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Reverse K-Nearest Neighbor (RKNN) queries in road networks have been studied extensively in recent years. However, at present, there is still a lack of algorithms for moving queries in a road network. In this paper, we study how to efficiently process moving queries. Existing algorithms do not efficiently handle query movement. For instance, whenever a query changes its location, the result of the query has to be recomputed. To avoid this recomputation, we introduce a new technique that can efficiently compute the safe exit points for continuous RKNNs. Within these safe exit points, the query result remains unchanged and a request for recomputation of the query does not have to be made to the server. This significantly reduces server processing costs and the communication costs between the server and moving clients. The results of extensive experiments conducted using real road network data indicate that our proposed algorithm significantly reduces communication and computation costs. [ABSTRACT FROM AUTHOR]

Purpose: Resistant hypertension (HTN) occurs in 15-20% of treated hypertensive patients, and 70-80% of resistant hypertensive patients have obstructive sleep apnea (OSA). The characteristics of resistant HTN that predispose patients to OSA have not been reported. Therefore, we aimed to determine the clinical, laboratory, and polysomnographic features of resistant HTN that are significantly associated with OSA. Materials and Methods: Hypertensive patients (n=475) who underwent portable polysomnography were enrolled. The patients were categorized into controlled (n=410) and resistant HTN (n=65) groups. The risk factors for the occurrence of OSA in controlled and resistant hypertensive patients were compared, and independent risk factors that are associated with OSA were analyzed. Materials and Methods: Hypertensive patients (n=475) who underwent portable polysomnography were enrolled. The patients were categorized into controlled (n=410) and resistant HTN (n=65) groups. The risk factors for the occurrence of OSA in controlled and resistant hypertensive patients were compared, and independent risk factors that are associated with OSA were analyzed. Conclusion: The higher prevalence and severity of OSA in resistant HTN may be due to the association of risk factors that are common to both conditions. [ABSTRACT FROM AUTHOR]

Most embedded systems are equipped with flash memory owing to its shock resistance, fast access, and low power consumption. However, some of its distinguishing characteristics, including out-of-place updates, an asymmetric read/write/erase speed, and a limited number of write/erase cycles, make it necessary to reconsider the existing system designs to explore its performance potential. For example, the buffer replacement policy of flash-based systems should not only consider the cache hit ratio, but also the relative heavy write and erase costs that are caused by flushing dirty pages. Most of the recent studies on buffer designs have focused on a Clean-First LRU strategy that evicts clean pages preferentially to reduce the number of writes to flash memory. However, each of them fails to distinguish dirty pages, which may have a different effect on the flash memory. In this paper, we propose a Lazy-Split LRU-based buffer management scheme that not only considers an imbalance of the read and write speeds but also different effects of different dirty pages and frequent changes of the B+-tree index structure caused by intensive overwrites. Specifically, it introduces a semi-clean state to further classify some dirty pages into clean part and dirty part and several efficient replacement policies to reduce the number of B+-tree splits. The experimental results show that our solution outperforms other algorithms including pure LRU and CFDC, and is effective and efficient for improving the performance of B'-tree on flash memory. [ABSTRACT FROM AUTHOR]

Purpose: Obstructive sleep apnea (OSA) is considered an independent risk factor for hypertension. However, it is still not clear which clinical factors are related with the presence of hypertension in OSA patients. We aimed to find different physical features and compare the sleep study results which are associated with the occurrence of hypertension in OSA patients. Materials and Methods: Medical records were retrospectively reviewed for patients diagnosed with OSA at Severance Cardiovascular Hospital between 2010 and 2013. Males with moderate to severe OSA patients were enrolled in this study. Clinical and polysomnographic features were evaluated to assess clinical variables that are significantly associated with hypertension by statistical analysis. Results: Among men with moderate to severe OSA, age was negatively correlated with hypertension (odds ratio=0.956), while neck circumference was positively correlated with the presence of hypertension (odds ratio=1.363). Among the polysomnographic results, the lowest O2 saturation during sleep was significantly associated with the presence of hypertension (odds ratio=0.900). Conclusion: Age and neck circumference should be considered as clinically significant features, and the lowest blood O2 saturation during sleep should be emphasized in predicting the coexistence or development of hypertension in OSA patients. [ABSTRACT FROM AUTHOR]

Cystic fibrosis (CF) results from mutations that disrupt CF transmembrane conductance regulator (CFTR), an anion channel found mainly in apical membranes of epithelial cells. CF leads to chronic infection of the airways with normally innocuous bacteria and fungi. Hypotheses to explain the pathophysiology of CF airways have been difficult to test because mouse models of CF do not develop human-like airway disease. The recent production of pigs lacking CFTR and pigs expressing the most common CF-causing CFTR mutant, DeltaF508, provide another model that might help clarify the pathophysiology of CF airway disease. Here, we studied individual submucosal glands from 1-day-old piglets in situ in explanted tracheas, using optical methods to monitor mucus secretion rates from multiple glands in parallel. Secretion rates from control piglets (WT and CFTR+/-) and piglets with CF-like disease (CFTR-/- and CFTR-/DeltaF508) were measured under 5 conditions: unstimulated (to determine basal secretion), stimulated with forskolin, stimulated with carbachol, stimulated with substance P, and, as a test for synergy, stimulated with forskolin and a low concentration of carbachol. Glands from piglets with CF-like disease responded qualitatively to all agonists like glands from human patients with CF, producing virtually no fluid in response to stimulation with forskolin and substantially less in response to all other agonists except carbachol. These data are a step toward determining whether gland secretory defects contribute to CF airway disease. [ABSTRACT FROM AUTHOR]

Mucus secretion from individual tracheal glands in adult ferrets was studied with time-lapse optical imaging of mucus droplets under an oil layer. Density of functional glands (determined by responses to 1 µM carbachol) was 1.5 ± 0.3 per mm² (n = 6). Secretion rates (in pl·min-1·gland-1) were as follows: 4.1 ± 0.7 basal (unstimulated: n = 27, 669 glands), 338 ± 70 to 10 µM forskolin (n = 8, 90 glands), 234 ± 13 to 1 µM VIP (n = 6, 57 glands), 183 ± 92 to 10 µM isoproterenol (n = 3, 33 glands), 978 ± 145 to 1 µM carbachol (n = 11, 131 glands), and 1,348 ± 325 to 10 µM phenylephrine (n = 7,74 glands). The potency (EC50, in µM) and efficacy (Vmax, in pl·min-1·gland-1) were 7.6 (EC50) and 338 ± 16 (Vmax) to forskolin, 1.0 (EC50) and 479 ± 19 (Vmax) to VIP, 0.6 (EC50) and 1,817 ± 268 (Vmax) to carbachol, and 3.7 (EC50) and 1,801 ± 95 (Vmax) to phenylephrine. Although carbachol and phenylephrine were equally effective secretagogues, only carbachol caused contractions of the trachealis muscle. Synergy was demonstrated between 300 nM isoproterenol and 100 nM carbachol, which, when combined, produced a secretion rate almost fourfold greater than predicted from their additive effect. The dependence of fluid secretion on Cl- and HCO3 varied depending on the mode of stimulation. Secretion stimulated by VIP or forskolin was reduced by ~60% by blocking either anion, while carbachol-stimulated secretion was blocked 68% by bumet-anide and only 32% by HEPES replacement of HCO3-. These results provide parametric data for comparison with fluid secretion from glands in tenets lacking CFTR. [ABSTRACT FROM AUTHOR]

Cystic fibrosis (CF) is a recessive disease that affects multiple organs. It is caused by mutations in CFTR. Animal modeling of this disease has been challenging, with species- and strain-specific differences in organ biology and CFTR function influencing the emergence of disease pathology. Here, we report the phenotype of a CFTR-knockout ferret model of CF. Neonatal CFTR-knockout ferrets demonstrated many of the characteristics of human CF disease, including defective airway chloride transport and submucosal gland fluid secretion; variably penetrant meconium ileus (MI); pancreatic, liver, and vas deferens disease; and a predisposition to lung infection in the early postnatal period. Severe malabsorption by the gastrointestinal (GI) tract was the primary cause of death in CFTR-knockout kits that escaped MI. Elevated liver function tests in CFTR-knockout kits were corrected by oral administration of ursodeoxycholic acid, and the addition of an oral proton-pump inhibitor improved weight gain and survival. To overcome the limitations imposed by the severe intestinal phenotype, we cloned 4 gut-corrected transgenic CFTR-knockout kits that expressed ferret CFTR specifically in the intestine. One clone passed feces normally and demonstrated no detectable ferret CFTR expression in the lung or liver. The animals described in this study are likely to be useful tools for dissecting CF disease pathogenesis and developing treatments. [ABSTRACT FROM AUTHOR]