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Intensifying Chelation of Pb-Related Defects for Enhancing Stability in Halide Perovskite Thin-Film Solar Cells
No full textHalide perovskite-based thin-film solar cells have achieved remarkable power conversion efficiency, yet stability issues linked to Pb-related defects pose significant challenges. These defects, predominantly forming during film fabrication, particularly at surfaces and grain boundaries, create nonradiative recombination centers that also accelerate device degradation. To mitigate these defects, a chelation-based passivation strategy is introduced, particularly through antisolvent additive engineering. A range of natural organic chelating agents, including adipic acid, malic acid, tartaric acid, and citric acid, is employed to passivate Pb-related defects by forming polydentate bonds with uncoordinated Pb2+ ions at surfaces and grain boundaries. This chelation-based passivation strategy effectively reduces nonradiative recombination and improves interfacial charge extraction. Notably, perovskite solar cells treated with citric acid demonstrate an increase in power conversion efficiency from 20.7% to 22.0%, along with sustained stability, maintaining over 90% of their initial efficiency after 150 h of operation under continuous illumination in ambient air without any encapsulation, highlighting the potential of environmentally friendly chelating agents in improving the performance and stability of perovskite solar cells.N
Cultivating vigilant drivers through TV: On the cultural work of dashcam videos and normalization of surveillance
No full textThis paper explores the cultural work of surveillance through the emerging YouTube genre of videos that feature footage from in-car video data recorders. South Korea's 'Han Moon Chul TV' (HMC TV) exemplifies this genre, inheriting and extending beyond the traditions of public service television for traffic safety. The analysis shows how HMC TV operates as a cultural technology that merges the previous goals of public service television with the visual language of automotive vision while also promoting the idea of self as a node of safety responsibility. The paper situates HMC TV within broader discussions on traffic safety, technological change, and surveillance normalization in the South Korean context, interrogating its role in shaping defensive rationality and vigilant driving behaviors. By incorporating surveillance technologies into regimes of safety, these representations help legitimize surveillance as a self-protection tool and a guarantor of truth, positioning it as a necessary defense against potential future threats.N
Automated Audit and Self-Correction Algorithm for Seg-Hallucination Using MeshCNN-Based On-Demand Generative AI
No full textRecent advancements in deep learning have significantly improved medical image segmentation. However, the generalization performance and potential risks of data-driven models remain insufficiently validated. Specifically, unrealistic segmentation predictions deviating from actual anatomical structures, known as a Seg-Hallucination, often occur in deep learning-based models. The Seg-Hallucinations can result in erroneous quantitative analyses and distort critical imaging biomarker information, yet effective audits or corrections to address these issues are rare. Therefore, we propose an automated Seg-Hallucination surveillance and correction (ASHSC) algorithm utilizing only 3D organ mask information derived from CT images without reliance on the ground truth. Two publicly available datasets were used in developing the ASHSC algorithm: 280 CT scans from the TotalSegmentator dataset for training and 274 CT scans from the Cancer Imaging Archive (TCIA) dataset for performance evaluation. The ASHSC algorithm utilizes a two-stage on-demand strategy with mesh-based convolutional neural networks and generative artificial intelligence. The segmentation quality level (SQ-level)-based surveillance stage was evaluated using the area under the receiver operating curve, sensitivity, specificity, and positive predictive value. The on-demand correction performance of the algorithm was assessed using similarity metrics: volumetric Dice score, volume error percentage, average surface distance, and Hausdorff distance. Average performance of the surveillance stage resulted in an AUROC of 0.94 +/- 0.01, sensitivity of 0.82 +/- 0.03, specificity of 0.90 +/- 0.01, and PPV of 0.92 +/- 0.01 for test dataset. After the on-demand refinement of the correction stage, all the four similarity metrics were improved compared to a single use of the AI-segmentation model. This study not only enhances the efficiency and reliability of handling the Seg-Hallucination but also eliminates the reliance on ground truth. The ASHSC algorithm offers intuitive 3D guidance for uncertainty regions, while maintaining manageable computational complexity. The SQ-level-based on-demand correction strategy adaptively minimizes uncertainties inherent in deep-learning-based organ masks and advances automated auditing and correction methodologies.Y
Exploring photosensitive nanomaterials and optoelectronic synapses for neuromorphic artificial vision
No full textArtificial vision systems will be essential in intelligent machine-vision applications such as autonomous vehicles, bionic eyes, and humanoid robot eyes. However, conventional digital electronics in these systems face limitations in system complexity, processing speed, and energy consumption. These challenges have been addressed by biomimetic approaches utilizing optoelectronic synapses inspired by the biological synapses in the eye. Nanomaterials can confine photogenerated charge carriers within nano-sized regions, and thus offer significant potential for optoelectronic synapses to perform in-sensor image-processing tasks, such as classifying static multicolor images and detecting dynamic object movements. We introduce recent developments in optoelectronic synapses, focusing on use of photosensitive nanomaterials. We also explore applications of these synapses in recognizing static and dynamic optical information. Finally, we suggest future directions for research on optoelectronic synapses to implement neuromorphic artificial vision.N
Dynamics of molecular heterogeneity in high-risk luminal breast cancer—From intrinsic to adaptive subtyping
No full textWe evaluate therapy-induced molecular heterogeneity in longitudinal samples from high-risk, hormone-receptor positive/HER2-negative breast cancer patients with residual tumor after neoadjuvant chemotherapy from the Penelope-B trial (NCT01864746; EudraCT 2013-001040-62). Intrinsic subtypes are prognostic in pre-therapeutic (Tx) samples (n = 629, p < 0.0001) and post-Tx residual tumors (n = 782, p < 0.0001). After neoadjuvant chemotherapy, a shift of intrinsic subtypes is observed from pre-Tx luminal (Lum) B to post-Tx LumA, with reverse transition back to LumB in metastases. In a combined analysis of 540 paired pre-Tx and post-Tx samples, we identify five adaptive clusters (AC-1–5) based on transcriptomic changes before and after neoadjuvant chemotherapy. These AC-subtypes are prognostic beyond classical intrinsic subtyping, categorizing patients into groups with excellent prognosis (AC-1 and AC-2), poor prognosis (AC-3 and AC-4), and very poor prognosis (AC-5, enriched for basal-like subtype). Our analysis provides a basis for an extended molecular classification of breast cancer patients and improved identification of high-risk patient populations.N
Optimizing inductance for minimizing reactive power in single-phase-shift modulated dual active bridge converters under variable input voltage
No full textThis paper proposes an optimal series inductance to minimize reactive power and conduction losses in the single-phase-shift modulation of a dual-active-bridge (DAB) converter. Considerable variations in the root mean square (RMS) current of the DAB converter occur due to changes in input voltages. This study visually analyzes the multivariate variation of RMS current in three-dimensional space, considering inductance and input voltage conditions. Additionally, the series inductance is optimized to ensure consistent performance under varying input voltages, using the coefficient of variation. Analytical examination and validation of RMS current changes with respect to series inductance under different input voltage conditions are conducted using a prototype 48 V-12 V DAB converter. Based on this analysis, an appropriate series inductance for optimizing performance is proposed.N
An Arctic sea ice concentration data record on a 6.25 km polar stereographic grid from 3 years of Landsat-8 imagery
No full textThe decline in Arctic sea ice in the global warming era has received much attention as a contributing factor to the changes in the weather and climate in the Arctic and beyond. The coverage of Arctic sea ice (i.e. sea ice concentration (SIC)) has been monitored since 1972 using satellite passive microwave (PMW) measurements because of their extensive coverage and all-weather capability. However, the fundamental basis of algorithms for estimating SIC has not improved much since the early days due to the lack of reference SIC data, leading to discrepancies between existing PMW SIC algorithms. To overcome this issue, this study aims to construct data records of reference SIC over Arctic sea ice using 30 m resolution imagery from the Operational Land Imager (OLI) on board Landsat-8. In order to collect relatively bright and clear scenes, thresholds of solar elevation >15 degrees and cloud cover <10 % were applied in this study. Clouds in each Landsat-8 scene were masked using the cloud-masking array provided in Landsat data. Due to the poor accuracy of the cloud-masking array over ice-covered surface types, an additional step of visually inspecting the state of the cloud mask using the true-colour image was designated in this study. Each Landsat-8 scene was sorted into four categories depending on the state of the cloud mask. The normalized difference snow index and OLI band-5 reflectivity were used to differentiate between ice and open water within each selected Landsat-8 pixel. The classified data were projected onto a 6.25 km polar stereographic grid, and SIC for each grid cell was obtained by counting ice-classified pixels within the grid. SIC was only computed for grid cells where more than 99 % of their area was covered with Landsat-8 pixels to limit the uncertainty in SIC arising from grids that are not fully concentrated with Landsat-8 pixels. Uncertainty in the produced SIC was 1 %-4 %, inferred using the Gaussian error propagation method. Out of 15 286 collected Landsat-8 images, 14 297 images were translated into SIC maps, and a total of 2 934 399 Landsat-8 SIC grid cells were generated. Evaluation of Landsat-8 SIC with SIC from ice charts revealed a good linear relationship (correlation coefficient of 0.96) between the two products, as well as a mean negative bias which fell within the uncertainty range of Landsat-8 SIC. SIC based on Landsat-8 can be used as reference SIC to evaluate existing SIC products, and, thus, one can improve SIC products, as well as use the improved SIC for other applications such as data assimilation and retrieval studies. The vast amount of Landsat-8 SIC generated in this study may also be used to train deep-learning models for the estimation of Arctic SIC coverage. The Landsat-8 SIC dataset can be publicly accessed at https://doi.org/10.5281/zenodo.10973297 (Jung et al., 2024), and the Python codes for the production and evaluation of the Landsat-8 SIC dataset are accessible at https://doi.org/10.5281/zenodo.12754602 (Jung, 2024).N
Comprehensive molecular analysis of 26 newly established human pancreatic ductal adenocarcinoma cell lines reveals two clusters with variating drug sensitivities
No full textBackgroundPancreatic ductal adenocarcinoma (PDAC) is a malignant form of cancer with the worst survival rate and an extremely low rate of response to treatments. The development and molecular characterization of pancreatic cancer cell lines (PCCLs) are essential for studying the biology of highly aggressive pancreatic adenocarcinoma.MethodsWe applied whole exome sequencing (WES) and RNA-seq to identify molecular characteristics of 26 newly established PCCLs. Eighteen clinically relevant anti-cancer drugs were used to assess highly heterogeneous drug responses across the 26 cell lines.ResultsWe confirmed that common driver mutations of PDAC were well retained in our cell lines through WES analysis. Transcriptomic analysis identified two representative clusters that correlated with responses to certain drugs. By using Moffitt's classification method, the two clusters, C1 and C2, showed comparable expression patterns to "Basal-like" and "Classical" types, respectively. Drug screening results showed varying responses among different cell lines. In our cohort, C2 displayed greater sensitivity to anti-cancer drugs compared to C1. Furthermore, drugs targeting similar molecular pathways exhibited corresponding reactions among cell lines.ConclusionsOur results underscored that transcriptomic features of pancreatic cancer correlate with drug sensitivity rather than with the effects of targeted drugs. Cell lines are useful in vitro model systems for studying the molecular mechanisms of PDAC.Y
CaV3.3 T-type calcium channels contribute to carboplatin resistance in retinoblastoma
No full textCarboplatin resistance in retinoblastoma, an aggressive pediatric intraocular tumor, remains a major clinical challenge in treatment. This study elucidates the role of T-type calcium channels in carboplatin resistance using human retinoblastoma Y79 cells. We generated carboplatin-resistant Y79 (Y79CR) cells and characterized their electrophysiological properties. Patch-clamp recordings revealed a subpopulation of enlarged Y79CR cells (i.e., giant cells) with hyperpolarized resting membrane potentials, reduced input resistance, and increased T-type calcium currents. Quantitative RT-PCR analysis confirmed upregulation of CaV3.3 mRNA in Y79CR cells, identifying CaV3.3 as the predominant channel mediating these currents. Pharmacological inhibition of CaV3.3 using ML218 and TAT-C3P attenuated the sustained currents and partially restored carboplatin sensitivity, as evidenced by decreased IC50 values in Y79CR cells. These findings demonstrate a critical role for T-type calcium channels, particularly CaV3.3, in mediating chemoresistance in retinoblastoma. Our results suggest that targeting these channels may provide a potential strategy to enhance the efficacy of carboplatin-based therapy in retinoblastoma treatment.Y
Genotype–Phenotype Correlations in 83 Korean X-linked Retinoschisis Patients: Impact of Retinoschisin 1 Secretion Profiles on Clinical Phenotypes
No full textPurpose: To assess the correlation between genotype and phenotype severity in X-linked juvenile retinoschisis (XLRS) by examining clinical and genetic features of a cohort of Korean XLRS patients. Design: Retrospective, observational study. Participants: Data from 83 consecutive male patients with molecularly confirmed XLRS were collected retrospectively. Methods: Clinical evaluation included best-corrected visual acuity (BCVA), fundus photography, spectral domain OCT (SD-OCT), and full-field electroretinography (ERG). Main Outcome Measures: The phenotypic characteristics of a cohort of pediatric Korean patients with XLRS, based on mutation types (truncating vs. missense) and secretory profile (secretion vs. nonsecretion), were assessed. Results: A total of 166 eyes of 83 patients were included. The mean age at diagnosis was 6.1 ± 8.8 years (range, 0.5–20.7 years), with a mean follow-up time of 9.2 ± 7.0 years (range, 0.6–24.3 years). The BCVA at first and last examination ranged from light perception to 0.1 logarithm of the minimum angle of resolution (mean ± standard deviation, 0.75 ± 0.59 and 0.82 ± 0.65, respectively). No significant differences were observed between the truncating (0.71 ± 0.51 and 0.75 ± 0.44) and missense (0.77 ± 0.59 and 0.84 ± 0.66) variants (P = 0.678 and 0.551). Clinical parameters from fundus photography, SD-OCT, and ERG showed no differences. However, BCVA was better for the secretion group (0.51 ± 0.24 and 0.61 ± 0.30) than for the nonsecretion group (0.65 ± 0.71 and 0.87 ± 0.81), with a significant difference in the last BCVA (P = 0.021). OCT revealed a higher frequency of ellipsoid zone disruption in the nonsecretion group (P = 0.030), with no significant differences in other parameters. Conclusions: The secretion profile of Retinoschisin 1 (RS1) could influence the severity of XLRS phenotypes. Patients with RS1-secreted mutants, particularly with intact octamerization, exhibit more homogeneous phenotypes and better visual acuity than the RS1-nonsecreted group. This data provide insights for studying genotype and phenotype correlations in both clinical and research fields. Financial Disclosure(s): The authors have no proprietary or commercial interest in any materials discussed in this article.N