253 research outputs found
Wavefront restoration from lateral shearing data using spectral interpolation
Although a lateral-shear interferometer is robust against optical component
vibrations, its interferogram provides information about differential
wavefronts rather than the wavefronts themselves, resulting in the loss of
specific frequency components. Previous studies have addressed this limitation
by measuring four interferograms with different shear amounts to accurately
restore the two-dimensional wavefront. This study proposes a technique that
employs spectral interpolation to reduce the number of required interferograms.
The proposed approach introduces an origin-shift technique for accurate
spectral interpolation, which in turn is implemented by combining two methods:
natural extension and least-squares determination of ambiguities in uniform
biases. Numerical simulations confirmed that the proposed method accurately
restored a two-dimensional wavefront from just two interferograms, thereby
indicating its potential to address the limitations of the lateral-shear
interferometer.Comment: 11 pages, 6 figure
A DISTANCE LEARNING SYSTEM WITH CUSTOMIZABLE SCREEN LAYOUTS FOR MULTIPLE LEARNING SITUATIONS
In this paper, we propose a new distance learning system that can adapt to various styles of learning activity. We assume that the system is used in distance classes with multiple live-streaming videos. Our system has functions to change the screen layout to best suit for the current learning situation for each of the participants in a class. The system also has a function to efficiently monitor the behavior of many students at a time. These functions enable us to adapt various learning activities in distance learning classes. We implemented
a prototype of the proposed system and evaluated it in experimental classes. We confirmed that our system improved the activities in the experimental classes
Establishment of anti-DKK3 peptide for the cancer control in head and neck squamous cell carcinoma (HNSCC)
Background: Head and neck squamous cell carcinoma (HNSCC) is the most common malignant tumor of the head and neck. We identified cancerāspecific genes in HNSCC and focused on DKK3 expression. DKK3 gene codes two isoāforms of proteins (secreted and nonāsecreted) with two distinct cysteine rich domains (CRDs). It is reported that DKK3 functions as a negative regulator of oncogenic Wnt signaling and, is therefore, considered to be a tumor suppressor gene. However, our series of studies have demonstrated that DKK3 expression is specifically high in HNSCC tissues and cells, and that DKK3 might determine the malignant potentials of HNSCC cells via the activation of Akt. Further analyses strongly suggested that both secreted DKK3 and nonāsecreted DKK3 could activate Akt signaling in discrete ways, and consequently exert tumor promoting effects. We hypothesized that DKK3 might be a specific druggable target, and it is necessary to establish a DKK3 inhibitor that can inhibit both secreted and nonāsecreted isoforms of DKK3.Methods: Using inverse polymerase chain reaction, we generated mutant expression plasmids that express DKK3 without CRD1, CRD2, or both CRD1 and CRD2 (DKK3ĪC1, DKK3ĪC2, and DKK3ĪC1ĪC2, respectively). These plasmids were then transfected into HNSCCāderived cells to determine the domain responsible for DKK3āmediated Akt activation. We designed antisense peptides using the MIMETEC program, targeting DKK3āspecific amino acid sequences within CRD1 and CRD2. The structural models for peptides and DKK3 were generated using Raptor X, and then a docking simulation was performed using CluPro2. Afterward, the best set of the peptides was applied into HNSCCāderived cells, and the effects on Akt phosphorylation, cellular proliferation, invasion, and migration were assessed. We also investigated the therapeutic effects of the peptides in the xenograft models.Results: Transfection of mutant expression plasmids and subsequent functional analyses revealed that it is necessary to delete both CRD1 and CRD2 to inhibit Akt activation and inhibition of proliferation, migration, and invasion. The inhibitory peptides for CRD1 and CRD2 of DKK3 significantly reduced the phosphorylation of Akt, and consequently suppressed cellular proliferation, migration, invasion and in vivo tumor growth at very low doses.Conclusions: This inhibitory peptide represents a promising new therapeutic strategy for HNSCC treatment
Chromosomal Organization and Sequence Diversity of Genes Encoding Lachrymatory Factor Synthase in Allium cepa L.
Lachrymatory factor synthase (LFS) catalyzes the formation of lachrymatory factor, one of the most distinctive traits of bulb onion (Allium cepa L.). Therefore, we used LFS as a model for a functional gene in a huge genome, and we examined the chromosomal organization of LFS in A. cepa by multiple approaches. The first-level analysis completed the chromosomal assignment of LFS gene to chromosome 5 of A. cepa via the use of a complete set of A. fistulosumāshallot (A. cepa L. Aggregatum group) monosomic addition lines. Subsequent use of an F2 mapping population from the interspecific cross A. cepa Ć A. roylei confirmed the assignment of an LFS locus to this chromosome. Sequence comparison of two BAC clones bearing LFS genes, LFS amplicons from diverse germplasm, and expressed sequences from a doubled haploid line revealed variation consistent with duplicated LFS genes. Furthermore, the BAC-FISH study using the two BAC clones as a probe showed that LFS genes are localized in the proximal region of the long arm of the chromosome. These results suggested that LFS in A. cepa is transcribed from at least two loci and that they are localized on chromosome 5
Development of a broadband superluminescent diode based on self-assembled InAs quantum dots and demonstration of high-axial-resolution optical coherence tomography imaging
We developed a near-infrared (NIR) superluminescent diode (SLD) based on self-assembled InAs quantum dots (QDs) and demonstrated high-axial-resolution optical coherence tomography (OCT) imaging using this QD-based SLD (QD-SLD). The QD-SLD utilized InAs QDs with controlled emission wavelengths as a NIR broadband light emitter, and a tilted waveguide with segmented electrodes was prepared for edge-emitting broadband electroluminescence (EL) spanning approximately 1ā1.3 Ī¼m. The bandwidth of the EL spectrum was increased up to 144ānm at a temperature of 25 Ā°C controlled using a thermoelectric cooler. The inverse Fourier transform of the EL spectrum predicted a minimum resolution of 3.6 Ī¼m in air. The QD-SLD was subsequently introduced into a spectral-domain (SD)-OCT setup, and SD-OCT imaging was performed for industrial and biological test samples. The OCT images obtained using the QD-SLD showed an axial resolution of ~4 Ī¼m, which was almost the same as that predicted from the spectrum. This axial resolution is less than the typical size of a single biological cell (~5 Ī¼m), and the practical demonstration of high-axial-resolution OCT imaging shows the application of QD-SLDs as a compact OCT light source, which enables the development of a portable OCT system
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