56 research outputs found
Real-time 3-D Mapping with Estimating Acoustic Materials
This paper proposes a real-time system integrating an acoustic material
estimation from visual appearance and an on-the-fly mapping in the 3-dimension.
The proposed method estimates the acoustic materials of surroundings in indoor
scenes and incorporates them to a 3-D occupancy map, as a robot moves around
the environment. To estimate the acoustic material from the visual cue, we
apply the state-of-the-art semantic segmentation CNN network based on the
assumption that the visual appearance and the acoustic materials have a strong
association. Furthermore, we introduce an update policy to handle the material
estimations during the online mapping process. As a result, our environment map
with acoustic material can be used for sound-related robotics applications,
such as sound source localization taking into account various acoustic
propagation (e.g., reflection)
Selective disruption of an oncogenic mutant allele by CRISPR/Cas9 induces efficient tumor regression
Approximately 15% of non-small cell lung cancer cases are associated with a mutation in the epidermal growth factor receptor (EGFR) gene, which plays a critical role in tumor progression. With the goal of treating mutated EGFR-mediated lung cancer, we demonstrate the use of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (Cas9) system to discriminate between the oncogenic mutant and wild-type EGFR alleles and eliminate the carcinogenic mutant EGFR allele with high accuracy. We targeted an EGFR oncogene harboring a single-nucleotide missense mutation (CTG > CGG) that generates a protospacer-adjacent motif sequence recognized by the CRISPR/Cas9 derived from Streptococcus pyogenes. Co-delivery of Cas9 and an EGFR mutation-specific single-guide RNA via adenovirus resulted in precise disruption at the oncogenic mutation site with high specificity. Furthermore, this CRISPR/Cas9-mediated mutant allele disruption led to significantly enhanced cancer cell killing and reduced tumor size in a xenograft mouse model of human lung cancer. Taken together, these results indicate that targeting an oncogenic mutation using CRISPR/Cas9 offers a powerful surgical strategy to disrupt oncogenic mutations to treat cancers; similar strategies could be used to treat other mutation-associated diseases.
Spotlight on nano-theranostics in South Korea: applications in diagnostics and treatment of diseases
Traveltime and amplitude calculation using a perturbation approach
Accurate amplitudes and correct traveltimes are critical
factors that govern the quality of prestack migration
images. Because we never know the correct velocity
initially, recomputing traveltimes and amplitudes
of updated velocity models can dominate the iterative
prestack migration procedure. Most tomographic velocity
updating techniques require the calculation of the
change of traveltime due to local changes in velocity.
For such locally updated velocity models, perturbation
techniques can be a significantly more economic way of
calculating traveltimes and amplitudes than recalculating
the entire solutions from scratch.
In this paper, we implement an iterative Born perturbation
theory applied to the damped wave equation
algorithm. Our iterative Born perturbation algorithm
yields stable solutions for models having velocity contrasts
of 30% about the initial velocity estimate, which is
significantly more economic than recalculating the entire
solution.This work was financially supported by National Research
Laboratory Project of the Korea Ministry of Science and Technology,
Brain Korea 21 project of the Korea Ministry of Education,
grant No. R05-2000-00003 from the Basic Research
Program of the Korea Science&Engineering Foundation, and
grant No. PM10300 from Korea Ocean Research & Development
Institute
Traveltime and amplitude calculations using the damped wave solution
Because of its computational efficiency, prestack
Kirchhoff depth migration remains the method of choice
for all but the most complicated geological depth structures.
Further improvement in computational speed and
amplitude estimation will allow us to use such technology
more routinely and generate better images. To this end,
we developed a new, accurate, and economical algorithm
to calculate first-arrival traveltimes and amplitudes for
an arbitrarily complex earth model. Our method is based
on numerical solutions of the wave equation obtained by
using well-established finite-difference or finite-element
modeling algorithms in the Laplace domain, where a
damping term is naturally incorporated in the wave
equation. We show that solving the strongly damped
wave equation is equivalent to solving the eikonal and
transport equations simultaneously at a fixed reference
frequency, which properly accounts for caustics and
other problems encountered in ray theory. Using our algorithm,
we can easily calculate first-arrival traveltimes
for given models. We present numerical examples for
2-D acoustic models having irregular topography and
complex geological structure using a finite-element modeling
code.This work was financially supported by National Research
Laboratory Project of the Korea Ministry of Science and
Technology, Brain Korea 21 project of the Korea Ministry of Education, grant No. R05-2000-00003 from the Basic Research
Program of the Korea Science&Engineering Foundation, and
grant No. PM10300 from Korea Ocean Research & Development
Institute
Enhanced optical response of hybridized VO2/graphene films
Application of graphene as transparent electrodes is an active research area due to its excellent electrical and optical properties. Vanadium dioxide (VO2) is an attractive material since it is a thermochromic material that undergoes a structural phase transition when heat is applied. The phase transition results in the change of electrical and optical characteristics. We report optical characteristics of hybrid materials of graphene and VO2. We observed a 12% improvement in infrared transmittance with VO2 films deposited on graphene sapphire substrates compared to that of bare sapphire substrates. We also found that the phase transition temperature decreases as the number of graphene layers on the substrates increases. In the case of VO2 films on the substrate that was coated with four layers of graphene, the mean phase transition temperature was lowered to similar to 56 degrees C.close4
The role of U.S. naval power in the Asia-pacific region: From regional protector to regional balancer
For more than four decades, U.S. engagement in the Asia-Pacific was centered on two premises: a Cold War commitment to Asian security and the remarkable economic power of the U.S. The U.S. Navy provided a symbol of the United States' commitment to protect its interests and those of its major Asian-pacific allies. Despite the end of the Cold War, the security environment of the Asia-Pacific region is still less changed and even a new threat of a regional naval arms race emerged in the 1990s. In this context, although forward deployments of U.S. military power in the Western Pacific have been scaled down, it is certain that the U.S. naval force will continue to play an important role as a key โregional balancer.โ Amid the collapse of the Soviet Union and in the post-Cold War era, the U.S. has still emphasized the maintenance of a U.S. forward-deployed presence and strong defense alliances with U.S. allies in order to prevent the emergence of regional hegemonic powers and to contribute to regional stability as well as improve U.S. economic interests. Moreover, in the face of a multitude of threats from state and non-state actors, the U.S. Navy is increasingly focused on and driven by the demands of peacetime and crisis forward presence.U.S. naval power, naval strategy, regional balancer, forward presence, Asia-Pacific region,
Multi-Modal Stacking Ensemble for the Diagnosis of Cardiovascular Diseases
Background: Cardiovascular diseases (CVDs) are a leading cause of death worldwide. Deep learning methods have been widely used in the field of medical image analysis and have shown promising results in the diagnosis of CVDs. Methods: Experiments were performed on 12-lead electrocardiogram (ECG) databases collected by Chapman University and Shaoxing Peopleโs Hospital. The ECG signal of each lead was converted into a scalogram image and an ECG grayscale image and used to fine-tune the pretrained ResNet-50 model of each lead. The ResNet-50 model was used as a base learner for the stacking ensemble method. Logistic regression, support vector machine, random forest, and XGBoost were used as a meta learner by combining the predictions of the base learner. The study introduced a method called multi-modal stacking ensemble, which involves training a meta learner through a stacking ensemble that combines predictions from two modalities: scalogram images and ECG grayscale images. Results: The multi-modal stacking ensemble with a combination of ResNet-50 and logistic regression achieved an AUC of 0.995, an accuracy of 93.97%, a sensitivity of 0.940, a precision of 0.937, and an F1-score of 0.936, which are higher than those of LSTM, BiLSTM, individual base learners, simple averaging ensemble, and single-modal stacking ensemble methods. Conclusion: The proposed multi-modal stacking ensemble approach showed effectiveness for diagnosing CVDs
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Synthesis of Highly Enantiomerically Enriched N-Boc-a-amino Ketones from Pseudoephedrine N-Boc-a-amino Acid Amides
N-Boc-alpha-amino ketones are synthesized efficiently and in high enantiomeric excess by the addition of organolithium and Grignard reagents to pseudoephedrine amides of N-Boc-alpha-amino acids, themselves available by the alkylation of pseudoephedrine glycinamide followed by N-protection.Chemistry and Chemical Biolog
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A One-Step Synthesis of Pseudoephedrine Glycinamide, a Versatile Precursor for the Synthesis of a-Amino Acids
Both enantiomers of a pseudoephedrine glycinamide [(+)- or (-)-1] were synthesized by either of two procedures: (1) a standard two-step coupling of N-Boc-Gly with pseudoephedrine followed by deprotection, or (2) a more economical one-step coupling reaction of Gly-OMe with pseudoephedrine mediated by LiCl and base.Chemistry and Chemical Biolog
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