High-efficiency optical energy transfer between dissimilar waveguides is critical for establishing seamless interconnects between heterogeneous photonic systems. Broadband optical coupling between a ...silica single-mode optical fiber and a silicon integrated waveguide at near-infrared wavelengths has been especially challenging because of significant differences in their refractive indices and waveguide dimensions. We demonstrate highly efficient broadband optical coupling based on adiabatic mode transformation between axially overlapped tapered waveguides, with a specific focus on TE polarization. Sub-decibel optical coupling losses across the entire telecommunication O- and C-bands with large mechanical misalignment tolerances may significantly lower the connectivity barrier between low-loss optical fibers and densely integrated photonic devices for various emerging applications in both classical and quantum photonics.
According to the development plan for the Korea Space Launch Vehicle, a performance verification satellite will be installed in the launch vehicle in 2021. In addition, three payloads, including a ...small electrically heated thermoelectric generator (ETG), will be developed and installed in the satellite. In particular, a small ETG has been developed by the Korea Atomic Energy Research Institute for the purpose of evaluating the characteristics of the ETG in the space environment prior to the development of a radioisotope thermoelectric generator for lunar missions. In this study, shock and vibration tests were carried out to check whether the ETG can endure the launch environment of the spacecraft. In addition, a thermal cycle test and a thermal vacuum test were conducted to check whether the ETG maintains its performance, even at drastic temperature changes, which can be applied to the ETG in space. Finally, a periodic performance test was carried out to measure the degradation level of the small ETG.
The Korea Aerospace Research Institute is planning to launch a satellite for the Korea launch vehicle's low orbit test in 2021. An electrically heated thermoelectric generator (ETG) with a mass of ...850 g (small ETG) will be one of its selected payloads for this test flight. To assess and assure the design heritage and the reliability of the ETG in the space environment, a small ETG will be tested at the top of the satellite for more than a year. In this study, the design for a small ETG with 10 W(thermal) of heat input was developed through simulations such as heat transfer analysis, modal analysis, thermoelectric analysis, and structural analysis. Then a mock-up was fabricated and basic performance tests were carried out to be ready for the space environment test.
This study aimed to evaluate children with lymphoblastic leukemia and examine the potential correlation between corticospinal tract (CST) injury and motor dysfunction prior to chemotherapy using ...diffusion tensor tractography (DTT). Nineteen consecutive patients with childhood leukemia (mean age 7.483 ± 3.1 years, range 4-12 years) with unilateral motor dysfunction who underwent DTT prior to chemotherapy and twenty healthy individuals (mean age 7.478 ± 1.2 years; range 4-12 years) were enrolled. Motor functions were evaluated by two independent investigators. The cause of neurological dysfunction was identified based on the CST state using mean fractional anisotropy (FA), mean fiber volume (FV), and CST integrity using DTT. All patients showed disrupted integrity and significantly decreased FA and FV in the affected CST compared to the unaffected CST and the control group (
< 0.05). These DTT results also corresponded to patients' unilateral motor dysfunction. Using DTT, we demonstrated that neurological dysfunction may occur in patients with childhood acute lymphoblastic leukemia even prior to chemotherapy, and that CST injuries correlate with motor dysfunction in these patients. DTT may be a useful modality for evaluating the neural tract state in pediatric leukemia patients with neurological dysfunction.
Nickel (Ni) and Ni-63 films were synthesized by direct current electrodeposition. The composition of an alkaline electrolyte was ammonium citrate (25 g/l), hydrazine hydrate (25 g/l), and ammonium ...solution (25%) for adjusting the pH to 10. The acidic electrolyte at pH 4 was prepared using a full chloride bath. A higher deposition yield (92%) of the citrate electrolyte (pH 10) than 73% of acidic electrolyte (pH4) was measured using ICP. The deposition yield of radioactive Ni-63 in a citrate bath was also same as natural Ni in alkaline electrolyte. A newly prepared alkaline bath for the deposition of Ni-63 can be a solution for an extremely decreased radio-activity in the waste after plating.
Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer. Neoadjuvant systemic therapy (NAST) followed by surgery are currently standard of care for TNBC with 50-60% of patients ...achieving pathologic complete response (pCR). We investigated ability of deep learning (DL) on dynamic contrast enhanced (DCE) MRI and diffusion weighted imaging acquired early during NAST to predict TNBC patients' pCR status in the breast. During the development phase using the images of 130 TNBC patients, the DL model achieved areas under the receiver operating characteristic curves (AUCs) of 0.97 ± 0.04 and 0.82 ± 0.10 for the training and the validation, respectively. The model achieved an AUC of 0.86 ± 0.03 when evaluated in the independent testing group of 32 patients. In an additional prospective blinded testing group of 48 patients, the model achieved an AUC of 0.83 ± 0.02. These results demonstrated that DL based on multiparametric MRI can potentially differentiate TNBC patients with pCR or non-pCR in the breast early during NAST.
This paper presents the drop performance test of the control rod assembly which is one of the main components strongly related to the safety of the prototype generation IV sodium-cooled fast reactor. ...To investigate the drop performance, a real-sized control rod assembly that was recently modified based on the drop analysis results was newly fabricated, and several free drop tests under different flow rate conditions were carried out. Then the results were compared with those obtained from the previous tests conducted on the conceptually designed control rod assembly to demonstrate the improvement in performance. Moreover, the drop performance tests under several types and magnitudes of seismic loadings were also conducted to investigate the effect of the seismic loading on the drop performance of the modified control rod assembly. The results showed that the effects of the type and magnitude of the seismic loading on the drop performance of the modified control rod assembly were not significant. Also, the drop time requirement was successfully satisfied, even under the seismic loading conditions. Keywords: Sodium-cooled fast reactor, Control rod assembly, Drop performance test, Seismic loading, Drop time
Early assessment of neoadjuvant systemic therapy (NAST) response for triple-negative breast cancer (TNBC) is critical for patient care in order to avoid the unnecessary toxicity of an ineffective ...treatment. We assessed functional tumor volumes (FTVs) from dynamic contrast-enhanced (DCE) MRI after 2 cycles (C2) and 4 cycles (C4) of NAST as predictors of response in TNBC. A group of 100 patients with stage I-III TNBC who underwent DCE MRI at baseline, C2, and C4 were included in this study. Tumors were segmented on DCE images of 1 min and 2.5 min post-injection. FTVs were measured using the optimized percentage enhancement (PE) and signal enhancement ratio (SER) thresholds. The Mann-Whitney test was used to compare the performance of the FTVs at C2 and C4. Of the 100 patients, 49 (49%) had a pathologic complete response (pCR) and 51 (51%) had a non-pCR. The maximum area under the receiving operating characteristic curve (AUC) for predicting the treatment response was 0.84 (
< 0.001) for FTV at C4 followed by FTV at C2 (AUC = 0.82,
< 0.001). The FTV measured at baseline was not able to discriminate pCR from non-pCR. FTVs measured on DCE MRI at C2, as well as at C4, of NAST can potentially predict pCR and non-pCR in TNBC patients.
Early prediction of neoadjuvant systemic therapy (NAST) response for triple-negative breast cancer (TNBC) patients could help oncologists select individualized treatment and avoid toxic effects ...associated with ineffective therapy in patients unlikely to achieve pathologic complete response (pCR). The objective of this study is to evaluate the performance of radiomic features of the peritumoral and tumoral regions from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) acquired at different time points of NAST for early treatment response prediction in TNBC. This study included 163 Stage I-III patients with TNBC undergoing NAST as part of a prospective clinical trial (NCT02276443). Peritumoral and tumoral regions of interest were segmented on DCE images at baseline (BL) and after two (C2) and four (C4) cycles of NAST. Ten first-order (FO) radiomic features and 300 gray-level-co-occurrence matrix (GLCM) features were calculated. Area under the receiver operating characteristic curve (AUC) and Wilcoxon rank sum test were used to determine the most predictive features. Multivariate logistic regression models were used for performance assessment. Pearson correlation was used to assess intrareader and interreader variability. Seventy-eight patients (48%) had pCR (52 training, 26 testing), and 85 (52%) had non-pCR (57 training, 28 testing). Forty-six radiomic features had AUC at least 0.70, and 13 multivariate models had AUC at least 0.75 for training and testing sets. The Pearson correlation showed significant correlation between readers. In conclusion, Radiomic features from DCE-MRI are useful for differentiating pCR and non-pCR. Similarly, predictive radiomic models based on these features can improve early noninvasive treatment response prediction in TNBC patients undergoing NAST.
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