDEM BIOMAR, V14, P1198Friso S, 2005, CURR DRUG METAB, V6, P37Weisenberger DJ, 2005, NUCLEIC ACIDS RES, V33, P6823, DOI 10.1093/nar/gki987Chalitchagorn K, 2004, ONCOGENE, V23, P8841, DOI 10.1038/sj.onc.1208137Cicek MS, 2004, CANCER EPIDEM BIOMAR, V13, P1331Castro R, 2004, J MED GENET, V41, P454, DOI 10.1136/jmg.2003.017244Kim YI, 2004, CANCER EPIDEM BIOMAR, V13, P511Yang AS, 2004, NUCLEIC ACIDS RES, V32, DOI 10.1093/nar/gnh032Nelson WG, 2003, NEW ENGL J MED, V349, P366Gaudet F, 2003, SCIENCE, V300, P489Bariol C, 2003, AM J PATHOL, V162, P1361Shen HB, 2001, INT J CANCER, V95, P332, DOI 10.1002/1097-0215(20010920)95:53.0.CO2-9Kimura F, 2000, PROSTATE, V45, P225Weisberg I, 1998, MOL GENET METAB, V64, P169Esteller M, 1997, CARCINOGENESIS, V18, P2307Blount BC, 1997, P NATL ACAD SCI USA, V94, P3290Ma J, 1997, CANCER RES, V57, P1098Chen J, 1996, CANCER RES, V56, P4862FROSST P, 1995, NAT GENET, V10, P111