2,237 research outputs found
Nonlinear photoacoustic microscopy via a loss modulation technique: from detection to imaging
In order to achieve high-resolution deep-tissue imaging, multi-photon fluorescence microscopy and photoacoustic tomography had been proposed in the past two decades. However, combining the advantages of these two imaging systems to achieve optical-spatial resolution with an ultrasonic-penetration depth is still a field with challenges. In this paper, we investigate the detection of the two-photon photoacoustic ultrasound, and first demonstrate background-free two-photon photoacoustic imaging in a phantom sample. To generate the background-free two-photon photoacoustic signals, we used a high-repetition rate femtosecond laser to induce narrowband excitation. Combining a loss modulation technique, we successfully created a beating on the light intensity, which not only provides pure sinusoidal modulation, but also ensures the spectrum sensitivity and frequency selectivity. By using the lock-in detection, the power dependency experiment validates our methodology to frequency-select the source of the nonlinearity. This ensures our capability of measuring the background-free two-photon photoacoustic waves by detecting the 2nd order beating signal directly. Furthermore, by mixing the nanoparticles and fluorescence dyes as contrast agents, the two-photon photoacoustic signal was found to be enhanced and detected. In the end, we demonstrate subsurface two-photon photoacoustic bio-imaging based on the optical scanning mechanism inside phantom samples
Theoretical study of the ammonia nitridation rate on an Fe (100) surface: A combined density functional theory and kinetic Monte Carlo study
Ammonia (NH[subscript 3]) nitridation on an Fe surface was studied by combining density functional theory (DFT) and kinetic Monte Carlo (kMC) calculations. A DFT calculation was performed to obtain the energy barriers (E[subscript b]) of the relevant elementary processes. The full mechanism of the exact reaction path was divided into five steps (adsorption, dissociation, surface migration, penetration, and diffusion) on an Fe (100) surface pre-covered with nitrogen. The energy barrier (E[subscript b]) depended on the N surface coverage. The DFT results were subsequently employed as a database for the kMC simulations. We then evaluated the NH[subscript 3] nitridation rate on the N pre-covered Fe surface. To determine the conditions necessary for a rapid NH[subscript 3] nitridation rate, the eight reaction events were considered in the kMC simulations: adsorption, desorption, dissociation, reverse dissociation, surface migration, penetration, reverse penetration, and diffusion. This study provides a real-time-scale simulation of NH[subscript 3] nitridation influenced by nitrogen surface coverage that allowed us to theoretically determine a nitrogen coverage (0.56 ML) suitable for rapid NH[subscript 3] nitridation. In this way, we were able to reveal the coverage dependence of the nitridation reaction using the combined DFT and kMC simulations.Korea (South). Ministry of Education, Science and Technology (MEST) (National Research Foundation of Korea. 2011-0028612
What do they eat? A survey of eat-out habit of university students in Taiwan
[EN] Main purpose of this research is trying to understand food likeliness of
Taiwan college students, and probe whether these food are healthy. Three
survey steps are taken as: step 1, market survey for what kind of foods are
selling around the campuses; step 2, questionnaire investigation for students
food preference; step 3, analyzing whether these favorite foods are healthy or
not. The result shows: major consideration for students food selection are
“taste” and “price”; 63% of students are taking food or snacks late at night
at least once a week. Top three most favorite foods are: Taiwanese fries (yan
su ji), carbon grilled chicken and fried fish steaks. Quantities of these foods
are small, prices are low, and easy access from roadside food stands.
Problems of them are high calories, easy to accumulate free radical in
human body, plus insanitary food processing environment. They are harmful
to student health. We suggest Taiwan government take it seriouslyShih, K.; Wang, M.; Shih, H.; Lee, S.; Lin, T. (2020). What do they eat? A survey of eat-out habit of university students in Taiwan. Editorial Universitat Politècnica de València. 421-430. https://doi.org/10.4995/INN2019.2019.10562OCS42143
Nursing Students’ Clinical Confidence In Caring Tuberculosis: Indonesian Version Of The U.S Tuberculosis Curriculum Consortium Survey Using Rasch Analysis
Background: Nursing students who are prepared in clinical practicums to comprehend the knowledge, reflect their beliefs about tuberculosis instruction, and perceive their abilities in caring for tuberculosis patients are also at risk. Nursing students’ clinical confidence in caring for tuberculosis patients is essential to be assessed. Knowledge, beliefs, and clinical confidence, as unidimensional constructs based on Bandura’s theory of self-efficacy, had been used in the US National Tuberculosis Curriculum Consortium (NTCC) survey for nursing students. This study's objective was to investigate the Indonesian version of the NTCC survey among nursing students' experiences caring for tuberculosis patients.
Methods: A quantitative study with cross-sectional using an online survey among 250 students 1st to 3rd-yearrd year students in one faculty of nursing in Banten, Indonesia. Prior to data collection, NTCC surveys were translated backward and forward, reviewed by experts, and tested in a pilot project.
Results: Internal consistency using Rasch analysis on each subscale showed good results and gave strong evidence that three subscales are unidimensional. There was an item separation index and reliability score, in that order: knowledge about tuberculosis (8.68 and 0.99), beliefs regarding tuberculosis instructions (6.50 and 0.98), and clinical confidence in caring for tuberculosis patients (6.29 and 0.98).
Conclusion: The Indonesian version of the NTCC survey has excellent internal consistency. This instrument might be improved since the original instrument is 13 years old and there is a cultural gap between the US and Indonesia. Moreover, this instrument might be needed for improving tuberculosis teaching in the nursing curriculum in Indonesia
Phylo-mLogo: an interactive and hierarchical multiple-logo visualization tool for alignment of many sequences
BACKGROUND: When aligning several hundreds or thousands of sequences, such as epidemic virus sequences or homologous/orthologous sequences of some big gene families, to reconstruct the epidemiological history or their phylogenies, how to analyze and visualize the alignment results of many sequences has become a new challenge for computational biologists. Although there are several tools available for visualization of very long sequence alignments, few of them are applicable to the alignments of many sequences. RESULTS: A multiple-logo alignment visualization tool, called Phylo-mLogo, is presented in this paper. Phylo-mLogo calculates the variabilities and homogeneities of alignment sequences by base frequencies or entropies. Different from the traditional representations of sequence logos, Phylo-mLogo not only displays the global logo patterns of the whole alignment of multiple sequences, but also demonstrates their local homologous logos for each clade hierarchically. In addition, Phylo-mLogo also allows the user to focus only on the analysis of some important, structurally or functionally constrained sites in the alignment selected by the user or by built-in automatic calculation. CONCLUSION: With Phylo-mLogo, the user can symbolically and hierarchically visualize hundreds of aligned sequences simultaneously and easily check the changes of their amino acid sites when analyzing many homologous/orthologous or influenza virus sequences. More information of Phylo-mLogo can be found at URL
Modeling and Simulation of Spark Streaming
As more and more devices connect to Internet of Things, unbounded streams of
data will be generated, which have to be processed "on the fly" in order to
trigger automated actions and deliver real-time services. Spark Streaming is a
popular realtime stream processing framework. To make efficient use of Spark
Streaming and achieve stable stream processing, it requires a careful interplay
between different parameter configurations. Mistakes may lead to significant
resource overprovisioning and bad performance. To alleviate such issues, this
paper develops an executable and configurable model named SSP (stands for Spark
Streaming Processing) to model and simulate Spark Streaming. SSP is written in
ABS, which is a formal, executable, and object-oriented language for modeling
distributed systems by means of concurrent object groups. SSP allows users to
rapidly evaluate and compare different parameter configurations without
deploying their applications on a cluster/cloud. The simulation results show
that SSP is able to mimic Spark Streaming in different scenarios.Comment: 7 pages and 13 figures. This paper is published in IEEE 32nd
International Conference on Advanced Information Networking and Applications
(AINA 2018
Spatially resolved MaNGA observations of the host galaxy of superluminous supernova 2017egm
Superluminous supernovae (SLSNe) are found predominantly in dwarf galaxies,
indicating that their progenitors have a low metallicity. However, the most
nearby SLSN to date, SN 2017egm, occurred in the spiral galaxy NGC 3191, which
has a relatively high stellar mass and correspondingly high metallicity. In
this paper, we present detailed analysis of the nearby environment of SN
2017egm using MaNGA IFU data, which provides spectral data on kiloparsec
scales. From the velocity map we find no evidence that SN 2017egm occurred
within some intervening satellite galaxy, and at the SN position most
metallicity diagnostics yield a solar and above solar metallicity (12 + log
(O/H) = 8.8-9.1). Additionally we measure a small H-alpha equivalent width (EW)
at the SN position of just 34 Angs, which is one of the lowest EWs measured at
any SLSN or Gamma-Ray Burst position, and indicative of the progenitor star
being comparatively old. We also compare the observed properties of NGC 3191
with other SLSN host galaxies. The solar-metallicity environment at the
position of SN 2017egm presents a challenge to our theoretical understanding,
and our spatially resolved spectral analysis provides further constraints on
the progenitors of SLSNe.Comment: Accepted version in ApJ Letter. Thank you for useful comment
ATIVS: analytical tool for influenza virus surveillance
The WHO Global Influenza Surveillance Network has routinely performed genetic and antigenic analyses of human influenza viruses to monitor influenza activity. Although these analyses provide supporting data for the selection of vaccine strains, it seems desirable to have user-friendly tools to visualize the antigenic evolution of influenza viruses for the purpose of surveillance. To meet this need, we have developed a web server, ATIVS (Analytical Tool for Influenza Virus Surveillance), for analyzing serological data of all influenza viruses and hemagglutinin sequence data of human influenza A/H3N2 viruses so as to generate antigenic maps for influenza surveillance and vaccine strain selection. Functionalities are described and examples are provided to illustrate its usefulness and performance. The ATIVS web server is available at http://influenza.nhri.org.tw/ATIVS/
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