Determinants of gastric cancer screening attendance in Korea: a multi-level analysis

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Abstract Background We aimed to assess individual and area-level determinants of gastric cancer screening participation. Method Data on gastric cancer screening and individual-level characteristics were obtained from the 2007–2009 Fourth Korea National Health and Nutrition Examination Survey. The area-level variables were collected from the 2005 National Population Census, 2008 Korea Medical Association, and 2010 National Health Insurance Corporation. The data were analyzed using multilevel logistic regression models. Results The estimated participation rate in gastric cancer screening adhered to the Korea National Cancer Screening Program guidelines was 44.0% among 10,658 individuals aged over 40 years who were included in the analysis. Among the individual-level variables, the highest income quartile, a college or higher education level, living with spouse, having a private health insurance, limited general activity, previous history of gastric or duodenal ulcer, and not currently smoking were associated with a higher participation rate in gastric cancer screening. Urbanization showed a significant negative association with gastric cancer screening attendance among the area-level factors (odds ratio (OR) = 0.73; 95% confidence interval (CI) = 0.57-0.93 for the most urbanized quartile vs. least urbanized quartile). Conclusion There are differences in gastric cancer screening attendance according to both individual and regional area characteristics

Direct Observation of Cooperative Protein Structural Dynamics of Homodimeric Hemoglobin from 100 ps to 10 ms with Pump–Probe X-ray Solution Scattering

Proteins serve as molecular machines in performing their biological functions, but the detailed structural transitions are difficult to observe in their native aqueous environments in real time. For example, despite extensive studies, the solution-phase structures of the intermediates along the allosteric pathways for the transitions between the relaxed (R) and tense (T) forms have been elusive. In this work, we employed picosecond X-ray solution scattering and novel structural analysis to track the details of the structural dynamics of wild-type homodimeric hemoglobin (HbI) from the clam Scapharca inaequivalvis and its F97Y mutant over a wide time range from 100 ps to 56.2 ms. From kinetic analysis of the measured time-resolved X-ray solution scattering data, we identified three structurally distinct intermediates (I-1, I-2, and I-3) and their kinetic pathways common for both the wild type and the mutant. The data revealed that the singly liganded and unliganded forms of each intermediate share the same structure, providing direct evidence that the ligand photolysis of only a single subunit induces the same structural change as the complete photolysis of both subunits does. In addition, by applying novel structural analysis to the scattering data, we elucidated the detailed structural changes in the protein, including changes in the heme heme distance, the quaternary rotation angle of subunits, and interfacial water gain/loss. The earliest, R-like I-1 intermediate is generated within 100 ps and transforms to the R-like I-2 intermediate with a time constant of 3.2 +/- 0.2 ns. Subsequently, the late, T-like I-3 intermediate is formed via subunit rotation, a decrease in the heme-heme distance, and substantial gain of interfacial water and exhibits ligation-dependent formation kinetics with time constants of 730 +/- 120 ns for the fully photolyzed form and 5.6 +/- 0.8 mu s for the partially photolyzed form. For the mutant, the overall kinetics are accelerated, and the formation of the T-like I-3 intermediate involves interfacial water loss (instead of water entry) and lacks the contraction of the heme-heme distance, thus underscoring the dramatic effect of the F97Y mutation. The ability to keep track of the detailed movements of the protein in aqueous solution in real time provides new insights into the protein structural dynamics.1149sciescopu

SVD-aided non-orthogonal decomposition (SANOD) method to exploit prior knowledge of spectral components in the analysis of time-resolved data

Analysis of time-resolved data typically involves discriminating noise against the signal and extracting time-independent components and their time-dependent contributions. Singular value decomposition (SVD) serves this purpose well, but the extracted time-independent components are not necessarily the physically meaningful spectra directly representing the actual dynamic or kinetic processes but rather a mathematically orthogonal set necessary for constituting the physically meaningful spectra. Converting the orthogonal components into physically meaningful spectra requires subsequent posterior analyses such as linear combination fitting (LCF) and global fitting (GF), which takes advantage of prior knowledge about the data but requires that all components are known or satisfactory components are guessed. Since in general not all components are known, they have to be guessed and tested via trial and error. In this work, we introduce a method, which is termed SVD-aided Non-Orthogonal Decomposition (SANOD), to circumvent trial and error. The key concept of SANOD is to combine the orthogonal components from SVD with the known prior knowledge to fill in the gap of the unknown signal components and to use them for LCF. We demonstrate the usefulness of SANOD via applications to a variety of cases. © 2019 Author(s

Ultrafast X-ray crystallography and liquidography

Time-resolved X-ray diffraction provides direct information on three-dimensional structures of reacting molecules and thus can be used to elucidate structural dynamics of chemical and biological reactions. In this review, we discuss time-resolved X-ray diffraction on small molecules and proteins with particular emphasis on its application to crystalline (crystallography) and liquid-solution (liquidography) samples. Time-resolved X-ray diffraction has been used to study picosecond and slower dynamics at synchrotrons and can now access even femtosecond dynamics with the recent arrival of X-ray free-electron lasers. (c) 2017 by Annual Reviews.All rights reserved2

Region-Based Collision Avoidance Beaconless Geographic Routing Protocol in Wireless Sensor Networks

Due to the lack of dependency on beacon messages for location exchange, the beaconless geographic routing protocol has attracted considerable attention from the research community. However, existing beaconless geographic routing protocols are likely to generate duplicated data packets when multiple winners in the greedy area are selected. Furthermore, these protocols are designed for a uniform sensor field, so they cannot be directly applied to practical irregular sensor fields with partial voids. To prevent the failure of finding a forwarding node and to remove unnecessary duplication, in this paper, we propose a region-based collision avoidance beaconless geographic routing protocol to increase forwarding opportunities for randomly-deployed sensor networks. By employing different contention priorities into the mutually-communicable nodes and the rest of the nodes in the greedy area, every neighbor node in the greedy area can be used for data forwarding without any packet duplication. Moreover, simulation results are given to demonstrate the increased packet delivery ratio and shorten end-to-end delay, rather than well-referred comparative protocols

Sub-nanosecond secondary geminate recombination in mercury halides HgX2 (X = I, Br) investigated by time-resolved x-ray scattering

© 2019 Author(s).In this work, we present a detailed investigation on the recombination dynamics of mercury halides HgX2 (X = I, Br) in acetonitrile solution after UV-induced photodissociation. The study is performed by combining time-resolved wide-angle x-ray scattering (TRWAXS) and optical transient absorption spectroscopy. Up to 68% of the UV (266 nm) photodissociated HgX and X radicals that escape the solvent cage surrounding parent HgX2 recombine within a nanosecond after photodissociation. In contrast to classical primary geminate recombination, occurring on much faster time scales, we interpret the sub-nanosecond recombination channel as secondary geminate recombination (SGR), also referred to as diffusion-limited geminate recombination. The family of triatomic mercury halides therefore represents an important class of molecules to study chemical mechanisms of solvent-dependent SGR by TRWAXS. The methodology described here allows for direct mapping of the time-dependent inter-radical distance distribution function, a critical parameter for the assessment of the SGR dynamics in solution phase and solvation in genera

Estimating signal and noise of time-resolved X-ray solution scattering data at synchrotrons and XFELs

© 2020. J. Synchrotron Rad. Elucidating the structural dynamics of small molecules and proteins in the liquid solution phase is essential to ensure a fundamental understanding of their reaction mechanisms. In this regard, time-resolved X-ray solution scattering (TRXSS), also known as time-resolved X-ray liquidography (TRXL), has been established as a powerful technique for obtaining the structural information of reaction intermediates and products in the liquid solution phase and is expected to be applied to a wider range of molecules in the future. A TRXL experiment is generally performed at the beamline of a synchrotron or an X-ray free-electron laser (XFEL) to provide intense and short X-ray pulses. Considering the limited opportunities to use these facilities, it is necessary to verify the plausibility of a target experiment prior to the actual experiment. For this purpose, a program has been developed, referred to as S-cube, which is short for a Solution Scattering Simulator. This code allows the routine estimation of the shape and signal-to-noise ratio (SNR) of TRXL data from known experimental parameters. Specifically, S-cube calculates the difference scattering curve and the associated quantum noise on the basis of the molecular structure of the target reactant and product, the target solvent, the energy of the pump laser pulse and the specifications of the beamline to be used. Employing a simplified form for the pair-distribution function required to calculate the solute-solvent cross term greatly increases the calculation speed as compared with a typical TRXL data analysis. Demonstrative applications of S-cube are presented, including the estimation of the expected TRXL data and SNR level for the future LCLS-II HE beamlines11sci

A Survey on Real-Time Communications in Wireless Sensor Networks

Generally, various traffic requirements in wireless sensor network are mostly dependent on specific application types, that is, event-driven, continuous, and query-driven types. In these applications, real-time delivery is one of the important research challenges. However, due to harsh networking environment around a node, many researchers usually take different approach from conventional networks. In order to discuss and analyze the advantage or disadvantage of these approaches, some comprehensive survey literatures were published; however they are either out of date or compiled for communication protocols on single layer. Based on this deficiency, in this paper, we present the up-to-date research approaches and discuss the important features related to real-time communications in wireless sensor networks. As for grouping, we categorize the approaches into hard, soft, and firm real-time model. Furthermore, in all these categories, research has been focused on MAC and scheduling and routing according to research area or objective in second level. Finally, the article also suggests potential directions for future research in the field