9,491 research outputs found

    Token Imbalance Adaptation for Radiology Report Generation

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    Imbalanced token distributions naturally exist in text documents, leading neural language models to overfit on frequent tokens. The token imbalance may dampen the robustness of radiology report generators, as complex medical terms appear less frequently but reflect more medical information. In this study, we demonstrate how current state-of-the-art models fail to generate infrequent tokens on two standard benchmark datasets (IU X-RAY and MIMIC-CXR) of radiology report generation. % However, no prior study has proposed methods to adapt infrequent tokens for text generators feeding with medical images. To solve the challenge, we propose the \textbf{T}oken \textbf{Im}balance Adapt\textbf{er} (\textit{TIMER}), aiming to improve generation robustness on infrequent tokens. The model automatically leverages token imbalance by an unlikelihood loss and dynamically optimizes generation processes to augment infrequent tokens. We compare our approach with multiple state-of-the-art methods on the two benchmarks. Experiments demonstrate the effectiveness of our approach in enhancing model robustness overall and infrequent tokens. Our ablation analysis shows that our reinforcement learning method has a major effect in adapting token imbalance for radiology report generation.Comment: Accepted by CHIL202

    Impact of 2-bromopropane on mouse embryonic stem cells and related regulatory mechanisms

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    2-Bromopropane (2-BP), a cleaning agent, is used as an alternative to ozone-depleting solvents. Previously, 2-BP was shown to have cytotoxic effects on mouse blastocysts and is associated with defects in their subsequent development, both in vitro and in vivo. In addition, it was found that 2-BP also has cytotoxic effects on oocyte maturation and subsequent pre- and post implantation development in vitro and in vivo, and significantly reduces the rate of oocyte maturation, fertilization, and embryonic development in vitro. This study shows that 2-BP (5 to 10 μM) induces apoptotic processes in mouse embryonic stem cells (ESC-B5), but exerts no effects at treatment dosages below 5 μM. In ESC-B5 cells, 2-BP directly increased the content of reactive oxygen species (ROS), significantly increased the cytoplasmic free calcium and nitric oxide (NO) levels, triggered a loss of mitochondrial membrane potential (MMP), activated caspases-9 and -3, and induced cell death. Pre-treatment with NO scavengers suppressed the apoptotic biochemical changes induced by 10 μM 2-BP and promoted the gene expression levels of p53 and p21, which are involved in apoptotic signaling. These results demonstrate for the first time that 2-BP triggers apoptosis in mouse embryonic stem cells via ROS, NO and the activation of mitochondria-dependent cell death signaling.Keywords: 2-Bromopropane, apoptosis, oxidative stress, calcium, nitric oxideAfrican Journal of Biotechnology Vol. 12(20), pp. 3012-302

    Facile O-atom insertion into C-C and C-H bonds by a trinuclear copper complex designed to harness a singlet oxene

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    Two trinuclear copper [CuICuICuI(L)]1+ complexes have been prepared with the multidentate ligands (L) 3,3'-(1,4-diazepane-1,4-diyl)bis(1-((2-(dimethylamino)ethyl)(methyl)amino)propan-2-ol) (7-Me) and (3,3'-(1,4-diazepane-1,4-diyl)bis(1-((2-(diethylamino) ethyl)(ethyl) amino)propan-2-ol) (7-Et) as models for the active site of the particulate methane monooxygenase (pMMO). The ligands were designed to form the proper spatial and electronic geometry to harness a "singlet oxene," according to the mechanism previously suggested by our laboratory. Consistent with the design strategy, both [CuICuICuI(L)]1+ reacted with dioxygen to form a putative bis(µ3-oxo)CuIICuIICuIII species, capable of facile O-atom insertion across the central C-C bond of benzil and 2,3-butanedione at ambient temperature and pressure. These complexes also catalyze facile O-atom transfer to the C-H bond of CH3CN to form glycolonitrile. These results, together with our recent biochemical studies on pMMO, provide support for our hypothesis that the hydroxylation site of pMMO contains a trinuclear copper cluster that mediates C-H bond activation by a singlet oxene mechanism

    Crystallization of Adenylylsulfate Reductase from Desulfovibrio gigas: A Strategy Based on Controlled Protein Oligomerization

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    Adenylylsulfate reductase (adenosine 5′-phosphosulfate reductase, APS reductase or APSR, E.C.1.8.99.2) catalyzes the conversion of APS to sulfite in dissimilatory sulfate reduction. APSR was isolated and purified directly from massive anaerobically grown Desulfovibrio gigas, a strict anaerobe, for structure and function investigation. Oligomerization of APSR to form dimers–α_2β_2, tetramers–α_4β_4, hexamers–α_6β_6, and larger oligomers was observed during purification of the protein. Dynamic light scattering and ultracentrifugation revealed that the addition of adenosine monophosphate (AMP) or adenosine 5′-phosphosulfate (APS) disrupts the oligomerization, indicating that AMP or APS binding to the APSR dissociates the inactive hexamers into functional dimers. Treatment of APSR with β-mercaptoethanol decreased the enzyme size from a hexamer to a dimer, probably by disrupting the disulfide Cys156—Cys162 toward the C-terminus of the β-subunit. Alignment of the APSR sequences from D. gigas and A. fulgidus revealed the largest differences in this region of the β-subunit, with the D. gigas APSR containing 16 additional amino acids with the Cys156—Cys162 disulfide. Studies in a pH gradient showed that the diameter of the APSR decreased progressively with acidic pH. To crystallize the APSR for structure determination, we optimized conditions to generate a homogeneous and stable form of APSR by combining dynamic light scattering, ultracentrifugation, and electron paramagnetic resonance methods to analyze the various oligomeric states of the enzyme in varied environments

    Known-groups validity of the Patient-Reported Outcomes Measurement Information System (PROMIS®) in adolescents and young adults with special healthcare needs

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    To examine known-groups validity of the Patient-Reported Outcomes Measurement Information System (PROMIS®) Short Forms (SFs) for adolescents and young adults with special health care needs (SHCN) using data collected from the PROMIS Linking Study

    Dihydrolipoic Acid Induces Cytotoxicity in Mouse Blastocysts through Apoptosis Processes

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    α-Lipoic acid (LA) is a thiol with antioxidant properties that protects against oxidative stress-induced apoptosis. LA is absorbed from the diet, taken up by cells and tissues, and subsequently reduced to dihydrolipoic acid (DHLA). In view of the recent application of DHLA as a hydrophilic nanomaterial preparation, determination of its biosafety profile is essential. In the current study, we examined the cytotoxic effects of DHLA on mouse embryos at the blastocyst stage, subsequent embryonic attachment and outgrowth in vitro, in vivo implantation by embryo transfer, and early embryonic development in an animal model. Blastocysts treated with 50 μM DHLA exhibited significantly increased apoptosis and a corresponding decrease in total cell number. Notably, the implantation success rates of blastocysts pretreated with DHLA were lower than that of their control counterparts. Moreover, in vitro treatment with 50 μM DHLA was associated with increased resorption of post-implantation embryos and decreased fetal weight. Data obtained using an in vivo mouse model further disclosed that consumption of drinking water containing 100 μM DHLA led to decreased early embryo development, specifically, inhibition of development to the blastocyst stage. However, it appears that concentrations of DHLA lower than 50 μM do not exert a hazardous effect on embryonic development. Our results collectively indicate that in vitro and in vivo exposure to concentrations of DHLA higher than 50 μM DHLA induces apoptosis and retards early pre- and post-implantation development, and support the potential of DHLA to induce embryonic cytotoxicity

    Rapid intensification of Typhoon Hato (2017) over shallow water

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    © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Pun, I., Chan, J. C. L., Lin, I., Chan, K. T. E., Price, J. F., Ko, D. S., Lien, C., Wu, Y., & Huang, H. Rapid intensification of Typhoon Hato (2017) over shallow water. Sustainability, 11(13), (2019): 3709, doi:10.3390/su11133709.On 23 August, 2017, Typhoon Hato rapidly intensified by 10 kt within 3 h just prior to landfall in the city of Macau along the South China coast. Hato’s surface winds in excess of 50 m s−1 devastated the city, causing unprecedented damage and social impact. This study reveals that anomalously warm ocean conditions in the nearshore shallow water (depth < 30 m) likely played a key role in Hato’s fast intensification. In particular, cooling of the sea surface temperature (SST) generated by Hato at the critical landfall point was estimated to be only 0.1–0.5 °C. The results from both a simple ocean mixing scheme and full dynamical ocean model indicate that SST cooling was minimized in the shallow coastal waters due to a lack of cool water at depth. Given the nearly invariant SST in the coastal waters, we estimate a large amount of heat flux, i.e., 1.9k W m−2, during the landfall period. Experiments indicate that in the absence of shallow bathymetry, and thus, if nominal cool water had been available for vertical mixing, the SST cooling would have been enhanced from 0.1 °C to 1.4 °C, and sea to air heat flux reduced by about a quarter. Numerical simulations with an atmospheric model suggest that the intensity of Hato was very sensitive to air-sea heat flux in the coastal region, indicating the critical importance of coastal ocean hydrography.The work of I.-F.P. is supported by Taiwan’s Ministry of Science and Technology Grant MOST 107-2111-M-008-001-MY3. The work of J.C.L.C. is supported by the Research Grants Council of Hong Kong Grant E-CityU101/16. The work of I.-I.L. is supported by Taiwan’s Ministry of Science and Technology (MOST 106-2111-M-002-011-MY3, MOST 108-2111-M-002-014-MY2). The work of K.T.F.C. is jointly supported by the National Natural Science Foundation of China (41775097), and the National Natural Science Foundation of China and Macau Science and Technology Development Joint Fund (NSFC-FDCT), China and Macau (41861164027)

    Evaluating the reliability, validity and minimally important difference of the Taiwanese version of the diabetes quality of life (DQOL) measurement

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    <p>Abstract</p> <p>Background</p> <p>Few diabetes HRQOL instruments are available in Chinese language. We tested psychometric properties of a Diabetes Quality of Life (DQOL) in Chinese language for diabetes patients in Taiwan and estimated its minimally important differences (MIDs).</p> <p>Methods</p> <p>Data were collected from 337 patients treated in diabetes clinics of a Taiwan teaching hospital. Pearson's correlations among domain scores of the DQOL (satisfaction, impact, and worry), the D-39S (a diabetes-specific instrument, including domains of diabetes control, energy and mobility, social burden and anxiety and worry, and sexual functioning) and the RAND-12 (a generic instrument, including physical health composite (PHC) and mental health composite (MHC)) were estimated to determine convergent/discriminant validity. Known-groups validity was examined using 2-hour postprandial plasma glucose (2 h PPG), hemoglobin A1c (HbA1c)) and presence of complications (retinopathy, neuropathy, and diabetic foot complications rather than the known groups of cardiovascular and cerebrovascular complications). We used a combined anchor- and distribution-based approach to establish MIDs.</p> <p>Results</p> <p>The DQOL scores were more strongly correlated with the physical domains of the D-39S (diabetes control and energy and mobility) and RAND-12 PHC than psychological domains of the D-39S (social burden, anxiety and worry, and sexual functioning) and RAND-12 MHC. The DQOL showed satisfactory discriminative ability for the known groups of 2 h PPG and HbA1c (effect size (ES) ≥ 0.2) and retinopathy, neuropathy, and diabetic foot complications (ES ≥ 0.3), but less satisfactory for the known groups of cardiovascular and cerebrovascular complications. MIDs for the DQOL domains were 3–5 points for satisfaction, 4–5 points for impact, 6–8 points for worry, and 3–4 points for overall HRQOL.</p> <p>Conclusion</p> <p>We validated a DQOL in Chinese language for diabetes patients in Taiwan and provided MIDs to facilitate the measure of diabetes HRQOL.</p
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