80 research outputs found
Synchronizing Vision and Language: Bidirectional Token-Masking AutoEncoder for Referring Image Segmentation
Referring Image Segmentation (RIS) aims to segment target objects expressed
in natural language within a scene at the pixel level. Various recent RIS
models have achieved state-of-the-art performance by generating contextual
tokens to model multimodal features from pretrained encoders and effectively
fusing them using transformer-based cross-modal attention. While these methods
match language features with image features to effectively identify likely
target objects, they often struggle to correctly understand contextual
information in complex and ambiguous sentences and scenes. To address this
issue, we propose a novel bidirectional token-masking autoencoder (BTMAE)
inspired by the masked autoencoder (MAE). The proposed model learns the context
of image-to-language and language-to-image by reconstructing missing features
in both image and language features at the token level. In other words, this
approach involves mutually complementing across the features of images and
language, with a focus on enabling the network to understand interconnected
deep contextual information between the two modalities. This learning method
enhances the robustness of RIS performance in complex sentences and scenes. Our
BTMAE achieves state-of-the-art performance on three popular datasets, and we
demonstrate the effectiveness of the proposed method through various ablation
studies
Association of coronary artery calcification and serum gamma-glutamyl transferase in Korean
a b s t r a c t Background and objective: Elevated serum gamma-glutamyl transferase (GGT) has been known to be associated with the cardiovascular disease. However, there is a lack of researches on direct examination of relevance between serum GGT and coronary artery calcification (CAC). Accordingly, the aim of this study was to investigate the association between serum GGT levels and the prevalence of CAC in Korean. Methods: The study population consisted of 14,439 male and female adults without coronary artery disease, who were conducted health examination from January 2010 to December 2010. The prevalence of CAC in relation to the quartile groups of serum GGT levels and odds ratio and 95% CI of CAC were analyzed using multiple logistic regression model. Results: The prevalence of CAC increased with increasing GGT quartile (4.6%, 8.7%, 11.8% and 14.7% in the lowest, second, third, highest GGT quartiles, respectively; p < 0.001). In the logistic regression analysis adjusted for multiple variables, odds ratio (95% CI) for the prevalence of CAC comparing the 1st GGT quartile to the 4th quartile were 2.43 (1.94e3.05) for all subjects, 1.49 (1.21e1.85) for men and 1.33 (0.62e2.87) for women. Conclusion: Elevated serum GGT levels were independently associated with the prevalence of CAC. Physicians and health care providers should be observant regarding future development of coronary artery disease among people with increasing concentration of serum GGT
Direct experimental observation of the molecular Jeff=3/2 ground state in the lacunar spinel GaTa4Se8
Strong spin-orbit coupling lifts the degeneracy of t2g orbitals in 5d
transition-metal systems, leaving a Kramers doublet and quartet with effective
angular momentum of Jeff = 1/2 and 3/2, respectively. These spin-orbit
entangled states can host exotic quantum phases such as topological Mott state,
unconventional superconductivity, and quantum spin liquid. The lacunar spinel
GaTa4Se8 was theoretically predicted to form the molecular Jeff = 3/2 ground
state. Experimental verification of its existence is an important first step to
exploring the consequences of the Jeff = 3/2 state. Here, we report direct
experimental evidence of the Jeff = 3/2 state in GaTa4Se8 by means of
excitation spectra of resonant inelastic x-rays scattering at the Ta L3 and L2
edges. We found that the excitations involving the Jeff = 1/2 molecular orbital
were suppressed only at the Ta L2 edge, manifesting the realization of the
molecular Jeff = 3/2 ground state in GaTa4Se8.Comment: 25 pages, 5 figures + Supplementary Materials [10 pages, 5 figures
Validation of the Broselow tape in Korean children using data from a nationwide anthropometric survey: a cross-sectional study
Purpose In Korea, the Broselow tape (BT) is widely used to estimate weight in resuscitation. Validation of BT in Korean children is essential because the tool was developed based on childrenâs weight and height in the United States. The validation was previously performed in a small-scale dataset. The authors aimed to validate BT using the 2005 Korean nationwide anthropometric survey data. Methods From the population used for the survey, we sampled children aged 0-12 years. The weights estimated by BT were compared with measured weights of the children using Bland-Altman analysis with results recorded as percentage differences. We measured the accuracy of BT, defined as within a 10% error of the measured weight, and the concordance of the color-coded zones derived from the estimated and measured weights. The accuracy and concordance were further assessed according to the age groups and body mass index-for-age Z-score ( 2, overweight or obese). Results A total of 108,128 children were enrolled. The mean age was 55.2 ± 37.5 months. The bias was â5.4% (P < 0.001), and the limits of agreement were â28.3% and 17.6%, respectively. The accuracy and concordance of BT were 64.4% and 67.2%, respectively. Differences of no more than 1 color-coded zone between estimated and measured weights accounted for 89.8% and 84.1% of the under- and overweight (or obese) children, respectively. Conclusion BT accurately estimates weight in approximately two-thirds of Korean children. In addition, adjustment of 1 color-coded zone may be considered in children with extreme weight
Identification and thermochemical analysis of high-lignin feedstocks for biofuel and biochemical production
Background - Lignin is a highly abundant biopolymer synthesized by plants as a complex component of plant secondary cell walls. Efforts to utilize lignin-based bioproducts are needed. Results - Herein we identify and characterize the composition and pyrolytic deconstruction characteristics of high-lignin feedstocks. Feedstocks displaying the highest levels of lignin were identified as drupe endocarp biomass arising as agricultural waste from horticultural crops. By performing pyrolysis coupled to gas chromatography-mass spectrometry, we characterized lignin-derived deconstruction products from endocarp biomass and compared these with switchgrass. By comparing individual pyrolytic products, we document higher amounts of acetic acid, 1-hydroxy-2-propanone, acetone and furfural in switchgrass compared to endocarp tissue, which is consistent with high holocellulose relative to lignin. By contrast, greater yields of lignin-based pyrolytic products such as phenol, 2-methoxyphenol, 2-methylphenol, 2-methoxy-4-methylphenol and 4-ethyl-2-methoxyphenol arising from drupe endocarp tissue are documented. Conclusions - Differences in product yield, thermal decomposition rates and molecular species distribution among the feedstocks illustrate the potential of high-lignin endocarp feedstocks to generate valuable chemicals by thermochemical deconstruction
Whole-genome, transcriptome, and methylome analyses provide insights into the evolution of platycoside biosynthesis in Platycodon grandiflorus, a medicinal plant
Triterpenoid saponins (TSs) are common plant defense phytochemicals with potential pharmaceutical properties. Platycodon grandiflorus (Campanulaceae) has been traditionally used to treat bronchitis and asthma in East Asia. The oleanane-type TSs, platycosides, are a major component of the P. grandiflorus root extract. Recent studies show that platycosides exhibit anti-inflammatory, antiobesity, anticancer, antiviral, and antiallergy properties. However, the evolutionary history of platycoside biosynthesis genes remains unknown. In this study, we sequenced the genome of P. grandiflorus and investigated the genes involved in platycoside biosynthesis. The draft genome of P. grandiflorus is 680.1Mb long and contains 40,017 protein-coding genes. Genomic analysis revealed that the CYP716 family genes play a major role in platycoside oxidation. The CYP716 gene family of P. grandiflorus was much larger than that of other Asterid species. Orthologous gene annotation also revealed the expansion of beta -amyrin synthases (bASs) in P. grandiflorus, which was confirmed by tissue-specific gene expression. In these expanded gene families, we identified key genes showing preferential expression in roots and association with platycoside biosynthesis. In addition, whole-genome bisulfite sequencing showed that CYP716 and bAS genes are hypomethylated in P. grandiflorus, suggesting that epigenetic modification of these two gene families affects platycoside biosynthesis. Thus whole-genome, transcriptome, and methylome data of P. grandiflorus provide novel insights into the regulation of platycoside biosynthesis by CYP716 and bAS gene families
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Production of green aromatics and olefins from lignocellulosic biomass by catalytic fast pyrolysis: Chemistry, catalysis, and process development
Diminishing petroleum resources combined with concerns about global warming and dependence on fossil fuels are leading our society to search for renewable sources of energy. In this respect, lignocellulosic biomass has a tremendous potential as a renewable energy source, once we develop the economical processes converting biomass into useful fuels and chemicals. Catalytic fast pyrolysis (CFP) is a promising technology for production of gasoline range aromatics, including benzene, toluene, and xylenes (BTX), directly from raw solid biomass. In this single step process, solid biomass is fed into a catalytic reactor in which the biomass first thermally decomposes to form pyrolysis vapors. These pyrolysis vapors then enter the zeolite catalysts and are converted into the desired aromatics and olefins along with CO, CO 2, H2O, and coke. The major challenge with the CFP process is controlling the complicated homogeneous and heterogeneous reaction chemistry. The focus of this thesis is to study the reaction chemistry, catalyst design, and process development for CFP to advance the CFP technology. To gain a fundamental understanding of the underlying chemistry of the process, we studied the reaction chemistry for CFP of glucose (i.e. biomass model compound). Glucose is thermally decomposed in a few seconds and produce dehydrated products, including anhydrosugars and furans. The dehydrated products then enter into the zeolite catalyst pore where they are converted into aromatics, CO, CO 2, H2O and coke. The zeolite catalyzed step is far slower than the initial decomposition step (\u3e2 min). Isotopic labeling studies revealed that the aromatics are formed from random hydrocarbon fragments composed of the dehydrated products. The major competing reaction to aromatic production is the formation of coke. The main coking reaction is the polymerization of the furan intermediates on the catalyst surface. CFP is a shape selective reaction where the product selectivity is related to the zeolite pore size and structure. The shape selectivity of the zeolite catalysts in the CFP of glucose was systematically studied with different zeolites. The aromatic yield is a function of the pore size and internal pore space of the zeolite catalyst. Medium pore zeolites with pore sizes in the range of 5.2 to 5.9 Ă
and moderate pore intersection size, such as ZSM-5 and ZSM-11 produced the highest aromatic yield and least amount of coke. The kinetic diameter estimation of the aromatic products and the reactants revealed that the majority of these molecules can fit inside the zeolite pores of the medium pore zeolites. The ZSM-5 catalyst, the best catalyst for aromatic production, was modified further to improve its catalytic performance. These modifications include: (1) adjusting the concentration of acid sites inside the zeolites catalyst; (2) incorporation of mesoporosity into the ZSM-5 framework to enhance its diffusion characteristics, and (3) addition of Ga to the ZSM-5. Mesoporous ZSM-5 showed high selectivity for heavier alkylated monoaromatics. Ga promoted ZSM-5 increased the aromatic yield over 40%. A process development unit was designed and built for continuous operation of the CFP process in a pilot scale. The effects of process variables such as temperature, biomass weight hourly space velocity, catalyst to biomass ratio, catalyst static bed height, and fluidization gas velocity were studied to optimize the reactor performance. It was demonstrated that CFP could produce liter quantities of aromatic products directly from solid biomass
DielsâAlder Cycloaddition of Biomass-Derived 2,5-Dimethylfuran and Ethylene over Sulfated and Phosphated Metal Oxides for Renewable p-Xylene
In this work, sulfated and phosphated metal oxides were studied as catalysts for the DielsâAlder cycloaddition of biomass-derived 2,5-dimethylfuran (DMF) and ethylene to understand the effect of acid strength on the reaction. Four catalysts with varied acidity, namely sulfated SiO2, sulfated TiO2, phosphated SiO2, and phosphated TiO2, were prepared via wet impregnation using sulfuric acid and phosphoric acid as precursors, and their structural and acid properties were examined using X-ray diffraction, BrunauerâEmmettâTeller analysis, Fourier transform infrared spectroscopy, solid state 31P magic angle spinning nuclear magnetic resonance spectroscopy, and temperature programmed desorption of ammonia. The results revealed that the acidity of the catalysts was largely influenced by the type of the acid functional group and the support as well as the calcination temperature. The conversion of DMF and the selectivity toward p-Xylene (PX) were generally correlated with the total acid site density and the acidâmetal oxide interaction strength, which in turn affected the acid strength. Overall, phosphated SiO2 and TiO2 calcined at 773 K were identified as the most active and selective catalysts, exhibiting a high PX selectivity of over 70% and DMF conversion of 80% at 523 K after 6 h. The origin of the stability of the highly active phosphated catalysts was also investigated in detail
Development of multi-module arranged in series using U-type longitudinal fin tube in thermal energy storage system
The performance of a thermal energy storage (TES) system for commercial applications can be improved using phase change materials (PCM). This study develops a vertical multi-module from a PCM for a TES system that achieves the same effect as a single-module by arranging multiple-modules in series as a U-type longitudinal fin tube to enhance the system's performance. The U-type longitudinal fin tube is designed to enhance heat transfer within the module, and a single-module is designed for multi-module applications. The TES system is analyzed to the average heat transfer rate, overall heat transfer coefficient, quantity of heat storage/release, and utilization ratio at different heat transfer fluid (HTF) flow rates, inlet and outlet temperatures and different number of modules. Consequently, the addition of several modules improves the thermal performance, and an increase in the HTF flow rate improves the average heat transfer rate. The overall heat transfer coefficient is used to analyze the thermal characteristics of the PCM. During the heat charging and discharging processes, the average heat transfer rates are 2.4 and 2.55Â kW, respectively, and the quantities of heat storage and release are 5,153.59 and 4,771.79Â kJ, respectively, for three modules. The overall heat transfer coefficient of the PCM exhibits similar results with an increasing HTF flow rate; it increases marginally from 42.25 to 45.8 and 9.9â10.8 Wâmâ2âKâ1 as more modules are added. Further, the results of this study confirm that the relatively low HTF flow rates in the multi-module require the addition of several modules and that increasing the HTF flow rates limits the number of modules
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