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- Abdalla, H., et al.
(author)
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HESS J1741-302 : a hidden accelerator in the Galactic plane
- 2018
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 612
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Journal article (peer-reviewed)abstract
- The H.E.S.S. Collaboration has discovered a new very high energy (VHE, E > 0.1 TeV) gamma-ray source, HESS J1741-302, located in the Galactic plane. Despite several attempts to constrain its nature, no plausible counterpart has been found so far at X-ray and MeV/GeV gamma-ray energies, and the source remains unidentified. An analysis of 145-h of observations of HESS J1741-302 at VHEs has revealed a steady and relatively weak TeV source (similar to 1% of the Crab Nebula flux), with a spectral index of Gamma = 2.3 +/- 0.2(stat) +/- 0.2(sys), extending to energies up to 10 TeV without any clear signature of a cut-off. In a hadronic scenario, such a spectrum implies an object with particle acceleration up to energies of several hundred TeV. Contrary to most H.E.S.S. unidentified sources, the angular size of HESS J1741-302 is compatible with the H.E.S.S. point spread function at VHEs, with an extension constrained to be below 0.068 degrees at a 99% confidence level. The gamma-ray emission detected by H.E.S.S. can be explained both within a hadronic scenario, due to collisions of protons with energies of hundreds of TeV with dense molecular clouds, and in a leptonic scenario, as a relic pulsar wind nebula, possibly powered by the middle-aged (20 kyr) pulsar PSR B1737-30. A binary scenario, related to the compact radio source 1LC 358.266+0.038 found to be spatially coincident with the best fit position of HESS J1741-302, is also envisaged.
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| 6. |
- Nakajima, K., et al.
(author)
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Diagnostic accuracy of an artificial neural network compared with statistical quantitation of myocardial perfusion images: a Japanese multicenter study
- 2017
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In: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 44:13, s. 2280-2289
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Journal article (peer-reviewed)abstract
- Purpose Artificial neural networks (ANN) might help to diagnose coronary artery disease. This study aimed to determine whether the diagnostic accuracy of an ANN-based diagnostic system and conventional quantitation are comparable. Methods The ANN was trained to classify potentially abnormal areas as true or false based on the nuclear cardiology expert interpretation of 1001 gated stress/rest Tc-99m-MIBI images at 12 hospitals. The diagnostic accuracy of the ANN was compared with 364 expert interpretations that served as the gold standard of abnormality for the validation study. Conventional summed stress/rest/difference scores (SSS/SRS/SDS) were calculated and compared with receiver operating characteristics (ROC) analysis. Results The ANN generated a better area under the ROC curves (AUC) than SSS (0.92 vs. 0.82, p < 0.0001), indicating better identification of stress defects. The ANN also generated a better AUC than SDS (0.90 vs. 0.75, p < 0.0001) for stress-induced ischemia. The AUC for patients with old myocardial infarction based on rest defects was 0.97 (0.91 for SRS, p = 0.0061), and that for patients with and without a history of revascularization based on stress defects was 0.94 and 0.90 (p = 0.0055 and p < 0.0001 vs. SSS, respectively). The SSS/SRS/SDS steeply increased when ANN values (probability of abnormality) were > 0.80. Conclusion The ANN was diagnostically accurate in various clinical settings, including that of patients with previous myocardial infarction and coronary revascularization. The ANN could help to diagnose coronary artery disease.
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| 7. |
- Nakajima, K., et al.
(author)
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Diagnostic Performance of Artificial Neural Network for Detecting Ischemia in Myocardial Perfusion Imaging
- 2015
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In: Circulation Journal. - 1346-9843. ; 79:7, s. 1549-1556
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Journal article (peer-reviewed)abstract
- Background: The purpose of this study was to apply an artificial neural network (ANN) in patients with coronary artery disease (CAD) and to characterize its diagnostic ability compared with conventional visual and quantitative methods in myocardial perfusion imaging (MPI). Methods and Results: A total of 106 patients with CAD were studied with MPI, including multiple vessel disease (49%), history of myocardial infarction (27%) and coronary intervention (30%). The ANN detected abnormal areas with a probability of stress defect and ischemia. The consensus diagnosis based on expert interpretation and coronary stenosis was used as the gold standard. The left ventricular ANN value was higher in the stress-defect group than in the no-defect group (0.92 +/- 0.11 vs. 0.25 +/- 0.32, P<0.0001) and higher in the ischemia group than in the noischemia group (0.70 +/- 0.40 vs. 0.004 +/- 0.032, P<0.0001). Receiver-operating characteristics curve analysis showed comparable diagnostic accuracy between ANN and the scoring methods (0.971 vs. 0.980 for stress defect, and 0.882 vs. 0.937 for ischemia, both P=NS). The relationship between the ANN and defect scores was non-linear, with the ANN rapidly increased in ranges of summed stress score of 2-7 and summed defect score of 2-4. Conclusions: Although the diagnostic ability of ANN was similar to that of conventional scoring methods, the ANN could provide a different viewpoint for judging abnormality, and thus is a promising method for evaluating abnormality in MPI.
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| 8. |
- Nakajima, K., et al.
(author)
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Artificial neural network retrained to detect myocardial ischemia using a Japanese multicenter database
- 2018
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In: Annals of Nuclear Medicine. - : Springer Science and Business Media LLC. - 0914-7187 .- 1864-6433. ; 32:5, s. 303-310
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Journal article (peer-reviewed)abstract
- An artificial neural network (ANN) has been applied to detect myocardial perfusion defects and ischemia. The present study compares the diagnostic accuracy of a more recent ANN version (1.1) with the initial version 1.0. We examined 106 patients (age, 77 +/- 10 years) with coronary angiographic findings, comprising multi-vessel disease ( 50% stenosis) (52%) or old myocardial infarction (27%), or who had undergone coronary revascularization (30%). The ANN versions 1.0 and 1.1 were trained in Sweden (n = 1051) and Japan (n = 1001), respectively, using Tc-99m-methoxyisobutylisonitrile myocardial perfusion images. The ANN probabilities (from 0.0 to 1.0) of stress defects and ischemia were calculated in candidate regions of abnormalities. The diagnostic accuracy was compared using receiver-operating characteristics (ROC) analysis and the calculated area under the ROC curve (AUC) using expert interpretation as the gold standard. Although the AUC for stress defects was 0.95 and 0.93 (p = 0.27) for versions 1.1 and 1.0, respectively, that for detecting ischemia was significantly improved in version 1.1 (p = 0.0055): AUC 0.96 for version 1.1 (sensitivity 87%, specificity 96%) vs. 0.89 for version 1.0 (sensitivity 78%, specificity 97%). The improvement in the AUC shown by version 1.1 was also significant for patients with neither coronary revascularization nor old myocardial infarction (p = 0.0093): AUC = 0.98 for version 1.1 (sensitivity 88%, specificity 100%) and 0.88 for version 1.0 (sensitivity 76%, specificity 100%). Intermediate ANN probability between 0.1 and 0.7 was more often calculated by version 1.1 compared with version 1.0, which contributed to the improved diagnostic accuracy. The diagnostic accuracy of the new version was also improved in patients with either single-vessel disease or no stenosis (n = 47; AUC, 0.81 vs. 0.66 vs. p = 0.0060) when coronary stenosis was used as a gold standard. The diagnostic ability of the ANN version 1.1 was improved by retraining using the Japanese database, particularly for identifying ischemia.
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| 9. |
- Rojas-Macias, Miguel A., 1979, et al.
(author)
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Towards a standardized bioinformatics infrastructure for N- and O-glycomics
- 2019
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10
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Journal article (peer-reviewed)abstract
- The mass spectrometry (MS)-based analysis of free polysaccharides and glycans released from proteins, lipids and proteoglycans increasingly relies on databases and software. Here, we review progress in the bioinformatics analysis of protein-released N- and O-linked glycans (N-and O-glycomics) and propose an e-infrastructure to overcome current deficits in data and experimental transparency. This workflow enables the standardized submission of MS-based glycomics information into the public repository UniCarb-DR. It implements the MIRAGE (Minimum Requirement for A Glycomics Experiment) reporting guidelines, storage of unprocessed MS data in the GlycoPOST repository and glycan structure registration using the GlyTouCan registry, thereby supporting the development and extension of a glycan structure knowledgebase.
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| 10. |
- Xu, Su-Yang, et al.
(author)
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Lifshitz transition and Van Hove singularity in a three-dimensional topological Dirac semimetal
- 2015
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In: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 92:7
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Journal article (peer-reviewed)abstract
- A three-dimensional (3D) Dirac semimetal is a novel state of quantum matter which has recently attracted much attention as an apparent 3D version of graphene. In this paper, we report results on the electronic structure of the 3D Dirac semimetal Na3Bi at a surface that reveals its nontrivial ground state. Our studies reveal that the two 3D Dirac cones go through a topological change in the constant energy contour as a function of the binding energy, featuring a Lifshitz point, which is missing in a strict 3D analog of graphene. Our results identify an example of a band saddle-point singularity in 3D Dirac materials. This is in contrast to its two-dimensional analogs such as graphene and the Dirac surface states of a topological insulator. The observation of multiple Dirac nodes in Na3Bi connecting via a Lifshitz point along its crystalline rotational axis away from the Kramers point serves as a decisive signature for the symmetry-protected nature of the Dirac semimetal's topological bulk ground state.
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| 11. |
- Yoneyama, H., et al.
(author)
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Reducing the small-heart effect in pediatric gated myocardial perfusion single-photon emission computed tomography
- 2017
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In: Journal of Nuclear Cardiology. - : Springer Science and Business Media LLC. - 1071-3581 .- 1532-6551. ; 24:4, s. 1378-1388
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Journal article (peer-reviewed)abstract
- Background. We compared two reconstruction algorisms and two cardiac functional evaluation software programs in terms of their accuracy for estimating ejection fraction (EF) of small hearts (SH). Methods. The study group consisted of 66 pediatric patients. Data were reconstructed using a filtered back projection (FBP) method without the resolution correction (RC) and an iterative method based on an ordered subset expectation maximization (OSEM) algorithm with the RC. EF was evaluated using two software programs of quantitative gated single-photon emission computed tomography (SPECT) (QGS) and cardioREPO. We compared the EF of gated myocardial perfusion SPECT to echocardiographic measurement (Echo). Results. Forty-eight of 66 patients had an end-systolic volume < 20 mL which was used as the criterion for being included in the SH group, and the SH effect led to an overestimation of EF. While significant differences were observed between Echo (66.9 +/- 5.0%) and QGS-FBP without RC (76.9 +/- 8.4%, P < .0001), QGS-OSEM with RC (76.6 +/- 8.6%, P < .0001), and cardioREPO-FBP without RC (72.1 +/- 10.0%, P = .0011), no significant difference was observed between Echo and cardioREPO-OSEM with RC (67.4 +/- 6.1%) in SH group. Conclusions. In pediatric gated myocardial perfusion SPECT, the SH effect can be significantly reduced when an OSEM algorithm is used with RC in combination with the specific cardioREPO algorithm.
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| 12. |
- Baek, Sungmin, et al.
(author)
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The Alternative Splicing Regulator Nova2 Constrains Vascular Erk Signaling to Limit Specification of the Lymphatic Lineage
- 2019
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In: Developmental Cell. - : CELL PRESS. - 1534-5807 .- 1878-1551. ; 49:2, s. 279-292
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Journal article (peer-reviewed)abstract
- The correct assignment of cell fate within fields of multipotent progenitors is essential for accurate tissue diversification. The first lymphatic vessels arise from pre-existing veins after venous endothelial cells become specified as lymphatic progenitors. Prox1 specifies lymphatic fate and labels these progenitors; however, the mechanisms restricting Prox1 expression and limiting the progenitor pool remain unknown. We identified a zebrafish mutant that displayed premature, expanded, and prolonged lymphatic specification. The gene responsible encodes the regulator of alternative splicing, Nova2. In zebrafish and human endothelial cells, Nova2 selectively regulates pre-mRNA splicing for components of signaling pathways and phosphoproteins. Nova2-deficient endothelial cells display increased Mapk/Erk signaling, and Prox1 expression is dynamically controlled by Erk signaling. We identify a mechanism whereby Nova2-regulated splicing constrains Erk signaling, thus limiting lymphatic progenitor cell specification. This identifies the capacity of a factor that tunes mRNA splicing to control assignment of cell fate during vascular differentiation.
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| 13. |
- Qi, QB, et al.
(author)
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Dietary Intake, FTO Genetic Variants, and Adiposity: A Combined Analysis of Over 16,000 Children and Adolescents
- 2015
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In: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 64:7, s. 2467-2476
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Journal article (peer-reviewed)abstract
- The FTO gene harbors variation with the strongest effect on adiposity and obesity risk. Previous data support a role for FTO variation in influencing food intake. We conducted a combined analysis of 16,094 boys and girls aged 1–18 years from 14 studies to examine the following: 1) the association between the FTO rs9939609 variant (or a proxy) and total energy and macronutrient intake; and 2) the interaction between the FTO variant and dietary intake, and the effect on BMI. We found that the BMI-increasing allele (minor allele) of the FTO variant was associated with increased total energy intake (effect per allele = 14.3 kcal/day [95% CI 5.9, 22.7 kcal/day], P = 6.5 × 10−4), but not with protein, carbohydrate, or fat intake. We also found that protein intake modified the association between the FTO variant and BMI (interactive effect per allele = 0.08 SD [0.03, 0.12 SD], P for interaction = 7.2 × 10−4): the association between FTO genotype and BMI was much stronger in individuals with high protein intake (effect per allele = 0.10 SD [0.07, 0.13 SD], P = 8.2 × 10−10) than in those with low intake (effect per allele = 0.04 SD [0.01, 0.07 SD], P = 0.02). Our results suggest that the FTO variant that confers a predisposition to higher BMI is associated with higher total energy intake, and that lower dietary protein intake attenuates the association between FTO genotype and adiposity in children and adolescents.
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| 14. |
- Wortelen, H., et al.
(author)
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Spin-orbit influence on dz2 -type surface state at Ta(110)
- 2015
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In: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 92:16
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Journal article (peer-reviewed)abstract
- The influence of spin-orbit interaction on an occupied surface state at Ta(110) is investigated with spin- and angle-resolved photoemission and electronic structure calculations. The surface state appears in a symmetry gap at a binding energy of 0.45 eV at Γ¯ and exhibits a free-electron-like E(k) dispersion with an effective mass m∗/me of about -1.35 along Γ¯H¯. Photoemission results for excitation with s- and p-polarized light confirm the predicted dz2-type symmetry of the state close to Γ¯. Spin-resolved data for finite k reveal a pure Rashba-type spin texture with a Rashba parameter of 0.063±0.007eVÅ. These findings clearly prove a sizable impact of spin-orbit coupling on the dz2 surface state and resolve a longstanding disagreement on this issue.
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| 15. |
- Yamada, K., et al.
(author)
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Targeted Therapy for Low Back Pain in Elderly Degenerative Lumbar Scoliosis
- 2016
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In: Spine. - : Ovid Technologies (Wolters Kluwer Health). - 0362-2436. ; 41:10, s. 872-879
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Journal article (peer-reviewed)abstract
- Study Design. Prospective cohort study. Objective. To compare the novel treatment procedure with nonoperative treatment for low back pain (LBP) in elderly patients with degenerative lumbar scoliosis (DLS). Summary of Background Data. Treatment of LBP associated with elderly DLS is controversial. We developed a novel treatment procedure, termed percutaneous intervertebral-vacuum polymethylmethacrylate injection (PIPI). Methods. We included patients with de novo DLS aged >= 65 years who had LBP with a visual analogue scale (VAS) score of >50 for >= 6 months with intervertebral vacuum and vertebral bone marrow edema (BME) defined on fat-saturated T2-weighted or gadolinium-enhanced T1-weighted magnetic resonance imaging. The primary outcomes were evaluated using the VAS score and modified Oswestry Disability Index (ODI). As an objective measurement, we scored BME on magnetic resonance imaging. Results. Between August 2004 and July 2011, 109 patients underwent PIPI and 53 received nonoperative treatment. At 1 month, mean improvements in VAS scores were -55.3 (95% CI, -60.5 to -50.1) and -1.9 (CI, -7.7 to 3.8) and mean improvements in ODI were -22.7 (CI, -27.3 to -18.2) and -0.6 (CI, -6.6 to 5.4) for the PIPI and nonoperative groups, respectively. At 2 years, mean improvements in VAS scores were -52.2 (CI, -59.9 to -44.4) and -4.0 (CI, -10.9 to 3.0) and mean improvements in ODI were -20.7 (CI, -27.3 to -14.5) and -1.0 (CI, -7.7 to 5.7) for the PIPI and nonoperative groups, respectively. BME substantially decreased in the PIPI group compared with the nonoperative group (P < 0.001) and correlated with VAS score and ODI improvements (VAS score: r = 0.502, P < 0.001; ODI: r = 0.372, P< 0.001). Conclusion. PIPI improved treatment for LBP, with a sustained clinical benefit for at least 2 years.
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