60 research outputs found
Surface-guided computing to analyze subcellular morphology and membrane-associated signals in 3D
Signal transduction and cell function are governed by the spatiotemporal
organization of membrane-associated molecules. Despite significant advances in
visualizing molecular distributions by 3D light microscopy, cell biologists
still have limited quantitative understanding of the processes implicated in
the regulation of molecular signals at the whole cell scale. In particular,
complex and transient cell surface morphologies challenge the complete sampling
of cell geometry, membrane-associated molecular concentration and activity and
the computing of meaningful parameters such as the cofluctuation between
morphology and signals. Here, we introduce u-Unwrap3D, a framework to remap
arbitrarily complex 3D cell surfaces and membrane-associated signals into
equivalent lower dimensional representations. The mappings are bidirectional,
allowing the application of image processing operations in the data
representation best suited for the task and to subsequently present the results
in any of the other representations, including the original 3D cell surface.
Leveraging this surface-guided computing paradigm, we track segmented surface
motifs in 2D to quantify the recruitment of Septin polymers by blebbing events;
we quantify actin enrichment in peripheral ruffles; and we measure the speed of
ruffle movement along topographically complex cell surfaces. Thus, u-Unwrap3D
provides access to spatiotemporal analyses of cell biological parameters on
unconstrained 3D surface geometries and signals.Comment: 49 pages, 10 figure
Impact Analysis of Earthquake-Induced Cracks in Deep Geological Repositories for Nuclear Waste Fuel
Based on the concept of deep geologic repositories, high-level radioactive waste will be stored in deep deposition holes away from the ground surface. The heat generated by the waste will induce both significant stress increments and ground water seepage in a multiple geologic barrier system. The long-term ability of a barrier system is significantly impacted by coupling between the thermal, hydrological, and mechanical processes. The stability of a system may also depend particularly upon unanticipated factors such as the development of
post-earthquake macrocracks. Therefore, this study investigates the three-dimensional transient and long term thermo-hydro-mechanical behavior of a barrier system. The results can be used for future reference in practical engineering design.高放射性用過核燃料所產生之長期衰變熱會對生物圈造成極大衝擊,目前國際上多傾向以深層地質處置作為最終處置之方式。處置過程中,極可能因為地震或地層變動等不可預期之因素,在天然障壁中產生大形裂縫,由此伴隨的災損效應將會加速障壁之劣化。本研究依據我國深層地質處置的初步設計概念,針對天然障壁系統長期之熱-水力-力學耦合效應,利用依序耦合分析方法,考慮不同的裂縫尺寸,針對其可能引致之熱應力與地下水影響進行評估
Sarcocrassocolides M–O, Bioactive Cembranoids from the Dongsha Atoll Soft Coral Sarcophyton crassocaule
Three new cembranoids, sarcocrassocolides M–O (1–3), have been isolated from the soft coral Sarcophyton crassocaule. The structures of the metabolites were determined by extensive spectroscopic analysis. Compounds 1–3 were shown to exhibit moderate cytotoxicity toward a limited panel of cancer cell lines and display significant in vitro anti-inflammatory activity in LPS-stimulated RAW264.7 macrophage cells by inhibiting the expression of the iNOS protein
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Converting lateral scanning into axial focusing to speed up three-dimensional microscopy.
Funder: MedImmune, and Infinitus (China) Ltd.In optical microscopy, the slow axial scanning rate of the objective or the sample has traditionally limited the speed of volumetric imaging. Recently, by conjugating either a movable mirror to the image plane in a remote-focusing geometry or an electrically tuneable lens (ETL) to the back focal plane, rapid axial scanning has been achieved. However, mechanical actuation of a mirror limits the axial scanning rate (usually only 10-100 Hz for piezoelectric or voice coil-based actuators), while ETLs introduce spherical and higher-order aberrations that prevent high-resolution imaging. In an effort to overcome these limitations, we introduce a novel optical design that transforms a lateral-scan motion into a spherical aberration-free axial scan that can be used for high-resolution imaging. Using a galvanometric mirror, we scan a laser beam laterally in a remote-focusing arm, which is then back-reflected from different heights of a mirror in the image space. We characterize the optical performance of this remote-focusing technique and use it to accelerate axially swept light-sheet microscopy by an order of magnitude, allowing the quantification of rapid vesicular dynamics in three dimensions. We also demonstrate resonant remote focusing at 12 kHz with a two-photon raster-scanning microscope, which allows rapid imaging of brain tissues and zebrafish cardiac dynamics with diffraction-limited resolution
Nardosinane-Type Sesquiterpenoids from the Formosan Soft Coral Paralemnalia thyrsoides
Five new nardosinane-type sesquiterpenoids, paralemnolins Q–U (1–5), along with three known compounds (6–8), were isolated from the Formosan soft coral Paralemnalia thyrsoides. The structures of new metabolites were elucidated on the basis of extensive spectroscopic methods, and the absolute configuration of 1 was determined by the application of Mosher’s method on 1. Among these metabolites, 1 and 3 are rarely found nardosinane-type sesquiterpenoids, possessing novel polycyclic structures. Compounds 1, 3, 6 and 7 were found to possess neuroprotective activity
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
Compact Circularly Polarized Tag Antenna for UHF RFID System
Abstract -This work describes a novel compact design of planar circularly polarized (CP) tag antenna for UHF RFID system. By introducing the meander strip into the right-arm of the square-ring structure, the measured half-power bandwidth of the proposed CP tag antenna can be more than 100 MHz (860 ~ 960 MHz), which includes the entire operating bandwidth for worldwide UHF RFID system. The obtained 3 dB axial-ratio (AR) bandwidth can be about 33 MHz (902~935 MHz), suitable for American (902~928 MHz), Euro (918~926 MHz) and Taiwan UHF RFID (922~928 MHz) applications. Since overall antenna dimension is only 54 × 54 mm 2 , the proposed tag antenna in this study can operate with antenna size reduction of 42 % than conventional CP antennas. Meanwhile, with bidirectional reading pattern, the measured reading distance is about 8.5 m. Good tag sensitivity is obtained across the desired frequency band
Home-Based Intelligent Exercise System for Seniors’ Healthcare: The Example of Golf Croquet
In 2020, the world experienced the threat of the COVID-19 epidemic, and seniors and chronic disease patients generally reduced their exercise and social activities to avoid increasing the risk of infection, which could lead to increased loneliness and even many diseases. Combining golf croquet games with a mobile application (App) and AIoT companion robots, this research constructs a home-based intelligent exercise system, uses the technology acceptance model (TAM), deduces users’ intention to use this system based on perceived usefulness and perceived ease of use, and adds the needs of love and belonging, esteem, cognitive, aesthetic, and self-actualization in Maslow’s hierarchy of needs theory (HNT) to conduct an analysis of system needs. This study collected empirical data, totaling 320 participants including seniors and their caregivers, from elderly care centers in northern Taiwan using a cross-sectional survey and purposive sampling. Based on regression and variance analysis, the results show that participants have a high level of acceptance of this system, believing that it is easy to learn and operate and can increase interaction with others, improve self-confirmation, satisfy the thirst for knowledge, increase the feeling of happiness, and fulfill self-actualization needs. In the future, by collecting and recording the process of seniors using the App, so as to find out their health problems as soon as possible, expand their daily life through this exercise, and achieve the goal of happy living and better healthcare
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